Patent Application
20190083462
This disclosure relates to methods and compositions for addressing conditions of dysbiosis and/or inflammation, such as enteropathy, associated with administration of non-steroidal anti-inflammatory drug (NSAID).
Non-steroidal anti-inflammatory drugs (NSAIDs) are among the most frequently used medications worldwide for routine relief of pain or fever, to manage various forms of arthritis and inflammatory intestinal disorders, and to prevent or treat alimentary cancers. Despite their effectiveness for managing these varied and highly prevalent conditions, NSAIDs cause damage to the gastrointestinal (GI) tract. Although methods for diagnosis and effective treatment of NSAID-induced lesions of the proximal GI tract (i.e., gastropathy) have been well documented, the pathogenesis, diagnosis, and treatment of NSAID-induced damage of the GI tract distal to the duodenum (known as NSAID enteropathy, primarily affecting the distal jejunum and ileum) remain unclear. The magnitude of the problem of NSAID enteropathy is alarmingly high. In the United States, NSAID enteropathy results in approximately 100,000 hospitalizations and 16,500 deaths each year. Additionally, two-thirds of both short- and long-term NSAID users develop distal small intestinal lesions. Although the use of either NSAIDs considered to be safer for the GI tract or other ancillary therapies have reduced the incidence and severity of NSAID-induced gastropathy, the incidence of NSAID enteropathy has remained constant or has increased.
In view of the foregoing, there is a need for compositions and methods to ameliorate or prevent side effects, such as enteropathy, associated with NSAID administration. The present disclosure addresses this and related needs.
This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.
In one aspect, the disclosure provides a method of treating dysbiosis of commensal microbiota in a subject. The method comprises administering an effective amount of a tryptophan derived microbiota metabolite (TDMM), or a precursor, prodrug, or acceptable salt thereof, to a subject in need thereof.
In one embodiment, the subject has received or is expected to receive administration of an agent suspected to cause dysbiosis. In one embodiment, the agent causes a reduction in a gram-positive component of the microbiota. In one embodiment, the agent causes an increase in a gram-negative component of the microbiota. In one embodiment, the agent is a non-steroid anti-inflammatory drug (NSAID). In one embodiment, the TDMM is indole. In one embodiment, the TDMM, or a precursor, prodrug, or acceptable salt thereof, is co-administered with the agent. In one embodiment, the TDMM, or a precursor, prodrug, or acceptable salt thereof, is administered in a pharmaceutical composition that also comprises the agent. In one embodiment, the TDMM is administered by intra-peritoneal (IP), intravenous (IV), topical, parenteral, intradermal, transdermal, oral (e.g., via liquid or pill), or respiratory (e.g., intranasal mist) routes. In one embodiment, the subject is a mammal, such as a human or rodent. In one embodiment, treating the dysbiosis prevents or ameliorates enteropathy.
In another aspect, the disclosure provides a method of treating enteropathy associated with NSAID in a subject. The method comprises administering an effective amount of a tryptophan derived microbiota metabolite (TDMM), or a precursor, prodrug, or acceptable salt thereof, to a subject in need thereof. In one embodiment, the NSAID causes a reduction in a gram-positive component of the microbiota. In one embodiment, the NSAID causes an increase in a gram-negative component of the microbiota. In one embodiment, the NSAID is selected from aspirin, salsalate, celecoxib, diclofenac, etodolac, ibuprofen, indomethacin, ketoprofen, ketorolac, nabumetone, naproxen, oxaprozin, piroxicam, sulindac, meloxicam, tolmetin, and the like. In one embodiment, the TDMM is indole. In one embodiment, the effective amount of indole is at least about 5 mg/kg. In one embodiment, the TDMM, or a precursor, prodrug, or acceptable salt thereof, is co-administered with the NSAID. In one embodiment, the TDMM, or a precursor, prodrug, or acceptable salt thereof, is administered in a pharmaceutical composition that also comprises the NSAID. In one embodiment, the TDMM is administered by intra-peritoneal (IP), intravenous (IV), topical, parenteral, intradermal, transdermal, oral (e.g., via liquid or pill), or respiratory (e.g., intranasal mist) routes. In one embodiment, the subject is a mammal, such as a human or rodent.
In another aspect, the disclosure provides a method of treating a condition characterized by inflammation in the GI tract. The method comprises administering an effective amount of a tryptophan derived microbiota metabolite (TDMM), or a precursor, prodrug, or acceptable salt thereof, to a subject in need thereof. In one embodiment, the inflammation is associated with administration of an NSAID to the subject.
In another aspect, the disclosure provides a pharmaceutical composition comprising: at least one TDMM, or a precursor, prodrug, or acceptable salt thereof; at least one NSAID composition, or a precursor, prodrug, or acceptable salt thereof and a pharmaceutically acceptable carrier. In one embodiment, the TDMM is indole.
The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
The pathophysiology of NSAID enteropathy is complex and incompletely understood. It appears to involve deleterious effects of NSAIDs on the intestinal mucosa including enterocyte cell death, increased mucosal permeability, and interaction of the damaged mucosa with luminal contents including bacteria (GI microbiota) and bacterial products or components such as lipopolysaccharide (LPS). The GI microbiota has been implicated as an important contributor to NSAID enteropathy. For example, administration of NSAIDs causes a dysbiosis characterized by a reduction of the predominately gram-positive phylum Firmicutes and a corresponding increase of gram-negative bacteria. Germ-free rats lacking intestinal microbiota do not develop NSAID enteropathy, whereas they develop NSAID-induced intestinal lesions when colonized with gram-negative bacteria. Concurrent administration of NSAIDs and antimicrobials targeting gram-negative bacteria reduces the severity of NSAID-induced gastrointestinal lesions in rats.
In view of the role of some components of the microbiota in exacerbating NSAID enteropathy, the inventors investigated the whether there might be microbiota-derived metabolites that could mitigate gut inflammation and other pathology that characterizes NSAID enteropathy. As described in more detail below, the inventors examined the interaction of the host, the NSAID indomethacin, and a microbiota-derived metabolite, indole, in a murine model of NSAID enteropathy. The inventors surprisingly demonstrated that co-administration of indole attenuated NSAID-induced intestinal damage via a number of classic metrics. Notably, the inventors observed that co-administration of indole prevented the classic NSAID-induced shift of the microbiota, an important aspect of the pathophysiology of NSAID enteropathy. Additionally, the inventors performed RNA-sequencing of the small intestinal mucosa (representing an in vivo analysis of the transcriptome of NSAID enteropathy) and examined how the co-administration of indole altered this transcriptome. This dataset is available to the public (NCBI accession number PRJNA290483).
Accordingly, in view of the foregoing, in one aspect the disclosure provides a method of treating dysbiosis of commensal microbiota in a subject. The method comprises administering an effective amount of a tryptophan derived microbiota metabolite (TDMM), or a precursor or prodrug thereof.
As used herein, the term “treating” means preventing, reducing, slowing, or ameliorating symptoms associated with the indicated condition.
As used herein, the term “dysbiosis” refers to an imbalance of the diverse microbial community that inhabits the intestinal tract of a subject (e.g., vertebrate host). The commensal microbial community is also referred to herein as “microbiota”. In some embodiments, the dysbiosis leads to or is correlated with enteropathy. As used herein, the term “enteropathy” refers to the presence of lesions in the region of the gastrointestinal (GI) tract that is generally distal to the duodenum. In some embodiments, this region includes at least a portion of the distal jejunum and ileum. Accordingly, in some embodiments of this aspect, treating dysbiosis refers to preventing, reducing, slowing, or ameliorating the symptoms associated with enteropathy. In some embodiments, the enteropathy is associated with the agent, such as with administration of an NSAID.
In some embodiments, the dysbiosis is associated with inflammation and/or other pathologies similar to enteropathy, such as experienced in disorders such as colitis, inflammatory bowel disease (IBD), psoriasis, rheumatoid arthritis, multiple sclerosis, and the like. While the methods generally disclosed herein are described mostly in the context of NSAID enteropathy, it is known that several signaling target that have a role in enteropathy, such as stat3, akt, and mTor, also play a role in such other inflammatory diseases. Accordingly, such other diseases and conditions are encompassed by the present disclosure.
As used herein, the term “effective amount” or “therapeutically effective” amount refers to a sufficient quantify or concentration of the agent, e.g., TDMM, so as to elicit an intended result, such as prevention or reduction of dysbiosis. Effective amounts can be readily determined and optimized per normal
As used herein, the term “tryptophan derived microbiota metabolite” (“TDMM”) refers to metabolites produced by microorganisms of the commensal microbiota that resides in the intestinal tract. The individuals of the microbiota inhabit the space of the intestines and exist in homeostasis with the healthy vertebrate host. Thus, presumably, the metabolite products produced by the individuals of the microbiota have been selected over time to promote a stable environment beneficial to both the microbiota and host. For example, such beneficial environment is one that is adverse to colonization by pathogens or that avoid inflammatory conditions in the mucosa. Specific metabolites referred to by the term TDMM are derivatives of tryptophan and include compounds such as indole, hydroxyindole (e.g., 2-hydroxyindole, 3 -hydroxyindole, 5-hydroxyindole, 7-hydroxyindole), 1-(2-carboxyphenylamino)-1-deoxy-D-ribulose-5-phosphate, 5-Hydroxy-L-tryptophan, indoleglycerol phosphate, indolepyruvate, N-(5-Phospho-D-ribosyl)anthranilate, tryptamine, indole-3-acetate, L-formylkynurenine, L-Tryptophanyl-tRNA(Trp), indole-3-acetamide, indole-3-pyruvate, indole-3-lactic acid, tryptophol, indole-3-acetaldehyde, indole-3-aldehyde, isatin (indole-2,3-dione), isoindigo, indirubin, indoxyl-sulfate, and 2-oxyindole. The TDMM encompasses such molecules that have been directly obtained from microbiota individuals. Such TDMMs can be isolated, purified, or partially purified through well-established methods. However, the term TDMM, while referring to the feature of a “microbiota metabolite,” is not necessarily limited to the specific source of one or more individual organisms from the commensal microbiota. Instead, it merely refers to the fact that commensal microorganisms of the microbiota are known to produce such a compound. Thus, the TDMM used as part of this disclosure can also be obtained from an organism that is not typically considered to be a member of a commensal microbiota of a vertebrate organism (whether the vertebrate individual is the source of the naïve T cell or not). Instead, the TDMM can be produced by known methods, such as typical recombinant approaches, in preferred laboratory strains of bacteria, and the like. Furthermore, the TDMM can be produced synthetically, as appropriate through known methods of synthetic chemistry. In any of the above embodiments, the subject can be administered with a composition that is a precursor to or prodrug of any of the above listed TDMM compound embodiments.
In one embodiment, the TDMM is indole, which is typically represented with the following structure:
In some embodiments, the subject has received or is expected to receive an administration of an agent, e.g., drug, with a suspected side-effect of causing dysbiosis. As described above, some agents associated with dysbiosis have been shown to result in the reduction of gram-positive bacteria in the phylum Firmicutes. Accordingly, in some embodiments, the agent is known to cause a relative decrease in a gram-positive component of the microbiota, such as bacteria in the phylum Firmicutes. In some embodiments, the agent is known to cause a relative increase in a gram-negative component in the microbiota.
In some embodiments, the agent is a nonsteroidal anti-inflammatory drug (NSAID).
The term “nonsteroidal anti-inflammatory drug” or the abbreviation “NSAID” refers to a class of drugs that are typically used for analgesic and antipyretic purposes, although they are also used in higher doses for anti-inflammatory effects. Due to non-addictive characteristics, NSAIDs are often used as alternatives to narcotic drugs. Most NSAIDs inhibit the activity of cyclooxygenase-1 (COX-1) and cyclooxygenase-2 (COX-2), and thereby, the synthesis of prostaglandins and thromboxanes. It is thought that inhibiting COX-2 leads to the anti-inflammatory, analgesic and antipyretic effects. Most relevant to the present disclosure are NSAIDs that cause adverse reactions in the intestinal tract, especially dysbiosis in the microbiota and enteropathy. Exemplary, non-limiting NSAIDs relevant to the present disclosure are set forth in TABLE 1.
Temporally, the TDMM can be administered prior to, concurrently with, or after administration of the agent. It is within the skill of the ordinary artisan to determine and optimize the most efficacious regimen of pre-, co-, and/or post-administration of the TDMM relative to the agent. Furthermore, it will be appreciated that multiple administrations of the TDMM relative to one or more exposures to the agent are encompassed by the present disclosure. Again, determining and optimizing such administration regimens is within the skill of the ordinary artisan.
Administration of the TDMM can be in any appropriate route of administration. For example, the TDMM can be administered by intra-peritoneal (IP), intravenous (IV), topical, parenteral, intradermal, transdermal, oral (e.g., via liquid or pill), rectal, or respiratory (e.g., intranasal mist) routes. In preferred embodiments, the TDMM is ingested, e.g., via liquid or pill, etc. to facilitate delivery of the TDMM to the intestinal tract where the microbiota reside.
The effective amount of TDMM, or a precursor or prodrug thereof, can depend on factors pertaining to the subject and the route of administration, etc., and can be readily determined according to the skill of the ordinary artisan. In some embodiments, a single administration (of potentially one or multiple administrations) comprises at least about 1 mg/kg, 5 mg/kg, 15 mg/kg, 20 mg/kg, 25 mg/kg, 30 mg/kg, 35 mg/kg, 40 mg/kg, 45 mg/kg, 50 mg/kg, 55 mg/kg, 60 mg/kg, 65 mg/kg, 70 mg/kg, 75 mg/kg, 80 mg/kg, 85 mg/kg, 90 mg/kg, 95 mg/kg, 100 mg/kg, or more. Dosing can be readily determined for any particular subject based on routine cell and animal toxicity studies so as to avoid deleterious effects of high concentrations, while still achieving the desired effect.
In some embodiments, the microbiota of the subject is induced to produce elevated levels of the appropriate TDMM, such as indole. In this regard, additional microbiota organisms that are known to produce high levels of the TDMM can be administered to the subject. In some embodiments, the administered microbiota organisms can be artificially selected or genetically engineered to produce higher levels of the TDMM when residing in the GI tract of the subject. For example, in some embodiments the genetically engineered microorganisms are engineered to express, stably or transiently, higher levels of a tnaA gene, which encodes the enzyme responsible for tryptophan metabolism and production of indole. Alternatively or additionally, the subject can be provided with elevated levels of tryptophan, such as in dietary supplements, so as to allow the microbiota to produce higher levels of TDMMs.
The subject can be any organism for which maintenance of a balance of commensal microbiota in the intestinal tract is desired. The subject can be any vertebrate, including birds (e.g., chickens) and mammals, including primates (such as humans); rodents (such as mouse, rat, and guinea pig); cat; dog; cow; horse; sheep; pig; and the like.
In another aspect, the disclosure provides a method of treating an inflammatory disease or condition. In some embodiments, the condition is characterized by inflammation in the gut. In some embodiments, the disease or condition is enteropathy associated with NSAID (i.e., “NSAID-enteropathy”) in a subject. As described above, other diseases or conditions involve inflammation and/or other pathologies similar to enteropathy, such as experienced in disorders such as colitis, inflammatory bowel disease (IBD), psoriasis, rheumatoid arthritis, multiple sclerosis, and the like. It is known that several signaling target that have a role in enteropathy, such as stat3, akt, and mTor, also play a role in such other inflammatory diseases. Accordingly, such other diseases and conditions are encompassed by the present disclosure.
In this aspect, the method comprises administering an effective amount of a TDMM, or TDMM precursor, to the subject, as described above. As described, in some embodiments, at least some components of the microbiota are induced to produce higher levels of the TDMM.
In some embodiments, administration of the NSAID to the subject has caused or is suspected of being capable of causing enteropathy in the subject. In some embodiments, the NSAID has caused or is suspected of causing the relative decrease of a gram-positive component in the microbiota, and/or conversely the NSAID has caused or is suspected of causing the relative increase of a gram-negative component of the microbiota.
Representative NSAIDs and TDMMs, and their administrations, are described above.
In another aspect, the disclosure provides a pharmaceutical composition comprising at least one TDMM, or precursor or prodrug thereof, as described above. If derived from microbiota or a bacterial source, the TDMM is preferably isolated or substantially isolated from the bacterial source. In some embodiments, the pharmaceutical composition also comprises at least one NSAID composition, as described above. Accordingly, the disclosure provides for a pharmaceutical composition with co-formulation of an NSAID and a TDMM appropriate for a single, effective dose in a subject that reduces the chance or severity of enteropathy in the subject due to the NSAID.
As the present disclosure has established that administration of a TDMM has ameliorative and/or therapeutic effects for inflammation of the gut, for example, as caused by NSAID administration, the disclosure also provides a method of treating a condition characterized by inflammation in the GI tract. The method comprises administering an effective amount of a tryptophan derived microbiota metabolite (TDMM), or a precursor, prodrug, or acceptable salt thereof, to a subject in need thereof. The inflammation can associated with administration of an NSAID to the subject. Alternatively, the inflammatory condition can have a similar onset or presentation as NSAID induced inflammation in the GI tract.
The pharmaceutical composition can be formulated appropriately using routine and conventional aspects of the art for appropriate routes of administration. Exemplary routes of administration appropriate for the contemplated applications include intra peritoneal (IP), intravenous (IV), topical, parenteral, intradermal, transdermal, oral (e.g., via liquid or pill), and respiratory (e.g., intranasal mist) routes.
The disclosed compositions are preferably pharmaceutically acceptable and can contain pharmaceutically acceptable carriers, concentrations of salt, buffering agents, preservatives, other immune modulators, and optionally other therapeutic ingredients. The term “pharmaceutically-acceptable carrier” as used herein, means one or more compatible solid or liquid filler, dilutants or encapsulating substances which are suitable for administration to a human or other animal. The term “carrier” denotes an organic or inorganic ingredient, natural or synthetic, with which the active ingredient is combined to facilitate the application. The components of the pharmaceutical compositions also are capable of being comingled with active agents of the present invention, in a manner such that there is no interaction which would substantially impair the desired pharmaceutical efficacy.
Unless specifically defined herein, all terms used herein have the same meaning as they would to one skilled in the art of the present invention. Practitioners are particularly directed to Sambrook J., et al. (eds.) Molecular Cloning: A Laboratory Manual, 3rd ed., Cold Spring Harbor Press, Plainsview, N.Y. (2001); Ausubel F. M., et al. (eds.), Current Protocols in Molecular Biology, John Wiley & Sons, New York (2010); and Coligan J. E., et al. (eds.), Current Protocols in Immunology, John Wiley & Sons, New York (2010) for definitions and terms of art.
The use of the term “or” in the claims is used to mean “and/or” unless explicitly indicated to refer to alternatives only or the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives and “and/or.”
Following long-standing patent law, the words “a” and “an,” when used in conjunction with the word “comprising” in the claims or specification, denotes one or more, unless specifically noted.
Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like, are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to indicate, in the sense of “including, but not limited to.” Words using the singular or plural number also include the plural and singular number, respectively. Additionally, the words “herein,” “above,” and “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of the application.
Disclosed are materials, compositions, and components that can be used for, can be used in conjunction with, can be used in preparation for, or are products of the disclosed methods and compositions. It is understood that, when combinations, subsets, interactions, groups, etc., of these materials are disclosed, each of various individual and collective combinations is specifically contemplated, even though specific reference to each and every single combination and permutation of these compounds may not be explicitly disclosed. This concept applies to all aspects of this disclosure including, but not limited to, steps in the described methods. Thus, specific elements of any foregoing embodiments can be combined or substituted for elements in other embodiments. For example, if there are a variety of additional steps that can be performed, it is understood that each of these additional steps can be performed with any specific method steps or combination of method steps of the disclosed methods, and that each such combination or subset of combinations is specifically contemplated and should be considered disclosed. Additionally, it is understood that the embodiments described herein can be implemented using any suitable material such as those described elsewhere herein or as known in the art.
Publications cited herein and the subject matter for which they are cited are hereby specifically incorporated by reference in their entireties.
The following describes a study demonstrating that microbiota-derived metabolite indole decreases mucosal inflammation and injury in a murine model of NSAID enteropathy.
Non-steroidal anti-inflammatory drugs (NSAIDs) are one of the most frequently used classes of medications in the world. Unfortunately, NSAIDs induce an enteropathy associated with high morbidity and mortality. Although the pathophysiology of this condition involves the interaction of the gut epithelium, microbiota, and NSAIDs, the precise mechanisms by which microbiota influence NSAID enteropathy are unclear. It was proposed that a possible mechanism is that the microbiota may attenuate the severity of disease by specific metabolite-mediated regulation of host inflammation and injury. The microbiota-derived tryptophan-metabolite indole is abundant in the healthy mammalian gut and otherwise positively influences intestinal health. Thus the effects of indole administration on NSAID enteropathy were examined.
Mice (n=5 per group) were treated once daily for 7 days with an NSAID (indomethacin; 5 mg/kg), indole (20 mg/kg), indomethacin plus indole, or vehicle only (control). Outcomes compared among groups included: microscopic pathology; fecal calprotectin concentration; proportion of neutrophils in the spleen and mesenteric lymph nodes; fecal microbiota composition and diversity; small intestinal mucosal transcriptome; and, fecal tryptophan metabolites.
It was observed that co-administration of indole with indomethacin significantly reduced mucosal pathology scores, fecal calprotectin concentrations, and neutrophilic infiltration of the spleen and mesenteric lymph nodes induced by indomethacin. Additionally, co-administration of indole with indomethacin modulated NSAID-induced perturbation of the microbiota, fecal metabolites, and inferred metagenome. Finally, co-administration of indole with indomethacin abrogated a pro-inflammatory gene expression profile in the small intestinal mucosa induced by indomethacin.
These data demonstrate that the microbiota-derived metabolite indole attenuated multiple deleterious effects of NSAID enteropathy, including modulating inflammation mediated by innate immune responses and altering indomethacin-induced shift of the microbiota.
As described above, it was hypothesized that aspects of a healthy microbiota can prevent or ameliorate the negative side effects of NSAID administration, such as enteropathy. A mechanism by which the microbiota might influence NSAID-induced intestinal mucosal damage is by producing metabolites that protect intestinal epithelial cells. Previously, the inventors identified tryptophan metabolites, including indole, as an important class of GI microbiota-derived compounds. Indole is a quorum-sensing molecule produced by bacterial metabolism of L-tryptophan that mediates communication among bacterial population and inter-kingdom signaling between the host and microbe. Indole improves barrier function and decreases intestinal inflammation in vitro and in vivo. Moreover, several other tryptophan metabolites reportedly exert similar salutary effects on the intestinal epithelium. The inventors investigated whether indole might mitigate the severity of NSAID enteropathy. Toward this end, indole was co-administered with the NSAID indomethacin and demonstrated a reduction in severity of mucosal injury caused by indomethacin alone. To determine whether the protective effects of indole were associated with alterations in the GI microbiota, the effects of administration of NSAIDs, indole, and their co-administration on the composition and diversity of the fecal microbiota were characterized. It was observed that the co-administration of indole with indomethacin resulted in maintenance of or even an increase of an important member of the Firmicutes phylum. Finally, to better understand the mechanisms of NSAID enteropathy and the effects of indole on these processes, RNA sequencing (RNA-Seq) was performed on the distal small intestinal mucosa in mice that were untreated or treated with indomethacin, indole alone, or the combination of indomethacin and indole. Pro-inflammatory pathways associated with innate immune responses were up-regulated by indomethacin administration relative to control mice, and co-administration of indole significantly mitigated the up-regulation of these pathways concomitant with reduced GI pathology.
Calprotectin enzyme-linked immunosorbent assay (ELISA) of fecal samples collected on days 0 and 6 revealed that co-administration of indole with indomethacin significantly decreased fecal calprotectin levels (
Neutrophilic inflammation is primarily responsible for NSAID enteropathy, therefore, we quantified the abundance of neutrophils in the spleen and MLNs as measures of systemic neutrophilic response and trafficking of neutrophils though the GI tract, respectively.29-30 Indomethacin treatment resulted in a significant increase in neutrophils (defined as both CD11b- and GR-1 double-positive;
Because NSAIDs alter the intestinal microbiota, we evaluated the composition and diversity of the fecal microbiota in the four groups of mice. To adjust for uneven sequencing depth among the samples, each sample was rarefied to an even sequencing depth of 10,000 reads per sample prior to analysis. Alpha rarefaction curves and Good's coverage index estimates indicated that over 90% of the species were represented across all samples at this sequencing depth (
The primary gram-positive and gram-negative phyla found in murine feces are Firmicutes and Bacteroidetes, respectively. At the phylum level, principal component analysis (PCA) revealed a separation of NSAID-treated mice from the other groups characterized by increase in members of the phyla Bacteroidetes in the NSAID-treated animals between day 0 and day 7 (
PCA of the inferred metagenome revealed clustering and separation of the NSAID-treated mice from the other groups (
TABLES 3A-3C disclose the results of a pair-wise similarity percentage analysis (SIMPER) analysis based on the bray Curtis dissimilarity measure of fecal 16S rRNA data at the phylum level of each treatment group compared to the control group based on day 7 feces.
TABLE 3A: The first column identifies the bacterial phylum explained by that row, the second column shows % contribution of that phylum to the Bray Curtis dissimilarity measure between the 2 groups, the third column tallies the cumulative Bray Curtis dissimilarity measure thus far represented in the table, and the last 2 columns show mean abundance in control mice and mean abundance for NSAID-treated mice;
TABLE 3B: Control mice and NSAID+indole-treated mice, and
TABLE 3C: control mice and indole-treated mice.
TABLES 4A and 4B disclose the results of a pair-wise SIMPER analysis based on the Bray Curtis dissimilarity measure of fecal 16S rRNA data at the order level of NSAID and NSAID+indole groups compared to the control group based on day 7 feces.
TABLE 4A: The first column identifies the bacterial order explained by that row, the second column shows % contribution of that order to the Bray Curtis dissimilarity measure between the two groups, the third column tallies the cumulative Bray Curtis dissimilarity measure thus far represented in the table, and the last two columns show mean abundance in control mice and mean abundance for NSAID-treated mice; and
TABLE 4B: Control mice and NSAID+indole-treated mice.
TABLES 5A and 5B disclose the results of a pair-wise SIMPER analysis based on the Bray Curtis dissimilarity measure of fecal 16S rRNA data at the family level of NSAID and NSAID+indole groups compared to the control group based on day 7 feces. TABLE 5A: The first column identifies the bacterial family explained by that row, the second column shows % contribution of that family to the Bray Curtis dissimilarity measure between the 2 groups, the third column tallies the cumulative Bray Curtis dissimilarity measure thus far represented in the table, and the last 2 columns show mean abundance in control mice and mean abundance for NSAID-treated mice; and
TABLE 5B: Control mice and NSAID+indole-treated mice.
TABLE 6 discloses the results of a pair-wise SIMPER analysis based on the Bray Curtis dissimilarity measure of the inferred metagenome of the fecal microbiota of NSAID and NSAID+indole groups compared to the control group based on day 7 feces. The first column identifies the KEGG pathway explained by that row, the second column shows % contribution of that pathway to the Bray Curtis dissimilarity measure between the 2 groups, the third column tallies the cumulative Bray Curtis dissimilarity measure thus far represented in the table, and the last 4 columns show mean abundance in control mice and mean abundance for NSAID-treated mice, direction of change for that comparison, NSAID+indole-treated mice and directional change for that comparison versus control mice.
Multiple tryptophan-derived metabolites produced by the microbiota predicted to be bioactive and exert effects on the host have been identified (Sridharan G V, Choi K, Klemashevich C, Wu C, Prabakaran D, Pan L B, Steinmeyer S, Mueller C, Yousofshahi M, Alaniz R C, et al. Prediction and quantification of bioactive microbiota metabolites in the mouse gut. Nature Communications 2014; 5:5492, incorporated herein by reference in its entirety). Given the importance of the microbiota in NSAID enteropathy, the effects of indole on the intestinal epithelium and microbiota were examined (
TABLE 7 discloses a correlation of fecal tryptophan metabolites with histopathology scores≤2 or>2. Only the tryptophan metabolite tyramine correlated with microscopic pathology score.
RNA sequencing (RNA-Seq) of the distal small intestinal mucosa was performed to examine the in vivo transcriptomic changes associated with NSAID enteropathy and to gain insight into how the co-administration of indole altered gene expression. The top genes that were significantly up- or down-regulated (fold change≥2) in NSAID-treated mice relative to control mice, indole-treated mice relative to control mice, and NSAID+indole-treated mice relative to control mice were tabulated. The Ingenuity Pathway Analysis software package was used to identify pathways represented by differentially expressed genes. Several canonical pathways were altered in NSAID-treated mice relative to controls (
Moreover, transcription of specific pro-inflammatory cytokines (interleukin [IL]-1α, IL-1β, tumor necrosis factor (TNF), IL-6) and chemokines (chemokine C-X-C motif [CXC]L1, CXCL3, CXCL2, CXCL5, CCL2, CCL7) was significantly up-regulated in NSAID-treated mice; however, when indole was co-administered the degree of up-regulation was not significantly different than control mice (
It was also observed that the exfoliated intestinal epithelial cells (IEC) and tissue-level gene expression profiles were similar (not shown). Thus, the differences in the exfoliated IEC transcriptome between control versus indomethacin-treated animals and control versus indole+indomethacin-treated animals were examined. For this purpose, the top 40 canonical pathways altered in exfoliated IECs were sorted based on differences in Z-scores between the 2 treatments (
Co-administration of indole attenuated small intestinal mucosal damage induced by administration of indomethacin in mice as manifested by reduced microscopic pathology and fecal calprotectin concentration. Fecal calprotectin is a well-established, non-invasive indicator of intestinal mucosal injury induced by NSAIDs in human patients and animal models, and correlates well with 4-day fecal excretion of 111Indium-labelled leukocytes. The findings of decreased fecal calprotectin and decreased microscopic pathology have important clinical implications. A variety of NSAIDs are used widely for an array of clinical conditions ranging from pain relief for minor injuries to management of rheumatoid arthritis or cancer. The relatively low cost, high effectiveness, and lack of alternatives to NSAIDs indicate that their use will continue to be highly prevalent. Consequently, agents that might be co-administered with NSAIDs to diminish NSAID enteropathy would be clinically important. Further evaluation of indole to ameliorate NSAID enteropathy in animal models and naturally occurring disease is warranted by our findings.
Administration of NSAIDs increases the proportion of gram-negative organisms at the expense of gram-positive organisms in the intestinal microbiota, and this shift has been shown to contribute to NSAID-induced intestinal injury. Specifically, NSAID administration decreases various members of the class Clostridia and increases members of the class Bacteroidia. Mice treated with indole and indomethacin did not have a change in the abundance of Bacteroidia but did have an increase in several members of the gram-positive family Clostridiales in concert with diminution of the severity of intestinal mucosal damage. Evidence exists that the microbiota plays an important role in the development of NSAID enteropathy. Germ-free rats treated with NSAIDs develop less severe enteropathy than specific-pathogen-free rats or germ-free rats that have been colonized with gram-negative bacteria.39 Toll-like receptor (TLR) 4-deficient mice develop less severe lesions than isogeneic TLR4-competent strains. Dramatic NSAID-induced alterations of the gut microbiota are well-documented and most often characterized by a loss of gram-positive bacteria with a concurrent increase in gram-negative bacteria. Moreover, this particular shift in the microbiota has been associated with increased severity of intestinal mucosal injury, and preventing this shift can reduce mucosal injury. The classic indomethacin-induced increase in types of Bacteroidia we observed in our study were not significant, but this was likely attributable to limited power to detect a statistically significant difference resulting from our small sample size. It is not clear why increased abundance of gram-negative bacteria worsens the severity of NSAID enteropathy, but direct effects of LPS and the host innate immune response to LPS appear to be important. It is also possible that loss of beneficial gram-positive bacteria is important. Commensal Clostridia have been shown to be critically important in gut homeostasis, specifically members of Clostridium cluster XIVa and Clostridium cluster IV. Interestingly, several members of these two clostridial clusters were increased in the NSAID-treated animals in which indole was co-administered.
The host response to the microbiota might be more important than the microbiota itself in the pathogenesis of NSAID enteropathy. Neutrophils are key effector cells of innate immunity and are critically important in the pathogenesis of NSAID enteropathy. Neutrophils are recruited to the site of injury by the influx of luminal contents following increased mucosal permeability. The resident innate immune cells present in the epithelium and lamina propria release cytokines and chemokines that attract circulating neutrophils. These neutrophils, along with other innate immune cells, then release pro-inflammatory cytokines, typically characterized by an abundance of the IL-1 super family, TNF-α, IL-6, and others, that are responsible for the damage to the lower GI tract. This critical role for neutrophils in NSAID enteropathy is supported by our findings of neutrophilic infiltration of both the spleen and MLN following NSAID administration and reduced neutrophil concentrations in these tissues with co-administration of indole. These data also affirm the importance of the innate immune response in the pathophysiology of NSAID enteropathy because many of the most up-regulated pathways identified by RNA-Seq reflected the innate immune response (viz., NF-κB pathway, TLR signaling pathways, and the LPS/IL-1 response). Moreover, at the individual gene level, several of the classic pro-inflammatory cytokines associated with neutrophil activation and known to be important in NSAID enteropathy (e.g., TNF-α, IL-1, and IL-6) were up-regulated among NSAID-treated mice. Co-administration of indole, however, attenuated or reversed up-regulation of genes associated with innate immunity and inflammation that contribute to the pathogenesis of NSAID enteropathy. In addition, several chemokines that attract neutrophils were up-regulated in the NSAID-treated mice and this up-regulation was dramatically attenuated by the co-administration of indole. These data indicate that indole can mitigate the host innate immune response to the influx of luminal contents across injured epithelia. Indole has been shown to inhibit nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling in intestinal epithelial cells. It is thus plausible that indole exerts similar effects on neutrophils and other innate immune cells, thereby reducing cytokines dependent upon NF-κB signaling. Although NF-κB signaling was activated by administration of both NSAID and NSAID+indole, activation of this pathway was greatly diminished by co-administration of indole with NSAIDs, suggesting indole might mitigate NSAID damage in part by inhibiting NF-κB. It is important to note that the mRNA for RNA-seq was isolated from mucosal scrapings. These scrapings likely contain epithelial cells as well as cells residing in the lamina propria (i.e., immune cells recruited to the inflamed gut due to loss of barrier function) and therefore we cannot be sure the exact source of gene expression profiles. NSAID enteropathy is characterized as a mucosal injury and we felt examining the transcriptome of this location would be more informative than examining the transcriptome of whole tissue. The observed anti-inflammatory effects of indole may be due to indole's effects on epithelial cells, immune cells in the lamina propria, or both.
It is unclear how indole prevented the characteristic shifts in the composition of the microbiota associated with NSAID administration. Indole has long been recognized as a quorum-sensing molecule so it is possible that indole directly affected the microbial community by acting as an intra-kingdom signaling molecule. It is, however, also plausible that changes in the microbiota associated with NSAID use occur secondary to mucosal inflammation because mucosal inflammation has been shown to alter the luminal environment. Indole might have attenuated mucosal damage, which in turn prevented the expected changes in the microbiota. Finally, it has been shown that GI microbiota can vary with environment including cage-dependent variation and cage-dependent clustering. In order to mitigate this phenomenon, after acclimation and immediately prior to starting the study (Day 0), mice were randomly assigned into treatment groups and then were moved into cages based on the group to which they were randomly assigned. There were no significant differences in the fecal beta diversity among the groups at Day 0. It is possible, however, that were some cage-dependent microbiota changes that occurred over the 7 days of treatment that might have influenced the composition of the microbiota after treatment.
Indole is present in the GI tract of humans and animals at relatively high concentrations (˜250-1,100 μM). It has been speculated that, because intestinal epithelial cells are continually exposed to indole, indole may act as an interkingdom signaling molecule. Indeed the inventors have shown, in vitro, that indole does behave in this manner and has anti-inflammatory effects on intestinal epithelial cells and upregulates expression of genes associated with tight cell junctions. It was tested, then, whether increasing the concentration of indole within the lumen of the GI tract might mitigate NSAID enteropathy because of the in vitro effects of indole on intestinal epithelial cells. As expected, mice gavaged with indole (alone or in combination with indomethacin) were observed to have increased fecal concentration of indole. Interestingly, the NSAID-only treated mice also had increased fecal concentrations of indole. Although both gram-negative and gram-positive bacteria produce indole, the list of gram-negative bacteria known to produce indole is much larger than gram-positive bacteria. Thus, the observed increase in gram-negative bacteria in the NSAID treated mice might explain their increased fecal concentrations of indole. The beneficial effects of indole in this study were observed at the distal small intestine, but the concentration of indole and the microbiota diversity were determined using fecal samples. Fecal metabolite and microbiota characterization do not always correlate well with those of more proximal mucosal locations in the GI tract. Therefore, it is possible that indole was present in higher concentrations in the distal small intestine of mice treated with NSAID combined with indole compared with mice treated with the NSAID alone, thus contributing to the attenuation of NSAID-induced injury by indole administration. Interestingly, several tryptophan metabolites that act as neurotransmitters including serotonin and 5-hydroxytryptamine were also increased in NSAID-treated mice. Hypermotility of the GI tract is induced by NSAIDs and contributes to the pathophysiology of NSAID enteropathy. The microbiota shift induced by NSAIDs might result in production of prokinetic metabolites that contribute to GI hypermotility.
In summary, indole supplementation of mice attenuates the deleterious effects of NSAIDs on the distal small intestine and modulates NSAID-induced alterations in the composition of the fecal microbiota. The major events in the onset of NSAID enteropathy are intestinal epithelial cell death, increased mucosal permeability, influx of luminal contents, and host innate immune response to the microbiota. Indole likely reduces intestinal injury induced by NSAIDs at multiple levels, including neutrophilic infiltration, NSAID-induced dysbiosis, and pro-inflammatory pathways in the distal small intestine. Future work will focus on interrogating the potential mechanisms by which indole exerts this beneficial effect in order to further elucidate means to control or prevent NSAID enteropathy.
Animal protocols were approved by the Texas A & M Institutional Animal Care and Use Committee in accordance with appropriate institutional and regulatory bodies' guidelines.
Eight- to 10-week-old specific-pathogen-free C57BL/6J mice were purchased and allowed to acclimate for 2 weeks. Mice were fed standardized laboratory rodent diet and sterile water ad libitum. Mice were randomly divided into the following 4 groups (n=5 mice/group): 1) NSAID (indomethacin); 2) indole; 3) NSAID+indole; and, 4) untreated controls. Mice were then rehoused on the basis of treatment group assignment, with 5 animals/group-cage. To induce NSAID enteropathy, mice in group 1 were gavaged once daily with indomethacin (5 mg/kg; for 7 days; Sigma Aldrich, St. Louis, Mo.) dissolved in dimethylysulfoxide (DMSO) (Sigma Aldrich, St. Louis, Mo.) and further diluted in phosphate buffered saline (PBS). Mice in group 2 received indole by gavage (20 mg/kg; once daily for 7 days; Sigma Aldrich, St. Louis, Mo.) dissolved in sterile water warmed to 55° C. Mice in group 3 received indole co-administered with indomethacin by gavage at the dosages described above. All mice were gavaged with equal volumes (200 μL) and equal concentrations of DMSO (0.001%).
Feces were collected daily by placing individual animals in sterile plastic cups that were RNase- and DNase-free until they passed feces. The mice were immediately returned to their home cages and the feces immediately flash frozen at −80° C. All animals were euthanized via CO2 asphyxiation on day 8 (i.e., after 7 days of treatment). The small intestine was harvested, opened longitudinally, rinsed with ice-cold PBS, and the distal ⅓ of the intestinal mucosa was scraped for tissue gene expression analysis. The remaining small intestine was fixed in 4% paraformaldehyde, Swiss-rolled, paraffin-embedded, and stained with hematoxylin and eosin. The spleen and mesenteric lymph nodes (MLN) were harvested, and immediately placed in ice cold RPMI-1640-c+10% fetal calf serum (FCS: Life Technologies, Carlsbad, Calif.), homogenized, and prepared as a single cell suspension for flow cytometric analysis as previously described (Wang N, Strugnell R, Wijburg O, Brodnicki T. Measuring bacterial load and immune responses in mice infected with Listeria monocytogenes. Journal of Visualized Experiments: JoVE 2011).
A murine calprotectin ELISA kit (HK214, Hycult Biotech, Plymouth Meeting, Pa.) was used according to the manufacturer's protocol with slight modifications. Briefly, 100 mg of feces was homogenized in extraction buffer (0.1 M Tris, 0.15 M NaCl, 1.0 M urea, 10 mM CaCl2, 0.1 M citric acid monohydrate, 5 g/l bovine serum albumin (BSA) and 0.25 mM thimerosal [pH 8.0]). The homogenate was centrifuged at 10,000×g at 4° C. for 20 minutes and the supernatant used as directed in manufacturer's protocol.
RNA was extracted from the mucosal scrapings using an RNeasy mini kit (QIAGEN, Redwood City, Calif.) following the manufacturer's instructions and including on-column DNase treatment. RNA quantity was determined using a Nanodrop spectrophotometer (Fisher Thermoscientific) and the quality was assessed using the Nano6000 chip on a Bioanalyzer 2100(Agilent Technologies). Only RNA with an integrity number (RIN)≥8 was used. The samples were randomized before beginning the RNA-Seq library preparation. Sequencing libraries were made using 250 ng of RNA and the TruSeq RNA Sample Preparation kit (Illumina) following the manufacturer's instructions. A volume of 2.5 μl of ERCC spike-in RNA control mix (Life Technologies) was added to the starting RNA at a dilution of 1:1000. The libraries were pooled and sequenced on an Illumina HiSeq 2500 at the Texas AgriLife Genomics and Bioinformatics Services Core Facility (College Station, Tex.). Sequencing data were provided in a de-multiplexed format and aligned using Spliced Transcripts Alignment to a Reference (STAR) software with default parameters and referenced against the genome of Mus musculus (Ensembl version GRCm38) (Dobin A, Davis C A, Schlesinger F, Drenkow J, Zaleski C, Jha S, Batut P, Chaisson M, Gingeras T R. STAR: ultrafast universal RNA-seq aligner. Bioinformatics (Oxford, England) 2013; 29:15-21). Differentially expressed genes were determined using EdgeR based on the matrix of gene counts (Robinson M D, McCarthy D J, Smyth G K. edgeR: a Bioconductor package for differential expression analysis of digital gene expression data. Bioinformatics (Oxford, England) 2010; 26:139-40). Gene lists were analyzed through use of QIAGEN's Ingenuity® Pathway Analysis (IPA, QIAGEN, Redwood City, Calif. http://www.qiagen.com/ingenuity). Sequence data were uploaded into NCBI small reads archive (Accession number PRJNA290483).
Microbiota 16S rRNA gene sequencing methods were adapted from the methods developed for the NIH-Human Microbiome Project (A framework for human microbiome research. Nature 2012; 486:215-21; Structure, function and diversity of the healthy human microbiome. Nature 2012; 486:207-14). Briefly, bacterial genomic DNA was extracted using MO BIO PowerSoil DNA Isolation Kit (MO BIO Laboratories) according to the manufacturer's protocol. The 16S rDNA V4 region was amplified by PCR and sequenced in the MiSeq platform (Illumina) using the 2×250-bp paired-end protocol yielding paired-end reads that overlap almost completely (Caporaso J G, Lauber C L, Walters W A, Berg-Lyons D, Huntley J, Fierer N, Owens S M, Betley J, Fraser L, Bauer M, et al. Ultra-high-throughput microbial community analysis on the Illumina HiSeq and MiSeq platforms. The ISME Journal 2012; 6:1621-4). The primers used for amplification contain adapters for MiSeq sequencing and dual-index barcodes so that the PCR products can be pooled and sequenced directly. The software suite Quantitative Insights Into Microbial Ecology (QIIME v1.9[http://qiime.sourceforge.net]) was used for data processing and analysis (Caporaso J G, Kuczynski J, Stombaugh J, Bittinger K, Bushman F D, Costello E K, Fierer N, Pena A G, Goodrich J K, Gordon J I, et al. QIIME allows analysis of high-throughput community sequencing data. Nature Methods 2010; 7:335-6). The raw sequence data were de-multiplexed, and low-quality reads were filtered using the database's default parameters. Chimeric sequences were detected using Uchime and removed prior to further analysis.64 Sequences were then assigned to operational taxonomic units (OTUs) using an open-reference OTU picking protocol [http://qiime.org/scripts/pick_open_reference_otus.html] with UCLUST software in QIIME based on 97% identity with the Greengenes database (v13_5) (Edgar R C. Search and clustering orders of magnitude faster than BLAST. Bioinformatics (Oxford, England) 2010; 26:2460-1; DeSantis T Z, Hugenholtz P, Larsen N, Rojas M, Brodie E L, Keller K, Huber T, Dalevi D, Hu P, Andersen G L. Greengenes, a chimera-checked 16S rRNA gene database and workbench compatible with ARB. Applied and Environmental Microbiology 2006; 72:5069-72; McDonald D, Price M N, Goodrich J, Nawrocki E P, DeSantis T Z, Probst A, Andersen G L, Knight R, Hugenholtz P. An improved Greengenes taxonomy with explicit ranks for ecological and evolutionary analyses of bacteria and archaea. The ISMS Journal 2012; 6:610-8). To adjust for uneven sequencing depth among the samples, each sample was rarefied to an even sequencing depth (10,512 reads/sample) prior to further analysis.
Alpha rarefaction, beta diversity measures, richness, taxonomic summaries, and tests for significance were calculated and plotted using QIIME. The weighted and unweighted Unifrac distances were calculated for comparison of beta diversity. Differences in microbial communities among the treatment groups were investigated by visual assessment of clustering on principal component analysis (PCA) and by analysis of similarity (ANOSIM) calculated on unweighted UniFrac distance metrics (Clark K. Non-parametric multivariate analyses of changes in community structure. Australian Journal of Ecology 1993; 18:117-43; Lozupone C, Knight R. UniFrac: a new phylogenetic method for comparing microbial communities. Applied and Environmental Microbiology 2005; 71:8228-35; Bray J R, Curtis J T. An ordination of upland forest communities of southern Wisconsin. Ecological Monographs 1957:325-49). ANOSIM is a non-parametric test of difference between 2 or more groups based on a distance metric. This test gives an R value between −1 and 1 where large positive R values indicate a large magnitude of dissimilarity between the groups and small R values indicate small magnitudes of dissimilarity; the P value provides statistical significance (Clark K. Non-parametric multivariate analyses of changes in community structure. Australian Journal of Ecology 1993; 18:117-43). When ANOSIM identified significant differences among groups, then pairwise ANOSIM was performed to determine which groups differed significantly and similarity percentage (SIMPER) was used to examine which features contributed to the differences among groups. ANOSIM, SIMPER, and PCA plots were performed with PAST v3.05 (Hammer O, Harper D, Ryan P D. PAST: Paleon Statictics Software Package for Education and Data Analysis. Palaeontologica Electronica 2001; 4:9).
The software Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) was used to predict the metagenome (Langille M G, Zaneveld J, Caporaso J G, McDonald D, Knights D, Reyes J A, Clemente J C, Burkepile D E, Vega Thurber R L, Knight R, et al. Predictive functional profiling of microbial communities using 16S rRNA marker gene sequences. Nature Biotechnology 2013; 31:814-21). Sequencing data were prepared as described above, but sequences were then clustered into OTUs using a closed-reference OTU picking protocol at the 97% sequencing identity level [http://qiime.org/scripts/pick_closed_reference_otus.html]. The resulting OTU table was normalized by the expected copy number(s) of the 16s rRNA gene in each OTU. PICRUSt was then used to predict the metagenome [https://picrust.github.io/picrust/tutorials/metagenome_prediction.html#metagenome-prediction-tutorial]. Each sample was rarefied to an even sequencing depth to adjust for uneven sequencing depth prior to further analysis. Differences in the metagenomes among the groups were investigated by visual assessment of clustering on PCA and by analysis of similarity (ANOSIM) calculated on Bray Curtis dissimilarity metric.
Metabolites from the fecal contents were extracted using a solvent-based method as previously described (Sridharan G V, Choi K, Klemashevich C, Wu C, Prabakaran D, Pan L B, Steinmeyer S, Mueller C, Yousofshahi M, Alaniz R C, et al. Prediction and quantification of bioactive microbiota metabolites in the mouse gut. Nature Communications 2014; 5:5492). Briefly, fecal pellets were homogenized using a homogenizer (Omni International) with equal volume of cold methanol and half volume of chloroform. The samples were then centrifuged at 10,000 g at 4° C. (Thermo Fisher Scientific) for 10 min. Supernatant was passed through a 70-μm sterile nylon cell strainer (Falcon) and 0.6 ml of ice cold water was added. The samples were vortex and centrifuged again at 10,000 g for 5 minutes. The upper phase and lower phase were collected and 400 μl of upper phase was dried to a pellet using a vacufuge (Eppendorf, Hauppauge, N.Y.), and then reconstituted in 50 μl of methanol/water (1:1, v/v). The samples were stored at −80° C. until analysis. Tryptophan metabolites in the samples were detected and quantified on a triple quadrupole linear ion trap mass spectrometer (3200 QTRAP, AB SCIEX, Foster City, Calif.) coupled to a binary pump HPLC (Prominence LC-20, Shimazu, Concord, Ontario, Canada).
Spleens and MLNs were processed individually to single-cell suspensions with frosted glass slides in RPMI-c+10% FCS, and spleen cells underwent red blood cell lysis (Charles N, Hardwick D, Daugas E, Illei G G, Rivera J. Basophils and the T helper 2 environment can promote the development of lupus nephritis. Nature Medicine 2010; 16:701-7). Cell suspensions were plated in individual wells, washed with 0.5% BSA in PBS, surface-stained for CD11b-AlexaFluor488 (eBioscience cat. #53-0112-82) and Gr-1-biotin (BD cat. #553125), followed by streptavidin-PE (eBioscience cat. #12-4317), fixed with 0.4% paraformaldehyde, and samples were acquired on a BD FACS Aria II in the College of Medicine Cell Analysis Facility (COM-CAF) at the Texas A & M Health Science Center.
The stained sections of the small intestine were analyzed by a board-certified veterinary pathologist (BRW) blinded to treatment group. The slides were scored as previously described for intestinal inflammation (Jia Q, Lupton J R, Smith R, Weeks B R, Callaway E, Davidson L A, Kim W, Fan Y Y, Yang P, Newman R A, et al. Reduced colitis-associated colon cancer in Fat-1 (n-3 fatty acid desaturase) transgenic mice. Cancer Research 2008; 68:3985-91). Briefly, mucosal injury was determined by the following parameters scored from 0 (no evidence) to 3 (marked): mucosal ulceration, mucosal erosion, and presence of squamified epithelium. Inflammatory changes were scored similarly based on the following parameters: lymphocytic infiltration, plasma cell infiltration, and neutrophilic infiltration. Finally, an overall evidence of injury score was used to document total injury graded from 0 (none) to 4 (marked). Morphological parameters were obtained from digitally scanned slides using SPOT vr 5.0 software. Three sets of measurements from 3 separate sections were recorded for each animal by an observer blinded to treatment group. Measurements consisted of villus height, crypt depth, and submucosal mural thickness. The ratio of the villus height to crypt depth was calculated (
Results were expressed as mean±95% confidence interval unless indicated otherwise. For all analyses, significance was set P≤0.05. Data were analyzed using S-PLUS statistical software (Version 8.2, TIBCO Inc., Seattle, Wash.) unless otherwise noted. Histology scores, the proportion of neutrophils in the spleen and MLNs, ratios of villus height to crypt depth, submucosal thicknesses, paired differences between Day 7 and Day 0 in phyla and families, and fecal tryptophan metabolites were compared among treatment groups using a generalized linear model with post hoc testing for pairwise differences among groups using the method of Sidak (Šidák Z K. Rectangular confidence regions for the means of multivariate normal distributions. J Am Stat Assoc 1967; 62:626-33). To meet statistical assumptions underlying the generalized linear model, the histology scores were converted to ranks and the neutrophil data were log10 transformed prior to analysis. Ratios of villus height to crypt depth and submucosal thicknesses were compared among groups using a generalized linear model with post hoc testing for pairwise differences among groups using the method of Sidak. Fecal calprotectin concentrations were analyzed as a function of treatment group, time (Day 0 [baseline] and Day 7), and their interaction using linear mixed-effects modeling with treatment group and time modeled as fixed, categorical effects and individual mouse modeled as a random effect to account for repeated measures on individual mice. Paired differences between Day 0 and Day 7 in phyla and families were compared among groups using a generalized linear model and post hoc testing for pairwise differences among groups using the method of Sidak.
While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.
This application claims the benefit of Provisional Application No. 62/310,606, filed Mar. 18, 2016, Provisional Application No. 62/310,648, filed Mar. 18, 2016, Provisional Application No. 62/310,643, filed Mar. 18, 2016, and Provisional Application No. 62/310,630, filed Mar. 18, 2016, each of which is expressly incorporated herein by reference in its entirety.
This invention was made with Government support under GM106251 awarded by The National Institutes of Health, National Institute of General Medical Sciences; AI110642 awarded by The National Institutes of Health, National Institute of Allergy and Infectious Disease; A095788 awarded by The National Institutes of Health, National Institute of Allergy and Infectious Disease; and MCB-1120827, awarded by the National Science Foundation. The Government has certain rights in the invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US17/23011 | 3/17/2017 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62310630 | Mar 2016 | US | |
| 62310606 | Mar 2016 | US | |
| 62310643 | Mar 2016 | US | |
| 62310648 | Mar 2016 | US |
