Patent Application
20130005602
The present invention relates to a method for evaluating the sensitizing potential of a test compound and a kit for implementing said method.
The perfume, cosmetics and pharmacy industries must remain competitive and effective and continue to regularly offer new products, with the constraint of complying with the human and environmental safety standards attached to their use. Contact allergy is one of the major risks associated with the use of such products.
Cutaneous contact allergy (or atopic dermatitis) is a major public health problem in humans. It represents a serious and restrictive environmental immunotoxic event, whose effects must be anticipated when marketing products that could induce it. Skin sensitization and, consequently, the associated allergic manifestation, is the result first of an interaction of an allergenic molecule with specialized epidermal cells, antigen-presenting cells (Langerhans cells, dendritic cells) and then, second, their presentation by these cells to CD4+ and CD8+ effector T cells. These T cells are the basis of the allergic and inflammatory reaction. However, the allergens, especially those that can be present in a fragrance, are small molecules that cannot be recognized directly. To be recognized, they must be associated beforehand with self proteins. Thus, it is the newly-formed heterodimeric complex in the skin that will finally be presented to T cells in the proximal lymph nodes. Accordingly, the ability of a chemical molecule (fragrance compound or cosmetic ingredient) to be associated with a protein of the user of this product is a prerequisite for the induction of the consecutive pathological skin reaction. This pathological skin reaction could be irritation, sensitization, or in the majority of cases, both irritation and sensitization.
Irritation is a reversible inflammatory reaction in living tissues by chemical action at the contact site. This is recognized by edema consecutive to the influx of fluid to the tissues, redness, heat and/or pain. In response to a chemical attack, keratinocytes of the epidermis and fibroblasts of the dermis are stimulated and release cytokines IL1, TNF alpha, IL6 and IL8, as well as mediators such as prostaglandins (PGE2) into the skin which will initiate the inflammatory response.
The delayed and immediate hypersensitivities that are the basis of sensitization involve the concept of “memory” which emphasizes their irreversible nature, unlike irritation. In this case as well, the mechanisms occur in two phases:
Thus, although from a histological point of view, sensitizing and irritant contact dermatitis are very similar, the immunological consequences analyzed at the cellular level are not necessarily similar. Consequently, it is important to have reliable methodologies for distinguishing them. An original predictive approach is even more necessary since currently no clear correlation has been demonstrated between a given molecular structure and allergenicity in the broadest sense of term.
So far, animals have been used to identify skin sensitizing molecules and the LLNA (local lymph node assay), based on the induced proliferation of lymph node lymphocytes after contact with the sensitizer, has been developed. This test was adopted as “Testing guideline 429” by the Organization for Economic Cooperation and Development (OECD) and is still considered as the standard test for determination of a sensitizing chemical agent.
The new European restrictions now require the use of methods that do not use animals and it is therefore vital to develop alternative methods for determining if a new composition or new product is likely to represent a risk for humans due to its sensitizing properties.
The Inventors have shown that in vivo recognition of a substance does not occur at the draining lymph node, as is generally accepted, but rather at the tissue where the substance comes into contact with the body, the skin in the present case. This would explain why some substances are sensitizing in one tissue and not in another, as is often observed. It therefore appears that it is the reaction in skin tissue that sends the message to the allergen-presenting cells: the dendritic cells will then transmit it to the T cells in the draining lymph node.
It is generally accepted that skin models are not sufficient to analyze sensitizing responses and it is necessary to have dendritic cells (EP 0857971).
The Inventors have now demonstrated that skin constitutes a sufficient model to show specific biomarkers for sensitization and/or irritation in humans and in mice, and that it is not necessary to add other types of cells if the identified genes are analyzed at a specific time. The EPISKIN model can thus be the standard tissue for evaluating the sensitizing nature of a test compound.
Moreover, the Inventors have shown that it was not sufficient to show an overexpression of only one of said biomarkers to conclude the sensitizing potential of a test compound, and that only studying at least six specific markers for sensitization would allow drawing conclusions about the sensitizing potential of a test compound.
Thus, the present invention relates to a method for evaluating the sensitizing potential of a test compound, comprising the steps of:
a) contacting a test compound with a biological sample;
b) determining the expression level of at least six genes chosen in the group consisting of: BRAK (CXC chemokine ligand 14), CTSS (cathepsin S), DAPK2 (death-associated protein kinase 2), FABP4 (fatty acid binding protein 4), HSP27 (heat shock 27 kDa protein), IL18 (Interleukin-18), HSP90 (heat shock 90 kDa protein), IL1R2 (interleukin-1 receptor type II), TPSAB1 (tryptase alpha/beta 1), CXCR1 (interleukin 8 receptor, alpha), DEFB1 (defensin, beta 1), DHFR (dihydrofolate reductase), EHF (ets homologous factor), IVL (involucrin) KRT4 (keratin 4), MELANA (melan-A), NGAL (gelatinase-associated lipocalin), PDZK1IP1 (PDZK1 interacting protein interaction 1), PI3 (peptidase inhibitor 3), PSME2 (proteasome activator subunit 2), SERPINB3 (serpin peptidase inhibitor member 3), AKR1B10 (aldo-keto reductase family 1, member B10), AKR1C1 (aldo-keto reductase family 1, member C1), AKR1C2 (aldo-keto reductase family 1, member C2), CYP1B1 (cytochrome P450, family 1, subfamily B, polypeptide 1), FTH1P (ferritin, heavy polypeptide 1), FTL (ferritin, light polypeptide 1), G6PD (glucose-6-phosphate dehydrogenase), GCLM (glutamate-cysteine ligase modifier subunit), NQO2 (NAD(P)H dehydrogenase, quinone 2), SLC7A11 (solute carrier family 7, Member 11), TXNRD1 (thioredoxin reductase 1), UGT1A1 (UDP glucuronosyltransferase 1 family, polypeptide A1), UGT1A9 (UDP glucuronosyltransferase 1 family, polypeptide A9, YWHAZ (tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide), CD36 (CD36 molecule), CYP1A1 (cytochrome P450, family 1, subfamily A, polypeptide 1), GCLC (glutamate-cysteine ligase, catalytic subunit), HMOX1 (heme oxygenase 1), NQ01 (NAD(P)H dehydrogenase, quinone 1) and S100A8 (S100 calcium binding protein A8).
Preferably, said at least six genes are chosen in the group consisting of: BRAK (CXC chemokine ligand 14), CTSS (cathepsin S), DAPK2 (death-associated protein kinase 2), FABP4 (fatty acid binding protein 4), HSP27 (heat shock 27 kDa protein), IL18 (IL-18), HSP90 (heat shock 90 kDa protein), IL1R2 (interleukin-1 receptor type II), TPSAB1 (tryptase alpha/beta 1), CXCR1 (interleukin 8 receptor, alpha), DEFB1 (defensin, beta 1), DHFR (dihydrofolate reductase), EHF (ets homologous factor), IVL (involucrin) KRT4 (keratin 4), MELANA (melan-A), NGAL (gelatinase associated lipocalin), PDZK1IP1 (PDZK1 interacting protein interaction 1), P13 (peptidase inhibitor 3), PSME2 (proteasome activator subunit 2), SERPINB3 (serpin peptidase inhibitor member 3), AKR1B10 (aldo-keto reductase family 1, member B10), AKR1C1 (aldo-keto reductase family 1, member C1), AKR1C2 (aldo-keto reductase family 1, member C2), CYP1B1 (cytochrome P450, family 1, subfamily B, polypeptide 1), FTH1P (ferritin, heavy polypeptide 1), FTL (ferritin, light polypeptide 1), G6PD (glucose-6-phosphate dehydrogenase), GCLM (glutamate-cysteine ligase modifier subunit), NQO2 (NAD(P)H dehydrogenase, quinone 2), SLC7A11 (solute carrier family 7, Member 11), TXNRD1 (thioredoxin reductase 1), UGT1A1 (UDP glucuronosyltransferase 1 family, polypeptide A1), UGT1A9 (UDP glucuronosyltransferase 1 family, polypeptide A9) and YWHAZ (tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide),
more preferentially still chosen in the group consisting of: BRAK (CXC chemokine ligand 14), CTSS (cathepsin S), DAPK2 (death-associated protein kinase 2), FABP4 (fatty acid binding protein 4), HSP27 (heat shock 27 kDa protein), IL18 (IL-18), HSP90 (heat shock 90 kDa protein), IL1R2 (interleukin-1 receptor type II), TPSAB1 (tryptase alpha/beta 1), CXCR1 (interleukin 8 receptor, alpha), DEFB1 (defensin, beta 1), DHFR (dihydrofolate reductase), EHF (ets homologous factor), IVL (involucrin) KRT4 (keratin 4), MELANA (melan-A), NGAL (gelatinase associated lipocalin), PDZK1IP1 (PDZK1 interacting protein interaction 1), P13 (peptidase inhibitor 3 and SERPINB3 (serpin peptidase inhibitor member 3),
and even more preferentially still chosen in the group consisting of: BRAK (CXC chemokine ligand 14), CTSS (cathepsin S), DAPK2 (death-associated protein kinase 2), FABP4 (fatty acid binding protein 4), HSP27 (heat shock 27 kDa protein) IL18 (IL-18), HSP90 (heat shock 90 kDa protein), IL1R2 (interleukin-1 receptor type II), TPSAB1 (tryptase alpha/beta 1), or in the group made up of: CXCR1 (interleukin 8 receptor, alpha), DEFB1 (defensin, beta 1), DHFR (dihydrofolate reductase), EHF (ets homologous factor), IVL (involucrin) KRT4 (keratin 4), MELANA (melan-A), NGAL (lipocalin 2), PDZK1IP1 (PDZK1 interacting protein interaction 1), PI3 (peptidase inhibitor 3, PSME2 (proteasome activator subunit 2) and SERPINB3 (serpin peptidase inhibitor member 3)
Preferably, the method according to the present invention can also comprise another step c) for determining the sensitizing potential of a test compound.
Preferentially, said step c) can consist of a step of selecting said compound as presenting a sensitizing potential if the expression level of at least 6 of said genes is above a threshold value.
Preferably, the method according to the present invention is an in vitro method. As used here, the term “biological sample” refers to any solid or liquid sample from a subject.
Preferably, said biological sample is a skin sample.
In a particularly preferred manner, the skin sample is a skin sample reconstructed in vitro, such as, for example, the EpiSkin (EPISKIN, Lyon France), EpiDerm™ (MATEK Corporation, Ashland, Mass.) or SkinEthic™ RHE (SKINETHIC, Nice, France) model. Preferably, said skin sample reconstructed in vitro also comprises a keratin layer.
Even more preferably, the skin sample does not comprise other types of additional cells, and more preferentially no additional Langerhans cells.
The test compound can be a compound of various type, structure and origin, especially a biological compound, chemical compound, synthetic, etc.
The test compound can be any product present in the isolated form or mixed with other products. The test compound can be defined in terms of structure and/or composition or can be defined functionally. The test compound can be, for example, an isolated and structurally defined product, an isolated product of undefined structure, a mixture of known and characterized products or a composition comprising one or more products. One or more compounds can be tested in this way, mixed or separately.
Such compositions can be, for example, samples of a cosmetic or dermatological product.
Preferably, said test compound is suitable for use on the skin and may be used in a cosmetic or dermatological composition.
Preferentially, said method allows assessing the sensitizing potential of a test compound in humans, comprising a step b) of determining the expression level of at least six genes such as defined in Table 1, and preferably chosen in the group made up of: CXCR1 (interleukin 8 receptor, alpha), DEFB1 (defensin, beta 1), DHFR (dihydrofolate reductase), EHF (ets homologous factor), IVL (involucrin) KRT4 (keratin 4), MELANA (melan-A), NGAL (lipocalin 2), PDZK1IP1 (PDZK1 interacting protein interaction 1), P13 (peptidase inhibitor 3), PSME2 (proteasome activator subunit 2), and SERPINB3 (serpin peptidase inhibitor member 3).
“Sensitizing potential” means the risk for the test compound to provoke an immunological reaction when contacted with a mammal, preferably a human. Thus, sensitizing potential can be considered as the risk of developing a contact allergy to the test compound.
“Irritant potential” means the risk for the test compound to provoke a reversible inflammation of living tissue by chemical action at the contact site.
Preferably, the method according to the present invention allows evaluating whether the test compound is likely to induce a contact allergy or atopic dermatitis.
The present invention is particularly suited to identifying a large number of compounds. This simple and effective screening can be done in a very brief period of time. In particular, the methods described may be partially automated, thus allowing effective and simultaneous screening of diverse and numerous compounds, either in mixed or separate form.
Preferably, in the method according to the present invention, the expression level of each of said genes is determined by measuring the expression level of the polypeptides encoded by said gene or a fragment thereof, or by determining the expression level of the mRNA from said gene or a fragment thereof.
In one particularly preferred embodiment, the expression level of each of said at least six genes is determined by analysis of the expression of mRNA transcripts or mRNA precursors, such as a native RNA, of said gene. Said analysis can be done by preparing mRNA/cDNA from cells of a patient's biological sample, and hybridizing the mRNA/cDNA with a reference polynucleotide. The prepared mRNA/cDNA may be used in analysis by hybridization or amplification that includes, without being limiting, Southern and Northern analysis, PCR (“polymerase chain reaction”), such as quantitative PCR (Taqman) and the use of probes (“probe arrays”) such as GeneChip® DNA Matrices® (AFFYMETRIX).
Advantageously, the analysis of the mRNA expression transcript of each of said at least six genes involves a nucleic acid amplification process, such as, for example, RT-PCR (experimental method described in U.S. Pat. No. 4,683,202), ligase chain reaction (BARANY, Proc. Natl. Acad. Sci. USA, vol. 88, p: 189-193, 1991), self sustained sequence replication (GUATELLI et al., Proc. Natl. Acad. Sci. USA, vol. 87, p: 1874-1878, 1990) and transcriptional amplification system. (KWOH et al., Proc. Natl. Acad. Sci. USA, vol. 86, p: 1173-1177, 1989), “Q-Beta Replicase” (LIZARDI et al., Biol. Technology, vol. 6, p: 1197, 1988), “rolling circle replication” (U.S. Pat. No. 5,854,033) or any other nucleic acid amplification method, followed by a step of detecting the amplified molecules by techniques well known to the skilled person. These detection modes are particularly useful for detecting nucleic acid molecules in very small quantities. Thus, according to a preferred embodiment, the method according to the present invention comprises an additional step of amplifying the mRNA or cDNA of each of said six genes, the complementary sequence thereof or a fragment thereof.
Such as used here, amplification primers are defined as being a pair of nucleic acid molecules that can respectively pair with the 3′ and 5′ regions of a gene in a specific manner (positive and negative strands or vice versa) and encompassing a short region of said gene. Generally, amplification primers have a length of 10 to 30 nucleotides and allow amplifying a region of a length comprised between 50 and 200 nucleotides. Advantageously the primers used in the present invention are those listed in Table 1.
In another particularly preferred embodiment, the expression level of each of said at least six genes is determined by determining the expression level of the polypeptide encoded by said gene or a fragment thereof. Said analysis can be done by using an antibody (for example, a radiolabeled antibody, an antibody labeled with a chromophore, a fluorophore or an enzyme) an antibody derivative (for example, an antibody conjugated to a substrate or to a protein, or a ligand of a protein of a ligand/protein pair (for example biotin-streptavidin)) or an antibody fragment (for example, a single chain antibody, a hypervariable domain of an isolated antibody, etc.) which specifically binds the polypeptide encoded by said gene.
Said analyses can be done by many techniques known to the skilled person including, without being limiting, immunological tests based on the use of enzymatic activity (“enzyme immunoassay” EIA), immunological tests based on the use of radioactive isotopes (RIA), western blot analysis and ELISA (“enzyme linked immunosorbent assay”) tests.
In the sense of the present invention, “polypeptide” means a sequence comprising at least two amino acids, and the terms “polypeptide”, “peptide” and “protein” may be used interchangeably.
In the sense of the present invention, “mRNA or cDNA fragment” means a sequence of at least 50 nucleic acids, for example at least 100 or 150 nucleic acids, preferably at least 200 nucleic acids, for example at least 250 or 350 nucleic acids, and in a particularly preferred manner, a polypeptide [sic; nucleic acid sequence] of at least 400 nucleic acids.
In the sense of the present invention, “polypeptide fragment” means a sequence of at least 50 amino acids, for example at least 100 or 150 amino acids, preferably at least 200 amino acids, for example at least 250 or 350 amino acids, and in a particularly preferred manner, a polypeptide of at least 400 amino acids.
Preferably, the method according to the present invention also comprises a step of comparing the expression level of each of said at least six genes with a reference value. This reference value can serve as a positive and/or negative control.
A positive control can be conducted, for example, by comparing the expression level of said at least one gene in the presence of the test compound with the expression level of said at least one gene in the presence of a compound known to be sensitizing.
As an example of a compound known to be sensitizing, the following can be named: 2,4,6-trinitrobenzene sulfonic acid, p-phenylenediamine, dinitrochlorobenzene, benzaldehyde, resorcinol, tetramethylthiuram disulfide, oxazolone, chloroatranol, diphenylcyclopropenone, potassium dichromate, cinnamaldehyde, 2-bromo-2-(bromomethyl) glutaronitrile, glyoxal, saccharin, formaldehyde, trimellitic anhydride, methylchloroisothiazolinone, benzyl benzoate, alpha-hexyl cinnamaldehyde, eugenol, 2-mercaptobenzothiazole, isoeugenol, diphenylcyclopropenone (DCPP), lauryl gallate (LG), 3-3-dimethylaminopropylamine (3-DMAPA), cinnamaldehyde (CA), citral (Cal), 1,4-hydroquinone (HQ), glutaraldehyde (GA), 1,2-benzisothiazolin-3-one (Ben), phenylacetaldehyde (PA) and lilial (Li), preferably diphenylcyclopropenone, lauryl gallate, 1,4-hydroquinone and glutaraldehyde, and particularly preferably 1,4-hydroquinone.
Alternatively, in the present invention, a sensitizing compound can be used as a positive control, such as “fragrance mix”.
A negative control can be conducted in the absence of the test compound or in the presence of a compound known to be non-sensitizing, such as, for example, olive oil, glycerol, cetyltrimethylammonium bromide (CTAB) and dipropylene glycol.
In the scope of the present invention, we will conclude that a test compound has a sensitizing potential if an overexpression of said gene is observed with regard to its expression level in the absence of said test compound.
“Overexpression” means a significantly higher level of said gene compared to its normal expression level. Preferably, overexpression means an expression level in a biological sample that is greater by at least 20% than the normal expression level of said gene, preferably greater by at least 50% than the normal expression level of said gene, and more particularly preferably greater by at least 90% than the normal expression level of said gene.
“Expression level in the absence of said test compound” or “normal level” is the expression level of said gene in a control sample potentially corresponding to the biological sample of a patient who does not present sensitization or, preferably, to the mean of the expression level of said gene in different control samples.
Preferably, step b) of said method for evaluating sensitizing potential comprises measuring the expression of at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, at least 13, at least 14, at least 15, at least 16, at least 17, at least 18, at least 19, at least 20, at least 21, at least 22, at least 23, at least 24 and more preferentially, at least 25 genes chosen in the group made up of the genes such as defined in Table 1.
Thus, one can conclude that a test compound has a sensitizing potential if there is an overexpression of at least 6, at least 7, at least 8, at least 9, at least 10, at least 11, at least 12, at least 13, at least 14, at least 15, at least 16, at least 17, at least 18, at least 19, at least 20, at least 21, at least 22, at least 23, at least 24 and more preferentially, at least 25 genes chosen in the group made up of genes such as defined in Table 1.
In a particularly preferred manner, step b) of said method for evaluating sensitizing potential comprises determining the expression of the following group of genes: AKR1B10 (aldo-keto reductase family 1, member B10), AKR1C1 (aldo-keto reductase family 1, member C1), AKR1C2 (aldo-keto reductase family 1, member C2), CYP1B1 (cytochrome P450, family 1, subfamily B, polypeptide 1), FTH1P (ferritin, heavy polypeptide 1), FTL (ferritin, light polypeptide 1), G6PD (glucose-6-phosphate dehydrogenase), GCLM (glutamate-cysteine ligase modifier subunit), NQO2 (NAD(P)H dehydrogenase, quinone 2), SLC7A11 (solute carrier family 7, Member 11), TXNRD1 (thioredoxin reductase 1), UGT1A1 (UDP glucuronosyltransferase 1 family, polypeptide A1), UGT1A9 (UDP glucuronosyltransferase 1 family, polypeptide A9, YWHAZ (tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide), CD36 (CD36 molecule), CYP1A1 (cytochrome P450, family 1, subfamily A, polypeptide 1), GCLC (glutamate-cysteine ligase, catalytic subunit), HMOX1 (heme oxygenase 1), NQ01 (NAD(P)H dehydrogenase, quinone 1) PSME2 (proteasome activator subunit 2), and S100A8 (S100 calcium binding protein A8), preferably chosen in the group consisting of: AKR1B10 (aldo-keto reductase family 1, member B10), AKR1C1 (aldo-keto reductase family 1, member C1), AKR1C2 (aldo-keto reductase family 1, member C2), CYP1B1 (cytochrome P450, family 1, subfamily B, polypeptide 1), FTH1P (ferritin, heavy polypeptide 1), FTL (ferritin, light polypeptide 1), G6PD (glucose-6-phosphate dehydrogenase), GCLM (glutamate-cysteine ligase modifier subunit), NQO2 (NAD(P)H dehydrogenase, quinone 2), SLC7A11 (solute carrier family 7, Member 11), TXNRD1 (thioredoxin reductase 1), UGT1A1 (UDP glucuronosyltransferase 1 family, polypeptide A1), UGT1A9 (UDP glucuronosyltransferase 1 family, polypeptide A9, PSME2 (proteasome activator subunit 2), and YWHAZ (tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide).
In this particularly preferred embodiment, the test compound is determined to have sensitizing potential if at least 11 of said genes are overexpressed compared to a reference value.
In a particularly preferred manner, step b) of said method for evaluating sensitizing potential comprises determining the expression of at least one of the following group of genes: BRAK (CXC chemokine ligand 14), CTSS (cathepsin S), DAPK2 (death-associated protein kinase 2), FABP4 (fatty acid binding protein 4), HSP27 (heat shock 27 kDa protein), IL18 (IL-18), HSP90 (heat shock 90 kDa protein), IL1R2 (interleukin-1 receptor type II), TPSAB1 (tryptase alpha/beta 1), CXCR1 (interleukin 8 receptor, alpha), DEFB1 (defensin, beta 1), DHFR (dihydrofolate reductase), EHF (ets homologous factor), IVL (involucrin) KRT4 (keratin 4), MELANA (melan-A), NGAL (lipocalin 2), PDZK1IP1 (PDZK1 interacting protein interaction 1), PI3 (peptidase inhibitor 3) and SERPINB3 (serpin peptidase inhibitor member 3),
and even more preferentially, the group of genes BRAK (CXC chemokine ligand 14), CTSS (cathepsin S), DAPK2 (death-associated protein kinase 2), FABP4 (fatty acid binding protein 4), HSP27 (heat shock 27 kDa protein), IL18 (IL-18), IL1R2 (interleukin-1 receptor type II), HSP90 (heat shock 90 kDa protein), and TPSAB1 (tryptase alpha/beta 1), or the group of genes CXCR1 (interleukin 8 receptor, alpha), DEFB1 (defensin, beta 1), DHFR (dihydrofolate reductase), EHF (ets homologous factor), IVL (involucrin) KRT4 (keratin 4), MELANA (melan-A), NGAL (lipocalin 2), PDZK1IP1 (PDZK1 interacting protein interaction 1), PI3 (peptidase inhibitor 3) and SERPINB3 (serpin peptidase inhibitor member 3).
In this particularly preferred embodiment, the test compound is determined to have sensitizing potential if at least 7 of said genes, preferably at least 8 of said genes are overexpressed compared to a reference value.
In one particular embodiment, step b) of said method for evaluating the sensitizing potential of a test compound comprises a step a) of determining the expression level of at least 10, preferably at least 11, 12, 13, 14, 15, 16 and still more preferentially of the following group of genes: AKR1B10 (aldo-keto reductase family 1, member B10), AKR1C1 (aldo-keto reductase family 1, member C1), AKR1C2 (aldo-keto reductase family 1, member C2), CTGF (connective tissue growth factor), CYP1B1 (cytochrome P450, family 1, subfamily B, polypeptide 1), FTH1P (ferritin, heavy polypeptide 1), FTL (ferritin, light polypeptide 1), G6PD (glucose-6-phosphate dehydrogenase), GCLM (glutamate-cysteine ligase modifier subunit), IER3 (immediate early response 3), NQO2 (NAD(P)H dehydrogenase, quinone 2), SLC7A11 (solute carrier family 7, Member 11), TXNRD1 (thioredoxin reductase 1), UGT1A1 (UDP glucuronosyltransferase 1 family, polypeptide A1), UGT1A9 (UDP glucuronosyltransferase 1 family, polypeptide A9), YWHAZ (tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide), CD36 (CD36 molecule), CYP1A1 (cytochrome P450, family 1, subfamily A, polypeptide 1), GCLC (glutamate-cysteine ligase, catalytic subunit), HMOX1 (heme oxygenase 1), NQ01 (NAD(P)H dehydrogenase, quinone 1) and S100A8 (S100 calcium binding protein A8).
and optionally a step β) of measuring the expression level of at least 10, preferably 11, 12, 13, 14, 15, 16, 17, 18, 19 and more preferentially of the following group of genes: BRAK (CXC chemokine ligand 14), CTSS (cathepsin S), DAPK2 (death-associated protein kinase 2), FABP4 (fatty acid binding protein 4), HSP27 (heat shock 27 kDa protein), IL18 (IL-18), IL1R2 (interleukin-1 receptor type II), TPSAB1 (tryptase alpha/beta 1), HSP90 (heat shock 90 kDa protein), CXCR1 (interleukin 8 receptor, alpha), DEFB1 (defensin, beta 1), DHFR (dihydrofolate reductase), EHF (ets homologous factor), IVL (involucrin) KRT4 (keratin 4), MELANA (melan-A), NGAL (lipocalin 2), PDZK1IP1 (PDZK1 interacting protein interaction 1), P13 (peptidase inhibitor 3), PSME2 (proteasome activator subunit 2) and SERPINB3 (serpin peptidase inhibitor member 3), and
a step c) of determining the sensitizing potential of a test compound wherein the compound is determined to be sensitizing if:
Preferably, step b) is done between 2 and 24 hours after step a), still more preferably between 4 and 18 hours after step a), preferentially between 5 and 7 hours after step a) and most preferably of all, 6 hours after step a).
Another aspect of the invention relates to a method for evaluating the sensitizing power of a test compound, comprising the following steps:
1) obtaining at least one test compound dilution, and
2) determining the sensitizing potential of said test compound at said at least one dilution by a method such as defined according to any one of the preceding claims.
“Sensitizing power” means the ability of a given compound to induce a sensitization reaction according to the concentration of said compound. Sensitizing power is dependent on the quantity of substance necessary to induce sensitization. Thus, the lower the sensitizing quantity necessary to induce a sensitizing response, the stronger the sensitizer is, and vice versa, the higher the sensitizing quantity necessary to induce a sensitizing response, the weaker the sensitizer is.
It is thus possible to perform a quantitative analysis of the sensitizing potential of a compound.
Preferably, said test compound is subject to successive dilutions. Thus, steps 1) and 2) will be done for each of the dilutions.
Preferably, said successive dilutions will allow determining the maximum dilution at which said test compound retains sensitizing potential.
Said method for evaluating the sensitizing power of a test compound can also comprise a step of evaluating the sensitizing power of the test compound.
Thus, the more a product retains a sensitizing potential after successive dilutions, the more powerful a sensitizer the test compound is.
Moreover, the sensitizing power of a test compound will also be a function of the irritant potential of said test compound. Thus, the fact that a test compound has an irritant potential increases the sensitizing power of said test compound.
Consequently, in one preferred embodiment, said method also comprises a step of determining the irritant potential of the test compound.
The irritant potential of a test compound can be evaluated by using, for example, the method described in French patent 1051638.
Thus, one can conclude that a product is extremely sensitizing (Extreme E), if:
Thus, one can conclude that a product is strongly sensitizing (Strong S), if:
Thus, one can conclude that a product is moderately sensitizing (Moderate M), if:
Thus, one can conclude that a product is weakly sensitizing (weak W) if it does not have a sensitizing potential at dilutions below 1/2.
According to another aspect, the present invention relates to the use of at least one, preferably at least 2, at least 3, at least 4, at least 5, at least 6, at least 7 or at least 8 genes chosen in the group consisting of: BRAK (CXC chemokine ligand 14), CTSS (cathepsin S), DAPK2 (death-associated protein kinase 2), FABP4 (fatty acid binding protein 4), HSP27 (heat shock 27 kDa protein), IL18 (IL-18), HSP90 (heat shock 90 kDa protein), IL1R2 (interleukin-1 receptor type II), TPSAB1 (tryptase alpha/beta 1), CXCR1 (interleukin 8 receptor, alpha), DEFB1 (defensin, beta 1), DHFR (dihydrofolate reductase), EHF (ets homologous factor), IVL (involucrin) KRT4 (keratin 4), MELANA (melan-A), NGAL (gelatinase associated lipocalin), PDZK1IP1 (PDZK1 interacting protein interaction 1), PI3 (peptidase inhibitor 3), PSME2 (proteasome activator subunit 2), SERPINB3 (serpin peptidase inhibitor member 3), AKR1B10 (aldo-keto reductase family 1, member B10), AKR1C1 (aldo-keto reductase family 1, member C1), AKR1C2 (aldo-keto reductase family 1, member C2), CYP1B1 (cytochrome P450, family 1, subfamily B, polypeptide 1), FTH1P (ferritin, heavy polypeptide 1), FTL (ferritin, light polypeptide 1), G6PD (glucose-6-phosphate dehydrogenase), GCLM (glutamate-cysteine ligase modifier subunit), NQO2 (NAD(P)H dehydrogenase, quinone 2), SLC7A11 (solute carrier family 7, Member 11), TXNRD1 (thioredoxin reductase 1), UGT1A1 (UDP glucuronosyltransferase 1 family, polypeptide A1), UGT1A9 (UDP glucuronosyltransferase 1 family, polypeptide A9), and YWHAZ (tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide) for the in vitro evaluation of the sensitizing potential of a test compound.
The present invention also relates to a kit for the implementation of a method for in vitro evaluation of the sensitizing potential of a test compound, comprising means for determining the expression level of at least six genes selected from the group consisting of BRAK (CXC chemokine ligand 14), CTSS (cathepsin S), DAPK2 (death-associated protein kinase 2), FABP4 (fatty acid binding protein 4), HSP27 (heat shock 27 kDa protein), IL18 (IL-18), HSP90 (heat shock 90 kDa protein), IL1R2 (interleukin-1 receptor type II), TPSAB1 (tryptase alpha/beta 1), CXCR1 (interleukin 8 receptor, alpha), DEFB1 (defensin, beta 1), DHFR (dihydrofolate reductase), EHF (ets homologous factor), IVL (involucrin) KRT4 (keratin 4), MELANA (melan-A), NGAL (lipocalin 2), PDZK1IP1 (PDZK1 interacting protein interaction 1), PI3 (peptidase inhibitor 3), PSME2 (proteasome activator subunit 2), SERPINB3 (serpin peptidase inhibitor member 3), AKR1B10 (aldo-keto reductase family 1, member B10), AKR1C1 (aldo-keto reductase family 1, member C1), AKR1C2 (aldo-keto reductase family 1, member C2), CYP1B1 (cytochrome P450, family 1, subfamily B, polypeptide 1), FTH1P (ferritin, heavy polypeptide 1), FTL (ferritin, light polypeptide 1), G6PD (glucose-6-phosphate dehydrogenase), GCLM (glutamate-cysteine ligase modifier subunit), NQO2 (NAD(P)H dehydrogenase, quinone 2), SLC7A11 (solute carrier family 7, Member 11), TXNRD1 (thioredoxin reductase 1), UGT1A1 (UDP glucuronosyltransferase 1 family, polypeptide A1), UGT1A9 (UDP glucuronosyltransferase 1 family, polypeptide A9), YWHAZ (tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide), CD36 (CD36 molecule), CYP1A1 (cytochrome P450, family 1, subfamily A, polypeptide 1), GCLC (glutamate-cysteine ligase, catalytic subunit), HMOX1 (heme oxygenase 1), NQ01 (NAD(P)H dehydrogenase, quinone 1) and S100A8 (S100 calcium binding protein A8).
Preferably, said kit will comprise at least six primer pairs each amplifying at least one gene chosen from the group consisting of: BRAK (CXC chemokine ligand 14), CTSS (cathepsin S), DAPK2 (death-associated protein kinase 2), FABP4 (fatty acid binding protein 4), HSP27 (heat shock 27 kDa protein), IL18 (IL-18), IL1R2 (interleukin-1 receptor type II), HSP90 (heat shock 90 kDa protein), TPSAB1 (tryptase alpha/beta 1), CXCR1 (interleukin 8 receptor, alpha), DEFB1 (defensin, beta 1), DHFR (dihydrofolate reductase), EHF (ets homologous factor), IVL (involucrin) KRT4 (keratin 4), MELANA (melan-A), NGAL (gelatinase associated lipocalin), PDZK1IP1 (PDZK1 interacting protein interaction 1), P13 (peptidase inhibitor 3), PSME2 (proteasome activator subunit 2), SERPINB3 (serpin peptidase inhibitor member 3), AKR1B10 (aldo-keto reductase family 1, member B10), AKR1C1 (aldo-keto reductase family 1, member C1), AKR1C2 (aldo-keto reductase family 1, member C2), CYP1B1 (cytochrome P450, family 1, subfamily B, polypeptide 1), FTH1P (ferritin, heavy polypeptide 1), FTL (ferritin, light polypeptide 1), G6PD (glucose-6-phosphate dehydrogenase), GCLM (glutamate-cysteine ligase modifier subunit), NQO2 (NAD(P)H dehydrogenase, quinone 2), SLC7A11 (solute carrier family 7, Member 11), TXNRD1 (thioredoxin reductase 1), UGT1A1 (UDP glucuronosyltransferase 1 family, polypeptide A1), UGT1A9 (UDP glucuronosyltransferase 1 family, polypeptide A9), YWHAZ (tyrosine 3-monooxygenase/tryptophan 5-monooxygenase activation protein, zeta polypeptide), CD36 (CD36 molecule), CYP1A1 (cytochrome P450, family 1, subfamily A, polypeptide 1), GCLC (glutamate-cysteine ligase, catalytic subunit), HMOX1 (heme oxygenase 1), NQ01 (NAD(P)H dehydrogenase, quinone 1) and S100A8 (S100 calcium binding protein A8).
In a particularly preferred manner, said at least one primer pair is chosen in Table 1.
Skin pieces of 1.07 cm2 were purchased from EP1SKIN. Various substances were applied either in the liquid form (30 μL at different concentrations) or in the solid form (30 μL PBS or olive oil+30 μg or fewer to assess different powder concentrations) on the skin pieces. After an incubation of 15 min at room temperature, the skin pieces were washed with PBS (25 mL) and incubated 3 h, 6 h or 18 h at 37° C. in a CO2 incubator. After incubation, the skin pieces were sampled with a punch and separated from the collagen support. They were then directly placed in a “Tri Reagent” solution (Ambion) (1 ml) and immediately dissociated mechanically.
cDNA Preparation
The tissues were placed in a “Tri Reagent” solution (Ambion) and mechanically crushed. The RNA was prepared according to the protocol described by the supplier with isopropanol precipitation. To prepare the cDNA, the total RNAs were pretreated with DNAse to remove genomic DNA contaminants. One to 5 μg of total RNA was used for the treatment, with RNAse-free DNAse, RNAsin (1 μL) and random primers (3 μg). The superscript III RT (1.5 mL at 200 U/μL) was then added. The cDNAs were then tested by RT-PCR.
Quantitative PCR
Real time quantitative PCR was performed using the SYBR Green technology of Roche LC480 cyclers. The primers were designed to cover the intron-exon junctions to prevent any traces of genomic DNA amplification. Amplification gives amplicons between 100 and 150 bp. All the primer pairs were qualified by digestion with restriction enzymes and analyzed by electrophoresis. PCR was performed on 10 μL by using the Sybr green 2×PCR mix from Roche in PCR plates from Roche. Target gene expression was measured after RNA normalization by means of four housekeeping genes, and the values are expressed by using the CT method, and expressed in additional expression rates with regard to a theoretical zero (User Bulletin no. 2, Applied Biosystems, December 1997).
Results
For this analysis, an application of 15 min followed by washing and a post-incubation of 6 h were done before biopsy and analysis of the gene transcription. The results are shown in Table 1.
Moreover, 35 substances classified according to their characteristics (non-irritant (non-IRR), non-sensitizer (NS), irritant (IRR) or sensitizing by using the official classification of Extreme (E), Strong (S), Moderate (M) and Weak (W) were tested at different doses (Table 2). For analysis, the dose permitting the maximum response without inducing too much tissue destruction (corrosion) was selected.
Three groups of biomarkers were tested on the samples, those specific for irritation, those represented by the ARE gene family (genes under the control of ARE “antioxidant responsive element promoters”, i.e., AKR1B10, AKR1C1, AKR1C2, CYP1B1, FTH1P, FTL, G6PD, GCLM, NQO2, SLC7A11, TXNRD1, UGT1A1, UGT1A9, YWHAZ, CD36, CYP1A1, GCLC, HMOX1, NQO1, PSME2 and S100A8 genes) and another group of genes specific for sensitization, notably for sensitizing substances that do not induce ARE genes.
Irritants for which the expression of the IL-8 gene is 50 times greater than the control and that induce a non-specific expression of ARE genes were retested at lower doses.
The results are presented in Tables 2 and 3, with a code according to the degree of overexpression of the genes. If the expression is greater than 1.3 compared to the control, a grade of 11s given; if this expression is lower, the grade is 0. Note that, preferably, if the number of ARE genes is greater than 11, one can conclude that the substance is certainly sensitizing. For substances that do not strongly induce ARE genes, the other group of sensitization genes is analyzed.
Observe that, preferably, if at least 8 of these genes are overexpressed, then the substance is clearly sensitizing.
Preferably, said test is done both on the group of ARE genes and the group of “non-ARE” genes.
In order to be able to evaluate the sensitizing power of the compounds, a selection of compounds was subjected to successive dilutions in order to be tested again for their sensitizing potential, as shown in Table 3.
| Number | Date | Country | Kind |
|---|---|---|---|
| 1051636 | Mar 2010 | FR | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/FR11/00122 | 3/7/2011 | WO | 00 | 9/5/2012 |
