Patent Application
20230192769
The instant application contains a Sequence Listing which has been submitted via EFS-Web and is hereby incorporated by reference in its entirety. Said ASCII copy, created on Feb. 19, 2021, is named 46761US_sequencelisting.txt, and is 4,889 bytes in size.
The invention relates to the field of biomedicine, and in particular to a polypeptide against various enterovirus and applications thereof.
Enterovirus is a positive-sense single-stranded RNA virus, and belongs to the Enterovirus genus of the Picornaviridae family, mainly including human Enterovirus (EV), Coxsackie A virus (CVA), Coxsackie B virus (CVB), Echovirus, Rhinovirus, and Poliovirus. Enterovirus infections are widely distributed around the world and exhibit complex and diverse clinical manifestations, ranging from mild fever, fatigue, respiratory diseases, to herpes angina, hand-foot-and-mouth disease, and to severe aseptic meningitis, myocarditis, encephalitis, poliomyelitis, etc. At present, there is a lack of specific drugs that can effectively treat or prevent enterovirus infections.
Herpetic angina is mainly caused by Coxsackievirus Group A type 2 (CVA2), CVA4, CVA6, CVA9, CVA16, CVA22, and Coxsackievirus group B type 1 (CVB1), CVB2, CVB3, CVB4, or CVB5. Herpetic angina often causes fever, and the temperature is mostly not high or moderate. Occasionally, the fever is as high as 40° C. or even causing convulsions. The fever may last about 2 to 4 days. Older children may complain of sore throat, which can affect swallowing. Infants and young children may show salivation, refusal to eat, and restlessness. Sometimes it is accompanied by headache, abdominal pain or myalgia. About 25% of children under 5 years old with herpetic angina may be accompanied by vomiting. The patient may show typical symptoms in the pharynx, including pharyngeal hyperemia, and several (from 1 to 2 up to more than 10) small (1-2 mm in diameter) gray-white herpes surrounded by redness in the oral mucosa within 2 days of onset. After 2 to 3 days, the redness increases and the herpes rupture to form a yellow ulcer. This mucosal rash is more common in the anterior column of the tonsils, but also in the soft palate, uvula, and tonsils, but does not involve the gums and buccal mucosa. The course of the disease is usually 4 to 6 days, occasionally extended to 2 weeks.
Hand-foot-and-mouth disease is mainly caused by enterovirus 71 (EV71), CVA6, CVA8, CVA10, CVA16, CVB3 and CVB5. The common clinical manifestations of hand-foot-and-mouth disease include acute fever, mouth pain, anorexia, and scattered herpes or ulcers in the oral mucosa, mostly on the tongue, buccal mucosa, and hard palate, and also affecting soft palate, gums, tonsils and pharynx. Maculopapular rashes appear in the hands, feet, buttocks, arms and legs, and then turn into herpes which are surrounded by inflammatory redness and contains less fluid in the blister. Typically, there are more rashes on the hands and feet, both on the dorsum and the vola, from a few to dozens, and after subsided, they leaves no traces and no pigmentation. Some children with hand-foot-and-mouth disease have herpetic angina as the first symptom, and then red rashes in the palm, sole, buttocks and other parts. When the course of the disease develops rapidly, a small number of children can develop from hand-foot-and-mouth disease to severe aseptic meningitis and encephalitis, manifested as fever, headache, nausea, vomiting, and then meningeal irritation, as well as body temperature fluctuations with low-grade fever in the most case and sometimes with fever up to 40° C. or more, often bimodal fever in the course of the disease. Other symptoms include such as sore throat, muscle aches, skin rash, photophobia, diarrhea, swollen lymph nodes, and sometimes mild paralysis.
Myocarditis is mainly caused by CVB1-61 and Echovirus. Depend on the extent and location of the disease, the clinical manifestations of patients with viral myocarditis include asymptomatic case in mild case to heart failure, cardiogenic shock and sudden death in severe case. Patients often have a history of upper respiratory or intestinal infections 1 to 3 weeks before the onset of symptoms, manifested as fever, body aches, sore throat, fatigue, nausea, vomiting, diarrhea and other symptoms, and then palpitations, chest tightness, chest pain or precordial pain, dizziness, dyspnea, edema, and even Adams-Stokes syndrome, and in some patients, heart failure or cardiogenic shock.
Enterovirus is a positive-sense single-stranded RNA virus, which has a genome of about 7.5 kb, containing a large ORF encoding a polyprotein. The polyprotein can be further hydrolyzed into 4 structural proteins (VP1-VP4) and 7 nonstructural proteins (2A-2C and 3A-3D). In enteroviruses (including EV71, CVA and CVB), protein 3A is an extremely conserved nonstructural protein, which exists in the form of homodimers in the intracellular membrane and plays an important role in the replication of viruses and the regulation of host innate immunity.
After being infected by the virus, the host cell will activate a series of natural immune mechanisms, including RNA interference (RNAi)-mediated antiviral immunity. After the virus infects the host cell, due to the structure of the virus genome or replication intermediates, long double-stranded RNA (dsRNA) derived from the virus will be produced. These dsRNAs are recognized by the host Dicer protein and cleaved into viral small interfering RNA (vsiRNA). Then, vsiRNA binds with Argonaute (AGO) protein to form RNA-induced silencing complex (RISC), which ultimately mediates the degradation of the viral target gene RNA, thereby inhibiting the replication of the virus to eliminate the virus.
In view of this, the present invention provides a polypeptide and application thereof.
In order to achieve the above-mentioned purpose of the invention, the present invention provides the following technical solutions.
The present invention provides use of enterovirus RNA suppressing protein (ERSP) as a target in the preparation of a medicine for preventing and/or treating viral diseases.
The present invention also provides use of a polypeptide in the preparation of an inhibitor of ERSP, wherein the function of ERSP is inhibited by the polypeptide, and the viral nucleic acid is cut by Dicer (endoribonuclease Dicer) to produce viral small interfering RNA (vsiRNA).
The invention also provides use of a polypeptide in the preparation of a medicine for preventing and treating viral diseases.
In some specific embodiments of the present invention, the ERSP is enterovirus nonstructural protein 3A.
In some specific embodiments of the present invention, the enterovirus belongs to the Picornaviridae enterovirus genus, including human Enterovirus (EV), Coxsackie A virus (CVA), Coxsackie B virus (CVB), Echovirus, Rhinovirus, and Poliovirus.
In some specific embodiments of the present invention, the viral diseases include hand-foot-and-mouth disease, myocarditis, herpes angina, aseptic meningitis, encephalitis and viral cold.
In some specific embodiments of the present invention, the amino acid sequence of the polypeptide comprises CR, CK and/or DLL.
In some specific embodiments of the present invention, the polypeptide has a sequence selected from:
I. (X1) (X2)DLL, (X2)DLL(X3), DLL(X3) (X4), (X5)YC(X6), C(X6),
wherein,
X1 is isoleucine (I),
X2 is selected from serine (S) or alanine (A),
X3 is selected from alanine (A) or lysine (K) or glutamine (Q) or arginine (R) or serine (S) or cysteine (C),
X4 is selected from serine (S) or alanine (A),
X5 is selected from glutamic acid (E) or glutamine (Q),
X6 is selected from arginine (R) or lysine (K); or
II. a sequence with deletion, addition or substitution of at least one amino acid in the sequence in I; or
III. a sequence inhibiting the activity of ERSP and having at least 50% homology to the sequence in I or II; or
IV. the complementary sequence of the sequence in I or II or III.
The “amino acid” in the present invention includes natural amino acids or unnatural amino acids. Amino acid types well known to those skilled in the art are within the scope of the present invention.
In some specific embodiments of the present invention, the sequences of I is as shown in any one of SEQ ID NOs: 1-14, without the sequence of cell-penetrating peptide and the sequence of peptide linker.
The present invention also provides a polypeptide capable of inhibiting the activity of ERSP.
In some specific embodiments of the present invention, the amino acid sequence of the polypeptide comprises CR, CK and/or DLL.
In some specific embodiments of the present invention, the amino acid sequence of the polypeptide comprises YCR and/or YCK.
In some specific embodiments of the present invention, the polypeptide has a sequence selected from:
I. (X1) (X2)DLL, (X2)DLL(X3), DLL(X3) (X4), (X5)YC(X6), C(X6),
wherein,
X1 is isoleucine (I),
X2 is selected from serine (S) or alanine (A),
X3 is selected from alanine (A) or lysine (K) or glutamine (Q) or arginine (R) or serine (S) or cysteine (C),
X4 is selected from serine (S) or alanine (A),
X5 is selected from glutamic acid (E) or glutamine (Q),
X6 is selected from arginine (R) or lysine (K); or
II. a sequence with deletion, addition or substitution of at least one amino acid in the sequence in I; or
III. a sequence inhibiting the activity of ERSP and having at least 50% homology to the sequence in I or II; or
IV. the complementary sequence of the sequence described in I or II or III.
In some specific embodiments of the present invention, the sequence of the polypeptide in I is as shown in any one of SEQ ID NOs: 1-14, without the sequence of penetrating peptide and the sequence of peptide linker.
On this basis, the present invention also provides a nucleic acid having a nucleotide sequence encoding the polypeptide.
The present invention also provides a recombinant vector comprising the nucleic acid.
On this basis, the present invention also provides a host cell comprising the recombinant vector.
The present invention also provides a medicine comprising the polypeptide and pharmaceutically acceptable excipients.
The present invention also provides a vaccine comprising the polypeptide and pharmaceutically acceptable excipients.
The invention also provides a method for treating enterovirus infections comprising oral administration or injection of the medicine to a subject in need thereof, wherein the injection is intramuscular injection, intraperitoneal injection or intravenous injection.
The present invention also provides a method for preventing enterovirus infections comprising administration of the vaccine to a subject in need thereof.
In the present invention, the term “prevent”, “preventing” or “prevention” means that various methods or measures for preventing the occurrence or development of diseases, including medical, physical or chemical methods for preventing or reducing the occurrence or development of various symptoms of diseases are performed before the occurrence of diseases confirmed by clinical standards.
In the present invention, the term “treat”, “treating” or “treatment” means that various methods or measures are performed to prevent and reduce the occurrence or development of the disease, inhibit, suppress, reduce, improve, slow down, stop, delay or reverse the development or aggravation of the disease course, alleviate or reduce various indicators, including symptoms or complications of diseases, disorders or conditions, or cure or eliminate diseases, disorders or conditions.
In the present invention, the term “medicine” refers to a single compound, a composition of multiple compounds, or a composition or formulation with a single compound as the main active ingredient, or a composition or formulation with multiple compounds as active ingredients, which can be used to prevent or treat a certain disease. A “medicine” should be understood as not only to refer to a product approved for production by the administrative agency in accordance with the laws and regulations of a country, but also to refer to various material forms formed with a single compound as the active ingredient in order to achieve the approval for production. “Formed” should be understood as obtaining through chemical synthesis, biological transformation or purchase.
The present invention also provides an inhibitor of enterovirus 71, wherein the inhibitor is polypeptide P2 with the amino acid sequence shown in SEQ ID NO: 2.
The present invention also provides variants of the inhibitor, wherein the variant is 3A-TAT-EP with the amino acid sequence as shown in SEQ ID NO: 3, 3A-EP-DRI with the amino acid sequence as shown in SEQ ID NO: 4, or 3A-EP-PEG4-PA with the amino acid sequence as shown in SEQ ID NO: 5.
In addition, the present invention also provides use of the inhibitor or the variants in the preparation of an inhibitor of enterovirus.
RNA interference is an antiviral immune mechanism. In the antiviral process with RNA interference, the double-stranded RNA produced during viral RNA replication is recognized by the host Dicer protein and cleaved into small interfering RNA (siRNA). These virus-derived small interfering RNAs (vsiRNAs) are transferred and assembled into RNA-induced silencing complexes, which mediate the degradation of homologous viral RNA to achieve antiviral goals. For example, the nonstructural protein 3A of EV71 can bind to the viral double-stranded RNA to prevent it from being cut by Dicer, and thus inhibit the production of virus-derived small interfering RNAs (vsiRNAs), so as to achieve the purpose of escaping from the host anti-viral mechanism via RNA interference.
The present invention provides a series of polypeptides with antiviral activity. The present invention provides a new strategy for preventing and controlling enterovirus such as EV71, CVA16, CVA6, CVB3, and CVB5 viruses and provides a new theoretical basis for accelerating the research and development of a polypeptide small molecule drug against enterovirus such as EV71, CVA16, CVA6, CVB3, and CVB5 viruses.
The present invention discloses polypeptides and uses thereof. Those skilled in the art can learn from the contents of the present invention and appropriately improve the process parameters. It is to be understood that all such alternatives and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The method and the application of the present invention have been described according to the preferred embodiments, and it is obvious that the method and application described herein may be changed or appropriately modified and combined without departing from the content, spirit and scope of the present invention.
The EV71 3A protein contains 86 amino acid residues. Protein 3A has the ability to form dimer, and its dimerization plays a key role in the proper functioning of 3A. Based on the composition and sequence characteristics of the two helical structures of the dimerization domain of protein 3A, the applicant designed polypeptide EP (shown in SEQ ID NO: 1), which can bind to the EV71 nonstructural protein 3A and interfere with the dimer formation of protein 3A, thereby inhibiting virus replication and infection.
In order to allow the inhibitor to penetrate the cell membrane and enter the cell to inhibit viruses, polypeptide P2 (SEQ ID NO: 2) is designed using polypeptide EP as the core sequence. P2 polypeptide is capable of competing with al, thereby preventing dimerization of 3A, inhibiting the function of 3A in anti-innate immunity, and finally achieving anti-viral purposes.
Based on P2, a series of variants are constructed according to the modification of P2. It is shown by experiments that the variants of P2 have improved ability to inhibit viruses, which gives great significance to the prevention and treatment of diseases caused by enteroviruses.
The variants include 3A-TAT-EP with the amino acid sequence as shown in SEQ ID NO: 3, 3A-EP-DRI with the amino acid sequence as shown in SEQ ID NO: 4, and 3A-EP-PEG4-PA with the amino acid sequence as shown in SEQ ID NO: 5.
The present invention also provides uses of the inhibitor of enterovirus 71, comprising preparing the inhibitor of enterovirus 71 using polypeptide P2 or the variants of polypeptide P2, or preparing the inhibitor of enterovirus 71 using polypeptide P2 or the variants of polypeptide P2 together with other effective ingredients.
The present invention also includes an inhibitor with the activity of inhibiting EV71, which is obtained by using different cell-penetrating sequence, by modifying the sequence of or by using unnatural amino acids in polypeptide P2.
Enterovirus 3A protein is a high-efficiency ERSP which can bind to viral dsRNA to prevent it from being cut by Dicer, and thus inhibit the production of virus-derived vsiRNA, thereby avoiding the antiviral immunity of the host by RNAi pathway.
The polypeptide and the derivatives thereof according to the present invention are capable of inhibiting the function of enterovirus protein 3A, and may be an emerging therapeutic drug for EV71, which targets new targets and is of great significance for avoiding antiviral drug resistance.
Compared with the prior art, the present invention has the following advantages:
The P2 polypeptide and variants thereof have potent antiviral activity. This will provide a new strategy for the prevention and treatment of enterovirus, also provide a new theoretical basis for accelerating the development of anti-enterovirus polypeptide small molecule drugs. In addition, the clear antiviral mechanism of the P2 series polypeptides can ensure the safety for their application and the clarity for the optimization approach, which is convenient for further development in the future.
The polypeptides provided by the present invention are shown in Table 1.
In the present invention, polypeptides RRRRRRRR (R8) and YGRKKRRQRRR (TAT) are penetrating peptides, GSG is a peptide linker, and the amino acid sequences without the penetrating peptide and the peptide linker are the core sequences. In each example of the present invention, a negative control polypeptide is provided to show that the core sequences of the polypeptides in the present invention have good antiviral effects.
The materials and reagents used in the present invention are commercially available.
The present invention will be further explained below in conjunction with examples.
MEM medium (Thermo), serum (Gibco), immunofluorescence plate (NEST), PBS, DAPI, and paraformaldehyde were purchased in the market.
Polypeptide P2 was synthesized by Nanjing GenScript Company, and its sequence is shown in SEQ ID NO: 2.
The experiment was performed in two groups in order to observe whether the addition of EV71 virus affect the entry of polypeptides into cells. In one group, EV71 virus and then polypeptide P2 were added, and in the other group, only the polypeptide was added. Negative control was set in each group.
Immunofluorescence experiment was performed as follows.
(1) 1 ml of RD cells in a special dish for immunofluorescence were treated and then collected at 30% confluence.
(2) The medium in the dish was aspirated, and the dish was washed three times (5 minutes for each wash) with 1 ml of 0.01 mol/L PBS (pH 7.4) to remove residual medium.
(3) 4% paraformaldehyde solution was prepared by dissolving 4 g paraformaldehyde solid in 100 ml PBS. Then 1 ml of the prepared 4% paraformaldehyde solution was added to each dish and incubated for 5 minutes to fix the cells.
(4) The 4% paraformaldehyde solution was aspirated, and the dish was washed three times (5 minutes for each wash) with 1 ml of 0.01 mol/L PBS (pH 7.4) to remove residual paraformaldehyde.
(5) 1 mg/ml DAPI solution was diluted with PBS to 100 ng/ml, and the diluted DAPI solution was added to the dish and incubated for 15 minutes.
(6) The solution was aspirated, and the dish was washed three times (5 minutes for each wash) with 1 ml of 0.01 mol/L PBS (pH 7.4) to remove residual solution.
(7) The dish was observed under a fluorescence microscope.
Polypeptides were labeled with fluorescence and tested for their membrane penetration efficiency in RD cells. Two groups of experiments were performed. One group was control group without virus infection, in which R8 and P2 were added respectively; the other group was EV71 infection group, in which cells were infected with EV71 and then R8 and P2 were added respectively. The two groups of experiment were carried out at the same time, with virus M01=0.1, and a polypeptide concentration of 1 μM. The cells were fixed 12 h after the addition of the polypeptide, immunofluorescence experiments were performed, and the nuclei were stained with DAPI. The results show that the polypeptides can enter cells infected with or without virus, showing a good ability to penetrate cell membranes.
As shown in
CCK-8 reagent was from MCE.
Polypeptide P2 was desired to be able to inhibit viruses, and also to be non-toxic to cells. Therefore, the cytotoxicity test was used for detection, and untreated cells were used as the control group.
The experiment was performed as follows.
(1) RD cells were plated in a 96-well plate at 100 μl per well.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum. Then, polypeptide P2 was added to generate gradient concentrations of 0.01 μM, 0.1 μM, 1 μM, 10 μM, and 100 μM (final concentration), respectively.
(3) The test was performed 24 hours after the addition of the polypeptide, and 10 μl of viable cell detection reagent CCK-8 was added to each well and mixed well.
(4) The plate was incubated at 37° C. for 2 h.
(5) The absorbance value at OD450 was measured with a microplate reader.
The results are shown in
Total RNA extraction kit (Omega), 24-well plate, 100 mm dish, and 50 ml syringe, 0.22 μm filter membrane (Millipore), one step qRT-PCR kit (Takara) were purchased in the market. The water used in the RNA extraction and qRT-PCR was DEPC-treated water, and the entire experiment was carried out in an RNase free environment.
(1) RD cells were plated in five 100 mm dishes.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum. Then, 1 μl EV71 virus, CVA16 virus, CVB3 virus, or CVB5 virus at 10{circumflex over ( )}7 PFU/ml were added, respectively.
(3) After 2 days, the cells were observed to see if the cytopathic effect (CPE) phenomenon occurred. When the changes were obvious, samples were collected as follows.
(4) The supernatant in the 100 mm dish was transferred into a 15 ml centrifuge tube, and centrifuged at 500 g for 5 min.
(5) The supernatant was transferred into a new 15 ml centrifuge tube, and filtered through 0.22 μm filter membrane with a 50 ml syringe.
(6) RNA was extracted from 100 μl of the supernatant obtained in step (5) and subjected to one step qRT-PCR to measure the virus titer, and the previously extracted virus RNA with known titer was handled together as a control.
(1) Different cells were plated in 24-well cell plates.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum (0.5 ml/well), and 5 μl of 10{circumflex over ( )}6 PFU/mL EV71 viruses per well were added.
(3) After 1 h, different polypeptides were added at a final concentration of 0.01 μM, 0.1 μM, 1 μM, 10 μM, and 50 μM, respectively.
(4) Samples were collected 24 hours after virus infection, and RNA was extracted with total RNA extraction kit as follows.
(5) The supernatant in the wells was discarded, then 350 μl of TRK Lysis Buffer was added to each well and the plate was shaken on the shaker for 5 minutes.
(6) 350 μl of 70% ethanol (DEPC-treated) was added to the well and the plate was shaken on the shaker for 5 minutes.
(7) The mixture in the well was transferred to a RNA extraction column and centrifuged at 12,000 g for 1 min.
(8) The solution collected in the recovery tube was added back to the column and centrifuged at 12,000 g for 1 min.
(9) RNA washing buffer 1 was added to the column and centrifuged at 12,000 g for 30s.
(10) RNA washing buffer 2 was added to the column and centrifuged at 12,000 g for 1 min.
(11) Step (10) was repeated once.
(12) The column was centrifuged at 12000 g for 2 min to completely remove residual RNA washing buffer.
(13) 50 μl DEPC-treated H2O was added to the column and centrifuge at 12,000 g for 2 min.
(14) 2 μl RNA sample was used according to one step qRT-PCR kit for fluorescence quantification experiment.
RD cells added with R8 penetrating peptide (sequence: RRRRRRRR) were used as a negative control.
The results are shown in
RD cells were used to test the antiviral effect of polypeptide P2. EV71 (MOI=0.1) was added to RD cells at 80% confluence. After 1 hour of infection, polypeptide P2 was added at concentrations of 0.01 μM, 0.1 μM, 1 μM, 10 μM, and 50 μM, respectively. The samples were collected 24 hours later, and the total RNA was extracted. The level of viral genomic RNA was detected by qRT-PCR. The cells infected with the same type virus and added with penetrating peptide R8 were used as a control group. The results showed that with the increase of the polypeptide concentration, the viral RNA level decreased significantly, demonstrating that polypeptide P2 has obvious anti-EV71 activity.
HEK293T, Vero, and Huh7.5 cells
(1) 293T cells, Vero cells and Huh7.5 cells were plated in 24-well plates respectively.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum (0.5 ml/well), and 5 μl of 10{circumflex over ( )}6 PFU/mL EV71 virus per well was added.
(3) After 1 h, polypeptide P2 was added to different cells at a final concentration of 0.01 μM, 0.1 μM, 1 μM, 10 μM, and 50 μM, respectively.
(4) Samples were collected 24 hours after virus infection, and RNA was extracted with a total RNA extraction kit as follows.
(5) The supernatant in each well was discarded, then 350 μl of TRK Lysis Buffer was added to the well and the plate was shaken on the shaker for 5 minutes.
(6) 350 μl of 70% ethanol (DEPC-treated) was added to the well and the plate was shaken on the shaker for 5 minutes.
(7) The mixture in the well was transferred to a RNA extraction column and centrifuged at 12,000 g for 1 min.
(8) The solution collected in the recovery tube was added back to the column and centrifuged at 12,000 g for 1 min.
(9) RNA washing buffer 1 was added to the column and centrifuged at 12,000 g for 30s.
(10) RNA washing buffer 2 was added to the column and centrifuged at 12,000 g for 1 min.
(11) Step (10) was repeated once.
(12) The empty column was centrifuged at 12,000 g for 2 min to completely remove residual RNA washing buffer.
(13) 50 μl DEPC-treated H2O was added to the column and centrifuge at 12,000 g for 2 min.
(14) 2 μl RNA sample was used according to one step qRT-PCR kit for fluorescence quantification experiment.
It can be seen in
The IC50 values measured in 293T cells, Vero cells and Huh7.5 cells were 9.677 μM, 1.958 μM and 1.842 μM, respectively.
Polypeptides 3A-TAT-EP (shown in SEQ ID NO: 3), 3A-EP-DRI (shown in SEQ ID NO: 4) and 3A-EP-PEG4-PA (shown in SEQ ID NO: 5) were used and were all synthesized by company.
(1) 293T cells were plated in a 24-well cell plate.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum (0.5 ml/well), and 5 μl of 10{circumflex over ( )}6 PFU/mL EV71 virus per well was added.
(3) After 1 hour, polypeptides P2, 3A-TAT-EP, 3A-EP-DRI and 3A-EP-PEG-PA were added at a final concentration of 0.01 μM, 0.1 μM, 1 μM, and 10 μM, respectively.
(4) Samples were collected 24 hours after virus infection, and RNA was extracted with a total RNA extraction kit.
(5) The supernatant in each well was discarded, then 350 μl of TRK Lysis Buffer was added to the well and the plate was shaken on the shaker for 5 minutes.
(6) 350 μl of 70% ethanol (DEPC-treated) was added to the well and the plate was shaken on the shaker for 5 minutes.
(7) The mixture in the well was transferred to a RNA extraction column and centrifuged at 12000 g for 1 min.
(8) The solution collected in the recovery tube was added back to the column and centrifuged at 12,000 g for 1 min.
(9) RNA washing buffer 1 was added to the column and centrifuged at 12,000 g for 30s.
(10) RNA washing buffer 2 was added to the column and centrifuged at 12,000 g for 1 min.
(11) Step (10) was repeated once.
(12) The empty column was centrifuged at 12,000 g for 2 min to completely remove residual RNA washing buffer.
(13) 50 μl DEPC-treated water was added to the column and centrifuge at 12000 g for 2 min.
(14) 2 μl RNA sample was used according to one step qRT-PCR kit for fluorescence quantification experiment.
(1) RD cells in good growth state were plated in a 96-well plate at 1×104 cells per well and cultured in 5% CO2 at 37° C. for 24 h.
(2) polypeptides (3A-TAT-EP, 3A-EP-DRI) were diluted in 2-fold series with MEM containing 2% FBS to obtain 40 μM, 20 μM, 10 μM, 5 μM, 2.5 μM, 1.25 μM, 0.625 μM, 0.313 μM concentrations at a final volume of 100 μl in a new 96-well plate. Each concentration was tested in triplicate.
(3) The diluted virus solution was added to the plate of step (1), 100 μL per well with the final virus concentration was 0.1 MOI. Wells without polypeptide and virus (well without treatment), wells with virus only were used as controls.
(4) The mixture of step (2) was added to the 96-well plate plated with cells in step (1) and incubated in 5% CO2 at 37° C. for 24 h. Then CCK8 kit was used to determine the inhibitory effect of the polypeptide on virus.
(5) The inhibition rate of different concentrations of polypeptides on viral infection was calculated using the following formula:
OD means the value of OD450-OD630, inhibition rate=(OD well with treatment−OD well with virus only)×100%/(OD well without treatment−OD well with virus only)
The results are shown in
In
MEM medium (Thermo), serum (Gibco), immunofluorescence plate (NEST), PBS, DAPI, and paraformaldehyde were purchased from markets.
Polypeptide P1 was synthesized by Nanjing GenScript Company, and its sequence is shown in SEQ ID NO: 6.
The experiment was performed in two groups in order to observe whether the addition of EV71 virus affects the entry of polypeptides into cells. In one group, EV71 virus and then polypeptide P2 were added, and in the other group, only the polypeptide was added. Negative control was set in each group.
Immunofluorescence experiment was performed as follows.
(1) 1 ml of RD cells in a special dish for immunofluorescence were treated and then collected at 30% confluence.
(2) The medium in the dish was aspirated, and the dish was washed three times (5 minutes for each wash) with 1 ml of 0.01 mol/L PBS (pH 7.4) to remove residual medium.
(3) 4% paraformaldehyde solution was prepared by dissolving 4 g paraformaldehyde solid in 100 ml PBS. Then 1 ml of the prepared 4% paraformaldehyde solution was added to each dish and incubated for 5 minutes to fix the cells.
(4) The 4% paraformaldehyde solution was aspirated, and the dish was washed three times (5 minutes for each wash) with 1 ml of 0.01 mol/L PBS (pH 7.4) to remove residual paraformaldehyde.
(5) 1 mg/ml DAPI solution was diluted with PBS to 100 ng/ml, and the diluted DAPI solution was added to the dish and incubated for 15 minutes.
(6) The solution was aspirated, and the dish was washed three times (5 minutes for each wash) with 1 ml of 0.01 mol/L PBS (pH 7.4) to remove residual solution.
(7) The dish was observed under a fluorescence microscope.
Polypeptides were labeled with fluorescence and tested for their membrane penetration efficiency in RD cells. Two groups of experiment were performed. One group was control group without virus infection, in which blank, R8, P1 and P2 were added respectively; the other group was EV71 infection group, in which cells were infected with EV71 and then blank, R8, P1 and P2 were added respectively. The two groups of experiment were carried out at the same time, with virus MOI=0.1, and a polypeptide concentration of 1 μM. The cells were fixed 12 h after the addition of the polypeptide, immunofluorescence experiments were performed, and the nuclei were stained with DAPI. The results show that the polypeptides can enter cells infected with or without virus, showing a good ability to penetrate cell membranes.
As shown in
CCK-8 reagent was from MCE.
Polypeptide P1 was desired to be able to inhibit viruses, also to be non-toxic to cells. Therefore, the cytotoxicity test was used for detection, and untreated cells were used as the control group.
The experiment was performed as follows.
(1) RD cells were plated in a 96-well plate at 100 μl per well.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum. Then, polypeptide P1 was added to generate gradient concentrations of 0.01 μM, 0.1 μM, 1 μM, 10 μM, and 100 μM (final concentrations), respectively.
(3) The test was performed 24 hours after the addition of the polypeptide, and 10 μl of viable cell detection reagent CCK-8 was added to each well and mixed well.
(4) The plate was incubated at 37° C. for 2 h.
(5) The absorbance value at OD450 was measured with a microplate reader.
The results are shown in
RD cells were used to test the antiviral effect of polypeptide P1. When RD cells reached 80% confluence, polypeptide P1 was added at concentrations of 0 μM (control group), 0.01 μM, 0.1 μM, 1 μM, 10 μM, and 100 μM, respectively. Three parallel wells were used for each concentration. The test was carried out 24 hours later, and the cell viability was detected using the CCK-8 kit. The results showed that there was no significant difference in the cell survival rate between the group added with 100 μM polypeptide P1 and the control group, indicating that polypeptide P1 is not toxic to cells within 100 μM.
CCK-8 reagent was from MCE.
Polypeptide 3A-TAT-EP was desired to be able to inhibit viruses, and also to be non-toxic to cells. Therefore, the cytotoxicity test was used for detection, and untreated cells were used as the control group.
The experiment was performed as follows.
(1) RD cells were plated in a 96-well plate at 100 μl per well.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum. Then, polypeptide 3A-TAT-EP was added to generate gradient concentrations of 0.01 μM, 0.1 μM, 1 μM, 10 μM, and 100 μM (final concentrations), respectively.
(3) The test was performed 24 hours after the addition of the polypeptide, and 10 μl of viable cell detection reagent CCK-8 was added to each well and mixed well.
(4) The plate was incubated at 37° C. for 2 h.
(5) The absorbance value at OD450 was measured with a microplate reader.
The results are shown in
RD cells were used to test the antiviral effect of polypeptide 3A-TAT-EP. When RD cells reached 80% confluence, polypeptide 3A-TAT-EP was added at concentrations of 0 μM (control group), 0.01 μM, 0.1 μM, 1 μM, 10 μM, and 100 μM, respectively. Three parallel wells were used for each concentration. The test was carried out 24 hours later, and the cell viability was detected using the CCK-8 kit. The results showed that there was no significant difference in the cell survival rate between the group added with 100 μM polypeptide 3A-TAT-EP and the control group, indicating that polypeptide P1 is not toxic to cells within 100 μM.
CCK-8 reagent was from MCE.
Polypeptides 3A-EP-DRI and 3A-EP-PEG4-PA were desired to be able to inhibit viruses, and also to be non-toxic to cells. Therefore, the cytotoxicity test was used for detection, and untreated cells were used as the control group.
The experiment was performed as follows.
(1) RD cells were plated in a 96-well plate at 100 μl per well.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum. Then, 3A-EP-DRI or 3A-EP-PEG4-PA was added to generate gradient concentrations of 0.01 μM, 0.1 μM, 1 μM, 10 μM, and 50 μM (final concentrations), respectively.
(3) The test was performed 24 hours after the addition of the polypeptide, and 10 μl of viable cell detection reagent CCK-8 was added to each well and mixed well.
(4) The plate was incubated at 37° C. for 2 h.
(5) The absorbance value at OD450 was measured with a microplate reader.
The results are shown in
RD cells were used to test the antiviral effect of polypeptides 3A-EP-DRI and 3A-EP-PEG4-PA. When RD cells reached 80% confluence, polypeptide 3A-EP-DRI or 3A-EP-PEG4-PA was added at concentrations of 0 μM (control group), 0.01 μM, 0.1 μM, 1 μM, 10 μM, and 50 μM, respectively. Three parallel wells were used for each concentration. The test was carried out 24 hours later, and the cell viability was detected using the CCK-8 kit. The results showed that there was no significant difference in the cell survival rate between the group added with 50 μM polypeptide 3A-EP-DRI or 3A-EP-PEG4-PA and the control group, indicating that polypeptides 3A-EP-DRI and 3A-EP-PEG4-PA are not toxic to cells within 50 μM.
Total RNA extraction kit (Omega), 24-well plate, 100 mm dish, and 50 ml syringe, 0.22 μm filter membrane (Millipore), one step qRT-PCR kit (Takara) were purchased in the market. The water used in the RNA extraction and qRT-PCR was DEPC-treated water, and the entire experiment was carried out in an RNase-free environment.
(1) RD cells were plated in five 100 mm dishes.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum. Then, 1 μl EV71 virus at 10{circumflex over ( )}7 PFU/ml was added, respectively.
(3) After 2 days, the cells were observed to see if the CPE phenomenon occurred. When the changes were obvious, samples were collected as follows.
(4) The supernatant in the 100 mm dish was transferred into a 15 ml centrifuge tube, and centrifuged at 500 g for 5 min.
(5) The supernatant was transferred into a new 15 ml centrifuge tube, and filtered through 0.22 μm filter membrane with a 50 ml syringe.
(6) RNA was extracted from 100 μl of the supernatant obtained in step (5) and subjected to one step qRT-PCR to measure the virus titer, and the previously extracted virus RNA with known titer was handled together as a control.
(1) Different cells were plated in 24-well cell plates.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum (0.5 ml/well), and 5 μl of 10{circumflex over ( )}6 PFU/mL EV71 virus per well were added.
(3) After 1 h, different polypeptides were added at a final concentration of 0.01 μM, 0.1 μM, 1 μM and 10 μM, respectively. Wells without treatment were used as control.
(4) Samples were collected 24 hours after virus infection, and RNA was extracted with total RNA extraction kit as follows.
(5) The supernatant in the wells was discarded, then 350 μl of TRK Lysis Buffer was added to each well and the plate was shaken on the shaker for 5 minutes.
(6) 350 μl of 70% ethanol (DEPC-treated) was added to the well and the plate was shaken on the shaker for 5 minutes.
(7) The mixture in the well was transferred to a RNA extraction column and centrifuged at 12000 g for 1 min.
(8) The solution collected in the recovery tube was added back to the column and centrifuged at 12,000 g for 1 min.
(9) RNA washing buffer 1 was added to the column and centrifuged at 12,000 g for 30s.
(10) RNA washing buffer 2 was added to the column and centrifuged at 12,000 g for 1 min.
(11) Step (10) was repeated once.
(12) The column was centrifuged at 12,000 g for 2 min to completely remove residual RNA washing buffer.
(13) 50 μl DEPC-treated H2O was added to the column and centrifuge at 12,000 g for 2 min.
(14) 2 μl RNA sample was used according to one step qRT-PCR kit for fluorescence quantification experiment.
The test results of polypeptides EP-PA, EP-CHOL, 3A-EP-DRI and 3A-EP-PEG4-PA are shown in
RD cells were used to test the antiviral effect of polypeptides EP-PA, EP-CHOL, 3A-EP-DRI and 3A-EP-PEG4-PA. EV71 virus was added to RD cells at 80% confluence (MOI=0.1). After 1 hour of infection, polypeptides EP-PA, EP-CHOL, 3A-EP-DRI or 3A-EP-PEG4-PA was added at concentrations of 0.01 μM, 0.1 μM, 1 μM, and 10 μM, respectively. The samples were collected 24 hours later, and the total cell RNA was extracted. The level of viral genomic RNA was measured by qRT-PCR. The cells infected with virus but without polypeptide treatment were used as a control group. The results show that all polypeptides have anti-EV71 activity, and increasing the polypeptide concentration significantly inhibits the expression level of viral RNA.
The results of anti-CVA16 virus effect of polypeptides P2, ER and ER-DRI are shown in
RD cells were used to test the antiviral effect of polypeptides P2, ER and ER-DRI, and penetrating peptide R8 and TAT were used as controls. EV71 was added to RD cells at 80% confluence (MOI=0.1). After 1 hour of infection, polypeptides P2, ER, ER-DRI, R8 or TAT was added at concentrations of 0.15625 μM, 0.3125 μM, 0.625 μM, 1.25 μM, 2.5 μM, and 5 μM, respectively. The CCK-8 kit was used to test the inhibitory activity of the polypeptide against the virus 24 hours after infection. Inhibition rate of polypeptide=(OD well with treatment−OD well with virus only)×100%/(OD well without treatment−OD well with virus only), OD refers to the value of OD450-OD630. The results show that the peptides P2, ER, and ER-DRI can significantly inhibit CVA16, while the penetrating peptide R8 and TAT have no effect on the virus. The IC50 of P2 is 1.533 μM, the IC50 of ER is 3.211 μM, and the IC50 of ER-DRI is 0.856 μM.
Test Antiviral Activity of Polypeptide P1 against EV71 and CVA16 in Mice
P1 (sequence: RRRRRRRRAISDLLAS) was commercially synthesized. Newborn 2-day-old ICR suckling mice were used in the experiment.
(1) 8 2-day-old ICR mice were randomly divided into two groups, 4 in each group. The 8 mice were administered EV71 by intraperitoneal injection at a dose of 108 PFU/ml.
(2) At the same time, one group was intraperitoneally injected with 10 mg/kg of polypeptide P1 as a treatment group, and the other group was intraperitoneally injected with an equal amount of PBS as a control group.
(3) Polypeptide and PBS were injected every 12 h for 5 days.
(4) At the fifth day, the mice were euthanized, and their hind limb muscle tissues were collected and triturated with Trizol (Invitrogen) to extract total RNA.
(5) Fluorescence quantification experiments were performed using a one step qRT-PCR kit.
The results are shown in
The results are shown in
Detection of Antiviral Activity of Polypeptide CR against EV71 in RD Cells
(1) RD cells in good growth state were plated in a 96-well plate.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum. Group without polypeptide and virus, and group with virus but without polypeptide were included as controls. The final virus concentration was 0.1 MOI.
(3) 1 h later, polypeptide CR at a final concentration of 5 μM, 2.5 μM, 1.25 μM, 0.625 μM, 0.3125 μM, and 0.15625 μM was added, respectively. Group without polypeptide and virus, and group with virus but without polypeptide were set as controls.
(4) 24 hours after virus infection, when the change in the control group with only virus was obvious, 10 μl of viable cell detection agent CCK-8 was added to each well and mixed well.
(5) The plate was incubated at 37° C. for 2 h.
(6) The absorbance value at OD450 was measured with a microplate reader. Inhibition rate of polypeptide=(OD well with treatment−OD well with virus only)×100%/(OD well without treatment−OD well with virus only), OD refers to the value of OD450-OD630.
The results are shown in
Antiviral Activity of Polypeptide CR against EV71 and CVA16 in Mice
Polypeptide CR (sequence: YGRKKRRQRRRGSGCR) was commercially synthesized. Newborn 2-day-old ICR suckling mice were used in the experiment.
(1) 8 2-day-old ICR mice were randomly divided into two groups, 4 in each group. The 8 mice were administered EV71 by intraperitoneal injection at a dose of 108 PFU/ml.
(2) At the same time, one group was intraperitoneally injected with 10 mg/kg of polypeptide CR as a treatment group, and the other group was intraperitoneally injected with an equal amount of PBS as a control group.
(3) Polypeptide and PBS were injected every 12 h for 5 days.
(4) At the fifth day, the mice were euthanized, and their hind limb muscle tissues were collected and triturated with Trizol (Invitrogen) to extract total RNA.
(5) Fluorescence quantification experiments were performed using a one step qRT-PCR kit.
The results are shown in
The results are shown in
Polypeptide ER-DRI was commercially synthesized. Newborn 2-day-old ICR suckling mice were used.
(1) A total of 12 10-day-old suckling mice were randomly divided into two groups, 6 in each group. One group was intraperitoneally injected with 20 mg/kg ER-DRI once daily for 3 consecutive days, and the other group was injected with an equal amount of PBS as a control.
(2) The body weight of the mice was recorded daily for a total of 15 days.
(3) Four weeks after the administration, the mice were euthanized and dissected, and the brain, liver, lung, and kidney were collected for HE staining.
The results are shown in
CCK-8 reagent was purchased from MCE.
Polypeptides ER and ER-DRI were desired to be able to inhibit viruses, and also to be non-toxic to cells. Therefore, the cytotoxicity test was used for detection, and untreated cells were used as the control group.
The experiment was performed as follows.
(1) RD cells were plated in a 96-well plate at 100 μl per well.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum. Then, polypeptide ER or ER-DRI was added to generate gradient concentrations of 0.46 μM, 2.34 μM, 4.68 μM, 9.37 μM, 18.75 μM, 37.5 μM, 75 μM, 150 μM, 300 μM (final concentrations), respectively.
(3) The test was performed 24 hours after the addition of the polypeptide, and 10 μl of viable cell detection reagent CCK-8 was added to each well and mixed well.
(4) The plate was incubated at 37° C. for 2 h.
(5) The absorbance value at OD450 was measured with a microplate reader.
The results are shown in
Detection of Antiviral Activity of ER and ER-DRI against EV71 in RD Cells
Total RNA extraction kit (Omega), 24-well plate, 100 mm dish, and 50 ml syringe, 0.22 μm filter membrane (Millipore), one step qRT-PCR kit (Takara) were purchased in the market. The water used in the RNA extraction and qRT-PCR was DEPC-treated water, and the entire experiment was carried out in an RNase free environment.
(1) RD cells in good growth state were plated in a 96-well plate.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum. Group without polypeptide and virus, and group with virus but without polypeptide were included as controls. The final virus concentration was 0.1 MOI.
(3) 1 h later, polypeptide CR at a final concentration of 2.5 μM, 1.25 μM, 0.625 μM, 0.3125 μM, and 0.15625 μM was added, respectively. Group without polypeptide and virus, and group with virus but without polypeptide were set as controls.
(4) 24 hours after virus infection, when the change in the control group with only virus was obvious, 10 μl of viable cell detection agent CCK-8 was added to each well and mixed well.
(5) The plate was incubated at 37° C. for 2 h.
(6) The absorbance value at OD450 was measured with a microplate reader. Inhibition rate of polypeptide=(OD well with treatment−OD well with virus only)×100%/(OD well without treatment−OD well with virus only), OD refers to the value of OD450-OD630.
The results are shown in
Detection of Antiviral Activity of ER-DRI against EV71 in Mice
Polypeptide ER-DRI was commercially synthesized. 10 2-day-old suckling mice were used.
(1) 10 2-day-old ICR mice were randomly divided into two groups, 5 in each group. The 10 mice were administered with EV71 by intraperitoneal injection at a dose of 108 PFU/ml.
(2) At the same time, one group was intraperitoneally injected with 10 mg/kg of polypeptide ER-DRI as a treatment group, and the other group was intraperitoneally injected with an equal amount of PBS as a control group.
(3) Polypeptide and PBS were injected every 12 h for 5 days.
(4) At the fifth day, the mice were euthanized, and their lung tissues were collected and triturated with Trizol (Invitrogen) to extract total RNA.
(5) Fluorescence quantification experiments were performed using a one step qRT-PCR kit.
The results are shown in
CCK-8 reagent was from MCE.
Polypeptides BP8, BP10 and BP15 were desired to be able to inhibit viruses, and also to be non-toxic to cells. Therefore, the cytotoxicity test was used for detection, and untreated cells were used as the control group.
The experiment was performed as follows.
(1) RD cells were plated in a 96-well plate at 100 μl per well.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum. Then, polypeptide BP8, BP10 or BP15 was added to generate gradient concentrations of 3.0625 μM, 6.125 M, 12.5 μM, 25 μM, 50 μM, 100 μM, and 200 μM (final concentrations), respectively.
(3) The samples were collected 24 hours after the addition of the polypeptide, and 10 μl of live cell detection reagent CCK-8 was added to each well and mixed well.
(4) The plate was placed at 37° C. for 4 h.
(5) The absorbance value at OD450 was measured with a microplate reader.
The results are shown in
CCK-8 reagent was from MCE.
Polypeptides BP8, BP10 and BP15 were desired to be able to inhibit viruses, and also to be non-toxic to cells. Therefore, the cytotoxicity test was used for detection, and untreated cells were used as the control group.
The experiment was performed as follows.
(1) Vero cells were plated in a 96-well plate at 100 μl per well.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum. Then, polypeptide BP8, BP10 or BP15 was added to generate gradient concentrations of 3.0625 μM, 6.125 M, 12.5 μM, 25 μM, 50 μM, 100 μM, and 200 μM (final concentrations), respectively.
(3) The samples were collected 24 hours after the addition of the polypeptide, and 10 μl of live cell detection reagent CCK-8 was added to each well and mixed well.
(4) The plate was placed at 37° C. for 4 h.
(5) The absorbance value at OD450 was measured with a microplate reader.
The results are shown in
Test Antiviral Effect of Polypeptides BP8, BP10 and BP15 against CVB5 in RD Cells
Polypeptides BP8 (shown as SEQ ID NO: 12), BP10 (shown as SEQ ID NO: 13), and BP15 (shown as SEQ ID NO: 14) were all commercially synthesized.
(1) DR cells were plated in a 24-well cell plate.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum (0.5 ml/well). CVB5 viruses were added at MOI=0.01, and the group without CVB5 as control.
(3) After 1 h, polypeptides BP8, BP10 or BP15 was added at a final concentration of 0.78 μM, 1.56 μM, 3.13 μM and 6.25 μM, respectively.
(4) Samples were collected 24 hours after virus infection, and RNA was extracted with total RNA extraction kit as follows.
(5) The supernatant in the wells was discarded, then 350 μl of TRK Lysis Buffer was added to each well and the plate was shaken on the shaker for 5 minutes.
(6) 350 μl of 70% ethanol (DEPC-treated) was added to the well and the plate was shaken on the shaker for 5 minutes.
(7) The mixture in the well was transferred to a RNA extraction column and centrifuged at 12000 g for 1 min.
(8) The solution collected in the recovery tube was added back to the column and centrifuged at 12000 g for 1 min.
(9) RNA washing buffer 1 was added to the column and centrifuged at 12,000 g for 30s.
(10) RNA washing buffer 2 was added to the column and centrifuged at 12,000 g for 1 min.
(11) Step (10) was repeated once.
(12) The column was centrifuged at 12,000 g for 2 min to completely remove residual RNA washing buffer.
(13) 50 μl DEPC-treated H2O was added to the column and centrifuge at 12,000 g for 2 min.
(14) 2 μl RNA sample was used according to one step qRT-PCR kit for fluorescence quantification experiment.
The results are shown in
Test Antiviral Effect of Polypeptide BP8 against CVB3 in Vero Cells
Polypeptides BP8 (shown as SEQ ID NO: 12) was commercially synthesized.
(1) Vero cells were plated in a 24-well cell plate.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum and CVB3 virus, 0.5 ml per well. MOI of the virus was 0.01. Wells without CVB3 virus was set as control group.
(3) After 1 h, polypeptide BP8 was added at a final concentration of 0.25 μM, 0.5 μM and 10 μM, respectively.
(4) Samples were collected 24 hours after virus infection, and RNA was extracted with total RNA extraction kit as follows.
(5) The supernatant in the wells was discarded, then 350 μl of TRK Lysis Buffer was added to each well and the plate was shaken on the shaker for 5 minutes.
(6) 350 μl of 70% ethanol (DEPC-treated) was added to the well and the plate was shaken on the shaker for 5 minutes.
(7) The mixture in the well was transferred to a RNA extraction column and centrifuged at 12000 g for 1 min.
(8) The solution collected in the recovery tube was added back to the column and centrifuged at 12000 g for 1 min.
(9) RNA washing buffer 1 was added to the column and centrifuged at 12,000 g for 30s.
(10) RNA washing buffer 2 was added to the column and centrifuged at 12,000 g for 1 min.
(11) Step (10) was repeated once.
(12) The column was centrifuged at 12,000 g for 2 min to completely remove residual RNA washing buffer.
(13) 50 μl DEPC-treated H2O was added to the column and centrifuge at 12000 g for 2 min.
(14) 2 μl RNA sample was used according to one step qRT-PCR kit for fluorescence quantification experiment.
The results are shown in
Test Antiviral Effect of Polypeptide BP8 against CVB5 in Mice
1. Materials: Polypeptide BP8 (shown as SEQ ID NO: 12) was commercially synthesized. 10 2-day-old ICR suckling mice were used.
2. Antiviral activity of peptide BP8 in mice
(1) 10 2-day-old ICR suckling mice were randomly divided into two groups, 5 in each group. The 10 suckling mice were challenged by intraperitoneal injection of CVB5 at a dose of 108 PFU/ml.
(2) At the same time, one group was intraperitoneally injected with 10 mg/kg of polypeptide BP8 as a treatment group, and the other group was intraperitoneally injected with an equal amount of PBS as a control group.
(3) Polypeptide and PBS were injected every 12 h for 5 days.
(4) At the fifth day, the mice were euthanized, and their hind limb muscle tissues were collected and triturated with Trizol (Invitrogen) to extract total RNA.
(5) Fluorescence quantification experiments were performed using a one step qRT-PCR kit.
The results are shown in
Detection of Antiviral Effect of Polypeptide ER-DRI against CVA6 in Vero Cells
Polypeptide ER-DEI (SEQ ID NO: 11) was commercially synthesized.
(1) Vero cells were plated in a 24-well cell plate.
(2) After the cells reached 70%-80% confluence, the MEM medium containing 10% serum was replaced with a MEM medium containing 2% serum and CVA6 virus, 0.5 ml per well. MOI of the virus was 0.01. The wells without CVA6 virus was set as control group.
(3) After 1 h, polypeptide ER-DRI was added at a final concentration of 2.5 μM, 5 μM and 10 μM, respectively.
(4) Samples were collected 24 hours after virus infection, and RNA was extracted with total RNA extraction kit as follows.
(5) The supernatant in the wells was discarded, then 350 μl of TRK Lysis Buffer was added to each well and the plate was shaken on the shaker for 5 minutes.
(6) 350 μl of 70% ethanol (DEPC-treated) was added to the well and the plate was shaken on the shaker for 5 minutes.
(7) The mixture in the well was transferred to a RNA extraction column and centrifuged at 12000 g for 1 min.
(8) The solution collected in the recovery tube was added back to the column and centrifuged at 12000 g for 1 min.
(9) RNA washing buffer 1 was added to the column and centrifuged at 12,000 g for 30s.
(10) RNA washing buffer 2 was added to the column and centrifuged at 12,000 g for 1 min.
(11) Step (10) was repeated once.
(12) The column was centrifuged at 12,000 g for 2 min to completely remove residual RNA washing buffer.
(13) 50 μl DEPC-treated H2O was added to the column and centrifuge at 12,000 g for 2 min.
(14) 2 μl RNA sample was used according to one step qRT-PCR kit for fluorescence quantification experiment.
The results are shown in
The polypeptides and application thereof provided by the present invention are described in detail above. The principles and embodiments of the present invention have been described with reference to specific examples, and the description of the above embodiments is only to assist in understanding the method of the present invention and the core idea thereof. It should be noted that those skilled in the art can make various modifications and changes to the present invention without departing from the spirit and scope of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201810056297.1 | Jan 2018 | CN | national |
This application is the National Stage of Application No. PCT/CN2019/072455, filed Jan. 21, 2019, which claims the priority of Chinese patent application No. 2018100562971 filed with the Chinese Patent Office on Jan. 20, 2018, entitled “INHIBITOR OF ENTEROVIRUS 71 AND APPLICATION THEREOF”, each of which is incorporated herein by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CN2019/072455 | 1/21/2019 | WO |
