A polypeptide RVA6 with anti-nervous system injury and neuroprotective effects and its application

Abstract

The present invention discloses a polypeptide RVA6 having anti - nervous system injury and neuroprotective effects and its applications. The amino acid sequence of the polypeptide RVA6 is shown as SEQ ID NO.1. The polypeptide RVA6 of the present invention is a new structural polypeptide compound that is commercially synthesized and has its activity identified, which can stabilize the DR region of the NKAα1 subunit. The polypeptide RVA6 has low toxicity and good application prospects. The polypeptide RVA6 can increase the cell survival rate of the in vitro model of PD at a relatively low concentration, inhibit the generation of reactive oxygen species, relieve autophagic disorders and ferroptosis processes, and has the effect of anti - nerve injury. The polypeptide RVA6 can improve the behavioral disorders and pathological characteristics of model animals with PD and depression, has neuroprotective effects, is easy to synthesize, and is easy to prepare in large quantities.

Description

Technical Field

[0001] The present invention relates to the fields of drugs and health products, and particularly relates to a polypeptide RVA6 having anti-nervous system injury and neuroprotective effects and its applications. Background Art

[0002] According to statistics of the World Health Organization, nervous system injury diseases are the second leading cause of human death. Parkinson's disease (PD), Alzheimer's disease, depression, multiple sclerosis, etc. are common nervous system injury diseases. The clinical treatment drugs for nervous system injury diseases have many adverse reactions such as large individual differences, slow onset, and withdrawal rebound, and currently there is a lack of effective drugs for repairing nerve function after central nervous system injury. Polypeptides have good biocompatibility, strong specificity, low toxicity, are not likely to accumulate in the body, and have few interactions with other components, but they have the defect of being easily inactivated by enzymatic hydrolysis, which limits the clinical application of polypeptide drugs.

[0003] Sodium-potassium ATPase (Na + / K + -ATPase, NKA) is a transmembrane protein expressed in all cells, which can exchange three sodium ions for two potassium ions into the cell. NKA consists of three subunits, α, β, and γ, and the α subunit has four catalytic subtypes (α 1-4 ). It has been reported in the literature that the polyclonal antibody against the DR region of the NKAα1 subunit (DR-Ab) has the effects of anti-aggregation of the PD pathogen α-synuclein (α-Syn) and promoting the recovery of nerve function after cerebral ischemia injury, but the active ingredient that plays its neuroprotective role is not yet clear.

[0004] The existing clinical treatment drugs for nervous system injury diseases have many adverse reactions such as large individual differences, slow onset, and withdrawal rebound, and currently there is a lack of effective drugs for repairing nerve function after central nervous system injury. Summary of the Invention

[0005] In view of the defects in the prior art, the present invention provides a polypeptide RVA6 having anti-nervous system injury and neuroprotective effects and its applications.

[0006] The present invention provides a polypeptide RVA6 having anti-nervous system injury and neuroprotective effects, and the amino acid sequence of the RVA6 polypeptide is shown in SEQ ID NO.1.

[0007] The present invention also provides the application of the RVA6 polypeptide in the preparation of products for treating or assisting in the treatment of nervous system injury diseases.

[0008] Further, the nervous system injury diseases include, but are not limited to, Parkinson's disease and depression.

[0009] Further, the product is a drug or a health care product.

[0010] Further, the product includes a therapeutically effective dose of RVA6 polypeptide and a pharmaceutically acceptable excipient.

[0011] Further, the dosage form of the product is selected from any one of injection, tablet, powder for injection, controlled-release capsule, liposome nanoparticle, granule or dropping pill.

[0012] Further, the effective dose of RVA6 polypeptide is 100 - 400 μM.

[0013] The present invention also provides a pharmaceutical composition comprising the RVA6 polypeptide as an active ingredient and a pharmaceutically acceptable excipient.

[0014] Further, the dosage form of the pharmaceutical composition is selected from any one of injection, tablet, powder for injection, controlled-release capsule, liposome nanoparticle, granule or dropping pill.

[0015] Further, the effective dose of RVA6 polypeptide is 100 - 400 μM.

[0016] In summary, compared with the prior art, the present invention achieves the following technical effects:

[0017] The polypeptide RVA6 of the present invention is a new structural polypeptide compound with a stable NKAα1 subunit DR region that is commercially synthesized and has its activity identified. The polypeptide RVA6 has low toxicity and good application prospects. The polypeptide RVA6 can improve the cell viability of the PD in vitro model at a lower concentration, inhibit the generation of reactive oxygen species (ROS), relieve autophagy disorders and ferroptosis processes, and has the effect of anti-neural injury. The polypeptide RVA6 can improve the behavioral disorders and pathological characteristics of PD and depression model animals, has a neuroprotective effect, and is easy to synthesize and mass-produce. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the present invention, and thus should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1It is the result analysis diagram of the influence of polypeptide RVA6 on the survival rate of SH-SY5Y nerve cells after 6-OHDA stimulation in Example 1 of the present invention.

[0020] Figure 2 It is the result analysis diagram of the influence of polypeptide RVA6 on the protein expression of NKAα1 subunit in SH-SY5Y nerve cells after MPP+ stimulation in Example 2 of the present invention.

[0021] Figure 3 It is the result analysis diagram of the influence of polypeptide RVA6 on the mitochondrial function of SH-SY5Y nerve cells after MPP+ stimulation in Example 3 of the present invention.

[0022] Figure 4 It is the result analysis diagram of the influence of polypeptide RVA6 on the ferroptosis level of SH-SY5Y nerve cells after MPP+ stimulation in Example 4 of the present invention.

[0023] Figure 5 It is the result analysis diagram of the influence of polypeptide RVA6 on the neurobehavior of PFF model mice in Example 5 of the present invention.

[0024] Figure 6 It is the result analysis diagram of the influence of polypeptide RVA6 on the neurobehavior of CMS model mice in Example 6 of the present invention.

[0025] Figure 7 It is the result analysis diagram of the influence of polypeptide RVA6 on the number and morphology of neuronal synapses in the hippocampus of CMS model mice in Example 7 of the present invention. Detailed implementation manners

[0026] In order to enable those skilled in the art to better understand the solution of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] Example 1 Influence of polypeptide RVA6 on the viability of SH-SY5Y nerve cells after 6-OHDA stimulation

[0028] (1) Cell culture

[0029] The SH-SY5Y cells were cultured in an 8-cm culture dish with a medium containing 10% FBS, 1×10 5Cultured in DMEM medium containing 100 U / mL penicillin and 100 mg / L streptomycin, and placed in a cell incubator at 37°C and 5% CO2. The medium was changed every other day. When the cell confluence reached about 80%, the cells were digested with 0.25% trypsin and passaged. Cells in the logarithmic growth phase were selected for the following experiments.

[0030] (2) Establishment and evaluation of the 6-OHDA-induced PD in vitro injury model

[0031] Cells in the logarithmic growth phase were seeded at a density of 8×10 3 cells per well in a 96-well plate and cultured in a cell incubator for 24 h. After the cells were completely adherent, a control group, a 6-OHDA treatment group (200 μM, 24 h), and treatment groups with different concentrations of polypeptide RVA6 (final concentrations of 100, 200, and 400 μM) were set up. Each group had 5 replicate wells, and the above experiments were repeated 3 times. The cell morphology was observed under an inverted microscope, and the cell viability was detected by the CCK-8 method to evaluate the success of the model establishment.

[0032] (3) Detection of cell survival rate by CCK-8 method

[0033] After the cells were completely adherent, according to the grouping, treatment groups with different concentrations of polypeptide RVA6 (final concentrations of 100, 200, and 400 μM) were added first for pretreatment for 2 h, and then 200 μM 6-OHDA was added for continued culture for 24 h. A control group (only adding the culture medium) and a model group (only adding the culture medium and 200 μM 6-OHDA) were set up, and each group had 5 replicate wells. After continued culture for 24 h, 10 μL of CCK-8 solution was added to each well, and the mixture was incubated at 37°C in the dark for 2 h. The absorbance (A) of each well was detected at an excitation wavelength of 450 nm using an enzyme-linked immunosorbent assay (ELISA) reader, and the relative viability of the cells in each group was calculated. The relative cell viability (%) = (A of the drug-treated group - A of the control group) / (A of the non-drug-treated group - A of the control group) × 100%. The above experiments were repeated 5 times.

[0034] The test results are as Figure 1 shown. Polypeptide RVA6 at 100, 200, and 400 μM all increased the viability of 6-OHDA-damaged cells. Therefore, the pharmacological effects of polypeptide RVA6 were further studied in subsequent experiments.

[0035] Example 2 Effect of polypeptide RVA6 on the protein expression of NKAα1 subunit in SH-SY5Y neurons after MPP + stimulation

[0036] (1) Cell culture and grouping

[0037] SH-SY5Y cells were placed in high-glucose DMEM medium containing 10% fetal bovine serum and 1% penicillin-streptomycin, and cultured in an incubator at 37 °C and 5% CO2. When the cell confluence reached 80%, passage was carried out, and cells in the logarithmic growth phase were selected for the experiment. The cells were divided into a control group (cultured normally without any reagent intervention), an MPP + group (500 μM, 24 h), and an MPP + +RVA6 group (cells were pretreated with 200 μM RVA6 for 2 h and then treated with 500 μM MPP + for 24 h).

[0038] (2) Detection of the protein expression of NKAα1 subunit in cells by Western blot

[0039] Cells from each group were collected, washed with pre-cooled PBS, 100 μL of cell lysate was added, and incubated on ice for 30 min to extract the total protein of each group of cells. The protein content of each group was determined by the BCA method. The proteins were denatured, electrophoresed by SDS-PAGE, transferred to a membrane by wet transfer, and blocked with 5% skim milk for 1 h. Primary antibodies (NKAα1 1:200, P-cadherin 1:1000) were added and incubated overnight on a shaker at 4 °C. After washing with TBST, secondary antibody (1:1000) was added and incubated at room temperature for 1 h. After washing with TBST, ECL was used for development and imaging.

[0040] The test results were as Figure 2 shown. Pretreatment with the polypeptide RVA6 could restore the down-regulated protein expression of NKAα1 in SH-SY5Y cells induced by MPP + .

[0041] Example 3 Effect of polypeptide RVA6 on the mitochondrial function of SH-SY5Y neurons after MPP + stimulation

[0042] (1) Determination of the intracellular ROS level using the dihydroethidium (DHE) fluorescent probe

[0043] SH-SY5Y cells in the logarithmic growth phase were seeded into 6-well plates at a density of 2×10 5 cells per well. After culturing for 24 h, drug treatment intervention was carried out. The grouping and treatment were the same as in "Example 2". After 24 h of intervention, 5 μM of DHE probe was added to the cells in each group, and incubated at 37 °C for 30 min. The probe was removed, and the cells were washed twice with phosphate buffered solution (PBS), and observed and photographed using a fluorescence inverted microscope. The level of cellular oxidative stress was evaluated by the intracellular ROS content (i.e., the intensity of red fluorescence).

[0044] (2) Detection of the expression levels of p62, parkin, and TOM20 proteins in cells by Western blot

[0045] The grouping and treatment were the same as in "Example 2". The dilution ratios of the primary antibodies were as follows: p62 1:1000, parkin 1:1000, TOM20 1:1000, and β-actin 1:1000.

[0046] The experimental results were as Figure 3 shown. The polypeptide RVA6 reduced the content of ROS in SH-SY5Y cells after MPP + stimulation ( Figure 3 A) and improved the mitochondrial autophagy disorder in SH-SY5Y cells ( Figure 3 B).

[0047] Example 4 Effect of polypeptide RVA6 on the ferroptosis level of SH-SY5Y neurons after MPP + stimulation

[0048] (1) Detection of the expression level of SLC7A11 protein in cells by Western blot

[0049] The grouping and treatment were as described in "Example 2". The dilution ratios of the primary antibodies were as follows: SLC7A11 1:1000 and β-actin 1:1000.

[0050] The experimental results were as Figure 4 shown. The polypeptide RVA6 alleviated the ferroptosis level of SH-SY5Y cells after MPP + stimulation.

[0051] Example 5 Effect of polypeptide RVA6 on the neurobehavior of PFF model mice

[0052] (1) Experimental animals and main reagents

[0053] Experimental animals: SPF-grade male C57BL / 6 mice, 8 weeks old, weighing (20 ± 2) g, were housed in a clean environment with free access to water and food, at a room temperature of (19 ± 2) °C, a humidity of (50 ± 5)%, and a 12h / 12h light-dark cycle. Main reagents: α-syn was purchased from rPeptide Company, USA.

[0054] (2) Animal grouping and treatment

[0055] Thirty experimental mice were randomly divided into a PBS group, a PFF group, and a PFF + peptide group, where peptide represents the polypeptide RVA6, with 10 mice in each group. The mice were anesthetized with isopentane and fixed on a stereotaxic apparatus. The dorsal skin of the mouse's skull was incised, and the surface of the skull was wiped with a 0.03% hydrogen peroxide solution until the cranial sutures and anterior and posterior fontanelles were clearly visible. After determining the coordinates (the stereotaxic coordinates of the right lateral ventricle were 0.3 mm posterior to the anterior fontanelle, 1 mm to the right, and 2.2 mm deep), a cannula 5.2 mm long was vertically implanted into the lateral ventricle 2.2 mm. PBS or α-syn 2 μL was injected at a flow rate of 1 μL / min once a day for 7 consecutive days. Mice in the PFF + peptide group were intraperitoneally injected with a single dose of 200 μg of RVA6 once a week for 4 consecutive weeks.

[0056] (3) Morris water maze experiment

[0057] The water maze had a diameter of 120 cm and a height of 45 cm, filled with 25 cm of water, and was divided into four quadrants (designated as N, S, E, and W areas). A circular escape platform with a diameter of 12 cm was fixed 1 cm below the water surface in the target quadrant. The place navigation experiment was conducted for 5 consecutive days, with 4 training sessions at a fixed time period each day, and a 1-hour interval between each experiment. The mice were randomly placed into the water from one of the four quadrants to search for the underwater escape platform. Each test lasted 90 s. When the mouse reached the underwater platform, the experiment ended. Whether the mouse found the platform within 90 s or not, it was placed on the platform to rest for 30 s before the next experiment. The time (escape latency) for the mouse to find the platform and the distance swum (escape distance) were collected and recorded by video equipment, and the average of the 4 training sessions of the mouse each day was taken as the score. On the 6th day, the platform was removed to conduct the spatial probe experiment. The mouse was placed into the water from a fixed position, and the number of times the original platform was crossed and the time spent staying in the original platform area within 120 s were recorded.

[0058] (4) Rotarod test

[0059] After the mice were adapted to the rotarod for 2 min, the rotation speed of the rotarod was set to 4 - 40 r / min to allow the mice to move autonomously with the rotarod, and the time the mice spent moving on the rotarod was recorded. Two measurements were taken (with a 30-min interval) and the average was calculated.

[0060] The test results are shown in the figure. The swimming trajectory diagram of the mice shows that ( Figure 5 A) The polypeptide RVA6 significantly prolonged the time the PFF model mice spent staying in the original platform area ( Figure 5 B), increased the number of times the model mice crossed the platform ( Figure 5 C), and at the same time restored the rotarod staying time of the model mice ( Figure 5D). That is, polypeptide RVA6 improves the PD-like behavioral disorders in mice with the PFF model.

[0061] Example 6 Effects of polypeptide RVA6 on neurobehavior in mice with the CMS model

[0062] (1) Experimental animals

[0063] Same as "Example 5".

[0064] (2) Animal grouping and treatment

[0065] Forty experimental mice were randomly divided into an IgG group, a peptide group, a CMS + IgG group, and a CMS + peptide group, with 10 mice in each group. Here, peptide represents polypeptide RVA6. Among them, CMS lasted for 6 weeks, and the treatment method for the mice in the dosing groups was the same as that in "Example 2". After the model was established, IgG or peptide was injected into the lateral ventricle at a flow rate of 1 μL / min at a dose of 2 μL / 30 μg per mouse, and behavioral tests were performed 2 h later.

[0066] (3) Construction of the CMS model

[0067] All mice were housed individually in cages. Among them, the mice in the model group were subjected to stress operations such as fasting and water deprivation for 12 h, wet bedding for 6 h, cage tilt at 45°C for 2 h, cold water swimming at 4°C for 5 min, tail clamping (about 1 cm from the base of the mouse's tail) for 1 min, restraint in a 50 mL volume breathable restraint tube for 2 h, and circadian rhythm reversal. One type of stress or multiple stresses were used daily, and the same stress method could not appear continuously to prevent the mice from predicting the occurrence of stress and avoid adaptation. At the same time, the body weight of all mice (from 9:00 to 11:00) and the sucrose preference rate (from 20:00 to 22:00 and from 8:00 to 10:00 the next day) were measured weekly. The model period was 6 weeks.

[0068] (4) Sucrose preference test

[0069] It is used to reflect the anhedonic behavior of depressed animals. A horizontal placement of water bottles containing 1% sucrose solution and distilled water was placed on the mouse cage; the positions of the two water bottles were exchanged every 6 h to prevent the mice from developing position memory and preference. The amounts of sucrose solution and distilled water ingested by the mice within 24 h were recorded, and the sucrose preference rate (sucrose intake / total water intake) was calculated.

[0070] (5) Forced swimming test

[0071] Used to reflect the despair behavior of experimental mice. Before the experiment, the mice were trained to swim in warm water for 20 minutes, and tested the next day: The mice were placed into a transparent glass tank with a water temperature of 25°C and a water depth of 20 cm (height 30 cm, diameter 14 cm). Observe and record the locomotor behavior of the mice within 6 minutes, and use the Clever Sys Inc. system in the United States to calculate the time when the body and limbs of the mice remain completely motionless (floating) within the last 4 minutes.

[0072] (6) Tail suspension test

[0073] Used to reflect the despair behavior of experimental mice. The mice were hung upside down in a recording box with tape at a position 1 / 3 from the tip of the tail, observe and record the behavior of the mice within 6 minutes, and use the Clever Sys Inc. system in the United States to calculate the time when the body and limbs of the mice remain completely motionless within the last 4 minutes.

[0074] (7) Social approach-avoidance test

[0075] After the animals were adapted to the test room for 1 hour, the social approach-avoidance test was carried out. First, the animals were placed in a square open box of 50×50×50 cm and freely adapted for 5 minutes. During the test, an empty mouse cage was placed in one corner of the open box, and an identical mouse cage with a stimulus mouse was placed in the diagonal corner. There were round holes on the mouse cage, and the experimental mouse and the stimulus mouse could make olfactory contact. The experimental mouse was put into the open box, and the Etho Vision XT behavioral trajectory tracking system was used to record the time, frequency of the experimental mouse contacting the empty mouse cage and the stimulus mouse cage within 10 minutes, and the latency of the first contact with the mouse cage. After the experiment, the experimental mouse was taken out and returned to the cage. Preference index = time of the experimental mouse contacting the stimulus mouse cage / time of contacting the empty mouse cage. The contact behavior was manifested as active sniffing, which was defined as the range within 2 cm of the tip of the experimental mouse's nose from the mouse cage.

[0076] (8) Novelty feeding test

[0077] The mice were fasted for 24 hours before the test. At the start of the test, the mice were placed alone in a corner of a test box (length × width × height = 27 cm × 16 cm × 13 cm), and a 1-cm layer of wood shavings was laid on the bottom of the box, and 4 pieces of the usual food were placed in the middle. Record the latency of the mice feeding within 5 minutes.

[0078] (9) Open field test

[0079] Used to reflect the spontaneous activity behavior and exploratory behavior of mice, and evaluate the tension and anxiety of experimental animals in a novel environment. The mice were placed in an activity box (50×50×40 cm), observe and record the activity trajectories of the mice within 5 minutes, and use Open field software (Clever Sys Inc, VA, USA) to calculate the total number of times the mice entered the central area of the activity box and the residence time in the central area.

[0080] The test results are as Figure 6 shown, and polypeptide RVA6 significantly improves the sucrose preference rate of CMS mice ( Figure 6 A), reduces the immobility time of the model mice in the tail suspension and forced swimming tests ( Figure 6 B), shortens the latency of novel feeding and social interaction ( Figure 6 C and D), and restores their spontaneous locomotor activity in the open field ( Figure 6 E and F). That is, polypeptide RVA6 improves the depressive-like behavior of CMS model mice.

[0081] Example 7 Effect of polypeptide RVA6 on the number and morphology of neuronal synapses in the hippocampus of CMS model mice

[0082] (1) Experimental animals

[0083] Same as "Example 6".

[0084] (2) Animal grouping and treatment

[0085] Same as "Example 6".

[0086] (3) Construction of the CMS model

[0087] Same as "Example 6".

[0088] (4) Frozen sections

[0089] After the mice were anesthetized intraperitoneally with 0.25% Avertin, they were fixed on the operating table. The chest cavity was opened to expose the heart, and the heart was perfused with normal saline at room temperature. The perfusion was completed when the color of the perfusate gradually changed from dark red to light until it was colorless and transparent; the skin and dura mater of the mouse brain were cut open to expose the brain tissue, and the whole brain tissue was taken out and immersed in 4% paraformaldehyde solution for fixation for 48 h, and then dehydrated with gradient 20% and 30% sucrose solutions for 72 h each; the dehydrated brain tissue was taken out, blotted dry, embedded in OCT, and the cryostat was pre-cooled to -20 °C in advance. Sagittal sections were made with a thickness of 20 μm. Serial sections were started from the appearance of the hippocampal tissue, and 20 consecutive sections were made starting from the 8th section. The sections were pasted and preserved.

[0090] (5) Immunofluorescence

[0091] Take tissue sections from the same location, warm them to room temperature for 30 min, add 1% TritonX-100 solution to disrupt the membrane at room temperature for 30 min, wash 3 times with PBS, block with 3% BSA at room temperature for 1 h, wash 3 times with PBS, add the corresponding primary antibodies (MAP2 1:200; SYP 1:150; PSD95 1:100), evenly cover the brain slices, incubate overnight in a refrigerator at 4 °C, wash 3 times with PBS, add the secondary antibody and incubate in the dark at room temperature for 1 h, wash 3 times with PBS, add DAPI to stain the nuclei for 5 min, wash 3 times with PBS, drop anti-quenching agent, mount the slides and store, observe and take pictures under a microscope.

[0092] (6) Evaluate the number and morphology of neurons

[0093] Use a stereological system combined with Image J software to calculate the change in the protrusion length of neuronal dendrites (MAP2 + ), the density and quantity of the presynaptic membrane (SYP + ) and the postsynaptic membrane (PSD95 + ).

[0094] The experimental results are as Figure 7 shown. The polypeptide RVA6 significantly restores the damaged dendritic morphology and synaptic density of neurons in the hippocampal region of model mice ( Figure 7 A and 7B). That is, the polypeptide RVA6 reduces the loss of synaptic density and structural damage in the hippocampal region of CMS mice.

[0095] Based on the above examples, the present invention has been proven feasible through experiments. The experimental results are as follows:

[0096] (1) The polypeptide RVA6 of the present invention has low toxicity. At a concentration of 100 - 400 μM, no cytotoxicity is observed, and it has good application prospects.

[0097] (2) The polypeptide RVA6 of the present invention can increase the survival rate of SH-SY5Y nerve cells after 6-OHDA stimulation at a relatively low concentration, suggesting that it has a neuroprotective effect.

[0098] (3) The polypeptide RVA6 of the present invention can significantly inhibit the generation of reactive oxygen species (ROS) and relieve autophagy disorders in SH-SY5Y nerve cells after MPP + stimulation, suggesting that it has an effect of improving mitochondrial dysfunction.

[0099] (4) The polypeptide RVA6 of the present invention can significantly reduce the ferroptosis process of SH-SY5Y nerve cells after MPP + stimulation, suggesting that it has an effect of improving iron homeostasis imbalance.

[0100] (5) The polypeptide RVA6 of the present invention can significantly improve the neurobehavior of mice in the α-syn preformed fibrils (α-syn PFF) model, suggesting its role in anti-Parkinson's disease behavioral disorders.

[0101] (6) The polypeptide RVA6 of the present invention can improve the depressive-like behavior of mice in the Chronic mild stress (CMS) model, reduce the loss of neuronal synapses in the hippocampal region and alleviate dendritic morphological damage, suggesting that the polypeptide RVA6 can be used for the treatment of depression.

[0102] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

[0103] Sequence Listing SEQ ID NO.1 RVAPGGNRVLSSYYGKGGKDRF

Claims

1. A polypeptide RVA6 with anti - nervous system injury and neuroprotective effects, characterized in that, The amino acid sequence of the RVA6 polypeptide is shown in SEQ ID NO.

1.

2. Use of the RVA6 polypeptide according to claim 1 in the preparation of a medicament for treating or assisting in the treatment of diseases of nervous system injury; The diseases of nervous system injury are Parkinson's disease and depression.

3. The application according to claim 2, wherein The medicament comprises a therapeutically effective dose of the RVA6 polypeptide and a pharmaceutically acceptable excipient.

4. The application according to claim 2, wherein The dosage form of the medicament is selected from any one of injection, tablet, powder injection, controlled release capsule, liposome nanoparticle, granule or dropping pill.

5. The application according to claim 2, characterized in that, The effective dose of the RVA6 polypeptide is 100 - 400 μM.

6. A pharmaceutical composition, characterized in that, Comprising the RVA6 polypeptide according to claim 1 as an active ingredient and a pharmaceutically acceptable excipient.

7. The pharmaceutical composition according to claim 6, wherein, The dosage form of the pharmaceutical composition is selected from any one of injection, tablet, powder injection, controlled release capsule, liposome nanoparticle, granule or dropping pill.

8. The pharmaceutical composition according to claim 6, characterized in that, The effective dose of the RVA6 polypeptide is 100 - 400 μM.

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