CN112390877B

CN112390877B - PEDF-derived polypeptide composition and application thereof in preparation of lung injury protection drugs

Info

Publication number: CN112390877B
Application number: CN201910758301.3A
Authority: CN
Inventors: 董红燕; 秦西淳; 姜力群; 张中明; 陈佳丽; 刘志伟; 朱立东
Original assignee: Individual
Current assignee: Huarong (Xuzhou) Biomedical Technology Development Research Institute Co.,Ltd.
Priority date: 2019-08-16
Filing date: 2019-08-16
Publication date: 2022-10-04
Anticipated expiration: 2039-08-16
Also published as: CN112390877A

Abstract

The invention discloses a PEDF-derived polypeptide composition and application thereof in preparing a medicament for protecting lung injury, wherein the PEDF-derived polypeptide composition is prepared from a polypeptide shown in SEQ ID NO:2 and the 34 amino acid sequence peptide shown in SEQ ID NO:3, and the 44 amino acid sequence peptide shown in the figure. The PEDF-derived polypeptide composition designed by the invention has good functional advantages, and has obvious effects of resisting inflammation, resisting vascular leakage, protecting alveolar epithelial cells and the like in acute lung injury and chronic non-injury. The derivative polypeptide composition has the advantages of small molecular weight, good treatment effect, easy absorption and poor antigenicity, can effectively avoid anaphylactic reaction and side effect generated when protein drugs are used, is easy to synthesize, obviously reduces the production cost and has higher clinical applicability.

Description

PEDF-derived polypeptide composition and application thereof in preparation of lung injury protection drugs

Technical Field

The invention belongs to the technical field of biological medicines, and particularly relates to a PEDF-derived polypeptide composition and application thereof in preparation of a medicine for protecting lung injury.

Background

Various internal and external pathogenic factors can cause the destruction of the respiratory system and cause acute or chronic lung injury. Acute Lung Injury (ALI) is a common critical clinical condition, the incidence rate of China is 79/10 ten thousand, and the mortality rate is up to 68.5%.

ALI is a disease of alveolar epithelial cell and capillary endothelial cell injury caused by various directly or indirectly traumatic factors, and is manifested by diffuse interstitial pulmonary disease and alveolar edema, and acute hypoxic respiratory insufficiency. ALI occurs in association with neutrophil infiltration and release of cytokines and inflammatory mediators, hyperpermeability of the pulmonary vessels and damage of alveolar epithelial cells are important features of the disease.

A poor prognosis of ALI, or Chronic injury occurring on its basis, leads to the development of Chronic Lung Disease (CLD), idiopathic Pulmonary Fibrosis (IPF) being a common end result of a variety of diseases. The mean survival after IPF diagnosis is only 2.8 years, the mortality rate is higher than that of most tumors, and no effective treatment is available except for lung transplantation.

In conclusion, the prior art has poor effect of preventing and treating lung injury, and further technical means are needed to prevent and treat inflammation, vascular leakage and epithelial cell injury in the lung injury process.

Disclosure of Invention

This section is for the purpose of summarizing some aspects of embodiments of the invention and to briefly introduce some preferred embodiments. In this section, as well as in the abstract and the title of the invention of this application, simplifications or omissions may be made to avoid obscuring the purpose of the section, the abstract and the title, and such simplifications or omissions are not intended to limit the scope of the invention.

The present invention has been made in view of the above-mentioned technical drawbacks.

Accordingly, in one aspect of the present invention, the present invention overcomes the deficiencies of the prior art by providing a composition of PEDF-derived polypeptides.

In order to solve the technical problems, the invention provides the following technical scheme: a PEDF-derived polypeptide composition: consisting of SEQ ID NO:2 and the 34 amino acid sequence peptide shown in SEQ ID NO:3, and the 44 amino acid sequence peptide shown in the figure.

As a preferred embodiment of the PEDF-derived polypeptide composition of the present invention: in the composition, the molar ratio of the 34 amino acid sequence peptide to the 44 amino acid sequence peptide is 1: (0.5-2).

As a preferred embodiment of the PEDF-derived polypeptide composition of the present invention: in the composition, the molar ratio of the 34 amino acid sequence peptide to the 44 amino acid sequence peptide is 1:1.

as a preferred embodiment of the PEDF-derived polypeptide composition of the present invention: the PEDF-derived polypeptide composition can be used for treating acute lung injury and chronic lung injury.

As another aspect of the present invention, the present invention overcomes the deficiencies of the prior art and provides the use of the PEDF-derived polypeptide composition for preparing a medicament for protecting lung injury.

As a preferred embodiment of the application of the PEDF-derived polypeptide composition of the present invention in the preparation of a medicament for protecting lung injury: the PEDF-derived polypeptide composition includes a salt of the PEDF-derived polypeptide composition.

As a preferred embodiment of the application of the PEDF-derived polypeptide composition of the present invention in preparing a medicament for protecting lung injury: the salt, including salts of the PEDF-derived polypeptide composition with organic acids, including acetic acid, lactic acid, maleic acid, citric acid, malic acid, ascorbic acid, succinic acid, benzoic acid, salicylic acid, methanesulfonic acid, toluenesulfonic acid, trifluoroacetic acid, or pamoic acid; the polymeric acid comprises tannic acid, carboxymethyl cellulose; the inorganic acid comprises halogen acid, sulfuric acid and phosphoric acid.

As a preferred embodiment of the application of the PEDF-derived polypeptide composition of the present invention in preparing a medicament for protecting lung injury: the lung injury comprises acute lung injury and chronic lung injury.

As a preferred embodiment of the application of the PEDF-derived polypeptide composition of the present invention in preparing a medicament for protecting lung injury: the medicament comprises loading the PEDF-derived polypeptide composition into a carrier.

As a preferred embodiment of the application of the PEDF-derived polypeptide composition of the present invention in the preparation of a medicament for protecting lung injury: the carrier comprises one or more of solvent, diluent, suspending agent, emulsifier, antioxidant, pharmaceutical preservative, colorant, flavoring agent, medium, oily base, and excipient.

The invention has the beneficial effects that: the PEDF-derived polypeptide composition designed by the invention has good functional advantages, and has obvious effects of resisting inflammation, resisting vascular leakage, protecting alveolar epithelial cells and the like in acute lung injury and chronic non-injury. The derivative polypeptide composition has the advantages of small molecular weight, good treatment effect, easy absorption and poor antigenicity, can effectively avoid anaphylactic reaction and side effect generated when protein drugs are used, is easy to synthesize, obviously reduces the production cost, and has higher clinical applicability.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the description below are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive labor. Wherein:

FIG. 1 is a graph of HE staining of lung tissue in rat acute lung injury induced by lipopolysaccharide according to example 1 of the present invention.

FIG. 2 is a photograph of a Cleaved Caspase-3 (cleared Caspase-3) immunoblot of the acute lung injury cell model of example 2 of the present invention.

FIG. 3 is a histogram showing the statistics of the Cleaved Caspase-3 (cleared Caspase-3) expression levels in the acute lung injury cell model of example 2 of the present invention.

FIG. 4 is a graph of HE staining of lung tissue in rats with chronic lung injury induced by bleomycin in example 3 of the present invention.

FIG. 5 is a graph showing Masson staining of lung tissue in rats with chronic lung injury induced by bleomycin in example 3 of the present invention.

FIG. 6 is a histogram showing the degree of fibrosis of chronic lung injury induced by bleomycin in rat in example 3 of the present invention.

FIG. 7 is an immunoblot of human lung fibroblast-expressed alpha-smooth muscle actin (. Alpha. -SMA) of example 4 of the invention.

FIG. 8 is a histogram showing the expression level of alpha-smooth muscle actin (alpha-SMA) expressed by fibroblasts of example 4 of the present invention.

FIG. 9 is an immunoblot of human endothelial cell expressed alpha-smooth muscle actin (alpha-SMA) of example 5 of the invention.

FIG. 10 is a histogram showing the expression level of alpha-smooth muscle actin (alpha-SMA) expressed by human endothelial cells in example 5 of the present invention.

Detailed Description

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with examples are described in detail below.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, however, the present invention may be practiced otherwise than as specifically described herein, and it will be appreciated by those skilled in the art that the present invention may be practiced without departing from the spirit and scope of the present invention and that the present invention is not limited by the specific embodiments disclosed below.

Furthermore, the references herein to "one embodiment" or "an embodiment" refer to a particular feature, structure, or characteristic that may be included in at least one implementation of the present invention. The appearances of the phrase "in one embodiment" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

All peptide sequences mentioned herein are written according to general convention with the N-terminal amino acid on the left and the C-terminal amino acid on the right. The short line between two amino acid residues indicates a peptide bond.

The compounds of the present invention may be provided in the form of pharmaceutically acceptable salts. Examples of preferred salts are those formed with pharmaceutically acceptable organic acids such as acetic acid, lactic acid, maleic acid, citric acid, malic acid, ascorbic acid, succinic acid, benzoic acid, salicylic acid, methanesulfonic acid, toluenesulfonic acid, trifluoroacetic acid or pamoic acid, as well as polymeric acids such as tannic acid or carboxymethylcellulose, and salts with inorganic acids such as hydrohalic acids (e.g., hydrochloric acid, sulfuric acid or phosphoric acid, etc.). Any method known to those skilled in the art to obtain pharmaceutically acceptable salts may be used.

For convenience in describing the invention, conventional and non-conventional abbreviations for the various amino acid residues are used. These abbreviations are familiar to those skilled in the art, but are listed below for clarity:

asp = D = aspartic acid; ala = a = alanine; arg = R = arginine;

asn = N = asparagine; gly = G = glycine; glu = E = glutamic acid;

gln = Q = glutamine; his = H = histidine; ile = I = isoleucine;

leu = L = leucine; lys = K = lysine; met = M = methionine;

phe = F = phenylalanine; pro = P = proline; ser = S = serine;

thr = T = threonine; trp = W = tryptophan; tyr = Y = tyrosine;

val = V = valine; cys = C = cysteine.

Example 1:

study of effect of PEDF on protection of lipopolysaccharide-induced acute lung injury in rats

Experimental animals: healthy adult Sprague Dawley (SD) rats weighing 230-250g were randomized into 3 groups, normal control, model, and treatment.

Animal models: a rat acute lung injury model is established by tracheal instillation of Lipopolysaccharide (LPS) aqueous solution (2 mg/kg), a normal control group is instilled with equal amount of physiological saline in a tracheal instillation manner, and a treatment group is instilled with LPS and PEDF mixed aqueous solution, wherein the LPS (2 mg/kg) and the PEDF (1 mg/kg).

The experimental results are as follows:

1. determination of the wet-to-dry weight ratio (W/D) of the lung tissue: after the animal model is established for 24 hours, the rat is killed by exsanguination of abdominal aorta, the left lung is taken out by opening the thoracic cavity, the left lung is cleaned by normal saline, and the left lung is weighed after being sucked dry by filter paper, so that the wet weight (W) of the lung tissue is obtained. The lung tissue was then placed in a 60 ℃ oven for 48h and weighed again to obtain the dry weight of lung tissue (D). The W/D value was calculated to reflect the degree of edema of the lung tissue. The results are shown in Table 1.

TABLE 1

Group of	W/D value
		Normal control group	3.6±0.43
Model set	6.7±0.72*
		Treatment group	4.8±0.55* ^#

P compared to normal control group<0.05; in comparison to the set of models, ^# P<0.05。P<0.05 indicated significant differences.

As shown in Table 1, compared with the normal control group, the W/D value of the model group is obviously increased, which indicates that the pulmonary tissue edema is serious, and compared with the W/D value of the PEDF treatment group, the W/D value of the model group is reduced, and the pulmonary tissue edema is not deep, which proves that the PEDF can effectively reduce the pulmonary tissue edema caused by acute lung injury.

2. Protein Permeability Index (PPI) assay: after 24h of animal model establishment, fresh blood was drawn through the abdominal main vein at 0.5ml, followed by abdominal aortic bleeding to sacrifice the rats, cervical skin was incised, trachea was exposed, and the lung bronchi were lavaged with sterile physiological saline (5 ml each, repeated 3 times) to obtain bronchoalveolar lavage fluid. The serum protein concentration and the bronchoalveolar lavage fluid protein concentration were measured using a total protein quantitative determination kit (commercially available), and the PPI value was calculated: (bronchoalveolar lavage fluid protein concentration/serum protein concentration) × 100 to reflect pulmonary vascular permeability. The results are shown in Table 2.

TABLE 2

Group of	PPI value
		Normal control group	0.13±0.02
Model set	0.85±0.15*
		Treatment group	0.46±0.07*#

P <0.05 compared to normal control group; compared to the model group, # P <0.05.P <0.05 indicates significant differences.

As shown in Table 2, compared with the normal control group, the PPI value of the model group is obviously increased, which indicates that the pulmonary vascular permeability is obviously increased, and the PPI value of the PEDF treatment group is reduced and the pulmonary vascular permeability is slightly increased compared with the model group, thus proving that the PEDF can effectively reduce the pulmonary vascular permeability of acute lung injury and protect the endothelial barrier.

3. Pathological observation of lung tissues: and (3) taking the right lung middle lobe of the rat, placing the right lung middle lobe of the rat in a 4% paraformaldehyde solution for fixation for 24 hours, then carrying out conventional paraffin-embedded section and HE staining, and observing the pathological condition of lung tissues of the rat in each group. The results are shown in FIG. 1.

As shown in FIG. 1, the normal control group had clear and intact lung tissue structure, smooth alveolar walls and no effusion or exudate in alveolar spaces; the lung tissue structure of the model group is disordered, the pulmonary interstitium is obviously widened, the basement membrane is broken and damaged, and a large amount of exudates and inflammatory cell infiltration can be seen in the alveolar cavity; compared with the model group, the treatment group has the advantages of obvious reduction of various pathological features, slight disorder of lung tissue structure, slight broadening of lung interstitium, complete pulmonary alveolus and no obvious effusion or exudate. PEDF treatment was shown to be effective in reducing lipopolysaccharide-induced acute lung injury in rats. Column 1A represents the normal control group, column 1B represents the model group, and column 1C represents the treatment group. Bar =50um.

Example 2:

research on TNF-alpha stimulated rat alveolar type II epithelial cell RLE-6TN protection effect of PEDF and polypeptide derived from PEDF

Test cells: rat alveolar type II epithelial cells (RLE-6 TN) were purchased from Gechenochi Biotech, inc. in Shanghai. The group was randomly divided into 6 groups, a normal control group, a model group, a PEDF group (amino acid sequence shown in SEQ ID NO: 1), a 34 peptide group (amino acid sequence shown in SEQ ID NO: 2), a 44 peptide group (amino acid sequence shown in SEQ ID NO: 3), a 34 peptide and 44 peptide mixed peptide group (mixed in a molar ratio of 1.

Cell model: an acute lung injury cell model is constructed by stimulating RLE-6TN cells (10 ng/mL) by using tumor necrosis factor (TNF-alpha), and is cultured routinely in a normal control group, a PEDF treatment group applies PEDF intervention (20 nmol/L) at the same time of administering the TNF-alpha, a 34 peptide treatment group applies 34 peptide intervention (20 nmol/L) at the same time of administering the TNF-alpha, a 44 peptide treatment group applies 44 peptide intervention (20 nmol/L) at the same time of administering the TNF-alpha, and a 34 peptide and 44 peptide mixed peptide treatment group applies 34 peptide and 44 peptide mixed peptide intervention (20 nmol/L) at the same time of administering the TNF-alpha.

The experimental results are as follows:

determination of the degree of apoptosis: after 36h after the cell model was established, the cells were harvested, 500. Mu.l of lysate (commercially available) was added to each 10cm dish, lysed 30min on ice or at 4 ℃ and centrifuged at 14000rpm for 20min at 4 ℃ and the supernatant was taken. Leave 15-20 μ l of sample for protein quantification and store the rest in a refrigerator at-20 ℃ for future use. Samples were incubated with protein treatment solution (commercially available) at 4:1, uniformly mixing, boiling for 10min to fully denature protein; naturally cooling, and storing at-20 deg.C for use.

The expression level of Cleaved Caspase-3 (cleaned Caspase-3) representing the degree of apoptosis was detected by Western Blot, and the quantitative protein analysis was performed by ImageJ software, and the statistical analysis was performed using the ratio of the gray level of the target protein to the gray level of the internal reference (. Beta. -tubulin). The results are shown in FIGS. 2 and 3.

As shown in FIGS. 2 and 3, the expression level of clear Caspase-3 in the model group was significantly increased as compared with that in the normal control group; compared with the model group, the PEDF group has obviously reduced clear Caspase-3 expression level; compared with a model group, the expression level of the cleared Caspase-3 in the 34 peptide group is not obviously changed; the expression level of the 44 peptide group is reduced compared with that of the model group, but is higher than that of the PEDF group; peptide 34 and peptide 44 the clear Caspase-3 expression level was lower than that of peptide 44 and slightly higher than that of PEDF. Proved that PEDF, 44 peptide and 34 peptide and 44 peptide mixed peptide can effectively protect alveolar epithelial cells and reduce apoptosis in acute lung injury. Column 2A represents the normal control group, column 2B represents the model group, column 2C represents the PEDF group, column 2D represents the 34 peptide group, column 2E represents the 44 peptide group, column 2F represents the 34 peptide and 44 peptide groups. P <0.05 compared to normal control group; compared to the model group, # P <0.05.P <0.05 indicates significant differences.

Example 3:

study of the protective effect of PEDF on bleomycin-induced chronic lung injury in rats

The experimental animals were randomly divided into 4 groups, normal control group, model group, sham-treated group, and treated group, as in example 1.

Animal model: a rat chronic lung injury model is established by tracheal instillation of bleomycin (5 mg/kg), a normal control group is given with equal amount of normal saline, a treatment group is given with equal amount of normal saline by tracheal instillation of PEDF (1 mg/kg) aqueous solution for three times every three days after the model is established, and a sham treatment group is given with equal amount of normal saline every three days.

The experimental results are as follows:

pathological observation of lung tissues: in the same manner as in example 1, the right middle lung lobe of rat was subjected to conventional paraffin-embedded section, HE staining, and Masson staining. HE staining is shown in FIG. 4 and Masson staining is shown in FIG. 5.

The degree of pulmonary fibrosis was classified as 4: grade 0 with no obvious change; grade 1 mild changes, with a range of lesions less than 20% of the total lung; grade 2 moderate changes, with lesion range of 20% -50% of the total lung; grade 3 severe changes, with a range of lesions over 50% of the total lung. The evaluation results are shown in FIG. 6.

The results are shown in fig. 4, 5, and 6: the normal control group has complete and clear lung tissue structure, normal pulmonary interstitium, no obvious effusion or exudate in the alveolar cavity, no inflammatory cell infiltration or fibroblast proliferation, and a small amount of collagen fiber deposition in large bronchus and large blood vessel; the pulmonary alveolar structures of the model group and the pseudo-treatment group are seriously damaged, the pulmonary spacing is obviously thickened, the pulmonary alveolar cavity is atrophied and collapsed, a large amount of inflammatory cell infiltration and fibroblast proliferation can be seen, a large amount of collagen fibers are deposited, and the pulmonary fibrosis degree is serious; the lung tissue structure of the PEDF group is complete and clear, the lung interstitium is slightly thickened, a small amount of inflammatory cell infiltration and a small amount of fibroblast hyperplasia can be seen, the collagen fiber deposition is less, and the degree of pulmonary fibrosis is obviously lighter than that of the model group and the pseudo-treatment group. PEDF was shown to be effective in reducing the degree of fibrosis associated with chronic lung injury. Column 4A/5A represents the normal control group, column 4B/5B represents the model group, column 4C/5C represents the sham-treated group, and column 4D/5D represents the treated group. Bar =50um. P <0.05 compared to normal control group; compared to the model group, # P <0.05.P <0.05 indicates significant differences.

Example 4:

research on activation of human lung fibroblast MRC-5 stimulated by TGF-beta 1 through PEDF and polypeptide derived from PEDF

Test cells: human lung fibroblasts (MRC-5) were purchased from Gechenochi Biotech, inc. in Shanghai, and randomly divided into 6 groups, normal control group, model group, PEDF group, 34 peptide group, 44 peptide group, 34 peptide and 44 peptide mixed peptide group.

The experimental results are as follows:

alpha-smooth muscle actin (alpha-SMA) expression amount determination: after 24h of cell model establishment, cell protein was extracted as in example 2, the expression level of α -SMA was detected by Western Blot, quantitative protein analysis was performed by ImageJ software, and statistical analysis was performed using the ratio of the gray level of the target protein to the gray level of the internal reference (. Beta. -tubulin). The results are shown in FIGS. 7 and 8.

As shown in fig. 7 and 8: compared with a normal control group, the alpha-SMA expression level of the model group is obviously increased; compared with a model group, the PEDF group has obviously reduced alpha-SMA expression level; the 34 peptide group slightly reduces the alpha-SMA expression compared with the model group, but has no statistical significance; the expression level of the 44 peptide group compared with that of the model group alpha-SMA has no obvious change; the 34 peptide and 44 peptide groups slightly reduced the expression level of alpha-SMA compared with the model group, but higher than that of PEDF group. The PEDF is proved to be capable of effectively inhibiting the activation of human lung fibroblasts and relieving the fibrosis degree in acute lung injury, but the effect of the derived polypeptide is not good enough.

Column 7A represents the normal control group, column 7B represents the model group, column 7C represents the PEDF group, column 7D represents the 34 peptide group, column 7E represents the 44 peptide group, and column 7F represents the 34 peptide and 44 peptide mixed peptide group. P <0.05 compared to normal control group; compared to model group, # P <0.05.P <0.05 indicates significant differences.

Example 5:

research on PEDF and derived polypeptide thereof for inhibiting TGF-beta 1-stimulated endothelial intercellular substance transformation

Experimental cells: human Coronary Microvascular Endothelial Cells (HCMECs) were purchased from Sciencell, and randomly divided into 6 groups: normal control group, model group, PEDF group, 34 peptide group, 44 peptide group, 34 peptide and 44 peptide mixed peptide group.

Cell model: an endothelial mesenchymal transition model was constructed by stimulating cells (10 ng/ml) with transforming growth factor (TGF-. Beta.1), and cultured routinely in a normal control group, the PEDF group was administered with PEDF intervention (20 nmol/L) simultaneously with TGF-. Beta.1, the 34 peptide group was administered with 34 peptide intervention (20 nmol/L) simultaneously with TGF-. Beta.1, the 44 peptide group was administered with 44 peptide intervention (20 nmol/L) simultaneously with TGF-. Beta.1, and the 34 peptide and 44 peptide mixed peptide group was administered with 34 peptide and 44 peptide mixed peptide intervention (20 nmol/L) simultaneously with TGF-. Beta.1.

The experimental results are as follows:

alpha-smooth muscle actin (alpha-SMA) assay: after 48h of cell model establishment, cell protein was extracted as in example 2, the expression level of α -SMA was detected by Western Blot, quantitative protein analysis was performed by ImageJ software, and statistical analysis was performed using the ratio of the gray level of the target protein to the gray level of the internal reference (. Beta. -tubulin). The results are shown in FIGS. 9 and 10.

As shown in fig. 9 and 10, compared with the normal control group, the expression level of the model group α -SMA is significantly increased; compared with a model group, the PEDF group has obviously reduced alpha-SMA expression level; 34, compared with the model group, the alpha-SMA expression level is reduced, but is not as remarkable as that of the PEDF group; the expression level of the 44 peptide group compared with that of the model group alpha-SMA has no obvious change; the alpha-SMA expression of the 34 peptide and 44 peptide groups is lower than that of the 44 peptide group and slightly higher than that of the PEDF group. Proved that the PEDF, the 44 peptide and the 34 peptide and 44 peptide mixed peptide can effectively inhibit the mesenchymal transition of endothelial cells and reduce the source of fibroblasts in the chronic lung injury.

Column 9A represents the normal control group, column 9B represents the model group, column 9C represents the PEDF group, column 9D represents the 34 peptide group, column 9E represents the 44 peptide group, column 9F represents the 34 peptide and 44 peptide groups. P <0.05 compared to normal control group; compared to the model group, # P <0.05.P <0.05 indicates significant differences.

The PEDF holoprotein has larger molecules, higher synthesis cost and poorer clinical applicability, and the derivative polypeptide composition has small molecular weight, good treatment effect, easy absorption and poor antigenicity, can effectively avoid the anaphylactic reaction and side effect generated when protein drugs are used, is easy to synthesize, obviously reduces the production cost and has higher clinical applicability.

The invention relates to an amino acid sequence:

PEDF amino acid sequence (SEQ ID NO: 1):

MQALVLLLCIGALLGHSSCQNPASPPEEGSPDPDSTGALVEEEDPFFKVPVNKLAAAVSNFGYDLYRVRSSMSPTTNVLLSPLSVATALSALSLGADERTESIIHRALYYDLISSPDIHGTYKELLDTVTAPQKNLKSASRIVFEKKLRIKSSFVAPLEKSYGTRPRVLTGNPRLDLQEINNWVQAQMKGKLARSTKEIPDEISILLLGVAHFKGQWVTKFDSRKTSLEDFYLDEERTVRVPMMSDPKAVLRYGLDSDLSCKIAQLPLTGSMSIIFFLPLKVTQNLTLIEESLTSEFIHDIDRELKTVQAVLTVPKLKLSYEGEVTKSLQEMKLQSLFDSPDFSKITGKPIKLTQVEHRAGFEWNEDGAGTTPSPGLQPAHLTFPLDYHLNQPFIFVLRDTDTGALLFIGKILDPRGP

34 peptide amino acid sequence (44-77 aa) (SEQ ID NO: 2):

DPFFKVPVNKLAAAVSNFGYDLYRVRSSMSPTTN

44 peptide amino acid sequence (78-121 aa) (SEQ ID NO: 3):

VLLSPLSVATALSALSLGAEQRTESIIHRALYYDLISSPDIHGT

it should be noted that the above-mentioned embodiments are only for illustrating the technical solutions of the present invention and not for limiting, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, which should be covered by the claims of the present invention.

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Claims

1. The application of the PEDF-derived polypeptide composition in preparing the medicine for protecting acute lung injury is characterized in that:

the PEDF-derived polypeptide composition consists of SEQ ID NO:2 and the 34 amino acid sequence peptide shown in SEQ ID NO:3, and a 44 amino acid sequence peptide shown in the specification;

the molar ratio of the 34 amino acid sequence peptide to the 44 amino acid sequence peptide is 1:0.5 to 2.