阅读说明：本技术 一种多肽片段b及其应用 (Polypeptide fragment B and application thereof ) 是由 张彩华 常英 于 2021-02-02 设计创作，主要内容包括：本发明属于生物医药技术领域,具体涉及一种多肽片段B及其应用,所述多肽片段B具有SEQ ID No.1所示的氨基酸序列,其中,第10位氨基酸Xaa为Arg、Phe、Glu、Thr或不存在,第16位氨基酸Xaa为Asn、Val、Leu、Gly或不存在,第25位氨基酸Xaa为Ser、Glu、Met、Arg或不存在。MP-B显著改善了IBD小鼠模型的结肠病理性形态,降低了结肠组织病理学评分和结肠干扰素-γ表达含量,具有干预小鼠炎症性肠病发生的能力。(The invention belongs to the technical field of biological medicines, and particularly relates to a polypeptide fragment B and application thereof, wherein the polypeptide fragment B has an amino acid sequence shown in SEQ ID No.1, wherein amino acid Xaa at the 10 th position is Arg, Phe, Glu and Thr or does not exist, amino acid Xaa at the 16 th position is Asn, Val, Leu and Gly or does not exist, and amino acid Xaa at the 25 th position is Ser, Glu, Met and Arg or does not exist. MP-B significantly improves colon pathomorphology of IBD mouse model, reduces colon histopathology score and colon interferon-gamma expression content, and has the ability to interfere with the development of inflammatory bowel disease in mice.)

1. A polypeptide fragment B, characterized by having an amino acid sequence shown in SEQ ID No. 1.

2. The polypeptide fragment B of claim 1, wherein the amino acid Xaa at position 10 of the amino acid sequence shown in SEQ ID No.1 is Arg, Phe, Glu, Thr or absent, the amino acid Xaa at position 16 is Asn, Val, Leu, Gly or absent, and the amino acid Xaa at position 25 is Ser, Glu, Met, Arg or absent.

3. Use of the polypeptide fragment B of claim 1 in the preparation of a medicament against inflammatory bowel disease.

4. Use of the polypeptide fragment B of claim 1 in the preparation of a food or food additive for anti-inflammatory bowel disease.

5. The use of the polypeptide fragment B of claim 1 in the preparation of a health product for treating inflammatory bowel disease.

6. Use according to claim 3, for the preparation of a medicament for ameliorating the pathological colon shortening of inflammatory bowel disease.

7. Use according to claim 3, for the preparation of a medicament for reducing the colon histopathological score of inflammatory bowel disease.

8. A pharmaceutical formulation comprising the polypeptide fragment B of claim 1 and a pharmaceutically acceptable carrier, excipient or diluent.

9. The pharmaceutical preparation according to claim 8, wherein the pharmaceutical preparation is in the form of injection, capsule, tablet, granule, suspension, enema, emulsion or powder.

Technical Field

The invention belongs to the technical field of biological medicines, and particularly relates to a polypeptide fragment B and application thereof.

Background

Inflammatory Bowel Disease (IBD) is an idiopathic chronic inflammatory bowel disease, the lesions of which are mainly located in the colorectal segment and involve mucous membrane and mucous membrane muscularis, and serious complications in liver, gallbladder, muscle skin and blood coagulation, and 20-30% of patients who relapse may be transformed into colorectal cancer, and the IBD is a very serious inflammatory bowel disease and can be divided into Ulcerative Colitis (UC) and Crohn's Disease (CD). IBD is considered to be an intestinal inflammatory reaction caused by abnormal intestinal mucosal innate immunity and acquired immunity under the interaction of multiple factors such as environment, heredity, infection and immunity, and the inflammatory reaction in the intestinal mucosal innate layer is considered to be a cornerstone of IBD pathogenesis. In recent decades, the incidence rate of IBD has been on the rise year by year, and traditional IBD treatment drugs, such as salicylic acids, steroid hormones, immunosuppressants and the like, mainly reduce inflammation and regulate immune disorders to effectively control the onset of disease, but these traditional methods cannot completely cure IBD, are often accompanied with serious adverse reactions, and cause serious damage to the quality of life of patients, so that a new IBD treatment method is urgently needed.

In recent years, probiotics are becoming a new approach for the treatment of IBD, and research shows that such preparations can improve dysbacteriosis of IBD patients to different degrees in intestinal tract. Lactobacillus L.plantarum is a common probiotic, and researches show that lactobacillus L.plantarum can inhibit the damage of pathogenic bacteria in intestinal tracts through adhesion and colonization, regulate the intestinal permeability of immunodeficient mice, and further intervene the development of colitis, and microfilmin (MIMP) is an active polypeptide fragment which is separated from L.plantarum CGMCC 1258 strain and can competitively adhere to intestinal epithelial cells with invasive pathogenic escherichia coli, and the sequence is shown in SEQ ID No. 2: THTVGSYFSVQNGYVGAFSQALGNSEYAMNSPLGSLDGRTTMYNLLGVKYLFAREDQLKKQ, the fragment can significantly improve the inflammatory state of intestinal tract and prevent IBD mice intestinal flora imbalance. However, MIMP is a biomacromolecule consisting of 61 amino acids, and the relatively large molecular weight is easy to generate immunogenicity and not easy to form a medicament, so that the clinical application of MIMP is limited; in addition, the higher molecular weight is not favorable for the industrial production of the drug. From the aspects of medicinal value and economic benefit, the MIMP is further structurally modified and reformed to improve the pharmacological activity or/and the patent drug property of the MIMP fragment, thereby being beneficial to the clinical application and the economic benefit of the active fragment.

Disclosure of Invention

In order to overcome the defects of easy immunogenicity generation and difficult drug preparation of MIMP (MIMP) with an improvement effect on inflammatory bowel diseases in the prior art, the invention aims to provide a polypeptide fragment B, a pharmaceutical preparation and application thereof.

The invention is realized by the following technical scheme:

the invention provides a polypeptide fragment B, which has an amino acid sequence shown in SEQ ID No. 1.

Preferably, the amino acid Xaa at the 10 th position of the amino acid sequence shown in SEQ ID No.1 is Arg, Phe, Glu, Thr or is absent, the amino acid Xaa at the 16 th position is Asn, Val, Leu, Gly or is absent, and the amino acid Xaa at the 25 th position is Ser, Glu, Met, Arg or is absent.

The invention also provides application of the polypeptide fragment B in preparing anti-inflammatory bowel disease medicines.

The invention also provides application of the polypeptide fragment B in preparing anti-inflammatory bowel disease foods or food additives.

The invention also provides application of the polypeptide fragment B in preparing anti-inflammatory bowel disease health-care products.

Preferably, the polypeptide fragment B is used for preparing a medicament for improving the pathological colon shortening of the inflammatory bowel disease.

Preferably, the use of said polypeptide fragment B for the preparation of a medicament for reducing the colon histopathological score of inflammatory bowel disease.

The invention also provides a pharmaceutical formulation comprising the polypeptide fragment B of claim 1 and a pharmaceutically acceptable carrier, excipient or diluent.

Preferably, the pharmaceutical preparation is in the form of injection, capsule, tablet, granule, suspension, enema, emulsion or powder.

Compared with the prior art, the invention has the beneficial effects that:

the invention establishes an acute Inflammatory Bowel Disease (IBD) mouse model by a Dextran Sodium Sulfate (DSS) chemical induction method, and explores whether a polypeptide fragment B (MP-B for short) has an improvement effect on the IBD mouse model by a colon morphology and histopathology analysis method. The research result shows that under the same dosage with MIMP, the intervention of the polypeptide fragment B obviously improves the colon pathophysiology morphology of an IBD mouse model, reduces the colon histopathology score of the IBD mouse model, and has the capability of improving and intervening the occurrence of the inflammatory bowel disease of the mouse. And compared with MIMP, the MP-B fragment has smaller molecular weight, is also beneficial to the pharmacy and application of the MP-B fragment, and discloses the application potential of the polypeptide fragment B in the preparation of active products for preventing, intervening and treating inflammatory bowel diseases.

The abbreviations used in the present invention have the following specific meanings:

thr is threonine; his is histidine; val is valine; gly is glycin; ser is serine; phe is phenylalanine; asn is asparagine; tyr is tyrosine; ala is alanine; leu is leucine; glu is glutamic acid; met is methionine; pro is proline; asp is aspartic acid; arg is arginine; lys is lysine; gln is glutamine.

Drawings

FIG. 1 is a graph showing the body weight change trend of a model group mouse and a blank control group mouse,^#P<0.05，^##P<0.01，^###P<0.001, comparing with a blank control group, and carrying out significance test on two independent samples by t test;

FIG. 2 is a graph showing the comparison of colon lengths of mice in a placebo group, a model group, a MIMP positive control group and an MP-B experimental group,^*P<0.05,^**P<0.01，^***P<0.001, compared to model group;^##P<0.01, single factor analysis of variance for significance test compared to blank control;

FIG. 3 is a histopathological micrograph of colon of mice in blank control group, model group, MIMP positive control group and MP-B experimental group (HE staining 20 Xmicroscopy; A. blank control group; B. model group; C. MIMP positive control group; D.MP-B experimental group);

histopathological score comparison graph (A)^*P<0.05，^**P<0.01，^***P<0.001, compared to model group;^###P<0.001, one-way variance compared to blank controlAnalysis for significance testing).

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The reagents, materials and equipment used in the examples are shown in table 1:

TABLE 1

Name (R)	Manufacturer(s)
		Male C57BL6 mouse, clean grade	Shanghai Si Laike company (Shanghai, China)
Dextran Sulfate Sodium (DSS)	MP Biomedicals(CA,United States)
		Phosphoric acid buffer solution (PBS)	Shanghai Bo photo-biological technology Co., Ltd (Shanghai, China)
MIMP	Suzhou Qiangyao biological company (Suzhou, China)
		4% Paraformaldehyde	Shanghai Bo photo-biological technology Co., Ltd (Shanghai, China)

Example 1: experiment of intervention of MP-B on effect of DSS (direct sequence-derived leukemia) on induction of Inflammatory Bowel Disease (IBD) in mice

The polypeptide fragment B (MP-B) used in this example has a sequence in which Xaa at the 10 th amino acid position of the amino acid sequence shown in SEQ ID No.1 is Glu, Xaa at the 16 th amino acid position is Gly, and Xaa at the 25 th amino acid position is Met, that is, SPLGSLDGRETMYNLGGVKYLFARMDQLKKQ.

1. Experimental methods

1.1 establishment of mouse model of acute inflammatory bowel disease

When given to mice with a certain concentration of DSS solution, acute inflammatory bowel disease models characterized by diarrhea, fecal blood, ulcers, and granulocytic infiltration were induced. Experimental grouping the randomized grouping was done hierarchically according to the body weight of the mice, following the randomization principle. 40 healthy male C57BL6 mice were divided into four groups of 10 mice each:

blank control group: the stomach is irrigated with water every day, and the volume of the irrigated stomach is 0.4mL/20 g;

model group: performing intragastric administration with 2.5 wt% DSS aqueous solution, and continuously drinking for 7 days, wherein the DSS aqueous solution is prepared fresh and is replaced for 1 time every 1 day;

MIMP positive control group: the mice are firstly given a pre-administration process of one week, namely, the mice are gazed with a MIMP solution with the mass fraction of 50 mu g/kg in the first 7 days, and are gazed with a 2.5 wt% DSS aqueous solution (the gazed volume is 0.4mL/20g) every day and are gazed with a MIMP solution with the mass fraction of 50 mu g/kg (the gazed volume is 0.4mL/20g) starting from the day 8;

MP-B experimental group: the mice are firstly administrated with a one-week pre-administration process, namely, the mice are gavaged with a MP-B solution with the mass fraction of 50 mug/kg on the first 7 days, and are gavaged with a 2.5 wt% DSS aqueous solution (the gavage volume is 0.4mL/20g) every day and are gavaged with a MP-B solution with the mass fraction of 50 mug/kg (the gavage volume is 0.4mL/20g) starting on the 8 th day;

the change in body weight of each group of mice was recorded daily to determine whether the mouse model of acute inflammatory bowel disease was successfully established.

1.2 sample Collection

Mice were sacrificed by dislocation of cervical vertebrae, placed on an operating table, the abdominal cavity was exposed, and intestinal conditions were observed, with or without hyperemia, ulceration, and adhesion. Simultaneously, the colon of the mouse is completely taken out from the anus end to the ileocecal end, and after the length of the colon is measured, the intestinal tract is cut open along the longitudinal axis, and the excrement of the intestinal tract is washed and stored in 4 percent of methanol.

1.3 histopathological evaluation

Histopathological sectioning of the colon samples stored in 4% paraformaldehyde in step 1.2, hematoxylin-eosin staining, dehydration, sealing of sections and examination under an optical microscope, histopathological scoring by two blind examiners:

evaluation criteria: 0 point, no obvious inflammation; 1 minute, moderate inflammation infiltration of the basal layer; 2 points, moderate hyperplasia or severe inflammatory infiltration of mucosa; 3 points, mucosa is heavily hyperplastic, goblet cells are absent; in score 4, crypts were absent or ulcerated.

1.4 statistical analysis

Experimental data in the above experimental methodsIt is shown that the statistical tests were performed using GraphPad Prism (ver.8.0, GraphPad Software inc., San Diego, CA, USA), SPSS Program (ver.25.0, SPSS inc., Chicago, IL, USA), and the significance tests were performed using one-way anova or two independent sample t-tests when normality and homogeneity of variance were met. Let alpha equal to 0.05, P<A difference of 0.05 was statistically significant.

2. Analysis of Experimental results

2.1 intervention of MP-B significantly ameliorates pathological colon shortening in mice with inflammatory bowel disease

Fig. 1 is a graph showing the weight change trend of the model group mice and the blank control group mice, and it can be seen that the body weight of the model group mice significantly decreased one week after the induction of DSS administration (compared to the blank control group,^###P<0.001 with significant difference), indicating that the mouse model of acute inflammatory bowel disease is successfully established.

FIG. 2 is a graph showing the comparison of colon lengths of mice in the placebo group, the model group, the MIMP positive control group and the MP-B experimental group, and it can be seen that the colon length (5.3. + -. 0.6) of the mice in the model group is significantly shortened compared with that in the placebo group (colon length 9.2. + -. 0.8) ((^###P<0.001), whereas the colon shortening of the MP-B experimental group mice (colon length 8.0 +/-0.5) is significantly different relative to the colon shortening of the model group mice (colon length 5.3 +/-0.6) (compared with the model group,^***P<0.001, there is a significant difference), indicating that the intervention of MP-B can significantly reverse this shortening, comparable to the effect of MIMP positive control group (colon length 7.6 ± 0.5), improving the pathological colon morphology in mice with inflammatory bowel disease.

2.2 intervention of MP-B significantly reduced Colon histopathology scores in mice with inflammatory bowel disease

FIG. 3 is a histopathological micrograph of colon of mice in blank control group, model group, MIMP positive control group and MP-B experimental group (HE staining 20 Xmicroscopy; A. blank control group; B. model group; C. MIMP positive control group; D.MP-B experimental group); histopathological score comparison graph (A)^*P<0.05，^**P<0.01，^***P<0.001, compared to model group;^###P<0.001, significance test by one-way analysis of variance compared to blank control).

Pathology scoring: blank control group A0.0 + -0.0; B. model group 7.6 +/-0.6; MIMP positive control group 3.1 ± 0.2; MP-B panel 1.4. + -. 0.6.

It can be seen that both MIMP and MP-B intervention in colon histopathology scores significantly reduced colon histology scores in mice with inflammatory bowel disease (S) ((S))^***P<0.001 with significant difference). The pathological condition is improved to a corresponding degree, the epithelial structure of a mucous membrane layer is relatively complete, the morphological structure of epithelial cells is normal, and no obvious inflammation occurs, which shows that the intervention of MP-B can improve the large-area ulcer of the mucous membrane layer of colon tissues caused by DSS induction, reduce the infiltration of lymphocytes and neutrophils, and further intervene the occurrence of intestinal inflammation.

Example 2

The reagents, materials and equipment used in this example, as well as the experimental methods, were the same as in example 1, except that: the polypeptide fragment B (MP-B) used in this example has a sequence in which Xaa at the 10 th amino acid position of the amino acid sequence shown in SEQ ID No.1 is Arg, Xaa at the 16 th amino acid position is Asn, and Xaa at the 25 th amino acid position is Glu, that is, SPLGSLDGRRTMYNLNGVKYLFAREDQLKKQ.

Example 3

The reagents, materials and equipment used in this example, as well as the experimental methods, were the same as in example 1, except that: the sequence of the polypeptide fragment B (MP-B) used in this example is a sequence in which Xaa at the 10 th amino acid position of the amino acid sequence shown in SEQ ID No.1 is Thr, Xaa at the 16 th amino acid position is Val, and Xaa at the 25 th amino acid position is Ser, that is, SPLGSLDGRTTMYNLVGVKYLFARSDQLKKQ.

Example 4

The reagents, materials and equipment used in this example, as well as the experimental methods, were the same as in example 1, except that: the sequence of the polypeptide fragment B (MP-B) used in this example is SPLGSLDGRTMYNLGVKYLFARDQLKKQ, which is the sequence when the amino acid Xaa at position 10, the amino acid Xaa at position 16 and the amino acid Xaa at position 25 of the amino acid sequence shown in SEQ ID No.1 are not present.

After the experimental method of example 2-example 4 is tested according to the experimental method of example 1, the analysis result is not much different from the result of example 1, which shows that the intervention of the polypeptide fragment B of the present invention can significantly improve the colon pathological morphology of the IBD mouse model, reduce the colon histopathological score of the IBD mouse model, and have the ability of improving and interfering the occurrence of the inflammatory bowel disease of the mouse.

The above-mentioned embodiments are intended to illustrate the objects, technical solutions and advantages of the present invention in further detail, and it should be understood that the above-mentioned embodiments are only exemplary embodiments of the present invention, and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Sequence listing

<110> Shanghai Long Xin biomedical science and technology Limited

<120> polypeptide fragment B and application thereof

<160> 2

<170> SIPOSequenceListing 1.0

<210> 1

<211> 31

<212> PRT

<213> Lactobacillus plantarum (Lactobacillus plantarum)

<400> 1

Ser Pro Leu Gly Ser Leu Asp Gly Arg Xaa Thr Met Tyr Asn Leu Xaa

1 5 10 15

Gly Val Lys Tyr Leu Phe Ala Arg Xaa Asp Gln Leu Lys Lys Gln

20 25 30

<210> 2

<211> 61

<212> PRT

<213> Lactobacillus plantarum (Lactobacillus plantarum)

<400> 2

Thr His Thr Val Gly Ser Tyr Phe Ser Val Gln Asn Gly Tyr Val Gly

1 5 10 15

Ala Phe Ser Gln Ala Leu Gly Asn Ser Glu Tyr Ala Met Asn Ser Pro

20 25 30

Leu Gly Ser Leu Asp Gly Arg Thr Thr Met Tyr Asn Leu Leu Gly Val

35 40 45

Lys Tyr Leu Phe Ala Arg Glu Asp Gln Leu Lys Lys Gln

50 55 60