Application of BMSCS up-regulation miR-20b to inhibition of ROR [gamma] tSTAT3 down-regulation Th17 to realize repair function of sepsis acute lung injury by mitochondrial metastasis

Abstract

The invention discloses application of bone marrow mesenchymal stem cells (BMSCs), miR-20b, ROR [gamma] t / STAT3 and signal pathways of the bone marrow mesenchymal stem cells, the miR-20b and the ROR [gamma] t / STAT3 to preparation of a medicine for treating sepsis acute lung injury. The application proves that the BMSCs play a key role in up-regulation of miR-20b, inhibition of ROR gamma t / STAT3, down-regulation of Th17 activation and promotion of mitochondrial metastasis in immune regulation of the sepsis acute lung injury, the molecular mechanism of the BMSCs is clarified, new treatment thought and molecular targets are provided for treatment of the sepsis acute lung injury, and the BMSCs have important theoretical and clinical application significance.

Description

Technical Field

[0001] The present invention belongs to the field of immunology, and particularly relates to the use of bone marrow mesenchymal stem cells, miR-20b, RORγt / STAT3 and their signaling pathways in the preparation of drugs for treating sepsis-induced acute lung injury. Background Art

[0002] Sepsis, as a severe infectious disease, has a high incidence rate, with more than 18 million severe sepsis cases globally every year. The condition of sepsis is critical and the fatality rate is high, with approximately 14,000 people dying from its complications every day globally. According to foreign epidemiological surveys, the fatality rate of sepsis has exceeded that of myocardial infarction and has become the main cause of death among non-cardiac patients in the intensive care unit. Studies have found that sepsis can trigger an inflammatory response and make the inflammatory response out of control. A continuously high-level inflammatory response will lead to systemic inflammatory response syndrome (SIRS), which in turn triggers multiple organ dysfunction. Among them, sepsis-induced acute lung injury accounts for the vast majority, and the main hazards include pulmonary edema, hypoxemia, respiratory failure, multiple organ failure, and a high mortality rate. The pathogenesis of acute lung injury involves multiple aspects, including monocyte / neutrophil activation and inflammatory response, epithelial cell injury and permeability change, thrombosis and microcirculation disorder, as well as immunosuppression and immune dysregulation. Generally speaking, the pathogenesis of sepsis-induced acute lung injury is complex and diverse, and is the result of the interaction of multiple aspects. These mechanisms jointly promote the inflammatory response, edema, hypoxia, and injury of lung tissue. Therefore, in-depth study of the pathogenesis of acute lung injury can provide new targets and new ideas for finding new diagnostic and treatment methods.

[0003] Inhibiting the maturation and function of Th17 cells during sepsis-induced acute lung injury can alleviate pulmonary inflammatory damage. Studies have shown that the increase in the level of peripheral blood Th17 cells in patients with sepsis-induced acute lung injury is closely related to the severity of their condition and prognosis. It can be used as an effective predictive indicator and has certain clinical application value. In addition, previous literature research found that inhibiting RORγt / STAT3 can effectively down-regulate Th17 expression. A large number of Th17 cell differentiations occur in the early stage of sepsis-induced acute lung injury, leading to severe inflammatory damage, further aggravating lung epithelial cell injury, and triggering mitochondrial dysfunction. Therefore, mediating the differentiation and function of Th17 cells and synchronously transporting healthy mitochondria to the lesion site are of great significance for the treatment of sepsis-induced acute lung injury. Bone marrow mesenchymal stem cells (BMSCs) can significantly reduce the levels of inflammatory factors such as tumor necrosis factor-α (TNF-α) and interleukins (IL-1β, IL-6), thereby alleviating lung injury. In addition, BMSCs can also protect lung tissue from sepsis damage by reducing the lung wet / dry mass ratio, alleviating alveolar wall structure damage and epithelial cell injury. However, it is still unclear whether BMSCs can inhibit Th17 activation by up-regulating miR-20b to down-regulate RORγt / STAT3 and play an immunoregulatory role in sepsis-induced acute lung injury. In addition, it is also unknown whether this mechanism can promote mitochondrial transfer. Summary of the Invention

[0004] In view of the deficiencies and shortcomings of the prior art, based on the fact that when sepsis-induced acute lung injury occurs, the proportion of Th17 cells in the peripheral blood and bronchoalveolar lavage fluid of patients increases significantly, and is positively correlated with the severity of lung injury. In addition, the secretion of pro-inflammatory factors such as IL-17A increases, further exacerbating the inflammatory response. At the same time, memory γδT17 cells derived from the intestine can migrate to the lungs through the "gut-lung axis", aggregate in the lungs, release IL-17A, cause lung tissue inflammation, trigger further damage, induce cascading amplification of the inflammatory response and form an inflammatory storm, thereby causing damage to lung parenchymal cells, which is the pathological basis of sepsis-induced acute lung injury. At this time, the development of the disease no longer depends on the presence of pathogens and continues to deteriorate. Controlling the excessive inflammatory response is the key to treating sepsis-induced acute lung injury. Therefore, by downregulating the activation of Th17, inhibiting RORγt / STAT3 to promote mitochondrial transfer, and alleviating the excessive immunity of sepsis-induced acute lung injury, the mortality of patients with sepsis-induced acute lung injury can be reduced. Therefore, the present invention intends to find problems from clinical practice, and then find its mechanism of action through animal experiments. By using techniques such as molecular biology, immunology, and cell biology, it is confirmed that BMSCs upregulate miR-20b, inhibit RORγt / STAT3, downregulate Th17 activation, and promote mitochondrial transfer, which play a key role in the immunoregulation of sepsis-induced acute lung injury, and clarify its molecular mechanism, providing new treatment considerations and molecular targets for the treatment of sepsis-induced acute lung injury, which has important theoretical and clinical application significance.

[0005] The present invention systematically reveals the molecular mechanism of BMSCs upregulating miR-20b, inhibiting RORγt / STAT3, downregulating Th17 activation and promoting mitochondrial transfer in sepsis-induced lung injury. Therefore, BMSCs and its miR-20b-RORγt / STAT3 signaling pathway are expected to become therapeutic targets for patients with sepsis-induced acute lung injury.

[0006] Specifically, ELISA is used to detect the expression of TGF-β, IL-17, IL-6, IL-23, IL-21, IFN-γ, IL-2, IL-4 in the sera of patients with sepsis-induced acute lung injury and healthy controls, as well as the changes in Th17 cells in the bronchoalveolar lavage fluid of patients with sepsis-induced acute lung injury and healthy controls: IL-17A+, CD4+, CD196(CCR6)+, RORγt; ELISA is used to detect the expression of TGF-β, IL-17, IL-6, IL-23, IL-21, IFN-γ, IL-2, IL-4 and Socs3 in the peripheral blood of patients with sepsis-induced acute lung injury and healthy controls, and the changes in Th17 cells in the bronchoalveolar lavage fluid of healthy controls: IL-17A+, CD4+, CD196(CCR6)+, RORγt.

[0007] In this invention, animal experiments were further conducted to confirm the in vivo phenotypes and mechanisms of BMSCs in upregulating miR-20b, inhibiting RORγt / STAT3, downregulating Th17 activation, and promoting mitochondrial transfer in sepsis-induced lung injury. Specifically, it includes: Establishment of an acute lung injury model induced by sepsis: C57BL / 6J mice were selected, and an acute lung injury (ALI) model was established by cecal ligation. The pathological conditions of the lung tissues of mice in each group were detected by HE staining, and the survival rate of the mice was calculated and the survival curve was plotted to compare the differences in survival rates between groups. The expression levels and proportions of immune cells in the bronchoalveolar lavage fluid of mice in each group were detected by flow cytometry. In addition, the expression levels of related factors in the bronchoalveolar lavage fluid of mice in each group were detected by ELISA.

[0008] This invention provides the use of bone marrow mesenchymal stem cells in the preparation of drugs for treating sepsis-induced acute lung injury.

[0009] This invention provides the use of miR-20b in the preparation of drugs for treating sepsis-induced acute lung injury.

[0010] This invention provides the use of RORγt / STAT3 in the preparation of drugs for treating sepsis-induced acute lung injury.

[0011] This invention provides the use of the miR-20b-RORγt / STAT3 signaling pathway in the preparation of drugs for treating sepsis-induced acute lung injury.

[0012] Compared with the prior art, this invention has the following advantages and effects: The invention discovers problems clinically and then finds out its mechanism of action through animal experiments. By using techniques such as molecular biology, immunology, and cell biology, it is confirmed that BMSCs play a key role in immunomodulation of sepsis-induced acute lung injury by upregulating miR-20b, inhibiting RORγt / STAT3, downregulating Th17 activation, and promoting mitochondrial transfer, and clarifies its molecular mechanism, providing new treatment considerations and molecular targets for the treatment of sepsis-induced acute lung injury, which has important theoretical and clinical application significance. Brief Description of the Drawings

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0014] Figure 1 It is the relevance of Th17 cells (IL-17A+, CD4+, CD196(CCR6)+, RORγt) in the bronchoalveolar lavage fluid of patients in clinical sample analysis and the pro-inflammatory and anti-inflammatory factors promoting and inhibiting Th17 differentiation detected by Elisa to sepsis-induced acute lung injury diseases: Figure 1A represents the expression levels of IL-17A+, CD4+, CD196(CCR6)+, and RORγt in bronchoalveolar lavage fluid of healthy subjects and patients with acute lung injury induced by sepsis. Figure 1 B represents the expression levels of Th17 pro-inflammatory and anti-inflammatory related factors in peripheral blood serum of patients with sepsis-induced acute lung injury and control patients.

[0015] Figure 2 shows the molecular mechanism by which BMSCs upregulate miR-20b, inhibit RORγt / STAT3, downregulate Th17 activation, and promote mitochondrial transfer in sepsis-induced lung injury: Figure 2A The binding sites of miRNA-20b and RORγt / STAT3 target genes were predicted by miranda software and further verified by dual-luciferase reporter assay (miRNA-20b can target and bind to inhibit RORγt / STAT3); Figure 2B For flow cytometry detection of Th17 cell markers: IL-17A+CD4+CD196(CCR6)+, RORγt; Figure 2C For ELISA detection of pro-inflammatory factors promoting Th17 differentiation: TGF-β, IL-17, IL-6, IL-23, and IL-21; ELISA detection of anti-inflammatory factors inhibiting Th17 differentiation: IFN-γ, IL-2, IL-4; Figure 2D For q-PCR detection of the expression of Cx43, PGC1α, Miro1, CD38 extracellular enzymes, and filamentous actin (F-αctin); Figure 2E For mitochondrial membrane potential detection, intracellular ATP activity level, mitochondrial energy metabolism (OCR), and Ca2+ content; Figure 2F It is Western Blot (WB) detection of the expression of mitochondrial migration-related proteins Cx43, PGC1α, Miro1, CD38 extracellular enzymes, and filamentous actin (F-αctin); Figure 2G For flow cytometry quantitative analysis of the mitochondrial exchange rate between mouse bone marrow mesenchymal stem cells (BMSCs) and mouse lung epithelial cells (MLE-12).

[0016] Figure 3 It is an animal experiment: Detect the pathological conditions of lung tissues of mice in each group by HE staining, calculate the survival rate of mice, draw a survival curve, and compare the survival rate differences between groups.

[0017] Figure 4 It is an animal experiment: Flow cytometry is used to detect the expression levels and proportions of immune cells in bronchoalveolar lavage fluid of mice in each group. Specific implementation manner

[0020] The present invention will be further described in detail below in conjunction with embodiments, but the implementation manners of the present invention are not limited thereto. Unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in the technical field. For the test methods without specific experimental conditions indicated in the following embodiments, they are generally carried out according to conventional experimental conditions or according to the experimental conditions recommended by the manufacturer. Unless otherwise specified, the reagents and raw materials used in the present invention can be obtained commercially.

[0021] Example 1 Correlation Analysis

[0022] (1) Patients with sepsis-induced acute lung injury admitted to the Department of Critical Care Medicine, the First Affiliated Hospital of Jinan University were selected as the experimental group, and patients without sepsis-induced acute lung injury were selected as the control group; bronchoalveolar lavage fluid was taken by fiberoptic bronchoscopy, and at least 3 times of fiberoptic bronchoscopic alveolar lavage treatment was performed during the treatment. Collection of bronchoalveolar lavage fluid: Select the middle lobe of the right lung or the lingular segment of the left upper lobe. After injecting 0.9% sodium chloride solution, use an appropriate negative pressure (100 mmHg, 1 mmHg = 0.133 kPa) to aspirate the bronchoalveolar lavage fluid. Exclusion criteria: ① Age < 18 years old; ② Complicated with severe pulmonary diseases such as cystic fibrosis; ③ Patients complicated with other severe infections or patients with rheumatoid arthritis, vasculitis, etc.; ④ Those with unqualified bronchoalveolar lavage fluid collection operations; ⑤ Those with ≤ 2 times of bronchoscopic alveolar lavage; ⑥ Those with contraindications to bronchial lavage treatment.

[0023] (2) ELISA was used to detect the levels of pro-inflammatory and anti-inflammatory factors in the sera of patients with sepsis-induced acute lung injury and healthy controls;

[0024] (3) Flow cytometry was used to detect Th17 cells (IL-17A+, CD4+, CD196(CCR6)+, RORγt) in the bronchoalveolar lavage fluid of patients with sepsis-induced acute lung injury and healthy controls.

[0025] In order to verify the role of Th17 cell activation in the bronchoalveolar lavage fluid of patients with acute lung injury and controls in sepsis-induced acute lung injury, the peripheral blood and bronchoalveolar lavage fluid of patients with sepsis-induced acute lung injury and non-sepsis patients were collected, ELISA detection was performed on the peripheral blood, and flow cytometry detection was performed on the bronchoalveolar lavage fluid. Since IL-17A+, CD4+, CD196(CCR6)+, RORγt are the markers of Th17 cells, the flow cytometry detection results showed that compared with patients with non-sepsis-induced acute lung injury, the ratios of CD196(CCR6)+RORγt+ and IL-17A+CD4+ in the Th17 cells of the bronchoalveolar lavage fluid of patients with sepsis-induced acute lung injury increased to about 9.14% and 21.4% respectively, as Figure 1 shown in A.

[0026] To further verify the differences in inflammatory levels in the sera of patients with sepsis-induced acute lung injury and non-sepsis patients, ELISA was used to detect the expression levels of TGF-β, IL-17, IL-6, IL-23, IL-21, IFN-γ, IL-2, and IL-4 in the peripheral blood sera of patients with acute lung injury and control patients. As Figure 1 shown in B, the expression levels of inflammation-related factors in the peripheral blood of patients with sepsis-induced acute lung injury were significantly increased. Therefore, it was further verified that Th17 cells and their markers and inflammatory factors had a high expression rate in patients with sepsis-induced acute lung injury. The above clinical findings and relevant domestic and foreign literature suggest that the Th17 level increases and the RORγt / STAT3 expression rate is high in sepsis-induced acute lung injury. Therefore, RORγt / STAT3 may promote the maturation and function of Th17 and play an important pro-inflammatory role in sepsis-induced acute lung injury.

[0027] In summary, these experimental results indicate that Th17 and its RORγt / STAT3 in the bronchoalveolar lavage fluid and peripheral blood of patients with sepsis-induced acute lung injury were significantly increased compared with the control group, and TGF-β, IL-17, IL-6, IL-23, and IL-21 were also significantly increased in patients with sepsis-induced acute lung injury, suggesting that RORγt / STAT3 may promote the maturation and function of Th17, promote the secretion of inflammatory factors, and further exacerbate sepsis-induced acute lung injury.

[0028] Example 2 Molecular mechanism of BMSCs upregulating miR-20b, inhibiting RORγt / STAT3, downregulating Th17 activation, and promoting mitochondrial transfer in sepsis-induced lung injury

[0029] By isolating and culturing CD4+ T cells from C57BL / 6J mice, CD4+ T cells were screened and identified using immunomagnetic beads and flow cytometry. For the obtained CD4+ T cells, the grouping -1 was as follows: A. CD4+ T cell group; B. OE-RORγt CD4+ T cell group; C. OE-NC-RORγt CD4+ T cell group; D. OE-miRNA-20b BMSCs + OE-RORγt CD4+ T cell group. In group B, RORγt was overexpressed; group C was the overexpression negative control (OE-NC) group; group D was the co-culture of BMSCs with overexpressed miRNA-20b and CD4+ T cells with overexpressed RORγt. This grouping was to verify that BMSCs upregulated the expression of miR-20b, inhibited RORγt / STAT3, and downregulated the activation of Th17.

[0030] To verify that healthy mitochondria in BMSCs are transferred to MLE-12 to achieve the effect of exogenous mitochondrial supplementation, a Transwell chamber was used, with BMSCs in the upper chamber and MLE-12 in the lower chamber for co-culture. For this purpose, multiple groups (Grouping-2) were set up as follows: A. LPS + MLE-12 group; B. BMSCs + LPS + MLE-12 group; C. OE-miR-20b-BMSCs + LPS + MLE-12 group; where in Group A, MLE-12 cells were co-cultured with lipopolysaccharide (LPS); in Group B, BMSCs, LPS, and MLE-12 were co-cultured; in Group C, BMSCs overexpressing miRNA-20b were co-cultured with LPS and MLE-12.

[0031] The binding sites of miRNA-20b to the RORγt / STAT3 target gene were predicted by miranda software and further verified by a dual-luciferase reporter assay. The experimental results showed that miRNA-20b could target and bind to inhibit RORγt / STAT3, as Figure 2A shown.

[0032] Compared with the CD4+T group, the proportion of Th17 cells in the OE-RORγt CD4+T group was significantly increased. Compared with the OE-RORγt CD4+T group, the proportion of Th17 cells in the OE-miRNA-20b BMSCs + OE-RORγt CD4+T group was significantly decreased. The experimental results Figure 2B shown.

[0033] ELISA was used to detect the pro-inflammatory factors promoting Th17 differentiation: TGF-β, IL-17, IL-6, IL-23, and IL-21; ELISA was used to detect the anti-inflammatory factors inhibiting Th17 differentiation: IFN-γ, IL-2, and IL-4. Compared with the CD4+T group, the proportion of pro-inflammatory factors in the OE-RORγt CD4+T group was significantly increased. Compared with the OE-RORγt CD4+T group, the proportion of pro-inflammatory factors in the OE-miRNA-20b BMSCs + OE-RORγt CD4+T group was significantly decreased. The experimental results Figure 2C shown.

[0034] To verify the mechanism promoting mitochondrial transfer, q-PCR was used to detect the expression of Cx43, PGC1α, Miro1, CD38 ectoenzyme, and filamentous actin (F-actin) in different groups of Group-2. Compared with the LPS+MLE-12 group, the expression of Cx43, PGC1α, Miro1, CD38 ectoenzyme, and filamentous actin (F-actin) in the BMSCs+LPS+MLE-12 group was significantly increased. Compared with the BMSCs+LPS+MLE-12 group, the expression of Cx43, PGC1α, Miro1, CD38 ectoenzyme, and filamentous actin (F-actin) in the OE-miR-20b-BMSCs+LPS+MLE-12 group was significantly increased. The experimental results Figure 2D are shown as follows.

[0035] In addition, the ATP activity level, mitochondrial energy metabolism (OCR), and NAD+ content in MLE-12 cells of different groups in Group-2 were detected using mitochondrial membrane potential. Compared with the LPS+MLE-12 group, the mitochondrial membrane potential in the BMSCs+LPS+MLE-12 group was significantly increased. Compared with the BMSCs+LPS+MLE-12 group, the mitochondrial membrane potential in the OE-miR-20b-BMSCs+LPS+MLE-12 group was significantly increased. Compared with the LPS+MLE-12 group, the mitochondrial content in the BMSCs+LPS+MLE-12 group was significantly decreased. Compared with the BMSCs+LPS+MLE-12 group, the mitochondrial content in the OE-miR-20b-BMSCs+LPS+MLE-12 group was significantly decreased. Compared with the LPS+MLE-12 group, the ATP activity level, mitochondrial energy metabolism (OCR), and NAD+ content in the BMSCs+LPS+MLE-12 group were significantly increased. Compared with the BMSCs+LPS+MLE-12 group, the ATP activity level, mitochondrial energy metabolism (OCR), and NAD+ content in the OE-miR-20b-BMSCs+LPS+MLE-12 group were significantly increased. The experimental results Figure 2E are shown as follows.

[0036] The expressions of mitochondrial migration-related proteins Cx43, PGC1α, Miro1, extracellular enzyme CD38, and filamentous actin (F-actin) in MLE-12 cells of different groups in Group 2 of WB detection were detected. Compared with the LPS+MLE-12 group, the expressions of Cx43, PGC1α, Miro1, extracellular enzyme CD38, and filamentous actin (F-actin) in the BMSCs+LPS+MLE-12 group were significantly increased. Compared with the BMSCs+LPS+MLE-12 group, the expressions of Cx43, PGC1α, Miro1, extracellular enzyme CD38, and filamentous actin (F-actin) in the OE-miR-20b-BMSCs+LPS+MLE-12 group were significantly increased. The experimental results Figure 2F are shown as follows.

[0037] Flow cytometry was used to quantitatively analyze the mitochondrial exchange rate between mouse bone marrow mesenchymal stem cells (BMSCs) and mouse lung epithelial cells (MLE-12) in different groups of Group 2. Compared with the LPS+MLE-12 group, the mitochondrial exchange rate between BMSCs and MLE-12 in the BMSCs+LPS+MLE-12 group was significantly increased. Compared with the BMSCs+LPS+MLE-12 group, the mitochondrial exchange rate in the OE-miR-20b-BMSCs+LPS+MLE-12 group was significantly increased. The experimental results Figure 2G are shown as follows.

[0038] Therefore, the above experiments can preliminarily illustrate the molecular mechanism of BMSCs upregulating miR-20b, inhibiting RORγt / STAT3, downregulating Th17 activation, and promoting mitochondrial transfer in sepsis-induced lung injury, which provides a strong basis for further verifying the efficacy of BMSCs in treating acute lung injury caused by sepsis in vivo.

[0039] Example 3 In Vivo Phenotype and Mechanism of BMSCs Upregulating miR-20b, Inhibiting RORγt / STAT3, Downregulating Th17 Activation, and Promoting Mitochondrial Transfer in Sepsis-Induced Lung Injury through Animal Experiments

[0040] (1) Establishment of acute lung injury induced by sepsis: C57BL / 6J mice were selected, and an acute lung injury (ALI) model was established by cecal ligation method. (Modeling method: After ligating the mouse at 50% or 75% of the cecal end, a 26G or 20G needle was used to penetrate the serosal surface of the cecal wall at the blind end opposite to the mesentery, and an appropriate amount of feces was extruded); Grouping: A. NC group; B. Model group; C. OE-miRNA-20b BMSCs group;

[0041] (2) Pathological examination, extract lung tissues for pathological examination: wet-to-dry lung ratio + HE staining of right lower lung tissue sections + pathological injury score of lung diseases (alveolar edema, pulmonary interstitial edema, infiltration of inflammatory cells, degree of alveolar wall thickening, atelectasis, formation of hyaline membranes); calculate the survival rate of mice and draw survival curves, and compare the differences in survival rates between groups.

[0042] (3) Collect peripheral blood and bronchoalveolar lavage fluid of mice, and detect Th17 cell markers by flow cytometry: IL-17A + CD4 + CD196 (CCR6) +, RORγt:

[0043] (4) ELISA detection of pro-inflammatory factors promoting Th17 differentiation: TGF-β, IL-17, IL-6, IL-23 and IL-21; ELISA detection of anti-inflammatory factors inhibiting Th17 differentiation: IFN-γ, IL-2, IL-4.

[0044] (5) WB and q-PCR detection: expressions of RORγt, STAT3, as well as GPX4, TrxR1, TrxR2 and mitochondrial migration-related proteins Cx43, PGC1α, Miro1, CD38 extracellular enzymes.

[0045] Detect the pathological conditions of lung tissues of mice in each group by HE staining, calculate the survival rate of mice and draw survival curves, and compare the differences in survival rates between groups. Compared with the NC group, the alveolar structure in the Model group was severely damaged, with a large number of inflammatory cell infiltrations, and the wet-to-dry lung ratio (W / D) was significantly increased. Compared with the Model group, the alveolar structure damage in the OE-miRNA-20b BMSCs group was reduced, the number of inflammatory cell infiltrations was decreased, and the wet-to-dry lung ratio (W / D) was significantly decreased. Compared with the NC group, the survival rate in the Model group was significantly decreased. Compared with the Model group, the survival rate in the OE-miRNA-20b BMSCs group was significantly increased. The experimental results Figure 3 are shown as follows.

[0046] Detect Th17 cell markers by flow cytometry: IL-17A + CD4 + CD196 (CCR6) +, RORγt. In the bronchoalveolar lavage fluid of mice, compared with the NC group, the proportion of Th17 in the Model group was significantly increased. Compared with the Model group, the proportion of Th17 in the OE-miRNA-20b BMSCs group was significantly decreased. The experimental results Figure 4 are shown as follows.

[0047] In summary, through the clinical problems of sepsis-induced acute lung injury discovered previously, as well as the results of cell and animal experiments, it can be confirmed that BMSCs up-regulate miR-20b, inhibit RORγt / STAT3, down-regulate Th17 activation, and promote mitochondrial transfer in the phenotypes and mechanisms of sepsis-induced lung injury.

[0048] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. Use of bone marrow mesenchymal stem cells in the preparation of a drug for treating sepsis-induced acute lung injury.

2. Use of miR-20b in the preparation of a drug for treating sepsis-induced acute lung injury.

3. Use of RORγt / STAT3 in the preparation of a drug for treating sepsis-induced acute lung injury.

4. Use of the miR-20b-RORγt / STAT3 signaling pathway in the preparation of a drug for treating sepsis-induced acute lung injury.

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