Acute lung injury (ALI) is characterized by uncontrolled inflammation, which can lead to respiratory distress syndrome and cause patient death. In this study, we sought to determine the role of sophoridine, a compound purified from sophora, in ALI. A mouse model of ALI was established by treating mice with LPS through nonexposed tracheal instillation. After LPS-induced mice were treated with sophoridine, LPS-induced alveolar wall thickening, alveolar interstitial inflammatory exudation and thickening, and the degree of pulmonary edema were found to be inhibited. Macrophages play an important role in inflammation, and in vitro experiments have demonstrated that sophoridine reduces the LPS-induced expression of inflammatory factors by macrophages, suggesting that sophoridine may inhibit lung inflammation in LPS-treated mice through reduces the secretion of inflammatory factors. Further, treatment with sophoridine up-regulated autophagy in macrophage cells in vitro and mouse lung tissues in vivo. LPS can bind to TLRs and activate the MyD88/NF-κB pathways, leading to increased inflammation in the pathogenesis of ALI. Our findings revealed that sophoridine down-regulated the expression of TLR4/MyD88/NF-κB and mTOR mRNA and protein in mouse pulmonary tissue. Collectively, these findings indicate that sophoridine may inhibit LPS-induced ALI by enhancing autophagy of macrophages and reducing inflammation.

Intrauterine adhesion (IUA) is one of the most prevalent reproductive system diseases in females. MicroRNAs (miRNAs) are reported to be master regulators in a variety of diseases, including IUA, but the role of microRNA-543 (miR-543) in IUA remains to be elucidated. In this study, we observed that miR-543 was downregulated in transforming growth factor-beta (TGF-β)-treated endometrial stromal cells (ESCs). Functionally, we observed that miR-543 suppressed the migration, epithelial-to-mesenchymal transition (EMT), and inhibited expression of extracellular matrix (ECM) proteins in TGF-β-treated ESCs. Mechanistically, MAPK1 is targeted by miR-543 after prediction and screening. A luciferase reporter assay demonstrated that miR-543 complementarily binds with the 3' untranslated region of mitogen-activated protein kinase 1 (MAPK1), and western blot analysis indicated that miR-543 negatively regulates MAPK1 protein levels. In addition, results from rescue assays showed that miR-543 inhibits the migration and EMT of TGF-β-treated ESCs by targeting MAPK1. In addition, we observed that miR-543 inactivates the Wnt/β-catenin signaling pathway through inhibiting the phosphorylation of MAPK1 and β-catenin. Finally, we confirmed that miR-543 represses migration, EMT and inhibits levels of ECM proteins in TGF-β-treated ESCs by targeting the Wnt/β-catenin signaling pathway. Our results demonstrated that miR-543 suppresses migration and EMT of TGF-β-treated ESCs by targeting the MAPK and Wnt/β-catenin pathways.

Acinetobacter baumannii (A. baumannii) is a common opportunistic nosocomial pathogen, which is able to produce biofilms on the surface of indwelling medical devices, and consequentially causes severe infections in clinical settings. In order to identify genes that involved in the biofilm formation of A. baumannii, the differential expression of genes between biofilms and planktonic cells was analyzed by RNAseq assay and validated in clinical isolates. The RNAseq data showed that 264 genes were up-regulated, while 240 genes were down-regulated in the biofilms of A. baumannii. Among them, the gene encoding alcohol dehydrogenase (ADH), a known molecule of bacterial quorum sensing (QS) system that plays a key role in biofilm formation bacteria, was one of the most up-regulated gene in both reference strains and clinical isolates. Functional studies using ADH inhibitor disulfiram and activator taurine further demonstrated that the presence of disulfiram significantly inhibit the cell growth, motility and biofilm formation, paralleled by a decreased expression of QS-related genes, including AbaI, A1S_0109, and A1S_0112, in a dose-dependent manner; vice versa, the addition of ADH activator taurine, and QS molecule C12- homoserine lactone synthase (HSL) led a dose-dependent increase of bacterial growth, motility and biofilm production, along with an increased expression of QS-related genes in both reference strains and clinical isolates of A. baumannii. These results suggested that the ADH was a key molecule able to modulate the QS system and promote the biofilm formation, growth and motility in A. baumannii.

Although estrogen has crucial functions for endometrium growth, the specific dose and underlying molecular mechanism in intrauterine adhesion (IUA) remain unclear. In this study, we aimed to investigate the effects of estrogen on epithelial-mesenchymal transition (EMT) in normal and fibrotic endometrium, and the role of estrogen and Wnt/β-catenin signaling in the formation of endometrial fibrosis. CCK-8 and immunofluorescence assay were performed to access the proliferation of different concentrations of estrogen on normal human endometrial epithelial cells (hEECs). qRT-PCR and western blot assay were utilized to explore the effect of estrogen on EMT in normal and fibrotic endometrium, and main components of Wnt/β-catenin signaling pathway in vitro. Hematoxylin and eosin and Masson staining were used to evaluate the effect of estrogen on endometrial morphology and fibrosis in vivo. Our results indicated that the proliferation of normal hEECs was inhibited by estrogen at a concentration of 30 nM accompanied by upregulation of mesenchymal markers and downregulation of epithelial markers. Interestingly, in the model of transforming growth factor β1 (TGF-β1)-induced endometrial fibrosis, the same concentration of estrogen inhibited the process of EMT, which might be partially mediated by regulation of the Wnt/β-catenin pathway. In addition, relatively high doses of estrogen efficiently increased the number of endometrial glands and reduced the area of fibrosis as determined by the reduction of EMT in IUA animal models. Taken together, our results demonstrated that an appropriate concentration of estrogen may prevent the occurrence and development of IUA by inhibiting the TGF-β1-induced EMT and activating the Wnt/β-catenin pathway.

Stem/progenitor cells have recently been demonstrated to play key roles in the maturation, injury repair, and regeneration of distinct organs or tissues. Porcine has spurred an increased interest in biomedical research models and xenotransplantation, owing to most of its organs share similarities in physiology, cellular composition and size to humans. Therefore, characterization of stem/progenitor cells in porcine organs or tissues may provide a novel avenue to better understand the biology and function of stem cells in humans. In the present study, potential stem/progenitor cells in conducting airway epithelium of a porcine lung were characterized by morphometric analysis of bromodeoxyuridine (BrdU) label-retaining cells (LRCs) during the maturation of the lung. The results showed a pseudostratified mucociliary epithelium comprised of basal, ciliated, goblet, and columnar cells in the conducting airway of a porcine lung. In addition, the majority of primary epithelial cells able to proliferate in vitro expressed keratin 5, a subpopulation of these keratin 5-positive cells, also expressed CD117 (c-Kit) or CD49f (integrin alpha 6, ITGA6), implying that they might be potential epithelial stem/progenitor cells in conducting airway of a porcine lung. Lineage tracing analysis with a BrdU-labeled neonatal piglet showed that the proportion of BrdU-labeled cells in conducting airways decreased over the 90-day period of lung maturation. The BrdU-labeled epithelial cells also expressed keratin 14, mucin 5AC, or prosurfactant protein C (ProSP-C); among them, the keratin 14-positive cells were the most frequent BrdU-labeled epithelial cell type as determined by immunohistochemical and immunofluorescence staining. This study may provide valuable information on the biology and function of epithelial stem/progenitor cells in conducting airway of pigs and humans.

The oxidative stresses are a major insult in pulmonary injury such as acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), two clinical manifestations of acute respiratory failure with substantially high morbidity and mortality. Mesenchymal stem cells (MSCs) hold a promise in treatments of many human diseases, mainly owing to their capacities of immunoregulation and antioxidative activity. The strong immunoregulatory role of human placental MSCs of fetal origin (hfPMSCs) has been previously demonstrated; their antioxidant activity, however, has yet been interrogated. In this report, we examined the antioxidative activity of hfPMSCs by accessing the ability to scavenge oxidants and radicals and to protect alveolar epithelial cells from antioxidative injury using both a cell coculture model and a conditioned culture medium (CM) of hfPMSCs. Results showed a comparable antioxidative capacity of the CM with 100 μ M of vitamin C (VC) in terms of the total antioxidant capacity (T-AOC), scavenging abilities of free radicals DPPH, hydroxyl radical (·OH), and superoxide anion radical (O 2 - ), as well as activities of antioxidant enzymes of SOD and GSH-PX. Importantly, both of the CM alone and cocultures of hfPMSCs displayed a protection of A549 alveolar epithelial cells from oxidative injury of 600 μ M hydrogen peroxide (H 2 O 2 ) exposure, as determined in monolayer and transwell coculture models, respectively. Mechanistically, hfPMSCs and their CM could significantly reduce the apoptotic cell fraction of alveolar epithelial A549 cells exposed to H 2 O 2 , accompanied with an increased expression of antiapoptotic proteins Bcl-2, Mcl-1, Nrf-2, and HO-1 and decreased proapoptotic proteins Bax, caspase 3, and Keap1, in comparison with naïve controls. Furthermore, hfPMSCs-CM (passage 3) collected from cultures exposed an inhibition of the Nrf2/Keap1/ARE signaling pathway which led to a significant reduction in caspase 3 expression in A549 cells, although the addition of Nrf2 inhibitor ML385 had no effect on the antioxidative activity of hfPMSCs-CM. These data clearly suggested that hfPMSCs protected the H 2 O 2 -induced cell oxidative injury at least in part by regulating the Nrf2-Keap1-ARE signaling-mediated cell apoptosis. Our study thus provided a new insight into the antioxidative mechanism and novel functions of hfPMSCs as antioxidants in disease treatments, which is warranted for further investigations.

Objective To investigate the influence of human placenta mesenchymal stem cells (hPMSCs) on the expression levels of inflammatory factors in the lung tissues of lipopolysaccharide (LPS)-induced acute lung injury (ALI) mice. Methods Six-week-old healthy C57BL/6 male mice were randomly divided into control group, ALI model group and hPMSC-treated group, with 8 mice in each group. LPS was trickled in ALI model group by the trachea. The hPMSC-treated mice were injected with hPMSCs by tail vein at 12 hours after administration of LPS. The control group was managed with the corresponding dose of normal saline. The surface markers of hPMSCs were identificated by flow cytometry. The mice were sacrificed after 24 hours, and the histopathological changes of lung tissues were detected by HE staining before and after injection of hPMSCs. The dry to wet mass ratio (W/D) and the myeloperoxidase (MPO) activity of the lung tissues were tested, and the levels of inflammatory factors in bronchoalveolar lavage fluid (BALF) were measured by ELISA, including tumor necrosis factor (TNF-α), interleukin-1 (IL-1) and interleukin-6 (IL-6). Results Phenotypic identification of hPMSCs showed the positive expression for CD105, CD90 and CD73, but negative expression for CD14, CD34, CD45. Compared with the control group, the pathological injury of the lung tissues was severe in the ALI model group, the W/D ratio and MPO activity in the lung tissues increased, and the levels of TNF-α, IL-1, and IL-6 in the BALF were significantly elevated. Compared with the ALI model group, the treatment with hPMSCs alleviated the lung pathological damage, decreased the W/D ratio and MPO activity in the lung tissues, and down-regulated the expressions of TNF-α, IL-1 and IL-6 in the BALF. Conclusion Treatment with hPMSCs can reduce the levels of inflammatory cytokines in the lung tissues and attenuate LPS-induced ALI.

MicroRNAs (miRNAs) being proved to be involved in the carcinogenesis of numerous tumors. MicroRNA-124 (miR-124), identified as a tumor suppressor, has been demonstrated to exert pivotal roles in multiple processes of tumorigenesis. The present study demonstrated that miR-124 was low-expressed in human hepatocellular carcinoma (HCC) tissues and cell lines. In addition, overexpression of miR-124 through infected with miR-124 lentivirus inhibited the proliferation and migration of HCC in vitro and tumorigenesis in vivo, whereas inhibition of miR-124 expression can reverse the process. Moreover, Baculoviral IAP Repeat Containing 3 (BIRC3) was identified as a target gene of miR-124. The BIRC3 mRNA expression was increased in HCC tissues and negatively correlated with miR-124 expression. Knockdown of BIRC3 recovered the miR-124-induced inhibiting effect on HCC progression. Furthermore, we found that up-regulation of miR-124 significantly inhibited p-P65, p-IκBα and c-Myc proteins expression. However, the effect of miR-124 up-regulation on HCC development was partly reversed by BIRC3 restoration. In conclusion, our data proved that miR-124 inhibits the proliferation and migration of HCC at least partly through targeting BIRC3 and regulating NF-κB signaling pathway, and it may be a therapeutic target for HCC prognosis.

目的 以pet41a质粒为载体骨架,通过酶切连接法构建crispr-cas9载体系统,建立一种简单有效的基因编辑载体,为研究细菌耐药基因的敲除提供方法. 方法 选择质粒pet41a、pwt-cas9和pgRNA,分析核酸序列,选择合适酶切位点.使用XhoⅠ和BgiⅡ两种限制性内切酶分别酶切pet41a和pwt-cas9,形成带有相同粘性末端的线性载体片段,回收并用T4 DNA连接酶连接,连接产物转化DH5α感受态细胞,转化菌涂布含卡那霉素的固体LB培养基平板进行阳性单克隆筛选并测序,构建的质粒命名为pet41-cas9.使用BgiⅡ和XbaⅠ两种限制性内切酶分别酶切pet41-cas9和pgRNA,经回收纯化、连接和转化后筛选阳性单克隆菌落并测序,重组质粒命名为pet41a-cas9-gRNA.分别将重组质粒pet41-cas9和pet41 a-cas9-gRNA转化BL-21(DE3),IPTG诱导后提取蛋白进行SDS-PAGE分析. 结果 测序证实质粒pet41-cas9、pet4 1a-cas9-gRNA连接正确,载体构建成功.重组质粒粒转染DE3后经IPTG诱导4h,表达相对分子质量为160×103的重组蛋白,与cas9蛋白理论分子质量相符. 结论 成功构建CRISPR-Cas9载体系统质粒pet41a-cas9-gRNA并表达重组cas9蛋白,为细菌基因的编辑研究奠定了实验基础.

S-phase kinase-associated protein 2 (SKP2), a potent oncogene was revealed to be upregulated in gastric cancer (GC) tissue samples, in which SKP2 was inversely correlated with microRNA (miR)‑508‑5p transcripts. In present study, the functional effect of miR‑508‑5p on SKP2 and its metastatic potential were investigated in SGC‑7901 GC cells. Significant downregulation of the miR‑508‑5p transcript was associated with the progression of GC. Furthermore, the overexpression of miR‑508‑5p was demonstrated to inhibit the proliferation, migration and invasion of SGC‑7901 cells, as well as induced cell apoptosis and cell cycle arrest at the G0/G1 phase in vitro. The overexpression of miR‑508‑5p was able to downregulate the expression of the SKP2 oncogene, through a mechanism by which miR‑508‑5p directly targeted the SKP2 gene. Thus, regulating transcriptional and post‑transcriptional SKP2 expression, as demonstrated using luciferase reporter assays, reverse transcription‑quantitative polymerase chain reaction analysis and immunoblotting assays. The results of the present study identified that miR‑508‑5p functionally affects the SKP2 gene and reduces metastatic potential in GC, suggesting a novel role of miR‑508‑5p in the regulation of SKP2 and cell cycle.

Increasing evidence suggests that aberrant expression of certain microRNAs (miRNAs) may participate in the genesis and progression of tumors. Several studies have indicated that miR-1247-5p plays different roles in various types of cancer cells. The effects of miR-1247-5p on human hepatocellular carcinoma (HCC) cells are elusive. In the present study, we investigated the effects of miR-1247-5p on the progression of HCC. The transcript of miR-1247-5p was markedly downregulated in clinical samples of patients with HCC and HCC cell lines, and ectopic overexpression of miR‑1247-5p markedly inhibited the proliferation and invasion of HepG2 cells, induced cell apoptosis in vitro, and suppressed the growth of transplanted tumors in vivo. Wnt3 was found to be a potential target of miR-1247-5p and overexpression of miR-1247-5p was able to significantly downregulate the expression of Wnt3 by directly targeting the 3'UTR of this gene, which was verified by luciferase reporter assay and western blotting. Furthermore, we found that the miR-1247-5p gene was hypermethylated in HepG2 cells, and the transcript of miR-1247-5p was increased significantly after treatment with the demethylation drug 5-azacytidine. These findings demonstrated that miR-1247-5p functions as a tumor suppressor in human HCC by targeting Wnt3 and that the expression of miR-1247-5p can be regulated by DNA methylation, which indicates that miR-1247-5p has the potential to be a therapeutic target as well as a diagnostic marker of HCC.

MicroRNAs (miRNAs) are small noncoding nucleotides that play major roles in the response of host immune cells. Autophagy plays a key role in activating the antimicrobial host defense against Mycobacterium tuberculosis (M. tuberculosis). Whether miRNAs specifically influence the activation of macrophage autophagy during M. tuberculosis infection is largely unknown. In the present study, we demonstrate that Mycobacterium bovis Bacillus Calmette-Guérin (BCG) infection of macrophages leads to increased expression of miR-144-3p, which targets autophagy-related gene 4a (ATG4a), to inhibit autophagy activation and antimicrobial responses to BCG. Overexpression of miR-144-3p significantly decreased both mRNA and protein levels of ATG4a, inhibited the formation of autophagosomes in RAW264.7 cells and increased intracellular survival of BCG. However, transfection with miR-144-3p inhibitor led to an increase in ATG4a levels, accelerated the autophagic response in macrophages, and decreased BCG survival in macrophages. The experimental results of this study reveal a novel role of miR-144-3p in inhibiting autophagy activation by targeting ATG4a and enhancing BCG infection, and provide potential targets for developing improved treatment.

The aim of our research is to identify potential genes associated with Ductal carcinoma in situ (DCIS) through microarrays. The microarray dataset GS54665 were downloaded from the GEO(Gene Expression Omnibus) database. Dysregulated genes were screened and their associations with DCIS was analyzed by comprehensive bioinformatics tools. A total of 649 differential expression genes were identified between normal and DCIS samples, including 224 up-regulated genes and 425 down-regulated genes. Biological process annotation and pathway enrichment analysis identified several DCIS-related signaling pathways. Finally, PPI network was constructed with String website in order to get the hub codes involved in Ductal carcinoma in situ. We thus concluded that Five genes: CDK1, CCNB2, MAD2L1, PPARG, ACACB were finally identified to participate in the regulation and serve as potential diagnosis signatures in in Ductal carcinoma in situ. Finally, complmentarity between CDK1 and three drugs, Aminophenazone, Pomalidomide and the Rosoxacin, implies novel pharmacological value of those drugs in breast cancer.

We attempted to analyze the effects of miR-1-3p and CCL2 on the proliferation, migration, and invasion of bladder cancer cells. A total of 18 pairs of bladder cancer tissues with corresponding adjacent tissues and the 6 cases of normal tissues were collected. The expressions of miR-1-3p and CCL2 in the cancer tissues were evaluated using quantitative real-time polymerase chain reaction and western blot. The relationship between miR-1-3p and CCL2 was assessed using luciferase reporter assay. The UM-UC-3 bladder cancer cells were transfected with CCL2 small interfering RNA and miR-1-3p mimics. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, colony formation assay, wound healing assay, Transwell assay, and the flow cytometry test were used to detect the proliferation, migration, invasion, and apoptosis of bladder cancer cells. Bladder cancer tissues had lower levels of miR-1-3p but higher levels of CCL2 than normal tissues (p<0.05). The transfection of miR-1-3p mimics and CCL2 small interfering RNA remarkably suppressed cell proliferation and invasion and promoted apoptosis of cells (p<0.05). Results of the luciferase reporter gene assay demonstrated that miR-1-3p targeted CCL2. MiR-1-3p suppresses the proliferation and invasion of urinary bladder cancer cells by targeting CCL2.

Lung cancer remains one of the most common cancer-associated mortalities worldwide, and platinum-based doublet chemotherapies are recommended as the first-line treatment for advanced non-small cell lung cancer (NSCLC). However, the frequent development of multidrug resistance, to cisplatin regimens in particular, is a major cause of chemotherapy failure in patients with aggressive NSCLC. Wnt/beta-catenin signaling and sex-determining regionY box 2 (Sox2) have been implicated in the development and progression and resistance to epidermal growth factor receptor-targeting therapy in lung cancer. The present study aimed to explore the effects of Wnt/beta-catenin and Sox2 signaling on the chemoresistance of cisplatin-resistant lung cancer cells by assessing the effects of Sox2 on Wnt/beta-catenin signaling activity, cell migration, invasion and clonogenicity, and susceptibility to cisplatin in lung adenocarcinoma A549 cells and cisplatin-resistant A549/DDP cells. The results demonstrated that an enforced expression of Sox2 led to inhibition of Wnt/beta-catenin signaling activity, potentially by upregulating glycogen synthase kinase 3 beta in A549 and A549/DDP cells. An overexpression of Sox2 promoted cell migration and invasion, in addition to enhancing the clonogenic capacity in A549 cells. Notably, knockdown Sox2 using short hairpin RNA led to an enhanced susceptibility of A549 and A549/DDP cells to cisplatin, along with increased cell apoptosis. The present study thus suggests that Sox2 may be an important regulator in development of chemoresistance of lung cancer cells and may be a novel therapeutic target for treatment chemoresistant lung cancer.

Epitope-based vaccine is a promising strategy for therapeutic vaccination against Helicobacter pylori (H. pylori) infection. A multivalent subunit vaccine containing various antigens from H. pylori is superior to a univalent subunit vaccine. However, whether a multivalent epitope-based vaccine is superior to a univalent epitope-based vaccine in therapeutic vaccination against H. pylori, remains unclear. In this study, a multivalent epitope-based vaccine named CWAE against H. pylori urease, neutrophil-activating protein (NAP), heat shock protein 60 (HSP60) and H. pylori adhesin A (HpaA) was constructed based on mucosal adjuvant cholera toxin B subunit (CTB), Th1-type adjuvant NAP, multiple copies of selected B and Th cell epitopes (UreA27-53, UreA183-203, HpaA132-141, and HSP60189-203), and also the epitope-rich regions of urease B subunit (UreB158-251 and UreB321-385) predicted by bioinformatics. Immunological properties of CWAE vaccine were characterized in BALB/c mice model. Its therapeutic effect was evaluated in H. pylori-infected Mongolian gerbil model by comparing with a univalent epitope-based vaccine CTB-UE against H. pylori urease that was constructed in our previous studies. Both CWAE and CTB-UE could induce similar levels of specific antibodies against H. pylori urease, and had similar inhibition effect of H. pylori urease activity. However, only CWAE could induce high levels of specific antibodies to NAP, HSP60, HpaA, and also the synthetic peptides epitopes (UreB158-172, UreB181-195, UreB211-225, UreB349-363, HpaA132-141, and HSP60189-203). In addition, oral therapeutic immunization with CWAE significantly reduced the number of H. pylori colonies in the stomach of Mongolian gerbils, compared with oral immunization using CTB-UE or H. pylori urease. The protection of CWAE was associated with higher levels of mixed CD4+ T cell (Th cell) response, IgG, and secretory IgA (sIgA) antibodies to H. pylori. These results indic ate that a multivalent epitope-based vaccine including Th and B cell epitopes from various H. pylori antigens could be a promising candidate against H. pylori infection.

Pulmonary fibrosis is a progressive lung disease that its pathogenic mechanism currently is incompletely understood. Toll-like receptor (TLR) signaling has recently been identified as a regulator of inflammation and pulmonary fibrosis. In addition, mesenchymal stem cells (MSCs) of different origins offer a great promise in treatment of idiopathic pulmonary fibrosis (IPF). However mechanisms of pathogenic roles of TLR signaling and therapeutic effects of MSCs in the IPF remain elusive. In present study, the involvement of TLR signaling and the therapeutic role of MSCs were interrogated in MyD88-deficient mice using human placental MSCs of fetal origins (hfPMSCs). The results showed an alleviated pulmonary inflammation and fibrosis in myeloid differentiation primary response gene 88 (MyD88)-deficient mice treated with bleomycin (BLM), accompanied with a reduced TGF-β signaling and production of pro-fibrotic cytokines, including TNF-α, IL-1β. An exposure of HLF1 lung fibroblasts, A549 epithelial cells and RAW264.7 macrophages to BLM led an increased expression of key components of MyD88 and TGF-β signaling cascades. Of interest, enforced expression and inhibition of MyD88 protein resulted in an enhanced and a reduced TGF-β signaling in above cells in the presence of BLM, respectively. However, the addition of TGF-β1 showed a marginally inhibitory effect on MyD88 signaling in these cells in the absence of BLM. Importantly, the administration of hfPMSCs could significantly attenuate BLM-induced pulmonary fibrosis in mice, along with a reduced hydroxyproline (HYP) deposition, MyD88 and TGF-β signaling activation, and production of pro-fibrotic cytokines. These results may suggest an importance of MyD88/TGF-β signaling axis in the tissue homeostasis and functional integrity of lung in response to injury, which may offer a novel target for treatment of pulmonary fibrosis.

Objective To investigate the therapeutic effect and mechanism of human placental mesenchymal stem cells of fetal origin (hfPMSCs) cultured in serum-free medium on mouse pulmonary fibrosis induced by bleomycin treatment. Methods Human hfPMSCs were cultured and identified by flow cytometry. Fifteen 6-week-old male SPF C57BL/6J mice were divided into 3 groups: bleomycin treatment group, hfPMSCs transplantation group and negative control group. Pulmonary fibrosis model was induced in the mice of bleomycin treatment group and hfPMSCs transplantation group with bleomycin (1 μg/L, 50 μL) via intratracheal instillation. The mice in negative control group were instilled with PBS (50 μL) through the same manner of the other two groups. Three days post-modelling, 200 μL containing 5×105 hfPMSCs were injected into hfPMSCs transplantation group via tail vein. All the mice were sacrificed at day 21 after modeling in batch. Lung tissues were collected for analyzing the pathological changes by HE staining and Masson staining as well as detecting collagen content. The total protein of lung tissues was extracted for observing the expressions of myeloid differentiation factor 88 (MyD88) and transforming growth factor-β (TGF-β); the level of TGF-β in sera was determined by Western blotting. Results The hfPMSCs possessed the morphology of mesenchymal stem cells and expressed the surface markers CD73, CD90 and CD105, but did not express CD14, CD34 and CD45. HE and Masson staining showed that hfPMSCs transplantation significantly reduced the degree of pulmonary fibrosis compared with bleomycin treatment group. The collagen content and the expression levels of MyD88 and TGF-β in bleomycin treatment group were obviously higher than those in hfPMSCs transplantation group and negative control group. Conclusion hfPMSCs possess the capability of alleviating pulmonary fibrosis by down-regulating the expressions of MyD88 and TGF-β.