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Abstract Secondary lung injury after SCI is a major cause of patient mortality, with apoptosis playing a key role. This study aimed to explore the impact of treadmill training and miR145-5p on the MAPK/Erk signaling pathway and apoptosis in rats with complete SCI. SD rats were used to establish T10 segmental complete SCI models and underwent treadmill training 3, 7, or 14 days postinjury. Various techniques including arterial blood gas analysis, lung wet/dry weight ratio, HE staining, immunofluorescence staining, immunohistochemical staining, qRT-PCR, and Western blotting were employed to assess alterations in lung function and the expression levels of crucial apoptosis-related factors. In order to elucidate the specific mechanism, the impact of miR145-5p on the MAPK/Erk pathway and its role in apoptosis in lung cells were confirmed through miR145-5p overexpression and knockdown experiments. Following spinal cord injury (SCI), an increase in apoptosis, activation of the MAPK/Erk pathway, and impairment of lung function were observed in SCI rats. Conversely, treadmill training resulted in a reduction in alveolar cell apoptosis, suppression of the MAPK/Erk pathway, and enhancement of lung function. The gene MAP3K3 was identified as a target of miR145-5p. The influence of miR145-5p on the MAPK/Erk pathway and its impact on apoptosis in alveolar cells were confirmed through the manipulation of miR145-5p expression levels. The upregulation of miR145-5p in spinal cord injury (SCI) rats led to a reduction in MAP3K3 protein expression within lung tissues, thereby inhibiting the MAPK/Erk signaling pathway and decreasing apoptosis. Contrarily, rats with miR145-5p knockdown undergoing treadmill training exhibited an increase in miR145-5p expression levels, resulting in the inhibition of MAP3K3 protein expression in lung tissues, suppression of the MAPK/Erk pathway, and mitigation of lung cell apoptosis. Ultimately, the findings suggest that treadmill training may attenuate apoptosis in lung cells post-spinal cord injury by modulating the MAP3K3 protein through miR145-5p to regulate the MAPK/Erk signaling pathway.

Objective: To investigate the effect of miR145-5P overexpression on the polarization imbalance of synovial macrophages in patients with rheumatoid arthritis (RA). Methods: Human mononuclear cells (THP-1) at logarithmic growth stage were induced into M1-type macrophages, and RA synovial fibroblasts M1-type macrophages were co-cultured into synovial macrophages. Synovial macrophages were divided into four groups :RA group (blank group), TGF-β1 group (model group) and miR145-5P overexpression group (TGF-β1+ miR145-5P mimics group) and miR145-5P overexpression negative control group (TGF-β1+ miR145-5P-mimics -NC group). The blank group did not receive any treatment, and the other three groups were induced by TGF-β1 in the medium for 48 h. Transfection miR145-5p mimic and miR145-5P-mimics-NC were added to co-culture medium, and IL-6, IL-6 and IL-6 of synovial macrophages were detected by ELISA.CD163 expression. Rt-qpcr was used to detect miR145-5p mRNA, TGF-β1mRNA, Smad3mRNA,Smad7mRNA expression level. The expression of TGF-β1/Smads pathway related proteins was detected by Western Blotting. Results: Compared with blank group, IL-6 level was up-regulated (P<0.01), and CD163 level was down-regulated in model group(P<0.05), suggesting that TGF-β1 could induce intensified immune inflammatory response. Compared with the negative miR145-5P overexpression control group and model group, The expression of miR145-5P overexpression group molecule CD163 was significantly increased by ELISA(P<0.01), and the expression of inflammatory factor IL-6 was decreased (P<0.05). PCR showed that miR145-5P mRNA expression level was significantly increased in miR145-5P overexpression group,Smad3 mRNA and TGF-β1 mRNA were significantly decreased, and Smad7 mRNA was significantly increased (P<0.01). WB method showed that the anti-inflammatory protein Smad7 was significantly increased, while TGF-β1 and Smad3 were significantly decreased (P<0.01). Transwell chamber results confirmed that miR145-5P overexpression group significantly reduced macrophage invasion (P<0.01). Correlation analysis showed that miR145-5P was negatively correlated with Smad3 and positively correlated with Smad7 (P<0.01). Conclusion: miR145-5P may inhibit macrophage polarization in RA patients by targeting Smad3 protein, negatively regulating TGF-β1/Smads pathway, and alleviating immune inflammation. [ABSTRACT FROM AUTHOR]

Hepatopulmonary syndrome (HPS) is a triad of advanced liver disease, intrapulmonary vasodilatation and arterial hypoxemia. Increasing evidence shows that HPS is associated with pulmonary microvascular hyperplasia. The aim of this work was to investigate the underlying mechanism of miR-145 in regulating the proliferation of pulmonary microvascular endothelial cells (PMVECs) and angiogenesis in HPS via plasminogen activator inhibitor-1 (PAI-1). To test this, morphology score and number of pulmonary microvascular were assessed in lung tissues from rats with HPS by Hematoxylin and Eosin (H&E) staining. Expression levels of PAI-1 were assessed in lung tissues from HPS rats, as well as in PMVECs treated with HPS rat serum. We also selected the putative microRNA binding site on PAI-1 by bioinformatics analysis. Then, miR145-3p and miR145-5p expression levels in the lungs and PMVECs of rats were detected by qRT-PCR because miR145-5p is a microRNA binding site on PAI-1. In addition, the effects of miR-145-5p regulation on PAI-1 were examined by upregulation and downregulation of miR-145-5p and specific lentivirus transfection was used to overexpress and knockdown PAI-1 to assess PAI-1 function on PMVECs proliferation. Our data showed that levels of PAI-1 expression in lung tissue of rats increased significantly when rats were treated with common bile duct ligation. We found that levels of miR-145-5p were frequently downregulated in HPS tissues and cell lines, and overexpression of miR-145-5p dramatically inhibited PMVECs proliferation. We further verified PAI-1 as a novel and direct target of miR-145-5p in HPS. MiR-145-5p inhibits PAI-1 synthesis and the expression changes of PAI-1 directly affect the proliferation of PMVECs. We concluded that miR-145-5p negatively regulates PMVEC proliferation through PAI-1 expression. In addition, overexpression of miR-145-5p may prove beneficial as a therapeutic strategy for HPS treatment.

Hepatopulmonary syndrome (HPS) is a triad of advanced liver disease, intrapulmonary vasodilatation and arterial hypoxemia. Increasing evidence shows that HPS is associated with pulmonary microvascular hyperplasia. The aim of this work was to investigate the underlying mechanism of miR-145 in regulating the proliferation of pulmonary microvascular endothelial cells (PMVECs) and angiogenesis in HPS via plasminogen activator inhibitor-1 (PAI-1). To test this, morphology score and number of pulmonary microvascular were assessed in lung tissues from rats with HPS by Hematoxylin and Eosin (H&E) staining. Expression levels of PAI-1 were assessed in lung tissues from HPS rats, as well as in PMVECs treated with HPS rat serum. We also selected the putative microRNA binding site on PAI-1 by bioinformatics analysis. Then, miR145-3p and miR145-5p expression levels in the lungs and PMVECs of rats were detected by qRT-PCR because miR145-5p is a microRNA binding site on PAI-1. In addition, the effects of miR-145-5p regulation on PAI-1 were examined by upregulation and downregulation of miR-145-5p and specific lentivirus transfection was used to overexpress and knockdown PAI-1 to assess PAI-1 function on PMVECs proliferation. Our data showed that levels of PAI-1 expression in lung tissue of rats increased significantly when rats were treated with common bile duct ligation. We found that levels of miR-145-5p were frequently downregulated in HPS tissues and cell lines, and overexpression of miR-145-5p dramatically inhibited PMVECs proliferation. We further verified PAI-1 as a novel and direct target of miR-145-5p in HPS. MiR-145-5p inhibits PAI-1 synthesis and the expression changes of PAI-1 directly affect the proliferation of PMVECs. We concluded that miR-145-5p negatively regulates PMVEC proliferation through PAI-1 expression. In addition, overexpression of miR-145-5p may prove beneficial as a therapeutic strategy for HPS treatment., Competing Interests: Competing interestsThe authors declare no competing or financial interests., (© 2019. Published by The Company of Biologists Ltd.)