Following tendon injury, the development of fibrotic healing response impairs tendon function and restricts tendon motion. Peritendinous tissue fibrosis poses a major clinical problem in hand surgery. Communication between macrophages and tendon cells has a critical role in regulating the tendon-healing process. Yet, the mechanisms employed by macrophages to control peritendinous fibrosis are not fully understood. Here we analyze the role of macrophages in tendon adhesion in mice by pharmacologically depleting them. Such macrophage-depleted mice have less peritendinous fibrosis formation around the injured tendon compared with wild-type littermates. Macrophage-depleted mice restart fibrotic tendon healing by treatment with bone marrow macrophage-derived exosomes. We show that bone marrow macrophages secrete exosomal miR-21-5p that directly targets Smad7, leading to the activation of fibrogenesis in tendon cells. These results demonstrate that intercellular crosstalk between bone marrow macrophages and tendon cells is mediated by macrophage-derived miR-21-5p-containing exosomes that control the fibrotic healing response, providing potential targets for the prevention and treatment of tendon adhesion.
An increasing number of studies demonstrate that autophagy, an intrinsic mechanism that can degrade cytoplasmic components, is involved in the infection processes of a variety of pathogens. It can be hijacked by various viruses to facilitate their replication. In this study, we found that PRRSV infection significantly increases the number of double- or single-membrane vesicles in the cytoplasm of host cells in ultrastructural analysis. Our results showed the LC3-I was converted into LC3-II after virus infection, suggesting the autophagy machinery was activated. We further used pharmacological agents and shRNAs to confirm that autophagy promoted the replication of PRRSV in host cells. Confocal microscopy analysis showed that PRRSV inhibited the fusion between autophagosomes and lysosomes, suggesting that PRRSV induced incomplete autophagy. This suppression caused the accumulation of autophagosomes which may serve as replication site to enhance PRRSV replication. It has been shown that NSP2 and NSP3 of arterivirus are two components of virus replication complex. We also found in our studies that NSP2 colocalized with LC3 in MARC-145 cells by performing confocal microscopy analysis and continuous density gradient centrifugation. Our studies presented here indicated that autophagy was activated during PRRSV infection and enhanced PRRSV replication in host cells by preventing autophagosome and lysosome fusion.
BackgroundIn the 2014 Global initiative for chronic Obstructive Lung Disease guidelines, bronchiectasis was for the first time defined as a comorbidity of chronic obstructive pulmonary disease (COPD), and this change has been retained in the 2015 update, which emphasizes the influence of bronchiectasis in the natural history of COPD. The present meta-analysis was aimed at summarizing the impact of bronchiectasis on patients with COPD.MethodsDatabases including Embase, PubMed, and the Cochrane Central Register of Controlled Trials were searched comprehensively to identify all relevant human clinical studies published until August 2014. Bronchiectasis was confirmed either by computed tomography or high-resolution computed tomography. One or more clinicopathological or demographical characteristics, including age, sex, smoking history, daily sputum production, exacerbations, inflammatory biomarkers, lung function, and colonization by potentially pathogenic microorganisms (PPMs), were compared between COPD patients with and without bronchiectasis.ResultsSix observational studies with 881 patients were included in the meta-analysis. The mean prevalence of bronchiectasis in patients with COPD was 54.3%, ranging from 25.6% to 69%. Coexistence of bronchiectasis and COPD occurred more often in male patients with longer smoking history. Patients with COPD and comorbid bronchiectasis had greater daily sputum production, more frequent exacerbation, poorer lung function, higher level of inflammatory biomarkers, more chronic colonization by PPMs, and higher rate of Pseudomonas aeruginosa isolation.ConclusionIn spite of the heterogeneity between included studies and detectable publication bias, this meta-analysis demonstrated the impact of bronchiectasis in patients with COPD in all directions, indicating that coexistence of bronchiectasis should be considered a pathological phenotype of COPD, which may have a predictive value.
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