ABSTRACT
An effective therapeutic regimen for hepatic fibrosis requires a deep understanding of the pathogenesis mechanism. Hepatic fibrosis is characterized by activated hepatic stellate cells (aHSCs) with an excessive production of extracellular matrix. Although promoted activation of HSCs by M2 macrophages has been demonstrated, the molecular mechanism involved remains ambiguous. Herein, we propose that the vitamin D receptor (VDR) involved in macrophage polarization may regulate the communication between macrophages and HSCs by changing the functions of exosomes. We confirm that activating the VDR can inhibit the effect of M2 macrophages on HSC activation. The exosomes derived from M2 macrophages can promote HSC activation, while stimulating VDR alters the protein profiles and reverses their roles in M2 macrophage exosomes. Smooth muscle cell-associated protein 5 (SMAP-5) was found to be the key effector protein in promoting HSC activation by regulating autophagy flux. Building on these results, we show that a combined treatment of a VDR agonist and a macrophage-targeted exosomal secretion inhibitor achieves an excellent anti-hepatic fibrosis effect. In this study, we aim to elucidate the association between VDR and macrophages in HSC activation. The results contribute to our understanding of the pathogenesis mechanism of hepatic fibrosis, and provide potential therapeutic targets for its treatment.
Subject(s)
Humans , Hepatic Stellate Cells/pathology , Receptors, Calcitriol , Liver Cirrhosis/pathology , Macrophages/metabolismABSTRACT
【Objective】 To develop a spray-on membrane dressing for wound repair containing platelet rich plasma (PRP) sodium alginate (SA)/agarose(AG)/carboxymethyl chitosan (CMCS). 【Methods】 SA/AG/ CMCS were mixed in different proportions to prepare biodegradable quick setting spray (BQSS) by blending film method, and the film-forming time, moisture retention and compression resistance of the prepared BQSS were tested. Then PRP and BQSS were mixed in the proportion of 3∶7, 4∶6, 5∶5, 6∶4 and 7∶3 to prepare PRP-BQSS spray film dressings. The film-forming time, moisture retention, compressive strength, porosity and slow-release effect of growth factors of PRP-BQSS spray film dressings were studied. 【Results】 In the preparation of BQSS compound spray film solution, when SA, AG, CMCS and sterile distilled water were 0.6∶0.6∶0.6∶98.2g, the film-forming time (7.73±0.31) s, moisture retention (75. 54±3.03) % and compression resistance (791.00±68.02) g of the spray-film dressing were the best. The basic properties of PRP-BQSS spray-on film dressings and the release of growth factors show that PRP-BQSS spray-on film dressings can exist in different forms, and with the decrease of PRP concentration percentage, its film-forming time, moisturizing performance and compressive strength showed an upward trend. When the PRP content is 30%, the porosity of the dressing is the highest, about(84.34±0.90)%. The release of platelet-derived growth factor-AA(PDGF-AA), platelet factor-4(PF-4) and transforming growth factor beta (TGF-β) was in a slow upward trend, and the release of the three growth factors was higher than that of PRP group in 48 hours. 【Conclusion】 The preparation method of PRP-BQSS spray film dressing designed in this study is simple and mild, and can form a film quickly, with good biological properties and better growth factor inhibition and sustained-release effect.
ABSTRACT
Objective:To investigate the role of mitofusion 2 (Mfn2) in high glucose (HG)-induced endoplasmic reticulum stress (ERS) and apoptosis of podocytes.Methods:(1) Streptozocin was used to induce a diabetes mellitus (DM) rat model. Renal histopathological changes in rats were observed by HE staining. Expression of Mfn2 and CCAAT/enhancer-binding protein homologous protein (CHOP) in glomeruli was observed by immunohistochemistry. Protein levels of Mfn2, protein kinase RNA-like ER kinase (PERK), phospho(p)-PERK, and CHOP in glomeruli were analyzed by Western blotting. (2) Conditionally immortalized human podocytes (HPC) cultured in vitro were divided into control, mannitol (MA) and HG groups. Expression of Mfn2 was observed by immunofluorescence. Protein levels of Mfn2, p-PERK, PERK and CHOP in HPC were analyzed by Western blotting. Podocyte apoptosis in each group was evaluated by flow cytometry with AnnexinⅤ-PE/7AAD double staining method. (3) HPC were divided into control, HG, HG+Mfn2-Myc plasmid-transfected and HG+control plasmid-transfected groups. Protein levels of Mfn2, p-PERK, PERK and CHOP in HPC were analyzed by Western blotting. Expression of CHOP was observed by immunofluorescence. Mitochondrial membrane potential in each group was observed by mitochondrial membrane potential assay kit with JC-1. Podocyte apoptosis in each group was evaluated by flow cytometry with AnnexinⅤ-PE/7AAD double staining method. Results:(1) Compared with the control group, the glomerular mesangial matrix of the DM group rats was significantly proliferated, and the expression of Mfn2 was down-regulated with the expression of ERS-related proteins p-PERK/PERK and CHOP up-regulated (all P<0.05). (2) Compared with the control group, Mfn2 was down-regulated and p-PERK/PERK and CHOP were up-regulated in HPC of HG group (all P<0.05). Apoptosis of HPC was also increased in HG group. There was no significant difference in the above indicators between the control group and the mannitol group (all P>0.05). (3) Compared with the HG group, mitochondrial membrane potential of HPC was alleviated and apoptosis of HPC was decreased in HG+Mfn2-Myc plasmid-transfected group ( P<0.05). P-PERK/PERK and CHOP were down-regulated in HG+Mfn2-Myc plasmid-transfected group (both P<0.05). There was no significant difference in the above indicators between the HG group and the HG+control plasmid-transfected group (all P>0.05). Conclusions:Mfn2 down-regulation in HG-stimulated podocytes may induce ERS to increase apoptosis of podocytes. Up-regulation of Mfn2 can alleviate the HG-induced ERS and apoptosis in podocytes.