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Exceptional Diseases from the Orbit.
BACKGROUND β-cell dysfunction is one of the core pathogenetic mechanisms of type 2 diabetes mellitus (T2DM). However, there are currently no effective therapeutic strategies to preserve β-cell mass and function. The role of islet macrophage phenotype reprogramming in β-cell dysfunction has attracted great attention. Given that advanced glycation end products (AGEs) are major pathogenic factors in T2DM, we investigated the effect of AGEs on macrophage activation and their role in β-cell dysfunction. METHODS We examined cytokine secretion, M1 and M2 macrophage-associated marker expression and MAPK phosphorylation levels in AGEs-stimulated macrophages. MIN6 cells were cocultured with AGEs-pretreated macrophages to study the effect of AGEs-induced macrophage activation on β-cell dysfunction. RESULTS We found that AGEs treatment significantly enhanced macrophage secretion of proinflammatory cytokines. The expression of M1 macrophage markers, such as iNOS and the surface marker CD11c, was significantly upregulated, whereas the expression of M2 macrophage markers, such as Arg1 and CD206, was reciprocally downregulated upon AGEs stimulation. AGEs treatment predominantly activated the MAPK pathway, and the inhibition of the MAPK pathway partially attenuated the AGEs-induced polarization of macrophages. In addition, coculture with AGEs-pretreated macrophages significantly inhibited the expression of molecules involved in β-cell function and was accompanied by the impairment of glucose-stimulated insulin secretion (GSIS) in MIN6 cells. CONCLUSION AGEs enhance the expression of proinflammatory molecules by activating the MAPK pathway. Moreover, these data imply that AGEs induce macrophage M1 phenotype polarization but restrain M2 polarization, which might contribute to β-cell dysfunction in the pathogenesis of T2DM. Skeletal muscle is divided into type 1 and type 2 fibers. Type 1 fibers are rich in mitochondria, have high oxidative metabolism, and are resistant to fatigue. Muscle-specific overexpression of peroxisome proliferator-activated receptor (PPAR)δ drastically increases the number of type 1 fibers. We focused on oleic acid, an omega-9 monounsaturated fatty acid, as a factor that activates PPARδ. In this study, we examined the effects of oleic acid on the muscle fiber type of C2C12 myotubes and its relationship with PPARδ. Our results showed that oleic acid treatment increased the levels of myosin heavy chain (MyHC)1, a known type 1 fiber marker, as well as mitochondrial mass and maximum respiration in C2C12 cells. To confirm the relationship between PPARδ activation and oleic acid-induced MyHC1 increase, we examined the effects of oleic acid in PPARδ knockdown C2C12 myoblasts. We found that oleic acid supplementation increased the mRNA expression of MyHC1 in PPARδ-knockdown C2C12 cells. Our data suggest that oleic acid increases type 1 fiber levels in C2C12 myotubes in a PPARδ-independent manner. BACKGROUND RapaLink-1 is a third generation mammalian target of rapamycin (mTOR) inhibitor and displays superior inhibitory effect on mTOR complex 1 (mTORC1). mTOR pathway is known to block autophagy and inhibition of it can protect thrombosis-related diseases including atherosclerosis, antiphospholipid syndrome (APS) and stroke. The objective of this study was to investigate whether RapaLink-1 could exert anti-thrombotic effects on APS via improving autophagy. METHODS BALB/c mice were injected with monoclonal anti-beta-2-GPI (β2GPI) antibodies to induce APS in vivo, and anti-β2GPI antibodies together with anticardiolipin (aCL) antibodies in mice serum were assessed. The aortas of mice were isolated, and oil red and haematoxylin and eosin (HE) staining were used for thrombus morphology. The levels of LC3B and CD68 were quantified. Human monocyte cell line THP-1 was stimulated with oxidized low-density lipoprotein (ox-LDL) and treated with RapaLink-1 in vitro. The cell viability, LDH activity, apoptosis rate and rate of fate-positive cells were detected. LC3 expression was quantified by immunofluorescence. Western blot was utilized to assess the protein expression of LC3-І, LC3-П, Beclin-1 and p62. Foscenvivint datasheet RESULTS The size of arterial thrombus plaque together with the level of anti-β2GPI antibodies and aCL was reduced by RapaLink-1. Immunostaining protocols confirmed that the application of RapaLink-1 inhibited plaque initiation and progression while decreased the extent of macrophage infiltration and enhanced the autophagy process. In vitro cultured THP-1 macrophages exposed to ox-LDL study showed that RapaLink-1 prevented cell apoptosis and enhanced autophagy of macrophages, indicated by the increasing expression of autophagy-related protein and morphological character under electron microscopy. CONCLUSION Our results revealed that Rapalink-1 has a potential to inhibit the formation of thrombus plaque in APS and these effects were dependent on facilitating cell autophagy both in vivo and in vitro. The family Filoviridae contains many important human viruses, including Marburg virus (MARV) and Ebola virus (EBOV). Měnglà virus (MLAV), a newly discovered filovirus, is considered a potential human pathogen. The VP30 C-terminal domain (CTD) of these filoviruses plays an essential role in virion assembly. In common with other filoviruses, MLAV VP30 CTD mainly exists as a dimer in solution. In this work, we determined the crystal structure of recombinant MLAV VP30 CTD monomer, verifying that C-terminal helix-7 (H7) is critical for the dimerization process. This study provides a preliminary model for investigation of MLAV VP30 CTD as an anti-filovirus drug development target. The occurrence and development of osteoclasts can directly affect the severity of bone destruction in middle ear cholesteatoma. At the same time, cell communication between keratinocytes and fibroblasts can stimulate osteoclast differentiation. However, the molecular mechanism of osteoclast differentiation in cholesteatoma is still poorly understood. In this study, we try to isolate the exosomes of keratinocytes from patients with middle ear cholesteatoma, and explore the effects of keratinocyte-derived exosomes (Ker-Exo) on osteoclast differentiation by co-culturing Ker-Exo with fibroblasts and osteoclast precursor cells. As a result, we confirmed that Ker-Exo primed fibroblasts can up-regulate the expression of RANKL and promote osteoclast differentiation. We revealed that the effect of Ker-Exo depened on its miRNA-17 conponent. Analysis confirmed that miRNA-17 was down-regulated in Ker-Exo, and they can increase RANKL level in fibroblasts, thus promoting the differentiation of osteoclasts. In conclusions, we provide evidence that exosomes miRNA-17 secreted by keratinocytes in patients with middle ear cholesteatoma can up-regulate the expression of RANKL in fibroblasts and induce osteoclast differentiation.
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