Abstract Background: Silencing Mediator of Retinoid and Thyroid hormone receptors (SMRT; NCoR2) is a transcriptional corepressor which has been recognized as an important player in the regulation of hepatic lipogenesis and the somatic development in mouse embryo. SMRT protein is also widely expressed in the mouse connective tissues, for example adipocyte and skeletal muscle, and we recently reported that the mouse of global deletion of SMRT causes significant obesity which is independent from thyroid hormone signaling and thermogenesis. However, the tissue specific role of SMRT in skeletal muscle is still unelucidated. Methods: To clarify this, we took the gene targeting strategy for SMRT using CRISPR Cas9, and made the myogenic C2C12 clone which lacks SMRT protein (C2C12-SMRTKO; SKO). For this study, wild type C2C12 cell (WT) and SKO cell were cultured in differentiation medium (DMEM+2% horse serum) for 5-6 days, and analyses for gene expression compared two cell types were performed. Results: We found the significant up-regulations of muscle specific beta-oxidation related genes (ex. Ppar delta, Ampk2), and higher protein level of PGC-1A in the SKO cell, suggesting that SKO cell had similar gene profile to that of rodent skeletal muscle in the exercise test. On the other hand, confocal microscopic analysis showed SKO cell had decreased cell-fusion and loss of myotube, indicating that the morphology was similar to immature mouse myoblasts. Further gene analyses compared between WT and SKO cell demonstrated that SKO cell had higher expressions of myogenic markers; MyoD and Myogenin. However, interestingly, the lower expressions of muscle constitutive genes; MHC, Actin, and Alpha-dystrobrevin were found in the SKO cell. These data indicate that the SKO cell has incomplete muscle fiber formation. Conclusion: Taken together, we demonstrate that SMRT works as a pivotal transcriptional mediator for both beta-oxidation and the process of myotube formation in C2C12 cell. Further inquiry for the cause of sarcopenia-like phenotype manifested in the SKO cell will be needed.
Glomerular lipidosis is a disease characterized by lipid accumulation in mesangial cells but that has not been fully investigated in avian species. We examined four wild and two laboratory-reared Japanese rock ptarmigans (Lagopus mutus japonicus)--an endangered avian species--presenting vacuolar deposits in the glomeruli. All cases had vacuolar deposits in the glomeruli. In the wild cases, fewer than 30% of all glomeruli were affected, compared with more than 90% in the laboratory-reared cases. In the wild cases, most deposits were mild and restricted to the mesangial areas of glomeruli. In the laboratory-reared cases, nearly all of the deposits covered entire glomeruli. Electron microscopy of mild deposits revealed vacuoles in the cytoplasm of mesangial cells. These vacuoles were positive for Sudan III, Sudan black B, oil red O, Nile blue, periodic acid-Schiff, Schultz test, and digitonin stain and were negative for performaric acid-Schiff stains. Based on these results, we diagnosed the glomerular lesion as glomerular lipidosis caused by uptake of low-density lipoprotein in mesangial cells. Except for one wild case, all cases exhibited renal tubular oxalosis. The severity of tubular oxalosis tended to be related to the severity of glomerular lipidosis: In cases of mild glomerular lipidosis, tubular oxalosis was also mild or absent. We therefore diagnosed the primary lesion as glomerular lipidosis accompanied by tubular oxalosis. The four wild cases came from different zones and therefore had no opportunities to interbreed and no common relatives. We believe these data support the hypothesis that glomerular lipidosis is a disease of the general population ofJapanese rock ptarmigans. This is the first report of glomerular lipidosis accompanied by renal tubular oxalosis in an avian species.
StarD7 is a phosphatidylcholine (PC)-specific lipid transfer protein essential for the maintenance of mitochondrial PC composition, morphogenesis, and respiration. Here, we studied the role of StarD7 in skeletal myoblast differentiation using mouse myoblast C2C12 cells and human primary myoblasts. Immunofluorescence and immuno-electron microscopy revealed that StarD7 was distributed in the cytosol, inner mitochondria space, and outer leaflet of the outer mitochondrial membrane in C2C12 cells. Unlike human kidney embryonic cell line HEK293 cells, the mitochondrial proteinase PARL was not involved in the processing and maturation of StarD7 in C2C12 cells. StarD7 was constantly expressed during myogenic differentiation of C2C12 cells. The siRNA-mediated knockdown of StarD7 in C2C12 cells and human primary myoblasts significantly impaired myogenic differentiation and reduced the expression of myomaker, myomerger and PGC-1α. The reduction in mitochondrial PC levels and oxygen consumption rates, decreased expression of myomaker, myomerger and PGC-1α, as well as impaired myogenic differentiation, were completely restored when the protein was reintroduced into StarD7-knockout C2C12 cells. These results suggest that StarD7 is important for skeletal myogenesis in mammals.
Abstract Background Health information exchange (HIE) may improve diagnostic accuracy, treatment efficacy, and safety by providing treating physicians with expert advice. However, most previous studies on HIE have been observational in nature. Objectives To examine whether collaboration between specialists and general practitioners (GPs) in rural areas via HIE can improve outcomes among patients at low-to-moderate risk of cardiovascular disease, kidney disease, and stroke. Methods In this randomized controlled trial, the Miyagi Medical and Welfare Information Network was used for HIE. We evaluated the clinical data of 1,092 patients aged ≥65 years living in the rural areas of the Miyagi Prefecture and receiving care from GPs only. High-risk patients were immediately referred to specialists, whereas low-to-moderate risk patients were randomly assigned to an intervention group in which GPs were advised by specialists through HIE (n = 518, 38% male, mean age = 76 ± 7 years) or a control group in which GPs received no advice by specialists (n = 521, 39% male, mean age = 75 ± 7 years). Results In the intention-to-treat analysis, all-cause mortality and cumulative incidence of serious adverse events (e.g., hospital admission or unexpected referral to specialists) did not differ between the groups. However, per-protocol analysis controlling for GP adherence with specialist recommendations revealed significantly reduced all-cause mortality (p = 0.04) and cumulative serious adverse event incidence (p = 0.04) in the intervention group compared with the control group. Conclusion HIE systems may improve outcomes among low-to-moderate risk patients by promoting greater collaboration between specialists and GPs, particularly in rural areas with few local specialists.
