Pharmacological HIF-1 activation upregulates extracellular vesicle production synergistically with adiponectin through transcriptional induction and protein stabilization of T-cadherin

Fujii K., Fujishima Y., Kita S., et al. Pharmacological HIF-1 activation upregulates extracellular vesicle production synergistically with adiponectin through transcriptional induction and protein stabilization of T-cadherin. Scientific Reports 14, 3620 (2024); https://doi.org/10.1038/s41598-024-51935-6.Pharmacological activation of hypoxia-inducible factor 1 (HIF-1), a hypoxia-responsive transcription factor, has attracted increasing attention due to its efficacy not only in renal anemia but also in various disease models. Our study demonstrated that a HIF-1 activator enhanced extracellular vesicle (EV) production from cultured endothelial cells synergistically with adiponectin, an adipocyte-derived factor, through both transcriptional induction and posttranscriptional stabilization of an adiponectin binding partner, T-cadherin. Increased EV levels were observed in wild-type mice but not in T-cadherin null mice after consecutive administration of roxadustat. Adiponectin- and T-cadherin-dependent increased EV production may be involved in the pleiotropic effects of HIF-1 activators

Plasma xanthine oxidoreductase activity in Japanese patients with type 2 diabetes across hospitalized treatment

Yusuke Kawachi; Yuya Fujishima; Hitoshi Nishizawa; Hirofumi Nagao; Takashi Nakamura; Seigo Akari; Takayo Murase; Naohiro Taya; Kazuo Omori; Akimitsu Miyake; Shiro Fukuda; Mitsuyoshi Takahara; Shunbun Kita; Naoto Katakami; Norikazu Maeda; Iichiro Shimomura. Plasma xanthine oxidoreductase activity in Japanese patients with type 2 diabetes across hospitalized treatment. J Diabetes Investig. 2020

Skeletal Myoblast Cells Enhance the Function of Transplanted Islets in Diabetic Mice

Kado T., Tomimaru Y., Kobayashi S., et al. Skeletal Myoblast Cells Enhance the Function of Transplanted Islets in Diabetic Mice. Journal of Diabetes Research 2024, 5574968 (2024); https://doi.org/10.1155/2024/5574968.Islet transplantation (ITx) is an established and safe alternative to pancreas transplantation for type 1 diabetes mellitus (T1DM) patients. However, most ITx recipients lose insulin independence by 3 years after ITx due to early graft loss, such that multiple donors are required to achieve insulin independence. In the present study, we investigated whether skeletal myoblast cells could be beneficial for promoting angiogenesis and maintaining the differentiated phenotypes of islets. In vitro experiments showed that the myoblast cells secreted angiogenesis-related cytokines (vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and stromal-derived factor-1α (SDF-1α)), contributed to maintenance of differentiated islet phenotypes, and enhanced islet cell insulin secretion capacity. To verify these findings in vivo, we transplanted islets alone or with myoblast cells under the kidney capsule of streptozotocin-induced diabetic mice. Compared with islets alone, the group bearing islets with myoblast cells had a significantly lower average blood glucose level. Histological examination revealed that transplants with islets plus myoblast cells were associated with a significantly larger insulin-positive area and significantly higher number of CD31-positive microvessels compared to islets alone. Furthermore, islets cotransplanted with myoblast cells showed JAK-STAT signaling activation. Our results suggest two possible mechanisms underlying enhancement of islet graft function with myoblast cells cotransplantation: "indirect effects"mediated by angiogenesis and "direct effects"of myoblast cells on islets via the JAK-STAT cascade. Overall, these findings suggest that skeletal myoblast cells enhance the function of transplanted islets, implying clinical potential for a novel ITx procedure involving myoblast cells for patients with diabetes

HSP47 levels determine the degree of body adiposity

Shin J., Toyoda S., Okuno Y., et al. HSP47 levels determine the degree of body adiposity. Nature Communications 14, 7319 (2023); https://doi.org/10.1038/s41467-023-43080-x.Adiposity varies among individuals with the influence of diverse physiological, pathological, environmental, hormonal, and genetic factors, but a unified molecular basis remains elusive. Here, we identify HSP47, a collagen-specific chaperone, as a key determinant of body adiposity. HSP47 expression is abundant in adipose tissue; increased with feeding, overeating, and obesity; decreased with fasting, exercise, calorie restriction, bariatric surgery, and cachexia; and correlated with fat mass, BMI, waist, and hip circumferences. Insulin and glucocorticoids, respectively, up- and down-regulate HSP47 expression. In humans, the increase of HSP47 gene expression by its intron or synonymous variants is associated with higher body adiposity traits. In mice, the adipose-specific knockout or pharmacological inhibition of HSP47 leads to lower body adiposity compared to the control. Mechanistically, HSP47 promotes collagen dynamics in the folding, secretion, and interaction with integrin, which activates FAK signaling and preserves PPARγ protein from proteasomal degradation, partly related to MDM2. The study highlights the significance of HSP47 in determining the amount of body fat individually and under various circumstances

Low muscle quality in Japanese type 2 diabetic patients with visceral fat accumulation

Abstract Background Although obesity-related type 2 diabetes mellitus (T2DM) and sarcopenia in the elderly have been increasing worldwide, the associations among visceral fat accumulation, skeletal muscle indices (mass, strength, and quality) and cardiovascular diseases in T2DM remain poorly investigated. Methods We enrolled 183 Japanese T2DM inpatients (126 men, 57 women; mean age 64.7 ± 12.6 years, ± SD). The estimated-visceral fat area (eVFA) and skeletal muscle mass were measured by each device using bioelectrical impedance analysis method. We also measured grip strength by dynamometer and motor nerve conduction velocity (MCV). We analyzed the difference in skeletal muscle indices between T2DM patients with and without visceral fat accumulation, and examined the impact of skeletal muscle indices on cardiovascular diseases in patients with visceral fat accumulation. Results The prevalence of sarcopenia defined by the Consensus of Asian Working Group for Sarcopenia and low skeletal muscle mass were both lower in the visceral fat accumulation (+) group than in (−) group. However, the prevalence of weak hand grip strength was similar in the visceral fat accumulation (−) and (+) groups, indicating that considerable patients with visceral fat accumulation had weak grip strength in spite of fair skeletal muscle mass. Muscle quality [grip strength (kg)/arm muscle mass (kg)] was significantly lower in patients with visceral fat accumulation. Multiple regression analysis identified eVFA, MCV and sex as significant and independent determinants of muscle quality. In visceral fat accumulation (+) group, the patients with low muscle quality had longer duration of diabetes, lower eGFR, higher serum adiponectin, lower MCV and higher prevalence of cardiovascular diseases, compared to the patients with high muscle quality. Finally, sex- and age-adjusted models showed significant association between low muscle quality and cardiovascular diseases in all subjects (odds ratio 2.28, p = 0.012), especially in patients with visceral fat accumulation (odds ratio 2.72, p = 0.018). Conclusions T2DM patients with visceral fat accumulation had low muscle quality, and patients with low muscle quality were more affected with cardiovascular diseases