Effect of sodium-glucose cotransporter 2 (SGLT2) inhibition on weight loss is partly mediated by liver-brain-adipose neurocircuitry.

Sodium-glucose cotransporter 2 (SGLT2) inhibitors have both anti-diabetic and anti-obesity effects. However, the precise mechanism of the anti-obesity effect remains unclear. We previously demonstrated that the glycogen depletion signal triggers lipolysis in adipose tissue via liver-brain-adipose neurocircuitry. In this study, therefore, we investigated whether the anti-obesity mechanism of SGLT2 inhibitor is mediated by this mechanism. Diet-induced obese mice were subjected to hepatic vagotomy (HVx) or sham operation and loaded with high fat diet containing 0.015% tofogliflozin (TOFO), a highly selective SGLT2 inhibitor, for 3 weeks. TOFO-treated mice showed a decrease in fat mass and the effect of TOFO was attenuated in HVx group. Although both HVx and sham mice showed a similar level of reduction in hepatic glycogen by TOFO treatment, HVx mice exhibited an attenuated response in protein phosphorylation by protein kinase A (PKA) in white adipose tissue compared with the sham group. As PKA pathway is known to act as an effector of the liver-brain-adipose axis and activate triglyceride lipases in adipocytes, these results indicated that SGLT2 inhibition triggered glycogen depletion signal and actuated liver-brain-adipose axis, resulting in PKA activation in adipocytes. Taken together, it was concluded that the effect of SGLT2 inhibition on weight loss is in part mediated via the liver-brain-adipose neurocircuitry.

Betatrophin expression is promoted in obese hyperinsulinemic type 2 but not type 1 diabetic mice.

Regeneration of pancreatic ß-cell mass benefits both type 1 and type 2 diabetic patients. A recent study identified betatrophin as a ß-cell proliferation factor. However, the expressional regulation of betatrophin remains less defined. In this study, we aimed to clarify the regulation of betatrophin expression in obese type 2 vs. type 1 diabetes model animals. We experimented type 2 diabetes models, diet-induced-obesity (DIO) mice and db/db mice, and type 1 diabetes models, C57B6 mice receiving streptozotocin (STZ) or 70% pancreatectomy to destroy or remove ß-cells. Serum betatrophin levels and betatrophin mRNA expressions in the liver, white adipose tissue (WAT) and brown adipose tissue (BAT) were measured. In DIO mice and db/db mice, serum betatrophin and betatrophin mRNA expressions in the liver, WAT and BAT were elevated in parallel with increases in body weight and plasma insulin. These elevated betatrophin mRNA expressions were not altered by treatment with SGLT2 inhibitor that ameliorated hyperglycemia. In pancreatectomized mice, betatrophin expression in WAT decreased in parallel with reductions in weight and insulin. In STZ-treated mice, betatrophin expressions in the liver, WAT and BAT were reduced. However, when the mouse liver slices were cultured with STZ, betatrophin expression was significantly reduced, indicating a direct action of STZ on the liver. These results indicate that the expression of betatrophin is upregulated in the liver, WAT and BAT in obese hyperinsulinemic type 2 diabetes but decreased in WAT in hypoinsulinemic type 1 diabetes, suggesting its positive correlation with body weight and plasma insulin but not blood glucose.

Paraventricular NUCB2/nesfatin-1 is directly targeted by leptin and mediates its anorexigenic effect.

An adipokine leptin plays a central role in the regulation of feeding and energy homeostasis via acting on the hypothalamus. However, its downstream neuronal mechanism is not thoroughly understood. The neurons expressing nucleobindin-2 (NUCB2)-derived nesfatin-1 in the hypothalamic paraventricular nucleus (PVN) have been implicated in feeding and energy homeostasis. The present study aimed to explore the role of PVN NUCB2/nesfatin-1 in the leptin action, by using adeno-associated virus (AAV) vectors encoding shRNA targeting NUCB2 (AAV-NUCB2-shRNA). Leptin directly interacted and increased cytosolic Ca(2+) in single neurons isolated from the PVN, predominantly in NUCB2/nesftin-1-immunoreactive neurons. Treatment with leptin in vivo and in vitro markedly increased NUCB2 mRNA expression in the PVN. Peripheral and central injections of leptin failed to significantly inhibit food intake in mice receiving AAV-NUCB2. These results indicate that PVN NUCB2/nesfatin-1 is directly targeted by leptin, and mediates its anorexigenic effect.

Spatiotemporal evolution and influence mechanism of the carbon footprint of energy consumption at county level in the Yellow River Basin.

Implementing emission reduction policies at county level is important to realize high-quality development in the Yellow River Basin and achieve national "carbon peaking" and "carbon neutrality" goals. Based on remote-sensing data of night light, net primary productivity, and land use, the present study utilized the light­carbon conversion and carbon footprint measurement models to quantify the carbon footprint of energy consumption. An exploratory spatiotemporal data analysis method was implemented to analyze the spatiotemporal evolution path. Panel quantile regression and spatiotemporal transition-nested models were used to reveal the influence mechanism of the spatiotemporal evolution of the carbon footprint. The following results were obtained. (1) The carbon footprint of counties increased from 2001 to 2020. Counties with high­carbon footprint diffused around the "one center and two axes". Carbon-deficit counties exhibited a diffused trend towards the west. In 2020, 506 counties exhibited carbon deficits, and the carbon balance of the ecosystem was severely unbalanced. (2) The carbon footprint showed evident path dependence and Matthew effect. The high­carbon footprint lock-in area comprising 177 counties is a challenging zone for governance. The 86 counties that exhibit carbon footprint changes are the key zones to drive the carbon footprint changes in the Basin. The change direction of the county's carbon footprint type, with evident spatial correlation characteristics, is in accordance with adjacent counties. (3) The carbon footprint spatiotemporal transition types and influence mechanisms in counties exhibited significant differences, with the coexistence of low-carbon footprint driving, low-carbon footprint restriction, high-carbon footprint driving and high-carbon footprint restriction modes. As the influence mechanisms of different modes and the paths to achieve "dual carbon" goals are different, the governance of different modes should focus on optimizing and strengthening restriction factors or controlling and improving of driving factors.

Glucocorticoid receptor suppresses gene expression of Rev-erbα (Nr1d1) through interaction with the CLOCK complex.

Glucocorticoids have various medical uses but are accompanied by side effects. The glucocorticoid receptor (GR) has been reported to regulate the clock genes, but the underlying mechanisms are incompletely understood. In this study, we focused on the suppressive effect of the GR on the expression of Rev-erbα (Nr1d1), an important component of the clock regulatory circuits. Here we show that the GR suppresses Rev-erbα expression via the formation of a complex with CLOCK and BMAL1, which binds to the E-boxes in the Nr1d1 promoter. In this GR-CLOCK-BMAL1 complex, the GR does not directly bind to DNA, which is referred to as tethering. These findings provide new insights into the role of the GR in the control of circadian rhythm.