CLCF1 inhibits energy expenditure via suppressing brown fat thermogenesis.

Brown adipose tissue (BAT) is the main site of nonshivering thermogenesis which plays an important role in thermogenesis and energy metabolism. However, the regulatory factors that inhibit BAT activity remain largely unknown. Here, cardiotrophin-like cytokine factor 1 (CLCF1) is identified as a negative regulator of thermogenesis in BAT. Adenovirus-mediated overexpression of CLCF1 in BAT greatly impairs the thermogenic capacity of BAT and reduces the metabolic rate. Consistently, BAT-specific ablation of CLCF1 enhances the BAT function and energy expenditure under both thermoneutral and cold conditions. Mechanistically, adenylate cyclase 3 (ADCY3) is identified as a downstream target of CLCF1 to mediate its role in regulating thermogenesis. Furthermore, CLCF1 is identified to negatively regulate the PERK-ATF4 signaling axis to modulate the transcriptional activity of ADCY3, which activates the PKA substrate phosphorylation. Moreover, CLCF1 deletion in BAT protects the mice against diet-induced obesity by promoting BAT activation and further attenuating impaired glucose and lipid metabolism. Therefore, our results reveal the essential role of CLCF1 in regulating BAT thermogenesis and suggest that inhibiting CLCF1 signaling might be a potential therapeutic strategy for improving obesity-related metabolic disorders.

Reduced serum CLCF1 levels in hyperthyroidism patients and T3-treated mice.

Characteristic symptoms of hyperthyroidism include weight loss, heart palpitation, and sweating. Thyroid hormones (TH) can stimulate thermogenesis through central and peripheral mechanisms. Previous studies have shown an association between dysfunction of cardiotrophin-like cytokine factor 1 (CLCF1) and cold-induced sweating syndrome, with recent research also indicating a link between CLCF1 and brown adipose tissue thermogenesis. However, it remains unclear whether CLCF1 and TH have synergistic or antagonistic effects on thermogenesis. This study aims to investigate the influence of thyroid hormone on circulating CLCF1 levels in humans and explore the potential possibilities of thyroid hormone in regulating energy metabolism by modulating Clcf1 in mice. By recruiting hyperthyroid patients and healthy subjects, we observed significantly lower serum CLCF1 levels in hyperthyroid patients compared to healthy subjects, with serum CLCF1 levels independently associated with hyperthyroidism after adjusting for potential confounders. Tissue analysis from mice treated with T3 revealed a decrease in CLCF1 expression in BAT and iWAT of C57BL/6 mice. These findings suggest that TH may play a role in regulating CLCF1 expression in adipose tissue.

Effect of time-restricted eating regimen on weight loss is mediated by gut microbiome.

Time-restricted eating (TRE) is a promising obesity management strategy, but weight-loss efficacy varies among participants, and the underlying mechanism is unclear. The study aimed to investigate the role of gut microbiota in weight-loss response during long-term TRE intervention. We analyzed data from 51 obese adults in a 12-month TRE program, categorizing them into distinct weight loss groups (DG) and moderate weight loss groups (MG) based on their TRE responses. Shotgun metagenomic sequencing analysis revealed a significant increase in species closely associated with weight loss effectiveness and metabolic parameter changes in the DG group. Pathways related to fatty acid biosynthesis, glycogen biosynthesis, and nucleotide metabolism were reduced in the DG group and enhanced in the MG group. Next, we identified nine specific species at baseline that contributed better responses to TRE intervention and significant weight loss. Collectively, gut microbiota contributes to responsiveness heterogeneity in TRE and can predict weight-loss effectiveness.