Activin E activates brown and beige adipocytes and has been controversially implicated as a factor that induces obesity and fatty liver. Here, we sought to address this controversial issue by producing recombinant human activin E to evaluate its effects on HB2 brown adipocytes in vitro. Activin E increased uncoupling protein 1 (Ucp1) and fibroblast growth factor 21 (Fgf21) mRNA expression in the adipocytes. This upregulation was suppressed by SB431542, an inhibitor of activin receptor-like kinase (Alk) TGF-β type I receptors. SB431542 also inhibited the activin E-induced phosphorylation of Smad2/3. A promoter assay using a CAGA-Luc reporter and Alk expression vectors revealed that activin E activated the TGF-β/activin pathway via Alk7. The upregulation of Ucp1 and Fgf21 mRNA might be mediated through Alk7 and Smad2/3 phosphorylation. Activin E is a potential stimulator of energy expenditure by activating brown adipocytes and highlights its potential as a therapeutic target for treating obesity.
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http://dx.doi.org/10.1016/j.mce.2024.112326 | DOI Listing |
FASEB J
January 2025
Department of Radiology, C.J. Gorter MRI Center, Leiden University Medical Center, Leiden, The Netherlands.
Brown adipose tissue (BAT) is a metabolically highly active tissue that dissipates energy stored within its intracellular triglyceride droplets as heat. Others have previously utilized MRI to show that the fat fraction of human supraclavicular BAT (scBAT) decreases upon cold exposure, compared with baseline (i.e.
View Article and Find Full Text PDFNutrients
December 2024
Department of Experimental Medicine, Section of Biochemistry, University of Genova, Viale Benedetto XV 1, 16132 Genova, Italy.
Abscisic acid (ABA) is a hormone with a long evolutionary history, dating back to the earliest living organisms, of which modern (ABA-producing) cyanobacteria are likely descendants, which existed long before the separation of the plant and animal kingdoms, with a conserved role as signals regulating cell responses to environmental challenges. In mammals, along with the anti-inflammatory and neuroprotective function of ABA, nanomolar ABA regulates the metabolic response to glucose availability by stimulating glucose uptake in skeletal muscle and adipose tissue via an insulin-independent mechanism and increasing metabolic energy production and also dissipation in brown and white adipocytes. Chronic ABA intake of micrograms per Kg body weight improves blood glucose, lipids, and morphometric parameters (waist circumference and body mass index) in borderline subjects for prediabetes and metabolic syndrome.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Department of Pharmacology, Physiology and Legal and Forensic Medicine, Faculty of Health and Sport Science, University of Zaragoza, 50009 Zaragoza, Spain.
MicroRNAs play a pivotal role in the regulation of adipose tissue function and have emerged as promising therapeutic candidates for the management of obesity and associated comorbidities. Among them, miR-1 could be a potential biomarker for metabolic diseases and contribute to metabolic homeostasis. However, thorough research is required to fully elucidate the impact of miR-1 on human adipocyte thermogenesis and metabolism.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Institute for Cardiovascular Prevention (IPEK), Faculty of Medicine, Ludwig-Maximilians-Universität München, 81377 Munich, Germany.
MicroRNAs (miRNAs) are short sequences of single-stranded non-coding RNAs that target messenger RNAs, leading to their repression or decay. Interestingly, miRNAs play a role in the cellular response to low oxygen levels, known as hypoxia, which is associated with reactive oxygen species and oxidative stress. However, the physiological implications of hypoxia-induced miRNAs ("hypoxamiRs") remain largely unclear.
View Article and Find Full Text PDFCell Rep
January 2025
Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX, USA. Electronic address:
Hepatic stellate cells (HSCs) are key drivers of local fibrosis. Adiponectin, conventionally thought of as an adipokine, is also expressed in quiescent HSCs. However, the impact of its local expression on the progression of liver fibrosis remains unclear.
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