Kodani, S. D. | bioRxiv Science

bioRxiv2025

Single-Nucleus Analysis of Human White Adipose Tissue Reveals Adipocyte Subsets with Distinct Metabolic Profiles

Anatomic location of white adipose tissue is a determinant of cardiometabolic risk. To understand differences within/between adipose depots, we generated 65,668 single-nucleus transcriptomes from human subcutaneous or intraabdominal adipose tissue (SAT/IAT). Unsupervised analysis revealed 26 adipose-resident cell clusters including two subpopulations of mature adipocytes, characterized by high vs. low expression of adipocyte maturation genes (ADIPOMAThi vs. ADIPOMATlo). ADIPOMATlo adipocytes demonstrate a low-differentiation, pro-inflammatory, and pro-fibrotic transcriptome. IAT-resident ADIPOMATlo were more abundant in higher BMI donors, while SAT-resident ADIPOMATlo associated with impaired glycemia. TSHZ3 was identified as a candidate regulator of ADIPOMATlo transcriptome. TSHZ3 knockdown in adipogenic progenitors inhibited differentiation, with downregulation of early adipogenic regulators (e.g. CEBPA/B, PPARG) and mature adipocyte genes. Heterozygous deletion of Tshz3 in mice reduced SAT and IAT weight. Here, we show that adipocyte subsets with distinct transcriptomic signature reside in human WAT; altered TSHZ3-mediated transcriptional regulation may contribute to low-maturation subpopulation linked to metabolic disease.

cell biology↗

bioRxiv2025

Mitochondrial ATP-Sensitive K+ Channels (MitoKATP) Regulate Brown Adipocyte Differentiation and Metabolism

Brown adipose tissue (BAT) plays a central role in mammalian non-shivering thermogenesis, dissipating mitochondrial membrane potentials through the activity of uncoupling protein UCP1 to release heat. Inner membranes of mitochondria are known to be permeable to potassium ions (K+), which enter the matrix either through ATP-sensitive channels (MitoKATP) or leakage across the bilayer driven by inner membrane potentials. Mitochondrial K+ influx is associated with increased osmotic pressure, promoting water influx and increasing matrix volume. Since BAT mitochondria have lower inner membrane potentials due to uncoupling protein 1 (UCP1) activity, we hypothesized this could involve compensatory changes in MitoKATP activity, and thus tested MitoKATP involvement in brown adipocyte activities under basal and stimulated conditions. We find that cold exposure and adrenergic stimulation in mice modulate BAT MitoK levels, the channel portion of MitoKATP. Genetic ablation of the gene that codes for the pore-forming subunit of MitoKATP in human pre-adipocytes decreased cellular respiration and proliferation, compromising differentiation into mature adipocytes. In mouse cell lines, the absence of the protein limited cellular oxygen consumption in the precursor stage, but not in mature adipocytes. Interestingly, inhibition of MitoKATP in mature adipocytes increased adrenergic-stimulated oxygen consumption, indicating that shutdown of this pathway is important for full BAT thermogenesis. Similarly, MitoKATP inhibition increased oxygen consumption in BAT mitochondria isolated from mice treated with beta 3 adrenergic receptor agonist CL316,243. Overall, our results suggest that the activity of MitoKATP regulates differentiation and metabolism of brown adipocytes, impacting on thermogenesis. New and NoteworthyBrown fat cells are important to maintain healthy body weight by promoting mitochondrial uncoupling. Here, we demonstrate that mitochondrial ATP-sensitive potassium channels (MitoKATP) have important roles both in the differentiation of brown fat cells and in the activation of energy-dissipating uncoupling in this tissue.

physiology↗