Efficient fatty acid (FA) re-esterification is essential for lipid homeostasis in adipocytes, yet the mechanisms coordinating Coenzyme A (CoA) availability at the endoplasmic reticulum (ER)-a major site of lipid synthesis-remain unclear. Here, we identify TMEM120A as an ER-resident CoA-binding protein that regulates intracellular FA metabolism. TMEM120A interacts with the ER-localized acyl-CoA synthetase ACSL1 and ACSL3 to promote long-chain acyl-CoA synthesis and channeling into the ER, thereby facilitating FA re-esterification and lipid cycling during lipolysis. By relieving acyl-CoA-mediated feedback inhibition of lipolysis, TMEM120A enhances lipid turnover while protecting against ER stress and lipotoxicity. Adipocyte-specific deletion of Tmem120a in mice impairs lipolysis-induced energy expenditure and exacerbates inflammation and metabolic dysfunction under high-fat diet conditions. These findings establish TMEM120A as a critical regulator of ER CoA handling and lipid flux, revealing a previously unrecognized mechanism that links intracellular CoA dynamics to systemic energy balance and metabolic health.
© 2025. The Author(s).

Adipose tissue remodeling plays a critical role in obesity-induced metabolic dysfunction, but the underlying molecular mechanisms remain incompletely understood. This study investigates the role of miR-10a-5p in adipose tissue inflammation and metabolic dysfunction induced by a high-fat diet (HFD).
Male miR-10a knockout (KO) mice were fed a HFD to induce obesity for up to 16 weeks. RNA sequencing (RNA-seq) analysis was performed to profile mRNA expression and assess the effects of miR-10a-5p KO in gonadal white adipose tissue (gWAT). Additional analyses included immunoblotting, qPCR, histological examination, and validation of the miR-10a-5p target sequence using a dual-luciferase reporter assay.
miR-10a-5p was highly expressed in gWAT but decreased after 8 weeks of HFD feeding. Over the 16-week HFD period, miR-10a KO mice exhibited greater weight gain and reduced energy expenditure compared to wild-type (WT) controls. gWAT of miR-10a KO mice on a HFD showed an increased population of proinflammatory macrophages, elevated inflammation, and increased cell death, characterized by upregulated apoptosis and necrosis markers. This was also associated with increased triglyceride accumulation in liver. Mechanistically, the proapoptotic gene Bcl2l11 was identified as a direct target of miR-10a-5p. Loss of miR-10a-5p led to BIM-mediated adipocyte death and inflammation, contributing to mitochondrial metabolic dysregulation, increased fibrosis marker expression, and the onset of inflammation in adipose tissue.
This study demonstrates the significant role of miR-10a-5p and its downstream target BIM in regulating adipocyte death during diet-induced obesity. This signaling pathway presents a potential therapeutic target for modulating obesity-induced inflammation and cell death in adipose tissue.
Copyright © 2024 The Author(s). Published by Elsevier GmbH.. All rights reserved.

Adipose tissue (AT) adapts to overnutrition in a complex process, wherein specialized immune cells remove and replace dysfunctional and stressed adipocytes with new fat cells. Among immune cells recruited to AT, lipid-associated macrophages (LAMs) have emerged as key players in obesity and in diseases involving lipid stress and inflammation. Here, we show that LAMs selectively express transmembrane 4 L six family member 19 (TM4SF19), a lysosomal protein that represses acidification through its interaction with Vacuolar-ATPase. Inactivation of TM4SF19 elevates lysosomal acidification and accelerates the clearance of dying/dead adipocytes in vitro and in vivo. TM4SF19 deletion reduces the LAM accumulation and increases the proportion of restorative macrophages in AT of male mice fed a high-fat diet. Importantly, male mice lacking TM4SF19 adapt to high-fat feeding through adipocyte hyperplasia, rather than hypertrophy. This adaptation significantly improves local and systemic insulin sensitivity, and energy expenditure, offering a potential avenue to combat obesity-related metabolic dysfunction.
© 2024. The Author(s).

The development of white adipose tissue (WAT) occurs during distinct embryonic and postnatal stages, and it is subsequently maintained throughout life. However, the specific mediators and mechanisms responsible for WAT development during different phases remain unclear. In this study, we investigate the role of the insulin receptor (IR) in regulating adipogenesis and adipocyte function within adipocyte progenitor cells (APCs) during WAT development and homeostasis. We use two in vivo adipose lineage tracking and deletion systems to delete IR either in embryonic APCs or adult APCs, respectively, to explore the specific requirements of IR during WAT development and WAT homeostasis in mice. Our data suggest that IR expression in APCs may not be essential for adult adipocyte differentiation but appears to be crucial for adipose tissue development. We reveal a surprising divergent role of IR in APCs during WAT development and homeostasis.
Copyright © 2023. Published by Elsevier B.V.

Adipose tissue macrophages are critical players in obesity-induced inflammation and metabolic dysfunction. Here, we identify transmembrane 4 L six family member 19 (TM4SF19) as a gene upregulated in adipose tissue macrophages in obese states. We demonstrate that TM4SF19 is a lysosomal membrane protein that inhibits vacuolar H+-ATPase activity by interacting with its subunit ATP6V0B. In vitro gain- and loss-of-function assays in macrophages indicate that TM4SF19 reduces lysosomal acidification and impairs the clearance of dead fat cells. Single-nucleus RNA sequencing analysis indicates that TM4SF19 is specifically expressed in a subpopulation of Trem2  + lipid-associated macrophages, and global knockout reduces diet-induced obesity and recruitment of pro-inflammatory macrophages to adipose tissue. Moreover, global or macrophage-specific TM4SF19 knockout decreases the number of lipid-stressed adipocytes induced by high-fat feeding and restores tissue insulin sensitivity. Overall, these results suggest that TM4SF19-mediated control of lysosomal activity is a potential therapeutic target to resolve obesity-induced adipose tissue inflammation.