Metabolism
Abstract
Metabolic-associated steatohepatitis (MASH) involves hepatocyte damage that cannot be explained solely by lipid accumulation. Here, to discover injury-specific pathways, we focused on a gene of uncertain function, EF-Hand Domain Family Member D1 (EFHD1), identified in human genome-wide association studies of liver injury but not liver fat. We show that EFHD1, a Ca2+-dependent actin crosslinker, stabilizes endoplasmic reticulum–mitochondria contact sites (ERMCS), detecting spatiotemporal coincidence of inter-organellar proximity and ER Ca2+ release. During MASH, EFHD1 upregulation drives pathological mitochondrial fragmentation via excessive contact persistence. This structural failure promotes mitochondrial double-stranded RNA escape and activation of a maladaptive antiviral PKR-associated stress response, a causal relationship also supported by Mendelian randomization in humans. Consequently, inhibiting EFHD1 in human and mouse models blunts hepatocyte damage. These findings identify EFHD1 as a Ca2+-dependent ERMCS stabilizer, reveal a hepatocyte-intrinsic injury pathway, and suggest EFHD1 inhibition as a therapeutic strategy.
Authors
David R. Eberhardt, Emma C. Rekate, Yasmin B. Masini, Hannah E. Duron, David Mollinedo, Adrian M. Velarde, Devorah Stucki, Tara R. Price, Sandra H.J. Lee, Enrique Balderas, Neeraj K. Rai, Ashley R. Bratt, Anthony M. Balynas, Chris J. Stubben, Ryan Bia, Sudipa Maity, Nicolas Hartel, Xue Yin, Andrea Corbin, Anshu Kumari, Dung M. Nguyen, Daisuke Shimura, Vu D. Nguyen, Vishaka Vinod, Kamrul H. Chowdhury, Francisco Verdeguer, Joel Zvick, Patrice N. Mimche, Sihem Boudina, Stavros G. Drakos, Ademuyiwa S. Aromolaran, Sarah Franklin, Vivek Garg, Robin M. Shaw, William L. Holland, Scott A. Summers, Marcus G. Pezzolesi, Jared Rutter, Kimberley J. Evason, Dipayan Chaudhuri
Abstract
Authors
Rong Tian, E. Douglas Lewandowski
Abstract
Authors
Chai-Wan Kim, Matthew A. Mitsche, Jay D. Horton
Abstract
Insulin resistance (IR) has emerged as a risk factor for lactation insufficiency and delays the onset of milk secretion after childbirth, termed secretory activation (SA). This may cause inadequate infant weight gain and early breastfeeding cessation. However, the mechanisms underlying delayed SA in insulin resistant women are unknown. To investigate this, we characterized the mammary transcriptomes and IR-related hormones of 75 breastfeeding women with healthy term infants during postpartum days 1-5. Participants were divided into IR tertiles based on plasma leptin-to-adiponectin ratio measurements. Those in the highest tertile had later SA onset with greater neonatal weight loss during postpartum days 1-5. Transcriptomic analysis on postpartum day 2 (n=4 high IR vs. n=8 low IR participants) showed transient suppression of mammary insulin and prolactin signaling genes, increased pro-inflammatory gene expression and altered expression of >200 mammary mitochondrial genes. These alterations were absent on postpartum days 3-5. Cultured mammary epithelial cells (MECs) treated with insulin showed upregulation of prolactin signaling and oxidative phosphorylation (OXPHOS) genes, with imaging and bioenergetic studies demonstrating that insulin promotes mitochondrial biogenesis and OXPHOS. Thus, our findings delineate roles for insulin in mammary bioenergetics and highlight mitochondrial dysfunction as a mechanism for delayed SA in insulin resistant women.
Authors
Xin Meng, Taha Elajnaf, Hussam Rostom, Michelle Ma, Annalee Furst, Bryony R. Davies, Isabella R. Honess, Gaurav Pandey, Isadora C. Furigo, Craig L. Doig, Jayne F. Martin Carli, Rajesh V. Thakker, Lars Bode, Kelsey E. Johnson, Fadil M. Hannan
Abstract
Liver sinusoidal endothelial cells (LSECs) regulate nutrient flux and immune surveillance within the hepatic niche, yet how they function as metabolic stress sensors that instruct adaptive immune remodeling during metabolic dysfunction-associated steatotic liver disease (MASLD) remains unclear. Here, single-nucleus transcriptomics of human MASLD reveals stage-dependent activation of the cyclic GMP-AMP synthase (cGAS)–stimulator of interferon genes (STING) signaling in LSEC comparable to that in macrophage, with endothelial activation showing greater responsiveness to metabolic stress. Endothelial-specific STING deletion attenuates steatohepatitis and fibrosis in mice. Mechanistically, LSEC-intrinsic STING activation reprograms the angiocrine landscape through NF-κB-mediated transcriptional repression of the endothelial-derived factor BMP4. Loss of BMP4 disrupts the tolerance-supporting sinusoidal immunometabolic niche, skewing CD4⁺ T cell differentiation toward pathogenic Th17 states while destabilizing Treg, collectively exacerbating hepatic metabolic failure. In human MASLD, endothelial STING activity inversely correlates with BMP4 expression at single-cell resolution. Targeted delivery of a STING inhibitor to LSECs using peptide-functionalized nanoparticles restores hepatic metabolic-immune balance at one-tenth the systemic dose. Together, these findings establish endothelial STING as a metabolically responsive vascular immune checkpoint that links chronic metabolic stress to adaptive immune remodeling and fibrotic progression.
Authors
Zhi-Bin Lin, Peng Zou, Xian-Yi Ma, Jun-Bo Song, Hong Zhang, Wei Du, Dan Wei, Ping Song, Xin Hong, Jingjing Liu, Zhi-Qiang Fang, Hao Xu, Fei He, Juan-Li Duan, Ke-Feng Dou, Lin Wang
Abstract
Metabolic dysfunction-associated steatotic liver disease (MASLD) has emerged as a global health concern. Nevertheless, its underlying pathological mechanisms remain poorly understood. Here, we showed that E3 ubiquitin ligase ring finger protein 10 (RNF10) protein levels were positively correlated with MASLD in both mice and humans. Hepatic-specific Rnf10 deletion attenuated liver steatosis, inflammation, and fibrosis. Conversely, adeno-associated virus (AAV)-mediated hepatic-specific Rnf10 overexpression exacerbated MASLD-related phenotypes. Mechanistically, RNF10 interacted with carnitine palmitoyltransferase 1A (CPT1A) and facilitated its degradation through K48-linked ubiquitination, thereby inhibiting fatty acid oxidation, promoting hepatic lipid accumulation, and ultimately exacerbating liver inflammation and fibrosis. Moreover, we utilized triantennary N-acetylgalactosamine (GalNAc) to deliver small interfering RNA (siRNA) specifically targeting Rnf10 to hepatocytes. This approach effectively ameliorated diet-induced liver steatosis, inflammation, and fibrosis in mice. Therefore, interfering with the expression or function of RNF10 may be a promising therapeutic strategy for MASLD.
Authors
Chunyuan Du, Yinliang Zhang, Hongkai Chang, Chaofan Xu, Sufang Sheng, Ke Xu, Wei Qiao, Yanjun Liu, Tongtong Zhang, Yong Gao, Peng Li, Yongsheng Chang
Abstract
Intestinal lipid metabolism is essential for systemic energy homeostasis, and its modulation is emerging as a therapeutic strategy for obesity. Menin, a scaffold protein that regulates chromatin remodeling and gene expression, is abundantly expressed in intestinal epithelial cells (IECs), but its metabolic role remains underexplored. Here, we generated IEC-specific Men1 knockout mouse and found that Men1 deficiency protected against high-fat diet-induced obesity, accompanied by elevated carboxylesterase 1 (CES1) expression in IECs. Increased CES1 promoted triglyceride (TG) hydrolysis and reduced intracellular TG storage, thereby limiting the lipid substrate pool required for ApoB48-dependent chylomicron assembly. Although lipid hydrolysis was enhanced, steady-state free fatty acid levels were not increased; instead, Men1 deficiency activated fatty acid β-oxidation programs and increased etomoxir-sensitive fatty acid–dependent mitochondrial respiration, supporting enhanced fatty acid catabolism. Mechanistically, menin recruited histone deacetylase 1 and interacted with the nuclear receptor LXRβ to suppress Ces1g transcription, thereby sustaining efficient intestinal lipid absorption. Pharmacological inhibition of menin with MI-463 recapitulated the metabolic effects of inducible Men1 deletion. In a human gut organoid-on-chip system, MI-463 dose-dependently increased CES1 expression and markedly reduced lipid accumulation. Collectively, our findings identify menin as a regulator of intestinal lipid metabolism and suggest menin inhibition as a potential therapeutic strategy for obesity-related metabolic disorders.
Authors
Xiaoru Cao, Pingping Zhou, Haiyue Meng, Zhitao Guo, Yan Cao, Chenghao Wang, Lulu Liu, Yinghao Guo, Yue Wang, Guoshun Xin, Dabin Liu, Feng Geng, Jian Ma
Abstract
Polyendocrine metabolic ovarian syndrome (PMOS), formerly known as polycystic ovary syndrome (PCOS), is the most common endocrine disorder in women and is closely associated with complex diseases such as cardiovascular disease and type 2 diabetes. However, the mechanistic links between PMOS and its comorbidities remain poorly understood. Here, we present an integrative systems genetics platform that leverages genetic diversity in both mice and humans to dissect the drivers of PMOS and its associated complications. This framework uncovers conserved genetic and environmental factors underlying PMOS, identifies susceptible cell types and organs, and elucidates mechanisms linking PMOS to subsequent pathologies. For instance, we show that increased ovarian area contributes to both PMOS susceptibility and ovarian cancer progression, while specific ovary–heart signaling circuits modulate cardiac function with aging. We further identify ovarian SF3B1-mediated alternative splicing as a key mechanistic link between PMOS and metabolic traits. Pharmacologic inhibition of SF3B1 in mice reduced circulating testosterone, insulin and glucose levels, as well as fat mass expansion. Transcriptomics analysis of ovaries from mice and experiments using human cell lines localized these effects to exon skipping events in granulosa cells. Together, this study offers a mechanistic framework for modeling the diversity of PMOS pathologies and uncovers SF3B1-mediated splicing as a link between ovary function and systemic metabolism.
Authors
Christy M. Nguyen, Leandro M. Velez, Youngseo Cheon, Cimone L. Jackson, Casey D. Johnson, Ian Tamburini, Mingqi Zhou, Erik Alvstad, Isoo Yoon, Farheen Dustagheer, Marie Li, Tvisha Gujjarlapudi, Kaitlene Ofilan, Neha Mishra, Evan G. Williams, Danica Kwan, Carlos H. Viesi, Naveena Ujagar, David G. Ashbrook, Alistair Senior, Marin E. Nelson, Nicholas R. Pannunzio, Selma Masri, Evgeny Kvon, Grant MacGregor, Cholsoon Jang, Vittorio Sebastiano, Minji Byun, Changrui Xiao, Alexander S. Kauffman, Robert W. Williams, David E. James, Ivan Marazzi, Dequina Nicholas, Marcus Seldin
Abstract
Loss-of-function mutations in PSMB8/beta5i and other components of the 20S proteasome result in multi-organ diseases, such as Chronic atypical neutrophilic dermatosis with lipodystrophy and elevated temperature (CANDLE) syndrome. Neurocognitive dysfunction associated with CANDLE suggests that proteasomal mutations may impact neuronal function and development early in life. We generated cerebral organoids (COs) from induced pluripotent stem cells (iPSCs) made from CANDLE patients. The COs from CANDLE iPSCs exhibited impaired neuronal development when compared to COs from healthy control iPSCs. Impaired neuronal maturation in CANDLE COs was correlated with increased polyamines, which were also elevated in CANDLE patient CSF. The proteasome-regulated Ornithine decarboxylase (ODC), the rate limiting enzyme in polyamine biosynthesis, was elevated in CANDLE neurons. Inhibition of ODC reversed polyamine overproduction and repaired neuronal maturation in CANDLE COs, suggesting a potential therapeutic avenue for intervention. These findings demonstrate that dysfunction of the proteasome affects neuronal development through overproduction of polyamines via dysregulation of ODC and offer insight into potential therapeutic strategies for CNS-related proteasomal dysfunction.
Authors
Clayton W. Winkler, Benjamin Schwarz, Katie Williams, Sara Alehashemi, Simote T. Foliaki, Joseph Snow, Lisa Joseph, Audrey Thurm, Christopher L. Friend, Gwendolyn Cooper, Eric Bohrnsen, Farzana Bhuyan, Nathan T. Brandes, Ruin Moaddel, Manfred Boehm, Guibin Chen, Cole D. Kimzey, Bibiana Bielekova, Joanna Kocot, Peter Kosa, Cathryn L. Haigh, Raphaela Goldbach-Mansky, Karin E. Peterson
Abstract
Endoplasmic reticulum (ER) stress contributes to β cell death in both Type 1 and Type 2 diabetes (T1D and T2D). However, the molecular mechanisms driving β cell death during ER stress remain insufficiently defined, limiting development of protective therapies. GRP78, an ER chaperone, is the master regulator of unfolded protein response (UPR), suppressing UPR initiators during the unstressed state and releasing them to allow UPR activation during stress. To dissect the pathways leading to ER-stress response related β cell decompensation, we engineered mice genetically lacking GRP78 in pancreatic β cells. GRP78 deletion caused acute insulin-deficient diabetes in pups before weaning, with reduced β cell mass due to increased apoptosis. Molecular studies identified deregulated UPR, specifically IRE1 activity, as driving cell death. Unbiased and targeted analyses identified a JNK-p53 axis downstream of IRE1 kinase as a key mediator of β cell death during UPR activation. In vivo JNK inhibition protected against β cell death in 2 distinct ER stress diabetes models. In human β cells, pharmacological inhibition of both JNK and p53 improved β cell survival during GRP78 knockdown–induced UPR. These findings provide insight into mechanisms causing β cell death during ER stress and outline possible therapeutic targets to preserve insulin secretory capacity in diabetes.
Authors
Rohit B. Sharma, Christine Darko, Ying Wang, Thalia A. Castro, Tara Doma Lama, Brian Gablaski, Andrew Rappa, David Redmond, Jason K. Kim, Amy S. Lee, Laura C. Alonso
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)