Metabolism
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
Abstract
Authors
Camila L. Rossetti, Bruna L. Alves, Ernesto Bernal-Mizrachi, Joao Pedro Werneck-de-Castro
Abstract
Myofibroblasts are the cells responsible for collagen production, leading to tissue fibrosis. Because 20.5% of the total amino acids in collagen are proline, myofibroblasts must acquire a well-developed proline-producing mechanism during their differentiation. However, the detailed mechanism for myofibroblasts to acquire and keep the developed proline biosynthesis machinery remains obscure. Here, we show branched-chain amino acid transaminase 1 (Bcat1) is up-regulated in a substantial subset of Postn-expressing proto-myofibroblast-like fibroblasts, transitional cells en route to fully differentiated myofibroblasts, as well as in myofibroblasts in the fibrotic heart and liver of mice and humans and promotes the proline production. The branched-chain amino acid (BCAA) production by BCAT1 promotes SMAD3 phosphorylation via HDAC5 phosphorylation at Ser488, thereby enhancing SMAD3-dependent transcription of proline biosynthesis-related genes, Aldh18a1, Pycr1, and Eprs, in proto-myofibroblast-like fibroblasts and myofibroblasts. In BCAT1-deficient mice, expression of proline biosynthesis-related genes is significantly attenuated in their hearts after myocardial infarction, resulting in decreased cardiac fibrosis. Moreover, BCAT1 inhibitor treatment of mice with myocardial infarction reduces cardiac fibrosis. Our results identified a BCAT1-mediated pathway that promotes collagen production via proline biosynthesis regulation in proto-myofibroblast-like fibroblasts and myofibroblasts, which may provide a therapeutic target for cardiac fibrosis.
Authors
Noburo Takizawa, Takanori Hironaka, Hayato Watanabe, Haruna Suetsugu, Keisuke Yoshioka, Yuma Horii, Yuri Nagata, Hiroaki Matoba, Hidetaka Kosako, Kenji Hamase, Go Hirai, Michio Nakaya
Abstract
Regulatory T (Treg) cells in visceral adipose tissue (VAT) play essential roles in systemic metabolic homeostasis under distinct physiological and pathological conditions. However, the metabolic cues that drive Treg cell subset specialization in the obese VAT niche remain elusive. Here, we demonstrated that palmitic acid instigated chronic VAT inflammation and systemic metabolic disturbance by compromising the immunosuppressive function of the ICOShi Treg subset. Palmitic acid, but not oleic acid, activated Crebzf expression in VAT Treg cells from HFHS diet-induced obese and ob/ob mice. Crebzf deficiency significantly attenuated diet-induced obesity and inflammation by upregulating the suppressive function of VAT ICOShi Treg cells. Moreover, adoptive transfer of Crebzf-deficient ICOShi Treg cells into Rag1-/- mice alleviated HFHS diet-induced inflammation and metabolic disorders more effectively than transfer of Crebzf-sufficient ICOShi Treg cells. Mechanistically, CREBZF interacted with c-JUN to inhibit Foxp3 activity, thereby impairing the stability and inhibitory cytokine production of ICOShi Treg cells. In human subjects, CREBZF levels in VAT Treg cells were elevated and negatively correlated with FOXP3 activity. Collectively, these findings uncover a specific ICOShi Treg subset that responds to palmitic acid, thereby coupling obesogenic signals to VAT remodeling and systemic metabolic homeostasis.
Authors
Weitong Su, Yuxiao Liu, Xi Yan, Mengyao Huang, Linghao Xu, Jing Lin, Xufeng Chen, Puyuan Hu, Chenlin Gao, Jian Wen, Hongdong Wang, Dong Ding, Zengpeng Zheng, Wenjing Li, Lianjia Li, Zhan Liu, Keyu Qian, Jing Gao, Tingting Zhang, Xiaobing Mao, Haibing Zhang, Wei Lu, Bin Li, Hong Li, Aoyuan Cui, Yan Bi, Chunxiang Zhang, Yu Li
Abstract
Regulatory T cells (Tregs) maintain immune tolerance through mechanisms tightly coupled to cellular metabolism. Whereas glycolysis supports Treg migration, lipid metabolism sustains their suppressive phenotype. Here, we identify the sterol regulatory element–binding protein 1c (SREBP1c) as a central regulator of Treg immunobiology. Tregs from Srebp1c-deficient mice displayed impaired suppressive function, reduced frequencies in circulation and lymphoid tissues, and diminished expression of functional markers. These defects stemmed from intrinsic metabolic rewiring rather than systemic alterations, as both ex vivo Tregs (CD4+CD25hiFoxP3+) and in vitro-derived Tregs lacking Srebp1c were shifted toward glycolysis. Integrated transcriptomic and lipidomic analyses revealed that Srebp1c-deficient Tregs exhibited defective phospholipid remodeling, with an accumulation of lysophosphatidylcholines over phosphatidylcholines, which we attributed to enhanced cytosolic phospholipase A2 (cPLA2α) activity and disruption of the Lands cycle. Altered lipid composition impaired adenosine-mediated immunosuppression by reducing CD73 expression and extracellular adenosine generation. Accordingly, pharmacological inhibition of cPLA2α restored adenosine signaling, CD73 expression, and Treg suppressive capacity. Thus, by preserving phospholipid homeostasis, SREBP1c functions as an immunometabolic checkpoint that links lipid metabolism to adenosine-dependent Treg suppression.
Authors
Fabrizia Bonacina, Claudio Procaccini, Marta Iaia, Arianna Moretti, Monika Svecla, Silvia Pedretti, Jeroen F.J. Bogie, Giovani Battista Vingiani, Annalisa Moregola, Francesca Genova, Claudia Russo, Giusy De Rosa, Claudia La Rocca, Giada Mondanelli, Marco Gargaro, Nico Mitro, Giuseppe Matarese, Giuseppe Danilo Norata
Abstract
Antimetabolites, chemotherapy targeting nucleotide biosynthesis, are among the oldest and most widely used cancer treatments, yet resistance remains a daunting barrier, especially in the fight against B cell lymphomas. However, the underlying mechanisms of this resistance have long remained elusive. Using an innovative, integrated omics approach, we unexpectedly identified that the accumulation of dipeptides and upregulation of the dipeptide transporter SLC15A3 underlie resistance to nucleotide deficiency in a Myc-driven large B cell lymphoma mouse model. A similar mechanism occurred after long treatment of human B cell lymphoma cells with the chemotherapeutic purine synthesis inhibitor 6-mercaptopurine (6MP). Mechanistically, we demonstrated that dipeptides containing essential amino acids activated the growth and survival mTOR complex 1 (mTORC1) signaling pathway. Notably, SLC15A3 specifically interacted with mTOR on the lysosome, boosting mTORC1 activity selectively in resistant lymphoma cells but not in parental cancer cells. Silencing SLC15A3 diminished mTORC1 activity and restored resistant lymphoma sensitivity to 6MP. Strikingly, resistant lymphomas, but not primary tumors, exhibited heightened sensitivity to the clinical mTOR inhibitor, rapamycin, in culture and in vivo. We extended these findings in human lymphoma biopsies, which revealed increased SLC15A3 expression following antimetabolite therapy. Together, our study uncovered a metabolic adaptation that fuels cancer resistance to nucleotide deficiency and positions the mTORC1 inhibitor, rapamycin, as a potential therapeutic strategy for transforming the management of chemotherapy-resistant lymphomas.
Authors
Haojun Yang, Vincenzo Andrea Zingaro, Kevin Boardman, Ashish Noronha, Ekin Guney, Lingru Xue, Saishma Hoigebazar, Isabelle Liu, Sohit Miglani, Siyu Chen, Hieu Vu, Kwun Wah Wen, Hao G. Nguyen, Hani Goodarzi, Ralph J. DeBerardinis, Davide Ruggero
Abstract
BACKGROUND Obesity and weight loss in adults have been associated with distinct metabolome and gut microbiome features, but the extent to which those associations apply to adolescent stages remain unclear.METHODS The Pediatric Obesity Microbiome and Metabolism Study (POMMS) enrolled 220 adolescents aged 10–18 with severe obesity (OB) and 67 individuals who were healthy weight controls (HWCs). Blood, stool, and clinical measures were collected at baseline and after a 6-month obesity intervention for the OB group. Metabolomic profiling in serum using targeted quantitative mass spectrometry and microbiome profiling in stool were performed, and those features were assessed for associations with BMI, insulin resistance, and inflammation. Fecal microbiome transplants (FMT) were performed on germ-free mice using samples from both groups to assess effects on weight gain and metabolic pathways.RESULTS Adolescents with OB exhibited higher serum branched-chain amino acid (BCAA) but lower branched-chain ketoacid (BCKA) levels compared with HWC. This pattern was sex- and age-dependent and differed from adults with obesity who show elevated levels of both BCAA and BCKA. Longitudinal analysis identified metabolic and microbial features correlated with changes in health measures during the intervention. The fecal microbiomes of adolescents with OB and HWC had similar diversity but differed in membership and functional potential. FMT from both OB and HWC donors had similar effects on mouse body weight, but specific taxa were linked to weight gain in recipients of FMT.CONCLUSION Adolescents with OB have unique metabolomic adaptations and microbiome signatures compared with their HWC counterparts and adults with OB.TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT03139877 (Observational Study) and NCT02959034 (Repository).FUNDING SUPPORT American Heart Association Grants: 17SFRN33670990, 20PRE35180195; National Institute of Diabetes and Digestive and Kidney Diseases Grant: R24-DK110492.
Authors
Jessica R. McCann, Chengxin Yang, Nathan A. Bihlmeyer, Runshi Tang, Tracy Truong, Wei Zhou, Jie An, Jayanth Jawahar, Olga Ilkayeva, Michael J. Muehlbauer, Zhengzheng Hu, Holly Kloos Dressman, Lisa Poppe, Joshua A. Granek, Jason W. Arnold, Lawrence A. David, Julia Oh, Pixu Shi, Pinar Gumus Balikcioglu, Svati H. Shah, Sarah C. Armstrong, Christopher B. Newgard, Patrick C. Seed, John F. Rawls
Abstract
Cholesterol overload contributes to metabolic dysfunction–associated steatohepatitis (MASH) progression. One major pathway that limits hepatic cholesterol accumulation is export via VLDL secretion. While sterol regulatory element–binding protein (SREBP) activity is suppressed by insulin-induced gene 1 (INSIG1) under high sterol conditions, VLDL secretion nonetheless persists to prevent lipotoxicity and liver injury, presenting an unresolved paradox in cholesterol sensing and lipoprotein export. Here, we identified a cholesterol-responsive interaction between nuclear factor erythroid 2 related factor-1 (NFE2L1) and INSIG1 that preserved cholesterol homeostasis by sustaining VLDL secretion. Liver-specific NFE2L1 deletion elevated INSIG1 abundance, suppressed SREBP1 activation, and impaired VLDL secretion, leading to hepatic cholesterol accumulation and liver injury. Mechanistically, NFE2L1 bound to INSIG1 via its N-terminal homology box 2 (NHB2) domain; free cholesterol strengthened this interaction to promote INSIG1 degradation, thereby enabling SREBP1 activation and VLDL export. In NFE2L1-deficient mice, WT NFE2L1, but not a mutant NFE2L1 form unable to interact with INSIG1 (NHB2-deleted mutant, ΔNHB2), restored SREBP1 activity and VLDL secretion. Lipidomics analysis revealed that NFE2L1 deficiency reduced serum triglyceride composition, which was restored exclusively by WT NFE2L1. In a murine MASH model, NFE2L1 overexpression activated SREBP1/2, lowered hepatic cholesterol, and attenuated liver injury, inflammation, and fibrosis, without elevating atherogenic lipoproteins owing to compensatory LDL receptor upregulation. Together, these findings explain how VLDL secretion capacity was maintained under cholesterol excess and identify the NFE2L1/INSIG1 axis as a sterol-responsive safeguard for hepatic lipid homeostasis and a potential therapeutic target for MASH.
Authors
Shijun Deng, Jessica E. Freed, Grace Y. Lee, Gizel Askin, Zhe Cao, Özgür Cakici, Bo Yuan, Sheng Tony Hui, Karen E. Inouye, Isabel Graupera, Gökhan S. Hotamışlıgil
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)