Endocrinology
Abstract
Acquired generalized lipodystrophy (AGL) is a rare metabolic disorder frequently associated with autoimmunity. Its etiology is incompletely understood, and the effect of adipose tissue loss on intestinal inflammation in AGL remains unclear. Using mass cytometry and single-cell RNA-seq, we observed an oligoclonal expansion of T cells in the periphery and inflamed intestine in a patient with AGL and Crohn’s disease (AGLCD). To explore if loss of adipose tissue triggers lymphoproliferation, we studied lipodystrophic mice as a model for AGL. Unexpectedly, lipodystrophic mice did not show T cell expansion, were protected from colitis, and displayed a defect in the development of proinflammatory T cells, which could be reversed by allogeneic fat transplantations, indicating that clonal T cell expansion in AGLCD is not primarily caused by lipodystrophy. Instead, gene sequencing revealed a T cell–intrinsic de novo neuroblastoma RAS viral oncogene homolog (NRAS) mutation, implicating somatic mosaicism as a facilitator of clonal T cell expansion and intestinal inflammation in AGLCD.
Authors
Marilena Letizia, Toka Omar, Patrick Weidner, Manuel O. Jakob, Inka Freise, Susanne M. Krug, Britt-Sabina Löscher, Elisa Rosati, Benedikt Obermayer, Reyes Gamez-Belmonte, Julia Hecker, Jörn-Felix Ziegler, Benjamin Weixler, Patrick Asbach, Desiree Kunkel, Michael Stumvoll, Konstanze Miehle, Christoph Becker, Christoph S.N. Klose, Rainer Glauben, Dieter Beule, Anja A. Kühl, Thomas Conrad, Frank Tacke, Stefan Wirtz, Andre Franke, Ashley D. Sanders, Britta Siegmund, Carl Weidinger
Abstract
BACKGROUND Gut microbes and their metabolites contribute to the host circulating metabolome and exhibit diurnal variation influenced by sleep-wake cycles and meal timing. Sleep deprivation alters the rhythmic circulating metabolome, but its impact on microbial metabolites remains unclear. We tested whether 24-hour circulating metabolite profiles, including those of microbial origin, differ under normal (habitual) versus short-term restricted sleep.METHODS In a randomized crossover design, 9 healthy adults completed 2 in-lab 24-hour blood sampling sessions (q120): one following 3 nights of normal sleep (8.5 hours/night), the other following 3 nights of sleep restriction (4.5 hours/night). Meal timing and caloric intake were held constant. Serum metabolites were characterized using untargeted reverse-phase liquid chromatography–mass spectrometry and rhythmicity was assessed using empirical JTK_CYCLE analysis.RESULTS We identified 90 metabolites, including 14 of microbial origin or derived from host metabolism of microbial products, e.g., butyrate and tryptophan derivatives. Sleep restriction significantly altered serum metabolite composition compared with normal sleep. While many compounds maintained rhythmicity across conditions, sleep restriction disrupted rhythms of several key compounds, including microbe-derived metabolites. Notably, butyrate and indole-3–propionic acid lost rhythmicity, whereas new rhythms emerged in the tryptophan catabolite, kynurenine, and lipid metabolism intermediates.CONCLUSION We provide evidence that microbial metabolites are detectable in human blood and exhibit sleep-dependent rhythmicity. Sleep restriction alters diurnal circulating microbial and host-derived metabolite rhythms even under constant meal timing, composition, and calories. These findings support links between host sleep patterns and gut microbial metabolism and suggest microbial metabolites as potential biomarkers or mediators of sleep loss–associated health risks.TRIAL REGISTRATION NCT00989976.FUNDING NIH/NCRR KL2RR025000; R56DK102872-01A1, P30DK020595; P30DK042086; K01DK111785; F31DK122714; DOD W81XWH-07-2-0071.
Authors
Vanessa A. Leone, Katya Frazier, Manpreet Kaur, Evan A. Chrisler, Ashley M. Sidebottom, Ethan Tai, ViLinh Tran, Shuzhao Li, Eugene B. Chang, Dean P. Jones, Eve Van Cauter, Erin C. Hanlon
Abstract
Stem cells are critical for the homeostasis of adult tissues. Thyroid hormone (TH), whose intracellular concentration is increased by type 2 deiodinase (D2), is involved in many functions, but its role in quiescence is unknown. Here we show that D2 marks quiescent stem cells in muscle and skin. Genetic D2-depletion in quiescent muscle stem cells triggers their transition from G0 to a GAlert–like state. This increases the proliferative potential of the stem cells, but impairs their self-renewal capacity, leading to depletion of the stem cell pool and regenerative failure over time. Mechanistically, TH sustains Notch signaling, and active Notch overexpression partially rescues D2-depletion. Transient pharmacological inhibition of D2 accelerates muscle regeneration and skin wound healing by promoting stem cell expansion. In conclusion, we show that D2 is a critical metabolic enzyme in maintaining stem cell quiescence and in regulating self-renewal.
Authors
Maria Angela De Stefano, Raffaele Ambrosio, Cristina Luongo, Tommaso Porcelli, Daniela Di Girolamo, Caterina Miro, Monica Dentice, Caterina Missero, Domenico Salvatore
Abstract
BACKGROUND. Estrogen deficiency and progressive hearing loss (HL) are significant concerns in individuals with Turner syndrome (TS). However, whether childhood estrogen deficiency increases HL risk and whether estrogen replacement therapy (ERT) prevents hearing deterioration are still unclear. METHODS. This prospective cohort study recruited children with TS from a tertiary referral center between 2016 and 2024. All participants received standardized recombinant human growth hormone therapy. Longitudinal monitoring data of hormone levels, metabolic parameters, and annual audiological examinations were recorded. The primary analysis used a multivariate Cox model to estimate the adjusted hazard ratio of hearing loss between estrogen-deficient and estrogen-normal TS patients without prior exogenous estrogen exposure. The secondary analysis compared annual pure tone average (PTA) and its changes between the ERT and non-ERT groups in a substudy. RESULTS. Among 87 prepubertal pediatric TS patients, 48 (55.2%) were estrogen-deficient, 38 HL events occurred over 35-month median follow-up. The estrogen-deficient group had higher HL incidence (27 cases, 56.3%; 20.6/100 person-years [PY]) versus estrogen-normal (11 cases, 28.2%; 8.6/100 PY), with estrogen deficiency independently increasing HL risk (HR = 2.93; 95%CI:1.21–7.12). Notably, estrogen deficiency also independently predicted abnormal DPOAE with an even higher effect size (HR = 3.98, 95% CI: 1.35–11.76). The substudy found that initiating ERT at age of 12 significantly preserve auditory function, with the ERT group showing markedly lower PTA and slower hearing deterioration (–1.24 dB/y vs. 1.13 dB/y right ear; –1.85 dB/y vs. 1.04 dB/y left ear, P = 0.001). CONCLUSION. Childhood estrogen deficiency is a modifiable risk factor. Initiating ERT around early adolescence may help hearing preservation. TRIAL REGISTRATION. ChiCTR2300068063. FUNDING. National Natural Science Foundation of China (82173154 and 82471155), Fundamental Research Funds for the Central Universities, Clinical Research 5010 Program, Sun Yat-sen University: 2024004.
Authors
Yan Huang, Liyang Liang, Yanfang Ye, Lina Zhang, Li Ling, Zhe Meng, Wei Liu, Jia Guo, Zulin Liu, Zhen Zhao, Zhigang Zhang, Yu Si
Abstract
Authors
Fadil M. Hannan, Mark Stevenson, Taha Elajnaf, Hussam Rostom, Kate E. Lines, Michelle Stewart, Sara Wells, Lee Moir, Thomas J. Gardella, Rajesh V. Thakker
Abstract
Recurrent hypoglycaemia in type 1 diabetes (T1D) may culminate in impaired awareness of hypoglycaemia (IAH). While neuroimaging studies identified affected brain regions, more complex perspectives integrating vascular dynamics with endocrine profile are missing. 26 healthy adults, 30 T1D patients with normal hypoglycaemia awareness (NAH), and 25 T1D patients with IAH underwent a hyperinsulinaemic stepped clamp (euglycaemia → hypoglycaemia 50 mg.dL-1) combined with pseudo-continuous arterial spin-labelling MRI. Cerebral blood flow (CBF) and sympathetic vasomotor-range (0.02-0.05 Hz) CBF oscillations were modelled against serially sampled plasma cortisol, epinephrine, norepinephrine and glucagon. In healthy controls, hypoglycaemia evoked robust thalamo-striatal and salience–interoceptive CBF increases (mean Cohen’s d across significant clusters=0.93) and suppression of vasomotor oscillations (d=0.71). T1D retained CBF response but failed to attenuate oscillations (dT1D>controls=0.43). IAH further blunted hypoglycaemia-associated CBF increase, especially in thalamus, striatum and insula (dNAH>IAH=0.51). Hormone-CBF coupling differed quantitatively: cortisol/epinephrine–CBF correlations were positive in controls (r=0.37/0.26), negative in NAH (-0.16/-0.40) and strongly positive in IAH (0.42/0.46). Thus, our findings indicate that T1D disrupts dynamic, sympathetic modulation of CBF, whereas IAH additionally impairs perfusion reserve and shows maladaptive catecholamine-dependent CBF regulation, suggesting a qualitatively distinct neurovascular phenotype.
Authors
Pavel Filip, Antonietta Canna, Heidi Grohn, Amir A. Moheet, Anjali F. Kumar, Xiufeng Li, Yuan Zhang, Lynn E. Eberly, Elizabeth R. Seaquist, Silvia Mangia
Abstract
Aging commonly causes decline of testosterone or estrogen, leading to overaccumulation of fatness in males or females, respectively. Although such phenomenon can be readily explained by estrogen’s direct action on adipocytes in females, accumulative evidence does not support the direct action of testosterone in adipocyte lipid metabolism, suggesting that there is a missing intermediary link. Herein, we propose that glycoprotein hormone β5 (GPHB5) is the intermediary linkage between testosterone and the regulation of adiposity. In clinical samples, blood levels of GPHB5 were correlated negatively with men’s ages, and positively with circulating testosterone. Testosterone directly stimulated the expression of GPHB5 in cultured cells, pharmacological blockade of androgen receptor (AR) functions abrogated such effect. Knockout of AR led to not only development of obesity but also reduction of GPHB5 expression. Genetic ablation of GPHB5 in the males, but not in the females, lowered the browning of white adipose tissue, diminished energy expenditure and caused severe obesity. Importantly, elevated blood testosterone didn’t exert its catabolic actions in GPHB5 null mice, and yet, recombinant GPHB5 protein was able to stimulate energy expenditure and reduce adiposity. Taken together, these results provided the strong proof that GPHB5 is the “missing” intermediary hormone linking testosterone (and aging) and its well-known catabolic effect on adipose tissue.
Authors
Gengmiao Xiao, Aijun Qian, Zhuo Gao, Tingting Dai, Hui Liang, Shuai Wang, Mulan Deng, Yunjing Yan, Xindan Zhang, Xuedi Zhang, Yunping Mu, Jiqiu Wang, Aibo Gao, Huijie Zhang, Fanghong Li, Allan Zijian Zhao
Abstract
How β-Catenin (βCat) mediates tissue hyperplasia is poorly understood. To explore this, we employed the adrenal cortex as a model system given its stereotypical spatial organization and the important role βCat plays in homeostasis and disease. For example, excessive production of aldosterone by the adrenal cortex (primary aldosteronism, PA) constitutes a major cause of cardiovascular morbidity and is associated with βCat gain-of-function (βCat-GOF). Adherens junctions (AJs) connect the actin cytoskeletons of adjacent zona Glomerulosa (zG) cells via a cadherin-βCat-α-Catenin complex and mediate aldosterone production. Whether βCat-GOF drives zG hyperplasia, a key feature of PA, via AJs is unknown. Here, we showed that aldosterone secretagogues (K+, AngII) and βCat-GOF mediated AJ formation via Rho/ROCK/actomyosin signaling. In addition, Rho/ROCK inhibition led to altered zG rosette morphology and decreased aldosterone production. Mice with zG-specific βCat-GOF demonstrated increased AJ formation and zG hyperplasia, which was blunted by Rho/ROCK inhibition and deletion of α-Catenin. βCat also impacted AJ formation independently of its role as a transcription factor. Furthermore, analysis of human aldosterone-producing adenomas revealed high levels of βCat expression were associated with increased membranous expression of K-Cadherin. Together, our findings identified Rho/ROCK signaling and αCat as key mediators of AJ formation and βCat-driven hyperplasia.
Authors
Mesut Berber, Betul Haykir, Nick A. Guagliardo, Vasileios Chortis, Kleiton Silva Borges, Paula Q. Barrett, Felix Beuschlein, Diana L. Carlone, David T. Breault
Abstract
The c-Jun N-terminal kinases (JNKs) regulate diverse physiological processes. Whereas JNK1 and JNK2 are broadly expressed and associated with insulin resistance, inflammation, and stress responses, JNK3 is largely restricted to central nervous system neurons and pancreatic β cells, and its physiological role in β cells remains poorly defined. To investigate its function, we generated mice lacking JNK3 specifically in β cells (βJNK3-KO). These mice displayed glucose intolerance and defective insulin secretion, particularly after oral glucose challenge, indicating impaired incretin responses. Consistently, Exendin-4–stimulated (Ex4-stimulated) insulin secretion was blunted in βJNK3-KO islets, accompanied by reduced GLP-1R expression. Similar findings were observed in human islets treated with a selective JNK3 inhibitor (iJNK3). Downstream of GLP-1R, Ex4-induced CREB phosphorylation was diminished in βJNK3-KO islets, indicating impaired canonical signaling. Moreover, activation of the GLP-1R/CREB/IRS2 pathway, a key regulator of β cell survival, was reduced in βJNK3-KO islets and iJNK3-treated human islets. As a consequence, the protective effects of Ex4 were lost in cytokine-treated βJNK3-KO and human islets, and Ex4-mediated protection was partially attenuated in βJNK3-KO mice exposed to multiple low-dose streptozotocin. These findings identify JNK3 as a regulator of β cell function and survival and suggest that targeting this pathway may enhance incretin-based therapies.
Authors
Ruy A. Louzada, Marel Gonzalez Medina, Valentina Pita-Grisanti, Jessica Bouviere, Amanda F. Neves, Joana Almaça, Myoung Sook Han, Roger J. Davis, Gil Leibowitz, Manuel Blandino-Rosano, Ernesto Bernal-Mizrachi
Abstract
BACKGROUND. Amino acid (AA) concentrations are increased in prediabetes and diabetes. Since AA stimulate glucagon secretion which should then increase hepatic AA catabolism, it has been hypothesized that hepatic resistance (associated with hepatic fat content) to glucagon’s actions on AA metabolism leads to hyperglucagonemia and hyperglycemia. METHODS. To test this hypothesis, we therefore studied lean and obese individuals, the latter group with and without hepatic steatosis as defined by Proton Density Fat Fraction (PDFF) > 5%. After an overnight fast, femoral vein, femoral artery, and hepatic vein catheters were placed. [3-3H] glucose and L-[1-13C,15N]-leucine were used to measure glucose turnover and leucine oxidation respectively. During a hyperglycemic clamp, an amino acid mixture was infused together with insulin and glucagon (1.5 ng/kg/min 0 – 120 min; 3.0 ng/kg/min 120 – 240 min). Tracer-based measurement of hepatic leucine oxidation in response to rising glucagon concentrations and splanchnic balance (measured using arterio-venous differences across the liver), of the other AA were the main outcomes measured. RESULTS. The presence of hepatic steatosis did not alter hepatic glucose metabolism and leucine oxidation in response to insulin and rising concentrations of glucagon. Splanchnic balance of a few amino acids, and related metabolites differed amongst the groups. However, across-group differences of AA splanchnic balance in response to glucagon were unaffected by the presence of hepatic steatosis. CONCLUSION. The action of glucagon on hepatic amino acid metabolism is unaffected by hepatic steatosis in humans. TRIAL REGISTRATION. This study was registered at Clinical Trials.Gov: NCT05500586. FUNDING. This work was funding by the NIH.
Authors
Hannah E. Christie, Sneha Mohan, Aoife M. Egan, Federica Boscolo, Chiara Dalla Man, Scott M. Thompson, Michael Jundt, Chad J. Fleming, James C. Andrews, Kent R. Bailey, Michael D. Jensen, K. Sree Nair, Adrian Vella
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ISSN: 0021-9738 (print), 1558-8238 (online)