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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
Hypomorphic variants in the SEL1L-HRD1 ER-associated degradation (ERAD) complex have been linked to severe neurological syndromes in children, including neurodevelopmental delay, intellectual disability, motor dysfunction, and early death. Despite this association, its physiological importance and underlying mechanisms in neurons remain poorly understood. Here, we show that neuronal SEL1L-HRD1 ERAD is essential for maintaining one-carbon metabolism, motor function, and overall viability. Neuron-specific deletion of Sel1L in mice (Sel1LSynCre) resulted in growth retardation, severe motor impairments, and early mortality by 9 weeks of age—mirroring core clinical features observed in affected patients—despite preserved neuronal numbers and only modest ER stress. Multi-omics analyses, including single-nucleus RNA sequencing and metabolomics, revealed significant dysregulation of one-carbon metabolism in ERAD-deficient brains. This included activation of the serine, folate, and methionine pathways, accompanied by elevated levels of S-adenosylmethionine and related metabolites, likely resulted from induction of the integrated stress response (ISR). Together, these findings uncover a previously unappreciated role for neuronal SEL1L-HRD1 ERAD in coordinating ER protein quality control with metabolic adaptation, providing new insight into the molecular basis of ERAD-related neurodevelopmental disease.
Authors
Mauricio Torres, You Lu, Brent Pederson, Hui Wang, Anna Gretzinger, Liangguang Lin, Jiwon Hwang, Xinxin Chen, Alan C. Rupp, Abigail J. Tomlinson, Andrew J. Scott, Zhen Zhao, Daniel R. Wahl, Martin Myers, Jr, Costas A. Lyssiotis, Ling Qi
Abstract
SLC13A5 citrate transporter disorder is a rare epileptic encephalopathy caused by loss of function pathogenic variants in the SLC13A5 gene. Loss of sodium/citrate cotransporter (NaCT) function causes a severe early life epilepsy resulting in life-long developmental disabilities and increased extracellular citrate. Current antiseizure medications may reduce seizure frequency, yet more targeted treatments are needed to address the epileptic and neurodevelopmental SLC13A5 phenotype. We performed preclinical studies in SLC13A5 deficient mice evaluating phenotype rescue with adeno-associated virus (AAV) vector carrying a functional copy of the human SLC13A5 gene (AAV9/SLC13A5). Cerebrospinal fluid-delivery of AAV9/SLC13A5 decreased extracellular citrate levels, normalized electrophysiologic and sleep architecture abnormalities, and restored resistance to chemically induced seizures and death. Treatment benefits were achieved with administration during early brain development and in young adult mice, indicating therapeutic efficacy across developmental and post-developmental stages. Comparison of delivery routes in young adult KO mice showed that higher brain targeting achieved with intra-cisterna magna delivery resulted in greater treatment benefit as compared to intrathecal lumbar puncture delivery. Together, these results support further development of AAV9/SLC13A5 for treating SLC13A5 citrate transporter disorder.
Authors
Lauren E. Bailey, Raegan M. Adams, Morgan K. Schackmuth, Irvin T. Garza, Krishanna Knight, Sydni K. Holmes, Meghan M. Eller, MinJae Lee, Rachel M. Bailey
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
Skeletal muscle frequently experiences oxygen depletion, especially during exercise, and the alpha subunit of the hypoxia-inducible factors (HIF1α and HIF2α) plays a crucial role in mediating cellular adaptation to low oxygen levels. However, although significant, the absence of an appropriate experimental mouse model leaves the precise roles of HIFα in myofibers unclear. Therefore, this study developed mice with myofiber-specific knockouts of prolyl hydroxylase proteins (PHDs), in which HIFα is stabilized, and inducible myofiber-specific overexpression of stable HIF1α or HIF2α to explore the role of HIFα in myofibers. Using three distinct mouse models, we found that HIF1α increased the number of oxidative fibers but paradoxically impaired exercise performance and mitochondrial function. Comparatively, HIF2α exerted protection mechanisms against glucose intolerance and diet-induced obesity. Notably, HIF2α stabilization in skeletal muscle markedly elevated erythropoietin (EPO) levels in muscle and serum but not in the kidney and liver, suggesting skeletal muscle is a previously unrecognized site of EPO production in the body. Thus, this study demonstrates the distinct roles of HIF1α and HIF2α in skeletal muscle, newly uncovering that the PHD-HIF2α axis produces EPO from myofibers.
Authors
Junhyeong Lee, Merc Emil Matienzo, Sangyi Lim, Edzel Evallo, Yeongsin Kim, Sujin Jang, Keon Kim, Chang Hyeon Choi, Youn Ho Han, Chang-Min Lee, Tae-Il Jeon, Sang-Ik Park, Jun Wu, Dong-il Kim, Min-Jung Park
Abstract
Metabolic-inflammatory crosstalk orchestrates muscle repair. Although pyroptosis typically aggravates sterile injury, we demonstrated that GSDME-dependent pyroptotic signaling associated with recruited myeloid cells paradoxically supported regeneration. GSDME expression was induced in post-surgical human muscle injury and murine damage models. Gsdme deficiency delayed functional recovery and exacerbated injury-induced myosteatosis, a pathological form of intramuscular ectopic fat deposition. Time-series and single-cell RNA-sequencing analyses revealed that GSDME loss shifted the transcriptional program from oxidative metabolism toward lipid storage and adipogenesis. Lipidomics confirmed aberrant accumulation of triacylglycerols and sphingolipids in Gsdme-deficient muscle. Single-cell profiling further identified divergent fibro-adipogenic progenitors (FAPs) states skewed toward adipogenesis, accompanied by impaired expansion of restorative Lyve1⁺Cd163⁺Txnip⁺ tissue-resident macrophages (TRMs)—validated by multiplex flow cytometry. Blocking CCR2-dependent monocyte recruitment produced regenerative defects comparable to those caused by Gsdme deficiency. Myeloid-specific Gsdme reintroduction rescued TRM expansion and function, curbed FAP adipogenic reprogramming, whereas FAP-specific expression proved ineffective. Mechanistically, IL-18 downstream of GSDME-dependent signaling engaged KLF4/JUN signaling in TRMs, sustaining their reparative and lipid-clearing capacity. This GSDME–IL-18–TRMs axis was compromised in aged muscle, yet exogenous IL-18 reversed myosteatosis and accelerated regeneration. Together, these findings suggest that GSDME-dependent pyroptotic signaling can act as a metabolic checkpoint that sustains TRM-driven lipid homeostasis to support muscle regeneration.
Authors
Qi Cao, Jian Liu, Gang Huang, Su-Yuan Wang, Guo-Dong Lu, Yong Huang, Yi-Ting Chen, Zhen Zhang, Jiang-Tao Fu, Si-Jia Sun, Xiaofei Chen, Chunlin Zhuang, Chunquan Sheng, Fu-Ming Shen, Dong-Jie Li, Pei Wang
Abstract
Interstitial lung disease (ILD) is a major cause of morbidity and mortality in systemic sclerosis (SSc); however, the immunopathologic mechanisms driving lung disease in SSc are unclear. T cells have been implicated as a likely driver of lung injury in SSc. Here, we have evaluated T cells in the blood of patients with SSc-ILD and identified a specific population of cytotoxic CD8 T cells that is expanded in SSc-ILD patients. Cytotoxic effector memory CD8 T cells marked by CD57 expression are preferentially expanded in SSc-ILD patients compared to SSc patients without ILD and controls and show prominent clonal expansion. These CD57+ T effector memory (TEM) cells differ from T effector memory cells re-expressing CD45RA (TEMRA) transcriptomically and functionally, with cytotoxic function that is enhanced by CD155 engagement of the costimulatory receptor CD226. We performed immunostaining of lung tissue samples obtained from independent SSc-ILD patients (biopsy or explant) and confirmed the presence of CD57+ TEM. In parallel, we analyzed publicly available lung scRNA-seq datasets from multiple ILD cohorts and identified endothelial cells as a likely source of CD155 to activate CD57+ cytotoxic T cells. Together, the results implicate a CD57+ cytotoxic CD8 T cell population as a potential mediator of lung injury in SSc-ILD.
Authors
Takanori Sasaki, Ye Cao, John M. Sowerby, Kazuhiko Higashioka, Kathryne E. Marks, Mehreen Elahee, Mari Kamiya, Paul F. Dellaripa, Richard I. Ainsworth, Kimberly E. Taylor, Nunzio Bottini, Paul Wolters, Edy Y. Kim, Francesco Boin, Deepak A. Rao
Abstract
Stereotactic arrhythmia radiotherapy (STAR) is emerging as a highly effective treatment for ventricular tachycardia (VT). Growing evidence indicates that STAR favorably reprograms the electrical substrate by speeding conduction and/or prolonging repolarization via modulating ion channel expression, though the mechanisms whereby single-fraction radiation mediates durable changes in gene expression are incompletely understood. Here, we identify dynamic changes in the cardiomyocyte epigenome and transcriptome after irradiation (IR) in vivo and in vitro, including durably increased expression and chromatin accessibility of Scn5a (encoding the alpha subunit of the sodium channel, NaV1.5), demonstrating a role for epigenetic memory in conduction velocity (CV) increases observed after STAR. Transcriptomic and epigenetic sequencing further identify dynamic changes to gene expression and regulatory regions involved in cellular repolarization, calcium handling, and metabolism after IR. These changes are mirrored by dose-dependent and cell-autonomous changes in repolarization, calcium flux, and mitochondrial respiration, highlighting important cellular processes which may mediate therapeutic effects of STAR. Overall, we find that cardiomyocytes exposed to a single fraction of high-dose IR exhibit epigenetic reprogramming that mediates broad and dynamic physiologic responses.
Authors
Samuel D. Jordan, Shuhua Fu, Abigail Fulkerson, Donghua Hu, Sherwin Ng, David M. Zhang, Sneha Manikandan, Jeffrey Szymanski, Nan Hu, Yuqian Xie, Anish Bedi, James J. Tabor, Lauren Boggs-Bailey, Lori Strong, Stephanie Hicks, Lavanya Aryan, Nishanth Gabriel, Geoffrey D. Hugo, Kuo-Chan Weng, Nathaniel Huebsch, Julie K. Schwarz, Bo Zhang, Stacey L. Rentschler
Abstract
Mutations in SLC26A4 are the second most common cause of hereditary hearing loss in many Asian countries, leading to DFNB4, a condition characterized by progressive hearing loss and inner ear malformations. While gene therapy holds great potential, its postnatal application has remained unexplored due to the lack of suitable animal models and the challenges of prenatal intervention. This study represents the first preclinical investigation of postnatal gene therapy for DFNB4 using a clinically relevant Slc26a4 mutant mouse model that closely replicates human auditory phenotypes. Utilizing the synthetic AAV.Anc80L65 vector, we achieved robust SLC26A4 delivery to critical cochlear regions, including the endolymphatic sac and cochlear lateral wall. Comprehensive phenotypic analyses revealed a critical therapeutic window spanning the neonatal and juvenile stages, within which AAV.Anc80L65-mediated SLC26A4 delivery significantly improved hearing, as evidenced by lower auditory brainstem response thresholds. Moreover, the therapy preserved hair cells, reduced endolymphatic sac enlargement, partially restored the endocochlear potential, and mitigated inner ear structural degeneration. These therapeutic effects persisted into adulthood, highlighting the long-term efficacy of postnatal gene therapy. Together, these findings establish a critical therapeutic window for DFNB4 and demonstrate the feasibility of targeting the endolymphatic sac and cochlear lateral wall for effective intervention.
Authors
Yi-Hsiu Tsai, Peng-Yu Wu, Yu-Chi Chuang, Chun-Ying Huang, Hiroki Takeda, Hiroshi Hibino, Chen-Chi Wu, Yen-Fu Cheng
Abstract
The gastrointestinal tract varies in structure and function by region, yet the drivers of region-specific inflammatory disease remain elusive. Here, a TNF-overexpressing murine model (TnfΔARE/+) of Crohn’s disease (CD) was used to investigate how pathobionts interact with host immune susceptibilities to drive region-specific disease. We identified the pathobiont Chlamydia muridarum, an intracellular bacterium and murine counterpart to the human sexually transmitted C. trachomatis, as a necessary and sufficient trigger for disease manifestation in the proximal/ascending colon, a common site of CD. In genetically susceptible hosts, pathobiont-triggered proximal colonic inflammation is driven by goblet cell responses, one of which through tryptophan metabolism via indoleamine 2,3-dioxygenase (IDO1). Our findings translate to human disease, where we demonstrate upregulation of epithelia-derived IDO1 in actively inflamed ascending colon specimens, but not actively inflamed terminal ileum specimens, of CD patients. Our findings mechanistically reveal how genetic and microbial factors drive the manifestation of disease in a region-specific manner and provide a unique model to study CD specific to the ascending colon.
Authors
Paige N. Spencer, Monica E. Brown, Erin P. Smith, Jiawei Wang, William Kim, Luisella Spiga, Naila Tasneem, Alan J. Simmons, Taewoo Kim, Yilin Yang, Yanwen Xu, Lin Zheng, James Ro, Harsimran Kaur, Seung Woo Kang, Matthew D. Helou, Mason A. Lee, Deronisha Arceneaux, Katherine D. Mueller, Ozge S. Kuddar, Mariah H. Harned, Jing Li, Amrita Banerjee, Nicholas O. Markham, Keith T. Wilson, Lori A. Coburn, Jeremy A. Goettel, Qi Liu, M. Kay Washington, Raphael H. Valdivia, Wenhan Zhu, Ken S. Lau
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Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)