Neuroscience
Abstract
The Integrator complex plays essential roles in RNA polymerase II transcription termination and RNA processing. Here, we identify INTS6, a subunit of the Integrator complex, as a novel gene associated with neurodevelopmental disorders (NDDs). Through analysis of large NDD cohorts and international collaborations, we identified 23 families harboring monoallelic likely gene-disruptive or de novo missense variants in INTS6. Phenotypic characterization revealed shared features, including language and motor delays, autism, intellectual disability, and sleep disturbances. Using a nervous-system conditional knockout (cKO) mouse model, we show that Ints6 deficiency disrupts early neurogenesis, cortical lamination, and synaptic development. Ints6 cKO mice displayed a thickened ventricular zone/subventricular zone, thinning of the cortical plate, reduced neuronal differentiation, and increased apoptosis in cortical layer 6. Behavioral assessments of heterozygous mice revealed deficits in social novelty preference, spatial memory, and hyperactivity, mirroring phenotypes observed in individuals with INTS6 variants. Molecular analyses further revealed that INTS6 deficiency alters RNA polymerase II dynamics, disrupts transcriptional regulation, and impairs synaptic gene expression. Treatment with a CDK9 inhibitor (CDK9i) reduced RNAPII phosphorylation, thereby limiting its binding to target genes. Notably, CDK9i reversed neurosphere over-proliferation and rescued the abnormal dendritic spine phenotype caused by Ints6 deficiency. This work advances understanding of INTS-related NDD pathogenesis and highlights potential therapeutic targets for intervention.
Authors
Xiaoxia Peng, Xiangbin Jia, Hanying Wang, Jingjing Chen, Xiaolei Zhang, Senwei Tan, Xinyu Duan, Can Qiu, Mengyuan Hu, Haiyan Hou, Ilaria Parenti, Alma Kuechler, Frank J. Kaiser, Alicia Renck, Raymond Caylor, Cindy Skinner, Joseph Peeden, Benjamin Cogne, Bertrand Isidor, Sandra Mercier, Gael Nicolas, Anne-Marie Guerrot, Flavio Faletra, Luciana Musante, Lior Cohen, Gaber Bergant, Goran Čuturilo, Borut Peterlin, Andrea Seeley, Kristine Bachman, Julian A. Martinez-Agosto, Conny van Ravenswaaij-Arts, Dennis Bos, Katherine H. Kim, Tobias Bartolomaeus, Zelia Schmederer, Rami Abou Jamra, Erfan Aref-Eshghi, Wenjing Zhao, Yongyi Zou, Zhengmao Hu, Qian Pan, Faxiang Li, Guodong Chen, Jiada Li, Zhangxue Hu, Kun Xia, Jieqiong Tan, Hui Guo
Abstract
Authors
Steven Q. Le, Alexander Sorensen, Soila Sukupolvi, Gianna Jewhurst, Grant L. Austin, Balraj Doray, Jonathan D. Cooper, Patricia I. Dickson
Abstract
Degeneration of the neuromuscular system is a characteristic feature of spinal and bulbar muscular atrophy (SBMA), a CAG/polyglutamine (polyQ) expansion disorder caused by mutation in the androgen receptor (AR). Using a gene targeted mouse model of SBMA, AR113Q mice, we demonstrate age-dependent degeneration of the neuromuscular system that initially manifests with muscle weakness and atrophy and progresses to include denervation of neuromuscular junctions and lower motor neuron soma atrophy. Using this model, we tested the hypothesis that therapeutic intervention targeting skeletal muscle during this period of disease progression arrests degeneration of the neuromuscular system. To accomplish this, AR-targeted antisense oligonucleotides were administered subcutaneously to symptomatic AR113Q mice to reduce expression of polyQ AR in peripheral tissues but not in the spinal cord. This intervention rescued muscle atrophy, neuromuscular junction innervation, lower motor neuron soma size, and survival in aged AR113Q mice. Single-nucleus RNA sequencing revealed age-dependent transcriptional changes in the AR113Q spinal cord during disease progression which were mitigated by peripheral AR gene silencing. Our findings underscore the intricate interplay between peripheral tissues and the central nervous system in SBMA and emphasize the therapeutic effectiveness of peripheral gene knockdown in symptomatic disease.
Authors
Changwoo Lee, Zhigang Yu, Curtis J. Kuo, Leon Tejwani, Rosalie M. Grijalva, Eunwoo Bae, Hien T. Zhao, Janghoo Lim, Andrew P. Lieberman
Abstract
The incretin receptor agonists semaglutide and tirzepatide have transformed the medical management of obesity. The neural mechanisms by which incretin analogs regulate appetite remain incompletely understood, and dissecting this process is critical for the development of next-generation anti-obesity drugs that are more targeted and tolerable. Moreover, the physiologic functions of incretins in appetite regulation and gut-brain communication have remained elusive. Using in vivo fiber photometry, we discovered distinct pharmacologic and physiologic roles for the incretin hormones glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1). We showed that GIP, but not GLP-1, was required for normal nutrient-mediated inhibition of hunger-promoting AgRP neurons. By contrast, both GIP and GLP-1 analogs at pharmacologic doses were sufficient to inhibit AgRP neurons. The magnitude of neural inhibition was proportional to the effect of each incretin on food intake, and dual GIP and GLP-1 receptor agonism more potently inhibited AgRP neurons and suppressed food intake than either agonist alone. Our results have revealed a role for endogenous GIP in gut-brain appetite regulation and indicate that incretin analogs act in part via AgRP neurons to mediate their anorectic effects.
Authors
Hayley E. McMorrow, Andrew B. Cohen, Carolyn M. Lorch, Nikolas W. Hayes, Stefan W. Fleps, Joshua A. Frydman, Jessica L. Xia, Ricardo J. Samms, Lisa R. Beutler
Abstract
Protein phosphatase 2A (PP2A) is a serine/threonine phosphatase in the brain. Mutations in PPP2R1A, encoding the scaffolding subunit, are linked to intellectual disability, although the underlying mechanisms remain unclear. This study examined mice with heterozygous deletion of Ppp2r1a in forebrain excitatory neurons (NEX-het-conditional knockout, NEX-het-cKO). These mice exhibited impaired spatial learning and memory, resembling Ppp2r1a-associated intellectual disability. Ppp2r1a haploinsufficiency also led to increased excitatory synaptic strength and reduced inhibitory synapse numbers on pyramidal neurons. The increased excitatory synaptic transmission was attributed to increased presynaptic release probability (Pr), likely due to reduced levels of 2-arachidonoyl glycerol (2-AG). This reduction in 2-AG was associated with increased transcription of monoacylglycerol lipase (MAGL), driven by destabilization of enhancer of zeste homolog 2 (EZH2) in NEX-het-cKO mice. Importantly, the MAGL inhibitor JZL184 effectively restored both synaptic and learning deficits. Our findings uncover an unexpected role of PPP2R1A in regulating endocannabinoid signaling, providing fresh molecular and synaptic insights into the mechanisms underlying intellectual disability.
Authors
Yirong Wang, Weicheng Duan, Hua Li, Zhiwei Tang, Ruyi Cai, Shangxuan Cai, Guanghao Deng, Liangpei Chen, Hongyan Luo, Liping Chen, Yulong Li, Jian-Zhi Wang, Bo Xiong, Man Jiang
Abstract
Diabetic peripheral neuropathy (DPN) is a prevalent complication of diabetes mellitus caused by metabolic toxicity to peripheral axons. We aimed to gain deep mechanistic insight into the disease using transcriptomics on tibial and sural nerves recovered from lower leg amputations in a mostly diabetic population and control sural nerves from cross facial nerve graft surgery. First, comparing DPN versus control sural nerves revealed inflammatory activation and sensory changes in DPN. Second, when comparing mixed sensory and motor tibial and purely sensory sural nerves, we identified key pathway differences in affected DPN nerves, with distinct immunological features observed in sural nerves. Third, spatial transcriptomics of sural nerves revealed shifts in immune cell types associated with axonal loss progression. We also found clear evidence of neuronal transcript changes, like PRPH, in nerves with axonal loss, suggesting perturbed RNA transport into distal sensory axons. This motivated further investigation into neuronal mRNA localization in peripheral nerve axons, generating evidence of robust localization of mRNAs such as SCN9A and TRPV1 in human sensory axons. Our work provides insight into altered cellular and transcriptomic profiles in human nerves in DPN and highlights sensory axon mRNA transport as a potential contributor to nerve degeneration.
Authors
Diana Tavares-Ferreira, Breanna Q. Shen, Juliet M. Mwirigi, Stephanie Shiers, Ishwarya Sankaranarayanan, Akshitha Sreerangapuri, Miriam B. Kotamarti, Nikhil N. Inturi, Khadijah Mazhar, Eroboghene E. Ubogu, Geneva L. Thomas, Trapper Lalli, Shai M. Rozen, Dane K. Wukich, Theodore J. Price
Abstract
Anxiety disorders pose a substantial threat to global mental health, with chronic stress identified as a major etiologic factor. Over the past few decades, extensive studies have revealed that chronic stress induces anxiety states through a distributed neuronal network of interconnected brain structures. However, the precise circuit mechanisms underlying the transition from chronic stress to anxiety remain incompletely understood. Employing the chronic social defeat stress (CSDS) paradigm in mice, we uncovered a critical role of the parasubthalamic nucleus (PSTh) in both the induction and expression of anxiety-like behavior. The anxiogenic effect was mediated by an excitatory trisynaptic circuitry involving the lateral parabrachial nucleus (LPB), PSTh, and bed nucleus of the stria terminalis (BNST). Furthermore, CSDS downregulated Kv4.3 channels in glutamatergic neurons of the PSTh. Reexpression of these channels dampened neuronal overexcitability and alleviated anxiety-like behavior in stressed animals. In parallel with the well-known anxiety network centered on the amygdala, here we identify a noncanonical LPB-PSTh-BNST pathway in the transformation of stress into anxiety. These findings suggest that the PSTh may serve as a potential therapeutic target for anxiety-related disorders.
Authors
Na Liu, Jun Wang, Huan Wang, Bin Gao, Zheng Lin, Tian-Le Xu, Shumin Duan, Han Xu
Abstract
Fibroblast growth factor homologous factors (FHFs) bind to the cytoplasmic carboxy terminus of voltage-gated sodium channels (VGSCs) and modulate channel function. Variants in FHFs or VGSCs perturbing that bimolecular interaction are associated with arrhythmias. Like some channel auxiliary subunits, FHFs exert additional cellular regulatory roles, but whether these alternative roles affect VGSC regulation is unknown. Using a separation-of-function strategy, we show that a structurally guided, binding incompetent mutant FGF13 (the major FHF in mouse heart) confers complete regulation of VGSC steady-state inactivation (SSI), the canonical effect of FHFs. In cardiomyocytes isolated from Fgf13 knockout mice, expression of the mutant FGF13 completely restores wild-type regulation of SSI. FGF13 regulation of SSI derives from effects on local accessible membrane cholesterol, which is unexpectedly polarized and concentrated in cardiomyocytes at the intercalated disc (ID) where most VGSCs localize. Fgf13 knockout eliminates the polarized cholesterol distribution and causes loss of VGSCs from the ID. Moreover, we show that the previously described FGF13-dependent stabilization of VGSC currents at elevated temperatures depends on the cholesterol mechanism. These results provide new insights into how FHFs affect VGSCs and alter the canonical model by which channel auxiliary subunits exert influence.
Authors
Aravind R. Gade, Mattia Malvezzi, Lala Tanmoy Das, Maiko Matsui, Cheng-I J. Ma, Keon Mazdisnian, Steven O. Marx, Frederick R. Maxfield, Geoffrey S. Pitt
Abstract
The comorbidity of depressive symptoms in chronic pain has been recognized as a key health issue. However, whether discrete circuits underlie behavioral subsets of chronic pain and comorbid depression has not been addressed. Here, we report that dopamine 2 (D2) receptor–expressing medium spiny neurons in the nucleus accumbens medial shell (mNAcSh) mediate pain hypersensitivity and depression-like behaviors in mice after nerve injury. Two separate neural pathways mediate different symptoms. The glutamatergic inputs from the anteromedial thalamic nucleus to mNAcSh D2 neurons that innervated orexin-expressing neurons in the lateral hypothalamic area contributed to pain regulation. In contrast, the lateral septum GABAergic inputs to mNAcSh D2 neurons that disinhibit the ventral pallidum glutamatergic neurons mediated depression-like behaviors. These findings indicate the functional significance of heterogeneous mNAcSh D2 neurons and their neural pathways, providing a perspective for symptom-specific treatments of chronic pain and comorbid depression.
Authors
Di Liu, Fang-Xia Xu, Zhuang Yu, Xiao-Jing Huang, Ya-Bing Zhu, Li-Juan Wang, Chen-Wei Wu, Xu Zhang, Jun-Li Cao, Jinbao Li
Abstract
Authors
Elena Godoy-Molina, Natalia L. Serrano, Aquilina Jiménez-González, Miquel Villaronga, Rosa M. Marqués Pérez-Bryan, Rubén Varela-Fernández, Stephanie Lotz-Esquivel, Alba Hevia Tuñón, Prachi P. Trivedi, Nina Horn, Joseph F. Standing, Víctor Mangas-Sanjuan, Mercè Capdevila, Aurora Mateos, Denis Broun, Svetlana Lutsenko, Ines Medina-Rivera, Rafael Artuch, Cristina Jou, Mònica Roldán, Pedro Arango-Sancho, Mónica Saez-Villafañe, Juan J. Ortiz-de-Urbina, Angela Pieras-López, Marta Duero, Rosa Farré, Jordi Pijuan, Janet Hoenicka, James C. Sacchettini, Michael J. Petris, Vishal M. Gohil, Francesc Palau
Copyright © 2025 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)