Neuroscience
Abstract
Mild traumatic brain injury (mTBI) from closed-head injuries (CHI) can lead to prevalent neuropsychiatric disorders, including mood disorders and an increased risk for neurodegenerative diseases and dementia. Inflammasomes are molecular complexes crucial for neuroinflammation and secondary damage after trauma, however their role in mild CHI is poorly understood. In this study, we investigate the cellular expression of inflammasome-related genes and their functional significance in CHI models. Single-cell RNA sequencing analysis of cortical tissue after trauma revealed selective expression of Asc (also known as Pycard), which encodes the inflammasome adaptor Apoptosis-associated Speck-like protein containing a Caspase recruitment domain (ASC), predominantly in microglial clusters. Sustained upregulation of inflammasome-related proteins, microglia activation and astrocyte reactivity persisted up to 21 days in a model for mTBI, with this pattern significantly reduced in Asc-/- mice. Importantly, mild cognitive impairment induced after mild CHI was largely abrogated in Asc-/- mice. These findings suggest that ASC, as the primary inflammasome adaptor, plays a critical role in sustaining neuroinflammation and contributes to cognitive deficits after mild CHI. This study provides insights into the molecular neuroinflammatory mechanisms underlying CHI, potentially informing future therapeutic strategies.
Authors
Tao Li, Sergio Castro-Gomez, Pablo Botella Lucena, Ana Vieira-Saecker, Stephanie Schwartz, Yingying Ding, Yushuang Deng, Maling Guo, Valentin Stein, Douglas T. Golenbock, Eicke Latz, Michael T. Heneka
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
Circulating monocyte-derived macrophages (MDMø) rapidly invade the brain after stroke, exerting both detrimental and beneficial effects. Elucidating mechanisms that mediate detrimental properties of MDMø may identify therapeutic strategies to divert MDMø from destructive phenotypes, while preserving their favorable effects. Toward this goal, the current study explores the function of Galectin-3 (GAL3) in MDMø and elucidates mechanisms whereby MDMø-derived GAL3 exacerbates stroke injury. In the acutely injured brain, GAL3 expression was upregulated primarily within MDMø. Global knockout of GAL3 reduced brain infarcts in the short-term but did not sustain long-term positive outcomes. Using bone marrow chimera mice, macrophage transplantation, and myeloid cell-specific GAL3 knockout (LysMCre+/–Lgals3f/f) mice, we demonstrated that GAL3 in MDMø mediated acute infarct expansion after stroke. Coculturing brain lysate-treated bone marrow-derived macrophages (BMDMs) with oxygen glucose deprivation-challenged neurons induced neurotoxicity that was mitigated by the cell-permeable, selective GAL3 inhibitor TD139. GAL3 triggered cathepsin induction and lysosomal leakage in BMDMs, leading to inflammasome activation. Systemic and transient TD139 treatment in the acute injury phase reduced infarcts, tempered neuroinflammation, and improved long-term neurological outcomes. Therefore, MDMø-derived GAL3 represents a drug target that could be accessed in peripheral blood to potentially mitigate post-stroke brain injury.
Authors
Miao Wang, Zhentai Huang, Zhihong Du, Jiajing Shan, Qing Ye, Lingxiao Lu, Ming Jiang, Fei Xu, Ziyang Liu, David J.R. Fulton, Rehana K. Leak, Babak Razani, Jun Chen, Xiaoming Hu
Abstract
Authors
Stephen G. Kaler
Abstract
Alternative splicing-triggered nonsense-mediated mRNA decay (AS-NMD) critically regulates gene expression, but the extent to which neuronal genes are regulated by AS-NMD remains understudied. Here, we identified more than 3,000 developmentally regulated AS-NMD exons in mouse and human brains, and validated them in cultured neurons. AS-NMD suppresses synaptic genes during brain development and differentially regulates more than 200 causal genes for neurodevelopmental disorders (NDDs). We detected an AS-NMD exon in GRIA2 and identified splice-switching antisense oligonucleotides that suppressed GRIA2 NMD and increased its functional isoforms. In summary, this study uncovers genes repressed by AS-NMD in the brain and nominates amenable splice-switching targets for treating dominant NDDs such as autism spectrum disorders and developmental epileptic encephalopathy.
Authors
Kaining Hu, Runwei Yang, Jiaming Qiu, Xinran Feng, Kayleigh J. LaPre, Jessica Tanouye, Yalan Yang, Xiaochang Zhang
Abstract
Prion diseases are a family of transmissible, neurodegenerative conditions caused by mis-folded proteins called prions. Human cerebral organoids can be infected with prions from sporadic Creutzfeldt-Jakob Disease (sCJD) brain tissue. Initial experiments indicated that the cerebral organoids may be able to differentiate biological properties of different sCJD subtypes and, if so, it would be possible to investigate the pathogenic similarities and differences. Herein, we investigated multiple infections of cerebral organoids with two sCJD subtypes, comparing hallmark features of disease as well as neuronal function and health. Our results show that while all infections produced seeding capable PrP, which increased from 90-180 days post infection, a sCJD subtype preference for protease resistant PrP deposition was observed. Both subtypes caused substantial electrophysiological dysfunction in the infected organoids, which appeared uncoupled from PrP deposition. Neuronal dysfunction was associated with changes in neurotransmitter receptors that differed between the subtypes but produced the same outcome of a shift from inhibitory toward excitatory neurotransmission. Further changes indicated shared deficits in mitochondrial dynamics, and subtype influenced alterations in intracellular signaling pathways, cytoskeletal structure, and the extracellular matrix. We conclude that cerebral organoids demonstrate both common mitochondrial deficits and sCJD subtype specific changes in neurotransmission and organoid architecture.
Authors
Katie Williams, Bradley R. Groveman, Simote T. Foliaki, Brent Race, Arielle Hay, Ryan O. Walters, Tina Thomas, Gianluigi Zanusso, James A. Carroll, Cathryn L. Haigh
Abstract
Neutrophils and neutrophil extracellular traps (NETs) contribute to early neuromyelitis optica (NMO) histopathology initiated by IgG targeting astrocytic aquaporin-4 water (AQP4) channels. Yet, the mechanisms underlying neutrophil recruitment and their pathogenic roles in disease progression remain unclear. To investigate molecular-cellular events preceding classical complement cascade activation in a mouse NMO model, we continuously infused, via spinal subarachnoid route, a non-complement-activating mouse monoclonal AQP4-IgG. Parenchymal infiltration of netting neutrophils containing C5a ensued with microglial activation and motor impairment, but no blood–brain barrier leakage. Motor impairment and neuronal dysfunction both reversed when AQP4-IgG infusion stopped. Two-photon microscopy and electron-microscopy-based reconstructions revealed physical interaction of infiltrating neutrophils with microglia. Ablation of either peripheral neutrophils or microglia attenuated the motor deficit, highlighting their synergistic pathogenic roles. Of note, mice lacking complement receptor C5aR1 exhibited reduction in neutrophil infiltration, microglial lysosomal activation, neuronal lipid-droplet burden and motor impairment. Pharmacological inhibition of C5aR1 recapitulated this protection. Immunohistochemical analysis of an NMO patient’s spinal cord revealed disease-associated microglia surrounding motor neurons in non-destructive lesions. Our study identifies neutrophil-derived C5a signaling through microglial C5aR1 as a key early driver of reversible motor neuron dysfunction in the precytolytic phase of NMO.
Authors
Fangfang Qi, Vanda A. Lennon, Shunyi Zhao, Yong Guo, Husheng Ding, Caiyun Liu, Whitney M. Bartley, Tingjun Chen, Claudia F. Lucchinetti, Long-Jun Wu
Abstract
Vision begins in the outer segment compartment of photoreceptor cells, which is constantly renewed through the addition of membrane material at its base and ingestion of mature membranes at its tip by the retinal pigment epithelium (RPE). The close apposition of outer segments to the RPE is believed to be critical for maintaining this renewal process. Yet, in several retinal diseases, expansion of the subretinal space separating photoreceptors from the RPE does not immediately impact photoreceptor functionality. Here, we analyzed outer segment function and renewal in the Adam9 knockout mouse characterized by a major expansion of the subretinal space. Surprisingly, photoreceptor-RPE separation affected neither the sensitivity of photoreceptor light-responses nor the normal rate of outer segment renewal in this mouse prior to the onset of photoreceptor degeneration. The latter is achieved through the formation of elongated RPE “pseudopods” extending across the enlarged subretinal space to ingest outer segment tips. This work suggests that pseudopod formation may underlie the persistence of photoreceptor function in human diseases accompanied by photoreceptor-RPE separation, such as vitelliform macular dystrophy or age-related macular degeneration associated with subretinal drusenoid deposits.
Authors
Tylor R. Lewis, Carson M. Castillo, Sebastien Phan, Camilla R. Shores, Kylie K. Hayase, Keun-Young Kim, Mark H. Ellisman, Oleg Alekseev, Marie E. Burns, Vadim Y. Arshavsky
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)