Neuroscience
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
Abstract
SCN8A encodes the voltage-gated sodium channel Nav1.6, which plays a key role in facilitating neuronal excitability. Mutations in SCN8A, particularly gain-of-function variants, cause SCN8A developmental and epileptic encephalopathy (DEE), a severe epilepsy syndrome characterized by seizures, cognitive dysfunction, movement disorders, and sudden unexpected death in epilepsy (SUDEP). The recurrent SCN8A variant R1872W impairs channel inactivation, causing neuronal hyperexcitability and seizures. Current treatments, including antiseizure medications, are often ineffective for patients with SCN8A DEE, highlighting the need for targeted therapies. We employed base editing to correct the R1872W SCN8A variant. An adenine base editor and guide RNA (SCN8A-ABE) were packaged within dual PhP.eB-adeno-associated viruses (AAVs) and administered to R1872W mice at P2. SCN8A-ABE significantly increased survival of mice expressing R1872W and either reduced seizure incidence and severity or eliminated seizure occurrence. Electrophysiological recordings revealed a rescue of seizure-associated neuronal hyperexcitability and suppression of the pathogenic persistent sodium current (INaP) in treated mice. Comorbidities, including diminished mobility and anxiety-like behaviors, were improved by SCN8A-ABE. These effects were achieved by a 32% absolute reduction in mutant transcripts, accompanied by conversion to SCN8A WT transcripts. Our findings demonstrate base editing as an effective targeted therapeutic approach for SCN8A DEEs by addressing the underlying genetic cause.
Authors
Caeley M. Reever, Alexis R. Boscia, Tyler C.J. Deutsch, Mansi P. Patel, Raquel M. Miralles, Shrinidhi Kittur, Erik J. Fleischel, Atum M.L. Buo, Matthew S. Yorek, Miriam H. Meisler, Charles R. Farber, Manoj K. Patel
Abstract
Atypical dopamine transporter (DAT) deficiency syndrome (DTDS) arises from genetic disruption of DAT function and is characterized by early-onset parkinsonism alongside comorbid psychiatric symptoms. However, the underlying pathobiological processes are largely unknown. Here, we present a mouse model of atypical DTDS based on the patient-derived compound heterozygote genotype, DAT-I312F/D421N+/+. DAT-I312F/D421N+/+ mice exhibited markedly impaired DAT function, leading to widespread changes in dopamine homeostasis, including elevated extracellular dopamine levels, reduced tyrosine hydroxylase and dopamine D1/D2 receptor expression, and decreased evoked dopamine release, mechanistically linked to enhanced tonic D2 autoreceptor inhibition. Fiber photometry measurements revealed disrupted fast striatal dopamine release dynamics, while confocal imaging showed reduced striatal dopaminergic axon fiber density. These neurochemical changes were accompanied by a psychomotor phenotype characterized by hyperlocomotion, enhanced exploration and pronounced clasping. Both amphetamine and anticholinergic treatment ameliorated the aberrant hyperactivity. Notably, amphetamine-induced dopamine release was profoundly blunted in ventral striatum but largely preserved in dorsal striatum, implicating region-specific dopamine release dynamics as a determinant of divergent behavioral and pharmacological responses. Summarized, our findings uncover multiscale dopamine dysfunction that links presynaptic DAT impairment to synaptic and circuit-level disruptions, offering insight into atypical DTDS and the co-occurrence of movement and psychiatric features.
Authors
Freja Herborg, Lisa K. Konrad, Søren H. Jørgensen, Jamila H. Lilja, Benoît Delignat-Lavaud, Leonie P. Posselt, Ciara F. Pugh, Sofie A. Bach, Cecilia F. Ratner, Nora Awadallah, Jose A. Pino, Frida Berlin, Aske L. Ejdrup, Mikkel V. Olesen, Mattias Rickhag, Birgitte Holst, Susana Aznar, Felix P. Mayer, David Woldbye, Gonzalo E. Torres, Louis-Eric Trudeau, Ulrik Gether
Abstract
Protectin DX (PDX) is a member of the superfamily of specialized proresolving mediators and exerts anti-inflammatory actions in animal models; however, its signaling mechanism remains unclear. Here, we demonstrate the analgesic actions of PDX in a mouse model of tibial fracture–induced postoperative pain (fPOP). Intravenous early- and late-phase treatment of PDX (100 ng/mouse) effectively alleviated fPOP. Compared with protectin D1 (PD1)/neuroprotectin D1, DHA, steroids, and meloxicam, PDX provided superior pain relief. While dexamethasone and meloxicam prolonged fPOP, PDX shortened the pain duration. The analgesic effects of PDX were abrogated in Gpr37−/− mice, which displayed deficits in fPOP resolution. PDX was shown to bind GPR37 and induce calcium responses in peritoneal macrophages. LC-MS/MS–based lipidomic analysis revealed that endogenous PDX levels were approximately 10-fold higher than those of PD1 in muscle at the fracture site. PDX promoted macrophage polarization via GPR37-dependent phagocytosis and efferocytosis through calcium signaling in vitro, and it further enhanced macrophage viability and efferocytosis in vivo via GPR37. Finally, PDX rapidly modulated nociceptor neuron responses by suppressing C-fiber–induced muscle reflex in vivo and calcium responses in DRG neurons ex vivo and by reducing TRPA1/TRPV1-induced acute pain and neurogenic inflammation in vivo. Our findings highlight multiple benefits of PDX to manage postoperative pain and promote perioperative recovery.
Authors
Yize Li, Sangsu Bang, Jasmine Ji, Jing Xu, Min Lee, Sharat Chandra, Charles N. Serhan, Ru-Rong Ji
Abstract
Drug-associated environmental cues can trigger drug-seeking behavior and precipitate relapse. In the current study, we identified that the claustrum (CL) connects the ventral tegmental area (VTA) with the medial prefrontal cortex (mPFC), forming the VTA–CL–mPFC circuit. By using methamphetamine (METH) conditioned place preference (CPP) model in male mice, we found that manipulating the VTA–CL–mPFC circuit or CL neuronal ensemble receiving projections from VTA and projecting to mPFC (VTA–CL–mPFC) could disrupt the retrieval of METH-paired context memory, resulting in the blockage of the acquisition of METH CPP in male mice. During the process, dopamine (DA) release and dopamine 1-like receptor (D1R)-mediated the activation of CL neurons were required for the retrieval of METH-induced reward memory in male mice. These findings reveal a midbrain-to-cortical circuit orchestrated by CL neurons, which plays an essential role in the retrieval of drug-paired environmental cue memory.
Authors
Ziheng Zhao, Yuhong He, Yang Liu, Quying Feng, Hee Young Kim, Yu Fan, Xiaowei Guan
Copyright © 2026 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)