Zhilin Li

Epilepsy is a prevalent neurological disorder characterized by recurrent seizures, chronic neuroinflammation, and progressive neurodegeneration. While neuronal hyperexcitability has been extensively studied, the contribution of glial interactions-particularly between astrocytes and microglia-remains poorly understood. Here, we identify the astrocyte–microglia IL-3–IL-3Rα signaling axis as a critical mediator of neuroinflammatory and neurodegenerative responses following status epilepticus (SE). In a pilocarpine-induced SE mouse model, we observed increased expression of interleukin-3 (IL-3) in astrocytes and its receptor IL-3Rα in microglia within the hippocampus. In vitro, IL-3 stimulation induced robust production of pro-inflammatory cytokines (IL-1β, TNF-α, and iNOS) in BV-2 microglia via the JAK2/STAT5 signaling pathway, an effect significantly attenuated by the selective JAK2 inhibitor AG490. In vivo, AG490 treatment reduced seizure severity, suppressed epileptiform EEG discharges, alleviated hippocampal inflammation, and importantly, mitigated SE-induced neuronal loss and nuclear damage in the hippocampus. Collectively, our data demonstrate that the IL-3-IL-3Rα-JAK2/STAT5 signaling axis, while known in other contexts, is a critical mediator of glial communication and pathology in the post-seizure brain, offering a promising target for therapeutic intervention in epilepsy.

Discovery of meningeal lymphatic vessels (LVs) in the dura mater, also known as dural LVs (dLVs) that depend on vascular endothelial growth factor C expression, has raised interest in their possible involvement in Alzheimer’s disease (AD). Here we find that in the APdE9 and 5xFAD mouse models of AD, dural amyloid-β (Aβ) is confined to blood vessels and dLV morphology or function is not altered. The induction of sustained dLV atrophy or hyperplasia in the AD mice by blocking or overexpressing vascular endothelial growth factor C, impaired or improved, respectively, macromolecular cerebrospinal fluid (CSF) drainage to cervical lymph nodes. Yet, sustained manipulation of dLVs did not significantly alter the overall brain Aβ plaque load. Moreover, dLV atrophy did not alter the behavioral phenotypes of the AD mice, but it improved CSF-to-blood drainage. Our results indicate that sustained dLV manipulation does not affect Aβ deposition in the brain and that compensatory mechanisms promote CSF clearance.

The recent discovery of lymphatic vessels (LVs) in the dura mater, the outermost layer of meninges around the central nervous system (CNS), has opened a possibility for the development of alternative therapeutics for CNS disorders. The vascular endothelial growth factor C (VEGF-C)/VEGF receptor 3 (VEGFR3) signaling pathway is essential for the development and maintenance of dural LVs. However, its significance in mediating dural lymphatic function in CNS autoimmunity is unclear. We show that inhibition of the VEGF-C/VEGFR3 signaling pathway using a monoclonal VEGFR3-blocking antibody, a soluble VEGF-C/D trap, or deletion of the Vegfr3 gene in adult lymphatic endothelium causes notable regression and functional impairment of dural LVs but has no effect on the development of CNS autoimmunity in mice. During autoimmune neuroinflammation, the dura mater was only minimally affected, and neuroinflammation-induced helper T (T _H ) cell recruitment, activation, and polarization were significantly less pronounced in the dura mater than in the CNS. In support of this notion, during autoimmune neuroinflammation, blood vascular endothelial cells in the cranial and spinal dura expressed lower levels of cell adhesion molecules and chemokines, and antigen-presenting cells (i.e., macrophages and dendritic cells) had lower expression of chemokines, MHC class II–associated molecules, and costimulatory molecules than their counterparts in the brain and spinal cord, respectively. The significantly weaker T _H cell responses in the dura mater may explain why dural LVs do not contribute directly to CNS autoimmunity.

Objective. (1) To propose a novel technique named thoracic extensive laminoplasty (TELP) in curing severe thoracic ligamentum flavum ossification (STOLF) and (2) to compare outcomes between TELP and laminectomy in curing STOLF. Methods. Cases with fused or tuberous STOLF (Sato classification) treated from Jan 2015 to Jan 2017 were reviewed and divided into the TELP group (G1) and laminectomy group (G2) according to their surgical management. Data on demographics, complications, pre‐ and postoperative symptoms, residual spinal canal area (RSCA‐1), residual spinal cord area (RSCA‐2), modified Japanese Orthopedic Association score (mJOA), and health‐related quality of life (HRQOL, based on the SF‐36) were collected. Results. Fifty‐nine G1 and sixty‐two G2 patients were enrolled. No significant differences in demographic data or preoperative data of RSCA‐1, RSCA‐2, mJOA, or HRQOL were observed between the two groups (p > 0.05). Patients in G1 and G2 showed similar postoperative improvements in RSCA‐1 and RSCA‐2 at the final follow‐up (p > 0.05). However, patients in G1 showed higher postoperative improvements in mJOA (OR = 2.706, 95% CI: 1.279~5.727, p = 0.008) at the final follow‐up. Patients in G1 also showed higher postoperative improvements in HRQOL than patients in G2 (p < 0.05) at the final follow‐up, and patients with more severe STOLF presented with better improvements in HRQOL in G1 (p < 0.05). Dural laceration and cerebrospinal fluid leakage were observed in seven G2 patients, and no complications were found in G1 patients after surgery. Conclusion. TELP is a novel, effective, and safer surgical technique in treating STOLF and could be a substitute for traditional laminectomy.

The High Mobility Group Box 1 (HMGB1) is the most abundant nuclear nonhistone protein that is involved in transcription regulation. In addition, HMGB1 has previously been found as an extracellularly acting protein enhancing neurite outgrowth in cultured neurons. Although HMGB1 is widely expressed in the developing central nervous system of vertebrates and invertebrates, its function in the developing mouse brain is poorly understood. Here, we have analyzed developmental defects of the HMGB1 null mouse forebrain, and further examined our findings in ex vivo brain cell cultures. We find that HMGB1 is required for the proliferation and differentiation of neuronal stem cells/progenitor cells. Enhanced apoptosis is also found in the neuronal cells lacking HMGB1. Moreover, HMGB1 depletion disrupts Wnt/β-catenin signaling and the expression of transcription factors in the developing cortex, including Foxg1, Tbr2, Emx2, and Lhx6. Finally, HMGB1 null mice display aberrant expression of CXCL12/CXCR4 and reduced RAGE signaling. In conclusion, HMGB1 plays a critical role in mammalian neurogenesis and brain development.

Angiopoietin-2 (Ang2), a ligand of the endothelial Tie2 tyrosine kinase, is involved in vascular inflammation and leakage in critically ill patients. However, the role of Ang2 in demyelinating central nervous system (CNS) autoimmune diseases is unknown. Here, we report that Ang2 is critically involved in the pathogenesis of experimental autoimmune encephalomyelitis (EAE), a rodent model of multiple sclerosis. Ang2 expression was induced in CNS autoimmunity, and transgenic mice overexpressing Ang2 specifically in endothelial cells (ECs) developed a significantly more severe EAE. In contrast, treatment with Ang2-blocking Abs ameliorated neuroinflammation and decreased spinal cord demyelination and leukocyte infiltration into the CNS. Similarly, Ang2-binding and Tie2-activating Ab attenuated the development of CNS autoimmune disease. Ang2 blockade inhibited expression of EC adhesion molecules, improved blood-brain barrier integrity, and decreased expression of genes involved in antigen presentation and proinflammatory responses of microglia and macrophages, which was accompanied by inhibition of α₅β₁ integrin activation in microglia. Taken together, our data suggest that Ang2 provides a target for increasing Tie2 activation in ECs and inhibiting proinflammatory polarization of CNS myeloid cells via α₅β₁ integrin in neuroinflammation. Thus, Ang2 targeting may serve as a therapeutic option for the treatment of CNS autoimmune disease.

The recent discovery of meningeal lymphatic vessels (LVs) has raised interest in their possible involvement in neuropathological processes, yet little is known about their development or maintenance. We show here that meningeal LVs develop postnatally, appearing first around the foramina in the basal parts of the skull and spinal canal, sprouting along the blood vessels and cranial and spinal nerves to various parts of the meninges surrounding the central nervous system (CNS). VEGF-C, expressed mainly in vascular smooth muscle cells, and VEGFR3 in lymphatic endothelial cells were essential for their development, whereas VEGF-D deletion had no effect. Surprisingly, in adult mice, the LVs showed regression after VEGF-C or VEGFR3 deletion, administration of the tyrosine kinase inhibitor sunitinib, or expression of VEGF-C/D trap, which also compromised the lymphatic drainage function. Conversely, an excess of VEGF-C induced meningeal lymphangiogenesis. The plasticity and regenerative potential of meningeal LVs should allow manipulation of cerebrospinal fluid drainage and neuropathological processes in the CNS.

Progressive myoclonus epilepsy of Unverricht-Lundborg type (EPM1) is an autosomal recessively inherited childhood-onset neurodegenerative disorder, characterized by myoclonus, seizures, and ataxia. Mutations in the cystatin B gene (CSTB) underlie EPM1. The CSTB-deficient (Cstb −/− ) mouse model recapitulates key features of EPM1, including myoclonic seizures. The mice show early microglial activation that precedes seizure onset and neuronal loss and leads to neuroinflammation. We here characterized the inflammatory phenotype of Cstb −/− mice in more detail. We found higher concentrations of chemokines and pro-inflammatory cytokines in the serum of Cstb −/− mice and higher CXCL13 expression in activated microglia in Cstb −/− compared to control mouse brains. The elevated chemokine levels were not accompanied by blood-brain barrier disruption, despite increased brain vascularization. Macrophages in the spleen and brain of Cstb −/− mice were predominantly pro-inflammatory. Taken together, these data show that CXCL13 expression is a hallmark of microglial activation in Cstb −/− mice and that the brain inflammation is linked to peripheral inflammatory changes, which might contribute to the disease pathology of EPM1.