Cadherins

While single-cell technologies have greatly advanced our comprehension of human brain cell types and functions, studies including large numbers of donors and multiple brain regions are needed to extend our understanding of brain cell heterogeneity. Integrating atlas-level single-cell data presents a chance to reveal rare cell types and cellular heterogeneity across brain regions. Here we present the Brain Cell Atlas, a comprehensive reference atlas of brain cells, by assembling single-cell data from 70 human and 103 mouse studies of the brain throughout major developmental stages across brain regions, covering over 26.3 million cells or nuclei from both healthy and diseased tissues. Using machine-learning based algorithms, the Brain Cell Atlas provides a consensus cell type annotation, and it showcases the identification of putative neural progenitor cells and a cell subpopulation of PCDH9high microglia in the human brain. We demonstrate the gene regulatory difference of PCDH9high microglia between hippocampus and prefrontal cortex and elucidate the cell-cell communication network. The Brain Cell Atlas presents an atlas-level integrative resource for comparing brain cells in different environments and conditions within the Human Cell Atlas.

Epithelial barriers serve as critical defense lines against microbial infiltration and maintain tissue homeostasis. E-cadherin, an essential component of adherens junctions, has emerged as a pivotal molecule that secures epithelial homeostasis. Lately, its pleiotropic role beyond barrier function, including its involvement in immune responses, has become more evident. Herein, we delve into the intricate relationship between (dys)regulation of epithelial homeostasis and the versatile functionality of E-cadherin, describing complex mechanisms that underlie barrier integrity and disruption in disease pathogenesis such as bacterial infection and inflammation, among others. Clinical implications of E-cadherin perturbations in host pathophysiology are emphasized; downregulation, proteolytic phenomena, abnormal localization/signaling and aberrant immune reactions are linked with a broad spectrum of pathology beyond infectious diseases. Finally, potential therapeutic interventions that may harness E-cadherin to mitigate barrier-associated tissue damage are explored. Overall, this review highlights the crucial role of E-cadherin in systemic health, offering insights that could pave the way for strategies to reinforce/restore barrier integrity and treat related diseases.

Western equine encephalitis virus (WEEV) is an arthropod-borne virus (arbovirus) that frequently caused major outbreaks of encephalitis in humans and horses in the early twentieth century, but the frequency of outbreaks has since decreased markedly, and strains of this alphavirus isolated in the past two decades are less virulent in mammals than strains isolated in the 1930s and 1940s1-3. The basis for this phenotypic change in WEEV strains and coincident decrease in epizootic activity (known as viral submergence3) is unclear, as is the possibility of re-emergence of highly virulent strains. Here we identify protocadherin 10 (PCDH10) as a cellular receptor for WEEV. We show that multiple highly virulent ancestral WEEV strains isolated in the 1930s and 1940s, in addition to binding human PCDH10, could also bind very low-density lipoprotein receptor (VLDLR) and apolipoprotein E receptor 2 (ApoER2), which are recognized by another encephalitic alphavirus as receptors4. However, whereas most of the WEEV strains that we examined bind to PCDH10, a contemporary strain has lost the ability to recognize mammalian PCDH10 while retaining the ability to bind avian receptors, suggesting WEEV adaptation to a main reservoir host during enzootic circulation. PCDH10 supports WEEV E2-E1 glycoprotein-mediated infection of primary mouse cortical neurons, and administration of a soluble form of PCDH10 protects mice from lethal WEEV challenge. Our results have implications for the development of medical countermeasures and for risk assessment for re-emerging WEEV strains.

BackgroundGlioblastoma (GBM) is characterized by high invasiveness and metabolic heterogeneity. Protein Tyrosine Phosphatase Receptor Type Z1 (PTPRZ1) has been implicated in glioma stemness and tumor grade progression, while the molecular mechanism remains unknown.MethodsIntegrated bioinformatics analysis of TCGA dataset and TMA IHC profiling were used to explore clinical relevance of PTPRZ1, and potential molecular mechanisms of PTPRZ1 involved glioma progression. Ivy Glioblastoma datasets analysis and multiregional GBM IHC were performed to spatially characterize the expression patterns of PTPRZ1 in GBM tissues. Zebrafish xenograft model was established to elucidate the role of PTPRZ1 in driving glioblastoma cell migration. Western blotting, mitochondrial functional assays, Transwell migration assays, and human GBM tissue multiplexing were employed to investigate the mechanism of PTPRZ1 mediated glioma cell mobility via maintaining mitochondrial functions.ResultsSpatial profiling revealed that PTPRZ1 is significantly enriched in the infiltrating areas and peritumoral margins of GBM, and acts as a poor prognosis factor in lower grade astrocytoma, proneural and mesenchymal GBM. Mechanistically, PTPRZ1 expression was found to be strongly correlated with cell adhesion molecules (CAMs) and mitochondrial metabolism across multiple glioma subtypes. Knockdown of PTPRZ1 triggered a shift from elongated to fragmented mitochondrial morphology by specifically downregulating the mitochondrial fusion protein OPA1. This mitochondrial dysfunction led to a metabolic shift toward glycolysis and a marked accumulation of ROS, which suppressed N-cadherin expression, thereby impairing glioma cell migration. These findings were corroborated in vivo, where PTPRZ1 depletion significantly reduced disseminated tumor foci in a zebrafish model.ConclusionOur study demonstrates that PTPRZ1 drives glioblastoma migration by sustaining an OPA1-dependent mitochondrial fusion program, which suppresses mitochondrial ROS levels and subsequently stabilizes a pro-migratory phenotype via N-cadherin expression. Targeting the PTPRZ1/OPA1/ROS axis represents a promising therapeutic strategy to inhibit the invasive expansion of GBM cells.