Single-cell transcriptomic analysis of the tumor microenvironment and inferred cell–cell communication in NF2-related schwannomatosis and sporadic vestibular schwannomas

NF2-related schwannomatosis (NF2-SWN) vestibular schwannomas (VS) can show clinically aggressive behavior and pronounced vascularization, but their tumor microenvironment (TME) and its relationship to sporadic VS remain incompletely defined. We performed single-cell RNA sequencing (scRNA-seq) on three NF2-SWN and three sporadic VS specimens to characterize cell states and generate hypotheses about intercellular communication. Selected observations were assessed by multiplex immunohistochemistry and by endothelial-cell migration and tube-formation assays; the effects of NRP2 knockdown on VEGFR2/ERK/AKT signaling were examined in HUVECs. We identified 25 cell clusters spanning Schwann, immune, and stromal populations. Because the biological replicate was the patient and only three tumors were available per group, between-group comparisons were considered exploratory. NK/NKT-associated cytotoxic programs were prominent, whereas few CD4-associated T cells were recovered; technical effects of tissue dissociation and sampling preclude interpreting this as biological absence. CellChat inferred group-associated differences in communication categories including CXCL, TNF, MK, NEGR, and SEMA3, but these expression-based predictions do not establish pathway activation or causal signaling mechanisms. NRP2 transcripts were concentrated in the endothelial cluster, and NRP2 knockdown reduced HUVEC migration and tube formation together with VEGFR2, ERK, and AKT phosphorylation. This study provides an exploratory single-cell description of NF2-SWN and sporadic VS and identifies endothelial NRP2 as a candidate associated with angiogenesis-related phenotypes in vitro. Independent cohorts, patient-level analyses, and rescue or in vivo studies are required before disease-specific or causal conclusions can be established.