Schizophrenia is a neurodevelopmental disease characterized by cerebral connectivity impairment and loss of gray matter. It was described in adult schizophrenia patients (SZP) that concentration of VEGFA, a master angiogenic factor, is decreased. Recent evidence suggests cerebral hypoperfusion related to a dysfunctional Blood Brain Barrier (BBB) in SZP. Since neurogenesis and blood-vessel formation occur in a coincident and coordinated fashion, a defect in neurovascular development could result in increased vascular permeability and, therefore, in poor functionality of the SZP’s neurons. Here, we characterized the conditioned media (CM) of human induced Pluripotent Stem Cells (hiPSC)-derived Neural Stem Cells of SZP (SZP NSC) versus healthy subjects (Ctrl NSC), and its impact on angiogenesis. Our results reveal that SZP NSC have an imbalance in the secretion and expression of several angiogenic factors, among them non-canonical neuro-angiogenic guidance factors. SZP NSC migrated less and their CM was less effective in inducing migration and angiogenesis both in vitro and in vivo. Since SZP originates during embryonic brain development, our findings suggest a defective crosstalk between NSC and endothelial cells (EC) during the formation of the neuro-angiogenic niche.

The extraordinary plasticity of glioma cells allows them to contribute to different cellular compartments in the tumor vessels, reinforcing the vascular architecture. Recently, it was revealed that targeting glioma-derived pericytes, which represent a big percentage of the mural cell population in aggressive tumors, increases the permeability of the vessels and improves chemotherapy efficiency. However, the molecular determinants of this transdifferentiation process have not been elucidated. Here, we show that mutations in EGFR (epidermal growth factor receptor) stimulate the capacity of glioma cells to function as pericytes in a BMX (bone marrow and X-linked)/SOX9 dependent manner. The subsequent activation of PDGFR (platelet derived growth factor receptor beta) in the vessel walls of EGFR mutant gliomas stabilize the vasculature and facilitates the recruitment of immune cells. These changes in the tumor microenvironment confer a growth advantage to the tumors, although it also makes them particularly sensitive to pericyte-targeting molecules such as ibrutinib or sunitinib. In the absence of EGFR mutations, high-grade gliomas are enriched in blood vessels too but they show a highly disrupted blood-brain-barrier due to the decreased BMX/SOX9 activation and pericyte coverage, which lead to poor oxygenation, necrosis and hypoxia. Here, we identify EGFR mutations as key regulators of the glioma-to-pericyte transdifferentiation, highlighting the intricate relation between the tumor cells and their vascular and immune microenvironment.Our results lay the foundations for a vascular dependent stratification of gliomas and suggest different therapeutic vulnerabilities depending on the genetic status of EGFR, which defines the vascular and the immune landscape of the tumors.

Schizophrenia (SZ) is a complex neuropsychiatric disorder, affecting 1% of the world population. Long-standing clinical observations and molecular data have pointed out a possible vascular deficiency that could be acting synergistically with neuronal dysfunction in SZ.As SZ is a neurodevelopmental disease, the use of human induced pluripotent stem cells (hiPSC) allows disease biology modeling retaining the patient's unique genetic signature. Previously, we reported a VEGF-A signaling impairment in SZ-hiPSC derived neural lineages leading to a decreased angiogenesis. Here, we present a functional characterization of SZ-derived brain microvascular endothelial-like cells (BEC), the counterpart of the neurovascular crosstalk, revealing an intrinsically defective Blood-Brain Barrier (BBB) phenotype. Transcriptomic assessment of genes related to endothelial function among three control (Ctrl BEC) and five schizophrenia patients derived BEC (SZP BEC), revealed that SZP BEC have a distinctive expression pattern of angiogenic and BBB-associated genes. Functionally, SZP BEC showed a decreased angiogenic response in vitro and higher transpermeability than Ctrl BEC.Immunofluorescence staining revealed less expression and altered distribution of tight junction proteins in SZP BEC. Moreover, SZP BEC's secretome reduced barrier capacities in the brain microvascular endothelial cell line HCMEC/D3 and in an in vivo permeability assay in mice. Overall, our results describe an intrinsic failure of SZP BEC for proper barrier function. These findings are consistent with the hypothesis that traces schizophrenia origins to brain development and BBB dysfunction.

CaMK2N1 and CaMK2N2 (also known as CaMKIINα and β) are endogenous inhibitors of calcium/calmodulin‐dependent kinase II (CaMKII), an enzyme critical for memory and long‐term potentiation (LTP), a form of synaptic plasticity thought to underlie learning. CaMK2N1/2 mRNAs are rapidly and differentially upregulated in the hippocampus and amygdala after acquisition or retrieval of fear memory. Moreover, CaMK2N2 protein levels increase after contextual fear conditioning. Therefore, it was proposed that CaMK2N1/2 genes (Camk2n1/2) could be immediate‐early genes transcribed promptly (30–60 min) after training. As a first approach to explore a role in synaptic plasticity, we assessed a possible regulation of Camk2n1/2 during the expression phase of LTP in hippocampal CA3–CA1 connections in rat brain slices. Quantitative PCR revealed that Camk2n1, but not Camk2n2, is upregulated 60 min after LTP induction by Schaffer collaterals high‐frequency stimulation. We observed a graded, significant positive correlation between the magnitude of LTP and Camk2n1 change in individual slices, suggesting a coordinated regulation of these properties. If mRNA increment actually resulted in the protein upregulation in plasticity‐relevant subcellular locations, CaMK2N1 may be involved in CaMKII fine‐tuning during LTP maintenance or in the regulation of subsequent plasticity events (metaplasticity).

Gestational diabetes mellitus (GDM) is a common metabolic disorder, defined by high blood glucose levels during pregnancy, which affects foetal and post-natal development. However, the cellular and molecular mechanisms of this detrimental condition are still poorly understood. A dysregulation in circulating angiogenic trophic factors, due to a dysfunction of the feto-placental unit, has been proposed to underlie GDM. But even the detailed study of canonical pro-angiogenic factors like vascular endothelial growth factor (VEGF) or basic Fibroblast Growth Factor (bFGF) has not been able to fully explain this detrimental condition during pregnancy. Netrins are non-canonical angiogenic ligands produced by the stroma have shown to be important in placental angiogenesis. In order to address the potential role of Netrin signalling in GDM, we tested the effect of Netrin-1, the most investigated member of the family, produced by Wharton’s Jelly Mesenchymal Stem Cells (WJ-MSC), on Human Umbilical Vein Endothelial Cells (HUVEC) angiogenesis. WJ-MSC and HUVEC primary cell cultures from either healthy or GDM pregnancies were exposed to physiological (5 mM) or high (25 mM) d-glucose. Our results reveal that Netrin-1 is secreted by WJ-MSC from healthy and GDM and both expression and secretion of the ligand do not change with distinct experimental glucose conditions. Noteworthy, the expression of its anti-angiogenic receptor UNC5b is reduced in GDM HUVEC compared with its expression in healthy HUVEC, accounting for an increased Netrin-1 signalling in these cells. Consistently, in healthy HUVEC, UNC5b overexpression induces cell retraction of the sprouting phenotype.