Search bioRxiv⌕ Search

Biology subjects

Zipp, F.

Publications and source records attributed to Zipp, F..

4 recordsLinked to original sources

Performance-impacting brain state maladaptation driving disease progression in early mouse and human neuroinflammation

The neuronal mechanisms driving progression in neuroinflammatory disorders from early relapse-remitting phases to later neurodegenerative phases remain largely elusive. Functional brain state shifts towards hyperactivity, persisting beyond relapses, represent an early maladaptive response. Here, in remission stage of an experimental autoimmune encephalitis (EAE) mouse model of RRMS, we identified a reduced excitability upon optogenetic stimulation in the brain stem, the area of active disease, while in the cortex a persistent cortical neuronal hyperactivity and synaptic remodeling emerged, accompanied with an increase of markers of early apoptosis. In contrast, hippocampal circuits, which undergo a functional state shift without hyperactivity, do not show increased apoptosis. Visual cortical networks showed a deterioration of the accuracy of encoding visual information and a decrease in the behavioural visual discrimination ability in mice. In RRMS patients in remission, we identified a reduced visual colour discrimination, indicating both the presence and the clinical relevance of early brain state maladaptation that may contribute to progression independent from relapse activity (PIRA). SummaryIn a RRMS model and in patients, impaired visual processing was reported, indicating brain state maladaptations, associated with persistent cortical hyperactivity, brain stem hypoactivity, synaptic remodeling, and apoptosis. These maladaptations might contribute to relapse-independent disease progression through sustained network dysfunction.

neuroscience↗

EGFL7 promotes immune evasion in glioma through its interaction with integrin β2

Glioblastoma is the most aggressive form of malignant brain cancer, characterized by an immunosuppressive microenvironment and immune evasion. Despite the success of immune checkpoint inhibitors in other cancers, immunotherapies such as anti-PD1 have shown limited efficacy in glioblastoma, underscoring the need to identify tumor-intrinsic mechanisms that sustain this immunosuppressive microenvironment and to develop more effective therapeutic strategies targeting them. Previously, the secreted factor epidermal growth factor-like protein 7 (EGFL7) has been shown to promote brain tumor growth by affecting the glioblastoma microenvironment (GME). However, its impact on the immune system remained enigmatic. Here, we studied the role of EGFL7 in shaping the immune landscape in glioblastoma and identified the underlying molecular mechanisms it engages to drive glioma immune evasion. Single-cell transcriptomic profiling of immune cells derived of glioblastoma revealed that EGFL7 promotes an immunosuppressive GME, characterized by enhanced T cell exhaustion and polarization of macrophages towards a protumorigenic state. Proteomic profiling of EGFL7s interactome in glioma revealed its interaction with integrin {beta}2 (ITGB2), an immune cell surface receptor involved in cell adhesion and migration. Mechanistic studies uncovered the central role of this interaction for immune evasion, which promoted T cell exhaustion and the polarization of macrophages towards a pro-tumorigenic state. Genetic perturbation of the EGFL7-ITGB2 axis attenuated immunosuppression and prolonged the survival of glioblastoma-bearing mice. Remarkably, a combinatorial regimen of anti-EGFL7 and the checkpoint inhibitor anti-PD1 improved the efficacy of this drug, which by itself did not improve glioma patient survival so far. In conclusion, our study provides unequivocal evidence that EGFL7 mediates immune evasion in glioma and has great potential to serve as an add-on drug target to improve immunotherapies not functional in glioblastoma patients so far.

cancer biology↗

Choroid plexus enlargement in acute neuroinflammation is tightly interrelated to the tyrosine receptor signalling

The choroid plexus (ChP) plays a crucial function in neuroinflammation of the central nervous system and in the immune response of the brain during neurodegeneration. Recent studies described a massive ChP enlargement in patients with multiple sclerosis (MS) and active disease courses, but also in several other neuroinflammatory and neurodegenerative conditions. Nevertheless, the exact basis and pathophysiology behind ChP hypertrophy remains unclear. This study was designed to evaluate the association of cerebrospinal fluid (CSF) proteomic spectra with brain MRI-derived volumetric measures of ChP in two independent cohorts of MS patients, and to translationally validate the related molecular mechanisms in the transcriptomic analysis of the ChP properties in a mouse model of experimental autoimmune encephalomyelitis (EAE). Our analysis revealed five enriched proteins (NTRK2, ADAM23, SCARB2, CPM, CNTN5) significantly associated with the ChP volumes in both of the MS cohorts. These proteins relate closely to mechanisms of cellular communication, function (e.g. transmembrane tyrosine receptor signalling (RTK) and vascular endothelial growth) and pathways involved in the regulation of cellular plasticity (e.g. neuron differentiation, axonal remodelling and myelin regulation) as depicted by molecular function analysis and validation of the results in the transcriptome from ChP tissue specific for EAE. This work provides conclusive new evidence for the role of ChP in the context of neuroinflammation and neurodegeneration, demonstrating the intriguing relationships between ChP enlargement, CSF dynamics, and the development of neuroinflammatory and neurodegenerative diseases. Our results are encouraging for the development of new therapeutic avenues (i.e. targeting RTK signalling). One sentence summaryTyrosine receptor signalling is tightly associated with choroid plexus enlargement and is key in CSF dynamics during a neuroinflammatory attack in MS

neuroscience↗

Less is more - loss of EGFL7 improves memory by upregulation of VEGF-D

Neural stem cells reside in a specialized neurogenic niche of the hippocampus termed the subgranular zone. Throughout life, they give rise to adult-born neurons in the dentate gyrus thereby contributing to learning and memory. Here, we report that neurons together with neural stem and precursor cells secrete the neurovascular protein epidermal growth factor-like protein 7 (EGFL7) to shape this niche. EGFL7 knock-out in vivo promoted adult neurogenesis generating neurons forming additional spines which permanently integrated into the neural circuit until old age. RNA-sequencing identified the cytokine VEGF-D as a major molecular driver of this process in vivo. In behavioral studies EGFL7 knock-out mice displayed stronger maintenance of memory suggesting longer-lasting spatial memory and improved memory consolidation in the hippocampus by modulation of pattern separation in young and aged mice. Taken together, EGFL7 is an upstream regulator of the VEGF-D in adult neurogenesis and a key regulator of learning and memory.

neuroscience↗