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Updated: Jun 29, 2025
A Novel In Vitro Live-imaging Assay of Astrocyte-mediated Phagocytosis Using pH Indicator-conjugated Synaptosomes
Published on: February 5, 2018
Microglial phagolysosome dysfunction and altered neural communication amplify phenotypic severity in Prader-Willi
Felipe Correa-da-Silva1,2,3,4, Jenny Carter5, Xin-Yuan Wang6
1Department of Endocrinology and Metabolism, Amsterdam University Medical Centers, Location AMC. University of Amsterdam, Meibergdreef 9, 1105AZ, Amsterdam, The Netherlands.
Abstract:
Prader-Willi Syndrome (PWS) is a rare neurodevelopmental disorder of genetic etiology, characterized by paternal deletion of genes located at chromosome 15 in 70% of cases. Two distinct genetic subtypes of PWS deletions are characterized, where type I (PWS T1) carries four extra haploinsufficient genes compared to type II (PWS T2). PWS T1 individuals display more pronounced physiological and cognitive abnormalities than PWS T2, yet the exact neuropathological mechanisms behind these differences remain unclear. Our study employed postmortem hypothalamic tissues from PWS T1 and T2 individuals, conducting transcriptomic analyses and cell-specific protein profiling in white matter, neurons, and glial cells to unravel the cellular and molecular basis of phenotypic severity in PWS sub-genotypes. In PWS T1, key pathways for cell structure, integrity, and neuronal communication are notably diminished, while glymphatic system activity is heightened compared to PWS T2. The microglial defect in PWS T1 appears to stem from gene haploinsufficiency, as global and myeloid-specific Cyfip1 haploinsufficiency in murine models demonstrated. Our findings emphasize microglial phagolysosome dysfunction and altered neural communication as crucial contributors to the severity of PWS T1's phenotype.
Insights
Prader-Willi Syndrome (PWS) subtypes show distinct genetic causes. Type I PWS involves more gene loss, leading to greater neurodevelopmental issues due to microglial dysfunction and altered neural communication.
Area of Science:
- Neurogenetics
- Developmental Biology
- Molecular Psychiatry
Background:
- Prader-Willi Syndrome (PWS) is a rare genetic neurodevelopmental disorder.
- PWS is caused by paternal deletion of genes on chromosome 15.
- Two subtypes, PWS T1 and PWS T2, differ in the number of haploinsufficient genes, with PWS T1 exhibiting more severe phenotypes.
Purpose of the Study:
- To investigate the neuropathological mechanisms underlying phenotypic severity differences between PWS T1 and PWS T2.
- To identify cellular and molecular distinctions in hypothalamic tissues between PWS subtypes.
Main Methods:
- Postmortem hypothalamic tissues from PWS T1 and PWS T2 individuals were analyzed.
- Transcriptomic and cell-specific protein profiling were performed on white matter, neurons, and glial cells.
- Murine models with Cyfip1 haploinsufficiency were used to study microglial defects.
Main Results:
- PWS T1 tissues showed diminished pathways for cell structure, integrity, and neuronal communication compared to PWS T2.
- Glymphatic system activity was heightened in PWS T1.
- Microglial phagolysosome dysfunction and altered neural communication were identified as key contributors to PWS T1 severity.
Conclusions:
- Genetic subtypes of PWS have distinct molecular and cellular underpinnings.
- Microglial defects, specifically phagolysosome dysfunction, are critical in the more severe PWS T1 phenotype.
- Altered neural communication pathways significantly contribute to the clinical presentation of PWS subtypes.
