CHMP2B
Charged multivesicular body protein 2b (CHMP2.5) (Chromatin-modifying protein 2b) (CHMP2b) (Vacuolar protein sorting-associated protein 2-2) (Vps2-2) (hVps2-2) [CGI-84]
Publications[править]
In frontotemporal dementia (FTD) there is a critical lack in the understanding of biological and molecular mechanisms involved in disease pathogenesis. The heterogeneous genetic features associated with FTD suggest that multiple disease-mechanisms are likely to contribute to the development of this neurodegenerative condition. We here present a systems biology approach with the scope of i) shedding light on the biological processes potentially implicated in the pathogenesis of FTD and ii) identifying novel potential risk factors for FTD. We performed a gene co-expression network analysis of microarray expression data from 101 individuals without neurodegenerative diseases to explore regional-specific co-expression patterns in the frontal and temporal cortices for 12 genes (MAPT, GRN, CHMP2B, CTSC, HLA-DRA, TMEM106B, C9orf72, VCP, UBQLN2, OPTN, TARDBP and FUS) associated with FTD and we then carried out gene set enrichment and pathway analyses, and investigated known protein-protein interactors (PPIs) of FTD-genes products. Gene co-expression networks revealed that several FTD-genes (such as MAPT and GRN, CTSC and HLA-DRA, TMEM106B, and C9orf72, VCP, UBQLN2 and OPTN) were clustering in modules of relevance in the frontal and temporal cortices. Functional annotation and pathway analyses of such modules indicated enrichment for: i) DNA metabolism, i.e. transcription regulation, DNA protection and chromatin remodelling (MAPT and GRN modules); ii) immune and lysosomal processes (CTSC and HLA-DRA modules), and; iii) protein meta/catabolism (C9orf72, VCP, UBQLN2 and OPTN, and TMEM106B modules). PPI analysis supported the results of the functional annotation and pathway analyses. This work further characterizes known FTD-genes and elaborates on their biological relevance to disease: not only do we indicate likely impacted regional-specific biological processes driven by FTD-genes containing modules, but also do we suggest novel potential risk factors among the FTD-genes interactors as targets for further mechanistic characterization in hypothesis driven cell biology work.
MeSH Terms
- Aging
- Animals
- Brain Mapping
- Frontotemporal Dementia
- Gene Regulatory Networks
- Genetic Predisposition to Disease
- Intercellular Signaling Peptides and Proteins
- Mutation
- Risk Factors
- tau Proteins
Mutations in the charged multivesicular body protein 2B (CHMP2B) gene cause frontotemporal lobar degeneration. The mutations lead to C-terminal truncation of the CHMP2B protein. We generated Chmp2b knockout mice and transgenic mice expressing either wild-type or C-terminally truncated mutant CHMP2B. The transgenic CHMP2B mutant mice have decreased survival and show progressive neurodegenerative changes including gliosis and increasing accumulation of p62- and ubiquitin-positive inclusions. The inclusions are negative for the TAR DNA binding protein 43 and fused in sarcoma proteins, mimicking the inclusions observed in patients with CHMP2B mutation. Mice transgenic for mutant CHMP2B also develop an early and progressive axonopathy characterized by numerous amyloid precursor protein-positive axonal swellings, implicating altered axonal function in disease pathogenesis. These findings were not observed in Chmp2b knockout mice or in transgenic mice expressing wild-type CHMP2B, indicating that CHMP2B mutations induce degenerative changes through a gain of function mechanism. These data describe the first mouse model of dementia caused by CHMP2B mutation and provide new insights into the mechanisms of CHMP2B-induced neurodegeneration.
MeSH Terms
- Aging
- Animals
- Axons
- Blotting, Western
- Endosomal Sorting Complexes Required for Transport
- Frontotemporal Dementia
- Gliosis
- Humans
- Immunohistochemistry
- Inclusion Bodies
- Introns
- Kaplan-Meier Estimate
- Mice
- Mice, Knockout
- Mice, Transgenic
- Microscopy, Electron
- Nerve Degeneration
- Neurons
- RNA
- Real-Time Polymerase Chain Reaction
- Survival Analysis