Oligodendrocyte degeneration triggers the formation of inflammatory brain lesions
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ABSTRACT:
PROVIDER: PRJNA489884 | ENA |
REPOSITORIES: ENA
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Project description:Tissue progenitors maintain the integrity of organ systems through aging and stress. The brain’s white matter regions experience ischemic lesions and age-dependent degeneration. Brain white matter contains progenitors, oligodendrocyte precursor cells (OPCs), which can repair some insults. The response of OPCs to white matter ischemia and aging is not known. We characterized the response of OPCs to white matter stroke using OPC reporter mice, cell migration tracking, OPC specific RNA sequencing, and mechanistic studies in candidate biochemical pathways in the aged brain. White matter stroke induces initial proliferation of local OPCs but blocks differentiation, shunting a portion into astrocytes. Candidate signaling pathways for this differentiation block including novel interactions of inhibin and matrilin-2 and new roles of NgR1 ligands following white matter stroke. Stroke induces inhibin expression in astrocytes and downregulates OPC matrilin-2 that contributes into OPC differentiation block. Antagonism of NgR1 ligands promotes OPC differentiation by attenuating the OPC astrocytic transformation and enhances functional recovery from stroke in aged animals.
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Project description:Attaching/effacing(A/E) pathogens induce DNA damage and colorectal cancer by injecting effector proteins into host cells via the type III secretion system (T3SS). EspF is one of the T3SS-dependent effector proteins exclusive to A/E pathogens, which include enterohemorrhagicEscherichia coli(EHEC). The role of EspF in the induction of double-strand breaks (DSBs) and the phosphorylation of the repair protein SMC1 has been demonstrated previously. However, the process of damage accumulation and DSB formation has remained enigmatic, and the damage response is not well understood. Here, we first showed a compensatory increase in the mismatch repair (MMR) proteins MutS homolog 2 (MSH2) and MSH6, as well as poly(ADP-ribose) polymerase 1 (PARP1), followed by a dramatic decrease, threatening cell survival in the presence of EspF. Flow cytometry revealed that EspF arrested the cell cycle at the G2/M phase to facilitate DNA repair. Subsequently, 8-oxoguanine (8-oxoG) lesions, a marker of oxidative damage, were assayed by ELISA and immunofluorescence, which revealed the accumulation of 8-oxoG from the cytosol to the nucleus. Furthermore, the status of single-stranded DNA (ssDNA) and DSBs was confirmed. We observed that EspF accelerated the course of DNA lesions, including 8-oxoG and unrepaired ssDNA, which were converted into DSBs; this was accompanied by the phosphorylation of Replication protein A 32 (RPA32) in repair-defective cells. Collectively, these findings reveal that EspF triggers various types of oxidative DNA lesions with impairment of the DNA damage response and may result in genomic instability and cell death, offering novel insight into the tumorigenic potential of EspF.
2024-02-14 | GSE255129 | GEO
Project description:PURPOSE. During retinal degeneration, Müller glia cells respond to photoreceptor loss by undergoing reactive gliosis, with both detrimental and beneficial effects. Increasing our knowledge of the complex molecular response of Müller cells to retinal degeneration is thus essential for the development of new therapeutic strategies. The purpose of this work was to identify new factors involved in Müller cell response to photoreceptor cell death. METHODS. Whole transcriptome sequencing was performed from wild-type and degenerating rd10 mouse retinas at P30. The changes in mRNA abundance for several deregulated genes were assessed by RT-qPCR. Protein expression level and retinal cellular localization were determined by western-blot and immunohistochemistry, respectively. RESULTS. Pathway-level analysis from whole transcriptomic data revealed the Hippo/YAP pathway as one of the main signaling pathways altered in response to photoreceptor degeneration in rd10 retinas. We found that downstream effectors of this pathway, YAP and TEAD1, are specifically expressed in Müller cells and that their expression, at both the mRNA and protein levels, is increased in rd10 reactive Müller glia after the onset of photoreceptor degeneration. The expression of Ctgf and Cyr61, two target genes of the transcriptional YAP/TEAD complex, is also upregulated following photoreceptor loss. CONCLUSIONS. This work reveals for the first time that YAP and TEAD1, key downstream effectors of the Hippo pathway, are specifically expressed in Müller cells. We also uncovered a deregulation of the expression and activity of Hippo/YAP pathway components in reactive Müller cells under pathological conditions.
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Project description:Glial cytoplasmic inclusion is the pathological hallmark of multiple system atrophy commonly observed as alpha-synulcien-positive aggregates within oligodendrocytes. We elucidated that preformed alpha-synulcien fibrils triggers multimerization and upsurge of endogenous alpha-synulcien in oligodendrocyte precursor cells which is attributable to insufficient autophagic proteolysis. To assess the functional influence of alpha-synuclein fibrils application on oligodendrocyte precursor cells, RNA-seq analysis was performed. The data revealed that alpha-synulcien fibrils interfered with numerous protein expressions associated with neuronal support and myelination.
2017-12-02 | GSE107582 | GEO