| First Author | Li C | Year | 2024 |
| Journal | Cell Death Dis | Volume | 15 |
| Issue | 11 | Pages | 815 |
| PubMed ID | 39528445 | Mgi Jnum | J:358423 |
| Mgi Id | MGI:7780470 | Doi | 10.1038/s41419-024-07218-z |
| Citation | Li C, et al. (2024) GNG5 is a novel regulator of Abeta42 production in Alzheimer's disease. Cell Death Dis 15(11):815 |
| abstractText | The therapeutic options for Alzheimer's disease (AD) are limited, underscoring the critical need for finding an effective regulator of Abeta42 production. In this study, with 489 human postmortem brains, we revealed that homotrimer G protein subunit gamma 5 (GNG5) expression is upregulated in the hippocampal-entorhinal region of pathological AD compared with normal controls, and is positively correlated with Abeta pathology. In vivo and in vitro experiments confirm that increased GNG5 significantly promotes Abeta pathology and Abeta42 production. Mechanically, GNG5 regulates the cleavage preference of gamma-secretase towards Abeta42 by directly interacting with the gamma-secretase catalytic subunit presenilin 1 (PS1). Moreover, excessive GNG5 increases the protein levels and the activation of Rab5, leading to the increased number of early endosomes, the major cellular organelle for production of Abeta42. Furthermore, immunoprecipitation and immunofluorescence revealed co-interaction of Abeta42 with GPCR family CXCR2, which is known as the receptor for IL-8, thus facilitating the dissociation of G-proteins betagamma from alpha subunits. Treatment of Abeta42 in neurons combined with structure prediction indicated Abeta42 oligomers as a new ligand of CXCR2, upregulating gamma subunit GNG5 protein levels. The co-localizations of GNG5 and PS1, CXCR2 and Abeta42 were verified in eight human brain regions. Besides, GNG5 is significantly reduced in extracellular vesicles (EVs) derived from cerebral cortex or serum of AD patients compared with healthy cognition controls. In brief, GNG5 is a novel regulator of Abeta42 production, suggesting its clinical potential as a diagnosis biomarker and the therapeutic target for AD. The GNG5 content in EVs derived from serum and brain tissue of patients with AD significantly reduced. The GNG5 expression in the hippocampal-entorhinal neurons of donors with pathological AD significantly increased, and can exist in homotrimer subtypes. GNG5 expression positively correlates with Abeta pathology and Abeta42 production. Homotrimer-GNG5 binds to the gamma-secretase catalytic subunit PS1 and preferentially generates Abeta42 in early endosome. GNG5 leads to enhanced Rab5 protein and activation levels, increased number of early endosome, promoting Abeta42 production. Further, Abeta42 binds to CXCR2 to upregulate GNG5 levels in a feedback loop. |
