Single-cell Transcriptomics Reveals that the SORBS1/FBXO22/BAG3 Axis Drives Astrocyte Senescence via Calcium Signaling and Affects Alzheimer's Disease-Related Neuronal Damage.

Authors

Yan Li, Xindong He

Published in

Neuromolecular medicine. Volume 28. Issue 1. Jun 17, 2026. Epub Jun 17, 2026.

Abstract

In Alzheimer's disease (AD), senescent astrocytes fuel neuroinflammation and neuronal damage via the senescence-associated secretory phenotype (SASP). Calcium signaling plays a crucial role in this process, but the underlying molecular mechanisms remain elusive. We retrieved scRNA-seq data from the Gene Expression Omnibus (GEO) for AD and control brains. After cell-type annotation, we resolved astrocyte sub-clusters. Pseudotime trajectory and differential-expression analyses identified SORBS1 as a key senescence-related gene, which we followed with gene-set enrichment analysis. Next, we established an in vitro AD model by treating astrocytes with amyloid-β (Aβ). We evaluated astrocyte senescence using SA-β-gal staining, qRT-PCR, Western blot (WB) for senescence markers, and ELISA for SASP cytokines. We measured concentration of Ca²⁺ with Fluo-4 AM probes. Subsequently, bioinformatic screening predicted FBXO22 as an interactor of SORBS1 and BAG3 as a ubiquitination substrate of FBXO22. We validated these interactions using Co-IP and in vitro ubiquitination assays. Finally, we constructed an astrocyte-neuron co-culture model. We detected neuronal cell viability, AChE activity, AD phenotype-related protein expression, apoptosis, and levels of inflammatory factors using MTT assay, specific kits, WB, flow cytometry, and ELISA, respectively, to assess neuronal damage. ScRNA-seq analysis revealed a marked reduction in astrocyte expression in AD brains, which may result from cellular senescence. The SASP gene SORBS1 was selectively up-regulated in astrocytes and significantly enriched in calcium-signaling pathways. Functional assays confirmed that SORBS1 accelerated astrocyte senescence. Mechanistically, SORBS1 interacted with FBXO22 to promote the ubiquitin-dependent degradation of BAG3, thereby amplifying calcium signaling, accelerating astrocyte senescence, and contributing to AD-related neuronal damage. We uncover a novel mechanism by which the SORBS1/FBXO22/BAG3 axis drives astrocyte senescence through the regulation of calcium signaling, thereby influencing AD-related neuronal damage. This finding provides a potential therapeutic target for AD treatment by targeting astrocyte senescence.

PMID:
42307825
Bibliographic data and abstract were imported from PubMed on 17 Jun 2026.

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