Abstract
Introduction
Splenic senescence represents a hallmark of aging-related immune dysfunction, and the fungus
Kazachstania pintolopesii
is capable of aggravating senescence-associated phenotypes in aged mice. As a natural bioactive ingredient, Astragaloside IV (AGS) possesses anti-aging and immunomodulatory capacities, whereas its protective mechanisms against
K. pintolopesii
-triggered splenic senescence remain poorly defined. This study aimed to clarify the molecular mechanisms underlying
K. pintolopesii
-induced splenic senescence and validate the protective efficacy of AGS.
Methods
This study integrated
in vivo
interventions, multi-omics sequencing, comprehensive histopathological examination, multidimensional bioinformatics analysis, and cross-species conservation validation to systematically explore the pathogenic role of
K. pintolopesii
and the protective action of AGS. scRNA-seq and bulk RNA-seq were applied to profile splenic transcriptional alterations. Histopathological staining including H&E, Masson, Prussian blue, and IHC staining was performed to visualize splenic structural impairment, fibrosis, iron deposition, and target protein expression. Bioinformatics analyses containing UMAP dimensionality reduction, pseudotime trajectory analysis, DEG screening, and GO/KEGG functional enrichment were conducted to dissect key molecular pathways.
Results
The results showed that
K. pintolopesii
induced characteristic splenic structural changes in aged mice, including white pulp lymphocyte rarefaction, mild interstitial fibrosis, and prominent iron overload, accompanied by immune subset remodeling. Mechanistically, K. pintolopesii promoted the differentiation of naive T cells into effector/memory phenotypes, drove B cell polarization toward a pro-senescent marginal zone signature, and elicited myeloid cell reprogramming with activated ferroptosis. These pathological events originated from the synergistic crosstalk between ferro-aging (iron overload and ACSL4-mediated lipid peroxidation) and chronic inflammation. Moreover, AGS intervention significantly attenuated KP-associated pathological changes by restoring splenic immune function, modulating iron metabolism and redox homeostasis, suppressing ferroptosis/ferro-aging signaling, and disrupting the senescence-inflammation positive feedback loop.
Discussion
In conclusion,
K. pintolopesii
exacerbates splenic senescence in aged mice via the synergistic interaction between immune senescence and ferro-aging. AGS exerts protective effects on the spleen by targeting the iron-immune axis. This study demonstrates that AGS is a promising therapeutic candidate for the intervention of aging-associated splenic immune dysfunction, providing novel insights into the mechanism of fungal-induced splenic senescence and potential anti-aging therapeutic strategies.