Inhibitors of KAT2A Alleviate the Progression of AKI by Alleviating Macrophage Ferritinophagy.

Abstract

Background: Acute kidney injury (AKI) involves complex inflammatory responses in which macrophage dysfunction plays a central role. Although histone acetyltransferase KAT2A has been implicated in immune regulation, its role in macrophage ferritinophagy during AKI remains unclear.

Methods: Single-cell RNA sequencing analysis of mouse kidney tissue identified abnormal activation of ferritinophagy and upregulation of KAT2A in renal macrophage during AKI progression. Colocalization of FTH1 and LAMP1 and the increased fluorescence intensity of FTH1 and NCOA4 proteins, and KAT2A proteins in macrophage of kidney in AKI samples were detected via immunofluorescence staining. Functional impacts of KAT2A on macrophage ferritinophagy were assessed using KAT2A knockdown and overexpression plasmids in RAW264.7 cell lines. Butyrolactone 3 (MB-3), a specific KAT2A inhibitor, was administered via intraperitoneal injection 24 hours post-IR to assess the influence of MB-3 on renal pathological changes and the activity of macrophage ferritinophagy.

Results: In this study, using single-cell RNA sequencing and dual immunofluorescence, we observed aberrant ferritinophagy in renal macrophages, marked by increased colocalization of FTH1 with LAMP1 and NCOA4, alongside elevated CD68 expression. KAT2A was upregulated in macrophages from both human AKI biopsies and murine models. Genetic knockdown of KAT2A suppressed ferritinophagy, reduced NCOA4 and FTH1 expression, decreased FTH1-LAMP1 colocalization, and inhibited cGAS signaling. Conversely, KAT2A overexpression exacerbated these processes. Critically, NCOA4 silencing abolished KAT2A-driven ferritinophagy and cGAS-STING activation. Pharmacological inhibition of KAT2A with MB-3 significantly attenuated renal injury, macrophage infiltration, and ferritinophagy, and reduced colocalization of KAT2A or NCOA4 with F4/80.

Conclusion: These findings demonstrate that KAT2A promotes AKI progression via NCOA4-mediated ferritinophagy and cGAS-STING inflammatory signaling in macrophages, highlighting KAT2A inhibition as a promising therapeutic strategy for AKI.