<p>Immunoglobulin A (IgA) nephropathy (IgAN) is characterized by the deposition of IgA1 in the glomerular mesangium, which induces secondary glomerular and tubulointerstitial inflammation and subsequently leads to podocyte apoptosis and fibrosis. This condition often progresses to end-stage renal disease and lacks effective targeted treatment. Our study aimed to explore the role of M2 macrophage-mediated Ubiquitin C-terminal hydrolase L1 (UCHL1) expression in podocytes and its potential impact on the progression of IgAN. This study established an IgAN cellular model by exposing podocytes to aggregated IgA1 (aIgA1)-treated glomerular mesangial cells supernatants and assessed the impact of M2 macrophage polarization on UCHL1 expression and podocyte apoptosis. Additionally, we utilized siRNA technology and overexpression constructs to investigate the direct effects of UCHL1 modulation on podocyte apoptosis. The supernatant from aIgA1-treated glomerular mesangial cells significantly induced apoptosis in podocytes. Based on this, M2 macrophage polarization was induced using interleukin (IL)-4. The results showed that M2 macrophages (CD163⁺) effectively alleviated podocyte apoptosis by reducing the secretion of inflammatory cytokines IL-6, tumor necrosis factor (TNF)-α, and IL-1β, as well as downregulating the expression of apoptosis-related proteins. Notably, M2 macrophages (CD163⁺) inhibited the expression of UCHL1 in podocytes. Blockade of UCHL1 promoted podocyte proliferation, reduced apoptosis, and downregulated the protein expression of the fibrotic markers vascular endothelial growth factor and collagen type IV. Overexpression of UCHL1 reversed the protective effects of M2 macrophages on podocyte apoptosis. M2 macrophage (CD163⁺)-mediated UCHL1 downregulation in podocytes presents a potential therapeutic approach for IgAN by alleviating apoptosis.</p>