Cell-Targeted Inhibition of CaMK4 Suppresses Tertiary Lymphoid-like Structure Development in Lupus-Prone Mice

Current treatment of lupus nephritis (LN) relies on broad immunosuppression and often fails to eradicate intrarenal immune niches that sustain inflammation. Tertiary lymphoid structures (TLS)—organized aggregates of immune cells forming in chronically inflamed non-lymphoid tissues—are increasingly recognized as drivers of local immune activation and tissue injury in LN. We previously showed that genetic CaMK4 deficiency suppresses autoimmunity and nephritis in lupus-prone mice. Here, we tested whether CaMK4 regulates renal TLS-like organization. Using kidneys from MRL/lpr mice that were CaMK4-deficient or treated with KN93-loaded nanoparticles targeted to CD4+ T cells or podocytes (anti-podocin), we compared findings with vehicle-treated controls. TLS-associated inflammation and maturation were quantified by mean fluorescence intensity of CD3, CD20, Ki67, and α-SMA. Across genetic and targeted-treatment arms, CaMK4 inhibition reduced all assessed markers, with uniform suppression of CD20 signal, highlighting a key role for B cells in TLS maintenance. Notably, podocyte-targeted KN93 most strongly suppressed TLS-like formation, implicating podocyte-driven pathways in interstitial inflammation and lymphoid neogenesis through previously underappreciated mechanisms. These data identify CaMK4 as a regulator of TLS-like architecture in LN and support the translational potential of cell-targeted CaMK4 inhibition to disrupt local immune recruitment while limiting systemic toxicity.