Delayed graft function (DGF) affects 25–30% of kidney transplant recipients and often requires dialysis within the first week post-surgery, highlighting a major unmet clinical need. Current immunosuppressive therapies fail to address the underlying driver of injury—necroptosis, a regulated cell death pathway that drives tubular damage and graft dysfunction. Necroptosis is mediated by activation of RIPK1, but most approaches target this pathway downstream and lack selectivity.
Emerging evidence shows that the PPP1R3G/PP1γ complex acts upstream by regulating RIPK1 activation, serving as a control point for initiating necroptotic cell death. This positions PPP1R3G/PP1γ as a novel and differentiated intervention target with the potential to block the pathway earlier and more selectively to prevent graft injury.
USF researchers have developed a peptidomimetic approach to inhibit the PPP1R3G/PP1γ interaction and directly block upstream necroptosis signaling. In preclinical studies, genetic disruption of PPP1R3G significantly reduced tubular cell death and suppressed key necroptosis markers, translating in vivo to ~50% reductions in graft injury and >50% improvements in kidney function following transplantation. Importantly, the lead therapeutic candidate, PGB‑1, demonstrated strong translational potential, achieving ~65% reductions in plasma creatinine and markedly decreasing tissue damage in transplant models. Together, these data validate PPP1R3G/PP1γ as a druggable target and position this technology as a differentiated, disease‑modifying strategy for preventing graft dysfunction.