Matrix Stiffness Triggers Metabolic Reprogramming in AKI Repair

Background: Effective kidney repair after AKI depends on a precisely regulated extracellular matrix (ECM) that offers both structural support and biomechanical cues. As key ECM producers, fibroblasts and pericytes are rapidly recruited to sites of tubular injury to facilitate repair. However, the composition of the kidney ECM proteome in AKI and the mechanisms by which the ECM orchestrates repair remain poorly understood. Methods: Decellularized kidney matrix scaffolds were isolated after AKI and subjected to proteomic profiling. A combination of genetic and pharmacological animal models, data-independent acquisition-based global and phosphoproteomics, spatial transcriptomics, tissue engineering, and ex vivo/in vitro systems was employed. Results: We profiled the proteome landscape of decellularized kidney matrix scaffold post-AKI and highlighted microfibrillar-associated protein 2 (Mfap2) as a key core matrisome component. Predominantly derived from fibroblasts and pericytes, Mfap2 deficiency disrupts renal architecture, ECM stiffness, and metabolic homeostasis, aggravating AKI. Global proteomics identified reduced expression of tubule-derived 3-hydroxy-3-methylglutaryl-CoA synthase 2 (Hmgcs2) in Mfap2 knockout kidneys, linked to estrogen receptor 2 (Esr2)-mediated transcriptional repression and elevated post-translational succinylation. Phosphoproteomics further revealed altered mechanotransduction, with Mfap2 deficiency hyperactivating mitogen-activated protein kinases, which in turn activated large tumor suppressor kinase 1 (Lats1) in tubular cells without changing integrin receptor activity. While Lats1 is a core kinase in the Hippo pathway, its activation here operated independently of Yap/Taz, instead augmenting Esr2 transcription without stabilizing its protein, as ubiquitination and proteasomal degradation remained unchanged. Administration of Esr2 agonists restored kidney function in Mfap2-deficient mouse models. Findings were validated in ex vivo and in vitro systems. Conclusion: Mfap2 is a central ECM regulator that links biomechanical signaling to metabolic reprogramming, orchestrating a pro-reparative microenvironment essential for kidney repair after AKI. Funding: NIDDK Support