Redox DAPK1 destabilizes Pellino1 to govern inflammation-coupling tubular damage during septic AKI.
Tubular damage initiated by inflammatory response and ischemic/hypoxic stress is a hallmark of septic acute kidney injury (AKI), albeit the molecular mechanism coupling the two events remains unclear. We investigated the intrinsic nature of tubular damage with respect to inflammatory/hypoxic stress during septic AKI. Methods: The apoptotic response of tubular ... cells to LPS stimuli was analyzed before and after hypoxia exposure. Cellular ubiquitination, co-immunoprecipitation, GST-pulldown, in vitro protein kinase assay, immunofluorescence and CRISPR technology were adopted to determine the molecular mechanism underlying this process. In vivo characterization was performed in wild-type and DAPK1-/- mice models of cecal ligation and puncture (CLP). Results: We found that the MyD88-dependent inflammatory response couples to tubular damage during LPS stimuli under hypoxia in a Fn14/SCFFbxw7?-dispensable manner via recruitment of caspase-8 with TRIF-RIP1 signalosome mediated by DAPK1, which directly binds to and phosphorylates Pellino1 at Ser39, leading to Pellino1 poly-ubiquitination and turnover. Either pharmacological deactivation or genetic ablation of DAPK1 makes tubular cells refractory to the LPS-induced damage in the context of hypoxia, while kinase activity of DAPK1 is essential for ruin execution. Targeting DAPK1 effectively protects mice against septic AKI and potentiates the efficacy of a MyD88 homodimerization inhibitor, ST2825. Conclusion: Our findings provide a rationale for the mechanism whereby inflammation intersects with hypoxic tubular damage during septic AKI through a previously unappreciated role of DAPK1-inducible Ser39 phosphorylation in Pellino1 turnover and underscore that combined targeting DAPK1 and MyD88 might be a feasible strategy for septic AKI management.
Mesh Terms:
Acute Kidney Injury, Animals, CRISPR-Cas Systems, Cell Hypoxia, Cell Line, Death-Associated Protein Kinases, Disease Models, Animal, Epithelial Cells, Gene Knockout Techniques, Heterocyclic Compounds, 2-Ring, Humans, Kidney Tubules, Mice, Mice, Knockout, Myeloid Differentiation Factor 88, Nuclear Proteins, Oxidation-Reduction, Phosphorylation, RAW 264.7 Cells, Sepsis, Spiro Compounds, Ubiquitin-Protein Ligases, Ubiquitination
Acute Kidney Injury, Animals, CRISPR-Cas Systems, Cell Hypoxia, Cell Line, Death-Associated Protein Kinases, Disease Models, Animal, Epithelial Cells, Gene Knockout Techniques, Heterocyclic Compounds, 2-Ring, Humans, Kidney Tubules, Mice, Mice, Knockout, Myeloid Differentiation Factor 88, Nuclear Proteins, Oxidation-Reduction, Phosphorylation, RAW 264.7 Cells, Sepsis, Spiro Compounds, Ubiquitin-Protein Ligases, Ubiquitination
Theranostics
Date: Oct. 15, 2020
PubMed ID: 33052227
View in: Pubmed Google Scholar
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