Zeguo Sun | Search PubMed

PubMed2025

Design of precision therapeutics for a CKD risk allele by targeting Shroom3-Rock interaction.

Enhancer variants in Shroom3 associate with renal fibrosis (TIF), but with reduced albuminuria. Detailed mechanisms for these pleiotropic effects are unclear. Here, we focus on identifying the specific profibrotic Shroom3 motif and separating this from its anti-proteinuric function. Given the role for Rho-kinases (Rock) in TIF, and the interaction of Rock with Shroom3 ASD2-domain, we hypothesized that Shroom3-mediated Rock-activation is crucial for profibrotic function. To test this, we develop transgenic tools that overexpress wild-type- (WT-Sh3) or ASD2-domain deletion- Shroom3 (ASD2Δ-Sh3). During TIF, Shroom3 and Rock co-expression occur in injured tubular cells and fibroblasts. In tubular- & fibroblast- lines, ASD2Δ-Sh3 overexpression reduce Rock activation, and pro-fibrotic/pro-inflammatory transcripts downstream of TGFβ1/Wnt/Ctnnb1-signaling vs WT-Sh3. In vivo, inducible global-, or tubular-specific-, but not fibroblast-specific-, ASD2Δ-Sh3 overexpression mitigate TIF, vs WT-Sh3 overexpression. Importantly, ASD2Δ-Sh3 mice do not develop albuminuria, while overexpression of a distinct Fyn-binding deficient mutant Shroom3 (FBDM-Sh3) induces albuminuria. We then develop small molecule inhibitors of Shroom3-Rock interaction (P2Is) and confirm Rock inhibition with these agents in WT-Sh3 cell lines. Our lead P2I from these studies, BT1137, mitigates Rock-activation, profibrotic signaling and TIF in WT-Sh3 mice. Hence, we delineate the profibrotic Shroom3 motif and develop therapeutics for kidney disease from Shroom3 excess.

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PubMed2025

Liquid Biopsy-Multiomics Link Adhesion Pathway Dysregulation to Kidney Injury Severity.

INTRODUCTION: Severe acute kidney injury (AKI) is strongly associated with the risk of developing chronic kidney disease; however, little is known about the cell type-specific mechanisms driving kidney injury severity. METHODS: In this multicenter observational study, we used clinically obtained liquid biopsy proteomics and machine learning (ML) to predict severe outcomes in patients with COVID-associated and non-COVID AKI. Further, we orthogonally combined 169 urine proteomics with 437 plasma proteomics samples and 40 urine sediment single-cell transcriptomics samples to identify complementary dysregulated mechanisms. RESULTS: Using a 10-fold cross-validated random forest algorithm, we identified a set of urinary proteins that demonstrate predictive power for both discovery and validation set with AUC of 87% and 76%, respectively. These predictive proteomics features obtained demonstrate that cell adhesion and autophagy-associated pathways are uniquely impacted in severe AKI. Differentially abundant proteins (DAPSs) associated with these pathways are highly expressed in cells of the juxtamedullary nephron, endothelial cells (ECs), and podocytes, indicating that these kidney cell types could be potential targets. Single-cell transcriptomic analysis in the in vitro model of kidney organoids infected with SARS-CoV-2 reveal dysregulation of extracellular matrix (ECM) organization in multiple nephron segments, recapitulating the clinically observed fibrotic response across multiomics datasets. Ligand-receptor interaction analysis of the podocyte and tubule organoid clusters shows significant reduction and loss of interaction between integrins and basement membrane receptors in the infected kidney organoids. CONCLUSION: Collectively, these data suggest that ECM degradation and adhesion-associated mechanisms could be the main driver of severe kidney injury.

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