Zingarelli, B. | Search bioRxiv

bioRxiv2025

Mortality Risk-Stratified Septic Serum Depresses Contractility and Mitochondrial Function in Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes

BackgroundSepsis-associated myocardial dysfunction (SAMD) is common in children with septic shock, is independently associated with mortality, and has no disease-modifying treatments. Differences in murine cardiomyocyte biology and repeated failures to translate discoveries into novel therapies for septic shock underscore a key translational need for human-relevant disease modeling. We sought to investigate human induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) exposed to mortality risk-stratified septic serum as a model of SAMD. MethodsSerum from children with septic shock (n=120) was stratified by Pediatric Sepsis Biomarker Risk Model (PERSEVERE) II mortality probability as low, intermediate, or high risk. We conducted aptamer-based proteomic analysis of septic serum to determine differentially expressed proteins in children with high compared to low mortality risk. We treated iPSC-CMs with risk-stratified septic serum and defined contractile and mitochondrial functional and transcriptomic responses. ResultsWe found 612 differentially expressed proteins in children with high mortality probability, most prominently interleukins (IL)-6 and -8. High-risk septic serum reversibly depressed iPSC-CM contractility as measured by percent shortening, while low-risk septic serum had no impact. Further, high-risk septic serum depressed basal mitochondrial respiration, maximum uncoupled respiration, and coupled oxidative phosphorylation in iPSC-CMs relative to low-risk serum. We identified distinct patterns of gene expression due to risk-stratified serum with 5,293 differentially expressed genes, including upregulation of acute phase reactants and apolipoproteins and downregulation of chemokines, as well as transcriptional changes reflective of chronic IL-6 and IL-8 signaling. ConclusionsSeptic serum from children with high mortality risk exhibited distinct proteomic signatures, notably enriched for IL-6 and IL-8. Human iPSC-CMs differentially responded to risk-stratified septic serum, recapitulating phenotypic features of SAMD including reversible contractility depression and mitochondrial dysfunction with high-risk septic serum. These findings establish mortality risk-stratified septic serum exposure of iPSC-CMs as a human-relevant translational platform to interrogate mechanisms of myocardial dysfunction in septic shock.

immunology↗

bioRxiv2024

KF4 anti-CELA1 Antibody and Purified α1-Antitrypsin Have Similar but Not Additive Efficacy in Preventing Emphysema in Murine α1-Antitrypsin Deficiency

Alpha-1 antitrypsin (AAT) deficiency is the most common genetic cause of emphysema. Chymotrypsin-like Elastase 1 (CELA1) is a serine protease neutralized by AAT and is important in emphysema progression. Cela1-deficiency is protective in a murine models of AAT-deficient emphysema. KF4 anti-CELA1 antibody prevented emphysema in PPE and cigarette smoke models in wild type mice. We evaluated potential toxicities of KF4 and its ability to prevent emphysema in AAT deficiency. We found Cela1 protein expression in mouse lung, pancreas, small intestine, and spleen. In toxicity studies, mice treated with KF4 25 mg/kg weekly for four weeks showed an elevation in blood urea nitrogen and slower weight gain compared to lower doses or equivalent dose IgG. In histologic grading of tissue injury of the lung, kidney, liver, and heart, there was some evidence of liver injury with KF4 25 mg/kg, but in all tissues, injury was less than in control mice subjected to cecal ligation and puncture. In efficacy studies, KF4 doses as low as 0.5 mg/kg reduced the lung elastase activity of AAT-/-mice treated with 0.2 units of PPE. In this injury model, AAT-/-mice treated with KF4 1 mg/kg weekly, human purified AAT 60 mg/kg weekly, and combined KF4 and AAT treatment had less emphysema than mice treated with IgG 1 mg/kg weekly. However, the efficacy of KF4, AAT, or KF4 & AAT was similar. While KF4 might be an alternative to AAT replacement, combined KF4 and AAT replacement does not confer additional benefit.

pathology↗