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Objectives: Intra-abdominal sepsis is commonly diagnosed in the surgical population and remains the second most common cause of sepsis overall. Sepsis-related mortality remains a significant burden in the intensive care unit despite advances in critical care. Nearly a quarter of the deaths in people with heart failure are caused by sepsis. We have observed that overexpression of mammalian Pellino-1 (Peli1), an E3 ubiquitin ligase, causes inhibition of apoptosis, oxidative stress, and preservation of cardiac function in a myocardial infarction model. Given these manifold applications, we investigated the role of Peli1 in sepsis using transgenic and knockout mouse models specific to this protein. Therefore, we aimed to explore further the myocardial dysfunction seen in sepsis through its relation to the Peli 1 protein by using the loss of function and gain-of-function strategy. Methods: A series of genetic animals were created to understand the role of Peli1 in sepsis and the preservation of heart function. Wild-type, global Peli1 knock out (Peli1−/−), cardiomyocyte-specific Peli1 deletion (CP1KO), and cardiomyocyte-specific Peli1 overexpressing (alpha MHC (αMHC) Peli1; AMPEL1Tg/+) animals were divided into sham and cecal ligation and puncture (CLP) surgical procedure groups. Cardiac function was determined by two-dimensional echocardiography pre-surgery and at 6- and 24-h post-surgery. Serum IL-6 and TNF-alpha levels (ELISA) (6 h), cardiac apoptosis (TUNEL assay), and Bax expression (24 h) post-surgery were measured. Results are expressed as mean ± S.E.M. Results: AMPEL1Tg/+ prevents sepsis-induced cardiac dysfunction assessed by echocardiographic analysis, whereas global and cardiomyocyte-specific deletion of Peli1 shows significant deterioration of cardiac functions. Cardiac function was similar across the sham groups in all three genetically modified mice. ELISA assay displayed how Peli 1 overexpression decreased cardo-suppressive circulating inflammatory cytokines (TNF-alpha, IL-6) compared to both the knockout groups. The proportion of TUNEL-positive cells varied according to Peli1 expression, with overexpression (AMPEL1Tg/+) leading to a significant reduction and Peli1 gene knockout (Peli1−/− and CP1KO) leading to a significant increase in their presence. A similar trend was also observed with Bax protein expression. The improved cellular survival associated with Peli1 overexpression was again shown with the reduction of oxidative stress marker 4-Hydroxy-2-Nonenal (4-HNE). Conclusion: Our results indicate that overexpression of Peli1 is a novel approach that not only preserved cardiac function but reduced inflammatory markers and apoptosis following severe sepsis in a murine genetic model.

Background: Our earlier studies showed that inhibiting prolyl-4-hydroxylase enzymes (PHD-1 and PHD-3) improves angiogenesis, heart function, and limb perfusion in mouse models via stabilizing hypoxia-inducible transcription factor-alpha (HIF-1α). The present study explored the effects of the prolyl-4-hydroxylase enzyme, PHD-2, on ischemic heart failure using cardiac-specific PHD-2 gene knockout (KO) mice (PHD2 -/- ).Study Design: Adult wild-type (WT) and PHD2 -/- mice, 8-12 weeks old, were subjected to myocardial infarction (MI) by irreversibly ligating the left anterior descending (LAD) coronary artery. All sham group mice underwent surgery without LAD ligation. Animals were divided into 4 groups: (1) wild-type sham (WTS); (2) wild-type myocardial infarction (WTMI); (3) PHD2KO sham (PHD2 -/- S); (4) PHD2KO myocardial infarction (PHD2 -/- MI). Left ventricular tissue samples collected at various time points after surgery were used for microRNA expression profiling, Western blotting, and immunohistochemical analysis.Results: Volcano plot analysis revealed 19 differentially-expressed miRNAs in the PHD2 -/- MI group compared with the WTMI group. Target analysis using Ingenuity Pathway Analysis showed several differentially regulated miRNAs targeting key signaling pathways such as Akt, VEGF, Ang-1, PTEN, apoptosis, and hypoxia pathways. Western blot analysis showed increased HIF-1α, VEGF, phospho-AKT, β-catenin expression and reduced Bax expression for the PHD2 -/- MI group compared with the WTMI group. Echocardiographic analysis showed preserved heart functions, and picrosirius red staining revealed decreased fibrosis in PHD2 -/- MI compared with the WTMI group.Conclusions: PHD2 inhibition showed preserved heart function, enhanced angiogenic factor expression, and decreased apoptotic markers after MI. Overall, cardiac PHD2 gene inhibition is a promising candidate for managing cardiovascular diseases. [ABSTRACT FROM AUTHOR]