Untangling the GDF15-NETosis Connection: Implications for Targeted Therapy in Diabetic Cardiomyopathy

Abstract

Background: Diabetic Cardiomyopathy (DCM) is a pathophysiological condition induced by diabetes mellitus and characterized by cardiomyocyte death, hypertrophy, and fibrosis. Diabetes-induced alterations in endothelial and cardiac muscle cells have been reported to be major causative factors in the onset and progression of DCM. An alteration in the expression of cardiac fibrosis markers has been identified as a consequence of DCM. Furthermore, accumulating evidence associates chronic hyperglycemia with oxidative stress as a pathway that facilitates DCM progression. There is increasing evidence for the expression of NOXs, particularly NOX4, in the heart, contributing to the pathogenesis of cardiac hypertrophy, fibrosis, inflammation, and progression towards heart failure (HF). Recently, NOX-generated reactive oxygen species (ROS) are proposed to mediate a neutrophil-specific cell death process known as NETosis which was found to be associated with diabetes, as neutrophils are the first responders and secrete neutrophil extracellular traps (NETs), which induce sustained inflammation. On the other hand, Growth Differentiating Factor 15 (GDF-15), a member of the transforming growth factor β (TGF β) cytokine superfamily that acts as a stress-responsive cytokine, and has been shown to regulate neutrophil arrest and counteract its recruitment. However, a direct correlation between GDF-15 and NETosis and the role of their crosstalk in diabetes-induced cardiovascular complications remains to be elucidated. Hypothesis: We hypothesize that GDF-15 inhibition using an AV-380 monoclonal antibody ameliorates diabetic cardiomyopathy by attenuating NETosis. We also inspect the influence of AV-380 on cardiac function, injury, fibrotic markers, and oxidative stress, particularly focusing on NOX4 and NADPH signaling. Materials and Methods: Two sets of animals were utilized to assess our hypothesis. C57BL/6J male mice were used in this experimental design. In the first animal model, they were divided into six groups: (1) Control mice receiving vehicle (saline), (2) Control mice receiving 7.5 mg/kg AV-380, (3) Control mice receiving 20 mg/kg AV-380, (4) type 2 diabetes mellitus (T2DM) mice receiving vehicle (saline), (5) T2DM mice treated with 7.5 mg/kg AV-380, and (6) T2DM mice treated with 20 mg/kg AV-380. The treatment duration was 8 weeks. T2DM was induced by five consecutive doses of 55 mg/kg streptozotocin (STZ) and fed a high-fat diet (HFD). This set of animals was followed by a similar animal model excluding Control mice receiving 7.5 mg/kg AV-380 or 20 mg/kg AV-380 and the duration of the treatment was extended to 15 weeks. Following sacrifice and organ harvest, functional, histopathological, and molecular analyses were performed on the left ventricle of all groups. Results: Our findings indicate that inhibiting GDF-15 with AV-380 can restore cardiovascular homeostasis in T2DM mice. This is evident through reduced proteinuria, decreased superoxide generation and NADPH oxidase activity, reduced IL-1β and IL-6 levels, as well as improved cardiac ejection fraction and fractional shortening in the treated diabetic mice. Interestingly, the inhibition of GDF-15 significantly reduced NETosis markers. Conclusion: Our findings highlight GDF-15 as a plausible therapeutic target in DCM, alleviating inflammation, oxidative stress, and structural malfunctions in the heart and restoring cardiovascular homeostasis. Further studies are warranted to clinically validate these findings and to assess the relevance of AV-380 as a novel therapeutic intervention for cardiovascular disorders.