Endothelial Forkhead Box Transcription Factor P1 Regulates Pathological Cardiac Remodeling Through Transforming Growth Factor-β1–Endothelin-1 Signal Pathway

Abstract

Background: Pathological cardiac fibrosis and hypertrophy, the common features of left ventricular remodeling, often progress to heart failure. Forkhead box transcription factor P1 (Foxp1) in endothelial cells (ECs) has been shown to play an important role in heart development. However, the effect of EC-Foxp1 on pathological cardiac remodeling has not been well clarified. This study aims to determine the role of EC-Foxp1 in pathological cardiac remodeling and the underlying mechanisms. Methods: Foxp1 EC-specific loss-of-function and gain-of-function mice were generated, and an angiotensin II infusion or a transverse aortic constriction operation mouse model was used to study the cardiac remodeling mechanisms. Foxp1 downstream target gene transforming growth factor-β1 (TGF-β1) was confirmed by chromatin immunoprecipitation and luciferase assays. Finally, the effects of TGF-β1 blockade on EC-Foxp1 deletion–mediated profibrotic and prohypertrophic phenotypic changes were further confirmed by pharmacological inhibition, more specifically by RGD-peptide magnetic nanoparticle target delivery of TGF-β1–siRNA to ECs. Results: Foxp1 expression is significantly downregulated in cardiac ECs during angiotensin II–induced cardiac remodeling. EC-Foxp1 deletion results in severe cardiac remodeling, including more cardiac fibrosis with myofibroblast formation and extracellular matrix protein production, as well as decompensated cardiac hypertrophy and further exacerbation of cardiac dysfunction on angiotensin II infusion or transverse aortic constriction operation. In contrast, EC-Foxp1 gain of function protects against pathological cardiac remodeling and improves cardiac dysfunction. TGF-β1 signals are identified as Foxp1 direct target genes, and EC-Foxp1 deletion upregulates TGF-β1 signals to promote myofibroblast formation through fibroblast proliferation and transformation, resulting in severe cardiac fibrosis. Moreover, EC-Foxp1 deletion enhances TGF-β1–promoted endothelin-1 expression, which significantly increases cardiomyocyte size and reactivates cardiac fetal genes, leading to pathological cardiac hypertrophy. Correspondingly, these EC-Foxp1 deletion–mediated profibrotic and prohypertrophic phenotypic changes and cardiac dysfunction are normalized by the blockade of TGF-β1 signals through pharmacological inhibition and RGD-peptide magnetic nanoparticle target delivery of TGF-β1–siRNA to ECs. Conclusions: EC-Foxp1 regulates the TGF-β1–endothelin-1 pathway to control pathological cardiac fibrosis and hypertrophy, resulting in cardiac dysfunction. Therefore, targeting the EC–Foxp1–TGF-β1–endothelin-1 pathway might provide a future novel therapy for heart failure.

Therapeutic silencing miR-146b-5p improves cardiac remodeling in a porcine model of myocardial infarction by modulating the wound reparative phenotype

“…CMVECs play a vital role in the regulation of fibrotic remodeling (Liu et al, 2019). Previous work found that miR-146 represses endothelial cell activity by targeting endothelial nitric oxide synthase in response to stimulation by the pro-inflammatory cytokine IL-1β (Cheng et al, 2013).…”

Cardiovascular Changes Associated with Hypertensive Heart Disease and Aging

“…Various hemodynamic, structural, neuroendocrine, cellular, and molecular factors play integral roles in the development of hypertension and associated abnormalities. Abnormalities in the renin–angiotensin–aldosterone system and sympathetic nervous system, endothelial dysfunction, and vascular inflammation can independently contribute to hypertension 3 , 4 , 7 , 8 . Also oxidative stress that develops in the early stages of hypertension results in further release of reactive oxygen species (ROS), contributing to hypertension-induced irregularities 9 .…”

“…The fibrillar collagen provides structural integrity to adjoining myocytes and aids in myocyte contraction that translates into efficient cardiac contraction 24 . Pathological hypertrophy is associated with increased interstitial and perivascular fibrosis 4 . Myocyte loss due to apoptosis and necrosis is replaced by collagen deposition.…”

“…Many physiological, cellular, and molecular mechanisms have been proposed to explain the transition from hypertrophy to failure. The pathological changes of the heart in patients with LVH include an increase in the size of the cardiomyocyte, alterations in the extracellular matrix (ECM) with accumulation of collagen and fibrosis, and abnormalities of the intramyocardial coronary vasculature 2 – 4 . The neurohormones, growth factors, and cytokines also influence the progression of hypertrophy.…”

Recombinant Cellular Repressor of E1A-Stimulated Genes Protects against Renal Fibrosis in Dahl Salt-Sensitive Rats

“…Real-time PCR was performed on an ABI 7300 PCR System. Primer sequences for CREG, GAPDH, TGF-β1, and forkhead box P1 (Foxp1) [13] are listed in online supplementary Table 2.…”