Endothelial γ-protocadherins inhibit KLF2 and KLF4 to promote atherosclerosis

Endothelial Krüppel-like factor 2/4: Regulation and function in cardiovascular diseases

This review presents an overview of the regulation, function, disease-relevance and pharmacological regulation of the critical endothelial transcription factors KLF2/4 in vasculature. The regulatory mechanisms of KLF2/4 expression and activity in vascular endothelium in response to hemodynamic forces and biochemical stimuli are depicted. The functional effects mediated by direct or indirect target genes of KLF2/4 in endothelial cells are systematically summarized. The contributory roles that dysregulated KLF2/4 play in relevant cardiovascular pathologies, such as atherosclerotic vascular lesions, pulmonary arterial hypertension and vascular complications of diabetes were reviewed. Moreover, this review also discusses the pharmacological regulation of KLF2/4 by drugs used in clinics and therapeutic possibility by directly targeting these two transcription factors for treating atherosclerotic cardiovascular diseases. Finally, prospective opinions on the gaps in disclosing novel vascular function mediated by KLF2/4 and future research needs are expressed.

Fluid Shear Stress-Regulated Vascular Remodeling: Past, Present, and Future

The vascular system remodels throughout life to ensure adequate perfusion of tissues as they grow, regress, or change metabolic activity. Angiogenesis, the sprouting of new blood vessels to expand the capillary network, versus regression, in which endothelial cells die or migrate away to remove unneeded capillaries, controls capillary density. In addition, upstream arteries adjust their diameters to optimize blood flow to downstream vascular beds, which is controlled primarily by vascular endothelial cells sensing fluid shear stress (FSS) from blood flow. Changes in capillary density and small artery tone lead to changes in the resistance of the vascular bed, which leads to decreased or increased flow through the arteries that feed these small vessels. The resultant changes in FSS through these vessels then stimulate their inward or outward remodeling, respectively. This review summarizes our knowledge of endothelial FSS-dependent vascular remodeling, offering insights into potential therapeutic interventions. We first provide a historical overview, then discuss the concept of set point and mechanisms of low-FSS-mediated and high-FSS-mediated inward and outward remodeling. We then cover in vivo animal models, molecular mechanisms, and clinical implications. Understanding the mechanisms underlying physiological endothelial FSS-mediated vascular remodeling and their failure due to mutations or chronic inflammatory and metabolic stresses may lead to new therapeutic strategies to prevent or treat vascular diseases.

Glycometabolic Regulation of Angiogenesis: Mechanisms and Therapeutic Strategies

Angiogenesis, the process by which new blood vessels emerge from pre-existing vasculature, forms the fundamental biological basis for therapeutic angiogenesis. In recent years, this field has garnered significant attention, particularly in the context of understanding the mechanisms of angiogenesis through the lens of glycometabolism. The potential clinical applications of this research have been widely acknowledged within the medical community. In this article, the role of angiogenesis and the principal molecular mechanisms that govern it are first delineated. The influence of glycometabolism on angiogenesis is then explored, with a focus on glycolysis. Finally, research on therapeutic angiogenesis based on the regulation of glycometabolism is presented, offering novel perspectives for ongoing research and clinical applications.

Polycomb Repressive Complex 2 promotes atherosclerotic plaque vulnerability

Atherosclerotic cardiovascular disease (ASCVD), the leading cause of mortality worldwide, is driven by endothelial cell inflammatory activation and counter-balanced by anti-inflammatory transcription factors Klf2 and Klf4 (Klf2/4). Understanding vascular endothelial inflammation to develop effective treatments is thus essential. Here, we identify, Polycomb Repressive Complex (PRC) 2, which blocks gene transcription by trimethylating histone3 Lysine27 in gene promoter/enhancers, as a potent, therapeutically targetable determinant of vascular inflammation and ASCVD progression. Bioinformatics identified PRC2 as a direct suppressor of Klf2/4 transcription. Klf2/4 transcription requires Notch signaling, which reverses PRC2 modification of Klf2/4 promoter/enhancers. PRC2 activity is elevated in human ASCVD endothelium. Treating mice with established ASCVD with tazemetostat, an FDA approved pharmacological inhibitor of PRC2, slowed plaque progression by 50% and drastically improved markers of plaque stability. This study elucidates a fundamental mechanism of vascular inflammation, thus identifying a potential method for treating ASCVD and possibly other vascular inflammatory diseases.

Saving KLF2/4 from γ-protocadherin to reduce vascular inflammation and atherosclerosis

Atherosclerosis occurs in arterial regions exposed to disturbed flow, where endothelial expression of flow-sensitive, atheroprotective genes such as KLF2 and KLF4 is reduced. Protecting the endothelial expression of KLF2 and KLF4 from inhibitory factors could be a therapeutic approach to prevent vascular inflammation and atherosclerosis.