Endothelial Ca2+ signaling-dependent vasodilation through transient receptor potential channels

Effects of SGLT2 inhibitors on ion channels in heart failure: focus on the endothelium

Heart failure (HF) is a life-threatening cardiovascular disease associated with high mortality, diminished quality of life, and a significant economic burden on both patients and society. The pathogenesis of HF is closely related to the endothelium, where endothelial ion channels play an important role in regulating intracellular Ca2+ signals. These ion channels are essential to maintain vascular function, including endothelium-dependent vascular tone, inflammation response, and oxidative stress. Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have shown promising cardiovascular benefits in HF patients, reducing mortality risk and hospitalization in several large clinical trials. Clinical and preclinical studies indicate that the cardioprotective effects of SGLT2i in HF are mediated by endothelial nitric oxide (NO) pathways, as well as by reducing inflammation and reactive oxygen species in cardiac endothelial cells. Additionally, SGLT2i may confer endothelial protection by lowering intracellular Ca2+ level through the inhibition of sodium-hydrogen exchanger 1 (NHE1) and sodium-calcium exchanger (NCX) in endothelial cells. In this review, we discuss present knowledge regarding the expression and role of Ca2+-related ion channels in endothelial cells in HF, focusing on the effects of SGLT2i on endothelial NHE1, NCX as well as on vascular tone.

The antioxidant property of CAPE depends on TRPV1 channel activation in microvascular endothelial cells

Caffeic acid phenethyl ester (CAPE) is a hydrophobic phytochemical typically found in propolis that acts as an antioxidant, anti-inflammatory and cardiovascular protector, among several other properties. However, the molecular entity responsible for recognising CAPE is unknown, and whether that molecular interaction is involved in developing an antioxidant response in the target cells remains an unanswered question. Herein, we hypothesized that a subfamily of TRP ion channels works as the molecular entity that recognizes CAPE at the plasma membrane and allows a fast shift in the antioxidant capacity of intact endothelial cells (EC). By monitoring cytoplasmic Ca2+ in a microvascular EC model, we compared the calcium responses evoked by three structurally related compounds: caffeic acid phenethyl ester, neochlorogenic acid and caffeic acid. Only CAPE induced rapid and transient calcium responses at nanomolar concentrations together with a gradual increase in cytoplasmic sodium levels, suggesting the activation of a non-selective cationic permeation at the plasma membrane. Electrophysiological as well as pharmacological, and RNA silencing assays confirmed the involvement of TRPV1 in the recognition of CAPE by ECs. Finally, we demonstrated that Ca2+ influx by TRPV1 was necessary for recording CAPE-induced cytoplasmic redox changes, a phenomenon captured in real-time in ECs expressing the HyPer biosensor. Our data depict a molecular mechanism behind the antioxidant effect of CAPE in endothelial cells, connecting the activation of TRPV1 ion channels, cytoplasmic calcium increase, and a reduction of disulfide bonds on a redox biosensor. This phenomenon occurs within seconds to minutes and contributes to a better understanding of the mechanisms underlying the vasodilatory effect of CAPE and other compounds that interact with TRPV1 in the vascular bed.

Role of TRP Channels in Metabolism-Related Diseases

Metabolic syndrome (MetS), with its high prevalence and significant impact on cardiovascular disease, poses a substantial threat to human health. The early identification of pathological abnormalities related to MetS and prevention of the risk of associated diseases is of paramount importance. Transient Receptor Potential (TRP) channels, a type of nonselective cation channel, are expressed in a variety of tissues and have been implicated in the onset and progression of numerous metabolism-related diseases. This study aims to review and discuss the expression and function of TRP channels in metabolism-related tissues and blood vessels, and to elucidate the interactions and mechanisms between TRP channels and metabolism-related diseases. A comprehensive literature search was conducted using keywords such as TRP channels, metabolic syndrome, pancreas, liver, oxidative stress, diabetes, hypertension, and atherosclerosis across various academic databases including PubMed, Google Scholar, Elsevier, Web of Science, and CNKI. Our review of the current research suggests that TRP channels may be involved in the development of metabolism-related diseases by regulating insulin secretion and release, lipid metabolism, vascular functional activity, oxidative stress, and inflammatory response. TRP channels, as nonselective cation channels, play pivotal roles in sensing various intra- and extracellular stimuli and regulating ion homeostasis by osmosis. They present potential new targets for the diagnosis or treatment of metabolism-related diseases.

The Dysfunction of Ca2+ Channels in Hereditary and Chronic Human Heart Diseases and Experimental Animal Models

Chronic heart diseases, such as coronary heart disease, heart failure, secondary arterial hypertension, and dilated and hypertrophic cardiomyopathies, are widespread and have a fairly high incidence of mortality and disability. Most of these diseases are characterized by cardiac arrhythmias, conduction, and contractility disorders. Additionally, interruption of the electrical activity of the heart, the appearance of extensive ectopic foci, and heart failure are all symptoms of a number of severe hereditary diseases. The molecular mechanisms leading to the development of heart diseases are associated with impaired permeability and excitability of cell membranes and are mainly caused by the dysfunction of cardiac Ca2+ channels. Over the past 50 years, more than 100 varieties of ion channels have been found in the cardiovascular cells. The relationship between the activity of these channels and cardiac pathology, as well as the general cellular biological function, has been intensively studied on several cell types and experimental animal models in vivo and in situ. In this review, I discuss the origin of genetic Ca2+ channelopathies of L- and T-type voltage-gated calcium channels in humans and the role of the non-genetic dysfunctions of Ca2+ channels of various types: L-, R-, and T-type voltage-gated calcium channels, RyR2, including Ca2+ permeable nonselective cation hyperpolarization-activated cyclic nucleotide-gated (HCN), and transient receptor potential (TRP) channels, in the development of cardiac pathology in humans, as well as various aspects of promising experimental studies of the dysfunctions of these channels performed on animal models or in vitro.

Skin Microhemodynamics and Mechanisms of Its Regulation in Type 2 Diabetes Mellitus

The review presents modern ideas about peripheral microhemodynamics, approaches to the ana-lysis of skin blood flow oscillations and their diagnostic significance. Disorders of skin microhemodynamics in type 2 diabetes mellitus (DM) and the possibility of their interpretation from the standpoint of external and internal interactions between systems of skin blood flow regulation, based on a comparison of couplings in normal and pathological conditions, including models of pathologies on animals, are considered. The factors and mechanisms of vasomotor regulation, among them receptors and signaling events in endothelial and smooth muscle cells considered as models of microvessels are discussed. Attention was drawn to the disturbance of Ca2+-dependent regulation of coupling between vascular cells and NO-dependent regulation of vasodilation in diabetes mellitus. The main mechanisms of insulin resistance in type 2 DM are considered to be a defect in the number of insulin receptors and impaired signal transduction from the receptor to phosphatidylinositol-3-kinase and downstream targets. Reactive oxygen species plays an important role in vascular dysfunction in hyperglycemia. It is assumed that the considered molecular and cellular mechanisms of microhemodynamics regulation are involved in the formation of skin blood flow oscillations. Parameters of skin blood microcirculation can be used as diagnostic and prognostic markers for assessing the state of the body.

Correlation of vascular change with TRPV1, TRPV4, and TRPA1 in a rat model of inferior gluteal artery perforator flap

Maximum survival area after perforator flap elevation is mainly achieved through vasodilation and angiogenesis, and endothelial Ca²⁺ signals play a pivotal role in both of them. Transient receptor potential (TRP) channels modulate many endothelial cell functions via mediating the extracellular Ca²⁺ entry. This study aims to investigate the correlation of TRPV4, TRPV1, and TRPA1 with vascular change after the inferior gluteal artery perforator flap elevation. A total of 50 adult male SD rats were used in this study. Ten rats were used in the part one to assess the flap viability on postoperative day 7. Twenty rats were used in the part two to evaluate blood flow change after flap elevation. The correlation of vascular change with TRPV1, TRPV4, and TRPA1 protein changes was investigated in 20 rats in the part three. The mean flap survival area percentage was 55 ± 5.7%. Blood flow in the overall flap and Zone II after the flap elevation markedly increased from the postoperative day 3. The most marked change of the vasodilation occurred on Days 3 and 5 after flap elevation. The angiogenesis occurred on Day 5 after flap elevation and the microvessel density peaked also on Day 5. Moreover, TRPA1 expression showed a trend towards continuous reduction over time. The expression of TRPV1 and TRPV4 reached the peak value on Day 3. The endothelial NO synthase expression showed an increasing trend at first, followed by a reduction over time, while VEGF expression reached the peak value on Day 3. The vascular changes after flap elevation might be associated with the changes in TRPV4, TRPV1, and TRPA1.

Cross-Talk between Mechanosensitive Ion Channels and Calcium Regulatory Proteins in Cardiovascular Health and Disease

Mechanosensitive ion channels are widely expressed in the cardiovascular system. They translate mechanical forces including shear stress and stretch into biological signals. The most prominent biological signal through which the cardiovascular physiological activity is initiated or maintained are intracellular calcium ions (Ca²⁺). Growing evidence show that the Ca²⁺ entry mediated by mechanosensitive ion channels is also precisely regulated by a variety of key proteins which are distributed in the cell membrane or endoplasmic reticulum. Recent studies have revealed that mechanosensitive ion channels can even physically interact with Ca²⁺ regulatory proteins and these interactions have wide implications for physiology and pathophysiology. Therefore, this paper reviews the cross-talk between mechanosensitive ion channels and some key Ca²⁺ regulatory proteins in the maintenance of calcium homeostasis and its relevance to cardiovascular health and disease.