Stimulation of TRPA1 attenuates ischemia-induced cardiomyocyte cell death through an eNOS-mediated mechanism

Airway and cardiovascular remodeling in chronic obstructive pulmonary disease (COPD) as a target for transient receptor potential ankyrin 1 (TRPA1) channel modulators

Chronic obstructive pulmonary disease (COPD) is characterized by chronic inflammation, which leads to airway remodeling (AR). AR refers to various structural changes occurring in the airway wall, resulting in thickening, and narrowing of the airways. Apart from airways, and lung tissue, pulmonary vasculature also undergoes remodeling. Thus, the pressure in vascular bed is increased, leading to pulmonary hypertension and further right and left ventricle hypertrophy, as well as myocardial fibrosis. Currently, there is lack of effective treatment directly targeting airway and cardiovascular remodeling in the course of COPD. Due to a lot of research showing involvement of transient receptor potential ankyrin 1 (TRPA1) in respiratory disorders, it seems reasonable to consider this ion channel as a molecular target in treatment of remodeling consequences of COPD. The aim of this review is to summarize current knowledge of its role in this case and to identify areas requiring further research. Moreover, we provide few patented structures intended to treat chronic respiratory diseases, which may be worth investigating in the context of airway remodeling.

Protective Effect of Transient Receptor Potential Ankyrin 1 Inhibition on Renal Ischemia Reperfusion Injury in Rats

The transient receptor potential ankyrin 1 (TRPA1) channels, characterized as nonselective cation channels with permeability to calcium ions (Ca2 +), are part of the extensive family of transient receptor potential (TRP) channels. Research has demonstrated that TRPA1 channels function as sensors for oxidative stress in the renal tubules. Additionally, TRPA1 expression has increased in renal tissue following ischemia-reperfusion (IR). There is also a significant correlation between IR-induced renal injury and TRPA1 expression. This study investigated the effects of selective TRPA1 agonist ASP7663 and selective TRPA1 antagonist HC-030031 on renal IR injury. A total of 40 rats were divided into four groups: control, IR, IR+ASP7663, and IR + HC-030031. The rat kidneys were exposed to 45 min of ischemia, followed by 24 h of reperfusion. TRPA1 agonist ASP7663 and selective TRPA1 antagonist HC-030031 were administered intraperitoneally to the treatment groups with renal IR. HC-030031 administration reduced the elevated kidney injury molecule-1 (KIM-1), blood urea nitrogen (BUN), and creatinine (Cre) caused by renal IR. HC-030031 administration reduced the increased histopathological damage in renal tissue due to IR. It also reduced renal tissue interleukin-1beta (IL-1β), interleukin-6 (IL-6), toll-like receptor-4 (TLR-4), phosphorylated-NF-κB, phosphorylated-IκB-α, tumor necrosis factor-alpha (TNF-α), and caspase-3 levels. In this study, TRPA1 antagonist HC-030031 showed a protective behavior on renal IR injury by averting inflammation and apoptosis. After further studies, TRPA1 inhibition may be a new treatment strategy to prevent renal IR injury.

Open-Label Interventional Study in Healthy Volunteers to Evaluate NO-Mediated Vasodilation by Dermal Allyl Isothiocyanate Challenge and Whole-Body Heat Stress

Dermal allyl isothiocyanate (AITC) administration and whole-body heat stress (WBHS) are two challenge models that are used to evaluate physiological mechanisms of vasodilation and pharmacological activity in humans. Their exact vasodilatory mechanisms in humans are not fully elucidated but are likely to be nitric oxide (NO)-mediated. This study aimed to evaluate whether there is overlap in the vasodilatory pathways of dermal AITC application and WBHS by combining the challenges. In this open-label interventional study, healthy volunteers underwent dermal administration of AITC twice: under basal conditions and during WBHS. Dermal blood flow (DBF) was non-invasively measured using laser speckle contrast imaging four times, once in each of the following situations: baseline, WBHS only, AITC only, and WBHS combined with AITC. A total of 12 male volunteers, aged 18-61 years, participated in the study. Compared to baseline, following AITC application, their DBF increased by 63.43 AU (baseline: 32.55, 95% CI [17.78, 47.31] AU, AITC only: 95.97, 95% CI [81.21, 110.7] AU, p < 0.0001). During WBHS, the increase in DBF after AITC was 42.76 AU (WBHS only: 87.25, 95% CI [72.49, 102.0] AU, WBHS+AITC: 130.0, 95% CI [115.2, 144.8] AU, p < 0.0001). The combination of WBHS and AITC resulted in a lower DBF than the sum of the DBF responses to AITC and WBHS when applied separately (ED 20.67, 95% CI [-3.532, 44.88], p = 0.0916). This might point towards the presence of an interaction in the vasodilatory mechanism of AITC application and WBHS, possibly indicating overlap in their NOS-driven vasodilatory pathways.

Unveiling the role of TRPA1 in cardiovascular health and disease: a mini review

The transient receptor potential ankyrin 1 (TRPA1) ion channel has emerged as significant regulators of cardiovascular physiology and pathology. TRPA1 is a non-selective cation channel permeable to calcium ions. A unique feature of the channel is its function as a sensor of various temperature, chemical and mechanical stimuli, while it can also be activated by endogenous inflammatory mediators and reactive oxygen species. Over the last two decades, much progress has been made in illuminating the role of TRPA1 in the regulation of cardiovascular physiology and pathophysiology in addition to its important function in pain sensation. This review provides a comprehensive analysis of recent studies investigating the involvement of TRPA1 channels in various cardiovascular diseases, including myocardial infarction, ischemia-reperfusion injury, myocardial fibrosis, and response to environmental toxins. We discuss the diverse roles of TRPA1 channels in cardiac pathology and highlight their potential as therapeutic targets for cardiovascular disorders. Moreover, we explore the challenges and opportunities linked with targeting TRPA1 channels for treating cardiovascular diseases, alongside future research directions.

Regulation of bone homeostasis by traditional Chinese medicine active scaffolds and enhancement for the osteoporosis bone regeneration

ETHNOPHARMACOLOGICAL RELEVANCE

The active ingredients of traditional Chinese medicine (TCM), such as naringin (NG), Eucommiol, isopsoralen, icariin, Astragalus polysaccharides, and chondroitin sulfate, contained in Drynariae Rhizoma, Eucommiae Cortex, Psoralea corylifolia, Herba Epimedii, Astragalus radix and deer antler, are considered promising candidates for enhancing the healing of osteoporotic defects due to their outstanding bone homeostasis regulating properties. They are commonly used to activate bone repair scaffolds.

AIM OF THE REVIEW

Bone repair scaffolds are inadequate to meet the demands of osteoporotic defect healing due to the lack of regulation of bone homeostasis. Therefore, selecting bone scaffolds activated with TCM to improve the therapeutic effect of repairing osteoporotic bone defects.

MATERIALS AND METHODS

To gather information on bone scaffold activated by traditional Chinese medicine, we conducted a thorough search of several scientific databases, including Google Scholar, Web of Science, Scifinder, Baidu Scholar, PubMed, and China National Knowledge Infrastructure (CNKI).

RESULTS

This review discusses the mechanism of TCM active ingredients in regulating bone homeostasis, including stimulating bone formation and inhibiting bone resorption process and the healing mechanism of traditional bone repair scaffolds activated by them for osteoporotic defect healing.

CONCLUSION

In general, the introduction of TCM active ingredients provides a novel therapeutic approach for modulating bone homeostasis and facilitating osteoporotic defect healing, and also offers a new strategy for design of other unconventional bone defect healing materials.

A Mechanism for the Treatment of Cardiovascular and Renal Disease: TRPV1 and TRPA1

ABSTRACT

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality globally. CVD and kidney disease are closely related, with kidney injury increasing CVD mortality. The pathogenesis of cardiovascular and renal diseases involves complex and diverse interactions between multiple extracellular and intracellular signaling molecules, among which transient receptor potential vanilloid 1 (TRPV1)/transient receptor potential ankyrin 1 (TRPA1) channels have received increasing attention. TRPV1 belongs to the vanilloid receptor subtype family of transient receptor potential ion channels, and TRPA1 belongs to the transient receptor potential channel superfamily. TRPV1/TRPA1 are jointly involved in the management of cardiovascular and renal diseases and play important roles in regulating vascular tension, promoting angiogenesis, antifibrosis, anti-inflammation, and antioxidation. The mechanism of TRPV1/TRPA1 is mainly related to regulation of intracellular calcium influx and release of nitric oxide and calcitonin gene-related peptide. Therefore, this study takes the TRPV1/TRPA1 channel as the research object, analyzes and summarizes the process and mechanism of TRPV1/TRPA1 affecting cardiovascular and renal diseases, and lays a foundation for the treatment of cardiorenal diseases.

TRPA1 as a promising target in ischemia/reperfusion: A comprehensive review

Ischemic disorders, including myocardial infarction, cerebral ischemia, and peripheral vascular impairment, are the main common reasons for debilitating diseases and death in Western cultures. Ischemia occurs when blood circulation is reduced in tissues. Reperfusion, although commanded to return oxygen to ischemic tissues, generates paradoxical tissue responses. The responses include generating reactive oxygen species (ROS), stimulating inflammatory responses in ischemic organs, endoplasmic reticulum stress, and the expansion of postischemic capillary no-reflow, which intensifies organ damage. Multiple pathologic processes contribute to ischemia/reperfusion; therefore, targeting different pathologic processes may yield an effective therapeutic approach. Transient Receptor Potential A1 (TRPA1) belongs to the TRP family of ion channels, detects a broad range of chemicals, and promotes the transduction of noxious stimuli, e.g., methylglyoxal, ROS, and acrolein effects are attributed to the channel's sensitivity to intracellular calcium elevation or phosphoinositol phosphate modulation. Hypoxia and ischemia are associated with oxidative stress, which activates the TRPA1 channel. This review describes the role of TRPA1 and its related mechanisms that contribute to ischemia/reperfusion. Relevant articles were searched from PubMed, Scopus, Web of Sciences, and Google Scholar electronic databases, up to the end of August 2023. Based on the evidence presented here, TRPA1 may have protective or deteriorative functions during the ischemia/reperfusion process. Its function depends on the activation level, the ischemic region, the extent of lesions, and the duration of ischemia.

Allyl Isothiocianate Induces Ca2+ Signals and Nitric Oxide Release by Inducing Reactive Oxygen Species Production in the Human Cerebrovascular Endothelial Cell Line hCMEC/D3

Nitric oxide (NO) represents a crucial mediator to regulate cerebral blood flow (CBF) in the human brain both under basal conditions and in response to somatosensory stimulation. An increase in intracellular Ca2+ concentrations ([Ca2+]i) stimulates the endothelial NO synthase to produce NO in human cerebrovascular endothelial cells. Therefore, targeting the endothelial ion channel machinery could represent a promising strategy to rescue endothelial NO signalling in traumatic brain injury and neurodegenerative disorders. Allyl isothiocyanate (AITC), a major active constituent of cruciferous vegetables, was found to increase CBF in non-human preclinical models, but it is still unknown whether it stimulates NO release in human brain capillary endothelial cells. In the present investigation, we showed that AITC evoked a Ca2+-dependent NO release in the human cerebrovascular endothelial cell line, hCMEC/D3. The Ca2+ response to AITC was shaped by both intra- and extracellular Ca2+ sources, although it was insensitive to the pharmacological blockade of transient receptor potential ankyrin 1, which is regarded to be among the main molecular targets of AITC. In accord, AITC failed to induce transmembrane currents or to elicit membrane hyperpolarization, although NS309, a selective opener of the small- and intermediate-conductance Ca2+-activated K+ channels, induced a significant membrane hyperpolarization. The AITC-evoked Ca2+ signal was triggered by the production of cytosolic, but not mitochondrial, reactive oxygen species (ROS), and was supported by store-operated Ca2+ entry (SOCE). Conversely, the Ca2+ response to AITC did not require Ca2+ mobilization from the endoplasmic reticulum, lysosomes or mitochondria. However, pharmacological manipulation revealed that AITC-dependent ROS generation inhibited plasma membrane Ca2+-ATPase (PMCA) activity, thereby attenuating Ca2+ removal across the plasma membrane and resulting in a sustained increase in [Ca2+]i. In accord, the AITC-evoked NO release was driven by ROS generation and required ROS-dependent inhibition of PMCA activity. These data suggest that AITC could be exploited to restore NO signalling and restore CBF in brain disorders that feature neurovascular dysfunction.

TRPA1 as Target in Myocardial Infarction

Transient receptor potential cation channel subfamily A member 1 (TRPA1), an ion channel primarily expressed on sensory neurons, can be activated by substances occurring during myocardial infarction. Aims were to investigate whether activation, inhibition, or absence of TRPA1 affects infarcts and to explore underlying mechanisms. In the context of myocardial infarction, rats received a TRPA1 agonist, an antagonist, or vehicle at different time points, and infarct size was assessed. Wild type and TRPA1 knockout mice were also compared in this regard. In vitro, sensory neurons were co-cultured with cardiomyocytes and subjected to a model of ischemia-reperfusion. Although there was a difference between TRPA1 activation or inhibition in vivo, no experimental group was different to control animals in infarct size, which also applies to animals lacking TRPA1. In vitro, survival probability of cardiomyocytes challenged by ischemia-reperfusion increased from 32.8% in absence to 45.1% in presence of sensory neurons, which depends, at least partly, on TRPA1. This study raises doubts about whether TRPA1 is a promising target to reduce myocardial damage within a 24 h period. The results are incompatible with relevant enlargements of infarcts by TRPA1 activation or inhibition, which argues against adverse effects when TRPA1 is targeted for other indications.

Are TRPA1 and TRPV1 channel-mediated signalling cascades involved in UVB radiation-induced sunburn?

Burn injuries are underappreciated injuries associated with substantial morbidity and mortality. Overexposure to ultraviolet (UV) radiation has dramatic clinical effects in humans and is a significant public health concern. Although the mechanisms underlying UVB exposure are not fully understood, many studies have made substantial progress in the pathophysiology of sunburn in terms of its molecular aspects in the last few years. It is well established that the transient receptor potential ankyrin 1 (TRPA1), and vanilloid 1 (TRPV1) channels modulate the inflammatory, oxidative, and proliferative processes underlying UVB radiation exposure. However, it is still unknown which mechanisms underlying TRPV1/A1 channel activation are elicited in sunburn induced by UVB radiation. Therefore, in this review, we give an overview of the TRPV1/A1 channel-mediated signalling cascades that may be involved in the pathophysiology of sunburn induced by UVB radiation. These data will undoubtedly help to explain the various features of sunburn and contribute to the development of novel therapeutic approaches to better treat it.

Pharmacological modulation of prostaglandin E2 (PGE2 ) EP receptors improves cardiomyocyte function under hyperglycemic conditions

Type 2 diabetes (T2D) affects >30 million Americans and nearly 70% of individuals with T2D will die from cardiovascular disease (CVD). Circulating levels of the inflammatory signaling lipid, prostaglandin E2 (PGE2 ), are elevated in the setting of obesity and T2D and are associated with decreased cardiac function. The EP3 and EP4 PGE2 receptors have opposing actions in several tissues, including the heart: overexpression of EP3 in cardiomyocytes impairs function, while EP4 overexpression improves function. Here we performed complementary studies in vitro with isolated cardiomyocytes and in vivo using db/db mice, a model of T2D, to analyze the effects of EP3 inhibition or EP4 activation on cardiac function. Using echocardiography, we found that 2 weeks of systemic treatment of db/db mice with 20 mg/kg of EP3 antagonist, beginning at 6 weeks of age, improves ejection fraction and fractional shortening (with no effect on heart rate). We further show that either EP3 blockade or EP4 activation enhances contractility and calcium cycling in isolated mouse cardiomyocytes cultured in both normal and high glucose. Thus, peak [Ca2+ ]I transient amplitude was increased, while time to peak [Ca2+ ]I and [Ca2+ ]I decay were decreased. These data suggest that modulation of EP3 and EP4 activity has beneficial effects on cardiomyocyte contractility and overall heart function.

Energy-sparing by 2-methyl-2-thiazoline protects heart from ischaemia/reperfusion injury

AIMS

Cardiac ischaemia/reperfusion (I/R) injury remains a critical issue in the therapeutic management of ischaemic heart failure. Although mild hypothermia has a protective effect on cardiac I/R injury, more rapid and safe methods that can obtain similar results to hypothermia therapy are required. 2-Methyl-2-thiazoline (2MT), an innate fear inducer, causes mild hypothermia resulting in resistance to critical hypoxia in cutaneous or cerebral I/R injury. The aim of this study is to demonstrate the protective effect of systemically administered 2MT on cardiac I/R injury and to elucidate the mechanism underlying this effect.

METHODS AND RESULTS

A single subcutaneous injection of 2MT (50 mg/kg) was given prior to reperfusion of the I/R injured 10 week-old male mouse heart and its efficacy was evaluated 24 h after the ligation of the left anterior descending coronary artery. 2MT preserved left ventricular systolic function following I/R injury (ejection fraction, %: control 37.9 ± 6.7, 2MT 54.1 ± 6.4, P < 0.01). 2MT also decreased infarct size (infarct size/ischaemic area at risk, %: control 48.3 ± 12.1, 2MT 25.6 ± 4.2, P < 0.05) and serum cardiac troponin levels (ng/mL: control 8.9 ± 1.1, 2MT 1.9 ± 0.1, P < 0.01) after I/R. Moreover, 2MT reduced the oxidative stress-exposed area within the heart (%: control 25.3 ± 4.7, 2MT 10.8 ± 1.4, P < 0.01). These results were supported by microarray analysis of the mouse hearts. 2MT induced a transient, mild decrease in core body temperature (°C: -2.4 ± 1.4), which gradually recovered over several hours. Metabolome analysis of the mouse hearts suggested that 2MT minimized energy metabolism towards suppressing oxidative stress. Furthermore, 18F-fluorodeoxyglucose-positron emission tomography/computed tomography imaging revealed that 2MT reduced the activity of brown adipose tissue (standardized uptake value: control 24.3 ± 6.4, 2MT 18.4 ± 5.8, P < 0.05). 2MT also inhibited mitochondrial respiration and glycolysis in rat cardiomyoblasts.

CONCLUSIONS

We identified the cardioprotective effect of systemically administered 2MT on cardiac I/R injury by sparing energy metabolism with reversible hypothermia. Our results highlight the potential of drug-induced hypothermia therapy as an adjunct to coronary intervention in severe ischaemic heart disease.

The role of transient receptor potential ankyrin 1 in age-related endothelial dysfunction

Oxidative stress plays a key role in age-related vascular disease. The present study aimed to investigate the role of an antioxidant channel, transient receptor potential ankyrin 1 (TRPA1), in age-related endothelial dysfunction. Human umbilical vein endothelial cells (HUVECs) were grown to induce replicative senescence, and 6-month-old young, 12-month-old middle-aged, and 24-month-old aged mice were used. TRPA1 was downregulated in senescent HUVECs, so were endothelial nitric oxide synthase (eNOS), nuclear factor erythroid 2-related factor 2 (Nrf2), and uncoupling protein 2 (UCP2). Activating TRPA1 with cinnamaldehyde prevented downregulation of eNOS, Nrf2, and UCP2, inhibited superoxide production and apoptosis, and preserved nitric oxide bioavailability in senescent HUVECs. TRPA1, phosphorylated eNOS, Nrf2 and UCP2 were significantly downregulated in aged aortas compared with young aortas after a compensatory upregulation in middle-aged aortas. Dietary administration of cinnamaldehyde for 12 months prevented mitochondrial dysfunction, improved endothelium-dependent relaxation, and increased expression of eNOS, Nrf2, and UCP2 in aged aortas. Importantly, the effects of cinnamaldehyde can be blocked by a TRPA1 antagonist HC-030031. These findings suggest that TRPA1 may play a critical role in age-related endothelial dysfunction and may become a therapeutic target for the treatment and prevention of age-related vascular disease.

No functional TRPA1 in cardiomyocytes

AIM

There is mounting evidence that TRPA1 has a role in cardiac physiology and pathophysiology. We aim to clarify the site of TRPA1 expression in the heart and in particular whether the channel is expressed in cardiomyocytes.

METHODS

Due to the high calcium conductance of TRPA1, and marginal calcium changes being detectable, microfluorimetry in primary mouse cardiomyocytes, and in the cardiomyocyte cell lines H9c2 and HL-1, was applied. TRPA1 mRNA in mouse and human hearts, primary cardiomyocytes, and the cardiac cell lines were quantified. Dorsal root ganglia served as control for both methods.

RESULTS

In addition to AITC, the more potent and specific TRPA1 agonists JT010 and PF-4840154 failed to elicit a TRPA1-mediated response in native and electrically paced primary cardiomyocytes, and the cardiomyocyte cell lines H9c2 and HL-1. There were only marginal levels of TRPA1 mRNA in cardiomyocytes and cardiac cell lines, also in conditions of cell differentiation or inflammation, which might occur in pathophysiological conditions. Similarly, TRPV1 agonist capsaicin did not activate primary mouse cardiomyocytes, did not alter electrically paced activity in these, and did not activate H9c2 cells or alter spontaneous activity of HL-1 cells. Human pluripotent stem cells differentiated to cardiomyocytes had no relevant TRPA1 mRNA levels. Also in human post-mortem heart samples, TRPA1 mRNA levels were substantially lower compared with the respective dorsal root ganglion.

CONCLUSION

The results do not question a role of TRPA1 in the heart but exclude a direct effect in cardiomyocytes.

IcyHot analgesic topical cream limits cardiac injury in rodents

Little is known whether topical analgesic creams, whose natural products enter the blood stream after application, affect myocardial infarct size. Here we tested whether topical analgesic creams can trigger remote cardioprotection and the mechanism involved. Male Sprague Dawley rats were used for an in vivo rodent model consisting of 30 minutes left anterior descending coronary artery ischemia and 2 hours of reperfusion followed by infarct size assessment. The topical analgesic IcyHot, applied to the abdomen prior to ischemia, reduced myocardial infarct size versus control (41 ± 3* vs 62 ± 1, n= 6/group, *P < 0.001). In contrast, the topical analgesic creams Preparation H, Aspercreme Heat, or Tiger Balm did not alter infarct size. IcyHot, unlike Preparation H, increased circulating methyl salicylate levels during reperfusion (3.0 ± 0.6 vs 0.4 ± 0.2 mg/dL, n = 6, *P < 0.001, measured at the internal jugular vein). Methyl salicylate (10 μM) applied to isolated adult cardiac myocytes during reoxygenation reduced cell death when compared to vehicle (21% ± 2%* vs 30% ± 2% of trypan blue positive cells, n = 9/group, *P < 0.01). Further, treatment with the TRP ankyrin 1 (TRPA1) inhibitors TCS-5861528 (1 μM) or AP-18 (1 μM) blocked the methyl salicylate-induced protective effect in isolated adult cardiomyocytes. In intact rodents, either of the TRPA1 inhibitors (1 mg/kg, intravenous) given prior to IcyHot topical application blocked IcyHot-induced infarct size reduction. IcyHot also reduced infarct size when applied 24 hours prior to myocardial ischemia or during myocardial ischemia versus control. Together, these findings support IcyHot analgesic cream can trigger remote cardioprotection through releasing methyl salicylate into the bloodstream with cardioprotection occurring by a TRPA1-dependent mechanism.