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Xinyu Wu,* Daoyan Liu,* Shuzhen Wang, Jie Liu Department of Laboratory Medicine, The Affiliated Maternity and Child Health Care Hospital, Xuzhou Medical University, Xuzhou 221009, People’s Republic of China*These authors contributed equally to this workCorrespondence: Jie LiuDepartment of Laboratory Medicine, The Affiliated Maternity and Child Health Care Hospital, Xuzhou Medical University, NO. 46 Heping Road, Xuzhou 221009, People’s Republic of ChinaTel +86-516-83907033Email liujie_xuzhoumu@163.comShuzhen WangEmail Email wangshuzhen116@163.comPurpose: Some circular RNAs have been found to be effective therapeutic targets for OC. However, the biological function of circ_0007444 in OC is still unknown. Thus, this study investigated the role of circ_0007444 in OC progression.Methods: circ_0007444 expression was monitored in 87 OC patients and OC cells by quantitative real-time polymerase chain reaction. An in vitro study was performed to research the biological function of circ_0007444, including cell counting kit-8 assay, flow cytometry, wound healing assay, and transwell experiment. Luciferase reporter gene assay and RNA immunoprecipitation assay were used to reveal the interaction between circ_0007444, miR-570-3p, and PTEN. PTEN protein expression was determined by Western blot. In vivo study was performed using nude mice. Ki67, PTEN expression, and apoptosis in xenograft tumors was respectively researched by immunohistochemistry and Tunel assay.Results: circ_0007444 was down-regulated in 87 OC patients, which was related to advanced tumor stage and grade, large tumor size, and low 60-month percent survival (P< 0.05 or P< 0.01). circ_0007444 inhibited proliferation, migration, and invasion, and promoted apoptosis of OC cells (P< 0.01). circ_0007444 promoted PTEN expression via sponging miR-570-3p. miR-570-3p up-regulation and PTEN down-regulation reversed the inhibitory effect of circ_0007444 on OC cells malignant phenotype (P< 0.01). circ_0007444 inhibited OC growth in vivo. In xenograft tumor, circ_0007444 decreased Ki67 expression but increased PTEN expression and apoptosis.Conclusion: circ_0007444 is a tumor suppressor in OC, which inhibits OC progression by mediating the miR-570-3p/PTEN. circ_0007444 can be a potential candidate for targeted therapy of OC.Keywords: OC, circ_0007444, miR-570-3p, PTEN, progression

High salt intake is a known risk factor of cardiovascular diseases. Our recent study demonstrated that long-term high salt intake impairs transient receptor potential channel M5 (TRPM5)-mediated aversion to high salt concentrations, consequently promoting high salt intake and hypertension; however, it remains unknown whether TRPM5 activation ameliorates cardiovascular dysfunction. Herein we found that bitter melon extract (BME) and cucurbitacin E (CuE), a major compound in BME, lowered high salt-induced hypertension. Long-term BME intake significantly enhanced the aversion to high salt concentrations by upregulating TRPM5 expression and function, eventually decreasing excessive salt consumption in mice. Moreover, dietary BME ameliorated high salt-induced cardiovascular dysfunction and angiotensin II-induced hypertension in vivo. The mechanistic evidence demonstrated that dietary BME inhibited high salt-induced RhoA/Rho kinase pathway overactivation, leading to reduced phosphorylation levels of myosin light chain kinase and myosin phosphatase targeting subunit 1. Furthermore, CuE inhibited vasoconstriction by attenuating L-type Ca2+ channel-induced Ca2+ influx in vascular smooth muscle cells. To summarize, our findings indicate that dietary BME has a beneficial role in antagonizing excessive salt consumption and thus appears promising for the prevention of high salt-induced cardiovascular dysfunction.

Excessive salt consumption leads to cardiovascular diseases. Despite various measures designed to reduce salt intake, daily salt intake remains at a high level. Appropriate salt intake is balanced by salt taste preference triggered by epithelium sodium channel and salt taste aversion evoked by bitter taste sensor, transient receptor potential channel M5 (TRPM5). However, the behavioral mechanism of excessive salt intake remains largely elusive. In this study, wild type and TRPM5 −/− mice were applied to study the influence of high-salt administration on epithelium sodium channel/TRPM5 and the associated behavior to salt consumption. We found that long-term high-salt intake impaired the aversive behavior to high-salt stimulation but did not alter the preference to low salt in mice. The mechanistic evidence demonstrated that high-salt intake blunted the TRPM5-mediated aversive behavior to noxious salt stimulation through inhibiting PKC (protein kinase C) activity and PKC-dependent threonine phosphorylation in the tongue epithelium but did not affect the epithelium sodium channel–dependent salt taste preference. Inhibition of TRPM5 also resulted in an impaired aversive response to high salt, with reduced taste perception in bitter cortical field of mice. TRPM5 −/− mice showed a lowered aversion to high-salt diet and developed salt-induced hypertension. The impaired perception to bitter taste evoked by high-salt intake also existed in hypertensive patients with high-salt consumption. We demonstrate that long-term high-salt consumption impairs aversive response to concentrated salt by downregulating bitter taste sensor TRPM5. It suggests that enhancing TRPM5 function might antagonize excessive salt intake and high salt–induced hypertension.

Objective. Myofibroblast transformation has been shown to be associated with the reactive oxygen species- (ROS-) producing enzyme NADPH oxidase (Nox4). Inhibition of transient receptor potential channel canonical type 3 (TRPC3) attenuates mitochondrial calcium handling and ROS production in the vasculature of hypertensive rats. However, it remains elusive whether TRPC3 regulates mitochondrial calcium and ROS production and participates in myofibroblast transdifferentiation during wound healing. Methods and Results. In this study, we demonstrated that activation of TRPC3 by transforming growth factor β (TGFβ1) elevated myofibroblast transdifferentiation by upregulating the myofibroblast marker alpha smooth muscle actin (αSMA). Inhibition of TRPC3 with its specific inhibitor, Pyr3, significantly decreased TGFβ1-induced αSMA expression, as demonstrated by immunofluorescence. Real-time PCR and immunohistochemistry revealed higher TRPC3 and TGFβ1 mRNA expression levels in fibroblasts from hypertrophic scar (HTS) tissue than in those from normal skin tissue. TGFβ1 treatment increased TRPC3-mediated mitochondrial calcium uptake and ROS production but decreased ATP content in human fibroblasts, whereas inhibition of TRPC3 significantly reversed these effects. The beneficial effects were associated with improvements in mitochondrial respiratory function mediated by recovery of the activity of pyruvate dehydrogenase (PDH). In vivo, Trpc3-/- mice exhibited significantly attenuated myofibroblast transdifferentiation, as demonstrated by decreased αSMA, TGFβ1, fibronectin, and collagen-1 (Col1a1) protein expression in wound granulation tissues. Furthermore, TGFβ1-induced store-operated calcium entry (SOCE) was significantly decreased in fibroblasts from Trpc3-/- mice compared with those from Trpc3+/+ mice. In addition, Trpc3-/- mice exhibited significantly decreased Nox4 and phosphorylated Smad2/3 protein expression in wound granulation tissues. Conclusions. Our data indicate that TGFβ1-mediated activation of TRPC3 enhances mitochondrial calcium and ROS production, which promotes myofibroblast transdifferentiation and HTS formation. Inhibition of the TRPC3-mediated Nox4/pSmad2/3 pathway may be a useful strategy to limit HTS formation after injury.

Summary: High salt intake is one independent risk factor for cardiac hypertrophy. Polycystic kidney disease 2-like 1 (PKD2L1, also called TRPP3) acts as a sour sensor in taste cells, and its possible role in the cardiovascular system is unknown. Here, we report that knockout of PKD2L1 exacerbated high-salt diet (HSD)-induced cardiac hypertrophy and fibrosis, accompanied by cardiac dysfunction and reduced cardiac mitochondrial oxidative phosphorylation and enzyme activity. Furthermore, knockdown of PKD2L1 led to more serious mitochondrial Ca2+ overload and reduced Ca2+ uptake in cardiomyocytes on high salt loading. Mechanistically, PKD2L1 deficiency increased p300-mediated acetylation of histone 3 lysine 27 on the promoter of sodium/calcium exchange 1 (NCX1) by repressing AMP-activated protein kinase (AMPK) activity, resulting in NCX1 overexpression and mitochondrial Ca2+ overload. These results reveal an inhibitory effect of PKD2L1 on cardiac hypertrophy and provide a mechanistic insight into the link between mitochondrial Ca2+ homeostasis and cardiac hypertrophy. : Lu et al. reveal a role of a mitochondria-localized TRPP member, PKD2L1, in high salt-induced cardiac hypertrophy. PKD2L1 knockout leads to overexpression of NCX1 through increasing the acetylation level of histone 3 lysine 27 on NCX1 promoter and thus exacerbates mitochondrial calcium overload by activating the reverse mode of NCX1 in cardiomyocytes. Keywords: high-salt diet, cardiac hypertrophy, PKD2L1, mitochondria, NCX1

Background/Aims: High salt consumption is a major risk factor for hypertension, and sodium homeostasis is regulated by both intestinal sodium absorption and urinary sodium excretion. Chronic caffeine intake has been reported to attenuate salt-sensitive hypertension by promoting urinary sodium excretion; however, its exact role in intestinal sodium absorption remains unknown. Here, we investigated whether and how chronic caffeine consumption antagonizes salt-sensitive hypertension by inhibiting intestinal sodium absorption. Methods: Dahl salt-sensitive rats were fed 8% NaCl chow and 0.1% caffeine in their drinking water for 15 days. The blood pressure and fecal sodium content were measured. The effect of caffeine on the movement of Cl- in enterocyte cells was determined with the Ussing chamber assay. Results: Rats that were treated with caffeine displayed significantly lower mean blood pressure and higher fecal sodium content than the controls. Consistent with these findings, caffeine intake decreased fluid absorption by the intestine in the fluid perfusion experiment. Further, the results from the Ussing chamber assay indicated that caffeine promoted Cl- secretion through enterocyte apical cystic fibrosis transmembrane conductance regulator (CFTR), and thus inhibited sodium absorption. Moreover, depletion of cAMP or inhibition of CFTR completely abolished the effect of caffeine on Cl- secretion. Conclusion: The results indicate that chronic caffeine consumption reduces sodium absorption by promoting CFTR-mediated Cl- secretion in the intestine, which contributes to the anti-hypertensive effect of caffeine in salt-sensitive rats.

Endothelial dysfunction is an early step to the progression of cardiovascular diseases in diabetes. Apart from their anti-diabetic action, DPP-4 (dipeptidyl peptidase-4) inhibitors also reduce cardiovascular events in diabetic patients. However, the underlying mechanism of the beneficial effect of DPP-4 inhibitor on endothelial function is still obscure. In this study, we intervened type 1 or 2 diabetic model mice with vildagliptin for 4 weeks and measured the vascular reactivity. We found that vildagliptin improved endothelium-dependent vasodilation in diabetic mice independent of GLP-1 (glucagonlike peptide-1), but this effect was blocked by a SIRT1 (Sirtuin 1) inhibitor, Ex527. Mechanistically, vildagliptin-activated Transient Receptor Potential Channel Vanilloid 4 (TRPV4) to promote extracellular calcium uptake in endothelial cells, which activated AMPK (AMP-activated protein kinase)/SIRT1 pathway to counteract hyperglycemia-induced endothelial reactive oxygen species generation and senescence. Vildagliptin directly binds to TRPV4 by forming a hydrogen bond, which is critical to vildagliptin-evoked endothelial calcium intake. Knockout or inhibition of TRPV4 erased the beneficial role of vildagliptin. In addition, activation of SIRT1 by SRT1720 improved endothelial function independent of TRPV4 and reduced TRPV4 transcription to maintain an appropriate calcium level. In summary, our findings prove that vildagliptin protects against hyperglycemia-induced endothelial dysfunction by activating TRPV4-meditaed Ca 2+ uptake, which helps to re-understand the mechanism of DPP-4 inhibitors and expand the therapeutic scope.

The whitening and loss of brown adipose tissue (BAT) during obesity and aging promote metabolic disorders and related diseases. The imbalance of Ca2+ homeostasis accounts for the dysfunction and clearance of mitochondria during BAT whitening. Capsaicin, a dietary factor activating TRPV1, can inhibit obesity induced by high-fat diet (HFD), but whether capsaicin inhibits BAT loss and the underlying mechanism remain unclear. In this study, we determined that the inhibitory effects of capsaicin on HFD-induced obesity and BAT whitening were dependent on the participation of SIRT3, a critical mitochondrial deacetylase. SIRT3 also mediated all of the beneficial effects of capsaicin on alleviating reactive oxygen species generation, elevating mitochondrial activity, and restricting mitochondrial calcium overload induced by HFD. Mechanistically, SIRT3 inhibits mitochondrial calcium uniporter (MCU)-mediated mitochondrial calcium overload by reducing the H3K27ac level on the MCU promoter in an AMPK-dependent manner. In addition, HFD also inhibits AMPK activity to reduce SIRT3 expression, which could be reversed by capsaicin. Capsaicin intervention also inhibited aging-induced BAT whitening through this mechanism. In conclusion, this study emphasizes a critical role of the AMPK/SIRT3 pathway in the maintenance of BAT morphology and function and suggests that intervention in this pathway may be an effective target for preventing obesity- or age-related metabolic diseases.

p53-dependent vascular smooth muscle cell senescence is a key pathological process of abdominal aortic aneurysm (AAA). Caloric restriction (CR) is a nonpharmacological intervention that prevents AAA formation. However, whether p53 is indispensable to the protective role of CR remains unknown. In this study, we investigated the necessity of p53 in the beneficial role of CR in AAA formation and the underlying mechanisms. We subjected p53 +/+ and p53 −/ − mice to 12 weeks of CR and then examined the incidence of Ang II (angiotensin II)–induced AAA formation. We found that both CR and p53 knockout reduced Ang II–induced AAA formation; however, CR markedly increased the incidence of AAA formation and exacerbated aortic elastin degradation in p53 −/− mice, accompanied by increased vascular senescence, reactive oxygen species generation, and reduced energy production. Analysis of mitochondrial respiratory activity revealed that dysfunctional complex IV accounts for the abnormal mitochondrial respiration in p53 −/− vascular smooth muscle cells treated by CR serum. Mechanistically, ablation of p53 almost totally blocked the protective role of CR by inhibiting SCO2 (cytochrome C oxidase assembly protein 2)-dependent mitochondrial complex IV activity. Overexpression of SCO2 restored the beneficial effect of CR on antagonizing Ang II–induced expression of AAA-related molecules and reactive oxygen species generation in p53 −/− vascular smooth muscle cells. Together, our findings demonstrate that the existence of p53 in vascular smooth muscle cells is critical to the protective role of CR in Ang II-induced AAA formation by maintaining an appropriate mitochondrial function.

High sodium intake is a major risk factor for developing hypertension in diabetes. Promotion of sodium excretion reduces cardiometabolic lesions in diabetes. However, the interaction between sodium intake and glucose homeostasis remains elusive. Here, we report that high sodium intake remarkably increased natriuresis in wild-type mice, but this effect was blunted in adipose-specific PPARδ knockout mice and diabetic mice. PPARδ activation in perirenal fat by agonist or high sodium intake inhibited renal sodium-glucose cotransporter 2 (SGLT2) function, which is mediated by increased production of adipose adiponectin. In addition, high salt intake-induced natriuresis was impaired in diabetic states because of renal SGLT2 dysfunction. Type 2 diabetic patients with uncontrolled hyperglycemia had less natriuresis that was correlated to their plasma adiponectin levels. Our findings provide insights into the distinctive role of the PPARδ/adiponectin/SGLT2 pathway in the regulation of sodium and glucose homeostasis.

Diabetic nephropathy (DN) is a major complication of diabetes mellitus and a primary cause of end-stage renal failure. Clinical studies indicate that metabolic surgery improves DN; however, the mechanism remains unclear. Here, we report that Roux-en-Y Gastric Bypass (RYGB) surgery significantly blocked and reversed DN without affecting the insulin signaling pathway. This protective role of RYGB surgery is almost blocked by either inhibition or knockout of 5′AMP-activated protein kinase (AMPK) in podocytes. Furthermore, mRNA microarray data reveal that RYGB surgery obviously reduced the gene expression involved in nicotinamide adenine dinucleotide phosphate (NAPDH) synthesis. The expression of a key NADPH synthase, hexose-6-phosphate dehydrogenase (H6PD), was inhibited by the low plasma corticosterone level after surgery. In addition, blocking NAPDH synthesis by knocking down H6PD mimicked the beneficial role of RYGB surgery through activation of AMPK in podocytes. Therefore, this study demonstrates that reducing NADPH production is critical for renal AMPK activation in response to RYGB surgery.

The impairment of podocyte protein filtration function caused by excessive mitochondrial calcium intake is a critical feature of diabetic nephropathy (DN). Ca2+ channel transient receptor potential cation channel subfamily V member 1 (TRPV1) has been reported to protect against ischemia-reperfusion induced acute renal injury, but there is no report about its role in DN. Here, we report that dietary capsaicin potently inhibits and reverses chronic renal structural and functional damages in db/db or streptozotocin (STZ)-induced diabetic mice in a TRPV1-dependent manner. Activation of TRPV1 by capsaicin alleviated hyperglycemia-induced mitochondrial dysfunction in podocytes, accompanied by reduced mitochondria-associated membranes (MAMs) formation and fewer Ca2+ transport from endoplasmic reticulum (ER) to mitochondria. Mechanistically, TRPV1-mediated transient Ca2+ influx activated 5' AMP-activated protein kinase (AMPK) that reduced the transcription of Fundc1, a key molecule participating in MAMs formation. Inhibition of AMPK or overexpression of Fundc1 obviously blocked the inhibitory effect of capsaicin on MAMs formation and functional decline in podocytes. These findings emphasize the critical role of mitochondrial Ca2+ homeostasis in the maintenance of normal renal function and suggest an effective intervention method to counteract DN.

Background and Purpose High-salt diet induces cardiac remodelling and leads to heart failure, which is closely related to cardiac mitochondrial dysfunction. Transient receptor potential (TRP) channels are implicated in the pathogenesis of cardiac dysfunction. We investigated whether activation of TRP vanilloid (subtype 1) (TRPV1) channels by dietary capsaicin can, by ameliorating cardiac mitochondrial dysfunction, prevent high-salt diet-induced cardiac hypertrophy. Experimental Approach Male wild-type (WT) and TRPV1−/− mice were fed a normal or high-salt diet with or without capsaicin for 6 months. Their cardiac parameters and endurance capacity were assessed. Mitochondrial respiration and oxygen consumption were measured using high-resolution respirometry. The expression levels of TRPV1, sirtuin 3 and NDUFA9 were detected in cardiac cells and tissues. Key Results Chronic high-salt diet caused cardiac hypertrophy and reduced physical activity in mice; both effects were ameliorated by capsaicin intake in WT but not in TRPV1−/− mice. TRPV1 knockout or high-salt diet significantly jeopardized the proficiency of mitochondrial Complex I oxidative phosphorylation (OXPHOS) and reduced Complex I enzyme activity. Chronic dietary capsaicin increased cardiac mitochondrial sirtuin 3 expression, the proficiency of Complex I OXPHOS, ATP production and Complex I enzyme activity in a TRPV1-dependent manner. Conclusions and Implications TRPV1 activation by dietary capsaicin can antagonize high-salt diet-mediated cardiac lesions by ameliorating its deleterious effect on the proficiency of Complex I OXPHOS. TRPV1-mediated amendment of mitochondrial dysfunction may represent a novel target for management of early cardiac dysfunction. Linked Articles This article is part of a themed section on Chinese Innovation in Cardiovascular Drug Discovery. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2015.172.issue-23

Background Environmental cold‐induced hypertension is common, but how to treat cold‐induced hypertension remains an obstacle. Transient receptor potential melastatin subtype 8 (TRPM8) is a mild cold‐sensing nonselective cation channel that is activated by menthol. Little is known about the effect of TRPM8 activation by menthol on mitochondrial Ca 2+ homeostasis and the vascular function in cold‐induced hypertension. Methods and Results Primary vascular smooth muscle cells from wild‐type or Trpm8 −/− mice were cultured. In vitro, we confirmed that sarcoplasmic reticulum–resident TRPM8 participated in the regulation of cellular and mitochondrial Ca 2+ homeostasis in the vascular smooth muscle cells. TRPM8 activation by menthol antagonized angiotensin II induced mitochondrial respiratory dysfunction and excess reactive oxygen species generation by preserving pyruvate dehydrogenase activity, which hindered reactive oxygen species–triggered Ca 2+ influx and the activation of RhoA/Rho kinase pathway. In vivo, long‐term noxious cold stimulation dramatically increased vasoconstriction and blood pressure. The activation of TRPM8 by dietary menthol inhibited vascular reactive oxygen species generation, vasoconstriction, and lowered blood pressure through attenuating excessive mitochondrial reactive oxygen species mediated the activation of RhoA/Rho kinase in a TRPM8‐dependent manner. These effects of menthol were further validated in angiotensin II–induced hypertensive mice. Conclusions Long‐term dietary menthol treatment targeting and preserving mitochondrial function may represent a nonpharmaceutical measure for environmental noxious cold–induced hypertension.

Background Mitochondrial Ca 2+ homeostasis is fundamental to the regulation of mitochondrial reactive oxygen species ( ROS ) generation and adenosine triphosphate production. Recently, transient receptor potential channel, canonical type 3 ( TRPC 3), has been shown to localize to the mitochondria and to play a role in maintaining mitochondrial calcium homeostasis. Inhibition of TRPC 3 attenuates vascular calcium influx in spontaneously hypertensive rats ( SHR s). However, it remains elusive whether mitochondrial TRPC 3 participates in hypertension by increasing mitochondrial calcium handling and ROS production. Methods and Results In this study we demonstrated increased TRPC 3 expression in purified mitochondria in the vasculature from SHR s, which facilitates enhanced mitochondrial calcium uptake and ROS generation compared with Wistar‐Kyoto rats. Furthermore, inhibition of TRPC 3 by its specific inhibitor, Pyr3, significantly decreased the vascular mitochondrial ROS production and H 2 O 2 synthesis and increased adenosine triphosphate content. Administration of telmisartan can improve these abnormalities. This beneficial effect was associated with improvement of the mitochondrial respiratory function through recovering the activity of pyruvate dehydrogenase in the vasculature of SHR s. In vivo, chronic administration of telmisartan suppressed TRPC 3‐mediated excessive mitochondrial ROS generation and vasoconstriction in the vasculature of SHR s. More importantly, TRPC 3 knockout mice exhibited significantly ameliorated hypertension through reduction of angiotensin II –induced mitochondrial ROS generation. Conclusions Together, we give experimental evidence for a potential mechanism by which enhanced TRPC 3 activity at the cytoplasmic and mitochondrial levels contributes to redox signaling and calcium dysregulation in the vasculature from SHR s. Angiotensin II or telmisartan can regulate [Ca 2+ ] mito , ROS production, and mitochondrial energy metabolism through targeting TRPC 3.

Background Metabolic syndrome has received great attention because it poses a potential cardiovascular hazard, which increases the risk of lower extremity atherosclerosis. However, the relationship between the components of metabolic syndrome and the onset of chronic venous disorder of the lower extremities remains unexplained. Methods This study investigated the characteristics of cardiometabolic risk factors of early chronic venous disorder of the lower extremities in subjects with cardiometabolic risk. The characteristics of risk factors and diabetes-related complications in diabetic patients with early chronic venous disorder of the lower extremities were also investigated. In addition, the association between early chronic venous disorder and atherosclerosis of the lower extremities was analysed. The study examined 782 subjects with cardiometabolic risk factors, including obesity, hypertension, diabetes mellitus and dyslipidaemia. Lower extremity venous function was measured by digital photoplethysmography. Results Women had a higher prevalence of early chronic venous disorder than did men (p

Environmental cold is a nonmodifiable hypertension risk factor. Transient receptor potential melastatin subtype 8 (TRPM8) is a cold-sensing cation channel that can be activated by menthol, a compound with a naturally cold sensation in mint. Little is known about the effect of TRPM8 activation on vascular function and blood pressure. Here, we report that TRPM8 is abundantly expressed in the vasculature. TRPM8 activation by menthol attenuated vasoconstriction via RhoA/Rho kinase pathway inhibition in wild-type mice, but the effect was absent in TRPM8 −/− mice. Chronic dietary menthol blunted mesenteric arterial constriction and lowered blood pressure in genetic hypertensive rats via inhibition of RhoA/Rho kinase expression and activity in the vivo study. TRPM8 effect was associated with inhibition of intracellular calcium release from the sarcoplasmic reticulum, RhoA/Rho kinase activity, and sustained arterial contraction in the vitro study. Importantly, 8-week chronic menthol capsule treatment moderately lowered systolic blood pressure and diastolic blood pressure in prehypertensive individuals compared with the placebo group. Furthermore, chronic menthol capsule administration also improved flow-mediated dilatation in prehypertensive individuals, but not in the placebo group. In conclusion, our study demonstrates that TRPM8 activation by menthol benefits vascular function and blood pressure by inhibiting calcium signaling–mediated RhoA/Rho kinase activation in the vasculature. These findings add to the evidence that long-term dietary menthol treatment had favorable effects on hypertension treatment.

Nonalcoholic fatty liver disease (NAFLD) is characterized by hepatic lipid deposition and coincides often with cardiometabolic diseases. Several dietary factors attenuate NAFLD. Here, we report beneficial effects of chronic dietary capsaicin intake on NAFLD which is mediated by the transient receptor potential vanilloid 1 (TRPV1) activation. The results showed that TRPV1 activation by capsaicin reduced free fatty acids (FFAs) induced the intracellular lipid droplets in HepG2 cells and prevented fatty liver in vivo. Chronic dietary capsaicin promoted lipolysis by increasing hepatic phosphorylated hormone-sensitive lipase (phospho-HSL), carnitine palmitoyltransferase 1 (CPT1), and peroxisome proliferator-activated receptor δ (PPARδ) in wild-type (WT) mice. This effect was absent in TRPV1(-/-) mice. Dietary capsaicin did not affect lipogenesis, as indicated by the detection of hepatic fatty acid synthase (FAS), sterol regulatory element-binding protein-1 (SREBP-1), PPARα, and liver X receptor (LXR) in mice. Importantly, TRPV1 causes PPARδ activation which significantly increased the expression of autophagy-related proteins, such as light chain 3 (LC3)II, Beclin1, Atg5, and Atg7 in HepG2 cells. In the in vivo study, TRPV1 activation by dietary capsaicin enhanced hepatic PPARδ and autophagy-related proteins and reduced hepatic enzymes and inflammatory factor in WT but not TRPV1(-/-) mice. TRPV1 activation by dietary capsaicin prevents NAFLD through PPARδ-dependent autophagy enhancement in mice. Dietary capsaicin may represent a beneficial intervention in populations at high risk for NAFLD.

Objective: Obesity is a prominent component of metabolic syndrome and a major risk factor for renal disease. The aim of this study was to explore the effect of cross-talk between peroxisome proliferator-activated receptor (PPAR)δ and p38 mitogen-activated protein kinase (p38 MAPK) on obesity-related glomerulopathy. Design and Methods: Male Wistar rats were randomly assigned to standard laboratory chow or a high-fat diet for 32 weeks. Glomerular mesangial cells HBZY-1 and mature differentiation 3T3-L1 cells were cocultured and were transfected with PPARδ-expressing vectors or treated with agonist or inhibitor of PPARδ or p38 MAPK. Results: Rats on a high-fat diet showed typical characteristics of metabolic syndrome including obesity, dyslipidemia, insulin resistance, and hypertension. Rats on a high-fat diet also had significant glomerular hypertrophy and extracellular matrix accumulation, which were accompanied by increased p38 MAPK phosphorylation and decreased PPARδ expression in the kidney tissue. The roles of p38 MAPK and PPARδ in a coculture system of mesangial cells and mature differentiation 3T3-L1 cells were further explored. PPARδ suppression promoted laminin and type IV collagen secretion through p38 MAPK phosphorylation in mesangial cells, whereas PPARδ overexpression or PPARδ agonist attenuated phosphorylation of p38 MAPK and laminin and type IV collagen secretion. Conclusions: The characteristics of obesity-related glomerulopathy, which might be partly caused by PPARδ suppression-induced p38 MAPK activation and laminin and type IV collagen secretion was demonstrated.

The mechanisms of the improvement of glucose homeostasis through angiotensin receptor blockers are not fully elucidated in hypertensive patients. We investigated the effects of telmisartan on insulin signaling and glucose uptake in cultured myotubes and skeletal muscle from wild-type and muscle-specific peroxisome proliferator–activated receptor (PPAR) δ knockout (MCK-PPARδ−/−) mice. Telmisartan increased PPARδ expression and activated PPARδ transcriptional activity in cultured C2C12 myotubes. In palmitate-induced insulin-resistant C2C12 myotubes, telmisartan enhanced insulin-stimulated Akt and Akt substrate of 160 kDa (AS160) phosphorylation as well as Glut4 translocation to the plasma membrane. These effects were inhibited by antagonizing PPARδ or phosphatidylinositol-3 kinase, but not by PPARγ and PPARα inhibition. Palmitate reducing the insulin-stimulated glucose uptake in C2C12 myotubes could be restored by telmisartan. In vivo experiments showed that telmisartan treatment reversed high-fat diet–induced insulin resistance and glucose intolerance in wild-type mice but not in MCK-PPARδ−/− mice. The protein levels of PPARδ, phospho-Akt, phospho-AS160, and Glut4 translocation to the plasma membrane in the skeletal muscle on insulin stimulation were reduced by high-fat diet and were restored by telmisartan administration in wild-type mice. These effects were absent in MCK-PPARδ−/− mice. These findings implicate PPARδ as a potential therapeutic target in the treatment of hypertensive subjects with insulin resistance.

c These authors contributed equally to this work Abstract Background/Aims: Age-related cerebrovascular dysfunction contributes to stroke, cerebral amyloid angiopathy, cognitive decline and neurodegenerative diseases. One pathogenic mechanism underlying this effect is increased oxidative stress. Up-regulation of mitochondrial uncoupling protein 2 (UCP2) plays a crucial role in regulating reactive oxygen species (ROS) production. Dietary patterns are widely recognized as contributors to cardiovascular and cerebrovascular disease. In this study, we tested the hypothesis that dietary curcumin, which has an antioxidant effect, can improve aging-related cerebrovascular dysfunction via UCP2 up-regulation. Methods: The 24-month-old male rodents used in this study, including male Sprague Dawley (SD) rats and UCP2 knockout (UCP2-/-) and matched wild type mice, were given dietary curcumin (0.2%). The young control rodents were 6-month-old. Rodent cerebral artery vasorelaxation was detected by wire myograph. The AMPK/UCP2 pathway and p-eNOS in cerebrovascular and endothelial cells were observed by immunoblotting. Results: Dietary curcumin administration for one month remarkably restored the impaired cerebrovascular endothelium-dependent vasorelaxation in aging SD rats. In cerebral arteries from aging SD rats and cultured endothelial cells, curcumin promoted eNOS and AMPK phosphorylation, up-regulated UCP2 and reduced ROS production. These effects of curcumin were abolished by either AMPK or UCP2 inhibition. Chronic dietary curcumin significantly reduced ROS production and improved cerebrovascular endothelium-dependent relaxation in aging wild type mice but not in aging UCP2-/- mice. Conclusions: Curcumin improves aging-related cerebrovascular dysfunction via the AMPK/UCP2 pathway.

Hypertension-induced renal fibrosis contributes to the progression of chronic kidney disease, and apigenin, an anti-hypertensive flavone that is abundant in celery, acts as an agonist of transient receptor potential vanilloid 4 (TRPV4). However, whether apigenin reduces hypertension-induced renal fibrosis, as well as the underlying mechanism, remains elusive. In the present study, the deoxycorticosterone acetate (DOCA)–salt hypertension model was established in male Sprague-Dawley rats that were treated with apigenin or vehicle for 4 weeks. Apigenin significantly attenuated the DOCA–salt-induced structural and functional damage to the kidney, which was accompanied by reduced expression of transforming growth factor-β1 (TGF-β1)/Smad2/3 signaling pathway and extracellular matrix proteins. Immunochemistry, cell-attached patch clamp and fluorescent Ca2+ imaging results indicated that TRPV4 was expressed and activated by apigenin in both the kidney and renal cells. Importantly, knockout of TRPV4 in mice abolished the beneficial effects of apigenin that were observed in the DOCA–salt hypertensive rats. Additionally, apigenin directly inhibited activation of the TGF-β1/Smad2/3 signaling pathway in different renal tissues through activation of TRPV4 regardless of the type of pro-fibrotic stimulus. Moreover, the TRPV4-mediated intracellular Ca2+ influx activated the AMP-activated protein kinase (AMPK)/sirtuin 1 (SIRT1) pathway, which inhibited the TGF-β1/Smad2/3 signaling pathway. In summary, dietary apigenin has beneficial effects on hypertension-induced renal fibrosis through the TRPV4-mediated activation of AMPK/SIRT1 and inhibition of the TGF-β1/Smad2/3 signaling pathway. This work suggests that dietary apigenin may represent a promising lifestyle modification for the prevention of hypertension-induced renal damage in populations that consume a high-sodium diet.

High salt intake is a major risk factor for hypertension. Although acute caffeine intake produces moderate diuresis and natriuresis, caffeine increases the blood pressure (BP) through activating sympathetic activity. However, the long-term effects of caffeine on urinary sodium excretion and blood pressure are rarely investigated. Here, we investigated whether chronic caffeine administration antagonizes salt sensitive hypertension by promoting urinary sodium excretion. Dahl salt-sensitive (Dahl-S) rats were fed with high salt diet with or without 0.1% caffeine in drinking water for 15 days. The BP, heart rate and locomotor activity of rats was analyzed and urinary sodium excretion was determined. The renal epithelial Na+ channel (ENaC) expression and function were measured by in vivo and in vitro experiments. Chronic consumption of caffeine attenuates hypertension induced by high salt without affecting sympathetic nerve activity in Dahl-S rats. The renal α-ENaC expression and ENaC activity of rats decreased after chronic caffeine administration. Caffeine increased phosphorylation of AMPK and decrease α-ENaC expression in cortical collecting duct cells. Inhibiting AMPK abolished the effect of caffeine on α-ENaC. Chronic caffeine intake prevented the development of salt-sensitive hypertension through promoting urinary sodium excretion, which was associated with activation of renal AMPK and inhibition of renal tubular ENaC.

High dietary salt-caused hypertension is associated with increasing reactive oxygen species generation and reduced nitric oxide (NO) bioavailability. Transient receptor potential vanilloid type 1 (TRPV1), a specific receptor for capsaicin, is proposed to be involved in Dahl salt-sensitive hypertension, as determined in acute or short-term experiments. However, it remains unknown whether activation of TRPV1 by dietary capsaicin could prevent the vascular oxidative stress and hypertension induced by a high-salt diet. Here, we report that consumption of a high-salt diet blunted endothelium-dependent relaxation in mesenteric resistance arteries and elevated nocturnal blood pressure in mice. These effects were associated with increased superoxide anion generation and reduced NO levels in mesenteric vessels in mice on a high-salt diet. However, chronic administration of capsaicin reduced the high-salt diet-induced endothelial dysfunction and nocturnal hypertension in part by preventing the generation of superoxide anions and NO reduction of mesenteric arteries through vascular TRPV1 activation. Our findings provide new insights into the role of TRPV1 channels in the long-term regulation of blood pressure in response to high-salt intake. TRPV1 activation through chronic dietary capsaicin may represent a promising lifestyle intervention in populations with salt-sensitive hypertension.

BACKGROUND Salt-induced vascular dysfunction in which underlying mechanisms involve reactive oxygen species (ROS)-mediated reduction of nitric oxide (NO) bioavailability has been well documented. Uncoupling protein 2 (UCP2) has been implicated in the vascular protection, specifically by decreasing ROS production. However, it is unclear how UCP2 affects vascular function in salt-loaded mice. METHODS UCP2-deficient (UCP2 -/- ) and wild-type (WT) mice were placed on either a normal-salt (NS, 0.5%) or a high-salt (HS, 8%) diet for 24 weeks. Blood pressure (BP), mesenteric arterial reactivity, superoxide production, and NO bioavailability in the intact vessels were measured in each group. RESULTS UCP2 -/- mice on a HS diet had a higher BP than those on a NS diet (P < 0.01). However, BP in WT mice was not different between the NS and HS diet group. Phenylephrine (PE)-induced contraction was enhanced while acetylcholine (ACh)-elicited relaxation was impaired in mesenteric resistance arteries from the HS diet-fed WT mice. Importantly, the enhanced contraction and impaired relaxation were both further exacerbated in UCP2 -/- mice. Similarly, the HS diet led to a moderate increase in superoxide production and a comparable decrease in NO availability in both aortas and mesenteric resistance vessels, and these effects were also remarkably enhanced in UCP2 -/- mice. CONCLUSIONS These findings suggest that UCP2 plays an important role in preventing salt-sensitive hypertension, which may be achieved by suppressing superoxide production and reserving NO bioavailability in blood vessels.

SummarySome plant-based diets lower the cardiometabolic risks and prevalence of hypertension. New evidence implies a role for the transient receptor potential vanilloid 1 (TRPV1) cation channel in the pathogenesis of cardiometabolic diseases. Little is known about impact of chronic TRPV1 activation on the regulation of vascular function and blood pressure. Here we report that chronic TRPV1 activation by dietary capsaicin increases the phosphorylation of protein kinase A (PKA) and eNOS and thus production of nitric oxide (NO) in endothelial cells, which is calcium dependent. TRPV1 activation by capsaicin enhances endothelium-dependent relaxation in wild-type mice, an effect absent in TRPV1-deficient mice. Long-term stimulation of TRPV1 can activate PKA, which contributes to increased eNOS phosphorylation, improves vasorelaxation, and lowers blood pressure in genetically hypertensive rats. We conclude that TRPV1 activation by dietary capsaicin improves endothelial function. TRPV1-mediated increase in NO production may represent a promising target for therapeutic intervention of hypertension.

This study investigates the sex difference of cardiometabolic risk profiles in subjects with visceral fat obesity (VFO) but normal waist circumference (WC). VFO, which is defined as visceral adipose tissue (VAT) area more than 100 cm(2) by computed tomography (CT), and cardiometabolic risk profiles were assessed in 437 subjects with normal WC (197 female subjects and 240 male subjects). The expression of adiponectin and its receptor in abdominal adipose tissue was measured in a subgroup of the subjects. Compared with the male subjects, female subjects had a larger abdominal subcutaneous adipose tissue (SAT) area (158+/-56 vs 116+/-38 cm(2), P0.01), smaller VAT area (67+/-44 vs 78+/-33 cm(2); P0.01), and lower prevalence of VFO (12.2 vs 24.2%, P0.001). This finding was accompanied by upregulated expressions of adiponectin and its receptor in abdominal adipose tissue in female subjects. Without VFO, the risk profiles were not significantly different between male subjects and female subjects. Although risk factors were increased and intensified in both sexes in the presence of VFO, female subjects with VFO were associated with greater cardiometabolic risks than male subjects. A regression analysis indicates the ratio of VAT/SAT for female subjects, whereas VAT and age for male subjects were independently associated with clustering of multiple cardiometabolic risk factors. In conclusion, in subjects with normal WC, the prevalence of VFO is lower and the expression of adiponectin and its receptor is higher in female subjects compared with male subjects. Although VFO was associated with increased risk in both sexes, the risk profile in female subjects with VFO was more pronounced.

Vasomotion describes oscillations of arterial vascular tone due to synchronized changes of intracellular calcium concentrations. Since increased calcium influx into vascular smooth muscle cells from spontaneously hypertensive rats (SHR) has been associated with variances of transient receptor potential canonical (TRPC) channels, in the present study we tested the hypothesis that increased vasomotion in hypertension is directly linked to increased TRPC expression. Using a small vessel myograph we observed significantly increased norepinephrine-induced vasomotion in mesenteric arterioles from SHR compared to normotensive Wistar–Kyoto (WKY) rats. Using immunoblottings we obtained significantly increased expression of TRPC1, TRPC3 and TRPC5 in mesenteric arterioles from SHR compared to WKY, whereas TRPC4 and TRPC6 showed no differences. Norepinephrine-induced vasomotion from SHR was significantly reduced in the presence of verapamil, SKF96365, 2-aminoethoxydiphenylborane (2-APB) or gadolinium. Pre-incubation of mesenteric arterioles with anti-TRPC1 and anti-TRPC3 antibodies significantly reduced norepinephrine-induced vasomotion and calcium influx. Control experiments with pre-incubation of TRPC antibodies plus their respective antigenic peptide or in the presence of anti-β-actin antibodies or random immunoglobulins not related to TRPC channels showed no inhibitory effects of norepinephrine-induced vasomotion and calcium influx. Administration of candesartan or telmisartan, but not amlodipine to SHR for 16 weeks significantly reduced either the expression of TRPC1, TRPC3 and TRPC5 as well as norepinephrine-induced vasomotion in mesenteric arterioles. In conclusion we gave experimental evidence that the increased TRPC1, TRPC3 and TRPC5 expression in mesenteric arterioles from SHR causes increased vasomotion in hypertension.

Taurine, the most abundant, semiessential, sulfur-containing amino acid, is well known to lower blood pressure (BP) in hypertensive animal models. However, no rigorous clinical trial has validated whether this beneficial effect of taurine occurs in human hypertension or prehypertension, a key stage in the development of hypertension. In this randomized, double-blind, placebo-controlled study, we assessed the effects of taurine intervention on BP and vascular function in prehypertension. We randomly assigned 120 eligible prehypertensive individuals to receive either taurine supplementation (1.6 g per day) or a placebo for 12 weeks. Taurine supplementation significantly decreased the clinic and 24-hour ambulatory BPs, especially in those with high-normal BP. Mean clinic systolic BP reduction for taurine/placebo was 7.2/2.6 mm Hg, and diastolic BP was 4.7/1.3 mm Hg. Mean ambulatory systolic BP reduction for taurine/placebo was 3.8/0.3 mm Hg, and diastolic BP was 3.5/0.6 mm Hg. In addition, taurine supplementation significantly improved endothelium-dependent and endothelium-independent vasodilation and increased plasma H 2 S and taurine concentrations. Furthermore, changes in BP were negatively correlated with both the plasma H 2 S and taurine levels in taurine-treated prehypertensive individuals. To further elucidate the hypotensive mechanism, experimental studies were performed both in vivo and in vitro. The results showed that taurine treatment upregulated the expression of hydrogen sulfide–synthesizing enzymes and reduced agonist-induced vascular reactivity through the inhibition of transient receptor potential channel subtype 3–mediated calcium influx in human and mouse mesenteric arteries. In conclusion, the antihypertensive effect of chronic taurine supplementation shows promise in the treatment of prehypertension through improvement of vascular function.

Background The prevalence of obesity has dramatically increased worldwide and has attracted rising attention, but the mechanism is still unclear. Previous studies revealed that transient receptor potential vanilloid 1 (TRPV1) channels take part in weight loss by enhancing intracellular Ca2+ levels. However, the potential mechanism of the effect of dietary capsaicin on obesity is not completely understood. Ca2+ transfer induced by connexin43 (Cx43) molecules between coupled cells takes part in adipocyte differentiation. Whether TRPV1-evoked alterations in Cx43-mediated adipocyte-to-adipocyte communication play a role in obesity is unknown. Materials and methods We investigated whether Cx43 participated in TRPV1-mediated adipocyte lipolysis in cultured 3T3-L1 preadipocytes and visceral adipose tissues from humans and wild-type (WT) and TRPV1-deficient (TRPV1-/-) mice. Results TRPV1 and Cx43 co-expressed in mesenteric adipose tissue. TRPV1 activation by capsaicin increased the influx of Ca2+ in 3T3-L1 preadipocytes and promoted cell lipolysis, as shown by Oil-red O staining. These effects were deficient when capsazepine, a TRPV1 antagonist, and 18 alpha-glycyrrhetinic acid (18α-GA), a gap-junction inhibitor, were administered. Long-term chronic dietary capsaicin reduced the weights of perirenal, mesenteric and testicular adipose tissues in WT mice fed a high-fat diet. Capsaicin increased the expression levels of p-CaM, Cx43, CaMKII, PPARδ and HSL in mesenteric adipose tissues from WT mice fed a high-fat diet, db/db mice, as well as obese humans, but these effects of capsaicin were absent in TRPV1-/- mice. Long-term chronic dietary capsaicin decreased the body weights and serum lipids of WT mice, but not TRPV1-/- mice, fed a high-fat diet. Conclusion This study demonstrated that capsaicin activation of TRPV1-evoked increased Ca2+ influx in Cx43-mediated adipocyte-to-adipocyte communication promotes lipolysis in both vitro and vivo. TRPV1 activation by dietary capsaicin improves visceral fat remodeling through the up-regulation of Cx43.

Background Disturbances in the regulation of cytosolic calcium concentration have been attributed to primary hypertension, but the role of calcium-permeable transient receptor potential canonical channel 3 (TRPC3) has not yet been evaluated in primary hypertension. Methods Expression of TRPC3 was determined using in-cell Western assay. Evaluation of RNA interference for the downregulation of a specific gene in cells by small interfering RNA was performed. Measurements of cytosolic calcium were carried out using the fluorescent dye fura2. Results Expression of TRPC3 was significantly increased in monocytes from spontaneously hypertensive rats (SHR) compared with normotensive Wistar-Kyoto rats (WKY). Transplasmamembrane calcium influx and thapsigargin-induced sustained calcium increase were significantly higher in SHR compared with WKY. In the presence of the TRP channel blocker SKF-96365 these differences were no longer observed. Specific TRPC3-knockdown by transfection of monocytes from SHR with small interfering RNA significantly reduced TRPC3 expression, trans–plasma membrane calcium influx, and thapsigargin-induced sustained calcium increase. Conclusions This study shows, for the first time, increased TRPC3 channel expression and increased TRPC3-related calcium influx in SHR.

Lowering blood pressure using thiazide-like diuretics, including chlorthalidone and hydrochlorothiazide, has been proven to be effective in clinical studies. However, the mechanisms by which thiazide-like diuretics lower blood pressure are still poorly understood. To evaluate whether thiazide-like diuretics cause calcium desensitization in smooth muscle cells, we measured their effects on agonist-induced increase of blood pressure in Wistar rats in vivo and on agonist-induced vasoconstriction of aortic rings, DNA synthesis, and protein synthesis, RhoA, Rho kinase, and intracellular calcium in vascular smooth muscle cells in vitro. Thiazide-like diuretics significantly attenuated angiotensin II–induced or norepinephrine-induced increase of systolic blood pressure in rats. Thiazide-like diuretics inhibited agonist-induced vasoconstriction of aortic rings in a concentration-dependent manner in the presence and absence of endothelium. The inhibitory effects of thiazide-like diuretics were similar to that of the specific Rho kinase inhibitor Y27632. RT-PCR and immunoblotting showed that RhoA and Rho kinase were significantly reduced in vascular smooth muscle cells after administration of thiazide-like diuretics. In contrast, thiazide-like diuretics did not affect protein tyrosine phosphatase-2 (SHP-2) expression. Agonist-induced changes of intracellular calcium were not affected by thiazide-like diuretics. The study indicates that thiazide-like diuretics inhibit agonist-induced vasoconstriction by calcium desensitization in smooth muscle cells linked to the Rho–Rho kinase pathway.

Objective: Taurine, the most abundant, semiessential, sulfur-containing amino acid, is well known to improve metabolic status in animal models. However, no rigorous clinical trial has validated whether this beneficial effect of taurine occurs in human, especially in prehypertensive participants. Design and Method: In this randomized, double-blind, placebo-controlled study, we assessed the effects of taurine intervention on metabolic parameters, such as blood pressure (BP) levels, carotid intima-media thickness (IMT), ankle brachial index (ABI)/toe brachial index (TBI), BMI and biochemical parameters in prehypertensive participants. We randomly assigned 120 eligible prehypertensive individuals to receive either taurine supplementation (1.6 g per day) or a placebo for 12 weeks. Then we further validated the results in spontaneously hypertensive rats (SHR), which were were intervented with 2% taurine water for 12 weeks. Results: Totally 97 participants completed the trial and no significant difference observed between the taurine and placebo groups. Taurine supplementation significantly decreased the clinic and 24-hour ambulatory BPs, especially in those with high-normal BP. In addition, taurine supplementation significantly improved endothelium-dependent and -independent vasodilation and reduced IMTs of these prehypertensive participants. Meanwhile taurine intervention increased plasma H2S and taurine concentrations. Other parameters did not change significantly upon taurine treatment compared with pre-treatment or placebo group. To further elucidate the mechanism, experimental studies were performed both in vivo and in vitro. The results showed that taurine treatment exerts hypotensive effects by upregulating the expressions of H2S-synthesizing enzymes and reducing agonist-induced vascular reactivity through the inhibition of TRPC3-mediated calcium influx in human and mouse mesenteric arteries. Also, taurine reduced ROS levels and improved mitochondrial respiratory fucntions in VSMCs from SHR compared with control group, thus inhibiting vascular remodeling pathways. Conclusions: Taurine supplementation improved vascular function of prehypertensive participants and SHRs by lowering BP levels and reducing IMT values. Taurine may become a new dietary factor improving the metabolic status in prehypertension.

High salt (HS) intake contributes to the development of hypertension. Epithelial sodium channels play crucial roles in regulating renal sodium reabsorption and blood pressure. The renal transient receptor potential vanilloid 1 (TRPV1) cation channel can be activated by its agonist capsaicin. However, it is unknown whether dietary factors can act on urinary sodium excretion and renal epithelial sodium channel (ENaC) function. Here, we report that TRPV1 activation by dietary capsaicin increased urinary sodium excretion through reducing sodium reabsorption in wild-type (WT) mice on a HS diet but not in TRPV1 –/– mice. The effect of capsaicin on urinary sodium excretion was involved in inhibiting αENaC and its related with-no-lysine kinase 1/serum- and glucocorticoid-inducible protein kinase 1 pathway in renal cortical collecting ducts of WT mice. Dietary capsaicin further reduced the increased αENaC activity in WT mice attributed to the HS diet. In contrast, this capsaicin effect was absent in TRPV1 –/– mice. Immunoprecipitation study indicated αENaC specifically coexpressed and functionally interact with TRPV1 in renal cortical collecting ducts of WT mice. Additionally, ENaC activity and expression were suppressed by capsaicin-mediated TRPV1 activation in cultured M1-cortical collecting duct cells. Long-term dietary capsaicin prevented the development of high blood pressure in WT mice on a HS diet. It concludes that TRPV1 activation in the cortical collecting ducts by capsaicin increases urinary sodium excretion and avoids HS diet–induced hypertension through antagonizing αENaC-mediated urinary sodium reabsorption. Dietary capsaicin may represent a promising lifestyle intervention in populations exposed to a high dietary salt intake.

High-salt diet-induced cardiac hypertrophy and fibrosis are associated with increased reactive oxygen species production. Transient receptor potential vanilloid type 1 (TRPV1), a specific receptor for capsaicin, exerts a protective role in cardiac remodeling that resulted from myocardial infarction, and peroxisome proliferation-activated receptorsδ(PPAR-δ) play an important role in metabolic myocardium remodeling. However, it remains unknown whether activation of TRPV1 could alleviate cardiac hypertrophy and fibrosis and the effect of cross-talk between TRPV1 and PPAR-δon suppressing high-salt diet-generated oxidative stress. In this study, high-salt diet-induced cardiac hypertrophy and fibrosis are characterized by significant enhancement of HW/BW%, LVEDD, and LVESD, decreased FS and EF, and increased collagen deposition. These alterations were associated with downregulation of PPAR-δ, UCP2 expression, upregulation of iNOS production, and increased oxidative/nitrotyrosine stress. These adverse effects of long-term high-salt diet were attenuated by chronic treatment with capsaicin. However, this effect of capsaicin was absent in TRPV1−/−mice on a high-salt diet. Our finding suggests that chronic dietary capsaicin consumption attenuates long-term high-salt diet-induced cardiac hypertrophy and fibrosis. This benefit effect is likely to be caused by TRPV1 mediated upregulation of PPAR-δexpression.

Objective: Obesity is global healthy problem. Uncoupling protein 1 (UCP1) mainly expresses on brown adipose tissue (BAT), uncouples energy substrate oxidation from mitochondrial ATP production and results in the loss of potential energy as heat. Transient receptor potential vanilloid subfamily, member 1 (TRPV1) is the heat-gated cation ion channel. The aim of this study was to investigate the in vivo role of TRPV1 and UCP1 co-action in obesity. Design and Method: We generated and characterized UCP1−/− mice lacking TRPV1 activity (TRPV1−/−/UCP1−/− mice). The core-body temperature and the locomotor activity were simultaneously measured by the telemetry system. The rate of mitochondrial respiration was measured using the Oxygraph-2k. Cytosol superoxide anion was determined by DHE and mitochondrial superoxide anion was measured by MitoSOX. The levels of ATP in primary cultured brown adipocytes were measured using a firefly luciferase-based ATP assay kit. Primary brown adipocytes were cultured and the fluorescence measurements of cells were made using a fluorescent plate reader. Results: TRPV1 and UCP1 double knockout would appear obesity in advance and more severe comparing with WT, TRPV1−/− and UCP1−/− mice. TRPV1 and UCP1 double knockout in mice reduced functional BAT generation to cause BAT white, and decreased lipolysis comparing with the other three groups. TRPV1−/−/UCP1−/− mice significantly decreased resting oxygen consumptions, heat production and locomotor activities. Mitochondrial respiratory function seriously disordered in BAT of TRPV1−/−/UCP1−/− mice. TRPV1 and UCP1 double knockout resulted in dramatically reduced Ca2+mito uptake in low [Ca2+]cyto that was coupled with H+mito extrusion, which affected ATP generation and oxidative stress in BAT mitochondria. TRPV1 knockout caused to a Ca2+mito uptake compensatory rise. Conclusions: The results of our genetic manipulation studies provide in vivo evidence for the pathogenesis of TRPV1 and UCP1 double knockout in mice caused obesity and offer a novel target to manipulate obesity and associated complications.

Type 2 diabetes mellitus (T2DM) is rapidly prevailing as a serious global health problem. Current treatments for T2DM may cause side effects, thus highlighting the need for newer and safer therapies. We tested the hypothesis that dietary capsaicin regulates glucose homeostasis through the activation of transient receptor potential vanilloid 1 (TRPV1)-mediated glucagon-like peptide-1 (GLP-1) secretion in the intestinal cells and tissues. Wild-type (WT) and TRPV1 knockout (TRPV1−/−) mice were fed dietary capsaicin for 24 weeks. TRPV1 was localized in secretin tumor cell-1 (STC-1) cells and ileum. Capsaicin stimulated GLP-1 secretion from STC-1 cells in a calcium-dependent manner through TRPV1 activation. Acute capsaicin administration by gastric gavage increased GLP-1 and insulin secretion in vivo in WT but not in TRPV1−/− mice. Furthermore, chronic dietary capsaicin not only improved glucose tolerance and increased insulin levels but also lowered daily blood glucose profiles and increased plasma GLP-1 levels in WT mice. However, this effect was absent in TRPV1−/− mice. In db/db mice, TRPV1 activation by dietary capsaicin ameliorated abnormal glucose homeostasis and increased GLP-1 levels in the plasma and ileum. The present findings suggest that TRPV1 activation–stimulated GLP-1 secretion could be a promising approach for the intervention of diabetes.

Recent studies have shown that atorvastain has anti-inflammatory effect and can prevent cardiac hypertrophy. The development of cardiac hypertrophy and dysfunction is associated with an increase in cardiac glucose utilization. In this study, we investigated the effect of atorvastatin on glucose oxidation in tumor necrosis factor α (TNF-α)-stimulated cardiomyocytes (H9c2 cells) and the potential role of peroxisome proliferation-activated receptor coactivator 1α (PGC-1α) in this effect. Exposure of H9c2 cells to TNF-α inhibited the expressions of PGC-1α, pyruvate dehydrogenase kinase 4, and carnitine palmityl transferase 1 and induced a significant increase in glucose oxidation rate. However, the effects of TNF-α were significantly reversed by atorvastatin. Selective silence of PGC-1α in H9c2 cells resulted in the downregulation of pyruvate dehydrogenase kinase 4 and carnitine palmityl transferase 1 and further increased the TNF-α-induced glucose oxidation. Interestingly, the effect of atorvastatin on PGC-1α was almost abolished by mevalonate and partially by farnesol but not by geranylgeraniol. In conclusion, atorvastatin inhibits TNF-α-induced glucose oxidation through PGC-1α upregulation in cardiomyocytes, which might be associated with the regulation of isoprenoid metabolites.

Nonalcoholic fatty liver is characterized by the fatty deformation and lipid deposition of hepatic parenchymal cells that are associated with cardiometabolic diseases. In this study, we report the effect of capsaicin on its receptor, transient receptor potential vanilloid 1 (TRPV1) cation channel, in preventing fatty liver formation. Functional TRPV1 has been detected in hepatocytes and liver tissues. TRPV1 activation by capsaicin reduced lipid accumulation and triglyceride level in the liver from wild-type (WT) mice. However, these effects were absent in the liver from TRPV1(-/-) mice. Chronic dietary capsaicin increased the hepatic uncoupling protein 2 (UCP2) expression in WT but not in TRPV1(-/-) mice (P 0.01). We conclude that TRPV1 long-time activation might prevent high-fat diet-induced fatty liver in mice through upregulation of hepatic UCP2. Dietary capsaicin may represent a promising intervention in populations at high risk for fatty liver.

Brown adipose tissue (BAT) is an energy-expending organ that produces heat. Expansion or activation of BAT prevents obesity and diabetes. Chronic cold exposure enhances thermogenesis in BAT through uncoupling protein 1 (UCP1) activation triggered via a β-adrenergic pathway. Here, we report that the cold-sensing transient receptor potential melastatin 8 (TRPM8) is functionally present in mouse BAT. Challenging brown adipocytes with menthol, a TRPM8 agonist, up-regulates UCP1 expression and requires protein kinase A activation. Upon mimicking long-term cold exposure with chronic dietary menthol application, menthol significantly increased the core temperatures and locomotor activity in wild-type mice; these effects were absent in both TRPM8(-/-) and UCP1(-/-) mice. Dietary obesity and glucose abnormalities were also prevented by menthol treatment. Our results reveal a previously unrecognized role for TRPM8, suggesting that stimulation of this channel mediates BAT thermogenesis, which could constitute a promising way to treat obesity.

Background and Purpose— Previous studies show that endothelial nitric oxide synthase (eNOS) plays a prominent role in maintaining cerebral blood flow and preventing stroke. Capsaicin in hot pepper can increase the phosphorylation of eNOS in endothelial cells. We test the hypothesis that chronic dietary capsaicin can prevent stroke through activation of cerebrovascular transient receptor potential vanilloid 1 (TRPV1) channels in stroke-prone spontaneously hypertensive rats (SHRsp). Methods— SHRsp were fed dietary capsaicin, and their onset of stroke was examined. TRPV1 knockout and transgenic mice were used for determining the function of TRPV1 channels. Expression of eNOS and cerebrovascular reactivity were examined. Results— Immunofluorescence showed TRPV1 channels and eNOS coexpression in cerebral arterioles. Administration of capsaicin significantly increased phosphorylated eNOS in carotid arteries from wild-type mice but not in TRPV1 knockout mice. Inhibition of eNOS using N G -nitro- l -arginine methyl ester, removal of endothelium, or mutant TRPV1 significantly reduced capsaicin-induced endothelium-dependent relaxation of basilar arteries in mice. Chronic dietary capsaicin also remarkably increased eNOS expression in carotid arteries from SHRsp. Compared with Wistar-Kyoto rats, SHRsp had impaired endothelium-dependent relaxation of basilar arteries. Administration of capsaicin or l -arginine significantly improved the endothelium-dependent relaxation of basilar arteries in SHRsp. SHRsp had hypertrophy of cerebral arterioles, which was reversed by dietary capsaicin. Importantly, long-term administration of capsaicin significantly delayed the onset of stroke and increased the survival time in SHRsp. Conclusions— Activation of TRPV1 channels by dietary capsaicin mediated increases in phosphorylation of eNOS and could represent a novel target for dietary intervention of stroke.

Aims Activation of transient receptor potential vanilloid type-1 (TRPV1) channels may affect lipid storage and the cellular inflammatory response. Now, we tested the hypothesis that activation of TRPV1 channels attenuates atherosclerosis in apolipoprotein E knockout mice (ApoE−/−) but not ApoE−/−TRPV1−/− double knockout mice on a high-fat diet. Methods and results Both TRPV1 mRNA and protein expression were identified in vascular smooth muscle cells (VSMC) and in aorta from C57BL/6J mice using RT–PCR, immunoblotting, and immunohistochemistry. In vitro , activation of TRPV1 by the specific agonists capsaicin and resiniferatoxin dose-dependently increased cytosolic calcium and significantly reduced the accumulation of lipids in VSMC from C57BL/6J mice but not from TRPV1−/− mice. TRPV1 activation increased ATP-binding cassette transporter A1 (ABCA1) expression and reduced low-density lipoprotein-related protein 1 (LRP1) expression in VSMC by calcium-dependent and calcineurin- and protein kinase A-dependent mechanisms. These results showed increased cellular cholesterol efflux and reduced cholesterol uptake. In vivo , long-term activation of TRPV1 by capsaicin for 24 weeks increased ABCA1 and reduced LRP1 expression in aorta from ApoE−/− mice on a high-fat diet. Long-term activation of TRPV1 significantly reduced lipid storage and atherosclerotic lesions in the aortic sinus and in the thoracoabdominal aorta from ApoE−/− mice but not from ApoE−/−TRPV1−/− mice on a high-fat diet. These findings indicated that TRPV1 activation ameliorates high-fat diet-induced atherosclerosis. Conclusion Activation of TRPV1 may be a novel therapeutic tool to attenuate atherosclerosis caused by a high-fat diet.