Targeting PPARs for therapy of atherosclerosis: A review.

Atherosclerosis, a chief pathogenic factor of cardiovascular disease, is associated with many factors including inflammation, dyslipidemia, and oxidative stress. Peroxisome proliferator-activated receptors (PPARs) are nuclear receptors and are widely expressed with tissue- and cell-specificity. They control multiple genes that are involved in lipid metabolism, inflammatory response, and redox homeostasis. Given the diverse biological functions of PPARs, they have been extensively studied since their discovery in 1990s. Although controversies exist, accumulating evidence have demonstrated that PPAR activation attenuates atherosclerosis. Recent advances are valuable for understanding the mechanisms of action of PPAR activation. This article reviews the recent findings, mainly from the year of 2018 to present, including endogenous molecules in regulation of PPARs, roles of PPARs in atherosclerosis by focusing on lipid metabolism, inflammation, and oxidative stress, and synthesized PPAR modulators. This article provides information valuable for researchers in the field of basic cardiovascular research, for pharmacologists that are interested in developing novel PPAR agonists and antagonists with lower side effects as well as for clinicians.

CM3-SII polysaccharide obtained from Cordyceps militaris ameliorates hyperlipidemia in heterozygous LDLR-deficient hamsters by modulating gut microbiota and NPC1L1 and PPARα levels.

Accumulating evidence has demonstrated that polysaccharides derived from edible fungi have lipid-lowering effects in mice. However, the lipid metabolism mechanisms in mice and humans are different. We have previously elucidated the structural characteristics of the alkali-extracted polysaccharide CM3-SII obtained from Cordyceps militaris. This study aimed to investigate whether CM3-SII could ameliorate hyperlipidemia in a heterozygous low-density lipoprotein receptor (LDLR)-deficient hamster model of hyperlipidemia. Our data demonstrated that CM3-SII significantly decreased total plasma cholesterol, non-high-density lipoprotein cholesterol, and triglyceride levels in heterozygous LDLR-deficient hamsters. Unlike ezetimibe, CM3-SII could enhance the concentration of plasma apolipoprotein A1 and the expression of liver X receptor α/ATP-binding cassette transporter G8 mRNA pathway and suppress the expression of Niemann-Pick C1-like 1, which help to reduce cholesterol levels further. Moreover, the results of molecular docking analysis demonstrated that CM3-SII could directly bind to Niemann-Pick C1-like 1 with high affinity. The triglyceride-lowering mechanisms of CM3-SII were related to its downregulation of sterol regulatory element-binding protein 1c and upregulation of peroxisome proliferator-activated receptor α. Importantly, CM3-SII increased the abundance of Actinobacteria and Faecalibaculum and the ratio of Bacteroidetes/Firmicutes. Thus, CM3-SII attenuated hyperlipidemia by modulating the expression of multiple molecules involved in lipid metabolism and the gut microbiota.

Serum/glucocorticoid-inducible kinase 1 deficiency induces NLRP3 inflammasome activation and autoinflammation of macrophages in a murine endolymphatic hydrops model.

Ménière's disease, a multifactorial disorder of the inner ear, is characterized by severe vertigo episodes and hearing loss. Although the role of immune responses in Ménière's disease has been proposed, the precise mechanisms remain undefined. Here, we show that downregulation of serum/glucocorticoid-inducible kinase 1 is associated with activation of NLRP3 inflammasome in vestibular-resident macrophage-like cells from Ménière's disease patients. Serum/glucocorticoid-inducible kinase 1 depletion markedly enhances IL-1ß production which leads to the damage of inner ear hair cells and vestibular nerve. Mechanistically, serum/glucocorticoid-inducible kinase 1 binds to the PYD domain of NLRP3 and phosphorylates it at Serine 5, thereby interfering inflammasome assembly. Sgk-/- mice show aggravated audiovestibular symptoms and enhanced inflammasome activation in lipopolysaccharide-induced endolymphatic hydrops model, which is ameliorated by blocking NLRP3. Pharmacological inhibition of serum/glucocorticoid-inducible kinase 1 increases the disease severity in vivo. Our studies demonstrate that serum/glucocorticoid-inducible kinase 1 functions as a physiologic inhibitor of NLRP3 inflammasome activation and maintains inner ear immune homeostasis, reciprocally participating in models of Ménière's disease pathogenesis.

Targeting macrophages in atherosclerosis using nanocarriers loaded with liver X receptor agonists: A narrow review.

Macrophages are involved in the whole process of atherosclerosis, which is characterized by accumulation of lipid and inflammation. Presently, clinically used lipid-lowering drugs cannot completely retard the progress of atherosclerosis. Liver X receptor (LXR) plays a key role in regulation of lipid metabolism and inflammation. Accumulating evidence have demonstrated that synthetic LXR agonists can significantly retard the development of atherosclerosis. However, these agonists induce sever hypertriglyceridemia and liver steatosis. These side effects have greatly limited their potential application for therapy of atherosclerosis. The rapid development of drug delivery system makes it possible to delivery interested drugs to special organs or cells using nanocarriers. Macrophages express various receptors which can recognize and ingest specially modified nanocarriers loaded with LXR agonists. In the past decades, a great progress has been made in this field. These macrophage-targeted nanocarriers loaded with LXR agonists are found to decrease atherosclerosis by reducing cholesterol accumulation and inflammatory reactions. Of important, these nanocarriers can alleviate side effects of LXR agonists. In this article, we briefly review the roles of macrophages in atherosclerosis, mechanisms of action of LXR agonists, and focus on the advances of macrophage-targeted nanocarriers loaded with LXR agonists. This work may promote the potential clinical application of these nanocarriers.

Fenofibrate enhances lipid deposition via modulating PPARγ, SREBP-1c, and gut microbiota in ob/ob mice fed a high-fat diet.

Obesity is characterized by lipid accumulation in distinct organs. Presently, fenofibrate is a commonly used triglyceride-lowering drug. This study is designed to investigate whether long-term fenofibrate intervention can attenuate lipid accumulation in ob/ob mouse, a typical model of obesity. Our data demonstrated that fenofibrate intervention significantly decreased plasma triglyceride level by 21.0%, increased liver index and hepatic triglyceride content by 31.7 and 52.1%, respectively, and elevated adipose index by 44.6% compared to the vehicle group. As a PPARα agonist, fenofibrate intervention significantly increased the expression of PPARα protein in the liver by 46.3% and enhanced the expression of LDLR protein by 3.7-fold. However, fenofibrate dramatically increased the expression of PPARγ and SREBP-1c proteins by ~2.1- and 0.9-fold in the liver, respectively. Fenofibrate showed no effects on the expression of genes-related to fatty acid ß-oxidation. Of note, it significantly increased the gene expression of FAS and SCD-1. Furthermore, fenofibrate modulated the gut microbiota. Collectively, long-term fenofibrate induces lipid accumulation in liver and adipose tissues in ob/ob mice by enhancing the expression of adipogenesis-related proteins and gut microbiota. These data suggest that fenofibrate may have limited effects on attenuating lipid deposition in obese patients.

Structural Elucidation and Activities of Cordyceps militaris-Derived Polysaccharides: A Review.

Cordyceps militaris is a parasitic edible fungus and has been used as tonics for centuries. Polysaccharides are a major water-soluble component of C. militaris. Recently, C. militaris-derived polysaccharides have been given much attention due to their various actions including antioxidant, anti-inflammatory, anti-tumor, anti-hyperlipidemic, anti-diabetic, anti-atherosclerotic, and immunomodulatory effects. These bioactivities are determined by the various structural characteristics of polysaccharides including monosaccharide composition, molecular weight, and glycosidic linkage. The widespread use of advanced analytical analysis tools has greatly improved the elucidation of the structural characteristics of C. militaris-derived polysaccharides. However, the methods for polysaccharide structural characterization and the latest findings related to C. militaris-derived polysaccharides, especially the potential structure-activity relationship, have not been well-summarized in recent reviews of the literature. This review will discuss the methods used in the elucidation of the structure of polysaccharides and structural characteristics as well as the signaling pathways modulated by C. militaris-derived polysaccharides. This article provides information useful for the development of C. militaris-derived polysaccharides as well as for investigating other medicinal polysaccharides.

The polysaccharide-peptide complex from mushroom Cordyceps militaris ameliorates atherosclerosis by modulating the lncRNA-miRNA-mRNA axis.

An N-glycosidic polysaccharide-peptide complex CMPS-80 was obtained from the fruiting body of C. militaris. Of importance, CMPS-80 significantly ameliorated formation of atherosclerotic lesions and plasma lipid profiles in apolipoprotein E-deficient mice. Integrated informatics analysis suggested that CMPS-80 can modulate multiple lncRNA-microRNA-mRNA axes. CMPS-80 has a potential application for prevention of hyperlipidemia and atherosclerosis.

Propionate alleviates myocardial ischemia-reperfusion injury aggravated by Angiotensin II dependent on caveolin-1/ACE2 axis through GPR41.

Myocardial ischemia/reperfusion (I/R) injury is still a lack of effective therapeutic drugs, and its molecular mechanism is urgently needed. Studies have shown that the intestinal flora plays an important regulatory role in cardiovascular injury, but the specific mechanism has not been fully elucidated. In this study, we found that an increase in Ang II in plasma was accompanied by an increase in the levels of myocardial injury during myocardial reperfusion in patients with cardiopulmonary bypass. Furthermore, Ang II treatment enhanced mice myocardial I/R injury, which was reversed by caveolin-1 (CAV-1)-shRNA or strengthened by angiotensin-converting enzyme 2 (ACE2)-shRNA. The results showed that CAV-1 and ACE2 have protein interactions and inhibit each other's expression. In addition, propionate, a bacterial metabolite, inhibited the elevation of Ang II and myocardial injury, while GPR41-shRNA abolished the protective effects of propionate on myocardial I/R injury. Clinically, the propionate content in the patient's preoperative stool was related to Ang II levels and myocardial I/R injury levels during myocardial reperfusion. Taken together, propionate alleviates myocardial I/R injury aggravated by Ang II dependent on CAV-1/ACE2 axis through GPR41, which provides a new direction that diet to regulate the intestinal flora for treatment of myocardial I/R injury.

Screening and verification of CYP3A4 inhibitors from Bushen-Yizhi formula to enhance the bioavailability of osthole in rat plasma.

ETHNOPHARMACOLOGICAL RELEVANCE: With the features of multiple-components and targets as well as multifunction, traditional Chinese medicine (TCM) has been widely used in the prevention and treatment of various diseases for a long time. During the application of TCM, the researches about bioavailability enhancement of the bioactive constituents in formula are flourishing. Bushen-Yizhi formula (BSYZ), a TCM prescription with osthole (OST) as one of the main bioactive ingredients, have been widely used to treat kidney deficiency, mental retardation and Alzheimer's disease. However, the underlying biological mechanism and compound-enzyme interaction mediated bioavailability enhancement of OST are still not clearly illuminated. AIM OF THE STUDY: The aim of this study is to explore the material basis and molecular mechanism from BSYZ in the bioavailability enhancement of OST. Screening the potential CYP3A4 inhibitors using theoretical prediction and then verifying them in vitro, and pharmacokinetics study of OST in rat plasma under co-administrated of screened CYP3A4 inhibitors and BSYZ were also scarcely reported. MATERIALS AND METHODS: Screening of CYP3A4 inhibitors from BSYZ was performed with molecular docking simulation from systems pharmacology database. The screened compounds were verified by using P450-Glo Screening Systems. A multiple reaction monitoring (MRM) mass spectrometry method was established for OST quantification. Male Sprague-Dawley rats divided into four groups and six rats in each group were employed in the pharmacokinetics study of OST. The administrated conditions were group I, OST (20 mg/kg); group II, BSYZ (containing OST 1 mg/mL, at the dose of 20 mg/kg OST in BSYZ); group III, co-administration of ketoconazole (Ket, 75 mg/kg) and OST (20 mg/kg); group IV, co-administration of CYP3A4 inhibitor (10 mg/kg) and OST (20 mg/kg). They were determined by using HPLC-MS/MS (MRM) and statistical analysis was performed using student's t-test with p < 0.05 as the level of significance. RESULTS: 21 potential CYP3A4 inhibitors were screened from BSYZ compounds library. From the results of verification in vitro, we found 4 compounds with better CYP3A4 inhibition efficiency including Oleic acid, 1,2,3,4,6-O-Pentagalloylglucose, Rutin, and Schisantherin B. Under further verification, Schisantherin B exhibited the best inhibitory effect on CYP3A4 (IC50 = 0.339 µM), and even better than the clinically used drug (Ket) at the concentration of 5 µM. In the study of pharmacokinetics, the area under the curve (AUC, ng/L*h) of OST after oral administration of BSYZ, Ket and Schisantherin B (2196.23 ± 581.33, 462.90 ± 92.30 and 1053.03 ± 263.62, respectively) were significantly higher than that of pure OST treatment (227.89 ± 107.90, p < 0.01). CONCLUSIONS: Schisantherin B, a profoundly effective CYP3A4 inhibitor screened from BSYZ antagonized the metabolism of CYP3A4 on OST via activity inhibition, therefore significantly enhanced the bioavailability of OST in rat plasma. The results of this study will be helpful to explain the rationality of the compatibility in TCM formula, and also to develop new TCM formula with more reasonable drug compatibility.

Polysaccharide CM1 from Cordyceps militaris hinders adipocyte differentiation and alleviates hyperlipidemia in LDLR(+/-) hamsters.

BACKGROUND: Cordyceps militaris is cultured widely as an edible mushroom and accumulating evidence in mice have demonstrated that the polysaccharides of Cordyceps species have lipid-lowering effects. However, lipid metabolism in mice is significantly different from that in humans, making a full understanding of the mechanisms at play critical. METHODS: After 5 months, the hamsters were weighed and sampled under anesthesia after overnight fasting. The lipid-lowering effect and mechanisms of the polysaccharide CM1 was investigated by cellular and molecular technologies. Furthermore, the effect of the polysaccharide CM1 (100 µg/mL) on inhibiting adipocyte differentiation was investigated in vitro. RESULTS: CM1, a polysaccharide from C. militaris, significantly decreased plasma total cholesterol, triglyceride and epididymal fat index in LDLR(+/-) hamsters, which have a human-like lipid profile. After 5 months' administration, CM1 decreased the plasma level of apolipoprotein B48, modulated the expression of key genes and proteins in liver, small intestine, and epididymal fat. CM1 also inhibited preadipocyte differentiation in 3T3-L1 cells by downregulating the key genes involved in lipid droplet formation. CONCLUSIONS: The polysaccharide CM1 lowers lipid and adipocyte differentiation by several pathways, and it has potential applications for hyperlipidemia prevention.

The Cordyceps militaris-Derived Polysaccharide CM1 Alleviates Atherosclerosis in LDLR(-/-) Mice by Improving Hyperlipidemia.

Atherosclerotic cardiovascular disease has a high mortality worldwide. Our lab previously purified a polysaccharide designated as CM1 with (1→4)-ß-D-Glcp and (1→2)-α-D-Manp glycosyls as the backbone. In this study, we investigated the anti-atherosclerosis effect of CM1 and the underlying mechanisms of action in a low-density lipoprotein receptor knockout (LDLR(-/-) mouse model. It was found that CM1 significantly decreased the formation of atherosclerotic plaques. Mechanistically, CM1 enhanced plasma level of apolipoprotein A-I and decreased the plasma levels of triglyceride, apolipoprotein B, and total cholesterol. In the absence of LDLR, CM1 elevated the expression of very low-density lipoprotein receptor for liver uptake of plasma apolipoprotein B-containing particles and reduced hepatic triglyceride synthesis by inhibiting sterol regulatory element binding protein 1c. CM1 improved lipids excretion by increasing the liver X receptor α/ATP-binding cassette G5 pathway in small intestine. CM1 reduced lipogenesis and lipolysis by inhibiting peroxisome proliferator-activated receptor γ and adipose triglyceride lipase in epididymal fat. Furthermore, CM1 improved lipid profile in C57BL/6J mice. Collectively, CM1 can modulate lipid metabolism by multiple pathways, contributing to reduced plasma lipid level and formation of atherosclerotic plaques in LDLR(-/-) mice. This molecule could be explored as a potential compound for prevention and treatment of hyperlipidemia and atherosclerosis.

[Gnathology in implant-supported fixed restoration in edentulous mandible].

OBJECTIVE: This study aims to investigate the occlusal and myoelectric characteristics of implant-supported fixed denture in the mandibular region and provide reference for the design of fixed restoration. METHODS: Sixty edentulous patients with implant-supported fixed denture were selected and divided into three groups: group A, 20 cases with implant-supported fixed restoration in the maxillary region; group B, 20 cases with natural dentition, and group C, 20 cases with removable partial denture. The T-scan 8.0 digital occlusion analysis system was used to evaluate the occlusal characteristics of patients in the three groups at intercuspal, protrusion, and left and right lateral positions. Electromyography was used to analyze the myoelectric amplitude and bilateral asymmetry index of the anterior temporalis and masseter of the three groups in different states such as resting and clenching. The relationship between occlusion and myoelectricity was also investigated. RESULTS: In the occlusion analysis by T-scan, the occlusion time, the balance of left and right bite force, the left and right asymmetry of the occlusion center, the trajectory of central occlusion force, and the disclusion time were higher in group C than in groups A and B (P<0.05). No significant differences were observed in the anterior and posterior asymmetry of the occlusion center and percentage of bite force at anterior region among the three groups. In the analysis of myoelectricity, the myoelectric amplitude at resting state and the asymmetry index of masticatory muscles in group C were higher than those in groups A and B (P<0.05). The myoelectric amplitude during clenching in groups A and B groups was higher than that in group C (P<0.05). CONCLUSIONS: In implant-supported fixed restoration at edentulous mandibular, when maxillary includes the removable partial denture, degree of occlusal instability and left and right asymmetry of occlusion center are greater than those with the natural dentition and implant-supported fixed denture at maxillary. The myoelectricity is closely related to occlusion. The removable partial denture can increase the myoelectric activity and reduce the potential of the masticatory muscle. The asymmetry of bilateral myoelectricity is related to the occlusion imbalance.

Combined cross-linked enzyme aggregates of glycerol dehydrogenase and NADH oxidase for high efficiency in situ NAD+ regeneration.

Cofactor regeneration is an important method to avoid the consumption of large quantities of oxidized cofactor NAD+ in enzyme-catalyzed reactions. Herein, glycerol dehydrogenase (GDH) and NADH oxidase preparations by aggregating enzymes with ammonium sulphate followed by cross-linking formed aggregates for effective regeneration of NAD+. After optimization, the activity of combi-CLEAs and separate CLEAs mixtures were 950 and 580 U/g, respectively. And the catalytic stability of combi-CLEAs against pH and temperature was superior to the free enzyme mixture. After ten cycles of reuse, the catalytic efficiency could still retain 63.3% of its initial activity, indicating that the constructed combi-CLEAs system had excellent reusability. Also, the conversion of glycerol to 1,3-dihydroxyacetone (DHA) was improved by the constructed NAD+ regeneration system, resulting in 4.6%, which was 2.5 times of the free enzyme system. Thus, wide applications of this co-immobilization method in the production of various chiral chemicals could be expected in the industry for its high efficiency at a low cost.

Compound heterozygous mutation of MUSK causing fetal akinesia deformation sequence syndrome: A case report.

BACKGROUND: Fetal akinesia deformation sequence (FADS) is a broad spectrum disorder with absent fetal movements as the unifying feature. The etiology of FADS is heterogeneous and mostly still unknown. A prenatal diagnosis of FADS relies on clinical features obtained by ultrasound and fetal muscle pathology. However, the recent advances of next-generation sequencing (NGS) can effectively provide a definitive molecular diagnosis. CASE SUMMARY: A fetus presented after 24 wk and 6 d of gestation with absent fetal movements and multiple abnormal ultrasonographic signs. The mother had had a previous abortion due to a similarly affected fetus a year before. A clinical diagnosis of FADS was made. The parents refused cord blood examination and chose abortion. A molecular diagnosis of fetal muscle using NGS of genes found a compound heterozygous mutation in the MUSK gene: c.220C > T (chr9: 113449410 p.R74W) and c.421delC (chr9: 113457745 p.P141fs). CONCLUSION: To our knowledge, this is the first report in China showing that a mutation in MUSK is associated with FADS. This supports previous finding that a lethal mutation of MUSK will cause FADS. A precise molecular diagnosis for genetic counseling and options for a prenatal diagnosis of FADS are very important, especially for recurrent FADS; this may also provide evidence for both prenatal and preimplantation genetic diagnoses.

Is Waist-to-Height Ratio Superior to Body Mass Index and Waist Circumference in Predicting the Incidence of Hypertension?

BACKGROUND: It is still controversial which anthropometric indicator could be the best predictor of the incident hypertension. OBJECTIVES: To examine the relative power of body mass index (BMI), waist circumference (WC), skinfold thickness, waist-to-hip ratio (WHR), and waist-to-height ratio (WHTR) in predicting the incidence of hypertension in Chinese adults. METHOD: Data were obtained from the China Health and Nutrition Survey. Overweight was defined as BMI ≥23 kg/m2 and general obesity as BMI ≥27.5 kg/m2. Abdominal obesity was defined by WC values ≥90 cm for males and ≥80 cm for females. Skinfold thickness, WHR, and WHTR were divided into low and high groups according to receiver operating characteristics. Cox regressions and nomograms were employed to compare the relative power of 5 indicators in predicting incident hypertension. RESULTS: When all indicators were analyzed simultaneously, the best predictor of incident hypertension was general obesity (p < 0.001, adjusted hazard ratio [HR] 1.9, 95% CI 1.6-2.2). The results stratified by sex showed that BMI and WC were the more powerful predictors of hypertension in males (adjusted HR 1.8 and 1.3, 95% CI 1.4-2.3 and 1.1-1.5, respectively) as well as in females (adjusted HR 2.0 and 1.4, 95% CI 1.6-2.4 and 1.2-1.6, respectively). CONCLUSIONS: BMI and WC may predict incident hypertension better than skinfold thickness, WHR, and WHTR in the Chinese population.

Upregulated EFNB2 and EPHB4 promotes lung development in a nitrofen-induced congenital diaphragmatic hernia rat model.

Congenital diaphragmatic hernia (CDH) is a common congenital malformation associated with high mortality rates, mainly due to pulmonary hypoplasia and persistent pulmonary hypertension following birth. The present study aimed to investigate abnormal lung development in a rat CDH model, and examine temporal and spatial changes in the expression of ephrin type­B receptor 4 (EPHB4) and ephrin­B2 (EFNB2) during fetal lung development, to elucidate the role of these factors during lung morphogenesis. Pregnant rats received nitrofen on embryonic day (E) 8.5 to induce CDH, and fetal lungs were collected on E13.5, E15.5, E17.5, E19.5, and E21.5. The mean linear intercept (MLI) and mean alveolar number (MAN) were observed in fetal lung tissue at E21.5 following hematoxylin and eosin staining. E13.5 fetal lungs were cultured for 96 h in serum­free medium and branch development was observed under a microscope. The gene and protein expression levels of EPHB4 and EFNB2 were assessed by reverse transcription­quantitative polymerase chain reaction analysis, and immunoblotting and immunohistochemistry, respectively. The fetal rat lungs were treated with EFNB2 and the activity of key signaling pathways was assessed. The lung index (lung weight/body weight) at E21.5 was significantly lower in the CDH rats, compared with that in the control fetal rats. The MLI and MAN were also lower in the CDH group. The number of lung terminal buds at E13.5 (embryonic stage), and the lung­explant perimeter and surface were all smaller in the CDH group rats than in the control group at the same age. Pulmonary hypoplasia was observed following 96 h of in vitro culture. No significant differences were found in the expression levels of EFNB2 and EPHB4 between the CDH and control groups at E13.5 (embryonic stage) or E15.5 (pseudoglandular stage), however, EFNB2 and EPHB4 were significantly upregulated at E17.5 (canalicular stage), and at E19.5 and E21.5 (saccular/alveolar stages). EFNB2 stimulated pulmonary branching and EFNB2 supplementation decreased the activity of p38, c­Jun NH2­terminal kinase, extracellular signal­regulated kinase, and signal transducer and activator of transcription. The CDH fetal rats developed pulmonary dysplasia at an early stage of fetal pulmonary development. Upregulated expression of EFNB2 and EPHB4 was observed in the rat lung of nitrofen­induced CDH, and the increased expression of EFNB2 promoted rat lung development in the nitrofen­induced CDH model.

Nicotine Induces Cardiomyocyte Hypertrophy Through TRPC3-Mediated Ca2+/NFAT Signalling Pathway.

BACKGROUND: Nicotine is thought to be an important risk factor for the development of cardiovascular diseases. However, the effects of nicotine on cardiomyocyte hypertrophy are poorly understood. The present study was designed to explore the role of nicotine in cardiomyocyte hypertrophy and its underlying mechanism. METHODS: We used primary cardiomyocytes isolated from Wistar rats to examine the effects of nicotine on intracellular Ca2+ mobilization and hypertrophy determined by immunofluorescence, quantitative polymerase chain reaction, and western blot analysis. A luciferase reporter assay was used to examine the activity of NFAT signalling. RESULTS: We found that nicotine caused cardiomyocyte hypertrophy, which was accompanied by increased intracellular Ca2+. Nicotine-enhanced intracellular Ca2+ concentration ([Ca2+]i) was significantly abolished by store-operated Ca2+ entry (SOCE) and TRPC inhibitors. Knockdown of TRPC3 significantly decreased nicotine-induced SOCE and hypertrophy. Moreover, calcineurin-nuclear factor of activated T cells (NFAT) is involved in TRPC3-mediated Ca2+ signalling and cardiomyocyte hypertrophy. Notably, upregulation of TRPC3 by nicotine requires TRPC3-mediated Ca2+ influx and calcineurin-NFAT signalling activation. CONCLUSIONS: Our findings demonstrate that the prohypertrophic effect of nicotine on cardiomyocytes is dependent on enhanced TRPC3 expression through a calcium-dependent regulatory loop, which could become a potential target for prevention and treatment of cardiac hypertrophy.