The calcium-sensing receptor alleviates endothelial inflammation in atherosclerosis through regulation of integrin β1-NLRP3 inflammasome.

Atherosclerosis (AS) is a chronic inflammatory disease of arteries. Endothelial inflammation is key to the initiation and development of AS. The calcium-sensing receptor (CaSR) is expressed in endothelial cells (ECs) but its role in endothelial inflammation during AS remains unclear.

Impaired Iron-Sulfur Cluster Synthesis Induces Mitochondrial PARthanatos in Diabetic Cardiomyopathy.

Diabetic cardiomyopathy (DCM), a severe complication of diabetes, is characterized by mitochondrial dysfunction, oxidative stress, and DNA damage. Despite its severity, the intrinsic factors governing cardiomyocyte damage in DCM remain unclear. It is hypothesized that impaired iron-sulfur (Fe-S) cluster synthesis plays a crucial role in the pathogenesis of DCM.

DR1 Activation Inhibits the Proliferation of Vascular Smooth Muscle Cells through Increasing Endogenous HS in Diabetes.

Tissue ischemia and hypoxia caused by the abnormal proliferation of smooth muscle cells (SMCs) in the diabetic state is an important pathological basis for diabetic microangiopathy. Studies in recent years have shown that the chronic complications of diabetes are related to the decrease of endogenous hydrogen sulfide (HS) in diabetic patients, and it has been proven that HS can inhibit the proliferation of vascular SMCs (VSMCs). Our study showed that the endogenous HS content and the expression of cystathionine gamma-lyase (CSE), which is the key enzyme of HS production, were decreased in arterial SMCs of diabetic mice.

SKF38393 prevents high glucose (HG)-induced endothelial dysfunction by inhibiting the effects of HG on cystathionine γ-lyase/hydrogen sulfide activity and via a RhoA/ROCK1 pathway.

Background: Endothelial dysfunction plays a crucial role in diabetic vascular complications. A decrease in hydrogen sulfide (H2S) levels is increasingly becoming a vital factor contributing to high glucose (HG)-induced endothelial dysfunction. Dopamine D1-like receptors (DR1) activation has important physiological functions in the cardiovascular system.

DR1 activation promotes vascular smooth muscle cell apoptosis via up-regulation of CSE/H S pathway in diabetic mice.

The important role of hydrogen sulfide (H S) as a novel gasotransmitter in inhibiting proliferation and promoting apoptosis of vascular smooth muscle cells (VSMCs) has been widely recognized. The dopamine D1 receptor (DR1), a G protein coupled receptor, inhibits atherosclerosis by suppressing VSMC proliferation. However, whether DR1 contributes to VSMC apoptosis via the induction of endogenous H S in diabetic mice is unclear.

The DR1‑CSE/HS system inhibits renal fibrosis by downregulating the ERK1/2 signaling pathway in diabetic mice.

Glomerular mesangial cell (MC) proliferation and extracellular matrix deposition are the main pathological changes in diabetic nephropathy. Hydrogen sulfide (HS) inhibits the proliferation of MCs. Dopamine 1 receptors (DR1) are expressed in MCs and serve important physiological roles.

[Changes of myocardial function in diabetic rats and its mechanism].

Objective: To investigate the role of calcium-sensing receptor (CaSR) in the decrease of cardiac function in type 2 diabetic rats.

Methods: Wistar rats were randomly divided into 3 groups including control, diabetic-4 week and diabetic-8 week groups. Rats in the diabetes group were fed with high-glucose and high-fat diet, and intraperitoneal injection of streptozocin (STZ,30 mg/kg) was conducted 4 weeks later to establish a type 2 diabetes model.

NPS2390, a Selective Calcium-sensing Receptor Antagonist Controls the Phenotypic Modulation of Hypoxic Human Pulmonary Arterial Smooth Muscle Cells by Regulating Autophagy.

Background And Objectives: Calcium-sensing receptor (CaSR) is known to regulate hypoxia-induced pulmonary hypertension (HPH) and vascular remodeling via the phenotypic modulation of pulmonary arterial smooth muscle cells (PASMCs) in small pulmonary arteries. Moreover, autophagy is an essential modulator of VSMC phenotype. But it is not clear whether CaSR can regulate autophagy involving the phenotypic modulation under hypoxia.

Calcium-sensing receptor-mediated mitogen-activated protein kinase pathway improves the status of transplanted mouse embryonic stem cells in rats with acute myocardial infarction.

Several studies have identified the critical role of calcium-sensing receptors (CaSRs) in cardiac ischaemia/reperfusion injury and cardiac hypertrophy and have demonstrated that CaSRs induce myocardial apoptosis by activating MAPKs. Using acute myocardial infarction rat models, we found that a combination therapy of CaSR inhibition and embryonic stem cell (ESC) transplantation after acute myocardial infarction (AMI) leads to a dramatic reduction in the infarct size; a significant increase in the maximum rising and falling rate (+dp/dtmax and -dp/dtmax, respectively) of left ventricular pressure; a significant decrease in left ventricular end-diastolic pressure; a significant decrease in the mRNA expression level of CaSR, Bax, Bcl-2, cleaved caspase-3, cleaved caspase-9, p-ERK, p-JNK and p-P38 protein together with apoptosis indexes in the C and E groups; and a significant decrease in cTnT levels as well as LDH and CK activity. These findings indicate that cardiac function could be enhanced significantly by combination therapy with CaSR inhibition and ESC transplantation; the effect was better than ESC transplantation alone, and the mechanism might be associated with a reduction in cell apoptosis via the inhibition of the MAPK pathway.

Involvement of exogenous H2S in recovery of cardioprotection from ischemic post-conditioning via increase of autophagy in the aged hearts.

Background: Hydrogen sulfide (H2S), which is a member of the gasotransmitter family, plays an important physiological and pathological role in cardiovascular system. Ischemic post-conditioning (PC) provides myocardial protective effect in the young hearts but not in the aged hearts. Exogenous H2S restores PC-induced cardioprotection by inhibition of mitochondrial permeability transition pore (mPTP) in the aged hearts.

Exogenous spermine inhibits hypoxia/ischemia-induced myocardial apoptosis via regulation of mitochondrial permeability transition pore and associated pathways.

Myocardial infarction (MI) is associated with a high mortality rate, which is attributed to the effects of myocyte loss that occurs as a result of ischemia-induced cell death. Very few therapies can effectively prevent or delay the effects of ischemia. Polyamines (PAs) are polycations required for cell growth and division, and their use may prevent cell loss.

Exogenous H2S contributes to recovery of ischemic post-conditioning-induced cardioprotection by decrease of ROS level via down-regulation of NF-κB and JAK2-STAT3 pathways in the aging cardiomyocytes.

Background: Hydrogen sulfide (H2S), a third member of gasotransmitter family along with nitric oxide and carbon monoxide, generated from mainly catalyzed by cystathionine-lyase, possesses important functions in the cardiovascular system. Ischemic post-conditioning (PC) strongly protects against the hypoxia/reoxygenation (H/R)-induced injury and apoptosis of cardiomyocytes. However, PC protection is ineffective in the aging cardiomyocytes.

Exogenous spermine inhibits the proliferation of human pulmonary artery smooth muscle cells caused by chemically-induced hypoxia via the suppression of the ERK1/2- and PI3K/AKT-associated pathways.

Pulmonary vascular remodeling is a significant pathological feature of hypoxia-induced pulmonary hypertension (HPH), while pulmonary artery smooth muscle cell (PASMC) proliferation plays a leading role in pulmonary vascular remodeling. Spermine (Sp), a polyamine, plays a critical role in periodic cell proliferation and apoptosis. The present study was conducted to observe the association between hypoxia-induced PASMC proliferation and polyamine metabolism, and to explore the effects of exogenous Sp on PASMC poliferation and the related mechanisms.

Exogenous hydrogen sulfide restores cardioprotection of ischemic post-conditioning via inhibition of mPTP opening in the aging cardiomyocytes.

The physiological and pathological roles of hydrogen sulfide (H2S) in the regulation of cardiovascular functions have been recognized. H2S protects against the hypoxia/reoxygenation (H/R)-induced injury and apoptosis of cardiomyocytes, and ischemic post-conditioning (PC) plays an important role in cardioprotection from H/R injury in neonatal cardiomyocytes but not in aging cardiomyocytes. Whether H2S is involved in the recovery of PC-induced cardioprotection in aging cardiomyocytes is unclear.

[Decreased expression of calcium-sensing receptor involved in the progression of diabetic cardiomyopathy].

Objective: To observe the dynamic expression of calcium-sensing receptor(CaSR) in myocardium of diabetic rats.

Methods: Thirty male Wistar rats were randomly divided into 3 groups including control, diabetic-4 week and diabetic-8 week groups(n = 10). The type 2 diabetes mellitus models were established by intraperitoneal injection of streptozotocin (STZ, 30 mg/kg) after high-fat and high-sugar diet for one month.

Mediation of exogenous hydrogen sulfide in recovery of ischemic post-conditioning-induced cardioprotection via down-regulating oxidative stress and up-regulating PI3K/Akt/GSK-3β pathway in isolated aging rat hearts.

The physiological and pathological roles of hydrogen sulfide (H2S) in the regulation of cardiovascular functions have been recognized. Cystathionine gamma-lyase (CSE) is a major H2S-producing enzyme in cardiovascular system. Ischemic post-conditioning (PC) provides cadioprotection in young hearts but lost in the aging hearts.

Exercise training preserves ischemic preconditioning in aged rat hearts by restoring the myocardial polyamine pool.

Background: Ischemic preconditioning (IPC) strongly protects against myocardial ischemia reperfusion (IR) injury. However, IPC protection is ineffective in aged hearts. Exercise training reduces the incidence of age-related cardiovascular disease and upregulates the ornithine decarboxylase (ODC)/polyamine pathway.

Involvement of calcium-sensing receptors in hypoxia-induced vascular remodeling and pulmonary hypertension by promoting phenotypic modulation of small pulmonary arteries.

Phenotype modulation of pulmonary artery smooth muscle cells (PASMCs) plays an important role during hypoxia-induced vascular remodeling and pulmonary hypertension (PAH). We had previously shown that calcium-sensing receptor (CaSR) is expressed in rat PASMCs. However, little is known about the role of CaSR in phenotypic modulation of PASMCs in hypoxia-induced PAH as well as the underlying mechanisms.

Akt and Erk1/2 activate the ornithine decarboxylase/polyamine system in cardioprotective ischemic preconditioning in rats: the role of mitochondrial permeability transition pores.

Ornithine decarboxylase (ODC) is the first rate-limiting enzyme in polyamine biosynthesis, which is essential for cell survival. We hypothesized that the ODC/polyamine system is involved in ischemic preconditioning (IPC)-mediated cardioprotection through the activation of Erk1/2 and Akt and through the inhibition of the mitochondrial permeability transition (mPT). Isolated rat hearts were subjected to 40 min of ischemia either with or without IPC (3 cycles of 5-min global ischemia), and ODC protein expression, polyamine content, and Akt and Erk1/2 phosphorylation were evaluated after 30 min of reperfusion.

Mediation of dopamine D2 receptors activation in post-conditioning-attenuated cardiomyocyte apoptosis.

The physiological and pathological roles of dopamine D2 receptors (DR2) in the regulation of cardiovacular functions have been recognized. DR2 activation protects hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury and apoptosis, and ischemic post-conditioning (PC) plays a critical role in cardioprotection as well; however the involvement of the DR2 activation in the PC-induced cardioprotection is unknown. In the present study, we found that the H/R increased the expressions of DR2 mRNA and protein in cardiomyocytes, which were significantly enhanced by PC.

[The protective effect of DR2 activation on hypoxia/reperfusion injury in the neonatal rat cardiomyocytes and related mechanism].

Objective: To observe the effect of dopamine receptor (DR2) activation on hypoxia/reperfusion injury (HRI) in the neonatal rat cardiomyocytes, and to explore its mechanism.

Methods: The hypoxia/reperfusion (H/R) injury model was established in primarily cultured neonatal rat cardiomyocytes, and randomly assigned: control, H/R, bromocriptine (Bro) and haloperidol (Hal) groups. The cell apoptosis was detected using inverted microscope, transmission electron microscope and flow cytometry (FCM).

Involvement of dopamine D2 receptors activation in ischemic post-conditioning-induced cardioprotection through promoting PKC-ε particulate translocation in isolated rat hearts.

Dopamine D2 receptors (DR2) are important regulators in many organs, including cardiac system. Protein kinase C (PKC) activation and translocation is associated with cardioprotection against ischemic post-conditioning (PC); however, the regulatory role of DR2 during this process has been unknown. This study hypothesized that the prevention of cardiomyocyte damage by DR2 activation is associated with PKC translocation to the cell membrane.

The expression of calcium-sensing receptor in mouse embryonic stem cells (mESCs) and its influence on differentiation of mESC into cardiomyocytes.

The calcium-sensing receptor (CaSR), a G protein coupled receptor, is involved in a number of physiological and pathological processes. Embryonic stem cells (ESCs) have a potential role to differentiate into all types of cells. Whether CaSR is functionally expressed in ESCs is unclear.

Decrease in calcium-sensing receptor in the progress of diabetic cardiomyopathy.

To observe the dynamic expression of calcium-sensing receptor (CaSR) in myocardium of diabetic rats and explore its role in diabetic cardiomyopathy (DCM), 40 male Wistar rats were randomly divided into 4 groups including control, diabetic-4 weeks, diabetic-8 weeks and spermine treatment groups (240 μM of spermine in drinking water). The type 2 Diabetes mellitus (DM) models were established by intraperitoneal injection of streptozotocin (STZ, 30 mg/kg) after high-fat and high-sugar diet for one month. The echocardiographic parameters were measured, cardiac morphology was observed by electron microscope and HE staining.

Involvement of calcium-sensing receptor in oxLDL-induced MMP-2 production in vascular smooth muscle cells via PI3K/Akt pathway.

Matrix metalloproteinase-2 (MMP-2) is constitutively expressed in vascular smooth muscle cells (VSMCs) and up-regulated in atherosclerotic lesion by various stimuli, such as oxidized low-density lipoprotein (oxLDL). Calcium-sensing receptor (CaSR) is also expressed in VSMCs, but it remains unclear whether CaSR is associated with overproduction of MMP-2 in VSMCs. In this study, the expression of MMP-2 was detected by real-time PCR and Western blot analysis, and the gelatinolytic activity of MMP-2 was measured using gelatin zymography.