ABSTRACT
In order to clarify the potential role of calcium sensing receptor (CaSR), a typical G protein coupled receptor (GPCR), in hyperglacemia-induced macroangiopathy, experimental hyperglycemia models in vivo and in vitro were prepared. Firstly, SD rats were divided into control group (n=10) and diabetes group (n=10), and diabetic model was induced via high-fat diet feeding and streptozotocin (STZ, 30 mg/kg) injection. Hydroxyproline level, determined via Choramnie T oxidation method, in vessel wall in diabetic rats was 30% more than that in control group. The gene transcription and expression levels were detected by real-time PCR and Western blotting, respectively. Both of collagen I and III mRNA levels in diabetic aorta were nearly twice those in normal aorta. The cleaved caspase-3 and -9 were elevated 1.5 and 2.5 times respectively in diabetic vascular cells. As compared with controls, mRNA and protein levels of CaSR in aorta were increased by 3 and 1.5 times in diabetes group. The expression levels of Bax as well as pro-apoptotic kinases (phospho-p38 and phosphor-JNK) were also increased 2, 0.5 and 0.5 times respectively in diabetic rats. To further validate the involvement of CaSR in cell apoptosis and explore the potential mechanism, the endothelial cell line (human umbilical vascular endothelial cells, HUVECs) was stimulated with high concentration of glucose (33 mmol/L) to mimic hyperglycemia in vitro. Cell-based assays also showed that the CaSR level and key apoptotic proteins (cleaved caspase-3 and -9, Bax, phospho-p38 and phosphor-JNK) were elevated in response to stimulation, and inhibition of CaSR by using specific inhibitor (NPS-2143, 10 μmol/L) could protect cells against apoptosis. Our results demonstrated that CaSR might take important part in the development of diabetic macroangiopathy through promoting cell apoptosis induced by hyperglycemia.
ABSTRACT
In order to clarify the potential role of calcium sensing receptor (CaSR), a typical G protein coupled receptor (GPCR), in hyperglacemia-induced macroangiopathy, experimental hyperglycemia models in vivo and in vitro were prepared. Firstly, SD rats were divided into control group (n=10) and diabetes group (n=10), and diabetic model was induced via high-fat diet feeding and streptozotocin (STZ, 30 mg/kg) injection. Hydroxyproline level, determined via Choramnie T oxidation method, in vessel wall in diabetic rats was 30% more than that in control group. The gene transcription and expression levels were detected by real-time PCR and Western blotting, respectively. Both of collagen I and III mRNA levels in diabetic aorta were nearly twice those in normal aorta. The cleaved caspase-3 and -9 were elevated 1.5 and 2.5 times respectively in diabetic vascular cells. As compared with controls, mRNA and protein levels of CaSR in aorta were increased by 3 and 1.5 times in diabetes group. The expression levels of Bax as well as pro-apoptotic kinases (phospho-p38 and phosphor-JNK) were also increased 2, 0.5 and 0.5 times respectively in diabetic rats. To further validate the involvement of CaSR in cell apoptosis and explore the potential mechanism, the endothelial cell line (human umbilical vascular endothelial cells, HUVECs) was stimulated with high concentration of glucose (33 mmol/L) to mimic hyperglycemia in vitro. Cell-based assays also showed that the CaSR level and key apoptotic proteins (cleaved caspase-3 and -9, Bax, phospho-p38 and phosphor-JNK) were elevated in response to stimulation, and inhibition of CaSR by using specific inhibitor (NPS-2143, 10 μmol/L) could protect cells against apoptosis. Our results demonstrated that CaSR might take important part in the development of diabetic macroangiopathy through promoting cell apoptosis induced by hyperglycemia.
Subject(s)
Animals , Humans , Rats , Diabetic Angiopathies , Human Umbilical Vein Endothelial Cells , Hyperglycemia , Receptors, Calcium-Sensing , PhysiologyABSTRACT
The aim of this study was to examine the effects of endoplasmic reticulum (ER) stress on aldosterone (Aldo)-induced apoptosis of endothelial cells. Glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP, a hallmark of ER-associated apoptosis) were used to evaluate ER stress. Western blotting and real-time PCR were used to analyze indicators of ER molecule. Apoptosis was detected by annexin V/propidium iodide staining and flow cytometry. Human umbilical vein endothelial cells (HUVECs) were stimulated with different concentrations of Aldo for different durations. Aldo promoted apoptosis of HUVECs and induced ER stress, as evidenced by increased expression of GRP78 and CHOP. siRNA knockdown of CHOP attenuated Aldo-mediated apoptosis. These results indicate that ER stress may be involved in Aldo-induced apoptosis of HUVECs.
ABSTRACT
The aim of this study was to examine the effects of endoplasmic reticulum (ER) stress on aldosterone (Aldo)-induced apoptosis of endothelial cells. Glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP, a hallmark of ER-associated apoptosis) were used to evaluate ER stress. Western blotting and real-time PCR were used to analyze indicators of ER molecule. Apoptosis was detected by annexin V/propidium iodide staining and flow cytometry. Human umbilical vein endothelial cells (HUVECs) were stimulated with different concentrations of Aldo for different durations. Aldo promoted apoptosis of HUVECs and induced ER stress, as evidenced by increased expression of GRP78 and CHOP. siRNA knockdown of CHOP attenuated Aldo-mediated apoptosis. These results indicate that ER stress may be involved in Aldo-induced apoptosis of HUVECs.
Subject(s)
Humans , Aldosterone , Pharmacology , Apoptosis , Endoplasmic Reticulum Stress , Gene Expression Regulation , Heat-Shock Proteins , Human Umbilical Vein Endothelial Cells , Cell Biology , Metabolism , Transcription Factor CHOPABSTRACT
<p><b>OBJECTIVE</b>To study erythrocyte oxidative stress status and its association with left to right shunt congenital heart disease (CHD) in children.</p><p><b>METHODS</b>A total of 31 children with left to right shunt CHD were enrolled, including 7 cases of atrial septal defect (ASD), 12 ventricular septal defect (VSD), 4 patent ductus arteriosus (PDA), 6 patent foramen ovale (PFO), and 2 complete endocardial cushion defect. Twenty healthy age-matched (1 month to 3 years old) children severed as the control group. The contents of superoxide dismutase (SOD) and malonaldehyde (MDA) in erythrocytes were determined using ELISA. ESR was measured by Westergen. PaO(2) and PaCO(2) were measured by Blood Gas Analyzer (GEM Premier 3000).</p><p><b>RESULTS</b>The MDA content in erythrocytes in the CHD group was significantly higher, in contrast, SOD content was significantly lower than that in the control group (P<0.05). The CHD children with heart failure had more decreased SOD and more increased MDA contents compared with the control group (P<0.01). The SOD level was the highest in the PFO group and was the lowest in the complete endocardial cushion defect group. The SOD level in the PFO group was significantly higher than that in the ASD, VSD and complete endocardial cushion defect groups (P<0.05). The MDA level was the highest in the VSD group and was the lowest in the complete endocardial cushion defect group. There were significant differences in the MDA level among CHD subgroups (P<0.05). The ESR was negatively correlated to the SOD level (r=-0.191, P<0.05), while positively correlated to PaO(2) level in CHD children (r=0.216, P<0.05). There was a negative correlation between SOD and MDA levels (r=-0.312, P<0.05).</p><p><b>CONCLUSIONS</b>Oxidative stress exists in children with left to right shunt CHD. The SOD and MDA contents in erythrocytes can be used as markers for the assessment of severity of the disease.</p>