OBJECTIVETo investigate the association between polymorphism of ATP2B1 gene, its interaction with smoking and susceptibility of essential hypertension.

METHODSA case-control study was conducted to elucidate the role of ATP2B1 gene variants related to the risk of essential hypertension. Genomic DNA was extracted from peripheral blood leukocytes, using the QIAamp DNA Mini Kit (QIAGEN,Germany). Two SNPs, - rs17249754 and rs6253, were examined on 1 280 patients and 1 010 healthy controls, using a Snapshot method. Statistical analyses were performed with SPSS Windows software (version 19.0;SPSS, Chicago, IL).

RESULTSA significant difference was found in rs17249754 allele frequency between cases and controls (OR = 1.223, 95%CI: 1.083-1.381, P = 0.001). After adjustment for age, sex, BMI, smoking and drinking, the difference was still statistically significant (OR = 1.212, 95%CI:1.070-1.373, P = 0.003). In addition, data from genotype distribution analysis under different models showed that appeared significant associations between ATP2B1 gene polymorphism and essential hypertension (additive model OR = 1.469, 95%CI: 1.121-1.925, P = 0.005; dominant model OR = 1.324, 95%CI:1.029-1.704, P = 0.029;recessive model OR = 1.123, 95%CI:1.031-1.223, P = 0.008). In this study, the proportion of smokers in cases was significantly higher than that in controls (P = 0.005), but no associations between rs17249754-smoking interaction and essential hypertension were found after the adjustment for gender, age, BMI and alcohol consumption (OR = 1.024, 95% CI:0.614-1.707).

CONCLUSIONOur research findings showed that the polymorphism of ATP2B1 gene rs17249754 was significantly associated with the incidence of essential hypertension in Han population of northeastern China. However, the interaction between rs17249754 and smoking did not seem to have contributed to the occurrence of the essential hypertension.

Aged ; Case-Control Studies ; Essential Hypertension ; Female ; Humans ; Hypertension ; etiology ; Male ; Middle Aged ; Plasma Membrane Calcium-Transporting ATPases ; genetics ; Polymorphism, Single Nucleotide ; Smoking

Intracellular Ca²⁺ mobilization is closely linked with the initiation of salivary secretion in parotid acinar cells. Reactive oxygen species (ROS) are known to be related to a variety of oxidative stress-induced cellular disorders and believed to be involved in salivary impairments. In this study, we investigated the underlying mechanism of hydrogen peroxide (H₂O₂) on cytosolic Ca²⁺ accumulation in mouse parotid acinar cells. Intracellular Ca²⁺ levels were slowly elevated when 1 mM H₂O₂ was perfused in the presence of normal extracellular Ca²⁺. In a Ca²⁺-free medium, 1 mM H₂O₂ still enhanced the intracellular Ca²⁺ level. Ca²⁺ entry tested using manganese quenching technique was not affected by perfusion of 1 mM H₂O₂. On the other hand, 10 mM H₂O₂ induced more rapid Ca²⁺ accumulation and facilitated Ca²⁺ entry from extracellular fluid. Ca²⁺ refill into intracellular Ca²⁺ store and inositol 1,4,5-trisphosphate (1 µM)-induced Ca²⁺ release from Ca²⁺ store was not affected by 1 mM H₂O₂ in permeabilized cells. Ca²⁺ efflux through plasma membrane Ca²⁺-ATPase (PMCA) was markedly blocked by 1 mM H₂O₂ in thapsigargin-treated intact acinar cells. Antioxidants, either catalase or dithiothreitol, completely protected H₂O₂-induced Ca²⁺ accumulation through PMCA inactivation. From the above results, we suggest that excessive production of H₂O₂ under pathological conditions may lead to cytosolic Ca²⁺ accumulation and that the primary mechanism of H₂O₂-induced Ca²⁺ accumulation is likely to inhibit Ca²⁺ efflux through PMCA rather than mobilize Ca²⁺ ions from extracellular medium or intracellular stores in mouse parotid acinar cells.
Acinar Cells* ; Animals ; Antioxidants ; Calcium ; Catalase ; Cell Membrane* ; Cytosol ; Dithiothreitol ; Extracellular Fluid ; Hand ; Hydrogen Peroxide* ; Hydrogen* ; Inositol 1,4,5-Trisphosphate ; Ions ; Manganese ; Mice* ; Perfusion ; Plasma Membrane Calcium-Transporting ATPases ; Plasma* ; Reactive Oxygen Species

The activation and deactivation of Ca(2+)- and calmodulindependent neuronal nitric oxide synthase (nNOS) in the central nervous system must be tightly controlled to prevent excessive nitric oxide (NO) generation. Considering plasma membrane calcium ATPase (PMCA) is a key deactivator of nNOS, the present investigation aims to determine the key events involved in nNOS deactivation of by PMCA in living cells to maintain its cellular context. Using time-resolved Förster resonance energy transfer (FRET), we determined the occurrence of Ca(2+)-induced protein-protein interactions between plasma membrane calcium ATPase 4b (PMCA4b) and nNOS in living cells. PMCA activation significantly decreased the intracellular Ca(2+) concentrations ([Ca(2+)]i), which deactivates nNOS and slowdowns NO synthesis. Under the basal [Ca(2+)]i caused by PMCA activation, no protein-protein interactions were observed between PMCA4b and nNOS. Furthermore, both the PDZ domain of nNOS and the PDZ-binding motif of PMCA4b were essential for the protein-protein interaction. The involvement of lipid raft microdomains on the activity of PMCA4b and nNOS was also investigated. Unlike other PMCA isoforms, PMCA4 was relatively more concentrated in the raft fractions. Disruption of lipid rafts altered the intracellular localization of PMCA4b and affected the interaction between PMCA4b and nNOS, which suggest that the unique lipid raft distribution of PMCA4 may be responsible for its regulation of nNOS activity. In summary, lipid rafts may act as platforms for the PMCA4b regulation of nNOS activity and the transient tethering of nNOS to PMCA4b is responsible for rapid nNOS deactivation.
Animals ; Brain ; metabolism ; Calcium ; metabolism ; Cells, Cultured ; Cerebellum ; cytology ; Fluorescence Resonance Energy Transfer ; HEK293 Cells ; Humans ; Nitric Oxide ; metabolism ; Nitric Oxide Synthase Type I ; metabolism ; PDZ Domains ; Plasma Membrane Calcium-Transporting ATPases ; metabolism ; Protein Interaction Maps ; Protein Isoforms ; metabolism ; Rats ; Rats, Sprague-Dawley