p22phox C242T Single-Nucleotide Polymorphism Inhibits Inflammatory Oxidative Damage to Endothelial Cells and Vessels.

BACKGROUND: The NADPH oxidase, by generating reactive oxygen species, is involved in the pathophysiology of many cardiovascular diseases and represents a therapeutic target for the development of novel drugs. A single-nucleotide polymorphism, C242T of the p22(phox) subunit of NADPH oxidase, has been reported to be negatively associated with coronary heart disease and may predict disease prevalence. However, the underlying mechanisms remain unknown. METHODS AND RESULTS: With the use of computer molecular modeling, we discovered that C242T single-nucleotide polymorphism causes significant structural changes in the extracellular loop of p22(phox) and reduces its interaction stability with Nox2 subunit. Gene transfection of human pulmonary microvascular endothelial cells showed that C242T p22(phox) significantly reduced Nox2 expression but had no significant effect on basal endothelial O2 (.-) production or the expression of Nox1 and Nox4. When cells were stimulated with tumor necrosis factor-α (or high glucose), C242T p22(phox) significantly inhibited tumor necrosis factor-α-induced Nox2 maturation, O2 (.-) production, mitogen-activated protein kinases and nuclear factor κB activation, and inflammation (all P<0.05). These C242T effects were further confirmed using p22(phox) short-hairpin RNA-engineered HeLa cells and Nox2(-/-) coronary microvascular endothelial cells. Clinical significance was investigated by using saphenous vein segments from non-coronary heart disease subjects after phlebotomies. TT (C242T) allele was common (prevalence of ≈22%) and, in comparison with CC, veins bearing TT allele had significantly lower levels of Nox2 expression and O2 (.-) generation in response to high-glucose challenge. CONCLUSIONS: C242T single-nucleotide polymorphism causes p22(phox) structural changes that inhibit endothelial Nox2 activation and oxidative response to tumor necrosis factor-α or high-glucose stimulation. C242T single-nucleotide polymorphism may represent a natural protective mechanism against inflammatory cardiovascular diseases.

Marine polychaete Namalycastis sp. extracts enhance proliferation and regeneration of mice 3T3 fibroblast and MCR-5 human fibroblast cells.

The Nereidid worm is a marine polychaete commonly found near the Nipa palm (Nypa fructicans) along the mangrove estuary. Recently, many usages have been documented for this polychaete family. Nevertheless, the true potentials of these marine worms, especially Namalycastis sp., from the medical perspective are still unknown. The current study investigated the cytotoxicity effect of Namalycastis sp. crude extracts on mice 3T3 fibroblast cells and human lung MRC-5 fibroblast cells. Thirteen concentrations (2, 4, 8, 16, 31, 63 µg/mL and 0.1, 0.3, 0.5, 1, 2, 4, 8 mg/mL) of the extracts were used as a treatment for 24 h, and cell viability was measured via the MTT assay. None of the 13 concentrations of Namalycastis sp. crude extracts showed cytotoxicity effects on the cell types investigated. However, based on the live images captured by the IncuCyte™ imaging system, the cells treated with Namalycastis sp. crude extracts showed an increased proliferation and growth rate in less than 10 h Furthermore, the extract concentration of 8 µg/mL induced the highest cell proliferation rate whereas 8 mg/mL led to the lowest cell proliferation rate following the treatment. Overall, Namalycastis sp. crude extracts were non-toxic on mice and human cells within the tested concentrations set. Still, it increased cell viability and proliferation compared with the control. This finding could pave the way for an alternative therapeutic strategy to treat debilitating disorders such as ageing, cardiovascular diseases, and neurodegenerative diseases.