NALP3 Inflammasome Is Essential For Vascular Smooth Muscle Cells Calcification

Artery calcification is pathlogy change of calcium deposition in the artery wall.Once thought to result from passive precipitation of calcium and phosphate, it now appears that vascular calcification is a consequence of tightly regulated and active processes that culminate in organized extracellular matrix deposition by osteoblast-like cells. These cells may be derived from stem cells (circulating or within the vessel wall) or differentiation of existing cells, such as smooth muscle cells (SMCs) or pericytes. Several factors induce this transition, including bone morphogenetic proteins, oxidant stress, high phosphate levels, parathyroid hormone fragments, and vitamin D.Howere,many factors could infect this processes,including cytokines which induce vascular smooth muscle cell(VSMCs) into osteoblast, Osteoprotegerin (OPG) and osteopontin(OPN).Recently, the inflammasome in the host response to infection with various pathogens has been widely reported, however, the functions of inflammasome in vascular calcification is unknown.Here we show that nalp3 inflammasome was essential for vascular smooth muscle cells(VSMCs) calcification.Primary VSMCs was obtained from Human embryo and rat by plant method.and induced into calcification modelβ-glycerophosphate(β-GP).RT-PCR demostrated that the expression of nalp3 inflammasome increased at the early stage ofβ-glycerophosphate(β-GP) -induced RVSMC calcification,and RVSMC induced byβ-GP increased steady state of caspase-1 protein. The level of nalp3,ASC and caspase-1 mRNA is also increased in the arteries of rats treated with Vitamin D 30,000U/Kg-day for 3 days compared with vector treated control group. In the HVSMC calcification,RT-PCR and western blot also showed that nalp3 inflammasome was activated at the early stage of calcification.This results was further certified by il-1βElisa and immunofluorescence in which ASC protein redistribute from the nucleus to the cytoplasm. Further study proved that mRNA level of caspase-1 and OPG/RANKL degraded compared with control group at the early stage after supressed by caspase inhibitor ZVAD.fmk. Under these conditions, Alizarin Red S stain showed that calcification was improved after additon of ZVAD.fink. These results suggest that NALP3 inflammasome might affect VSMCs calcification through OPG/RANKL modulation.Otherwise,clinical pathlogy specimens showed that trascriptional level of nalp3 inflammasome was higher than control samples,and caspase-1 protein was increased in the pathlogy specimens.