A Polymorphism Of Matrix Gla Protein Is Associated With Risk Of Kidney Stone

Matrix Gla protein(MGP)plays a vital role in the calcification of extracellular matrix protein,which is significantly elevated during the abnormal calcification in the blood vessels and kidney.Many studies have been conducted to explore the vascular calcification and MGP was found to have a crucial function in the inhibition of vascular calcification.Kidney stones are a common complex disease with a high morbidity and recurrence rate,while the pathological mechanism is unclear so that effective prevention and treatments are still lacking.Calcium oxalate kidney stones is the most common kidney stones disease which shares many similar characteristics with the vascular calcification.Calcification-related proteins in the different formation process of calcification may play a similar role in the the calcification,the absence of calcification inhibition protein or functional changes will increase the risk of formation of calcification.Based on our preliminary work,we speculated that MGP might involve in suppressing the formation of calculus likely through affecting the interactions between crystals and epithelial cell of kidney tubules.We took kidney stone patients and healthy person's blood DNA as our study subject,and the relationship between MGP gene polymorphic variation and the onset risk of calcium oxalate kidney stones was detailedly explored.We first used blood genomic DNA extraction kit to extract human genome-wide DNA from whole blood,which were further performed by DNA agarose gel electrophoresis.The experimental results showed the successful extraction of the human genome-wide DNA.Long-PCR method was applied to obtain MGP gene from blood sample which including 26 cases of kidney stone patients and 28 healthy person,followed by identification of agarose gel electrophoresis.The electrophoresis results show that MGP gene was successful extracted.The MGP gene was further purified by gel extraction kit and performed gene sequencing,18 SNPs were classified through genotyping.5 'untranslated region(Untranslated Region UTR),exons and the 3'-UTR region of MGP gene were re-sequenced and classified by genotyping via gene sequencing,tag SNPs were identified,then ran by chain and correlation analysis.Results showed that among 18 SNPs of MGP registrated in database,only four SNPs were identified in our sample,including SNPrs1800802?SNPrs1800801?SNPrs4236 and SNPrs1049897,further studies found that there are no linkage and equilibrium among these tag SNPs,which did not constitute a haplotype.Relevant analysis found that SNPrs4236 allele(A/G)was correlated with the risk of onset of kidney stones.354 cases of kidney stone patients and 374 healthy people were choosed to further expand the sample.Allele-specific PCR was applied to genotype SNPrs4236.The correlation analysis showed that the occurrence rate of SNPrs236 G allele in healthy people was significantly higher than that in patients with kidney stones(OR 1.373,95%Cl 1.057-1.793,P = 0.019),suggesting that SNPrs4236 allele was correlated with the risk of onset of kidney stones.In conclusion,our research found for the first time that MGP gene polymorphic variation SNPrs4236 affect the onset risk of calcium oxalate kidney stones among Han in northeast China.