Essential Role Of TRPC6 Channels In The Pathogenesis Of Barrett's Esophagus

Objective: Barrett's esophagus(BE)is defined as metaplastic conversion of esophageal squamous epithelium to intestinalized columnar epithelium.Until now,The Barrett's esophagus is a complication of chronic gastroesophageal reflux disease(GERD)and recognized as premalignant lesion of esophageal adenocarcinoma(EAC).The potential of risk of BE patient develop to the EAC is 30 to 50 times higher than the normal person[1].At present,the antisecretory medication was used to cure of GRED,and reduce the risk of BE.This data indicated that the acid stimulation play an important role in the development of BE.However,the molecular of mechanism of BE is unclear.In this study,the role of acid stimulation in the development of BE was investigated,and provide theoretical basis for clinical prophylaxis and therapy of BE.Methods:1.The intracellular Ca2+ concentration in SHEE cells were recorded after treated with different pH solution and different inhibitors by the calcium imaging system.2.The protein expression of CDX2 and TRPC6 in lower esophageal mucosa between normal person and BE patient were analyzed by the immunohistochemistry technique. Further,the correlation between CDX2 and TRPC6 in Barrett's esophagus were analyzed.3.The protein expression of CDX2 and TRPC6 in HEEC cell line were detected by Western-Bolt after application of acidic buffer solution for 24 hours.Results:1.The calcium data showed that the solution of pH7.0?pH6.5?pH6.0 failed to evaluate the intracellular calcium increase in SHEE cells(P>0.05).The intracellular calcium signaling of SHEE cells was significantly increased after treated with pH5.5 and pH5.0 (P<0.05).Further,The calcium response was inhibited,after application of inhibitor BAPTA-AM(an intracellular calcium chelator)and SKF96365 a specific blocker of TRPC6.2.The protein expression of CDX2 and TRPC6 in BE patient were higher than the normal person(P<0.05).Moreover,the expression of CDX2 was significantly correlated with the levels of TRPC6 in the same BE patient tissues.3.The protein expression of CDX2 and TRPC6 were significantly increased compare to the control group after treated with acid solution(pH5.5)for 24 hours.The protein expression of CDX2 and TRPC6 were completely suppressed after treated with BAPTA-AM and SKF96365 in HEEC cell(P<0.05).Conclusion: Acid exposure promotes the genesis of Barrett esophagus by activating TRPC6,rising the level of intracellular Ca2+ level and enhancing the expression of CDX2.