| Object: VacA is one of the important virulence factors of Helicobacter pylori, our team has show that it can promote the degradation of important skeleton binding protein ezrin by mediating the inflow of extracellular calcium in cell experiments,and the degradation of ezrin affect the location progression of ACAP4 and proton pump on preietal cell membrane,causing gastric acid secretion capacity down-regulated.In order to verify the correctness of this conclusion and further reveal the role of ACAP4 - ezrin signaling pathways in gastric acid secretion, we extended the ideas from cell level to the animal level, ACAP4 specificially knockout mice was used to study the HP VacA effects on gastric acid secretion and to explore its mechanism.At the same time, we discuss the syndrome in patients with chronic gastritis via clinical investigation, analyses the evolution of chronic gastritis pathological change and its trends, and make use of the gastric mucosa tissue obtained from clinical patients to discuss the correlation between the expression of ACAP4 - ezrin, proton pump and pathological stage,and the correlation between syndrome characteristics,evolution trend and the protein expression has been discussed too.Methods:This study is divided into two parts contained a experimental study and a clinical research.The first part is an experimental study, using administration of Helicobacter pylori VacA toxin to ACAP4 knockout mice,gastric acid secretion, gastric mucous membrane susceptibility of VacA, effects of VacA on ACAP4 - ezrin and proton pump expression was assessed in order to reveal the important influence of ACAP4 - ezrin in gastric acid secretion and and the effects of VacA on the pathway.The second part is a clinical research, we collected diagnostic information of 300 cases of patients with chronic gastritis and 59 patients’gastric mucosa specimens,by using descriptive analysis, factor analysis was discussed the syndrome characteristics and its evolution trend,and combined with immunohistochemical methods, the corelationship between expression of ACAP4 -ezrin,proton pump and pathological evolution, and the correlation between protein expression and syndrome evolution was discussed too.Results: ① ACAP4 KO mice gastric acid secretion capacity reducted in physiological status, VacA can inhibit wild-type mice gastric acid secretion, but basically has no effect on acid secretion progression in ACAP4 KO mice.And gastric acid secretion levels mediated by gastrin in ACAP4 KO mice have increased compensatorily. ② The mucosal thickness and glandular structure disorders of wild-type mice is lighter than ACAP4 KO mice.In ACAP4 KO mice whith VacA administration,mucosal structure disorders, partial hemorrhage,and the pathological damage was significantly more serious than wild-type mice,and also the risk of vacuolization in epithelial cells is higher than wild-type mice.③VacA can obviously weakened the expression of ACAP4, ezrin and proton pump in normal gastric mucosa of wild-type mice.④The CSG patients have more excess syndromes, at the same time atrophic gastritis with more mingled deficiency and excess syndrome and the PLGC patients have more deficiency syndrome.These three stages have a trend of excess syndromes→termingled deficiency and excess syndromes→deficiency syndrome.⑤The expression of ACAP4 - ezrin and proton pump is obvious correlated with HP infection,but we temporarily not found significant correlation between their expression and the evolutive tendency.Conclusions:①ACAP4 - ezrin assume an important role in gastric acid secretion process, ACAP4 - ezrin mediated the gastric acid secretion can be blocked by ACAP4 knockout.②VacA damage ezrin positioning at the top of the parietal cell membrane and ACAP4-ezrin interactions still has a important function in gastric acid secretion declining in the overall level of animals.But the results of the experiment also indicated at the same time, in addition to ACAP4 - ezrin mediated gastric acid secretion pathway, there are still other pathways of gastric acid secretion.When the interaction of ACAP4 - ezrin is blocked, other pathways may be able to play the role of compensation.③After ACAP4 knockout,the mucosa injury susceptibility to VacA has increased,suggests ACAP4 - ezrin maybe an important targets of physiological dysfunction and pathological damage in gastric mucosa epithelial cells mediated by HP VacA.④ Experimental and clinical research show that the secreted VacA in HP infect process can act on ACAP4 -ezrin complex, destroy ezrin structure and suppress H,KATPase expression in a variety of ways, this may be one of the important mechanisms of hypoacidity mediated by HP infection in patients.⑤In chronic gastritis pathological evolution process,the expression of ACAP4,ezrin and proton pump declined with gastric mucosa structure damage increased gradually.The statistical results have demonstrated the expression of ACAP4,ezrin and proton pump have a certain correlation between chronic gastritis disease degree.Thus ACAP4 - ezrin and proton pump expressions are not only an important indexes in gastric acid secretion in parietal cell,but also maybe an important index of gastric mucosal lesion severity. ⑥ The CSG patients have more excess syndromes,at the same time atrophic gastritis with more mingled deficiency and excess syndrome and the PLGC patients have more deficiency syndrome.These three stages have a trend of excess syndromes→termingled deficiency and excess syndromes→ deficiency syndrome.⑦ There is an obvious pertinence between the expression of ACAP4-ezrin,proton pump and HP infection,but not a absolute negative relationship;and we temporarily not found a significant correlation between the expression of ACAP4-ezrin,proton pump and patients with chronic gastritis syndromes evolutive tendency. |
