Identification of novel factors that affect the onset of idiopathic chronic pancreatitis: The role for microRNA-323b-5p.

BACKGROUND: The c.194+2 T>C variant of serine protease inhibitor Kazal type 1 (SPINK1) is a known genetic risk factor found in Chinese patients with idiopathic chronic pancreatitis (ICP), but the early-onset mechanisms of ICP are still unclear. METHODS: Complementary experimental approaches were used to pursue other potential pathologies in the present study. The serum level of SPINK1 of ICP patients in the Han population in China was detected and verified by an enzyme-linked immunosorbent assay. Next, differentially expressed proteins and microRNAs from plasma samples of early-onset and late-onset ICP patients were screened by proteomic analysis and microarray, respectively. RESULTS: Combined with these advanced methods, the data strongly suggest that the regulatory effects of microRNAs were involved in the early-onset mechanism of the ICP by in vitro experiments. There was no significant difference in the plasma SPINK1 expression between the early-onset ICP and the late-onset patients. However, the expression of plasma glutathione peroxidase (GPx3) in early-onset ICP patients was markedly lower than that in late-onset ICP patients, although the level of hsa-miR-323b-5p was lower in late-onset patients compared to the early-onset ICP group. In vitro experiments confirmed that hsa-miR-323b-5p could increase apoptosis in caerulein-treated pancreatic acinar cells and inhibit the expression of GPx3. CONCLUSIONS: The up-regulated hsa-miR-323b-5p might play a crucial role in the early-onset mechanisms of ICP by diminishing the antioxidant activity through the down-regulation of GPx3.

Cloning and sequence analysis of mosquito defensin genes.

OBJECTIVE: To clone the defensin genes from the Chinese main mosquito vectors and conduct sequnce analysis. METHODS: The genomic DNA and total RNA were extracted from Aedes aegypti, Aedes albopictus, Culex fatigans and Anopheles sinensis respectively, followed by PCR and reverse transcriptase-PCR with 2 pairs of primers designed and synthesized on the basis of reported defensin gene sequence. Purification and sequence analysis of the PCR products derived from the above procedure were conducted. RESULTS: The products with predicted size were amplified from the genomic DNA of A.aegypti, A.albopictus and A.sinensis. Sequence analysis showed that the amplified fragments from A.aegypti and A.albopictus, but not that from A.sinensis, were highly homologous with the reported defensin sequence. CONCLUSION: The defensin gene of A.aegypti and A.albopictus have been successfully cloned, and the homology of defensin genes among different mosquitoes is parallel to their genetic distances.