F Zhang

Abstract Location-associated long noncoding RNA (lncRNA) was reported to interact with target protein via a cis- regulatory process especially for the Flank10kb class lncRNA. Based on this theory, we aimed to explore the regulatory mechanisms of Linc00974 and KRT19 (an lncRNA beyond the Flank10kb class with protein) when we first confirmed the aberrant expression in hepatocellular carcinoma in a previous study. Knockdown of Linc00974 resulted in an inhibition of cell proliferation and invasion with an activation of apoptosis and cell cycle arrest in vitro , which was also validated by a subcutaneous and tail vein/intraperitoneal injection xenotransplantation model in vivo . We further investigated the interaction pattern of Linc00974 and KRT19. MiR-642 was identified, by acting as the competing endogenous RNA in regulating Linc00974 and KRT19. Linc00974 was increased owing to an abnormal hypomethylation promoter, which induced the upregulation of KRT19 via ceRNA interaction, resulting in the activation of the Notch and TGF- β pathways as detected by cDNA microarray. We also discovered Linc00974F-1 stably expressed in the plasma. By the combined analysis of Linc00974F-1 with CYFRA21-1, we found that these joint indicators predicted growth and metastasis of tumor in HCC patients. In conclusion, the combination of Linc00974 and KRT19 may be novel indices for clinical diagnosis of tumor growth and metastasis in HCC, while Linc00974 may become a potential therapeutic target for the prevention of HCC progression.

Mesenchymal stem cells (MSCs) with elevated levels of connexin 43 (Cx43) have been shown to exhibit improved protection for ischemic hearts. However, it remains unclear whether Cx43 is involved in the paracrine actions of angiogenesis, the major mechanism of cell therapy. In the present study, an in vitro model with deprivation of oxygen and a murine myocardial infarction model with permanent ligation of the left anterior‑descending (LAD) coronary artery were used to determine whether gap junctions in MSCs promote angiogenesis. It was observed that MSCs that overexpressed Cx43 (MSCs‑Cx43), improve the cardiac function of infarcted myocardium as compared with control MSCs (MSCs‑vector) and MSCs with Cx43 knocked down by small interfering RNA (MSCs‑siCx43), accompanied with a reduction of infarct size and an increase in the vascular density and maturity. Increased levels of representative angiogenic factors [vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF)] were produced by MSCs‑Cx43 compared with MSCs‑siCx43 in vivo and in vitro. However, neither Cx43 formed gap junction specific inhibitor (Cx43 mimetic peptide) or gap junction opener (antiarrhythmic peptide) affected the production of VEGF and bFGF in MSCs under hypoxic stress. These data support the hypothesis that Cx43 in MSCs promotes angiogenesis in the infarcted heart, independent of gap junction formation.

We investigated the correlation between 5,10-methylenetetrahydrofolate reductase (MTHFR) gene methylation and pre-eclampsia, and its clinical significance, by comparing methylation in the MTHFR gene promoter of the placenta and peripheral venous blood in pre-eclampsia and normal gravidas. We enrolled 259 gravidas from the People's Liberation Army 202nd Hospital, China, between January 2011 and September 2011, including 127 pre-eclampsia and 132 nor-mal gravidas. Methylation levels of the MTHFR gene in placentas in two sets of gravidas were detected by methylation-specific polymerase chain reaction, plasma homocysteine levels were detected by enzyme-linked immunosorbent assay, and folic acid and vitamin B12 levels were detected by electrochemiluminescence. The chi-square test results were analyzed using the SPSS19.0 statistical software. In placentas, the methylation indices were 26.8% (34/127) and 15.2% (20/132) in the pre-eclampsia and normal groups, respectively (χ(2) = 5.30, P < 0.05, odds ratio (OR) = 2.04, 95% confidence interval (95%CI) = 1.10-3.73). In peripheral venous blood, the methylation indices were 22.8% (29/127) and 12.1% (16/132) in pre-eclampsia and normal groups, respectively (χ(2) = 5.17, P < 0.05, OR = 2.15, 95%CI = 1.11-4.15). The plasma methylation level of the pre-eclampsia group was consistent with the normal group. The plasma homocysteine level in the pre-eclampsia group was higher than in the normal group (P < 0.05). Levels of folic acid and vitamin B12 in the pre-eclampsia and normal groups were not statistically significant (P > 0.05). Patients with pre-eclampsia have hypermethylation in the MTHFR gene promoter, which may be one of its causes.