The role of miR-711 in cardiac cells in response to oxidative stress and its biogenesis: a study on H9C2 cells.

BACKGROUND: Oxidative stress results in cell apoptosis/death and plays a detrimental role in disease development and progression. Stressors alter the miRNA expression profile and miRNAs play a role in the cell response to stress. We previously showed that miR-711 is significantly over-expressed in extended cold ischemia reperfusion injured hearts in heart transplant. In this study, we aimed to investigate the role of miR-711 in cardiac cell damage in response to oxidative stress and how miR-711 is regulated. METHODS: Rat cardiac cell line H9c2 cells were cultured and exposed to oxidative conditions (Antimycin A (AA), H2O2, CoCl2, or cold hypoxia/reoxygenation (H/R)) in vitro. H9c2 cells were transfected with miR-711 mimics, miR-711 inhibitors, or small interference RNA, using transfection reagents. The expression of miR-711 was measured by quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR). Cell apoptosis/death was detected by flow cytometry and an IncuCyte system. Mitochondrial damage was detected by measuring the mitochondria membrane potential by flow cytometry. Gene expression was detected by qRT-PCR at the mRNA level and Western blotting and immunocytochemistry staining at the protein level. RESULTS: We found that miR-711 was significantly up-regulated in cells treated with H2O2, AA, CoCl2, and cold H/R. Over-expression of miR-711 increased cell apoptosis/death induced by AA and H/R whereas cell death was reduced by miR-711 inhibitors. MiR-711 induced cell death through negative regulation of angiopoietin 1 (Ang-1), fibroblast growth factor 14 (FGF14) and calcium voltage-gated channel subunit alpha1C (Cacna1c) genes. Both knockdown of hypoxia inducible factor 1α (HIF-1α) and inactivation of the nuclear factor kappa-light-chain-enhancer of activated B cells (NFКB) pathway inhibited over-expression of miR-711. CONCLUSION: Oxidative stress increases the expression of miR-711. Over-expression of miR-711 induces cell apoptosis/death. HIF-1α and NFКB regulate miR-711 in H9c2 cells during oxidative stress. miR-711 is a new target for preventing oxidative stress.

Plk2 Regulated by miR-128 Induces Ischemia-Reperfusion Injury in Cardiac Cells.

Ischemia-reperfusion (I/R) injury occurs during cardiac surgery and is the major factor leading to heart dysfunction and heart failure. Our previous study showed that gene and microRNA expression profiles are altered in heart grafts with extended I/R injury. In this study, we, for the first time, demonstrated that I/R injury upregulates the expression of Polo-like kinase 2 (Plk2) but decreases miR-128 expression in heart cells both in vitro and in vivo. Silencing Plk2 using small interfering RNA (siRNA) protects cells from Antimycin A-induced cell apoptosis/death. Silencing Plk2 also decreases phosphorylated p65 expression but increases Angiopoietin 1 expression. In addition, Plk2 is negatively regulated by miR-128. miR-128 exerts a protective effect on cell apoptosis similar to Plk2 siRNA in response to I/R stress. Methylation inhibitor 5-azacytidine (5-AZ) increases the expression of miR-128 and subsequently reduces Plk2 expression and cell apoptosis. In conclusion, this study demonstrated that Plk2 regulated by miR-128 induces cell apoptosis/death in response to I/R stress through activation of the nuclear factor κB (NF-κB) signal pathway. miR-128 and Plk2 are new targets for preventing cardiac I/R injury or oxidative stress-mediated injury.

Paternal and maternal genetic analysis of a desert Keriyan population: Keriyans are not the descendants of Guge Tibetans.

The Keriyan people live in an isolated village in the Taklimakan Desert in Xinjiang, Western China. The origin and migration of the Keriyans remains unclear. We studied paternal and maternal genetic variance through typing Y-STR loci and sequencing the complete control region of the mtDNA and compared them with other adjacent populations. Data show that the Keriyan have relatively low genetic diversity on both the paternal and maternal lineages and possess both European and Asian specific haplogroups, indicating Keriyan is an admixture population of West and East. There is a gender-bias in the extent of contribution from Europe vs. Asia to the Keriyan gene pool. Keriyans have more genetic affinity to Uyghurs than to Tibetans. The Keriyan are not the descendants of the Guge Tibetans.

Genetic diversities of cytochrome B in Xinjiang Uyghur unveiled its origin and migration history.

BACKGROUND: Uyghurs are one of the many populations of Central Eurasia that is considered to be genetically related to Eastern and Western Eurasian populations. However, there are some different opinions on the relative importance of the degree of Eastern and Western Eurasian genetic influence. In addition, the genetic diversity of the Uyghur in different geographic locations has not been clearly studied. RESULTS: In this study, we are the first to report on the DNA polymorphism of cytochrome B in the Uyghur population located in Xinjiang in northwest China. We observed a total of 102 mutant sites in the 240 samples that were studied. The average number of mutated nucleotides in the samples was 5.126. A total of 93 different haplotypes were observed. The gene diversity and discrimination power were 0.9480 and 0.9440, respectively. There were founder and bottleneck haplotypes observed in Xinjiang Uyghurs. Xinjiang Uyghurs are more genetically related to Chinese population in genetics than to Caucasians. Moreover, there was genetic diversity between Uyghurs from the southern and northern regions. There was significance in genetic distance between the southern Xinjiang Uyghurs and Chinese population, but not between the northern Xinjiang Uyghurs and Chinese. The European vs. East Asian contribution to the ten regional Uyghur groups varies among the groups and the European contribution to the Uyghur increases from north to south geographically. CONCLUSION: This study is the first report on DNA polymorphisms of cytochrome B in the Uyghur population. The study also further confirms that there are significant genetic differences among the Uyghurs in different geographical locations.

Reinstalling antitumor immunity by inhibiting tumor-derived immunosuppressive molecule IDO through RNA interference.

Tumor-derived immune suppression is a major impediment to successful immune/gene cancer therapy. In the present study, we describe a novel strategy to disrupt tumor-derived immune suppression by silencing a tolerogenic molecule of tumor origin, IDO, using small interfering RNA (siRNA). Silencing of IDO in B16F10 cells in vitro using IDO-siRNA prevented catabolism of tryptophan and inhibited apoptosis of T cells. IDO-siRNA treatment of B16F10 cells in vitro inhibited subsequent growth, tumor formation, and the size of tumor formed, by those cells when transplanted into host mice. In vivo treatment of B16F10 tumor-bearing mice successfully postponed tumor formation time and significantly decreased tumor size. Furthermore, in vivo IDO-siRNA treatment resulted in recovery of T cells responses and enhancement of tumor-specific killing. Thus, silencing IDO may break tumor-derived immune suppression. These data indicate that RNA interference has potential to enhance cancer therapy by reinstalling anticancer immunity.

Diabetes preventive gluten-free diet decreases the number of caecal bacteria in non-obese diabetic mice.

BACKGROUND: A gluten-free diet reduces the incidence of diabetes mellitus in non-obese diabetic (NOD) mice, but the mechanism is not known. The aim of this study was to examine the possible influence of the diet on the caecal bacterial flora, which may affect the intestinal physiology and mediate disease prevention. METHODS: Two groups of NOD mice from the age of 3 weeks were fed either a gluten-free diet or a standard diet. Each diabetic mouse, when diagnosed, along with a non-diabetic mouse from the same diet group and two non-diabetic mice from the alternate diet group were euthanized and sampled for classical bacteriological examination. RESULTS: Nine out of 19 (47%) standard-fed mice and 1 out of 19 (5%) gluten-free-fed mice developed diabetes (p < 0.01). Mice on the gluten-free diet had significantly fewer aerobically (p < 0.01) and microaerophilically (p < 0.001) cultivated bacteria in their intestines than standard-fed mice. Non-diabetic mice also had significantly fewer microa erophilic and anaerobic bacteria than diabetic mice (p < 0.05). These differences were primarily due to a difference in the Gram-positive flora. CONCLUSIONS: The gluten-free diet compared to the standard diet both qualitatively and quantitatively substantially altered the composition of the caecal bacterial flora in NOD mice. Although Gram-positive bacteria might influence the beta cells through certain digestive products, it is more likely to assume that any effect on diabetes incidence is immunological.