LINC00665 knockdown protects against cerebral ischemia-reperfusion injury

LINC00665 has been reported to participate in several human diseases. However, the role of LINC00665 in cerebral ischemia-reperfusion (CI/R) is still unknown. This study is designed to investigate the role of LINC00665 in rats with CI/R injury. We established middle cerebral artery occlusion/ reperfusion (MCAO/R) rats model in vivo. PC12 cells treated with oxygen-glucose deprivation/reperfusion (OGD/R) were used to establish in vitro I/R model. RT-qPCR assay was adopted to assess the mRNA expression of LINC00665 and miR-744-5p. MTT assay was used to determine cell viability. The protein expression of Bax and Bcl-2 were detected by Western blot assay. The relationship between LINC00665 and miR-744-5p was confirmed by dual luciferase reporter assay and RNA immunoprecipitation (RIP). In this study, we found that LINC00665 was sharply up regulated in MCAO/R rats and PC12 cells treated with I/R. Functionally, LINC00665 knockdown attenuated oxidative damage in PC12 cells treated with I/R. Moreover, LINC00665 knockdown promoted cell viability, while inhibited cell apoptosis in PC12 cells treated with I/R. In addition, miR-744-5p was confirmed to be a target of LINC00665. LINC00665 knockdown was validated to project CI/R injury by sponging miR-744-5p expression.

MiR-877-5p suppresses cell growth, migration and invasion by targeting cyclin dependent kinase 14 and predicts prognosis in hepatocellular carcinoma

OBJECTIVE

Recent studies reveal that hepatocellular carcinoma (HCC) express aberrant microRNAs. Dysregulation of miR-877-5p has been observed in HCC. The objective of the present study was to explore the clinical significance, function and underlying mechanism of miR-877-5p in HCC.

PATIENTS AND METHODS

Quantitative reverse transcription PCR (qRT-PCR) was used to measure the levels of miR-877-5p in HCC specimens and HCC cell lines. Correlations between miR-877-5p expression and the clinicopathological features and prognosis of HCC patients were then evaluated. MTT assays, colony formation assays, scratch test, transwell assays were used to explore the biological function of miR-877-5p in HCC. A luciferase reporter assay and Western blot were conducted to confirm the target gene of miR-877-5p, and the results were validated in HCC cell lines.

RESULTS

We found that the expression of miR-877-5p was downregulated in HCC tissues or cell lines. Clinicopathologic analysis revealed that low miR-877-5p expression correlated with histologic grade (p = 0.008) and TNM stage (p = 0.018). The Kaplan-Meier method indicated that low miR-877-5p levels in HCC were associated with shorter overall survival (p = 0.0041) and disease-free survival (p = 0.0005). Multivariate analysis demonstrated that miR-877-5p expression was an independent poor prognostic factor for HCC patients. Functional assay revealed that upregulation of miR-877-5p could inhibit proliferation, migration, and invasion of HCC cells in vitro. We further identified cyclin-dependent kinase 14 (CDK14) as a direct target of miR-877-5p in HCC cells. Ectopic expression of CDK14 reversed the inhibitory effects of miR-877-5p.

CONCLUSIONS

Low miR-877-5p expression was a poor prognostic factor for HCC patients, and miR-877-5p functioned as a tumor suppressor in HCC cells via targeting CDK14.

Effect of different levels of protein concentrates supplementation on the growth performance, plasma amino acids profile and mTOR cascade genes expression in early-weaned yak calves

Objective

This study evaluated the effects of different levels of protein concentrate supplementation on the growth performance of yak calves, and correlated the growth rate to changes occurring in the plasma- amino acids, -insulin profile, and signaling activity of mammalian target of rapamycin (mTOR) cascade to characterize the mechanism through which the protein synthesis can be improved in early weaned yaks.

Methods

For this study, 48 early (3 months old) weaned yak calves were selected, and assigned into four dietary treatments according to randomized complete block design. The four blocks were balanced for body weight and sex. The yaks were either grazed on natural pasture (control diet) in a single herd or the grazing yaks was supplemented with one of the three protein rich supplements containing low (17%; LP), medium (19%; MP), or high (21%; HP) levels of crude proteins for a period of 30 days.

Results

Results showed that the average daily gain of calves increased (0.14 vs 0.23–0.26 kg; p<0.05) with protein concentrates supplementation. The concentration of plasma methionine increased (p<0.05; 8.6 vs 10.1–12.4 μmol/L), while those of serine and tyrosine did not change (p>0.05) when the grazing calves were supplemented with protein concentrates. Compared to control diet, the insulin level of calves increased (p<0.05; 1.86 vs 2.16–2.54 μIU/mL) with supplementation of protein concentrates. Addition of protein concentrates up-regulated (p<0.05) expression of mTOR-raptor, mammalian vacuolar protein sorting 34 homolog, the translational regulators eukaryotic translation initiation factor 4E binding protein 1, and S6 kinase 1 genes in both Longissimus dorsi and semitendinosus. In contrast, the expression of sequestosome 1 was down-regulated in the concentrate supplemented calves.

Conclusion

Our results show that protein supplementation improves the growth performance of early weaned yak calves, and that plasma methionine and insulin concentrations were the key mediator for gene expression and protein deposition in the muscles.

Intrasynaptosomal free calcium and nitric oxide metabolism in central nervous system oxygen toxicity

BACKGROUND

Central nervous system (CNS) oxygen (O2) toxicity is complex, and the etiology of its most severe manifestation, O2 convulsions, is yet to be determined. A role for nitric oxide (NO) has been proposed, although recent data have indicated that NO is synthesized from L-arginine by an enzyme, NO synthase (NOS). The enzyme is dependent on free calcium (Ca2+) concentration, therefore increases in intracellular Ca2+ may constitute the physiological and pathophysiological mechanisms for stimulating the synthesis of NO.

METHODS

In this study, the intrasynaptosomal free calcium concentration ([Ca2+]i) was measured by the fluorescence of fura-2/AM, and cGMP (as an indirect marker of NO levels) was by radioimmunoassay (RIA) in the rat hippocampus after hyperbaric oxygen (HBO) exposure. We also investigated the effects of daurisoline (DSL, calcium channel blocker) and N-nitro-L-arginine (LNNA, NOS inhibitor) on the above biochemical parameters and the development of oxygen toxicity.

RESULTS

The results show that when the rats were exposed to HBO at 0.5 MPa the intrasynaptosomal Ca2+ and cGMP levels increased by two and three times, respectively, whereas with the use of DSL prior to HBO, the accumulation of [Ca2+]i and cGMP dropped to 56% and 60%, correspondingly. In the rats medicated with LNNA prior to HBO. [Ca2+]i and cGMP levels dropped to 70% and 36% of the HBO group. At the same time, the appearance of CNS oxygen toxicity was delayed and the survival rate increased. The protective effects of LNNA were reversed by L-arginine pretreatment. These findings suggest that the neuronal Ca2+ overload during HBO exposure is a major factor in the pathogenesis of CNS O2 toxicity, and cGMP-NO pathways may be directly involved in HBO-induced seizures.

Alterations of G-protein coupling function in phosphoinositide signalling pathways of rat hippocampus by ischaemic brain injury

The activation of membrane-associated phospholipase C is rapidly and transiently induced in the central nervous system by a variety of stimuli. Ischaemic brain injury is one of the situations that leads to a dramatic increase in polyphosphoinositide (PPI) turnover. In this study, stimulation of PPI hydrolysis by glutamate (500 microM) was measured in hippocampal slices from rats up to 21 days after an ischaemic insult of 30 min. Ischaemia was induced using the four-vessel occlusion method. PPI hydrolysis elicited by glutamate was significantly increased in the slices prepared from ischaemic rats 24 h after reperfusion, the accumulation of inositol phosphates (InsPs) and inositol 1,4,5-trisphosphate (Insp3) was 614 +/- 74% (n = 8) and 182 +/- 11% (n = 9) of the basal level respectively. This potentiation was also observed 21 days after ischaemia. Hyper-responsiveness to glutamate was also accompanied by an increase in AIF4(-)-stimulated formation of [3H]inositol phosphates. In addition, global ischaemia did not change either high-affinity [3H]glutamate binding in hippocampal membranes or the stimulation of PPI hydrolysis by carbachol or noradrenaline in hippocampal slices. The present results suggest that the increased responsiveness to glutamate is the result, at least in part, of functional changes at the G-protein level, and may contribute to the pathophysiology of ischaemic brain injury or to the regenerative phenomena that accompany ischaemic damage.