MicroRNA-210 knockdown contributes to apoptosis caused by oxygen glucose deprivation in PC12 cells

Role of miR-326 in neonatal hypoxic-ischemic brain damage pathogenesis through targeting of the δ-opioid receptor

Hypoxic-ischemic brain damage (HIBD) is a relatively common malignant complication that occurs in newborn infants, but promising therapies remain limited. In this study, we focused on the role of miR-326 and its target gene δ-opioid receptor (DOR) in the pathogenesis of neonatal HIBD. The expression levels of miR-326 and DOR after hypoxic-ischemic injury were examined both in vivo and in vitro. The direct relationship between miR-326 and DOR was confirmed by a dual-luciferase reporter assay. Further, effects of miR-326 on cell viability and apoptosis levels under oxygen glucose deprivation (OGD) were analyzed. The expression levels of miR-326 were significantly lower and DOR levels were significantly higher in the HIBD group than the control group both in vivo and in vitro. Overexpression of miR-326 downregulated the expression of DOR, while suppression of miR-326 upregulated the expression of DOR. The dual-luciferase reporter assay further confirmed that DOR could be directly targeted and regulated by miR-326. MiR-326 knockdown improved cell survival and decreased cell apoptosis by decreasing the expression levels of Caspase-3 and Bax and increasing Bcl-2 expression in PC12 cells after exposure to OGD. Moreover, DOR knockdown rescued the effect of the improved cell survival and suppressed cell apoptosis induced by silencing miR-326. Our findings indicated that inhibition of miR-326 may improve cell survival and decrease cell apoptosis in neonatal HIBD through the target gene DOR.

MicroRNA-210 contributes to peripheral nerve regeneration through promoting the proliferation and migration of Schwann cells

Peripheral nerve injury impacts the daily life of affected individuals. MicroRNA (miR)-210 is a multifunctional miR and has effects on the proliferation, migration and differentiation of cells. However, whether miR-210 has effects on peripheral nerve regeneration has remained elusive. In the present study, the miR-210 levels in a rat model of sciatic nerve injury were evaluated by reverse-transcription quantitative PCR and the effects of miR-210 on the proliferation and migration of Schwann cells were explored. Elevated miR-210 levels were discovered in the sciatic nerve injury rat model. miR-210 mimics were found to promote the proliferation and migration of Schwann cells, while miR-210 inhibitor was found to inhibit the proliferation and migration of Schwann cells. Further study showed that miR-210 had effects on the expression of growth-associated protein-43, myelin-associated glycoprotein and myelin basic protein. These results showed that miR-210 had effects on the proliferation and migration of Schwann cells and may be involved in the peripheral nerve regeneration.

MicroRNA-132 protects hippocampal neurons against oxygen-glucose deprivation-induced apoptosis

Hypoxic-ischemic brain injury (HIBI) results in death or long-term neurologic impairment in both adults and children. In this study, we investigated the effects of microRNA-132 (miR-132) dysregulation on oxygen-glucose deprivation (OGD)-induced apoptosis in fetal rat hippocampal neurons, in order to reveal the therapeutic potential of miR-132 on HIBI. MiR-132 dysregulation was induced prior to OGD exposure by transfection of primary fetal rat hippocampal neurons with miR-132 mimic or miR-132 inhibitor. The effects of miR-132 overexpression and suppression on OGD-stimulated hippocampal neurons were evaluated by detection of cell viability, apoptotic cells rate, and the expression of apoptosis-related proteins. Besides, TargetScan database and dual luciferase activity assay were used to seek a target gene of miR-132. As a result, miR-132 was highly expressed in hippocampal neurons following 2 h of OGD exposure. MiR-132 overexpression significantly increased OGD-diminished cell viability and reduced OGD-induced apoptosis at 12, 24, and 48 h post-OGD. MiR-132 overexpression significantly down-regulated the expressions of Bax, cytochrome c, and caspase-9, but up-regulated BCl-2. Caspase-3 activity was also significantly decreased by miR-132 overexpression. Furthermore, FOXO3 was a direct target of miR-132, and it was negatively regulated by miR-132. To conclude, our results provide evidence that miR-132 protects hippocampal neurons against OGD injury by inhibiting apoptosis.

Proliferation and motility of hepatocellular, pancreatic and gastric cancer cells grown in a medium without glucose and arginine, but with galactose and ornithine

Human primary hepatocytes are able to survive in a medium without glucose and arginine, but supplemented with galactose and ornithine (hepatocyte selection medium; HSM). To address the possibility of the application of HSM in cancer therapy, hepatocellular carcinoma cells, pancreatic cancer cells and gastric cancer cells were cultured in HSM. Cell proliferation was analyzed using an MTS assay. Morphological changes were analyzed using hematoxylin and eosin staining. Apoptosis was analyzed using a TUNEL assay and cell motility was assessed with a scratch assay. Cell proliferation was significantly suppressed in cell lines grown in HSM (P<0.01 in all the cell lines). Hematoxylin and eosin staining revealed pyknotic nuclei, suggesting that these cells had undergone apoptosis. The number of TUNEL-positive cells was significantly increased in HSM. In the scratch assay, the distance between the growing edge and the scratched edge was significantly lower (P<0.01 in all the cell lines) in cells cultured in HSM, compared with those grown in Dulbecco's modified Eagle's medium or RPMI-1640. Therefore, the proliferation and motility of hepatocellular carcinoma cells, pancreatic cancer cells and gastric cancer cells was suppressed, and these cells subsequently underwent apoptosis in a medium without glucose and arginine, but containing galactose and ornithine.

Temporal Profile of Circulating microRNAs after Global Hypoxia-Ischemia in Newborn Piglets

BACKGROUND

There is a lack of reliable biomarkers that can identify and grade acute hypoxic-ischemic encephalopathy in newborns. MicroRNAs (miRNA) are short, non-coding strands of RNA that are released into the circulation in response to tissue stress and injury. Some miRNAs are highly tissue specific and thus may potentially be non-invasive biomarkers of neonatal hypoxic-ischemic brain injury.

OBJECTIVE

The aim of this study was to characterize the temporal expression of selected circulating miRNAs in a clinically relevant piglet model of neonatal hypoxia-ischemia (HI).

METHODS

A total of 13 anesthetized newborn piglets were randomized to either a control group (n = 5) or transient global HI group (n = 8). HI was achieved by ventilation with 8% oxygen until the point of severe acidosis (arterial base excess ≤-20 mmol/l) and/or hypotension (mean arterial blood pressure ≤20 mm Hg) was reached. Plasma was sampled at baseline, at the end of HI and 0.5, 3.5 and 9.5 h after HI. MiRNA expression was measured by qRT-PCR.

RESULTS

Compared to baseline, miR-374a increased during HI (p = 0.01), remained elevated at 0.5 h after HI (p = 0.02) and was downregulated at 9.5 h after HI (p = 0.02). MiR-210 increased during HI (p = 0.02) and rapidly normalized by 0.5 h after HI. MiR-124 and miR-125b did not exhibit significant alterations. Correlations were observed between miR-374a, arterial pH, base excess and lactate levels, and between miR-210 and pO2 (p < 0.05).

CONCLUSIONS

Our data suggest that miR-374a and miR-210 are important regulators in neonatal HI and might have a place as biomarkers in this setting.