The Regulatory Role of H19/miR-181a/ATG5 Signaling in Perinatal Nicotine Exposure-Induced Development of Neonatal Brain Hypoxic-Ischemic Sensitive Phenotype

MicroRNA-124 negatively regulates STAT3 to alleviate hypoxic-ischemic brain damage by inhibiting oxidative stress

MicroRNA-124 (miR-124) is implicated in various neurological diseases; however, its significance in hypoxic-ischaemic brain damage (HIBD) remains unclear. This study aimed to elucidate the underlying pathophysiological mechanisms of miR-124 in HIBD. In our study performed on oxygen-glucose deprivation followed by reperfusion (OGD)/R-induced primary cortical neurons, a substantial reduction in miR-124 was observed. Furthermore, the upregulation of miR-124 significantly mitigated oxidative stress, apoptosis, and mitochondrial impairment. We demonstrated that miR-124 interacts with the signal transducer and activator of transcription 3 (STAT3) to exert its biological function using the dual-luciferase reporter gene assay. As the duration of OGD increased, miR-124 exhibited a negative correlation with STAT3. STAT3 overexpression notably attenuated the protective effects of miR-124 mimics, while knockdown of STAT3 reversed the adverse effects of the miR-124 inhibitor. Subsequently, we conducted an HIBD model in rats. In vivo experiments, miR-124 overexpression attenuated cerebral infarction volume, cerebral edema, apoptosis, oxidative stress, and improved neurological function recovery in HIBD rats. In summary, the neuroprotective effects of the miR-124/STAT3 axis were confirmed in the HIBD model. MiR-124 may serve as a potential biomarker with significant therapeutic implications for HIBD.

STZ-induced gestational diabetes exposure alters PTEN/AKT/mTOR-mediated autophagy signaling pathway leading to increase the risk of neonatal hypoxic-ischemic encephalopathy

Exposure to gestational diabetes mellitus (GDM) during pregnancy has significant consequences for the unborn baby and newborn infant. However, whether and how GDM exposure induces the development of neonatal brain hypoxia/ischemia-sensitive phenotype and the underlying molecular mechanisms remain unclear. In this study, we used a late GDM rat model induced by administration of streptozotocin (STZ) on gestational day 12 and investigated its effects of GDM on neonatal brain development. The pregnant rats exhibited increased blood glucose levels in a dose-dependent manner after STZ administration. STZ-induced maternal hyperglycemia led to reduced blood glucose levels in neonatal offspring, resulting in growth restriction and an increased brain to body weight ratio. Importantly, GDM exposure increased susceptibility to hypoxia/ischemia (HI)-induced brain infarct sizes compared to the controls in both male and female neonatal offspring. Further molecular analysis revealed alterations in the PTEN/AKT/mTOR/autophagy signaling pathway in neonatal male offspring brains, along with increased ROS production and autophagy-related proteins (Atg5 and LC3-II). Treatment with the PTEN inhibitor bisperoxovanadate (BPV) eliminated the differences in HI-induced brain infarct sizes between the GDM-exposed and the control groups. These findings provide novel evidence of the development of a brain hypoxia/ischemia-sensitive phenotype in response to GDM exposure and highlight the role of the PTEN/AKT/mTOR/autophagy signaling pathway in this process.

LncRNAs and CircRNAs as Strategies against Pathological Conditions Caused by a Hypoxic/Anoxic State

Brain damage can be induced by oxygen deprivation. It is known that hypoxic or anoxic conditions can lead to changes in the expression levels of non-coding RNAs (ncRNAs), which, in turn, can be related to Central Nervous System (CNS) injuries. Therefore, it could be useful to investigate the involvement of non-coding RNAs (ncRNAs), as well as the underlying mechanisms which are able to modulate them in brain damage induced by hypoxic or anoxic conditions. In this review, we focused on recent research that associates these conditions with long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). The results of this review demonstrate that the expression of both lncRNAs and circRNAs can be influenced by oxygen deprivation conditions and so they can contribute to inducing damage or providing neuroprotection by affecting specific molecular pathways. Furthermore, several experimental studies have shown that ncRNA activity can be regulated by compounds, thus also modifying their transcriptomic profile and their effects on CNS damages induced by hypoxic/anoxic events.

The role of microRNAs in nicotine signaling

Cigarette smoking is a harmful habit that is widespread around the world. It is among the well-known lifestyle-related risk factors for many diseases. Nicotine, as its principal constituent, has various detrimental, and beneficial functions. Nicotinic acetylcholine receptors (nAChRs), which are present in nearly all body cells, are how nicotine works. Numerous investigations have demonstrated that nicotine causes abnormal microRNA expression (miRNAs). These short sequences of RNAs are known to regulate gene expression post-transcriptionally. A wide range of miRNAs are modulated by nicotine, and nicotine-induced miRNA changes could subsequently mediate nicotine's effect on gene expression regulation. We will focus on the reciprocal interaction between nAChRs and miRNAs and describe the essential targets of these dysregulated miRNAs after nicotine exposure and activation of nAChRs. It appears that crucial subcellular mechanisms implicated in nicotine's effects are miRNA-related pathways. It is crucial to investigate the molecular mechanism underlying the effects of nicotine as well as the dysregulation of miRNA following nAChR activation. The finding about epigenetic mechanisms of nicotine-induced effects may shed light on the establishment of new treatment strategies to prevent the harmful effects of nicotine and perhaps may augment the beneficial effects in diverse smoking-related diseases.