Silencing of Long Noncoding RNA GAS5 Blocks Experimental Cerebral Ischemia-Reperfusion Injury by Restraining AQP4 Expression via the miR-1192/STAT5A Axis

The Roles of Non-coding RNA Targeting Astrocytes in Cerebral Ischemia

Astrocytes are key targets for treating cerebral ischemia in the central nervous system. Non-coding RNAs (ncRNAs) participate in the pathological processes of astrocytes in cerebral ischemia. Recent reports suggest that ncRNAs ameliorate the outcome of cerebral ischemia by mediating astrocytes' inflammatory reaction, oxidative stress, excitotoxicity, autophagy, and apoptosis. Reconstructing cellular systems might offer a promising strategy for treating cerebral ischemia. This review briefly discusses the potential of ncRNAs as drug targets and explores the molecular regulatory mechanisms through which ncRNAs target astrocytes in cerebral ischemia. It provides an overview of the current research, discusses ncRNAs' implications as clinical markers for cerebral ischemia, and anticipates that ongoing research on ncRNAs may contribute to novel therapeutic approaches for treating this condition.

Multicenter Validation of lncRNA and Target mRNA Diagnostic and Prognostic Biomarkers of Acute Ischemic Stroke From Peripheral Blood Leukocytes

BACKGROUND

Long noncoding RNA (lncRNA) and mRNA profiles in leukocytes have shown potential as biomarkers for acute ischemic stroke (AIS). This study aimed to identify altered lncRNA and target mRNA profiles in peripheral blood leukocytes as biomarkers and to assess the diagnostic value and association with AIS prognosis.

METHODS AND RESULTS

Differentially expressed lncRNAs (DElncRNAs) and differentially expressed target mRNAs (DEmRNAs) were screened by RNA sequencing in the discovery set, which consisted of 10 patients with AIS and 20 controls. Validation sets consisted of a multicenter (311 AIS versus 303 controls) and a nested case-control study (351 AIS versus 352 controls). The discriminative value of DElncRNAs and DEmRNAs added to the traditional risk factors was estimated with the area under the curve. NAMPT-AS, FARP1-AS1, FTH1, and NAMPT were identified in the multicenter case-control study (P<0.05). LncRNA NAMPT-AS was associated with cis-target mRNA NAMPT and trans-target mRNA FTH1 in all validation sets (P<0.001). Similarly, AIS cases exhibited upregulated lncRNA FARP-AS1 and FTH1 expression (P<0.001) in the nested case-control study (P<0.001). Furthermore, lncRNA FARP1-AS1 expression was upregulated in AIS patients at discharge with an unfavorable outcome (P<0.001). Positive correlations were found between NAMPT expression level and NIHSS scores of AIS patients (P<0.05). Adding 2 lncRNAs and 2 target mRNAs to the traditional risk factor model improved area under the curve by 22.8% and 5.2% in the multicenter and the nested case-control studies, respectively.

CONCLUSIONS

lncRNA NAMPT-AS and FARP1-AS1 have potential as diagnostic biomarkers for AIS and exhibit good performance when combined with target mRNA NAMPT and FTH1.

Electroacupuncture Promotes Nerve Regeneration and Functional Recovery Through Regulating lncRNA GAS5 Targeting miR-21 After Sciatic Nerve Injury

Although the benefits of electroacupuncture (EA) for peripheral nerve injury (PNI) are well accepted in clinical practice, the underlying mechanism remains incompletely elucidated. In our study, we observed that EA intervention led to a reduction in the expression of the long non-coding RNA growth-arrest-specific transcript 5 (GAS5) and an increased in miR-21 levels within the injured nerve, effectively promoting functional recovery and nerve regeneration following sciatic nerve injury (SNI). In contrast, administration of adeno-associated virus expressing GAS5 (AAV-GAS5) weakened the therapeutic effect of EA. On the other hand, both silencing GAS5 and introducing a miR-21 mimic prominently enhanced the proliferation activity and migration ability of Schwann cells (SCs), while also inhibiting SCs apoptosis. On the contrary, inhibition of SCs apoptosis was found to be mediated by miR-21. Additionally, overexpression of GAS5 counteracted the effects of the miR-21 mimic on SCs. Moreover, SCs that transfected with the miR-21 mimic promoted neurite growth in hypoxia/reoxygenation-induced neurons, which might be prevented by overexpressing GAS5. Furthermore, GAS5 was found to be widely distributed in the cytoplasm and was negatively regulated by miR-21. Consequently, the targeting of GAS5 by miR-21 represents a potential mechanism through which EA enhances reinnervation and functional restoration following SNI. Mechanistically, the GAS5/miR-21 axis can modulate the proliferation, migration, and apoptosis of SCs while potentially influencing the neurite growth of neurons.

Non-Coding RNA in Microglia Activation and Neuroinflammation in Alzheimer's Disease

Alzheimer's disease (AD) is a neurodegenerative disorder characterized by complex pathophysiological features. Amyloid plaques resulting from extracellular amyloid deposition and neurofibrillary tangles formed by intracellular hyperphosphorylated tau accumulation serve as primary neuropathological criteria for AD diagnosis. The activation of microglia has been closely associated with these pathological manifestations. Non-coding RNA (ncRNA), a versatile molecule involved in various cellular functions such as genetic information storage and transport, as well as catalysis of biochemical reactions, plays a crucial role in microglial activation. This review aims to investigate the regulatory role of ncRNAs in protein expression by directly targeting genes, proteins, and interactions. Furthermore, it explores the ability of ncRNAs to modulate inflammatory pathways, influence the expression of inflammatory factors, and regulate microglia activation, all of which contribute to neuroinflammation and AD. However, there are still significant controversies surrounding microglial activation and polarization. The categorization into M1 and M2 phenotypes may oversimplify the intricate and multifaceted regulatory processes in microglial response to neuroinflammation. Limited research has been conducted on the role of ncRNAs in regulating microglial activation and inducing distinct polarization states in the context of neuroinflammation. Moreover, the regulatory mechanisms through which ncRNAs govern microglial function continue to be refined. The current understanding of ncRNA regulatory pathways involved in microglial activation remains incomplete and may be influenced by spatial, temporal, and tissue-specific factors. Therefore, further in-depth investigations are warranted. In conclusion, there are ongoing debates and uncertainties regarding the activation and polarization of microglial cells, particularly concerning the categorization into M1 and M2 phenotypes. The study of ncRNA regulation in microglial activation and polarization, as well as its mechanisms, is still in its early stages and requires further investigation. However, this review offers new insights and opportunities for therapeutic approaches in AD. The development of ncRNA-based drugs may hold promise as a new direction in AD treatment.