LncRNA SNHG15 Promotes Oxidative Stress Damage to Regulate the Occurrence and Development of Cerebral Ischemia/Reperfusion Injury by Targeting the miR-141/SIRT1 Axis

Neuroprotective potential for mitigating ischemia-reperfusion-induced damage

Reperfusion following cerebral ischemia causes both structural and functional damage to brain tissue and could aggravate a patient's condition; this phenomenon is known as cerebral ischemia-reperfusion injury. Current studies have elucidated the neuroprotective role of the sirtuin protein family (Sirtuins) in modulating cerebral ischemia-reperfusion injury. However, the potential of utilizing it as a novel intervention target to influence the prognosis of cerebral ischemia-reperfusion injury requires additional exploration. In this review, the origin and research progress of Sirtuins are summarized, suggesting the involvement of Sirtuins in diverse mechanisms that affect cerebral ischemia-reperfusion injury, including inflammation, oxidative stress, blood-brain barrier damage, apoptosis, pyroptosis, and autophagy. The therapeutic avenues related to Sirtuins that may improve the prognosis of cerebral ischemia-reperfusion injury were also investigated by modulating Sirtuins expression and affecting representative pathways, such as nuclear factor-kappa B signaling, oxidative stress mediated by adenosine monophosphate-activated protein kinase, and the forkhead box O. This review also summarizes the potential of endogenous substances, such as RNA and hormones, drugs, dietary supplements, and emerging therapies that regulate Sirtuins expression. This review also reveals that regulating Sirtuins mitigates cerebral ischemia-reperfusion injury when combined with other risk factors. While Sirtuins show promise as a potential target for the treatment of cerebral ischemia-reperfusion injury, most recent studies are based on rodent models with circadian rhythms that are distinct from those of humans, potentially influencing the efficacy of Sirtuins-targeting drug therapies. Overall, this review provides new insights into the role of Sirtuins in the pathology and treatment of cerebral ischemia-reperfusion injury.

Cerebral ischemia-induced gene expression changes in diabetic mice from acute to subacute stage

Diabetes is a risk factor for stroke; however, its impact on stroke progression at the genomic level is not well understood. To address this gap, we used transcriptome sequencing to explore the relationship between lncRNA and mRNA expression patterns and the reperfusion duration in the cortex of diabetically induced stroke mice. First, focal ischemia was induced in adult male ob/ob mice, which were then subjected to reperfusion periods of one, three, or seven days. Total RNA was extracted from the ischemic cortical tissue for RNA sequencing, and the resulting reads were aligned to the GRCm38 murine reference genome. A total of 672 mRNAs and 301 lncRNAs were identified as differentially expressed one day post-stroke, 1195 mRNAs and 66 lncRNAs at three days post-stroke, and 1069 mRNAs and 75 lncRNAs at seven days post-stroke. Stage-specific differentially expressed mRNAs were bioinformatically analyzed and found significantly enriched in processes such as apoptosis, angiogenesis, and lipid metabolism at one, three, and seven days post-stroke, respectively. Stage-specific DElncRNA-mRNA cis-regulatory relationships were constructed using these biological processes as examples, revealing the potential roles of four pairs of lncRNA-mRNAs (Gm39787-Lcn2, Gm46111-Drd2, D3300500i16Rik-Fosl1, and Gm41689-Egr1) in apoptosis. Additionally, Gm40237-Tie1 and Gm52352-Pdgfrb are associated with angiogenesis and lipid metabolism, respectively. In conclusion, our study demonstrated that lncRNA and mRNA expression in the cortex of transient focal ischemia-induced diabetic mice undergo extensive alterations, providing insights into complex molecular interactions underlying diabetic stroke.

Sirtuins: Promising Therapeutic Targets to Treat Ischemic Stroke

Stroke is a major cause of mortality and disability globally, with ischemic stroke (IS) accounting for over 80% of all stroke cases. The pathological process of IS involves numerous signal molecules, among which are the highly conserved nicotinamide adenine dinucleotide (NAD+)-dependent enzymes known as sirtuins (SIRTs). SIRTs modulate various biological processes, including cell differentiation, energy metabolism, DNA repair, inflammation, and oxidative stress. Importantly, several studies have reported a correlation between SIRTs and IS. This review introduces the general aspects of SIRTs, including their distribution, subcellular location, enzyme activity, and substrate. We also discuss their regulatory roles and potential mechanisms in IS. Finally, we describe the current therapeutic methods based on SIRTs, such as pharmacotherapy, non-pharmacological therapeutic/rehabilitative interventions, epigenetic regulators, potential molecules, and stem cell-derived exosome therapy. The data collected in this study will potentially contribute to both clinical and fundamental research on SIRTs, geared towards developing effective therapeutic candidates for future treatment of IS.

Interaction between SIRT1 and non-coding RNAs in different disorders

SIRT1 is a member of the sirtuin family functioning in the process of removal of acetyl groups from different proteins. This protein has several biological functions and is involved in the pathogenesis of metabolic diseases, malignancy, aging, neurodegenerative disorders and inflammation. Several long non-coding RNAs (lncRNAs), microRNAs (miRNAs) and circular RNAs (circRNAs) have been found to interact with SIRT1. These interactions have been assessed in the contexts of sepsis, cardiomyopathy, heart failure, non-alcoholic fatty liver disease, chronic hepatitis, cardiac fibrosis, myocardial ischemia/reperfusion injury, diabetes, ischemic stroke, immune-related disorders and cancers. Notably, SIRT1-interacting non-coding RNAs have been found to interact with each other. Several circRNA/miRNA and lncRNA/miRNA pairs that interact with SIRT1 have been identified. These axes are potential targets for design of novel therapies for different disorders. In the current review, we summarize the interactions between three classes of non-coding RNAs and SIRT1.

Ursolic acid ameliorates traumatic brain injury in mice by regulating microRNA-141-mediated PDCD4/PI3K/AKT signaling pathway

BACKGROUND

Neuronal apoptosis and inflammation are the key pathogenic features of secondary brain injury, which results in the neurological impairment that traumatic brain injury (TBI) patients experience. Ursolic Acid (UA) has been shown to have neuroprotective properties against brain damage, however, detailed mechanisms have not been fully disclosed. Research on brain-related microRNAs (miRNAs) has opened up new possibilities for the neuroprotective treatment of UA by manipulating miRNAs. The present study was designed to investigate the impact of UA on neuronal apoptosis and the inflammatory response in TBI mice.

METHODS

The mice's neurologic condition was assessed using the modified neurological severity score (mNSS) and the learning and memory abilities were assessed using the Morris water maze (MWM). Cell apoptosis, oxidative stress, and inflammation were utilized to examine the impact of UA on neuronal pathological damage. miR-141-3p was selected to evaluate whether UA influences miRNAs in a way that has neuroprotective benefits.

RESULTS

The results showed that UA markedly decreased brain edema and neuronal mortality through oxidative stress and neuroinflammation in TBI mice. Using data from the GEO database, we found that miR-141-3p was considerably downregulated in TBI mice and that this downregulation was reversed by UA treatment. Further studies have shown that UA regulates miR-141-3p expression to exhibit its neuroprotective effect in mouse models and cell injury models. Then, miR-141-3p was discovered to directly target PDCD4 in TBI mice and neurons, a well-known PI3K/AKT pathway regulator in the neurons. Most importantly, the upregulation of phosphorylated (p)-AKT and p-PI3K provided the most compelling evidence that UA reactivated the PI3K/AKT pathway in the TBI mouse model, which was through regulating miR-141-3p.

CONCLUSION

Our findings support the notion that UA can improve TBI by modulating miR-141 mediated PDCD4/PI3K/AKT signaling pathway.

The role of lncRNAs/miRNAs/Sirt1 axis in myocardial and cerebral injury

In recent years, researchers have begun to realize the importance of the role of non-coding RNAs in the treatment of cancer and cardiovascular and neurological diseases. LncRNAs and miRNAs are important non-coding RNAs, which regulate gene expression and activate mRNA translation through binding to diverse target sites. Their involvement in the regulation of protein function and the modulation of physiological and pathological conditions continues to be investigated. Sirtuins, especially Sirt1, have a critical function in regulating a variety of physiological processes such as oxidative stress, inflammation, apoptosis, and autophagy. The lncRNAs/miRNAs/Sirt1 axis may be a novel regulatory mechanism, which is involved in the progression and/or prevention of numerous diseases. This review focuses on recent findings on the crosstalk between non-coding RNAs and Sirt1 in myocardial and cerebral injuries and may provide some insight into the development of novel approaches in the treatment of these disorders.Abbreviation: BMECs, brain microvascular endothelial cells; C2dat1, calcium/calmodulin-dependent protein kinase type II subunit delta (CAMK2D)-associated transcript 1; EPCs, endothelial progenitor cells; FOXOs, forkhead transcription factors; GAS5, growth arrest-specific 5; HAECs, human aortic endothelial cells; HAND2-AS1, HAND2 Antisense RNA 1; HIF-1α, hypoxia-inducible factor-1α; ILF3-AS1, interleukin enhancer-binding factor 3-antisense RNA 1; KLF3-AS1, KLF3 antisense RNA 1; LncRNA, long noncoding RNA; LUADT1, Lung Adenocarcinoma Associated Transcript 1; MALAT1, Metastasis-associated lung adenocarcinoma transcript 1; miRNA, microRNA; NEAT1, nuclear enriched abundant transcript 1; NF-κB, nuclear factor kappa B; OIP5-AS1, Opa-interacting protein 5-antisense transcript 1; Sirt1-AS, Sirt1 Antisense RNA; SNHG7, small nucleolar RNA host gene 7; SNHG8, small nucleolar RNA host gene 8; SNHG12, small nucleolar RNA host gene 12; SNHG15, small nucleolar RNA host gene 15; STAT3, signal transducers and activators of transcription 3; TUG1, taurine up-regulated gene 1; VSMCs, vascular smooth muscle cells; XIST, X inactive specific transcript; ZFAS1, ZNFX1 Antisense RNA 1.

Pathophysiology of Ischemic Stroke: Noncoding RNA Role in Oxidative Stress

Stroke is a neurological disease that causes significant disability and death worldwide. Ischemic stroke accounts for 75% of all strokes. The pathophysiological processes underlying ischemic stroke include oxidative stress, the toxicity of excitatory amino acids, ion disorder, enhanced apoptosis, and inflammation. Noncoding RNAs (ncRNAs) may have a vital role in regulating the pathophysiological processes of ischemic stroke, as confirmed by the altered expression of ncRNAs in blood samples from acute ischemic stroke patients, animal models, and oxygen-glucose-deprived (OGD) cell models. Due to specific changes in expression, ncRNAs can potentially be biomarkers for the diagnosis, treatment, and prognosis of ischemic stroke. As an important brain cell component, glial cells mediate the occurrence and progression of oxidative stress after ischemic stroke, and ncRNAs are an irreplaceable part of this mechanism. This review highlights the impact of ncRNAs in the oxidative stress process of ischemic stroke. It focuses on specific ncRNAs that underlie the pathophysiology of ischemic stroke and have potential as diagnostic biomarkers and therapeutic targets.

Inhibition of circular RNA circ_0138959 alleviates pyroptosis of human gingival fibroblasts via the microRNA-527/caspase-5 axis

Circular RNA (circRNA) plays a regulatory role in periodontitis. This study explored whether circ_0138959 affected lipopolysaccharide (LPS)-induced pyroptosis in human gingival fibroblasts (HGFs). The periodontal ligament (PDL) tissues and HGFs were derived from patients with periodontitis and healthy volunteers. HGFs treated with LPS were considered to mimic periodontitis in vitro. Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to evaluate the mRNA expression levels of circRNAs, miR-527, and caspase-5 (CASP5), and Western blotting assay was used to measure protein expression levels of caspase-1, caspase-4, and cleaved N-terminal gasdermin D (GSDMD-N). Cell viability was evaluated by cell counting kit-8 (CCK-8) assay. The concentration of lactate dehydrogenase (LDH), interleukin (IL)-1β, and IL-18 and the pyroptosis rate were determined to evaluate pyroptosis. The interaction between miR-527 and circ_0138959 or CASP5 was verified by dual-luciferase reporter and RNA pull-down assays. Circ_0138959 expression was higher in the PDL tissues of patients with periodontitis than in the healthy group; likewise, circ_0138959 was also upregulated in LPS-treated HGFs. Suppressed circ_0138959 increased cell viability and decreased pyroptosis of HGFs induced by LPS. miR-527 was a target of circ_0138959, and inhibition of miR-527 contributed to the dysfunction of LPS-treated HGFs and reversed the protective effects of downregulated circ_0138959. Additionally, miR-527 targeted CASP5. Increased CASP5 abrogated the effects of overexpressed miR-527 on cell viability and pyroptosis of LPS-treated HGFs. Inhibition of circ_0138959 promoted cell viability and suppressed pyroptosis of HGFs via the miR-527/CASP5 axis. Therefore, knockdown of circ_0138959 may be a promising therapy for periodontitis.