LncRNA MIAT enhances cerebral ischaemia/reperfusion injury in rat model via interacting with EGLN2 and reduces its ubiquitin-mediated degradation

PHD1-3 oxygen sensors in vivo-lessons learned from gene deletions

Oxygen sensors enable cells to adapt to limited oxygen availability (hypoxia), affecting various cellular and tissue responses. Prolyl-4-hydroxylase domain 1-3 (PHD1-3; also called Egln1-3, HIF-P4H 1-3, HIF-PH 1-3) proteins belong to the Fe2+- and 2-oxoglutarate-dependent dioxygenase superfamily and utilise molecular oxygen (O2) alongside 2-oxoglutarate as co-substrate to hydroxylate two proline residues of α subunits of the dimeric hypoxia inducible factor (HIF) transcription factor. PHD1-3-mediated hydroxylation of HIF-α leads to its degradation and inactivation. Recently, various PHD inhibitors (PHI) have entered the clinics for treatment of renal anaemia. Pre-clinical analyses indicate that PHI treatment may also be beneficial in numerous other hypoxia-associated diseases. Nonetheless, the underlying molecular mechanisms of the observed protective effects of PHIs are only partly understood, currently hindering their translation into the clinics. Moreover, the PHI-mediated increase of Epo levels is not beneficial in all hypoxia-associated diseases and PHD-selective inhibition may be advantageous. Here, we summarise the current knowledge about the relevance and function of each of the three PHD isoforms in vivo, based on the deletion or RNA interference-mediated knockdown of each single corresponding gene in rodents. This information is crucial for our understanding of the physiological relevance and function of the PHDs as well as for elucidating their individual impact on hypoxia-associated diseases. Furthermore, this knowledge highlights which diseases may best be targeted by PHD isoform-selective inhibitors in case such pharmacologic substances become available.

Genetic association between long non-coding RNA MIAT polymorphism and ischemic stroke susceptibility in the Chinese population

OBJECTIVES

The genetic association of long non-coding RNAs (lncRNAs) polymorphism with ischemic stroke (IS) susceptibility is not fully understood. To explore whether lncRNA MIAT rs1894720 polymorphism can predict the susceptibility of IS in the Chinese Han population.

MATERIALS AND METHODS

200 IS cases and 200 healthy controls were enrolled. Serum MIAT levels were tested via qRT-PCR. Rs1894720 genotyping was accomplished through Sanger sequencing.

RESULTS

MIAT rs1894720 genotypes were differentially distributed in IS and control groups. Rs1894720 TT genotype was considered to be a protective factor for IS risk in dominant model (GT + TT vs GG: OR = 0.630, 95 % CI = 0.412-0.962, P = 0.032). Further stratification results showed that individuals carrying the rs1894720 G allele in people older than 65 years, men, smokers, or those with hypertension had a higher risk of IS. MIAT rs1894720 GG genotype was positively related to the susceptibility to IS of LAA subtype compared with the healthy controls. GG genotype carriers had high serum MIAT levels compared to those with GT and TT genotypes.

CONCLUSIONS

MIAT rs1894720 polymorphism was associated with the risk of IS in the Chinese Han population, especially for LAA subtype. Rs1894720 GG genotype carriers were at greater risk of developing IS.

MIAT LncRNA: A multifunctional key player in non-oncological pathological conditions

The discovery of non-coding RNAs (ncRNAs) has unveiled a wide range of transcripts that do not encode proteins but play key roles in several cellular and molecular processes. Long noncoding RNAs (lncRNAs) are specific class of ncRNAs that are longer than 200 nucleotides and have gained significant attention due to their diverse mechanisms of action and potential involvement in various pathological conditions. In the current review, the authors focus on the role of lncRNAs, specifically highlighting the Myocardial Infarction Associated Transcript (MIAT), in non-oncological context. MIAT is a nuclear lncRNA that has been directly linked to myocardial infarction and is reported to control post-transcriptional processes as a competitive endogenous RNA (ceRNA) molecule. It interacts with microRNAs (miRNAs), thereby limiting the translation and expression of their respective target messenger RNA (mRNA) and regulating protein expression. Yet, MIAT has been implicated in other numerous pathological conditions such as other cardiovascular diseases, autoimmune disease, neurodegenerative diseases, metabolic diseases, and many others. In this review, the authors emphasize that MIAT exhibits distinct expression patterns and functions across different pathological conditions and is emerging as potential diagnostic, prognostic, and therapeutic agent. Additionally, the authors highlight the regulatory role of MIAT and shed light on the involvement of lncRNAs and specifically MIAT in various non-oncological pathological conditions.

Crosstalk between ubiquitin ligases and ncRNAs drives cardiovascular disease progression

Cardiovascular diseases (CVDs) are multifactorial chronic diseases and have the highest rates of morbidity and mortality worldwide. The ubiquitin-proteasome system (UPS) plays a crucial role in posttranslational modification and quality control of proteins, maintaining intracellular homeostasis via degradation of misfolded, short-lived, or nonfunctional regulatory proteins. Noncoding RNAs (ncRNAs, such as microRNAs, long noncoding RNAs, circular RNAs and small interfering RNAs) serve as epigenetic factors and directly or indirectly participate in various physiological and pathological processes. NcRNAs that regulate ubiquitination or are regulated by the UPS are involved in the execution of target protein stability. The cross-linked relationship between the UPS, ncRNAs and CVDs has drawn researchers' attention. Herein, we provide an update on recent developments and perspectives on how the crosstalk of the UPS and ncRNAs affects the pathological mechanisms of CVDs, particularly myocardial ischemia/reperfusion injury, myocardial infarction, cardiomyopathy, heart failure, atherosclerosis, hypertension, and ischemic stroke. In addition, we further envision that RNA interference or ncRNA mimics or inhibitors targeting the UPS can potentially be used as therapeutic tools and strategies.

Targeted RNAseq Revealed the Gene Expression Signature of Ferroptosis-Related Processes Associated with Disease Severity in Patients with Multiple Sclerosis

Detrimental molecular processes in multiple sclerosis (MS) lead to the cellular accumulation of lipid peroxidation products and iron in the CNS, which represents the main driving force for ferroptosis. Ferroptosis is an iron-dependent form of regulated cell death, with proposed roles in neurodegeneration, oligodendrocyte loss and neuroinflammation in the pathogenesis of MS. Ferroptosis-related gene expression signature and molecular markers, which could reflect MS severity and progression, are currently understudied in humans. To tackle these challenges, we have applied a curated approach to create and experimentally analyze a comprehensive panel of ferroptosis-related genes covering a wide range of biological processes associated with ferroptosis. We performed the first ferroptosis-related targeted RNAseq on PBMCs from highly distinctive MS phenotype groups: mild relapsing-remitting (RR) (n = 24) and severe secondary progressive (SP) (n = 24), along with protein detection of GPX4 and products of lipid peroxidation (MDA and 4-HNE). Out of 138 genes, 26 were differentially expressed genes (DEGs), indicating changes in both pro- and anti-ferroptotic genes, representing a molecular signature associated with MS severity. The top three DEGs, as non-core ferroptosis genes, CDKN1A, MAP1B and EGLN2, were replicated by qPCR to validate findings in independent patient groups (16 RR and 16 SP MS). Co-expression and interactions of DEGs were presented as additional valuable assets for deeper understanding of molecular mechanisms and key targets related to MS severity. Our study integrates a wide genetic signature and biochemical markers related to ferroptosis in easily obtainable PBMCs of MS patients with clinical data and disease severity, thus providing novel molecular markers which can complement disease-related changes in the brain and undergo further research as potential therapeutic targets.

lncRNA-MIAT rs9625066 polymorphism could be a potential biomarker for ischemic stroke

BACKGROUND

Ischemic stroke (IS) is a common and serious neurological condition that is highly fatal but so far no early diagnostic markers are available. Myocardial infarction-associated transcript (MIAT) is a long non-coding RNA (lncRNA) that could lead to IS by inducing autophagy and apoptosis in neuronal cells. However, there has been no report on the link between susceptibility to IS and the single-nucleotide polymorphisms (SNPs) of MIAT. This study aimed to investigate the association between MIAT gene polymorphisms and IS risk.

METHODS

A total of 320 IS patients and 310 age-, sex- and race-matched controls were included in this study. Four polymorphisms (rs2157598, rs5761664, rs1894720, and rs9625066) were genotyped by using SNPscan technique.

RESULTS

Among the 4 polymorphisms of MIAT, only rs9625066 was associated with IS risk (CA vs. CC: adjusted OR = 0.55, 95% CI, 0.37-0.85, P = 0.006; AA vs. CC: adjusted OR = 0.39, 95% CI, 0.16-0.94, P = 0.036; (AA + CA vs. CC: adjusted OR = 0.53, 95% CI, 0.35-0.80, P = 0.002; A vs. C adjusted OR = 0.59, 95% CI, 0.42-0.82, P = 0.002). Haplotype analysis showed a 1.32-fold increase (95% CI, 1.05-1.67, P = 0.017) in IS risk for rs2157598-rs5761664-rs1894720-rs9625066 (A-C-G-C). Logistic regression analysis identified some independent impact factors for IS including rs9625066 AA/AC, TC, TG, HDL-C (P < 0.05).

CONCLUSION

The rs9625066 polymorphism of MIAT might be associated with IS susceptibility in Chinese population, in which AA/CA plays a protective role in IS, whereas the CC genotype increases the risk of developing IS, suggesting it might be a marker predictive of IS risk.

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.

Ginsenoside compound K reduces ischemia/reperfusion-induced neuronal apoptosis by inhibiting PTP1B-mediated IRS1 tyrosine dephosphorylation

Background

Ginsenoside compound K (CK) stimulated activation of the PI3K-Akt signaling is one of the major mechanisms in promoting cell survival after stroke. However, the underlying mediators remain poorly understood. This study aimed to explore the docking protein of ginsenoside CK mediating the neuroprotective effects.

Materials and methods

Molecular docking, surface plasmon resonance, and cellular thermal shift assay were performed to explore ginsenoside CK interacting proteins. Neuroscreen-1 cells and middle cerebral artery occlusion (MCAO) model in rats were utilized as in-vitro and in-vivo models.

Results

Ginsenoside CK interacted with recombinant human PTP1B protein and impaired its tyrosine phosphatase activity. Pathway and process enrichment analysis confirmed the involvement of PTP1B and its interacting proteins in PI3K-Akt signaling pathway. PTP1B overexpression reduced the tyrosine phosphorylation of insulin receptor substrate 1 (IRS1) after oxygen-glucose deprivation/reoxygenation (OGD/R) in neuroscreen-1 cells. These regulations were confirmed in the ipsilateral ischemic hemisphere of the rat brains after MCAO/R. Ginsenoside CK treatment reversed these alterations and attenuated neuronal apoptosis.

Conclusion

Ginsenoside CK binds to PTP1B with a high affinity and inhibits PTP1B-mediated IRS1 tyrosine dephosphorylation. This novel mechanism helps explain the role of ginsenoside CK in activating the neuronal protective PI3K-Akt signaling pathway after ischemia-reperfusion injury.

Stigmasterol protects human brain microvessel endothelial cells against ischemia-reperfusion injury through suppressing EPHA2 phosphorylation

Stigmasterol is a plant sterol with anti-apoptotic, anti-oxidative and anti-inflammatory effect through multiple mechanisms. In this study, we further assessed whether it exerts protective effect on human brain microvessel endothelial cells (HBMECs) against ischemia-reperfusion injury and explored the underlying mechanisms. HBMECs were used to establish an in vitro oxygen and glucose deprivation/reperfusion (OGD/R) model, while a middle cerebral artery occlusion (MCAO) model of rats were constructed. The interaction between stigmasterol and EPHA2 was detected by surface plasmon resonance (SPR) and cellular thermal shift assay (CETSA). The results showed that 10 μmol·L^-1 stigmasterol significantly protected cell viability, alleviated the loss of tight junction proteins and attenuated the blood-brain barrier (BBB) damage induced by OGD/R in thein vitro model. Subsequent molecular docking showed that stigmasterol might interact with EPHA2 at multiple sites, including T692, a critical gatekeep residue of this receptor. Exogenous ephrin-A1 (an EPHA2 ligand) exacerbated OGD/R-induced EPHA2 phosphorylation at S897, facilitated ZO-1/claudin-5 loss, and promoted BBB leakage in vitro, which were significantly attenuated after stigmasterol treatment. The rat MCAO model confirmed these protective effects in vivo. In summary, these findings suggest that stigmasterol protects HBMECs against ischemia-reperfusion injury by maintaining cell viability, reducing the loss of tight junction proteins, and attenuating the BBB damage. These protective effects are at least meditated by its interaction with EPHA2 and inhibitory effect on EPHA2 phosphorylation.

Modulation of miR-205/ EGLN2 by rosuvastatin mitigates colistin-induced nephrotoxicity in rats: Involvement of ATF4/ CHOP and Nrf2 pathways

Although the beneficial role of microRNA has been investigated thoroughly, the reno-protective role of microRNA-205 (miR-205) against colistin-induced nephrotoxicity has not yet been tackled. Hence, our study sought to study the possible modulatory effect of rosuvastatin on miR-205 and its downstream target, Egl-9 family hypoxia-inducible factor 2 (EGLN2) to combat oxidative and endoplasmic reticulum (ER) stresses as pivotal contributors to colistin-associated renal injury. Rats were randomly divided into four groups; normal, colistin (300 000 IU/Kg/day; i.p), colistin pretreated with rosuvastatin (10 mg/kg; p.o) and colistin pretreated with rosuvastatin (20 mg/kg; p.o) for 6 successive days. Pretreatment with rosuvastatin attenuated renal injury induced by colistin and enhanced kidney function with a marked reduction in renal injury markers, neutrophil gelatinase-associated lipocalin, and kidney injury molecule-1. Besides, rosuvastatin upregulated renal miR-205 expression and suppressed gene expression of EGLN2. In addition, it downregulated ER stress-related genes (activation transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP)) along with caspases 12 and 3. It also induced the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) as detected by immunohistochemical examination besides increased renal antioxidants, reduced glutathione, and superoxide dismutase. In conclusion, rosuvastatin triggered a series of protective mechanisms against colistin-induced nephrotoxicity through modulating miR-205 and EGLN2 expression. Rosuvastatin suppressed ATF4/ CHOP trajectory and activated the Nrf2 pathway to substantiate its antioxidant and anti-apoptotic capacities.

LncRNA Miat promotes neuropathic pain through miR-362-3p/BAMBI signaling axis

The treatment of neuropathic pain (NP) has become an important subject to be studied and solved urgently in clinical practice. The role of long noncoding RNAs (lncRNAs) in NP development is becoming clear. Therefore, this study aimed to investigate the role and mechanism of lncRNA Miat in NP. In this study, chronic contractionary injury (CCI) mouse NP model was performed. Firstly, the effects of Miat on pain behavior in mice and the expression levels of pro-inflammatory cytokines and pro-inflammatory proteins in spinal cord tissue were explored by interfering with the expression of Miat. Then, Miat-targeted signaling pathway was predicted by bioinformatics and verified by dual luciferase reporter gene and RNA pull down. Finally, the mechanism of Miat was confirmed by the rescue experiments. Our results demonstrated that Miat knockdown alleviated paw withdrawal threshold, paw withdrawal latency, cold hyperalgesia frequency and neuroinflammation in CCI mice. MiR-362-3p was able to bind to Miat and BAMBI. Overall, Miat upregulated BAMBI by inhibiting miR-362-3p, thereby promoting the occurrence and development of NP. This study analyzed the possibility and effectiveness of targeting Miat for NP clinical treatment, in order to provide new ideas and technical methods for NP gene therapy.

Study on Circulating lncRNA Expression Profile in Patients with Cerebral Infarction

To analyze the difference of circulating lncRNA expression profile between the healthy control group and cerebral infarction (CI) patients and to study the epigenetic pathogenesis of CI. Forty patients with acute CI admitted to our hospital from December 2016 to December 2017 were selected as CI group, and 40 healthy people in physical examination center were selected as healthy group. In the CI group, blood samples were taken 5 mL at fasting in the morning (within 72 hours of CI), and the blood samples from healthy group were also taken 5 mL at fasting in the morning. The circulating lncRNA expression profile of serum sample was determined by high-throughput technique, and its difference was analyzed. Bioinformatics technology was used to explore its functional mechanism, and GO, KEGG analysis, and gene expression network were established for lncRNA with significant differences. Next, lnc-ZNF32-1 : 1 and lnc-PCGF5-2 : 1 were selected for further validation of serum lncRNA expression in ACI and NC groups, and ceRNA interaction network analysis, diagnostic specificity, and sensitivity of lnc-ZNF32-1 : 1 and lnc-PCGF5-2 : 1 were conducted. The results showed that compared with the healthy group, there were 512 known lncRNA expressed differentially in the serum of patients with CI, of which 371 were upregulated and 141 were downregulated, and 421 known mRNA expressed differentially, of which 245 were upregulated and 176 downregulated. The differentially expressed mRNA was mainly enriched in 53 gene functions, and the target gene was enriched in the pathways such as HTLV-I infection and pathways in cancer. In addition, the results explored that lnc-ZNF32-1 : 1 and lnc-PCGF5-2 : 1 have potential value for CI diagnosis. In conclusion, the expression profile of lncRNA in CI group was significantly different from that in healthy group, indicating that lncRNA might be closely related to the occurrence, development, and prognosis of CI.

Ginsenoside Rd protects cerebral endothelial cells from oxygen-glucose deprivation/reoxygenation induced pyroptosis via inhibiting SLC5A1 mediated sodium influx

Background

Ginsenoside Rd is a natural compound with promising neuroprotective effects. However, the underlying mechanisms are still not well-understood. In this study, we explored whether ginsenoside Rd exerts protective effects on cerebral endothelial cells after oxygen-glucose deprivation/reoxygenation (OGD/R) treatment and its potential docking proteins related to the underlying regulations.

Method

Commercially available primary human brain microvessel endothelial cells (HBMECs) were used for in vitro OGD/R studies. Cell viability, pyroptosis-associated protein expression and tight junction protein degradation were evaluated. Molecular docking proteins were predicted. Subsequent surface plasmon resonance (SPR) technology was utilized for validation. Flow cytometry was performed to quantify caspase-1 positive and PI positive (caspase-1+/PI+) pyroptotic cells.

Results

Ginsenoside Rd treatment attenuated OGD/R-induced damage of blood-brain barrier (BBB) integrity in vitro. It suppressed NLRP3 inflammasome activation (increased expression of NLRP3, cleaved caspase-1, IL-1β and GSDMD-N terminal (NT)) and subsequent cellular pyroptosis (caspase-1+/PI + cells). Ginsenoside Rd interacted with SLC5A1 with a high affinity and reduced OGD/R-induced sodium influx and potassium efflux in HBMECs. Inhibiting SLC5A1 using phlorizin suppressed OGD/R-activated NLRP3 inflammasome and pyroptosis in HBMECs.

Conclusion

Ginsenoside Rd protects HBMECs from OGD/R-induced injury partially via binding to SLC5A1, reducing OGD/R-induced sodium influx and potassium efflux, thereby alleviating NLRP3 inflammasome activation and pyroptosis.

LncRNA MIAT enhances cerebral ischaemia/reperfusion injury in rat model via interacting with EGLN2 and reduces its ubiquitin-mediated degradation

Long non-coding RNA (lncRNA) MIAT (myocardial infarction associated transcript) has been characterized as a functional lncRNA modulating cerebral ischaemic/reperfusion (I/R) injury. However, the underlying mechanisms remain poorly understood. This study explored the functional partners of MIAT in primary rat neurons and their regulation on I/R injury. Sprague-Dawley rats were used to construct middle cerebral artery occlusion (MCAO) models. Their cerebral cortical neurons were used for in vitro oxygen-glucose deprivation/reoxygenation (OGD/R) models. Results showed that MIAT interacted with EGLN2 in rat cortical neurons. MIAT overexpression or knockdown did not alter EGLN2 transcription. In contrast, MIAT overexpression increased EGLN2 stability after I/R injury via reducing its ubiquitin-mediated degradation. EGLN2 was a substrate of MDM2, a ubiquitin E3 ligase. MDM2 interacted with the N-terminal of EGLN2 and mediated its K48-linked poly-ubiquitination, thereby facilitating its proteasomal degradation. MIAT knockdown enhanced the interaction and reduced EGLN2 stability. MIAT overexpression enhanced infarct volume and induced a higher ratio of neuronal apoptosis. EGLN2 knockdown significantly reversed the injury. MIAT overexpression reduced oxidative pentose phosphate pathway flux and increased oxidized/reduced glutathione ratio, the effects of which were abrogated by EGLN2 knockdown. In conclusion, MIAT might act as a stabilizer of EGLN2 via reducing MDM2 mediated K48 poly-ubiquitination. MIAT-EGLN2 axis exacerbates I/R injury via altering redox homeostasis in neurons.