MicroRNA-579-3p Exerts Neuroprotective Effects Against Ischemic Stroke via Anti-Inflammation and Anti-Apoptosis

Involvement of circ_0029407 in Caerulein-Evoked Cytotoxicity in Human Pancreatic Cells via the miR-579-3p/TLR4/NF-κB Pathway

Acute pancreatitis (AP) is the most prevalent gastrointestinal inflammatory disease. Circular RNAs (circRNAs) are implicated in the development of AP. Here, we identified the precise action of circ_0029407 in AP development. Human pancreatic epithelial cells (HPECs) were stimulated with caerulein. Cell viability, proliferation, and apoptosis were gauged by Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), and flow cytometry assays, respectively. Circ_0029407, microRNA (miR)-579-3p, and toll-like receptor 4 (TLR4) were quantified by a qRT-PCR or western blot assay. Dual-luciferase reporter and RNA pull-down assays were performed to evaluate the direct relationship between miR-579-3p and circ_0029407 or TLR4. Our results indicated that circ_0029407 was markedly overexpressed in AP serum samples and caerulein-stimulated HPECs. Reduction of circ_0029407 attenuated caerulein-imposed HPEC damage by promoting cell proliferation and repressing cell apoptosis and inflammation. Mechanistically, circ_0029407 contained a miR-579-3p binding site, and miR-579-3p downregulation reversed the effect of circ_0029407 reduction on caerulein-imposed HPEC damage. TLR4 was identified as a direct and functional target of miR-579-3p, and TLR4 overexpression reversed the impact of miR-579-3p upregulation on attenuating caerulein-imposed HPEC damage. Moreover, circ_0029407 regulated the TLR4/nuclear factor NF-kappaB (NF-κB) signaling by acting as a competing endogenous RNA (ceRNA) for miR-579-3p. Our study suggests that circ_0029407 regulates caerulein-imposed cell injury in human pancreatic cells at least in part via the TLR4/NF-κB signaling pathway by functioning as a ceRNA for miR-579-3p.

Brain microvascular endothelial cell-derived exosomes transmitting circ_0000495 promote microglial M1-polarization and endothelial cell injury under hypoxia condition

Human brain microvascular endothelial cells (HBMVECs) and microglia play critical roles in regulating cerebral homeostasis during ischemic stroke. However, the role of HBMVECs-derived exosomes in microglia polarization after stroke remains unknown. We isolated exosomes (Exos) from oxygen glucose deprivation (OGD)-exposed HBMVECs, before added them into microglia. Microglia polarization markers were tested using RT-qPCR or flow cytometry. Inflammatory cytokines were measured with ELISA. Endothelial cell damage was assessed by cell viability, apoptosis, apoptosis-related proteins, oxidative stress, and angiogenic activity using CCK-8, flow cytometry, western blot, ELISA, and endothelial tube formation assay, respectively. We also established middle cerebral artery occlusion (MCAO) mice model to examine the function of circ_0000495 on stroke in vivo. Our study found that HBMVECs-Exos reduced M2 markers (IL-10, CD163, and CD206), increased M1 markers (TNF-α, IL-1β, and IL-12), CD86-positive cells, and inflammatory cytokines (TNF-α and IL-1β), indicating the promotion of microglial M1-polarization. Microglial M1-polarization induced by HBMVECs-Exos reduced viability and promoted apoptosis and oxidative stress, revealing the aggravation of endothelial cell damage. However, circ_0000495 silencing inhibited HBMVECs-Exos-induced alterations. Mechanistically, circ_0000495 adsorbed miR-579-3p to upregulate toll-like receptor 4 (TLR4) in microglia; miR-579-3p suppressed HBMVECs-Exos-induced alterations via declining TLR4; furthermore, Yin Yang 1 (YY1) transcriptionally activated circ_0000495 in HBMVECs. Importantly, circ_0000495 aggravated ischemic brain injury in vivo via activating TLR4/nuclear factor-κB (NF-κB) pathway. Collectively, OGD-treated HBMVECs-Exos transmitted circ_0000495 to regulate miR-579-3p/TLR4/NF-κB axis in microglia, thereby facilitating microglial M1-polarization and endothelial cell damage.

miR-26a Improves Microglial Activation and Neuronal Apoptosis in a Rat Model of Cerebral Infarction by Regulating the TREM1-TLR4/MyD88/NF-κB Axis

Emerging studies have indicated that abnormally expressed microRNAs (miRNAs) are related to the pathogenesis of cerebral ischemia. Nevertheless, the function of miR-26a in neuronal damage and microglial activation during cerebral infarction remains elusive. It was revealed that miR-26a was downregulated in oxygen-glucose deprivation (OGD)-treated microglia and neurons. Overexpressing miR-26a reduced the inflammatory reaction in BV2 cells and decreased neuronal apoptosis following OGD stimulation. miR-26a upregulation inactivated the TLR4/MyD88/NF-κB pathway and inhibited TREM1 expression. Repressing NF-κB phosphorylation inhibited the miR-26a level. As supported by the dual-luciferase reporter assay, TREM1 was directly targeted by miR-26a. Furthermore, a rat model of middle cerebral artery occlusion (MCAO) was built. We discovered that miR-26a improved cognitive, learning, and motor functions and reduced cerebral edema in MCAO rats. Mechanistically, upregulating miR-26a reduced inflammation and neuronal apoptosis by mitigating the TREM1-TLR4/MyD88/NF-κB pathway in the MCAO rat model. Collectively, this study verified that the miR-26a-TREM1-TLR4/MyD88/NF-κB axis contributes to modulating OGD-mediated microglial activation and neuronal injury.

Circ_0007706 downregulation ameliorates neonatal hypoxic ischemic encephalopathy via regulating the miR-579-3p/TRAF6 axis

BACKGROUND

Neonatal hypoxic ischemic encephalopathy (HIE) is a main factor of neonatal death and permanent neurologic deficit. This study sought to investigate the functional role of hsa_circ_0007706 (circ_0007706) in modulating neonatal HIE.

METHODS

In vitro HIE cell model was established in hBMVECs under the condition of oxygen‑glucose deprivation/reperfusion (OGD/R) treatment. qRT-PCR analysis was utilized for detecting the level of circ_0007706, microRNA-579-3p (miR-579-3p) and TNF receptor-associated factor 6 (TRAF6). RNase R treatment and Oligo (dT) ₁₈ primers were employed to verify the features of circ_0007706, and nucleocytoplasmic separation was conducted for determining the location of circ_0007706. CCK-8 assay, EdU assay, and flow cytometry were carried out to measure cell proliferation and apoptosis, respectively. The protein expression of Bax, Bcl-2 and TRAF6 was detected using western blot. Meanwhile, the levels of the pro-inflammatory factors were determined via ELISA. SOD activity and MDA level were assessed via the respective kits. Besides, dual-luciferase reporter assay and RNA pull-down were used to identify the association between miR-579-3p and circ_0007706 or TRAF6.

RESULTS

Circ_0007706 was elevated in HIE newborns and OGD/R cell model. Knockdown of circ_0007706 greatly alleviated OGD/R-induced injury, inflammatory response and oxidative stress. We found that miR-579-3p was a direct target of circ_0007706, and miR-579-3p inhibitor could reverse the impact of circ_0007706 knockdown on OGD/R-caused cell damage in hBMVECs. In addition, miR-579-3p directly interacted with TRAF6, and the protective effects of miR-579-3p on OGD/R-induced injury in hBMVECs were harbored by TRAF6 overexpression. Our data indicated that circ_0007706 knockdown could downregulate the expression of TRAF6 by sponging miR-579-3p in OGD/R-treated hBMVECs.

CONCLUSION

This study demonstrated that circ_0007706 knockdown assuaged HIE-induced injury by decreasing TRAF6 expression via targeting miR-579-3p.

Circ_0000011 promotes cerebral ischemia/reperfusion injury via miR-27a-3p-dependent regulation of NRIP1

BACKGROUND

Cerebral ischemia/reperfusion (I/R) can result in brain function impairments. Circular RNAs (circRNAs) have emerged as vital regulators in cerebral I/R injury. However, the functions of mmu_circ_0000011 in cerebral I/R injury are still unclear. Thus, in this study, we aimed to explore the effect of mmu_circ_0000011 on cerebral I/R injury.

METHODS

Oxygen-glucose deprivation and reperfusion (OGD/R)-induced HT-22 cells were used to mimic the condition of cerebral I/R injury in vitro. Cell Counting Kit-8 (CCK-8) assay, lactate dehydrogenase (LDH) assay, 5'-ethynyl-2'-deoxyuridine (EdU) assay and flow cytometry analysis were utilized to assess cell viability, LDH release, proliferation and apoptosis, respectively. qRT-PCR and western blot were performed to determined the levels of circ_0000011, miR-27a-3p and NRIP1. Dual-luciferase reporter assay and RNA pull-down assay were utilized to analyze the targeting relation of circ_0000011, miR-27a-3p and NRIP1.

RESULTS

OGD/R treatment inhibited HT-22 cell viability and promoted LDH release, cell apoptosis and inflammation. Circ_0000011 level was increased in OGD/R-induced HT-22 cells. Silencing of circ_0000011 promoted cell proliferation and inhibited LDH release, apoptosis and inflammation in OGD/R-treated HT-22 cells. For mechanism analysis, circ_0000011 was demonstrated to sponge miR-27a-3p, which directly targeted NRIP1. MiR-27a-3p inhibition or NRIP1 overexpression ameliorated the impacts of circ_0000011 silencing on cell proliferation, LDH release, apoptosis and inflammation in OGD/R-treated HT-22 cells.

CONCLUSIONS

Circ_0000011 promotes OGD/R-induced HT-22 cell impairments by elevating NRIP1 through sponging miR-27a-3p.

Characterization of extracellular vesicle miRNA identified in peripheral blood of chronic pancreatitis patients

Plasma-derived extracellular vesicles (EV) can serve as markers of cell damage/disease but can also have therapeutic utility depending on the nature of their cargo, such as miRNA. Currently, there are challenges and lack of innovations regarding early diagnosis and therapeutic options within different aspects of management of patients suffering from chronic pancreatitis (CP). Use of EV as biomarkers for pancreatic health and/or as adjuvant therapy would make a difference in management of these patients. The aim of this study was to characterize the miRNA cargo of EV purified from the plasma of CP patients and compared to those of healthy participants. EVs were isolated from plasma of 15 CP patients and 10 healthy controls. Nanoparticle tracking analysis was used to determine frequency and size, while NanoString technology was used to characterize the miRNA cargo. Relevant clinical parameters were correlated with EV miRNA cargo. ~ 30 miRNA species were identified to have significantly (p < 0.05) different expression in EV from individuals with CP compared to healthy individuals; ~ 40 miRNA were differentially expressed in EV from pre-diabetic versus non-diabetic CP patients. miR-579-3p, while exhibiting significantly lower (~ 16-fold) expression in CP compared to healthy and lower (~ 24-fold) in CP narcotic users compared to the non-users, is actually enriched (~ 32-fold) within EV in pre-diabetic CP patients compared to non-diabetic CP patients. A unique pattern was identified in female CP patients. These data support the prospect of using a plasma-derived EV cargo to assess pancreatic health and its therapeutic potential in CP patients.

Emerging Impact of Non-coding RNAs in the Pathology of Stroke

Ischemic stroke (IS) is an acute cerebral vascular event with high mortality and morbidity. Though the precise pathophysiologic routes leading to this condition are not entirely clarified, growing evidence from animal and human experiments has exhibited the impact of non-coding RNAs in the pathogenesis of IS. Various lncRNAs namely MALAT1, linc-SLC22A2, linc-OBP2B-1, linc_luo_1172, linc-DHFRL1-4, SNHG15, linc-FAM98A-3, H19, MEG3, ANRIL, MIAT, and GAS5 are possibly involved in the pathogenesis of IS. Meanwhile, lots of miRNAs contribute in this process. Differential expression of lncRNAs and miRNAs in the sera of IS patients versus unaffected individuals has endowed these transcripts the aptitude to distinguish at risk patients. Despite conduction of comprehensive assays for evaluation of the influence of lncRNAs/miRNAs in the pathogenesis of IS, therapeutic impacts of these transcripts in IS have not been clarified. In the present paper, we review the impact of lncRNAs/miRNAs in the pathobiology of IS through assessment of evidence provided by human and animal studies.

Circular RNA hsa_circ_0033144 (CircBCL11B) regulates oral squamous cell carcinoma progression via the miR-579/LASP1 axis

Oral squamous cell carcinoma is one of the most common malignant tumors of the head and neck. Increasing evidence suggests that various non-coding RNAs, such as circRNAs, are implicated in a myriad of biological processes supporting tumor progression. Recent studies have revealed that several circRNAs are dysregulated in oral squamous cell carcinoma (OSCC). However, their functional role in OSCC and the underlying mechanism remains to be further investigated. In this study, we aim to evaluate the biological role and survey the molecular mechanism of circBCL11B in regulating the progression of OSCC. We demonstrated that circBCL11B was significantly upregulated in OSCC tissues and cell lines, and the expression level was correlated with the malignancy. Silencing cirCBCL11B inhibited cell proliferation and migration, and also included cell apoptosis in OSCC cells. miR-145 was identified as a downstream target mediating the effect of circBCL11B by targeting LASP1. miR-145 negatively regulated LASP1 expression, which could be rescued by miR-145 inhibitor. Collectively, our study uncovered a functional role of circBCL11B/miR-579/LASP1 axis in OSCC, implying that targeting these molecules could be an intervention approach in OSCC treatment.

MiR-579-3p Protects Intestinal Mucosal Epithelial Cells from Hypoxia-Reoxygenation Injury by Targeting Cyclin-Dependent Kinase Inhibitor 1B

Intestinal ischemia/reperfusion (I/R) injury is a common tissue and organ injury during surgery. This study explores miR-579-3p’s effect on the hypoxia-reoxygenation injury of intestinal mucosal epithelial cells via cyclin-dependent kinase inhibitor 1B (CDKN1B). Fetal human cells (FHC) cells, which are human normal colorectal mucosal epithelial cells, were cultured in vitro to establish a hypoxia-reoxygenation (H/R) cell model. Nano-based qRT-PCR and Western blot detected miR-579-3p and CDKN1B expressions in HCCLM3 cells treated with H/R. CCK-8 method and flow cytometry measured miR-579-3p and CDKN1B expressions on cell activity and death after H/R treatment. Dual-Luciferase reporter experiment and Western blot analyzed the relationship between miR-579-3p and CDKN1B. After the FHC cells were treated with H/R, miR-579-3p expression was decreased, whereas CDKN1B expression was increased (P < 0.05). FHC cells’ activity was decreased, and its apoptosis rate was upregulated; also, TNF-α and IL-6 protein levels were significantly enhanced (P < 0.05). Nevertheless, the activity of FHC cells treated with H/R after miR-579-3p overexpression was significantly increased, while the apoptosis rate was upregulation, and TNF-α level, IL-6 levels were reduced (P < 0.05). The effect of inhibiting CDKN1B expression was the same as that of overexpression miR-579-3p. After CDKN1B overexpression, the H/R-treated FHC cells’ viability was reduced, while the apoptosis rate was elevated, and TNF-α and IL-6 levels were elevated (P < 0.05). Compared to miR-579-3p overexpression, FHC cell activity in treated with H/R after the overexpression of miR-579-3p+CDKN1B was reduced. At the same time, the apoptosis rate and the level of TNF-α and IL-6 protein were elevated (P < 0.05). In summary, MiR-579-3p’s targeting of CDKN1B protects FHC cells from H/R injury by alleviating H/R-induced apoptosis and inflammation.

Overexpression of circRNA circUCK2 Attenuates Cell Apoptosis in Cerebral Ischemia-Reperfusion Injury via miR-125b-5p/GDF11 Signaling

Circular RNAs (circRNAs) are expressed at high levels in the brain and are involved in various central nervous system diseases. However, the potential role of circRNAs in ischemic stroke-associated neuronal injury remains largely unknown. Herein, we uncovered the function and underlying mechanism of the circRNA UCK2 (circUCK2) in ischemia stroke. The oxygen-glucose deprivation model in HT-22 cells was used to mimic ischemia stroke in vitro. Neuronal viability and apoptosis were determined by Cell Counting Kit-8 (CCK-8) assays and TUNEL (terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate nick end labeling) staining, respectively. Middle cerebral artery occlusion was conducted to evaluate the function of circUCK2 in mice. The levels of circUCK2 were significantly decreased in brain tissues from a mouse model of focal cerebral ischemia and reperfusion. Upregulated circUCK2 levels significantly decreased infarct volumes, attenuated neuronal injury, and improved neurological deficits. circUCK2 reduced oxygen glucose deprivation (OGD)-induced cell apoptosis by regulating transforming growth factor β (TGF-β)/mothers against decapentaplegic homolog 3 (Smad3) signaling. Furthermore, circUCK2 functioned as an endogenous miR-125b-5p sponge to inhibit miR-125b-5p activity, resulting in an increase in growth differentiation factor 11 (GDF11) expression and a subsequent amelioration of neuronal injury. Consequently, these findings showed that the circUCK2/miR-125b-5p/GDF11 axis is an essential signaling pathway during ischemia stroke. Thus, the circRNA circUCK2 may serve as a potential target for novel treatment in patients with ischemic stroke.

Oxytocin Receptor Signaling in Vascular Function and Stroke

The oxytocin receptor (OXTR) is a G protein-coupled receptor with a diverse repertoire of intracellular signaling pathways, which are activated in response to binding oxytocin (OXT) and a similar nonapeptide, vasopressin. This review summarizes the cell and molecular biology of the OXTR and its downstream signaling cascades, particularly focusing on the vasoactive functions of OXTR signaling in humans and animal models, as well as the clinical applications of OXTR targeting cerebrovascular accidents.