Initial research on the relationship between let-7 family members in the serum and massive cerebral infarction

Cell-Free Nucleic Acids for Early Diagnosis of Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

Rapid identification of acute ischemic stroke (AIS) is challenging in both pre-hospital and hospital settings. We aimed to identify the most promising cell-free nucleic acids (cfNAs) as diagnostic biomarkers for IS within 72 h from symptom onset. We searched PubMed, Web of Science, EMBASE, and Cochrane Library for published articles that evaluated blood cfNAs in the early diagnosis of AIS until 10 May 2023. The diagnostic performances of individual cfNAs were pooled by random-effects meta-analysis based on the fold change of biomarkers' level between AIS and non-AIS patients. Of 2955 records, 66 articles reporting 143 different cfNAs met the inclusion criteria. The median sample size was 110, and 21.4% of the studies performed validation. Among selected high-quality studies, miR-106b-5p, miR-124, miR-155, lncRNA H19, and cfDNA showed good diagnostic performance. Data from four studies on cfDNA involving 355 AIS patients and 97 controls were pooled in the meta-analysis, which showed a significant fold change between AIS and controls (pooled ratio 1.48, 95% confidence interval 1.23-1.79, p < 0.001). This review highlights that cfDNA, miR-106b-5p, miR-124, miR-155, and lncRNA H19 are the most promising biomarkers for AIS diagnosis, and further research is needed for verification.

Zhilong Huoxue Tongyu Capsule regulates the macrophage polarization and inflammatory response via the let-7i/TLR9/MyD88 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Zhilong Huoxue Tongyu Capsule (ZL) is clinically prescribed for acute ischemic stroke (AIS). However, only a few studies have addressed the mechanisms of ZL in treating AIS.

AIM OF THE STUDY

To explore the underlying mechanism of macrophage polarization and inflammation mediated by ZL, and to provide a reference for AIS treatment.

MATERIALS AND METHODS

Sixteen SD rats were fed with different dose of ZL (0, 0.4, 0.8, and 1.6 g/kg/d) for 4 days to prepare ZL serum. After 500 ng/mL lipopolysaccharide (LPS) stimulation, RAW264.7 cells were administrated with ZL serum. Then, experiments including ELISA, flow cytometry, real-time quantitative PCR and Western blot were performed to verify the effects of ZL on macrophage polarization and inflammation. Next, let-7i inhibitor was transfected in RAW264.7 cells when treated with LPS and ZL serum to verify the regulation of ZL on the let-7i/TLR9/MyD88 signaling pathway. Moreover, the interaction between let-7i and TLR9 was confirmed by the dual-luciferase assay.

RESULTS

ZL serum significantly decreased the expression of interleukin (IL)-6 and tumor necrosis factor-α (TNF-α), and increased the expression of IL-10 and transforming growth factor β1 (TGF-β1) of LPS stimulated-macrophages. Furthermore, ZL serum polarized macrophages toward M2, decreased the expressions of TLR9, MyD88, and iNOS, as well as increased the expressions of let-7i, CHIL3, and Arginase-1. It is worth mentioning that the effect of ZL serum is dose-dependent. However, let-7i inhibitor restored all the above effects in LPS stimulated-macrophages. In addition, TLR9 was the target of let-7i.

CONCLUSIONS

ZL targeted let-7i to inhibit TLR9 expression, thereby inhibiting the activation of the TLR9/MyD88 pathway, promoting the M2 polarization, and inhibiting the development of inflammation in AIS.

The miR-25802/KLF4/NF-κB signaling axis regulates microglia-mediated neuroinflammation in Alzheimer's disease

Microglia-mediated neuroinflammation plays a critical role in the occurrence and progression of Alzheimer's disease (AD). In recent years, studies have increasingly explored microRNAs as biomarkers and treatment interventions for AD. This study identified a novel microRNA termed miR-25802 from our high-throughput sequencing dataset of an AD model and explored its role and the underlying mechanism. The results confirmed the miRNA properties of miR-25802 based on bioinformatics and experimental verification. Expression of miR-25802 was increased in the plasma of AD patients and in the hippocampus of APP/PS1 and 5 × FAD mice carrying two and five familial AD gene mutations. Functional studies suggested that overexpression or inhibition of miR-25802 respectively aggravated or ameliorated AD-related pathology, including cognitive disability, Aβ deposition, microglial pro-inflammatory phenotype activation, and neuroinflammation, in 5 × FAD mice and homeostatic or LPS/IFN-γ-stimulated EOC20 microglia. Mechanistically, miR-25802 negatively regulates KLF4 by directly binding to KLF4 mRNA, thus stimulating microglia polarization toward the pro-inflammatory M1 phenotype by promoting the NF-κB-mediated inflammatory response. The results also showed that inhibition of miR-25802 increased microglial anti-inflammatory M2 phenotype activity and suppressed NF-κB-mediated inflammatory reactions in the brains of 5 × FAD mice, while overexpression of miR-25802 exacerbated microglial pro-inflammatory M1 activity by enhancing NF-κB pathways. Of note, AD-associated manifestations induced by inhibition or overexpression of miR-25802 via the NF-κB signaling pathway were reversed by KLF4 silencing or upregulation. Collectively, these results provide the first evidence that miR-25802 is a regulator of microglial activity and establish the role of miR-25802/KLF4/NF-κB signaling in microglia-mediated neuroinflammation, suggesting potential therapeutic targets for AD.

Zhilong Huoxue Tongyu Capsule attenuates hemorrhagic transformation through the let-7f/TLR4 signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Hemorrhagic transformation after acute ischemic stroke is a life-threatening disease that currently has no effective chemotherapy. Zhilong Huoxue Tongyu Capsule (ZL) is an empirical prescription of traditional Chinese medicine that is used to prevent and treat cardiovascular and cerebrovascular diseases in China. However, only a few studies have addressed the mechanisms of ZL in treating hemorrhagic transformation.

AIM OF THE STUDY

To evaluate the anti-inflammatory effects of ZL on hemorrhagic transformation model rats and lipopolysaccharide (LPS)-induced RAW264.7 macrophages and to explore the underlying molecular mechanisms.

MATERIALS AND METHODS

Murine RAW264.7 cells were treated with ZL and LPS (1 μg/mL), and cell viability was detected by cell counting kit-8 assay. RT-qPCR was used to detect the expression of inflammatory chemokines, microRNA let-7a/e/i/f, toll like receptor 4 (TLR4), myeloid differentiation factor 88 (MyD88), and nuclear factor kappa-B (NF-κB) p65. The protein expression levels of TLR4, MyD88, NF-κB p65, and apoptosis related molecules were determined by Western blotting. The apoptosis rate of RAW264.7 macrophages was detected by Annexin V-FITC/PI double staining. A hemorrhagic transformation model in rats was established by intraperitoneal injection of high glucose solution combined with thread embolization. Then, the model rats were observed behaviourally, pathologically, and molecularly. The gene expression of TLR4, MyD88, and NF-κB p65 was measured by RT-qPCR and used to evaluate the protective effect of ZL against hemorrhagic transformation in rats.

RESULTS

ZL (5, 20, 40 μg/mL) was beneficial in cell proliferation. LPS (1 μg/mL) stimulated the production of inflammatory chemokines and inhibited the production of let-7a/e/i/f, with let-7f being influenced most strongly. Moreover, overexpression of let-7f decreased the gene and protein levels of TLR4, MyD88, and NF-κB p65, downregulated TLR4, and inhibited its transcriptional activity. ZL (5, 20, and 40 μg·mL-1) inhibited the production of TLR4, MyD88, and NF-κB p65 and promoted the production of let-7f in a concentration-dependent manner. Furthermore, the blockade of TLR4 antagonized the promoting effects of TLR4 pathway activation in cell inflammation and apoptosis by downregulating let-7f. Critically, it was confirmed in vivo and in vitro that ZL upregulated the expression of let-7f and inhibited the gene expression of TLR4, MyD88, and NF-κB p65 to reduce inflammatory cell infiltration, which determined the occurrence of hemorrhagic transformation.

CONCLUSIONS

ZL can reduce inflammatory response by upregulating let-7f and subsequently inhibiting the TLR4 signaling pathway, thereby decreasing the occurrence of hemorrhagic transformation.

Genetic variants in the promoters of let-7 are associated with the risk and age at onset of ischemic stroke: A case control study

PURPOSE

Let-7 family members serve as crucial regulatory molecules in the pathogenesis of ischemic stroke. We predicted that genetic variations in the let-7 family's promoters may be linked to the risk of ischemic stroke. The connection of rs10877887 and rs13293512 in the let-7 family promoters with liability to ischemic stroke was explored in this study.

PATIENTS AND METHODS

Clinical data and peripheral blood samples were collected from 914 ischemic stroke patients and 836 controls in this case-control study. All statistical analyses were carried out using SPSS.

RESULTS

Our analysis results reveal that the rs10877887 TC+CC genotype in the dominant model is associated with a lower risk of ischemic stroke than the TT genotype. Individuals with heterozygous TC or homozygous CC genotypes in the male population showed higher odds of ischemic stroke than those with the wild TT genotype in rs13293512 analysis. Furthermore, there existed a multiplicative interaction between the rs10877887 C allele and the rs13293512 T allele. In the presence of the rs13293512 T allele, the effect of the rs10877887 C allele on ischemic stroke risk was increased. Similarly, in the presence of the rs10877887 C allele, the outcome of the rs13293512 T allele on ischemic stroke risk was elevated. In addition, the rs13293512 CC genotype seemed to lead to an earlier onset of ischemic stroke.

CONCLUSION

Our findings indicated that these two SNPs might have a joint role in IS and could potentially act as risk markers. Detecting let-7 promoter polymorphisms could raise awareness of the risk of IS, which directed individuals with risk alleles to have regular checks at an appropriate frequency to avoid developing the disease.

Male mice exposed to chronic intermittent ethanol exposure exhibit significant upregulation or downregulation of circular RNAs

B a ckground: Circular RNAs (circRNAs) have been crucially implicated in various diseases, however, their involvement in chronic intermittent ethanol (CIE) exposure remains unclear.O bjective: The present study was conducted to evaluate the circular RNA expression alteration in brain samples and to identify the molecular mechanisms underlying chronic intermittent ethanol exposure.M ethods: Male C57BL/6J mice (10 for each group) were given 4 weeks of chronic intermittent ethanol exposure. Whole brain samples were collected for high-throughput sequencing and circRNA bioinformatic analysis. Real-time quantitative PCR (RI-qPCR) and agarose electrophoresis were used to validate the differentially expressed circRNAs. Gene Ontology (GO) analysis and Kyoto Encyclopedia of Genes and Genomes pathway (KEGG) analysis were performed. A p level < 0.05 was considered statistically significant.R esults: Compared with the control group and baseline values, the CIE group showed a significant increase in ethanol intake. High-throughput sequencing revealed 399 significantly different circRNAs in CIE mice, including 150 up-regulated circRNAs and 249 down-regulated circRNAs. GO analysis showed that the most significantly enriched term for biological process, cellular component, and molecular function were GO:0050885, GO:0016020 and GO:0005515, respectively. The most enriched pathways in KEGG analysis were GABAergic synapse (mmu04727), followed by retrograde endocannabinoid (eCB) signaling (mmu04723) and morphine addiction (mmu05032). Among the circRNAs, RT-qPCR confirmed 14 upregulated and 13 downregulated circRNAs in the brain tissues with 9 upregulated and 10 downregulated circRNAs being observed in blood samples.C onclusions: Our study suggests that chronic ethanol exposure upregulates or downregulates circRNAs in the brain, which, in turn, could alter neurotransmitter release and signal transduction.

Diagnostic Performance of Circulating miRNAs and Extracellular Vesicles in Acute Ischemic Stroke

Background: Increased inflammation activates blood coagulation system, higher platelet activation plays a key role in the pathophysiology of ischemic stroke (IS). During platelet activation and aggregation process, platelets may cause increased release of several proinflammatory, and prothrombotic mediators, including microRNAs (miRNAs) and extracellular vesicles (EVs). In the current study we aimed to assess circulating miRNAs profile related to platelet function and inflammation and circulating EVs from platelets, leukocytes, and endothelial cells to analyse their diagnostic and predictive utility in patients with acute IS. Methods: The study population consisted of 28 patients with the diagnosis of the acute IS. The control group consisted of 35 age- and gender-matched patients on acetylsalicylic acid (ASA) therapy without history of stroke and/or TIA with established stable coronary artery disease (CAD) and concomitant cardiovascular risk factors. Venous blood samples were collected from the control group and patients with IS on ASA therapy (a) 24 h after onset of acute IS, (b) 7-days following index hospitalization. Flow cytometry was used to determine the concentration of circulating EVs subtypes (from platelets, leukocytes, and endothelial cells) in platelet-depleted plasma and qRT-PCR was used to determine several circulating plasma miRNAs (miR-19a-3p, miR-186-5p and let-7f). Results: Patients with high platelet reactivity (HPR, based on arachidonic acid-induced platelet aggregometry) had significantly elevated platelet-EVs (CD62+) and leukocyte-EVs (CD45+) concentration compared to patients with normal platelet reactivity at the day of 1 acute-stroke (p = 0.012, p = 0.002, respectively). Diagnostic values of baseline miRNAs and EVs were evaluated with receiver operating characteristic (ROC) curve analysis. The area under the ROC curve for miR-19a-3p was 0.755 (95% CI, 0.63–0.88) p = 0.004, for let-7f, it was 0.874 (95% CI, 0.76–0.99) p = 0.0001; platelet-EVs was 0.776 (95% CI, 0.65–0.90) p = 0.001, whereas for leukocyte-EVs, it was 0.715 (95% CI, 0.57–0.87) p = 0.008. ROC curve showed that pooling the miR-19a-3p expressions, platelet-EVs, and leukocyte-EVs concentration yielded a higher AUC than the value of each individual biomarker as AUC was 0.893 (95% CI, 0.79–0.99). Patients with moderate stroke had significantly elevated miR-19a-3p expression levels compared to patients with minor stroke at the first day of IS. (AUC: 0.867, (95% CI, 0.74–0.10) p = 0.001). Conclusion: Combining different biomarkers of processes underlying IS pathophysiology might be beneficial for early diagnosis of ischemic events. Thus, we believe that in the future circulating biomarkers might be used in the prehospital phase of IS. In particular, circulating plasma EVs and non-coding RNAs including miRNAs are interesting candidates as bearers of circulating biomarkers due to their high stability in the blood and making them highly relevant biomarkers for IS diagnostics.

MicroRNA let-7f alleviates vascular endothelial cell dysfunction via targeting HMGA2 under oxygen-glucose deprivation and reoxygenation

Stroke is a fatal disease with high disability and mortality and there is no credible treatment for stroke at present. Studies on stroke are extensively developed to explore the underlying mechanisms of ischemic and reperfusion injuries. Herein, we investigated the functions of microRNA let-7f (also termed let-7f-5p) in vascular endothelial cell dysfunction. The bEnd.3 cells were stimulated with oxygen-glucose deprivation and reoxygenation (OGD/R) to mimic cell injury in vitro. CCK-8 assays, flow cytometry and western blot analyses were conducted to examine the viability and apoptosis of bEnd.3 cells. Reverse transcription quantitative polymerase chain reaction analyses were employed to measure RNA expression. Endothelial cell permeability in vitro assay was employed to assess endothelial permeability of bEnd.3 cells, and expression levels of proteins associated with cell apoptosis or blood-brain barrier (BBB) were detected by western blot analyses. Luciferase reporter assay was conducted to explore the combination between let-7f and HMGA2. We found that OGD/R induced injuries on endothelial cells (bEnd.3) by decreasing cell viability and promoting cell apoptosis. Let-7f exhibited low expression in bEnd.3 cells under OGD/R. Let-7f overexpression increased the viability of bEnd.3 cells and inhibited cell apoptosis. In addition, the endothelial permeability of bEnd.3 cells was increased by OGD/R and reversed by let-7f overexpression. The levels of tight junction proteins (ZO-1 and occludin) were downregulated by OGD/R and then reversed by let-7f overexpression. Mechanistically, HMGA2 is a target gene of let-7f and its expression was negatively regulated by let-7f. Rescue assays revealed that HMGA2 overexpression reversed the effects of let-7f overexpression on cell viability, cell apoptosis, endothelial permeability, and BBB function. In conclusion, let-7f alleviates vascular endothelial cell dysfunction by downregulating HMGA2 expression under OGD/R.

MicroRNA Analysis of Human Stroke Brain Tissue Resected during Decompressive Craniectomy/Stroke-Ectomy Surgery

BACKGROUND

Signaling pathways mediated by microRNAs (miRNAs) have been identified as one of the mechanisms that regulate stroke progression and recovery. Recent investigations using stroke patient blood and cerebrospinal fluid (CSF) demonstrated disease-specific alterations in miRNA expression. In this study, for the first time, we investigated miRNA expression signatures in freshly removed human stroke brain tissue.

METHODS

Human brain samples were obtained during craniectomy and brain tissue resection in severe stroke patients with life-threatening brain swelling. The tissue samples were subjected to histopathological and immunofluorescence microscopy evaluation, next generation miRNA sequencing (NGS), and bioinformatic analysis.

RESULTS

miRNA NGS analysis detected 34 miRNAs with significantly aberrant expression in stroke tissue, as compared to non-stroke samples. Of these miRNAs, 19 were previously identified in stroke patient blood and CSF, while dysregulation of 15 miRNAs was newly detected in this study. miRNA direct target gene analysis and bioinformatics approach demonstrated a strong association of the identified miRNAs with stroke-related biological processes and signaling pathways.

CONCLUSIONS

Dysregulated miRNAs detected in our study could be regarded as potential candidates for biomarkers and/or targets for therapeutic intervention. The results described herein further our understanding of the molecular basis of stroke and provide valuable information for the future functional studies in the experimental models of stroke.

Aberrant DNA methylation and miRNAs in coronary artery diseases and stroke: a systematic review

Coronary artery disease (CAD) and ischemic stroke are the two most predominant forms of cardiovascular diseases (CVDs) caused by genetic, epigenetic and environmental risk factors. Although studies on the impact of 'epigenetics' in CVDs is not new, its effects are increasingly being realized as a key regulatory determinant that may drive predisposition, pathophysiology and therapeutic outcome. The most widely studied epigenetic risk factors are regulated by DNA methylation and miRNA expression. To keep pace with growing developments and discoveries, a comprehensive review was performed using Pubmed, Science Direct and Scopus databases to highlight the role of DNA methylation and miRNAs in CAD and stroke subjects. Network analysis was performed using ClueGO software and miRTargetLink database. We identified 32 studies of DNA methylation on CAD and stroke, of which, 6 studies showed differences in global DNA methylation, 10 studies reported the genome-wide difference in DNA methylation and 16 studies demonstrated altered DNA methylation at 14 candidate loci. The network analysis showed positive regulation of nitric oxide biosynthetic process, homocysteine metabolic process and negative regulation of lipid storage. About, 155 miRNAs were associated with CAD, stroke and related phenotypes in 83 studies. Interestingly, mir-223 hypomethylation and altered expression were associated with cerebral infarction and stroke. The target prediction for 18 common miRNAs between CAD and stroke showed strong interaction with SP3 and SP1 genes. This systematic review addresses the present knowledge on DNA methylation and miRNAs in CAD and stroke, whose abnormal regulation has been implicated in etiology or progression of the diseases.

The microRNA let-7b-5p Is Negatively Associated with Inflammation and Disease Severity in Multiple Sclerosis

The identification of microRNAs in biological fluids for diagnosis and prognosis is receiving great attention in the field of multiple sclerosis (MS) research but it is still in its infancy. In the present study, we observed in a large sample of MS patients that let-7b-5p levels in the cerebrospinal fluid (CSF) were highly correlated with a number of microRNAs implicated in MS, as well as with a variety of inflammation-related protein factors, showing specific expression patterns coherent with let-7b-5p-mediated regulation. Additionally, we found that the CSF let-7b-5p levels were significantly reduced in patients with the progressive MS compared to patients with relapsing-remitting MS and were negatively correlated with characteristic hallmark processes of the two phases of the disease. Indeed, in the non-progressive phase, let-7b-5p inversely associated with both central and peripheral inflammation; whereas, in progressive MS, the CSF levels of let-7b-5p negatively correlated with clinical disability at disease onset and after a follow-up period. Overall, our results uncovered, by the means of a multidisciplinary approach and multiple statistical analyses, a new possible pleiotropic action of let-7b-5p in MS, with potential utility as a biomarker of MS course.

Ischemia-reperfusion injury of brain induces endothelial-mesenchymal transition and vascular fibrosis via activating let-7i/TGF-βR1 double-negative feedback loop

Let-7i modulates the physical function and inflammation in endothelial cells (ECs). However, whether the let-7i of ECs involves in brain vasculature and ischemic stroke is unknown. Using inducible Cadherin5-Cre lineage-tracking mice, a loxp-RNA-sponge conditional knockdown of let-7 in ECs- induced increase of transforming growth factor-β receptor type 1 (TGF-βR1), endothelial-mesenchymal transition (endMT), vascular fibrosis, and opening of the brain-blood barrier (BBB). By this lineage-tracking mice, we found that ECs underwent endMT after transient middle cerebral artery occlusion (MCAO). Through specifically overexpressed let-7i in ECs, we found that it reduced TGF-βR1, endMT, and vascular fibrosis. Furthermore, this overexpression reduced the infarct volume and leakage of the BBB, and improved the neurological function. Further, the expression of let-7i decreased after MCAO, but was reversed by antagonist of TGF-βR1 or inhibition of Mek phosphorylation. And the inhibition of Mek attenuated the vascular fibrosis after MCAO. In summary, we concluded that ischemic stroke activates a let-7i/TGF-βR1 double-negative feedback loop, thereby inducing endMT and vascular fibrosis. These results suggest that endMT is a potential target for the treatment of cerebral vascular fibrosis.

Concise Review: Therapeutic Potential of the Mesenchymal Stem Cell Derived Secretome and Extracellular Vesicles for Radiation-Induced Lung Injury: Progress and Hypotheses

Radiation-induced lung injury (RILI) is a common complication in radiotherapy of thoracic tumors and limits the therapeutic dose of radiation that can be given to effectively control tumors. RILI develops through a complex pathological process, resulting in induction and activation of various cytokines, infiltration by inflammatory cells, cytokine-induced activation of fibroblasts, and subsequent tissue remodeling by activated fibroblasts, ultimately leading to impaired lung function and respiratory failure. Increasing evidence shows that mesenchymal stem cells (MSCs) may play a main role in modulating inflammation and immune responses, promoting survival and repair of damaged resident cells and enhancing regeneration of damaged tissue through soluble paracrine factors and therapeutic extracellular vesicles. Therefore, the use of the MSC-derived secretome and exosomes holds promising potential for RILI therapy. Here, we review recent progress on the potential mechanisms of MSC therapy for RILI, with an emphasis on soluble paracrine factors of MSCs. Hypotheses on how MSC derived exosomes or MSC-released exosomal miRNAs could attenuate RILI are also proposed. Problems and translational challenges of the therapies based on the MSC-derived secretome and exosomes are further summarized and underline the need for caution on rapid clinical translation. Stem Cells Translational Medicine 2019;8:344-354.

Monogenic, Polygenic, and MicroRNA Markers for Ischemic Stroke

Ischemic stroke (IS) is a leading disease with high mortality and disability, as well as with limited therapeutic window. Biomarkers for earlier diagnosis of IS have long been pursued. Family and twin studies confirm that genetic variations play an important role in IS pathogenesis. Besides DNA mutations found previously by genetic linkage analysis for monogenic IS (Mendelian inheritance), recent studies using genome-wide associated study (GWAS) and microRNA expression profiling have resulted in a large number of DNA and microRNA biomarkers in polygenic IS (sporadic IS), especially in different IS subtypes and imaging phenotypes. The present review summarizes genetic markers discovered by clinical studies and discusses their pathogenic molecular mechanisms involved in developmental or regenerative anomalies of blood vessel walls, neuronal apoptosis, excitotoxic death, inflammation, neurogenesis, and angiogenesis. The possible impact of environment on genetics is addressed as well. We also include a perspective on further studies and clinical application of these IS biomarkers.

MicroRNAs as Diagnostic and Prognostic Biomarkers in Ischemic Stroke-A Comprehensive Review and Bioinformatic Analysis

Stroke is the second-most common cause of death worldwide. The pathophysiology of ischemic stroke (IS) is related to inflammation, atherosclerosis, blood coagulation, and platelet activation. MicroRNAs (miRNAs) play important roles in physiological and pathological processes of neurodegenerative diseases and progression of certain neurological diseases, such as IS. Several different miRNAs, and their target genes, are recognized to be involved in the pathophysiology of IS. The capacity of miRNAs to simultaneously regulate several target genes underlies their unique value as diagnostic and prognostic markers in IS. In this review, we focus on the role of miRNAs as diagnostic and prognostic biomarkers in IS. We discuss the most common and reliable detection methods available and promising tests currently under development. We also present original results from bioinformatic analyses of published results, identifying the ten most significant genes (HMGB1, YWHAZ, PIK3R1, STAT3, MAPK1, CBX5, CAPZB, THBS1, TNFRSF10B, RCOR1) associated with inflammation, blood coagulation, and platelet activation and targeted by miRNAs in IS. Additionally, we created miRNA-gene target interaction networks based on Gene Ontology (GO) information derived from publicly available databases. Among our most interesting findings, miR-19a-3p is the most widely modulated miRNA across all selected ontologies and might be proposed as novel biomarker in IS to be tested in future studies.

LIN28B/let-7 axis mediates pulmonary inflammatory response induced by diesel exhaust particle exposure in mice

Exposure to diesel exhaust particle (DEP) is closely related to inflammatory response in respiratory system. To understand the underlying molecular mechanism by which DEP induces pulmonary inflammatory response, we conducted DEP exposure experiments in vivo and in vitro. In vivo, each mouse was exposed to DEP suspension (100 μg of DEP) or vehicle only once in single intra-tracheal instillation (IT) section, or was exposed to DEP suspension (12.5 μg or 50 μg of DEP) or vehicle 12 times in repeated IT section. DEP exposure induced significant pathological injuries with substantial neutrophils infiltration and the increased level of pro-inflammatory cytokine IL-6 in mouse lungs. Consistently, elevated IL6 mRNA level was also observed in DEP treatment group (100 μg/ml) in vitro. In addition, DEP exposure exerted the similar influence on the expression of let-7d and let-7g microRNAs in vivo and in vitro. To verify the possible role of LIN28B/let-7 axis in the regulation of IL6 expression following DEP exposure, we applied RNAi technology in vitro, and found increased IL6 mRNA expression was alleviated or neutralized in DEP exposure groups after LIN28B silencing or after let-7d or let-7g over-expression. Taken together, we conclude that LIN28B/let-7 axis might be involved in inflammatory response induced by DEP exposure.

Mitochondrial dysfunction induces NLRP3 inflammasome activation during cerebral ischemia/reperfusion injury

Background

Nod-like receptor protein 3 (NLRP3) inflammasome is a crucial factor in mediating inflammatory responses after cerebral ischemia/reperfusion (I/R), but the cellular location of NLRP3 inflammasome in cerebral I/R has yet come to a conclusion, and there is still no specific evidence to state the relationship between mitochondria and the NLRP3 inflammasome in cerebral I/R.

Methods

In the present study, we detected the cellular localization of NLRP3 inflammasomes in a transient middle cerebral artery occlusion (tMCAO) rat model and a transwell co-culture cell system under oxygen-glucose deprivation/reoxygenation (OGD/R) conditions. Then, we investigated the relationship between mitochondrial dysfunction and the activation of NLRP3 inflammasomes in different cell types after OGD/R and cerebral I/R injury.

Results

Our results showed that NLRP3 inflammasomes were first activated in microglia soon after cerebral I/R injury onset and then were expressed in neurons and microvascular endothelial cells later, but they were mainly in neurons. Furthermore, mitochondrial dysfunction played an important role in activating NLRP3 inflammasomes in microglia after OGD/R, and mitochondrial protector could inhibit the activation of NLRP3 inflammasomes in cerebral I/R rats.

Conclusion

Our findings may provide novel insights into the cell type-dependent activation of NLRP3 inflammasomes at different stages of cerebral I/R injury and the role of mitochondrial dysfunction in activating the NLRP3 inflammasome pathway.

Electronic supplementary material

The online version of this article (10.1186/s12974-018-1282-6) contains supplementary material, which is available to authorized users.

Potential biomarkers for predicting hemorrhagic transformation of ischemic stroke

Reperfusion therapy contributes to better clinical outcomes in patients with acute ischemic stroke but carries a more significant risk of hemorrhagic transformation (HT) compared to supportive care. Once HT occurs, the outcome is usually poor and this causes a dilemma in the treatment of ischemic stroke. Consequently, early prediction of HT would be extremely helpful for guiding precise treatment of ischemic stroke. In this review, we focus on summarizing biomarkers of HT and elucidating possible mechanisms so as to identify potential biomarkers for predicting HT.

Combined effects of age and polymorphisms in Notch3 in the pathogenesis of cerebral infarction disease

Cerebral infarction disease is a severe hypoxic ischemic tissue necrosis in the brain, often leading to long-term functional disability and residual impairments. The Notch signaling pathway plays key roles in proliferation and survival of the stem/progenitor cells of the central and peripheral nervous systems. Notch3 is an important member of the pathway, but the relationships between the genetic abnormalities and cerebral infarction disease still remain unclear. The aim of this work was to evaluate variations in Notch3 gene for their possible associations with the cerebral infarction disease. We sequenced the Notch3 gene for 260 patients with cerebral infarction disease, 300 normal controls with old ages and 300 normal controls with younger ages, and identified the variations. The statistical analyses were conducted using Chi-Square Tests as implemented in SPSS (version 19.0). The Hardy-Weinberg equilibrium test of the population was carried out using the online software OEGE. Six variations, including rs1044116, rs1044009, rs1044006, rs10408676, rs1043996 and rs16980398 within or near the Notch3 gene, were found. The genetic heterozygosity of rs1044116, rs1044009, rs1044006, and rs1043996 was very high, whereas that of rs10408676 and rs16980398 was very low. Statistical analyses showed that rs1044009 and rs1044006 were associated with the risk of cerebral infarction disease in the Chinese Han agedness population. The SNPs rs1044009 and rs1044006 in the Notch3 gene were associated with the risk of cerebral infarction diseases in the Chinese Han agedness population.

Circulating miRNAs in Murine Experimental Endometriosis

Endometriosis is a chronic disease that commonly affects women of reproductive age; however, diagnosis is often delayed due to lack of appreciation of early signs and symptoms. Development of a noninvasive biomarker would significantly reduce delays in diagnosis and treatment. Circulating microRNAs (miRNAs) have been implicated as biomarkers for several diseases including endometriosis. Here, we use an miRNA array to investigate differential miRNA abundance in the serum of mice after induction of experimental endometriosis. let-7a-5p was decreased in the serum of mice with endometriosis. let-7b-5p, c-5p, and e-5p also showed a trend toward downregulation. Serum let-7 family miRNA shows similar dysregulation in endometriosis in both humans and mice. Diminished circulating let-7 implies a complex regulation that potentially involves multiple organs. Further investigation is necessary to determine the functional roles of let-7 miRNAs in this disease.