Exosomal MicroRNA for Detection of Cardiac Sarcoidosis

Exosomal miRNAs as Participators of Hexavalent Chromium-Induced Genotoxicity and Immunotoxicity: A Two-Stage Population Study

Genotoxic and immunosuppressive characteristics are central to the carcinogenic profile of hexavalent chromium [Cr(VI)], with dysregulation of circulating exosomal miRNA potentially acting as oncogenes or tumor suppressors or participating in the carcinogenic landscape of heavy metals through immunomodulation. In this two-stage epidemiological investigation, we unveiled for the first time the perturbations of exosomal miRNAs among individuals exposed to Cr(VI), alongside their significant correlations with biomarkers of genetic injury (γ-H2AX positivity in circulating lymphocytes and the urinary 8-OHdG levels) and immunological indicators (immunosuppressive PD-1 expression), which was supported by validation in an external cohort. Employing a support vector machine model, we discerned that exosomal miRNAs, particularly miR-4467, miR-345-5p, miR-144-3p, and miR-206, exhibited a remarkable capacity to delineate the genetic damage stratum within the population with high precision, and the target genes predicted of these miRNAs further elucidated their intricate regulatory interplay with the effector biomarkers. Additionally, employing a Bayesian mediation framework, we observed the intermediary function of miR-4467 in the nexus between chromium exposure and the escalation of urinary 8-OHdG levels (mediation effect: 0.47, P < 0.05). Although our findings suggested a link between extracellular miRNAs and immunosuppressive biomarkers, this association did not achieve validation in the external cohort, possibly due to population heterogeneity. Collectively, this study advanced our understanding of the epigenetic orchestration of health hazards of Cr(VI) by exosomal miRNAs, shedding light on their expression signatures and their intricate interplay with Cr(VI)-induced genetic and immunological perturbations, thus providing novel perspectives on the toxic pathways of heavy metals.

Examination of eQTL Polymorphisms Associated with Increased Risk of Progressive Complicated Sarcoidosis in European and African Descent Subjects

Background

A limited pool of SNPs are linked to the development and severity of sarcoidosis, a systemic granulomatous inflammatory disease. By integrating genome-wide association studies (GWAS) data and expression quantitative trait loci (eQTL) single nuclear polymorphisms (SNPs), we aimed to identify novel sarcoidosis SNPs potentially influencing the development of complicated sarcoidosis.

Methods

A GWAS (Affymetrix 6.0) involving 209 African-American (AA) and 193 European-American (EA, 75 and 51 complicated cases respectively) and publicly-available GWAS controls (GAIN) was utilized. Annotation of multi-tissue eQTL SNPs present on the GWAS created a pool of ~46,000 eQTL SNPs examined for association with sarcoidosis risk and severity (Logistic Model, Plink). The most significant EA/AA eQTL SNPs were genotyped in a sarcoidosis validation cohort (n=1034) and cross-validated in two independent GWAS cohorts.

Results

No single GWAS SNP achieved significance (p<1x10-8), however, analysis of the eQTL/GWAS SNP pool yielded 621 eQTL SNPs (p<10-4) associated with 730 genes that highlighted innate immunity, MHC Class II, and allograft rejection pathways with multiple SNPs validated in an independent sarcoidosis cohort (105 SNPs analyzed) (NOTCH4, IL27RA, BTNL2, ANXA11, HLA-DRB1). These studies confirm significant association of eQTL/GWAS SNPs in EAs and AAs with sarcoidosis risk and severity (complicated sarcoidosis) involving HLA region and innate immunity.

Conclusion

Despite the challenge of deciphering the genetic basis for sarcoidosis risk/severity, these results suggest that integrated eQTL/GWAS approaches may identify novel variants/genes and support the contribution of dysregulated innate immune responses to sarcoidosis severity.

Paracrine effects of mir-210-3p on angiogenesis in hypoxia-treated c-kit-positive cardiac cells

Objective: Treatment with c-kit-positive cardiac cells (CPCs) has been shown to improve the prognosis of ischemic heart disease. MicroRNAs (miRNAs) confer protection by enhancing the cardiac repair process, but their specific functional mechanisms remain unclear. This study aimed to screen for differentially expressed miRNAs in CPCs under hypoxia and explore their effects on the function of CPCs.Methods: We harvested CPCs from C57 adult mice and later performed a high-throughput miRNA sequencing for differential expression profiling analysis. Subsequently, we intervened with the differentially expressed gene miR-210-3p in CPCs and detected changes in the secretion of angiogenesis-related factors through a protein-chip analysis. Finally, we applied CPC supernatants of different groups as conditioned medium to treat mouse cardiac microvascular endothelial cells (CMECs) and further investigated the functional effects of miR-210-3p on c-kit+CPCs under ischemia and hypoxia conditions.Results: The miR-210-3p was highly increased in hypoxia-treated CPCs. Protein-chip detection revealed that CPCs expressed cytokines such as FGF basic, angiogenin, and vascular endothelial growth factor (VEGF) and that hypoxia enhanced their release. Silencing miR-210-3p resulted in a reduction in the release of these angiogenesis-related factors. In addition, the conditioned medium of hypoxia-treated CPCs promoted the proliferation, migration, and tube-forming capabilities of CMECs. In contrast, the conditioned media of CPCs with silenced miR-210-3p after hypoxia decreased the proliferation, migration, and tube-forming ability of CMEC.Conclusions: The CPCs exert proangiogenic effects via paracrine pathways mediated by miR-210-3p. Upregulation of miR-210-3p in hypoxia-treated CPCs may enhance their paracrine function by regulating the secretion of angiogenic factors, thereby promoting angiogenesis in ischemic heart disease.

The Role of microRNAs in Inflammation

Inflammation is a biological response of the immune system to various insults, such as pathogens, toxic compounds, damaged cells, and radiation. The complex network of pro- and anti-inflammatory factors and their direction towards inflammation often leads to the development and progression of various inflammation-associated diseases. The role of small non-coding RNAs (small ncRNAs) in inflammation has gained much attention in the past two decades for their regulation of inflammatory gene expression at multiple levels and their potential to serve as biomarkers and therapeutic targets in various diseases. One group of small ncRNAs, microRNAs (miRNAs), has become a key regulator in various inflammatory disease conditions. Their fine-tuning of target gene regulation often turns out to be an important factor in controlling aberrant inflammatory reactions in the system. This review summarizes the biogenesis of miRNA and the mechanisms of miRNA-mediated gene regulation. The review also briefly discusses various pro- and anti-inflammatory miRNAs, their targets and functions, and provides a detailed discussion on the role of miR-10a in inflammation.

A Review on the Evolving Roles of MiRNA-Based Technologies in Diagnosing and Treating Heart Failure

MiRNA-regulated processes are pivotal in cardiovascular homeostasis and disease. These short non-coding RNAs have ideal properties that could be utilized as potential biomarkers; moreover, their functions as post-transcriptional regulators of mRNA make them interesting therapeutic targets. In this review, we summarize the current state of miRNA-based biomarkers in a variety of diseases leading to heart failure, as well as provide an outlook on developing miRNA-based therapies in the heart failure field.

Circulating exosomal microRNA expression patterns distinguish cardiac sarcoidosis from myocardial ischemia

Objective

Cardiac sarcoidosis is difficult to diagnose, often requiring expensive and inconvenient advanced imaging techniques. Circulating exosomes contain genetic material, such as microRNA (miRNA), that are derived from diseased tissues and may serve as potential disease-specific biomarkers. We thus sought to determine whether circulating exosome-derived miRNA expression patterns would distinguish cardiac sarcoidosis (CS) from acute myocardial infarction (AMI).

Methods

Plasma and serum samples conforming to CS, AMI or disease-free controls were procured from the Biologic Specimen and Data Repository Information Coordinating Center repository and National Jewish Health. Next generation sequencing (NGS) was performed on exosome-derived total RNA (n = 10 for each group), and miRNA expression levels were compared after normalization using housekeeping miRNA. Quality assurance measures excluded poor quality RNA samples. Differentially expressed (DE) miRNA patterns, based upon >2-fold change (p < 0.01), were established in CS compared to controls, and in CS compared to AMI. Relative expression of several DE-miRNA were validated by qRT-PCR.

Results

Despite the advanced age of the stored samples (~5–30 years), the quality of the exosome-derived miRNA was intact in ~88% of samples. Comparing plasma exosomal miRNA in CS versus controls, NGS yielded 18 DE transcripts (12 up-regulated, 6 down-regulated), including miRNA previously implicated in mechanisms of myocardial injury (miR-92, miR-21) and immune responses (miR-618, miR-27a). NGS further yielded 52 DE miRNA in serum exosomes from CS versus AMI: 5 up-regulated in CS; 47 up-regulated in AMI, including transcripts previously detected in AMI patients (miR-1-1, miR-133a, miR-208b, miR-423, miR-499). Five miRNAs with increased DE in CS included two isoforms of miR-624 and miR-144, previously reported as markers of cardiomyopathy.

Conclusions

MiRNA patterns of exosomes derived from CS and AMI patients are distinct, suggesting that circulating exosomal miRNA patterns could serve as disease biomarkers. Further studies are required to establish their specificity relative to other cardiac disorders.

Potential use of biomarkers for the clinical evaluation of sarcoidosis

Sarcoidosis is a systemic granulomatous disease of unknown etiology and pathogenesis with a heterogeneous clinical presentation. In the appropriate clinical and radiological context and with the exclusion of other diagnoses, the disease is characterized by the pathological presence of non-caseating epithelioid cell granulomas. Sarcoidosis is postulated to be a multifactorial disease caused by chronic antigenic stimulation. The immunopathogenesis of sarcoidosis encompasses a complex interaction between the host, genetic factors and postulated environmental and infectious triggers, which result in granuloma development.The exact pathogenesis of the disease has yet to be elucidated, but some of the inflammatory pathways that play a key role in disease progression and outcomes are becoming apparent, and these may form the logical basis for selecting potential biomarkers.Biomarkers are biological molecules that are altered pathologically. To date, there exists no single reliable biomarker for the evaluation of sarcoidosis, either diagnostically or prognostically but new candidates are emerging. A diagnosis of sarcoidosis ideally requires a biopsy confirming non-caseating granulomas, but the likelihood of progression that requires intervention remains unpredictable. These challenging aspects could be potentially resolved by incorporating biomarkers into clinical practice for both diagnosis and monitoring disease activity.This review outlines the current knowledge on sarcoidosis with an emphasis on pulmonary sarcoidosis, and delineates the understanding surrounding the implication of biomarkers for the clinical evaluation of sarcoidosis.

Paeonol inhibits NLRP3 mediated inflammation in rat endothelial cells by elevating hyperlipidemic rats plasma exosomal miRNA-223

Atherosclerosis (AS) is a multifactorial chronic inflammatory disease, and hyperlipidemia is the important factors leading to AS, which can cause vascular endothelial dysfunction. Paeonol (Pae) is a potential therapeutic drug for AS, and we have previously shown that Pae regulated the expression of monocytes-derived exosomal microRNA-223 (miR-223). However, the mechanisms of the anti-AS effect of Pae are still not fully understood. In this study, we aim to investigate if Pae could inhibit NLRP3 inflammasome mediated inflammation via elevating hyperlipidemic rats plasma-derived exosomal miR-223. We used high-fat-diet induced hyperlipidemic rats as model for further investigation. Rats were treated with Pae (75, 150 or 300 mg/kg) orally, and then exosomes were isolated from hyperlipidemic rat plasma by ultracentrifugation. In vivo experiments confirmed that Pae markedly reduced serum TC, TG, IL-1β, and IL-6 levels. Both CCK-8 and trypan blue staining showed that the survival rate of rat aortic endothelial cells (RAECs) in the Pae-exo group was higher than that in the model group. Also, Pae-exo dose-dependently increased the survival rate of RAECs and reduced inflammatory cytokines level (IL-1β, and IL-6). Furthermore, Pae-exo successfully increased the expression of exosomal miR-223 and relieved inflammatory secretion. Finally, decreased expression of NLRP3, ASC, caspase-1 and ICAM-1 indicated that Pae-exo attenuated inflammatory reaction of RAECs by suppressing NLRP3 signaling pathway. Altogether, our results showed that Pae inhibited the downstream NLRP3 inflammasome pathway by increasing the level of miR-223 in plasma derived exosomes of hyperlipidemic rats, providing new insights in the treatment of AS with the use of Pae.

Review: Contrast-enhanced magnetic resonance in the diagnosis and management of cardiac sarcoidosis

Sarcoidosis is a relatively rare inflammatory condition which potentially carries high morbidity and substantial mortality. Due to the fact that it does not subject patients to ionizing radiation, has high temporal, spatial and contrast resolutions, cardiovascular magnetic resonance imaging (CMR) has become an important diagnostic and prognostic modality in the evaluation for cardiac involvement in this condition. This review provides relevant clinical and pathophysiological background on cardiac sarcoidosis, whilst detailing the role of CMR imaging in the diagnosis, and management of this condition.

Exosomal non-coding RNAs (Exo-ncRNAs) in cardiovascular health

Extracellular vesicles (EVs) play a role in the pathophysiological processes and in different diseases, including cardiovascular disease. Out of several categories of EVs, exosomes (smallest - 30 to 150 nm) are gaining most of the focus as the next generation of biomarkers and in therapeutic strategies. This is because exosomes can be differentiated from other types of EVs based on the expression of tetraspanin molecules on the surface. More importantly, exosomes can be traced back to the cell of origin by identifying the unique cellular marker(s) on the exosomal surface. Recently, several researchs have demonstrated an important and underappreciated mechanism of paracrine cell-cell communication involving exosomal transfer, and its subsequent functional impact on recipient cells. Exosomes are enriched in proteins, mRNAs, miRNAs, and other non-coding RNAs, which can potentially alter myocardial function. Additionally, different stages of tissue damage can also be identified by measuring these bioactive molecules in the circulation. There are several aspects of this new concept still unknown. Therefore, in this review, we have summarized the knowledge we have so far and highlighted the potential of this novel concept of next generation biomarkers and therapeutic intervention.

Myocarditis: somethings old and something new

"Since the pathological conditions take place at the cellular level, viral myocarditis and postinfectious autoimmunity can be suggested but not diagnosed clinically. All clinical methods including imaging techniques are misleading if infectious agents are involved. Accurate diagnosis demands simultaneous histologic, immunohistochemical, and molecular biological workup of the tissue. If the primary infectious or immune-mediated causes of the disease are carefully defined by clinical and biopsy-based tools, specific antiviral treatment options in addition to basic symptomatic therapy are available under certain conditions. These may allow a tailored cause-specific treatment that improves symptoms and prognosis of patients with acute and chronic disease." Uwe Kühl; Heinz-Peter SchultheissViral myocarditis.Swiss Medical Weekly. 144():w14010, JAN 2014 DOI:10.4414/smw.2014.14010.

A Circulating MicroRNA Signature Serves as a Diagnostic and Prognostic Indicator in Sarcoidosis

MicroRNAs (miRNAs) act as post-transcriptional regulators of gene expression. In sarcoidosis, aberrant miRNA expression may enhance immune responses mounted against an unknown antigenic agent. We tested whether a distinct miRNA signature functions as a diagnostic biomarker and explored its role as an immune modulator in sarcoidosis. The expression of miRNAs in peripheral blood mononuclear cells from subjects who met clinical and histopathologic criteria for sarcoidosis was compared with that observed in matched controls in the ACCESS (A Case Controlled Etiologic Study of Sarcoidosis) study. Signature miRNAs were determined by miRNA microarray analysis and validated by quantitative RT-PCR. Microarray analysis identified 54 mature, human feature miRNAs that were differentially expressed between the groups. Significant feature miRNAs that distinguished subjects with sarcoidosis from controls were selected by means of probabilistic models adjusted for clinical variables. Eight signature miRNAs were chosen to verify the diagnosis of sarcoidosis in a validation cohort, and distinguished subjects with sarcoidosis from controls with a positive predictive value of 88%. We identified both novel and previously described genes and molecular pathways associated with sarcoidosis as targets of these signature miRNAs. Additionally, we demonstrate that signature miRNAs (hsa-miR-150-3p and hsa-miR-342-5p) are significantly associated with reduced lymphocytes and airflow limitations, both of which are known markers of a poor prognosis. Together, these findings suggest that a circulating miRNA signature serves as a noninvasive biomarker that supports the diagnosis of sarcoidosis. Future studies will test the miRNA signature as a prognostication tool to identify unfavorable changes associated with poor clinical outcomes in sarcoidosis.