Role of miR-449a in the Activation and Metabolism of CD4+ T Cells

MicroRNAs as theranostic markers in cardiac allograft transplantation: from murine models to clinical practice

Congestive heart failure affects about 23 million people worldwide, and cardiac allograft transplantation remains one of the last options for patients with terminal refractory heart failure. Besides the infectious or oncological complications, the prognosis of patients after heart transplantation is affected by acute cellular or antibody-mediated rejection and allograft vasculopathy development. Current monitoring of both conditions requires the performance of invasive procedures (endomyocardial biopsy sampling and coronary angiography or optical coherence tomography, respectively) that are costly, time-demanding, and non-comfortable for the patient. Within this narrative review, we focus on the potential pathophysiological and clinical roles of microRNAs (miRNAs, miRs) in the field of cardiac allograft transplantation. Firstly, we provide a general introduction about the status of cardiac allograft function monitoring and the discovery of miRNAs as post-transcriptional regulators of gene expression and clinically relevant biomarkers found in the extracellular fluid. After this general introduction, information from animal and human studies are summarized to underline the importance of miRNAs both in the pathophysiology of the rejection process, the possibility of its modulation by altering miRNAs levels, and last but not least, about the use of miRNAs in the clinical practice to diagnose or predict the rejection occurrence.

Assessment of expression profile of microRNAs in multiple sclerosis patients treated with fingolimod

Fingolimod is an immunotherapeutic drug approved in certain countries as first-line therapy for relapsing-remitting multiple sclerosis (RRMS). The drug has been shown to alter the expression of several coding and non-coding genes. In the current study, we assessed the expression of miR-506-3p, miR-217, miR-381-3p, miR-1827, miR-449a and miR-655-3p in peripheral blood of patients with RRMS undergoing treatment with fingolimod compared with healthy controls. We also compared the expression of these miRNAs between fingolimod responders and non-responders to determine their relevance with regard to response to fingolimod. Expression of miR-381-3p was significantly higher in responders than in controls (RE difference = 3.903, P = 0.005), while expression of miR-655-3p was significantly lower in both responders and non-responders compared with controls (RE difference = -1.03, P = 0.014; RE difference = -1.41, P < 0.0001, respectively). No difference was found in the expression of other miRNAs between study subgroups. In addition, there was no significant difference in the expression of any miRNA between responders and non-responders. Although there were significant pairwise correlations between expression levels of all of the assessed miRNAs in controls, MS patients exhibited differences in correlation patterns. Expression of miR-381-3p was correlated with age in responders. However, expression of other miRNAs did not correlate with age in any study subgroup. The current study indicates a possible role for miR-655-3p and miR-381-3p in the pathogenesis of MS or possible effects of fingolimod on the expression of these miRNAs. Future studies are needed to verify these results in larger patient populations.