The function and mechanism of microRNA-92a-3p in lipopolysaccharide-induced acute lung injury

MiR-92a-3p Promotes Renal Injury and Fibrosis Through Facilitating M1 Macrophage Polarization via Targeting LIN28A

Infiltrated and activated M1 macrophages play a role in kidney injury and fibrosis during chronic kidney disease (CKD) progression. However, the specific ways that M1 macrophage polarization contributes to renal fibrosis are not fully understood. The study seeks to investigate how miR-92a-3p regulates M1 macrophage polarization and its connection to renal fibrosis in the development of CKD. Our results revealed that miR-92a-3p overexpression increased M1-macrophage activation, iNOS, IL-6, and TNF-alpha expression in RAW264.7 upon LPS stimulation. LIN28A overexpression reversed these effects. Moreover, miR-92a-3p overexpression in RAW264.7 exacerbated NRK-52E cell apoptosis induced by LPS, but LIN28A overexpression counteracted this effect. MiR-92a-3p knockout in unilateral ureteral obstruction (UUO) C57BL/6 mice led to reduced renal infiltration and fibrosis, accompanied by decreased iNOS, alpha-SMA, IL-6, TNF-alpha, and increased LIN28A. In summary, our findings suggest that miR-92a-3p may play a role in promoting renal injury and fibrosis both in vitro and in vivo. This effect is potentially achieved by facilitating M1 macrophage polarization through the targeting of LIN28A.

Decrease of exosomal miR-21-5p and the increase of CD62p+ exosomes are associated with the development of sepsis in polytraumatized patients

Sepsis as a severe systemic inflammation leads oftentimes to organ dysfunction and subsequently to death. In polytrauma patients, septic complications represent with 45% the predominant cause of late death and are responsible for extremely high costs in the healthcare system. Therefore, clinicians have to detect as early as possible the begin of sepsis to improve the patient's outcome. One new promising diagnostic tool to diagnose septic complications in polytraumatized patients are exosomes. Plasma samples from polytraumatized patients (Injury Severity Score (ISS) ≥16) which developed sepsis (n = 10) and without sepsis (n = 10), were collected at emergency room (ER), 24h and 5 days after trauma. The EVs subpopulations were investigated by a bead-based multiplex flow cytometry measurement of surface epitopes and were compared with plasma EVs from healthy controls (n = 10). Moreover, exosomal cytokine concentrations were measured via high-sensitive ELISA and were correlated with systemic concentrations. For miRNA cargo analysis, we analysed the miRNAs miR-1298-5p, miR-1262, miR-125b-5p, miR-92a-3p, miR-93-5p, miR-155-5p and miR-21-5p and compared their exosomal concentrations by means of RT-qPCR. CD62p + exosomes were significantly increased in septic polytrauma-patients (p ≤ 0.05), while CD40+exosomes, as well as CD49e + exosomes were diminished (p ≤ 0.05). Furthermore, we observed that the exosomal IL-6 concentration reflects the systemic IL-6 concentration (r2 = 0.63) and did not significantly alter between patients with and without sepsis. The exosomal IL-10 concentration seemed to be constant in all patients and healthy controls. We observed that a decrease of miR-21-5p in exosomes was associated with the development of sepsis (p ≤ 0.05), while exosomal miR-93-5p, miR-155-5p and miR-92a-3p were not specifically altered in septic patients. Taken together, the present study in polytraumatized patients demonstrated that the development of sepsis is associated with an increase of CD62p + exosomes. Furthermore, the exosomal cargo was changed in septic patients: miR-21-5p was diminished.

Expression of MicroRNAs in Sepsis-Related Organ Dysfunction: A Systematic Review

Sepsis is a critical condition characterized by increased levels of pro-inflammatory cytokines and proliferating cells such as neutrophils and macrophages in response to microbial pathogens. Such processes lead to an abnormal inflammatory response and multi-organ failure. MicroRNAs (miRNA) are single-stranded non-coding RNAs with the function of gene regulation. This means that miRNAs are involved in multiple intracellular pathways and thus contribute to or inhibit inflammation. As a result, their variable expression in different tissues and organs may play a key role in regulating the pathophysiological events of sepsis. Thanks to this property, miRNAs may serve as potential diagnostic and prognostic biomarkers in such life-threatening events. In this narrative review, we collect the results of recent studies on the expression of miRNAs in heart, blood, lung, liver, brain, and kidney during sepsis and the molecular processes in which they are involved. In reviewing the literature, we find at least 122 miRNAs and signaling pathways involved in sepsis-related organ dysfunction. This may help clinicians to detect, prevent, and treat sepsis-related organ failures early, although further studies are needed to deepen the knowledge of their potential contribution.