Circulating MicroRNA Levels Indicate Platelet and Leukocyte Activation in Endotoxemia Despite Platelet P2Y12 Inhibition

Abstract

There is evidence for the effects of platelet inhibition on innate immune activation. Circulating microRNAs (miRNAs) have been implicated as markers of platelet and leukocyte activation. In the present study, we assessed the effects of P2Y 12 inhibitors on platelet and leukocyte miRNAs during endotoxemia. Healthy volunteers were randomly assigned to receive oral ticagrelor (n = 10), clopidogrel (n = 8) or no drug (n = 8) for one week, followed by an intravenous bolus of 2 ng/kg endotoxin. Serum was collected at baseline, after one week of antiplatelet treatment and 6 and 24 h after endotoxin administration. MiRNAs were screened using LNA-based qPCR, followed by TaqMan-qPCR validation of candidates. Clinical validation was performed in 41 sepsis patients. Platelet-enriched miR-197, miR-223 and miR-223* were decreased in volunteers following antiplatelet therapy. Endotoxin increased platelet miRNAs, whilst the opposite effect was seen for leukocyte-enriched miR-150. Neither of these endotoxin-mediated effects were altered by P2Y 12 inhibitors. Sepsis patients with fatal outcomes (n = 12) had reduced miR-150 levels compared with survivors (n = 29). In conclusion, we show that miR-150 is downregulated in experimental endotoxemia and can predict survival in sepsis but is unaffected by P2Y 12 inhibition. While P2Y 12 inhibition reduces platelet-associated miRNAs in healthy volunteers, it fails to attenuate the response of platelet miRNAs to endotoxemia.

Platelet “-omics” in health and cardiovascular disease

“…Transcriptomics provides snapshots of the entire landscape of RNA transcripts in a given cell type or tissue at a given time and condition. Besides transcriptomic studies on coding mRNAs, the noncoding transcriptome (microRNAs, YRNAs, circular RNAs, long noncoding RNAs) is also gaining attention for its role as a marker of platelet function in various conditions [111,84]. Microarrays and RNA-seq are the two predominant methods for transcriptomic analyses.…”

Multifaceted Functions of Platelets in Cancer: From Tumorigenesis to Liquid Biopsy Tool and Drug Delivery System

“…Transcriptomics analysis consists of studying the entire landscape of RNA transcripts in a cell type or tissue. In addition to the transcriptome studies on coding mRNAs, the noncoding transcriptome (microRNAs, YRNAs, circular RNAs, long noncoding RNAs) is also gaining attention for its role as platelet function marker in various conditions [ 144 , 145 ]. Several studies have shown the association between the transcriptomic profile of platelets with different pathological conditions, such as inflammatory [ 146 ], hematological [ 147 ], oncologic [ 148 ], autoimmune [ 149 ], metabolic [ 150 ], nephrological [ 151 ], and cardiovascular diseases.…”

miR-146a in Cardiovascular Diseases and Sepsis: An Additional Burden in the Inflammatory Balance?

“…Interestingly, miR-146a protection in endotoxin tolerance was also observed in morphine treatment, the main analgesic used in postoperative pain management, and a prevalent recreational drug with well-known adverse effects on the immune system 86 miR-146a dysregulation has also been described in sepsis in humans. With an interesting approach, Braza-Boils et al have described that miR-146a was significantly down regulated in plasma after LPS treatment in an experimental human model of low-dose endotoxemia in volunteers 94 . These results suggest that LPS alone could also be inducing changes in miR-146a expression in humans.…”

“…How and when the samples are obtained also accounts for the large variability observed between studies. For example, drug treatment in CVD or in sepsis can modified miRNA expression levels and may confound the results as shown in several works from Mayr's lab among others 94,117,121 . Thus,…”