Peripartum cardiomyopathy (PPCM) is a life-threatening heart disease developing towards the end of pregnancy or in the months following delivery in previously healthy women in terms of cardiac disease. Enhanced oxidative stress and the subsequent cleavage of the nursing hormone Prolactin into an anti-angiogenic 16 kDa subfragment emerged as a potential causal factor of the disease. We established a prospective registry with confirmed PPCM present in 115 patients (mean baseline left ventricular ejection fraction, LVEF: 27 ± 9 %). Follow-up data (6 ± 3 months) showed LVEF improvement in 85 % and full recovery in 47 % while 15 % failed to recover with death in 2 % of patients. A positive family history of cardiomyopathy was present in 16.5 %. Pregnancy-associated hypertension was associated with a better outcome while a baseline LVEF ≤ 25 % was associated with a worse outcome. A high recovery rate (96 %) was observed in patients obtaining combination therapy with beta-blocker, angiotensin-converting enzyme (ACE) inhibitors/angiotensin-receptor-blockers (ARBs) and bromocriptine. Increased serum levels of Cathepsin D, the enzyme that generates 16 kDa Prolactin, miR-146a, a direct target of 16 kDa Prolactin, N-terminal-pro-brain-natriuretic peptide (NT-proBNP) and asymmetric dimethylarginine (ADMA) emerged as biomarkers for PPCM. In conclusion, low baseline LVEF is a predictor for poor outcome while pregnancy-induced hypertensive disorders are associated with a better outcome in this European PPCM cohort. The high recovery rate in this collective is associated with a treatment concept using beta-blockers, ACE inhibitors/ARBs and bromocriptine. Increased levels of Cathepsin D activity, miR-146a and ADMA in serum of PPCM patients support the pathophysiological role of 16 kDa Prolactin for PPCM and may be used as a specific diagnostic marker profile.Electronic supplementary materialThe online version of this article (doi:10.1007/s00395-013-0366-9) contains supplementary material, which is available to authorized users.

BackgroundMicroRNAs (miRNAs) are endogenously expressed small non-coding RNAs that regulate gene expression at post-transcriptional level. The recent discovery of the involvement of these RNAs in the control of angiogenesis renders them very attractive in the development of new approaches for restoring the angiogenic balance. Whereas miRNA-21 has been demonstrated to be highly expressed in endothelial cells, the potential function of this miRNA in angiogenesis has never been investigated.Methodology/Principal FindingsWe first observed in endothelial cells a negative regulation of miR-21 expression by serum and bFGF, two pro-angiogenic factors. Then using in vitro angiogenic assays, we observed that miR-21 acts as a negative modulator of angiogenesis. miR-21 overexpression reduced endothelial cell proliferation, migration and the ability of these cells to form tubes whereas miR-21 inhibition using a LNA-anti-miR led to opposite effects. Expression of miR-21 in endothelial cells also led to a reduction in the organization of actin into stress fibers, which may explain the decrease in cell migration. Further mechanistic studies showed that miR-21 targets RhoB, as revealed by a decrease in RhoB expression and activity in miR-21 overexpressing cells. RhoB silencing impairs endothelial cell migration and tubulogenesis, thus providing a possible mechanism for miR-21 to inhibit angiogenesis. Finally, the therapeutic potential of miR-21 as an angiogenesis inhibitor was demonstrated in vivo in a mouse model of choroidal neovascularization.Conclusions/SignificanceOur results identify miR-21 as a new angiogenesis inhibitor and suggest that inhibition of cell migration and tubulogenesis is mediated through repression of RhoB.

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The interaction between tumor cells and their microenvironment is an essential aspect of tumor development. Therefore, understanding how this microenvironment communicates with tumor cells is crucial for the development of new anti-cancer therapies. MicroRNAs (miRNAs) are small non-coding RNAs that inhibit gene expression. They are secreted into the extracellular medium in vesicles called exosomes, which allow communication between cells via the transfer of their cargo. Consequently, we hypothesized that circulating endothelial miRNAs could be transferred to tumor cells and modify their phenotype. Using exogenous miRNA, we demonstrated that endothelial cells can transfer miRNA to tumor cells via exosomes. Using miRNA profiling, we identified miR-503, which exhibited downregulated levels in exosomes released from endothelial cells cultured under tumoral conditions. The modulation of miR-503 in breast cancer cells altered their proliferative and invasive capacities. We then identified two targets of miR-503, CCND2 and CCND3. Moreover, we measured increased plasmatic miR-503 in breast cancer patients after neoadjuvant chemotherapy, which could be partly due to increased miRNA secretion by endothelial cells. Taken together, our data are the first to reveal the involvement of the endothelium in the modulation of tumor development via the secretion of circulating miR-503 in response to chemotherapy treatment.

Circulating microRNAs (miRNAs) are increasingly recognized as powerful biomarkers in several pathologies, including breast cancer. Here, their plasmatic levels were measured to be used as an alternative screening procedure to mammography for breast cancer diagnosis.A plasma miRNA profile was determined by RT-qPCR in a cohort of 378 women. A diagnostic model was designed based on the expression of 8 miRNAs measured first in a profiling cohort composed of 41 primary breast cancers and 45 controls, and further validated in diverse cohorts composed of 108 primary breast cancers, 88 controls, 35 breast cancers in remission, 31 metastatic breast cancers and 30 gynecologic tumors.A receiver operating characteristic curve derived from the 8-miRNA random forest based diagnostic tool exhibited an area under the curve of 0.81. The accuracy of the diagnostic tool remained unchanged considering age and tumor stage. The miRNA signature correctly identified patients with metastatic breast cancer. The use of the classification model on cohorts of patients with breast cancers in remission and with gynecologic cancers yielded prediction distributions similar to that of the control group.Using a multivariate supervised learning method and a set of 8 circulating miRNAs, we designed an accurate, minimally invasive screening tool for breast cancer.