Cardiovascular diseases (CVD) represent the leading cause of morbidity and mortality globally. The emerging role of extracellular vesicles (EVs) in intercellular communication has stimulated renewed interest in exploring the potential application of EVs as tools for diagnosis, prognosis, and therapy in CVD. The ubiquitous nature of EVs in biological fluids presents a technological advantage compared to current diagnostic tools by virtue of their notable stability. EV contents, such as proteins and microRNAs, represent specific signatures of cellular activation or injury. This feature positions EVs as an alternative source of biomarkers. Furthermore, their intrinsic activity and immunomodulatory properties offer EVs unique opportunities to act as therapeutic agents per se or to serve as drug delivery carriers by acting as miniaturized vehicles incorporating bioactive molecules. In this article, we aim to review the recent advances and applications of EV-based biomarkers and therapeutics. In addition, the potential of EVs as a drug delivery and theranostic platform for CVD will also be discussed.

Arabidopsis HSI2 (HIGH-LEVEL EXPRESSION OF SUGAR-INDUCIBLE GENE 2) which carries a EAR (ERF-associated amphiphilic repression) motif acts as a repressor of seed maturation genes and lipid biosynthesis, whereas MEDIATOR (MED) is a conserved multiprotein complex linking DNA-bound transcription factors to RNA polymerase II transcription machinery. How HSI2 executes its repressive function through MED is hitherto unknown. Here, we show that HSI2 and its homolog, HSI2-lik (HSL1), are able to form homo- and heterocomplexes. Both factors bind to the TRAP240 domain of MED13, a subunit of the MED CDK8 module. Mutant alleles of the med13 mutant show elevated seed maturation gene expression and increased lipid accumulation in cotyledons; in contrast, HSI2- or MED13-overexpressing plants display the opposite phenotypes. The overexpression phenotypes of HSI2 and MED13 are abolished in med13 and hsi2 hsl1, respectively, indicating that HSI2 and MED13 together are required for these functions. The HSI2 C-terminal region interacts with HDA6, whose overexpression also reduces seed maturation gene expression and lipid accumulation. Moreover, HSI2, MED13 and HDA6 bind to the proximal promoter and 5′-coding regions of seed maturation genes. Taken together, our results suggest that HSI2 recruits MED13 and HDA6 to suppress directly a subset of seed maturation genes post-germination.

Regeneration of injured human heart muscle is limited and an unmet clinical need. There are no methods for the reproducible generation of clinical-quality stem cell-derived cardiovascular progenitors (CVPs). We identified laminin-221 (LN-221) as the most likely expressed cardiac laminin. We produced it as human recombinant protein and showed that LN-221 promotes differentiation of pluripotent human embryonic stem cells (hESCs) toward cardiomyocyte lineage and downregulates pluripotency and teratoma-associated genes. We developed a chemically defined, xeno-free laminin-based differentiation protocol to generate CVPs. We show high reproducibility of the differentiation protocol using time-course bulk RNA sequencing developed from different hESC lines. Single-cell RNA sequencing of CVPs derived from hESC lines supported reproducibility and identified three main progenitor subpopulations. These CVPs were transplanted into myocardial infarction mice, where heart function was measured by echocardiogram and human heart muscle bundle formation was identified histologically. This method may provide clinical-quality cells for use in regenerative cardiology.

Aims: The Toll-like receptor 7 (TLR7) is an intracellular innate immune receptor activated by nucleic acids shed from dying cells leading to activation of the innate immune system. Since innate immune system activation is involved in the response to myocardial infarction (MI), this study aims to identify if TLR7 is involved in post-MI ischaemic injury and adverse remodelling after MI.Methods and results: TLR7 involvement in MI was investigated in human tissue from patients with ischaemic heart failure, as well as in a mouse model of permanent left anterior descending artery occlusion in C57BL/6J wild type and TLR7 deficient (TLR7−/−) mice. TLR7 expression was up-regulated in human and mouse ischaemic myocardium after MI. Compared to wild type mice, TLR7−/− mice had less acute cardiac rupture associated with blunted activation of matrix metalloproteinase 2, increased expression of tissue inhibitor of metalloproteinase 1, recruitment of more myofibroblasts, and the formation of a myocardial scar with higher collagen fibre density. Furthermore, inflammatory cell influx and inflammatory cytokine expression post-MI were reduced in the TLR7−/− heart. During a 28-day follow-up after MI, TLR7 deficiency resulted in less chronic adverse left ventricular remodelling and better cardiac function. Bone marrow (BM) transplantation experiments showed that TLR7 deficiency in BM-derived cells preserved cardiac function after MI.Conclusions: In acute MI, TLR7 mediates the response to acute cardiac injury and chronic remodelling probably via modulation of post-MI scar formation and BM-derived inflammatory infiltration of the myocardium.

Background: L-type Ca _V 1.2 channels play crucial roles in the regulation of blood pressure. Galectin-1 (Gal-1) has been reported to bind to the I-II loop of Ca _V 1.2 channels to reduce their current density. However, the mechanistic understanding for the downregulation of Ca _V 1.2 channels by Gal-1 and whether Gal-1 plays a direct role in blood pressure regulation remain unclear. Methods: In vitro experiments involving coimmunoprecipitation, Western blot, patch-clamp recordings, immunohistochemistry, and pressure myography were used to evaluate the molecular mechanisms by which Gal-1 downregulates Ca _V 1.2 channel in transfected, human embryonic kidney 293 cells, smooth muscle cells, arteries from Lgasl1 ^−/− mice, rat, and human patients. In vivo experiments involving the delivery of Tat-e9c peptide and AAV5-Gal-1 into rats were performed to investigate the effect of targeting Ca _V 1.2-Gal-1 interaction on blood pressure monitored by tail-cuff or telemetry methods. Results: Our study reveals that Gal-1 is a key regulator for proteasomal degradation of Ca _V 1.2 channels. Gal-1 competed allosterically with the Ca _V β subunit for binding to the I-II loop of the Ca _V 1.2 channel. This competitive disruption of Ca _V β binding led to Ca _V 1.2 degradation by exposing the channels to polyubiquitination. It is notable that we demonstrated that the inverse relationship of reduced Gal-1 and increased Ca _V 1.2 protein levels in arteries was associated with hypertension in hypertensive rats and patients, and Gal-1 deficiency induces higher blood pressure in mice because of the upregulated Ca _V 1.2 protein level in arteries. To directly regulate blood pressure by targeting the Ca _V 1.2-Gal-1 interaction, we administered Tat-e9c, a peptide that competed for binding of Gal-1 by a miniosmotic pump, and this specific disruption of Ca _V 1.2-Gal-1 coupling increased smooth muscle Ca _V 1.2 currents, induced larger arterial contraction, and caused hypertension in rats. In contrasting experiments, overexpression of Gal-1 in smooth muscle by a single bolus of AAV5-Gal-1 significantly reduced blood pressure in spontaneously hypertensive rats. Conclusions: We have defined molecularly that Gal-1 promotes Ca _V 1.2 degradation by replacing Ca _V β and thereby exposing specific lysines for polyubiquitination and by masking I-II loop endoplasmic reticulum export signals. This mechanistic understanding provided the basis for targeting Ca _V 1.2-Gal-1 interaction to demonstrate clearly the modulatory role that Gal-1 plays in regulating blood pressure, and offering a potential approach for therapeutic management of hypertension.