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Immune cells have an important role in the tumor-microenvironment. Macrophages may tune the immune response toward inflammatory or tolerance pathways. Tumor-associated macrophages (TAM) have a string of immunosuppressive functions and they are considered a therapeutic target in cancer. This study aimed to analyze the effects of trabectedin, an antitumor agent, on the tumor-microenvironment through the characterization of the electrophysiological and molecular phenotype of macrophages. Experiments were performed using the whole-cell configuration of the patch-clamp technique in resident peritoneal mouse macrophages. Trabectedin does not directly interact with KV1.5 and KV1.3 channels, but their treatment (16 h) with sub-cytotoxic concentrations of trabectedin increased their KV current due to an upregulation of KV1.3 channels. In vitro generated TAM (TAMiv) exhibited an M2-like phenotype. TAMiv generated a small KV current and express high levels of M2 markers. K+ current from TAMs isolated from tumors generated in mice is a mixture of KV and KCa, and in TAM isolated from tumors generated in trabectedin-treated mice, the current is mostly driven by KCa. We conclude that the antitumor capacity of trabectedin is not only due to its effects on tumor cells, but also to the modulation of the tumor microenvironment, due, at least in part, to the modulation of the expression of different macrophage ion channels.

[Background]: Resolution of inflammation is orchestrated by specialized proresolving lipid mediators (SPMs), and this would be impaired in some cardiovascular diseases. Among SPMs, resolvins (Rv) have beneficial effects in cardiovascular pathologies, but little is known about their effect on cardiovascular damage in hypertension., [Methods:]: Aorta, small mesenteric arteries, heart, and peritoneal macrophages were taken from C57BL/6J mice, infused or not with angiotensin II (AngII; 1.44 mg/kg/day, 14 days) in presence or absence of resolvin D2 (RvD2) (100 ng/mice, every second day) starting 1 day before or 7 days after AngII infusion., [Results]: Enzymes and receptors involved in SPMs biosynthesis and signaling were increased in aorta or heart from AngII-infused mice. We also observed a differential regulation of SPMs in heart from these mice. Preventive treatment with RvD2 partially avoided AngII-induced hypertension and protected the heart and large and small vessels against functional and structural alterations induced by AngII. RvD2 increased the availability of vasoprotective factors, modified SPMs profile, decreased cardiovascular fibrosis, and increased the infiltration of pro-resolving macrophages. When administered in hypertensive animals with established cardiovascular damage, RvD2 partially improved cardiovascular function and structure, decreased fibrosis, reduced the infiltration of neutrophils, and shifted macrophage phenotype toward a pro-resolving phenotype., [Conclusions]: There is a disbalance between proinflammatory and resolution mediators in hypertension. RvD2 protects cardiovascular function and structure when administered before and after the development of hypertension by modulating vascular factors, fibrosis and inflammation. Activating resolution mechanisms by treatment with RvD2 may represent a novel therapeutic strategy for the treatment of hypertensive cardiovascular disease.

AIMS: Interferon-stimulated gene 15 (ISG15) encodes a ubiquitin-like protein that induces a reversible post-translational modification (ISGylation) and can also be secreted as a free form. ISG15 plays an essential role as host-defence response to microbial infection; however, its contribution to vascular damage associated with hypertension is unknown. METHODS AND RESULTS: Bioinformatics identified ISG15 as a mediator of hypertension-associated vascular damage. ISG15 expression positively correlated with systolic and diastolic blood pressure and carotid intima-media thickness in human peripheral blood mononuclear cells. Consistently, Isg15 expression was enhanced in aorta from hypertension models and in angiotensin II (AngII)-treated vascular cells and macrophages. Proteomics revealed differential expression of proteins implicated in cardiovascular function, extracellular matrix and remodelling, and vascular redox state in aorta from AngII-infused ISG15-/- mice. Moreover, ISG15-/- mice were protected against AngII-induced hypertension, vascular stiffness, elastin remodelling, endothelial dysfunction, and expression of inflammatory and oxidative stress markers. Conversely, mice with excessive ISGylation (USP18C61A) show enhanced AngII-induced hypertension, vascular fibrosis, inflammation and reactive oxygen species (ROS) generation along with elastin breaks, aortic dilation, and rupture. Accordingly, human and murine abdominal aortic aneurysms showed augmented ISG15 expression. Mechanistically, ISG15 induces vascular ROS production, while antioxidant treatment prevented ISG15-induced endothelial dysfunction and vascular remodelling. CONCLUSION: ISG15 is a novel mediator of vascular damage in hypertension through oxidative stress and inflammation.

In recent years, gut dysbiosis has been related to some peripheral vascular alterations linked to hypertension. In this work, we explore whether gut dysbiosis is related to vascular innervation dysfunction and altered nitric oxide (NO) production in the superior mesenteric artery, one of the main vascular beds involved in peripheral vascular resistance. For this purpose, we used spontaneously hypertensive rats, either treated or not with the commercial synbiotic formulation Prodefen® (108 colony forming units/day, 4 weeks). Prodefen® diminished systolic blood pressure and serum endotoxin, as well as the vasoconstriction elicited by electrical field stimulation (EFS), and enhanced acetic and butyric acid in fecal samples, and the vasodilation induced by the exogenous NO donor DEA-NO. Unspecific nitric oxide synthase (NOS) inhibitor L-NAME increased EFS-induced vasoconstriction more markedly in rats supplemented with Prodefen®. Both neuronal NO release and neuronal NOS activity were enhanced by Prodefen®, through a hyperactivation of protein kinase (PK)A, PKC and phosphatidylinositol 3 kinase-AKT signaling pathways. The superoxide anion scavenger tempol increased both NO release and DEA-NO vasodilation only in control animals. Prodefen® caused an increase in both nuclear erythroid related factor 2 and superoxide dismutase activities, consequently reducing both superoxide anion and peroxynitrite releases. In summary, Prodefen® could be an interesting non-pharmacological approach to ameliorate hypertension.

[Background and Purpose]: KV1.3 channels are expressed in vascular smooth muscle cells (VSMCs), where they contribute to proliferation rather than contraction and participate in vascular remodelling. KV1.3 channels are also expressed in macrophages, where they assemble with KV1.5 channels (KV1.3/KV1.5), whose activation generates a KV current. In macrophages, the KV1.3/KV1.5 ratio is increased by classical activation (M1). Whether these channels are involved in angiotensin II (AngII)-induced vascular remodelling, and whether they can modulate the macrophage phenotype in hypertension, remains unknown. We characterized the role of KV1.3 channels in vascular damage in hypertension., [Experimental Approach]: We used AngII-infused mice treated with two selective KV1.3 channel inhibitors (HsTX[R14A] and [EWSS]ShK). Vascular function and structure were measured using wire and pressure myography, respectively. VSMC and macrophage electrophysiology were studied using the patch-clamp technique; gene expression was analysed using RT-PCR., [Key Results]: AngII increased KV1.3 channel expression in mice aorta and peritoneal macrophages which was abolished by HsTX[R14A] treatment. KV1.3 inhibition did not prevent hypertension, vascular remodelling, or stiffness but corrected AngII-induced macrophage infiltration and endothelial dysfunction in the small mesenteric arteries and/or aorta, via a mechanism independent of electrophysiological changes in VSMCs. AngII modified the electrophysiological properties of peritoneal macrophages, indicating an M1-like activated state, with enhanced expression of proinflammatory cytokines that induced endothelial dysfunction. These effects were prevented by KV1.3 blockade., [Conclusions and Implications]: We unravelled a new role for KV1.3 channels in the macrophage-dependent endothelial dysfunction induced by AngII in mice which might be due to modulation of macrophage phenotype.

Immune cells have an important role in the tumor-microenvironment. Macrophages may tune the immune response toward inflammatory or tolerance pathways. Tumor associated macrophages (TAM) have immunosuppressive functions and they are considered a therapeutic target in cancer. The aim of this study was to evaluate the effects of trabectedin, a new class of antitumor agent, on the tumor-microenvironment through the study of electrophysiological and molecular phenotype of macrophages. Experiments were performed using the whole-cell configuration of the patch-clamp technique in resident peritoneal mouse macrophages under different types of polarization. Trabectedin decreased macrophage viability and increased ROS production. Trabectedin does not directly interact with KV1.5 and KV1.3 channels, but treatment (16 h) of macrophages with sub-cytotoxic concentrations (0.1-5 nM) increased their KV current in a concentration-dependent manner due to an upregulation of KV1.3 channels. In vitro generated TAM (TAMiv), by a co-culture of ID8 cells and macrophages, exhibited a M2 phenotype. TAMiv generated a small KV current, similarly to M2 polarized macrophages, and expressed high levels of M2 markers. In this study, we demonstrated that TAMiv polarization could be re-educated by using sub-cytotoxic concentration of trabectedin. TAMiv treated with sub-cytotoxic concentration of trabectedin exhibited an upregulation of KV1.3 channels and their M2 phenotype changed towards M1 pro-inflammatory one.

Macrophages play an important role in the inflammatory response, acting as antigen-presenting cells and modifying the cytokine milieu and the intensity of T-cell signaling. The electrophysiological properties of macrophages depend on their state of functional activation. Trabectedin induces rapid apoptosis exclusively in mononuclear phagocytes and this effect contributes directly to its antitumor activity. The aim of this study was to evaluate the effects of trabectedin on KV and Kir channels in resident peritoneal and bone marrow-derived macrophages (BMDM) under both short- and long-term incubation with the drug. Experiments were performed using the whole-cell configuration of the patchclamp technique. Following exposure (ca. 10 min) of peritoneal macrophages or BMDM to 100 nM trabectedin neither KV nor Kir were modified. The electrophysiological effects of prolonged treatment with trabectedin were studied after 16 h of incubation with the drug. Under these conditions, trabectedin produced a concentration-dependent effect that was qualitatively similar to the response observed after LPS challenge. Moreover, the increase in KV observed appeared in parallel with a use-dependent decline, typical of macrophages stimulated with LPS. Similarly, the degree of inactivation of the current was greater and faster at higher trabectedin concentrations. All these results suggest that: 1) Trabectedin does not interact with Kir or KV channel. 2) Trabectedin acts by re-educating mouse resting peritoneal macrophages into M1-subtype.