P2Y(4) nucleotide receptor: a novel actor in post-natal cardiac development.

Communication between endothelial cells and cardiomyocytes is critical for cardiac development and regeneration. However the mechanisms involved in these endothelial-cardiomyocyte interactions remain poorly understood. Nucleotides are released within the heart, especially under ischemia or pressure overload. The function of P2Y nucleotide receptors in cardiac development has never been investigated. Here we show that adult P2Y(4)-null mice display microcardia. P2Y(4) nucleotide receptor is expressed in cardiac endothelial cells but not in cardiomyocytes. Loss of P2Y(4) in cardiac endothelial cells strongly inhibits their growth, migration and PDGF-B secretion in response to UTP. Proliferation of microvessels and cardiomyocytes is reduced in P2Y(4)-null hearts early after birth, resulting in reduced heart growth. Our study uncovers mouse P2Y(4) receptor as an essential regulator of cardiac endothelial cell function, and illustrates the involvement of endothelial-cardiomyocyte interactions in post-natal heart development. We also detected P2Y(4) expression in human cardiac microvessels. P2Y(4) receptor could constitute a therapeutic target to regulate cardiac remodelling and post-ischemic revascularisation.

Targeting Tumor Angiogenesis with the Selective VEGFR-3 Inhibitor EVT801 in Combination with Cancer Immunotherapy.

The receptor tyrosine kinase VEGFR-3 plays a crucial role in cancer-induced angiogenesis and lymphangiogenesis, promoting tumor development and metastasis. Here, we report the novel VEGFR-3 inhibitor EVT801 that presents a more selective and less toxic profile than two major inhibitors of VEGFRs (i.e., sorafenib and pazopanib). As monotherapy, EVT801 showed a potent antitumor effect in VEGFR-3-positive tumors, and in tumors with VEGFR-3-positive microenvironments. EVT801 suppressed VEGF-C-induced human endothelial cell proliferation in vitro and tumor (lymph)angiogenesis in different tumor mouse models. In addition to reduced tumor growth, EVT801 decreased tumor hypoxia, favored sustained tumor blood vessel homogenization (i.e., leaving fewer and overall larger vessels), and reduced important immunosuppressive cytokines (CCL4, CCL5) and myeloid-derived suppressor cells (MDSC) in circulation. Furthermore, in carcinoma mouse models, the combination of EVT801 with immune checkpoint therapy (ICT) yielded superior outcomes to either single treatment. Moreover, tumor growth inhibition was inversely correlated with levels of CCL4, CCL5, and MDSCs after treatment with EVT801, either alone or combined with ICT. Taken together, EVT801 represents a promising anti(lymph)angiogenic drug for improving ICT response rates in patients with VEGFR-3 positive tumors. Significance: The VEGFR-3 inhibitor EVT801 demonstrates superior selectivity and toxicity profile than other VEGFR-3 tyrosine kinase inhibitors. EVT801 showed potent antitumor effects in VEGFR-3-positive tumors, and tumors with VEGFR-3-positive microenvironments through blood vessel homogenization, and reduction of tumor hypoxia and limited immunosuppression. EVT801 increases immune checkpoint inhibitors' antitumor effects.

Rimonabant, a selective cannabinoid CB1 receptor antagonist, inhibits atherosclerosis in LDL receptor-deficient mice.

OBJECTIVE: The objective of this study was to determine whether the potent selective cannabinoid receptor-1 antagonist rimonabant has antiatherosclerotic properties. METHODS AND RESULTS: Rimonabant (50 mg/kg/d in the diet) significantly reduced food intake (from 3.35+/-.04 to 2.80+/-0.03 g/d), weight gain (from 14.6+/-0.7 g to -0.6+/-0.3 g), serum total cholesterol (from 8.39+/-0.54 to 5.32+/-0.18 g/L), and atherosclerotic lesion development in the aorta (from 1.7+/-0.22 to 0.21+/-0.037 mm(2)) and aortic sinus (from 101,000+/-7800 to 27,000+/-2900 microm(2)) of LDLR(-/-) mice fed a Western-type diet for 3 months. Rimonabant also reduced plasma levels of the proinflammatory cytokines MCP-1 and IL12 by 85% (P<0.05) and 76% (P<0.05), respectively. Pair-fed animals had reduced weight gain (6.2+/-0.6 g gain), but developed atherosclerotic lesions which were as large as those of untreated animals, showing that the antiatherosclerotic effect of rimonabant is not related to reduced food intake. Interestingly, rimonabant at a lower dose (30 mg/kg/d in the diet) reduced atherosclerosis development in the aortic sinus (from 121,000+/-20,000 to 62,000+/-11,000 microm(2), 49% reduction, P<0.05), without affecting serum total cholesterol (7.8+/-0.7 g/L versus 8.1+/-1.3 g/L in the control group). Rimonabant decreased lipopolysaccharide (LPS)- and IL1beta-induced proinflammatory gene expression in mouse peritoneal macrophages in vitro as well as thioglycollate-induced recruitment of macrophages in vivo (10 mg/kg, p.o. bolus). CONCLUSIONS: These results show that rimonabant has antiatherosclerotic effects in LDLR(-/-) mice. These effects are partly unrelated to serum cholesterol modulation and could be related to an antiinflammatory effect.

Effect of SR58611A, a potent beta-3 adrenoceptor agonist, on cutaneous wound healing in diabetic and obese mice.

In diabetic patients, impairment of wound healing is a serious problem which represents a significant health burden. The effect of a highly selective beta-3 adrenoceptor agonist, SR58611A, on wound healing was assessed in animal models of type II diabetes. In db/db diabetic mice, a daily oral treatment with SR58611A (1, 3 and 10 mg/kg/day for two weeks) significantly reduced hyperglycaemia from 3 mg/kg/day onwards. The compound also normalized wound healing, starting from the lowest dose tested (1 mg/kg/day). SR58611A did not affect wound healing of control (lean) mice. An oral anti-diabetic agent, devoid of affinity for beta-3 adrenoceptors, troglitazone (130 mg/kg/day p.o.), normalized glycaemia but did not improve wound healing in db/db mice. Local application of SR58611A (200 microg/day in db/db mice) did not affect wound healing. SR58611A also normalized glucose levels in ob/ob mice, but only slightly improved wound healing in this strain. Moreover, in 17-week old db/db mice (i.e. severely insulin resistant) and in streptozotocin-induced diabetic mice, SR58611A slightly decreased hyperglycaemia and did not affect wound healing. In conclusion, SR58611A improves wound healing in animal models of non-insulin-dependent diabetes. This effect is not related to its effect on glucose levels, but probably implicates systemic effects of the compound.

A new synthetic FGF receptor antagonist inhibits arteriosclerosis in a mouse vein graft model and atherosclerosis in apolipoprotein E-deficient mice.

OBJECTIVE: The role of fibroblast growth factors (FGFs) in the development of vascular diseases remains incompletely understood. The objective of this study was to examine the effects of a new small-molecule multi-FGF receptor blocker with allosteric properties, SSR128129E, on neointimal proliferation after a vein graft procedure in mice and on the development of atherosclerosis in atherosclerosis-prone apolipoprotein E (apoE)-deficient mice. METHODS AND RESULTS: Vein grafts were performed in 3 month-old male C57BL6 mice. Segments of the vena cava were interposed at the level of the carotid artery. In SSR128129E (50 mg/kg/d)-treated animals, a dramatic decrease in neointimal proliferation was observed 2 and 8 weeks after the graft (72.5%, p<0.01, and 47.8%, p<0.05, respectively). Four-week old male apoE-deficient mice were treated with SSR128129E (50 mg/kg/d) for 3 and 5 months in comparison with a control group. SSR128129E treatment resulted in a reduction of lesion size in the aortic sinus (16.4% (ns) at 3 months and 42.9% (p<0.01) at 5 months, without any change in serum lipids. SSR128129 significantly reduced FGFR2 mRNA levels in the aortic sinus (p<0.05, n=5-6), but did not affect the mRNA expression levels of other FGF receptors or ligands. CONCLUSION: These studies indicate that FGFs have an important role in the development of vascular diseases like atherosclerosis and graft arteriosclerosis. These data suggest that inhibition of FGF receptors by compounds like SSR128129E might be useful as a new therapeutic approach for these vascular pathologies.

Inhibition of tumor angiogenesis and growth by a small-molecule multi-FGF receptor blocker with allosteric properties.

Receptor tyrosine kinases (RTK) are targets for anticancer drug development. To date, only RTK inhibitors that block orthosteric binding of ligands and substrates have been developed. Here, we report the pharmacologic characterization of the chemical SSR128129E (SSR), which inhibits fibroblast growth factor receptor (FGFR) signaling by binding to the extracellular FGFR domain without affecting orthosteric FGF binding. SSR exhibits allosteric properties, including probe dependence, signaling bias, and ceiling effects. Inhibition by SSR is highly conserved throughout the animal kingdom. Oral delivery of SSR inhibits arthritis and tumors that are relatively refractory to anti-vascular endothelial growth factor receptor-2 antibodies. Thus, orally-active extracellularly acting small-molecule modulators of RTKs with allosteric properties can be developed and may offer opportunities to improve anticancer treatment.