Transcription factor TFEB is thought to control cellular functions—including in the vascular bed—primarily via regulation of lysosomal biogenesis and autophagic flux. Here, we report that TFEB also orchestrates a non‐canonical program that controls the cell cycle/VEGFR2 pathway in the developing vasculature. In endothelial cells, TFEB depletion halts proliferation at the G1‐S transition by inhibiting the CDK4/Rb pathway. TFEB‐deficient cells attempt to compensate for this limitation by increasing VEGFR2 levels at the plasma membrane via microRNA‐mediated mechanisms and controlled membrane trafficking. TFEB stimulates expression of the miR‐15a/16‐1 cluster, which limits VEGFR2 transcript stability and negatively modulates expression of MYO1C, a regulator of VEGFR2 trafficking to the cell surface. Altered levels of miR‐15a/16‐1 and MYO1C in TFEB‐depleted cells cause increased expression of plasma membrane VEGFR2, but in a manner associated with low signaling strength. An endothelium‐specific Tfeb‐knockout mouse model displays defects in fetal and newborn mouse vasculature caused by reduced endothelial proliferation and by anomalous function of the VEGFR2 pathway. These previously unrecognized functions of TFEB expand its role beyond regulation of the autophagic pathway in the vascular system.

Central obesity shows impaired platelet responses to the antiaggregating effects of nitric oxide (NO), prostacyclin, and their effectors-guanosine 3′,5′-cyclic monophosphate (cGMP) and adenosine 3′,5′-cyclic monophosphate (cAMP). The influence of weight loss on these alterations is not known. To evaluate whether a diet-induced body-weight reduction restores platelet sensitivity to the physiological antiaggregating agents and reduces platelet activation in subjects affected by central obesity, we studied 20 centrally obese subjects before and after a 6-month diet intervention aiming at reducing body weight by 10%, by measuring (i) insulin sensitivity (homeostasis model assessment of insulin resistance (HOMA IR )); (ii) plasma lipids; (iii) circulating markers of inflammation of adipose tissue and endothelial dysfunction, and of platelet activation (i.e., soluble CD-40 ligand (sCD-40L) and soluble P-selectin (sP-selectin)); (iv) ability of the NO donor sodium nitroprusside (SNP), the prostacyclin analog Iloprost and the cyclic nucleotide analogs 8-bromoguanosine 3′,5′-cyclic monophosphate (8-Br-cGMP) and 8-bromoadenosine 3′,5′-cyclic monophosphate (8-Br-cAMP) to reduce platelet aggregation in response to adenosine-5-diphosphate (ADP); and (v) ability of SNP and Iloprost to increase cGMP and cAMP. The 10 subjects who reached the body-weight target showed significant reductions of insulin resistance, adipose tissue, endothelial dysfunction, and platelet activation, and a significant increase of the ability of SNP, Iloprost, 8-Br-cGMP, and 8-Br-cAMP to reduce ADP-induced platelet aggregation and of the ability of SNP and Iloprost to increase cyclic nucleotide concentrations. No change was observed in the 10 subjects who did not reach the body-weight target. Changes of platelet function correlated with changes of HOMA IR . Thus, in central obesity, diet-induced weight loss reduces platelet activation and restores the sensitivity to the physiological antiaggregating agents, with a correlation with improvements in insulin sensitivity.

Visceral obesity is a relevant pathological condition closely associated with high risk of atherosclerotic vascular disease including myocardial infarction and stroke. The increased vascular risk is related also to peculiar dysfunction in the endocrine activity of adipose tissue responsible of vascular impairment (including endothelial dysfunction), prothrombotic tendency, and low-grade chronic inflammation. In particular, increased synthesis and release of different cytokines, including interleukins and tumor necrosis factor-α (TNF-α), and adipokines—such as leptin—have been reported as associated with future cardiovascular events. Since vascular cell dysfunction plays a major role in the atherothrombotic complications in central obesity, this paper aims at focusing, in particular, on the relationship between platelets and vascular smooth muscle cells, and the impaired secretory pattern of adipose tissue.

Platelet resistance to the antiaggregating effects of prostacyclin and NO in obesity is attributable to impairment of cyclic nucleotide synthesis and action. As cyclic nucleotides are the main effectors of platelet antiaggregation, the resistance to them can account for platelet hyperactivity in obesity.

In VSMCs from humans and insulin-sensitive Zucker fa/+rats: (i) insulin increases VEGF protein expression and secretion via both PI3-K and MAPK; (ii) the insulin effects on VEGF are mediated by nitric oxide. The insulin action on both nitric oxide and VEGF is impaired in VSMCs from Zucker fa/fa rats, an animal model of metabolic and vascular insulin-resistance.

Transcription factor EB (TFEB) in stressed cells activates autophagic flux and lysosome biogenesis. Besides this canonical pathway, emerging findings indicate that TFEB regulates cell cycle, metabolism and inflammation. This review summarizes the role of TFEB in cancer onset and progression and advances multiple roles as an oncogene and regulator of the crosstalk circuits between cancer cells and tumor microenvironment (TME).

Some in vivo and ex vivo studies demonstrated a resistance to the vasodilating effects of nitric oxide (NO) in insulin-resistant states and, in particular, obese Zucker rats (OZR). To evaluate the biochemical basis of this phenomenon, we aimed to identify defects of the NO/cGMP/cGMP-dependent protein kinase (PKG) pathway in cultured vascular smooth muscle cells (VSMCs) from OZR and lean Zucker rats (LZR) by measuring: 1) NO donor ability to increase cGMP in the absence and presence of inhibitors of soluble guanylate cyclase (sGC) and phosphodiesterases (PDEs); 2) NO and cGMP ability to induce, via PKG, vasodilator-stimulated phosphoprotein (VASP) phosphorylation at serine 239 and PDE5 activity; 3) protein expression of sGC, PKG, total VASP, and PDE5; 4) superoxide anion concentrations and ability of antioxidants (superoxide dismutase+catalase and amifostine) to influence the NO/cGMP/PKG pathway activation; and 5) hydrogen peroxide influence on PDE5 activity and VASP phosphorylation. VSMCs from OZR vs. LZR showed: 1) baseline cGMP concentrations higher, at least in part owing to reduced catabolism by PDEs; 2) impairment of NO donor ability to increase cGMP, even in the presence of PDE inhibitors, suggesting a defect in the NO-induced sGC activation; 3) reduction of NO and cGMP ability to activate PKG, indicated by the impaired ability to phosphorylate VASP at serine 239 and to increase PDE5 activity via PKG; 4) similar baseline protein expression of sGC, PKG, total VASP, and PDE5; and 5) higher levels of superoxide anion. Antioxidants partially prevented the defects of the NO/cGMP/PKG pathway observed in VSMCs from OZR, which were reproduced by hydrogen peroxide in VSMCs from LZR, suggesting the pivotal role of oxidative stress.

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