Small-molecule inhibitors of signal transducer and activator of transcription 3 protect against angiotensin II-induced vascular dysfunction and hypertension

STAT protein family and cardiovascular diseases: overview of pathological mechanisms and therapeutic implications

Globally, cardiovascular diseases (CVD) are one of the significant causes of death and are considered a major concern of human society. One of the most crucial objectives of scientists is to reveal the mechanisms associated with the pathogenesis of CVD, which has attracted the attention of many scientists. Accumulating evidence showed that the signal transducer and activator of transcription (STAT) signaling pathway is involved in various physiological and pathological processes. According to research on the molecular mechanisms of CVDs, the STAT family of proteins is one of the most crucial players in these diseases. Numerous studies have demonstrated the undeniable relevance of STAT family proteins in various CVDs. The aim of this review is to shed light on how STAT signaling pathways are related to CVD and the potential for using these signaling pathways as therapeutic targets.

Proliferation, migration and phenotypic transformation of VSMC induced via Hcy related to up-expression of WWP2 and p-STAT3

To provide a theoretical basis for the prevention and treatment of atherosclerosis (AS), the current study aimed to investigate the mechanism underlying the effect of homocysteine (Hcy) on regulating the proliferation, migration and phenotypic transformation of vascular smooth muscle cells (VSMC) via sirtuin-1 (SIRT1)/signal transducer and activator of transcription 3 (STAT3) through Nedd4-like E3 ubiquitin-protein ligase WWP2 (WWP2). Here, Based on the establishment of ApoE-/- mouse models of high Hcy As and the model of Hcy stimulation of VSMC in vitro to observe the interaction between WWP2 and STAT3 and its effect on the proliferation, migration, and phenotypic transformation of Hcy-induced VSMC, which has not been previously reported. This study revealed that WWP2 could promote the proliferation, migration, and phenotype switch of Hcy-induced VSMC by up-regulating the phosphorylation of SIRT1/STAT3 signaling. Furthermore, Hcy might up-regulate WWP2 expression by inhibiting histone H3K27me3 expression through up-regulated UTX. These data suggest that WWP2 is a novel and important regulator of Hcy-induced VSMC proliferation, migration, and phenotypic transformation.

SENP1 Protects Against Pressure Overload‐Induced Cardiac Remodeling and Dysfunction Via Inhibiting STAT3 Signaling

Background

SENP1 (sentrin/small ubiquitin‐like modifier‐specific protease 1) has emerged as a significant modulator involved in the pathogenesis of a variety of human diseases, especially cancer. However, the regulatory roles of SENP1 in cardiovascular biology and diseases remain controversial. Our current study aims to clarify the function and regulation of SENP1 in pressure overload‐induced cardiac remodeling and dysfunction.

Methods and Results

We used a preclinical mouse model of transverse aortic constriction coupled with in vitro studies in neonatal rat cardiomyocytes to study the role of SENP1 in cardiac hypertrophy. Gene delivery system was used to knockdown or overexpress SENP1 in vivo. Here, we observed that SENP1 expression was significantly augmented in murine hearts following transverse aortic constriction as well as neonatal rat cardiomyocytes treated with phenylephrine or angiotensin II. Cardiac‐specific SENP1 knockdown markedly exacerbated transverse aortic constriction‐induced cardiac hypertrophy, systolic dysfunction, fibrotic response, and cellular apoptosis. In contrast, adenovirus‐mediated SENP1 overexpression in murine myocardium significantly attenuated cardiac remodeling and dysfunction following chronic pressure overload. Mechanistically, JAK2 (Janus kinase 2) and STAT3 (signal transducer and activator of transcription 3) acted as new interacting partners of SENP1 in this process. SENP1‐JAK2/STAT3 interaction suppressed STAT3 nuclear translocation and activation, ultimately inhibiting the transcription of prohypertrophic genes and the initiation of hypertrophic response. Furthermore, cardiomyocyte‐specific STAT3 knockout mice were generated to validate the underlying mechanisms, and the results showed that STAT3 ablation blunted the cardiac hypertrophy‐promoting effects of SENP1 deficiency. Additionally, pharmacological inhibition of SENP1 by Momordin Ic amplified cardiac remodeling post‐transverse aortic constriction.

Conclusions

Our study provided evidence that SENP1 protected against pressure overload‐induced cardiac remodeling and dysfunction via inhibiting STAT3 signaling. SENP1 supplementation might constitute a new promising treatment against cardiac hypertrophy. Notably, cardiovascular side effects should be seriously considered while applying systemic SENP1 blockers to suppress tumors.

COX/iNOS dependence for angiotensin-II-induced endothelial dysfunction

Vascular dysfunction induced by angiotensin-II can result from direct effects on vascular and inflammatory cells and indirect hemodynamic effects. Using isolated and functional cultured aortas, we aimed to identify the effects of angiotensin-II on cyclooxygenase (COX) and inducible nitric oxide synthase (iNOS) and evaluate their impact on vascular reactivity. Aortic rings from mice were incubated overnight in culture medium containing angiotensin-II (100 nmol/L) or vehicle to induce vascular disfunction. Vascular reactivity of cultured arteries was evaluated in a bath chamber. Immunofluorescence staining for COX-1 and COX-2 was performed. Nitric oxide (NO) formation was approached by the levels of nitrite, a NO end product, and using a fluorescent probe (DAF). Oxidative and nitrosative stress were determined by DHE fluorescence and nitrotyrosine staining, respectively. Arteries cultured with angiotensin-II showed impairment of endothelium-dependent relaxation, which was reversed by the AT₁ receptor antagonist. Inhibition of COX and iNOS restored vascular relaxation, suggesting a common pathway in which angiotensin-II triggers COX and iNOS, leading to vasoconstrictor receptors activation. Moreover, using selective antagonists, TP and EP were identified as the receptors involved in this response. Endothelium-dependent contractions of angiotensin-II-cultured aortas were blunted by ibuprofen, and increased COX-2 immunostaining was found in the arteries, indicating endothelium release of vasoconstrictor prostanoids. Angiotensin-II induced increased reactive oxygen species and NO production. An iNOS inhibitor prevented NO enhancement and nitrotyrosine accumulation in arteries stimulated with angiotensin-II. These results confirm that angiotensin-II causes vascular inflammation that culminates in endothelial dysfunction in an iNOS and COX codependent manner.

Theories and Molecular Basis of Vascular Aging: A Review of the Literature from VascAgeNet Group on Pathophysiological Mechanisms of Vascular Aging

Vascular aging, characterized by structural and functional alterations of the vascular wall, is a hallmark of aging and is tightly related to the development of cardiovascular mortality and age-associated vascular pathologies. Over the last years, extensive and ongoing research has highlighted several sophisticated molecular mechanisms that are involved in the pathophysiology of vascular aging. A more thorough understanding of these mechanisms could help to provide a new insight into the complex biology of this non-reversible vascular process and direct future interventions to improve longevity. In this review, we discuss the role of the most important molecular pathways involved in vascular ageing including oxidative stress, vascular inflammation, extracellular matrix metalloproteinases activity, epigenetic regulation, telomere shortening, senescence and autophagy.

Angiotensin II-induced endothelial dysfunction: Impact of sex, genetic background, and rho kinase

The renin-angiotensin system (RAS) contributes to vascular disease with multiple cardiovascular risk factors including hypertension. As a major effector within the RAS, angiotensin II (Ang II) activates diverse signaling mechanisms that affect vascular biology. Despite the impact of such vascular pathophysiology, our understanding of the effects of Ang II in relation to the function of endothelial cells is incomplete. Because genetic background and biological sex can be determinants of vascular disease, we performed studies examining the direct effects of Ang II using carotid arteries from male and female mice on two genetic backgrounds, C57BL/6J and FVB/NJ. Although FVB/NJ mice are much less susceptible to atherosclerosis than C57BL/6J, the effects of Ang II on endothelial cells in FVB/NJ are poorly defined. Overnight incubation of isolated arteries with Ang II (10 nmol/L), impaired endothelial function in both strains and sexes by approximately one-half (p < 0.05). To examine the potential mechanistic contribution of Rho kinase (ROCK), we treated arteries with SLX-2119, an inhibitor with high selectivity for ROCK2. In both male and female mice of both strains, SLX-2119 largely restored endothelial function to normal, compared to vessels treated with vehicle. Thus, Ang II-induced endothelial dysfunction was observed in both FVB/NJ and C57BL/6J mice. This effect was sex-independent. In all groups, effects of Ang II were reversed by inhibition of ROCK2 with SLX-2119. These studies provide the first evidence that ROCK2 may be a key contributor to Ang II-induced endothelial dysfunction in both sexes and in mouse strains that differ in relation to other major aspects of vascular disease.

Neuronal STAT3/HIF-1α/PTRF axis-mediated bioenergetic disturbance exacerbates cerebral ischemia-reperfusion injury via PLA2G4A

Ischemic stroke is an acute and severe neurological disease with high mortality and disability rates worldwide. Polymerase I and transcript release factor (PTRF) plays a pivotal role in regulating cellular senescence, glucose intolerance, lipid metabolism, and mitochondrial bioenergetics, but its mechanism, characteristics, and functions in neuronal cells following the cerebral ischemia-reperfusion (I/R) injury remain to be determined. Methods: Transcription factor motif analysis, chromatin immunoprecipitation (ChIP), luciferase and co-Immunoprecipitation (co-IP) assays were performed to investigate the mechanisms of PTRF in neuronal cells after I/R injury. Lentiviral-sgRNA against PTRF gene was introduced to HT22 cells, and adeno-associated virus (AAV) encoding a human synapsin (hSyn) promoter-driven construct was transduced a short hairpin RNA (shRNA) against PTRF mRNA in primary neuronal cells and the cortex of the cerebral I/R mice for investigating the role of PTRF in neuronal damage and PLA2G4A change induced by the cerebral I/R injury. Results: Here, we reported that neuronal PTRF was remarkably increased in the cerebral penumbra after I/R injury, and HIF-1α and STAT3 regulated the I/R-dependent expression of PTRF via binding to its promoter in neuronal cells. Moreover, overexpression of neuronal PTRF enhanced the activity and stability of PLA2G4A by decreasing its proteasome-mediated degradation pathway. Subsequently, PTRF promoted reprogramming of lipid metabolism and altered mitochondrial bioenergetics, which could lead to oxidative damage, involving autophagy, lipid peroxidation, and ferroptosis via PLA2G4A in neuronal cells. Furthermore, inhibition of neuronal PTRF/PLA2G4A-axis markedly reduced the neurological deficits, cerebral infarct volumes, and mortality rates in the mice following cerebral I/R injury. Conclusion: Our results thus identify that the STAT3/HIF-1α/PTRF-axis in neurons, aggravating cerebral I/R injury by regulating the activity and stability of PLA2G4A, might be a novel therapeutic target for ischemic stroke.

Endothelium function biomarkers and carotid intima-media thickness changes in relation to NOS3 (rs2070744) and GNB3 (rs5443) genes polymorphism in the essential arterial hypertension

Objective. The aim of the present study was to clarify the endothelial function biomarkers and carotid "intima media" thickness (IMT) changes in relation to GNB3 (rs5443) and NOS3 (rs2070744) genes polymorphism in the essential arterial hypertension (EAH). Methods. One-hundred EAH patients (48 - control) participated in the case-control study. Soluble vascular cell adhesion molecule (sVCAM-1), total NO metabolites (NO₂ ^-+NO₃ ^-), transcriptional activity of NOS3 gene, endothelium-dependent flow-mediated dilation of the brachial artery (FMD BA), and carotid IMT were studied. GNB3 (rs5443) and NOS3 (rs2070744) genotyping was performed by TaqMan probes (CFX96™Real-Time PCR). Results. The connection of NOS3 (rs2070744) with decreased total NO metabolites (F=71.11; p<0.001), reduced NOS3 genes transcription activity (F=8.71; p<0.001) and increased sVCAM-1 (F=6.96; p=0.002), especially in the C-allele carriers (particularly in CC-genotype patients with lower NO - 16.46% and 40.88%; p<0.001), lowered the transcription activity of NOS3 gene - 46.03% 7 times (p<0.001), and become higher sVCAM-1 - 35.48% and 89.48% (p<0.001), respectively. ANOVA did not confirm the association of GNB3 (rs5443) gene with endothelial function and carotid IMT. Severe EAH was associated with increased carotid IMT - 50.0% (p<0.001) and 57.14% (p=0.007), wider carotid arteries - 17.36% (p=0.012) and 21.79% (p=0.004), and decreased NOS3 genes transcription activity - 34.54% (p=0.003). Atherosclerotic plaques were unilateral - 24.77% (χ²=5.35; p=0.021) or bilateral - 27.62% (χ²=5.79; p=0.016). IMT---gt---0.9 mm was followed by a higher BP (p<0.001), FMD BA 11.80% decrease with compensatory increase in carotid arteries diameters - 17.38% and 21.99% (p<0.001) and sVCAM-1 by 20.49% (p=0.005). Conclusion. NOS3 (rs2070744), but not GNB3 (rs5443), gene associated with the essential arterial hypertension severity relying upon the endothelial function impairment and NOS3 genes reduced transcription activity.

STAT3 inhibitor mitigates cerebral amyloid angiopathy and parenchymal amyloid plaques while improving cognitive functions and brain networks

Previous reports indicate a potential role for signal transducer and activator of transcription 3 (STAT3) in amyloid-β (Aβ) processing and neuritic plaque pathogenesis. In the present study, the impact of STAT3 inhibition on cognition, cerebrovascular function, amyloid pathology, oxidative stress, and neuroinflammation was studied using in vitro and in vivo models of Alzheimer's disease (AD)-related pathology. For in vitro experiments, human brain vascular smooth muscle cells (HBVSMC) and human brain microvascular endothelial cells (HBMEC) were used, and these cultured cells were exposed to Aβ peptides followed by measurement of activated forms of STAT3 expression and reactive oxygen species (ROS) generation. Further, 6 months old 5XFAD/APOE4 (5XE4) mice and age-matched negative littermates were used for in vivo experiments. These mice were treated with STAT3 specific inhibitor, LLL-12 for 2 months followed by neurobehavioral and histopathological assessment. In vitro experiments showed exposure of cerebrovascular cells to Aβ peptides upregulated activated forms of STAT3 and produced STAT3-mediated vascular oxidative stress. 5XE4 mice treated with the STAT3-specific inhibitor (LLL-12) improved cognitive functions and functional connectivity and augmented cerebral blood flow. These functional improvements were associated with a reduction in neuritic plaques, cerebral amyloid angiopathy (CAA), oxidative stress, and neuroinflammation. Reduction in amyloid precursor protein (APP) processing and attenuation of oxidative modification of lipoprotein receptor related protein-1 (LRP-1) were identified as potential underlying mechanisms. These results demonstrate the broad impact of STAT3 on cognitive functions, parenchymal and vascular amyloid pathology and highlight the therapeutic potential of STAT3 specific inhibition for treatment of AD and CAA.

Exploiting the STAT3 Nexus in Cancer-Associated Fibroblasts to Improve Cancer Therapy

The tumor microenvironment (TME) is composed of a heterogenous population of cells that exist alongside the extracellular matrix and soluble components. These components can shape an environment that is conducive to tumor growth and metastatic spread. It is well-established that stromal cancer-associated fibroblasts (CAFs) in the TME play a pivotal role in creating and maintaining a growth-permissive environment for tumor cells. A growing body of work has uncovered that tumor cells recruit and educate CAFs to remodel the TME, however, the mechanisms by which this occurs remain incompletely understood. Recent studies suggest that the signal transducer and activator of transcription 3 (STAT3) is a key transcription factor that regulates the function of CAFs, and their crosstalk with tumor and immune cells within the TME. CAF-intrinsic STAT3 activity within the TME correlates with tumor progression, immune suppression and eventually the establishment of metastases. In this review, we will focus on the roles of STAT3 in regulating CAF function and their crosstalk with other cells constituting the TME and discuss the utility of targeting STAT3 within the TME for therapeutic benefit.

Hydrogen sulfide prevents arterial medial calcification in rats with diabetic nephropathy

BACKGROUND

Arterial medial calcification (AMC) is associated with a high incidence of cardiovascular risk in patients with type 2 diabetes and chronic kidney disease. Here, we tested whether hydrogen sulfide (H2S) can prevent AMC in rats with diabetic nephropathy (DN).

METHODS

DN was induced by a single injection of streptozotocin and high-fat diet (45% kcal as fat) containing 0.75% adenine in Sprague-Dawley rats for 8 weeks.

RESULTS

Rats with DN displayed obvious calcification in aorta, and this was significantly alleviated by Sodium Hydrosulfide (NaHS, a H2S donor, 50 μmol/kg/day for 8 weeks) treatment through decreasing calcium and phosphorus content, ALP activity and calcium deposition in aorta. Interestingly, the main endogenous H2S generating enzyme activity and protein expression of cystathionine-γ-lyase (CSE) were largely reduced in the arterial wall of DN rats. Exogenous NaHS treatment restored CSE activity and its expression, inhibited aortic osteogenic transformation by upregulating phenotypic markers of smooth muscle cells SMα-actin and SM22α, and downregulating core binding factor α-1 (Cbfα-1, a key factor for bone formation), protein expressions in rats with DN when compared to the control group. NaHS administration also significantly reduced Stat3 activation, cathepsin S (CAS) activity and TGF-β1 protein level, and improved aortic elastin expression.

CONCLUSIONS

H2S may have a clinical significance for treating AMC in people with DN by reducing Stat3 activation, CAS activity, TGF-β1 level and increasing local elastin level.

Silencing IL12p35 Promotes Angiotensin II-Mediated Abdominal Aortic Aneurysm through Activating the STAT4 Pathway

Background and Purpose. Abdominal aortic aneurysm (AAA) is a chronic inflammatory disorder and the important causes of death among men over the age of 65 years. Interleukin-12p35 (IL12p35) is an inflammatory cytokine that participates in a variety of inflammatory diseases. However, the role of IL12p35 in the formation and development of AAA is still unknown. Experimental Approach. Male apolipoprotein E-deficient (Apoe^−/−) mice were generated and infused with 1.44 mg/kg angiotensin II (Ang II) per day. We found that IL12p35 expression was noticeably increased in the murine AAA aorta and isolated aortic smooth muscle cells (SMCs) after Ang II stimulation. IL12p35 silencing promoted Ang II-induced AAA formation and rupture in Apoe^−/− mice. IL12p35 silencing markedly increased the expression of inflammatory cytokines, including IL-1β, IL-6, and tumor necrosis factor-α (TNF-α), in both the serum and AAA aorta. Additionally, IL12p35 silencing exacerbated SMC apoptosis in Apoe^−/− mice after Ang II infusion. IL12p35 silencing significantly increased signal transducer and activator of transcription (STAT) 4 phosphorylation levels in AAA mice, and STAT4 knockdown abolished the IL12p35-mediated proinflammatory response and SMC apoptosis. Interpretation. Silencing IL12p35 promotes AAA formation by activating the STAT4 pathway, and IL12p35 may serve as a novel and promising therapeutic target for AAA treatment.

Activation of the Central Renin-Angiotensin System Causes Local Cerebrovascular Dysfunction

[Figure: see text].

Reduction of serum-induced endothelial STAT3(Y705) activation is associated with preeclampsia

OBJECTIVES

Preeclampsia is associated with maternal morbidity and mortality during pregnancy, and also an increased cardiovascular disease (CVD) risk later in life. During preeclampsia, alterations in secreted placental factors leading to systemic maternal endothelial dysfunction are evident. However, little is known about the associated endothelial intracellular signaling. STAT3 is a latent cytoplasmic transcription factor involved in endothelial cell differentiation, survival, and angiogenesis. We aimed to test if preeclampsia and preeclampsia-related placental factors could alter serum-induced STAT3(Y705) activation in endothelial cells. Furthermore, if altered serum-induced endothelial STAT3 (Y705) activation is related to post-preeclamptic CVD risk.

STUDY DESIGN

HUVECs were used as a model of maternal endothelium. Experiments entailed addition of 20% human pregnancy serum as well as addition of recombinant PlGF, sFLT1 and VEGF-A_165a to the cells.

MAIN OUTCOME MEASURES

Levels of pSTAT3(Y705) related to STAT3 levels were evaluated by immunoblotting analysis.

RESULTS

Our results show that preeclamptic serum induces significantly lower STAT3(Y705) phosphorylation compared with uncomplicated pregnancy serum (P = 0.0089) in endothelial cells. Furthermore, STAT3(Y705) phosphorylation was not changed upon addition of PlGF, sFLT1, or VEGF-A_165a together with pregnancy sera compared with sera alone. Finally, sera from women with previous preeclampsia and current hypertension and carotid atherosclerotic plaques show significantly lower STAT3(Y705) phosphorylation capabilities compared with healthy women with previous uncomplicated pregnancies 8-18 years after deliveries (P = 0.029).

CONCLUSIONS

Reduction in serum-induced endothelial STAT3(Y705) activation may play an important role in the preeclampsia-associated endothelial dysfunction. Additionally, reduced endothelial STAT3(Y705) phosphorylation may contribute to increased post-preeclamptic CVD risk 8-18 years after delivery.

UPLC-MS-Based Serum Metabolomics Reveals Potential Biomarkers of Ang II-Induced Hypertension in Mice

Hypertension is caused by polygenic inheritance and the interaction of various environmental factors. Abnormal function of the renin-angiotensin-aldosterone system (RAAS) is closely associated with changes in blood pressure. As an essential factor in the RAAS, angiotensin II (Ang II) contributes to vasoconstriction and inflammatory responses. However, the effects of overproduction of Ang II on the whole body-metabolism have been unclear. In this study, we established a hypertensive mouse model by micro-osmotic pump perfusion of Ang II, and the maximum systolic blood pressure reached 140 mmHg after 2 weeks. By ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry, the metabolites in the serum of hypertensive model and control mice were analyzed. Partial least squares discriminant analysis (PLS-DA) in both positive and negative ionization modes showed clear separation of the two groups. Perfusion of Ang II induced perturbations of multiple metabolic pathways in mice, such as steroid hormone biosynthesis and galactose metabolism. Tandem mass spectrometry revealed 40 metabolite markers with potential diagnostic value for hypertension. Our data indicate that non-targeted metabolomics can reveal biochemical pathways associated with Ang II-induced hypertension. Although researches about the clinical use of these metabolites as potential biomarkers in hypertension is still needed, the current study improves the understanding of systemic metabolic response to sustained release of Ang II in hypertensive mice, providing a new panel of biomarkers that may be used to predict blood pressure fluctuations in the early stages of hypertension.

Circulating miR-155 and JAK2/STAT3 Axis in Acute Ischemic Stroke Patients and Its Relation to Post-Ischemic Inflammation and Associated Ischemic Stroke Risk Factors

Background

“Micro RNAs and their target genes recently have been identified to play a crucial role in the molecular pathogenesis of post-stroke ischemic cellular injury, which elucidates their new role in ischemic stroke diagnosis and therapy”. Thus, we evaluated the relative serum expression of miR-155, an inflammatory micro RNA, and the mRNAs (JAK2/STAT3) in acute ischemic stroke patients and its associations with the inflammatory cytokine TNF-α and different stroke risk factors.

Subjects and Methods

The relative expression of serum miR-155 and mRNAs (JAK2/STAT3) was assessed using RT-PCR, serum TNF-α was measured using ELIZA in 46 acute ischemic stroke patients and 50 control subjects. Receiver operating characteristic (ROC) curve was constructed to assess the specificity and sensitivity of circulating miR-155, JAK2/STAT3 as biomarkers for acute ischemic stroke.

Results

Circulating miR-155, JAK2/STAT3 were significantly up-regulated among stroke patients (8.5, 2.9, 4.2 fold respectively, P<0.001) with significant increase in TNF-α (263.8 ± 10.7 pg/mL, P <0.001). MiR-155, JAK2/STAT3 were positively correlated with TNF-α. MiR-155, JAK2/STAT3 were significantly increased in stroke patients and associated with risk factors such as hypertension, carotid atherosclerosis, and atrial fibrillation. Our study revealed that miR-155 has diagnostic accuracy for acute ischemic stroke where AUC=0.9, (P<0.001).

Conclusion

The elevated expressions of circulating miR-155, JAK2/STAT3, and TNF-α in acute ischemic stroke patients could trigger post-stroke cellular inflammation. MiR-155 could be used as potential inflammatory biomarker for acute ischemic stroke. However, further clinical studies are still needed to determine the exact role of miRNAs and different signal transduction expressions in the stage of acute ischemic stroke.

Diabetes and hypertension: Pivotal involvement of purinergic signaling

Diabetes mellitus (DM) and hypertension are highly prevalent worldwide health problems and frequently associated with severe clinical complications, such as diabetic cardiomyopathy, nephropathy, retinopathy, neuropathy, stroke, and cardiac arrhythmia, among others. Despite all existing research results and reasonable speculations, knowledge about the role of purinergic system in individuals with DM and hypertension remains restricted. Purinergic signaling accounts for a complex network of receptors and extracellular enzymes responsible for the recognition and degradation of extracellular nucleotides and adenosine. The main components of this system that will be presented in this review are: P1 and P2 receptors and the enzymatic cascade composed by CD39 (NTPDase; with ATP and ADP as a substrate), CD73 (5′-nucleotidase; with AMP as a substrate), and adenosine deaminase (ADA; with adenosine as a substrate). The purinergic system has recently emerged as a central player in several physiopathological conditions, particularly those linked to inflammatory responses such as diabetes and hypertension. Therefore, the present review focuses on changes in both purinergic P1 and P2 receptor expression as well as the activities of CD39, CD73, and ADA in diabetes and hypertension conditions. It can be postulated that the manipulation of the purinergic axis at different levels can prevent or exacerbate the insurgency and evolution of diabetes and hypertension working as a compensatory mechanism.

Vasculo-Neuronal Coupling and Neurovascular Coupling at the Neurovascular Unit: Impact of Hypertension

Components of the neurovascular unit (NVU) establish dynamic crosstalk that regulates cerebral blood flow and maintain brain homeostasis. Here, we describe accumulating evidence for cellular elements of the NVU contributing to critical physiological processes such as cerebral autoregulation, neurovascular coupling, and vasculo-neuronal coupling. We discuss how alterations in the cellular mechanisms governing NVU homeostasis can lead to pathological changes in which vascular endothelial and smooth muscle cell, pericyte and astrocyte function may play a key role. Because hypertension is a modifiable risk factor for stroke and accelerated cognitive decline in aging, we focus on hypertension-associated changes on cerebral arteriole function and structure, and the molecular mechanisms through which these may contribute to cognitive decline. We gather recent emerging evidence concerning cognitive loss in hypertension and the link with vascular dementia and Alzheimer’s disease. Collectively, we summarize how vascular dysfunction, chronic hypoperfusion, oxidative stress, and inflammatory processes can uncouple communication at the NVU impairing cerebral perfusion and contributing to neurodegeneration.

WWP2 regulates SIRT1-STAT3 acetylation and phosphorylation involved in hypertensive angiopathy

WWP2 is a HECT‐type E3 ubiquitin ligase that regulates various physiological and pathological activities by binding to different substrates, but its function and regulatory mechanism in vascular smooth muscle cells (VSMCs) are still unknown. Here, we clarified the role of WWP2 in the regulation of SIRT1‐STAT3 and the impact of this regulatory process in VSMCs. We demonstrated that WWP2 expression was significantly increased in angiotensin II‐induced VSMCs model. Knockdown of WWP2 significantly inhibited angiotensin II‐induced VSMCs proliferation, migration and phenotypic transformation, whereas overexpression of WWP2 had opposite effects. In vivo experiments showed that vascular smooth muscle‐specific WWP2 knockout mice significantly relieved angiotensin II‐induced hypertensive angiopathy. Mechanistically, mass spectrometry and co‐immunoprecipitation assays identified that WWP2 is a novel interacting protein of SIRT1 and STAT3. Moreover, WWP2 formed a complex with SIRT1‐STAT3, inhibiting the interaction between SIRT1 and STAT3, then reducing the inhibitory effect of SIRT1 on STAT3, ensuing promoting STAT3‐K685 acetylation and STAT3‐Y705 phosphorylation in angiotensin II‐induced VSMCs and mice. In conclusion, WWP2 modulates hypertensive angiopathy by regulating SIRT1‐STAT3 and WWP2 suppression in VSMCs can alleviate hypertensive angiopathy vitro and vivo. These findings provide new insights into the treatment of hypertensive vascular diseases.

P-STAT3 Inhibition Activates Endoplasmic Reticulum Stress-Induced Splenocyte Apoptosis in Chronic Stress

Chronic stress leads to immunosuppression and induces splenocyte apoptosis. STAT3 is a transcription factor that regulates immunity and apoptosis; however, it is unclear whether the increased expression of phosphorylated STAT3 (p-STAT3) observed in chronic stress is related to splenocyte apoptosis. To explore the relationship between splenocyte apoptosis and STAT3 in chronic stress, we treated rats undergoing a 21-day chronic restraint stress program with the STAT3 inhibitor S3I-201. This chronic stress model was verified by observing rats’ behavior and measuring their serum corticosterone levels. Chronic stress led to increased expression of anti-inflammatory cytokines, and p-STAT3 inhibition enhanced splenocyte apoptosis in chronic stress. We detected key proteins in three apoptotic pathways to determine which pathway mediated increasing splenocyte apoptosis and found that the death receptor pathway was the main apoptotic pathway that occurred in the spleen during chronic stress. The unfolded protein response (UPR) was also activated, but the Bcl-2 family was not involved in chronic stress. P-STAT3 inhibition had no influence on the Bcl-2 family and the death receptor pathway; however, p-STAT3 inhibition disrupted the pro-survival function of the UPR by decreasing the expression of ATF6α and p-IRE1α. Furthermore, p-STAT3 inhibition activated endoplasmic reticulum stress by promoting the expression of CHOP, p-JNK, and procaspase-12. Collectively, these findings indicate that the increased p-STAT3 expression during chronic stress may promote splenocyte survival by activating the UPR. Consequently, STAT3 and the UPR may be considered as potential therapeutic targets for chronic stress in the future.

Interleukin-9 Deletion Relieves Vascular Dysfunction and Decreases Blood Pressure via the STAT3 Pathway in Angiotensin II-Treated Mice

Background

Multiple interleukin (IL) family members were reported to be closely related to hypertension. We aimed to investigate whether IL-9 affects angiotensin II- (Ang II-) induced hypertension in mice.

Methods

Mice were treated with Ang II, and IL-9 expression was determined. In addition, effects of IL-9 knockout (KO) on blood pressure were observed in Ang II-infused mice. To determine whether the effects of IL-9 on blood pressure was mediated by the signal transducer and activator of the transcription 3 (STAT3) pathway, Ang II-treated mice were given S31-201. Furthermore, circulating IL-9 levels in patients with hypertension were measured.

Results

Ang II treatment increased serum and aortic IL-9 expression in a dose-dependent manner; IL-9 levels were the highest in the second week and continued to remain high into the fourth week after the treatment. IL-9 KO downregulated proinflammatory cytokine expression, whereas it upregulated anti-inflammatory cytokine levels, relieved vascular dysfunction, and decreased blood pressure in Ang II-infused mice. IL-9 also reduced smooth muscle 22α (SM22α (SM22

Conclusions

IL-9 KO alleviates inflammatory response, prevents phenotypic transformation of smooth muscle, reduces vascular dysfunction, and lowers blood pressure via the STAT3 pathway in Ang II-infused mice. IL-9 might be a novel target for the treatment and prevention of clinical hypertension.

Hydrogen Sulfide Prevents Elastin Loss and Attenuates Calcification Induced by High Glucose in Smooth Muscle Cells through Suppression of Stat3/Cathepsin S Signaling Pathway

Vascular calcification can be enhanced by hyperglycemia. Elastin loss in tunica media promotes the osteogenic transformation of smooth muscle cells (SMCs) and involves arterial medial calcification (AMC) that is associated with a high incidence of cardiovascular risk in patients with type 2 diabetes. Here, we tested whether hydrogen sulfide (H₂S), an endogenous gaseous mediator, can prevent elastin loss and attenuate calcification induced by high glucose in SMCs. Calcification was induced by high glucose (4500 mg/L) in human aortic SMCs (HASMCs) under the condition of calcifying medium containing 10 mM β-glycerophosphate (β-GP). The experiments showed that NaHS (an H₂S donor, 100 μM) mitigated the calcification of HASMCs treated with high glucose by decreasing calcium and phosphorus levels, calcium deposition and ALP activity and inhibited osteogenic transformation by increasing SMα-actin and SM22α, two phenotypic markers of smooth muscle cells, and decreasing core binding factor α-1 (Cbfα-1), a key factor in bone formation, protein expressions in HASMCs. Moreover, NaHS administration inhibited the activation of Stat3, cathepsin S (CAS) activity and its expression, but increased the level of elastin protein. Pharmacological inhibition or gene silencing Stat3 not only reversed elastin loss, but also attenuated CAS expression. Inhibition of CAS alleviated, while CAS overexpression exacerbated, elastin loss. Interestingly, overexpression of wild type (WT)-Stat3, but not its mutant C259S, elevated CAS protein expression and reduced elastin level. Moreover, NaHS induced S-sulfhydration in WT, but not in the C259S Stat3. These data suggest that H₂S may directly regulate Cys259 residue in Stat3 and then impair its signaling function. Our data indicate that H₂S may attenuate vascular calcification by upregulating elastin level through the inhibition of Stat3/CAS signaling.

Targeted inhibition of STAT3 as a potential treatment strategy for atherosclerosis

Atherosclerosis is the main pathological basis of ischemic cardiovascular and cerebrovascular diseases and has attracted more attention in recent years. Multiple studies have demonstrated that the signal transducer and activator of transcription 3 (STAT3) plays essential roles in the process of atherosclerosis. Moreover, aberrant STAT3 activation has been shown to contribute to the occurrence and development of atherosclerosis. Therefore, the study of STAT3 inhibitors has gradually become a focal research topic. In this review, we describe the crucial roles of STAT3 in endothelial cell dysfunction, macrophage polarization, inflammation, and immunity during atherosclerosis. STAT3 in mitochondria is mentioned as well. Then, we present a summary and classification of STAT3 inhibitors, which could offer potential treatment strategies for atherosclerosis. Furthermore, we enumerate some of the problems that have interfered with the development of mature therapies utilizing STAT3 inhibitors to treat atherosclerosis. Finally, we propose ideas that may help to solve these problems to some extent. Collectively, this review may be useful for developing future STAT3 inhibitor therapies for atherosclerosis.

Hypertension, dietary salt and cognitive impairment

Dementia is growing at an alarming rate worldwide. Although Alzheimer disease is the leading cause, over 50% of individuals diagnosed with Alzheimer disease have vascular lesions at autopsy. There has been an increasing appreciation of the pathogenic role of vascular risk factors in cognitive impairment caused by neurodegeneration. Midlife hypertension is a leading risk factor for late-life dementia. Hypertension alters cerebrovascular structure, impairs the major factors regulating the cerebral microcirculation, and promotes Alzheimer pathology. Experimental studies have identified brain perivascular macrophages as the major free radical source mediating neurovascular dysfunction of hypertension. Recent evidence indicates that high dietary salt may also induce cognitive impairment. Contrary to previous belief, the effect is not necessarily associated with hypertension and is mediated by a deficit in endothelial nitric oxide. Collectively, the evidence suggests a remarkable cellular diversity of the impact of vascular risk factors on the cerebral vasculature and cognition. Whereas long-term longitudinal epidemiological studies are needed to resolve the temporal relationships between vascular risk factors and cognitive dysfunction, single-cell molecular studies of the vasculature in animal models will provide a fuller mechanistic understanding. This knowledge is critical for developing new preventive, diagnostic, and therapeutic approaches for these devastating diseases of the mind.

Mineralocorticoid receptor antagonism improves parenchymal arteriole dilation via a TRPV4-dependent mechanism and prevents cognitive dysfunction in hypertension

Hypertension and mineralocorticoid receptor activation cause cerebral parenchymal arteriole remodeling; this can limit cerebral perfusion and contribute to cognitive dysfunction. We used a mouse model of angiotensin II-induced hypertension to test the hypothesis that mineralocorticoid receptor activation impairs both transient receptor potential vanilloid (TRPV)4-mediated dilation of cerebral parenchymal arterioles and cognitive function. Mice (16-18 wk old, male, C57Bl/6) were treated with angiotensin II (800 ng·kg-1·min-1) with or without the mineralocorticoid receptor antagonist eplerenone (100 mg·kg-1·day-1) for 4 wk; sham mice served as controls. Data are presented as means ± SE; n = 5-14 mice/group. Eplerenone prevented the increased parenchymal arteriole myogenic tone and impaired carbachol-induced (10-9-10-5 mol/l) dilation observed during hypertension. The carbachol-induced dilation was endothelium-derived hyperpolarization mediated because it could not be blocked by N-nitro-l-arginine methyl ester (10-5 mol/l) and indomethacin (10-4 mol/l). We used GSK2193874 (10-7 mol/l) to confirm that in all groups this dilation was dependent on TRPV4 activation. Dilation in response to the TRPV4 agonist GSK1016790A (10-9-10-5 mol/l) was also reduced in hypertensive mice, and this defect was corrected by eplerenone. In hypertensive and eplerenone-treated animals, TRPV4 inhibition reduced myogenic tone, an effect that was not observed in arterioles from control animals. Eplerenone treatment also improved cognitive function and reduced microglia density in hypertensive mice. These data suggest that the mineralocorticoid receptor is a potential therapeutic target to improve cerebrovascular function and cognition during hypertension. NEW & NOTEWORTHY Vascular dementia is a growing public health issue that lacks effective treatments. Transient receptor potential vanilloid (TRPV)4 channels are important regulators of parenchymal arteriole dilation, and they modulate myogenic tone. The data presented here suggest that TRPV4 channel expression is regulated by the mineralocorticoid receptor (MR). MR blockade also improves cognitive function during hypertension. MR blockade might be a potential therapeutic approach to improve cerebrovascular function and cognition in patients with hypertension.

Angiotensin II Attenuates the Bioactivities of Human Endothelial Progenitor Cells via Downregulation of β2-Adrenergic Receptor

Cross talks between the renin-angiotensin system (RAS), sympathetic nervous system, and vascular homeostasis are tightly coordinated in hypertension. Angiotensin II (Ang II), a key factor in RAS, when abnormally activated, affects the number and bioactivity of circulating human endothelial progenitor cells (hEPCs) in hypertensive patients. In this study, we investigated how the augmentation of Ang II regulates adrenergic receptor-mediated signaling and angiogenic bioactivities of hEPCs. Interestingly, the short-term treatment of hEPCs with Ang II drastically attenuated the expression of beta-2 adrenergic receptor (ADRB2), but did not alter the expression of beta-1 adrenergic receptor (ADRB1) and Ang II type 1 receptor (AT1R). EPC functional assay clearly demonstrated that the treatment with ADRB2 agonists significantly increased EPC bioactivities including cell proliferation, migration, and tube formation abilities. However, EPC bioactivities were decreased dramatically when treated with Ang II. Importantly, the attenuation of EPC bioactivities by Ang II was restored by treatment with an AT1R antagonist (telmisartan; TERT). We found that AT1R binds to ADRB2 in physiological conditions, but this binding is significantly decreased in the presence of Ang II. Furthermore, TERT, an Ang II-AT1R interaction blocker, restored the interaction between AT1R and ADRB2, suggesting that Ang II might induce the dysfunction of EPCs via downregulation of ADRB2, and an AT1R blocker could prevent Ang II-mediated ADRB2 depletion in EPCs. Taken together, our report provides novel insights into potential therapeutic approaches for hypertension-related cardiovascular diseases.

Genome-Wide Inhibition of Pro-atherogenic Gene Expression by Multi-STAT Targeting Compounds as a Novel Treatment Strategy of CVDs

Cardiovascular diseases (CVDs), including atherosclerosis, are globally the leading cause of death. Key factors contributing to onset and progression of atherosclerosis include the pro-inflammatory cytokines Interferon (IFN)α and IFNγ and the Pattern Recognition Receptor (PRR) Toll-like receptor 4 (TLR4). Together, they trigger activation of Signal Transducer and Activator of Transcription (STAT)s. Searches for compounds targeting the pTyr-SH2 interaction area of STAT3, yielded many small molecules, including STATTIC and STX-0119. However, many of these inhibitors do not seem STAT3-specific. We hypothesized that multi-STAT-inhibitors that simultaneously block STAT1, STAT2, and STAT3 activity and pro-inflammatory target gene expression may be a promising strategy to treat CVDs. Using comparative in silico docking of multiple STAT-SH2 models on multi-million compound libraries, we identified the novel multi-STAT inhibitor, C01L_F03. This compound targets the SH2 domain of STAT1, STAT2, and STAT3 with the same affinity and simultaneously blocks their activity and expression of multiple STAT-target genes in HMECs in response to IFNα. The same in silico and in vitro multi-STAT inhibiting capacity was shown for STATTIC and STX-0119. Moreover, C01L_F03, STATTIC and STX-0119 were also able to affect genome-wide interactions between IFNγ and TLR4 by commonly inhibiting pro-inflammatory and pro-atherogenic gene expression directed by cooperative involvement of STATs with IRFs and/or NF-κB. Moreover, we observed that multi-STAT inhibitors could be used to inhibit IFNγ+LPS-induced HMECs migration, leukocyte adhesion to ECs as well as impairment of mesenteric artery contractility. Together, this implicates that application of a multi-STAT inhibitory strategy could provide great promise for the treatment of CVDs.

Hypertension and increased endothelial mechanical stretch promote monocyte differentiation and activation: roles of STAT3, interleukin 6 and hydrogen peroxide

Aims

Monocytes play an important role in hypertension. Circulating monocytes in humans exist as classical, intermediate, and non-classical forms. Monocyte differentiation can be influenced by the endothelium, which in turn is activated in hypertension by mechanical stretch. We sought to examine the role of increased endothelial stretch and hypertension on monocyte phenotype and function.

Methods and results

Human monocytes were cultured with confluent human aortic endothelial cells undergoing either 5% or 10% cyclical stretch. We also characterized circulating monocytes in normotensive and hypertensive humans. In addition, we quantified accumulation of activated monocytes and monocyte-derived cells in aortas and kidneys of mice with Angiotensin II-induced hypertension. Increased endothelial stretch enhanced monocyte conversion to CD14++CD16+ intermediate monocytes and monocytes bearing the CD209 marker and markedly stimulated monocyte mRNA expression of interleukin (IL)-6, IL-1β, IL-23, chemokine (C-C motif) ligand 4, and tumour necrosis factor α. STAT3 in monocytes was activated by increased endothelial stretch. Inhibition of STAT3, neutralization of IL-6 and scavenging of hydrogen peroxide prevented formation of intermediate monocytes in response to increased endothelial stretch. We also found evidence that nitric oxide (NO) inhibits formation of intermediate monocytes and STAT3 activation. In vivo studies demonstrated that humans with hypertension have increased intermediate and non-classical monocytes and that intermediate monocytes demonstrate evidence of STAT3 activation. Mice with experimental hypertension exhibit increased aortic and renal infiltration of monocytes, dendritic cells, and macrophages with activated STAT3.

Conclusions

These findings provide insight into how monocytes are activated by the vascular endothelium during hypertension. This is likely in part due to a loss of NO signalling and increased release of IL-6 and hydrogen peroxide by the dysfunctional endothelium and a parallel increase in STAT activation in adjacent monocytes. Interventions to enhance bioavailable NO, reduce IL-6 or hydrogen peroxide production or to inhibit STAT3 may have anti-inflammatory roles in hypertension and related conditions.

Targeted inhibition of STATs and IRFs as a potential treatment strategy in cardiovascular disease

Key factors contributing to early stages of atherosclerosis and plaque development include the pro-inflammatory cytokines Interferon (IFN)α, IFNγ and Interleukin (IL)-6 and Toll-like receptor 4 (TLR4) stimuli. Together, they trigger activation of Signal Transducer and Activator of Transcription (STAT) and Interferon Regulatory Factor (IRF) families. In particular, STAT1, 2 and 3; IRF1 and 8 have recently been recognized as prominent modulators of inflammation, especially in immune and vascular cells during atherosclerosis. Moreover, inflammation-mediated activation of these STATs and IRFs coordinates a platform for synergistic amplification leading to pro-atherogenic responses.

Searches for STAT3-targeting compounds, exploring the pTyr-SH2 interaction area of STAT3, yielded many small molecules including natural products. Only a few inhibitors for other STATs, but none for IRFs, are described. Promising results for several STAT3 inhibitors in recent clinical trials predicts STAT3-inhibiting strategies may find their way to the clinic. However, many of these inhibitors do not seem STAT-specific, display toxicity and are not very potent. This illustrates the need for better models, and screening and validation tools for novel STAT and IRF inhibitors.

This review presents a summary of these findings. It postulates STAT1, STAT2 and STAT3 and IRF1 and IRF8 as interesting therapeutic targets and targeted inhibition could be a potential treatment strategy in CVDs. In addition, it proposes a pipeline approach that combines comparative in silico docking of STAT-SH2 and IRF-DBD models with in vitro STAT and IRF activation inhibition validation, as a novel tool to screen multi-million compound libraries and identify specific inhibitors for STATs and IRFs.

Cellular and Oxidative Mechanisms Associated with Interleukin-6 Signaling in the Vasculature

Reactive oxygen species, particularly superoxide, promote endothelial dysfunction and alterations in vascular structure. It is increasingly recognized that inflammatory cytokines, such as interleukin-6 (IL-6), contribute to endothelial dysfunction and vascular hypertrophy and fibrosis. IL-6 is increased in a number of cardiovascular diseases, including hypertension. IL-6 is also associated with a higher incidence of future cardiovascular events and all-cause mortality. Both immune and vascular cells produce IL-6 in response to a number of stimuli, such as angiotensin II. The vasculature is responsive to IL-6 produced from vascular and non-vascular sources via classical IL-6 signaling involving a membrane-bound IL-6 receptor (IL-6R) and membrane-bound gp130 via Jak/STAT as well as SHP2-dependent signaling pathways. IL-6 signaling is unique because it can also occur via a soluble IL-6 receptor (sIL-6R) which allows for IL-6 signaling in tissues that do not normally express IL-6R through a process referred to as IL-6 trans-signaling. IL-6 signaling mediates a vast array of effects in the vascular wall, including endothelial activation, vascular permeability, immune cell recruitment, endothelial dysfunction, as well as vascular hypertrophy and fibrosis. Many of the effects of IL-6 on vascular function and structure are representative of loss or reductions in nitric oxide (NO) bioavailability. IL-6 has direct effects on endothelial nitric oxide synthase activity and expression as well as increasing vascular superoxide, which rapidly inactivates NO thereby limiting NO bioavailability. The goal of this review is to highlight both the cellular and oxidative mechanisms associated with IL-6-signaling in the vascular wall in general, in hypertension, and in response to angiotensin II.

Interleukin 22 Promotes Blood Pressure Elevation and Endothelial Dysfunction in Angiotensin II-Treated Mice

BACKGROUND

CD4+ T helper (Th) cells, including Th1, Th2, and Th17 cells, play critical roles in angiotensin II-induced hypertension. Th22 cells, a novel subset of Th cells, take part in cardiovascular diseases by producing IL-22 (interleukin 22). This study aimed to investigate whether IL-22 is involved in hypertension.

METHODS AND RESULTS

Th22 cells and IL-22 levels were detected in angiotensin II-infused mice, and the results showed that Th22 cells and IL-22 levels significantly increased. To determine the effect of Th22/IL-22 on blood pressure regulation, angiotensin II-infused mice were treated with recombinant mouse IL-22, an anti-IL-22 neutralizing monoclonal antibody, or control. Treatment with recombinant IL-22 resulted in increased blood pressure, amplified inflammatory responses, and aggravated endothelial dysfunction, whereas the anti-IL-22 neutralizing monoclonal antibody decreased blood pressure, reduced inflammatory responses, and attenuated endothelial dysfunction. To determine whether the STAT3 (signal transducer and activator of transcription 3) pathway mediates the effect of IL-22 on blood pressure regulation, the special STAT3 pathway inhibitor S31-201 was administered to mice treated with recombinant IL-22. S31-201 treatment significantly ameliorated the IL-22 effects of increased blood pressure and endothelial dysfunction. In addition, serum IL-22 levels were significantly increased in hypertensive patients compared with healthy persons. Correlation analysis showed a positive correlation between IL-22 levels and blood pressure.

CONCLUSIONS

IL-22 amplifies the inflammatory response, induces endothelial dysfunction and promotes blood pressure elevation in angiotensin II-induced hypertensive mice. The STAT3 pathway mediates the effect of IL-22 on hypertension. Blocking IL-22 may be a novel therapeutic strategy to prevent and treat hypertension.

Genetic Interference With Endothelial PPAR-γ (Peroxisome Proliferator-Activated Receptor-γ) Augments Effects of Angiotensin II While Impairing Responses to Angiotensin 1-7

Pharmacological activation of PPAR-γ (peroxisome proliferator-activated receptor-γ) protects the vasculature. Much less is known on the cell-specific impact of PPAR-γ when driven by endogenous ligands. Recently, we found that endothelial PPAR-γ protects against angiotensin II-induced endothelial dysfunction. Here, we explored that concept further examining whether effects were sex dependent along with underlying mechanisms. We studied mice expressing a human dominant-negative mutation in PPAR-γ driven by the endothelial-specific vascular cadherin promoter (E-V290M), using nontransgenic littermates as controls. Acetylcholine (an endothelium-dependent agonist) produced similar relaxation of carotid arteries from nontransgenic and E-V290M mice. Incubation of isolated arteries with angiotensin II (1 nmol/L) overnight had no effect in nontransgenic, but reduced responses to acetylcholine by about 50% in male and female E-V290M mice (P<0.05). Endothelial function in E-V290M mice was restored to normal by inhibitors of superoxide (tempol), NADPH oxidase (VAS-2870), Rho kinase (Y-27632), ROCK2 (SLX-2119), NF-κB (nuclear factor-kappa B essential modulator-binding domain peptide), or interleukin-6 (neutralizing antibody). In addition, we hypothesized that PPAR-γ may influence the angiotensin 1-7 arm of the renin-angiotensin system. In the basilar artery, dilation to angiotensin 1-7 was selectively reduced in E-V290M mice by >50% (P<0.05), an effect reversed by Y-27632. Thus, effects of angiotensin II are augmented by interference with endothelial PPAR-γ through sex-independent mechanisms, involving oxidant-inflammatory signaling and ROCK2 (Rho kinase). The study also provides the first evidence that endothelial PPAR-γ interacts with angiotensin 1-7 responses. These critical roles for endothelial PPAR-γ have implications for pathophysiology and therapeutic approaches for vascular disease.

Cerebral Vascular Disease and Neurovascular Injury in Ischemic Stroke

The consequences of cerebrovascular disease are among the leading health issues worldwide. Large and small cerebral vessel disease can trigger stroke and contribute to the vascular component of other forms of neurological dysfunction and degeneration. Both forms of vascular disease are driven by diverse risk factors, with hypertension as the leading contributor. Despite the importance of neurovascular disease and subsequent injury after ischemic events, fundamental knowledge in these areas lag behind our current understanding of neuroprotection and vascular biology in general. The goal of this review is to address select key structural and functional changes in the vasculature that promote hypoperfusion and ischemia, while also affecting the extent of injury and effectiveness of therapy. In addition, as damage to the blood-brain barrier is one of the major consequences of ischemia, we discuss cellular and molecular mechanisms underlying ischemia-induced changes in blood-brain barrier integrity and function, including alterations in endothelial cells and the contribution of pericytes, immune cells, and matrix metalloproteinases. Identification of cell types, pathways, and molecules that control vascular changes before and after ischemia may result in novel approaches to slow the progression of cerebrovascular disease and lessen both the frequency and impact of ischemic events.

Perivascular macrophages mediate the neurovascular and cognitive dysfunction associated with hypertension

Hypertension is a leading risk factor for dementia, but the mechanisms underlying its damaging effects on the brain are poorly understood. Due to a lack of energy reserves, the brain relies on continuous delivery of blood flow to its active regions in accordance with their dynamic metabolic needs. Hypertension disrupts these vital regulatory mechanisms, leading to the neuronal dysfunction and damage underlying cognitive impairment. Elucidating the cellular bases of these impairments is essential for developing new therapies. Perivascular macrophages (PVMs) represent a distinct population of resident brain macrophages that serves key homeostatic roles but also has the potential to generate large amounts of reactive oxygen species (ROS). Here, we report that PVMs are critical in driving the alterations in neurovascular regulation and attendant cognitive impairment in mouse models of hypertension. This effect was mediated by an increase in blood-brain barrier permeability that allowed angiotensin II to enter the perivascular space and activate angiotensin type 1 receptors in PVMs, leading to production of ROS through the superoxide-producing enzyme NOX2. These findings unveil a pathogenic role of PVMs in the neurovascular and cognitive dysfunction associated with hypertension and identify these cells as a putative therapeutic target for diseases associated with cerebrovascular oxidative stress.

Senescent endothelial cells: Potential modulators of immunosenescence and ageing

Recent studies have demonstrated that the accumulation of senescent endothelial cells may be the primary cause of cardiovascular diseases. Because of their multifunctional properties, endothelial cells actively take part in stimulating the immune system and inflammation. In addition, ageing is characterized by the progressive deterioration of immune cells and a decline in the activation of the immune response. This results in a loss of the primary function of the immune system, which is eliminating damaged/senescent cells and neutralizing potential sources of harmful inflammatory reactions. In this review, we discuss cellular senescence and the senescence-associated secretory phenotype (SASP) of endothelial cells and summarize the link between endothelial cells and immunosenescence. We describe the possibility that age-related changes in Toll-like receptors (TLRs) and microRNAs can affect the phenotypes of senescent endothelial cells and immune cells via a negative feedback loop aimed at restraining the excessive pro-inflammatory response. This review also addresses the following questions: how do senescent endothelial cells influence ageing or age-related changes in the inflammatory burden; what is the connection between ECs and immunosenescence, and what are the crucial hypothetical pathways linking endothelial cells and the immune system during ageing.

Context-dependent effects of SOCS3 in angiotensin II-induced vascular dysfunction and hypertension in mice: mechanisms and role of bone marrow-derived cells

Carotid artery disease is a major contributor to stroke and cognitive deficits. Angiotensin II (Ang II) promotes vascular dysfunction and disease through mechanisms that include the IL-6/STAT3 pathway. Here, we investigated the importance of suppressor of cytokine signaling 3 (SOCS3) in models of Ang II-induced vascular dysfunction. We examined direct effects of Ang II on carotid arteries from SOCS3-deficient (SOCS3(+/-)) mice and wild-type (WT) littermates using organ culture and then tested endothelial function with acetylcholine (ACh). A low concentration of Ang II (1 nmol/l) did not affect ACh-induced vasodilation in WT but reduced that of SOCS3(+/-) mice by ∼50% (P < 0.05). In relation to mechanisms, effects of Ang II in SOCS3(+/-) mice were prevented by inhibitors of STAT3, IL-6, NF-κB, or superoxide. Systemic Ang II (1.4 mg/kg per day for 14 days) also reduced vasodilation to ACh in WT. Surprisingly, SOCS3 deficiency prevented most of the endothelial dysfunction. To examine potential underlying mechanisms, we performed bone marrow transplantation. WT mice reconstituted with SOCS3(+/-) bone marrow were protected from Ang II-induced endothelial dysfunction, whereas reconstitution of SOCS3(+/-) mice with WT bone marrow exacerbated Ang II-induced effects. The SOCS3 genotype of bone marrow-derived cells did not influence direct effects of Ang II on vascular function. These data provide new mechanistic insight into the influence of SOCS3 on the vasculature, including divergent effects depending on the source of Ang II. Bone marrow-derived cells deficient in SOCS3 protect against systemic Ang II-induced vascular dysfunction.

IL-6/STAT3 signaling in mice with dysfunctional type-2 ryanodine receptor

Mice with genetically modified cardiac ryanodine receptor (Ryr2^ADA/ADA mice) are impaired in regulation by calmodulin, develop severe cardiac hypertrophy and die about 2 weeks after birth. We hypothesized that the interleukin 6 (IL-6)/signal transducer and activator of transcription-3 (STAT3) signaling pathway has a role in the development of the Ryr2^ADA/ADA cardiac hypertrophy phenotype, and determined cardiac function and protein levels of IL-6, phosphorylation levels of STAT3, and downstream targets c-Fos and c-Myc in wild-type and RyR2^ADA/ADA mice, mice with a disrupted IL-6 gene, and mice treated with STAT3 inhibitor NSC74859. IL-6 protein levels were increased at postnatal day 1 but not day 10, whereas pSTAT3-Tyr705/STAT3 ratio and c-Fos and c-Myc protein levels increased in hearts of 10-day but not 1-day old Ryr2^ADA/ADA mice compared with wild type. Both STAT3 and pSTAT3-Tyr705 accumulated in the nuclear fraction of 10-day old Ryr2^ADA/ADA mice compared with wild type. Ryr2^{ADA /ADA} /IL-6^−/− mice lived 1.5 times longer, had decreased heart to body weight ratio, and reduced c-Fos and c-Myc protein levels. The STAT3 inhibitor NSC74859 prolonged life span by 1.3-fold, decreased heart to body weight ratio, increased cardiac performance, and decreased pSTAT-Tyr705/STAT3 ratio and IL-6, c-Fos and c-Myc protein levels of Ryr2^{ADA /ADA} mice. The results suggest that upregulation of IL-6 and STAT3 signaling contributes to cardiac hypertrophy and early death of mice with a dysfunctional ryanodine receptor. They further suggest that STAT3 inhibitors may be clinically useful agents in patients with altered Ca²⁺ handling in the heart.

Emerging translational approaches to target STAT3 signalling and its impact on vascular disease

Acute and chronic inflammation responses characterize the vascular remodelling processes in atherosclerosis, restenosis, pulmonary arterial hypertension, and angiogenesis. The functional and phenotypic changes in diverse vascular cell types are mediated by complex signalling cascades that initiate and control genetic reprogramming. The signalling molecule's signal transducer and activator of transcription 3 (STAT3) plays a key role in the initiation and continuation of these pathophysiological changes. This review highlights the pivotal involvement of STAT3 in pathological vascular remodelling processes and discusses potential translational therapies, which target STAT3 signalling, to prevent and treat cardiovascular diseases. Moreover, current clinical trials using highly effective and selective inhibitors of STAT3 signalling for distinct diseases, such as myelofibrosis and rheumatoid arthritis, are discussed with regard to their vascular (side-) effects and their potential to pave the way for a direct use of these molecules for the prevention or treatment of vascular diseases.

Ginkgolide A reduces inflammatory response in high-glucose-stimulated human umbilical vein endothelial cells through STAT3-mediated pathway

High-glucose-induced low-grade inflammation has been regarded as a key event in the onset and progression of endothelial dysfunction in diabetic vascular complications. Ginkgolide A (GA), a major compound from Ginkgo biloba extract, is widely used for the treatment of cardiovascular diseases and diabetic vascular complications. Here, its effect on high-glucose-stimulated vascular inflammation in human umbilical vein endothelial cells (HUVECs) was investigated. In the present study, the optimal stimulation conditions for HUVECs were screened for inducing endothelial inflammation, namely, high glucose at the concentration of 30mM for continuous 8h. The endothelial production of high-glucose-induced interleukin (IL)-4, IL-6, IL-13 and signal transducer and activator of transcription-3 (STAT-3) phosphorylation were significantly inhibited by the pretreatment with GA at concentrations of 10, 15 and 20μM based on enzyme-linked immunosorbent assay (ELISA), western blot or/and RT-PCR experiments. These senescent alterations induced by high glucose were significantly attenuated by the specific STAT3 inhibitor S3I-201 at the concentration of 20μM. Furthermore, the phosphorylation of STAT3, IL-4, IL-6, IL-13 and intercellular cell adhesion molecule-1 (ICAM-1) protein as well as mRNA levels were attenuated by the pretreatment of cells with STAT3 siRNA. Our results demonstrated that GA improved high-glucose-caused low-grade vascular inflammation, which might be achieved through regulating the STAT3-mediated pathway. These findings indicated that GA might be a promising candidate for attenuating vascular inflammation in diabetic vascular complications.

Angiotensin II-induced endothelial dysfunction is temporally linked with increases in interleukin-6 and vascular macrophage accumulation

Angiotensin II (Ang II) is associated with vascular hypertrophy, endothelial dysfunction and activation of a number of inflammatory molecules, however the linear events involved in the development of hypertension and endothelial dysfunction produced in response to Ang II are not well defined. The goal of this study was to examine the dose- and temporal-dependent development of endothelial dysfunction in response to Ang II. Blood pressure and responses of carotid arteries were examined in control (C57Bl/6) mice and in mice infused with 50, 100, 200, 400, or 1000 ng/kg/min Ang II for either 14 or 28 Days. Infusion of Ang II was associated with graded and marked increases in systolic blood pressure and plasma Ang II concentrations. While low doses of Ang II (i.e., 50 and 100 ng/kg/min) had little to no effect on blood pressure or endothelial function, high doses of Ang II (e.g., 1000 ng/kg/min) were associated with large increases in arterial pressure and marked impairment of endothelial function. In contrast, intermediate doses of Ang II (200 and 400 ng/kg/min) while initially having no effect on systolic blood pressure were associated with significant increases in pressure over time. Despite increasing blood pressure, 200 ng/kg/min had no effect on endothelial function, whereas 400 ng/kg/min produced modest impairment on Day 14 and marked impairment of endothelial function on Day 28. The degree of endothelial dysfunction produced by 400 and 1000 ng/kg/min Ang II was reflective of parallel increases in plasma IL-6 levels and vascular macrophage content, suggesting that increases in arterial blood pressure precede the development of endothelial dysfunction. These findings are important as they demonstrate that along with increases in arterial pressure that increases in IL-6 and vascular macrophage accumulation correlate with the impairment of endothelial function produced by Ang II.

Protective role of IL-6 in vascular remodeling in Schistosoma pulmonary hypertension

Schistosomiasis is one of the most common causes of pulmonary arterial hypertension worldwide, but the pathogenic mechanism by which the host inflammatory response contributes to vascular remodeling is unknown. We sought to identify signaling pathways that play protective or pathogenic roles in experimental Schistosoma-induced pulmonary vascular disease via whole-lung transcriptome analysis. Wild-type mice were experimentally exposed to Schistosoma mansoni ova by intraperitoneal sensitization followed by tail-vein augmentation, and the phenotype was assessed by right ventricular catheterization and tissue histology, as well as RNA and protein analysis. Whole-lung transcriptome analysis by microarray and RNA sequencing was performed, and RNA sequencing was analyzed according to two bioinformatics methods. Functional testing of the candidate IL-6 pathway was determined using IL-6 knockout mice and the signal transducers and activators of transcription protein-3 (STAT3) inhibitor S3I-201. Wild-type mice exposed to S. mansoni demonstrated increased right ventricular systolic pressure and thickness of the pulmonary vascular media. Whole-lung transcriptome analysis determined that the IL-6-STAT3-nuclear factor of activated T cells c2(NFATc2) pathway was up-regulated, as confirmed by PCR and the immunostaining of lung tissue from S. mansoni-exposed mice and patients who died of the disease. Mice lacking IL-6 or treated with S3I-201 developed pulmonary hypertension, associated with significant intima remodeling after exposure to S. mansoni. Whole-lung transcriptome analysis identified the up-regulation of the IL-6-STAT3-NFATc2 pathway, and IL-6 signaling was found to be protective against Schistosoma-induced intimal remodeling.

Heart failure with preserved ejection fraction: emerging drug strategies

Approximately half of heart failure patients have a normal ejection fraction, a condition designated as heart failure with preserved ejection fraction (HFpEF). This heart failure subtype disproportionately affects women and the elderly and is commonly associated with other cardiovascular comorbidities, such as hypertension and diabetes. HFpEF is increasing at a steady rate and is predicted to become the leading cause of heart failure within a decade. HFpEF is characterized by impaired diastolic function, thought to be due to concentric remodeling of the heart along with increased stiffness of both the extracellular matrix and myofilaments. In addition, oxidative stress and inflammation are thought to have a role in HFpEF progression, along with endothelial dysfunction and impaired nitric oxide-cyclic guanosine monophosphate-protein kinase G signaling. Surprisingly a number of clinical studies have failed to demonstrate any benefit of drugs effective in heart failure with systolic dysfunction in HFpEF patients. Thus, HFpEF is one of the largest unmet needs in cardiovascular medicine, and there is a substantial need for new therapeutic approaches and strategies that target mechanisms specific for HFpEF. This conclusion is underscored by the recently reported disappointing results of the RELAX trial, which assessed the use of phosphodiesterase-5 inhibitor sildenafil for treating HFpEF. In animal models, endothelial nitric oxide synthase activators and If current inhibitors have shown benefit in improving diastolic function, and there is a rationale for assessing matrix metalloproteinase 9 inhibitors and nitroxyl donors. LCZ696, a combination drug of angiotensin II receptor blocker and neprilysin inhibitor, and the aldosterone receptor antagonist spironolactone are currently in clinical trial for treating HFpEF. Here we present an overview of the etiology and diagnosis of HFpEF that segues into a discussion of new therapeutic approaches emerging from basic research and drugs currently in clinical trial that primarily target diastolic dysfunction or imbalanced ventricular-arterial coupling.

Interleukin-10 protects against aging-induced endothelial dysfunction

Carotid and cerebrovascular disease increase markedly with age contributing to stroke and cognitive impairment. Inflammation is a key element of vascular disease. In these studies, we tested the hypothesis that interleukin-10 (IL-10), a potent anti-inflammatory cytokine, protects against aging-induced endothelial dysfunction. Responses of carotid arteries from adult (5 ± 1 months) and old (22 ± 1 months) wild-type and IL-10-deficient mice were examined in vitro. Acetylcholine (an endothelium-dependent agonist) produced relaxation in arteries from adult wild-type that was not altered in old mice. In contrast, relaxation to acetylcholine in arteries from old IL-10-deficient mice was reduced by ∼50% (P < 0.05). Tempol, a scavenger of superoxide, did not affect responses in adult or old wild-type mice, but restored vasodilation to acetylcholine to normal in old IL-10-deficient mice. Responses of the carotid artery to nitroprusside (an endothelium-independent agonist) were not altered in any group. Vascular expression of IL-6 (a proinflammatory mediator of vascular disease) and components of NADPH oxidase (a major source of superoxide) was increased in old IL-10-deficient mice compared with wild-type (P < 0.05). These findings provide the first evidence that age-related and superoxide-mediated endothelial dysfunction occurs earlier with IL-10 deficiency. Our findings suggest a novel role for IL-10 to protect against age-related increases in expression of IL-6, oxidative stress, and endothelial dysfunction.

Protective effects of losartan in mice with chronic viral myocarditis induced by coxsackievirus B3

AIM

To investigate whether losartan has protective effects in mice with chronic viral myocarditis induced by coxsackievirus B3 (CVB3).

MAIN METHODS

Thirty two male Balb/c mice were intraperitoneally injected with CVB3 (10×TCID50) to induce chronic viral myocarditis (CVM). Losartan at 12.5mg/kg (n=16) or normal saline (n=16) were orally administered daily for 28 days to these mice. Uninfected mice (n=6) were used as controls. On day 29, all mice underwent anesthesia and echocardiography prior to sacrifice. Serum IL-17, IL-4, IFN-γ and TNF-α levels were measured by enzyme-linked immunosorbent assay, and cardiac tissues were histologically examined after hematoxylin & eosin staining. In addition, the effect of losartan on the virus titers in primary cultured neonatal rat cardiomyocytes infected with CVB3 was measured on Hep-2 cells at 72 h post infection.

KEY FINDINGS

Mice infected with CBV3 had significantly increased mortality, heart/body weight ratios, necrosis and inflammatory scores and decreased cardiac ejection fractions, compared with the controls (all P<0.05). Losartan significantly decreased mortality from 40.0% to 12.5%, heart/body weight ratios from 7.08 ± 2.17 to 4.15 ± 0.99, and necrosis and inflammatory scores from 3.33 ± 0.50 to 2.50 ± 0.65 (all P<0.05), and increased ejection fractions from 55.80 ± 9.25 to 72.31 ± 12.15 (P<0.05). Losartan significantly enhanced IL-4, and decreased IFN-γ, TNF-α and IL-17 (all P<0.05). In the in vitro experiment, losartan had no influence on virus titers.

SIGNIFICANCE

Losartan protects mice against CVB3-induced CVM, most likely through upregulating Th2 responses, and down-regulating Th1 and Th17 responses.