Ling-Ran Kong

Complement-mediated inhibition of adiponectin regulates perivascular inflammation and vascular injury in hypertension

Perivascular adipose tissue (PVAT)‐derived adiponectin (APN) is a secreted adipokine that protects against hypertension‐related cardiovascular injury. However, the regulation of APN expression in hypertension remains to be explored. In this study, we demonstrated that down‐regulation of APN was associated with complement activation in the PVAT of desoxycorticosterone acetate (DOCA)‐salt hypertensive mice. Complement 3‐deficient hypertensive mice were protected from ANP decrease in the PVAT. APN deficiency blockaded the protective effects of complement inhibition against hypertensive vascular injury. Mechanistically, complement 5a (C5a)‐induced TNF‐α secretion from macrophages is required for inhibiting APN expression in adipocytes. Macrophage depletion reversed C5a agonist peptide‐induced TNF‐α up‐regulation and APN down‐regulation in the PVAT of DOCA mice. Moreover, we detected increased macrophage infiltration and C5a expression associated with decreased APN expression in adipose tissue from patients with aldosterone‐producing adenoma. These results identify a novel interaction between macrophages and adipocytes in the PVAT, where complement‐mediated inhibition of APN acts as a potential risk factor for hypertensive vascular inflammation.—Ruan, C.‐C., Ma, Y., Ge, Q., Li, Y., Zhu, L.‐M., Zhang, Y., Kong, L.‐R., Wu, Q‐H., Li, F., Cheng, L., Zhao, A. Z., Zhu, D.‐L., Gao, P.‐J. Complement‐mediated inhibition of adiponectin regulates perivascular inflammation and vascular injury in hypertension. FASEB J. 31, 1120–1129 (2017). www.fasebj.org

Decrease of Perivascular Adipose Tissue Browning Is Associated With Vascular Dysfunction in Spontaneous Hypertensive Rats During Aging

Functional perivascular adipose tissue (PVAT) is necessary to maintain vascular physiology through both mechanical support and endocrine or paracrine ways. PVAT shows a brown adipose tissue (BAT)-like feature and the browning level of PVAT is dependent on the anatomic location and species. However, it is not clear whether PVAT browning is involved in the vascular tone regulation in spontaneously hypertensive rats (SHRs). In the present study, we aimed to illustrate the effect of aging on PVAT browning and subsequent vasomotor reaction in SHRs. Herein we utilized histological staining and western blot to detect the characteristics of thoracic PVAT (tPVAT) in 8-week-old and 16-week-old SHR and Wistar-Kyoto (WKY) rats. We also detected vascular reactivity analysis to determine the effect of tPVAT on vasomotor reaction during aging. The results showed that tPVAT had a similar phenotype to BAT, including smaller adipocyte size and positive uncoupling protein-1 (UCP1) staining. Interestingly, the tPVAT of 8-week-old SHR showed increased BAT phenotypic marker expression compared to WKY, whereas the browning level of tPVAT had a more dramatic decrease from 8 to 16 weeks of age in SHR than age-matched WKY rats. The vasodilation effect of tPVAT on aortas had no significant difference in 8-week-old WKY and SHR, whereas this effect is obviously decreased in 16-week-old SHR compared to WKY. In contrast, tPVAT showed a similar vasoconstriction effect in 8- or 16-week-old WKY and SHR rats. Moreover, we identified an important vasodilator adenosine, which regulates adipocyte browning and may be a potential PVAT-derived relaxing factor. Adenosine is dramatically decreased from 8 to 16 weeks of age in the tPVAT of SHR. In summary, aging is associated with a decrease of tPVAT browning and adenosine production in SHR rats. These may result in attenuated vasodilation effect of the tPVAT in SHR during aging.

Loss of osteoglycin promotes angiogenesis in limb ischaemia mouse models via modulation of vascular endothelial growth factor and vascular endothelial growth factor receptor 2 signalling pathway

Objective Osteoglycin (OGN) has been noted for its implication in cardiovascular disease in recent studies. However, the relationship between OGN and angiogenesis remains unknown. Therefore, we aimed to investigate the effect of OGN on ischaemia-induced angiogenesis and to address the underlying mechanisms. Methods and results The expression of OGN was decreased in a limb ischaemia mouse model. OGN knockout (KO) mice were used to further understand the role of OGN after ischaemia. The perfusion recovery rate after femoral artery ligation was higher in OGN KO mice than in wild-type (WT) mice. The capillary density in the gastrocnemius muscle of the ischaemic limb was also higher in OGN KO mice. Moreover, ex vivo aortic ring explants from OGN KO mice exhibited stronger angiogenic sprouting than those from WT mice. In human umbilical vein endothelial cells (HUVECs), OGN knockdown enhanced endothelial cell (EC) activation, including tube formation, proliferation, and migration. In contrast, OGN overexpression inhibited HUVEC activation. Mechanistic studies revealed that OGN associates with vascular endothelial growth factor receptor 2 (VEGFR2) and negatively regulates the interaction of vascular endothelial growth factor (VEGF) and VEGFR2, thereby negatively modulating the activation of VEGFR2 and its downstream signalling pathways. Consistently, the pro-angiogenic effect of OGN KO was abrogated by VEGFR2 inhibition, supporting the critical role of VEGFR2 signalling in OGN-mediated regulation of angiogenic function. Conclusions OGN plays a critical role in negatively regulating ischaemia-induced angiogenesis by inhibiting VEGF–VEGFR2 signalling and thereby attenuating EC tube formation, proliferation, and migration. Thus, OGN may be a novel therapeutic target for ischaemic vascular diseases.

Beta3 adrenergic receptor is involved in vascular injury in deoxycorticosterone acetate‐salt hypertensive mice

Beta3 adrenergic receptor (ADRB3) mediates vessel relaxation in the endothelium while it modulates lipolysis in the adipose tissue. However, the function and regulation mechanism of ADRB3 in the perivascular adipose tissue (PVAT), especially in hypertension, is still unclear. We show that ADRB3 protein is upregulated in the PVAT of deoxycorticosterone acetate‐salt (DOCA‐salt) hypertensive mice, with the characteristics of PVAT browning and increased uncoupling protein 1 (UCP1) expression. Inhibition of ADRB3 with selective antagonist SR59230A caused serious vascular injury in vivo, even though UCP1 expression was downregulated. ADRB3 protein was regulated by let‐7b, which was decreased in the PVAT of the DOCA‐salt group. These data reveal that ADRB3 in PVAT contributes to vascular function in the progression of hypertension.

Perivascular Adipose Tissue-Derived PDGF-D Contributes to Aortic Aneurysm Formation during Obesity

Obesity increases the risk of vascular diseases, including aortic aneurysm (AA). Perivascular adipose tissue (PVAT) surrounding arteries are altered during obesity. However, the underlying mechanism of adipose tissue, especially PVAT, in the pathogenesis of AA is still unclear. Here we showed that angiotensin II (AngII) infusion increases the incidence of AA in leptin-deficient obese mice (ob/ob) and high-fat diet–induced obese mice with adventitial inflammation. Furthermore, transcriptome analysis revealed that platelet-derived growth factor-D (PDGF-D) was highly expressed in the PVAT of ob/ob mice. Therefore, we hypothesized that PDGF-D mediates adventitial inflammation, which provides a direct link between PVAT dysfunction and AA formation in AngII-infused obese mice. We found that PDGF-D promotes the proliferation, migration, and inflammatory factors expression in cultured adventitial fibroblasts. In addition, the inhibition of PDGF-D function significantly reduced the incidence of AA in AngII-infused obese mice. More importantly, adipocyte-specific PDGF-D transgenic mice are more susceptible to AA formation after AngII infusion accompanied by exaggerated adventitial inflammatory and fibrotic responses. Collectively, our findings reveal a notable role of PDGF-D in the AA formation during obesity, and modulation of this cytokine might be an exploitable treatment strategy for the condition.

A2A Receptor Activation Attenuates Hypertensive Cardiac Remodeling via Promoting Brown Adipose Tissue-Derived FGF21

Adipocytes play important roles in regulating cardiovascular health and disease. However, the molecular mechanism underlying the endocrine role of brown adipose tissue (BAT) in pathological cardiac remodeling remains unknown. Herein we show that adenosine A2A receptor (A2AR) knockout (A2ARKO) causes interscapular BAT (iBAT) dysfunction, leading to accelerated cardiac remodeling in hypertension compared with wild-type (WT) mice. Surgical iBAT depletion induces dramatic cardiac remodeling in WT but not in A2ARKO hypertensive mice. AMPK/PGC1α signaling-induced fibroblast growth factor 21 (FGF21) in brown adipocytes is required for A2AR-mediated inhibition of hypertensive cardiac remodeling. Recombinant FGF21 administration improves cardiac remodeling in iBAT-depleted hypertensive mice. More importantly, brown adipocyte-specific A2ARKO inhibits FGF21 production and accelerates cardiac damage in hypertension. Consistently, brown adipocyte-specific FGF21 knockout abolishes the effects of A2AR agonism in attenuating hypertensive cardiac remodeling. Our findings reveal a distinctive endocrine role of BAT in hypertensive cardiac remodeling via activating A2AR/FGF21 pathway.

Complement 5a-mediated trophoblasts dysfunction is involved in the development of pre-eclampsia

Pre‐eclampsia (PE) is a life‐threatening multisystem disorder leading to maternal and neonatal mortality and morbidity. Emerging evidence showed that activation of the complement system is implicated in the pathological processes of PE. However, little is known about the detailed cellular and molecular mechanism of complement activation in the development of PE. In this study, we reported that complement 5a (C5a) plays a pivotal role in aberrant placentation, which is essential for the onset of PE. We detected an elevated C5a deposition in macrophages and C5a receptor (C5aR) expression in trophoblasts of pre‐eclamptic placentas. Further study showed that C5a stimulated trophoblasts towards an anti‐angiogenic phenotype by mediating the imbalance of angiogenic factors such as soluble fms‐like tyrosine kinase 1 (sFlt1) and placental growth factor (PIGF). Additionally, C5a inhibited the migration and tube formation of trophoblasts, while, C5aR knockdown with siRNA rescued migration and tube formation abilities. We also found that maternal C5a serum level was increased in women with PE and was positively correlated with maternal blood pressure and arterial stiffness. These results demonstrated that the placental C5a/C5aR pathway contributed to the development of PE by regulating placental trophoblasts dysfunctions, suggesting that C5a may be a novel therapeutic possibility for the disease.

OS 23-02 THE ROLE OF COMPLEMENT C5a-MEDIATED PLACENTAL DYSFUNCTION IN THE ONSET OF PREECLAMPSIA.

Objective: Women with preeclampsia (PE) display excessive activation of complement system. However, little is known about the detailed cellular and molecular mechanism of complement activation in the development of PE. Here, we hypothesized that whether complement C5a contributes to the onset of PE through its effect on trophoblasts. Design and Method: In this study, 23 women with established PE and 32 normotensive women were recruited. At entry, peripheral and central blood pressure and pulse wave velocity (PWV) were performed. Immunofluorescence and quantitative real-time PCR were performed to identify the expression of C5a in the placenta. Transwell and matrigel assay was conducted to assess the effect of C5a on invasion and angiogenesis of human trophoblast cell lines. The serum level of C5a was measured by ELISA. Results: We detected an elevated C5a deposition in the placenta of patients with PE and C5aR was found highly expressed in syncytiotrophoblasts. In cultured trophoblast cell lines, C5aR agonist peptide inhibited the migration and angiogenesis of trophoblasts. C5aR agonist peptide stimulation also resulted in increased anti-angiogenic factors but decreased pro-angiogenic factors. In maternal circulation, the concentration of C5a was higher in women with PE compared to normotensive women (99.75 ± 29.27 ng/ml vs 76.35 ± 16.97 ng/ml mean ± SD P < 0.01). And meanwhile C5a has positive correlation with systolic blood pressure (r = 0.371, P < 0.01) and diastolic blood pressure (r = 0.343, P < 0.05). Women with PE displayed poor arterial function, which was also positively correlated with C5a level. Conclusions: Our data suggest that C5a contributed to the dysfunction of placenta by inhibition of migration and angiogenesis of trophoblast cells via C5aR in parallel with increase of blood pressure and arterial stiffness. The results indicate that C5a may have a novel role as a mediator of pathogenesis of PE, which could potentially result in gestational vascular dysfunction.

[OP.8C.05] A2A RECEPTOR-MEDIATED ACTIVATION OF REGULATORY T CELLS ATTENUATES HYPERTENSION-INDUCED CARDIORENAL CONSEQUENCE

Objective: Inflammatory processes plays a pivotal role in pathogenesis of hypertension. Previous study have indicated that A2A receptor is closely related with immunogenic anti-inflammation process. The present study aimed to elucidate whether the activation of A2A receptor is involved in the regulation of hypertension-induced cardiovascular consequence via regulating immunoresponse. Design and method: Deoxycorticosterone acetat (DOCA)-salt hypertensive mice were injected intraperitoneally with specific A2A receptor agonist (CGS21680) or antagonist (istradefylline) or PBS respectively. Fourteen days after DOCA-salt infusion, the expressional diversity of immune-related cytokines and chemokines were detected by quantitative real time PCR and western blot. Flow cytometric analysis was used to assess spleen CD4+, CD8+ and Foxp3+ T cells. The cardiovascular function of DOCA-salt mice was detected by wire myography and echocardiography. Results: The treatment of CGS21680 resulted in an dramatically increase of regulatory T cells (Tregs,CD4+Foxp3+) in spleen, accompanied by the increased volume and weight of spleen (Figure), while istradefylline accelerated DOCA-salt induced hypertension inflammation. CGS21680 stimulation also resulted in decreased inflammatory cytokins level as IL-6 and MCP1 in heart and renal. Relax function of aorta significantly elevated in CGS21680-treated DOCA-salt mice and the echocardiographic results display an obvious improvement of cardiovascular functions. Figure. No caption available. Conclusions: These datas indicate that CGS21680 acts through A2A receptor to increase regulatory T cells, causing the attenuation of hypertension-induced cardiovascular injury. Overall, A2A receptor may be a novel role in hypertension therapeutic strategy.

OS 36-08 A2A RECEPTOR-MEDIATED ACTIVATION OF REGULATORY T CELLS ATTENUATES HYPERTENSION-INDUCED CARDIOVASCULAR INJURY.

Objective: Inflammatory processes plays a pivotal role in pathogenesis of hypertension. Previous study have indicated that A2A receptor is closely related with immunogenic anti-inflammation process. The present study aimed to elucidate whether the activation of A2A receptor is involved in the regulation of hypertension-induced cardiovascular consequence via regulating immunoresponse. Design and Method: Deoxycorticosterone acetat (DOCA)-salt hypertensive mice were injected intraperitoneally with specific A2A receptor agonist (CGS21680) or antagonist (istradefylline) or PBS respectively. Fourteen days after DOCA-salt infusion, the expressional diversity of immune-related cytokines and chemokines were detected by quantitative real time PCR and western blot. Flow cytometric analysis was used to assess spleen CD4+, CD8+ and Foxp3+ T cells. The cardiovascular function of DOCA-salt mice was detected by wire myography and echocardiography. Results: The treatment of CGS21680 resulted in a dramatically increase of regulatory T cells (Tregs,CD4+Foxp3+) in spleen, accompanied by the increased volume and weight of spleen (Figure), while istradefylline accelerated DOCA-salt induced hypertension inflammation. CGS21680 stimulation also resulted in decreased inflammatory cytokins level as IL-1&bgr;, IL-6 and MCP1 in heart. Relax function of aorta significantly elevated in CGS21680-treated DOCA-salt mice and the echocardiographic results display an obvious improvement of cardiovascular functions. Conclusions: These data indicates that CGS21680 acts through A2A receptor to increase regulatory T cells, causing the attenuation of hypertension-induced cardiovascular injury. Overall, A2A receptor may be a novel role in hypertension therapeutic strategy. Figure. No caption available.