Abstract 14820: Sirt7 Deficiency in Blood Vessel Components Impairs Vascular Function by Inhibiting Cell Cycle- and Inflammatory-Related Protein Expression

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Yuichi Kimura ◽  
Yasuhiro Izumiya ◽  
Satoshi Araki ◽  
Satoru Yamamura ◽  
Yoshiro Onoue ◽  
...  

Introduction: Aging is a well-established cardiovascular risk factor and associated with vascular dysfunction. Sirt7, one of the members of mammalian sirtuin family, is thought to be involved in age-related diseases. However, little is known about the relative contribution of Sirt7 in vascular dysfunction. Hypothesis: Sirt7 maintains vascular cell functions and its deficiency plays a critical role in vascular diseases. Methods: Sirt7 loss- and gain-of-function experiments were performed with human aortic smooth muscle cells (HAoSMCs) and human umbilical vein endothelial cells (HUVECs). In vivo, blood flow recovery was evaluated by hindlimb ischemia model in homozygous Sirt7 deficient (Sirt7-/-) and wild-type (WT) mice. Irradiated WT mice were intravenously received bone marrow (BM) cells from WT or Sirt7 -/- mouse to achieve BM transfer. Results: An RNAi-medicated Sirt7 knockdown resulted in a significant inhibition of HAoSMCs proliferation following serum or Platelet-derived growth factor BB (PDGF-BB) stimulation as determined by cell count, BrdU cell proliferation assay and MTS proliferation assay. Knockdown of endogenous Sirt7 also reduced cell migration as revealed by Boyden chamber migration assay. The Cyclin D1 and Cyclin dependent kinase 2 (CDK2) protein levels were significantly decreased in Sirt7 siRNA-treated HAoSMCs in response to serum or PDGF-BB stimulation. In endothelial cells, knockdown of Sirt7 attenuated tube formation, proliferation and migration. These changes were accompanied by reduced ERK activation and VCAM-1 mRNA and protein expression in Sirt7 siRNA-treated HUVECs. Conversely, overexpression of Sirt7 by adenovirus enhanced tube formation and cell proliferation. In vivo, blood flow recovery in response to hindlimb ischemia was significantly attenuated in Sirt7-/- mice compared with WT mice. There was no difference in blood flow recovery between WT mice transplanted with WT or Sirt7-/- BM cells suggesting that Sirt7 deficiency in vascular cells have a predominant effect on attenuated blood flow recovery in response to hindlimb ischemia. Conclusions: Sirt7 in blood vessel components have an important role in maintenance of vascular function. Sirt7 could be a promising therapeutic target for vascular diseases.

2021 ◽  
Author(s):  
Maria Sancho ◽  
Nicholas R. Klug ◽  
Amreen Mughal ◽  
Thomas J. Heppner ◽  
David Hill-Eubanks ◽  
...  

SUMMARYThe dense network of capillaries composed of capillary endothelial cells (cECs) and pericytes lies in close proximity to all neurons, ideally positioning it to sense neuro/glial-derived compounds that regulate regional and global cerebral perfusion. The membrane potential (VM) of vascular cells serves as the essential output in this scenario, linking brain activity to vascular function. The ATP-sensitive K+ channel (KATP) is a key regulator of vascular VM in other beds, but whether brain capillaries possess functional KATP channels remains unknown. Here, we demonstrate that brain capillary ECs and pericytes express KATP channels that robustly control VM. We further show that the endogenous mediator adenosine acts through A2A receptors and the Gs/cAMP/PKA pathway to activate capillary KATP channels. Moreover, KATP channel stimulation in vivo causes vasodilation and increases cerebral blood flow (CBF). These findings establish the presence of KATP channels in cECs and pericytes and suggest their significant influence on CBF.HIGHLIGHTSCapillary network cellular components—endothelial cells and pericytes—possess functional KATP channels.Activation of KATP channels causes profound hyperpolarization of capillary cell membranes.Capillary KATP channels are activated by exogenous adenosine via A2A receptors and cAMP-dependent protein kinase.KATP channel activation by adenosine or synthetic openers increases cerebral blood flow.


2019 ◽  
Author(s):  
Qian Zhang ◽  
Tao Wang ◽  
Xiangfeng Wu ◽  
Ying Wang ◽  
Xuanqin Wu ◽  
...  

Abstract Background: Critical limb ischemia (CLI) is the leading cause of lower limb amputation. Traditional treatments for CLI have limitations. Studies have shown that thrombospondin-4 (TSP4) can promote the growth of neovascularization. Results: In this study, we observed the angiogenesis efficiency of TSP4-overexpressing BMSC transplantation in CLI treatment. The recombinant FT106-tsp4-gfp lentiviral vector plasmid was constructed and transfected into 293FT cells. Primary BMSCs were successfully infected with the tsp4 virus, and TSP4 overexpression was confirmed before TSP4-BMSCs infusion. In vitro, TSP4-BMSCs were co-cultured with human umbilical vein endothelial cells (HUVECs). Vascular endothelial growth factor (VEGF) and transforming growth factor-β (TGF-β) secretion were measured in the co-culture supernatants by ELISA. The effect of TSP4-BMSCs on endothelial cell proliferation and migration was detected. Meanwhile, the effects of TSP4-BMSC on the angiogenesis of endothelial cells were tested by tube formation experiment and arterial ring test. In vivo, a rat CLI model was established, and 60 CLI rats were randomly divided into the CLI, BMSC + CLI and TSP4-BMSC + CLI groups. The effect of TSP4-BMSC on angiogenesis was detected by the motor function, immunohistochemistry and immunofluorescence staining assays. Neovascular density was detected by digital substraction angiography (DSA). Our results demonstrated that TSP4-BMSCs obviously increased TSP4, VEGF, Ang-1, MMP9, MMP2 and p-Cdc42/Rac1 expression in endothelial cells. TSP4-BMSCs treatment notably upregulated the TGF-β/smad2/3 signal pathway in HUVECs. In vivo, TSP4-BMSCs improved the motor function score of the CLI rats and increased MMP2, MMP9, Ang-1, VEGF and vWF protein expression in tissue of the ischaemic area. Meanwhile, new blood vessels can be observed around the ischemic area after TSP4-BMSCs treatment. Conclusion: Our data illustrate that TSP4-BMSCs can promote endothelial cell proliferation, migration, tube formation and the recovery of motor function in diabetic hind limb ischaemic rats. TSP4-BMSCs have better therapeutic effects than BMSCs.


2020 ◽  
Author(s):  
Qian Zhang ◽  
Tao Wang ◽  
Xiangfeng Wu ◽  
Ying Wang ◽  
Xuanqin Wu ◽  
...  

Abstract Background Critical limb ischemia (CLI) is the leading cause of lower limb amputation. Traditional treatments for CLI have limitations. Studies have shown that thrombospondin-4 (TSP4) can promote the growth of neovascularization. In this study, we observed the angiogenesis efficiency of TSP4-overexpressing BMSC transplantation in CLI treatment. Methods The recombinant FT106-tsp4-gfp lentiviral vector plasmid was constructed and transfected into 293FT cells. Primary BMSCs were successfully infected with the tsp4 virus, and TSP4 overexpression was confirmed before TSP4-BMSCs infusion. In vitro, TSP4-BMSCs were co-cultured with human umbilical vein endothelial cells (HUVECs). Vascular endothelial growth factor (VEGF) and transforming growth factor-β (TGF-β) secretion were measured in the co-culture supernatants by ELISA. The effect of TSP4-BMSCs on endothelial cell proliferation and migration was detected. Meanwhile, the effects of TSP4-BMSC on the angiogenesis of endothelial cells were tested by tube formation experiment and arterial ring test. In vivo, a rat CLI model was established, and 60 CLI rats were randomly divided into the CLI, BMSC + CLI and TSP4-BMSC + CLI groups. The effect of TSP4-BMSC on angiogenesis was detected by the motor function, immunohistochemistry and immunofluorescence staining assays. Neovascular density was detected by digital substraction angiography (DSA). Results Our results demonstrated that TSP4-BMSCs obviously increased TSP4, VEGF, Ang-1, MMP9, MMP2 and p-Cdc42/Rac1 expression in endothelial cells. TSP4-BMSCs treatment notably upregulated the TGF-β/smad2/3 signal pathway in HUVECs. In vivo, TSP4-BMSCs improved the motor function score of the CLI rats and increased MMP2, MMP9, Ang-1, VEGF and vWF protein expression in tissue of the ischaemic area. Meanwhile, new blood vessels can be observed around the ischemic area after TSP4-BMSCs treatment. Conclusions Our data illustrate that TSP4-BMSCs can promote endothelial cell proliferation, migration, tube formation and the recovery of motor function in diabetic hind limb ischaemic rats. TSP4-BMSCs have better therapeutic effects than BMSCs.


Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Gregory A Payne ◽  
Lena Borbouse ◽  
Gregory M Dick ◽  
Johnathan D Tune

Adipocytokines may be the molecular link between obesity and vascular disease; however, effects of these factors on coronary vascular function have not been delineated. Accordingly, this study was designed to examine mechanisms by which endogenous adipocyte-derived factors impair coronary endothelial-dependent vasodilation in vivo . Experiments were conducted in open-chest anesthetized dogs (n = 16) before and during treatment with endogenous adipocyte-derived factors. Phosphate buffered saline was conditioned in a shaking water bath with parietal pericardial adipose tissue (3 g/ml) for 30 min at 37°C. The conditioned buffer was then filtered (0.2 μm) and infused directly into the coronary circulation (0.3 ml/min). Conditioned buffer did not significantly affect baseline coronary blood flow (0.50 ± 0.01 vs. 0.61 ± 0.05 ml/min/g, p = 0.68), mean arterial pressure (103 ± 6 vs. 96 ± 9 mmHg, p = 0.74), or heart rate (87 ± 13 vs. 110 ± 24 beats/min, p = 0.44). Conditioned buffer had no effect on responses to intracoronary angiotensin II (2.5 – 750 ng; 74 vs. 70% vasoconstriction). Under control conditions, bradykinin (0.03 – 3 μg/min) increased coronary blood flow (303 ± 65%) to 2.02 ± 0.31 ml/min/g in a dose-dependent manner. Conditioned buffer attenuated maximum bradykinin vasodilation to 1.64 ± 0.26 ml/min/g (167 ± 33% increase; p < 0.05). This decrease in endothelial-dependent dilation was not due to increases in superoxide production, as administration of the superoxide dismutase mimetic Tempol (10 mg/min, ic) did not improve bradykinin vasodilation (120 ± 27% increase; p < 0.05). Inhibition of nitric oxide synthase with L-NAME (150 μg/min, ic) reduced maximum bradykinin vasodilation to 0.93 ± 0.04 ml/min/g (p < 0.05) and endogenous adipocyte-derived factors had no further inhibitory effect (0.82 ± 0.09 ml/min/g, p = 0.24). These data indicate that endogenous adipocyte-derived factors diminish endothelial-dependent coronary vasodilation via inhibition of nitric oxide synthase rather than a reduction in nitric oxide bioavailability by superoxide. Our findings importantly link endogenous adipocyte-derived factors with pro-atherogenic coronary vascular dysfunction in vivo .


2018 ◽  
Vol 48 (5) ◽  
pp. 2114-2122
Author(s):  
Hairong Xu ◽  
Shan Lu ◽  
Lexi Ding ◽  
Liangkun Lyu ◽  
Zejun Ma ◽  
...  

Background/Aims: In clinical settings, the pulsatility index (PI) has become a widely used tool for monitoring obstetrics or other vascular diseases. It is based on the maximum Doppler shift waveform derived from ultrasonography. However, it remains unclear whether the PI levels are correctly predicted from the perfusion in mouse model of hindlimb ischemia. Methods: To explore the relationship between PI and perfusion, we generated a unilateral hindlimb ischemia model in 8-week-old C57BL/6 male mice by ligation of the right common iliac artery and femoral artery. These mice were monitored with laser Doppler perfusion imaging (LDPI) and an ultrasound system (Vevo2100). Vessel densities in ischemic skeletal muscles were measured with vWF staining, which functions as a marker for endothelial cells. In order to further verify PI evaluation in other conditions, we performed therapeutic experiments using hindlimb ischemic mouse with PBS or FGF2 treatment. Results: In the mouse model of hindlimb ischemia, the PI levels were continuously elevated and were accompanied by an increased ratio of perfusion to blood flow. 1 and 4 weeks after ischemia, the densities of vWF staining were correlated with PI values. Moreover, the PI index exactly reflected the perfusion in hindlimb ischemic mice after FGF2 treatment, while it indicated the condition of angiogenesis after therapeutic treatment based on the association between PI values and the number of vWF-positive stained cells in muscles. Conclusion: This study confirms the utility of a noninvasive and reproducible ultrasound index for a rapid evaluation of perfusion and blood recovery after hindlimb ischemia in vivo. PI, as one stable and comparable parameter, is correlated with angiogenesis in hindlimb ischemic mouse. Moreover, PI can exactly reflect perfusion and angiogenesis in therapeutic hindlimb ischemic mouse models. This study suggested that PI can serve as a novel index for relatively reproducible and repeatable blood flow recovery in the evaluation of emerging ischemic therapies and disease development in mouse models of hindlimb ischemia.


2016 ◽  
Vol 214 (7) ◽  
pp. 793-795 ◽  
Author(s):  
Claudio A. Franco ◽  
Holger Gerhardt

Bone morphogenic proteins (BMPs) and blood flow regulate vascular remodeling and homeostasis. In this issue, Baeyens et al. (2016. J. Cell Biol. http://dx.doi.org/10.1083/jcb.201603106) show that blood flow sensitizes endothelial cells to BMP9 signaling by triggering Alk1/ENG complexing to suppress cell proliferation and to recruit mural cells, thereby establishing endothelial quiescence.


1995 ◽  
Vol 108 (12) ◽  
pp. 3685-3694 ◽  
Author(s):  
D.S. Grant ◽  
J.L. Kinsella ◽  
M.C. Kibbey ◽  
S. LaFlamme ◽  
P.D. Burbelo ◽  
...  

We performed differential cDNA hybridization using RNA from endothelial cells cultured for 4 hours on either plastic or basement membrane matrix (Matrigel), and identified early genes induced during the morphological differentiation into capillary-like tubes. The mRNA for one clone, thymosin beta 4, was increased 5-fold. Immunostaining localized thymosin beta 4 in vivo in both growing and mature vessels as well as in other tissues. Endothelial cells transfected with thymosin beta 4 showed an increased rate of attachment and spreading on matrix components, and an accelerated rate of tube formation on Matrigel. An antisense oligo to thymosin beta 4 inhibited tube formation on Matrigel. The results suggest that thymosin beta 4 is induced and likely involved in differentiating endothelial cells. Thymosin beta 4 may play a role in vessel formation in vivo.


2014 ◽  
Vol 34 (suppl_1) ◽  
Author(s):  
Sangho Lee ◽  
Min Kyung Lee ◽  
Hyunjoon Kong ◽  
Young-sup Yoon

Various hydrogels are used to create vascular structure in vitro or to improve cell engraftment to overcome low cell survival in vivo, a main hurdle for bare cell therapy Recently we developed a modified alginate hydrogel within which microchannels are aligned to guide the direction and spatial organization of loaded cells. We investigated whether these cell constructs in which HUVECs and human mesenchymal stem cells (hMSCs) are co-loaded in this novel microchanneled hydrogel facilitate formation of vessels in vitro and in vivo, and enhance recovery of hindlimb ischemia. We crafted a modified alginate hydrogel which has microchannels, incorporates a cell adhesion peptide RGD, and was encapsulated with VEGF. We then compared vascular structure formation between the HUVEC only (2 x 105 cells) group and the HUVEC plus hMSC group. In the HUVEC+hMSC group, we mixed HUVECs and hMSCs at the ratio of 3:1. For cell tracking, we labeled HUVECs with DiO, a green fluorescence dye. After loading cells into the microchannels of the hydrogel, these constructs were cultured for seven days and were examined by confocal microscopy. In the HUVEC only group, HUVECs stands as round shaped cells without forming tubular structures within the hydrogel. However, in the HUVEC+hMSC group, HUVECs were stretched out and connected with each other, and formed vessel-like structure following pre-designed microchannels. These results suggested that hMSCs play a critical role for vessel formation by HUVECs. We next determined their in vivo effects using a mouse hindlimb ischemia model. We found that engineered HUVEC+hMSC group showed significantly higher perfusion over 4 weeks compared to the engineered HUVEC only group or bare cell (HUVEC) group. Confocal microscopic analysis of harvested tissues showed more robust vessel formation within and outside of the cell constructs and longer term cell survival in HUVEC+hMSC group compared to the other groups. In conclusion, this novel microchanneled alginate hydrogel facilitates aligned vessel formation of endothelial cells when combined with MSCs. This vessel-embedded hydrogel constructs consisting of HUVECs and MSCs contribute to perfusable vessel formation, prolong cell survival in vivo, and are effective for recovering limb ischemia.


2011 ◽  
Vol 110 (3) ◽  
pp. 695-704 ◽  
Author(s):  
Danielle J. McCullough ◽  
Robert T. Davis ◽  
James M. Dominguez ◽  
John N. Stabley ◽  
Christian S. Bruells ◽  
...  

With advancing age, there is a reduction in exercise tolerance, resulting, in part, from a perturbed ability to match O2 delivery to uptake within skeletal muscle. In the spinotrapezius muscle (which is not recruited during incline treadmill running) of aged rats, we tested the hypotheses that exercise training will 1) improve the matching of O2 delivery to O2 uptake, evidenced through improved microvascular Po2 (PmO2), at rest and throughout the contractions transient; and 2) enhance endothelium-dependent vasodilation in first-order arterioles. Young (Y, ∼6 mo) and aged (O, >24 mo) Fischer 344 rats were assigned to control sedentary (YSED; n = 16, and OSED; n = 15) or exercise-trained (YET; n = 14, and OET; n = 13) groups. Spinotrapezius blood flow (via radiolabeled microspheres) was measured at rest and during exercise. Phosphorescence quenching was used to quantify PmO2 in vivo at rest and across the rest-to-twitch contraction (1 Hz, 5 min) transition in the spinotrapezius muscle. In a follow-up study, vasomotor responses to endothelium-dependent (acetylcholine) and -independent (sodium nitroprusside) stimuli were investigated in vitro. Blood flow to the spinotrapezius did not increase above resting values during exercise in either young or aged groups. Exercise training increased the precontraction baseline PmO2 (OET 37.5 ± 3.9 vs. OSED 24.7 ± 3.6 Torr, P < 0.05); the end-contracting PmO2 and the time-delay before PmO2 fell in the aged group but did not affect these values in the young. Exercise training improved maximal vasodilation in aged rats to acetylcholine (OET 62 ± 16 vs. OSED 27 ± 16%) and to sodium nitroprusside in both young and aged rats. Endurance training of aged rats enhances the PmO2 in a nonrecruited skeletal muscle and is associated with improved vascular smooth muscle function. These data support the notion that improvements in vascular function with exercise training are not isolated to the recruited muscle.


2005 ◽  
Vol 289 (2) ◽  
pp. H916-H923 ◽  
Author(s):  
Nelson N. Orie ◽  
Patrick Vallance ◽  
Dean P. Jones ◽  
Kevin P. Moore

It is now established that S-nitroso-albumin (SNO-albumin) circulates at low nanomolar concentrations under physiological conditions, but concentrations may increase to micromolar levels during disease states (e.g., cirrhosis or endotoxemia). This study tested the hypothesis that high concentrations of SNO-albumin observed in some diseases modulate vascular function and that it acts as a stable reservoir of nitric oxide (NO), releasing this molecule when the concentrations of low-molecular-weight thiols are increased. SNO-albumin was infused into rats to increase the plasma concentration from <50 nmol/l to ∼4 μmol/l. This caused a 29 ± 6% drop in blood pressure, 20 ± 4% decrease in aortic blood flow, and a 25 ± 14% reduction of renal blood flow within 10 min. These observations were in striking contrast to those of an infused arterial vasodilator (hydralazine), which increased aortic blood flow, and suggested that SNO-albumin acts primarily as a venodilator in vivo. This was confirmed by the observations that glyceryl trinitrate (a venodilator) led to similar hemodynamic changes and that the hemodynamic effects of SNO-albumin are reversed by infusion of colloid. Infusion of N-acetylcysteine into animals with artificially elevated plasma SNO-albumin concentrations led to the rapid decomposition of SNO-albumin in vivo and reproduced the hemodynamic effects of SNO-albumin infusion. These data demonstrate that SNO-albumin acts primarily as a venodilator in vivo and represents a stable reservoir of NO that can release NO when the concentrations of low-molecular-weight thiols are elevated.


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