Infused juice concentrate of Japanese plum Prunus mume attenuates inflammatory vascular remodeling in a mouse model of hypertension induced by angiotensin II

Fruit from the Prunus mume tree is a traditional food in Japan. Recently, bainiku-ekisu, an infused juice concentrate of Japanese Prunus mume, is attracting attention as a health promoting supplement. Angiotensin II (Ang II) plays a central role in development of hypertension. It has been reported that bainiku-ekisu treatment attenuates the growth-promoting signaling induced by Ang II in vascular smooth muscle cells. However, whether bainiku-ekisu has any effect on an animal model of hypertension remains unknown. Therefore, this study was designed to explore the potential anti-hypertensive benefit of bainiku-ekisu utilizing a mouse model of hypertension with Ang II infusion. Male C57BL/6 mice were infused with Ang II for 2 weeks and given 0.1% bainiku-ekisu containing water or normal water for 2 weeks with blood pressure evaluation. After 2 weeks, mice were euthanized, and the aortas were collected for evaluation of remodeling. Aortic medial hypertrophy was observed in control mice after Ang II infusion, which was attenuated in bainiku-ekisu group with Ang II infusion. Bainiku-ekisu further attenuated aortic induction of collagen producing cells and immune cell infiltration. Development of hypertension induced by Ang II was also prevented by bainiku-ekisu. Echocardiograph indicated protection of Ang II-induced cardiac hypertrophy by bainiku-ekisu. In vascular fibroblasts, bainiku-ekisu attenuated vascular cell adhesion molecule-1 induction, an endoplasmic reticulum stress marker, inositol requiring enzyme-1α phosphorylation, and enhancement in glucose consumption in response to Ang II. In conclusion, Bainiku-ekisu prevented Ang II-induced hypertension and inflammatory vascular remodeling. Potential cardiovascular health benefit to taking bainiku-ekisu should be further studied.

Angiotensin II Type 1A Receptor Expressed in Smooth Muscle Cells is Required for Hypertensive Vascular Remodeling in Mice Infused With Angiotensin II

BACKGROUND

Ang II (angiotensin II) type 1 (AT1) receptors play a critical role in cardiovascular diseases such as hypertension. Rodents have 2 types of AT1 receptor (AT1A and AT1B) of which knock-in Tagln-mediated smooth muscle AT1A silencing attenuated Ang II-induced hypertension. Although vascular remodeling, a significant contributor to organ damage, occurs concurrently with hypertension in Ang II-infused mice, the contribution of smooth muscle AT1A in this process remains unexplored. Accordingly, it is hypothesized that smooth muscle AT1A receptors exclusively contribute to both medial thickening and adventitial fibrosis regardless of the presence of hypertension.

METHODS

About 1 µg/kg per minute Ang II was infused for 2 weeks in 2 distinct AT1A receptor silenced mice, knock-in Tagln-mediated constitutive smooth muscle AT1A receptor silenced mice, and Myh11-mediated inducible smooth muscle AT1A together with global AT1B silenced mice for evaluation of hypertensive cardiovascular remodeling.

RESULTS

Medial thickness, adventitial collagen deposition, and immune cell infiltration in aorta were increased in control mice but not in both smooth muscle AT1A receptor silenced mice. Coronary arterial perivascular fibrosis in response to Ang II infusion was also attenuated in both AT1A receptor silenced mice. Ang II-induced cardiac hypertrophy was attenuated in constitutive smooth muscle AT1A receptor silenced mice. However, Ang II-induced cardiac hypertrophy and hypertension were not altered in inducible smooth muscle AT1A receptor silenced mice.

CONCLUSIONS

Smooth muscle AT1A receptors mediate Ang II-induced vascular remodeling including medial hypertrophy and inflammatory perivascular fibrosis regardless of the presence of hypertension. Our data suggest an independent etiology of blood pressure elevation and hypertensive vascular remodeling in response to Ang II.

Abstract 320: Glucose Consumption In Vascular Cell Types In Response To Angiotensin Ii

Any experimental outcomes are potentially influenced by extracellular glucose availability and its cellular metabolism in cell culture. However, surveillance of vascular-related journals for the past 5 years demonstrated that less than 20% of articles declared the medium glucose concentration. The present studies were designed to seek ideal medium glucose concentration(s) in vascular cell types with particular attention paid to changes in glucose consumption upon angiotensin II (AngII) stimulation. We have compared glucose consumption in three vascular cell types, endothelial cells (EC), vascular smooth muscle cells (VSMC) and adventitial fibroblasts (AF) with or without 100 nM AngII stimulation. In all cell types after a 48-hour incubation in relatively low glucose media (1 g/L in 6 well dish with 1mL), medium glucose concentration was reduced to almost 0. Whereas medium glucose concentration remained significantly higher (EC 2.77±0.05 g/L, VSMC 3.87±0.05 g/L, AF 3.32±0.01 g/L) when cells were incubated for 48 hours in high glucose (4.5 g/L) media. In middle glucose (2.75 g/L) media, medium glucose concentration remained in physiological ranges (EC 0.62±0.18 g/L, VSMC 1.98±0.07 g/L, AF 1.17±0.17 g/L). AngII treatment enhanced glucose consumption in AF and VSMC but not in EC. Enhanced extracellular acidification rate by AngII was observed in AF. PDGF-BB also stimulated glucose consumption in AF which was associated with a trend of cell proliferation. In AF, AngII induction of target proteins at 48 hours varied depending on the glucose concentration used. In low glucose media induction of GRP78 or hexokinase II was highest, whereas induction of VCAM-1 was lowest. Utilization of specific inhibitors further suggest essential roles of AT1 receptor and glycolysis in AngII-induced fibroblast activation. Overall, the present study demonstrates a high risk of hypo- or hyperglycemic conditions when standard low or high glucose media is used with vascular cells. Moreover, these conditions may significantly alter experimental outcomes. Medium glucose concentration should be monitored during any culture experiments and utilization of middle glucose media is recommended for all vascular cell types.

Glucose consumption of vascular cell types in culture: toward optimization of experimental conditions

In this study, we have looked for an optimum media glucose concentration and compared glucose consumption in three vascular cell types, endothelial cells (ECs), vascular smooth muscle cells (VSMCs), and adventitial fibroblasts (AFs) with or without angiotensin II (AngII) stimulation. In a subconfluent 6-well experiment in 1 mL DMEM with a standard low (100 mg/dL), a standard high (450 mg/dL), or a mixed middle (275 mg/dL) glucose concentration, steady and significant glucose consumption was observed in all cell types. After 48-h incubation, media that contained low glucose was reduced to almost 0 mg/dL, media that contained high glucose remained significantly higher at ∼275 mg/dL, and media that contained middle glucose remained closer to physiological range. AngII treatment enhanced glucose consumption in AFs and VSMCs but not in ECs. Enhanced extracellular acidification rate by AngII was also observed in AFs. In AFs, AngII induction of target proteins at 48 h varied depending on the glucose concentration used. In low glucose media, induction of glucose regulatory protein 78 or hexokinase II was highest, whereas induction of VCAM-1 was lowest. Utilization of specific inhibitors further suggests essential roles of angiotensin II type-1 receptor and glycolysis in AngII-induced fibroblast activation. Overall, this study demonstrates a high risk of hypo- or hyperglycemic conditions when standard low or high glucose media is used with vascular cells. Moreover, these conditions may significantly alter experimental outcomes. Media glucose concentration should be monitored during any culture experiments and utilization of middle glucose media is recommended for all vascular cell types.

Abstract P171: Glucose Consumption Of Vascular Cell Types In Culture; Toward Optimization Of Experimental Conditions

Any experimental outcomes are potentially influenced by extracellular glucose availability and its cellular metabolism. However, there is a lack of attention paid to the supply and utilization of glucose in many cultured experiments. Surveillance of vascular related journals for the past 5 years demonstrated that less than 20% of published articles declared the medium glucose concentration. The present studies were designed to seek ideal medium glucose concentration(s) in various cell types with particular attention paid to changes in glucose consumption. By using distinct glucose concentrations in Dulbecco's Modified Eagle's medium (DMEM), we identified ideal glucose media for stimulation experiments. We have compared glucose consumption in three vascular cell types, endothelial cells (EC), vascular smooth muscle cells (VSMC) and adventitial fibroblasts (AF) with or without angiotensin II (AII) stimulation. In all cell types after a 48h incubation in relatively low glucose media (1 g/L), medium glucose concentration was reduced to almost 0 (EC 0.01±0.01 g/L, VSMC 0.13±0.05 g/L, AF 0.02±0.01 g/L). Whereas medium glucose concentration remained significantly higher (EC 2.77±0.05 g/L, VSMC 3.87±0.05 g/L, AF 3.32±0.01 g/L) when cells were incubated for 48h in high glucose (4.5 g/L) media. In middle glucose (2.75 g/L) media, medium glucose concentration remained in physiological ranges (EC 0.62±0.18 g/L, VSMC 1.98±0.07 g/L, AF 1.17±0.17 g/L). AII treatment enhanced glucose consumption in AF and low passage VSMC but not in EC. In AF, AII induction of target proteins varied depending on the glucose concentration used. In low glucose media induction of Grp78 or hexokinase II was highest, whereas induction of VCAM1 was lowest. Utilization of specific inhibitors further suggest essential roles of AT1 receptor and glycolysis in AII-induced fibroblast activation. Overall, the present study demonstrates a high risk of hypo- or hyperglycemic conditions when standard low or high glucose media is used with vascular cells. Moreover, these conditions may significantly alter experimental outcomes. Medium glucose concentration should be monitored during any culture experiments and utilization of middle glucose media is recommended for all vascular cell types.

Abstract P218: Ume ( Prunus Mume ) Attenuates Er Stress And Inflammation In Rat Vascular Smooth Muscle Cells

Ume ( Prunus mume ), is a traditional and familiar food in Asian countries, and is most often pickled or used to make wine and juice concentrate. Recently, Ume is attracting attention as a health food. We previously reported that Ume attenuates the activation of EGFR-ERK cascade and ROS production induced by angiotensin II (Ang II) in vascular smooth muscle cells (VSMC) of thoracic aorta. However, how Ume works on vascular inflammation and ER stress still remains unknown. AngII may enhance inflamm-aging via ER stress contributing to arterial stiffness and hypertension.We used primary culture of rat VSMC for experiment. We obtained 5 fractions (methanol, hexane, dichloromethane, ethyl acetate, and water) extracted from Ume juice. VSMC were pretreated with each fraction for 30 minutes followed by Ang II or tumor necrosis factor (TNF)-α stimulation. Stimulation period was 24 and 48 hours for Ang II, 6 hours for TNF-α. As the preliminary screening, we tested the cell response and solubility of each fraction (n=1~2). Pretreatment with 500μg/mL hexane fraction (PMF-H) showed the tendency to decrease VCAM1 expression under Ang II condition. PMF-H was completely soluble in the media at the concentration of 150 μg/mL. Based on this result, we focused on 150μg/mL PMF-H. DMSO was used as vehicle. In Western blot analysis, PMF-H attenuates ATF6 expression under both AII (p=0.0351, n=5) and TNF-α (p=0.0199, n=5) condition compared to vehicle. VCAM1 expression was significantly enhanced by Ang II stimulation (p=0.0471, n=5), and attenuated by PMF-H. PMF-H also reduced VCAM1 expression under TNF-α stimulation compared to vehicle (p=0.0377, n=5). GRP78 and Crystallin AB did not show any significant change. ATF6 and VCAM1 are key modulators of ER stress and vascular inflammation that may lead to cellular aging. Our results indicate PMF-H attenuates ATF6 and VCAM1 induced by Ang II or TNF-α stimulation. Thus, identification of the active ingredient in hexane fraction of Ume is desired as it may constitute a good candidate for a supplement or drug for anti-inflamm-aging therapy.

Abstract P170: Targeting Angiotensin Ii-induced Endoplasmic Reticulum Stress In Vsmcs To Reduce Pathological Vascular Amyloid Burden And Remodeling

Hypertension is a complex disorder and risk factor for cardiovascular disease, ultimately contributing to premature death. The societal burden of hypertension is enormous, therefore better understanding of molecular mechanisms underlying hypertension and associated pathological vascular remodeling is needed for mechanism-targeted therapy development. Endoplasmic reticulum (ER) stress occurs in cells under increased protein synthesis, Ca 2+ flux, or ROS generating environments- all of which are induced by Angiotensin II signaling in vascular cells. ER stress leads to the accumulation of misfolded proteins, and mediates cell death, fibrotic, and hypertrophic responses. The aim of this study was to target ER stress via chemical chaperone 3-hydroxy-2-naphthoic acid (3HNA) or genetic overexpression of chaperone glucose-regulated protein 78 (GRP78) to reduce protein aggregation and pathological response in VSMCs. Rat primary VSMCs were treated with 500 μM 3HNA or 30 MOI lacZ-GRP78 prior to stimulation with Ang II (100 nM). Protein synthesis assessed via puromycin incorporation revealed ER stress inhibition blocked Ang II associated protein synthesis in VSMCs, fold change relative to control of 1.7 (saline + Ang II) to 1.2 (3-HNA + Ang II) treated cells (P<0.05). GRP78 overexpression attenuated Ang II induction pre-amyloid oligomers (P<0.01) from 2.1 aggregates/cell to 0.9 aggregates/cell. Proteomic assessment of aggregates revealed Ang II induced crystallin AB (1.3 fold rel to control), HSP70 (1.716 fold rel to control) and annexin a2 (1.3 fold increase) enrichment in detergent insoluble fractions, which was attenuated by GRP78 overexpression (P=0.03, 0.03, and 0.024, respectively). In a 2 week Ang II infusion model, 3HNA was injected in C57/Bl6 mice. Ang II-induced medial thickness and cardiac vessel fibrosis was significantly reduced by 3-HNA (P<0.05). SM22α Cre GRP78 mice were generated and found protective against Ang II induced cardiac hypertrophy via HW/BW ratio (Cre- vs Cre+ Ang II P<0.05), and a trend in reduction of aortic medial thickness (P=0.098). Overall, GRP78 chaperone expression reduced protein aggregation and subsequent vascular remodeling induced by hypertensive stimulus and may elude novel therapeutic targets.

Vascular Stress Signaling in Hypertension

Cells respond to stress by activating a variety of defense signaling pathways, including cell survival and cell death pathways. Although cell survival signaling helps the cell to recover from acute insults, cell death or senescence pathways induced by chronic insults can lead to unresolved pathologies. Arterial hypertension results from chronic physiological maladaptation against various stressors represented by abnormal circulating or local neurohormonal factors, mechanical stress, intracellular accumulation of toxic molecules, and dysfunctional organelles. Hypertension and aging share common mechanisms that mediate or prolong chronic cell stress, such as endoplasmic reticulum stress and accumulation of protein aggregates, oxidative stress, metabolic mitochondrial stress, DNA damage, stress-induced senescence, and proinflammatory processes. This review discusses common adaptive signaling mechanisms against these stresses including unfolded protein responses, antioxidant response element signaling, autophagy, mitophagy, and mitochondrial fission/fusion, STING (signaling effector stimulator of interferon genes)-mediated responses, and activation of pattern recognition receptors. The main molecular mechanisms by which the vasculature copes with hypertensive and aging stressors are presented and recent advancements in stress-adaptive signaling mechanisms as well as potential therapeutic targets are discussed.

Abstract P116: Inhibition of Ang II-Induced Mitochondrial Fission and Endoplasmic Reticulum Stress Attenuates Protein Aggregate Accumulation, Inflammation, and Senescence in Vascular Smooth Muscle Cells

Aging is a non-modifiable risk factor for most cardiovascular diseases (CVDs) including hypertension and abdominal aortic aneurysms (AAA). As much as 14-year difference was noted in vascular aging assessed by arterial stiffness in healthy middle age human population, suggesting that premature vascular aging is a promising therapeutic target to combat against CVD. The molecular mechanisms involved in Ang II induction of premature vascular aging and how these contribute to CVD development are poorly understood. The objective of this study was to elucidate involvement of mitochondria and endoplasmic reticulum (ER) dynamics in Ang II-induced senescence in vascular smooth muscle cells (VSMCs), and how these contribute to CVDs. Ang II is known to promote mitochondrial fission and increases oxidative stress, and subsequent ER stress. Thus, chronic activation of Ang II signaling has been reported here to cause proteotoxicity due to accumulation of protein aggregates. Sodium 4-phenylbutyrate (PBA) increases ER folding capacity to restore proper protein folding and attenuate activation of UPR. Our in vitro data show Ang II enhances protein aggregate formation and PBA pretreatment alleviates their cellular accumulation in both size and number. Treatment of rat aortic VSMCs with 4-PBA or mitochondrial fission inhibitor mdivi1 mitigates Ang II induced VSMC senescence, detected by 4% (p=0.04) and 5% (p=0.02) reduction in senescence-associated β galactosidase (SA-β gal) positive cells, respectively. Ang II induced VSMC inflammation was monitored by THP-1 adhesion assay with a 1.87 fold increase in leukocyte adhesion (p=0.017), which was attenuated by PBA. In vivo , male C57/B6 mice infused with Ang II (4 weeks) with beta-aminopropionitrile (drinking water) (AAA model) +/- mdivi1 25 mg/kg IP 3x per week), which reduced AAA development, ER stress, leukocyte infiltration, and senescence. Taken together, these data represent a unique signaling pathway whereby Ang II-induced mitochondrial fission contributes to disturbed proteostasis, culminating in VSMC senescence and vascular inflamm-aging. The elucidation of Ang II contribution to irreversible vascular senescence sheds light on potential alternative therapeutic targets for high-risk CVD populations.

Cell confluency analysis on microcarriers by micro-flow imaging

The productivity of cell culture-derived vaccines grown in anchorage-dependent animal cells is limited by bioreactor surface area. One way to increase the available surface area is by growing cells as monolayers on small spheres called microcarriers, which are approximately 100-250 μm in diameter. In order for microcarrier-based cell culture to be a success, it is important to understand the kinetics of cell growth on the microcarriers. Micro-flow imaging (MFI) is a simple and powerful technique that captures images and analyzes samples as they are drawn through a precision flow cell. In addition to providing size distribution and defect frequency data to compare microcarrier lots, MFI was used to generate hundreds of images to determine cell coverage and confluency on microcarriers. Same-day manual classification of these images provided upstream cell culture teams with actionable data that informed in-process decision making (e.g. time of infection). Additionally, an automated cell coverage algorithm was developed to increase the speed and throughput of the analyses.