miR‐mediated regulation of coronary collateral growth in the metabolic syndrome

We have previously demonstrated that Akt was required for repetitive ischemia (RI)-induced coronary collateral growth (CCG) in healthy rats but was not activated by RI in the metabolic syndrome (JCR:LA-cp rats) where CCG was impaired. Here we hypothesized that failure of angiotensin type I receptor (AT1R) blockers to restore Akt activation is a key determinant of their inability to completely restore CCG in the metabolic syndrome. Therefore, we investigated whether adenovirus-mediated delivery of constitutively active Akt (MyrAkt-Adv) in conjunction with AT1R blockade (candesartan) was able to restore RI-induced CCG in JCR:LA-cp rats. Successful myocardial MyrAkt-Adv delivery was confirmed by a >80% transduction efficiency and an approximately fourfold increase in Akt expression and activation. CCG was assessed by myocardial blood flow measurements in the normal and collateral-dependent zones. MyrAkt-Adv alone significantly increased RI-induced CCG in JCR:LA-cp rats (∼30%), but it completely restored CCG in conjunction with administration of candesartan. In contrast, dominant negative Akt (DN-Akt-Adv) reversed the beneficial effect of candesartan on CCG in JCR:LA-cp rats. We conclude that optimal restoration of coronary collateral growth in JCR:LA-cp rats requires a combination of AT1R blockade with constitutive Akt activation. These findings may carry implications for metabolic syndrome patients in need of coronary revascularization.

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Abstract P129: 20-HETE Antagonist, 20-SOLA, Restores Coronary Collateral Growth in the Metabolic Syndrome

Hypertension ◽

10.1161/hyp.66.suppl_1.p129 ◽

2015 ◽

Vol 66 (suppl_1) ◽

Author(s):

Amanda A Soler ◽

Brenda Hutcheson ◽

Manuel A Devila-Molina ◽

Ian Hunter ◽

Victor G Garcia ◽

...

Keyword(s):

Metabolic Syndrome ◽

Arachidonic Acid Metabolite ◽

Collateral Flow ◽

Rt Pcr ◽

Coronary Collateral ◽

The Metabolic Syndrome ◽

Cardiovascular Tissues ◽

Hypertensive Animal ◽

Collateral Growth ◽

Coronary Collateral Growth

We have previously shown that transient and repetitive ischemia-induced (RI) coronary collateral growth (CCG) was severely impaired in a metabolic syndrome rat model (JCR rat). Levels of 20-hydroxyeicosatetraeonic acid (20-HETE), a cytochrome (CYP)-derived arachidonic acid metabolite are greatly elevated in hypertensive animal models and loosely associated with obesity in humans, but its levels in metabolic syndrome, especially in cardiovascular tissues, as well as its possible involvement in the regulation of collateral growth are unknown. In rats, CYP4A1 is the major enzyme responsible for the production of 20-HETE. In this study, we demonstrated that cardiac CYP4A1 expression (RT-PCR, Western blot and immunohistochemistry) and 20-HETE levels were markedly (10-fold) elevated in JCR vs. Sprague-Dawly (SD) rats in response to RI. Importantly, administration of an antagonist of 20-HETE, 20-SOLA, completely restored CCG in JCR rats (collateral flow was 86±1% of that in the normal zone (JCR+SOLA) vs. 21±2% (JCR) vs. 84±5% (SD), p<0.05). We conclude that 20-HETE is an important modulator of CCG in the metabolic syndrome where its myocardial tissue levels are highly elevated.

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MicroRNA-145 Restores Contractile Vascular Smooth Muscle Phenotype and Coronary Collateral Growth in the Metabolic Syndrome

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvbaha.112.301116 ◽

2013 ◽

Vol 33 (4) ◽

pp. 727-736 ◽

Cited By ~ 47

Author(s):

Rebecca Hutcheson ◽

Russell Terry ◽

Jennifer Chaplin ◽

Erika Smith ◽

Alla Musiyenko ◽

...

Keyword(s):

Metabolic Syndrome ◽

Smooth Muscle ◽

Vascular Smooth Muscle ◽

Coronary Collateral ◽

The Metabolic Syndrome ◽

Collateral Growth ◽

Coronary Collateral Growth

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miR-21-mediated decreased neutrophil apoptosis is a determinant of impaired coronary collateral growth in metabolic syndrome

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00654.2014 ◽

2015 ◽

Vol 308 (11) ◽

pp. H1323-H1335 ◽

Cited By ~ 9

Author(s):

Rebecca Hutcheson ◽

Russell Terry ◽

Brenda Hutcheson ◽

Rashmi Jadhav ◽

Jennifer Chaplin ◽

...

Keyword(s):

Oxidative Stress ◽

Metabolic Syndrome ◽

Cytochrome C ◽

Stress Generation ◽

Neutrophil Apoptosis ◽

Cytochrome C Release ◽

Coronary Collateral ◽

Sd Rats ◽

Collateral Growth ◽

Coronary Collateral Growth

Coronary collateral growth (CCG) is impaired in metabolic syndrome. microRNA-21 (miR-21) is a proproliferative and antiapoptotic miR, which we showed to be elevated in metabolic syndrome. Here we investigate whether impaired CCG in metabolic syndrome involved miR-21-mediated aberrant apoptosis. Normal Sprague-Dawley (SD) and metabolic syndrome [J. C. Russel (JCR)] rats underwent transient, repetitive coronary artery occlusion [repetitive ischemia (RI)]. Antiapoptotic Bcl-2, phospho-Bad, and Bcl-2/Bax dimers were increased on days 6 and 9 RI, and proapoptotic Bax and Bax/Bax dimers and cytochrome- c release concurrently decreased in JCR versus SD rats. Active caspases were decreased in JCR versus SD rats (∼50%). Neutrophils increased transiently on day 3 RI in the collateral-dependent zone of SD rats but remained elevated in JCR rats, paralleling miR-21 expression. miR-21 downregulation by anti-miR-21 induced neutrophil apoptosis and decreased Bcl-2 and Bcl-2/Bax dimers (∼75%) while increasing Bax/Bax dimers, cytochrome- c release, and caspase activation (∼70, 400, and 400%). Anti-miR-21 also improved CCG in JCR rats (∼60%). Preventing neutrophil infiltration with blocking antibodies resulted in equivalent CCG recovery, confirming a major role for deregulated neutrophil apoptosis in CCG impairment. Neutrophil and miR-21-dependent CCG inhibition was in significant part mediated by increased oxidative stress. We conclude that neutrophil apoptosis is integral to normal CCG and that inappropriate prolonged miR-21-mediated survival of neutrophils plays a major role in impaired CCG, in part via oxidative stress generation.

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Abstract P168: 20-HETE-mediated Neutrophil Adhesion Impairs Coronary Collateral Growth in Metabolic Syndrome

Hypertension ◽

10.1161/hyp.68.suppl_1.p168 ◽

2016 ◽

Vol 68 (suppl_1) ◽

Author(s):

Gregory Joseph ◽

Amanda Soler ◽

Rebecca Hutcheson ◽

Ian Hunter ◽

Brenda Hutcheson ◽

...

Keyword(s):

Metabolic Syndrome ◽

Neutrophil Adhesion ◽

No Production ◽

Neutrophil Accumulation ◽

Coronary Collateral ◽

Sd Rats ◽

Collateral Growth ◽

Coronary Collateral Growth ◽

And Function ◽

Blocking Antibodies

Transient, repetitive myocardial ischemia (RI)-induced coronary collateral growth (CCG) is impaired in metabolic syndrome patients and animal models. Endothelial cell (EC) dysfunction and chronic inflammation are hallmarks of metabolic syndrome. We showed that while in normal animals (SD), RI induces transient infiltration of monocytes, associated with successful CCG, in metabolic syndrome rats (JCR), RI induces sustained accumulation of neutrophils, which contributes to compromised CCG. 20-hydroxyeicosatetraeonic acid (20-HETE) is a pro-inflammatory metabolite of arachidonic acid. Its role in the regulation of CCG is unknown. We hypothesized that enhanced 20-HETE-mediated neutrophil adhesion to ECs and consequent EC dysfunction and apoptosis result in impaired CCG in metabolic syndrome. P-selectin and ICAM-1 expression was increased ~40% in JCR vs. SD rats. This increase was prevented by 20-HETE antagonists, 20-SOLA or 20-HEDGE. 20-HETE antagonists also prevented neutrophil accumulation observed in JCR rats. Coronary arteries from JCR rats exhibited reduced endothelium (Ach)-dependent vasodilation (20% JCR vs. 50% of max. SD). RI-induced eNOS activation and NO production were likewise decreased (~60% and~70%, respectively) in JCR vs. SD rats. EC apoptosis (TUNEL) was severely increased in response to RI in JCR rats (~75% vs. SD). Neutrophil adhesion-blocking antibodies partially attenuated EC apoptosis (~70%) and EC dysfunction (~75% eNOS activation and NO production, 75% Ach-dependent vasodilation). 20-HETE antagonists fully reversed impaired endothelium-dependent vasodilation, eNOS activation, NO production and prevented EC apoptosis. Finally, impaired CCG in JCR rats (collateral-dependent blood flow, microspheres) was completely restored by 20-HETE antagonists (CZ/NZ flow was 0.76±0.07 in JCR+20-SOLA, 0.84±0.05 in JCR+20-HEDGE vs. 0.11±0.02 in JCR vs. 0.84±0.03 ml/min/g in SD rats) and partially restored by neutrophil-blocking antibodies (0.49±0.05 ml/min/g). Taken together, these results indicate that 20-HETE-dependent neutrophil adhesion and accumulation compromises EC survival and function leading to impaired CCG. 20-HETE antagonists could provide therapy for restoration of CCG in metabolic syndrome.

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Redox-sensitive Akt and Src regulate coronary collateral growth in metabolic syndrome

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.00920.2008 ◽

2009 ◽

Vol 296 (6) ◽

pp. H1811-H1821 ◽

Cited By ~ 19

Author(s):

Ryan Reed ◽

Barry Potter ◽

Erika Smith ◽

Rashmi Jadhav ◽

Patricia Villalta ◽

...

Keyword(s):

Oxidative Stress ◽

Metabolic Syndrome ◽

Akt Activation ◽

Wky Rats ◽

Coronary Collateral ◽

Upstream Regulator ◽

Myocardial Oxidative Stress ◽

Collateral Growth ◽

Src Activation ◽

Coronary Collateral Growth

We have recently shown that the inability of repetitive ischemia (RI) to activate p38 MAPK (p38) and Akt in metabolic syndrome [JCR:LA-cp (JCR)] rats was associated with impaired coronary collateral growth (CCG). Furthermore, Akt and p38 activation correlated with optimal O2−· levels and were altered in JCR rats, and redox-sensitive p38 activation was required for CCG. Here, we determined whether the activation of Src, a possible upstream regulator, was altered in JCR rats and whether redox-dependent Src and Akt activation were required for CCG. CCG was assessed by myocardial blood flow (microspheres) and kinase activation was assessed by Western blot analysis in the normal zone and collateral-dependent zone (CZ). RI induced Src activation (∼3-fold) in healthy [Wistar-Kyoto (WKY)] animals but not in JCR animals. Akt inhibition decreased (∼50%), and Src inhibition blocked RI-induced CCG in WKY rats. Src inhibition decreased p38 and Akt activation. Myocardial oxidative stress (O2−· and oxidized/reduced thiols) was measured quantitatively (X-band electron paramagnetic resonance). An antioxidant, apocynin, reduced RI-induced oxidative stress in JCR rats to levels induced by RI in WKY rats versus the reduction in WKY rats to very low levels. This resulted in a significant restoration of p38 (∼80%), Akt (∼65%), and Src (∼90%) activation in JCR rats but decreased the activation in WKY rats (p38: ∼45%, Akt: ∼65%, and Src: ∼100%), correlating with reduced CZ flow in WKY rats (∼70%), but significantly restored CZ flow in JCR rats (∼75%). We conclude that 1) Akt and Src are required for CCG, 2) Src is a redox-sensitive upstream regulator of RI-induced p38 and Akt activation, and 3) optimal oxidative stress levels are required for RI-induced p38, Akt, and Src activation and CCG.

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