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Islam MT, Cai J, Allen S, Moreno DG, Bloom SI, Bramwell RC, Mitton J, Horn AG, Zhu W, Donato AJ, Holland WL, Lesniewski LA. Endothelial-Specific Reduction in Arf6 Impairs Insulin-Stimulated Vasodilation and Skeletal Muscle Blood Flow Resulting in Systemic Insulin Resistance in Mice. Arterioscler Thromb Vasc Biol 2024; 44:1101-1113. [PMID: 38545783 DOI: 10.1161/atvbaha.123.319375] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2023] [Accepted: 02/27/2024] [Indexed: 04/09/2024]
Abstract
BACKGROUND Much of what we know about insulin resistance is based on studies from metabolically active tissues such as the liver, adipose tissue, and skeletal muscle. Emerging evidence suggests that the vascular endothelium plays a crucial role in systemic insulin resistance; however, the underlying mechanisms remain incompletely understood. Arf6 (ADP ribosylation factor 6) is a small GTPase that plays a critical role in endothelial cell function. Here, we tested the hypothesis that the deletion of endothelial Arf6 will result in systemic insulin resistance. METHODS We used mouse models of constitutive endothelial cell-specific Arf6 deletion (Arf6f/- Tie2Cre+) and tamoxifen-inducible Arf6 knockout (Arf6f/f Cdh5CreER+). Endothelium-dependent vasodilation was assessed using pressure myography. Metabolic function was assessed using a battery of metabolic assessments including glucose and insulin tolerance tests and hyperinsulinemic-euglycemic clamps. We used a fluorescence microsphere-based technique to measure tissue blood flow. Skeletal muscle capillary density was assessed using intravital microscopy. RESULTS Endothelial Arf6 deletion impaired insulin-stimulated vasodilation in white adipose tissue and skeletal muscle feed arteries. The impairment in vasodilation was primarily due to attenuated insulin-stimulated nitric oxide bioavailability but independent of altered acetylcholine-mediated or sodium nitroprusside-mediated vasodilation. Endothelial cell-specific deletion of Arf6 also resulted in systematic insulin resistance in normal chow-fed mice and glucose intolerance in high-fat diet-fed obese mice. The underlying mechanisms of glucose intolerance were reductions in insulin-stimulated blood flow and glucose uptake in the skeletal muscle and were independent of changes in capillary density or vascular permeability. CONCLUSIONS Results from this study support the conclusion that endothelial Arf6 signaling is essential for maintaining insulin sensitivity. Reduced expression of endothelial Arf6 impairs insulin-mediated vasodilation and results in systemic insulin resistance. These results have therapeutic implications for diseases that are associated with endothelial cell dysfunction and insulin resistance such as diabetes.
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Affiliation(s)
- Md Torikul Islam
- Department of Nutrition and Integrative Physiology (M.T.I., S.I.B., A.J.D., W.L.H., L.A.L.), The University of Utah, Salt Lake City
| | - Jinjin Cai
- Division of Geriatrics, Department of Internal Medicine (J.C., S.A., D.G.M., R.C.B., J.M., A.J.D., L.A.L.), The University of Utah, Salt Lake City
| | - Shanena Allen
- Division of Geriatrics, Department of Internal Medicine (J.C., S.A., D.G.M., R.C.B., J.M., A.J.D., L.A.L.), The University of Utah, Salt Lake City
| | - Denisse G Moreno
- Division of Geriatrics, Department of Internal Medicine (J.C., S.A., D.G.M., R.C.B., J.M., A.J.D., L.A.L.), The University of Utah, Salt Lake City
| | - Samuel I Bloom
- Department of Nutrition and Integrative Physiology (M.T.I., S.I.B., A.J.D., W.L.H., L.A.L.), The University of Utah, Salt Lake City
| | - R Colton Bramwell
- Division of Geriatrics, Department of Internal Medicine (J.C., S.A., D.G.M., R.C.B., J.M., A.J.D., L.A.L.), The University of Utah, Salt Lake City
| | - Jonathan Mitton
- Division of Geriatrics, Department of Internal Medicine (J.C., S.A., D.G.M., R.C.B., J.M., A.J.D., L.A.L.), The University of Utah, Salt Lake City
| | - Andrew G Horn
- Department of Kinesiology, Kansas State University, Manhattan (A.G.H.)
| | - Weiquan Zhu
- Division of Cardiovascular Medicine, Department of Internal Medicine (W.Z.), The University of Utah, Salt Lake City
- Department of Pathology (W.Z.), The University of Utah, Salt Lake City
- Program of Molecular Medicine (W.Z.), The University of Utah, Salt Lake City
| | - Anthony J Donato
- Department of Nutrition and Integrative Physiology (M.T.I., S.I.B., A.J.D., W.L.H., L.A.L.), The University of Utah, Salt Lake City
- Division of Geriatrics, Department of Internal Medicine (J.C., S.A., D.G.M., R.C.B., J.M., A.J.D., L.A.L.), The University of Utah, Salt Lake City
- Department of Biochemistry (A.J.D.), The University of Utah, Salt Lake City
- Nora Eccles Harrison Cardiovascular Research and Training Institute (A.J.D., L.A.L.), The University of Utah, Salt Lake City
- Veteran's Affairs Medical Center-Salt Lake City, Geriatric Research and Clinical Center, UT (A.J.D., L.A.L.)
| | - William L Holland
- Department of Nutrition and Integrative Physiology (M.T.I., S.I.B., A.J.D., W.L.H., L.A.L.), The University of Utah, Salt Lake City
| | - Lisa A Lesniewski
- Department of Nutrition and Integrative Physiology (M.T.I., S.I.B., A.J.D., W.L.H., L.A.L.), The University of Utah, Salt Lake City
- Division of Geriatrics, Department of Internal Medicine (J.C., S.A., D.G.M., R.C.B., J.M., A.J.D., L.A.L.), The University of Utah, Salt Lake City
- Nora Eccles Harrison Cardiovascular Research and Training Institute (A.J.D., L.A.L.), The University of Utah, Salt Lake City
- Veteran's Affairs Medical Center-Salt Lake City, Geriatric Research and Clinical Center, UT (A.J.D., L.A.L.)
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Islam MT, Hall SA, Dutson T, Bloom SI, Bramwell RC, Kim J, Tucker JR, Machin DR, Donato AJ, Lesniewski LA. Endothelial cell-specific reduction in mTOR ameliorates age-related arterial and metabolic dysfunction. Aging Cell 2024; 23:e14040. [PMID: 38017701 PMCID: PMC10861194 DOI: 10.1111/acel.14040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 10/04/2023] [Accepted: 10/23/2023] [Indexed: 11/30/2023] Open
Abstract
Systemic inhibition of the mammalian target of rapamycin (mTOR) delays aging and many age-related conditions including arterial and metabolic dysfunction. However, the mechanisms and tissues involved in these beneficial effects remain largely unknown. Here, we demonstrate that activation of S6K, a downstream target of mTOR, is increased in arteries with advancing age, and that this occurs preferentially in the endothelium compared with the vascular smooth muscle. Induced endothelial cell-specific deletion of mTOR reduced protein expression by 60-70%. Although this did not significantly alter arterial and metabolic function in young mice, endothelial mTOR reduction reversed arterial stiffening and improved endothelium-dependent dilation (EDD) in old mice, indicating an improvement in age-related arterial dysfunction. Improvement in arterial function in old mice was concomitant with reductions in arterial cellular senescence, inflammation, and oxidative stress. The reduction in endothelial mTOR also improved glucose tolerance in old mice, and this was associated with attenuated hepatic gluconeogenesis and improved lipid tolerance, but was independent of alterations in peripheral insulin sensitivity, pancreatic beta cell function, or fasted plasma lipids in old mice. Lastly, we found that endothelial mTOR reduction suppressed gene expression of senescence and inflammatory markers in endothelial-rich (i.e., lung) and metabolically active organs (i.e., liver and adipose tissue), which may have contributed to the improvement in metabolic function in old mice. This is the first evidence demonstrating that reducing endothelial mTOR in old age improves arterial and metabolic function. These findings have implications for future drug development.
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Affiliation(s)
- Md Torikul Islam
- Department of Nutrition and Integrative PhysiologyThe University of UtahSalt Lake CityUtahUSA
| | - Shelby A. Hall
- Department of Nutrition and Integrative PhysiologyThe University of UtahSalt Lake CityUtahUSA
| | - Tavia Dutson
- Division of Geriatrics, Department of Internal MedicineThe University of Utah School of MedicineSalt Lake CityUtahUSA
| | - Samuel I. Bloom
- Department of Nutrition and Integrative PhysiologyThe University of UtahSalt Lake CityUtahUSA
| | - R. Colton Bramwell
- Division of Geriatrics, Department of Internal MedicineThe University of Utah School of MedicineSalt Lake CityUtahUSA
| | - John Kim
- Nora Eccles Harrison Cardiovascular Research and Training InstituteThe University of UtahSalt Lake CityUtahUSA
| | - Jordan R. Tucker
- Division of Geriatrics, Department of Internal MedicineThe University of Utah School of MedicineSalt Lake CityUtahUSA
| | - Daniel R. Machin
- Division of Geriatrics, Department of Internal MedicineThe University of Utah School of MedicineSalt Lake CityUtahUSA
| | - Anthony J. Donato
- Department of Nutrition and Integrative PhysiologyThe University of UtahSalt Lake CityUtahUSA
- Division of Geriatrics, Department of Internal MedicineThe University of Utah School of MedicineSalt Lake CityUtahUSA
- Nora Eccles Harrison Cardiovascular Research and Training InstituteThe University of UtahSalt Lake CityUtahUSA
- Geriatric Research Education and Clinical CenterVeteran's Affairs Medical CenterSalt Lake CityUtahUSA
- Department of BiochemistryThe University of UtahSalt Lake CityUtahUSA
| | - Lisa A. Lesniewski
- Department of Nutrition and Integrative PhysiologyThe University of UtahSalt Lake CityUtahUSA
- Division of Geriatrics, Department of Internal MedicineThe University of Utah School of MedicineSalt Lake CityUtahUSA
- Nora Eccles Harrison Cardiovascular Research and Training InstituteThe University of UtahSalt Lake CityUtahUSA
- Geriatric Research Education and Clinical CenterVeteran's Affairs Medical CenterSalt Lake CityUtahUSA
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Bloom SI, Tucker JR, Machin DR, Abdeahad H, Adeyemo AO, Thomas TG, Bramwell RC, Lesniewski LA, Donato AJ. Reduction of double-strand DNA break repair exacerbates vascular aging. Aging (Albany NY) 2023; 15:9913-9947. [PMID: 37787989 PMCID: PMC10599741 DOI: 10.18632/aging.205066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Accepted: 08/28/2023] [Indexed: 10/04/2023]
Abstract
Advanced age is the greatest risk factor for cardiovascular disease (CVD), the leading cause of death. Arterial function is impaired in advanced age which contributes to the development of CVD. One underexplored hypothesis is that DNA damage within arteries leads to this dysfunction, yet evidence demonstrating the incidence and physiological consequences of DNA damage in arteries, and in particular, in the microvasculature, in advanced age is limited. In the present study, we began by assessing the abundance of DNA damage in human and mouse lung microvascular endothelial cells and found that aging increases the percentage of cells with DNA damage. To explore the physiological consequences of increases in arterial DNA damage, we evaluated measures of endothelial function, microvascular and glycocalyx properties, and arterial stiffness in mice that were lacking or heterozygous for the double-strand DNA break repair protein ATM kinase. Surprisingly, in young mice, vascular function remained unchanged which led us to rationalize that perhaps aging is required to accumulate DNA damage. Indeed, in comparison to wild type littermate controls, mice heterozygous for ATM that were aged to ~18 mo (Old ATM +/-) displayed an accelerated vascular aging phenotype characterized by increases in arterial DNA damage, senescence signaling, and impairments in endothelium-dependent dilation due to elevated oxidative stress. Furthermore, old ATM +/- mice had reduced microvascular density and glycocalyx thickness as well as increased arterial stiffness. Collectively, these data demonstrate that DNA damage that accumulates in arteries in advanced age contributes to arterial dysfunction that is known to drive CVD.
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Affiliation(s)
- Samuel I. Bloom
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT 84148, USA
| | - Jordan R. Tucker
- Department of Internal Medicine, Division of Geriatrics, University of Utah School of Medicine, Salt Lake City, UT 84148, USA
| | - Daniel R. Machin
- Department of Nutrition and Integrative Physiology, Florida State University, Tallahassee, FL 32304, USA
| | - Hossein Abdeahad
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT 84148, USA
| | - AdeLola O. Adeyemo
- Department of Internal Medicine, Division of Geriatrics, University of Utah School of Medicine, Salt Lake City, UT 84148, USA
| | - Tyler G. Thomas
- Department of Internal Medicine, Division of Geriatrics, University of Utah School of Medicine, Salt Lake City, UT 84148, USA
| | - R. Colton Bramwell
- Department of Internal Medicine, Division of Geriatrics, University of Utah School of Medicine, Salt Lake City, UT 84148, USA
| | - Lisa A. Lesniewski
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT 84148, USA
- Department of Internal Medicine, Division of Geriatrics, University of Utah School of Medicine, Salt Lake City, UT 84148, USA
- Geriatric Research, Education and Clinical Center, Veteran’s Affairs Medical Center-Salt Lake City, Salt Lake City, UT 84148, USA
- Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84148, USA
| | - Anthony J. Donato
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT 84148, USA
- Department of Internal Medicine, Division of Geriatrics, University of Utah School of Medicine, Salt Lake City, UT 84148, USA
- Geriatric Research, Education and Clinical Center, Veteran’s Affairs Medical Center-Salt Lake City, Salt Lake City, UT 84148, USA
- Nora Eccles Harrison Cardiovascular Research and Training Institute, The University of Utah, Salt Lake City, UT 84148, USA
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84148, USA
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Machin DR, Trott DW, Gogulamudi VR, Islam MT, Bloom SI, Vink H, Lesniewski LA, Donato AJ. Glycocalyx-targeted therapy ameliorates age-related arterial dysfunction. GeroScience 2023; 45:2351-2365. [PMID: 36787090 PMCID: PMC10651573 DOI: 10.1007/s11357-023-00745-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Accepted: 01/26/2023] [Indexed: 02/15/2023] Open
Abstract
Advanced age is accompanied by arterial dysfunction, as well as a diminished glycocalyx, which may be linked to reduced high molecular weight-hyaluronan (HMW-HA) synthesis. However, the impact of glycocalyx deterioration in age-related arterial dysfunction is unknown. We sought to determine if manipulations in glycocalyx properties would alter arterial function. Tamoxifen-induced hyaluronan synthase 2 (Has2) reduction was used to decrease glycocalyx properties. Three weeks post-tamoxifen treatment, glycocalyx thickness was lower in Has2 knockout compared to wild-type mice (P<0.05). Has2 reduction induced arterial dysfunction, demonstrated by impaired endothelium-dependent dilation (EDD) and elevated aortic stiffness (P<0.05). To augment glycocalyx properties, old mice received 10 weeks of a glycocalyx-targeted therapy via Endocalyx™ (old+ECX), which contains HMW-HA and other glycocalyx components. Compared to old control mice, glycocalyx properties and EDD were augmented, and aortic stiffness decreased in old+ECX mice (P<0.05). Old+ECX mice had a more youthful aortic phenotype, demonstrated by lower collagen content and higher elastin content than old control mice (P<0.05). Functional outcomes were repeated in old mice that underwent a diet supplemented solely with HMW-HA (old+HA). Compared to old controls, glycocalyx properties and EDD were augmented, and aortic stiffness was lower in old+HA mice (P<0.05). We did not observe any differences between old+HA and old+ECX mice (P>0.05). Has2 reduction phenocopies age-related arterial dysfunction, while 10 weeks of glycocalyx-targeted therapy that restores the glycocalyx also ameliorates age-related arterial dysfunction. These findings suggest that the glycocalyx may be a viable therapeutic target to ameliorate age-related arterial dysfunction.
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Affiliation(s)
- Daniel R Machin
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA.
- Department of Nutrition and Integrative Physiology, Florida State University, Tallahassee, FL, 32306, USA.
| | - Daniel W Trott
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
| | | | - Md Torikul Islam
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Samuel I Bloom
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Hans Vink
- Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht, The Netherlands
- MicroVascular Health Solutions LLC, Alpine, UT, USA
| | - Lisa A Lesniewski
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
- VA Salt Lake City, GRECC, Salt Lake City, UT, USA
| | - Anthony J Donato
- Department of Internal Medicine, University of Utah, Salt Lake City, UT, USA
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
- VA Salt Lake City, GRECC, Salt Lake City, UT, USA
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA
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Bloom SI, Liu Y, Tucker JR, Islam MT, Machin DR, Abdeahad H, Thomas TG, Bramwell RC, Lesniewski LA, Donato AJ. Endothelial cell telomere dysfunction induces senescence and results in vascular and metabolic impairments. Aging Cell 2023; 22:e13875. [PMID: 37259606 PMCID: PMC10410008 DOI: 10.1111/acel.13875] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Revised: 04/03/2023] [Accepted: 05/04/2023] [Indexed: 06/02/2023] Open
Abstract
In advanced age, increases in oxidative stress and inflammation impair endothelial function, which contributes to the development of cardiovascular disease (CVD). One plausible source of this oxidative stress and inflammation is an increase in the abundance of senescent endothelial cells. Cellular senescence is a cell cycle arrest that occurs in response to various damaging stimuli. In the present study, we tested the hypothesis that advanced age results in endothelial cell telomere dysfunction that induces senescence. In both human and mouse endothelial cells, advanced age resulted in an increased abundance of dysfunctional telomeres, characterized by activation of DNA damage signaling at telomeric DNA. To test whether this results in senescence, we selectively reduced the telomere shelterin protein telomere repeat binding factor 2 (Trf2) from endothelial cells of young mice. Trf2 reduction increased endothelial cell telomere dysfunction and resulted in cellular senescence. Furthermore, induction of endothelial cell telomere dysfunction increased inflammatory signaling and oxidative stress, resulting in impairments in endothelial function. Finally, we demonstrate that endothelial cell telomere dysfunction-induced senescence impairs glucose tolerance. This likely occurs through increases in inflammatory signaling in the liver and adipose tissue, as well as reductions in microvascular density and vasodilation to metabolic stimuli. Cumulatively, the findings of the present study identify age-related telomere dysfunction as a mechanism that leads to endothelial cell senescence. Furthermore, these data provide compelling evidence that senescent endothelial cells contribute to age-related increases in oxidative stress and inflammation that impair arterial and metabolic function.
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Affiliation(s)
- Samuel I. Bloom
- Department of Nutrition and Integrative PhysiologyThe University of UtahSalt Lake CityUtahUSA
| | - Yu Liu
- Department of GeriatricsTongji HospitalWuhanChina
- Division of Geriatrics, Department of Internal MedicineUniversity of Utah School of MedicineSalt Lake CityUtahUSA
| | - Jordan R. Tucker
- Division of Geriatrics, Department of Internal MedicineUniversity of Utah School of MedicineSalt Lake CityUtahUSA
| | - Md Torikul Islam
- Department of Nutrition and Integrative PhysiologyThe University of UtahSalt Lake CityUtahUSA
| | - Daniel R. Machin
- Division of Geriatrics, Department of Internal MedicineUniversity of Utah School of MedicineSalt Lake CityUtahUSA
- Department of Nutrition and Integrative PhysiologyFlorida State UniversityTallahasseeFloridaUSA
| | - Hossein Abdeahad
- Department of Nutrition and Integrative PhysiologyThe University of UtahSalt Lake CityUtahUSA
| | - Tyler G. Thomas
- Division of Geriatrics, Department of Internal MedicineUniversity of Utah School of MedicineSalt Lake CityUtahUSA
| | - R. Colton Bramwell
- Division of Geriatrics, Department of Internal MedicineUniversity of Utah School of MedicineSalt Lake CityUtahUSA
| | - Lisa A. Lesniewski
- Department of Nutrition and Integrative PhysiologyThe University of UtahSalt Lake CityUtahUSA
- Division of Geriatrics, Department of Internal MedicineUniversity of Utah School of MedicineSalt Lake CityUtahUSA
- Geriatric Research, Education and Clinical CenterVeteran's Affairs Medical Center‐Salt Lake CitySalt Lake CityUtahUSA
- Nora Eccles Harrison Cardiovascular Research and Training InstituteThe University of UtahSalt Lake CityUtahUSA
| | - Anthony J. Donato
- Department of Nutrition and Integrative PhysiologyThe University of UtahSalt Lake CityUtahUSA
- Division of Geriatrics, Department of Internal MedicineUniversity of Utah School of MedicineSalt Lake CityUtahUSA
- Geriatric Research, Education and Clinical CenterVeteran's Affairs Medical Center‐Salt Lake CitySalt Lake CityUtahUSA
- Nora Eccles Harrison Cardiovascular Research and Training InstituteThe University of UtahSalt Lake CityUtahUSA
- Department of BiochemistryThe University of UtahSalt Lake CityUtahUSA
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Islam MT, Cai J, Allen S, Moreno DG, Bloom SI, Bramwell RC, Mitton J, Horn AG, Zhu W, Donato AJ, Holland WL, Lesniewski LA. Endothelial specific reduction in Arf6 impairs insulin-stimulated vasodilation and skeletal muscle blood flow resulting in systemic insulin resistance. bioRxiv 2023:2023.05.02.539173. [PMID: 37205339 PMCID: PMC10187242 DOI: 10.1101/2023.05.02.539173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Background Much of what we know about insulin resistance is based on studies from metabolically active tissues such as liver, adipose tissue, and skeletal muscle. Emerging evidence suggests that the vascular endothelium plays a crucial role in systemic insulin resistance, however, the underlying mechanisms remain incompletely understood. ADP ribosylation factor 6 (Arf6) is a small GTPase that plays a critical role in endothelial cell (EC) function. Here, we tested the hypothesis that the deletion of endothelial Arf6 will result in systemic insulin resistance. Methods We used mouse models of constitutive EC-specific Arf6 deletion (Arf6 f/- Tie2Cre) and tamoxifen inducible Arf6 knockout (Arf6 f/f Cdh5Cre). Endothelium-dependent vasodilation was assessed using pressure myography. Metabolic function was assessed using a battery of metabolic assessments including glucose- and insulin-tolerance tests and hyperinsulinemic-euglycemic clamps. A fluorescence microsphere-based technique was used to measure tissue blood flow. Intravital microscopy was used to assess skeletal muscle capillary density. Results Endothelial Arf6 deletion impaired insulin-stimulated vasodilation in white adipose tissue (WAT) and skeletal muscle feed arteries. The impairment in vasodilation was primarily due to attenuated insulin-stimulated nitric oxide (NO) bioavailability but independent of altered acetylcholine- or sodium nitroprusside-mediated vasodilation. In vitro Arf6 inhibition resulted in suppressed insulin stimulated phosphorylation of Akt and endothelial NO synthase. Endothelial cell-specific deletion of Arf6 also resulted in systematic insulin resistance in normal chow fed mice and glucose intolerance in high fat diet fed obese mice. The underlying mechanisms of glucose intolerance were reductions in insulin-stimulated blood flow and glucose uptake in the skeletal muscle and were independent of changes in capillary density or vascular permeability. Conclusion Results from this study support the conclusion that endothelial Arf6 signaling is essential for maintaining insulin sensitivity. Reduced expression of endothelial Arf6 impairs insulin-mediated vasodilation and results in systemic insulin resistance. These results have therapeutic implications for diseases that are associated with endothelial cell dysfunction and insulin resistance such as diabetes.
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Abstract
Endothelial cells are located at the crucial interface between circulating blood and semi-solid tissues and have many important roles in maintaining systemic physiological function. The vascular endothelium is particularly susceptible to pathogenic stimuli that activate tumour suppressor pathways leading to cellular senescence. We now understand that senescent endothelial cells are highly active, secretory and pro-inflammatory, and have an aberrant morphological phenotype. Moreover, endothelial senescence has been identified as an important contributor to various cardiovascular and metabolic diseases. In this Review, we discuss the consequences of endothelial cell exposure to damaging stimuli (haemodynamic forces and circulating and endothelial-derived factors) and the cellular and molecular mechanisms that induce endothelial cell senescence. We also discuss how endothelial cell senescence causes arterial dysfunction and contributes to clinical cardiovascular diseases and metabolic disorders. Finally, we summarize the latest evidence on the effect of eliminating senescent endothelial cells (senolysis) and identify important remaining questions to be addressed in future studies.
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Affiliation(s)
- Samuel I Bloom
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Md Torikul Islam
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Lisa A Lesniewski
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA
- Veterans Affairs Medical Center-Salt Lake City, Geriatric Research Education and Clinical Center, Salt Lake City, UT, USA
| | - Anthony J Donato
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA.
- Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, UT, USA.
- Veterans Affairs Medical Center-Salt Lake City, Geriatric Research Education and Clinical Center, Salt Lake City, UT, USA.
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA.
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Bloom SI, Tucker JR, Lim J, Thomas TG, Stoddard GJ, Lesniewski LA, Donato AJ. Aging results in DNA damage and telomere dysfunction that is greater in endothelial versus vascular smooth muscle cells and is exacerbated in atheroprone regions. GeroScience 2022; 44:2741-2755. [PMID: 36350415 PMCID: PMC9768045 DOI: 10.1007/s11357-022-00681-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 10/26/2022] [Indexed: 11/11/2022] Open
Abstract
Aging increases the risk of atherosclerotic cardiovascular disease which is associated with arterial senescence; however, the mechanisms responsible for the development of cellular senescence in endothelial cells (ECs) and vascular smooth muscle cells (VSMCs) remain elusive. Here, we study the effect of aging on arterial DNA damage and telomere dysfunction. Aging resulted in greater DNA damage in ECs than VSMCs. Further, telomere dysfunction-associated DNA damage foci (TAF: DNA damage signaling at telomeres) were elevated with aging in ECs but not VMSCs. Telomere length was modestly reduced in ECs with aging and not sufficient to induce telomere dysfunction. DNA damage and telomere dysfunction were greatest in atheroprone regions (aortic minor arch) versus non-atheroprone regions (thoracic aorta). Collectively, these data demonstrate that aging results in DNA damage and telomere dysfunction that is greater in ECs than VSMCs and elevated in atheroprone aortic regions.
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Affiliation(s)
- Samuel I Bloom
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Jordan R Tucker
- Department of Internal Medicine, Division of Geriatrics, University of Utah, VA Medical Center-SLC, GRECC Building 2, Rm 2D15A, 500 Foothill Dr., Salt Lake City, UT, USA
| | - Jisok Lim
- Department of Internal Medicine, Division of Geriatrics, University of Utah, VA Medical Center-SLC, GRECC Building 2, Rm 2D15A, 500 Foothill Dr., Salt Lake City, UT, USA
| | - Tyler G Thomas
- Department of Internal Medicine, Division of Geriatrics, University of Utah, VA Medical Center-SLC, GRECC Building 2, Rm 2D15A, 500 Foothill Dr., Salt Lake City, UT, USA
| | - Gregory J Stoddard
- Department of Internal Medicine, Division of Geriatrics, University of Utah, VA Medical Center-SLC, GRECC Building 2, Rm 2D15A, 500 Foothill Dr., Salt Lake City, UT, USA
| | - Lisa A Lesniewski
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
- Department of Internal Medicine, Division of Geriatrics, University of Utah, VA Medical Center-SLC, GRECC Building 2, Rm 2D15A, 500 Foothill Dr., Salt Lake City, UT, USA
- Geriatric Research and Clinical Center, Veteran's Affairs Medical Center-Salt Lake City, Salt Lake City, UT, USA
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, USA
| | - Anthony J Donato
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA.
- Department of Internal Medicine, Division of Geriatrics, University of Utah, VA Medical Center-SLC, GRECC Building 2, Rm 2D15A, 500 Foothill Dr., Salt Lake City, UT, USA.
- Geriatric Research and Clinical Center, Veteran's Affairs Medical Center-Salt Lake City, Salt Lake City, UT, USA.
- Nora Eccles Harrison Cardiovascular Research and Training Institute, University of Utah, Salt Lake City, UT, USA.
- Department of Biochemistry, University of Utah, Salt Lake City, UT, USA.
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Bloom SI, Tucker JR, Liu Y, Abdeahad H, Machin DR, Thomas TG, Bramwell RC, Islam MT, Lesniewski LA, Donato AJ. Aging results in endothelial cell telomere uncapping that induces senescence and physiological dysfunction. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r4606] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Samuel I. Bloom
- Nutrition and Integrative PhysiologyUniversity of UtahSalt Lake CityUT
| | | | - Yu Liu
- Department of GeriatricsTongji HospitalWuhan
| | - Hossein Abdeahad
- Nutrition and Integrative PhysiologyUniversity of UtahSalt Lake CityUT
| | - Daniel R. Machin
- Department oof Nutrition, Food, and Exercise SciencesFlorida State UniversityTallahasseeFL
| | | | | | - Md Torikul Islam
- Nutrition and Integrative PhysiologyUniversity of UtahSalt Lake CityUT
| | - Lisa A. Lesniewski
- Geriatric Research, Education and Clinical CenterVeterans Affairs Medical Center Salt Lake CitySalt Lake CityUT
- Nutrition and Integrative PhysiologyVeterans Affairs Medical Center Salt Lake CitySalt Lake CityUT
- Internal MedicineVeterans Affairs Medical Center Salt Lake CitySalt Lake CityUT
| | - Anthony J. Donato
- Nutrition and Integrative PhysiologyUniversity of UtahSalt Lake CityUT
- Internal MedicineUniversity of UtahSalt Lake CityUT
- BiochemistryUniversity of UtahSalt Lake CityUT
- Geriatric Research, Education and Clinical CenterUniversity of UtahSalt Lake CityUT
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10
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Islam MT, Hall SA, Bloom SI, Bramwell RC, Dutson T, Tucker JR, Kim J, Machin DR, Donato AJ, Lesniewski LA. Ablation of Endothelial mTOR is Benign in Young Mice and Reverses Age‐Related Arterial and Metabolic Impairments in Old Mice. FASEB J 2022. [DOI: 10.1096/fasebj.2022.36.s1.r6002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Md Torikul Islam
- Nutrition and Integrative PhysiologyUniversity of UtahSalt Lake CityUT
| | - Shelby A. Hall
- Nutrition and Integrative PhysiologyUniversity of UtahSalt Lake CityUT
| | - Samuel I. Bloom
- Nutrition and Integrative PhysiologyUniversity of UtahSalt Lake CityUT
| | | | - Tavia Dutson
- Internal MedicineUniversity of UtahSalt Lake CityUT
| | | | - John Kim
- Internal MedicineUniversity of UtahSalt Lake CityUT
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11
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Trott DW, Machin DR, Phuong TTT, Adeyemo AO, Bloom SI, Bramwell RC, Sorensen ES, Lesniewski LA, Donato AJ. T cells mediate cell non-autonomous arterial ageing in mice. J Physiol 2021; 599:3973-3991. [PMID: 34164826 DOI: 10.1113/jp281698] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2021] [Accepted: 06/21/2021] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Increased large artery stiffness and impaired endothelium-dependent dilatation occur with advanced age. We sought to determine whether T cells mechanistically contribute to age-related arterial dysfunction. We found that old mice exhibited greater proinflammatory T cell accumulation around both the aorta and mesenteric arteries. Pharmacologic depletion or genetic deletion of T cells in old mice resulted in ameliorated large artery stiffness and greater endothelium-dependent dilatation compared with mice with T cells intact. ABSTRACT Ageing of the arteries is characterized by increased large artery stiffness and impaired endothelium-dependent dilatation. T cells contribute to hypertension in acute rodent models but whether they contribute to chronic age-related arterial dysfunction is unknown. To determine whether T cells directly mediate age-related arterial dysfunction, we examined large elastic artery and resistance artery function in young (4-6 months) and old (22-24 months) wild-type mice treated with anti-CD3 F(ab'2) fragments to deplete T cells (150 μg, i.p. every 7 days for 28 days) or isotype control fragments. Old mice exhibited greater numbers of T cells in both aorta and mesenteric vasculature when compared with young mice. Old mice treated with anti-CD3 fragments exhibited depletion of T cells in blood, spleen, aorta and mesenteric vasculature. Old mice also exhibited greater numbers of aortic and mesenteric IFN-γ and TNF-α-producing T cells when compared with young mice. Old control mice exhibited greater large artery stiffness and impaired resistance artery endothelium-dependent dilatation in comparison with young mice. In old mice, large artery stiffness was ameliorated with anti-CD3 treatment. Anti-CD3-treated old mice also exhibited greater endothelium-dependent dilatation than age-matched controls. We also examined arterial function in young and old Rag-1-/- mice, which lack lymphocytes. Rag-1-/- mice exhibited blunted increases in large artery stiffness with age compared with wild-type mice. Old Rag-1-/- mice also exhibited greater endothelium-dependent dilatation compared with old wild-type mice. Collectively, these results demonstrate that T cells play an important role in age-related arterial dysfunction.
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Affiliation(s)
- Daniel W Trott
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Department of Kinesiology, University of Texas at Arlington, Texas, USA
| | - Daniel R Machin
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Tam T T Phuong
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - AdeLola O Adeyemo
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Samuel I Bloom
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA
| | - R Colton Bramwell
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Eric S Sorensen
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA
| | - Lisa A Lesniewski
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,Geriatrics Research Education and Clinical Center, Veteran's Affairs Medical Center, Salt Lake City, Utah, USA
| | - Anthony J Donato
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah, USA.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah, USA.,Geriatrics Research Education and Clinical Center, Veteran's Affairs Medical Center, Salt Lake City, Utah, USA.,Department of Biochemistry, University of Utah, Salt Lake City, Utah, USA
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12
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Yuen LH, Dana S, Liu Y, Bloom SI, Thorsell AG, Neri D, Donato AJ, Kireev D, Schüler H, Franzini RM. Correction to "A Focused DNA-Encoded Chemical Library for the Discovery of Inhibitors of NAD +-Dependent Enzymes". J Am Chem Soc 2021; 143:11272-11273. [PMID: 34270900 DOI: 10.1021/jacs.1c06352] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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13
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Bloom SI, Tuluca A, Ives SJ, Reynolds TH. High-fat diet induced obesity and age influence the telomere shelterin complex and telomerase gene expression in mouse adipose tissue. Physiol Rep 2020; 8:e14461. [PMID: 32512652 PMCID: PMC7280005 DOI: 10.14814/phy2.14461] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Revised: 05/02/2020] [Accepted: 05/03/2020] [Indexed: 12/15/2022] Open
Abstract
Obesity and aging are linked to inflammation and increased risk of chronic disease. Telomeres are the endcaps of chromosomes that are regulated by telomerase, the enzyme that elongates telomeres, as well as a protein complex known as shelterin. Telomere dysfunction is associated with inflammation, aging, and disease. However, the effect of high-fat diet (HFD) induced obesity and advancing age on the shelterin complex and telomerase in adipose tissue is unknown. The present study investigated the effects of obesity and aging on C57BL/6J mice adipose tissue mRNA expression of shelterin complex genes. Young (YG) mice (3 mo) were randomly assigned to be fed either a high-fat diet (YG + HFD; 60% kcal from fat) or a low-fat diet (YG + LFD; 10% kcal from fat). A subset of mice were aged until 16 months. Body weight and epididymal white adipose tissue (EWAT) weight increased with age or a HFD. There was a trend for increased Terf2 expression, as expression was increased in HFD + YG by ~47% and aged mice by ~80%. Pot1b expression was increased in aged mice by ~35%-60% compared to YG, independent of diet. mTert, the gene that codes for the catalytic subunit of telomerase, was significantly elevated in aged mice. Changes in telomere associated gene expression was accompanied by changes in expression of inflammatory markers Mcp1 and Tnfα. These findings suggest obesity and age impact expression of shelterin complex and telomerase related genes in adipose, perhaps altering telomere function in adipose tissue thereby increasing inflammation and risk of chronic disease.
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Affiliation(s)
- Samuel I. Bloom
- Department of Health and Human Physiological SciencesSkidmore CollegeSaratoga SpringsNYUSA
- Department of Nutrition and Integrative PhysiologyUniversity of UtahSalt Lake CityUTUSA
| | - Andrei Tuluca
- Department of Health and Human Physiological SciencesSkidmore CollegeSaratoga SpringsNYUSA
- College of MedicineCentral Michigan UniversityMount PleasantMIUSA
| | - Stephen J. Ives
- Department of Health and Human Physiological SciencesSkidmore CollegeSaratoga SpringsNYUSA
| | - Thomas H. Reynolds
- Department of Health and Human Physiological SciencesSkidmore CollegeSaratoga SpringsNYUSA
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14
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Bloom SI, Islam MT, Tucker JR, Phuong T, Sorensen E, Cai J, Lesniewski LA, Donato AJ. Induction of Telomere Uncapping in Adipocytes Results in Cellular Senescence and Metabolic Dysfunction. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.03353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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15
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Bramwell RC, Bloom SI, Machin DR, Lesniewski LA, Donato AJ. Genetic Reduction of DNA Damage Repair Protein ATM Kinase Attenuates Endothelium‐Dependent Dilation and NO Bioavailability via Enhanced Superoxide in Old but not Young Mice. FASEB J 2020. [DOI: 10.1096/fasebj.2020.34.s1.06559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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16
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Bloom SI, Machin DR, Bramwell RC, Lesniewski LA, Donato AJ. Genetic deletion of the DNA damage repair protein, ATM kinase, is not sufficient to induce vascular dysfunction in young mice. FASEB J 2019. [DOI: 10.1096/fasebj.2019.33.1_supplement.596.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Samuel I Bloom
- Nutrition and Integrative PhysiologyUniversity of UtahSalt Lake CityUT
| | | | | | - Lisa A Lesniewski
- Nutrition and Integrative PhysiologyUniversity of UtahSalt Lake CityUT
- Internal MedicineUniversity of UtahSalt Lake CityUT
- Geriatric Research, Education, and Clinical CenterSalt Lake City Veterans Affairs Medical CenterSalt Lake CityUT
| | - Anthony J Donato
- Nutrition and Integrative PhysiologyUniversity of UtahSalt Lake CityUT
- Internal MedicineUniversity of UtahSalt Lake CityUT
- BiochemistryUniversity of UtahSalt Lake CityUT
- Geriatric Research, Education, and Clinical CenterSalt Lake City Veterans Affairs Medical CenterSalt Lake CityUT
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17
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Yuen LH, Dana S, Liu Y, Bloom SI, Thorsell AG, Neri D, Donato AJ, Kireev D, Schüler H, Franzini RM. A Focused DNA-Encoded Chemical Library for the Discovery of Inhibitors of NAD+-Dependent Enzymes. J Am Chem Soc 2019; 141:5169-5181. [DOI: 10.1021/jacs.8b08039] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Lik Hang Yuen
- Department of Medicinal Chemistry, University of Utah, 30 S 2000 E, Salt Lake City, Utah 84112, United States
| | - Srikanta Dana
- Department of Medicinal Chemistry, University of Utah, 30 S 2000 E, Salt Lake City, Utah 84112, United States
| | - Yu Liu
- Department of Internal Medicine, University of Utah, 500 Foothill Drive, Salt Lake City, Utah 84148, United States
| | - Samuel I. Bloom
- Department of Internal Medicine, University of Utah, 500 Foothill Drive, Salt Lake City, Utah 84148, United States
| | - Ann-Gerd Thorsell
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 7c, 14157 Huddinge, Sweden
| | - Dario Neri
- Department of Pharmaceutical Sciences, ETH Zürich, Vladimir Prelog Weg 3, 8093 Zürich, Switzerland
| | - Anthony J. Donato
- Department of Internal Medicine, University of Utah, 500 Foothill Drive, Salt Lake City, Utah 84148, United States
| | - Dmitri Kireev
- Center for Integrative Chemical Biology and Drug Discovery, UNC Eshelman School of Pharmacy, University of North Carolina, Chapel Hill, North Carolina 27599, United States
| | - Herwig Schüler
- Department of Biosciences and Nutrition, Karolinska Institutet, Hälsovägen 7c, 14157 Huddinge, Sweden
| | - Raphael M. Franzini
- Department of Medicinal Chemistry, University of Utah, 30 S 2000 E, Salt Lake City, Utah 84112, United States
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18
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Morgan RG, Walker AE, Trott DW, Machin DR, Henson GD, Reihl KD, Cawthon RM, Denchi EL, Liu Y, Bloom SI, Phuong TT, Richardson RS, Lesniewski LA, Donato AJ. Induced Trf2 deletion leads to aging vascular phenotype in mice associated with arterial telomere uncapping, senescence signaling, and oxidative stress. J Mol Cell Cardiol 2018; 127:74-82. [PMID: 30502348 DOI: 10.1016/j.yjmcc.2018.11.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 10/18/2018] [Accepted: 11/21/2018] [Indexed: 12/19/2022]
Abstract
Age-related vascular dysfunction in large elastic and resistance arteries is associated with reductions in microvascular perfusion and elevations in blood pressure. Recent evidence indicates that telomere uncapping-induced senescence in vascular cells may be an important source of oxidative stress and vascular dysfunction in aging, but the causal relationship between these processes has yet to be elucidated. To test this important unexplored hypothesis, we measured arterial senescence signaling and oxidative stress, carotid and mesenteric artery endothelium-dependent vasodilatory capacity, markers of mesenteric microvascular perfusion and endothelial glycocalyx deterioration, and blood pressure in a novel mouse model of Cre-inducible whole body Trf2 deletion and telomere uncapping. Trf2 deletion led to a 320% increase in arterial senescence signaling (P < .05). There was a concurrent 29% and 22% reduction in peak endothelium-dependent vasodilation in carotid and mesenteric arteries, respectively, as well as a 63% reduction in mesenteric microvascular endothelial glycocalyx thickness (all P ≤ .01). Mesenteric microvascular perfusion was reduced by 8% and systolic blood pressure was increased by 9% following Trf2 deletion (both P < .05). Trf2 deletion also led to a pro-oxidative arterial phenotype characterized by increased in NADPH oxidase gene expression; a 210% increase in superoxide levels that was partly dependent on NADPH oxidase activity; and an oxidative stress mediated reduction in carotid artery vasodilation (all P ≤ .05). Collectively, our findings demonstrate that induced Trf2 deletion leads to telomere uncapping, increased senescence signaling, and oxidative stress mediated functional impairments in the vasculature similar to those seen in human aging.
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Affiliation(s)
- R Garrett Morgan
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Ashley E Walker
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA
| | - Daniel W Trott
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA
| | - Daniel R Machin
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA
| | - Grant D Henson
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA; Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Kelly D Reihl
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA
| | - Richard M Cawthon
- Department of Human Genetics, University of Utah, Salt Lake City, UT, USA
| | - Eros L Denchi
- Department of Molecular and Experimental Medicine, The Scripps Research Institute, La Jolla, CA, USA
| | - Yu Liu
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, University of Utah, Salt Lake City, UT, USA; Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Samuel I Bloom
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Tam T Phuong
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, University of Utah, Salt Lake City, UT, USA
| | - Russell S Richardson
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA; Department of Exercise and Sport Science, University of Utah, Salt Lake City, UT, USA
| | - Lisa A Lesniewski
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA
| | - Anthony J Donato
- Division of Geriatrics, Department of Internal Medicine, University of Utah School of Medicine, University of Utah, Salt Lake City, UT, USA; Geriatric Research, Education, and Clinical Center, George E. Wahlen Department of Veterans Affairs Medical Center, Salt Lake City, UT, USA; Department of Biochemistry, University of Utah, Salt Lake City, UT, USA; Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA.
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19
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Frech TM, Machin DR, Murtaugh MA, Stoddard GJ, Bloom SI, Phibbs JV, Donato AJ. Implications of endothelial shear stress on systemic sclerosis vasculopathy and treatment. Clin Exp Rheumatol 2018. [DOI: 10.55563/clinexprheumatol/7ulgbj] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Affiliation(s)
- Tracy M. Frech
- University of Utah, Department of Internal Medicine; University of Utah Hospitals and Clinics; and VAMC Salt Lake City, GRECC, Salt Lake City, UT, USA.
| | - Daniel R. Machin
- University of Utah, Department of Internal Medicine, Salt Lake City, UT, USA
| | - Maureen A. Murtaugh
- University of Utah, Department of Internal Medicine, Salt Lake City, UT, USA
| | - Gregory J. Stoddard
- University of Utah, Department of Internal Medicine, Salt Lake City, UT, USA
| | - Samuel I. Bloom
- University of Utah, Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | | | - Anthony J. Donato
- University of Utah, Department of Internal Medicine; University of Utah, Department of Exercise and Sport Science; University of Utah, Dept. of Nutrition and Integrative Physiology, University of Utah; and VAMC Salt Lake City, GRECC, Salt Lake City, USA
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20
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Liu Y, Bloom SI, Donato AJ. The role of senescence, telomere dysfunction and shelterin in vascular aging. Microcirculation 2018; 26:e12487. [PMID: 29924435 DOI: 10.1111/micc.12487] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Accepted: 06/18/2018] [Indexed: 12/11/2022]
Abstract
In the United States and other westernized nations, CVDs are the leading cause of death in adults over 65 years of age. Large artery stiffness and endothelial dysfunction are increased with age and age-associated arterial dysfunction is an important antecedent of CVDs. One age-associated change that may contribute to vascular dysfunction and CVD risk is an increase in the number of resident senescent cells in the vasculature. Senescent cells display a pro-oxidant, pro-inflammatory phenotype known as the SASP. However, the mechanisms that drive the SASP and the vascular aging phenotype remain elusive. A putative mechanism is the involvement of oxidative stress and inflammation in telomere function. Telomeres are the end caps of chromosomes which are maintained by a six-protein complex known as shelterin. Disruption of shelterin can uncap telomeres and induce cellular senescence. Accordingly, in this review, we propose that oxidative stress and inflammation disrupt shelterin in vascular cells, driving telomere dysfunction and that this mechanism may be responsible for the induction of SASP. The proposed mechanisms may represent some of the initial changes that lead to vascular dysfunction in advanced age.
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Affiliation(s)
- Yu Liu
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah.,Department of Geriatrics, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Samuel I Bloom
- Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Anthony J Donato
- Department of Internal Medicine, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah.,Department of Biochemistry, University of Utah, Salt Lake City, Utah.,Geriatrics Research Education and Clinical Center, Veteran's Affairs Medical Center, Salt Lake City, Utah
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21
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Frech TM, Machin DR, Murtaugh MA, Stoddard GJ, Bloom SI, Phibbs JV, Donato AJ. Implications of endothelial shear stress on systemic sclerosis vasculopathy and treatment. Clin Exp Rheumatol 2018; 36 Suppl 113:175-182. [PMID: 30277867 PMCID: PMC6542469] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 07/30/2018] [Indexed: 02/16/2023]
Abstract
There are no Federal Drug Administration approved drugs for the treatment of systemic sclerosis vascular digital ulcers (DU) in the United States, which are thought to be an end-stage result of prolonged ischaemia due to severe, prolonged Raynaud's phenomenon. Most therapeutics for vasodilation used in SSc work different pathways to target the smooth muscle to induce vessel relaxation. Longitudinal studies of vascular function allow insight into the effects of medications used for Raynaud's phenomenon in the SSc patient population. In this review, we discuss vascular tone, the function of the endothelium in SSc, and provide the rationale for longitudinal studies of vascular function and therapeutics that target the endothelial shear stress in addition to vasodilation for treatment and prevention of DU. This review provides the rationale for vasodilatory medication use for treatment of SSc-related DU and justifies access to non-FDA approved medications for this indication.
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Affiliation(s)
- Tracy M Frech
- University of Utah, Department of Internal Medicine; University of Utah Hospitals and Clinics; and VAMC Salt Lake City, GRECC, Salt Lake City, UT, USA.
| | - Daniel R Machin
- University of Utah, Department of Internal Medicine, Salt Lake City, UT, USA
| | - Maureen A Murtaugh
- University of Utah, Department of Internal Medicine, Salt Lake City, UT, USA
| | - Gregory J Stoddard
- University of Utah, Department of Internal Medicine, Salt Lake City, UT, USA
| | - Samuel I Bloom
- University of Utah, Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, UT, USA
| | - Jessica V Phibbs
- University of Utah Hospitals and Clinics, Salt Lake City, UT, USA
| | - Anthony J Donato
- University of Utah, Department of Internal Medicine; University of Utah, Department of Exercise and Sport Science; University of Utah, Dept. of Nutrition and Integrative Physiology, University of Utah; and VAMC Salt Lake City, GRECC, Salt Lake City, USA
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22
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Machin DR, Bloom SI, Campbell RA, Phuong TTT, Gates PE, Lesniewski LA, Rondina MT, Donato AJ. Advanced age results in a diminished endothelial glycocalyx. Am J Physiol Heart Circ Physiol 2018; 315:H531-H539. [PMID: 29750566 DOI: 10.1152/ajpheart.00104.2018] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Age-related microvascular dysfunction is well characterized in rodents and humans, but little is known about the properties of the microvascular endothelial glycocalyx in advanced age. We examined the glycocalyx in microvessels of young and old male C57BL6 mice (young: 6.1 ± 0.1 mo vs. old: 24.6 ± 0.2 mo) using intravital microscopy and transmission electron microscopy and in human participants (young: 29 ± 1 yr vs. old: 60 ± 2 yr) using intravital microscopy. Glycocalyx thickness in mesenteric and skeletal muscle microvessels was 51-54% lower in old compared with young mice. We also observed 33% lower glycocalyx thickness in the sublingual microcirculation of humans in advanced age. The perfused boundary region, a marker of glycocalyx barrier function, was also obtained using an automated capture and analysis system. In advanced age, we observed a 10-22% greater perfused boundary region in mice and humans, indicating a more penetrable glycocalyx. Finally, using this automated analysis system, we examined perfused microvascular density and red blood cell (RBC) fraction. Perfused microvascular density is a marker of microvascular function that reflects the length of perfused microvessel segments in a given area; RBC fraction represents the heterogeneity in RBC presence between microvessel segments. Compared with young, the perfused microvascular density was 16-21% lower and RBC fraction was 5-14% lower in older mice and in older humans. These data provide novel evidence that, across mammalian species, a diminished glycocalyx is present in advanced age and is accompanied by markers of impaired microvascular perfusion. Age-related glycocalyx deterioration may be an important contributor to microvascular dysfunction in older adults and subsequent pathophysiology. NEW & NOTEWORTHY Advanced age is characterized by microvascular dysfunction that contributes to age-related cardiovascular diseases, but little is known about endothelial glycocalyx properties in advanced age. This study reveals, for the first time, lower glycocalyx thickness and barrier function that is accompanied by impaired microvascular perfusion in both mice and humans in advanced age.
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Affiliation(s)
- Daniel R Machin
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Salt Lake City, Salt Lake City, Utah.,Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Samuel I Bloom
- Department of Nutrition and Integrative Physiology, University of Utah , Salt Lake City, Utah
| | - Robert A Campbell
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah.,Molecular Medicine, University of Utah , Salt Lake City, Utah
| | - Tam T T Phuong
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Phillip E Gates
- Department of Internal Medicine, University of Utah , Salt Lake City, Utah
| | - Lisa A Lesniewski
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Salt Lake City, Salt Lake City, Utah.,Department of Internal Medicine, University of Utah , Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah , Salt Lake City, Utah
| | - Matthew T Rondina
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Salt Lake City, Salt Lake City, Utah.,Department of Internal Medicine, University of Utah , Salt Lake City, Utah.,Molecular Medicine, University of Utah , Salt Lake City, Utah
| | - Anthony J Donato
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Salt Lake City, Salt Lake City, Utah.,Department of Internal Medicine, University of Utah , Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah , Salt Lake City, Utah.,Department of Biochemistry, University of Utah , Salt Lake City, Utah
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Bloom SI, Matias AA, Morrow N, Martins N, Roh Y, Ebenstein D, O’Brien G, Escudero D, Brito K, Glickman L, Ives SJ, Arciero PJ. Effects Of A Combined Protein And Antioxidant Supplement On Muscle Recovery In College - Aged Males. Med Sci Sports Exerc 2017. [DOI: 10.1249/01.mss.0000517049.27694.f9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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24
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Schuch RJ, Bloom SI, Gannett D, McEneaney B. Risk management and physician characteristics in a preferred provider organization credentialing program. J Ambul Care Manage 1991; 14:58-65. [PMID: 10108695 DOI: 10.1097/00004479-199101000-00008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Affiliation(s)
- R J Schuch
- College of Medicine, University of Illinois at Chicago
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