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Liang M, Lyu ZS, Zhang YY, Tang SQ, Xing T, Chen YH, Wang Y, Jiang Q, Xu LP, Zhang XH, Huang XJ, Kong Y. Activation of PPARδ in bone marrow endothelial progenitor cells improves their hematopoiesis-supporting ability after myelosuppressive injury. Cancer Lett 2024; 592:216937. [PMID: 38704134 DOI: 10.1016/j.canlet.2024.216937] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/30/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024]
Abstract
Dysfunctional bone marrow (BM) endothelial progenitor cells (EPCs) with high levels of reactive oxygen species (ROS) are responsible for defective hematopoiesis in poor graft function (PGF) patients with acute leukemia or myelodysplastic neoplasms post-allotransplant. However, the underlying mechanism by which BM EPCs regulate their intracellular ROS levels and the capacity to support hematopoiesis have not been well clarified. Herein, we demonstrated decreased levels of peroxisome proliferator-activated receptor delta (PPARδ), a lipid-activated nuclear receptor, in BM EPCs of PGF patients compared with those with good graft function (GGF). In vitro assays further identified that PPARδ knockdown contributed to reduced and dysfunctional BM EPCs, characterized by the impaired ability to support hematopoiesis, which were restored by PPARδ overexpression. Moreover, GW501516, an agonist of PPARδ, repaired the damaged BM EPCs triggered by 5-fluorouracil (5FU) in vitro and in vivo. Clinically, activation of PPARδ by GW501516 benefited the damaged BM EPCs from PGF patients or acute leukemia patients in complete remission (CR) post-chemotherapy. Mechanistically, we found that increased expression of NADPH oxidases (NOXs), the main ROS-generating enzymes, may lead to elevated ROS level in BM EPCs, and insufficient PPARδ may trigger BM EPC damage via ROS/p53 pathway. Collectively, we found that defective PPARδ contributes to BM EPC dysfunction, whereas activation of PPARδ in BM EPCs improves their hematopoiesis-supporting ability after myelosuppressive therapy, which may provide a potential therapeutic target not only for patients with leukemia but also for those with other cancers.
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Affiliation(s)
- Mi Liang
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Collaborative Innovation Center of Hematology, Peking University, Beijing, China
| | - Zhong-Shi Lyu
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Collaborative Innovation Center of Hematology, Peking University, Beijing, China
| | - Yuan-Yuan Zhang
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Collaborative Innovation Center of Hematology, Peking University, Beijing, China.
| | - Shu-Qian Tang
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Collaborative Innovation Center of Hematology, Peking University, Beijing, China
| | - Tong Xing
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Collaborative Innovation Center of Hematology, Peking University, Beijing, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Yu-Hong Chen
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Collaborative Innovation Center of Hematology, Peking University, Beijing, China
| | - Yu Wang
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Collaborative Innovation Center of Hematology, Peking University, Beijing, China
| | - Qian Jiang
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Collaborative Innovation Center of Hematology, Peking University, Beijing, China
| | - Lan-Ping Xu
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Collaborative Innovation Center of Hematology, Peking University, Beijing, China
| | - Xiao-Hui Zhang
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Collaborative Innovation Center of Hematology, Peking University, Beijing, China
| | - Xiao-Jun Huang
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Collaborative Innovation Center of Hematology, Peking University, Beijing, China; Peking-Tsinghua Center for Life Sciences, Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China; State Key Laboratory of Natural and Biomimetic Drugs, China.
| | - Yuan Kong
- Peking University People's Hospital, Peking University Institute of Hematology, National Clinical Research Center for Hematologic Disease, Beijing Key Laboratory of Hematopoietic Stem Cell Transplantation, Collaborative Innovation Center of Hematology, Peking University, Beijing, China.
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He T, d’Uscio LV, Katusic ZS. BACE2 deficiency impairs expression and function of endothelial nitric oxide synthase in brain endothelial cells. J Neurochem 2023; 166:928-942. [PMID: 37547981 PMCID: PMC10599353 DOI: 10.1111/jnc.15929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 07/14/2023] [Accepted: 07/22/2023] [Indexed: 08/08/2023]
Abstract
Beta-site amyloid precursor protein (APP)-cleaving enzyme 2 (BACE2) is highly expressed in cerebrovascular endothelium. Notably, BACE2 is one of the most downregulated genes in cerebrovascular endothelium derived from patients with Alzheimer's disease. The present study was designed to determine the role of BACE2 in control of expression and function of endothelial nitric oxide synthase (eNOS). Genetic downregulation of BACE2 with small interfering RNA (BACE2siRNA) in human brain microvascular endothelial cells (BMECs) significantly decreased expression of eNOS and elevated levels of eNOS phosphorylated at threonine residue Thr495, thus leading to reduced production of nitric oxide (NO). BACE2siRNA also suppressed expression of APP and decreased production and release of soluble APPα (sAPPα). In contrast, adenovirus-mediated overexpression of APP increased expression of eNOS. Consistent with these observations, nanomolar concentrations of sAPPα and APP 17mer peptide (derived from sAPPα) augmented eNOS expression. Further analysis established that γ-aminobutyric acid type B receptor subunit 1 and Krüppel-like factor 2 may function as downstream molecular targets significantly contributing to BACE2/APP/sAPPα-induced up-regulation of eNOS. In agreement with studies on cultured human endothelium, endothelium-dependent relaxations to acetylcholine and basal production of cyclic GMP were impaired in cerebral arteries of BACE2-deficient mice. We propose that in the brain blood vessels, BACE2 may function as a vascular protective protein.
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Affiliation(s)
- Tongrong He
- Departments of Anesthesiology and Perioperative Medicine, and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Livius V. d’Uscio
- Departments of Anesthesiology and Perioperative Medicine, and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
| | - Zvonimir S. Katusic
- Departments of Anesthesiology and Perioperative Medicine, and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic, Rochester, MN, USA
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Liu J, Du X, Yao Q, Jiang T, Cui Q, Xie X, Zhao Z, Lai B, Wang N, Xiao L. Procyanidin B2 ameliorates endothelial dysfunction induced by nicotine via the induction of tetrahydrobiopterin synthesis. J Funct Foods 2022. [DOI: 10.1016/j.jff.2022.105306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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Xiao L, Wang N. PPAR-δ: A key nuclear receptor in vascular function and remodeling. J Mol Cell Cardiol 2022; 169:1-9. [DOI: 10.1016/j.yjmcc.2022.04.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 03/29/2022] [Accepted: 04/25/2022] [Indexed: 12/08/2022]
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Pergialiotis V, Frountzas M, Fasoulakis Z, Daskalakis G, Chrisochoidi M, Kontzoglou K, Perrea DN. Peroxisome Proliferator-Activated Receptor Alpha (PPAR-α) as a Regulator of the Angiogenic Profile of Endometriotic Lesions. Cureus 2022; 14:e22616. [PMID: 35371629 PMCID: PMC8958147 DOI: 10.7759/cureus.22616] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/25/2022] [Indexed: 11/24/2022] Open
Abstract
Endometriosis is a disease that affects a significant proportion of women and its infiltrative pattern is entirely dependent on the vascular supply of lesions. Several factors seem to trigger the process of angiogenesis in endometriotic lesions. During the last years, peroxisome proliferator-activated receptors (PPARs), a group of nuclear proteins that regulate gene transcription and that seem to regulate energy consumption and expenditure, have been also implicated in the pathophysiology of angiogenesis. Their ability to regulate the course of cancer and improve the survival rates of patients has been extensively studied and seems to be partially dependent on alteration of the vascular supply of malignant lesions. Research in the field of endometriosis is scarce in the international literature and mainly focused on PPAR-gamma. However, indirect evidence suggests that PPAR-alpha (PPAR-α) may also regulate the vascular supply of endometriotic lesions as well. Specifically, PPAR-α agonists seem to downregulate angiogenesis by increasing the expression of several anti-angiogenic molecules, including thrombospondin-1 (TSP-1) and gypenoside 140 (gp140), as well as factors that are involved in the mitogen-activated protein kinase cascade. In the present article, we summarize existing indirect and direct evidence that indicates the existence of an association between the expression of PPAR-α and endometriosis to help future research in this field.
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Kadayat TM, Shrestha A, Jeon YH, An H, Kim J, Cho SJ, Chin J. Targeting Peroxisome Proliferator-Activated Receptor Delta (PPARδ): A Medicinal Chemistry Perspective. J Med Chem 2020; 63:10109-10134. [DOI: 10.1021/acs.jmedchem.9b01882] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Tara Man Kadayat
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu 41061, Republic of Korea
| | - Aarajana Shrestha
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu 41061, Republic of Korea
- College of Pharmacy, Yeungnam University, Gyeongsan 38541, Republic of Korea
| | - Yong Hyun Jeon
- Laboratory Animal Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu 41061, Republic of Korea
- Leading-edge Research Center for Drug Discovery and Development for Diabetes and Metabolic Disease, Kyungpook National University Hospital, Daegu 41404, Republic of Korea
| | - Hongchan An
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu 41061, Republic of Korea
| | - Jina Kim
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu 41061, Republic of Korea
| | - Sung Jin Cho
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu 41061, Republic of Korea
- Leading-edge Research Center for Drug Discovery and Development for Diabetes and Metabolic Disease, Kyungpook National University Hospital, Daegu 41404, Republic of Korea
| | - Jungwook Chin
- New Drug Development Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu 41061, Republic of Korea
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Shear Stress Triggers Angiogenesis of Late Endothelial Progenitor Cells via the PTEN/Akt/GTPCH/BH4 Pathway. Stem Cells Int 2020; 2020:5939530. [PMID: 32399044 PMCID: PMC7210539 DOI: 10.1155/2020/5939530] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 11/03/2019] [Accepted: 11/12/2019] [Indexed: 02/07/2023] Open
Abstract
Background Shear stress is an effective modulator of endothelial progenitor cells (EPCs) and has been suggested to play an important role in angiogenesis. The phosphatase and tensin homolog (PTEN)/Akt and guanosine triphosphate cyclohydrolase (GTPCH)/tetrahydrobiopterin (BH4) pathways regulate the function of early EPCs. However, the role of these pathways in the shear stress-induced angiogenesis of late EPCs remains poorly understood. Therefore, we aim to investigate whether shear stress could upregulate the angiogenesis capacity of late EPCs and to further explore the possible underlying mechanisms. Methods Late EPCs were subjected to laminar shear stress (LSS), and their in vitro migration, proliferation, and tube formation capacity were determined. In addition, the in vivo angiogenesis capacity was explored, along with the expression of molecules involved in the PTEN/Akt and GTPCH/BH4 pathways. Results LSS elevated the in vitro activities of late EPCs, which were accompanied by downregulated PTEN expression, accelerated Akt phosphorylation, and GTPCH/BH4 pathway activation (all P < 0.05). Following Akt inhibition, LSS-induced upregulated GTPCH expression, BH4, and NO level of EPCs were suppressed. LSS significantly improved the migration, proliferation, and tube formation ability (15 dyn/cm2 LSS vs. stationary: 72.2 ± 5.5 vs. 47.3 ± 7.3, 0.517 ± 0.05 vs. 0.367 ± 0.038, and 1.664 ± 0.315 vs. 1 ± 0, respectively; all P < 0.05) along with the in vivo angiogenesis capacity of late EPCs, contributing to the recovery of limb ischemia. These effects were also blocked by Akt inhibition or GTPCH knockdown (P < 0.05, respectively). Conclusions This study provides the first evidence that shear stress triggers angiogenesis in late EPCs via the PTEN/Akt/GTPCH/BH4 pathway, providing a potential nonpharmacologic therapeutic strategy for promoting angiogenesis in ischemia-related diseases.
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Zhang Z, Xie X, Yao Q, Liu J, Tian Y, Yang C, Xiao L, Wang N. PPARδ agonist prevents endothelial dysfunction via induction of dihydrofolate reductase gene and activation of tetrahydrobiopterin salvage pathway. Br J Pharmacol 2019; 176:2945-2961. [PMID: 31144304 PMCID: PMC6637045 DOI: 10.1111/bph.14745] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 04/10/2019] [Accepted: 05/08/2019] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND AND PURPOSE Impaired endothelium-dependent relaxation (EDR) is a hallmark of endothelial dysfunction. A deficiency of tetrahydrobiopterin (BH4 ) causes endothelial NOS to produce ROS rather than NO. PPARδ is an emerging target for pharmacological intervention of endothelial dysfunction. Thus, the present study examined the role of PPARδ in the regulation of dihydrofolate reductase (DHFR), a key enzyme in the BH4 salvage pathway. EXPERIMENTAL APPROACH Gene expression was measured by using qRT-PCR and western blotting. Biopterins and ROS were determined by using HPLC. NO was measured with fluorescent dye and electron paramagnetic resonance spectroscopy. Vasorelaxation was measured by Multi Myograph System. KEY RESULTS The PPARδ agonist GW501516 increased DHFR and BH4 levels in endothelial cells (ECs). The effect was blocked by PPARδ antagonist GSK0660. Chromatin immunoprecipitation identified PPAR-responsive elements within the 5'-flanking region of the human DHFR gene. The promoter activity was examined with luciferase assays using deletion reporters. Importantly, DHFR expression was suppressed by palmitic acid (PA, a saturated fatty acid) but increased by docosahexaenoic acid (DHA, a polyunsaturated fatty acid). GSK0660 prevented DHA-induced increased DHFR expression. Conversely, the suppressive effect of PA was mitigated by GW501516. In mouse aortae, GW501516 ameliorated the PA-impaired EDR. However, this vasoprotective effect was attenuated by DHFR siRNA or methotrexate. In EC-specific Ppard knockout mice, GW501516 failed to improve vasorelaxation. CONCLUSION AND IMPLICATIONS PPARδ prevented endothelial dysfunction by increasing DHFR and activating the BH4 salvage pathway. These results provide a novel mechanism for the protective roles of PPARδ against vascular diseases.
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Affiliation(s)
- Zihui Zhang
- Cardiovascular Research Center, School of Basic Medical SciencesXi'an Jiaotong UniversityXi'anChina
| | - Xinya Xie
- Cardiovascular Research Center, School of Basic Medical SciencesXi'an Jiaotong UniversityXi'anChina
| | - Qinyu Yao
- Cardiovascular Research Center, School of Basic Medical SciencesXi'an Jiaotong UniversityXi'anChina
| | - Jia Liu
- Cardiovascular Research Center, School of Basic Medical SciencesXi'an Jiaotong UniversityXi'anChina
| | - Ying Tian
- Cardiovascular Research Center, School of Basic Medical SciencesXi'an Jiaotong UniversityXi'anChina
| | - Chunmiao Yang
- Cardiovascular Research Center, School of Basic Medical SciencesXi'an Jiaotong UniversityXi'anChina
| | - Lei Xiao
- Cardiovascular Research Center, School of Basic Medical SciencesXi'an Jiaotong UniversityXi'anChina
| | - Nanping Wang
- The Advanced Institute for Medical SciencesDalian Medical UniversityDalianChina
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6-Gingerol Normalizes the Expression of Biomarkers Related to Hypertension via PPAR δ in HUVECs, HEK293, and Differentiated 3T3-L1 Cells. PPAR Res 2018; 2018:6485064. [PMID: 30643517 PMCID: PMC6311252 DOI: 10.1155/2018/6485064] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Revised: 11/04/2018] [Accepted: 12/05/2018] [Indexed: 12/21/2022] Open
Abstract
Hypertension is a disease with a high prevalence and high mortality rates worldwide. In addition, various factors, such as genetic predisposition, lifestyle factors, and the abnormality of organs related to blood pressure, are involved in the development of hypertension. However, at present, there are few available drugs for hypertension that do not induce side effects. Although the therapeutic effects of ginger on hypertension are well established, the precise mechanism has not been elucidated. Therefore, this study was designed to evaluate the antihypertensive mechanism of 6-gingerol, one of the main ingredients of ginger, and to assist in the development of new drugs for hypertension without side effects. The antihypertensive effects and mechanism of 6-gingerol were identified through reverse transcription polymerase chain reaction (RT-PCR), western blotting, and immunocytochemical staining for biomarkers involved in hypertension in human umbilical vein endothelial cells (HUVECs), human embryonal kidney cells (HEK293 cells), and mouse preadipocytes (3T3-L1 cells). The lipid accumulation in differentiated 3T3-L1 cells was evaluated by using Oil Red O staining. 6- Gingerol increased the level of phosphorylated endothelial nitric oxide synthase (eNOS) protein but decreased that of vascular cell adhesion protein 1 (VCAM1) and tumor necrosis factor alpha (TNFα) in HUVECs. In HEK293 cells, the expression of the epithelial sodium channel (ENaC) protein was reduced by 6-gingerol. Lipid accumulation was attenuated by 6-gingerol treatment in differentiated 3T3-L1 cells. These effects were regulated via peroxisome proliferator-activated receptor delta (PPARδ). 6-Gingerol ameliorated the expression of biomarkers involved in the development of hypertension through PPARδ in HUVECs, HEK293, and differentiated 3T3-L1 cells.
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PPARβ/δ: Linking Metabolism to Regeneration. Int J Mol Sci 2018; 19:ijms19072013. [PMID: 29996502 PMCID: PMC6073704 DOI: 10.3390/ijms19072013] [Citation(s) in RCA: 61] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 06/29/2018] [Accepted: 07/05/2018] [Indexed: 01/10/2023] Open
Abstract
In contrast to the general belief that regeneration is a rare event, mainly occurring in simple organisms, the ability of regeneration is widely distributed in the animal kingdom. Yet, the efficiency and extent of regeneration varies greatly. Humans can recover from blood loss as well as damage to tissues like bone and liver. Yet damage to the heart and brain cannot be reversed, resulting in scaring. Thus, there is a great interest in understanding the molecular mechanisms of naturally occurring regeneration and to apply this knowledge to repair human organs. During regeneration, injury-activated immune cells induce wound healing, extracellular matrix remodeling, migration, dedifferentiation and/or proliferation with subsequent differentiation of somatic or stem cells. An anti-inflammatory response stops the regenerative process, which ends with tissue remodeling to achieve the original functional state. Notably, many of these processes are associated with enhanced glycolysis. Therefore, peroxisome proliferator-activated receptor (PPAR) β/δ—which is known to be involved for example in lipid catabolism, glucose homeostasis, inflammation, survival, proliferation, differentiation, as well as mammalian regeneration of the skin, bone and liver—appears to be a promising target to promote mammalian regeneration. This review summarizes our current knowledge of PPARβ/δ in processes associated with wound healing and regeneration.
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Shear stress: An essential driver of endothelial progenitor cells. J Mol Cell Cardiol 2018; 118:46-69. [PMID: 29549046 DOI: 10.1016/j.yjmcc.2018.03.007] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2018] [Revised: 03/08/2018] [Accepted: 03/09/2018] [Indexed: 02/06/2023]
Abstract
The blood flow through vessels produces a tangential, or shear, stress sensed by their innermost layer (i.e., endothelium) and representing a major hemodynamic force. In humans, endothelial repair and blood vessel formation are mainly performed by circulating endothelial progenitor cells (EPCs) characterized by a considerable expression of vascular endothelial growth factor receptor 2 (VEGFR2), CD34, and CD133, pronounced tube formation activity in vitro, and strong reendothelialization or neovascularization capacity in vivo. EPCs have been proposed as a promising agent to induce reendothelialization of injured arteries, neovascularization of ischemic tissues, and endothelialization or vascularization of bioartificial constructs. A number of preconditioning approaches have been suggested to improve the regenerative potential of EPCs, including the use of biophysical stimuli such as shear stress. However, in spite of well-defined influence of shear stress on mature endothelial cells (ECs), articles summarizing how it affects EPCs are lacking. Here we discuss the impact of shear stress on homing, paracrine effects, and differentiation of EPCs. Unidirectional laminar shear stress significantly promotes homing of circulating EPCs to endothelial injury sites, induces anti-thrombotic and anti-atherosclerotic phenotype of EPCs, increases their capability to form capillary-like tubes in vitro, and enhances differentiation of EPCs into mature ECs in a dose-dependent manner. These effects are mediated by VEGFR2, Tie2, Notch, and β1/3 integrin signaling and can be abrogated by means of complementary siRNA/shRNA or selective pharmacological inhibitors of the respective proteins. Although the testing of sheared EPCs for vascular tissue engineering or regenerative medicine applications is still an unaccomplished task, favorable effects of unidirectional laminar shear stress on EPCs suggest its usefulness for their preconditioning.
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Maccallini C, Mollica A, Amoroso R. The Positive Regulation of eNOS Signaling by PPAR Agonists in Cardiovascular Diseases. Am J Cardiovasc Drugs 2017; 17:273-281. [PMID: 28315197 DOI: 10.1007/s40256-017-0220-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Increasing evidence shows that activation of peroxisome proliferator-activated receptors (PPARs) plays an essential role in the regulation of vascular endothelial function through a range of mechanisms, including non-metabolic. Among these, the PPAR-mediated activation of endothelial nitric oxide synthase (eNOS) appears to be of considerable importance. The regulated and sustained bioavailability of nitric oxide (NO) in the endothelium is essential to avoid the development of cardiovascular diseases such as hypertension or atherosclerosis. Therefore, a deeper understanding of the different effects of specific PPAR ligands on NO bioavailability could be useful in the development of novel or multi-targeted PPAR agonists. In this review, we report the most meaningful and up-to-date in vitro and in vivo studies of the regulation of NO production performed by different PPAR agonists. Insights into the molecular mechanisms of PPAR-mediated eNOS activation are also provided. Although findings from animal studies in which the activation of PPARα, PPARβ/δ, or PPARγ have provided clear vasoprotective effects have been promising, several benefits from PPAR agonists are offset by unwanted outcomes. Therefore, new insights could be useful in the development of tissue-targeted PPAR agonists with more tolerable side effects to improve treatment options for cardiovascular diseases.
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Magadum A, Ding Y, He L, Kim T, Vasudevarao MD, Long Q, Yang K, Wickramasinghe N, Renikunta HV, Dubois N, Weidinger G, Yang Q, Engel FB. Live cell screening platform identifies PPARδ as a regulator of cardiomyocyte proliferation and cardiac repair. Cell Res 2017; 27:1002-1019. [PMID: 28621328 PMCID: PMC5539351 DOI: 10.1038/cr.2017.84] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Revised: 05/05/2017] [Accepted: 05/08/2017] [Indexed: 12/15/2022] Open
Abstract
Zebrafish can efficiently regenerate their heart through cardiomyocyte proliferation. In contrast, mammalian cardiomyocytes stop proliferating shortly after birth, limiting the regenerative capacity of the postnatal mammalian heart. Therefore, if the endogenous potential of postnatal cardiomyocyte proliferation could be enhanced, it could offer a promising future therapy for heart failure patients. Here, we set out to systematically identify small molecules triggering postnatal cardiomyocyte proliferation. By screening chemical compound libraries utilizing a Fucci-based system for assessing cell cycle stages, we identified carbacyclin as an inducer of postnatal cardiomyocyte proliferation. In vitro, carbacyclin induced proliferation of neonatal and adult mononuclear rat cardiomyocytes via a peroxisome proliferator-activated receptor δ (PPARδ)/PDK1/p308Akt/GSK3β/β-catenin pathway. Inhibition of PPARδ reduced cardiomyocyte proliferation during zebrafish heart regeneration. Notably, inducible cardiomyocyte-specific overexpression of constitutively active PPARδ as well as treatment with PPARδ agonist after myocardial infarction in mice induced cell cycle progression in cardiomyocytes, reduced scarring, and improved cardiac function. Collectively, we established a cardiomyocyte proliferation screening system and present a new drugable target with promise for the treatment of cardiac pathologies caused by cardiomyocyte loss.
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Affiliation(s)
- Ajit Magadum
- Department of Cardiac Development and Remodelling, Max-Planck-Institute for Heart and Lung Research, Parkstrasse 1, Bad Nauheim 61231, Germany
- Department of Cardiology, Icahn School of Medicine at Mount Sinai Hospital, One Gustave L. Levy Place, Box 1030, New York, NY 10029, USA
| | - Yishu Ding
- Department of Nutrition Sciences, University of Alabama at Birmingham, 1675 University Blvd, Birmingham, AL 35294-3360, USA
| | - Lan He
- Department of Nutrition Sciences, University of Alabama at Birmingham, 1675 University Blvd, Birmingham, AL 35294-3360, USA
| | - Teayoun Kim
- Department of Nutrition Sciences, University of Alabama at Birmingham, 1675 University Blvd, Birmingham, AL 35294-3360, USA
| | | | - Qinqiang Long
- Department of Nutrition Sciences, University of Alabama at Birmingham, 1675 University Blvd, Birmingham, AL 35294-3360, USA
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Ave, Wuhan, Hubei 430030, China
| | - Kevin Yang
- Department of Nutrition Sciences, University of Alabama at Birmingham, 1675 University Blvd, Birmingham, AL 35294-3360, USA
| | - Nadeera Wickramasinghe
- Department for Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, Box 1040, New York, NY 10029, USA
| | - Harsha V Renikunta
- Department of Cardiac Development and Remodelling, Max-Planck-Institute for Heart and Lung Research, Parkstrasse 1, Bad Nauheim 61231, Germany
| | - Nicole Dubois
- Department for Cell, Developmental and Regenerative Biology, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, Box 1040, New York, NY 10029, USA
| | - Gilbert Weidinger
- Institute of Biochemistry and Molecular Biology, Ulm University, Albert-Einstein-Allee 11, Ulm 89081, Germany
| | - Qinglin Yang
- Department of Nutrition Sciences, University of Alabama at Birmingham, 1675 University Blvd, Birmingham, AL 35294-3360, USA
- Division of Cardiology, Department of Internal Medicine, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, 1095 Jiefang Ave, Wuhan, Hubei 430030, China
| | - Felix B Engel
- Department of Cardiac Development and Remodelling, Max-Planck-Institute for Heart and Lung Research, Parkstrasse 1, Bad Nauheim 61231, Germany
- Department of Nephropathology, Experimental Renal and Cardiovascular Research, Institute of Pathology, Friedrich-Alexander-Universität Erlangen-Nürnberg, Schwabachanlage 12, Erlangen 91054, Germany
- Muscle Research Center Erlangen (MURCE)
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Bai YP, Xiao S, Tang YB, Tan Z, Tang H, Ren Z, Zeng H, Yang Z. Shear stress-mediated upregulation of GTP cyclohydrolase/tetrahydrobiopterin pathway ameliorates hypertension-related decline in reendothelialization capacity of endothelial progenitor cells. J Hypertens 2017; 35:784-797. [PMID: 28033126 DOI: 10.1097/hjh.0000000000001216] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
OBJECTIVES Guanosine triphosphate cyclohydrolase/tetrahydrobiopterin (GTPCH)/(BH4) pathway has been proved to regulate the function of endothelial progenitor cells (EPCs) in deoxycorticosterone acetate-salt hypertensive mice, indicating that GTPCH/BH4 pathway may be an important repair target for hypertension-related endothelial injury. Shear stress is an important nonpharmacologic strategy to modulate the function of EPCs. Here, we investigated the effects of laminar shear stress on the GTPCH/BH4 pathway and endothelial repair capacity of circulating EPCs in hypertension. METHOD Laminar shear stress was loaded on the human EPCs from hypertensive patients and normotensive patients. The in-vitro function, in-vivo reendothelialization capacity and GTPCH/BH4 pathway of human EPCs were evaluated. RESULTS Both in-vitro function and reendothelialization capacity of EPCs were lower in hypertensive patients than that in normotensive patients. The GTPCH/BH4 pathway of EPCs was downregulated in hypertensive patients. Shear stress increased in-vitro function and reendothelialization capacity of EPCs from hypertensive patients and normotensive patients. Furthermore, shear stress upregulated the expression of GTPCH I and levels of BH4, nitric oxide, and cGMP of EPCs, and reduced thrombospondin-1 expression. With treatment of GTPCH knockdown or nitroarginine methyl ester inhibition, shear stress-induced increased levels of BH4, nitric oxide and cGMP of EPCs was suppressed. When GTPCH/BH4 pathway of EPCs was blocked, the effects of shear stress on in-vitro function and reendothelialization capacity of EPCs were inhibited. CONCLUSION The study demonstrates for the first time that shear stress-induced upregulation of the GTPCH/BH4 pathway ameliorates hypertension-related decline in endothelial repair capacity of EPCs. These findings provide novel nonpharmacologic therapeutic approach for hypertension-related endothelial repair.
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Affiliation(s)
- Yong-Ping Bai
- aDepartment of Geriatric Medicine, Xiangya Hospital, Central South University, Changsha, Hunan bDepartment of Neurology, Sun Yat-Sen Memorial Hospital cDepartment of Pharmacology, Zhongshan School of Medicine dDepartment of Physiology, Zhongshan School of Medicine, Sun Yat-Sen University eSun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine fCenter for Reproductive Medicine, The Sixth Affiliated Hospital gDepartment of Hypertension & Vascular Disease, The First Affiliated Hospital, Sun Yat-Sen University, Guangzhou, Guangdong, People's Republic of China
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Zhang Z, Jiang M, Xie X, Yang H, Wang X, Xiao L, Wang N. Oleanolic acid ameliorates high glucose-induced endothelial dysfunction via PPARδ activation. Sci Rep 2017; 7:40237. [PMID: 28067284 PMCID: PMC5220361 DOI: 10.1038/srep40237] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Accepted: 12/02/2016] [Indexed: 02/07/2023] Open
Abstract
Oleanolic acid (3β-hydroxyolean-12-en-28-oic acid, OA) is a pentacyclic triterpenes widely distributed in food, medicinal plants and nutritional supplements. OA exhibits various pharmacological properties, such as hepatoprotective and anti-tumor effects. In this study, we analyzed the effect of OA on endothelial dysfunction induced by high glucose in human vascular endothelial cells (ECs). Western blotting showed that OA attenuated high glucose-reduced nitric production oxide (NO) as well as Akt-Ser473 and eNOS-Ser1177 phosphorylation in cultured human umbilical vein ECs (HUVECs). Next, luciferase reporter assay showed that OA activated peroxisome proliferators-activated receptor δ (PPARδ) activity. Quantitative reverse transcriptase PCR (qRT-PCR) demonstrated that OA increased the expressions of PPARδ target genes (PDK4, ADRP and ANGPTL4) in ECs. Meanwhile, the induced expressions of PDK4, ADRP and ANGPTL4 by OA were inhibited by GSK0660, a specific antagonist of PPARδ. In addition, inhibition of PPARδ abolished OA-induced the Akt-Ser473 and eNOS-Ser1177 phosphorylation, and NO production. Finally, by using Multi Myograph System, we showed that OA prevented high glucose-impaired vasodilation. This protective effect on vasodilation was inhibited in aortic rings pretreated with GSK0660. Collectively, we demonstrated that OA improved high glucose-impaired endothelial function via a PPARδ-mediated mechanism and through eNOS/Akt/NO pathway.
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Affiliation(s)
- Zihui Zhang
- Cardiovascular Research Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Manli Jiang
- Cardiovascular Research Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Xinya Xie
- Cardiovascular Research Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Haixia Yang
- Cardiovascular Research Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Xinfeng Wang
- Cardiovascular Research Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Lei Xiao
- Cardiovascular Research Center, Xi'an Jiaotong University, Xi'an, 710061, China
| | - Nanping Wang
- Cardiovascular Research Center, Xi'an Jiaotong University, Xi'an, 710061, China.,The Advanced Institute for Medical Sciences, Dalian Medical University, Dalian, 116044, China
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16
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He T, Santhanam AVR, Lu T, d'Uscio LV, Katusic ZS. Role of prostacyclin signaling in endothelial production of soluble amyloid precursor protein-α in cerebral microvessels. J Cereb Blood Flow Metab 2017; 37:106-122. [PMID: 26661245 PMCID: PMC5363732 DOI: 10.1177/0271678x15618977] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 10/20/2015] [Accepted: 10/30/2015] [Indexed: 12/20/2022]
Abstract
We tested hypothesis that activation of the prostacyclin (PGI2) receptor (IP receptor) signaling pathway in cerebral microvessels plays an important role in the metabolism of amyloid precursor protein (APP). In human brain microvascular endothelial cells activation of IP receptor with the stable analogue of PGI2, iloprost, stimulated expression of amyloid precursor protein and a disintegrin and metalloprotease 10 (ADAM10), resulting in an increased production of the neuroprotective and anticoagulant molecule, soluble APPα (sAPPα). Selective agonist of IP receptor, cicaprost, and adenylyl cyclase activator, forskolin, also enhanced expression of amyloid precursor protein and ADAM10. Notably, in cerebral microvessels of IP receptor knockout mice, protein levels of APP and ADAM10 were reduced. In addition, iloprost increased protein levels of peroxisome proliferator-activated receptor δ (PPARδ) in human brain microvascular endothelial cells. PPARδ-siRNA abolished iloprost-augmented protein expression of ADAM10. In contrast, GW501516 (a selective agonist of PPARδ) upregulated ADAM10 and increased production of sAPPα. Genetic deletion of endothelial PPARδ (ePPARδ-/-) in mice significantly reduced cerebral microvascular expression of ADAM10 and production of sAPPα. In vivo treatment with GW501516 increased sAPPα content in hippocampus of wild type mice but not in hippocampus of ePPARδ-/- mice. Our findings identified previously unrecognized role of IP-PPARδ signal transduction pathway in the production of sAPPα in cerebral microvasculature.
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Affiliation(s)
- Tongrong He
- Department of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Anantha Vijay R Santhanam
- Department of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Tong Lu
- Department of Internal Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Livius V d'Uscio
- Department of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Zvonimir S Katusic
- Department of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN, USA
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Santhanam AVR, d'Uscio LV, Katusic ZS. Characterization of cerebral microvasculature in transgenic mice with endothelium targeted over-expression of GTP-cyclohydrolase I. Brain Res 2015; 1625:198-205. [PMID: 26343845 PMCID: PMC4637228 DOI: 10.1016/j.brainres.2015.08.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Revised: 08/14/2015] [Accepted: 08/26/2015] [Indexed: 01/05/2023]
Abstract
Tetrahydrobiopterin (BH4) is a critical determinant of nitric oxide (NO) production by nitric oxide synthase (NOS) in the vascular endothelium and its biosynthesis is regulated by the enzymatic activity of GTP-cyclohydrolase I (GTPCH I). The present study was designed to determine the effects of endothelium-targeted overexpression of GTPCH I (eGCH-Tg) on murine cerebral vascular function. Endothelium targeted over-expression of GTPCH I was associated with a significant increase in levels of BH4, as well as its oxidized product, 7,8-dihydrobiopterin (7,8-BH2) in cerebral microvessels. Importantly, ratio of BH4 to 7,8-BH2, indicative of BH4 available for eNOS activation, was significantly increased in eGCH-Tg mice. However, expression of endothelial NOS, levels of nitrate/nitrite--indicative of NO production--remained unchanged between cerebral microvessels of wild-type and eGCH-Tg mice. Furthermore, increased BH4 biosynthesis neither affected production of superoxide anion nor expression of antioxidant proteins. Moreover, endothelium-specific GTPCH I overexpression did not alter intracellular levels of cGMP, reflective of NO signaling in cerebral microvessels. The obtained results suggest that, despite a significant increase in BH4 bioavailability, generation of endothelial NO in cerebral microvessels remained unchanged in eGCH-Tg mice. We conclude that under physiological conditions the levels of BH4 in the cerebral microvessels are optimal for activation of endothelial NOS and NO/cGMP signaling.
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Affiliation(s)
- Anantha Vijay R Santhanam
- Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Livius V d'Uscio
- Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Zvonimir S Katusic
- Departments of Anesthesiology and Molecular Pharmacology & Experimental Therapeutics, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.
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Santhanam AVR, d’Uscio LV, He T, Das P, Younkin SG, Katusic ZS. Uncoupling of endothelial nitric oxide synthase in cerebral vasculature of Tg2576 mice. J Neurochem 2015; 134:1129-38. [PMID: 26111938 PMCID: PMC5627976 DOI: 10.1111/jnc.13205] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 06/08/2015] [Accepted: 06/19/2015] [Indexed: 11/28/2022]
Abstract
In this study, we tested the hypothesis that reduced bioavailability of tetrahydrobiopterin (BH4) is a major mechanism responsible for pathogenesis of endothelial dysfunction in cerebral microvessels of transgenic mice expressing the Swedish double mutation of human amyloid precursor protein (APP) (Tg2576 mice). Endothelial nitric oxide synthase (eNOS) protein expression was significantly increased in cerebral vasculature of Tg2576 mice. In contrast, bioavailability of BH4 was significantly reduced (p < 0.05). Moreover, superoxide anion production was increased in cerebral microvessels of Tg2576 mice (p < 0.05). Incubation with NOS inhibitor, Nω-nitro-L-arginine methyl ester, decreased superoxide anion indicating that uncoupled eNOS is most likely the source of superoxide anion. Increasing BH4 bioavailability either exogenously by BH4 supplementation or endogenously by treatment with the selective peroxisome proliferator-activated receptor--delta activator GW501516 (2 mg/kg/day, 14 days) attenuated eNOS uncoupling and decreased superoxide anion production in cerebral microvessels of Tg2576 mice (p < 0.05). Treatment with GW501516 restored the biological activity of endothelial nitric oxide in cerebral microvessels of Tg2576 mice, as indicated by the increased nitrite/nitrate content and 3,5-cyclic guanosine monophosphate levels (p < 0.05). Our studies indicate that sub-optimal BH4 bioavailability in cerebral vasculature is an important contributor to oxidant stress and endothelial dysfunction in Tg2576 mouse model of Alzheimer's disease. Existing evidence suggests that Aβ peptides-induced up-regulation of expression and activity of NADPH oxidase causes increased production of superoxide anion (.O2(-)). .O2(-) can also be converted to hydrogen peroxide (H2O2) by enzymatic activity of superoxide dismutase (SOD) or spontaneous dismutation. Elevation of .O2(-) and H2O2 might cause oxidation of tetrahydrobiopterin (BH4) to dihydrobiopterin (BH2) and subsequent uncoupling of endothelial nitric oxide synthase (eNOS) (a) thus reducing levels of nitric oxide (NO) and 3',5'-cyclic guanosine monophosphate (cGMP). Supplementation of BH4 or activation of PPARδ prevents detrimental effects of eNOS uncoupling by restoring bioavailability of BH4 and scavenging of .O2(-), respectively (b). Activation of PPARδ also increases expression of catalase thereby inactivating H2O2. Generation of H2O2 by uncoupled eNOS in cerebral microvessels of Tg2576 mice is hypothetical.
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Affiliation(s)
- Anantha Vijay R. Santhanam
- Departments of Anesthesiology, and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN
| | - Livius V. d’Uscio
- Departments of Anesthesiology, and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN
| | - Tongrong He
- Departments of Anesthesiology, and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN
| | - Pritam Das
- Department of Neuroscience, Mayo Clinic, Jacksonville, FL
| | | | - Zvonimir S. Katusic
- Departments of Anesthesiology, and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN
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19
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Liu J, Wang L, Tian XY, Liu L, Wong WT, Zhang Y, Han QB, Ho HM, Wang N, Wong SL, Chen ZY, Yu J, Ng CF, Yao X, Huang Y. Unconjugated bilirubin mediates heme oxygenase-1-induced vascular benefits in diabetic mice. Diabetes 2015; 64:1564-75. [PMID: 25475440 DOI: 10.2337/db14-1391] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 11/26/2014] [Indexed: 12/20/2022]
Abstract
Heme oxygenase-1 (HO-1) exerts vasoprotective effects. Such benefit in diabetic vasculopathy, however, remains unclear. We hypothesize that bilirubin mediates HO-1-induced vascular benefits in diabetes. Diabetic db/db mice were treated with hemin (HO-1 inducer) for 2 weeks, and aortas were isolated for functional and molecular assays. Nitric oxide (NO) production was measured in cultured endothelial cells. Hemin treatment augmented endothelium-dependent relaxations (EDRs) and elevated Akt and endothelial NO synthase (eNOS) phosphorylation in db/db mouse aortas, which were reversed by the HO-1 inhibitor SnMP or HO-1 silencing virus. Hemin treatment increased serum bilirubin, and ex vivo bilirubin treatment improved relaxations in diabetic mouse aortas, which was reversed by the Akt inhibitor. Biliverdin reductase silencing virus attenuated the effect of hemin. Chronic bilirubin treatment improved EDRs in db/db mouse aortas. Hemin and bilirubin reversed high glucose-induced reductions in Akt and eNOS phosphorylation and NO production. The effect of hemin but not bilirubin was inhibited by biliverdin reductase silencing virus. Furthermore, bilirubin augmented EDRs in renal arteries from diabetic patients. In summary, HO-1-induced restoration of endothelial function in diabetic mice is most likely mediated by bilirubin, which preserves NO bioavailability through the Akt/eNOS/NO cascade, suggesting bilirubin as a potential therapeutic target for clinical intervention of diabetic vasculopathy.
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Affiliation(s)
- Jian Liu
- Institute of Vascular Medicine, Shenzhen Research Institute, and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Li Wang
- Institute of Vascular Medicine, Shenzhen Research Institute, and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Xiao Yu Tian
- Institute of Vascular Medicine, Shenzhen Research Institute, and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Limei Liu
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China
| | - Wing Tak Wong
- Department of Cardiovascular Sciences, Houston Methodist Research Institute, Houston, TX
| | - Yang Zhang
- Institute of Vascular Medicine, Shenzhen Research Institute, and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Quan-Bin Han
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China
| | - Hing-Man Ho
- School of Chinese Medicine, Hong Kong Baptist University, Hong Kong, China
| | - Nanping Wang
- Institute of Cardiovascular Science, Peking University, Beijing, China
| | - Siu Ling Wong
- Institute of Vascular Medicine, Shenzhen Research Institute, and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Zhen-Yu Chen
- School of Life Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Jun Yu
- Department of Medicine and Therapeutics, Chinese University of Hong Kong, Hong Kong, China
| | - Chi-Fai Ng
- Department of Surgery, Chinese University of Hong Kong, Hong Kong, China
| | - Xiaoqiang Yao
- Institute of Vascular Medicine, Shenzhen Research Institute, and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Yu Huang
- Institute of Vascular Medicine, Shenzhen Research Institute, and Li Ka Shing Institute of Health Sciences, Chinese University of Hong Kong, Hong Kong, China
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20
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Myers RB, Yoshioka J. Regulating PPARδ signaling as a potential therapeutic strategy for skeletal muscle disorders in heart failure. Am J Physiol Heart Circ Physiol 2015; 308:H967-9. [PMID: 25770240 DOI: 10.1152/ajpheart.00169.2015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Ronald B Myers
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Cambridge, Massachusetts
| | - Jun Yoshioka
- Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Cambridge, Massachusetts
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21
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Ryan BJ, Crabtree MJ, Channon KM, Wade-Martins R. Parkinson's disease in GTP cyclohydrolase 1 mutation carriers. Brain 2014; 138:e348. [PMID: 25398233 DOI: 10.1093/brain/awu308] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Brent J Ryan
- 1 Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Mark J Crabtree
- 1 Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Keith M Channon
- 1 Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK 1 Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
| | - Richard Wade-Martins
- 1 Oxford Parkinson's Disease Centre, Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford OX1 3QX, UK
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Abstract
Endothelial progenitor cells (EPCs) are primitive endothelial precursors which are known to functionally contribute to the pathogenesis of disease. To date a number of distinct subtypes of these cells have been described, with differing maturation status, cellular phenotype, and function. Although there is much debate on which subtype constitutes the true EPC population, all subtypes have endothelial characteristics and contribute to neovascularisation. Vasculogenesis, the process by which EPCs contribute to blood vessel formation, can be dysregulated in disease with overabundant vasculogenesis in the context of solid tumours, leading to tumour growth and metastasis, and conversely insufficient vasculogenesis can be present in an ischemic environment. Importantly, it is widely known that transcription factors tightly regulate cellular phenotype and function by controlling the expression of particular target genes and in turn regulating specific signalling pathways. This suggests that transcriptional regulators may be potential therapeutic targets to control EPC function. Herein, we discuss the observed EPC subtypes described in the literature and review recent studies describing the role of a number of transcriptional families in the regulation of EPC phenotype and function in normal and pathological conditions.
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Ehrenborg E, Skogsberg J. Peroxisome proliferator-activated receptor delta and cardiovascular disease. Atherosclerosis 2013; 231:95-106. [PMID: 24125418 DOI: 10.1016/j.atherosclerosis.2013.08.027] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/12/2013] [Revised: 08/16/2013] [Accepted: 08/27/2013] [Indexed: 12/20/2022]
Abstract
Recent reports have shown that peroxisome proliferator-activated receptor delta (PPARD) plays an important role in different vascular processes suggesting that PPARD is a significant modulator of cardiovascular disease. This review will focus on PPARD in relation to cardiovascular risk factors based on cell, animal and human data. Mouse studies suggest that Ppard is an important metabolic modulator that may have implications for cardiovascular disease (CVD). Specific human PPARD gene variants show no clear association with CVD but interactions between variants and lifestyle factors might influence disease risk. During recent years, development of specific and potent PPARD agonists has also made it possible to study the effects of PPARD activation in humans. PPARD agonists seem to exert beneficial effects on dyslipidemia and insulin-resistant syndromes but safety issues have been raised due to the role that PPARD plays in cell proliferation. Thus, large long term outcome as well as detailed safety and tolerability studies are needed to evaluate whether PPARD agonists could be used to treat CVD in humans.
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Affiliation(s)
- Ewa Ehrenborg
- Atherosclerosis Research Unit, Department of Medicine, Center for Molecular Medicine, Karolinska Institutet, Karolinska University Hospital, SE-171 76 Stockholm, Sweden.
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Barthelmes D, Irhimeh MR, Gillies MC, Karimipour M, Zhou M, Zhu L, Shen WY. Diabetes impairs mobilization of mouse bone marrow-derived Lin(-)/VEGF-R2(+) progenitor cells. Blood Cells Mol Dis 2013; 51:163-73. [PMID: 23714230 DOI: 10.1016/j.bcmd.2013.05.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2012] [Revised: 04/29/2013] [Accepted: 04/30/2013] [Indexed: 12/29/2022]
Abstract
Endothelial progenitor cells circulating in the peripheral blood (PB) contribute to vascular repair. This study aimed to evaluate the potential of a 'cocktail' consisting of erythropoietin, granulocyte colony-stimulating factor and tetrahydrobiopterin to mobilize hematopoietic lineage negative/vascular endothelial growth factor receptor 2 positive (Lin(-)/VEGF-R2(+)) cells from the bone marrow (BM) to PB in non-diabetic and diabetic mice. Diabetes was induced in mice by intraperitoneal injection of streptozotocin. Diabetic mice were studied after 16weeks of hyperglycemia. Half the mice in each group (non-diabetic and diabetic) received daily intraperitoneal injections of the cocktail for 6 consecutive days while the other half received vehicle buffer. Mobilization of Lin(-)/VEGF-R2(+) cells, which were expanded in MCP301 medium, was evaluated after isolating them from BM and PB and their phenotypic and morphological properties were studied. We found that 16weeks of diabetes affected neither the total number of BM mononucleated cells nor the number of Lin(-)/VEGF-R2(+) cells in BM compared with non-diabetic controls. In non-diabetic mice, cocktail treatment resulted in a significant decrease in BM Lin(-)/VEGF-R2(+) cells, paralleled by a significant increase of these cells in PB. Such changes in the number of Lin(-)/VEGF-R2(+) cells in BM and PB after the cocktail treatment were less marked in diabetic mice. In vitro studies of BM Lin(-)/VEGF-R2(+) cells from diabetic and non-diabetic mice did not reveal any differences in either phenotypes or colony forming potential. These findings indicate that diabetes impairs the mobilization of Lin(-)/VEGF-R2(+) cells from BM to PB. Impaired mobilization of BM Lin(-)/VEGF-R2(+) cells soon after the onset of diabetes may contribute to complications such as diabetic retinopathy.
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Affiliation(s)
- D Barthelmes
- Save Sight Institute, Sydney Hospital and Sydney Eye Hospital, The University of Sydney, Sydney, Australia
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Abstract
PURPOSE OF REVIEW The endothelial isoform of nitric oxide synthase (eNOS) is constitutively expressed but dynamically regulated by a number of factors. Building our knowledge of this regulation is necessary to understand and modulate the bioavailability of nitric oxide, central to the cardiovascular complications of diabetes and other diseases. This review will focus on the eNOS substrate (L-arginine), its cofactor (tetrahydrobiopterin), and mechanisms related to the uncoupling of eNOS activity. RECENT FINDINGS The global arginine bioavailability ratio has been proposed as a biomarker reflective of L-arginine availability, arginase activity, and citrulline cycling, as all of these processes impact eNOS activity. The failure of oral supplementation of tetrahydrobiopterin to recouple eNOS has emphasized the importance of the tetrahydrobiopterin to dihydrobiopterin ratio. Identification of transporters for biopterin species as well as signals that regulate endogenous arginine production have provided insight for alternative strategies to raise endothelial tetrahydrobiopterin levels while reducing dihydrobiopterin and alter eNOS activity. Finally, new information about redox regulation of eNOS itself may point to ways of controlling oxidative stress in the vasculature. SUMMARY Restoring proper eNOS activity is key to ameliorating or preventing cardiovascular complications of diabetes. Continued investigation is needed to uncover new means for maintaining endothelial nitric oxide bioavailability.
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Affiliation(s)
- Hai H Hoang
- Department of Systems Biology and Translational Medicine, Texas A&M Health Science Center, Temple, Texas 76504, USA
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Tian XY, Wong WT, Wang N, Lu Y, Cheang WS, Liu J, Liu L, Liu Y, Lee SST, Chen ZY, Cooke JP, Yao X, Huang Y. PPARδ activation protects endothelial function in diabetic mice. Diabetes 2012; 61:3285-93. [PMID: 22933110 PMCID: PMC3501853 DOI: 10.2337/db12-0117] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Recent evidence highlights the therapeutic potential of peroxisome proliferator-activated receptor-δ (PPARδ) agonists to increase insulin sensitivity in diabetes. However, the role of PPARδ in regulating vascular function is incompletely characterized. We investigate whether PPARδ activation improves endothelial function in diabetic and obese mice. PPARδ knockout (KO) and wild-type (WT) mice fed with high-fat diet and db/db mice were used as diabetic mouse models, compared with PPARδ KO and WT mice on normal diet and db/m(+) mice. Endothelium-dependent relaxation (EDR) was measured by wire myograph. Flow-mediated vasodilatation (FMD) was measured by pressure myograph. Nitric oxide (NO) production was examined in primary endothelial cells from mouse aortae. PPARδ agonist GW1516 restored EDRs in mouse aortae under high-glucose conditions or in db/db mouse aortae ex vivo. After oral treatment with GW1516, EDRs in aortae and FMDs in mesenteric resistance arteries were improved in obese mice in a PPARδ-specific manner. The effects of GW1516 on endothelial function were mediated through phosphatidylinositol 3-kinase (PI3K) and Akt with a subsequent increase of endothelial nitric oxide synthase (eNOS) activity and NO production. The current study demonstrates an endothelial-protective effect of PPARδ agonists in diabetic mice through PI3K/Akt/eNOS signaling, suggesting the therapeutic potential of PPARδ agonists for diabetic vasculopathy.
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Affiliation(s)
- Xiao Yu Tian
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Wing Tak Wong
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Nanping Wang
- Cardiovascular Research Center, Xi’an Jiaotong University, Xi’an, China
- Institute of Cardiovascular Science, Peking University Health Science Center, Beijing, China
- Corresponding author: Yu Huang, , or Nanping Wang,
| | - Ye Lu
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Wai San Cheang
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Jian Liu
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Limei Liu
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
- Department of Physiology and Pathophysiology, Peking University Health Science Center, Beijing, China
| | - Yahan Liu
- Institute of Cardiovascular Science, Peking University Health Science Center, Beijing, China
| | | | - Zhen Yu Chen
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong, China
| | - John P. Cooke
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University School of Medicine, Stanford, California
| | - Xiaoqiang Yao
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
| | - Yu Huang
- Institute of Vascular Medicine, Li Ka Shing Institute of Health Sciences, School of Biomedical Sciences, Chinese University of Hong Kong, Hong Kong, China
- Corresponding author: Yu Huang, , or Nanping Wang,
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d'Uscio LV, Das P, Santhanam AV, He T, Younkin SG, Katusic ZS. Activation of PPARδ prevents endothelial dysfunction induced by overexpression of amyloid-β precursor protein. Cardiovasc Res 2012; 96:504-12. [PMID: 22886847 PMCID: PMC3500044 DOI: 10.1093/cvr/cvs266] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2012] [Revised: 07/19/2012] [Accepted: 08/03/2012] [Indexed: 01/09/2023] Open
Abstract
AIMS Existing evidence suggests that amyloid-β precursor protein (APP) causes endothelial dysfunction and contributes to pathogenesis of atherosclerosis. In the present study, experiments were designed to: (1) determine the mechanisms underlying endothelial dysfunction and (2) define the effects of peroxisome proliferator-activated receptor delta (PPARδ) ligand on endothelial function in transgenic Tg2576 mice overexpressing mutated human APP. METHODS AND RESULTS Confocal microscopy and western blot analyses of wild-type mice aortas provided evidence that APP protein is mainly present in endothelial cells. Overexpression of APP significantly impaired endothelium-dependent relaxations to acetylcholine and phosphorylation of endothelial nitric oxide synthase at Ser(1177) in aortas. HPLC analysis revealed that tetrahydrobiopterin (BH(4)) levels were reduced in Tg2576 mice aortas. This was caused by increased oxidation of BH(4) and reduced expression and activity of GTP-cyclohydrolase I. Furthermore, gp91phox protein expression and superoxide anion production were increased in aortas of Tg2576 mice. This augmented superoxide formation was completely prevented by the NADPH oxidase inhibitor VAS2870. Expression of copper-/zinc-superoxide dismutase (Cu/ZnSOD) and extracellular SOD was downregulated. Treatment with PPARδ ligand GW501516 (2 mg/kg/day) for 14 days significantly increased BH(4) bioavailability and improved endothelium-dependent relaxations in Tg2576 mice aortas. GW501516 also normalized protein expression of gp91(phox) and SODs, thereby reducing production of superoxide anion in the aortas. CONCLUSION Our results suggest that in APP transgenic mice loss of nitric oxide and increased oxidative stress are the major causes of endothelial dysfunction. The vascular protective effects of GW501516 in Tg2576 mice appear to be critically dependent on prevention of superoxide anion production.
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Affiliation(s)
- Livius V. d'Uscio
- Department of Anesthesiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Pritam Das
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, FL, USA
| | - Anantha V.R. Santhanam
- Department of Anesthesiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Tongrong He
- Department of Anesthesiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
| | - Steven G. Younkin
- Department of Neuroscience, Mayo Clinic College of Medicine, Jacksonville, FL, USA
| | - Zvonimir S. Katusic
- Department of Anesthesiology, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
- Department of Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA
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28
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Santhanam AVR, d’Uscio LV, He T, Katusic ZS. PPARδ agonist GW501516 prevents uncoupling of endothelial nitric oxide synthase in cerebral microvessels of hph-1 mice. Brain Res 2012; 1483:89-95. [PMID: 22982594 PMCID: PMC3474319 DOI: 10.1016/j.brainres.2012.09.012] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2012] [Revised: 08/24/2012] [Accepted: 09/07/2012] [Indexed: 01/06/2023]
Abstract
Peroxisome proliferator-activated receptor delta (PPARδ) is ubiquitously expressed in the vasculature, including cerebral circulation. The role of PPARδ in metabolism of tetrahydrobiopterin (BH₄) has not been studied in the cerebral microvasculature. In the present study, the effects of PPARδ agonist GW501516 on uncoupling of endothelial nitric oxide synthase (eNOS) were determined in cerebral microvessels of BH₄-deficient hph-1 mice. Wild-type (B6CBA) and hph-1 mice were orally gavaged with a selective PPARδ activator, GW501516 (2 mg/kg/day) for 14 days, and thereafter, cerebral microvessels were isolated and studied. Treatment of hph-1 mice with GW501516 significantly reduced oxidation of BH₄ and increased the ratio of BH₄ to 7,8-BH₂ (P<0.05, n=6-9). Attenuation of L-NAME-inhibitable superoxide anion levels by GW501516 demonstrated that activation of PPARδ might prevent uncoupling of endothelial nitric oxide synthase (eNOS, P<0.05, n=6-9). Western blotting studies demonstrated that GW501516 selectively increased the endothelial expressions of CuZn superoxide dismutase (P<0.05, n=6-9) and catalase (P<0.05, n=6-8). PPARδ activation increased the total nitrite and nitrate (NO₂+NO₃) content in cerebral microvessels (P<0.05, n=6). Obtained results suggest that in vivo activation of PPARδ prevents eNOS uncoupling, restores bioavailability of NO and may help preserve endothelial function in the BH₄-deficient cerebral circulation.
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Affiliation(s)
- Anantha Vijay R. Santhanam
- Departments of Anesthesiology, and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Livius V. d’Uscio
- Departments of Anesthesiology, and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Tongrong He
- Departments of Anesthesiology, and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905
| | - Zvonimir S. Katusic
- Departments of Anesthesiology, and Molecular Pharmacology and Experimental Therapeutics, Mayo Clinic College of Medicine, Rochester, MN 55905
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Altieri P, Spallarossa P, Barisione C, Garibaldi S, Garuti A, Fabbi P, Ghigliotti G, Brunelli C. Inhibition of doxorubicin-induced senescence by PPARδ activation agonists in cardiac muscle cells: cooperation between PPARδ and Bcl6. PLoS One 2012; 7:e46126. [PMID: 23049957 PMCID: PMC3458009 DOI: 10.1371/journal.pone.0046126] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2012] [Accepted: 08/28/2012] [Indexed: 01/29/2023] Open
Abstract
Senescence and apoptosis are two distinct cellular programs that are activated in response to a variety of stresses. Low or high doses of the same stressor, i.e., the anticancer drug doxorubicin, may either induce apoptosis or senescence, respectively, in cardiac muscle cells. We have demonstrated that PPARδ, a ligand-activated transcriptional factor that controls lipid metabolism, insulin sensitivity and inflammation, is also involved in the doxorubicin-induced senescence program. This occurs through its interference with the transcriptional repressor protein B cell lymphoma-6 (Bcl6). Low doses of doxorubicin increase the expression of PPARδ that sequesters Bcl6, thus preventing it from exerting its anti-senescent effects. We also found that L-165041, a specific PPARδ activator, is highly effective in protecting cardiomyocytes from doxorubicin-induced senescence through a Bcl6 related mechanism. In fact, L-165041 increases Bcl6 expression via p38, JNK and Akt activation, and at the same time it induces the release of Bcl6 from PPARδ, thereby enabling Bcl6 to bind to its target genes. L-165041 also prevented apoptosis induced by higher doses of doxorubicin. However, while experiments performed with siRNA analysis techniques very clearly showed the weight of Bcl6 in the cellular senescence program, no role was found for Bcl6 in the anti-apoptotic effects of L-165041, thus confirming that senescence and apoptosis are two very distinct stress response cellular programs. This study increases our understanding of the molecular mechanism of anthracycline cardiotoxicity and suggests a potential role for PPARδ agonists as cardioprotective agents.
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Affiliation(s)
- Paola Altieri
- Research Centre of Cardiovascular Biology, University of Genova, Genova, Italy.
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Lu T, Chai Q, Yu L, d'Uscio LV, Katusic ZS, He T, Lee HC. Reactive oxygen species signaling facilitates FOXO-3a/FBXO-dependent vascular BK channel β1 subunit degradation in diabetic mice. Diabetes 2012; 61:1860-8. [PMID: 22586590 PMCID: PMC3379647 DOI: 10.2337/db11-1658] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Activity of the vascular large conductance Ca(2+)-activated K(+) (BK) channel is tightly regulated by its accessory β(1) subunit (BK-β(1)). Downregulation of BK-β(1) expression in diabetic vessels is associated with upregulation of the forkhead box O subfamily transcription factor-3a (FOXO-3a)-dependent F-box-only protein (FBXO) expression. However, the upstream signaling regulating this process is unclear. Overproduction of reactive oxygen species (ROS) is a common finding in diabetic vasculopathy. We hypothesized that ROS signaling cascade facilitates the FOXO-3a/FBXO-mediated BK-β(1) degradation and leads to diabetic BK channel dysfunction. Using cellular biology, patch clamp, and videomicroscopy techniques, we found that reduced BK-β(1) expression in streptozotocin (STZ)-induced diabetic mouse arteries and in human coronary smooth muscle cells (SMCs) cultured with high glucose was attributable to an increase in protein kinase C (PKC)-β and NADPH oxidase expressions and accompanied by attenuation of Akt phosphorylation and augmentation of atrogin-1 expression. Treatment with ruboxistaurin (a PKCβ inhibitor) or with GW501516 (a peroxisome proliferator-activated receptor δ activator) reduced atrogin-1 expression and restored BK channel-mediated coronary vasodilation in diabetic mice. Our results suggested that oxidative stress inhibited Akt signaling and facilitated the FOXO-3a/FBXO-dependent BK-β(1) degradation in diabetic vessels. Suppression of the FOXO-3a/FBXO pathway prevented vascular BK-β(1) degradation and protected coronary function in diabetes.
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Affiliation(s)
- Tong Lu
- Department of Internal Medicine, Mayo Clinic, Rochester, Minnesota, USA.
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Katusic ZS, Santhanam AV, He T. Vascular effects of prostacyclin: does activation of PPARδ play a role? Trends Pharmacol Sci 2012; 33:559-64. [PMID: 22727878 DOI: 10.1016/j.tips.2012.05.005] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 05/11/2012] [Accepted: 05/22/2012] [Indexed: 02/06/2023]
Abstract
Prostacyclin (PGI(2)) is a potent vasodilator that exerts multiple vasoprotective effects in the cardiovascular system. The effects of PGI(2) are mediated by activation of the cell membrane G-protein-coupled PGI(2) receptor (IP receptor). More recently, however, it has been suggested that PGI(2) might also serve as an endogenous ligand and activator of nuclear peroxisome proliferator-activated receptorδ (PPARδ). Consistent with this concept, studies designed to define pharmacological properties of stable PGI(2) analogs revealed that beneficial effects of these compounds appear to be mediated, in part, by activation of PPARδ. This review discusses emerging evidence regarding the contribution of PPARδ activation to vasoprotective and regenerative functions of PGI(2) and stable analogs of PGI(2).
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Affiliation(s)
- Zvonimir S Katusic
- Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN, USA.
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Meininger CJ, Wu G. Tetrahydrobiopterin: important endothelial mediator independent of endothelial nitric oxide synthase. Hypertension 2011; 58:145-7. [PMID: 21709208 PMCID: PMC3160747 DOI: 10.1161/hypertensionaha.111.174003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Cynthia J. Meininger
- Department of Systems Biology and Translational Medicine, Texas A&M Health Science Center, Temple, TX
| | - Guoyao Wu
- Department of Systems Biology and Translational Medicine, Texas A&M Health Science Center, Temple, TX
- Department of Animal Science, Texas A&M University, College Station, TX
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