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Crosswhite P, Sun Z. TNFα Induces DNA and Histone Hypomethylation and Pulmonary Artery Smooth Muscle Cell Proliferation Partly via Excessive Superoxide Formation. Antioxidants (Basel) 2024; 13:677. [PMID: 38929115 PMCID: PMC11200563 DOI: 10.3390/antiox13060677] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/17/2024] [Accepted: 05/27/2024] [Indexed: 06/28/2024] Open
Abstract
Objective: The level of tumor necrosis factor-α (TNF-α) is upregulated during the development of pulmonary vascular remodeling and pulmonary hypertension. A hallmark of pulmonary arterial (PA) remodeling is the excessive proliferation of PA smooth muscle cells (PASMCs). The purpose of this study is to investigate whether TNF-α induces PASMC proliferation and explore the potential mechanisms. Methods: PASMCs were isolated from 8-week-old male Sprague-Dawley rats and treated with 0, 20, or 200 ng/mL TNF-α for 24 or 48 h. After treatment, cell number, superoxide production, histone acetylation, DNA methylation, and histone methylation were assessed. Results: TNF-α treatment increased NADPH oxidase activity, superoxide production, and cell numbers compared to untreated controls. TNF-α-induced PASMC proliferation was rescued by a superoxide dismutase mimetic tempol. TNF-α treatment did not affect histone acetylation at either dose but did significantly decrease DNA methylation. DNA methyltransferase 1 activity was unchanged by TNF-α treatment. Further investigation using QRT-RT-PCR revealed that GADD45-α, a potential mediator of DNA demethylation, was increased after TNF-α treatment. RNAi inhibition of GADD45-α alone increased DNA methylation. TNF-α impaired the epigenetic mechanism leading to DNA hypomethylation, which can be abolished by a superoxide scavenger tempol. TNF-α treatment also decreased H3-K4 methylation. TNF-α-induced PASMC proliferation may involve the H3-K4 demethylase enzyme, lysine-specific demethylase 1 (LSD1). Conclusions: TNF-α-induced PASMC proliferation may be partly associated with excessive superoxide formation and histone and DNA methylation.
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Affiliation(s)
- Patrick Crosswhite
- Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Department of Human Physiology, Gonzaga University, Spokane, WA 99205, USA
| | - Zhongjie Sun
- Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Department of Physiology, College of Medicine, University of Tennessee Health Sciences Center, Memphis, TN 38163, USA
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2
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Fan J, Wang S, Chen K, Sun Z. Aging impairs arterial compliance via Klotho-mediated downregulation of B-cell population and IgG levels. Cell Mol Life Sci 2022; 79:494. [PMID: 36001158 PMCID: PMC10082671 DOI: 10.1007/s00018-022-04512-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2022] [Revised: 07/31/2022] [Accepted: 08/01/2022] [Indexed: 11/27/2022]
Abstract
OBJECTIVE Aging is associated with compromised immune function and arterial remodeling and stiffness. The purpose of this study is to investigate whether in vivo AAV-based delivery of secreted Klotho (SKL) gene (AAV-SKL) improves aging- and senescence-associated immune dysfunction and arterial stiffness. METHODS AND RESULTS Senescence-accelerated mice prone strain 1 (SAMP1, 10 months) and old mice (20 months) were used. Serum SKL levels, B-cell population and serum IgG levels were markedly decreased in SAMP1 and old mice. Rescue of downregulation of serum SKL levels by in vivo AAV2-based delivery of SKL gene (AAV-SKL) increased B-cell population and serum IgG levels and attenuated arterial stiffness in SAMP1 and old mice. Thus, Klotho deficiency may play a role in senescence- and aging-associated humoral immune dysfunction and arterial stiffness. Vascular infiltration of inflammatory cells and expression of TGFβ1, collagen 1, scleraxis, MMP-2 and MMP-9 were increased while the elastin level was decreased in aortas of SAMP1 and old mice which can be rescued by AAV-SKL. Interestingly, treatment with IgG effectively rescued arterial inflammation and remodeling and attenuated arterial stiffness and hypertension in aging mice. In cultured B-lymphoblast cells, we further showed that SKL regulates B-cell proliferation and maturation partly via the NFkB pathway. CONCLUSION Aging-associated arterial stiffening may be largely attributed to downregulation of B-cell population and serum IgG levels. AAV-SKL attenuates arterial stiffness in aging mice partly via restoring B-cell population and serum IgG levels which attenuates aging-associated vascular inflammation and arterial remodeling.
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Affiliation(s)
- Jun Fan
- Department of Physiology, College of Medicine, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Shirley Wang
- Department of Physiology, College of Medicine, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
| | - Kai Chen
- Department of Physiology, College of Medicine, University of Oklahoma Health Science Center, Oklahoma City, OK, USA
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, A302 Coleman Building, 956 Court Avenue, Memphis, TN, 38163, USA
| | - Zhongjie Sun
- Department of Physiology, College of Medicine, University of Oklahoma Health Science Center, Oklahoma City, OK, USA.
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, A302 Coleman Building, 956 Court Avenue, Memphis, TN, 38163, USA.
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3
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Chen K, Sun Z. Estrogen inhibits renal Na-Pi Co-transporters and improves klotho deficiency-induced acute heart failure. Redox Biol 2021; 47:102173. [PMID: 34678656 PMCID: PMC8577443 DOI: 10.1016/j.redox.2021.102173] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Revised: 10/17/2021] [Accepted: 10/17/2021] [Indexed: 01/06/2023] Open
Abstract
Objective and hypothesis Klotho is an aging-suppressor gene. Mutation of Klotho gene causes hyperphosphatemia and acute heart failure. However, the relationship of hyperphosphatemia and acute heart failure is unclear. We hypothesize that hyperphosphatemia mediates Klotho deficiency-induced acute heart failure and further that therapeutic reduction of hyperphosphatemia prevents acute heart failure in Klotho mutant (KL(−/−)) mice. Methods and results A significant elevation of serum phosphorus levels and a large reduction of heart function were found in KL(−/−) mice by six weeks of age. Normalization of serum phosphorus levels by low phosphate diet (LPD) rescued Klotho deficiency-induced heart failure and extended lifespan in male mice. Klotho deficiency impaired cardiac mitochondrial respiratory enzyme function and increased superoxide production, oxidative stress, and cardiac cell apoptosis in male KL(−/−) mice which can be eliminated by LPD. LPD, however, did not rescue hyperphosphatemia or heart failure in female KL(−/−) mice. LPD did not affect estrogen depletion in female KL(−/−) mice. Normalization of serum estrogen levels by treatment with 17β-estradiol prevented hyperphosphatemia and heart failure in female KL(−/−) mice. Mechanistically, treatment with 17β-estradiol rescued hyperphosphatemia via inhibiting renal Na-Pi co-transporter expression. Normalization of serum phosphorus levels by treatment with 17β-estradiol also abolished cardiac mitochondrial respiratory enzyme dysfunction, ROS overproduction, oxidative stress and cardiac cell apoptosis in female KL(−/−) mice. Conclusion Klotho deficiency causes acute heart failure via hyperphosphatemia in male mice which can be prevented by LPD. 17β-estradiol prevents Klotho deficiency-induced hyperphosphatemia and heart failure by eliminating upregulation of renal Na-Pi co-transporter expression in female mice.
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Affiliation(s)
- Kai Chen
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Zhongjie Sun
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, TN, 38163, USA.
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4
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Bigalke JA, Gao H, Chen QH, Shan Z. Activation of Orexin 1 Receptors in the Paraventricular Nucleus Contributes to the Development of Deoxycorticosterone Acetate-Salt Hypertension Through Regulation of Vasopressin. Front Physiol 2021; 12:641331. [PMID: 33633591 PMCID: PMC7902066 DOI: 10.3389/fphys.2021.641331] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2020] [Accepted: 01/13/2021] [Indexed: 12/13/2022] Open
Abstract
Salt-sensitivity is a major factor in the development of hypertension. The brain orexin system has been observed to play a role in numerous hypertensive animal models. However, orexin’s role in the pathology of salt-sensitive hypertension (SSH) remains to be adequately explored. We assessed the impact of orexin hyperactivity in the pathogenesis of the deoxycorticosterone acetate (DOCA) – salt rat model, specifically through modulation of Arginine Vasopressin (AVP). Adult male rats were separated into three groups: vehicle control, DOCA-salt, and DOCA-salt+OX1R-shRNA. DOCA-salt rats received subcutaneous implantation of a 21-day release, 75 mg DOCA pellet in addition to saline drinking water (1% NaCl and 0.2% KCl). DOCA-salt+OX1R-shRNA rats received bilateral microinjection of AAV2-OX1R-shRNA into the paraventricular nucleus (PVN) to knockdown function of the Orexin 1-Receptor (OX1R) within that area. Following 2-week to allow full transgene expression, a DOCA pellet was administered in addition to saline drinking solution. Vehicle controls received sham DOCA implantation but were given normal water. During the 3-week DOCA-salt or sham treatment period, mean arterial pressure (MAP) and heart rate (HR) were monitored utilizing tail-cuff plethysmography. Following the 3-week period, rat brains were collected for either PCR mRNA analysis, as well as immunostaining. Plasma samples were collected and subjected to ELISA analysis. In line with our hypothesis, OX1R expression was elevated in the PVN of DOCA-salt treated rats when compared to controls. Furthermore, following chronic knockdown of OX1R, the hypertension development normally induced by DOCA-salt treatment was significantly diminished in the DOCA-salt+OX1R-shRNA group. A concurrent reduction in PVN OX1R and AVP mRNA was observed in concert with the reduced blood pressure following AAV2-OX1R-shRNA treatment. Similarly, plasma AVP concentrations appeared to be reduced in the DOCA-salt+OX1R-shRNA group when compared to DOCA-salt rats. These results indicate that orexin signaling, specifically through the OX1R in the PVN are critical for the onset and maintenance of hypertension in the DOCA-salt model. This relationship is mediated, at least in part, through orexin activation of AVP producing neurons, and the subsequent release of AVP into the periphery. Our results outline a promising mechanism underlying the development of SSH through interactions with the brain orexin system.
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Affiliation(s)
- Jeremy A Bigalke
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Department of Psychology, Montana State University, Bozeman, MT, United States
| | - Huanjia Gao
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,The Second Clinical College of Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Qing-Hui Chen
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Health Research Institute, Michigan Technological University, Houghton, MI, United States
| | - Zhiying Shan
- Department of Kinesiology and Integrative Physiology, Michigan Technological University, Houghton, MI, United States.,Health Research Institute, Michigan Technological University, Houghton, MI, United States
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5
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Gao D, Wang S, Lin Y, Sun Z. In vivo AAV delivery of glutathione reductase gene attenuates anti-aging gene klotho deficiency-induced kidney damage. Redox Biol 2020; 37:101692. [PMID: 32863229 PMCID: PMC7476318 DOI: 10.1016/j.redox.2020.101692] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 07/27/2020] [Accepted: 08/17/2020] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE Klotho is an aging-suppressor gene which leads to accelerated aging when disrupted. This study was designed to investigate whether glutathione reductase (GR), a critical intracellular antioxidant enzyme, is involved in the pathogenesis of kidney damages associated with accelerated aging in Klotho-haplodeficient (KL+/-) mice. METHODS AND RESULTS Klotho-haplodeficient (KL+/-) mice and WT mice were used. We found that Klotho haplodeficiency impaired kidney function as evidenced by significant increases in plasma urea and creatinine and a decrease in urinary creatinine in KL+/- mice. The expression and activity of GR was decreased significantly in renal tubular epithelial cells of KL+/- mice, suggesting that Klotho deficiency downregulated GR. We constructed adeno-associated virus 2 (AAV2) carrying GR full-length cDNA (AAV-GR). Interestingly, in vivo AAV-GR delivery significantly improved Klotho deficiency-induced renal functional impairment and structural remodeling. Furthermore, in vivo expression of GR rescued the downregulation of the reduced glutathione/oxidized glutathione (GSH/GSSG) ratio, which subsequently diminished oxidative damages in kidneys, as evidenced by significant decreases in renal 4-HNE expression and urinary 8-isoprostane levels in KL mice. CONCLUSION This study provides the first evidence that Klotho deficiency-induced kidney damage may be partly attributed to downregulation of GR expression. In vivo delivery of AAV-GR may be a promising therapeutic approach for aging-related kidney damage.
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Affiliation(s)
- Diansa Gao
- Department of Cardiology, The First Affiliated Hospital, Chongqing Medical University, Chongqing, China
| | - Shirley Wang
- Department of Physiology, College of Medicine, University of Tennessee Health Sciences Center, Memphis, TN, 38163, USA
| | - Yi Lin
- Department of Physiology, College of Medicine, University of Tennessee Health Sciences Center, Memphis, TN, 38163, USA
| | - Zhongjie Sun
- Department of Physiology, College of Medicine, University of Tennessee Health Sciences Center, Memphis, TN, 38163, USA.
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6
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Feng R, Ullah M, Chen K, Ali Q, Lin Y, Sun Z. Stem cell-derived extracellular vesicles mitigate ageing-associated arterial stiffness and hypertension. J Extracell Vesicles 2020; 9:1783869. [PMID: 32939234 PMCID: PMC7480600 DOI: 10.1080/20013078.2020.1783869] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 02/01/2020] [Accepted: 04/24/2020] [Indexed: 12/19/2022] Open
Abstract
The prevalence of arterial stiffness and hypertension increases with age. This study investigates the effect of induced pluripotent mesenchymal stem cell-derived extracellular vesicles (EVs) on ageing-associated arterial stiffness and hypertension. EVs were collected and purified from induced pluripotent stem cell-derived mesenchymal stem cells (iPS-MSCs). Young and old male C57BL/6 mice were used. Mice in the EVs group were injected via tail vein once a week for four weeks (18 x 106 EVs/mouse/injection). Blood pressure (BP) was measured using the tail-cuff method and validated by direct cannulation. Pulse wave velocity (PWV) was measured using a Doppler workstation. PWV and BP were increased significantly in the old mice, indicating arterial stiffness and hypertension. Intravenous administration of EVs significantly attenuated ageing-related arterial stiffness and hypertension, while enhancing endothelium-dependent vascular relaxation and arterial compliance in the old EVs mice. Elastin degradation and collagen I deposition (fibrosis) were increased in aortas of the old mice, but EVs substantially improved ageing-associated structural remodelling. Mechanistically, EVs abolished downregulation of sirtuin type 1 (SIRT1), and endothelial nitric oxide synthase (eNOS) protein expression in aortas of the older mice. In cultured human aortic endothelial cells, EVs promoted the expression of SIRT1, AMP-activated protein kinase alpha (AMPKα), and eNOS. In conclusion, iPS-MSC-derived EVs attenuated ageing-associated vascular endothelial dysfunction, arterial stiffness, and hypertension, likely via activation of the SIRT1-AMPKα-eNOS pathway and inhibition of MMPs and elastase. Thus, EVs mitigate arterial ageing. This finding also sheds light into the therapeutic potential of EVs for ageing-related vascular diseases. ABBREVIATIONS EV: Extracellular vesicles; iPS: induced pluripotent stem cell; MSC: mesenchymal stem cell; AMPKα: AMP activated protein kinase α; eNOS: endothelial nitric oxide synthase; Sirt1: sirtuin 1; JNC7: Seventh Report of the Joint National Committee; CVD: cardiovascular disease; PWV: pulse wave velocity; BP: blood pressure; SNP: sodium nitroprusside.
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Affiliation(s)
- Rui Feng
- Department of Cardiology, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Mujib Ullah
- Department of Physiology, College of Medicine, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Kai Chen
- Department of Physiology, College of Medicine, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Quaisar Ali
- Department of Physiology, College of Medicine, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Yi Lin
- Department of Physiology, College of Medicine, University of Tennessee Health Sciences Center, Memphis, TN, USA
| | - Zhongjie Sun
- Department of Physiology, College of Medicine, University of Tennessee Health Sciences Center, Memphis, TN, USA
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7
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Course MM, Gudsnuk K, Desai N, Chamberlain JR, Valdmanis PN. Endogenous MicroRNA Competition as a Mechanism of shRNA-Induced Cardiotoxicity. MOLECULAR THERAPY. NUCLEIC ACIDS 2020; 19:572-580. [PMID: 31927330 PMCID: PMC6957822 DOI: 10.1016/j.omtn.2019.12.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Revised: 12/12/2019] [Accepted: 12/12/2019] [Indexed: 11/29/2022]
Abstract
Gene knockdown using short hairpin RNAs (shRNAs) is a promising strategy for targeting dominant mutations; however, delivering too much shRNA can disrupt the processing of endogenous microRNAs (miRNAs) and lead to toxicity. Here, we sought to understand the effect that excessive shRNAs have on muscle miRNAs by treating mice with recombinant adeno-associated viral vectors (rAAVs) that produce shRNAs with 19-nt or 21-nt stem sequences. Small RNA sequencing of their muscle and liver tissues revealed that shRNA expression was highest in the heart, where mice experienced substantial cardiomyopathy when shRNAs accumulated to 51.2% ± 13.7% of total small RNAs. With the same treatment, shRNAs in other muscle tissues reached only 12.1% ± 5.0% of total small RNAs. Regardless of treatment, the predominant heart miRNAs remained relatively stable across samples. Instead, the lower-expressed miR-451, one of the few miRNAs processed independently of Dicer, changed in relation to shRNA level and toxicity. Our data suggest that a protective mechanism exists in cardiac tissue for maintaining the levels of most miRNAs in response to shRNA delivery, in contrast with what has been shown in the liver. Quantifying miRNA profiles after excessive shRNA delivery illuminates the host response to rAAV-shRNA, allowing for safer and more robust therapeutic gene knockdown.
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Affiliation(s)
- Meredith M Course
- Division of Medical Genetics, University of Washington School of Medicine, Seattle, WA, USA
| | - Kathryn Gudsnuk
- Division of Medical Genetics, University of Washington School of Medicine, Seattle, WA, USA
| | - Nitin Desai
- Division of Medical Genetics, University of Washington School of Medicine, Seattle, WA, USA
| | - Joel R Chamberlain
- Division of Medical Genetics, University of Washington School of Medicine, Seattle, WA, USA
| | - Paul N Valdmanis
- Division of Medical Genetics, University of Washington School of Medicine, Seattle, WA, USA.
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8
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Li RM, Chen SQ, Zeng NX, Zheng SH, Guan L, Liu HM, Zhou LQ, Xu JW. Browning of Abdominal Aorta Perivascular Adipose Tissue Inhibits Adipose Tissue Inflammation. Metab Syndr Relat Disord 2017; 15:450-457. [DOI: 10.1089/met.2017.0074] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Affiliation(s)
- Run-Mei Li
- Department of Physiology, Basic Medical College, Guangzhou University of Chinese Medicine, University Town, Guangzhou, China
- Department of National Experimental Teaching Demonstration Center of Chinese Medicine, School of Chinese Pharmaceutical Science, Guangzhou University of Chinese Medicine, University Town, Guangzhou, China
| | - Sui-Qing Chen
- Department of Physiology, Basic Medical College, Guangzhou University of Chinese Medicine, University Town, Guangzhou, China
| | - Ning-Xi Zeng
- Department of Physiology, Basic Medical College, Guangzhou University of Chinese Medicine, University Town, Guangzhou, China
| | - Shu-Hui Zheng
- Research Center of Translational Medicine, The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Li Guan
- Department of Physiology, Basic Medical College, Guangzhou University of Chinese Medicine, University Town, Guangzhou, China
| | - Hai-Mei Liu
- Department of Physiology, Basic Medical College, Guangzhou University of Chinese Medicine, University Town, Guangzhou, China
| | - Le-Quan Zhou
- Department of Physiology, Basic Medical College, Guangzhou University of Chinese Medicine, University Town, Guangzhou, China
| | - Jin-Wen Xu
- Department of Physiology, Basic Medical College, Guangzhou University of Chinese Medicine, University Town, Guangzhou, China
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9
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Li M, Tjen-A-Looi SC, Guo ZL, Longhurst JC. Repetitive Electroacupuncture Attenuates Cold-Induced Hypertension through Enkephalin in the Rostral Ventral Lateral Medulla. Sci Rep 2016; 6:35791. [PMID: 27775047 PMCID: PMC5075898 DOI: 10.1038/srep35791] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2016] [Accepted: 10/04/2016] [Indexed: 02/07/2023] Open
Abstract
Acupuncture lowers blood pressure (BP) in hypertension, but mechanisms underlying its action are unclear. To simulate clinical studies, we performed electroacupuncture (EA) in unanesthetized rats with cold-induced hypertension (CIH) induced by six weeks of cold exposure (6 °C). EA (0.1 - 0.4 mA, 2 Hz) was applied at ST36-37 acupoints overlying the deep peroneal nerve for 30 min twice weekly for five weeks while sham-EA was conducted with the same procedures as EA except for no electrical stimulation. Elevated BP was reduced after six sessions of EA treatment and remained low 72 hrs after EA in 18 CIH rats, but not in sham-EA (n = 12) and untreated (n = 6) CIH ones. The mRNA level of preproenkephalin in the rostral ventrolateral medulla (rVLM) 72 hr after EA was increased (n = 9), compared to the sham-EA (n = 6), untreated CIH rats (n = 6) and normotensive control animals (n = 6). Microinjection of ICI 174,864, a δ-opioid receptor antagonist, into the rVLM of EA-treated CIH rats partially reversed EA's effect on elevated BP (n = 4). Stimulation of rVLM of CIH rats treated with sham-EA using a δ-opioid agonist, DADLE, decreased BP (n = 6). These data suggest that increased enkephalin in the rVLM induced by repetitive EA contributes to BP lowering action of EA.
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Affiliation(s)
- Min Li
- Department of Medicine and Susan Samueli Center of Integrative Medicine, School of Medicine, University of California, Irvine, CA 92697-4075, USA
| | - Stephanie C. Tjen-A-Looi
- Department of Medicine and Susan Samueli Center of Integrative Medicine, School of Medicine, University of California, Irvine, CA 92697-4075, USA
| | - Zhi-Ling Guo
- Department of Medicine and Susan Samueli Center of Integrative Medicine, School of Medicine, University of California, Irvine, CA 92697-4075, USA
| | - John C. Longhurst
- Department of Medicine and Susan Samueli Center of Integrative Medicine, School of Medicine, University of California, Irvine, CA 92697-4075, USA
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10
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Chen PGF, Sun Z. AAV Delivery of Endothelin-1 shRNA Attenuates Cold-Induced Hypertension. Hum Gene Ther 2016; 28:190-199. [PMID: 27736201 DOI: 10.1089/hum.2016.047] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Cold temperatures are associated with increased prevalence of hypertension. Cold exposure increases endothelin-1 (ET1) production. The purpose of this study is to determine whether upregulation of ET1 contributes to cold-induced hypertension (CIH). In vivo RNAi silencing of the ET1 gene was achieved by adeno-associated virus 2 (AAV2) delivery of ET1 short-hairpin small interfering RNA (ET1-shRNA). Four groups of male rats were used. Three groups were given AAV.ET1-shRNA, AAV.SC-shRNA (scrambled shRNA), and phosphate-buffered saline (PBS), respectively, before exposure to a moderately cold environment (6.7 ± 2°C), while the last group was given PBS and kept at room temperature (warm, 24 ± 2°C) and served as a control. We found that systolic blood pressure of the PBS-treated and SC-shRNA-treated groups increased significantly within 2 weeks of exposure to cold, reached a peak level (145 ± 4.8 mmHg) by 6 weeks, and remained elevated thereafter. By contrast, blood pressure of the ET1-shRNA-treated group did not increase, suggesting that silencing of ET1 prevented the development of CIH. Animals were euthanized after 10 weeks of exposure to cold. Cold exposure significantly increased the left ventricle (LV) surface area and LV weight in cold-exposed rats, suggesting LV hypertrophy. Superoxide production in the heart was increased by cold exposure. Interestingly, ET1-shRNA prevented cold-induced superoxide production and cardiac hypertrophy. ELISA assay indicated that ET1-shRNA abolished the cold-induced upregulation of ET1 levels, indicating effective silencing of ET1. In conclusion, upregulation of ET1 plays a critical role in the pathogenesis of CIH and cardiac hypertrophy. AAV delivery of ET1-shRNA is an effective therapeutic strategy for cold-related cardiovascular disease.
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Affiliation(s)
- Peter Gin-Fu Chen
- 2 Departments of Medicine and Physiology, College of Medicine, University of Florida , Gainesville, Florida
| | - Zhongjie Sun
- 1 Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center , Oklahoma City, Oklahoma.,2 Departments of Medicine and Physiology, College of Medicine, University of Florida , Gainesville, Florida
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11
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Varshney R, Ali Q, Wu C, Sun Z. Monocrotaline-Induced Pulmonary Hypertension Involves Downregulation of Antiaging Protein Klotho and eNOS Activity. Hypertension 2016; 68:1255-1263. [PMID: 27672025 DOI: 10.1161/hypertensionaha.116.08184] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2016] [Accepted: 08/15/2016] [Indexed: 12/20/2022]
Abstract
The objective of this study is to investigate whether stem cell delivery of secreted Klotho (SKL), an aging-suppressor protein, attenuates monocrotaline-induced pulmonary vascular dysfunction and remodeling. Overexpression of SKL in mesenchymal stem cells (MSCs) was achieved by transfecting MSCs with lentiviral vectors expressing SKL-green fluorescent protein (GFP). Four groups of rats were treated with monocrotaline, whereas an additional group was given saline (control). Three days later, 4 monocrotaline-treated groups received intravenous delivery of nontransfected MSCs, MSC-GFP, MSC-SKL-GFP, and PBS, respectively. Ex vivo vascular relaxing responses to acetylcholine were diminished in small pulmonary arteries (PAs) in monocrotaline-treated rats, indicating pulmonary vascular endothelial dysfunction. Interestingly, delivery of MSCs overexpressing SKL (MSC-SKL-GFP) abolished monocrotaline-induced pulmonary vascular endothelial dysfunction and PA remodeling. Monocrotaline significantly increased right ventricular systolic blood pressure, which was attenuated significantly by MSC-SKL-GFP, indicating improved PA hypertension. MSC-SKL-GFP also attenuated right ventricular hypertrophy. Nontransfected MSCs slightly, but not significantly, improved PA hypertension and pulmonary vascular endothelial dysfunction. MSC-SKL-GFP attenuated monocrotaline-induced inflammation, as evidenced by decreased macrophage infiltration around PAs. MSC-SKL-GFP increased SKL levels, which rescued the downregulation of SIRT1 (Sirtuin 1) expression and endothelial NO synthase (eNOS) phosphorylation in the lungs of monocrotaline-treated rats. In cultured endothelial cells, SKL abolished monocrotaline-induced downregulation of eNOS activity and NO levels and enhanced cell viability. Therefore, stem cell delivery of SKL is an effective therapeutic strategy for pulmonary vascular endothelial dysfunction and PA remodeling. SKL attenuates monocrotaline-induced PA remodeling and PA smooth muscle cell proliferation, likely by reducing inflammation and restoring SIRT1 levels and eNOS activity.
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Affiliation(s)
- Rohan Varshney
- From the Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City
| | - Quaisar Ali
- From the Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City
| | - Chengxiang Wu
- From the Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City
| | - Zhongjie Sun
- From the Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City.
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12
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Gao D, Zuo Z, Tian J, Ali Q, Lin Y, Lei H, Sun Z. Activation of SIRT1 Attenuates Klotho Deficiency-Induced Arterial Stiffness and Hypertension by Enhancing AMP-Activated Protein Kinase Activity. Hypertension 2016; 68:1191-1199. [PMID: 27620389 DOI: 10.1161/hypertensionaha.116.07709] [Citation(s) in RCA: 106] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2016] [Accepted: 08/17/2016] [Indexed: 12/27/2022]
Abstract
Arterial stiffness is an independent risk factor for stroke and myocardial infarction. This study was designed to investigate the role of SIRT1, an important deacetylase, and its relationship with Klotho, a kidney-derived aging-suppressor protein, in the pathogenesis of arterial stiffness and hypertension. We found that the serum level of Klotho was decreased by ≈45% in patients with arterial stiffness and hypertension. Interestingly, Klotho haplodeficiency caused arterial stiffening and hypertension, as evidenced by significant increases in pulse wave velocity and blood pressure in Klotho-haplodeficient (KL+/-) mice. Notably, the expression and activity of SIRT1 were decreased significantly in aortic endothelial and smooth muscle cells in KL+/- mice, suggesting that Klotho deficiency downregulates SIRT1. Treatment with SRT1720 (15 mg/kg/d, IP), a specific SIRT1 activator, abolished Klotho deficiency-induced arterial stiffness and hypertension in KL+/- mice. Klotho deficiency was associated with significant decreases in activities of AMP-activated protein kinase α (AMPKα) and endothelial NO synthase (eNOS) in aortas, which were abolished by SRT1720. Furthermore, Klotho deficiency upregulated NADPH oxidase activity and superoxide production, increased collagen expression, and enhanced elastin fragmentation in the media of aortas. These Klotho deficiency-associated changes were blocked by SRT1720. In conclusion, this study provides the first evidence that Klotho deficiency downregulates SIRT1 activity in arterial endothelial and smooth muscle cells. Pharmacological activation of SIRT1 may be an effective therapeutic strategy for arterial stiffness and hypertension.
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Affiliation(s)
- Diansa Gao
- From the Department of Cardiology (D.G., Z.Z., H.L., Z.S.) and Department of Physical Examination (J.T.), the First Affiliated Hospital, Chongqing Medical University, China; and Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City (D.G., Q.A., Y.L., Z.S.)
| | - Zhong Zuo
- From the Department of Cardiology (D.G., Z.Z., H.L., Z.S.) and Department of Physical Examination (J.T.), the First Affiliated Hospital, Chongqing Medical University, China; and Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City (D.G., Q.A., Y.L., Z.S.)
| | - Jing Tian
- From the Department of Cardiology (D.G., Z.Z., H.L., Z.S.) and Department of Physical Examination (J.T.), the First Affiliated Hospital, Chongqing Medical University, China; and Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City (D.G., Q.A., Y.L., Z.S.)
| | - Quaisar Ali
- From the Department of Cardiology (D.G., Z.Z., H.L., Z.S.) and Department of Physical Examination (J.T.), the First Affiliated Hospital, Chongqing Medical University, China; and Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City (D.G., Q.A., Y.L., Z.S.)
| | - Yi Lin
- From the Department of Cardiology (D.G., Z.Z., H.L., Z.S.) and Department of Physical Examination (J.T.), the First Affiliated Hospital, Chongqing Medical University, China; and Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City (D.G., Q.A., Y.L., Z.S.)
| | - Han Lei
- From the Department of Cardiology (D.G., Z.Z., H.L., Z.S.) and Department of Physical Examination (J.T.), the First Affiliated Hospital, Chongqing Medical University, China; and Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City (D.G., Q.A., Y.L., Z.S.)
| | - Zhongjie Sun
- From the Department of Cardiology (D.G., Z.Z., H.L., Z.S.) and Department of Physical Examination (J.T.), the First Affiliated Hospital, Chongqing Medical University, China; and Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City (D.G., Q.A., Y.L., Z.S.).
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Zhou X, Chen K, Wang Y, Schuman M, Lei H, Sun Z. Antiaging Gene Klotho Regulates Adrenal CYP11B2 Expression and Aldosterone Synthesis. J Am Soc Nephrol 2015; 27:1765-76. [PMID: 26471128 DOI: 10.1681/asn.2015010093] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2015] [Accepted: 08/27/2015] [Indexed: 12/11/2022] Open
Abstract
Deficiency of the antiaging gene Klotho (KL) induces renal damage and hypertension through unknown mechanisms. In this study, we assessed whether KL regulates expression of CYP11B2, a key rate-limiting enzyme in aldosterone synthesis, in adrenal glands. We found that haplodeficiency of KL(+/-) in mice increased the plasma level of aldosterone by 16 weeks of age, which coincided with spontaneous and persistent elevation of BP. Blockade of aldosterone actions by eplerenone reversed KL deficiency-induced hypertension and attenuated the kidney damage. Protein expression of CYP11B2 was upregulated in adrenal cortex of KL(+/-) mice. KL and CYP11B2 proteins colocalized in adrenal zona glomerulosa cells. Silencing of KL upregulated and overexpression of KL downregulated CYP11B2 expression in human adrenocortical cells. Notably, silencing of KL decreased expression of SF-1, a negative transcription factor of CYP11B2, but increased phosphorylation of ATF2, a positive transcription factor of CYP11B2, which may contribute to upregulation of CYP11B2 expression. Therefore, these results show that KL regulates adrenal CYP11B2 expression. KL deficiency-induced spontaneous hypertension and kidney damage may be partially attributed to the upregulation of CYP11B2 expression and aldosterone synthesis.
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Affiliation(s)
- Xiaoli Zhou
- Department of Cardiology, First Affiliated Hospital, Chongqing Medical University, Chongqing, China; and Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Kai Chen
- Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Yongjun Wang
- Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Mariano Schuman
- Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
| | - Han Lei
- Department of Cardiology, First Affiliated Hospital, Chongqing Medical University, Chongqing, China; and
| | - Zhongjie Sun
- Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma
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Chen K, Zhou X, Sun Z. Haplodeficiency of Klotho Gene Causes Arterial Stiffening via Upregulation of Scleraxis Expression and Induction of Autophagy. Hypertension 2015; 66:1006-13. [PMID: 26324504 DOI: 10.1161/hypertensionaha.115.06033] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2015] [Accepted: 08/09/2015] [Indexed: 12/11/2022]
Abstract
The prevalence of arterial stiffness increases with age, whereas the level of the aging-suppressor protein klotho decreases with age. The objective of this study is to assess whether haplodeficiency of klotho gene causes arterial stiffness and to investigate the underlying mechanism. Pulse wave velocity, a direct measure of arterial stiffness, was increased significantly in klotho heterozygous (klotho(+/-)) mice versus their age-matched wild-type (WT) littermates, suggesting that haplodeficiency of klotho causes arterial stiffening. Notably, plasma aldosterone levels were elevated significantly in klotho(+/-) mice. Treatment with eplerenone (6 mg/kg per day IP), an aldosterone receptor blocker, abolished klotho deficiency-induced arterial stiffening in klotho(+/-) mice. Klotho deficiency was associated with increased collagen and decreased elastin contents in the media of aortas. In addition, arterial matrix metalloproteinase-2, matrix metalloproteinase-9, and transforming growth factor-β1 expression and myofibroblast differentiation were increased in klotho(+/-) mice. These klotho deficiency-related changes can be blocked by eplerenone. Protein expression of scleraxis, a transcription factor for collagen synthesis, and LC3-II/LC3-I, an index of autophagy, were upregulated in aortas of klotho(+/-) mice, which can be abolished by eplerenone. In cultured mouse aortic smooth muscle cells, aldosterone increased collagen-1 expression that can be completely eliminated by small interfering RNA knockdown of scleraxis. Interestingly, aldosterone decreased elastin levels in smooth muscle cells, which can be abolished by small interfering RNA knockdown of Beclin-1, an autophagy-related gene. In conclusion, this study demonstrated for the first time that klotho deficiency-induced arterial stiffening may involve aldosterone-mediated upregulation of scleraxis and induction of autophagy, which led to increased collagen-1 expression and decreased elastin levels, respectively.
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Affiliation(s)
- Kai Chen
- From the Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City (K.C., X.Z., Z.S.); and Department of Cardiology, the First Affiliated Hospital, Chongqing Medical University, Chongqing, China (X.Z.)
| | - Xiaoli Zhou
- From the Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City (K.C., X.Z., Z.S.); and Department of Cardiology, the First Affiliated Hospital, Chongqing Medical University, Chongqing, China (X.Z.)
| | - Zhongjie Sun
- From the Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City (K.C., X.Z., Z.S.); and Department of Cardiology, the First Affiliated Hospital, Chongqing Medical University, Chongqing, China (X.Z.).
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15
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Lin Y, Sun Z. In vivo pancreatic β-cell-specific expression of antiaging gene Klotho: a novel approach for preserving β-cells in type 2 diabetes. Diabetes 2015; 64:1444-58. [PMID: 25377875 PMCID: PMC4375073 DOI: 10.2337/db14-0632] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Protein expression of an antiaging gene, Klotho, was depleted in pancreatic islets in patients with type 2 diabetes mellitus (T2DM) and in db/db mice, an animal model of T2DM. The objective of this study was to investigate whether in vivo expression of Klotho would preserve pancreatic β-cell function in db/db mice. We report for the first time that β-cell-specific expression of Klotho attenuated the development of diabetes in db/db mice. β-Cell-specific expression of Klotho decreased hyperglycemia and enhanced glucose tolerance. The beneficial effects of Klotho were associated with significant improvements in T2DM-induced decreases in number of β-cells, insulin storage levels in pancreatic islets, and glucose-stimulated insulin secretion from pancreatic islets, which led to increased blood insulin levels in diabetic mice. In addition, β-cell-specific expression of Klotho decreased intracellular superoxide levels, oxidative damage, apoptosis, and DNAJC3 (a marker for endoplasmic reticulum stress) in pancreatic islets. Furthermore, β-cell-specific expression of Klotho increased expression levels of Pdx-1 (insulin transcription factor), PCNA (a marker of cell proliferation), and LC3 (a marker of autophagy) in pancreatic islets in db/db mice. These results reveal that β-cell-specific expression of Klotho improves β-cell function and attenuates the development of T2DM. Therefore, in vivo expression of Klotho may offer a novel strategy for protecting β-cells in T2DM.
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Affiliation(s)
- Yi Lin
- Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK
| | - Zhongjie Sun
- Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, Oklahoma City, OK
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16
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Crosswhite P, Chen K, Sun Z. AAV delivery of tumor necrosis factor-α short hairpin RNA attenuates cold-induced pulmonary hypertension and pulmonary arterial remodeling. Hypertension 2014; 64:1141-50. [PMID: 25185133 DOI: 10.1161/hypertensionaha.114.03791] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Cold temperatures are associated with increased mortality and morbidity of cardiovascular and pulmonary disease. Cold exposure causes lung inflammation, pulmonary hypertension (PH), and right ventricle hypertrophy, but there is no effective therapy because of unknown mechanism. Here, we investigated whether RNA interference silencing of tumor necrosis factor (TNF)-α decreases cold-induced macrophage infiltration, PH, and pulmonary arterial (PA) remodeling. We found for the first time that continuous cold exposure (5.0°C) increased TNF-α expression and macrophage infiltration in the lungs and PAs right before elevation of right ventricle systolic pressure. The in vivo RNA interference silencing of TNF-α was achieved by intravenous delivery of recombinant AAV-2 carrying TNF-α short hairpin small-interfering RNA 24 hours before cold exposure. Cold exposure for 8 weeks significantly increased right ventricle pressure compared with the warm controls (40.19±4.9 versus 22.9±1.1 mm Hg), indicating that cold exposure caused PH. Cold exposure increased TNF-α, interleukin-6, and phosphodiesterase-1C protein expression in the lungs and PAs and increased lung macrophage infiltration. Notably, TNF-α short hairpin small-interfering RNA prevented the cold-induced increases in TNF-α, interleukin-6, and phosphodiesterase-1C protein expression, abolished lung macrophage infiltration, and attenuated PH (26.28±1.6 mm Hg), PA remodeling, and right ventricle hypertrophy. PA smooth muscle cells isolated from cold-exposed animals showed increased intracellular superoxide levels and cell proliferation along with decreased intracellular cGMP. These cold-induced changes were prevented by TNF-α short hairpin small-interfering RNA. In conclusions, upregulation of TNF-α played a critical role in the pathogenesis of cold-induced PH by promoting pulmonary macrophage infiltration and inflammation. AAV delivery of TNF-α short hairpin small-interfering RNA may be an effective therapeutic approach for cold-induced PH and PA remodeling.
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Affiliation(s)
- Patrick Crosswhite
- From the Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center
| | - Kai Chen
- From the Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center
| | - Zhongjie Sun
- From the Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center.
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Lin Y, Kuro-o M, Sun Z. Genetic deficiency of anti-aging gene klotho exacerbates early nephropathy in STZ-induced diabetes in male mice. Endocrinology 2013; 154:3855-63. [PMID: 23928372 PMCID: PMC3776873 DOI: 10.1210/en.2013-1053] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Klotho is a recently discovered anti-aging gene and is primarily expressed in kidneys. In humans, the klotho level decreases with age whereas the prevalence of chronic kidney disease (CKD) increases with age. Diabetic nephropathy is the most common form of CKD, which leads to end-stage renal disease. A decrease in klotho has been found in kidneys of patients with diabetic nephropathy. The purpose of this study is to assess whether klotho gene deficiency affects early diabetic nephropathy in a mouse of model of type 1 diabetes induced by streptozotocin (STZ). Male KL(+/-) mutant and wild-type mice (6-8 weeks) were injected with multiple low doses of STZ. Renal functions and renal blood flow were assessed. Kidneys were collected for histological examination and molecular assays of TGFβ1 and mammalian targets of rapamycin (mTOR) signaling. Klotho deficiency in KL(+/-) mutant mice exacerbated STZ-induced increases in urine albumin, blood urea nitrogen, expansion of mesangial matrix in renal glomeruli, and kidney hypertrophy, suggesting a protective role of klotho in kidney function and structure. Klotho deficiency did not affect renal blood flow. Notably, klotho deficiency significantly increased phosphorylation of Smad2, indicating enhanced TGFβ1 signaling in kidneys. Klotho deficiency also increased phosphorylation of mTOR and S6 (a downstream effector of mTOR), indicating enhanced mTOR signaling in kidneys of early diabetic mice. Thus, klotho gene deficiency may make kidneys more susceptible to diabetic injury. Klotho gene deficiency exacerbated early diabetic nephropathy via enhancing both TGFβ1 and mTOR signaling in kidneys.
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Affiliation(s)
- Yi Lin
- MD, PhD, FAHA, Professor of Physiology, Director, The Robert and Mary Cade Laboratory, BMSB 662A, Box 26901, Department of Physiology, College of Medicine, University of Oklahoma Health Sciences Center, 940 S. L. Young Boulevard, Oklahoma City, OK 73126-0901.
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