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Pham DL, Niemi A, Blank R, Lomenzo G, Tham J, Ko ML, Ko GYP. Peptide Lv Promotes Trafficking and Membrane Insertion of K Ca3.1 through the MEK1-ERK and PI3K-Akt Signaling Pathways. Cells 2023; 12:1651. [PMID: 37371121 PMCID: PMC10296961 DOI: 10.3390/cells12121651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 06/09/2023] [Accepted: 06/15/2023] [Indexed: 06/29/2023] Open
Abstract
Peptide Lv is a small endogenous secretory peptide that is proangiogenic through hyperpolarizing vascular endothelial cells (ECs) by enhancing the current densities of KCa3.1 channels. However, it is unclear how peptide Lv enhances these currents. One way to enhance the current densities of ion channels is to promote its trafficking and insertion into the plasma membrane. We hypothesized that peptide Lv-elicited KCa3.1 augmentation occurs through activating the mitogen-activated protein kinase kinase 1 (MEK1)-extracellular signal-regulated kinase (ERK) and phosphoinositide 3-kinase (PI3K)-protein kinase B (Akt) signaling pathways, which are known to mediate ion channel trafficking and membrane insertion in neurons. To test this hypothesis, we employed patch-clamp electrophysiological recordings and cell-surface biotinylation assays on ECs treated with peptide Lv and pharmaceutical inhibitors of ERK and Akt. Blocking ERK or Akt activation diminished peptide Lv-elicited EC hyperpolarization and increase in KCa3.1 current densities. Blocking PI3K or Akt activation decreased the level of plasma membrane-bound, but not the total amount of KCa3.1 protein in ECs. Therefore, the peptide Lv-elicited EC hyperpolarization and KCa3.1 augmentation occurred in part through channel trafficking and insertion mediated by MEK1-ERK and PI3K-Akt activation. These results demonstrate the molecular mechanisms of how peptide Lv promotes EC-mediated angiogenesis.
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Affiliation(s)
- Dylan L. Pham
- Department of Veterinary Integrative Biosciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; (D.L.P.); (A.N.); (R.B.); (G.L.); (J.T.); (M.L.K.)
| | - Autumn Niemi
- Department of Veterinary Integrative Biosciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; (D.L.P.); (A.N.); (R.B.); (G.L.); (J.T.); (M.L.K.)
| | - Ria Blank
- Department of Veterinary Integrative Biosciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; (D.L.P.); (A.N.); (R.B.); (G.L.); (J.T.); (M.L.K.)
| | - Gabriella Lomenzo
- Department of Veterinary Integrative Biosciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; (D.L.P.); (A.N.); (R.B.); (G.L.); (J.T.); (M.L.K.)
| | - Jenivi Tham
- Department of Veterinary Integrative Biosciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; (D.L.P.); (A.N.); (R.B.); (G.L.); (J.T.); (M.L.K.)
| | - Michael L. Ko
- Department of Veterinary Integrative Biosciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; (D.L.P.); (A.N.); (R.B.); (G.L.); (J.T.); (M.L.K.)
- Department of Biology, Division of Natural and Physical Sciences, Blinn College, Bryan, TX 77802, USA
| | - Gladys Y.-P. Ko
- Department of Veterinary Integrative Biosciences, School of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX 77843, USA; (D.L.P.); (A.N.); (R.B.); (G.L.); (J.T.); (M.L.K.)
- Texas A&M Institute for Neuroscience, Texas A&M University, College Station, TX 77843, USA
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Chang JYA, Yu F, Shi L, Ko ML, Ko GYP. Melatonin Affects Mitochondrial Fission/Fusion Dynamics in the Diabetic Retina. J Diabetes Res 2019; 2019:8463125. [PMID: 31098384 PMCID: PMC6487082 DOI: 10.1155/2019/8463125] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 01/14/2019] [Accepted: 02/10/2019] [Indexed: 02/07/2023] Open
Abstract
Mitochondrial fission and fusion are dependent on cellular nutritional states, and maintaining this dynamics is critical for the health of cells. Starvation triggers mitochondrial fusion to maintain bioenergetic efficiency, but during nutrient overloads (as with hyperglycemic conditions), fragmenting mitochondria is a way to store nutrients to avoid waste of energy. In addition to ATP production, mitochondria play an important role in buffering intracellular calcium (Ca2+). We found that in cultured 661W cells, a photoreceptor-derived cell line, hyperglycemic conditions triggered an increase of the expression of dynamin-related protein 1 (DRP1), a protein marker of mitochondrial fission, and a decrease of mitofusin 2 (MFN2), a protein for mitochondrial fusion. Further, these hyperglycemic cells also had decreased mitochondrial Ca2+ but increased cytosolic Ca2+. Treating these hyperglycemic cells with melatonin, a multifaceted antioxidant, averted hyperglycemia-altered mitochondrial fission-and-fusion dynamics and mitochondrial Ca2+ levels. To mimic how people most commonly take melatonin supplements, we gave melatonin to streptozotocin- (STZ-) induced type 1 diabetic mice by daily oral gavage and determined the effects of melatonin on diabetic eyes. We found that melatonin was not able to reverse the STZ-induced systemic hyperglycemic condition, but it prevented STZ-induced damage to the neural retina and retinal microvasculature. The beneficial effects of melatonin in the neural retina in part were through alleviating STZ-caused changes in mitochondrial dynamics and Ca2+ buffering.
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Affiliation(s)
- Janet Ya-An Chang
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
- Interdisciplinary Toxicology Program, Texas A&M University, College Station, Texas, USA
| | - Fei Yu
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
| | - Liheng Shi
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
| | - Michael L. Ko
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
| | - Gladys Y.-P. Ko
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas, USA
- Interdisciplinary Toxicology Program, Texas A&M University, College Station, Texas, USA
- Texas A&M Institute of Neuroscience, Texas A&M University, College Station, Texas, USA
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Shi L, Ko ML, Huang CCY, Park SY, Hong MP, Wu C, Ko GYP. Chicken embryos as a potential new model for early onset type I diabetes. J Diabetes Res 2014; 2014:354094. [PMID: 25133191 PMCID: PMC4122024 DOI: 10.1155/2014/354094] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2014] [Accepted: 06/26/2014] [Indexed: 11/18/2022] Open
Abstract
Diabetic retinopathy (DR) is the leading cause of blindness among the American working population. The purpose of this study is to establish a new diabetic animal model using a cone-dominant avian species to address the distorted color vision and altered cone pathway responses in prediabetic and early diabetic patients. Chicken embryos were injected with either streptozotocin (STZ), high concentration of glucose (high-glucose), or vehicle at embryonic day 11. Cataracts occurred in varying degrees in both STZ- and high glucose-induced diabetic chick embryos at E18. Streptozotocin-diabetic chicken embryos had decreased levels of blood insulin, glucose transporter 4 (Glut4), and phosphorylated protein kinase B (pAKT). In STZ-injected E20 embryos, the ERG amplitudes of both a- and b-waves were significantly decreased, the implicit time of the a-wave was delayed, while that of the b-wave was significantly increased. Photoreceptors cultured from STZ-injected E18 embryos had a significant decrease in L-type voltage-gated calcium channel (L-VGCC) currents, which was reflected in the decreased level of L-VGCCα1D subunit in the STZ-diabetic retinas. Through these independent lines of evidence, STZ-injection was able to induce pathological conditions in the chicken embryonic retina, and it is promising to use chickens as a potential new animal model for type I diabetes.
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Affiliation(s)
- Liheng Shi
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX 77843-4458, USA
| | - Michael L. Ko
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX 77843-4458, USA
| | - Cathy Chia-Yu Huang
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX 77843-4458, USA
| | - So-Young Park
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX 77843-4458, USA
| | - Min-Pyo Hong
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX 77843-4458, USA
| | - Chaodong Wu
- Department of Nutrition, Texas A&M University, College Station, TX 77843-4458, USA
| | - Gladys Y.-P. Ko
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, 4458 TAMU, College Station, TX 77843-4458, USA
- Texas A&M Institute of Neuroscience, Texas A&M University, College Station, TX 77843-445, USA
- *Gladys Y.-P. Ko:
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Ko ML, Shi L, Tsai JY, Young ME, Neuendorff N, Earnest DJ, Ko GYP. Cardiac-specific mutation of Clock alters the quantitative measurements of physical activities without changing behavioral circadian rhythms. J Biol Rhythms 2011; 26:412-22. [PMID: 21921295 PMCID: PMC3181102 DOI: 10.1177/0748730411414170] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Even though peripheral circadian oscillators in the cardiovascular system are known to exist, the daily rhythms of the cardiovascular system are mainly attributed to autonomic or hormonal inputs under the control of the central oscillator, the suprachiasmatic nucleus (SCN). In order to examine the role of peripheral oscillators in the cardiovascular system, we used a transgenic mouse where the Clock gene is specifically disrupted in cardiomyocytes. In this cardiomyocyte-specific CLOCK mutant (CCM) mouse model, the circadian input from the SCN remains intact. Both CCM and wild-type (WT) littermates displayed circadian rhythms in wheel-running behavior. However, the overall wheel-running activities were significantly lower in CCM mice compared to WT over the course of 5 weeks, indicating that CCM mice either have lower baseline physical activities or they have lower physical adaptation abilities because daily wheel running, like routine exercise, induces physical adaptation over a period of time. Upon further biochemical analysis, it was revealed that the diurnal oscillations of phosphorylation states of several kinases and protein expression of the L-type voltage-gated calcium channel (L-VGCC) α1D subunit found in WT hearts were abolished in CCM hearts, indicating that in mammalian hearts, the daily oscillations of the activities of these kinases and L-VGCCs were downstream elements of the cardiac core oscillators. However, the phosphorylation of p38 MAPK exhibited robust diurnal rhythms in both WT and CCM hearts, indicating that cardiac p38 could be under the influence of the central clock through neurohormonal signals or be part of the circadian input pathway in cardiomyocytes. Taken together, these results indicate that the cardiac core oscillators have an impact in regulating circadian rhythmicities and cardiac function.
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Affiliation(s)
- Michael L. Ko
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
| | - Liheng Shi
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
| | - Ju-Yun Tsai
- US Department of Agriculture/Agricultural Research Service Children’s Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, TX
| | - Martin E. Young
- Division of Cardiovascular Diseases, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL
| | - Nichole Neuendorff
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College Station, TX
| | - David J. Earnest
- Department of Neuroscience and Experimental Therapeutics, Texas A&M Health Science Center, College Station, TX
| | - Gladys Y.-P. Ko
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX
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Chae KS, Ko GYP, Dryer SE. Tyrosine phosphorylation of cGMP-gated ion channels is under circadian control in chick retina photoreceptors. Invest Ophthalmol Vis Sci 2007; 48:901-6. [PMID: 17251493 PMCID: PMC2376765 DOI: 10.1167/iovs.06-0824] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To investigate the role of tyrosine phosphorylation in circadian regulation of cGMP-gated cation channels (CNGCs) of chicken cone photoreceptors. METHODS Chick retinas were studied on the second day of constant darkness (DD) after several days of entrainment to 12:12 hr light-dark (LD) cycles in vitro. Inside-out patch recordings were made during the subjective day and subjective night to quantify circadian changes in the sensitivity of CNGCs to activation by cGMP after treatment with various tyrosine kinase and tyrosine phosphatase inhibitors. Immunoprecipitation and immunoblot analysis were also used to examine tyrosine phosphorylation of CNGCs and closely associated proteins after separation by conventional and two-dimensional SDS-PAGE. RESULTS Treatment with tyrosine kinase inhibitors caused a significant decrease in K(1/2) for cGMP activation of CNGCs in patches excised from cones during the subjective day, but had no effect on K(1/2) during the subjective night. Conversely, treatment with a tyrosine phosphatase inhibitor caused a significant increase in the K(1/2) of CNGCs in patches excised during the subjective night but had no effect on channel K(1/2) during the subjective day. Broad spectrum serine-threonine phosphatase inhibitors had no effect. An 85-kDa tyrosine polypeptide that coimmunoprecipitated with CNGC alpha-subunits was detectable at higher levels during the subjective day than during the subjective night. CNGC alpha-subunits were not tyrosine phosphorylated as a function of the time of day. CONCLUSIONS Circadian control of cone CNGCs appears to entail elevated daytime tyrosine phosphorylation of an approximately 85-kDa auxiliary protein or another subunit of the CNGCs.
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Affiliation(s)
- Kwon-Seok Chae
- From the School of Life Sciences and Biotechnology, Korea University, Seoul, Korea; the
| | - Gladys Y.-P. Ko
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas; and the
| | - Stuart E. Dryer
- Department of Biology and Biochemistry, University of Houston, Houston, Texas
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