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Chen J, Zhang L, Zhu Y, Zhao D, Zhang J, Zhu Y, Pang J, Xiao Y, Wu Q, Wang Y, Zhan Q. AKT2 S128/CCTα S315/319/323-positive cancer-associated fibroblasts (CAFs) mediate focal adhesion kinase (FAK) inhibitors resistance via secreting phosphatidylcholines (PCs). Signal Transduct Target Ther 2024; 9:21. [PMID: 38280862 PMCID: PMC10821909 DOI: 10.1038/s41392-023-01728-6] [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: 07/07/2023] [Revised: 10/26/2023] [Accepted: 12/10/2023] [Indexed: 01/29/2024] Open
Abstract
Abnormal metabolism is regarded as an oncogenic hallmark related to tumor progression and therapeutic resistance. Present study employed multi-omics, including phosphoproteomics, untargeted metabolomics and lipidomics, to demonstrate that the pAKT2 Ser128 and pCCTα Ser315/319/323-positive cancer-associated fibroblasts (CAFs) substantially release phosphatidylcholines (PCs), contributing to the resistance of focal adhesion kinase (FAK) inhibitors in esophageal squamous cell carcinoma (ESCC) treatment. Additionally, we observed extremely low levels of FAK Tyr397 expression in CAFs, potentially offering no available target for FAK inhibitors playing their anti-growth role in CAFs. Consequently, FAK inhibitor increased the intracellular concentration of Ca2+ in CAFs, promoting the formation of AKT2/CCTα complex, leading to phosphorylation of CCTα Ser315/319/323 sites and eventually enhancing stromal PC production. This activation could stimulate the intratumoral Janus kinase 2 (JAK2)/Signal transducer and activator of transcription 3 (STAT3) pathway, triggering resistance to FAK inhibition. Analysis of clinical samples demonstrated that stromal pAKT2 Ser128 and pCCTα Ser315/319/323 are related to the tumor malignancy and reduced patient survival. Pseudo-targeted lipidomics and further validation cohort quantitatively showed that plasma PCs enable to distinguish the malignant extent of ESCC patients. In conclusion, inhibition of stroma-derived PCs and related pathway could be possible therapeutic strategies for tumor therapy.
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Affiliation(s)
- Jie Chen
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, 100142, Beijing, China.
- Peking University International Cancer Institute, Peking University, 100191, Beijing, China.
- Research Unit of Molecular Cancer Research, Chinese Academy of Medical Sciences, Beijing, China.
- Soochow University Cancer Institute, Suzhou, 215000, China.
| | - Lingyuan Zhang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, 100142, Beijing, China
- Peking University International Cancer Institute, Peking University, 100191, Beijing, China
- Research Unit of Molecular Cancer Research, Chinese Academy of Medical Sciences, Beijing, China
| | - Yuheng Zhu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, 100142, Beijing, China
| | - Di Zhao
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, 100142, Beijing, China
- Peking University International Cancer Institute, Peking University, 100191, Beijing, China
- Research Unit of Molecular Cancer Research, Chinese Academy of Medical Sciences, Beijing, China
| | - Jing Zhang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, 100142, Beijing, China
- Peking University International Cancer Institute, Peking University, 100191, Beijing, China
- Research Unit of Molecular Cancer Research, Chinese Academy of Medical Sciences, Beijing, China
| | - Yanmeng Zhu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, 100142, Beijing, China
- Peking University International Cancer Institute, Peking University, 100191, Beijing, China
- Research Unit of Molecular Cancer Research, Chinese Academy of Medical Sciences, Beijing, China
| | - Jingyuan Pang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, 100142, Beijing, China
| | - Yuanfan Xiao
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, 100142, Beijing, China
- Peking University International Cancer Institute, Peking University, 100191, Beijing, China
- Research Unit of Molecular Cancer Research, Chinese Academy of Medical Sciences, Beijing, China
| | - Qingnan Wu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, 100142, Beijing, China
- Peking University International Cancer Institute, Peking University, 100191, Beijing, China
- Research Unit of Molecular Cancer Research, Chinese Academy of Medical Sciences, Beijing, China
| | - Yan Wang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, 100142, Beijing, China
- Peking University International Cancer Institute, Peking University, 100191, Beijing, China
- Research Unit of Molecular Cancer Research, Chinese Academy of Medical Sciences, Beijing, China
| | - Qimin Zhan
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Laboratory of Molecular Oncology, Peking University Cancer Hospital & Institute, 100142, Beijing, China.
- Peking University International Cancer Institute, Peking University, 100191, Beijing, China.
- Research Unit of Molecular Cancer Research, Chinese Academy of Medical Sciences, Beijing, China.
- Soochow University Cancer Institute, Suzhou, 215000, China.
- Institute of Cancer Research, Shenzhen Bay Laboratory, Shenzhen, 518107, China.
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Takita Y, Sugano E, Kitabayashi K, Tabata K, Saito A, Yokoyama T, Onoguchi R, Fukuda T, Ozaki T, Bai L, Tomita H. Evaluation of Local Retinal Function in Light-Damaged Rats Using Multifocal Electroretinograms and Multifocal Visual Evoked Potentials. Int J Mol Sci 2023; 24:16433. [PMID: 38003623 PMCID: PMC10670973 DOI: 10.3390/ijms242216433] [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: 10/19/2023] [Revised: 11/09/2023] [Accepted: 11/15/2023] [Indexed: 11/26/2023] Open
Abstract
Electroretinograms (ERGs) are often used to evaluate retinal function. However, assessing local retinal function can be challenging; therefore, photopic and scotopic ERGs are used to record whole-retinal function. This study evaluated focal retinal function in rats exposed to continuous light using a multifocal ERG (mfERG) system. The rats were exposed to 1000 lux of fluorescent light for 24 h to induce photoreceptor degeneration. After light exposure, the rats were reared under cyclic light conditions (12 h: 5 lux, 12 h: dark). Photopic and multifocal ERGs and single-flash and multifocal visual evoked potentials (mfVEPs) were recorded 7 days after light exposure. Fourteen days following light exposure, paraffin-embedded sections were prepared from the eyes for histological evaluation. The ERG and VEP responses dramatically decreased after 24 h of light exposure, and retinal area-dependent decreases were observed in mfERGs and mfVEPs. Histological assessment revealed severe damage to the superior retina and less damage to the inferior retina. Considering the recorded visual angles of mfERGs and mfVEPs, the degenerated area shown on the histological examinations correlates well with the responses from multifocal recordings.
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Grants
- 21-Ⅱ4001 Terumo (Japan)
- 22H00579 Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan
- 21K18278 Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan
- 22K09760 Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan
- 21K09713 Grants-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology, Japan
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Hiroshi Tomita
- Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University Division of Science and Engineering, 4-3-5 Ueda, Morioka 020-8551, Iwate, Japan; (Y.T.); (E.S.); (K.K.); (K.T.); (A.S.); (T.Y.); (R.O.); (T.F.); (T.O.); (L.B.)
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3
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Rajala A, Bhat MA, Teel K, Gopinadhan Nair GK, Purcell L, Rajala RVS. The function of lactate dehydrogenase A in retinal neurons: implications to retinal degenerative diseases. PNAS NEXUS 2023; 2:pgad038. [PMID: 36896135 PMCID: PMC9991461 DOI: 10.1093/pnasnexus/pgad038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 01/28/2023] [Accepted: 01/31/2023] [Indexed: 02/05/2023]
Abstract
The postmitotic retina is highly metabolic and the photoreceptors depend on aerobic glycolysis for an energy source and cellular anabolic activities. Lactate dehydrogenase A (LDHA) is a key enzyme in aerobic glycolysis, which converts pyruvate to lactate. Here we show that cell-type-specific actively translating mRNA purification by translating ribosome affinity purification shows a predominant expression of LDHA in rods and cones and LDHB in the retinal pigment epithelium and Müller cells. We show that genetic ablation of LDHA in the retina resulted in diminished visual function, loss of structure, and a loss of dorsal-ventral patterning of the cone-opsin gradient. Loss of LDHA in the retina resulted in increased glucose availability, promoted oxidative phosphorylation, and upregulated the expression of glutamine synthetase (GS), a neuron survival factor. However, lacking LDHA in Müller cells does not affect visual function in mice. Glucose shortage is associated with retinal diseases, such as age-related macular degeneration (AMD), and regulating the levels of LDHA may have therapeutic relevance. These data demonstrate the unique and unexplored roles of LDHA in the maintenance of a healthy retina.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
- Dean McGee Eye Institute, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
| | - Mohd A Bhat
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
- Dean McGee Eye Institute, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
| | - Kenneth Teel
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
- Dean McGee Eye Institute, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
| | - Gopa Kumar Gopinadhan Nair
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
- Dean McGee Eye Institute, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
| | - Lindsey Purcell
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
- Dean McGee Eye Institute, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
| | - Raju V S Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
- Dean McGee Eye Institute, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
- Department of Cell Biology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma City, OK 73104, USA
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Liu H, Stepicheva NA, Ghosh S, Shang P, Chowdhury O, Daley RA, Yazdankhah M, Gupta U, Hose SL, Valapala M, Fitting CS, Strizhakova A, Shan Y, Feenstra D, Sahel JA, Jayagopal A, Handa JT, Zigler JS, Fort PE, Sodhi A, Sinha D. Reducing Akt2 in retinal pigment epithelial cells causes a compensatory increase in Akt1 and attenuates diabetic retinopathy. Nat Commun 2022; 13:6045. [PMID: 36229454 PMCID: PMC9561713 DOI: 10.1038/s41467-022-33773-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 10/03/2022] [Indexed: 01/14/2023] Open
Abstract
The retinal pigment epithelium (RPE) plays an important role in the development of diabetic retinopathy (DR), a leading cause of blindness worldwide. Here we set out to explore the role of Akt2 signaling-integral to both RPE homeostasis and glucose metabolism-to DR. Using human tissue and genetically manipulated mice (including RPE-specific conditional knockout (cKO) and knock-in (KI) mice), we investigate whether Akts in the RPE influences DR in models of diabetic eye disease. We found that Akt1 and Akt2 activities were reciprocally regulated in the RPE of DR donor tissue and diabetic mice. Akt2 cKO attenuated diabetes-induced retinal abnormalities through a compensatory upregulation of phospho-Akt1 leading to an inhibition of vascular injury, inflammatory cytokine release, and infiltration of immune cells mediated by the GSK3β/NF-κB signaling pathway; overexpression of Akt2 has no effect. We propose that targeting Akt1 activity in the RPE may be a novel therapy for treating DR.
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Affiliation(s)
- Haitao Liu
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Nadezda A. Stepicheva
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Sayan Ghosh
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Peng Shang
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA ,grid.280881.b0000 0001 0097 5623Present Address: Doheny Eye Institute, Pasadena, CA USA
| | - Olivia Chowdhury
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Rachel A. Daley
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Meysam Yazdankhah
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA ,grid.443945.b0000 0004 0566 7998Present Address: Neural Stem Cell Institute, Rensselaer, NY USA
| | - Urvi Gupta
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Stacey L. Hose
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Mallika Valapala
- grid.411377.70000 0001 0790 959XSchool of Optometry, Indiana University, Bloomington, IN USA
| | - Christopher Scott Fitting
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Anastasia Strizhakova
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA
| | - Yang Shan
- grid.214458.e0000000086837370Kellogg Eye Center, University of Michigan School of Medicine, Ann Arbor, MI USA
| | - Derrick Feenstra
- grid.417570.00000 0004 0374 1269Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche, Ltd., Basel, Switzerland
| | - José-Alain Sahel
- grid.21925.3d0000 0004 1936 9000Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA USA ,grid.462844.80000 0001 2308 1657Institut de la Vision, INSERM, CNRS, Sorbonne Université, Paris, France
| | | | - James T. Handa
- grid.21107.350000 0001 2171 9311The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - J. Samuel Zigler
- grid.21107.350000 0001 2171 9311The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Patrice E. Fort
- grid.214458.e0000000086837370Kellogg Eye Center, University of Michigan School of Medicine, Ann Arbor, MI USA
| | - Akrit Sodhi
- grid.21107.350000 0001 2171 9311The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD USA
| | - Debasish Sinha
- Department of Ophthalmology, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. .,The Wilmer Eye Institute, The Johns Hopkins University School of Medicine, Baltimore, MD, USA.
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5
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Kikuchi Y, Sugano E, Yuki S, Tabata K, Endo Y, Takita Y, Onoguchi R, Ozaki T, Fukuda T, Takai Y, Kurose T, Tanaka K, Honma Y, Perez E, Stock M, Fernández JR, Tamura M, Voronkov M, Stock JB, Tomita H. SIG-1451, a Novel, Non-Steroidal Anti-Inflammatory Compound, Attenuates Light-Induced Photoreceptor Degeneration by Affecting the Inflammatory Process. Int J Mol Sci 2022; 23:ijms23158802. [PMID: 35955937 PMCID: PMC9369167 DOI: 10.3390/ijms23158802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 08/02/2022] [Accepted: 08/03/2022] [Indexed: 11/16/2022] Open
Abstract
Age-related macular degeneration is a progressive retinal disease that is associated with factors such as oxidative stress and inflammation. In this study, we evaluated the protective effects of SIG-1451, a non-steroidal anti-inflammatory compound developed for treating atopic dermatitis and known to inhibit Toll-like receptor 4, in light-induced photoreceptor degeneration. SIG-1451 was intraperitoneally injected into rats once per day before exposure to 1000 lx light for 24 h; one day later, optical coherence tomography showed a decrease in retinal thickness, and electroretinogram (ERG) amplitude was also found to have decreased 3 d after light exposure. Moreover, SIG-1451 partially protected against this decrease in retinal thickness and increase in ERG amplitude. One day after light exposure, upregulation of inflammatory response-related genes was observed, and SIG-1451 was found to inhibit this upregulation. Iba-1, a microglial marker, was suppressed in SIG-1451-injected rats. To investigate the molecular mechanism underlying these effects, we used lipopolysaccharide (LPS)-stimulated rat immortalised Müller cells. The upregulation of C-C motif chemokine 2 by LPS stimulation was significantly inhibited by SIG-1451 treatment, and Western blot analysis revealed a decrease in phosphorylated I-κB levels. These results indicate that SIG-1451 indirectly protects photoreceptor cells by attenuating light damage progression, by affecting the inflammatory responses.
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Affiliation(s)
- Yuki Kikuchi
- Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University Division of Science and Engineering, 4-3-5 Ueda, Morioka 020-8551, Iwate, Japan
| | - Eriko Sugano
- Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University Division of Science and Engineering, 4-3-5 Ueda, Morioka 020-8551, Iwate, Japan
| | - Shiori Yuki
- Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University Division of Science and Engineering, 4-3-5 Ueda, Morioka 020-8551, Iwate, Japan
| | - Kitako Tabata
- Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University Division of Science and Engineering, 4-3-5 Ueda, Morioka 020-8551, Iwate, Japan
| | - Yuka Endo
- Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University Division of Science and Engineering, 4-3-5 Ueda, Morioka 020-8551, Iwate, Japan
| | - Yuya Takita
- Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University Division of Science and Engineering, 4-3-5 Ueda, Morioka 020-8551, Iwate, Japan
| | - Reina Onoguchi
- Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University Division of Science and Engineering, 4-3-5 Ueda, Morioka 020-8551, Iwate, Japan
| | - Taku Ozaki
- Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University Division of Science and Engineering, 4-3-5 Ueda, Morioka 020-8551, Iwate, Japan
| | - Tomokazu Fukuda
- Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University Division of Science and Engineering, 4-3-5 Ueda, Morioka 020-8551, Iwate, Japan
| | - Yoshihiro Takai
- Rohto Pharmaceutical Co., Ltd., 6-5-4 Kunimidai, Kizugawa 619-0216, Kyoto, Japan
| | - Takahiro Kurose
- Rohto Pharmaceutical Co., Ltd., 6-5-4 Kunimidai, Kizugawa 619-0216, Kyoto, Japan
| | - Koichi Tanaka
- Rohto Pharmaceutical Co., Ltd., 6-5-4 Kunimidai, Kizugawa 619-0216, Kyoto, Japan
| | - Yoichi Honma
- Rohto Pharmaceutical Co., Ltd., 6-5-4 Kunimidai, Kizugawa 619-0216, Kyoto, Japan
| | - Eduardo Perez
- Signum Biosciences, 4999 Pearl East Circle, Boulder, CO 80301, USA
| | - Maxwell Stock
- Signum Biosciences, 4999 Pearl East Circle, Boulder, CO 80301, USA
| | | | - Masanori Tamura
- Signum Biosciences, 4999 Pearl East Circle, Boulder, CO 80301, USA
| | - Michael Voronkov
- Signum Biosciences, 4999 Pearl East Circle, Boulder, CO 80301, USA
| | - Jeffry B. Stock
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544-1014, USA
| | - Hiroshi Tomita
- Laboratory of Visual Neuroscience, Graduate Course in Biological Sciences, Iwate University Division of Science and Engineering, 4-3-5 Ueda, Morioka 020-8551, Iwate, Japan
- Correspondence: ; Tel.: +81-19-621-6427
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Rajala A, Rajala R, Teel K, Rajala RVS. Ribosomal targeting strategy and nuclear labeling to analyze photoreceptor phosphoinositide signatures. Biochim Biophys Acta Mol Cell Biol Lipids 2022; 1867:159161. [PMID: 35427794 PMCID: PMC10812878 DOI: 10.1016/j.bbalip.2022.159161] [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: 02/02/2022] [Revised: 04/03/2022] [Accepted: 04/08/2022] [Indexed: 10/18/2022]
Abstract
Reversible phosphorylation of phosphatidylinositol by phosphoinositide (PI) kinases and phosphatases generates seven distinct phosphoinositide phosphates, called phosphoinositides or PIPs. All seven PIPs are formed in the retina and photoreceptor cells. Around 50 genes in the mammalian genome encode PI kinases and PI phosphatases. There are no studies available on the distribution of these enzymes in the retina and photoreceptors. AIM To employ Ribosomal Targeting Strategy and Nuclear Labeling to Analyze Phosphoinositide Signatures in rod-photoreceptor cells. METHODS HA-tagging of ribosomal protein Rpl22 was induced with Cre-recombinase under the control of the rhodopsin promoter. Actively translating mRNAs associated with polyribosomes were isolated by immunoprecipitation with HA antibody, followed by RNA isolation and gene identification. We also isolated biotinylated-rod nuclei from NuTRAP mice under the control of the rhodopsin-Cre promoter and analyzed nuclear phosphoinositides. RESULTS Our results indicate that the expression of class I and class III PI 3-kinase, PI4K IIIβ, PI 5-kinase, PIKfyve, PI3-phosphatases, MTMR2, 4, 6, 7, 14, PI4-phosphatase, TMEM55A, PI 5-phosphatases, SYNJI, INPP5B, INPP5E, INPP5F, SKIP and other phosphatases with dual substrate specificity, PTPMT1, SCAM1, and FIG4 are highly enriched in rod photoreceptor cells compared with the retina and cone-like retina. Our analysis identified the presence of PI(4)P, PI(3,4)P2, PI(3,5)P2, and PI(4,5)P2 in the rod nuclei. CONCLUSIONS Our studies for the first time demonstrate the expression of PI kinases, PI phosphatases, and nuclear PIPs in rod photoreceptor cells. The NuTRAP mice may be useful not only for epigenetic and transcriptomic studies but also for in vivo cell-specific lipidomics research.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Dean McGee Eye Institute, Oklahoma City, OK 73014, USA
| | - Rahul Rajala
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73014, USA
| | - Kenneth Teel
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Dean McGee Eye Institute, Oklahoma City, OK 73014, USA
| | - Raju V S Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Dean McGee Eye Institute, Oklahoma City, OK 73014, USA.
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7
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Rajala A, Teel K, Bhat MA, Batushansky A, Griffin TM, Purcell L, Rajala RVS. Insulin-like growth factor 1 receptor mediates photoreceptor neuroprotection. Cell Death Dis 2022; 13:613. [PMID: 35840554 PMCID: PMC9287313 DOI: 10.1038/s41419-022-05074-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 07/04/2022] [Accepted: 07/06/2022] [Indexed: 01/21/2023]
Abstract
Insulin-like growth factor I (IGF-1) is a neurotrophic factor and is the ligand for insulin-like growth factor 1 receptor (IGF-1R). Reduced expression of IGF-1 has been reported to cause deafness, mental retardation, postnatal growth failure, and microcephaly. IGF-1R is expressed in the retina and photoreceptor neurons; however, its functional role is not known. Global IGF-1 KO mice have age-related vision loss. We determined that conditional deletion of IGF-1R in photoreceptors and pan-retinal cells produces age-related visual function loss and retinal degeneration. Retinal pigment epithelial cell-secreted IGF-1 may be a source for IGF-1R activation in the retina. Altered retinal, fatty acid, and phosphoinositide metabolism are observed in photoreceptor and retinal cells lacking IGF-1R. Our results suggest that the IGF-1R pathway is indispensable for photoreceptor survival, and activation of IGF-1R may be an essential element of photoreceptor and retinal neuroprotection.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Dean McGee Eye Institute, Oklahoma City, OK, 73104, USA
| | - Kenneth Teel
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Dean McGee Eye Institute, Oklahoma City, OK, 73104, USA
| | - Mohd A Bhat
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Dean McGee Eye Institute, Oklahoma City, OK, 73104, USA
| | | | | | - Lindsey Purcell
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA
- Dean McGee Eye Institute, Oklahoma City, OK, 73104, USA
| | - Raju V S Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
- Dean McGee Eye Institute, Oklahoma City, OK, 73104, USA.
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
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8
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Sobsey CA, Froehlich B, Batist G, Borchers CH. Immuno-MALDI-MS for Accurate Quantitation of Targeted Peptides from Volume-Restricted Samples. Methods Mol Biol 2022; 2515:203-225. [PMID: 35776354 DOI: 10.1007/978-1-0716-2409-8_13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The immuno-MALDI-MS method can be used to quantify low-abundance proteins from clinical samples that offer only a limited amount of material for analysis. An internal standard, in the form of a stable isotope-labeled peptide, is used to ensure reproducible and absolute quantitation. The protocol described here was optimized for the quantitation of AKT1 and AKT2, but we offer instructions on how to adapt the method to target other proteins. The described workflow is compatible with automation via a liquid handling robot for high-throughput applications.
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Affiliation(s)
- Constance A Sobsey
- Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, QC, Canada
- Division of Experimental Medicine, McGill University, Montreal, QC, Canada
| | - Bjoern Froehlich
- University of Victoria - Genome BC Proteomics Centre, Victoria, BC, Canada
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada
| | - Gerald Batist
- Division of Experimental Medicine, McGill University, Montreal, QC, Canada
- Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University, Montreal, QC, Canada
- Exactis Innovation, Montreal, QC, Canada
| | - Christoph H Borchers
- Segal Cancer Proteomics Centre, Lady Davis Institute, Jewish General Hospital, McGill University, Montreal, QC, Canada.
- Gerald Bronfman Department of Oncology, Jewish General Hospital, McGill University, Montreal, QC, Canada.
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9
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Lewandowski D, Sander CL, Tworak A, Gao F, Xu Q, Skowronska-Krawczyk D. Dynamic lipid turnover in photoreceptors and retinal pigment epithelium throughout life. Prog Retin Eye Res 2021; 89:101037. [PMID: 34971765 PMCID: PMC10361839 DOI: 10.1016/j.preteyeres.2021.101037] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 12/13/2021] [Accepted: 12/15/2021] [Indexed: 12/13/2022]
Abstract
The retinal pigment epithelium-photoreceptor interphase is renewed each day in a stunning display of cellular interdependence. While photoreceptors use photosensitive pigments to convert light into electrical signals, the RPE supports photoreceptors in their function by phagocytizing shed photoreceptor tips, regulating the blood retina barrier, and modulating inflammatory responses, as well as regenerating the 11-cis-retinal chromophore via the classical visual cycle. These processes involve multiple protein complexes, tightly regulated ligand-receptors interactions, and a plethora of lipids and protein-lipids interactions. The role of lipids in maintaining a healthy interplay between the RPE and photoreceptors has not been fully delineated. In recent years, novel technologies have resulted in major advancements in understanding several facets of this interplay, including the involvement of lipids in phagocytosis and phagolysosome function, nutrient recycling, and the metabolic dependence between the two cell types. In this review, we aim to integrate the complex role of lipids in photoreceptor and RPE function, emphasizing the dynamic exchange between the cells as well as discuss how these processes are affected in aging and retinal diseases.
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Affiliation(s)
- Dominik Lewandowski
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Christopher L Sander
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Aleksander Tworak
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Fangyuan Gao
- Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Qianlan Xu
- Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA
| | - Dorota Skowronska-Krawczyk
- Department of Physiology and Biophysics, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA; Department of Ophthalmology, Center for Translational Vision Research, School of Medicine, UC Irvine, Irvine, CA, USA.
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10
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Abstract
The outer retina is nourished from the choroid, a capillary bed just inside the sclera. O2, glucose, and other nutrients diffuse out of the choroid and then filter through a monolayer of retinal pigment epithelium (RPE) cells to fuel the retina. Recent studies of energy metabolism have revealed striking differences between retinas and RPE cells in the ways that they extract energy from fuels. The purpose of this review is to suggest and evaluate the hypothesis that the retina and RPE have complementary metabolic roles that make them depend on each other for survival and for their abilities to perform essential and specialized functions. Expected final online publication date for the Annual Review of Vision Science, Volume 7 is September 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
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Affiliation(s)
- James B Hurley
- Departments of Biochemistry and Ophthalmology, University of Washington, Seattle, Washington 98115, USA;
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11
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Rajala RVS, McCauley A, Rajala R, Teel K, Rajala A. Regulation of Phosphoinositide Levels in the Retina by Protein Tyrosine Phosphatase 1B and Growth Factor Receptor-Bound Protein 14. Biomolecules 2021; 11:biom11040602. [PMID: 33921658 PMCID: PMC8073254 DOI: 10.3390/biom11040602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Revised: 04/09/2021] [Accepted: 04/15/2021] [Indexed: 11/16/2022] Open
Abstract
Protein tyrosine kinases and protein phosphatases play a critical role in cellular regulation. The length of a cellular response depends on the interplay between activating protein kinases and deactivating protein phosphatases. Protein tyrosine phosphatase 1B (PTP1B) and growth factor receptor-bound protein 14 (Grb14) are negative regulators of receptor tyrosine kinases. However, in the retina, we have previously shown that PTP1B inactivates insulin receptor signaling, whereas phosphorylated Grb14 inhibits PTP1B activity. In silico docking of phosphorylated Grb14 and PTP1B indicate critical residues in PTP1B that may mediate the interaction. Phosphoinositides (PIPs) are acidic lipids and minor constituents in the cell that play an important role in cellular processes. Their levels are regulated by growth factor signaling. Using phosphoinositide binding protein probes, we observed increased levels of PI(3)P, PI(4)P, PI(3,4)P2, PI(4,5)P2, and PI(3,4,5)P3 in PTP1B knockout mouse retina and decreased levels of these PIPs in Grb14 knockout mouse retina. These observations suggest that the interplay between PTP1B and Grb14 can regulate PIP metabolism.
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Affiliation(s)
- Raju V. S. Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (A.M.); (K.T.); (A.R.)
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA;
- Dean McGee Eye Institute, Oklahoma City, OK 73104, USA
- Correspondence: ; Tel.: +1-405-271-8255; Fax: +1-405-271-8128
| | - Austin McCauley
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (A.M.); (K.T.); (A.R.)
- Dean McGee Eye Institute, Oklahoma City, OK 73104, USA
| | - Rahul Rajala
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA;
- Cardiovascular Biology Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA
| | - Kenneth Teel
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (A.M.); (K.T.); (A.R.)
- Dean McGee Eye Institute, Oklahoma City, OK 73104, USA
| | - Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; (A.M.); (K.T.); (A.R.)
- Dean McGee Eye Institute, Oklahoma City, OK 73104, USA
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12
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Abstract
The field of phosphoinositide signaling has expanded significantly in recent years. Phosphoinositides (also known as phosphatidylinositol phosphates or PIPs) are universal signaling molecules that directly interact with membrane proteins or with cytosolic proteins containing domains that directly bind phosphoinositides and are recruited to cell membranes. Through the activities of phosphoinositide kinases and phosphoinositide phosphatases, seven distinct phosphoinositide lipid molecules are formed from the parent molecule, phosphatidylinositol. PIP signals regulate a wide range of cellular functions, including cytoskeletal assembly, membrane budding and fusion, ciliogenesis, vesicular transport, and signal transduction. Given the many excellent reviews on phosphoinositide kinases, phosphoinositide phosphatases, and PIPs in general, in this review, we discuss recent studies and advances in PIP lipid signaling in the retina. We specifically focus on PIP lipids from vertebrate (e.g., bovine, rat, mouse, toad, and zebrafish) and invertebrate (e.g., Drosophila, horseshoe crab, and squid) retinas. We also discuss the importance of PIPs revealed from animal models and human diseases, and methods to study PIP levels both in vitro and in vivo. We propose that future studies should investigate the function and mechanism of activation of PIP-modifying enzymes/phosphatases and further unravel PIP regulation and function in the different cell types of the retina.
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Affiliation(s)
- Raju V S Rajala
- Departments of Ophthalmology, Physiology, and Cell Biology, and Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104.
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13
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Kokona D, Spyridakos D, Tzatzarakis M, Papadogkonaki S, Filidou E, Arvanitidis KI, Kolios G, Lamani M, Makriyannis A, Malamas MS, Thermos K. The endocannabinoid 2-arachidonoylglycerol and dual ABHD6/MAGL enzyme inhibitors display neuroprotective and anti-inflammatory actions in the in vivo retinal model of AMPA excitotoxicity. Neuropharmacology 2021; 185:108450. [PMID: 33450278 DOI: 10.1016/j.neuropharm.2021.108450] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 12/17/2020] [Accepted: 01/03/2021] [Indexed: 12/14/2022]
Abstract
The endocannabinoid system has been shown to be a putative therapeutic target for retinal disease. Here, we aimed to investigate the ability of the endocannabinoid 2-arachidonoylglycerol (2-AG) and novel inhibitors of its metabolic enzymes, α/β-hydrolase domain-containing 6 (ABHD6) and monoacylglycerol lipase (MAGL), a) to protect the retina against excitotoxicity and b) the mechanisms involved in the neuroprotection. Sprague-Dawley rats, wild type and Akt2-/- C57BL/6 mice were intravitreally administered with phosphate-buffered saline or (RS)-α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid hydrobromide (AMPA). 2-AG was intravitreally co-administered with AMPA in the absence and presence of AM251 or AM630 (cannabinoid 1 and 2 receptor antagonists, respectively) or Wortmannin [Phosphoinositide 3-Kinase (PI3K)/Akt inhibitor]. Inhibitors of ABHD6 and dual ABHD6/MAGL (AM12100 and AM11920, respectively) were co-administered with AMPA intravitreally in rats. Immunohistochemistry was performed using antibodies raised against retinal neuronal markers (bNOS), microglia (Iba1) and macroglia (GFAP). TUNEL assay and real-time PCR were also employed. The CB2 receptor was expressed in rat retina (approx. 62% of CB1 expression). 2-AG attenuated the AMPA-induced increase in TUNEL+ cells. 2-AG activation of both CB1 and CB2 receptors and the PI3K/Akt downstream signaling pathway, as substantiated by the use of Akt2-/- mice, afforded neuroprotection against AMPA excitotoxicity. AM12100 and AM11920 attenuated the AMPA-induced glia activation and produced a dose-dependent partial neuroprotection, with the dual inhibitor AM11920 being more efficacious. These results show that 2-AG has the pharmacological profile of a putative therapeutic for retinal diseases characterized by neurodegeneration and neuroinflammation, when administered exogenously or by the inhibition of its metabolic enzymes.
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Affiliation(s)
- Despina Kokona
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Crete, 71003, Greece.
| | - Dimitris Spyridakos
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Crete, 71003, Greece.
| | - Manolis Tzatzarakis
- Department of Toxicology, School of Medicine, University of Crete, Heraklion, Crete, 71003, Greece.
| | - Sofia Papadogkonaki
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Crete, 71003, Greece.
| | - Eirini Filidou
- Laboratory of Pharmacology, School of Medicine, Democritus University of Thrace, Alexandroupolis, 68100, Greece.
| | - Konstantinos I Arvanitidis
- Laboratory of Pharmacology, School of Medicine, Democritus University of Thrace, Alexandroupolis, 68100, Greece.
| | - George Kolios
- Laboratory of Pharmacology, School of Medicine, Democritus University of Thrace, Alexandroupolis, 68100, Greece.
| | - Manjunath Lamani
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA.
| | - Alexandros Makriyannis
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA.
| | - Michael S Malamas
- Center for Drug Discovery and Departments of Chemistry and Chemical Biology and Pharmaceutical Sciences, Northeastern University, Boston, MA, 02115, USA.
| | - Kyriaki Thermos
- Department of Pharmacology, School of Medicine, University of Crete, Heraklion, Crete, 71003, Greece.
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14
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Sheet S, Krishnamoorthy S, Park W, Lim D, Park JE, Ko M, Choi BH. Mechanistic insight into the progressive retinal atrophy disease in dogs via pathway-based genome-wide association analysis. JOURNAL OF ANIMAL SCIENCE AND TECHNOLOGY 2020; 62:765-776. [PMID: 33987558 PMCID: PMC7721568 DOI: 10.5187/jast.2020.62.6.765] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/25/2020] [Accepted: 09/06/2020] [Indexed: 01/01/2023]
Abstract
The retinal degenerative disease, progressive retinal atrophy (PRA) is a major
reason of vision impairment in canine population. Canine PRA signifies an
inherently dissimilar category of retinal dystrophies which has solid
resemblances to human retinis pigmentosa. Even though much is known about the
biology of PRA, the knowledge about the intricate connection among genetic loci,
genes and pathways associated to this disease in dogs are still remain unknown.
Therefore, we have performed a genome wide association study (GWAS) to identify
susceptibility single nucleotide polymorphisms (SNPs) of PRA. The GWAS was
performed using a case–control based association analysis method on PRA
dataset of 129 dogs and 135,553 markers. Further, the gene-set and pathway
analysis were conducted in this study. A total of 1,114 markers associations
with PRA trait at p < 0.01 were extracted and mapped to
640 unique genes, and then selected significant (p <
0.05) enriched 35 gene ontology (GO) terms and 5 Kyoto Encyclopedia of Genes and
Genomes (KEGG) pathways contain these genes. In particular, apoptosis process,
homophilic cell adhesion, calcium ion binding, and endoplasmic reticulum GO
terms as well as pathways related to focal adhesion, cyclic guanosine
monophosphate)-protein kinase G signaling, and axon guidance were more likely
associated to the PRA disease in dogs. These data could provide new insight for
further research on identification of potential genes and causative pathways for
PRA in dogs.
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Affiliation(s)
- Sunirmal Sheet
- Animal Genomics and Bioinformatics Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Korea
| | - Srikanth Krishnamoorthy
- Animal Genomics and Bioinformatics Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Korea
| | - Woncheoul Park
- Animal Genomics and Bioinformatics Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Korea
| | - Dajeong Lim
- Animal Genomics and Bioinformatics Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Korea
| | - Jong-Eun Park
- Animal Genomics and Bioinformatics Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Korea
| | - Minjeong Ko
- Animal Genomics and Bioinformatics Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Korea
| | - Bong-Hwan Choi
- Animal Genomics and Bioinformatics Division, National Institute of Animal Science, Rural Development Administration, Wanju 55365, Korea
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15
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Haydinger CD, Kittipassorn T, Peet DJ. Power to see-Drivers of aerobic glycolysis in the mammalian retina: A review. Clin Exp Ophthalmol 2020; 48:1057-1071. [PMID: 32710505 DOI: 10.1111/ceo.13833] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/03/2020] [Accepted: 07/20/2020] [Indexed: 12/17/2022]
Abstract
The mammalian retina converts most glucose to lactate rather than catabolizing it completely to carbon dioxide via oxidative phosphorylation, despite the availability of oxygen. This unusual metabolism is known as aerobic glycolysis or the Warburg effect. Molecules and pathways that drive aerobic glycolysis have been identified and thoroughly studied in the context of cancer but remain relatively poorly understood in the retina. Here, we review recent research on the molecular mechanisms that underly aerobic glycolysis in the retina, focusing on key glycolytic enzymes including hexokinase 2 (HK2), pyruvate kinase M2 (PKM2) and lactate dehydrogenase A (LDHA). We also discuss the potential involvement of cell signalling and transcriptional pathways including phosphoinositide 3-kinase (PI3K) signalling, fibroblast growth factor receptor (FGFR) signalling, and hypoxia-inducible factor 1 (HIF-1), which have been implicated in driving aerobic glycolysis in the context of cancer.
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Affiliation(s)
- Cameron D Haydinger
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
| | - Thaksaon Kittipassorn
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia.,Department of Physiology, Faculty of Medicine Siriraj Hospital, Mahidol University, Mahidol, Thailand
| | - Daniel J Peet
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
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16
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Marmoy OR, Kinsler VA, Henderson RH, Handley SE, Moore W, Thompson DA. Misaligned foveal morphology and sector retinal dysfunction in AKT1-mosaic Proteus syndrome. Doc Ophthalmol 2020; 142:119-126. [PMID: 32617723 DOI: 10.1007/s10633-020-09778-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2020] [Accepted: 06/11/2020] [Indexed: 11/29/2022]
Abstract
PURPOSE Proteus syndrome arises as a result of a post-zygotic mosaic activating mutation in the AKT1 oncogene, causing a disproportionate overgrowth of affected tissues. A small number of ocular complications have been reported. We present the unique findings in a patient who had molecular confirmation of AKT1 mosaicism alongside fulfilling the clinical criteria for Proteus syndrome. METHODS Pattern electroretinography, visual evoked potentials and multifocal electroretinography testing were performed alongside detailed retinal imaging and clinical examination to detail the ophthalmic characteristics. RESULTS Electrophysiological findings characterised unilateral macular dysfunction alongside sector retinal dysfunction of the right eye. This was demonstrated through optical coherence tomography and ultra-wide-field imaging to be associated with a misaligned foveal morphology and sector retinal dysfunction extending into the temporal retina. CONCLUSION We propose this patient has asymmetric foveal development and concomitant sector retinal dysfunction as the result of the mosaic AKT1 mutation, either through disruption in the retinal PI3K-AKT1 signalling pathway or through mechanical distortion of ocular growth, resulting in disproportionate inner retinal development. The findings expand the ocular phenotype of Proteus syndrome and encourage early assessment to identify any incipient ocular abnormalities.
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Affiliation(s)
- Oliver R Marmoy
- Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children, London, UK. .,Manchester Metropolitan University, Manchester, UK.
| | - Veronica A Kinsler
- Paediatric Dermatology, Great Ormond Street Hospital for Children, London, UK.,UCL-GOSH Institute of Child Health, University College London, London, UK
| | - Robert H Henderson
- Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children, London, UK.,UCL-GOSH Institute of Child Health, University College London, London, UK
| | - Sian E Handley
- Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children, London, UK.,UCL-GOSH Institute of Child Health, University College London, London, UK
| | - Will Moore
- Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children, London, UK
| | - Dorothy A Thompson
- Clinical and Academic Department of Ophthalmology, Great Ormond Street Hospital for Children, London, UK.,UCL-GOSH Institute of Child Health, University College London, London, UK
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17
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Weh E, Lutrzykowska Z, Smith A, Hager H, Pawar M, Wubben TJ, Besirli CG. Hexokinase 2 is dispensable for photoreceptor development but is required for survival during aging and outer retinal stress. Cell Death Dis 2020; 11:422. [PMID: 32499533 PMCID: PMC7272456 DOI: 10.1038/s41419-020-2638-2] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 05/15/2020] [Accepted: 05/18/2020] [Indexed: 02/06/2023]
Abstract
Photoreceptor death is the ultimate cause of vision loss in many retinal degenerative conditions. Identifying novel therapeutic avenues for prolonging photoreceptor health and function has the potential to improve vision and quality of life for patients suffering from degenerative retinal disorders. Photoreceptors are metabolically unique among other neurons in that they process the majority of their glucose via aerobic glycolysis. One of the main regulators of aerobic glycolysis is hexokinase 2 (HK2). Beyond its enzymatic function of phosphorylating glucose to glucose-6-phosphate, HK2 has additional non-enzymatic roles, including the regulation of apoptotic signaling via AKT signaling. Determining the role of HK2 in photoreceptor homeostasis may identify novel signaling pathways that can be targeted with neuroprotective agents to boost photoreceptor survival during metabolic stress. Here we show that following experimental retinal detachment, p-AKT is upregulated and HK2 translocates to mitochondria. Inhibition of AKT phosphorylation in 661W photoreceptor-like cells results in translocation of mitochondrial HK2 to the cytoplasm, increased caspase activity, and decreased cell viability. Rod-photoreceptors lacking HK2 upregulate HK1 and appear to develop normally. Interestingly, we found that HK2-deficient photoreceptors are more susceptible to acute nutrient deprivation in the experimental retinal detachment model. Additionally, HK2 appears to be important for preserving photoreceptors during aging. We show that retinal glucose metabolism is largely unchanged after HK2 deletion, suggesting that the non-enzymatic role of HK2 is important for maintaining photoreceptor health. These results suggest that HK2 expression is critical for preserving photoreceptors during acute nutrient stress and aging. More specifically, p-AKT mediated translocation of HK2 to the mitochondrial surface may be critical for protecting photoreceptors from acute and chronic stress.
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Affiliation(s)
- Eric Weh
- Department of Ophthalmology and Visual Sciences, University of Michigan, 1000 Wall St., Ann Arbor, MI, 48105, US
| | | | - Andrew Smith
- Department of Ophthalmology and Visual Sciences, University of Michigan, 1000 Wall St., Ann Arbor, MI, 48105, US
| | - Heather Hager
- Department of Ophthalmology and Visual Sciences, University of Michigan, 1000 Wall St., Ann Arbor, MI, 48105, US
| | - Mercy Pawar
- Department of Ophthalmology and Visual Sciences, University of Michigan, 1000 Wall St., Ann Arbor, MI, 48105, US
| | - Thomas J Wubben
- Department of Ophthalmology and Visual Sciences, University of Michigan, 1000 Wall St., Ann Arbor, MI, 48105, US
| | - Cagri G Besirli
- Department of Ophthalmology and Visual Sciences, University of Michigan, 1000 Wall St., Ann Arbor, MI, 48105, US.
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18
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Rajala A, Soni K, Rajala RVS. Metabolic and Non-metabolic Roles of Pyruvate Kinase M2 Isoform in Diabetic Retinopathy. Sci Rep 2020; 10:7456. [PMID: 32366925 PMCID: PMC7198623 DOI: 10.1038/s41598-020-64487-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Accepted: 04/17/2020] [Indexed: 12/25/2022] Open
Abstract
The main therapeutic goal for diabetic retinopathy (DR) is to prevent vision loss in patients with diabetes mellitus. Identifying the visual complications at a preclinical juncture will offer an early therapeutic window for diagnosis and intervention. Very recently, we found that pyruvate kinase M2 isoform (PKM2) regulates visual function through regulation of a key enzyme, phosphodiesterase 6β (Pde6β), involved in modulating photoreceptor functions. A recent study showed that the activation of PKM2 protects mitochondrial integrity in diabetic nephropathy. In the present study, we examined the role of PKM2 in DR in a mouse model that has both phenotypes of obesity and type II diabetes. In DR, we found decreased expression of PKM2 and Pde6β expression, but not PKM1. Consistent with decreased Pde6β expression, the db/db mice had reduced rod photoreceptor function. We found increased pyruvate kinase activity and a decreased ratio of reduced/oxidized redox in db/db mouse retina compared with control retinas. There was no significant difference in the levels of lactate between db/db and control mouse retina. Our findings suggest that reduced expression of PKM2 with unchanged PKM1 expression might be responsible for higher pyruvate kinase activity in db/db mouse retina. Our studies suggest that PKM2 has a role in DR. The results support that PKM2 may serve as a therapeutic target in the treatment of DR.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma, 73104, USA.,Dean McGee Eye Institute, Oklahoma City, USA
| | - Krutik Soni
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma, 73104, USA.,Dean McGee Eye Institute, Oklahoma City, USA
| | - Raju V S Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma, 73104, USA. .,Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma, 73104, USA. .,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma, 73104, USA. .,Dean McGee Eye Institute, Oklahoma City, USA.
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19
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Collin GB, Gogna N, Chang B, Damkham N, Pinkney J, Hyde LF, Stone L, Naggert JK, Nishina PM, Krebs MP. Mouse Models of Inherited Retinal Degeneration with Photoreceptor Cell Loss. Cells 2020; 9:cells9040931. [PMID: 32290105 PMCID: PMC7227028 DOI: 10.3390/cells9040931] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2020] [Revised: 04/05/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022] Open
Abstract
Inherited retinal degeneration (RD) leads to the impairment or loss of vision in millions of individuals worldwide, most frequently due to the loss of photoreceptor (PR) cells. Animal models, particularly the laboratory mouse, have been used to understand the pathogenic mechanisms that underlie PR cell loss and to explore therapies that may prevent, delay, or reverse RD. Here, we reviewed entries in the Mouse Genome Informatics and PubMed databases to compile a comprehensive list of monogenic mouse models in which PR cell loss is demonstrated. The progression of PR cell loss with postnatal age was documented in mutant alleles of genes grouped by biological function. As anticipated, a wide range in the onset and rate of cell loss was observed among the reported models. The analysis underscored relationships between RD genes and ciliary function, transcription-coupled DNA damage repair, and cellular chloride homeostasis. Comparing the mouse gene list to human RD genes identified in the RetNet database revealed that mouse models are available for 40% of the known human diseases, suggesting opportunities for future research. This work may provide insight into the molecular players and pathways through which PR degenerative disease occurs and may be useful for planning translational studies.
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Affiliation(s)
- Gayle B. Collin
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Navdeep Gogna
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Bo Chang
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Nattaya Damkham
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Department of Immunology, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
- Siriraj Center of Excellence for Stem Cell Research, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkok 10700, Thailand
| | - Jai Pinkney
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lillian F. Hyde
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Lisa Stone
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Jürgen K. Naggert
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
| | - Patsy M. Nishina
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
| | - Mark P. Krebs
- The Jackson Laboratory, Bar Harbor, Maine, ME 04609, USA; (G.B.C.); (N.G.); (B.C.); (N.D.); (J.P.); (L.F.H.); (L.S.); (J.K.N.)
- Correspondence: (P.M.N.); (M.P.K.); Tel.: +1-207-2886-383 (P.M.N.); +1-207-2886-000 (M.P.K.)
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Rajala A, Rajala RVS. A non-canonical rhodopsin-mediated insulin receptor signaling pathway in retinal photoreceptor neurons. Cell Biol Int 2020; 44:1020-1027. [PMID: 31889373 DOI: 10.1002/cbin.11299] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Accepted: 12/28/2019] [Indexed: 01/08/2023]
Abstract
We previously reported a ligand-independent and rhodopsin-dependent insulin receptor (IR) neuroprotective signaling pathway in both rod and cone photoreceptor cells, which is activated through protein-protein interaction. Our previous studies were performed with either retina or isolated rod or cone outer segment preparations and the expression of IR signaling proteins were examined. The isolation of outer segments with large portions of the attached inner segments is a technical challenge. Optiprep™ density gradient medium has been used to isolate the cells and subcellular organelles, Optiprep™ is a non-ionic iodixanol-based medium with a density of 1.320 g/mL. We employed this method to examine the expression of IR and its signaling proteins, and activation of one of the downstream effectors of the IR in isolated photoreceptor cells. Identification of the signaling complexes will be helpful for therapeutic targeting in disease conditions.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma, OK, 73104, USA.,Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma City, OK, 73104, USA
| | - Raju V S Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma, OK, 73104, USA.,Department of Physiology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma, OK, 73104, USA.,Department of Cell Biology, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma, OK, 73104, USA.,Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, 608 Stanton L. Young Blvd, Oklahoma City, OK, 73104, USA
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N-Methyl- N-Nitrosourea-Induced Photoreceptor Degeneration Is Inhibited by Nicotinamide via the Blockade of Upstream Events before the Phosphorylation of Signalling Proteins. BIOMED RESEARCH INTERNATIONAL 2019; 2019:3238719. [PMID: 31179317 PMCID: PMC6507250 DOI: 10.1155/2019/3238719] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 04/09/2019] [Accepted: 04/15/2019] [Indexed: 01/12/2023]
Abstract
N-methyl-N-nitrosourea (MNU), a known carcinogen, is generally used in animal models to chemically induce photoreceptor degeneration. It has been reported that nicotinamide (NAM) exerts a protective effect on MNU-induced photoreceptor degeneration. We investigated the molecular mechanisms on MNU-induced photoreceptor degeneration. Intraperitoneal MNU injection (75 mg/kg) in rats induced selective photoreceptor degeneration in 7 days. NAM administration completely inhibited photoreceptor degeneration. Photoreceptor layer abnormality was observed within 6 hours after MNU injection, whereas it was restored in the NAM-treated retina, as detected by optical coherence tomography. One day following MNU administration, phosphorylation of the cell death-associated signalling proteins c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (p38) increased, while the apoptosis-related proteins, full-length poly(ADP-ribose) polymerase (PARP) and apoptosis-inducing factor (AIF), were depleted. These changes were not observed in the NAM-treated retinas. Cell survival signalling, such as extracellular signal-regulated kinase (ERK), Akt, and cAMP response element binding protein (CREB) phosphorylation, increased in the MNU- but not in the NAM-treated rat retinas. Increased phosphorylated ERK (p-ERK) levels were observed within 6 hours after MNU administration, suggestive of cell survival signalling activation. This did not occur in NAM-treated retinas. These results indicate that NAM regulates upstream cellular events prior to the activation of cell death-related signalling events, such as JNK and p38 phosphorylation.
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Matsuda S, Ikeda Y, Murakami M, Nakagawa Y, Tsuji A, Kitagishi Y. Roles of PI3K/AKT/GSK3 Pathway Involved in Psychiatric Illnesses. Diseases 2019; 7:diseases7010022. [PMID: 30781836 PMCID: PMC6473240 DOI: 10.3390/diseases7010022] [Citation(s) in RCA: 93] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Revised: 02/10/2019] [Accepted: 02/11/2019] [Indexed: 12/31/2022] Open
Abstract
Psychiatric illnesses may be qualified to the cellular impairments of the function for survival or death in neurons, which may consequently appear as abnormalities in the neuroplasticity. The molecular mechanism has not been well understood, however, it seems that PI3K, AKT, GSK3, and their downstream molecules have crucial roles in the pathogenesis. Through transducing cell surviving signal, the PI3K/AKT/GSK3 pathway may organize an intracellular central network for the action of the synaptic neuroplasticity. In addition, the pathways may also regulate cell proliferation, cell migration, and apoptosis. Several lines of evidence have supported a role for this signaling network underlying the development and treatment for psychiatric illnesses. Indeed, the discovery of molecular biochemical phenotypes would represent a breakthrough in the research for effective treatment. In this review, we summarize advances on the involvement of the PI3K/AKT/GSK3 pathways in cell signaling of neuronal cells. This study may provide novel insights on the mechanism of mental disorder involved in psychiatric illnesses and would open future opportunity for contributions suggesting new targets for diagnostic and/or therapeutic procedures.
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Affiliation(s)
- Satoru Matsuda
- Department of Food Science and Nutrition, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan.
| | - Yuka Ikeda
- Department of Food Science and Nutrition, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan.
| | - Mutsumi Murakami
- Department of Food Science and Nutrition, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan.
| | - Yukie Nakagawa
- Department of Food Science and Nutrition, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan.
| | - Ai Tsuji
- Department of Food Science and Nutrition, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan.
| | - Yasuko Kitagishi
- Department of Food Science and Nutrition, Nara Women's University, Kita-Uoya Nishimachi, Nara 630-8506, Japan.
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Deng Z, Yuan C, Yang J, Peng Y, Wang W, Wang Y, Gao W. Behavioral defects induced by chronic social defeat stress are protected by Momordica charantia polysaccharides via attenuation of JNK3/PI3K/AKT neuroinflammatory pathway. ANNALS OF TRANSLATIONAL MEDICINE 2019; 7:6. [PMID: 30788353 DOI: 10.21037/atm.2018.12.08] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Background The aim of this study was to evaluate the protective effects of Momordica charantia polysaccharides (MCP) on depressive-like behaviors. Methods The chronic social defeat stress (CSDS) mice model was used to evaluate the effects of MCP and their underlying mechanisms. Social interaction test (SIT), sucrose preference test (SPT), and tail suspension test (TST) were performed for behavioral assessments. Expression levels of inflammation mediators and phosphatidylinositol 3-kinase (PI3K) activity were determined using commercial ELISA kits. The expression of key proteins in the c-Jun N-terminal protein kinase (JNK3)/PI3K/protein kinase B (AKT) pathway were measured using western blot and RT-PCR. Results The results showed that chronic administration of MCP (100, 200, 400 mg/kg/day) significantly prevented depressive-like behaviors in CSDS mice as assessed by SIT, TST and SPT. Elevated levels of proinflammatory cytokines [tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and interleukin-1 beta (IL-1β)], and expression of JNK3, c-Jun, P-110β proteins were observed in the hippocampus of CSDS mice. Moreover, the activity of PI3K and phosphorylation level of AKT were reduced in the hippocampus of CSDS mice. Interestingly, the administration of MCP reversed these changes. Furthermore, the protective effects of MCP on CSDS mice were partly inhibited by the PI3K inhibitor, LY294002. Conclusions In conclusion, the protective effects of MCP against depressive-like behaviors in CSDS mice might be due to a reduction in neuroinflammation and the down-regulation of the JNK3/PI3K/AKT pathway in the hippocampus.
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Affiliation(s)
- Zhifang Deng
- Department of Pharmacy, The First College of Clinical Medical Science, China Three Gorges University & Yichang Central People's Hospital, Yichang 443000, China
| | - Cheng Yuan
- Department of Radiation and Medical Oncology, Zhongnan Hospital, Wuhan University, Wuhan 430071, China
| | - Jian Yang
- Department of Central Experimental Laboratory, The First College of Clinical Medical Science, China Three Gorges University & Yichang Central People's Hospital, Yichang 443000, China
| | - Yan Peng
- Department of Pharmacy, The First College of Clinical Medical Science, China Three Gorges University & Yichang Central People's Hospital, Yichang 443000, China
| | - Wei Wang
- Department of Central Experimental Laboratory, The First College of Clinical Medical Science, China Three Gorges University & Yichang Central People's Hospital, Yichang 443000, China
| | - Yan Wang
- Department of Pharmacy, The First College of Clinical Medical Science, China Three Gorges University & Yichang Central People's Hospital, Yichang 443000, China
| | - Wenqi Gao
- Department of Central Experimental Laboratory, The First College of Clinical Medical Science, China Three Gorges University & Yichang Central People's Hospital, Yichang 443000, China
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Rajala RVS. Therapeutic Benefits from Nanoparticles: The Potential Significance of Nanoscience in Retinal Degenerative Diseases. JOURNAL OF MOLECULAR BIOLOGY & THERAPEUTICS 2019; 1:44-55. [PMID: 34528026 PMCID: PMC8439377] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Several nanotechnology podiums have gained remarkable attention in the area of medical sciences, including diagnostics and treatment. In the past decade, engineered multifunctional nanoparticles have served as drug and gene carriers. The most important aspect of translating nanoparticles from the bench to bedside is safety. These nanoparticles should not elicit any immune response and should not be toxic to humans or the environment. Lipid-based nanoparticles have been shown to be the least toxic for in vivo applications, and significant progress has been made in gene and drug delivery employing lipid-based nanoassemblies. Several excellent reviews and reports discuss the general use and application of lipid-based nanoparticles; our review focuses on the application of lipid-based nanoparticles for the treatment of ocular diseases, and recent advances in and updates on their use.
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Affiliation(s)
- Raju V S Rajala
- Departments of Ophthalmology, Physiology and Cell Biology, University of Oklahoma Health Sciences Center, Dean McGee Eye Institute, Oklahoma City, OK 73104, USA
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Rajala A, Wang Y, Soni K, Rajala RVS. Pyruvate kinase M2 isoform deletion in cone photoreceptors results in age-related cone degeneration. Cell Death Dis 2018; 9:737. [PMID: 29970877 PMCID: PMC6030055 DOI: 10.1038/s41419-018-0712-9] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 05/13/2018] [Accepted: 05/16/2018] [Indexed: 12/11/2022]
Abstract
The tumor form of pyruvate kinase M2 has been suggested to promote cellular anabolism by redirecting the metabolism to cause accumulation of glycolytic intermediates and increasing flux through the pentose phosphate pathway, which is a metabolic pathway parallel to glycolysis. Both rod and cone photoreceptors express the tumor form of pyruvate kinase M2. Recent studies from our laboratory show that PKM2 is functionally important for rod photoreceptor structure, function, and viability. However, the functional role of PKM2 in cones is not known. In this study, we conditionally deleted PKM2 in cones (cone-cre PKM2-KO) and found that loss of PKM2 results in the upregulation of PKM1 and a significant loss of cone function and cone degeneration in an age-dependent manner. Gene expression studies on cone-cre PKM2-KO show decreased expression of genes regulating glycolysis, PPP shunt, and fatty acid biosynthesis. Consistent with these observations, cones lacking PKM2 have significantly shorter cone outer segments than cones with PKM2. Our studies clearly suggest that PKM2 is essential for the anabolic process in cones to keep them alive for normal functioning and to support cone structure.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Dean McGee Eye Institute, Oklahoma City, OK, USA
| | - Yuhong Wang
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Dean McGee Eye Institute, Oklahoma City, OK, USA
| | - Krutik Soni
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.,Dean McGee Eye Institute, Oklahoma City, OK, USA
| | - Raju V S Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. .,Dean McGee Eye Institute, Oklahoma City, OK, USA. .,Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA. .,Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA.
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Redundant and Nonredundant Functions of Akt Isoforms in the Retina. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2018. [PMID: 29721991 DOI: 10.1007/978-3-319-75402-4_71] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2023]
Abstract
Serine/threonine kinase Akt is a downstream effector of the phosphoinositide 3-kinase pathway that is involved in many processes, including providing neuroprotection to stressed photoreceptor cells. Akt exists in three isoforms designated as Akt1, Akt2, and Akt3. All of these isoforms are expressed in the retina. We previously reported that Akt2 knockout mice were susceptible to light stress-induced photoreceptor degeneration, whereas Akt1 deletion had no effect on the retina. We hypothesized that the phenotype of Akt2 knockout mice may be due to the inactivation of specific substrate(s) in the retina. Yeast two-hybrid screening of a bovine retinal cDNA library with Akt2 identified a multidomain protein, POSH (plenty of SH3s), that acts as a scaffold for the JNK pathway of neuronal death. Our results suggest a stable interaction between Akt2 and POSH. Previous studies show that overexpression of POSH leads to cell death. The cell death that we observed in Akt2 knockout mice could be due to the absence of inactivation of POSH-mediated JNK signaling in the retina.
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Pyruvate kinase M2 regulates photoreceptor structure, function, and viability. Cell Death Dis 2018; 9:240. [PMID: 29445082 PMCID: PMC5833680 DOI: 10.1038/s41419-018-0296-4] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Revised: 12/18/2017] [Accepted: 12/27/2017] [Indexed: 01/30/2023]
Abstract
Pyruvate kinase M2 (PKM2) is a glycolytic enzyme that is expressed in cancer cells. Its role in tumor metabolism is not definitively established, but investigators have suggested that regulation of PKM2 activity can cause accumulation of glycolytic intermediates and increase flux through the pentose phosphate pathway. Recent evidence suggests that PKM2 also may have non-metabolic functions, including as a transcriptional co-activator in gene regulation. We reported previously that PKM2 is abundant in photoreceptor cells in mouse retinas. In the present study, we conditionally deleted PKM2 (rod-cre PKM2-KO) in rod photoreceptors and found that the absence of PKM2 causes increased expression of PKM1 in rods. Analysis of metabolic flux from U-13C glucose shows that rod-cre PKM2-KO retinas accumulate glycolytic intermediates, consistent with an overall reduction in the amount of pyruvate kinase activity. Rod-cre PKM2-KO mice also have an increased NADPH availability could favor lipid synthesis, but we found no difference in phospholipid synthesis between rod-cre PKM2 KO and PKM2-positive controls. As rod-cre PKM2-KO mice aged, we observed a significant loss of rod function, reduced thickness of the photoreceptor outer segment layer, and reduced expression of photoreceptor proteins, including PDE6β. The rod-cre PKM2-KO retinas showed greater TUNEL staining than wild-type retinas, indicating a slow retinal degeneration. In vitro analysis showed that PKM2 can regulate transcriptional activity from the PDE6β promoter in vitro. Our findings indicate that both the metabolic and transcriptional regulatory functions of PKM2 may contribute to photoreceptor structure, function, and viability.
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Rajala A, Wang Y, Abcouwer SF, Gardner TW, Rajala RV. Developmental and light regulation of tumor suppressor protein PP2A in the retina. Oncotarget 2018; 9:1505-1523. [PMID: 29416710 PMCID: PMC5788578 DOI: 10.18632/oncotarget.23351] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 11/28/2017] [Indexed: 02/07/2023] Open
Abstract
Protein phosphatases are a group of universal enzymes that are responsible for the dephosphorylation of various proteins and enzymes in cells. Cellular signal transduction events are largely governed by the phosphorylation of key proteins. The length of cellular response depends on the activation of protein phosphatase that dephosphorylates the phosphate groups to halt a biological response, and fine-tune the defined cellular outcome. Dysregulation of these phosphatase(s) results in various disease phenotypes. The retina is a post-mitotic tissue, and oncogenic tyrosine and serine/ threonine kinase activities are important for retinal neuron survival. Aberrant activation of protein phosphatase(s) may have a negative effect on retinal neurons. In the current study, we characterized tumor suppressor protein phosphatase 2 (PP2A), a major serine/ threonine kinase with a broad substrate specificity. Our data suggest that PP2A is developmentally regulated in the retina, localized predominantly in the inner retina, and expressed in photoreceptor inner segments. Our findings indicate that PKCα and mTOR may serve as PP2A substrates. We found that light regulates PP2A activity. Our studies also suggest that rhodopsin regulates PP2A and its substrate(s) dephosphorylation. PP2A substrate phosphorylation is increased in mice lacking the A-subunit of PP2A. However, there is no accompanying effect on retina structure and function. Together, our findings suggest that controlling the activity of PP2A in the retina may be neuroprotective.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Yuhong Wang
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
| | - Steven F. Abcouwer
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, USA
- W.K. Kellogg Eye Center, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Thomas W. Gardner
- Department of Ophthalmology and Visual Sciences, University of Michigan Medical School, Ann Arbor, Michigan, USA
- W.K. Kellogg Eye Center, University of Michigan Medical School, Ann Arbor, Michigan, USA
| | - Raju V.S. Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
- Dean McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma, USA
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Bergeron Y, Bureau G, Laurier-Laurin MÉ, Asselin E, Massicotte G, Cyr M. Genetic Deletion of Akt3 Induces an Endophenotype Reminiscent of Psychiatric Manifestations in Mice. Front Mol Neurosci 2017; 10:102. [PMID: 28442992 PMCID: PMC5385361 DOI: 10.3389/fnmol.2017.00102] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 03/24/2017] [Indexed: 11/21/2022] Open
Abstract
The protein kinase B (PKB/Akt), found in three distinctive isoforms (PKBα/Akt1, PKBβ/Akt2, PKBγ/Akt3), is implicated in a variety of cellular processes such as cell development, growth and survival. Although Akt3 is the most expressed isoform in the brain, its role in cerebral functions is still unclear. In the present study, we investigated the behavioral, electrophysiological and biochemical consequences of Akt3 deletion in mice. Motor abilities, spatial navigation, recognition memory and LTP are intact in the Akt3 knockout (KO) mice. However, the prepulse inhibition, three-chamber social, forced swim, tail suspension, open field, elevated plus maze and light-dark transition tests revealed an endophenotype reminiscent of psychiatric manifestations such as schizophrenia, anxiety and depression. Biochemical investigations revealed that Akt3 deletion was associated with reduced levels of phosphorylated GSK3α/β at serine 21/9 in several brain regions, although Akt1 and Akt2 levels were unaffected. Notably, chronic administration of lithium, a mood stabilizer, restored the decreased phosphorylated GSK3α/β levels and rescued the depressive and anxiety-like behaviors in the Akt3 KO mice. Collectively, our data suggest that Akt3 might be a critical molecule underlying psychiatric-related behaviors in mice.
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Affiliation(s)
- Yan Bergeron
- Department of Medical Biology, Université du Québec à Trois-RivièresTrois-Rivières, QC, Canada
| | - Geneviève Bureau
- Department of Medical Biology, Université du Québec à Trois-RivièresTrois-Rivières, QC, Canada
| | | | - Eric Asselin
- Department of Medical Biology, Université du Québec à Trois-RivièresTrois-Rivières, QC, Canada
| | - Guy Massicotte
- Department of Medical Biology, Université du Québec à Trois-RivièresTrois-Rivières, QC, Canada
| | - Michel Cyr
- Department of Medical Biology, Université du Québec à Trois-RivièresTrois-Rivières, QC, Canada
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Neuroprotective Strategy in Retinal Degeneration: Suppressing ER Stress-Induced Cell Death via Inhibition of the mTOR Signal. Int J Mol Sci 2017; 18:ijms18010201. [PMID: 28106827 PMCID: PMC5297831 DOI: 10.3390/ijms18010201] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 01/13/2017] [Accepted: 01/16/2017] [Indexed: 12/11/2022] Open
Abstract
The retina is a specialized sensory organ, which is essential for light detection and visual formation in the human eye. Inherited retinal degenerations are a heterogeneous group of eye diseases that can eventually cause permanent vision loss. UPR (unfolded protein response) and ER (endoplasmic reticulum) stress plays an important role in the pathological mechanism of retinal degenerative diseases. mTOR (the mammalian target of rapamycin) kinase, as a signaling hub, controls many cellular processes, covering protein synthesis, RNA translation, ER stress, and apoptosis. Here, the hypothesis that inhibition of mTOR signaling suppresses ER stress-induced cell death in retinal degenerative disorders is discussed. This review surveys knowledge of the influence of mTOR signaling on ER stress arising from misfolded proteins and genetic mutations in retinal degenerative diseases and highlights potential neuroprotective strategies for treatment and therapeutic implications.
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Chen S, Liu Y, Rong X, Li Y, Zhou J, Lu L. Neuroprotective Role of the PI3 Kinase/Akt Signaling Pathway in Zebrafish. Front Endocrinol (Lausanne) 2017; 8:21. [PMID: 28228749 PMCID: PMC5296330 DOI: 10.3389/fendo.2017.00021] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/31/2016] [Accepted: 01/23/2017] [Indexed: 12/27/2022] Open
Abstract
Neuronal survival and growth in the embryo is controlled partly by trophic factors. For most trophic factors (such as Insulin-like growth factor-1), the ability to regulate cell survival has been attributed to the phosphoinositide 3-kinase (PI3K)/Akt kinase cascade. This study presents data illustrating the role of PI3K/Akt in attainment of normal brain size during zebrafish embryogenesis. Blocking PI3K with inhibitor LY294002 caused a significant reduction in brain size (in addition to global growth retardation) during zebrafish embryogenesis. This PI3 Kinase inhibition-induced brain size decrease was recovered by the overexpression of myristoylated Akt (myr-Akt), a constitutive form of Akt. Further analysis reveals that expressing exogenous myr-Akt significantly augmented brain size. Whole mount in situ hybridization analysis of several marker genes showed that myr-Akt overexpression did not alter brain patterning. Furthermore, the expression of myr-Akt was found to protect neuronal cells from apoptosis induced by heat shock and UV light, suggesting that inhibition of neuronal cell death may be part of the underlying cause of the increased brain size. These data provide a foundation for addressing the role of PI3K/Akt in brain growth during zebrafish embryogenesis.
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Affiliation(s)
- Shuang Chen
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, Shandong, China
| | - Yunzhang Liu
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, Shandong, China
| | - Xiaozhi Rong
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, Shandong, China
| | - Yun Li
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, Shandong, China
| | - Jianfeng Zhou
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, Shandong, China
| | - Ling Lu
- Key Laboratory of Marine Drugs (Ocean University of China), Chinese Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, Shandong, China
- *Correspondence: Ling Lu,
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32
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The Warburg Effect Mediator Pyruvate Kinase M2 Expression and Regulation in the Retina. Sci Rep 2016; 6:37727. [PMID: 27883057 PMCID: PMC5121888 DOI: 10.1038/srep37727] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Accepted: 10/31/2016] [Indexed: 01/06/2023] Open
Abstract
The tumor form of pyruvate kinase M2 (PKM2) undergoes tyrosine phosphorylation and gives rise to the Warburg effect. The Warburg effect defines a pro-oncogenic metabolism switch such that cancer cells take up more glucose than normal tissue and favor incomplete oxidation of glucose, even in the presence of oxygen. Retinal photoreceptors are highly metabolic and their energy consumption is equivalent to that of a multiplying tumor cell. In the present study, we found that PKM2 is the predominant isoform in both rod- and cone-dominant retina, and that it undergoes a light-dependent tyrosine phosphorylation. We also discovered that PKM2 phosphorylation is signaled through photobleaching of rhodopsin. Our findings suggest that phosphoinositide 3-kinase activation promotes PKM2 phosphorylation. Light and tyrosine phosphorylation appear to regulate PKM2 to provide a metabolic advantage to photoreceptor cells, thereby promoting cell survival.
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Gianesini C, Hiragaki S, Laurent V, Hicks D, Tosini G. Cone Viability Is Affected by Disruption of Melatonin Receptors Signaling. Invest Ophthalmol Vis Sci 2016; 57:94-104. [PMID: 26780313 PMCID: PMC4727519 DOI: 10.1167/iovs.15-18235] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Purpose Previous studies have demonstrated that melatonin has an important role in the modulation of photoreceptor viability during aging and may be involved in the pathogenesis of age-related macular degeneration.This hormone exerts its influence by binding to G-protein coupled receptors named melatonin receptor 1 (MT1) and 2 (MT2). Melatonin receptors 1 and 2 activate a wide variety of signaling pathways. Methods Melatonin-proficient mice (C3H/f+/+) and melatonin-proficient mice lacking MT1 or MT2 receptors (MT1−/− and MT2−/−) were used in this study. Mice were killed at the ages of 3 and 18 months, and photoreceptor viability was determined by counting nuclei number in the outer nuclear layer (ONL). Cones were identified by immunohistochemistry using peanut agglutinin (PNA) and green/red and blue opsin antibodies. Protein kinase B (AKT) and forkhead box O (FOXO1) were assessed by Western blotting and immunohistochemistry. Results The number of nuclei in the ONL was significantly reduced in C3Hf+/+, MT1−/−, and MT2−/− mice at 18 months of age with respect to 3-month-old animals. In 18-month-old MT1−/− and MT2−/− mice, but not in C3H/f+/+, the number of cones was significantly reduced with respect to young MT1−/− and MT2−/− mice or age-matched C3H/f+/+. In C3H/f+/+, activation of the AKT-FOXO1 pathway in the photoreceptors showed a significant difference between night and day. Conclusions Our data indicate that disruption of MT1/MT2 heteromer signaling induces a reduction in the number of photoreceptors during aging and also suggest that the AKT-FOXO1 survival pathway may be involved in the mechanism by which melatonin protects photoreceptors.
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Affiliation(s)
- Coralie Gianesini
- Department of Pharmacology and Toxicology and Neuroscience Institute Morehouse School of Medicine, Atlanta, Georgia, United States 2Centre National de la Recherche Scientifique Unités Propres de Recherche 3212, Institute for Cellular and Integrative Neuro
| | - Susumu Hiragaki
- Department of Pharmacology and Toxicology and Neuroscience Institute Morehouse School of Medicine, Atlanta, Georgia, United States
| | - Virginie Laurent
- Centre National de la Recherche Scientifique Unités Propres de Recherche 3212, Institute for Cellular and Integrative Neurosciences, Strasbourg, France
| | - David Hicks
- Centre National de la Recherche Scientifique Unités Propres de Recherche 3212, Institute for Cellular and Integrative Neurosciences, Strasbourg, France
| | - Gianluca Tosini
- Department of Pharmacology and Toxicology and Neuroscience Institute Morehouse School of Medicine, Atlanta, Georgia, United States
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Rajala RV, Kanan Y, Anderson RE. Photoreceptor Neuroprotection: Regulation of Akt Activation Through Serine/Threonine Phosphatases, PHLPP and PHLPPL. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 854:419-24. [DOI: 10.1007/978-3-319-17121-0_55] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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All Akt isoforms (Akt1, Akt2, Akt3) are involved in normal hearing, but only Akt2 and Akt3 are involved in auditory hair cell survival in the mammalian inner ear. PLoS One 2015; 10:e0121599. [PMID: 25811375 PMCID: PMC4374771 DOI: 10.1371/journal.pone.0121599] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2014] [Accepted: 02/17/2015] [Indexed: 11/19/2022] Open
Abstract
The kinase Akt is a key downstream mediator of the phosphoinositide-3-kinase signaling pathway and participates in a variety of cellular processes. Akt comprises three isoforms each encoded by a separate gene. There is evidence to indicate that Akt is involved in the survival and protection of auditory hair cells in vitro. However, little is known about the physiological role of Akt in the inner ear—especially in the intact animal. To elucidate this issue, we first analyzed the mRNA expression of the three Akt isoforms in the inner ear of C57/BL6 mice by real-time PCR. Next, we tested the susceptibility to gentamicin-induced auditory hair cell loss in isoform-specific Akt knockout mice compared to wild-types (C57/BL6) in vitro. To analyze the effect of gene deletion in vivo, hearing and cochlear microanatomy were evaluated in Akt isoform knockout animals. In this study, we found that all three Akt isoforms are expressed in the cochlea. Our results further indicate that Akt2 and Akt3 enhance hair cell resistance to ototoxicity, while Akt1 does not. Finally, we determined that untreated Akt1 and Akt2/Akt3 double knockout mice display significant hearing loss, indicating a role for these isoforms in normal hearing. Taken together, our results indicate that each of the Akt isoforms plays a distinct role in the mammalian inner ear.
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Rajala RVS, Ranjo-Bishop M, Wang Y, Rajala A, Anderson RE. The p110α isoform of phosphoinositide 3-kinase is essential for cone photoreceptor survival. Biochimie 2015; 112:35-40. [PMID: 25742742 DOI: 10.1016/j.biochi.2015.02.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 02/20/2015] [Indexed: 12/12/2022]
Abstract
Phosphoinositide 3-kinases (PI3Ks) are a family of lipid kinases that phosphorylates the 3'OH of the inositol ring of phosphoinositides (PIs). They are responsible for coordinating a diverse range of cellular functions. Class IA PI3K is a heterodimeric protein composed of a regulatory p85 and a catalytic p110 subunit. In this study, we conditionally deleted the p110α-subunit of PI3K in cone photoreceptor cells using the Cre-loxP system. Cone photoreceptors allow for color vision in bright light (daylight vision). Cone-specific deletion of p110α resulted in cone degeneration. Our studies suggest that PI3K signaling is essential for cone photoreceptor functions.
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Affiliation(s)
- Raju V S Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Physiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
| | - Michelle Ranjo-Bishop
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Yuhong Wang
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
| | - Robert E Anderson
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Department of Cell Biology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA; Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA
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Effect of knocking down the insulin receptor on mouse rod responses. Sci Rep 2015; 5:7858. [PMID: 25598343 PMCID: PMC4297982 DOI: 10.1038/srep07858] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 12/18/2014] [Indexed: 12/12/2022] Open
Abstract
Previous experiments have shown that the insulin receptor (IR) is expressed in mammalian rods and contributes to the protection of photoreceptors during bright-light exposure. The role of the insulin receptor in the production of the light response is however unknown. We have used suction-electrode recording to examine the responses of rods after conditionally knocking down the insulin receptor. Our results show that these IR knock-down rods have an accelerated decay of the light response and a small decrease in sensitivity by comparison to littermate WT rods. Our results indicate that the insulin receptor may have some role in controlling the rate of rod response decay, but they exclude a major role of the insulin receptor pathway in phototransduction.
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Abcouwer SF, Gardner TW. Diabetic retinopathy: loss of neuroretinal adaptation to the diabetic metabolic environment. Ann N Y Acad Sci 2014; 1311:174-90. [PMID: 24673341 DOI: 10.1111/nyas.12412] [Citation(s) in RCA: 162] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Diabetic retinopathy (DR) impairs vision of patients with type 1 and type 2 diabetes, associated with vascular dysfunction and occlusion, retinal edema, hemorrhage, and inappropriate growth of new blood vessels. The recent success of biologic treatments targeting vascular endothelial growth factor (VEGF) demonstrates that treating the vascular aspects in the later stages of the disease can preserve vision in many patients. It would also be highly desirable to prevent the onset of the disease or arrest its progression at a stage preceding the appearance of overt microvascular pathologies. The progression of DR is not necessarily linear but may follow a series of steps that evolve over the course of multiple years. Abundant data suggest that diabetes affects the entire neurovascular unit of the retina, with an early loss of neurovascular coupling, gradual neurodegeneration, gliosis, and neuroinflammation occurring before observable vascular pathologies. In this article, we consider the pathology of DR from the point of view that diabetes causes measurable dysfunctions in the complex integral network of cell types that produce and maintain human vision.
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Affiliation(s)
- Steven F Abcouwer
- Department of Ophthalmology and Visual Sciences, University of Michigan Kellogg Eye Center, Ann Arbor, Michigan
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Forkwa TK, Neumann ID, Tamm ER, Ohlmann A, Reber SO. Short-term psychosocial stress protects photoreceptors from damage via corticosterone-mediated activation of the AKT pathway. Exp Neurol 2014; 252:28-36. [DOI: 10.1016/j.expneurol.2013.11.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 11/09/2013] [Accepted: 11/14/2013] [Indexed: 01/22/2023]
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Rajala RVS, Basavarajappa DK, Dighe R, Rajala A. Spatial and temporal aspects and the interplay of Grb14 and protein tyrosine phosphatase-1B on the insulin receptor phosphorylation. Cell Commun Signal 2013; 11:96. [PMID: 24350791 PMCID: PMC3878334 DOI: 10.1186/1478-811x-11-96] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2013] [Accepted: 12/15/2013] [Indexed: 12/17/2022] Open
Abstract
Background Growth factor receptor-bound protein 14 (Grb14) is an adapter protein implicated in receptor tyrosine kinase signaling. Grb14 knockout studies highlight both the positive and negative roles of Grb14 in receptor tyrosine kinase signaling, in a tissue specific manner. Retinal cells are post-mitotic tissue, and insulin receptor (IR) activation is essential for retinal neuron survival. Retinal cells express protein tyrosine phosphatase-1B (PTP1B), which dephosphorylates IR and Grb14, a pseudosubstrate inhibitor of IR. This project asks the following major question: in retinal neurons, how does the IR overcome inactivation by PTP1B and Grb14? Results Our previous studies suggest that ablation of Grb14 results in decreased IR activation, due to increased PTP1B activity. Our research propounds that phosphorylation in the BPS region of Grb14 inhibits PTP1B activity, thereby promoting IR activation. We propose a model in which phosphorylation of the BPS region of Grb14 is the key element in promoting IR activation, and failure to undergo phosphorylation on Grb14 leads to both PTP1B and Grb14 exerting their negative roles in IR. Consistent with this hypothesis, we found decreased phosphorylation of Grb14 in diabetic type 1 Ins2Akita mouse retinas. Decreased retinal IR activation has previously been reported in this mouse line. Conclusions Our results suggest that phosphorylation status of the BPS region of Grb14 determines the positive or negative role it will play in IR signaling.
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Affiliation(s)
- Raju V S Rajala
- Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK 73104, USA.
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Romano G. The role of the dysfunctional akt-related pathway in cancer: establishment and maintenance of a malignant cell phenotype, resistance to therapy, and future strategies for drug development. SCIENTIFICA 2013; 2013:317186. [PMID: 24381788 PMCID: PMC3870877 DOI: 10.1155/2013/317186] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2013] [Accepted: 11/14/2013] [Indexed: 06/01/2023]
Abstract
Akt serine/threonine kinases, or PKB, are key players in the regulation of a wide variety of cellular activities, such as growth, proliferation, protection from apoptotic injuries, control of DNA damage responses and genome stability, metabolism, migration, and angiogenesis. The Akt-related pathway responds to the stimulation mediated by growth factors, cytokines, hormones, and several nutrients. Akt is present in three isoforms: Akt1, Akt2, and Akt3, which may be alternatively named PKB α , PKB β , and PKB γ , respectively. The Akt isoforms are encoded on three diverse chromosomes and their biological functions are predominantly distinct. Deregulations in the Akt-related pathway were observed in many human maladies, including cancer, cardiopathies, neurological diseases, and type-2 diabetes. This review discusses the significance of the abnormal activities of the Akt axis in promoting and sustaining malignancies, along with the development of tumor cell populations that exhibit enhanced resistance to chemo- and/or radiotherapy. This occurrence may be responsible for the relapse of the disease, which is unfortunately very often related to fatal consequences in patients.
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Affiliation(s)
- Gaetano Romano
- Department of Biology, College of Science and Technology, Temple University, Bio Life Science Building, Suite 456, 1900 N. 12th Street, Philadelphia, PA 19122, USA
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Inoue Y, Shimazawa M, Nakamura S, Imamura T, Sugitani S, Tsuruma K, Hara H. Protective effects of placental growth factor on retinal neuronal cell damage. J Neurosci Res 2013; 92:329-37. [PMID: 24293397 DOI: 10.1002/jnr.23316] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 09/02/2013] [Accepted: 09/23/2013] [Indexed: 11/10/2022]
Abstract
Placental growth factor (PlGF) is a member of the vascular endothelial growth factor family. Although it has been reported that PlGF protects against neuronal damage in the brain, little is known about the effects of PlGF in the retina. Therefore, we investigated the effects of PlGF on retinal neuronal cells. To evaluate the effects of PlGF against L-buthionine-(S,R)-sulfoximine (BSO)/glutamate cell death, oxygen-glucose deprivation (OGD)-induced cell death, and light-induced cell death, RGC-5 and 661W cells were used. We evaluated the mechanism responsible for the protective effects of PlGF against retinal neuronal cell death by performing the examinations with U1026, which is a mitogen-activated protein kinase (MEK) inhibitor, and LY294002, which is a phosphoinositide 3-kinase (PI3K) inhibitor. In addition, we measured caspase-3/7 activity in RGC-5 cells and 661W cells. PlGF protected against RGC-5 cell death induced by BSO/glutamate and OGD and against 661W cell death induced by light irradiation. Moreover, an anti-PlGF antibody negated these protective effects. The protective effects of PlGF against OGD-induced RGC-5 cell death and light-induced 661W cell death were suppressed by using an anti-PlGF antibody, U1026, and LY294002. Treatment with PlGF suppressed caspase-3/7 activity in both cell lines. We demonstrated for the first time that PlGF exerts a protective effect by inhibiting the activation of caspase-3/7 through the MEK and PI3K pathway in retinal neuronal cells. These data suggest that PlGF may be an important protective factor in the retina.
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Affiliation(s)
- Yuki Inoue
- Molecular Pharmacology, Department of Biofunctional Evaluation, Gifu Pharmaceutical University, Gifu, Japan
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Woodruff ML, Rajala A, Fain GL, Rajala RVS. Modulation of mouse rod photoreceptor responses by Grb14 protein. J Biol Chem 2013; 289:358-64. [PMID: 24273167 DOI: 10.1074/jbc.m113.517045] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Previous experiments have indicated that growth factor receptor-bound protein 14 (Grb14) may modulate rod photoreceptor cGMP-gated channels by decreasing channel affinity for cGMP; however, the function of Grb14 in rod physiology is not known. In this study, we examined the role of Grb14 by recording electrical responses from rods in which the gene for the Grb14 protein had been deleted. Suction-electrode recordings from single mouse rods showed that responses of dark-adapted Grb14(-/-) mice to brief flashes decayed more rapidly than strain-controlled wild type (WT) rods, with decreased values of both integration time and the exponential time course of decay (τREC). This result is consistent with an increase in channel affinity for cGMP produced by deletion of Grb14. However, Grb14(-/-) mouse rods also showed little change in dark current and a large and significant decrease in the limiting time constant τD, which are not consistent with an effect on channel affinity but seem rather to indicate modulation of the rate of inactivation of cyclic nucleotide phosphodiesterase 6 (PDE6). Grb14 has been reported to translocate from the inner to the outer segment in bright light, but we saw effects on response time course even in dark-adapted rods, although the effects were somewhat greater after rods had been adapted by exposure to bleaching illumination. Our results indicate that the mechanism of Grb14 action may be more complex than previously realized.
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Affiliation(s)
- Michael L Woodruff
- From the Department of Integrative Biology and Physiology, UCLA, Los Angeles, California 90095-7239
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Sugitani S, Tsuruma K, Ohno Y, Kuse Y, Yamauchi M, Egashira Y, Yoshimura S, Shimazawa M, Iwama T, Hara H. The potential neuroprotective effect of human adipose stem cells conditioned medium against light-induced retinal damage. Exp Eye Res 2013; 116:254-64. [PMID: 24076412 DOI: 10.1016/j.exer.2013.09.013] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2013] [Revised: 09/12/2013] [Accepted: 09/17/2013] [Indexed: 12/16/2022]
Abstract
Human adipose-derived stem cells (hASCs) are present in adult adipose tissue and have been reported to secrete various factors that have neuroprotective effects. In the present study, we examined whether hASC-conditioned medium (hASC-CM) was effective against experimental degenerative retinal disease. Mature adipocytes (MAs) and hASCs were isolated from human subcutaneous adipose tissue. The isolated hASCs were identified based on their capacity for bone and neural differentiation. The effects of hASC-CM against tunicamycin-, H2O2-, and light-induced retinal photoreceptor damage were evaluated in vitro by measuring cell death. Moreover, we identified various factors present in hASC-CM using antibody arrays. Retinal damage induced in mice by exposure to white light was studied in vivo, and photoreceptor damage was evaluated according to the thickness of the outer nuclear layer and electroretinography results. In addition, the effect of hASC-CM on Akt phosphorylation at Ser473 was confirmed by western blotting. Finally, the effects of the secreted proteins identified in the hASC-CM on light-induced damage were evaluated in vivo. Isolated hASCs differentiated to osteocytes and neurons. hASC-CM protected against tunicamycin-, H2O2-, and light-induced cell death. In addition, hASC-CM inhibited photoreceptor degeneration and retinal dysfunction after exposure to light. Several proteins secreted by hASCs, such as the tissue inhibitor of metalloproteinase-1 (TIMP-1) and the secreted protein acidic and rich in cysteine (SPARC), protected against light-induced damage in vitro and in vivo. The results of the present study showed that hASC-CM has neuroprotective effects against light-induced retinal damage and suggest that hASCs have a therapeutic potential in retinal degenerative diseases via their secreted proteins, without requiring transplantation.
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Affiliation(s)
- Sou Sugitani
- Department of Biofunctional Evaluation, Molecular Pharmacology, Gifu Pharmaceutical University, 1-25-4 Daigaku-nishi, Gifu 501-1196, Japan
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Rajala A, Gupta VK, Anderson RE, Rajala RVS. Light activation of the insulin receptor regulates mitochondrial hexokinase. A possible mechanism of retinal neuroprotection. Mitochondrion 2013; 13:566-76. [PMID: 23993956 DOI: 10.1016/j.mito.2013.08.005] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 08/03/2013] [Accepted: 08/15/2013] [Indexed: 12/23/2022]
Abstract
The serine/threonine kinase Akt has been shown to mediate the anti-apoptotic activity through hexokinase (HK)-mitochondria interaction. We previously reported that Akt activation in retinal rod photoreceptor cells is mediated through the light-dependent insulin receptor (IR)/PI3K pathway. Our data indicate that light-induced activation of IR/PI3K/Akt results in the translocation of HK-II to mitochondria. We also found that PHLPPL, a serine/threonine phosphatase, enhanced the binding of HK-II to mitochondria. We found a mitochondrial targeting signal in PHLPPL and our study suggests that Akt translocation to mitochondria could be mediated through PHLPPL. Our results suggest that the light-dependent IR/PI3K/Akt pathway regulates hexokinase-mitochondria interaction in photoreceptors. Down-regulation of IR signaling has been associated with ocular diseases of retinitis pigmentosa, diabetic retinopathy, and Leber Congenital Amaurosis-type 2, and agents that enhance the binding interaction between hexokinase and mitochondria may have therapeutic potential against these ocular diseases.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA; Dean A. McGee Eye Institute, Oklahoma City, OK 73104, USA
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Rajala A, Dighe R, Agbaga MP, Anderson RE, Rajala RVS. Insulin receptor signaling in cones. J Biol Chem 2013; 288:19503-15. [PMID: 23673657 DOI: 10.1074/jbc.m113.469064] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In humans, age-related macular degeneration and diabetic retinopathy are the most common disorders affecting cones. In retinitis pigmentosa (RP), cone cell death precedes rod cell death. Systemic administration of insulin delays the death of cones in RP mouse models lacking rods. To date there are no studies on the insulin receptor signaling in cones; however, mRNA levels of IR signaling proteins are significantly higher in cone-dominant neural retina leucine zipper (Nrl) knock-out mouse retinas compared with wild type rod-dominant retinas. We previously reported that conditional deletion of the p85α subunit of phosphoinositide 3-kinase (PI3K) in cones resulted in age-related cone degeneration, and the phenotype was not rescued by healthy rods, raising the question of why cones are not protected by the rod-derived cone survival factors. Interestingly, systemic administration of insulin has been shown to delay the death of cones in mouse models of RP lacking rods. These observations led to the hypothesis that cones may have their own endogenous neuroprotective pathway, or rod-derived cone survival factors may be signaled through cone PI3K. To test this hypothesis we generated p85α(-/-)/Nrl(-/-) double knock-out mice and also rhodopsin mutant mice lacking p85α and examined the effect of the p85α subunit of PI3K on cone survival. We found that the rate of cone degeneration is significantly faster in both of these models compared with respective mice with competent p85α. These studies suggest that cones may have their own endogenous PI3K-mediated neuroprotective pathway in addition to the cone viability survival signals derived from rods.
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Affiliation(s)
- Ammaji Rajala
- Department of Ophthalmology, University of Oklahoma Health Sciences Center and Dean A McGee Eye Institute, Oklahoma City, Oklahoma 73104, USA
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Rajala A, Dilly AK, Rajala RV. Protein tyrosine phosphatase-1B regulates the tyrosine phosphorylation of the adapter Grb2-associated binder 1 (Gab1) in the retina. Cell Commun Signal 2013; 11:20. [PMID: 23521888 PMCID: PMC3637500 DOI: 10.1186/1478-811x-11-20] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Accepted: 03/19/2013] [Indexed: 01/31/2023] Open
Abstract
BACKGROUND Gab1 (Grb2-associated binder 1) is a key coordinator that belongs to the insulin receptor substrate-1 like family of adaptor molecules and is tyrosine phosphorylated in response to various growth factors, cytokines, and numerous other molecules. Tyrosine phosphorylated Gab1 is able to recruit a number of signaling effectors including PI3K, SHP2 and PLC-γ. In this study, we characterized the localization and regulation of tyrosine phosphorylation of Gab1 in the retina. RESULTS Our immuno localization studies suggest that Gab1 is expressed in rod photoreceptor inner segments. We found that hydrogen peroxide activates the tyrosine phosphorylation of Gab1 ex vivo and hydrogen peroxide has been shown to inhibit the protein tyrosine phosphatase PTP1B activity. We found a stable association between the D181A substrate trap mutant of PTP1B and Gab1. Our studies suggest that PTP1B interacts with Gab1 through Tyrosine 83 and this residue may be the major PTP1B target residue on Gab1. We also found that Gab1 undergoes a light-dependent tyrosine phosphorylation and PTP1B regulates the phosphorylation state of Gab1. Consistent with these observations, we found an enhanced Gab1 tyrosine phosphorylation in PTP1B deficient mice and also in retinas treated ex vivo with a PTP1B specific allosteric inhibitor. CONCLUSIONS Our laboratory has previously reported that retinas deficient of PTP1B are resistant to light damage compared to wild type mice. Since Gab1 is negatively regulated by PTP1B, a part of the retinal neuroprotective effect we have observed previously in PTP1B deficient mice could be contributed by Gab1 as well. In summary, our data suggest that PTP1B regulates the phosphorylation state of retinal Gab1 in vivo.
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Affiliation(s)
- Ammaji Rajala
- Departments of Ophthalmology, University of Oklahoma Health Sciences Center, Oklahoma City, OK, 73104, USA.
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Qi Y, Chen L, Zhang L, Liu WB, Chen XY, Yang XG. Crocin prevents retinal ischaemia/reperfusion injury-induced apoptosis in retinal ganglion cells through the PI3K/AKT signalling pathway. Exp Eye Res 2013. [DOI: 10.1016/j.exer.2012.11.011] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Bordone MP, Lanzani MF, López-Costa JJ, Chianelli MS, Franco P, Sáenz DA, Rosenstein RE. Bacterial lipopolysaccharide protects the retina from light-induced damage. J Neurochem 2012; 122:392-403. [DOI: 10.1111/j.1471-4159.2012.07767.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Conservation and divergence of Grb7 family of Ras-binding domains. Protein Cell 2012; 3:60-70. [PMID: 22271596 DOI: 10.1007/s13238-012-2001-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Accepted: 12/14/2011] [Indexed: 10/14/2022] Open
Abstract
Ras proteins are signal-transducing GTPases that cycle between inactive GDP-bound and active GTP-bound forms. Ras is a prolific signaling molecule interacting with a spectrum of effector molecules and acting through more than one signaling pathway. The Ras-effector proteins contain a Ras-associating (RA) domain through which these associate with Ras in a GTP-dependent manner. The RA domain is highly conserved among the members of the growth factor receptor-bound (Grb) 7 family of proteins which includes Grb7, Grb10 and Grb14. Our laboratory has reported an unusual observation that RA domain of Grb14 binds to the C-terminal nucleotide binding site of cyclic nucleotide gated channel (CTRCNGA1) and inhibits the channel activity. Molecular modeling of the CTR-CNGA1 displays 50%-70% tertiary structural similarity towards Ras proteins. We named this region as Ras-like domain (RLD). The interaction between RA-Grb14 and RLD-CNGA1 is mediated through a simple protein-protein interaction temporally and spatially regulated by light and cGMP. It is interesting to note that Grb14 binds to GTPase-mutant Rab5, a Ras-related small GTPase whereas Grb10 binds only to GTP-bound form of active Rab5 but not to GTPase-defective mutant Rab5. These results suggest that Grb14 might have been evolved later in the evolution that binds to both Ras and nucleotide binding proteins such as CNGA1. Our studies also suggest that eukaryotic CNG channels could be evolved through a gene fusion between prokaryotic ion channels and cyclic nucleotide binding proteins, both of which might have undergone several sequence variations for functional adaptation during evolution.
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