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Basavarajappa D, Gupta V, Chitranshi N, Viswanathan D, Gupta V, Vander Wall R, Palanivel V, Mirzaei M, You Y, Klistorner A, Graham SL. Anti-inflammatory Effects of Siponimod in a Mouse Model of Excitotoxicity-Induced Retinal Injury. Mol Neurobiol 2023; 60:7222-7237. [PMID: 37542647 PMCID: PMC10657799 DOI: 10.1007/s12035-023-03535-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 07/22/2023] [Indexed: 08/07/2023]
Abstract
Glaucoma is a leading cause of permanent blindness worldwide and is characterized by neurodegeneration linked to progressive retinal ganglion cell (RGC) death, axonal damage, and neuroinflammation. Glutamate excitotoxicity mediated through N-methyl-D-aspartate (NMDA) receptors plays a crucial role in glaucomatous RGC loss. Sphingosine 1-phosphate receptors (S1PRs) are important mediators of neurodegeneration and neuroinflammation in the brain and the retina. Siponimod is an immunomodulatory drug for multiple sclerosis and is a selective modulator of S1PR subtypes 1 and 5 and has been shown to have beneficial effects on the central nervous system (CNS) in degenerative conditions. Our previous study showed that mice administered orally with siponimod protected inner retinal structure and function against acute NMDA excitotoxicity. To elucidate the molecular mechanisms behind these protective effects, we investigated the inflammatory pathways affected by siponimod treatment in NMDA excitotoxicity model. NMDA excitotoxicity resulted in the activation of glial cells coupled with upregulation of the inflammatory NF-kB pathway and increased expression of TNFα, IL1-β, and IL-6. Siponimod treatment significantly reduced glial activation and suppressed the pro-inflammatory pathways. Furthermore, NMDA-induced activation of NLRP3 inflammasome and upregulation of neurotoxic inducible nitric oxide synthase (iNOS) were significantly diminished with siponimod treatment. Our data demonstrated that siponimod induces anti-inflammatory effects via suppression of glial activation and inflammatory singling pathways that could protect the retina against acute excitotoxicity conditions. These findings provide insights into the anti-inflammatory effects of siponimod in the CNS and suggest a potential therapeutic strategy for neuroinflammatory conditions.
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Affiliation(s)
- Devaraj Basavarajappa
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW, 2109, Australia.
| | - Vivek Gupta
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW, 2109, Australia.
| | - Nitin Chitranshi
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW, 2109, Australia
| | - Deepa Viswanathan
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW, 2109, Australia
| | - Veer Gupta
- School of Medicine, Deakin University, Geelong, VIC, Australia
| | - Roshana Vander Wall
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW, 2109, Australia
| | - Viswanthram Palanivel
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW, 2109, Australia
| | - Mehdi Mirzaei
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW, 2109, Australia
| | - Yuyi You
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW, 2109, Australia
| | - Alexander Klistorner
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW, 2109, Australia
| | - Stuart L Graham
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW, 2109, Australia
- Save Sight Institute, The University of Sydney, Sydney, NSW, 2000, Australia
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Chitranshi N, Rajput R, Godinez A, Pushpitha K, Mirzaei M, Basavarajappa D, Gupta V, Sharma S, You Y, Galliciotti G, Salekdeh GH, Baker MS, Graham SL, Gupta VK. Neuroserpin gene therapy inhibits retinal ganglion cell apoptosis and promotes functional preservation in glaucoma. Mol Ther 2023; 31:2056-2076. [PMID: 36905120 PMCID: PMC10362384 DOI: 10.1016/j.ymthe.2023.03.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 01/27/2023] [Accepted: 03/07/2023] [Indexed: 03/12/2023] Open
Abstract
Our research has proven that the inhibitory activity of the serine protease inhibitor neuroserpin (NS) is impaired because of its oxidation deactivation in glaucoma. Using genetic NS knockout (NS-/-) and NS overexpression (NS+/+ Tg) animal models and antibody-based neutralization approaches, we demonstrate that NS loss is detrimental to retinal structure and function. NS ablation was associated with perturbations in autophagy and microglial and synaptic markers, leading to significantly enhanced IBA1, PSD95, beclin-1, and LC3-II/LC3-I ratio and reduced phosphorylated neurofilament heavy chain (pNFH) levels. On the other hand, NS upregulation promoted retinal ganglion cell (RGC) survival in wild-type and NS-/- glaucomatous mice and increased pNFH expression. NS+/+Tg mice demonstrated decreased PSD95, beclin-1, LC3-II/LC3-I ratio, and IBA1 following glaucoma induction, highlighting its protective role. We generated a novel reactive site NS variant (M363R-NS) resistant to oxidative deactivation. Intravitreal administration of M363R-NS was observed to rescue the RGC degenerative phenotype in NS-/- mice. These findings demonstrate that NS dysfunction plays a key role in the glaucoma inner retinal degenerative phenotype and that modulating NS imparts significant protection to the retina. NS upregulation protected RGC function and restored biochemical networks associated with autophagy and microglial and synaptic function in glaucoma.
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Affiliation(s)
- Nitin Chitranshi
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia.
| | - Rashi Rajput
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Angela Godinez
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Kanishka Pushpitha
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Mehdi Mirzaei
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Devaraj Basavarajappa
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Veer Gupta
- School of Medicine, Deakin University, Melbourne, VIC, Australia
| | - Samridhi Sharma
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Yuyi You
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Giovanna Galliciotti
- Institute of Neuropathology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Ghasem H Salekdeh
- School of Natural Sciences, Macquarie University, Macquarie Park, NSW 2109, Australia
| | - Mark S Baker
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Stuart L Graham
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Vivek K Gupta
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia.
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Basavarajappa D, Gupta V, Wall RV, Gupta V, Chitranshi N, Mirshahvaladi SSO, Palanivel V, You Y, Mirzaei M, Klistorner A, Graham SL. S1PR1 signaling attenuates apoptosis of retinal ganglion cells via modulation of cJun/Bim cascade and Bad phosphorylation in a mouse model of glaucoma. FASEB J 2023; 37:e22710. [PMID: 36520045 DOI: 10.1096/fj.202201346r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/09/2022] [Accepted: 12/02/2022] [Indexed: 12/23/2022]
Abstract
Glaucoma is a complex neurodegenerative disease characterized by optic nerve damage and apoptotic retinal ganglion cell (RGC) death, and is the leading cause of irreversible blindness worldwide. Among the sphingosine 1-phosphate receptors (S1PRs) family, S1PR1 is a highly expressed subtype in the central nervous system and has gained rapid attention as an important mediator of pathophysiological processes in the brain and the retina. Our recent study showed that mice treated orally with siponimod drug exerted neuroprotection via modulation of neuronal S1PR1 in experimental glaucoma. This study identified the molecular signaling pathway modulated by S1PR1 activation with siponimod treatment in RGCs in glaucomatous injury. We investigated the critical neuroprotective signaling pathway in vivo using mice deleted for S1PR1 in RGCs. Our results showed marked upregulation of the apoptotic pathway was associated with decreased Akt and Erk1/2 activation levels in the retina in glaucoma conditions. Activation of S1PR1 with siponimod treatment significantly increased neuroprotective Akt and Erk1/2 activation and attenuated the apoptotic signaling via suppression of c-Jun/Bim cascade and by increasing Bad phosphorylation. Conversely, deletion of S1PR1 in RGCs significantly increased the apoptotic cells in the ganglion cell layer in glaucoma and diminished the neuroprotective effects of siponimod treatment on Akt/Erk1/2 activation, c-Jun/Bim cascade, and Bad phosphorylation. Our data demonstrated that activation of S1PR1 in RGCs induces crucial neuroprotective signaling that suppresses the proapoptotic c-Jun/Bim cascade and increases antiapoptotic Bad phosphorylation. Our findings suggest that S1PR1 is a potential therapeutic target for neuroprotection of RGCs in glaucoma.
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Affiliation(s)
- Devaraj Basavarajappa
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde Sydney, New South Wales, Australia
| | - Vivek Gupta
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde Sydney, New South Wales, Australia
| | - Roshana Vander Wall
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde Sydney, New South Wales, Australia
| | - Veer Gupta
- School of Medicine, Deakin University, Geelong, Victoria, Australia
| | - Nitin Chitranshi
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde Sydney, New South Wales, Australia
| | - Seyed Shahab Oddin Mirshahvaladi
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde Sydney, New South Wales, Australia
| | - Viswanthram Palanivel
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde Sydney, New South Wales, Australia
| | - Yuyi You
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde Sydney, New South Wales, Australia
| | - Mehdi Mirzaei
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde Sydney, New South Wales, Australia
| | - Alexander Klistorner
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde Sydney, New South Wales, Australia
| | - Stuart L Graham
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde Sydney, New South Wales, Australia
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Palanivel V, Gupta V, Mirshahvaladi SSO, Sharma S, Gupta V, Chitranshi N, Mirzaei M, Graham SL, Basavarajappa D. Neuroprotective Effects of Neuropeptide Y on Human Neuroblastoma SH-SY5Y Cells in Glutamate Excitotoxicity and ER Stress Conditions. Cells 2022; 11:cells11223665. [PMID: 36429093 PMCID: PMC9688085 DOI: 10.3390/cells11223665] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Revised: 11/15/2022] [Accepted: 11/16/2022] [Indexed: 11/19/2022] Open
Abstract
Neuropeptide Y (NPY), a sympathetic neurotransmitter, is involved in various physiological functions, and its dysregulation is implicated in several neurodegenerative diseases. Glutamate excitotoxicity, endoplasmic reticulum (ER) stress, and oxidative stress are the common mechanisms associated with numerous neurodegenerative illnesses. The present study aimed to elucidate the protective effects of NPY against glutamate toxicity and tunicamycin-induced ER stress in the human neuroblastoma SH-SY5Y cell line. We exposed the SH-SY5Y cells to glutamate and tunicamycin for two different time points and analyzed the protective effects of NPY at different concentrations. The protective effects of NPY treatments were assessed by cell viability assay, and the signalling pathway changes were evaluated by biochemical techniques such as Western blotting and immunofluorescence assays. Our results showed that treatment of SH-SY5Y cells with NPY significantly increased the viability of the cells in both glutamate toxicity and ER stress conditions. NPY treatments significantly attenuated the glutamate-induced pro-apoptotic activation of ERK1/2 and JNK/BAD pathways. The protective effects of NPY were further evident against tunicamycin-induced ER stress. NPY treatments significantly suppressed the ER stress activation by downregulating BiP, phospho-eIF2α, and CHOP expression. In addition, NPY alleviated the Akt/FoxO3a pathway in acute oxidative conditions caused by glutamate and tunicamycin in SH-SY5Y cells. Our results demonstrated that NPY is neuroprotective against glutamate-induced cell toxicity and tunicamycin-induced ER stress through anti-apoptotic actions.
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Affiliation(s)
- Viswanthram Palanivel
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
- Correspondence: (V.P.); (D.B.)
| | - Vivek Gupta
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
| | - Seyed Shahab Oddin Mirshahvaladi
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
| | - Samridhi Sharma
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
| | - Veer Gupta
- School of Medicine, Deakin University, Geelong, VIC 3216, Australia
| | - Nitin Chitranshi
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
| | - Mehdi Mirzaei
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
| | - Stuart L Graham
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
- Save Sight Institute, The University of Sydney, Sydney, NSW 2000, Australia
| | - Devaraj Basavarajappa
- Macquarie Medical School, Faculty of Medicine, Health and Human Sciences, Macquarie University, North Ryde, Sydney, NSW 2109, Australia
- Correspondence: (V.P.); (D.B.)
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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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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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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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Mirzaei M, Gupta VK, Chitranshi N, Deng L, Pushpitha K, Abbasi M, Chick JM, Rajput R, Wu Y, McKay MJ, Salekdeh GH, Gupta VB, Haynes PA, Graham SL. Retinal proteomics of experimental glaucoma model reveal intraocular pressure-induced mediators of neurodegenerative changes. J Cell Biochem 2020; 121:4931-4944. [PMID: 32692886 DOI: 10.1002/jcb.29822] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2019] [Revised: 02/27/2020] [Accepted: 06/16/2020] [Indexed: 12/11/2022]
Abstract
Current evidence suggests that exposure to chronically induced intraocular pressure (IOP) leads to neurodegenerative changes in the inner retina. This study aimed to determine retinal proteomic alterations in a rat model of glaucoma and compared findings with human retinal proteomics changes in glaucoma reported previously. We developed an experimental glaucoma rat model by subjecting the rats to increased IOP (9.3 ± 0.1 vs 20.8 ± 1.6 mm Hg) by weekly microbead injections into the eye (8 weeks). The retinal tissues were harvested from control and glaucomatous eyes and protein expression changes analysed using a multiplexed quantitative proteomics approach (TMT-MS3). Immunofluorescence was performed for selected protein markers for data validation. Our study identified 4304 proteins in the rat retinas. Out of these, 139 proteins were downregulated (≤0.83) while the expression of 109 proteins was upregulated (≥1.2-fold change) under glaucoma conditions (P ≤ .05). Computational analysis revealed reduced expression of proteins associated with glutathione metabolism, mitochondrial dysfunction/oxidative phosphorylation, cytoskeleton, and actin filament organisation, along with increased expression of proteins in coagulation cascade, apoptosis, oxidative stress, and RNA processing. Further functional network analysis highlighted the differential modulation of nuclear receptor signalling, cellular survival, protein synthesis, transport, and cellular assembly pathways. Alterations in crystallin family, glutathione metabolism, and mitochondrial dysfunction associated proteins shared similarities between the animal model of glaucoma and the human disease condition. In contrast, the activation of the classical complement pathway and upregulation of cholesterol transport proteins were exclusive to human glaucoma. These findings provide insights into the neurodegenerative mechanisms that are specifically affected in the retina in response to chronically elevated IOP.
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Affiliation(s)
- Mehdi Mirzaei
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
- Department of Clinical Medicine, Macquarie University, Sydney, Australia
- Australian Proteome Analysis Facility, Macquarie University, Sydney, Australia
| | - Vivek K Gupta
- Department of Clinical Medicine, Macquarie University, Sydney, Australia
| | - Nitin Chitranshi
- Department of Clinical Medicine, Macquarie University, Sydney, Australia
| | | | - Kanishka Pushpitha
- Department of Clinical Medicine, Macquarie University, Sydney, Australia
| | - Mojdeh Abbasi
- Department of Clinical Medicine, Macquarie University, Sydney, Australia
| | - Joel M Chick
- Department of Cell Biology, Harvard Medical School, Boston, Massachusetts
| | - Rashi Rajput
- Department of Clinical Medicine, Macquarie University, Sydney, Australia
| | - Yunqi Wu
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
- Australian Proteome Analysis Facility, Macquarie University, Sydney, Australia
| | - Matthew J McKay
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
- Australian Proteome Analysis Facility, Macquarie University, Sydney, Australia
| | - Ghasem H Salekdeh
- Department of Molecular Systems Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Veer B Gupta
- School of Medicine, Deakin University, Melbourne, Australia
| | - Paul A Haynes
- Department of Molecular Sciences, Macquarie University, Sydney, Australia
| | - Stuart L Graham
- Department of Clinical Medicine, Macquarie University, Sydney, Australia
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9
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Joseph C, Mangani AS, Gupta V, Chitranshi N, Shen T, Dheer Y, Kb D, Mirzaei M, You Y, Graham SL, Gupta V. Cell Cycle Deficits in Neurodegenerative Disorders: Uncovering Molecular Mechanisms to Drive Innovative Therapeutic Development. Aging Dis 2020; 11:946-966. [PMID: 32765956 PMCID: PMC7390532 DOI: 10.14336/ad.2019.0923] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2019] [Accepted: 09/23/2019] [Indexed: 12/12/2022] Open
Abstract
Cell cycle dysregulation has been implicated in the pathogenesis of neurodegenerative disorders. Specialised function obligates neuronal cells to subsist in a quiescent state of cell cycle once differentiated and therefore the circumstances and mechanisms underlying aberrant cell cycle activation in post-mitotic neurons in physiological and disease conditions remains an intriguing area of research. There is a strict requirement of concurrence to cell cycle regulation for neurons to ensure intracellular biochemical conformity as well as interrelationship with other cells within neural tissues. This review deliberates on various mechanisms underlying cell cycle regulation in neuronal cells and underscores potential implications of their non-compliance in neural pathology. Recent research suggests that successful duplication of genetic material without subsequent induction of mitosis induces inherent molecular flaws that eventually assert as apoptotic changes. The consequences of anomalous cell cycle activation and subsequent apoptosis are demonstrated by the increased presence of molecular stress response and apoptotic markers. This review delineates cell cycle events under normal physiological conditions and deficits amalgamated by alterations in protein levels and signalling pathways associated with cell-division are analysed. Cell cycle regulators essentially, cyclins, CDKs, cip/kip family of inhibitors, caspases, bax and p53 have been identified to be involved in impaired cell cycle regulation and associated with neural pathology. The pharmacological modulators of cell cycle that are shown to impart protection in various animal models of neurological deficits are summarised. Greater understanding of the molecular mechanisms that are indispensable to cell cycle regulation in neurons in health and disease conditions will facilitate targeted drug development for neuroprotection.
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Affiliation(s)
- Chitra Joseph
- 1Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | | | - Veer Gupta
- 2School of Medicine, Deakin University, Melbourne, VIC, Australia
| | - Nitin Chitranshi
- 1Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Ting Shen
- 1Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Yogita Dheer
- 1Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Devaraj Kb
- 1Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
| | - Mehdi Mirzaei
- 3Department of Molecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia
| | - Yuyi You
- 1Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia.,4Save Sight Institute, Sydney University, Sydney, NSW 2109, Australia
| | - Stuart L Graham
- 1Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia.,4Save Sight Institute, Sydney University, Sydney, NSW 2109, Australia
| | - Vivek Gupta
- 1Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia
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Chitranshi N, Gupta VK, Rajput R, Godinez A, Pushpitha K, Shen T, Mirzaei M, You Y, Basavarajappa D, Gupta V, Graham SL. Evolving geographic diversity in SARS-CoV2 and in silico analysis of replicating enzyme 3CL pro targeting repurposed drug candidates. J Transl Med 2020; 18:278. [PMID: 32646487 PMCID: PMC7344048 DOI: 10.1186/s12967-020-02448-z] [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: 05/08/2020] [Accepted: 07/06/2020] [Indexed: 12/15/2022] Open
Abstract
Background Severe acute respiratory syndrome (SARS) has been initiating pandemics since the beginning of the century. In December 2019, the world was hit again by a devastating SARS episode that has so far infected almost four million individuals worldwide, with over 200,000 fatalities having already occurred by mid-April 2020, and the infection rate continues to grow exponentially. SARS coronavirus 2 (SARS-CoV-2) is a single stranded RNA pathogen which is characterised by a high mutation rate. It is vital to explore the mutagenic capability of the viral genome that enables SARS-CoV-2 to rapidly jump from one host immunity to another and adapt to the genetic pool of local populations. Methods For this study, we analysed 2301 complete viral sequences reported from SARS-CoV-2 infected patients. SARS-CoV-2 host genomes were collected from The Global Initiative on Sharing All Influenza Data (GISAID) database containing 9 genomes from pangolin-CoV origin and 3 genomes from bat-CoV origin, Wuhan SARS-CoV2 reference genome was collected from GeneBank database. The Multiple sequence alignment tool, Clustal Omega was used for genomic sequence alignment. The viral replicating enzyme, 3-chymotrypsin-like cysteine protease (3CLpro) that plays a key role in its pathogenicity was used to assess its affinity with pharmacological inhibitors and repurposed drugs such as anti-viral flavones, biflavanoids, anti-malarial drugs and vitamin supplements. Results Our results demonstrate that bat-CoV shares > 96% similar identity, while pangolin-CoV shares 85.98% identity with Wuhan SARS-CoV-2 genome. This in-depth analysis has identified 12 novel recurrent mutations in South American and African viral genomes out of which 3 were unique in South America, 4 unique in Africa and 5 were present in-patient isolates from both populations. Using state of the art in silico approaches, this study further investigates the interaction of repurposed drugs with the SARS-CoV-2 3CLpro enzyme, which regulates viral replication machinery. Conclusions Overall, this study provides insights into the evolving mutations, with implications to understand viral pathogenicity and possible new strategies for repurposing compounds to combat the nCovid-19 pandemic.
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Affiliation(s)
- Nitin Chitranshi
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia.
| | - Vivek K Gupta
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia.
| | - Rashi Rajput
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Angela Godinez
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Kanishka Pushpitha
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Ting Shen
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Mehdi Mirzaei
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia.,Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Yuyi You
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Devaraj Basavarajappa
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Veer Gupta
- School of Medicine, Deakin University, Melbourne, VIC, Australia
| | - Stuart L Graham
- Faculty of Medicine, Health and Human Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia.,Save Sight Institute, Sydney University, Sydney, NSW, 2000, Australia
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11
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Abbasi M, Gupta VK, Chitranshi N, Gupta VB, Mirzaei M, Dheer Y, Garthwaite L, Zaw T, Parton RG, You Y, Graham SL. Caveolin-1 Ablation Imparts Partial Protection Against Inner Retinal Injury in Experimental Glaucoma and Reduces Apoptotic Activation. Mol Neurobiol 2020; 57:3759-3784. [PMID: 32578008 DOI: 10.1007/s12035-020-01948-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 05/13/2020] [Indexed: 12/16/2022]
Abstract
Retinal ganglion cell degeneration is a characteristic feature of glaucoma, and accordingly, protection of these cells constitutes a major therapeutic objective in the disease. Here, we demonstrate the key influence of caveolin (Cav) in regulating the inner retinal homeostasis in two models of experimentally elevated intraocular pressure (IOP). Two groups of Cav-1-/- and wild-type mice were used in the study. Animals were subjected to experimentally induced chronic and acutely elevated IOP and any changes in their retinal function were assessed by positive scotopic threshold response recordings. TUNEL and cleaved caspase-3 assays were performed to evaluate apoptotic changes in the retina while Brn3a immunostaining was used as a marker to assess and quantify ganglion cell layer (GCL) changes. H&E staining was carried out on retinal sections to evaluate histological differences in retinal laminar structure. Cav-1 ablation partially protected the inner retinal function in both chronic and acute models of elevated IOP. The protective effects of Cav-1 loss were also evident histologically by reduced loss of GCL density in both models. The phenotypic protection in Cav-1-/- glaucoma mice paralleled with increased TrkB phosphorylation and reduced endoplasmic reticulum stress markers and apoptotic activation in the inner retinas. This study corroborated previous findings of enhanced Shp2 phosphorylation in a chronic glaucoma model and established a novel role of Cav-1 in mediating activation of this phosphatase in the inner retina in vivo. Collectively, these findings highlight the critical involvement of Cav-1 regulatory mechanisms in ganglion cells in response to increased IOP, implicating Cav-1 as a potential therapeutic target in glaucoma.
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Affiliation(s)
- Mojdeh Abbasi
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Vivek K Gupta
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia.
| | - Nitin Chitranshi
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia.
| | - Veer B Gupta
- School of Medicine, Deakin University, Melbourne, VIC, Australia
| | - Mehdi Mirzaei
- Department of Molecular Science, Macquarie University, North Ryde, NSW, 2109, Australia.,Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Yogita Dheer
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Linda Garthwaite
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia
| | - Thiri Zaw
- Department of Molecular Science, Macquarie University, North Ryde, NSW, 2109, Australia
| | - Robert G Parton
- Institute for Molecular Bioscience and Centre for Microscopy and Microanalysis, The University of Queensland, Brisbane, Queensland, 4072, Australia.,Institute for Molecular Bioscience, The University of Queensland, QLD, Brisbane, Australia
| | - Yuyi You
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia.,Save Sight Institute, Sydney University, Sydney, NSW, 2000, Australia
| | - Stuart L Graham
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW, 2109, Australia.,Save Sight Institute, Sydney University, Sydney, NSW, 2000, Australia
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12
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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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13
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Deng L, Haynes PA, Wu Y, Amirkhani A, Kamath KS, Wu JX, Pushpitha K, Gupta V, Graham S, Gupta VK, Mirzaei M. Amyloid-beta peptide neurotoxicity in human neuronal cells is associated with modulation of insulin-like growth factor transport, lysosomal machinery and extracellular matrix receptor interactions. Neural Regen Res 2020; 15:2131-2142. [PMID: 32394972 PMCID: PMC7716038 DOI: 10.4103/1673-5374.282261] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Extracellular deposits of the amyloid-beta peptide (Aβ) are known as the main pathological hallmark of Alzheimer’s disease. In Alzheimer’s disease, neurons are injured and die throughout the brain, a process in which Aβ neurotoxicity is considered to play an important role. However, the molecular mechanisms underlying Aβ toxicity that lead to neurodegeneration are not clearly established. Here we have elucidated the molecular pathways and networks which are impacted by Aβ in neurons using SH-SY5Y human neuroblastoma cells as a model. These cells were treated with Aβ1–42 peptides to study changes in biochemical networks using tandem mass tag labeled quantitative proteomic technique followed by computational analysis of the data. The molecular impacts of Aβ on cells were evident in a time- and dose-dependent manner, albeit the duration of treatment induced greater differential changes in cellular proteome compared to the effects of concentration. Aβ induced early changes in proteins associated with lysosomes, collagen chain trimerization and extracellular matrix receptor interaction, complement and coagulation cascade, oxidative stress induced senescence, ribosome biogenesis, regulation of insulin-like growth factor transport and uptake by insulin-like growth factor-binding protein. These novel findings provide molecular insights on the effects of Aβ on neurons, with implications for better understanding the impacts of Aβ on early neurodegeneration in Alzheimer’s disease pathology.
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Affiliation(s)
- Liting Deng
- Department of Molecular Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW, Australia
| | - Paul A Haynes
- Department of Molecular Sciences, Faculty of Science and Engineering, Macquarie University, Sydney, NSW, Australia
| | - Yunqi Wu
- Australian Proteome Analysis Facility (APAF), Macquarie University, Sydney, NSW, Australia
| | - Ardeshir Amirkhani
- Australian Proteome Analysis Facility (APAF), Macquarie University, Sydney, NSW, Australia
| | | | - Jemma X Wu
- Australian Proteome Analysis Facility (APAF), Macquarie University, Sydney, NSW, Australia
| | - Kanishka Pushpitha
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Veer Gupta
- School of Medicine, Deakin University, Geelong, VIC, Australia
| | - Stuart Graham
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Vivek K Gupta
- Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
| | - Mehdi Mirzaei
- Department of Molecular Sciences, Faculty of Science and Engineering; Australian Proteome Analysis Facility (APAF); Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW, Australia
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14
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Loss of Shp2 Rescues BDNF/TrkB Signaling and Contributes to Improved Retinal Ganglion Cell Neuroprotection. Mol Ther 2018; 27:424-441. [PMID: 30341011 DOI: 10.1016/j.ymthe.2018.09.019] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 09/18/2018] [Accepted: 09/27/2018] [Indexed: 12/21/2022] Open
Abstract
Glaucoma is characterized by the loss of retinal ganglion cells (RGC), and accordingly the preservation of RGCs and their axons has recently attracted significant attention to improve therapeutic outcomes in the disease. Here, we report that Src homology region 2-containing protein tyrosine phosphatase 2 (Shp2) undergoes activation in the RGCs, in animal model of glaucoma as well as in the human glaucoma tissues and that Shp2 dephosphorylates tropomyosin receptor kinase B (TrkB) receptor, leading to reduced BDNF/TrkB neuroprotective survival signaling. This was elucidated by specifically modulating Shp2 expression in the RGCs in vivo, using adeno-associated virus serotype 2 (AAV2) constructs. Shp2 upregulation promoted endoplasmic reticulum (ER) stress and apoptosis, along with functional and structural deficits in the inner retina. In contrast, loss of Shp2 decelerated the loss of RGCs, preserved their function, and suppressed ER stress and apoptosis in glaucoma. This report constitutes the first identification of Shp2-mediated TrkB regulatory mechanisms in the RGCs that can become a potential therapeutic target in both glaucoma and other neurodegenerative disorders.
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15
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Activation of oncogenic tyrosine kinase signaling promotes insulin receptor-mediated cone photoreceptor survival. Oncotarget 2018; 7:46924-46942. [PMID: 27391439 PMCID: PMC5216914 DOI: 10.18632/oncotarget.10447] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 06/26/2016] [Indexed: 01/18/2023] Open
Abstract
In humans, daylight vision is primarily mediated by cone photoreceptors. These cells die in age-related retinal degenerations. Prolonging the life of cones for even one decade would have an enormous beneficial effect on usable vision in an aging population. Photoreceptors are postmitotic, but shed 10% of their outer segments daily, and must synthesize the membrane and protein equivalent of a proliferating cell each day. Although activation of oncogenic tyrosine kinase and inhibition of tyrosine phosphatase signaling is known to be essential for tumor progression, the cellular regulation of this signaling in postmitotic photoreceptor cells has not been studied. In the present study, we report that a novel G-protein coupled receptor–mediated insulin receptor (IR) signaling pathway is regulated by non-receptor tyrosine kinase Src through the inhibition of protein tyrosine phosphatase IB (PTP1B). We demonstrated the functional significance of this pathway through conditional deletion of IR and PTP1B in cones, in addition to delaying the death of cones in a mouse model of cone degeneration by activating the Src. This is the first study demonstrating the molecular mechanism of a novel signaling pathway in photoreceptor cells, which provides a window of opportunity to save the dying cones in retinal degenerative diseases.
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16
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Chitranshi N, Dheer Y, Gupta V, Abbasi M, Mirzaei M, You Y, Chung R, Graham SL, Gupta V. PTPN11 induces endoplasmic stress and apoptosis in SH-SY5Y cells. Neuroscience 2017; 364:175-189. [PMID: 28947394 DOI: 10.1016/j.neuroscience.2017.09.028] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Revised: 09/13/2017] [Accepted: 09/14/2017] [Indexed: 12/25/2022]
Abstract
PTPN11 is associated with regulation of growth factor signaling pathways in neuronal cells. Using SH-SY5Y neuroblastoma cells, we showed that adeno-associated virus (AAV)-mediated PTPN11 upregulation was associated with TrkB antagonism, reduced neuritogenesis and enhanced endoplasmic reticulum (ER) stress response leading to apoptotic changes. Genetic knock-down of PTPN11 on the other hand leads to increased TrkB phosphorylation in SH-SY5Y cells. ER stress response induced by PTPN11 upregulation was alleviated pharmacologically by a TrkB agonist. Conversely the enhanced ER stress response induced by TrkB receptor antagonism was ameliorated by PTPN11 suppression, providing evidence of cross-talk of PTPN11 effects with TrkB actions. BDNF treatment of neuronal cells with PTPN11 upregulation also resulted in reduced expression of ER stress protein markers. This study provides evidence of molecular interactions between PTPN11 and the TrkB receptor in SH-SY5Y cells. The results reinforce the role played by PTPN11 in regulating neurotrophin protective signaling in neuronal cells and highlight that PTPN11 dysregulation promotes apoptotic activation. Based on these findings we suggest that blocking PTPN11 could have potential beneficial effects to limit the progression of neuronal loss in neurodegenerative disorders.
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Affiliation(s)
- Nitin Chitranshi
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW 2109, Australia.
| | - Yogita Dheer
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW 2109, Australia
| | - Veer Gupta
- School of Medical Sciences, Edith Cowan University, Perth, Australia
| | - Mojdeh Abbasi
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW 2109, Australia
| | - Mehdi Mirzaei
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW 2109, Australia; Department of Chemistry and Biomolecular Sciences, Macquarie University, North Ryde, NSW 2109, Australia; Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW 2109, Australia
| | - Yuyi You
- Save Sight Institute, Sydney University, Sydney, NSW 2000, Australia
| | - Roger Chung
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW 2109, Australia
| | - Stuart L Graham
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW 2109, Australia; Save Sight Institute, Sydney University, Sydney, NSW 2000, Australia
| | - Vivek Gupta
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW 2109, Australia
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17
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Chitranshi N, Dheer Y, Wall RV, Gupta V, Abbasi M, Graham SL, Gupta V. Computational analysis unravels novel destructive single nucleotide polymorphisms in the non-synonymous region of human caveolin gene. GENE REPORTS 2017. [DOI: 10.1016/j.genrep.2016.08.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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18
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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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19
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Gupta VK, Chitranshi N, Gupta VB, Golzan M, Dheer Y, Wall RV, Georgevsky D, King AE, Vickers JC, Chung R, Graham S. Amyloid β accumulation and inner retinal degenerative changes in Alzheimer's disease transgenic mouse. Neurosci Lett 2016; 623:52-6. [PMID: 27133194 DOI: 10.1016/j.neulet.2016.04.059] [Citation(s) in RCA: 90] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 03/31/2016] [Accepted: 04/26/2016] [Indexed: 11/26/2022]
Abstract
The APP-PS1ΔE9 mouse model of Alzheimer's disease (AD) exhibits age dependent amyloid β (Aβ) plaque formation in their central nervous system due to high expression of mutated human APP and PSEN1 transgenes. Here we evaluated Aβ deposition and changes in soluble Aβ accumulation in the retinas of aged APP-PS1 mice using a combination of immunofluorescence, retinal flat mounts and western blotting techniques. Aβ accumulation in the retina has previously been shown to be associated with retinal ganglion cell apoptosis in animal models of glaucoma. This study investigated changes in the inner retinal function and structure in APP-PS1 mice using electrophysiology and histological approaches respectively. We report for the first time a significant decline in scotopic threshold response (STR) amplitudes which represents inner retinal function in transgenic animals compared to the wild type counterparts (p<0.0001). Thinning of the retina particularly involving inner retinal layers and reduction in axonal density in the optic nerve was also observed. TUNEL staining was performed to examine neuronal apoptosis in the inner retina. Intraocular pressure (IOP) measurements showed that APP-PS1ΔE9 mice had a slightly elevated IOP, but the significance of this finding is not yet known. Together, these results substantiate previous observations and highlight that APP-PS1ΔE9 mice show evidence of molecular, functional and morphological degenerative changes in the inner retina.
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Affiliation(s)
- Vivek K Gupta
- Faculty of Medicine and Health sciences, Macquarie University, Australia.
| | - Nitin Chitranshi
- Faculty of Medicine and Health sciences, Macquarie University, Australia
| | - Veer B Gupta
- School of Medical Sciences, Edith Cowan University, Perth, Australia
| | - Mojtaba Golzan
- Faculty of Medicine and Health sciences, Macquarie University, Australia
| | - Yogita Dheer
- Faculty of Medicine and Health sciences, Macquarie University, Australia
| | | | - Dana Georgevsky
- Faculty of Medicine and Health sciences, Macquarie University, Australia
| | - Anna E King
- Wicking Dementia Research & Education Centre, School of Medicine, University of Tasmania, Australia
| | - James C Vickers
- Wicking Dementia Research & Education Centre, School of Medicine, University of Tasmania, Australia
| | - Roger Chung
- Faculty of Medicine and Health sciences, Macquarie University, Australia
| | - Stuart Graham
- Faculty of Medicine and Health sciences, Macquarie University, Australia; Save Sight Institute, Sydney University, Australia
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Chitranshi N, Gupta V, Dheer Y, Gupta V, Vander Wall R, Graham S. Molecular determinants and interaction data of cyclic peptide inhibitor with the extracellular domain of TrkB receptor. Data Brief 2016; 6:776-82. [PMID: 26909388 PMCID: PMC4744334 DOI: 10.1016/j.dib.2016.01.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 12/29/2015] [Accepted: 01/08/2016] [Indexed: 11/24/2022] Open
Abstract
TrkB is a high affinity receptor for the brain derived neurotrophic factor (BDNF) and its phosphorylation stimulates activation of several intracellular signalling pathways linked to cellular growth, differentiation and maintenance. Identification of various activators and inhibitors of the TrkB receptor and greater understanding their binding mechanisms is critical to elucidate the biochemical and pharmacological pathways and analyse various protein crystallization studies. The data presented here is related to the research article entitled “Brain Derived neurotrophic factor is involved in the regulation of glycogen synthase kinase 3β (GSK3β) signalling” [1]. Cyclotraxin B (CTXB) is a disulphide bridge linked cyclic peptide molecule that interacts with TrkB receptor and inhibits the BDNF/TrkB downstream signalling. This article reports for the first time binding mechanism and interaction parameters of CTXB with the TrkB receptor. The molecular model of CTXB has been generated and it’s docking with TrkB domain carried out to determine the critical residues involved in the protein peptide interaction.
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Affiliation(s)
- Nitin Chitranshi
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW 2109, Australia
| | - Vivek Gupta
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW 2109, Australia
| | - Yogita Dheer
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW 2109, Australia
| | - Veer Gupta
- School of Medical Sciences, Edith Cowan University, Perth, Australia
| | - Roshana Vander Wall
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW 2109, Australia
| | - Stuart Graham
- Faculty of Medicine and Health Sciences, Macquarie University, F10A, 2 Technology Place, North Ryde, NSW 2109, Australia; Save Sight Institute, Sydney University, Sydney, NSW 2109, Australia
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21
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Exploring the Molecular Interactions of 7,8-Dihydroxyflavone and Its Derivatives with TrkB and VEGFR2 Proteins. Int J Mol Sci 2015; 16:21087-108. [PMID: 26404256 PMCID: PMC4613243 DOI: 10.3390/ijms160921087] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 08/21/2015] [Accepted: 08/26/2015] [Indexed: 11/16/2022] Open
Abstract
7,8-dihydroxyflavone (7,8-DHF) is a TrkB receptor agonist, and treatment with this flavonoid derivative brings about an enhanced TrkB phosphorylation and promotes downstream cellular signalling. Flavonoids are also known to exert an inhibitory effect on the vascular endothelial growth factor receptor (VEGFR) family of tyrosine kinase receptors. VEGFR2 is one of the important receptors involved in the regulation of vasculogenesis and angiogenesis and has also been implicated to exhibit various neuroprotective roles. Its upregulation and uncontrolled activity is associated with a range of pathological conditions such as age-related macular degeneration and various proliferative disorders. In this study, we investigated molecular interactions of 7,8-DHF and its derivatives with both the TrkB receptor as well as VEGFR2. Using a combination of molecular docking and computational mapping tools involving molecular dynamics approaches we have elucidated additional residues and binding energies involved in 7,8-DHF interactions with the TrkB Ig2 domain and VEGFR2. Our investigations have revealed for the first time that 7,8-DHF has dual biochemical action and its treatment may have divergent effects on the TrkB via its extracellular Ig2 domain and on the VEGFR2 receptor through the intracellular kinase domain. Contrary to its agonistic effects on the TrkB receptor, 7,8-DHF was found to downregulate VEGFR2 phosphorylation both in 661W photoreceptor cells and in retinal tissue.
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22
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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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Gupta V, Chitranshi N, You Y, Gupta V, Klistorner A, Graham S. Brain derived neurotrophic factor is involved in the regulation of glycogen synthase kinase 3β (GSK3β) signalling. Biochem Biophys Res Commun 2014; 454:381-6. [PMID: 25451258 DOI: 10.1016/j.bbrc.2014.10.087] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 10/19/2014] [Indexed: 01/05/2023]
Abstract
Glycogen synthase kinase 3β (GSK3β) is involved in several biochemical processes in neurons regulating cellular survival, gene expression, cell fate determination, metabolism and proliferation. GSK3β activity is inhibited through the phosphorylation of its Ser-9 residue. In this study we sought to investigate the role of BDNF/TrkB signalling in the modulation of GSK3β activity. BDNF/TrkB signalling regulates the GSK3β activity both in vivo in the retinal tissue as well as in the neuronal cells under culture conditions. We report here for the first time that BDNF can also regulate GSK3β activity independent of its effects through the TrkB receptor signalling. Knockdown of BDNF lead to a decline in GSK3β phosphorylation without having a detectable effect on the TrkB activity or its downstream effectors Akt and Erk1/2. Treatment with TrkB receptor agonist had a stimulating effect on the GSK3β phosphorylation, but the effect was significantly less pronounced in the cells in which BDNF was knocked down. The use of TrkB receptor antagonist similarly, manifested itself in the form of downregulation of GSK3β phosphorylation, but a combined TrkB inhibition and BDNF knockdown exhibited a much stronger negative effect. In vivo, we observed reduced levels of GSK3β phosphorylation in the retinal tissues of the BDNF(+/-) animals implicating critical role of BDNF in the regulation of the GSK3β activity. Concluding, BDNF/TrkB axis strongly regulates the GSK3β activity and BDNF also exhibits GSK3β regulatory effect independent of its actions through the TrkB receptor signalling.
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Affiliation(s)
- Vivek Gupta
- Australian School of Advanced Medicine, Macquarie University, Australia.
| | - Nitin Chitranshi
- Australian School of Advanced Medicine, Macquarie University, Australia
| | - Yuyi You
- Australian School of Advanced Medicine, Macquarie University, Australia
| | - Veer Gupta
- School of Medical Sciences, Edith Cowan University, Perth, Australia
| | - Alexander Klistorner
- Australian School of Advanced Medicine, Macquarie University, Australia; Save Sight Institute, Sydney University, Sydney, Australia
| | - Stuart Graham
- Australian School of Advanced Medicine, Macquarie University, Australia; Save Sight Institute, Sydney University, Sydney, Australia
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24
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Gondoin A, Morzyglod L, Desbuquois B, Burnol AF. [Control of insulin signalisation and action by the Grb14 protein]. Biol Aujourdhui 2014; 208:119-36. [PMID: 25190572 DOI: 10.1051/jbio/2014013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Indexed: 11/15/2022]
Abstract
The action of insulin on metabolism and cell growth is mediated by a specific receptor tyrosine kinase, which, through phosphorylation of several substrates, triggers the activation of two major signaling pathways, the phosphatidylinositol 3-kinase (PI3-K)/Akt pathway and the Ras/extracellular signal-regulated kinase (ERK) pathway. Insulin-induced activation of the receptor and downstream signaling is also subjected to a negative feedback control involving several mechanisms, among which the interaction of the insulin receptor and its substrates with inhibitory proteins. After summarizing the major mechanisms underlying the activation and attenuation of insulin signaling, this review focuses on its control by the Grb14 adaptor protein. Grb14 has been identif-ied as an inhibitor of insulin signaling and action, and is involved in insulin resistance associated with type 2 diabetes and obesity. Studies on the molecular mechanism of action of Grb14 have shown that, through interaction with the activated insulin receptor, Grb14 inhibits its catalytic activity and the activation of downstream signaling. However, the consequences of Grb14 gene invalidation are complex and tissue-specific, and some effects of Grb14 on insulin signaling appear to be linked to its interaction with effector proteins downstream the insulin receptor. Pharmacological inhibition of Grb14 should allow to enhance insulin sensitivity and improve energy homeostasis in insulin-resistant states.
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Affiliation(s)
- Anaïs Gondoin
- INSERM, U1016, Institut Cochin, 22 rue Méchain, 75014 Paris, France - CNRS, UMR 8104, Institut Cochin, 22 rue Méchain, 75014 Paris, France - Université Paris Descartes, Sorbonne Paris Cité, 24 rue du Faubourg Saint Jacques, 75014 Paris, France
| | - Lucie Morzyglod
- INSERM, U1016, Institut Cochin, 22 rue Méchain, 75014 Paris, France - CNRS, UMR 8104, Institut Cochin, 22 rue Méchain, 75014 Paris, France - Université Paris Descartes, Sorbonne Paris Cité, 24 rue du Faubourg Saint Jacques, 75014 Paris, France
| | - Bernard Desbuquois
- INSERM, U1016, Institut Cochin, 22 rue Méchain, 75014 Paris, France - CNRS, UMR 8104, Institut Cochin, 22 rue Méchain, 75014 Paris, France - Université Paris Descartes, Sorbonne Paris Cité, 24 rue du Faubourg Saint Jacques, 75014 Paris, France
| | - Anne-Françoise Burnol
- INSERM, U1016, Institut Cochin, 22 rue Méchain, 75014 Paris, France - CNRS, UMR 8104, Institut Cochin, 22 rue Méchain, 75014 Paris, France - Université Paris Descartes, Sorbonne Paris Cité, 24 rue du Faubourg Saint Jacques, 75014 Paris, France
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25
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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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26
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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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27
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Ezzat S, Zheng L, Florez JC, Stefan N, Mayr T, Hliang MM, Jablonski K, Harden M, Stančáková A, Laakso M, Haring HU, Ullrich A, Asa SL. The cancer-associated FGFR4-G388R polymorphism enhances pancreatic insulin secretion and modifies the risk of diabetes. Cell Metab 2013; 17:929-940. [PMID: 23747250 PMCID: PMC4005358 DOI: 10.1016/j.cmet.2013.05.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2012] [Revised: 01/18/2013] [Accepted: 04/05/2013] [Indexed: 12/11/2022]
Abstract
The fibroblast growth factor receptor 4 (FGFR4)-R388 single-nucleotide polymorphism has been associated with cancer risk and prognosis. Here we show that the FGFR4-R388 allele yields a receptor variant that preferentially promotes STAT3/5 signaling. This STAT activation transcriptionally induces Grb14 in pancreatic endocrine cells to promote insulin secretion. Knockin mice with the FGFR4 variant allele develop pancreatic islets that secrete more insulin, a feature that is reversed through Grb14 deletion and enhanced with FGF19 administration. We also show in humans that the FGFR4-R388 allele enhances islet function and may protect against type 2 diabetes. These data support a common genetic link underlying cancer and hyperinsulinemia.
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Affiliation(s)
- Shereen Ezzat
- Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2M9, Canada.
| | - Lei Zheng
- Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2M9, Canada
| | - Jose C Florez
- Center for Human Genetic Research and Diabetes Research Center (Diabetes Unit), Massachusetts General Hospital, Boston, MA 02114, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA; Department of Medicine, Harvard Medical School, Boston, MA 02142, USA
| | | | - Thomas Mayr
- Department of Molecular Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Maw Maw Hliang
- Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2M9, Canada
| | - Kathleen Jablonski
- The Biostatistics Center, George Washington University, Rockville, MD 20852, USA
| | - Maegan Harden
- Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Alena Stančáková
- Department of Medicine, University of Eastern Finland, 70210 Kuopio, Finland
| | - Markku Laakso
- Department of Medicine, University of Eastern Finland, 70210 Kuopio, Finland
| | | | - Axel Ullrich
- Department of Molecular Biology, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Sylvia L Asa
- Ontario Cancer Institute, University Health Network, Toronto, ON M5G 2M9, Canada
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28
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TrkB receptor signalling: implications in neurodegenerative, psychiatric and proliferative disorders. Int J Mol Sci 2013; 14:10122-42. [PMID: 23670594 PMCID: PMC3676832 DOI: 10.3390/ijms140510122] [Citation(s) in RCA: 157] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 04/27/2013] [Accepted: 04/28/2013] [Indexed: 02/06/2023] Open
Abstract
The Trk family of receptors play a wide variety of roles in physiological and disease processes in both neuronal and non-neuronal tissues. Amongst these the TrkB receptor in particular has attracted major attention due to its critical role in signalling for brain derived neurotrophic factor (BDNF), neurotrophin-3 (NT3) and neurotrophin-4 (NT4). TrkB signalling is indispensable for the survival, development and synaptic plasticity of several subtypes of neurons in the nervous system. Substantial evidence has emerged over the last decade about the involvement of aberrant TrkB signalling and its compromise in various neuropsychiatric and degenerative conditions. Unusual changes in TrkB signalling pathway have also been observed and implicated in a range of cancers. Variations in TrkB pathway have been observed in obesity and hyperphagia related disorders as well. Both BDNF and TrkB have been shown to play critical roles in the survival of retinal ganglion cells in the retina. The ability to specifically modulate TrkB signalling can be critical in various pathological scenarios associated with this pathway. In this review, we discuss the mechanisms underlying TrkB signalling, disease implications and explore plausible ameliorative or preventive approaches.
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29
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Desbuquois B, Carré N, Burnol AF. Regulation of insulin and type 1 insulin-like growth factor signaling and action by the Grb10/14 and SH2B1/B2 adaptor proteins. FEBS J 2013. [PMID: 23190452 DOI: 10.1111/febs.12080] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The effects of insulin and type 1 insulin-like growth factor (IGF-1) on metabolism, growth and survival are mediated by their association with specific receptor tyrosine kinases, which results in both receptor and substrate phosphorylation. Phosphotyrosine residues on receptors and substrates provide docking sites for signaling proteins containing SH2 (Src homology 2) domains, including molecular adaptors. This review focuses on the regulation of insulin/IGF-1 signaling and action by two adaptor families with a similar domain organization: the growth factor receptor-bound proteins Grb7/10/14 and the SH2B proteins. Both Grb10/14 and SH2B1/B2 associate with the activation loop of insulin/IGF-1 receptors through their SH2 domains, but association of Grb10/14 also involves their unique BPS domain. Consistent with Grb14 binding as a pseudosubstrate to the kinase active site, insulin/IGF-induced activation of receptors and downstream signaling pathways in cultured cells is inhibited by Grb10/14 adaptors, but is potentiated by SH2B1/B2 adaptors. Accordingly, Grb10 and Grb14 knockout mice show improved insulin/IGF sensitivity in vivo, and, for Grb10, overgrowth and increased skeketal muscle and pancreatic β-cell mass. Conversely, SH2B1-depleted mice display insulin and IGF-1 resistance, with peripheral depletion leading to reduced adiposity and neuronal depletion leading to obesity through associated leptin resistance. Grb10/14 and SH2B1 adaptors also modulate insulin/IGF-1 action by interacting with signaling components downstream of receptors and exert several tissue-specific effects. The identification of Grb10/14 and SH2B1 as physiological regulators of insulin signaling and action, together with observations that variants at their gene loci are associated with obesity and/or insulin resistance, highlight them as potential therapeutic targets for these conditions.
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Affiliation(s)
- Bernard Desbuquois
- Institut Cochin, Départment d'Endocrinologie, Métabolisme et Cancer, Université Paris-Descartes, Institut National de la Santé et de la Recherche Médicale, Unité 1016, et Centre National de la Recherche Scientifique, Unité Mixte de Recherche, Paris, France
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30
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Abstract
Insulin resistance is a key pathological feature of type 2 diabetes and is characterized by defects in signaling by the insulin receptor (IR) protein tyrosine kinase. The inhibition of protein tyrosine phosphatases (PTPs) that antagonize IR signaling may provide a means for enhancing the insulin response and alleviating insulin resistance. The prototypic phosphotyrosine-specific phosphatase PTP1B dephosphorylates the IR and attenuates insulin signaling in muscle and liver. Mice that are deficient for PTP1B exhibit improved glucose homeostasis in diet and genetic models of insulin resistance and type 2 diabetes. The phosphatase TCPTP shares 72% catalytic domain sequence identity with PTP1B and has also been implicated in IR regulation. Despite their high degree of similarity, PTP1B and TCPTP act together in vitro and in vivo to regulate insulin signaling and glucose homeostasis. This review highlights their capacity to act specifically and nonredundantly in cellular signaling, describes their roles in IR regulation and glucose homeostasis, and discusses their potential as drug targets for the enhancement of IR phosphorylation and insulin sensitivity in type 2 diabetes.
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Affiliation(s)
- Tony Tiganis
- Department of Biochemistry and Molecular Biology, Monash University, Clayton, Australia.
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