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Pichavaram P, Palani CD, Patel C, Xu Z, Shosha E, Fouda AY, Caldwell RB, Narayanan SP. Targeting Polyamine Oxidase to Prevent Excitotoxicity-Induced Retinal Neurodegeneration. Front Neurosci 2019; 12:956. [PMID: 30686964 PMCID: PMC6335392 DOI: 10.3389/fnins.2018.00956] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 11/30/2018] [Indexed: 12/21/2022] Open
Abstract
Dysfunction of retinal neurons is a major cause of vision impairment in blinding diseases that affect children and adults worldwide. Cellular damage resulting from polyamine catabolism has been demonstrated to be a major player in many neurodegenerative conditions. We have previously shown that inhibition of polyamine oxidase (PAO) using MDL 72527 significantly reduced retinal neurodegeneration and cell death signaling pathways in hyperoxia-mediated retinopathy. In the present study, we investigated the impact of PAO inhibition in limiting retinal neurodegeneration in a model of NMDA (N-Methyl-D-aspartate)-induced excitotoxicity. Adult mice (8–10 weeks old) were given intravitreal injections (20 nmoles) of NMDA or NMLA (N-Methyl-L-aspartate, control). Intraperitoneal injection of MDL 72527 (40 mg/kg body weight/day) or vehicle (normal saline) was given 24 h before NMDA or NMLA treatment and continued until the animals were sacrificed (varied from 1 to 7 days). Analyses of retinal ganglion cell (RGC) layer cell survival was performed on retinal flatmounts. Retinal cryostat sections were prepared for immunostaining, TUNEL assay and retinal thickness measurements. Fresh frozen retinal samples were used for Western blotting analysis. A marked decrease in the neuronal survival in the RGC layer was observed in NMDA treated retinas compared to their NMLA treated controls, as studied by NeuN immunostaining of retinal flatmounts. Treatment with MDL 72527 significantly improved survival of NeuN positive cells in the NMDA treated retinas. Excitotoxicity induced neurodegeneration was also demonstrated by reduced levels of synaptophysin and degeneration of inner retinal neurons in NMDA treated retinas compared to controls. TUNEL labeling studies showed increased cell death in the NMDA treated retinas. However, treatment with MDL 72527 markedly reduced these changes. Analysis of signaling pathways during excitotoxic injury revealed the downregulation of pro-survival signaling molecules p-ERK and p-Akt, and the upregulation of a pro-apoptotic molecule BID, which were normalized with PAO inhibition. Our data demonstrate that inhibition of polyamine oxidase blocks NMDA-induced retinal neurodegeneration and promotes cell survival, thus offering a new therapeutic target for retinal neurodegenerative disease conditions.
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Affiliation(s)
- Prahalathan Pichavaram
- Vision Discovery Institute, Augusta University, Augusta, GA, United States.,College of Allied Health Sciences, Augusta University, Augusta, GA, United States
| | - Chithra Devi Palani
- Vision Discovery Institute, Augusta University, Augusta, GA, United States.,Vascular Biology Center, Augusta University, Augusta, GA, United States.,Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, United States
| | - Chintan Patel
- Vision Discovery Institute, Augusta University, Augusta, GA, United States.,Vascular Biology Center, Augusta University, Augusta, GA, United States
| | - Zhimin Xu
- Vision Discovery Institute, Augusta University, Augusta, GA, United States.,Vascular Biology Center, Augusta University, Augusta, GA, United States
| | - Esraa Shosha
- Vision Discovery Institute, Augusta University, Augusta, GA, United States.,Vascular Biology Center, Augusta University, Augusta, GA, United States
| | - Abdelrahman Y Fouda
- Vision Discovery Institute, Augusta University, Augusta, GA, United States.,Vascular Biology Center, Augusta University, Augusta, GA, United States
| | - Ruth B Caldwell
- Vision Discovery Institute, Augusta University, Augusta, GA, United States.,Vascular Biology Center, Augusta University, Augusta, GA, United States.,VA Medical Center, Augusta, GA, United States
| | - Subhadra Priya Narayanan
- Vision Discovery Institute, Augusta University, Augusta, GA, United States.,College of Allied Health Sciences, Augusta University, Augusta, GA, United States.,Vascular Biology Center, Augusta University, Augusta, GA, United States.,Clinical and Experimental Therapeutics, College of Pharmacy, University of Georgia, Augusta, GA, United States.,VA Medical Center, Augusta, GA, United States
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Eriksen AZ, Eliasen R, Oswald J, Kempen PJ, Melander F, Andresen TL, Young M, Baranov P, Urquhart AJ. Multifarious Biologic Loaded Liposomes that Stimulate the Mammalian Target of Rapamycin Signaling Pathway Show Retina Neuroprotection after Retina Damage. ACS NANO 2018; 12:7497-7508. [PMID: 30004669 PMCID: PMC6117751 DOI: 10.1021/acsnano.8b00596] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
A common event in optic neuropathies is the loss of axons and death of retinal ganglion cells (RGCs) resulting in irreversible blindness. Mammalian target of rapamycin (mTOR) signaling pathway agonists have been shown to foster axon regeneration and RGC survival in animal models of optic nerve damage. However, many challenges remain in developing therapies that exploit cell growth and tissue remodeling including (i) activating/inhibiting cell pathways synergistically, (ii) avoiding tumorigenesis, and (iii) ensuring appropriate physiological tissue function. These challenges are further exacerbated by the need to overcome ocular physiological barriers and clearance mechanisms. Here we present liposomes loaded with multiple mTOR pathway stimulating biologics designed to enhance neuroprotection after retina damage. Liposomes were loaded with ciliary neurotrophic factor, insulin-like growth factor 1, a lipopeptide N-fragment osteopontin mimic, and lipopeptide phosphatase tension homologue inhibitors for either the ATP domain or the c-terminal tail. In a mouse model of N-methyl-d-aspartic acid induced RGC death, a single intravitreal administration of liposomes reduced both RGC death and loss of retina electrophysiological function. Furthermore, combining liposomes with transplantation of induced pluripotent stem cell derived RGCs led to an improved electrophysiological outcome in mice. The results presented here show that liposomes carrying multiple signaling pathway modulators can facilitate neuroprotection and transplant electrophysiological outcome.
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Affiliation(s)
- Anne Z. Eriksen
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Rasmus Eliasen
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Julia Oswald
- Schepens
Eye Research Institute, Massachusetts Eye and Ear, 20 Staniford Street, Boston, Massachusetts 02114, United States
| | - Paul J. Kempen
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Fredrik Melander
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Thomas L. Andresen
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
| | - Michael Young
- Schepens
Eye Research Institute, Massachusetts Eye and Ear, 20 Staniford Street, Boston, Massachusetts 02114, United States
| | - Petr Baranov
- Schepens
Eye Research Institute, Massachusetts Eye and Ear, 20 Staniford Street, Boston, Massachusetts 02114, United States
| | - Andrew J. Urquhart
- DTU
Nanotech, Department of Micro- and Nanotechnology, Technical University of Denmark, 2800 Kongens Lyngby, Denmark
- E-mail:
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Kuehn S, Rodust C, Stute G, Grotegut P, Meißner W, Reinehr S, Dick HB, Joachim SC. Concentration-Dependent Inner Retina Layer Damage and Optic Nerve Degeneration in a NMDA Model. J Mol Neurosci 2017; 63:283-299. [PMID: 28963708 DOI: 10.1007/s12031-017-0978-x] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 09/19/2017] [Indexed: 11/30/2022]
Abstract
The intravitreal injection of N-methyl-D-aspartate (NMDA), a glutamate analogue, is an established model for fast retinal ganglion cell (RGC) degeneration. Yet, NMDA does not cause specific RGC damage. Now, the effects on the whole retina were analyzed. Additionally, the related effects for the structure and apoptotic levels of the optic nerve were investigated. Therefore, different NMDA concentrations were intravitreally injected in rats (20, 40, or 80 nmol NMDA or PBS). At days 3 and 14, Brn-3a+ RGCs were degenerated. A damage of calretinin+ amacrine cells was also recognized at day 14. Only a slight damage was observed in regard to PKCα+ bipolar cells, while rhodopsin+ photoreceptors remained intact. A long-lasting retinal microglia response was observed from day 3 up to day 14. Furthermore, a partial degeneration of the optic nerve was noted. At day 3, the SMI-32+ neurofilaments were just slightly affected, whereas the neurofilament structure was further degenerated at day 14. However, the luxol fast blue (LFB)-stained myelin structure remained intact from day 3 up to day 14. Interestingly, apoptotic mechanisms, like FasL and Fas co-localization as well as caspase 3 activation, were restricted to the optic nerve of the highest NMDA group at this late stage of degeneration. The degeneration of the optic nerve is probably only a side effect of neuronal degeneration of the inner retinal layers. The intact myelin structure might form a barrier against the direct influence of NMDA. In conclusion, this model is very suitable to test therapeutic agents, but it is important to analyze all inner retina layers and the optic nerve to determine their efficacy in this model more precisely.
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Affiliation(s)
- Sandra Kuehn
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany
| | - Cara Rodust
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany
| | - Gesa Stute
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany
| | - Pia Grotegut
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany
| | - Wilhelm Meißner
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany
| | - Sabrina Reinehr
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany
| | - H Burkhard Dick
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany
| | - Stephanie C Joachim
- Experimental Eye Research Institute, University Eye Hospital, Ruhr-University Bochum, In der Schornau 23-25, 44892, Bochum, Germany.
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Downstream Regulatory Element Antagonist Modulator (DREAM), a target for anti-thrombotic agents. Pharmacol Res 2017; 117:283-287. [PMID: 28065857 DOI: 10.1016/j.phrs.2017.01.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/03/2017] [Indexed: 11/21/2022]
Abstract
Circulating platelets participate in the process of numerous diseases including thrombosis, inflammation, and cancer. Thus, it is of great importance to understand the underlying mechanisms mediating platelet activation under disease conditions. Emerging evidence indicates that despite the lack of a nucleus, platelets possess molecules that are involved in gene transcription in nucleated cells. This review will summarize downstream regulatory element antagonist modulator (DREAM), a transcriptional repressor, and highlight recent findings suggesting its novel non-transcriptional role in hemostasis and thrombosis.
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