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Subramani M, Lambrecht B, Ahmad I. Human microglia-derived proinflammatory cytokines facilitate human retinal ganglion cell development and regeneration. Stem Cell Reports 2024:S2213-6711(24)00189-9. [PMID: 39059376 DOI: 10.1016/j.stemcr.2024.06.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 06/21/2024] [Accepted: 06/23/2024] [Indexed: 07/28/2024] Open
Abstract
Microglia (μG), the resident immune cells in the central nervous system, surveil the parenchyma to maintain the structural and functional homeostasis of neurons. Besides, they influence neurogenesis and synaptogenesis through complement-mediated phagocytosis. Emerging evidence suggests that μG may also influence development through proinflammatory cytokines. Here, we examined the premise that tumor necrosis factor alpha (TNF-α) and interleukin-1β (IL-1β), the two most prominent components of the μG secretome, influence retinal development, specifically the morphological and functional differentiation of human retinal ganglion cells (hRGCs). Using controlled generation of hRGCs and human μG (hμG) from pluripotent stem cells, we demonstrate that TNF-α and IL-1β secreted by unchallenged hμG did not influence hRGC generation. However, their presence significantly facilitated neuritogenesis along with the basal function of hRGCs, which involved the recruitment of the AKT/mTOR pathway. We present ex vivo evidence that proinflammatory cytokines may play an important role in the morphological and physiological maturation of hRGCs, which may be recapitulated for regeneration.
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Affiliation(s)
- Murali Subramani
- Department of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE, USA
| | - Brandon Lambrecht
- Department of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE, USA
| | - Iqbal Ahmad
- Department of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE, USA.
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Kerkis I, da Silva ÁP, Araldi RP. The impact of interleukin-6 (IL-6) and mesenchymal stem cell-derived IL-6 on neurological conditions. Front Immunol 2024; 15:1400533. [PMID: 39015561 PMCID: PMC11249726 DOI: 10.3389/fimmu.2024.1400533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2024] [Accepted: 06/04/2024] [Indexed: 07/18/2024] Open
Abstract
Interleukin-6 (IL-6) is a versatile cytokine crucial for immune response modulation, inflammation regulation, and various physiological processes in the body. Its wide-ranging functions underscore its importance in maintaining health. Dysregulated IL-6 is closely associated with many diseases, making it a key research and therapeutic target. Elevated IL-6 levels in the central nervous system worsen neuroinflammation in neurodegenerative diseases by activating microglia and astrocytes and releasing pro-inflammatory cytokines and neurotoxic molecules. Moreover, dysregulated IL-6 weakens the blood-brain barrier, exacerbating neuroinflammation and neuronal damage by allowing peripheral immune cells and inflammatory mediators to enter the brain. Mesenchymal stem cells (MSCs) show promise in modulating neuroinflammation by regulating IL-6 levels. They effectively suppress pro-inflammatory cytokines, including IL-6, while promoting anti-inflammatory factors. This therapeutic approach highlights the importance of targeting IL-6 and other inflammatory mediators to alleviate neuroinflammation and its adverse effects on neurological disorders. This review provides a comprehensive overview of IL-6's involvement in neurological disorders, examining endogenous IL-6 and IL-6 derived from MSCs. We explore IL-6's mechanisms affecting neuronal function, survival, and immune modulation in the central nervous system. Additionally, we discuss the potential of MSC-derived IL-6 in neuroregeneration and neuroprotection. By elucidating IL-6's interplay with neurological pathologies, this review offers insights into novel therapeutic strategies targeting IL-6 signaling pathways for neurological disorders.
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Affiliation(s)
- Irina Kerkis
- Genetics Laboratory, Center of Development and Innovation, Butantan Institute, São Paulo, Brazil
| | - Álvaro Prieto da Silva
- Genetics Laboratory, Center of Development and Innovation, Butantan Institute, São Paulo, Brazil
| | - Rodrigo Pinheiro Araldi
- BioDecision Analytics Ltda., São Paulo, Brazil
- Post-graduation Program in Structural and Functional Biology, Paulista School of Medicine Escola Paulista de Medicina (EPM), Federal University of São Paulo Universidade Federal de São Paulo (UNIFESP), São Paulo, Brazil
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Zuo Z, Fan B, Zhang Z, Liang Y, Chi J, Li G. Interleukin-4 protects retinal ganglion cells and promotes axon regeneration. Cell Commun Signal 2024; 22:236. [PMID: 38650003 PMCID: PMC11034112 DOI: 10.1186/s12964-024-01604-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2024] [Accepted: 04/03/2024] [Indexed: 04/25/2024] Open
Abstract
BACKGROUND The preservation of retinal ganglion cells (RGCs) and the facilitation of axon regeneration are crucial considerations in the management of various vision-threatening disorders. Therefore, we investigate the efficacy of interleukin-4 (IL-4), a potential therapeutic agent, in promoting neuroprotection and axon regeneration of retinal ganglion cells (RGCs) as identified through whole transcriptome sequencing in an in vitro axon growth model. METHODS A low concentration of staurosporine (STS) was employed to induce in vitro axon growth. Whole transcriptome sequencing was utilized to identify key target factors involved in the molecular mechanism underlying axon growth. The efficacy of recombinant IL-4 protein on promoting RGC axon growth was validated through in vitro experiments. The protective effect of recombinant IL-4 protein on somas of RGCs was assessed using RBPMS-specific immunofluorescent staining in mouse models with optic nerve crush (ONC) and N-methyl-D-aspartic acid (NMDA) injury. The protective effect on RGC axons was evaluated by anterograde labeling of cholera toxin subunit B (CTB), while the promotion of RGC axon regeneration was assessed through both anterograde labeling of CTB and immunofluorescent staining for growth associated protein-43 (GAP43). RESULTS Whole-transcriptome sequencing of staurosporine-treated 661 W cells revealed a significant upregulation in intracellular IL-4 transcription levels during the process of axon regeneration. In vitro experiments demonstrated that recombinant IL-4 protein effectively stimulated axon outgrowth. Subsequent immunostaining with RBPMS revealed a significantly higher survival rate of RGCs in the rIL-4 group compared to the vehicle group in both NMDA and ONC injury models. Axonal tracing with CTB confirmed that recombinant IL-4 protein preserved long-distance projection of RGC axons, and there was a notably higher number of surviving axons in the rIL-4 group compared to the vehicle group following NMDA-induced injury. Moreover, intravitreal delivery of recombinant IL-4 protein substantially facilitated RGC axon regeneration after ONC injury. CONCLUSION The recombinant IL-4 protein exhibits the potential to enhance the survival rate of RGCs, protect RGC axons against NMDA-induced injury, and facilitate axon regeneration following ONC. This study provides an experimental foundation for further investigation and development of therapeutic agents aimed at protecting the optic nerve and promoting axon regeneration.
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Affiliation(s)
- Zhaoyang Zuo
- Department of Ophthalmology, The Second Norman Bethune Hospital of Jilin University, 130041, Changchun, China
| | - Bin Fan
- Department of Ophthalmology, The Second Norman Bethune Hospital of Jilin University, 130041, Changchun, China
| | - Ziyuan Zhang
- Department of Ophthalmology, The Second Norman Bethune Hospital of Jilin University, 130041, Changchun, China
| | - Yang Liang
- Department of Ophthalmology, The Second Norman Bethune Hospital of Jilin University, 130041, Changchun, China
| | - Jing Chi
- Department of Ophthalmology, The Second Norman Bethune Hospital of Jilin University, 130041, Changchun, China
| | - Guangyu Li
- Department of Ophthalmology, The Second Norman Bethune Hospital of Jilin University, 130041, Changchun, China.
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Norte-Muñoz M, García-Bernal D, García-Ayuso D, Vidal-Sanz M, Agudo-Barriuso M. Interplay between mesenchymal stromal cells and the immune system after transplantation: implications for advanced cell therapy in the retina. Neural Regen Res 2024; 19:542-547. [PMID: 37721282 PMCID: PMC10581591 DOI: 10.4103/1673-5374.380876] [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: 02/28/2023] [Revised: 03/25/2023] [Accepted: 05/11/2023] [Indexed: 09/19/2023] Open
Abstract
Advanced mesenchymal stromal cell-based therapies for neurodegenerative diseases are widely investigated in preclinical models. Mesenchymal stromal cells are well positioned as therapeutics because they address the underlying mechanisms of neurodegeneration, namely trophic factor deprivation and neuroinflammation. Most studies have focused on the beneficial effects of mesenchymal stromal cell transplantation on neuronal survival or functional improvement. However, little attention has been paid to the interaction between mesenchymal stromal cells and the host immune system due to the immunomodulatory properties of mesenchymal stromal cells and the long-held belief of the immunoprivileged status of the central nervous system. Here, we review the crosstalk between mesenchymal stromal cells and the immune system in general and in the context of the central nervous system, focusing on recent work in the retina and the importance of the type of transplantation.
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Affiliation(s)
- María Norte-Muñoz
- Grupo de Investigación Oftalmología Experimental, Departamento de Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica, Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria (IMIB), Campus de Ciencias de la Salud, 30120 Murcia, Spain
| | - David García-Bernal
- Grupo de Investigación Trasplante Hematopoyético y Terapia celular, Departamento de Bioquímica e Inmunología. Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria (IMIB), Campus de Ciencias de la Salud, 30120 Murcia, Spain
| | - Diego García-Ayuso
- Grupo de Investigación Oftalmología Experimental, Departamento de Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica, Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria (IMIB), Campus de Ciencias de la Salud, 30120 Murcia, Spain
| | - Manuel Vidal-Sanz
- Grupo de Investigación Oftalmología Experimental, Departamento de Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica, Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria (IMIB), Campus de Ciencias de la Salud, 30120 Murcia, Spain
| | - Marta Agudo-Barriuso
- Grupo de Investigación Oftalmología Experimental, Departamento de Oftalmología, Optometría, Otorrinolaringología y Anatomía Patológica, Facultad de Medicina, Universidad de Murcia, Instituto Murciano de Investigación Biosanitaria (IMIB), Campus de Ciencias de la Salud, 30120 Murcia, Spain
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Leibinger M, Zeitler C, Paulat M, Gobrecht P, Hilla A, Andreadaki A, Guthoff R, Fischer D. Inhibition of microtubule detyrosination by parthenolide facilitates functional CNS axon regeneration. eLife 2023; 12:RP88279. [PMID: 37846146 PMCID: PMC10581688 DOI: 10.7554/elife.88279] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2023] Open
Abstract
Injured axons in the central nervous system (CNS) usually fail to regenerate, causing permanent disabilities. However, the knockdown of Pten knockout or treatment of neurons with hyper-IL-6 (hIL-6) transforms neurons into a regenerative state, allowing them to regenerate axons in the injured optic nerve and spinal cord. Transneuronal delivery of hIL-6 to the injured brain stem neurons enables functional recovery after severe spinal cord injury. Here we demonstrate that the beneficial hIL-6 and Pten knockout effects on axon growth are limited by the induction of tubulin detyrosination in axonal growth cones. Hence, cotreatment with parthenolide, a compound blocking microtubule detyrosination, synergistically accelerates neurite growth of cultured murine CNS neurons and primary RGCs isolated from adult human eyes. Systemic application of the prodrug dimethylamino-parthenolide (DMAPT) facilitates axon regeneration in the injured optic nerve and spinal cord. Moreover, combinatorial treatment further improves hIL-6-induced axon regeneration and locomotor recovery after severe SCI. Thus, DMAPT facilitates functional CNS regeneration and reduces the limiting effects of pro-regenerative treatments, making it a promising drug candidate for treating CNS injuries.
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Affiliation(s)
- Marco Leibinger
- Center for Pharmacology, Institute II, Medical Faculty and University of CologneCologneGermany
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
| | - Charlotte Zeitler
- Center for Pharmacology, Institute II, Medical Faculty and University of CologneCologneGermany
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
| | - Miriam Paulat
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
| | - Philipp Gobrecht
- Center for Pharmacology, Institute II, Medical Faculty and University of CologneCologneGermany
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
| | - Alexander Hilla
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
| | - Anastasia Andreadaki
- Center for Pharmacology, Institute II, Medical Faculty and University of CologneCologneGermany
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
| | - Rainer Guthoff
- Eye Hospital, Heinrich Heine University DüsseldorfDüsseldorfGermany
| | - Dietmar Fischer
- Center for Pharmacology, Institute II, Medical Faculty and University of CologneCologneGermany
- Department of Cell Physiology, Ruhr University of BochumBochumGermany
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Liu W, Zhu X, Ge X, Chen Y, Li DWC, Gong L. Light damage induces inflammatory factors in mouse retina and vitreous humor. Mol Vis 2023; 29:180-187. [PMID: 38222454 PMCID: PMC10784230] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Accepted: 10/10/2023] [Indexed: 01/16/2024] Open
Abstract
Purpose Increased inflammatory factor levels have been reported in the vitreous humor (VH) of diabetic retinopathy and neovascular age-related macular degeneration, ocular diseases generally associated with the formation of new retinal blood vessels and leakage. However, the levels of inflammatory mediators are less known in retinal degeneration without neovascularization. Human retinitis pigmentosa (RP) and animal models of light-induced retinal degeneration (LIRD) share several features, such as photoreceptor death and retinal inflammation. Here, we aimed to determine the levels of inflammatory factors in the VH of the LIRD mouse model. Methods LIRD was induced by exposing BALB/c mice to white light (15,000 lx, 2 h), and the mice were recovered for 2 days before analysis (n = 50 mice). We assessed retinal morphology using optical coherence tomography and hematoxylin and eosin staining; retinal cell viability was determined using terminal deoxynucleotidyl transferase dUTP nick-end labeling, and retinal responses were measured based on electroretinogram signals. Total retinal RNAs were extracted and subjected to RNA sequencing analysis. VH samples from control (n = 4) and LIRD mice (n = 9) were assayed in triplicate for a panel of four inflammatory mediators using the Simple Plex Cartridge on an Ella System. Results Retinal degeneration, photoreceptor death, infiltration of microglia/macrophages into the photoreceptor layer, and loss of a- and b-waves were obviously detected after LIRD. RNA sequencing revealed that light damage (LD) led to the significant upregulation of inflammatory factors in mouse retinas. In the VH, LD increased the total protein concentration. Dramatic induction of CCL2 (~3000 fold) and IL6 (~10 fold) was detected in VH in response to LD. Increased but not significant levels of TNFα and IL1β were also detected in light-exposed VH. Conclusions Given that the LIRD model mimics RP pathogenesis in some aspects, these results suggest a causative link between retinal degeneration and VH inflammation in RP progression, and the increased CCL2 level in VH may reflect similar elevated CCL2 expression in the degenerative retina.
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Affiliation(s)
- Wei Liu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, 510060, China
| | - Xingfei Zhu
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, 510060, China
| | - Xiangyu Ge
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, 510060, China
| | - Yulin Chen
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, 510060, China
| | - David Wan-Cheng Li
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, 510060, China
| | - Lili Gong
- State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-Sen University, Guangzhou, Guangdong, 510060, China
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Zhang ZY, Zuo ZY, Liang Y, Zhang SM, Zhang CX, Chi J, Fan B, Li GY. Promotion of axon regeneration and protection on injured retinal ganglion cells by rCXCL2. Inflamm Regen 2023; 43:31. [PMID: 37340465 DOI: 10.1186/s41232-023-00283-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 05/31/2023] [Indexed: 06/22/2023] Open
Abstract
BACKGROUND In addition to rescuing injured retinal ganglion cells (RGCs) by stimulating the intrinsic growth ability of damaged RGCs in various retinal/optic neuropathies, increasing evidence has shown that the external microenvironmental factors also play a crucial role in restoring the survival of RGCs by promoting the regrowth of RGC axons, especially inflammatory factors. In this study, we aimed to screen out the underlying inflammatory factor involved in the signaling of staurosporine (STS)-induced axon regeneration and verify its role in the protection of RGCs and the promotion of axon regrowth. METHODS We performed transcriptome RNA sequencing for STS induction models in vitro and analyzed the differentially expressed genes. After targeting the key gene, we verified the role of the candidate factor in RGC protection and promotion of axon regeneration in vivo with two RGC-injured animal models (optic nerve crush, ONC; retinal N-methyl-D-aspartate, NMDA damage) by using cholera toxin subunit B anterograde axon tracing and specific immunostaining of RGCs. RESULTS We found that a series of inflammatory genes expressed upregulated in the signaling of STS-induced axon regrowth and we targeted the candidate CXCL2 gene since the level of the chemokine CXCL2 gene elevated significantly among the top upregulated genes. We further demonstrated that intravitreal injection of rCXCL2 robustly promoted axon regeneration and significantly improved RGC survival in ONC-injured mice in vivo. However, different from its role in ONC model, the intravitreal injection of rCXCL2 was able to simply protect RGCs against NMDA-induced excitotoxicity in mouse retina and maintain the long-distance projection of RGC axons, yet failed to promote significant axon regeneration. CONCLUSIONS We provide the first in vivo evidence that CXCL2, as an inflammatory factor, is a key regulator in the axon regeneration and neuroprotection of RGCs. Our comparative study may facilitate deciphering the exact molecular mechanisms of RGC axon regeneration and developing high-potency targeted drugs.
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Affiliation(s)
- Zi-Yuan Zhang
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, 130041, China
| | - Zhao-Yang Zuo
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, 130041, China
| | - Yang Liang
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, 130041, China
| | - Si-Ming Zhang
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, 130041, China
| | - Chun-Xia Zhang
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, 130041, China
| | - Jing Chi
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, 130041, China
| | - Bin Fan
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, 130041, China.
| | - Guang-Yu Li
- Department of Ophthalmology, Second Hospital of Jilin University, Changchun, 130041, China.
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Ulhaq ZS, Istifiani LA, Pamungkas SA. Evaluation of systemic IL-6 trans-signalling in patients with primary open-angle glaucoma. J Fr Ophtalmol 2023:S0181-5512(23)00143-2. [PMID: 37095023 DOI: 10.1016/j.jfo.2022.11.022] [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: 09/08/2022] [Revised: 10/29/2022] [Accepted: 11/11/2022] [Indexed: 04/26/2023]
Abstract
PURPOSE To evaluate systemic trans-signalling of interleukin (IL)-6 in patients with primary open-angle glaucoma (POAG). METHODS Fifty-one POAG patients and 47 matched healthy controls were enrolled. Serum concentrations of IL-6, sIL-6R, and sgp130 were quantified. RESULTS Serum levels of IL-6, sIL-6R, and IL-6/sIL-6R ratios in the POAG group were significantly higher than those in control group, while only the sgp130/sIL-6R/IL-6 ratio was decreased. Among POAG subjects, advanced-stage patients exhibited significantly higher intraocular pressure (IOP), serum IL-6 and sgp130 levels, and IL-6/sIL-6R ratio than those in the early to moderate stage. The ROC curve analysis revealed that the IL-6 level and IL-6/sIL-6R ratio performed better than other parameters in diagnosing POAG and discriminating POAG severity. Serum IL-6 level was moderately correlated with IOP and C/D ratio, while a weak correlation was observed between sIL-6R levels with C/D ratio. IL-6 and sIL-6R levels were correlated with each other in POAG patients but not in healthy controls. CONCLUSION Overstimulation of systemic IL-6 trans-signalling has been implicated in POAG.
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Affiliation(s)
- Z S Ulhaq
- Research Center for Pre-Clinical and Clinical Medicine, National Research and Innovation Agency Republic of Indonesia, Cibinong, Indonesia; Laboratory of Developmental Disorders and Toxicology, Center for Promotion of International Education and Research, Kyushu University, Fukuoka, Japan.
| | - L A Istifiani
- Department of Nutrition, Faculty of Health Sciences, Brawijaya University, Malang, Indonesia
| | - S A Pamungkas
- Al-Falah Social Fund Foundation Clinic (YDSF), Malang, Indonesia
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Axonal Regeneration: Underlying Molecular Mechanisms and Potential Therapeutic Targets. Biomedicines 2022; 10:biomedicines10123186. [PMID: 36551942 PMCID: PMC9775075 DOI: 10.3390/biomedicines10123186] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 11/21/2022] [Accepted: 12/01/2022] [Indexed: 12/13/2022] Open
Abstract
Axons in the peripheral nervous system have the ability to repair themselves after damage, whereas axons in the central nervous system are unable to do so. A common and important characteristic of damage to the spinal cord, brain, and peripheral nerves is the disruption of axonal regrowth. Interestingly, intrinsic growth factors play a significant role in the axonal regeneration of injured nerves. Various factors such as proteomic profile, microtubule stability, ribosomal location, and signalling pathways mark a line between the central and peripheral axons' capacity for self-renewal. Unfortunately, glial scar development, myelin-associated inhibitor molecules, lack of neurotrophic factors, and inflammatory reactions are among the factors that restrict axonal regeneration. Molecular pathways such as cAMP, MAPK, JAK/STAT, ATF3/CREB, BMP/SMAD, AKT/mTORC1/p70S6K, PI3K/AKT, GSK-3β/CLASP, BDNF/Trk, Ras/ERK, integrin/FAK, RhoA/ROCK/LIMK, and POSTN/integrin are activated after nerve injury and are considered significant players in axonal regeneration. In addition to the aforementioned pathways, growth factors, microRNAs, and astrocytes are also commendable participants in regeneration. In this review, we discuss the detailed mechanism of each pathway along with key players that can be potentially valuable targets to help achieve quick axonal healing. We also identify the prospective targets that could help close knowledge gaps in the molecular pathways underlying regeneration and shed light on the creation of more powerful strategies to encourage axonal regeneration after nervous system injury.
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Chronic Chemogenetic Activation of the Superior Colliculus in Glaucomatous Mice: Local and Retrograde Molecular Signature. Cells 2022; 11:cells11111784. [PMID: 35681479 PMCID: PMC9179903 DOI: 10.3390/cells11111784] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2022] [Revised: 05/20/2022] [Accepted: 05/22/2022] [Indexed: 12/13/2022] Open
Abstract
One important facet of glaucoma pathophysiology is axonal damage, which ultimately disrupts the connection between the retina and its postsynaptic brain targets. The concurrent loss of retrograde support interferes with the functionality and survival of the retinal ganglion cells (RGCs). Previous research has shown that stimulation of neuronal activity in a primary retinal target area—i.e., the superior colliculus—promotes RGC survival in an acute mouse model of glaucoma. To build further on this observation, we applied repeated chemogenetics in the superior colliculus of a more chronic murine glaucoma model—i.e., the microbead occlusion model—and performed bulk RNA sequencing on collicular lysates and isolated RGCs. Our study revealed that chronic target stimulation upon glaucomatous injury phenocopies the a priori expected molecular response: growth factors were pinpointed as essential transcriptional regulators both in the locally stimulated tissue and in distant, unstimulated RGCs. Strikingly, and although the RGC transcriptome revealed a partial reversal of the glaucomatous signature and an enrichment of pro-survival signaling pathways, functional rescue of injured RGCs was not achieved. By postulating various explanations for the lack of RGC neuroprotection, we aim to warrant researchers and drug developers for the complexity of chronic neuromodulation and growth factor signaling.
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Guo TT, Zhao Y, Huang WX, Zhang T, Zhao LL, Gu XS, Zhou SL. Silencing the enhancer of zeste homologue 2, Ezh2, represses axon regeneration of dorsal root ganglion neurons. Neural Regen Res 2021; 17:1518-1525. [PMID: 34916437 PMCID: PMC8771100 DOI: 10.4103/1673-5374.330623] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Recovery from injury to the peripheral nervous system is different from that of the central nervous system in that it can lead to gene reprogramming that can induce the expression of a series of regeneration-associated genes. This eventually leads to axonal regeneration of injured neurons. Although some regeneration-related genes have been identified, the regulatory network underlying axon regeneration remains largely unknown. To explore the regulator of axon regeneration, we performed RNA sequencing of lumbar L4 and L5 dorsal root ganglion (DRG) neurons at different time points (0, 3, 6, 12 hours, 1, 3 and 7 days) after rat sciatic nerve crush. The isolation of neurons was carried out by laser capture microscopy combined with NeuN immunofluorescence staining. We found 1228 differentially expressed genes in the injured sciatic nerve tissue. The hub genes within these differentially expressed genes include Atf3, Jun, Myc, Ngf, Fgf2, Ezh2, Gfap and Il6. We verified that the expression of the enhancer of zeste homologue 2 gene (Ezh2) was up-regulated in DRG neurons after injury, and this up-regulation differed between large- and small-sized dorsal root ganglion neurons. To investigate whether the up-regulation of Ezh2 impacts axonal regeneration, we silenced Ezh2 with siRNA in cultured DRG neurons and found that the growth of the newborn axons was repressed. In our investigation into the regulatory network of Ezh2 by interpretive phenomenal analysis, we found some regulators of Ezh2 (including Erk, Il6 and Hif1a) and targets (including Atf3, Cdkn1a and Smad1). Our findings suggest that Ezh2, as a nerve regeneration-related gene, participates in the repair of the injured DRG neurons, and knocking down the Ezh2 in vitro inhibits the axonal growth of DRG neurons. All the experimental procedures approved by the Administration Committee of Experimental Animals of Jiangsu Province of China (approval No. S20191201-201) on March 21, 2019.
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Affiliation(s)
- Ting-Ting Guo
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Ying Zhao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Wei-Xiao Huang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Tao Zhang
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Li-Li Zhao
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong; Model Animal Research Center and MOE Key Laboratory of Animal Models of Disease, Nanjing University, Nanjing, Jiangsu Province, China
| | - Xiao-Song Gu
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
| | - Song-Lin Zhou
- Key Laboratory of Neuroregeneration of Jiangsu and Ministry of Education, NMPA Key Laboratory for Research and Evaluation of Tissue Engineering Technology Products, Jiangsu Clinical Medicine Center of Tissue Engineering and Nerve Injury Repair, Co-Innovation Center of Neuroregeneration, Nantong University, Nantong, Jiangsu Province, China
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12
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Dong J, Viswanathan S, Adami E, Schafer S, Kuthubudeen FF, Widjaja AA, Cook SA. The pro-regenerative effects of hyperIL6 in drug-induced liver injury are unexpectedly due to competitive inhibition of IL11 signaling. eLife 2021; 10:68843. [PMID: 34435951 PMCID: PMC8445623 DOI: 10.7554/elife.68843] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Accepted: 08/24/2021] [Indexed: 01/20/2023] Open
Abstract
It is generally accepted that IL6-mediated STAT3 signaling in hepatocytes, mediated via glycoprotein 130 (gp130; IL6ST), is beneficial and that the synthetic IL6:IL6ST fusion protein (HyperIL6) promotes liver regeneration. Recently, autocrine IL11 activity that also acts via IL6ST but uses ERK rather than STAT3 to signal, was found to be hepatotoxic. Here we examined whether the beneficial effects of HyperIL6 could reflect unappreciated competitive inhibition of IL11-dependent IL6ST signaling. In human and mouse hepatocytes, HyperIL6 reduced N-acetyl-p-aminophenol (APAP)-induced cell death independent of STAT3 activation and instead, dose-dependently, inhibited IL11-related signaling and toxicities. In mice, expression of HyperIl6 reduced ERK activation and promoted STAT3-independent hepatic regeneration (PCNA, Cyclin D1, Ki67) following administration of either IL11 or APAP. Inhibition of putative intrinsic IL6 trans-signaling had no effect on liver regeneration in mice. Following APAP, mice deleted for Il11 exhibited spontaneous liver repair but HyperIl6, despite robustly activating STAT3, had no effect on liver regeneration in this strain. These data show that synthetic IL6ST binding proteins such as HyperIL6 can have unexpected, on-target effects and suggest IL11, not IL6, as important for liver regeneration.
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Affiliation(s)
- Jinrui Dong
- Cardiovascular and Metabolic Disorders Program, Duke-National University ofSingapore Medical School, Singapore, Singapore
| | - Sivakumar Viswanathan
- Cardiovascular and Metabolic Disorders Program, Duke-National University ofSingapore Medical School, Singapore, Singapore
| | - Eleonora Adami
- Cardiovascular and Metabolic Disorders Program, Duke-National University ofSingapore Medical School, Singapore, Singapore
| | - Sebastian Schafer
- Cardiovascular and Metabolic Disorders Program, Duke-National University ofSingapore Medical School, Singapore, Singapore
| | - Fathima F Kuthubudeen
- Cardiovascular and Metabolic Disorders Program, Duke-National University ofSingapore Medical School, Singapore, Singapore
| | - Anissa A Widjaja
- Cardiovascular and Metabolic Disorders Program, Duke-National University ofSingapore Medical School, Singapore, Singapore
| | - Stuart A Cook
- Cardiovascular and Metabolic Disorders Program, Duke-National University ofSingapore Medical School, Singapore, Singapore.,National Heart Research Institute Singapore, National Heart Centre Singapore, Singapore, Singapore.,MRC-London Institute of Medical Sciences, Hammersmith Hospital Campus, London, United Kingdom
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13
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Suggestive evidence of genetic association of -572G > C polymorphism with primary open angle glaucoma in a North Indian Punjabi population. Hum Immunol 2021; 82:791-797. [PMID: 34301420 DOI: 10.1016/j.humimm.2021.06.009] [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: 12/23/2020] [Revised: 05/09/2021] [Accepted: 06/23/2021] [Indexed: 11/21/2022]
Abstract
BACKGROUND IL6 is an important candidate gene implicated in the pathogenesis of glaucoma. The present study assessed the genetic association of -174G > C and -572G > C polymorphisms in the IL6 promoter region with primary open angle glaucoma (POAG) and primary angle closure glaucoma (PACG) in a north Indian Punjabi cohort. METHODS 910 subjects (313 POAG, 148 PACG cases and 449 controls) were recruited. Genotyping was done by TaqMan assays. Genetic association was tested under different genetic models using Plink. Diplotype and linkage disequilibrium (LD) analysis was done through Haploview. Association of clinical parameters with the genotypes was assessed by one-way ANOVA. Adjustment for potential confounding variables was done by binary logistic regression. IL6 levels were measured in POAG patients and controls. RESULTS 572G > C variant showed marginal difference in genotype frequency between pooled cases and POAG subgroup with respect to controls (p = 0.042; OR = 1.33; and p = 0.041; OR = 1.37). The GC genotype conferred 1.37-fold protection under codominant model in POAG cases (p = 0.034, OR = 1.37, 95% CI = 1.02-1.85; pcorr = 0.025, OR = 1.45, 95% CI = 1.04-2.02). The mean value for IOP was elevated among cases having 'CC' genotype at the -572G > C locus (p = 0.037). Lower levels of IL6 were detected in POAG patients in plasma samples (p = 0.0001). CONCLUSION The study reports suggestive evidence for -572G > C variant in IL6 in affecting genetic susceptibility to POAG in the targeted North Indian Punjabi cohort. A correlation of IL6 levels in aqueous humor (AH) and systemic circulation in POAG was observed, the functional and diagnostic relevance of which may be further investigated.
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14
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MMP2 Modulates Inflammatory Response during Axonal Regeneration in the Murine Visual System. Cells 2021; 10:cells10071672. [PMID: 34359839 PMCID: PMC8307586 DOI: 10.3390/cells10071672] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 06/21/2021] [Accepted: 06/26/2021] [Indexed: 12/17/2022] Open
Abstract
Neuroinflammation has been put forward as a mechanism triggering axonal regrowth in the mammalian central nervous system (CNS), yet little is known about the underlying cellular and molecular players connecting these two processes. In this study, we provide evidence that MMP2 is an essential factor linking inflammation to axonal regeneration by using an in vivo mouse model of inflammation-induced axonal regeneration in the optic nerve. We show that infiltrating myeloid cells abundantly express MMP2 and that MMP2 deficiency results in reduced long-distance axonal regeneration. However, this phenotype can be rescued by restoring MMP2 expression in myeloid cells via a heterologous bone marrow transplantation. Furthermore, while MMP2 deficiency does not affect the number of infiltrating myeloid cells, it does determine the coordinated expression of pro- and anti-inflammatory molecules. Altogether, in addition to its role in axonal regeneration via resolution of the glial scar, here, we reveal a new mechanism via which MMP2 facilitates axonal regeneration, namely orchestrating the expression of pro- and anti-inflammatory molecules by infiltrating innate immune cells.
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15
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Oshitari T. Understanding intrinsic survival and regenerative pathways through in vivo and in vitro studies: implications for optic nerve regeneration. EXPERT REVIEW OF OPHTHALMOLOGY 2021. [DOI: 10.1080/17469899.2021.1912595] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Affiliation(s)
- Toshiyuki Oshitari
- Department of Ophthalmology and Visual Science, Chiba University Graduate School of Medicine, Japan
- Department of Ophthalmology, International University of Health and Welfare School of Medicine, Narita, Japan
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16
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Transneuronal delivery of hyper-interleukin-6 enables functional recovery after severe spinal cord injury in mice. Nat Commun 2021; 12:391. [PMID: 33452250 PMCID: PMC7810685 DOI: 10.1038/s41467-020-20112-4] [Citation(s) in RCA: 60] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 11/13/2020] [Indexed: 12/27/2022] Open
Abstract
Spinal cord injury (SCI) often causes severe and permanent disabilities due to the regenerative failure of severed axons. Here we report significant locomotor recovery of both hindlimbs after a complete spinal cord crush. This is achieved by the unilateral transduction of cortical motoneurons with an AAV expressing hyper-IL-6 (hIL-6), a potent designer cytokine stimulating JAK/STAT3 signaling and axon regeneration. We find collaterals of these AAV-transduced motoneurons projecting to serotonergic neurons in both sides of the raphe nuclei. Hence, the transduction of cortical neurons facilitates the axonal transport and release of hIL-6 at innervated neurons in the brain stem. Therefore, this transneuronal delivery of hIL-6 promotes the regeneration of corticospinal and raphespinal fibers after injury, with the latter being essential for hIL-6-induced functional recovery. Thus, transneuronal delivery enables regenerative stimulation of neurons in the deep brain stem that are otherwise challenging to access, yet highly relevant for functional recovery after SCI.
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17
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Neural Cadherin Plays Distinct Roles for Neuronal Survival and Axon Growth under Different Regenerative Conditions. eNeuro 2020; 7:ENEURO.0325-20.2020. [PMID: 32967889 PMCID: PMC7688304 DOI: 10.1523/eneuro.0325-20.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 08/26/2020] [Accepted: 08/28/2020] [Indexed: 12/18/2022] Open
Abstract
Growing axons in the CNS often migrate along specific pathways to reach their targets. During embryonic development, this migration is guided by different types of cell adhesion molecules (CAMs) present on the surface of glial cells or other neurons, including the neural cadherin (NCAD). Axons in the adult CNS can be stimulated to regenerate, and travel long distances. Crucially, however, while a few axons are guided effectively through the injured nerve under certain conditions, most axons never migrate properly. The molecular underpinnings of the variable growth, and the glial CAMs that are responsible for CNS axon regeneration remain unclear. Here we used optic nerve crush to demonstrate that NCAD plays multifaceted functions in facilitating CNS axon regeneration. Astrocyte-specific deletion of NCAD dramatically decreases regeneration induced by phosphatase and tensin homolog (PTEN) ablation in retinal ganglion cells (RGCs). Consistent with NCAD’s tendency to act as homodimers, deletion of NCAD in RGCs also reduces regeneration. Deletion of NCAD in astrocytes neither alters RGCs’ mammalian target of rapamycin complex 1 (mTORC1) activity nor lesion size, two factors known to affect regeneration. Unexpectedly, however, we find that NCAD deletion in RGCs reduces PTEN-deletion-induced RGC survival. We further show that NCAD deletion, in either astrocytes or RGCs, has negligible effects on the regeneration induced by ciliary neurotrophic factor (CNTF), suggesting that other CAMs are critical under this regenerative condition. Consistent with this notion, CNTF induces expression various integrins known to mediate cell adhesion. Together, our study reveals multilayered functions of NCAD and a molecular basis of variability in guided axon growth.
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Teotia P, Van Hook MJ, Fischer D, Ahmad I. Human retinal ganglion cell axon regeneration by recapitulating developmental mechanisms: effects of recruitment of the mTOR pathway. Development 2019; 146:dev178012. [PMID: 31273087 PMCID: PMC6633601 DOI: 10.1242/dev.178012] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 05/15/2019] [Indexed: 12/15/2022]
Abstract
The poor axon regeneration in the central nervous system (CNS) often leads to permanent functional deficit following disease or injury. For example, degeneration of retinal ganglion cell (RGC) axons in glaucoma leads to irreversible loss of vision. Here, we have tested the hypothesis that the mTOR pathway regulates the development of human RGCs and that its recruitment after injury facilitates axon regeneration. We observed that the mTOR pathway is active during RGC differentiation, and using the induced pluripotent stem cell model of neurogenesis show that it facilitates the differentiation, function and neuritogenesis of human RGCs. Using a microfluidic model, we demonstrate that recruitment of the mTOR pathway facilitates human RGC axon regeneration after axotomy, providing evidence that the recapitulation of developmental mechanism(s) might be a viable approach for facilitating axon regeneration in the diseased or injured human CNS, thus helping to reduce and/or recover loss of function.
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Affiliation(s)
- Pooja Teotia
- Department of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Matthew J Van Hook
- Department of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Dietmar Fischer
- Department of Cell Physiology, Ruhr University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
- Division of Experimental Neurology, Medical Faculty, Heinrich Heine University, Merowingerplatz 1a, 40225 Düsseldorf, Germany
| | - Iqbal Ahmad
- Department of Ophthalmology and Visual Science, University of Nebraska Medical Center, Omaha, NE 68198, USA
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19
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Menezes GD, Faria-Melibeu AC, Serfaty CA, Campello-Costa P. In vivo effect of acute exposure to interleukin-6 on the developing visual system. Neurosci Lett 2019; 698:7-12. [PMID: 30611891 DOI: 10.1016/j.neulet.2019.01.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2018] [Revised: 12/10/2018] [Accepted: 01/02/2019] [Indexed: 01/12/2023]
Abstract
Interleukin-6 (IL-6) is involved in different processes of the central nervous system. Our aims were to investigate the effect of IL-6 on retinotectal topography and on different signaling pathways. Rats were submitted to an intravitreous injection of either IL-6 (50 ng/ml) or PBS (vehicle) at postnatal day 10 (PND10). At PND11 or PND14, different groups were processed for western blot, histochemistry or immunofluorescence analysis. IL-6 treatment leads to an increase in pSTAT-3 levels in the retina and a disruption in the retinotectal topographic map, suggesting that a transient increase in interleukin-6 levels may impact neural circuitry development.
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Affiliation(s)
- Grasielle Duarte Menezes
- Programa de Neurociências, Departamento de Neurobiologia, Universidade Federal Fluminense, Niterói, RJ, Brazil.
| | - Adriana C Faria-Melibeu
- Programa de Neurociências, Departamento de Neurobiologia, Universidade Federal Fluminense, Niterói, RJ, Brazil.
| | - Claudio Alberto Serfaty
- Programa de Neurociências, Departamento de Neurobiologia, Universidade Federal Fluminense, Niterói, RJ, Brazil.
| | - Paula Campello-Costa
- Programa de Neurociências, Departamento de Neurobiologia, Universidade Federal Fluminense, Niterói, RJ, Brazil.
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20
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Li S, Sato K, Gordon WC, Sendtner M, Bazan NG, Jin M. Ciliary neurotrophic factor (CNTF) protects retinal cone and rod photoreceptors by suppressing excessive formation of the visual pigments. J Biol Chem 2018; 293:15256-15268. [PMID: 30115683 DOI: 10.1074/jbc.ra118.004008] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Revised: 08/15/2018] [Indexed: 12/25/2022] Open
Abstract
The retinal pigment epithelium (RPE)-dependent visual cycle provides 11-cis-retinal to opsins in the photoreceptor outer segments to generate functional visual pigments that initiate phototransduction in response to light stimuli. Both RPE65 isomerase of the visual cycle and the rhodopsin visual pigment have recently been identified as critical players in mediating light-induced retinal degeneration. These findings suggest that the expression and function of RPE65 and rhodopsin need to be coordinately controlled to sustain normal vision and to protect the retina from photodamage. However, the mechanism controlling the development of the retinal visual system remains poorly understood. Here, we show that deficiency in ciliary neurotrophic factor (CNTF) up-regulates the levels of rod and cone opsins accompanied by an increase in the thickness of the outer nuclear layers and the lengths of cone and rod outer segments in the mouse retina. Moreover, retinoid isomerase activity, expression levels of RPE65 and lecithin:retinol acyltransferase (LRAT), which synthesizes the RPE65 substrate, were also significantly increased in the Cntf -/- RPE. Rod a-wave and cone b-wave amplitudes of electroretinograms were increased in Cntf -/- mice, but rod b-wave amplitudes were unchanged compared with those in WT mice. Up-regulated RPE65 and LRAT levels accelerated both the visual cycle rate and recovery rate of rod light sensitivity in Cntf -/- mice. Of note, rods and cones in Cntf -/- mice exhibited hypersusceptibility to light-induced degeneration. These results indicate that CNTF is a common extracellular factor that prevents excessive production of opsins, the photoreceptor outer segments, and 11-cis-retinal to protect rods and cones from photodamage.
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Affiliation(s)
- Songhua Li
- From the Neuroscience Center of Excellence and
| | - Kota Sato
- From the Neuroscience Center of Excellence and
| | - William C Gordon
- From the Neuroscience Center of Excellence and.,Department of Ophthalmology, Louisiana State University School of Medicine, New Orleans, Louisiana 70112 and
| | - Michael Sendtner
- the Institute of Clinical Neurobiology, University Hospital Würzburg, D-97078 Würzburg, Germany
| | - Nicolas G Bazan
- From the Neuroscience Center of Excellence and.,Department of Ophthalmology, Louisiana State University School of Medicine, New Orleans, Louisiana 70112 and
| | - Minghao Jin
- From the Neuroscience Center of Excellence and .,Department of Ophthalmology, Louisiana State University School of Medicine, New Orleans, Louisiana 70112 and
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21
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Levin E, Diekmann H, Fischer D. Highly efficient transduction of primary adult CNS and PNS neurons. Sci Rep 2016; 6:38928. [PMID: 27958330 PMCID: PMC5153636 DOI: 10.1038/srep38928] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 11/15/2016] [Indexed: 12/19/2022] Open
Abstract
Delivery and expression of recombinant genes, a key methodology for many applications in biological research, remains a challenge especially for mature neurons. Here, we report easy, highly efficient and well tolerated transduction of adult peripheral and central neuronal populations of diverse species in culture using VSV-G pseudo-typed, recombinant baculovirus (BacMam). Transduction rates of up to 80% were reliably achieved at high multiplicity of infection without apparent neuro-cytopathic effects. Neurons could be transduced either shortly after plating or after several days in culture. Co-incubation with two different baculoviruses attained near complete co-localization of fluorescent protein expression, indicating multigene delivery. Finally, evidence for functional protein expression is provided by means of cre-mediated genetic recombination and neurite outgrowth assays. Recombinant protein was already detected within hours after transduction, thereby enabling functional readouts even in relatively short-lived neuronal cultures. Altogether, these results substantiate the usefulness of baculovirus-mediated transduction of mature neurons for future research in neuroscience.
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Affiliation(s)
- Evgeny Levin
- Division of Experimental Neurology, Medical Faculty, Heinrich-Heine-University, Merowingerplatz 1a, 40225 Düsseldorf, Germany
| | - Heike Diekmann
- Division of Experimental Neurology, Medical Faculty, Heinrich-Heine-University, Merowingerplatz 1a, 40225 Düsseldorf, Germany
| | - Dietmar Fischer
- Division of Experimental Neurology, Medical Faculty, Heinrich-Heine-University, Merowingerplatz 1a, 40225 Düsseldorf, Germany
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