scholarly journals Complement C3-targeted gene therapy restricts onset and progression of neurodegeneration in chronic mouse glaucoma

2018 ◽  
Author(s):  
Alejandra Bosco ◽  
Sarah R Anderson ◽  
Kevin T Breen ◽  
Cesar O Romero ◽  
Michael R Steele ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Complement Activation ◽  
Ganglion Cells ◽  
Therapeutic Benefit ◽  
Complement C3 ◽  
Retinal Ganglion ◽  
Intraocular Pressure Elevation ◽  
Targeted Gene Therapy ◽  
Disease Stages ◽  
The Complement System

ABSTRACTDysregulation of the complement system is implicated in neurodegeneration, including human and animal glaucoma. Optic nerve and retinal damage in glaucoma is preceded by local complement upregulation and activation, but whether targeting this early innate immune response could have therapeutic benefit remains undefined. Because complement signals through three pathways that intersect at complement C3 activation, here we targeted this step to restore complement balance in the glaucomatous retina, and to determine its contribution to degeneration onset and/or progression. To achieve this, we combined adeno-associated viral retinal gene therapy with the targeted C3 inhibitor CR2-Crry. We show that intravitreal injection of AAV2.CR2-Crry produced sustained Crry overexpression in the retina, and reduced deposition of the activation product complement C3d on retinal ganglion cells and the inner retina of DBA/2J mice. This resulted in neuroprotection of retinal ganglion cell axons and somata despite continued intraocular pressure elevation, suggesting a direct restriction of neurodegeneration onset and progression, and significant delay to terminal disease stages. Our study uncovers a damaging effect of complement C3 or downstream complement activation in glaucoma and establishes AAV2.CR2-Crry as a viable therapeutic strategy to target pathogenic C3-mediated complement activation in the glaucomatous retina.

scholarly journals Complement modulation in the retinal pigment epithelium rescues photoreceptor degeneration in a mouse model of Stargardt disease

2017 ◽  
Vol 114 (15) ◽  
pp. 3987-3992 ◽  
Author(s):  
Tamara L. Lenis ◽  
Shanta Sarfare ◽  
Zhichun Jiang ◽  
Marcia B. Lloyd ◽  
Dean Bok ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Retinal Pigment Epithelium ◽  
Complement System ◽  
Complement Activation ◽  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Host Cells ◽  
Etiologic Factor ◽  
Photoreceptor Degeneration ◽  
The Complement System

Recessive Stargardt macular degeneration (STGD1) is caused by mutations in the gene for the ABCA4 transporter in photoreceptor outer segments. STGD1 patients and Abca4−/− (STGD1) mice exhibit buildup of bisretinoid-containing lipofuscin pigments in the retinal pigment epithelium (RPE), increased oxidative stress, augmented complement activation and slow degeneration of photoreceptors. A reduction in complement negative regulatory proteins (CRPs), possibly owing to bisretinoid accumulation, may be responsible for the increased complement activation seen on the RPE of STGD1 mice. CRPs prevent attack on host cells by the complement system, and complement receptor 1-like protein y (CRRY) is an important CRP in mice. Here we attempted to rescue the phenotype in STGD1 mice by increasing expression of CRRY in the RPE using a gene therapy approach. We injected recombinant adeno-associated virus containing the CRRY coding sequence (AAV-CRRY) into the subretinal space of 4-wk-old Abca4−/− mice. This resulted in sustained, several-fold increased expression of CRRY in the RPE, which significantly reduced the complement factors C3/C3b in the RPE. Unexpectedly, AAV-CRRY–treated STGD1 mice also showed reduced accumulation of bisretinoids compared with sham-injected STGD1 control mice. Furthermore, we observed slower photoreceptor degeneration and increased visual chromophore in 1-y-old AAV-CRRY–treated STGD1 mice. Rescue of the STGD1 phenotype by AAV-CRRY gene therapy suggests that complement attack on the RPE is an important etiologic factor in STGD1. Modulation of the complement system by locally increasing CRP expression using targeted gene therapy represents a potential treatment strategy for STGD1 and other retinopathies associated with complement dysregulation.

scholarly journals Microglial trogocytosis and the complement system regulate axonal pruning in vivo

2020 ◽  
Author(s):  
Tony K.Y. Lim ◽  
Edward S. Ruthazer
Keyword(s):  
Behavioral Response ◽  
Neural Circuit ◽  
Ex Vivo ◽  
Complement C3 ◽  
Retinal Ganglion ◽  
Inhibitory Molecule ◽  
Membrane Bound ◽  
Circuit Development ◽  
The Complement System

AbstractPartial phagocytosis—called trogocytosis—of axons by microglia has been documented in ex vivo preparations but has not been directly observed in vivo. The mechanisms that modulate microglial trogocytosis of axons and its function in neural circuit development remain poorly understood. Here we directly observe axon trogocytosis by microglia in vivo in the developing Xenopus laevis retinotectal circuit. We show that microglia regulate pruning of retinal ganglion cell axons and are important for proper behavioral response to dark and bright looming stimuli. We identify amphibian regulator of complement activation 3, a homolog of human CD46, as a neuronally-expressed synapse-associated complement inhibitory molecule that inhibits trogocytosis and axonal pruning. Using a membrane-bound complement C3 fusion protein, we demonstrate that enhancing complement activity enhances axonal pruning. Our results support the model that microglia remodel axons via trogocytosis and that neurons can control this process through expression of complement inhibitory proteins.

scholarly journals Neuroprotection of Retinal Ganglion Cells with AAV2-BDNF Pretreatment Restoring Normal TrkB Receptor Protein Levels in Glaucoma

2020 ◽  
Vol 21 (17) ◽  
pp. 6262
Author(s):  
Anna Wójcik-Gryciuk ◽  
Olga Gajewska-Woźniak ◽  
Katarzyna Kordecka ◽  
Paweł M. Boguszewski ◽  
Wioletta Waleszczyk ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Viral Vector ◽  
Ganglion Cells ◽  
Receptor Protein ◽  
Retinal Ganglion ◽  
Trkb Receptor ◽  
Protein Levels ◽  
Bdnf Signaling ◽  
Selection Of

Intravitreal delivery of brain-derived neurotrophic factor (BDNF) by injection of recombinant protein or by gene therapy can alleviate retinal ganglion cell (RGC) loss after optic nerve injury (ONI) or laser-induced ocular hypertension (OHT). In models of glaucoma, BDNF therapy can delay or halt RGCs loss, but this protection is time-limited. The decreased efficacy of BDNF supplementation has been in part attributed to BDNF TrkB receptor downregulation. However, whether BDNF overexpression causes TrkB downregulation, impairing long-term BDNF signaling in the retina, has not been conclusively proven. After ONI or OHT, when increased retinal BDNF was detected, a concomitant increase, no change or a decrease in TrkB was reported. We examined quantitatively the retinal concentrations of the TrkB protein in relation to BDNF, in a course of adeno-associated viral vector gene therapy (AAV2-BDNF), using a microbead trabecular occlusion model of glaucoma. We show that unilateral glaucoma, with intraocular pressure ( IOP) increased for five weeks, leads to a bilateral decrease of BDNF in the retina at six weeks, accompanied by up to four-fold TrkB upregulation, while a moderate BDNF overexpression in a glaucomatous eye triggers changes that restore normal TrkB concentrations, driving signaling towards long-term RGCs neuroprotection. We conclude that for glaucoma therapy, the careful selection of the appropriate BDNF concentration is the main factor securing the long-term responsiveness of RGCs and the maintenance of normal TrkB levels.

scholarly journals Long-Term Gene Therapy Causes Transgene-Specific Changes in the Morphology of Regenerating Retinal Ganglion Cells

PLoS ONE ◽  
2012 ◽  
Vol 7 (2) ◽  
pp. e31061 ◽  
Author(s):  
Jennifer Rodger ◽  
Eleanor S. Drummond ◽  
Mats Hellström ◽  
Donald Robertson ◽  
Alan R. Harvey
Keyword(s):  
Gene Therapy ◽  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Retinal Ganglion

scholarly journals Chemokine CCL5 promotes robust optic nerve regeneration and mediates many of the effects of CNTF gene therapy

2021 ◽  
Vol 118 (9) ◽  
pp. e2017282118 ◽  
Author(s):  
Lili Xie ◽  
Yuqin Yin ◽  
Larry Benowitz
Keyword(s):  
Gene Therapy ◽  
Optic Nerve ◽  
Nerve Regeneration ◽  
Viral Vectors ◽  
Ganglion Cells ◽  
Projection Neurons ◽  
Retinal Ganglion ◽  
Optic Nerve Regeneration ◽  
Beneficial Effects ◽  
Chemokine Ligand

Ciliary neurotrophic factor (CNTF) is a leading therapeutic candidate for several ocular diseases and induces optic nerve regeneration in animal models. Paradoxically, however, although CNTF gene therapy promotes extensive regeneration, recombinant CNTF (rCNTF) has little effect. Because intraocular viral vectors induce inflammation, and because CNTF is an immune modulator, we investigated whether CNTF gene therapy acts indirectly through other immune mediators. The beneficial effects of CNTF gene therapy remained unchanged after deleting CNTF receptor alpha (CNTFRα) in retinal ganglion cells (RGCs), the projection neurons of the retina, but were diminished by depleting neutrophils or by genetically suppressing monocyte infiltration. CNTF gene therapy increased expression of C-C motif chemokine ligand 5 (CCL5) in immune cells and retinal glia, and recombinant CCL5 induced extensive axon regeneration. Conversely, CRISPR-mediated knockdown of the cognate receptor (CCR5) in RGCs or treating wild-type mice with a CCR5 antagonist repressed the effects of CNTF gene therapy. Thus, CCL5 is a previously unrecognized, potent activator of optic nerve regeneration and mediates many of the effects of CNTF gene therapy.

scholarly journals Complement C3-Targeted Gene Therapy Restricts Onset and Progression of Neurodegeneration in Chronic Mouse Glaucoma

2018 ◽  
Vol 26 (10) ◽  
pp. 2379-2396 ◽  
Author(s):  
Alejandra Bosco ◽  
Sarah R. Anderson ◽  
Kevin T. Breen ◽  
Cesar O. Romero ◽  
Michael R. Steele ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Complement C3 ◽  
Targeted Gene Therapy

Gene Therapy Strategies for Glaucomatous Neurodegeneration

2021 ◽  
Vol 21 ◽  
Author(s):  
Rafael Lani-Louzada ◽  
Mariana Santana Dias ◽  
Rafael Linden ◽  
Vinicius de Toledo Ribas ◽  
Hilda Petrs-Silva
Keyword(s):  
Gene Therapy ◽  
Intraocular Pressure ◽  
Retinal Ganglion Cells ◽  
Viral Vectors ◽  
Vision Loss ◽  
Ganglion Cells ◽  
Experimental Studies ◽  
Current Treatment ◽  
Experimental Models ◽  
Retinal Ganglion

: Glaucoma leads to irreversible vision loss and current therapeutic strategies are often insufficient to prevent the progression of the disease and consequent blindness. Elevated intraocular pressure is an important risk factor, but not required for the progression of glaucomatous neurodegeneration. The demise of retinal ganglion cells represents the final common pathway of glaucomatous vision loss. Still, lifelong control of intraocular pressure is the only current treatment to prevent severe vision loss, although it frequently fails despite best practices. This scenario calls for the development of neuroprotective and pro-regenerative therapies targeting the retinal ganglion cells as well as the optic nerve. Several experimental studies have shown the potential of gene modulation as a tool for neuroprotection and regeneration. In this context, gene therapy represents an attractive approach as persistent treatment for glaucoma. Viral vectors engineered to promote overexpression of a broad range of cellular factors have been shown to protect retinal ganglion cells and/or promote axonal regeneration in experimental models. Here, we review the mechanisms involved in glaucomatous neurodegeneration and regeneration in the central nervous system. Then, we point out current limitations of gene therapy platforms and review a myriad of studies that use viral vectors to manipulate genes in retinal ganglion cells, as a strategy to promote neuroprotection and regeneration. Finally, we address the potential of combining neuroprotective and regenerative gene therapies as an approach to glaucomatous neurodegeneration.

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