CD82 protects against glaucomatous axonal transport deficits via mTORC1 activation in mice

AbstractGlaucoma is a leading cause of irreversible blindness worldwide and is characterized by progressive optic nerve degeneration and retinal ganglion cell loss. Axonal transport deficits have been demonstrated to be the earliest crucial pathophysiological changes underlying axonal degeneration in glaucoma. Here, we explored the role of the tetraspanin superfamily member CD82 in an acute ocular hypertension model. We found a transient downregulation of CD82 after acute IOP elevation, with parallel emergence of axonal transport deficits. The overexpression of CD82 with an AAV2/9 vector in the mouse retina improved optic nerve axonal transport and ameliorated subsequent axon degeneration. Moreover, the CD82 overexpression stimulated optic nerve regeneration and restored vision in a mouse optic nerve crush model. CD82 exerted a protective effect through the upregulation of TRAF2, which is an E3 ubiquitin ligase, and activated mTORC1 through K63-linked ubiquitylation and intracellular repositioning of Raptor. Therefore, our study offers deeper insight into the tetraspanin superfamily and demonstrates a potential neuroprotective strategy in glaucoma treatment.

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CD82 Protects Against Glaucomatous Axonal Transport Deficits via mTORC1 Activation in Mice

10.21203/rs.3.rs-404388/v1 ◽

2021 ◽

Author(s):

Yin Zhao ◽

Meng Ye ◽

Jingqiu Huang ◽

Qianxue Mou ◽

Jing Luo ◽

...

Keyword(s):

Optic Nerve ◽

Neurite Outgrowth ◽

Ocular Hypertension ◽

Axonal Transport ◽

Nerve Degeneration ◽

Mouse Retina ◽

Optic Nerve Crush ◽

Nerve Crush ◽

Neuroprotective Strategy

Abstract Background: Glaucoma is a leading cause of irreversible blindness worldwide characterized by progressive optic nerve degeneration and retinal ganglion cell (RGC) loss. Axonal transport deficits have been demonstrated to be the earliest crucial pathophysiological changes underlying axonal degeneration in glaucoma. The critical feature of this pathological process and the significance of early intervention remain to be further explored. Here, we explore the role of a tetraspanin superfamily member CD82 in protection of glaucomatous neurodegeneration in an acute ocular hypertension mouse model. Methods:Expression level of CD82 in retina was examined before and after an acute ocular hypertension (AOHT) model in mouse. Overexpression of CD82 was achieved by intraocular injection of adeno-associated virus vector expressing CD82. Axonal transport deficits were evaluated by intravitreally injected Cholera toxin B (CTB) from eyes to superior colliculus and the distribution of endogenous synaptophysin. Subsequent optic nerve (ON) degeneration phenotypes were also examined including axon loss, myelin damage, and Aβ accumulation. In vitro neurite outgrowth assay was performed in SH-SY5Y cells with Cd82-plasmid transfection. Another optic nerve crush (ONC) model was taken to further validate the neuroprotective effects of CD82 by evaluation of axonal regeneration, RGC survival, and visual function of mice. Downstream pathway of CD82 was analyzed by qPCR examination and western blotting analysis as well as phenotype detection.Results:We found a transient downregulation of CD82 after acute IOP elevation, with parallel emergence of axonal transport deficits. Overexpression of CD82 with AAV2/9 vector in mouse retina improved optic nerve (ON) axonal transport and ameliorated subsequent axon degeneration. In vitro neurite outgrowth assay displayed longer neurite length of SH-SY5Y cells with transfection of Cd82-plasmid. Moreover, CD82 overexpression could stimulate ON regeneration and restore mouse vision after an optic nerve crush model. CD82 exerted protective effect through upregulation of TRAF2, which was an E3 ubiquitin ligase and activated mTORC1 through K63-linked ubiquitylation and intracellular repositioning of Raptor. Conclusions:These findings indicate that CD82 overexpression protects against glaucomatous axonal transport deficits through TRAF2-dependent activation of mTORC1 pathway, which offers deeper insights into tetraspanins superfamily and demonstrated potential neuroprotective strategy in glaucoma treatments.

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Nerve fibre layer degeneration and retinal ganglion cell loss long term after optic nerve crush or transection in adult mice

Experimental Eye Research ◽

10.1016/j.exer.2018.02.010 ◽

2018 ◽

Vol 170 ◽

pp. 40-50 ◽

Cited By ~ 19

Author(s):

M.C. Sánchez-Migallón ◽

F.J. Valiente-Soriano ◽

M. Salinas-Navarro ◽

F.M. Nadal-Nicolás ◽

M. Jiménez-López ◽

...

Keyword(s):

Optic Nerve ◽

Ganglion Cell ◽

Nerve Fibre ◽

Cell Loss ◽

Optic Nerve Crush ◽

Retinal Ganglion ◽

Nerve Crush ◽

Adult Mice ◽

Nerve Fibre Layer

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Protective Effect of Bax Ablation Against Cell Loss in the Retinal Ganglion Layer Induced by Optic Nerve Crush in Transgenic Mice

Journal of Neuro-Ophthalmology ◽

10.1097/wno.0b013e318227e4fb ◽

2011 ◽

Vol 31 (4) ◽

pp. 331-338 ◽

Cited By ~ 9

Author(s):

Nitza Goldenberg-Cohen ◽

Olga Dratviman-Storobinsky ◽

Shimrit Dadon Bar El ◽

Yelena Cheporko ◽

Edith Hochhauser

Keyword(s):

Optic Nerve ◽

Transgenic Mice ◽

Protective Effect ◽

Cell Loss ◽

Optic Nerve Crush ◽

Retinal Ganglion ◽

Nerve Crush

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Corrigendum to “Nerve fibre layer degeneration and retinal ganglion cell loss long term after optic nerve crush or transection in adult mice” [Exp Eye Res. (2018) 170:40–50. doi: 10.1016/j.exer.2018.02.010. Epub 2018 Feb 13]

Experimental Eye Research ◽

10.1016/j.exer.2019.107875 ◽

2020 ◽

Vol 190 ◽

pp. 107875

Author(s):

M.C. Sánchez-Migallón ◽

F.J. Valiente-Soriano ◽

M. Salinas-Navarro ◽

F.M. Nadal-Nicolás ◽

M. Jiménez-López ◽

...

Keyword(s):

Optic Nerve ◽

Ganglion Cell ◽

Nerve Fibre ◽

Cell Loss ◽

Optic Nerve Crush ◽

Retinal Ganglion ◽

Nerve Crush ◽

Adult Mice ◽

Nerve Fibre Layer

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Transfer of the Experimental Autoimmune Glaucoma Model from Rats to Mice—New Options to Study Glaucoma Disease

International Journal of Molecular Sciences ◽

10.3390/ijms20102563 ◽

2019 ◽

Vol 20 (10) ◽

pp. 2563 ◽

Cited By ~ 5

Author(s):

Sabrina Reinehr ◽

Jacqueline Reinhard ◽

Susanne Wiemann ◽

Karoline Hesse ◽

Christina Voss ◽

...

Keyword(s):

Optic Nerve ◽

Ganglion Cells ◽

Nerve Degeneration ◽

Retinal Ganglion ◽

Retinal Neurons ◽

Optic Nerves ◽

Gabaergic Synapses ◽

Optic Nerve Degeneration ◽

Experimental Autoimmune

Studies have suggested an involvement of the immune system in glaucoma. Hence, a rat experimental autoimmune glaucoma model (EAG) was developed to investigate the role of the immune response. Here, we transferred this model into mice. Either 0.8 mg/mL of the optic nerve antigen homogenate (ONA; ONA 0.8) or 1.0 mg/mL ONA (ONA 1.0) were injected in 129/Sv mice. Controls received sodium chloride. Before and 6 weeks after immunization, the intraocular pressure (IOP) was measured. At 6 weeks, retinal neurons, glia cells, and synapses were analyzed via immunohistology and quantitative real-time PCR (RT-qPCR). Additionally, optic nerves were examined. The IOP stayed in the normal physiological range throughout the study (p > 0.05). A significant reduction of retinal ganglion cells (RGCs) was noted in both immunized groups (p < 0.001). Remodeling of glutamatergic and GABAergic synapses was seen in ONA 1.0 retinas. Furthermore, both ONA groups revealed optic nerve degeneration and macrogliosis (all: p < 0.001). An increase of activated microglia was noted in ONA retinas and optic nerves (p < 0.05). Both ONA concentrations led to RGC loss and optic nerve degeneration. Therefore, the EAG model was successfully transferred from rats to mice. In further studies, transgenic knockout mice can be used to investigate the pathomechanisms of glaucoma more precisely.

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Correlation between Retinal Ganglion Cell Loss and Nerve Crush Force-Impulse Established with Instrumented Tweezers in Mice

10.1101/687616 ◽

2019 ◽

Author(s):

Xiaorong Liu ◽

Liang Feng ◽

Ishan Shinde ◽

James D. Cole ◽

John B. Troy ◽

...

Keyword(s):

Optic Nerve ◽

Real Time ◽

Molecular Mechanisms ◽

Ganglion Cells ◽

Cell Loss ◽

Retinal Ganglion ◽

Nerve Crush ◽

Axon Loss ◽

Axon Damage ◽

First Time

AbstractObjectivesRodent models of optic nerve crush (ONC) have often been used to study degeneration and regeneration of retinal ganglion cells (RGCs) and their axons as well as the underlying molecular mechanisms. However, ONC results from different laboratories exhibit a range of RGC injury with varying degree of axonal damage. We developed an instrumented tweezers to measure optic nerve (ON) crush forces in real time and studied the correlation between RGC axon loss and force-impulse, the product of force and duration, applied through the instrumented tweezers in mice.MethodsA pair of standard self-closing #N7 tweezers were instrumented with miniature foil strain gauges at optimal locations on both tweezer arms. The instrumented tweezers were capable of recording the tip closure forces in the form of voltages, which were calibrated through load cells to corresponding tip closure forces over the operating range. Using the instrumented tweezers, the ONs of multiple mice were crushed with varied forces and durations and the axons in the immunostained sections of the crushed ONs were counted.ResultsWe found that the surviving axon density correlated with crush force, with longer duration and stronger crush forces producing consistently more axon damage.DiscussionThe instrumented tweezers enable a simple technique for measurement of ONC forces in real-time for the first time. Using the instrumented tweezers, experimenters can quantify crush forces during ONC to produce consistent and predictable post-crush cell death. This should permit future studies a way to produce nerve damage more consistently than is available now.

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