scholarly journals Destructive Effect of Intravitreal Heat Shock Protein 27 Application on Retinal Ganglion Cells and Neurofilament

2020 ◽  
Vol 21 (2) ◽  
pp. 549 ◽  
Author(s):  
Pia Grotegut ◽  
Sandra Kuehn ◽  
H. Burkhard Dick ◽  
Stephanie C. Joachim
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Heat Shock Protein 27 ◽  
Bipolar Cells ◽  
Retinal Ganglion ◽  
Destructive Effect ◽  
And Control

Heat shock protein 27 (HSP27) is commonly involved in cellular stress. Increased levels of HSP27 as well as autoantibodies against this protein were previously detected in glaucoma patients. Moreover, systemic immunization with HSP27 induced glaucoma-like damage in rodents. Now, for the first time, the direct effects of an intravitreal HSP27 application were investigated. For this reason, HSP27 or phosphate buffered saline (PBS, controls) was applied intravitreally in rats (n = 12/group). The intraocular pressure (IOP) as well as the electroretinogram recordings were comparable in HSP27 and control eyes 21 days after the injection. However, significantly fewer retinal ganglion cells (RGCs) and amacrine cells were observed in the HSP27 group via immunohistochemistry and western blot analysis. The number of bipolar cells, on the other hand, was similar in both groups. Interestingly, a stronger neurofilament degeneration was observed in HSP27 optic nerves, while no differences were noted regarding the myelination state. In summary, intravitreal HSP27 injection led to an IOP-independent glaucoma-like damage. A degeneration of RGCs as well as their axons and amacrine cells was noted. This suggests that high levels of extracellular HSP27 could have a direct damaging effect on RGCs.

scholarly journals Synaptic inputs from identified bipolar and amacrine cells to a sparsely branched ganglion cell in rabbit retina

2019 ◽  
Vol 36 ◽  
Author(s):  
Andrea S. Bordt ◽  
Diego Perez ◽  
Luke Tseng ◽  
Weiley Sunny Liu ◽  
Jay Neitz ◽  
...  
Keyword(s):  
Ganglion Cell ◽  
Retinal Ganglion Cells ◽  
Amacrine Cell ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Rabbit Retina ◽  
Retinal Ganglion ◽  
Synaptic Inputs ◽  
Class Iv

AbstractThere are more than 30 distinct types of mammalian retinal ganglion cells, each sensitive to different features of the visual environment. In rabbit retina, they can be grouped into four classes according to their morphology and stratification of their dendrites in the inner plexiform layer (IPL). The goal of this study was to describe the synaptic inputs to one type of Class IV ganglion cell, the third member of the sparsely branched Class IV cells (SB3). One cell of this type was partially reconstructed in a retinal connectome developed using automated transmission electron microscopy (ATEM). It had slender, relatively straight dendrites that ramify in the sublamina a of the IPL. The dendrites of the SB3 cell were always postsynaptic in the IPL, supporting its identity as a ganglion cell. It received 29% of its input from bipolar cells, a value in the middle of the range for rabbit retinal ganglion cells studied previously. The SB3 cell typically received only one synapse per bipolar cell from multiple types of presumed OFF bipolar cells; reciprocal synapses from amacrine cells at the dyad synapses were infrequent. In a few instances, the bipolar cells presynaptic to the SB3 ganglion cell also provided input to an amacrine cell presynaptic to the ganglion cell. There was apparently no crossover inhibition from narrow-field ON amacrine cells. Most of the amacrine cell inputs were from axons and dendrites of GABAergic amacrine cells, likely providing inhibitory input from outside the classical receptive field.

Heat shock protein 90 in retinal ganglion cells: Association with axonally transported proteins

2001 ◽  
Vol 18 (3) ◽  
pp. 429-436 ◽  
Author(s):  
STEVEN L. BERNSTEIN ◽  
PAUL RUSSELL ◽  
PAUL WONG ◽  
RITA FISHELEVICH ◽  
LOIS E.H. SMITH
Keyword(s):  
Optic Nerve ◽  
Heat Shock ◽  
Heat Shock Protein ◽  
Map Kinase ◽  
Retinal Ganglion Cells ◽  
Ganglion Cells ◽  
Heat Shock Protein 90 ◽  
Kinase Assay ◽  
Neurotrophin Receptor ◽  
Retinal Ganglion

The mRNAs for heat shock protein 90 (HSP90) are found at highest levels (differentially expressed) in the primate retinal fovea, the region of highest visual acuity, compared to the peripheral retina. HSP90 expression and retinal associations were analyzed by immuno-localization, in situ hybridization, and western analysis. Retinal ganglion cells (RGCs) express much of the HSP90 mRNA present in the primate retinal fovea. A large fraction of RGC synthesized HSP90 is apparently present in the axonal compartment. To identify the role of HSP90 protein in the optic nerve and retina, co-immunoprecipitation experiments were performed, using antibodies specific for HSP90 isoforms. The immunoprecipitates were analyzed for neurotrophin receptor and ligand activities, and MAP kinase activity. MAP kinase assay was used to determine the activation state of MAP kinase associated with HSP90. HSP90 proteins selectively associate with the inactive form of full-length tyrosine kinase growth factor receptor trkB, suggesting utilization during anterograde axonal transport. Activated MAP kinase, associated with the trk downstream signaling cascade, was found to co-immunoprecipitate with optic nerve HSP90, suggesting that HSP90 may be utilized in retrograde transport of the secondary messengers associated with neurotrophin signaling. HSP90 can thus be hypothesized to play a role in bidirectional RGC axonal protein transport.

scholarly journals Different Activity Patterns in Retinal Ganglion Cells of TRPM1 and mGluR6 Knockout Mice

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Haruki Takeuchi ◽  
Sho Horie ◽  
Satoru Moritoh ◽  
Hiroki Matsushima ◽  
Tesshu Hori ◽  
...  
Keyword(s):  
Retinal Ganglion Cells ◽  
Transient Receptor Potential ◽  
Metabotropic Glutamate Receptor ◽  
Ganglion Cells ◽  
Receptor Potential ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Retinal Ganglion ◽  
Essential Components ◽  
Spontaneous Oscillations

TRPM1, the first member of the melanoma-related transient receptor potential (TRPM) subfamily, is the visual transduction channel downstream of metabotropic glutamate receptor 6 (mGluR6) on retinal ON bipolar cells (BCs). Human TRPM1 mutations are associated with congenital stationary night blindness (CSNB). In both TRPM1 and mGluR6 KO mouse retinas, OFF but not ON BCs respond to light stimulation. Here we report an unexpected difference between TRPM1 knockout (KO) and mGluR6 KO mouse retinas. We used a multielectrode array (MEA) to record spiking in retinal ganglion cells (RGCs). We found spontaneous oscillations in TRPM1 KO retinas, but not in mGluR6 KO retinas. We performed a structural analysis on the synaptic terminals of rod ON BCs. Intriguingly, rod ON BC terminals were significantly smaller in TRPM1 KO retinas than in mGluR6 KO retinas. These data suggest that a deficiency of TRPM1, but not of mGluR6, in rod ON bipolar cells may affect synaptic terminal maturation. We speculate that impaired signaling between rod BCs and AII amacrine cells (ACs) leads to spontaneous oscillations. TRPM1 and mGluR6 are both essential components in the signaling pathway from photoreceptors to ON BC dendrites, yet they differ in their effects on the BC terminal and postsynaptic circuitry.

scholarly journals N-type and L-type calcium channels mediate glycinergic synaptic inputs to retinal ganglion cells of tiger salamanders

2004 ◽  
Vol 21 (4) ◽  
pp. 545-550 ◽  
Author(s):  
MARK C. BIEDA ◽  
DAVID R. COPENHAGEN
Keyword(s):  
Calcium Channels ◽  
Retinal Ganglion Cells ◽  
Channel Blocker ◽  
Ganglion Cells ◽  
Amacrine Cells ◽  
Bipolar Cells ◽  
Retinal Ganglion ◽  
Tiger Salamanders ◽  
Synaptic Release ◽  
Glycine Release

Synaptically localized calcium channels shape the timecourse of synaptic release, are a prominent site for neuromodulation, and have been implicated in genetic disease. In retina, it is well established that L-type calcium channels play a major role in mediating release of glutamate from the photoreceptors and bipolar cells. However, little is known about which calcium channels are coupled to synaptic exocytosis of glycine, which is primarily released by amacrine cells. A recent report indicates that glycine release from spiking AII amacrine cells relies exclusively upon L-type calcium channels. To identify calcium channel types controlling neurotransmitter release from the population of glycinergic neurons that drive retinal ganglion cells, we recorded electrical and potassium evoked inhibitory synaptic currents (IPSCs) from these postsynaptic neurons in retinal slices from tiger salamanders. The L-channel antagonist nifedipine strongly inhibited release and FPL64176, an L-channel agonist, greatly enhanced it, indicating a significant role for L-channels. ω-Conotoxin MVIIC, an N/P/Q-channel antagonist, strongly inhibited release, indicating an important role for non-L channels. While the P/Q-channel blocker ω-Aga IVA produced only small effects, the N-channel blocker ω-conotoxin GVIA strongly inhibited release. Hence, N-type and L-type calcium channels appear to play major roles, overall, in mediating synaptic release of glycine onto retinal ganglion cells.

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