Effects of 3D Stratification of Retinal Ganglion Cells in Sholl Analysis

Gobran, John; Rawlyk, Brooklyn; Henderson, Delaney Cm; Hooper, Michele L.; Farrell, Spencer; Chauhan, Balwantray C.

doi:10.1016/j.jneumeth.2020.108907

Cited by 5 publications

(4 citation statements)

References 15 publications

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“…Five-second illumination of blue (445 nm) light was used to elicit intrinsic melanopsin responses at 5 × 10 13 log photons/cm −2 /s −1 using a Texas Instruments DLP4500 LightCrafter projector and custom software (pyStim 103 ; https://github.com/SivyerLab/pyStim). Some ipRGCs were targeted for Neurobiotin electroporation using methods described previously 104,105 .…”

Section: Methodsmentioning

confidence: 99%

A melanopsin ganglion cell subtype forms a dorsal retinal mosaic projecting to the supraoptic nucleus

et al. 2023

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Visual input to the hypothalamus from intrinsically photosensitive retinal ganglion cells (ipRGCs) influences several functions including circadian entrainment, body temperature, and sleep. ipRGCs also project to nuclei such as the supraoptic nucleus (SON), which is involved in systemic fluid homeostasis, maternal behavior, social behaviors, and appetite. However, little is known about the SON-projecting ipRGCs or their relationship to well-characterized ipRGC subtypes. Using a GlyT2Cre mouse line, we show a subtype of ipRGCs restricted to the dorsal retina that selectively projects to the SON. These ipRGCs tile a dorsal region of the retina, forming a substrate for encoding ground luminance. Optogenetic activation of their axons demonstrates they release the neurotransmitter glutamate in multiple regions, including the suprachiasmatic nucleus (SCN) and SON. Our results challenge the idea that ipRGC dendrites overlap to optimize photon capture and suggests non-image forming vision operates to sample local regions of the visual field to influence diverse behaviors.

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Section: Methodsmentioning

confidence: 99%

A melanopsin ganglion cell subtype forms a dorsal retinal mosaic projecting to the supraoptic nucleus

et al. 2023

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“…Finally, the Xtension of Filament Sholl Analysis was employed to assess the branching patterns of GAM foot processes by superimposing concentric rings 1 μm apart and quantifying the number of the intersections of bifurcation points intersecting each ring. [66] Filipin Staining: Filipin staining was used to assess non-esterified cholesterol. [67] Frozen brain sections were fixed with 4% PFA, followed by overnight incubation with a combination of 20 μg mL −1 of Filipin complex (MCE, #HY-N6716) and primary antibodies in 10% bovine serum albumin in PBS, and then incubated with secondary antibodies.…”

Section: Methodsmentioning

confidence: 99%

“…Finally, the Xtension of Filament Sholl Analysis was employed to assess the branching patterns of GAM foot processes by superimposing concentric rings 1 µm apart and quantifying the number of the intersections of bifurcation points intersecting each ring. [ 66 ]…”

Section: Methodsmentioning

confidence: 99%

PERK‐Mediated Cholesterol Excretion from IDH Mutant Glioma Determines Anti‐Tumoral Polarization of Microglia

et al. 2023

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Isocitrate dehydrogenase (IDH) mutation, a known pathologic classifier, initiates metabolic reprogramming in glioma cells and has been linked to the reaction status of glioma-associated microglia/macrophages (GAMs). However, it remains unclear how IDH genotypes contribute to GAM phenotypes. Here, it is demonstrated that gliomas expressing mutant IDH determine M1-like polarization of GAMs, while archetypal IDH induces M2-like polarization. Intriguingly, IDH-mutant gliomas secrete excess cholesterol, resulting in cholesterol-rich, pro-inflammatory GAMs without altering their cholesterol biosynthesis, and simultaneously exhibiting low levels of tumoral cholesterol due to expression remodeling of cholesterol transport molecules, particularly upregulation of ABCA1 and downregulation of LDLR. Mechanistically, a miR-19a/LDLR axis-mediated novel post-transcriptional regulation of cholesterol uptake is identified, modulated by IDH mutation, and influencing tumor cell proliferation and invasion. IDH mutation-induced PERK activation enhances cholesterol export from glioma cells via the miR-19a/LDLR axis and ABCA1/APOE upregulation. Further, a synthetic PERK activator, CCT020312 is introduced, which markedly stimulates cholesterol efflux from IDH wild-type glioma cells, induces M1-like polarization of GAMs, and consequently suppresses glioma cell invasion. The findings reveal an essential role of the PERK/miR-19a/LDLR signaling pathway in orchestrating gliomal cholesterol transport and the subsequent phenotypes of GAMs, thereby highlighting a novel potential target pathway for glioma therapy.

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“…Although Sholl analysis is an established and widely used method for evaluating neuronal morphologies, it has a number of issues and limitations. Although some 3-dimensional Sholl methods exist ( Ruthazer and Cline, 2002 ; Binley et al, 2014 ; Gobran et al, 2020 ), Sholl analysis is typically performed using a 2-dimensional array of concentric rings positioned over a 2-dimensional tracing of a neuron. Therefore, distance in the z-plane is discounted and two branching points within the same Sholl ring can be far apart in the z-direction.…”

Section: Introductionmentioning

confidence: 99%

Investigating Fractal Analysis as a Diagnostic Tool That Probes the Connectivity of Hippocampal Neurons

et al. 2022

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Many of nature’s fractal objects benefit from the favorable functionality that results from their pattern repetition at multiple scales. Our recent research focused on the importance of fractal scaling in establishing connectivity between neurons. Fractal dimension DA of the neuron arbors was shown to relate to the optimization of competing functional constraints—the ability of dendrites to connect to other neurons versus the costs associated with building the dendrites. Here, we consider whether pathological states of neurons might affect this fractal optimization and if changes in DA might therefore be used as a diagnostic tool in parallel with traditional measures like Sholl analyses. We use confocal microscopy to obtain images of CA1 pyramidal neurons in the coronal plane of the dorsal rat hippocampus and construct 3-dimensional models of the dendritic arbors using Neurolucida software. We examine six rodent groups which vary in brain condition (whether they had lesions in the anterior thalamic nuclei, ATN) and experience (their housing environment and experience in a spatial task). Previously, we showed ATN lesions reduced spine density in hippocampal CA1 neurons, whereas enriched housing increased spine density in both ATN lesion and sham rats. Here, we investigate whether ATN lesions and experience also effect the complexity and connectivity of CA1 dendritic arbors. We show that sham rats exposed to enriched housing and spatial memory training exhibited higher complexity (as measured by DA) and connectivity compared to other groups. When we categorize the rodent groups into those with or without lesions, we find that both categories achieve an optimal balance of connectivity with respect to material cost. However, the DA value used to achieve this optimization does not change between these two categories, suggesting any morphological differences induced by the lesions are too small to influence the optimization process. Accordingly, we highlight considerations associated with applying our technique to publicly accessible repositories of neuron images with a broader range of pathological conditions.

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Effects of 3D Stratification of Retinal Ganglion Cells in Sholl Analysis

Cited by 5 publications

References 15 publications

A melanopsin ganglion cell subtype forms a dorsal retinal mosaic projecting to the supraoptic nucleus

A melanopsin ganglion cell subtype forms a dorsal retinal mosaic projecting to the supraoptic nucleus

PERK‐Mediated Cholesterol Excretion from IDH Mutant Glioma Determines Anti‐Tumoral Polarization of Microglia

Investigating Fractal Analysis as a Diagnostic Tool That Probes the Connectivity of Hippocampal Neurons

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