Microglial depletion decreases Müller cell maturation and inner retinal vascular density
Nathaniel Rowthorn-Apel1, Naveen Vridhachalam2, Kip M Connor3
1Department of Ophthalmology, Tufts University School of Medicine, Tufts Medical Center, Boston, MA, 02111, USA.
Background:
The neuroretinal vascular system is comprised of three interconnected layers. The initial superficial vascular plexus formation is guided by astrocytes around birth in mice. The formation of the deep and intermediate vascular plexuses occurs in the second postnatal week and is driven by Müller-cell-derived angiogenic signaling. Previously, we reported that microglia play an important role in regulating astrocyte density during superficial vascular plexus formation. Here, we investigated the role of microglia in regulating Müller-cell-dependent inner retinal vascular development.
Methodology:
In this study, we depleted microglia during retinal development using Csf1R antagonist (PLX5622). We characterized the developmental progression of inner retinal vascular growth, effect of microglial depletion on inner retinal vascular growth and Müller cell marker expressions by immunostaining. Differential expressions of genes in the control and microglia depleted groups were analyzed by mRNA-seq and qPCR. Unpaired t-test was performed to determine the statistical differences between groups.
Results:
This study show that microglia interact with Müller cells and the growing inner retinal vasculature. Depletion of microglia resulted in reduced inner retinal vascular layers densities and decreased Vegfa isoforms transcript levels. RNA-seq analysis further revealed that microglial depletion significantly reduced specific Müller cell maturation markers including glutamine synthetase, responsible for glutamine biosynthesis, necessary for angiogenesis.
Conclusions:
Our study reveals an important role for microglia in facilitating inner retinal angiogenesis and Müller cell maturation.
Insights
Microglia are crucial for inner retinal vascular development. This study shows microglia support Müller cell maturation and blood vessel growth in the retina.
Area of Science:
- Neuroscience
- Ophthalmology
- Developmental Biology
Background:
- The neuroretinal vascular system forms in three layers, with deep and intermediate layers developing postnatally.
- Müller cells drive inner retinal vascular development through angiogenic signaling.
- Microglia regulate astrocyte density in superficial vascular plexus formation.
Purpose of the Study:
- To investigate the role of microglia in Müller cell-dependent inner retinal vascular development.
- To understand how microglia influence the formation of deep and intermediate retinal vascular layers.
Main Methods:
- Microglia were depleted in developing mice using a Csf1R antagonist (PLX5622).
- Inner retinal vascular growth and Müller cell markers were assessed via immunostaining.
- Gene expression differences were analyzed using mRNA-seq and qPCR.
Main Results:
- Microglia interact with Müller cells and developing retinal vasculature.
- Microglial depletion reduced inner retinal vascular layer density and Vegfa transcript levels.
- Key Müller cell maturation markers, like glutamine synthetase, were significantly reduced after microglial depletion.
Conclusions:
- Microglia play a significant role in facilitating inner retinal angiogenesis.
- Microglia are important for Müller cell maturation, which is essential for retinal vascular development.
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