Embryonic Microglia Interact with Hypothalamic Radial Glia during Development and Upregulate the TAM Receptors MERTK and AXL following an Insult

Abstract

Highlights d Hypothalamic microglia survey the embryonic environment by touching radial glia cells d Embryonic microglia upregulate MERTK and AXL in response to exogenous insults d Embryonic microglia show a remarkable responsiveness to insults during gestation

Live-cell imaging of microglial interactions with radial glia in transgenic embryonic mouse brains using slice culture

“…In order to label radial glia and/or other cells with GFP (as per Rosin et al., 2021 ), 1–2 μL Adeno-associated virus (e.g., AAV2-GFP control virus) can be diluted in 5 μL slice culture medium and applied to the surface of the Cx3cr1 CreERT2 ; Rosa26 tdTomato vibratome-sectioned embryonic brain tissue in the region of interest (e.g., hypothalamus, Figure 5 F), and placed in a cell culture incubator with ambient oxygen and 5% CO 2 at 37°C for 24–48 h before imaging.…”

“…The protocol below describes the specific steps used to visualize microglial interactions with radial glia in the embryonic day 15.5 (E15.5) murine hypothalamus ( Rosin et al., 2021 ). This protocol also has been used to visualize neuronal movements in the embryonic hypothalamus and microglia-radial glia interactions in the embryonic cortex, in addition to microglial dynamics across numerous embryonic time-points from E14.5 onwards.…”

“…The advantage of this brain slice culture model is that it allows for the visualization of cellular interactions and movements in real time, especially across embryogenesis. For complete details on the use and execution of this protocol, please refer to Rosin et al. (2021) .…”

“…For complete details on the use and execution of this protocol, please refer to Rosin et al. (2021) .…”

Histamine, Neuroinflammation and Neurodevelopment: A Review

“…Increased microglial-mediated neuroinflammation has been seen in numerous NDDs, including ASD (Morgan et al, 2010;Tetreault et al, 2012;Suzuki et al, 2013;Gupta et al, 2014;Lee et al, 2017), schizophrenia (Garey, 2010;Sellgren et al, 2019;Chini et al, 2020), ADHD (Anand et al, 2017), and TS (Lennington et al, 2016). Microglia in the developing brain are also sensitive to external perturbations such as maternal infections (Smolders et al, 2015;Bernstein et al, 2016;Rosin et al, 2021a;Rosin et al, 2021b). Microglia are thought to initiate an immune response to protect the brain, but altered microglial activity has also been implicated in disorders of neurodevelopment and neurodegeneration through an upregulation of neuroinflammation (Kettenmann et al, 2011;Salter and Stevens, 2017).…”