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Updated: Nov 23, 2025
Author Spotlight: In Vitro Co-Culture Model for Studying Microglia-Neuronal Interactions in Disease Conditions
Published on: July 26, 2024
Microglia induce neurogenic protein expression in primary cortical cells by stimulating PI3K/AKT intracellular
Kristi Lorenzen1,2, Nicholas W Mathy1,3, Erin R Whiteford1,3
1Biology Department, Creighton University, Omaha, NE, USA.
Abstract:
Emerging evidence suggests that microglia can support neurogenesis. Little is known about the mechanisms by which microglia regulate the cortical environment and stimulate cortical neurogenesis. We used an in vitro co-culture model system to investigate the hypothesis that microglia respond to soluble signals from cortical cells, particularly following mechanical injury, to alter the cortical environment and promote cortical cell proliferation, differentiation, and survival. Analyses of cortical cell proliferation, cell death, neurogenic protein expression, and intracellular signaling were performed on uninjured and injured cortical cells in co-culture with microglial cell lines. Microglia soluble cues enhanced cortical cell viability and proliferation cortical cells. Co-culture of injured cortical cells with microglia significantly reduced cell death of cortical cells. Microglial co-culture significantly increased Nestin + and α-internexin + cortical cells. Multiplex ELISA and RT-PCR showed decreased pro-inflammatory cytokine production by microglia co-cultured with injured cortical cells. Inhibition of AKT phosphorylation in cortical cells blocked microglial-enhanced cortical cell viability and expression of neurogenic markers in vitro. This in vitro model system allows for assessment of the effect of microglial-derived soluble signals on cortical cell viability, proliferation, and stages of differentiation during homeostasis or following mechanical injury. These data suggest that microglia cells can downregulate inflammatory cytokine production following activation by mechanical injury to enhance proliferation of new cells capable of neurogenesis via activation of AKT intracellular signaling. Increasing our understanding of the mechanisms that drive microglial-enhanced cortical neurogenesis during homeostasis and following injury in vitro will provide useful information for future primary cell and in vivo studies.
Insights
Microglia (immune cells in the brain) promote neurogenesis by reducing inflammation and activating AKT signaling. This supports new cell growth and survival in the cortex, especially after injury.
Area of Science:
- Neuroscience
- Cell Biology
- Immunology
Background:
- Microglia, the brain's resident immune cells, are increasingly recognized for their supportive role in neurogenesis.
- The precise mechanisms by which microglia influence the cortical environment to stimulate neurogenesis remain largely unexplored.
- Understanding these mechanisms is crucial for developing therapeutic strategies targeting brain repair.
Purpose of the Study:
- To investigate how microglia, particularly in response to mechanical injury, modulate the cortical microenvironment.
- To test the hypothesis that microglial-derived soluble factors promote cortical cell proliferation, differentiation, and survival.
- To elucidate the intracellular signaling pathways involved in microglial-mediated neurogenesis.
Main Methods:
- Utilized an in vitro co-culture system with microglial cell lines and cortical cells (both uninjured and mechanically injured).
- Assessed cortical cell proliferation, apoptosis, expression of neurogenic markers (Nestin, α-internexin), and intracellular signaling (AKT phosphorylation).
- Analyzed cytokine production using multiplex ELISA and RT-PCR.
Main Results:
- Microglial co-culture significantly enhanced cortical cell viability and proliferation.
- Co-culture with microglia markedly reduced cell death in injured cortical cells and increased neurogenic marker expression.
- Microglia co-cultured with injured cortical cells exhibited decreased pro-inflammatory cytokine production; AKT pathway inhibition blocked microglial benefits.
Conclusions:
- Microglia can downregulate inflammatory responses following mechanical injury, thereby promoting cortical cell proliferation and neurogenesis.
- The AKT intracellular signaling pathway is critical for mediating microglial-enhanced cortical cell viability and neurogenesis.
- This in vitro model provides a valuable platform for studying microglial-cortical cell interactions in neurogenesis.
