RetSat Knockout Mitigates Hypoxia-Induced Microglial Activation by Enhancing Lipid Droplets Degradation
Wenyu Hu1, Shuoshuo Li1,2, Wenjun Shi1,3
1The Brain Science Center, Beijing Institute of Basic Medical Sciences, Beijing, China.
Abstract:
Exposure to hypoxic environments leads to neurological dysfunction, with recent studies implicating microglia-derived neuroinflammation involved in hypoxia-induced neuronal impairment. However, the underlying pathological mechanisms remain largely unclear. Lipid-droplet-accumulating microglia (LDAM) have been linked to age-related and genetic forms of neurodegeneration, prompting the investigation of their role in hypoxia-induced neuronal impairment. In this study, we observed that hypoxia induced lipid droplets accumulation in microglia, accompanied by increased levels of RETSAT, an enzyme involved in lipid metabolism regulation. Conditional knockout of RETSAT in microglia decreased lipid droplets accumulation and alleviates hypoxia-induced microglial-derived neuroinflammation and oxidative stress, both in vitro and in vivo. Our biological studies indicate that the beneficial effects of RETSAT knockout on lipid droplets degradation are primarily mediated through enhanced activity of hormone-sensitive lipase (HSL). Furthermore, we found that the hypoxic adaptation-related RETSAT mutation Q247R promotes microglia lipolysis under hypoxic conditions. These findings suggest that RetSat is a potential therapeutic target for the prevention and treatment of hypoxia-induced microglial activation.
Insights
Hypoxia causes brain dysfunction via neuroinflammation. This study reveals that targeting the enzyme RETSAT in microglia reduces harmful lipid buildup and inflammation, offering a potential treatment for hypoxia-related neurological damage.
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- Hypoxic environments can cause neurological dysfunction.
- Microglia-derived neuroinflammation is implicated in hypoxia-induced neuronal impairment, but mechanisms are unclear.
- Lipid-droplet-accumulating microglia (LDAM) are linked to neurodegeneration, suggesting a role in hypoxia.
Purpose of the Study:
- To investigate the role of lipid metabolism in microglia during hypoxia.
- To explore RETSAT as a key regulator of lipid accumulation in microglia under hypoxic conditions.
- To assess the therapeutic potential of targeting RETSAT in hypoxia-induced neuroinflammation.
Main Methods:
- Investigated hypoxia-induced changes in microglia.
- Analyzed lipid droplet accumulation and RETSAT levels in microglia.
- Utilized conditional knockout of RETSAT in microglia (in vitro and in vivo).
- Assessed neuroinflammation and oxidative stress markers.
- Examined the role of hormone-sensitive lipase (HSL) and RETSAT mutation Q247R.
Main Results:
- Hypoxia induced lipid droplet accumulation in microglia, associated with increased RETSAT.
- Conditional knockout of RETSAT in microglia reduced lipid droplets, neuroinflammation, and oxidative stress.
- RETSAT knockout enhanced lipid droplet degradation via increased HSL activity.
- The RETSAT Q247R mutation promoted microglia lipolysis under hypoxia.
Conclusions:
- RETSAT plays a critical role in regulating lipid metabolism in microglia during hypoxia.
- Targeting RETSAT can alleviate hypoxia-induced microglial activation, neuroinflammation, and oxidative stress.
- RETSAT represents a potential therapeutic target for conditions involving hypoxia-induced neurological impairment.
