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Updated: Jul 28, 2025
Isolation of Cortical Microglia with Preserved Immunophenotype and Functionality From Murine Neonates
Published on: January 30, 2014
Microglia-derived TNF-α contributes to RVLM neuronal mitochondrial dysfunction via blocking the AMPK-Sirt3 pathway in
Linping Wang1,2, Tianfeng Liu1,2, Xueping Wang2
1School of Environmental and Chemical Engineering, Shanghai University, Shanghai, China.
Background:
Neuroinflammation in the rostral ventrolateral medulla (RVLM) has been associated with the pathogenesis of stress-induced hypertension (SIH). Neuronal mitochondrial dysfunction is involved in many pathological and physiological processes. However, the impact of neuroinflammation on neuronal mitochondrial homeostasis and the involved signaling pathway in the RVLM during SIH are largely unknown.
Methods:
The morphology and phenotype of microglia and the neuronal mitochondrial injury in vivo were analyzed by immunofluorescence, Western blot, RT-qPCR, transmission electron microscopy, and kit detection. The underlying mechanisms of microglia-derived tumor necrosis factor-α (TNF-α) on neuronal mitochondrial function were investigated through in vitro and in vivo experiments such as immunofluorescence and Western blot. The effect of TNF-α on blood pressure (BP) regulation was determined in vivo via intra-RVLM microinjection of TNF-α receptor antagonist R7050.
Results:
The results demonstrated that BP, heart rate (HR), renal sympathetic nerve activity (RSNA), plasma norepinephrine (NE), and electroencephalogram (EEG) power increased in SIH rats. Furthermore, the branching complexity of microglia in the RVLM of SIH rats decreased and polarized into M1 phenotype, accompanied by upregulation of TNF-α. Increased neuronal mitochondria injury was observed in the RVLM of SIH rats. Mechanistically, Sirtuin 3 (Sirt3) and p-AMPK expression were markedly downregulated in both SIH rats and TNF-α-treated N2a cells. AMPK activator A769662 upregulated AMPK-Sirt3 signaling pathway and consequently reversed TNF-α-induced mitochondrial dysfunction. Microinjection of TNF-α receptor antagonist R7050 into the RVLM of SIH rats significantly inhibited the biological activities of TNF-α, increased p-AMPK and Sirt3 levels, and alleviated neuronal mitochondrial injury, thereby reducing c-FOS expression, RSNA, plasma NE, and BP.
Conclusions:
This study revealed that microglia-derived TNF-α in the RVLM impairs neuronal mitochondrial function in SIH possibly through inhibiting the AMPK-Sirt3 pathway. Therefore, microglia-derived TNF-α in the RVLM may be a possible therapeutic target for the intervention of SIH.
Insights
Neuroinflammation in the rostral ventrolateral medulla (RVLM) triggers stress-induced hypertension (SIH) by impairing neuronal mitochondria via tumor necrosis factor-alpha (TNF-α). Targeting TNF-α may offer a new therapeutic strategy for SIH.
Area of Science:
- Neuroscience
- Cardiovascular Physiology
- Mitochondrial Biology
Background:
- Neuroinflammation in the rostral ventrolateral medulla (RVLM) is linked to stress-induced hypertension (SIH).
- Neuronal mitochondrial dysfunction plays a role in various physiological and pathological processes.
- The specific impact of neuroinflammation on RVLM neuronal mitochondrial homeostasis during SIH remains unclear.
Purpose of the Study:
- To investigate the role of neuroinflammation in RVLM neuronal mitochondrial dysfunction during SIH.
- To elucidate the signaling pathways involved in this process.
- To explore potential therapeutic targets for SIH.
Main Methods:
- Analysis of microglia morphology and phenotype, and neuronal mitochondrial injury in SIH rats using immunofluorescence, Western blot, RT-qPCR, and electron microscopy.
- In vitro and in vivo investigation of microglia-derived tumor necrosis factor-alpha (TNF-α) effects on neuronal mitochondrial function.
- Assessment of TNF-α's impact on blood pressure regulation via RVLM microinjection of a TNF-α receptor antagonist.
Main Results:
- SIH rats exhibited increased blood pressure, heart rate, sympathetic nerve activity, and norepinephrine levels.
- RVLM microglia in SIH rats showed reduced complexity, M1 polarization, and increased TNF-α expression.
- Neuronal mitochondrial injury was observed in the RVLM, associated with downregulated AMPK-Sirtuin 3 (Sirt3) signaling.
- Inhibition of TNF-α signaling in the RVLM alleviated mitochondrial dysfunction and reduced blood pressure.
Conclusions:
- Microglia-derived TNF-α in the RVLM contributes to neuronal mitochondrial dysfunction in SIH, potentially by inhibiting the AMPK-Sirt3 pathway.
- Targeting microglia-derived TNF-α in the RVLM presents a potential therapeutic strategy for managing SIH.
