Effects on Metabolism in Astrocytes Caused by cGAMP, Which Imitates the Initial Stage of Brain Metastasis
Toya Okawa1, Kurumi Hara1, Momoko Goto1
1Clinical Pharmacology and Pharmacometrics, Graduate School of Pharmaceutical Sciences, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba 260-8675, Japan.
Abstract:
The second messenger 2'3'-cyclic-GMP-AMP (cGAMP) is thought to be transmitted from brain carcinomas to astrocytes via gap junctions, which functions to promote metastasis in the brain parenchyma. In the current study, we established a method to introduce cGAMP into astrocytes, which simulates the state of astrocytes that have been invaded by cGAMP around tumors. Astrocytes incorporating cGAMP were analyzed by metabolomics, which demonstrated that cGAMP increased glutamate production and astrocyte secretion. The same trend was observed for γ-aminobutyric acid (GABA). Conversely, glutamine production and secretion were decreased by cGAMP treatment. Due to the fundamental role of astrocytes in regulation of the glutamine-glutamate cycle, such metabolic changes may represent a potential mechanism and therapeutic target for alteration of the central nervous system (CNS) environment and the malignant transformation of brain carcinomas.
Insights
Brain cancer cells release cGAMP, affecting astrocytes. This study shows cGAMP alters astrocyte metabolism, increasing glutamate and GABA, potentially offering new brain cancer therapeutic targets.
Area of Science:
- Neuroscience
- Cancer Biology
- Metabolomics
Background:
- Astrocytes play a crucial role in regulating the central nervous system (CNS) environment.
- Brain tumor cells may influence astrocytes through the second messenger 2'3'-cyclic-GMP-AMP (cGAMP).
- cGAMP transmission via gap junctions is hypothesized to promote brain carcinoma metastasis.
Purpose of the Study:
- To investigate the metabolic impact of cGAMP on astrocytes.
- To simulate astrocyte exposure to tumor-derived cGAMP.
- To identify potential therapeutic targets for brain cancer by understanding astrocyte-cGAMP interactions.
Main Methods:
- Development of a method to introduce cGAMP into cultured astrocytes.
- Metabolomic analysis of astrocytes treated with cGAMP.
- Quantification of neurotransmitter and amino acid production and secretion.
Main Results:
- cGAMP significantly increased glutamate and gamma-aminobutyric acid (GABA) production and secretion by astrocytes.
- cGAMP treatment led to decreased glutamine production and secretion.
- These metabolic alterations highlight cGAMP's influence on astrocyte function.
Conclusions:
- cGAMP induces significant metabolic changes in astrocytes, particularly in the glutamate-glutamine cycle.
- Altered astrocyte metabolism by cGAMP may contribute to the CNS environment changes that support brain carcinoma progression.
- Targeting cGAMP-mediated astrocyte signaling presents a potential therapeutic strategy for brain cancers.
