Microglial CD206 Gene Has Potential as a State Marker of Bipolar Disorder
Masahiro Ohgidani1, Takahiro A Kato2, Yoshinori Haraguchi3
1Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University , Fukuoka , Japan.
Abstract:
The pathophysiology of bipolar disorder, especially the underlying mechanisms of the bipolarity between manic and depressive states, has yet to be clarified. Microglia, immune cells in the brain, play important roles in the process of brain inflammation, and recent positron emission tomography studies have indicated microglial overactivation in the brain of patients with bipolar disorder. We have recently developed a technique to induced microglia-like (iMG) cells from peripheral blood (monocytes). We introduce a novel translational approach focusing on bipolar disorder using this iMG technique. We hypothesize that immunological conditional changes in microglia may contribute to the shift between manic and depressive states, and thus we herein analyzed gene profiling patterns of iMG cells from three patients with rapid cycling bipolar disorder during both manic and depressive states, respectively. We revealed that the gene profiling patterns are different between manic and depressive states. The profiling pattern of case 1 showed that M1 microglia is dominant in the manic state compared to the depressive state. However, the patterns of cases 2 and 3 were not consistent with the pattern of case 1. CD206, a mannose receptor known as a typical M2 marker, was significantly downregulated in the manic state among all three patients. This is the first report to indicate the importance of shifting microglial M1/M2 characteristics, especially the CD206 gene expression pattern between depressive and manic states. Further translational studies are needed to dig up the microglial roles in the underlying biological mechanisms of bipolar disorder.
Insights
Microglia immune cell profiles differ between manic and depressive states in bipolar disorder. CD206 gene expression, a marker for M2 microglia, was lower during manic episodes, suggesting a role for immune cell shifts in bipolar disorder.
Area of Science:
- Neuroscience
- Immunology
- Psychiatry
Background:
- The precise mechanisms underlying the manic-depressive states in bipolar disorder remain unclear.
- Microglia, the brain's immune cells, are implicated in neuroinflammation and have shown overactivation in bipolar disorder patients.
- A novel technique allows for the induction of microglia-like (iMG) cells from peripheral blood monocytes.
Purpose of the Study:
- To investigate the potential role of immunological shifts in microglia in the transition between manic and depressive states in bipolar disorder.
- To analyze gene expression patterns in induced microglia-like cells from bipolar disorder patients during different mood states.
Main Methods:
- Induced microglia-like (iMG) cells were generated from peripheral blood monocytes of three rapid cycling bipolar disorder patients.
- Gene profiling of iMG cells was performed during both manic and depressive states for each patient.
- Analysis focused on identifying differential gene expression patterns related to microglial states (M1/M2) and specific markers like CD206.
Main Results:
- Gene profiling patterns of iMG cells differed significantly between manic and depressive states.
- While M1 microglia dominance was observed in mania for one patient, patterns varied across individuals.
- CD206, an M2 microglia marker, was consistently downregulated during the manic state in all three patients.
Conclusions:
- This study provides the first evidence for the dynamic shift in microglial M1/M2 characteristics, particularly CD206 expression, between manic and depressive states in bipolar disorder.
- These findings highlight the potential involvement of microglial immune responses in the pathophysiology of bipolar disorder.
- Further translational research is warranted to elucidate the specific roles of microglia in the biological mechanisms of bipolar disorder.
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