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6-Hydroxydopamine Induces Abnormal Iron Sequestration in BV2 Microglia by Activating Iron Regulatory Protein 1 and
Manman Xu1,2,3, Yinghui Li1,2, Dapeng Meng1,2
1School of Basic Medicine, Qingdao University, Qingdao 266071, China.
Abstract:
Disrupted iron homeostasis in the substantia nigra pars compacta (SNpc) is an important pathological mechanism in Parkinson's disease (PD). It is unclear what role microglia play in iron metabolism and selective iron deposition in the SNpc of PD brain. In this study, we observed that 6-hydroxydopamine (6-OHDA) induced the expression of divalent metal transporter-1 (DMT1) and iron influx in BV2 microglia cells, which might be associated with the upregulation of iron regulatory protein 1 (IRP1) expression. Moreover, we found that 6-OHDA had no significant effect on the expression of ferroportin 1 (FPN1) and iron efflux in BV2 microglial cells, which might be the combined action of IRP1 upregulation and reduced hepcidin levels. Furthermore, 6-OHDA treatment activated BV2 microglia and enhanced the release of pro-inflammatory cytokines. Interestingly, iron overloading suppressed IRP1 expression, thus downregulating DMT1 and upregulating FPN1 levels in these microglial cells. On the contrary, iron deficiency activated IRP1, leading to increased expression of DMT1 and decreased expression of FPN1-which indicates that activated IRP1 induces iron overloading in 6-OHDA-treated microglia, but not iron overloading modulates the expression of IRP1. Taken together, our data suggest that 6-OHDA can regulate the expression of DMT1 and FPN1 by activating IRP1 and inhibiting hepcidin release, thus leading to abnormal iron sequestration in microglia. In addition, 6-OHDA can activate microglia, which leads to increased release of pro-inflammatory factors that can further induce genome damage in dopaminergic neurons.
Insights
Parkinson's disease involves disrupted iron in the brain. This study shows 6-hydroxydopamine (6-OHDA) causes microglia to accumulate iron by altering iron transporter expression, contributing to neuroinflammation.
Area of Science:
- Neuroscience
- Cell Biology
- Biochemistry
Background:
- Iron homeostasis disruption in the substantia nigra pars compacta (SNpc) is key in Parkinson's disease (PD).
- The specific role of microglia in SNpc iron metabolism and deposition in PD remains unclear.
Purpose of the Study:
- To investigate the role of microglia in iron dysregulation within the context of Parkinson's disease pathology.
- To elucidate the mechanisms by which 6-hydroxydopamine (6-OHDA) affects microglial iron transport and inflammatory responses.
Main Methods:
- Utilized BV2 microglial cell models treated with 6-hydroxydopamine (6-OHDA).
- Assessed the expression of iron-related proteins, including divalent metal transporter-1 (DMT1) and ferroportin 1 (FPN1).
- Measured iron influx and efflux, and inflammatory cytokine release.
Main Results:
- 6-OHDA treatment increased DMT1 expression and iron influx in microglia, linked to upregulated iron regulatory protein 1 (IRP1).
- 6-OHDA did not significantly alter FPN1 expression or iron efflux, potentially due to IRP1 upregulation and reduced hepcidin.
- Microglial activation by 6-OHDA enhanced pro-inflammatory cytokine release; iron overload/deficiency modulated IRP1, DMT1, and FPN1 in a manner dependent on 6-OHDA treatment.
Conclusions:
- 6-OHDA alters microglial iron metabolism by activating IRP1 and inhibiting hepcidin, leading to abnormal iron sequestration.
- Activated microglia release pro-inflammatory factors, potentially causing further damage to dopaminergic neurons in PD.
