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Developmental stage of oligodendrocytes determines their response to activated microglia in vitro.

Miller BA, Crum JM, Tovar CA, Ferguson AR, Bresnahan JC, Beattie MS - J Neuroinflammation (2007)

Bottom Line: Lipopolysaccharide was used to activate microglia and microglial activation was confirmed by TNFalpha ELISA.Activated microglia reduced OPC survival, but increased survival and reduced apoptosis of mature oligodendrocytes.Activated microglia may have divergent effects on OPCs and mature oligodendrocytes, reducing OPC survival and increasing mature oligodendrocyte survival.

View Article: PubMed Central - HTML - PubMed

Affiliation: Brain and Spinal Injury Center, Department of Neurological Surgery, University of California San Francisco, 1001 Potrero Ave, Building 1, Room 101, San Francisco, CA 94143, USA. Brandon.Miller@osumc.edu

ABSTRACT

Background: Oligodendrocyte progenitor cells (OPCs) and mature oligodendrocytes are both lost in central nervous system injury and disease. Activated microglia may play a role in OPC and oligodendrocyte loss or replacement, but it is not clear how the responses of OPCs and oligodendrocytes to activated microglia differ.

Methods: OPCs and microglia were isolated from rat cortex. OPCs were induced to differentiate into oligodendrocytes with thyroid hormone in defined medium. For selected experiments, microglia were added to OPC or oligodendrocyte cultures. Lipopolysaccharide was used to activate microglia and microglial activation was confirmed by TNFalpha ELISA. Cell survival was assessed with immunocytochemistry and cell counts. OPC proliferation and oligodendrocyte apoptosis were also assessed.

Results: OPCs and oligodendrocytes displayed phenotypes representative of immature and mature oligodendrocytes, respectively. Activated microglia reduced OPC survival, but increased survival and reduced apoptosis of mature oligodendrocytes. Activated microglia also underwent cell death themselves.

Conclusion: Activated microglia may have divergent effects on OPCs and mature oligodendrocytes, reducing OPC survival and increasing mature oligodendrocyte survival. This may be of importance because activated microglia are present in several disease states where both OPCs and mature oligodendrocytes are also reacting to injury. Activated microglia may simultaneously have deleterious and helpful effects on different cells after central nervous system injury.

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Assessment of microglial cell death. In experiments in which microglia were combined with OPCs, 10 ng/ml LPS significantly reduced microglia number to 58 ± 8% of control, based on cell counts (A). In experiments in which microglia were combined with oligodendrocytes, 10 ng/ml LPS significantly reduced microglia number to 14 ± 2% of control (B, * = p < 0.05, T-test, error bars = SEM).
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Figure 8: Assessment of microglial cell death. In experiments in which microglia were combined with OPCs, 10 ng/ml LPS significantly reduced microglia number to 58 ± 8% of control, based on cell counts (A). In experiments in which microglia were combined with oligodendrocytes, 10 ng/ml LPS significantly reduced microglia number to 14 ± 2% of control (B, * = p < 0.05, T-test, error bars = SEM).

Mentions: Microglia survival was assessed after LPS activation in experiments where OPC and oligodendrocyte survival were measured. In experiments conducted with microglia in combined culture with OPCs, where media contained bFGF and PDGF, microglia survival was significantly decreased to 58 ± 8% of control values after treatment with 10 ng/ml LPS for 24 hours (p < 0.001, Student's T-test, Fig. 8A). In experiments conducted with microglia in culture with oligodendrocytes in media containing thyroid hormone, microglia numbers were significantly decreased to 14 ± 2% of control values after treatment with 10 ng/ml LPS for 24 hours (p < 0.001, Student's T-test, Fig. 8B).


Developmental stage of oligodendrocytes determines their response to activated microglia in vitro.

Miller BA, Crum JM, Tovar CA, Ferguson AR, Bresnahan JC, Beattie MS - J Neuroinflammation (2007)

Assessment of microglial cell death. In experiments in which microglia were combined with OPCs, 10 ng/ml LPS significantly reduced microglia number to 58 ± 8% of control, based on cell counts (A). In experiments in which microglia were combined with oligodendrocytes, 10 ng/ml LPS significantly reduced microglia number to 14 ± 2% of control (B, * = p < 0.05, T-test, error bars = SEM).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2214724&req=5

Figure 8: Assessment of microglial cell death. In experiments in which microglia were combined with OPCs, 10 ng/ml LPS significantly reduced microglia number to 58 ± 8% of control, based on cell counts (A). In experiments in which microglia were combined with oligodendrocytes, 10 ng/ml LPS significantly reduced microglia number to 14 ± 2% of control (B, * = p < 0.05, T-test, error bars = SEM).
Mentions: Microglia survival was assessed after LPS activation in experiments where OPC and oligodendrocyte survival were measured. In experiments conducted with microglia in combined culture with OPCs, where media contained bFGF and PDGF, microglia survival was significantly decreased to 58 ± 8% of control values after treatment with 10 ng/ml LPS for 24 hours (p < 0.001, Student's T-test, Fig. 8A). In experiments conducted with microglia in culture with oligodendrocytes in media containing thyroid hormone, microglia numbers were significantly decreased to 14 ± 2% of control values after treatment with 10 ng/ml LPS for 24 hours (p < 0.001, Student's T-test, Fig. 8B).

Bottom Line: Lipopolysaccharide was used to activate microglia and microglial activation was confirmed by TNFalpha ELISA.Activated microglia reduced OPC survival, but increased survival and reduced apoptosis of mature oligodendrocytes.Activated microglia may have divergent effects on OPCs and mature oligodendrocytes, reducing OPC survival and increasing mature oligodendrocyte survival.

View Article: PubMed Central - HTML - PubMed

Affiliation: Brain and Spinal Injury Center, Department of Neurological Surgery, University of California San Francisco, 1001 Potrero Ave, Building 1, Room 101, San Francisco, CA 94143, USA. Brandon.Miller@osumc.edu

ABSTRACT

Background: Oligodendrocyte progenitor cells (OPCs) and mature oligodendrocytes are both lost in central nervous system injury and disease. Activated microglia may play a role in OPC and oligodendrocyte loss or replacement, but it is not clear how the responses of OPCs and oligodendrocytes to activated microglia differ.

Methods: OPCs and microglia were isolated from rat cortex. OPCs were induced to differentiate into oligodendrocytes with thyroid hormone in defined medium. For selected experiments, microglia were added to OPC or oligodendrocyte cultures. Lipopolysaccharide was used to activate microglia and microglial activation was confirmed by TNFalpha ELISA. Cell survival was assessed with immunocytochemistry and cell counts. OPC proliferation and oligodendrocyte apoptosis were also assessed.

Results: OPCs and oligodendrocytes displayed phenotypes representative of immature and mature oligodendrocytes, respectively. Activated microglia reduced OPC survival, but increased survival and reduced apoptosis of mature oligodendrocytes. Activated microglia also underwent cell death themselves.

Conclusion: Activated microglia may have divergent effects on OPCs and mature oligodendrocytes, reducing OPC survival and increasing mature oligodendrocyte survival. This may be of importance because activated microglia are present in several disease states where both OPCs and mature oligodendrocytes are also reacting to injury. Activated microglia may simultaneously have deleterious and helpful effects on different cells after central nervous system injury.

Show MeSH
Related in: MedlinePlus