Artikel
Alternative reactive state of tumour-associated astrocytes drive microglia transcriptional re-programming
Alternativer reaktiver Zustand tumorassoziierter Astrozyten fördert die transkriptionelle Re-Programmierung von Mikroglia
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Autoren
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Dieter Henrik Heiland
- Uniklinik Freiburg, Neurochirurgie, Freiburg, Deutschland
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Simon Behringer
- Uniklinik Freiburg, Neurochirurgie, Freiburg, Deutschland
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Pamela Franco
- Uniklinik Freiburg, Neurochirurgie, Freiburg, Deutschland
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Jürgen Beck
- Uniklinik Freiburg, Neurochirurgie, Freiburg, Deutschland
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Daniel Delev
- Universitätsklinikum Freiburg, Klinik für Neurochirurgie, Freiburg, Deutschland
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Marco Prinz
- Universitätsklinikum Freiburg, Klinik für Neuropathologie, Freiburg, Deutschland
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Oliver Schnell
- Universitätsklinikum Freiburg, Klinik für Neurochirurgie, Freiburg, Deutschland
| Veröffentlicht: | 8. Mai 2019 |
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Gliederung
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Objective: Reactive astrocytes are present after brain injury as well as in inflammatory and degenerative diseases, whereby they are subjected to a distinct transcriptomic re-programming. These reactive astrocytes constitute a major component of the cellular environment in glioblastoma, although their function and crosstalk to other components of the environment is still poorly understood.
Methods: We purified reactive astrocytes from de-novo glioblastoma and non-infiltrated cortex specimens by immunoprecipitation and analyzed the transcriptional phenotype by RNA sequencing. In order to investigate the origin of astrocytic transformation, we used a microglia loss-of-function model in human organotypic slices. Microglia was depleted by clodronat stimulation. Next, we injected tumor cells and analyzed gene expression of the astrocytes after 7d incubation by RNA sequencing. Environmental cytokines were analyzed by multi-ELISA. Immunostainings of slices were processed by confocal microscopy and 3D reconstruction.
Results: Reactive astrocytes located within the tumor revealed an alternative reactive transformation towards a progenitor stage marked by similar properties to the described A2-reactive state. We identified CD274 as a novel marker gene, highly expressed in tumor-associated astrocytes, which was immunohistochemically validated in 32 de-novo and recurrent glioblastoma specimens. Our loss-of-function model revealed a distinct JAK/STAT pathway activation in astrocytes driven by microglia-released IFN-gamma. The crosstalk between reactive transformed astrocytes and microglia cells resulted in a strong increase of anti-inflammatory cytokines (IL10 and TGF-beta) within the microenvironment of the slice model.
Conclusion: Taken together, these findings help to explain the role of reactive astrocytes of the tumor environment and strongly suggest that tumor-associated astrocytes contribute to anti-inflammatory responses and provide new opportunities for the development of innovative treatment strategies.
