Impaired microglia process dynamics post-stroke are specific to sites of secondary neurodegeneration

Murielle G. Kluge, Laura Kracht, Mahmoud Abdolhoseini, Lin Kooi Ong, Sarah J. Johnson, Michael Nilsson, Frederick R. Walker*

*Corresponding author for this work

    Research output: Contribution to journalArticleAcademicpeer-review

    23 Citations (Scopus)

    Abstract

    Stroke induces tissue death both at the site of infarction and at secondary sites connected to the primary infarction. This latter process has been referred to as secondary neurodegeneration (SND). Using predominantly fixed tissue analyses, microglia have been implicated in regulating the initial response at both damage sites post-stroke. In this study, we used acute slice based multiphoton imaging, to investigate microglia dynamic process movement in mice 14 days after a photothrombotic stroke. We evaluated the baseline motility and process responses to locally induced laser damage in both the peri-infarct (PI) territory and the ipsilateral thalamus, a major site of post-stroke SND. Our findings show that microglia process extension toward laser damage within the thalamus is lost, yet remains robustly intact within the PI territory. However, microglia at both sites displayed an activated morphology and elevated levels of commonly used activation markers (CD68, CD11b), indicating that the standardly used fixed tissue metrics of microglial activity are not necessarily predictive of microglia function. Analysis of the purinergic P2Y12 receptor, a key regulator of microglia process extension, revealed an increased somal localization on nonresponsive microglia in the thalamus. To our knowledge, this is the first study to identify a non-responsive microglia phenotype specific to areas of SND post-stroke, which cannot be identified by the classical assessment of microglia activation but rather the localization of P2Y12 to the soma.

    Original languageEnglish
    Pages (from-to)1885-1899
    Number of pages15
    JournalGlia
    Volume65
    Issue number12
    DOIs
    Publication statusPublished - Dec-2017

    Keywords

    • laser injury
    • live cell multiphoton imaging
    • P2Y12 receptor
    • peri-infarct
    • thalamus
    • IN-VIVO
    • MOTOR CORTEX
    • BRAIN-INJURY
    • RAT-BRAIN
    • ACTIVATION
    • STROKE
    • RECEPTOR
    • ATP
    • P2Y(12)
    • DAMAGE

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