Role of cytotoxic protease granzyme-b in neuronal degeneration during human stroke

Ganta Vijay Chaitanya, Prabhakar Eeka, Reinhold Munker, Jonathan Steven Alexander, Phanithi Prakash Babu

Research output: Contribution to journalArticlepeer-review

27 Scopus citations

Abstract

Infiltration of leukocytes into post-ischemic cerebrum is a well-described phenomenon in stroke injury. Because CD-8+ T-lymphocytes secrete cytotoxic proteases, including granzyme-b (Gra-b) that exacerbates post-ischemic brain damage, we investigated roles of Gra-b in human stroke. To study the role of Gra-b in stroke, ischemic and non-ischemic tissues (from post-mortem stroke patients) were analyzed using immunoblotting, co-immunoprecipitation, terminal deoxy uridine nick end labeling (TUNEL) and Annexin-V immunostaining, and in vitro neuron survival assays. Activated CG-SH cells and supernatants were used to model leukocyte-dependent injury. Non-ischemic brain tissues were used as non-pathological controls. Non-activated CG-SH cells and supernatants were used as controls for in vitro experiments. Human stroke (ischemic) samples contained significantly higher levels of Gra-b and interferon-gamma inducible protein-10 (IP-10/CXCL10) than non-ischemic controls. In stroke, poly (ADP-ribose) polymerase-1 and heat shock protein-70 were cleaved to canonical proteolytic "signature" fragments by Gra-b. Gra-b was also found to bind to Bid and caspase-3. Gra-b also co-localized with Annexin-V+/TUNEL + in degenerating neurons. Importantly, Gra-b inhibition protected both normal and ischemia-reperfused neurons against in vitro neurotoxicity mediated by activated CG-SH cells and supernatants. These results suggest that increased leukocyte infiltration and elevated Gra-b levels in the post-stroke brain can induce contact-dependent and independent post-ischemic neuronal death to aggravate stroke injury.

Original languageEnglish (US)
Pages (from-to)16-30
Number of pages15
JournalBrain Pathology
Volume21
Issue number1
DOIs
StatePublished - Jan 2011
Externally publishedYes

Keywords

  • apoptosis-inducing factor
  • heat shock protein-70
  • Myeloid leukemia cell differentiation protein-1
  • poly (ADP-ribose) polymerase-1
  • terminal deoxy uridine nick end labeling

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Neuroscience(all)
  • Clinical Neurology

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