Vesicle-associated membrane protein 7 (VAMP-7) is essential for target cell killing in a natural killer cell line.
Biochem Biophys Res Commun
; 366(3): 617-23, 2008 Feb 15.
Article
in En
| MEDLINE
| ID: mdl-18042464
ABSTRACT
Natural killer cells recognize and induce apoptosis in foreign, transformed or virus-infected cells through the release of perforin and granzymes from secretory lysosomes. Clinically, NK-cell mediated killing is a major limitation to successful allo- and xenotransplantation. The molecular mechanisms that regulate the fusion of granzyme B-containing secretory lysosomes to the plasma membrane in activated NK cells, prior to target cell killing, are not fully understood. Using the NK cell line YT-Indy as a model, we have investigated the expression of SNAP REceptors (SNAREs), both target (t-) and vesicular (v-) SNAREs, and their function in granzyme B-mediated target cell killing. Our data showed that YT-Indy cells express VAMP-7 and SNAP-23, but not VAMP-2. VAMP-7 was associated with granzyme B-containing lysosomal granules. Using VAMP-7 small interfering RNA (siRNA), we successfully knocked down the expression of VAMP-7 protein in YT-Indy to less than 10% of untreated cells in 24h. VAMP7-deficient YT-Indy cells activated via co-culture with Jurkat cells released <1ng/mL of granzyme B, compared to 1.5-2.5 microg/mL from controls. Using Jurkat cells as targets, we showed a 7-fold reduction in NK cell-mediated killing by VAMP-7 deficient YT-Indy cells. Our results show that VAMP-7 is a crucial component of granzyme B release and target cell killing in the NK cell line YT-Indy. Thus, targeting VAMP-7 expression specifically with siRNA, following transplantation, may be a viable strategy for preventing NK cell-mediated transplant rejection, in vivo.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Killer Cells, Natural
/
Apoptosis
/
SNARE Proteins
/
R-SNARE Proteins
/
Granzymes
Type of study:
Prognostic_studies
/
Risk_factors_studies
Limits:
Humans
Language:
En
Journal:
Biochem Biophys Res Commun
Year:
2008
Type:
Article
Affiliation country:
Canada