download report - Istituto Pasteur

A. Santoni - Molecular mechanism underlying the activation of NK cell regulatory and effector functions
CD18 neoactivation epitope expression upon
chemokine stimulation. Similar results were also
obtained when NK cells from normal donors were
pretreated with wiskostatin, a specific pharmacological
inhibitor of Cdc42 interaction with
WASp/N-WASp family members, and then assayed
for the expression of the CD18 neoactivation epitope
upon chemokine stimulation. Pretreatment of
normal donor NK cells with wiskostatin also resulted
in a significant inhibition of integrin-supported
NK cell response to chemokines.
All together these data indicate that WASp plays a
crucial role in the regulation of NK cell response to
chemokines by acting as a critical component of the
chemokine-induced inside-out signaling regulating
LFA-1 function and suggest that upon integrin or
chemokine receptor engagement WASp function is
regulated by the coordinate action of both Cdc42 and
tyrosine kinases.
A paper contaning these information is in preparation
(Gismondi et al.).
The analysis of the role of chemokines on NK
cell functional maturation and trafficking in
the BM
In regard to this task, we focused our attention on
understanding the chemokine involvement in the
selective trafficking of developing and mature
mouse NK cells in the BM. We observed drastic
changes of CCR1, CXCR3 and CXCR4 expression
during the progression from NK cell precursors
(pNK) to immature DX5- (iNK) and mature DX5+
(mNK) NK cells. pNK and mNK cells expressed all
receptors, while only CXCR4 was detected on iNK
cells. Correspondingly, mNK cells migrated in
response to CXCL12, CXCL10 and CCL3, and
pNK and iNK cells to CXCL12, while pNK cells
migrated to CCL3 and CXCL10 only after
CXCL12 stimulation.
102
When compared to BM mNK cells, spleen and
peripheral blood mNK cells differently expressed
CXCR4 and CXCR3 and were less responsive to
chemokines. CXCR4 antagonist AMD-3100 administration
to C57BL/6 mice promoted strong reduction
of mNK and iNK cell numbers in BM and their
increase in blood and spleen, while pNK cell distribution
slightly varied. Recombinant CCL3 administration
selectively mobilized mNK cells and this correlated
with its ability to inhibit CXCL12-mediated
mNK cell in vitro responses.
Our results indicate that the combined action of
chemokines may regulate selective localization of
NK cell subsets in the BM and direct their maturation
and migration to the periphery. In addition,
understanding how NK cells are mobilized from BM
could assist the development of novel NK cell-based
immunotherapy for cancer and chronic infections.
A paper containing these results has been published
in Blood 2008, 111:3626-34.
Selected publications
Cerboni C, Zingoni A, Cippitelli M, Piccoli M, Frati
L, Santoni A. Antigen-activated human T lymphocytes
express cell-surface NKG2D ligands via an
ATM/ATR-dependent mechanism and become susceptible
to autologous NK- cell lysis. Blood 2007,
110:606-15.
Bernardini G, Sciumè G, Bosisio D, Morrone S,
Sozzani S, Santoni A. CCL3 and CXCL12 regulate
trafficking of mouse bone marrow NK cell subsets.
Blood 2008, 111:3626-34.
Micucci F, Capuano C, Marchetti E, Piccoli M, Frati
L, Santoni A, Galandrini R. PI5KI-dependent signals
are critical regulators of the cytolytic secretory
pathway. Blood 2008, 111:4165-72.