Discovery of a CXCR4 agonist pepducin that mobilizes bone marrow hematopoietic cells.
The G protein-coupled receptor (GPCR), chemokine CXC-type receptor 4 (CXCR4), and its ligand, CXCL12, mediate the retention of polymorphonuclear neutrophils (PMNs) and hematopoietic stem and progenitor cells (HSPCs) in the bone marrow. Agents that disrupt CXCL12-mediated chemoattraction of CXCR4-expressing cells mobilize PMNs and HSPCs into the peripheral circulation and are therapeutically useful for HSPC collection before autologous bone marrow transplantation (ABMT). Our aim was to develop unique CXCR4-targeted therapeutics using lipopeptide GPCR modulators called pepducins. A pepducin is a synthetic molecule composed of a peptide derived from the amino acid sequence of one of the intracellular (IC) loops of a target GPCR coupled to a lipid tether. We prepared and screened a small CXCR4-targeted pepducin library and identified several pepducins with in vitro agonist activity, including ATI-2341, whose peptide sequence derives from the first IC loop. ATI-2341 induced CXCR4- and G protein-dependent signaling, receptor internalization, and chemotaxis in CXCR4-expressing cells. It also induced dose-dependent peritoneal recruitment of PMNs when administered i.p. to mice. However, when administered systemically by i.v. bolus, ATI-2341 acted as a functional antagonist and dose-dependently mediated release of PMNs from the bone marrow of both mice and cynomolgus monkeys. ATI-2341-mediated release of granulocyte/macrophage progenitor cells from the bone marrow was confirmed by colony-forming assays. We conclude that ATI-2341 is a potent and efficacious mobilizer of bone marrow PMNs and HSPCs and could represent a previously undescribed therapeutic approach for the recruitment of HSPCs before ABMT.
Anchor Therapeutics, Cambridge, MA 02142, USA.
Boris
B
Tchernychev
Yong
Y
Ren
Pallavi
P
Sachdev
Jay M
JM
Janz
Lynn
L
Haggis
Adam
A
O'Shea
Ed
E
McBride
Richard
R
Looby
Qing
Q
Deng
Thomas
T
McMurry
Manija A
MA
Kazmi
Thomas P
TP
Sakmar
Stephen
S
Hunt
Kenneth E
KE
Carlson
D000818:Animals; D002633:Chemotaxis / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D057809:HEK293 Cells; D019650:Hematopoietic Stem Cell Mobilization; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000378:metabolism; D008252:Macaca fascicularis; D051379:Mice; D008807:Mice, Inbred BALB C; D010455:Peptides / Q000494:pharmacology*; D019718:Receptors, CXCR4 / Q000819:agonists* / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*
C527276:CXCR4 protein, human; C514936:CXCR4 protein, mouse; D010455:Peptides; D019718:Receptors, CXCR4