The growth-related gene product beta induces sphingomyelin hydrolysis and activation of c-Jun N-terminal kinase in rat cerebellar granule neurones.
The growth-related gene product beta (GRObeta) is a small chemoattractant cytokine that belongs to the CXC chemokine family, and GRObeta receptors are expressed in the brain, including the cerebellum. We demonstrate that rat cerebellar granule neurones express the GRObeta receptor CXCR2. We also show that, in addition to the known stimulation of a phosphoinositide-specific phospholipase C, GRObeta activates both neutral (N-) and acidic (A-) sphingomyelinases (SMase) and the stress-activated c-Jun N-terminal kinase 1 (JNK1). Although both exogenous ceramide and bacterial SMase stimulate JNK1, GRObeta-induced JNK1 activation is an event probably independent of ceramide generated by A-SMase, since it is maintained in the presence of compounds that block A-SMase activity. This is the first report on the activation of the SMase pathway by chemokines.
Limatola
C
C
Dipartimento di Medicina Sperimentale e Patologia, Universita' di Roma La Sapienza, Roma, Italy. limatola@axrma.uniroma1.it
Mileo
A M
AM
Giovannelli
A
A
Vacca
F
F
Ciotti
M T
MT
Mercanti
D
D
Santoni
A
A
Eusebi
F
F
D000818:Animals; D002531:Cerebellum / Q000378:metabolism*; D019743:Chemokines, CXC; D002630:Chemotactic Factors / Q000235:genetics / Q000378:metabolism*; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D006133:Growth Substances / Q000235:genetics / Q000378:metabolism*; D006868:Hydrolysis; D036341:Intercellular Signaling Peptides and Proteins; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction; D013109:Sphingomyelins / Q000378:metabolism*
D019743:Chemokines, CXC; D002630:Chemotactic Factors; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D013109:Sphingomyelins; D048031:JNK Mitogen-Activated Protein Kinases; D020928:Mitogen-Activated Protein Kinases