Expression of cytokines by human astrocytomas following stimulation by C3a and C5a anaphylatoxins: specific increase in interleukin-6 mRNA expression.
C3a and C5a anaphylatoxins are two proinflammatory peptides generated during complement activation that act through distinct Gi protein-coupled receptors named C3aR and C5aR, respectively. We have demonstrated previously that human astrocytes expressed C3aR and C5aR constitutively and were able to produce a functional complement. In this study, we examined the effect of an anaphylatoxin stimulation on cytokine expression by human astrocyte cell lines. Interleukin (IL)-1beta, IL-6, tumor necrosis factor-alpha, and transforming growth factor-beta mRNA expression was studied by quantitative RT-PCR. Whereas IL-1beta, tumor necrosis factor-alpha, and transforming growth factor-beta mRNA levels remained unchanged, stimulation of astrocytoma cells (T98G, CB193, U118MG) by C3a, C5a, and peptidic C3aR and C5aR agonists induced an increase in the IL-6 mRNA level. The amount of IL-6 was markedly increased at 3 and 6 h and returned to the basal level at 9 h of stimulation. This response was specific, because pretreatment of cells with pertussis toxin or with polyclonal anti-C3aR or anti-C5aR antibodies completely blocked the IL-6 mRNA increase. The IL-6 response was also investigated at the protein level, but IL-6 protein was detected neither in cell lysates nor in supernatants of stimulated cells. The anaphylatoxin-mediated transcriptional activation of IL-6 gene suggests that C3a and C5a could play a role in priming glial cells during the inflammatory process in the brain.
Sayah
S
S
Institut Fédératif de Recherche Multidisciplinaire sur les Peptides no. 23, INSERM U78, Faculté Mixte de Médecine et Pharmacie, Rouen, France.
Ischenko
A M
AM
Zhakhov
A
A
Bonnard
A S
AS
Fontaine
M
M
D000706:Anaphylatoxins / Q000494:pharmacology / Q000502:physiology; D000906:Antibodies / Q000494:pharmacology; D015703:Antigens, CD / Q000502:physiology; D001254:Astrocytoma / Q000276:immunology*; D015926:Complement C3a / Q000494:pharmacology / Q000502:physiology*; D015936:Complement C5a / Q000494:pharmacology / Q000502:physiology*; D016207:Cytokines / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000276:immunology*; D006801:Humans; D007375:Interleukin-1 / Q000235:genetics; D015850:Interleukin-6 / Q000235:genetics*; D007700:Kinetics; D008565:Membrane Proteins; D037342:Pertussis Toxin; D012333:RNA, Messenger / Q000235:genetics; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors; D014158:Transcription, Genetic / Q000187:drug effects / Q000276:immunology*; D016212:Transforming Growth Factor beta / Q000235:genetics; D014407:Tumor Cells, Cultured; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D000706:Anaphylatoxins; D000906:Antibodies; D015703:Antigens, CD; D016207:Cytokines; D007375:Interleukin-1; D015850:Interleukin-6; D008565:Membrane Proteins; D012333:RNA, Messenger; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement; D016212:Transforming Growth Factor beta; D010566:Virulence Factors, Bordetella; C085567:complement C3a receptor; D015926:Complement C3a; D015936:Complement C5a; D037342:Pertussis Toxin