Complement gene expression is regulated by pro-inflammatory cytokines and the anaphylatoxin C3a in human tenocytes.
Interplay between complement factors, regulatory proteins, anaphylatoxins and cytokines could be involved in tendon healing and scar formation. The expression and regulation of complement factors by cytokines or anaphylatoxins are completely unclear in tendon. Hence, the gene expression of the anaphylatoxin receptors C3aR, C5aR and cytoprotective complement regulatory proteins (CRPs) was analysed in human tendon, cultured primary tenocytes and to directly compare the general expression level, additionally in human leukocytes. Time-dependent regulation of complement by cytokines and the anaphylatoxin C3a was assessed in cultured tenocytes. Gene expression of the anaphylatoxin receptors C3aR, C5aR and the CRPs CD46, CD55 and CD59 was detected in tendon, cultured tenocytes and leukocytes, whereas CD35 could only be found in tendon and leukocytes. Compared with cultured tenocytes, complement expression was higher in tendon and compared with leukocytes C3aR, C5aR, CD35 and CD55, but not CD46 and CD59 gene expression levels were lower in tendon. C3aR mRNA was up-regulated by both TNFα and C3a in cultured tenocytes in a time-dependent manner whereby C5aR gene expression was only induced by C3a. IL-6 or C3a impaired the CRP gene expression. C3a stimulation lead to an up-regulation of TNFα and IL-1β mRNA in tenocytes. Degenerated tendons revealed an increased C5aR and a reduced CD55 expression. The expression profile of the investigated complement components in tendon and cultured tenocytes clearly differed from that of leukocytes. Tenocytes respond to the complement split fragment C3a with CRP suppression and enhanced pro-inflammatory cytokine gene expression suggesting their sensitivity to complement activation.
Department for Special Orthopaedic, Trauma and Reconstructive Surgery, Charité-Universitätsmedizin, Campus Benjamin Franklin, Berlin, Germany.
Catharina
C
Busch
Georg
G
Girke
Benjamin
B
Kohl
Christiane
C
Stoll
Marion
M
Lemke
Senat
S
Krasnici
Wolfgang
W
Ertel
Sandeep
S
Silawal
Thilo
T
John
Gundula
G
Schulze-Tanzil
D000328:Adult; D018958:CD55 Antigens / Q000235:genetics / Q000276:immunology; D018957:CD59 Antigens / Q000235:genetics / Q000276:immunology; D003167:Complement Activation / Q000187:drug effects; D003176:Complement C3 / Q000276:immunology / Q000494:pharmacology*; D003239:Connective Tissue Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D053583:Interleukin-1beta / Q000276:immunology / Q000494:pharmacology; D015850:Interleukin-6 / Q000276:immunology / Q000494:pharmacology; D007963:Leukocytes, Mononuclear / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051916:Membrane Cofactor Protein / Q000235:genetics / Q000276:immunology; D009928:Organ Specificity; D061251:Primary Cell Culture; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000276:immunology; D044087:Receptor, Anaphylatoxin C5a / Q000235:genetics* / Q000276:immunology; D011951:Receptors, Complement / Q000235:genetics* / Q000276:immunology; D017463:Receptors, Complement 3b / Q000235:genetics / Q000276:immunology; D013710:Tendons / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000276:immunology / Q000494:pharmacology
C038245:C3 protein, human; C497857:CD46 protein, human; D018958:CD55 Antigens; D018957:CD59 Antigens; C509991:CR1 protein, human; D003176:Complement C3; C508600:IL6 protein, human; D053583:Interleukin-1beta; D015850:Interleukin-6; D051916:Membrane Cofactor Protein; D012333:RNA, Messenger; D044087:Receptor, Anaphylatoxin C5a; D011951:Receptors, Complement; D017463:Receptors, Complement 3b; D014409:Tumor Necrosis Factor-alpha; C051590:CD59 protein, human