Pig MAP/ITIH4 and haptoglobin are interleukin-6-dependent acute-phase plasma proteins in porcine primary cultured hepatocytes.
The acute-phase expression of pig MAP (major acute-phase protein)/ITIH4 (inter-alpha-trypsin inhibitor heavy chain 4) and haptoglobin were analysed in primary cultures of isolated pig hepatocytes in response to recombinant human (rh) cytokines: tumor necrosis factor-alpha (TNF-alpha), interleukin-1 (IL-1), interleukin-6 (IL-6), as well as to bacterial lipopolysaccharide (LPS). Analysis of pig MAP/ITIH4 and haptoglobin mRNAs was carried out by RT-PCR amplification. Secreted proteins from the cytokine-treated hepatocytes were quantified by immunochemical techniques. Time-course and dose-response experiments show that pig MAP/ITIH4 and haptoglobin belong to the type II acute-phase proteins, as they are specifically induced by rhIL-6 and not by rhTNF-alpha or rhIL-1. Stimulation of cultured pig hepatocytes with rhIL-6 for 48 h at doses of 1000 U.mL-1 showed a fourfold to fivefold increase in pig MAP/ITIH4 concentration in the medium, while the concentration of haptoglobin only increased twofold. A similar increase in the concentration of pig MAP/ITIH4 was also observed in media of LPS-treated hepatocytes with the simultaneous generation of IL-6 by the Kupffer cells present in the cultures. Albumin secretion decreased after stimulation with doses of 100 or 1000 U.mL-1 rhTNF-alpha, rhIL-1 or rhIL-6. Therefore, it can be concluded that pig MAP/ITIH4 behaves as a major acute-phase protein produced by porcine hepatocytes under the effect of inflammatory cytokines.
González-Ramón
N
N
Departamento de Bioquímica y Biología Molecular y Celular, Universidad de Zaragoza, Spain.
Hoebe
K
K
Alava
M A
MA
Van Leengoed
L
L
Piñeiro
M
M
Carmona
S
S
Iturralde
M
M
Lampreave
F
F
Piñeiro
A
A
D000209:Acute-Phase Proteins / Q000096:biosynthesis* / Q000235:genetics; D000210:Acute-Phase Reaction / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D002478:Cells, Cultured / Q000187:drug effects; D018076:DNA, Complementary / Q000235:genetics; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000187:drug effects*; D006242:Haptoglobins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D015850:Interleukin-6 / Q000494:pharmacology; D007728:Kupffer Cells / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008969:Molecular Sequence Data; D012333:RNA, Messenger / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013552:Swine; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
D000209:Acute-Phase Proteins; D018076:DNA, Complementary; D006242:Haptoglobins; D007375:Interleukin-1; D015850:Interleukin-6; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; C095815:ITIH4 protein, Sus scrofa