Interferon gamma and tumor necrosis factor alpha induce Fas expression and anti-Fas mediated apoptosis in a salivary ductal cell line.
BACKGROUND
We previously reported that Fas antigen was strongly expressed on salivary duct epithelial cells and that some salivary infiltrating cells showed the Fas ligand in patients with severe sialoadenitis due to Sjögren's syndrome (SS). Apoptotic changes were observed in ductal epithelial cells and some infiltrating cells by DNA nick end labeling methods. These findings suggest that the Fas-Fas ligand system may play a role in the pathogenesis of sialoadenitis in SS.


OBJECTIVE
To elucidate the mechanism of the de novo expression of ductal Fas antigen in sialoadenitis associated with SS, we investigated the induction of Fas antigen and apoptosis by cytokines in a human salivary duct cell line.


METHODS
Human salivary duct cell line (HSG) was cultured with interferon gamma (IFN-gamma), tumor necrosis factor alpha (TNF-alpha), interleukin 1 beta (IL-1 beta), interleukin 2 (IL-2), interleukin 4 (IL-4), and granulocyte monocyte colony stimulating factor (GM-CSF). The expression of Fas antigen in HSG was examined by immunoperoxidase cell ELISA. The appearance of DNA strand breaks during apoptosis induced by anti-Fas antibody was detected by DNA nick end labeling methods.


RESULTS
Unstimulated HSG cells constitutively expressed low levels of Fas antigen. IFN-gamma and TNF-alpha consistently upregulated constitutive levels of Fas. In contrast, IL-1 beta, IL-2, IL-4, and GM-CSF had no effect on Fas levels. HSG cells expressing Fas antigen in response to IFN-gamma or TNF-alpha were susceptible to apoptosis by anti-Fas antibody.


CONCLUSIONS
Our findings suggest that IFN-gamma or TNF-alpha secreted by infiltrating lymphocytes induces ductal Fas expression and ductal apoptosis in sialoadenitis associated with SS.
Matsumura
R
R
Department of Internal Medicine, Toho University School of Medicine, Sakura Hospital, Japan.
Umemiya
K
K
Goto
T
T
Nakazawa
T
T
Ochiai
K
K
Kagami
M
M
Tomioka
H
H
Tanabe
E
E
Sugiyama
T
T
Sueishi
M
M
D000970:Antineoplastic Agents / Q000276:immunology / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology*; D002460:Cell Line; D004847:Epithelial Cells / Q000737:chemistry / Q000166:cytology / Q000187:drug effects; D005455:Fluorescent Antibody Technique; D016178:Granulocyte-Macrophage Colony-Stimulating Factor / Q000494:pharmacology; D006801:Humans; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G / Q000494:pharmacology; D007371:Interferon-gamma / Q000276:immunology / Q000494:pharmacology*; D007375:Interleukin-1 / Q000494:pharmacology; D007376:Interleukin-2 / Q000494:pharmacology; D015847:Interleukin-4 / Q000494:pharmacology; D008199:Lymphadenitis / Q000276:immunology / Q000473:pathology; D009500:Neutralization Tests; D018987:Salivary Ducts / Q000166:cytology*; D012859:Sjogren's Syndrome / Q000276:immunology / Q000473:pathology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D019014:fas Receptor / Q000032:analysis / Q000096:biosynthesis*
D000970:Antineoplastic Agents; D007074:Immunoglobulin G; D007375:Interleukin-1; D007376:Interleukin-2; D014409:Tumor Necrosis Factor-alpha; D019014:fas Receptor; D015847:Interleukin-4; D007371:Interferon-gamma; D016178:Granulocyte-Macrophage Colony-Stimulating Factor