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Ductal cells of minor salivary glands in Sjögren's syndrome express LINE‐1 ORF 2p and APOBEC 3B
Author(s) -
Kalogirou EleniMarina,
Piperi Evangelia P.,
Tosios Konstantinos I.,
Tsiambas Evangelos,
Fanourakis Galinos,
Sklavounou Alexandra
Publication year - 2018
Publication title -
journal of oral pathology and medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.887
H-Index - 83
eISSN - 1600-0714
pISSN - 0904-2512
DOI - 10.1111/jop.12656
Subject(s) - immunohistochemistry , salivary gland , pathology , apobec , immunostaining , biology , immunology , microbiology and biotechnology , medicine , endocrinology , apolipoprotein b , cholesterol
Background Type I interferon activation is a hallmark event in Sjögren's syndrome. L1 retroelements stimulate plasmacytoid dendritic cells, activating the type I interferons, and are regulated by various mechanisms, including the APOBEC 3 deaminases. As L1s are potential trigger factors in autoimmunity, we aimed to investigate the immunohistochemical localization of L1 ORF 2p and its inhibitor APOBEC 3B protein in minor salivary glands of Sjögren's syndrome patients. Methods Twenty minor salivary gland‐tissue samples from 20 Sjögren's syndrome patients, classified according to Tarpley's histological criteria, and 10 controls were evaluated for L1 ORF 2p and APOBEC 3B expression via immunohistochemistry. Results L1 ORF 2p was expressed in 17/20 SS patients and all controls. APOBEC 3B expression was observed in 15/20 Sjögren's syndrome patients, 5/5 chronic sialadenitis, and 3/5 normal minor salivary glands. Both antibodies stained the cytoplasm of the ductal epithelial cells. Negative staining was observed in the acinar cells. L1 ORF 2p‐positive immunostaining was significantly lower in Tarpley IV Sjögren's syndrome patients than controls ( P = .039), and APOBEC 3B‐positive staining was significantly lower in Tarpley I compared to Tarpley II Sjögren's syndrome patients ( P = .008) and controls ( P = .035). Conclusions L1 ORF 2p and APOBEC 3B are expressed in the ductal epithelial cells of minor salivary glands that are among the key targets in Sjögren's syndrome. L1 ORF 2p expression may promote the L1 ability to act as an intrinsic antigen in Sjögren's syndrome. The potential future use of L1 ORF 2‐reverse transcriptase inhibitors in autoimmunity supports further investigation of L1 epigenetic regulation by APOBEC 3 enzymes.