Immunoglobulin G4-related sialadenitis (IgG4-RS) is an immune-mediated fibro-inflammatory disease and the pathogenesis is still not fully understood. The aim of this study was to explore the role and mechanism of interleukin-13 (IL-13) in the cellular senescence during the progress of IgG4-RS. We found that the expression of IL-13 and IL-13 receptor α1 (IL-13Rα1) as well as the number of senescent cells were significantly higher in the submandibular glands (SMGs) of IgG4-RS patients. IL-13 directly induced senescence as shown by the elevated activity of senescence-associated β-galactosidase (SA-β-gal), the decreased cell proliferation, and the upregulation of senescence markers (p53 and p16) and senescence-associated secretory phenotype (SASP) factors (IL-1β and IL-6) in SMG-C6 cells. Mechanistically, IL-13 increased the level of phosphorylated signal transducer and activator of transcription 6 (p-STAT6) and mitochondrial-reactive oxygen species (mtROS), while decreased the mitochondrial membrane potential, ATP level, and the expression and activity of superoxide dismutase 2 (SOD2). Notably, the IL-13-induced cellular senescence and mitochondrial dysfunction could be inhibited by pretreatment with either STAT6 inhibitor AS1517499 or mitochondria-targeted ROS scavenger MitoTEMPO. Moreover, IL-13 increased the interaction between p-STAT6 and cAMP-response element binding protein (CREB)-binding protein (CBP) and decreased the transcriptional activity of CREB on SOD2. Taken together, our findings revealed a critical role of IL-13 in the induction of salivary gland epithelial cell senescence through the elevated mitochondrial oxidative stress in a STAT6-CREB-SOD2-dependent pathway in IgG4-RS.
Cellular Senescence/genetics* ; Humans ; Immunoglobulin G/metabolism* ; Interleukin-13/pharmacology* ; Mitochondria/metabolism* ; Sialadenitis/metabolism*

OBJECTIVETo analyze the clinicopathologic features of chronic sclerosing submaxillaritis (CSS).

METHODSThe clinical and pathological characteristics of 9 CSS were analyzed.

RESULTSIn the 9 patients, there were 6 males and 3 females. The age of patients ranged from 51 - 77 years old. All of the tumors were located in the submandibular gland, presenting with painless and firm mass. Histologically, a well-defined mass lesion with extensive lymphocytes and plasma cells infiltration, preservation of lobular architecture, with acinar atrophy. The reactive hyperplasia of lymphoid follicles may be found in CSS. The phlebitis and obliterating phlebitis also formed. Immunohistochemistry showed evidence of diffuse infiltration of plasma cells. The mean number of IgG4-positive plasma cell per high-power field (HPF) was 186, mean value of the IgG4:IgG ratio was 0.71. Three of these 9 cases had manifestations of IgG4-associated systemic disease.

CONCLUSIONSCSS is considered as a part of IgG4-related sclerosing diseases, recognition of which is very essential for a successful treatment. When diagnosis is made, it is necessary to ascertain whether lesion occurs within salivary gland only or in combination with outside IgG4-related sclerosing disease. The establishment of follow-up is also necessary. Some patients show good response to steroid therapy.

Aged ; Female ; Humans ; Immunoglobulin G ; metabolism ; Male ; Middle Aged ; Plasma Cells ; immunology ; Sclerosis ; Sialadenitis ; metabolism ; surgery ; Submandibular Gland ; pathology ; surgery