Adamts18 Deficiency Causes Spontaneous SMG Fibrogenesis in Adult Mice

Abstract

Chronic sclerosing sialadenitis of the submandibular gland (also known as Küttner tumor) is characterized by concomitant swelling of the submandibular glands secondary to strong lymphocytic infiltration and fibrosis. The pathogenesis of this disease has been unclear, but it is associated with immune disorders. ADAMTS18 is a member of the ADAMTS superfamily of extracellular proteinases. In this study, we showed that Adamts18 is highly expressed in submandibular salivary gland (SMG) during embryonic development and decreases but is retained in adult SMG tissue in mice. Adamts18 deficiency led to reduced cleft formation and epithelial branching in embryonic SMG before embryonic day 15.5 in mice. No significant histologic changes in the later stages of branching or the morphology of SMG were detected in Adamts18−/− mice. However, Adamts18 deficiency causes spontaneous SMG fibrogenesis and fibrosis in adult mice. At 8 wk of age, Adamts18−/− mice began to manifest the first signs of pathologic changes of mild fibrosis and CD11b+ cell infiltration in SMG tissues. At ≥8 mo, all male and female Adamts18−/− mice developed unilateral or bilateral SMG scleroma that is similar to patients with chronic sclerosing sialadenitis of the submandibular gland. Adamts18−/− mice also showed secretory dysfunction and severe dental caries. Histologically, SMG scleroma is characterized by progressive periductal fibrosis, acinar atrophy, irregular duct ectasis, and dense infiltration of IgG-positive plasma cells. A significant infiltration of CD4+ T lymphocytes and CD11b+ monocytes and macrophages was also detected in the SMG scleroma of Adamts18−/− mice. The levels of TGF-β1, IL-6, and IL-33 were significantly increased in Adamts18−/− SMGs, which induces chronic inflammation and myofibroblast activation, ultimately leading to fibrosis. This study indicates that Adamts18 regulates the early branching morphogenesis of embryonic SMG and plays a role in protecting from spontaneous SMG fibrogenesis via modulating local inflammation, autoimmune reaction, and myofibroblast activation in adult mice.

The Mechanism and Role of ADAMTS Protein Family in Osteoarthritis

“…ADAMTS-16 promotes cardiac fibrosis and cardiac hypertrophy by activating the LAP-TGF-β signaling pathway through RRFR motifs, resulting in the cleavage of the LAP domain of LAP-TGF-β and the release of TGF-β [ 204 ]. ADAMTS-18 deficiency causes spontaneous submandibular salivary gland fibrogenesis and fibrosis in adult mice [ 205 ]. ADAMTS-1 is critical for kidney development, and lack of ADAMTS-1 may lead to renal fibrosis and dysplasia in mice [ 206 ].…”

ADAMTS18 deficiency associates extracellular matrix dysfunction with a higher risk of HER2-positive mammary tumorigenesis and metastasis

“…Tissue samples were collected, fixed in 10% neutral formalin, embedded into paraffin blocks, then sectioned and stained for hematoxylin and eosin (HE) and/or immunohistochemistry (IHC)/immunofluorescence (IF), as well as RNA in situ hybridization (ISH). For IHC and IF assays, slides were incubated with indicated primary antibodies (Additional file 1 : Table S1), followed by secondary antibodies and imaged under a microscope as previously described in detail [ 13 , 16 – 18 ]. For RNA ISH, target mRNA in mouse mammary gland was detected using a specific Adamts18 probe, as described previously [ 13 ].…”

“…Quantitative Real-Time RT-PCR (qRT-PCR), Sandwich ELISA, and Western blotting analysis were performed essentially as previously described in detail [ 13 , 16 – 18 ]. Briefly, for qRT-PCR, total RNA was extracted from mouse mammary tissues and qRT-PCR was performed using the StepOnePlus real-time PCR system.…”

“…Briefly, for qRT-PCR, total RNA was extracted from mouse mammary tissues and qRT-PCR was performed using the StepOnePlus real-time PCR system. The sequences of primers used in qRT-PCR have been described previously [ 13 , 16 – 18 ]. For Sandwich ELISA, mouse mammary tissues were dissected, weighted, and homogenized.…”

“…The proteins were separated by SDS–PAGE and then transferred to polyvinylidene difluoride (PVDF) membrane. After incubation with primary and secondary antibodies, immunoreactive bands were visualized using enhanced chemiluminescence (ECL) and qualified using ImageJ software, as described previously [ 13 , 16 – 18 ].…”