Regulation of MMP9 transcription by ETS1 in immortalized salivary gland epithelial cells of patients with salivary hypofunction and primary Sjögren’s syndrome

Abstract

Primary Sjögren’s syndrome (pSS) patients exhibit enhanced degradation of the salivary epithelium initially through MMP9 overexpression. We assessed the expression of MMP9 and an associated transcription factor, ETS1, in primary salivary gland epithelial cells (SGECs) and investigated potential regulatory mechanism(s) in immortalized SGECs. SGECs and iSGECs were derived from pSS and/or xerostomic “sicca” patients. siRNA knockdown of ETS1 in iSGECs was performed to determine MMP9 mRNA (qRT-PCR) and protein expression (ELISA). ETS1 binding to MMP9 promoter was assessed by luciferase activity and binding confirmed by mutagenesis and ChIP. Effects of ETS1 overexpression on progenitor and Epithelial-Mesenchymal transition (EMT) associated markers were determined by Western blot. Expression of ETS1 and its phosphorylated form in iSGECs was determined by immunofluorescence microscopy. ETS1 and MMP9 were overexpressed in SGECs of pSS and non-pSS sicca patients with salivary gland lymphocytic infiltration compared to non-pSS sicca patients without infiltration. ETS1 siRNA knockdown reduced both MMP9 mRNA and protein levels. ETS1 overexpression affected the expression of EMT and progenitor cell markers. Lastly, ETS1 bound the MMP9 promoter within the DNA region of −296 bp to −339 bp. ETS1 may impair salivary function through direct transcriptional control of the MMP9 promoter. ETS1 upregulation may also affect other factors involved in repair of the dysfunctional pSS salivary epithelium.

Network pharmacology and molecular docking analysis on the mechanism of Tripterygium wilfordii Hook in the treatment of Sjögren syndrome

“…In patients with pSS, acinar and ductal cells have been shown to be responsible for local MMP9 secretion. [ 19 ] Furthermore, the glandular expression and activity of MMP9 are highly correlated with the degree and severity of salivary gland damage and functional alterations. [ 20 ] Interestingly, MMP9 expression was significantly decreased in mice with lung cancer treated with nobiletin.…”

Bioinformatics analyses of potentially common pathogenic networks for primary Sjogren’s syndrome complicated with acute myocardial infarction

“…MMP9 enhances new blood vessel formation by increasing smooth muscle migration and VEGF release, which eventually weakens the ber cap by degrading ECM, while simultaneously enhancing in ammatory response by increasing monocytes/macrophages swelling, which strongly diminishes plaque stability, thereby encouraging thrombosis formation [27][28][29]. Clinical trials revealed that the MMP-9 content in the salivary and lacrimal glands of pSS patients are strongly enhanced [30].…”

Involvement of Epithelial-Mesenchymal Transition (EMT) in Autoimmune Diseases

“…More recently, ETS1 and MMP9 were found to be overexpressed in SGECs from patients with pSS. Further functional analysis demonstrated that ETS1 directly induced expression of MMP9 by exercising its TF activity and affected the expression of EMT markers in immortalized SGECs (iSGECs) from pSS [195]. In addition, the presence of EMT in SGEC from pSS patients was further strengthened by RNA sequencing data showing an over-representation of a pathway involving MMPs (collagen type III Alpha 1 chain (COL3A1), COL1A2 and A Disintegrin And Metalloproteinase with Thrombospondin Motifs (ADAMTS)) and core-EMT TF such as ZEB2 (Table 2) [196].…”