High Levels of Saturated Fatty Acids may Exacerbate the Pathogenesis of Primary Sjögren’s Syndrome

Abstract

Obesity and type 2 diabetes (T2D) are characterized by decreased insulin sensitivity and higher concentrations of free fatty acids (FFAs) in the serum. Among FFAs, saturated fatty acids, such as palmitate, have been reported to play a role in obesity-associated inflammation. Primary Sjögren’s syndrome (SS) is an autoimmune disease characterized by infiltration of inflammatory mononuclear cells and destruction of epithelial cells in salivary and lacrimal glands. Although epidemiological studies have suggested a link between primary SS and dyslipidemia or T2D, little is known about the clinical significance of elevated serum level of FFAs in primary SS. In salivary gland epithelial cells of patients with primary SS, interleukin (IL)-6 production and α-fodrin degradation are increased. IL-6 is one of the pro-inflammatory cytokines, and the cleavaged α-fodrin serves as an auto-antigen. In this study, we demonstrate that palmitate, but not unsaturated fatty acids, induces IL-6 production and α-fodrin degradation in human salivary gland epithelial cell lines. However, palmitate did not induce these responses in keratinocytes. Taken together, these results suggest that higher levels of saturated fatty acids may promote the severity of primary SS.