RESUMO
OBJECTIVE: Systemic lupus erythematosus (SLE) affects nine women to every man worldwide, and these patients are at greater risk for cardiovascular disease (CVD) morbidity and mortality. Clinical studies have demonstrated that patients with SLE are more likely to develop CVD, including cardiac and vascular dysfunction. Although many preclinical models of SLE are available, including treatment with Toll-like receptor (TLR) 7/8 agonists, a consistent preclinical model of SLE-like CVD with systemic, cardiac, renal, and cerebral endothelial activation and cardiac dysfunction has yet to be described. Here, we hypothesize that acceleration of SLE with the TLR7/8 agonist resiquimod (R848) will promote cardiac and endothelial activation with subsequent end-stage organ damage in the SLE-prone B6.Nba2 mouse model. METHODS: Female and male SLE-prone B6.Nba2 mice were treated with R848 or acetone, administered topically twice weekly over a four-week period, to accelerate the development of SLE-like pathophysiology. Echocardiography was performed at baseline, 4 weeks, and 16 weeks. At 16 weeks, tissues were harvested, weighed, and analyzed by histology, immunofluorescence, real-time quantitative polymerase chain reaction, and enzyme-linked immunosorbent assays. RESULTS: We found that female R848-treated mice had increased serum anti-Smith and immunoglobulin G complex deposition in the kidney, heart, and brain consistent with SLE-like etiology. Tissue analysis revealed significant enlargement of the spleen in both female and male R848-treated mice, with only cardiac and renal enlargement in females compared to their respective controls. Echocardiographic imaging revealed left ventricular wall thickening by 4 weeks that was followed by a progressive increase in left ventricular internal diameters and subsequent decrease in ejection fraction over the 16-week time course in female mice. We found that circulating levels of soluble vascular adhesion molecule-1 and soluble intracellular adhesion molecule-1 were increased in both female and male R848-treated mice, whereas cardiac and renal fibrosis were significantly increased in only female R848-treated mice. CONCLUSION: Our data demonstrate that R848 treatment of SLE-prone B6.Nba2 mice is a novel preclinical model to study the sex-dependent pathophysiologic mechanisms of SLE-like CVD.
RESUMO
Increased mechanical endothelial cell stretch contributes to the development of numerous cardiovascular and renal pathologies. Recent studies have shone a light on the importance of sex-dependent inflammation in the pathogenesis of renal disease states. The endothelium plays an intimate and critical role in the orchestration of immune cell activation through upregulation of adhesion molecules and secretion of cytokines and chemokines. While endothelial cells are not recognized as professional antigen-presenting cells, in response to cytokine stimulation, endothelial cells can express both major histocompatibility complex (MHC) I and MHC II. MHCs are essential to forming a part of the immunological synapse interface during antigen presentation to adaptive immune cells. Whether MHC I and II are increased under increased mechanical stretch is unknown. Due to hypertension being multifactorial, we hypothesized that increased mechanical endothelial stretch promotes the regulation of MHCs and key costimulatory proteins on mouse renal endothelial cells (MRECs) in a stretch-dependent manner. MRECs derived from both sexes underwent 5%, 10%, or 15% uniaxial cyclical stretch, and immunological synapse interface proteins were determined by immunofluorescence microscopy, immunoblot analysis, and RNA sequencing. We found that increased endothelial mechanical stretch conditions promoted downregulation of MHC I in male MRECs but upregulation in female MRECs. Moreover, MHC II was upregulated by mechanical stretch in both male and female MRECs, whereas CD86 and CD70 were regulated in a sex-dependent manner. By bulk RNA sequencing, we found that increased mechanical endothelial cell stretch promoted differential gene expression of key antigen processing and presentation genes in female MRECs, demonstrating that females have upregulation of key antigen presentation pathways. Taken together, our data demonstrate that mechanical endothelial stretch regulates endothelial activation and immunological synapse interface formation in renal endothelial cells in a sex-dependent manner.NEW & NOTEWORTHY Endothelial cells contribute to the development of renal inflammation and have the unique ability to express antigen presentation proteins. Whether increased endothelial mechanical stretch regulates immunological synapse interface proteins remains unknown. We found that antigen presentation proteins and costimulatory proteins on renal endothelial cells are modulated by mechanical stretch in a sex-dependent manner. Our data provide novel insights into the sex-dependent ability of renal endothelial cells to present antigens in response to endothelial mechanical stimuli.