Autoimmune rheumatologic diseases
Systemic lupus erythematosus is an autoimmune disease characterized by chronic inflammation. We have previously shown that TLR7 and TLR8 are significantly upregulated in PBMCs of Lupus patients. Recent studies have discovered that miR-21, mir-29a, and miR-29b packaged and secreted in extracellular vesicles (EVs) can also bind to these receptors.
Lupus patients meeting revised ACR guidelines and healthy controls provided informed consent to participate in this IRB-approved study. Plasma-derived EVs were isolated by differential ultracentrifugation and validated by Nanosight and ELISA. A novel human-mouse chimeric model of Lupus was created by adoptively transferring Lupus PBMCs into immunodeficient mouse recipients. Prior to transfer, PBMCs were incubated with synthetic liposomal EVs containing miR antagonists to miR-21, mir-29a, and miR-29b, or a control. After 21 days, PBMCs were collected for immunophenotyping and ELISA.
There was an upregulation of EVs found in the plasma of Lupus patients compared to healthy controls. RNAseq data resulted in a collection of statistically significant small RNA reads, such as miR-142-3p and let-7b-5p. Human CD4+, CD8+, B-cells, monocytes, and NK cells were successfully recovered from whole blood of chimeric mice at similar levels, but levels of human IL-2, IL-6, IL-10, and TNF-α were reduced with miR inhibition. Moreover, miR inhibition significantly reduced histopathology in the small intestine, liver, and kidney, demonstrated by H&E and human CD3 immunohistochemistry.
Our data shows elevated levels of EVs in Lupus patients and reveals unique EV-derived small RNA signatures that may be targeted therapeutically or used as diagnostic biomarkers for Lupus.