The peptidylarginine deiminases PAD2 and PAD4 are implicated in the pathogenesis of several autoimmune diseases. PAD4 may be pathogenic in systemic lupus erythematosus (SLE) through its role in neutrophil extracellular trap (NET) formation that promotes autoantigen externalization, immune dysregulation, and organ damage. The role of this enzyme in mouse models of autoimmunity remains unclear, as pan-PAD chemical inhibitors improve clinical phenotype, whereas PAD4-KO models have given conflicting results. The role of PAD2 in SLE has not been investigated. The differential roles of PAD2 and PAD4 in TLR-7–dependent lupus autoimmunity were examined. Padi4–/– displayed decreased autoantibodies, type I IFN responses, immune cell activation, vascular dysfunction, and NET immunogenicity. Padi2–/– mice showed abrogation of Th subset polarization, with some disease manifestations reduced compared with WT but to a lesser extent than Padi4–/– mice. RNA sequencing analysis revealed distinct modulation of immune-related pathways in PAD-KO lymphoid organs. Human T cells express both PADs and, when exposed to either PAD2 or PAD4 inhibitors, displayed abrogation of Th1 polarization. These results suggest that targeting PAD2 and/or PAD4 activity modulates dysregulated TLR-7–dependent immune responses in lupus through differential effects of innate and adaptive immunity. Compounds that target PADs may have potential therapeutic roles in T cell–mediated diseases.
Yudong Liu, Yaíma L. Lightfoot, Nickie Seto, Carmelo Carmona-Rivera, Erica Moore, Rishi Goel, Liam O’Neil, Pragnesh Mistry, Victoria Hoffmann, Santanu Mondal, Padmavathy Nandha Premnath, Katherine Gribbons, Stefania Dell’Orso, Kan Jiang, Paul R. Thompson, Hong-Wei Sun, Scott A. Coonrod, Mariana J. Kaplan
Usage data is cumulative from December 2018 through December 2018.
Usage information is collected from two different sources: this site (JCI) and Pubmed Central (PMC). JCI information (compiled daily) shows human readership based on methods we employ to screen out robotic usage. PMC information (aggregated monthly) is also similarly screened of robotic usage.
Various methods are used to distinguish robotic usage. For example, Google automatically scans articles to add to its search index and identifies itself as robotic; other services might not clearly identify themselves as robotic, or they are new or unknown as robotic. Because this activity can be misinterpreted as human readership, data may be re-processed periodically to reflect an improved understanding of robotic activity. Because of these factors, readers should consider usage information illustrative but subject to change.