Dopaminergic signalling limits suppressive activity and gut homing of regulatory T cells upon intestinal inflammation
MUCOSAL IMMUNOLOGY
Authors: Ugalde, Valentina; Contreras, Francisco; Prado, Carolina; Chovar, Ornella; Espinoza, Alexandra; Pacheco, Rodrigo
Abstract
Evidence from inflammatory bowel diseases (IBD) patients and animal models has indicated that gut inflammation is driven by effector CD4(+) T-cell, including Th1 and Th17. Conversely, Treg seem to be dysfunctional in IBD. Importantly, dopamine, which is abundant in the gut mucosa under homoeostasis, undergoes a sharp reduction upon intestinal inflammation. Here we analysed the role of the high-affinity dopamine receptor D3 (DRD3) in gut inflammation. Our results show that Drd3 deficiency confers a stronger immunosuppressive potency to Treg, attenuating inflammatory colitis manifestation in mice. Mechanistic analyses indicated that DRD3-signalling attenuates IL-10 production and limits the acquisition of gut-tropism. Accordingly, the ex vivo transduction of wild-type Treg with a siRNA for Drd3 induced a potent therapeutic effect abolishing gut inflammation. Thus, our findings show DRD3-signalling as a major regulator of Treg upon gut inflammation.
Repeated dermal application of the common preservative methylisothiazolinone triggers local inflammation, T cell influx, and prolonged mast cell-dependent tactile sensitivity in mice
PLOS ONE
Authors: Kline, Jaclyn M.; Arriaga-Gomez, Erica; Yangdon, Tenzin; Boo, Beebie; Landry, Jasmine; Saldias-Montivero, Marietta; Neamonitaki, Nefeli; Mengistu, Hanna; Silverio, Sayira; Zacheis, Hayley; Pasha, Dogukan; Martinov, Tijana; Fife, Brian T.; Chatterjea, Devavani
Abstract
Occupational exposure to toxic chemicals increases the risk of developing localized provoked vulvodynia-a prevalent, yet poorly understood, chronic condition characterized by sensitivity to touch and pressure, and accumulation of mast cells in painful tissues. Here, we topically sensitized female ND4 Swiss mice to the common household and industrial preservative methylisothiazolinone (MI) and subsequently challenged them daily with MI or acetone and olive oil vehicle on the labiar skin. MI-challenged mice developed significant, persistent tactile sensitivity and long-lasting local accumulation of mast cells alongside early, transient increases in CD4(+) and CD8(+) T cells, eosinophils, neutrophils, and increases in pro-inflammatory cytokines. Therapeutic administration of imatinib, a c-Kit inhibitor known to inhibit mast cell survival, led to reduced mast cell accumulation and alleviated tactile genital pain. We provide the first pre-clinical evidence of dermal MI-induced mast-cell dependent pain and lay the groundwork for detailed understanding of these intersections between MI-driven immunomodulation and chronic pain.