Functional relevance of T helper 17 (Th17) cells and the IL-17 cytokine family in inflammatory bowel disease

Abstract

The recent discovery and characterization of T helper 17 cells (Th17) and their signature cytokines (IL-17) represents a hallmark in T-cell immunobiology by providing a new distinctive pathway for the communication between adaptive and innate immunity. From the six members of the IL-17 cytokine family presently known, at least two have evident proinflammatory qualities and are involved in several chronic inflammatory disorders, including inflammatory bowel disease (IBD). IL-17A and IL-17F are abundantly found in inflamed IBD mucosa, suggesting their pivotal role in IBD. However, the precise implication of IL-17 cytokine family members in IBD pathogenesis and the mechanisms regulating their secretion are incompletely understood. Importantly, recent findings suggest that beyond IL-17 production-Th17 cells may secret a plethora of other effector cytokines such as IL-21, IL-22, and IL-9- which is in part induced by its own IL-9 production. However, the use of anti-IL-17 therapeutic strategies in experimental models of chronic inflammation results in disease-ameliorating effects suggesting their potential use in IBD patients. In this review article we discuss the latest findings on the role of Th17 cells and IL-17 family members in IBD immunopathology, as well as research perspectives.

Perilla frutescens extract ameliorates DSS-induced colitis by suppressing proinflammatory cytokines and inducing anti-inflammatory cytokines

“…PE suppressed TNF-␣ mRNA expression in distal colon, and the ingredients inhibited the production of proinflammatory cytokines, such as TNF-␣, IL-1␤, and IL-6, in vitro. In addition to these proinflammatory cytokines, IL-17A, which is secreted by Th17 cells, is also a crucial cytokine in IBD (9,12,14,45). In this study, PE significantly decreased secretion of serum IL-17A and expression of colonic IL-17A mRNA.…”

Gene expression alterations in inflamed and unaffected colon mucosa from patients with mild inflammatory bowel disease

“…Alterations in the expression levels of inflammatory cytokines in the colon mucosa is a key pathological characteristic of IBD, and it has been associated with disease activity and mucosal inflammation (20)(21)(22). The present study investigated the mRNA expression levels of IFN-γ and IL-17 in inflamed and unaffected colon biopsies from patients with UC using RT-qPCR.…”

Interleukin 17 gene and protein expression are increased in patients with ulcerative colitis

“…2,3 The recent discovery and characterization of Th17 and their signature cytokines (IL-17) represents a hallmark in T-cell immunobiology by providing a new, distinctive pathway for communication between adaptive and innate immunity. 4 This is the first study to our best knowledge with a larger sample that explores IL-17 gene and protein expression from colonic biopsies in patients with ulcerative colitis (UC) and includes a healthy control group.…”