Table 1.

Functional studies on micro RNAs (miRNAs)

First author	Study model	miRNA of interest	mRNA/pathway target	Findings
Nguyen144	AIEC infection in T84 cells and mouse enterocytes. Translational studies in ileal CD biopsies	miR-30C and miR-130A	ATG5 ATG16L1	Adherent  Escherichia coli upregulate miRNAs, reduce levels of ATG5 and ATG16L1 and inhibit autophagy
Zhai145	Jurkat T cells Colonic epithelial cells	miR-142-3p	ATG16L1	Reduced ATG16L1 mRNA and protein levels, regulating autophagy in CD.
Lu146	HCT116, SW480, HeLa and U2OS cell lines. Colonic biopsies from CD and healthy controls	miR106B, miR93	ATG16L1	Reduced levels of ATG16L1 and autophagy
Brest10	HEK-293 cells Colonic biopsies	miR-196	IRGM	A risk variant of IRGM alters the binding site for miR-196 and causes deregulation of IRGM-dependent xenophagy in CD
Brain9	Dendritic cell line, miR-29 KO murine models	miR-29	IL-12p40 (direct target) IL-12p19 (indirect target)	NOD2 induces miR-29 release and limits IL- 23 release NOD2 polymorphism alters the expression of miR-29 and contributes to pathogenesis in CD.
Xue147	IL-10 KO mice MyD88 KO mice RAG KO mice Murine dendrite cells	miR-10a	IL-12/IL-23p40	miR-10a expression is regulated by the intestinal microbiota and targets the Th17 pathway. This miRNA may play a role in intestinal homoeostasis
Koukos148	HCT-116 colonocyte cells, murine models and colonic biopsies from  patients with UC	miR-124	STAT3	Downregulation of miR-124 results in proinflammatory response in UC
Shi5 Yang149	miR-21 KO DSS model and wild type mouse models Caco-2 cells, colonic biopsies from UC and healthy controls	mir-21	RhoB	miR-21 is overexpressed in inflammation and tissue injury. miR-21 KO improves survival in DSS colitis mouse model Targeting RhoB impairs the tight junction integrity and decreases transepithelial resistance and increases inulin permeability
Nata150	IL-10 deficient mice	miR-146b	siah2	miR-146b improves intestinal inflammation and epithelial barrier by activating NFκB
Chuang92	HCT116 colonic epithelial cells	miR-192, miR-495, miR-512, miR-671	NOD2	Downregulates NOD2 expression, suppresses NFκB, inhibits IL8 and CXCL3 expression
Chen151	Intestinal epithelial cells Intestinal biopsies	miR-200b	TGFβ	miR-200b promotes the growth of intestinal epithelial cells by inhibiting epithelial-mesenchymal transition via TGFβ
Feng152	UC intestinal biopsies HCT116 cells HT29 cells	miR-126	IκBα	Promotes NFκB mediated inflammation by targeting IκBα, a known inhibitor of the NFκB pathway.
Nguyen153	Caco2-BBE cells Mouse epithelial cells Colonic CD tissues	miR-7	CD98 expression	miR-7 regulates the expression of CD98. CD98 expression upregulated and miR-7 decreased in actively inflamed CD tissues.
Singh123	miR-155 KO mice	miR-155	Th17 pathway	miR-155 KO mice models and demonstrated that these mice are protected from experimental colitis compared with wild type mice.
Wu8	miR-21 KO TNBS and T cell transfer model of colitis miR-21 KO DSS colitis model	miR-21	Th1 pathway	miR-21 KO results in reduced DSS induced colitis but exacerbated inflammation in TNBS and T cell transfer model of colitis

AIEC, adherent invasive Escherichia coli; CD, Crohn's disease; DSS, dextran sulfate sodium; IL, interleukin; IRGM, immunity related GTPase family M protein; KO, knockout; miR, microRNA; NFκB, nuclear factor-κB; NOD2, nuclear oligomerisation domain-containing protein 2; TGFβ, transforming growth factor β; TNBS, trinitrobenzene sulfonic acid.