Table 1.

Clinical implications of miRNAs within the pathophysiology of the different subtypes of IBS

General functional implication	miRNA	miRNA regulation	Target	Specific biological role	Type of sample	Reference
Barrier functions, intestinal permeability and miRNAs	miR-16	Downregulated	CLDN2	Barrier function	Small bowel mucosa	[62]
	miR-125b-5p	Downregulated	CGN	Barrier function	Small bowel mucosa
	miR-29a	Upregulated	ZO-1 and CLDN1	Regulation of intestinal barrier function	Human intestinal mucosal epithelia	[65]
	miR-29a	Upregulated	GLUL	Regulation of intestinal permeability	Blood microvesicles, small bowel and colon tissues	[68]
	miR-29a	Upregulated	AQP1, AQP3, and AQP8	Regulation of intestinal permeability	Colonic epithelial cells from IBS rats	[71]
	miR-29a/b	Upregulated	NKRF and CLDN1	Regulation of intestinal permeability	Intestinal tissues	[70]
	miR-148b-5p	Upregulated	RGS2	Regulation of colonic epithelial permeability	Serum exosomes	[74]
	miR-219a-5p	Downregulated	–	Intestinal permeability and visceral nociception	Colonic mucosal biopsies	[72]
	miR-338-3p	Downregulated	–	Intestinal permeability and visceral nociception	Colonic mucosal biopsies
Visceral conditions and miRNAs	miR-29a	Upregulated	HTR7	Visceral hyperalgesia	Intestinal biopsies	[79]
	miR-199	Upregulated (due to acupuncture)	TRPV1	Visceral hypersensitivity	Colonic tissue	[82]
	miR-199a/b	Downregulated	TRPV1	Visceral pain	Biopsies from the ascending, transverse, and descending colon	[76]
	miR-200a	Upregulated	CNR1 and SERT	Visceral hyperalgesia	Distal colon tissues from IBS-D rats	[77]
	miR-495	Downregulated	PKIB	Visceral sensitivity	Mouse rectal tissue	[81]
Inflammatory conditions and miRNAs	miR-150	Upregulated	AKT2	Inflammatory bowel condition and discomfort	Blood	[53, 83]
	miR-342-3p	Upregulated	CACNA1C	Colonic motility, pain signaling, and smooth muscle function	Blood
	miR-181c-5p	Downregulated	IL1A	Low-grade inflammation	Colon tissues of IBS rats	[85]
	miR-510	Downregulated	PRDX1	LPS-induced inflammatory damage	Post-infectious IBS colonic mucosal tissues	[84]
Cellular remodeling of gastrointestinal cells and miRNAs	miR-199a-3p	Downregulated	SRF	Regulation of gastrointestinal SMC phenotype	SMCs	[88]
	miR-214	Downregulated	SRF
	miR-145	Downregulated	MYOCD
	miR-143	Downregulated	ELK1
	miR-145	Downregulated	ELK1
	miR-214	Downregulated	ELK1
	miR-143	Downregulated	SRF	SMC differentiation and proliferation	SMCs	[89]
	miR-145	Downregulated	SRF
	miR-375	Upregulated	Pdk1	Enteric neuron survival and gastrointestinal motility	Enteric neurons	[90]
Other biological implications in IBS	miR-10b-5p	Downregulated	KLF11	Diabetes and intestinal dysmotility	Interstitial cells of Cajal	[102]
	miR-24	Upregulated	SERT	Pain and inflammation	Intestinal mucosa epithelial cells of IBS patients and mice	[99]
	miR-26a	Upregulated	–	Involved in the MAKP signaling pathway	Plasma	[93]
	miR-29b	Upregulated	–	Involved in the MAKP signaling pathway	Plasma
	miR-106b	Upregulated	–	Involved in the MAKP signaling pathway	Plasma
	miR-145	Downregulated in IBS-C	–	Estrogen-dependent local intestinal modulation of immune response	Colon mucosa	[94]
	miR-148-5p	Upregulated in IBS-D	–		Colon mucosa
	miR-592	Downregulated in IBS-D	–		Colon mucosa
	miR-16	Downregulated	HTR4	IBS-D symptoms	Jejunal mucosal biopsies	[100]
	miR-103	Downregulated	HTR4	IBS-D symptoms	Jejunal mucosal biopsies
	miR-199b	Downregulated	–	Increased number of coliforms	Serum	[97]
	miR-490-5p	Downregulated	–	Regulation of mast cell proliferation and apoptosis	p815 mast cells	[101]
	miR-510	Downregulated	HTR3E	Increased IBS-D risk	Colonic mucosal tissue	[92]
	miR-135a-5p	Upregulated	–	IBS-D symptoms	Serum	[104]
	miR-148a-3p	Upregulated	–	IBS-D symptoms	Serum
	miR-149-5p	Upregulated	–	IBS-D symptoms	Serum
	miR-190a-5p	Upregulated	–	IBS-D symptoms	Serum
	miR-575	Upregulated	–	IBS-D symptoms	Serum
	miR-1305	Upregulated	–	IBS-D symptoms	Serum
	miR-194-5p	Downregulated	–	IBS-D symptoms	Serum
	miR-127-5p	Downregulated	–	IBS-D symptoms	Serum
Biomarkers	miR-23a	Upregulated	–	–	Serum	[106]
	miR-181b	Upregulated	–	–	Serum