Tight junctions and their regulation by non-coding RNAs

Abstract

Tight junction (TJ) is a “zippering up” junction structure located at the uppermost portion of adjacent epithelial/endothelial cells in organs and tissues. TJs maintain the relative stability of intracellular substances and functions by closing or opening intercellular pathways, coordinating the entry and exit of molecules of different sizes and charges, and regulating the permeability of paracellular barrier. TJs also prevent microbial invasion, maintain epithelial/endothelial cell polarity, and regulate cell proliferation. TJs are widely present in the skin and mucosal epithelial barriers, intestinal epithelial barrier, glomerular filtration barrier, bladder epithelial barrier, blood-brain barrier, brain-blood tumor barrier, and blood-testis barrier. TJ dysfunction in different organs can lead to a variety of diseases. In addition to signal pathways, transcription factors, DNA methylation, histone modification, TJ proteins can also be regulated by a variety of non-coding RNAs, such as micro-RNAs, long-noncoding RNAs, and circular RNAs, directly or indirectly. This review summarizes the structure of TJs and introduces the functions and regulatory mechanisms of TJs in different organs and tissues. The roles and mechanisms of non-coding RNAs in the regulation of TJs are also highlighted in this review.

Relationship Between Amyloid-β Deposition and Blood–Brain Barrier Dysfunction in Alzheimer’s Disease

“…Among these, BMECs express a wide range of transporters and receptors involved in the selective uptake of substances from the blood to the brain ( Georgieva et al, 2020 ). Tight junctions (TJs), which are highly specialized intercellular-adhesion complexes, exist in epithelial and endothelial cells ( Zhao et al, 2021 ). The TJs in BMECs act as selective barriers to regulate the movement of non-ionic molecules between the blood and brain through the paracellular pathway to maintain cerebral homeostasis ( Huang Z. et al, 2020 ).…”

Transcriptional Changes after Enniatins A, A1, B and B1 Ingestion in Rat Stomach, Liver, Kidney and Lower Intestine

“…As a consequence of the development of oxidative-stress-induced cellular damage and apoptosis, the onset of inflammation and structural disfunction can successively occur [ 47 ]. The activity of the structural protein occludin, for instance, is related to intestinal epithelial disorders and abnormal secretory function [ 48 ]. Its upregulation in intestinal cells was implicated in the decrease of gut permeability in accordance with this result, hinting the activation of defense mechanisms [ 49 ].…”

High SPIN4 Expression Is Linked to Advanced Nodal Status and Inferior Prognosis in Nasopharyngeal Carcinoma Patients

“…Using bioinformatics analysis, we further found that the tight junction proteins TJP1 and TJP2 show significant positive correlations with SPIN4 and are linked to cancer cell survival [ 22 ]. In addition, it has been reported that H3K4me3 can activate TJP1 transcription [ 26 ]. These suggest that SPIN4 may increase TJP1 transcripts through H3K4me3-mediated transcriptional activation.…”

“…Tight junction proteins, including TJP1, have been suggested to maintain the intercellular configuration of neural stem cells [ 34 ]. In addition to activating TJP1 transcription, [ 26 ], H3K4me3 has been suggested to play a critical role in the genetic regulation of pluripotency [ 35 ]. However, the correlations among the expression of SPIN4 and tight junction proteins, radioresistance, and stem cell maintenance deserve further investigation.…”