MicroRNAs (miRNA/miR) play an important role in gene regulatory networks through targeting mRNAs. They are involved in diverse biological processes such as cell proliferation, differentiation, angiogenesis, and apoptosis. Due to their pivotal effects on multiple genes and pathways, dysregulated miRNAs have been reported to be associated with different diseases, including colorectal cancer (CRC). Recent evidence indicates that aberrant miRNA expression is tightly linked with the initiation and progression of CRC. To elucidate the influence of miRNA regulation in CRC, it is critical to identify dysregulated miRNAs, their target mRNA genes and their involvement in gene regulatory and signaling networks. Various experimental and computational studies have been conducted to decipher the function of miRNAs involved in CRC. Experimental studies that are used for this purpose can be classified into two categories: direct/individual and indirect/high-throughput gene expression studies. Here we review miRNA target identification studies related to CRC with an emphasis on experimental data based on Luciferase reporter assays. Recent advances in determining the function of miRNAs and the signaling pathways they are involved in have also been summarized. The review helps bioinformaticians and biologists to find extensive information about downstream targets of dysregulated miRNAs, and their pro-/anti-CRC effects.

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The most prominent feature of systemic sclerosis (SSc) and other diseases associated with fibrosis is the prolonged activation of fibroblasts not eliminated by apoptosis, hence characterized by accumulation of more extra cellular matrix (ECM). We tend to verify if microRNA-29a (miR-29a) as an anti-fibrotic factor could induce apoptosis in SSc fibroblasts. We did not detect apoptosis in SSc fibroblasts. We found that Bcl-2 expression was upregulated in SSc fibroblasts and the ratio of Bax:Bcl-2 in these cells was significantly lower (p = 0.02) compared to normal fibroblasts. Transfection of both SSc and transforming growth factor-β (TGF-β) stimulated fibroblasts by miR-29a mimic, significantly decreased the expression of two anti-apoptotic members of the Bcl-2 family, Bcl-2 (p = 0.0005, p = 0.01) and Bcl-XL (p = 0.0001, p = 0.006), resulted in enhanced Bax:Bcl-2 ratio and induced a high rate of apoptosis. Recently, miR-29 has been introduced as an anti-fibrotic factor with potential therapeutic effect on SSc. Until now, it has not been proposed whether there is a relationship between miR-29a and apoptosis in SSc. According to our results, it seems that miR-29a is a potent inducer of apoptosis in SSc fibroblasts and an attenuator of ECM production in these cells. MiR-29a disrupted the expression profiling of Bcl-2 family proteins (Bax, Bcl-2 and Bcl-XL) which is the central point of dynamic life-death rheostat in many apoptotic pathways. Furthermore, dermal fibroblasts from patients with SSc showed elevation in TNF-α mRNA levels, while restoration of miR-29a decreases TNF-α production in these cells. Although further molecular studies are necessary to investigate the underlying apoptotic pathways, the present findings suggest that anti-fibrotic and pro-apoptotic properties of miR-29a could provide novel benefits toward the development of fibroblast-specific anti-fibrotic therapies.

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Ankylosing spondylitis (AS) is a chronic inflammatory disease of unknown origin, while both genetic and environmental factors have been demonstrated to be etiologically involved. Recent genome-wide association and replication studies have suggested that anthrax toxin receptor 2 (ANTXR2), interleukin-1 receptor 2 (IL1R2), caspase recruitment domain-containing protein 9 (CARD9), and small nuclear RNA-activating complex polypeptide 4 (SNAPC4) seem to be associated with AS pathogenesis. This case-control study was performed on 349 unrelated AS patients and 469 age- and gender-matched healthy controls, to investigate whether these non-MHC genes (IL1R2 rs2310173, ANTXR2 rs4333130, CARD9 rs4077515, and SNAPC4 rs3812571) influence the AS risk in Iranian population. ANTXR2 rs4333130 allele C (p = 0.0328; OR 0.744, 95% CI 0.598-0.927) and genotype CC (p = 0.0108; OR 0.273, 95% CI 0.123-0.605) were found to be significantly protective against AS. No other associations were found between AS and studied genes. The association between ANTXR2 rs4333130 and AS was independent of HLA-B27 status. Moreover, we found clinical disease severity scores (BASDAI and BASFI) and pain score were higher in ANTXR2 rs4333130 CT genotype. However, we observed that CARD9 allele C (p = 0.012) and genotype CC (p = 0.012) were significant protective factors against AS only in HLA-B27-negative patients, and IL1R2 rs2310173 genotype GT was mildly protective against AS only in HLA-B27-negative status. These findings support the role of non-MHC pathogenic pathways in susceptibility to AS and warrants more comprehensive studies focusing on these non-MHC pathways for developing novel therapeutic strategies.