miR-200c regulates IL8 expression by targeting IKBKB: a potential mediator of inflammation in leiomyoma pathogenesis

Mechanisms underlying aberrant expression of miR-29c in uterine leiomyoma

OBJECTIVE

To determine the expression of miR-29c and its target genes in leiomyoma and the role of NF-κB, specific protein 1 (SP1), and DNA methylation in its regulation.

DESIGN

Experimental study.

SETTING

Academic research laboratory.

PATIENT(S)

Women undergoing hysterectomy for leiomyoma.

INTERVENTION(S)

Over- and underexpression of miR-29c; blockade of transcription factors.

MAIN OUTCOME MEASURE(S)

MiR-29c and its target gene levels in leiomyoma and the effects of blockade of transcription factors on miR-29c expression.

RESULT(S)

Leiomyoma as compared with myometrium expressed significantly lower levels of miR-29c, with an inverse relationship with expression of its targets, COL3A1 and DNMT3A. Gain of function of miR-29c inhibited the expression of COL3A1 and DNMT3A at protein and mRNA levels, secreted COL3A1, and rate of cell proliferation. Loss of function of miR-29c had the opposite effect. E2, P, and their combination inhibited miR-29c in leiomyoma smooth muscle cells (LSMC). Phosphorylated NF-κB (p65) and SP1 protein expression were significantly increased in leiomyoma. SiRNA knockdown of SP1 and DNMT3A or their specific inhibitors significantly increased the expression of miR-29c, accompanied by the inhibition of cellular and secreted COL3A1 in siRNA-treated cells. Knockdown of p65 also induced miR-29c expression but had no effect on COL3A1 expression.

CONCLUSION(S)

MiR-29c expression is suppressed in leiomyoma, resulting in an increase in expression of its targets COL3A1 and DNMT3A. The suppression of miR-29c in LSMC is primarily mediated by SP1, NF-κB signaling, and epigenetic modification. Collectively, these results indicate a significant role for miR-29c in leiomyoma pathogenesis.

Identification and functional analysis of microRNA in myometrium tissue from spontaneous preterm labor

Spontaneous preterm labor is an important complication in perinatology characterized by early onset myometrium contractions leading to labor at preterm. However, the exact mechanism that maintain uterine quiescence and promote increased uterine contractility during labor were incompletely defined. MicroRNAs is a class of short non-coding RNAs that regulate gene expression at the post-transcriptional level by binding the 3' untranslated region of target mRNAs and play an important role in biological process and cellular functions. We hypothesized we could find differentially expressed microRNAs in the myometrium of women in spontaneous preterm labor. Thus, a microarray analysis of miRNAs of preterm myometrium was performed. 18 out of the 2006 detected microRNAs were found to be significantly dysregulated in myometrium in labor verse not in labor at preterm. Biological validation by quantitative real-time polymerase chain reaction confirms us a consistence rate of 83.3% (5 out of 6) with microarray analysis. The target genes for validated microRNAs were predicted by three algorithms (PicTar, TargetScan, and miRanda). Most of the potential targets of the miRNAs were relevant to positive regulation of cardiac muscle hypertrophy, reduction of cytosolic calcium ion concentration and relaxation of cardiac muscle as well as prostate cancer, adherents junction, regulation of actin cytoskeleton and regulation and other factor-regulated calcium reabsorption. Our result illustrates a characteristic microRNA profile in myometrium tissues and provides a new understanding of the process involved in spontaneous preterm labor.

miR-29c induction contributes to downregulation of vascular extracellular matrix proteins by glucocorticoids

Maternal undernutrition increases maternal glucocorticoids (GCs) and alters microRNA expression in offspring. Given that the mechanisms of GC action on vascular development are not clear, this study examined the influence of GCs on microRNA 29c (miR-29c) and its predicted targets in primary rat aorta smooth muscle cells (RAOSMCs). Dexamethasone (Dex) and corticosterone (Cor) time-dependently increased miR-29c expression and reduced collagen type III (Col3A1), collagen type IV (Col4A5), elastin (ELN), and matrix metalloproteinase-2 (MMP2) protein in RAOSMCs. These effects were blocked by mifepristone. These genes were also targeted by miR-29c, as confirmed by a significant decrease in luciferase reporter activity of Col3A1 (34%), Col4A5 (45%), ELN (17%), and MMP2 (28%). In cells transfected with reporter plasmids, including the 3'-untranslated region of genes targeted by miR-29c, treatment with Dex or Cor also resulted in decreases in luciferase activity. Gain or loss of function of miR-29c significantly altered mRNA expression of Col3A1 (26% and 26%, respectively), Col4A5 (28% and 32%, respectively), and MMP2 (24% and 14%, respectively) but did not affect ELN. Gain or loss of function of miR-29c also significantly altered protein levels of Col3A1 (51% and 16%, respectively), Col4A5 (56% and 22%, respectively), ELN (53% and 71%, respectively), and MMP2 (28% and 53%, respectively). Coincubation of anti-miR-29c with Dex or Cor partially attenuated the effects of these steroids on protein expression of Col3A1 (25% and 24%, respectively), Col4A5 (26% and 44%, respectively), ELN (31% and 55%, respectively), and MMP2 (46% and 26%, respectively) in RAOSMCs compared with anti-miR negative controls. Our results demonstrate that GCs regulate the expression of Col3A1, Col4A5, ELN, and MMP2, at least in part, through induction of miR-29c.

Effects of miRNA-197 overexpression on proliferation, apoptosis and migration in levonorgestrel treated uterine leiomyoma cells

BACKGROUND/AIMS

Uterine leiomyoma is the ahead benign tumor of the female genital tract, which resulted in menstrual abnormalities, recurrent pregnancy loss, and other serious gynecological disorders in women. Recently, as the process of exploring the brief molecular mechanisms of tumorgenesis, microRNAs (miRNAs) have attracted much more attention.

METHODS

In this study, we first confirmed that microRNA-197 (miR-197) was down-regulated significantly in human uterus leiomyoma by quantity real-time polymerase chain reaction, compared to normal uterus myometrium. Then we observed the potential effects of miR-197 overexpression on human uterus leiomyoma cells by cell counting kit 8, wound healing assay, and flow cytometric assessment separately.

RESULTS

The data showed that miR-197 could inhibit cell proliferation, induce cell apoptosis, and block cell migration in vitro. Coincidently, levonorgestrel (LNG), a well-known uterus leiomyoma therapy, could induce miR-197 expression in human uterus leiomyoma cells, and over-expression of miR-197 showed a synergy effect on human uterus leiomyoma cell proliferation and apoptosis with LNG.

CONCLUSION

In this study, the data showed that miR-197 could play an anti-oncogenic role in human uterus leiomyoma cells, and cooperate with LNG on the cell proliferation and apoptosis, which suggested that miR-197 might be a potential target and provided database for clinical treatment.

Integrated miRNA and mRNA expression profiling in inflamed colon of patients with ulcerative colitis

Background

Ulcerative colitis (UC) is associated with differential colonic expression of genes involved in immune response (e.g. IL8) and barrier integrity (e.g. cadherins). MicroRNAs (miRNAs) are regulators of gene expression and are involved in various immune-related diseases. In this study, we investigated (1) if miRNA expression in UC mucosa is altered and (2) if any of these changes correlate with mucosal mRNA expression. Integration of mRNA and miRNA expression profiling may allow the identification of functional links between dysregulated miRNAs and their target mRNA.

Methodology

Colonic mucosal biopsies were obtained from 17 UC (10 active and 7 inactive) patients and 10 normal controls. Total RNA was used to analyze miRNA and mRNA expression via Affymetrix miRNA 2.0 and Affymetrix Human Gene 1.0ST arrays, respectively. Both miRNA and gene expression profiles were integrated by correlation analysis to identify dysregulated miRNAs with their corresponding predicted target mRNA. Microarray data were validated with qRT-PCR. Regulation of IL8 and CDH11 expression by hsa-miR-200c-3p was determined by luciferase reporter assays.

Results

When comparing active UC patients vs. controls, 51 miRNAs and 1543 gene probe sets gave significantly different signals. In contrast, in inactive UC vs. controls, no significant miRNA expression differences were found while 155 gene probe sets had significantly different signals. We then identified potential target genes of the significantly dysregulated miRNAs and genes in active UC vs. controls and found a highly significant inverse correlation between hsa-miR-200c-3p and IL8, an inflammatory marker, and between hsa-miR-200c-3p and CDH11, a gene related to intestinal epithelial barrier function. We could demonstrate that hsa-miR-200c-3p directly regulates IL8 and CDH11 expression.

Conclusion

Differential expression of immune- and barrier-related genes in inflamed UC mucosa may be influenced by altered expression of miRNAs. Integrated analysis of miRNA and mRNA expression profiles revealed hsa-miR-200c-3p for use of miRNA mimics as therapeutics.

The regulatory function of miR-200c on inflammatory and cell-cycle associated genes in SK-LMS-1, a leiomyosarcoma cell line

Uterine leiomyosarcoma is a relatively rare malignancy with high mortality due to metastasis and chemoresistance. Leiomyosarcomas share similar morphological characteristics with leiomyomas which are considered to have the potential of transformation into leiomyosarcoma. Accumulated evidence suggests that microRNAs acting as regulators of gene expression at the posttranscriptional level play key roles in diverse biological processes including cellular transformation and tumorigenesis. We hypothesized that miR-200c, whose expression is altered in leiomyomas, equally plays a key role in pathogenesis of leiomyosarcoma. Using SK-LMS-1 leiomyosarcoma cell line as an in vitro model here, we found that the level of expression of miR-200c was significantly lower as compared to isolated leiomyoma smooth muscle cells. Overexpression (gain-of-function) of miR-200c in SK-LMS-1 through direct interaction with 3'-untranslated region of IKBKB, IL8, CDK2, and CCNE2, respectively, resulted in suppression of their expression as determined by quantitative polymerase chain reaction and Western blot analysis. Additionally, gain-of-function of miR-200c through inhibition of IKBKB expression resulted in decreased p65 transcriptional activity in IL8 promoter. Gain-of-function of miR-200c also increased SK-LMS-1 caspase 3/7 activity and inhibited their proliferation and migration. In summary, the results suggest that a progressive decline in miR-200c expression which alters transcriptional regulation of specific target genes that control nuclear factor-κB signaling pathway, inflammation, cell cycle, and migration, in part may promote development and progression of leiomyosarcomas, including their transformation from leiomyomas.