MicroRNA-10b promotes nucleus pulposus cell proliferation through RhoC-Akt pathway by targeting HOXD10 in intervetebral disc degeneration

MicroRNA-146a reduces IL-1 dependent inflammatory responses in the intervertebral disc

Because miR-146a expression in articular chondrocytes is associated with osteoarthritis (OA), we assessed whether miR-146a is linked to cartilage degeneration in the spine. Monolayer cultures of nucleus pulposus (NP) cells from the intervertebral discs (IVD) of bovine tails were transfected with a miR-146a mimic. To provoke inflammatory responses and catabolic extracellular matrix (ECM) degradation, cells were co-treated with interleukin-1 (IL-1). Transfection of miR-146a decreases IL-1 induced mRNA levels of inflammatory genes and catabolic proteases in NP cells based on quantitative real-time reverse transcriptase PCR (qRT-PCR) analysis. Similarly, miR146a suppresses IL-1 induced protein levels of matrix metalloproteinases and aggrecanases as revealed by immunoblotting. Disc segments from wild type (WT) and miR-146a knockout (KO) mice were cultured ex vivo in the presence or absence of IL-1 for 3days. Histological and immuno-histochemical (IHC) analyses of disc organ cultures revealed that IL-1 mediates changes in proteoglycan (PG) content and in-situ levels of catabolic proteins (MMP-13 and ADAMTS-5) in the nucleus pulposus of the disc. However, these IL-1 effects are more pronounced in miR-146a KO discs compared to WT discs. For example, absence of miR-146a increases the percentage of MMP-13 and ADAMTS-5 positive cells after treatment with IL-1. Thus, miR-146a appears to protect against IL-1 induced IVD degeneration and inflammation. Stimulation of endogenous miR-146a expression or exogenous delivery of miRNA-146a are viable therapeutic strategies that may decelerate disc degeneration and regain a normal homeostatic balance in extracellular matrix production and turn-over.

MicroRNA-410 suppresses migration and invasion by targeting MDM2 in gastric cancer

Gastric cancer is one of the most frequent malignancies in tumors in the East Asian countries. Identifying precise prognostic markers and effective therapeutic targets is important in the treatment of gastric cancer. microRNAs (miRNAs) play important roles in tumorigenesis. However, the mechanisms by which miRNAs regulate gastric cancer metastasis remain poorly understood. In this study, we found that the levels of miR-410 in gastric cancer and cell lines were much lower than that in the normal control, respectively, and the lower level of miR-410 was significantly associated with lymph-node metastasis. Transfection of miR-410 mimics could significantly inhibit the cell proliferation, migration and invasion in the HGC-27 gastric cancer cell lines. In contrast, knockdown of miR-410 had the opposite effect on the cell proliferation, migration and invasion. Moreover, we also found that MDM2 was negatively regulated by miR-410 at the post-transcriptional level, via a specific target site with the 3′UTR by luciferase reporter assay. The expression of MDM2 was inversely correlated with miR-410 expression in gastric cancer tissues, and overexpression of MDM2 in miR-410-transfected gastric cancer cells effectively rescued the inhibition of cell proliferation and invasion caused by miR-410. Thus, our findings suggested that miR-410 acted as a new tumor suppressor by targeting the MDM2 gene and inhibiting gastric cancer cells proliferation, migration and invasion. The findings of this study contributed to the current understanding of these functions of miR-410 in gastric cancer.

Identification of differentially expressed miRNAs between white and black hair follicles by RNA-sequencing in the goat (Capra hircus)

MicroRNAs (miRNAs) play a key role in many biological processes by regulating gene expression at the post-transcriptional level. A number of miRNAs have been identified from livestock species. However, compared with other animals, such as pigs and cows, the number of miRNAs identified in goats is quite low, particularly in hair follicles. In this study, to investigate the functional roles of miRNAs in goat hair follicles of goats with different coat colors, we sequenced miRNAs from two hair follicles samples (white and black) using Solexa sequencing. A total of 35,604,016 reads were obtained, which included 30,878,637 clean reads (86.73%). MiRDeep2 software identified 214 miRNAs. Among them, 205 were conserved among species and nine were novel miRNAs. Furthermore, DESeq software identified six differentially expressed miRNAs. Quantitative PCR confirmed differential expression of two miRNAs, miR-10b and miR-211. KEGG pathways were analyzed using the DAVID website for the predicted target genes of the differentially expressed miRNAs. Several signaling pathways including Notch and MAPK pathways may affect the process of coat color formation. Our study showed that the identified miRNAs might play an essential role in black and white follicle formation in goats.

MicroRNA-424 is down-regulated in hepatocellular carcinoma and suppresses cell migration and invasion through c-Myb

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related mortality worldwide. MicroRNAs (miRNAs) are important regulators of multiple cellular processes, and the aberrant miRNAs expressions have been observed in different types of cancer including HCC. Their pathysiologic role and their relevance to tumorigenesis are still largely unknown. In this study, we demonstrated the down-regulation of miR-424 in HCC cell lines and tissues by quantitative RT-PCR analyses. Overexpression of miR-424 reduced the HCC cell prolifetation, migration, and invasion. Conversely, inhibiton of miR-424 expression significantly accelerated the cell proliferation, migration, and invasion. In addition, we further identified c-Myb as a functional downstream target of miR-424 by directly targeting the 3'UTR of c-Myb. Furthermore, overexpression of c-Myb impaired miR-424-induced inhibition of proliferation and invasion in HCC cells. Our results demonstrated that miR-424 was involved in tumorigenesis of HCC at least in part by suppression of c-Myb.

Clarifying the nomenclature of intervertebral disc degeneration and displacement: from bench to bedside

As a significant determinant of low back pain, intervertebral disc degeneration (IDD) has attracted more and more attention of both investigators and physicians. Disc herniation, termed as intervertebral disc displacement, is amongst the most prevalent spinal diseases closely linked with IDD. Due to the same origins and similar pathophysiology, the ambiguity regarding the similarity and difference of IDD and intervertebral disc displacement thus remains. The aim of this study was to clarify the nomenclature of IDD and disc herniation in terms of molecular etiology, pathophysiology, nature history and clinical outcomes. Collectively, IDD is a type of multifaceted, progressive spinal disease with or without clinical symptoms as back pain, characterized by extracellular matrix and the integrity of NP and AF lost, fissures formation. Disc herniation (termed as intervertebral disc displacement) is a type of spinal disease based on IDD or not, with local pain and/or sciatica due to mechanical compression and autoimmune cascades upon the corresponding nerve roots. Clarifying the nomenclature of intervertebral disc degeneration and displacement has important implications both for investigators and for physicians.

miR-21 promotes human nucleus pulposus cell proliferation through PTEN/AKT signaling

The precise role of nucleus pulposus cell proliferation in the pathogenesis of intervertebral disc degeneration remains to be elucidated. Recent findings have revealed that microRNAs, a class of small noncoding RNAs, may regulate cell proliferation in many pathological conditions. Here, we showed that miR-21 was significantly upregulated in degenerative nucleus pulposus tissues when compared with nucleus pulposus tissues that were isolated from patients with idiopathic scoliosis and that miR-10b levels were associated with disc degeneration grade. Moreover, bioinformatics target prediction identified PTEN as a putative target of miR-21. miR-21 inhibited PTEN expression by directly targeting the 3′UTR, and this inhibition was abolished through miR-21 binding site mutations. miR-21 overexpression stimulated cell proliferation and AKT signaling pathway activation, which led to cyclin D1 translation. Additionally, the increase in proliferation and cyclin D1 expression induced by miR-21 overexpression was almost completely blocked by Ly294002, an AKT inhibitor. Taken together, aberrant miR-21 upregulation in intervertebral disc degeneration could target PTEN, which would contribute to abnormal nucleus pulposus cell proliferation through derepressing the Akt pathway. Our study also underscores the potential of miR-21 and the PTEN/Akt pathway as novel therapeutic targets in intervertebral disc degeneration.