MicroRNA-127-5p regulates matrix metalloproteinase 13 expression and interleukin-1β-induced catabolic effects in human chondrocytes

A bioinformatic analysis of microRNAs role in osteoarthritis

OBJECTIVE

To evaluate the underlying function of microRNAs (miRNAs) in osteoarthritis (OA).

DESIGN

A bioinformatic analysis of miRNAs-OA studies was completed in multiple databases. All identified articles were assessed using specific inclusion and exclusion criteria (Eligible case-control studies for the present study included those which investigated miRNAs differential expression in cartilage tissues and cells of OA and controls. Abstracts, case reports, conference presentations, editorials, and expert opinions were excluded.). We performed bioinformatic analysis and assessed which miRNAs are commonly elevated or decreased in cartilage of OA, and assessed putative targets of these miRNAs using TargetScan, Database for Annotation, Visualization and Integrated Discovery (DAVID), FunRich and String.

RESULTS

Fifty seven studies were included in this study. Our current review has identified 46 differentially expressed miRNAs involved in autophagy, inflammation, chondrocyte apoptosis, chondrocyte differentiation & homeostasis, chondrocyte metabolism and degradation of the extracellular matrix (ECM). Additionally, our literature search identified a wide range of miRNAs that have been shown to be differentially expressed in OA. The function of up-regulated miRNAs primarily target nucleus, whereas the function of down-regulated miRNAs primarily target transcription.

CONCLUSIONS

Comprehensive analysis of all miRNAs studies reveals cooperation in miRNA signatures and suggests that there may be two biologically synergic classes of miRNAs that are associated with OA. This finding suggests that miRNAs may be useful as diagnostic biomarkers and/or may provide new therapeutic targets in OA. Furthermore, a better understanding of the targets of these miRNAs will accelerate biomedical discoveries and improve clinical care based on new knowledge of OA-related disease mechanisms.

miR-127-5p promotes chondrogenic differentiation in rat bone marrow mesenchymal stem cells

The effect and related mechanisms of miR-127-5p on the cartilage differentiation of rat bone marrow mesenchymal stem cells (BMSCs) was investigated. Rat BMSCs were generated and transfected with miR-127-5p, RT-PCR and Safranin O staining were used to detect the effect of miR-127-5p on the cartilage differentiation of rat BMSCs. Western blot analysis was used to detect the related mechanisms of miR-127-5p on the cartilage differentiation of rat BMSCs. Genes related to cartilage differentiation such as Sox9, collagen II and aggrecan were significantly increased in the group which were transfected with miR-127-5p, while collagen X, which was related to cartilage hypertrophy, was decreased in the miR-127-5p transfected group. Safranin O staining revealed that the expression of chondroitin sulfate was significantly increased in the group of miR-127-5p, than the miRNA control group. Western blot analysis showed that miR-127-5p transfection promoted the expression of Sox9, while decreased the expression of Runx2 of rat BMSCs. In conclusion, via increasing the expression of Sox9 and decreasing the expression of Runx2, miR-127-5p could promote cartilage differentiation and decrease cartilage hypertrophy of rat BMSCs.

Sexual dimorphism in the fetal cardiac response to maternal nutrient restriction

Poor maternal nutrition causes intrauterine growth restriction (IUGR); however, its effects on fetal cardiac development are unclear. We have developed a baboon model of moderate maternal undernutrition, leading to IUGR. We hypothesized that the IUGR affects fetal cardiac structure and metabolism. Six control pregnant baboons ate ad-libitum (CTRL)) or 70% CTRL from 0.16 of gestation (G). Fetuses were euthanized at C-section at 0.9G under general anesthesia. Male but not female IUGR fetuses showed left ventricular fibrosis inversely correlated with birth weight. Expression of extracellular matrix protein TSP-1 was increased (p<0.05) in male IUGR. Expression of cardiac fibrotic markers TGFβ, SMAD3 and ALK-1 were downregulated in male IUGRs with no difference in females. Autophagy was present in male IUGR evidenced by upregulation of ATG7 expression and lipidation LC3B. Global miRNA expression profiling revealed 56 annotated and novel cardiac miRNAs exclusively dysregulated in female IUGR, and 38 cardiac miRNAs were exclusively dysregulated in males (p<0.05). Fifteen (CTRL) and 23 (IUGR) miRNAs, were differentially expressed between males and females (p<0.05) suggesting sexual dimorphism, which can be at least partially explained by differential expression of upstream transcription factors (e.g. HNF4α, and NFκB p50). Lipidomics analysis of fetal cardiac tissue exhibited a net increase in diacylglycerol and plasmalogens and a decrease in triglycerides and phosphatidylcholines. In summary, IUGR resulting from decreased maternal nutrition is associated with sex-dependent dysregulations in cardiac structure, miRNA expression, and lipid metabolism. If these changes persist postnatally, they may program offspring for higher later life cardiac risk.

Dysregulated miR-127-5p contributes to type II collagen degradation by targeting matrix metalloproteinase-13 in human intervertebral disc degeneration

BACKGROUND

Intervertebral disc degeneration (IDD) is a chronic disease associated with the degradation of extracellular matrix (ECM). Matrix metalloproteinase (MMP)-13 is a major enzyme that mediates the degradation of ECM components. MMP-13 has been predicted to be a potential target of miR-127-5p. However, the exact function of miR-127-5p in IDD is still unclear.

OBJECTIVE

We designed this study to evaluate the correlation between miR-127-5p level and the degeneration of human intervertebral discs and explore the potential mechanisms.

METHODS

miR-127-5p levels and MMP-13 mRNA levels were detected by quantitative real-time polymerase chain reaction (qPCR). To determine whether MMP-13 is a target of miR-127-5p, dual luciferase reporter assays were performed. miR-127-5p mimic and miR-127-5p inhibitor were used to overexpress or downregulate miR-127-5p expression in human NP cells, respectively. Small interfering RNA (siRNA) was used to knock down MMP-13 expression in human NP cells. Type II collagen expression in human NP cells was detected by qPCR, western blotting, and immunofluorescence staining.

RESULTS

We confirmed that miR-127-5p was significantly downregulated in nucleus pulposus (NP) tissue of degenerative discs and its expression was inversely correlated with MMP-13 mRNA levels. We reveal that MMP-13 may act as a target of miR-127-5p. Expression of miR-127-5p was inversely correlated with type II collagen expression in human NP cells. Moreover, suppression of MMP-13 expression by siRNA blocked downstream signaling and increased type II collagen expression.

CONCLUSION

Dysregulated miR-127-5p contributed to the degradation of type II collagen by targeting MMP-13 in human IDD. Our findings highlight that miR-127-5p may serve as a new therapeutic target in IDD.

Role of MicroRNA in Osteoarthritis

Although the potential effect of aberrant expression of catabolic and anabolic genes on the development of osteoarthritis (OA) is well-documented, the regulatory mechanism for the expression of these genes in articular chondrocytes remains to be elucidated. The recent advances in epigenetic studies have identified microRNA (miRNA) as one of the epigenetic mechanisms for the regulation of gene expression. This mini review highlights the role of miRNA in the regulation of gene expression in articular chondrocytes and its significance in the pathogenesis of OA, with a discussion on the potential of miRNA as a new biomarker and therapeutic target for OA. Further investigations are required to determine the specificity, sensitivity, and efficacy of miRNA for clinical applications.

Epigallocatechin-3-O-gallate modulates global microRNA expression in interleukin-1β-stimulated human osteoarthritis chondrocytes: potential role of EGCG on negative co-regulation of microRNA-140-3p and ADAMTS5

PURPOSE

MicroRNAs (miRNAs) are short, non-coding RNAs involved in almost all cellular processes. Epigallocatechin-3-O-gallate (EGCG) is a green tea polyphenol and is known to exert anti-arthritic effects by inhibiting genes associated with osteoarthritis (OA). This study was undertaken to investigate the global effect of EGCG on interleukin-1β (IL-1β)-induced expression of miRNAs in human chondrocytes.

METHODS

Human chondrocytes were derived from OA cartilage and then treated with EGCG and IL-1β. Human miRNA microarray technology was used to determine the expression profile of 1347 miRNAs. Microarray results were verified by taqman assays and transfection of chondrocytes with miRNA inhibitors.

RESULTS

Out of 1347 miRNAs, EGCG up-regulated expression of 19 miRNAs and down-regulated expression of 17 miRNAs, whereas expression of 1311 miRNAs remains unchanged in IL-1β-stimulated human OA chondrocytes. Bioinformatics approach showed that 3`UTR of ADAMTS5 mRNA contains the 'seed-matched-sequence' for hsa-miR-140-3p. IL-1β-induced expression of ADAMTS5 correlated with down-regulation of hsa-miR-140-3p. Importantly, EGCG inhibited IL-1β-induced ADAMTS5 expression and up-regulated the expression of hsa-miR-140-3p. This EGCG-induced co-regulation between ADAMTS5 and hsa-miR-140-3p becomes reversed in OA chondrocytes transfected with anti-miR-140-3p.

CONCLUSIONS

This study provides an important insight into the molecular basis of the reported anti-arthritic effects of EGCG. Our data indicate that the potential of EGCG in OA chondrocytes may be related to its ability to globally inhibit inflammatory response via modulation of miRNAs expressions.

Roles of microRNA and signaling pathway in osteoarthritis pathogenesis

Osteoarthritis (OA) is a common chronic degenerative joint disease, with complicated pathogenic factors and undefined pathogenesis. Various signaling pathways play important roles in OA pathogenesis, including genetic expression, matrix synthesis and degradation, cell proliferation, differentiation, apoptosis, and so on. MicroRNA (miRNA) is a class of non-coding RNA in Eukaryon, regulating genetic expression on the post-transcriptional level. A great number of miRNAs are involved in the development of OA, and are closely associated with different signaling pathways. This article reviews the roles of miRNAs and signaling pathways in OA, looking toward having a better understanding of its pathogenesis mechanisms and providing new therapeutic targets for its treatment.

Serum and knee synovial fluid matrixmetalloproteinase-13 and tumor necrosis factor-alpha levels in patients with late stage osteoarthritis

Objective

To compare the levels of MMP-13 and TNF-α in late stage osteoarthritis, define their predominant pathways and investigate their correlation with McMaster Universities Arthritis Index scores.

Patients and methods

A total of 42 patients (mean age 64 ± 8.8) with grade 3 and grade 4 knee osteoarthritis according to Kellegren- Lawrence criteria and who were scheduled for total knee arthroplasty were enrolled in the study. TNF-alpha and MMP-13 levels were measured preoperatively from venous blood samples and intraoperatively from knee synovial fluid via ELISA. Preoperative and 1 month postoperative knee functions were assessed by McMaster Universities Arthritis Index.

Results

Grade 4 synovial fluid MMP-13 (4.76 ± 5.82) was elevated compared to grade 3 (3.95 ± 4.45) (p = 0.438), whereas grade 3 serum MMP-13 (1.128 ± 0.308) was found elevated compared to grade 4 (1.038 ± 0.204) (p = 0.430). Grade 4 serum TNF-α (0.253 ± 0.277) was elevated compared to grade 3 (0.206 ± 0.219) whereas grade 3 synovial fluid TNF-α (0.129 ± 0.052) was elevated compared to grade 4 (0.118 ± 0.014). Positive correlation was observed between synovial fluid MMP-13 levels and postoperative WOMAC scores. Mean serum TNF-α level (0.226 ± 0.246 pg/ml) was found higher compared to synovial level (0.124 ± 1.59), synovial MMP-13 level (4.31 ± 1.24) was found higher compared to serum level (1.089 ± 1.519).

Conclusion

Despite the systemic increase in TNF-α levels concordant with osteoarthritis grade, MMP-13 levels are elevated via local manner with a significant correlation with WOMAC scores.

Level of evidence

Level IV, Diagnostic study.

MicroRNA221-3p modulates Ets-1 expression in synovial fibroblasts from patients with osteoarthritis of temporomandibular joint

OBJECTIVE

This study aimed to screen differential expression of microRNAs (miRNAs), and investigate function of the specifically selected miRNA in synovial fibroblasts from patients suffering osteoarthritis of temporomandibular joint (TMJOA).

METHODS

MiRNA microarray was used to select differentially expressed miRNAs between TMJOA and normal synovial fibroblasts. The expression of screened miRNA221-3p was quantified using real-time PCR, and its specific target gene was predicted by bioinformatics. After transfection of miRNA221-3p mimics or inhibitor into synovial fibroblasts, the expression of v-Ets avian erythroblastosis virus E26 oncogene homolog 1 (Ets-1) was detected by immunohistochemistry, real-time PCR and Western blot, respectively. Dual luciferase activity was performed to identify the direct regulation of miRNA221-3p on Ets-1. Interlukin-1β (IL-1β) mimics an inflammatory situation.

RESULTS

In TMJOA synovial fibroblasts, eight miRNAs were up-regulated and six miRNAs were down-regulated. MiRNA221-3p was the most down-expressed. A sequence in the 3'-untranslated (3'-UTR) of Ets-1 complementary to the seed sequence of miRNA221-3p. Elevated expression of Ets-1 associated with attenuation of miRNA221-3p. Over-expression of miRNA221-3p suppressed the activity of a reporter construct containing the 3'-UTR of Ets-1 transcript and inhibited the expression of Ets-1 as well as its downstream molecules, matrix metalloproteinase 1 (MMP1) and MMP9 in TMJOA synovial fibroblasts. IL-1β suppressed the expression of miRNA221-3p in both a dose-dependent and time-dependent manner.

CONCLUSION

The reduction of miRNA221-3p in synovial fibroblasts, attributed from abundance of IL-1β in inflamed circumstance, induces Ets-1 up-regulation and then, initiates MMP1 and MMP9 secretion, thereby leading to continuously pathological development in TMJOA.

The Role of MicroRNAs and Their Targets in Osteoarthritis

Micro ribonucleic acid (microRNA) regulation and expression has become an emerging field in determining the mechanisms regulating a variety of inflammation-mediated diseases. Several studies have focused on specific microRNAs that are differentially expressed in cases of osteoarthritis. Furthermore, several targets of these miRNAs important in disease progression have also been identified. In this review, we focus on microRNA biogenesis, regulation, detection, and quantification with an emphasis on cellular localization and how these concepts may be linked to disease processes such as osteoarthritis. Next, we review the relationships of specific microRNAs to certain features and risk factors associated with osteoarthritis such as inflammation, obesity, autophagy, and cartilage homeostasis. We also identify certain microRNAs that are differentially expressed in osteoarthritis but have unidentified targets and functions in the disease state. Lastly, we identify the potential use of microRNAs for therapeutic purposes and also mention certain remedies that regulate microRNA expression.

MicroRNA-320 regulates matrix metalloproteinase-13 expression in chondrogenesis and interleukin-1β-induced chondrocyte responses

OBJECTIVE

Metalloproteinases (MMPs) are key regulators of osteoarthritis (OA) and collagen degradation and have been shown to participate in endochondral ossification. The aim of this study was to determine whether microRNA-320 (miR-320) regulates the expression of MMP-13 in chondrogenesis and inflammation.

EXPERIMENTAL DESIGN

miR-320 expression was assessed in vitro, in the ATDC5 cell model of chondrogenesis and in interleukin-1β (IL-1β)-treated primary mouse chondrocytes (PMCs), and in vivo, in normal and OA human cartilage by in situ hybridization. ATDC5 and PMCs were transfected with miR-320 or its antisense inhibitor (anti-miR-320), respectively. The roles of activated MAP kinases (MAPK) and NF-κB were evaluated by using specific inhibitors. Direct interaction between miR-320 and its putative binding site in the 3'-untranslated region (3'-UTR) of Mmp-13 mRNA was confirmed by the luciferase reporter assay.

RESULTS

miR-320 expression was elevated in chondrogenic and hypertrophic ATDC5, while significantly reduced in OA cartilage compared with normal cartilage. Stimulation with IL-1β led to a significant reduction in miR-320 expression in PMCs. Upregulation of MMP-13 expression was correlated with downregulation of miR-320 expression in both PMCs and ATDC5. Overexpression of miR-320 suppressed the activity of a reporter construct containing the 3'-UTR and inhibited MMP-13 expression in both ATDC5 and IL-1β-treated PMCs, while treatment with anti-miR-320 enhanced MMP-13 expression. NF-κB and MAPK activation downregulated miR-320 expression.

CONCLUSION

Cartilage development and homeostasis are influenced by miR-320, which directly targets MMP-13 and regulates chondrogenesis and the IL-1β-stimulated catabolic effect in mouse chondrocytes.

The Role of miRNAs in Cartilage Homeostasis

Osteoarthritis (OA) is an age-related disease with poorly understood pathogenesis. Recent studies have demonstrated that miRNA might play a key role in OA initiation and development. We reviewed recent publications and elucidated the connection between miRNA and OA cartilage anabolic and catabolic signals, including four signaling pathways: TGF-β/Smads and BMPs signaling, associated with cartilage anabolism; and MAPK and NF-KB signaling, associated with cartilage catabolism. We also explored the relationships with MMP, ADAMTS and NOS (NitricOxide Synthases) families, as well as with the catabolic cytokines IL-1 and TNF-α. The potential role of miRNAs in biological processes such as cartilage degeneration, chondrocyte proliferation, and differentiation is discussed. Collective evidence indicates that miRNAs play a critical role in cartilage degeneration. These findings will aid in understanding the molecular network that governs articular cartilage homeostasis and in to elucidate the role of miRNA in the pathogenesis of OA.

MicroRNA-127-5p regulates osteopontin expression and osteopontin-mediated proliferation of human chondrocytes

The aim of this study was to determine the specific microRNA (miRNA) that regulates expression of osteopontin (OPN) in osteoarthritis (OA). The potential regulatory miRNAs for OPN messenger RNA (mRNA) were predicted by miRNA prediction programs. Among eight potential regulatory miRNAs, miR-220b, miR-513a-3p and miR-548n increased, while miR-181a, miR-181b, miR-181c, miR-181d and miR-127-5p decreased in OA patients. miRNA-127-5p mimics suppressed OPN production as well as the activity of a reporter construct containing the 3'-UTR of human OPN mRNA. In addition, mutation of miR-127-5p binding site in the 3'-UTR of OPN mRNA abolished miR-127-5p-mediated repression of reporter activity. Conversely, treatment with miR-127-5p inhibitor increased reporter activity and OPN production. Interestingly, miR-127-5p inhibited proliferation of chondrocytes through OPN. In conclusion, miRNA-127-5p is an important regulator of OPN in human chondrocytes and may contribute to the development of OA.

MMP-13 is constitutively produced in human chondrocytes and co-endocytosed with ADAMTS-5 and TIMP-3 by the endocytic receptor LRP1

Matrix metalloproteinase 13 (MMP-13) degrades collagenous extracellular matrix and its aberrant activity associates with diseases such as arthritis, cancer, atherosclerosis and fibrosis. The wide range of MMP-13 proteolytic capacity suggests that it is a powerful, potentially destructive proteinase and thus it has been believed that MMP-13 is not produced in most adult human tissues in the steady state. Present study has revealed that human chondrocytes isolated from healthy adults constitutively express and secrete MMP-13, but that it is rapidly endocytosed and degraded by chondrocytes. Both pro- and activated MMP-13 bind to clusters II and III of low-density lipoprotein (LDL) receptor-related protein 1 (LRP1). Domain deletion studies indicated that the hemopexin domain is responsible for this interaction. Binding competition between MMP-13 and ADAMTS-4, -5 or TIMP-3, which also bind to cluster II, further shown that the MMP-13 binding site within cluster II is different from those of ADAMTS-4, -5 or TIMP-3. MMP-13 is therefore co-endocytosed with ADAMTS-5 and TIMP-3 by human chondrocytes. These findings indicate that MMP-13 may play a role on physiological turnover of cartilage extracellular matrix and that LRP1 is a key modulator of extracellular levels of MMP-13 and its internalization is independent of the levels of ADAMTS-4, -5 and TIMP-3.

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ProMMP-13 is constitutively produced and endocytosed by chondrocytes.

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LRP1 is a key modulator of extracellular levels of proMMP-13 and MMP-13.

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ProMMP-13 and MMP-13 directly bind to LRP1 via the hemopexin domain.

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Unique sites on LRP1 for MMP-13 binding have been mapped.

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Co-endocytosis of proMMP-13 with ADAMTS-4, -5 and TIMP-3.

MicroRNAs: exploring new horizons in osteoarthritis

INTRODUCTION

Osteoarthritis (OA) is a common disease worldwide leading to significant morbidity. The underlying disease process is multifactorial however there is increasing focus on molecular mechanisms. MicroRNAs are small non-coding segments of RNA that have important regulatory functions at a cellular level. These molecules are readily detectable in human tissues and circulation. They are increasingly recognised as having a major role in many disease processes - including malignancy and inflammatory processes.

OBJECTIVE

This review paper aims to provide a comprehensive update on the evidence for miRNA roles in OA.

DESIGN

A comprehensive literature search was performed using key medical subject headings (MeSH) terms 'microRNA' and 'osteoarthritis'.

RESULTS

Several miRNAs have been identified as having aberrant expression levels in OA. Some of these include miR-9, miR-27, miR-34a, miR-140, miR-146a, miR-558 and miR-602. Many of the dysregulated miRNAs have been shown to regulate expression of inflammatory pathways such as interleukin-mediated or matrix metalloproteinase-13 (MMP-13)-mediated degradation of the articular cartilage extracellular matrix (ECM). MiRNAs may also play a role in pain pathways and hence expression of clinical symptoms.

CONCLUSIONS

Recent evidence has shown that miRNAs in the circulation may reflect underlying disease states and hence serve as potential markers for disease activity. These findings may represent possible future therapeutic applications in the management of OA.

Overexpression of microRNA-634 suppresses survival and matrix synthesis of human osteoarthritis chondrocytes by targeting PIK3R1

Osteoarthritis (OA) is a degenerative disease characterized by deterioration of articular cartilage. Recent studies have demonstrated the importance of some microRNAs in cartilage damage. The aim of this study was to identify and characterize the expression of microRNA-634 (miR-634) in normal and OA chondrocytes, and to determine its role in OA pathogenesis. Human normal and OA chondrocytes obtained from patients were cultured in vitro. Transfection with miR-634 mimic or inhibitor was employed to investigate the effect of miR-634 on chondrocyte survival and matrix synthesis, and to identify miR-634 target. The results indicated that miR-634 was expressed at lower level in high grade OA chondrocyte compared with normal chondrocytes. Overexpression of miR-634 could inhibit cell survival and matrix synthesis in high grade OA chondrocytes. Furthermore, miR-634 targeted PIK3R1 gene that encodes the regulatory subunit 1 of class I PI3K (p85α) and exerted its inhibitory effect on the phosphorylation of Akt, mTOR, and S6 signal molecules in high grade OA chondrocytes. Therefore, the data suggested that miR-634 could suppress survival and matrix synthesis of high grade OA chondrocytes through targeting PIK3R1 gene to modulate the PI3K/Akt/S6 and PI3K/Akt/mTOR/S6 axes, with important implication for validating miR-634 as a potential target for OA therapy.

Overexpression of microRNA-210 promotes chondrocyte proliferation and extracellular matrix deposition by targeting HIF-3α in osteoarthritis

The present study aimed to determine the effect of microRNA (miR)‑210 on osteoarthritis (OA). The expression levels of miR‑210, type I and X collagen (COL1A1 and COL10A1) and matrix metallopeptidase 13 (MMP13) in OA and normal chondrocytes were determined using reverse transcription‑quantitative polymerase chain reaction analysis. The OA chondrocytes were transfected with an miRNA precursor for miR‑210 or a negative control. After 3, 7, 14 and 21 days, the expression levels of miR‑210 were examined, the proliferation of the OA chondrocytes were determined using an XTT assay and the protein levels of Ki67 and HIF‑3α were analyzed by Western blotting. After 21 days, the mRNA and protein levels of COL1A1, COL10A1 and MMP13 were analyzed. Th present study demonstrated that the expression levels of miR‑210 and COL1A1 were lower, and the expression levels of COL10A1 and MMP13 were higher in the OA chondrocytes, compared with the levels of expression in the normal chondrocytes. Overexpression of miR‑210 significantly promoted the proliferation of OA chondrocytes and induced the protein expression of Ki67. In addition, miR‑210 overexpression markedly increased the expression of COL1A1 expression, but decreased the expression levels of COL10A1 and MMP13. A luciferase reporter assay confirmed the direct interaction between miR‑210 and hypoxia‑inducible factor (HIF)‑3α. miR‑210 did not alter the mRNA expression of HIF‑3α, however, it suppressed the protein expression of HIF‑3α. Additionally, HIF‑3α knockdown significantly promoted OA chondrocyte proliferation and increased the mRNA levels of COL1A1, whereas it decreased the mRNA levels of COL10A1 and MMP13. The results of the present study suggested that miR‑210 may be a negative regulator of the progression of OA, which increases chondrocyte proliferation and prompts extracellular matrix deposition by directly targeting HIF‑3α.

MiR-29a and MiR-140 Protect Chondrocytes against the Anti-Proliferation and Cell Matrix Signaling Changes by IL-1β

As a degenerative joint disease, osteoarthritis (OA) constitutes a major cause of disability that seriously affects the quality of life of a large population of people worldwide. However, effective treatment that can successfully reverse OA progression is lacking until now. The present study aimed to determine whether two small non-coding RNAs miR-29a and miR-140, which are significantly down-regulated in OA, can be applied together as potential therapeutic targets for OA treatment. MiRNA synergy score was used to screen the miRNA pairs that potentially synergistically regulate OA. An in vitro model of OA was established by treating murine chondrocytes with IL-1β. Transfection of miR-29a and miR-140 via plasmids was investigated on chondrocyte proliferation and expression of nine genes such as ADAMTS4, ADAMTS5, ACAN, COL2A1, COL10A1, MMP1, MMP3, MMP13 and TIMP metal-lopeptidase inhibitor 1 (TIMP1). Western blotting was used to determine the protein expression level of MMP13 and TIMP1, and ELISA was used to detect the content of type II collagen. Combined use of miR-29a and miR-140 successfully reversed the destructive effect of IL-1β on chondrocyte proliferation, and notably affected the MMP13 and TIMP1 gene expression that regulates extracellular matrix. Although co-transfection of miR-29a and miR-140 did not show a synergistic effect on MMP13 protein expression and type II collagen release, but both of them can significantly suppress the protein abundance of MMP13 and restore the type II collagen release in IL-1β treated chondrocytes. Compared with single miRNA transfection, cotransfection of both miRNAs exceedingly abrogated the suppressed the protein production of TIMP1 caused by IL-1β, thereby suggesting potent synergistic action. These results provided novel insights into the important function of miRNAs' collaboration in OA pathological development. The reduced MMP13, and enhanced TIMP1 protein production and type II collagen release also implies that miR-29a and miR-140 combination treatment may be a possible treatment for OA.

MiR-502-5p inhibits IL-1β-induced chondrocyte injury by targeting TRAF2

Osteoarthritis (OA) is characterized by articular cartilage degradation and joint inflammation. MicroRNAs have been proven to play an important role in the regulation of chondrogenesis. The aim of the present study was to investigate the effect of miR-502-5p in OA. The results showed that miR-502-5p levels were significantly down-regulated in OA articular tissues and IL-1β-induced chondrocytes compared with control groups. MiR-502-5p overexpression inhibited IL-1β-induced reduction in cell viability and increase in cell apoptosis, and alleviated IL-1β-induced extracellular matrix (ECM) metabolic imbalance and pro-inflammatory cytokine production. MiR-502-5p targeted the 3'-untranslated region (UTR) of TRAF2 to inhibit its expression. The IL-1β-induced activation of NF-κB signaling pathway was inhibited by PDTC, an inhibitor of NF-κB, which was also suppressed by the miR-502-5p mimic and TRAF2 siRNA transfection. In conclusion, miR-502-5p may exhibit a protective effect on IL-1β-induced chondrocyte injury by targeting TRAF2 and inhibiting NF-κB signaling pathway.

Biological Response Modifier in Cancer Immunotherapy

Biological response modifiers (BRMs) emerge as a lay of new compounds or approaches used in improving cancer immunotherapy. Evidences highlight that cytokines, Toll-like receptor (TLR) signaling, and noncoding RNAs are of crucial roles in modulating antitumor immune response and cancer-related chronic inflammation, and BRMs based on them have been explored. In particular, besides some cytokines like IFN-α and IL-2, several Toll-like receptor (TLR) agonists like BCG, MPL, and imiquimod are also licensed to be used in patients with several malignancies nowadays, and the first artificial small noncoding RNA (microRNA) mimic, MXR34, has entered phase I clinical study against liver cancer, implying their potential application in cancer therapy. According to amounts of original data, this chapter will review the regulatory roles of TLR signaling, some noncoding RNAs, and several key cytokines in cancer and cancer-related immune response, as well as the clinical cases in cancer therapy based on them.

Identification of differential microRNA expression during tooth morphogenesis in the heterodont dentition of miniature pigs, SusScrofa

Background

It has been found that microRNAs (miRNAs) play important roles in the regulation of tooth development, and most likely increase the complexity of the genetic network, thus lead to greater complexity of teeth. But there has been no research about the key microRNAs associated with tooth morphogenesis based on miRNAs expression profiles. Compared to mice, the pig model has plentiful types of teeth, which is similar with the human dental pattern. Therefore, we used miniature pigs as large-animal models to investigate differentially expressed miRNAs expression during tooth morphogenesis in the early developmental stages of tooth germ.

Results

A custom-designed miRNA microarray with 742 miRNA gene probes was used to analyze the expression profiles of four types of teeth at three stages of tooth development. Of the 591 detectable miRNA transcripts, 212 miRNAs were continuously expressed in all types of tooth germ, but the numbers of miRNA transcript among the four different types of teeth at each embryonic stage were statistically significant differences (p < 0.01). The hierarchical clustering and principal component analysis results suggest that the miRNA expression was globally altered by types and temporal changes. By clustering analysis, we predicted 11 unique miRNA sequences that belong to mir-103 and mir-107, mir-133a and mir-133b, and mir-127 isomiR families. The results of real-time reverse-transcriptase PCR and in situ hybridization experiments revealed that five representative miRNAs may play important roles during different developmental stages of the incisor, canine, biscuspid, and molar, respectively.

Conclusions

The present study indicated that these five miRNAs, including ssc-miR-103 and ssc-miR-107, ssc-miR-133a and ssc-miR-133b, and ssc-miR-127, may play key regulatory roles in different types of teeth during different stages and thus may play critical roles in tooth morphogenesis during early development in miniature pigs.

Electronic supplementary material

The online version of this article (doi:10.1186/s12861-015-0099-0) contains supplementary material, which is available to authorized users.

The role of inflammation-related genes in osteoarthritis

In this review article we examine the role of inflammation-related genes in osteoarthritis (OA) from the perspective of genetics, epigenetics and gene expression. There have been great strides in such genomic analyses of OA in recent years thanks to the study of adequately powered patient cohorts, the detailed analysis of candidate genes, and the application of genome-wide approaches. These have led to some unexpected and therefore exciting discoveries, implicating pathways that would not necessarily have been predicted to have a role in this common arthritis. Inflammatory-related genes sit firmly in the candidate camp based on prior observations that the OA disease process can have an inflammatory component. What is clear from the genetic studies published to date is that there is no compelling evidence that DNA variation in inflammatory genes is an OA risk factor. This conclusion may of course change as ever more powerful association studies are conducted. There is, however, compelling evidence that epigenetic effects involving inflammatory genes are a component of OA and that alteration in the expression of these genes is also highly relevant to the disease process. We may in fact be close to demonstrating, at the genomic level, a clear separation of OA patients into those in whom inflammation is a key driver of the disease and those in whom it is not. This has obvious implications for the design of trials of novel OA interventions and may also guide the intelligent re-purposing of anti-inflammatory therapies.

MicroRNAs' Involvement in Osteoarthritis and the Prospects for Treatments

Osteoarthritis (OA) is a chronic disease and its etiology is complex. With increasing OA incidence, more and more people are facing heavy financial and social burdens from the disease. Genetics-related aspects of OA pathogenesis are not well understood. Recent reports have examined the molecular mechanisms and genes related to OA. It has been realized that genetic changes in articular cartilage and bone may contribute to OA's development. Osteoclasts, osteoblasts, osteocytes, and chondrocytes in joints must express appropriate genes to achieve tissue homeostasis, and errors in this can cause OA. MicroRNAs (miRNAs) are small noncoding RNAs that have been discovered to be overarching regulators of gene expression. Their ability to repress many target genes and their target-binding specificity indicate a complex network of interactions, which is still being defined. Many studies have focused on the role of miRNAs in bone and cartilage and have identified numbers of miRNAs that play important roles in regulating bone and cartilage homeostasis. Those miRNAs may also be involved in the pathology of OA, which is the focus of this review. Future studies on the role of miRNAs in OA will provide important clues leading to a better understanding of the mechanism(s) of OA and, more particularly, to the development of therapeutic targets for OA.

Adult human neural crest-derived cells for articular cartilage repair

In embryonic models and stem cell systems, mesenchymal cells derived from the neuroectoderm can be distinguished from mesoderm-derived cells by their Hox-negative profile--a phenotype associated with enhanced capacity of tissue regeneration. We investigated whether developmental origin and Hox negativity correlated with self-renewal and environmental plasticity also in differentiated cells from adults. Using hyaline cartilage as a model, we showed that adult human neuroectoderm-derived nasal chondrocytes (NCs) can be constitutively distinguished from mesoderm-derived articular chondrocytes (ACs) by lack of expression of specific HOX genes, including HOXC4 and HOXD8. In contrast to ACs, serially cloned NCs could be continuously reverted from differentiated to dedifferentiated states, conserving the ability to form cartilage tissue in vitro and in vivo. NCs could also be reprogrammed to stably express Hox genes typical of ACs upon implantation into goat articular cartilage defects, directly contributing to cartilage repair. Our findings identify previously unrecognized regenerative properties of HOX-negative differentiated neuroectoderm cells in adults, implying a role for NCs in the unmet clinical challenge of articular cartilage repair. An ongoing phase 1 clinical trial preliminarily indicated the safety and feasibility of autologous NC-based engineered tissues for the treatment of traumatic articular cartilage lesions.

Cartilage tissue engineering: recent advances and perspectives from gene regulation/therapy

Diseases in articular cartilages affect millions of people. Despite the relatively simple biochemical and cellular composition of articular cartilages, the self-repair ability of cartilage is limited. Successful cartilage tissue engineering requires intricately coordinated interactions between matrerials, cells, biological factors, and phycial/mechanical factors, and still faces a multitude of challenges. This article presents an overview of the cartilage biology, current treatments, recent advances in the materials, biological factors, and cells used in cartilage tissue engineering/regeneration, with strong emphasis on the perspectives of gene regulation (e.g., microRNA) and gene therapy.

MicroRNA-602 and microRNA-608 regulate sonic hedgehog expression via target sites in the coding region in human chondrocytes

OBJECTIVE

Hedgehog (HH) signaling has recently been associated with cartilage degradation in osteoarthritis (OA). Because interleukin-1β (IL-1β) has been implicated as a principal instigator of OA, we sought to determine whether IL-1β induces the expression of sonic HH (SHH) and its regulation by microRNAs (miRNAs) in human chondrocytes.

METHODS

Expression of SHH protein in human OA cartilage and in an animal model of OA was determined by immunohistochemical analysis and immunofluorescence analysis, respectively. Gene and protein expression in IL-1β- or SHH-stimulated OA chondrocytes was determined by TaqMan assays and Western blotting, respectively. The effect of overexpression of miRNA-602 (miR-602) and miR-608 or their antagomirs on SHH expression was evaluated by transient transfection of human chondrocytes and HEK 293 cells. The role of signaling pathways was evaluated using small molecule inhibitors. Binding of miRNAs with the putative seed sequence in SHH messenger RNA (mRNA) was validated using a luciferase reporter assay.

RESULTS

Expression of SHH, patched 1, Gli-1, HH-interacting protein, matrix metalloproteinase 13 (MMP-13), and Colα1(X) was high in damaged OA cartilage. In damaged cartilage and in IL-1β-stimulated OA chondrocytes, expression of SHH was inversely correlated with expression of miR-608. Cotransfection of OA chondrocytes with miR-608 or miR-602 mimic inhibited reporter activity, and mutation of the miRNA seed sequences abolished the repression of reporter activity. Overexpression of miR-602 or miR-608 inhibited the expression of SHH mRNA and protein, and this was abrogated by antagomirs. Stimulation with recombinant human SHH protein up-regulated MMP-13 expression, and inhibition of HH signaling blocked MMP-13 expression in OA chondrocytes.

CONCLUSION

MiR-602 and miR-608 are important posttranscription regulators of SHH expression in OA chondrocytes, and their suppression by IL-1β may contribute to the enhanced expression of SHH and MMP-13 in OA.

Expression profile of long noncoding RNAs in cartilage from knee osteoarthritis patients

OBJECTIVES

Long noncoding RNAs (lncRNAs) have emerged as a novel class of regulatory molecules involved in various biological processes, but their role in osteoarthritis (OA) remains unknown. Therefore, we aimed to reveal lncRNAs expression profile in human osteoarthritic cartilage and explore the potential functions of lncRNAs in OA.

METHODS

The expression profiles of lncRNAs and mRNAs in OA cartilage were obtained using microarray and verified by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Bioinformatics analyses including lncRNA classification and subgroup analysis, gene ontology (GO) analysis, pathway analysis, network analysis and target prediction were performed.

RESULTS

There were 3007 upregulated lncRNAs and 1707 downregulated lncRNAs in OA cartilage compared with normal samples (Fold change ≥ 2.0). In addition, 2136 mRNAs were upregulated and 2,241 mRNAs were downregulated in OA cartilage (Fold change ≥ 2.0). The qRT-PCR results of six dysregulated lncRNAs were consistent with the microarray data. 106 lncRNAs and 291 mRNAs composed the coding-non-coding gene co-expression network (CNC network). In the 600 top differentially expressed lncRNAs, 48 lncRNAs were predicted to have more than five cis-regulated target genes and up to 530 lncRNAs might regulate their trans target genes through collaboration with transcriptional factor (TF) SP1. The positive correlation between lncRNA uc.343 and predicted target homeobox gene C8 (HOXC8) expression in SW1353 cells treating with interleukin-1 beta confirmed the target prediction to some extent.

CONCLUSIONS

This study revealed the expression pattern of lncRNAs in OA cartilage and predicted the potential function and targets, which indicated that lncRNAs may be new biomarkers for diagnosis or novel therapeutic targets of OA.

Mechanisms and applications of interleukins in cancer immunotherapy

Over the past years, advances in cancer immunotherapy have resulted in innovative and novel approaches in molecular cancer diagnostics and cancer therapeutic procedures. However, due to tumor heterogeneity and inter-tumoral discrepancy in tumor immunity, the clinical benefits are quite restricted. The goal of this review is to evaluate the major cytokines-interleukins involved in cancer immunotherapy and project their basic biochemical and clinical applications. Emphasis will be given to new cytokines in pre-clinical development, and potential directions for future investigation using cytokines. Furthermore, current interleukin-based approaches and clinical trial data from combination cancer immunotherapies will also be discussed. It appears that continuously increasing comprehension of cytokine-induced effects, cancer stemness, immunoediting, immune-surveillance as well as understanding of molecular interactions emerging in the tumor microenvironment and involving microRNAs, autophagy, epithelial-mesenchymal transition (EMT), inflammation, and DNA methylation processes may hold much promise in improving anti-tumor immunity. To this end, the emerging in-depth knowledge supports further studies on optimal synergistic combinations and additional adjuvant therapies to realize the full potential of cytokines as immunotherapeutic agents.

Mechanisms and applications of interleukins in cancer immunotherapy

Over the past years, advances in cancer immunotherapy have resulted in innovative and novel approaches in molecular cancer diagnostics and cancer therapeutic procedures. However, due to tumor heterogeneity and inter-tumoral discrepancy in tumor immunity, the clinical benefits are quite restricted. The goal of this review is to evaluate the major cytokines-interleukins involved in cancer immunotherapy and project their basic biochemical and clinical applications. Emphasis will be given to new cytokines in pre-clinical development, and potential directions for future investigation using cytokines. Furthermore, current interleukin-based approaches and clinical trial data from combination cancer immunotherapies will also be discussed. It appears that continuously increasing comprehension of cytokine-induced effects, cancer stemness, immunoediting, immune-surveillance as well as understanding of molecular interactions emerging in the tumor microenvironment and involving microRNAs, autophagy, epithelial-mesenchymal transition (EMT), inflammation, and DNA methylation processes may hold much promise in improving anti-tumor immunity. To this end, the emerging in-depth knowledge supports further studies on optimal synergistic combinations and additional adjuvant therapies to realize the full potential of cytokines as immunotherapeutic agents.

MicroRNAs in cartilage development, homeostasis, and disease

microRNAs (miRNAs) regulate gene expression mainly at the posttranscriptional level. Many different miRNAs are expressed in chondrocytes, and each individual miRNA can regulate hundreds of target genes, creating a complex gene regulatory network. Experimental evidence suggests that miRNAs play significant roles in various aspects of cartilage development, homeostasis, and pathology. The possibility that miRNAs can be novel therapeutic targets for cartilage diseases led to vigorous investigations to understand the role of individual miRNAs in skeletal tissues. Here, we summarize our current understanding of miRNAs in chondrocytes and cartilage. In the first part, we discuss roles of miRNAs in growth plate development and chondrocyte differentiation. In the second part, we put a particular focus on articular cartilage and discuss the significance of variety of findings in the context of osteoarthritis, the most common degenerative joint disease.

Osteoarthritis year in review 2014: genetics and genomics

Recent developments in genetics/genomics of osteoarthritis (OA) are discussed to improve our understanding of OA pathophysiology. The discovery of a novel variant near the NCOA3 (nuclear receptor coactivator 3) gene associated with hip OA and the regulation of GDF5 gene by four transcription factors via the OA susceptibility locus rs143383 are among important findings in OA genetics. Several microarray-based gene expression studies were published for different tissues of the joint. In OA synovium elevation of collagens and cross-linking enzymes (COL1A1, COL5A1, PLOD2, LOX and TIMP1) responsive to TGF-β was found as well as differential expression pattern between different areas of the osteoarthritic synovial membrane. In OA peripheral blood the role of apoptotic genes was highlighted, while whole genome expression profiling in OA subchondral bone and cartilage revealed common genes in cartilage and bone to be involved in OA development. In epigenetics, several microRNAs (miRNAs) were found to regulate genes' expression in chondrocytes, among which miR-125, miR-127b miR-21, miR-148a and their use as potential drug targets was highlighted. Future studies must focus on the integration of genetics, genomics and epigenetics for the identification of signaling pathways and regulatory networks responsible for OA development.

MicroRNAs and post-transcriptional regulation of skeletal development

MicroRNAs (miRNAs) have become integral nodes of post-transcriptional control of genes that confer cellular identity and regulate differentiation. Cell-specific signaling and transcriptional regulation in skeletal biology are extremely dynamic processes that are highly reliant on dose-dependent responses. As such, skeletal cell-determining genes are ideal targets for quantitative regulation by miRNAs. So far, large amounts of evidence have revealed a characteristic temporal miRNA signature in skeletal cell differentiation and confirmed the essential roles that numerous miRNAs play in bone development and homeostasis. In addition, microarray expression data have provided evidence for their role in several skeletal pathologies. Mouse models in which their expression is altered have provided evidence of causal links between miRNAs and bone abnormalities. Thus, a detailed understanding of the function of miRNAs and their tight relationship with bone diseases would constitute a powerful tool for early diagnosis and future therapeutic approaches.

MicroRNA-dependent targeting of the extracellular matrix as a mechanism of regulating cell behavior

BACKGROUND

MicroRNAs are small noncoding RNAs which regulate gene expression at the posttranscriptional level by inducing mRNA degradation or translational repression. MicroRNA-dependent modulation of the extracellular matrix and its cellular receptors has emerged as a novel mechanism of regulating numerous matrix-dependent processes, including cell proliferation and apoptosis, cell adhesion and migration, cell differentiation and stem cell properties.

SCOPE OF REVIEW

In this review, we will present different mechanisms by which microRNAs and extracellular matrix constituents mutually regulate their expression, and we will demonstrate how these expression changes affect cell behavior. We will also highlight the importance of dysregulated matrix-related microRNA expression for the pathogenesis of inflammatory and malignant disease, and discuss the potential for diagnostic and therapeutic applications.

MAJOR CONCLUSIONS

MicroRNAs and matrix-dependent signal transduction processes form novel regulatory circuits, which profoundly affect cell behavior. As misexpression of microRNAs targeting extracellular matrix constituents is observed in a variety of diseases, a pharmacological intervention with these processes has therapeutic potential, as successfully demonstrated in vitro and in advanced animal models. However, a deeper mechanistic understanding is required to address potential side effects prior to clinical applications in humans.

GENERAL SIGNIFICANCE

A full understanding of the role and function of microRNA-dependent regulation of the extracellular matrix may lead to new targeted therapies and new diagnostics for malignant and inflammatory diseases in humans. This article is part of a Special Issue entitled Matrix-mediated cell behaviour and properties.