Circular RNAs (circRNAs) are currently classed as non-coding RNAs that, unlike the better known canonical linear RNAs, form a covalently closed continuous loop without 5′ or 3′ polarities. With the development of high throughput sequencing technology, a large number of circRNAs have been discovered in many species. More importantly, growing evidence suggests that circRNAs are abundant, evolutionally conserved, and relatively stable in cells and tissues. Strikingly, recent studies have discovered that circRNAs can serve as microRNA sponges, interact with RNA-binding protein, and regulate gene transcription, as well as protein translation. Osteoarthritis (OA) is the most common chronic degenerative joint disease. CircRNAs are differentially expressed in OA cartilage. Moreover, some circRNAs are involved in multiple pathological processes during OA, mainly extracellular matrix degradation, inflammation, and apoptosis. In this review, we briefly delineate the biogenesis, characteristics, and biofunctions of circRNAs, and then, focus on the role of circRNAs in the occurrence and progression OA.
Apoptosis ; Cartilage ; Cartilage, Articular ; Extracellular Matrix ; Inflammation ; Joint Diseases ; MicroRNAs ; Osteoarthritis* ; Pathologic Processes ; Porifera ; Protein Biosynthesis ; RNA* ; RNA, Untranslated ; RNA-Binding Proteins

OBJECTIVETo analyze microarray datasets deposited in the public database and to identify TNM associated genes in gastric cancers.

METHODSMicroarray datasets of gastric cancer were selected from GEO database. Differentially expressed genes related to TNM staging were evaluated by significant analysis of the microarray using MultiExperiment Viewer (MEV) platform. Candidate gene expressions in gastric cancer tissues and cell lines were verified by reverse transcriptase polymerase chain reaction (RT-PCR), quantitative RT-PCR, Western blot and immunohistochemistry.

RESULTSGES4007 dataset was re-analyzed leading to the identification of 14 genes associated with TNM staging. Over-expression of matrix gla protein (MGP) was confirmed in gastric cancer cell lines and tumor tissues by quantitative RT-PCR, Western blot and immunohistochemistry. Increased MGP expression was found in 22 of 54 cases of (40.7%) gastric cancer specimens compared to the normal gastric tissues. The up-regulation of MGP mRNA expression closely correlated with TNM stage (P = 0.001) and prognosis (P = 0.006).

CONCLUSIONSPublic databases of microarray studies are the valuable resources for data mining. MGP has been identified and confirmed as a novel biomarker for the TNM stage and prognosis of gastric cancer.

Adult ; Aged ; Biomarkers, Tumor ; genetics ; metabolism ; Calcium-Binding Proteins ; biosynthesis ; genetics ; Cell Line, Tumor ; Extracellular Matrix Proteins ; biosynthesis ; genetics ; Female ; Follow-Up Studies ; Gene Expression Profiling ; Gene Expression Regulation, Neoplastic ; Humans ; Lymphatic Metastasis ; Male ; Middle Aged ; Neoplasm Staging ; Oligonucleotide Array Sequence Analysis ; RNA, Messenger ; metabolism ; Stomach Neoplasms ; genetics ; metabolism ; pathology ; Survival Rate ; Up-Regulation ; Young Adult

Wnt inhibitor factor-1 (WIF-1) is an extracellular antagonist of Wnts secreted proteins, first characterized as an expressed sequence tag in the human retina. WIF-1 belongs to the secreted Frizzled-related protein (sFRP) class, which can directly bind to Wnt proteins, prevent Wnts from binding to their receptors in vertebrates. Wif1 is expressed in the nervous system of mouse, Xenopus, zebrafish and human. It has been shown that WIF-1 affects the formation of somites in Xenopus embryos and inhibits rod production in retinal histogenesis by binding to Wnt4 in mice. Histological information of Wif1 expression during the development of the central nervous system has been reported in mouse, Xenopus and zebrafish and the strong embryonic expression suggests Wif1 may play an essential role in the spatial and temporal regulation of Wnt signals in development of central nervous system. The Wnt pathway plays a key role in the patterning of the nervous system. However, insights into the function of Wif1 in the development of the central nervous system are rather limited. Selecting suitable stage and target according to the expression pattern may contribute to understanding the function of Wif1.
Adaptor Proteins, Signal Transducing ; biosynthesis ; physiology ; Animals ; Brain ; embryology ; metabolism ; Central Nervous System ; embryology ; metabolism ; Extracellular Matrix Proteins ; biosynthesis ; physiology ; Gene Expression ; Humans ; Intercellular Signaling Peptides and Proteins ; biosynthesis ; physiology ; Mice ; Repressor Proteins ; biosynthesis ; physiology ; Signal Transduction ; physiology ; Spinal Cord ; embryology ; metabolism ; Xenopus

BACKGROUND: The mechanism by which mutant cartilage oligomeric matrix protein (COMP) induces a pseudoachondroplasia phenotype remains unknown, and the reason why a mutation of a minor protein of the growth plate cartilage causes total disruption of endochondral bone formation has not yet been determined. The current study was performed to investigate the effects of mutated COMP on the synthesis of the cartilage-specific major matrix proteins of Swarm rat chondrosarcoma chondrocytes. METHODS: The Swarm rat chondrosarcoma chondrocytes transfected with a chimeric construct, which consisted of a mutant gene of human COMP and an amino acid FLAG tag sequence, were cultured in agarose gel. Formation of extracellular proteoglycan and type-II collagen by the cells was evaluated by immunohistochemical staining and measuring the (35)S-sulfate incorporation. RESULTS: No difference was observed for the detection of type-II collagen among the cell lines expressing mutant COMP and the control cell lines. Histochemical staining of sulfated proteoglycans with safranin-O showed that lesser amounts of proteoglycans were incorporated into the extracellular matrix of the chondrocytes transfected with the mutant gene. (35)S-sulfate incorporation into the cell/matrix fractions demonstrated markedly lower radiolabel incorporation, as compared to that of the control cells. CONCLUSIONS: Mutation of COMP has an important impact on the processing of proteoglycans, rather than type-II collagen, in the three-dimensional culture of Swarm rat chondrosarcoma chondrocytes.
Aggrecans/analysis/*biosynthesis ; Animals ; Cells, Cultured ; Chondrocytes/*metabolism ; Chondrosarcoma/metabolism ; Collagen Type II/*biosynthesis ; Extracellular Matrix/*metabolism ; Extracellular Matrix Proteins/*genetics ; Glycoproteins/*genetics ; Humans ; Mutation ; Rats ; Transfection

OBJECTIVETo investigate the interaction domains between macrophage migration inhibitory factors (MIF) and the extracellular segment of type-II trans-membrane protein CD74 using a yeast two-hybrid system.

METHODSBy using molecular cloning techniques, the DNA fragments encoding MIF, MIF(50-65) and MIF(1-50/65-115) were introduced into the pGBKT7 vector to construct the corresponding recombinant bait plasmids, and the DNA fragments encoding CD74(73-232), CD74(73-109), CD74(1109-149) and CD74(149-232) into the pGADT7 vector to construct the recombinant activation domain (AD) plasmids. PEG/LiAC method was employed to transform the above 3 recombinant bait plasmids paired with each of the 4 recombinant AD plasmids into the chemical competent yeast AH109 cells. The transformed yeast AH109 cells were screened consecutively on SD/-Trp-Leu and SD/-Trp-Leu-Ade-His/X-alpha-gal nutritional media.

RESULTSThe results of restriction endonuclease digestion and DNA sequencing verified the correct construction of all the recombinant plasmids. The yeast AH109 cells transformed with each of the 3 recombinant bait plasmids could grow on SD/-trp nutritional media without autonomous activation effect on the reporter gene MEL1. The cells transformed with each of the 4 recombinant AD plasmids could also grow on SD/-leu nutritional media without activation of the reporter gene MEL1. Only the yeast AH109 cells co-transformed with MIF, MIF(50-65), or MIF(1-50/65-115) plasmid and CD74(73-232) plasmid could grow on SD/-Trp-Leu-Ade-His nutritional media with transcription activation of the reporter gene MEL1.

CONCLUSIONMIF interacts with the intact extracellular segment of CD74 (CD74(73-232)) independent of the functional domain of MIF(50-65).

Antigens, Differentiation, B-Lymphocyte ; genetics ; metabolism ; Cloning, Molecular ; Escherichia coli ; genetics ; metabolism ; Extracellular Matrix ; metabolism ; Histocompatibility Antigens Class II ; genetics ; metabolism ; Macrophage Migration-Inhibitory Factors ; genetics ; metabolism ; Peptide Fragments ; genetics ; Protein Interaction Domains and Motifs ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Two-Hybrid System Techniques

The full-length cDNA of hTIMP-1 was obtained from a surgical patient with HCC by the method of RT-PCR. Then it was cloned into the adenoviral shuttle plasmid pAdTrack-CMV, and subsequently cotransformed into competent BJ5183 cells with the adenoviral backbone plasmid pAdEasy-1. Thereupon, a recombinant adenoviral plasmid containing full-length cDNA of hTIMP-1 was generated by homologous recombination in E. coli. The adenoviruses (AdhTIMP-1) were packaged and amplified in adenoviral packaging cells HEK 293. Then the viral titer was checked by green fluorescent protein (GFP), and the expression of hTIMP-1 was detected by the techniques of Western blot and RT-PCR. The recombinant adenovirus vector carrying human TIMP-1 was successfully constructed and expressed in vitro and may pave the way for further application in liver gene therapy.
Adenoviridae ; genetics ; metabolism ; Carcinoma, Hepatocellular ; metabolism ; Cell Line ; Cloning, Molecular ; DNA, Complementary ; genetics ; Extracellular Matrix ; metabolism ; Genetic Vectors ; Humans ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Tissue Inhibitor of Metalloproteinase-1 ; biosynthesis ; genetics

Diagnosis, Differential ; Drugs, Chinese Herbal ; therapeutic use ; Extracellular Matrix Proteins ; biosynthesis ; Humans ; Liver ; metabolism ; pathology ; Liver Cirrhosis ; drug therapy ; metabolism ; pathology ; Medicine, Chinese Traditional ; Phytotherapy

Conditions of disuse such as bed rest, space flight, and immobilization result in decreased mechanical loading of bone, which is associated with reduced bone mineral density and increased fracture risk. Mechanisms involved in this process are not well understood except the suppression of osteoblast function. To investigate the effect of simulated weightlessness on mRNA level of extracellular matrix proteins, osteoblasts were rotated in horizontal plane as a model of simulated microgravity. Primordial osteoblasts of rats were grown for 2 d and then rotated for 24, 48 and 72 h, respectively. After isolating total RNA in cells, reverse transcription polymerase chain reaction (PT-PCR) was made to examine the mRNA level of osteopontin (OPN) and osteonectin (ON). Meanwhile, the levels of alkaline phosphatase (ALP) and osteocalcin (BGP) in the cultured medium were measured to evaluate the calcific function of cell. The expression of OPN and ON mRNA fell significantly after rotating for 24, 48 and 72 h, respectively. The contents of BGP descended significantly, meanwhile, the activity of ALP also showed a degressive tendency. Horizontal rotation decreased the expression of ON and OPN as well as diminished the secretion of BGP and ALP, which affected the calcific function of osteoblast. The results obtained suggest that depression of extracellular matrix proteins expression plays a key role in bone loss during weightlessness.
Animals ; Animals, Newborn ; Cells, Cultured ; Extracellular Matrix Proteins ; biosynthesis ; genetics ; Osteoblasts ; cytology ; metabolism ; Osteonectin ; biosynthesis ; genetics ; Osteopontin ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Wistar ; Rotation ; Sialoglycoproteins ; biosynthesis ; genetics ; Skull ; cytology ; Weightlessness Simulation

CD137, which is expressed on activated T cells, plays a critical role in inflammatory responses. However, the exact role that CD137 plays in monocytes is not fully known. Here we studied the expression and function of CD137 in human monocytic THP-1 cells, which we found constitutively expresses CD137 at the mRNA and protein level. Cross-linking of CD137 increased the secretion of IL-8 and TNF-alpha, promoted the expression of CD54 and CD11b, and increased adhesion to extracellular matrix (ECM) proteins. In particular CD137-induced adhesion of THP-1 cells was inhibited by an inhibitor of mitogen-activated protein kinase kinase (MEK), but not by a p38 kinase inhibitor. Taken together, these results show that the adhesion and cytokine production of THP-1 cells induced by CD137 occur via activation of MEK, which results in the activation of ERK-1/2 signaling pathways. Therefore, this study suggests that CD137 induces an activating and migrating signal during inflammatory processes.
Antigens, CD/biosynthesis/*immunology ; Antigens, CD11/biosynthesis ; *Cell Adhesion ; Cell Adhesion Molecules/biosynthesis ; Cell Line ; Cytokines/*biosynthesis ; Enzyme Activation ; Extracellular Matrix Proteins/metabolism ; Flow Cytometry ; Humans ; Immunity, Natural ; Intercellular Adhesion Molecule-1/biosynthesis ; Interleukin-8/biosynthesis ; Mitogen-Activated Protein Kinase 1/metabolism ; Mitogen-Activated Protein Kinase 3/metabolism ; Mitogen-Activated Protein Kinase Kinases/antagonists & inhibitors/metabolism ; Monocytes/metabolism/*physiology ; Phosphorylation ; Protein Binding ; Receptors, Nerve Growth Factor/biosynthesis/*immunology ; Receptors, Tumor Necrosis Factor/biosynthesis/*immunology ; Research Support, Non-U.S. Gov't ; Signal Transduction ; Tumor Necrosis Factor-alpha/biosynthesis ; p38 Mitogen-Activated Protein Kinases/antagonists & inhibitors

Intimal hyperplasia is defined as the abnormal migration and proliferation of vascular smooth muscle cells (VSMCs) with deposition of extracellular matrix. However, the cell cycle regulatory mechanisms of injury-induced VSMC proliferation are largely unknown. To examine the expression kinetics of cell cycle regulatory factors which is known to be worked positively or negatively, we used rat balloon injury model. Marked induction of proliferating cell nuclear antigen (PCNA), G1/S cyclin-dependent kinase (cdk2), and its regulatory subunit (cyclin E) occurred between 1 and 3 days after balloon arterial injury, and this was sustained for up to 7 days and then declined. However, the induction of the negative regulators, p21 and p27, occurred between 3 and 5 days of injury, peaked after 7 and 14 days and was then sustained. VSMC proliferation after balloon catheter injury of the rat iliac artery is associated with coordinated expression of positive (cdk2, cyclin E and PCNA) and negative (p21, p27) regulators. Cell cycle regulators such as cdk2, cyclin E, p21, p27 may be suitable targets for the control of intimal hyperplasia.
Animals ; Arteries/*pathology ; Balloon Dilatation/*adverse effects ; Blotting, Western ; CDC2-CDC28 Kinases/biosynthesis ; Cell Cycle ; Cell Cycle Proteins/biosynthesis ; Cell Division ; Cyclin E/biosynthesis ; Cyclins/biosynthesis ; Endothelium, Vascular/pathology ; Extracellular Matrix/metabolism ; Hyperplasia/pathology ; Iliac Artery/pathology ; Immunohistochemistry ; Male ; Myocytes, Smooth Muscle/*cytology ; Proliferating Cell Nuclear Antigen/biosynthesis ; Rats ; Rats, Sprague-Dawley ; Support, Non-U.S. Gov't ; Time Factors ; Tumor Suppressor Proteins/biosynthesis