Comparative profile of exosomal microRNAs in postmenopausal women with various bone mineral densities by small RNA sequencing

To explore the role of plasma miRNAs in exosomes in early postmenopausal women. Small RNA sequencing was implemented to clarify the expression of miRNA in plasma exosomes obtained from 15 postmenopausal women, divided into groups of osteoporosis, osteopenia, and normal bone mass based on bone mineral density. Differentially expressed miRNAs (DEMs) were identified by comparing miRNA expression profiles. Five putative miRNAs, miR-224-3p, miR-25-5p, miR-302a-3p, miR-642a-3p, and miR-766-5p were confirmed by real-time PCR; miRNA target genes were obtained from 4 databases: miRWalk, miRDB, RNA22, and TargetScan. The miRNA-mRNA- Kyoto Encyclopedia of Genes and Genomes (KEGG) networks were analyzed, and the DEMs' potential role was investigated by gene ontology terms and KEGG pathway annotation. The results suggest that characterizing plasma exosomal miRNA profiles of early postmenopausal women by small RNA sequencing could identify novel exo-miRNAs involved in bone remodeling, and miR-642a-3p maybe contribute to the prediction and diagnosis of early postmenopausal osteoporosis.     

Expression profiling of mammalian microRNAs uncovers a subset of brain-expressed microRNAs with possible roles in murine and human neuronal differentiation

Background  

The microRNAs (miRNAs) are an extensive class of small noncoding RNAs (18 to 25 nucleotides) with probable roles in the regulation of gene expression. In Caenorhabditis elegans, lin-4 and let-7 miRNAs control the timing of fate specification of neuronal and hypodermal cells during larval development. lin-4, let-7 and other miRNA genes are conserved in mammals, and their potential functions in mammalian development are under active study.     

Management of bone health in postmenopausal women

Osteoporosis is a major public health problem. We now have an approach to case finding that involves the measurement of bone mineral density in people at high risk of fractures. The management of the individual includes the identification of risk factors, the choice of optimal therapy and the encouragement of long-term adherence with the planned treatment. The drugs that are available for the prevention of fractures are classed as anticatabolic or anabolic. The efficacy of these agents can be evaluated in the individual by monitoring changes in bone mineral density or bone turnover markers.     

Expression of exosomal microRNAs during chondrogenic differentiation of human bone mesenchymal stem cells

The aim of the current study was to compare the expression of microRNAs (miRNAs) in exosomes derived from human bone mesenchymal stem cells (hBMSCs) with and without chondrogenic induction. Exosomes derived from hBMSCs were isolated and identified. Microarray analysis was performed to compare miRNA expression between exosomes derived from hBMSCs with and without chondrogenic induction, and quantitative real-time polymerase chain reaction (qRT-PCR) was used to verify the differentially expressed miRNAs. hBMSCs were transfected with miRNA mimic to extract miRNA-overexpressed exosomes. The results showed that most exosomes exhibited a cup-shaped or round-shaped morphology with a diameter of approximately 50-200 nm and expressed CD9 and CD63. We detected 141 miRNAs that were differentially expressed with and without chondrogenic induction by over a twofold change, including 35 upregulated miRNAs, such as miR-1246, miR-1290, miR-193a-5p, miR-320c, and miR-92a, and 106 downregulated miRNAs, such as miR-377-3p and miR-6891-5p. qRT-PCR analysis validated these results. Exosomes derived from hBMSCs overexpressing miR-320c were more efficient than normal exosomes derived from control hBMSCs at promoting osteoarthritis chondrocyte proliferation, down-regulated matrix metallopeptidase 13 and up-regulated (sex determining region Y)-box 9 expression during hBMSC chondrogenic differentiation. In conclusion, we identified a group of upregulated miRNAs in exosomes derived from hBMSCs with chondrogenic induction that may play an important role in mesenchymal stem cell-derived exosomes in cartilage regeneration and, ultimately, the treatment of arthritis. We demonstrated the potential of these modified exosomes in the development of novel therapeutic strategies.     

Glycomic profiling of carcinoembryonic antigen isolated from human tumor tissue

Background

Carcinoembryonic antigen (CEA) is a protein commonly found in human serum, with elevated CEA levels being linked to the progression of a wide range of tumors. It is currently used as a biomarker for malign tumors such as lung cancer and colorectal cancer [Urol Oncol: Semin Orig Invest 352: 644–648, 2013 and Lung Cancer 80: 45-49, 2013]. However, due to its low specificity in clinical applications, CEA can be used for monitoring only, rather than tumor diagnosis. The function of many glycoproteins is critically dependent on their glycosylation pattern, which in turn has the potential to serve in tumor detection. However, little is known about the detailed glycan patterns of CEA.

Methods

To determine these patterns, we isolated and purified CEA proteins from human tumor tissues using immunoaffinity chromatography. The glycan patterns of CEA were then analyzed using a Matrix-Assisted Laser Desorption/Ionization-Time of Flight-Mass Spectrometry³ (MALDI-TOF-MS³) approach.

Results

We identified 61 glycoforms in tumor tissue, where CEA is upregulated. These glycosylation entities were identified as bi-antennary, tri-antennary and tetra-antennary structures carrying sialic acid and fucose residues, and include a multitude of glycans previously not reported for CEA.

Conclusion

Our findings should facilitate a more precise tumor prediction than currently possible, ultimately resulting in improved tumor diagnosis and treatment.

Electronic supplementary material

The online version of this article (doi:10.1186/s12014-015-9088-3) contains supplementary material, which is available to authorized users.     

Expression profiling of human glial precursors

Background  

We have generated gene expression databases for human glial precursors, neuronal precursors, astrocyte precursors and neural stem cells and focused on comparing the profile of glial precursors with that of other populations.     

Target labelling for the detection and profiling of microRNAs expressed in CNS tissue using microarrays

Background  

MicroRNAs (miRNA) are a novel class of small, non-coding, gene regulatory RNA molecules that have diverse roles in a variety of eukaryotic biological processes. High-throughput detection and differential expression analysis of these molecules, by microarray technology, may contribute to a greater understanding of the many biological events regulated by these molecules. In this investigation we compared two different methodologies for the preparation of labelled miRNAs from mouse CNS tissue for microarray analysis. Labelled miRNAs were prepared either by a procedure involving linear amplification of miRNAs (labelled-aRNA) or using a direct labelling strategy (labelled-cDNA) and analysed using a custom miRNA microarray platform. Our aim was to develop a rapid, sensitive methodology to profile miRNAs that could be adapted for use on limited amounts of tissue.     

The relationship between bone marrow adipose tissue and bone metabolism in postmenopausal osteoporosis

Postmenopausal osteoporosis (PMOP) is a prevalent skeletal disorder associated with menopause-related estrogen withdrawal. PMOP is characterized by low bone mass, deterioration of the skeletal microarchitecture, and subsequent increased susceptibility to fragility fractures, thus contributing to disability and mortality. Accumulating evidence indicates that abnormal expansion of marrow adipose tissue (MAT) plays a crucial role in the onset and progression of PMOP, in part because both bone marrow adipocytes and osteoblasts share a common ancestor lineage. The cohabitation of MAT adipocytes, mesenchymal stromal cells, hematopoietic cells, osteoblasts and osteoclasts in the bone marrow creates a microenvironment that permits adipocytes to act directly on other cell types in the marrow. Furthermore, MAT, which is recognized as an endocrine organ, regulates bone remodeling through the secretion of adipokines and cytokines. Although an enhanced MAT volume is linked to low bone mass and fractures in PMOP, the detailed interactions between MAT and bone metabolism remain largely unknown. In this review, we examine the possible mechanisms of MAT expansion under estrogen withdrawal and further summarize emerging findings regarding the pathological roles of MAT in bone remodeling. We also discuss the current therapies targeting MAT in osteoporosis. A comprehensive understanding of the relationship between MAT expansion and bone metabolism in estrogen deficiency conditions will provide new insights into potential therapeutic targets for PMOP.     

Aromatase in synovial cells from postmenopausal women

Peripheral aromatization of androgens exerts estrogenic actions in many tissues. In this study, osteoarthritis synoviocytes were examined to clarify the possible action of adrenal androgen on synovial cell. Synoviocytes from postmenopausal women are able to express aromatase mRNA. By sequence analysis, the PCR fragment (485 bp) was determined to be 100% identical to that of human placental aromatase cDNA. Moreover, this study demonstrates that adrenal androgen, androstenedione, is converted to estrone (E(1)) and estradiol (E(2)) in synoviocytes by aromatase which is positively regulated by glucocorticoids such as dexamethasone. E(2) production reduced significantly IL-6 secretion. These data provide preliminary evidence that in situ estrogen production by synoviocytes may have a role in OA susceptibility. However the role of E(2) in OA is not clear and remains to be determined.     

Serum lipid levels and bone mineral density in Greek postmenopausal women

Contradictory results have been reported regarding a relationship between serum lipid levels and bone mineral density. The purpose of this study was to further investigate a possible relationship between those parameters in Greek postmenopausal women. A total of 591 patients followed at a tertiary hospital were examined for seven different lipid factors in relation to dual-emission X-ray absorptiometry measurements at the lumbar spine. Lipoprotein-a was the only lipid measurement that univariately showed an almost significant trend of association with bone mass category (analysis of variance [ANOVA] p value 0.062 for Ln(Lipoprotein-a)). In multiple regression, it was noted that a non-significant negative trend of association of high density lipoprotein (HDL) cholesterol and Apolipoprotein AI with lumbar T-score (p value 0.058 and 0.075, respectively). In age subgroup analysis, Lipoprotein-a and Ln(Lipoprotein-a) presented a negative correlation with lumbar T-score for women with age ≥ 53 years (p value 0.043 and 0.070, respectively), while a negative correlation of HDL and Apolipoprotein AI levels with lumbar T-score remained in women with age < 53 years (p value 0.039 and 0.052, respectively). The findings do not support a strong relationship between lipid levels and bone mass measurements.     

A left/right comparison of sequential bone loss from the metacarpals of postmenopausal women

The rate of decrease of mean metacarpal cortical width was assessed by sequential radiographic morphometry for each hand separately in a series of 46 right-handed postmenopausal women observed for 222 patient-years. For the left hand, the mean rate was 0.0331 ± 0.0053 mm/year and for the right, 0.0310 ± 0.0060 mm/year. The difference between the hands in the rate of decrease was not significant. It is concluded that the higher work load of the dominant hand has no effect on the rate of bone loss from the metacarpals of postmenopausal women.     

Influence of bone mineral density in circulating adipokines among postmenopausal Arab women

Osteoporosis and osteopenia has a significant link with substantial fracture risk. Epidemiological data revealed a protective role of adipose tissue on bone biology in postmenopausal osteoporosis. The current study assessed the associations between select adipokines and bone mineral density (BMD) in postmenopausal women. A total of 175 Saudi postmenopausal women were selected and categorized based on their BMD (normal & low-BMD). Circulating levels of select adipokines (adiponectin, resistin, leptin, and adipsin), insulin, 25(OH)D and RANKl were determined using commercially available assay kits. BMD was measured by dual-energy X-ray absorptiometry (DXA). Overall and among low-BMD subjects, adiponectin consistently showed a significant inverse association with BMD (overall −0.34, p < 0.01; low BMD group −0.34, p < 0.01). In multiple regression, adiponectin (−0.29 ± 0.06, p < 0.00) and resistin (−0.08 ± 0.04, p < 0.05) were inversely significant with BMD overall, but after stratification the significance was lost for resistin (−0.05 ± 0.04, p < 0.224) whereas adiponectin remained (−0.22 ± 0.07, p < 0.02) in low-BMD subjects. Adipsin, leptin and lipocalin-2 showed no significant associations. Findings of the present study revealed that only adiponectin showed a significantly strong inverse association with low BMD, suggesting that insulin sensitivity may influence bone health in Arab postmenopausal women.     

Cloning and expression profiling of testis-expressed microRNAs

Using a new small RNA cloning method, we identified 141 miRNAs from the mouse testis, of which 29 were novel. The 141 miRNAs were mapped onto all chromosomes except the Y chromosome and 2/3 of these miRNA genes exist as clusters. ∼ 70% of these miRNA genes were located in intronic or intergenic regions, whereas the remaining miRNAs were derived from exonic sequences. We further validated these cloned miRNAs by examining their expression in multiple mouse organs including developing testes and also in purified spermatogenic cells using semi-quantitative PCR analyses. Our expression profiling assays revealed that 60% of the testis-expressed miRNAs were ubiquitously expressed and the remaining are either preferentially (35%) or exclusively (5%) expressed in the testis. We also observed a lack of strand selection during testicular miRNA biogenesis, characterized by paired expression of both the 5′ strands and 3′ strands derived from the same precursor miRNAs. The present work identified numerous miRNAs preferentially or exclusively expressed in the testis, which would be interesting targets for further functional studies.