Bone microRNAs and Ageing Kranjc, Tilen; Ostanek, Barbara; Marc, Janja
Current pharmaceutical biotechnology,
03/2017, Volume:
18, Issue:
3
Journal Article
Peer reviewed
The decline of tissue function in ageing is a consequence of many changes in the gene expression and other extrinsic factors. The molecular mechanisms underlying these changes are heavily ...investigated with focus on regulation of time-lapse gene expression. microRNAs, short non-coding RNA molecules, are among the major regulators of gene expression. microRNAs have been shown to control ageing-related mechanisms and several evidences suggest age-related changes in microRNA transcriptome. However, the source regulator of time-lapse gene expression control still remains unknown. Here, we have reviewed microRNA molecules related to the ageing of bones and studies that investigated age-related bone tissue gene expression. We identified 41 microRNA molecules from the literature that correlate with bone mineral density or fractures and one recent study has demonstrated how a combination of several microRNAs can be used for better prediction of the fractures in osteoporotic patients. The personalised diagnostic algorithms in the future should be therefore based on the combination of multiple biomarkers. Until now, little is known about the regulatory mechanisms of microRNA expression and genes in ageing. We have proposed a link between telomere length and gene expression profiles, however this now needs to be further investigated.
RT-qPCR is the gold standard and the most commonly used method for measuring gene expression. Selection of appropriate reference gene(s) for normalization is a crucial part of RT-qPCR experimental ...design, which allows accurate quantification and reliability of the results. Because there is no universal reference gene and even commonly used housekeeping genes' expression can vary under certain conditions, careful selection of an appropriate internal control must be performed for each cell type or tissue and experimental design. The aim of this study was to identify the most stable reference genes during osteogenic differentiation of the human osteosarcoma cell lines MG-63, HOS, and SaOS-2 using the geNorm, NormFinder, and BestKeeper statistical algorithms. Our results show that
,
,
, and
are the most stably expressed genes, while
, and
expressions are most variable. These data provide a basis for future RT-qPCR normalizations when studying gene expression during osteogenic differentiation, for example, in studies of osteoporosis and other bone diseases.
Osteoporosis is a metabolic bone disease that mostly affects the elderly. A lot of drugs are available, mostly with an antiresorptive effect but just a few with an osteoanabolic effect, meaning they ...promote bone building. PTH (1-34) or teriparatide is an osteoanabolic drug, but its efficacy varies between individuals. We performed a literature review and extracted a dataset of 62 microRNAs (miRNAs) from 10 different studies; predicted miRNA target interactions (MTIs) were obtained with the help of four software tools: DIANA, miRWalk, miRDB and TargetScan. With the construction of an interactome of PTH-regulated miRNAs and their predicted target genes, we elucidated miR-146a-5p, miR-551b-5p, miR-205-3p, miR-33a-3p, miR-338-5p as miRNAs with the most interactions and miR-410-3p as the miRNA targeting bone-related pathways with the highest significance. These miRNAs could help in further understanding the mechanism of action of PTH on bone metabolism and osteoporosis. They also have the potential for novel network-based biomarkers for osteoporosis treatment efficacy and safety and as new therapeutic targets.
In the present study, we examined redox status parameters in arterial and venous blood samples, its potential to predict the prognosis of acute myocardial infarction (AMI) patients assessed through ...its impact on the comprehensive grading SYNTAX score, and its clinical accuracy. Potential connections between common blood biomarkers, biomarkers of redox status, leukocyte telomere length, and telomerase enzyme activity in the acute myocardial infarction burden were assessed using principal component analysis (PCA). This study included 92 patients with acute myocardial infarction. Significantly higher levels of advanced oxidation protein products (AOPP), superoxide anion (O2•−), ischemia-modified albumin (IMA), and significantly lower levels of total oxidant status (TOS) and total protein sulfhydryl (SH-) groups were found in arterial blood than in the peripheral venous blood samples, while biomarkers of the telomere–telomerase system did not show statistical significance in the two compared sample types (p = 0.834 and p = 0.419). To better understand the effect of the examined biomarkers in the AMI patients on SYNTAX score, those biomarkers were grouped using PCA, which merged them into the four the most contributing factors. The “cholesterol–protein factor” and “oxidative–telomere factor” were independent predictors of higher SYNTAX score (OR = 0.338, p = 0.008 and OR = 0.427, p = 0.035, respectively), while the ability to discriminate STEMI from non-STEMI patients had only the “oxidative–telomere factor” (AUC = 0.860, p = 0.008). The results show that traditional cardiovascular risk factors, i.e., high total cholesterol together with high total serum proteins and haemoglobin, are associated with severe disease progression in much the same way as a combination of redox biomarkers (pro-oxidant-antioxidant balance, total antioxidant status, IMA) and telomere length.
Summary
Background
Osteoporosis is a prevalent skeletal disorder characterized by reduced bone mineral density and microarchitectural deterioration of bone tissue, resulting in bone fragility and ...low-trauma fractures. Imaging techniques are routinely used to detect low bone mass; however, they are unable to identify deterioration of bone quality. Recently, microRNAs have emerged as regulators of bone remodelling and potentially also as a new class of sensitive biomarkers of bone health to aid in diagnosis and treatment monitoring of osteoporosis.
Methods
To identify new plasma-based biomarkers associated with osteoporosis we analyzed microRNAs isolated from plasma samples of 74 postmenopausal women divided into osteoporotic (
N =
17) and control groups (
N =
57). A prior microRNA screening was performed where a few showed promise for further analysis. Quantitative polymerase chain reaction was used to investigate differences in expression of let-7d-5p, let-7e-5p, miR-30d-5p, miR-30e-5p, miR-126-3p, miR-148a-3p, miR-199a-3p, miR-423-5p and miR-574-5p between the two groups. Furthermore, correlation analysis between microRNA expression levels and patient bone mineral density measurements and fracture risk assessment tool (FRAX) as well as trabecular bone scores were performed.
Results
Expression of miR-148a-3p was significantly higher (
p
= 0.042) in the osteoporotic patient group compared to the controls. In addition, we identified correlations between miR-126-3p (ρ = 0.253,
p
= 0.032) and 423-5p (ρ = −0.230,
p
= 0.049) and parameters of bone quality and quantity.
Conclusion
The results from our study, together with the functional role of miR-148a-3p in bone suggest that this microRNA could be considered as a potential new plasma-based biomarker for pathological changes associated with osteoporosis.
Cathepsin K and MMP-9 are considered to be the most abundant proteases in osteoclasts. TRAP is a marker for osteoclasts, and there is increasing evidence of its proteolytic role in bone resorption. ...RANKL is a recently discovered regulator of osteoclast maturation and activity and induces expression of many genes. This study compared cathepsin K, MMP-9, TRAP, RANKL, OPG, and osteocalcin gene expression in the proximal femur of patients with osteoarthritis with that of patients with femoral neck fracture. Fifty-six patients undergoing arthroplasty because of osteoarthritis or femoral neck fracture were included in the study. Total mRNA was extracted from the bone samples obtained from the intertrochanteric region of the proximal femur. Real-time RT-PCR was used to quantify CTSK (cathepsin K), MMP-9 (matrix metalloproteinase 9), ACP5 (TRAP), TNFSF11 (RANKL), TNFRSF11B (OPG), and BGLAP (osteocalcin) mRNAs. The levels of mRNAs coding for MMP-9 and osteocalcin indicated higher expression in the osteoarthritic group (P = 0.011, P = 0.001, respectively), whereas RANKL expression and the ratio RANKL/OPG were both significantly lower in the osteoarthritic group than in the fracture group. Expression of cathepsin K, MMP-9, and TRAP relative to RANKL was significantly higher in the osteoarthritic group. Ratios of all three proteolytic enzymes relative to formation marker osteocalcin were higher in the fracture group. Gene expression of cathepsin K, MMP-9, TRAP, RANKL, OPG, and osteocalcin and the association between their mRNA levels pointed to higher bone resorption and bone formation in osteoarthritis, differences in balance between them, and differences in regulation of bone resorption in osteoarthritic and osteoporotic bone.
Telomeres are protective chromosomal ends. Short telomeres are a proven biomarker of biological aging. We aimed to find an association of telomere length and telomerase activity in circulating ...leukocytes and thromboaspirates of patients with acute myocardial infarction. Furthermore, association of the telomere-telomerase system with oxidative stress markers (as common risk factors for coronary artery disease (CAD)) was tested.
Patients were selected from the patients admitted to the intensive care unit with acute myocardial infarction with ST-segment elevation (STEMI), with the following inclusion criteria - STEMI patients between 18 and 80 years old of both genders and candidates for primary percutaneous coronary intervention, with infarction pain present for a maximum of 12 h. In all the patients leukocyte telomere length, telomerase activity and scores related to oxidative-stress status (Protective, Damage and OXY) were evaluated.
Patients were divided into different groups: with stable angina pectoris (AP) (
= 22), acute myocardial infarction with: STEMI (
= 93), non-obstructive coronary arteries (MINOCA) (
= 7), blood vessel rupture (
= 6) at three time points, and compared to the group of 84 healthy subjects. Telomerase activity was significantly higher in all CAD sub-groups compared to the control group (AP = 0.373 (0.355-0.386), STEMI = 0.375 (0.349-0.395), MINOCA = 0.391 (0.366-0.401), blood vessel rupture = 0.360 (0.352-0.385) vs. CG = 0.069 (0.061-0.081),
< 0.001), while telomeres were significantly shorter in STEMI, MINOCA and blood vessel rupture groups compared to the control group (STEMI = 1.179 (0.931-1.376), MINOCA = 1.026 (0.951-1.070), blood vessel rupture = 1.089 (0.842-1.173) vs. CG = 1.329 (1.096-1.624),
= 0.030. Values of OXY score were significantly higher in STEMI and MINOCA patients compared to the control group and AP patients (5.83 (4.55-7.54) and 10.28 (9.19-10.72) vs. 4.94 (3.29-6.18) and 4.18 (2.58-4.86),
< 0.001). Longer telomeres and higher telomerase activity were found in thromboaspirates, compared to the peripheral blood leukocytes in the same patients (1.25 (1.01-1.84) vs. 1.18 (0.909-1.516),
= 0.036; and 0.366 (0.367-0.379) vs. 0.366 (0.367-0.379),
< 0.001, respectively). In addition, telomere length and telomerase activity had good diagnostic ability to separate STEMI patients from healthy persons.
Leukocyte telomere length and telomerase activity can differentiate CAD patients from healthy persons, and relate CAD to oxidative stress.
The availability of large human datasets for genome-wide association studies (GWAS) and the advancement of sequencing technologies have boosted the identification of genetic variants in complex and ...rare diseases in the skeletal field. Yet, interpreting results from human association studies remains a challenge. To bridge the gap between genetic association and causality, a systematic functional investigation is necessary. Multiple unknowns exist for putative causal genes, including cellular localization of the molecular function. Intermediate traits ("endophenotypes"), e.g. molecular quantitative trait loci (molQTLs), are needed to identify mechanisms of underlying associations. Furthermore, index variants often reside in non-coding regions of the genome, therefore challenging for interpretation. Knowledge of non-coding variance (e.g. ncRNAs), repetitive sequences, and regulatory interactions between enhancers and their target genes is central for understanding causal genes in skeletal conditions. Animal models with deep skeletal phenotyping and cell culture models have already facilitated fine mapping of some association signals, elucidated gene mechanisms, and revealed disease-relevant biology. However, to accelerate research towards bridging the current gap between association and causality in skeletal diseases, alternative
platforms need to be used and developed in parallel with the current -omics and traditional
resources. Therefore, we argue that as a field we need to establish resource-sharing standards to collectively address complex research questions. These standards will promote data integration from various -omics technologies and functional dissection of human complex traits. In this mission statement, we review the current available resources and as a group propose a consensus to facilitate resource sharing using existing and future resources. Such coordination efforts will maximize the acquisition of knowledge from different approaches and thus reduce redundancy and duplication of resources. These measures will help to understand the pathogenesis of osteoporosis and other skeletal diseases towards defining new and more efficient therapeutic targets.
Ustekinumab is a monoclonal antibody used in Crohn’s disease (CD). Dose optimization in case of non-response and the role of pharmacokinetic–pharmacodynamic (PK-PD) monitoring remain unresolved ...dilemmas in clinical practice. We aimed to develop a population PK-PD model for ustekinumab in CD and simulate efficacy of alternative dosing regimens. We included 57 patients and recorded their characteristics during 32 weeks after starting with ustekinumab therapy. Serum ustekinumab concentration was prospectively measured and fecal calprotectin (FC) concentration was used to monitor the disease activity. Ustekinumab PK-PD was described by a two-compartment target-mediated drug disposition model linked to an indirect response model. Lower fat-free mass, higher serum albumin, previous non-exposure to biologics, FCGR3A-158 V/V variant and lower C-reactive protein were associated with higher ustekinumab exposure. Model-based simulation suggested that 41.9% of patients receiving standard dosing achieve biochemical remission at week 32. In patients not achieving remission with standard dosing at week 16, transition to 4-weekly subcutaneous maintenance dosing with or without intravenous reinduction resulted in comparably higher remission rates at week 32 (51.1% vs. 49.2%, respectively). Our findings could be used to guide stratified ustekinumab treatment in CD, particularly in patients with unfavorable characteristics, who might benefit from early transition to 4-weekly maintenance dosing.
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