MicroRNAs, epigenetics and disease

MicroRNA-29a: a novel target for non-operative management of symptomatic lumbar spinal stenosis

PURPOSE

Lumbar spinal stenosis (LSS) is the most common reason for spinal surgery in patients over the age of 65, and there are few effective non-surgical treatments. Therefore, the development of novel treatment or preventative modalities to decrease overall cost and morbidity associated with LSS is an urgent matter. The cause of LSS is multifactorial; however, a significant contributor is ligamentum flavum hypertrophy (LFH) which causes mechanical compression of the cauda equina or nerve roots. We assessed the role of a novel target, microRNA-29a (miR-29a), in LFH and investigated the potential for using miR-29a as a therapeutic means to combat LSS.

METHODS

Ligamentum flavum (LF) tissue was collected from patients undergoing decompressive surgery for LSS and assessed for levels of miR-29a and pro-fibrotic protein expression. LF cell cultures were then transfected with either miR-29a over-expressor (agonist) or inhibitor (antagonist). The effects of over-expression and under-expression of miR-29a on expression of pro-fibrotic proteins was assessed.

RESULTS

We demonstrated that LF at stenotic levels had a loss of miR-29a expression. This was associated with greater LF tissue thickness and higher mRNA levels of collagen I and III. We also demonstrated that miR29-a plays a direct role in the regulation of collagen gene expression in ligamentum flavum. Specifically, agents that increase miR-29a may attenuate LFH, while those that decrease miR-29a promote fibrosis and LFH.

CONCLUSION

This study demonstrates that miR-29a may potentially be used to treat LFH and provides groundwork to initiate the development of a therapeutic product for LSS.

MicroRNA-21 Silencing in Diabetic Nephropathy: Insights on Therapeutic Strategies

In diabetes, possibly the most significant site of microvascular damage is the kidney. Due to diabetes and/or other co-morbidities, such as hypertension and age-related nephron loss, a significant number of people with diabetes suffer from kidney diseases. Improved diabetic care can reduce the prevalence of diabetic nephropathy (DN); however, innovative treatment approaches are still required. MicroRNA-21 (miR-21) is one of the most studied multipotent microRNAs (miRNAs), and it has been linked to renal fibrosis and exhibits significantly altered expression in DN. Targeting miR-21 offers an advantage in DN. Currently, miR-21 is being pharmacologically silenced through various methods, all of which are in early development. In this review, we summarize the role of miR-21 in the molecular pathogenesis of DN and several therapeutic strategies to use miR-21 as a therapeutic target in DN. The existing experimental interventions offer a way to rectify the lower miRNA levels as well as to reduce the higher levels. Synthetic miRNAs also referred to as miR-mimics, can compensate for abnormally low miRNA levels. Furthermore, strategies like oligonucleotides can be used to alter the miRNA levels. It is reasonable to target miR-21 for improved results because it directly contributes to the pathological processes of kidney diseases, including DN.

Adolescent idiopathic scoliosis : a review of aetiological theories of a multifactorial disease

Adolescent idiopathic scoliosis (AIS), defined by an age at presentation of 11 to 18 years, has a prevalence of 0.47% and accounts for approximately 90% of all cases of idiopathic scoliosis. Despite decades of research, the exact aetiology of AIS remains unknown. It is becoming evident that it is the result of a complex interplay of genetic, internal, and environmental factors. It has been hypothesized that genetic variants act as the initial trigger that allow epigenetic factors to propagate AIS, which could also explain the wide phenotypic variation in the presentation of the disorder. A better understanding of the underlying aetiological mechanisms could help to establish the diagnosis earlier and allow a more accurate prediction of deformity progression. This, in turn, would prompt imaging and therapeutic intervention at the appropriate time, thereby achieving the best clinical outcome for this group of patients. Cite this article: Bone Joint J 2022;104-B(8):915-921.

Immunomodulatory Properties of Human Breast Milk: MicroRNA Contents and Potential Epigenetic Effects

Infants who are exclusively breastfed in the first six months of age receive adequate nutrients, achieving optimal immune protection and growth. In addition to the known nutritional components of human breast milk (HBM), i.e., water, carbohydrates, fats and proteins, it is also a rich source of microRNAs, which impact epigenetic mechanisms. This comprehensive work presents an up-to-date overview of the immunomodulatory constituents of HBM, highlighting its content of circulating microRNAs. The epigenetic effects of HBM are discussed, especially those regulated by miRNAs. HBM contains more than 1400 microRNAs. The majority of these microRNAs originate from the lactating gland and are based on the remodeling of cells in the gland during breastfeeding. These miRNAs can affect epigenetic patterns by several mechanisms, including DNA methylation, histone modifications and RNA regulation, which could ultimately result in alterations in gene expressions. Therefore, the unique microRNA profile of HBM, including exosomal microRNAs, is implicated in the regulation of the genes responsible for a variety of immunological and physiological functions, such as FTO, INS, IGF1, NRF2, GLUT1 and FOXP3 genes. Hence, studying the HBM miRNA composition is important for improving the nutritional approaches for pregnancy and infant's early life and preventing diseases that could occur in the future. Interestingly, the composition of miRNAs in HBM is affected by multiple factors, including diet, environmental and genetic factors.

Idiopathic scoliosis: general characteristics and analysis of etiological theories (literature review)

Idiopathic scoliosis is a severe pathology of the musculoskeletal system that affects children and adolescents all over the world. The disease occurs in approximately 0.2-0.6% of the general population, and is the largest subgroup of spinal curvature in humans (70-90% of all known scoliosis cases). In idiopathic scoliosis, a threedimensional deformation of the vertebral column is formed, leading to the formation of a rib hump, curvature of the ribs and chest, asymmetry of the pelvis and impaired development of internal organs. The main feature of the disease is the spontaneous development of deformity during the growth of the child and the tendency to progress. Scoliosis is not only an orthopedic disease, but also a ignificant cosmetic, and, consequently, a psychological and social problem. The standard of treatment for scoliotic disease remains unchanged for a long time: observation, corset treatment and surgical correction. The prognosis for the development of pathology varies depending on the degree of deformation. The corset-therapy, hospitalization, surgery and treatment of chronic back pain have a negative impact on the psychoemotional state of children and adolescents. Despite significant advances in the methods of diagnosis of deformity, improvement of surgical treatment methods and in the study of pathogenesis, the etiological factor of pathology is still unknown. The search for the causes of idiopathic scoliosis covers almost all aspects of its possible origin: genetic, environmental, hormonal, metabolic, biochemical, neurological, and others. In recent decades, relevant theories of the development of scoliosis have been formulated, but none of the theories reveals the essence of the pathological process and has no clear justification. The greatest number of supporters is the genetic theory: genetic factors play a key role in the occurrence and development of idiopathic scoliosis. Understanding the underlying factors of the disease will enable prevention, early diagnosis, and identification of the risk groups of the patients in question.

Dysregulation of MicroRNAs in Hypertrophy and Ossification of Ligamentum Flavum: New Advances, Challenges, and Potential Directions

Pathological changes in the ligamentum flavum (LF) can be defined as a process of chronic progressive aberrations in the nature and structure of ligamentous tissues characterized by increased thickness, reduced elasticity, local calcification, or aggravated ossification, which may cause severe myelopathy, radiculopathy, or both. Hypertrophy of ligamentum flavum (HLF) and ossification of ligamentum flavum (OLF) are clinically common entities. Though accumulated evidence has indicated both genetic and environmental factors could contribute to the initiation and progression of HLF/OLF, the definite pathogenesis remains fully unclear. MicroRNAs (miRNAs), one of the important epigenetic modifications, are short single-stranded RNA molecules that regulate protein-coding gene expression at posttranscriptional level, which can disclose the mechanism underlying diseases, identify valuable biomarkers, and explore potential therapeutic targets. Considering that miRNAs play a central role in regulating gene expression, we summarized current studies from the point of view of miRNA-related molecular regulation networks in HLF/OLF. Exploratory studies revealed a variety of miRNA expression profiles and identified a battery of upregulated and downregulated miRNAs in OLF/HLF patients through microarray datasets or transcriptome sequencing. Experimental studies validated the roles of specific miRNAs (e.g., miR-132-3p, miR-199b-5p in OLF, miR-155, and miR-21 in HLF) in regulating fibrosis or osteogenesis differentiation of LF cells and related target genes or molecular signaling pathways. Finally, we discussed the perspectives and challenges of miRNA-based molecular mechanism, diagnostic biomarkers, and therapeutic targets of HLF/OLF.

Developmental Dioxin Exposure Alters the Methylome of Adult Male Zebrafish Gonads

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a persistent environmental toxicant and endocrine disrupting compound with reproductive and developmental effects in humans and model organisms, including zebrafish. Our previous microarray and histological studies found defects in spermatogenesis and fertility of zebrafish in response to acute developmental TCDD exposure. These effects are apparent following exposure during reproductive development, modeling fetal basis of adult-onset disease. Some outcomes of these previous studies (reduced fertility, changes in sex ratio, transcriptomic alterations) are also transgenerational – persisting to unexposed generations – through the male germline. We hypothesized that DNA methylation could be a possible mechanism for these reproductive effects and performed whole genome bisulfite sequencing (WGBS), which identifies whole genome DNA methylation status at the base pair level, on testes of adult zebrafish exposed to TCDD (two separate hour-long exposures to 50 pg/mL TCDD at 3 and 7 weeks post fertilization). In response to TCDD exposure, multiple genes were differentially methylated; many of which are involved in reproductive processes or epigenetic modifications, suggesting a role of DNA methylation in later-life health outcomes. Additionally, several differentially methylated genes corresponded with gene expression changes identified in TCDD-exposed zebrafish testes, indicating a potential link between DNA methylation and gene expression. Ingenuity pathway analysis of WGBS and microarray data revealed genes involved in reproductive processes and development, RNA regulation, the cell cycle, and cellular morphology and development. We conclude that site-specific changes in DNA methylation of adult zebrafish testes occur in response to acute developmental TCDD exposure.

Hippo signaling pathway is altered in Duchenne muscular dystrophy

Hippo signaling pathway is considered a key regulator of tissue homeostasis, cell proliferation, apoptosis and it is involved in cancer development. In skeletal muscle, YAP, a downstream target of the Hippo pathway, is an important player in myoblast proliferation, atrophy/hypertrophy regulation, and in mechano-trasduction, transferring mechanical signals into transcriptional responses. We studied components of Hippo pathway in muscle specimens from patients with Duchenne muscular dystrophy (DMD), Becker muscular dystrophy, limb-girdle muscular dystrophy type 2A and type 2B and healthy subjects. Only DMD muscles had decreased YAP1 protein expression, increased LATS1/2 kinase activity, low Survivin mRNA expression and high miR-21 expression. In light of our novel results, a schematic model is postulated: low levels of YOD1 caused by increased inhibition by miR-21 lead to an increase of LATS1/2 activity which in turn augments phosphorylation of YAP. Reduced amount of active YAP, which is also a target of increased miR-21, causes decreased nuclear expression of YAP-mediated target genes. Since it is known that YAP has beneficial roles in promoting tissue repair and regeneration after injury so that its activation may be therapeutically useful, our results suggest that some components of Hippo pathway could become novel therapeutic targets for DMD treatment.

Down-regulated serum microRNA-101 is associated with aggressive progression and poor prognosis of cervical cancer

Objective

MicroRNAs (miRNAs) play a vital role in pathogenesis and progression of many cancers, including cervical cancer. However, importance of serum level of miR-101 in cervical cancer has rarely been studied. In the present study, clinical significance and prognostic value of serum miR-101 for cervical cancer was investigated.

Methods

Association between miR-101 level in cervical cancer tissues and prognosis of patients was analyzed by using data retrieved from The Cancer Genome Atlas (TCGA) database, which was followed with our clinical study in which miR-101 serum level comparison between cervical cancer patients and healthy controls was conducted by real-time quantitative polymerase chain reaction (PCR).

Results

TCGA database demonstrated that miR-101 was down-regulated in cervical cancer tissues compared with normal cervical tissues, and univariate Cox regression analysis indicated that decreased miR-101 expression was a highly significant negative risk factor. Similar trend was found in the serum miR-101. Serum level of miR-101 was associated with International Federation of Gynecology and Obstetrics (FIGO) stage (p=0.003), lymph node metastasis (p=0.001), and serum squamous cell carcinoma antigen (SCC-Ag) level >4 (p=0.007). The overall survival time of cervical cancer patients with a higher level of serum miR-101 was significantly longer than that of patients with a lower level of serum miR-101. Moreover, multivariate Cox regression analysis indicated that the down-regulated serum level of miR-101 was an independent predictor for the unfavorable prognosis of cervical cancer.

Conclusion

Serum level of miR-101 is closely associated with metastasis and prognosis of cervical cancer; and, hence could be a potential biomarker and prognostic predictor for cervical cancer.

Etiological Theories of Adolescent Idiopathic Scoliosis: Past and Present

Adolescent idiopathic scoliosis is one of the most common spinal deformities, yet its cause is unknown. Various theories look to biomechanical, neuromuscular, genetic, and environmental origins, yet our understanding of scoliosis etiology is still limited. Determining the cause of a disease is crucial to developing the most effective treatment. Associations made with scoliosis do not necessarily point to causality, and it is difficult to determine whether said associations are primary (playing a role in development) or secondary (develop as a result of scoliosis). Scoliosis is a complex condition with highly variable expression, even among family members, and likely has many causes. These causes could be similar among homogenous groups of AIS patients, or they could be individual. Here, we review the most prevalent theories of scoliosis etiology and recent trends in research.

miR-21 inhibition of LATS1 promotes proliferation and metastasis of renal cancer cells and tumor stem cell phenotype

MicroRNA (miR)-21 has many regulatory functions in the cell, including activities in cancer cells and cancer stem cells. Large tumor suppressor gene 1 (LATS1) is a target of miR-21 that could mediate several of these phenotypes. This study explored the effect of miR-21 silencing in renal cancer cell function and LATS1 expression. Silencing of miR-21 in Caki-2 cells reached an efficiency of 55-60%. This was sufficient to detect decrease in Caki-2 cell proliferation and migration invasion capacity. miR-21 silencing increased LATS1 expression at both mRNA and protein levels. The number of tumor spheres formed by cells expressing si-miR-21 was significantly reduced and the expression of tumor stem cell markers Nanog and CT3/4 were significantly downregulated. miR-21 seems to regulate LATS1 expression in renal cancer Caki-2 cells, resulting in reduced proliferation, invasion, and cancer stem cell phenotype. miR-21 may promote malignant phenotype of tumor cells through LATS1 silencing, which can be regarded as a new target candidate gene for renal cancer treatment.

MicroRNA promoter methylation: a new tool for accurate detection of urothelial carcinoma

Background:

Urothelial carcinoma (UC) is the most common cancer affecting the urinary system, worldwide. Lack of accurate early detection tools entails delayed diagnosis, precluding more efficient and timely treatment. In a previous study, we found that miR-129-2 and miR-663a were differentially methylated in UC compared with other genitourinary tract malignancies. Here, we evaluated the diagnostic performance of those microRNAs in urine.

Methods:

Promoter methylation levels of miR-129-2 and miR-663a were assessed, using real-time quantitative methylation-specific PCR, in UC tissue samples (using normal urothelium as control) and, subsequently, in urine samples from UC and other genitourinary malignancies. Diagnostic and prognostic performances were evaluated by receiver operator characteristics curve and survival analyses, respectively.

Results:

Promoter methylation levels of both microRNAs were significantly higher in UC tissue samples compared with normal urothelium. In urine, the assay was able to distinguish UC from other genitourinary tract carcinomas with 87.7% sensitivity and 84% specificity, resulting in 85.85% overall accuracy.

Conclusions:

This panel of miRNAs promoter methylation accurately detects UC in urine, comparing well with other promising epigenetic-based biomarkers. This may constitute the basis for a non-invasive assay to detect UC.

Cross Platform Standardisation of an Experimental Pipeline for Use in the Identification of Dysregulated Human Circulating MiRNAs

Introduction

Micro RNAs (miRNAs) are a class of highly conserved small non-coding RNAs that play an important part in the post-transcriptional regulation of gene expression. A substantial number of miRNAs have been proposed as biomarkers for diseases. While reverse transcriptase Real-time PCR (RT-qPCR) is considered the gold standard for the evaluation and validation of miRNA biomarkers, small RNA sequencing is now routinely being adopted for the identification of dysregulated miRNAs. However, in many cases where putative miRNA biomarkers are identified using small RNA sequencing, they are not substantiated when RT-qPCR is used for validation. To date, there is a lack of consensus regarding optimal methodologies for miRNA detection, quantification and standardisation when different platform technologies are used.

Materials and Methods

In this study we present an experimental pipeline that takes into consideration sample collection, processing, enrichment, and the subsequent comparative analysis of circulating small ribonucleic acids using small RNA sequencing and RT-qPCR.

Results, Discussion, Conclusions

Initially, a panel of miRNAs dysregulated in circulating blood from breast cancer patients compared to healthy women were identified using small RNA sequencing. MiR-320a was identified as the most dysregulated miRNA between the two female cohorts. Total RNA and enriched small RNA populations (<30 bp) isolated from peripheral blood from the same female cohort samples were then tested for using a miR-320a RT-qPCR assay. When total RNA was analysed with this miR-320a RT-qPCR assay, a 2.3-fold decrease in expression levels was observed between blood samples from healthy controls and breast cancer patients. However, upon enrichment for the small RNA population and subsequent analysis of miR-320a using RT-qPCR, its dysregulation in breast cancer patients was more pronounced with an 8.89-fold decrease in miR-320a expression. We propose that the experimental pipeline outlined could serve as a robust approach for the identification and validation of small RNA biomarkers for disease.

Circulating small noncoding RNAs as biomarkers of aging

Small noncoding RNAs (sncRNAs) mediate a variety of cellular functions in animals and plants. Deep sequencing has made it possible to obtain highly detailed information on the types and abundance of sncRNAs in biological specimens, leading to the discovery that sncRNAs circulate in the blood of humans and mammals. The most abundant types of circulating sncRNAs are microRNAs (miRNAs), 5' transfer RNA (tRNA) halves, and YRNA fragments, with minute amounts of other types that may nevertheless be significant. Of the more abundant circulating sncRNAs only miRNAs have well described functions, but characteristics of the others suggest specific processing and secretion as complexes that protect the RNA from degradation. The properties of circulating sncRNAs are consistent with their serving as signaling molecules, and investigations of circulating miRNAs support the view that they can enter cells and regulate cellular functions. The serum levels of specific sncRNAs change markedly with age, and these changes can be mitigated by calorie restriction (CR), indicating that levels are under physiologic control. The ability of circulating sncRNAs to transmit functions between cells and to regulate a broad spectrum of cellular functions, and the changes in their levels with age, implicate them in the manifestations of aging. Our understanding of the functions of circulating sncRNA, particularly in relation to aging, is currently at a very early stage; results to date suggest that more extensive investigation will yield important insights into mechanisms of aging.

siRNA-participated chemotherapy: an efficient and specific therapeutic against gastric cancer

PURPOSE

This study aims to investigate the role of siRNA silencing fibroblast growth factor receptor (FGFR) expression in promoting chemotherapy effect of gastric cancer and to explore its mechanism.

METHODS

Human gastric cancer cells MGC80-3 were divided into four groups: control group, cisplatin group (2 μg/L), cisplatin (2 μg/L) + siRNA group and siRNA group. The expressions of FGFR in four groups were detected by immunofluorescence. The cell proliferation and apoptosis were detected by MTT assay and flow cytometry. The protein expression levels of vascular endothelial growth factor receptor (VEGFR), caspase-3 and Bax were detected by Western blot. Further, animal model of gastric cancer was established and divided into four groups as in vitro experiment. The expression of FGFR mRNA in tumor tissue was detected by the real-time fluorescence quantitative polymerase chain reaction. The size of tumor was measured to analyze the effects of treatment. Histopathological detections were performed by hematoxylin and eosin staining and immunohistochemistry.

RESULTS

For in vitro experiment, significant decrease inFGFR expression, inhibition of proliferation and promotion of apoptosis were observed in siRNA-treated cells, so as cisplatin group. siRNA also resulted in the reduction of VEGFR and rise in apoptosis-related protein (caspase-3). As for the experiment in vivo, siRNA also suppressed the expression of FGFR and enhanced tumor shrink. Furthermore, the co-administration of siRNA and cisplatin revealed a more excellent antitumor effect than other therapies.

CONCLUSIONS

siRNA can effectively suppress FGFR expression and cell proliferation, but promote apoptosis in vitro and also inhibit tumor growth and FGFR production in vivo. siRNA-participated chemotherapy may provide an efficient therapeutic approach to treat gastric cancer.

miR-21 downregulated TCF21 to inhibit KISS1 in renal cancer

OBJECTIVE

To investigate whether the microRNA-21 gene (miR-21) could regulate renal cancer cells invasion by downregulation of TFC21 and KISS1.

METHODS

Quantitative real-time polymerase chain reaction was applied to evaluate the expression level of miRNA-21 in renal cancer and normal renal cell samples. The regulated effects of miR-21 to TCF21 were detected by Western blot after pre/anti-miR-21 was transfected to Caki-1 cells. The luciferase activity assay was used to reveal the predicted target gene of miR-21 was direct and specific. Small interfering RNA-TCF21 was transfected to Caki-1 cells to inhibit the expression of the TCF21 gene. Next, the expression of the KISS1 gene was detected by Western blot in Caki-1 cells with TCF21 gene silencing. The expression vector, pcDNA3.1-KISS1, was transfected to Caki-1 cells to upregulate the expression of the KISS1 gene. The invasion ability of Caki-1 cells with KISS1 overexpression was analyzed using the Transwell assay.

RESULTS

Our study showed that miR-21 was upregulated in human renal cell carcinoma specimens compared with its expression in normal renal cell specimens. Pre-miR-21 could upregulate the expression of miR-21 and downregulate the expression of TCF21, and anti-miR-21 showed the opposite effects. siRNA-TCF21 decreased the expression of the TCF21 protein, and the expression of KISS1 was downregulated in Caki-1 cells with TCF21 gene silencing. pcDNA3.1-KISS1 transfection upregulated the expression of the KISS1 protein, and the invasion ability of Caki-1 cells with KISS1 overexpression decreased markedly.

CONCLUSION

Aberrantly expressed miR-21 might regulate the TCF21-KISS1-associated renal cell carcinoma cell invasion pathway, and this miRNA signature could offer a novel potential therapeutic strategy for renal cell carcinoma.

Microarray expression profiling identifies genes with altered expression in Adolescent Idiopathic Scoliosis

PURPOSE

Adolescent Idiopathic Scoliosis (AIS) is considered a complex genetic disease, in which malfunctioning or dysregulation of one or more genes has been proposed to be responsible for the expressed phenotype. However, to date, no disease causing genes has been identified and the pathogenesis of AIS remains unknown. The aim of this study is, therefore, to identify specific molecules with differing expression patterns in AIS compared to healthy individuals.

METHODS

Microarray analysis and quantitative RT-PCR have examined differences in the gene transcription profile between primary osteoblasts derived from spinal vertebrae of AIS patients and those of healthy individuals.

RESULTS

There are 145 genes differentially expressed in AIS osteoblasts. A drastic and significant change has been noted particularly in the expression levels of Homeobox genes (HOXB8, HOXB7, HOXA13, HOXA10), ZIC2, FAM101A, COMP and PITX1 in AIS compared to controls. Clustering analysis revealed the interaction of these genes in biological pathways crucial for bone development, in particular in the differentiation of skeletal elements and structural integrity of the vertebrae.

CONCLUSIONS

This study reports on the expression of molecules that have not been described previously in AIS. We also provide for the first time gene interaction pathways in AIS pathogenesis. These genes are involved in various bone regulatory and developmental pathways and many of them can be grouped into clusters to participate in a particular biological pathway. Further studies can be built on our findings to further elucidate the association between different biological pathways and the pathogenesis of AIS.

Whither the etiopathogenesis (and scoliogeny) of adolescent idiopathic scoliosis? Incorporating presentations on scoliogeny at the 2012 IRSSD and SRS meetings

This paper aims to integrate into current understanding of AIS causation, etiopathogenetic information presented at two Meetings during 2012 namely, the International Research Society of Spinal Deformities (IRSSD) and the Scoliosis Research Society (SRS). The ultimate hope is to prevent the occurrence or progression of the spinal deformity of AIS with non-invasive treatment, possibly medical. This might be attained by personalised polymechanistic preventive therapy targeting the appropriate etiology and/or etiopathogenetic pathways, to avoid fusion and maintain spinal mobility. Although considerable progress had been made in the past two decades in understanding the etiopathogenesis of adolescent idiopathic scoliosis (AIS), it still lacks an agreed theory of etiopathogenesis. One problem may be that AIS results not from one cause, but several that interact with various genetic predisposing factors. There is a view there are two other pathogenic processes for idiopathic scoliosis namely, initiating (or inducing), and those that cause curve progression. Twin studies and observations of family aggregation have revealed significant genetic contributions to idiopathic scoliosis, that place AIS among other common disease or complex traits with a high heritability interpreted by the genetic variant hypothesis of disease. We summarize etiopathogenetic knowledge of AIS as theories of pathogenesis including recent multiple concepts, and blood tests for AIS based on predictive biomarkers and genetic variants that signify disease risk. There is increasing evidence for the possibility of an underlying neurological disorder for AIS, research which holds promise. Like brain research, most AIS workers focus on their own corner and there is a need for greater integration of research effort. Epigenetics, a relatively recent field, evaluates factors concerned with gene expression in relation to environment, disease, normal development and aging, with a complex regulation across the genome during the first decade of life. Research on the role of environmental factors, epigenetics and chronic non-communicable diseases (NCDs) including adiposity, after a slow start, has exploded in the last decade. Not so for AIS research and the environment where, except for monozygotic twin studies, there are only sporadic reports to suggest that environmental factors are at work in etiology. Here, we examine epigenetic concepts as they may relate to human development, normal life history phases and AIS pathogenesis. Although AIS is not regarded as an NCD, like them, it is associated with whole organism metabolic phenomena, including lower body mass index, lower circulating leptin levels and other systemic disorders. Some epigenetic research applied to Silver-Russell syndrome and adiposity is examined, from which suggestions are made for consideration of AIS epigenetic research, cross-sectional and longitudinal. The word scoliogeny is suggested to include etiology, pathogenesis and pathomechanism.

MicroRNAs in cancer diagnosis and therapy: from bench to bedside

Epigenetic changes, such as DNA methylation and histone modifications, regulate gene expression. It is speculated that investigating the fundamental epigenetic mechanisms and their gene regulation will promote a better understanding of cancer development. The idea of epigenetic modification has been extended to microRNAs (miRs). MiRs are single-stranded RNA molecules, about 19-25 ribonucleotides in length, which regulate gene expression post-transcriptionally and can act as tumor suppressors or oncogenes. We review the most recent findings related to their mechanisms of action, the modification of miR expression, and their relationship to cancer. We also discuss the potential application of miRs in the clinical setting, such as for biomarkers and therapy.

Ubiquinol decreases monocytic expression and DNA methylation of the pro-inflammatory chemokine ligand 2 gene in humans

BACKGROUND

Coenzyme Q₁₀ is an essential cofactor in the respiratory chain and serves in its reduced form, ubiquinol, as a potent antioxidant. Studies in vitro and in vivo provide evidence that ubiquinol reduces inflammatory processes via gene expression. Here we investigate the putative link between expression and DNA methylation of ubiquinol sensitive genes in monocytes obtained from human volunteers supplemented with 150 mg/ day ubiquinol for 14 days.

FINDINGS

Ubiquinol decreases the expression of the pro-inflammatory chemokine (C-X-C motif) ligand 2 gene (CXCL2) more than 10-fold. Bisulfite-/ MALDI-TOF-based analysis of regulatory regions of the CXCL2 gene identified six adjacent CpG islands which showed a 3.4-fold decrease of methylation status after ubiquinol supplementation. This effect seems to be rather gene specific, because ubiquinol reduced the expression of two other pro-inflammatory genes (PMAIP1, MMD) without changing the methylation pattern of the respective gene.

CONCLUSION

In conclusion, ubiquinol decreases monocytic expression and DNA methylation of the pro-inflammatory CXCL2 gene in humans. Current Controlled Trials ISRCTN26780329.

Adolescent idiopathic scoliosis (AIS), environment, exposome and epigenetics: a molecular perspective of postnatal normal spinal growth and the etiopathogenesis of AIS with consideration of a network approach and possible implications for medical therapy

Genetic factors are believed to play an important role in the etiology of adolescent idiopathic scoliosis (AIS). Discordant findings for monozygotic (MZ) twins with AIS show that environmental factors including different intrauterine environments are important in etiology, but what these environmental factors may be is unknown. Recent evidence for common chronic non-communicable diseases suggests epigenetic differences may underlie MZ twin discordance, and be the link between environmental factors and phenotypic differences. DNA methylation is one important epigenetic mechanism operating at the interface between genome and environment to regulate phenotypic plasticity with a complex regulation across the genome during the first decade of life. The word exposome refers to the totality of environmental exposures from conception onwards, comprising factors in external and internal environments. The word exposome is used here also in relation to physiologic and etiopathogenetic factors that affect normal spinal growth and may induce the deformity of AIS. In normal postnatal spinal growth we propose a new term and concept, physiologic growth-plate exposome for the normal processes particularly of the internal environments that may have epigenetic effects on growth plates of vertebrae. In AIS, we propose a new term and concept pathophysiologic scoliogenic exposome for the abnormal processes in molecular pathways particularly of the internal environment currently expressed as etiopathogenetic hypotheses; these are suggested to have deforming effects on the growth plates of vertebrae at cell, tissue, structure and/or organ levels that are considered to be epigenetic. New research is required for chromatin modifications including DNA methylation in AIS subjects and vertebral growth plates excised at surgery. In addition, consideration is needed for a possible network approach to etiopathogenesis by constructing AIS diseasomes. These approaches may lead through screening, genetic, epigenetic, biochemical, metabolic phenotypes and pharmacogenomic research to identify susceptible individuals at risk and modulate abnormal molecular pathways of AIS. The potential of epigenetic-based medical therapy for AIS cannot be assessed at present, and must await new research derived from the evaluation of epigenetic concepts of spinal growth in health and deformity. The tenets outlined here for AIS are applicable to other musculoskeletal growth disorders including infantile and juvenile idiopathic scoliosis.

Ubiquinol affects the expression of genes involved in PPARα signalling and lipid metabolism without changes in methylation of CpG promoter islands in the liver of mice

Coenzyme Q₁₀ is an essential cofactor in the respiratory chain and serves as a potent antioxidant in biological membranes. Recent studies in vitro and in vivo provide evidence that Coenzyme Q₁₀ is involved in inflammatory processes and lipid metabolism via gene expression. To study these effects at the epigenomic level, C57BL6J mice were supplemented for one week with reduced Coenzyme Q₁₀ (ubiquinol). Afterwards, gene expression signatures and DNA promoter methylation patterns of selected genes were analysed. Genome-wide transcript profiling in the liver identified 1112 up-regulated and 571 down-regulated transcripts as differentially regulated between ubiquinol-treated and control animals. Text mining and GeneOntology analysis revealed that the ”top 20” ubiquinol-regulated genes play a role in lipid metabolism and are functionally connected by the PPARα signalling pathway. With regard to the ubiquinol-induced changes in gene expression of about +3.14-fold (p≤0.05), +2.18-fold (p≤0.01), and −2.13-fold (p≤0.05) for ABCA1, ACYP1, and ACSL1 genes, respectively, hepatic DNA methylation analysis of 282 (sense orientation) and 271 (antisense) CpG units in the respective promoter islands revealed no significant effect of ubiquinol. In conclusion, ubiquinol affects the expression of genes involved in PPARα signalling and lipid metabolism without changing the promoter DNA methylation status in the liver of mice.

Environmental and epigenetic effects upon preimplantation embryo metabolism and development

In vitro fertilization has provided a unique window into the metabolic processes that drive embryonic growth and development from a fertilized ovum to a competent blastocyst. Post-fertilization development is dependent upon a dramatic reshuffling of the parental genomes during meiosis, as well as epigenetic changes that provide a new and autonomous set of instructions to guide cellular differentiation both in the embryo and beyond. Although early literature focused simply on the substrates and culture conditions required for progress through embryonic development, more recent insights lead us to suggest that the surrounding environment can alter the epigenome, which can, in turn, impact upon embryonic metabolism and developmental competence.

Chimeric aptamers in cancer cell-targeted drug delivery

Aptamers are single-stranded structured oligonucleotides (DNA or RNA) that can bind to a wide range of targets ("apatopes") with high affinity and specificity. These nucleic acid ligands, generated from pools of random-sequence by an in vitro selection process referred to as systematic evolution of ligands by exponential enrichment (SELEX), have now been identified as excellent tools for chemical biology, therapeutic delivery, diagnosis, research, and monitoring therapy in real-time imaging. Today, aptamers represent an interesting class of modern Pharmaceuticals which with their low immunogenic potential mimic extend many of the properties of monoclonal antibodies in diagnostics, research, and therapeutics. More recently, chimeric aptamer approach employing many different possible types of chimerization strategies has generated more stable and efficient chimeric aptamers with aptamer-aptamer, aptamer-nonaptamer biomacromolecules (siRNAs, proteins) and aptamer-nanoparticle chimeras. These chimeric aptamers when conjugated with various biomacromolecules like locked nucleic acid (LNA) to potentiate their stability, biodistribution, and targeting efficiency, have facilitated the accurate targeting in preclinical trials. We developed LNA-aptamer (anti-nucleolin and EpCAM) complexes which were loaded in iron-saturated bovine lactofeerin (Fe-blf)-coated dopamine modified surface of superparamagnetic iron oxide (Fe₃O₄) nanoparticles (SPIONs). This complex was used to deliver the specific aptamers in tumor cells in a co-culture model of normal and cancer cells. This review focuses on the chimeric aptamers, currently in development that are likely to find future practical applications in concert with other therapeutic molecules and modalities.

Bioluminescent stem-loop probes for highly sensitive nucleic acid detection

Here, we report the first bioluminescent stem-loop probe, which is 50 times more sensitive and able to achieve a LOD 25 times lower than fluorescent stem-loop probes. Chemical generation of a signal from Renilla luciferase reduces background noise for improved quantitative utility in nucleic acid biomarker detection.

Deep sequencing reveals novel microRNAs and regulation of microRNA expression during cell senescence

In cell senescence, cultured cells cease proliferating and acquire aberrant gene expression patterns. MicroRNAs (miRNAs) modulate gene expression through translational repression or mRNA degradation and have been implicated in senescence. We used deep sequencing to carry out a comprehensive survey of miRNA expression and involvement in cell senescence. Informatic analysis of small RNA sequence datasets from young and senescent IMR90 human fibroblasts identifies many miRNAs that are regulated (either up or down) with cell senescence. Comparison with mRNA expression profiles reveals potential mRNA targets of these senescence-regulated miRNAs. The target mRNAs are enriched for genes involved in biological processes associated with cell senescence. This result greatly extends existing information on the role of miRNAs in cell senescence and is consistent with miRNAs having a causal role in the process.