Ladybird Homeobox Research Articles

LncRNA LBX2-AS1 promotes proliferation and migratory capacity of clear cell renal cell carcinoma through mitophagy

BackgroundLong non-coding RNAs (lncRNAs) have been extensively investigated in the field of cancer, among which, lncRNA ladybird homeobox 2-antisense RNA 1 (LBX2-AS1) has been demonstrated to exert carcinogenic effects on a variety of malignancies. However, the biological functions of LBX2-AS1 in clear cell renal cell carcinoma (ccRCC) have not been explicitly elucidated.MethodsArraystar lncRNA chip and qRT-PCR verify the expression of LncRNA LBX2-AS1 in ccRCC. CCK-8 assay and cell cloning assay were used to assess the proliferative capacity of ccRCC cells. Migration abilities were quantified by scratch assay and transwell assay. Potential molecular signaling pathways were determined by high-throughput whole transcriptomics analysis. WB analysis was performed to validate the relationship between LBX2-AS1 and key molecules of mitophagy pathway. The effect of LBX2-AS1 on mitophagy was observed by laser confocal microscopy. Rescue experiments further validated the role of downstream gene FOXO3A in the LBX2-AS1 signaling pathway. Finally, the authentic effect of LBX2-AS1 was verified in vivo.ResultsLncRNA LBX2-AS1 was over expressed in ccRCC tissues and could enhance the proliferation and migration of ccRCC cells. Autophagic pathway was identified as a possible mechanism involved in the oncogenic effect of LBX2-AS1. Mitophagy levels were observed in LBX2-AS1 low-expressing cells through laser confocal microscopy. Knockdown of LBX2-AS1 significantly elevated mitophagy levels as observed using laser confocal microscopy and led to FOXOA3 decreasing in and BNIP3L and LC3 enrichment. Meanwhile, LBX2-AS1 knocking down dampened the proliferation of ccRCC cells in vivo.

Association of LBX1 Gene Methylation Level with Disease Severity in Patients with Idiopathic Scoliosis: Study on Deep Paravertebral Muscles.

Idiopathic scoliosis (IS) is a multifactorial disease with a genetic background. The association of Ladybird Homeobox 1 (LBX1) polymorphisms with IS has been proven in multiple studies. However, the epigenetic mechanisms have not been evaluated. This study aimed to evaluate the LBX1 methylation level in deep paravertebral muscles in order to analyze its association with IS occurrence and/or IS severity. Fifty-seven IS patients and twenty non-IS patients were examined for the paravertebral muscles’ methylation level of the LBX1 promoter region. There was no significant difference in methylation level within paravertebral muscles between patients vs. controls, except for one CpG site. The comparison of the paravertebral muscles’ LBX1 promoter region methylation level between patients with a major curve angle of ≤70° vs. >70° revealed significantly higher methylation levels in 17 of 23 analyzed CpG sequences at the convex side of the curvature in patients with a major curve angle of >70° for the reverse strand promoter region. The association between LBX1 promoter methylation and IS severity was demonstrated. In patients with severe IS, the deep paravertebral muscles show an asymmetric LBX1 promoter region methylation level, higher at the convex scoliosis side, which reveals the role of locally acting factors in IS progression.

The Landscape of DNA Methylation Generates Insight Into Epigenetic Regulation of Differences Between Slow-Twitch and Fast-Twitch Muscles in Pseudocaranx dentex

Skeletal muscles of teleost are mainly composed of slow-twitch muscles (SM) and fast-twitch muscles (FM) differed in contractile properties, metabolic capacities, and regeneration rate. The transcriptional regulatory mechanisms that control different muscle types have been elucidated in teleost according to transcriptome between SM and FM. However, the differences between SM and FM were affected not only by genotype but also by complicated epigenetic effects, including DNA methylation, which usually regulates genes in transcription level. To determine the essential role of DNA methylation in the regulation of different muscle types, we analyzed whole-genome methylation profiles of pelagic migratory fish Pseudocaranx dentex with abundant and well-separated SM and integrated DNA methylation profiles with the previously obtained transcriptome data. A total of 4,217 differentially methylated genes (DMGs) were identified, of which 3,582 were located in the gene body and 635 in the promoter. These DMGs mainly participated in muscle metabolite and cell junction. Enriched cell junction pathway reflected different capillary distribution between SM and FM. Through comprehensive analysis of methylome and transcriptome, 84 differentially expressed genes (DEGs) showed significant methylation variation in promoters between SM and FM, indicating that their expression was regulated by DNA methylation. Hypomethylated and highly expressed oxygen storage protein Myoglobin (myg) in SM indicated demethylation of myg promoter could upregulate its expression, thus increasing O2 supplying and meeting oxygen demands of SM. Hypermethylated and lowly expressed tnn (Troponin) and rlc (myosin regulatory light chain) in SM may be associated with low mobility of myosin cross bridges, which lead to slower and less frequent muscle contraction in SM than in FM. In addition, hypomethylated and highly expressed lbx1 (Ladybird homeobox protein homolog 1) and epo (erythropoietin) may be related to increased satellite cell numbers, and Semaphorin/Plexin genes may be related to higher rate of neuromuscular connection reconstruction, which further promote high muscle regeneration efficiency in SM. Our study elucidated the potential DNA methylation mechanisms that regulate physiological characteristics differences between SM and FM, which could facilitate our understanding of skeletal muscle adaptation in pelagic migratory fishes and further enrich the theoretical basis for the study of physiological characteristics and adaptive evolution in teleost fishes.

LBX2 expression and outcomes in patients with colon adenocarcinoma.

158 Background: Colon adenocarcinoma (COAD) is one of the most common gastrointestinal cancers worldwide. Previous studies found that Ladybird homeobox 1 (LBX1) and Ladybird homeobox 2 (LBX2), were involved in the progress of several types of cancer. However, studies on their roles in cancers, such as COAD, are very limited. Thus, this study was performed to explore their roles in COAD. Methods: RNA-sequencing FPKM data and corresponding clinical information of 480 tumor tissues of COAD and 41 normal tissues were obtained from The Cancer Genome Atlas (TCGA). The ‘limma’ package was used to compare the expression differences of LBX1 and LBX2 between the normal and cancer tissues using Wilcoxon rank-sum test. Analysis of overall survival (OS), disease specific survival (DSS), and progression free interval (PFI) were conducted by Kaplan–Meier (K–M) method via ‘survminer’ package. Univariate Cox hazard regression analysis of OS was applied to five clinicopathological variables from T stage, N stage, M stage, pathologic stage, CEA level, as well as the expression level of family members of LBX that are overexpressed and associated with worsening survival outcomes, by using ‘survival’ package. Furthermore, a nomogram was also visualized by the R ‘rms’ package and ‘survival’ package to predict the 1-, 3-, and 5-year OS and individual predictors. Results: The expression of LBX2 (p = 8.1e-20) was upregulated in COAD tissues compared with normal tissues, while no statistically significant difference of expression between normal tissues and tumor was found for LBX1 (p = 0.06). Further survival analysis found that higher expression of LBX2 was associate with worse OS (HR = 2.45, 95%CI 1.62-3.71, p < 0.001), DSS (HR = 2.34, 95%CI 1.39-3.96, p = 0.001), and PFI (HR = 1.48, 95%CI 1.04-2.10, p = 0.03). Univariate Cox hazard regression analysis showed that N1, N2, N3, M1, pathologic stage III and IV, CEA level>5, and high expression level of LBX2 were associated with worse OS (all p < 0.05). The nomogram based on six clinicopathological variables (T stage, N stage, M stage, pathologic stage, CEA level, and LBX2 expression level) and 1-, 3-, 5-year OS probabilities were developed, with concordance index (C-index) of 0.795(0.755-0.834), indicating its prediction value and sufficient discrimination ability, as C-index was more than 0.7. The calibration curves of 1-, 3-, and 5-year demonstrated the consistency of our results and the predictive values, indicating satisfactory performance for this nomogram. Moreover1-, 3-, 5-year AUCs of LBX2-based nomogram were 0.805, 0.831, and 0.774, showing a moderate accuracy. Conclusions: LBX2 are upregulated in COAD tumor samples, and its higher expression is associated with worsening OS, DSS, and PFI. The LBX2-based monogram developed by this study might help predict the OS possibilities for COAD patients. LBX2 can be a potential diagnostic and prognostic marker, and therapeutic marker in COAD.

Evolution of lbx spinal cord expression and function.

Ladybird homeobox (Lbx) transcription factors have crucial functions in muscle and nervous system development in many animals. Amniotes have two Lbx genes, but only Lbx1 is expressed in spinal cord. In contrast, teleosts have three lbx genes and we show here that zebrafish lbx1a, lbx1b, and lbx2 are expressed by distinct spinal cell types, and that lbx1a is expressed in dI4, dI5, and dI6 interneurons, as in amniotes. Our data examining lbx expression in Scyliorhinus canicula and Xenopus tropicalis suggest that the spinal interneuron expression of zebrafish lbx1a is ancestral, whereas lbx1b has acquired a new expression pattern in spinal cord progenitor cells. lbx2 spinal expression was probably acquired in the ray-finned lineage, as this gene is not expressed in the spinal cords of either amniotes or S. canicula. We also show that the spinal function of zebrafish lbx1a is conserved with mouse Lbx1. In zebrafish lbx1a mutants, there is a reduction in the number of inhibitory spinal interneurons and an increase in the number of excitatory spinal interneurons, similar to mouse Lbx1 mutants. Interestingly, the number of inhibitory spinal interneurons is also reduced in lbx1b mutants, although in this case the number of excitatory interneurons is not increased. lbx1a;lbx1b double mutants have a similar spinal interneuron phenotype to lbx1a single mutants. Taken together these data suggest that lbx1b and lbx1a may be required in succession for correct specification of dI4 and dI6 spinal interneurons, although only lbx1a is required for suppression of excitatory fates in these cells.

The Lbx1 lineage differentially contributes to inhibitory cell types of the dorsal cochlear nucleus, a cerebellum-like structure, and the cerebellum.

The dorsal cochlear nucleus (DCN) is a mammalian-specific nucleus of the auditory system. Anatomically, it is classified as a cerebellum-like structure. These structures are proposed to share genetic programs with the cerebellum. Previous analyses demonstrated that inhibitory serial sister cell types (SCTs) of the DCN and cerebellum are derived from the pancreatic transcription factor 1a (Ptf1a) lineage. Postmitotic neurons of the Ptf1a lineage often express the transcription factor Ladybird homeobox protein homolog 1 (Lbx1) which is involved in neuronal cell fate determination. Lbx1 is therefore an attractive candidate for a further component of the genetic program shared between the DCN and cerebellum. Here, we used cell-type specific marker analysis in combination with an Lbx1 reporter mouse line to analyze in both tissues which cell types of the Ptf1a lineage express Lbx1. In the DCN, stellate cells and Purkinje-like cartwheel cells were part of the Lbx1 lineage and Golgi cells were not, as determined by cell counts. In contrast, in the cerebellum, stellate cells and Golgi cells were part of the Lbx1 lineage and Purkinje cells were not. Hence, two out of three phenotypically similar cell types differed with respect to their Lbx1 expression. Our study demonstrates that Lbx1 is differentially recruited to the developmental genetic program of inhibitory neurons both within a given tissue and between the DCN and cerebellum. The differential expression of Lbx1 within the DCN and the cerebellum might contribute to the genetic individuation of the inhibitory SCTs to adapt to circuit specific tasks.

LncRNA LBX2-AS1 facilitates abdominal aortic aneurysm through miR-4685-5p/LBX2 feedback loop

Long noncoding RNAs (LncRNAs) are involved in multiple processes of human malignancy, and emerge as crucial molecules in RNA biology. However, the function of lncRNAs has not been well illustrated in abdominal aortic aneurysm (AAA). In this research, the effects of dysregulated ladybird homeobox 2 antisense RNA 1 (LBX2-AS1) or ladybird homeobox 2 (LBX2) on vascular smooth muscle cell (VSMC) biological processes were surveyed via cell counting kit-8 (CCK-8), methyl thiazolyl tetrazolium (MTT), terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) and caspase-3 activity assays. LBX2-AS1 and LBX2 both possessed pro-apoptosis and anti-proliferation functions in AAA. Mechanically, the regulation role of LBX2-AS1 on miR-4685-5p or that of miR-4685-5p on LBX2 was investigated by quantitative real-time polymerase chain reaction (qRT-PCR). Additionally, the competing endogenous RNA (ceRNA) network was confirmed by luciferase reporter, RNA pull-down, and RNA immunoprecipitation (RIP) assays. LBX2-AS1 sequestered miR-4685-5p to release LBX2 expression via ceRNA mechanism. Further, LBX2 could act as a transcriptional activator of LBX2-AS1. A positive feedback loop was formed by LBX2-AS1, miR-4685-5p and LBX2, deteriorating AAA formation and progression. To sum up, our data suggested that LBX2-AS1, miR-4685-5p and LBX2 constituted a positive feedback loop in promoting AAA development, implying a potential usage of LBX2-AS1/miR-4685-5p/LBX2 axis in AAA management.

Association between ladybird homeobox 1 gene polymorphisms and adolescent idiopathic scoliosis: A MOOSE-compliant meta-analysis.

The Ladybird Homeobox 1 (LBX1) gene has been implicated in the etiology of adolescent idiopathic scoliosis (AIS). The association between LBX1 gene polymorphisms and AIS has been investigated in several studies. However, these findings have yield contradictory results rather than conclusive evidence.This study is to provide a meta-analysis of the published case-control studies on the association between LBX1 gene polymorphisms and AIS in Asian and Caucasian populations.This meta-analysis conformed to the Meta-Analysis of Observational Studies in Epidemiology (MOOSE) guidelines. We conducted a literature research on PubMed, Embase, Web of Science, and Cochrane Library until February 10, 2018. We included all case-control or cohort studies about association between LBX1 gene polymorphisms and AIS. The Risk Of Bias In Non-randomised Studies-of Interventions and Critical Appraisal Skills Programme were used to evaluate the risk of bias and study quality. We assessed the strength of association by pooled odds ratios (ORs) and 95% confidence intervals (CIs) in all genetic models under a fixed-effect model or random-effect model. We further performed subgroup analysis by ethnicity and sex. Sensitivity analysis and publication bias were also undertaken.A total of 10 studies (11,411 cases and 26,609 controls) were included in this meta-analysis. The pooled results showed a statistically significant association between LBX1 gene polymorphisms and AIS (for rs11190870, T vs C, OR = 1.54, 95% CI = 1.48-1.61, P < .00001; for rs625039, G vs A, OR = 1.50, 95% CI: 1.38-1.62; P < .00001; for rs678741, G vs A, OR = 0.74, 95% CI: 0.63-0.86; P < .0001; for rs11598564, G vs A, OR = 1.41, 95% CI: 1.31-1.51; P < .0001). For stratified analyses by ethnicity and sex, robust significant associations were detected in Asian and Caucasian populations, and in women and men under all genetic models.T allele of rs11190870 and G alleles of rs625039 and rs11598564 represent risk factors for AIS, but G allele of rs678741 may play a protective role in the occurrence of AIS. Further research is needed to confirm this finding and to understand its implications.

Paraspinal muscle ladybird homeobox 1 (LBX1) in adolescent idiopathic scoliosis: a cross-sectional study

BACKGROUND CONTEXTAdolescent idiopathic scoliosis (AIS) is the leading cause of spinal deformity in adolescents globally. Recent evidence from genome-wide association studies has implicated variants in or near the ladybird homeobox 1 (LBX1) gene, encoding the ladybird homeobox 1 transcription factor, in AIS development. This gene plays a critical role in guiding embryonic neurogenesis and myogenesis and is vital in muscle mass determination. Despite the confirmation of the role for LBX1 gene variants in the development of AIS, the biological basis of LBX1 contribution to AIS remains mostly unknown. PURPOSETo investigate the potential role of LBX1 in driving spinal curving, curve laterality, and progression through muscle-based mechanisms in AIS patients by analyzing its gene and protein expression. STUDY DESIGNThis is a cross-sectional study using clinical data and biological samples from the Immunometabolic CONnections to Scoliosis study (ICONS study). PATIENT SAMPLETwenty-five patients with AIS provided informed consent. Paraspinal muscle biopsies from the maximal points of concavity and convexity for gene expression and protein analysis were obtained at the start of corrective spinal surgery. OUTCOME MEASURESThe outcome measures included the detection of paraspinal muscle LBX1 mRNA abundance and LBX1 protein expression and the correlation of the latter with age, sex, and curve severity. METHODSThe measurement of mRNA abundance was done using quantitative real-time polymerase chain reaction (qRT-PCR). Additionally, protein lysates from the biopsied muscle samples were probed with a monoclonal LBX1 antibody to compare the muscle protein levels on either side of the scoliotic curve by western blot. This study received funding from the Division of Orthopedics, Department of Surgery, McMaster University, Hamilton, Ontario, Canada ($39,900 CAN for 2 years). The authors have no conflicts of interest to disclose. RESULTSLBX1 mRNA abundance (concave 2.98±0.87, convex 3.40±1.10, p value 0.73) and protein expression (concave 1.20±0.13, convex 1.21±0.10, p value 0.43) were detected on both sides of the scoliotic curve at equivalent levels. The expression of LBX1 protein did not correlate with age (concave: correlation coefficient 0.32, p value 0.12; convex: correlation coefficient 0.08, p value 0.69), sex (concave: correlation coefficient −0.03, p value 0.08; convex: correlation coefficient 0.07, p value 0.72), or the severity of spinal curving measured using the Cobb angle (concave: correlation coefficient −0.16, p value 0.45; convex: correlation coefficient −0.08, p value 0.69). CONCLUSIONSLBX1 is expressed in erector spinae muscles, and its levels are equal in muscles on both sides of the scoliotic curve in AIS. The expression of LBX1 on the convex and concave sides of the scoliotic curve did not correlate with age, sex, or the severity of spinal curving. The molecular mechanisms by which LBX1contributes to the development and propagation of AIS need to be explored further in muscle and other tissues.

LBX2-AS1 is activated by ZEB1 and promotes the development of esophageal squamous cell carcinoma by interacting with HNRNPC to enhance the stability of ZEB1 and ZEB2 mRNAs

Long non-coding RNAs (lncRNAs) are a group of transcripts, which can regulate the progression of esophageal squamous cell carcinoma (ESCC). According to the data of TCGA, Ladybird homeobox 2 antisense RNA 1 (LBX2-AS1) is a highly expressed lncRNA in ESCC samples. Herein, we chose it for further study. Furtherly, dysregulation of LBX2-AS1 was identified in ESCC tissues with metastasis. Loss-of function assays were conducted and revealed that LBX2-AS1 knockdown suppressed ESCC cell migration and epithelial-mesenchymal transition (EMT). Zinc finger E-box binding homeobox 1 (ZEB1) and zinc finger E-box binding homeobox 2 (ZEB2) are two EMT-related transcription factors. Since LBX2-AS1 promoted the EMT progress and simultaneously enhanced the level of ZEB1 and ZEB2, we further investigated whether LBX2-AS1 promoted cell migration and EMT in ESCC by regulating ZEB1 and ZEB2. Mechanism investigations revealed that RNA binding protein heterogeneous nuclear ribonucleoprotein C (HNRNPC) could interact with LBX2-AS1, ZEB1 and ZEB2, simultaneously. The similar function of HNRNPC in regulating migration and EMT process was demonstrated. ZEB1 has been reported as a positive transcriptional regulator of lncRNA. Therefore, further mechanism analysis was made to demonstrate whether ZEB1 could regulate the transcription of LBX2-AS1. Collectively, our data showed that ZEB1-induced upregulation of LBX2-AS1 promoted cell migration and EMT process in ESCC via enhancing the stability of ZEB1 and ZEB2.

Positive association between the progression of idiopathic scoliosis and the common variant near the LBX1 gene in Southeast European population

This report investigates the positive association between curve progression of Southeast European population and one of the most significant polymorphisms of idiopathic scoliosis (IS). The association between rs11190870 near the ladybird homeobox 1 (LBX1) gene, the curve severity (case-control study) and the curve pattern (case-only study) was explored among 155 IS Caucasian patients and 254 unrelated controls. The genotyping of rs11190870 was carried out by the TaqMan real-time amplification technology. The results revealed the existence of a statistically significant association between rs11190870, downstream of the LBX1 gene and IS predisposition and progression in the population sample. The case-only analysis indicated also that the genetic variant rs11190870 is not correlated to a certain idiopathic curve pattern. Based on the obtained data, rs11190870 could be regarded as a predisposing and modifying genetic factor for IS in patients of Southeast European descent. In addition, replication studies are necessary to investigate the possible relationship between the LBX1 locus and certain subtypes of IS in specific population groups. Clinical relevance should be pursued further, together with the molecular genetic identification of prognostic markers, as a contemporary approach that would make an early treatment including minimally invasive procedures.

A Replication Study for Association of LBX1 Locus With Adolescent Idiopathic Scoliosis in French-Canadian Population.

A case-control association study. To investigate the relationship between LBX1 (lady bird homeobox1) polymorphisms and adolescent idiopathic scoliosis (AIS) in French-Canadian population. It is widely accepted that genetic factors contribute to AIS. Although the LBX1 locus is so far the most successfully replicated locus in different AIS cohorts, these associations were replicated mainly in Asian populations, with few studies in Caucasian populations of European descent. We recruited 1568 participants (667 AIS patients and 901 healthy controls) in the French-Canadian population. Genomic data were generated using the Illumina Human Omni 2.5M BeadChip. An additional 121 AIS cases and 51 controls were genotyped for specific single-nucleotide polymorphisms (SNPs) by multiplex polymerase chain reaction using standard procedures. BEAGLE 3 was used to impute the following markers: rs7893223, rs11190878, and rs678741 against the 1000-genomes European cohort phased genotypes given that they were absent in our genome wide association studies (GWAS) panel. Resulting genotypes were combined then used for single marker and haplotyped-based association. Four markers showed association with AIS in our cohort at this locus; rs11190870 the most studied marker, rs7893223, rs594791, and rs11190878. When we restricted the analysis to severe cases only, four additional SNPs showed associations: rs11598177, rs1322331, rs670206, and rs678741. In addition, we analyzed the associations of the observed haplotypes and dihaplotypes formed by these SNPs. The haplotype TTAAGAAA and its homozygous dihaplotype showed the highest association with our severe group and was the highest risk haplotype. The haplotype CCGCAGGG was significantly more associated with the control group, and its homozygous or heterozygous dihaplotype was less frequent in the severe group compared with the control group, suggesting that CCGCAGGG may represent a protective haplotype. We have replicated the association of the LBX1 locus with AIS in French-Canadian population, a novel European descent cohort, which is known for its unique genetic architecture. 3.

Phosphorylation of Lbx1 controls lateral myoblast migration into the limb

The migration of limb myogenic precursors from limb level somites to their ultimate site of differentiation in the limb is a paradigmatic example of a set of dynamic and orchestrated migratory cell behaviours. The homeobox containing transcription factor ladybird homeobox 1 (Lbx1) is a central regulator of limb myoblast migration, null mutations of Lbx1 result in severe disruptions to limb muscle formation, particularly in the distal region of the limb in mice (Gross et al., 2000). As such Lbx1 has been hypothesized to control lateral migration of myoblasts into the distal limb anlage. It acts as a core regulator of the limb myoblast migration machinery, controlled by Pax3. A secondary role for Lbx1 in the differentiation and commitment of limb musculature has also been proposed (Brohmann et al., 2000; Uchiyama et al., 2000). Here we show that lateral migration, but not differentiation or commitment of limb myoblasts, is controlled by the phosphorylation of three adjacent serine residues of LBX1. Electroporation of limb level somites in the chick embryo with a dephosphomimetic form of Lbx1 results in a specific defect in the lateral migration of limb myoblasts. Although the initial delamination and migration of myoblasts is unaffected, migration into the distal limb bud is severely disrupted. Interestingly, myoblasts undergo normal differentiation independent of their migratory status, suggesting that the differentiation potential of hypaxial muscle is not regulated by the phosphorylation state of LBX1. Furthermore, we show that FGF8 and ERK mediated signal transduction, both critical regulators of the developing limb bud, have the capacity to induce the phosphorylation of LBX1 at these residues. Overall, this suggests a mechanism whereby the phosphorylation of LBX1, potentially through FGF8 and ERK signalling, controls the lateral migration of myoblasts into the distal limb bud.

Associations of LBX1 gene and adolescent idiopathic scoliosis susceptibility: a meta-analysis based on 34,626 subjects.

BackgroundThe results of studies investigating the association between the ladybird homeobox 1 (LBX1) gene polymorphisms and the risk of adolescent idiopathic scoliosis (AIS) are not all the same. As such, we performed a meta-analysis to estimate the association between LBX1 gene polymorphisms and AIS susceptibility.MethodsRelevant studies published before 15 November 2015 were identified by searching PubMed, EMBASE, ISI web of knowledge, EBSCO, CNKI and CBM. The strength of relationship was assessed by using odds ratios (ORs) and 95 % confidence interval (CI).ResultsA total number of eight case-control studies including 10,088 cases and 24,538 controls were identified. The results showed that T allele of rs111090870 increased AIS susceptibility in Asians (T vs. C, OR = 1.22, 95 % CI: 1.16–1.29, P < 0.001), Caucasians (T vs. C, OR = 1.17, 95 % CI: 1.14–1.21, P < 0.001) and in female (T vs. C, OR = 1.21, 95 % CI: 1.17–1.25, P < 0.001). The G allele of rs678741 decreased AIS risk in female (G vs. A, OR = 0.83, 95 % CI: 0.81–0.85, P < 0.001), and the G allele of the rs625039 increased AIS susceptibility in Asians (G vs. A, OR = 1.14, 95 % CI: 1.11–1.17, P < 0.001).ConclusionsOur meta-analysis provides evidence that rs111090870, rs678741 and rs625039 polymorphisms near LBX1 gene are associated with AIS susceptibility in some populations. However, our findings are based on only a limited number of studies.Electronic supplementary materialThe online version of this article (doi:10.1186/s12891-016-1139-z) contains supplementary material, which is available to authorized users.

Functional Investigation of a Non-coding Variant Associated with Adolescent Idiopathic Scoliosis in Zebrafish: Elevated Expression of the Ladybird Homeobox Gene Causes Body Axis Deformation.

Previously, we identified an adolescent idiopathic scoliosis susceptibility locus near human ladybird homeobox 1 (LBX1) and FLJ41350 by a genome-wide association study. Here, we characterized the associated non-coding variant and investigated the function of these genes. A chromosome conformation capture assay revealed that the genome region with the most significantly associated single nucleotide polymorphism (rs11190870) physically interacted with the promoter region of LBX1-FLJ41350. The promoter in the direction of LBX1, combined with a 590-bp region including rs11190870, had higher transcriptional activity with the risk allele than that with the non-risk allele in HEK 293T cells. The ubiquitous overexpression of human LBX1 or either of the zebrafish lbx genes (lbx1a, lbx1b, and lbx2), but not FLJ41350, in zebrafish embryos caused body curvature followed by death prior to vertebral column formation. Such body axis deformation was not observed in transcription activator-like effector nucleases mediated knockout zebrafish of lbx1b or lbx2. Mosaic expression of lbx1b driven by the GATA2 minimal promoter and the lbx1b enhancer in zebrafish significantly alleviated the embryonic lethal phenotype to allow observation of the later onset of the spinal curvature with or without vertebral malformation. Deformation of the embryonic body axis by lbx1b overexpression was associated with defects in convergent extension, which is a component of the main axis-elongation machinery in gastrulating embryos. In embryos overexpressing lbx1b, wnt5b, a ligand of the non-canonical Wnt/planar cell polarity (PCP) pathway, was significantly downregulated. Injection of mRNA for wnt5b or RhoA, a key downstream effector of Wnt/PCP signaling, rescued the defective convergent extension phenotype and attenuated the lbx1b-induced curvature of the body axis. Thus, our study presents a novel pathological feature of LBX1 and its zebrafish homologs in body axis deformation at various stages of embryonic and subsequent growth in zebrafish.

Current progress in genetic research of adolescent idiopathic scoliosis.

Previous genetic linkage analysis and candidate gene association analysis have unveiled dozens of variants associated with the development of adolescent idiopathic scoliosis (AIS), which however can seldom be replicated in different ethnics. Recently, two genome-wide association studies of AIS performed in Japan revealed that ladybird homeobox 1 (LBX1) gene and G protein-coupled receptor 126 (GPR126) gene could play a role in the etiopathogenesis of the disease. Since the association between these two genes and AIS were successfully validated in the Caucasian and the Chinese population, LBX1 gene and GPR126 gene were the most reliable genetic variants underling the development of AIS.

Tissue-specific derepression of TCF/LEF controls the activity of the Wnt/β-catenin pathway.

Upon stimulation by Wnt ligands, the canonical Wnt/β-catenin signalling pathway results in the stabilization of β-catenin and its translocation into the nucleus to form transcriptionally active complexes with sequence-specific DNA-binding T-cell factor/lymphoid enhancer factor (TCF/LEF) family proteins. In the absence of nuclear β-catenin, TCF proteins act as transcriptional repressors by binding to Groucho/Transducin-Like Enhancer of split (TLE) proteins that function as co-repressors by interacting with histone deacetylases whose activity leads to the generation of transcriptionally silent chromatin. Here we show that the transcription factor Ladybird homeobox 2 (Lbx2) positively controls the Wnt/β-catenin signalling pathway in the posterior lateral and ventral mesoderm of the zebrafish embryo at the gastrula stage, by directly interfering with the binding of Groucho/TLE to TCF, thereby preventing formation of transcription repressor complexes. These findings reveal a novel level of regulation of the canonical Wnt/β-catenin signalling pathway occurring in the nucleus and involving tissue-specific derepression of TCF by Lbx2.

A genome-wide association scan in pig identifies novel regions associated with feed efficiency trait1

Feed conversion ratio (FCR) is an economically important trait in pigs, and feed accounts for a significant proportion of the costs involved in pig production. In this study we used a high-density SNP chip panel, Porcine SNP60 BeadChip, to identify the association between FCR and SNP markers and to study the genetic architecture of the trait. After quality control, a total of 30,847 SNP that could be mapped to the 18 porcine autosomes (SSC) using the pig genome assembly 10.2 were used in the analyses. Deregressed estimated breeding value was used as the response variable. A total of 3,071 Duroc pigs had both FCR data and genotype data. The linkage disequilibrium (r(2)) between adjacent markers was 0.56. Two association mapping approaches were used: a linear mixed model (LMM) based on single-locus regression analysis and a Bayesian variable selection approach (BVS). A total of 79 significant (P < 0.0001) SNP associations on 6 chromosomes were identified by LMM analyses. Out of these, 10 SNP crossed the genome-wide significance threshold. These 10 SNP were all located on SSC 4 and 14. In the BVS analysis, a total of 44 SNP located on 12 chromosomes had posterior probability more than or equal to 0.05 (i.e., Bayes factor ≥ 10). Thirteen SNP were identified by both LMM and BVS. These 13 SNP were located on 4 chromosomes: SSC 4, 7, 8, and 14. Hypoxia inducible factor 1, alpha subunit inhibitor (HIF1AN) and ladybird homeobox 1 (LBX1) are 2 possible candidate genes affecting FCR on SSC 4 and 14, respectively. The study provides a list of SNP associated with FCR and also offers valuable information on the genetic architecture and candidate genes for this trait.

SNP rs11190870 near LBX1 is associated with adolescent idiopathic scoliosis in southern Chinese

A study was conducted to validate the most significant single nucleotide polymorphism (SNP) from a genome-wide association study of Japanese adolescent idiopathic scoliosis (AIS) patients in an independent southern Chinese population. In total, 300 AIS patients fulfilled the clinical criteria and 788 controls with MRI scans of the spine were included in the replication study. We employed case-control analysis to study the association of SNP rs11190870 near LBX1 (ladybird homeobox 1) with AIS in a southern Chinese population. The results suggest that SNP rs11190870 is significantly associated with AIS (P=9.1 × 10(-10); odds ratio=1.85; 95% confidence interval=1.52-2.25). The results of this study confirm that SNP rs11190870 is associated with AIS.

Role of Zebrafish Lbx2 in Embryonic Lateral Line Development

BackgroundThe zebrafish ladybird homeobox homologous gene 2 (lbx2) has been suggested to play a key role in the regulation of hypaxial myogenic precursor cell migration. Unlike their lbx counterparts in mammals, the function of teleost lbx genes beyond myogenesis during embryonic development remains unexplored.Principal FindingsAbrogation of lbx2 function using a specific independent morpholino oligonucleotide (MO) or truncated lbx2 mRNA with an engrailed domain deletion (lbx2eh-) resulted in defective formation of the zebrafish posterior lateral line (PLL). Migration of the PLL primordium was altered and accompanied by increased cell death in the primordium of lbx2-MO-injected embryos. A decreased number of muscle pioneer cells and impaired expression pattern of sdf1a in the horizontal myoseptum was observed in lbx2 morphants.SignificanceInjection of lbx2 MO or lbx2eh- mRNA resulted in defective PPL formation and altered sdf1a expression, confirming an important function for lbx2 in sdf1a-dependent migration. In addition, the disassociation of PPL nerve extension with PLL primordial migration in some lbx2 morphants suggests that pathfinding of the PLL primordium and the lateral line nerve may be regulated independently.