Mechanisms of MEOX1 and MEOX2 regulation of the cyclin dependent kinase inhibitors p21 and p16 in vascular endothelial cells

Excitatory Spinal Lhx9-Derived Interneurons Modulate Locomotor Frequency in Mice

Locomotion allows us to move and interact with our surroundings. Spinal networks that control locomotion produce rhythm and left-right and flexor-extensor coordination. Several glutamatergic populations, Shox2 non-V2a, Hb9-derived interneurons, and, recently, spinocerebellar neurons have been proposed to be involved in the mouse rhythm generating networks. These cells make up only a smaller fraction of the excitatory cells in the ventral spinal cord. Here, we set out to identify additional populations of excitatory spinal neurons that may be involved in rhythm generation or other functions in the locomotor network. We use RNA sequencing from glutamatergic, non-glutamatergic, and Shox2 cells in the neonatal mice from both sexes followed by differential gene expression analyses. These analyses identified transcription factors that are highly expressed by glutamatergic spinal neurons and differentially expressed between Shox2 neurons and glutamatergic neurons. From this latter category, we identified the Lhx9-derived neurons as having a restricted spinal expression pattern with no Shox2 neuron overlap. They are purely glutamatergic and ipsilaterally projecting. Ablation of the glutamatergic transmission or acute inactivation of the neuronal activity of Lhx9-derived neurons leads to a decrease in the frequency of locomotor-like activity without change in coordination pattern. Optogenetic activation of Lhx9-derived neurons promotes locomotor-like activity and modulates the frequency of the locomotor activity. Calcium activities of Lhx9-derived neurons show strong left-right out-of-phase rhythmicity during locomotor-like activity. Our study identifies a distinct population of spinal excitatory neurons that regulates the frequency of locomotor output with a suggested role in rhythm-generation in the mouse alongside other spinal populations.

Regulatory Role of Meox1 in Muscle Growth of Sebastes schlegelii

Meox1 is a critical transcription factor that plays a pivotal role in embryogenesis and muscle development. It has been established as a marker gene for growth-specific muscle stem cells in zebrafish. In this study, we identified the SsMeox1 gene in a large teleost fish, Sebastes schlegelii. Through in situ hybridization and histological analysis, we discovered that SsMeox1 can be employed as a specific marker of growth-specific muscle stem cells, which originate from the somite stage and are primarily situated in the external cell layer (ECL) and myosepta, with a minor population distributed among muscle fibers. The knockdown of SsMeox1 resulted in a significant increase in Ccnb1 expression, subsequently promoting cell cycle progression and potentially accelerating the depletion of the stem cell pool, which ultimately led to significant growth retardation. These findings suggest that SsMeox1 arrests the cell cycle of growth-specific muscle stem cells in the G2 phase by suppressing Ccnb1 expression, which is essential for maintaining the stability of the growth-specific muscle stem cell pool. Our study provides significant insights into the molecular mechanisms underlying the indeterminate growth of large teleosts.

Identifying OGN as a Biomarker Covering Multiple Pathogenic Pathways for Diagnosing Heart Failure: From Machine Learning to Mechanism Interpretation

BACKGROUND

The pathophysiologic heterogeneity of heart failure (HF) necessitates a more detailed identification of diagnostic biomarkers that can reflect its diverse pathogenic pathways.

METHODS

We conducted weighted gene and multiscale embedded gene co-expression network analysis on differentially expressed genes obtained from HF and non-HF specimens. We employed a machine learning integration framework and protein-protein interaction network to identify diagnostic biomarkers. Additionally, we integrated gene set variation analysis, gene set enrichment analysis (GSEA), and transcription factor (TF)-target analysis to unravel the biomarker-dominant pathways. Leveraging single-sample GSEA and molecular docking, we predicted immune cells and therapeutic drugs related to biomarkers. Quantitative polymerase chain reaction validated the expressions of biomarkers in the plasma of HF patients. A two-sample Mendelian randomization analysis was implemented to investigate the causal impact of biomarkers on HF.

RESULTS

We first identified COL14A1, OGN, MFAP4, and SFRP4 as candidate biomarkers with robust diagnostic performance. We revealed that regulating biomarkers in HF pathogenesis involves TFs (BNC2, MEOX2) and pathways (cell adhesion molecules, chemokine signaling pathway, cytokine-cytokine receptor interaction, oxidative phosphorylation). Moreover, we observed the elevated infiltration of effector memory CD4+ T cells in HF, which was highly related to biomarkers and could impact immune pathways. Captopril, aldosterone antagonist, cyclopenthiazide, estradiol, tolazoline, and genistein were predicted as therapeutic drugs alleviating HF via interactions with biomarkers. In vitro study confirmed the up-regulation of OGN as a plasma biomarker of HF. Mendelian randomization analysis suggested that genetic predisposition toward higher plasma OGN promoted the risk of HF.

CONCLUSIONS

We propose OGN as a diagnostic biomarker for HF, which may advance our understanding of the diagnosis and pathogenesis of HF.

Examination of newborn DNA methylation among women with polycystic ovary syndrome/hirsutism

Research suggests that polycystic ovary syndrome (PCOS) traits (e.g., hyperandrogenism) may create a suboptimal intrauterine environment and induce epigenetic modifications. Therefore, we assessed the associations of PCOS traits with neonatal DNA methylation (DNAm) using two independent cohorts. DNAm was measured in both cohorts using the Infinium MethylationEPIC array. Multivariable robust linear regression was used to determine associations of maternal PCOS exposure or preconception testosterone with methylation β-values at each CpG probe and corrected for multiple testing by false-discovery rate (FDR). In the birth cohort, 12% (102/849) had a PCOS diagnosis (8.1% PCOS without hirsutism; 3.9% PCOS with hirsutism). Infants exposed to maternal PCOS with hirsutism compared to no PCOS had differential DNAm at cg02372539 [β(SE): -0.080 (0.010); FDR p = 0.009], cg08471713 [β(SE):0.077 (0.014); FDR p = 0.016] and cg17897916 [β(SE):0.050 (0.009); FDR p = 0.009] with adjustment for maternal characteristics including pre-pregnancy BMI. PCOS with hirsutism was also associated with 8 differentially methylated regions (DMRs). PCOS without hirsutism was not associated with individual CpGs. In an independent preconception cohort, total testosterone concentrations were associated with 3 DMRs but not with individual CpGs, though the top quartile of testosterone compared to the lowest was marginally associated with increased DNAm at cg21472377 near an uncharacterized locus (FDR p = 0.09). Examination of these probes and DMRs indicate they may be under foetal genetic control. Overall, we found several associations among newborns exposed to PCOS, specifically when hirsutism was reported, and among newborns of women with relatively higher testosterone around conception.

The role of MEOX1 in non-neoplastic and neoplastic diseases

Targeted gene therapy has shown durable efficacy in non-neoplastic and neoplastic patients. Therefore, finding a suitable target has become a key area of research. Mesenchyme homeobox 1 (MEOX1) is a transcriptional factor that plays a significant role in regulation of somite development. Evidence indicates that abnormalities in MEOX1 expression and function are associated with a variety of pathologies, including non-neoplastic and neoplastic diseases. MEOX1 expression is upregulated during progression of most diseases and plays a critical role in maintenance of the cellular phenotypes such as cell differentiation, cell cycle arrest and senescence, migration, and proliferation. Therefore, MEOX1 may become an important molecular target and therapeutic target. This review will discuss the current state of knowledge on the role of MEOX1 in different diseases.

Integrative single-cell analysis of cardiogenesis identifies developmental trajectories and non-coding mutations in congenital heart disease

To define the multi-cellular epigenomic and transcriptional landscape of cardiac cellular development, we generated single-cell chromatin accessibility maps of human fetal heart tissues. We identified eight major differentiation trajectories involving primary cardiac cell types, each associated with dynamic transcription factor (TF) activity signatures. We contrasted regulatory landscapes of iPSC-derived cardiac cell types and their in vivo counterparts, which enabled optimization of in vitro differentiation of epicardial cells. Further, we interpreted sequence based deep learning models of cell-type-resolved chromatin accessibility profiles to decipher underlying TF motif lexicons. De novo mutations predicted to affect chromatin accessibility in arterial endothelium were enriched in congenital heart disease (CHD) cases vs. controls. In vitro studies in iPSCs validated the functional impact of identified variation on the predicted developmental cell types. This work thus defines the cell-type-resolved cis-regulatory sequence determinants of heart development and identifies disruption of cell type-specific regulatory elements in CHD.

Low expression of MEOX2 is associated with poor survival in patients with breast cancer

Aim: To investigate associations of MEOX2 expression with clinicopathological features and survival of breast cancer patients. Materials & methods: We used a breast cancer tissue microarray for immunohistochemistry. Associations between MEOX2 expression and clinicopathological features were analyzed using the χ-square test. Survival analysis was determined using a Kaplan-Meier curve. Multivariate Cox regression was used to determine associations of MEOX2 expression with overall survival. Results: We found that 74.1% of patients (100/135) had expression of MEOX2 at varying levels. MEOX2 was associated with histological grade and negatively correlated with Ki67 expression. Lower MEOX2 expression was significantly associated with decreased overall survival (p = 0.0011). Conclusion: MEOX2 expression could be a novel diagnostic and prognostic biomarker of breast cancer.

Role of Sp1 in atherosclerosis

Specificity protein (Sp) is a famous family of transcription factors including Sp1, Sp2 and Sp3. Sp1 is the first one of Sp family proteins to be characterized and cloned in mammalian. It has been proposed that Sp1 acts as a modulator of the expression of target gene through interacting with a series of proteins, especially with transcriptional factors, and thereby contributes to the regulation of diverse biological processes. Notably, growing evidence indicates that Sp1 is involved in the main events in the development of atherosclerosis (AS), such as inflammation, lipid metabolism, plaque stability, vascular smooth muscle cells (VSMCs) proliferation and endothelial dysfunction. This review is designed to provide useful clues to further understanding roles of Sp1 in the pathogenesis of AS, and may be helpful for the design of novel efficacious therapeutics agents targeting Sp1.

A Novel Multi-Omics Analysis Model for Diagnosis and Survival Prediction of Lower-Grade Glioma Patients

Background

Lower-grade gliomas (LGGs) are characterized by remarkable genetic heterogeneity and different clinical outcomes. Classification of LGGs is improved by the development of molecular stratification markers including IDH mutation and 1p/19q chromosomal integrity, which are used as a hallmark of survival and therapy sensitivity of LGG patients. However, the reproducibility and sensitivity of the current classification remain ambiguous. This study aimed to construct more accurate risk-stratification approaches.

Methods

According to bioinformatics, the sequencing profiles of methylation and transcription and imaging data derived from LGG patients were analyzed and developed predictable risk score and radiomics score. Moreover, the performance of predictable models was further validated.

Results

In this study, we determined a cluster of 6 genes that were correlated with IDH mutation/1p19q co-deletion status. Risk score model was calculated based on 6 genes and showed gratifying sensitivity and specificity for survival prediction and therapy response of LGG patients. Furthermore, a radiomics risk score model was established to noninvasively assist judgment of risk score in pre-surgery. Taken together, a predictable nomogram that combined transcriptional signatures and clinical characteristics was established and validated to be preferable to the histopathological classification. Our novel multi-omics nomograms showed a satisfying performance. To establish a user-friendly application, the nomogram was further developed into a web-based platform: https://drw576223193.shinyapps.io/Nomo/, which could be used as a supporting method in addition to the current histopathological-based classification of gliomas.

Conclusions

Our novel multi-omics nomograms showed the satisfying performance of LGG patients and assisted clinicians to draw up individualized clinical management.

MEOX2-mediated regulation of Cathepsin S promotes cell proliferation and motility in glioma

Nuclear transcription factor Mesenchyme Homeobox 2 (MEOX2) is a homeobox gene that is originally discovered to suppress the growth of vascular smooth muscle and endothelial cells. However, whether or not it is connected to cancer is yet unknown. Here, we report that MEOX2 functions as a tumor-initiating element in glioma. Bioinformatic analyses of public databases and investigation of MEOX2 expression in patients with glioma demonstrated that MEOX2 was abundant at both mRNA and protein levels in glioma. MEOX2 expression was shown to be inversely linked with the prognosis of glioma patients. MEOX2 inhibition changed the morphology of glioma cells, inhibited cell proliferation and motility, whereas had no effect on cell apoptosis. Besides, silencing MEOX2 also hampered the epithelial-mesenchymal transition (EMT), focal adhesion formation, and F-actin assembly. Overexpression of MEOX2 exhibited opposite effects. Importantly, RNA-sequencing, ChIP-qPCR assay, and luciferase reporter assay revealed Cathepsin S (CTSS) as a novel transcriptional target of MEOX2 in glioma cells. Consistently, MEOX2 causes glioma tumor development in mice and greatly lowers the survival period of tumor-bearing mice. Our findings indicate that MEOX2 promotes tumorigenesis and progression of glioma partially through the regulation of CTSS. Targeting MEOX2-CTSS axis might be a promising alternative for the treatment of glioma.

Downregulation of Odd-Skipped Related 2, a Novel Regulator of Epithelial-Mesenchymal Transition, Enables Efficient Somatic Cell Reprogramming

Somatic cell reprogramming proceeds through a series of events to generate induced pluripotent stem cells (iPSCs). The early stage of reprogramming of mouse embryonic fibroblasts (MEFs) is characterized by rapid cell proliferation and morphological changes, which are accompanied by downregulation of mesenchyme-associated genes. However, the functional relevance of their downregulation to reprogramming remains poorly defined. In this study, we have screened transcriptional regulators that are downregulated immediately upon reprogramming, presumably through direct targeting by reprogramming factors. To test if these transcriptional regulators impact reprogramming when expressed continuously, we generated an expression vector that harbors human cytomegalovirus upstream open reading frame 2 (uORF2), which reduces translation to minimize the detrimental effect of an expressed protein. Screening of transcriptional regulators with this expression vector revealed that downregulation of odd-skipped related 2 (Osr2) is crucial for efficient reprogramming. Using a cell-based model for epithelial-mesenchymal transition (EMT), we show that Osr2 is a novel EMT regulator that acts through induction of TGF-β signaling. During reprogramming, Osr2 downregulation not only diminishes TGF-β signaling but also allows activation of Wnt signaling, thus promoting mesenchymal-epithelial transition (MET) toward acquisition of pluripotency. Our results illuminate the functional significance of Osr2 downregulation in erasing the mesenchymal phenotype at an early stage of somatic cell reprogramming.

Single-Cell Analysis Uncovers Osteoblast Factor Growth Differentiation Factor 10 as Mediator of Vascular Smooth Muscle Cell Phenotypic Modulation Associated with Plaque Rupture in Human Carotid Artery Disease

(1) Background: Vascular smooth muscle cells (VSMCs) undergo a complex phenotypic switch in response to atherosclerosis environmental triggers, contributing to atherosclerosis disease progression. However, the complex heterogeneity of VSMCs and how VSMC dedifferentiation affects human carotid artery disease (CAD) risk has not been clearly established. (2) Method: A single-cell RNA sequencing analysis of CD45⁻ cells derived from the atherosclerotic aorta of Apolipoprotein E-deficient (Apoe^−/−) mice on a normal cholesterol diet (NCD) or a high cholesterol diet (HCD), respecting the site-specific predisposition to atherosclerosis was performed. Growth Differentiation Factor 10 (GDF10) role in VSMCs phenotypic switch was investigated via flow cytometry, immunofluorescence in human atherosclerotic plaques. (3) Results: scRNAseq analysis revealed the transcriptomic profile of seven clusters, five of which showed disease-relevant gene signature of VSMC macrophagic calcific phenotype, VSMC mesenchymal chondrogenic phenotype, VSMC inflammatory and fibro-phenotype and VSMC inflammatory phenotype. Osteoblast factor GDF10 involved in ossification and osteoblast differentiation emerged as a hallmark of VSMCs undergoing phenotypic switch. Under hypercholesteremia, GDF10 triggered VSMC osteogenic switch in vitro. The abundance of GDF10 expressing osteogenic-like VSMCs cells was linked to the occurrence of carotid artery disease (CAD) events. (4) Conclusions: Taken together, these results provide evidence about GDF10-mediated VSMC osteogenic switch, with a likely detrimental role in atherosclerotic plaque stability.

OUP accepted manuscript

BACKGROUND

Glioblastoma (GBM) is an aggressive tumor that frequently exhibits gain of chromosome 7, loss of chromosome 10, and aberrantly activated receptor tyrosine kinase signaling pathways. Previously, we identified Mesenchyme Homeobox 2 (MEOX2), a gene located on chromosome 7, as an upregulated transcription factor in GBM. Overexpressed transcription factors can be involved in driving GBM. Here, we aimed to address the role of MEOX2 in GBM.

METHODS

Patient-derived GBM tumorspheres were used to constitutively knockdown or overexpress MEOX2 and subjected to in vitro assays including western blot to assess ERK phosphorylation. Cerebral organoid models were used to investigate the role of MEOX2 in growth initiation. Intracranial mouse implantation models were used to assess the tumorigenic potential of MEOX2. RNA-sequencing, ACT-seq, and CUT&Tag were used to identify MEOX2 target genes.

RESULTS

MEOX2 enhanced ERK signaling through a feed-forward mechanism. We identified Ser155 as a putative ERK-dependent phosphorylation site upstream of the homeobox-domain of MEOX2. S155A substitution had a major effect on MEOX2 protein levels and altered its subnuclear localization. MEOX2 overexpression cooperated with p53 and PTEN loss in cerebral organoid models of human malignant gliomas to induce cell proliferation. Using high-throughput genomics, we identified putative transcriptional target genes of MEOX2 in patient-derived GBM tumorsphere models and a fresh frozen GBM tumor.

CONCLUSIONS

We identified MEOX2 as an oncogenic transcription regulator in GBM. MEOX2 increases proliferation in cerebral organoid models of GBM and feeds into ERK signaling that represents a core signaling pathway in GBM.

Association of miR-499 Polymorphism and Its Regulatory Networks with Hashimoto Thyroiditis Susceptibility: A Population-Based Case-Control Study

Hashimoto thyroiditis (HT) is a common autoimmune disorder with a strong genetic background. Several genetic factors have been suggested, yet numerous genetic contributors remain to be fully understood in HT pathogenesis. MicroRNAs (miRs) are gene expression regulators critically involved in biological processes, of which polymorphisms can alter their function, leading to pathologic conditions, including autoimmune diseases. We examined whether miR-499 rs3746444 polymorphism is associated with susceptibility to HT in an Iranian subpopulation. Furthermore, we investigated the potential interacting regulatory network of the miR-499. This case-control study included 150 HT patients and 152 healthy subjects. Genotyping of rs3746444 was performed by the PCR-RFLP method. Also, target genomic sites of the polymorphism were predicted using bioinformatics. Our results showed that miR-499 rs3746444 was positively associated with HT risk in heterozygous (OR = 3.32, 95%CI = 2.00–5.53, p < 0.001, CT vs. TT), homozygous (OR = 2.81, 95%CI = 1.30–6.10, p = 0.014, CC vs. TT), dominant (OR = 3.22, 95%CI = 1.97–5.25, p < 0.001, CT + CC vs. TT), overdominant (OR = 2.57, 95%CI = 1.62–4.09, p < 0.001, CC + TT vs. CT), and allelic (OR = 1.92, 95%CI = 1.37–2.69, p < 0.001, C vs. T) models. Mapping predicted target genes of miR-499 on tissue-specific-, co-expression-, and miR-TF networks indicated that main hub-driver nodes are implicated in regulating immune system functions, including immunorecognition and complement activity. We demonstrated that miR-499 rs3746444 is linked to HT susceptibility in our population. However, predicted regulatory networks revealed that this polymorphism is contributing to the regulation of immune system pathways.

Exosomal circular RNA circ_0074673 regulates the proliferation, migration, and angiogenesis of human umbilical vein endothelial cells via the microRNA-1200/MEOX2 axis

Circular RNAs (circRNAs) are implicated in the pathogenesis of gestational diabetes mellitus (GDM). The aim of this study was to investigate the roles and molecular mechanism underlying the effects of circ_0074673 in GDM. Exosomal morphology was visualized by transmission electron microscopy (TEM), while exosomal size and concentration were determined by nanoparticle tracking analysis (NTA). The expression of CD9 and CD63 was measured by western blotting. The levels of circ_0074673, miR-1200 and mesenchyme homeobox 2 (MEOX2) were determined by quantitative real-time polymerase chain reaction (qPCR). Cellular proliferation, migration, and angiogenesis were measured by Cell Counting Kit-8 (CCK-8), transwell, and tube formation assays, respectively. The binding relationship between circ_0074673 or MEOX2 and miR-1200 was evaluated by luciferase reporter assay, RNA-binding protein immunoprecipitation (RIP) assay and RNA-pull-down assay. The results showed that exosomal size and concentration were greater in the umbilical cord blood of patients with GDM than in that of the healthy controls. The expression of circ_0074673 was upregulated in exosomes from GDM and in human umbilical vein endothelial cells (HUVECs) co-cultured with exosomes. High glucose (HG) treatment suppressed cellular proliferation, migration, and angiogenesis. Circ_0074673 knockdown enhanced the proliferation, migration, and angiogenesis of HG treated HUVECs (HG-HUVECs). As circ_0074673 and MEOX2 directly bind to miR-1200, circ_0074673 silencing promoted the biological functions of HG-HUVECs by sponging miR-1200 and further targeting MEOX2. Altogether, the loss of exosomal circ_0074673 facilitated the proliferation, migration, and angiogenesis of HG-HUVECs via the miR-1200/MEOX2 axis, suggesting that circ_0074673 is a potential therapeutic target for GDM.

Spatio-temporal model of Meox1 expression control involvement of Sca-1-positive stem cells in neointima formation through the synergistic effect of Rho/CDC42 and SDF-1α/CXCR4

AIMS

Neointimal hyperplasia remains a major obstacle in vascular regeneration. Sca-1-positive progenitor cells residing within the vascular adventitia play a crucial role in the assemblage of vascular smooth muscle cell (VSMC) and the formation of the intimal lesion. However, the underlying mechanisms during vascular injury are still unknown.

METHODS AND RESULTS

Aneointimal formation rat model was prepared by carotid artery injury using 2F-Forgaty. After vascular injury, Meox1 expressions time-dependently increased during the neointima formation, with its levels concurrently increasing in the adventitia, media, and neointima. Meox1 was highly expressed in the adventitia on the first day after vascular injury compared to the expression levels in the media. Conversely, by the 14th day post-injury, Meox1 was extensively expressed more in the media and neointima than the adventitia. Analogous to the change of Meox1 in injured artery, Sca-1+ progenitor cells increased in the adventitia wall in a time-dependent manner and reached peak levels on the 7th day after injury. More importantly, this effect was abolished by Meox1 knockdown with shRNA. The enhanced expression of SDF-1α after vascular injury was associated with the markedly enhanced expression levels of Sca1+ progenitor cell, and these levels were relatively synchronously increased within neointima by the 7th day after vascular injury. These special effects were abolished by the knockdown of Meox1 with shRNA and inhibition of CXCR4 by its inhibitor, AMD3100. Finally, Meox1 concurrently regulated SDF-1α expressions in VSMC via activating CDC42, and CDC42 inhibition abolished these effects by its inhibitor, ZCL278. Also, Meox1 was involved in activation of the CXCR4 expression of Sca-1+ progenitor cells by CDC42.

CONCLUSIONS

Spatio-temporal model of Meox1 expression regulates theSca-1+progenitor cell migration during the formation of the neointima through the synergistic effect of Rho/CDC42 and SDF-1α/CXCR4.

Epigenetic landscapes of intracranial aneurysm risk haplotypes implicate enhancer function of endothelial cells and fibroblasts in dysregulated gene expression

BACKGROUND

Genome-wide association studies have identified many single nucleotide polymorphisms (SNPs) associated with increased risk for intracranial aneurysm (IA). However, how such variants affect gene expression within IA is poorly understood. We used publicly-available ChIP-Seq data to study chromatin landscapes surrounding risk loci to determine whether IA-associated SNPs affect functional elements that regulate gene expression in cell types comprising IA tissue.

METHODS

We mapped 16 significant IA-associated SNPs to linkage disequilibrium (LD) blocks within human genome. Using ChIP-Seq data, we examined these regions for presence of H3K4me1, H3K27ac, and H3K9ac histone marks (typically associated with latent/active enhancers). This analysis was conducted in several cell types that are present in IA tissue (endothelial cells, smooth muscle cells, fibroblasts, macrophages, monocytes, neutrophils, T cells, B cells, NK cells). In cell types with significant histone enrichment, we used HiC data to investigate topologically associated domains (TADs) encompassing the LD blocks to identify genes that may be affected by IA-associated variants. Bioinformatics were performed to determine the biological significance of these genes. Genes within HiC-defined TADs were also compared to differentially expressed genes from RNA-seq/microarray studies of IA tissues.

RESULTS

We found that endothelial cells and fibroblasts, rather than smooth muscle or immune cells, have significant enrichment for enhancer marks on IA risk haplotypes (p < 0.05). Bioinformatics demonstrated that genes within TADs subsuming these regions are associated with structural extracellular matrix components and enzymatic activity. The majority of histone marked TADs (83% fibroblasts [IMR90], 77% HUVEC) encompassed at least one differentially expressed gene from IA tissue studies.

CONCLUSIONS

These findings provide evidence that genetic variants associated with IA risk act on endothelial cells and fibroblasts. There is strong circumstantial evidence that this may be mediated through altered enhancer function, as genes in TADs encompassing enhancer marks have also been shown to be differentially expressed in IA tissue. These genes are largely related to organization and regulation of the extracellular matrix. This study builds upon our previous (Poppenberg et al., BMC Med Genomics, 2019) by including a more diverse set of data from additional cell types and by identifying potential affected genes (i.e. those in TADs).

Facilitation of Bone Healing Processes Based on the Developmental Function of Meox2 in Tooth Loss Lesion

In the present study, we examined the bone healing capacity of Meox2, a homeobox gene that plays essential roles in the differentiation of a range of developing tissues, and identified its putative function in palatogenesis. We applied the knocking down of Meox2 in human periodontal ligament fibroblasts to examine the osteogenic potential of Meox2. Additionally, we applied in vivo periodontitis induced experiment to reveal the possible application of Meox2 knockdown for 1 and 2 weeks in bone healing processes. We examined the detailed histomorphological changes using Masson’s trichrome staining and micro-computed tomography evaluation. Moreover, we observed the localization patterns of various signaling molecules, including α-SMA, CK14, IL-1β, and MPO to examine the altered bone healing processes. Furthermore, we investigated the process of bone formation using immunohistochemistry of Osteocalcin and Runx2. On the basis of the results, we suggest that the knocking down of Meox2 via the activation of osteoblast and modulation of inflammation would be a plausible answer for bone regeneration as a gene therapy. Additionally, we propose that the purpose-dependent selection and application of developmental regulation genes are important for the functional regeneration of specific tissues and organs, where the pathological condition of tooth loss lesion would be.

Considerations for feature selection using gene pairs and applications in large-scale dataset integration, novel oncogene discovery, and interpretable cancer screening

Background

Advancements in transcriptomic profiling have led to the emergence of new challenges regarding data integration and interpretability. Variability between measurement platforms makes it difficult to compare between cohorts, and large numbers of gene features have encouraged the use black box methods that are not easily translated into biologically and clinically meaningful findings. We propose that gene rankings and algorithms that rely on relative expression within gene pairs can address such obstacles.

Methods

We implemented an innovative process to evaluate the performance of five feature selection methods on simulated gene-pair data. Along with TSP, we consider other methods that retain more information in their score calculations, including the magnitude of gene expression change as well as within-class variation. Tree-based rule extraction was also applied to serum microRNA (miRNA) pairs in order to devise a noninvasive screening tool for pancreatic and ovarian cancer.

Results

Gene pair data were simulated using different types of signal and noise. Pairs were filtered using feature selection approaches, including top-scoring pairs (TSP), absolute differences between gene ranks, and Fisher scores. Methods that retain more information, such as the magnitude of expression change and within-class variance, yielded higher classification accuracy using a random forest model. We then demonstrate two powerful applications of gene pairs by first performing large-scale integration of 52 breast cancer datasets consisting of 10,350 patients. Not only did we confirm known oncogenes, but we also propose novel tumorigenic genes, such as BSDC1 and U2AF1, that could distinguish between tumor subtypes. Finally, circulating miRNA pairs were filtered and salient rules were extracted to build simplified tree ensemble learners (STELs) for four types of cancer. These accessible clinical frameworks detected pancreatic and ovarian cancer with 84.8 and 93.6% accuracy, respectively.

Conclusion

Rank-based gene pair classification benefits from careful feature selection methods that preserve maximal information. Gene pairs enable dataset integration for greater statistical power and discovery of robust biomarkers as well as facilitate construction of user-friendly clinical screening tools.

Single-Cell Transcriptome Analysis Reveals Six Subpopulations Reflecting Distinct Cellular Fates in Senescent Mouse Embryonic Fibroblasts

Replicative senescence is a hallmark of aging, which also contributes to individual aging. Mouse embryonic fibroblasts (MEFs) provide a convenient replicative senescence model. However, the heterogeneity of single MEFs during cellular senescence has remained unclear. Here, we conducted single-cell RNA sequencing on senescent MEFs. Principal component analysis showed obvious heterogeneity among these MEFs such that they could be divided into six subpopulations. Three types of gene expression analysis revealed distinct expression features of these six subpopulations. Trajectory analysis revealed three distinct lineages during MEF senescence. In the main lineage, some senescence-associated secretory phenotypes were upregulated in a subset of cells from senescent clusters, which could not be distinguished in a previous bulk study. In the other two lineages, a possibility of escape from cell cycle arrest and coupling between translation-related genes and ATP synthesis-related genes were also discovered. Additionally, we found co-expression of transcription factor HOXD8 coding gene and its potential target genes in the main lineage. Overexpression of Hoxd8 led to senescence-associated phenotypes, suggesting HOXD8 is a new regulator of MEF senescence. Together, our single-cell sequencing on senescent MEFs largely expanded the knowledge of a basic cell model for aging research.

Microarray analysis of genes from animals treated with a traditional formulation ChandraprabhaVati reveals its therapeutic targets

Background

Traditional medicinal preparations have not received global acceptance, and their therapeutic benefits remain disputed due to lack of scientific evidence on their mechanism of action. Microarray analysis has emerged as a powerful technique that can aid in understanding the complex signaling networks activated by these formulations and thereby assess their beneficial as well as adverse effects.

Aim

The present work aims to investigate the differential influence of ChandraprabhaVati, Ayurvedic formulation used in the treatment of diabetes, anemia, urinary, respiratory, skin and liver disorders.

Materials and methods

The RNA from the liver of rats treated with different doses of ChandraprabhaVati for 28 days was isolated and studied for the genome-wide changes in the expression.

Results

The results revealed several molecular targets that could contribute to the therapeutic effects of ChandraprabhaVati. Several genes have been differentially expressed, among those miRNAs miR-434, miR877, and miRlet7e contribute to the anti-diabetic, anti-fibrotic and anti-inflammatory of CPV. The rejuvenative activity of CPV may be due to the MeOX1 and Upf3b genes. Up-regulation of Hbaa2 gene facilitates the anti-anemic effect. Interestingly gender-specific differential expressions of genes were also observed. Rab3d were found to be altered in female when compared to male animals.

Conclusion

Thus the microarray data for the CPV treated animals has revealed molecular targets that may be responsible for the various known therapeutic effects and also identified new beneficial effects of CPV.

Prognostic significance of MEOX2 in gliomas

Gliomas are the most common malignant primary tumors in the central nervous system and have variable predictive clinical courses. Glioblastoma, the most aggressive form of glioma, is a complex disease with unsatisfactory therapeutic solutions and a very poor prognosis. Some processes at stake in gliomagenesis have been discovered but little is known about the role of homeobox genes, even though they are highly expressed in gliomas, particularly in glioblastoma. Among them, the transcription factor Mesenchyme Homeobox 2 (MEOX2) had previously been associated with malignant progression and clinical prognosis in lung cancer and hepatocarcinoma but never studied in glioma. The aim of our study was to investigate the clinical significance of MEOX2 in gliomas. We assessed the expression of MEOX2 according to IDH1/2 molecular profile and patient survival among three different public datasets: The Cancer Genome Atlas (TCGA), The Chinese Glioma Genome Atlas (CGGA) and the US National Cancer Institute Repository for Molecular Brain Neoplasia Data (Rembrandt). We then evaluated the prognostic significance of MEOX2 protein expression on 112 glioma clinical samples including; 56 IDH1 wildtype glioblastomas, 7 IDH1 wild-type lower grade gliomas, 49 IDH1 mutated lower grade gliomas. Survival rates were estimated by the Kaplan-Meier method followed by uni/multivariate analyses. We demonstrated that MEOX2 was one of the transcription factors most closely associated with overall survival in glioma. Moreover, MEOX2 expression was associated with IDH1/2 wildtype molecular subtype and was significantly correlated with overall survival of all gliomas and, more interestingly, in lower grade glioma. To conclude, our results may be the first to provide insight into the clinical significance of MEOX2 in gliomas, which is a factor closely related to patient outcome. MEOX2 could constitute an interesting prognostic biomarker, especially for lower grade glioma.

Homeobox Genes and Homeodomain Proteins: New Insights into Cardiac Development, Degeneration and Regeneration

Cardiovascular diseases are the most common cause of human death in the developing world. Extensive evidence indicates that various toxic environmental factors and unhealthy lifestyle choices contribute to the risk, incidence and severity of cardiovascular diseases. Alterations in the genetic level of myocardium affects normal heart development and initiates pathological processes leading to various types of cardiac diseases. Homeobox genes are a large and highly specialized family of closely related genes that direct the formation of body structure, including cardiac development. Homeobox genes encode homeodomain proteins that function as transcription factors with characteristic structures that allow them to bind to DNA, regulate gene expression and subsequently control the proper physiological function of cells, tissues and organs. Mutations in homeobox genes are rare and usually lethal with evident alterations in cardiac function at or soon after the birth. Our understanding of homeobox gene family expression and function has expanded significantly during the recent years. However, the involvement of homeobox genes in the development of human and animal cardiac tissue requires further investigation. The phenotype of human congenital heart defects unveils only some aspects of human heart development. Therefore, mouse models are often used to gain a better understanding of human heart function, pathology and regeneration. In this review, we have focused on the role of homeobox genes in the development and pathology of human heart as potential tools for the future development of targeted regenerative strategies for various heart malfunctions.

Association of MEOX2 polymorphism with nonsyndromic cleft palate only in a Vietnamese population

To evaluate the association between the single nucleotide polymorphism (SNP) rs227493 in the MEOX2 gene and nonsyndromic cleft palate only, this research was conducted as a case-control study by comparing a nonsyndromic cleft palate only group with an independent, healthy, and unaffected control group who were both examined by specialists. Based on clinical examination and medical records, we analyzed a total of 570 DNA samples, including 277 cases and 293 controls, which were extracted from dry blood spot samples collected from both the Odonto and Maxillofacial Hospital in Ho Chi Minh City and Nguyen Dinh Chieu Hospital in Ben Tre province, respectively. The standard procedures of genotyping the specific SNP (rs2237493) for MEOX2 were performed on a StepOne Realtime PCR system with TaqMan SNP Genotyping Assays. Significant statistical differences were observed in allelic frequencies (allele T and allele G) between the non-syndromic cleft palate only and control groups in female subjects, with an allelic odds ratio of 1.455 (95% confidence interval: 1.026-2.064) and P < 0.05. These study findings suggest that nonsyndromic isolated cleft palate might be influenced by variation of MEOX2, especially SNP rs2237493 in Vietnamese females.

The Role of microRNAs in Embryonic and Induced Pluripotency

Research on stem cells is one of the fastest growing areas of regenerative medicine that paves the way for a comprehensive solution to cell therapy. Today, stem cells are precious assets for generating different types of cells derived from either natural embryonic stem (ES) cells or induced pluripotent stem (iPS) cells. The iPS technology can revolutionize the future of clinics by offering personalized medicine, which will provide the future treatment for curing untreatable diseases. Although iPS cell therapy is now at its infancy, promising research has motivated scientists to pursue this therapeutic approach. In this article, we provide information regarding similarities and differences between ES and iPS cells, and focus on the non-integrating methods of iPS generation via RNA molecules, especially microRNAs with an emphasis on the elucidation of their role and importance in pluripotency.

Mesenchyme homeobox 1 mediates transforming growth factor-β (TGF-β)-induced smooth muscle cell differentiation from mouse mesenchymal progenitors

Differentiation of smooth muscle cells (SMCs) is critical for proper vasculogenesis and angiogenesis. However, the molecular mechanisms controlling SMC differentiation are not completely understood. During embryogenesis, the transcription factor mesenchyme homeobox 1 (Meox1) is expressed in the early developing somite, which is one of the origins of SMCs. In the present study, we identified Meox1 as a positive regulator of SMC differentiation. We found that transforming growth factor-β (TGF-β) induces Meox1 expression in the initial phase of SMC differentiation of pluripotent murine C3H10T1/2 cells. shRNA-mediated Meox1 knockdown suppressed TGF-β-induced expression of SMC early markers, whereas Meox1 overexpression increased expression of these markers. Mechanistically, Meox1 promoted SMAD family member 3 (Smad3) nuclear retention during the early stage of TGF-β stimulation because Meox1 inhibited protein phosphatase Mg²⁺/Mn²⁺-dependent 1A (PPM1A) and thereby prevented PPM1A-mediated Smad3 dephosphorylation. Meox1 appears to promote PPM1A degradation, leading to sustained Smad3 phosphorylation, thus allowing Smad3 to stimulate SMC gene transcription. In vivo, Meox1 knockdown in mouse embryos impaired SMC marker expression in the descending aorta of neonatal mice, indicating that Meox1 is essential for SMC differentiation during embryonic development. In summary, the transcriptional regulator Meox1 controls TGF-β-induced SMC differentiation from mesenchymal progenitor cells by preventing PPM1A-mediated Smad3 dephosphorylation, thereby supporting SMC gene expression.

Loss of heterogeneity, quiescence, and differentiation in muscle stem cells

Skeletal muscle stem cells in the adult display heterogeneity that has been functionally linked to their behavior, self-renewal capacity, and resistance to stress in hostile environments. Behavioral heterogeneity emerges also during developmental myogenesis. Muscle stem cell diversity may be functionally linked to the changing needs of skeletal muscle regeneration. Intriguingly, dramatic reduction of stem cell diversity, the "clonal drift", that implies loss of stem cells and related expansion of clonally related stem cells has been reported for tissue replacement in several adult tissues and suggested in the zebrafish embryo. A recent study shows clonal drift of muscle stem cells in the zebrafish embryo caused by inhibition of the cell cycle and directed by the homeobox protein Meox1. Although stem cell quiescence is associated with inhibition of the transition phase G0/G1 of the cell cycle, Meox1 triggers the muscle stem cell fate by an arrest in G2 phase. Why efficient muscle growth in the zebrafish embryo requires sacrificing stem cell heterogeneity in favor of a small number of dominant clones has not been elucidated. The significance of G2-halted stem cells, which are generally associated with robust regeneration capacity, is also intriguing. These processes are relevant for understanding organ growth and the mechanisms that govern stem cell quiescence.

Vascular senescence and ageing: a role for the MEOX proteins in promoting endothelial dysfunction

In the vascular system, ageing is accompanied by the accrual of senescent cells and is associated with an increased risk of vascular disease. Endothelial cell (EC) dysfunction is a hallmark of vascular disease and is characterized by decreased angiogenic potential, reduced nitric oxide bioavailability, impaired vasodilation, increased production of ROS, and enhanced inflammation. In ECs, the major producer of nitric oxide is the endothelial nitric oxide synthase (eNOS) enzyme that is encoded by the NOS3 gene. NOS3/eNOS function is tightly regulated at both the transcriptional and post-transcriptional levels to maintain normal vascular function. A key transcriptional regulator of eNOS expression is p53, which has been shown to play a central role in mediating cellular senescence and thereby vascular dysfunction. Herein, we show that, in ECs, the MEOX homeodomain transcription factors decrease the expression of genes involved in angiogenesis, repress eNOS expression at the mRNA and protein levels, and increase the expression of p53. These findings support a role for the MEOX proteins in promoting endothelial dysfunction.

Mesenchyme Homeobox 2 Enhances Migration of Endothelial Colony Forming Cells Exposed to Intrauterine Diabetes Mellitus

Diabetes mellitus (DM) during pregnancy has long-lasting implications for the fetus, including cardiovascular morbidity. Previously, we showed that endothelial colony forming cells (ECFCs) from DM human pregnancies have decreased vasculogenic potential. Here, we evaluate whether the molecular mechanism responsible for this phenotype involves the transcription factor, Mesenchyme Homeobox 2 (MEOX2). In human umbilical vein endothelial cells, MEOX2 upregulates cyclin-dependent kinase inhibitor expression, resulting in increased senescence and decreased proliferation. We hypothesized that dysregulated MEOX2 expression in neonatal ECFCs from DM pregnancies decreases network formation through increased senescence and altered cell cycle progression. Our studies show that nuclear MEOX2 is increased in ECFCs from DM pregnancies. To determine if MEOX2 is sufficient and/or required to induce impaired network formation, MEOX2 was overexpressed and depleted in ECFCs from control and DM pregnancies, respectively. Surprisingly, MEOX2 overexpression in control ECFCs resulted in increased network formation, altered cell cycle progression, and increased senescence. In contrast, MEOX2 knockdown in ECFCs from DM pregnancies led to decreased network formation, while cell cycle progression and senescence were unaffected. Importantly, migration studies demonstrated that MEOX2 overexpression increased migration, while MEOX2 knockdown decreased migration. Taken together, these data suggest that altered migration may be mediating the impaired vasculogenesis of ECFCs from DM pregnancies. While initially believed to be maladaptive, these data suggest that MEOX2 may serve a protective role, enabling increased vessel formation despite exposure to a DM intrauterine environment. J. Cell. Physiol. 232: 1885-1892, 2017. © 2016 Wiley Periodicals, Inc.

Master regulators in primary skin fibroblast fate reprogramming in a human ex vivo model of chronic wounds

Fibroblasts are important players in regulating tissue homeostasis. In the dermis, they are involved in wound healing where they differentiate into contractile myofibroblasts leading to wound closure. In nonhealing chronic wounds, fibroblasts fail to undertake differentiation. We established and used a human ex vivo model of chronic wounds where fibroblasts can undergo normal myofibroblast differentiation, or take on a nondifferentiable pathological state. At the whole genome scale, we identified the genes that are differentially regulated in these two cell fates. By coupling the search of evolutionary conserved regulatory elements with global gene network expression changes, we identified transcription factors (TF) potentially involved in myofibroblast differentiation, and constructed a network of relationship between these key factors. Among these, we found that TCF4, SOX9, EGR2, and FOXS1 are major regulators of fibroblast to myofibroblast differentiation. Conversely, down-regulation of MEOX2, SIX2, and MAF causes reprogramming of fibroblasts to myofibroblasts even in absence of TGF-β, the natural inducer of myofibroblast differentiation. These results provide insight into the fibroblast differentiation program and reveal a TF network essential for cellular reprogramming. They could lead to the development of new therapeutics to treat fibroblast-related human pathologies.

Overexpression of MEOX2 and TWIST1 is associated with H3K27me3 levels and determines lung cancer chemoresistance and prognosis

Lung cancer is the leading cause of death from malignant diseases worldwide, with the non-small cell (NSCLC) subtype accounting for the majority of cases. NSCLC is characterized by frequent genomic imbalances and copy number variations (CNVs), but the epigenetic aberrations that are associated with clinical prognosis and therapeutic failure remain not completely identify. In the present study, a total of 55 lung cancer patients were included and we conducted genomic and genetic expression analyses, immunohistochemical protein detection, DNA methylation and chromatin immunoprecipitation assays to obtain genetic and epigenetic profiles associated to prognosis and chemoresponse of NSCLC patients. Finally, siRNA transfection-mediated genetic silencing and cisplatinum cellular cytotoxicity assays in NSCLC cell lines A-427 and INER-37 were assessed to describe chemoresistance mechanisms involved. Our results identified high frequencies of CNVs (66–51% of cases) in the 7p22.3–p21.1 and 7p15.3–p15.2 cytogenetic regions. However, overexpression of genes, such as MEOX2, HDAC9, TWIST1 and AhR, at 7p21.2–p21.1 locus occurred despite the absence of CNVs and little changes in DNA methylation. In contrast, the promoter sequences of MEOX2 and TWIST1 displayed significantly lower/decrease in the repressive histone mark H3K27me3 and increased in the active histone mark H3K4me3 levels. Finally these results correlate with poor survival in NSCLC patients and cellular chemoresistance to oncologic drugs in NSCLC cell lines in a MEOX2 and TWIST1 overexpression dependent-manner. In conclusion, we report for the first time that MEOX2 participates in chemoresistance irrespective of high CNV, but it is significantly dependent upon H3K27me3 enrichment probably associated with aggressiveness and chemotherapy failure in NSCLC patients, however additional clinical studies must be performed to confirm our findings as new probable clinical markers in NSCLC patients.

Altered expression of genes associated with telomere maintenance and cell function of human vascular endothelial cell at elevated temperature

The pathophysiological alterations of vascular endothelial cells induced by heat were studied. Human umbilical venous endothelial cells were cultured for 1 day at three different temperatures (37, 39, and 42 °C). The telomere lengths, the expressions of proteins associated with telomere length maintenance, apoptosis, heat shock, and vascular function were analyzed. The cell growth was not suppressed at 39 °C but suppressed at 42 °C. The mean telomere length did not change, whereas the telomere length distribution altered at 42 °C. Long telomere decreased and middle-sized telomere increased in the telomere length distribution at 42 °C. The telomerase activity did not show any heat-associated alterations. However, of the components of telomerase, telomerase reverse transcriptase was up-regulated along temperature elevation. In contrast, the expression level of RNA component TERC did not altered. Among the analyzed apoptosis-associated proteins, p21 was down-regulated and phosphorylated p53 was up-regulated. Heat shock proteins and NO synthase were up-regulated at 42 °C. These results suggested that induced growth suppression or cell senescence was induced by strong heat stress rather than mild one predominantly in cells bearing long telomeres with p53 activation, and simultaneously activated some telomere-associated factors, heat shock proteins, and NO synthesis probably for heat-resistant cell survival.

Epstein-Barr virus nuclear antigen 3A protein regulates CDKN2B transcription via interaction with MIZ-1

The Epstein-Barr virus (EBV) nuclear antigen 3 family of protein is critical for the EBV-induced primary B-cell growth transformation process. Using a yeast two-hybrid screen we identified 22 novel cellular partners of the EBNA3s. Most importantly, among the newly identified partners, five are known to play direct and important roles in transcriptional regulation. Of these, the Myc-interacting zinc finger protein-1 (MIZ-1) is a transcription factor initially characterized as a binding partner of MYC. MIZ-1 activates the transcription of a number of target genes including the cell cycle inhibitor CDKN2B. Focusing on the EBNA3A/MIZ-1 interaction we demonstrate that binding occurs in EBV-infected cells expressing both proteins at endogenous physiological levels and that in the presence of EBNA3A, a significant fraction of MIZ-1 translocates from the cytoplasm to the nucleus. Moreover, we show that a trimeric complex composed of a MIZ-1 recognition DNA element, MIZ-1 and EBNA3A can be formed, and that interaction of MIZ-1 with nucleophosmin (NPM), one of its coactivator, is prevented by EBNA3A. Finally, we show that, in the presence of EBNA3A, expression of the MIZ-1 target gene, CDKN2B, is downregulated and repressive H3K27 marks are established on its promoter region suggesting that EBNA3A directly counteracts the growth inhibitory action of MIZ-1.

Notchless is required for axial skeleton formation in mice

Maintenance of cell survival is essential for proper embryonic development. In the mouse, Notchless homolog 1 (Drosophila) (Nle1) is instrumental for survival of cells of the inner cell mass upon implantation. Here, we analyze the function of Nle1 after implantation using the Meox2^tm1(cre)Sor mouse that expresses the Cre recombinase specifically in the epiblast at E5.5. First, we find that NLE1 function is required in epiblast cells, as Nle1-deficient cells are rapidly eliminated. In this report, we also show that the Meox2^Cre transgene is active in specific tissues during organogenesis. In particular, we detect high Cre expression in the vertebral column, ribs, limbs and tailbud. We took advantage of this dynamic expression profile to analyze the effects of inducing mosaic deletion of Nle1 in the embryo. We show that Nle1 deletion in this context, results in severe developmental anomalies leading to lethality at birth. Mutant embryos display multiple developmental defects in particular during axial skeletal formation. We also provide evidence that axial defects are due to an increase in apoptotic cell death in the somite at E9.5. These data demonstrate an essential role for Nle1 during organogenesis and in particular during axial development.

Stimulation of the proliferation of human normal esophageal epithelial cells by fumonisin B1 and its mechanism

Previous epidemiological studies have demonstrated a correlation between fumonisin B₁ (FB₁) and human esophageal cancer in China, Iran and South Africa. The purpose of this study was to investigate the effects of FB₁ on the proliferation, cell-cycle and apoptosis of normal human esophageal epithelial cells (HEECs) and to explore the molecular mechanisms of these effects. The proliferation of HEECs treated with FB₁ was assessed using a colorimetric assay, while analyses of the cell cycle and apoptosis were performed using flow cytometry and the measurement of the protein expressions of genes associated with the cell cycle was conducted using western blotting. The results showed that FB₁ stimulated the proliferation of HEECs, decreased the percentage of cells in the G0/G1 phase and reduced apoptosis. The western blotting results showed that FB₁ significantly increased the protein expression of cyclin D1 and significantly decreased the protein expression of cyclin E, p21 and p27. The results indicated that FB₁ stimulated the proliferation of HEECs by affecting the cell cycle and apoptosis. This mechanism was associated with changes in cyclin D1, cyclin E, p21 and p27 expression.

The Ski-Zeb2-Meox2 pathway provides a novel mechanism for regulation of the cardiac myofibroblast phenotype

Cardiac fibrosis is linked to fibroblast-to-myofibroblast phenoconversion and proliferation but the mechanisms underlying this are poorly understood. Ski is a negative regulator of TGF-β-Smad signaling in myofibroblasts, and might redirect the myofibroblast phenotype back to fibroblasts. Meox2 could alter TGF-β-mediated cellular processes and is repressed by Zeb2. Here, we investigated whether Ski diminishes the myofibroblast phenotype by de-repressing Meox2 expression and function through repression of Zeb2 expression. We show that expression of Meox1 and Meox2 mRNA and Meox2 protein is reduced during phenoconversion of fibroblasts to myofibroblasts. Overexpression of Meox2 shifts the myofibroblasts into fibroblasts, whereas the Meox2 DNA-binding mutant has no effect on myofibroblast phenotype. Overexpression of Ski partially restores Meox2 mRNA expression levels to those in cardiac fibroblasts. Expression of Zeb2 increased during phenoconversion and Ski overexpression reduces Zeb2 expression in first-passage myofibroblasts. Furthermore, expression of Meox2 is decreased in scar following myocardial infarction, whereas Zeb2 protein expression increases in the infarct scar. Thus Ski modulates the cardiac myofibroblast phenotype and function through suppression of Zeb2 by upregulating the expression of Meox2. This cascade might regulate cardiac myofibroblast phenotype and presents therapeutic options for treatment of cardiac fibrosis.

The molecular balancing act of p16(INK4a) in cancer and aging

p16(INK4a), located on chromosome 9p21.3, is lost among a cluster of neighboring tumor suppressor genes. Although it is classically known for its capacity to inhibit cyclin-dependent kinase (CDK) activity, p16(INK4a) is not just a one-trick pony. Long-term p16(INK4a) expression pushes cells to enter senescence, an irreversible cell-cycle arrest that precludes the growth of would-be cancer cells but also contributes to cellular aging. Importantly, loss of p16(INK4a) is one of the most frequent events in human tumors and allows precancerous lesions to bypass senescence. Therefore, precise regulation of p16(INK4a) is essential to tissue homeostasis, maintaining a coordinated balance between tumor suppression and aging. This review outlines the molecular pathways critical for proper p16(INK4a) regulation and emphasizes the indispensable functions of p16(INK4a) in cancer, aging, and human physiology that make this gene special.

Mutation in MEOX1 gene causes a recessive Klippel-Feil syndrome subtype

Background

Klippel-Feil syndrome (KFS) is characterized by the developmental failure of the cervical spine and has two dominantly inherited subtypes. Affected individuals who are the children of a consanguineous marriage are extremely rare in the medical literature, but the gene responsible for this recessive trait subtype of KFS has recently been reported.

Results

We identified a family with the KFS phenotype in which their parents have a consanguineous marriage. Radiological examinations revealed that they carry fusion defects and numerical abnormalities in the cervical spine, scoliosis, malformations of the cranial base, and Sprengel’s deformity. We applied whole genome linkage and whole-exome sequencing analysis to identify the chromosomal locus and gene mutated in this family. Whole genome linkage analysis revealed a significant linkage to chromosome 17q12-q33 with a LOD score of 4.2. Exome sequencing identified the G > A p.Q84X mutation in the MEOX1 gene, which is segregated based on pedigree status. Homozygous MEOX1 mutations have reportedly caused a similar phenotype in knockout mice.

Conclusions

Here, we report a truncating mutation in the MEOX1 gene in a KFS family with an autosomal recessive trait. Together with another recently reported study and the knockout mouse model, our results suggest that mutations in MEOX1 cause a recessive KFS phenotype in humans.

MicroRNA-mediated epigenetic silencing of sirtuin1 contributes to impaired angiogenic responses

RATIONALE

Transforming growth factor (TGF)-β was linked to abnormal vessel function and can mediate impairment of endothelial angiogenic responses. Its effect on microRNAs and downstream targets in this context is not known.

OBJECTIVE

To study the role of microRNAs in TGF-β-mediated angiogenic activity.

METHODS AND RESULTS

MicroRNA profiling after TGF-β treatment of endothelial cells identified miR-30a-3p, along with other members of the miR-30 family, to be strongly silenced. Supplementation of miR-30a-3p restored function in TGF-β-treated endothelial cells. We identified the epigenetic factor methyl-CpG-binding protein 2 (MeCP2) to be a direct and functional target of miR-30a-3p. Viral overexpression of MeCP2 mimicked the effects of TGF-β, suggesting that derepression of MeCP2 after TGF-β treatment may be responsible for impaired angiogenic responses. Silencing of MeCP2 rescued detrimental TGF-β effects on endothelial cells. Microarray transcriptome analysis of MeCP2-overexpressing endothelial cells identified several deregulated genes important for endothelial cell function including sirtuin1 (Sirt1). In vivo experiments using endothelial cell-specific MeCP2 null or Sirt1 transgenic mice confirmed the involvement of MeCP2/Sirt1 in the regulation of angiogenic functions of endothelial cells. Additional experiments identified that MeCP2 inhibited endothelial angiogenic characteristics partly by epigenetic silencing of Sirt1.

CONCLUSIONS

TGF-β impairs endothelial angiogenic responses partly by downregulating miR-30a-3p and subsequent derepression of MeCP2-mediated epigenetic silencing of Sirt1.

The dual roles of homeobox genes in vascularization and wound healing

Homeobox genes represent a family of highly conserved transcription factors originally discovered to regulate organ patterning during development. More recently, several homeobox genes were shown to affect processes in adult tissue, including angiogenesis and wound healing. Whereas a subset of members of the Hox-family of homeobox genes activate growth and migration to promote angiogenesis or wound healing, other Hox genes function to restore or maintain quiescent, differentiated tissue function. Pathological tissue remodeling is linked to differential expression of activating or stabilizing Hox genes and dysregulation of Hox expression can contribute to disease progression. Studies aimed at understanding the role and regulation of Hox genes have provided insight into how these potent morphoregulatory genes can be applied to enhance tissue engineering or limit cancer progression.