Role of homeobox genes in the patterning, specification, and differentiation of ectodermal appendages in mammals

Lithium response in bipolar disorder: Epigenome-wide DNA methylation signatures and epigenetic aging

Lithium (Li) is the first-line treatment for bipolar disorder (BD) even though only 30 % of BD patients are considered excellent responders. The mechanisms by which Li exerts its action are not clearly understood, but it has been suggested that specific epigenetic mechanisms, such as methylation processes, may play a role. In this regard, DNA methylation patterns can be used to estimate epigenetic age (EpiAge), which is accelerated in BD patients and reversed by Li treatment. Our first aim was to compare the DNA methylation profile in peripheral blood between BD patients categorized as excellent responders to Li (Ex-Rp) and non-responders (N-Rp). Secondly, EpiAge was estimated to detect differential age acceleration between the two groups. A total of 130 differentially methylated positions (DMPs) and 16 differentially methylated regions (DMRs) between Ex-Rp (n = 26) and N-Rp (n = 37) were identified (FDR adjusted p-value < 0.05). We found 122 genes mapping the DMPs and DMRs, nine of which (HOXB6, HOXB3, HOXB-AS3, TENM2, CACNA1B, ANK3, EEF2K, CYP1A1, and SORCS2) had previously been linked to Li response. We found genes related to the GSK3β pathway to be highly represented. Using FUMA, we found enrichment in Gene Ontology Cell Component for the synapse. Gene network analysis highlighted functions related to the cell cycle, nervous system development and function, and gene expression. No significant differences in age acceleration were found between Ex-Rp and N-Rp for any of the epigenetic clocks analysed. Our findings indicate that a specific methylation pattern could determine the response to Li in BD patients. We also found that a significant portion of the differentially methylated genes are closely associated with the GSK3β pathway, reinforcing the role of this system in Li response. Future longitudinal studies with larger samples will help to elucidate the epigenetic mechanisms underlying Li response.

RANBP17 Overexpression Restores Nucleocytoplasmic Transport and Ameliorates Neurodevelopment in Induced DYT1 Dystonia Motor Neurons

DYT1 dystonia is a debilitating neurological movement disorder, and it represents the most frequent and severe form of hereditary primary dystonia. There is currently no cure for this disease due to its unclear pathogenesis. In our previous study utilizing patient-specific motor neurons (MNs), we identified distinct cellular deficits associated with the disease, including a deformed nucleus, disrupted neurodevelopment, and compromised nucleocytoplasmic transport (NCT) functions. However, the precise molecular mechanisms underlying these cellular impairments have remained elusive. In this study, we revealed the genome-wide changes in gene expression in DYT1 MNs through transcriptomic analysis. We found that those dysregulated genes are intricately involved in neurodevelopment and various biological processes. Interestingly, we identified that the expression level of RANBP17, a RAN-binding protein crucial for NCT regulation, exhibited a significant reduction in DYT1 MNs. By manipulating RANBP17 expression, we further demonstrated that RANBP17 plays an important role in facilitating the nuclear transport of both protein and transcript cargos in induced human neurons. Excitingly, the overexpression of RANBP17 emerged as a substantial mitigating factor, effectively restoring impaired NCT activity and rescuing neurodevelopmental deficits observed in DYT1 MNs. These findings shed light on the intricate molecular underpinnings of impaired NCT in DYT1 neurons and provide novel insights into the pathophysiology of DYT1 dystonia, potentially leading to the development of innovative treatment strategies.

Transcriptome wide identification, characterization and expression analysis of PHD gene family in Crocus sativus

Crocus sativus L., of the Iridaceae family, yields world's most prized spice, saffron. Saffron is well known for its distinctive aroma, odour and colour, which are imputed to the presence of some specific glycosylated apocarotenoids. Even though the main biosynthetic pathway and most of the enzymes leading to apocarotenoid production have been identified, the regulatory mechanisms that govern the developmental stage and tissue specific production of apocarotenoids in Crocus remain comparatively unravelled. Towards this, we report identification, and characterization of plant homeodomain (PHD) finger transcription factor family in Crocus sativus. We also report cloning and characterisation of CstPHD27 from C. sativus. CstPHD27 recorded highest expression in stigma throughout flower development. CstPHD27 exhibited expression pattern which corresponded to the apocarotenoid accumulation in Crocus stigmas. CstPHD27 is nuclear localized and transcriptionally active in yeast Y187 strain. Over-expression of CstPHD27 in Crocus stigmas enhanced apocarotenoid content by upregulating the biosynthetic pathway genes. This report on PHD finger transcription factor family from C. sativus may offer a basis for elucidating role of this gene family in this traditionally and industrially prized crop.

Supplementary Information

The online version contains supplementary material available at 10.1007/s12298-024-01410-3.

Neuroimaging genetics approaches to identify new biomarkers for the early diagnosis of autism spectrum disorder

Autism-spectrum disorders (ASDs) are developmental disabilities that manifest in early childhood and are characterized by qualitative abnormalities in social behaviors, communication skills, and restrictive or repetitive behaviors. To explore the neurobiological mechanisms in ASD, extensive research has been done to identify potential diagnostic biomarkers through a neuroimaging genetics approach. Neuroimaging genetics helps to identify ASD-risk genes that contribute to structural and functional variations in brain circuitry and validate biological changes by elucidating the mechanisms and pathways that confer genetic risk. Integrating artificial intelligence models with neuroimaging data lays the groundwork for accurate diagnosis and facilitates the identification of early diagnostic biomarkers for ASD. This review discusses the significance of neuroimaging genetics approaches to gaining a better understanding of the perturbed neurochemical system and molecular pathways in ASD and how these approaches can detect structural, functional, and metabolic changes and lead to the discovery of novel biomarkers for the early diagnosis of ASD.

Associations across 22 dental and craniovertebral anomalies or variations, sagittal skeletal relationships, and vertical growth patterns: a comprehensive epidemiological study of 43 dentoskeletal traits

INTRODUCTION

Despite researchers' recent interest in identifying links between some dental and craniovertebral abnormalities, there are many important, unassessed gaps in our knowledge of this matter. In addition, previous samples were small. This large study aimed to examine, for the first time, the occurrence/severity of numerous dental and skeletal anomalies or variations and their correlations with each other and with growth patterns.

METHODS

This epidemiological study was conducted on pretreatment radiographs of 1194 patients from 3 cities (815 females). Skeletal sagittal skeletal relationships and vertical growth patterns were determined. The occurrence/severity were assessed for: cervical vertebral fusion (CVF), atlas posterior arch deficiency (APAD), ponticulus posticus (PP), sella turcica bridging (STB), hypodontia, oligodontia, hyperdontia, missing of maxillary laterals, microdontia, macrodontia, root dilaceration, odontoma, taurodontism, dental fusion, dental gemination, enamel pearl, permanent molar ankylosis, primary molar ankylosis, dens in dente, dens invaginatus, dental impaction, ectopic eruption, and dental transposition. Incidental findings were recorded as well. Concurrent anomalies, sex dimorphism, and correlations across variables were examined statistically, adjusting for the false discovery rate (α = 0.05).

RESULTS

Prevalence was calculated for 43 dentoskeletal traits/anomalies (22 abnormalities/variations [plus their severities/types] as well as 21 incidentally found traits/anomalies). Dental impaction may be more common in hyperdivergent and severer cases of sella bridging; also, primary molar ankylosis was associated with missing teeth. Dental impaction was associated only with STB and not with PP, APAD, or vertebral fusion. The only association observed among the four skeletal anomalies was seen between APAD and CVF. Merely the variables 'sagittal skeletal relationships, vertical growth patterns, PP, and APAD' showed sexual dimorphism; of these, only vertical growth pattern and APAD remained sexually dimorphic after adjusting for the FDR; still, the other two remained marginally significant and worth further evaluations. Sex dimorphism did not exist in concurrent abnormalities. The skeletal Class III was associated with the concurrent occurrence of craniovertebral, dental, and dentoskeletal abnormalities. Skeletal Class I was associated with fewer occurrences of concurrent dental anomalies. Vertical growth patterns were not associated with concurrent dental or dentoskeletal anomalies. However, the hyperdivergent pattern was associated with fewer cases of concurrent craniovertebral abnormalities.

CONCLUSIONS

STB and hyperdivergent pattern were associated with dental impaction. However, APAD, CVF, or PP were not associated with dental impaction. APAD was associated with CVF. Sexual dimorphism existed conclusively in the case of vertical growth patterns and APAD. Concurrent abnormalities (dental, skeletal, and dentoskeletal) were associated with skeletal Class III.

MSX1 Gene Polymorphisms in Patients with non-Syndromic Cleft lip and Palate: A Tertiary Care Centre Based Case-Control Study from Central Kerala

OBJECTIVE

The purpose of this study was to investigate the contribution of MSX1 gene polymorphisms to the risk of developing NSCLP.

DESIGN

Case-Control Study.

SETTING

A tertiary care centre.

PATIENTS/PARTICIPANTS

The sample consisted of 200 subjects (100 cases and 100 controls).

INTERVENTIONS

None.

MAIN OUTCOME MEASURE(S)

Genotyping was performed by restriction fragment length polymorphism. Allele and genotype frequencies were calculated between patients and controls and analyzed using online Web Tools such as SISA and SNPstats. The MSX1 gene polymorphisms c. 799 GT, c.458 CA can be risk factors in the development of orofacial clefts.

RESULTS

In the cases, an association was found between NSCLP and c.799 and c.458 of the MSX1 gene when compared with the control. The dominant and overdominant models, c. 799 GT, c.458 CA genotypes and c. 799 T, c.458 A alleles in the population are said to be the main risk factors to develop the NSCLP in our study population. The genotype variation of c 799 G/T and c.458 C/A are revealed to be specifically contributing to an NSCLP-type Cleft lip and Palate. It is worth noting that NSCLP females in the study population showed a stronger association with heterozygous genotypes of c.799 and c.458. However, further investigation with a larger cohort is necessary to confirm these findings.

CONCLUSION

Overall the results of the study revealed that MSX1 c 799 G > T and c.458 C > A can be considered as one of the genetic risk factors in the formation of Non-Syndromic Cleft Lip and Palate in the study population.

Genomic signatures of selection, local adaptation and production type characterisation of East Adriatic sheep breeds

BACKGROUND

The importance of sheep breeding in the Mediterranean part of the eastern Adriatic has a long tradition since its arrival during the Neolithic migrations. Sheep production system is extensive and generally carried out in traditional systems without intensive systematic breeding programmes for high uniform trait production (carcass, wool and milk yield). Therefore, eight indigenous Croatian sheep breeds from eastern Adriatic treated here as metapopulation (EAS), are generally considered as multipurpose breeds (milk, meat and wool), not specialised for a particular type of production, but known for their robustness and resistance to certain environmental conditions. Our objective was to identify genomic regions and genes that exhibit patterns of positive selection signatures, decipher their biological and productive functionality, and provide a "genomic" characterization of EAS adaptation and determine its production type.

RESULTS

We identified positive selection signatures in EAS using several methods based on reduced local variation, linkage disequilibrium and site frequency spectrum (eROHi, iHS, nSL and CLR). Our analyses identified numerous genomic regions and genes (e.g., desmosomal cadherin and desmoglein gene families) associated with environmental adaptation and economically important traits. Most candidate genes were related to meat/production and health/immune response traits, while some of the candidate genes discovered were important for domestication and evolutionary processes (e.g., HOXa gene family and FSIP2). These results were also confirmed by GO and QTL enrichment analysis.

CONCLUSIONS

Our results contribute to a better understanding of the unique adaptive genetic architecture of EAS and define its productive type, ultimately providing a new opportunity for future breeding programmes. At the same time, the numerous genes identified will improve our understanding of ruminant (sheep) robustness and resistance in the harsh and specific Mediterranean environment.

Transcriptomes of human primary skin fibroblasts of healthy individuals reveal age-associated mRNAs and long noncoding RNAs

Changes in the transcriptomes of human tissues with advancing age are poorly cataloged. Here, we sought to identify the coding and long noncoding RNAs present in cultured primary skin fibroblasts collected from 82 healthy individuals across a wide age spectrum (22-89 years old) who participated in the GESTALT (Genetic and Epigenetic Signatures of Translational Aging Laboratory Testing) study of the National Institute on Aging, NIH. Using high-throughput RNA sequencing and a linear regression model, we identified 1437 coding RNAs (mRNAs) and 1177 linear and circular long noncoding (lncRNAs) that were differentially abundant as a function of age. Gene set enrichment analysis (GSEA) revealed select transcription factors implicated in coordinating the transcription of subsets of differentially abundant mRNAs, while long noncoding RNA enrichment analysis (LncSEA) identified RNA-binding proteins predicted to participate in the age-associated lncRNA profiles. In summary, we report age-associated changes in the global transcriptome, coding and noncoding, from healthy human skin fibroblasts and propose that these transcripts may serve as biomarkers and therapeutic targets in aging skin.

Unravelling the Role of Iroquois Homeobox 4 and its Interplay with Androgen Receptor in Prostate Cancer

Genome-wide association studies have linked Iroquois-Homeobox 4 (IRX4) as a robust expression quantitative-trait locus associated with prostate cancer (PCa) risk. However, the intricate mechanism and regulatory factors governing IRX4 expression in PCa remain poorly understood. Here, we unveil enrichment of androgen-responsive gene signatures in metastatic prostate tumors exhibiting heightened IRX4 expression. Furthermore, we uncover a novel interaction between IRX4 and the androgen receptor (AR) co-factor, FOXA1, suggesting that IRX4 modulates PCa cell behavior through AR cistrome alteration. Remarkably, we identified a distinctive short insertion-deletion polymorphism (INDEL), upstream of the IRX4 gene that differentially regulates IRX4 expression through the disruption of AR binding. This INDEL emerges as the most significant PCa risk-associated variant within the 5p15 locus, in a genetic analysis involving 82,591 PCa cases and 61,213 controls and was associated with PCa survival in patients undergoing androgen-deprivation therapy. These studies suggest the potential of this INDEL as a prognostic biomarker for androgen therapy in PCa and IRX4 as a potential therapeutic target in combination with current clinical management.

Association between sella turcica bridging and the impaction severity of palatally displaced canines: A retrospective study

INTRODUCTION

This retrospective study aimed to investigate the association between the extent of the bridging and dimensions of sella turcica and the impaction severity of palatally displaced canines. Secondarily, any possible association between skeletal age and gender was evaluated.

METHODS

Panoramic and cephalometric radiographs of 94 patients (63 female, 31 male; 19 pre-peak, 75 post-peak) with palatally displaced canines were evaluated. Sector classification and α angle were used to determine the impaction severity of palatally displaced canines on panoramic radiographs. The distance from the cusp tip of the palatally displaced canines to the occlusal plane (d) and the extent of the bridging and dimensions of the sella turcica were evaluated on cephalometric radiographs.

RESULTS

Sella turcica bridging and dimensions did not vary regarding the impaction severity of palatally displaced canines, but a significant association was found between sella turcica bridging and skeletal age (P = 0.038). Class II (33.3%) and Class III (12.0%) bridging was higher in postpubertal patients. No differences between females and males were detected for the extent of bridging and dimensions of the sella turcica.

CONCLUSIONS

These findings indicate no association between sella turcica bridging and dimensions and the impaction severity of palatally displaced canines. Sella turcica bridging is more frequent in the postpubertal period, whereas gender does not influence sella turcica bridging. More studies are needed to evaluate if the extent of sella turcica bridging may be indicative of severely impacted palatal canines, which in turn would allow for careful monitoring of patients from an early age and for the clinician to take preventive measures.

Interaction between retinol intake and ISX rs5755368 polymorphism in colorectal cancer risk: a case-control study in a Korean population

This study aimed to examine whether the ISX rs5755368 genotypes are associated with the effect of dietary retinol consumption on CRC risk. We recruited 923 CRC patients and 1846 controls to identify the association between dietary retinol and CRC risk. Dietary retinol intake was assessed using a semiquantitative food frequency questionnaire. Genotype data were available for 1419 patients (600 cases and 819 controls) of the total study population. Genotyping was performed using an Illumina MEGA Expanded Array. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were calculated using unconditional logistic regression models. Retinol intake was inversely associated with CRC (OR = 0.49; 95% CI = 0.37-0.63). Participants with AA genotype showed lower CRC risk than subjects carrying the G allele (AG + GG) (OR = 0.76; 95% CI = 0.58-0.99). A 68% reduced risk of CRC was related to subjects who had the highest retinol intake and carrying AA genotype compared to the risk of participants consumed the lowest retinol intake and carrying the G allele (OR = 0.32; 95% CI = 0.20-0.53; P interaction = 0.026). Retinol intake could be a protective factor for CRC risk while this association could be strengthened among individuals carrying the homozygous AA genotype.

Homeobox Genes in Odontogenic Lesions: A Scoping Review

BACKGROUND

Homeobox genes play crucial roles in tooth morphogenesis and development and thus mutations in homeobox genes cause developmental disorders such as odontogenic lesions. The aim of this scoping review is to identify and compile available data from the literatures on the topic of homeobox gene expression in odontogenic lesions.

METHOD

An electronic search to collate all the information on studies on homeobox gene expression in odontogenic lesions was carried out in four databases (PubMed, EBSCO host, Web of Science and Cochrane Library) with selected keywords. All papers which reported expression of homeobox genes in odontogenic lesions were considered.

RESULTS

A total of eleven (11) papers describing expression of homeobox genes in odontogenic lesions were identified. Methods of studies included next generation sequencing, microarray analysis, RT-PCR, Western blotting, in situ hybridization, and immunohistochemistry. The homeobox reported in odontogenic lesions includes LHX8 and DLX3 in odontoma; PITX2, MSX1, MSX2, DLX, DLX2, DLX3, DLX4, DLX5, DLX6, ISL1, OCT4 and HOX C in ameloblastoma; OCT4 in adenomatoid odontogenic tumour; PITX2 and MSX2 in primordial odontogenic tumour; PAX9 and BARX1 in odontogenic keratocyst; PITX2, ZEB1 and MEIS2 in ameloblastic carcinoma while there is absence of DLX2, DLX3 and MSX2 in clear cell odontogenic carcinoma.

CONCLUSIONS

This paper summarized and reviews the possible link between homeobox gene expression in odontogenic lesions. Based on the current available data, there are insufficient evidence to support any definite role of homeobox gene in odontogenic lesions.

Gsx2, but not Gsx1, is necessary for early forebrain patterning and long-term survival in zebrafish

BACKGROUND

Homeobox transcription factor encoding genes, genomic screen homeobox 1 and 2 (gsx1 and gsx2), are expressed during neurodevelopment in multiple vertebrates. However, we have limited knowledge of the dynamic expression of these genes through developmental time and the gene networks that they regulate in zebrafish.

RESULTS

We confirmed that gsx1 is expressed initially in the hindbrain and diencephalon and later in the optic tectum, pretectum, and cerebellar plate. gsx2 is expressed in the early telencephalon and later in the pallium and olfactory bulb. gsx1 and gsx2 are co-expressed in the hypothalamus, preoptic area, and hindbrain, however, rarely co-localize in the same cells. gsx1 and gsx2 mutant zebrafish were made with TALENs. gsx1 mutants exhibit stunted growth, however, they survive to adulthood and are fertile. gsx2 mutants experience swim bladder inflation failure that prevents survival. We also observed significantly reduced expression of multiple forebrain patterning distal-less homeobox genes in mutants, and expression of foxp2 was not significantly affected.

CONCLUSIONS

This work provides novel tools with which other target genes and functions of Gsx1 and Gsx2 can be characterized across the central nervous system to better understand the unique and overlapping roles of these highly conserved transcription factors.

Relationship between palatally impacted canines and dimensions and morphology of sella turcica: A cone-beam computed tomography study

INTRODUCTION

This study aimed to analyze the association of unilateral and bilateral palatal canine impaction with the dimensions and morphology of sella turcica from 3-dimensional cone-beam computed tomography (CBCT) images.

METHODS

CBCT images of patients with bilateral (BPI) (n = 12; 9 female 3 male; 20.75 ± 5.88 years) and unilateral (UPI) (n = 35; 22 female 13 male; 19.28 ± 5.57 years) palatally impacted canines were compared with a control group (n = 56; 34 female 22 male; 20.82 ± 4.88 years). Linear measurements regarding sella turcica were made, and its morphologic variations were categorized. Two group comparisons were made with the Student t test or Mann-Whitney U-test, whereas one-way analysis of variance or Kruskal-Wallis tests were used for multiple group comparisons. Categorical variables were compared using the chi-square or Fisher exact test as appropriate. The binary logistic regression analyses and correlations using Spearman or Pearson correlation analyses were used to determine associations between variables (P <0.05).

RESULTS

Sella diameter was significantly smaller in the BPI group compared to UPI and control groups. There was a significant association between sella diameter and BPI when compared with the control group (χ2[1] = 9.150; P = 0.008). There were no significant differences between groups in the distribution of sella turcica morphology.

CONCLUSIONS

Despite the similar genetic origin of the sella turcica region and teeth, the association of palatal canine impaction with dimensions and morphology of sella turcica was weak. Both local and genetic factors might contribute to the ectopic position of the canine.

Compendious survey of protein tandem repeats in inbred mouse strains

Short tandem repeats (STRs) play a crucial role in genetic diseases. However, classic disease models such as inbred mice lack such genome wide data in public domain. The examination of STR alleles present in the protein coding regions (are known as protein tandem repeats or PTR) can provide additional functional layer of phenotype regulars. Motivated with this, we analysed the whole genome sequencing data from 71 different mouse strains and identified STR alleles present within the coding regions of 562 genes. Taking advantage of recently formulated protein models, we also showed that the presence of these alleles within protein 3-dimensional space, could impact the protein folding. Overall, we identified novel alleles from a large number of mouse strains and demonstrated that these alleles are of interest considering protein structure integrity and functionality within the mouse genomes. We conclude that PTR alleles have potential to influence protein functions through impacting protein structural folding and integrity.

Decoding the byssus fabrication by spatiotemporal secretome analysis of scallop foot

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The first secretome about scallop byssal adhesion is profiled based on a new computational strategy.

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Scallop byssal secretome covered almost all of the known structural elements and functional domains of aquatic adhesives.

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The EGF-like domain containing proteins, the Tyr-rich proteins and 4C-repeats containing proteins are the main components of scallop byssus.

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A novel “nearby secretion” model of scallop byssus secretion and adhesion is proposed.

Secretome is involved in almost all physiological, developmental, and pathological processes, but to date there is still a lack of highly-efficient research strategy to comprehensively study the secretome of invertebrates. Adhesive secretion is a ubiquitous and essential physiological process in aquatic invertebrates with complicated protein components and unresolved adhesion mechanisms, making it a good subject for secretome profiling studies. Here we proposed a computational pipeline for systematic profiling of byssal secretome based on spatiotemporal transcriptomes of scallop. A total of 186 byssus-related proteins (BRPs) were identified, which represented the first characterized secretome of scallop byssal adhesion. Scallop byssal secretome covered almost all of the known structural elements and functional domains of aquatic adhesives, which suggested this secretome-profiling strategy had both high efficiency and accuracy. We revealed the main components of scallop byssus (including EGF-like domain containing proteins, the Tyr-rich proteins and 4C-repeats containing proteins) and the related modification enzymes primarily contributing to the rapid byssus assembly and adhesion. Spatiotemporal expression and co-expression network analyses of BRPs suggested a simultaneous secretion pattern of scallop byssal proteins across the entire region of foot and revealed their diverse functions on byssus secretion. In contrast to the previously proposed “root-initiated secretion and extension-based assembly” model, our findings supported a novel “foot-wide simultaneous secretion and in situ assembly” model of scallop byssus secretion and adhesion. Systematic analysis of scallop byssal secretome provides important clues for understanding the aquatic adhesive secretion process, as well as a common framework for studying the secretome of non-model invertebrates.

Regulated interaction of ID2 with the anaphase-promoting complex links progression through mitosis with reactivation of cell-type-specific transcription

Tissue-specific transcriptional activity is silenced in mitotic cells but it remains unclear whether the mitotic regulatory machinery interacts with tissue-specific transcriptional programs. We show that such cross-talk involves the controlled interaction between core subunits of the anaphase-promoting complex (APC) and the ID2 substrate. The N-terminus of ID2 is independently and structurally compatible with a pocket composed of core APC/C subunits that may optimally orient ID2 onto the APCCDH1 complex. Phosphorylation of serine-5 by CDK1 prevented the association of ID2 with core APC, impaired ubiquitylation and stabilized ID2 protein at the mitosis-G1 transition leading to inhibition of basic Helix-Loop-Helix (bHLH)-mediated transcription. The serine-5 phospho-mimetic mutant of ID2 that inefficiently bound core APC remained stable during mitosis, delayed exit from mitosis and reloading of bHLH transcription factors on chromatin. It also locked cells into a "mitotic stem cell" transcriptional state resembling the pluripotent program of embryonic stem cells. The substrates of APCCDH1 SKP2 and Cyclin B1 share with ID2 the phosphorylation-dependent, D-box-independent interaction with core APC. These results reveal a new layer of control of the mechanism by which substrates are recognized by APC.

Sella turcica bridging: a systematic review

PURPOSE

Sella turcica bridging (STB) has significant implications during neurosurgery, since it alters regional anatomy; however, no studies have investigated the global prevalence of STB. Our systematic review aimed to establish the global prevalence of STB, in specimens/individuals with and without comorbidities, in males and females, and of partial, complete, unilateral, and bilateral bridging.

METHODS

A literature search was conducted in MEDLINE/PubMed, ScienceDirect, and Google Scholar with various key words relating to Sella turcica bridging. Quantitative data were extracted and statistically analysed.

RESULTS

Eighty-two studies satisfied our inclusion criteria. The mean prevalence of STB was 26.54%, and most prevalent in Europe. STB was detected more frequently using radiological investigations. STB was less prevalent in healthy individuals (21.12%) when compared to individuals with comorbidities (33.31%). Partial STB was found to be the more prevalent in both individuals with (41.06%) and without (21.55%) comorbidities. The prevalence of unilateral and bilateral STB was only studied in healthy individuals, with unilateral bridging being the more prevalent (6.26% vs 3.84%).

CONCLUSION

The global overall prevalence of Sella turcica bridging in the general population was found to be higher than previously thought. Anatomical and embryological textbooks should consider including information on STB in their texts, due to its considerable prevalence and effects to the regional anatomy.

The concurrent stimulation of Wnt and FGF8 signaling induce differentiation of dental mesenchymal cells into odontoblast-like cells

Fibroblast growth factor 8 (FGF8) is known to be a potent stimulator of canonical Wnt/β-catenin activity, an essential factor for tooth development. In this study, we analyzed the effects of co-administration of FGF8 and a CHIR99021 (GSK3β inhibitor) on differentiation of dental mesenchymal cells into odontoblasts. Utilizing Cre-mediated EGFP reporter mice, dentin matrix protein 1 (Dmp1) expression was examined in mouse neonatal molar tooth germs. At birth, expression of Dmp1-EGFP was not found in mesenchymal cells but rather epithelial cells, after which Dmp1-positive cells gradually emerged in the mesenchymal area along with disappearance in the epithelial area. Primary cultured mesenchymal cells from neonatal tooth germ specimens showed loss of Dmp1-EGFP positive signals, whereas addition of Wnt3a or the CHIR99021 significantly regained Dmp1 positivity within approximately 2 weeks. Other odontoblast markers such as dentin sialophosphoprotein (Dspp) could not be clearly detected. Concurrent stimulation of primary cultured mesenchymal cells with the CHIR99021 and FGF8 resulted in significant upregulation of odonto/osteoblast proteins. Furthermore, increased expression levels of runt-related transcription factor 2 (Runx2), osterix, and osteocalcin were also observed. The present findings indicate that coordinated action of canonical Wnt/β-catenin and FGF8 signals is essential for odontoblast differentiation of tooth germs in mice.

Pili Torti: A Feature of Numerous Congenital and Acquired Conditions

Pili torti is a rare condition characterized by the presence of the hair shaft, which is flattened at irregular intervals and twisted 180° along its long axis. It is a form of hair shaft disorder with increased fragility. The condition is classified into inherited and acquired. Inherited forms may be either isolated or associated with numerous genetic diseases or syndromes (e.g., Menkes disease, Björnstad syndrome, Netherton syndrome, and Bazex-Dupré-Christol syndrome). Moreover, pili torti may be a feature of various ectodermal dysplasias (such as Rapp-Hodgkin syndrome and Ankyloblepharon-ectodermal defects-cleft lip/palate syndrome). Acquired pili torti was described in numerous forms of alopecia (e.g., lichen planopilaris, discoid lupus erythematosus, dissecting cellulitis, folliculitis decalvans, alopecia areata) as well as neoplastic and systemic diseases (such as cutaneous T-cell lymphoma, scalp metastasis of breast cancer, anorexia nervosa, malnutrition, cataracts, and chronic graft-vs.-host disease). The condition may also be induced by several drugs (epidermal growth factor receptor inhibitors, oral retinoids, sodium valproate, and carbamide perhydrate). The diagnosis of pili torti is based on trichoscopic or microscopic examination. As pili torti is a marker of numerous congenital and acquired disorders, in every case, the search for the signs of underlying conditions is recommended.

Ancient autozygous segments subject to positive selection suggest adaptive immune responses in West African cattle

Small-sized and trypanotolerant West African taurine (Bos taurus) cattle are a unique case of human-mediated process of adaptation to a challenging environment. Extensive gene flow with Sahelian zebu (B. indicus), bigger and with some resistance to tick attack, occurred for centuries and allowed the apparition of stable crossbred populations (sanga) having intermediate characteristics. Up to 237 individuals belonging to 10 different taurine, zebu and sanga cattle populations sampled in Benin, Burkina Faso and Niger were typed using the BovineHD BeadChip of Illumina to identify signatures of selection, assessed using three different Extended-Haplotype-Homozygosity-based statistics, overlapping with ancient, originated 1024 or 2048 generations ago, Homozygosity-By-Descent segments in the cattle genome. Candidate genomic regions were defined ensuring their importance within cattle type and using zebu as reference. Functional annotation analysis identified four statistically significant Annotation Clusters in taurine cattle (from ACt1 to ACt4), one (ACs1) in sanga, and another (ACz1) in zebu cattle, fitting well with expectations. ACt1 included genes primarily associated with innate immunity; ACt2 involved bitter taste receptor genes of importance to adaptation to changing environments; ACt3 included 68 genes coding ATP-binding proteins, some of them located on trypanotolerance-related QTL regions, that can partially underlie immune response and the additive mechanism of trypanotolerance; ACt4 was associated with growth and small size (NPPC gene); ACs1 included genes involved in immune response; and ACz1 is related with ectoparasite resistance. Our results provide a new set of genomic areas and candidate genes giving new insights on the genomic impact of adaptation in West African cattle.

A New Catalog of Structural Variants in 1,301 A. thaliana Lines from Africa, Eurasia, and North America Reveals a Signature of Balancing Selection at Defense Response Genes

Genomic variation in the model plant Arabidopsis thaliana has been extensively used to understand evolutionary processes in natural populations, mainly focusing on single-nucleotide polymorphisms. Conversely, structural variation has been largely ignored in spite of its potential to dramatically affect phenotype. Here, we identify 155,440 indels and structural variants ranging in size from 1 bp to 10 kb, including presence/absence variants (PAVs), inversions, and tandem duplications in 1,301 A. thaliana natural accessions from Morocco, Madeira, Europe, Asia, and North America. We show evidence for strong purifying selection on PAVs in genes, in particular for housekeeping genes and homeobox genes, and we find that PAVs are concentrated in defense-related genes (R-genes, secondary metabolites) and F-box genes. This implies the presence of a "core" genome underlying basic cellular processes and a "flexible" genome that includes genes that may be important in spatially or temporally varying selection. Further, we find an excess of intermediate frequency PAVs in defense response genes in nearly all populations studied, consistent with a history of balancing selection on this class of genes. Finally, we find that PAVs in genes involved in the cold requirement for flowering (vernalization) and drought response are strongly associated with temperature at the sites of origin.

Dental defects in the primary dentition associated with hypophosphatasia from biallelic ALPL mutations

ALPL encodes tissue-nonspecific alkaline phosphatase (TNAP), an enzyme expressed in bone, teeth, liver, and kidney. ALPL loss-of-function mutations cause hypophosphatasia (HPP), an inborn error-of-metabolism that produces skeletal and dental mineralization defects. Case reports describe widely varying dental phenotypes, making it unclear how HPP comparatively affects the three unique dental mineralized tissues: enamel, dentin, and cementum. We hypothesized that HPP affected all dental mineralized tissues and aimed to establish quantitative measurements of dental tissues in a subject with HPP. The female proband was diagnosed with HPP during childhood based on reduced alkaline phosphatase activity (ALP), mild rachitic skeletal effects, and premature primary tooth loss. The diagnosis was subsequently confirmed genetically by the presence of compound heterozygous ALPL mutations (exon 5: c.346G>A, p.A116T; exon 10: c.1077C>G, p.I359M). Dental defects in 8 prematurely exfoliated primary teeth were analyzed by high resolution micro-computed tomography (micro-CT) and histology. Similarities to the Alpl^-/- mouse model of HPP were identified by additional analyses of murine dentoalveolar tissues. Primary teeth from the proband exhibited substantial remaining root structure compared to healthy control teeth. Enamel and dentin densities were not adversely affected in HPP vs. control teeth. However, analysis of discrete dentin regions revealed an approximate 10% reduction in the density of outer mantle dentin of HPP vs. control teeth. All 4 incisors and the molar lacked acellular cementum by micro-CT and histology, but surprisingly, 2 of 3 prematurely exfoliated canines exhibited apparently normal acellular cementum. Based on dentin findings in the proband's teeth, we examined dentoalveolar tissues in a mouse model of HPP, revealing that the delayed initiation of mineralization in the incisor mantle dentin was associated with a broader lack of circumpulpal dentin mineralization. This study describes a quantitative approach to measure effects of HPP on dental tissues. This approach has uncovered a previously unrecognized novel mantle dentin defect in HPP, as well as a surprising and variable cementum phenotype within the teeth from the same HPP subject.

Identification of oral symptoms associated with atopic dermatitis in adolescents: Results from the Korea national representative survey 2009-2017

The relationship between oral health and atopic dermatitis (AD) remains unclear. Here we investigated the association between oral health status and AD using data from 634,299 subjects in the Korean Youth Risk Behavior Survey (KYRBS). Participants with oral symptoms were defined as those with any of following: sensitive teeth, toothache, bleeding gums or gum pain, and dry mouth. Current AD was determined by the question if participant had been diagnosed with AD from doctor within the past 12 months. We estimated the odds ratio (OR) for AD diagnosis according to the presence of oral symptoms. The OR for current AD, which is a dependent variable, was significantly increased in participants with oral symptoms, which are independent variables, in an adjusted model (OR, 1.27; 95% confidence interval [CI], 1.26–1.29; P < 0.001). In detailed analyses, all four oral symptoms were significantly associated with AD diagnosis: sensitive teeth (OR, 1.21; CI, 1.19–1.23; P < 0.001), bad breath (OR, 1.18; CI, 1.17–1.20; P < 0.001), toothache (OR, 1.18; CI, 1.16–1.20; P < 0.001), and bleeding gums (OR, 1.14; CI, 1.12–1.16; P < 0.001). In the presence of oral symptoms, the ORs for having two or more allergic diseases (AD, allergic rhinitis, and/or asthma) were higher than that of AD alone. In this study, oral symptoms appeared to be associated with AD in Korean adolescences.

HOX gene cluster (de)regulation in brain: from neurodevelopment to malignant glial tumours

HOX genes encode a family of evolutionarily conserved homeodomain transcription factors that are crucial both during development and adult life. In humans, 39 HOX genes are arranged in four clusters (HOXA, B, C, and D) in chromosomes 7, 17, 12, and 2, respectively. During embryonic development, particular epigenetic states accompany their expression along the anterior-posterior body axis. This tightly regulated temporal-spatial expression pattern reflects their relative chromosomal localization, and is critical for normal embryonic brain development when HOX genes are mainly expressed in the hindbrain and mostly absent in the forebrain region. Epigenetic marks, mostly polycomb-associated, are dynamically regulated at HOX loci and regulatory regions to ensure the finely tuned HOX activation and repression, highlighting a crucial epigenetic plasticity necessary for homeostatic development. HOX genes are essentially absent in healthy adult brain, whereas they are detected in malignant brain tumours, namely gliomas, where HOX genes display critical roles by regulating several hallmarks of cancer. Here, we review the major mechanisms involved in HOX genes (de)regulation in the brain, from embryonic to adult stages, in physiological and oncologic conditions. We focus particularly on the emerging causes of HOX gene deregulation in glioma, as well as on their functional and clinical implications.

Associations among palatal impaction of canine, sella turcica bridging, and ponticulus posticus (atlas arcuate foramen)

INTRODUCTION

The palatal impaction of canine (PIC) can be predicted by some head and neck skeletal anomalies or variants. Since studies on this regard (especially vertebral anomalies) are scarce, this study was conducted.

METHODS

This case-control study was done on 46 PIC orthodontic patients (34 females, 12 males) and 46 control orthodontic patients (36 females, 10 males). The diagnosis of PIC was done on lateral cephalographs and panoramic radiographs. On cephalographs, sella turcica bridging (occurrence and severity) and ponticulus posticus (occurrence and severity) were assessed. Associations between PIC, sella bridging, and ponticulus posticus were examined statistically (α = 0.05, β ≤ 0.2).

RESULTS

Cases' and controls' mean ages were 17.7 ± 4.0 and 17.4 ± 3.5, respectively. Of the case subjects, 22, 22, and 2 had respectively types I (normal), II, and III of sella bridging, while these numbers were 34, 12, and 0 in controls (chi-square P = 0.023 for severity, 0.010 for occurrence). Ponticulus posticus was observed in 28 cases (7 completed) and 17 controls (6 completed, P = 0.022 for occurrence, 0.056 for severity). Sella bridging was not associated with ponticulus posticus (Spearman P = 0.150). According to binary logistic regression, sella bridging can increase the odds of palatal canine impaction for OR = 2.8 times, while ponticulus posticus for OR = 2.6. Age and sex did not affect sella bridging or ponticulus posticus.

CONCLUSIONS

Both sella bridging and ponticulus posticus can predict an increased rate of PIC for more than 2.5 times.

Profiling of immune related genes silenced in EBV-positive gastric carcinoma identified novel restriction factors of human gammaherpesviruses

EBV-associated gastric cancer (EBVaGC) is characterized by high frequency of DNA methylation. In this study, we investigated how epigenetic alteration of host genome contributes to pathogenesis of EBVaGC through the analysis of transcriptomic and epigenomic datasets from NIH TCGA (The Cancer Genome Atlas) consortium. We identified that immune related genes (IRGs) is a group of host genes preferentially silenced in EBV-positive gastric cancers through DNA hypermethylation. Further functional characterizations of selected IRGs reveal their novel antiviral activity against not only EBV but also KSHV. In particular, we showed that metallothionein-1 (MT1) and homeobox A (HOXA) gene clusters are down-regulated via EBV-driven DNA hypermethylation. Several MT1 isoforms suppress EBV lytic replication and release of progeny virions as well as KSHV lytic reactivation, suggesting functional redundancy of these genes. In addition, single HOXA10 isoform exerts antiviral activity against both EBV and KSHV. We also confirmed the antiviral effect of other dysregulated IRGs, such as IRAK2 and MAL, in scenario of EBV and KSHV lytic reactivation. Collectively, our results demonstrated that epigenetic silencing of IRGs is a viral strategy to escape immune surveillance and promote viral propagation, which is overall beneficial to viral oncogenesis of human gamma-herpesviruses (EBV and KSHV), considering that these IRGs possess antiviral activities against these oncoviruses.

Evaluation of the relationship between impacted canines and three-dimensional sella morphology

PURPOSE

The purpose of this study was to assess the three-dimensional morphometric features of the sella turcica using cone beam computed tomography (CBCT) in subjects with unilateral and bilateral maxillary impacted canines and normal controls.

METHODS

In this retrospective study, CBCT images captured with ultra-low dose protocol of 73 subjects (21 males, 52 females; mean age 20.01 ± 6.53 years) with unilateral or bilateral maxillary impacted canines (29 unilateral and 29 bilateral) and 15 controls were evaluated. Nineteen different measurements of the pituitary fossa were made on CBCT images. To evaluate the normality, the Kolmogorov-Smirnov test was used. The nonparametric statistical Kruskal-Wallis and Mann-Whitney U tests were applied to analyze the significant differences among and between the groups. Statistical significance was set at 5%.

RESULTS

No measurement differed significantly among the groups (all p > 0.05) other than the right sella length, which differed between the unilateral and bilateral test groups and the unilateral test group and controls (both p < 0.05). The bilateral test group and control group did not differ significantly, but both exhibited greater right sella length than did the unilateral test group (p > 0.05).

CONCLUSIONS

Other than the right sella length, there were no among-group differences in the mean pituitary fossa measurements of subjects with impacted unilateral and bilateral canines and normally erupted canines. The right sella length was lower in subjects with impacted unilateral canines than in those with bilateral impacted canines and normal controls.

DLX3 epigenetically regulates odontoblastic differentiation of hDPCs through H19/miR-675 axis

OBJECTIVES

A novel mutation (c.533 A > G; Q178R) in DLX3 gene is responsible for Tricho-Dento-Osseous (TDO) syndrome. As one of features of TDO syndrome is dentin hypoplasia, we explored the mechanism regarding dentin defects in TDO syndrome.

DESIGN

hDPCs were obtained from the healthy premolars, stably expressing hDPCs were generated using recombinant lentiviruses. Quantitative methylation analysis, DNMT3B activity, CHIP, and evaluation of odonto-differentiation ability of hDPCs assays were performed.

RESULTS

Novel mutant DLX3 (MU-DLX3) significantly inhibited the expression of long non-coding RNA H19 and resulted in hyper-methylation of H19 in MU group, rescue studies showed that up-regulation the expression of H19 and demethylation of H19 in MU group were able to rescue the effect of MU-DLX3. Subsequently, miR-675, encoded by H19, was also able to rescue the above effects of MU-DLX3. Thus, we proposed that MU-DLX3 regulated odontoblastic differentiation of hDPCs through H19/miR-675 axis. Through CHIP and DNMT3B activity assays disclosed the underlying mechanism by which MU-DLX3 altered H19 expression and methylation status in MU group by increasing H3K9me3 enrichment and DNMT3B activity.

CONCLUSIONS

Our new findings, for the first time, suggest that MU-DLX3 significantly inhibits hDPCs differentiation via H19/miR-675 axis and provides a new mechanism insight into how MU-DLX3 epigenetically alters H19 methylation status and expression contributes to dentin hypoplasia in TDO syndrome.

Dlx5 and Dlx6 can antagonize cell division at the G1/S checkpoint

Background

Dlx5 and Dlx6 stimulate differentiation of diverse progenitors during embryonic development. Their actions as pro-differentiation transcription factors includes the up-regulation of differentiation markers but the extent to which differentiation may also be stimulated by regulation of the cell cycle has not been addressed.

Results

We document that expression of Dlx5 and Dlx6 antagonizes cell proliferation in a variety of cell types without inducing apoptosis or promoting cell cycle exit. Rather, a variety of evidence indicates that elevated Dlx5 and Dlx6 expression reduces the proportion of cells in S phase and affects the length of the cell cycle.

Conclusions

Antagonism of S-phase entry by Dlx5 and Dlx6 proteins likely represents a lineage-independent function to effect Dlx-mediated differentiation in multiple progenitor cell types.

Down-regulation of DKK1 and Wnt1/β-catenin pathway by increased homeobox B7 resulted in cell differentiation suppression of intrauterine fetal growth retardation in human placenta

OBJECTIVE

This study aimed to test the influence of homeobox B7 (HoxB7) on the proliferation, invasion, and migration of human trophoblast cells and to reveal the down-regulation of HoxB7 on the transcriptional suppression of Dick Kopf-related protein1 (DKK1) and of Cysteine-rich glycosylated wingless protein 1 (Wnt1)/β-catenin in intrauterine fetal growth retardation (FGR).

METHODS

Quantitative measurement of HoxB7, DKK1, Wnt1, and β-catenin was performed in human placentas collected from normal pregnancies and from FGR with quantitative real time PCR (qRT-PCR). Cultured HTR-8/SVneo cells, transfected with a lentiviral plasmid that in-frame expresses human HoxB7 gene, were applied to functional assessment to study the biological impact of HoxB7 gene on DKK1, Wnt1, and β-catenin. Counting Kit-8, Transwell invasion assays, and flow cytometry were applied for the functional measurements.

RESULTS

The expression of HoxB7 was significantly increased, and of DKK1, Wnt1, and β-catenin was decreased, in FGR placenta tissues and in HTR-8/SVneo cells. Function studies revealed that overexpression of HoxB7 inhibited proliferation, migration, and invasion in HTR-8/SVneo cells. DKK1, Wnt1, and β-catenin were down-regulated in HTR-8/SVneo cells, inversely correlated with HoxB7 expression. Overexpression of HoxB7 showed a suppressive effect on proliferation, migration, and invasion in the HTR-8/SVneo cells.

CONCLUSIONS

Our results indicate that HoxB7 inhibited human trophoblast cell differentiation by down-regulating DKK1 expression and that it may affect transcription of Wnt1/β-catenin. The activation of HoxB7 might suppress the cell differentiation in HTR-8/SVneo cell cultures. The Wnt/β-catenin signaling pathway may play a significant role in the pathogenesis of FGR by regulating the invasion and proliferation of trophoblasts.

Differential expression of p120-catenin 1 and 3 isoforms in epithelial tissues

P120 catenin (p120) is a non-redundant master regulatory protein of cadherin-based cell-cell junctions, intracellular signaling, and tissue homeostasis and repair. Alternative splicing can generate p120 isoforms 1 and 3 (p120-1 and p120-3), which are implicated in non-overlapping functions by differential expression regulation and unique interactions in different cell types, with often predominant expression of p120-1 in mesenchymal cells, and p120-3 generally prevalent in epithelial cells. However, the lack of specific p120-3 protein detection has precluded analysis of their relative abundance in tissues. Here, we have developed a p120-3 isoform-specific antibody and analyzed the p120-3 localization relative to p120-1 in human tissues. p120-3 but not p120-1 is highly expressed in cell-cell junctions of simple gastrointestinal epithelia such as colon and stomach, and the acini of salivary glands and the pancreas. Conversely, the basal layer of the epidermis and hair follicles expressed p120-1 with reduced p120-3, whereas most other epithelia co-expressed p120-3 and p120-1, including bronchial epithelia and mammary luminal epithelial cells. These data provide an inventory of tissue-specific p120 isoform expression and suggest a link between p120 isoform expression and epithelial differentiation.

miR-675 promotes odontogenic differentiation of human dental pulp cells by epigenetic regulation of DLX3

In a previous study, we showed that microRNA-675 (miR-675) was significantly down-regulated in patients with tricho-dento-osseous (TDO) syndrome. One of the main features of TDO syndrome is dentin hypoplasia. Thus, we hypothesize that miR-675 plays a role in dentin development. In this study, we determined the role of miR-675 in the odontogenic differentiation of human dental pulp cells (hDPCs). Stable overexpression and knockdown of miR-675 in hDPCs were performed using recombinant lentiviruses containing U6 promoter-driven miR-675 and short hairpin-miR675 expression cassettes, respectively. Alkaline phosphatase (ALP) assay, Alizarin red staining assay, quantitative polymerase chain reaction (qPCR), Western blot analysis, and immunofluorescent staining revealed the promotive effects of miR-675 on the odontogenic differentiation of hDPCs. Further, we found that miR-675 facilitates the odontogenic differentiation process of hDPCs by epigenetic regulation of distal-less homeobox (DLX3). Thus, for the first time, we determined that miR-675 regulates the odontogenic differentiation of hDPCs by inhibiting the DNA methyltransferase 3 beta (DNMT3B)-mediated methylation of DLX3. Our findings uncover an unanticipated regulatory role for miR-675 in the odontogenic differentiation of hDPCs by epigenetic changes in DLX3 and provide novel insight into dentin hypoplasia feature in TDO patients.

Homeobox C10 inhibits the osteogenic differentiation potential of mesenchymal stem cells

PURPOSE

Mesenchymal stem cells (MSCs) are a reliable cell source for tissue regeneration. However, the molecular mechanisms underlying the directed differentiation of MSCs remain unclear which impedes potential clinical applications. Recent studies have discovered that Homeobox (HOX) genes are involved in the differentiation regulation of MSCs and bone formation. In this study, we investigate the HOXC10 function in the osteogenic differentiation potential of MSCs.

MATERIALS AND METHODS

Stem cells from apical papilla (SCAPs) and adipose-derived stem cells (ADSCs) were used in this study. Alkaline phosphatase (ALP) activity assays, ALP staining, Alizarin red staining, quantitative calcium analysis, osteogenesis-associated gene expression, and in vivo transplantation experiments were used to study osteogenic differentiation potential.

RESULTS

Our results showed that overexpression of HOXC10 in SCAPs inhibited ALP activity and mineralization in vitro and decreased the mRNA expression of collagen alpha-1 (I) chain, bone sialoprotein, osteocalcin, and a key transcription factor, runt-related transcription factor 2, in SCAPs. Depletion of HOXC10 promoted osteogenic differentiation in SCAPs in vitro. In addition, in vivo transplantation experiments in nude mice confirmed that SCAPs osteogenesis was triggered when HOXC10 was downregulated. Furthermore, depletion of HOXC10 also enhanced osteogenic differentiation in ADSCs.

CONCLUSIONS

Taken together, these results indicated that HOXC10 decreased the MSC osteogenic differentiation potential. Thus, inhibition of HOXC10 in MSCs might have the potential to improve tissue regeneration and provide insight into the mechanism underlying the directed differentiation of MSCs.

Homeobox genes and tooth development: Understanding the biological pathways and applications in regenerative dental science

OBJECTIVES

Homeobox genes are a group of conserved class of transcription factors that function as key regulators during the embryonic developmental processes. They act as master regulator for developmental genes, which involves coordinated actions of various auto and cross-regulatory mechanisms. In this review, we summarize the expression pattern of homeobox genes in relation to the tooth development and various signaling pathways or molecules contributing to the specific actions of these genes in the regulation of odontogenesis.

MATERIALS AND METHODS

An electronic search was undertaken using combination of keywords e.g. Homeobox genes, tooth development, dental diseases, stem cells, induced pluripotent stem cells, gene control region was used as search terms in PubMed and Web of Science and relevant full text articles and abstract were retrieved that were written in English. A manual hand search in text books were also carried out. Articles related to homeobox genes in dentistry and tissue engineering and regenerative medicine of odontogenesis were selected.

RESULTS

The possible perspective of stem cells technology in odontogenesis and subsequent analysis of gene correction pertaining to dental disorders through the possibility of induced pluripotent stem cells technology is also inferred.

CONCLUSIONS

We demonstrate the promising role of tissue engineering and regenerative medicine on odontogenesis, which can generate a new ray of hope in the field of dental science.

Leaf primordium size specifies leaf width and vein number among row-type classes in barley

Exploring genes with impact on yield-related phenotypes is the preceding step to accomplishing crop improvements while facing a growing world population. A genome-wide association scan on leaf blade area (LA) in a worldwide spring barley collection (Hordeum vulgare L.), including 125 two- and 93 six-rowed accessions, identified a gene encoding the homeobox transcription factor, Six-rowed spike 1 (VRS1). VRS1 was previously described as a key domestication gene affecting spike development. Its mutation converts two-rowed (wild-type VRS1, only central fertile spikelets) into six-rowed spikes (mutant vrs1, fully developed fertile central and lateral spikelets). Phenotypic analyses of mutant and wild-type leaves revealed that mutants had an increased leaf width with more longitudinal veins. The observed significant increase of LA and leaf nitrogen (%) during pre-anthesis development in vrs1 mutants also implies a link between wider leaf and grain number, which was validated from the association of vrs1 locus with wider leaf and grain number. Histological and gene expression analyses indicated that VRS1 might influence the size of leaf primordia by affecting cell proliferation of leaf primordial cells. This finding was supported by the transcriptome analysis of mutant and wild-type leaf primordia where in the mutant transcriptional activation of genes related to cell proliferation was detectable. Here we show that VRS1 has an independent role on barley leaf development which might influence the grain number.

A novel pathogenic variant in the FZD6 gene causes recessive nail dysplasia in a large Iranian kindred

BACKGROUND

Nail disorder nonsyndromic congenital (NDNC) is a very rare clinically and genetically heterogeneous disease inherited both in recessive or dominant modes. FZD6 is a component of Wnt-FZD signaling pathway in which recessive loss-of-function variants in the corresponding genes could lead to nail anomalies.

OBJECTIVE

A large multiplex family with NDNC was referred for genetic counselling. Thorough genetic evaluation was performed.

METHODS

PCR-Sanger sequencing was carried out for the coding exons and exon-intron boundaries of the FZD6 gene. Co-segregation analysis, in silico evaluation and computational protein modeling was accomplished.

RESULTS

A homozygous 1bp deletion variant, c.1859delC (p.Ser620Cysfs*75), leading to a truncating protein was found in the patient. Parents were heterozygous for the variant. The variant was found to be co-segreagting with the phenotype in the family. Computational analysis and protein modeling revealed its pathogenic consequence by disturbing the cytoplasmic domain structure and signaling through loss of phosphorylation residues. The variant met the criteria of being pathogenic according to the ACMG guideline.

CONCLUSIONS

This is the first report of the genetic diagnosis of NDNC in Iran. We also report a novel pathogenic variant. The study of the FZD6 gene is recommended as the first step in the diagnostic routing of the autosomal recessive NDNC patients with enlarged nails.

A novel DLX3-PKC integrated signaling network drives keratinocyte differentiation

Epidermal homeostasis relies on a well-defined transcriptional control of keratinocyte proliferation and differentiation, which is critical to prevent skin diseases such as atopic dermatitis, psoriasis or cancer. We have recently shown that the homeobox transcription factor DLX3 and the tumor suppressor p53 co-regulate cell cycle-related signaling and that this mechanism is functionally involved in cutaneous squamous cell carcinoma development. Here we show that DLX3 expression and its downstream signaling depend on protein kinase C α (PKCα) activity in skin. We found that following 12-O-tetradecanoyl-phorbol-13-acetate (TPA) topical treatment, DLX3 expression is significantly upregulated in the epidermis and keratinocytes from mice overexpressing PKCα by transgenic targeting (K5-PKCα), resulting in cell cycle block and terminal differentiation. Epidermis lacking DLX3 (DLX3cKO), which is linked to the development of a DLX3-dependent epidermal hyperplasia with hyperkeratosis and dermal leukocyte recruitment, displays enhanced PKCα activation, suggesting a feedback regulation of DLX3 and PKCα. Of particular significance, transcriptional activation of epidermal barrier, antimicrobial peptide and cytokine genes is significantly increased in DLX3cKO skin and further increased by TPA-dependent PKC activation. Furthermore, when inhibiting PKC activity, we show that epidermal thickness, keratinocyte proliferation and inflammatory cell infiltration are reduced and the PKC-DLX3-dependent gene expression signature is normalized. Independently of PKC, DLX3 expression specifically modulates regulatory networks such as Wnt signaling, phosphatase activity and cell adhesion. Chromatin immunoprecipitation sequencing analysis of primary suprabasal keratinocytes showed binding of DLX3 to the proximal promoter regions of genes associated with cell cycle regulation, and of structural proteins and transcription factors involved in epidermal differentiation. These results indicate that Dlx3 potentially regulates a set of crucial genes necessary during the epidermal differentiation process. Altogether, we demonstrate the existence of a robust DLX3–PKCα signaling pathway in keratinocytes that is crucial to epidermal differentiation control and cutaneous homeostasis.

Associations between occlusion, jaw relationships, craniofacial dimensions and the occurrence of palatally-displaced canines

BACKGROUND AND PURPOSE

Cephalometric and arch measurements might predict the occurrence of a palatally-displaced impacted maxillary canine (PDC). Despite their clinical importance, studies in this regard are limited and controversial.

METHODS

In this case-control study, 35 PDC patients and 77 controls aged over 13 years were examined. Eleven cephalometric measurements: N-S, ANS-PNS, ANS-N, S-N-ANS, facial angle (FH/NPog), SNA, SNB, Y-axis (SN/SGn), gonial angle, Go-Gn/SN, and Jarabak Index were performed. The maxillary and mandibular intermolar and interpremolar widths were measured. Patients' sagittal skeletal relationships and centric occlusions (molar) were measured by radiographic and cast examinations. The differences between the two groups in terms of the above-mentioned cephalometric and anatomic variables were assessed using Chi² and Mann-Whitney U-tests (α=0.05).

RESULTS

Chi² showed a significant negative association between dentoalveolar class I (molar) and PDC occurrence (P=0.018), but not between PDC and skeletal sagittal relationships. Facial angle (FH/NPog) and Y-axis (SN/SGn) were more obtuse in patients with PDC (P<0.05). No arch dimensions differed between the two groups.

CONCLUSIONS

PDC tends to accompany molar class II/III but is not associated with upper or lower jaw widths or lengths. Vertical dimensions might be smaller in PDC patients. Some variables were inconclusive and need future assessments.

Control of Hoxd gene transcription in the mammary bud by hijacking a preexisting regulatory landscape

Vertebrate Hox genes encode transcription factors operating during the development of multiple organs and structures. However, the evolutionary mechanism underlying this remarkable pleiotropy remains to be fully understood. Here, we show that Hoxd8 and Hoxd9, two genes of the HoxD complex, are transcribed during mammary bud (MB) development. However, unlike in other developmental contexts, their coexpression does not rely on the same regulatory mechanism. Hoxd8 is regulated by the combined activity of closely located sequences and the most distant telomeric gene desert. On the other hand, Hoxd9 is controlled by an enhancer-rich region that is also located within the telomeric gene desert but has no impact on Hoxd8 transcription, thus constituting an exception to the global regulatory logic systematically observed at this locus. The latter DNA region is also involved in Hoxd gene regulation in other contexts and strongly interacts with Hoxd9 in all tissues analyzed thus far, indicating that its regulatory activity was already operational before the appearance of mammary glands. Within this DNA region and neighboring a strong limb enhancer, we identified a short sequence conserved in therian mammals and capable of enhancer activity in the MBs. We propose that Hoxd gene regulation in embryonic MBs evolved by hijacking a preexisting regulatory landscape that was already at work before the emergence of mammals in structures such as the limbs or the intestinal tract.

Isolated recessive nail dysplasia caused by FZD6 mutations: report of three families and review of the literature

Congenital abnormalities of the nail are rare conditions that are most frequently associated with congenital ectodermal syndromes involving several of the epidermal appendages including the skin, teeth, hair and nails. Isolated recessive nail dysplasia (IRND) is much rarer but has recently been recognized as a condition resulting in 20‐nail dystrophy in the absence of other cutaneous or extracutaneous findings. A few case reports have identified mutations in the Frizzled 6 (FZD6) gene in families presenting with abnormal nails consistent with IRND. These reports have highlighted the role of Wnt–FZD signalling in the process of nail formation. We report three families presenting with features of IRND, in whom we identified mutations in FZD6, including one previously unreported mutation.

Test Tube Tooth: The Next Big Thing

Unlike some vertebrates and fishes, humans do not have the capacity for tooth regeneration after the loss of permanent teeth. Although artificial replacement with removable dentures, fixed prosthesis and implants is possible through advances in the field of prosthetic dentistry, it would be ideal to recreate a third set of natural teeth to replace lost dentition. For many years now, researchers in the field of tissue engineering have been trying to bioengineer dental tissues as well as whole teeth. In order to attain a whole tooth through dental engineering, that has the same or nearly same biological, mechanical and physical properties of a natural tooth, it's necessary to deal with all the cells and tissues which are concerned with the formation, maintenance and repair of the tooth. In this article we review the steps involved in odontogenesis or organogenesis of a tooth and progress in the bioengineering of a whole tooth.

A Complex Structural Variation on Chromosome 27 Leads to the Ectopic Expression of HOXB8 and the Muffs and Beard Phenotype in Chickens

Muffs and beard (Mb) is a phenotype in chickens where groups of elongated feathers gather from both sides of the face (muffs) and below the beak (beard). It is an autosomal, incomplete dominant phenotype encoded by the Muffs and beard (Mb) locus. Here we use genome-wide association (GWA) analysis, linkage analysis, Identity-by-Descent (IBD) mapping, array-CGH, genome re-sequencing and expression analysis to show that the Mb allele causing the Mb phenotype is a derived allele where a complex structural variation (SV) on GGA27 leads to an altered expression of the gene HOXB8. This Mb allele was shown to be completely associated with the Mb phenotype in nine other independent Mb chicken breeds. The Mb allele differs from the wild-type mb allele by three duplications, one in tandem and two that are translocated to that of the tandem repeat around 1.70 Mb on GGA27. The duplications contain total seven annotated genes and their expression was tested during distinct stages of Mb morphogenesis. A continuous high ectopic expression of HOXB8 was found in the facial skin of Mb chickens, strongly suggesting that HOXB8 directs this regional feather-development. In conclusion, our results provide an interesting example of how genomic structural rearrangements alter the regulation of genes leading to novel phenotypes. Further, it again illustrates the value of utilizing derived phenotypes in domestic animals to dissect the genetic basis of developmental traits, herein providing novel insights into the likely role of HOXB8 in feather development and differentiation.

Genetic variation is a key part for the study of evolution, development and differentiation. In domestic animals, many breeds display striking phenotypes that differentiate them from their wild ancestors. Several of these have been related to structural variations, including Fibromelanosis and Rose-comb in chickens, Double-muscled and Osteopetrosis in cattle, Cone degeneration in dogs, and White coat color in pigs. The feather is a type of skin appendages that exists in multiple variants on different body parts, and the derived feathering phenotypes in domestic birds are perfect resources to decipher the mechanisms regulating feather development and differentiation. Here we study the genetics of the Muffs and beard trait, a variant that alters the feather development in the facial area of chickens. We show that this phenotype is associated with a genomic structural variant that leads to an ectopic expression of HOXB8 in the facial skin during feather development. This is thus another example of how structural variants in the genome lead to novel, derived phenotypic changes in domestic animals and suggests an important role for HOXB8 in feather development.

Zinc Finger Homeodomain Factor Zfhx3 Is Essential for Mammary Lactogenic Differentiation by Maintaining Prolactin Signaling Activity

The zinc finger homeobox 3 (ZFHX3, also named ATBF1 for AT motif binding factor 1) is a transcription factor that suppresses prostatic carcinogenesis and induces neuronal differentiation. It also interacts with estrogen receptor α to inhibit cell proliferation and regulate pubertal mammary gland development in mice. In the present study, we examined whether and how Zfhx3 regulates lactogenic differentiation in mouse mammary glands. At different stages of mammary gland development, Zfhx3 protein was expressed at varying levels, with the highest level at lactation. In the HC11 mouse mammary epithelial cell line, an in vitro model of lactogenesis, knockdown of Zfhx3 attenuated prolactin-induced β-casein expression and morphological changes, indicators of lactogenic differentiation. In mouse mammary tissue, knock-out of Zfhx3 interrupted lactogenesis, resulting in underdeveloped glands with much smaller and fewer alveoli, reduced β-casein expression, accumulation of large cytoplasmic lipid droplets in luminal cells after parturition, and failure in lactation. Mechanistically, Zfhx3 maintained the expression of Prlr (prolactin receptor) and Prlr-Jak2-Stat5 signaling activity, whereas knockdown and knock-out of Zfhx3 in HC11 cells and mammary tissues, respectively, decreased Prlr expression, Stat5 phosphorylation, and the expression of Prlr-Jak2-Stat5 target genes. These findings indicate that Zfhx3 plays an essential role in proper lactogenic development in mammary glands, at least in part by maintaining Prlr expression and Prlr-Jak2-Stat5 signaling activity.

The homeoprotein DLX3 and tumor suppressor p53 co-regulate cell cycle progression and squamous tumor growth

Epidermal homeostasis depends on the coordinated control of keratinocyte cell cycle. Differentiation and the alteration of this balance can result in neoplastic development. Here we report on a novel DLX3-dependent network that constrains epidermal hyperplasia and squamous tumorigenesis. By integrating genetic and transcriptomic approaches, we demonstrate that DLX3 operates through a p53-regulated network. DLX3 and p53 physically interact on the p21 promoter to enhance p21 expression. Elevating DLX3 in keratinocytes produces a G1-S blockade associated with p53 signature transcriptional profiles. In contrast, DLX3 loss promotes a mitogenic phenotype associated with constitutive activation of ERK. DLX3 expression is lost in human skin cancers and is extinguished during progression of experimentally induced mouse squamous cell carcinoma (SCC). Reinstatement of DLX3 function is sufficient to attenuate the migration of SCC cells, leading to decreased wound closure. Our data establish the DLX3-p53 interplay as a major regulatory axis in epidermal differentiation and suggest that DLX3 is a modulator of skin carcinogenesis.

Homeobox B7 promotes the osteogenic differentiation potential of mesenchymal stem cells by activating RUNX2 and transcript of BSP

Mesenchymal stem cells (MSCs) are a reliable cell source for tissue regeneration. However, the molecular mechanisms underlying the directed differentiation of MSCs remain unclear; thus, their use is limited. Here, we investigate HOXB7 function in the osteogenic differentiation potentials of MSCs using stem cells from apical papilla (SCAPs) and bone marrow stem cells (BMSCs). The HOXB7 gene is highly expressed in BMSCs compared with dental tissue-derived MSCs. We found that, in vitro, over-expression of HOXB7 in SCAPs enhanced alkaline phosphatase (ALP) activity and mineralization. HOXB7 over-expression affected the mRNA expression of osteonectin (ON), collagen alpha-2(I) chain (COL1A2), bone sialoprotein (BSP), and osteocalcin (OCN), led to the expression of the key transcription factor, runt-related transcription factor 2 (RUNX2), and promoted SCAP osteogenic differentiation in vitro. The knock-down of HOXB7 inhibited ALP activity, mineralization, and the expression of ON, BSP, COL1A2, OCN, and RUNX2 in BMSCs in vitro. In addition, transplant experiments in nude mice confirmed that SCAP osteogenesis was triggered when HOXB7 was activated. Furthermore, Over-expression of HOXB7 significantly increased the levels of HOXB7 associated with the BSP promoter by ChIP assays. Taken together, these results indicate that HOXB7 enhances SCAP osteogenic differentiation by up-regulating RUNX2 and directly activating transcript of BSP. Thus, the activation of HOXB7 signaling might improve tissue regeneration mediated by MSCs. These results provide insight into the mechanism underlying the directed differentiation of MSCs.