TWIST1 interacts with ß/δ-catenins during neural tube development and regulates fate transition in cranial neural crest cells.

Cell fate determination is a necessary and tightly regulated process for producing different cell types and structures during development. Cranial neural crest cells (CNCCs) are unique to vertebrate embryos and emerge from the neural plate borders into multiple cell lineages that differentiate into bone, cartilage, neurons and glial cells. We have previously reported that Irf6 genetically interacts with Twist1 during CNCC-derived tissue formation. Here, we have investigated the mechanistic role of Twist1 and Irf6 at early stages of craniofacial development. Our data indicate that TWIST1 is expressed in endocytic vesicles at the apical surface and interacts with ß/δ-catenins during neural tube closure, and Irf6 is involved in defining neural fold borders by restricting AP2α expression. Twist1 suppresses Irf6 and other epithelial genes in CNCCs during the epithelial-to-mesenchymal transition (EMT) process and cell migration. Conversely, a loss of Twist1 leads to a sustained expression of epithelial and cell adhesion markers in migratory CNCCs. Disruption of TWIST1 phosphorylation in vivo leads to epidermal blebbing, edema, neural tube defects and CNCC-derived structural abnormalities. Altogether, this study describes a previously uncharacterized function of mammalian Twist1 and Irf6 in the neural tube and CNCCs, and provides new target genes for Twist1 that are involved in cytoskeletal remodeling.

Systematic review of hormonal and genetic factors involved in the nonsyndromic disorders of the lower jaw.

Mandibular disorders are among the most common birth defects in humans, yet the etiological factors are largely unknown. Most of the neonates affected by mandibular abnormalities have a sequence of secondary anomalies, including airway obstruction and feeding problems, that reduce the quality of life. In the event of lacking corrective surgeries, patients with mandibular congenital disorders suffer from additional lifelong problems such as sleep apnea and temporomandibular disorders, among others. The goal of this systematic review is to gather evidence on hormonal and genetic factors that are involved in signaling pathways and interactions that are potentially associated with the nonsyndromic mandibular disorders. We found that members of FGF and BMP pathways, including FGF8/10, FGFR2/3, BMP2/4/7, BMPR1A, ACVR1, and ACVR2A/B, have a prominent number of gene-gene interactions among all identified genes in this review. Gene ontology of the 154 genes showed that the functional gene sets are involved in all aspects of cellular processes and organogenesis. Some of the genes identified by the genome-wide association studies of common mandibular disorders are involved in skeletal formation and growth retardation based on animal models, suggesting a potential direct role as genetic risk factors in the common complex jaw disorders. Developmental Dynamics 248:162-172, 2019. © 2018 Wiley Periodicals, Inc.

Allele-specific epigenome maps reveal sequence-dependent stochastic switching at regulatory loci.

To assess the impact of genetic variation in regulatory loci on human health, we constructed a high-resolution map of allelic imbalances in DNA methylation, histone marks, and gene transcription in 71 epigenomes from 36 distinct cell and tissue types from 13 donors. Deep whole-genome bisulfite sequencing of 49 methylomes revealed sequence-dependent CpG methylation imbalances at thousands of heterozygous regulatory loci. Such loci are enriched for stochastic switching, which is defined as random transitions between fully methylated and unmethylated states of DNA. The methylation imbalances at thousands of loci are explainable by different relative frequencies of the methylated and unmethylated states for the two alleles. Further analyses provided a unifying model that links sequence-dependent allelic imbalances of the epigenome, stochastic switching at gene regulatory loci, and disease-associated genetic variation.

Mandibular Explant Assay for Investigating Extrinsic Stimuli on Bone and Cartilage Development.

A major issue in developmental biology is to determine how embryonic tissues respond to molecular signals in a timely manner and given the position-restricted instructions during morphogenesis, of which Meckel's cartilage is a classical example. The ex-vivo explant model is a practical and convenient system that allows investigation of bone and cartilage responses to specific stimuli under a controlled manner that closely mimics the in vivo conditions. In this protocol, the explant model was applied to test whether Meckel's cartilage and surrounding tissues are responsive to the Endothelin1 (Edn1) signaling molecule and whether it would rescue the phenotype of genetic mutations. The system allows a high degree of manipulation in terms of the concentrations of exogenous compounds added to the explant, time points with regards to measuring mandibular development, and the method of application of exogenous molecules and teratogens.

Antiviral activity of fractions from leaves of Piper regnelli var. pallescens

This study investigated the antiviral potential of fractions and eupomatenoid-5 obtained from Piper regnelli (Miq.) C. DC., Piperaceae, leaves against bovine herpesvirus-1 (BHV-1) and poliovirus. VERO cell monolayers in 96-well cell culture plates were infected with BHV-1 or poliovirus and incubated in the presence and absence of samples for 48 h. The cells were then fixed and stained with sulforhodamine B, and the virus-induced cytopathic effect was measured in a 96-well plate reader at 530 nm. Cytotoxicity was assessed by incubating the cell monolayers with samples for 72 h. The hexane, chloroform, chloroform/ethyl acetate (19:1), and chloroform/ethyl acetate (9:1) fractions showed activity against BHV-1. The chloroform, chloroform/ethyl acetate (19:1), chloroform/ethyl acetate (9:1), chloroform/ethyl acetate (1:1), and ethyl acetate fractions were active against poliovirus. The chloroform/ethyl acetate (9:1) fraction presented the best selectivity index for both viruses. The present study reports the antiviral activity of the extract and fractions of P. regnelli leaves.