In this study, we identify gene targets and cellular events mediating the teratogenic action(s) of 5-Aza-2′-deoxycytidine (AzaD), an inhibitor of DNA methylation, on secondary palate development. Exposure of pregnant mice (on gestation day (GD) 9.5) to AzaD for 12 hrs resulted in the complete penetrance of cleft palate (CP) in fetuses. Analysis of cells of the embryonic first branchial arch (1-BA), in fetuses exposed to AzaD, revealed: 1) significant alteration in expression of genes encoding several morphogenetic factors, cell cycle inhibitors and regulators of apoptosis; 2) a decrease in cell proliferation; and, 3) an increase in apoptosis. Pyrosequencing of selected genes, displaying pronounced differential expression in AzaD-exposed 1-BAs, failed to reveal significant alterations in CpG methylation levels in their putative promoters or gene bodies. CpG methylation analysis suggested that the effects of AzaD on gene expression were likely indirect.

No abstract

p300 is a multifunctional transcriptional coactivator that interacts with numerous transcription factors and exhibits protein/histone acetyltransferase activity. Loss of p300 function in humans and in mice leads to craniofacial defects. In this study, we demonstrated that inhibition of p300 histone acetyltransferase activity with the compound, C646, altered the expression of several genes, including Cdh1 (E-cadherin) in mouse maxillary mesenchyme cells, which are the cells that give rise to the secondary palate. The increased expression of plasma membrane-bound E-cadherin was associated with reduced cytosolic β-catenin, that led to attenuated signaling through the canonical Wnt pathway. Furthermore, C646 reduced both cell proliferation and the migratory ability of these cells. These results suggest that p300 histone acetyltransferase activity is critical for Wnt-dependent palate mesenchymal cell proliferation and migration, both processes that play a significant role in morphogenesis of the palate.

Hyperhomocysteinemia (HHcy) affects bone remodeling since destructive process in cortical alveolar bone has been linked with it, however; the mechanism remains at large. HHcy increases pro-inflammatory cytokines viz. TNF-α, IL-1b, IL-6 and IL-8 that leads to a cascade that negatively impacts methionine-metabolism and homocysteine cycling. Further, chronic inflammation decreases vitamins B12, B6 and folic acid that are required for methionine-homocysteine homeostasis. This study aims to investigate a HHcy mouse model (cystathionine β-synthase deficient; CBS+/-) for studying the potential pathophysiological changes, if any, in the periodontium (gingiva, periodontal ligament, cement and alveolar bone). We compared periodontium, side-by-side; CBS+/- model with that of wild-type; WT (C57BL/6J) mice. Histology and histomorphometry of mandibular bone along with gene expression analyses were carried out. Also, pro-angiogenic proteins and metalloproteinases were studied. To our knowledge, this research shows, for the first time, a direct connection between periodontal disease during CBS deficiency thereby suggesting the existence of disease drivers during hyperhomocysteinemic condition. Our findings offer opportunities to develop diagnostics/therapeutics for the people who suffer from chronic metabolic disorders like HHcy.

During acute heart failure (HF), remote ischemic conditioning (RIC) has proven to be beneficial; however, it is currently unclear whether it also extends benefits from chronic congestive, cardiopulmonary heart failure (CHF). Previous studies from our laboratory have shown three phases describing CHF viz. (1) HF with preserved ejection fraction (HFpEF), (2) HF with reduced EF (HFrEF), and (3) HF with reversed EF. Although reciprocal organ interaction, ablation of sympathetic, and calcium signaling genes are associated with HFpEF to HFrEF, the mechanism is unclear. The HFrEF ensues, in part, due to reduced angiogenesis, coronary reserve, and leakage of endocardial endothelial (EE) and finally breakdown of the blood-heart barrier (BHB) integrity. In fact, our hypothesis states that a change in phenotype from compensatory HFpEF to decompensatory HFrEF is determined by a potential decrease in regenerative, proangiogenic factors along with a concomitant increase in epigenetic memory, inflammation that combinedly causes oxidative, and proteolytic stress response. To test this hypothesis, we created CHF by aorta-vena-cava (AV) fistula in a group of mice that were subsequently treated with that of hind-limb RIC. HFpEF vs. HFrEF transition was determined by serial/longitudinal echo measurements. Results revealed an increase in skeletal muscle musclin contents, bone-marrow (CD71), and sympathetic activation (β2-AR) by RIC. We also observed a decrease in vascular density and attenuation of EE-BHB function due to a corresponding increase in the activity of MMP-2, vascular endothelial growth factor (VEGF), caspase, and calpain. This decrease was successfully mitigated by RIC-released skeletal muscle exosomes that contain musclin, the myokine along with bone marrow, and sympathetic activation. In short, based on proteome (omics) analysis, ∼20 proteins that appear to be involved in signaling pathways responsible for the synthesis, contraction, and relaxation of cardiac muscle were found to be the dominant features. Thus, our results support that the CHF phenotype causes dysfunction of cardiac metabolism, its contraction, and relaxation. Interestingly, RIC was able to mitigate many of the deleterious changes, as revealed by our multi-omics findings.