Diverse signaling cues and attendant proteins work together during organogenesis, including craniofacial development. Lip and palate formation starts as early as the fourth week of gestation in humans or embryonic day 9.5 in mice. Disruptions in these early events may cause serious consequences, such as orofacial clefts, mainly cleft lip and/or cleft palate. Morphogenetic Wnt signaling, along with other signaling pathways and transcription regulation mechanisms, plays crucial roles during embryonic development, yet the signaling mechanisms and interactions in lip and palate formation and fusion remain poorly understood. Various Wnt signaling and related genes have been associated with orofacial clefts. This Review discusses the role of Wnt signaling and its crosstalk with cell adhesion molecules, transcription factors, epigenetic regulators and other morphogenetic signaling pathways, including the Bmp, Fgf, Tgfβ, Shh and retinoic acid pathways, in orofacial clefts in humans and animal models, which may provide a better understanding of these disorders and could be applied towards prevention and treatments.

Background -The pathogenesis of canine atopic dermatitis (AD) is complex. Dysregulation of the cutaneous immune system is considered to be an important part of the allergic response. Exploration of association of interleukin-17 (IL-17), IL-31, IgE and leukogram attributes with canine AD could provide novel insights into its immunopathology.Hypothesis/Objectives -To investigate possible associations of IL-17, IL-3, IgE and leukogram attributes of canine AD.Animals -17 dogs diagnosed with AD and six healthy dogs.Methods and materials -Circulating concentrations of IL-17, IL-31 and total IgE from sera samples were determined using commercial canine-specific quantitative immunoassay kits. Complete blood cell counts were analysed by an automated haematology analyser. Statistical differences between the two groups were determined using an unpaired t-test. The degree of relationship between the IL-17, IL-31, IgE, total leukocyte count (TLC) values and clinical signs scores (Canine Atopic Dermatitis Lesion Index and pruritus Visual Analog Scale pVAS) was determined by Pearson's r correlation statistic.Results -Dogs with AD had significantly (P < 0.0001) higher circulating concentrations of IL-17, IL-31 and total IgE compared with healthy dogs. Dogs with AD also had significantly higher TLC (P < 0.0002), absolute neutrophils (P < 0.0001) and absolute eosinophils (P < 0.0001) counts, and percentage of neutrophils (P < 0.03) and eosinophils (P < 0.0001) compared with healthy controls. A significant positive correlation (r 2 = 0.396; P < 0.007) between the pVAS and IL-31 was observed in dogs with AD.Conclusions and clinical importance -Marked elevation in circulating IL-17, IL-31 and total IgE along with the abnormalities in leukogram may be associated with canine AD and could be possible targets in the therapeutic management of canine AD.

Demodex canis infestation in dogs remains one of the main challenges in veterinary dermatology. The exact pathogenesis of canine demodicosis is unknown but an aberration in immune status is considered very significant. No studies have underpinned the nexus between induction of demodicosis and neural immunosuppressive pathways so far. We have evaluated the involvement of cholinergic pathways in association with cytokines regulation as an insight into the immuno-pathogenesis of canine demodicosis in the present study. Remarkable elevations in circulatory immunosuppressive cytokine interleukin-10 and cholinesterase activity were observed in dogs with demodicosis. Simultaneously, remarkable reduction in circulatory pro-inflammatory cytokine tumour necrosis factor-alpha level was observed in dogs with demodicosis. Findings of the present study evidently suggest that Demodex mites might be affecting the cholinergic pathways to induce immunosuppression in their host and then proliferate incessantly in skin microenvironment to cause demodicosis.

Two-component systems, comprising histidine kinases and response regulators, empower bacteria to sense and adapt to diverse environmental stresses. Some histidine kinases are bifunctional; their phosphorylation (kinase) and dephosphorylation (phosphatase) activities toward their cognate response regulators permit the rapid reversal of genetic responses to an environmental stimulus. DevR-DevS/DosR-DosS is one of the bestcharacterized two-component systems of Mycobacterium tuberculosis. The kinase function of DevS is activated by gaseous stress signals, including hypoxia, resulting in the induction of~48-genes DevR dormancy regulon. Regulon expression is tightly controlled and lack of expression in aerobic Mtb cultures is ascribed to the absence of phosphorylated DevR. Here we show that DevS is a bifunctional sensor and possesses a robust phosphatase activity toward DevR. We used site-specific mutagenesis to generate substitutions in conserved residues in the dimerization and histidine phosphotransfer domain of DevS and determined their role in kinase/phosphatase functions. In vitro and in vivo experiments, including a novel in vivo phosphatase assay, collectively establish that these conserved residues are critical for regulating kinase/phosphatase functions. Our findings establish DevS phosphatase function as an effective control mechanism to block aerobic expression of the DevR dormancy regulon. Asp-396 is essential for both kinase and phosphatase functions, whereas Gln-400 is critical for phosphatase function. The positive and negative functions perform opposing roles in DevS: the kinase function triggers regulon induction under hypoxia, whereas its phosphatase function prevents expression under aerobic conditions. A finely tuned balance in these opposing activities calibrates the dormancy regulon response output.

In India, as in other parts of the world, nonsyndromic cleft lip with or without cleft palate (NSCL +/- P) is a highly prevalent birth defect, its incidence in males being twice that in females. A case-control association study has been carried out with respect to homocysteine level and MTHFR C677T, A1298C and SLC19A1 (RFC1) G80A genotypes from an eastern Indian cohort to investigate whether Hcy and other Hcy-pathway genes also contribute to the risk level. While MTHFR 677T and SLC19A1 80G are individually and cumulatively risk factors, SLC19A1 80A appears to be protective against MTHFR 677T risk allele. Elevated Hcy associates with NSCL +/- P both in case mothers and cases. Significantly, this difference shows a gender bias: the level of elevation of Hcy in female cases is distinctly higher than in males, and more case females are hyperhomocyteinemic than the case males. It implies that compared with the males, higher level of Hcy is needed for NSCL +/- P to manifest in the females. We consider this as one of the possible factors why the incidence of this disorder in females is much lower than in males.

Genome-wide association studies for non-syndromic orofacial clefting (OFC) have identified single nucleotide polymorphisms (SNPs) at loci where the presumed risk-relevant gene is expressed in oral periderm. The functional subsets of such SNPs are difficult to predict because the sequence underpinnings of periderm enhancers are unknown. We applied ATAC-seq to models of human palate periderm, including zebrafish periderm, mouse embryonic palate epithelia, and a human oral epithelium cell line, and to complementary mesenchymal cell types. We identified sets of enhancers specific to the epithelial cells and trained gapped-kmer support-vector-machine classifiers on these sets. We used the classifiers to predict the effects of 14 OFC-associated SNPs at 12q13 near KRT18. All the classifiers picked the same SNP as having the strongest effect, but the significance was highest with the classifier trained on zebrafish periderm. Reporter and deletion analyses support this SNP as lying within a periderm enhancer regulating KRT18/KRT8 expression.

Mycobacterium tuberculosis (Mtb) owes its success as a pathogen in large measure to its ability to exist in a persistent state of 'dormancy' resulting in a lifelong latent tuberculosis (TB) infection. An understanding of bacterial adaptation during dormancy will help in devising approaches to counter latent TB infection. In vitro models have provided valuable insights into bacterial adaptation; however, they have limitations because they do not disclose the bacterial response to the intracellular environment wherein the bacteria are simultaneously exposed to multiple stresses. We describe the pleiotropic response of Mtb in the vitamin C (vit C) model of dormancy developed in our laboratory. Vit C mediates a rapid regulation of genes representing~14 % of the genome in Mtb cultures. The upregulated genes were better represented in lipid, intermediary metabolism and regulatory protein categories. The downregulated genes mainly related to virulence, detoxification, information pathways and cell wall processes. A comparison of this response to that in other models indicates that vit C generates a multiple-stress environment for axenic Mtb cultures that resembles a macrophage-like environment. The bacterial response to vit C resembles responses to gaseous stresses such as hypoxia and nitric oxide, oxidative and nitrosative stresses, nutrient starvation and, notably, the activated macrophage environment itself. These responses demonstrate that the influence of vit C on Mtb gene expression extends well beyond the DevR dormancy regulon. A detailed characterization of the response to vit C is expected to disclose useful strategies to counter the adaptive mechanisms essential to Mtb dormancy.

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