Calcineurin initiates smooth muscle differentiation in neural crest stem cells

The process of vascular smooth muscle cell (vSMC) differentiation is critical to embryonic angiogenesis. However, despite its importance, the vSMC differentiation program remains largely undefined. Murine gene disruption studies have identified several gene products that are necessary for vSMC differentiation, but these methodologies cannot establish whether or not a factor is sufficient to initiate the differentiation program. A gain-of-function system consisting of normal vSMC progenitor cells would serve as a useful complement to whole animal loss-of-function studies. We use such a system here, namely freshly isolated rat neural crest stem cells (NCSCs), to show that activation of the calcineurin signaling pathway is sufficient to drive these cells toward a smooth muscle fate. In addition, we present data suggesting that transforming growth factor (TGF)-β1, which also causes NCSCs to differentiate into smooth muscle, activates calcineurin signaling in NCSCs, leading to a model in which activation of calcineurin signaling is the mechanism by which TGF-β1 causes SMC differentiation in these cells

sodC-Based Real-Time PCR for Detection of Neisseria meningitidis

Real-time PCR (rt-PCR) is a widely used molecular method for detection of Neisseria meningitidis (Nm). Several rt-PCR assays for Nm target the capsule transport gene, ctrA. However, over 16% of meningococcal carriage isolates lack ctrA, rendering this target gene ineffective at identification of this sub-population of meningococcal isolates. The Cu-Zn superoxide dismutase gene, sodC, is found in Nm but not in other Neisseria species. To better identify Nm, regardless of capsule genotype or expression status, a sodC-based TaqMan rt-PCR assay was developed and validated. Standard curves revealed an average lower limit of detection of 73 genomes per reaction at cycle threshold (Ct) value of 35, with 100% average reaction efficiency and an average R2 of 0.9925. 99.7% (624/626) of Nm isolates tested were sodC-positive, with a range of average Ct values from 13.0 to 29.5. The mean sodC Ct value of these Nm isolates was 17.6±2.2 (±SD). Of the 626 Nm tested, 178 were nongroupable (NG) ctrA-negative Nm isolates, and 98.9% (176/178) of these were detected by sodC rt-PCR. The assay was 100% specific, with all 244 non-Nm isolates testing negative. Of 157 clinical specimens tested, sodC detected 25/157 Nm or 4 additional specimens compared to ctrA and 24 more than culture. Among 582 carriage specimens, sodC detected Nm in 1 more than ctrA and in 4 more than culture. This sodC rt-PCR assay is a highly sensitive and specific method for detection of Nm, especially in carriage studies where many meningococcal isolates lack capsule genes

Aryl Hydrocarbon Receptor Activation by TCDD Reduces Inflammation Associated with Crohn's Disease

Crohn's disease results from a combination of genetic and environmental factors that trigger an inappropriate immune response to commensal gut bacteria. The aryl hydrocarbon receptor (AhR) is well known for its involvement in the toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), an environmental contaminant that affects people primarily through the diet. Recently, TCDD was shown to suppress immune responses by generating regulatory T cells (Tregs). We hypothesized that AhR activation dampens inflammation associated with Crohn's disease. To test this hypothesis, we utilized the 2,4,6-trinitrobenzenesulfonic acid (TNBS) murine model of colitis. Mice were gavaged with TCDD prior to colitis induction with TNBS. Several parameters were examined including colonic inflammation via histological and flow cytometric analyses. TCDD-treated mice recovered body weight faster and experienced significantly less colonic damage. Reduced levels of interleukin (IL) 6, IL-12, interferon-gamma, and tumor necrosis factor-α demonstrated suppression of inflammation in the gut following TCDD exposure. Forkhead box P3 (Foxp3)egfp mice revealed that TCDD increased the Foxp3+ Treg population in gut immune tissue following TNBS exposure. Collectively, these results suggest that activation of the AhR by TCDD decreases colonic inflammation in a murine model of colitis in part by generating regulatory immune cells. Ultimately, this work may lead to the development of more effective therapeutics for the treatment of Crohn's disease

Applied Genomics: Data Mining Reveals Species-Specific Malaria Diagnostic Targets More Sensitive than 18S rRNA▿†‡

Accurate and rapid diagnosis of malaria infections is crucial for implementing species-appropriate treatment and saving lives. Molecular diagnostic tools are the most accurate and sensitive method of detecting Plasmodium, differentiating between Plasmodium species, and detecting subclinical infections. Despite available whole-genome sequence data for Plasmodium falciparum and P. vivax, the majority of PCR-based methods still rely on the 18S rRNA gene targets. Historically, this gene has served as the best target for diagnostic assays. However, it is limited in its ability to detect mixed infections in multiplex assay platforms without the use of nested PCR. New diagnostic targets are needed. Ideal targets will be species specific, highly sensitive, and amenable to both single-step and multiplex PCRs. We have mined the genomes of P. falciparum and P. vivax to identify species-specific, repetitive sequences that serve as new PCR targets for the detection of malaria. We show that these targets (Pvr47 and Pfr364) exist in 14 to 41 copies and are more sensitive than 18S rRNA when utilized in a single-step PCR. Parasites are routinely detected at levels of 1 to 10 parasites/μl. The reaction can be multiplexed to detect both species in a single reaction. We have examined 7 P. falciparum strains and 91 P. falciparum clinical isolates from Tanzania and 10 P. vivax strains and 96 P. vivax clinical isolates from Venezuela, and we have verified a sensitivity and specificity of ∼100% for both targets compared with a nested 18S rRNA approach. We show that bioinformatics approaches can be successfully applied to identify novel diagnostic targets and improve molecular methods for pathogen detection. These novel targets provide a powerful alternative molecular diagnostic method for the detection of P. falciparum and P. vivax in conventional or multiplex PCR platforms