Identification of the Toxoplasma gondii mitochondrial ribosome, and characterisation of a protein essential for mitochondrial translation

Apicomplexan parasites cause diseases such as malaria and toxoplasmosis. The apicomplexan mitochondrion shows striking differences from common model organisms, including fundamental processes such as mitochondrial translation. Despite evidence that mitochondrial translation is essential for parasite survival, it is largely understudied. Progress has been restricted by the absence of functional assays to detect apicomplexan mitochondrial translation, a lack of knowledge of proteins involved in the process and the inability to identify and detect mitoribosomes. We report the localization of 12 new mitochondrial proteins, including 6 putative mitoribosomal proteins. We demonstrate the integration of three mitoribosomal proteins in macromolecular complexes, and provide evidence suggesting these are apicomplexan mitoribosomal subunits, detected here for the first time. Finally, a new analytical pipeline detected defects in mitochondrial translation upon depletion of the small subunit protein 35 (TgmS35), while other mitochondrial functions remain unaffected. Our work lays a foundation for the study of apicomplexan mitochondrial translation

Angiogenesis in Paget's Disease of the Vulva and the Breast: Correlation with Microvessel Density

Our understanding of the pathogenesis of Paget's disease of the vulva and the breast remains limited. Current evidence supports the fact that angiogenesis plays an important role in the pathogenesis of several diseases. Therefore, we sought to define its role, as correlated with microvessel density, in Paget's disease of the vulva and the breast. Microvessels were analysed using anti-von Willebrand factor antibody in 105 cases of Paget's disease of the vulva and the breast comprising 71 cases of Paget's disease of the vulva, including 8 cases with invasive disease, and 34 cases of Paget's disease of the breast. The latter included 12 cases with DCIS, 5 cases with both DCIS and invasive carcinoma, and 6 with carcinoma alone. Eleven cases had no underlying tumour identified. Increased microvessel density was demonstrated in Paget's disease of the breast with DCIS and with carcinoma alone compared to Paget's disease of the breast alone, P < 0.08 and P < 0.013, respectively. There were no significant differences in microvessel density in the vulval cases. Neovascularisation is an important process in the development of Paget's disease of the breast. Other biological and molecular processes are more involved in the pathogenesis of Paget's disease of the vulva

Sex-dependent changes in right ventricular gene expression in response to pressure overload in a rat model of pulmonary trunk banding

Right ventricular hypertrophy (RVH) and subsequent failure are consequences of pulmonary arterial hypertension (PAH). While females are four times more likely to develop PAH, male patients have poorer survival even with treatment, suggesting a sex-dependent dimorphism in right ventricular (RV) hypertrophy/compensation. This may result from differential gene expression in the RV in male vs. female. To date, the sex dependent effect of pressure overload on RV function and changes in gene expression is still unclear. We hypothesize that pressure overload promotes gene expression changes in the RV that may contribute to a poorer outcome in males vs. females. To test this hypothesis, male and female Wistar rats underwent either a sham procedure (sham controls) or moderate pulmonary trunk banding (PTB) (a model of pressure overload induced compensated RV hypertrophy) surgery. Seven weeks post-surgery, RV function was assessed in vivo, and tissue samples were collected for gene expression using qPCR. Compared to sham controls, PTB induced significant increases in the right ventricular systolic pressure, the filling pressure and contractility, which were similar between male and female rats. PTB resulted in an increase in RVH indexes (RV weight, RV weight/tibia length and Fulton index) in both male and female groups. However, RVH indexes were significantly higher in male-PTB when compared to female-PTB rats. Whilst end of procedure body weight was greater in male rats, end of procedure pulmonary artery (PA) diameters were the same in both males and females. RV gene expression analysis revealed that the following genes were increased in PTB-male rats compared with the sham-operated controls: natriuretic peptide A (ANP) and B (BNP), as well as the markers of fibrosis; collagen type I and III. In females, only BNP was significantly increased in the RV when compared to the sham-operated female rats. Furthermore, ANP, BNP and collagen III were significantly higher in the RV from PTB-males when compared to RV from PTB-female rats. Our data suggest that pressure overload-mediated changes in gene expression in the RV from male rats may worsen RVH and increase the susceptibility of males to a poorer outcome when compared to females

Family presence during resuscitation: A randomised controlled trial of the impact of family presence

Introduction: This study was undertaken to determine effects on relatives of family presence in an emergency resuscitation room during resuscitation. Methods: This study was undertaken using a randomised controlled trial using survey methodology. The setting of the study was the emergency department of a major tertiary referral teaching hospital in Queensland. Participants were relatives over 18 years of age, related to patients meeting the inclusion criteria. Relatives were randomly assigned to the experimental or control group. The control group followed the established procedure of placement in the relatives' waiting room, while the experimental group was given the option to be present during the resuscitation with a supportive officer for assistance. Results: An association was found between those who were present (and their relative survived) and their belief that their presence was beneficial to the patient. Demographic data identified characteristics of the relatives. Conclusions: This work has identified that relatives find it beneficial to be present in the resuscitation room. Their presence helped with communication between staff and family, and helped relatives to cope with the situation

Mutations in UBA3 Confer Resistance to the NEDD8-Activating Enzyme Inhibitor MLN4924 in Human Leukemic Cells

The NEDD8-activating enzyme (NAE) initiates neddylation, the cascade of post-translational NEDD8 conjugation onto target proteins. MLN4924, a selective NAE inhibitor, has displayed preclinical anti-tumor activity in vitro and in vivo, and promising clinical activity has been reported in patients with refractory hematologic malignancies. Here, we sought to understand the mechanisms of resistance to MLN4924. K562 and U937 leukemia cells were exposed over a 6 month period to MLN4924 and populations of resistant cells (R-K562MLN, R-U937MLN) were selected. R-K562MLN and R-U937MLN cells contain I310N and Y352H mutations in the NAE catalytic subunit UBA3, respectively. Biochemical analyses indicate that these mutations increase the enzyme’s affinity for ATP while decreasing its affinity for NEDD8. These mutations effectively contribute to decreased MLN4924 potency in vitro while providing for sufficient NAE function for leukemia cell survival. Finally, R-K562MLN cells showed cross-resistance to other NAE-selective inhibitors, but remained sensitive to a pan-E1 (activating enzyme) inhibitor. Thus, our work provides insight into mechanisms of MLN4924 resistance to facilitate the development of more effective second-generation NAE inhibitors

Gene expression in lungs of mice lacking the 5-hydroxytryptamine transporter gene

<p>Abstract</p> <p>Background</p> <p>While modulation of the serotonin transporter (5HTT) has shown to be a risk factor for pulmonary arterial hypertension for almost 40 years, there is a lack of in vivo data about the broad molecular effects of pulmonary inhibition of 5HTT. Previous studies have suggested effects on inflammation, proliferation, and vasoconstriction. The goal of this study was to determine which of these were supported by alterations in gene expression in serotonin transporter knockout mice.</p> <p>Methods</p> <p>Eight week old normoxic mice with a 5-HTT knock-out (5HTT-/-) and their heterozygote(5HTT+/-) or wild-type(5HTT+/+) littermates had right ventricular systolic pressure(RVSP) assessed, lungs collected for RNA, pooled, and used in duplicate in Affymetrix array analysis. Representative genes were confirmed by quantitative RT-PCR and western blot.</p> <p>Results</p> <p>RVSP was normal in all groups. Only 124 genes were reliably changed between 5HTT-/- and 5HTT+/+ mice. More than half of these were either involved in inflammatory response or muscle function and organization; in addition, some matrix, heme oxygenase, developmental, and energy metabolism genes showed altered expression. Quantitative RT-PCR for examples from each major group confirmed changes seen by array, with an intermediate level in 5HTT +/- mice.</p> <p>Conclusion</p> <p>These results for the first time show the in vivo effects of 5HTT knockout in lungs, and show that many of the downstream mechanisms suggested by cell culture and ex vivo experiments are also operational in vivo. This suggests that the effect of 5HTT on pulmonary vascular function arises from its impact on several systems, including vasoreactivity, proliferation, and immune function.</p