Plakoglobin regulates adipocyte differentiation independently of the Wnt/ß-catenin signaling pathway.

The scaffold protein 14-3-3ζ is an established regulator of adipogenesis and postnatal adiposity. We and others have demonstrated the 14-3-3ζ interactome to be diverse and dynamic, and it can be examined to identify novel regulators of physiological processes, including adipogenesis. In the present study, we sought to determine if factors that influence adipogenesis during the development of obesity could be identified in the 14-3-3ζ interactome found in white adipose tissue of lean or obese TAP-tagged-14-3-3ζ overexpressing mice. Using mass spectrometry, differences in the abundance of novel, as well as established, adipogenic factors within the 14-3-3ζ interactome could be detected in adipose tissues. One novel candidate was revealed to be plakoglobin, the homolog of the known adipogenic inhibitor, ß-catenin, and herein, we report that plakoglobin is involved in adipocyte differentiation. Plakoglobin is expressed in murine 3T3-L1 cells and is primarily localized to the nucleus, where its abundance decreases during adipogenesis. Depletion of plakoglobin by siRNA inhibited adipogenesis and reduced PPARγ2 expression, and similarly, plakoglobin depletion in human adipose-derived stem cells also impaired adipogenesis and reduced lipid accumulation post-differentiation. Transcriptional assays indicated that plakoglobin does not participate in Wnt/ß-catenin signaling, as its depletion did not affect Wnt3a-mediated transcriptional activity. Taken together, our results establish plakoglobin as a novel regulator of adipogenesis in vitro and highlights the ability of using the 14-3-3ζ interactome to identify potential pro-obesogenic factors.

[Impact of exhaled CO measurement. A randomised study among 578 smoking patients in general practice]. / Evaluation de l'impact de la mesure du monoxyde de carbone (CO) dans l'air expiré. Etude randomisée effectuée auprès de 578 fumeurs consultant en médecine générale.

UNLABELLED: Nicotine addiction (NA) is a serious public health problem and helping patients to stop consumption is a major concern for general practitioners (GP). The positive effects of "brief advice" are well known. The aim of our paper is to evaluate the effectiveness of adding exhaled carbon monoxide (CO) measurement using a CO analyser to a normal smoking cessation practice in a GP's office. METHODS: This was a descriptive study, using a questionnaire, among randomised smoking patients; one group receiving brief advice and the other brief advice plus exhaled CO analysis in their GP's office. RESULTS: Five hundred and seventy-eight questionnaires were analysed: 60% of smoking patients wished to stop smoking and 72% within the next 6 months, without significant difference between the two groups. In the group "minimal advice plus CO analyser" (282), 60% of the smokers reported that they had been influenced by the results of the level of CO in the exhaled air and were more motivated to quit because of this. CONCLUSION: Measuring the level of exhaled CO in smokers helps to inform them of the dangers of their addiction and helps to motivate them to quit.