Mechanistic issues of the interaction of the hairpin-forming domain of tBid with mitochondrial cardiolipin.

Background: The pro-apoptotic effector Bid induces mitochondrial apoptosis in synergy with Bax and Bak. In response to death receptors activation, Bid is cleaved by caspase-8 into its active form, tBid (truncated Bid), which then translocates to the mitochondria to trigger cytochrome c release and subsequent apoptosis. Accumulating evidence now indicate that the binding of tBid initiates an ordered sequences of events that prime mitochondria from the action of Bax and Bak: (1) tBid interacts with mitochondria via a specific binding to cardiolipin (CL) and immediately disturbs mitochondrial structure and function idependently of its BH3 domain; (2) Then, tBid activates through its BH3 domain Bax and/or Bak and induces their subsequent oligomerization in mitochondrial membranes.

Interaction of the alpha-helical H6 peptide from the pro-apoptotic protein tBid with cardiolipin.

BH3 interacting domain death agonist (Bid), a pro-apoptotic member of the Bcl-2 family of proteins, is activated through cleavage by caspase-8. The active C-terminal fragment of Bid (tBid) translocates to the mitochondria where it interacts with cardiolipins at contact sites and induces the release of cytochrome c by a mechanism that is not yet fully understood. It has been shown that the alpha-helices alphaH6 and alphaH7 (which create the hairpin-forming domain of tBid) mediate the insertion of Bid into mitochondrial membranes and are essential for the cytochrome c-releasing activity.

Effects of toluene and benzene air mixtures on human lung cells (A549).

Human epithelial lung cells (A549) were exposed to toluene and benzene in the air as individual compounds and mixtures at concentrations of about 0.25ppmv in a specifically adapted fumigation device. Possible early toxicological effects at cellular level have been determined by lactate dehydrogenase (LDH), glutathione redox status (GSH) and comet assay.

An optimized method for in vitro exposure of human derived lung cells to volatile chemicals.

Volatile organic compounds (VOCs) such as benzene and toluene, and low molecular weight carbonyls like formaldehyde belong to the main air pollutants found in indoor environments. They are suspected to induce acute and chronic adverse health effects like asthma, allergic and cardiovascular diseases, and strongly affect well-being. Our aim was to further develop and optimize an in vitro method to study the exposure of epithelial tumour lung cells (A549) by using a commercial exposure chamber (CULTEX) to assess the biological effects of VOCs and carbonyl compounds at low concentration levels.

Establishment and characterization of new mammary adenocarcinoma cell lines derived from double transgenic mice expressing GFP and neu oncogene.

A new murine cell line, named GFPneu, was established from a mammary adenocarcinoma arising in double transgenic MMTVneu x CMV-GFP mice. Breast tumours develop in 100% of females after 2 months latency, as a result of the over-expression of the activated rat neu oncogene in the mammary glands. All tissues, and in particular the breast tumours, express the GFP protein.