Tyrosine phosphorylation of insulin receptor substrates during ischemia/reperfusion-induced apoptosis in rat liver

Src homolog and collagen homolog1 isoforms in acute and chronic liver injuries

Src homolog and collagen homolog (SHC) proteins are adaptor proteins bound to cell surface receptors that play an important role in signal transduction and related diseases. As an important member of the SHC protein family, SHC1 regulates cell proliferation and apoptosis, reactive oxygen species (ROS) production, and oxidative stress. Three isomeric proteins namely, p46shc, p52shc, and p66shc, are produced from the same SHC1 gene locus. All the three proteins are found in the liver, and are widely expressed in various hepatic cells. SHC1 has been proven to be associated with acute and chronic liver injuries of different etiologies, and plays important roles in liver fibrosis and hepatocellular carcinoma (HCC). Therefore, this review summarizes recent studies that discuss and explore the role of SHC1 in the occurrence and progression of liver diseases. We also provide a theoretical basis for future studies.

Fluorochrome-labeled inhibitors of caspases: convenient in vitro and in vivo markers of apoptotic cells for cytometric analysis

Activation of caspases is a hallmark of apoptosis. Several methods, therefore, were developed to identify and count the frequency of apoptotic cells based on the detection of caspases activation. The method described in this chapter is based on the use of fluorochrome-labeled inhibitors of caspases (FLICA) applicable to fluorescence microscopy, and flow- and image-cytometry. Cell-permeant FLICA reagents tagged with carboxyfluorescein or sulforhodamine when applied to live cells in vitro or in vivo, exclusively label cells that are undergoing apoptosis. The FLICA labeling methodology is simple, rapid, robust, and can be combined with other markers of cell death for multiplexed analysis. Examples are presented on FLICA use in combination with a vital stain (propidium iodide), detection of the loss of mitochondrial electrochemical potential, and exposure of phosphatidylserine on the outer surface of plasma cell membrane using Annexin V fluorochrome conjugates. Following cell fixation and stoichiometric staining of cellular DNA, FLICA binding can be correlated with DNA ploidy, cell cycle phase, DNA fragmentation, and other apoptotic events whose detection requires cell permeabilization. The "time window" for the detection of apoptosis with FLICA is wider compared to that with the Annexin V binding, making FLICA a preferable marker for the detection of early phase apoptosis and more accurate for quantification of apoptotic cells.

In vivo morphine treatment synergistically increases LPS-induced caspase activity in immune organs

Caspases are a family of proteins important for the elimination of infected cells through the induction of apoptosis as well as the initiation of inflammatory cytokines including IL-1β and IL-18. Morphine exposure to animals and/or cells has been associated with the induction of apoptosis. The most common practices of apoptosis detection have involved removing tissues from animal or humans and the analysis of apoptosis on cells or tissues. These methods can potentially induce spontaneous apoptosis that is unrelated to the actual treatment. The objective of this study was to develop an in vivo detection method for assessing caspase activity induced both by morphine directly and by morphine combined with lipopolysaccharide (LPS)-immune activation. Mice were administered saline, morphine, LPS, or a combination of morphine and LPS. Prior to sacrifice, mice were injected with a polycaspase-specific apoptosis detection probe to detect internal caspase activity in vivo. Results revealed that morphine alone did not directly induce caspase activity. However, morphine significantly enhanced the LPS-induced caspase activity in spleen, thymus, and bone marrow-derived immune cells. The use of a poly-caspase detection probe methodology to label caspase activity in vivo provides a powerful quantitative tool for the in vivo analysis of caspase activity.