Proteomic and ultrastructural analysis of Clara cell and type II alveolar epithelial cell-type lung cancer cells.

BACKGROUND: Currently, the identification of Clara cell and type II alveolar epithelial cell-type cancer cells requires electron microscopy, which is a time-consuming and expensive process involving a complicated tissue sampling procedure. The aim of this study was to identify unique biomarkers for Clara cell and type II alveolar epithelial cell-type lung cancer cells, respectively, with proteomic profiling. METHODS: Six human lung adenocarcinoma cell lines (A549, NCI-H358, NCI-H1650, HCC827, NCI-H1395, and NCI-H1975) were investigated for their ultrastructural characteristics. The differentially expressed proteins (DEPs) were screened between NCI-H358 cells (Clara cell type) and A549 cells (type II alveolar epithelial cell type) using two-dimensional difference gel electrophoresis (2D-DIGE) and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS/MS), and then they were validated by western blot. The protein expression levels of endoplasmic reticulum oxidoreductin 1-α (ERO1L), Clara cell 10-kD protein (CC10), and surfactant protein C (SP-C) were also determined in the six cell lines assayed. RESULTS: NCI-H358 cells featured Clara cell differentiation; A549, NCI-H1975, and HCC827 cells had characteristics of type II alveolar epithelial cells; and NCI-H1395 and NCI-H1650 cells had no differentiation characteristics of any lung adenocarcinoma cell type. Five DEPs including ubiquitin carboxyl-terminal hydrolase isozyme L1 (UCHL1), cytokeratin 19 (CK19), cytokeratin 8 (CK8), ERO1L, and peroxiredoxin 2 (PRDX2) between NCI-H358 and A549 cells were identified for further validation; however, none of them showed suitability as an effective biomarker. Similarly, CC10 and SP-C were not appropriate biomarkers. CONCLUSIONS: Cytological subtypes of NCI-H1975 and HCC827 cells were identified, but no promising biomarker was discovered in the present study.

α-lipoic acid protects dopaminergic neurons against MPP+-induced apoptosis by attenuating reactive oxygen species formation.

Reactive oxygen species (ROS) elicited by oxidative stress are widely recognized as a major initiator in the dege-neration of dopaminergic neurons distinctive of Parkinson's disease (PD). The interaction of ROS with mitochondria triggers sequential events in the mitochondrial cell death pathway, which is thought to be responsible for ROS-mediated neurodegeneration in PD. α-lipoic acid (LA) is a pleiotropic compound with potential pharmacotherapeutic value against a range of pathophysiological insults. Its protective actions against oxidative damage by scavenging ROS and reducing production of free radicals have been reported in various in vitro and in vivo systems. This study analyzed the ability of LA to protect PC12 neuronal cells from toxicity of 1-methyl-4-phenylpyridinium (MPP+), the neurotoxic metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) which is known to kill dopaminergic neurons selectively and to cause severe parkinsonism-like symptoms in humans and primate animals. Our results demonstrate that the apoptosis of PC12 cells elicited by MPP+ could be significantly prevented by pretreatment with LA for 1 h. In addition, LA inhibits intercellular ROS levels and the mitochondrial transmembrane permeability, the key players in the pathogenesis of PD, thereby protecting dopaminergic neuronal cells against oxidative damage.

Contribution of endothelial progenitor cells to neovascularization (Review).

Endothelial progenitor cells (EPCs) are a cell population mobilized from bone marrow into the peripheral circulation and recruited into sites of vessel injury to participate in blood vessel formation in both physiological and pathological conditions. Due to the lack of unique surface markers and different isolation methods, EPCs represent heterogeneous cell populations including cells of myeloid or endothelial origin. Evidence suggests that EPCs play a critical role in postnatal blood vessel formation and vascular homeostasis and provide a promising therapy for vascular disease. However, the mechanisms by which EPCs participate in new vessel formation are still incompletely understood. We review the process of EPCs in neovascularization including EPC mobilization, migration, adhesion and effect on new vessel formation, in an attempt to better understand the underlying mechanisms and to provide potential effective management for the treatment of patients with vascular disease.

Proteomic analysis of oxidative modification in endothelial colony-forming cells treated by hydrogen peroxide.

Endothelial progenitor cells (EPCs) which circulate in the peripheral blood and reside in blood vessels are proven to promote the repair of damaged endothelium and improve the function of endothelial cells after vascular injury. Recently, EPCs have been extensively studied as risk biomarkers and a potential therapeutic tool for cardiovascular disease. It is known that oxidative stress is one of the most important pathogenetic factors impairing endothelial function. During the repair process after endothelial injury, EPCs are exposed to oxidative stress. In this study, we treated endothelial colony-forming cells (ECFCs) with hydrogen peroxide (H2O2) as an oxidative stress model and observed the changes in cytology and morphology of ECFCs. In addition, we investigated the alterations in oxidative levels of proteins associated with H2O2-induced morphological and cytological changes in ECFCs by proteomic analysis of oxidative modification. The results showed that H2O2 treatment led to a decreased proliferation, increased apoptosis and impaired tube-forming ability of ECFCs in a dose-dependent manner. Five proteins with upregulated oxidative levels were identified successfully. The upregulated oxidative levels of these five proteins may be responsible for the dysfunction of ECFCs under oxidative stress. Our results may provide some novel insights into the molecular mechanisms of oxidative stress action on ECFCs.

SH-SY5Y human neuroblastoma cell line: in vitro cell model of dopaminergic neurons in Parkinson's disease.

OBJECTIVE: To evaluate the human neuroblastoma SH-SY5Y cell line as an in vitro model of dopaminergic (DAergic) neurons for Parkinson's disease (PD) research and to determine the effect of differentiation on this cell model. DATA SOURCES: The data of this review were selected from the original reports and reviews related to SH-SY5Y cells published in Chinese and foreign journals (Pubmed 1973 to 2009). STUDY SELECTION: After searching the literature, 60 articles were selected to address this review. RESULTS: The SH-SY5Y cell line has become a popular cell model for PD research because this cell line posses many characteristics of DAergic neurons. For example, these cells express tyrosine hydroxylase and dopamine-beta-hydroxylase, as well as the dopamine transporter. Moreover, this cell line can be differentiated into a functionally mature neuronal phenotype in the presence of various agents. Upon differentiation, SH-SY5Y cells stop proliferating and a constant cell number is subsequently maintained. However, different differentiating agents induce different neuronal phenotypes and biochemical changes. For example, retinoic acid induces differentiation toward a cholinergic neuronal phenotype and increases the susceptibility of SH-SY5Y cells to neurotoxins and neuroprotective agents, whereas treatment with retinoic acid followed by phorbol ester 12-O-tetradecanoylphorbol-13-acetate results in a DAergic neuronal phenotype and decreases the susceptibility of cells to neurotoxins and neuroprotective agents. Some differentiating agents also alter kinetics of 1-methyl-4-phenyl-pyridinium (MPP(+)) uptake, making SH-SY5Y cells more similar to primary mesencephalic neurons. CONCLUSIONS: Differentiated and undifferentiated SH-SY5Y cells have been widely used as a cell model of DAergic neurons for PD research. Some differentiating agents afford SH-SY5Y cells with more potential for studying neurotoxicity and neuroprotection and are thus more relevant to experimental PD research.

Proteomic analysis of kidney in fluoride-treated rat.

The recent development of proteomic techniques has enabled investigators to directly examine the population of proteins present in biological systems. We first report here the proteomic changes of renal protein induced by fluoride. To investigate molecular mechanisms of renal injury induced by fluoride, proteins were isolated from rat kidney and profiled by two-dimensional gel electrophoresis (2DE). With the analysis of Image-Master 2D Elite software, 141 up-regulated and eight down-regulated protein spots in 2DE gels of fluoride-treated group were gained by comparison to the control group, 13 of which were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). The identified proteins are mainly related with cell proliferation, metabolism and oxidative stress, and provide a valuable clue to explore the mechanism of renal fluorosis. This study also shows that the proteomic techniques were powerful in fluoride toxical field.