Annexin A3 as a Marker Protein for Microglia in the Central Nervous System of Rats.

The parenchymal microglia possess different morphological characteristics in cerebral physiological and pathological conditions; thus, visualizing these cells is useful as a means of further investigating parenchymal microglial function. Annexin A3 (ANXA3) is expressed in microglia, but it is unknown whether it can be used as a marker protein for microglia and its physiological function. Here, we compared the distribution and morphology of parenchymal microglia labeled by ANXA3, cluster of differentiation 11b (CD11b), and ionized calcium-binding adaptor molecule 1 (Iba1) and measured the expression of ANXA3 in nonparenchymal macrophages (meningeal and perivascular macrophages). We also investigated the spatiotemporal expression of ANXA3, CD11b, and Iba1 in vivo and in vitro and the cellular function of ANXA3 in microglia. We demonstrated that ANXA3-positive cells were abundant and evenly distributed throughout the whole brain tissue and spinal cord of adult rats. The morphology and distribution of ANXA3-labeled microglia were quite similar to those labeled by the microglial-specific markers CD11b and Iba1 in the central nervous system (CNS). ANXA3 was expressed in the cytoplasm of microglia, and its expression was significantly increased in activated microglia. ANXA3 was almost undetectable in the nonparenchymal macrophages. Meanwhile, the protein and mRNA expression levels of ANXA3 in different regions of the CNS were different from those of CD11b and Iba1. Moreover, knockdown of ANXA3 inhibited the proliferation and migration of microglia, while overexpression of ANXA3 enhanced these activities. This study confirms that ANXA3 may be a novel marker for parenchymal microglia in the CNS of adult rats and enriches our understanding of ANXA3 from expression patterns to physiological function.

PR3 levels are impaired in plasma and PBMCs from Arabs with cardiovascular diseases.

Cardiovascular disease (CVD) risks persist in patients despite treatment. CVD susceptibility also varies with sex and ethnicity and is not entirely explained by conventional CVD risk factors. The aim of the present study was to identify novel CVD candidate markers in circulating Peripheral blood mononuclear cells (PBMCs) and plasma from Arab obese subjects with and without CVD using proteomic approaches. Human adults with confirmed CVD (n = 208) and matched non-CVD controls (n = 152) living in Kuwait were examined in the present cross-sectional study. Anthropometric and classical biochemical parameters were determined. We employed a shotgun proteomic profiling approach on PBMCs isolated from a subset of the groups (n = 4, each), and differentially expressed proteins selected between the two groups were validated at the mRNA level using RT-PCR (n = 6, each). Plasma levels of selected proteins from the proteomics profiling: Proteinase-3 (PR3), Annexin-A3 (ANX3), Defensin (DEFA1), and Matrix Metalloproteinase-9 (MMP9), were measured in the entire cohort using human enzyme-linked immunosorbent assay kits and were subsequently correlated with various clinical parameters. Out of the 1407 we identified and quantified from the proteomics profiling, 47 proteins were dysregulated with at least twofold change between the two subject groups. Among the differentially expressed proteins, 11 were confirmed at the mRNA levels. CVD influenced the levels of the shortlisted proteins (MMP9, PR3, ANX3, and DEFA1) in the PBMCs and plasma differentially. Despite the decreased levels of both protein and mRNA in PBMCs, PR3 circulating levels increased significantly in patients with CVD and were influenced by neither diabetes nor statin treatment. No significant changes were; however, observed in the DEFA1, MMP9, and ANX3 levels in plasma. Multivariate logistic regression analysis revealed that only PR3 was independently associated with CVD. Our results suggest that the dysregulation of PR3 levels in plasma and PBMCs reflects underlying residual CVD risks even in the treated population. More prospective and larger studies are required to establish the role of PR3 in CVD progression.

Overexpression of ANXA3 is an independent prognostic indicator in gastric cancer and its depletion suppresses cell proliferation and tumor growth.

BACKGROUND: Gastric cancer (GC) is one of the most common malignancies worldwide. Tumour metastasis is one of the leading causes of death in GC patients. This study aims to investigate the significance of ANXA3 expression and the mechanism by which ANXA3 is involved in the epithelial-mensenchymal transition (EMT) of gastric cancer cells. RESULTS: Our results confirmed that ANXA3 was high expression at the mRNA and protein level in GC cancer tissues and the majority of GC cell lines. In clinicopathological analysis, we found that increased expression of ANXA3 in tumors was closely associated with a poor prognosis. Xogenous ANXA3 transduction promoted proliferation, clone formation, migration, and invasion. Small interfering RNA silencing of ANXA3 inhibited these processes. Silence of ANXA3 inhibited tumorigenicity in vivo. Additionally, ANXA3 expression is associated with the epithelial-mesenchymal transition. METHODS: Firstly, we investigated the ANXA3 expression on mRNA and protein level with RT-PCR and Western blot. Secondly, 183 GC patients tissues were used the to evaluate the clinicopathological characteristics and prognosis through immunohistochemistry. Furthermore, The functions of ANXA3 were analyzed in the cell proliferation, Colony Formation, migration, invasion and apoptosis of GC cell lines. CONCLUSIONS: Our research suggests that ANXA3 plays important roles in gastric cancer carcinogenesis and metastasis, and provides a valuable prognostic marker and potential target for treatment of gastric cancer patients.

Common histological patterns in glomerular epithelial cells in secondary focal segmental glomerulosclerosis.

Parietal epithelial cells (PECs) are involved in the development of sclerotic lesions in primary focal and segmental glomerulosclerosis (FSGS). Here, the role of PECs was explored in the more common secondary FSGS lesions in 68 patient biopsies, diagnosed with 11 different frequently or rarely encountered glomerular pathologies and additional secondary FSGS lesions. For each biopsy, one section was quadruple stained for PECs (ANXA3), podocytes (synaptopodin), PEC matrix (LKIV69), and Hoechst (nuclei), and a second was quadruple stained for activated PECs (CD44 and cytokeratin-19), PEC matrix, and nuclei. In all lesions, cellular adhesions (synechiae) between Bowman's capsule and the tuft were formed by cells expressing podocyte and/or PEC markers. Cells expressing PEC markers were detected in all FSGS lesions independent of the underlying glomerular disease and often stained positive for markers of activation. Small FSGS lesions, which were hardly identified on PAS sections previously, were detectable by immunofluorescent staining using PEC markers, potentially improving the diagnostic sensitivity to identify these lesions. Thus, similar patterns of cells expressing podocyte and/or PEC markers were found in the formation of secondary FSGS lesions independent of the underlying glomerular disease. Hence, our findings support the hypothesis that FSGS lesions follow a final cellular pathway to nephron loss that includes involvement of cells expressing PEC markers.

Impact of Annexin A3 expression in gastric cancer cells.

Annexin A3 participates in various biological processes, including tumorigenesis, drug resistance, and metastasis. The aim of this study was to investigate the expression of Annexin A3 in gastric cancer and its relationship with cell differentiation, migration, and invasion of gastric cancer cells. Annexin A3 expression in gastric cancer tissues was detected by quantitative real-time PCR and Western blotting. The proliferation of gastric cancer cells was measured by the MTT assay. Cell migration and invasion were determined via wound healing and transwell assays, respectively. Knock down of endogenous Annexin A3 in gastric cancer BGC823 cells was performed using siRNA technology. The expression of Annexin A3 was significantly upregulated in gastric cancer tissues, and negatively correlated with the differentiation degree. Silencing of endogenous Annexin A3 suppressed the proliferation, migration, and invasion of BGC823 cells. Additionally, the expression of p21, p27, TIMP-1, and TIMP-2 was upregulated, and the expression of PCNA, cyclin D1, MMP-1, and MMP-2 decreased in cells treated with Annexin A3-siRNA. Annexin A3 was upregulated in gastric cancer cells. Deletion of endogenous Annexin A3 significantly inhibited gastric cancer cell proliferation, migration, and invasion.

[Proteomic analysis of human ovarian cancer cell lines and their platinum-resistant clones].

OBJECTIVE: To perform comparative proteomic analysis of human ovarian cancer cell lines for detecting platinum-resistance associated proteins. METHODS: The total proteins of two sensitive (SKOV3 and A2780) and four resistant (SKOV3/CDDP, SKOV3/CBP, A2780/CDDP and A2780/CBP) human ovarian cancer cell lines were separated by two-dimensional gel electrophoresis (2-DE). The differentially expressed proteins were analyzed using image analysis software, stained with Coomassie Brilliant Blue, then identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) and database searching. The mRNA and protein levels of the differentially expressed protein which was most significant in all of the four resistant cell lines were validated by RT-PCR and western blotting, respectively. RESULTS: Five proteins were found to be significant in four cell lines. Annexin A3 and destrin were up-regulated and nicotinamide-adenine dinucleotide phosphate (NADP)-dependent isocitrate dehydrogenase 1 was down-regulated in all the four resistant samples. Glutathione transferase omega 1 had an increased expression in the other three resistant cell lines except for SKOV3/CBP in which its expression was not changed. However, cofilin 1 represented a different trend. In the two resistant sublines of SKOV3, cofilin 1 had a down-regulation, but it had an up-regulation in the cell lines induced from SKOV3. The expression of annexin A3 was up-regulated by 3 - 20 fold and the results of RT-PCR and western blotting showed complete consistency with that by 2-DE. CONCLUSIONS: Proteomic techniques are useful to the identification of the resistance-associated proteins in ovarian cancer platinum-resistant cell lines and five candidates have been found. The five differential proteins might become hopeful candidate biomarkers for resistance.

Application of laser capture microdissection combined with two-dimensional electrophoresis for the discovery of differentially regulated proteins in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is the most lethal of all the common malignancies and markers for early detection or targets for treatment of this disease are urgently required. The disease is characterised by a strong stromal response, with cancer cells usually representing a relatively small proportion of the cells in the tumor mass. We therefore performed laser capture microdissection (LCM) to enrich for both normal and malignant pancreatic ductal epithelial cells. Proteins extracted from these cells were then separated by two-dimensional gel electrophoresis (2-DE). The limited amounts of protein in the LCM procured samples necessitated the detection of 2-DE resolved proteins by silver staining. Consequently, loading equivalent amounts of protein onto gels was essential. However, we found that conventional means of measuring total protein in the samples were not sufficiently accurate. We therefore adopted a strategy in which the samples were first separated by one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis, stained with silver stain and subjected to densitometry. Evaluation of the staining intensity was then used to normalise the samples. We found that the protein profiles from undissected normal pancreas and LCM-acquired non-malignant ductal epithelial cells from the same tissue block were different, underpinning the value of LCM in our analysis. The comparisons of protein profiles from nonmalignant and malignant ductal epithelial cells revealed nine protein spots that were consistently differentially regulated. Five of these proteins showed increased expression in tumor cells while four showed diminished expression in these cells. One of the proteins displaying enhanced expression in tumor cells was identified as the calcium-binding protein, S100A6. To determine the incidence of S100A6 overexpression in pancreatic cancer, we carried out immunohistochemical analysis on sections from a pancreas cancer tissue array containing 174 duplicate normal and malignant pancreatic tissue samples, from 46 pancreas cancer patients. Normal pancreatic ductal epithelia were either devoid of detectable S100A6 or showed weak expression only. Moderately or poorly differentiated tumors, by contrast, showed a higher incidence and a higher level of S100A6 expression. These observations indicate that the combination of LCM with 2-DE provides an effective strategy to discover proteins that are differentially expressed in PDAC.

Specific expression of annexin III in rat-small-hepatocytes.

Small hepatocytes are cells that express characteristic phenotypes such as a high growth potential and differentiation capacity. In order to identify rat-small-hepatocyte specific proteins, we separated the cellular proteins of isolated small and parenchymal hepatocytes by 2D polyacrylamide gel electrophoresis. Comparison of their profiles revealed a protein with a molecular mass of 37 kDa in the small hepatocytes that was not present in the parenchymal hepatocytes. Proteolytic peptide mass fingerprinting was used to identify the protein and it was found to be annexin III. The validity of the identification was confirmed by Western blot analysis with anti-annexin III antibody.

Differential expression of annexins I-VI in the rat dorsal root ganglia and spinal cord.

The annexins are a family of Ca(2+)-dependent phospholipid-binding proteins. In the present study, the spatial expression patterns of annexins I-VI were evaluated in the rat dorsal root ganglia (DRG) and spinal cord (SC) by using indirect immunofluorescence. Annexin I is expressed in small sensory neurons of the DRG, by most neurons of the SC, and by ependymal cells lining the central canal. Annexin II is expressed by most sensory neurons of the DRG but is primarily expressed in the SC by glial cells. Annexin III is expressed by most sensory neurons, regardless of size, by endothelial cells lining the blood vessels, and by the perineurium. In the SC, annexin III is primarily expressed by astrocytes. In the DRG and the SC, annexin IV is primarily expressed by glial cells and at lower levels by neurons. In the DRG, annexin V is expressed in relatively high concentrations in small sensory neurons in contrast to the SC, where it is expressed mainly by ependymal cells and by small-diameter axons located in the superficial laminae of the dorsal horn areas. Annexin VI is differentially expressed by sensory neurons of the DRG, being more concentrated in small neurons. In the SC, annexin VI has the most striking distribution. It is concentrated subjacent to the plasma membrane of motor neurons and their processes. The differential localization pattern of annexins in cells of the SC and DRG could reflect their individual biological roles in Ca(2+)-signal transduction within the central nervous system.

Distribution of annexins I, II, and IV in bovine mammary gland.

Annexins belong to a family of proteins that are characterized by their ability to bind phospholipids in a Ca(2+)-dependent manner that is thought to be involved in a variety of biological processes. The present study determined the localization of annexins in subcellular fractions, nuclei in particular, of cow mammary gland by immunoblot analysis using monoclonal antibodies to annexins I, II, IV, and VI. The analysis revealed that annexins I, II, and IV were present in cytosol, but VI was not. Annexins I and IV were found in the nuclear fraction, but annexin II was only faintly present. Annexin VI was also undetectable in this fraction. Cytosolic annexin I had a molecular mass of 36 kDa. The 36-kDa annexin I was also found in the nuclear fraction. A 38-kDa annexin I was additionally detected in nuclei. The cytosolic and nuclear 36-kDa annexin I and the nuclear 38-kDa annexin I showed different isoelectric points, as revealed by two-dimensional PAGE. Annexin IV from cytosolic and nuclear fractions had similar molecular masses and isoelectric points.