Retrospective biodosimetry using translocation frequency in a stable cell of occupationally exposed to ionizing radiation.

Two cases of hematological malignancies were reported in an industrial radiography company over a year, which were reasonably suspected of being consequences of prolonged exposure to ionizing radiation because of the higher incidence than expected in the general population. We analyzed chromosomal aberrations in the peripheral blood lymphocytes from the other workers who had been working under similar circumstances as the patients in the company. Among the subjects tested, 10 workers who belonged to the highest band were followed up periodically for 1.5 years since the first analysis. The aim of this study was to clarify pertinence of translocation analysis to an industrial set-up where chronic exposure was commonly expected. To be a useful tool for a retrospective biodosimetry, the aberrations need to be persistent for a decade or longer. Therefore we calculated the decline rates and half-lives of frequency for both a reciprocal translocation and a dicentric chromosome and compared them. In this study, while the frequency of reciprocal translocations was maintained at the initial level, dicentric chromosomes were decreased to 46.9% (31.0-76.5) of the initial frequency over the follow-up period. Our results support the long-term stability of reciprocal translocation through the cell cycle and validate the usefulness of translocation analysis as a retrospective biodosimetry for cases of occupational exposure.

Analysis of vanin-1 upregulation and lipid accumulation in hepatocytes in response to a high-fat diet and free fatty acids.

High-fat diet is one of the causes of nonalcoholic fatty liver disease. We have previously demonstrated that high-fat diet induces upregulation of adipose differentiation-related protein mRNA expression accompanied by lipid droplet formation in mouse liver. Vanin-1 is a ubiquitous epithelial ectoenzyme that has pantetheinase activity and produces cysteamine, a potent endogenous antioxidant. In the present study, we analyzed the expression of hepatic vanin-1 mRNA following the administration of a high-fat diet in mice as well as free fatty acids in hepatocyte cultures and speculated its possible mechanism. Vanin-1 mRNA levels in the livers of mice were upregulated within a day of the high-fat diet, even before the expression of adipose differentiation-related protein mRNA and lipid accumulation. An in vitro analysis using HuH-7 cells revealed a significant upregulation of vanin-1 mRNA by as low as 0.01 mM oleic acid; however, lipid accumulation in hepatocytes was not affected at this concentration. Furthermore, vanin-1 mRNA was differentially upregulated by various free fatty acids irrespective of the grade of lipid accumulation. These findings indicate that the upregulation of vanin-1 precedes lipid accumulation and is differentially mediated by various types of free fatty acids in the model, presenting vanin-1 as a novel player in the pathogenesis of nonalcoholic fatty liver disease.

Neuroprotective effects of black soybean anthocyanins via inactivation of ASK1-JNK/p38 pathways and mobilization of cellular sialic acids.

AIMS: To investigate neuroprotective effects of three major anthocyanins (cyanidin-3-O-glucoside, delphinidin-3-O-glucoside, and petunidin-3-O-glucoside) isolated from the black soybean (Glycine max L.) cv. Cheongja 3 seed coat against H(2)O(2)-induced cell death of human brain neuroblastoma SK-N-SH cells. MAIN METHODS: Cell viability, reactive oxygen species (ROS) generation, production and expression of heme oxygenase (HO)-1 and inactivation of mitogen-activated protein (MAP) kinase cascades were determined by MTT assay, 2,7-dichlorofluorescein diacetate (DCF-DA) assay, reverse transcriptase polymerase chain reaction (RT-PCR), and western blotting, respectively. KEY FINDINGS: Pretreatment with anthocyanins reduced the cytotoxicity of H(2)O(2) on SK-N-SH cells, dose-dependently reduced the intracellular ROS level and inactivated apoptosis signal-regulating kinase (ASK1, Thr845), p38, and c-Jun N-terminal kinase (JNK) proteins. The HO-1 and Neu1 mRNA levels were increased by H(2)O(2) (25 µM) and further elevated by the pretreatment with anthocyanins. Sialic acids added to the culture plates not only attenuated the cytotoxicity of H(2)O(2) (25 µM) but also reduced intracellular ROS level. These results suggest that Cheongja 3 black soybean seed coat anthocyanins have brain neuroprotective effects against oxidative stress (H(2)O(2)) by inhibiting the activation of ASK1-JNK/p38 pathways, scavenging ROS, stimulating the expression of HO-1 and, more interestingly, recruiting cellular free sialic acids through up-regulation of Neu1 sialidase gene expression. SIGNIFICANCE: This is the first report indicating potent health benefits of black soybean seed coat anthocyanins in neuroprotection by triggering mobilization of cellular free sialic acid and utilizing it as an additional biological antioxidant in brain neural cells.

Comparison of human blood concentrations of collectin kidney 1 and mannan-binding lectin.

Mannan-binding lectin (MBL) was first discovered as a collectin in animal blood, and was shown to have such unique characteristics as a collage-like domain and a carbohydrate recognition domain. We recently identified human collectin kidney 1 (CL-K1, COLEC11) from a human kidney cDNA library. To quantitate the CL-K1 concentration in blood, we developed several polyclonal and monoclonal antibodies using recombinant human CL-K1 in CHO cells and the CL-K1 fragment in Escherichia coli. Using these antibodies, we established a sandwich enzyme-linked immunosorbent assay (ELISA) system. The concentration of CL-K1 in human plasma was 0.34 ± 0.13 µg/ml and that in MBL was 1.72 ± 1.51 µg/ml. Concentrations of MBL are often low due to its single nucleotide polymorphisms (SNPs) which seem to be related to an opsonic defect. However, no low concentrations of CL-K1 were observed on testing over two hundred blood samples. We also found that the blood concentration of CL-K1 was not dependent on gender or age and did not correlate completely with that of MBL. The ELISA system developed in this study will be useful for elucidating the physiological and pathophysiological role of CL-K1 in humans.

Molecular cloning and functional analysis of scavenger receptor zebrafish CL-P1.

BACKGROUND: Scavenger receptors are generally expressed in macrophages and vascular endothelial cells and some scavenger receptors are thought to contribute to the development of atherosclerosis. METHODS: We cloned the cDNA of a zebrafish CL-P1 (collectin placenta 1) and performed a knockdown study using its antisense morpholino oligonucleotides (MO). RESULTS: Zebrafish CL-P1 (zCL-P1) is 51% identical to human CL-P1 in its amino acid sequence. Microbes and OxLDL bound to zCL-P1 cDNA transfected cells. zCL-P1 mRNA expression gradually increased after 6hours post-fertilization (hpf), reached its highest level at 24hpf, and then decreased, which is similar to the gene expression pattern of Tie-2. The knockdown of zCL-P1 led to an increase in the number of zebrafish embryos with severe morphological abnormalities such as short body lengths and defects in the dorsal aorta at 48hpf. Simultaneous injection of both MO and synthetic zCL-P1 or zVEGF mRNA rescued the abnormal phenotype. CONCLUSIONS: In vivo knockdown study shows that zCL-P1 is implicated in vasculogenesis and those of our in vitro study support its role as a scavenger receptor. GENERAL SIGNIFICANCE: These results suggest that zCL-P1 might be essential for vasculogenesis during the early embryonic phase in bone fish.

The induction of human CL-P1 expression in hypoxia/reoxygenation culture condition and rat CL-P1 after ischemic/reperfusion treatment.

BACKGROUND: Oxidative stress-induced endothelial dysfunction and oxidized low-density lipoprotein (LDL) might play a key role in the pathogenesis of atherosclerosis. We recently identified a vascular endothelial scavenger receptor, collectin placenta 1 (CL-P1), which acts as a receptor for oxidized LDL as well as for microbes. METHODS: We demonstrate how hypoxic and oxidative stress induced CL-P1 expression and compared their effects with the expression of lectin-like oxidized low-density lipoprotein receptor 1 (LOX-1), an endothelial scavenger receptor expressed by oxidative stress. RESULTS: Hypoxia/reoxygenation induced CL-P1 mRNA and protein expression in human umbilical vein endothelial cells (HUVECs). The expression of LOX-1 mRNA in these cells peaked slightly at 24 h, while the expression of CL-P1 had an onset at 72 h and was sustained for 120 h after reoxygenation. Furthermore, the exposure of rat carotid artery endothelium to ischemia/reperfusion increased the maximal CL-P1 mRNA expression at 72 h and expression of its protein peaked at 7 days after this treatment. We demonstrate that CL-P1 up-regulation is induced in vitro and in vivo by oxidative stress. GENERAL SIGNIFICANCE: The inducible expression of CL-P1 by oxidative stress might play a crucial role in endothelial dysfunction or chronic activation leading to the pathogenesis of atherosclerosis.

Immunolocalization of a novel collectin CL-K1 in murine tissues.

We have recently identified a novel collectin, CL-K1, that may play a role in innate immunity as a member of the collectin family. In this study using mice, we investigated the tissue distribution of CL-K1 for better understanding of its pathophysiological relevance. Real-time PCR analyses demonstrated that CL-K1 mRNA was expressed in all tissues tested. Immunohistochemical analyses demonstrated that CL-K1 was expressed in proximal tubules of kidney, in mucosa of the gastrointestinal tract, and in bronchial glands of bronchioles similar to the localization of SP-A and SP-D in these pulmonary structures. Immunohistochemistry also showed that CL-K1 was highly expressed in hepatocytes around the central veins in liver, which suggests that murine CL-K1 may be mainly produced in the liver and secreted into the blood stream as is human CL-K1. CL-K1 was especially detected in vascular smooth muscle in several types of tissues. In addition, it was also expressed in intestinal Paneth cells, in mesangial cells of kidney, in pancreatic islet D cells, and in neurons of the brain. It is of interest that this profile of CL-K1 expression is unique among the collectins. Together these histological findings may be useful for understanding the biological function of this novel collectin.

Identification and characterization of a novel human collectin CL-K1.

Collectins are a family of C-type lectins with two characteristic structures, collagen like domains and carbohydrate recognition domains. They recognize carbohydrate antigens on microorganisms and act as host-defense. Here we report the cloning and characterization of a novel collectin CL-K1. RT-PCR analyses showed CL-K1 mRNA is present in all organs. The deduced amino acid sequence and the data from immunostaining of CL-K1 cDNA expressing CHO cells revealed that CL-K1 is expressed as a secreted protein. CL-K1 is found in blood by immunoblotting and partial amino acid analyses. CL-K1 showed Ca(2+)-dependent sugar binding activity of fucose and weakly mannose but not N-acetyl-galactosamine, N-acetyl-glucosamine, or maltose, though mannose-binding lectin (MBL) containing similar amino acid motif. CL-K1 can recognize specially several bacterial saccharides due to specific sugar-binding character. Elucidation of the role of two ancestor collectins of CL-K1 and CL-L1 could lead to see the biological function of collectin family.