Mesenchymal Stem Cell-Derived Exosomes Mitigate Acute Murine Liver Injury via Ets-1 and Heme Oxygenase-1 Up-regulation.

BACKGROUND: Mesenchymal stem cells (MSCs)-derived exosomes have been previously demonstrated to promote tissue regeneration in various animal disease models. This study investigated the protective effect of exosome treatment in carbon tetrachloride (CCl4)-induced acute liver injury and delineated possible underlying mechanism. METHODS: Exosomes collected from conditioned media of previously characterized human umbilical cord-derived MSCs were intraperitoneally administered into male CD-1 mice with CCl4-induced acute liver injury. Biochemical, histological and molecular parameters were used to evaluate the severity of liver injury. A rat hepatocyte cell line, Clone-9, was used to validate the molecular changes by exosome treatment. RESULTS: Exosome treatment significantly suppressed plasma levels of AST, ALT, and pro-inflammatory cytokines, including IL-6 and TNF-, in the mice with CCl4-induced acute liver injury. Histological morphometry revealed a significant reduction in the necropoptic area in the injured livers following exosome therapy. Consistently, western blot analysis indicated marked elevations in hepatic expression of PCNA, c-Met, Ets-1, and HO-1 proteins after exosome treatment. Besides, the phosphorylation level of signaling mediator JNK was significantly increased, and that of p38 was restored by exosome therapy. Immunohistochemistry double staining confirmed nuclear Ets-1 expression and cytoplasmic localization of c-Met and HO-1 proteins. In vitro studies demonstrated that exosome treatment increased the proliferation of Clone-9 hepatocytes and protected them from CCl4-induced cytotoxicity. Kinase inhibition experiment indicated that the exosome-driven hepatoprotection might be mediated through the JNK pathway. CONCLUSION: Exosome therapy activates the JNK signaling activation pathway as well as up-regulates Ets-1 and HO-1 expression, thereby protecting hepatocytes against hepatotoxin-induced cell death.

Fucoidan enhances the effect of chemotherapeutic drug against drug-resistant lung cancer cells.

Development of adjuvant chemotherapy drugs against drug-resistant lung cancer cells is necessary. The use of non-toxic adjuvant natural product combined with chemotherapy drugs will be an important treatment mode in the future. The purpose of the study investigates that fucoidan enhances chemotherapy drug poisoning drug-resistant lung cancer cell. Drug-resistant lung cancer cells are established in the study. Cell culture, MTT assay, wound healing assay, gelatin zymography assay, DNA fragmentation assay, apoptosis assay, reverse transcription polymerase chain reaction (RT-PCR) western blot analysis was adopted. The results showed that fucoidan synergized with doxorubicin increased efficacy of poisoning drug-resistant lung cancer cells and enhanced the ability of doxorubicin to inhibit the migration of drug-resistant lung cancer cells. It was observed that fucoidan synergized with doxorubicin induced the increase of apoptosis and inhibited expression of MMP-9, LC3, Beclin-1 and ß-catenin in drug-resistant lung cancer cells. Fucoidan synergized with doxorubicin significantly inhibited proliferation, migration and metastasis of drug-resistant lung cancer cells. Fucoidan strengthened doxorubicin to induce apoptosis and autophagy of drug-resistant lung cancer cells. This study confirms that the combined use of fucoidan and chemotherapeutic drugs can effectively poison drug-resistant lung cancer cells.

Beta2-adrenergic receptor agonist inhibits keratinocyte proliferation by mechanisms involving nitric oxide.

INTRODUCTION: Beta2-adrenoceptors regulate proliferation of keratinocytes. Nitric oxide (NO) produced by keratinocytes through stimulation of nitric oxide synthase (NOS) mediates keratinocyte proliferation. Aim: In this study, the mechanism interaction ß-ARs and NO production on keratinocyte will be explored, and the important for proliferation will be studied. MATERIAL AND METHODS: To understand the relationship among ß2-adrenoceptors, NO production and proliferation in keratinocytes, the experiment is divided to two parts. In the first part of the experiment, keratinocytes are divided into five groups which are treated with 0 M, 10-7 M, 10-6 M, 5 × 10-6 M and 10-5 M isoproterenol, respectively. In the second part of the experiment, the keratinocytes are divided into five groups which are treated with 10-5 M isoproterenol and L-NMMA at doses of 0 M, 10-6 M, 5 × 10-6 M, 10-5 M and 5 × 10-5 M, respectively. We examine NOS expression, NO production, c-AMP level and proliferation in human keratinocytes. RESULTS: The results show that isoproterenol results in iNOS and ncNOS protein raised and the elevation of nitric oxide. L-NMMA can block the increase of iNOS and ncNOS protein expression and the ability to inhibit proliferation caused by isoproterenol. CONCLUSIONS: Beta2-adrenergic receptor agonist mediates nitric oxide synthase to affect keratinocyte proliferation in skin. The physiological and pathological relationship of these discoveries remains to be defined. These results can provide new possibilities in the therapy of integumentary disease conditions linked with the dysfunction of ß-AR-mediated NO production.

Oxidized low-density lipoprotein induced hepatoma-derived growth factor upregulation mediates foam cell formation of cultured rat aortic vascular smooth muscle cells.

Vascular smooth muscle cells (SMCs) are important vascular components that are essential for the regulation of vascular functions during vascular atherosclerogenesis and vascular injury. Oxidized low-density lipoprotein (oxLDL) is known to induce SMC activation and foam cell transformation. This study characterized the role of hepatoma-derived growth factor (HDGF) in oxLDL-induced foam cell formation in cultured primary rat aortic SMCs. OxLDL exposure significantly increased HDGF expression and extracellular release. It also upregulated atherogenic regulators in SMCs, including TLR4, MyD88, LOX-1, and CD36. Exogenous HDGF stimulation not only increased the expression of cognate receptor nucleolin, but also the innate immunity regulators TLR4/MyD88 and lipid metabolism regulators, including LOX-1 and CD36. Oil red O staining showed that HDGF did not initiate, but enhanced oxLDL-driven foam cell formation in SMCs. Further signaling characterization demonstrated that oxLDL evoked activation of PI3K/Akt and p38 MAPK signaling pathways, both of which were involved in the upregulation of HDGF, LOX-1, and CD36 induced by oxLDL. Gene knockdown experiments using LOX-1 targeted siRNA demonstrated that LOX-1 expression was critical for oxLDL-induced HDGF upregulation, while HDGF gene depletion completely abolished oxLDL-triggered TLR4, LOX-1, and CD36 overexpression and foam cell formation in SMCs. These findings strongly suggest that oxLDL-induced HDGF upregulation participates in subsequent LOX-1 and CD36 expression in aortic SMCs and mechanistically contributes to the formation of SMC-derived foam cells. The oxLDL/LOX-1/HDGF axis may serve as a target for anti-atherogenesis therapy.

Hepatoma-derived growth factor enhances osteoblastic transformation of rat aortic vascular smooth muscle cells in vitro.

AIMS: Vascular smooth muscle cells (VSMCs) are important regulators of vascular functions and their conversion to osteoblasts is a key to development of vascular calcification. This study aimed to characterize in vitro effect of hepatoma-derived growth factor (HDGF) on phenotypic conversion of cultured aortic VSMCs into osteoblast-like cells. MATERIALS AND METHODS: Cell proliferation and migration assays were used to examine cell behaviors. Western blotting, alkaline phosphatase activity and calcium staining were used to evaluate osteoblastic marker expression and function, respectively. KEY FINDINGS: Recombinant HDGF treatment enhanced VSMC growth and motility. Treatment of osteogenic medium (OM) increased expression of not only HDGF but also osteoblastic markers, including Runx2 and osteopontin (OPN), while VSMC marker α-smooth muscle actin (α-SMA) declined. Coincidentally, HDGF and OM treatment alone stimulated signaling activities in both PI3K/Akt and MAPK pathways. Conversely, inhibition of Akt and p38 significantly blocked the OM-upregulated HDGF, Runx2, and OPN expression and NF-κB phosphorylation, but did not reversed the α-SMA downregulation, implicating the involvement of Akt and p38 activities in the osteoblastic transformation of VSMCs. Small interfering RNA-mediated HDGF gene silencing effectively prevented the Runx2 and OPN upregulation, alkaline phosphatase activation, and calcium deposition, but did not affect the α-SMA levels in the transformed cells, supporting the involvement of HDGF in regulation of Runx2 and OPN expression. SIGNIFICANCE: In conclusion, in synergism with other osteogenic factor, HDGF may promote the progression of osteobastic transformation of VSMCs via Akt and p38 signaling pathways and contribute to vascular calcification in arteriosclerosis. CHEMICAL COMPOUNDS STUDIED IN THIS STUDY: HDGF (PubChem CID:); LY294002 (PubChem CID: 3973); PD98059 (PubChem CID: 4713); SB203580 (PubChem CID: 176155); SB431542 (PubChem CID: 4521392); SP600125 (PubChem CID: 8515); Wortmannin (PubChem CID: 312145).

Antiaging and smoothness-improving properties of farnesol-based facial masks on rat skin exposed to ultraviolet B.

BACKGROUND: Farnesol is an acyclic sesquiterpene presents in various natural sources including fruits, vegetables, and herbs. In this study, we successfully prepared a farnesol-containing gel with ultraviolet B-screening and skin-repairing capabilities. Furthermore, the advantageous potential of farnesol-containing facial masks for UVB-caused sunburnt skin was evaluated. AIMS: Thus, the objectives of this study are to design and prepare optimal facial masks possessing collagen production and smoothness-enhancing capabilities for the skin. METHODS: A series of formulations consisting of hydroxypropyl methylcellulose, hyaluronan, and farnesol were used to prepare the facial masks. The effects of the facial masks on collagen production by skin fibroblasts in vitro were examined. The effects of the prepared masks on collagen synthesis, smoothness, and inflammation of the skin were further evaluated in vivo using two modes (mask administration interspersed with UVB exposure and mask administration after UVB exposure) of a rat model. RESULTS: Facial masks containing both 0.3 and 0.8 mM farnesol improved skin smoothness and enhanced collagen content and arrangement in the skin of rats with mask administration interspersed with and after UVB exposure. The masks containing 0.8 mM farnesol exerted the greatest effects on collagen production/arrangement and smoothness improvement in vivo model. Histopathologically observed inflammation was alleviated, and interleukin (IL)-6 was decreased in the 0.8 mM farnesol-containing facial mask-covered skin compared with that without facial masks. CONCLUSIONS: The farnesol-containing facial masks prepared in this study may have collagen production-increasing, smoothness-improving, and anti-inflammatory properties for UVB-caused sunburn; thus, farnesol is potentially a beneficial component in facial masks.

Evaluation of the UVB-screening capacity and restorative effects exerted by farnesol gel on UVB-caused sunburn.

Farnesol, a natural 15-carbon organic compound, has various microbiological and cellular activities. It has been found to exert apoptosis-inducing effects against carcinoma cells as well as antiallergic and anti-inflammatory effects in vivo. In the current study, a series of formulations composed of various concentrations of hydroxypropyl methylcellulose (HPMC) with the addition of hyaluronan (HA) and xanthan gum (XG) was designed to evaluate the UVB-screening and H2 O2 -eliminating effects of farnesol in normal fibroblasts. Farnesol at 0.005, 0.0075, and 0.01% exhibited significant capacity for H2 O2 scavenging; at 0.0025%, it showed insignificant effects. Under 120-min UVB exposure, screening with plural gel composed of 0.0025% farnesol, 0.5% HA, and 0.5% XG containing 1.5% or 2% HPMC retained normal fibroblast viability. After 60-min exposure to UVB, screening with plural gel composed of farnesol, HA, XG, and 0.5%, 1.0%, 1.5%, or 2% HPMC decreased the ratio of the G1 phase and increased ratio of the S phase in comparison with the accumulated cell cycle of the normal fibroblasts without screening. The gel with 2% HPMC displayed the strongest cell cycle-reversal ability. In vivo histopathological results showed that the prepared plural gels with 0.5% or 2% HPMC and farnesol, HA, and XG had greater antiphotoaging and reparative effects against UVB-induced changes and damage in the skin. In conclusion, the current in vitro and in vivo results demonstrated that the prepared plural composed of 0.0025% farnesol, 0.5% HA, 0.5% XG, and 2% HPMC possessed the greatest UVB-screening capacity and the strongest restorative effects on UVB-induced sunburned skin.

Lipopolysaccharides induce Smad2 phosphorylation through PI3K/Akt and MAPK cascades in HSC-T6 hepatic stellate cells.

AIMS: Endotoxemia and its pro-fibrogenic signaling play a significant role in the development of hepatic fibrosis. This study investigated whether lipopolysaccharide (LPS) directly activate cultured HSC-T6 hepatic stellate cells (HSCs) through triggering Smad-dependent pro-fibrogenic signaling pathway. MAIN METHODS: Direct cell counting and assays for cell proliferation and migration were used to measure the effects of LPS on HSC behaviors. Quantitative PCR, Western blot, and gelatin zymography were used to quantify the molecular effects of LPS on expression of HSC activation markers and signaling activity. KEY FINDINGS: Long-term exposure to LPS exhibited moderately stimulatory effect on HSC cell growth. A wound-healing cell migration assay showed that LPS suppressed HSC-T6 cell migration. qPCR and Western blotting detection indicated that LPS treatment induced upregulation of type I and IV collagens, α-smooth muscle actin (α-SMA), and matrix metalloproteinase-9 (MMP-9). Gelatin zymography confirmed that LPS elevated MMP-9, but not MMP-2 gelatinolytic activity. Moreover, LPS immediately stimulated Akt, EKR1/2, JNK, p38 MAPK, and Smad2 hyperphosphorylation, supporting that LPS directly triggers pro-fibrogenic Smad signaling cascade without TGF-ß1 stimulation. Kinase blockade experiments demonstrated the involvement of PI3K/Akt, JNK, p38 MAPK, but not ERK1/2 signaling activation in the LPS-elicited Smad2 phosphorylation as well as the overexpression of type I collagen and α-SMA in HSC-T6 cells. SIGNIFICANCE: These findings demonstrate that LPS exerts pro-fibrogenic effect through activation and transformation of HSCs. The tissue-remodeling effect of LPS may be attributable to its ability to activate non-canonical Smad pathway through PI3K/Akt and MAPK signaling cascades.

Various UVB doses affect change of raf kinase inhibitor protein, nitric oxide and proliferation in keratinocytes.

UVB is a potent modulator of cell growth and differentiation in the skin. The UVB irradiation has been used in treating hyperproliferative dermatoses. Otherwise, UVB radiation is also the major risk factor for developing skin cancer. Nitric oxide (NO) has been suggested to be a physiological modulator of cell proliferation. Raf-1 kinase inhibitory protein (RKIP) was involved in cell growth, transformation, and differentiation. The purpose of this study was to search for the possible cause of UVB-inhibited hyperplasia and UVB-resulted hyperproliferation. We evaluated various UVB dose whether affect the expression of RKIP, iNOS, NO and proliferation in keratinocyte. Normal human keratinocytes were treated with UVB dose of 40mJ/cm2, 80mJ/cm2, 120mJ/cm2, 160mJ/cm2 and 0mJ/cm2 (control group) respectively. The results showed that RKIP, iNOS and NO of keratinocytes with doses of 40mJ/cm2 and 80mJ/cm2 UVB treatment significantly higher than control group (P<0.01). The proliferation of keratinocyte with doses of 40mJ/cm2 and 80mJ/cm2 UVB treatment was significantly lower than control group (P<0.01). However, RKIP, iNOS and NO of keratinocytes with doses of 120mJ/cm2 and 160mJ/cm2 UVB treatment significantly lower than control group (P<0.01). The proliferation of keratinocyte with doses of 120mJ/cm2 and 160mJ/cm2 UVB treatment was significantly higher than control group (P<0.01). In conclusion, these results showed that the different UVB dosages induced various alteration of RKIP, NO, iNOS and proliferation may provide important information on the therapeutic molecular mechanism of UVB-inhibited hyperplasia and UVB resulted hyperproliferation.

RKIP expression of liver and kidney after arsenic exposure.

Arsenic is associated with cancers of kidney and liver. Raf kinase inhibitor protein (RKIP) has been identified as a member of a novel class of molecules that suppress the metastatic spread of tumors. In order to investigate the effect of arsenic to RKIP of liver and kidney, the expression of RKIP of liver and kidney with As (III) was explored in this study. Thirty male mice were chronically fed with 42.5 ppm, 85 ppm NaAsO2 and water for 180 days. The kidney and liver accumulation levels of As (III) in mice were determined by electro-thermal atomic absorption spectrometry. The method of RT-PCR, Western blotting analysis and immunohistochemistry were used to determine gene expression and protein expression of RKIP. The results showed that arsenic level was significantly increased in kidney and liver of As (III)-exposed mice as compared with control group. The gene expression and protein expression of RKIP was significantly decreased in kidney and liver of As (III)-exposed mice in comparison with these of control mice. These data suggested that RKIP decrease of liver and kidney with As (III) may be dangerous index in formation of cancer. © 2016 Wiley Periodicals, Inc. Environ Toxicol 32: 1079-1082, 2017.

The expression of RKIP, RhoGDI, galectin, c-Myc and p53 in gastrointestinal system of Cr(VI)-exposed rats.

Hexavalent chromium (CrVI) is considered to be a risk factor in the formation of human cancer. Raf kinase inhibitor protein (RKIP), Rho-GDIα, galectin, c-Myc and p53 play important roles in cancer formation. The purpose of this study was to determine if Cr(VI) induces the formation of gastrointestinal cancer. We explored the expression of RKIP, Rho-GDIα, galectin, c-Myc and p53 in the colon and stomach in rats exposed to chromium (CrVI). Thirty Wistar rats were divided into six groups which were chronically fed with 250, 500, 750, 1000 and 1250 ppm Na(2) Cr(2) O(7) and water for 60 days. The level of Cr(VI) was determined by electrothermal atomic absorption spectrometry. The expression of RKIP, Rho-GDIα, galectin, c-Myc and p53 of stomach and colon was measured by western blot. The gene expression of RKIP, Rho-GDIα, galectin, c-Myc and p53 of the stomach and colon was determined by RT-PCR. The results showed that the expression of p53 and Rho-GDIα was decreased in the stomach and colon of rats with Cr(VI) treatment. The expression of RKIP was decreased in the stomach and colon of rats treated with high-dose Cr(VI). The expression of c-Myc and gelectin-1 was increased in the stomach and colon of rats with Cr(VI) treatment. We concluded that the anomalous expression of RKIP, Rho-GDIα, galectin, c-Myc and p53 might be a dangerous index of cancer formation in the stomach and colon of rats with Cr(VI) exposure.

Hexavalent chromium inhibited the expression of RKIP of heart in vivo and in vitro.

BACKGROUND: Chromium (Cr) is considered to be a risk factor to the cardiovascular effects of fine particulate matter components to PM2.5 from traffic in highway patrol officers. RKIP (raf kinase inhibitor protein) is a physiological inhibitor of GRK-2 (G-protein-coupled receptor kinase 2) and affects ß-adrenergic signaling and contractile activity in cardiomyocytes. OBJECTIVES: In this study, we explored the change of RKIP in heart of chromium (VI)-exposed rats and cultured myocardial cells with chromium (VI) treatment. METHOD: Wistar rats were divided into six groups which were chronically fed with 250, 500, 750, 1000, and 1250 ppm Na(2)Cr(2)O(7) and water for 60 days, respectively. Na(2)Cr(2)O(7) dose of 0.25, 0.5, 1.5, 3, 4.5, and 0 ppm (control group) was applied in cultured myocardial cells. The level of heart Cr (VI) was determined by electrothermal atomic absorption spectrometry. The expression of RKIP was measured by Western blot method. The MTT assay was used to measure the toxicity of myocardial cells with Cr (VI) treatment. The apoptosis test of myocardial cells was determined by caspase-3 colorimetric assay kit. RESULT: The result showed that the expression of RKIP in heart (in vivo) and myocardial cells (in vitro) was decreased following Cr (VI) dose-dependent treatment. CONCLUSION: We suggested that the decrement of RKIP of heart and myocardial cells with Cr (VI) treatment resulted in the function of cardiovascular system decreased.

High concentration of magnolol induces hepatotoxicity under serum-reduced conditions.

Although magnolol is cytoprotective against warm ischemia/reperfusion injury, its effect on cold preservation has not been fully investigated. This study aimed at examining whether magnolol maintains the liver graft integrity after cold preservation and elucidating the underlying mechanisms in terms of apoptotic signaling under both normothermic and hypothermic conditions. After being preserved in Ringer's lactate (RL) at 4 degrees C for 6h ex vivo, the magnolol-treated grafts demonstrated significantly higher AST, ALT, and LDH levels in perfusates than those from negative controls. TUNEL staining showed no difference in the number of apoptotic nuclei in both groups, whereas a more intense apoptotic signal in magnolol-treated grafts was shown as compared with the controls. In vitro data showed no significant difference in viability of RL-preserved clone-9 hepatocytes between the magnolol-treated and control groups, while magnolol pretreatment at 30min before cold preservation prominently induced hepatocyte cell death. RT-PCR and Western blotting analyses revealed a suppression in Bcl-2, but an up-regulation in Bax expression in clone-9 cells after magnolol treatment. Magnolol suppressed the ratios of NF-kappaB to I-kappaBalpha protein contents and I-kappaBalpha phosphorylation induced by TNF-alpha, and potentiated mitochondrial cytochrome c release and subsequent caspase-3 cleavage. Conversely, caspase-3 inhibitor attenuated magnolol-induced hepatotoxicity. We concluded that magnolol could not protect liver grafts from cold ischemia/reperfusion injury. High concentration of magnolol under serum-reduced conditions attenuates NF-kappaB-mediated signaling and induces intrinsic apoptotic pathway, thereby inducing in vitro hepatotoxicity.

Nitric oxide enhances expression of raf kinase inhibitor protein in keratinocytes.

Several reports have focused on the potential of nitric oxide (NO) to influence the proliferation and differentiation cascade in a number of mammalian cells. The purpose of this study was to determine the relationship between expression of raf kinase inhibitor protein (RKIP) and proliferation in keratinocyte with NO treatment. Normal human keratinocytes were treated with SNAP (NO donor) doses of 10(-7), 10(-6), 10(-5), 10(-4) and 0 m (control group) separately. Expression of protein and mRNA of RKIP, cell proliferation and apoptosis have been measured. These results showed that elevated expression of RKIP in keratinocyte with NO treatment may contribute to the pathological and physiological features of NO-inhibited proliferation.

Defective adrenergic responses in patients with arsenic-induced peripheral vascular disease.

Blackfoot disease is an endemic arsenic-induced peripheral vascular disease in southern Taiwan. The main pathologic feature is atherosclerosis, which may relate to imbalances of the adrenergic system. The purpose of this study is to investigate the peripheral adrenergic responses of patients with blackfoot disease. Eight patients with blackfoot disease and four age-matched healthy controls were enrolled in this study. Baseline cutaneous perfusion was measured with a laser Doppler flowmeter. The response of alpha-adrenoceptors in the cutaneous microcirculation was assessed with laser Doppler flowmetry with iontophoresis of phenylephrine into the nailfold. In vitro binding with (125)I-cyanopindolol determined beta-adrenoceptor density in lymphocytes. The cyclic adenosine monophosphate (cAMP) level at baseline and after isoproterenol stimulation reflects lymphocyte beta-adrenergic responsiveness. Results revealed persistently decreased skin perfusion in patients with blackfoot disease. In contrast, there was a transient decrease in skin perfusion in healthy controls after iontophoresis of phenylephrine. Both beta-2 receptor density and isoproterenol-stimulated cAMP levels in lymphocytes decreased. Increased peripheral alpha-adrenergic response and decreased beta-2-adrenergic response are related to increased vascular tone and result in atherosclerosis. Our findings of accentuated alpha-adrenergic response in microcirculation and decreased lymphocyte beta-2-adrenoceptor response play an important role in the pathogenesis of atherosclerosis in blackfoot disease.

Genetic and cellular characterizations of human TCF4 with microsatellite instability in colon cancer and leukemia cell lines.

It has been reported that the mutational inactivation of the adenomatous polyposis coli (APC) and beta-catenin genes play important roles in colorectal carcinogenesis. However, alteration of the components in the Wnt signaling pathway in colorectal cancer (CRC) with microsatellite instability (MSI) has been elucidated. To define the precise role of the Wnt signaling components in CRC and leukemia cell lines with MSI, mutational analyses of the T cell factor 4 (TCF4) genes were performed. Here we describe for the first time a TCF4 MSI+ phenotype in leukemia cell lines except in colon cancer cell lines. Moreover, we found that these cell lines exhibited deletion and insertion of 1-2A in an (A)9 repeat so as to result in (A)7, (A)8, (A)10 and (A)11 repeat, respectively. To characterize the cellular function of these special TCF4 mutant clones, transient transfection and fluorescent microscopy were analyzed and the results revealed that the TCF4 frameshift gene products all localized in nuclei. Surprisingly, these TCF4 frameshift mutants lost transcriptional activity with beta-catenin and down-regulate the target gene expression. These results delineate a novel role for MSI+TCF4 in leukemia and colon cancer progression.

Beta-adrenergic receptor density and adenylate cyclase activity in lead-exposed rat brain after cessation of lead exposure.

To understanding the reversible or irreversible harm to the beta-adrenergic system in the brain of lead-exposed rats, this study sets up an animal model to estimate the change in the sympathetic nervous system of brain after lead exposure was withdrawn. We address the following topics in this study: (a) the relationship between withdrawal time of lead exposure and brain beta-adrenergic receptor, blood lead level, and brain lead level in lead-exposed rats after lead exposure was stopped; and (b) the relationship between lead level and beta-adrenergic receptor and cyclic AMP (c-AMP) in brain. Wistar rats were chronically fed with 2% lead acetate and water for 2 months. Radioligand binding was assayed by a method that fulfilled strict criteria of beta-adrenergic receptor using the ligand [125I]iodocyanopindolol. The levels of lead were determined by electrothermal atomic absorption spectrometry. The c-AMP level was determined by radioimmunoassay. The results showed a close relationship between decreasing lead levels and increasing numbers of brain beta-adrenergic receptors and brain adenylate cyclase activity after lead exposure was withdrawn. The effect of lead exposure on the beta-adrenergic system of the brain is a partly reversible condition.

The change of beta-adrenergic system after cessation of lead exposure.

For understanding a reversible or irreversible harm of beta-adrenergic system in lead induced cardiovascular disease (hypertension), We set up animal model to estimate the change of blood pressure and sympathetic nervous system after lead exposure withdrawn in the study. We address three topics in this study: (a) the relationship between withdrawal time of lead exposure and beta-adrenergic receptor, plasma catecholamine level, blood pressure, and lead level in heart, aorta, and kidney in lead-induced hypertensive rats after lead exposure stopped; (b) the relationship between blood pressure and beta-adrenergic receptor in heart, aorta, and kidney; (c) the estimation of relationship between lead withdrawn and the variation of beta-adrenergic system. Wistar rats were chronically fed with 2% lead acetate (experimental group) and water (control group) for 2 months. The rats were divided into 8 groups by withdrawal time of lead exposure stopped. Plasma catecholamine level was measured by high-performance liquid chromatography. Radioligand binding assay was measured by a method that fulfilled strict criteria of beta-adrenergic receptor using the ligand [125I]iodocyanopindolol. The levels of lead were determined by electrothermal atomic absorption spectrometry. The results showed that a close relation between reduced lead level and the plasma catecholamine level decreased, aorta beta-adrenergic receptor increased, kidney beta-adrenergic receptor diminished, heart beta-adrenergic receptor increased, and blood pressure dropped after lead exposure withdrawn. The study on the regulation of beta-adrenergic system in lead-induced hypertension after lead withdrawn might also provide insight about the nature of this disease state.

Expression of nitric oxide synthases in keratinocytes after UVB irradiation.

The importance of nitric oxide (NO) in mediating vasodilation, neurotransmission, and immune and inflammatory responses has been demonstrated. Human keratinocyte express inducible nitric oxide synthase (iNOS) and the neuronal constitutive isoform of NOS (ncNOS). We established an in vitro model in keratinocytes to investigate changes in NO, iNOS and ncNOS expression after UVB exposure. We demonstrated a large induction of NO after UVB exposure and that the source of NO produced in UVB-exposed keratinocytes was increased expression of iNOS and ncNOS. The increased NO production with increased expression of iNOS and ncNOS may contribute to the pathological and physiological features of UVB-induced erythema and skin inflammation.