Mie Inao

SNPs in the promoter region of the osteopontin gene as a marker predicting the efficacy of interferon-based therapies in patients with chronic hepatitis C.

BackgroundThe T-helper (Th)1 immune reaction is essential for the eradication of hepatitis C virus (HCV) during interferon (IFN) therapy in patients with chronic hepatitis C. Osteopontin is a cytokine crucial for the initiation of the Th1 response. Recently, we identified four single-nucleotide polymorphisms (SNPs) in the promoter region of the osteopontin gene (OPN), at nucleotide (nt) -155, -443, -616, and -1748, and suggested that the SNP at nt -443 was a marker reflecting hepatitis activity in patients with HCV. Therefore, we examined the possibility that SNPs in OPN were also markers predicting the therapeutic efficacy of IFN in patients with chronic hepatitis C.MethodsBlood was collected from 77 patients with chronic hepatitis C who had received either IFN monotherapy or IFN-ribavirin combination therapy (IFN-based therapies). SNPs in OPN, MxA, MBL, and LMP7 were analyzed by Invader assay.ResultsPromoter SNPs of OPN at nt -155, -616, and -1748 showed linkage disequilibrium at 100% to each other. Sustained virological response (SVR) was observed in 58% of all patients. The SVR rate was higher in patients with the G/G or G/A alleles in the OPN promoter SNP at nt -1748 than in those with A/A (85% vs 45%; P < 0.05). The SVR rate was also higher in patients with T/T at nt -443 than in those with C/C or C/T (86% vs 47%; P < 0.05). Such differences were particularly evident in patients with HCV genotype 1b who had a pretreatment viral load greater than 100 KIU/ml. All the patients who had G/G or G/A at nt -1748 and T/T at nt -443 obtained an SVR. On the other hand, there was no relationship between the efficacy of IFN-based therapies and SNPs in MxA, MBL, and LMP7, which had been shown to have association with the response to IFN monotherapies.ConclusionsSNPs in the promoter region of OPN may be useful as a marker to predict the efficacy of IFN-based therapies in patients with chronic hepatitis C, and further investigation regarding their real significance is warranted in a large series of patients.

Increased expression of osteopontin in activated Kupffer cells and hepatic macrophages during macrophage migration in Propionibacterium acnes-treated rat liver

Abstract: Osteopontin is an extracellular matrix component that can act as a chemokine to induce macrophage migration. The significance of osteopontin in macrophage infiltration into the liver was examined in rats given heat-killed Propionibacterium acnes. In normal rats, osteopontin mRNA expression in the liver was mini-mal, determined by quantitative-competitive reverse transcription-polymerase chain reaction (RT-PCR) assay. Northern blot analysis revealed that osteopontin mRNA was not expressed in Kupffer cells isolated from normal rats. When rats received heat-killed P. acnes intravenously, marked macrophage accumulation, forming granulomas, developed in the liver later than 3 days after the injection and its extent became maximal between 5 and 7 days. In these rats, osteopontin mRNA expression was increased in the liver later than 1 day (with its peak at 3 days after the injection), and the mRNA expression was increased markedly in Kupffer cells and hepatic macrophages isolated at 7 days. The mRNA expression of monocyte chemotactic protein-1 (MCP-1) and macrophage inflammatory protein-1α (MIP-1α), chemokines for monocytes and macrophages, was also increased in the liver of P. acnes-treated rats, with peak expression at 3 days. We conclude that osteopontin derived from Kupffer cells and hepatic macrophages may contribute to the infiltration of monocytes and macrophages into the liver cooperatively with the actions of MCP-1 and MIP-1α in P. acnes-treated rats.

ERK/MAPK-dependent PI3K/Akt phosphorylation through VEGFR-1 after VEGF stimulation in activated hepatic stellate cells.

Vascular endothelial growth factor (VEGF) can induce proliferation of endothelial cells through VEGFR-1 and VEGFR-2 as its receptors, but the intracellular signaling pathway via VEGFR-1 is still unclear. Previously we reported that stellate cells expressed VEGFR-1 exclusively during activation in the liver. In the present paper, the signaling pathway via VEGFR-1 was studied using rat stellate cells activated in vitro. Western blot analysis revealed that both ERK/mitogen-activated protein kinase (MAPK) and PI3K/Akt were phosphorylated in the cells activated by culture in Dulbeccos modified Eagle medium containing 10% fetal calf serum on plastic dishes for 9 days. When VEGF was added to the culture medium, the extent of such PI3K/Akt phosphorylation was increased despite that DNA synthesis and ERK/MAPK phosphorylation were unchanged in the cells. However, this up-regulation of PI3K/Akt phosphorylation was markedly diminished following addition of GFX and PD-98059, inhibitors for protein kinase C (PKC) and ERK/MAPK, respectively. Also, addition of GFX reduced phosphorylation of ERK/MAPK in the cells. It is suggested that VEGF may stimulate signal transduction of PI3K/Akt through VEGFR-1 dependently on activation of the PKC and ERK/MAPK pathway in activated hepatic stellate cells.

The mechanisms of hepatic sinusoidal endothelial cell regeneration: a possible communication system associated with vascular endothelial growth factor in liver cells.

Vascular endothelial growth factor (VEGF) has been shown to induce proliferation of sinusoidal endothelial cells in primary culture. To elucidate the mechanisms of sinusoidal endothelial cell regeneration in vivo, mRNA expression of VEGF and its receptors, flt‐1 and KDR/flk‐1, were studied in rat livers. Northern blot analysis revealed that VEGF‐mRNA was expressed in hepatocytes immediately after isolation from normal rats. In contrast, non‐parenchymal cells, including sinusoidal endothelial cells, expressed VEGF receptor‐mRNA. Vascular endothelial growth factor‐mRNA expression in hepatocytes was decreased during primary culture, but increased following a peak of DNA synthesis, induced by addition of epidermal growth factor or hepatocyte growth factor to the culture medium at 24 h of plating. In a 70% resected rat liver, VEGF‐mRNA expression increased with a peak at 72 h after the operation, and mRNA expression of VEGF receptors between 72 and 168 h. In such a liver, mitosis was maximal in hepatocytes at 36 h and in sinusoidal endothelial cells at 96 h. Also, mRNA expression of both VEGF and its receptors was significantly increased in carbon tetrachloride‐intoxicated rat liver compared with normal rat liver. Vascular endothelial growth factor expression was minimal in Kupffer cells isolated from normal rats, but marked in activated Kupffer cells and hepatic macrophages from the intoxicated rats. Vascular endothelial growth factor‐mRNA expression was also increased in activated stellate cells from these rats and in the cells activated during primary culture compared with quiescent cells. We conclude that increased levels of VEGF expression in regenerating hepatocytes may contribute to the proliferation of sinusoidal endothelial cells in partially resected rat liver, probably through VEGF receptors up‐regulated on the cells. Also, VEGF derived from activated Kupffer cells, hepatic macrophages and stellate cells may be involved in this proliferation in injured rat liver.

Development of rare resistance-associated variants that are extremely tolerant against NS5A inhibitors during daclatasvir/asunaprevir therapy by a two-hit mechanism

The virologic characteristics of resistance‐associated variants (RAVs) developing in patients receiving dual oral therapy with daclatasvir/asunaprevir, including those with previous triple therapy with simeprevir, were evaluated.

Development of rare RAVs that are extremely tolerant against NS5A inhibitors during daclatasvir/asunaprevir therapy Via a Two-Hit mechanism.

The virologic characteristics of resistance‐associated variants (RAVs) developing in patients receiving dual oral therapy with daclatasvir/asunaprevir, including those with previous triple therapy with simeprevir, were evaluated.

Massive liver necrosis after provocation of imbalance between Th1 and Th2 immune reactions in osteopontin transgenic mice.

BackgroundMassive liver necrosis can develop as a consequence of imbalance between T-helper (Th)1 and Th2 immune reactions in the liver. Osteopontin is a glycoprotein secreted for the initiation of the Th1 immune reaction, as well as for extracellular matrix formation and calcium deposition in the bone and kidney. Osteopontin is overexpressed in Kupffer cells, macrophages, and stellate cells activated in injured livers. We established transgenic mice expressing osteopontin exclusively in hepatocytes, using a vector containing human serum amyloid P component promoter. The relation of Th1/Th2 immune imbalance to massive liver necrosis was studied using these transgenic mice.MethodsTransgenic mice and C27BL/6 mice, wild-type controls of the transgenic mice, were given an intravenous injection of concanavalin-A, and the histological extent of liver injuries and plasma cytokine levels were evaluated.ResultsWhen the transgenic mice received concanavalin-A, massive necrosis and mononuclear cell infiltration developed in the liver, the extent of which was greater in the female mice than in the male mice. This treatment produced minimal liver injury and focal liver necrosis in male and female C57BL/6 mice. In these transgenic and control mice, plasma concentrations of interleukin (IL)-10 and interferon (IFN)-γ were increased after concanavalin-A treatment. However, the upregulation of plasma IL-10 concentration was smaller in the male and female transgenic mice than in the control mice, and the upregulation of the IFN-γ concentration was greater in the female transgenic mice than in the female control mice.ConclusionsTh1 and Th2 immune reactions were deranged after concanavalin-A treatment, with Th1 immunity predominating in transgenic mice expressing osteopontin in hepatocytes; this immunological imbalance may contribute to massive liver necrosis.

Therapeutic strategy for patients with bleeding rectal varices complicating liver cirrhosis

Although rupture of rectal varices is rarely encountered, it may provoke massive and fatal hemorrhage in patients with liver cirrhosis. We examined the clinical features of patients showing bleeding from rectal varices to establish a suitable therapeutic strategy for the lesions.

EFFECTS OF NEUROTROPIC PYRIMIDINE HETEROCYCLIC COMPOUND, MS-430, ON CULTURED HEPATIC PARENCHYMAL AND STELLATE CELLS

MS-430 is a novel synthetic pyrimidine derivative that stimulates regeneration of the nerve as a promoter for various growth factors such as epidermal growth factor (EGF) and nerve growth factor, and differentiation of astrocytes. The effects of MS-430 on the liver were tested using hepatocytes and stellate cells in primary culture isolated from rats. MS-430 enhanced EGF-induced DNA synthesis in hepatocytes while it alone failed to increase the basal DNA synthesis. Albumin mRNA expression in the cells and its amount in the medium were not changed by addition of EGF or MS-430 alone or both. Basic fibroblast growth factor (bFGF) increased DNA and but not collagen synthesis by hepatic stellate cells. Addition of MS-430 inhibited DNA synthesis by hepatic stellate cells at either presence or absence of bFGF, and collagen synthesis at the presence of bFGF. However, MS-430 had no effects on basal or bFGF-stimulated TGFbeta mRNA expression in the cells. These results suggest that MS-430 stimulated proliferation of hepatocytes as a comitogen for EGF without affecting albumin synthesis, and suppressed proliferation of activated hepatic stellate cells and their collagen synthesis without affecting TGFbeta expression.

PKC- and MAPK-independent upregulation of VEGF receptor expressions in human umbilical venous endothelial cells following VEGF stimulation.

Regulatory mechanisms of expressions of receptors for vascular endothelial growth factor (VEGF) are an important issue to clarify angiogenesis in the liver. Effects of exogenous VEGF on VEGF receptor expressions and intracellular signal transduction system were examined using human umbilical venous endothelial cells (HUVECs). HUVECs were cultured in BEM-2 solution containing VEGF for 5 days, and subjected to experiments 24 h after replacement of the medium to EBM-2 solution without VEGF. Addition of VEGF at concentrations up to 100 ng/ml increased the incorporation of 3H-thymidine into the DNA in the cells in a dose-related manner. Similar increases were found in mRNA expressions of VEGF receptors, VEGFR-1 and VEGFR-2, assessed by Northern blotting and in phosphorylation of mitogen activated protein kinase (MAPK) by Western blotting. Such VEGF-induced upregulation of DNA synthesis and phosporylation of MAPK in the cells were attenuated by the addition of GFX, a specific inhibitor of protein kinase C (PKC), but mRNA expression of VEGFR-2 evaluated by quantitative competitive RT-PCR method was not changed. It is suggested that exogenous VEGF upregulated mRNA expressions of VEGF receptors through intracellular signal transduction independent of the PKC-to-MAPK pathway in HUVECs.