Dynamically Programmed Switchable DNA Hydrogels Based on a DNA Circuit Mechanism.

Biological stimuli-responsive DNA hydrogels have attracted much attention in the field of medical engineering owing to their unique phase transitions from gel to sol through cleavage of DNA cross-linking points in response to specific biomolecular inputs. In this paper, a new class of biological stimuli-responsive DNA hydrogels with a dynamically programmed DNA system that relies on a DNA circuit system through cascading toehold-mediated DNA displacement reactions is constructed, allowing the catalytic cleavage of cross-linking points and main chains in response to an appropriate DNA input. The dynamically programmed DNA hydrogels exhibit a significant sharp phase transition from gel to sol in comparison to another DNA hydrogel showing noncatalytic cleavage of cross-linking points due to synchronization of the catalytic cleavage of cross-linking points and the main chains.

Attenuation of acute and chronic liver injury in rats by iron-deficient diet.

Oxidative stress due to iron deposition in hepatocytes or Kupffer cells contributes to the initiation and perpetuation of liver injury. The aim of this study was to clarify the association between dietary iron and liver injuries in rats. Liver injury was initiated by the administration of thioacetamide or ligation of the common bile duct in rats fed a control diet (CD) or iron-deficient diet (ID).

Heart myofibrillogenesis occurs in isolated chick posterior blastoderm: a culture model.

Early cardiogenesis including myofibrillogenesis is a critical event during development. -Recently we showed that prospective cardiomyocytes reside in the posterior lateral blastoderm in the chick embryo. Here we cultured the posterior region of the chick blastoderm in serum-free medium and observed the process of myofibrillogenesis by immunohistochemistry.

Erythrophagocytosis by liver macrophages (Kupffer cells) promotes oxidative stress, inflammation, and fibrosis in a rabbit model of steatohepatitis: implications for the pathogenesis of human nonalcoholic steatohepatitis.

Nonalcoholic steatohepatitis (NASH) is a progressive fibrotic disease, the pathogenesis of which has not been fully elucidated. Here, we report a molecular aspect of this disease elucidated using rabbits fed a cholesterol-rich high-fat diet and exhibiting insulin resistance. The liver in this model showed steatohepatitis with fibrosis and high mRNA expression for some cytokines, heme oxygenase-1, transforming growth factor-beta1, and collagen alpha1(I).

Rho kinase inhibitor Y27632 affects initial heart myofibrillogenesis in cultured chick blastoderm.

During early vertebrate development, Rho-associated kinases (ROCKs) are involved in various developmental processes. Here, we investigated spatiotemporal expression patterns of ROCK1 protein and examined the role of ROCK during initial heart myofibrillogenesis in cultured chick blastoderm. Immunohistochemistry showed that ROCK1 protein was distributed in migrating mesendoderm cells, visceral mesoderm of the pericardial coelom (from which cardiomyocytes will later develop), and cardiomyocytes of the primitive heart tube.

[Dissection of the heart: a useful guide to understanding the three-dimensional gross anatomy].

In order to understand the three-dimensional gross anatomy of the heart, it is important to observe the inner structures of the chambers and the spatial relation between the valves and the ventricles. In our dissecting laboratory, we designed a guide to dissection of the heart according to the following procedures. First, we observe the surface anatomy of the heart in the pericardial cavity, remove the heart and then identify the coronary vessels, open the four chambers and observe the intra-cardiac structures.

Derivation and characterization of hepatocytes from embryonic stem cells in vitro.

From a therapeutic perspective on liver, the use of embryonic stem (ES) technology in the generation of a large number of high-functional hepatocytes developed from ES cells for cell transplantation is anticipated. We have explored a three-dimensional culture system in which hepatocytes differentiated from mouse ES cells by transfection with the hepatocyte nuclear factor-3beta possess high metabolic functions that can be maintained long term.

Expression of NCAM in activated portal fibroblasts during regeneration of the rat liver after partial hepatectomy.

In the portal tract of the regenerating liver after partial hepatectomy, vascular and bile ductular remodeling takes place in response to the portal hyperdynamic state and parenchymal hyperplasia. In order to reveal phenotypical changes in the portal fibroblasts, we immunohistochemically investigated neural cell adhesion molecules (NCAM) and alpha smooth muscle actin (alphaSMA) expression and the ultrastructural changes in them during liver regeneration. In the control rat liver, portal fibroblasts were negative for both NCAM and alphaSMA.

Rho kinases regulate endothelial invasion and migration during valvuloseptal endocardial cushion tissue formation.

Rho-associated kinase (ROCK) is a downstream effector of small Rho-GTPases, and phosphorylates several substrates to regulate cell functions, including actin cytoskeletal reorganization and cellular motility. Endothelial-mesenchymal transformation (EMT) is a critical event in the formation of valves and septa during cardiogenesis. It has been reported that ROCK plays an important role in the regulation of endocardial cell differentiation and migration during mouse cardiogenesis (Zhao and Rivkees [2004] Dev.

Induction of initial cardiomyocyte alpha-actin--smooth muscle alpha-actin--in cultured avian pregastrula epiblast: a role for nodal and BMP antagonist.

During early cardiogenesis, endoderm-derived bone morphogenetic protein (BMP) induces the expression of both heart-specific transcription factors and sarcomeric proteins. However, BMP antagonists do not inhibit the expression of the "initial heart alpha-actin"--smooth muscle alpha-actin (SMA)--which is first expressed in the anterior lateral mesoderm and then recruited into the initial myofibrils (Nakajima et al. [2002] Dev.

Pit cells as liver-associated natural killer cells: morphology and function.

Pit cells are one type of hepatic sinusoidal cells, defined morphologically as large granular lymphocytes (LGLs) and functionally as liver-associated natural killer (NK) cells. They are situated inside the sinusoidal lumen, adhering to the endothelial cells and Kupffer cells. They contain multivesicular body-related dense granules and rod-cored vesicles.

Localization of lymphocyte apoptosis in murine lymphoid tissues after stimulation of natural killer T cells with alpha-galactosylceramide.

Alpha-galactosylceramide (alpha-GalCer) has been reported to induce activation-induced cell death (AICD) in natural killer T (NKT) cells. We undertook this study to demonstrate the distribution of AICD of NKT cells in the lymphoid tissues and differences in frequency between the central and peripheral lymphoid tissues, histologically and quantitatively analyzing the apoptotic figure in the murine spleen, lymph node, and thymus after alpha-GalCer treatment. Lymphocyte apoptosis was identified as a cluster of nuclei with chromatin condensation in hematoxylin-eosin-stained sections, and was confirmed by TUNEL staining, double staining for TUNEL and CD4, and electron microscopy.

Cytoglobin/STAP, its unique localization in splanchnic fibroblast-like cells and function in organ fibrogenesis.

Cytoglobin/stellate cell activation-associated protein (Cygb/STAP) consists of a new class of hexacoordinate globin superfamily, which was recently discovered by a proteome analysis on the rat hepatic stellate cells. Unlike haemoglobin, myoglobin, and neuroglobin, Cygb/STAP is ubiquitously expressed in several organs, although its detailed localization has not been clarified. Immunohistochemistry and immunoelectron microscopy revealed that Cygb/STAP is uniquely localized in fibroblast-like cells in splanchnic organs, namely the vitamin A-storing cell lineage, but neither in epithelial cells, endothelial cells, muscle cells, blood cells, macrophages, nor dermal fibroblasts.

Apoptosis of T cells in the hepatic fibrotic tissue of the rat: a possible inducing role of hepatic myofibroblast-like cells.

Apoptosis of T cells contributes to the immune homeostasis in inflamed organs. A prominent T-cell infiltration is usually seen in human chronic active hepatitis, being associated with liver fibrosis. In order to demonstrate T-cell apoptosis in the hepatic fibrotic tissue, we induced T-cell infiltration in the fibrotic liver of the rat by injecting concanavalin A (Con A), a T-cell mitogen.

Expression of SPARC by activated hepatic stellate cells and its correlation with the stages of fibrogenesis in human chronic hepatitis.

Secreted protein, acidic and rich in cysteine (SPARC), which functions in tissue remodeling, has been reported to be expressed by myofibroblasts in liver cirrhosis and hepatocellular carcinoma. This study aimed to reveal its expression in chronic hepatitis. Immuno-light and electron microscopy demonstrated that SPARC was expressed by nerve fibers and hepatic stellate cells (HSCs) in the liver parenchyma and myofibroblasts in the fibrous septa.

Characterization of human stellate cell activation-associated protein and its expression in human liver.

This study cloned cDNA of human homologue (hSTAP) of rat stellate cell activation-associated protein (rSTAP). hSTAP gene is on chromosome 17q and is composed of four exons. Various types of cells including hepatic stellate cells expressed hSTAP mRNA.

Development of hepatocytes from ES cells after transfection with the HNF-3beta gene.

We have attempted to generate embryonic stem (ES) cell-derived hepatocytes expressing liver-specific functional properties by use of ES cell technology. It was found that ES cells are allowed to differentiate into hepatocytes possessing high metabolic activities when hepatocyte nuclear factor (HNF)-3beta-transfected ES cells are cultured in alpha-MEM medium supplemented with 10% fetal bovine serum (FBS) and fibroblast growth factor (FGF)-2 in the three-dimensional cell culture system at 5% CO2. The differentiated cells induced albumin, triacylglycerol, urea, and glycogen synthesis as well as further expression of metabolic proteins and serum factors as markers of hepatocytic differentiation for at least 4 months.

In situ detection of lipid peroxidation and oxidative DNA damage in non-alcoholic fatty liver diseases.

Background/aims: Although oxidative stress is an important candidate in the pathogenesis of non-alcoholic fatty liver disease (NAFLD), the localization and pathological significance of oxidative stress-induced cellular damage in NAFLD remains unclear.

Methods: Hepatic expression of 4-hydroxy-2'-nonenal (HNE) and 8-hydroxydeoxyguanosine (8-OHdG), as reliable markers of lipid peroxidation and oxidative DNA damage, respectively, was immunohistochemically investigated in NAFLD and the results were compared with histological findings.

Results: While no HNE adducts were observed in control livers, they were frequently detected in NAFLD.

Fatty change in human hepatocellular carcinoma cell lines derived from patients with antibodies to hepatitis C virus.

Background/aims: Evidence suggesting a relationship between fatty change in normal or malignant hepatocytes and hepatitis C virus has gradually accumulated, but less is known about the relationship between cell proliferation and fatty change in human hepatocellular carcinoma.

Methodology: We studied the latter issue in two human hepatocellular carcinoma cell lines (OCUH-16 and Nuk-1) derived from hepatitis C virus-associated tumors. We examined the relationship between degree of fatty change assessed by oil-red-O staining and electron microscopy, actively proliferating cells counted using a monoclonal antibody to MIB-1 protein, and apoptotic cells counted using DNA nick-end labeling in the above two hepatocellular carcinoma cell lines with time lapse.

Evidence for a role of mast cells in the evolution to congestive heart failure.

Mast cells are believed to be involved in the pathophysiology of heart failure, but their precise role in the process is unknown. This study examined the role of mast cells in the progression of heart failure, using mast cell-deficient (WBB6F1-W/W(v)) mice and their congenic controls (wild-type [WT] mice). Systolic pressure overload was produced by banding of the abdominal aorta, and cardiac function was monitored over 15 wk.

Expression of Fas and Bcl-2 proteins and induction of apoptosis in human hepatocellular carcinoma cell lines.

Because the induction of apoptosis in cancer cells is very important in clinical management, it is useful to examine the association with the Fas-Fas ligand pathway and Bcl-2 protein family in apoptosis. We morphologically examined the expression of Fas and Bcl-2 proteins and induction of apoptosis by anti-Fas in four human hepatocellular carcinoma cell lines, PLC/PRF/5, Huh-6, and Huh-7, as well as OCUH-16, which was originally established in our university. Fas protein was expressed in 96% of OCUH-16 cells in cytoplasm, 24% of PLC/PRF/5 cells, 20% of Huh-6 cells, and no Huh-7 cells.