One of the early events in development of liver cancer is a neutralization of tumor suppressor proteins Rb, p53, HNF4α and C/EBPα. The elimination of these proteins is mediated by a small subunit of proteasome, gankyrin, which is activated by cancer. The aim of this study was to determine mechanisms which repress gankyrin in quiescent livers and mechanisms of activation of gankyrin in liver cancer. We found that farnesoid X receptor, FXR, inhibits expression of gankyrin in quiescent livers by silencing the gankyrin promoter through HDAC1-C/EBPβ complexes. C/EBPβ is a key transcription factor which delivers HDAC1 to gankyrin promoter and causes epigenetic silencing of the promoter. We show that down-regulation of C/EBPβ in mouse hepatoma cells and in mouse livers reduces C/EBPβ-HDAC1 complexes and activates the gankyrin promoter. Deletion of FXR signaling in mice leads to de-repression of the gankyrin promoter and to spontaneous development of liver cancer at 12 months of age. DEN-mediated liver cancer in WT mice also involves the reduction of FXR and activation of gankyrin. Examination of liver cancer in old mice and liver cancer in human patients revealed that FXR is reduced; while gankyrin is elevated during spontaneous development of liver cancer. Searching for animal models with altered levels of FXR, we found that long-lived Little mice have high levels of FXR and do not develop liver cancer with age and after DEN injections due to failure to activate gankyrin and eliminate Rb, p53, HNF4α and C/EBPα proteins. CONCLUSION FXR prevents liver cancer by inhibiting the gankyrin promoter via C/EBPβ-HDAC1 complexes leading to subsequent protection of tumor suppressor proteins from degradation.
Liver cancer is the fifth most common cancer. A highly invasive surgical resection of the liver tumor is the main approach utilized to eliminate the tumor. Mechanisms that terminate liver regeneration when the liver reaches the original size are not known. The aims of this work were to generate the animal model which fails to stop liver regeneration after surgical resections and elucidate mechanisms which are involved in termination of liver regeneration. Because epigenetic control of liver functions has been previously implicated in the regulation of liver proliferation, we have generated C/EBPα-S193A knockin mice, which have alterations in formation of complexes of C/EBP family proteins with chromatin remodeling proteins. The C/EBPα-S193A mice have altered liver morphology and altered liver functions leading to changes of glucose metabolism and blood parameters. Examination of proliferative capacity of C/EBPα-S193A livers showed that livers of S193A mice have a higher rate of proliferation after birth, but stop proliferation at the age of 2 months. These animals have increased liver proliferation in response to liver surgery as well as CCl4-mediated injury. Importantly, livers of C/EBPα-S193A mice fail to stop liver regeneration after surgery when livers reach the original, pre-resection, size. The failure of S193A livers to stop regeneration correlates with the epigenetic repression of key regulators of liver proliferation C/EBPα, p53, FXR, SIRT1, PGC1± and TERT by C/EBPβ-HDAC1 complexes. The C/EBPβ-HDAC1 complexes also repress promoters of enzymes of glucose synthesis PEPCK and G6Pase. Conclusions Our data demonstrate that a proper co-operation of C/EBP and chromatin remodeling proteins is essential for the termination of liver regeneration after surgery and for maintenance of liver functions.
This study was conducted to identify the effectiveness of platelet-rich plasma (PRP) and efficacy of intralesional injection as a method of application to acute cutaneous wounds in dogs. Healthy adult beagles (n = 3) were used in this study. Autologous PRP was separated from anticoagulant treated whole blood in three dogs. Cutaneous wounds were created and then treated by intralesional injection of PRP in the experimental group, while they were treated with saline in the control group on days 0, 2 and 4. The healing process was evaluated by gross examination throughout the experimental period and histologic examination on day 7, 14 and 21. In PRP treated wounds, the mean diameter was smaller and the wound closure rate was higher than in the control. Histological study revealed that PRP treated wounds showed more granulation formation and angiogenesis on day 7, and faster epithelialization, more granulation formation and collagen deposition were observed on day 14 than in control wounds. On day 21, collagen deposition and epithelialization were enhanced in PRP treated groups. Overall, PRP application showed beneficial effects in wound healing, and intralesional injection was useful for application of PRP and could be a good therapeutic option for wound management in dogs.
A facile method of preparing triple‐modality, optical–nuclear–magnetic imaging probes using radiolabeled superparamagnetic nanoparticles is developed. Cerenkov luminescence imaging based on radionuclides showed great potential as a new optical imaging modality. The complementary nature of the optical/PET/MR hybrid nanoprobes facilitated non‐invasive differentiation between tumor‐metastasized sentinel lymph nodes (SLNs) and tumor‐free SLNs.
Helicobacter pylori infection has been reported to be very common in patients with chronic liver diseases, including cirrhosis. To elucidate the pathological effect of H. pylori infection on the progression of hepatic fibrosis, C57BL/6 mice and Sprague-Dawley rats were orally inoculated with H. pylori, and hepatic fibrosis was induced with carbon tetrachloride (CCl 4 ) administration. We observed the histopathological changes and the presence of H. pylori genes by PCR in the liver. Significant increase in the fibrotic score as well as in serum alanine aminotransferase and aspartate aminotransferase levels was shown in the CCl 4 þ H. pylori group compared with that in the CCl 4 -treated group. Compared with the CCl 4 -treated group, a-smooth muscle actin and transforming growth factor-b1 were enhanced; however, senescence marker protein-30, a multifunctional protein protecting hepatocytes against oxidative stress and apoptosis, was suppressed in the CCl 4 þ H. pylori group. The 16S rRNA (400 bp) was demonstrated by PCR for H. pylori genes from genomic DNA extracted from the liver, and H. pylori-infected mice showed 93.8% (15 of 16) seropositivity by contrast with seronegativity in all H. pylori-noninfected mice. In addition, immunohistochemical study against H. pylori showed positive antigen fragments in the liver of the infected groups. Consequently, our data suggest that H. pylori infection could be an important contributing infectious factor to the development of liver cirrhosis.
Three dead dogs were brought to the College of Veterinary Medicine, Kyungpook National University for study. Clinically, all the dogs showed emaciation, anorexia, depression, hemorrhagic vomiting and diarrhea for 7~10 days before death. All the clinical signs were first noted for about one month after feeding the dogs with commercial diets. At necropsy, all 3 dogs had severe renal damage with the same green-yellowish colored nephroliths in the renal pelvis. They also showed systemic hemorrhage and calcification of several organs, which might have been induced by uremia. Microscopically, necrosis, calcification and calculi were detected in the renal tubules, and especially in the proximal convoluted tubules and collecting ducts of the kidney. These findings were supportive of a mycotoxic effect, and especially on their kidneys. However, the precise cause of the toxic effect in these cases of canine renal failure could not be determined.
We demonstrate that dramatically improved hole injection can be achieved by inserting a very thin C60 film between the indium tin oxide (ITO) electrode and N,N′-diphenyl-N,N′-bis(1,1′-biphenyl)-4,4′-diamine (NPB) layer. This result is ascribed to the formation of an interfacial dipole layer of buckminsterfullerene (C60) on the ITO electrode. The dipole layer induces the surface potential shift that contributes to improve the charge injection efficiency. The chemical shift was downward to help lower the hole injection energy barrier from the ITO electrode to the NPB layer, consistent with the moderately strong electron accepting nature of C60. The enhanced-charge injection provides a simple way of reducing the power consumption of organic electronic devices for real applications.
Background: Older patients are more sensitive to drug-mediated development of liver disorders. Results: Age and CCl 4 treatments change expression of C/EBP proteins leading to repression of key regulators of liver biology. Conclusion:The age-associated alterations of C/EBP proteins cause severe liver injury after CCl 4 treatments. Significance: Understanding of mechanisms of age-associated severe liver injury is important for development of therapeutic approaches.
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