Hyun-Ji Choi

Time-course changes in the expression levels of miR-122, -155, and -21 as markers of liver cell damage, inflammation, and regeneration in acetaminophen-induced liver injury in rats

Drug-induced liver injury (DILI) is a significant threat to patient health and a major concern during drug development. Recently, multiple circulating microRNAs (miRNAs) have been reported to be potential biomarkers for DILI. To adapt and validate miRNAs for clinical use, we investigated the time-course changes in miR-122 expression levels in an acetaminophen-induced liver injury model in rats. In addition, miR-155 and miR-21 were evaluated as makers of inflammation and regeneration, respectively, to characterize liver status. Our results revealed that miR-122 is an early and sensitive biomarker of hepatocellular injury at a stage when alanine transaminase, aspartate transaminase, and total bilirubin were not detectable. However, no significant differences in the expression levels of other miRNAs (miR-155 and -21) were observed between treatment and vehicle groups. Collectively, these time-course changes in the expression levels of miRNAs may be useful as markers for clinical decision-making, in the diagnosis and treatment of DILI.

Carcinogenicity study of CKD-501, a novel dual peroxisome proliferator-activated receptors α and γ agonist, following oral administration to Sprague Dawley rats for 94–101 weeks

CKD-501 is a peroxisome proliferator-activated receptor (PPAR) agonist. The current study was conducted in Sprague Dawley (SD) rats for 94-101 weeks to investigate the carcinogenic potential of CKD-501. 60 males received 0, 0.03, 0.12, or 1.0mg/kg/day, which was changed after 66 weeks to 0.24 mg/kg/day due to increased mortality, while 60 females received 0, 0.03, 0.06, or 0.12 mg/kg/day throughout the study period. After switching the dosage, no significant changes in the survival rates were observed. Non-neoplastic lesions such as bladder transitional cell hyperplasia and a diminished corpus luteum were observed in females administered 0.12 mg/kg/day and the right chamber dilation and left ventricular hypertrophy were increased dose dependently in both males and females. Non-neoplastic lesions such as bone marrow hypoplasia and fat cell proliferation and neoplastic lesions such as lipomas and liposarcomas observed in males and/or females were considered expected pharmacological effects for this compound. Compared to rosiglitazone, CKD-501 had a 4.4-fold higher margin of safety for tumor induction and did not cause bladder carcinoma as was observed with pioglitazone.

CTRP1 protects against diet-induced hyperglycemia by enhancing glycolysis and fatty acid oxidation.

Complement-C1q/tumor necrosis factor-α related protein 1 (CTRP1) is a 35-kDa glycoprotein that is secreted from various tissues. Although CTRP1 is highly increased in patients with type II diabetes and obesity, the metabolic roles of CTRP1 remain largely unknown. To unveil the physiological roles of CTRP1 in vivo, CTRP1 transgenic (TG) mice were challenged by a high-fat diet (HFD) and a high-sucrose drink (HS). Homeostatic model assessment-estimated insulin resistance values were decreased in HFD- or HS-fed CTRP1 TG mice compared with wild-type control mice. In this context, CTRP1 stimulated glucose uptake through the glucose transporter GLUT4 translocation to the plasma membrane and also increased glucose consumption by stimulating glycolysis. To analyze the roles of CTRP1 in lipid metabolism, acetyl-CoA carboxylase (ACC) and hormone-sensitive lipase levels were determined in CTRP1 TG mice, and the effect of CTRP1 on fatty acid oxidation was assessed in C2C12 myotubes. CTRP1 was found to inhibit ACC by phosphorylation and to stimulate fatty acid oxidation in C2C12 myotubes. Taken together, CTRP1 performs active catabolic roles in vivo. Therefore, CTRP1 seems to perform a defensive function against nutritional challenges.

Pancreatic cancer induced by in vivo electroporation-enhanced sleeping beauty transposon gene delivery system in mouse.

Objective The aim of this study was to establish a pancreatic tumor model of mouse using the electroporation-enhanced Sleeping Beauty (SB) transposon system. Methods The SB transposon system was used in conjunction with electroporation to deliver oncogenes, c-Myc and HRAS, and shRNA against p53 into the mouse pancreas to induce tumors. Oncogenes (c-Myc and HRAS) and shRNA against p53 gene were directly injected into the pancreas of the mouse along with in vivo electroporation applied on the injection site. The tumors were identified grossly and confirmed using animal positron emission tomographic imaging. The tumors were then characterized using histological and immunohistochemical techniques. The expression of the targeted genes (c-Myc, HRAS, and p53) was analyzed by a real-time quantitative polymerase chain reaction. Results Pancreatic tumors were successfully induced. The tumor phenotype was a sarcomatoid carcinoma, which was verified through immunohistochemistry. Some cysts or duct-like structures suggested to be metaplastic acinar cells were visible in the induced tumor. Conclusions The SB transposon enhanced with electroporation can readily generate pancreatic tumors in the mice, and thus, this model serves as a valuable resource for the mouse models of pancreatic cancer.

CKD‐501, a novel selective PPARγ agonist, shows no carcinogenic potential in ICR mice following oral administration for 104 weeks

CKD‐501 is a peroxisome proliferator‐activated receptor gamma (PPARγ) agonist that is effective for the treatment of diabetes. However, its carcinogenic potential remains controversial. The current carcinogenicity study was conducted over a period of 104 weeks in ICR mice. Three groups, each consisting of 60 male and 60 female mice, received oral CKD‐501 dosages of 0.2, 1.0 or 6.0 mgu2009kg−1day–1. The mortality rates of the male control, 0.2, 1.0 and 6.0 mg kg–1u2009day–1 treated groups were 60%, 68%, 58% and 67%, respectively and 57%, 68% and 67% in the female control, 0.2 and 1.0u2009mgu2009kg−1u2009day–1 treated groups. It was 67% in the female 6.0u2009mgu2009kg−1u2009day–1 treated group, which was terminated at week 98 due to its increased mortality rate. No significant treatment‐related effects were observed on the survival rates, with the exception of females in the 6.0u2009mgu2009kg−1u2009day–1 group. Body weights increased in females receiving 1.0 and 6.0u2009mgu2009kg−1u2009day–1 due to the class effects of the PPARγ agonist. Differences were not found in hematology parameters between the CKD‐501‐treated groups and their corresponding controls, but the histopathological evidence did not reveal any findings attributed to CKD‐501. Treated animals exhibited non‐neoplastic findings (adipocyte proliferation, bone marrow hypoplasia cardiomyopathy), but all of these were expected changes for this class of compound. There were no treatment‐related neoplastic changes in this study. The results of this study therefore demonstrate a lack of carcinogenicity following oral administration of CKD‐501 to ICR mice for 104u2009weeks. Copyright

An iatrogenic dermatosis with ulceration

A 36-year-old woman presented with a 1-year history of denuded nodules on the perianal area. She complained of skin laxity in the axilla, groin and abdomen of 7 years’ duration, and she had multiple, yellowish, 2–3 mm sized papules on her neck, giving a plucked chicken appearance (Fig. 1). She had been on longterm penicillamine therapy at a dose of 1 g daily since the age of 10 years for treatment of Wilson’s disease. Skin examination demonstrated several denuded nodules with marginal induration on the perianal area (Fig. 2).

Development of a Mouse Model of Prostate Cancer Using the Sleeping Beauty Transposon and Electroporation

The Sleeping Beauty (SB) transposon system is non-viral and uses insertional mutagenesis, resulting in the permanent expression of transferred genes. Although the SB transposon is a useful method for establishing a mouse tumor model, there has been difficulty in using this method to generate tumors in the prostate. In the present study, electroporation was used to enhance the transfection efficiency of the SB transposon. To generate tumors, three constructs (a c-Myc expression cassette, a HRAS (HRas proto-oncogene, GTPase) expression cassette and a shRNA against p53) contained within the SB transposon plasmids were directly injected into the prostate. Electroporation was conducted on the injection site after the injection of the DNA plasmid. Following the tumorigenesis, the tumors were monitored by animal PET imaging and identified by gross observation. After this, the tumors were characterized by using histological and immunohistochemical techniques. The expression of the targeted genes was analyzed by Real-Time qRT-PCR. All mice subjected to the injection were found to have prostate tumors, which was supported by PSA immunohistochemistry. To our knowledge, this is the first demonstration of tumor induction in the mouse prostate using the electroporation-enhanced SB transposon system in combination with c-Myc, HRAS and p53. This model serves as a valuable resource for the future development of SB-induced mouse models of cancer.

Evaluation of Circulating MicroRNA Biomarkers in the Acute Pancreatic Injury Dog Model

This study aimed to evaluate the usefulness of four microRNAs (miRNAs) in an acute pancreatic injury dog model. Acute pancreatitis was induced by infusion of cerulein for 2 h (7.5 μg/kg/h). The levels of well-known miRNAs, microRNA-216a (miR-216a) and microRNA-375 (miR-375), and new candidates microRNA-551b (miR-551b), and microRNA-7 (miR-7), were measured at 0, 0.5, 1, 2, 6, 12, and 24 h with serum amylase and lipase, and histopathological examination was performed. Among the four miRNAs, miR-216a and miR-375, and serum enzymes were significantly increased by cerulein treatment. The expression levels of miRNAs and serum enzymes peaked at 2–6 h with a similar pattern; however, the overall increases in miR-216a and miR-375 levels were much higher than those of the serum enzyme biomarkers. Increased levels of miR-216a and miR-375 were most highly correlated to the degree of individual histopathological injuries of the pancreas, and showed much greater dynamic response than serum enzyme biomarkers. Twenty-four-hour time-course analysis in this study revealed time-dependent changes of miRNA expression levels, from initial increase to decrease by predose level in acute pancreatitis. Our findings demonstrate that, in dogs, miR-216a and miR-375 have the potential to sensitively detect pancreatitis and reflect well the degree of pancreatic injury, whereas miR-551b and miR-7 do not.

Usefulness of optical coherence tomography to detect central serous chorioretinopathy in monkeys

Many systemic drugs can induce ocular toxicity and several ocular side‐effects have been identified in clinical studies. However, it is difficult to detect ocular toxicity in preclinical studies because of the lack of appropriate evaluation methods. Optical coherence tomography (OCT) is useful because it can provide real‐time images throughout a study period, whereas histopathology only provides images of sacrificed animals. Using OCT alongside histopathology, attempts were made to find effective approaches for screening of drug‐induced ocular toxicity in monkeys. Such approaches could be used in preclinical studies prior to human trials. Six male cynomolgus monkeys (Macaca fascicularis Raffles) were orally administered one of six candidate MAPK/ERK kinase (MEK) inhibitors. Central serous chorioretinopathy, a known side‐effect of such inhibitors, was identified in four monkeys by OCT. Artifacts generated during tissue processing meant that histopathology could not detect edematous changes. Thus, OCT is a useful tool to detect ocular toxicity which cannot be detected by histopathology in preclinical studies. Copyright