Exacerbation of non-steroidal anti-inflammatory drug-induced enteropathy in C-C chemokine receptor type 7-deficient mice.

BACKGROUND AND AIM: Non-steroidal anti-inflammatory drugs (NSAIDs) induce intestinal enteropathy and the pathophysiology is related to immune-mediated mechanisms. We aimed to investigate the role of C-C chemokine receptor type 7 (CCR7) which regulates immune cell migration in NSAID-induced enteropathy. METHODS: Injury of the small intestine was evaluated 24 h after the subcutaneous injection of indomethacin in CCR7-deficient (Ccr7-/- ) and wild-type (WT) mice. The cellular profile and cytokine production in intestinal cells were analyzed. Indomethacin-induced enteropathy was evaluated in mice adoptively transferred with CD103+ dendritic cells (DCs) from Ccr7-/- or WT mice. RESULTS: Indomethacin induced more severe intestinal injury in Ccr7-/- mice than in WT mice. The major inflammatory cytokines were not increased and the proportion of regulatory T cells following indomethacin injection was not decreased in Ccr7-/- mice compared with WT mice. The expression of interleukin (IL)-22 binding protein (IL-22BP), which inhibits IL-22 activity, was significantly higher in CD103+ DCs from Ccr7-/- mice than those from WT mice. Mice adoptively transferred with CD103+ DCs isolated from Ccr7-/- mice exhibited more severe intestinal injury following indomethacin injection compared with those adoptively transferred with CD103+ DCs of WT mice. Ccr7-/- mice injected with indomethacin showed a significant reduction in regenerating islet-derived 1 (Reg1) mRNA expression, which is regulated by IL-22, in intestinal epithelial cells. CONCLUSIONS: C-C chemokine receptor type 7 deficiency exacerbated NSAID-induced enteropathy in association with an altered phenotype of CD103+ DCs that produces IL-22BP. CCR7 contributes to protect the small intestine from NSAID-induced mucosal injury.

[A case of eosinophilic gastroenteritis caused after the use of Seprafilm®].

Eosinophilic gastroenteritis is a fairly uncommon condition. It has been suggested that allergic reactions may have played a role in the development of this illness. The case of a 66-year-old woman who had a total hysterectomy due to a right ovarian tumor is described here. At this operation, a sodium hyaluronate carboxymethylcellulose bioresorbable membrane (Seprafilm®) was used. She was admitted to our hospital 47 days after the operation with abdominal pain. Laboratory data indicated elevated WBC (29450/µl) and eosinophilia (69.2%), and CT scan showed thickening of intestinal wall and ascites around there. Ascites cytology showed a significant increase of eosinophils (94.0%). She began taking oral steroids after being diagnosed with eosinophilic gastroenteritis, and her symptoms improved quickly. Despite the fact that Seprafilm® was thought to be a reliable and safe tool, it was suggested that a foreign body reaction to Seprafilm® could lead to eosinophilic gastroenteritis.

Gab1 in livers with persistent hepatocyte apoptosis has an antiapoptotic effect and reduces chronic liver injury, fibrosis, and tumorigenesis.

Grb2-associated binder 1 (Gab1) is an adaptor protein that is important for intracellular signal transduction by receptor tyrosine kinases that are receptors for various growth factors and plays an important role in rapid liver regeneration after partial hepatectomy and during acute hepatitis. On the other hand, mild liver regeneration is induced in livers of individuals with chronic hepatitis, where hepatocyte apoptosis is persistent; however, the impact of Gab1 on such livers remains unclear. We examined the role of Gab1 in chronic hepatitis. Gab1 knockdown enhanced the decrease in cell viability and apoptosis induced by ABT-737, a Bcl-2/-xL/-w inhibitor, in BNL.CL2 cells, while cell viability and caspase activity were unchanged in the absence of ABT-737. ABT-737 treatment induced Gab1 cleavage to form p35-Gab1. p35-Gab1 was also detected in the livers of mice with hepatocyte-specific Mcl-1 knockout (KO), which causes persistent hepatocyte apoptosis. Gab1 deficiency exacerbated hepatocyte apoptosis in Mcl-1 KO mice with posttranscriptional downregulation of Bcl-XL. In BNL.CL2 cells treated with ABT-737, Gab1 knockdown posttranscriptionally suppressed Bcl-xL expression, and p35-Gab1 overexpression enhanced Bcl-xL expression. Gab1 deficiency in Mcl-1 KO mice activated STAT3 signaling in hepatocytes, increased hepatocyte proliferation, and increased the incidence of liver cancer with the exacerbation of liver fibrosis. In conclusion, Gab1 is cleaved in the presence of apoptotic stimuli and forms p35-Gab1 in hepatocytes. In chronic liver injury, the role of Gab1 in suppressing apoptosis and reducing liver damage, fibrosis, and tumorigenesis is more important than its role in liver regeneration.NEW & NOTEWORTHY Grb2-associated binder 1 (Gab1) is known to contribute to liver regeneration after acute liver injury. However, in chronic liver diseases, Gab1 plays a greater role in suppressing hepatocyte apoptosis than in liver regeneration, resulting in suppression of hepatocyte proliferation, liver fibrosis, and liver carcinogenesis.

Gab1 adaptor protein acts as a gatekeeper to balance hepatocyte death and proliferation during acetaminophen-induced liver injury in mice.

UNLABELLED: Acetaminophen (APAP) overdose is the leading cause of drug-induced acute liver failure. In APAP-induced acute liver failure, hepatocyte death and subsequent liver regeneration determines the prognosis of patients, making it necessary to identify suitable therapeutic targets based on detailed molecular mechanisms. Grb2-associated binder 1 (Gab1) adaptor protein plays a crucial role in transmitting signals from growth factor and cytokine receptors to downstream effectors. In this study, we hypothesized that Gab1 is involved in APAP-induced acute liver failure. Hepatocyte-specific Gab1 conditional knockout (Gab1CKO) and control mice were treated with 250 mg/kg of APAP. After APAP treatment, Gab1CKO mice had significantly higher mortality and elevated serum alanine aminotransferase levels compared to control mice. Gab1CKO mice had increased hepatocyte death and increased serum levels of high mobility group box 1, a marker of hepatocyte necrosis. In addition, Gab1CKO mice had reduced hepatocyte proliferation. The enhanced hepatotoxicity in Gab1CKO mice was associated with increased activation of stress-related c-Jun N-terminal kinase (JNK) and reduced activation of extracellular signal-regulated kinase and AKT. Furthermore, Gab1CKO mice showed enhanced mitochondrial translocation of JNK accompanied by an increase in the release of mitochondrial enzymes into the cytosol, which is indicative of increased mitochondrial dysfunction and subsequent nuclear DNA fragmentation. Finally, in vitro experiments showed that Gab1-deficient hepatocytes were more susceptible to APAP-induced mitochondrial dysfunction and cell death, suggesting that hepatocyte Gab1 is a direct target of APAP-induced hepatotoxicity. CONCLUSION: Our current data demonstrate that hepatocyte Gab1 plays a critical role in controlling the balance between hepatocyte death and compensatory hepatocyte proliferation during APAP-induced liver injury.

Increased expression of Forkhead box M1 transcription factor is associated with clinicopathological features and confers a poor prognosis in human hepatocellular carcinoma.

AIM: Forkhead Box M1 (FoxM1) is a proliferation-specific transcription factor. In this study, we aimed to elucidate the clinicopathological and prognostic values of FoxM1 expression in human hepatocellular carcinoma (HCC) and correlate FoxM1 expression with various etiologies of liver diseases. We also investigated its therapeutic value in HCC. METHODS: We investigated the expression of FoxM1 in tumor tissues and adjacent non-tumor tissues of 79 Japanese HCC patients by quantitative real-time reverse transcription-polymerase chain reaction analysis. Depletion by siRNA or specific inhibition by siomycin A were also used to investigate the effect of FoxM1 inhibition on stem-like features of human HCC cells. RESULTS: Quantitative real-time reverse transcription-polymerase chain reaction analysis showed that tumor tissues displayed an approximately 14-fold increase in FoxM1 expression compared with adjacent non-tumor tissues. Interestingly, the expression levels of FoxM1in tumor tissues did not depend on the etiology of liver disease. The expression of FoxM1 in tumor tissues was associated with serum α-fetoprotein level, maximum tumor size, histological grade, TNM staging, and portal involvement. Kaplan-Meier analysis indicated that the high FoxM1 expression (≥median) group had a poor prognosis compared with the low FoxM1 expression (

Forkhead Box M1 Transcription Factor Drives Liver Inflammation Linking to Hepatocarcinogenesis in Mice.

BACKGROUND & AIMS: Liver inflammation has been recognized as a hallmark of hepatocarcinogenesis. Although Forkhead Box M1 (FoxM1) is a well-defined oncogenic transcription factor that is overexpressed in hepatocellular carcinoma (HCC), its role in liver inflammation has never been explored. METHODS: We generated hepatocyte-specific FoxM1 conditional transgenic (TG) mice by using the Cre-loxP and Tetracycline (Tet)-on systems to induce FoxM1 expression in a hepatocyte-specific and time-dependent manner. RESULTS: After treatment of Tet-derivatives doxycycline (DOX) to induce FoxM1, TG mice exhibited spontaneous development of hepatocyte death with elevated serum alanine aminotransferase levels and hepatic infiltration of macrophages. The removal of DOX in TG mice completely removed this effect, suggesting that spontaneous inflammation in TG mice occurs in a hepatocyte FoxM1-dependent manner. In addition, liver inflammation in TG mice was associated with increased levels of hepatic and serum chemokine (C-C motif) ligand 2 (CCL2). In vitro transcriptional analysis confirmed that CCL2 is a direct target of FoxM1 in murine hepatocytes. After receiving FoxM1 induction since birth, all TG mice exhibited spontaneous HCC with liver fibrosis at 12 months of age. Hepatic expression of FoxM1 was significantly increased in liver injury models. Finally, pharmacologic inhibition of FoxM1 reduced liver inflammation in models of liver injury. CONCLUSIONS: Hepatocyte FoxM1 acts as a crucial regulator to orchestrate liver inflammation linking to hepatocarcinogenesis. Thus, hepatocyte FoxM1 may be a potential target not only for the treatment of liver injury but also for the prevention toward HCC.

Targeting the mevalonate pathway is a novel therapeutic approach to inhibit oncogenic FoxM1 transcription factor in human hepatocellular carcinoma.

Dysregulation of cell metabolism is a hallmark of cancer. The mevalonate pathway in lipid metabolism has been implicated as a potential target of cancer therapy for hepatocellular carcinoma (HCC). The role of the Forkhead Box M1 (FoxM1) transcription factor in HCC development has been well documented, however, its involvement in cancer metabolism of HCC has not been fully determined. Here, we hypothesized that FoxM1 is involved in the mevalonate pathway of cholesterol biosynthesis in HCC. Inhibition of the mevalonate pathway by statins, inhibitors of 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR), resulted in reduced expression of FoxM1 and increased cell death in human hepatoma cells. Re-exposure of mevalonate, a product of HMGCR, restored these effects. Likewise, knockdown of HMGCR reduced FoxM1 expression, indicating that FoxM1 expression was regulated by the mevalonate pathway in HCC. Mechanistically, protein geranylgeranylation was found to be responsible for FoxM1 expression and geranylgeranylated proteins, including RhoA, Rac1 or Cdc42, were shown to be involved in this process. In surgically resected human HCC tissues, the gene expression of FoxM1 had a positive correlation with that of the mevalonate pathway-related genes, such as HMGCR or sterol regulatory element-binding protein 2 (SREBP2). Furthermore, the gene expression of FoxM1 along with that of HMGCR or SREBP2 defined prognosis of HCC patients, suggesting the clinical significance of the mevalonate-FoxM1 pathway in human HCC. Our data indicate that FoxM1 links the mevalonate pathway to oncogenic signals in HCC. Thus, we propose a novel therapeutic approach to inhibit FoxM1 by targeting the mevalonate pathway for HCC.