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1.
J Pers Med ; 14(4)2024 Mar 30.
Article in English | MEDLINE | ID: mdl-38672997

ABSTRACT

Hepatocellular carcinoma (HCC) is a common complication of chronic liver diseases and remains a relevant cause of cancer-related mortality worldwide. The global prevalence of metabolic dysfunction-associated steatotic liver disease (MASLD) as a risk factor for hepatocarcinogenesis is on the rise. Early detection of HCC has been crucial in improving the survival outcomes of patients with metabolic dysfunction-associated steatohepatitis (MASH), even in the absence of cirrhosis. Understanding how hepatocarcinogenesis develops in MASH is increasingly becoming a current research focus. Additive risk factors such as type 2 diabetes mellitus (T2DM), genetic polymorphisms, and intestinal microbiota may have specific impacts. Pathophysiological and epidemiological associations between MASH and HCC will be discussed in this review. We will additionally review the available tumor therapies concerning their efficacy in MASH-associated HCC treatment.

2.
Liver Int ; 44(1): 125-138, 2024 01.
Article in English | MEDLINE | ID: mdl-37872645

ABSTRACT

OBJECTIVE: Progressive hepatic fibrosis can be considered the final stage of chronic liver disease. Hepatic stellate cells (HSC) play a central role in liver fibrogenesis. Thyroid hormones (TH, e.g. thyroxine; T4 and triiodothyronine; T3) significantly affect development, growth, cell differentiation and metabolism through activation of TH receptor α and/or ß (TRα/ß). Here, we evaluated the influence of TH in hepatic fibrogenesis. DESIGN: Human liver tissue was obtained from explanted livers following transplantation. TRα-deficient (TRα-KO) and wild-type (WT) mice were fed a control or a profibrogenic methionine-choline deficient (MCD) diet. Liver tissue was assessed by qRT-PCR for fibrogenic gene expression. In vitro, HSC were treated with TGFß in the presence or absence of T3. HSC with stable TRα knockdown and TRα deficient mouse embryonic fibroblasts (MEF) were used to determine receptor-specific function. Activation of HSC and MEF was assessed using the wound healing assay, Western blotting, and qRT-PCR. RESULTS: TRα and TRß expression is downregulated in the liver during hepatic fibrogenesis in humans and mice. TRα represents the dominant isoform in HSC. In vitro, T3 blunted TGFß-induced expression of fibrogenic genes in HSC and abrogated wound healing by modulating TGFß signalling, which depended on TRα presence. In vivo, TRα-KO enhanced MCD diet-induced liver fibrogenesis. CONCLUSION: These observations indicate that TH action in non-parenchymal cells is highly relevant. The interaction of TRα with TH regulates the phenotype of HSC via the TGFß signalling pathway. Thus, the TH-TR axis may be a valuable target for future therapy of liver fibrosis.


Subject(s)
Fibroblasts , Hepatic Stellate Cells , Animals , Mice , Humans , Hepatic Stellate Cells/metabolism , Thyroid Hormones/metabolism , Thyroid Hormones/pharmacology , Thyroid Hormone Receptors alpha/genetics , Thyroid Hormone Receptors alpha/metabolism , Transforming Growth Factor beta
3.
Metabolites ; 12(2)2022 Jan 30.
Article in English | MEDLINE | ID: mdl-35208205

ABSTRACT

Celiac disease (CeD) is a chronic autoimmune disorder characterized by an intolerance to storage proteins of many grains. CeD is frequently associated with liver damage and steatosis. Bile acid (BA) signaling has been identified as an important mediator in gut-liver interaction and the pathogenesis of non-alcoholic fatty liver disease (NAFLD). Here, we aimed to analyze BA signaling and liver injury in CeD patients. Therefore, we analyzed data of 20 CeD patients on a gluten-free diet compared to 20 healthy controls (HC). We furthermore analyzed transaminase levels, markers of cell death, BA, and fatty acid metabolism. Hepatic steatosis was determined via transient elastography, by MRI and non-invasive scores. In CeD, we observed an increase of the apoptosis marker M30 and more hepatic steatosis as compared to HC. Fibroblast growth factor 19 (FGF19) was repressed in CeD, while low levels were associated with steatosis, especially in patients with high levels of anti-tissue transglutaminase antibodies (anti-tTG). When comparing anti-tTG-positive CeD patients to individuals without detectable anti-tTG levels, hepatic steatosis was accentuated. CeD patients with significant sonographic steatosis (defined by CAP ≥ 283 db/m) were exclusively anti-tTG-positive. In summary, our results suggest that even in CeD patients in clinical remission under gluten-free diet, alterations in gut-liver axis, especially BA signaling, might contribute to steatotic liver injury and should be further addressed in future studies and clinical practice.

4.
Liver Int ; 41(11): 2646-2658, 2021 11.
Article in English | MEDLINE | ID: mdl-34219348

ABSTRACT

BACKGROUND AND AIMS: An association between Crohn's disease (CD) and hepatic steatosis has been reported. However, the underlying mechanisms of steatosis progression in CD are not clear. Among the most effective CD treatments are agents that inhibit Tumor-Necrosis-Factor (TNF) activity, yet it is unclear why anti-TNFα agents would affect steatosis in CD. Recent studies suggest that microbiome can affect both, CD and steatosis pathogenesis. Therefore, we here analysed a potential relationship between anti-TNF treatment and hepatic steatosis in CD, focusing on the gut-liver axis. METHODS: This cross-sectional study evaluated patients with established CD, with and without anti-TNFα treatment, analysing serum markers of liver injury, measurement of transient elastography, controlled attenuation parameter (CAP) and MRI for fat detection. Changes in lipid and metabolic profiles were assessed by serum and stool lipidomics and metabolimics. Additionally, we analysed gut microbiota composition and mediators of bile acid (BA) signalling via stool and serum analysis. RESULTS: Patients on anti-TNFα treatment had less hepatic steatosis as assessed by CAP and MRI. Serum FGF19 levels were significantly higher in patients on anti-TNFα therapy and associate with reduced steatosis and increased bowel motility. Neutral lipids including triglycerides were reduced in the serum of patients on anti-TNF treatment. Bacteria involved in BA metabolism and FGF19 regulation, including Firmicutes, showed group-specific alterations with low levels in patients without anti-TNFα treatment. Low abundance of Firmicutes was associated with higher triglyceride levels. CONCLUSIONS: Anti-TNFα treatment is associated with reduced steatosis, lower triglyceride levels, alterations in FXR-signalling (eg FGF19) and microbiota composition in CD.


Subject(s)
Crohn Disease , Fatty Liver , Crohn Disease/drug therapy , Cross-Sectional Studies , Hormones , Humans , Tumor Necrosis Factor Inhibitors
5.
Am J Physiol Gastrointest Liver Physiol ; 320(6): G1044-G1053, 2021 06 01.
Article in English | MEDLINE | ID: mdl-33908271

ABSTRACT

Myosin 1c (Myo1c) is an unconventional myosin that modulates signaling pathways involved in tissue injury and repair. In this study, we observed that Myo1c expression is significantly upregulated in human chronic liver disease such as nonalcoholic steatohepatitis (NASH) and in animal models of liver fibrosis. High throughput data from the GEO-database identified similar Myo1c upregulation in mice and human liver fibrosis. Notably, transforming growth factor-ß1 (TGF-ß1) stimulation to hepatic stellate cells (HSCs), the liver pericyte and key cell type responsible for the deposition of extracellular matrix, upregulates Myo1c expression, whereas genetic depletion or pharmacological inhibition of Myo1c blunted TGF-ß-induced fibrogenic responses, resulting in repression of α-smooth muscle actin (α-SMA) and collagen type I α 1 chain (Col1α1) mRNA. Myo1c deletion also decreased fibrogenic processes such as cell proliferation, wound healing response, and contractility when compared with vehicle-treated HSCs. Importantly, phosphorylation of mothers against decapentaplegic homolog 2 (SMAD2) and mothers against decapentaplegic homolog 3 (SMAD3) were significantly blunted upon Myo1c inhibition in GRX cells as well as Myo1c knockout (Myo1c-KO) mouse embryonic fibroblasts (MEFs) upon TGF-ß stimulation. Using the genetic Myo1c-KO mice, we confirmed that Myo1c is critical for fibrogenesis, as Myo1c-KO mice were resistant to carbon tetrachloride (CCl4)-induced liver fibrosis. Histological and immunostaining analysis of liver sections showed that deposition of collagen fibers and α-SMA expression were significantly reduced in Myo1c-KO mice upon liver injury. Collectively, these results demonstrate that Myo1c mediates hepatic fibrogenesis by modulating TGF-ß signaling and suggest that inhibiting this process may have clinical application in treating liver fibrosis.NEW & NOTEWORTHY The incidences of liver fibrosis are growing at a rapid pace and have become one of the leading causes of end-stage liver disease. Although TGF-ß1 is known to play a prominent role in transforming cells to produce excessive extracellular matrix that lead to hepatic fibrosis, the therapies targeting TGF-ß1 have achieved very limited clinical impact. This study highlights motor protein myosin-1c-mediated mechanisms that serve as novel regulators of TGF-ß1 signaling and fibrosis.


Subject(s)
Fibroblasts/metabolism , Liver Cirrhosis/metabolism , Liver/metabolism , Myosin Type I/metabolism , Animals , Collagen Type I, alpha 1 Chain , Fibroblasts/pathology , Hepatic Stellate Cells/metabolism , Hepatic Stellate Cells/pathology , Liver/pathology , Liver Cirrhosis/genetics , Liver Cirrhosis/pathology , Mice , Myosin Type I/genetics , Phosphorylation , Signal Transduction/physiology , Transforming Growth Factor beta/metabolism
6.
Proc Natl Acad Sci U S A ; 117(21): 11432-11443, 2020 05 26.
Article in English | MEDLINE | ID: mdl-32381732

ABSTRACT

The structure and mechanics of many connective tissues are dictated by a collagen-rich extracellular matrix (ECM), where collagen fibers provide topological cues that direct cell migration. However, comparatively little is known about how cells navigate the hyaluronic acid (HA)-rich, nanoporous ECM of the brain, a problem with fundamental implications for development, inflammation, and tumor invasion. Here, we demonstrate that glioblastoma cells adhere to and invade HA-rich matrix using microtentacles (McTNs), which extend tens of micrometers from the cell body and are distinct from filopodia. We observe these structures in continuous culture models and primary patient-derived tumor cells, as well as in synthetic HA matrix and organotypic brain slices. High-magnification and superresolution imaging reveals McTNs are dynamic, CD44-coated tubular protrusions containing microtubules and actin filaments, which respectively drive McTN extension and retraction. Molecular mechanistic studies reveal that McTNs are stabilized by an interplay between microtubule-driven protrusion, actomyosin-driven retraction, and CD44-mediated adhesion, where adhesive and cytoskeletal components are mechanistically coupled by an IQGAP1-CLIP170 complex. McTNs represent a previously unappreciated mechanism through which cells engage nanoporous HA matrix and may represent an important molecular target in physiology and disease.


Subject(s)
Glioblastoma/pathology , Hyaluronan Receptors/metabolism , Actins/metabolism , Animals , Brain/cytology , Brain/metabolism , Cell Adhesion , Cell Line, Tumor , Cell Movement , Extracellular Matrix/metabolism , Extracellular Matrix/pathology , Female , Gene Knockout Techniques , Glioblastoma/metabolism , Humans , Hyaluronic Acid/metabolism , Mice , Microtubule-Associated Proteins/metabolism , Microtubules/metabolism , Myosins/metabolism , Neoplasm Proteins/metabolism , Oligopeptides/metabolism , Organ Culture Techniques , ras GTPase-Activating Proteins/genetics , ras GTPase-Activating Proteins/metabolism
7.
Dig Dis Sci ; 64(8): 2351-2358, 2019 08.
Article in English | MEDLINE | ID: mdl-31155687

ABSTRACT

BACKGROUND: Thyroid hormone is critical for tissue-organ development, growth, differentiation, and metabolism. In murine models of advanced nonalcoholic steatohepatitis (NASH), the administration of T3 reduced liver triglyceride, repressed liver inflammation, and attenuated injury. In recent studies of patients with NASH, hypothyroidism was noted to be associated with more advanced NASH. These findings suggest that thyroid hormone function might be a modulator of nonalcoholic fatty liver disease (NAFLD) outcomes. AIMS: Herein, we evaluated the correlation between plasma TSH/free T3 (fT3)/free T4 (fT4) levels and (non-invasive) surrogate markers of NAFLD fibrosis. METHODS: We performed a retrospective analysis of 144 patients who were seen in our NASH outpatient clinic between 2015 and 2017. Each patient underwent a standard anthropometric assessment, laboratory and clinical evaluations, and liver stiffness measurements by transient elastography (Fibroscan). Univariate analysis and multivariate linear and logistic regression analysis were used to identify factors independently associated with NASH and advanced fibrosis. RESULTS: Low fT3 values but not TSH and fT4 were associated with higher liver stiffness and higher NAFLD fibrosis score, respectively. fT3 and TSH values correlated significantly with indices of liver disease including INR, albumin, ALT, AST, bilirubin, and platelets. In multivariate analyses, a low fT3 was independently associated with high NFS scores (OR 0.169, CI 0.05-0.54, p = 0.003) and was also associated with high liver stiffness readings (OR 0.326, CI 0.135-0.785, p = 0.001). CONCLUSION: A low-normal thyroid hormone function is predictive of NASH and advanced fibrosis and may have a pathogenic role in modulating NAFLD outcomes.


Subject(s)
Liver Cirrhosis/etiology , Non-alcoholic Fatty Liver Disease/complications , Triiodothyronine/blood , Biomarkers/blood , Down-Regulation , Female , Humans , Liver Cirrhosis/blood , Liver Cirrhosis/diagnostic imaging , Male , Middle Aged , Non-alcoholic Fatty Liver Disease/blood , Non-alcoholic Fatty Liver Disease/diagnostic imaging , Prognosis , Retrospective Studies , Risk Assessment , Risk Factors , Thyrotropin/blood , Thyroxine/blood
8.
Nat Rev Mater ; 4(10): 651-668, 2019 Oct.
Article in English | MEDLINE | ID: mdl-32647587

ABSTRACT

Glioblastoma (GBM) is the most aggressive and common form of primary brain cancer. Several decades of research have provided great insight into GBM progression; however, the prognosis remains poor with a median patient survival time of ~ 15 months. The tumour microenvironment (TME) of GBM plays a crucial role in mediating tumour progression and thus is being explored as a therapeutic target. Progress in the development of treatments targeting the TME is currently limited by a lack of model systems that can accurately recreate the distinct extracellular matrix composition and anatomic features of the brain, such as the blood-brain barrier and axonal tracts. Biomaterials can be applied to develop synthetic models of the GBM TME to mimic physiological and pathophysiological features of the brain, including cellular and ECM composition, mechanical properties, and topography. In this Review, we summarize key features of the GBM microenvironment and discuss different strategies for the engineering of GBM TME models, including 2D and 3D models featuring chemical and mechanical gradients, interfaces and fluid flow. Finally, we highlight the potential of engineered TME models as platforms for mechanistic discovery and drug screening as well as preclinical testing and precision medicine.

9.
Am J Med Sci ; 355(2): 183-190, 2018 02.
Article in English | MEDLINE | ID: mdl-29406047

ABSTRACT

BACKGROUND: Although excess iron induces oxidative stress in the liver, it is unclear whether it directly activates the hepatic stellate cells (HSC). MATERIALS AND METHODS: We evaluated the effects of excess iron on fibrogenesis and transforming growth factor beta (TGF-ß) signaling in murine HSC. Cells were treated with holotransferrin (0.005-5g/L) for 24 hours, with or without the iron chelator deferoxamine (10µM). Gene expressions (α-SMA, Col1-α1, Serpine-1, TGF-ß, Hif1-α, Tfrc and Slc40a1) were analyzed by quantitative real time-polymerase chain reaction, whereas TfR1, ferroportin, ferritin, vimentin, collagen, TGF-ß RII and phospho-Smad2 proteins were evaluated by immunofluorescence, Western blot and enzyme-linked immunosorbent assay. RESULTS: HSC expressed the iron-uptake protein transferrin receptor 1 (TfR1) and the iron-export protein ferroportin. Holotransferrin upregulated TfR1 expression by 1.8-fold (P < 0.03) and ferritin accumulation (iron storage) by 2-fold (P < 0.01), and activated HSC with 2-fold elevations (P < 0.03) in α-SMA messenger RNA and collagen secretion, and a 1.6-fold increase (P < 0.01) in vimentin protein. Moreover, holotransferrin activated the TGF-ß pathway with TGF-ß messenger RNA elevated 1.6-fold (P = 0.05), and protein levels of TGF-ß RII and phospho-Smad2 increased by 1.8-fold (P < 0.01) and 1.6-fold (P < 0.01), respectively. In contrast, iron chelation decreased ferritin levels by 30% (P < 0.03), inhibited collagen secretion by 60% (P < 0.01), repressed fibrogenic genes α-SMA (0.2-fold; P < 0.05) and TGF-ß (0.4-fold; P < 0.01) and reduced levels of TGF-ß RII and phospho-Smad2 proteins. CONCLUSIONS: HSC express iron-transport proteins. Holotransferrin (iron) activates HSC fibrogenesis and the TGF-ß pathway, whereas iron depletion by chelation reverses this, suggesting that this could be a useful adjunct therapy for patients with fibrosis. Further studies in primary human HSC and animal models are necessary to confirm this.


Subject(s)
Gene Expression Regulation , Hepatic Stellate Cells/metabolism , Iron/metabolism , Liver Cirrhosis/metabolism , Signal Transduction , Transforming Growth Factor beta/metabolism , Animals , Cell Line , Ferritins/biosynthesis , Hepatic Stellate Cells/pathology , Liver Cirrhosis/pathology , Mice , Protein Serine-Threonine Kinases/biosynthesis , RNA, Messenger/biosynthesis , Receptor, Transforming Growth Factor-beta Type II , Receptors, Transferrin/biosynthesis , Receptors, Transforming Growth Factor beta/biosynthesis , Smad2 Protein/metabolism
10.
Data Brief ; 14: 538-542, 2017 Oct.
Article in English | MEDLINE | ID: mdl-28856185

ABSTRACT

This data contains information related to the research article entitled "Osteopontin splice variants and polymorphisms in Cancer Progression and Prognosis" [1]. Here, we describe an in silico analysis of transcription factors that could have altered binding to their DNA target sequence as a result of SNPs in the osteopontin gene promoter. We concentrated on SNPs associated with cancer risk and development. The analysis was performed with PROMO v3.0.2 software which incorporates TRANSFACT v6.4 of. We also present a figure depicting the putative transcription factor binding according to genotype.

11.
Biochim Biophys Acta Rev Cancer ; 1868(1): 93-108.A, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28254527

ABSTRACT

Osteopontin (OPN) is an extracellular matrix protein that is overexpressed in various cancers and promotes oncogenic features including cell proliferation, survival, migration, and angiogenesis, among others. OPN can participate in the regulation of the tumor microenvironment, affecting both cancer and neighboring cells. Here, we review the roles of OPN splice variants (a, b, c) in cancer development, progression, and prognosis, and also discuss the identities of isoforms 4 and 5. We also discussed how single-nucleotide polymorphisms (SNPs) of the OPN gene are an additional factor influencing the level of OPN in individuals, modulating the risks of cancer development and outcome.


Subject(s)
Neoplasms/genetics , Neoplasms/pathology , Osteopontin/genetics , Polymorphism, Genetic/genetics , RNA Splicing/genetics , Amino Acid Sequence , Base Sequence , Disease Progression , Humans , Prognosis
12.
Biochim Biophys Acta ; 1862(1): 135-44, 2016 01.
Article in English | MEDLINE | ID: mdl-26529285

ABSTRACT

INTRODUCTION: Liver fibrosis develops when hepatic stellate cells (HSC) are activated into collagen-producing myofibroblasts. In non-alcoholic steatohepatitis (NASH), the adipokine leptin is upregulated, and promotes liver fibrosis by directly activating HSC via the hedgehog pathway. We reported that hedgehog-regulated osteopontin (OPN) plays a key role in promoting liver fibrosis. Herein, we evaluated if OPN mediates leptin-profibrogenic effects in NASH. METHODS: Leptin-deficient (ob/ob) and wild-type (WT) mice were fed control or methionine-choline deficient (MCD) diet. Liver tissues were assessed by Sirius-red, OPN and αSMA IHC, and qRT-PCR for fibrogenic genes. In vitro, HSC with stable OPN (or control) knockdown were treated with recombinant (r)leptin and OPN-neutralizing or sham-aptamers. HSC response to OPN loss was assessed by wound healing assay. OPN-aptamers were also added to precision-cut liver slices (PCLS), and administered to MCD-fed WT (leptin-intact) mice to determine if OPN neutralization abrogated fibrogenesis. RESULTS: MCD-fed WT mice developed NASH-fibrosis, upregulated OPN, and accumulated αSMA+ cells. Conversely, MCD-fed ob/ob mice developed less fibrosis and accumulated fewer αSMA+ and OPN+ cells. In vitro, leptin-treated HSC upregulated OPN, αSMA, collagen 1α1 and TGFß mRNA by nearly 3-fold, but this effect was blunted by OPN loss. Inhibition of PI3K and transduction of dominant negative-Akt abrogated leptin-mediated OPN induction, while constitutive active-Akt upregulated OPN. Finally, OPN neutralization reduced leptin-mediated fibrogenesis in both PCLS and MCD-fed mice. CONCLUSION: OPN overexpression in NASH enhances leptin-mediated fibrogenesis via PI3K/Akt. OPN neutralization significantly reduces NASH fibrosis, reinforcing the potential utility of targeting OPN in the treatment of patients with advanced NASH.


Subject(s)
Leptin/metabolism , Liver Cirrhosis/metabolism , Liver/pathology , Non-alcoholic Fatty Liver Disease/metabolism , Osteopontin/metabolism , Animals , Cell Line , Cells, Cultured , Gene Deletion , Hepatocytes/metabolism , Hepatocytes/pathology , Leptin/genetics , Liver/metabolism , Liver Cirrhosis/genetics , Liver Cirrhosis/pathology , Male , Mice, Inbred C57BL , Non-alcoholic Fatty Liver Disease/genetics , Non-alcoholic Fatty Liver Disease/pathology , Osteopontin/genetics , Phosphatidylinositol 3-Kinases/metabolism , Proto-Oncogene Proteins c-akt/metabolism , Rats, Sprague-Dawley , Signal Transduction , Up-Regulation
13.
Cell Mol Biol Lett ; 20(4): 626-46, 2015 Dec.
Article in English | MEDLINE | ID: mdl-26274783

ABSTRACT

Extensive re-organisation of the actin cytoskeleton and changes in the expression of its binding proteins is a characteristic feature of cancer cells. Previously we have shown that the tropomyosin isoform Tpm3.1, an integral component of the actin cytoskeleton in tumor cells, is required for tumor cell survival. Our objective was to determine whether cancer cells devoid of Tpm3.1 would evade the tumorgenic effects induced by H-Ras transformation. The tropomyosin isoform (Tpm) expression profile of a range of cancer cell lines (21) demonstrates that Tpm3.1 is one of the most broadly expressed Tpm isoform. Consequently, the contribution of Tpm3.1 to the transformation process was functionally evaluated. Primary embryonic fibroblasts isolated from wild type (WT) and Tpm3.1 knockout (KO) mice were transduced with retroviral vectors expressing SV40 large T antigen and an oncogenic allele of the H-Ras gene, H-RasV12, to generate immortalized and transformed WT and KO MEFs respectively. We show that Tpm3.1 is required for growth factor-independent proliferation in the SV40 large T antigen immortalized MEFs, but this requirement is overcome by H-Ras transformation. Consistent with those findings, we found that Tpm3.1 was not required for anchorage independent growth or growth of H-Ras-driven tumors in a mouse model. Finally, we show that pERK and Importin 7 protein interactions are significantly decreased in the SV40 large T antigen immortalized KO MEFs but not in the H-Ras transformed KO cells, relative to control MEFs. The data demonstrate that H-Ras transformation overrides a requirement for Tpm3.1 in growth factor-independent proliferation of immortalized MEFs. We propose that in the SV40 large T antigen immortalized MEFs, Tpm3.1 is partly responsible for the efficient interaction between pERK and Imp7 resulting in cell proliferation, but this is overidden by Ras transformation.


Subject(s)
Cell Transformation, Neoplastic/genetics , Gene Expression Regulation, Neoplastic , Genes, ras/genetics , Tropomyosin/genetics , Animals , Antigens, Polyomavirus Transforming/genetics , Cell Line, Tumor , Cell Proliferation , Cells, Cultured , Extracellular Signal-Regulated MAP Kinases/metabolism , Female , Fibroblasts/pathology , Humans , Karyopherins/genetics , Karyopherins/metabolism , Mice, Inbred BALB C , Mice, Inbred C57BL , Mice, Knockout , Protein Isoforms/genetics , Protein Isoforms/metabolism , Tropomyosin/metabolism
14.
Mol Biol Cell ; 26(13): 2475-90, 2015 Jul 01.
Article in English | MEDLINE | ID: mdl-25971798

ABSTRACT

ERK-regulated cell proliferation requires multiple phosphorylation events catalyzed first by MEK and then by casein kinase 2 (CK2), followed by interaction with importin7 and subsequent nuclear translocation of pERK. We report that genetic manipulation of a core component of the actin filaments of cancer cells, the tropomyosin Tm5NM1, regulates the proliferation of normal cells both in vitro and in vivo. Mouse embryo fibroblasts (MEFs) lacking Tm5NM1, which have reduced proliferative capacity, are insensitive to inhibition of ERK by peptide and small-molecule inhibitors, indicating that ERK is unable to regulate proliferation of these knockout (KO) cells. Treatment of wild-type MEFs with a CK2 inhibitor to block phosphorylation of the nuclear translocation signal in pERK resulted in greatly decreased cell proliferation and a significant reduction in the nuclear translocation of pERK. In contrast, Tm5NM1 KO MEFs, which show reduced nuclear translocation of pERK, were unaffected by inhibition of CK2. This suggested that it is nuclear translocation of CK2-phosphorylated pERK that regulates cell proliferation and this capacity is absent in Tm5NM1 KO cells. Proximity ligation assays confirmed a growth factor-stimulated interaction of pERK with Tm5NM1 and that the interaction of pERK with importin7 is greatly reduced in the Tm5NM1 KO cells.


Subject(s)
Actin Cytoskeleton/physiology , MAP Kinase Signaling System/physiology , Tropomyosin/physiology , Actin Cytoskeleton/genetics , Actin Cytoskeleton/metabolism , Active Transport, Cell Nucleus , Animals , Casein Kinase II/metabolism , Cell Line, Tumor , Cell Proliferation/physiology , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Mice, Transgenic , Mitogen-Activated Protein Kinase Kinases/metabolism , Phosphorylation , Tropomyosin/genetics , Tropomyosin/metabolism
15.
Clin Gastroenterol Hepatol ; 13(10): 1836-1842.e2; quiz e157-8, 2015 Oct.
Article in English | MEDLINE | ID: mdl-25912835

ABSTRACT

BACKGROUND & AIMS: In Western countries, infection with the hepatitis E virus (HEV) is considered to be rare and imported from endemic regions. However, the prevalence of HEV infection has increased among adults in central Europe. HEV infection can cause acute liver failure (ALF), but there have been only a few confirmed cases of HEV-associated ALF in Europe. We investigated the number of cases of indeterminate ALF associated with HEV infection. METHODS: We performed a retrospective analysis of 80 patients diagnosed with ALF or acute hepatitis at the University Hospital Essen in Germany from November 2006 through December 2013. Clinical data were collected from the hospital databases; archived sera were tested for IgG and IgM against HEV, as well as HEV RNA. RESULTS: Sera from 12 patients (15%) tested positive for IgG against HEV IgG; 7 of these samples did not test positive for HEV IgM or HEV RNA. Sera from 64 patients (80%) did not test positive for IgG or IgM against HEV or HEV RNA. Sera from 8 patients (10%) tested positive for HEV RNA (only 4 of these were positive for HEV IgG) and had clinical findings to support acute HEV infection. CONCLUSIONS: In a hospital in Germany, approximately 10% to 15% of patients with ALF had evidence for HEV infection. Serologic tests for IgG against HEV are insufficient to identify or exclude HEV infection; tests for HEV RNA also should be performed on patients with ALF of ambiguous etiology.


Subject(s)
Hepatitis E/complications , Liver Failure, Acute/epidemiology , Liver Failure, Acute/etiology , Adult , Europe/epidemiology , Female , Germany/epidemiology , Hepatitis Antibodies/blood , Hepatitis E virus/genetics , Hepatitis E virus/immunology , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Male , Middle Aged , Prevalence , RNA, Viral/blood , Retrospective Studies
17.
Front Physiol ; 4: 258, 2013 Sep 26.
Article in English | MEDLINE | ID: mdl-24133449

ABSTRACT

Acute liver failure (ALF) results from the acute and rapid loss of hepatocyte function and frequently exhibits a fulminant course, characterized by high mortality in the absence of immediate state-of-the-art intensive care and/or emergency liver transplantation (ELT). The role of hepatocyte-mediated liver regeneration during acute and chronic liver injury has been extensively investigated, and recent studies suggest that hepatocytes are not exclusively responsible for the regeneration of the injured liver during fulminant liver injury. Liver progenitor cells (LPC) (or resident liver stem cells) are quiescent in the healthy liver, but may be activated under conditions where the regenerative capacity of mature hepatocytes is severely impaired. This review aims to provide an overview of the role of the LPC population during ALF, and the role of putative cytokines, growth factors, mitogens, and hormones in the LPC response. We will highlight the potential interaction among cellular compartments during ALF, and discuss the possible prognostic value of the LPC response on ALF outcomes.

20.
Nephrol Dial Transplant ; 22(8): 2175-82, 2007 Aug.
Article in English | MEDLINE | ID: mdl-17550925

ABSTRACT

BACKGROUND: In this study we tested the hypothesis that sirolimus (a target of rapamycin inhibitor that attenuates intrinsic renal and immune cell proliferation) reduces glomerular hypertrophy and tubular epithelial cell (TEC) proliferation, and attenuates the progression of renal scarring and dysfunction, in a non-immune initiated model of focal segmental glomerulosclerosis (FSGS). METHODS: Adult male Wistar rats with adriamycin nephropathy (AN) were stratified into two groups, according to proteinuria on day 12, and received either vehicle (dimethylsulphoxide) or sirolimus (0.1 mg/kg) by daily subcutaneous injection, from day 14 until day 49 (n = 8 each). Control animals were also examined (n = 3 each). RESULTS: Sirolimus did not affect the progression of proteinuria, renal dysfunction, hypercholesterolaemia, body weight or alter intraluminal cast formation in AN. Sirolimus prevented the increase in kidney enlargement in AN, and attenuated glomerular capillary tuft expansion, glomerulosclerosis and periglomerular myofibroblast accumulation. In the tubulointerstitium, sirolimus attenuated tubular dilatation, TEC proliferation and interstitial fibrosis. This was accompanied by a reduction in renal cortical TGF-beta1, but peritubular myofibroblast accumulation and renal inflammation (glomerular and interstitial ED-1 and CD3-positive cell accumulation), were unaffected. CONCLUSION: The anti-renotrophic properties of sirolimus were correlated with a reduction in renal scarring in AN. These data suggest that sirolimus has renoprotective effects when administered during the early stages of an FSGS pattern of chronic renal injury.


Subject(s)
Glomerulosclerosis, Focal Segmental/drug therapy , Kidney Diseases/drug therapy , Kidney/drug effects , Sirolimus/pharmacology , Animals , Antibiotics, Antineoplastic/pharmacology , Body Weight , Cell Proliferation , Disease Progression , Doxorubicin/toxicity , Humans , Kidney Diseases/chemically induced , Male , Nephrotic Syndrome/pathology , Rats , Rats, Wistar
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