bromochloroacetic-acid and Hepatitis--Alcoholic

Mallory bodies are a morphological key feature of severe alcoholic liver cell injury (alcoholic hepatitis) and the morphological expression of dysregulation and derangement of the intermediate filament cytoskeleton of the hepatocyte. Their pathogenesis is still unclear. Studies on Mallory body formation may not only help to elucidate the mechanisms of liver cell injury associated with alcoholic hepatitis, but may also contribute to our understanding of the regulation and function of the intermediate filament cytoskeleton.

Topics: Animals; Chemical and Drug Induced Liver Injury; Colchicine; Cytoskeleton; Electrophoresis, Polyacrylamide Gel; Endoplasmic Reticulum; Fluorescent Antibody Technique; Griseofulvin; Hepatitis, Alcoholic; Humans; Isoantibodies; Isoelectric Focusing; Keratins; Liver; Liver Cirrhosis, Alcoholic; Mice; Microscopy, Electron; Rats

Topics: Actomyosin; Animals; Cytoskeleton; Desmin; Glial Fibrillary Acidic Protein; Hepatitis, Alcoholic; Humans; Intermediate Filament Proteins; Keratins; Liver; Mice; Microtubules; Protein Precursors; Skin Diseases; Vimentin

Alcoholic hepatitis (AH) is associated with cytokeratin 8 and 18 (CK8/18) accumulation as cytoplasmic inclusion bodies, termed Mallory bodies (MBs). Studies with MB mouse models and cultured hepatocytes suggested that CK8/18 hyperphosphorylation might be involved in MB formation. However, no data exist on phosphorylation of CK8/18 in human AH. In this study, antibodies that selectively recognize phosphorylated epitopes of CK8 or CK18 were used to analyze CK8/18 phosphorylation states in normal human and murine livers, human AH biopsies, and livers of 3,5-diethoxycarbonyl-1, 4-dihydrocollidine (DDC)-intoxicated mice, the last serving as model for MB induction. Hepatocyte cytokeratins become hyperphosphorylated at multiple sites in AH and in DDC-intoxicated mice. Hyperphosphorylation of CK8/18 occurred rapidly, after 1 day of DDC intoxication and preceded architectural changes of the cytoskeleton. In long-term DDC-intoxicated mice as well as in human AH, MBs preferentially contain hyperphosphorylated CK8/18 as compared with the cytoplasmic cytokeratin intermediate filament network suggesting that CK8/18 hyperphosphorylation may play a contributing role in MB pathogenesis. Furthermore, the site-specific phosphorylation of cytokeratin in different stages of MB induction provides indirect evidence for the involvement of a variety of protein kinases known to be activated in stress responses, mitosis, and apoptosis.

Topics: Animals; Dicarbethoxydihydrocollidine; Hepatitis, Alcoholic; Humans; Inclusion Bodies; Keratins; Liver; Male; Mice; Phosphorylation

Dephosphorylation of keratin intermediate filaments (IF) in livers from ethanol-fed rats relative to controls occurs concurrently with a reorganization of the distribution of IF in the cells. One possible molecular mechanism for this reorganization is a phosphorylation-induced conformational change in the keratin that propagates as a change in the polymerization of the keratin subunits. To test this hypothesis, the structure of liver keratin IF, from both control and alcohol-fed rats, was explored by circular dichroism (CD), tryptophan fluorescence quenching, and 13C nuclear magnetic resonance (NMR). Keratin IF were isolated from livers of control rats and from livers of rats that had ethanol included in their feed for 6-40 weeks. A significant decrease in the intensity of the CD spectrum of keratin IF from livers of ethanol-treated animals, relative to controls, was observed. These data suggested either that a change in conformation or an increase in conformational motility in the keratin IF from ethanol-treated animals occurred as a result of the ethanol-induced dephosphorylation. 13C NMR data were obtained to distinguish between these two possibilities. An increase in resonance intensity of some 13C NMR resonances was observed in the keratin IF from livers of ethanol-treated animals, relative to controls. The CD and NMR data were therefore consistent with an increase in conformational motility of the rod domain in these keratin IF. No significant change was observed in the quenching of tryptophan fluorescence by KI. The change in protein dynamics detected in these experiments could be the molecular basis for the alteration of keratin IF organization in alcoholic hepatitis.

Topics: Animals; Circular Dichroism; Ethanol; Fluorescence; Hepatitis, Alcoholic; Intermediate Filaments; Keratins; Liver; Magnetic Resonance Spectroscopy; Male; Phosphates; Phosphorylation; Protein Conformation; Rats; Rats, Sprague-Dawley; Tryptophan

In the present study, the frequency and the distribution pattern of immunoreactive hepatocytic cytokeratin (CK) inclusions was investigated using the monoclonal antibody (MAb) CAM 5.2 detecting CKs 8, 18 and 19. The CK antigenicity of the inclusions was confirmed on frozen sections with MAbs for the CKs 7, 8, 17, 18 and 19. The frequency of hepatocytic CK aggregates was compared to the presence of non-alcoholic and alcoholic liver disease (ALD) as well as to the average all-year daily ethanol intake of 195 consecutive males subjected to medico-legal autopsy. Hepatocytic CK inclusions were infrequent in patients with normal liver histology, portal fibrosis and/or portal inflammation. In ALD, however, inclusions were observed in 35.6% of patients with fatty liver, in 63.2% of patients with alcoholic hepatitis, in 30.8% of patients with bridging fibrosis and in 60.0% of patients with liver cirrhosis. In all specimens studied, the inclusions were reactive only for CKs 8 and 18, CKs 7, 17, and 19 being unreactive. The frequency of inclusion bodies increased, paralleling increasing average all-year daily alcohol consumption. Compared to non-drinkers, a daily intake of between 40 and 80 g of absolute alcohol was associated with a statistically significantly (relative risk, RR = 6.6) increased risk of formation of aggregates. Similarly, daily consumption exceeding 80 g was related to increased (RR = 6.0) frequency of CK aggregates. The frequency of full-blown "classical" Mallory bodies (MBs) was, however, increased (RR = 8.9) only in patients with a daily intake exceeding 160 g.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Adult; Aged; Alcohol Drinking; Fatty Liver, Alcoholic; Hepatitis, Alcoholic; Humans; Immunohistochemistry; Inclusion Bodies; Keratins; Liver; Liver Cirrhosis, Alcoholic; Liver Diseases, Alcoholic; Male; Middle Aged

Mallory bodies (MBs) are characteristics morphologic features of alcoholic hepatitis and can be produced in mouse hepatocytes by chronic griseofulvin (GF) intoxication. The formation of MBs, which share some immunological, biochemical, and ultrastructural features with cytokeratin (CK) filaments of normal liver, is accompanied by derangement and even loss of the CK cytoskeleton of hepatocytes ("empty cells") as revealed by immunofluorescence microscopy. To clarify whether this diminution or lack of CK-related staining of MB-containing hepatocytes was due to loss of CK filaments or changes in antigenicity or accessibility of antigenic determinants immunohistochemical studies using a battery of monoclonal and polyclonal CK antibodies were performed. It could be shown that all these antibodies directed against different CK polypeptide components and antigenic determinants of CKs revealed a highly reduced or even undetectable cytoplasmic CK meshwork in most cells with fully developed large MBs. In the light of our present knowledge of the organization of CK intermediate filaments, these results indicate that the phenomenon of the "empty cells" reflects a diminution of CK meshwork rather than altered antigenic determinants.

Topics: Animals; Antibodies, Monoclonal; Bile Ducts, Intrahepatic; Desmin; Electrophoresis, Polyacrylamide Gel; Griseofulvin; Hepatitis, Alcoholic; Humans; Immunoblotting; Inclusion Bodies; Intermediate Filaments; Keratins; Liver; Male; Mice; Microscopy, Fluorescence; Vimentin

Antibodies raised against prekeratin intensely and specifically stain, in immunofluorescence microscopy, Mallory bodies ("alcoholic hyalin") present in livers of human alcoholics and griseofulyin-treated mice. The high sensitivity of this method allows the identification of small distinct cytoplasmic structures that are observed during early stages of Mallory body formation, especially frequent in the perinuclear cytoplasm, as well as during stages of Mallory body disintegration and disappearance, such as after withdrawal of the drug. In the latter situation, the prekeratin-containing small particles exhibit a characteristic pattern of arrangement in the hepatocyte periphery. Electron microscopy illustrates that such small bodies are heap-like aggregates of typical Mallory body filaments. Immunofluorescence studies with antibodies to isolated prekeratin polypeptides from bovine hoof or muzzle epidermis show that Mallory body filaments, in particular those in human liver, are immunologically more closely related to prekeratin of tonofilaments from living epidermal cells (stratum spinosum). The data indicate that Mallory bodies contain a pathologic form of prekeratin-like material. They also suggest that disorders of cytoskeletal structures of the intermediate-sized filament class are associated with specific diseases and can be visualized and characterized by immunofluorescence microscopy by using antibodies to constitutive proteins of such filaments.

Topics: Animals; Cytoplasmic Granules; Fluorescent Antibody Technique; Griseofulvin; Hepatitis, Alcoholic; Humans; Keratins; Liver Cirrhosis, Alcoholic; Liver Cirrhosis, Experimental; Mice; Protein Precursors