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Wang W, Xu L, Jiang G, Li Z, Bi YH, Zhou ZG. Characterization of a novel γ-type carbonic anhydrase, Sjγ-CA2, in Saccharina japonica: Insights into carbon concentration mechanism in macroalgae. Int J Biol Macromol 2024; 263:130506. [PMID: 38423426 DOI: 10.1016/j.ijbiomac.2024.130506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2023] [Revised: 02/23/2024] [Accepted: 02/26/2024] [Indexed: 03/02/2024]
Abstract
Carbonic anhydrase (CA) is a crucial component of CO2-concentrating mechanism (CCM) in macroalgae. In Saccharina japonica, an important brown seaweed, 11 CAs, including 5 α-, 3 β-, and 3 γ-CAs, have been documented. Among them, one α-CA and one β-CA were localized in the periplasmic space, one α-CA was found in the chloroplast, and one γ-CA was situated in mitochondria. Notably, the known γ-CAs have predominantly been identified in mitochondria. In this study, we identified a chloroplastic γ-type CA, Sjγ-CA2, in S. japonica. Based on the reported amino acid sequence of Sjγ-CA2, the epitope peptide for monoclonal antibody production was selected as 165 Pro-305. After purification and specificity identification, anti-SjγCA2 monoclonal antibody was employed in immunogold electron microscopy. The results illustrated that Sjγ-CA2 was localized in the chloroplasts of both gametophytes and sporophytes of S. japonica. Subsequently, immunoprecipitation coupled with LC-MS/MS analysis revealed that Sjγ-CA2 mainly interacted with photosynthesis-related proteins. Moreover, the first 65 amino acids at N-terminal of Sjγ-CA2 was identified as the chloroplast transit peptide by the transient expression of GFP-SjγCA2 fused protein in tabacco. Real-time PCR results demonstrated an up-regulation of the transcription of Sjγ-CA2 gene in response to high CO2 concentration. These findings implied that Sjγ-CA2 might contribute to minimizing the leakage of CO2 from chloroplasts and help maintaining a high concentration of CO2 around Rubisco.
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Affiliation(s)
- Wen Wang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources Conferred By Ministry of Education, Shanghai Ocean University, Shanghai 201306, China
| | - Ling Xu
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources Conferred By Ministry of Education, Shanghai Ocean University, Shanghai 201306, China
| | - Gang Jiang
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources Conferred By Ministry of Education, Shanghai Ocean University, Shanghai 201306, China
| | - Zhi Li
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources Conferred By Ministry of Education, Shanghai Ocean University, Shanghai 201306, China
| | - Yan-Hui Bi
- Key Laboratory of Exploration and Utilization of Aquatic Genetic Resources Conferred By Ministry of Education, Shanghai Ocean University, Shanghai 201306, China.
| | - Zhi-Gang Zhou
- International Research Center for Marine Biosciences Conferred By Ministry of Science and Technology, Shanghai Ocean University, Shanghai 201306, China.
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Hong MH, Weng IC, Li FY, Liu FT. Visualization of Cytosolic Galectin Accumulation Around Damaged Vesicles and Organelles. Methods Mol Biol 2022; 2442:353-365. [PMID: 35320535 DOI: 10.1007/978-1-0716-2055-7_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Galectins are animal lectins that recognize β-galactoside and bind glycans. Recent studies have indicated that cytosolic galectins recognize cytosolically exposed glycans and accumulate around endocytic vesicles or organelles damaged by various disruptive substances. Accumulated galectins engage other cytosolic proteins toward damaged vesicles, leading to cellular responses, such as autophagy. Disruptive substances include bacteria, viruses, particulate matters, and protein aggregates; thus, this process is implicated in the pathogenesis of various diseases. In this chapter, we describe methods for studying three disruptive substances: photosensitizers, Listeria monocytogenes, and Helicobacter pylori. We summarize the tools used for the detection of cytosolic galectin accumulation around damaged vesicles.
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Affiliation(s)
- Ming-Hsiang Hong
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - I-Chun Weng
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Fang-Yen Li
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan
| | - Fu-Tong Liu
- Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan.
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Hasan-Olive MM, Hansson HA, Enger R, Nagelhus EA, Eide PK. Blood-Brain Barrier Dysfunction in Idiopathic Intracranial Hypertension. J Neuropathol Exp Neurol 2020; 78:808-818. [PMID: 31393574 DOI: 10.1093/jnen/nlz063] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 06/01/2019] [Accepted: 06/27/2019] [Indexed: 12/18/2022] Open
Abstract
Idiopathic intracranial hypertension (IIH) is traditionally considered benign and characterized by symptoms related to increased intracranial pressure, including headache and impaired vision. We have previously demonstrated that brains of IIH patients exhibit patchy astrogliosis, increased perivascular expression of the water channel aquaporin-4 (AQP4) as well as degenerating pericyte processes and capillary basement membranes. Given the established association between pericyte degeneration and blood-brain barrier (BBB) dysfunction, we investigated blood protein leakage by light microscopic immunohistochemistry. We also assessed perivascular AQP4 expression by immunogold transmission electron microscopy. The study included 14 IIH patients and 14 reference (REF) subjects undergoing neurosurgery for epilepsy, aneurysm, or tumor. Evidence of BBB dysfunction, measured as area extravasated fibrinogen/fibrin, was significantly more pronounced in IIH than REF individuals. The extent of extravasated fibrinogen was positively correlated with increasing degree of astrogliosis and vascular AQP4 immunoreactivity, determined by light microscopy. Immunogold transmission electron microscopy revealed no overall changes in AQP4 expression at astrocytic vascular endfeet in IIH (n = 8) compared to REF (n = 11) individuals. Our results provide evidence of BBB leakage in IIH, signifying that IIH is a more serious neurodegenerative disease than previously considered.
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Affiliation(s)
- Md Mahdi Hasan-Olive
- Department of Neurosurgery, Oslo University Hospital - Rikshospitalet.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Hans-Arne Hansson
- Institute of Biomedicine, University of Gothenburg, Göteborg, Sweden
| | - Rune Enger
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo.,Department of Neurology, Oslo University Hospital - Rikshospitalet, Oslo, Norway
| | - Erlend A Nagelhus
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo.,Department of Neurology, Oslo University Hospital - Rikshospitalet, Oslo, Norway
| | - Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital - Rikshospitalet.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
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Hasan-Olive MM, Enger R, Hansson HA, Nagelhus EA, Eide PK. Pathological mitochondria in neurons and perivascular astrocytic endfeet of idiopathic normal pressure hydrocephalus patients. Fluids Barriers CNS 2019; 16:39. [PMID: 31849332 PMCID: PMC6918585 DOI: 10.1186/s12987-019-0160-7] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2019] [Accepted: 12/05/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND A growing body of evidence suggests that the accumulation of amyloid-β and tau (HPτ) in the brain of patients with the dementia subtype idiopathic normal pressure hydrocephalus (iNPH) is associated with delayed extravascular clearance of metabolic waste. Whether also clearance of intracellular debris is affected in these patients needs to be examined. Hypothetically, defective extra- and intra-cellular clearance of metabolites may be instrumental in the neurodegeneration and dementia characterizing iNPH. This study explores whether iNPH is associated with altered mitochondria phenotype in neurons and astrocytes. METHODS Cortical brain biopsies of 9 reference (REF) individuals and 30 iNPH patients were analyzed for subcellular distribution and morphology of mitochondria using transmission electron microscopy. In neuronal soma of REF and iNPH patients, we identified normal, pathological and clustered mitochondria, mitochondria-endoplasmic reticulum contact sites and autophagic vacuoles. We also differentiated normal and pathological mitochondria in pre- and post-synaptic nerve terminals, as well as in astrocytic endfoot processes towards vessels. RESULTS We found a high prevalence of pathological mitochondria in neuronal soma and pre- and post-synaptic terminals, as well as increased mitochondrial clustering, and altered number of mitochondria-endoplasmic reticulum contact sites in iNPH. Non-fused autophagic vacuoles were more abundant in neuronal soma of iNPH patients, suggestive of cellular clearance failure. Moreover, the length of postsynaptic densities was reduced in iNPH, potentially related to reduced synaptic activity. In astrocytic endfoot processes, we also found increased number, area and area fraction of pathological mitochondria in iNPH patients. The proportion of pathological mitochondria correlated significantly with increasing degree of astrogliosis and reduced perivascular expression of aquaporin-4 (AQP4), assessed by light microscopy immunohistochemistry. CONCLUSION Our results provide evidence of mitochondrial pathology and signs of impaired cellular clearance in iNPH patients. The results indicate that iNPH is a neurodegenerative disease with close similarity to Alzheimer's disease.
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Affiliation(s)
- Md Mahdi Hasan-Olive
- Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, 0027, Oslo, Norway.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Rune Enger
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway.,Department of Neurology, Oslo University Hospital-Rikshospitalet, 0027, Oslo, Norway
| | - Hans-Arne Hansson
- Institute of Biomedicine, University of Gothenburg, Göteborg, Sweden
| | - Erlend A Nagelhus
- GliaLab and Letten Centre, Division of Physiology, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, 0317, Oslo, Norway.,Department of Neurology, Oslo University Hospital-Rikshospitalet, 0027, Oslo, Norway
| | - Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, 0027, Oslo, Norway. .,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
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Qiao Q, Djediat C, Huet H, Duval C, Le Manach S, Bernard C, Edery M, Marie B. Subcellular localization of microcystin in the liver and the gonads of medaka fish acutely exposed to microcystin-LR. Toxicon 2019; 159:14-21. [PMID: 30629997 DOI: 10.1016/j.toxicon.2018.12.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 11/24/2018] [Accepted: 12/25/2018] [Indexed: 11/29/2022]
Abstract
Among the diverse toxic components produced by cyanobacteria, microcystins (MCs) are one of the most toxic and notorious cyanotoxin groups. Besides their potent hepatotoxicity, MCs have been revealed to induce potential reproductive toxicity in various animal studies. However, little is still known regarding the distribution of MCs in the reproductive organ, which could directly affect reproductive cells. In order to respond to this question, an acute study was conducted in adult medaka fish (model animal) gavaged with 10 μg.g-1 body weight of pure MC-LR. The histological and immunohistochemical examinations reveal an intense distribution of MC-LR within hepatocytes along with a severe liver lesion in the toxin-treated female and male fish. Besides being accumulated in the hepatocytes, MC-LR was also found in the connective tissue of the ovary and the testis, as well as in oocytes and degenerative spermatocyte-like structures but not spermatocytes. Both liver and gonad play important roles in the reproductive process of oviparous vertebrates. This observation constitutes the first observation of the presence of MC-LR in reproductive cells (female, oocytes) of a vertebrate model with in vivo study. Our results, which provide intracellular localization of MC-LR in the gonad, advance our understanding of the potential reproductive toxicity of MC-LR in fish.
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Affiliation(s)
- Qin Qiao
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Muséum National d'Histoire Naturelle, CP 39, 12 Rue Buffon, 75005, Paris, France
| | - Chakib Djediat
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Muséum National d'Histoire Naturelle, CP 39, 12 Rue Buffon, 75005, Paris, France
| | - Hélène Huet
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Muséum National d'Histoire Naturelle, CP 39, 12 Rue Buffon, 75005, Paris, France; Ecole Nationale Vétérinaire d'Alfort, Université Paris-Est, BioPôle Alfort, 94700, Maisons-Alfort, France
| | - Charlotte Duval
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Muséum National d'Histoire Naturelle, CP 39, 12 Rue Buffon, 75005, Paris, France
| | - Séverine Le Manach
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Muséum National d'Histoire Naturelle, CP 39, 12 Rue Buffon, 75005, Paris, France
| | - Cécile Bernard
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Muséum National d'Histoire Naturelle, CP 39, 12 Rue Buffon, 75005, Paris, France
| | - Marc Edery
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Muséum National d'Histoire Naturelle, CP 39, 12 Rue Buffon, 75005, Paris, France
| | - Benjamin Marie
- UMR 7245 MNHN/CNRS Molécules de Communication et Adaptation des Micro-organismes, Muséum National d'Histoire Naturelle, CP 39, 12 Rue Buffon, 75005, Paris, France.
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Mattoscio D, Raimondi A, Tacchetti C, Chiocca S. Immunogold Electron Microscopy of the Autophagosome Marker LC3. Bio Protoc 2017; 7:e2648. [PMID: 34595311 PMCID: PMC8438370 DOI: 10.21769/bioprotoc.2648] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Revised: 11/20/2017] [Accepted: 11/25/2017] [Indexed: 01/24/2023] Open
Abstract
Even though autophagy was firstly observed by transmission electron microscopy already in the 1950s (reviewed in Eskelinen et al., 2011 ), nowadays this technique remains one of the most powerful systems to monitor autophagic processes. The autophagosome, an LC3-positive double membrane structures enclosing cellular materials, represents the key organelle in autophagy and its simple visualization and/or numeration allow to draw important conclusions about the autophagic flux. Therefore, the accurate identification of autophagosomes is crucial for a comprehensive and detailed dissection of autophagy. Here we present a simple protocol to identify autophagosomes by transmission electron microscopy coupled to immunogold labeling of LC3 starting from a relatively low cell number, which we recently developed to follow the autophagic pathway during viral-mediated human carcinogenesis.
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Affiliation(s)
- Domenico Mattoscio
- Department of Medical, Oral, and Biotechnology Science, University of Chieti-Pescara, Chieti, Italy
- Center on Aging Science and Translational Medicine (CeSI-MeT) “G. d’Annunzio”, University of Chieti-Pescara, Chieti, Italy
| | - Andrea Raimondi
- Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy
| | - Carlo Tacchetti
- Experimental Imaging Center, IRCCS San Raffaele Scientific Institute, Milan, Italy
- Medical School, University Vita.Salute San Raffaele, Milan, Italy
| | - Susanna Chiocca
- Department of Experimental Oncology, European Institute of Oncology, Milan, Italy
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Bogolyubova IO, Bogolyubov DS. Detection of RNA Polymerase II in Mouse Embryos During Zygotic Genome Activation Using Immunocytochemistry. Methods Mol Biol 2017; 1605:147-59. [PMID: 28456963 DOI: 10.1007/978-1-4939-6988-3_10] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
Mammalian pre-implantation embryos represent a highly dynamic experimental model for comparative studies of nuclear structure and functions in the context of gradual reactivation of transcription. Here, we present details of the methods that allow localizing RNA polymerase II in mouse pre-implantation embryos with specific antibodies, using fluorescent/confocal and electron microscopy. We stress the special aspects of immunolabeling protocols in respect to the embryonic material. We made a special emphasis on the essential steps preceding the immunocytochemical experiments. In particular, we consider the procedures of female hormonal stimulation and embryo collection. The described approaches are also applicable to study other nuclear proteins.
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Valdés G, Acuña S, Munizaga A, Soto GX, Figueroa CD. Utero-placental cellular and nuclear expression of bradykinin B2 receptors in normal and preeclamptic pregnancies. Pregnancy Hypertens 2016; 6:30-7. [PMID: 26955769 DOI: 10.1016/j.preghy.2016.01.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 01/19/2016] [Indexed: 11/20/2022]
Abstract
The bradykinin type 2 receptor (B2R), main effector of the pleiotropic kallikrein-kinin system (KKS), has been localized in the key sites related to placentation in human, rat and guinea pig utero-placental units. The present study was directed to characterize the content, the cellular and subcellular localization of B2R in the villi and basal plate of placentas from normal and preeclamptic pregnancies by means of western blotting, immunohistochemistry and immunoelectron microscopy. The protein content of B2R was demonstrated in both placental zones. The villous placenta of normal and preeclamptic pregnancies expressed B2R in syncytiotrophoblast and fetal endothelium; the basal plate displayed B2R in extravillous trophoblasts and decidual cells. Lastly, immunogold electron microscopy revealed B2R in fetal endothelium, syncytiotrophoblast, extravillous cytotrophoblasts and decidual cells; in all cell types the receptor was mainly located in the cytosol and nucleus. The protein content of placental homogenates and the immunoreactivity in the different cells types did not differ between both study groups; however the abundance of nuclear immunogold B2R positive beads in extravillous trophoblasts was greater in the normal than in the preeclamptic placentas. The purpose of describing nuclear B2R in the utero-placental unit, and its increment in normal extravillous trophoblasts, is to stimulate the study of the functional pathways that may be relevant to understand the local role of the B2R in normal and preeclamptic gestation.
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Carmo LAS, Dias FF, Malta KK, Amaral KB, Shamri R, Weller PF, Melo RCN. Expression and subcellular localization of the Qa-SNARE syntaxin17 in human eosinophils. Exp Cell Res 2015; 337:129-35. [PMID: 26254897 DOI: 10.1016/j.yexcr.2015.07.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2015] [Revised: 06/29/2015] [Accepted: 07/06/2015] [Indexed: 01/21/2023]
Abstract
BACKGROUND SNARE members mediate membrane fusion during intracellular trafficking underlying innate and adaptive immune responses by different cells. However, little is known about the expression and function of these proteins in human eosinophils, cells involved in allergic, inflammatory and immunoregulatory responses. Here, we investigate the expression and distribution of the Qa-SNARE syntaxin17 (STX17) within human eosinophils isolated from the peripheral blood. METHODS Flow cytometry and a pre-embedding immunonanogold electron microscopy (EM) technique that combines optimal epitope preservation and secondary Fab-fragments of antibodies linked to 1.4 nm gold particles for optimal access to microdomains, were used to investigate STX17. RESULTS STX17 was detected within unstimulated eosinophils. Immunogold EM revealed STX17 on secretory granules and on granule-derived vesiculotubular transport carriers (Eosinophil Sombrero Vesicles-EoSVs). Quantitative EM analyses showed that 77.7% of the granules were positive for STX17 with a mean±SEM of 3.9±0.2 gold particles/granule. Labeling was present on both granule outer membranes and matrices while EoSVs showed clear membrane-associated labeling. STX17 was also present in secretory granules in eosinophils stimulated with the cytokine tumor necrosis factor alpha (TNF-α) or the CC-chemokine ligand 11 CCL11 (eotaxin-1), stimuli that induce eosinophil degranulation. The number of secretory granules labeled for STX17 was significantly higher in CCL11 compared with the unstimulated group. The level of cell labeling did not change when unstimulated cells were compared with TNF-α-stimulated eosinophils. CONCLUSIONS The present study clearly shows by immunanonogold EM that STX17 is localized in eosinophil secretory granules and transport vesicles and might be involved in the transport of granule-derived cargos.
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Yokomori H, Oda M, Ogi M, Wakabayashi G, Kawachi S, Yoshimura K, Nagai T, Kitajima M, Nomura M, Hibi T. Expression of adhesion molecules on mature cholangiocytes in canal of Hering and bile ductules in wedge biopsy samples of primary biliary cirrhosis. World J Gastroenterol 2005; 11:4382-9. [PMID: 16038038 PMCID: PMC4434666 DOI: 10.3748/wjg.v11.i28.4382] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To examine the expression of intercellular adhesion molecule-1 (ICAM-1) and lymphocyte function-associated antigen-1 (LFA-1) expression on canals of Hering (CoH) and bile ductules associated with the autoimmune process of bile duct destruction in primary biliary cirrhosis (PBC).
METHODS: Ten wedged liver biopsies of PBC (five cases each of stages 2 and 3) were studied. The liver specimens were processed for transmission electron microscopy. Immunohistochemistry was performed using anti-ICAM-1 and anti-LFA-1 mouse mAbs. In situ hybridization was done to examine the messenger RNA expression of ICAM-1 in formalin-fixed, paraffin-embedded sections using peptide nucleic acid probes and the catalyzed signal amplification (CSA) technique. Immunogold-silver staining for electron microscopy was performed using anti-ICAM and anti-LFA-1 mouse mAbs. The immunogold particles on epithelial cells of bile ductules and cholangiocytes of CoH cells were counted and analyzed semi-quantitatively. Western blotting was performed to confirm ICAM-1 protein expression.
RESULTS: In liver tissues of PBC patients, immunohi-stochemistry showed aberrant ICAM-1 expression on the plasma membrane of epithelial cells lining bile ductules, and also on mature cholangiocytes but not on hepatocytes in CoH. LFA-1-positive lymphocytes were closely associated with epithelial cells in bile ductules. ICAM-1 expression at protein level was confirmed by Western blot. In situhybridization demonstrated ICAM-1 mRNA expression in bile ductules and LFA-1 mRNA in lymphocytes infiltrating the bile ductules. By immunoelectron microscopy, ICAM-1 was demonstrated on the basal surface of epithelial cells in bile ductules and on the luminal surfaces of cholangiocytes in damaged CoH. Cells with intermediate morphology resembling progenitor cells in CoH were not labeled with ICAM-1 and LFA-1.
CONCLUSION: De novo expression of ICAM-1 both on mature cholangiocytes in CoH and epithelial cells in bile ductules in PBC implies that lymphocyte-induced destruction through adhesion by ICAM-1 and binding of LFA-1-expressing activated lymphocytes takes place not only in bile ductules but also in the CoH.
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Affiliation(s)
- Hiroaki Yokomori
- Kitasato Institute Medical Center Hospital, 121-1 Arai, Kitamotoshi, Saitama 364-8501, Japan.
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