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Wang S, Zhang X, Leng S, Zhang Y, Li J, Peng J, Zhou Z, Feng Q, Hu X. SIRT1 single-nucleotide polymorphisms are associated with corticosteroid sensitivity in primary immune thrombocytopenia patients. Ann Hematol 2021; 100:2453-2462. [PMID: 34269838 DOI: 10.1007/s00277-021-04583-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Accepted: 06/22/2021] [Indexed: 12/24/2022]
Abstract
BACKGROUND Primary immune thrombocytopenia (ITP) is an autoimmune disorder characterized by decreased platelet count. While corticosteroids are a useful first-line therapy for ITP patients, their long-term effectiveness is limited, and the determinants of corticosteroid sensitivity in ITP patients remain largely unknown. Sirtuin 1 (SIRT1), a member of the mammalian sirtuin family, is related to the anti-inflammatory effects of corticosteroids. Here, we investigate the contribution of the SIRT1 single-nucleotide polymorphisms (SNPs) rs12778366 and rs4746720 to ITP susceptibility. METHODS We recruited 330 ITP patients and 309 healthy controls from Han population, and performed genotyping of SIRT1 rs12778366 and rs4746720 using a MassARRAY system. The results were validated in another 55 ITP patients from ethnic minorities. RESULTS Using clinical data of patients and controls from Han polulation, including corticosteroid sensitivity, susceptibility, refractoriness, and severity, our results revealed that the CC/TC genotypes of SIRT1 rs12778366 were associated with a 2.034-fold increased risk of corticosteroid resistance compared to the homozygous major TT genotype (dominant, CC/TC vs. TT, OR = 2.034, 95% CI = 1.039-3.984, p = 0.038). In contrast, the CC/CT genotype of SIRT1 rs4746720 showed a 0.560-fold decreased risk of corticosteroid resistance (dominant, 95% CI = 0.321-0.976, OR = 0.560, p = 0.041). The C allele substitute in SIRT1 rs12778366 was significantly associated with the corticosteroid sensitivity of ITP patients (p = 0.021). The similar results were obtained in minority ITP patients. CONCLUSION This study indicates that SIRT1 rs12778366 and rs4746720 may be genetic factors related to corticosteroid sensitivity in ITP patients.
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Affiliation(s)
- Shuwen Wang
- Department of Hematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Xiaoyu Zhang
- Department of Hematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Shaoqiu Leng
- Department of Hematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Yanqi Zhang
- Shandong Provincial Key Laboratory of Immunohematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Ju Li
- Shandong Provincial Key Laboratory of Immunohematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Jun Peng
- Department of Hematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Disease Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin, China
| | - Zeping Zhou
- Department of Hematology, the Second Affiliated Hospital of Kunming Medical University, Kunming, Yunnan, China.
| | - Qi Feng
- Department of Hematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
| | - Xiang Hu
- Shandong Provincial Key Laboratory of Immunohematology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China.
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Penjweini R, Deville S, Haji Maghsoudi O, Notelaers K, Ethirajan A, Ameloot M. Investigating the effect of poly-l-lactic acid nanoparticles carrying hypericin on the flow-biased diffusive motion of HeLa cell organelles. ACTA ACUST UNITED AC 2017; 71:104-116. [PMID: 28722126 DOI: 10.1111/jphp.12779] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Indexed: 01/04/2023]
Abstract
OBJECTIVES In this study, we investigate in human cervical epithelial HeLa cells the intracellular dynamics and the mutual interaction with the organelles of the poly-l-lactic acid nanoparticles (PLLA NPs) carrying the naturally occurring hydrophobic photosensitizer hypericin. METHODS Temporal and spatiotemporal image correlation spectroscopy was used for the assessment of the intracellular diffusion and directed motion of the nanocarriers by tracking the hypericin fluorescence. Using image cross-correlation spectroscopy and specific fluorescent labelling of endosomes, lysosomes and mitochondria, the NPs dynamics in association with the cell organelles was studied. Static colocalization experiments were interpreted according to the Manders' overlap coefficient. KEY FINDINGS Nanoparticles associate with a small fraction of the whole-organelle population. The organelles moving with NPs exhibit higher directed motion compared to those moving without them. The rate of the directed motion drops substantially after the application of nocodazole. The random component of the organelle motions is not influenced by the NPs. CONCLUSIONS Image correlation and cross-correlation spectroscopy are most appropriate to unravel the motion of the PLLA nanocarrier and to demonstrate that the rate of the directed motion of organelles is influenced by their interaction with the nanocarriers. Not all PLLA-hypericin NPs are associated with organelles.
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Affiliation(s)
- Rozhin Penjweini
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium.,NHLBI Laboratory of Molecular Biophysics, National Institutes of Health, Bethesda, MD, USA
| | - Sarah Deville
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium.,Environmental Risk and Health Unit, Flemish Institute for Technological Research, Mol, Belgium
| | - Omid Haji Maghsoudi
- Department of Bioengineering, School of Engineering, Temple University, Philadelphia, PA, USA
| | - Kristof Notelaers
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium.,Division of Nanoscopy, Maastricht University, Maastricht, The Netherlands
| | - Anitha Ethirajan
- Institute for Materials Research, IMO-IMOMEC, Hasselt University, Diepenbeek, Belgium
| | - Marcel Ameloot
- Biomedical Research Institute, Hasselt University, Diepenbeek, Belgium
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Oppenheimer H, Gabay O, Meir H, Haze A, Kandel L, Liebergall M, Gagarina V, Lee EJ, Dvir-Ginzberg M. 75-kd sirtuin 1 blocks tumor necrosis factor α-mediated apoptosis in human osteoarthritic chondrocytes. ACTA ACUST UNITED AC 2012; 64:718-28. [PMID: 21987377 DOI: 10.1002/art.33407] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
OBJECTIVE Sirtuin 1 (SirT1) has been implicated in the regulation of human cartilage homeostasis and chondrocyte survival. Exposing human osteoarthritic (OA) chondrocytes to tumor necrosis factor α (TNFα) generates a stable and enzymatically inactive 75-kd form of SirT1 (75SirT1) via cathepsin B-mediated cleavage. Because 75SirT1 is resistant to further degradation, we hypothesized that it has a distinct role in OA, and the present study was undertaken to identify this role. METHODS The presence of cathepsin B and 75SirT in OA and normal human chondrocytes was analyzed. Confocal imaging of SirT1 was used to monitor its subcellular trafficking following TNFα stimulation. Coimmunofluorescence staining for cathepsin B, mitochondrial cytochrome oxidase subunit IV, and lysosome-associated membrane protein 1 together with SirT1 was performed. Human chondrocytes were tested for apoptosis by fluorescence-activated cell sorter analysis and immunoblotting for caspases 3 and 8. Human chondrocyte mitochondrial extracts were obtained and analyzed for 75SirT1-cytochrome c association. RESULTS Confocal imaging and immunoblot analyses following TNFα challenge of human chondrocytes demonstrated that 75SirT1 was exported to the cytoplasm and colocalized with the mitochondrial membrane. Consistent with this, immunoprecipitation and immunoblot analyses revealed that 75SirT1 is enriched in mitochondrial extracts and associates with cytochrome c following TNFα stimulation. Preventing nuclear export of 75SirT1 or reducing levels of full-length SirT1 and 75SirT1 augmented chondrocyte apoptosis in the presence of TNFα. Levels of cathepsin B and 75SirT1 were elevated in OA versus normal chondrocytes. Additional analyses showed that human chondrocytes exposed to OA-derived synovial fluid generated the 75SirT1 fragment. CONCLUSION These data suggest that 75SirT1 promotes chondrocyte survival following exposure to proinflammatory cytokines.
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Affiliation(s)
- Hanna Oppenheimer
- Laboratory of Cartilage Biology, Institute of Dental Sciences, Faculty of Dental Medicine, Hebrew University, Hadassah Ein Kerem, Jerusalem, Israel
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Dasgupta S, Hoque MO, Upadhyay S, Sidransky D. Forced cytochrome B gene mutation expression induces mitochondrial proliferation and prevents apoptosis in human uroepithelial SV-HUC-1 cells. Int J Cancer 2009; 125:2829-35. [PMID: 19569044 DOI: 10.1002/ijc.24701] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Mitochondria encoded Cytochrome B (CYTB) gene mutations were reported in tumors of different anatomic origin but the functional significance of these mutations are not well studied. Earlier, we found a 7-amino acid deletion mutation in the CYTB gene in a primary bladder cancer patient. In the present study, we overexpressed this 7-amino acid deletion mutation of CYTB gene in SV-40 transformed human uroepithelial HUC-1 cells. The nuclear transcribed mitochondrial CYTB (mtCYTB) was targeted into the mitochondria and generated increased copies of mitochondria and mitochondrial COX-I protein in the transfected HUC-1 cells. The proapoptotic protein Bax largely remained confined to the cytoplasm of the mtCYTB transfected HUC-1 cells without release of Cytochrome C. The downstream apoptotic proteins PARP also remained uncleaved along with increased Lamin B1 in the mtCYTB transfected cells. Our results demonstrate that forced overexpression of mtCYTB in transformed human uroepithelial HUC-1 cells triggered mitochondrial proliferation and induction of an antiapoptotic signaling cascade favoring sustained cellular growth. Coding mitochondrial DNA mutations appear to have significant functional contribution in tumor progression.
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Affiliation(s)
- Santanu Dasgupta
- Department of Otolaryngology-Head and Neck Surgery, Division of Head and Neck Cancer Research, Johns Hopkins University, North Baltimore, MD 21231, USA
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Solá S, Castro RE, Kren BT, Steer CJ, Rodrigues CMP. Modulation of nuclear steroid receptors by ursodeoxycholic acid inhibits TGF-beta1-induced E2F-1/p53-mediated apoptosis of rat hepatocytes. Biochemistry 2004; 43:8429-38. [PMID: 15222754 DOI: 10.1021/bi049781x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have recently shown that both ursodeoxycholic acid (UDCA) and tauroursodeoxycholic acid (TUDCA) prevent transforming growth factor beta1 (TGF-beta1)-induced hepatocyte apoptosis by modulating the E2F-1/p53/Bax pathway. In addition, activation of glucocorticoid (GR) and mineralocorticoid receptors (MR) inhibits apoptosis in various systems. UDCA induces a ligand-independent activation of the GR, thus potentially regulating a number of targets. In this study, we investigated the role of GR and MR during TGF-beta1-induced hepatocyte apoptosis, and identified additional antiapoptotic targets for UDCA. Our results showed that in primary hepatocytes, TGF-beta1 induced 40-50% decreases in gr and mr mRNA expression (p < 0.01), together with up to 10-fold reductions in their protein levels (p < 0.01). Notably, pretreatment with UDCA resulted in a significant upregulation of nuclear steroid receptors (p < 0.05), which coincided with 2- and 3-fold increases in the level of GR and MR nuclear translocation, respectively, when compared with that of TGF-beta1 alone (p < 0.05). Similarly, TUDCA induced GR and MR nuclear translocations (p < 0.05) and markedly prevented MR protein changes associated with TGF-beta1 (p < 0.05) without affecting GR protein levels. Moreover, when interference RNA was used to inhibit GR and MR, UDCA no longer protected hepatocytes against TGF-beta1-induced apoptosis. In fact, the protective effect of UDCA in TGF-beta1-associated caspase activation decreased from 65 to <10% when GR or MR function was blocked. Finally, the TGF-beta1-induced E2F-1/Mdm-2/p53 apoptotic pathway, normally inhibited by UDCA, was not regulated by the bile acid after GR or MR silencing. These results demonstrate that UDCA protects against apoptosis through an additional pathway that involves nuclear receptors GR and MR as key factors. Further, the E2F-1/Mdm-2/p53 apoptotic pathway appears to be a prime target for UDCA-induced steroid receptor activation.
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Affiliation(s)
- Susana Solá
- Centro de Patogénese Molecular, Faculty of Pharmacy, University of Lisbon, Lisbon 1600-083, Portugal
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Yamashita T, Mimura K, Umeda F, Kobayashi K, Hashimoto T, Nawata H. Increased transendothelial permeation of albumin by high glucose concentration. Metabolism 1995; 44:739-44. [PMID: 7540248 DOI: 10.1016/0026-0495(95)90186-8] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Vascular endothelial cells, which are polyfunctional, play an important role in the pathogenesis of diabetic complications. The increase in vascular permeability, ie, regulated by vascular endothelial cells, has been reported in patients with diabetes mellitus complicated by angiopathy. To determine the role of hyperglycemia in endothelial cell permeability, we examined the effect of high concentrations of glucose on the permeability of cultured bovine aortic endothelial cells. The permeations of albumin and fluorescein-labeled dextran (FD) across endothelial cell monolayers were increased when cultured with a high concentration of glucose (400 mg/dL). This increased permeation of albumin but not FD was temperature-dependent and was partially reduced by adding 100 mumol/L ponalrestat (ICI 128,436, Statil; ICI, Cheshire, UK), which is an aldose reductase inhibitor. Stimulation or inhibition of Na,K-adenosine triphosphatase (ATPase) in bovine aortic endothelial cells failed to alter their permeability. These findings suggest that high concentrations of glucose enhance transendothelial permeability of albumin in part by activating the polyol pathway, but independently of Na,K-ATPase activity.
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Affiliation(s)
- T Yamashita
- Third Department of Internal Medicine, Faculty of Medicine, Kyushu University, Fukuoka, Japan
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Territo M, Berliner JA, Fogelman AM. Effect of monocyte migration on low density lipoprotein transport across aortic endothelial cell monolayers. J Clin Invest 1984; 74:2279-84. [PMID: 6511926 PMCID: PMC425421 DOI: 10.1172/jci111655] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Endothelial cell monolayers on polycarbonate filters present a barrier to low density lipoprotein (LDL) and albumin transport. These cells form a relatively tight monolayer as shown by measurements of electrical resistance across the monolayer (15 omega-cm2). Monocytes are able to migrate freely across the monolayers in response to chemotactic stimuli. Monocyte chemotaxis across the monolayer caused a marked increase in LDL and albumin transport across the monolayer in the direction of monocyte migration. However, transport in the opposite direction was not significantly increased. These results suggest that monocyte migration across the endothelium could lead to an increased LDL content of the intima.
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Duval D, Durant S, Homo-Delarche F. Non-genomic effects of steroids. Interactions of steroid molecules with membrane structures and functions. BIOCHIMICA ET BIOPHYSICA ACTA 1983; 737:409-42. [PMID: 6309233 DOI: 10.1016/0304-4157(83)90008-4] [Citation(s) in RCA: 207] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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10
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Riede UN, Moore GW, Sandritter W. Symbolic logic as a new method of quantitative organelle pathology. Exp Mol Pathol 1980; 33:259-82. [PMID: 7449926 DOI: 10.1016/0014-4800(80)90025-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
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11
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Avdalovic N, Weibel J, Diamond L. The effects of 5-bromodeoxyuridine on the growth and morphology of transformed rat liver cells. J Cell Physiol 1980; 104:83-96. [PMID: 7440648 DOI: 10.1002/jcp.1041040112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The effects of bromodeoxyuridine (BrdUrd) on the growth, morphology, and tumorigenicity of the spontaneously transformed rat liver cell line R72/3 were studied. These cells grow either in suspension or in a monolayer and are tumorigenic. In monolayer cultures, cells treated with low concentrations (2.5 micrograms/ml) of BrdUrd were larger, more spread out, and more firmly attached to the substratum than were untreated controls. Treated cells failed to grow in suspension or on confluent monolayers of 3T3 cells and did not form colonies in soft agar. Scanning electron microscopy revealed extensive flattening of treated cells and a dramatic reduction in the number of microvilli on the cell surface. Transmission electron microscopy showed an increase in polyribosomes and rough endoplasmic reticulum, as well as an enlargement of endoplasmic reticulum cisternae and a complete absence of the bundles of intermediate size filaments that were conspicuous in untreated cells. The persistence of these changes required the continuous presence of BrdUrd in the medium. The effects of BrdUrd were readily reversed by withdrawal of BrdUrd and were not expressed in the presence of excess thymidine.
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Williams GM, Bermudez E, San RH, Goldblatt PJ, Laspia MF. Rat hepatocyte primary cultures. IV. Maintenance in defined medium and the role of production of plasminogen activator and other proteases. IN VITRO 1978; 14:824-37. [PMID: 569118 DOI: 10.1007/bf02616152] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Primary cultures of rat hepatocytes survived well for up to 4 days in defined medium in the presence of dexamethasone but not in its absence. The loss of viability was accompanied by a loss of ultrastructural features characteristic of hepatocytes. The cultures began producing plasminogen activator and a neutral protease after 24 hr in culture. Dexamethasone inhibited the production of both of these substances. The deterioration of the cultures appeared not to be related to plasminogen activator, but prolongation of survival by a variety of protease inhibitors suggested that the neutral protease might contribute to deterioration.
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Berliner JA, Bennett K, de Vellis J. Effect of hydrocortisone on cell morphology in C6 cells. J Cell Physiol 1978; 94:321-33. [PMID: 563867 DOI: 10.1002/jcp.1040940310] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Hydrocortisone has been found to induce cell spreading in rat glial C6 cells by 24 hours after its addition. This spreading phenomenon is correlated with an increase in the fraction of the peripheral cytoplasm occupied by microfilaments. Cytochalasin B causes disorganization of microfilaments in the peripheral cytoplasm of the cells. Additionally, it also prevents cell spreading in response to hormonal stimulation. High levels of calcium prevent recovery of normal microfilament organization and cell spreading following removal of cytochalasin B, but have no effect on normal microfilament organization alone. Additionally both the hydrocortisone induced spreading of C6 cells and increases in peripheral microfilaments are shown to be dependent on RNA ans protein synthesis. The levels of protein co-electrophoresing with actin are not effected by hydrocortisone.
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Volman H. A morphologic and morphometric study of the mitochondria in several hepatoma cell lines and in isolated hepatocytes. VIRCHOWS ARCHIV. B, CELL PATHOLOGY 1978; 26:249-59. [PMID: 205039 DOI: 10.1007/bf02889552] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Some characteristics of the mitochondria of hepatocytes and of three hepatoma cell lines have been compared. By means of stereologic analysis of electron micrographs of cross-sections through cells the volume of mitochondria per unit volume of cell cytoplasm and the surface areas of the mitochondrial envelope and cristae membranes have been measured. The relative mitochondrial volume in the cytoplasm decreases with increasing growth rate but the surface area of outer and cristae membranes per unit volume of mitochondria is not altered. The internal organization of hepatoma mitochondria, however, differs distinctly from that of normal liver mitochondria as evident from electron micrographs; the hepatoma cells contain mitochondria in which parallel cristae appear to cross the whole mitochondrial profile unlike the irregular, short cristae seen in normal liver mitochondria. Furthermore, in the fast-growing hepatoma cells the mitochondrial matrix appears less dense than in the hepatocyte. Hepatoma cells contain less organized rough endoplasmic reticulum than normal liver cells and the spatial relationship of the mitochondria to the rough cisternae, seen in the hepatocyte, is absent in the fast-growing hepatoma cell lines. It is concluded that hepatoma cells have fewer mitochondria than normal liver cells, but that the organelles have a normal content of inner membranes.
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Glucocorticoid action on rat thymic lymphocytes. Experiments utilizing adenosine to support cellular metabolism lead to a reassessment of catabolic hormone actions. J Biol Chem 1976. [DOI: 10.1016/s0021-9258(17)32849-1] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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Berliner JA, Gerschenson LE. Sex steroid induced morphological changes in primary uterine cell cultures. JOURNAL OF STEROID BIOCHEMISTRY 1976; 7:153-8. [PMID: 933519 DOI: 10.1016/0022-4731(76)90196-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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Reith A, Barnard T, Rohr HP. Stereology of cellular reaction patterns. CRC CRITICAL REVIEWS IN TOXICOLOGY 1976; 4:219-69. [PMID: 57027 DOI: 10.1080/10408447609164015] [Citation(s) in RCA: 43] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Berliner JA, Gerschenson LE. The effects of a glucocorticoid on the cell surface of RLC-GAI cells. J Cell Physiol 1975; 86:523-31. [PMID: 1202032 DOI: 10.1002/jcp.1040860309] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The purpose of these studies was to examine the effects of a synthetic glucocorticoid, dexamethasone sodium phosphate, on the cell surface of an epithelial cell line, RLC-GAI, and to investigate the mechanism of these effects. Within hours after addition of dexamethasone sodium phosphate to the cultures, the cells begin to spread going from a more bipolar to a more epithelioid form; this change is maximal by 24 hours. In the spread cells the density of surface microvilli, as visualized in the scanning electron microscope, is considerably reduced. The changes in cell surface and shape elicited by the glucocorticoid are blocked by actinomycin D but not by hydroxyurea. Cell spreading is probably related to the configuration of cell microfilaments since these are increased in numbers in the presence of the hormone and spreading is inhibited by cytochalasin B. An important role of microfilaments in the general mechanism of action of glucocorticoids is suggested.
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