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Regulation of Tight Junctions for Therapeutic Advantages. CANCER METASTASIS - BIOLOGY AND TREATMENT 2013. [DOI: 10.1007/978-94-007-6028-8_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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Yuki T, Komiya A, Kusaka A, Kuze T, Sugiyama Y, Inoue S. Impaired tight junctions obstruct stratum corneum formation by altering polar lipid and profilaggrin processing. J Dermatol Sci 2012; 69:148-58. [PMID: 23273645 DOI: 10.1016/j.jdermsci.2012.11.595] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 11/21/2012] [Accepted: 11/30/2012] [Indexed: 12/31/2022]
Abstract
BACKGROUND The stratum corneum (SC) is a well-known structure responsible for the cutaneous barrier. Tight junctions (TJs) function as a paracellular barrier beneath the SC and are involved in the cutaneous barrier. It remains unclear how TJs are involved in the cutaneous barrier. OBJECTIVE In order to clarify the role of TJs in the cutaneous barrier, we investigated skin equivalent models with disrupted TJ barriers focusing on the SC. METHODS Skin equivalents with disrupted TJ barriers were established using GST-C-CPE, a peptide with specific inhibitory action against specific claudins. The changes of the SC barrier in the skin equivalents with disrupted TJ barriers were investigated and compared with control skin equivalents. RESULTS An outside-to-inside skin barrier assay revealed a defective SC barrier in skin equivalents with disrupted TJ barriers. A detailed examination of the SC revealed an increase in the pH of the SC in the skin equivalent with disrupted TJ barriers. An electron microscopy showed the failure of lamellar structures to mature and the failure of keratohyalin granules to degrade in the skin equivalents with disrupted TJ barriers. A thin layer chromatography analysis showed an increase in polar lipids and a decrease in non-polar lipids. A western blot analysis showed an increase in filaggrin dimer and trimer and a decrease in filaggrin monomer. CONCLUSION We found that disrupted TJs obstructed the SC formation responsible for the cutaneous barrier. Our study indicates the possibility that impaired TJ barriers affect polar lipids and profilaggrin processing by disturbing the pH condition of the SC.
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Affiliation(s)
- Takuo Yuki
- Innovative Beauty Science Laboratory, Kanebo Cosmetics Inc., Kotobuki-cho, Odawara, Kanagawa, Japan.
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Schulzke JD, Günzel D, John LJ, Fromm M. Perspectives on tight junction research. Ann N Y Acad Sci 2012; 1257:1-19. [PMID: 22671584 DOI: 10.1111/j.1749-6632.2012.06485.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The tight junction connects neighboring epithelial or endothelial cells. As a general function, it seals the paracellular pathway and thus prevents back-leakage of just transported solutes and water. However, not all tight junctions are merely tight: some tight junction proteins build their own transport pathways by forming channels selective for small cations, anions, or water. Two families of tight junction proteins have been identified, claudins (27 members in mammals) and tight junction-associated MARVEL proteins ((TAMPs) occludin, tricellulin, and MarvelD3); an additional, structurally different, junction protein is junction adhesion molecule (JAM). Besides classification by genetic or molecular kinship, classification of tight junction proteins has been suggested according to permeability attributes. Recent studies describe specific cis and trans interactions and manifold physiologic regulations of claudins and TAMPs. In many inflammatory and infectious diseases they are found to be altered, for example, causing adversely increased permeability. Currently, attempts are being made to alter the paracellular barrier for therapeutic interventions or for transiently facilitating drug uptake. This overview concludes with a list of open questions and future topics in tight junction research.
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Affiliation(s)
- Jörg-Dieter Schulzke
- Department of Gastroenterology, Infectious Diseases, and Rheumatology, Division of Nutritional Medicine, Charité, Universitätsmedizin Berlin, Germany.
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Kirschner N, Brandner JM. Barriers and more: functions of tight junction proteins in the skin. Ann N Y Acad Sci 2012; 1257:158-66. [PMID: 22671602 DOI: 10.1111/j.1749-6632.2012.06554.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Although the existence of tight junction (TJ) structures (or a secondary epidermal barrier) was postulated for a long time, the first description of TJ proteins in the epidermis (occludin, ZO-1, and ZO-2) was only fairly recent. Since then, a wealth of new insights concerning TJs and TJ proteins, including their functional role in the skin, have been gathered. Of special interest is that the epidermis as a multilayered epithelium exhibits a very complex localization pattern of TJ proteins, which results in different compositions of TJ protein complexes in different layers. In this review, we summarize our current knowledge about the role of TJ proteins in the epidermis in barrier function, cell polarity, vesicle trafficking, differentiation, and proliferation. We hypothesize that TJ proteins fulfill TJ structure-dependent and structure-independent functions and that the specific function of a TJ protein may depend on the epidermal layer where it is expressed.
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Affiliation(s)
- Nina Kirschner
- Department of Dermatology and Venerology, University Hospital Hamburg-Eppendorf, Germany
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Celli A, Zhai Y, Jiang YJ, Crumrine D, Elias PM, Feingold KR, Mauro TM. Tight junction properties change during epidermis development. Exp Dermatol 2012; 21:798-801. [PMID: 22882565 DOI: 10.1111/j.1600-0625.2012.01573.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/01/2012] [Indexed: 12/01/2022]
Abstract
In terrestrial animals, the epidermal barrier transitions from covering an organism suspended in a liquid environment in utero, to protecting a terrestrial animal postnatally from air and environmental exposure. Tight junctions (TJ) are essential for establishing the epidermal permeability barrier during embryonic development and modulate normal epidermal development and barrier functions postnatally. We now report that TJ function, as well as claudin-1 and occludin expression, change in parallel during late epidermal development. Specifically, TJ block the paracellular movement of Lanthanum (La(3+)) early in rat in vivo prenatal epidermal development, at gestational days 18-19, with concurrent upregulation of claudin-1 and occludin. TJ then become more permeable to ions and water as the fetus approaches parturition, concomitant with development of the lipid epidermal permeability barrier, at days 20-21. This sequence is recapitulated in cultured human epidermal equivalents (HEE), as assessed both by ultrastructural studies comparing permeation of large and small molecules and by the standard electrophysiologic parameter of resistance (R), suggesting further that this pattern of development is intrinsic to mammalian epidermal development. These findings demonstrate that the role of TJ changes during epidermal development, and further suggest that the TJ-based and lipid-based epidermal permeability barriers are interdependent.
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Raiko L, Siljamäki E, Mahoney MG, Putaala H, Suominen E, Peltonen J, Peltonen S. Hailey-Hailey disease and tight junctions: Claudins 1 and 4 are regulated by ATP2C1 gene encoding Ca(2+) /Mn(2+) ATPase SPCA1 in cultured keratinocytes. Exp Dermatol 2012; 21:586-91. [PMID: 22639968 PMCID: PMC3879075 DOI: 10.1111/j.1600-0625.2012.01520.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/26/2012] [Indexed: 11/29/2022]
Abstract
Mutations in the ATP2C1 gene encoding Ca(2+) /Mn(2+) ATPase SPCA1 cause Hailey-Hailey disease (HHD, OMIM 16960). HHD is characterized by epidermal acantholysis. We attempted to model HHD using normal keratinocytes, in which the SPCA1 mRNA was down-regulated with the small inhibitory RNA (siRNA) method. SiRNA inhibition significantly down-regulated the SPCA1 mRNA, as demonstrated by qPCR, and decreased the SPCA1 protein beyond detectable level, as shown by Western analysis. The expression of selected desmosomal, adherens and tight junction (TJ) proteins was then studied in the SPCA1-deficient and control keratinocytes cultured in low (0.06 mm) or high (1.2 mm) calcium concentration. The mRNA and protein levels of most TJ components were up-regulated in non-treated control keratinocyte cultures upon switch from low to high calcium concentration. In contrast, SPCA1-deficient keratinocytes displayed high levels of TJ proteins claudins 1 and 4 even in low calcium. ZO-1 did not, however, follow similar expression patterns. Protein levels of occludin, beta-catenin, E-cadherin, desmoplakin, desmogleins 1-3, desmocollin 2/desmocollin 3 and plakoglobin did not show marked changes in SPCA1-deficient keratinocytes. Indirect immunofluorescence labelling revealed delayed translocation of desmoplakin and desmoglein 3 in desmosomes and increased intracellular pools of TJ and desmosomal components in SPCA1-inhibited keratinocytes. The results show that SPCA1 regulates the levels of claudins 1 and 4, but does not affect desmosomal protein levels, indicating that TJ proteins are differently regulated. The results also suggest a potential role for claudins in HHD.
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Affiliation(s)
- Laura Raiko
- Department of Dermatology, University of Turku and Turku University Hospital, Turku, Finland
- Department of Cell Biology and Anatomy, University of Turku, Turku Finland
| | - Elina Siljamäki
- MediCity Research Laboratory, University of Turku, Turku, Finland
| | - Mỹ G. Mahoney
- Department of Dermatology and Cutaneous Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Heli Putaala
- DuPont Nutrition & Health, Active Nutrition, 02460 Kantvik, Finland
| | - Erkki Suominen
- Department of Surgery, Turku University Hospital, Turku, Finland
| | - Juha Peltonen
- Department of Cell Biology and Anatomy, University of Turku, Turku Finland
| | - Sirkku Peltonen
- Department of Dermatology, University of Turku and Turku University Hospital, Turku, Finland
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Kirschner N, Rosenthal R, Günzel D, Moll I, Brandner JM. Tight junctions and differentiation--a chicken or the egg question? Exp Dermatol 2012; 21:171-5. [PMID: 22379962 DOI: 10.1111/j.1600-0625.2011.01431.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Skin barrier function is indispensable to prevent the uncontrolled loss of water and solutes and to protect the body from external assaults. To fulfil this function, keratinocytes undergo a complex pathway of differentiation that terminates in the formation of the stratum corneum. Additionally, tight junctions (TJs), which are cell-cell junctions localized in the stratum granulosum, are involved in the barrier function of the skin. Important biological and clinical roles of TJs are strongly suggested by altered TJ protein levels and distribution in skin diseases like psoriasis, ichthyosis and atopic dermatitis. Because these skin diseases show alterations in differentiation and TJs, it was suggested that changes in TJs might simply be a consequence of altered differentiation. However, in this viewpoint, we like to argue that the situation is not as simple and depends on the specific microenvironment. We discuss three hypotheses regarding the interplay between TJs/TJ proteins and differentiation: (1) TJs/TJ proteins are influenced by differentiation, (2) differentiation is influenced by TJs/TJ proteins, and (3) TJs/TJ proteins and differentiation are independent of each other. In addition, the concept is introduced that both processes are going on at the same time, which means that while one specific TJ protein/barrier component might be influenced by differentiation, the other may influence differentiation.
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Affiliation(s)
- Nina Kirschner
- Department of Dermatology and Venerology, University Hospital Hamburg-Eppendorf, Germany Institute of Clinical Physiology, Charité, Campus Benjamin Franklin, Berlin, Germany
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Kasparek P, Krenek P, Buryova H, Suchanova S, Beck IM, Sedlacek R. Transgenic mouse model expressing tdTomato under involucrin promoter as a tool for analysis of epidermal differentiation and wound healing. Transgenic Res 2012; 21:683-9. [PMID: 22020981 DOI: 10.1007/s11248-011-9567-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Accepted: 08/04/2011] [Indexed: 11/26/2022]
Abstract
The epidermis is a stratified tissue composed of different keratinocyte layers that create a barrier protecting the body from external influences, pathogens, and dehydration. The barrier function is mainly achieved by its outermost layer, the stratum corneum. To create a mouse model to study pathophysiological processes in the outermost layers of the epidermis in vivo and in vitro we prepared a construct containing red fluorescent td-Tomato reporter sequence under the control of involucrin promoter and its first intron. Transgenic mice were generated by pronuclear injection and the expression and regulation of the transgene was determined by in vivo imaging and fluorescent microscopy. The promoter targeted the transgene efficiently and specifically into the outermost epidermal layers although weak expression was also found in epithelia of tongue and bladder. The regulation of expression in the epidermis, i.e. fluorescence intensity of the reporter, could be easily followed during wound healing and dermatitis. Thus, these transgenic mice carrying the tdTomato reporter could be used as a valuable tool to study impact of various genes dysregulating the epidermal barrier and to follow effects of therapeutic agents for treatment of skin diseases in vivo.
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Affiliation(s)
- Petr Kasparek
- Department of Transgenic Models of Diseases, Institute of Molecular Genetics of the ASCR, v.v.i., Vídeňská 1083, 14220 Prague 4, Czech Republic
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Yao PL, Lin YC, Richburg JH. Mono-(2-ethylhexyl) phthalate (MEHP) promotes invasion and migration of human testicular embryonal carcinoma cells. Biol Reprod 2012; 86:160, 1-10. [PMID: 22321834 DOI: 10.1095/biolreprod.111.097295] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Testicular dysgenesis syndrome refers to a collection of diseases in men, including testicular cancer, that arise as a result of abnormal testicular development. Phthalates are a class of chemicals used widely in the production of plastic products and other consumer goods. Unfortunately, phthalate exposure has been linked to reproductive dysfunction and has been shown to adversely affect normal germ cell development. In this study, we show that mono-(2-ethylhexyl) phthalate (MEHP) induces matrix metalloproteinase 2 (MMP2) expression in testicular embryonal carcinoma NT2/D1 cells but has no significant effect on MMP9 expression. NT2/D1 cells also have higher levels of MYC expression following MEHP treatment. It is widely recognized that activation of MMP2 and MYC is tightly associated with tumor metastasis and tumor progression. Gelatin zymographic analysis indicates that MEHP strongly activates MMP2 in NT2/D1 cells. Addition of the MMP2-specific inhibitor SB-3CT inhibited MEHP-enhanced cell invasion and migration, demonstrating that MMP2 plays a functional role in promoting testicular embryonal carcinoma progression in response to MEHP exposure. Furthermore, we investigated genome-wide gene expression profiles of NT2/D1 cells following MEHP exposure at 0, 3, and 24 h. Microarray analysis and semiquantitative RT-PCR revealed that MEHP exposure primarily influenced genes in cell adhesion and transcription in NT2/D1 cells. Gap junction protein-alpha 1, vinculin, and inhibitor of DNA-binding protein-1 were significantly down-regulated by MEHP treatment, while claudin-6 and beta 1-catenin expression levels were up-regulated. This study provides insight into mechanisms that may account for modulating testicular cancer progression following phthalate exposure.
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Affiliation(s)
- Pei-Li Yao
- Center for Molecular and Cellular Toxicology, Division of Pharmacology and Toxicology, College of Pharmacy, The University of Texas at Austin, Austin, Texas, USA.
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Wu X, Peppi M, Vengalil MJ, Maheras KJ, Southwood CM, Bradley M, Gow A. Transgene-mediated rescue of spermatogenesis in Cldn11-null mice. Biol Reprod 2012; 86:139, 1-11. [PMID: 22378758 DOI: 10.1095/biolreprod.111.096230] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Claudins comprise a large family of tight junction (TJ) proteins that are often expressed broadly during development and in adult tissues and constitute the physical barriers that occlude the paracellular space in polarized epithelia. In mouse testis, the integrity of TJs is critical to normal spermatogenesis and is dependent on CLDN11 expression. In the current study, we have generated multiple transgenic mouse lines in which steady-state levels of transgene-derived Cldn11 mRNA are up to fourfold greater than endogenous gene expression. Spermatogenesis in all founder mice harboring two copies of the endogenous Cldn11 gene is normal. These animals breed well, indicating that transgene overexpression, at least at the level of mRNA, is well tolerated by Sertoli cells. In addition, we demonstrate that the promoter/enhancer of the transgene, comprising 5 kb of genomic sequence upstream of exon 1 of the mouse Cldn11 gene, is sufficient to rescue azoospermia in Cldn11-null mice. Finally, using transient transgenic mice, we narrow the location of Sertoli cell-specific cis regulatory elements to a 2-kb region upstream of the Cldn11 transcription start site. Together, these data provide essential information for further investigation of the biological regulation of CLDN11 TJs in the testis.
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Affiliation(s)
- Xin Wu
- Center for Molecular Medicine and Genetics, Wayne State University School of Medicine, Detroit, Michigan 48201, USA
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63
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Baroni A, Buommino E, De Gregorio V, Ruocco E, Ruocco V, Wolf R. Structure and function of the epidermis related to barrier properties. Clin Dermatol 2012; 30:257-62. [DOI: 10.1016/j.clindermatol.2011.08.007] [Citation(s) in RCA: 282] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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Kypriotou M, Huber M, Hohl D. The human epidermal differentiation complex: cornified envelope precursors, S100 proteins and the 'fused genes' family. Exp Dermatol 2012; 21:643-9. [PMID: 22507538 DOI: 10.1111/j.1600-0625.2012.01472.x] [Citation(s) in RCA: 230] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The skin is essential for survival and protects our body against biological attacks, physical stress, chemical injury, water loss, ultraviolet radiation and immunological impairment. The epidermal barrier constitutes the primordial frontline of this defense established during terminal differentiation. During this complex process proliferating basal keratinocytes become suprabasally mitotically inactive and move through four epidermal layers (basal, spinous, granular and layer, stratum corneum) constantly adapting to the needs of the respective cell layer. As a result, squamous keratinocytes contain polymerized keratin intermediate filament bundles and a water-retaining matrix surrounded by the cross-linked cornified cell envelope (CE) with ceramide lipids attached on the outer surface. These cells are concomitantly insulated by intercellular lipid lamellae and hold together by corneodesmosmes. Many proteins essential for epidermal differentiation are encoded by genes clustered on chromosomal human region 1q21. These genes constitute the 'epidermal differentiation complex' (EDC), which is divided on the basis of common gene and protein structures, in three gene families: (i) CE precursors, (ii) S100A and (iii) S100 fused genes. EDC protein expression is regulated in a gene and tissue-specific manner by a pool of transcription factors. Among them, Klf4, Grhl3 and Arnt are essential, and their deletion in mice is lethal. The importance of the EDC is further reflected by human diseases: FLG mutations are the strongest risk factor for atopic dermatitis (AD) and for AD-associated asthma, and faulty CE formation caused by TG1 deficiency causes life-threatening lamellar ichthyosis. Here, we review the EDC genes and the progress in this field.
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Affiliation(s)
- Magdalini Kypriotou
- Laboratory of Cutaneous Biology, Service of Dermatology and Venereology, Beaumont Hospital CHUV, Lausanne, Switzerland
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Abstract
The intermediate filament keratin 15 (K15) is present in variable amounts in various stratified epithelia, but has also been reported to be a stem cell marker in the hair follicle. Using peptide specific antibodies, we evaluated the temporal and spatial distribution pattern of K15 expression/localization during normal epidermal development and initiation of hair follicle formation, and in the injured mature epidermis (e.g., during acute injury and repair and in tumorigenesis). During development, K15 expression is first localized to a subset of epidermal basal cells and the overlying periderm at E12.5, but its expression is seen throughout the basal layer by E15.5 and beyond. In hair follicle morphogenesis, initial peg formation occurs in a K15-null area at E14.5 and as peg elongation proceeds through to the mature hair follicle, K15 expression follows the leading edge with positive cells restricted to the outer root sheath. In an epidermal injury model, K15 is first up-regulated and associated with both the basal and suprabasal layers of the interfollicular epidermis then expression becomes sporadic and down-regulated before a basal layer-specific association is re-established in the repaired epidermis. During tumorigenesis, K15 is first mis-expressed, and is ultimately down-regulated. Our data suggest that K15 protein expression may reflect not only expression in a stem or progenitor cell subpopulation, but also reflects the activity and responsiveness of basal-like cells to loss of homeostasis of the epidermal differentiation program. Thus, the data suggest caution in using K15 alone to delineate epidermal stem cells, and underscore the need for further investigation of K15 and other markers in epidermal cell subpopulations.
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Affiliation(s)
- Tammy-Claire Troy
- Regenerative Medicine Program, Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, 501 Smyth Road-CCW5226, Ottawa, Ontario K1Y 8L6, Canada.
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Kubo A, Nagao K, Amagai M. Epidermal barrier dysfunction and cutaneous sensitization in atopic diseases. J Clin Invest 2012; 122:440-7. [PMID: 22293182 DOI: 10.1172/jci57416] [Citation(s) in RCA: 252] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Classic atopic dermatitis is complicated by asthma, allergic rhinitis, and food allergies, cumulatively referred to as atopic diseases. Recent discoveries of mutations in the filaggrin gene as predisposing factors for atopic diseases have refocused investigators' attention on epidermal barrier dysfunction as a causative mechanism. The skin's barrier function has three elements: the stratum corneum (air-liquid barrier), tight junctions (liquid-liquid barrier), and the Langerhans cell network (immunological barrier). Clarification of the molecular events underpinning epidermal barrier function and dysfunction should lead to a better understanding of the pathophysiological mechanisms of atopic diseases.
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Affiliation(s)
- Akiharu Kubo
- Department of Dermatology, Keio University School of Medicine, Shinanomachi 35, Shinjuku, Tokyo 160-8582, Japan
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Abstract
Claudins are tight junction proteins with claudin-6 (CLDN6) expression mostly restricted to embryonic and fetal life. Previously reported gene expression microarray analysis showed an increased level of CLDN6 in atypical teratoid rhabdoid tumors (AT/RT) compared with other central nervous system (CNS) tumors and sarcomas. However, there exist conflicting data on expression of CLDN6 as assessed by immunohistochemistry in CNS tumors. We established membranous staining as a specific and reproducible method for evaluating CLDN6 expression based on fetal and adolescent controls. We then evaluated a large group (257) of pediatric tumors using tissue microarrays, including: 47 malignant rhabdoid tumors (MRTs), (31 AT/RTs and 16 non-CNS MRTs); 67 small, round, blue cell tumors (10 Wilms tumors, 10 embryonal rhabdomyosarcomas, 10 neuroblastomas (NBs), 10 synovial sarcomas (SSs), 9 hepatoblastomas (HBs), 9 alveolar rhabdomyosarcomas, and 9 Ewings sarcomas); and 143 CNS tumors (24 medulloblastomas, 21 pilocytic astrocytomas, 14 astrocytomas grade II/III, 13 gangliogliomas, 12 glioblastomas, 12 ependymal tumors, 11 choroid plexus tumors, 10 meningiomas, 8 dysembryoplastic neuroepithelial tumors, 8 oligodendrogliomas, 4 craniopharyngiomas, 2 germinomas, 2 primitive neuroectodermal tumors (PNET), and 2 central neurocytomas). CLDN6 expression was seen in 12 of 31 (39%) AT/RTs, 7 of 16 (44%) non-CNS MRTs, 5 of 10 (50%) Wilms tumors, 1 of 9 (11%) HBs, 2 of 2 (100%) germinomas, 1 of 2 (50%) CNS PNETs, 1 of 24 (4%) medulloblastomas, and 1 of 10 (10%) meningiomas. Ten of 11 (91%) choroid plexus tumors showed apical staining but no concentric membranous staining. Although CLDN6 is expressed in both AT/RTs and MRTs, it is not a specific biomarker as it is expressed in a variety of other pediatric CNS and soft tissue tumors.
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Abstract
For at least half a century, noninvasive techniques have been available to quantify skin barrier function, and these have shown that a number of human skin conditions and disorders are associated with defects in skin permeability. In the past decade, several genes responsible for skin barrier defects observed in both monogenetic and complex polygenic disorders have been elucidated and functionally characterized. This has led to an explosion of work in the past 6 years that has identified pathways connecting epidermal barrier disruption and antigen uptake, as well as the quality and/or magnitude of the antigen-specific adaptive immune response. This review will introduce the notion that diseases arise from the dynamic crosstalk that occurs between skin barrier and the immune system using atopic dermatitis or eczema as the disease prototype. Nevertheless, the concepts put forth are highly relevant to a number of antigen-driven disorders for which skin barrier is at least transiently compromised, such as psoriasis, allergic contact dermatitis, and blistering disorders.
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Assimakopoulos SF, Papageorgiou I, Charonis A. Enterocytes’ tight junctions: From molecules to diseases. World J Gastrointest Pathophysiol 2011; 2:123-37. [PMID: 22184542 PMCID: PMC3241743 DOI: 10.4291/wjgp.v2.i6.123] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2011] [Revised: 08/26/2011] [Accepted: 10/31/2011] [Indexed: 02/06/2023] Open
Abstract
Tight junctions (TJs) are structures between cells where cells appear in the closest possible contact. They are responsible for sealing compartments when epithelial sheets are generated. They regulate the permeability of ions, (macro) molecules and cells via the paracellular pathway. Their structure at the electron microscopic level has been well known since the 1970s; however, only recently has their macromolecular composition been revealed. This review first examines the major macromolecular components of the TJs (occludin, claudins, junctional adhesion molecule and tricellulin) and then the associated macromolecules at the intracellular plaque [zonula occludens (ZO)-1, ZO-2, ZO-3, AF-6, cingulin, 7H6]. Emphasis is given to their interactions in order to begin to understand the mode of assembly of TJs. The functional significance of TJs is detailed and several mechanisms and factors involved are discussed briefly. Emphasis is given to the role of intestinal TJs and the alterations observed or speculated in diverse disease states. Specifically, intestinal TJs may exert a pathogenetic role in intestinal (inflammatory bowel disease, celiac disease) and extraintestinal diseases (diabetes type 1, food allergies, autoimmune diseases). Additionally, intestinal TJs may be secondarily disrupted during the course of diverse diseases, subsequently allowing the bacterial translocation phenomenon and promoting the systemic inflammatory response, which is often associated with clinical deterioration. The major questions in the field are highlighted.
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Haddad N, Andalousi JE, Khairallah H, Yu M, Ryan AK, Gupta IR. The tight junction protein claudin-3 shows conserved expression in the nephric duct and ureteric bud and promotes tubulogenesis in vitro. Am J Physiol Renal Physiol 2011; 301:F1057-65. [DOI: 10.1152/ajprenal.00497.2010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
The claudin family of proteins is required for the formation of tight junctions that are contact points between epithelial cells. Although little is known of the cellular events by which epithelial cells of the ureteric bud form tubules and branch, tubule formation is critical for kidney development. We hypothesize that if claudin-3 (Cldn3) is expressed within tight junctions of the ureteric bud, this will affect ureteric bud cell shape and tubule formation. Using transmission electron microscopy, we identified tight junctions within epithelial cells of the ureteric bud. Whole mount in situ hybridization and immunoassays were performed in the mouse and chick and demonstrated that Cldn3 transcript and protein were expressed in the nephric duct, the ureteric bud, and its derivatives at critical time points during tubule formation and branching. Mouse inner medullary collecting duct cells (mIMCD-3) form tubules when seeded in a type I collagen matrix and were found to coexpress CLDN3 and the tight junction marker zonula occludens-1 in the cell membrane. When these cells were stably transfected with Cldn3 fused to the enhanced green fluorescent protein reporter, multiple clones showed a significant increase in tubule formation compared with controls ( P < 0.05) due in part to an increase in cell proliferation ( P < 0.01). Cldn3 may therefore promote tubule formation and expansion of the ureteric bud epithelium.
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Affiliation(s)
| | - Jasmine El Andalousi
- Pediatrics, McGill University, and The Research Institute of McGill University Health Centre, Montreal Children's Hospital, Montréal, Québec, Canada
| | | | - Melissa Yu
- Pediatrics, McGill University, and The Research Institute of McGill University Health Centre, Montreal Children's Hospital, Montréal, Québec, Canada
| | - Aimee K. Ryan
- Pediatrics, McGill University, and The Research Institute of McGill University Health Centre, Montreal Children's Hospital, Montréal, Québec, Canada
| | - Indra R. Gupta
- Pediatrics, McGill University, and The Research Institute of McGill University Health Centre, Montreal Children's Hospital, Montréal, Québec, Canada
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Fehrenschild D, Galli U, Breiden B, Bloch W, Schettina P, Brodesser S, Michels C, Günschmann C, Sandhoff K, Niessen CM, Niemann C. TCF/Lef1-mediated control of lipid metabolism regulates skin barrier function. J Invest Dermatol 2011; 132:337-45. [PMID: 21938009 DOI: 10.1038/jid.2011.301] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Defects in the function of the skin barrier are associated with a wide variety of skin diseases, many of which are not well characterized at the molecular level. Using Lef1 (lymphoid enhancer-binding factor 1) dominant-negative mutant mice, we demonstrate here that altered epidermal TCF (T cell factor)/Lef1 signaling results in severe impairment of the stratum corneum skin barrier and early postnatal death. Barrier defects were accompanied by major changes in lipid composition and ultrastructural abnormalities in assembly and extrusion of lipid lamellae of the interfollicular epidermis, as well as abnormal processing of profilaggrin. In contrast, tight-junction formation and stratified organization of the interfollicular epidermis was not obviously disturbed in Lef1 mutant mice. Molecular analysis revealed that TCF/Lef1 signaling regulates expression of lipid-modifying enzymes, such as Elovl3 and stearoyl coenzyme A desaturase 1 (SCD1), which are key regulators of barrier function. Promoter analysis and chromatin immunoprecipitation experiments indeed showed that SCD1 is a direct target of Lef1. Together, our data demonstrate that functional TCF/Lef1 signaling governs important aspects of epidermal differentiation and lipid metabolism, thereby regulating skin barrier function.
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Affiliation(s)
- Dagmar Fehrenschild
- Center for Molecular Medicine Cologne (CMMC), University of Cologne, Cologne, Germany
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72
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Overgaard CE, Daugherty BL, Mitchell LA, Koval M. Claudins: control of barrier function and regulation in response to oxidant stress. Antioxid Redox Signal 2011; 15:1179-93. [PMID: 21275791 PMCID: PMC3144428 DOI: 10.1089/ars.2011.3893] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Claudins are a family of nearly two dozen transmembrane proteins that are a key part of the tight junction barrier that regulates solute movement across polarized epithelia. Claudin family members interact with each other, as well as with other transmembrane tight junction proteins (such as occludin) and cytosolic scaffolding proteins (such as zonula occludens-1 (ZO-1)). Although the interplay between all of these different classes of proteins is critical for tight junction formation and function, claudin family proteins are directly responsible for forming the equivalent of paracellular ion selective channels (or pores) with specific permeability and thus are essential for barrier function. In this review, we summarize current progress in identifying structural elements of claudins that regulate their transport, assembly, and function. The effects of oxidant stress on claudins are also examined, with particular emphasis on lung epithelial barrier function and oxidant stress induced by chronic alcohol abuse.
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Affiliation(s)
- Christian E Overgaard
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University School of Medicine, Atlanta, GA 30322, USA
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73
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Deconstructing the skin: cytoarchitectural determinants of epidermal morphogenesis. Nat Rev Mol Cell Biol 2011; 12:565-80. [PMID: 21860392 DOI: 10.1038/nrm3175] [Citation(s) in RCA: 351] [Impact Index Per Article: 25.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
To provide a stable environmental barrier, the epidermis requires an integrated network of cytoskeletal elements and cellular junctions. Nevertheless, the epidermis ranks among the body's most dynamic tissues, continually regenerating itself and responding to cutaneous insults. As keratinocytes journey from the basal compartment towards the cornified layers, they completely reorganize their adhesive junctions and cytoskeleton. These architectural components are more than just rivets and scaffolds - they are active participants in epidermal morphogenesis that regulate epidermal polarization, signalling and barrier formation.
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74
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Turksen K, Troy TC. Junctions gone bad: Claudins and loss of the barrier in cancer. Biochim Biophys Acta Rev Cancer 2011; 1816:73-9. [DOI: 10.1016/j.bbcan.2011.04.001] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 04/05/2011] [Accepted: 04/08/2011] [Indexed: 12/13/2022]
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Lin HY, Kao CH, Lin KMC, Kaartinen V, Yang LT. Notch signaling regulates late-stage epidermal differentiation and maintains postnatal hair cycle homeostasis. PLoS One 2011; 6:e15842. [PMID: 21267458 PMCID: PMC3022660 DOI: 10.1371/journal.pone.0015842] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Accepted: 11/25/2010] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Notch signaling involves ligand-receptor interactions through direct cell-cell contact. Multiple Notch receptors and ligands are expressed in the epidermis and hair follicles during embryonic development and the adult stage. Although Notch signaling plays an important role in regulating differentiation of the epidermis and hair follicles, it remains unclear how Notch signaling participates in late-stage epidermal differentiation and postnatal hair cycle homeostasis. METHODOLOGY AND PRINCIPAL FINDINGS We applied Cre/loxP system to generate conditional gene targeted mice that allow inactivation of critical components of Notch signaling pathway in the skin. Rbpj, the core component of all four Notch receptors, and Pofut1, an essential factor for ligand-receptor interactions, were inactivated in hair follicle lineages and suprabasal layer of the epidermis using the Tgfb3-Cre mouse line. Rbpj conditional inactivation resulted in granular parakeratosis and reactive epidermal hyperplasia. Pofut1 conditional inactivation led to ultrastructural abnormalities in the granular layer and altered filaggrin processing in the epidermis, suggesting a perturbation of the granular layer differentiation. Disruption of Pofut1 in hair follicle lineages resulted in aberrant telogen morphology, a decrease of bulge stem cell markers, and a concomitant increase of K14-positive keratinocytes in the isthmus of mutant hair follicles. Pofut1-deficent hair follicles displayed a delay in anagen re-entry and dysregulation of proliferation and apoptosis during the hair cycle transition. Moreover, increased DNA double stand breaks were detected in Pofut1-deficent hair follicles, and real time PCR analyses on bulge keratinocytes isolated by FACS revealed an induction of DNA damage response and a paucity of DNA repair machinery in mutant bulge keratinocytes. SIGNIFICANCE our data reveal a role for Notch signaling in regulating late-stage epidermal differentiation. Notch signaling is required for postnatal hair cycle homeostasis by maintaining proper proliferation and differentiation of hair follicle stem cells.
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Affiliation(s)
- Hsien-Yi Lin
- Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli County, Taiwan, Republic of China
| | - Cheng-Heng Kao
- Center of General Education, Chang Gung University, Tao-Yuan, Taiwan, Republic of China
| | - Kurt Ming-Chao Lin
- Division of Medical Engineering, National Health Research Institutes, Miaoli County, Taiwan, Republic of China
| | - Vesa Kaartinen
- Department of Biologic and Materials Sciences, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Liang-Tung Yang
- Institute of Cellular and System Medicine, National Health Research Institutes, Miaoli County, Taiwan, Republic of China
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77
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Abstract
Tight junctions (TJs) are the most apical component of the junctional complexes in mammalian epithelial cells and form selective paracellular barriers restricting the passage of solutes and ions across the epithelial sheets. Claudins, a TJ integral membrane protein family, play a critical role in regulating paracellular barrier permeability. In the in vitro cell culture system, transepithelial electrical resistance (TER) measurement and the flux of radioisotope or fluorescent labeled molecules with different sizes have been widely used to determine the TJ barrier function. In the in vivo system, the tracer molecule Sulfo-NHS-Biotin was initially used in Xenopus embryo system and subsequently was successfully applied to a number of animal tissues in situ and in different organisms under the experimental conditions to examine the functional integrity of TJs by several laboratories. In this chapter, we will describe the detailed procedures of applying biotin as a paracellular tracer molecule to different in vivo systems to assay TJ barrier function.
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78
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Gupta IR, Ryan AK. Claudins: unlocking the code to tight junction function during embryogenesis and in disease. Clin Genet 2010; 77:314-25. [PMID: 20447145 DOI: 10.1111/j.1399-0004.2010.01397.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Claudins are the structural and molecular building blocks of tight junctions. Individual cells express more than one claudin family member, which suggests that a combinatorial claudin code that imparts flexibility and dynamic regulation of tight junction function could exist. Although we have learned much from manipulating claudin expression and function in cell lines, loss-of-function and gain-of-function experiments in animal model systems are essential for understanding how claudin-based boundaries function in the context of a living embryo and/or tissue. These in vivo manipulations have pointed to roles for claudins in maintaining the epithelial integrity of cell layers, establishing micro-environments and contributing to the overall shape of an embryo or tissue. In addition, loss-of-function mutations in combination with the characterization of mutations in human disease have demonstrated the importance of claudins in regulating paracellular transport of solutes and water during normal physiological states. In this review, we will discuss specific examples of in vivo studies that illustrate the function of claudin family members during development and in disease.
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Affiliation(s)
- I R Gupta
- Department of Pediatrics, McGill University, Montréal, Québec, Canada
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79
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Tight junctions: is there a role in dermatology? Arch Dermatol Res 2010; 302:483-93. [PMID: 20563589 DOI: 10.1007/s00403-010-1058-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 05/28/2010] [Accepted: 05/31/2010] [Indexed: 02/07/2023]
Abstract
A variety of tight junction (TJ) proteins including claudins, occludin, tricellulin, zonula occludens-proteins and junctional adhesion molecules have been identified in complex localization patterns in mammalian epidermis. Their expression and/or localization is frequently altered in skin diseases including skin tumors. However, our understanding of the function(s) of TJ and TJ proteins in the skin is, even though rapidly increasing, still limited. This review summarizes our current knowledge of the involvement of TJ and TJ proteins in mammalian skin in functions ascribed to TJ in simple epithelia, such as barrier function, polarity, gene expression, proliferation, differentiation, and vesicle transport.
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80
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The epidermal Ca(2+) gradient: Measurement using the phasor representation of fluorescent lifetime imaging. Biophys J 2010; 98:911-21. [PMID: 20197045 DOI: 10.1016/j.bpj.2009.10.055] [Citation(s) in RCA: 86] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 09/30/2009] [Accepted: 10/13/2009] [Indexed: 11/21/2022] Open
Abstract
Ionic gradients are found across a variety of tissues and organs. In this report, we apply the phasor representation of fluorescence lifetime imaging data to the quantitative study of ionic concentrations in tissues, overcoming technical problems of tissue thickness, concentration artifacts of ion-sensitive dyes, and calibration across inhomogeneous tissue. We used epidermis as a model system, as Ca(2+) gradients in this organ have been shown previously to control essential biologic processes of differentiation and formation of the epidermal permeability barrier. The approach described here allowed much better localization of Ca(2+) stores than those used in previous studies, and revealed that the bulk of free Ca(2+) measured in the epidermis comes from intracellular Ca(2+) stores such as the Golgi and the endoplasmic reticulum, with extracellular Ca(2+) making a relatively small contribution to the epidermal Ca(2+) gradient. Due to the high spatial resolution of two-photon microscopy, we were able to measure a marked heterogeneity in average calcium concentrations from cell to cell in the basal keratinocytes. This finding, not reported in previous studies, calls into question the long-held hypothesis that keratinocytes increase intracellular Ca(2+), cease proliferation, and differentiate passively in response to changes in extracellular Ca(2+). The experimental results obtained using this approach illustrate the power of the experimental and analytical techniques outlined in this report. Our approach can be used in mechanistic studies to address the formation, maintenance, and function of the epidermal Ca(2+) gradient, and it should be broadly applicable to the study of other tissues with ionic gradients.
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81
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Enikanolaiye A, Larivière N, Troy TC, Arabzadeh A, Atasoy E, Turksen K. Involucrin–claudin-6 tail deletion mutant (CΔ206) transgenic mice: a model of delayed epidermal permeability barrier formation and repair. Dis Model Mech 2010; 3:167-80. [DOI: 10.1242/dmm.002634] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
SUMMARY
Preterm birth is a major global health problem that results in a large number of infant deaths, many of which are attributable to the complications of an immature epidermal permeability barrier (EPB), for which there is currently no effective therapeutic option. The mammalian EPB is formed during development and is essential for survival as it maintains thermoregulation and hydration, and provides a defense against infection. Using transgenic mouse technology, we have demonstrated the importance of claudin (Cldn)-containing tight junctions (TJs) in epidermal differentiation and, in particular, that epidermal suprabasal overexpression of Cldn6 results in an EPB-deficient phenotype that phenocopies the dysfunctional EPB of premature human infants. In this study, we used the same approach to target a Cldn6 tail deletion mutant to the epidermis of mice [involucrin (Inv)-Cldn6-CΔ206 transgenic mice]. The Inv-Cldn6-CΔ206 transgenic mice displayed a developmental delay in EPB formation, as shown by the expression of keratins and Cldns, and by X-Gal penetration assays. Trans-epidermal water loss measurements and immunolocalization studies indicated that the epidermal differentiation program was also perturbed in postnatal Inv-Cldn6-CΔ206 transgenic mice resulting in a delayed maturation. Notably, however, expression/localization of epidermal differentiation and maturation markers, including Cldns, indicated that the transgenic epidermis matured and normalized by postnatal day 10, which is 3 days after the wild-type epidermis. Our results suggest that activation of the extracellular signal-regulated kinase 1/2 (Erk1/2) pathway and Cldn1 phosphorylation are associated with the repair and maturation of the skin barrier processes. These studies provide additional support for the crucial role of Cldns in epidermal differentiation, maturation and the formation of the EPB, and describe a novel animal model for evaluating postnatal epidermal maturation and therapies that may accelerate the process.
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Affiliation(s)
- Adebola Enikanolaiye
- Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, Ottawa, Ontario K1Y 8L6, Canada
- Department of Cellular and Molecular Medicine and
| | - Nathalie Larivière
- Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, Ottawa, Ontario K1Y 8L6, Canada
- Department of Cellular and Molecular Medicine and
| | - Tammy-Claire Troy
- Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, Ottawa, Ontario K1Y 8L6, Canada
| | - Azadeh Arabzadeh
- Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, Ottawa, Ontario K1Y 8L6, Canada
- Department of Cellular and Molecular Medicine and
| | - Elif Atasoy
- Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, Ottawa, Ontario K1Y 8L6, Canada
- Department of Cellular and Molecular Medicine and
| | - Kursad Turksen
- Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, Ottawa, Ontario K1Y 8L6, Canada
- Department of Cellular and Molecular Medicine and
- Department of Medicine, Divisions of Dermatology and Endocrinology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada
- Present address: Regenerative Medicine Program, Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, 501 Smyth Road-CCW5226, Ottawa, Ontario K1Y 8L6, Canada
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Elkouby-Naor L, Ben-Yosef T. Functions of claudin tight junction proteins and their complex interactions in various physiological systems. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2010; 279:1-32. [PMID: 20797675 DOI: 10.1016/s1937-6448(10)79001-8] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Members of the claudin family of proteins are the main components of tight junctions (TJs), the major selective barrier of the paracellular pathway between epithelial cells. As such, the claudins have the ability to generate the TJ physiological barrier and to control various physiological processes. Therefore, the importance of this family of proteins is obvious and many efforts were made to reveal different aspects of claudin TJ protein biology. In this review, we discuss recent advances in our understanding of claudin structure and function, as well as their distribution pattern in different organs and tissues. We mainly highlight the complex interactions of claudins in various physiological systems and suggest a possible role for a coregulation mechanism.
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Affiliation(s)
- Liron Elkouby-Naor
- Department of Genetics, The Rappaport Family Institute for Research in the Medical Sciences, Technion-Israel Institute of Technology, Haifa, Israel
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Turksen K. Wasted salts and wasted bodies: new insight into the role of claudin 7 in the kidney. Am J Physiol Renal Physiol 2010; 298:F22-3. [DOI: 10.1152/ajprenal.00594.2009] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Affiliation(s)
- Kursad Turksen
- Regenerative Medicine Program, Sprott Centre for Stem Cell Research, Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
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84
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Turksen K, Troy TC. Claudin is Skin Deep. CURRENT TOPICS IN MEMBRANES 2010. [DOI: 10.1016/s1063-5823(10)65011-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Tatum R, Zhang Y, Salleng K, Lu Z, Lin JJ, Lu Q, Jeansonne BG, Ding L, Chen YH. Renal salt wasting and chronic dehydration in claudin-7-deficient mice. Am J Physiol Renal Physiol 2010; 298:F24-F34. [PMID: 19759267 PMCID: PMC2806124 DOI: 10.1152/ajprenal.00450.2009] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Accepted: 09/14/2009] [Indexed: 02/08/2023] Open
Abstract
Claudin-7, a member of the claudin family, is highly expressed in distal nephrons of kidneys and has been reported to be involved in the regulation of paracellular Cl(-) permeability in cell cultures. To investigate the role of claudin-7 in vivo, we generated claudin-7 knockout mice (Cln7(-/-)) by the gene-targeting deletion method. Here we report that Cln7(-/-) mice were born viable, but died within 12 days after birth. Cln7(-/-) mice showed severe salt wasting, chronic dehydration, and growth retardation. We found that urine Na(+), Cl(-), and K(+) were significantly increased in Cln7(-/-) mice compared with that of Cln7(+/+) mice. Blood urea nitrogen and hematocrit were also significantly higher in Cln7(-/-) mice. The wrinkled skin was evident when Cln7(-/-) mice were approximately 1 wk old, indicating that they suffered from chronic fluid loss. Transepidermal water loss measurements showed no difference between Cln7(+/+) and Cln7(-/-) skin, suggesting that there was no transepidermal water barrier defect in Cln7(-/-) mice. Claudin-7 deletion resulted in the dramatic increase of aldosterone synthase mRNA level as early as 2 days after birth. The significant increases of epithelial Na(+) channel alpha, Na(+)-Cl(-) cotransporter, and aquaporin 2 mRNA levels revealed a compensatory response to the loss of electrolytes and fluid in Cln7(-/-) mice. Na(+)-K(+)-ATPase alpha(1) expression level was also greatly increased in distal convoluted tubules and collecting ducts where claudin-7 is normally expressed. Our study demonstrates that claudin-7 is essential for NaCl homeostasis in distal nephrons, and the paracellular ion transport pathway plays indispensable roles in keeping ionic balance in kidneys.
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Rendón-Huerta E, Teresa F, Teresa GM, Xochitl GS, Georgina AF, Veronica ZZ, Montaño LF. Distribution and expression pattern of claudins 6, 7, and 9 in diffuse- and intestinal-type gastric adenocarcinomas. J Gastrointest Cancer 2009; 41:52-9. [PMID: 19960275 DOI: 10.1007/s12029-009-9110-y] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2009] [Accepted: 11/02/2009] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Intestinal- and diffuse-type gastric adenocarcinomas differ in clinical outcome and genetic profile. Abnormal claudin expression has been well documented in several malignancies. Our aim was to find specific claudin markers for each type. METHODS Fifty paraffin-embedded tissue blocks of diffuse- and intestinal-type gastric adenocarcinomas and fresh gastric biopsies obtained endoscopically from 20 patients with a presumptive diagnosis of gastric cancer were analyzed. Claudin-specific polyclonal and monoclonal antibodies were used for immunohistochemistry and Western blot analysis in total lysate and subcellular fractions. RESULTS Claudin-6 expression was high in both types. Claudin-7 was expressed mainly in the diffuse-type whereas claudin-9 was mainly found in the apical membrane of the gland cells in the intestinal-type. Strong claudin-9 expression was associated with higher mortality rate (66%) in the diffuse type vs the intestinal type (25%) after a 2-year follow-up. CONCLUSION Claudins 6, 7, and 9 expressions are closely related to gastric carcinogenesis, and their detection is a useful prognostic marker in "intestinal-" and "diffuse-type" gastric adenocarcinomas.
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Affiliation(s)
- Erika Rendón-Huerta
- Depto Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Ciudad Universitaria, México, DF, México
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Törmä H, Berne B. Sodium lauryl sulphate alters the mRNA expression of lipid-metabolizing enzymes and PPAR signalling in normal human skinin vivo. Exp Dermatol 2009; 18:1010-5. [DOI: 10.1111/j.1600-0625.2009.00877.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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88
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Troy TC, Arabzadeh A, Larivière NMK, Enikanolaiye A, Turksen K. Dermatitis and aging-related barrier dysfunction in transgenic mice overexpressing an epidermal-targeted claudin 6 tail deletion mutant. PLoS One 2009; 4:e7814. [PMID: 19915705 PMCID: PMC2773045 DOI: 10.1371/journal.pone.0007814] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Accepted: 10/20/2009] [Indexed: 12/12/2022] Open
Abstract
The barrier function of the skin protects the mammalian body against infection, dehydration, UV irradiation and temperature fluctuation. Barrier function is reduced with the skin's intrinsic aging process, however the molecular mechanisms involved are unknown. We previously demonstrated that Claudin (Cldn)-containing tight junctions (TJs) are essential in the development of the epidermis and that transgenic mice overexpressing Cldn6 in the suprabasal layers of the epidermis undergo a perturbed terminal differentiation program characterized in part by reduced barrier function. To dissect further the mechanisms by which Cldn6 acts during epithelial differentiation, we overexpressed a Cldn6 cytoplasmic tail deletion mutant in the suprabasal compartment of the transgenic mouse epidermis. Although there were no gross phenotypic abnormalities at birth, subtle epidermal anomalies were present that disappeared by one month of age, indicative of a robust injury response. However, with aging, epidermal changes with eventual chronic dermatitis appeared with a concomitant barrier dysfunction manifested in increased trans-epidermal water loss. Immunohistochemical analysis revealed aberrant suprabasal Cldn localization with marked down-regulation of Cldn1. Both the proliferative and terminal differentiation compartments were perturbed as evidenced by mislocalization of multiple epidermal markers. These results suggest that the normally robust injury response mechanism of the epidermis is lost in the aging Involucrin-Cldn6-CΔ196 transgenic epidermis, and provide a model for evaluation of aging-related skin changes.
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Affiliation(s)
- Tammy-Claire Troy
- Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
| | - Azadeh Arabzadeh
- Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Nathalie M. K. Larivière
- Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Adebola Enikanolaiye
- Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | - Kursad Turksen
- Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, Ottawa, Ontario, Canada
- Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Divisions of Dermatology and Endocrinology, Department of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- Division of Reproductive Endocrinology, Department of Obstetrics, Gynaecology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
- * E-mail:
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D'Souza T, Sherman-Baust CA, Poosala S, Mullin JM, Morin PJ. Age-related changes of claudin expression in mouse liver, kidney, and pancreas. J Gerontol A Biol Sci Med Sci 2009; 64:1146-53. [PMID: 19692671 DOI: 10.1093/gerona/glp118] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Tight junctions (TJs) play crucial roles in tissue homeostasis and inflammation through their roles in the control of paracellular transport and barrier function. There is evidence that these functions are compromised in older organisms, but the exact mechanisms leading to TJ deterioration are not well understood. Claudin proteins are a family of membrane proteins that constitute the structural barrier elements of TJs and therefore play a major role in their formation and function. Using immunohistochemistry and immunoblotting, we have studied the expression of six different claudin proteins (claudin-1, -2, -3, -4, -5, and -7) in three tissues (liver, kidney, and pancreas) of aging male and female mice. In general, we find an age-dependent decrease in the expression of several claudin proteins in all three tissues observed, although the exact changes are tissue specific. Our findings provide a possible basis for the decrease in tissue barrier function in older organisms.
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Affiliation(s)
- Theresa D'Souza
- Laboratory of Cellular and Molecular Biology, National Institute on Aging, NIH Biomedical Research Center, Baltimore, MD 21224, USA
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Arabzadeh A, Troy TC, Turksen K. Insights into the role of the calcium sensing receptor in epidermal differentiation in vivo. Mol Biotechnol 2009; 43:264-72. [PMID: 19578997 DOI: 10.1007/s12033-009-9196-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2009] [Accepted: 06/16/2009] [Indexed: 11/25/2022]
Abstract
While the important role of calcium (Ca(++)) signaling is fundamental in epidermal cell physiology, a detailed knowledge of precisely how epidermal cells respond to Ca(++) levels is not clear. Using peptide-specific antibodies that we generated, we set out to evaluate the temporal and spatial distribution pattern of the Ca(++)-sensing receptor (CaSR) during epidermogenesis and to assess its involvement in the mature epidermis (e.g., in acute injury and tumorigenesis). Our data indicate a developmentally regulated expression of CaSR: up-regulation occurs in specific epidermal cells and cell layers in normal development or in response to injury when epidermal cells are induced to undergo commitment and early differentiation events, and down-regulation occurs in terminal differentiation stages. These results provide a new perspective on the role of the CaSR in these processes and describe a novel tool for evaluating Ca(++)-mediated epidermal differentiation.
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Affiliation(s)
- Azadeh Arabzadeh
- Sprott Centre for Stem Cell Research at the Ottawa Hospital Research Institute, Ottawa, ON, K1Y 8L6, Canada
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91
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Groschwitz KR, Hogan SP. Intestinal barrier function: molecular regulation and disease pathogenesis. J Allergy Clin Immunol 2009; 124:3-20; quiz 21-2. [PMID: 19560575 PMCID: PMC4266989 DOI: 10.1016/j.jaci.2009.05.038] [Citation(s) in RCA: 1226] [Impact Index Per Article: 76.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Revised: 05/22/2009] [Accepted: 05/27/2009] [Indexed: 02/08/2023]
Abstract
The intestinal epithelium is a single-cell layer that constitutes the largest and most important barrier against the external environment. It acts as a selectively permeable barrier, permitting the absorption of nutrients, electrolytes, and water while maintaining an effective defense against intraluminal toxins, antigens, and enteric flora. The epithelium maintains its selective barrier function through the formation of complex protein-protein networks that mechanically link adjacent cells and seal the intercellular space. The protein networks connecting epithelial cells form 3 adhesive complexes: desmosomes, adherens junctions, and tight junctions. These complexes consist of transmembrane proteins that interact extracellularly with adjacent cells and intracellularly with adaptor proteins that link to the cytoskeleton. Over the past decade, there has been increasing recognition of an association between disrupted intestinal barrier function and the development of autoimmune and inflammatory diseases. In this review we summarize the evolving understanding of the molecular composition and regulation of intestinal barrier function. We discuss the interactions between innate and adaptive immunity and intestinal epithelial barrier function, as well as the effect of exogenous factors on intestinal barrier function. Finally, we summarize clinical and experimental evidence demonstrating intestinal epithelial barrier dysfunction as a major factor contributing to the predisposition to inflammatory diseases, including food allergy, inflammatory bowel diseases, and celiac disease.
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Affiliation(s)
- Katherine R. Groschwitz
- Division of Allergy and Immunology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH
- Division of Immunobiology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH
| | - Simon P. Hogan
- Division of Allergy and Immunology, Department of Pediatrics, Cincinnati Children’s Hospital Medical Center, University of Cincinnati College of Medicine, Cincinnati, OH
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92
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Yuan X, Lin X, Manorek G, Kanatani I, Cheung LH, Rosenblum MG, Howell SB. Recombinant CPE fused to tumor necrosis factor targets human ovarian cancer cells expressing the claudin-3 and claudin-4 receptors. Mol Cancer Ther 2009; 8:1906-15. [PMID: 19567823 DOI: 10.1158/1535-7163.mct-09-0106] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Xiaoqin Yuan
- Department of Medicine and the Rebecca and John Moores University of California San Diego Cancer Center, University of California San Diego, La Jolla, CA 92093, USA
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93
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Michels C, Aghdam SY, Niessen CM. Cadherin-Mediated Regulation of Tight Junctions in Stratifying Epithelia. Ann N Y Acad Sci 2009; 1165:163-8. [DOI: 10.1111/j.1749-6632.2009.04443.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
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94
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Abstract
Transmembrane proteins known as claudins play a critical role in tight junctions by regulating paracellular barrier permeability. The control of claudin assembly into tight junctions requires a complex interplay between several classes of claudins, other transmembrane proteins and scaffold proteins. Claudins are also subject to regulation by post-translational modifications including phosphorylation and palmitoylation. Several human diseases have been linked to claudin mutations, underscoring the physiologic function of these proteins. Roles for claudins in regulating cell phenotype and growth control also are beginning to emerge, suggesting a multifaceted role for claudins in regulation of cells beyond serving as a simple structural element of tight junctions.
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Affiliation(s)
- Mary K Findley
- Division of Pulmonary, Allergy and Critical Care Medicine, Emory University School of Medicine, Atlanta, Georgia 30322, USA
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95
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Miyamoto T, Momoi A, Kato K, Kondoh H, Tsukita S, Furuse M, Furutani-Seiki M. Generation of transgenic medaka expressing claudin7-EGFP for imaging of tight junctions in living medaka embryos. Cell Tissue Res 2009; 335:465-71. [PMID: 19037661 DOI: 10.1007/s00441-008-0726-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2008] [Accepted: 10/20/2008] [Indexed: 11/27/2022]
Abstract
The tight junction (TJ) is a specialized cell-cell adhesion structure in epithelial and endothelial sheets unique to the chordates and functions as a barrier of fluidal diffusion across the cell sheets. In order to study the dynamics of TJ formation in vivo during embryogenesis, we have generated a transgenic medaka line that expresses claudin-7 protein fused to enhanced green fluorescent protein under the regulation of the red seabream beta-actin promoter in transparent medaka embryos. Claudins contain four transmembrane domains and have been identified as the key molecules that dictate the function of TJs. This transgenic medaka line will thus be useful for imaging of TJs in living embryos and hence in screening for mutations affecting cell-cell adhesion.
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Affiliation(s)
- Tatsuo Miyamoto
- Department of Cell Biology, Faculty of Medicine, Kyoto University, Kyoto 606-8501, Japan.
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96
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Sepulveda DE, Andrews BA, Asenjo JA, Papoutsakis ET. Comparative transcriptional analysis of embryoid body versus two-dimensional differentiation of murine embryonic stem cells. Tissue Eng Part A 2009; 14:1603-14. [PMID: 18433312 DOI: 10.1089/ten.tea.2007.0331] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Understanding the process of ex vivo embryonic stem (ES) cell differentiation is important for generating higher yields of desirable cell types or lineages and for understanding fundamental aspects of ES differentiation. We used DNA microarray analysis to investigate the differentiation of mouse ES cells cultured under three differentiation conditions. Embryoid body (EB) formation was compared to differentiation on surfaces coated with either gelatin (GEL) or matrigel (MAT). Based on the transcriptional patterns of a list of literature-based "stemness" genes, ES cell differentiation on the two coated surfaces appeared similar but not identical to EB differentiation. A notable difference was the GEL and MAT upregulation but EB downregulation of nine such stemness genes, which are related to cell adhesion and epithelial differentiation. Further, GEL and MAT differentiation showed higher expression of bone formation-related genes (Spp1, Csf1, Gsn, Bmp8b, Crlf1). Gene ontology analysis shows an increase in the expression of genes related to migration and cell structure in all three conditions. Overall, GEL and MAT conditions resulted in a more similar to each other transcriptional profile than to the EB condition, and such differences are apparently related to higher nutrient and metabolite gradients and limitations in the EB versus the GEL or MAT cultures.
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Affiliation(s)
- Dario E Sepulveda
- Department of Chemical Engineering and Biotechnology, Centre for Biochemical Engineering and Biotechnology, Institute for Cell Dynamics and Biotechnology (ICDB), University of Chile, Santiago, Chile
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97
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Eaton DC, Helms MN, Koval M, Bao HF, Jain L. The contribution of epithelial sodium channels to alveolar function in health and disease. Annu Rev Physiol 2009; 71:403-23. [PMID: 18831683 DOI: 10.1146/annurev.physiol.010908.163250] [Citation(s) in RCA: 146] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Amiloride-sensitive epithelial sodium channels (ENaC) play an important role in lung sodium transport. Sodium transport is closely regulated to maintain an appropriate fluid layer on the alveolar surface. Both alveolar type I and II cells have several different sodium-permeable channels in their apical membranes that play a role in normal lung physiology and pathophysiology. In many epithelial tissues, ENaC is formed from three subunit proteins: alpha, beta, and gamma ENaC. Part of the diversity of sodium-permeable channels in lung arises from assembling different combinations of these subunits to form channels with different biophysical properties and different mechanisms for regulation. Thus, lung epithelium has enormous flexibility to alter the magnitude of salt and water transport. In lung, ENaC is regulated by many transmitter and hormonal agents. Regulation depends upon the type of sodium channel but involves controlling the number of apical channels and/or the activity of individual channels.
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Affiliation(s)
- Douglas C Eaton
- Department of Physiology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.
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98
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Elkouby-Naor L, Abassi Z, Lagziel A, Gow A, Ben-Yosef T. Double gene deletion reveals lack of cooperation between claudin 11 and claudin 14 tight junction proteins. Cell Tissue Res 2008; 333:427-38. [PMID: 18663477 PMCID: PMC2943968 DOI: 10.1007/s00441-008-0621-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Accepted: 04/09/2008] [Indexed: 01/10/2023]
Abstract
Members of the claudin family of proteins are the main components of tight junctions (TJs), the major selective barrier of the paracellular pathway between epithelial cells. The selectivity and specificity of TJ strands are determined by the type of claudins present. An understanding of the cooperation between different claudins in various tissues is thus important. To study the possible cooperation between claudin 11 and claudin 14, we have generated claudin 11/claudin 14 double-deficient mice, which exhibit a combination of the phenotypes found in each of the singly deficient mutants, including deafness, neurological deficits, and male sterility. These two claudins have distinct and partially overlapping expression patterns in the kidney. Claudin 11 is located in both the proximal and distal convoluted tubules, whereas claudin 14 occurs in both the thin descending and thick ascending limbs of the loop of Henle and in the proximal convoluted tubules. Although daily urinary excretion of Mg(++), and to a lesser extent of Ca(++), tends to be higher in claudin 11/claudin 14 double mutants, these changes do not reach statistical significance compared with wild-type animals. Thus, under normal conditions, co-deletion of claudin 11 and claudin 14 does not affect kidney function or ion balance. Our data demonstrate that, despite the importance of each of these claudins, there is probably no functional cooperation between them. Generation of additional mouse models in which different claudins are abolished should provide further insight into the complex interactions between claudin proteins in various physiological systems.
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Affiliation(s)
- Liron Elkouby-Naor
- Department of Genetics, The Rappaport Family Institute for Research in the Medical Sciences, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Zaid Abassi
- Department of Physiology and Biophysics, The Rappaport Family Institute for Research in the Medical Sciences, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Ayala Lagziel
- Section on Human Genetics, Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Rockville, Maryland, USA
| | - Alexander Gow
- Center for Molecular Medicine and Genetics, Carman and Ann Adams Department of Pediatrics, Department of Neurology, Wayne State University, Detroit, Michigan, USA
| | - Tamar Ben-Yosef
- Department of Genetics, The Rappaport Family Institute for Research in the Medical Sciences, Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
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99
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Yamamoto T, Saeki Y, Kurasawa M, Kuroda S, Arase S, Sasaki H. Effect of RNA interference of tight junction-related molecules on intercellular barrier function in cultured human keratinocytes. Arch Dermatol Res 2008; 300:517-24. [PMID: 18560860 DOI: 10.1007/s00403-008-0868-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2008] [Revised: 05/12/2008] [Accepted: 05/28/2008] [Indexed: 10/21/2022]
Abstract
Accumulating evidence shows that tight junctions (TJs) in the granular layer contribute to the epidermal barrier, suggesting that the regulation of TJ assembly in keratinocytes may provide a clue to understanding the role of barrier formation in epidermis. In this study, we investigated the behavior of TJ-related molecules in cultured human keratinocytes during keratinization induced by transfer to high-calcium medium, and the effect of RNA interference of TJ-related molecules on intercellular permeability and morphological features. The expression of TJ-related molecules and transepithelial electrical resistance were increased by transfer to high-calcium medium. In cells under the same conditions, we observed by freeze-fracture electron microscopy that TJ strands developed on the apposing cell membranes. In contrast, the transepithelial electrical resistance was clearly suppressed when the expression of claudin-1 or occludin was blocked by RNA interference. The morphological features of these knock-down cells were the same as those of MOCK cells, except for a marked decrease in the number of TJ strands. Furthermore, claudin-1 suppression inhibited occludin localization at the cell membrane, whereas suppression of occludin did not influence the localization of claudin-1. These results suggest that claudin-1 plays a crucial role in recruiting occludin to TJs, and that occludin is involved in intercellular barrier function.
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Affiliation(s)
- Takuya Yamamoto
- Department of Dermatology, Institute of Health Biosciences, The University of Tokushima Graduate School, 3-18-15, Kuramoto, Tokushima, 770-8503, Japan
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100
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Anderson WJ, Zhou Q, Alcalde V, Kaneko OF, Blank LJ, Sherwood RI, Guseh JS, Rajagopal J, Melton DA. Genetic targeting of the endoderm with claudin-6CreER. Dev Dyn 2008; 237:504-12. [PMID: 18213590 PMCID: PMC2665265 DOI: 10.1002/dvdy.21437] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
A full description of the ontogeny of the beta cell would guide efforts to generate beta cells from embryonic stem cells (ESCs). The first step requires an understanding of definitive endoderm: the genes and signals responsible for its specification, proliferation, and patterning. This report describes a global marker of definitive endoderm, Claudin-6 (Cldn6). We report its expression in early development with particular attention to definitive endoderm derivatives. To create a genetic system to drive gene expression throughout the definitive endoderm with both spatial and temporal control, we target the endogenous locus with an inducible Cre recombinase (Cre-ER(T2)) cassette. Cldn6 null mice are viable and fertile with no obvious phenotypic abnormalities. We also report a lineage analysis of the fate of Cldn6-expressing embryonic cells, which is relevant to the development of the pancreas, lung, and liver.
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Affiliation(s)
- William J Anderson
- Department of Molecular and Cellular Biology, Howard Hughes Medical Institute, Harvard Stem Cell Institute, Harvard University, Cambridge, Massachusetts 02138, USA
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