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Essa AAM. Downregulation of connexin 43 is crucial for basal cell alignment in ameloblastoma and odontogenic keratocyst. Saudi Dent J 2024; 36:990-994. [PMID: 39035567 PMCID: PMC11255922 DOI: 10.1016/j.sdentj.2024.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2023] [Revised: 05/04/2024] [Accepted: 05/06/2024] [Indexed: 07/23/2024] Open
Abstract
Background The current study aims at investigating gap junctions which allow cells to connect with one another. Such process is essential for cell differentiation and the preservation of diverse cell functions. It is noticeable that connexin 43 (Cnx43) was differentially expressed in ameloblasts and odontoblasts in the processes of odontogenesis. Moreover, in carcinoma in situ (CIS) and oral squamous cell carcinoma (SCC), Cnx43 expression apparently thought to be a defining feature of the neoplastic state of squamous epithelial cells. Aim: Therefore, the study has postulated that Cnx43 may be involved in the pathophysiology of ameloblastoma and certain odontogenic cysts whose epithelial constituents exhibit squamous cells. Materials and methods In order to prove the foregoing hypothesis, the study explored the immunohistochemical profiles of Cnx43 in ameloblastoma as well as some odontogenic cysts to assess Cnx43 trafficking and its relation with characteristic tissue architectures of odontogenic lesions. Results: The study has concluded that Cnx43 was down regulated significantly in follicular ameloblastoma with obvious ameloblasts-like cell components as well as in odontogenic keratocyst with palisaded basal cells. Additionally, other patterns of ameloblastoma (plexiform and desmoplastic) and different types of odontogenic cysts manifest heavy trafficking for Cnx43. Conclusion: Finally, altered Cnx43 expression between various patterns of ameloblastoma and odontogenic cysts might be related to their pathogenesis and is responsible for their morphological diversity.
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Affiliation(s)
- Ahmed Abdelaziz Mohamed Essa
- Assistant Professor of Oral Pathology, Oral Pathology Department, Faculty of Dentistry, Tanta University, Egypt
- Assistant Professor of Oral Pathology, Department of Biomedical Dental Sciences, Faculty of Dentistry, Al-Baha University, Saudi Arabia
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2
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Sun-Wada GH, Wada Y. Exploring the Link between Vacuolar-Type Proton ATPase and Epithelial Cell Polarity. Biol Pharm Bull 2022; 45:1419-1425. [PMID: 36184498 DOI: 10.1248/bpb.b22-00205] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vacuolar-type H+-ATPase (V-ATPase) was first identified as an electrogenic proton pump that acidifies the lumen of intracellular organelles. Subsequently, it was observed that the proton pump also participates in the acidification of extracellular compartments. V-ATPase plays important roles in a wide range of cell biological processes and physiological functions by generating an acidic pH; therefore, it has attracted much attention not only in basic research but also in pathological and clinical aspects. Emerging evidence indicates that the luminal acidic endocytic organelles and their trafficking may function as important hubs that connect and coordinate various signaling pathways. Various pharmacological analyses have suggested that acidic endocytic organelles are important for the maintenance of cell polarity. Recently, several studies using genetic approaches have revealed the involvement of V-ATPase in the establishment and maintenance of apico-basal polarity. This review provides a brief overview of the relationship between the polarity of epithelial cells and V-ATPase as well as V-ATPase driven luminal acidification.
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Affiliation(s)
- Ge-Hong Sun-Wada
- Faculty of Pharmaceutical Sciences, Doshisha Women's College of Liberal Arts
| | - Yoh Wada
- Division of Biological Science, Institute of Scientific and Industrial Research, Osaka University
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3
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Yin J, Xu J, Cheng R, Shao M, Qin Y, Yang H, Hu T. Role of connexin 43 in odontoblastic differentiation and structural maintenance in pulp damage repair. Int J Oral Sci 2021; 13:1. [PMID: 33414369 PMCID: PMC7791050 DOI: 10.1038/s41368-020-00105-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 10/31/2020] [Accepted: 12/02/2020] [Indexed: 02/05/2023] Open
Abstract
Dental pulp can initiate its damage repair after an injury of the pulp–dentin complex by rearrangement of odontoblasts and formation of newly differentiated odontoblast-like cells. Connexin 43 (Cx43) is one of the gap junction proteins that participates in multiple tissue repair processes. However, the role of Cx43 in the repair of the dental pulp remains unclear. This study aimed to determine the function of Cx43 in the odontoblast arrangement patterns and odontoblastic differentiation. Human teeth for in vitro experiments were acquired, and a pulp injury model in Sprague-Dawley rats was used for in vivo analysis. The odontoblast arrangement pattern and the expression of Cx43 and dentin sialophosphoprotein (DSPP) were assessed. To investigate the function of Cx43 in odontoblastic differentiation, we overexpressed or inhibited Cx43. The results indicated that polarized odontoblasts were arranged along the pulp–dentin interface and had high levels of Cx43 expression in the healthy teeth; however, the odontoblast arrangement pattern was slightly changed concomitant to an increase in the Cx43 expression in the carious teeth. Regularly arranged odontoblast-like cells had high levels of the Cx43 expression during the formation of mature dentin, but the odontoblast-like cells were not regularly arranged beneath immature osteodentin in the pulp injury models. Subsequent in vitro experiments demonstrated that Cx43 is upregulated during odontoblastic differentiation of the dental pulp cells, and inhibition or overexpression of Cx43 influence the odontoblastic differentiation. Thus, Cx43 may be involved in the maintenance of odontoblast arrangement patterns, and influence the pulp repair outcomes by the regulation of odontoblastic differentiation.
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Affiliation(s)
- Jiaxin Yin
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China.,Department of Endodontics, School of Stomatology, Capital Medical University, Beijing, China
| | - Jue Xu
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
| | - Ran Cheng
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Meiying Shao
- West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
| | - Yuandong Qin
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Hui Yang
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China.
| | - Tao Hu
- State Key Laboratory of Oral Diseases & National Clinical Research Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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4
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Lian G, Chenn A, Ekuta V, Kanaujia S, Sheen V. Formin 2 Regulates Lysosomal Degradation of Wnt-Associated β-Catenin in Neural Progenitors. Cereb Cortex 2020; 29:1938-1952. [PMID: 29659741 DOI: 10.1093/cercor/bhy073] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2017] [Revised: 02/14/2018] [Accepted: 03/13/2018] [Indexed: 01/07/2023] Open
Abstract
Although neural progenitor proliferation along the ventricular zone is regulated by β-catenin through Wnt signaling, the cytoskeletal mechanisms that regulate expression and localization of these proteins are not well understood. Our prior studies have shown that loss of the actin-binding Filamin A (FlnA) and actin-nucleating protein Formin 2 (Fmn2) impairs endocytosis of low-density-lipoprotein-receptor-related protein 6 (Lrp6), thereby disrupting β-catenin activation, resulting in decreased brain size. Here, we report that activated RhoA-GTPase disengages Fmn2 N- to C-terminal binding to promote Fmn2 activation and redistribution into lysosomal vesicles. Fmn2 colocalizes with β-catenin in lysosomes and promotes its degradation. Further, Fmn2 binds the E3 ligase Smurf2, enhances Smurf2-dependent ubiquitination, and degradation of Dishevelled-2 (Dvl2), thereby initiates β-catenin degradation. Finally, Fmn2 overexpression disrupts neuroepithelial integrity, neuronal migration, and proliferation-phenotypes in E13 mouse embryos, as seen with loss of Fmn2+FlnA function. Conversely, co-expression of Dvl2 with Fmn2 rescues the proliferation defect due to Fmn2 overexpression in mouse embryos. These findings suggest that there is a homeostatic feedback mechanism in the cytoskeletal-dependent regulation of neural proliferation within the cerebral cortex. Upstream, Fmn2 promotes proliferation by stabilizing the Lrp6 receptor, leading to β-catenin activation. Downstream, RhoA-activated Fmn2 promotes lysosomal degradation of Dvl2, leading to β-catenin degradation.
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Affiliation(s)
- Gewei Lian
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Anjen Chenn
- Department of Pathology, University of Illinois College of Medicine, Chicago, IL, USA
| | - Victor Ekuta
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Sneha Kanaujia
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
| | - Volney Sheen
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA, USA
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5
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Zhou YJ, Yan GX, Liu CW, Zhang X, Hu Y, Hao XQ, Zhao H, Shi C, Sun HC. [Polarity of ameloblasts and odontoblasts and their related regulators]. HUA XI KOU QIANG YI XUE ZA ZHI = HUAXI KOUQIANG YIXUE ZAZHI = WEST CHINA JOURNAL OF STOMATOLOGY 2019; 37:309-313. [PMID: 31218868 DOI: 10.7518/hxkq.2019.03.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The polarity of ameloblasts and odontoblasts is crucial for their differentiation and function. Polarity-related molecules play an important role in this process. This review summarizes the process of polarity formation of ameloblasts and odontoblasts and their related regulators.
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Affiliation(s)
- Yi-Jun Zhou
- Dept. of Oral Pathology, School and Hospital of Stomatology, Jilin University, Key Laboratory of Tooth Development and Bone Remodeling of Jilin Province, Changchun 130021, China
| | - Guang-Xing Yan
- Dept. of Oral Pathology, School and Hospital of Stomatology, Jilin University, Key Laboratory of Tooth Development and Bone Remodeling of Jilin Province, Changchun 130021, China
| | - Cang-Wei Liu
- Dept. of Oral Pathology, School and Hospital of Stomatology, Jilin University, Key Laboratory of Tooth Development and Bone Remodeling of Jilin Province, Changchun 130021, China
| | - Xue Zhang
- Dept. of Oral Pathology, School and Hospital of Stomatology, Jilin University, Key Laboratory of Tooth Development and Bone Remodeling of Jilin Province, Changchun 130021, China
| | - Yue Hu
- Dept. of Oral Pathology, School and Hospital of Stomatology, Jilin University, Key Laboratory of Tooth Development and Bone Remodeling of Jilin Province, Changchun 130021, China
| | - Xin-Qing Hao
- Dept. of Oral Pathology, School and Hospital of Stomatology, Jilin University, Key Laboratory of Tooth Development and Bone Remodeling of Jilin Province, Changchun 130021, China
| | - Huan Zhao
- Dept. of Oral Pathology, School and Hospital of Stomatology, Jilin University, Key Laboratory of Tooth Development and Bone Remodeling of Jilin Province, Changchun 130021, China
| | - Ce Shi
- Dept. of Oral Pathology, School and Hospital of Stomatology, Jilin University, Key Laboratory of Tooth Development and Bone Remodeling of Jilin Province, Changchun 130021, China
| | - Hong-Chen Sun
- Dept. of Oral Pathology, School and Hospital of Stomatology, Jilin University, Key Laboratory of Tooth Development and Bone Remodeling of Jilin Province, Changchun 130021, China
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6
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Vendel KJA, Tschirpke S, Shamsi F, Dogterom M, Laan L. Minimal in vitro systems shed light on cell polarity. J Cell Sci 2019; 132:132/4/jcs217554. [PMID: 30700498 DOI: 10.1242/jcs.217554] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Cell polarity - the morphological and functional differentiation of cellular compartments in a directional manner - is required for processes such as orientation of cell division, directed cellular growth and motility. How the interplay of components within the complexity of a cell leads to cell polarity is still heavily debated. In this Review, we focus on one specific aspect of cell polarity: the non-uniform accumulation of proteins on the cell membrane. In cells, this is achieved through reaction-diffusion and/or cytoskeleton-based mechanisms. In reaction-diffusion systems, components are transformed into each other by chemical reactions and are moving through space by diffusion. In cytoskeleton-based processes, cellular components (i.e. proteins) are actively transported by microtubules (MTs) and actin filaments to specific locations in the cell. We examine how minimal systems - in vitro reconstitutions of a particular cellular function with a minimal number of components - are designed, how they contribute to our understanding of cell polarity (i.e. protein accumulation), and how they complement in vivo investigations. We start by discussing the Min protein system from Escherichia coli, which represents a reaction-diffusion system with a well-established minimal system. This is followed by a discussion of MT-based directed transport for cell polarity markers as an example of a cytoskeleton-based mechanism. To conclude, we discuss, as an example, the interplay of reaction-diffusion and cytoskeleton-based mechanisms during polarity establishment in budding yeast.
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Affiliation(s)
- Kim J A Vendel
- Bionanoscience Department, Kavli Institute of Nanoscience, Delft University of Technology, Delft 2600 GA, The Netherlands
| | - Sophie Tschirpke
- Bionanoscience Department, Kavli Institute of Nanoscience, Delft University of Technology, Delft 2600 GA, The Netherlands
| | - Fayezeh Shamsi
- Bionanoscience Department, Kavli Institute of Nanoscience, Delft University of Technology, Delft 2600 GA, The Netherlands
| | - Marileen Dogterom
- Bionanoscience Department, Kavli Institute of Nanoscience, Delft University of Technology, Delft 2600 GA, The Netherlands
| | - Liedewij Laan
- Bionanoscience Department, Kavli Institute of Nanoscience, Delft University of Technology, Delft 2600 GA, The Netherlands
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7
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Cao Y, Lei Y, Luo Y, Tan T, Du B, Zheng Y, Sun L, Liang Q. The actomyosin network is influenced by NMHC IIA and regulated by Crp F46, which is involved in controlling cell migration. Exp Cell Res 2018; 373:119-131. [PMID: 30336116 DOI: 10.1016/j.yexcr.2018.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2018] [Revised: 10/08/2018] [Accepted: 10/09/2018] [Indexed: 10/28/2022]
Abstract
When a cell migrates, the centrosome positions between the nucleus and the leading edge of migration via the microtubule system. The protein CrpF46 (centrosome-related protein F46) has a known role during mitosis and centrosome duplication. However, how CrpF46 efficiently regulates centrosome-related cell migration is unclear. Here, we report that knockdown of CrpF46 resulted in the disruption of microtubule arrangement, with impaired centrosomal reorientation, and slowed down cell migration. In cells that express low levels of CrpF46, stress fibers were weakened, which could be rescued by recovering Flag-CrpF46. We also found that CrpF46 interacted with non-muscle myosin high chain IIA (NMHC IIA) and that its three coiled-coil domains are pivotal for its binding to NMHC IIA. Additionally, analyses of phosphorylation of NMHC IIA and RLC (regulatory light chain) demonstrated that CrpF46 was associated with myosin IIA during filament formation. Indirect immunofluorescence images indicated that NM IIA filaments were inhibited when CrpF46 was under-expressed. Thus, CrpF46 regulates cell migration by centrosomal reorientation and altering the function of the actomyosin network by controlling specific phosphorylation of myosin.
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Affiliation(s)
- Yang Cao
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, PR China; Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing 100875, PR China
| | - Yan Lei
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, PR China; Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing 100875, PR China
| | - Yang Luo
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, PR China
| | - Tan Tan
- School of Pharmacology and Biology, University of South China, Hunan Province Cooperative innovation Center for Molecular Target New Drug Study, Hengyang 421001, PR China
| | - Baochen Du
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, PR China
| | - Yanbo Zheng
- The Institute of Medical Biotechnology (IMB) of the Chinese Academy of Medical Sciences, Beijing 100050, PR China
| | - Le Sun
- AbMax Biotechnology Co., Beijing 101111, PR China
| | - Qianjin Liang
- Beijing Key Laboratory of Gene Resource and Molecular Development, College of Life Sciences, Beijing Normal University, Beijing 100875, PR China; Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Sciences, Beijing Normal University, Beijing 100875, PR China.
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8
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Shao S, Liao X, Xie F, Deng S, Liu X, Ristaniemi T, Liu B. FRET biosensor allows spatio-temporal observation of shear stress-induced polar RhoGDIα activation. Commun Biol 2018; 1:224. [PMID: 30564745 PMCID: PMC6288100 DOI: 10.1038/s42003-018-0232-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2018] [Accepted: 11/14/2018] [Indexed: 12/25/2022] Open
Abstract
Rho GDP-dissociation inhibitor α (RhoGDIα) is a known negative regulator of the Rho family that shuts off GDP/GTP cycling and cytoplasm/membrane translocation to regulate cell migration. However, to our knowledge, no reports are available that focus on how the RhoGDIα-Rho GTPases complex is activated by laminar flow through exploring the activation of RhoGDIα itself. Here, we constructed a new biosensor using fluorescence resonance energy transfer (FRET) technology to measure the spatio-temporal activation of RhoGDIα in its binding with Rho GTPases in living HeLa cells. Using this biosensor, we find that the dissociation of the RhoGDIα-Rho GTPases complex is increased by shear stress, and its dissociation rate varies with subcellular location. Moreover, this process is mediated by membrane fluidity, cytoskeleton and Src activity, which indicates that the regulation of RhoGDIα activation under shear stress application represents a relatively separate pathway from the shear stress-induced Rho pathway.
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Affiliation(s)
- Shuai Shao
- School of Biomedical Engineering, Dalian University of Technology, Liaoning IC Technology Key Lab, 116024 Dalian, China
- Faculty of Information Technology, University of Jyväskylä, 40014 Jyväskylä, Finland
| | - Xiaoling Liao
- Biomaterials and Live Cell Imaging Institute, Chongqing University of Science and Technology, 401331 Chongqing, China
| | - Fei Xie
- School of Biomedical Engineering, Dalian University of Technology, Liaoning IC Technology Key Lab, 116024 Dalian, China
| | - Sha Deng
- School of Biomedical Engineering, Dalian University of Technology, Liaoning IC Technology Key Lab, 116024 Dalian, China
| | - Xue Liu
- Biomaterials and Live Cell Imaging Institute, Chongqing University of Science and Technology, 401331 Chongqing, China
| | - Tapani Ristaniemi
- Faculty of Information Technology, University of Jyväskylä, 40014 Jyväskylä, Finland
| | - Bo Liu
- School of Biomedical Engineering, Dalian University of Technology, Liaoning IC Technology Key Lab, 116024 Dalian, China
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9
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Matsuoka S, Ueda M. Mutual inhibition between PTEN and PIP3 generates bistability for polarity in motile cells. Nat Commun 2018; 9:4481. [PMID: 30367048 PMCID: PMC6203803 DOI: 10.1038/s41467-018-06856-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 10/02/2018] [Indexed: 12/13/2022] Open
Abstract
Phosphatidylinositol 3,4,5-trisphosphate (PIP3) and PIP3 phosphatase (PTEN) are enriched mutually exclusively on the anterior and posterior membranes of eukaryotic motile cells. However, the mechanism that causes this spatial separation between the two molecules is unknown. Here we develop a method to manipulate PIP3 levels in living cells and used it to show PIP3 suppresses the membrane localization of PTEN. Single-molecule measurements of membrane-association and -dissociation kinetics and of lateral diffusion reveal that PIP3 suppresses the PTEN binding site required for stable PTEN membrane binding. Mutual inhibition between PIP3 and PTEN provides a mechanistic basis for bistability that creates a PIP3-enriched/PTEN-excluded state and a PTEN-enriched/PIP3-excluded state underlying the strict spatial separation between PIP3 and PTEN. The PTEN binding site also mediates the suppression of PTEN membrane localization in chemotactic signaling. These results illustrate that the PIP3-PTEN bistable system underlies a cell's decision-making for directional movement irrespective of the environment.
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Affiliation(s)
- Satomi Matsuoka
- Laboratory for Cell Signaling Dynamics, RIKEN QBiC, 6-2-3, Furuedai, Suita, Osaka, 565-0874, Japan.
- Laboratory of Single Molecule Biology, Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan.
- Laboratory for Cell Signaling Dynamics, RIKEN BDR, 6-2-3, Furuedai, Suita, Osaka, 565-0874, Japan.
| | - Masahiro Ueda
- Laboratory for Cell Signaling Dynamics, RIKEN QBiC, 6-2-3, Furuedai, Suita, Osaka, 565-0874, Japan
- Laboratory of Single Molecule Biology, Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
- Laboratory of Single Molecule Biology, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka, 560-0043, Japan
- Laboratory for Cell Signaling Dynamics, RIKEN BDR, 6-2-3, Furuedai, Suita, Osaka, 565-0874, Japan
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10
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Mechanism of drug extrusion by brain endothelial cells via lysosomal drug trapping and disposal by neutrophils. Proc Natl Acad Sci U S A 2018; 115:E9590-E9599. [PMID: 30254169 PMCID: PMC6187170 DOI: 10.1073/pnas.1719642115] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Located at the apical (blood-facing) site of brain capillary endothelial cells that form the blood–brain barrier (BBB), the efflux transporter P-glycoprotein (Pgp) restricts the brain entry of various lipophilic xenobiotics, which contributes to BBB function. Pgp may become saturated if exposed to too-high drug concentrations. Here, we demonstrate a second-line defense mechanism in human brain capillary endothelial cells—that is, Pgp-mediated intracellular lysosomal drug trapping. Furthermore, we describe a mechanism of drug disposal at the BBB, which is shedding of lysosomal Pgp/substrate complexes at the apical membrane of human and porcine BBB endothelial cells and subsequent phagocytosis by neutrophils. Thus, we have discovered a fascinating mechanism of how Pgp might contribute to brain protection. The blood–brain barrier protects the brain against a variety of potentially toxic compounds. Barrier function results from tight junctions between brain capillary endothelial cells and high expression of active efflux transporters, including P-glycoprotein (Pgp), at the apical membrane of these cells. In addition to actively transporting drugs out of the cell, Pgp mediates lysosomal sequestration of chemotherapeutic drugs in cancer cells, thus contributing to drug resistance. Here, we describe that lysosomal sequestration of Pgp substrates, including doxorubicin, also occurs in human and porcine brain endothelial cells that form the blood–brain barrier. This is followed by shedding of drug-sequestering vesicular structures, which stay attached to the apical side of the plasma membrane and form aggregates (“barrier bodies”) that ultimately undergo phagocytosis by neutrophils, thus constituting an as-yet-undescribed mechanism of drug disposal. These findings introduce a mechanism that might contribute to brain protection against potentially toxic xenobiotics, including therapeutically important chemotherapeutic drugs.
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11
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Laumonnerie C, Solecki DJ. Regulation of Polarity Protein Levels in the Developing Central Nervous System. J Mol Biol 2018; 430:3472-3480. [PMID: 29864442 DOI: 10.1016/j.jmb.2018.05.036] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 05/28/2018] [Accepted: 05/29/2018] [Indexed: 12/21/2022]
Abstract
In the course of their development from neuroepithelial cells to mature neurons, neuronal progenitors proliferate, delaminate, differentiate, migrate, and extend processes to form a complex neuronal network. In addition to supporting the morphology of the neuroepithelium and radial glia, polarity proteins contribute to the remodeling of processes and support the architectural reorganizations that result in axon extension and dendrite formation. While a good amount of evidence highlights a rheostat-like regulation by signaling events leading to local activation and/or redistribution of polarity proteins, recent studies demonstrate a new paradigm involving a switch-like regulation directly controlling the availability of polarity protein at specific stage by transcriptional regulation and/or targeted ubiquitin proteasome degradation. During the process of differentiation, most neurons will adopt a morphology with reduced polarity which suggests that polarity complex proteins are strongly repressed during key step of development. Here we review the different mechanisms that directly impact the levels of polarity complex proteins in neurons in relation to the polarization context and discuss why this transient loss of polarity is essential to understand neural development and how this knowledge could be relevant for some neuropathy.
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Affiliation(s)
- Christophe Laumonnerie
- Department of Developmental Neurobiology, St Jude Children's Research Hospital, 262 Danny Thomas Blvd, Memphis, TN 38105, USA
| | - David J Solecki
- Department of Developmental Neurobiology, St Jude Children's Research Hospital, 262 Danny Thomas Blvd, Memphis, TN 38105, USA.
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12
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Stick R, Dráber P. Editorial. PROTOPLASMA 2017; 254:1141-1142. [PMID: 28299513 DOI: 10.1007/s00709-017-1093-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Accepted: 02/22/2017] [Indexed: 06/06/2023]
Affiliation(s)
- Reimer Stick
- Institut für Zellbiologie, University of Bremen, Fachbereich 2, 28359, Bremen, Germany.
| | - Pavel Dráber
- Academy of Sciences of the Czech Republic, 142 20, Prague 4, Czech Republic
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