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Šterk M, Zhang Y, Pohorec V, Leitgeb EP, Dolenšek J, Benninger RKP, Stožer A, Kravets V, Gosak M. Network representation of multicellular activity in pancreatic islets: Technical considerations for functional connectivity analysis. PLoS Comput Biol 2024; 20:e1012130. [PMID: 38739680 PMCID: PMC11115366 DOI: 10.1371/journal.pcbi.1012130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2024] [Revised: 05/23/2024] [Accepted: 05/02/2024] [Indexed: 05/16/2024] Open
Abstract
Within the islets of Langerhans, beta cells orchestrate synchronized insulin secretion, a pivotal aspect of metabolic homeostasis. Despite the inherent heterogeneity and multimodal activity of individual cells, intercellular coupling acts as a homogenizing force, enabling coordinated responses through the propagation of intercellular waves. Disruptions in this coordination are implicated in irregular insulin secretion, a hallmark of diabetes. Recently, innovative approaches, such as integrating multicellular calcium imaging with network analysis, have emerged for a quantitative assessment of the cellular activity in islets. However, different groups use distinct experimental preparations, microscopic techniques, apply different methods to process the measured signals and use various methods to derive functional connectivity patterns. This makes comparisons between findings and their integration into a bigger picture difficult and has led to disputes in functional connectivity interpretations. To address these issues, we present here a systematic analysis of how different approaches influence the network representation of islet activity. Our findings show that the choice of methods used to construct networks is not crucial, although care is needed when combining data from different islets. Conversely, the conclusions drawn from network analysis can be heavily affected by the pre-processing of the time series, the type of the oscillatory component in the signals, and by the experimental preparation. Our tutorial-like investigation aims to resolve interpretational issues, reconcile conflicting views, advance functional implications, and encourage researchers to adopt connectivity analysis. As we conclude, we outline challenges for future research, emphasizing the broader applicability of our conclusions to other tissues exhibiting complex multicellular dynamics.
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Affiliation(s)
- Marko Šterk
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Yaowen Zhang
- Department of Pediatrics, Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
| | - Viljem Pohorec
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | | | - Jurij Dolenšek
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Richard K. P. Benninger
- Department of Bioengineering, Barbara Davis Center for Diabetes, Aurora, Colorado, United States of America
- Barbara Davis Center for Childhood Diabetes, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Andraž Stožer
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Vira Kravets
- Department of Pediatrics, Department of Bioengineering, University of California, San Diego, La Jolla, California, United States of America
- Department of Bioengineering, Jacobs School of Engineering, University of California, San Diego, La Jolla, California, United States of America
| | - Marko Gosak
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Alma Mater Europaea, Maribor
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2
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Liu Y, Zhang Y, Chang X, Liu X. MDIC3: Matrix decomposition to infer cell-cell communication. PATTERNS (NEW YORK, N.Y.) 2024; 5:100911. [PMID: 38370122 PMCID: PMC10873161 DOI: 10.1016/j.patter.2023.100911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 05/31/2023] [Accepted: 12/08/2023] [Indexed: 02/20/2024]
Abstract
Crosstalk among cells is vital for maintaining the biological function and intactness of systems. Most existing methods for investigating cell-cell communications are based on ligand-receptor (L-R) expression, and they focus on the study between two cells. Thus, the final communication inference results are particularly sensitive to the completeness and accuracy of the prior biological knowledge. Because existing L-R research focuses mainly on humans, most existing methods can only examine cell-cell communication for humans. As far as we know, there is currently no effective method to overcome this species limitation. Here, we propose MDIC3 (matrix decomposition to infer cell-cell communication), an unsupervised tool to investigate cell-cell communication in any species, and the results are not limited by specific L-R pairs or signaling pathways. By comparing it with existing methods for the inference of cell-cell communication, MDIC3 obtained better performance in both humans and mice.
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Affiliation(s)
- Yi Liu
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
- School of Mathematics and Statistics, Shandong University, Weihai 364209, China
| | - Yuelei Zhang
- School of Mathematics and Statistics, Shandong University, Weihai 364209, China
| | - Xiao Chang
- Institute of Statistics and Applied Mathematics, Anhui University of Finance and Economics, Bengbu 233030, China
| | - Xiaoping Liu
- Key Laboratory of Systems Health Science of Zhejiang Province, School of Life Science, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
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3
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Qi C, Lavriha P, Bayraktar E, Vaithia A, Schuster D, Pannella M, Sala V, Picotti P, Bortolozzi M, Korkhov VM. Structures of wild-type and selected CMT1X mutant connexin 32 gap junction channels and hemichannels. SCIENCE ADVANCES 2023; 9:eadh4890. [PMID: 37647412 PMCID: PMC10468125 DOI: 10.1126/sciadv.adh4890] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 07/27/2023] [Indexed: 09/01/2023]
Abstract
In myelinating Schwann cells, connection between myelin layers is mediated by gap junction channels (GJCs) formed by docked connexin 32 (Cx32) hemichannels (HCs). Mutations in Cx32 cause the X-linked Charcot-Marie-Tooth disease (CMT1X), a degenerative neuropathy without a cure. A molecular link between Cx32 dysfunction and CMT1X pathogenesis is still missing. Here, we describe the high-resolution cryo-electron cryo-myography (cryo-EM) structures of the Cx32 GJC and HC, along with two CMT1X-linked mutants, W3S and R22G. While the structures of wild-type and mutant GJCs are virtually identical, the HCs show a major difference: In the W3S and R22G mutant HCs, the amino-terminal gating helix partially occludes the pore, consistent with a diminished HC activity. Our results suggest that HC dysfunction may be involved in the pathogenesis of CMT1X.
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Affiliation(s)
- Chao Qi
- Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland
| | - Pia Lavriha
- Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland
| | - Erva Bayraktar
- Veneto Institute of Molecular Medicine (VIMM), Padua, Italy
- Department of Physics and Astronomy “G. Galilei”, University of Padua, Padua, Italy
| | - Anand Vaithia
- Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland
| | - Dina Schuster
- Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland
- Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
| | - Micaela Pannella
- Veneto Institute of Molecular Medicine (VIMM), Padua, Italy
- Department of Physics and Astronomy “G. Galilei”, University of Padua, Padua, Italy
| | - Valentina Sala
- Veneto Institute of Molecular Medicine (VIMM), Padua, Italy
| | - Paola Picotti
- Institute of Molecular Systems Biology, ETH Zurich, Zurich, Switzerland
| | - Mario Bortolozzi
- Veneto Institute of Molecular Medicine (VIMM), Padua, Italy
- Department of Physics and Astronomy “G. Galilei”, University of Padua, Padua, Italy
| | - Volodymyr M. Korkhov
- Institute of Molecular Biology and Biophysics, ETH Zurich, Zurich, Switzerland
- Laboratory of Biomolecular Research, Paul Scherrer Institute, Villigen, Switzerland
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4
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Hali M, Wadzinski BE, Kowluru A. Alpha4 contributes to the dysfunction of the pancreatic beta cell under metabolic stress. Mol Cell Endocrinol 2022; 557:111754. [PMID: 35987388 PMCID: PMC9620510 DOI: 10.1016/j.mce.2022.111754] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 08/10/2022] [Accepted: 08/12/2022] [Indexed: 11/30/2022]
Abstract
The current study examined the roles of Alpha4, a non-canonical subunit of protein phosphatase 2A, in the regulation of acute (insulin secretion) and chronic (cell dysfunction) effects of glucose in pancreatic beta cells. Alpha4 is expressed in human islets, rat islets and INS-1832/13 cells. Incubation of INS-1832/13 cells and rat islets with high glucose (HG) significantly increased the expression of Alpha4. C2-Ceramide, a biologically active sphingolipid, also increased the expression of Alpha4 in INS-1832/13 cells and rat islets. Subcellular distribution studies of Alpha4 in low glucose (LG) and HG exposed INS-1832/13 cells revealed that it is predominantly cytosolic, and its expression is significantly increased in the non-nuclear/cytosolic fractions in cells exposed to HG. siRNA-mediated knockdown of Alpha4 exerted minimal effects on glucose- or KCl-induced insulin secretion. siRNA-mediated deletion of Alpha4 significantly increased p38MAPK and JNK1/2 phosphorylation under LG conditions, comparable to the degree seen under HG conditions. Paradoxically, a significant potentiation of HG-induced p38MAPK and JNK2 phosphorylation was noted following Alpha4 deletion. HG-induced CHOP expression (ER stress marker) and caspase-3 activation were markedly attenuated in cells following Alpha4 knockdown. Deletion of Alpha4 in INS-1832/13 cells prevented HG-induced loss in the expression of Connexin36, a gap junction channel protein, which has been implicated in normal beta cell function. Lastly, depletion of endogenous Alpha4 significantly reduced HG-induced cell death in INS-1832/13 cells. Based on these findings we conclude that Alpha4 contributes to HG-induced metabolic dysfunction of the islet beta cell.
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Affiliation(s)
- Mirabela Hali
- Biomedical Research Service, John D. Dingell VA Medical Center, Detroit, MI, USA; Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, USA
| | - Brian E Wadzinski
- Department of Pharmacology, Vanderbilt University School of Medicine, Nashville, TN, 37232, USA
| | - Anjaneyulu Kowluru
- Biomedical Research Service, John D. Dingell VA Medical Center, Detroit, MI, USA; Department of Pharmaceutical Sciences, Eugene Applebaum College of Pharmacy and Health Sciences, Wayne State University, Detroit, MI, USA.
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Maxwell RW, Katyal S. Characteristics of Kundalini-Related Sensory, Motor, and Affective Experiences During Tantric Yoga Meditation. Front Psychol 2022; 13:863091. [PMID: 35846598 PMCID: PMC9282169 DOI: 10.3389/fpsyg.2022.863091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 04/27/2022] [Indexed: 12/21/2022] Open
Abstract
Traditional spiritual literature contains rich anecdotal reports of spontaneously arising experiences occurring during meditation practice, but formal investigation of such experiences is limited. Previous work has sometimes related spontaneous experiences to the Indian traditional contemplative concept of kundalini. Historically, descriptions of kundalini come out of Tantric schools of Yoga, where it has been described as a “rising energy” moving within the spinal column up to the brain. Spontaneous meditation experiences have previously been studied within Buddhist and Christian practices and within eclectic groups of contemplative practitioners. Prior explorations of kundalini have emphasized extreme experiences, sometimes having clinical consequences. We conducted a first such investigation of kundalini-related experiences within a sample of meditators from a single Tantric Yoga tradition (known as Ananda Marga) that emphasizes the role of kundalini. We developed a semi-structured questionnaire to conduct an exploratory pilot investigation of spontaneous sensory, motor and affective experiences during meditation practice. In addition to identifying the characteristics of subjective experiences, we measured quantity of meditation, supplemental practices, trait affect and trait mindfulness. We administered it to 80 volunteers at two Ananda Marga retreats. Among reported experiences, we found the highest prevalence for positive mood shifts, followed by motor and then sensory experiences. The frequency of spontaneous experiences was not related to the quantity of practiced meditation or trait measures of mindfulness and affect. Self-reports included multiple descriptions of rising sensations, sometimes being directly called kundalini. Experiences with rising sensations were complex and many included references to positive affect, including ecstatic qualities. There were also reports of spontaneous anomalous experiences. These experiences of rising sensations resemble prior clinical descriptions that were considered kundalini-related. The individuals who reported rising sensations could not be distinguished from other participants based on the incidence of experiences, quantity of meditation practice, or trait measures of mindfulness and affect. In contrast, greater amount of Tantric Yoga meditation practice was associated with greater positive affect, less negative affect and greater mindfulness. Further study of these exploratory findings and how they may be related to spiritual and well-being goals of meditation is warranted along with scientific investigation of purported kundalini phenomena.
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Affiliation(s)
- Richard W. Maxwell
- Private Practitioner, Ithaca, NY, United States
- *Correspondence: Richard W. Maxwell,
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6
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Zhang D, Hugo W, Bergsneider M, Wang MB, Kim W, Vinters HV, Heaney AP. Single-cell RNA sequencing in silent corticotroph tumors confirms impaired POMC processing and provides new insights into their invasive behavior. Eur J Endocrinol 2022; 187:49-64. [PMID: 35521707 PMCID: PMC9248914 DOI: 10.1530/eje-21-1183] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 04/21/2022] [Indexed: 11/08/2022]
Abstract
Objective Provide insights into the defective POMC processing and invasive behavior in silent pituitary corticotroph tumors. Design and methods Single-cell RNAseq was used to compare the cellular makeup and transcriptome of silent and active corticotroph tumors. Results A series of transcripts related to hormone processing peptidases and genes involved in the structural organization of secretory vesicles were reduced in silent compared to active corticotroph tumors. Most relevant to their invasive behavior, silent corticotroph tumors exhibited several features of epithelial-to-mesenchymal transition, with increased expression of mesenchymal genes along with the loss of transcripts that regulate hormonal biogenesis and secretion. Silent corticotroph tumor vascular smooth muscle cell and pericyte stromal cell populations also exhibited plasticity in their mesenchymal features. Conclusions Our findings provide novel insights into the mechanisms of impaired POMC processing and invasion in silent corticotroph tumors and suggest that a common transcriptional reprogramming mechanism simultaneously impairs POMC processing and activates tumor invasion.
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Affiliation(s)
- Dongyun Zhang
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles
| | - Willy Hugo
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles
| | - Marvin Bergsneider
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles
| | - Marilene B. Wang
- Department of Head and Neck Surgery, David Geffen School of Medicine, University of California, Los Angeles
| | - Won Kim
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles
| | - Harry V. Vinters
- Department of Pathology and Lab Medicine, David Geffen School of Medicine, University of California, Los Angeles
| | - Anthony P. Heaney
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles
- Department of Neurosurgery, David Geffen School of Medicine, University of California, Los Angeles
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7
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Collares-Buzato CB, Carvalho CP. Is type 2 diabetes mellitus another intercellular junction-related disorder? Exp Biol Med (Maywood) 2022; 247:743-755. [PMID: 35466731 DOI: 10.1177/15353702221090464] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Type 2 diabetes mellitus (T2D) is nowadays a worldwide epidemic and has become a major challenge for health systems around the world. It is a multifactorial disorder, characterized by a chronic state of hyperglycemia caused by defects in the production as well as in the peripheral action of insulin. This minireview highlights the experimental and clinical evidence that supports the novel idea that intercellular junctions (IJs)-mediated cell-cell contacts play a role in the pathogenesis of T2D. It focuses on IJs repercussion for endocrine pancreas, intestinal barrier, and kidney dysfunctions that contribute to the onset and evolution of this metabolic disorder.
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Affiliation(s)
- Carla B Collares-Buzato
- Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (UNICAMP), Campinas, SP, CEP 13083-970, Brazil
| | - Carolina Pf Carvalho
- Department of Biosciences, Federal University of São Paulo (UNIFESP), Santos, SP, CEP 11015-020, Brazil
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8
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Guérineau NC, Campos P, Le Tissier PR, Hodson DJ, Mollard P. Cell Networks in Endocrine/Neuroendocrine Gland Function. Compr Physiol 2022; 12:3371-3415. [PMID: 35578964 DOI: 10.1002/cphy.c210031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Reproduction, growth, stress, and metabolism are determined by endocrine/neuroendocrine systems that regulate circulating hormone concentrations. All these systems generate rhythms and changes in hormone pulsatility observed in a variety of pathophysiological states. Thus, the output of endocrine/neuroendocrine systems must be regulated within a narrow window of effective hormone concentrations but must also maintain a capacity for plasticity to respond to changing physiological demands. Remarkably most endocrinologists still have a "textbook" view of endocrine gland organization which has emanated from 20th century histological studies on thin 2D tissue sections. However, 21st -century technological advances, including in-depth 3D imaging of specific cell types have vastly changed our knowledge. We now know that various levels of multicellular organization can be found across different glands, that organizational motifs can vary between species and can be modified to enhance or decrease hormonal release. This article focuses on how the organization of cells regulates hormone output using three endocrine/neuroendocrine glands that present different levels of organization and complexity: the adrenal medulla, with a single neuroendocrine cell type; the anterior pituitary, with multiple intermingled cell types; and the pancreas with multiple intermingled cell types organized into distinct functional units. We give an overview of recent methodologies that allow the study of the different components within endocrine systems, particularly their temporal and spatial relationships. We believe the emerging findings about network organization, and its impact on hormone secretion, are crucial to understanding how homeostatic regulation of endocrine axes is carried out within endocrine organs themselves. © 2022 American Physiological Society. Compr Physiol 12:3371-3415, 2022.
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Affiliation(s)
| | - Pauline Campos
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, UK
| | - Paul R Le Tissier
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, Scotland, UK
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Edgbaston, UK.,Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham, UK.,COMPARE University of Birmingham and University of Nottingham Midlands, UK.,Oxford Centre for Diabetes, Endocrinology and Metabolism (OCDEM), NIHR Oxford Biomedical Research Centre, Churchill Hospital, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Patrice Mollard
- IGF, University of Montpellier, CNRS, INSERM, Montpellier, France
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9
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Chen YY, Chen WL. The relationship between polycyclic aromatic hydrocarbons exposure and serum klotho among adult population. BMC Geriatr 2022; 22:198. [PMID: 35287592 PMCID: PMC8919518 DOI: 10.1186/s12877-022-02924-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Accepted: 03/09/2022] [Indexed: 01/17/2023] Open
Abstract
Background Klotho is an important factor involving aging process. Recently, polycyclic aromatic hydrocarbons (PAHs) exposure was reported to have adverse impact on DNA methylation associated with aging. The aim of the current study was to determine the relationship between serum klotho and PAHs exposure in an adult population. Methods A total of 2597 participants obtained from NHANES 2015–2016 were included in this cross-sectional study. Serum klotho levels were analyzed by enzyme-linked immunosorbent assay (ELISA). PAHs exposure was estimated by urinary sample using liquid chromatography-tandem mass spectrometry. The relationship between serum klotho and exposure to PAHS was analyzed by a multivariable linear regression model. Results 2-napthol and 3-fluorene were significantly associated with decreased klotho. After fully adjusting pertinent variables, PAH exposure was significantly associated with decreased klotho, particularly in men. Conclusion In the present study we highlighted the significant association between PAHs exposure and serum klotho levels. The importance of environmental effect on aging process and age-related disorders should be paid more attention and clinical intervention is necessary.
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Affiliation(s)
- Yuan-Yuei Chen
- Department of Pathology, Tri-Service General Hospital, and School of Medicine, National Defense Medical Center, Taipei, Taiwan, Republic of China.,Department of Pathology, Tri-Service General Hospital Songshan Branch, and School of Medicine, National Defense Medical Center, Taipei, Taiwan, Republic of China
| | - Wei-Liang Chen
- Division of Geriatric Medicine, Department of Family and Community Medicine, Tri-Service General Hospital, and School of Medicine, National Defense Medical Center, Taipei, Taiwan, Republic of China. .,Department of Biochemistry, National Defense Medical Center, Taipei, Taiwan, Republic of China.
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10
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Stožer A, Šterk M, Paradiž Leitgeb E, Markovič R, Skelin Klemen M, Ellis CE, Križančić Bombek L, Dolenšek J, MacDonald PE, Gosak M. From Isles of Königsberg to Islets of Langerhans: Examining the Function of the Endocrine Pancreas Through Network Science. Front Endocrinol (Lausanne) 2022; 13:922640. [PMID: 35784543 PMCID: PMC9240343 DOI: 10.3389/fendo.2022.922640] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 05/16/2022] [Indexed: 12/12/2022] Open
Abstract
Islets of Langerhans are multicellular microorgans located in the pancreas that play a central role in whole-body energy homeostasis. Through secretion of insulin and other hormones they regulate postprandial storage and interprandial usage of energy-rich nutrients. In these clusters of hormone-secreting endocrine cells, intricate cell-cell communication is essential for proper function. Electrical coupling between the insulin-secreting beta cells through gap junctions composed of connexin36 is particularly important, as it provides the required, most important, basis for coordinated responses of the beta cell population. The increasing evidence that gap-junctional communication and its modulation are vital to well-regulated secretion of insulin has stimulated immense interest in how subpopulations of heterogeneous beta cells are functionally arranged throughout the islets and how they mediate intercellular signals. In the last decade, several novel techniques have been proposed to assess cooperation between cells in islets, including the prosperous combination of multicellular imaging and network science. In the present contribution, we review recent advances related to the application of complex network approaches to uncover the functional connectivity patterns among cells within the islets. We first provide an accessible introduction to the basic principles of network theory, enumerating the measures characterizing the intercellular interactions and quantifying the functional integration and segregation of a multicellular system. Then we describe methodological approaches to construct functional beta cell networks, point out possible pitfalls, and specify the functional implications of beta cell network examinations. We continue by highlighting the recent findings obtained through advanced multicellular imaging techniques supported by network-based analyses, giving special emphasis to the current developments in both mouse and human islets, as well as outlining challenges offered by the multilayer network formalism in exploring the collective activity of islet cell populations. Finally, we emphasize that the combination of these imaging techniques and network-based analyses does not only represent an innovative concept that can be used to describe and interpret the physiology of islets, but also provides fertile ground for delineating normal from pathological function and for quantifying the changes in islet communication networks associated with the development of diabetes mellitus.
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Affiliation(s)
- Andraž Stožer
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Marko Šterk
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
| | - Eva Paradiž Leitgeb
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Rene Markovič
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- Institute of Mathematics and Physics, Faculty of Electrical Engineering and Computer Science, University of Maribor, Maribor, Slovenia
| | - Maša Skelin Klemen
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
| | - Cara E. Ellis
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | | | - Jurij Dolenšek
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
| | - Patrick E. MacDonald
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - Marko Gosak
- Institute of Physiology, Faculty of Medicine, University of Maribor, Maribor, Slovenia
- Department of Physics, Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
- *Correspondence: Marko Gosak,
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11
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Benninger RKP, Kravets V. The physiological role of β-cell heterogeneity in pancreatic islet function. Nat Rev Endocrinol 2022; 18:9-22. [PMID: 34667280 PMCID: PMC8915749 DOI: 10.1038/s41574-021-00568-0] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/07/2021] [Indexed: 01/03/2023]
Abstract
Endocrine cells within the pancreatic islets of Langerhans are heterogeneous in terms of transcriptional profile, protein expression and the regulation of hormone release. Even though this heterogeneity has long been appreciated, only within the past 5 years have detailed molecular analyses led to an improved understanding of its basis. Although we are beginning to recognize why some subpopulations of endocrine cells are phenotypically different to others, arguably the most important consideration is how this heterogeneity affects the regulation of hormone release to control the homeostasis of glucose and other energy-rich nutrients. The focus of this Review is the description of how endocrine cell heterogeneity (and principally that of insulin-secreting β-cells) affects the regulation of hormone secretion within the islets of Langerhans. This discussion includes an overview of the functional characteristics of the different islet cell subpopulations and describes how they can communicate to influence islet function under basal and glucose-stimulated conditions. We further discuss how changes to the specific islet cell subpopulations or their numbers might underlie islet dysfunction in type 2 diabetes mellitus. We conclude with a discussion of several key open questions regarding the physiological role of islet cell heterogeneity.
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Affiliation(s)
- Richard K P Benninger
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
| | - Vira Kravets
- Department of Bioengineering, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Medical Campus, Aurora, CO, USA.
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12
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Title AC, Silva PN, Godbersen S, Hasenöhrl L, Stoffel M. The miR-200-Zeb1 axis regulates key aspects of β-cell function and survival in vivo. Mol Metab 2021; 53:101267. [PMID: 34116231 PMCID: PMC8258987 DOI: 10.1016/j.molmet.2021.101267] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/24/2021] [Accepted: 06/03/2021] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVE The miR-200-Zeb1 axis regulates the epithelial-to-mesenchymal transition (EMT), differentiation, and resistance to apoptosis. A better understanding of these processes in diabetes is highly relevant, as β-cell dedifferentiation and apoptosis contribute to the loss of functional β-cell mass and diabetes progression. Furthermore, EMT promotes the loss of β-cell identity in the in vitro expansion of human islets. Though the miR-200 family has previously been identified as a regulator of β-cell apoptosis in vivo, studies focusing on Zeb1 are lacking. The aim of this study was thus to investigate the role of Zeb1 in β-cell function and survival in vivo. METHODS miR-200 and Zeb1 are involved in a double-negative feedback loop. We characterized a mouse model in which miR-200 binding sites in the Zeb1 3'UTR are mutated (Zeb1200), leading to a physiologically relevant upregulation of Zeb1 mRNA expression. The role of Zeb1 was investigated in this model via metabolic tests and analysis of isolated islets. Further insights into the distinct contributions of the miR-200 and Zeb1 branches of the feedback loop were obtained by crossing the Zeb1200 allele into a background of miR-141-200c overexpression. RESULTS Mild Zeb1 derepression in vivo led to broad transcriptional changes in islets affecting β-cell identity, EMT, insulin secretion, cell-cell junctions, the unfolded protein response (UPR), and the response to ER stress. The aggregation and insulin secretion of dissociated islets of mice homozygous for the Zeb1200 mutation (Zeb1200M) were impaired, and Zeb1200M islets were resistant to thapsigargin-induced ER stress ex vivo. Zeb1200M mice had increased circulating proinsulin levels but no overt metabolic phenotype, reflecting the strong compensatory ability of islets to maintain glucose homeostasis. CONCLUSIONS This study signifies the importance of the miR-200-Zeb1 axis in regulating key aspects of β-cell function and survival. A better understanding of this axis is highly relevant in developing therapeutic strategies for inducing β-cell redifferentiation and maintaining β-cell identity in in vitro islet expansion.
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Affiliation(s)
- Alexandra C Title
- Institute of Molecular Health Sciences (IMHS), ETH Zürich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland; Competence Center Personalized Medicine, ETH Zürich, Voltastrasse 24, 8044, Zürich, Switzerland
| | - Pamuditha N Silva
- Institute of Molecular Health Sciences (IMHS), ETH Zürich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland
| | - Svenja Godbersen
- Institute of Molecular Health Sciences (IMHS), ETH Zürich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland
| | - Lynn Hasenöhrl
- Institute of Molecular Health Sciences (IMHS), ETH Zürich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland
| | - Markus Stoffel
- Institute of Molecular Health Sciences (IMHS), ETH Zürich, Otto-Stern-Weg 7, 8093, Zürich, Switzerland; Competence Center Personalized Medicine, ETH Zürich, Voltastrasse 24, 8044, Zürich, Switzerland; Medical Faculty, University of Zürich, 8091, Zürich, Switzerland.
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13
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Korošak D, Jusup M, Podobnik B, Stožer A, Dolenšek J, Holme P, Rupnik MS. Autopoietic Influence Hierarchies in Pancreatic β Cells. PHYSICAL REVIEW LETTERS 2021; 127:168101. [PMID: 34723613 DOI: 10.1103/physrevlett.127.168101] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2021] [Accepted: 09/09/2021] [Indexed: 06/13/2023]
Abstract
β cells are biologically essential for humans and other vertebrates. Because their functionality arises from cell-cell interactions, they are also a model system for collective organization among cells. There are currently two contradictory pictures of this organization: the hub-cell idea pointing at leaders who coordinate the others, and the electrophysiological theory describing all cells as equal. We use new data and computational modeling to reconcile these pictures. We find via a network representation of interacting β cells that leaders emerge naturally (confirming the hub-cell idea), yet all cells can take the hub role following a perturbation (in line with electrophysiology).
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Affiliation(s)
- Dean Korošak
- Institute of Physiology, Faculty of Medicine, University of Maribor, 2000 Maribor, Slovenia
- Faculty of Civil Engineering, Transportation Engineering and Architecture, University of Maribor, 2000 Maribor, Slovenia
| | - Marko Jusup
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 152-8552, Japan
| | - Boris Podobnik
- Faculty of Civil Engineering, University of Rijeka, 51000 Rijeka, Croatia
- Center for Polymer Studies, Boston University, Boston, Massachusetts 02215, USA
- Zagreb School of Economics and Management, 10000 Zagreb, Croatia
- Luxembourg School of Business, 2453 Luxembourg, Luxembourg
- Faculty of Information Studies in Novo mesto, 8000 Novo Mesto, Slovenia
| | - Andraž Stožer
- Institute of Physiology, Faculty of Medicine, University of Maribor, 2000 Maribor, Slovenia
| | - Jurij Dolenšek
- Institute of Physiology, Faculty of Medicine, University of Maribor, 2000 Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, 2000 Maribor, Slovenia
| | - Petter Holme
- Tokyo Tech World Research Hub Initiative (WRHI), Institute of Innovative Research, Tokyo Institute of Technology, Tokyo 152-8552, Japan
| | - Marjan Slak Rupnik
- Institute of Physiology, Faculty of Medicine, University of Maribor, 2000 Maribor, Slovenia
- Center for Physiology and Pharmacology, Medical University of Vienna, 1090 Vienna, Austria
- Alma Mater Europaea-European Center Maribor, 2000 Maribor, Slovenia
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14
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Stožer A, Skelin Klemen M, Gosak M, Križančić Bombek L, Pohorec V, Slak Rupnik M, Dolenšek J. Glucose-dependent activation, activity, and deactivation of beta cell networks in acute mouse pancreas tissue slices. Am J Physiol Endocrinol Metab 2021; 321:E305-E323. [PMID: 34280052 DOI: 10.1152/ajpendo.00043.2021] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Accepted: 07/09/2021] [Indexed: 12/14/2022]
Abstract
Many details of glucose-stimulated intracellular calcium changes in β cells during activation, activity, and deactivation, as well as their concentration-dependence, remain to be analyzed. Classical physiological experiments indicated that in islets, functional differences between individual cells are largely attenuated, but recent findings suggest considerable intercellular heterogeneity, with some cells possibly coordinating the collective responses. To address the above with an emphasis on heterogeneity and describing the relations between classical physiological and functional network properties, we performed functional multicellular calcium imaging in mouse pancreas tissue slices over a wide range of glucose concentrations. During activation, delays to activation of cells and any-cell-to-first-responder delays are shortened, and the sizes of simultaneously responding clusters increased with increasing glucose concentrations. Exactly the opposite characterized deactivation. The frequency of fast calcium oscillations during activity increased with increasing glucose up to 12 mM glucose concentration, beyond which oscillation duration became longer, resulting in a homogenous increase in active time. In terms of functional connectivity, islets progressed from a very segregated network to a single large functional unit with increasing glucose concentration. A comparison between classical physiological and network parameters revealed that the first-responders during activation had longer active times during plateau and the most active cells during the plateau tended to deactivate later. Cells with the most functional connections tended to activate sooner, have longer active times, and deactivate later. Our findings provide a common ground for recent differing views on β cell heterogeneity and an important baseline for future studies of stimulus-secretion and intercellular coupling.NEW & NOTEWORTHY We assessed concentration-dependence in coupled β cells, degree of functional heterogeneity, and uncovered possible specialized subpopulations during the different phases of the response to glucose at the level of many individual cells. To this aim, we combined acute mouse pancreas tissue slices with functional multicellular calcium imaging over a wide range from threshold (7 mM) and physiological (8 and 9 mM) to supraphysiological (12 and 16 mM) glucose concentrations, classical physiological, and advanced network analyses.
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Affiliation(s)
- Andraž Stožer
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
| | - Maša Skelin Klemen
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
| | - Marko Gosak
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
| | | | - Viljem Pohorec
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
| | - Marjan Slak Rupnik
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- Alma Mater Europaea-European Center Maribor, Maribor, Slovenia
| | - Jurij Dolenšek
- Faculty of Medicine, Institute of Physiology, University of Maribor, Maribor, Slovenia
- Faculty of Natural Sciences and Mathematics, University of Maribor, Maribor, Slovenia
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15
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Ouabain Enhances Gap Junctional Intercellular Communication by Inducing Paracrine Secretion of Prostaglandin E2. Int J Mol Sci 2021; 22:ijms22126244. [PMID: 34200582 PMCID: PMC8230150 DOI: 10.3390/ijms22126244] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 05/28/2021] [Accepted: 06/04/2021] [Indexed: 12/27/2022] Open
Abstract
Ouabain is a cardiac glycoside that has been described as a hormone, with interesting effects on epithelial physiology. We have shown previously that ouabain induces gap junctional intercellular communication (GJIC) in wild, sensitive cells (MDCK-S), but not in cells that have become insensitive (MDCK-I) by modifying their Na+-K+-ATPase. We have also demonstrated that prostaglandin E2 (PGE2) is able to induce increased GJIC by a mechanism other than ouabain, that does not depend on Na+-K+-ATPase. In this work we show, by dye transfer assays, that when MDCK-S and MDCK-I are randomly mixed, to form monolayers, the latter stablish GJIC, because of stimulation by a compound released to the extracellular media, by MDCK-S cells, after treatment with ouabain, as evidenced by the fact that monolayers of only MDCK-I cells, treated with a conditioned medium (CM) that is obtained after incubation of MDCK-S monolayers with ouabain, significantly increase their GJIC. The further finding that either (1) pre-treatment with COX-2 inhibitors or (2) addition to CM of antagonists of EP2 receptor abolish CM's ability to induce GJIC in MDCK-I monolayers indicate that PGE2 is the GJIC-inducing compound. Therefore, these results indicate that, in addition to direct stimulation, mediated by Na+-K+-ATPase, ouabain enhances GJIC indirectly through the paracrine production of PGE2.
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16
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Ogazon del Toro A, Jimenez L, Serrano Rubi M, Castillo A, Hinojosa L, Martinez Rendon J, Cereijido M, Ponce A. Prostaglandin E2 Enhances Gap Junctional Intercellular Communication in Clonal Epithelial Cells. Int J Mol Sci 2021; 22:5813. [PMID: 34071686 PMCID: PMC8198183 DOI: 10.3390/ijms22115813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/30/2021] [Accepted: 03/30/2021] [Indexed: 12/12/2022] Open
Abstract
Prostaglandins are a group of lipids that produce diverse physiological and pathological effects. Among them, prostaglandin E2 (PGE2) stands out for the wide variety of functions in which it participates. To date, there is little information about the influence of PGE2 on gap junctional intercellular communication (GJIC) in any type of tissue, including epithelia. In this work, we set out to determine whether PGE2 influences GJIC in epithelial cells (MDCK cells). To this end, we performed dye (Lucifer yellow) transfer assays to compare GJIC of MDCK cells treated with PGE2 and untreated cells. Our results indicated that (1) PGE2 induces a statistically significant increase in GJIC from 100 nM and from 15 min after its addition to the medium, (2) such effect does not require the synthesis of new mRNA or proteins subunits but rather trafficking of subunits already synthesized, and (3) such effect is mediated by the E2 receptor, which, in turn, triggers a signaling pathway that includes activation of adenylyl cyclase and protein kinase A (PKA). These results widen the knowledge regarding modulation of gap junctional intercellular communication by prostaglandins.
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Affiliation(s)
| | | | | | | | | | | | | | - Arturo Ponce
- Department of Physiology, Biophysics and Neurosciences, CINVESTAV-IPN, CDMX, México C.P. 07360, Mexico; (A.O.d.T.); (L.J.); (M.S.R.); (A.C.); (L.H.); (J.M.R.); (M.C.)
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17
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Friedlander MSH, Nguyen VM, Kim SK, Bevacqua RJ. Pancreatic Pseudoislets: An Organoid Archetype for Metabolism Research. Diabetes 2021; 70:1051-1060. [PMID: 33947722 PMCID: PMC8343609 DOI: 10.2337/db20-1115] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2020] [Accepted: 02/20/2021] [Indexed: 01/08/2023]
Abstract
Pancreatic islets are vital endocrine regulators of systemic metabolism, and recent investigations have increasingly focused on understanding human islet biology. Studies of isolated human islets have advanced understanding of the development, function, and regulation of cells comprising islets, especially pancreatic α- and β-cells. However, the multicellularity of the intact islet has stymied specific experimental approaches-particularly in genetics and cell signaling interrogation. This barrier has been circumvented by the observation that islet cells can survive dispersion and reaggregate to form "pseudoislets," organoids that retain crucial physiological functions, including regulated insulin and glucagon secretion. Recently, exciting advances in the use of pseudoislets for genetics, genomics, islet cell transplantation, and studies of intraislet signaling and islet cell interactions have been reported by investigators worldwide. Here we review molecular and cellular mechanisms thought to promote islet cell reaggregation, summarize methods that optimize pseudoislet development, and detail recent insights about human islet biology from genetic and transplantation-based pseudoislet experiments. Owing to robust, international programs for procuring primary human pancreata, pseudoislets should serve as both a durable paradigm for primary organoid studies and as an engine of discovery for islet biology, diabetes, and metabolism research.
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Affiliation(s)
- Mollie S H Friedlander
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA
| | - Vy M Nguyen
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA
| | - Seung K Kim
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA
- Department of Medicine, Stanford University School of Medicine, Stanford, CA
- Stanford Diabetes Research Center, Stanford University School of Medicine, Stanford, CA
- JDRF Center of Excellence, Stanford University School of Medicine, Stanford, CA
| | - Romina J Bevacqua
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA
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18
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Garcia-Vega L, O’Shaughnessy EM, Albuloushi A, Martin PE. Connexins and the Epithelial Tissue Barrier: A Focus on Connexin 26. BIOLOGY 2021; 10:biology10010059. [PMID: 33466954 PMCID: PMC7829877 DOI: 10.3390/biology10010059] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Revised: 01/11/2021] [Accepted: 01/12/2021] [Indexed: 12/15/2022]
Abstract
Simple Summary Tissues that face the external environment are known as ‘epithelial tissue’ and form barriers between different body compartments. This includes the outer layer of the skin, linings of the intestine and airways that project into the lumen connecting with the external environment, and the cornea of the eye. These tissues do not have a direct blood supply and are dependent on exchange of regulatory molecules between cells to ensure co-ordination of tissue events. Proteins known as connexins form channels linking cells directly and permit exchange of small regulatory signals. A range of environmental stimuli can dysregulate the level of connexin proteins and or protein function within the epithelia, leading to pathologies including non-healing wounds. Mutations in these proteins are linked with hearing loss, skin and eye disorders of differing severity. As such, connexins emerge as prime therapeutic targets with several agents currently in clinical trials. This review outlines the role of connexins in epithelial tissue and how their dysregulation contributes to pathological pathways. Abstract Epithelial tissue responds rapidly to environmental triggers and is constantly renewed. This tissue is also highly accessible for therapeutic targeting. This review highlights the role of connexin mediated communication in avascular epithelial tissue. These proteins form communication conduits with the extracellular space (hemichannels) and between neighboring cells (gap junctions). Regulated exchange of small metabolites less than 1kDa aide the co-ordination of cellular activities and in spatial communication compartments segregating tissue networks. Dysregulation of connexin expression and function has profound impact on physiological processes in epithelial tissue including wound healing. Connexin 26, one of the smallest connexins, is expressed in diverse epithelial tissue and mutations in this protein are associated with hearing loss, skin and eye conditions of differing severity. The functional consequences of dysregulated connexin activity is discussed and the development of connexin targeted therapeutic strategies highlighted.
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19
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Liu W, Cui Y, Wei J, Sun J, Zheng L, Xie J. Gap junction-mediated cell-to-cell communication in oral development and oral diseases: a concise review of research progress. Int J Oral Sci 2020; 12:17. [PMID: 32532966 PMCID: PMC7293327 DOI: 10.1038/s41368-020-0086-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Revised: 04/30/2020] [Accepted: 05/19/2020] [Indexed: 02/05/2023] Open
Abstract
Homoeostasis depends on the close connection and intimate molecular exchange between extracellular, intracellular and intercellular networks. Intercellular communication is largely mediated by gap junctions (GJs), a type of specialized membrane contact composed of variable number of channels that enable direct communication between cells by allowing small molecules to pass directly into the cytoplasm of neighbouring cells. Although considerable evidence indicates that gap junctions contribute to the functions of many organs, such as the bone, intestine, kidney, heart, brain and nerve, less is known about their role in oral development and disease. In this review, the current progress in understanding the background of connexins and the functions of gap junctions in oral development and diseases is discussed. The homoeostasis of tooth and periodontal tissues, normal tooth and maxillofacial development, saliva secretion and the integrity of the oral mucosa depend on the proper function of gap junctions. Knowledge of this pattern of cell-cell communication is required for a better understanding of oral diseases. With the ever-increasing understanding of connexins in oral diseases, therapeutic strategies could be developed to target these membrane channels in various oral diseases and maxillofacial dysplasia.
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Affiliation(s)
- Wenjing Liu
- State Key Laboratory of Oral Diseases & National Clinical Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yujia Cui
- State Key Laboratory of Oral Diseases & National Clinical Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jieya Wei
- State Key Laboratory of Oral Diseases & National Clinical Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jianxun Sun
- State Key Laboratory of Oral Diseases & National Clinical Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Liwei Zheng
- State Key Laboratory of Oral Diseases & National Clinical Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Jing Xie
- State Key Laboratory of Oral Diseases & National Clinical Center for Oral Diseases & West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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20
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Hamard L, Santoro T, Allagnat F, Meda P, Nardelli-Haefliger D, Alonso F, Haefliger JA. Targeting connexin37 alters angiogenesis and arteriovenous differentiation in the developing mouse retina. FASEB J 2020; 34:8234-8249. [PMID: 32323401 DOI: 10.1096/fj.202000257r] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 03/20/2020] [Accepted: 04/06/2020] [Indexed: 11/11/2022]
Abstract
Connexin37 (Cx37) forms intercellular channels between endothelial cells (EC), and contributes to coordinate the motor tone of vessels. We investigated the contribution of this protein during physiological angiogenesis. We show that, compared to WT littermates, mice lacking Cx37 (Cx37-/- ) featured (i) a decreased extension of the superficial vascular plexus during the first 4 days after birth; (ii) an increased vascular density at the angiogenic front at P6, due to an increase in the proliferative rate of EC and in the sprouting of the venous compartment, as well as to a somewhat displaced position of tip cells; (iii) a decreased coverage of newly formed arteries and veins by mural cells; (iv) altered ERK-dependent endothelial cells proliferation through the EphB4 signaling pathway, which is involved in the specification of veins and arteries. In vitro studies documented that, in the absence of Cx37, human venous EC (HUVEC) released less platelet-derived growth factor (PDGF) and more Angiopoietin-2, two molecules involved in the recruitment of mural cells. Treatment of mice with DAPT, an inhibitor of the Notch pathway, decreased the expression of Cx37, and partially mimicked in WT retinas, the alterations observed in Cx37-/- mice. Thus, Cx37 contributes to (i) the early angiogenesis of retina, by interacting with the Notch pathway; (ii) the growth and maturation of neo-vessels, by modulating tip, stalk, and mural cells; (iii) the regulation of arteriovenous specification, thus, representing a novel target for treatments of retina diseases.
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Affiliation(s)
- Lauriane Hamard
- Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Tania Santoro
- Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Florent Allagnat
- Department of Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Paolo Meda
- Department of Cell Physiology and Metabolism, Medical Center, University of Geneva, Geneva, Switzerland
| | | | - Florian Alonso
- Centre de Recherche Cardio-Thoracique de Bordeaux (INSERM U1045), Université de Bordeaux, Bordeaux, France
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21
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Rodriguez-Diaz R, Tamayo A, Hara M, Caicedo A. The Local Paracrine Actions of the Pancreatic α-Cell. Diabetes 2020; 69:550-558. [PMID: 31882565 PMCID: PMC7085245 DOI: 10.2337/dbi19-0002] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 12/16/2019] [Indexed: 12/13/2022]
Abstract
Secretion of glucagon from the pancreatic α-cells is conventionally seen as the first and most important defense against hypoglycemia. Recent findings, however, show that α-cell signals stimulate insulin secretion from the neighboring β-cell. This article focuses on these seemingly counterintuitive local actions of α-cells and describes how they impact islet biology and glucose metabolism. It is mostly based on studies published in the last decade on the physiology of α-cells in human islets and incorporates results from rodents where appropriate. As this and the accompanying articles show, the emerging picture of α-cell function is one of increased complexity that needs to be considered when developing new therapies aimed at promoting islet function in the context of diabetes.
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Affiliation(s)
- Rayner Rodriguez-Diaz
- Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL
| | - Alejandro Tamayo
- Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL
| | - Manami Hara
- Department of Medicine, University of Chicago, Chicago, IL
| | - Alejandro Caicedo
- Department of Medicine, University of Miami Miller School of Medicine, Miami, FL
- Diabetes Research Institute, University of Miami Miller School of Medicine, Miami, FL
- Department of Physiology and Biophysics, University of Miami Miller School of Medicine, Miami, FL
- Program in Neuroscience, University of Miami Miller School of Medicine, Miami, FL
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22
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Lammert E, Thorn P. The Role of the Islet Niche on Beta Cell Structure and Function. J Mol Biol 2019; 432:1407-1418. [PMID: 31711959 DOI: 10.1016/j.jmb.2019.10.032] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/25/2019] [Accepted: 10/29/2019] [Indexed: 01/15/2023]
Abstract
The islets of Langerhans or pancreatic islets are pivotal in the control of blood glucose and are complex microorgans embedded within the larger volume of the exocrine pancreas. Humans can have ~3.2 million islets [1] which, to our current knowledge, function in a similar manner to sense circulating blood glucose levels and respond with the secretion of a mix of different hormones that act to maintain glucose concentrations around a specific set point [2]. At a cellular level, the control of hormone secretion by glucose and other secretagogues is well-understood [3]. The key signal cascades have been identified and many details of the secretory process are known. However, if we shift focus from single cells and consider cells within intact islets, we do not have a comprehensive model as to how the islet environment influences cell function and how the islets work as a whole. This is important because there is overwhelming evidence that the structure and function of the individual endocrine cells are dramatically affected by the islet environment [4,5]. Uncovering the influence of this islet niche might drive future progress in treatments for Type 2 diabetes [6] and cell replacement therapies for Type 1 diabetes [7]. In this review, we focus on the insulin secreting beta cells and their interactions with the immediate environment that surrounds them including endocrine-endocrine interactions and contacts with capillaries.
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Affiliation(s)
- Eckhard Lammert
- Institute of Metabolic Physiology, Heinrich Heine University, Düsseldorf, Germany; Institute for Vascular and Islet Cell Biology, German Diabetes Center, Leibniz Center for Diabetes Research, Heinrich Heine University, Düsseldorf, Germany; German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Peter Thorn
- Charles Perkins Centre, School of Medical Sciences, University of Sydney, Camperdown, NSW 2006, Australia.
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Sarrouilhe D, Mesnil M, Dejean C. Targeting Gap Junctions: New Insights into the Treatment of Major Depressive Disorder. Curr Med Chem 2019; 26:3775-3791. [DOI: 10.2174/0929867325666180327103530] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 12/22/2017] [Accepted: 03/21/2018] [Indexed: 01/05/2023]
Abstract
Background:Major depressive disorder (MDD) is a multifactorial chronic and debilitating mood disease with high lifetime prevalence and associated with excess mortality. Treatments for this disease are not effective in all patients showing the need to find new therapeutic targets.Objective:This review aims to update our knowledge on the involvement of astroglial gap junctions and hemichannels in MDD and to show how they have become potential targets for the treatment of this pathology.Methods:The method applied in this review includes a systematic compilation of the relevant literature.Results and Conclusion:The use of rodent models of depression, gene analysis of hippocampal tissues of MDD patients and post-mortem studies on the brains from MDD patients suggest that astrocytic gap junction dysfunction may be a part of MDD etiologies. Chronic antidepressant treatments of rats, rat cultured cortical astrocytes and human astrocytoma cell lines support the hypothesis that the up-regulation of gap junctional coupling between astrocytes could be an underlying mechanism for the therapeutic effect of antidepressants. However, two recent functional studies suggest that connexin43 hemichannel activity is a part of several antidepressants’ mode of action and that astrocyte gap junctional intercellular communication and hemichannels exert different effects on antidepressant drug response. Even if they emerge as new therapeutic targets for new and more active treatments, further studies are needed to decipher the sophisticated and respective role of astrocytic gap junctions and hemichannels in MDD.
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Affiliation(s)
- Denis Sarrouilhe
- Laboratoire de Physiologie Humaine, Faculte de Medecine et Pharmacie, Universite de Poitiers, 6 rue de la Miletrie, Bat D1, TSA 51115, 86073 Poitiers, Cedex 9, France
| | - Marc Mesnil
- STIM, ERL 7003, CNRS-Universite de Poitiers, Pole Biologie Sante, Bat B36, TSA 51106, 1 rue Georges Bonnet, 86073 Poitiers, Cedex 9, France
| | - Catherine Dejean
- Service Pharmacie, Pavillon Janet, Centre Hospitalier Henri Laborit, 370 avenue Jacques Coeur, 86021 Poitiers Cedex, France
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24
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Abstract
Controlling the excess and shortage of energy is a fundamental task for living organisms. Diabetes is a representative metabolic disease caused by the malfunction of energy homeostasis. The islets of Langerhans in the pancreas release long-range messengers, hormones, into the blood to regulate the homeostasis of the primary energy fuel, glucose. The hormone and glucose levels in the blood show rhythmic oscillations with a characteristic period of 5-10 min, and the functional roles of the oscillations are not clear. Each islet has [Formula: see text] and [Formula: see text] cells that secrete glucagon and insulin, respectively. These two counter-regulatory hormones appear sufficient to increase and decrease glucose levels. However, pancreatic islets have a third cell type, [Formula: see text] cells, which secrete somatostatin. The three cell populations have a unique spatial organization in islets, and they interact to perturb their hormone secretions. The mini-organs of islets are scattered throughout the exocrine pancreas. Considering that the human pancreas contains approximately a million islets, the coordination of hormone secretion from the multiple sources of islets and cells within the islets should have a significant effect on human physiology. In this review, we introduce the hierarchical organization of tripartite cell networks, and recent biophysical modeling to systematically understand the oscillations and interactions of [Formula: see text], [Formula: see text], and [Formula: see text] cells. Furthermore, we discuss the functional roles and clinical implications of hormonal oscillations and their phase coordination for the diagnosis of type II diabetes.
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Affiliation(s)
- Taegeun Song
- Department of Physics, Pohang University of Science and Technology, Pohang, Gyeongbuk 37673, Republic of Korea
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25
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Le Gal L, Pellegrin M, Santoro T, Mazzolai L, Kurtz A, Meda P, Wagner C, Haefliger J. Connexin37-Dependent Mechanisms Selectively Contribute to Modulate Angiotensin II -Mediated Hypertension. J Am Heart Assoc 2019; 8:e010823. [PMID: 30943815 PMCID: PMC6507190 DOI: 10.1161/jaha.118.010823] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 01/30/2019] [Indexed: 12/23/2022]
Abstract
Background Gap junction channels made of Connexin37 (Cx37) are expressed by aortic endothelial and smooth muscle cells of hypertensive mice, as well as by the renin-secreting cells of kidneys. Methods and Results To decipher whether Cx37 has any role in hypertension, angiotensin II (Ang II ) was infused in normotensive wild-type and Cx37-deficient mice (Cx37-/-). After 2 to 4 weeks, the resulting increase in blood pressure was lower in Cx37-/- than in wild-type mice, suggesting an alteration in the Ang II response. To investigate this possibility, mice were submitted to a 2-kidney, 1-clip procedure, a renin-dependent model of hypertension. Two weeks after this clipping, Cx37-/- mice were less hypertensive than wild-type mice and, 2 weeks later, their blood pressure had returned to control values, in spite of abnormally high plasma renin levels. In contrast, Cx37-/- and wild-type mice that received N-nitro-l-arginine-methyl-ester, a renin-independent model of hypertension, featured a similar and sustained increase in blood pressure. The data indicate that loss of Cx37 selectively altered the Ang II -dependent pathways. Consistent with this conclusion, aortas of Cx37-/- mice featured an increased basal expression of the Ang II type 2 receptors ( AT 2R), and increased transcripts levels of downstream signaling proteins, such as Cnksr1 and Ptpn6 ( SHP -1). Accordingly, the response of Cx37-/- mice aortas to an ex vivo Ang II exposure was altered, since phosphorylation levels of several proteins of the Ang II pathway ( MLC 2, ERK , and AKT ) remained unchanged. Conclusions These findings provide evidence that Cx37 selectively influences Ang II signaling, mostly via a modulation of the expression of the Ang II type 2 receptor.
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Affiliation(s)
- Loïc Le Gal
- Department of MedicineUniversity of LausanneSwitzerland
| | - Maxime Pellegrin
- Division of AngiologyHeart and Vessel DepartmentCentre Hospitalier Universitaire VaudoisUniversity of LausanneSwitzerland
| | - Tania Santoro
- Department of MedicineUniversity of LausanneSwitzerland
| | - Lucia Mazzolai
- Division of AngiologyHeart and Vessel DepartmentCentre Hospitalier Universitaire VaudoisUniversity of LausanneSwitzerland
| | - Armin Kurtz
- Department of PhysiologyUniversity of RegensburgGermany
| | - Paolo Meda
- Department of Cell Physiology and MetabolismSchool of MedicineCMUUniversity of GenevaSwitzerland
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26
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Enkavi G, Javanainen M, Kulig W, Róg T, Vattulainen I. Multiscale Simulations of Biological Membranes: The Challenge To Understand Biological Phenomena in a Living Substance. Chem Rev 2019; 119:5607-5774. [PMID: 30859819 PMCID: PMC6727218 DOI: 10.1021/acs.chemrev.8b00538] [Citation(s) in RCA: 166] [Impact Index Per Article: 33.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
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Biological
membranes are tricky to investigate. They are complex
in terms of molecular composition and structure, functional
over a wide range of time scales, and characterized
by nonequilibrium conditions. Because of all of these
features, simulations are a great technique to study biomembrane
behavior. A significant part of the functional processes
in biological membranes takes place at the molecular
level; thus computer simulations are the method of
choice to explore how their properties emerge from specific
molecular features and how the interplay among the numerous
molecules gives rise to function over spatial and
time scales larger than the molecular ones. In this
review, we focus on this broad theme. We discuss the current
state-of-the-art of biomembrane simulations that, until
now, have largely focused on a rather narrow picture
of the complexity of the membranes. Given this, we
also discuss the challenges that we should unravel in the
foreseeable future. Numerous features such as the actin-cytoskeleton
network, the glycocalyx network, and nonequilibrium
transport under ATP-driven conditions have so far
received very little attention; however, the potential
of simulations to solve them would be exceptionally high. A
major milestone for this research would be that one day
we could say that computer simulations genuinely research
biological membranes, not just lipid bilayers.
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Affiliation(s)
- Giray Enkavi
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Matti Javanainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Institute of Organic Chemistry and Biochemistry of the Czech Academy of Sciences , Flemingovo naḿesti 542/2 , 16610 Prague , Czech Republic.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Waldemar Kulig
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland
| | - Tomasz Róg
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland
| | - Ilpo Vattulainen
- Department of Physics , University of Helsinki , P.O. Box 64, FI-00014 Helsinki , Finland.,Computational Physics Laboratory , Tampere University , P.O. Box 692, FI-33014 Tampere , Finland.,MEMPHYS-Center for Biomembrane Physics
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27
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Oliveira M, Lira R, Freire T, Luna C, Martins M, Almeida A, Carvalho S, Cortez E, Stumbo AC, Thole A, Carvalho L. Bone marrow mononuclear cell transplantation rescues the glomerular filtration barrier and epithelial cellular junctions in a renovascular hypertension model. Exp Physiol 2019; 104:740-754. [DOI: 10.1113/ep087330] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 02/19/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Mariana Oliveira
- Laboratory of Stem Cell ResearchHistology and Embryology DepartmentBiology InstituteState University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Rafaelle Lira
- Laboratory of Stem Cell ResearchHistology and Embryology DepartmentBiology InstituteState University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Thiago Freire
- Laboratory of Stem Cell ResearchHistology and Embryology DepartmentBiology InstituteState University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Camila Luna
- Laboratory of Stem Cell ResearchHistology and Embryology DepartmentBiology InstituteState University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Marcela Martins
- Laboratory of Stem Cell ResearchHistology and Embryology DepartmentBiology InstituteState University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Aline Almeida
- Laboratory of Stem Cell ResearchHistology and Embryology DepartmentBiology InstituteState University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Simone Carvalho
- Laboratory of Stem Cell ResearchHistology and Embryology DepartmentBiology InstituteState University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Erika Cortez
- Laboratory of Stem Cell ResearchHistology and Embryology DepartmentBiology InstituteState University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Ana Carolina Stumbo
- Laboratory of Stem Cell ResearchHistology and Embryology DepartmentBiology InstituteState University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Alessandra Thole
- Laboratory of Stem Cell ResearchHistology and Embryology DepartmentBiology InstituteState University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
| | - Lais Carvalho
- Laboratory of Stem Cell ResearchHistology and Embryology DepartmentBiology InstituteState University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
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28
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Kubincová P, Sychrová E, Raška J, Basu A, Yawer A, Dydowiczová A, Babica P, Sovadinová I. Polycyclic Aromatic Hydrocarbons and Endocrine Disruption: Role of Testicular Gap Junctional Intercellular Communication and Connexins. Toxicol Sci 2019; 169:70-83. [DOI: 10.1093/toxsci/kfz023] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Abstract
Ambient air pollution and smoking are well-documented risk factors for male infertility. Prevalent air pollutants and cigarette smoke components, polycyclic aromatic hydrocarbons (PAHs), are environmental and occupational toxicants that act as chemicals disrupting endocrine regulation and reproductive potential in males. Testicular gap junctional intercellular communication (GJIC) is critical for normal development and function of testicular tissue, thus we assessed GJIC as a process potentially targeted by PAHs in testes. Lower MW PAHs with a bay or bay-like region rapidly dysregulated GJIC in Leydig TM3 cells by relocalization of major testicular gap junctional protein connexin 43 (Cx43) from plasma membrane to cytoplasm. This was associated with colocalization between Cx43 and ubiquitin in intracellular compartments, but without any effect on Cx43 degradation rate or steady-state Cx43 mRNA levels. A longer exposure to active PAHs decreased steady-state levels of full-length Cx43 protein and its 2 N-truncated isoforms. Inhibition of GJIC by PAHs, similarly to a prototypic GJIC-inhibitor TPA, was mediated via the MAP kinase-Erk1/2 and PKC pathways. Polycyclic aromatic hydrocarbon-induced GJIC dysregulation in testes was cell-type-specific because neither PAH dysregulated GJIC in Sertoli TM4 cells, despite PAHs were rapidly taken up by both Leydig TM3 as well as Sertoli TM4 cells. Because TPA effectively dysregulated GJIC in both testicular cell types, a unique regulator of GJIC targeted by PAHs might exist in Leydig TM3 cells. Our results indicate that PAHs could be a potential etiological agent contributing to reproductive dysfunctions in males through an impairment of testicular GJIC and junctional and/or nonjunctional functions of Cx43.
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Affiliation(s)
- Petra Kubincová
- Masaryk University, Faculty of Science, RECETOX, Brno, Czech Republic
| | - Eliška Sychrová
- Masaryk University, Faculty of Science, RECETOX, Brno, Czech Republic
| | - Jan Raška
- Masaryk University, Faculty of Science, RECETOX, Brno, Czech Republic
| | - Amrita Basu
- Masaryk University, Faculty of Science, RECETOX, Brno, Czech Republic
| | - Affiefa Yawer
- Masaryk University, Faculty of Science, RECETOX, Brno, Czech Republic
| | - Aneta Dydowiczová
- Masaryk University, Faculty of Science, RECETOX, Brno, Czech Republic
| | - Pavel Babica
- Masaryk University, Faculty of Science, RECETOX, Brno, Czech Republic
| | - Iva Sovadinová
- Masaryk University, Faculty of Science, RECETOX, Brno, Czech Republic
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29
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Hassan GS, Jacques D, D'Orléans-Juste P, Magder S, Bkaily G. Physical contact between human vascular endothelial and smooth muscle cells modulates cytosolic and nuclear calcium homeostasis. Can J Physiol Pharmacol 2018; 96:655-661. [PMID: 29756482 DOI: 10.1139/cjpp-2018-0093] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The interaction between vascular endothelial cells (VECs) and vascular smooth muscle cells (VSMCs) plays an important role in the modulation of vascular tone. There is, however, no information on whether direct physical communication regulates the intracellular calcium levels of human VECs (hVECs) and (or) human VSMCs (hVSMCs). Thus, the objective of the study is to verify whether co-culture of hVECs and hVSMCs modulates cytosolic ([Ca2+]c) and nuclear calcium ([Ca2+]n) levels via physical contact and (or) factors released by both cell types. Quantitative 3D confocal microscopy for [Ca2+]c and [Ca2+]n measurement was performed in cultured hVECs or hVSMCs or in co-culture of hVECs-hVSMCs. Our results show that: (1) physical contact between hVECs-hVECs or hVSMCs-hVSMCs does not affect [Ca2+]c and [Ca2+]n in these 2 cell types; (2) physical contact between hVECs and hVSMCs induces a significant increase only of [Ca2+]n of hVECs without affecting the level of [Ca2+]c and [Ca2+]n of hVSMCs; and (3) preconditioned culture medium of hVECs or hVSMCs does not affect [Ca2+]c and [Ca2+]n of both types of cells. We concluded that physical contact between hVECs and hVSMCs only modulates [Ca2+]n in hVECs. The increase of [Ca2+]n in hVECs may modulate nuclear functions that are calcium dependent.
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Affiliation(s)
- Ghada S Hassan
- a Department of Anatomy and Cell Biology, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Danielle Jacques
- a Department of Anatomy and Cell Biology, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Pedro D'Orléans-Juste
- b Department of Pharmacology and Physiology, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
| | - Sheldon Magder
- c McGill University Health Centre, Montreal, QC H3A 1A1, Canada
| | - Ghassan Bkaily
- a Department of Anatomy and Cell Biology, Faculty of Medicine, Université de Sherbrooke, Sherbrooke, QC J1H 5N4, Canada
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Ray A, Katoch P, Jain N, Mehta PP. Dileucine-like motifs in the C-terminal tail of connexin32 control its endocytosis and assembly into gap junctions. J Cell Sci 2018; 131:jcs207340. [PMID: 29361528 PMCID: PMC5897717 DOI: 10.1242/jcs.207340] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 01/11/2018] [Indexed: 12/11/2022] Open
Abstract
Defects in assembly of gap junction-forming proteins, called connexins (Cxs), are observed in a variety of cancers. Connexin32 (Cx32; also known as GJB1) is expressed by the polarized cells in epithelia. We discovered two dileucine-based motifs, which govern the intracellular sorting and endocytosis of transmembrane proteins, in the C-terminal tail of Cx32 and explored their role in regulating its endocytosis and gap junction-forming abilities in pancreatic and prostate cancer cells. One motif, designated as LI, was located near the juxtamembrane domain, whereas the other, designated as LL, was located distally. We also discovered a non-canonical motif, designated as LR, in the C-terminal tail. Our results showed that rendering these motifs non-functional had no effect on the intracellular sorting of Cx32. However, rendering the LL or LR motif nonfunctional enhanced the formation of gap junctions by inhibiting Cx32 endocytosis by the clathrin-mediated pathway. Rendering the LI motif nonfunctional inhibited gap junction formation by augmenting the endocytosis of Cx32 via the LL and LR motifs. Our studies have defined distinct roles of these motifs in regulating the endocytosis of Cx32 and its gap junction-forming ability.This article has an associated First Person interview with the first author of the paper.
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Affiliation(s)
- Anuttoma Ray
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Parul Katoch
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
| | - Nimansha Jain
- Department of Neurology, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Parmender P Mehta
- Department of Biochemistry and Molecular Biology, University of Nebraska Medical Center, Omaha, NE 68198, USA
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Gap junction communication between chromaffin cells: the hidden face of adrenal stimulus-secretion coupling. Pflugers Arch 2017; 470:89-96. [PMID: 28735418 DOI: 10.1007/s00424-017-2032-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2017] [Revised: 07/07/2017] [Accepted: 07/10/2017] [Indexed: 10/19/2022]
Abstract
From birth to death, catecholamine secretion undergoes continuous adjustments, allowing the organism to adapt to homeostasis changes. To cope with these stressful conditions, the neuroendocrine cells of the adrenal medulla play an immediate and crucial role. Chromaffin cell-driven catecholamine release is chiefly controlled by a neurogenic command that arises from the sympathetic nervous system, which releases acetylcholine at the splanchnic nerve terminal-chromaffin cell synapses. In addition to receiving several synaptic inputs individually, chromaffin cells are coupled by gap junctions. This raises interesting questions about the usefulness and the role of the gap junctional coupling within the chromaffin tissue, considering that secretory function is efficiently completed by the neurogenic pathway. The findings that gap junctions contribute to catecholamine secretion, both ex vivo and in vivo, provide some early answers, but their involvement in other cellular functions still remains unexplored. This review summarizes the molecular and physiological evidence that gap junctions can act either as an accelerator or a brake of stimulus-secretion coupling and discusses this functional plasticity in the context of specific needs in circulating catecholamine levels. It introduces the concept of gap junctions as sympathetic activity sensors and guardians of the functional integrity of the chromaffin tissue.
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