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Luo Y, Zheng S, Xiao W, Zhang H, Li Y. Pannexins in the musculoskeletal system: new targets for development and disease progression. Bone Res 2024; 12:26. [PMID: 38705887 PMCID: PMC11070431 DOI: 10.1038/s41413-024-00334-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 03/04/2024] [Accepted: 04/01/2024] [Indexed: 05/07/2024] Open
Abstract
During cell differentiation, growth, and development, cells can respond to extracellular stimuli through communication channels. Pannexin (Panx) family and connexin (Cx) family are two important types of channel-forming proteins. Panx family contains three members (Panx1-3) and is expressed widely in bone, cartilage and muscle. Although there is no sequence homology between Panx family and Cx family, they exhibit similar configurations and functions. Similar to Cxs, the key roles of Panxs in the maintenance of physiological functions of the musculoskeletal system and disease progression were gradually revealed later. Here, we seek to elucidate the structure of Panxs and their roles in regulating processes such as osteogenesis, chondrogenesis, and muscle growth. We also focus on the comparison between Cx and Panx. As a new key target, Panxs expression imbalance and dysfunction in muscle and the therapeutic potentials of Panxs in joint diseases are also discussed.
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Affiliation(s)
- Yan Luo
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- Department of Clinical Medicine, Xiangya Medicine School, Central South University, Changsha, Hunan, 410008, China
| | - Shengyuan Zheng
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- Department of Clinical Medicine, Xiangya Medicine School, Central South University, Changsha, Hunan, 410008, China
| | - Wenfeng Xiao
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China
| | - Hang Zhang
- Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, 518055, China.
| | - Yusheng Li
- Department of Orthopedics, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China.
- National Clinical Research Center for Geriatric Disorders, Xiangya Hospital, Central South University, Changsha, Hunan, 410008, China.
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2
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Rengarajan A, Goldblatt HE, Beebe DJ, Virumbrales-Muñoz M, Boeldt DS. Immune cells and inflammatory mediators cause endothelial dysfunction in a vascular microphysiological system. LAB ON A CHIP 2024; 24:1808-1820. [PMID: 38363157 PMCID: PMC11022267 DOI: 10.1039/d3lc00824j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2024]
Abstract
Functional assessment of endothelium serves as an important indicator of vascular health and is compromised in vascular disorders including hypertension, atherosclerosis, and preeclampsia. Endothelial dysfunction in these cases is linked to dysregulation of the immune system involving both changes to immune cells and increased secretion of inflammatory cytokines. Herein, we utilize a well-established microfluidic device to generate a 3-dimensional vascular microphysiological system (MPS) consisting of a tubular blood vessel lined with human umbilical vein endothelial cells (HUVECs) to evaluate endothelial function measured via endothelial permeability and Ca2+ signaling. We evaluated the effect of a mixture of factors associated with inflammation and cardiovascular disease (TNFα, VEGF-A, IL-6 at 10 ng ml-1 each) on vascular MPS and inferred that inflammatory mediators contribute to endothelial dysfunction by disrupting the endothelial barrier over a 48 hour treatment and by diminishing coordinated Ca2+ activity over a 1 hour treatment. We also evaluated the effect of peripheral blood mononuclear cells (PBMCs) on endothelial permeability and Ca2+ signaling in the HUVEC MPS. HUVECs were co-cultured with PBMCs either directly wherein PBMCs passed through the lumen or indirectly with PBMCs embedded in the supporting collagen hydrogel. We revealed that phytohemagglutinin (PHA)-M activated PBMCs cause endothelial dysfunction in MPS both through increased permeability and decreased coordinated Ca2+ activity compared to non-activated PBMCs. Our MPS has potential applications in modeling cardiovascular disorders and screening for potential treatments using measures of endothelial function.
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Affiliation(s)
- Aishwarya Rengarajan
- Department of Obstetrics & Gynecology, University of Wisconsin-Madison, School of Medicine and Public Health, USA.
- Perinatal Research Laboratories, UnityPoint Health-Meriter Hospital, 202 South Park St. 7E, Madison, WI, 53715, USA
| | - Hannah E Goldblatt
- Department of Obstetrics & Gynecology, University of Wisconsin-Madison, School of Medicine and Public Health, USA.
- Perinatal Research Laboratories, UnityPoint Health-Meriter Hospital, 202 South Park St. 7E, Madison, WI, 53715, USA
| | - David J Beebe
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI, 53705, USA
- University of Wisconsin Carbone Cancer Center, Wisconsin Institutes for Medical Research, 1111 Highland Ave, Madison, WI, 53705, USA
- Department of Biomedical Engineering, Wisconsin Institutes for Medical Research, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI, 53705, USA
| | - María Virumbrales-Muñoz
- Department of Obstetrics & Gynecology, University of Wisconsin-Madison, School of Medicine and Public Health, USA.
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, 1111 Highland Avenue, Madison, WI, 53705, USA
- University of Wisconsin Carbone Cancer Center, Wisconsin Institutes for Medical Research, 1111 Highland Ave, Madison, WI, 53705, USA
| | - Derek S Boeldt
- Department of Obstetrics & Gynecology, University of Wisconsin-Madison, School of Medicine and Public Health, USA.
- Perinatal Research Laboratories, UnityPoint Health-Meriter Hospital, 202 South Park St. 7E, Madison, WI, 53715, USA
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3
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Geng Z, Guan S, Wang S, Yu Z, Liu T, Du S, Zhu C. Intercellular mitochondrial transfer in the brain, a new perspective for targeted treatment of central nervous system diseases. CNS Neurosci Ther 2023; 29:3121-3135. [PMID: 37424172 PMCID: PMC10580346 DOI: 10.1111/cns.14344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 05/08/2023] [Accepted: 06/24/2023] [Indexed: 07/11/2023] Open
Abstract
AIM Mitochondria is one of the important organelles involved in cell energy metabolism and regulation and also play a key regulatory role in abnormal cell processes such as cell stress, cell damage, and cell canceration. Recent studies have shown that mitochondria can be transferred between cells in different ways and participate in the occurrence and development of many central nervous system diseases. We aim to review the mechanism of mitochondrial transfer in the progress of central nervous system diseases and the possibility of targeted therapy. METHODS The PubMed databank, the China National Knowledge Infrastructure databank, and Wanfang Data were searched to identify the experiments of intracellular mitochondrial transferrin central nervous system. The focus is on the donors, receptors, transfer pathways, and targeted drugs of mitochondrial transfer. RESULTS In the central nervous system, neurons, glial cells, immune cells, and tumor cells can transfer mitochondria to each other. Meanwhile, there are many types of mitochondrial transfer, including tunneling nanotubes, extracellular vesicles, receptor cell endocytosis, gap junction channels, and intercellular contact. A variety of stress signals, such as the release of damaged mitochondria, mitochondrial DNA, or other mitochondrial products and the elevation of reactive oxygen species, can trigger the transfer of mitochondria from donor cells to recipient cells. Concurrently, a variety of molecular pathways and related inhibitors can affect mitochondrial intercellular transfer. CONCLUSION This study reviews the phenomenon of intercellular mitochondrial transfer in the central nervous system and summarizes the corresponding transfer pathways. Finally, we propose targeted pathways and treatment methods that may be used to regulate mitochondrial transfer for the treatment of related diseases.
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Affiliation(s)
- Ziang Geng
- Department of NeurosurgeryShengjing Hospital of China Medical UniversityShenyangChina
| | - Shu Guan
- Department of Surgical Oncology and Breast SurgeryThe First Hospital of China Medical UniversityShenyangChina
| | - Siqi Wang
- Department of Radiation OncologyThe First Hospital of China Medical UniversityShenyangChina
| | - Zhongxue Yu
- Department of Cardiovascular UltrasoundThe First Hospital of China Medical UniversityShenyangChina
| | - Tiancong Liu
- Department of OtolaryngologyShengjing Hospital of China Medical UniversityShenyangChina
| | - Shaonan Du
- Department of NeurosurgeryShengjing Hospital of China Medical UniversityShenyangChina
| | - Chen Zhu
- Department of NeurosurgeryThe First Hospital of China Medical UniversityShenyangChina
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LRP6-mediated phosphorylation of connexin43 in myocardial infarction. iScience 2023; 26:106160. [PMID: 36879803 PMCID: PMC9985046 DOI: 10.1016/j.isci.2023.106160] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 10/30/2022] [Accepted: 02/02/2023] [Indexed: 02/11/2023] Open
Abstract
Ventricular tachycardia (VT) and ventricular fibrillation are most causes of early death in patients with acute myocardial infarction (AMI). Conditional cardiac-specific low-density lipoprotein receptor-related protein 6 (LRP6)-knockout mice with connexin 43 (Cx43) reduction triggered the lethal ventricular arrhythmias. Thus, it is necessary for exploring whether LRP6 and its upstream genes circRNA1615 mediate the phosphorylation of Cx43 in VT of AMI. Here, we showed that circRNA1615 regulated the expression of LRP6 mRNA through sponge adsorption of miR-152-3p. Importantly, LRP6 interference fragments aggravated hypoxia injury of Cx43, while overexpression of LRP6 improved the phosphorylation of Cx43. Subsequently, interference with G-protein alpha subunit (Gαs) downstream of LRP6 further inhibited the phosphorylation of Cx43, along with increasing VT. Our results demonstrated that LRP6 upstream genes circRNA1615 controlled the damage effect and VT in AMI, and LRP6 mediated the phosphorylation of Cx43 via Gαs which played a role in VT of AMI.
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Hutchings DC, Madders GWP, Niort BC, Bode EF, Waddell CA, Woods LS, Dibb KM, Eisner DA, Trafford AW. Interaction of background Ca 2+ influx, sarcoplasmic reticulum threshold and heart failure in determining propensity for Ca 2+ waves in sheep heart. J Physiol 2022; 600:2637-2650. [PMID: 35233776 PMCID: PMC9310721 DOI: 10.1113/jp282168] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 02/25/2022] [Indexed: 11/11/2022] Open
Abstract
Ventricular arrhythmias can cause death in heart failure (HF). A trigger is the occurrence of Ca2+ waves which activate a Na+ -Ca2+ exchange (NCX) current, leading to delayed after-depolarisations and triggered action potentials. Waves arise when sarcoplasmic reticulum (SR) Ca2+ content reaches a threshold and are commonly induced experimentally by raising external Ca2+ , although the mechanism by which this causes waves is unclear and was the focus of this study. Intracellular Ca2+ was measured in voltage-clamped ventricular myocytes from both control sheep and those subjected to rapid pacing to produce HF. Threshold SR Ca2+ content was determined by applying caffeine (10 mM) following a wave and integrating wave and caffeine-induced NCX currents. Raising external Ca2+ induced waves in a greater proportion of HF cells than control. The associated increase of SR Ca2+ content was smaller in HF due to a lower threshold. Raising external Ca2+ had no effect on total influx via the L-type Ca2+ current, ICa-L , and increased efflux on NCX. Analysis of sarcolemmal fluxes revealed substantial background Ca2+ entry which sustains Ca2+ efflux during waves in the steady state. Wave frequency and background Ca2+ entry were decreased by Gd3+ or the TRPC6 inhibitor BI 749327. These agents also blocked Mn2+ entry. Inhibiting connexin hemi-channels, TRPC1/4/5, L-type channels or NCX had no effect on background entry. In conclusion, raising external Ca2+ induces waves via a background Ca2+ influx through TRPC6 channels. The greater propensity to waves in HF results from increased background entry and decreased threshold SR content. KEY POINTS: Heart failure is a pro-arrhythmic state and arrhythmias are a major cause of death. At the cellular level, Ca2+ waves resulting in delayed after-depolarisations are a key trigger of arrhythmias. Ca2+ waves arise when the sarcoplasmic reticulum (SR) becomes overloaded with Ca2+ . We investigate the mechanism by which raising external Ca2+ causes waves, and how this is modified in heart failure. We demonstrate that a novel sarcolemmal background Ca2+ influx via the TRPC6 channel is responsible for SR Ca2+ overload and Ca2+ waves. The increased propensity for Ca2+ waves in heart failure results from an increase of background influx, and a lower threshold SR content. The results of the present study highlight a novel mechanism by which Ca2+ waves may arise in heart failure, providing a basis for future work and novel therapeutic targets.
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Affiliation(s)
- David C Hutchings
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK.,Manchester University NHS Foundation Trust, Manchester, UK
| | - George W P Madders
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Barbara C Niort
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Elizabeth F Bode
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Caitlin A Waddell
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Lori S Woods
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Katharine M Dibb
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - David A Eisner
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
| | - Andrew W Trafford
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, Manchester Academic Health Science Centre, University of Manchester, Manchester, UK
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Casanellas I, Lagunas A, Vida Y, Pérez-Inestrosa E, Rodríguez-Pereira C, Magalhaes J, Andrades JA, Becerra J, Samitier J. Nanoscale ligand density modulates gap junction intercellular communication of cell condensates during chondrogenesis. Nanomedicine (Lond) 2022; 17:775-791. [PMID: 35642556 DOI: 10.2217/nnm-2021-0399] [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: 11/21/2022] Open
Abstract
Aim: To unveil the influence of cell-matrix adhesions in the establishment of gap junction intercellular communication (GJIC) during cell condensation in chondrogenesis. Materials & methods: Previously developed nanopatterns of the cell adhesive ligand arginine-glycine-aspartic acid were used as cell culture substrates to control cell adhesion at the nanoscale. In vitro chondrogenesis of mesenchymal stem cells was conducted on the nanopatterns. Cohesion and GJIC were evaluated in cell condensates. Results: Mechanical stability and GJIC are enhanced by a nanopattern configuration in which 90% of the surface area presents adhesion sites separated less than 70 nm, thus providing an onset for cell signaling. Conclusion: Cell-matrix adhesions regulate GJIC of mesenchymal cell condensates during in vitro chondrogenesis from a threshold configuration at the nanoscale.
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Affiliation(s)
- Ignasi Casanellas
- Institute for Bioengineering of Catalonia (IBEC), Barcelona Institute of Science &Technology (BIST). c/Baldiri Reixac, 10-12, Barcelona, 08028, Spain.,Department of Electronics & Biomedical Engineering, University of Barcelona (UB). c/Martí i Franquès, 1, 08028, Barcelona, Spain.,Biomedical Research Networking Center in Bioengineering,Biomaterials & Nanomedicine (CIBER-BBN). Av. Monforte de Lemos, 3-5. Pabellón 11. Planta 0, Madrid, 28029, Spain
| | - Anna Lagunas
- Institute for Bioengineering of Catalonia (IBEC), Barcelona Institute of Science &Technology (BIST). c/Baldiri Reixac, 10-12, Barcelona, 08028, Spain.,Biomedical Research Networking Center in Bioengineering,Biomaterials & Nanomedicine (CIBER-BBN). Av. Monforte de Lemos, 3-5. Pabellón 11. Planta 0, Madrid, 28029, Spain
| | - Yolanda Vida
- Universidad de Málaga-IBIMA, Dpto. Química Orgánica. Campus de Teatinos s/n, Málaga, 29071, Spain.,Centro Andaluz de Nanomedicina y Biotecnología-BIONAND. Parque Tecnológico de Andalucía, c/Severo Ochoa 35, C,ampanillas, Málaga, 29590, Spain
| | - Ezequiel Pérez-Inestrosa
- Universidad de Málaga-IBIMA, Dpto. Química Orgánica. Campus de Teatinos s/n, Málaga, 29071, Spain.,Centro Andaluz de Nanomedicina y Biotecnología-BIONAND. Parque Tecnológico de Andalucía, c/Severo Ochoa 35, C,ampanillas, Málaga, 29590, Spain
| | - Cristina Rodríguez-Pereira
- Unidad de Medicina Regenerativa, Grupo de Investigación en Reumatología (GIR), Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas, Universidade da Coruña (UDC). c/Xubias de Arriba, 84, A Coruña, 15006, Spain
| | - Joana Magalhaes
- Biomedical Research Networking Center in Bioengineering,Biomaterials & Nanomedicine (CIBER-BBN). Av. Monforte de Lemos, 3-5. Pabellón 11. Planta 0, Madrid, 28029, Spain.,Unidad de Medicina Regenerativa, Grupo de Investigación en Reumatología (GIR), Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña (CHUAC), Sergas, Universidade da Coruña (UDC). c/Xubias de Arriba, 84, A Coruña, 15006, Spain
| | - José A Andrades
- Biomedical Research Networking Center in Bioengineering,Biomaterials & Nanomedicine (CIBER-BBN). Av. Monforte de Lemos, 3-5. Pabellón 11. Planta 0, Madrid, 28029, Spain.,Centro Andaluz de Nanomedicina y Biotecnología-BIONAND. Parque Tecnológico de Andalucía, c/Severo Ochoa 35, C,ampanillas, Málaga, 29590, Spain.,Department of Cell Biology, Genetics & Physiology, Universidad de Málaga (UMA), Instituto de Investigación Biomédica de Málaga (IBIMA). Av. Cervantes, 2, Málaga, 29071, Spain
| | - José Becerra
- Biomedical Research Networking Center in Bioengineering,Biomaterials & Nanomedicine (CIBER-BBN). Av. Monforte de Lemos, 3-5. Pabellón 11. Planta 0, Madrid, 28029, Spain.,Centro Andaluz de Nanomedicina y Biotecnología-BIONAND. Parque Tecnológico de Andalucía, c/Severo Ochoa 35, C,ampanillas, Málaga, 29590, Spain.,Department of Cell Biology, Genetics & Physiology, Universidad de Málaga (UMA), Instituto de Investigación Biomédica de Málaga (IBIMA). Av. Cervantes, 2, Málaga, 29071, Spain
| | - Josep Samitier
- Institute for Bioengineering of Catalonia (IBEC), Barcelona Institute of Science &Technology (BIST). c/Baldiri Reixac, 10-12, Barcelona, 08028, Spain.,Department of Electronics & Biomedical Engineering, University of Barcelona (UB). c/Martí i Franquès, 1, 08028, Barcelona, Spain.,Biomedical Research Networking Center in Bioengineering,Biomaterials & Nanomedicine (CIBER-BBN). Av. Monforte de Lemos, 3-5. Pabellón 11. Planta 0, Madrid, 28029, Spain
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Zhi Z, Xiang J, Fu Q, Pei X, Zhou D, Cao Y, Xie L, Zhang S, Chen S, Qu J, Zhou X. The Role of Retinal Connexins Cx36 and Horizontal Cell Coupling in Emmetropization in Guinea Pigs. Invest Ophthalmol Vis Sci 2021; 62:27. [PMID: 34283211 PMCID: PMC8300059 DOI: 10.1167/iovs.62.9.27] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 06/24/2021] [Indexed: 11/24/2022] Open
Abstract
Purpose The purpose of this study was to determine whether retinal gap junctions (GJs) via connexin 36 (Cx36, mediating coupling of many retinal cell types) and horizontal cell (HC-HC) coupling, are involved in emmetropization. Methods Guinea pigs (3 weeks old) were monocularly form deprived (FD) or raised without FD (in normal visual [NV] environment) for 2 days or 4 weeks; alternatively, they wore a -4 D lens (hyperopic defocus [HD]) or 0 D lens for 2 days or 1 week. FD and NV eyes received daily subconjunctival injections of a nonspecific GJ-uncoupling agent, 18-β-Glycyrrhetinic Acid (18-β-GA). The amounts of total Cx36 and of phosphorylated Cx36 (P-Cx36; activated state that increases cell-cell coupling), in the inner and outer plexiform layers (IPLs and OPLs), were evaluated by quantitative immunofluorescence (IF), and HC-HC coupling was evaluated by cut-loading with neurobiotin. Results FD per se (excluding effect of light-attenuation) increased HC-HC coupling in OPL, whereas HD did not affect it. HD for 2 days or 1 week had no significant effect on retinal content of Cx36 or P-Cx36. FD for 4 weeks decreased the total amounts of Cx36 and P-Cx36, and the P-Cx36/Cx36 ratio, in the IPL. Subconjunctival 18-β-GA induced myopia in NV eyes and increased the myopic shifts in FD eyes, while reducing the amounts of Cx36 and P-Cx36 in both the IPL and OPL. Conclusions These results suggest that cell-cell coupling via GJs containing Cx36 (particularly those in the IPL) plays a role in emmetropization and form deprivation myopia (FDM) in mammals. Although both FD and 18-β-GA induced myopia, they had opposite effects on HC-HC coupling. These findings suggest that HC-HC coupling in the OPL might not play a significant role in emmetropization and myopia development.
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Affiliation(s)
- Zhina Zhi
- School of Optometry and Ophthalmology, and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health People's Republic of China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Jing Xiang
- School of Optometry and Ophthalmology, and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health People's Republic of China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Qian Fu
- School of Optometry and Ophthalmology, and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health People's Republic of China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Xiaomeng Pei
- School of Optometry and Ophthalmology, and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health People's Republic of China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Dengke Zhou
- School of Optometry and Ophthalmology, and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health People's Republic of China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Yuqing Cao
- School of Optometry and Ophthalmology, and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health People's Republic of China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Liqin Xie
- School of Optometry and Ophthalmology, and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health People's Republic of China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Sen Zhang
- School of Optometry and Ophthalmology, and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health People's Republic of China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Si Chen
- School of Optometry and Ophthalmology, and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health People's Republic of China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Jia Qu
- School of Optometry and Ophthalmology, and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health People's Republic of China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
| | - Xiangtian Zhou
- School of Optometry and Ophthalmology, and Eye Hospital, Wenzhou Medical University, Wenzhou, Zhejiang, China
- State Key Laboratory and Key Laboratory of Vision Science, Ministry of Health People's Republic of China and Zhejiang Provincial Key Laboratory of Ophthalmology and Optometry, Wenzhou, Zhejiang, China
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8
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Hudson L, Begg M, Wright B, Cheek T, Jahoda CAB, Reynolds NJ. Dominant effect of gap junction communication in wound-induced calcium-wave, NFAT activation and wound closure in keratinocytes. J Cell Physiol 2021; 236:8171-8183. [PMID: 34180060 DOI: 10.1002/jcp.30488] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 05/18/2021] [Accepted: 06/15/2021] [Indexed: 12/13/2022]
Abstract
Wounding induces a calcium wave and disrupts the calcium gradient across the epidermis but mechanisms mediating calcium and downstream signalling, and longer-term wound healing responses are incompletely understood. As expected, live-cell confocal imaging of Fluo-4-loaded normal human keratinocytes showed an immediate increase in [Ca2+ ]i at the wound edge that spread as a calcium wave (8.3 µm/s) away from the wound edge with gradually diminishing rate of rise and amplitude. The amplitude and area under the curve of [Ca2+ ]i flux was increased in high (1.2 mM) [Ca2+ ]o media. 18α-glycyrrhetinic acid (18αGA), a gap-junction inhibitor or hexokinase, an ATP scavenger, blocked the wound-induced calcium wave, dependent in part on [Ca2+ ]o . Wounding in a high [Ca2+ ]o increased nuclear factor of activated T-cells (NFAT) but not NFkB activation, assessed by dual-luciferase receptor assays compared to unwounded cells. Treatment with 18αGA or the store-operated channel blocker GSK-7975A inhibited wound-induced NFAT activation, whereas treatment with hexokinase did not. Real-time cell migration analysis, measuring wound closure rates over 24 h, revealed that 18αGA essentially blocked wound closure whereas hexokinase and GSK-7975A showed relatively minimal effects. Together these data indicate that while both gap-junction communication and ATP release from damaged cells are important in regulating the wound-induced calcium wave, long-term transcriptional and functional responses are dominantly regulated by gap-junction communication.
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Affiliation(s)
- Laura Hudson
- Institute of Translational and Clinical Medicine, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Malcolm Begg
- Medicines Research Centre, GlaxoSmithKline, London, UK
| | - Blythe Wright
- Institute of Translational and Clinical Medicine, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | - Tim Cheek
- Biosciences Institute, Medical School, Newcastle University, Newcastle upon Tyne, UK
| | | | - Nick J Reynolds
- Institute of Translational and Clinical Medicine, Medical School, Newcastle University, Newcastle upon Tyne, UK.,Department of Dermatology, Royal Victoria Infirmary and NIHR Newcastle Biomedical Research Centre, Newcastle Hospitals NHS Foundation Trust, Newcastle upon Tyne, UK
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Buckley C, Zhang X, Wilson C, McCarron JG. Carbenoxolone and 18β-glycyrrhetinic acid inhibit inositol 1,4,5-trisphosphate-mediated endothelial cell calcium signalling and depolarise mitochondria. Br J Pharmacol 2021; 178:896-912. [PMID: 33269468 PMCID: PMC9328419 DOI: 10.1111/bph.15329] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 09/08/2020] [Accepted: 09/19/2020] [Indexed: 12/30/2022] Open
Abstract
BACKGROUND AND PURPOSE Coordinated endothelial control of cardiovascular function is proposed to occur by endothelial cell communication via gap junctions and connexins. To study intercellular communication, the pharmacological agents carbenoxolone (CBX) and 18β-glycyrrhetinic acid (18βGA) are used widely as connexin inhibitors and gap junction blockers. EXPERIMENTAL APPROACH We investigated the effects of CBX and 18βGA on intercellular Ca2+ waves, evoked by inositol 1,4,5-trisphosphate (IP3 ) in the endothelium of intact mesenteric resistance arteries. KEY RESULTS Acetycholine-evoked IP3 -mediated Ca2+ release and propagated waves were inhibited by CBX (100 μM) and 18βGA (40 μM). Unexpectedly, the Ca2+ signals were inhibited uniformly in all cells, suggesting that CBX and 18βGA reduced Ca2+ release. Localised photolysis of caged IP3 (cIP3 ) was used to provide precise spatiotemporal control of site of cell activation. Local cIP3 photolysis generated reproducible Ca2+ increases and Ca2+ waves that propagated across cells distant to the photolysis site. CBX and 18βGA each blocked Ca2+ waves in a time-dependent manner by inhibiting the initiating IP3 -evoked Ca2+ release event rather than block of gap junctions. This effect was reversed on drug washout and was unaffected by small or intermediate K+ -channel blockers. Furthermore, CBX and 18βGA each rapidly and reversibly collapsed the mitochondrial membrane potential. CONCLUSION AND IMPLICATIONS CBX and 18βGA inhibit IP3 -mediated Ca2+ release and depolarise the mitochondrial membrane potential. These results suggest that CBX and 18βGA may block cell-cell communication by acting at sites that are unrelated to gap junctions.
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Affiliation(s)
- Charlotte Buckley
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Xun Zhang
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - Calum Wilson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
| | - John G McCarron
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, Glasgow, UK
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Stasiak SE, Jamieson RR, Bouffard J, Cram EJ, Parameswaran H. Intercellular communication controls agonist-induced calcium oscillations independently of gap junctions in smooth muscle cells. SCIENCE ADVANCES 2020; 6:eaba1149. [PMID: 32821820 PMCID: PMC7406377 DOI: 10.1126/sciadv.aba1149] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Accepted: 06/18/2020] [Indexed: 06/11/2023]
Abstract
In this study, we report the existence of a communication system among human smooth muscle cells that uses mechanical forces to frequency modulate long-range calcium waves. An important consequence of this mechanical signaling is that changes in stiffness of the underlying extracellular matrix can interfere with the frequency modulation of Ca2+ waves, causing smooth muscle cells from healthy human donors to falsely perceive a much higher agonist dose than they actually received. This aberrant sensing of contractile agonist dose on stiffer matrices is completely absent in isolated smooth muscle cells, although the isolated cells can sense matrix rigidity. We show that the intercellular communication that enables this collective Ca2+ response in smooth muscle cells does not involve transport across gap junctions or extracellular diffusion of signaling molecules. Instead, our data support a collective model in which mechanical signaling among smooth muscle cells regulates their response to contractile agonists.
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Affiliation(s)
- S. E. Stasiak
- Department of Bioengineering, Northeastern University, Boston, MA 02115, USA
| | - R. R. Jamieson
- Department of Bioengineering, Northeastern University, Boston, MA 02115, USA
| | - J. Bouffard
- Department of Bioengineering, Northeastern University, Boston, MA 02115, USA
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - E. J. Cram
- Department of Bioengineering, Northeastern University, Boston, MA 02115, USA
- Department of Biology, Northeastern University, Boston, MA 02115, USA
| | - H. Parameswaran
- Department of Bioengineering, Northeastern University, Boston, MA 02115, USA
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Yawer A, Sychrová E, Labohá P, Raška J, Jambor T, Babica P, Sovadinová I. Endocrine-disrupting chemicals rapidly affect intercellular signaling in Leydig cells. Toxicol Appl Pharmacol 2020; 404:115177. [PMID: 32739526 DOI: 10.1016/j.taap.2020.115177] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Revised: 07/19/2020] [Accepted: 07/28/2020] [Indexed: 01/25/2023]
Abstract
A decline in male fertility possibly caused by environmental contaminants, namely endocrine-disrupting chemicals (EDCs), is a topic of public concern and scientific interest. This study addresses a specific role of testicular gap junctional intercellular communication (GJIC) between adjacent prepubertal Leydig cells in endocrine disruption and male reproductive toxicity. Organochlorine pesticides (lindane, methoxychlor, DDT), industrial chemicals (PCB153, bisphenol A, nonylphenol and octylphenol) as well as personal care product components (triclosan, triclocarban) rapidly dysregulated GJIC in murine Leydig TM3 cells. The selected GJIC-inhibiting EDCs (methoxychlor, triclosan, triclocarban, lindane, DDT) caused the immediate GJIC disruption by the relocation of gap junctional protein connexin 43 (Cx43) from the plasma membrane and the alternation of Cx43 phosphorylation pattern (Ser368, Ser279, Ser282) of its full-length and two N-truncated isoforms. After more prolonged exposure (24 h), EDCs decreased steady-state levels of full-length Cx43 protein and its two N-truncated isoforms, and eventually (triclosan, triclocarban) also tight junction protein Tjp-1. The disturbance of GJIC was accompanied by altered activity of mitogen-activated protein kinases MAPK-Erk1/2 and MAPK-p38, and a decrease in stimulated progesterone production. Our results indicate that EDCs might disrupt testicular homeostasis and development via disruption of testicular GJIC, a dysregulation of junctional and non-junctional functions of Cx43, activation of MAPKs, and disruption of an early stage of steroidogenesis in prepubertal Leydig cells. These critical disturbances of Leydig cell development and functions during a prepubertal period might be contributing to impaired male reproduction health later on.
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Affiliation(s)
- Affiefa Yawer
- RECETOX, Faculty of Science, Masaryk University, Kamenice 753/5, building A29, 625 00 Brno, Czech Republic
| | - Eliška Sychrová
- RECETOX, Faculty of Science, Masaryk University, Kamenice 753/5, building A29, 625 00 Brno, Czech Republic
| | - Petra Labohá
- RECETOX, Faculty of Science, Masaryk University, Kamenice 753/5, building A29, 625 00 Brno, Czech Republic
| | - Jan Raška
- RECETOX, Faculty of Science, Masaryk University, Kamenice 753/5, building A29, 625 00 Brno, Czech Republic
| | - Tomáš Jambor
- BioFood Centre, Faculty of Biotechnology and Food Sciences, Slovak University of Agriculture in Nitra, Tr. A. Hlinku 2, 949 76 Nitra, Slovac Republic
| | - Pavel Babica
- RECETOX, Faculty of Science, Masaryk University, Kamenice 753/5, building A29, 625 00 Brno, Czech Republic
| | - Iva Sovadinová
- RECETOX, Faculty of Science, Masaryk University, Kamenice 753/5, building A29, 625 00 Brno, Czech Republic.
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Abitbol J, Beach R, Barr K, Esseltine J, Allman B, Laird D. Cisplatin-induced ototoxicity in organotypic cochlear cultures occurs independent of gap junctional intercellular communication. Cell Death Dis 2020; 11:342. [PMID: 32393745 PMCID: PMC7214471 DOI: 10.1038/s41419-020-2551-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 04/23/2020] [Accepted: 04/23/2020] [Indexed: 12/11/2022]
Abstract
Cisplatin is a very effective chemotherapeutic, but severe and permanent hearing loss remains a prevalent side effect. The processes underpinning cisplatin-induced ototoxicity are not well understood. Gap junction channels composed of connexin (Cx) subunits allow for the passage of small molecules and ions between contacting neighboring cells. These specialized channels have been postulated to enhance cisplatin-induced cell death by spreading “death signals” throughout the supporting cells of the organ of Corti. This study sought to investigate the role of Cx43 in cisplatin-induced ototoxicity using organotypic cochlear cultures from control and two Cx43-mutant mouse strains harboring either a moderate (Cx43I130T/+) or severe (Cx43G60S/+) reduction of Cx43 function. Cochlear cultures from Cx43-mutant mice with a severe reduction in Cx43-based gap junctional intercellular communication (GJIC) had an enhanced number of hair cells that were positive for cleaved caspase 3, a marker of active apoptosis, after cisplatin treatment. In cisplatin-treated organotypic cochlear cultures, there was a decrease in the co-localization of Cx26 and Cx30 compared with untreated cultures, suggesting that cisplatin causes reorganization of connexin composition in supporting cells. Both Cx26 and Cx30 protein expression as well as GJIC were decreased in organotypic cochlear cultures treated with the gap-junction blocker carbenoxolone. When cisplatin and carbenoxolone were co-administered, there were no differences in hair cell loss compared with cisplatin treatment alone. Using cisplatin-treated control and Cx43-ablated organ of Corti derived HEI-OC1 mouse cells, we found that greatly reducing GJIC led to preferential induction of an ER stress pathway. Taken together, this study strongly suggests that inhibition of GJIC in organ of Corti cells does not lead to differential susceptibility to cisplatin-induced ototoxicity. Although cisplatin causes the same degree of cell death in gap junction competent and incompetent cochlear cells, the engagement of the mitochondrial dysregulation and ER stress differs.
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Affiliation(s)
- Julia Abitbol
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5C1, Canada
| | - Rianne Beach
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5C1, Canada
| | - Kevin Barr
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5C1, Canada
| | - Jessica Esseltine
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, NL, A1B 3V6, Canada
| | - Brian Allman
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5C1, Canada
| | - Dale Laird
- Department of Anatomy and Cell Biology, Schulich School of Medicine and Dentistry, University of Western Ontario, London, ON, N6A 5C1, Canada.
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Connexins-Based Hemichannels/Channels and Their Relationship with Inflammation, Seizures and Epilepsy. Int J Mol Sci 2019; 20:ijms20235976. [PMID: 31783599 PMCID: PMC6929063 DOI: 10.3390/ijms20235976] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2019] [Revised: 11/13/2019] [Accepted: 11/20/2019] [Indexed: 12/11/2022] Open
Abstract
Connexins (Cxs) are a family of 21 protein isoforms, eleven of which are expressed in the central nervous system, and they are found in neurons and glia. Cxs form hemichannels (connexons) and channels (gap junctions/electric synapses) that permit functional and metabolic coupling between neurons and astrocytes. Altered Cx expression and function is involved in inflammation and neurological diseases. Cxs-based hemichannels and channels have a relevance to seizures and epilepsy in two ways: First, this pathological condition increases the opening probability of hemichannels in glial cells to enable gliotransmitter release, sustaining the inflammatory process and exacerbating seizure generation and epileptogenesis, and second, the opening of channels favors excitability and synchronization through coupled neurons. These biological events highlight the global pathological mechanism of epilepsy, and the therapeutic potential of Cxs-based hemichannels and channels. Therefore, this review describes the role of Cxs in neuroinflammation and epilepsy and examines how the blocking of channels and hemichannels may be therapeutic targets of anti-convulsive and anti-epileptic treatments.
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14
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Li H, Wang C, He T, Zhao T, Chen YY, Shen YL, Zhang X, Wang LL. Mitochondrial Transfer from Bone Marrow Mesenchymal Stem Cells to Motor Neurons in Spinal Cord Injury Rats via Gap Junction. Am J Cancer Res 2019; 9:2017-2035. [PMID: 31037154 PMCID: PMC6485285 DOI: 10.7150/thno.29400] [Citation(s) in RCA: 138] [Impact Index Per Article: 27.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Accepted: 02/07/2019] [Indexed: 01/04/2023] Open
Abstract
Recent studies have demonstrated that bone marrow mesenchymal stem cells (BMSCs) protect the injured neurons of spinal cord injury (SCI) from apoptosis while the underlying mechanism of the protective effect of BMSCs remains unclear. In this study, we found the transfer of mitochondria from BMSCs to injured motor neurons and detected the functional improvement after transplanting. Methods: Primary rat BMSCs were co-cultured with oxygen-glucose deprivation (OGD) injured VSC4.1 motor neurons or primary cortical neurons. FACS analysis was used to detect the transfer of mitochondria from BMSCs to neurons. The bioenergetics profiling of neurons was detected by Extracellular Flux Analysis. Cell viability and apoptosis were also measured. BMSCs and isolated mitochondria were transplanted into SCI rats. TdT-mediated dUTP nick end labelling staining was used to detect apoptotic neurons in the ventral horn. Immunohistochemistry and Western blotting were used to measure protein expression. Re-myelination was examined by transmission electron microscope. BBB scores were used to assess locomotor function. Results: MitoTracker-Red labelled mitochondria of BMSCs could be transferred to the OGD injured neurons. The gap junction intercellular communication (GJIC) potentiator retinoid acid increased the quantity of mitochondria transfer from BMSCs to neurons, while GJIC inhibitor 18β glycyrrhetinic acid decreased mitochondria transfer. Internalization of mitochondria improved the bioenergetics profile, decreased apoptosis and promoted cell survival in post-OGD motor neurons. Furthermore, both transplantation of mitochondria and BMSCs to the injured spinal cord improved locomotor functional recovery in SCI rats. Conclusions: To our knowledge, this is the first evidence that BMSCs protect against SCI through GJIC to transfer mitochondrial to the injured neurons. Our findings suggested a new therapy strategy of mitochondria transfer for the patients with SCI.
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15
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Dynamic intercellular transport modulates the spatial patterning of differentiation during early neural commitment. Nat Commun 2018; 9:4111. [PMID: 30291250 PMCID: PMC6173785 DOI: 10.1038/s41467-018-06693-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 09/17/2018] [Indexed: 01/01/2023] Open
Abstract
The initiation of heterogeneity within a population of phenotypically identical progenitors is a critical event for the onset of morphogenesis and differentiation patterning. Gap junction communication within multicellular systems produces complex networks of intercellular connectivity that result in heterogeneous distributions of intracellular signaling molecules. In this study, we investigate emergent systems-level behavior of the intercellular network within embryonic stem cell (ESC) populations and corresponding spatial organization during early neural differentiation. An agent-based model incorporates experimentally-determined parameters to yield complex transport networks for delivery of pro-differentiation cues between neighboring cells, reproducing the morphogenic trajectories during retinoic acid-accelerated mouse ESC differentiation. Furthermore, the model correctly predicts the delayed differentiation and preserved spatial features of the morphogenic trajectory that occurs in response to intercellular perturbation. These findings suggest an integral role of gap junction communication in the temporal coordination of emergent patterning during early differentiation and neural commitment of pluripotent stem cells.
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16
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Yin X, Feng L, Ma D, Yin P, Wang X, Hou S, Hao Y, Zhang J, Xin M, Feng J. Roles of astrocytic connexin-43, hemichannels, and gap junctions in oxygen-glucose deprivation/reperfusion injury induced neuroinflammation and the possible regulatory mechanisms of salvianolic acid B and carbenoxolone. J Neuroinflammation 2018; 15:97. [PMID: 29587860 PMCID: PMC5872583 DOI: 10.1186/s12974-018-1127-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Accepted: 03/12/2018] [Indexed: 02/07/2023] Open
Abstract
Background Glia-mediated neuroinflammation is related to brain injury exacerbation after cerebral ischemia/reperfusion (I/R) injury. Astrocytic hemichannels or gap junctions, which were mainly formed by connexin-43, have been implicated in I/R damage. However, the exact roles of astrocytic hemichannels and gap junction in neuroinflammatory responses induced by I/R injury remain unknown. Methods Primary cultured astrocytes were subjected to OGD/R injury, an in vitro model of I/R injury. Salvianolic acid B (SalB) or carbenoxolone (CBX) were applied for those astrocytes. Besides, Cx43 mimetic peptides Gap19 or Gap26 were also applied during OGD/R injury; Cx43 protein levels were determined by western blot and cytoimmunofluorescene staining, hemichannel activities by Ethidium bromide uptake and ATP concentration detection, and gap junction intercellular communication (GJIC) permeability by parachute assay. Further, astrocyte-conditioned medium (ACM) was collected and incubated with microglia. Meanwhile, ATP or apyrase were applied to explore the role of ATP during OGD/R injury. Microglial activation, M1/M2 phenotypes, and M1/M2-related cytokines were detected. Also, microglia-conditioned medium (MEM) was collected and incubated with astrocytes to further investigate its influence on astrocytic hemichannel activity and GJIC permeability. Lastly, effects of ACM and MCM on neuronal viability were detected by flow cytometry. Results We found that OGD/R induced abnormally opened hemichannels with increased ATP release and EtBr uptake but reduced GJIC permeability. WB tests showed decreased astrocytic plasma membrane’s Cx43, while showing an increase in cytoplasma. Treating OGD/R-injured microglia with ATP or OGD/R-ACM induced further microglial activation and secondary pro-inflammatory cytokine release, with the M1 phenotype predominating. Conversely, astrocytes incubated with OGD/R-MCM exhibited increased hemichannel opening but reduced GJIC coupling. Both SalB and CBX inhibited abnormal astrocytic hemichannel opening and ATP release and switched the activated microglial phenotype from M1 to M2, thus providing effective neuroprotection. Application of Gap19 or Gap26 showed similar results with CBX. We also found that OGD/R injury caused both plasma membrane p-Cx43(Ser265) and p-Src(Tyr416) significantly upregulated; application of SalB may be inhibiting Src kinase and attenuating Cx43 internalization. Meanwhile, CBX treatment induced obviously downregulation of p-Cx43(Ser368) and p-PKC(Ser729) protein levels in plasma membrane. Conclusions We propose a vicious cycle exists between astrocytic hemichannel and microglial activation after OGD/R injury, which would aggravate neuroinflammatory responses and neuronal damage. Astrocytic Cx43, hemichannels, and GJIC play critical roles in OGD/R injury-induced neuroinflammatory responses; treatment differentially targeting astrocytic Cx43, hemichannels, and GJIC may provide novel avenues for therapeutics during cerebral I/R injury. Electronic supplementary material The online version of this article (10.1186/s12974-018-1127-3) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Xiang Yin
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Liangshu Feng
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Di Ma
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Ping Yin
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Xinyu Wang
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Shuai Hou
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Yulei Hao
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Jingdian Zhang
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Meiying Xin
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China
| | - Jiachun Feng
- Department of Neurology and Neuroscience Center, the First Hospital of Jilin University, Changchun, Jilin Province, 130021, People's Republic of China.
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Hong K, Cope EL, DeLalio LJ, Marziano C, Isakson BE, Sonkusare SK. TRPV4 (Transient Receptor Potential Vanilloid 4) Channel-Dependent Negative Feedback Mechanism Regulates G q Protein-Coupled Receptor-Induced Vasoconstriction. Arterioscler Thromb Vasc Biol 2018; 38:542-554. [PMID: 29301784 DOI: 10.1161/atvbaha.117.310038] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2017] [Accepted: 12/18/2017] [Indexed: 12/16/2022]
Abstract
OBJECTIVE Several physiological stimuli activate smooth muscle cell (SMC) GqPCRs (Gq protein-coupled receptors) to cause vasoconstriction. As a protective mechanism against excessive vasoconstriction, SMC GqPCR stimulation invokes endothelial cell vasodilatory signaling. Whether Ca2+ influx in endothelial cells contributes to the regulation of GqPCR-induced vasoconstriction remains unknown. Ca2+ influx through TRPV4 (transient receptor potential vanilloid 4) channels is a key regulator of endothelium-dependent vasodilation. We hypothesized that SMC GqPCR stimulation engages endothelial TRPV4 channels to limit vasoconstriction. APPROACH AND RESULTS Using high-speed confocal microscopy to record unitary Ca2+ influx events through TRPV4 channels (TRPV4 sparklets), we report that activation of SMC α1ARs (alpha1-adrenergic receptors) with phenylephrine or thromboxane A2 receptors with U46619 stimulated TRPV4 sparklets in the native endothelium from mesenteric arteries. Activation of endothelial TRPV4 channels did not require an increase in Ca2+ as indicated by the lack of effect of L-type Ca2+ channel activator or chelator of intracellular Ca2+ EGTA-AM. However, gap junction communication between SMCs and endothelial cells was required for phenylephrine activation or U46619 activation of endothelial TRPV4 channels. Lowering inositol 1,4,5-trisphosphate levels with phospholipase C inhibitor or lithium chloride suppressed phenylephrine activation of endothelial TRPV4 sparklets. Moreover, uncaging inositol 1,4,5-trisphosphate profoundly increased TRPV4 sparklet activity. In pressurized arteries, phenylephrine-induced vasoconstriction was followed by a slow, TRPV4-dependent vasodilation, reflecting activation of negative regulatory mechanism. Consistent with these data, phenylephrine induced a significantly higher increase in blood pressure in TRPV4-/- mice. CONCLUSIONS These results demonstrate that SMC GqPCR stimulation triggers inositol 1,4,5-trisphosphate-dependent activation of endothelial TRPV4 channels to limit vasoconstriction.
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Affiliation(s)
- Kwangseok Hong
- From the Robert M. Berne Cardiovascular Research Center (K.H., E.L.C., L.J.D., C.M., B.E.I., S.K.S.), Department of Molecular Physiology and Biological Physics (C.M., B.E.I., S.K.S.), and Department of Pharmacology (L.J.D., S.K.S), University of Virginia-School of Medicine, Charlottesville
| | - Eric L Cope
- From the Robert M. Berne Cardiovascular Research Center (K.H., E.L.C., L.J.D., C.M., B.E.I., S.K.S.), Department of Molecular Physiology and Biological Physics (C.M., B.E.I., S.K.S.), and Department of Pharmacology (L.J.D., S.K.S), University of Virginia-School of Medicine, Charlottesville
| | - Leon J DeLalio
- From the Robert M. Berne Cardiovascular Research Center (K.H., E.L.C., L.J.D., C.M., B.E.I., S.K.S.), Department of Molecular Physiology and Biological Physics (C.M., B.E.I., S.K.S.), and Department of Pharmacology (L.J.D., S.K.S), University of Virginia-School of Medicine, Charlottesville
| | - Corina Marziano
- From the Robert M. Berne Cardiovascular Research Center (K.H., E.L.C., L.J.D., C.M., B.E.I., S.K.S.), Department of Molecular Physiology and Biological Physics (C.M., B.E.I., S.K.S.), and Department of Pharmacology (L.J.D., S.K.S), University of Virginia-School of Medicine, Charlottesville
| | - Brant E Isakson
- From the Robert M. Berne Cardiovascular Research Center (K.H., E.L.C., L.J.D., C.M., B.E.I., S.K.S.), Department of Molecular Physiology and Biological Physics (C.M., B.E.I., S.K.S.), and Department of Pharmacology (L.J.D., S.K.S), University of Virginia-School of Medicine, Charlottesville
| | - Swapnil K Sonkusare
- From the Robert M. Berne Cardiovascular Research Center (K.H., E.L.C., L.J.D., C.M., B.E.I., S.K.S.), Department of Molecular Physiology and Biological Physics (C.M., B.E.I., S.K.S.), and Department of Pharmacology (L.J.D., S.K.S), University of Virginia-School of Medicine, Charlottesville.
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Willebrords J, Maes M, Crespo Yanguas S, Vinken M. Inhibitors of connexin and pannexin channels as potential therapeutics. Pharmacol Ther 2017; 180:144-160. [PMID: 28720428 PMCID: PMC5802387 DOI: 10.1016/j.pharmthera.2017.07.001] [Citation(s) in RCA: 106] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
While gap junctions support the exchange of a number of molecules between neighboring cells, connexin hemichannels provide communication between the cytosol and the extracellular environment of an individual cell. The latter equally holds true for channels composed of pannexin proteins, which display an architecture reminiscent of connexin hemichannels. In physiological conditions, gap junctions are usually open, while connexin hemichannels and, to a lesser extent, pannexin channels are typically closed, yet they can be activated by a number of pathological triggers. Several agents are available to inhibit channels built up by connexin and pannexin proteins, including alcoholic substances, glycyrrhetinic acid, anesthetics and fatty acids. These compounds not always strictly distinguish between gap junctions, connexin hemichannels and pannexin channels, and may have effects on other targets as well. An exception lies with mimetic peptides, which reproduce specific amino acid sequences in connexin or pannexin primary protein structure. In this paper, a state-of-the-art overview is provided on inhibitors of cellular channels consisting of connexins and pannexins with specific focus on their mode-of-action and therapeutic potential.
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Affiliation(s)
- Joost Willebrords
- Department of In Vitro Toxicology and Dermato-cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium
| | - Michaël Maes
- Department of In Vitro Toxicology and Dermato-cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium
| | - Sara Crespo Yanguas
- Department of In Vitro Toxicology and Dermato-cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium
| | - Mathieu Vinken
- Department of In Vitro Toxicology and Dermato-cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, Brussels, Belgium.
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Leybaert L, Lampe PD, Dhein S, Kwak BR, Ferdinandy P, Beyer EC, Laird DW, Naus CC, Green CR, Schulz R. Connexins in Cardiovascular and Neurovascular Health and Disease: Pharmacological Implications. Pharmacol Rev 2017; 69:396-478. [PMID: 28931622 PMCID: PMC5612248 DOI: 10.1124/pr.115.012062] [Citation(s) in RCA: 171] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Connexins are ubiquitous channel forming proteins that assemble as plasma membrane hemichannels and as intercellular gap junction channels that directly connect cells. In the heart, gap junction channels electrically connect myocytes and specialized conductive tissues to coordinate the atrial and ventricular contraction/relaxation cycles and pump function. In blood vessels, these channels facilitate long-distance endothelial cell communication, synchronize smooth muscle cell contraction, and support endothelial-smooth muscle cell communication. In the central nervous system they form cellular syncytia and coordinate neural function. Gap junction channels are normally open and hemichannels are normally closed, but pathologic conditions may restrict gap junction communication and promote hemichannel opening, thereby disturbing a delicate cellular communication balance. Until recently, most connexin-targeting agents exhibited little specificity and several off-target effects. Recent work with peptide-based approaches has demonstrated improved specificity and opened avenues for a more rational approach toward independently modulating the function of gap junctions and hemichannels. We here review the role of connexins and their channels in cardiovascular and neurovascular health and disease, focusing on crucial regulatory aspects and identification of potential targets to modify their function. We conclude that peptide-based investigations have raised several new opportunities for interfering with connexins and their channels that may soon allow preservation of gap junction communication, inhibition of hemichannel opening, and mitigation of inflammatory signaling.
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Affiliation(s)
- Luc Leybaert
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Paul D Lampe
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Stefan Dhein
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Brenda R Kwak
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Peter Ferdinandy
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Eric C Beyer
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Dale W Laird
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Christian C Naus
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Colin R Green
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
| | - Rainer Schulz
- Physiology Group, Department of Basic Medical Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium (L.L.); Translational Research Program, Fred Hutchinson Cancer Research Center, Seattle, Washington (P.D.L.); Institute for Pharmacology, University of Leipzig, Leipzig, Germany (S.D.); Department of Pathology and Immunology, Department of Medical Specialization-Cardiology, University of Geneva, Geneva, Switzerland (B.R.K.); Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary (P.F.); Pharmahungary Group, Szeged, Hungary (P.F.); Department of Pediatrics, University of Chicago, Chicago, Illinois (E.C.B.); Department of Anatomy and Cell Biology, University of Western Ontario, Dental Science Building, London, Ontario, Canada (D.W.L.); Cellular and Physiological Sciences, Faculty of Medicine, The University of British Columbia, Vancouver, British Columbia, Canada (C.C.N.); Department of Ophthalmology and The New Zealand National Eye Centre, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand (C.R.G.); and Physiologisches Institut, Justus-Liebig-Universität Giessen, Giessen, Germany (R.S.)
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Abstract
Many patients with lung cancer, breast cancer, and melanoma develop brain metastases that are resistant to conventional therapy. The median survival for untreated patients is 1 to 2 months, which may be extended to 6 months with surgery, radiotherapy, and chemotherapy. The outcome of metastasis depends on multiple interactions of unique metastatic cells with host homeostatic mechanisms which the tumor cells exploit for their survival and proliferation. The blood-brain barrier is leaky in metastases that are larger than 0.5-mm diameter because of production of vascular endothelial growth factor by metastatic cells. Brain metastases are surrounded and infiltrated by microglia and activated astrocytes. The interaction with astrocytes leads to up-regulation of multiple genes in the metastatic cells, including several survival genes that are responsible for the increased resistance of tumor cells to cytotoxic drugs. These findings substantiate the importance of the "seed and soil" hypothesis and that successful treatment of brain metastases must include targeting of the organ microenvironment.
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21
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Lin Q, Liu Z, Ling F, Xu G. Astrocytes protect glioma cells from chemotherapy and upregulate survival genes via gap junctional communication. Mol Med Rep 2015; 13:1329-35. [PMID: 26676970 DOI: 10.3892/mmr.2015.4680] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2015] [Accepted: 11/19/2015] [Indexed: 11/06/2022] Open
Abstract
Gliomas are the most common type of primary brain tumor. Using current standard treatment regimens, the prognosis of patients with gliomas remains poor, which is predominantly due to the resistance of glioma cells to chemotherapy. The organ microenvironment has been implicated in the pathogenesis and survival of tumor cells. Thus, the aim of the present study was to test the hypothesis that astrocytes (the housekeeping cells of the brain microenvironment) may protect glioma cells from chemotherapy and to investigate the underlying mechanism. Immunofluorescent and scanning electron microscopy demonstrated that glioma cells were surrounded and infiltrated by activated astrocytes. In vitro co-culture of glioma cells with astrocytes significantly reduced the cytotoxic effects on glioma cells caused by various chemotherapeutic agents, as demonstrated by fluorescein isothiocyanate-propidium iodide flow cytometry. Transwell experiments indicated that this protective effect was dependent on physical contact and the gap junctional communication (GJC) between astrocytes and glioma cells. Microarray expression profiling further revealed that astrocytes upregulated the expression levels of various critical survival genes in the glioma cells via GJC. The results of the present study indicated that the organ microenvironment may affect the biological behavior of tumor cells and suggest a novel mechanism of resistance in glioma cells, which may be of therapeutic relevance clinically.
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Affiliation(s)
- Qingtang Lin
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100054, P.R. China
| | - Zhao Liu
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100054, P.R. China
| | - Feng Ling
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100054, P.R. China
| | - Geng Xu
- Department of Neurosurgery, Xuanwu Hospital, Capital Medical University, Beijing 100054, P.R. China
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Multiplexed Fluid Flow Device to Study Cellular Response to Tunable Shear Stress Gradients. Ann Biomed Eng 2015; 44:2261-72. [PMID: 26589597 DOI: 10.1007/s10439-015-1500-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Accepted: 10/31/2015] [Indexed: 02/03/2023]
Abstract
Endothelial cells (ECs) line the interior of blood and lymphatic vessels and experience spatially varying wall shear stress (WSS) as an intrinsic part of their physiological function. How ECs, and mammalian cells generally, sense spatially varying WSS remains poorly understood, due in part to a lack of convenient tools for exposing cells to spatially varying flow patterns. We built a multiplexed device, termed a 6-well impinging flow chamber, that imparts controlled WSS gradients to a six-well tissue culture plate. Using this device, we investigated the migratory response of lymphatic microvascular ECs, umbilical vein ECs, primary fibroblasts, and epithelial cells to WSS gradients on hours to days timescales. We observed that lymphatic microvascular ECs migrate upstream, against the direction of flow, a response that was unique among all the cells types investigated here. Time-lapse, live cell imaging revealed that the microtubule organizing center relocated to the upstream side of the nucleus in response to the applied WSS gradient. To further demonstrate the utility of our device, we screened for the involvement of canonical signaling pathways in mediating this upstream migratory response. These data highlight the importance of WSS magnitude and WSS spatial gradients in dictating the cellular response to fluid flow.
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23
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Yu F, Yan H, Nie W, Zhu J. Connexin43 knockdown in bone marrow‑derived dendritic cells by small interfering RNA leads to a diminished T-cell stimulation. Mol Med Rep 2015; 13:895-900. [PMID: 26648560 DOI: 10.3892/mmr.2015.4593] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 08/25/2015] [Indexed: 11/06/2022] Open
Abstract
Dendritic cells, the most powerful type of antigen‑presenting cells, have the unique ability to induce primary immune responses. Connexin43 expression is upregulated to increase gap junctions when immune cells are exposed to inflammatory factors. The present study applied small‑interfering RNA (siRNA) to decrease connexin43 expression. The results showed that silencing of connexin43 using siRNA resulted in arrest of bone marrow‑derived dendritic cell (BM‑DC) maturation as evidenced by reduced expression of major histocompatibility complex II, CD40, CD80 and CD86. Functionally, connexin43‑silenced BM‑DC showed a markedly decreased capability to induce T-cell stimulation. In conclusion, the present study demonstrated that antigens present on BM‑DCs can be suppressed by connexin43 knockdown in BM‑DCs. The present study therefore presented an effective method to modulate the immunology of BM‑DCs.
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Affiliation(s)
- Fuling Yu
- Cardiovascular Department, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, P.R. China
| | - Hui Yan
- Cardiovascular Department, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, P.R. China
| | - Wencheng Nie
- Cardiovascular Department, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, P.R. China
| | - Jianhua Zhu
- Cardiovascular Department, The First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou, Zhejiang 310003, P.R. China
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Zachova K, Krupka M, Raska M. Antigen Cross-Presentation and Heat Shock Protein-Based Vaccines. Arch Immunol Ther Exp (Warsz) 2015; 64:1-18. [DOI: 10.1007/s00005-015-0370-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2015] [Accepted: 08/31/2015] [Indexed: 12/15/2022]
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Murrant CL, Sarelius IH. Local control of blood flow during active hyperaemia: what kinds of integration are important? J Physiol 2015; 593:4699-711. [PMID: 26314391 DOI: 10.1113/jp270205] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2015] [Accepted: 08/05/2015] [Indexed: 01/06/2023] Open
Abstract
The focus of this review is on local mechanisms modifying arteriolar resistance to match blood flow to metabolism. In skeletal muscle many local mediators are known, including K(+) , nitric oxide (NO), purines and prostaglandins. Each accounts for about 30% of the response; it is widely held that these act redundantly: this concept awaits systematic testing. Understanding signal integration also requires consideration of microvascular network morphology in relation to local communication pathways between endothelial and smooth muscle cells (which are critical for many local responses, including dilatation to skeletal muscle contraction) and in relation to the spread of vasodilator signals up- and downstream throughout the network. Mechanisms mediating the spread of dilatation from local to remote sites have been well studied using acetylcholine (ACh), but remote dilatations to contraction of skeletal muscle fibres also occur. Importantly, these mechanisms clearly differ from those initiated by ACh, but much remains undefined. Furthermore, capillaries contribute to metabolic dilatation as they dilate arterioles directly upstream in response to vasoactive agents or contraction of adjacent muscle fibres. Given the dispersed arrangement of motor units, precise matching of flow to metabolism is not attainable unless signals are initiated only by 'active' capillaries. As motor units are recruited, signals that direct blood flow towards these active fibres will eventually be supported by local and spreading responses in the arterioles associated with those fibres. Thus, mechanisms of integration of vasodilator signalling across elements of the microvasculature remain an important area of focus for new studies.
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Affiliation(s)
- Coral L Murrant
- Department of Human Health and Nutritional Science, University of Guelph, Guelph, ON, Canada
| | - Ingrid H Sarelius
- Department of Pharmacology and Physiology, University of Rochester, Rochester, NY, USA
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18β-glycyrrhetinic acid suppresses experimental autoimmune encephalomyelitis through inhibition of microglia activation and promotion of remyelination. Sci Rep 2015; 5:13713. [PMID: 26329786 PMCID: PMC4557075 DOI: 10.1038/srep13713] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 08/06/2015] [Indexed: 01/09/2023] Open
Abstract
Microglia are intrinsic immune cells in the central nervous system (CNS). The under controlled microglia activation plays important roles in inflammatory demyelination diseases, such as multiple sclerosis (MS). However, the means to modulate microglia activation as a therapeutic modality and the underlying mechanisms remain elusive. Here we show that administration of 18β-glycyrrhetinic acid (GRA), by using both preventive and therapeutic treatment protocols, significantly suppresses disease severity of experimental autoimmune encephalomyelitis (EAE) in C57BL/6 mice. The treatment effect of GRA on EAE is attributed to its regulatory effect on microglia. GRA-modulated microglia significantly decreased pro-inflammatory profile in the CNS through suppression of MAPK signal pathway. The ameliorated CNS pro-inflammatory profile prevented the recruitment of encephalitogenic T cells into the CNS, which alleviated inflammation-induced demyelination. In addition, GRA treatment promoted remyelination in the CNS of EAE mice. The induced remyelination can be mediated by the overcome of inflammation-induced blockade of brain-derived neurotrophic factor expression in microglia, as well as enhancing oligodendrocyte precursor cell proliferation. Collectively, our results demonstrate that GRA-modulated microglia suppresses EAE through inhibiting microglia activation-mediated CNS inflammation, and promoting neuroprotective effect of microglia, which represents a potential therapeutic strategy for MS and maybe other neuroinflammatory diseases associated with microglia activation.
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Sovadinova I, Babica P, Böke H, Kumar E, Wilke A, Park JS, Trosko JE, Upham BL. Phosphatidylcholine Specific PLC-Induced Dysregulation of Gap Junctions, a Robust Cellular Response to Environmental Toxicants, and Prevention by Resveratrol in a Rat Liver Cell Model. PLoS One 2015; 10:e0124454. [PMID: 26023933 PMCID: PMC4449167 DOI: 10.1371/journal.pone.0124454] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2014] [Accepted: 03/10/2015] [Indexed: 12/04/2022] Open
Abstract
Dysregulation of gap junctional intercellular communication (GJIC) has been associated with different pathologies, including cancer; however, molecular mechanisms regulating GJIC are not fully understood. Mitogen Activated Protein Kinase (MAPK)-dependent mechanisms of GJIC-dysregulation have been well-established, however recent discoveries have implicated phosphatidylcholine-specific phospholipase C (PC-PLC) in the regulation of GJIC. What is not known is how prevalent these two signaling mechanisms are in toxicant/toxin-induced dysregulation of GJIC, and do toxicants/toxins work through either signaling mechanisms or both, or through alternative signaling mechanisms. Different chemical toxicants were used to assess whether they dysregulate GJIC via MEK or PC-PLC, or both Mek and PC-PLC, or through other signaling pathways, using a pluripotent rat liver epithelial oval-cell line, WB-F344. Epidermal growth factor, 12-O-tetradecanoylphorbol-13-acetate, thrombin receptor activating peptide-6 and lindane regulated GJIC through a MEK1/2-dependent mechanism that was independent of PC-PLC; whereas PAHs, DDT, PCB 153, dicumylperoxide and perfluorodecanoic acid inhibited GJIC through PC-PLC independent of Mek. Dysregulation of GJIC by perfluorooctanoic acid and R59022 required both MEK1/2 and PC-PLC; while benzoylperoxide, arachidonic acid, 18β-glycyrrhetinic acid, perfluorooctane sulfonic acid, 1-monolaurin, pentachlorophenol and alachlor required neither MEK1/2 nor PC-PLC. Resveratrol prevented dysregulation of GJIC by toxicants that acted either through MEK1/2 or PC-PLC. Except for alachlor, resveratrol did not prevent dysregulation of GJIC by toxicants that worked through PC-PLC-independent and MEK1/2-independent pathways, which indicated at least two other, yet unidentified, pathways that are involved in the regulation of GJIC. In conclusion: the dysregulation of GJIC is a contributing factor to the cancer process; however the underlying mechanisms by which gap junction channels are closed by toxicants vary. Thus, accurate assessments of risk posed by toxic agents, and the role of dietary phytochemicals play in preventing or reversing the effects of these agents must take into account the specific mechanisms involved in the cancer process.
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Affiliation(s)
- Iva Sovadinova
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- Research Centre for Toxic Compounds in the Environment—RECETOX, Masaryk University, Kamenice 5, CZ62500, Brno, Czech Republic
| | - Pavel Babica
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- Department of Experimental Phycology and Ecotoxicology, Institute of Botany ASCR, Lidicka 25/27, CZ60200, Brno, Czech Republic
| | - Hatice Böke
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Esha Kumar
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Andrew Wilke
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Joon-Suk Park
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- Laboratory Animal Center, Daegu-Gyeongbuk Medical Innovation Foundation, Daegu, Korea
| | - James E. Trosko
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
| | - Brad L. Upham
- Department of Pediatrics & Human Development; Center for Integrative Toxicology; and the Food Safety & Toxicology Center, Michigan State University, East Lansing, Michigan, 48824, United States of America
- * E-mail:
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Kim D, Seo Y, Kwon S. Role of gap junction communication in hepatocyte/fibroblast co-cultures: Implications for hepatic tissue engineering. BIOTECHNOL BIOPROC E 2015. [DOI: 10.1007/s12257-014-0595-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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29
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Two-step inhibitory effect of kanzo on oxytocin-induced and prostaglandin F2α-induced uterine myometrial contractions. J Nat Med 2014; 68:550-60. [DOI: 10.1007/s11418-014-0835-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2013] [Accepted: 03/25/2014] [Indexed: 10/25/2022]
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30
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Siewert B, Csuk R. Membrane damaging activity of a maslinic acid analog. Eur J Med Chem 2014; 74:1-6. [PMID: 24440377 DOI: 10.1016/j.ejmech.2013.12.031] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 11/28/2013] [Accepted: 12/22/2013] [Indexed: 02/06/2023]
Abstract
Close inspection of human ovarian cancer cells A2780 in the course of an antitumor screening using maslinic acid analogs revealed for one of the compounds, 4-oxa-4-phenyl-butyl 2,3-dihydroxy-olean-12-en-28-oate (1), an unusual behavior. During the incubation of the cells with 1, at the perimeter of the cells or close by crystals were formed consisting of cholesterol and excess 1. Compound 1 was incorporated into the cell's membrane followed by an extrusion of cholesterol from the lipid rafts. As a consequence of the alterations of the cell membrane, a volume decrease was initiated that triggered apoptosis; this extends previous models on apoptosis initiating mechanisms.
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Affiliation(s)
- Bianka Siewert
- Bereich Organische Chemie, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Straße 2, D-06120 Halle (Saale), Germany
| | - René Csuk
- Bereich Organische Chemie, Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Straße 2, D-06120 Halle (Saale), Germany.
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Tittarelli A, Mendoza-Naranjo A, Farías M, Guerrero I, Ihara F, Wennerberg E, Riquelme S, Gleisner A, Kalergis A, Lundqvist A, López MN, Chambers BJ, Salazar-Onfray F. Gap junction intercellular communications regulate NK cell activation and modulate NK cytotoxic capacity. THE JOURNAL OF IMMUNOLOGY 2013; 192:1313-9. [PMID: 24376266 DOI: 10.4049/jimmunol.1301297] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Gap junctions (GJs) mediate intercellular communication between adjacent cells. Previously, we showed that connexin 43 (Cx43), the main GJ protein in the immune system, mediates Ag transfer between human dendritic cells (DCs) and is recruited to the immunological synapse during T cell priming. This crosstalk contributed to T cell activation, intracellular Ca(2+) responses, and cytokine release. However, the role of GJs in NK cell activation by DCs and NK cell-mediated cytotoxicity against tumor cells remains unknown. In this study, we found polarization of Cx43 at the NK/DC and NK/tumor cell-contact sites, accompanied by the formation of functional GJs between NK/DCs and NK/tumor cells, respectively. Cx43-GJ-mediated intercellular communication (GJIC) between human NK and DCs was bidirectional. Blockage of Cx43-GJIC inhibited NK cell activation, though it affected neither the phenotype nor the function of DCs. Cx43 knockdown or inhibition using mimetic peptides greatly reduced CD69 and CD25 expression and IFN-γ release by DC-stimulated NK cells. Moreover, blocking Cx43 strongly inhibited the NK cell-mediated tumor cell lysis associated with inhibition of granzyme B activity and Ca(2+) influx. Our data identify a novel and active role for Cx43-GJIC in human NK cell activation and antitumor effector functions that may be important for the design of new immune therapeutic strategies.
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Affiliation(s)
- Andrés Tittarelli
- Faculty of Medicine, Institute of Biomedical Sciences, University of Chile, 8380453 Santiago, Chile
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Isometric Contraction of Dupuytren’s Myofibroblasts Is Inhibited by Blocking Intercellular Junctions. J Invest Dermatol 2013; 133:2664-2671. [DOI: 10.1038/jid.2013.219] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2012] [Revised: 04/09/2013] [Accepted: 04/09/2013] [Indexed: 01/22/2023]
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Connexins form functional hemichannels in porcine ciliary epithelium. Exp Eye Res 2013; 118:20-9. [PMID: 24262135 DOI: 10.1016/j.exer.2013.11.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2013] [Revised: 11/05/2013] [Accepted: 11/11/2013] [Indexed: 01/20/2023]
Abstract
The expression of connexins in the ciliary epithelium is consistent with gap junctions between the pigmented (PE) and nonpigmented ciliary epithelium (NPE) that form when connexon hemichannels from adjacent cells pair to form a channel. Here we present evidence that suggests undocked connexons may form functional hemichannels that permit exchange of substances between NPE and the aqueous humor. Intact porcine eyes were perfused via the ciliary artery and propidium iodide (PI) (MW 668) was added to the aqueous humor compartment as a tracer. After calcium-free solution containing PI was introduced into the aqueous humor compartment for 30 min, fluorescence microscopy revealed PI in the NPE cell layer. PI entry into the NPE was inhibited by calcium and by the connexin antagonist 18α-glycyrrhetinic acid (18-AGA). Studies also were carried out with cultured porcine NPE. Under normal conditions, little PI entered the cultured cells but calcium-free medium stimulated PI accumulation and the entry was inhibited by 18-AGA. In cells loaded with calcein (MW 622), calcium-free solution stimulated calcein exit. 18-AGA partially suppressed calcein exit in calcium-free medium. Connexin 43 and connexin 50 proteins were detected by western blot analysis in both native and cultured NPE. In the intact eye, immunolocalization studies revealed connexin 50 at the basolateral, aqueous humor-facing, margin of the NPE. In contrast, connexin 43 was observed at the junction of the PE and NPE layer and on the basolateral membrane of PE. The results point to functional hemichannels at the NPE basolateral surface. It is feasible that hemichannels might contribute to the transfer of substances between the ciliary epithelium cytoplasm and aqueous humor.
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Chapman K, Holmes M, Seckl J. 11β-hydroxysteroid dehydrogenases: intracellular gate-keepers of tissue glucocorticoid action. Physiol Rev 2013; 93:1139-206. [PMID: 23899562 DOI: 10.1152/physrev.00020.2012] [Citation(s) in RCA: 562] [Impact Index Per Article: 51.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Glucocorticoid action on target tissues is determined by the density of "nuclear" receptors and intracellular metabolism by the two isozymes of 11β-hydroxysteroid dehydrogenase (11β-HSD) which catalyze interconversion of active cortisol and corticosterone with inert cortisone and 11-dehydrocorticosterone. 11β-HSD type 1, a predominant reductase in most intact cells, catalyzes the regeneration of active glucocorticoids, thus amplifying cellular action. 11β-HSD1 is widely expressed in liver, adipose tissue, muscle, pancreatic islets, adult brain, inflammatory cells, and gonads. 11β-HSD1 is selectively elevated in adipose tissue in obesity where it contributes to metabolic complications. Similarly, 11β-HSD1 is elevated in the ageing brain where it exacerbates glucocorticoid-associated cognitive decline. Deficiency or selective inhibition of 11β-HSD1 improves multiple metabolic syndrome parameters in rodent models and human clinical trials and similarly improves cognitive function with ageing. The efficacy of inhibitors in human therapy remains unclear. 11β-HSD2 is a high-affinity dehydrogenase that inactivates glucocorticoids. In the distal nephron, 11β-HSD2 ensures that only aldosterone is an agonist at mineralocorticoid receptors (MR). 11β-HSD2 inhibition or genetic deficiency causes apparent mineralocorticoid excess and hypertension due to inappropriate glucocorticoid activation of renal MR. The placenta and fetus also highly express 11β-HSD2 which, by inactivating glucocorticoids, prevents premature maturation of fetal tissues and consequent developmental "programming." The role of 11β-HSD2 as a marker of programming is being explored. The 11β-HSDs thus illuminate the emerging biology of intracrine control, afford important insights into human pathogenesis, and offer new tissue-restricted therapeutic avenues.
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Affiliation(s)
- Karen Chapman
- Endocrinology Unit, Centre for Cardiovascular Science, The Queen’s Medical Research Institute, University of Edinburgh, Edinburgh, United Kingdom
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35
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Polycyclic aromatic hydrocarbon-induced signaling events relevant to inflammation and tumorigenesis in lung cells are dependent on molecular structure. PLoS One 2013; 8:e65150. [PMID: 23755184 PMCID: PMC3670909 DOI: 10.1371/journal.pone.0065150] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 04/23/2013] [Indexed: 12/12/2022] Open
Abstract
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental and occupational toxicants, which are a major human health concern in the U.S. and abroad. Previous research has focused on the genotoxic events caused by high molecular weight PAHs, but not on non-genotoxic events elicited by low molecular weight PAHs. We used an isomeric pair of low molecular weight PAHs, namely 1-Methylanthracene (1-MeA) and 2-Methylanthracene (2-MeA), in which only 1-MeA possessed a bay-like region, and hypothesized that 1-MeA, but not 2-MeA, would affect non-genotoxic endpoints relevant to tumor promotion in murine C10 lung cells, a non-tumorigenic type II alveolar pneumocyte and progenitor cell type of lung adenocarcinoma. The non-genotoxic endpoints assessed were dysregulation of gap junction intercellular communication function and changes in the major pulmonary connexin protein, connexin 43, using fluorescent redistribution and immunoblots, activation of mitogen activated protein kinases (MAPK) using phosphospecific MAPK antibodies for immunoblots, and induction of inflammatory genes using quantitative RT-PCR. 2-MeA had no effect on any of the endpoints, but 1-MeA dysregulated gap junctional communication in a dose and time dependent manner, reduced connexin 43 protein expression, and altered membrane localization. 1-MeA also activated ERK1/2 and p38 MAP kinases. Inflammatory genes, such as cyclooxygenase 2, and chemokine ligand 2 (macrophage chemoattractant 2), were also upregulated in response to 1-MeA only. These results indicate a possible structure-activity relationship of these low molecular weight PAHs relevant to non-genotoxic endpoints of the promoting aspects of cancer. Therefore, our novel findings may improve the ability to predict outcomes for future studies with additional toxicants and mixtures, identify novel targets for biomarkers and chemotherapeutics, and have possible implications for future risk assessment for these PAHs.
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Goerke SM, Plaha J, Hager S, Strassburg S, Torio-Padron N, Stark GB, Finkenzeller G. Human endothelial progenitor cells induce extracellular signal-regulated kinase-dependent differentiation of mesenchymal stem cells into smooth muscle cells upon cocultivation. Tissue Eng Part A 2012; 18:2395-405. [PMID: 22731749 DOI: 10.1089/ten.tea.2012.0147] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Neovascularization represents an important issue in tissue-engineering applications, since survival of implanted cells strongly relies on sufficient oxygen and nutrient supply. We have recently observed that human bone marrow-derived mesenchymal stem cells (MSCs) support neovessel formation originating from coimplanted endothelial cells (ECs) in vivo, suggesting that MSCs may function as perivascular cells by investing and stabilizing nascent EC-derived neovessels. In this study, we investigated EC-induced mural cell differentiation of MSCs in vitro. For this purpose, endothelial progenitor cells (EPCs) from two different origins, namely adult peripheral blood (pbEPCs) and neonatal cord blood (cbEPCs), or human umbilical vein endothelial cells (HUVECs), were cocultured with human MSCs to analyze the effect on MSC differentiation toward a smooth muscle cell (SMC)/pericyte phenotype. EPCs as well as HUVECs increased alpha-smooth muscle actin expression in MSCs upon cocultivation in a time-dependent manner. This effect was strongly dependent on direct cell-to-cell contact and extracellular signal-regulated kinase (ERK) signaling, but was not mediated by heterotypic gap junction communication. Beyond enhanced SMC marker gene expression in MSCs, EPCs also enhanced the functional characteristics of cocultured MSCs by increasing their ability to attach to EC tubes in vitro. In conclusion, our study has shown that EPCs from adult peripheral blood as well as from cord blood commit cocultivated MSCs toward an SMC/pericyte phenotype in a cell-contact- and ERK-dependent manner.
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Affiliation(s)
- Sebastian M Goerke
- Department of Plastic and Hand Surgery, University of Freiburg Medical Center, Freiburg, Germany
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37
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Trudeau K, Muto T, Roy S. Downregulation of mitochondrial connexin 43 by high glucose triggers mitochondrial shape change and cytochrome C release in retinal endothelial cells. Invest Ophthalmol Vis Sci 2012; 53:6675-81. [PMID: 22915032 DOI: 10.1167/iovs.12-9895] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
PURPOSE To determine connexin 43 (Cx43) localization in mitochondria and investigate the effects of high glucose (HG) on mitochondrial Cx43 (mtCx43) expression and whether altered mtCx43 channel activity is involved in promoting apoptosis in retinal endothelial cells. METHODS MtCx43 localization was determined using immunostaining, green fluorescent protein (GFP)-tagged Cx43 followed by confocal imaging, and Western blot analysis using protein isolated from mitochondria of rat retinal endothelial cells (RRECs). To assess HG effects on mtCx43 expression, RRECs were grown in normal (5 mM) or HG (30 mM) medium for 7 days, and mtCx43 protein level assessed by Western blot analysis. To determine if mtCx43 channel inhibition affected mitochondrial morphology, RRECs grown sparsely were left untreated or treated with β-glycerrhetinic acid (β-GA), an inhibitor of connexin channels, and imaged using confocal microscopy. Additionally, mitochondria isolated from RRECs were treated with β-GA, and cytochrome c release assessed by Western blot. RESULTS Cx43 localization on the mitochondria of RRECs was confirmed with immunofluorescence staining using Cx43 antibody and GFP-tagged Cx43 imaged in live cells. Western blot analysis indicated that Cx43 was located primarily on the inner mitochondrial membrane, and mtCx43 protein level was significantly reduced in RRECs grown in HG condition. Treatment of RRECs with β-GA significantly decreased mtCx43 phosphorylation, induced mitochondrial fragmentation, and isolated mitochondria treated with β-GA showed increased cytochrome c release. CONCLUSIONS HG-induced downregulation of mtCx43 protein resulting in decreased channel activity may promote mitochondrial morphology changes and cytochrome c release, suggesting a novel mechanism for hyperglycemia-induced apoptosis in diabetic retinopathy.
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Affiliation(s)
- Kyle Trudeau
- Department of Medicine and Ophthalmology, Boston University School of Medicine, Boston, MA 02118, USA
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38
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Lam CH, Hansen EA, Janson C, Bryan A, Hubel A. The characterization of arachnoid cell transport II: paracellular transport and blood-cerebrospinal fluid barrier formation. Neuroscience 2012; 222:228-38. [PMID: 22814001 DOI: 10.1016/j.neuroscience.2012.06.065] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 06/28/2012] [Accepted: 06/29/2012] [Indexed: 01/01/2023]
Abstract
We used an immortalized arachnoid cell line to test the arachnoid barrier properties and paracellular transport. The permeabilities of urea, mannitol, and inulin through monolayers were 2.9 ± 1.1 × 10(-6), 0.8 ± .18 × 10(-6), 1.0 ± .29 × 10(-6)cm/s. Size differential permeability testing with dextran clarified the arachnoidal blood-cerebrospinal fluid (CSF) barrier limit and established a rate of transcellular transport to be about two orders of magnitude slower than paracellular transport in a polyester membrane diffusion chamber. The theoretical pore size for paracellular space is 11Å and the occupancy to length ratio is 0.8 and 0.72 cm(-1) for urea and mannitol respectively. The permeability of the monolayer was not significantly different from apical to basal and vice versa. Gap junctions may have a role in contributing to barrier formation. Although the upregulation of claudin by dexamethasone did not significantly alter paracellular transport, increasing intracellular cAMP decreased mannitol permeability. Calcium modulated paracellular transport, but only selectively with the ion chelator, EDTA, and with disruption of intracellular stores. The blood-CSF barrier at the arachnoid is anatomically and physiologically different from the vascular-based blood-brain barrier, but is similarly subject to modulation. We describe the basic paracellular transport characteristics of this CSF "sink" of the brain which will allow for a better description of mass and constitutive balance within the intracranial compartment.
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Affiliation(s)
- C H Lam
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, MN 55455, United States.
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39
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Primary cultures of embryonic chick lens cells as a model system to study lens gap junctions and fiber cell differentiation. J Membr Biol 2012; 245:357-68. [PMID: 22797938 DOI: 10.1007/s00232-012-9458-y] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 06/20/2012] [Indexed: 01/31/2023]
Abstract
A major limitation in lens gap junction research has been the lack of experimentally tractable ex vivo systems to study the formation and regulation of fiber-type gap junctions. Although immortalized lens-derived cell lines are amenable to both gene transfection and siRNA-mediated knockdown, to our knowledge none are capable of undergoing appreciable epithelial-to-fiber differentiation. Lens central epithelial explants have the converse limitation. A key advance in the field was the development of a primary embryonic chick lens cell culture system by Drs. Sue Menko and Ross Johnson. Unlike central epithelial explants, these cultures also include cells from the peripheral (preequatorial and equatorial) epithelium, which is the most physiologically relevant population for the study of fiber-type gap junction formation. We have modified the Menko/Johnson system and refer to our cultures as dissociated cell-derived monolayer cultures (DCDMLs). We culture DCDMLs without serum to mimic the avascular lens environment and on laminin, the major matrix component of the lens capsule. Here, I review the features of the DCDML system and how we have used it to study lens gap junctions and fiber cell differentiation. Our results demonstrate the power of DCDMLs to generate new findings germane to the mammalian lens and how these cultures can be exploited to conduct experiments that would be impossible, prohibitively expensive and/or difficult to interpret using transgenic animals in vivo.
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SUN YAN, ZHAO XIAOPING, YAO YUTING, QI XINYI, YUAN YAOZONG, HU YU. Connexin 43 interacts with Bax to regulate apoptosis of pancreatic cancer through a gap junction-independent pathway. Int J Oncol 2012; 41:941-8. [DOI: 10.3892/ijo.2012.1524] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2011] [Accepted: 04/24/2012] [Indexed: 11/05/2022] Open
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41
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Neschadim A, Wang JCM, Lavie A, Medin JA. Bystander killing of malignant cells via the delivery of engineered thymidine-active deoxycytidine kinase for suicide gene therapy of cancer. Cancer Gene Ther 2012; 19:320-7. [PMID: 22388453 DOI: 10.1038/cgt.2012.4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Activity and specificity of chemotherapeutic agents against solid tumors can be augmented via the targeted or localized delivery of 'suicide' genes. Selective activation of specific prodrugs in cells expressing the 'suicide' gene drives their elimination by apoptosis, while also enabling the killing of adjacent bystander cells. Strong bystander effects can compensate for poor 'suicide' gene delivery, and depend on the prodrugs used and mechanisms for the acquisition of activated drug by the bystander population, such as the presence of gap junctional intercellular communications. Although a number of 'suicide' gene therapies for cancer have been developed and characterized, such as herpes simplex virus-derived thymidine kinase (HSV-tk)-based activation of ganciclovir, their limited success highlights the need for the development of more robust approaches. Limiting activation kinetics and evolution of chemoresistance are major obstacles. Here we describe 'suicide' gene therapy of cancer based on the lentivirus-mediated delivery of a thymidine-active human deoxycytidine kinase variant. This enzyme possesses substrate plasticity that enables it to activate a multitude of prodrugs, some with distinct mechanisms of action. We evaluated the magnitude and mechanisms of bystander effects induced by different prodrugs, and show that when used in combination, they can synergistically enhance the bystander effect while avoiding off-target toxicity.
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Affiliation(s)
- A Neschadim
- Department of Medical Biophysics, University Health Network, University of Toronto, Toronto, Ontario, Canada
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42
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Lan WR, Hou CJY, Yen CH, Shih BF, Wang AM, Lee TY, Tsai CH, Yeh HI. Effects of carbenoxolone on flow-mediated vasodilatation in healthy adults. Am J Physiol Heart Circ Physiol 2011; 301:H1166-72. [DOI: 10.1152/ajpheart.00967.2010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Gap junctions play a key role in maintaining the functional integrity of the vascular wall. Using carbenoxolone (CBX) as a gap junction blocker, we aimed to assess the contribution of gap junctions in the vascular wall to flow-mediated vasodilatation (FMD) in healthy adults. Percentage FMD (%FMD) and circulating vasoactive molecules/activity, including atrial natriuretic peptide (ANP), B-type natriuretic peptide (BNP), aldosterone, cortisol, plasma renin activity (PRA), and endothelin (ET-1), were measured in 25 healthy volunteers (mean age: 30.1 ± 5.4 yr; 14 males) before and after oral administration of CBX (100 mg). %FMD decreased after ingestion of CBX (9.71 ± 3.1 vs. 3.40 ± 2.0%; P < 0.0001). The levels of ANP, BNP, cortisol, and ET-1 remained stationary, while both PRA and aldosterone decreased ( P < 0.005) after CBX ingestion. Blood pressure and heart rate were minimally changed by CBX. Inhibition of gap junctional communication by CBX impairs FMD in healthy persons, suggesting that physiologically, vascular gap junctions participate in the maintenance of FMD. CBX does not induce the release of vasoconstricting molecules or enhance vasoconstriction, suggesting that inhibition of gap junctional communication by CBX underlies the impairment of FMD. Therefore, administering CBX in FMD examination can be a way to follow the effect of gap junctions on endothelial function, but further work remains to verify the specificity of CBX effect.
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Affiliation(s)
- Wei-Ren Lan
- Cardiovascular Section, Department of Internal Medicine, and
| | - Charles Jia-Yin Hou
- Cardiovascular Section, Department of Internal Medicine, and
- Mackay Medicine, Nursing and Management College; and
| | - Chih-Hsuan Yen
- Cardiovascular Section, Department of Internal Medicine, and
| | | | | | | | - Cheng-Ho Tsai
- Cardiovascular Section, Department of Internal Medicine, and
| | - Hung-I Yeh
- Cardiovascular Section, Department of Internal Medicine, and
- Mackay Medical College, Taipei, Taiwan
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Wyrwoll CS, Holmes MC, Seckl JR. 11β-hydroxysteroid dehydrogenases and the brain: from zero to hero, a decade of progress. Front Neuroendocrinol 2011; 32:265-86. [PMID: 21144857 PMCID: PMC3149101 DOI: 10.1016/j.yfrne.2010.12.001] [Citation(s) in RCA: 168] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 12/01/2010] [Accepted: 12/01/2010] [Indexed: 12/11/2022]
Abstract
Glucocorticoids have profound effects on brain development and adult CNS function. Excess or insufficient glucocorticoids cause myriad abnormalities from development to ageing. The actions of glucocorticoids within cells are determined not only by blood steroid levels and target cell receptor density, but also by intracellular metabolism by 11β-hydroxysteroid dehydrogenases (11β-HSD). 11β-HSD1 regenerates active glucocorticoids from their inactive 11-keto derivatives and is widely expressed throughout the adult CNS. Elevated hippocampal and neocortical 11β-HSD1 is observed with ageing and causes cognitive decline; its deficiency prevents the emergence of cognitive defects with age. Conversely, 11β-HSD2 is a dehydrogenase, inactivating glucocorticoids. The major central effects of 11β-HSD2 occur in development, as expression of 11β-HSD2 is high in fetal brain and placenta. Deficient feto-placental 11β-HSD2 results in a life-long phenotype of anxiety and cardiometabolic disorders, consistent with early life glucocorticoid programming.
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Affiliation(s)
- Caitlin S Wyrwoll
- Endocrinology Unit, Centre for Cardiovascular Science, Queen's Medical Research Institute, The University of Edinburgh, Edinburgh EH16 4TJ, UK.
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44
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Sena K, Angle SR, Kanaji A, Aher C, Karwo DG, Sumner DR, Virdi AS. Low-intensity pulsed ultrasound (LIPUS) and cell-to-cell communication in bone marrow stromal cells. ULTRASONICS 2011; 51:639-644. [PMID: 21333315 DOI: 10.1016/j.ultras.2011.01.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/02/2010] [Accepted: 01/22/2011] [Indexed: 05/30/2023]
Abstract
Low-intensity pulsed ultrasound (LIPUS) is an established therapy for fracture repair and has been used widely in the clinics, but its underlying mechanism of action remains unclear. The aim of the current research was to determine the effect of LIPUS on gap junctional cell-to-cell intercellular communication in rat bone marrow stromal cells (BMSC) in vitro and to determine whether the ability of BMSCs to communicate by gap junctions would affect their response to LIPUS. Single or daily-multiple LIPUS treatment at 1.5MHz, 30mW/cm(2), for 20min was applied to BMSC. We demonstrated that BMSC form functional gap junctions and single LIPUS treatment significantly increased the intracellular dye transfer between BMSC. In addition, activated phosphorylation of ERK1/2 and p38 by LIPUS stimulation was diminished when cells were treated with a gap junction inhibitor 18β-glycyrrhetinic acid (18β). We further demonstrated that 18β diminished the significant increase in alkaline phosphatase activity following LIPUS stimulation. These results suggest a potential role of gap junctional cell-to-cell intercellular communication on the effects of LIPUS in BMSC.
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Affiliation(s)
- Kotaro Sena
- Department of Anatomy and Cell Biology, Rush University Medical Center, Chicago, IL 60612, United States.
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45
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Astrocytes upregulate survival genes in tumor cells and induce protection from chemotherapy. Neoplasia 2011; 13:286-98. [PMID: 21390191 DOI: 10.1593/neo.11112] [Citation(s) in RCA: 190] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 01/24/2011] [Accepted: 01/27/2011] [Indexed: 11/18/2022] Open
Abstract
In the United States, more than 40% of cancer patients develop brain metastasis. The median survival for untreated patients is 1 to 2 months, which may be extended to 6 months with conventional radiotherapy and chemotherapy. The growth and survival of metastasis depend on the interaction of tumor cells with host factors in the organ microenvironment. Brain metastases are surrounded and infiltrated by activated astrocytes and are highly resistant to chemotherapy. We report here that coculture of human breast cancer cells or lung cancer cells with murine astrocytes (but not murine fibroblasts) led to the up-regulation of survival genes, including GSTA5, BCL2L1, and TWIST1, in the tumor cells. The degree of up-regulation directly correlated with increased resistance to all tested chemotherapeutic agents. We further show that the up-regulation of the survival genes and consequent resistance are dependent on the direct contact between the astrocytes and tumor cells through gap junctions and are therefore transient. Knocking down these genes with specific small interfering RNA rendered the tumor cells sensitive to chemotherapeutic agents. These data clearly demonstrate that host cells in the microenvironment influence the biologic behavior of tumor cells and reinforce the contention that the organ microenvironment must be taken into consideration during the design of therapy.
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Desforges B, Savarin P, Bounedjah O, Delga S, Hamon L, Curmi PA, Pastré D. Gap junctions favor normal rat kidney epithelial cell adaptation to chronic hypertonicity. Am J Physiol Cell Physiol 2011; 301:C705-16. [PMID: 21677260 DOI: 10.1152/ajpcell.00128.2011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Upon hypertonic stress most often resulting from high salinity, cells need to balance their osmotic pressure by accumulating neutral osmolytes called compatible osmolytes like betaine, myo-inositol, and taurine. However, the massive uptake of compatible osmolytes is a slow process compared with other defense mechanisms related to oxidative or heat stress. This is especially critical for cycling cells as they have to double their volume while keeping a hospitable intracellular environment for the molecular machineries. Here we propose that clustered cells can accelerate the supply of compatible osmolytes to cycling cells via the transit, mediated by gap junctions, of compatible osmolytes from arrested to cycling cells. Both experimental results in epithelial normal rat kidney cells and theoretical estimations show that gap junctions indeed play a key role in cell adaptation to chronic hypertonicity. These results can provide basis for a better understanding of the functions of gap junctions in osmoregulation not only for the kidney but also for many other epithelia. In addition to this, we suggest that cancer cells that do not communicate via gap junctions poorly cope with hypertonic environments thus explaining the rare occurrence of cancer coming from the kidney medulla.
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Affiliation(s)
- Bénédicte Desforges
- Laboratoire Structure-Activité des Biomolécules Normales et Pathologiques, Institut National de la Santé et de la Recherche Médicale U, Université Evry-Val d’Essonne, France
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Dey A, Kusljic S, Lang RJ, Exintaris B. Role of connexin 43 in the maintenance of spontaneous activity in the guinea pig prostate gland. Br J Pharmacol 2011; 161:1692-707. [PMID: 20735413 DOI: 10.1111/j.1476-5381.2010.01001.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND AND PURPOSE To investigate the role of connexin 43 in the maintenance of spontaneous activity in prostate tissue from young and old guinea pigs. EXPERIMENTAL APPROACH Conventional intracellular microelectrode and tension recording techniques, coupled with Western blot analysis and immunohistochemistry for connexin 43 (CX43) were used. The effects of three gap junction uncouplers, 18β glycyrrhetinic acid (10 µM, 40 µM), carbenoxolone (10 µM, 50 µM) and octanol (0.5 mM, 1 mM), were studied in cells displaying slow wave activity and on spontaneously contracting tissue from prostate glands of young (2-5 months) and old (9-16 months) guinea pigs. KEY RESULTS 18β Glycyrrhetinic acid (40 µM), carbenoxolone (50 µM) or octanol (0.5 mM) abolished slow wave activity in prostate tissue from young and old guinea pigs and depolarized membrane potential by approximately 5 mV. These treatments also abolished all contractions in both sets of prostate tissue. These effects were reversed upon washout. Western blot analysis and CX43 immunohistochemistry showed that there was no age-related difference in the expression and distribution of CX43 in prostate tissues. CONCLUSION AND IMPLICATIONS When gap junctional communication via CX43 was disrupted, spontaneous activity was abolished at a cellular and whole tissue level; CX43 is therefore essential for the maintenance of spontaneous slow wave activity and subsequent contractile activity in the guinea pig prostate gland.
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Affiliation(s)
- Anupa Dey
- Medicinal Chemistry & Drug Action, Monash Institute of Pharmaceutical Sciences, Parkville, Victoria, Australia
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Abstract
Gap junctions are aggregates of intercellular channels that permit direct cell-cell transfer of ions and small molecules. Initially described as low-resistance ion pathways joining excitable cells (nerve and muscle), gap junctions are found joining virtually all cells in solid tissues. Their long evolutionary history has permitted adaptation of gap-junctional intercellular communication to a variety of functions, with multiple regulatory mechanisms. Gap-junctional channels are composed of hexamers of medium-sized families of integral proteins: connexins in chordates and innexins in precordates. The functions of gap junctions have been explored by studying mutations in flies, worms, and humans, and targeted gene disruption in mice. These studies have revealed a wide diversity of function in tissue and organ biology.
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Bao B, Jiang J, Yanase T, Nishi Y, Morgan JR. Connexon-mediated cell adhesion drives microtissue self-assembly. FASEB J 2010; 25:255-64. [PMID: 20876208 DOI: 10.1096/fj.10-155291] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Microtissue self-assembly is thought to be driven primarily by cadherins, while connexons have been examined mainly in intercellular coupling. We investigated whether connexon 43 (Cx43)-mediated cell adhesion modulates self-assembly of human KGN granulosa cells, normal human fibroblasts (NHFs), and MCF-7 breast cancer cells seeded into nonadhesive agarose gels. We found that treatment with anti-Cx43 E2 (112 μg/ml), which suppresses Cx43 docking, significantly inhibited the kinetics of KGN and NHF self-assembly compared to the preimmune sera control (41.1 ± 4.5 and 24.5 ± 10.4% at 8 h, respectively). Likewise, gap junction inhibitor carbenoxolone also inhibited self-assembly of KGN, NHF, and MCF-7 cells in a dose-dependent manner that was specific to cell type. In contrast, Gap26 connexin mimetic peptide, which inhibits channel permeability but not docking, accelerated self-assembly of KGN and NHF microtissues. Experiments using selective enzymatic digestion of cell adhesion molecules and neutralizing N-cadherin antibodies further showed that self-assembly was comparably disrupted by inhibiting connexin- and cadherin-mediated adhesion. These findings demonstrate that connexon-mediated cell adhesion and intercellular communication differentially influence microtissue self-assembly, and that their contributions are comparable to those of cadherins.
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Affiliation(s)
- Brian Bao
- Department of Molecular Pharmacology, Physiology, and Biotechnology, Center for Biomedical Engineering, Brown University, Providence, RI 02912, USA
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Lin Q, Balasubramanian K, Fan D, Kim SJ, Guo L, Wang H, Bar-Eli M, Aldape KD, Fidler IJ. Reactive astrocytes protect melanoma cells from chemotherapy by sequestering intracellular calcium through gap junction communication channels. Neoplasia 2010; 12:748-54. [PMID: 20824051 PMCID: PMC2933695 DOI: 10.1593/neo.10602] [Citation(s) in RCA: 158] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2010] [Revised: 06/08/2010] [Accepted: 06/10/2010] [Indexed: 12/18/2022]
Abstract
Brain metastases are highly resistant to chemotherapy. Metastatic tumor cells are known to exploit the host microenvironment for their growth and survival. We report here that melanoma brain metastases are surrounded and infiltrated by activated astrocytes, and we hypothesized that these astrocytes can play a role similar to their established ability to protect neurons from apoptosis. In coculture experiments, astrocytes, but not fibroblasts, reduced apoptosis in human melanoma cells treated with various chemotherapeutic drugs. This chemoprotective effect was dependent on physical contact and gap junctional communication between astrocytes and tumor cells. Moreover, the protective effect of astrocytes resulted from their sequestering calcium from the cytoplasm of tumor cells. These data suggest that brain tumors can, in principle, harness the neuroprotective effects of reactive astrocytes for their own survival and implicate a heretofore unrecognized mechanism for resistance in brain metastasis that might be of relevance in the clinic.
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Affiliation(s)
- Qingtang Lin
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | | | - Dominic Fan
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Sun-Jin Kim
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Lixia Guo
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Hua Wang
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Menashe Bar-Eli
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Kenneth D Aldape
- Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Isaiah J Fidler
- Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
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