1
|
Zhong C, Liang G, Li P, Shi K, Li F, Zhou J, Xu D. Inflammatory response: The target for treating hyperpigmentation during the repair of a burn wound. Front Immunol 2023; 14:1009137. [PMID: 36817442 PMCID: PMC9929571 DOI: 10.3389/fimmu.2023.1009137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Accepted: 01/04/2023] [Indexed: 02/04/2023] Open
Abstract
Hyperpigmentation is a common complication in patients with burn injuries during wound healing; however, the mechanisms underlying its occurrence and development remain unclear. Recently, postinflammatory hyperpigmentation (PIH) was found to result from overproduction of melanin. Local or systemic inflammatory responses are often observed in patients who develop hyperpigmentation. However, we lack studies on the relationship between PIH and burn injury. Therefore, we comprehensively reviewed the existing literature on the melanogenesis of the skin, inflammatory mechanisms in pigmentation, and local or systemic alteration in inflammatory cytokines in patients suffering from burn trauma to elucidate the relationship between PIH and burn injury. We believe that this review will guide further research on regulating melanin production in the burn management process.
Collapse
Affiliation(s)
- Chi Zhong
- Department of Plastic Surgery, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Geao Liang
- Department of Plastic Surgery, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Peiting Li
- Department of Plastic Surgery, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Ke Shi
- Department of Plastic Surgery, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Fuyin Li
- Department of Plastic Surgery, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Jianda Zhou
- Department of Plastic Surgery, The Third Xiangya Hospital, Central South University, Changsha, China
| | - Dan Xu
- Department of Plastic Surgery, The Third Xiangya Hospital, Central South University, Changsha, China
| |
Collapse
|
2
|
Amrollahi P, Zheng W, Monk C, Li CZ, Hu TY. Nanoplasmonic Sensor Approaches for Sensitive Detection of Disease-Associated Exosomes. ACS APPLIED BIO MATERIALS 2021; 4:6589-6603. [PMID: 35006963 PMCID: PMC9130051 DOI: 10.1021/acsabm.1c00113] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Exosomes are abundantly secreted by most cells that carry membrane and cytosolic factors that can reflect the physiologic state of their source cells and thus have strong potential to serve as biomarkers for early diagnosis, disease staging, and treatment monitoring. However, traditional diagnostic or prognostic applications that might use exosomes are hindered by the lack of rapid and sensitive assays that can exploit their biological information. An array of assay approaches have been developed to address this deficit, including those that integrate immunoassays with nanoplasmonic sensors to measure changes in optical refractive indexes in response to the binding of low concentrations of their targeted molecules. These sensors take advantage of enhanced and tunable interactions between the electron clouds of nanoplasmonic particles and structures and incident electromagnetic radiation to enable isolation-free and ultrasensitive quantification of disease-associated exosome biomarkers present in complex biological samples. These unique advantages make nanoplasmonic sensing one of the most competitive approaches available for clinical applications and point-of-care tests that evaluate exosome-based biomarkers. This review will briefly summarize the origin and clinical utility of exosomes and the limitations of current isolation and analysis approaches before reviewing the specific advantages and limitations of nanoplasmonic sensing devices and indicating what additional developments are necessary to allow the translation of these approaches into clinical applications.
Collapse
Affiliation(s)
- Pouya Amrollahi
- Center of Cellular and Molecular Diagnosis, Tulane University, New Orleans, Louisiana 70118, United States
- School of Biological and Health Systems Engineering, Arizona State University, Tempe, Arizona 85281, United States
| | - Wenshu Zheng
- Center of Cellular and Molecular Diagnosis, Tulane University, New Orleans, Louisiana 70118, United States
| | - Chandler Monk
- Center of Cellular and Molecular Diagnosis, Tulane University, New Orleans, Louisiana 70118, United States
| | - Chen-Zhong Li
- Center of Cellular and Molecular Diagnosis, Tulane University, New Orleans, Louisiana 70118, United States
| | - Tony Ye Hu
- Center of Cellular and Molecular Diagnosis, Tulane University, New Orleans, Louisiana 70118, United States
| |
Collapse
|
3
|
Zhu F, Miao Y, Cheng M, Ye X, Chen A, Zheng G, Tian X. The CACNA1A Mutant Disrupts Lysosome Calcium Homeostasis in Cerebellar Neurons and the Resulting Endo-Lysosomal Fusion Defect Can be Improved by Calcium Modulation. Neurochem Res 2021; 47:249-263. [PMID: 34476720 DOI: 10.1007/s11064-021-03438-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 08/23/2021] [Accepted: 08/25/2021] [Indexed: 11/24/2022]
Abstract
Mutations in P/Q type voltage gated calcium channel (VGCC) lead severe human neurological diseases such as episodic ataxia 2, familial hemiplegic migraine 1, absence epilepsy, progressive ataxia and spinocerebellar ataxia 6. The pathogenesis of these diseases remains unclear. Mice with spontaneous mutation in the Cacna1a gene encoding the pore-forming subunit of P/Q type VGCC also exhibit ataxia, epilepsy and neurodegeneration. Based on the previous work showing that the P/Q type VGCC in neurons regulates lysosomal fusion through its calcium channel activity on lysosomes, we utilized CACNA1A mutant mice to further investigate the mechanism by which P/Q-type VGCCs regulate lysosomal function and neuronal homeostasis. We found CACNA1A mutant neurons have reduced lysosomal calcium storage without changing the resting calcium concentration in cytoplasm and the acidification of lysosomes. Immunohistochemistry and transmission electron microscopy reveal axonal degeneration due to lysosome dysfunction in the CACNA1A mutant cerebella. The calcium modulating drug thapsigargin, by depleting the ER calcium store, which locally increases the calcium concentration can alleviate the defective lysosomal fusion in mutant neurons. We propose a model that in cerebellar neurons, P/Q-type VGCC maintains the integrity of the nervous system by regulating lysosomal calcium homeostasis to affect lysosomal fusion, which in turn regulates multiple important cellular processes such as autophagy and endocytosis. This study helps us to better understand the pathogenesis of P/Q-type VGCC related neurodegenerative diseases and provides a feasible direction for future pharmacological treatment.
Collapse
Affiliation(s)
- Feng Zhu
- Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Institute of Materia Medica, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China.,Department of Pharmacy, Hangzhou Medical College, Hangzhou, 310013, China
| | - Yunping Miao
- Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Institute of Materia Medica, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China.,Department of Pharmacy, Hangzhou Medical College, Hangzhou, 310013, China
| | - Min Cheng
- Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Institute of Materia Medica, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China.,Department of Pharmacy, Hangzhou Medical College, Hangzhou, 310013, China
| | - Xiaodi Ye
- Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Institute of Materia Medica, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China.,Department of Pharmacy, Hangzhou Medical College, Hangzhou, 310013, China
| | - Aiying Chen
- Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Institute of Materia Medica, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China.,Department of Pharmacy, Hangzhou Medical College, Hangzhou, 310013, China
| | - Gaoli Zheng
- National Zhejiang Center for Safety Evaluation of New Drugs, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China
| | - Xuejun Tian
- Key Laboratory of Neuropsychiatric Drug Research of Zhejiang Province, Institute of Materia Medica, Hangzhou Medical College (Zhejiang Academy of Medical Sciences), Hangzhou, 310013, China. .,Department of Pharmacy, Hangzhou Medical College, Hangzhou, 310013, China. .,Life Sciences Institute and Innovation Center for Cell Biology, Zhejiang University, Hangzhou, 310058, China.
| |
Collapse
|
4
|
Bueschbell B, Manga P, Penner E, Schiedel AC. Evidence for Protein-Protein Interaction between Dopamine Receptors and the G Protein-Coupled Receptor 143. Int J Mol Sci 2021; 22:ijms22158328. [PMID: 34361094 PMCID: PMC8348196 DOI: 10.3390/ijms22158328] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Revised: 07/28/2021] [Accepted: 07/29/2021] [Indexed: 12/12/2022] Open
Abstract
Protein-protein interactions between G protein-coupled receptors (GPCRs) can augment their functionality and increase the repertoire of signaling pathways they regulate. New therapeutics designed to modulate such interactions may allow for targeting of a specific GPCR activity, thus reducing potential for side effects. Dopamine receptor (DR) heteromers are promising candidates for targeted therapy of neurological conditions such as Parkinson's disease since current treatments can have severe side effects. To facilitate development of such therapies, it is necessary to identify the various DR binding partners. We report here a new interaction partner for DRD2 and DRD3, the orphan receptor G protein-coupled receptor 143 (GPR143), an atypical GPCR that plays multiple roles in pigment cells and is expressed in several regions of the brain. We previously demonstrated that the DRD2/ DRD3 antagonist pimozide also modulates GPR143 activity. Using confocal microscopy and two FRET methods, we observed that the DRs and GPR143 colocalize and interact at intracellular membranes. Furthermore, co-expression of wildtype GPR143 resulted in a 57% and 67% decrease in DRD2 and DRD3 activity, respectively, as determined by β-Arrestin recruitment assay. GPR143-DR dimerization may negatively modulate DR activity by changing affinity for dopamine or delaying delivery of the DRs to the plasma membrane.
Collapse
Affiliation(s)
- Beatriz Bueschbell
- Center for Neuroscience and Cell Biology, University of Coimbra, 3004-504 Coimbra, Portugal;
- PhD Programme in Experimental Biology and Biomedicine, Institute for Interdisciplinary Research (IIIUC), University of Coimbra, Casa Costa Alemão, 3030-789 Coimbra, Portugal
| | - Prashiela Manga
- Ronald O. Perelman Department of Dermatology, Grossman School of Medicine, New York University, New York, NY 10016, USA;
| | - Erika Penner
- Department of Pharmaceutical & Medicinal Chemistry, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany;
| | - Anke C. Schiedel
- Department of Pharmaceutical & Medicinal Chemistry, Pharmaceutical Institute, University of Bonn, D-53121 Bonn, Germany;
- Correspondence:
| |
Collapse
|
5
|
Current and emerging treatments for albinism. Surv Ophthalmol 2020; 66:362-377. [PMID: 33129801 DOI: 10.1016/j.survophthal.2020.10.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 10/07/2020] [Accepted: 10/21/2020] [Indexed: 12/24/2022]
Abstract
Albinism is a group of rare inherited disorders arising from impairment of melanin biosynthesis. The reduction of melanin synthesis leads to hypopigmentation of the skin and eyes. A wide range of ophthalmic manifestations arise from albinism, including reduction of visual acuity, nystagmus, strabismus, iris translucency, foveal hypoplasia, fundus hypopigmentation, and abnormal decussation of retinal ganglion cell axons at the optic chiasm. Currently, albinism is incurable, and treatment aims either surgically or pharmacologically to optimize vision and protect the skin; however, novel therapies that aim to directly address the molecular errors of albinism, such as l-dihydroxyphenylalanine and nitisinone, are being developed and have entered human trials though with limited success. Experimental gene-based strategies for editing the genetic errors in albinism have also met early success in animal models. The emergence of these new therapeutic modalities represents a new era in the management of albinism. We focus on the known genetic subtypes, clinical assessment, and existing and emerging therapeutic options for the nonsyndromic forms of albinism.
Collapse
|
6
|
Tian X, Cui Z, Liu S, Zhou J, Cui R. Melanosome transport and regulation in development and disease. Pharmacol Ther 2020; 219:107707. [PMID: 33075361 DOI: 10.1016/j.pharmthera.2020.107707] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 10/10/2020] [Accepted: 10/13/2020] [Indexed: 02/06/2023]
Abstract
Melanosomes are specialized membrane-bound organelles that synthesize and organize melanin, ultimately providing color to the skin, hair, and eyes. Disorders in melanogenesis and melanosome transport are linked to pigmentary diseases, such as Hermansky-Pudlak syndrome, Chediak-Higashi syndrome, and Griscelli syndrome. Clinical cases of these pigmentary diseases shed light on the molecular mechanisms that control melanosome-related pathways. However, only an improved understanding of melanogenesis and melanosome transport will further the development of diagnostic and therapeutic approaches. Herein, we review the current literature surrounding melanosomes with particular emphasis on melanosome membrane transport and cytoskeleton-mediated melanosome transport. We also provide perspectives on melanosome regulatory mechanisms which include hormonal action, inflammation, autophagy, and organelle interactions.
Collapse
Affiliation(s)
- Xiaoyu Tian
- Institute of Biomedical Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Ziyong Cui
- Harvard College, Cambridge, MA 02138, United States of America
| | - Song Liu
- Institute of Biomedical Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan 250014, China
| | - Jun Zhou
- Institute of Biomedical Sciences, Shandong Provincial Key Laboratory of Animal Resistance Biology, Collaborative Innovation Center of Cell Biology in Universities of Shandong, College of Life Sciences, Shandong Normal University, Jinan 250014, China; State Key Laboratory of Medicinal Chemical Biology, College of Life Sciences, Nankai University, Tianjin 300071, China.
| | - Rutao Cui
- Skin Disease Research Institute, The 2nd Hospital, Zhejiang University, Hangzhou 310058, China.
| |
Collapse
|
7
|
Lu G, Zhou B, He Y, Liu H, Luo S, Amos CI, Lee JE, Yang K, Qureshi A, Han J, Wei Q. Novel genetic variants of PIP5K1C and MVB12B of the endosome-related pathway predict cutaneous melanoma-specific survival. Am J Cancer Res 2020; 10:3382-3394. [PMID: 33163277 PMCID: PMC7642651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 07/22/2020] [Indexed: 06/11/2023] Open
Abstract
Endosomes regulate cell polarity, adhesion, signaling, immunity, and tumor progression, which may influence cancer outcomes. Here we evaluated associations between 36,068 genetic variants of 228 endosome-related pathway genes and cutaneous melanoma disease-specific survival (CMSS) using genotyping data from two previously published genome-wide association studies. The discovery dataset included 858 CM patients with 95 deaths from The University of Texas MD Anderson Cancer Center, and the replication dataset included 409 CM patients with 48 deaths from the Nurses' Health Study (NHS) and the Health Professionals Follow-up Study (HPFS). In multivariate Cox proportional hazards regression analysis, we found that two novel SNPs (PIP5K1C rs11666894 A>C and MVB12B rs12376285 C>T) predicted CMSS, with adjusted hazards ratios of 1.47 (95% confidence interval = 1.15-1.89 and P = 0.002) and 1.73 (1.30-2.31 and 0.0002), respectively. Combined analysis of risk genotypes of these two SNPs revealed a dose-dependent decrease in CMSS associated with an increased number of risk genotypes (P trend = 0.0002). Subsequent expression quantitative trait loci (eQTL) analysis revealed that PIP5K1C rs11666894 was associated with mRNA expression levels in lymphoblastoid cell lines from 373 European descendants (P<0.0001) and that MVB12B rs12376285 was associated with mRNA expression levels in cultured fibroblasts from 605 European-Americans (P<0.0001). Our findings suggest that novel genetic variants of PIP5K1C and MVB12B in the endosome-related pathway genes may be promising prognostic biomarkers for CMSS, but these results need to be validated in future larger studies.
Collapse
Affiliation(s)
- Guiqing Lu
- Department of Dermatology, BenQ Medical Center, The Affiliated BenQ Hospital of Nanjing Medical UniversityNanjing 210019, Jiangsu, China
- Duke Cancer Institute, Duke University Medical CenterDurham, NC 27710, USA
- Department of Population Health Sciences, Duke University School of MedicineDurham, NC 27710, USA
| | - Bingrong Zhou
- Duke Cancer Institute, Duke University Medical CenterDurham, NC 27710, USA
- Department of Population Health Sciences, Duke University School of MedicineDurham, NC 27710, USA
| | - Yuanmin He
- Duke Cancer Institute, Duke University Medical CenterDurham, NC 27710, USA
- Department of Population Health Sciences, Duke University School of MedicineDurham, NC 27710, USA
| | - Hongliang Liu
- Duke Cancer Institute, Duke University Medical CenterDurham, NC 27710, USA
- Department of Population Health Sciences, Duke University School of MedicineDurham, NC 27710, USA
| | - Sheng Luo
- Department of Biostatistics and Bioinformatics, Duke University School of MedicineDurham, NC 27710, USA
| | - Christopher I Amos
- Institute for Clinical and Translational Research, Baylor College of MedicineHouston, TX 77030, USA
| | - Jeffrey E Lee
- Department of Surgical Oncology, The University of Texas M.D. Anderson Cancer CenterHouston, TX 77030, USA
| | - Keming Yang
- Department of Nutrition, Harvard T.H. Chan School of Public HealthBoston, MA, USA
| | - Abrar Qureshi
- Department of Dermatology, Warren Alpert Medical School, Brown UniversityProvidence, RI 02903, USA
| | - Jiali Han
- Channing Division of Network Medicine, Department of Medicine, Brigham and Women’s HospitalBoston, MA 02115, USA
- Department of Epidemiology, Fairbanks School of Public Health, Indiana UniversityIndianapolis, IN 46202, USA
| | - Qingyi Wei
- Duke Cancer Institute, Duke University Medical CenterDurham, NC 27710, USA
- Department of Population Health Sciences, Duke University School of MedicineDurham, NC 27710, USA
- Department of Medicine, Duke University School of MedicineDurham, NC 27710, USA
| |
Collapse
|
8
|
Bebelman MP, Crudden C, Pegtel DM, Smit MJ. The Convergence of Extracellular Vesicle and GPCR Biology. Trends Pharmacol Sci 2020; 41:627-640. [PMID: 32711926 DOI: 10.1016/j.tips.2020.07.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 07/01/2020] [Accepted: 07/02/2020] [Indexed: 02/07/2023]
Abstract
Transmembrane receptors, of which G protein-coupled receptors (GPCRs) constitute the largest group, typically act as cellular antennae that reside at the plasma membrane (PM) to collect and interpret information from the extracellular environment. The discovery of cell-released extracellular vesicles (EVs) has added a new dimension to intercellular communication. These unique nanocarriers reflect cellular topology and can systemically transport functionally competent transmembrane receptors, ligands, and a cargo of signal proteins. Recent developments hint at roles for GPCRs in the EV life cycle and, conversely, at roles for EVs in GPCR signal transduction. We highlight key points of convergence, discuss their relevance to current GPCR and EV paradigms, and speculate on how this intersection could lend itself to future therapeutic avenues.
Collapse
Affiliation(s)
- Maarten P Bebelman
- Division of Medicinal Chemistry, Amsterdam Institute for Molecular Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands; Department of Pathology, Cancer Center Amsterdam, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Caitrin Crudden
- Department of Pathology, Cancer Center Amsterdam, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - D Michiel Pegtel
- Department of Pathology, Cancer Center Amsterdam, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands
| | - Martine J Smit
- Division of Medicinal Chemistry, Amsterdam Institute for Molecular Life Sciences, Vrije Universiteit Amsterdam, Amsterdam, The Netherlands.
| |
Collapse
|
9
|
Figueroa AG, McKay BS. A G-Protein Coupled Receptor and Macular Degeneration. Cells 2020; 9:cells9040910. [PMID: 32276449 PMCID: PMC7226737 DOI: 10.3390/cells9040910] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2020] [Revised: 03/31/2020] [Accepted: 04/07/2020] [Indexed: 12/12/2022] Open
Abstract
Age-related macular degeneration (AMD) is a leading cause of irreversible blindness in the world. The risk of AMD increases with age and is most common among the white population. Here, we discuss the convergence of factors related to race, pigmentation, and susceptibility to AMD, where the primary defect occurs in retinal support cells, the retinal pigment epithelium (RPE). We explore whether the observed racial bias in AMD incidence is related to innate differences in the basal level of pigmentation between races, and whether the pigmentation pathway activity in the RPE might protect from retinal degeneration. More specifically, we explore whether the downstream signaling activity of GPR143, a G-protein coupled receptor in the pigmentation pathway, might underly the racial bias of AMD and be a target to prevent the disease. Lastly, we summarize the past findings of a large retrospective study that investigated the relationship between the stimulation of GPR143 with L-DOPA, the pigmentation pathway, and AMD, to potentially help develop new ways to prevent or treat AMD. The reader of this review will come to understand the racial bias of AMD, which is related to the function of the RPE.
Collapse
|
10
|
Autophagy, lysosome dysfunction and mTOR inhibition in MNU-induced photoreceptor cell damage. Tissue Cell 2019; 61:98-108. [PMID: 31759414 DOI: 10.1016/j.tice.2019.09.008] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 09/21/2019] [Accepted: 09/23/2019] [Indexed: 01/03/2023]
Abstract
Progressive photoreceptor death is the main cause of retinal degeneration diseases. Determining the underlying mechanism of this process is essential for therapy improvement. Autophagy has long been considered to be involved in neuronal degeneration diseases, and the regulation of autophagy is thought to have potential implications for neurodegenerative disease therapies. However, whether autophagy is protective or destructive varies among diseases and is controversial. In the present study, we established an N-methyl-N-nitrosourea (MNU)-induced photoreceptor cell damage model in vitro that faithfully replicated photoreceptor cell death in retinal degeneration diseases. Cell viability was tested by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxy-methoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assays. Reactive oxygen species (ROS) levels were assessed through 2,7-dichlorodihydrofluorescein diacetate (DCFH-DA) fluorescence. Autophagy was confirmed by observing autophagosomes using transmission electron microscopy (TEM). A lysosome tracker was used to identify acidic lysosomes in cells. We also measured the expression of some proteins related to autophagy, apoptosis and lysosomal degradation by western blot and immunofluorescence assays. We found that MNU could decrease photoreceptor cell viability in a time- and dose-dependent manner, and this change was accompanied by concomitant increases in ROS and the expression of the apoptosis-inducing protein cleaved caspase-3. Moreover, autophagy was activated by MNU treatment during this process. Inhibition of autophagy with 3-methyladenine accelerated cell damage. Lysosome dysfunction was confirmed by autophagosome enlargement and increased cathepsin expression, which was accompanied by mTOR dephosphorylation. In conclusion, autophagy was activated through inhibition of the PI3K/mTOR pathway in the context of MNU-induced photoreceptor cell death. Prolonged mTOR dephosphorylation and autophagy activation resulted in autophagic vacuole accumulation, as indicated by inefficient degradation in lysosomes, and further led to apoptosis.
Collapse
|
11
|
Goshima Y, Watanabe S, Seki E, Koga M, Masukawa D, Nakamura F, Komori T, Arai N. Immunoreactivity of a G protein-coupled l-DOPA receptor GPR143, in Lewy bodies. Neurosci Res 2018; 148:49-53. [PMID: 30590075 DOI: 10.1016/j.neures.2018.12.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 12/12/2018] [Accepted: 12/19/2018] [Indexed: 01/26/2023]
Abstract
l-3,4-Dihydroxyphenylalanine (l-DOPA) has been believed to be an inert amino acid precursor of dopamine, and is the most effective therapeutic agent in Parkinson's disease (PD). We proposed l-DOPA as a neurotransmitter in the central nervous system. Recently, the ocular albinism 1 gene product, OA1/GPR143 (GPR143), was identified as a receptor for l-DOPA. In this study, we examined by generating anti-human GPR143 antibody, the localization of GPR143-immunoreactive signals in the brains from control and PD subjects. GPR143-immunoreactive signals were detected throughout the entire midbrain including substantia nigra pars compacta. In the PD brains, we found that GPR143-immunoreactive signals were detected in Lewy bodies and were colocalized with immunoreactive signals with anti-human Ser129 phosphorylated α-synuclein antibody. Although the significance of its occurrence in the inclusion bodies is unknown, our finding suggests possible implications of GPR143 in PD.
Collapse
Affiliation(s)
- Yoshio Goshima
- Department of Molecular Pharmacology & Neurobiology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
| | - Shuya Watanabe
- Department of Molecular Pharmacology & Neurobiology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
| | - Erika Seki
- Laboratory of Neuropathology, Tokyo Metropolitan Institute of Medical Sciences, Tokyo 156-8506, Japan.
| | - Motokazu Koga
- Department of Molecular Pharmacology & Neurobiology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan; Department of Anesthesiology, Graduate School of Medicine, Yokohama City University, Yokohama 236-0004, Japan.
| | - Daiki Masukawa
- Department of Molecular Pharmacology & Neurobiology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan.
| | - Fumio Nakamura
- Department of Molecular Pharmacology & Neurobiology, Yokohama City University Graduate School of Medicine, 3-9 Fukuura, Kanazawa-ku, Yokohama, 236-0004, Japan; Department of Biochemistry, School of Medicine, Tokyo Women's Medical University, Tokyo 162-8666, Japan.
| | - Takashi Komori
- Department of Laboratory Medicine and Pathology, Tokyo Metropolitan Neurological Hospital, Tokyo 183-0042, Japan
| | - Nobutaka Arai
- Laboratory of Neuropathology, Tokyo Metropolitan Institute of Medical Sciences, Tokyo 156-8506, Japan.
| |
Collapse
|
12
|
Silencing of PMEL attenuates melanization via activating lysosomes and degradation of tyrosinase by lysosomes. Biochem Biophys Res Commun 2018; 503:2536-2542. [PMID: 30208522 DOI: 10.1016/j.bbrc.2018.07.012] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 07/03/2018] [Indexed: 01/22/2023]
Abstract
The functionally specialized melanosome is a membrane-enclosed lysosome-related organelle, which coexists with lysosomes in melanocytes. Pre-melanosomal protein (PMEL) initiates pre-melanosome morphogenesis and is the only cell-specific pigment protein required for the formation of fibrils on which melanin is deposited in melanosomes. But the effects of PMEL on melanin synthesis and lysosome activity remain unclear. In the study, PMEL was silenced in human epidermal melanocytes by siRNA transfection. Compared to the non-treated group, melanin content in the transfected cells was greatly reduced. Real-time qPCR, Western blotting and immunofluorescence analyses all showed that PMEL-siRNA transfection reduced protein level of tyrosinase, a key enzyme in melanogenesis, but it does not affect tyrosinase gene expression. Moreover, in the absence of PMEL, lysosomal activation was manifested by an increase in the number of lysosomes and activity of hydrolysis enzymes. The lysosome inhibitors restored tyrosinase expression after PMEL silencing, indicating that tyrosinase was degradated by lysosomes. The data collectively showed that silencing of PMEL suppressed melanization through activating lysosomes and degradation of tyrosinase by lysosomes. Our findings provide novel insight into the interaction between the melanosome and its related organelle, the lysosome, supplying a new idea for the pathogenesis and clinical treatment of pigmented diseases.
Collapse
|
13
|
Juan T, Fürthauer M. Biogenesis and function of ESCRT-dependent extracellular vesicles. Semin Cell Dev Biol 2017; 74:66-77. [PMID: 28807885 DOI: 10.1016/j.semcdb.2017.08.022] [Citation(s) in RCA: 264] [Impact Index Per Article: 37.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 08/04/2017] [Accepted: 08/07/2017] [Indexed: 12/18/2022]
Abstract
From bacteria to humans, cells secrete a large variety of membrane-bound extracellular vesicles. Only relatively recently has it however started to become clear that the exovesicular transport of proteins and RNAs is important for normal physiology and numerous pathological conditions. Extracellular vesicles can be formed through the release of the intralumenal vesicles of multivesicular endosomes as so-called exosomes, or through direct, ectosomal, budding from the cell surface. Through their ability to promote the bending of membranes away from the cytoplasm, the components of the Endosomal Sorting Complex Required for Transport (ESCRT) have been implicated in both exo- and ectosomal biogenesis. Studies of the ESCRT machinery may therefore provide important insights into the formation and function of extracellular vesicles. In the present review, we first describe the cell biological mechanisms through which ESCRT components contribute to the biogenesis of different types of extracellular vesicles. We then discuss how recent functional studies have started to uncover important roles of ESCRT-dependent extracellular vesicles in a wide variety of processes, including the transport of developmental signaling molecules and embryonic morphogenesis, the regulation of social behavior and host-pathogen interactions, as well as the etiology and progression of neurodegenerative pathologies and cancer.
Collapse
Affiliation(s)
- Thomas Juan
- Université Côte d'Azur, CNRS, Inserm, iBV, France
| | | |
Collapse
|
14
|
De Filippo E, Manga P, Schiedel AC. Identification of Novel G Protein-Coupled Receptor 143 Ligands as Pharmacologic Tools for Investigating X-Linked Ocular Albinism. Invest Ophthalmol Vis Sci 2017. [PMID: 28632878 PMCID: PMC5482243 DOI: 10.1167/iovs.16-21128] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Purpose GPR143 regulates melanosome biogenesis and organelle size in pigment cells. The mechanisms underlying receptor function remain unclear. G protein–coupled receptors (GPCRs) are excellent pharmacologic targets; thus, we developed and applied a screening approach to identify potential GPR143 ligands and chemical modulators. Methods GPR143 interacts with β-arrestin; we therefore established a β-arrestin recruitment assay to screen for compounds that modulate activity. Because GPR143 is localized intracellularly, screening with the wild-type receptor would be restricted to agents absorbed by the cell. For the screen we used a mutant receptor, which shows similar basal activity as the wild type but traffics to the plasma membrane. We tested two compound libraries and investigated validated hits for their effects on melanocyte pigmentation. Results GPR143, which showed high constitutive activity in the β-arrestin assay, was inhibited by several compounds. The three validated inhibitors (pimozide, niclosamide, and ethacridine lactate) were assessed for impact on melanocytes. Pigmentation and expression of tyrosinase, a key melanogenic enzyme, were reduced by all compounds. Because GPR143 appears to be constitutively active, these compounds may turn off its activity. Conclusions X-linked ocular albinism type I, characterized by developmental eye defects, results from GPR143 mutations. Identifying pharmacologic agents that modulate GPR143 activity will contribute significantly to our understanding of its function and provide novel tools with which to study GPCRs in melanocytes and retinal pigment epithelium. Pimozide, one of three GPR143 inhibitors identified in this study, maybe be a good lead structure for development of more potent compounds and provide a platform for design of novel therapeutic agents.
Collapse
Affiliation(s)
| | - Prashiela Manga
- Ronald O. Perelman Department of Dermatology and Department of Cell Biology, New York University School of Medicine, New York, New York, United States
| | - Anke C Schiedel
- Pharmaceutical Chemistry I, PharmaCenter Bonn, University of Bonn, Bonn, Germany
| |
Collapse
|
15
|
De Filippo E, Schiedel AC, Manga P. Interaction between G Protein-Coupled Receptor 143 and Tyrosinase: Implications for Understanding Ocular Albinism Type 1. J Invest Dermatol 2016; 137:457-465. [PMID: 27720922 DOI: 10.1016/j.jid.2016.09.022] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2016] [Revised: 09/26/2016] [Accepted: 09/27/2016] [Indexed: 12/31/2022]
Abstract
Developmental eye defects in X-linked ocular albinism type 1 are caused by G-protein coupled receptor 143 (GPR143) mutations. Mutations result in dysfunctional melanosome biogenesis and macromelanosome formation in pigment cells, including melanocytes and retinal pigment epithelium. GPR143, primarily expressed in pigment cells, localizes exclusively to endolysosomal and melanosomal membranes unlike most G protein-coupled receptors, which localize to the plasma membrane. There is some debate regarding GPR143 function and elucidating the role of this receptor may be instrumental for understanding neurogenesis during eye development and for devising therapies for ocular albinism type I. Many G protein-coupled receptors require association with other proteins to function. These G protein-coupled receptor-interacting proteins also facilitate fine-tuning of receptor activity and tissue specificity. We therefore investigated potential GPR143 interaction partners, with a focus on the melanogenic enzyme tyrosinase. GPR143 coimmunoprecipitated with tyrosinase, while confocal microscopy demonstrated colocalization of the proteins. Furthermore, tyrosinase localized to the plasma membrane when coexpressed with a GPR143 trafficking mutant. The physical interaction between the proteins was confirmed using fluorescence resonance energy transfer. This interaction may be required in order for GPR143 to function as a monitor of melanosome maturation. Identifying tyrosinase as a potential GPR143 binding protein opens new avenues for investigating the mechanisms that regulate pigmentation and neurogenesis.
Collapse
Affiliation(s)
| | - Anke C Schiedel
- Pharmaceutical Chemistry I, PharmaCenter Bonn, University of Bonn, Bonn, Germany.
| | - Prashiela Manga
- Ronald O. Perelman, Department of Dermatology, New York University School of Medicine, New York, New York, USA.
| |
Collapse
|
16
|
Ocular Albinism Type 1 Regulates Melanogenesis in Mouse Melanocytes. Int J Mol Sci 2016; 17:ijms17101596. [PMID: 27690000 PMCID: PMC5085629 DOI: 10.3390/ijms17101596] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2016] [Revised: 09/07/2016] [Accepted: 09/13/2016] [Indexed: 12/22/2022] Open
Abstract
To investigate whether ocular albinism type 1 (OA1) is differentially expressed in the skin of mice with different coat colors and to determine its correlation with coat color establishment in mouse, the expression patterns and tissue distribution characterization of OA1 in the skin of mice with different coat colors were qualitatively and quantitatively analyzed by real-time quantitative PCR (qRT-PCR), immunofluorescence staining and Western blot. The qRT-PCR analysis revealed that OA1 mRNA was expressed in all mice skin samples tested, with the highest expression level in brown skin, a moderate expression level in black skin and the lowest expression level in gray skin. Positive OA1 protein bands were also detected in all skin samples by Western blot analysis. The relative expression levels of OA1 protein in both black and brown skin were significantly higher than that in gray skin, but there was no significant difference between black and brown mice. Immunofluorescence assays revealed that OA1 was mainly expressed in the hair follicle matrix, the inner and outer root sheath in the skin tissues with different coat colors. To get further insight into the important role of OA1 in the melanocytes’ pigmentation, we transfected the OA1 into mouse melanocytes and then detected the relative expression levels of pigmentation-related gene. Simultaneously, we tested the melanin content of melanocytes. As a result, the overexpression of OA1 significantly increased the expression levels of microphthalmia-associated transcription factor (MITF), tyrosinase (TYR), tyrosinase-related protein 1 (TRP1) and premelanosome protein (PMEL). However, the tyrosinase-related protein 2 (TRP2) level was attenuated. By contrast, the level of glycoprotein non-metastatic melanoma protein b (GPNMB) was unaffected by OA1 overexpression. Furthermore, we observed a significant increase in melanin content in mouse melanocyte transfected OA1. Therefore, we propose that OA1 may participate in the formation of coat color by regulating the level of MITF and the number, size, motility and maturation of melanosome.
Collapse
|
17
|
Jong YJI, O'Malley KL. Mechanisms Associated with Activation of Intracellular Metabotropic Glutamate Receptor, mGluR5. Neurochem Res 2016; 42:166-172. [PMID: 27514643 PMCID: PMC5283513 DOI: 10.1007/s11064-016-2026-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/18/2016] [Accepted: 07/29/2016] [Indexed: 12/28/2022]
Abstract
The group 1 metabotropic glutamate receptor, mGluR5, is found on the cell surface as well as on intracellular membranes where it can mediate both overlapping and unique signaling effects. Previously we have shown that glutamate activates intracellular mGluR5 by entry through sodium-dependent transporters and/or cystine glutamate exchangers. Calibrated antibody labelling suggests that the glutamate concentration within neurons is quite high (~10 mM) raising the question as to whether intracellular mGluR5 is maximally activated at all times or whether a different ligand might be responsible for receptor activation. To address this issue, we used cellular, optical and molecular techniques to show that intracellular glutamate is largely sequestered in mitochondria; that the glutamate concentration necessary to activate intracellular mGluR5 is about ten-fold higher than what is necessary to activate cell surface mGluR5; and uncaging caged glutamate within neurons can directly activate the receptor. Thus these studies further the concept that glutamate itself serves as the ligand for intracellular mGluR5.
Collapse
Affiliation(s)
- Yuh-Jiin I Jong
- Department of Neuroscience, Washington University School of Medicine, 660 South Euclid Ave, Saint Louis, MO, 63110, USA
| | - Karen L O'Malley
- Department of Neuroscience, Washington University School of Medicine, 660 South Euclid Ave, Saint Louis, MO, 63110, USA.
| |
Collapse
|
18
|
Tomas A, Vaughan SO, Burgoyne T, Sorkin A, Hartley JA, Hochhauser D, Futter CE. WASH and Tsg101/ALIX-dependent diversion of stress-internalized EGFR from the canonical endocytic pathway. Nat Commun 2015; 6:7324. [PMID: 26066081 PMCID: PMC4490399 DOI: 10.1038/ncomms8324] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 04/27/2015] [Indexed: 12/14/2022] Open
Abstract
Stress exposure triggers ligand-independent EGF receptor (EGFR) endocytosis, but its post-endocytic fate and role in regulating signalling are unclear. We show that the p38 MAP kinase-dependent, EGFR tyrosine kinase (TK)-independent EGFR internalization induced by ultraviolet light C (UVC) or the cancer therapeutic cisplatin, is followed by diversion from the canonical endocytic pathway. Instead of lysosomal degradation or plasma membrane recycling, EGFR accumulates in a subset of LBPA-rich perinuclear multivesicular bodies (MVBs) distinct from those carrying EGF-stimulated EGFR. Stress-internalized EGFR co-segregates with exogenously expressed pre-melanosomal markers OA1 and fibrillar PMEL, following early endosomal sorting by the actin polymerization-promoting WASH complex. Stress-internalized EGFR is retained intracellularly by continued p38 activity in a mechanism involving ubiquitin-independent, ESCRT/ALIX-dependent incorporation onto intraluminal vesicles (ILVs) of MVBs. In contrast to the internalization-independent EGF-stimulated activation, UVC/cisplatin-triggered EGFR activation depends on EGFR internalization and intracellular retention. EGFR signalling from this MVB subpopulation delays apoptosis and might contribute to chemoresistance.
Collapse
Affiliation(s)
- Alejandra Tomas
- Department of Cell Biology, UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
- Present address: Section of Cell Biology, Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, Imperial College London, Hammersmith Campus, Du Cane Road, London W12 0NN, UK
| | - Simon O. Vaughan
- Department of Cell Biology, UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Thomas Burgoyne
- Department of Cell Biology, UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| | - Alexander Sorkin
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania 15261, USA
| | - John A. Hartley
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, Paul O'Gorman Building, University College London, 72 Huntley Street, London WC1E 6BT, UK
| | - Daniel Hochhauser
- Cancer Research UK Drug-DNA Interactions Research Group, UCL Cancer Institute, Paul O'Gorman Building, University College London, 72 Huntley Street, London WC1E 6BT, UK
| | - Clare E. Futter
- Department of Cell Biology, UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London EC1V 9EL, UK
| |
Collapse
|
19
|
Lysosomal storage disease in the brain: mutations of the β-mannosidase gene identified in autosomal dominant nystagmus. Genet Med 2015; 17:971-9. [PMID: 25741867 DOI: 10.1038/gim.2015.10] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 01/12/2015] [Indexed: 11/08/2022] Open
Abstract
PURPOSE Genetic etiology of congenital/infantile nystagmus remains largely unknown. This study aimed to identify genomic mutations in patients with infantile nystagmus and an associated disease network. METHODS Patients with inherited and sporadic infantile nystagmus were recruited for whole-exome and Sanger sequencing. β-Mannosidase activities were measured. Gene expression, protein-protein interaction, and nystagmus-associated lysosomal storage disease (LSD) genes were analyzed. RESULTS A novel heterozygous mutation (c.2013G>A; p.R638H) of MANBA, which encodes lysosomal β-mannosidase, was identified in patients with autosomal-dominant nystagmus. An additional mutation (c.2346T>A; p.L749H) in MANBA was found by screening patients with sporadic nystagmus. MANBA was expressed in the pretectal nucleus of the developing midbrain, known to be involved in oculomotor and optokinetic nystagmus. Functional validation of these mutations demonstrated a significant decrease of β-mannosidase activities in the patients as well as in mutant-transfected HEK293T cells. Further analysis revealed that nystagmus is present in at least 24 different LSDs involving the brain. CONCLUSION This is the first identification of MANBA mutations in patients with autosomal-dominant nystagmus, suggesting a new clinical entity. Because β-mannosidase activities are required for development of the oculomotor nervous system, our findings shed new light on the role of LSD-associated genes in the pathogenesis of infantile nystagmus.
Collapse
|
20
|
Kilpatrick BS, Eden ER, Hockey LN, Futter CE, Patel S. Methods for monitoring lysosomal morphology. Methods Cell Biol 2015; 126:1-19. [PMID: 25665438 DOI: 10.1016/bs.mcb.2014.10.018] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Lysosomes are abundant organelles best known for their crucial role in macromolecule turnover. Lysosome dysfunction features in several diseases exemplified by the lysosomal storage disorders and is often associated with marked changes in lysosome structure. Lysosomal morphology may therefore serve as a sensitive readout of endocytic well-being. Here we describe methods for monitoring lysosome morphology in fixed and live cells using fluorescent probes and electron microscopy.
Collapse
Affiliation(s)
- Bethan S Kilpatrick
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Emily R Eden
- Department of Cell Biology, Institute of Ophthalmology, University College London, London, UK
| | - Leanne N Hockey
- Department of Cell and Developmental Biology, University College London, London, UK
| | - Clare E Futter
- Department of Cell Biology, Institute of Ophthalmology, University College London, London, UK
| | - Sandip Patel
- Department of Cell and Developmental Biology, University College London, London, UK
| |
Collapse
|
21
|
Jong YJI, Sergin I, Purgert CA, O'Malley KL. Location-dependent signaling of the group 1 metabotropic glutamate receptor mGlu5. Mol Pharmacol 2014; 86:774-85. [PMID: 25326002 DOI: 10.1124/mol.114.094763] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Although G protein-coupled receptors are primarily known for converting extracellular signals into intracellular responses, some receptors, such as the group 1 metabotropic glutamate receptor, mGlu5, are also localized on intracellular membranes where they can mediate both overlapping and unique signaling effects. Thus, besides "ligand bias," whereby a receptor's signaling modality can shift from G protein dependence to independence, canonical mGlu5 receptor signaling can also be influenced by "location bias" (i.e., the particular membrane and/or cell type from which it signals). Because mGlu5 receptors play important roles in both normal development and in disorders such as Fragile X syndrome, autism, epilepsy, addiction, anxiety, schizophrenia, pain, dyskinesias, and melanoma, a large number of drugs are being developed to allosterically target this receptor. Therefore, it is critical to understand how such drugs might be affecting mGlu5 receptor function on different membranes and in different brain regions. Further elucidation of the site(s) of action of these drugs may determine which signal pathways mediate therapeutic efficacy.
Collapse
Affiliation(s)
- Yuh-Jiin I Jong
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri
| | - Ismail Sergin
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri
| | - Carolyn A Purgert
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri
| | - Karen L O'Malley
- Department of Anatomy and Neurobiology, Washington University School of Medicine, St. Louis, Missouri
| |
Collapse
|
22
|
The vacuolar-sorting protein Snf7 is required for export of virulence determinants in members of the Cryptococcus neoformans complex. Sci Rep 2014; 4:6198. [PMID: 25178636 PMCID: PMC4151102 DOI: 10.1038/srep06198] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 08/04/2014] [Indexed: 02/06/2023] Open
Abstract
Fungal pathogenesis requires a number of extracellularly released virulence factors. Recent studies demonstrating that most fungal extracellular molecules lack secretory tags suggest that unconventional secretion mechanisms and fungal virulence are strictly connected. Proteins of the endosomal sorting complex required for transport (ESCRT) have been recently associated with polysaccharide export in the yeast-like human pathogen Cryptococcus neoformans. Snf7 is a key ESCRT operator required for unconventional secretion in Eukaryotes. In this study we generated snf7Δ mutant strains of C. neoformans and its sibling species C. gattii. Lack of Snf7 resulted in important alterations in polysaccharide secretion, capsular formation and pigmentation. This phenotype culminated with loss of virulence in an intranasal model of murine infection in both species. Our data support the notion that Snf7 expression regulates virulence in C. neoformans and C. gattii by ablating polysaccharide and melanin traffic. These results are in agreement with the observation that unconventional secretion is essential for cryptococcal pathogenesis and strongly suggest the occurrence of still obscure mechanisms of exportation of non-protein molecules in Eukaryotes.
Collapse
|