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Luo Z, Zhang X, Fleig A, Romo D, Hull KG, Horgen FD, Sun HS, Feng ZP. TRPM7 in neurodevelopment and therapeutic prospects for neurodegenerative disease. Cell Calcium 2024; 120:102886. [PMID: 38631163 DOI: 10.1016/j.ceca.2024.102886] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2023] [Revised: 04/02/2024] [Accepted: 04/05/2024] [Indexed: 04/19/2024]
Abstract
Neurodevelopment, a complex and highly regulated process, plays a foundational role in shaping the structure and function of the nervous system. The transient receptor potential melastatin 7 (TRPM7), a divalent cation channel with an α-kinase domain, mediates a wide range of cellular functions, including proliferation, migration, cell adhesion, and survival, all of which are essential processes in neurodevelopment. The global knockout of either TRPM7 or TRPM7-kinase is embryonically lethal, highlighting the crucial role of TRPM7 in development in vivo. Subsequent research further revealed that TRPM7 is indeed involved in various key processes throughout neurodevelopment, from maintaining pluripotency during embryogenesis to regulating gastrulation, neural tube closure, axonal outgrowth, synaptic density, and learning and memory. Moreover, a discrepancy in TRPM7 expression and/or function has been associated with neuropathological conditions, including ischemic stroke, Alzheimer's disease, and Parkinson's disease. Understanding the mechanisms of proper neurodevelopment may provide us with the knowledge required to develop therapeutic interventions that can overcome the challenges of regeneration in CNS injuries and neurodegenerative diseases. Considering that ion channels are the third-largest class targeted for drug development, TRPM7's dual roles in development and degeneration emphasize its therapeutic potential. This review provides a comprehensive overview of the current literature on TRPM7 in various aspects of neurodevelopment. It also discusses the links between neurodevelopment and neurodegeneration, and highlights TRPM7 as a potential therapeutic target for neurodegenerative disorders, with a focus on repair and regeneration.
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Affiliation(s)
- Zhengwei Luo
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada; Department of Surgery, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Xinyang Zhang
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada; Department of Surgery, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada
| | - Andrea Fleig
- Center for Biomedical Research at The Queen's Medical Center and John A. Burns School of Medicine and Cancer Center at the University of Hawaii, Honolulu, HI, 96720, USA
| | - Daniel Romo
- Department of Chemistry & Biochemistry, Baylor University, Waco, TX 76798-7348, USA; The CPRIT Synthesis and Drug-Lead Discovery Laboratory, Baylor University, Waco, TX 76798, USA
| | - Kenneth G Hull
- Department of Chemistry & Biochemistry, Baylor University, Waco, TX 76798-7348, USA
| | - F David Horgen
- Department of Natural Sciences, Hawaii Pacific University, Kaneohe, HI, 96744, USA
| | - Hong-Shuo Sun
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada; Department of Surgery, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada; Department of Pharmacology, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada; Leslie Dan Faculty of Pharmacy, University of Toronto, 144 College Street, Toronto, Ontario, M5S 3M2, Canada.
| | - Zhong-Ping Feng
- Department of Physiology, Temerty Faculty of Medicine, University of Toronto, 1 King's College Circle, Toronto, Ontario, M5S 1A8, Canada.
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Hue I, Capilla E, Rosell-Moll E, Balbuena-Pecino S, Goffette V, Gabillard JC, Navarro I. Recent advances in the crosstalk between adipose, muscle and bone tissues in fish. Front Endocrinol (Lausanne) 2023; 14:1155202. [PMID: 36998471 PMCID: PMC10043431 DOI: 10.3389/fendo.2023.1155202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 02/27/2023] [Indexed: 03/17/2023] Open
Abstract
Control of tissue metabolism and growth involves interactions between organs, tissues, and cell types, mediated by cytokines or direct communication through cellular exchanges. Indeed, over the past decades, many peptides produced by adipose tissue, skeletal muscle and bone named adipokines, myokines and osteokines respectively, have been identified in mammals playing key roles in organ/tissue development and function. Some of them are released into the circulation acting as classical hormones, but they can also act locally showing autocrine/paracrine effects. In recent years, some of these cytokines have been identified in fish models of biomedical or agronomic interest. In this review, we will present their state of the art focusing on local actions and inter-tissue effects. Adipokines reported in fish adipocytes include adiponectin and leptin among others. We will focus on their structure characteristics, gene expression, receptors, and effects, in the adipose tissue itself, mainly regulating cell differentiation and metabolism, but in muscle and bone as target tissues too. Moreover, lipid metabolites, named lipokines, can also act as signaling molecules regulating metabolic homeostasis. Regarding myokines, the best documented in fish are myostatin and the insulin-like growth factors. This review summarizes their characteristics at a molecular level, and describes both, autocrine effects and interactions with adipose tissue and bone. Nonetheless, our understanding of the functions and mechanisms of action of many of these cytokines is still largely incomplete in fish, especially concerning osteokines (i.e., osteocalcin), whose potential cross talking roles remain to be elucidated. Furthermore, by using selective breeding or genetic tools, the formation of a specific tissue can be altered, highlighting the consequences on other tissues, and allowing the identification of communication signals. The specific effects of identified cytokines validated through in vitro models or in vivo trials will be described. Moreover, future scientific fronts (i.e., exosomes) and tools (i.e., co-cultures, organoids) for a better understanding of inter-organ crosstalk in fish will also be presented. As a final consideration, further identification of molecules involved in inter-tissue communication will open new avenues of knowledge in the control of fish homeostasis, as well as possible strategies to be applied in aquaculture or biomedicine.
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Affiliation(s)
- Isabelle Hue
- Laboratory of Fish Physiology and Genomics, UR1037, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Rennes, France
| | - Encarnación Capilla
- Departament de Biologia Cel·lular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Enrique Rosell-Moll
- Departament de Biologia Cel·lular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Sara Balbuena-Pecino
- Departament de Biologia Cel·lular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
| | - Valentine Goffette
- Laboratory of Fish Physiology and Genomics, UR1037, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Rennes, France
| | - Jean-Charles Gabillard
- Laboratory of Fish Physiology and Genomics, UR1037, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement (INRAE), Rennes, France
| | - Isabel Navarro
- Departament de Biologia Cel·lular, Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain
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Vargas-Poussou R, Claverie-Martin F, Prot-Bertoye C, Carotti V, van der Wijst J, Perdomo-Ramirez A, Fraga-Rodriguez GM, Hureaux M, Bos C, Latta F, Houillier P, Hoenderop JGJ, de Baaij JHF. Possible role for rare TRPM7 variants in patients with hypomagnesaemia with secondary hypocalcaemia. Nephrol Dial Transplant 2022; 38:679-690. [PMID: 35561741 PMCID: PMC9976740 DOI: 10.1093/ndt/gfac182] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Hypomagnesaemia with secondary hypocal-caemia (HSH) is a rare autosomal recessive disorder caused by pathogenic variants in TRPM6, encoding the channel-kinase transient receptor potential melastatin type 6. Patients have very low serum magnesium (Mg2+) levels and suffer from muscle cramps and seizures. Despite genetic testing, a subgroup of HSH patients remains without a diagnosis. METHODS In this study, two families with an HSH phenotype but negative for TRPM6 pathogenic variants were subjected to whole exome sequencing. Using a complementary combination of biochemical and functional analyses in overexpression systems and patient-derived fibroblasts, the effect of the TRPM7-identified variants on Mg2+ transport was examined. RESULTS For the first time, variants in TRPM7 were identified in two families as a potential cause for hereditary HSH. Patients suffer from seizures and muscle cramps due to magnesium deficiency and episodes of hypocalcaemia. In the first family, a splice site variant caused the incorporation of intron 1 sequences into the TRPM7 messenger RNA and generated a premature stop codon. As a consequence, patient-derived fibroblasts exhibit decreased cell growth. In the second family, a heterozygous missense variant in the pore domain resulted in decreased TRPM7 channel activity. CONCLUSIONS We establish TRPM7 as a prime candidate gene for autosomal dominant hypomagnesaemia and secondary hypocalcaemia. Screening of unresolved patients with hypocalcaemia and secondary hypocalcaemia may further establish TRPM7 pathogenic variants as a novel Mendelian disorder.
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Affiliation(s)
| | | | | | - Valentina Carotti
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jenny van der Wijst
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Ana Perdomo-Ramirez
- Unidad de Investigación, Renal Tube Group, Hospital Universitario Nuestra Señora de Candelaria, Santa Cruz de Tenerife, Spain
| | | | - Marguerite Hureaux
- Département de Génétique, Centre de référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Hôpital Européen Georges Pompidou, Paris, France
| | - Caro Bos
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Femke Latta
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Pascal Houillier
- Centre de Recherche des Cordeliers, Sorbonne Université, INSERM, Université de Paris, CNRS, Paris, France,Department of Physiology, Assistance Publique-Hôpitaux de Paris, Hôpital Européen Georges Pompidou, Paris, France,Centre de Référence des Maladies Rénales Héréditaires de l'Enfant et de l'Adulte, Paris, France
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
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Hansen NGW, Madsen SS, Brauckhoff M, Heuer RM, Schlenker LS, Engelund MB, Grosell M. Magnesium transport in the aglomerular kidney of the Gulf toadfish (Opsanus beta). J Comp Physiol B 2021; 191:865-880. [PMID: 34302186 DOI: 10.1007/s00360-021-01392-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 05/04/2021] [Accepted: 07/06/2021] [Indexed: 11/30/2022]
Abstract
Despite having an aglomerular kidney, Gulf toadfish can survive in water ranging from nearly fresh up to 70 parts per thousand salinity. In hyperosmotic environments, the major renal function is to balance the passive Mg2+ load from the environment with an equal excretion. However, the molecular transporters involved in Mg2+ secretion are poorly understood. We investigated whether environmental MgCl2 alone or in combination with elevated salinity affected transcriptional regulation of genes classically involved in renal Mg2+ secretion (slc41a1, slc41a3, cnnm3) together with three novel genes (trpm6, trpm7, claudin-19) and two isoforms of the Na+/K+-ATPase α-subunit (nka-α1a, nka-α1b). First, toadfish were acclimated to 5, 9, 35, or 60 ppt water (corresponding to ~ 7, 13, 50 and 108 mmol L-1 ambient [Mg2+], respectively) and sampled at 24 h or 9 days. Next, the impact of elevated ambient [Mg2+] was explored by exposing toadfish to control (50 mmol L-1 Mg2+), or elevated [Mg2+] (100 mmol L-1) at a constant salinity for 7 days. Mg2+ levels in this experiment corresponded with levels in control and hypersaline conditions in the first experiment. A salinity increase from 5 to 60 ppt stimulated the level of all investigated transcripts in the kidney. In Mg2+-exposed fish, we observed a 14-fold increase in the volume of intestinal fluids and elevated plasma osmolality and [Mg2+], suggesting osmoregulatory challenges. However, none of the renal gene targets changed expression compared with the control group. We conclude that transcriptional regulation of renal Mg2+ transporters is induced by elevated [Mg2+] in combination with salinity rather than elevated ambient [Mg2+] alone.
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Affiliation(s)
- Nina G Walker Hansen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Steffen S Madsen
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark.
| | - Melanie Brauckhoff
- Department of Biology, University of Southern Denmark, Campusvej 55, 5230, Odense M, Denmark
| | - Rachael M Heuer
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
| | - Lela S Schlenker
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
| | - Morten B Engelund
- Department of Clinical Genetics, Odense University Hospital, 5000, Odense M, Denmark
| | - Martin Grosell
- Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL, USA
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Bi X, Zhang Q, Zhuang F, Lu W, Wang Y, Ding F. An Observational Cohort Study of the 2-Month Use of Regional Citrate Anticoagulation in Maintenance Hemodialysis Patients with Cerebral Hemorrhage. Med Sci Monit 2021; 27:e930513. [PMID: 33859156 PMCID: PMC8056873 DOI: 10.12659/msm.930513] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Background Regional citrate anticoagulation (RCA) is a recommended anticoagulation alternative for patients at high risk of bleeding while undergoing intermittent hemodialysis. Previous reports implied the risk of citrate application on bone metabolism. It is unclear whether long-term use of RCA is safe for maintenance hemodialysis patients in terms of bone metabolism. Material/Methods Seven patients with cerebral hemorrhage were included in the study. Blood samples were collected at baseline and 4 and 8 weeks after treatment. Spent dialysate samples were collected during each mid-week dialysis session, using the partial dialysate collection method. All patients were treated with RCA for 4 to 8 weeks, according to their clinical condition. We assessed bone metabolism-associated parameters, bone turnover markers, and magnesium loss at each dialysis session. Results Serum magnesium levels were 1.24±0.13 mmol/L at baseline and significantly decreased to 1.16±0.14 mmol/L after 4 weeks of RCA treatment (P=0.025). Most patients had negative magnesium balance during citrate hemodialysis. Serum total calcium levels did not change significantly after treatment. One bone marker, N-terminal propeptide of type I procollagen (PINP), significantly decreased from 146.07±130.12 mmol/L to 92.42±79.01 mmol/L after citrate treatment (P=0.018). No significant changes were detected in other bone turnover markers. Conclusions Relatively long-term RCA treatment may decrease serum magnesium levels due to negative magnesium balance. Bone formation marker PINP seemed to decrease after treatment, while other bone turnover markers did not change significantly. Further investigation is needed to verify the effect of RCA on bone remodeling.
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Affiliation(s)
- Xiao Bi
- Division of Nephrology and Critical Care Nephrology Unit, Shanghai Ninth People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai, China (mainland)
| | - Qi Zhang
- Division of Nephrology and Critical Care Nephrology Unit, Shanghai Ninth People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai, China (mainland)
| | - Feng Zhuang
- Division of Nephrology and Critical Care Nephrology Unit, Shanghai Ninth People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai, China (mainland)
| | - Wei Lu
- Division of Nephrology and Critical Care Nephrology Unit, Shanghai Ninth People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai, China (mainland)
| | - Yingdeng Wang
- Division of Nephrology and Critical Care Nephrology Unit, Shanghai Ninth People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai, China (mainland)
| | - Feng Ding
- Division of Nephrology and Critical Care Nephrology Unit, Shanghai Ninth People's Hospital, Shanghai JiaoTong University, School of Medicine, Shanghai, China (mainland)
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6
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Li S, Liu C, Goldstein A, Xin Y, Ke C, Duan C. Calcium State-Dependent Regulation of Epithelial Cell Quiescence by Stanniocalcin 1a. Front Cell Dev Biol 2021; 9:662915. [PMID: 33898465 PMCID: PMC8063699 DOI: 10.3389/fcell.2021.662915] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Accepted: 03/08/2021] [Indexed: 11/15/2022] Open
Abstract
The molecular mechanisms regulating cell quiescence-proliferation balance are not well defined. Using a zebrafish model, we report that Stc1a, a secreted glycoprotein, plays a key role in regulating the quiescence-proliferation balance of Ca2+ transporting epithelial cells (ionocytes). Zebrafish stc1a, but not the other stc genes, is expressed in a Ca2+ state-dependent manner. Genetic deletion of stc1a, but not stc2b, increased ionocyte proliferation, leading to elevated body Ca2+ levels, cardiac edema, body swelling, and premature death. The increased ionocyte proliferation was accompanied by an increase in the IGF1 receptor-mediated PI3 kinase-Akt-Tor signaling activity in ionocytes. Inhibition of the IGF1 receptor, PI3 kinase, Akt, and Tor signaling reduced ionocyte proliferation and rescued the edema and premature death in stc1a–/– fish, suggesting that Stc1a promotes ionocyte quiescence by suppressing local IGF signaling activity. Mechanistically, Stc1 acts by inhibiting Papp-aa, a zinc metalloproteinase degrading Igfbp5a. Inhibition of Papp-aa proteinase activity restored ionocyte quiescence-proliferation balance. Genetic deletion of papp-aa or its substrate igfbp5a in the stc1a–/– background reduced ionocyte proliferation and rescued the edema and premature death. These findings uncover a novel and Ca2+ state-dependent pathway regulating cell quiescence. Our findings also provide new insights into the importance of ionocyte quiescent-proliferation balance in organismal Ca2+ homeostasis and survival.
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Affiliation(s)
- Shuang Li
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China.,College of Ocean and Earth Sciences, Xiamen University, Xiamen, China.,Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Chengdong Liu
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Allison Goldstein
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Yi Xin
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
| | - Caihuan Ke
- State Key Laboratory of Marine Environmental Science, Xiamen University, Xiamen, China.,College of Ocean and Earth Sciences, Xiamen University, Xiamen, China
| | - Cunming Duan
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI, United States
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Singh AP, Sosa MX, Fang J, Shanmukhappa SK, Hubaud A, Fawcett CH, Molind GJ, Tsai T, Capodieci P, Wetzel K, Sanchez E, Wang G, Coble M, Tang W, Cadena SM, Fishman MC, Glass DJ. αKlotho Regulates Age-Associated Vascular Calcification and Lifespan in Zebrafish. Cell Rep 2019; 28:2767-2776.e5. [DOI: 10.1016/j.celrep.2019.08.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 07/02/2019] [Accepted: 07/31/2019] [Indexed: 10/26/2022] Open
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Arjona FJ, Latta F, Mohammed SG, Thomassen M, van Wijk E, Bindels RJM, Hoenderop JGJ, de Baaij JHF. SLC41A1 is essential for magnesium homeostasis in vivo. Pflugers Arch 2019; 471:845-860. [PMID: 30417250 PMCID: PMC6533229 DOI: 10.1007/s00424-018-2234-9] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 11/01/2018] [Accepted: 11/04/2018] [Indexed: 01/19/2023]
Abstract
Solute carrier family 41 member A1 (SLC41A1) has been suggested to mediate magnesium (Mg2+) transport by several in vitro studies. However, the physiological function of SLC41A1 remains to be elucidated. In this study, cellular Mg2+ transport assays combined with zebrafish slc41a1 knockdown experiments were performed to disclose SLC41A1 function and its physiological relevance. The gene slc41a1 is ubiquitously expressed in zebrafish tissues and is regulated by water and dietary Mg2+ availability. Knockdown of slc41a1 in zebrafish larvae grown in a Mg2+-free medium resulted in a unique phenotype characterized by a decrease in zebrafish Mg content. This decrease shows that SLC41A1 is required to maintain Mg2+ balance and its dysfunction results in renal Mg2+ wasting in zebrafish larvae. Importantly, the Mg content of the larvae is rescued when mouse SLC41A1 is expressed in slc41a1-knockdown zebrafish. Conversely, expression of mammalian SLC41A1-p.Asp262Ala, harboring a mutation in the ion-conducting SLC41A1 pore, did not reverse the renal Mg2+ wasting. 25Mg2+ transport assays in human embryonic kidney 293 (HEK293) cells overexpressing SLC41A1 demonstrated that SLC41A1 mediates cellular Mg2+ extrusion independently of sodium (Na+). In contrast, SLC41A1-p.Asp262Ala expressing HEK293 cells displayed similar Mg2+ extrusion activities than control (mock) cells. In polarized Madin-Darby canine kidney cells, SLC41A1 localized to the basolateral cell membrane. Our results demonstrate that SLC41A1 facilitates renal Mg2+ reabsorption in the zebrafish model. Furthermore, our data suggest that SLC41A1 mediates both Mg2+ uptake and extrusion.
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Affiliation(s)
- Francisco J Arjona
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Femke Latta
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Sami G Mohammed
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Michael Thomassen
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Erwin van Wijk
- Department of Otorhinolaryngology, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Center, Nijmegen, The Netherlands
| | - René J M Bindels
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Joost G J Hoenderop
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands
| | - Jeroen H F de Baaij
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
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Physical & mental activities enhance the neuroprotective effect of vinpocetine & coenzyme Q10 combination against Alzheimer & bone remodeling in rats. Life Sci 2019; 229:21-35. [PMID: 31063734 DOI: 10.1016/j.lfs.2019.05.006] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 04/22/2019] [Accepted: 05/03/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND Alzheimer's disease is a neurodegenerative disorder characterized by a progressive decline of cognitive abilities as well as bone loss. Physical and mental activities maintain cognitive functions as well as increase bone mass by inhibiting bone resorption. VIN and CoQ10 are neuroprotective drugs that possess anti-inflammatory and antioxidant properties. AIMS To study the effect of PH&M on enhancing the neuroprotective role of VIN and CoQ10 combination during induction of AD model in rats besides their role against bone mass loss associated with AD model. MAIN METHODS Six groups of rats were received saline, AlCl3, and PH&M daily either alone or with a combination of VIN and CoQ10 for 4 weeks. Various biochemical analyses were performed to evaluate the extent of brain damage such as ACHE, β-secretase, chitinase, Aβ, tau protein, and monoamines besides the inflammatory and antioxidant parameters. Serum levels of minerals as well as 25-OHD, PTH, RANKL, and OPG levels were measured to detect the extent of bone impairment. Also, histopathological changes were evaluated in different brain regions and hind paw. KEY FINDINGS VIN and CoQ10 combination together with PH&M significantly attenuated the neurodegeneration induced by AlCl3 administration through the improvement of AD markers in brain tissue as well as oxidant and inflammatory markers. Bone resorption markers, serum minerals, and PTH levels were also normalized too. SIGNIFICANCE Neuroprotective drugs together with PH&M have a more protective effect against AD and bone loss rather than PH&M alone.
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Verri T, Werner A. Type II Na +-phosphate Cotransporters and Phosphate Balance in Teleost Fish. Pflugers Arch 2018; 471:193-212. [PMID: 30542786 DOI: 10.1007/s00424-018-2239-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 11/15/2018] [Accepted: 11/18/2018] [Indexed: 12/27/2022]
Abstract
Teleost fish are excellent models to study the phylogeny of the slc34 gene family, Slc34-mediated phosphate (Pi) transport and how Slc34 transporters contribute Pi homeostasis. Fish need to accumulate Pi from the diet to sustain growth. Much alike in mammals, intestinal uptake in fish is partly a paracellular and partly a Slc34-mediated transcellular process. Acute regulation of Pi balance is achieved in the kidney via a combination of Slc34-mediated secretion and/or reabsorption. A great plasticity is observed in how various species perform and combine the different processes of secretion and reabsorption. A reason for this diversity is found in one or two whole genome duplication events followed by potential gene loss; consequently, teleosts exhibit distinctly different repertoires of Slc34 transporters. Moreover, due to habitats with vastly different salinity, teleosts face the challenge of either preserving water in a hyperosmotic environment (seawater) or excreting water in hypoosmotic freshwater. An additional challenge in understanding teleost Pi homeostasis are the genome duplication and retention events that diversified peptide hormones such as parathyroid hormone and stanniocalcin. Dietary Pi and non-coding RNAs also regulate the expression of piscine Slc34 transporters. The adaptive responses of teleost Slc34 transporters to e.g. Pi diets and vitamin D are informative in the context of comparative physiology, but also relevant in applied physiology and aquaculture. In fact, Pi is essential for teleost fish growth but it also exerts significant adverse consequences if over-supplied. Thus, investigating Slc34 transporters helps tuning the physiology of commercially valuable teleost fish in a confined environment.
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Affiliation(s)
- Tiziano Verri
- Laboratory of General Physiology, Department of Biological and Environmental Sciences and Technologies, University of Salento, Lecce, Italy.
| | - Andreas Werner
- Epithelial Research Group, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, UK.
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Cai N, Lou L, Al-Saadi N, Tetteh S, Runnels LW. The kinase activity of the channel-kinase protein TRPM7 regulates stability and localization of the TRPM7 channel in polarized epithelial cells. J Biol Chem 2018; 293:11491-11504. [PMID: 29866880 DOI: 10.1074/jbc.ra118.001925] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 05/25/2018] [Indexed: 12/13/2022] Open
Abstract
The channel-kinase transient receptor potential melastatin 7 (TRPM7) is a bifunctional protein with ion channel and kinase domains. The kinase activity of TRPM7 has been linked to the regulation of a broad range of cellular activities, but little is understood as to how the channel itself is regulated by its own kinase activity. Here, using several mammalian cell lines expressing WT TRPM7 or kinase-inactive variants, we discovered that compared with the cells expressing WT TRPM7, cells in which TRPM7's kinase activity was inactivated had faster degradation, elevated ubiquitination, and increased intracellular retention of the channel. Mutational analysis of TRPM7 autophosphorylation sites further revealed a role for Ser-1360 of TRPM7 as a key residue mediating both TRPM7 stability and intracellular trafficking. Additional trafficking roles were uncovered for Ser-1403 and Ser-1567, whose phosphorylation by TRPM7's kinase activity mediated the interaction of the channel with the signaling protein 14-3-3θ. In summary, our results point to a critical role for TRPM7's kinase activity in regulating proteasome-mediated turnover of the TRPM7 channel and controlling its cellular localization in polarized epithelial cells. Overall, these findings improve our understanding of the significance of TRPM7's kinase activity for functional regulation of its channel activity.
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Affiliation(s)
- Na Cai
- Department of Pharmacology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - Liping Lou
- Department of Pharmacology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - Namariq Al-Saadi
- Department of Pharmacology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854; University of Misan, Amarah 62001, Iraq
| | - Sandra Tetteh
- Department of Pharmacology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854
| | - Loren W Runnels
- Department of Pharmacology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey 08854.
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12
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13
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Lin CH, Hu HJ, Hwang PP. Molecular Physiology of the Hypocalcemic Action of Fibroblast Growth Factor 23 in Zebrafish (Danio rerio). Endocrinology 2017; 158:1347-1358. [PMID: 28323996 DOI: 10.1210/en.2016-1883] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 02/23/2017] [Indexed: 12/23/2022]
Abstract
Fibroblast growth factor 23 (FGF23), a hormone required for phosphorus metabolism, was recently proposed to act on Ca2+ uptake; however, the available evidence of how FGF23 controls the body fluid Ca2+ homeostasis needs to be further clarified. The use of zebrafish as a model system revealed that FGF23 is specifically expressed in the corpuscles of Stannius (CS), an organ involved in Ca2+ homeostasis in fish, and that its expression is stimulated by ambient water with a high Ca2+ level. The overexpression of FGF23 inhibited Ca2+ uptake by downregulating the messenger RNA (mRNA) expression of epithelium calcium channel. Calcium-sensing receptor (CaSR), which senses changes in extracellular Ca2+ levels and modulates calciotropic hormones in organs controlling Ca2+ homeostasis in vertebrates, was found to be coexpressed with FGF23 in the CS. In addition, upregulated expression of FGF23 mRNA was detected in morphants of stanniocalcin 1 (stc1, another hypocalcemic factor synthesized in the CS), and knockdown of CaSR suppressed such upregulation and enhanced Ca2+ uptake. Taken together, our data indicate that FGF23 functions as a hypocalcemic hormone in zebrafish and that the CaSR/STC1-FGF23 axis is involved in body fluid Ca2+ homeostasis in vertebrates.
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Affiliation(s)
- Chia-Hao Lin
- National Institute for Basic Biology, National Institutes of Natural Sciences, Okazaki, Aichi 444-8787, Japan
| | - Huei-Jyun Hu
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan, ROC
| | - Pung-Pung Hwang
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei 11529, Taiwan, ROC
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14
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Kersten S, Arjona FJ. Ion transport in the zebrafish kidney from a human disease angle: possibilities, considerations, and future perspectives. Am J Physiol Renal Physiol 2017; 312:F172-F189. [DOI: 10.1152/ajprenal.00425.2016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Revised: 11/11/2016] [Accepted: 11/14/2016] [Indexed: 12/31/2022] Open
Abstract
Unique experimental advantages, such as its embryonic/larval transparency, high-throughput nature, and ease of genetic modification, underpin the rapid emergence of the zebrafish ( Danio rerio) as a preeminent model in biomedical research. Particularly in the field of nephrology, the zebrafish provides a promising model for studying the physiological implications of human solute transport processes along consecutive nephron segments. However, although the zebrafish might be considered a valuable model for numerous renal ion transport diseases and functional studies of many channels and transporters, not all human renal electrolyte transport mechanisms and human diseases can be modeled in the zebrafish. With this review, we explore the ontogeny of zebrafish renal ion transport, its nephron structure and function, and thereby demonstrate the clinical translational value of this model. By critical assessment of genomic and amino acid conservation of human proteins involved in renal ion handling (channels, transporters, and claudins), kidney and nephron segment conservation, and renal electrolyte transport physiology in the zebrafish, we provide researchers and nephrologists with an indication of the possibilities and considerations of the zebrafish as a model for human renal ion transport. Combined with advanced techniques envisioned for the future, implementation of the zebrafish might expand beyond unraveling pathophysiological mechanisms that underlie distinct genetic or environmentally, i.e., pharmacological and lifestyle, induced renal transport deficits. Specifically, the ease of drug administration and the exploitation of improved genetic approaches might argue for the adoption of the zebrafish as a model for preclinical personalized medicine for distinct renal diseases and renal electrolyte transport proteins.
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Affiliation(s)
- Simone Kersten
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands; and
- Nephrology Division, Department of Medicine, Massachusetts General Hospital, Charlestown, Massachusetts
| | - Francisco J. Arjona
- Department of Physiology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, Nijmegen, The Netherlands; and
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15
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Sayer JA. Progress in Understanding the Genetics of Calcium-Containing Nephrolithiasis. J Am Soc Nephrol 2016; 28:748-759. [PMID: 27932479 DOI: 10.1681/asn.2016050576] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Renal stone disease is a frequent condition, causing a huge burden on health care systems globally. Calcium-based calculi account for around 75% of renal stone disease and the incidence of these calculi is increasing, suggesting environmental and dietary factors are acting upon a preexisting genetic background. The familial nature and significant heritability of stone disease is known, and recent genetic studies have successfully identified genes that may be involved in renal stone formation. The detection of monogenic causes of renal stone disease has been made more feasible by the use of high-throughput sequencing technologies and has also facilitated the discovery of novel monogenic causes of stone disease. However, the majority of calcium stone formers remain of undetermined genotype. Genome-wide association studies and candidate gene studies implicate a series of genes involved in renal tubular handling of lithogenic substrates, such as calcium, oxalate, and phosphate, and of inhibitors of crystallization, such as citrate and magnesium. Additionally, expression profiling of renal tissues from stone formers provides a novel way to explore disease pathways. New animal models to explore these recently-identified mechanisms and therapeutic interventions are being tested, which hopefully will provide translational insights to stop the growing incidence of nephrolithiasis.
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Affiliation(s)
- John A Sayer
- Institute of Genetic Medicine, International Centre for Life, Newcastle University, Newcastle, United Kingdom
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16
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Jansen C, Sahni J, Suzuki S, Horgen FD, Penner R, Fleig A. The coiled-coil domain of zebrafish TRPM7 regulates Mg·nucleotide sensitivity. Sci Rep 2016; 6:33459. [PMID: 27628598 PMCID: PMC5024298 DOI: 10.1038/srep33459] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 08/19/2016] [Indexed: 01/15/2023] Open
Abstract
TRPM7 is a member of the Transient-Receptor-Potential Melastatin ion channel family. TRPM7 is a unique fusion protein of an ion channel and an α-kinase. Although mammalian TRPM7 is well characterized biophysically and its pivotal role in cancer, ischemia and cardiovascular disease is becoming increasingly evident, the study of TRPM7 in mouse models has been hampered by embryonic lethality of transgenic ablations. In zebrafish, functional loss of TRPM7 (drTRPM7) manifests itself in an array of non-lethal physiological malfunctions. Here, we investigate the regulation of wild type drTRPM7 and multiple C-terminal truncation mutants. We find that the biophysical properties of drTRPM7 are very similar to mammalian TRPM7. However, pharmacological profiling reveals that drTRPM7 is facilitated rather than inhibited by 2-APB, and that the TRPM7 inhibitor waixenicin A has no effect. This is reminiscent of the pharmacological profile of human TRPM6, the sister channel kinase of TRPM7. Furthermore, using truncation mutations, we show that the coiled-coil domain of drTRPM7 is involved in the channel's regulation by magnesium (Mg) and Mg·adenosine triphosphate (Mg·ATP). We propose that drTRPM7 has two protein domains that regulate inhibition by intracellular magnesium and nucleotides, and one domain that is concerned with sensing magnesium only.
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Affiliation(s)
- Chad Jansen
- Center for Biomedical Research, The Queen’s Medical Center and University of Hawaii, Honolulu, HI-96813, USA
- University of Hawaii Cancer Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, HI-96813, USA
| | - Jaya Sahni
- Center for Immunity and Immunotherapies, Seattle Children’s Research Institute, 1900 9th Ave, Seattle, WA 98101, USA
| | - Sayuri Suzuki
- Center for Biomedical Research, The Queen’s Medical Center and University of Hawaii, Honolulu, HI-96813, USA
| | - F. David Horgen
- Laboratory of Marine Biological Chemistry, Department of Natural Sciences, Hawaii Pacific University, Kaneohe, HI 96744, USA
| | - Reinhold Penner
- Center for Biomedical Research, The Queen’s Medical Center and University of Hawaii, Honolulu, HI-96813, USA
- University of Hawaii Cancer Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, HI-96813, USA
| | - Andrea Fleig
- Center for Biomedical Research, The Queen’s Medical Center and University of Hawaii, Honolulu, HI-96813, USA
- University of Hawaii Cancer Center and John A. Burns School of Medicine, University of Hawaii, Honolulu, HI-96813, USA
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17
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Abstract
As the processes of embryogenesis become increasingly well understood, there is growing interest in the development that occurs at later, postembryonic stages. Postembryonic development holds tremendous potential for discoveries of both fundamental and translational importance. Zebrafish, which are small, rapidly and externally developing, and which boast a wealth of genetic resources, are an outstanding model of vertebrate postembryonic development. Nonetheless, there are specific challenges posed by working with zebrafish at these stages, and this chapter is meant to serve as a primer for those working with larval and juvenile zebrafish. Since accurate staging is critical for high-quality results and experimental reproducibility, we outline best practices for reporting postembryonic developmental progress. Emphasizing the importance of accurate staging, we present new data showing that rates of growth and size-stage relationships can differ even between wild-type strains. Finally, since rapid and uniform development is particularly critical when working at postembryonic stages, we briefly describe methods that we use to achieve high rates of growth and developmental uniformity through postembryonic stages in both wild-type and growth-compromised zebrafish.
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Affiliation(s)
- S K McMenamin
- University of Massachusetts, Lowell, MA, United States; University of Washington, Seattle, WA, United States
| | - M N Chandless
- University of Washington, Seattle, WA, United States
| | - D M Parichy
- University of Washington, Seattle, WA, United States
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18
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Iguchi A, Watanabe Y, Iino N, Kazama JJ, Iesato H, Narita I. Serum magnesium concentration is inversely associated with fibroblast growth factor 23 in haemodialysis patients. Nephrology (Carlton) 2015; 19:667-71. [PMID: 24899171 DOI: 10.1111/nep.12287] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/01/2014] [Indexed: 12/22/2022]
Abstract
AIM Fibroblast growth factor 23 is reported to be a pivotal regulator for the chronic kidney disease-mineral bone disorders, working in coordinated ways with phosphate, calcium, and parathyroid hormone. However, whether there is a relationship between fibroblast growth factor 23 and magnesium is currently unclear. To address this, we performed a cross-sectional observational study in haemodialysis patients. METHODS We measured the serum levels of fibroblast growth factor 23, magnesium and other factors that are implicated in chronic kidney disease-mineral bone disorders in 225 haemodialysis patients. RESULTS Simple correlation analysis showed that fibroblast growth factor 23 was not correlated with magnesium. However, upon multiple regression analysis, a significant negative correlation was found between fibroblast growth factor 23 and magunesium (b = -0.164, P = 0.0020). Moreover, the levels of fibroblast growth factor 23 in patients treated with magnesium oxide had significantly lower levels than those without magnesium oxide. CONCLUSION We speculate that the magnesium is a potential regulator of fibroblast growth factor 23 levels in haemodialysis patients. Our data suggest that follow-up studies to elucidate the molecular mechanisms that underlie this relationship are warranted.
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Affiliation(s)
- Akira Iguchi
- Department of Internal Medicine, Ojiya General Hospital, Niigata, Japan
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19
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Cheng CN, Wingert RA. Nephron proximal tubule patterning and corpuscles of Stannius formation are regulated by the sim1a transcription factor and retinoic acid in zebrafish. Dev Biol 2014; 399:100-116. [PMID: 25542995 DOI: 10.1016/j.ydbio.2014.12.020] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 11/24/2014] [Accepted: 12/17/2014] [Indexed: 02/06/2023]
Abstract
The mechanisms that establish nephron segments are poorly understood. The zebrafish embryonic kidney, or pronephros, is a simplified yet conserved genetic model to study this renal development process because its nephrons contain segments akin to other vertebrates, including the proximal convoluted and straight tubules (PCT, PST). The zebrafish pronephros is also associated with the corpuscles of Stannius (CS), endocrine glands that regulate calcium and phosphate homeostasis, but whose ontogeny from renal progenitors is largely mysterious. Initial patterning of zebrafish renal progenitors in the intermediate mesoderm (IM) involves the formation of rostral and caudal domains, the former being reliant on retinoic acid (RA) signaling, and the latter being repressed by elevated RA levels. Here, using expression profiling to gain new insights into nephrogenesis, we discovered that the gene single minded family bHLH transcription factor 1a (sim1a) is dynamically expressed in the renal progenitors-first marking the caudal domain, then becoming restricted to the proximal segments, and finally exhibiting specific CS expression. In loss of function studies, sim1a knockdown expanded the PCT and abrogated both the PST and CS populations. Conversely, overexpression of sim1a modestly expanded the PST and CS, while it reduced the PCT. These results show that sim1a activity is necessary and partially sufficient to induce PST and CS fates, and suggest that sim1a may inhibit PCT fate and/or negotiate the PCT/PST boundary. Interestingly, the sim1a expression domain in renal progenitors is responsive to altered levels of RA, suggesting that RA regulates sim1a, directly or indirectly, during nephrogenesis. sim1a deficient embryos treated with exogenous RA formed nephrons that were predominantly composed of PCT segments, but lacked the enlarged PST observed in RA treated wild-types, indicating that RA is not sufficient to rescue the PST in the absence of sim1a expression. Alternately, when sim1a knockdowns were exposed to the RA inhibitor diethylaminobenzaldehyde (DEAB), the CS was abrogated rather than expanded as seen in DEAB treated wild-types, revealing that CS formation in the absence of sim1a cannot be rescued by RA biosynthesis abrogation. Taken together, these data reveal previously unappreciated roles for sim1a in zebrafish pronephric proximal tubule and CS patterning, and are consistent with the model that sim1a acts downstream of RA to mitigate the formation of these lineages. These findings provide new insights into the genetic pathways that direct nephron development, and may have implications for understanding renal birth defects and kidney reprogramming.
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Affiliation(s)
- Christina N Cheng
- Department of Biological Sciences and Center for Zebrafish Research, University of Notre Dame, 100 Galvin Life Sciences, Notre Dame, IN 46556, USA
| | - Rebecca A Wingert
- Department of Biological Sciences and Center for Zebrafish Research, University of Notre Dame, 100 Galvin Life Sciences, Notre Dame, IN 46556, USA.
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20
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Yee NS, Kazi AA, Yee RK. Cellular and Developmental Biology of TRPM7 Channel-Kinase: Implicated Roles in Cancer. Cells 2014; 3:751-77. [PMID: 25079291 PMCID: PMC4197629 DOI: 10.3390/cells3030751] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 07/15/2014] [Accepted: 07/15/2014] [Indexed: 12/29/2022] Open
Abstract
The transient receptor potential melastatin-subfamily member 7 (TRPM7) is a ubiquitously expressed cation-permeable ion channel with intrinsic kinase activity that plays important roles in various physiological functions. Biochemical and electrophysiological studies, in combination with molecular analyses of TRPM7, have generated insights into its functions as a cellular sensor and transducer of physicochemical stimuli. Accumulating evidence indicates that TRPM7 channel-kinase is essential for cellular processes, such as proliferation, survival, differentiation, growth, and migration. Experimental studies in model organisms, such as zebrafish, mouse, and frog, have begun to elucidate the pleiotropic roles of TRPM7 during embryonic development from gastrulation to organogenesis. Aberrant expression and/or activity of the TRPM7 channel-kinase have been implicated in human diseases including a variety of cancer. Studying the functional roles of TRPM7 and the underlying mechanisms in normal cells and developmental processes is expected to help understand how TRPM7 channel-kinase contributes to pathogenesis, such as malignant neoplasia. On the other hand, studies of TRPM7 in diseases, particularly cancer, will help shed new light in the normal functions of TRPM7 under physiological conditions. In this article, we will provide an updated review of the structural features and biological functions of TRPM7, present a summary of current knowledge of its roles in development and cancer, and discuss the potential of TRPM7 as a clinical biomarker and therapeutic target in malignant diseases.
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Affiliation(s)
- Nelson S Yee
- Division of Hematology-Oncology, Department of Medicine, Penn State College of Medicine, Program of Experimental Therapeutics, Penn State Hershey Cancer Institute, Penn State Milton S, Hershey Medical Center, Pennsylvania State University, Hershey, PA 17033, USA.
| | - Abid A Kazi
- Division of Hematology-Oncology, Department of Medicine, Penn State College of Medicine, Program of Experimental Therapeutics, Penn State Hershey Cancer Institute, Penn State Milton S, Hershey Medical Center, Pennsylvania State University, Hershey, PA 17033, USA.
| | - Rosemary K Yee
- Schreyer Honors College, Pennsylvania State University, University Park, PA 16802, USA; Penn State Harrisburg School of Humanities, Pennsylvania State University, Middletown, PA 17057, USA.
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21
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Abstract
The channel kinases TRPM6 and TRPM7 are fusion proteins with an ion transport domain and an enzymatically active kinase domain. TRPM7 has been found in every mammalian tissue investigated to date. The two-in-one protein structure, the ubiquitous expression profile, and the protein's unique biophysical characteristics that enable divalent ion transport involve TRPM7 in a plethora of (patho)physiological processes. With its prominent role in cellular and systemic magnesium homeostasis, TRPM7 emerges as a key player in embryonic development, global ischemia, cardiovascular disease, and cancer.
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Affiliation(s)
- Andrea Fleig
- Center for Biomedical Research at The Queen's Medical Center, Honolulu, HI, USA,
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22
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Decker AR, McNeill MS, Lambert AM, Overton JD, Chen YC, Lorca RA, Johnson NA, Brockerhoff SE, Mohapatra DP, MacArthur H, Panula P, Masino MA, Runnels LW, Cornell RA. Abnormal differentiation of dopaminergic neurons in zebrafish trpm7 mutant larvae impairs development of the motor pattern. Dev Biol 2013; 386:428-39. [PMID: 24291744 DOI: 10.1016/j.ydbio.2013.11.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 11/01/2013] [Accepted: 11/12/2013] [Indexed: 10/26/2022]
Abstract
Transient receptor potential, melastatin-like 7 (Trpm7) is a combined ion channel and kinase implicated in the differentiation or function of many cell types. Early lethality in mice and frogs depleted of the corresponding gene impedes investigation of the functions of this protein particularly during later stages of development. By contrast, zebrafish trpm7 mutant larvae undergo early morphogenesis normally and thus do not have this limitation. The mutant larvae are characterized by multiple defects including melanocyte cell death, transient paralysis, and an ion imbalance that leads to the development of kidney stones. Here we report a requirement for Trpm7 in differentiation or function of dopaminergic neurons in vivo. First, trpm7 mutant larvae are hypomotile and fail to make a dopamine-dependent developmental transition in swim-bout length. Both of these deficits are partially rescued by the application of levodopa or dopamine. Second, histological analysis reveals that in trpm7 mutants a significant fraction of dopaminergic neurons lack expression of tyrosine hydroxylase, the rate-limiting enzyme in dopamine synthesis. Third, trpm7 mutants are unusually sensitive to the neurotoxin 1-methyl-4-phenylpyridinium, an oxidative stressor, and their motility is partially rescued by application of the iron chelator deferoxamine, an anti-oxidant. Finally, in SH-SY5Y cells, which model aspects of human dopaminergic neurons, forced expression of a channel-dead variant of TRPM7 causes cell death. In summary, a forward genetic screen in zebrafish has revealed that both melanocytes and dopaminergic neurons depend on the ion channel Trpm7. The mechanistic underpinning of this dependence requires further investigation.
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Affiliation(s)
- Amanda R Decker
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, United States
| | - Matthew S McNeill
- Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, United States
| | - Aaron M Lambert
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, United States
| | - Jeffrey D Overton
- UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854, United States
| | - Yu-Chia Chen
- Neuroscience Center and Institute of Biomedicine/Anatomy, University of Helsinki, Helsinki, Finland
| | - Ramón A Lorca
- Department of Pharmacology, University of Iowa, Iowa City, IA 52245, United States
| | - Nicolas A Johnson
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States
| | - Susan E Brockerhoff
- Department of Biochemistry, University of Washington, Seattle, WA 98195, United States
| | - Durga P Mohapatra
- Department of Pharmacology, University of Iowa, Iowa City, IA 52245, United States
| | - Heather MacArthur
- Department of Pharmacological and Physiological Science, St. Louis University, St. Louis, MO 63104, United States
| | - Pertti Panula
- Neuroscience Center and Institute of Biomedicine/Anatomy, University of Helsinki, Helsinki, Finland
| | - Mark A Masino
- Department of Neuroscience, University of Minnesota, Minneapolis, MN 55455, United States
| | - Loren W Runnels
- UMDNJ-Robert Wood Johnson Medical School, Piscataway, NJ 08854, United States
| | - Robert A Cornell
- Department of Anatomy and Cell Biology, University of Iowa, Iowa City, IA 52242, United States; Interdisciplinary Graduate Program in Neuroscience, University of Iowa, Iowa City, IA 52242, United States.
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23
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Kastenhuber E, Gesemann M, Mickoleit M, Neuhauss SCF. Phylogenetic analysis and expression of zebrafish transient receptor potential melastatin family genes. Dev Dyn 2013; 242:1236-49. [PMID: 23908157 DOI: 10.1002/dvdy.24020] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Revised: 07/02/2013] [Accepted: 07/17/2013] [Indexed: 12/31/2022] Open
Abstract
BACKGROUND The transient receptor potential melastatin (TRPM) gene family belongs to the superfamily of nonselective TRP ion channels. TRP channels are cellular sensors, detecting a multitude of inputs, including temperature, light, chemical, and mechanical stimuli. Recent studies revealed diverse roles during development, linking TRP channels to differentiation, proliferation, cell motility, cell death, and survival. A detailed description of this gene family in the zebrafish is still missing. RESULTS Phylogenetic analysis revealed 11 trpm genes in the zebrafish genome. The zebrafish orthologs of mammalian TRPM1 and TRPM4 are duplicated and quadruplicated, respectively, and TRPM8, a cold sensitive channel has been lost in zebrafish. Whole-mount in situ hybridization experiments revealed dynamic expression pattern of trpm genes in the developing embryo and early larva. Transcripts were mainly found in neural cell clusters, but also in tissues involved in ion homeostasis. CONCLUSIONS Our results suggest a role of TRPM channels in sensory information processing, including vision, olfaction, taste, and mechanosensation. An involvement in developmental processes is likely, as some trpm genes were found to be expressed in differentiating cells. Our data now provide a basis for functional analyses of this gene family of ion channels in the vertebrate model organism Danio rerio.
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Affiliation(s)
- Edda Kastenhuber
- Institute of Molecular Life Sciences, University of Zurich, Zurich, Switzerland
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24
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Graham DM, Huang L, Robinson KR, Messerli MA. Epidermal keratinocyte polarity and motility require Ca²⁺ influx through TRPV1. J Cell Sci 2013; 126:4602-13. [PMID: 23943873 DOI: 10.1242/jcs.122192] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Ca(2+) has long been known to play an important role in cellular polarity and guidance. We studied the role of Ca(2+) signaling during random and directed cell migration to better understand whether Ca(2+) directs cell motility from the leading edge and which ion channels are involved in this function by using primary zebrafish keratinocytes. Rapid line-scan and time-lapse imaging of intracellular Ca(2+) (Ca(2+)i) during migration and automated image alignment enabled us to characterize and map the spatiotemporal changes in Ca(2+)i. We show that asymmetric distributions of lamellipodial Ca(2+) sparks are encoded in frequency, not amplitude, and that they correlate with cellular rotation during migration. Directed migration during galvanotaxis increases the frequency of Ca(2+) sparks over the entire lamellipod; however, these events do not give rise to asymmetric Ca(2+)i signals that correlate with turning. We demonstrate that Ca(2+)-permeable channels within these cells are mechanically activated and include several transient receptor potential family members, including TRPV1. Last, we demonstrate that cell motility and Ca(2+)i activity are affected by pharmacological agents that target TRPV1, indicating a novel role for this channel during cell migration.
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Affiliation(s)
- David M Graham
- Eugene Bell Center for Regenerative Biology and Tissue Engineering, Marine Biological Laboratory, Woods Hole, MA 02543, USA
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25
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McMenamin SK, Minchin JEN, Gordon TN, Rawls JF, Parichy DM. Dwarfism and increased adiposity in the gh1 mutant zebrafish vizzini. Endocrinology 2013; 154:1476-87. [PMID: 23456361 PMCID: PMC3602633 DOI: 10.1210/en.2012-1734] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Somatic growth and adipogenesis are closely associated with the development of obesity in humans. In this study, we identify a zebrafish mutant, vizzini, that exhibits both a severe defect in somatic growth and increased accumulation of adipose tissue. Positional cloning of vizzini revealed a premature stop codon in gh1. Although the effects of GH are largely through igfs in mammals, we found no decrease in the expression of igf transcripts in gh1 mutants during larval development. As development progressed, however, we found overall growth to be progressively retarded and the attainment of specific developmental stages to occur at abnormally small body sizes relative to wild type. Moreover, both subcutaneous (sc) and visceral adipose tissues underwent precocious development in vizzini mutants, and at maturity, the sizes of different fat deposits were greatly expanded relative to wild type. In vivo confocal imaging of sc adipose tissue (SAT) expansion revealed that vizzini mutants exhibit extreme enlargement of adipocyte lipid droplets without a corresponding increase in lipid droplet number. These findings suggest that GH1 signaling restricts SAT hypertrophy in zebrafish. Finally, nutrient deprivation of vizzini mutants revealed that SAT mobilization was greatly diminished during caloric restriction, further implicating GH1 signaling in adipose tissue homeostasis. Overall, the zebrafish gh1 mutant, vizzini, exhibits decreased somatic growth, increased adipose tissue accumulation, and disrupted adipose plasticity after nutrient deprivation and represents a novel model to investigate the in vivo dynamics of vertebrate obesity.
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Affiliation(s)
- Sarah K McMenamin
- Department of Biology, University of Washington, Box 351800, Seattle, Washington 98195-1800, USA
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26
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Abstract
The TRPM7 (transient receptor potential melastatin 7) channel has been shown to play a pivotal role in cell survival during brain ischaemia as well as in the survival of other cell types challenged with apoptotic stimuli. Ca(2+) is thought to be central to the channel's ability to regulate ROS (reactive oxygen species) production. However, channel-mediated entry of Mg(2+) and Zn(2+) have also been implicated in cell death. In the present study, we show that depletion of TRPM7 by RNA interference in fibroblasts increases cell resistance to apoptotic stimuli by decreasing ROS levels in an Mg(2+)-dependent manner. Depletion of TRPM7 lowered cellular Mg(2+), decreased the concentration of ROS and lessened p38 MAPK (mitogen-activated protein kinase) and JNK (c-Jun N-terminal kinase) activation as well as decreased caspase 3 activation and PARP [poly(ADP-ribose) polymerase] cleavage in response to apoptotic stimuli. Re-expression of TRPM7 or of a kinase-inactive mutant of TRPM7 in TRPM7-knockdown cells increased cellular Mg(2+) and ROS levels, as did expression of the Mg(2+) transporter SLC41A2 (solute carrier family 41 member 2). In addition, expression of SLC41A2 increased the sensitivity of TRPM7-knockdown cells to apoptotic stimuli and boosted ROS generation in response to cell stress. Taken together, these data uncover an essential role for Mg(2+) in TRPM7's control of cell survival and in the regulation of cellular ROS levels.
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Mangos S, Amaral AP, Faul C, Jüppner H, Reiser J, Wolf M. Expression of fgf23 and αklotho in developing embryonic tissues and adult kidney of the zebrafish, Danio rerio. Nephrol Dial Transplant 2012; 27:4314-22. [PMID: 22885518 DOI: 10.1093/ndt/gfs335] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Fibroblast growth factor 23 (FGF23) is an endocrine hormone that is secreted by bone and acts on the kidney and parathyroid glands to regulate phosphate homeostasis. The effects of FGF23 on phosphate homeostasis are mediated by binding to FGF receptors and their coreceptor, αklotho, which are abundantly expressed in the kidney and parathyroid glands. However, the mechanisms of how FGF23 regulates phosphate handling in the proximal tubule are unclear because αklotho is primarily expressed in the distal nephron in humans and rodents. The purpose of this study was to gain additional insight into the FGF23-αklotho system by investigating the spatial and temporal aspects of the expression of fgf23 and αklotho in the zebrafish, Danio rerio. Here, we report that zebrafish fgf23 begins to be expressed after organogenesis and is continually expressed into adulthood in the corpuscles of Stannius, which are endocrine glands that lie in close proximity to the nephron and are thought to contribute to calcium and phosphate homeostasis in fish. Zebrafish αklotho expression can be detected by 24-h postfertilization in the brain, pancreas and the distal pronephros, and by 56-h postfertilization in liver. Expression in the distal pronephros persists throughout development, and by Day 5, there is also strong expression in the proximal pronephros. αklotho continues to be expressed in the tubules of the metanephros of the adult kidney. These data indicate conservation of the FGF23-αklotho system across species and suggest a likely role for αklotho in the proximal and distal tubules.
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Affiliation(s)
- Steve Mangos
- Division of Nephrology and Hypertension, Department of Medicine, University of Miami Miller School of Medicine, Miami, FL, USA
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Affiliation(s)
- Ivana Y Kuo
- Departments of †Pharmacology and ‡Cellular and Molecular Physiology School of Medicine, Yale University , 333 Cedar Street, New Haven, Connecticut 06520
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Yeung BHY, Law AYS, Wong CKC. Evolution and roles of stanniocalcin. Mol Cell Endocrinol 2012; 349:272-80. [PMID: 22115958 DOI: 10.1016/j.mce.2011.11.007] [Citation(s) in RCA: 157] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 11/07/2011] [Indexed: 12/11/2022]
Abstract
In fish, stanniocalcin-1 (STC1) is a key endocrine factor that acts on gill, intestine and kidney to regulate serum calcium and phosphate homeostasis. The recent identification and study of mammalian STCs (STC1 and STC2) revealed that the hormones are made in virtually all tissues and they act primarily as paracrine/autocrine factors to regulate various biological functions. Based on their ubiquitous expression patterns and generally undetectable levels in blood serum, it is unlikely that the mammalian STCs play important roles in serum Ca(2+)/P(i) homeostasis. However current evidences still support the local action of STCs in Ca(2+) and P(i) transport, probably via their action on Ca(2+)-channels and Na(+)/P(i) co-transporter. At present, information about the sequence, expression and distribution of the STC receptor(s) is lacking. However, recent emerging evidence hints the involvement of STC1 and STC2 in the sub-cellular functions of mitochondria and endoplasmic reticulum respectively, particularly responding to oxidative stress and unfolded protein response. With increasing evidence that demonstrates the local actions of STCs, the focus of the research has been moved to cellular inflammation and carcinogenesis. This review integrates the information available on STCs in fish and mammals, focusing mainly on their embryonic origin, tissue distribution, their potential regulatory mechanisms and the modes of action, and their physiological and pathophysiological functions, particularly in cancer biology.
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Affiliation(s)
- B H Y Yeung
- Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong
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30
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Abstract
MicroRNAs (miRNAs) are endogenous short (20-22 nucleotides) non-coding RNA molecules that mediate gene expression. This is an important regulatory mechanism to modulate fundamental cellular processes such as differentiation, proliferation, death, metabolism, and pathophysiology of many diseases. The miRNA expression profile of the kidney differs greatly from that of other organs, as well as between the different regions in the kidney. In kidneys, miRNAs are indispensable for development and homeostasis. In this review, we explore the involvement of miRNAs in the regulation of blood pressure, hormone, water, and ion balance pertaining to kidney homeostasis. We also highlight their importance in renal pathophysiology, such as in polycystic disease, diabetic nephropathy, nephrogenic diabetes insipidus, hypertension, renal cancer, and kidney fibrosis (epithelial-mesenchymal transition). In addition, we highlight the need for further investigations on miRNA-based studies in the development of diagnostic, prognostic, and therapeutic tools for renal diseases.
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Farooqi AA, Javeed MK, Javed Z, Riaz AM, Mukhtar S, Minhaj S, Abbas S, Bhatti S. TRPM channels: same ballpark, different players, and different rules in immunogenetics. Immunogenetics 2011; 63:773-87. [PMID: 21932052 DOI: 10.1007/s00251-011-0570-4] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2011] [Accepted: 09/02/2011] [Indexed: 11/29/2022]
Abstract
Transient receptor potential (TRP) channels belong to a large family of cation channels and are the "border guards" predominantly localized to the plasma membrane. Research over the years has considerably and highly developed the knowledge of expression and functional aspects of the TRPM channels. A closer look at the channel dynamics has dismantled undeniable substantiation for multifaceted roles for TRPM channel-mediated extracellular Ca(2+) influx in several physiological and pathophysiological functions. Given the wealth of literature unfolding the multiple roles of TRP channels in physiology in a very extensive range of different mammalian tissues, this review confines itself to the literature describing the multiple roles of TRPM channels in diabetes, smooth muscle cell regulation, immunological responses, and emerging aspects of cancer. We also focus on differential activities of TRPM channels after post-transcriptional and post-translational processing and their exquisite roles at various cellular and molecular levels.
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Affiliation(s)
- Ammad Ahmad Farooqi
- Institute of Molecular Biology and Biotechnology (IMBB), The University of Lahore, Punjab, Pakistan.
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Zebrafish: a model system for the study of vertebrate renal development, function, and pathophysiology. Curr Opin Nephrol Hypertens 2011; 20:416-24. [DOI: 10.1097/mnh.0b013e3283477797] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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Vanoevelen J, Janssens A, Huitema LFA, Hammond CL, Metz JR, Flik G, Voets T, Schulte-Merker S. Trpv5/6 is vital for epithelial calcium uptake and bone formation. FASEB J 2011; 25:3197-207. [PMID: 21670068 DOI: 10.1096/fj.11-183145] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Calcium is an essential ion serving a multitude of physiological roles. Aside from its role as a second messenger, it is an essential component of the vertebrate bone matrix. Efficient uptake and storage of calcium are therefore indispensable for all vertebrates. Transient receptor potential family, vanilloid type (TRPV)5 and TRPV6 channels are known players in transcellular calcium uptake, but the exact contribution of this pathway is unclear. We used forward genetic screening in zebrafish (Danio rerio) to identify genes essential in bone formation and identified a lethal zebrafish mutant (matt-und-schlapp) with severe defects in bone formation, including lack of ossification of the vertebral column and craniofacial structures. Mutant embryos show a 68% reduction in calcium content, and systemic calcium homeostasis is disturbed when compared with siblings. The phenotype can be partially rescued by increasing ambient calcium levels to 25 mM. We identified the mutation as a loss-of-function mutation in the single orthologue of TRPV5 and 6, trpv5/6. Expression in HEK293 cells showed that Trpv5/6 is a calcium-selective channel capable of inward calcium transport at physiological concentrations whereas the mutant channel is not. Taken together, this study provides both genetic and functional evidence that transcellular epithelial calcium uptake is vital to sustain life and enable bone formation.
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Affiliation(s)
- Jo Vanoevelen
- Hubrecht Institute, Royal Netherlands Academy of Arts and Sciences and University Medical Centre, Utrecht, The Netherlands.
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Deason-Towne F, Perraud AL, Schmitz C. The Mg2+ transporter MagT1 partially rescues cell growth and Mg2+ uptake in cells lacking the channel-kinase TRPM7. FEBS Lett 2011; 585:2275-8. [PMID: 21627970 DOI: 10.1016/j.febslet.2011.05.052] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2011] [Revised: 05/17/2011] [Accepted: 05/23/2011] [Indexed: 12/31/2022]
Abstract
Magnesium (Mg(2+)) transport across membranes plays an essential role in cellular growth and survival. TRPM7 is the unique fusion of a Mg(2+) permeable pore with an active cytosolic kinase domain, and is considered a master regulator of cellular Mg(2+) homeostasis. We previously found that the genetic deletion of TRPM7 in DT40 B cells results in Mg(2+) deficiency and severe growth impairment, which can be rescued by supplementation with excess extracellular Mg(2+). Here, we show that gene expression of the Mg(2+) selective transporter MagT1 is upregulated in TRPM7(-/-) cells. Furthermore, overexpression of MagT1 in TRPM7(-/-) cells augments their capacity to uptake Mg(2+), and improves their growth behavior in the absence of excess Mg(2+).
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Affiliation(s)
- Francina Deason-Towne
- Integrated Department of Immunology, National Jewish Health and University of Colorado, Denver, CO 80206, USA
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Abstract
TRPM7 (transient receptor potential melastatin 7) is a Ca²+- and Mg²+-permeant ion channel in possession of its own kinase domain. As a kinase, the protein has been linked to the control of actomyosin contractility, whereas the channel has been found to regulate cell adhesion as well as cellular Mg²+ homoeostasis. In the present study we show that depletion of TRPM7 by RNA interference in fibroblasts alters cell morphology, the cytoskeleton, and the ability of cells to form lamellipodia and to execute polarized cell movements. A pulldown-purification assay revealed that knockdown of TRPM7 prevents cells from activating Rac and Cdc42 (cell division cycle 42) when stimulated to migrate into a cellular wound. Re-expression of TRPM7 reverses these phenotypic changes, as does, unexpectedly, expression of a kinase-inactive mutant of TRPM7. Surprisingly, expression of the Mg²+ transporter SLC41A2 (solute carrier family 41 member 2) is also effective in restoring the change in cell morphology, disruption of the cytoskeleton and directional cell motility caused by depletion of the channel-kinase. The results of the present study uncover an essential role for Mg²+ in the control of TRPM7 over the cytoskeleton and its ability to regulate polarized cell movements.
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