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Amioka N, Franklin MK, Kukida M, Sawada H, Moorleghen JJ, Howatt DA, Katsumata Y, Mullick AE, Yanagita M, Martinez-Irizarry MM, Sandoval RM, Dunn KW, Daugherty A, Lu HS. Renal Proximal Tubule Cell-specific Megalin Deletion Does Not Affect Atherosclerosis But Induces Tubulointerstitial Nephritis in Mice Fed Western Diet. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.11.592234. [PMID: 38798535 PMCID: PMC11118422 DOI: 10.1101/2024.05.11.592234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
Background Pharmacological inhibition of megalin (also known as low-density lipoprotein receptor-related protein 2: LRP2) attenuates atherosclerosis in hypercholesterolemic mice. Since megalin is abundant in renal proximal tubule cells (PTCs), the purpose of this study was to determine whether PTC-specific deletion of megalin reduces hypercholesterolemia-induced atherosclerosis in mice. Methods Female Lrp2 f/f mice were bred with male Ndrg1-Cre ERT2 +/0 mice to develop PTC-LRP2 +/+ and -/- littermates. To study atherosclerosis, all mice were to bred to an LDL receptor -/- background and fed a Western diet to induce atherosclerosis. Results PTC-specific megalin deletion did not attenuate atherosclerosis in LDL receptor -/- mice in either sex. Serendipitously, we discovered that PTC-specific megalin deletion led to interstitial infiltration of CD68+ cells and tubular atrophy. The pathology was only evident in male PTC-LRP2 -/- mice fed the Western diet, but not in mice fed a normal laboratory diet. Renal pathologies were also observed in male PTC-LRP2 -/- mice in an LDL receptor +/+ background fed the same Western diet, demonstrating that the renal pathologies were dependent on diet and not hypercholesterolemia. By contrast, female PTC-LRP2 -/- mice had no apparent renal pathologies. In vivo multiphoton microscopy demonstrated that PTC-specific megalin deletion dramatically diminished albumin accumulation in PTCs within 10 days of Western diet feeding. RNA sequencing analyses demonstrated the upregulation of inflammation-related pathways in kidney. Conclusions PTC-specific megalin deletion does not affect atherosclerosis, but leads to tubulointerstitial nephritis in mice fed Western diet, with severe pathologies in male mice.
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Affiliation(s)
- Naofumi Amioka
- Saha Cardiovascular Research Center and Saha Aortic Center, University of Kentucky, Lexington, Kentucky, USA
| | - Michael K. Franklin
- Saha Cardiovascular Research Center and Saha Aortic Center, University of Kentucky, Lexington, Kentucky, USA
| | - Masayoshi Kukida
- Saha Cardiovascular Research Center and Saha Aortic Center, University of Kentucky, Lexington, Kentucky, USA
| | - Hisashi Sawada
- Saha Cardiovascular Research Center and Saha Aortic Center, University of Kentucky, Lexington, Kentucky, USA
- Department of Physiology, University of Kentucky, Lexington, Kentucky, USA
| | - Jessica J. Moorleghen
- Saha Cardiovascular Research Center and Saha Aortic Center, University of Kentucky, Lexington, Kentucky, USA
| | - Deborah A. Howatt
- Saha Cardiovascular Research Center and Saha Aortic Center, University of Kentucky, Lexington, Kentucky, USA
| | - Yuriko Katsumata
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, Kentucky, USA
- Department of Biostatistics, University of Kentucky, Lexington, Kentucky, USA
| | | | - Motoko Yanagita
- Department of Nephrology, Kyoto University Graduate School of Medicine, Kyoto, Japan
- Institute for the Advanced Study of Human Biology (WPI-ASHBi), Kyoto University, Kyoto, Japan
| | | | - Ruben M. Sandoval
- Department of Medicine, Indiana University, Indianapolis, Indiana, USA
| | - Kenneth W. Dunn
- Department of Medicine, Indiana University, Indianapolis, Indiana, USA
| | - Alan Daugherty
- Saha Cardiovascular Research Center and Saha Aortic Center, University of Kentucky, Lexington, Kentucky, USA
- Department of Physiology, University of Kentucky, Lexington, Kentucky, USA
| | - Hong S. Lu
- Saha Cardiovascular Research Center and Saha Aortic Center, University of Kentucky, Lexington, Kentucky, USA
- Department of Physiology, University of Kentucky, Lexington, Kentucky, USA
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Goto S, Tsutsumi A, Lee Y, Hosojima M, Kabasawa H, Komochi K, Nagatoishi S, Takemoto K, Tsumoto K, Nishizawa T, Kikkawa M, Saito A. Cryo-EM structures elucidate the multiligand receptor nature of megalin. Proc Natl Acad Sci U S A 2024; 121:e2318859121. [PMID: 38771880 PMCID: PMC11145282 DOI: 10.1073/pnas.2318859121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Accepted: 04/19/2024] [Indexed: 05/23/2024] Open
Abstract
Megalin (low-density lipoprotein receptor-related protein 2) is a giant glycoprotein of about 600 kDa, mediating the endocytosis of more than 60 ligands, including those of proteins, peptides, and drug compounds [S. Goto, M. Hosojima, H. Kabasawa, A. Saito, Int. J. Biochem. Cell Biol. 157, 106393 (2023)]. It is expressed predominantly in renal proximal tubule epithelial cells, as well as in the brain, lungs, eyes, inner ear, thyroid gland, and placenta. Megalin is also known to mediate the endocytosis of toxic compounds, particularly those that cause renal and hearing disorders [Y. Hori et al., J. Am. Soc. Nephrol. 28, 1783-1791 (2017)]. Genetic megalin deficiency causes Donnai-Barrow syndrome/facio-oculo-acoustico-renal syndrome in humans. However, it is not known how megalin interacts with such a wide variety of ligands and plays pathological roles in various organs. In this study, we elucidated the dimeric architecture of megalin, purified from rat kidneys, using cryoelectron microscopy. The maps revealed the densities of endogenous ligands bound to various regions throughout the dimer, elucidating the multiligand receptor nature of megalin. We also determined the structure of megalin in complex with receptor-associated protein, a molecular chaperone for megalin. The results will facilitate further studies on the pathophysiology of megalin-dependent multiligand endocytic pathways in multiple organs and will also be useful for the development of megalin-targeted drugs for renal and hearing disorders, Alzheimer's disease [B. V. Zlokovic et al., Proc. Natl. Acad. Sci. U.S.A. 93, 4229-4234 (1996)], and other illnesses.
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Affiliation(s)
- Sawako Goto
- Department of Applied Molecular Medicine, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata City951-8510, Japan
| | - Akihisa Tsutsumi
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo113-0033, Japan
| | - Yongchan Lee
- Department of the Biological Membrane Dynamics, Graduate School of Medical Life Science, Yokohama City University, Yokohama230-0045, Japan
| | - Michihiro Hosojima
- Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata City951-8510, Japan
| | - Hideyuki Kabasawa
- Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata City951-8510, Japan
| | - Koichi Komochi
- Department of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata City951-8510, Japan
| | - Satoru Nagatoishi
- Medical Device Development and Regulation Research Center, School of Engineering, The University of Tokyo, Tokyo113-8656, Japan
| | - Kazuya Takemoto
- Department of Applied Molecular Medicine, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata City951-8510, Japan
| | - Kouhei Tsumoto
- Department of Bioengineering, School of Engineering, The University of Tokyo, Tokyo113-8656, Japan
| | - Tomohiro Nishizawa
- Department of the Biological Membrane Dynamics, Graduate School of Medical Life Science, Yokohama City University, Yokohama230-0045, Japan
| | - Masahide Kikkawa
- Department of Cell Biology and Anatomy, Graduate School of Medicine, The University of Tokyo, Tokyo113-0033, Japan
| | - Akihiko Saito
- Department of Applied Molecular Medicine, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata City951-8510, Japan
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Yi W, Lv D, Sun Y, Mu J, Lu X. Role of APOE in glaucoma. Biochem Biophys Res Commun 2024; 694:149414. [PMID: 38145596 DOI: 10.1016/j.bbrc.2023.149414] [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: 10/27/2023] [Revised: 12/15/2023] [Accepted: 12/19/2023] [Indexed: 12/27/2023]
Abstract
Glaucoma is a chronic blinding eye disease caused by the progressive loss of retinal ganglion cells (RGCs). Currently, no clinically approved treatment can directly improve the survival rate of RGCs. The Apolipoprotein E (APOE) gene is closely related to the genetic risk of numerous neurodegenerative diseases and has become a hot topic in the field of neurodegenerative disease research in recent years. The optic nerve and retina are extensions of the brain's nervous system. The pathogenesis of retinal degenerative diseases is closely related to the degenerative diseases of the nerves in the brain. APOE consists of three alleles, ε4, ε3, and ε2, in a single locus. They have varying degrees of risk for glaucoma. APOE4 and the APOE gene deletion (APOE-/-) can reduce RGC loss. By contrast, APOE3 and the overall presence of APOE genes (APOE+/+) result in significant loss of RGC bodies and axons, increasing the risk of glaucoma RGCs death. Currently, there is no clear literature indicating that APOE2 is beneficial or harmful to glaucoma. This study summarises the mechanism of different APOE genes in glaucoma and speculates that APOE targeted intervention may be a promising method for protecting against RGCs loss in glaucoma.
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Affiliation(s)
- Wenhua Yi
- Eye School of Chengdu University of TCM, Chengdu City, Sichuan province, China.
| | - De Lv
- Department of Endocrinology, Hospital of Chengdu University of Traditional Chinese Medicine, China.
| | - Yue Sun
- Eye School of Chengdu University of TCM, Chengdu City, Sichuan province, China.
| | - Jingyu Mu
- Eye School of Chengdu University of TCM, Chengdu City, Sichuan province, China.
| | - Xuejing Lu
- Eye School of Chengdu University of TCM, Chengdu City, Sichuan province, China; Ineye Hospital of Chengdu University of TCM, Chengdu City, Sichuan province, China; Key Laboratory of Sichuan Province Ophthalmopathy Prevention & Cure and Visual Function Protection with TCM Laboratory, Chengdu City, Sichuan province, China; Retinal Image Technology and Chronic Vascular Disease Prevention&Control and Collaborative Innovation Center, Chengdu City, Sichuan province, China.
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da Cunha JI, Barauna AMD, Garcez RC. Prechordal structures act cooperatively in early trabeculae development of gnathostome skull. Cells Dev 2023; 176:203879. [PMID: 37844659 DOI: 10.1016/j.cdev.2023.203879] [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: 03/29/2023] [Revised: 10/04/2023] [Accepted: 10/13/2023] [Indexed: 10/18/2023]
Abstract
The vertebrate skull is formed by mesoderm and neural crest (NC) cells. The mesoderm contributes to the skull chordal domain, with the notochord playing an essential role in this process. The NC contributes to the skull prechordal domain, prompting investigation into the embryonic structures involved in prechordal neurocranium cartilage formation. The trabeculae cartilage, a structure of the prechordal neurocranium, arises at the convergence of prechordal plate (PCP), ventral midline (VM) cells of the diencephalon, and dorsal oral ectoderm. This study examines the molecular participation of these embryonic structures in gnathostome trabeculae development. PCP-secreted SHH induces its expression in VM cells of the diencephalon, initiating a positive feedback loop involving SIX3 and GLI1. SHH secreted by the VM cells of the diencephalon acts on the dorsal oral ectoderm, stimulating condensation of NC cells to form trabeculae. SHH from the prechordal region affects the expression of SOX9 in NC cells. BMP7 and SHH secreted by PCP induce NKX2.1 expression in VM cells of the diencephalon, but this does not impact trabeculae formation. Molecular cooperation between PCP, VM cells of the diencephalon, and dorsal oral ectoderm is crucial for craniofacial development by NC cells in the prechordal domain.
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Affiliation(s)
- Jaqueline Isoppo da Cunha
- Graduate Program of Cell and Developmental Biology, Federal University of Santa Catarina, Florianopolis, SC, Brazil; Stem Cell and Tissue Regeneration Laboratory (LACERT), Federal University of Santa Catarina, Florianopolis, SC, Brazil
| | - Alessandra Maria Duarte Barauna
- Graduate Program of Cell and Developmental Biology, Federal University of Santa Catarina, Florianopolis, SC, Brazil; Stem Cell and Tissue Regeneration Laboratory (LACERT), Federal University of Santa Catarina, Florianopolis, SC, Brazil
| | - Ricardo Castilho Garcez
- Graduate Program of Cell and Developmental Biology, Federal University of Santa Catarina, Florianopolis, SC, Brazil; Stem Cell and Tissue Regeneration Laboratory (LACERT), Federal University of Santa Catarina, Florianopolis, SC, Brazil; Department of Cell Biology, Embryology, and Genetics, Federal University of Santa Catarina, Florianopolis, SC, Brazil.
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5
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Kho I, Demina EP, Pan X, Londono I, Cairo CW, Sturiale L, Palmigiano A, Messina A, Garozzo D, Ung RV, Mac-Way F, Bonneil É, Thibault P, Lemaire M, Morales CR, Pshezhetsky AV. Severe kidney dysfunction in sialidosis mice reveals an essential role for neuraminidase 1 in reabsorption. JCI Insight 2023; 8:e166470. [PMID: 37698928 PMCID: PMC10619504 DOI: 10.1172/jci.insight.166470] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2022] [Accepted: 09/06/2023] [Indexed: 09/14/2023] Open
Abstract
Sialidosis is an ultra-rare multisystemic lysosomal disease caused by mutations in the neuraminidase 1 (NEU1) gene. The severe type II form of the disease manifests with a prenatal/infantile or juvenile onset, bone abnormalities, severe neuropathology, and visceromegaly. A subset of these patients present with nephrosialidosis, characterized by abrupt onset of fulminant glomerular nephropathy. We studied the pathophysiological mechanism of the disease in 2 NEU1-deficient mouse models, a constitutive Neu1-knockout, Neu1ΔEx3, and a conditional phagocyte-specific knockout, Neu1Cx3cr1ΔEx3. Mice of both strains exhibited terminal urinary retention and severe kidney damage with elevated urinary albumin levels, loss of nephrons, renal fibrosis, presence of storage vacuoles, and dysmorphic mitochondria in the intraglomerular and tubular cells. Glycoprotein sialylation in glomeruli, proximal distal tubules, and distal tubules was drastically increased, including that of an endocytic reabsorption receptor megalin. The pool of megalin bearing O-linked glycans with terminal galactose residues, essential for protein targeting and activity, was reduced to below detection levels. Megalin levels were severely reduced, and the protein was directed to lysosomes instead of the apical membrane. Together, our results demonstrated that desialylation by NEU1 plays a crucial role in processing and cellular trafficking of megalin and that NEU1 deficiency in sialidosis impairs megalin-mediated protein reabsorption.
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Affiliation(s)
- Ikhui Kho
- CHU Sainte-Justine Research Center, University of Montreal, Montreal, Québec, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Québec, Canada
| | - Ekaterina P. Demina
- CHU Sainte-Justine Research Center, University of Montreal, Montreal, Québec, Canada
| | - Xuefang Pan
- CHU Sainte-Justine Research Center, University of Montreal, Montreal, Québec, Canada
| | - Irene Londono
- CHU Sainte-Justine Research Center, University of Montreal, Montreal, Québec, Canada
| | | | - Luisa Sturiale
- CNR, Institute for Polymers, Composites and Biomaterials, Catania, Italy
| | - Angelo Palmigiano
- CNR, Institute for Polymers, Composites and Biomaterials, Catania, Italy
| | - Angela Messina
- CNR, Institute for Polymers, Composites and Biomaterials, Catania, Italy
| | - Domenico Garozzo
- CNR, Institute for Polymers, Composites and Biomaterials, Catania, Italy
| | - Roth-Visal Ung
- CHU de Québec Research Center, L’Hôtel-Dieu de Québec Hospital, Faculty and Department of Medicine, University Laval, Québec City, Québec, Canada
| | - Fabrice Mac-Way
- CHU de Québec Research Center, L’Hôtel-Dieu de Québec Hospital, Faculty and Department of Medicine, University Laval, Québec City, Québec, Canada
| | - Éric Bonneil
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Québec, Canada
| | - Pierre Thibault
- Institute for Research in Immunology and Cancer, University of Montreal, Montreal, Québec, Canada
| | - Mathieu Lemaire
- Division of Nephrology, The Hospital for Sick Kids, Faculty of Medicine, University of Toronto, Ontario, Canada
- Cell Biology Program, SickKids Research Institute, Toronto, Ontario, Canada
| | - Carlos R. Morales
- Department of Anatomy and Cell Biology, McGill University, Montreal, Québec, Canada
| | - Alexey V. Pshezhetsky
- CHU Sainte-Justine Research Center, University of Montreal, Montreal, Québec, Canada
- Department of Anatomy and Cell Biology, McGill University, Montreal, Québec, Canada
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6
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Polenghi M, Taverna E. Intracellular traffic and polarity in brain development. Front Neurosci 2023; 17:1172016. [PMID: 37859764 PMCID: PMC10583573 DOI: 10.3389/fnins.2023.1172016] [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: 02/22/2023] [Accepted: 07/31/2023] [Indexed: 10/21/2023] Open
Abstract
Neurons forming the human brain are generated during embryonic development by neural stem and progenitor cells via a process called neurogenesis. A crucial feature contributing to neural stem cell morphological and functional heterogeneity is cell polarity, defined as asymmetric distribution of cellular components. Cell polarity is built and maintained thanks to the interplay between polarity proteins and polarity-generating organelles, such as the endoplasmic reticulum (ER) and the Golgi apparatus (GA). ER and GA affect the distribution of membrane components and work as a hub where glycans are added to nascent proteins and lipids. In the last decades our knowledge on the role of polarity in neural stem and progenitor cells have increased tremendously. However, the role of traffic and associated glycosylation in neural stem and progenitor cells is still relatively underexplored. In this review, we discuss the link between cell polarity, architecture, identity and intracellular traffic, and highlight how studies on neurons have shaped our knowledge and conceptual framework on traffic and polarity. We will then conclude by discussing how a group of rare diseases, called congenital disorders of glycosylation (CDG) offers the unique opportunity to study the contribution of traffic and glycosylation in the context of neurodevelopment.
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Keuls RA, Finnell RH, Parchem RJ. Maternal metabolism influences neural tube closure. Trends Endocrinol Metab 2023; 34:539-553. [PMID: 37468429 PMCID: PMC10529122 DOI: 10.1016/j.tem.2023.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 06/14/2023] [Accepted: 06/19/2023] [Indexed: 07/21/2023]
Abstract
Changes in maternal nutrient availability due to diet or disease significantly increase the risk of neural tube defects (NTDs). Because the incidence of metabolic disease continues to rise, it is urgent that we better understand how altered maternal nutrient levels can influence embryonic neural tube development. Furthermore, primary neurulation occurs before placental function during a period of histiotrophic nutrient exchange. In this review we detail how maternal metabolites are transported by the yolk sac to the developing embryo. We discuss recent advances in understanding how altered maternal levels of essential nutrients disrupt development of the neuroepithelium, and identify points of intersection between metabolic pathways that are crucial for NTD prevention.
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Affiliation(s)
- Rachel A Keuls
- Development, Disease Models, and Therapeutics Graduate Program, Baylor College of Medicine. Houston, TX 77030, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA; Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA; Stem Cells and Regenerative Medicine Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Richard H Finnell
- Departments of Molecular and Human Genetics and Medicine, Baylor College of Medicine, Houston, TX 77030, USA; Center for Precision Environmental Health, Department of Molecular and Cellular Biology and Medicine, Baylor College of Medicine, Houston, TX 77030, USA
| | - Ronald J Parchem
- Development, Disease Models, and Therapeutics Graduate Program, Baylor College of Medicine. Houston, TX 77030, USA; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, TX 77030, USA; Center for Cell and Gene Therapy, Baylor College of Medicine, Houston, TX 77030, USA; Stem Cells and Regenerative Medicine Center, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
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Schröder SK, Gasterich N, Weiskirchen S, Weiskirchen R. Lipocalin 2 receptors: facts, fictions, and myths. Front Immunol 2023; 14:1229885. [PMID: 37638032 PMCID: PMC10451079 DOI: 10.3389/fimmu.2023.1229885] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Accepted: 07/18/2023] [Indexed: 08/29/2023] Open
Abstract
The human 25-kDa Lipocalin 2 (LCN2) was first identified and purified as a protein that in part is associated with gelatinase from neutrophils. This protein shows a high degree of sequence similarity with the deduced sequences of rat α2-microglobulin-related protein and the mouse protein 24p3. Based on its typical lipocalin fold, which consists of an eight-stranded, anti-parallel, symmetrical β-barrel fold structure it was initially thought that LCN2 is a circulating protein functioning as a transporter of small lipophilic molecules. However, studies in Lcn2 null mice have shown that LCN2 has bacteriostatic properties and plays a key role in innate immunity by sequestering bacterial iron siderophores. Numerous reports have further shown that LCN2 is involved in the control of cell differentiation, energy expenditure, cell death, chemotaxis, cell migration, and many other biological processes. In addition, important roles for LCN2 in health and disease have been identified in Lcn2 null mice and multiple molecular pathways required for regulation of Lcn2 expression have been identified. Nevertheless, although six putative receptors for LCN2 have been proposed, there is a fundamental lack in understanding of how these cell-surface receptors transmit and amplify LCN2 to the cell. In the present review we summarize the current knowledge on LCN2 receptors and discuss inconsistencies, misinterpretations and false assumptions in the understanding of these potential LCN2 receptors.
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Affiliation(s)
- Sarah K. Schröder
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH University Hospital Aachen, Aachen, Germany
| | - Natalie Gasterich
- Institute of Neuroanatomy, RWTH University Hospital Aachen, Aachen, Germany
| | - Sabine Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH University Hospital Aachen, Aachen, Germany
| | - Ralf Weiskirchen
- Institute of Molecular Pathobiochemistry, Experimental Gene Therapy and Clinical Chemistry (IFMPEGKC), RWTH University Hospital Aachen, Aachen, Germany
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Faridi R, Yousaf R, Gu S, Inagaki S, Turriff AE, Pelstring K, Guan B, Naik A, Griffith AJ, Adadey SM, Aboagye ET, Awandare GA, Morell RJ, Tsilou E, Noyes AG, Sulmonte LAG, Wonkam A, Schrauwen I, Leal SM, Azaiez H, Brewer CC, Riazuddin S, Hufnagel RB, Hoa M, Zein WM, de Dios JK, Friedman TB. Variants of LRP2, encoding a multifunctional cell-surface endocytic receptor, associated with hearing loss and retinal dystrophy. Clin Genet 2023; 103:699-703. [PMID: 36807241 DOI: 10.1111/cge.14312] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 02/06/2023] [Accepted: 02/12/2023] [Indexed: 02/22/2023]
Abstract
Hereditary deafness and retinal dystrophy are each genetically heterogenous and clinically variable. Three small unrelated families segregating the combination of deafness and retinal dystrophy were studied by exome sequencing (ES). The proband of Family 1 was found to be compound heterozygous for NM_004525.3: LRP2: c.5005A > G, p.(Asn1669Asp) and c.149C > G, p.(Thr50Ser). In Family 2, two sisters were found to be compound heterozygous for LRP2 variants, p.(Tyr3933Cys) and an experimentally confirmed c.7715 + 3A > T consensus splice-altering variant. In Family 3, the proband is compound heterozygous for a consensus donor splice site variant LRP2: c.8452_8452 + 1del and p.(Cys3150Tyr). In mouse cochlea, Lrp2 is expressed abundantly in the stria vascularis marginal cells demonstrated by smFISH, single-cell and single-nucleus RNAseq, suggesting that a deficiency of LRP2 may compromise the endocochlear potential, which is required for hearing. LRP2 variants have been associated with Donnai-Barrow syndrome and other multisystem pleiotropic phenotypes different from the phenotypes of the four cases reported herein. Our data expand the phenotypic spectrum associated with pathogenic variants in LRP2 warranting their consideration in individuals with a combination of hereditary hearing loss and retinal dystrophy.
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Affiliation(s)
- Rabia Faridi
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Rizwan Yousaf
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Shoujun Gu
- Auditory Development and Restoration Program, NIDCD, NIH, Bethesda, Maryland, USA
| | - Sayaka Inagaki
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health (NIH), Bethesda, Maryland, USA
| | - Amy E Turriff
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Keith Pelstring
- Division of Medical Genetics, Dayton Children's Hospital, Dayton, Ohio, USA
| | - Bin Guan
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Amelia Naik
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, NIH, Bethesda, Maryland, USA
| | | | - Samuel Mawuli Adadey
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Division of Human Genetics, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Elvis Twumasi Aboagye
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
- Division of Human Genetics, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Gordon A Awandare
- West African Centre for Cell Biology of Infectious Pathogens (WACCBIP), University of Ghana, Accra, Ghana
| | - Robert J Morell
- Genomics and Computational Biology Core, NIDCD, NIH, Bethesda, Maryland, USA
| | - Ekaterini Tsilou
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, NIH, Bethesda, Maryland, USA
| | | | | | - Ambroise Wonkam
- Division of Human Genetics, Department of Medicine, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- McKusick-Nathans Institute and Department of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Isabelle Schrauwen
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Center, New York, New York, USA
| | - Suzanne M Leal
- Center for Statistical Genetics, Gertrude H. Sergievsky Center, and the Department of Neurology, Columbia University Medical Center, New York, New York, USA
- Taub Institute for Alzheimer's Disease and the Aging Brain, Columbia University Medical Center, New York, New York, USA
| | - Hela Azaiez
- Molecular Otolaryngology and Renal Research Laboratories, Department of Otolaryngology, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA
| | | | - Sheikh Riazuddin
- Allama Iqbal Medical Research Centre, Jinnah Hospital Complex, Lahore, Pakistan
| | - Robert B Hufnagel
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, NIH, Bethesda, Maryland, USA
| | - Michael Hoa
- Auditory Development and Restoration Program, NIDCD, NIH, Bethesda, Maryland, USA
| | - Wadih M Zein
- Ophthalmic Genetics and Visual Function Branch, National Eye Institute, NIH, Bethesda, Maryland, USA
| | - J Karl de Dios
- Division of Medical Genetics, Dayton Children's Hospital, Dayton, Ohio, USA
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders (NIDCD), National Institutes of Health (NIH), Bethesda, Maryland, USA
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10
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Goto S, Hosojima M, Kabasawa H, Saito A. The endocytosis receptor megalin: From bench to bedside. Int J Biochem Cell Biol 2023; 157:106393. [PMID: 36863658 DOI: 10.1016/j.biocel.2023.106393] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/27/2023] [Indexed: 03/04/2023]
Abstract
The large (∼600 kDa) endocytosis receptor megalin/low-density lipoprotein receptor-related protein 2 is highly expressed at the apical membrane of proximal tubular epithelial cells (PTECs). Megalin plays an important role in the endocytosis of various ligands via interactions with intracellular adaptor proteins, which mediate the trafficking of megalin in PTECs. Megalin mediates the retrieval of essential substances, including carrier-bound vitamins and elements, and impairment of the endocytic process may result in the loss of those substances. In addition, megalin reabsorbs nephrotoxic substances such as antimicrobial (colistin, vancomycin, and gentamicin) or anticancer (cisplatin) drugs and advanced glycation end product-modified or fatty acid-containing albumin. The megalin-mediated uptake of these nephrotoxic ligands causes metabolic overload in PTECs and leads to kidney injury. Blockade or suppression of the megalin-mediated endocytosis of nephrotoxic substances may represent a novel therapeutic strategy for drug-induced nephrotoxicity or metabolic kidney disease. Megalin reabsorbs urinary biomarker proteins such as albumin, α1-microglobulin, β2-microglobulin, and liver-type fatty acid-binding protein; thus, the above-mentioned megalin-targeted therapy may have an effect on the urinary excretion of these biomarkers. We have previously established a sandwich enzyme-linked immunosorbent assay to measure the ectodomain (A-megalin) and full-length (C-megalin) forms of urinary megalin using monoclonal antibodies against the amino- and carboxyl-terminals of megalin, respectively, and reported their clinical usefulness. In addition, there have been reports of patients with novel pathological anti-brush border autoantibodies targeting megalin in the kidney. Even with these breakthroughs in the characterization of megalin, a large number of issues remain to be addressed in future research.
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Affiliation(s)
- Sawako Goto
- Departments of Applied Molecular Medicine, Japan
| | - Michihiro Hosojima
- Departments of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata City, Niigata, Japan
| | - Hideyuki Kabasawa
- Departments of Clinical Nutrition Science, Kidney Research Center, Niigata University Graduate School of Medical and Dental Sciences, Niigata City, Niigata, Japan
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11
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Rasmussen MQ, Tindbæk G, Nielsen MM, Merrild C, Steiniche T, Pedersen JS, Moestrup SK, Degn SE, Madsen M. Epigenetic Silencing of LRP2 Is Associated with Dedifferentiation and Poor Survival in Multiple Solid Tumor Types. Cancers (Basel) 2023; 15:cancers15061830. [PMID: 36980716 PMCID: PMC10046670 DOI: 10.3390/cancers15061830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2023] [Revised: 03/07/2023] [Accepted: 03/09/2023] [Indexed: 03/30/2023] Open
Abstract
More than 80% of human cancers originate in epithelial tissues. Loss of epithelial cell characteristics are hallmarks of tumor development. Receptor-mediated endocytosis is a key function of absorptive epithelial cells with importance for cellular and organismal homeostasis. LRP2 (megalin) is the largest known endocytic membrane receptor and is essential for endocytosis of various ligands in specialized epithelia, including the proximal tubules of the kidney, the thyroid gland, and breast glandular epithelium. However, the role and regulation of LRP2 in cancers that arise from these tissues has not been delineated. Here, we examined the expression of LRP2 across 33 cancer types in The Cancer Genome Atlas. As expected, the highest levels of LRP2 were found in cancer types that arise from LRP2-expressing absorptive epithelial cells. However, in a subset of tumors from these cancer types, we observed epigenetic silencing of LRP2. LRP2 expression showed a strong inverse correlation to methylation of a specific CpG site (cg02361027) in the first intron of the LRP2 gene. Interestingly, low expression of LRP2 was associated with poor patient outcome in clear cell renal cell carcinoma, papillary renal cell carcinoma, mesothelioma, papillary thyroid carcinoma, and invasive breast carcinoma. Furthermore, loss of LRP2 expression was associated with dedifferentiated histological and molecular subtypes of these cancers. These observations now motivate further studies on the functional role of LRP2 in tumors of epithelial origin and the potential use of LRP2 as a cancer biomarker.
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Affiliation(s)
| | - Gitte Tindbæk
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
- Department of Clinical Biochemistry, Horsens Regional Hospital, 8700 Horsens, Denmark
| | - Morten Muhlig Nielsen
- Department of Molecular Medicine (MOMA), Aarhus University Hospital, 8200 Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, 8200 Aarhus, Denmark
| | - Camilla Merrild
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | - Torben Steiniche
- Department of Pathology, Aarhus University Hospital, 8200 Aarhus, Denmark
| | - Jakob Skou Pedersen
- Department of Molecular Medicine (MOMA), Aarhus University Hospital, 8200 Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, 8200 Aarhus, Denmark
- Bioinformatics Research Center (BiRC), Aarhus University, 8000 Aarhus, Denmark
| | - Søren K Moestrup
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
- Department of Cancer and Inflammation Research, University of Southern Denmark, 5230 Odense, Denmark
| | - Søren E Degn
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
| | - Mette Madsen
- Department of Biomedicine, Aarhus University, 8000 Aarhus, Denmark
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12
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Garcia J, Krieger KD, Loitz C, Perez LM, Richards ZA, Helou Y, Kregel S, Celada S, Mesaros CA, Bosland M, Gann PH, Willnow TE, Vander Griend D, Kittles R, Prins GS, Penning T, Nonn L. Regulation of Prostate Androgens by Megalin and 25-hydroxyvitamin D Status: Mechanism for High Prostate Androgens in African American Men. CANCER RESEARCH COMMUNICATIONS 2023; 3:371-382. [PMID: 36875158 PMCID: PMC9983358 DOI: 10.1158/2767-9764.crc-22-0362] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Revised: 01/03/2023] [Accepted: 02/03/2023] [Indexed: 02/11/2023]
Abstract
Vitamin D deficiency is associated with an increased risk of prostate cancer mortality and is hypothesized to contribute to prostate cancer aggressiveness and disparities in African American populations. The prostate epithelium was recently shown to express megalin, an endocytic receptor that internalizes circulating globulin-bound hormones, which suggests regulation of intracellular prostate hormone levels. This contrasts with passive diffusion of hormones that is posited by the free hormone hypothesis. Here, we demonstrate that megalin imports testosterone bound to sex hormone-binding globulin into prostate cells. Prostatic loss of Lrp2 (megalin) in a mouse model resulted in reduced prostate testosterone and dihydrotestosterone levels. Megalin expression was regulated and suppressed by 25-hydroxyvitamin D (25D) in cell lines, patient-derived prostate epithelial cells, and prostate tissue explants. In patients, the relationships between hormones support this regulatory mechanism, as prostatic DHT levels are higher in African American men and are inversely correlated with serum 25D status. Megalin levels are reduced in localized prostate cancer by Gleason grade. Our findings suggest that the free hormone hypothesis should be revisited for testosterone and highlight the impact of vitamin D deficiency on prostate androgen levels, which is a known driver of prostate cancer. Thus, we revealed a mechanistic link between vitamin D and prostate cancer disparities observed in African Americans. Significance These findings link vitamin D deficiency and the megalin protein to increased levels of prostate androgens, which may underpin the disparity in lethal prostate cancer in African America men.
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Affiliation(s)
- Jason Garcia
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
| | - Kirsten D. Krieger
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
| | - Candice Loitz
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
| | - Lillian M. Perez
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
- University of Illinois Cancer Center, Chicago, Illinois
| | - Zachary A. Richards
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
| | - Yves Helou
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
| | - Steve Kregel
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
| | - Sasha Celada
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
| | - Clementina A. Mesaros
- Department of Systems Pharmacology & Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
- Center of Excellence in Environmental Toxicology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Maarten Bosland
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
- University of Illinois Cancer Center, Chicago, Illinois
| | - Peter H. Gann
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
- University of Illinois Cancer Center, Chicago, Illinois
| | | | - Donald Vander Griend
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
- University of Illinois Cancer Center, Chicago, Illinois
| | - Rick Kittles
- Department of Population Sciences, City of Hope, Duarte, California
| | - Gail S. Prins
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
- University of Illinois Cancer Center, Chicago, Illinois
- Departments of Urology, Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois
| | - Trevor Penning
- Department of Systems Pharmacology & Translational Therapeutics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
- Center of Excellence in Environmental Toxicology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Larisa Nonn
- Department of Pathology, University of Illinois at Chicago, Chicago, Illinois
- University of Illinois Cancer Center, Chicago, Illinois
- Corresponding Author: Larisa Nonn, University of Illinois at Chicago, 130 CSN, MC 847, 840 S. Wood St, Chicago, IL 60612. Phone: 312-996-0194; E-mail:
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13
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Noël A, Yilmaz S, Farrow T, Schexnayder M, Eickelberg O, Jelesijevic T. Sex-Specific Alterations of the Lung Transcriptome at Birth in Mouse Offspring Prenatally Exposed to Vanilla-Flavored E-Cigarette Aerosols and Enhanced Susceptibility to Asthma. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:3710. [PMID: 36834405 PMCID: PMC9967225 DOI: 10.3390/ijerph20043710] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 02/07/2023] [Accepted: 02/14/2023] [Indexed: 06/18/2023]
Abstract
Currently, approximately 8 million adult Americans use electronic cigarettes (e-cigs) daily, including women of childbearing age. It is known that more than 10% of women smoke during their pregnancy, and recent surveys show that rates of maternal vaping are similar to rates of maternal cigarette smoking. However, the effects of inhaling e-cig aerosol on the health of fetuses remain unknown. The objective of the present study was to increase our understanding of the molecular effects caused by in utero exposures to e-cig aerosols on developing mouse lungs and, later in life, on the offspring's susceptibility to developing asthma. METHODS Pregnant mice were exposed throughout gestation to either filtered air or vanilla-flavored e-cig aerosols containing 18 mg/mL of nicotine. Male and female exposed mouse offspring were sacrificed at birth, and then the lung transcriptome was evaluated. Additionally, once sub-groups of male offspring mice reached 4 weeks of age, they were challenged with house dust mites (HDMs) for 3 weeks to assess asthmatic responses. RESULTS The lung transcriptomic responses of the mouse offspring at birth showed that in utero vanilla-flavored e-cig aerosol exposure significantly regulated 88 genes in males (62 genes were up-regulated and 26 genes were down-regulated), and 65 genes were significantly regulated in females (17 genes were up-regulated and 48 genes were down-regulated). Gene network analyses revealed that in utero e-cig aerosol exposure affected canonical pathways associated with CD28 signaling in T helper cells, the role of NFAT in the regulation of immune responses, and phospholipase C signaling in males, whereas the dysregulated genes in the female offspring were associated with NRF2-mediated oxidative stress responses. Moreover, we found that in utero exposures to vanilla-flavored e-cig aerosol exacerbated HDM-induced asthma in 7-week-old male mouse offspring compared to respective in utero air + HDM controls. CONCLUSIONS Overall, these data demonstrate that in utero e-cig aerosol exposure alters the developing mouse lung transcriptome at birth in a sex-specific manner and provide evidence that the inhalation of e-cig aerosols is detrimental to the respiratory health of offspring by increasing the offspring' susceptibility to developing lung diseases later in life.
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Affiliation(s)
- Alexandra Noël
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Sultan Yilmaz
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
| | - Tori Farrow
- Department of Environmental Toxicology, Southern University and A & M College, Baton Rouge, LA 70813, USA
| | | | - Oliver Eickelberg
- Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, University of Pittsburgh, Pittsburgh, PA 15261, USA
| | - Tomislav Jelesijevic
- Department of Comparative Biomedical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA
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14
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Beenken A, Cerutti G, Brasch J, Guo Y, Sheng Z, Erdjument-Bromage H, Aziz Z, Robbins-Juarez SY, Chavez EY, Ahlsen G, Katsamba PS, Neubert TA, Fitzpatrick AWP, Barasch J, Shapiro L. Structures of LRP2 reveal a molecular machine for endocytosis. Cell 2023; 186:821-836.e13. [PMID: 36750096 PMCID: PMC9993842 DOI: 10.1016/j.cell.2023.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2022] [Revised: 11/29/2022] [Accepted: 01/10/2023] [Indexed: 02/08/2023]
Abstract
The low-density lipoprotein (LDL) receptor-related protein 2 (LRP2 or megalin) is representative of the phylogenetically conserved subfamily of giant LDL receptor-related proteins, which function in endocytosis and are implicated in diseases of the kidney and brain. Here, we report high-resolution cryoelectron microscopy structures of LRP2 isolated from mouse kidney, at extracellular and endosomal pH. The structures reveal LRP2 to be a molecular machine that adopts a conformation for ligand binding at the cell surface and for ligand shedding in the endosome. LRP2 forms a homodimer, the conformational transformation of which is governed by pH-sensitive sites at both homodimer and intra-protomer interfaces. A subset of LRP2 deleterious missense variants in humans appears to impair homodimer assembly. These observations lay the foundation for further understanding the function and mechanism of LDL receptors and implicate homodimerization as a conserved feature of the LRP receptor subfamily.
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Affiliation(s)
- Andrew Beenken
- Division of Nephrology, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA
| | - Gabriele Cerutti
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Julia Brasch
- Department of Biochemistry, University of Utah, Salt Lake City, UT 84112, USA
| | - Yicheng Guo
- Aaron Diamond AIDS Research Center, Columbia University, New York, NY 10032, USA
| | - Zizhang Sheng
- Aaron Diamond AIDS Research Center, Columbia University, New York, NY 10032, USA
| | - Hediye Erdjument-Bromage
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Zainab Aziz
- Vagelos College of Physicians and Surgeons, Columbia University, New York, NY 10032, USA
| | | | - Estefania Y Chavez
- Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
| | - Goran Ahlsen
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Phinikoula S Katsamba
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Thomas A Neubert
- Department of Cell Biology, New York University Grossman School of Medicine, New York, NY 10016, USA
| | - Anthony W P Fitzpatrick
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Biochemistry and Molecular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA; Taub Institute for Research on Alzheimer's Disease and the Aging Brain, Columbia University Irving Medical Center, New York, NY 10032, USA.
| | - Jonathan Barasch
- Division of Nephrology, Department of Medicine, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA; Department of Pathology and Cell Biology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA; Columbia University George M. O'Brien Urology Center, New York, NY 10032, USA.
| | - Lawrence Shapiro
- Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Aaron Diamond AIDS Research Center, Columbia University, New York, NY 10032, USA; Department of Biochemistry and Molecular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY 10032, USA.
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15
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LRP2 contributes to planar cell polarity-dependent coordination of motile cilia function. Cell Tissue Res 2023; 392:535-551. [PMID: 36764939 PMCID: PMC10172251 DOI: 10.1007/s00441-023-03757-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 11/04/2022] [Indexed: 02/12/2023]
Abstract
Motile cilia are protruding organelles on specialized epithelia that beat in a synchronous fashion to propel extracellular fluids. Coordination and orientation of cilia beating on individual cells and across tissues is a complex process dependent on planar cell polarity (PCP) signaling. Asymmetric sorting of PCP pathway components, essential to establish planar polarity, involves trafficking along the endocytic path, but the underlying regulatory processes remain incompletely understood. Here, we identified the endocytic receptor LRP2 as regulator of PCP component trafficking in ependyma, a multi-ciliated cell type that is involved in facilitating flow of the cerebrospinal fluid in the brain ventricular system. Lack of receptor expression in gene-targeted mice results in a failure to sort PCP core proteins to the anterior or posterior cell side and, consequently, in the inability to coordinate cilia arrangement and to aligned beating (loss of rotational and translational polarity). LRP2 deficiency coincides with a failure to sort NHERF1, a cytoplasmic LRP2 adaptor to the anterior cell side. As NHERF1 is essential to translocate PCP core protein Vangl2 to the plasma membrane, these data suggest a molecular mechanism whereby LRP2 interacts with PCP components through NHERF1 to control their asymmetric sorting along the endocytic path. Taken together, our findings identified the endocytic receptor LRP2 as a novel regulator of endosomal trafficking of PCP proteins, ensuring their asymmetric partition and establishment of translational and rotational planar cell polarity in the ependyma.
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16
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Li GY, Liu XJ, Fang GQ, Yang J, Zhan S, Li MW. Functional characterization of a low-density lipoprotein receptor in the lepidopteran model, Bombyx mori. INSECT SCIENCE 2022; 29:1262-1274. [PMID: 35411705 DOI: 10.1111/1744-7917.13018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 01/17/2022] [Accepted: 02/02/2022] [Indexed: 06/14/2023]
Abstract
The growth and development of metabolous insects are mainly regulated by ecdysone and juvenile hormone. As a member of the low-density lipoprotein receptor (LDLR) family, megalin (mgl) is involved in the lipoprotein transport of cholesterol which is an essential precursor for the synthesis of ecdysone. Despite extensive studies in mammals, the function of mgl is still largely unknown in insects. In this study, we characterize the function of mgl in the silkworm Bombyx mori, the model species of Lepidoptera. We find that mgl is broadly present in the genomes of lepidopteran species and evolved with divergence between lepidopterans and Drosophila. The expression pattern suggests a ubiquitous role of mgl in the growth and development in the silkworm. We further perform clustered regularly interspaced palindromic repeats (CRISPR) / CRISPR-associated protein 9-based mutagenesis of Bmmgl and find that both the development and the silk production of the silkworm are seriously affected by the disruption of Bmmgl. Our results not only explore the function of mgl in Lepidoptera but also add to our understanding of how cholesterol metabolism is involved in the development of insects.
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Affiliation(s)
- Gui-Yun Li
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Xiao-Jing Liu
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Gang-Qi Fang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Jie Yang
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
- CAS Center for Excellence in Biotic Interactions, University of Chinese Academy of Sciences, Beijing, China
| | - Shuai Zhan
- CAS Key Laboratory of Insect Developmental and Evolutionary Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Mu-Wang Li
- Jiangsu Key Laboratory of Sericultural Biology and Biotechnology, School of Biotechnology, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, China
- The Key Laboratory of Silkworm and Mulberry Genetic Improvement, Ministry of Agriculture, Sericultural Research Institute, Chinese Academy of Agricultural Sciences, Zhenjiang, Jiangsu, China
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17
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Zhang J, Wang Z, Zhang H, Li S, Li J, Liu H, Cheng Q. The role of lipocalin 2 in brain injury and recovery after ischemic and hemorrhagic stroke. Front Mol Neurosci 2022; 15:930526. [PMID: 36187347 PMCID: PMC9520288 DOI: 10.3389/fnmol.2022.930526] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2022] [Accepted: 08/02/2022] [Indexed: 12/03/2022] Open
Abstract
Ischemic and hemorrhagic stroke (including intracerebral hemorrhage, intraventricular hemorrhage, and subarachnoid hemorrhage) is the dominating cause of disability and death worldwide. Neuroinflammation, blood–brain barrier (BBB) disruption, neuronal death are the main pathological progress, which eventually causes brain injury. Increasing evidence indicated that lipocalin 2 (LCN2), a 25k-Da acute phase protein from the lipocalin superfamily, significantly increased immediately after the stroke and played a vital role in these events. Meanwhile, there exists a close relationship between LCN2 levels and the worse clinical outcome of patients with stroke. Further research revealed that LCN2 elimination is associated with reduced immune infiltrates, infarct volume, brain edema, BBB leakage, neuronal death, and neurological deficits. However, some studies revealed that LCN2 might also act as a beneficial factor in ischemic stroke. Nevertheless, the specific mechanism of LCN2 and its primary receptors (24p3R and megalin) involving in brain injury remains unclear. Therefore, it is necessary to investigate the mechanism of LCN2 induced brain damage after stroke. This review focuses on the role of LCN2 and its receptors in brain injury and aiming to find out possible therapeutic targets to reduce brain damage following stroke.
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Affiliation(s)
- Jingwei Zhang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Changsha, China
| | - Zeyu Wang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Changsha, China
| | - Hao Zhang
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Changsha, China
| | - Shuwang Li
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
| | - Jing Li
- Department of Rehabilitation, The Second Xiangya Hospital, Central South University, Changsha, China
| | - Hongwei Liu
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Changsha, China
- Hongwei Liu,
| | - Quan Cheng
- Department of Neurosurgery, Xiangya Hospital, Central South University, Changsha, China
- National Clinical Research Center for Geriatric Disorders, Changsha, China
- Clinical Diagnosis and Therapy Center for Glioma of Xiangya Hospital, Central South University, Changsha, China
- Department of Clinical Pharmacology, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Quan Cheng,
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18
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Megalin and Vitamin D Metabolism—Implications in Non-Renal Tissues and Kidney Disease. Nutrients 2022; 14:nu14183690. [PMID: 36145066 PMCID: PMC9506339 DOI: 10.3390/nu14183690] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/02/2022] [Accepted: 09/06/2022] [Indexed: 11/17/2022] Open
Abstract
Megalin is an endocytic receptor abundantly expressed in proximal tubular epithelial cells and other calciotropic extrarenal cells expressing vitamin D metabolizing enzymes, such as bone and parathyroid cells. The receptor functions in the uptake of the vitamin D-binding protein (DBP) complexed to 25 hydroxyvitamin D3 (25(OH)D3), facilitating the intracellular conversion of precursor 25(OH)D3 to the active 1,25 dihydroxyvitamin D3 (1,25(OH)2D3). The significance of renal megalin-mediated reabsorption of 25(OH)D3 and 1,25(OH)2D3 has been well established experimentally, and other studies have demonstrated relevant roles of extrarenal megalin in regulating vitamin D homeostasis in mammary cells, fat, muscle, bone, and mesenchymal stem cells. Parathyroid gland megalin may regulate calcium signaling, suggesting intriguing possibilities for megalin-mediated cross-talk between calcium and vitamin D regulation in the parathyroid; however, parathyroid megalin functionality has not been assessed in the context of vitamin D. Within various models of chronic kidney disease (CKD), megalin expression appears to be downregulated; however, contradictory results have been observed between human and rodent models. This review aims to provide an overview of the current knowledge of megalin function in the context of vitamin D metabolism, with an emphasis on extrarenal megalin, an area that clearly requires further investigation.
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19
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Elsakka EGE, Mokhtar MM, Hegazy M, Ismail A, Doghish AS. Megalin, a multi-ligand endocytic receptor, and its participation in renal function and diseases: A review. Life Sci 2022; 308:120923. [PMID: 36049529 DOI: 10.1016/j.lfs.2022.120923] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2022] [Revised: 08/13/2022] [Accepted: 08/26/2022] [Indexed: 11/16/2022]
Abstract
The endocytosis mechanism is a complicated system that is essential for cell signaling and survival. Megalin, a membrane-associated endocytic receptor, and its related proteins such as cubilin, the neonatal Fc receptor for IgG, and NaPi-IIa are important in receptors-mediated endocytosis. Physiologically, megalin uptakes plasma vitamins and proteins from primary urine, preventing their loss. It also facilitates tubular retrieval of solutes and endogenous components that may be involved in modulation and recovery from kidney injuries. Moreover, megalin is responsible for endocytosis of xenobiotics and drugs in renal tubules, increasing their half-life and/or their toxicity. Fluctuations in megalin expression and/or functionality due to changes in its regulatory mechanisms are associated with some sort of kidney injury. Also, it's an important component of several pathological conditions, including diabetic nephropathy and Dent disease. Thus, exploring the fundamental role of megalin in the kidney might help in the protection and/or treatment of multiple kidney-related diseases. Hence, this review aimed to explore the physiological roles of megalin in the kidney and their implications for kidney-related injuries.
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Affiliation(s)
- Elsayed G E Elsakka
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt.
| | - Mahmoud Mohamed Mokhtar
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt
| | - Maghawry Hegazy
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt
| | - Ahmed Ismail
- Biochemistry and Molecular Biology Department, Faculty of Pharmacy (Boys), Al-Azhar University, Nasr City 11231, Cairo, Egypt
| | - Ahmed S Doghish
- Department of Biochemistry, Faculty of Pharmacy, Badr University in Cairo (BUC), Badr City, Cairo 11829, Egypt.
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20
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Nguyen TD, Truong ME, Reiter JF. The Intimate Connection Between Lipids and Hedgehog Signaling. Front Cell Dev Biol 2022; 10:876815. [PMID: 35757007 PMCID: PMC9222137 DOI: 10.3389/fcell.2022.876815] [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: 02/15/2022] [Accepted: 05/13/2022] [Indexed: 01/19/2023] Open
Abstract
Hedgehog (HH) signaling is an intercellular communication pathway involved in directing the development and homeostasis of metazoans. HH signaling depends on lipids that covalently modify HH proteins and participate in signal transduction downstream. In many animals, the HH pathway requires the primary cilium, an organelle with a specialized protein and lipid composition. Here, we review the intimate connection between HH signaling and lipids. We highlight how lipids in the primary cilium can create a specialized microenvironment to facilitate signaling, and how HH and components of the HH signal transduction pathway use lipids to communicate between cells.
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Affiliation(s)
- Thi D. Nguyen
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, United States
| | - Melissa E. Truong
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA, United States
| | - Jeremy F. Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, United States,Chan Zuckerberg Biohub, San Francisco, CA, United States,*Correspondence: Jeremy F. Reiter,
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21
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Brain Organization and Human Diseases. Cells 2022; 11:cells11101642. [PMID: 35626679 PMCID: PMC9139716 DOI: 10.3390/cells11101642] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 05/09/2022] [Accepted: 05/12/2022] [Indexed: 02/06/2023] Open
Abstract
The cortex is a highly organized structure that develops from the caudal regions of the segmented neural tube. Its spatial organization sets the stage for future functional arealization. Here, we suggest using a developmental perspective to describe and understand the etiology of common cortical malformations and their manifestation in the human brain.
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22
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Banks WA, Noonan C, Rhea EM, M. Rhea E. Evidence for an alternative insulin transporter at the blood-brain barrier. AGING PATHOBIOLOGY AND THERAPEUTICS 2022; 4:100-108. [PMID: 36644126 PMCID: PMC9837797 DOI: 10.31491/apt.2022.12.100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Accumulating evidence suggests there is an alternative insulin transporter besides the insulin receptor at the blood-brain barrier (BBB), responsible for shuttling insulin from the circulation into the brain. In this review, we summarize key features of the BBB and what makes it unique compared to other capillary beds; summarize what we know about insulin BBB transport; provide an extensive list of diseases, physiological states, and serum factors tested in modifying insulin BBB transport; and lastly, highlight potential alternative transport systems that may be involved in or have already been tested in mediating insulin BBB transport. Identifying the transport system for insulin at the BBB would aide in controlling central nervous system (CNS) insulin levels in multiple diseases and conditions including Alzheimer's disease (AD) and obesity, where availability of insulin to the CNS is limited.
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Affiliation(s)
- William A. Banks
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA 98195, USA.,Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA
| | - Cassidy Noonan
- Research and Development, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA.,University of Washington, Seattle, WA 98195, USA
| | - Elizabeth M. Rhea
- Department of Medicine, Division of Gerontology and Geriatric Medicine, University of Washington, Seattle, WA 98195, USA.,Geriatric Research Education and Clinical Center, Veterans Affairs Puget Sound Health Care System, Seattle, WA 98108, USA.,Corresponding author: Elizabeth M. Rhea, Mailing address: 1660 S. Columbian Way, Seattle, WA 98108, USA.
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23
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Sheikh-Hamad D, Holliday M, Li Q. Megalin-Mediated Trafficking of Mitochondrial Intracrines: Relevance to Signaling and Metabolism. JOURNAL OF CELLULAR IMMUNOLOGY 2021; 3:364-369. [PMID: 35098216 PMCID: PMC8793748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The multi-ligand binding protein megalin (LRP2) is ubiquitously expressed and facilitates cell uptake of hormones, nutrients and vitamins. We have recently shown megalin is present in the mitochondria of cultured epithelial and mesenchymal cells, as well as many organs and tissues. Mitochondrial megalin associates with stanniocalcin-1 and SIRT3; two proteins that promote anti-oxidant defenses. Megalin shuttles mitochondrial intracrines (angiotensin II, stanniocalcin-1 and TGF-β) from the cell surface to the mitochondria through the retrograde early endosome to Golgi pathway and requires Rab32. Deletion of megalin impairs mitochondrial respiration and glycolysis. This pathway overlaps molecular and vesicular trafficking defects common to Donai Barrow and Lowe syndromes, suggesting that mitochondrial intracrine signaling defects may contribute to the pathogenesis of these diseases.
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Affiliation(s)
- David Sheikh-Hamad
- Division of Nephrology and Selzman Institute for Kidney Health, Department of Medicine, Baylor College of Medicine, Houston, Texas, 77030 USA,Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. Debakey VAMC, Houston, Texas, 77030 USA,Correspondence should be addressed to David Sheikh-Hamad;
| | - Michael Holliday
- Division of Nephrology and Selzman Institute for Kidney Health, Department of Medicine, Baylor College of Medicine, Houston, Texas, 77030 USA,Center for Translational Research on Inflammatory Diseases (CTRID), Michael E. Debakey VAMC, Houston, Texas, 77030 USA
| | - Qingtian Li
- Division of Nephrology and Selzman Institute for Kidney Health, Department of Medicine, Baylor College of Medicine, Houston, Texas, 77030 USA
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24
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Bai Y, Dong X, Li M, Hei N, Ge C, Li M, Yin P, Zhang L. Pathological Characteristics of Malformations of Cortical Development in Golden Syrian Hamsters with LDLR Deficiency. J Neuropathol Exp Neurol 2021; 80:1143-1146. [PMID: 34718658 DOI: 10.1093/jnen/nlab103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Yun Bai
- Department of Pathology, Hebei Medical University, Shijiazhuang, Hebei, China.,Hebei Key Laboratory of Environment and Human Health, Shijiazhuang, Hebei, China
| | - Xiaohui Dong
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Mingzhao Li
- Department of Pathology, Hebei Medical University, Shijiazhuang, Hebei, China
| | - Naiheng Hei
- Hebei Key Laboratory of Environment and Human Health, Shijiazhuang, Hebei, China.,The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Chen Ge
- Department of Pathology, Hebei Medical University, Shijiazhuang, Hebei, China.,Hebei Key Laboratory of Environment and Human Health, Shijiazhuang, Hebei, China
| | - Mei Li
- The Fourth Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Pengfei Yin
- Hebei INVIVO Biotechnology Co., Ltd., Shijiazhuang, Hebei, China
| | - Lianshan Zhang
- Department of Pathology, Hebei Medical University, Shijiazhuang, Hebei, China.,Hebei Key Laboratory of Environment and Human Health, Shijiazhuang, Hebei, China
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25
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Hoffmann N, Peters J. Functions of the (pro)renin receptor (Atp6ap2) at molecular and system levels: pathological implications in hypertension, renal and brain development, inflammation, and fibrosis. Pharmacol Res 2021; 173:105922. [PMID: 34607004 DOI: 10.1016/j.phrs.2021.105922] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2021] [Revised: 09/16/2021] [Accepted: 09/29/2021] [Indexed: 12/13/2022]
Abstract
The (pro)renin receptor [(P)RR, Atp6ap2] was initially discovered as a membrane-bound binding partner of prorenin and renin. A soluble (P)RR has additional paracrine effects and is involved in metabolic syndrome and kidney damage. Meanwhile it is clear that most of the effects of the (P)RR are independent of prorenin. In the kidney, (P)RR plays an important role in renal dysfunction by activating proinflammatory and profibrotic molecules. In the brain, (P)RR is expressed in cardiovascular regulatory nuclei and is linked to hypertension. (P)RR is known to be an essential component of the v-ATPase as a key accessory protein and plays an important role in kidney, brain and heart via regulating the pH of the extracellular space and intracellular compartments. V-ATPase and (P)RR together act on WNT and mTOR signalling pathways, which are responsible for cellular homeostasis and autophagy. (P)RR through its role in v-ATPase assembly and function is also important for fast recycling endocytosis by megalin. In the kidney, megalin together with v-ATPase and (P)RR is crucial for endocytic uptake of components of the RAS and their intracellular processing. In the brain, (P)RR, v-ATPases and megalin are important regulators both during development and in the adult. All three proteins are associated with diseases such as XLMR, XMRE, X-linked parkinsonism and epilepsy, cognitive disorders with Parkinsonism, spasticity, intellectual disability, and Alzheimer's Disease which are characterized by impaired neuronal function and/or neuronal loss. The present review focusses on the relevant effects of Atp6ap2 without assigning them necessarily to the RAS. Mechanistically, many effects can be well explained by the role of Atp6ap2 for v-ATPase assembly and function. Furthermore, application of a soluble (P)RR analogue as new therapeutic option is discussed.
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Affiliation(s)
- Nadin Hoffmann
- Institute of Physiology, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15A, 17475, Greifswald, Germany
| | - Jörg Peters
- Institute of Physiology, University Medicine Greifswald, Friedrich-Ludwig-Jahn-Str. 15A, 17475, Greifswald, Germany.
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26
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Olson B, Zhu X, Norgard MA, Diba P, Levasseur PR, Buenafe AC, Huisman C, Burfeind KG, Michaelis KA, Kong G, Braun T, Marks DL. Chronic cerebral lipocalin 2 exposure elicits hippocampal neuronal dysfunction and cognitive impairment. Brain Behav Immun 2021; 97:102-118. [PMID: 34245812 PMCID: PMC8453133 DOI: 10.1016/j.bbi.2021.07.002] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2021] [Revised: 06/21/2021] [Accepted: 07/03/2021] [Indexed: 12/12/2022] Open
Abstract
Lipocalin 2 (LCN2) is a pleiotropic molecule that is induced in the central nervous system (CNS) in several acute and chronic pathologies. The acute induction of LCN2 evolved as a beneficial process, aimed at combating bacterial infection through the sequestration of iron from pathogens, while the role of LCN2 during chronic, non-infectious disease remains unclear, and recent studies suggest that LCN2 is neurotoxic. However, whether LCN2 is sufficient to induce behavioral and cognitive alterations remains unclear. In this paper, we sought to address the role of cerebral LCN2 on cognition in both acute and chronic settings. We demonstrate that LCN2 is robustly induced in the CNS during both acute and chronic inflammatory conditions, including LPS-based sepsis and cancer cachexia. In vivo, LPS challenge results in a global induction of LCN2 in the central nervous system, while cancer cachexia results in a distribution specific to the vasculature. Similar to these in vivo observations, in vitro modeling demonstrated that both glia and cerebral endothelium produce and secrete LCN2 when challenged with LPS, while only cerebral endothelium secrete LCN2 when challenged with cancer-conditioned medium. Chronic, but not short-term, cerebral LCN2 exposure resulted in reduced hippocampal neuron staining intensity, an increase in newborn neurons, microglial activation, and increased CNS immune cell infiltration, while gene set analyses suggested these effects were mediated through melanocortin-4 receptor independent mechanisms. RNA sequencing analyses of primary hippocampal neurons revealed a distinct transcriptome associated with prolonged LCN2 exposure, and ontology analysis was suggestive of altered neurite growth and abnormal spatial learning. Indeed, LCN2-treated hippocampal neurons display blunted neurite processes, and mice exposed to prolonged cerebral LCN2 levels experienced a reduction in spatial reference memory as indicated by Y-maze assessment. These findings implicate LCN2 as a pathologic mediator of cognitive decline in the setting of chronic disease.
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Affiliation(s)
- Brennan Olson
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, OR USA, Medical Scientist Training Program, Oregon Health & Science University, Portland, OR USA
| | - Xinxia Zhu
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, OR USA
| | - Mason A Norgard
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, OR USA
| | - Parham Diba
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, OR USA, Medical Scientist Training Program, Oregon Health & Science University, Portland, OR USA
| | - Peter R Levasseur
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, OR USA
| | - Abby C Buenafe
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, OR USA
| | - Christian Huisman
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, OR USA
| | - Kevin G Burfeind
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, OR USA, Medical Scientist Training Program, Oregon Health & Science University, Portland, OR USA
| | - Katherine A Michaelis
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, OR USA, Medical Scientist Training Program, Oregon Health & Science University, Portland, OR USA
| | - Garth Kong
- Knight Cancer Institute, Oregon Health & Science University, Portland, OR USA
| | - Theodore Braun
- Knight Cancer Institute, Oregon Health & Science University, Portland, OR USA
| | - Daniel L Marks
- Papé Family Pediatric Research Institute, Oregon Health & Science University, Portland, OR, USA; Brenden-Colson Center for Pancreatic Care, Oregon Health and & Science University Portland, OR, USA; Knight Cancer Institute, Oregon Health & Science University, Portland, OR, USA.
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27
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Mecklenburg N, Kowalczyk I, Witte F, Görne J, Laier A, Mamo TM, Gonschior H, Lehmann M, Richter M, Sporbert A, Purfürst B, Hübner N, Hammes A. Identification of disease-relevant modulators of the SHH pathway in the developing brain. Development 2021; 148:272000. [PMID: 34463328 DOI: 10.1242/dev.199307] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Accepted: 07/19/2021] [Indexed: 12/13/2022]
Abstract
Pathogenic gene variants in humans that affect the sonic hedgehog (SHH) pathway lead to severe brain malformations with variable penetrance due to unknown modifier genes. To identify such modifiers, we established novel congenic mouse models. LRP2-deficient C57BL/6N mice suffer from heart outflow tract defects and holoprosencephaly caused by impaired SHH activity. These defects are fully rescued on a FVB/N background, indicating a strong influence of modifier genes. Applying comparative transcriptomics, we identified Pttg1 and Ulk4 as candidate modifiers upregulated in the rescue strain. Functional analyses showed that ULK4 and PTTG1, both microtubule-associated proteins, are positive regulators of SHH signaling, rendering the pathway more resilient to disturbances. In addition, we characterized ULK4 and PTTG1 as previously unidentified components of primary cilia in the neuroepithelium. The identification of genes that powerfully modulate the penetrance of genetic disturbances affecting the brain and heart is likely relevant to understanding the variability in human congenital disorders.
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Affiliation(s)
- Nora Mecklenburg
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Izabela Kowalczyk
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Franziska Witte
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Jessica Görne
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Alena Laier
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Tamrat M Mamo
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Hannes Gonschior
- Cellular Imaging, Light Microscopy, Leibniz-Research Institute for Molecular Pharmacology (FMP), 13125 Berlin, Germany
| | - Martin Lehmann
- Cellular Imaging, Light Microscopy, Leibniz-Research Institute for Molecular Pharmacology (FMP), 13125 Berlin, Germany
| | - Matthias Richter
- Advanced Light Microscopy Technology Platform, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Anje Sporbert
- Advanced Light Microscopy Technology Platform, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Bettina Purfürst
- Electron microscopy technology platform, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
| | - Norbert Hübner
- Cardiovascular and Metabolic Sciences, Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Berlin, 10785 Berlin, Germany.,Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany.,Berlin Institute of Health (BIH), 10178 Berlin, Germany
| | - Annette Hammes
- Disorders of the Nervous System, Max-Delbrück-Center for Molecular Medicine in the Helmholtz Association (MDC), 13125 Berlin, Germany
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28
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Arrigo AB, Lin JHI. Endocytic Protein Defects in the Neural Crest Cell Lineage and Its Pathway Are Associated with Congenital Heart Defects. Int J Mol Sci 2021; 22:ijms22168816. [PMID: 34445520 PMCID: PMC8396181 DOI: 10.3390/ijms22168816] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 08/09/2021] [Accepted: 08/10/2021] [Indexed: 02/02/2023] Open
Abstract
Endocytic trafficking is an under-appreciated pathway in cardiac development. Several genes related to endocytic trafficking have been uncovered in a mutagenic ENU screen, in which mutations led to congenital heart defects (CHDs). In this article, we review the relationship between these genes (including LRP1 and LRP2) and cardiac neural crest cells (CNCCs) during cardiac development. Mice with an ENU-induced Lrp1 mutation exhibit a spectrum of CHDs. Conditional deletion using a floxed Lrp1 allele with different Cre drivers showed that targeting neural crest cells with Wnt1-Cre expression replicated the full cardiac phenotypes of the ENU-induced Lrp1 mutation. In addition, LRP1 function in CNCCs is required for normal OFT lengthening and survival/expansion of the cushion mesenchyme, with other cell lineages along the NCC migratory path playing an additional role. Mice with an ENU-induced and targeted Lrp2 mutation demonstrated the cardiac phenotype of common arterial trunk (CAT). Although there is no impact on CNCCs in Lrp2 mutants, the loss of LRP2 results in the depletion of sonic hedgehog (SHH)-dependent cells in the second heart field. SHH is known to be crucial for CNCC survival and proliferation, which suggests LRP2 has a non-autonomous role in CNCCs. In this article, other endocytic trafficking proteins that are associated with CHDs that may play roles in the NCC pathway during development, such as AP1B1, AP2B1, FUZ, MYH10, and HECTD1, are reviewed.
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Affiliation(s)
- Angelo B. Arrigo
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, PA 15224, USA;
| | - Jiuann-Huey Ivy Lin
- Department of Developmental Biology, University of Pittsburgh, Pittsburgh, PA 15224, USA;
- Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA 15224, USA
- Correspondence: ; Tel.: +1-412-692-7366; Fax: +1-412-692-5169
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29
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Kim JH, Barbagallo B, Annunziato K, Farias-Pereira R, Doherty JJ, Lee J, Zina J, Tindal C, McVey C, Aresco R, Johnstone M, Sant KE, Timme-Laragy A, Park Y, Clark JM. Maternal preconception PFOS exposure of Drosophila melanogaster alters reproductive capacity, development, morphology and nutrient regulation. Food Chem Toxicol 2021; 151:112153. [PMID: 33774094 DOI: 10.1016/j.fct.2021.112153] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2020] [Revised: 03/17/2021] [Accepted: 03/19/2021] [Indexed: 10/21/2022]
Abstract
Perfluorooctanesulfonic acid (PFOS) is a persistent synthetic surfactant widely detected in the environment. Developmental PFOS exposures are associated with low birth weight and chronic exposures increase risk for obesity and type 2 diabetes. As an obesogen, PFOS poses a major public health exposure risk and much remains to be understood about the critical windows of exposure and mechanisms impacted, especially during preconception. Here, we leverage evolutionarily conserved pathways and processes in the fruit fly Drosophila melanogaster (wild-type Canton-S and megalin-UAS RNAi transgenic fly lines) to investigate the window of maternal preconception exposure to PFOS on reproductive and developmental toxicity, and examine receptor (megalin)-mediated endocytosis of nutrients and PFOS into the oocyte as a potential mechanism. Preconception exposure to 2 ng PFOS/female resulted in an internal concentration of 0.081 ng/fly over two days post exposure, no mortality and reduced megalin transcription. The number of eggs laid 1-3 days post exposure was reduced and contained 0.018 ng PFOS/egg. Following heat shock, PFOS was significantly reduced in eggs from megalin-knockdown transgenic females. Cholesterol and triglycerides were increased in eggs laid immediately following PFOS exposure by non-heat shocked transgenic females whereas decreased cholesterol and increased protein levels were found in eggs laid by heat shocked transgenic females. Preconception exposure likewise increased cholesterol in early emerging wildtype F1 adults and also resulted in progeny with a substantial developmental delay, a reduction in adult weights, and altered transcription of Drosophila insulin-like peptide genes. These findings support an interaction between PFOS and megalin that interferes with normal nutrient transport during oocyte maturation and embryogenesis, which may be associated with later in life developmental delay and reduced weight.
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Affiliation(s)
- Ju Hyeon Kim
- Department of Veterinary & Animal Sciences, University of Massachusetts, Amherst, MA, USA
| | - Belinda Barbagallo
- Department of Biology & Biomedical Sciences, Salve Regina University, Newport, RI, USA
| | - Kate Annunziato
- Department of Environmental Health Sciences, University of Massachusetts, Amherst, MA, USA
| | | | - Jeffery J Doherty
- Department of Veterinary & Animal Sciences, University of Massachusetts, Amherst, MA, USA
| | - Jonghwa Lee
- Department of Veterinary & Animal Sciences, University of Massachusetts, Amherst, MA, USA
| | - Jake Zina
- Department of Veterinary & Animal Sciences, University of Massachusetts, Amherst, MA, USA
| | - Cole Tindal
- Department of Biology & Biomedical Sciences, Salve Regina University, Newport, RI, USA
| | - Cailin McVey
- Department of Biology & Biomedical Sciences, Salve Regina University, Newport, RI, USA
| | - Racheal Aresco
- Department of Biology & Biomedical Sciences, Salve Regina University, Newport, RI, USA
| | - Megan Johnstone
- Department of Biology & Biomedical Sciences, Salve Regina University, Newport, RI, USA
| | - Karilyn E Sant
- Department of Environmental Health Sciences, University of Massachusetts, Amherst, MA, USA; Division of Environmental Health, School of Public Health, San Diego State University, San Diego, CA, USA
| | - Alicia Timme-Laragy
- Department of Environmental Health Sciences, University of Massachusetts, Amherst, MA, USA
| | - Yeonhwa Park
- Department of Food Science, University of Massachusetts, Amherst, MA, USA
| | - John M Clark
- Department of Veterinary & Animal Sciences, University of Massachusetts, Amherst, MA, USA.
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30
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Kowalczyk I, Lee C, Schuster E, Hoeren J, Trivigno V, Riedel L, Görne J, Wallingford JB, Hammes A, Feistel K. Neural tube closure requires the endocytic receptor Lrp2 and its functional interaction with intracellular scaffolds. Development 2021; 148:dev195008. [PMID: 33500317 PMCID: PMC7860117 DOI: 10.1242/dev.195008] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Accepted: 12/11/2020] [Indexed: 12/20/2022]
Abstract
Pathogenic mutations in the endocytic receptor LRP2 in humans are associated with severe neural tube closure defects (NTDs) such as anencephaly and spina bifida. Here, we have combined analysis of neural tube closure in mouse and in the African Clawed Frog Xenopus laevis to elucidate the etiology of Lrp2-related NTDs. Lrp2 loss of function impaired neuroepithelial morphogenesis, culminating in NTDs that impeded anterior neural plate folding and neural tube closure in both model organisms. Loss of Lrp2 severely affected apical constriction as well as proper localization of the core planar cell polarity (PCP) protein Vangl2, demonstrating a highly conserved role of the receptor in these processes, which are essential for neural tube formation. In addition, we identified a novel functional interaction of Lrp2 with the intracellular adaptor proteins Shroom3 and Gipc1 in the developing forebrain. Our data suggest that, during neurulation, motifs within the intracellular domain of Lrp2 function as a hub that orchestrates endocytic membrane removal for efficient apical constriction, as well as PCP component trafficking in a temporospatial manner.
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Affiliation(s)
- Izabela Kowalczyk
- Disorders of the Nervous System, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Robert Rössle Strasse 10, 13125 Berlin, Germany
| | - Chanjae Lee
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Elisabeth Schuster
- University of Hohenheim, Institute of Biology, Department of Zoology, Garbenstrasse 30, 70599 Stuttgart, Germany
| | - Josefine Hoeren
- University of Hohenheim, Institute of Biology, Department of Zoology, Garbenstrasse 30, 70599 Stuttgart, Germany
| | - Valentina Trivigno
- University of Hohenheim, Institute of Biology, Department of Zoology, Garbenstrasse 30, 70599 Stuttgart, Germany
| | - Levin Riedel
- Disorders of the Nervous System, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Robert Rössle Strasse 10, 13125 Berlin, Germany
| | - Jessica Görne
- Disorders of the Nervous System, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Robert Rössle Strasse 10, 13125 Berlin, Germany
| | - John B Wallingford
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, TX 78712, USA
| | - Annette Hammes
- Disorders of the Nervous System, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Robert Rössle Strasse 10, 13125 Berlin, Germany
| | - Kerstin Feistel
- University of Hohenheim, Institute of Biology, Department of Zoology, Garbenstrasse 30, 70599 Stuttgart, Germany
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31
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Puthanveetil P, Kong X, Bräse S, Voros G, Peer WA. Transcriptome analysis of two structurally related flavonoids; Apigenin and Chrysin revealed hypocholesterolemic and ketogenic effects in mouse embryonic fibroblasts. Eur J Pharmacol 2020; 893:173804. [PMID: 33347826 DOI: 10.1016/j.ejphar.2020.173804] [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: 09/29/2020] [Revised: 12/02/2020] [Accepted: 12/10/2020] [Indexed: 12/14/2022]
Abstract
There is no known single therapeutic drug for treating hypercholesterolemia that comes with negligible systemic side effects. In the current study, using next generation RNA sequencing approach in mouse embryonic fibroblasts we discovered that two structurally related flavonoid compounds. Apigenin and Chrysin exhibited moderate blocking ability of multiple transcripts that regulate rate limiting enzymes in the cholesterol biosynthesis pathway. The observed decrease in cholesterol biosynthesis pathway correlated well with an increase in transcripts involved in generation and trafficking of ketone bodies as evident by the upregulation of Bdh1 and Slc16a6 transcripts. The hypocholesterolemic potential of Apigenin and Chrysin at higher concentrations along with their ability to generate ketogenic substrate especially during embryonic stage is useful or detrimental for embryonic health is not clear and still debatable. Our study will serve as a steppingstone to further the investigation in whole animal studies and also in translating this knowledge to human studies.
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Affiliation(s)
- Prasanth Puthanveetil
- Department of Pharmacology, College of Graduate Studies, Midwestern University, Downers Grove, IL, USA.
| | - Xiaoli Kong
- Department of Mathematics and Statistics, Loyola University Chicago, Chicago, IL, USA.
| | - Stefan Bräse
- Institute of Biological and Chemical Systems (IBCS), Karlsruhe Institute of Technology (KIT), Hermann von Helmholtz Platz 1, 76344, Eggenstein Leopoldshafen, Germany.
| | - Gabor Voros
- Department of Cardiovascular Diseases, University Hospital Gasthuisberg, Catholic University Leuven, Herestraat 49, 3000, Leuven, Belgium.
| | - Wendy Ann Peer
- Department of Environmental Science and Technology, College of Agricultural and Natural Resources, University of Maryland, MD, USA.
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32
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Christ A, Marczenke M, Willnow TE. LRP2 controls sonic hedgehog-dependent differentiation of cardiac progenitor cells during outflow tract formation. Hum Mol Genet 2020; 29:3183-3196. [PMID: 32901292 PMCID: PMC7689296 DOI: 10.1093/hmg/ddaa200] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/21/2020] [Accepted: 08/24/2020] [Indexed: 12/15/2022] Open
Abstract
Conotruncal malformations are a major cause of congenital heart defects in newborn infants. Recently, genetic screens in humans and in mouse models have identified mutations in LRP2, a multi-ligand receptor, as a novel cause of a common arterial trunk, a severe form of outflow tract (OFT) defect. Yet, the underlying mechanism why the morphogen receptor LRP2 is essential for OFT development remained unexplained. Studying LRP2-deficient mouse models, we now show that LRP2 is expressed in the cardiac progenitor niche of the anterior second heart field (SHF) that contributes to the elongation of the OFT during separation into aorta and pulmonary trunk. Loss of LRP2 in mutant mice results in the depletion of a pool of sonic hedgehog-dependent progenitor cells in the anterior SHF due to premature differentiation into cardiomyocytes as they migrate into the OFT myocardium. Depletion of this cardiac progenitor cell pool results in aberrant shortening of the OFT, the likely cause of CAT formation in affected mice. Our findings identified the molecular mechanism whereby LRP2 controls the maintenance of progenitor cell fate in the anterior SHF essential for OFT separation, and why receptor dysfunction is a novel cause of conotruncal malformation.
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Affiliation(s)
- Annabel Christ
- Max-Delbrueck-Center for Molecular Medicine, 13125 Berlin, Germany
| | - Maike Marczenke
- Max-Delbrueck-Center for Molecular Medicine, 13125 Berlin, Germany
| | - Thomas E Willnow
- Max-Delbrueck-Center for Molecular Medicine, 13125 Berlin, Germany
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33
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Charlton JR, Tan W, Daouk G, Teot L, Rosen S, Bennett KM, Cwiek A, Nam S, Emma F, Jouret F, Oliveira JP, Tranebjærg L, Frykholm C, Mane S, Hildebrandt F, Srivastava T, Storm T, Christensen EI, Nielsen R. Beyond the tubule: pathological variants of LRP2, encoding the megalin receptor, result in glomerular loss and early progressive chronic kidney disease. Am J Physiol Renal Physiol 2020; 319:F988-F999. [PMID: 33103447 DOI: 10.1152/ajprenal.00295.2020] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Pathogenic variants in the LRP2 gene, encoding the multiligand receptor megalin, cause a rare autosomal recessive syndrome: Donnai-Barrow/Facio-Oculo-Acoustico-Renal (DB/FOAR) syndrome. Because of the rarity of the syndrome, the long-term consequences of the tubulopathy on human renal health have been difficult to ascertain, and the human clinical condition has hitherto been characterized as a benign tubular condition with asymptomatic low-molecular-weight proteinuria. We investigated renal function and morphology in a murine model of DB/FOAR syndrome and in patients with DB/FOAR. We analyzed glomerular filtration rate in mice by FITC-inulin clearance and clinically characterized six families, including nine patients with DB/FOAR and nine family members. Urine samples from patients were analyzed by Western blot analysis and biopsy materials were analyzed by histology. In the mouse model, we used histological methods to assess nephrogenesis and postnatal renal structure and contrast-enhanced magnetic resonance imaging to assess glomerular number. In megalin-deficient mice, we found a lower glomerular filtration rate and an increase in the abundance of injury markers, such as kidney injury molecule-1 and N-acetyl-β-d-glucosaminidase. Renal injury was validated in patients, who presented with increased urinary kidney injury molecule-1, classical markers of chronic kidney disease, and glomerular proteinuria early in life. Megalin-deficient mice had normal nephrogenesis, but they had 19% fewer nephrons in early adulthood and an increased fraction of nephrons with disconnected glomerulotubular junction. In conclusion, megalin dysfunction, as present in DB/FOAR syndrome, confers an increased risk of progression into chronic kidney disease.
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Affiliation(s)
- Jennifer R Charlton
- Division of Nephrology, Department of Pediatrics, University of Virginia, Charlottesville, Virginia
| | - Weizhen Tan
- Division of Nephrology, Massachusetts General Hospital for Children, Boston, Massachusetts
| | - Ghaleb Daouk
- Division of Nephrology, Massachusetts General Hospital for Children, Boston, Massachusetts
| | - Lisa Teot
- Department of Pathology, Boston Children's Hospital, Boston, Massachusetts
| | - Seymour Rosen
- Department of Pathology, Boston Children's Hospital, Boston, Massachusetts.,Department of Pathology, Beth Israel Deaconess Medical Center, Boston, Massachusetts
| | - Kevin M Bennett
- Department of Radiology, Washington University in Saint Louis, St. Louis, Missouri
| | - Aleksandra Cwiek
- Division of Nephrology, Department of Pediatrics, University of Virginia, Charlottesville, Virginia
| | - Sejin Nam
- Department of Physics, University of Hawai'i at Manoa, Manoa, Hawai'i
| | - Francesco Emma
- Division of Nephrology, Department of Pediatric Subspecialties, Bambino Gesù Children's Hospital- Istituto di Ricovero e Cura a Carattere Scientifico, Rome, Italy
| | - François Jouret
- Groupe Interdisciplinaire de Génoprotéomique Appliquée, Unit of Cardiovascular Sciences, University of Liège, Liège, Belgium
| | - João Paulo Oliveira
- Service of Medical Genetics, São João University Hospital Centre and Faculty of Medicine, University of Porto and i3S-Institute for Health Research and Innovation, Porto, Portugal
| | - Lisbeth Tranebjærg
- Department of Clinical Genetics, Rigshospitalet/The Kennedy Centre, Copenhagen, Denmark.,Institute of Clinical Medicine, University of Copenhagen, The Panum Institute, Copenhagen, Denmark
| | - Carina Frykholm
- Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Shrikant Mane
- Department of Genetics, Yale University School of Medicine, New Haven, Connecticut
| | - Friedhelm Hildebrandt
- Department of Medicine, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts
| | | | - Tina Storm
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
| | | | - Rikke Nielsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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34
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Rezaee MS, Liebhart D, Hess C, Hess M, Paudel S. Bacterial Infection in Chicken Embryos and Consequences of Yolk Sac Constitution for Embryo Survival. Vet Pathol 2020; 58:71-79. [PMID: 33016240 DOI: 10.1177/0300985820960127] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Bacterial infections in chicken eggs often cause mortality of embryos and clinical consequences in chicks but the pathological mechanism is unclear. We investigated the pathological changes and bacterial growth kinetics in dead and live embryos following infection with 2 Escherichia coli strains with a different clinical background and with 1 Salmonella Enteritidis strain. In 2 experiments, 12-day-old embryos were infected via the allantoic sac with 100 µl of 1 to 5 × 102 CFU/ml of one of the bacteria. In experiment 1, only dead embryos were sampled until 4 days postinfection (dpi), and surviving embryos were sampled at 5 dpi. In experiment 2, sampling was performed in dead and killed embryos sequentially at 1, 2, 3, and 4 dpi. The bacteria showed varying pathogenicity in embryos. The yolk sacs of dead embryos showed congestion, inflammation, damaged blood vessels, and abnormal endodermal epithelial cells. Such lesions were absent in the yolk sacs of negative control embryos and in those of embryos that survived infection. The livers and hearts of dead embryos showed congestion and lysed erythrocytes with no morphological changes in hepatocytes or myocardial cells. All bacteria multiplied rapidly in the yolks of infected embryos, although this did not predict survival. However, the livers of dead embryos contained significantly higher bacterial loads than the livers of the embryos that survived infection. The results provide evidence that lesions in the yolk sac, which have been neglected to date, coincide with embryonic mortality, underlining the importance of healthy yolk sacs for embryo survival.
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Affiliation(s)
| | | | - Claudia Hess
- 27260University of Veterinary Medicine, Vienna, Austria
| | - Michael Hess
- 27260University of Veterinary Medicine, Vienna, Austria
| | - Surya Paudel
- 27260University of Veterinary Medicine, Vienna, Austria
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35
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Metabolic Health in Obese Subjects-Is There a Link to Lactoferrin and Lactoferrin Receptor-Related Gene Polymorphisms? Nutrients 2020; 12:nu12092843. [PMID: 32957486 PMCID: PMC7551427 DOI: 10.3390/nu12092843] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2020] [Revised: 08/25/2020] [Accepted: 09/15/2020] [Indexed: 12/21/2022] Open
Abstract
This study aimed to evaluate the association of genetic variants in lactoferrin (LTF) metabolism-related genes with the prevalence of metabolically healthy obesity (MHO) and metabolically unhealthy obesity (MUHO). In total, 161 MHO and 291 MUHO subjects were recruited to the study. The following polymorphisms were genotyped: low-density lipoprotein receptor-related protein (LRP) 2 rs2544390, LRP1 rs4759277, LRP1 rs1799986, LTF rs1126477, LTF rs2239692 and LTF rs1126478. We found significant differences in the genotype frequencies of LTF rs2239692 between MHO and MUHO subjects, with the CT variant associated with lower odds of developing metabolic syndrome than the TT variant. In the total population, significant differences in body weight and waist circumference (WC) were identified between LTF rs1126477 gene variants. A similar association with WC was observed in MUHO subjects, while significant differences in body mass index and low-density lipoprotein cholesterol levels were discovered between LTF rs1126477 gene variants in MHO subjects. Besides, there were significant differences in diastolic blood pressure between LRP1 rs1799986 gene variants in MUHO subjects, as well as in WC and high-density lipoprotein cholesterol levels between LRP1 rs4759277 gene variants in MHO subjects. In conclusion, selected lactoferrin and lactoferrin receptor-related gene variants may be associated with the prevalence of metabolically healthy or metabolically unhealthy obesity.
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36
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Hong M, Christ A, Christa A, Willnow TE, Krauss RS. Cdon mutation and fetal alcohol converge on Nodal signaling in a mouse model of holoprosencephaly. eLife 2020; 9:60351. [PMID: 32876567 PMCID: PMC7467722 DOI: 10.7554/elife.60351] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 08/10/2020] [Indexed: 02/07/2023] Open
Abstract
Holoprosencephaly (HPE), a defect in midline patterning of the forebrain and midface, arises ~1 in 250 conceptions. It is associated with predisposing mutations in the Nodal and Hedgehog (HH) pathways, with penetrance and expressivity graded by genetic and environmental modifiers, via poorly understood mechanisms. CDON is a multifunctional co-receptor, including for the HH pathway. In mice, Cdon mutation synergizes with fetal alcohol exposure, producing HPE phenotypes closely resembling those seen in humans. We report here that, unexpectedly, Nodal signaling is a major point of synergistic interaction between Cdon mutation and fetal alcohol. Window-of-sensitivity, genetic, and in vitro findings are consistent with a model whereby brief exposure of Cdon mutant embryos to ethanol during gastrulation transiently and partially inhibits Nodal pathway activity, with consequent effects on midline patterning. These results illuminate mechanisms of gene-environment interaction in a multifactorial model of a common birth defect.
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Affiliation(s)
- Mingi Hong
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Annabel Christ
- Max-Delbruck-Center for Molecular Medicine, Berlin, Germany
| | - Anna Christa
- Max-Delbruck-Center for Molecular Medicine, Berlin, Germany
| | | | - Robert S Krauss
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, United States
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37
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Gomes JR, Lobo A, Nogueira R, Terceiro AF, Costelha S, Lopes IM, Magalhães A, Summavielle T, Saraiva MJ. Neuronal megalin mediates synaptic plasticity-a novel mechanism underlying intellectual disabilities in megalin gene pathologies. Brain Commun 2020; 2:fcaa135. [PMID: 33225275 PMCID: PMC7667529 DOI: 10.1093/braincomms/fcaa135] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Revised: 07/14/2020] [Accepted: 07/16/2020] [Indexed: 12/15/2022] Open
Abstract
Donnai-Barrow syndrome, a genetic disorder associated to LRP2 (low-density lipoprotein receptor 2/megalin) mutations, is characterized by unexplained neurological symptoms and intellectual deficits. Megalin is a multifunctional endocytic clearance cell-surface receptor, mostly described in epithelial cells. This receptor is also expressed in the CNS, mainly in neurons, being involved in neurite outgrowth and neuroprotective mechanisms. Yet, the mechanisms involved in the regulation of megalin in the CNS are poorly understood. Using transthyretin knockout mice, a megalin ligand, we found that transthyretin positively regulates neuronal megalin levels in different CNS areas, particularly in the hippocampus. Transthyretin is even able to rescue megalin downregulation in transthyretin knockout hippocampal neuronal cultures, in a positive feedback mechanism via megalin. Importantly, transthyretin activates a regulated intracellular proteolysis mechanism of neuronal megalin, producing an intracellular domain, which is translocated to the nucleus, unveiling megalin C-terminal as a potential transcription factor, able to regulate gene expression. We unveil that neuronal megalin reduction affects physiological neuronal activity, leading to decreased neurite number, length and branching, and increasing neuronal susceptibility to a toxic insult. Finally, we unravel a new unexpected role of megalin in synaptic plasticity, by promoting the formation and maturation of dendritic spines, and contributing for the establishment of active synapses, both in in vitro and in vivo hippocampal neurons. Moreover, these structural and synaptic roles of megalin impact on learning and memory mechanisms, since megalin heterozygous mice show hippocampal-related memory and learning deficits in several behaviour tests. Altogether, we unveil a complete novel role of megalin in the physiological neuronal activity, mainly in synaptic plasticity with impact in learning and memory. Importantly, we contribute to disclose the molecular mechanisms underlying the cognitive and intellectual disabilities related to megalin gene pathologies.
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Affiliation(s)
- João R Gomes
- Molecular Neurobiology Unit, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal.,I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Andrea Lobo
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.,Addiction Biology Group, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal
| | - Renata Nogueira
- Molecular Neurobiology Unit, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal.,I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Ana F Terceiro
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.,Addiction Biology Group, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal
| | - Susete Costelha
- Molecular Neurobiology Unit, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal.,I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Igor M Lopes
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.,Addiction Biology Group, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal
| | - Ana Magalhães
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.,Addiction Biology Group, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal
| | - Teresa Summavielle
- I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal.,Addiction Biology Group, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal
| | - Maria J Saraiva
- Molecular Neurobiology Unit, IBMC- Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal.,I3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
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38
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Bartolome F, Antequera D, de la Cueva M, Rubio-Fernandez M, Castro N, Pascual C, Camins A, Carro E. Endothelial-specific deficiency of megalin in the brain protects mice against high-fat diet challenge. J Neuroinflammation 2020; 17:22. [PMID: 31937343 PMCID: PMC6961312 DOI: 10.1186/s12974-020-1702-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 01/06/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND The increasing risk of obesity and diabetes among other metabolic disorders are the consequence of shifts in dietary patterns with high caloric-content food intake. We previously reported that megalin regulates energy homeostasis using blood-brain barrier (BBB) endothelial megalin-deficient (EMD) mice, since these animals developed obesity and metabolic syndrome upon normal chow diet administration. Obesity in mid-life appears to be related to greater dementia risk and represents an increasing global health issue. We demonstrated that EMD phenotype induced impaired learning ability and recognition memory, neurodegeneration, neuroinflammation, reduced neurogenesis, and mitochondrial deregulation associated with higher mitochondrial mass in cortical tissues. METHODS EMD mice were subjected to normal chow and high-fat diet (HFD) for 14 weeks and metabolic changes were evaluated. RESULTS Surprisingly, BBB megalin deficiency protected against HFD-induced obesity improving glucose tolerance and preventing hepatic steatosis. Compared to wild type (wt), the brain cortex in EMD mice showed increased levels of the mitochondrial biogenesis regulator, peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), and uncoupling protein 2 (UCP2), a thermogenic protein involved in the regulation of energy metabolism. This agreed with the previously found increased mitochondrial mass in the transgenic mice. Upon HFD challenge, we demonstrated these two proteins were found elevated in wt mice but reported no changes over the already increased levels in EMD animals. CONCLUSION We propose a protective role for megalin on diet-induce obesity, suggesting this could be related to metabolic disturbances found in dementia through brain endocrine system communications.
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Affiliation(s)
- Fernando Bartolome
- Neurodegenerative Disorders Group, Instituto de Investigacion Hospital 12 de Octubre (i+12), Avda de Cordoba s/n, 28041, Madrid, Spain. .,Network Center for Biomedical Research in Neurodegenerative Diseases, CIBERNED, Madrid, Spain.
| | - Desiree Antequera
- Neurodegenerative Disorders Group, Instituto de Investigacion Hospital 12 de Octubre (i+12), Avda de Cordoba s/n, 28041, Madrid, Spain.,Network Center for Biomedical Research in Neurodegenerative Diseases, CIBERNED, Madrid, Spain
| | - Macarena de la Cueva
- Neurodegenerative Disorders Group, Instituto de Investigacion Hospital 12 de Octubre (i+12), Avda de Cordoba s/n, 28041, Madrid, Spain.,Network Center for Biomedical Research in Neurodegenerative Diseases, CIBERNED, Madrid, Spain
| | - Marcos Rubio-Fernandez
- Neurodegenerative Disorders Group, Instituto de Investigacion Hospital 12 de Octubre (i+12), Avda de Cordoba s/n, 28041, Madrid, Spain.,Network Center for Biomedical Research in Neurodegenerative Diseases, CIBERNED, Madrid, Spain
| | - Nerea Castro
- Neurodegenerative Disorders Group, Instituto de Investigacion Hospital 12 de Octubre (i+12), Avda de Cordoba s/n, 28041, Madrid, Spain.,Network Center for Biomedical Research in Neurodegenerative Diseases, CIBERNED, Madrid, Spain
| | - Consuelo Pascual
- Neurodegenerative Disorders Group, Instituto de Investigacion Hospital 12 de Octubre (i+12), Avda de Cordoba s/n, 28041, Madrid, Spain.,Network Center for Biomedical Research in Neurodegenerative Diseases, CIBERNED, Madrid, Spain
| | - Antoni Camins
- Network Center for Biomedical Research in Neurodegenerative Diseases, CIBERNED, Madrid, Spain.,Unitat de Farmacologia i Farmacognosia, Facultat de Farmacia, Institut de Biomedicina de la UB (IBUB), Universitat de Barcelona, Barcelona, Spain
| | - Eva Carro
- Neurodegenerative Disorders Group, Instituto de Investigacion Hospital 12 de Octubre (i+12), Avda de Cordoba s/n, 28041, Madrid, Spain. .,Network Center for Biomedical Research in Neurodegenerative Diseases, CIBERNED, Madrid, Spain.
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Kukida M, Sawada H, Daugherty A, Lu HS. Megalin: A bridge connecting kidney, the renin-angiotensin system, and atherosclerosis. Pharmacol Res 2020; 151:104537. [PMID: 31707037 PMCID: PMC6980733 DOI: 10.1016/j.phrs.2019.104537] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Accepted: 11/05/2019] [Indexed: 01/21/2023]
Abstract
Megalin is a member of the low-density lipoprotein receptor superfamily. It has been recognized as an endocytic receptor for a large spectrum of ligands. As a consequence, megalin regulates homeostasis of many molecules and affects multiple physiological and pathophysiological functions. The renin-angiotensin system is a hormonal system. A number of studies have reported contributions of the renin-angiotensin system to atherosclerosis. There is evolving evidence that megalin is a regulator of the renin-angiotensin system, and contributes to atherosclerosis. This brief review provides contemporary insights into effects of megalin on renal functions, the renin-angiotensin system, and atherosclerosis.
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Affiliation(s)
- Masayoshi Kukida
- Saha Cardiovascular Research Center and Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Hisashi Sawada
- Saha Cardiovascular Research Center and Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Alan Daugherty
- Saha Cardiovascular Research Center and Department of Physiology, University of Kentucky, Lexington, KY, USA
| | - Hong S Lu
- Saha Cardiovascular Research Center and Department of Physiology, University of Kentucky, Lexington, KY, USA.
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40
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Chen Z, Luciani A, Mateos JM, Barmettler G, Giles RH, Neuhauss SCF, Devuyst O. Transgenic zebrafish modeling low-molecular-weight proteinuria and lysosomal storage diseases. Kidney Int 2019; 97:1150-1163. [PMID: 32061435 DOI: 10.1016/j.kint.2019.11.016] [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: 02/09/2019] [Revised: 10/16/2019] [Accepted: 11/01/2019] [Indexed: 12/12/2022]
Abstract
Epithelial cells lining the proximal tubule of the kidney reabsorb and metabolize most of the filtered low-molecular-weight proteins through receptor-mediated endocytosis and lysosomal processing. Congenital and acquired dysfunctions of the proximal tubule are consistently reflected by the inappropriate loss of solutes including low-molecular-weight proteins in the urine. The zebrafish pronephros shares individual functional segments with the human nephron, including lrp2a/megalin-dependent endocytic transport processes of the proximal tubule. Although the zebrafish has been used as a model organism for toxicological studies and drug discovery, there is no available assay that allows large-scale assessment of proximal tubule function in larval or adult stages. Here we establish a transgenic Tg(lfabp::½vdbp-mCherry) zebrafish line expressing in the liver the N-terminal region of vitamin D-binding protein coupled to the acid-insensitive, red monomeric fluorescent protein mCherry (½vdbp-mCherry). This low-molecular-weight protein construct is secreted into the bloodstream, filtered through the glomerulus, reabsorbed by receptor-mediated endocytosis and processed in the lysosomes of proximal tubule cells of the fish. Thus, our proof-of-concept studies using zebrafish larvae knockout for lrp2a and clcn7 or exposed to known nephrotoxins (gentamicin and cisplatin) demonstrate that this transgenic line is useful to monitor low-molecular-weight proteinuria and lysosomal processing. This represents a powerful new model organism for drug screening and studies of nephrotoxicity.
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Affiliation(s)
- Zhiyong Chen
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | | | - José María Mateos
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Gery Barmettler
- Center for Microscopy and Image Analysis, University of Zurich, Zurich, Switzerland
| | - Rachel H Giles
- Department of Nephrology and Hypertension, Hubrecht Institute, Utrecht, The Netherlands; University Medical Center Utrecht, Utrecht, The Netherlands
| | | | - Olivier Devuyst
- Institute of Physiology, University of Zurich, Zurich, Switzerland.
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Single-Cell Transcriptomics Characterizes Cell Types in the Subventricular Zone and Uncovers Molecular Defects Impairing Adult Neurogenesis. Cell Rep 2019; 25:2457-2469.e8. [PMID: 30485812 DOI: 10.1016/j.celrep.2018.11.003] [Citation(s) in RCA: 110] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2018] [Revised: 09/13/2018] [Accepted: 10/31/2018] [Indexed: 12/26/2022] Open
Abstract
Neural stem cells (NSCs) contribute to plasticity and repair of the adult brain. Niches harboring NSCs regulate stem cell self-renewal and differentiation. We used comprehensive and untargeted single-cell RNA profiling to generate a molecular cell atlas of the largest germinal region of the adult mouse brain, the subventricular zone (SVZ). We characterized >20 neural and non-neural cell types and gained insights into the dynamics of neurogenesis by predicting future cell states based on computational analysis of RNA kinetics. Furthermore, we applied our single-cell approach to document decreased numbers of NSCs, reduced proliferation activity of progenitors, and perturbations in Wnt and BMP signaling pathways in mice lacking LRP2, an endocytic receptor required for SVZ maintenance. Our data provide a valuable resource to study adult neurogenesis and a proof of principle for the power of single-cell RNA sequencing to elucidate neural cell-type-specific alterations in loss-of-function models.
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Bauer R, Tondl P, Schneider WJ. A differentiation program induced by bone morphogenetic proteins 4 and 7 in endodermal epithelial cells provides the molecular basis for efficient nutrient transport by the chicken yolk sac. Dev Dyn 2019; 249:222-236. [PMID: 31691430 PMCID: PMC7028021 DOI: 10.1002/dvdy.129] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 10/17/2019] [Accepted: 10/29/2019] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND The mammalian yolk sac provides nutrients for the growing fetus during critical early developmental processes such as neural tube closure, which precedes the functional maturation of the placenta. In contrast, oviparous species such as the chicken rely solely on the yolk sac for transfer of nutrients from the yolk to the developing embryo. However, the molecular mechanisms that provide the yolk sac with nutrient transfer competence remain poorly understood. RESULTS We demonstrate that the chicken endodermal epithelial cells (EEC), which are in close contact with the yolk, gain their nutrient-transport competence by a paracrine crosstalk with the blood-vessel forming mesodermal cell layer. Bone morphogenetic proteins (BMP) 4 and 7 produced by ectodermal and mesodermal cell layers likely initiate a differentiation program of EECs during the transition from the area vitellina to the area vasculosa. BMPs, by inducing SMAD signaling, promote the up-regulation of endocytic receptor expression and thereby provide the EECs with the molecular machinery to produce triglyceride-rich lipoprotein particles. CONCLUSION This paracrine signaling cascade may constitute the basis for the EEC-mediated mechanism underlying the efficient uptake, degradation, resynthesis, and transfer of yolk-derived nutrients into the embryonic circulation, which assures proper energy supply and development of the growing fetus.
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Affiliation(s)
- Raimund Bauer
- Center for Pathobiochemistry and Genetics, Institute of Medical Chemistry, Medical University of Vienna, Vienna, Austria
| | - Philipp Tondl
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Wolfgang J Schneider
- Department of Medical Biochemistry, Max Perutz Labs, Medical University of Vienna, Vienna, Austria
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43
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Sasai N, Toriyama M, Kondo T. Hedgehog Signal and Genetic Disorders. Front Genet 2019; 10:1103. [PMID: 31781166 PMCID: PMC6856222 DOI: 10.3389/fgene.2019.01103] [Citation(s) in RCA: 81] [Impact Index Per Article: 16.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 10/11/2019] [Indexed: 12/12/2022] Open
Abstract
The hedgehog (Hh) family comprises sonic hedgehog (Shh), Indian hedgehog (Ihh), and desert hedgehog (Dhh), which are versatile signaling molecules involved in a wide spectrum of biological events including cell differentiation, proliferation, and survival; establishment of the vertebrate body plan; and aging. These molecules play critical roles from embryogenesis to adult stages; therefore, alterations such as abnormal expression or mutations of the genes involved and their downstream factors cause a variety of genetic disorders at different stages. The Hh family involves many signaling mediators and functions through complex mechanisms, and achieving a comprehensive understanding of the entire signaling system is challenging. This review discusses the signaling mediators of the Hh pathway and their functions at the cellular and organismal levels. We first focus on the roles of Hh signaling mediators in signal transduction at the cellular level and the networks formed by these factors. Then, we analyze the spatiotemporal pattern of expression of Hh pathway molecules in tissues and organs, and describe the phenotypes of mutant mice. Finally, we discuss the genetic disorders caused by malfunction of Hh signaling-related molecules in humans.
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Affiliation(s)
- Noriaki Sasai
- Developmental Biomedical Science, Division of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan
| | - Michinori Toriyama
- Systems Neurobiology and Medicine, Division of Biological Sciences, Nara Institute of Science and Technology, Ikoma, Japan.,Department of Biomedical Chemistry, School of Science and Technology, Kwansei Gakuin University, Sanda, Japan
| | - Toru Kondo
- Division of Stem Cell Biology, Institute for Genetic Medicine, Hokkaido University, Sapporo, Japan
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Janssens V, Gaide Chevronnay HP, Marie S, Vincent MF, Van Der Smissen P, Nevo N, Vainio S, Nielsen R, Christensen EI, Jouret F, Antignac C, Pierreux CE, Courtoy PJ. Protection of Cystinotic Mice by Kidney-Specific Megalin Ablation Supports an Endocytosis-Based Mechanism for Nephropathic Cystinosis Progression. J Am Soc Nephrol 2019; 30:2177-2190. [PMID: 31548351 DOI: 10.1681/asn.2019040371] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 07/31/2019] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND Deletions or inactivating mutations of the cystinosin gene CTNS lead to cystine accumulation and crystals at acidic pH in patients with nephropathic cystinosis, a rare lysosomal storage disease and the main cause of hereditary renal Fanconi syndrome. Early use of oral cysteamine to prevent cystine accumulation slows progression of nephropathic cystinosis but it is a demanding treatment and not a cure. The source of cystine accumulating in kidney proximal tubular cells and cystine's role in disease progression are unknown. METHODS To investigate whether receptor-mediated endocytosis by the megalin/LRP2 pathway of ultrafiltrated, disulfide-rich plasma proteins could be a source of cystine in proximal tubular cells, we used a mouse model of cystinosis in which conditional excision of floxed megalin/LRP2 alleles in proximal tubular cells of cystinotic mice was achieved by a Cre-LoxP strategy using Wnt4-CRE. We evaluated mice aged 6-9 months for kidney cystine levels and crystals; histopathology, with emphasis on swan-neck lesions and proximal-tubular-cell apoptosis and proliferation (turnover); and proximal-tubular-cell expression of the major apical transporters sodium-phosphate cotransporter 2A (NaPi-IIa) and sodium-glucose cotransporter-2 (SGLT-2). RESULTS Wnt4-CRE-driven megalin/LRP2 ablation in cystinotic mice efficiently blocked kidney cystine accumulation, thereby preventing lysosomal deformations and crystal deposition in proximal tubular cells. Swan-neck lesions were largely prevented and proximal-tubular-cell turnover was normalized. Apical expression of the two cotransporters was also preserved. CONCLUSIONS These observations support a key role of the megalin/LRP2 pathway in the progression of nephropathic cystinosis and provide a proof of concept for the pathway as a therapeutic target.
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Affiliation(s)
- Virginie Janssens
- Cell Biology Unit, de Duve Institute and Université Catholique de Louvain, Brussels, Belgium
| | | | - Sandrine Marie
- Biochemical Genetics, Academic Hospital Saint-Luc, Brussels, Belgium
| | | | - Patrick Van Der Smissen
- Cell Biology Unit, de Duve Institute and Université Catholique de Louvain, Brussels, Belgium
| | - Nathalie Nevo
- Laboratory of Hereditary Kidney Diseases, Institut National de la Santé et de la Recherche Médicale (INSERM) U1163, Imagine Institute, Paris Descartes University, Paris, France
| | - Seppo Vainio
- Faculty of Biochemistry and Molecular Medicine, Laboratory of Developmental Biology, Oulu Center for Cell-Matrix Research, Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Rikke Nielsen
- Department of Biomedicine, Aarhus University, Aarhus, Denmark; and
| | | | - François Jouret
- Groupe Interdisciplinaire de Génoprotéomique Appliquée (GIGA), Cardiovascular Sciences, University of Liège, Liège, Belgium
| | - Corinne Antignac
- Laboratory of Hereditary Kidney Diseases, Institut National de la Santé et de la Recherche Médicale (INSERM) U1163, Imagine Institute, Paris Descartes University, Paris, France
| | - Christophe E Pierreux
- Cell Biology Unit, de Duve Institute and Université Catholique de Louvain, Brussels, Belgium;
| | - Pierre J Courtoy
- Cell Biology Unit, de Duve Institute and Université Catholique de Louvain, Brussels, Belgium
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Storm T, Burgoyne T, Dunaief JL, Christensen EI, Futter C, Nielsen R. Selective Ablation of Megalin in the Retinal Pigment Epithelium Results in Megaophthalmos, Macromelanosome Formation and Severe Retina Degeneration. Invest Ophthalmol Vis Sci 2019; 60:322-330. [PMID: 30665232 PMCID: PMC6343679 DOI: 10.1167/iovs.18-25667] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose Mutations in the megalin-encoding gene, LRP2, cause high myopia as seen in patients suffering from Donnai-Barrow/facio-oculo-acoustico-renal syndrome. Megalin is present in both the nonpigmented epithelium of the ciliary body and in the RPE. In this study, we set out to establish an animal model to study the mechanisms underlying the ocular phenotype and to establish if high myopia/megaophthalmos is induced by postnatal megalin-deficiency in the RPE. Methods Postnatal RPE-specific deletion of megalin was generated by crossing mice bearing a homozygous loxP-flanked Lrp2 allele with transgenic mice expressing the Cre recombinase driven by the BEST1 promotor. The model was investigated by immunohistologic techniques, and transmission electron microscopy. Results Mice with postnatal RPE-specific loss of megalin developed a megaophthalmos phenotype with dramatic increase in ocular size and severe retinal thinning associated with compromised vision. This phenotype was present at postnatal day 14, indicating rapid development in the period from onset of BEST1 promotor activity at postnatal day 10. Additionally, RPE melanosomes exhibited abnormal size and morphology, suggested by electron tomography to be caused by fusion events between multiple melanosomes. Conclusions Postnatal loss of megalin in the RPE induces dramatic and rapid ocular growth and retinal degeneration compatible with the high myopia observed in Donnai-Barrow patients. The morphologic changes of RPE melanosomes, believed to be largely inert and fully differentiated at birth, suggested a continued plasticity of mature melanosomes and a requirement for megalin to maintain their number and morphology.
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Affiliation(s)
- Tina Storm
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | | | - Joshua L Dunaief
- F.M. Kirby Center for Molecular Ophthalmology, Scheie Eye Institute, University of Pennsylvania, Philadelphia, Pennsylvania, United States
| | - Erik I Christensen
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
| | - Clare Futter
- UCL Institute of Ophthalmology, London, United Kingdom
| | - Rikke Nielsen
- Department of Biomedicine, Faculty of Health Sciences, Aarhus University, Aarhus, Denmark
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Cabezas F, Farfán P, Marzolo MP. Participation of the SMAD2/3 signalling pathway in the down regulation of megalin/LRP2 by transforming growth factor beta (TGF-ß1). PLoS One 2019; 14:e0213127. [PMID: 31120873 PMCID: PMC6532859 DOI: 10.1371/journal.pone.0213127] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 05/08/2019] [Indexed: 12/19/2022] Open
Abstract
Megalin/LRP2 is a receptor that plays important roles in the physiology of several organs, such as kidney, lung, intestine, and gallbladder and also in the physiology of the nervous system. Megalin expression is reduced in diseases associated with fibrosis, including diabetic nephropathy, hepatic fibrosis and cholelithiasis, as well as in some breast and prostate cancers. One of the hallmarks of these conditions is the presence of the cytokine transforming growth factor beta (TGF-ß). Although TGF-ß has been implicated in the reduction of megalin levels, the molecular mechanism underlying this regulation is not well understood. Here, we show that treatment of two epithelial cell lines (from kidney and gallbladder) with TGF-ß1 is associated with decreased megalin mRNA and protein levels, and that these effects are reversed by inhibiting the TGF-ß1 type I receptor (TGF-ßRI). Based on in silico analyses, the two SMAD-binding elements (SBEs) in the megalin promoter are located at positions -57 and -605. Site-directed mutagenesis of the SBEs and chromatin immunoprecipitation (ChIP) experiments revealed that SMAD2/3 transcription factors interact with SBEs. Both the presence of SMAD2/3 and intact SBEs were associated with repression of the megalin promoter, in the absence as well in the presence of TGF-ß1. Also, reduced megalin expression and promoter activation triggered by high concentration of albumin are dependent on the expression of SMAD2/3. Interestingly, the histone deacetylase inhibitor Trichostatin A (TSA), which induces megalin expression, reduced the effects of TGF-ß1 on megalin mRNA levels. These data show the significance of TGF-ß and the SMAD2/3 signalling pathway in the regulation of megalin and explain the decreased megalin levels observed under conditions in which TGF-ß is upregulated, including fibrosis-associated diseases and cancer.
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Affiliation(s)
- Felipe Cabezas
- Laboratorio de Tráfico Intracelular y Señalización, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Pamela Farfán
- Laboratorio de Tráfico Intracelular y Señalización, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - María-Paz Marzolo
- Laboratorio de Tráfico Intracelular y Señalización, Departamento de Biología Celular y Molecular, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
- * E-mail:
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Gravotta D, Perez Bay A, Jonker CTH, Zager PJ, Benedicto I, Schreiner R, Caceres PS, Rodriguez-Boulan E. Clathrin and clathrin adaptor AP-1 control apical trafficking of megalin in the biosynthetic and recycling routes. Mol Biol Cell 2019; 30:1716-1728. [PMID: 31091172 PMCID: PMC6727755 DOI: 10.1091/mbc.e18-12-0811] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
Abstract
Megalin (gp330, LRP-2) is a protein structurally related to the low-density lipoprotein receptor family that displays a large luminal domain with multiligand binding properties. Megalin localizes to the apical surface of multiple epithelia, where it participates in endocytosis of a variety of ligands performing roles important for development or homeostasis. We recently described the apical recycling pathway of megalin in Madin–Darby canine kidney (MDCK) cells and found that it is a long-lived, fast recycling receptor with a recycling turnover of 15 min and a half-life of 4.8 h. Previous work implicated clathrin and clathrin adaptors in the polarized trafficking of fast recycling basolateral receptors. Hence, here we study the role of clathrin and clathrin adaptors in megalin’s apical localization and trafficking. Targeted silencing of clathrin or the γ1 subunit of clathrin adaptor AP-1 by RNA interference in MDCK cells disrupted apical localization of megalin, causing its redistribution to the basolateral membrane. In contrast, silencing of the γ2 subunit of AP-1 had no effect on megalin polarity. Trafficking assays we developed using FM4-HA-miniMegalin-GFP, a reversible conditional endoplasmic reticulum–retained chimera, revealed that clathrin and AP-1 silencing disrupted apical sorting of megalin in both biosynthetic and recycling routes. Our experiments demonstrate that clathrin and AP-1 control the sorting of an apical transmembrane protein.
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Affiliation(s)
- Diego Gravotta
- Margaret Dyson Vision Research Institute, Weill Cornell Medicine, New York, NY 10065
| | - Andres Perez Bay
- Margaret Dyson Vision Research Institute, Weill Cornell Medicine, New York, NY 10065
| | - Caspar T H Jonker
- Margaret Dyson Vision Research Institute, Weill Cornell Medicine, New York, NY 10065
| | - Patrick J Zager
- Margaret Dyson Vision Research Institute, Weill Cornell Medicine, New York, NY 10065
| | - Ignacio Benedicto
- Margaret Dyson Vision Research Institute, Weill Cornell Medicine, New York, NY 10065
| | - Ryan Schreiner
- Margaret Dyson Vision Research Institute, Weill Cornell Medicine, New York, NY 10065
| | - Paulo S Caceres
- Margaret Dyson Vision Research Institute, Weill Cornell Medicine, New York, NY 10065
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Ohuchi H, Sato K, Habuta M, Fujita H, Bando T. Congenital eye anomalies: More mosaic than thought? Congenit Anom (Kyoto) 2019; 59:56-73. [PMID: 30039880 DOI: 10.1111/cga.12304] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Revised: 07/16/2018] [Accepted: 07/17/2018] [Indexed: 12/13/2022]
Abstract
The eye is a sensory organ that primarily captures light and provides the sense of sight, as well as delivering non-visual light information involving biological rhythms and neurophysiological activities to the brain. Since the early 1990s, rapid advances in molecular biology have enabled the identification of developmental genes, genes responsible for human congenital diseases, and relevant genes of mutant animals with various anomalies. In this review, we first look at the development of the eye, and we highlight seminal reports regarding archetypal gene defects underlying three developmental ocular disorders in humans: (1) holoprosencephaly (HPE), with cyclopia being exhibited in the most severe cases; (2) microphthalmia, anophthalmia, and coloboma (MAC) phenotypes; and (3) anterior segment dysgenesis (ASDG), known as Peters anomaly and its related disorders. The recently developed methods, such as next-generation sequencing and genome editing techniques, have aided the discovery of gene mutations in congenital eye diseases and gene functions in normal eye development. Finally, we discuss Pax6-genome edited mosaic eyes and propose that somatic mosaicism in developmental gene mutations should be considered a causal factor for variable phenotypes, sporadic cases, and de novo mutations in human developmental disorders.
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Affiliation(s)
- Hideyo Ohuchi
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Keita Sato
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Munenori Habuta
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Hirofumi Fujita
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
| | - Tetsuya Bando
- Department of Cytology and Histology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan
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Grinblat Y, Lipinski RJ. A forebrain undivided: Unleashing model organisms to solve the mysteries of holoprosencephaly. Dev Dyn 2019; 248:626-633. [PMID: 30993762 DOI: 10.1002/dvdy.41] [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: 03/15/2019] [Revised: 04/10/2019] [Accepted: 04/10/2019] [Indexed: 12/13/2022] Open
Abstract
Evolutionary conservation and experimental tractability have made animal model systems invaluable tools in our quest to understand human embryogenesis, both normal and abnormal. Standard genetic approaches, particularly useful in understanding monogenic diseases, are no longer sufficient as research attention shifts toward multifactorial outcomes. Here, we examine this progression through the lens of holoprosencephaly (HPE), a common human malformation involving incomplete forebrain division, and a classic example of an etiologically complex outcome. We relate the basic underpinning of HPE pathogenesis to critical cell-cell interactions and signaling molecules discovered through embryological and genetic approaches in multiple model organisms, and discuss the role of the mouse model in functional examination of HPE-linked genes. We then outline the most critical remaining gaps to understanding human HPE, including the conundrum of incomplete penetrance/expressivity and the role of gene-environment interactions. To tackle these challenges, we outline a strategy that leverages new and emerging technologies in multiple model systems to solve the puzzle of HPE.
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Affiliation(s)
- Yevgenya Grinblat
- Department of Integrative Biology, University of Wisconsin, Madison, Wisconsin.,Department of Neuroscience, University of Wisconsin, Madison, Wisconsin.,McPherson Eye Research Institute, University of Wisconsin, Madison, Wisconsin
| | - Robert J Lipinski
- Department of Comparative Biosciences, School of Veterinary Medicine, University of Wisconsin, Madison, Wisconsin.,Molecular and Environmental Toxicology Center, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin
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50
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Abramyan J. Hedgehog Signaling and Embryonic Craniofacial Disorders. J Dev Biol 2019; 7:E9. [PMID: 31022843 PMCID: PMC6631594 DOI: 10.3390/jdb7020009] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/18/2019] [Accepted: 04/23/2019] [Indexed: 02/06/2023] Open
Abstract
Since its initial discovery in a Drosophila mutagenesis screen, the Hedgehog pathway has been revealed to be instrumental in the proper development of the vertebrate face. Vertebrates possess three hedgehog paralogs: Sonic hedgehog (Shh), Indian hedgehog (Ihh), and Desert hedgehog (Dhh). Of the three, Shh has the broadest range of functions both in the face and elsewhere in the embryo, while Ihh and Dhh play more limited roles. The Hedgehog pathway is instrumental from the period of prechordal plate formation early in the embryo, until the fusion of the lip and secondary palate, which complete the major patterning events of the face. Disruption of Hedgehog signaling results in an array of developmental disorders in the face, ranging from minor alterations in the distance between the eyes to more serious conditions such as severe clefting of the lip and palate. Despite its critical role, Hedgehog signaling seems to be disrupted through a number of mechanisms that may either be direct, as in mutation of a downstream target of the Hedgehog ligand, or indirect, such as mutation in a ciliary protein that is otherwise seemingly unrelated to the Hedgehog pathway. A number of teratogens such as alcohol, statins and steroidal alkaloids also disrupt key aspects of Hedgehog signal transduction, leading to developmental defects that are similar, if not identical, to those of Hedgehog pathway mutations. The aim of this review is to highlight the variety of roles that Hedgehog signaling plays in developmental disorders of the vertebrate face.
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Affiliation(s)
- John Abramyan
- Department of Natural Sciences, University of Michigan-Dearborn, Dearborn, MI 48128, USA.
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