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Ng ESY, Hu J, Jiang Z, Radu RA. Impaired cathepsin D in retinal pigment epithelium cells mediates Stargardt disease pathogenesis. FASEB J 2024; 38:e23720. [PMID: 38837708 DOI: 10.1096/fj.202400210rr] [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: 01/26/2024] [Revised: 05/12/2024] [Accepted: 05/21/2024] [Indexed: 06/07/2024]
Abstract
Recessive Stargardt disease (STGD1) is an inherited juvenile maculopathy caused by mutations in the ABCA4 gene, for which there is no suitable treatment. Loss of functional ABCA4 in the retinal pigment epithelium (RPE) alone, without contribution from photoreceptor cells, was shown to induce STGD1 pathology. Here, we identified cathepsin D (CatD), the primary RPE lysosomal protease, as a key molecular player contributing to endo-lysosomal dysfunction in STGD1 using a newly developed "disease-in-a-dish" RPE model from confirmed STGD1 patients. Induced pluripotent stem cell (iPSC)-derived RPE originating from three STGD1 patients exhibited elevated lysosomal pH, as previously reported in Abca4-/- mice. CatD protein maturation and activity were impaired in RPE from STGD1 patients and Abca4-/- mice. Consequently, STGD1 RPE cells have reduced photoreceptor outer segment degradation and abnormal accumulation of α-synuclein, the natural substrate of CatD. Furthermore, dysfunctional ABCA4 in STGD1 RPE cells results in intracellular accumulation of autofluorescent material and phosphatidylethanolamine (PE). The altered distribution of PE associated with the internal membranes of STGD1 RPE cells presumably compromises LC3-associated phagocytosis, contributing to delayed endo-lysosomal degradation activity. Drug-mediated re-acidification of lysosomes in the RPE of STGD1 restores CatD functional activity and reduces the accumulation of immature CatD protein loads. This preclinical study validates the contribution of CatD deficiencies to STGD1 pathology and provides evidence for an efficacious therapeutic approach targeting RPE cells. Our findings support a cell-autonomous RPE-driven pathology, informing future research aimed at targeting RPE cells to treat ABCA4-mediated retinopathies.
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Affiliation(s)
- Eunice Sze Yin Ng
- UCLA Stein Eye Institute, University of California, Los Angeles, California, USA
- Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
- Molecular, Cellular, and Integrative Physiology Interdepartmental Program, University of California, Los Angeles, California, USA
| | - Jane Hu
- UCLA Stein Eye Institute, University of California, Los Angeles, California, USA
- Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Zhichun Jiang
- UCLA Stein Eye Institute, University of California, Los Angeles, California, USA
- Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
| | - Roxana A Radu
- UCLA Stein Eye Institute, University of California, Los Angeles, California, USA
- Department of Ophthalmology, David Geffen School of Medicine, University of California, Los Angeles, California, USA
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2
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Ng ESY, Kady N, Hu J, Dave A, Jiang Z, Pei J, Gorin MB, Matynia A, Radu RA. Membrane Attack Complex Mediates Retinal Pigment Epithelium Cell Death in Stargardt Macular Degeneration. Cells 2022; 11:3462. [PMID: 36359858 PMCID: PMC9655712 DOI: 10.3390/cells11213462] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2022] [Revised: 10/28/2022] [Accepted: 10/30/2022] [Indexed: 08/22/2023] Open
Abstract
Recessive Stargardt disease (STGD1) is an inherited retinopathy caused by mutations in the ABCA4 gene. The ABCA4 protein is a phospholipid-retinoid flippase in the outer segments of photoreceptors and the internal membranes of retinal pigment epithelial (RPE) cells. Here, we show that RPE cells derived via induced pluripotent stem-cell from a molecularly and clinically diagnosed STGD1 patient exhibited reduced ABCA4 protein and diminished activity compared to a normal subject. Consequently, STGD1 RPE cells accumulated intracellular autofluorescence-lipofuscin and displayed increased complement C3 activity. The level of C3 inversely correlated with the level of CD46, an early negative regulator of the complement cascade. Persistent complement dysregulation led to deposition of the membrane attack complex on the surface of RPE cells, decrease in transepithelial resistance, and subsequent cell death. These findings are strong evidence of complement-mediated RPE cell damage in STGD1, in the absence of photoreceptors, caused by reduced CD46 regulatory protein.
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Affiliation(s)
- Eunice Sze Yin Ng
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
- Molecular Cellular and Integrative Physiology Interdepartmental Program, University of California, Los Angeles, CA 90095, USA
| | - Nermin Kady
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
- Department of Internal Medicine, Division of Hematology and Oncology, University of Michigan, Ann Arbor, MI 48109, USA
- Clinical Pathology Department, Faculty of Medicine, Mansoura University, Mansoura 35516, Egypt
| | - Jane Hu
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Arpita Dave
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Zhichun Jiang
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Jacqueline Pei
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Michael B. Gorin
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Anna Matynia
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
| | - Roxana A. Radu
- UCLA Stein Eye Institute and Department of Ophthalmology, David Geffen School of Medicine at UCLA, University of California at Los Angeles, CA 90095, USA
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3
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Zhang D, Gao M, Jin Q, Ni Y, Li H, Jiang C, Zhang J. Development of Duramycin-Based Molecular Probes for Cell Death Imaging. Mol Imaging Biol 2022; 24:612-629. [PMID: 35142992 DOI: 10.1007/s11307-022-01707-3] [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: 10/09/2021] [Revised: 01/10/2022] [Accepted: 01/27/2022] [Indexed: 10/19/2022]
Abstract
Cell death is involved in numerous pathological conditions such as cardiovascular disorders, ischemic stroke and organ transplant rejection, and plays a critical role in the treatment of cancer. Cell death imaging can serve as a noninvasive means to detect the severity of tissue damage, monitor the progression of diseases, and evaluate the effectiveness of treatments, which help to provide prognostic information and guide the formulation of individualized treatment plans. The high abundance of phosphatidylethanolamine (PE), which is predominantly confined to the inner leaflet of the lipid bilayer membrane in healthy mammalian cells, becomes exposed on the cell surface in the early stages of apoptosis or accessible to the extracellular milieu when the cell suffers from necrosis, thus representing an attractive target for cell death imaging. Duramycin is a tetracyclic polypeptide that contains 19 amino acids and can bind to PE with excellent affinity and specificity. Additionally, this peptide has several favorable structural traits including relatively low molecular weight, stability to enzymatic hydrolysis, and ease of conjugation and labeling. All these highlight the potential of duramycin as a candidate ligand for developing PE-specific molecular probes. By far, a couple of duramycin-based molecular probes such as Tc-99 m-, F-18-, or Ga-68-labeled duramycin have been developed to target exposed PE for in vivo noninvasive imaging of cell death in different animal models. In this review article, we describe the state of the art with respect to in vivo imaging of cell death using duramycin-based molecular probes, as validated by immunohistopathology.
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Affiliation(s)
- Dongjian Zhang
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, People's Republic of China.,Laboratories of Translational Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing, 210028, Jiangsu Province, People's Republic of China
| | - Meng Gao
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, People's Republic of China.,Laboratories of Translational Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing, 210028, Jiangsu Province, People's Republic of China
| | - Qiaomei Jin
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, People's Republic of China.,Laboratories of Translational Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing, 210028, Jiangsu Province, People's Republic of China
| | - Yicheng Ni
- Theragnostic Laboratory, Campus Gasthuisberg, 3000, Leuven, Leuven, KU, Belgium
| | - Huailiang Li
- Department of General Surgery, Nanjing Lishui District Hospital of Traditional Chinese Medicine, Nanjing, 211200, Jiangsu Province, People's Republic of China
| | - Cuihua Jiang
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, People's Republic of China. .,Laboratories of Translational Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing, 210028, Jiangsu Province, People's Republic of China.
| | - Jian Zhang
- Affiliated Hospital of Integrated Traditional Chinese and Western Medicine, Nanjing University of Chinese Medicine, Nanjing, 210028, Jiangsu Province, People's Republic of China. .,Laboratories of Translational Medicine, Jiangsu Province Academy of Traditional Chinese Medicine, Nanjing, 210028, Jiangsu Province, People's Republic of China.
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4
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Kundu R, Chandra A, Datta A. Fluorescent Chemical Tools for Tracking Anionic Phospholipids. Isr J Chem 2021. [DOI: 10.1002/ijch.202100003] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Rajasree Kundu
- Department of Chemical Sciences Tata Institute of Fundamental Research 1 Homi Bhabha Road, Colaba Mumbai 400005 India
| | - Amitava Chandra
- Department of Chemical Sciences Tata Institute of Fundamental Research 1 Homi Bhabha Road, Colaba Mumbai 400005 India
| | - Ankona Datta
- Department of Chemical Sciences Tata Institute of Fundamental Research 1 Homi Bhabha Road, Colaba Mumbai 400005 India
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5
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Vestergaard M, Berglund NA, Hsu PC, Song C, Koldsø H, Schiøtt B, Sansom MSP. Structure and Dynamics of Cinnamycin-Lipid Complexes: Mechanisms of Selectivity for Phosphatidylethanolamine Lipids. ACS OMEGA 2019; 4:18889-18899. [PMID: 31737850 PMCID: PMC6854821 DOI: 10.1021/acsomega.9b02949] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2019] [Accepted: 10/11/2019] [Indexed: 05/31/2023]
Abstract
Cinnamycin is a lantibiotic peptide, which selectively binds to and permeabilizes membranes containing phosphatidylethanolamine (PE) lipids. As PE is a major component of many bacterial cell membranes, cinnamycin has considerable potential for destroying these. In this study, molecular dynamics simulations are used to elucidate the structure of a lipid-cinnamycin complex and the origin of selective lipid binding. The simulations reveal that cinnamycin selectively binds to PE by forming an extensive hydrogen-bonding network involving all three hydrogen atoms of the primary ammonium group of the PE head group. The substitution of a single hydrogen atom with a methyl group on the ammonium nitrogen destabilizes this hydrogen-bonding network. In addition to binding the primary ammonium group, cinnamycin also interacts with the phosphate group of the lipid through a previously uncharacterized phosphate-binding site formed by the backbone Phe10-Abu11-Phe12-Val13 moieties (Abu = 1-α-aminobutyric acid). In addition, hydroxylation of Asp15 at Cβ plays a role in selective binding of PE due to its tight interaction with the charged amine of the lipid head group. The simulations reveal that the position and orientation of the peptide in the membrane depend on the type of lipid to which it binds, suggesting a reason for why cinnamycin selectively permeabilizes PE-containing membranes.
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Affiliation(s)
- Mikkel Vestergaard
- Center
for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience
Center (iNANO), Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Nils Anton Berglund
- Center
for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience
Center (iNANO), Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Pin-Chia Hsu
- Center
for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience
Center (iNANO), Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Chen Song
- Department
of Biochemistry, University of Oxford, South Parks Road, OX1 3QU Oxford, United Kingdom
| | - Heidi Koldsø
- Department
of Biochemistry, University of Oxford, South Parks Road, OX1 3QU Oxford, United Kingdom
| | - Birgit Schiøtt
- Center
for Insoluble Protein Structures (inSPIN), Interdisciplinary Nanoscience
Center (iNANO), Department of Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Aarhus C, Denmark
| | - Mark S. P. Sansom
- Department
of Biochemistry, University of Oxford, South Parks Road, OX1 3QU Oxford, United Kingdom
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6
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Smith TE, Pond CD, Pierce E, Harmer ZP, Kwan J, Zachariah MM, Harper MK, Wyche TP, Matainaho TK, Bugni TS, Barrows LR, Ireland CM, Schmidt EW. Accessing chemical diversity from the uncultivated symbionts of small marine animals. Nat Chem Biol 2018; 14:179-185. [PMID: 29291350 PMCID: PMC5771842 DOI: 10.1038/nchembio.2537] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2017] [Accepted: 11/09/2017] [Indexed: 12/15/2022]
Abstract
Chemistry drives many biological interactions between the microbiota and host animals, yet it is often challenging to identify the chemicals involved. This poses a problem, as such small molecules are excellent sources of potential pharmaceuticals, pretested by nature for animal compatibility. We discovered anti-HIV compounds from small, marine tunicates from the Eastern Fields of Papua New Guinea. Tunicates are a reservoir for novel bioactive chemicals, yet their small size often impedes identification or even detection of the chemicals within. We solved this problem by combining chemistry, metagenomics, and synthetic biology to directly identify and synthesize the natural products. We show that these anti-HIV compounds, the divamides, are a novel family of lanthipeptides produced by symbiotic bacteria living in the tunicate. Neighboring animal colonies contain structurally related divamides that differ starkly in their biological properties, suggesting a role for biosynthetic plasticity in a native context where biological interactions take place.
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Affiliation(s)
- Thomas E Smith
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Christopher D Pond
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, USA
| | - Elizabeth Pierce
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Zachary P Harmer
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Jason Kwan
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Malcolm M Zachariah
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Mary Kay Harper
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Thomas P Wyche
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin, Madison, Wisconsin, USA
| | - Teatulohi K Matainaho
- Discipline of Pharmacology, School of Medicine and Health Sciences, University of Papua New Guinea, National Capital District 111, Papua New Guinea
| | - Tim S Bugni
- Pharmaceutical Sciences Division, School of Pharmacy, University of Wisconsin, Madison, Wisconsin, USA
| | - Louis R Barrows
- Department of Pharmacology and Toxicology, University of Utah, Salt Lake City, Utah, USA
| | - Chris M Ireland
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
| | - Eric W Schmidt
- Department of Medicinal Chemistry, University of Utah, Salt Lake City, Utah, USA
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7
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Early endosome as a pathogenic target for antiphosphatidylethanolamine antibodies. Proc Natl Acad Sci U S A 2017; 114:13798-13803. [PMID: 29229837 DOI: 10.1073/pnas.1714027115] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Phosphatidylethanolamine (PE) is a major phospholipid species with important roles in membrane trafficking and reorganization. Accumulating clinical data indicate that the presence of circulating antibodies against PE is positively correlated with the symptoms of antiphospholipid syndromes (APS), including thrombosis and repeated pregnancy loss. However, PE is generally sequestered inside a normal resting cell, and the mechanism by which circulating anti-PE antibodies access cellular PE remains unknown. The studies presented here were conducted with synthetic PE-binding agents, plasma samples from patients with anti-PE autoimmunity, and purified anti-PE antibodies. The results suggest that the cellular vulnerability to anti-PE antibodies may be mediated by the binding of PE molecules in the membrane of the early endosome. Endosomal PE binding led to functional changes in endothelial cells, including declines in proliferation and increases in the production of reactive oxygen species, as well as the expression of inflammatory molecules. Collectively, our findings provide insight into the etiology of anti-PE autoimmunity and, because endosomes are of central importance in almost all types of cells, could have important implications for a wide range of biological processes.
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8
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Phosphatidylethanolamine targeting for cell death imaging in early treatment response evaluation and disease diagnosis. Apoptosis 2017. [DOI: 10.1007/s10495-017-1384-0] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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9
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Isolation and structure determination of a new lantibiotic cinnamycin B from Actinomadura atramentaria based on genome mining. J Ind Microbiol Biotechnol 2016; 43:1159-65. [PMID: 27255974 DOI: 10.1007/s10295-016-1788-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 05/21/2016] [Indexed: 01/26/2023]
Abstract
New lantibiotic cinnamycin B was isolated from the extract of Actinomadura atramentaria NBRC 14695(T), based on genome mining and chemical investigation. The partial structure of cinnamycin B was established by 2D NMR experiments, which indicated that cinnamycin B had same methyl lanthionine bridging pattern with cinnamycin. The reduction with NaBH4-NiCl2 afforded the reduced cinnamycin B, and MS/MS experiment indicated the presence of hydroxy asparatic acid in the molecule. Cinnamycin B showed an antibacterial activity against Streptomyces antibioticus with dosage of 5 μg (0.5μL, 10 mg/mL solution) at spot-on-lawn testing method. The gene cluster of cinnamycin B on the genome of A. atramentaria was identified and discussed in comparison with that of cinnamycin.
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10
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Virion-associated phosphatidylethanolamine promotes TIM1-mediated infection by Ebola, dengue, and West Nile viruses. Proc Natl Acad Sci U S A 2015; 112:14682-7. [PMID: 26575624 DOI: 10.1073/pnas.1508095112] [Citation(s) in RCA: 93] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Phosphatidylserine (PS) receptors contribute to two crucial biological processes: apoptotic clearance and entry of many enveloped viruses. In both cases, they recognize PS exposed on the plasma membrane. Here we demonstrate that phosphatidylethanolamine (PE) is also a ligand for PS receptors and that this phospholipid mediates phagocytosis and viral entry. We show that a subset of PS receptors, including T-cell immunoglobulin (Ig) mucin domain protein 1 (TIM1), efficiently bind PE. We further show that PE is present in the virions of flaviviruses and filoviruses, and that the PE-specific cyclic peptide lantibiotic agent Duramycin efficiently inhibits the entry of West Nile, dengue, and Ebola viruses. The inhibitory effect of Duramycin is specific: it inhibits TIM1-mediated, but not L-SIGN-mediated, virus infection, and it does so by blocking virus attachment to TIM1. We further demonstrate that PE is exposed on the surface of apoptotic cells, and promotes their phagocytic uptake by TIM1-expressing cells. Together, our data show that PE plays a key role in TIM1-mediated virus entry, suggest that disrupting PE association with PS receptors is a promising broad-spectrum antiviral strategy, and deepen our understanding of the process by which apoptotic cells are cleared.
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