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Barabutis N, Akhter MS. Unfolded protein response suppression potentiates LPS-induced barrier dysfunction and inflammation in bovine pulmonary artery endothelial cells. Tissue Barriers 2024; 12:2232245. [PMID: 37436424 DOI: 10.1080/21688370.2023.2232245] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Accepted: 06/27/2023] [Indexed: 07/13/2023] Open
Abstract
The development of novel strategies to counteract diseases related to barrier dysfunction is a priority, since sepsis and acute respiratory distress syndrome are still associated with high mortality rates. In the present study, we focus on the effects of the unfolded protein response suppressor (UPR) 4-Phenylbutyrate (4-PBA) in Lipopolysaccharides (LPS)-induced endothelial injury, to investigate the effects of that compound in the corresponding damage. 4-PBA suppressed binding immunoglobulin protein (BiP) - a UPR activation marker - and potentiated LPS - induced signal transducer and activator of transcription 3 (STAT3) and extracellular signal‑regulated protein kinase (ERK) 1/2 activation. In addition to those effects, 4-PBA enhanced paracellular hyperpermeability in inflamed bovine pulmonary endothelial cells, and did not affect cell viability in moderate concentrations. Our observations suggest that UPR suppression due to 4-PBA augments LPS-induced endothelial injury, as well as the corresponding barrier disruption.
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Affiliation(s)
- Nektarios Barabutis
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana, USA
| | - Mohammad S Akhter
- School of Basic Pharmaceutical and Toxicological Sciences, College of Pharmacy, University of Louisiana Monroe, Monroe, Louisiana, USA
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2
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Kasture AS, Fischer FP, Kunert L, Burger ML, Burgstaller AC, El-Kasaby A, Hummel T, Sucic S. Drosophila melanogaster as a model for unraveling unique molecular features of epilepsy elicited by human GABA transporter 1 variants. Front Neurosci 2023; 16:1074427. [PMID: 36741049 PMCID: PMC9893286 DOI: 10.3389/fnins.2022.1074427] [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: 10/19/2022] [Accepted: 12/21/2022] [Indexed: 01/20/2023] Open
Abstract
Mutations in the human γ-aminobutyric acid (GABA) transporter 1 (hGAT-1) can instigate myoclonic-atonic and other generalized epilepsies in the afflicted individuals. We systematically examined fifteen hGAT-1 disease variants, all of which dramatically reduced or completely abolished GABA uptake activity. Many of these loss-of-function variants were absent from their regular site of action at the cell surface, due to protein misfolding and/or impaired trafficking machinery (as verified by confocal microscopy and de-glycosylation experiments). A modest fraction of the mutants displayed correct targeting to the plasma membrane, but nonetheless rendered the mutated proteins devoid of GABA transport, possibly due to structural alterations in the GABA binding site/translocation pathway. We here focused on a folding-deficient A288V variant. In flies, A288V reiterated its impeded expression pattern, closely mimicking the ER-retention demonstrated in transfected HEK293 cells. Functionally, A288V presented a temperature-sensitive seizure phenotype in fruit flies. We employed diverse small molecules to restore the expression and activity of folding-deficient hGAT-1 epilepsy variants, in vitro (in HEK293 cells) and in vivo (in flies). We identified three compounds (chemical and pharmacological chaperones) conferring moderate rescue capacity for several variants. Our data grant crucial new insights into: (i) the molecular basis of epilepsy in patients harboring hGAT-1 mutations, and (ii) a proof-of-principle that protein folding deficits in disease-associated hGAT-1 variants can be corrected using the pharmacochaperoning approach. Such innovative pharmaco-therapeutic prospects inspire the rational design of novel drugs for alleviating the clinical symptoms triggered by the numerous emerging pathogenic mutations in hGAT-1.
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Affiliation(s)
- Ameya S. Kasture
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria,Department of Neuroscience and Developmental Biology, University of Vienna, Vienna, Austria
| | - Florian P. Fischer
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria,Department of Epileptology and Neurology, University of Aachen, Aachen, Germany
| | - Lisa Kunert
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna, Austria
| | - Melanie L. Burger
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | | | - Ali El-Kasaby
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Thomas Hummel
- Department of Neuroscience and Developmental Biology, University of Vienna, Vienna, Austria
| | - Sonja Sucic
- Institute of Pharmacology, Medical University of Vienna, Vienna, Austria,*Correspondence: Sonja Sucic,
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3
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Angenoorth TJF, Maier J, Stankovic S, Bhat S, Sucic S, Freissmuth M, Sitte HH, Yang JW. Rescue of Misfolded Organic Cation Transporter 3 Variants. Cells 2022; 12:39. [PMID: 36611832 PMCID: PMC9818475 DOI: 10.3390/cells12010039] [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: 11/18/2022] [Revised: 12/13/2022] [Accepted: 12/19/2022] [Indexed: 12/24/2022] Open
Abstract
Organic cation transporters (OCTs) are membrane proteins that take up monoamines, cationic drugs and xenobiotics. We previously reported novel missense mutations of organic cation transporter 3 (OCT3, SLC22A3), some with drastically impacted transport capabilities compared to wildtype. For some variants, this was due to ER retention and subsequent degradation of the misfolded transporter. For other transporter families, it was previously shown that treatment of misfolded variants with pharmacological and chemical chaperones could restore transport function to a certain degree. To investigate two potentially ER-bound, misfolded variants (D340G and R348W), we employed confocal and biochemical analyses. In addition, radiotracer uptake assays were conducted to assess whether pre-treatment with chaperones could restore transporter function. We show that pre-treatment of cells with the chemical chaperone 4-PBA (4-phenyl butyric acid) leads to increased membrane expression of misfolded variants and is associated with increased transport capacity of D340G (8-fold) and R348W (1.5 times) compared to untreated variants. We herein present proof of principle that folding-deficient SLC22 transporter variants, in particular those of OCT3, are amenable to rescue by chaperones. These findings need to be extended to other SLC22 members with corroborated disease associations.
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Affiliation(s)
- Thomas J. F. Angenoorth
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
| | - Julian Maier
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
| | - Stevan Stankovic
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
| | - Shreyas Bhat
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
- Department of Physics, Université de Montréal, 1375 Avenue Thérèse-Lavoie-Roux, Montréal, QC H3T 1J4, Canada
- Department of Pharmacology and Physiology, Université de Montréal, 2960 Chemin de la Tour, Montréal, QC H3T 1J4, Canada
| | - Sonja Sucic
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
| | - Harald H. Sitte
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
| | - Jae-Won Yang
- Institute of Pharmacology, Center for Physiology and Pharmacology, Medical University of Vienna, Währingerstraße 13A, 1090 Vienna, Austria
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4
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Zhou Q, Liang J, Yang T, Liu J, Li B, Li Y, Fan Z, Wang W, Chen W, Yuan S, Xu M, Xu Q, Luan Z, Xia Z, Zhou P, Huang Y, Chen L. Carfilzomib modulates tumor microenvironment to potentiate immune checkpoint therapy for cancer. EMBO Mol Med 2022; 14:e14502. [PMID: 34898004 PMCID: PMC8749493 DOI: 10.15252/emmm.202114502] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2021] [Revised: 10/31/2021] [Accepted: 11/05/2021] [Indexed: 01/01/2023] Open
Abstract
Impressive clinical benefit is seen in clinic with PD-1 inhibitors on portion of cancer patients. Yet, there remains an urgent need to develop effective synergizers to expand their clinical application. Tumor-associated macrophage (TAM), a type of M2-polarized macrophage, eliminates or suppresses T-cell-mediated anti-tumor responses. Transforming TAMs into M1 macrophages is an attractive strategy of anti-tumor therapy. Here, we conducted a high-throughput screening and found that Carfilzomib potently drove M2 macrophages to express M1 cytokines, phagocytose tumor cells, and present antigens to T cells. Mechanistically, Carfilzomib elicited unfolded protein response (UPR), activated IRE1α to recruit TRAF2, and activated NF-κB to transcribe genes encoding M1 markers in M2 macrophages. In vivo, Carfilzomib effectively rewired tumor microenvironment through reprogramming TAMs into M1-like macrophages and shrank autochthonous lung cancers in transgenic mouse model. More importantly, Carfilzomib synergized with PD-1 antibody to almost completely regress autochthonous lung cancers. Given the safety profiles of Carfilzomib in clinic, our work suggested a potentially immediate application of combinational treatment with Carfilzomib and PD-1 inhibitors for patients with solid tumors.
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Affiliation(s)
- Qian Zhou
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and MOE Key Laboratory of Tumor Molecular BiologyInstitute of Life and Health EngineeringCollege of Life Science and TechnologyJinan UniversityGuangzhouChina
| | - Jinxia Liang
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and MOE Key Laboratory of Tumor Molecular BiologyInstitute of Life and Health EngineeringCollege of Life Science and TechnologyJinan UniversityGuangzhouChina
| | - Tong Yang
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and MOE Key Laboratory of Tumor Molecular BiologyInstitute of Life and Health EngineeringCollege of Life Science and TechnologyJinan UniversityGuangzhouChina
| | - Jin Liu
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and MOE Key Laboratory of Tumor Molecular BiologyInstitute of Life and Health EngineeringCollege of Life Science and TechnologyJinan UniversityGuangzhouChina
| | - Bo Li
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and MOE Key Laboratory of Tumor Molecular BiologyInstitute of Life and Health EngineeringCollege of Life Science and TechnologyJinan UniversityGuangzhouChina
- MOE Key Laboratory of Glucolipid Metabolic DiseasesGuangdong Metabolic Diseases Research Center of Integrated Chinese and Western MedicineCollege of Chinese Medicine ResearchGuangdong Pharmaceutical UniversityGuangzhouChina
| | - Yingchang Li
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and MOE Key Laboratory of Tumor Molecular BiologyInstitute of Life and Health EngineeringCollege of Life Science and TechnologyJinan UniversityGuangzhouChina
| | - Zhenzhen Fan
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and MOE Key Laboratory of Tumor Molecular BiologyInstitute of Life and Health EngineeringCollege of Life Science and TechnologyJinan UniversityGuangzhouChina
| | - Weida Wang
- State Key Laboratory of Oncology in Southern ChinaCollaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Wensheng Chen
- Key Laboratory of Functional Protein Research of Guangdong Higher Education Institutes and MOE Key Laboratory of Tumor Molecular BiologyInstitute of Life and Health EngineeringCollege of Life Science and TechnologyJinan UniversityGuangzhouChina
- Department of OncologyThe First Affiliated HospitalJinan UniversityGuangzhouChina
| | - Sujing Yuan
- State Key Laboratory of Oncology in Southern ChinaCollaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Meng Xu
- Department of OncologyThe First Affiliated HospitalJinan UniversityGuangzhouChina
| | - Qigui Xu
- Translational medicine laboratoryPeople’s Hospital of Yangjiang CityGuangdongChina
| | - Zhidong Luan
- Translational medicine laboratoryPeople’s Hospital of Yangjiang CityGuangdongChina
| | - Zhongjun Xia
- State Key Laboratory of Oncology in Southern ChinaCollaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Penghui Zhou
- State Key Laboratory of Oncology in Southern ChinaCollaborative Innovation Center for Cancer MedicineSun Yat‐sen University Cancer CenterGuangzhouChina
| | - Yadong Huang
- Guangdong Province Key Laboratory of Bioengineering MedicineJinan UniversityGuangzhouChina
| | - Liang Chen
- Department of OncologyThe First Affiliated HospitalJinan UniversityGuangzhouChina
- Guangdong Province Key Laboratory of Bioengineering MedicineJinan UniversityGuangzhouChina
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5
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Liu M, Zaman R, Sawczak V, Periasamy A, Sun F, Zaman K. S-nitrosothiols signaling in cystic fibrosis airways. J Biosci 2021. [DOI: 10.1007/s12038-021-00223-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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6
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Matsuhisa K, Imaizumi K. Loss of Function of Mutant IDS Due to Endoplasmic Reticulum-Associated Degradation: New Therapeutic Opportunities for Mucopolysaccharidosis Type II. Int J Mol Sci 2021; 22:ijms222212227. [PMID: 34830113 PMCID: PMC8618218 DOI: 10.3390/ijms222212227] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Revised: 11/10/2021] [Accepted: 11/10/2021] [Indexed: 12/21/2022] Open
Abstract
Mucopolysaccharidosis type II (MPS II) results from the dysfunction of a lysosomal enzyme, iduronate-2-sulfatase (IDS). Dysfunction of IDS triggers the lysosomal accumulation of its substrates, glycosaminoglycans, leading to mental retardation and systemic symptoms including skeletal deformities and valvular heart disease. Most patients with severe types of MPS II die before the age of 20. The administration of recombinant IDS and transplantation of hematopoietic stem cells are performed as therapies for MPS II. However, these therapies either cannot improve functions of the central nervous system or cause severe side effects, respectively. To date, 729 pathogenetic variants in the IDS gene have been reported. Most of these potentially cause misfolding of the encoded IDS protein. The misfolded IDS mutants accumulate in the endoplasmic reticulum (ER), followed by degradation via ER-associated degradation (ERAD). Inhibition of the ERAD pathway or refolding of IDS mutants by a molecular chaperone enables recovery of the lysosomal localization and enzyme activity of IDS mutants. In this review, we explain the IDS structure and mechanism of activation, and current findings about the mechanism of degradation-dependent loss of function caused by pathogenetic IDS mutation. We also provide a potential therapeutic approach for MPS II based on this loss-of-function mechanism.
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Affiliation(s)
- Koji Matsuhisa
- Correspondence: (K.M.); (K.I.); Tel.: +81-82-257-5131 (K.M.); +81-82-257-5130 (K.I.)
| | - Kazunori Imaizumi
- Correspondence: (K.M.); (K.I.); Tel.: +81-82-257-5131 (K.M.); +81-82-257-5130 (K.I.)
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7
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Shimada BK, Pomozi V, Zoll J, Kuo S, Martin L, Le Saux O. ABCC6, Pyrophosphate and Ectopic Calcification: Therapeutic Solutions. Int J Mol Sci 2021; 22:ijms22094555. [PMID: 33925341 PMCID: PMC8123679 DOI: 10.3390/ijms22094555] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2021] [Revised: 04/20/2021] [Accepted: 04/21/2021] [Indexed: 12/11/2022] Open
Abstract
Pathological (ectopic) mineralization of soft tissues occurs during aging, in several common conditions such as diabetes, hypercholesterolemia, and renal failure and in certain genetic disorders. Pseudoxanthoma elasticum (PXE), a multi-organ disease affecting dermal, ocular, and cardiovascular tissues, is a model for ectopic mineralization disorders. ABCC6 dysfunction is the primary cause of PXE, but also some cases of generalized arterial calcification of infancy (GACI). ABCC6 deficiency in mice underlies an inducible dystrophic cardiac calcification phenotype (DCC). These calcification diseases are part of a spectrum of mineralization disorders that also includes Calcification of Joints and Arteries (CALJA). Since the identification of ABCC6 as the “PXE gene” and the development of several animal models (mice, rat, and zebrafish), there has been significant progress in our understanding of the molecular genetics, the clinical phenotypes, and pathogenesis of these diseases, which share similarities with more common conditions with abnormal calcification. ABCC6 facilitates the cellular efflux of ATP, which is rapidly converted into inorganic pyrophosphate (PPi) and adenosine by the ectonucleotidases NPP1 and CD73 (NT5E). PPi is a potent endogenous inhibitor of calcification, whereas adenosine indirectly contributes to calcification inhibition by suppressing the synthesis of tissue non-specific alkaline phosphatase (TNAP). At present, therapies only exist to alleviate symptoms for both PXE and GACI; however, extensive studies have resulted in several novel approaches to treating PXE and GACI. This review seeks to summarize the role of ABCC6 in ectopic calcification in PXE and other calcification disorders, and discuss therapeutic strategies targeting various proteins in the pathway (ABCC6, NPP1, and TNAP) and direct inhibition of calcification via supplementation by various compounds.
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Affiliation(s)
- Briana K Shimada
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96817, USA
| | - Viola Pomozi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, 1117 Budapest, Hungary
| | - Janna Zoll
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96817, USA
| | - Sheree Kuo
- Department of Pediatrics, Kapi'olani Medical Center for Women and Children, University of Hawaii, Honolulu, HI 96826, USA
| | - Ludovic Martin
- PXE Consultation Center, MAGEC Reference Center for Rare Skin Diseases, Angers University Hospital, 49100 Angers, France
- BNMI, CNRS 6214/INSERM 1083, University Bretagne-Loire, 49100 Angers, France
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu, HI 96817, USA
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Simon S, Aissat A, Degrugillier F, Simonneau B, Fanen P, Arrigo AP. Small Hsps as Therapeutic Targets of Cystic Fibrosis Transmembrane Conductance Regulator Protein. Int J Mol Sci 2021; 22:ijms22084252. [PMID: 33923911 PMCID: PMC8072646 DOI: 10.3390/ijms22084252] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 04/14/2021] [Accepted: 04/16/2021] [Indexed: 12/14/2022] Open
Abstract
Human small heat shock proteins are molecular chaperones that regulate fundamental cellular processes in normal and pathological cells. Here, we have reviewed the role played by HspB1, HspB4 and HspB5 in the context of Cystic Fibrosis (CF), a severe monogenic autosomal recessive disease linked to mutations in Cystic Fibrosis Transmembrane conductance Regulator protein (CFTR) some of which trigger its misfolding and rapid degradation, particularly the most frequent one, F508del-CFTR. While HspB1 and HspB4 favor the degradation of CFTR mutants, HspB5 and particularly one of its phosphorylated forms positively enhance the transport at the plasma membrane, stability and function of the CFTR mutant. Moreover, HspB5 molecules stimulate the cellular efficiency of currently used CF therapeutic molecules. Different strategies are suggested to modulate the level of expression or the activity of these small heat shock proteins in view of potential in vivo therapeutic approaches. We then conclude with other small heat shock proteins that should be tested or further studied to improve our knowledge of CFTR processing.
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Affiliation(s)
- Stéphanie Simon
- INSERM, IMRB, Paris Est Creteil University, F-94010 Creteil, France; (A.A.); (F.D.); (B.S.); (P.F.)
- Correspondence:
| | - Abdel Aissat
- INSERM, IMRB, Paris Est Creteil University, F-94010 Creteil, France; (A.A.); (F.D.); (B.S.); (P.F.)
- Département de Génétique, AP-HP, Henri Mondor Hospital, F-94010 Creteil, France
| | - Fanny Degrugillier
- INSERM, IMRB, Paris Est Creteil University, F-94010 Creteil, France; (A.A.); (F.D.); (B.S.); (P.F.)
| | - Benjamin Simonneau
- INSERM, IMRB, Paris Est Creteil University, F-94010 Creteil, France; (A.A.); (F.D.); (B.S.); (P.F.)
| | - Pascale Fanen
- INSERM, IMRB, Paris Est Creteil University, F-94010 Creteil, France; (A.A.); (F.D.); (B.S.); (P.F.)
- Département de Génétique, AP-HP, Henri Mondor Hospital, F-94010 Creteil, France
| | - André-Patrick Arrigo
- Apoptosis, Cancer and Development Laboratory, Lyon Cancer Research Center, INSERM U1052-CNRS UMR5286, Claude Bernard University Lyon 1, Centre Léon Bérard, F-69008 Lyon, France;
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9
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Molecular Regulation of Canalicular ABC Transporters. Int J Mol Sci 2021; 22:ijms22042113. [PMID: 33672718 PMCID: PMC7924332 DOI: 10.3390/ijms22042113] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 02/15/2021] [Accepted: 02/18/2021] [Indexed: 12/17/2022] Open
Abstract
The ATP-binding cassette (ABC) transporters expressed at the canalicular membrane of hepatocytes mediate the secretion of several compounds into the bile canaliculi and therefore play a key role in bile secretion. Among these transporters, ABCB11 secretes bile acids, ABCB4 translocates phosphatidylcholine and ABCG5/G8 is responsible for cholesterol secretion, while ABCB1 and ABCC2 transport a variety of drugs and other compounds. The dysfunction of these transporters leads to severe, rare, evolutionary biliary diseases. The development of new therapies for patients with these diseases requires a deep understanding of the biology of these transporters. In this review, we report the current knowledge regarding the regulation of canalicular ABC transporters' folding, trafficking, membrane stability and function, and we highlight the role of molecular partners in these regulating mechanisms.
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Bhat S, El-Kasaby A, Freissmuth M, Sucic S. Functional and Biochemical Consequences of Disease Variants in Neurotransmitter Transporters: A Special Emphasis on Folding and Trafficking Deficits. Pharmacol Ther 2020; 222:107785. [PMID: 33310157 PMCID: PMC7612411 DOI: 10.1016/j.pharmthera.2020.107785] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 12/02/2020] [Indexed: 01/30/2023]
Abstract
Neurotransmitters, such as γ-aminobutyric acid, glutamate, acetyl choline, glycine and the monoamines, facilitate the crosstalk within the central nervous system. The designated neurotransmitter transporters (NTTs) both release and take up neurotransmitters to and from the synaptic cleft. NTT dysfunction can lead to severe pathophysiological consequences, e.g. epilepsy, intellectual disability, or Parkinson’s disease. Genetic point mutations in NTTs have recently been associated with the onset of various neurological disorders. Some of these mutations trigger folding defects in the NTT proteins. Correct folding is a prerequisite for the export of NTTs from the endoplasmic reticulum (ER) and the subsequent trafficking to their pertinent site of action, typically at the plasma membrane. Recent studies have uncovered some of the key features in the molecular machinery responsible for transporter protein folding, e.g., the role of heat shock proteins in fine-tuning the ER quality control mechanisms in cells. The therapeutic significance of understanding these events is apparent from the rising number of reports, which directly link different pathological conditions to NTT misfolding. For instance, folding-deficient variants of the human transporters for dopamine or GABA lead to infantile parkinsonism/dystonia and epilepsy, respectively. From a therapeutic point of view, some folding-deficient NTTs are amenable to functional rescue by small molecules, known as chemical and pharmacological chaperones.
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Affiliation(s)
- Shreyas Bhat
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Ali El-Kasaby
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Sonja Sucic
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria.
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11
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Farr CV, El-Kasaby A, Freissmuth M, Sucic S. The Creatine Transporter Unfolded: A Knotty Premise in the Cerebral Creatine Deficiency Syndrome. Front Synaptic Neurosci 2020; 12:588954. [PMID: 33192443 PMCID: PMC7644880 DOI: 10.3389/fnsyn.2020.588954] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2020] [Accepted: 09/18/2020] [Indexed: 12/16/2022] Open
Abstract
Creatine provides cells with high-energy phosphates for the rapid reconstitution of hydrolyzed adenosine triphosphate. The eponymous creatine transporter (CRT1/SLC6A8) belongs to a family of solute carrier 6 (SLC6) proteins. The key role of CRT1 is to translocate creatine across tissue barriers and into target cells, such as neurons and myocytes. Individuals harboring mutations in the coding sequence of the human CRT1 gene develop creatine transporter deficiency (CTD), one of the pivotal underlying causes of cerebral creatine deficiency syndrome. CTD encompasses an array of clinical manifestations, including severe intellectual disability, epilepsy, autism, development delay, and motor dysfunction. CTD is characterized by the absence of cerebral creatine, which implies an indispensable role for CRT1 in supplying the brain cells with creatine. CTD-associated variants dramatically reduce or abolish creatine transport activity by CRT1. Many of these are point mutations that are known to trigger folding defects, leading to the retention of encoded CRT1 proteins in the endoplasmic reticulum and precluding their delivery to the cell surface. Misfolding of several related SLC6 transporters also gives rise to detrimental pathologic conditions in people; e.g., mutations in the dopamine transporter induce infantile parkinsonism/dystonia, while mutations in the GABA transporter 1 cause treatment-resistant epilepsy. In some cases, folding defects are amenable to rescue by small molecules, known as pharmacological and chemical chaperones, which restore the cell surface expression and transport activity of the previously non-functional proteins. Insights from the recent molecular, animal and human case studies of CTD add toward our understanding of this complex disorder and reveal the wide-ranging effects elicited upon CRT1 dysfunction. This grants novel therapeutic prospects for the treatment of patients afflicted with CTD, e.g., modifying the creatine molecule to facilitate CRT1-independent entry into brain cells, or correcting folding-deficient and loss-of-function CTD variants using pharmacochaperones and/or allosteric modulators. The latter justifies a search for additional compounds with a capacity to correct mutation-specific defects.
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Affiliation(s)
| | | | | | - Sonja Sucic
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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12
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Brecker M, Khakhina S, Schubert TJ, Thompson Z, Rubenstein RC. The Probable, Possible, and Novel Functions of ERp29. Front Physiol 2020; 11:574339. [PMID: 33013490 PMCID: PMC7506106 DOI: 10.3389/fphys.2020.574339] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 08/14/2020] [Indexed: 12/16/2022] Open
Abstract
The luminal endoplasmic reticulum (ER) protein of 29 kDa (ERp29) is a ubiquitously expressed cellular agent with multiple critical roles. ERp29 regulates the biosynthesis and trafficking of several transmembrane and secretory proteins, including the cystic fibrosis transmembrane conductance regulator (CFTR), the epithelial sodium channel (ENaC), thyroglobulin, connexin 43 hemichannels, and proinsulin. ERp29 is hypothesized to promote ER to cis-Golgi cargo protein transport via COP II machinery through its interactions with the KDEL receptor; this interaction may facilitate the loading of ERp29 clients into COP II vesicles. ERp29 also plays a role in ER stress (ERS) and the unfolded protein response (UPR) and is implicated in oncogenesis. Here, we review the vast array of ERp29’s clients, its role as an ER to Golgi escort protein, and further suggest ERp29 as a potential target for therapies related to diseases of protein misfolding and mistrafficking.
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Affiliation(s)
- Margaret Brecker
- Cystic Fibrosis Center, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Svetlana Khakhina
- Cystic Fibrosis Center, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Tyler J. Schubert
- Cystic Fibrosis Center, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Zachary Thompson
- Cystic Fibrosis Center, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
| | - Ronald C. Rubenstein
- Cystic Fibrosis Center, The Children’s Hospital of Philadelphia, Philadelphia, PA, United States
- Department of Pediatrics, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, United States
- Division of Allergy and Pulmonary Medicine, Department of Pediatrics, Washington University in St. Louis School of Medicine, St. Louis, MO, United States
- *Correspondence: Ronald C. Rubenstein, ;
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Braun D, Schweizer U. The Protein Translocation Defect of MCT8 L291R Is Rescued by Sodium Phenylbutyrate. Eur Thyroid J 2020; 9:269-280. [PMID: 33088796 PMCID: PMC7548921 DOI: 10.1159/000507439] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 03/24/2020] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION The monocarboxylate transporter 8 (MCT8; SLC16A2) is a specific transporter for thyroid hormones. MCT8 deficiency, formerly known as the Allan-Herndon-Dudley syndrome, is a rare genetic disease that leads to neurological impairments and muscle weakness. Current experimental treatment options rely on thyromimetic agonists that do not depend on MCT8 for cellular uptake. Another approach comes from studies with the chemical chaperone sodium phenylbutyrate (NaPB), which was able to stabilize MCT8 mutants having protein folding defects in vitro. In addition, NaPB is known as a compound that assists with plasma membrane translocation. OBJECTIVE The pathogenic MCT8L291R leads to the same severe neurological impairments found for other MCT8-deficient patients but, unexpectedly, lacks alterations in plasma 3,3',5-triiodothyronine (T3) levels. Here we tried to unravel the underlying mechanism of MCT8 deficiency and tested whether the pathogenic MCT8L291R mutant responds to NaPB treatment. Therefore, we overexpressed the mutant in Madin-Darby canine kidney cells in the human choriocarcinoma cell line JEG1 and in COS7 cells of African green monkey origin. RESULTS In our recent study we describe that the MCT8L291R mutation most likely leads to a translocation defect. The pathogenic mutant is not located at the plasma membrane, but shows overlapping expression with a marker protein of the lysosome. Mutation of the corresponding amino acid in murine Mct8 (Mct8L223R) displays a similar effect on cell surface expression and transport function as seen before for MCT8L291R. NaPB was able to correct the translocation defect of MCT8L291R/Mct8L223R and restored protein function by increasing T3 transport activity. Furthermore, we detected enhanced mRNA levels of wild-type and mutant MCT8/Mct8 after NaPB treatment. The increase in mRNA levels could be an explanation for the positive effect on protein expression and function detected for wild-type MCT8. CONCLUSION NaPB is not only suitable for the treatment of mutations leading to misfolding and protein degradation, but also for a mutant wrongly sorted inside a cell which is otherwise functional.
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Affiliation(s)
- Doreen Braun
- *Doreen Braun, Institut für Biochemie und Molekularbiologie, Medizinische Fakultät, Rheinische Friedrich-Wilhelms-Universität Bonn, Nussallee 11, DE–53115 Bonn (Germany),
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14
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Maulik M, Vasan L, Bose A, Dutta Chowdhury S, Sengupta N, Das Sarma J. Amyloid-β regulates gap junction protein connexin 43 trafficking in cultured primary astrocytes. J Biol Chem 2020; 295:15097-15111. [PMID: 32868453 DOI: 10.1074/jbc.ra120.013705] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 08/06/2020] [Indexed: 11/06/2022] Open
Abstract
Altered expression and function of astroglial gap junction protein connexin 43 (Cx43) has increasingly been associated to neurotoxicity in Alzheimer disease (AD). Although earlier studies have examined the effect of increased β-amyloid (Aβ) on Cx43 expression and function leading to neuronal damage, underlying mechanisms by which Aβ modulates Cx43 in astrocytes remain elusive. Here, using mouse primary astrocyte cultures, we have examined the cellular processes by which Aβ can alter Cx43 gap junctions. We show that Aβ25-35 impairs functional gap junction coupling yet increases hemichannel activity. Interestingly, Aβ25-35 increased the intracellular pool of Cx43 with a parallel decrease in gap junction assembly at the surface. Intracellular Cx43 was found to be partly retained in the endoplasmic reticulum-associated cell compartments. However, forward trafficking of the newly synthesized Cx43 that already reached the Golgi was not affected in Aβ25-35-exposed astrocytes. Supporting this, treatment with 4-phenylbutyrate, a well-known chemical chaperone that improves trafficking of several transmembrane proteins, restored Aβ-induced impaired gap junction coupling between astrocytes. We further show that interruption of Cx43 endocytosis in Aβ25-35-exposed astrocytes resulted in their retention at the cell surface in the form of functional gap junctions indicating that Aβ25-35 causes rapid internalization of Cx43 gap junctions. Additionally, in silico molecular docking suggests that Aβ can bind favorably to Cx43. Our study thus provides novel insights into the cellular mechanisms by which Aβ modulates Cx43 function in astrocytes, the basic understanding of which is vital for the development of alternative therapeutic strategy targeting connexin channels in AD.
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Affiliation(s)
- Mahua Maulik
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India.
| | - Lakshmy Vasan
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Abhishek Bose
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Saikat Dutta Chowdhury
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Neelanjana Sengupta
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Jayasri Das Sarma
- Department of Biological Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
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Dunmore BJ, Yang X, Crosby A, Moore S, Long L, Huang C, Southwood M, Austin ED, Rana A, Upton PD, Morrell NW. 4PBA Restores Signaling of a Cysteine-substituted Mutant BMPR2 Receptor Found in Patients with Pulmonary Arterial Hypertension. Am J Respir Cell Mol Biol 2020; 63:160-171. [PMID: 32255665 DOI: 10.1165/rcmb.2019-0321oc] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Mutations in the gene encoding BMPR2 (bone morphogenetic protein type 2 receptor) are the major cause of heritable pulmonary arterial hypertension (PAH). Point mutations in the BMPR2 ligand-binding domain involving cysteine residues (such as C118W) are causative of PAH and predicted to cause protein misfolding. Using heterologous overexpression systems, we showed previously that these mutations lead to retention of BMPR2 in the endoplasmic reticulum but are partially rescued by chemical chaperones. Here, we sought to determine whether the chemical chaperone 4-phenylbutyrate (4PBA) restores BMPR2 signaling in primary cells and in a knockin mouse harboring a C118W mutation. First, we confirmed dysfunctional BMP signaling in dermal fibroblasts isolated from a family with PAH segregating the BMPR2 C118W mutation. After BMP4 treatment, the induction of downstream signaling targets (Smad1/5, ID1 [inhibitor of DNA binding 1], and ID2) was significantly reduced in C118W mutant cells. Treatment with 4PBA significantly rescued Smad1/5, ID1, and ID2 expression. Pulmonary artery smooth muscle cells isolated from the lungs of heterozygous mice harboring the Bmpr2 C118W mutation exhibited significantly increased proliferation. In the presence of 4PBA, hyperproliferation was dramatically reduced. Furthermore, in vivo, 4PBA treatment of Bmpr2 C118W mice partially rescued Bmpr2 expression, restored downstream signaling, and improved vascular remodeling. These findings demonstrate in primary cells and in a knockin mouse that the repurposed small-molecule chemical chaperone 4PBA might be a promising precision medicine approach to treat PAH in patients with specific subtypes of BMPR2 mutation involving cysteine substitutions in the ligand-binding domain.
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Affiliation(s)
- Benjamin J Dunmore
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - XuDong Yang
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Alexi Crosby
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Stephen Moore
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Lu Long
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Christopher Huang
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Mark Southwood
- Pathology Research, Royal Papworth Hospital NHS Foundation Trust, Cambridge, United Kingdom; and
| | - Eric D Austin
- Department of Pediatrics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Amer Rana
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Paul D Upton
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
| | - Nicholas W Morrell
- Department of Medicine, University of Cambridge School of Clinical Medicine, Addenbrooke's and Royal Papworth Hospitals, Cambridge, United Kingdom
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Inai Y, Ueda K, Matsui ISL, Tajiri M, Minakata S, Wada Y, Ihara Y. Role of C-mannosylation in the secretion of mindin. Biochim Biophys Acta Gen Subj 2020; 1864:129632. [DOI: 10.1016/j.bbagen.2020.129632] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Revised: 05/07/2020] [Accepted: 05/11/2020] [Indexed: 12/30/2022]
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Strub MD, McCray, Jr. PB. Transcriptomic and Proteostasis Networks of CFTR and the Development of Small Molecule Modulators for the Treatment of Cystic Fibrosis Lung Disease. Genes (Basel) 2020; 11:genes11050546. [PMID: 32414011 PMCID: PMC7288469 DOI: 10.3390/genes11050546] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/07/2020] [Accepted: 05/08/2020] [Indexed: 12/18/2022] Open
Abstract
Cystic fibrosis (CF) is a lethal autosomal recessive disease caused by mutations in the CF transmembrane conductance regulator (CFTR) gene. The diversity of mutations and the multiple ways by which the protein is affected present challenges for therapeutic development. The observation that the Phe508del-CFTR mutant protein is temperature sensitive provided proof of principle that mutant CFTR could escape proteosomal degradation and retain partial function. Several specific protein interactors and quality control checkpoints encountered by CFTR during its proteostasis have been investigated for therapeutic purposes, but remain incompletely understood. Furthermore, pharmacological manipulation of many CFTR interactors has not been thoroughly investigated for the rescue of Phe508del-CFTR. However, high-throughput screening technologies helped identify several small molecule modulators that rescue CFTR from proteosomal degradation and restore partial function to the protein. Here, we discuss the current state of CFTR transcriptomic and biogenesis research and small molecule therapy development. We also review recent progress in CFTR proteostasis modulators and discuss how such treatments could complement current FDA-approved small molecules.
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Affiliation(s)
- Matthew D. Strub
- Interdisciplinary Graduate Program in Genetics, The University of Iowa, Iowa City, IA 52242, USA;
- Stead Family Department of Pediatrics, The University of Iowa, Iowa City, IA 52242, USA
| | - Paul B. McCray, Jr.
- Interdisciplinary Graduate Program in Genetics, The University of Iowa, Iowa City, IA 52242, USA;
- Stead Family Department of Pediatrics, The University of Iowa, Iowa City, IA 52242, USA
- Correspondence: ; Tel.: +1-(319)-335-6844
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18
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Wang Z, Zheng S, Gu Y, Zhou L, Lin B, Liu W. 4-PBA Enhances Autophagy by Inhibiting Endoplasmic Reticulum Stress in Recombinant Human Beta Nerve Growth Factor-Induced PC12 cells After Mechanical Injury via PI3K/AKT/mTOR Signaling Pathway. World Neurosurg 2020; 138:e659-e664. [PMID: 32179193 DOI: 10.1016/j.wneu.2020.03.038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 03/04/2020] [Accepted: 03/05/2020] [Indexed: 11/25/2022]
Abstract
OBJECTIVE To investigate mechanism of endoplasmic reticulum (ER) stress-mediated autophagy in spinal cord injury (SCI). METHODS An in vitro model of spinal cord injury (SCI) was established by recombinant human beta nerve growth factor (NGF)-induced PC12 cells. Immunofluorescence was used to detect properties of PC12 cells induced by NGF. Western blot assay was used to detect expressions of the autophagy-related protein microtubule-associated protein 1 light chain 3 (LC3)I/II, the ER stress-related protein (HSPA5/GRP78), as well as the PI3K/AKT/mTOR signaling pathway-related proteins after mechanical injury at different time points. Then the sample assigned into sham, SCI, LY294002, SCI+LY294002, 4-PBA (4-phenylbutyric acid), and SCI+4-PBA groups. The expressions of the LC3I/II and PI3K/AKT/mTOR signaling pathway-related proteins were detected by Western blot assay. RESULTS NGF-induced PC12 cells have neurophysiological characteristics. After administration of the PI3K-specific inhibitor LY294002, phosphorylation levels of AKT and mTOR decreased, and the ratio of LC3II/I was higher in the inhibitor-treated injury group than the simple-injury group. After administration of the ER stress inhibitor 4-PBA, the results were similar to LY294002 group's results compared with SCI group. CONCLUSIONS Our study showed that NGF-induced PC12 cells can induce autophagy and ER stress after mechanical injury. ER stress inhibitor 4-PBA obtained similar effects to PI3K inhibitor LY294002, enhanced autophagy via PI3K/AKT/mTOR signaling pathway.
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Affiliation(s)
- Zhenyu Wang
- Department of Orthopedics, Fujian Medical University Union Hospital, Fuzhou, P.R. China
| | - Shengxiong Zheng
- Department of Orthopedics, Fujian Medical University Union Hospital, Fuzhou, P.R. China
| | - Yang Gu
- Department of Orthopedics, Fujian Medical University Union Hospital, Fuzhou, P.R. China
| | - Linquan Zhou
- Department of Orthopedics, Fujian Medical University Union Hospital, Fuzhou, P.R. China
| | - Bin Lin
- Department of Orthopedics, Fujian Medical University Union Hospital, Fuzhou, P.R. China
| | - Wenge Liu
- Department of Orthopedics, Fujian Medical University Union Hospital, Fuzhou, P.R. China.
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Regulation of CFTR Biogenesis by the Proteostatic Network and Pharmacological Modulators. Int J Mol Sci 2020; 21:ijms21020452. [PMID: 31936842 PMCID: PMC7013518 DOI: 10.3390/ijms21020452] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2019] [Revised: 01/06/2020] [Accepted: 01/08/2020] [Indexed: 12/14/2022] Open
Abstract
Cystic fibrosis (CF) is the most common lethal inherited disease among Caucasians in North America and a significant portion of Europe. The disease arises from one of many mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator, or CFTR. The most common disease-associated allele, F508del, along with several other mutations affect the folding, transport, and stability of CFTR as it transits from the endoplasmic reticulum (ER) to the plasma membrane, where it functions primarily as a chloride channel. Early data demonstrated that F508del CFTR is selected for ER associated degradation (ERAD), a pathway in which misfolded proteins are recognized by ER-associated molecular chaperones, ubiquitinated, and delivered to the proteasome for degradation. Later studies showed that F508del CFTR that is rescued from ERAD and folds can alternatively be selected for enhanced endocytosis and lysosomal degradation. A number of other disease-causing mutations in CFTR also undergo these events. Fortunately, pharmacological modulators of CFTR biogenesis can repair CFTR, permitting its folding, escape from ERAD, and function at the cell surface. In this article, we review the many cellular checkpoints that monitor CFTR biogenesis, discuss the emergence of effective treatments for CF, and highlight future areas of research on the proteostatic control of CFTR.
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20
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Zaman K, Knight J, Hussain F, Cao R, Estabrooks SK, Altawallbeh G, Holloway K, Jafri A, Sawczak V, Li Y, Getsy P, Sun F, Raffay T, Cotton C, Brodsky JL, Periasamy A, Lewis SJ, Gaston B. S-Nitrosylation of CHIP Enhances F508Del-CFTR Maturation. Am J Respir Cell Mol Biol 2019; 61:765-775. [PMID: 31596601 PMCID: PMC6890399 DOI: 10.1165/rcmb.2018-0314oc] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 11/27/2018] [Indexed: 12/13/2022] Open
Abstract
S-nitrosothiols (SNOs) are endogenous signaling molecules that have numerous beneficial effects on the airway via cyclic guanosine monophosphate-dependent and -independent processes. Healthy human airways contain SNOs, but SNO levels are lower in the airways of patients with cystic fibrosis (CF). In this study, we examined the interaction between SNOs and the molecular cochaperone C-terminus Hsc70 interacting protein (CHIP), which is an E3 ubiquitin ligase that targets improperly folded CF transmembrane conductance regulator (CFTR) for subsequent degradation. Both CFBE41o- cells expressing either wild-type or F508del-CFTR and primary human bronchial epithelial cells express CHIP. Confocal microscopy and IP studies showed the cellular colocalization of CFTR and CHIP, and showed that S-nitrosoglutathione inhibits the CHIP-CFTR interaction. SNOs significantly reduced both the expression and activity of CHIP, leading to higher levels of both the mature and immature forms of F508del-CFTR. In fact, SNO inhibition of the function and expression of CHIP not only improved the maturation of CFTR but also increased CFTR's stability at the cell membrane. S-nitrosoglutathione-treated cells also had more S-nitrosylated CHIP and less ubiquitinated CFTR than cells that were not treated, suggesting that the S-nitrosylation of CHIP prevents the ubiquitination of CFTR by inhibiting CHIP's E3 ubiquitin ligase function. Furthermore, the exogenous SNOs S-nitrosoglutathione diethyl ester and S-nitro-N-acetylcysteine increased the expression of CFTR at the cell surface. After CHIP knockdown with siRNA duplexes specific for CHIP, F508del-CFTR expression increased at the cell surface. We conclude that SNOs effectively reduce CHIP-mediated degradation of CFTR, resulting in increased F508del-CFTR expression on airway epithelial cell surfaces. Together, these findings indicate that S-nitrosylation of CHIP is a novel mechanism of CFTR correction, and we anticipate that these insights will allow different SNOs to be optimized as agents for CF therapy.
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Affiliation(s)
- Khalequz Zaman
- Pediatric Pulmonology Division, Department of Pediatrics, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - Julia Knight
- Pediatric Pulmonology Division, Department of Pediatrics, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - Faraaz Hussain
- Pediatric Pulmonology Division, Department of Pediatrics, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - Ruofan Cao
- W. M. Keck Center for Cellular Imaging, University of Virginia, Charlottesville, Virginia
| | - Samuel K. Estabrooks
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Ghaith Altawallbeh
- Pediatric Pulmonology Division, Department of Pediatrics, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - Kristopher Holloway
- Pediatric Pulmonology Division, Department of Pediatrics, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - Anjum Jafri
- Pediatric Pulmonology Division, Department of Pediatrics, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - Victoria Sawczak
- Pediatric Pulmonology Division, Department of Pediatrics, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - Yuejin Li
- Pediatric Pulmonology Division, Department of Pediatrics, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - Paulina Getsy
- Pediatric Pulmonology Division, Department of Pediatrics, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - Fei Sun
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Thomas Raffay
- Pediatric Pulmonology Division, Department of Pediatrics, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - Calvin Cotton
- Pediatric Pulmonology Division, Department of Pediatrics, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - Jeffrey L. Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania; and
| | - Ammasi Periasamy
- W. M. Keck Center for Cellular Imaging, University of Virginia, Charlottesville, Virginia
| | - Stephen J. Lewis
- Pediatric Pulmonology Division, Department of Pediatrics, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, Ohio
| | - Benjamin Gaston
- Pediatric Pulmonology Division, Department of Pediatrics, University Hospitals Rainbow Babies and Children’s Hospital, Cleveland, Ohio
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Bonam SR, Ruff M, Muller S. HSPA8/HSC70 in Immune Disorders: A Molecular Rheostat that Adjusts Chaperone-Mediated Autophagy Substrates. Cells 2019; 8:E849. [PMID: 31394830 PMCID: PMC6721745 DOI: 10.3390/cells8080849] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Revised: 08/02/2019] [Accepted: 08/05/2019] [Indexed: 12/24/2022] Open
Abstract
HSPA8/HSC70 is a molecular chaperone involved in a wide variety of cellular processes. It plays a crucial role in protein quality control, ensuring the correct folding and re-folding of selected proteins, and controlling the elimination of abnormally-folded conformers and of proteins daily produced in excess in our cells. HSPA8 is a crucial molecular regulator of chaperone-mediated autophagy, as a detector of substrates that will be processed by this specialized autophagy pathway. In this review, we shortly summarize its structure and overall functions, dissect its implication in immune disorders, and list the known pharmacological tools that modulate its functions. We also exemplify the interest of targeting HSPA8 to regulate pathological immune dysfunctions.
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Affiliation(s)
- Srinivasa Reddy Bonam
- Neuroimmunology & peptide therapy, Biotechnology and cell signaling, CNRS-University of Strasbourg, Illkirch 67412, France/Laboratory of excellence Medalis, 67000 Strasbourg, France
| | - Marc Ruff
- Biologie Structurale Intégrative, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, 67404 Strasbourg, France
| | - Sylviane Muller
- Neuroimmunology & peptide therapy, Biotechnology and cell signaling, CNRS-University of Strasbourg, Illkirch 67412, France/Laboratory of excellence Medalis, 67000 Strasbourg, France.
- University of Strasbourg Institute for Advanced Study (USIAS), 67000 Strasbourg, France.
- Fédération Hospitalo-Universitaire (FHU) OMICARE, Fédération de Médecine Translationnelle de Strasbourg (FMTS), Strasbourg University, 67000 Strasbourg, France.
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How to rescue misfolded SERT, DAT and NET: targeting conformational intermediates with atypical inhibitors and partial releasers. Biochem Soc Trans 2019; 47:861-874. [PMID: 31064865 PMCID: PMC6599159 DOI: 10.1042/bst20180512] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/12/2019] [Accepted: 04/12/2019] [Indexed: 11/17/2022]
Abstract
Point mutations in the coding sequence for solute carrier 6 (SLC6) family members result in clinically relevant disorders, which are often accounted for by a loss-of-function phenotype. In many instances, the mutated transporter is not delivered to the cell surface because it is retained in the endoplasmic reticulum (ER). The underlying defect is improper folding of the transporter and is the case for many of the known dopamine transporter mutants. The monoamine transporters, i.e. the transporters for norepinephrine (NET/SLC6A2), dopamine (DAT/SLC6A3) and serotonin (SERT/SLC6A4), have a rich pharmacology; hence, their folding-deficient mutants lend themselves to explore the concept of pharmacological chaperoning. Pharmacochaperones are small molecules, which bind to folding intermediates with exquisite specificity and scaffold them to a folded state, which is exported from the ER and delivered to the cell surface. Pharmacochaperoning of mutant monoamine transporters, however, is not straightforward: ionic conditions within the ER are not conducive to binding of most typical monoamine transporter ligands. A collection of compounds exists, which are classified as atypical ligands because they trap monoamine transporters in unique conformational states. The atypical binding mode of some DAT inhibitors has been linked to their anti-addictive action. Here, we propose that atypical ligands and also compounds recently classified as partial releasers can serve as pharmacochaperones.
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Zinc Attenuates the Cytotoxicity of Some Stimuli by Reducing Endoplasmic Reticulum Stress in Hepatocytes. Int J Mol Sci 2019; 20:ijms20092192. [PMID: 31058829 PMCID: PMC6540033 DOI: 10.3390/ijms20092192] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2019] [Revised: 04/28/2019] [Accepted: 05/02/2019] [Indexed: 01/01/2023] Open
Abstract
Zinc is an essential trace element and plays critical roles in cellular integrity and biological functions. Excess copper induced both oxidative stress and endoplasmic reticulum (ER) stress in liver-derived cultured cells. Excess copper also induced impairment of autophagic flux at the step of autophagosome–lysosome fusion, as well as Mallory–Denk body (MDB)-like inclusion body formation. Zinc ameliorated excess copper-induced impairment of autophagic flux and MDB-like inclusion body formation via the maintenance of ER homeostasis. Furthermore, zinc also ameliorated free fatty acid-induced impairment of autophagic flux. These results indicate that zinc may be able to protect hepatocytes from various ER stress-related conditions.
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Rescue by 4-phenylbutyrate of several misfolded creatine transporter-1 variants linked to the creatine transporter deficiency syndrome. Neuropharmacology 2019; 161:107572. [PMID: 30885608 DOI: 10.1016/j.neuropharm.2019.03.015] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 03/07/2019] [Accepted: 03/11/2019] [Indexed: 12/15/2022]
Abstract
Diseases arising from misfolding of SLC6 transporters have been reported over recent years, e.g. folding-deficient mutants of the dopamine transporter and of the glycine transporter-2 cause infantile/juvenile Parkinsonism dystonia and hyperekplexia, respectively. Mutations in the coding sequence of the human creatine transporter-1 (hCRT-1/SLC6A8) gene result in a creatine transporter deficiency syndrome, which varies in its clinical manifestation from epilepsy, mental retardation, autism, development delay and motor dysfunction to gastrointestinal symptoms. Some of the mutations in hCRT-1 occur at residues, which are highly conserved across the SLC6 family. Here, we examined 16 clinically relevant hCRT-1 variants to verify the conjecture that they were misfolded and that this folding defect was amenable to correction. Confocal microscopy imaging revealed that the heterologously expressed YFP-tagged mutant CRTs were trapped in the endoplasmic reticulum (ER), co-localised with the ER-resident chaperone calnexin. In contrast, the wild type hCRT-1 reached the plasma membrane. Preincubation of transiently transfected HEK293 cells with the chemical chaperone 4-phenylbutyrate (4-PBA) restored ER export and surface expression of as well as substrate uptake by several folding-deficient CRT-1 mutants. A representative mutant (hCRT-1-P544L) was expressed in rat primary hippocampal neurons to verify pharmacochaperoning in a target cell: 4-PBA promoted the delivery of hCRT-1-P544L to the neurite extensions. These observations show that several folding-deficient hCRT-1 mutants can be rescued. This proof-of-principle justifies the search for additional pharmacochaperones to restore folding of 4PBA-unresponsive hCRT-1 mutants. Finally, 4-PBA is an approved drug in paediatric use: this provides a rationale for translating the current insights into clinical trials. This article is part of the issue entitled 'Special Issue on Neurotransmitter Transporters'.
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Pranke I, Golec A, Hinzpeter A, Edelman A, Sermet-Gaudelus I. Emerging Therapeutic Approaches for Cystic Fibrosis. From Gene Editing to Personalized Medicine. Front Pharmacol 2019; 10:121. [PMID: 30873022 PMCID: PMC6400831 DOI: 10.3389/fphar.2019.00121] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Accepted: 01/31/2019] [Indexed: 12/13/2022] Open
Abstract
An improved understanding of the cystic fibrosis (CF) transmembrane conductance regulator (CFTR) protein structure and the consequences of CFTR gene mutations have allowed the development of novel therapies targeting specific defects underlying CF. Some strategies are mutation specific and have already reached clinical development; some strategies include a read-through of the specific premature termination codons (read-through therapies, nonsense mediated decay pathway inhibitors for Class I mutations); correction of CFTR folding and trafficking to the apical plasma membrane (correctors for Class II mutations); and an increase in the function of CFTR channel (potentiators therapy for Class III mutations and any mutant with a residual function located at the membrane). Other therapies that are in preclinical development are not mutation specific and include gene therapy to edit the genome and stem cell therapy to repair the airway tissue. These strategies that are directed at the basic CF defects are now revolutionizing the treatment for patients and should positively impact their survival rates.
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Affiliation(s)
- Iwona Pranke
- INSERM U 1151, Institut Necker Enfants Malades, Université Paris Descartes, Paris, France
| | - Anita Golec
- INSERM U 1151, Institut Necker Enfants Malades, Université Paris Descartes, Paris, France
| | - Alexandre Hinzpeter
- INSERM U 1151, Institut Necker Enfants Malades, Université Paris Descartes, Paris, France
| | - Aleksander Edelman
- INSERM U 1151, Institut Necker Enfants Malades, Université Paris Descartes, Paris, France
| | - Isabelle Sermet-Gaudelus
- INSERM U 1151, Institut Necker Enfants Malades, Université Paris Descartes, Paris, France.,Centre de Référence Maladie Rare, Mucoviscidose et Maladies de CFTR, Paris, France.,Faculté de Médecine, Université Paris Descartes, Paris, France
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26
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Li H, Wen W, Xu H, Wu H, Xu M, Frank JA, Luo J. 4-Phenylbutyric Acid Protects Against Ethanol-Induced Damage in the Developing Mouse Brain. Alcohol Clin Exp Res 2018; 43:69-78. [PMID: 30403409 DOI: 10.1111/acer.13918] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 10/27/2018] [Indexed: 12/18/2022]
Abstract
BACKGROUND Ethanol (EtOH) exposure during pregnancy may result in fetal alcohol spectrum disorders (FASD). One of the most deleterious consequences of EtOH exposure is neuronal loss in the developing brain. Previously, we showed that EtOH exposure induced neuroapoptosis in the brain of postnatal day 4 (PD4) mice but not PD12 mice. This differential susceptibility may result from an insufficient cellular stress response system such as unfolded protein response (also known as endoplasmic reticulum [ER] stress) in PD4 mice. In this study, we compared the effect of EtOH on ER stress in PD4 and PD12 mice and determined whether the inhibition of ER stress could protect the developing brain against EtOH damage. METHODS We used a third-trimester equivalent mouse model of FASD. PD4 and PD12 C57BL/6 mice were subcutaneously injected with saline (control), EtOH, EtOH plus 4-phenylbutyric acid (4-PBA), a chemical chaperone known as ER stress inhibitor, and 4-PBA alone. The expression of apoptosis marker, ER stress markers, and markers for glial cell activation was examined in the cerebral cortex. RESULTS EtOH induced neuroapoptosis and increased the expression of ER stress markers, such as activating transcription factor 6, 78-kDa glucose-regulated protein, inositol-requiring enzyme 1α, mesencephalic astrocyte-derived neurotrophic factor, and caspase-12 in PD4 but not PD12 mice. EtOH exposure also activated microglia and astrocytes. Interestingly, treatment with 4-PBA attenuated EtOH-induced neuroapoptosis. Moreover, 4-PBA inhibited the expression of the aforementioned ER stress markers and EtOH-induced glial activation in PD4 mice. CONCLUSIONS ER stress plays an important role in EtOH-induced damage to the developing brain. Inhibition of ER stress is neuroprotective and may provide a new therapeutic strategy for treating FASD.
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Affiliation(s)
- Hui Li
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, Kentucky
| | - Wen Wen
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, Kentucky
| | - Hong Xu
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, Kentucky
| | - Huaxun Wu
- Institute of Clinical Pharmacology, Key Laboratory of Anti-Inflammatory and Immune Medicine, Anhui Medical University, Hefei, China
| | - Mei Xu
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, Kentucky
| | - Jacqueline A Frank
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, Kentucky
| | - Jia Luo
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, Kentucky.,Lexington VA Health Care System, Research & Development, Lexington, Kentucky
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27
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Tao YX, Conn PM. Pharmacoperones as Novel Therapeutics for Diverse Protein Conformational Diseases. Physiol Rev 2018; 98:697-725. [PMID: 29442594 DOI: 10.1152/physrev.00029.2016] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
After synthesis, proteins are folded into their native conformations aided by molecular chaperones. Dysfunction in folding caused by genetic mutations in numerous genes causes protein conformational diseases. Membrane proteins are more prone to misfolding due to their more intricate folding than soluble proteins. Misfolded proteins are detected by the cellular quality control systems, especially in the endoplasmic reticulum, and proteins may be retained there for eventual degradation by the ubiquitin-proteasome system or through autophagy. Some misfolded proteins aggregate, leading to pathologies in numerous neurological diseases. In vitro, modulating mutant protein folding by altering molecular chaperone expression can ameliorate some misfolding. Some small molecules known as chemical chaperones also correct mutant protein misfolding in vitro and in vivo. However, due to their lack of specificity, their potential as therapeutics is limited. Another class of compounds, known as pharmacological chaperones (pharmacoperones), binds with high specificity to misfolded proteins, either as enzyme substrates or receptor ligands, leading to decreased folding energy barriers and correction of the misfolding. Because many of the misfolded proteins are misrouted but do not have defects in function per se, pharmacoperones have promising potential in advancing to the clinic as therapeutics, since correcting routing may ameliorate the underlying mechanism of disease. This review will comprehensively summarize this exciting area of research, surveying the literature from in vitro studies in cell lines to transgenic animal models and clinical trials in several protein misfolding diseases.
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Affiliation(s)
- Ya-Xiong Tao
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University , Auburn, Alabama ; and Departments of Internal Medicine and Cell Biology, Texas Tech University Health Science Center , Lubbock, Texas
| | - P Michael Conn
- Department of Anatomy, Physiology and Pharmacology, College of Veterinary Medicine, Auburn University , Auburn, Alabama ; and Departments of Internal Medicine and Cell Biology, Texas Tech University Health Science Center , Lubbock, Texas
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28
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Kumari N, Kumar A, Thapa BR, Modi M, Pal A, Prasad R. Characterization of mutation spectrum and identification of novel mutations in ATP7B gene from a cohort of Wilson disease patients: Functional and therapeutic implications. Hum Mutat 2018; 39:1926-1941. [PMID: 30120852 DOI: 10.1002/humu.23614] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 08/09/2018] [Accepted: 08/13/2018] [Indexed: 12/13/2022]
Abstract
Wilson disease (WD), a copper metabolism disorder, occurs due to the presence of mutations in the gene encoding ATP7B, a protein that primarily facilitates hepatic copper excretion. A better understanding of spectrum and functional significance of ATP7B variants is critical to formulating targeted and personalized therapies. Henceforth, we screened and sequenced 21 exons of ATP7B gene from 50 WD patients and 60 healthy subjects. We identified 28 variants comprising, seven novels in 20% alleles, while eight variations affecting 23% alleles were first time reported in Indian cohort. The c.813C>A, p.(Cys271*) (10%) was the most frequent mutation. Bioinformatics analysis revealed five of seven novel variants viz. c.1600C>A, p.(Pro534Thr); c.1616C>A, p.(Pro539His); c.1924G>T, p.(Asp642Tyr); c.2168G>C, p.(Arg723Thr); c.2174G>C, p.(Arg725Thr) resulted in protein misfolding. Sequence conservation analysis of ATP7B regions containing novel variants documented an evolutionarily conserved nature. Functional analysis of these novel variants in five different cell lines lacking inherent ATP7B expression demonstrated sensitivity to CuCl2 -treatment, experiencing augmented cellular copper retention and decreased copper excretion as well as ceruloplasmin secretion to that of wildtype-ATP7B expressing cells. Interestingly, pharmacological chaperone 4-phenylbutyrate, a clinically approved compound, partially restored protein function of ATP7B mutants. These findings might enable novel treatment strategies in WD by clinically enhancing the protein expression of mutant ATP7B with residual copper export activity.
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Affiliation(s)
- Niti Kumari
- Department of Biochemistry, PGIMER, Chandigarh, India
| | - Aman Kumar
- Department of Biochemistry, PGIMER, Chandigarh, India
| | - Babu Ram Thapa
- Department of Paediatrics Gastroenterology, PGIMER, Chandigarh, India
| | - Manish Modi
- Department of Neurology, PGIMER, Chandigarh, India
| | - Arnab Pal
- Department of Biochemistry, PGIMER, Chandigarh, India
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29
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Shutdown of ER-associated degradation pathway rescues functions of mutant iduronate 2-sulfatase linked to mucopolysaccharidosis type II. Cell Death Dis 2018; 9:808. [PMID: 30042467 PMCID: PMC6057917 DOI: 10.1038/s41419-018-0871-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 07/04/2018] [Accepted: 07/10/2018] [Indexed: 01/04/2023]
Abstract
Mucopolysaccharidosis type II (MPS II), also known as Hunter syndrome, is a devastating progressive disease caused by mutations in the iduronate 2-sulfatase (IDS) gene. IDS is one of the sulfatase enzymes required for lysosomal degradation of glycosaminoglycans. Mutant proteins linked to diseases are often prone to misfolding. These misfolded proteins accumulate in the endoplasmic reticulum (ER) and are degraded by the ubiquitin–proteasome pathway (ER-associated degradation (ERAD)). The decreased enzyme activities of IDS mutants may be due to accelerated degradation by ERAD. However, intracellular dynamics including degradation of IDS mutants is unexplored. In this report, we examined biochemical and biological characteristics of wild-type (WT) IDS and IDS mutants expressed in HeLa cells. IDS was shown to be glycosylated in the ER and Golgi apparatus and proteolytically cleaved to generate the mature forms in the Golgi apparatus. The mature WT IDS was translocated to the lysosome. In contrast, all IDS mutants we examined were found to accumulate in the ER and could not efficiently translocate to the lysosome. Accumulated IDS mutants in the ER were ubiquitinated by ERAD-related ubiquitin E3 ligase HRD1 followed by degradation via ERAD. Suppressed degradation of ‘attenuated’ mutant A85T IDS (the late-onset form of MPS II) by inhibiting ERAD components improved translocation to the lysosome and its activities. Our novel findings provide alternative targets to current principal therapies for MPS II. These perspectives provide a potenti al framework to develop fundamental therapeutic strategies and agents.
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30
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Kaur B, Bhat A, Chakraborty R, Adlakha K, Sengupta S, Roy S, Chakraborty K. Proteomic profile of 4-PBA treated human neuronal cells during ER stress. Mol Omics 2018; 14:53-63. [PMID: 29570205 DOI: 10.1039/c7mo00114b] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Perturbations affecting the homoeostasis of endoplasmic reticulum (ER) activate an adaptive signaling known as the unfolded protein response or UPR. Many studies have reported the association between neurological disorders and ER stress. Decreasing ER stress may therefore aid in therapeutic control of neuronal diseases. Sodium 4-phenylbutyrate (4-PBA), a small molecule, has been shown to alleviate ER stress and various neurological diseases, but the mechanistic basis of its action is not well understood. Using an iTRAQ based LC-MS technique we have delineated the effect of 4-PBA on the proteome of human neuroblastoma cells (SK-N-SH) during Tunicamycin-induced ER stress. The proteomic profile of 4-PBA-treated cells revealed that 4-PBA does not alter the cellular proteome to adapt towards ER stress. However, it can alleviate both the toxicity and proteomic alterations, induced by an ER stress inducer. Hence, the therapeutic effect of 4-PBA is primarily due to its ability to resolve ER stress rather than its ability to alter the expression of proteins required for maintaining ER proteostasis. Thus, we posit here that 4-PBA acts as an authentic chemical chaperone by aiding protein folding in the ER.
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Affiliation(s)
- Bhavneet Kaur
- Genomics and Molecular Medicine, CSIR-IGIB, Mathura Road, New Delhi, India.
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31
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Crosstalk between endoplasmic reticulum stress and oxidative stress in schizophrenia: The dawn of new therapeutic approaches. Neurosci Biobehav Rev 2017; 83:589-603. [DOI: 10.1016/j.neubiorev.2017.08.025] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 08/09/2017] [Accepted: 08/30/2017] [Indexed: 01/15/2023]
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32
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Kuo CY, Lin CH, Hsu T. VHL Inactivation in Precancerous Kidney Cells Induces an Inflammatory Response via ER Stress-Activated IRE1 α Signaling. Cancer Res 2017; 77:3406-3416. [PMID: 28533271 DOI: 10.1158/0008-5472.can-16-3196] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 04/06/2017] [Accepted: 05/09/2017] [Indexed: 11/16/2022]
Abstract
Mutations and epigenetic inactivation of the tumor suppressor gene von Hippel-Lindau (VHL) are major causes of clear-cell renal cell carcinoma (ccRCC) that may originate from chronic inflammation. However, the role of VHL loss of function in the development of ccRCC via inflammation remains poorly understood. VHL-mutant cells exhibit metabolic abnormalities that can cause chronic endoplasmic reticulum (ER) stress and unfolded protein response. We hypothesize that unresolved ER stress induces the inflammatory responses observed in ccRCC. ER stress markers including BiP and XBP1s were significantly increased in cultured and primary VHL loss-of-function kidney cells. In epithelial cells, the kinase activity of IRE1α was required for the induction of NF-κB and JNK and for the recruitment of macrophages. IRE1α kinase activity was also important for the development of fibrotic phenotype in conditional Vhlh knockout mice. Our results offer insights into the therapeutic potential against ccRCC development by relieving metabolic stress. Such cancer prevention strategy may be critical for high-risk cohorts such as the familial VHL disease patients. Cancer Res; 77(13); 3406-16. ©2017 AACR.
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Affiliation(s)
- Chan-Yen Kuo
- Department of Biomedical Sciences and Engineering, National Central University, Jhongli, Taiwan.,Institute of Systems Biology and Bioinformatics, National Central University, Jhongli, Taiwan
| | - Chih-Hung Lin
- Department of Biomedical Sciences and Engineering, National Central University, Jhongli, Taiwan.,Department of Internal Medicine, Cathay General Hospital, Taipei, Taiwan
| | - Tien Hsu
- Department of Biomedical Sciences and Engineering, National Central University, Jhongli, Taiwan. .,Institute of Systems Biology and Bioinformatics, National Central University, Jhongli, Taiwan.,Department of Medicine, Boston University School of Medicine, Boston, Massachusetts
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33
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BMP type II receptor as a therapeutic target in pulmonary arterial hypertension. Cell Mol Life Sci 2017; 74:2979-2995. [PMID: 28447104 PMCID: PMC5501910 DOI: 10.1007/s00018-017-2510-4] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 03/09/2017] [Accepted: 03/17/2017] [Indexed: 12/30/2022]
Abstract
Pulmonary arterial hypertension (PAH) is a chronic disease characterized by a progressive elevation in mean pulmonary arterial pressure. This occurs due to abnormal remodeling of small peripheral lung vasculature resulting in progressive occlusion of the artery lumen that eventually causes right heart failure and death. The most common cause of PAH is inactivating mutations in the gene encoding a bone morphogenetic protein type II receptor (BMPRII). Current therapeutic options for PAH are limited and focused mainly on reversal of pulmonary vasoconstriction and proliferation of vascular cells. Although these treatments can relieve disease symptoms, PAH remains a progressive lethal disease. Emerging data suggest that restoration of BMPRII signaling in PAH is a promising alternative that could prevent and reverse pulmonary vascular remodeling. Here we will focus on recent advances in rescuing BMPRII expression, function or signaling to prevent and reverse pulmonary vascular remodeling in PAH and its feasibility for clinical translation. Furthermore, we summarize the role of described miRNAs that directly target the BMPR2 gene in blood vessels. We discuss the therapeutic potential and the limitations of promising new approaches to restore BMPRII signaling in PAH patients. Different mutations in BMPR2 and environmental/genetic factors make PAH a heterogeneous disease and it is thus likely that the best approach will be patient-tailored therapies.
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34
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Hegde RN, Subramanian A, Pothukuchi P, Parashuraman S, Luini A. Rare ER protein misfolding-mistrafficking disorders: Therapeutic developments. Tissue Cell 2017; 49:175-185. [PMID: 28222887 DOI: 10.1016/j.tice.2017.02.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2016] [Revised: 02/02/2017] [Accepted: 02/04/2017] [Indexed: 12/16/2022]
Abstract
The presence of a functional protein at the appropriate location in the cell is the result of the processes of transcription, translation, folding and trafficking to the correct destination. There are numerous diseases that are caused by protein misfolding, mainly due to mutations in the respective gene. The consequences of this misfolding may be that proteins effectively lose their function, either by being removed by the cellular quality control machinery or by accumulating at the incorrect intracellular or extracellular location. A number of mutations that lead to protein misfolding and affect trafficking to the final destination, e.g. Cystic fibrosis, Wilson's disease, and Progressive Familial Intrahepatic 1 cholestasis, result in proteins that retain partial function if their folding and trafficking is restored either by molecular or pharmacological means. In this review, we discuss several mutant proteins within this class of misfolding diseases and provide an update on the status of molecular and therapeutic developments and potential therapeutic strategies being developed to counter these diseases.
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Affiliation(s)
| | - Advait Subramanian
- Institute of Protein Biochemistry, National Research Council, Naples, Italy
| | | | | | - Alberto Luini
- Institute of Protein Biochemistry, National Research Council, Naples, Italy; Istituto di Ricovero e Cura a Carattere Scientifico SDN, Naples, Italy
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35
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Freissmuth M, Stockner T, Sucic S. SLC6 Transporter Folding Diseases and Pharmacochaperoning. Handb Exp Pharmacol 2017; 245:249-270. [PMID: 29086036 DOI: 10.1007/164_2017_71] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The human genome encodes 19 genes of the solute carrier 6 (SLC6) family; non-synonymous changes in the coding sequence give rise to mutated transporters, which are misfolded and thus cause diseases in the affected individuals. Prominent examples include mutations in the transporters for dopamine (DAT, SLC6A3), for creatine (CT1, SLC6A8), and for glycine (GlyT2, SLC6A5), which result in infantile dystonia, mental retardation, and hyperekplexia, respectively. Thus, there is an obvious unmet medical need to identify compounds, which can remedy the folding deficit. The pharmacological correction of folding defects was originally explored in mutants of the serotonin transporter (SERT, SLC6A4), which were created to study the COPII-dependent export from the endoplasmic reticulum. This led to the serendipitous discovery of the pharmacochaperoning action of ibogaine. Ibogaine and its metabolite noribogaine also rescue several disease-relevant mutants of DAT. Because the pharmacology of DAT and SERT is exceptionally rich, it is not surprising that additional compounds have been identified, which rescue folding-deficient mutants. These compounds are not only of interest for restoring DAT function in the affected children. They are also likely to serve as useful tools to interrogate the folding trajectory of the transporter. This is likely to initiate a virtuous cycle: if the principles underlying folding of SLC6 transporters are understood, the design of pharmacochaperones ought to be facilitated.
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Affiliation(s)
- Michael Freissmuth
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria.
| | - Thomas Stockner
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Sonja Sucic
- Institute of Pharmacology and the Gaston H. Glock Research Laboratories for Exploratory Drug Development, Center of Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
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36
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The biology of the ABCA3 lipid transporter in lung health and disease. Cell Tissue Res 2016; 367:481-493. [PMID: 28025703 DOI: 10.1007/s00441-016-2554-z] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 11/29/2016] [Indexed: 01/10/2023]
Abstract
The lipid transporter, ATP-binding cassette class A3 (ABCA3), is a highly conserved multi-membrane-spanning protein that plays a critical role in the regulation of pulmonary surfactant homeostasis. Mutations in ABCA3 have been increasingly recognized as one of the causes of inherited pulmonary diseases. These monogenic disorders produce familial lung abnormalities with pathological presentations ranging from neonatal surfactant-deficiency-induced respiratory failure to childhood or adult diffuse parenchymal lung diseases for which specific treatment modalities remain limited. More than 200 ABCA3 mutations have been reported to date with approximately three quarters of patients presenting as compound heterozygotes. Recent advances in our understanding of the molecular basis underlying normal ABCA3 biosynthesis and processing and of the mechanisms of alveolar epithelial cell dysregulation caused by the expression of its mutant forms are beginning to emerge. These insights and the role of environmental factors and modifier genes are discussed in the context of the considerable variability in disease presentation observed in patients with identical ABCA3 gene mutations. Moreover, the opportunities afforded by an enhanced understanding of ABCA3 biology for targeted therapeutic strategies are addressed.
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Ran Y, Thibodeau PH. Stabilization of Nucleotide Binding Domain Dimers Rescues ABCC6 Mutants Associated with Pseudoxanthoma Elasticum. J Biol Chem 2016; 292:1559-1572. [PMID: 27994049 DOI: 10.1074/jbc.m116.759811] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 12/08/2016] [Indexed: 12/31/2022] Open
Abstract
ABC transporters are polytopic membrane proteins that utilize ATP binding and hydrolysis to facilitate transport across biological membranes. Forty-eight human ABC transporters have been identified in the genome, and the majority of these are linked to heritable disease. Mutations in the ABCC6 (ATP binding cassette transporter C6) ABC transporter are associated with pseudoxanthoma elasticum, a disease of altered elastic properties in multiple tissues. Although ∼200 mutations have been identified in pseudoxanthoma elasticum patients, the underlying structural defects associated with the majority of these are poorly understood. To evaluate the structural consequences of these missense mutations, a combination of biophysical and cell biological approaches were applied to evaluate the local and global folding and assembly of the ABCC6 protein. Structural and bioinformatic analyses suggested that a cluster of mutations, representing roughly 20% of the patient population with identified missense mutations, are located in the interface between the transmembrane domain and the C-terminal nucleotide binding domain. Biochemical and cell biological analyses demonstrate these mutations influence multiple steps in the biosynthetic pathway, minimally altering local domain structure but adversely impacting ABCC6 assembly and trafficking. The differential impacts on local and global protein structure are consistent with hierarchical folding and assembly of ABCC6. Stabilization of specific domain-domain interactions via targeted amino acid substitution in the catalytic site of the C-terminal nucleotide binding domain restored proper protein trafficking and cell surface localization of multiple biosynthetic mutants. This rescue provides a specific mechanism by which chemical chaperones could be developed for the correction of ABCC6 biosynthetic defects.
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Affiliation(s)
- Yanchao Ran
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania 15219
| | - Patrick H Thibodeau
- From the Department of Microbiology and Molecular Genetics, University of Pittsburgh, School of Medicine, Pittsburgh, Pennsylvania 15219.
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38
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Sucic S, Kasture A, Mazhar Asjad HM, Kern C, El-Kasaby A, Freissmuth M. When transporters fail to be transported: how to rescue folding-deficient SLC6 transporters. ACTA ACUST UNITED AC 2016; 1:34-40. [PMID: 28405636 PMCID: PMC5386142 DOI: 10.29245/2572.942x/2016/9.1098] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The human dopamine transporter (hDAT) belongs to the solute carrier 6 (SLC6) gene family. Point mutations in hDAT (SLC6A3) have been linked to a syndrome of dopamine transporter deficiency or infantile dystonia/parkinsonism. The mutations impair DAT folding, causing retention of variant DATs in the endoplasmic reticulum and subsequently impair transport activity. The folding trajectory of DAT itself is not understood, though many insights have been gained from studies of folding-deficient mutants of the closely related serotonin transporter (SERT); i.e. their functional rescue by pharmacochaperoning with (nor)ibogaine or heat-shock protein inhibitors. We recently provided a proof-of-principle that folding-deficits in DAT are amenable to rescue in vitro and in vivo. As a model we used the Drosophila melanogaster DAT mutant dDAT-G108Q, which phenocopies the fumin/sleepless DAT-knockout. Treatment with noribogaine and/or HSP70 inhibitor pifithrin-μ restored folding of, and dopamine transport by, dDAT-G108Q, its axonal delivery and normal sleep time in mutant flies. The possibility of functional rescue of misfolded DATs in living flies by pharmacochaperoning grants new therapeutic prospects in the remedy of folding diseases, not only in hDAT, but also in other SLC6 transporters, in particular mutants of the creatine transporter-1, which give rise to X-linked mental retardation.
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Affiliation(s)
- Sonja Sucic
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Ameya Kasture
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - H M Mazhar Asjad
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Carina Kern
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Ali El-Kasaby
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
| | - Michael Freissmuth
- Institute of Pharmacology, Center of Physiology and Pharmacology, Medical University of Vienna, A-1090 Vienna, Austria
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Pomozi V, Brampton C, Szeri F, Dedinszki D, Kozák E, van de Wetering K, Hopkins H, Martin L, Váradi A, Le Saux O. Functional Rescue of ABCC6 Deficiency by 4-Phenylbutyrate Therapy Reduces Dystrophic Calcification in Abcc6 -/- Mice. J Invest Dermatol 2016; 137:595-602. [PMID: 27826008 DOI: 10.1016/j.jid.2016.10.035] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2016] [Revised: 10/04/2016] [Accepted: 10/13/2016] [Indexed: 12/16/2022]
Abstract
Soft-tissue calcification is associated with aging, common conditions such as diabetes or hypercholesterolemia, and with certain genetic disorders. ABCC6 is an efflux transporter primarily expressed in liver facilitating the release of adenosine triphosphate from hepatocytes. Within the liver vasculature, adenosine triphosphate is converted into pyrophosphate, a major inhibitor of ectopic calcification. ABCC6 mutations thus lead to reduced plasma pyrophosphate levels, resulting in the calcification disorder pseudoxanthoma elasticum and some cases of generalized arterial calcification of infancy. Most mutations in ABCC6 are missense, and many preserve transport activity but are retained intracellularly. We have previously shown that the chemical chaperone 4-phenylbutyrate (4-PBA) promotes the maturation of ABCC6 mutants to the plasma membrane. In a humanized mouse model of pseudoxanthoma elasticum, we investigated whether 4-PBA treatments could rescue the calcification inhibition potential of selected ABCC6 mutants. We used the dystrophic cardiac calcification phenotype of Abcc6-/- mice as an indicator of ABCC6 function to quantify the effect of 4-PBA on human ABCC6 mutants transiently expressed in the liver. We showed that 4-PBA administrations restored the physiological function of ABCC6 mutants, resulting in enhanced calcification inhibition. This study identifies 4-PBA treatment as a promising strategy for allele-specific therapy of ABCC6-associated calcification disorders.
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Affiliation(s)
- Viola Pomozi
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA; Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Christopher Brampton
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Flóra Szeri
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Dóra Dedinszki
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Eszter Kozák
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Koen van de Wetering
- Division of Molecular Oncology, Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Hi'ilani Hopkins
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA
| | - Ludovic Martin
- University of Angers, Angers, France; CHU Angers, Centre de consultation PXE, Angers, France
| | - András Váradi
- Institute of Enzymology, RCNS, Hungarian Academy of Sciences, Budapest, Hungary
| | - Olivier Le Saux
- Department of Cell and Molecular Biology, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii, USA.
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Schmidt BZ, Haaf JB, Leal T, Noel S. Cystic fibrosis transmembrane conductance regulator modulators in cystic fibrosis: current perspectives. Clin Pharmacol 2016; 8:127-140. [PMID: 27703398 PMCID: PMC5036583 DOI: 10.2147/cpaa.s100759] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Mutations of the CFTR gene cause cystic fibrosis (CF), the most common recessive monogenic disease worldwide. These mutations alter the synthesis, processing, function, or half-life of CFTR, the main chloride channel expressed in the apical membrane of epithelial cells in the airway, intestine, pancreas, and reproductive tract. Lung disease is the most critical manifestation of CF. It is characterized by airway obstruction, infection, and inflammation that lead to fatal tissue destruction. In spite of great advances in early and multidisciplinary medical care, and in our understanding of the pathophysiology, CF is still considerably reducing the life expectancy of patients. This review highlights the current development in pharmacological modulators of CFTR, which aim at rescuing the expression and/or function of mutated CFTR. While only Kalydeco® and Orkambi® are currently available to patients, many other families of CFTR modulators are undergoing preclinical and clinical investigations. Drug repositioning and personalized medicine are particularly detailed in this review as they represent the most promising strategies for restoring CFTR function in CF.
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Affiliation(s)
- Béla Z Schmidt
- Stem Cell Biology and Embryology, Department of Development and Regeneration, Katholieke Universiteit Leuven, Leuven
| | - Jérémy B Haaf
- Louvain Center for Toxicology and Applied Pharmacology, Université Catholique de Louvain, Brussels, Belgium
| | - Teresinha Leal
- Louvain Center for Toxicology and Applied Pharmacology, Université Catholique de Louvain, Brussels, Belgium
| | - Sabrina Noel
- Louvain Center for Toxicology and Applied Pharmacology, Université Catholique de Louvain, Brussels, Belgium
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Altered Trafficking and Processing of GALC Mutants Correlates with Globoid Cell Leukodystrophy Severity. J Neurosci 2016; 36:1858-70. [PMID: 26865610 DOI: 10.1523/jneurosci.3095-15.2016] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Globoid cell leukodystrophy (GLD, Krabbe disease) is due to autosomal recessive mutations in the lysosomal enzyme galactosylceramidase (GALC). Many GLD patients develop infantile-onset of progressive neurologic deterioration and death by 2 years of age, whereas others have a later-onset, milder disease. Cord blood transplant slows disease progression much more effectively when performed presymptomatically, highlighting the importance of early diagnosis. Current diagnosis is based on reduced GALC activity, DNA sequence, and clinical examination. However, presymptomatic diagnosis is hampered by imperfect genotype-GALC activity-phenotype correlations. In addition, three polymorphisms in the GALC gene are variably associated with disease mutations and have unknown effects on GALC activity and disease outcome. Here, we study mutations that cause infantile or later-onset GLD, and show that GALC activity is significantly lower in infantile versus later-onset mutants when measured in the lysosomal fraction, but not in whole-cell lysates. In parallel, infantile-onset mutant GALCs showed reduced trafficking to lysosomes and processing than later-onset mutant GALCs. Finally, the cis-polymorphisms also affected trafficking to the lysosome and processing of GALC. These differences potentially explain why the activity of different mutations appears similar in whole-cell extracts from lymphocytes, and suggest that measure of GALC activity in lysosomes may better predict the onset and severity of disease for a given GLD genotype. SIGNIFICANCE STATEMENT Globoid cell leukodystrophy (GLD, Krabbe disease) is diagnosed by measuring galactosylceramidase (GALC) activity and DNA analysis. However, genotype and phenotype often do not correlate due to considerable clinical variability, even for the same mutation, for unknown reasons. We find that altered trafficking to the lysosome and processing of GALC correlates with GLD severity and is modulated by cis-polymorphisms. Current diagnosis of GLD is based on GALC activity of total cell lysates from blood, which does not discriminate whether the activity comes from the lysosome or other subcellular organelles. Measurement of GALC activity in lysosomes may predict which infants are at high risk for the infantile phenotype while distinguishing other children who will develop later-onset phenotypes without onset of symptoms for years.
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Kapur A, Felder M, Fass L, Kaur J, Czarnecki A, Rathi K, Zeng S, Osowski KK, Howell C, Xiong MP, Whelan RJ, Patankar MS. Modulation of oxidative stress and subsequent induction of apoptosis and endoplasmic reticulum stress allows citral to decrease cancer cell proliferation. Sci Rep 2016; 6:27530. [PMID: 27270209 PMCID: PMC4897611 DOI: 10.1038/srep27530] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 05/13/2016] [Indexed: 12/17/2022] Open
Abstract
The monoterpenoid, citral, when delivered through PEG-b-PCL nanoparticles inhibits in vivo growth of 4T1 breast tumors. Here, we show that citral inhibits proliferation of multiple human cancer cell lines. In p53 expressing ECC-1 and OVCAR-3 but not in p53-deficient SKOV-3 cells, citral induces G1/S cell cycle arrest and apoptosis as determined by Annexin V staining and increased cleaved caspase3 and Bax and decreased Bcl-2. In SKOV-3 cells, citral induces the ER stress markers CHOP, GADD45, EDEM, ATF4, Hsp90, ATG5, and phospho-eIF2α. The molecular chaperone 4-phenylbutyric acid attenuates citral activity in SKOV-3 but not in ECC-1 and OVCAR-3 cells. In p53-expressing cells, citral increases phosphorylation of serine-15 of p53. Activation of p53 increases Bax, PUMA, and NOXA expression. Inhibition of p53 by pifithrin-α, attenuates citral-mediated apoptosis. Citral increases intracellular oxygen radicals and this leads to activation of p53. Inhibition of glutathione synthesis by L-buthionine sulfoxamine increases potency of citral. Pretreatment with N-acetylcysteine decreases phosphorylation of p53 in citral-treated ECC-1 and OVCAR-3. These results define a p53-dependent, and in the absence of p53, ER stress-dependent mode of action of citral. This study indicates that citral in PEG-b-PCL nanoparticle formulation should be considered for treatment of breast and other tumors.
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Affiliation(s)
- Arvinder Kapur
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI-53792-6188, USA
| | - Mildred Felder
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI-53792-6188, USA
| | - Lucas Fass
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI-53792-6188, USA
| | - Justanjot Kaur
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI-53792-6188, USA
| | - Austin Czarnecki
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI-53792-6188, USA
| | - Kavya Rathi
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI-53792-6188, USA
| | - San Zeng
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705-2222, USA
| | | | - Colin Howell
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, OH 44704, USA
| | - May P Xiong
- School of Pharmacy, University of Wisconsin-Madison, Madison, Wisconsin 53705-2222, USA
| | - Rebecca J Whelan
- Department of Chemistry and Biochemistry, Oberlin College, Oberlin, OH 44704, USA
| | - Manish S Patankar
- Department of Obstetrics and Gynecology, University of Wisconsin-Madison, Madison, WI-53792-6188, USA
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In Vivo and In Vitro Evidence for Brain Uptake of 4-Phenylbutyrate by the Monocarboxylate Transporter 1 (MCT1). Pharm Res 2016; 33:1711-22. [PMID: 27026010 DOI: 10.1007/s11095-016-1912-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 03/22/2016] [Indexed: 10/22/2022]
Abstract
PURPOSE 4-Phenylbutyrate (4-PBA) is expected to be a potential therapeutic for several neurodegenerative diseases. These activities require 4-PBA transport into the brain across the blood-brain barrier (BBB). The objective of the present study was to characterize the brain transport mechanism of 4-PBA through the BBB. METHODS The brain transport of 4-PBA across the BBB was investigated following intravenous (IV) injection and internal carotid artery perfusion (ICAP) in vivo. The mechanism of transport was examined using TR-BBB cells, an in vitro model of the BBB. RESULTS The volume of distribution (VD) of 4-PBA by rat brain was about 7-fold greater than that of sucrose, a BBB impermeable vascular space marker, suggesting the blood-to-brain transport of 4-PBA through the BBB in the physiological state. [(14)C]4-PBA uptake by TR-BBB cells showed time-, pH- and concentration-dependence with a K m of 13.4 mM at pH 7.4 and 3.22 mM at pH 6.0. The uptake was Na(+) independent, and was significantly inhibited by alpha-cyano-4-hydroxycinnamate (a typical inhibitor for monocarboxylate transport), endogenous monocarboxylate compounds and monocarboxylic drugs. Lactate and valproate competitively inhibited [(14)C]4-PBA uptake with K i value of 13.5 mM and 7.47 mM, respectively. These results indicate the role of monocarboxylate transporters (MCTs) in 4-PBA transport into the brain at the BBB. TR-BBB cells expressed mRNA of rMCT1, 2, and 4, especially, rMCT1 showed high mRNA expression level. In addition, [(14)C]4-PBA uptake was inhibited by rMCT1 specific small interfering RNA. CONCLUSION The transport mechanism of 4-PBA from blood to brain across the BBB likely involves MCT1.
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Donegan RK, Lieberman RL. Discovery of Molecular Therapeutics for Glaucoma: Challenges, Successes, and Promising Directions. J Med Chem 2016; 59:788-809. [PMID: 26356532 PMCID: PMC5547565 DOI: 10.1021/acs.jmedchem.5b00828] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Glaucoma, a heterogeneous ocular disorder affecting ∼60 million people worldwide, is characterized by painless neurodegeneration of retinal ganglion cells (RGCs), resulting in irreversible vision loss. Available therapies, which decrease the common causal risk factor of elevated intraocular pressure, delay, but cannot prevent, RGC death and blindness. Notably, it is changes in the anterior segment of the eye, particularly in the drainage of aqueous humor fluid, which are believed to bring about changes in pressure. Thus, it is primarily this region whose properties are manipulated in current and emerging therapies for glaucoma. Here, we focus on the challenges associated with developing treatments, review the available experimental methods to evaluate the therapeutic potential of new drugs, describe the development and evaluation of emerging Rho-kinase inhibitors and adenosine receptor ligands that offer the potential to improve aqueous humor outflow and protect RGCs simultaneously, and present new targets and approaches on the horizon.
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Affiliation(s)
- Rebecca K Donegan
- School of Chemistry and Biochemistry, Georgia Institute of Technology , 901 Atlantic Drive NW, Atlanta, Georgia 30332-0400, United States
| | - Raquel L Lieberman
- School of Chemistry and Biochemistry, Georgia Institute of Technology , 901 Atlantic Drive NW, Atlanta, Georgia 30332-0400, United States
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45
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Yue ZS, Zeng LR, Quan RF, Tang YH, Zheng WJ, Qu G, Xu CD, Zhu FB, Huang ZM. 4‑Phenylbutyrate protects rat skin flaps against ischemia‑reperfusion injury and apoptosis by inhibiting endoplasmic reticulum stress. Mol Med Rep 2015; 13:1227-33. [PMID: 26648447 PMCID: PMC4732847 DOI: 10.3892/mmr.2015.4636] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2015] [Accepted: 11/18/2015] [Indexed: 01/07/2023] Open
Abstract
4-phenylbutyrate (4-PBA) is a low molecular weight fatty acid, which has been demonstrated to regulate endoplasmic reticulum (ER) stress. ER stress-induced cell apoptosis has an important role in skin flap ischemia; however, a pharmacological approach for treating ischemia-induced ER dysfunction has yet to be reported. In the present study, the effects of 4-PBA-induced ER stress inhibition on ischemia-reperfusion injury were investigated in the skin flap of rats, and transcriptional regulation was examined. 4-PBA attenuated ischemia-reperfusion injury and inhibited cell apoptosis in the skin flap. Furthermore, 4-PBA reversed the increased expression levels of two ER stress markers: CCAAT/enhancer-binding protein-homologous protein and glucose-regulated protein 78. These results suggested that 4-PBA was able to protect rat skin flaps against ischemia-reperfusion injury and apoptosis by inhibiting ER stress marker expression and ER stress-mediated apoptosis. The beneficial effects of 4-PBA may prove useful in the treatment of skin flap ischemia-reperfusion injury.
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Affiliation(s)
- Zhen-Shuang Yue
- Department of Orthopedics, Xiaoshan Traditional Chinese Medical Hospital, Hangzhou, Zhejiang 311201, P.R. China
| | - Lin-Ru Zeng
- Department of Orthopedics, Xiaoshan Traditional Chinese Medical Hospital, Hangzhou, Zhejiang 311201, P.R. China
| | - Ren-Fu Quan
- Department of Orthopedics, Xiaoshan Traditional Chinese Medical Hospital, Hangzhou, Zhejiang 311201, P.R. China
| | - Yang-Hua Tang
- Department of Orthopedics, Xiaoshan Traditional Chinese Medical Hospital, Hangzhou, Zhejiang 311201, P.R. China
| | - Wen-Jie Zheng
- Department of Orthopedics, Xiaoshan Traditional Chinese Medical Hospital, Hangzhou, Zhejiang 311201, P.R. China
| | - Gang Qu
- Department of Orthopedics, Xiaoshan Traditional Chinese Medical Hospital, Hangzhou, Zhejiang 311201, P.R. China
| | - Can-Da Xu
- Department of Orthopedics, Xiaoshan Traditional Chinese Medical Hospital, Hangzhou, Zhejiang 311201, P.R. China
| | - Fang-Bing Zhu
- Department of Orthopedics, Xiaoshan Traditional Chinese Medical Hospital, Hangzhou, Zhejiang 311201, P.R. China
| | - Zhong-Ming Huang
- Department of Orthopedics, Xiaoshan Traditional Chinese Medical Hospital, Hangzhou, Zhejiang 311201, P.R. China
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Zaman K, Sawczak V, Zaidi A, Butler M, Bennett D, Getsy P, Zeinomar M, Greenberg Z, Forbes M, Rehman S, Jyothikumar V, DeRonde K, Sattar A, Smith L, Corey D, Straub A, Sun F, Palmer L, Periasamy A, Randell S, Kelley TJ, Lewis SJ, Gaston B. Augmentation of CFTR maturation by S-nitrosoglutathione reductase. Am J Physiol Lung Cell Mol Physiol 2015; 310:L263-70. [PMID: 26637637 DOI: 10.1152/ajplung.00269.2014] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 11/20/2015] [Indexed: 12/27/2022] Open
Abstract
S-nitrosoglutathione (GSNO) reductase regulates novel endogenous S-nitrosothiol signaling pathways, and mice deficient in GSNO reductase are protected from airways hyperreactivity. S-nitrosothiols are present in the airway, and patients with cystic fibrosis (CF) tend to have low S-nitrosothiol levels that may be attributed to upregulation of GSNO reductase activity. The present study demonstrates that 1) GSNO reductase activity is increased in the cystic fibrosis bronchial epithelial (CFBE41o(-)) cells expressing mutant F508del-cystic fibrosis transmembrane regulator (CFTR) compared with the wild-type CFBE41o(-) cells, 2) GSNO reductase expression level is increased in the primary human bronchial epithelial cells expressing mutant F508del-CFTR compared with the wild-type cells, 3) GSNO reductase colocalizes with cochaperone Hsp70/Hsp90 organizing protein (Hop; Stip1) in human airway epithelial cells, 4) GSNO reductase knockdown with siRNA increases the expression and maturation of CFTR and decreases Stip1 expression in human airway epithelial cells, 5) increased levels of GSNO reductase cause a decrease in maturation of CFTR, and 6) a GSNO reductase inhibitor effectively reverses the effects of GSNO reductase on CFTR maturation. These studies provide a novel approach to define the subcellular location of the interactions between Stip1 and GSNO reductase and the role of S-nitrosothiols in these interactions.
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Affiliation(s)
- Khalequz Zaman
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Victoria Sawczak
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Atiya Zaidi
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Maya Butler
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Deric Bennett
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Paulina Getsy
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Maryam Zeinomar
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Zivi Greenberg
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Michael Forbes
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Shagufta Rehman
- W. M. Keck Center for Cellular Imaging, Department of Biology, University of Virginia, Charlottesville, Virginiga
| | - Vinod Jyothikumar
- W. M. Keck Center for Cellular Imaging, Department of Biology, University of Virginia, Charlottesville, Virginiga
| | - Kim DeRonde
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Abdus Sattar
- Department of Epidemiology and Biostatistics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Laura Smith
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Deborah Corey
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Adam Straub
- Cardiovascular Research Center, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Fei Sun
- Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan
| | - Lisa Palmer
- Pediatric Respiratory Medicine, Department of Pediatrics, University of Virginia School of Medicine, Charlottesville, Virginia
| | - Ammasi Periasamy
- W. M. Keck Center for Cellular Imaging, Department of Biology, University of Virginia, Charlottesville, Virginiga
| | - Scott Randell
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Thomas J Kelley
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Stephen J Lewis
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio
| | - Benjamin Gaston
- Pediatric Pulmonology Division, Department of Pediatrics, Case Western Reserve University School of Medicine, Cleveland, Ohio; Pediatric Pulmonology Division, Rainbow Babies and Children's Hospital, Cleveland, Ohio
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Braun D, Schweizer U. Efficient Activation of Pathogenic ΔPhe501 Mutation in Monocarboxylate Transporter 8 by Chemical and Pharmacological Chaperones. Endocrinology 2015; 156:4720-30. [PMID: 26368820 DOI: 10.1210/en.2015-1393] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Monocarboxylate transporter 8 (MCT8) is a thyroid hormone transmembrane transporter expressed in many cell types, including neurons. Mutations that inactivate transport activity of MCT8 cause severe X-linked psychomotor retardation in male patients, a syndrome originally described as the Allan-Herndon-Dudley syndrome. Treatment options currently explored the focus on finding thyroid hormone-like compounds that bypass MCT8 and enter cells through different transporters. Because MCT8 is a multipass transmembrane protein, some pathogenic mutations affect membrane trafficking while potentially retaining some transporter activity. We explore here the effects of chemical and pharmacological chaperones on the expression and transport activity of the MCT8 mutant ΔPhe501. Dimethylsulfoxide, 4-phenylbutyric acid as well as its sodium salt, and the isoflavone genistein increase T3 uptake into MDCK1 cells stably transfected with mutant MCT8-ΔPhe501. We show that ΔPhe501 represents a temperature-sensitive mutant protein that is stabilized by the proteasome inhibitor MG132. 4-Phenylbutyrate has been used to stabilize ΔPhe508 mutant cystic fibrosis transmembrane conductance regulator protein and is in clinical use in patients with urea cycle defects. Genistein is enriched in soy and available as a nutritional supplement. It is effective in stabilizing MCT8-ΔPhe501 at 100 nM concentration. Expression of the L471P mutant is increased in response to phenylbutyrate, but T3 uptake activity is not induced, supporting the notion that the chaperone specifically increases membrane expression. Our findings suggest that certain pathogenic MCT8 mutants may be responsive to (co-)treatment with readily available compounds, which increase endogenous protein function.
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Affiliation(s)
- Doreen Braun
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität, 53115 Bonn, Germany
| | - Ulrich Schweizer
- Institut für Biochemie und Molekularbiologie, Rheinische Friedrich-Wilhelms-Universität, 53115 Bonn, Germany
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Luo T, Chen B, Wang X. 4-PBA prevents pressure overload-induced myocardial hypertrophy and interstitial fibrosis by attenuating endoplasmic reticulum stress. Chem Biol Interact 2015; 242:99-106. [PMID: 26428355 DOI: 10.1016/j.cbi.2015.09.025] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2015] [Revised: 09/01/2015] [Accepted: 09/24/2015] [Indexed: 01/14/2023]
Abstract
Our previous study indicated that attenuation of endoplasmic reticulum (ER) stress by administration of 4-phenylbutyric acid (4-PBA) could prevent cardiac rupture and remodeling in a mouse model of myocardial infarction (MI). However, whether 4-PBA is protective in hypertrophic heart disease is unclear. Thus, we tested the therapeutic effect of 4-PBA on pressure-overload induced myocardial hypertrophy. Transverse aortic constriction (TAC) was used to create myocardial hypertrophy in C57BL/6 male mice for 4 weeks. Immediately after surgery, the mice were administrated either 4-PBA (20 mg/kg/day) or 0.9% NaCl by intraperitoneal injection. At the end of 4 weeks, the mice underwent high-resolution echocardiographic imaging. Our results showed that both the left ventricular posterior wall thickness at end systole (LVPWs) and diastole (LVPWd) were increased in the TAC group, compared to control. 4-PBA administration attenuated hypertrophy and decreased the heart weight over body weight ratio. Masson's trichrome staining showed that myocardial interstitial fibrosis and collagen deposition were also decreased by 4-PBA. We next detected the ER stress response in the heart tissues of TAC mice in different time points. Western blotting showed that the expression of ER stress marker, GRP78, CHOP and phosphor-PERK, were persistently increased 4 weeks after TAC. The treatment of 4-PBA inhibited the expression of ER stress markers. We also demonstrated that the 4-PBA at 20 mg/kg/day had no effect on histone 3 deacetylation inhibition, while attenuating ER stress and TAC-induced hypertrophy. These findings suggest that 4-PBA may be a therapeutic strategy to consider in preventing pressure-overload induced myocardial hypertrophy and interstitial fibrosis by selectively attenuating ER stress.
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Affiliation(s)
- Tao Luo
- Division of Cardiology, Department of Medicine, University of California Irvine Medical Center, Orange, CA 92868, USA.
| | - Baihe Chen
- Department of Molecular Biology & Biochemistry, University of California Irvine, Irvine, CA 92697, USA
| | - Xianbao Wang
- Department of Cardiology, Zhujiang Hospital of Southern Medical University, Guangzhou, 510282, PR China
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49
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Thompson RJ, Bull LN. Treating genetic disease: Expanding the options. Hepatology 2015; 62:349-51. [PMID: 25820708 DOI: 10.1002/hep.27817] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 03/27/2015] [Indexed: 12/13/2022]
Affiliation(s)
- Richard J Thompson
- Institute of Liver Studies Division of Transplantation Immunology and Mucosal Biology, King's College London, London, UK.,Pediatric Liver, GI and Nutrition Center, King's College Hospital, London, UK
| | - Laura N Bull
- Liver Center Laboratory Department of Medicine, University of California San Francisco, San Francisco, CA.,Institute for Human Genetics, University of California San Francisco, San Francisco, CA
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Norez C, Vandebrouck C, Bertrand J, Noel S, Durieu E, Oumata N, Galons H, Antigny F, Chatelier A, Bois P, Meijer L, Becq F. Roscovitine is a proteostasis regulator that corrects the trafficking defect of F508del-CFTR by a CDK-independent mechanism. Br J Pharmacol 2015; 171:4831-49. [PMID: 25065395 DOI: 10.1111/bph.12859] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2013] [Revised: 03/07/2014] [Accepted: 04/10/2014] [Indexed: 12/25/2022] Open
Abstract
BACKGROUND AND PURPOSE The most common mutation in cystic fibrosis (CF), F508del, causes defects in trafficking, channel gating and endocytosis of the CF transmembrane conductance regulator (CFTR) protein. Because CF is an orphan disease, therapeutic strategies aimed at improving mutant CFTR functions are needed to target the root cause of CF. EXPERIMENTAL APPROACH Human CF airway epithelial cells were treated with roscovitine 100 μM for 2 h before CFTR maturation, expression and activity were examined. The mechanism of action of roscovitine was explored by recording the effect of depleting endoplasmic reticulum (ER) Ca(2+) on the F508del-CFTR/calnexin interaction and by measuring proteasome activity. KEY RESULTS Of the cyclin-dependent kinase (CDK) inhibitors investigated, roscovitine was found to restore the cell surface expression and defective channel function of F508del-CFTR in human CF airway epithelial cells. Neither olomoucine nor (S)-CR8, two very efficient CDK inhibitors, corrected F508del-CFTR trafficking demonstrating that the correcting effect of roscovitine was independent of CDK inhibition. Competition studies with inhibitors of the ER quality control (ERQC) indicated that roscovitine acts on the calnexin pathway and on the degradation machinery. Roscovitine was shown (i) to partially inhibit the interaction between F508del-CFTR and calnexin by depleting ER Ca(2+) and (ii) to directly inhibit the proteasome activity in a Ca(2+) -independent manner. CONCLUSIONS AND IMPLICATIONS Roscovitine is able to correct the defective function of F508del-CFTR by preventing the ability of the ERQC to interact with and degrade F508del-CFTR via two synergistic but CDK-independent mechanisms. Roscovitine has potential as a pharmacological therapy for CF.
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Affiliation(s)
- C Norez
- Institut de Physiologie et Biologie Cellulaires, Université de Poitiers, Poitiers, France
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