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Joshi SM, Wilson TC, Li Z, Preshlock S, Gómez-Vallejo V, Gouverneur V, Llop J, Arsequell G. Synthesis and PET Imaging Biodistribution Studies of Radiolabeled Iododiflunisal, a Transthyretin Tetramer Stabilizer, Candidate Drug for Alzheimer's Disease. Molecules 2024; 29:488. [PMID: 38257401 PMCID: PMC10818730 DOI: 10.3390/molecules29020488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2023] [Revised: 01/08/2024] [Accepted: 01/12/2024] [Indexed: 01/24/2024] Open
Abstract
The small-molecule iododiflunisal (IDIF) is a transthyretin (TTR) tetramer stabilizer and acts as a chaperone of the TTR-Amyloid beta interaction. Oral administration of IDIF improves Alzheimer's Disease (AD)-like pathology in mice, although the mechanism of action and pharmacokinetics remain unknown. Radiolabeling IDIF with positron or gamma emitters may aid in the in vivo evaluation of IDIF using non-invasive nuclear imaging techniques. In this work, we report an isotopic exchange reaction to obtain IDIF radiolabeled with 18F. [19F/18F]exchange reaction over IDIF in dimethyl sulfoxide at 160 °C resulted in the formation of [18F]IDIF in 7 ± 3% radiochemical yield in a 20 min reaction time, with a final radiochemical purity of >99%. Biodistribution studies after intravenous administration of [18F]IDIF in wild-type mice using positron emission tomography (PET) imaging showed capacity to cross the blood-brain barrier (ca. 1% of injected dose per gram of tissue in the brain at t > 10 min post administration), rapid accumulation in the liver, long circulation time, and progressive elimination via urine. Our results open opportunities for future studies in larger animal species or human subjects.
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Affiliation(s)
- Sameer M. Joshi
- CIC BiomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo Miramón 182, Parque Tecnológico de San Sebastián, 20009 Donostia-San Sebastián, Spain; (S.M.J.); (V.G.-V.)
- Department of Radiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
| | - Thomas C. Wilson
- Chemistry Research Laboratory, Oxford University, Oxford OX1 3TA, UK; (T.C.W.); (V.G.)
| | - Zibo Li
- Department of Radiology, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA;
- Lineberger Comprehensive Cancer Center, The University of North Carolina at Chapel Hill, Chapel Hill, NC 27514, USA
| | - Sean Preshlock
- Chemistry Research Laboratory, Oxford University, Oxford OX1 3TA, UK; (T.C.W.); (V.G.)
| | - Vanessa Gómez-Vallejo
- CIC BiomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo Miramón 182, Parque Tecnológico de San Sebastián, 20009 Donostia-San Sebastián, Spain; (S.M.J.); (V.G.-V.)
| | - Véronique Gouverneur
- Chemistry Research Laboratory, Oxford University, Oxford OX1 3TA, UK; (T.C.W.); (V.G.)
| | - Jordi Llop
- CIC BiomaGUNE, Basque Research and Technology Alliance (BRTA), Paseo Miramón 182, Parque Tecnológico de San Sebastián, 20009 Donostia-San Sebastián, Spain; (S.M.J.); (V.G.-V.)
| | - Gemma Arsequell
- Institut de Química Avançada de Catalunya (IQAC), Spanish National Research Council (CSIC), 08034 Barcelona, Spain
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Agarwal N, Sharma S, Sultan J. Chemistry, Biological Properties, and Bio-analysis of Tafamidis, a New Transthyretin Stabilizer: A Systematic Review. Cardiovasc Hematol Agents Med Chem 2024; 22:121-130. [PMID: 38031770 DOI: 10.2174/0118715257250153231011062855] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Revised: 07/25/2023] [Accepted: 08/15/2023] [Indexed: 12/01/2023]
Abstract
BACKGROUND Cardiomyopathy is a global health crisis that affects people all over the world. Consequently, scientists felt compelled to look for and develop ever-more-powerful pharmaceuticals. For ATTR-CM, the only drug currently recommended by the European Society of Cardiology is Tafamidis. OBJECTIVES The primary aim of this review article is to understand the chemistry, pharmacodynamic, pharmacokinetic, and bio-analytical methods available for Tafamidis. METHODS A systematic review of the existing resources was accomplished up to 2022, comprising existing studies forming the database covering the existing resources from Web of Science, ScienceDirect, and PubMed. RESULTS The review was based on a systematic review of all the existing studies used to formulate the database. The study also illustrated the PRISMA design that systematically analyses the prevalent resources. CONCLUSION Minimal analytical techniques are observed for quantifying the Tafamidis and transthyretin kinetic stabiliser. Therapeutic, pharmacological, and analytical considerations for the novel drug Tafamidis are discussed in this review. Particular attention is paid to the many different analytical and bioanalytical methods currently available for estimating Tafamidis, and the need is highlighted to develop a straightforward, validated technique that meets green chemistry standards.
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Affiliation(s)
- Nikhil Agarwal
- Department of Quality Assurance, Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management, SVKM's NMIMS Deemed to be University, Vile Parle West, Mumbai, Maharashtra, 400056, India
| | - Sanjay Sharma
- Department of Quality Assurance, Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management, SVKM's NMIMS Deemed to be University, Vile Parle West, Mumbai, Maharashtra, 400056, India
| | - Jasira Sultan
- Department of Quality Assurance, Shobhaben Pratapbhai Patel School of Pharmacy & Technology Management, SVKM's NMIMS Deemed to be University, Vile Parle West, Mumbai, Maharashtra, 400056, India
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3
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Ciccone L, Tonali N, Nencetti S, Orlandini E. Natural compounds as inhibitors of transthyretin amyloidosis and neuroprotective agents: analysis of structural data for future drug design. J Enzyme Inhib Med Chem 2020; 35:1145-1162. [PMID: 32419519 PMCID: PMC7301710 DOI: 10.1080/14756366.2020.1760262] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Revised: 04/17/2020] [Accepted: 04/20/2020] [Indexed: 12/13/2022] Open
Abstract
Natural compounds, such as plant and fruit extracts have shown neuroprotective effect against neurodegenerative diseases. It has been reported that several natural compounds binding to transthyretin (TTR) can be useful in amyloidosis prevention. TTR is a transporter protein that under physiological condition carries thyroxine (T4) and retinol in plasma and in cerebrospinal fluid (CSF); it also has a neuroprotective role against Alzheimer's disease (AD). However, TTR also is an amyloidogenic protein responsible for familial amyloid polyneuropathy (FAP) and familial amyloid cardiomyopathy (FAC). The TTR amyloidogenic potential is speeded up by several point mutations. One therapeutic strategy against TTR amyloidosis is the stabilisation of the native tetramer by natural compounds and small molecules. In this review, we examine the natural products that, starting from 2012 to present, have been studied as a stabiliser of TTR tetramer. In particular, we discussed the chemical and structural features which will be helpful for future drug design of new TTR stabilisers.
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Affiliation(s)
- Lidia Ciccone
- Department of Pharmacy, University of Pisa, Pisa, Italy
| | - Nicoló Tonali
- CNRS, Université Paris-Saclay, Châtenay-Malabry, France
| | - Susanna Nencetti
- Department of Pharmacy, University of Pisa, Pisa, Italy
- Interdepartmental Research Centre “Nutraceuticals and Food for Health (NUTRAFOOD), University of Pisa, Pisa, Italy
| | - Elisabetta Orlandini
- Department of Earth Sciences, University of Pisa, Pisa, Italy
- Research Center “E. Piaggio”, University of Pisa, Pisa, Italy
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4
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Cioffi CL, Muthuraman P, Raja A, Varadi A, Racz B, Petrukhin K. Discovery of Bispecific Antagonists of Retinol Binding Protein 4 That Stabilize Transthyretin Tetramers: Scaffolding Hopping, Optimization, and Preclinical Pharmacological Evaluation as a Potential Therapy for Two Common Age-Related Comorbidities. J Med Chem 2020; 63:11054-11084. [DOI: 10.1021/acs.jmedchem.0c00996] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Christopher L. Cioffi
- Departments of Basic and Clinical Sciences and Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, 106 New Scotland Avenue, Albany, New York 12208, United States
| | - Parthasarathy Muthuraman
- Departments of Basic and Clinical Sciences and Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, 106 New Scotland Avenue, Albany, New York 12208, United States
| | - Arun Raja
- Departments of Basic and Clinical Sciences and Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences, 106 New Scotland Avenue, Albany, New York 12208, United States
| | - Andras Varadi
- Department of Ophthalmology, Columbia University Medical Center, New York, New York 10032, United States
| | - Boglarka Racz
- Department of Ophthalmology, Columbia University Medical Center, New York, New York 10032, United States
| | - Konstantin Petrukhin
- Department of Ophthalmology, Columbia University Medical Center, New York, New York 10032, United States
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5
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Cotrina EY, Gimeno A, Llop J, Jiménez-Barbero J, Quintana J, Valencia G, Cardoso I, Prohens R, Arsequell G. Calorimetric Studies of Binary and Ternary Molecular Interactions between Transthyretin, Aβ Peptides, and Small-Molecule Chaperones toward an Alternative Strategy for Alzheimer's Disease Drug Discovery. J Med Chem 2020; 63:3205-3214. [PMID: 32124607 PMCID: PMC7115756 DOI: 10.1021/acs.jmedchem.9b01970] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
![]()
Transthyretin
(TTR) modulates the deposition, processing, and toxicity
of Abeta (Aβ) peptides. We have shown that this effect is enhanced
in mice by treatment with small molecules such as iododiflunisal (IDIF, 4), a good TTR stabilizer. Here, we describe the thermodynamics
of the formation of binary and ternary complexes among TTR, Aβ(1–42)
peptide, and TTR stabilizers using isothermal titration calorimetry
(ITC). A TTR/Aβ(1–42) (1:1)
complex with a dissociation constant of Kd = 0.94 μM is formed; with IDIF
(4), this constant improves up to Kd = 0.32 μM, indicating
the presence of a ternary complex TTR/IDIF/Aβ(1–42).
However, with the drugs diflunisal (1) or Tafamidis (2), an analogous chaperoning effect could not be observed.
Similar phenomena could be recorded with the shorter peptide Aβ(12–28)
(7). We propose the design of a simple assay system for
the search of other chaperones that behave like IDIF and may become
potential candidate drugs for Alzheimer’s disease (AD).
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Affiliation(s)
- Ellen Y Cotrina
- Institut de Quı́mica Avançada de Catalunya (I.Q.A.C.-C.S.I.C.), 08034 Barcelona, Spain
| | - Ana Gimeno
- CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 800, 48160 Derio, Spain
| | - Jordi Llop
- CIC biomaGUNE, Basque Research and Technology Alliance (BRTA), 20014 San Sebastian, Spain
| | - Jesús Jiménez-Barbero
- CIC bioGUNE, Basque Research and Technology Alliance (BRTA), Bizkaia Technology Park, Building 800, 48160 Derio, Spain.,Ikerbasque, Basque Foundation for Science, Maria Diaz de Haro 13, 48009 Bilbao, Spain.,Department of Organic Chemistry II, Faculty of Science & Technology, University of the Basque Country, 48940 Leioa, Bizkaia, Spain
| | - Jordi Quintana
- Research Programme on Biomedical Informatics, Universitat Pompeu Fabra (UPF-IMIM), 08003 Barcelona, Spain
| | - Gregorio Valencia
- Institut de Quı́mica Avançada de Catalunya (I.Q.A.C.-C.S.I.C.), 08034 Barcelona, Spain
| | - Isabel Cardoso
- IBMC-Instituto de Biologia Molecular e Celular, 4200-135 Porto, Portugal.,i3S-Instituto de Investigação e Inovação em Saúde, Universidade do Porto, 4200-135 Porto, Portugal
| | - Rafel Prohens
- Unitat de Polimorfisme i Calorimetria, Centres Cientı́fics i Tecnològics, Universitat de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain
| | - Gemma Arsequell
- Institut de Quı́mica Avançada de Catalunya (I.Q.A.C.-C.S.I.C.), 08034 Barcelona, Spain
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Rios X, Gómez-Vallejo V, Martín A, Cossío U, Morcillo MÁ, Alemi M, Cardoso I, Quintana J, Jiménez-Barbero J, Cotrina EY, Valencia G, Arsequell G, Llop J. Radiochemical examination of transthyretin (TTR) brain penetration assisted by iododiflunisal, a TTR tetramer stabilizer and a new candidate drug for AD. Sci Rep 2019; 9:13672. [PMID: 31541162 PMCID: PMC6754432 DOI: 10.1038/s41598-019-50071-w] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2018] [Accepted: 08/31/2019] [Indexed: 12/21/2022] Open
Abstract
It is well settled that the amyloidogenic properties of the plasma protein transporter transthyretin (TTR) can be modulated by compounds that stabilize its native tetrameric conformation. TTR is also present in cerebrospinal fluid where it can bind to Aβ-peptides and prevent Aβ aggregation. We have previously shown that treatment of Alzheimer’s Disease (AD) model mice with iododiflunisal (IDIF), a TTR tetramer stabilizing compound, prevents AD pathologies. This evidence positioned IDIF as a new lead drug for AD. In dissecting the mechanism of action of IDIF, we disclose here different labeling strategies for the preparation of 131I-labeled IDIF and 131I- and 124I-labeled TTR, which have been further used for the preparation of IDIF-TTR complexes labeled either on the compound or the protein. The biodistribution of all labeled species after intravenous administration has been investigated in mice using ex vivo and in vivo techniques. Our results confirm the capacity of TTR to cross the blood brain barrier (BBB) and suggest that the formation of TTR-IDIF complexes enhances BBB permeability of both IDIF and TTR. The increased TTR and IDIF brain concentrations may result in higher Aβ-peptide sequestration capacity with the subsequent inhibition of AD symptoms as we have previously observed in mice.
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Affiliation(s)
- Xabier Rios
- Radiochemistry and Nuclear Imaging Group, CIC biomaGUNE, 20014, San Sebastián, Guipúzcoa, Spain
| | - Vanessa Gómez-Vallejo
- Radiochemistry and Nuclear Imaging Group, CIC biomaGUNE, 20014, San Sebastián, Guipúzcoa, Spain
| | - Abraham Martín
- Achucarro Basque Center for Neuroscience, 48940, Leioa, Spain.,Ikerbasque Basque Foundation for Science, Maria Díaz de Haro 3, 48013, Bilbao, Spain
| | - Unai Cossío
- Radiochemistry and Nuclear Imaging Group, CIC biomaGUNE, 20014, San Sebastián, Guipúzcoa, Spain
| | - Miguel Ángel Morcillo
- Biomedical Applications of Radioisotopes and Pharmacokinetics Unit, CIEMAT, 28040, Madrid, Spain
| | - Mobina Alemi
- IBMC - Instituto de Biologia Celular e Molecular, i3S-Instituto de Investigação e Inovação em Saúde, 4200-135, Porto, Portugal
| | - Isabel Cardoso
- IBMC - Instituto de Biologia Celular e Molecular, i3S-Instituto de Investigação e Inovação em Saúde, 4200-135, Porto, Portugal
| | - Jordi Quintana
- Plataforma Drug Discovery, Parc Científic de Barcelona (PCB), 08028, Barcelona, Spain.,Research Programme on Biomedical Informatics, Universitat Pompeu Fabra, 08003, Barcelona, Spain
| | - Jesús Jiménez-Barbero
- Ikerbasque Basque Foundation for Science, Maria Díaz de Haro 3, 48013, Bilbao, Spain.,CIC bioGUNE, Bizkaia Technology Park, Building 800, 48160, Derio, Spain
| | - Ellen Y Cotrina
- Institut de Química Avançada de Catalunya (I.Q.A.C.-C.S.I.C.), 08034, Barcelona, Spain
| | - Gregorio Valencia
- Institut de Química Avançada de Catalunya (I.Q.A.C.-C.S.I.C.), 08034, Barcelona, Spain
| | - Gemma Arsequell
- Institut de Química Avançada de Catalunya (I.Q.A.C.-C.S.I.C.), 08034, Barcelona, Spain.
| | - Jordi Llop
- Radiochemistry and Nuclear Imaging Group, CIC biomaGUNE, 20014, San Sebastián, Guipúzcoa, Spain. .,Centro de Investigación Biomédica en Red- Enfermedades Respiratorias (CIBERES), Madrid, Spain.
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7
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Biology and Pathobiology of TDP-43 and Emergent Therapeutic Strategies. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a024554. [PMID: 27920024 DOI: 10.1101/cshperspect.a024554] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Cytoplasmic TDP-43 mislocalization and aggregation is a pathological hallmark of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. TDP-43 is an RNA-binding protein (RBP) with a prion-like domain (PrLD) that promotes TDP-43 misfolding. PrLDs possess compositional similarity to canonical prion domains of various yeast proteins, including Sup35. Strikingly, disease-causing TDP-43 mutations reside almost exclusively in the PrLD and can enhance TDP-43 misfolding and toxicity. Another ∼70 human RBPs harbor PrLDs, including FUS, TAF15, EWSR1, hnRNPA1, and hnRNPA2, which have surfaced in the etiology of neurodegenerative diseases. Importantly, PrLDs enable RBP function and mediate phase transitions that partition functional ribonucleoprotein compartments. This PrLD activity, however, renders RBPs prone to populating deleterious oligomers or self-templating fibrils that might spread disease, and disease-linked PrLD mutations can exacerbate this risk. Several strategies have emerged to counter TDP-43 proteinopathies, including engineering enhanced protein disaggregases based on Hsp104.
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Iakovleva I, Begum A, Brännström K, Wijsekera A, Nilsson L, Zhang J, Andersson PL, Sauer-Eriksson AE, Olofsson A. Tetrabromobisphenol A Is an Efficient Stabilizer of the Transthyretin Tetramer. PLoS One 2016; 11:e0153529. [PMID: 27093678 PMCID: PMC4836675 DOI: 10.1371/journal.pone.0153529] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Accepted: 03/30/2016] [Indexed: 01/15/2023] Open
Abstract
Amyloid formation of the human plasma protein transthyretin (TTR) is associated with several human disorders, including familial amyloidotic polyneuropathy (FAP) and senile systemic amyloidosis. Dissociation of TTR's native tetrameric assembly is the rate-limiting step in the conversion into amyloid, and this feature presents an avenue for intervention because binding of an appropriate ligand to the thyroxin hormone binding sites of TTR stabilizes the native tetrameric assembly and impairs conversion into amyloid. The desired features for an effective TTR stabilizer include high affinity for TTR, high selectivity in the presence of other proteins, no adverse side effects at the effective concentrations, and a long half-life in the body. In this study we show that the commonly used flame retardant tetrabromobisphenol A (TBBPA) efficiently stabilizes the tetrameric structure of TTR. The X-ray crystal structure shows TBBPA binding in the thyroxine binding pocket with bromines occupying two of the three halogen binding sites. Interestingly, TBBPA binds TTR with an extremely high selectivity in human plasma, and the effect is equal to the recently approved drug tafamidis and better than diflunisal, both of which have shown therapeutic effects against FAP. TBBPA consequently present an interesting scaffold for drug design. Its absorption, metabolism, and potential side-effects are discussed.
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Affiliation(s)
- Irina Iakovleva
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Afshan Begum
- Department of Chemistry, Umeå University, Umeå, Sweden
| | | | - Alexandra Wijsekera
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
| | - Lina Nilsson
- Department of Chemistry, Umeå University, Umeå, Sweden
| | - Jin Zhang
- Department of Chemistry, Umeå University, Umeå, Sweden
| | | | | | - Anders Olofsson
- Department of Medical Biochemistry and Biophysics, Umeå University, Umeå, Sweden
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9
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Abstract
Protein misfolding and aggregation underpin several fatal neurodegenerative diseases, including Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), and frontotemporal dementia (FTD). There are no treatments that directly antagonize the protein-misfolding events that cause these disorders. Agents that reverse protein misfolding and restore proteins to native form and function could simultaneously eliminate any deleterious loss-of-function or toxic gain-of-function caused by misfolded conformers. Moreover, a disruptive technology of this nature would eliminate self-templating conformers that spread pathology and catalyze formation of toxic, soluble oligomers. Here, we highlight our efforts to engineer Hsp104, a protein disaggregase from yeast, to more effectively disaggregate misfolded proteins connected with PD, ALS, and FTD. Remarkably subtle modifications of Hsp104 primary sequence yielded large gains in protective activity against deleterious α-synuclein, TDP-43, FUS, and TAF15 misfolding. Unusually, in many cases loss of amino acid identity at select positions in Hsp104 rather than specific mutation conferred a robust therapeutic gain-of-function. Nevertheless, the misfolding and toxicity of EWSR1, an RNA-binding protein with a prion-like domain linked to ALS and FTD, could not be buffered by potentiated Hsp104 variants, indicating that further amelioration of disaggregase activity or sharpening of substrate specificity is warranted. We suggest that neuroprotection is achievable for diverse neurodegenerative conditions via surprisingly subtle structural modifications of existing chaperones.
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Affiliation(s)
- Meredith E Jackrel
- a Department of Biochemistry and Biophysics ; Perelman School of Medicine at the University of Pennsylvania ; Philadelphia , PA USA
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10
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Iakovleva I, Brännström K, Nilsson L, Gharibyan AL, Begum A, Anan I, Walfridsson M, Sauer-Eriksson AE, Olofsson A. Enthalpic Forces Correlate with the Selectivity of Transthyretin-Stabilizing Ligands in Human Plasma. J Med Chem 2015. [PMID: 26214366 DOI: 10.1021/acs.jmedchem.5b00544] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The plasma protein transthyretin (TTR) is linked to human amyloidosis. Dissociation of its native tetrameric assembly is a rate-limiting step in the conversion from a native structure into a pathological amyloidogenic fold. Binding of small molecule ligands within the thyroxine binding site of TTR can stabilize the tetrameric integrity and is a potential therapeutic approach. However, through the characterization of nine different tetramer-stabilizing ligands we found that unspecific binding to plasma components might significantly compromise ligand efficacy. Surprisingly the binding strength between a particular ligand and TTR does not correlate well with its selectivity in plasma. However, through analysis of the thermodynamic signature using isothermal titration calorimetry we discovered a better correlation between selectivity and the enthalpic component of the interaction. This is of specific interest in the quest for more efficient TTR stabilizers, but a high selectivity is an almost universally desired feature within drug design and the finding might have wide-ranging implications for drug design.
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Affiliation(s)
- Irina Iakovleva
- Department of Medical Biochemistry and Biophysics, Umeå University , 901 87 Umeå, Sweden
| | - Kristoffer Brännström
- Department of Medical Biochemistry and Biophysics, Umeå University , 901 87 Umeå, Sweden
| | - Lina Nilsson
- Department of Chemistry, Umeå University , 901 87 Umeå, Sweden
| | - Anna L Gharibyan
- Department of Pharmacology and Clinical Neurosciences, Umeå University , 901 87 Umeå, Sweden
| | - Afshan Begum
- Department of Chemistry, Umeå University , 901 87 Umeå, Sweden
| | - Intissar Anan
- Department of Public Health and Clinical Medicine, Umeå University , 901 87 Umeå, Sweden
| | - Malin Walfridsson
- Department of Medical Biochemistry and Biophysics, Umeå University , 901 87 Umeå, Sweden
| | | | - Anders Olofsson
- Department of Medical Biochemistry and Biophysics, Umeå University , 901 87 Umeå, Sweden
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11
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Extracellular remodeling in patients with wild-type amyloidosis consuming epigallocatechin-3-gallate: preliminary results of T1 mapping by cardiac magnetic resonance imaging in a small single center study. Clin Res Cardiol 2015; 104:640-7. [PMID: 25855392 DOI: 10.1007/s00392-015-0826-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2014] [Accepted: 02/12/2015] [Indexed: 12/21/2022]
Abstract
OBJECTIVES T1 mapping by cardiac magnetic resonance imaging (CMR) is able to determine the extracellular volume fraction. Wild-type transthyretin amyloidosis (WT-ATTR) is characterized by extracellular amyloid deposition in the heart. Recent reports indicated a reduction of left ventricular (LV) myocardial mass in WT-ATTR after consumption of epigallocatechin-3-gallate, the main catechin in green tea. It remained unclear, whether reduction of LV myocardial mass reflects decrease of amyloid load or progressive atrophy of cardiomyocytes. METHODS This study included 7 male patients with CMR repetitively performed before and 12 months after daily consumption of green tea extract (600 mg epigallocatechin-3-gallate). Short axis slices as well as 2-, 3-, and 4-chamber views were acquired using SSFP sequences. T1 mapping was created out of 11 mid-ventricular short axis views with increasing inversion times using a single breath-hold modified look-locker inversion recovery sequence before and 15 min after Gadolinium contrast administration. RESULTS After 12 months, a significant decrease of LV myocardial mass [198 (160; 212) vs. 180 (142; 204) g; p < 0.05] was observed. Moreover, a significant decrease of native [T1 1110 (1072; 1150) ms vs. 1080 (970; 1101), p < 0.05 or p = 0.03] was noticed. The calculated extracellular volume decreased in 5 patients (62.5%) by 7% and increased in 2 patients (37.5%) by 9.5%, in trend resulting in a (not significant) decrease of median ECV by 2.4%. Left ventricular ejection fraction (LVEF) [57 (48; 65) vs. 55 (47; 64) %; p = 0.3] remained unchanged. CONCLUSIONS This study provided further evidence of LV myocardial mass reduction in patients with WT-ATTR daily consuming green tea extract. Additionally, this study gave first insights into the histomorphological correlate of LV mass reduction using T1 mapping. LV mass reduction appeared to be rather due to a decrease of amyloid load than atrophy of cardiomyocytes.
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12
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Abstract
Amyloid fibrils are self-propagating entities that spread pathology in several devastating disorders including Alzheimer's disease (AD). In AD, amyloid-β (Aβ) peptides form extracellular plaques that contribute to cognitive decline. One potential therapeutic strategy is to develop inhibitors that prevent Aβ misfolding into proteotoxic conformers. Here, we design specific aromatic foldamers, synthetic polymers with an aromatic salicylamide (Sal) or 3-amino benzoic acid (Benz) backbone, short length (four repetitive units), basic arginine (Arg), lysine (Lys) or citrulline (Cit) side chains, and various N- and C-terminal groups that prevent spontaneous and seeded Aβ fibrillization. Ac-Sal-(Lys-Sal)3-CONH2 and Sal-(Lys-Sal)3-CONH2 selectively inhibited Aβ42 fibrillization, but were ineffective against Aβ43, an overlooked species that is highly neurotoxic and frequently deposited in AD brains. By contrast, (Arg-Benz)4-CONH2 and (Arg-Sal)3-(Cit-Sal)-CONH2 prevented spontaneous and seeded Aβ42 and Aβ43 fibrillization. Importantly, (Arg-Sal)3-(Cit-Sal)-CONH2 inhibited formation of toxic Aβ42 and Aβ43 oligomers and proteotoxicity. None of these foldamers inhibited Sup35 prionogenesis, but Sal-(Lys-Sal)3-CONH2 delayed aggregation of fused in sarcoma (FUS), an RNA-binding protein with a prion-like domain connected with amyotrophic lateral sclerosis and frontotemporal dementia. We establish that inhibitors of Aβ42 fibrillization do not necessarily inhibit Aβ43 fibrillization. Moreover, (Arg-Sal)3-(Cit-Sal)-CONH2 inhibits formation of toxic Aβ conformers and seeding activity, properties that could have therapeutic utility.
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