Browsing by Author "Kluve-Beckerman, Barbara"

Now showing 1 - 6 of 6
  • Thumbnail Image
    Item
    Amyloid fibril polymorphism in the heart of an ATTR amyloidosis patient with polyneuropathy attributed to the V122Δ variant
    (bioRxiv, 2024-05-10) Ahmed, Yasmin; Nguyen, Binh An; Afrin, Shumaila; Singh, Virender; Evers, Bret; Singh, Preeti; Pedretti, Rose; Wang, Lanie; Bassett, Parker; Fernandez-Ramirez, Maria del Carmen; Pekala, Maja; Kluve-Beckerman, Barbara; Saelices, Lorena; Pathology and Laboratory Medicine, School of Medicine
    ATTR amyloidosis is a phenotypically heterogeneous disease characterized by the pathological deposition of transthyretin in the form of amyloid fibrils into various organs. ATTR amyloidosis may stem from mutations in variant (ATTRv) amyloidosis, or aging in wild-type (ATTRwt) amyloidosis. ATTRwt generally manifests as a cardiomyopathy phenotype, whereas ATTRv may present as polyneuropathy, cardiomyopathy, or mixed, in combination with many other symptoms deriving from secondary organ involvement. Over 130 different mutational variants of transthyretin have been identified, many of them being linked to specific disease symptoms. Yet, the role of these mutations in the differential disease manifestation remains elusive. Using cryo-electron microscopy, here we structurally characterized fibrils from the heart of an ATTRv patient carrying the V122Δ mutation, predominantly associated with polyneuropathy. Our results show that these fibrils are polymorphic, presenting as both single and double filaments. Our study alludes to a structural connection contributing to phenotypic variation in ATTR amyloidosis, as polymorphism in ATTR fibrils may manifest in patients with predominantly polyneuropathic phenotypes.
  • Thumbnail Image
    Item
    ATTRv-V30M Type A amyloid fibrils from heart and nerves exhibit structural homogeneity
    (bioRxiv, 2024-05-14) Nguyen, Binh An; Afrin, Shumaila; Yakubovska, Anna; Singh, Virender; Alicea, Jaime Vaquer; Kunach, Peter; Singh, Preeti; Pekala, Maja; Ahmed, Yasmin; Fernandez-Ramirez, Maria del Carmen; Cabrera Hernandez, Luis O.; Pedretti, Rose; Bassett, Parker; Wang, Lanie; Lemoff, Andrew; Villalon, Layla; Kluve-Beckerman, Barbara; Saelices, Lorena; Pathology and Laboratory Medicine, School of Medicine
    ATTR amyloidosis is a systemic disease characterized by the deposition of amyloid fibrils made of transthyretin, a protein integral to transporting retinol and thyroid hormones. Transthyretin is primarily produced by the liver and circulates in blood as a tetramer. The retinal epithelium also secretes transthyretin, which is secreted to the vitreous humor of the eye. Because of mutations or aging, transthyretin can dissociate into amyloidogenic monomers triggering amyloid fibril formation. The deposition of transthyretin amyloid fibrils in the myocardium and peripheral nerves causes cardiomyopathies and neuropathies, respectively. Using cryo-electron microscopy, here we determined the structures of amyloid fibrils extracted from cardiac and nerve tissues of an ATTRv-V30M patient. We found that fibrils from both tissues share a consistent structural conformation, similar to the previously described structure of cardiac fibrils from an individual with the same genotype, but different from the fibril structure obtained from the vitreous humor. Our study hints to a uniform fibrillar architecture across different tissues within the same individual, only when the source of transthyretin is the liver. Moreover, this study provides the first description of ATTR fibrils from the nerves of a patient and enhances our understanding of the role of deposition site and protein production site in shaping the fibril structure in ATTRv-V30M amyloidosis.
  • Thumbnail Image
    Item
    A cell-based high-throughput screening method to directly examine transthyretin amyloid fibril formation at neutral pH
    (Elsevier, 2019-07-19) Ueda, Mitsuharu; Okada, Masamitsu; Mizuguchi, Mineyuki; Kluve-Beckerman, Barbara; Kanenawa, Kyosuke; Isoguchi, Aito; Misumi, Yohei; Tasaki, Masayoshi; Ueda, Akihiko; Kanai, Akinori; Sasaki, Ryoko; Masuda, Teruaki; Inoue, Yasuteru; Nomura, Toshiya; Shinriki, Satoru; Shuto, Tsuyoshi; Kai, Hirofumi; Yamashita, Taro; Matsui, Hirotaka; Benson, Merrill D.; Ando, Yukio; Pathology and Laboratory Medicine, School of Medicine
    Transthyretin (TTR) is a major amyloidogenic protein associated with hereditary (ATTRm) and nonhereditary (ATTRwt) intractable systemic transthyretin amyloidosis. The pathological mechanisms of ATTR-associated amyloid fibril formation are incompletely understood, and there is a need for identifying compounds that target ATTR. C-terminal TTR fragments are often present in amyloid-laden tissues of most patients with ATTR amyloidosis, and on the basis of in vitro studies, these fragments have been proposed to play important roles in amyloid formation. Here, we found that experimentally-formed aggregates of full-length TTR are cleaved into C-terminal fragments, which were also identified in patients' amyloid-laden tissues and in SH-SY5Y neuronal and U87MG glial cells. We observed that a 5-kDa C-terminal fragment of TTR, TTR81–127, is highly amyloidogenic in vitro, even at neutral pH. This fragment formed amyloid deposits and induced apoptosis and inflammatory gene expression also in cultured cells. Using the highly amyloidogenic TTR81–127 fragment, we developed a cell-based high-throughput screening method to discover compounds that disrupt TTR amyloid fibrils. Screening a library of 1280 off-patent drugs, we identified two candidate repositioning drugs, pyrvinium pamoate and apomorphine hydrochloride. Both drugs disrupted patient-derived TTR amyloid fibrils ex vivo, and pyrvinium pamoate also stabilized the tetrameric structure of TTR ex vivo in patient plasma. We conclude that our TTR81–127–based screening method is very useful for discovering therapeutic drugs that directly disrupt amyloid fibrils. We propose that repositioning pyrvinium pamoate and apomorphine hydrochloride as TTR amyloid-disrupting agents may enable evaluation of their clinical utility for managing ATTR amyloidosis.
  • Thumbnail Image
    Item
    Cryo-EM confirms a common fibril fold in the heart of four patients with ATTRwt amyloidosis
    (bioRxiv, 2024-03-09) Nguyen, Binh An; Singh, Virender; Afrin, Shumaila; Singh, Preeti; Pekala, Maja; Ahmed, Yasmin; Pedretti, Rose; Canepa, Jacob; Lemoff, Andrew; Kluve-Beckerman, Barbara; Wydorski, Pawel; Chhapra, Farzeen; Saelices, Lorena; Pathology and Laboratory Medicine, School of Medicine
    ATTR amyloidosis results from the conversion of transthyretin into amyloid fibrils that deposit in tissues causing organ failure and death. This conversion is facilitated by mutations in ATTRv amyloidosis, or aging in ATTRwt amyloidosis. ATTRv amyloidosis exhibits extreme phenotypic variability, whereas ATTRwt amyloidosis presentation is consistent and predictable. Previously, we found an unprecedented structural variability in cardiac amyloid fibrils from polyneuropathic ATTRv-I84S patients. In contrast, cardiac fibrils from five genotypically-different patients with cardiomyopathy or mixed phenotypes are structurally homogeneous. To understand fibril structure's impact on phenotype, it is necessary to study the fibrils from multiple patients sharing genotype and phenotype. Here we show the cryo-electron microscopy structures of fibrils extracted from four cardiomyopathic ATTRwt amyloidosis patients. Our study confirms that they share identical conformations with minimal structural variability, consistent with their homogenous clinical presentation. Our study contributes to the understanding of ATTR amyloidosis biopathology and calls for further studies.
  • Thumbnail Image
    Item
    Hereditary systemic immunoglobulin light-chain amyloidosis
    (American Society of Hematology, 2015-05) Benson, Merrill D.; Liepnieks, Juris J.; Kluve-Beckerman, Barbara; Department of Pathology and Laboratory Medicine, IU School of Medicine
    Several members of a family died from renal failure as a result of systemic amyloidosis. Extensive studies to detect previously documented gene mutations associated with amyloidosis failed to identify a causative factor. In search of the genetic basis for this syndrome, amyloid fibrils were isolated from renal tissue of a member of the kin who died while on renal dialysis. Amino acid sequencing of isolated amyloid protein identified sequences compatible with the constant region of the immunoglobulin κ light-chain. Isolation and characterization of κ light-chain protein from serum of an affected member of the kindred revealed mutation in the constant region of κ light-chain, with cysteine replacing serine at amino acid residue 131. This mutation (Ser131Cys) was confirmed by DNA analysis, which identified a single-base change of cytosine to guanine at the second position of codon 131 of the κ light-chain gene (TCT131TGT). DNA analysis of members of the extended family revealed transmission of the Ser131Cys mutation and association with systemic amyloidosis. This amyloid light-chain (AL) amyloidosis, which is a hereditary type of amyloidosis and not the result of a monoclonal plasma cell dyscrasia, may be misdiagnosed and lead to inappropriate chemotherapy.
  • Thumbnail Image
    Item
    A transgenic mouse model reproduces human hereditary systemic amyloidosis
    (Elsevier, 2019) Chabert, Michèle; Rousset, Xavier; Colombat, Magali; Lacasa, Michel; Kakanakou, Hermine; Bourderioux, Mathilde; Brousset, Pierre; Burlet-Schiltz, Odile; Liepnieks, Juris J.; Kluve-Beckerman, Barbara; Lambert, Gilles; Châtelet, François P.; Benson, Merrill D.; Kalopissis, Athina D.; Pathology and Laboratory Medicine, School of Medicine
    Amyloidoses are rare life-threatening diseases caused by protein misfolding of normally soluble proteins. The fatal outcome is predominantly due to renal failure and/or cardiac dysfunction. Because amyloid fibrils formed by all amyloidogenic proteins share structural similarity, amyloidoses may be studied in transgenic models expressing any amyloidogenic protein. Here we generated transgenic mice expressing an amyloidogenic variant of human apolipoprotein AII, a major protein of high density lipoprotein. According to amyloid nomenclature this variant was termed STOP78SERApoAII. STOP78SER-APOA2 expression at the physiological level spontaneously induced systemic amyloidosis in all mice with full-length mature STOP78SER-ApoAII identified as the amyloidogenic protein. Amyloid deposits stained with Congo red, were extracellular, and consisted of fibrils of approximately 10 nm diameter. Renal glomerular amyloidosis was a major feature with onset of renal insufficiency occurring in mice older than six months of age. The liver, heart and spleen were also greatly affected. Expression of STOP78SER-APOA2 in liver and intestine in mice of the K line but not in other amyloid-laden organs showed they present systemic amyloidosis. The amyloid burden was a function of STOP78SER-APOA2 expression and age of the mice with amyloid deposition starting in two-month old high-expressing mice that died from six months onwards. Because STOP78SER-ApoAII conserved adequate lipid binding capacity as shown by high STOP78SER-ApoAII amounts in high density lipoprotein of young mice, its decrease in circulation with age suggests preferential deposition into preformed fibrils. Thus, our mouse model faithfully reproduces early-onset hereditary systemic amyloidosis and is ideally suited to devise and test novel therapies.