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Browsing by Author "Singh, Virender"
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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 MedicineATTR 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.Item Structural polymorphism of amyloid fibrils in ATTR amyloidosis revealed by cryo-electron microscopy(Springer Nature, 2024-01-17) Nguyen, Binh An; Singh, Virender; Afrin, Shumaila; Yakubovska, Anna; Wang, Lanie; Ahmed, Yasmin; Pedretti, Rose; Fernandez-Ramirez, Maria del Carmen; Singh, Preeti; Pękała, Maja; Cabrera Hernandez, Luis O.; Kumar, Siddharth; Lemoff, Andrew; Gonzalez-Prieto, Roman; Sawaya, Michael R.; Eisenberg, David S.; Benson, Merrill Douglas; Saelices, Lorena; Pathology and Laboratory Medicine, School of MedicineATTR amyloidosis is caused by the deposition of transthyretin in the form of amyloid fibrils in virtually every organ of the body, including the heart. This systemic deposition leads to a phenotypic variability that has not been molecularly explained yet. In brain amyloid conditions, previous studies suggest an association between clinical phenotype and the molecular structures of their amyloid fibrils. Here we investigate whether there is such an association in ATTRv amyloidosis patients carrying the mutation I84S. Using cryo-electron microscopy, we determined the structures of cardiac fibrils extracted from three ATTR amyloidosis patients carrying the ATTRv-I84S mutation, associated with a consistent clinical phenotype. We found that in each ATTRv-I84S patient, the cardiac fibrils exhibited different local conformations, and these variations can co-exist within the same fibril. Our finding suggests that one amyloid disease may associate with multiple fibril structures in systemic amyloidoses, calling for further studies.