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Wang S, Ma S, Li H, Dao M, Li X, Karniadakis GE. Two-component macrophage model for active phagocytosis with pseudopod formation. Biophys J 2024; 123:1069-1084. [PMID: 38532625 PMCID: PMC11079866 DOI: 10.1016/j.bpj.2024.03.026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Revised: 11/20/2023] [Accepted: 03/21/2024] [Indexed: 03/28/2024] Open
Abstract
Macrophage phagocytosis is critical for the immune response, homeostasis regulation, and tissue repair. This intricate process involves complex changes in cell morphology, cytoskeletal reorganization, and various receptor-ligand interactions controlled by mechanical constraints. However, there is a lack of comprehensive theoretical and computational models that investigate the mechanical process of phagocytosis in the context of cytoskeletal rearrangement. To address this issue, we propose a novel coarse-grained mesoscopic model that integrates a fluid-like cell membrane and a cytoskeletal network to study the dynamic phagocytosis process. The growth of actin filaments results in the formation of long and thin pseudopods, and the initial cytoskeleton can be disassembled upon target entry and reconstructed after phagocytosis. Through dynamic changes in the cytoskeleton, our macrophage model achieves active phagocytosis by forming a phagocytic cup utilizing pseudopods in two distinct ways. We have developed a new algorithm for modifying membrane area to prevent membrane rupture and ensure sufficient surface area during phagocytosis. In addition, the bending modulus, shear stiffness, and cortical tension of the macrophage model are investigated through computation of the axial force for the tubular structure and micropipette aspiration. With this model, we simulate active phagocytosis at the cytoskeletal level and investigate the mechanical process during the dynamic interplay between macrophage and target particles.
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Affiliation(s)
- Shuo Wang
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Shuhao Ma
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou, Zhejiang, China
| | - He Li
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, Georgia
| | - Ming Dao
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - Xuejin Li
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou, Zhejiang, China.
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2
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Qiang Y, Xu M, Patel Pochron M, Jupelli M, Dao M. A framework of computer vision-enhanced microfluidic approach for automated assessment of the transient sickling kinetics in sickle red blood cells. FRONTIERS IN PHYSICS 2024; 12:1331047. [PMID: 38605818 PMCID: PMC11008125 DOI: 10.3389/fphy.2024.1331047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 04/13/2024]
Abstract
The occurrence of vaso-occlusive crisis greatly depends on the competition between the sickling delay time and the transit time of individual sickle cells, i.e., red blood cells (RBCs) from sickle cell disease (SCD) patients, while they are traversing the circulatory system. Many drugs for treating SCD work by inhibiting the polymerization of sickle hemoglobin (HbS), effectively delaying the sickling process in sickle cells (SS RBCs). Most previous studies on screening anti-sickling drugs, such as voxelotor, rely on in vitro testing of sickling characteristics, often conducted under prolonged deoxygenation for up to 1 hour. However, since the microcirculation of RBCs typically takes less than 1 minute, the results of these studies may be less accurate and less relevant for in vitro-in vivo correlation. In our current study, we introduce a computer vision-enhanced microfluidic framework designed to automatically capture the transient sickling kinetics of SS RBCs within a 1-min timeframe. Our study has successfully detected differences in the transient sickling kinetics between vehicle control and voxelotor-treated SS RBCs. This approach has the potential for broader applications in screening anti-sickling therapies.
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Affiliation(s)
- Yuhao Qiang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
| | - Mengjia Xu
- Department of Data Science, Ying Wu College of Computing, New Jersey Institute of Technology, Newark, NJ, United States
- Center for Brains, Minds and Machines, Massachusetts Institute of Technology, Cambridge, MA, United States
| | | | | | - Ming Dao
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA, United States
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3
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Zhang Y, Qiang Y, Li H, Li G, Lu L, Dao M, Karniadakis GE, Popel AS, Zhao C. Signaling-biophysical modeling unravels mechanistic control of red blood cell phagocytosis by macrophages in sickle cell disease. PNAS NEXUS 2024; 3:pgae031. [PMID: 38312226 PMCID: PMC10833451 DOI: 10.1093/pnasnexus/pgae031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2023] [Accepted: 01/09/2024] [Indexed: 02/06/2024]
Abstract
Red blood cell (RBC) aging manifests through progressive changes in cell morphology, rigidity, and expression of membrane proteins. To maintain the quality of circulating blood, splenic macrophages detect the biochemical signals and biophysical changes of RBCs and selectively clear them through erythrophagocytosis. In sickle cell disease (SCD), RBCs display alterations affecting their interaction with macrophages, leading to aberrant phagocytosis that may cause life-threatening spleen sequestration crises. To illuminate the mechanistic control of RBC engulfment by macrophages in SCD, we integrate a system biology model of RBC-macrophage signaling interactions with a biophysical model of macrophage engulfment, as well as in vitro phagocytosis experiments using the spleen-on-a-chip technology. Our modeling framework accurately predicts the phagocytosis dynamics of RBCs under different disease conditions, reveals patterns distinguishing normal and sickle RBCs, and identifies molecular targets including Src homology 2 domain-containing protein tyrosine phosphatase-1 (SHP1) and cluster of differentiation 47 (CD47)/signal regulatory protein α (SIRPα) as therapeutic targets to facilitate the controlled clearance of sickle RBCs in the spleen.
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Affiliation(s)
- Yu Zhang
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Yuhao Qiang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - He Li
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, GA 30602, USA
| | - Guansheng Li
- School of Engineering, Brown University, Providence, RI 02912, USA
| | - Lu Lu
- Department of Statistics and Data Science, Yale University, New Haven, CT 06520, USA
| | - Ming Dao
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Aleksander S Popel
- Department of Biomedical Engineering, School of Medicine, Johns Hopkins University, Baltimore, MD 21205, USA
| | - Chen Zhao
- School of Pharmacy, Nanjing Medical University, Nanjing, Jiangsu 210029, China
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4
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Raballah E, Wilding K, Anyona SB, Munde EO, Hurwitz I, Onyango CO, Ayieko C, Lambert CG, Schneider KA, Seidenberg PD, Ouma C, McMahon BH, Cheng Q, Perkins DJ. Nonsynonymous amino acid changes in the α-chain of complement component 5 influence longitudinal susceptibility to Plasmodium falciparum infections and severe malarial anemia in kenyan children. Front Genet 2022; 13:977810. [PMID: 36186473 PMCID: PMC9515573 DOI: 10.3389/fgene.2022.977810] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 08/24/2022] [Indexed: 11/13/2022] Open
Abstract
Background: Severe malarial anemia (SMA; Hb < 5.0 g/dl) is a leading cause of childhood morbidity and mortality in holoendemic Plasmodium falciparum transmission regions such as western Kenya. Methods: We investigated the relationship between two novel complement component 5 (C5) missense mutations [rs17216529:C>T, p(Val145Ile) and rs17610:C>T, p(Ser1310Asn)] and longitudinal outcomes of malaria in a cohort of Kenyan children (under 60 mos, n = 1,546). Molecular modeling was used to investigate the impact of the amino acid transitions on the C5 protein structure. Results: Prediction of the wild-type and mutant C5 protein structures did not reveal major changes to the overall structure. However, based on the position of the variants, subtle differences could impact on the stability of C5b. The influence of the C5 genotypes/haplotypes on the number of malaria and SMA episodes over 36 months was determined by Poisson regression modeling. Genotypic analyses revealed that inheritance of the homozygous mutant (TT) for rs17216529:C>T enhanced the risk for both malaria (incidence rate ratio, IRR = 1.144, 95%CI: 1.059–1.236, p = 0.001) and SMA (IRR = 1.627, 95%CI: 1.201–2.204, p = 0.002). In the haplotypic model, carriers of TC had increased risk of malaria (IRR = 1.068, 95%CI: 1.017–1.122, p = 0.009), while carriers of both wild-type alleles (CC) were protected against SMA (IRR = 0.679, 95%CI: 0.542–0.850, p = 0.001). Conclusion: Collectively, these findings show that the selected C5 missense mutations influence the longitudinal risk of malaria and SMA in immune-naïve children exposed to holoendemic P. falciparum transmission through a mechanism that remains to be defined.
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Affiliation(s)
- Evans Raballah
- University of New Mexico-Kenya Global Health Programs, Kisumu, Kenya
- Department of Medical Laboratory Sciences, School of Public Health Biomedical Sciences and Technology, Masinde Muliro University of Science and Technology, Kakamega, Kenya
- *Correspondence: Evans Raballah,
| | - Kristen Wilding
- Theoretical Biology and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, United States
| | - Samuel B. Anyona
- University of New Mexico-Kenya Global Health Programs, Kisumu, Kenya
- Department of Medical Biochemistry, School of Medicine, Maseno University, Maseno, Kenya
| | - Elly O. Munde
- University of New Mexico-Kenya Global Health Programs, Kisumu, Kenya
- Department of Clinical Medicine, School of Health Sciences, Kirinyaga University, Kerugoya, Kenya
| | - Ivy Hurwitz
- University of New Mexico, Center for Global Health, Department of Internal Medicine, Albuquerque, NM, United States
| | - Clinton O. Onyango
- University of New Mexico-Kenya Global Health Programs, Kisumu, Kenya
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno, Kenya
| | - Cyrus Ayieko
- Department of Zoology, Maseno University, Maseno, Kenya
| | - Christophe G. Lambert
- University of New Mexico, Center for Global Health, Department of Internal Medicine, Albuquerque, NM, United States
| | - Kristan A. Schneider
- Department of Applied Computer and Biosciences, University of Applied Sciences Mittweida, Mittweida, Germany
| | - Philip D. Seidenberg
- University of New Mexico, Department of Emergency Medicine, Albuquerque, NM, United States
| | - Collins Ouma
- University of New Mexico-Kenya Global Health Programs, Kisumu, Kenya
- Department of Biomedical Sciences and Technology, School of Public Health and Community Development, Maseno University, Maseno, Kenya
| | - Benjamin H. McMahon
- Theoretical Biology and Biophysics Group, Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM, United States
| | - Qiuying Cheng
- University of New Mexico, Center for Global Health, Department of Internal Medicine, Albuquerque, NM, United States
| | - Douglas J. Perkins
- University of New Mexico-Kenya Global Health Programs, Kisumu, Kenya
- University of New Mexico, Center for Global Health, Department of Internal Medicine, Albuquerque, NM, United States
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5
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Azul M, Vital EF, Lam WA, Wood DK, Beckman JD. Microfluidic methods to advance mechanistic understanding and translational research in sickle cell disease. Transl Res 2022; 246:1-14. [PMID: 35354090 PMCID: PMC9218997 DOI: 10.1016/j.trsl.2022.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Revised: 03/23/2022] [Accepted: 03/24/2022] [Indexed: 12/15/2022]
Abstract
Sickle cell disease (SCD) is caused by a single point mutation in the β-globin gene of hemoglobin, which produces an altered sickle hemoglobin (HbS). The ability of HbS to polymerize under deoxygenated conditions gives rise to chronic hemolysis, oxidative stress, inflammation, and vaso-occlusion. Herein, we review recent findings using microfluidic technologies that have elucidated mechanisms of oxygen-dependent and -independent induction of HbS polymerization and how these mechanisms elicit the biophysical and inflammatory consequences in SCD pathophysiology. We also discuss how validation and use of microfluidics in SCD provides the opportunity to advance development of numerous therapeutic strategies, including curative gene therapies.
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Affiliation(s)
- Melissa Azul
- Department of Pediatrics, Mayo Clinic, Rochester, Minnesota
| | - Eudorah F Vital
- Wallace H. Coulter Department of Biomedical Engineering and Institute for Electronics and Nanotechnology, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - Wilbur A Lam
- Wallace H. Coulter Department of Biomedical Engineering and Institute for Electronics and Nanotechnology, Georgia Institute of Technology and Emory University, Atlanta, Georgia
| | - David K Wood
- Department of Biomedical Engineering, University of Minnesota, Minneapolis, Minnesota
| | - Joan D Beckman
- Department of Medicine, Division of Hematology, Oncology and Transplantation, University of Minnesota, Minneapolis, Minnesota.
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6
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Deng YX, Chang HY, Li H. Recent Advances in Computational Modeling of Biomechanics and Biorheology of Red Blood Cells in Diabetes. Biomimetics (Basel) 2022; 7:15. [PMID: 35076493 PMCID: PMC8788472 DOI: 10.3390/biomimetics7010015] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 01/01/2022] [Accepted: 01/08/2022] [Indexed: 02/06/2023] Open
Abstract
Diabetes mellitus, a metabolic disease characterized by chronically elevated blood glucose levels, affects about 29 million Americans and more than 422 million adults all over the world. Particularly, type 2 diabetes mellitus (T2DM) accounts for 90-95% of the cases of vascular disease and its prevalence is increasing due to the rising obesity rates in modern societies. Although multiple factors associated with diabetes, such as reduced red blood cell (RBC) deformability, enhanced RBC aggregation and adhesion to the endothelium, as well as elevated blood viscosity are thought to contribute to the hemodynamic impairment and vascular occlusion, clinical or experimental studies cannot directly quantify the contributions of these factors to the abnormal hematology in T2DM. Recently, computational modeling has been employed to dissect the impacts of the aberrant biomechanics of diabetic RBCs and their adverse effects on microcirculation. In this review, we summarize the recent advances in the developments and applications of computational models in investigating the abnormal properties of diabetic blood from the cellular level to the vascular level. We expect that this review will motivate and steer the development of new models in this area and shift the attention of the community from conventional laboratory studies to combined experimental and computational investigations, aiming to provide new inspirations for the development of advanced tools to improve our understanding of the pathogenesis and pathology of T2DM.
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Affiliation(s)
- Yi-Xiang Deng
- School of Engineering, Brown University, Providence, RI 02912, USA;
| | - Hung-Yu Chang
- Division of Applied Mathematics, Brown University, Providence, RI 02912, USA;
| | - He Li
- Center for Biomedical Engineering, Brown University, Providence, RI 02912, USA
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7
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8
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Yang DS, Saeedi A, Davtyan A, Fathi M, Sherman MB, Safari MS, Klindziuk A, Barton MC, Varadarajan N, Kolomeisky AB, Vekilov PG. Mesoscopic protein-rich clusters host the nucleation of mutant p53 amyloid fibrils. Proc Natl Acad Sci U S A 2021; 118:e2015618118. [PMID: 33653952 PMCID: PMC7958401 DOI: 10.1073/pnas.2015618118] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The protein p53 is a crucial tumor suppressor, often called "the guardian of the genome"; however, mutations transform p53 into a powerful cancer promoter. The oncogenic capacity of mutant p53 has been ascribed to enhanced propensity to fibrillize and recruit other cancer fighting proteins in the fibrils, yet the pathways of fibril nucleation and growth remain obscure. Here, we combine immunofluorescence three-dimensional confocal microscopy of human breast cancer cells with light scattering and transmission electron microscopy of solutions of the purified protein and molecular simulations to illuminate the mechanisms of phase transformations across multiple length scales, from cellular to molecular. We report that the p53 mutant R248Q (R, arginine; Q, glutamine) forms, both in cancer cells and in solutions, a condensate with unique properties, mesoscopic protein-rich clusters. The clusters dramatically diverge from other protein condensates. The cluster sizes are decoupled from the total cluster population volume and independent of the p53 concentration and the solution concentration at equilibrium with the clusters varies. We demonstrate that the clusters carry out a crucial biological function: they host and facilitate the nucleation of amyloid fibrils. We demonstrate that the p53 clusters are driven by structural destabilization of the core domain and not by interactions of its extensive unstructured region, in contradistinction to the dense liquids typical of disordered and partially disordered proteins. Two-step nucleation of mutant p53 amyloids suggests means to control fibrillization and the associated pathologies through modifying the cluster characteristics. Our findings exemplify interactions between distinct protein phases that activate complex physicochemical mechanisms operating in biological systems.
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Affiliation(s)
- David S Yang
- William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204
| | - Arash Saeedi
- William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204
| | - Aram Davtyan
- Department of Chemistry, Rice University, Houston, TX 77251
| | - Mohsen Fathi
- William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204
| | - Michael B Sherman
- Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555
- Sealy Center for Structural Biology and Molecular Biophysics, University of Texas Medical Branch, Galveston, TX 77555
| | - Mohammad S Safari
- William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544
| | | | - Michelle C Barton
- Department of Epigenetics and Molecular Carcinogenesis, The University of Texas MD Anderson Cancer Center, Houston, TX 77030
| | - Navin Varadarajan
- William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204
| | - Anatoly B Kolomeisky
- Department of Chemistry, Rice University, Houston, TX 77251
- Center for Theoretical Biological Physics, Rice University, Houston, TX 77251
| | - Peter G Vekilov
- William A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, TX 77204;
- Department of Chemistry, University of Houston, Houston, TX 77204
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9
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Aich A, Lamarre Y, Sacomani DP, Kashima S, Covas DT, de la Torre LG. Microfluidics in Sickle Cell Disease Research: State of the Art and a Perspective Beyond the Flow Problem. Front Mol Biosci 2021; 7:558982. [PMID: 33763448 PMCID: PMC7982466 DOI: 10.3389/fmolb.2020.558982] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/24/2020] [Indexed: 01/21/2023] Open
Abstract
Sickle cell disease (SCD) is the monogenic hemoglobinopathy where mutated sickle hemoglobin molecules polymerize to form long fibers under deoxygenated state and deform red blood cells (RBCs) into predominantly sickle form. Sickled RBCs stick to the vascular bed and obstruct blood flow in extreme conditions, leading to acute painful vaso-occlusion crises (VOCs) – the leading cause of mortality in SCD. Being a blood disorder of deformed RBCs, SCD manifests a wide-range of organ-specific clinical complications of life (in addition to chronic pain) such as stroke, acute chest syndrome (ACS) and pulmonary hypertension in the lung, nephropathy, auto-splenectomy, and splenomegaly, hand-foot syndrome, leg ulcer, stress erythropoiesis, osteonecrosis and osteoporosis. The physiological inception for VOC was initially thought to be only a fluid flow problem in microvascular space originated from increased viscosity due to aggregates of sickled RBCs; however, over the last three decades, multiple molecular and cellular mechanisms have been identified that aid the VOC in vivo. Activation of adhesion molecules in vascular endothelium and on RBC membranes, activated neutrophils and platelets, increased viscosity of the blood, and fluid physics driving sickled and deformed RBCs to the vascular wall (known as margination of flow) – all of these come together to orchestrate VOC. Microfluidic technology in sickle research was primarily adopted to benefit from mimicking the microvascular network to observe RBC flow under low oxygen conditions as models of VOC. However, over the last decade, microfluidics has evolved as a valuable tool to extract biophysical characteristics of sickle red cells, measure deformability of sickle red cells under simulated oxygen gradient and shear, drug testing, in vitro models of intercellular interaction on endothelialized or adhesion molecule-functionalized channels to understand adhesion in sickle microenvironment, characterizing biomechanics and microrheology, biomarker identification, and last but not least, for developing point-of-care diagnostic technologies for low resource setting. Several of these platforms have already demonstrated true potential to be translated from bench to bedside. Emerging microfluidics-based technologies for studying heterotypic cell–cell interactions, organ-on-chip application and drug dosage screening can be employed to sickle research field due to their wide-ranging advantages.
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Affiliation(s)
- Anupam Aich
- Intel Corporation, Hillsboro, OR, United States
| | - Yann Lamarre
- Center for Cell-based Therapy, Regional Blood Center of Ribeirão Preto, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Daniel Pereira Sacomani
- Department of Material and Bioprocess Engineering, School of Chemical Engineering, University of Campinas (UNICAMP), Campinas, Brazil
| | - Simone Kashima
- Center for Cell-based Therapy, Regional Blood Center of Ribeirão Preto, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Dimas Tadeu Covas
- Center for Cell-based Therapy, Regional Blood Center of Ribeirão Preto, Ribeirão Preto Medical School, University of São Paulo, Ribeirão Preto, Brazil
| | - Lucimara Gaziola de la Torre
- Department of Material and Bioprocess Engineering, School of Chemical Engineering, University of Campinas (UNICAMP), Campinas, Brazil
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10
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Allosteric control of hemoglobin S fiber formation by oxygen and its relation to the pathophysiology of sickle cell disease. Proc Natl Acad Sci U S A 2020; 117:15018-15027. [PMID: 32527859 PMCID: PMC7334536 DOI: 10.1073/pnas.1922004117] [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] [Indexed: 02/02/2023] Open
Abstract
The pathology of sickle cell disease is caused by polymerization of the abnormal hemoglobin S upon deoxygenation in the tissues to form fibers in red cells, causing them to deform and occlude the circulation. Drugs that allosterically shift the quaternary equilibrium from the polymerizing T quaternary structure to the nonpolymerizing R quaternary structure are now being developed. Here we update our understanding on the allosteric control of fiber formation at equilibrium by showing how the simplest extension of the classic quaternary two-state allosteric model of Monod, Wyman, and Changeux to include tertiary conformational changes provides a better quantitative description. We also show that if fiber formation is at equilibrium in vivo, the vast majority of cells in most tissues would contain fibers, indicating that it is unlikely that the disease would be survivable once the nonpolymerizing fetal hemoglobin has been replaced by adult hemoglobin S at about 1 y after birth. Calculations of sickling times, based on a recently discovered universal relation between the delay time prior to fiber formation and supersaturation, show that in vivo fiber formation is very far from equilibrium. Our analysis indicates that patients survive because the delay period allows the majority of cells to escape the small vessels of the tissues before fibers form. The enormous sensitivity of the duration of the delay period to intracellular hemoglobin composition also explains why sickle trait, the heterozygous condition, and the compound heterozygous condition of hemoglobin S with pancellular hereditary persistence of fetal hemoglobin are both relatively benign conditions.
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11
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Eaton WA. Hemoglobin S polymerization and sickle cell disease: A retrospective on the occasion of the 70th anniversary of Pauling's Science paper. Am J Hematol 2020; 95:205-211. [PMID: 31763707 PMCID: PMC7003899 DOI: 10.1002/ajh.25687] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Accepted: 11/05/2019] [Indexed: 12/12/2022]
Abstract
70 years ago, Linus Pauling, the legendary genius of 20th century chemistry, published his famous work on the molecular cause of sickle cell disease, a paper that gave birth to what is now called molecular medicine. In this paper, Pauling left important questions unanswered that have motivated an enormous amount of scientific and clinical research since then. This retrospective discusses the basic science studies that have answered those questions directly related to the kinetics and thermodynamics of hemoglobin S polymerization.
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Affiliation(s)
- William A. Eaton
- Laboratory of Chemical PhysicsNational Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health Bethesda Maryland
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12
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Olubiyi OO, Olagunju MO, Strodel B. Rational Drug Design of Peptide-Based Therapies for Sickle Cell Disease. Molecules 2019; 24:molecules24244551. [PMID: 31842406 PMCID: PMC6943517 DOI: 10.3390/molecules24244551] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 12/08/2019] [Accepted: 12/09/2019] [Indexed: 11/16/2022] Open
Abstract
Sickle cell disease (SCD) is a group of inherited disorders affecting red blood cells, which is caused by a single mutation that results in substitution of the amino acid valine for glutamic acid in the sixth position of the β-globin chain of hemoglobin. These mutant hemoglobin molecules, called hemoglobin S, can polymerize upon deoxygenation, causing erythrocytes to adopt a sickled form and to suffer hemolysis and vaso-occlusion. Until recently, only two drug therapies for SCD, which do not even fully address the manifestations of SCD, were approved by the United States (US) Food and Drug Administration. A third treatment was newly approved, while a monoclonal antibody preventing vaso-occlusive crises is also now available. The complex nature of SCD manifestations provides multiple critical points where drug discovery efforts can be and have been directed. These notwithstanding, the need for new therapeutic approaches remains high and one of the recent efforts includes developments aimed at inhibiting the polymerization of hemoglobin S. This review focuses on anti-sickling approaches using peptide-based inhibitors, ranging from individual amino acid dipeptides investigated 30–40 years ago up to more promising 12- and 15-mers under consideration in recent years.
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Affiliation(s)
- Olujide O. Olubiyi
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany; (M.O.O.); (B.S.)
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife 220282, Nigeria
- Correspondence:
| | - Maryam O. Olagunju
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany; (M.O.O.); (B.S.)
| | - Birgit Strodel
- Institute of Complex Systems: Structural Biochemistry, Forschungszentrum Jülich, 52425 Jülich, Germany; (M.O.O.); (B.S.)
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225 Düsseldorf, Germany
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