scholarly journals Sickling Cells, Cyclic Nucleotides, and Protein Kinases: The Pathophysiology of Urogenital Disorders in Sickle Cell Anemia

Anemia ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-13 ◽  
Author(s):  
Mário Angelo Claudino ◽  
Kleber Yotsumoto Fertrin

Sickle cell anemia is one of the best studied inherited diseases, and despite being caused by a single point mutation in theHBBgene, multiple pleiotropic effects of the abnormal hemoglobin S production range from vaso-occlusive crisis, stroke, and pulmonary hypertension to osteonecrosis and leg ulcers. Urogenital function is not spared, and although priapism is most frequently remembered, other related clinical manifestations have been described, such as nocturia, enuresis, increased frequence of lower urinary tract infections, urinary incontinence, hypogonadism, and testicular infarction. Studies on sickle cell vaso-occlusion and priapism using bothin vitroandin vivomodels have shed light on the pathogenesis of some of these events. The authors review what is known about the deleterious effects of sickling on the genitourinary tract and how the role of cyclic nucleotides signaling and protein kinases may help understand the pathophysiology underlying these manifestations and develop novel therapies in the setting of urogenital disorders in sickle cell disease.

Haematologica ◽  
2021 ◽  
Author(s):  
Osheiza Abdulmalik ◽  
Noureldien H. E. Darwish ◽  
Vandhana Muralidharan-Chari ◽  
Maii Abu Taleb ◽  
Shaker A. Mousa

Sickle cell disease (SCD) is an autosomal recessive genetic disease caused by a single point mutation, resulting in abnormal sickle hemoglobin (HbS). During hypoxia or dehydration, HbS polymerizes to form insoluble aggregates and induces sickling of red blood cells (RBCs). RBC sickling increases adhesiveness of RBCs to alter the rheological properties of the blood and triggers inflammatory responses, leading to hemolysis and vaso-occlusive crisis sequelae. Unfractionated heparin (UFH) and low-molecular weight heparins (LMWH) have been suggested as treatments to relieve coagulation complications in SCD. However, they are associated with bleeding complications after repeated dosing. An alternative sulfated nonanticoagulant heparin derivative (S-NACH) was previously reported to have none to low systemic anticoagulant activity and no bleeding side effects, and it interfered with P-selectindependent binding of sickle cells to endothelial cells, with concomitant decrease in the levels of adhesion biomarkers in SCD mice. S-NACH has been further engineered and structurally enhanced to bind with and modify HbS to directly inhibit sickling, thus employing a multimodal approach. Here, we show that S-NACH can (i) directly engage in Schiff-base reactions with HbS to decrease RBC sickling under both normoxia and hypoxia in vitro, ii) prolong the survival of SCD mice under hypoxia, and (iii) regulate the altered steady state levels of pro- and antiinflammatory cytokines. Thus, our proof of concept in vitro and in vivo preclinical studies demonstrate that the multimodal S-NACH is a highly promising candidate for development into an improved and optimized alternative to LMWHs for the treatment of patients with SCD.


Bionatura ◽  
2019 ◽  
Vol 02 (Bionatura Conference Serie) ◽  
Author(s):  
María Belén Paredes ◽  
María Eugenia Sulen

Sickle cell disease (SCD) is a group of hereditary disorders caused by a single point mutation in the β-globin gene. This mutation results in the formation of a mutated hemoglobin S (HbS) and the consequent sickle phenotype of erythrocytes. SCD is common in regions of malaria endemicity. However, changes in population dynamics enabled the movement of the mutated gene to other areas such as North America and Europe. Sickle cell anemia (SCA) is the most severe form of SCD and affects millions of people around the globe. The clinical manifestations of SCA arise primarily from the polymerization of deoxygenated hemoglobin S (deoxyHbS) leading to vascular occlusion and hemolytic anemia. Clinical complications of the disease are derived from deoxyHbS polymerization, but there are several therapeutic strategies to reduce the severity of the symptoms. Gene therapy has arisen as a new therapeutic approach aimed to cure rather than to treat the symptomatology of SCA by targeting the altered β-globin gene for gene correction.


Pathogens ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1435
Author(s):  
Divya Beri ◽  
Manpreet Singh ◽  
Marilis Rodriguez ◽  
Karina Yazdanbakhsh ◽  
Cheryl Ann Lobo

Babesia is an intraerythrocytic, obligate Apicomplexan parasite that has, in the last century, been implicated in human infections via zoonosis and is now widespread, especially in parts of the USA and Europe. It is naturally transmitted by the bite of a tick, but transfused blood from infected donors has also proven to be a major source of transmission. When infected, most humans are clinically asymptomatic, but the parasite can prove to be lethal when it infects immunocompromised individuals. Hemolysis and anemia are two common symptoms that accompany many infectious diseases, and this is particularly true of parasitic diseases that target red cells. Clinically, this becomes an acute problem for subjects who are prone to hemolysis and depend on frequent transfusions, like patients with sickle cell anemia or thalassemia. Little is known about Babesia’s pathogenesis in these hemoglobinopathies, and most parallels are drawn from its evolutionarily related Plasmodium parasite which shares the same environmental niche, the RBCs, in the human host. In vitro as well as in vivo Babesia-infected mouse sickle cell disease (SCD) models support the inhibition of intra-erythrocytic parasite proliferation, but mechanisms driving the protection of such hemoglobinopathies against infection are not fully studied. This review provides an overview of our current knowledge of Babesia infection and hemoglobinopathies, focusing on possible mechanisms behind this parasite resistance and the clinical repercussions faced by Babesia-infected human hosts harboring mutations in their globin gene.


mBio ◽  
2016 ◽  
Vol 7 (5) ◽  
Author(s):  
Ana R. Pereira ◽  
Jen Hsin ◽  
Ewa Król ◽  
Andreia C. Tavares ◽  
Pierre Flores ◽  
...  

ABSTRACT A mechanistic understanding of the determination and maintenance of the simplest bacterial cell shape, a sphere, remains elusive compared with that of more complex shapes. Cocci seem to lack a dedicated elongation machinery, and a spherical shape has been considered an evolutionary dead-end morphology, as a transition from a spherical to a rod-like shape has never been observed in bacteria. Here we show that a Staphylococcus aureus mutant (M5) expressing the ftsZ G193D allele exhibits elongated cells. Molecular dynamics simulations and in vitro studies indicate that FtsZ G193D filaments are more twisted and shorter than wild-type filaments. In vivo , M5 cell wall deposition is initiated asymmetrically, only on one side of the cell, and progresses into a helical pattern rather than into a constricting ring as in wild-type cells. This helical pattern of wall insertion leads to elongation, as in rod-shaped cells. Thus, structural flexibility of FtsZ filaments can result in an FtsZ-dependent mechanism for generating elongated cells from cocci. IMPORTANCE The mechanisms by which bacteria generate and maintain even the simplest cell shape remain an elusive but fundamental question in microbiology. In the absence of examples of coccus-to-rod transitions, the spherical shape has been suggested to be an evolutionary dead end in morphogenesis. We describe the first observation of the generation of elongated cells from truly spherical cocci, occurring in a Staphylococcus aureus mutant containing a single point mutation in its genome, in the gene encoding the bacterial tubulin homologue FtsZ. We demonstrate that FtsZ-dependent cell elongation is possible, even in the absence of dedicated elongation machinery.


2000 ◽  
Vol 74 (23) ◽  
pp. 11027-11039 ◽  
Author(s):  
Eran Bacharach ◽  
Jason Gonsky ◽  
Kimona Alin ◽  
Marianna Orlova ◽  
Stephen P. Goff

ABSTRACT A yeast two-hybrid screen for cellular proteins that interact with the murine leukemia virus (MuLV) Gag protein resulted in the identification of nucleolin, a host protein known to function in ribosome assembly. The interacting fusions contained the carboxy-terminal 212 amino acids of nucleolin [Nuc(212)]. The nucleocapsid (NC) portion of Gag was necessary and sufficient to mediate the binding to Nuc(212). The interaction of Gag with Nuc(212) could be demonstrated in vitro and was manifested in vivo by the NC-dependent incorporation of Nuc(212) inside MuLV virions. Overexpression of Nuc(212), but not full-length nucleolin, potently and specifically blocked MuLV virion assembly and/or release. A mutant of MuLV, selected to specifically disrupt the binding to Nuc(212), was found to be severely defective for virion assembly. This mutant harbors a single point mutation in capsid (CA) adjacent to the CA-NC junction, suggesting a role for this region in Moloney MuLV assembly. These experiments demonstrate that selection for proteins that bind assembly domain(s) can yield potent inhibitors of virion assembly. These experiments also raise the possibility that a nucleolin-Gag interaction may be involved in virion assembly.


2016 ◽  
Vol 2 (10) ◽  
pp. e1501695 ◽  
Author(s):  
Ivan V. Smirnov ◽  
Andrey V. Golovin ◽  
Spyros D. Chatziefthimiou ◽  
Anastasiya V. Stepanova ◽  
Yingjie Peng ◽  
...  

In vitro selection of antibodies from large repertoires of immunoglobulin (Ig) combining sites using combinatorial libraries is a powerful tool, with great potential for generating in vivo scavengers for toxins. However, addition of a maturation function is necessary to enable these selected antibodies to more closely mimic the full mammalian immune response. We approached this goal using quantum mechanics/molecular mechanics (QM/MM) calculations to achieve maturation in silico. We preselected A17, an Ig template, from a naïve library for its ability to disarm a toxic pesticide related to organophosphorus nerve agents. Virtual screening of 167,538 robotically generated mutants identified an optimum single point mutation, which experimentally boosted wild-type Ig scavenger performance by 170-fold. We validated the QM/MM predictions via kinetic analysis and crystal structures of mutant apo-A17 and covalently modified Ig, thereby identifying the displacement of one water molecule by an arginine as delivering this catalysis.


2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Ngozi Awa Imaga

Sickle cell anemia is a genetically inherited disease in which the “SS” individual possesses an abnormal beta globin gene. A single base substitution in the gene encoding the humanβ-globin subunit results in replacement ofβ6 glutamic acid by valine, leading to the devastating clinical manifestations of sickle cell disease. This substitution causes drastic reduction in the solubility of sickle cell hemoglobin (HbS) when deoxygenated. Under these conditions, the HbS molecules polymerize to form long crystalline intracellular mass of fibers which are responsible for the deformation of the biconcave disc shaped erythrocyte into a sickle shape. First-line clinical management of sickle cell anemia include, use of hydroxyurea, folic acid, amino acids supplementation, penicillinprophylaxis, and antimalarial prophylaxis to manage the condition and blood transfusions to stabilize the patient's hemoglobin level. These are quite expensive and have attendant risk factors. However, a bright ray of hope involving research into antisickling properties of medicinal plants has been rewarding. This alternative therapy using phytomedicines has proven to not only reduce crisis but also reverse sickling (in vitro). The immense benefits of phytomedicines and nutraceuticals used in the management of sickle cell anemia are discussed in this paper.


1999 ◽  
Vol 19 (3) ◽  
pp. 1627-1639 ◽  
Author(s):  
Alexander M. Erkine ◽  
Serena F. Magrogan ◽  
Edward A. Sekinger ◽  
David S. Gross

ABSTRACT Previous work has shown that heat shock factor (HSF) plays a central role in remodeling the chromatin structure of the yeastHSP82 promoter via constitutive interactions with its high-affinity binding site, heat shock element 1 (HSE1). The HSF-HSE1 interaction is also critical for stimulating both basal (noninduced) and induced transcription. By contrast, the function of the adjacent, inducibly occupied HSE2 and -3 is unknown. In this study, we examined the consequences of mutations in HSE1, HSE2, and HSE3 on HSF binding and transactivation. We provide evidence that in vivo, HSF binds to these three sites cooperatively. This cooperativity is seen both before and after heat shock, is required for full inducibility, and can be recapitulated in vitro on both linear and supercoiled templates. Quantitative in vitro footprinting reveals that occupancy of HSE2 and -3 by Saccharomyces cerevisiae HSF (ScHSF) is enhanced ∼100-fold through cooperative interactions with the HSF-HSE1 complex. HSE1 point mutants, whose basal transcription is virtually abolished, are functionally compensated by cooperative interactions with HSE2 and -3 following heat shock, resulting in robust inducibility. Using a competition binding assay, we show that the affinity of recombinant HSF for the full-length HSP82promoter is reduced nearly an order of magnitude by a single-point mutation within HSE1, paralleling the effect of these mutations on noninduced transcript levels. We propose that the remodeled chromatin phenotype previously shown for HSE1 point mutants (and lost in HSE1 deletion mutants) stems from the retention of productive, cooperative interactions between HSF and its target binding sites.


Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3566-3566
Author(s):  
Myriam Salazar-Terreros ◽  
Kleber Yotsumoto Fertrin ◽  
Nicolas Moreno Reyes ◽  
Fernando Ferreira Costa ◽  
Carla F. Franco-Penteado

Mast cell function (MC) in pathologic states can be studied through their ability to secrete mediators in vitro depending on MC phenotype and the nature of the stimuli. Reports on MC mediators in sickle cell anemia (SCA) patients are scarce, but clinical signs of MC activation syndrome, such as increased plasma histamine in vaso‐occlusive crisis (VOC), and normal or slightly elevated serum tryptase have been reported. However, assessing the biological relevance of MC as a cytokine source is more challenging because it is unclear under which circumstances they secrete those products in vivo, or if the cytokines measured systemically stem from a different cell type. We aimed to investigate the profile of mediators involved in the inflammatory process produced by MC in SCA. Methods:The supernatant of 5-week old MC cultures (17 SCA, 8 HV) obtained from peripheral blood CD34+ cells from 29 SCA patients and 13 healthy volunteers (HV) was analyzed using a multiplex platform and colorimetric assays for endothelin-1 (ET-1) and substance P (SP) (10 SCA, 6 HV). A correlation matrix (Pearson correlations, R software, v. 3.6.1) was generated using laboratory and clinical data chosen based on their value as inflammatory or prognosis markers (hydroxyurea [HU] treatment, fetal hemoglobin [HbF], hemoglobin [Hb], vaso-occlusive crisis [VOC], percentage of peripheral blood neutrophils, eosinophils (Eos), basophils, erythroblasts, and reticulocytes), MC surface expression of CD117, CD48 and CD63, and the supernatant content of 11 cytokines. To investigate MC cytokine release, we tested the supernatants from Eos-MC co-cultures (3:1 ratio), and after stimulation with ET-1 (20 nM), SP (10 µM) and imatinib (20 µg/ml)(n=3 per treatment). Results: Out of 26 cytokines, we found elevated levels of the following in the supernatants of SCA-MC cultures (data represented as mean in pg/ml±SE): TNFα: SCA=88.7±18.4, HV=32.6±3.8; IFNγ: SCA=55.3±11.2, HV=15.7±1.8; MCP1: SCA=555.0±147.2, HV=145.3±35.2; RANTES: SCA=24.7±3.9, HV=10.7±1.8 (p<0.05). However, SCA-MC from patients treated with HU (n = 11) showed higher values of IL-1b, IL-4, IL-5, IL-9, IL-15, and FGF than HV (n=8) and HU-free patients (n=6) (p<0.05). Supernatants from SCA-MC had higher ET-1 production compared to HV-MC (SCA=16.3±1.2, HV=11.93±1.3, pg/ml, p=0.02) but SP production was similar (SCA=27.9±1.3; HV=31.49±0.7 pg/ml). ET-1 stimulation of MC cultures caused 2-fold increase in IL-1AR production on HV-MC, but failed to produce any effect on SCA-MC. Similarly, imatinib reduced FGF only in HV-MC samples (HV: 15.1±3.5, HV-HU: 4.0±1.6, pg/ml). No effect on cytokine production was observed with SP. Conversely, Eos-MC cocultures showed a 10- and 4-fold increase of IL-5 and IL-9, respectively, regardless of the origin of Eos (HV or SCA). SCA-MC/SCA-Eos co-cultures had elevated proinflammatory (IL-1b, IL-12, TNF-α) and angiogenic (FGF, VEGF) cytokines, RANTES, IL-7, IL-4, and IL1-RA compared with SCA-MC/HV-Eos and HV-MC/HV-Eos (p<0.05). Preliminary multiparametric analysis on data from SCA patients showed a strong negative correlation between HU therapy and VGEF production, and between HbF levels and CD63 expression (MC activation marker).We also found a positive correlation between history of VOC and eotaxin-1 produced by SCA-MC. Conclusions: We found that MC responses depend both on the origin of the cultured cell and the stimuli utilized. Despite differences between in vitro and in vivo MC populations, our data show that cultured SCA-MC have a sustained activated state and produce a repertoire of mediators that could contribute to a perivascular microenvironment in favor of leukocyte and endothelium activation. In terms of cytokine production, cultured SCA-MC were more sensitive to stimulation by SCA-Eos than by HV-Eos, which may be relevant to the pathophysiology of airway inflammation in SCA patients with asthma. Differences in cytokine production between SCA-MC cultures from patients treated or not with HU may reflect the variability in adherence to treatment, individual response to each compound, or epigenetic modifications during the MC differentiation process that affect the phenotype of the mature MC. These results support that mediators produced by MC can contribute to the chronic inflammatory state and may be implicated in exacerbated responses to eosinophil activation in SCA. Disclosures Fertrin: Agios Pharmaceuticals, Inc.: Research Funding.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 35-35
Author(s):  
Kelsey Temprine ◽  
Amanda Sankar ◽  
Costas Lyssiotis ◽  
Yatrik Shah

Background: Erythropoiesis is the highly coordinated multi-step process by which multipotent hematopoietic stem cells differentiate into mature enucleated red blood cells (RBCs). As erythroid cells become more terminally differentiated, they undergo changes in morphology and gene expression, start synthesizing hemoglobin, commit to an irreversible loss of proliferation, and eventually expulse their nuclei and other cytoplasmic organelles. Thus, RBCs must rely on their proteome and metabolome for proper function. The RBC proteome is estimated to contain 2,800 proteins, including a variety of receptors and transporters that allow RBCs to uptake xenobiotics or endogenous metabolites as they circulate for ∼120 days. Furthermore, they are metabolically active with glycolysis, nucleotide catabolism, and glutathione metabolism as the major pathways supporting cell survival and function. However, it is unclear how the metabolome is altered during erythropoiesis, what role metabolites play in normal erythropoiesis, and if dysregulation of metabolites contributes to diseases of ineffective erythropoiesis, such as sickle cell anemia and thalassemia. Methods: Four models of erythropoiesis were used in this study. 1) Mice were treated with phenylhydrazine (Phz) to induce acute hemolysis followed by erythropoietic recovery, leading to an increase in circulating reticulocytes. 2) Mice were lethally irradiated and transplanted with wild-type or sickle cell bone marrow, leading to anemic profiles in sickle cell chimeras. 3) The mouse erythroleukemic (MEL) cell line was treated with DMSO to induce differentiation. 4) The human erythroleukemic (K562) cell line was treated with sodium butyrate to induce differentiation. For the in vivo mouse models, blood was collected from control and treated animals, and complete blood count (CBC) analysis was performed. For the in vitro cell culture models, the mRNA levels of β-globin were measured by Q-RT-PCR in control and differentiated cells, and the degree of hemoglobinization was determined visually and via staining for heme. In addition, metabolites were extracted from the collected RBCs and erythroleukemic cell lines, and a Snapshot LC/MS metabolomic platform was used to identify commonly altered metabolites. Results: We first validated our four models of erythropoiesis. Treatment with Phz decreased the number of total RBCs while increasing the RBC distribution width, indicating an increased number of reticulocytes (more immature RBCs) in circulation. Similar results were seen in the sickle cell chimeras. Treatment of MEL and K562 cells with DMSO and sodium butyrate, respectively, resulted in increased expression of β-globin, increased levels of heme, and increased red color. Then, using our Snapshot metabolomic platform, we identified global changes in RBC metabolism during erythropoiesis. Analyses of the commonly altered metabolites in the in vitro and in vivo models revealed an increase in amino acid, mitochondrial, and urea cycle metabolism during erythropoiesis. L-aspartate levels were particularly upregulated, especially in DMSO-treated MEL cells. We are now investigating the role of aspartate in the regulation of erythropoiesis. Conclusions: We defined how the metabolome was altered in multiple in vitro and in vivo models of erythropoiesis and identified global changes in RBC metabolism between the different models. Specifically, we found that L-aspartate was upregulated during RBC differentiation in all four models. Aspartate is an amino acid that plays a role in many processes in cells, including nucleotide biosynthesis, redox homeostasis, and amino acid biosynthesis. We hypothesize that aspartate metabolism is critical for RBC differentiation and that its dysregulation exacerbates disease of ineffective erythropoiesis, such as sickle cell anemia and β-thalassemia. We are currently testing its role in inducing hemoglobinization and in regulating the commitment of erythroid progenitor cells to an irreversible loss of proliferation. Overall, we believe that understanding the precise mechanisms by which cellular metabolism plays a role in proper RBC differentiation may lead to better therapies for diseases of ineffective erythropoiesis, such as sickle cell anemia and thalassemia. Disclosures No relevant conflicts of interest to declare.


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