Hemoglobin Gene Research Articles

L-Glutamine and Crizanlizumab for Adults with Sickle Cell Disease (SCD) in Qatar: A Cost Effectiveness Analysis

Background :Sickle cell disease (SCD) is a hereditary disease that is caused by autosomal recessive gene fault in the beta (β) allele of the hemoglobin (Hb) gene. As a result, sickled cells are characterized by easy and abnormal hemolysis with resultant varying degrees of anemia. Globally, the incidence of SCD is estimated to reach 400,000 persons per year, and in the United States alone, for example, the prevalence estimation is approximately 100,000 patients. Possible clinical presentations of SCD may come from different pathophysiologic mechanisms: the disfiguration of the RBC with subsequent loss of function can lead to vascular occlusion and a short lifetime of these RBCs that leads to hemolysis. The most severe and serious manifestation of SCD is the recurrent acute pain, or better known as vaso-occlusive crisis (VOC). Additionally, other clinical manifestations that SCD patients may show are acute complications such as acute chest syndrome (ACS), recurrent infections, kidney necrosis, and stroke. Such complications may affect multiple organs and can result in early death. Acute pain crisis is another common complication of SCD and is usually managed with pain medications, especially opioids,This is the first study to address two of novel therapies in patients with SCD in the Middle East. Our study was comprehensive in terms of outcome mostly encountered by SCD patients which is VOC and inclusivity of interventions mostly used for its management and was focused on the target population of in one of areas of high prevalence of SCD in the world. Our analysis tracked the CHEERS guidelines and checklist for reporting. To be also complete, we used only RCT evidence in our analysis. Additionally, in considering VOC, we ensured only studies with a definition compatible with that of the principal Crizanlizumab study were analyzed.Objectives:Treatment options for preventing vaso-occlusive crises (VOC) among sickle cell disease (SCD) patients are on the rise, especially if hydroxyurea treatment has failed. This economic analysis is conducted to assess the comparative clinical effectiveness, safety and acquisition cost of L-glutamine and Crizanlizumab for older adolescent and adults (≥16 years old) SCD in Qatar, with an emphasis on treatment costs and acute pain crises.Methods:We conduct a decision tree model, where we compare the clinical and economic outcomes of two novel FDA-approved medications which are available in Qatar; L-glutamine and Crizanlizumab over a time horizon of one year in a hypothetical cohort of adult SCD patients from a Qatar healthcare perspective. The main outcome is incremental cost per SCD-related acute pain crises averted. Model clinical parameters were derived from individual drug randomized trials, published literature, whereas cost parameters from Qatar healthcare payer system. A sensitivity analysis was carried out, and the study results were robust around model inputs. Costs were converted to 2020 US dollars.Results:Study results showed that both treatment modalities' costs were the main driver of this analysis, with average annual cost of the treatments per patient being $189,014 for Crizanlizumab (5mg/Kg), $143,798 Crizanlizumab (2.5mg/Kg) and $74,323 for L-glutamine. The probability of no first time SCD-related VOC averted were 0.001/year for Glutamine, 0.26/year for Crizanlizumab (5mg/Kg) and 0.34/year for Crizanlizumab (2.5mg/Kg). Lower dose Crizanlizumab (2.5mg/Kg) dominated the higher one (5mg/Kg). The ICER of Crizanlizumab (2.5mg/Kg), when compared to L-Glutamine was $81,265 per SCD-related VOC averted. When comparing Crizanlizumab (5mg/Kg) and L-Glutamine, Crizanlizumab (5mg/Kg) showed higher efficacy, yet the Crizanlizumab ICER was at $459,620 than L-glutamine.Conclusions:Crizanlizumab (2.5mg/Kg) may be cost-effective interventions yet it is not the approved dose for preventing VOC in adolescents and adults with sickle cell disease. Crizanlizumab (5mg/Kg) was more cost effective than the approved L-glutamine per SCD vaso-occlusive crisis prevented. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

Higher Prevalence of Autoimmune Diseases in Patients with Sickle Cell Disease

IntroductionSickle cell disease (SCD) affects millions of people throughout the world. This is caused by a mutation in the hemoglobin gene resulting in abnormal red blood cells. Patients with SCD are in a state of chronic inflammation that is driven by ongoing hemolysis and ischemia-reperfusion injury due to recurrent vaso-occlusions.(1) It is also known that infections occur more frequently in patients with SCD. Abundant literature support the role of infections, interacting with the immune system as the so-called second hit in the cascade towards development of autoimmune diseases.(2) The chronic inflammation together with genetic predisposition and environmental factors can potentially lead to an auto-inflammatory state and/or disease. Recently, a study has shown a prevalence of autoimmune diseases (AID) of 1,3% in SCD patients between 7 and 17 years of age, although not compared to the general population.(3) Our hypothesis is that due to the chronic inflammation the prevalence of autoimmune diseases in adult patients with SCD are much higher compared to the general population. The aim of the study was to evaluate the proportion of patients with and without an AID.MethodsBetween 2004 and 2021, patients with SCD aged above 18 were seen at the outpatient clinic at the Amsterdam University Medical Center in Amsterdam. We performed a retrospective study in adult SCD patients to assess the prevalence of AID in SCD. AID was defined as: disease with the presence of autoantibodies and/or auto-reactive lymphocytes becoming involved in inflammation, which develop pathological autoimmunity and finally leads to tissue damage. We have selected 35 most common autoimmune diseases. A total of 338 patients with SCD were eligible and included in the study. The patient characteristics were summarized in Table 1. The previously reported prevalence of the AID in the African-American population was used to compare the prevalence in our study cohort. In addition, risk factors for AID and relation with organ damage was analyzed.ResultsAID was diagnosed in 36/338 patients with SCD. The prevalence of AID in this cohort is 10,7% compared to 4.7% in the general population (see table 2). There was no difference in patient characteristics (age, sex, genotype) between the SCD patients with or without AID. The BMI was higher in the group of patients with autoimmune diseases, although not statistically significant. In patients with SCD, the most frequent (>1%) diagnosed AID were: sudden deafness (1.8%), hyper- and hypothyroidism (3%) and sarcoidosis (1.2%). With respect to organ damage, a significantly high rate of retinopathy was observed in SCD patients with AID as compared to SCD patients without AID (53% and 29% respectively, p=0.005). Furthermore, a trend towards more frequently microalbuminuria was found in SCD patients with AID 14/36 (39%) as compared to patients without AID 69/302 (23%).ConclusionsThis study showed for the first time a higher prevalence of autoimmune diseases in adult patients with SCD compared to previous reported in the general population. In patients with AID, a trend towards more microalbuminuria and significantly higher rate of retinopathy were observed. These findings support the hypothesis that the chronic inflammatory state in SCD patients may be related to the development of AID. Further research is needed to find strategies to target the chronic inflammatory state in order to prevent the development of AID.

Interrogating Post-Transcriptional Mechanisms of Fetal Hemoglobin Regulation

Elevated levels of fetal hemoglobin (HbF) significantly ameliorate clinical outcomes for patients with beta-hemoglobinopathies, such as sickle cell disease (SCD). The only FDA-approved drug for treating SCD through inducing HbF is hydroxyurea, however the mechanism of action is unknown with variable effectiveness among patients. Thus, there remains a strong interest to identify more robust means of upregulating HbF, such as specific inhibition of HbF repressors. BCL11A and LRF are well-characterized transcription factors that independently repress the fetal type b-globin like genes HBG1 and HBG2 but their therapeutic potential is limited by challenging druggability and critical developmental function. However, upstream regulation of these factors, such as post-transcriptional mechanisms, are not well studied and may house novel therapeutic targets. To this end, we employed a CRISPR/Cas9 based screening approach to interrogate a library of RNA binding proteins (RBP) in the context of HbF regulation. Using HUDEP2 cells, a human adult-type erythroid progenitor cell line, we screened 341 human RBPs and identified four candidate RBPs, none of which have previously been implicated in HbF regulation. Of these candidates, RNA Binding Motif 12 (RBM12) showed the greatest level of HbF induction following in vitro depletion.Depletion of RBM12 protein in HUDEP2 cells and human CD34 + hematopoietic stem and progenitor cells (HSPC) via CRISPR/Cas9 editing raised HbF production 2-4 fold as assessed by HbF flow cytometry, HBG1/2 mRNA, and protein (γ-globin). Cell viability and maturation of RBM12 perturbed cells were largely intact. Additionally, RBM12 depletion in CD34 + HSPCs derived from SCD patients resulted in reduced percentage of sickled cells under hypoxic conditions. Unexpectedly, reduction of RBM12 had minimal effect on BCL11A and LRF expression suggesting that RBM12 may regulate HbF through a pathway that is indirectly related or independent of these transcription factors.RBM12 is an RBP that is widely expressed across diverse cell types and contains multiple RNA recognition motifs (RRM). While it has been implicated in various cancers and neurological disorders, its functions are not well studied. As an RBP, RBM12 can carry out several roles of post-transcriptional regulation, such as pre-mRNA splicing, mRNA transport, stabilization, and translation. As these activities are executed in different cellular compartments, we set out to narrow down RBM12 function by assessing its subcellular localization. Immunofluorescence staining revealed strong nuclear presence of RBM12, suggesting that it functions via mRNA biogenesis and/or processing. RNASeq and LC-MS/MS analysis of RBM12 KO CD34 + HSPCs revealed modest changes in the transcriptome and proteome. In order to gain mechanistic insight into RBM12 in the context of HbF regulation, we performed cDNA rescue experiments in RBM12-deficient HUDEP2 clones. Overexpression of full length RBM12 restored HbF repression. Notably, four out of the five RRMs were dispensable for HbF silencing, but RRM1 was essential for this activity. Interestingly, an extended form of RRM1 was also sufficient for HbF silencing. Mechanistic studies of this RRM1 module are underway and will be discussed.In sum, the identification of RBM12 as a regulator of HbF production represents a previously undescribed post-transcriptional layer of hemoglobin gene regulation. In pursuing this path, we hope to gain a deeper understanding of this understudied RBP in the context of HbF regulation which might in turn lead to the identification of potential therapeutic targets for the treatment of SCD and other hemoglobinopathies. DisclosuresBlobel: Pfizer: Consultancy; Fulcrum Therapeutics, Inc.: Consultancy.

Vitreoscilla Hemoglobin Improves Sophorolipid Production in Starmerella Bombicola O-13-1 Under Oxygen Limited Conditions.

Sophorolipids (SLs) are homologous microbial secondary metabolites produced by Starmerella bombicola and have been widely applied in many industrial fields. The biosynthesis of SLs is a highly aerobic process and is often limited by low dissolved oxygen (DO) levels. In this study, the Vitreoscilla hemoglobin (VHb) gene was transformed into S. bombicola O-13–1 by homologous recombination to alleviate oxygen limitation. VHb expression improved the intracellular oxygen utilization efficiency under either oxygen-rich or oxygen-limited conditions. In shake flask culture, the production of SLs was higher in the recombinant (VHb+) strain than in the wild-type (VHb−) strain, while the oxygen uptake rate of the recombinant (VHb+) strain was significantly lower than that of the wild-type (VHb−) strain. In a 5 L bioreactor, the production of SLs did not increase significantly, but the DO level in the fermentation broth of the VHb+ strain was 21.8% higher than that of VHb− strain under oxygen-rich conditions. Compared to wide-type strains (VHb−), VHb expression enhanced SLs production by 25.1% in the recombinants (VHb+) under oxygen-limited conditions. In addition, VHb expression raised the transcription levels of key genes involved in the electron transfer chain (NDH, SDH, COX), TCA cycle (CS, ICD, KDG1) and SL synthesis (CYP52M1 and UGTA1) in the recombinant (VHb+) strains. VHb expression in S. bombicola could enhance SLs biosynthesis and intracellular oxygen utilization efficiency by increasing ATP production and cellular respiration. Our findings highlight the potential use of VHb to improve the oxygen utilization efficiency of S. bombicola in the industrial-scale production of SLs using industrial and agricultural by-products like molasses and waste oil as fermentation feedstock.

Generational sensitivity alteration in Chironomus yoshimatsui to carbamate and pharmaceutical chemicals and the effect on Catalase, CYP450, and hemoglobin gene transcription.

To ascertain the tolerance mechanisms of aquatic organisms to artificial chemicals, intergenerational sensitivity changes of Chironomus yoshimatsui to a carbamate pesticide (pirimicarb) and pharmaceutical chemical (diazepam) were investigated. The larvae (<48-h-old) in each generation were exposed to both chemicals for 48 h and then the surviving chironomids were cultured until the fifth generation (F0-F4) without chemical addition. The 48-h 50% effective concentration (EC50) value of chironomids was determined for each generation. In the pirimicarb treatment group, the EC50 values significantly increased in F3 and F4, and those in the diazepam treatment group slightly increased. Catalase, Cytochrome P450 and hemoglobin (Hb) mRNA levels were monitored to see whether these were related to the trans-generational sensitivity. Although the generalized linear model results showed that the sensitivity to diazepam was slightly increased in the diazepam treatment, we could not find any mRNA levels related to sensitivity alteration. In contrast, the model approach showed that the chironomids exposed to pirimicarb trans-generationally became tolerant with increasing Hb mRNA levels. Therefore, they might decrease their chemical stress by modifying Hb gene transcription.

Coexpression of VHb and MceG genes in Mycobacterium sp. Strain LZ2 enhances androstenone production via immobilized repeated batch fermentation

Androstenone production is limited by low-efficiency substrate transport and dissolved oxygen levels during fermentation. In this study, the coexpression of the optimized Vitreoscilla hemoglobin (VHb) and sterol transporter ATPase (MceG) genes in Mycobacterium sp. LZ2 (Msp) was investigated to alleviate dissolved oxygen and mass transfer limitations. Results revealed that Msp-vgb/mceG effectively improved the growth, production, and adaptation to dissolved oxygen compared with those of Msp. The increased catalase activity and reduced intracellular ROS levels enhanced cell viability and promoted transcription of genes critical for phytosterol metabolism. Bagasse as an immobilization carrier increased the productivity of Msp-vgb/mceG by 56%. Immobilized repeat batch fermentation reduced the biotransformation period from 60 days to 37 days and improved the productivity from 0.039 g/L/h to 0.069 g/L/h. To the best of our knowledge, this work is the first study on the immobilization of recombinant mycobacteria on bagasse for androstenone production.

The TVGH-NYCU Thal-Classifier: Development of a Machine-Learning Classifier for Differentiating Thalassemia and Non-Thalassemia Patients.

Thalassemia and iron deficiency are the most common etiologies for microcytic anemia and there are indices discriminating both from common laboratory simple automatic counters. In this study a new classifier for discriminating thalassemia and non-thalassemia microcytic anemia was generated via combination of exciting indices with machine-learning techniques. A total of 350 Taiwanese adult patients whose anemia diagnosis, complete blood cell counts, and hemoglobin gene profiles were retrospectively reviewed. Thirteen prior established indices were applied to current cohort and the sensitivity, specificity, positive and negative predictive values were calculated. A support vector machine (SVM) with Monte-Carlo cross-validation procedure was adopted to generate the classifier. The performance of our classifier was compared with original indices by calculating the average classification error rate and area under the curve (AUC) for the sampled datasets. The performance of this SVM model showed average AUC of 0.76 and average error rate of 0.26, which surpassed all other indices. In conclusion, we developed a convenient tool for primary-care physicians when deferential diagnosis contains thalassemia for the Taiwanese adult population. This approach needs to be validated in other studies or bigger database.

Expression of the Vitreoscilla hemoglobin gene in Nannochloropsis oceanica regulates intracellular oxygen balance under high-light.

Nannochloropsis oceanica is widely used as a model photosynthetic chassis to produce fatty acids and carotenoid pigments. However, intense light typically causes excessive generation of reactive oxygen species (ROS) and photorespiration in microalgal cells, which results in decreased cell growth rate and unsaturated fatty acid content. In this study, the Vitreoscilla hemoglobin gene (vgb) was introduced into N. oceanica cells and expressed by using the light-harvesting complex promoter and its signal peptide. Compared with wild type (WT), the growth rate of transformants increased by 7.4%-18.5%, and the eicosapentaenoic acid content in an optimal transformant increased by 21.0%. Correspondingly, the intracellular ROS levels decreased by 56.9%-70.0%, and the catalase content in transformants was about 1.8 times that of WT. The photorespiration level of transformants was reduced by the measurement and calculation of the dissolved oxygen concentration under the condition of light-dark transition. The expression level of the key genes related to the photorespiration pathway in transformants was more than 80% lower than that in WT. These results indicated that Vitreoscilla hemoglobin could improve microalgal growth by reducing ROS damage and modulating photorespiration under stress conditions.

Analysis of clinical presentation, hematological factors, self-reported bed net usage, and malaria burden in sickle cell disease patients.

BackgroundSickle cell anemia (SCA) is a severe monogenic disorder, caused by single nucleotide mutations in the hemoglobin (Hb) gene, that is prevalent in malaria endemic regions of the world. Sickle cell trait (SCT) individuals carry only one of the mutated alleles and were shown to be protected against malaria. However, defining the relative contribution of hematological, clinical, and environmental factors to the overall burden of malaria in individuals with hemoglobinopathies such as SCA has been challenging.MethodsWe hypothesized that hematological differences, clinical presentations, and self-reported bed net usage among Plasmodium-infected and uninfected individuals may govern overall malaria burden in individuals with sickle cell disease (SCD). We conducted a cross-sectional study in Ghana from 2014 to 2019 and described clinical presentations, hematological characteristics, and bed net use based on a comprehensive questionnaire. Hematological characteristics were compared using a parametric or nonparametric ANOVA, pending if data passed D'Agostino & Pearson normality test. When comparing only two Hb genotypes hematological characteristics a Mann–Whitney U-test were used. Logistic regressions and Chi-squared tests were used to compare questionnaire responses between Hb genotypes. All statistical significance was set at p < 0.05.FindingsMultiple hematological parameters were significantly (p < 0.05) altered depending on sickle cell genotype and/or malaria status. When compared to other Hb genotypes, SCA individuals with or without malaria had significantly (p < 0.05) higher WBC and platelets counts and lower Hb levels. While the sickle cell genotype may affect malaria severity, SCT and SCA participants were found to significantly (p < 0.007) use bet nets more than HbAA participants.InterpretationsOur findings can be utilized to enhance national guidelines for reducing the incidence of malaria especially among individuals with SCD, SCT protection and health disparities among hemoglobinopathies.FundingThis study was supported by the National Institute for Health.

Effects of Efficient Expression of Vitreoscilla Hemoglobin on Production, Monosaccharide Composition, and Antioxidant Activity of Exopolysaccharides in Ganoderma lucidum.

A Vitreoscilla hemoglobin (VHb) gene was efficiently expressed by the optimization of codons and intron addition in G. lucidum. Expression of the VHb gene was confirmed by genome PCR, quantitative real-time PCR and carbon monoxide (CO)-difference spectrum analysis in the transformant. The effects of the efficient expression of VHb gene on production, monosaccharide compostion, and antioxidant activity of G. lucidum exopolysaccharides were studied. The maximum production of exopolysaccharides in the VHb gene-bearing transformant was 1.63 g/L, which was 1.5-fold higher than expression in the wild-type strain. Efficient expression of the VHb gene did not change the monosaccharide composition or distribution of molecular weight, but it increased the mole percentage ratio of galactose and mannose in G. lucidum exopolysaccharide. Exopolysaccharides from the transformant had higher scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl (OH) radical capacity and reducing power than those from the wild-type strain. These results may be helpful for increasing production and application of exopolysaccharides produced by G. lucidum fermentation.

Chromosome-level genome assembly of Scapharcakagoshimensis reveals the expanded molecular basis of heme biosynthesis in ark shells.

Ark shells are commercially important clam species that inhabit in muddy sediments of shallow coasts in East Asia. For a long time, the lack of genome resources has hindered scientific research of ark shells. Here, we report a high-quality chromosome-level genome assembly of Scapharca kagoshimensis, with an aim to unravel the molecular basis of heme biosynthesis, and develop genomic resources for genetic breeding and population genetics in ark shells. Nineteen scaffolds corresponding to 19 chromosomes were constructed from 938 contigs (contig N50=2.01Mb) to produce a final high-quality assembly with a total length of 1.11Gb and scaffold N50 around 60.64Mb. The genome assembly represents 93.4% completeness via matching 303 eukaryota core conserved genes. A total of 24,908 protein-coding genes were predicted and 24,551genes (98.56%) of which were functionally annotated. The enrichment analyses suggested that genes in heme biosynthesis pathways were expanded and positive selection of the haemoglobin genes was also found in the genome of S.kagoshimensis, which gives important insights into the molecular mechanisms and evolution of the heme biosynthesis in mollusca. The valuable genome assembly of S.kagoshimensis would provide a solid foundation for investigating the molecular mechanisms that underlie the diverse biological functions and evolutionary adaptations of S.kagoshimensis.

Insights into Hematopoiesis in GATA2 Deficiency Using Single-Cell Transcriptomics

GATA2 is an essential transcription factor in hematopoiesis. Germline GATA2 mutations have been identified as the cause of familial syndromes with immunodeficiency and predisposition to myeloid malignancies. GATA2 deficiency results in varying clinical outcomes manifesting at either young or older age. Reason for the variation of the disease phenotype preceding hematological malignancy is not known. GATA2 mutations appear to cause loss of function of the mutated allele resulting in haploinsufficiency. Several different types of mutations in GATA2 have been identified; truncating, missense, large deletions, and regulatory region mutations. The most direct GATA2 control pathway is the effect it has on hematopoietic stem cells (HSCs). Through the progeny of the hematopoietic stem cells that function under GATA2 control, GATA2 indirectly has a great effect on immune system, both protection against external infection and internal tumor formation. We aimed at deciphering how do GATA2-mutated cells differ from wild type (wt) and what are the differences between GATA2 wt vs. GATA2-mutated cells' progeny and downstream signaling? One of the genes positively regulated by GATA2 is NFE2 . NFE2 encodes a component of the NF-E2 complex essential for regulating erythroid and megakaryocytic maturation and differentiation. As GATA2-positive cells are scarce in PB we focused in our analyses on NFE2-positive cells.We conducted single-cell transcriptomic analysis using 10x Genomics Chromium Single Cell 3′ Solution (Zheng et al . Nature Communications, 2017) on peripheral blood (PB) samples from five GATA2 mutation carriers and two healthy controls. The studied GATA2 variants were p.Q328X (two cases), p.T354M, p.G237D, and a sample where a GATA2 mutation has not been identified, but only one allele GATA2 is expressed i.e. haploinsufficiency. Erythrocytes were lysed prior to washing, filtering and diluting the white blood cells in suitable concentration (1x106 cells/mL) for the analysis. The gel beads in emulsion (GEM) generation was performed using the Chromium Single Cell 3‘ v2 Reagent Kit (10x Genomics) aiming for a 3000-cell capture per sample. The Illumina ready sequencing libraries were prepared according to the 10x Genomics instructions and the sample libraries were sequenced in Illumina HiSeq 2500 using Rapid mode. The Cell Ranger v1.3 analysis pipelines (10x Genomics) were used to demultiplex and convert Chromium single cell 3‘ RNA-sequencing barcode and read data to FASTQ files and to generate align reads and gene-cell matrices.Significant gene expression differences in NFE2 expressing cells between patients carrying different variants in GATA2 were observed. Intriguingly, significant expression changes were noted e.g. in CD74, CFD, CTSS, CLEC1B, and CMTM5, all linked to cell signaling and immunological responses. Comparison of GATA2 -mutated vs. controls in NFE2 expressing cells revealed significant changes in expression patterns in hemoglobin genes HBA1, HBA2, and HBB, as well as in e.g. other erythrocyte-associated genes ALAS2 and AHSP. Further analyses also revealed significantly distinct expression patterns in PB eosinophils between study patients and controls in e.g. CEBPD, VCAN, and RGS2 . Also, when comparing the eosinophils from individual patients with controls and each other, we identified distinct expression patterns in e.g. CAMP, and NKG7, which play important roles in the immune system.Following germline GATA2 mutation discovery in acute myeloid leukemia / myelodysplastic syndrome / immunodeficiency patients, we conducted whole transcriptome analysis to decipher the GATA germline mutation defects on single-cell level. Single-cell transcriptomics enables analyzing the role of e.g. GATA2 in a selected cell type and its' progeny. Phenotype of GATA2-deficient patients is multi-faced but generally manifested by challenges in immune functions and autoinflammation. Connection between our findings and patients' clinical manifestations is interesting and triggers us to investigate the possible link further. We will furthermore study the bone marrow sample single-cell transcriptomes to deepen the understanding of GATA2 deficiency on stem cell level and validate our transcriptome analysis findings. All this will hopefully increase our understanding on GATA2 deficiency disease mechanisms and improve patient (family) care. DisclosuresNo relevant conflicts of interest to declare.

Association of Sickle Cell Trait with Risk and Mortality of COVID-19: Results from the United Kingdom Biobank

ABSTRACT.Sickle cell trait (SCT) carriers inherit one copy of the Glu6Val mutation in the hemoglobin gene and is particularly common in Black individuals (5–10%). Considering the roles of hemoglobin in immune responses and the higher risk for coronavirus disease (COVID-19) among Black individuals, we tested whether Black SCT carriers were at increased risk for COVID-19 infection and mortality according to the United Kingdom Biobank. Among Black individuals who were tested for COVID-19, we found similar infection rates among SCT carriers (14/72; 19.7%) and noncarriers (167/791; 21.1%), but higher COVID-19 mortality rates among SCT carriers (4/14; 28.6%) than among noncarriers (21/167; 12.6%) (odds ratio [OR], 3.04; 95% confidence interval [CI], 0.69–11.82; P = 0.12). Notably, SCT carriers with preexisting diabetes had significantly higher COVID-19 mortality (4/4; 100%) than those without diabetes (0/10; 0%; (OR, 90.71; 95% CI, 5.66–infinite; P = 0.0005). These findings suggest that Black SCT carriers with preexisting diabetes are at disproportionally higher risk for COVID-19 mortality. Confirmation by larger studies is warranted.

Association of Sickle Cell Trait on Career and Operational Outcomes in the United States Air Force.

Sickle cell trait (SCT) is a heterozygotic state defined by having one normal hemoglobin gene and one sickle hemoglobin gene. Individuals with SCT are at increased risk for negative health outcomes during intense physical exertion, especially in hot climates and high-elevation locations, or when dehydrated. The U.S. Air Force mitigates this risk through universal screening after accession followed by education of SCT-positive airmen. Airmen who are SCT positive but remain asymptomatic are not restricted in occupation choice or deployment/duty locations based on their SCT status. Previous studies have analyzed the relationship between SCT and health and fitness outcomes. The objective of this study was to analyze the relationship between SCT and career and operational outcomes in a large cohort of airmen and secondarily to analyze the relationship between hemoglobin S (HgbS) percentage and these outcomes. This is a retrospective cohort study of all recruits who entered U.S. Air Force (USAF) Basic Military Training (BMT) between January 2009 and December 2013. The SCT status was assessed through a sickle solubility test. Hemoglobin electrophoresis permitted subgroup analysis of SCT-positive individuals by HgbS percentage. The following career and operational outcomes were assessed: BMT graduation; retention at 4 and 6 years; promotion to the rank of staff sergeant by 4 and 6 years; overseas deployment and number of deployments within 6 years; and high-elevation assignment and cumulative months at a high-elevation assignment within 6 years. Multivariable logistic regression was used to assess all binary outcomes, controlling for age, sex, and race, to produce adjusted odds ratios (aORs) with 95% confidence intervals (CIs). Multivariable Poisson regression was used to assess cumulative count outcomes and to produce adjusted incidence rate ratios (aIRRs) with 95% CIs. Attrition from BMT by SCT status was also assessed as a hazards function using the Kaplan-Meier approach with Cox proportional hazards. A total of 180,355 civilians entered USAF BMT during the 5-year surveillance period, of whom 169,837 graduated and had data available for analysis. Compared to their SCT-negative peers, SCT-positive airmen (n = 1,697) had 26% lower adjusted odds of promotion to staff sergeant within 4 years of BMT graduation (aOR = 0.74; 95% CI: 0.59-0.92) and served less time at a high-elevation assignment during their first 6 years (aIRR = 0.88; 95% CI: 0.85-0.91). The SCT status was not associated with statistically significant differences in BMT graduation, retention at 4 and 6 years, promotion to staff sergeant by 6 years, likelihood or number of overseas deployments, and likelihood of ever working at a high-elevation assignment. Retention at 4 and 6 years was inversely associated with HgbS percentage. SCT-positive and SCT-negative airmen had similar career and operational outcomes, with two exceptions: SCT-positive airmen were less likely to be promoted to staff sergeant within 4 years, and they spent less time at a high-elevation location during their first 6 years of service. The underlying explanation of these findings should be explored with an aim to support SCT-positive airmen and to reduce potentially unwarranted discrepancies. Efforts should continue to reduce the stigma associated with SCT.

A chromosome level genome assembly of Propsilocerus akamusi to understand its response to heavy metal exposure.

Chironomidae species are universally used for studying the impact of pollutants in aquatic systems. The nonbiting midge Propsilocerus akamusi is often found in urban streams and is suitable for use as a toxicological bioindicator. However, few studies have previously examined metal stress in this species. We sequenced the genome of this urban midge to address this question. Here, we present the first chromosome-level genome of P.akamusi, obtained from Illumina short-read and PacBio long-read sequences with Hi-C technology. The size of the very small assembled genome was 85.83Mb with a contig N50 of 6.2Mb and a scaffold N50 of 26.1Mb. This assembly revealed significant expansion of haemoglobin (Hb) genes, some of which formed large tandem repeats. Transcriptomic studies for copper tolerance identified four genes in the tandem array that were highly expressed, all of which presented intron loss. This characteristic might highlight the potential role of Hb genes in copper tolerance. Additionally, detoxification genes, chemosensory genes and heat shock protein genes of this midge were identified, some of which are associated with metal stress. The high-quality assembled genome of P.akamusi and the transcriptomic analyses provide new insight into the molecular mechanisms of heavy metal stress. Our comparison of the P.akamusi genome with other dipteran genomes provides valuable resources for understanding the evolutionary history, genetics, and ecology of this species as well as those of other midges.

Expression of soybean plant hemoglobin gene family under abiotic stresses

Many abiotic stresses induce the generation of nitric oxide (NO) in plant tissues, where it functions as a signal molecule in stress responses. Plants modulate NO by oxidizing it to NO3 - with plant hemoglobin (GLB), because excess NO is toxic to cells. At least eight genes encoding GLB have been identified in soybean, in three clades: GLB1, GLB2, and GLB3. However, it is still unclear which GLB genes are responsible for NO regulation under abiotic stress in soybean. We exposed soybean roots to flooding, salt, and two NO donors-sodium pentacyanonitrosylferrate (III) dihydrate (SNP) and S-nitroso-N-acetyl-d,l-penicillamine (SNAP)-and analyzed expression of GLB genes. GmGLB1, one of two GLB1 genes of soybean, significantly responded to both SNP and SNAP, and its induction was almost completely repressed by a NO scavenger, 2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide. GmGLB1 responded to flooding but not to salt, suggesting that it is responsible for NO regulation under NO-inducing abiotic stresses such as flooding. GmGLB3, one of two GLB3 genes of soybean, did not respond to NO donors at all but did respond to flooding, at a lower level than GmGLB1. These results suggest that flooding induces not only NO but also unknown factor(s) that induce GmGLB3 gene in soybean.

Pathophysiology of Sickle Cell Anemia : Review Article

About 5–7% of the world population have an unhealthy hemoglobin (Hb) gene . The most common form ofhemoglobinopathy globally is sickle cell disease. Sickle cell disorder (SCD) is the major predominant innateclutter of Hb amalgamation stamped through a change within the ? globin gene, which result within thesubstitution of glutamate corrosive with valine at the 6th codon and union of Hb S a which is a hemoglobin,beneath hypoxic states, coming about within the abnormality of RBCs (Red Blood Corpuscles). The lysis oferythrocytes result in raise in extracellular hemoglobin, hence hoisting liking and official to open nitric oxideor antecedents of nitric oxide in this manner diminishing its levels and assist partaking to vasoconstriction .Sickle ruddy blood cells since of their hardness to stream by means of the micro-circulation, results in visitvaso-occlusive scenes, destitute micro-vascular blood stream, ischemic damage, and myocardial localizednecrosis . The clinical highlights of sickle cell anemia are constant hemolytic weakness, an elevatedvulnerability to diseases, repetitive difficult Vaso-Occlusive Emergency (VOC) and a brought down lifehope .

RNA-Seq analysis of knocking out the neuroprotective proton-sensitive GPR68 on basal and acute ischemia-induced transcriptome changes and signaling in mouse brain.

Brain acid signaling plays important roles in both physiological and disease conditions. One key neuronal metabotropic proton receptor in the brain is GPR68, which contributes to hippocampal long-term potentiation (LTP) and mediates neuroprotection in acidotic and ischemic conditions. Here, to gain greater understanding of GPR68 function in the brain, we performed mRNA-Seq analysis in mice. First, we studied sham-operated animals to determine baseline expression. Compared to wild type (WT), GPR68-/- (KO) brain downregulated genes that are enriched in Gene Ontology (GO) terms of misfolding protein binding, response to organic cyclic compounds, and endoplasmic reticulum chaperone complex. Next, we examined the expression profile following transient middle cerebral artery occlusion (tMCAO). tMCAO-upregulated genes cluster to cytokine/chemokine-related functions and immune responses, while tMCAO-downregulated genes cluster to channel activities and synaptic signaling. For proton-sensitive receptors, tMCAO downregulated ASIC1a and upregulated GPR4 and GPR65, but had no effect on ASIC2, PAC, or GPR68. GPR68 deletion did not alter the expression of these proton receptors, either at baseline or after ischemia. Lastly, we performed GeneVenn analysis of differential genes at baseline and post-tMCAO. Ischemia upregulated the expression of three hemoglobin genes, along with H2-Aa, Ppbp, Siglece, and Tagln, in WT but not in KO. Immunostaining showed that tMCAO-induced hemoglobin localized to neurons. Western blot analysis further showed that hemoglobin induction is GPR68-dependent. Together, these data suggest that GPR68 deletion at baseline disrupts chaperone functions and cellular signaling responses and imply a contribution of hemoglobin-mediated antioxidant mechanism to GPR68-dependent neuroprotection in ischemia.

Unusually Fast bis-Histidyl Coordination in a Plant Hemoglobin.

The recently identified nonsymbiotic hemoglobin gene MtGlb1-2 of the legume Medicago truncatula possesses unique properties as it generates four alternative splice forms encoding proteins with one or two heme domains. Here we investigate the ligand binding kinetics of MtGlb1-2.1 and MtGlb1-2.4, bearing two hemes and one heme, respectively. Unexpectedly, the overall time-course of ligand rebinding was unusually fast. Thus, we complemented nanosecond laser flash photolysis kinetics with data collected with a hybrid femtosecond–nanosecond pump–probe setup. Most photodissociated ligands are rebound geminately within a few nanoseconds, which leads to rates of the bimolecular rebinding to pentacoordinate species in the 108 M−1s−1 range. Binding of the distal histidine to the heme competes with CO rebinding with extremely high rates (kh ~ 105 s−1). Histidine dissociation from the heme occurs with comparable rates, thus resulting in moderate equilibrium binding constants (KH ~ 1). The rate constants for ligation and deligation of distal histidine to the heme are the highest reported for any plant or vertebrate globin. The combination of microscopic rates results in unusually high overall ligand binding rate constants, a fact that contributes to explaining at the mechanistic level the extremely high reactivity of these proteins toward the physiological ligands oxygen, nitric oxide and nitrite.

Persistence of CRISPR/Cas9 gene edited hematopoietic stemcells following transplantation: A systematic review andmeta-analysis of preclinical studies.

Gene editing blood‐derived cells is an attractive approach to cure selected monogenic diseases but remains experimental. A systematic search of preclinical controlled studies is needed to determine the persistence of edited cells following reinfusion. All studies identified in our systematic search (to 20 October 2020) examining the use of CRISPR/Cas9 gene editing in blood‐derived cells for transplantation were included. Meta‐analysis was performed to determine the engraftment and persistence of gene edited cells. A total of 3538 preclinical studies were identified with 15 published articles meeting eligibility for meta‐analysis. These in vivo animal studies examined editing of hemoglobin to correct sickle cell disease (eight studies), inducing resistance to acquired immunodeficiency syndrome (two studies), and six other monogenic disorders (single studies). CRISPR‐Cas9 edited hematopoietic stem and progenitor cells demonstrated equivalent early engraftment compared to controls in meta‐analysis but persistence of gene‐edited cells was reduced at later time points and in secondary transplant recipients. Subgroup analysis in studies targeting the hemoglobin gene revealed a significant reduction in the persistence of gene‐edited cells whether homology‐directed repair or nonhomologous end‐joining were used. No adverse side effects were reported. Significant heterogeneity in study design and outcome reporting was observed and the potential for bias was identified in all studies. CRISPR‐Cas9 gene edited cells engraft similarly to unedited hematopoietic cells. Persistence of gene edited cells, however, remains a challenge and improved methods of targeting hematopoietic stem cells are needed. Reducing heterogeneity and potential risk of bias will hasten the development of informative clinical trials.