Glucose-6-phosphate Dehydrogenase Activity Research Articles

Molecular epidemiological characteristics, variant spectrum and genotype-phenotype correlation of glucose-6-phosphate dehydrogenase deficiency in China: A population-based multicenter study using newborn screening.

Newborn screening (NBS) for glucose-6-phosphate dehydrogenase (G6PD) deficiency by biochemical tests is being used worldwide, however, the outcomes arising from combined genetic and biochemical tests have not been evaluated. This research aimed to evaluate the outcomes of application of combined genetic and biochemical NBS for G6PD deficiency and to investigate the molecular epidemiological characteristics, variant spectrum, and genotype-phenotype correlation of G6PD deficiency in China. A population-based cohort of 29,601 newborns were prospectively recruited from eight NBS centers in China between February 21 and December 30, 2021. Biochemical and genetic NBS was conducted simultaneously. The overall prevalence of G6PD deficiency was 1.12% (1.86% for male, and 0.33% for female; 1.94% for South China and 0.08% for North China). Genetic NBS identified 10 male patients undetected by biochemical NBS. The overall positive predictive values (PPVs) of biochemical and genetic NBS were 79.95% and 47.57%, respectively. A total of 15 variants were identified, with the six most common variants being c.1388G > A, c.1376G > T, c.95A > G, c.871G > A, c.1024C > T and c.392G > T (94.2%). The activity of G6PD was correlated with the type and WHO classification of variants. This study highlighted that combined screening could enhance the efficiency of current NBS for diagnosing G6PD deficiency. The prevalence, variant spectrum and allele frequency of G6PD deficiency vary across different regions. Our data provide valuable references for clinical practice and optimization of future screening strategies for G6PD deficiency.

Buffy coat removal to mitigate reporting false normal G6PD phenotype results in patients undergoing rasburicase therapy for tumor lysis syndrome

Abstract Glucose-6-phosphate dehydrogenase (G6PD) is the primary source of NADPH in red blood cells (RBCs). NADPH reduces reactive oxygen species (ROS) thereby protecting RBCs from oxidative stress-mediated hemolytic anemia (HA). Individuals with partial or full G6PD deficiency are therefore susceptible to acute HA provoked by medications that generate high ROS loads in vivo, e.g., rasburicase. Rasburicase is an enzyme-based therapeutic used to degrade uric acid (UA) in patients with tumor lysis syndrome (TLS); however, catalysis of UA generates H2O2, a potent ROS, which poses a risk of HA in individuals who are deficient in G6PD activity. Screening G6PD activity prior to rasburicase administration is clinically indicated in ethnic groups with high rates of G6PD deficiency, although reports of HA in rasburicase-treated patients have been reported across low prevalence ethnic groups as well. TLS occurs most commonly during the treatment of highly proliferative neoplasms, such as leukemia and lymphoma. Since WBCs contain significant G6PD activity, an elevated WBC count in these patients can cause the false assurance of low HA risk due to a falsely normal G6PD activity. We sought to establish and evaluate a novel method to mitigate WBC contamination of G6PD measurements in patients undergoing rasburicase therapy. In this study, we first developed and validated an innovative method (“piercing method”) to minimize the interference of WBCs in G6PD measurements. The piercing method demonstrated acceptable accuracy (slope: 1.008; bias: -6.22%) and precision (1.4% CV between 9.9 to 20.7 U/g Hb) and was effective at eliminating a broad range of WBC types and concentrations from whole blood samples (N = 85, tested range = 0.31 – 413.05 K/μL, 93% reduction in WBCs). We compared G6PD activity in rasburicase-treated patients (N = 39) with varying WBC counts before and after buffy coat removal using the piercing method. Average percent change in G6PD activity (post-pierce – pre-pierce) between patients with and without elevated WBCs was substantial (45% versus 12%). In comparing G6PD activity in patients before and after the initiation of rasburicase therapy, there is no evidence that in vivo-generated ROS from rasburicase affect G6PD measurement in vitro in an assay that relies on monitoring absorbance of NADPH (22.2 U/g Hb versus 22.9 U/g Hb, p=0.721). Results demonstrate how WBCs increase risk for false elevation in G6PD activity in patients being considered for rasburicase therapy. At greatest risk are patients with partial G6PD deficiency, e.g., heterozygous females, where G6PD from WBCs could mask deficiency. Literature describing testing of G6PD in specimens with elevated WBCs is lacking. This study shows that the piercing method provides accurate G6PD results in samples with elevated WBCs from patients at risk of TLS, who might develop HA after starting rasburicase therapy.

Change in Activities of Enzymes of Energy and Carbohydrate Metabolism in Pink Salmon Oncorhynchus gorbuscha (Walb.) Smolts with Change in Environmental Salinity.

Activities of key enzymes of energy and carbohydrate metabolism (cytochrome c oxidase (COX), lactate dehydrogenase (LDH), aldolase, glucose 6-phosphate dehydrogenase (G6PDH), and 1-glycerophosphate dehydrogenase (1-GPDH)) were studied in pink salmon Oncorhynchus gorbuscha (Walb.) smolts from the White Sea in a cage experiment simulating the transition from a freshwater to a marine environment. A decrease in COX, G6PDH, and 1-GPDH activities and an increase in LDH and aldolase activities were observed in juveniles with an increase in water salinity. Based on the findings, a redistribution of energy substrates between the reactions of aerobic and anaerobic metabolism towards higher anaerobic ATP synthesis was assumed for pink salmon. This may indicate that adaptive mechanisms rearrange metabolism to provide energy for osmoregulation in pink salmon juveniles when the salinity changes in their habitat.

In Silico Approach for Assessment of the Anti-tumor Potential of Cannabinoid Compounds by Targeting Glucose-6-Phosphate Dehydrogenase Enzyme.

Glucose-6-phosphate dehydrogenase (G6PD) is a pentose phosphate pathway (PPP) enzyme that generates NADPH, which is required for cellular redox equilibrium and reductive biosynthesis. It has been demonstrated that abnormal G6PD activation promotes cancer cell proliferation and metastasis. To date, no G6PD inhibitor has passed clinical testing successfully enough to be launched as a medicine. As a result, in this investigation, cannabinoids were chosen to evaluate their anticancer potential by targeting G6PD. Molecular docking indicated that three molecules, Tetrahydrocannabinolic acid (THCA), Cannabichromenic acid (CBCA), and tetrahydrocannabivarin (THCV), have the highest binding affinities for G6PD of -8.61, -8.39, and 8.01 Kcal mol. ADMET analysis found that all of them were safe prospective drug candidates. Molecular dynamics (MD) simulation and MM-PBSA analysis confirm the structural compactness and lower conformational variation of protein-ligand complexes, thereby maintaining structural stability and rigidity. Thus, our in silico investigation exhibited all three cannabinoids as potential competitive inhibitors of G6PD.

Bioorthogonal Regulated Metabolic Balance for Promotion of Ferroptosis and Mild Photothermal Therapy.

The nanozyme with NADPH oxidase (NOX)-like activity can promote the consumption of NADPH and the generation of free radicals. In consideration of that the upregulation of glucose-6-phosphate dehydrogenase (G6PD) would accelerate the compensation production of NADPH, for inhibition of G6PD activity, our designed bioorthogonal nanozyme can in situ catalyze pro-DHEA to produce G6PD inhibitor and dehydroepiandrosterone (DHEA) drugs to inhibit G6PD activity. Therefore, the well-defined platform can disrupt NADPH homeostasis, leading to the collapse of the antioxidant defense system in the tumor cells. The enzyme-like activity of PdCuFe is further enhanced when irradiated by NIR-II light. The destruction of NADPH homeostasis can promote ferroptosis and, in turn, facilitate mild photothermal therapy. Our design can realize NADPH depletion and greatly improve the therapeutic effect through metabolic regulation, which may provide inspiration for the design of bioorthogonal catalysis.

Methaemoglobin as a surrogate marker of primaquine antihypnozoite activity in Plasmodium vivax malaria: A systematic review and individual patient data meta-analysis.

The 8-aminoquinolines, primaquine and tafenoquine, are the only available drugs for the radical cure of Plasmodium vivax hypnozoites. Previous evidence suggests that there is dose-dependent 8-aminoquinoline induced methaemoglobinaemia and that higher methaemoglobin concentrations are associated with a lower risk of P. vivax recurrence. We undertook a systematic review and individual patient data meta-analysis to examine the utility of methaemoglobin as a population-level surrogate endpoint for 8-aminoquinoline antihypnozoite activity to prevent P. vivax recurrence. We conducted a systematic search of Medline, Embase, Web of Science, and the Cochrane Library, from 1 January 2000 to 29 September 2022, inclusive, of prospective clinical efficacy studies of acute, uncomplicated P. vivax malaria mono-infections treated with radical curative doses of primaquine. The day 7 methaemoglobin concentration was the primary surrogate outcome of interest. The primary clinical outcome was the time to first P. vivax recurrence between day 7 and day 120 after enrolment. We used multivariable Cox proportional-hazards regression with site random-effects to characterise the time to first recurrence as a function of the day 7 methaemoglobin percentage (log base 2 transformed), adjusted for the partner schizonticidal drug, the primaquine regimen duration as a proxy for the total primaquine dose (mg base/kg), the daily primaquine dose (mg/kg), and other factors. The systematic review protocol was registered with PROSPERO (CRD42023345956). We identified 219 P. vivax efficacy studies, of which 8 provided relevant individual-level data from patients treated with primaquine; all were randomised, parallel arm clinical trials assessed as having low or moderate risk of bias. In the primary analysis data set, there were 1,747 patients with normal glucose-6-phosphate dehydrogenase (G6PD) activity enrolled from 24 study sites across 8 different countries (Indonesia, Brazil, Vietnam, Thailand, Peru, Colombia, Ethiopia, and India). We observed an increasing dose-response relationship between the daily weight-adjusted primaquine dose and day 7 methaemoglobin level. For a given primaquine dose regimen, an observed doubling in day 7 methaemoglobin percentage was associated with an estimated 30% reduction in the risk of P. vivax recurrence (adjusted hazard ratio = 0.70; 95% confidence interval [CI] [0.57, 0.86]; p = 0.0005). These pooled estimates were largely consistent across the study sites. Using day 7 methaemoglobin as a surrogate endpoint for recurrence would reduce required sample sizes by approximately 40%. Study limitations include the inability to distinguish between recrudescence, reinfection, and relapse in P. vivax recurrences. For a given primaquine regimen, higher methaemoglobin on day 7 was associated with a reduced risk of P. vivax recurrence. Under our proposed causal model, this justifies the use of methaemoglobin as a population-level surrogate endpoint for primaquine antihypnozoite activity in patients with P. vivax malaria who have normal G6PD activity.

Evaluation of Glucose 6-Phosphate Dehydrogenase, Pyruvate Kinase, and New Generation Inflammation Biomarkers in Prolonged Neonatal Jaundice.

Background and Objectives: To evaluate the clinical findings of glucose 6-phosphate dehydrogenase (G6PD) and pyruvate kinase (PK) deficiency in prolonged jaundice and to determine whether the systemic immune inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), and platelet-to-lymphocyte ratio (PLR) can be used in the diagnosis of neonatal prolonged jaundice. Materials and Methods: Among full-term neonates with hyperbilirubinemia who were admitted to Medicine Hospital between January 2019 and January 2024 with the complaint of jaundice, 167 infants with a serum bilirubin level above 10 mg/dL, whose jaundice persisted after the 10th day, were included in this study. Results: G6PD activity was negatively correlated with NLR, SII, age, and hematocrit (Hct). There was a weak negative correlation between G6PD and NLR and a moderate negative correlation between G6PD activity and SII when adjusted for age and Hct. PK activity showed no significant correlation with G6PD, NLR, PLR, SII, age, and Hct. A linear relationship was observed between G6PD activity and SII and NLR. Conclusions: NLR and SII can be easily calculated in the evaluation of prolonged jaundice in G6PD deficiency has a considerable advantage. NLR and SII levels may contribute by preventing further tests for prolonged jaundice and regulating its treatment. It may be useful to form an opinion in emergencies and in early diagnostic period.

Dehydroepiandrosterone-α-2-Deoxyglucoside Exhibits Enhanced Anticancer Effects in MCF-7 Breast Cancer Cells and Inhibits Glucose-6-Phosphate Dehydrogenase Activity.

In the pentose phosphate pathway, dehydroepiandrosterone (DHEA) uncompetitively inhibits glucose-6-phosphate dehydrogenase (G6PD), reducing NADPH production and increasing oxidative stress, which can influence the onset and/or progression of several diseases, including cancer. 2-Deoxy-D-glucose (2-DG), a glucose mimetic, competes with glucose for cellular uptake, inhibiting glycolysis and competing with glucose-6-phosphate (G-6-P) for G6PD activity. In this study, we report that DHEA-α-2-DG (5), an α-covalent conjugate of DHEA and 2-DG, exhibits better anticancer activity than DHEA, 2-DG, DHEA +2-DG, and polydatin in MCF-7 cells, and reduces NADPH/NADP+ ratio in cellular assays. Invitro enzyme kinetics and molecular docking studies showed that 5 uncompetitively inhibits human G6PD activity and binds to the structural NADP+ site but not to the catalytic NADP+ site. Further combining 5 with the FDA-approved drug tamoxifen enhanced its cytotoxicity against MCF-7 cells, suggesting that it could serve as a candidate for combination of drug strategies.

Primaquine for uncomplicated Plasmodium vivax malaria in children younger than 15 years: a systematic review and individual patient data meta-analysis

Primaquine, the only widely available treatment to prevent relapsing Plasmodium vivax malaria, is produced as 15 mg tablets, and new paediatric formulations are being developed. To inform the optimal primaquine dosing regimen for children, we aimed to determine the efficacy and safety of different primaquine dose strategies in children younger than 15 years. We undertook a systematic review (Jan 1, 2000-July 26, 2024) for P vivax efficacy studies with at least one treatment group that was administered primaquine over multiple days, that enrolled children younger than 15 years, that followed up patients for at least 28 days, and that had data available for inclusion by June 30, 2022. Patients were excluded if they were aged 15 years or older, presented with severe malaria, received adjunctive antimalarials within 14 days of diagnosis, commenced primaquine more than 7 days after starting schizontocidal treatment, had a protocol violation in the original study, or were missing data on age, sex, or primaquine dose. Available individual patient data were collated and standardised. To evaluate efficacy, the risk of recurrent P vivax parasitaemia between days 7 and 180 was assessed by time-to-event analysis for different total mg/kg primaquine doses (low total dose of ∼3·5 mg/kg and high total dose of ∼7 mg/kg). To evaluate tolerability and safety, the following were assessed by daily mg/kg primaquine dose (low daily dose of ∼0·25 mg/kg, intermediate daily dose of ∼0·5 mg/kg, and high daily dose of ∼1 mg/kg): gastrointestinal symptoms (vomiting, anorexia, or diarrhoea) on days 5-7, haemoglobin decrease of at least 25% to less than 7g/dL (severe haemolysis), absolute change in haemoglobin from day 0 to days 2-3 or days 5-7, and any serious adverse events within 28 days. This study is registered with PROSPERO, CRD42021278085. In total, 3514 children from 27 studies and 15 countries were included. The cumulative incidence of recurrence by day 180 was 51·4% (95% CI 47·0-55·9) following treatment without primaquine, 16·0% (12·4-20·3) following a low total dose of primaquine, and 10·2% (8·4-12·3) following a high total dose of primaquine. The hazard of recurrent P vivax parasitaemia in children younger than 15 years was reduced following primaquine at low total doses (adjusted hazard ratio [HR] 0·17, 95% CI 0·11-0·25) and high total doses (0·09, 0·07-0·12), compared with no primaquine. In 525 children younger than 5 years, the relative rates of recurrence were also reduced, with an adjusted HR of 0·33 (95% CI 0·18-0·59) for a low total dose and 0·13 (0·08-0·21) for a high total dose of primaquine compared with no primaquine. The rate of recurrence following a high total dose was reduced compared with a low dose in children younger than 15 years (adjusted HR 0·54, 95% CI 0·35-0·85) and children younger than 5 years (0·41, 0·21-0·78). Compared with no primaquine, children treated with any dose of primaquine had a greater risk of gastrointestinal symptoms on days 5-7 after adjustment for confounders, with adjusted risks of 3·9% (95% CI 0-8·6) in children not treated with primaquine, 9·2% (0-18·7) with a low daily dose of primaquine, 6·8% (1·7-12·0) with an intermediate daily dose of primaquine, and 9·6% (4·8-14·3) with a high daily dose of primaquine. In children with 30% or higher glucose-6-phosphate dehydrogenase (G6PD) activity, there were few episodes of severe haemolysis following no primaquine (0·4%, 95% CI 0·1-1·5), a low daily dose (0·0%, 0·0-1·6), an intermediate daily dose (0·5%, 0·1-1·4), or a high daily dose (0·7%, 0·2-1·9). Of 15 possibly drug-related serious adverse events in children, two occurred following a low, four following an intermediate, and nine following a high daily dose of primaquine. A high total dose of primaquine was highly efficacious in reducing recurrent P vivax parasitaemia in children compared with a low dose, particularly in children younger than 5 years. In children treated with high and intermediate daily primaquine doses compared with low daily doses, there was no increase in gastrointestinal symptoms or haemolysis (in children with 30% or higher G6PD activity), but there were more serious adverse events. Medicines for Malaria Venture, Bill & Melinda Gates Foundation, and Australian National Health and Medical Research Council.

Nitric oxide mediates positive regulation of Nostoc flagelliforme polysaccharide yield via potential S-nitrosylation of G6PDH and UGDH

Based on our previous findings that salicylic acid and jasmonic acid increased Nostoc flagelliforme polysaccharide yield by regulating intracellular nitric oxide (NO) levels, the mechanism through which NO affects polysaccharide biosynthesis in Nostoc flagelliforme was explored from the perspective of S-nitrosylation (SNO). The addition of NO donor and scavenger showed that intracellular NO had a significant positive effect on the polysaccharide yield of N. flagelliforme. To explore the mechanism, we investigated the relationship between NO levels and the activity of several key enzymes involved in polysaccharide biosynthesis, including fructose 1,6-bisphosphate aldolase (FBA), glucokinase (GK), glucose 6-phosphate dehydrogenase (G6PDH), mitochondrial isocitrate dehydrogenase (ICDH), and UDP-glucose dehydrogenase (UGDH). The enzymatic activities of G6PDH, ICDH, and UGDH were shown to be significantly correlated with the shifts in intracellular NO levels. For further validation, G6PDH, ICDH, and UGDH were heterologously expressed in Escherichia coli and purified via Ni+-NAT affinity chromatography, and subjected to a biotin switch assay and western blot analysis, which revealed that UGDH and G6PDH were susceptible to SNO. Furthermore, mass spectrometry analysis of proteins treated with S-nitrosoglutathione (GSNO) identified the SNO modification sites for UGDH and G6PDH as cysteine 423 and cysteine 249, respectively. These findings suggest that NO modulates polysaccharide biosynthesis in N. flagelliforme through SNO of UGDH and G6PDH. This reveals a potential mechanism through which NO promotes polysaccharide synthesis in N. flagelliforme, while also providing a new strategy for improving the industrial production of polysaccharides.

Analytical and operational considerations of measuring glucose 6-phosphate dehydrogenase (G6PD) activity using a fully automated assay.

This study determined the performance characteristics of a quantitative glucose-6-phosphate dehydrogenase (G6PD) assay with automated lysis and evaluated the robustness of the operational workflow following implementation in a hospital laboratory. The G6PD activity was measured in whole blood using an enzymatic quantitative test on a Roche cobas c501 analyzer with onboard lysis configuration and normalized to hemoglobin (Hb). The performance characteristics of the method and stability of G6PD in whole blood collected in EDTA-containing tubes were evaluated, and the reference interval was established on a population of healthy individuals (n = 279). The robustness of this automated workflow for sample lysis was evaluated during validation and after implementation for routine clinical use for 18 months and in 2,181 patients. The G6PD assay was linear from 0.7 to 16.5 U/g Hb. Inter- and intra-assay precision using control and patient samples was below 12%. The G6PD results correlated well with a reference laboratory method (r = 0.96, y = 0.9615x - 1.222). The reference interval in our population was 9.8 to 15.5 U/g Hb. There were no interferences by lipemia and icteria, although grossly hemolyzed specimens may be affected. The testing workflow requires analyzing samples within minutes from mixing and loading into the instrument to avoid sample sedimentation. Measures to repeat samples with Hb 8.0g/dL or less identified sedimented samples. In our patient population, 10.6% and 5.8% of the total males and females tested were G6PD deficient, respectively. The G6PD assay with automated lysis is acceptable for patient testing. Several measures ensured the robustness of this workflow in a hospital laboratory.

Alterations of urine microRNA-7977/G6PD level in patients with diabetic kidney disease and its association with dysfunction of albumin-induced autophagy in proximal epithelial tubular cells.

Diabetic kidney disease (DKD) remains as one of the leading long-term complications of type 2 diabetic mellitus (T2DM). Studies have shown that decreased expression of glucose-6-phosphate dehydrogenase (G6PD) plays an important role in DKD. However, the upstream and downstream pathways of G6PD downregulation leading to DKD have not been elucidated. We conducted a series of studies including clinical study, animal studies, and in vitro studies to explore this. First, a total of 90 subjects were evaluated including 30 healthy subjects, 30 patients with T2DM, and 30 patients with DKD. The urinary G6PD activity and its association with the clinical markers were analyzed. Multivariate linear regression analysis was used to analyze the risk factors of urinary G6PD in these patients. Then, microRNAs that were differentially expressed in urine and could bind and degrade G6PD were screened and verified in patients with DKD. After that, high glucose (HG)-cultured human kidney cells (HK-2) and Zucker diabetic fatty (ZDF) rats were used to test the roles of miR-7977/G6PD/albumin-induced autophagy in DKD. Beclin and P62 were used as markers of kidney autophagy indicators. A dual-luciferase reporter assay system was used to test the binding of G6PD by mir-7977. The plasma and urinary G6PD activity were decreased significantly in patients with DKD, accompanied by increased urinary mir-7977 level. The fasting plasma glucose (FPG), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and urinary albumin excretion were independent predictors of urinary G6PD activity, according to multiple linear regression analysis. The increased expression of miR-7977 and decreased expression of G6PD were also found in the kidney of ZDF rats with early renal tubular damage. The correlation analysis showed that beclin protein expression levels were positively correlated with kidney G6PD activity, whereas P62 protein expression was negatively correlated with kidney G6PD activity in rats. In HK-2 cells cultured with normal situation, a low level of albumin could induce autophagy along with the stimulation of G6PD, although this was impaired under high glucose. Overexpression of G6PD reversed albumin-induced autophagy in HK-2 cells under high glucose. Further study revealed that G6PD was a downstream target of miR-7977. Inhibition of miR-7977 expression led to significantly increased expression of G6PD and reversed the effects of high glucose on albumin-induced autophagy. In conclusion, our study supports a new mechanism of G6PD downregulation in DKD. Therapeutic measures targeting the miR-7977/G6PD/autophagy signaling pathway may help in the prevention and treatment of DKD.NEW & NOTEWORTHY This study provides new evidence that reduced glucose-6-phosphate dehydrogenase (G6PD) may damage the endocytosis of renal tubular epithelial cells by reducing albumin-induced autophagy. More importantly, for the first time, our study has provided evidence from humans that the decrease in urinary G6PD activity is positively associated with renal injury, and abnormal glucose and lipid metabolism may be important reasons for reduced G6PD levels. Increased miR-7977 may at least in part explain the downregulation of G6PD.

Membrane Damage and Metabolic Disruption as the Mechanisms of Linalool against Pseudomonas fragi: An Amino Acid Metabolomics Study.

Pseudomonas fragi (P. fragi) is usually detected in low-temperature meat products, and seriously threatens food safety and human health. Therefore, the study investigated the antibacterial mechanism of linalool against P. fragi from membrane damage and metabolic disruption. Results from field-emission transmission electron microscopy (FETEM) and atomic force microscopy (AFM) showed that linalool damage membrane integrity increases surface shrinkage and roughness. According to Fourier transform infrared (FTIR) spectra results, the components in the membrane underwent significant changes, including nucleic acid leakage, carbohydrate production, protein denaturation and modification, and fatty acid content reduction. The data obtained from amino acid metabolomics indicated that linalool caused excessive synthesis and metabolism of specific amino acids, particularly tryptophan metabolism and arginine biosynthesis. The reduced activities of glucose 6-phosphate dehydrogenase (G6PDH), malate dehydrogenase (MDH), and phosphofructokinase (PFK) suggested that linalool impair the respiratory chain and energy metabolism. Meanwhile, genes encoding the above enzymes were differentially expressed, with pfkB overexpression and zwf and mqo downregulation. Furthermore, molecular docking revealed that linalool can interact with the amino acid residues of G6DPH, MDH and PFK through hydrogen bonds. Therefore, it is hypothesized that the mechanism of linalool against P. fragi may involve cell membrane damage (structure and morphology), disturbance of energy metabolism (TCA cycle, EMP and HMP pathway) and amino acid metabolism (cysteine, glutamic acid and citrulline). These findings contribute to the development of linalool as a promising antibacterial agent in response to the food security challenge.

Methanolic extracts of litchi (Litchi chinensis Sonn.): A novel approach of targeting glucose-6-phosphate dehydrogenase for liver cancer therapy

Cancer metabolism has emerged as a potential target for innovative therapeutic approaches in the treatment of cancer. Cancer metabolism has received much attention, particularly in relation to glucose metabolism. It has been observed that human malignancies have high levels of glucose-6-phosphate dehydrogenase (G6PD) activity which is an important enzyme of glucose metabolism. This overactivity is associated with the cell death and angiogenesis, highlighting its potential as a viable target for cancer treatment. This study was conducted to examine the methanolic extracts from the seeds, bark and leaves of litchi (Litchi chinensis Sonn.) in order to discover effective compounds targeting G6PD and potentially active entities against liver cancer. Plant extract screening for the target protein was carried out through enzymatic activity assay. The recombinant plasmid pET-24a-HmG6PD was expressed in E. coli (BL21-DE3) strain, then purified and assessed using metal affinity chromatography with Ni-NTA columns and SDS-PAGE. The cytotoxicity of plant extracts against liver cancer HepG2 cells was assessed using the MTT assay. All three extracts demonstrated significant inhibitory effects (>80% inhibition) against G6PD. They were then subjected to testing at various concentrations, and their IC50 values were subsequently determined. The extracts of litchi (leaf, IC50: 1.199 μg/mL; bark, IC50: 2.350 μg/mL; seeds, IC50: 1.238 μg/mL) displayed significant inhibition of G6PD activity at lower concentrations. Subsequently, the leaf extract of litchi was further assessed for its impact on HepG2 cell lines in a dose-dependent manner and exhibited strong potential as an inhibitor of cancer cell progression. Moreover, the results of acute toxicity study in mice revealed nontoxic effects of litchi leaf extract on hepatocytes. The results imply that Litchi chinensis leaf extract could be considered as a promising candidate for safer drug development in the treatment of liver cancer.

Associations between COVID-19 and Glucose-6-Phosphate Dehydrogenase Activity in Brazil.

Glucose-6 phosphate dehydrogenase deficiency (G6PDd) was suggested as a risk factor for severe disease in patients with COVID-19. We evaluated clinical outcomes and glucose-6 phosphate dehydrogenase (G6PD) activity during and after illness in patients with COVID-19. This prospective cohort study included adult participants (≥18 years old) who had clinical and/or radiological COVID-19 findings or positive reverse transcription-polymerase chain reaction results. Epidemiological and clinical data were extracted from electronic medical records. Glucose-6 phosphate dehydrogenase activity was measured using SD Biosensor STANDARD G6PD® equipment on admission and 1 year after discharge. Samples were genotyped for the three most common single nucleotide polymorphisms for G6PDd in the Brazilian Amazon. Seven hundred fifty-three patients were included, of whom 123 (16.3%) were G6PD deficient. There was no difference between groups regarding the risks of hospitalization (P = 0.740) or invasive mechanical ventilation (P = 0.31), but the risk of death was greater in patients with normal G6PD levels (P = 0.022). Only 29 of 116 participants (25%) carried the African G6PDd genotype. Of 30 participants tested as G6PD deficient during disease, only 11 (36.7%) results agreed 1 year after discharge. In conclusion, this study does not demonstrate an association of G6PDd with severity of COVID-19. Limitations of the test for detecting enzyme levels during COVID-19 illness were demonstrated by genotyping and retesting after the disease period. Care must be taken when screening for G6PDd in patients with acute COVID-19.

Perspectives of healthcare professionals on training for quantitative G6PD testing during implementation of tafenoquine in Brazil (QualiTRuST Study).

Effective radical cure of Plasmodium vivax malaria is essential for malaria elimination in Brazil. P. vivax radical cure requires administration of a schizonticide, such as chloroquine, plus an 8-aminoquinoline. However, 8-aminoquinolines cause hemolysis in individuals with glucose-6-phosphate dehydrogenase (G6PD) deficiency, requiring prior screening to exclude those at risk. Brazil is pioneering the implementation of tafenoquine, a single-dose 8-aminoquinoline indicated for P. vivax patients with >70% of normal G6PD activity. Tafenoquine implementation in Manaus and Porto Velho, two municipalities located in the western Brazilian Amazon, included comprehensive training of healthcare professionals (HCPs) on point-of-care quantitative G6PD testing and a new treatment algorithm for P. vivax radical cure incorporating tafenoquine. Training was initially provided to higher-level facilities (phase one) and later adapted for primary care units (phase two). This study analyzed HCP experiences during training and implementation and identified barriers and facilitators. In-depth interviews and focus discussion groups were conducted 30 days after each training for a purposive random sample of 115 HCPs. Thematic analysis was employed using MAXQDA software, analyzing data through inductive and deductive coding. Analysis showed that following the initial training for higher-level facilities, some HCPs did not feel confident performing quantitative G6PD testing and prescribing the tafenoquine regimen. Modifications to the training in phase two resulted in an improvement in understanding the implementation process of the G6PD test and tafenoquine, as well as in the knowledge acquired by HCPs. Additionally, knowledge gaps were addressed through in situ training, peer communication via a messaging app, and educational materials. Training supported effective deployment of the new tools in Manaus and Porto Velho and increased awareness of the need for pharmacovigilance. A training approach for nationwide implementation of these tools was devised. Implementing quantitative G6PD testing and tafenoquine represents a significant shift in P. vivax malaria case management. Consistent engagement with HCPs is needed to overcome challenges in fully integrating these tools within the Brazilian health system.

Kinetics of glucose-6-phosphate dehydrogenase (G6PD) activity during Plasmodium vivax infection: implications for early radical malaria treatment

BackgroundPlasmodium vivax relapses due to dormant liver hypnozoites can be prevented with primaquine. However, the dose must be adjusted in individuals with glucose-6-phosphate-dehydrogenase (G6PD) deficiency. In French Guiana, assessment of G6PD activity is typically delayed until day (D)14 to avoid the risk if misclassification. This study assessed the kinetics of G6PD activity throughout P. vivax infection to inform the timing of treatment.MethodsFor this retrospective monocentric study, data on G6PD activity between D1 and D28 after treatment initiation with chloroquine or artemisinin-based combination therapy were collected for patients followed at Cayenne Hospital, French Guiana, between January 2018 and December 2020. Patients were divided into three groups based on the number of available G6PD activity assessments: (i) at least two measurements during the P. vivax malaria infection; (ii) two measurements: one during the current infection and one previously; (iii) only one measurement during the malaria infection.ResultsIn total, 210 patients were included (80, 20 and 110 in groups 1, 2 and 3, respectively). Data from group 1 showed that G6PD activity remained stable in each patient over time (D1, D3, D7, D14, D21, D28). None of the patients with normal G6PD activity during the initial phase (D1–D3) of the malaria episode (n = 44) was categorized as G6PD-deficient at D14. Patients with G6PD activity < 80% at D1 or D3 showed normal activity at D14. Sex and reticulocyte count were statistically associated with G6PD activity variation. In the whole sample (n = 210), no patient had severe G6PD deficiency (< 10%) and only three between 10 and 30%, giving a G6PD deficiency prevalence of 1.4%. Among the 100 patients from group 1 and 2, 30 patients (26.5%) were lost to follow-up before primaquine initiation.ConclusionsIn patients treated for P. vivax infection, G6PD activity did not vary over time. Therefore, G6PD activity on D1 instead of D14 could be used for primaquine dose-adjustment. This could allow earlier radical treatment with primaquine, that could have a public health impact by decreasing early recurrences and patients lost to follow-up before primaquine initiation. This hypothesis needs to be confirmed in larger prospective studies.

Exploring Appropriate Reference Intervals and Clinical Decision Limits for Glucose-6-Phosphate Dehydrogenase Activity in Individuals From Guangzhou, China.

Quantitative detection of glucose-6-phosphate dehydrogenase (G6PD) is commonly done to screen for G6PD deficiency. However, current reference intervals (RIs) of G6PD are unsuitable for evaluating G6PD-activity levels with local populations or associating G6PD variants with hemolysis risk to aid clinical decision-making. We explored appropriate RIs and clinical decision limits (CDLs) for G6PD activity in individuals from Guangzhou, China. We enrolled 5,852 unrelated individuals between 2020 and 2022 and screened their samples in quantitative assays for G6PD activity. We conducted further investigations, including G6PD genotyping, thalassemia genotyping, follow-up analysis, and statistical analysis, for different groups. In Guangzhou, the RIs for the G6PD activities were 11.20-20.04 U/g Hb in male and 12.29-23.16 U/g Hb in female. The adjusted male median and normal male median (NMM) values were 15.47 U/g Hb and 15.51 U/g Hb, respectively. A threshold of 45% of the NMM could be used as a CDL to estimate the probability of G6PD variants. Our results revealed high hemolysis-risk CDLs (male: <10% of the NMM, female: <30% of the NMM), medium hemolysis-risk CDLs (male: 10%-45% of the NMM, female: 30%-79% of the NMM), and low hemolysis-risk CDLs (male: ≥ 45% of the NMM, female: ≥ 79% of the NMM). Collectively, our findings contribute to a more accurate evaluation of G6PD-activity levels within the local population and provide valuable insights for clinical decision-making. Specifically, identifying threshold values for G6PD variants and hemolysis risk enables improved prediction and management of G6PD deficiency, ultimately enhancing patient care and treatment outcomes.

Survival of transfused red blood cells from a donor with alpha-thalassemia trait in a recipient with sickle cell disease.

Post-transfusion survival of donor red blood cells (RBCs) is important for effective chronic transfusion therapy in conditions including sickle cell disease (SCD). Biotin labeling RBCs allows direct in vivo measurement of multiple donor RBC units simultaneously post-transfusion. In an observational trial of patients with SCD receiving monthly chronic transfusion therapy, aliquots of RBCs from one transfusion episode were biotin-labeled and infused along with the unlabeled RBC units. Serial blood samples were obtained to measure RBC survival. Donor units were tested for RBC indices, hemoglobin fractionation, and glucose-6-phosphate dehydrogenase (G6PD) enzyme activity. For microcytic donor RBCs (MCV < 70 fL), HBA1 and HBA2 genetic testing was performed on whole blood. We present one recipient, a pediatric patient with SCD and splenectomy who received two RBC units with aliquots from each unit labeled at distinct biotin densities (2 and 18 μg/mL biotin). One donor unit was identified to have microcytosis (MCV 68.5 fL after biotinylation); whole blood sample obtained at a subsequent donation showed 2-gene deletion alpha-thalassemia trait (ɑ-3.7kb/ɑ-3.7kb) and normal serum ferritin. G6PD activity was >60% of normal mean for both. The RBCs with alpha-thalassemia RBC had accelerated clearance and increased surface phosphatidylserine post-transfusion, as compared with the normocytic RBC (half life 65 vs. 86 days, respectively). Post-transfusion RBC survival may be lower for units from donors with alpha-thalassemia trait, although the impact of thalassemia trait donors on transfusion efficacy requires further study.

Deficiency of betaine-homocysteine methyltransferase activates glucose-6-phosphate dehydrogenase (G6PD) by decreasing arginine methylation of G6PD in hepatocellular carcinogenesis.

Betaine-homocysteine methyltransferase (BHMT) regulates protein methylation and is correlated with tumorigenesis; however, the effects and regulation of BHMT in hepatocarcinogenesis remain largely unexplored. Here, we determined the clinical significance of BHMT in the occurrence and progression of hepatocellular carcinoma (HCC) using tissue samples from 198 patients. BHMT was to be frequently found (86.6%) expressed at relatively low levels in HCC tissues and was positively correlated with the overall survival of patients with HCC. Bhmt overexpression effectively suppressed several malignant phenotypes in hepatoma cells in vitro and in vivo, whereas complete knockout of Bhmt (Bhmt-/-) produced the opposite effect. We combined proteomics, metabolomics, and molecular biological strategies and detected that Bhmt-/- promoted hepatocarcinogenesis and tumor progression by enhancing the activity of glucose-6-phosphate dehydrogenase (G6PD) and PPP metabolism in DEN-induced HCC mouse and subcutaneous tumor-bearing models. In contrast, restoration of Bhmt with an AAV8-Bhmt injection or pharmacological inhibition of G6PD attenuated hepatocarcinogenesis. Additionally, coimmunoprecipitation identified monomethylated modifications of the G6PD, and BHMT regulated the methylation of G6PD. Protein sequence analysis, generation and application of specific antibodies, and site-directed mutagenesis indicated G6PD methylation at the arginine residue 246. Furthermore, we established bidirectionally regulated BHMT cellular models combined with methylation-deficient G6PD mutants to demonstrate that BHMT potentiated arginine methylation of G6PD, thereby inhibiting G6PD activity, which in turn suppressed hepatocarcinogenesis. Taken together, this study reveals a new methylation-regulatory mechanism in hepatocarcinogenesis owing to BHMT deficiency, suggesting a potential therapeutic strategy for HCC treatment.