ABSTRACT
Critical illness in COVID-19 is an extreme and clinically homogeneous disease phenotype that we have previously shown1 to be highly efficient for discovery of genetic associations2. Despite the advanced stage of illness at presentation, we have shown that host genetics in patients who are critically ill with COVID-19 can identify immunomodulatory therapies with strong beneficial effects in this group3. Here we analyse 24,202 cases of COVID-19 with critical illness comprising a combination of microarray genotype and whole-genome sequencing data from cases of critical illness in the international GenOMICC (11,440 cases) study, combined with other studies recruiting hospitalized patients with a strong focus on severe and critical disease: ISARIC4C (676 cases) and the SCOURGE consortium (5,934 cases). To put these results in the context of existing work, we conduct a meta-analysis of the new GenOMICC genome-wide association study (GWAS) results with previously published data. We find 49 genome-wide significant associations, of which 16 have not been reported previously. To investigate the therapeutic implications of these findings, we infer the structural consequences of protein-coding variants, and combine our GWAS results with gene expression data using a monocyte transcriptome-wide association study (TWAS) model, as well as gene and protein expression using Mendelian randomization. We identify potentially druggable targets in multiple systems, including inflammatory signalling (JAK1), monocyte-macrophage activation and endothelial permeability (PDE4A), immunometabolism (SLC2A5 and AK5), and host factors required for viral entry and replication (TMPRSS2 and RAB2A).
Subject(s)
COVID-19 , Critical Illness , Genetic Predisposition to Disease , Genetic Variation , Genome-Wide Association Study , Humans , COVID-19/genetics , Genetic Predisposition to Disease/genetics , Genetic Variation/genetics , Genotype , Genotyping Techniques , Monocytes/metabolism , Phenotype , rab GTP-Binding Proteins/genetics , Transcriptome , Whole Genome SequencingABSTRACT
Temperature is an important control factor for biologics biomanufacturing in precision fermentation. Here, we explored a highly responsive low temperature-inducible genetic system (LowTempGAL) in the model yeast Saccharomyces cerevisiae. Two temperature biosensors, a heat-inducible degron and a heat-inducible protein aggregation domain, were used to regulate the GAL activator Gal4p, rendering the leaky LowTempGAL systems. Boolean-type induction was achieved by implementing a second-layer control through low-temperature-mediated repression on GAL repressor gene GAL80, but suffered delayed response to low-temperature triggers and a weak response at 30°C. Application potentials were validated for protein and small molecule production. Proteomics analysis suggested that residual Gal80p and Gal4p insufficiency caused suboptimal induction. 'Turbo' mechanisms were engineered through incorporating a basal Gal4p expression and a galactose-independent Gal80p-supressing Gal3p mutant (Gal3Cp). Varying Gal3Cp configurations, we deployed the LowTempGAL systems capable for a rapid stringent high-level induction upon the shift from a high temperature (37-33°C) to a low temperature (≤30°C). Overall, we present a synthetic biology procedure that leverages 'leaky' biosensors to deploy highly responsive Boolean-type genetic circuits. The key lies in optimisation of the intricate layout of the multi-factor system. The LowTempGAL systems may be applicable in non-conventional yeast platforms for precision biomanufacturing.
Subject(s)
Gene Expression Regulation, Fungal , Saccharomyces cerevisiae Proteins , Saccharomyces cerevisiae , Transcription Factors , Saccharomyces cerevisiae/genetics , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Saccharomyces cerevisiae Proteins/genetics , Transcription Factors/metabolism , Transcription Factors/genetics , Repressor Proteins/metabolism , Repressor Proteins/genetics , DNA-Binding Proteins/metabolism , DNA-Binding Proteins/genetics , Cold Temperature , Galactose/metabolism , Biosensing TechniquesABSTRACT
MOTIVATION: The identification of minimal genetic interventions that modulate metabolic processes constitutes one of the most relevant applications of genome-scale metabolic models (GEMs). The concept of Minimal Cut Sets (MCSs) and its extension at the gene level, genetic Minimal Cut Sets (gMCSs), have attracted increasing interest in the field of Systems Biology to address this task. Different computational tools have been developed to calculate MCSs and gMCSs using both commercial and open-source software. RESULTS: Here, we present gMCSpy, an efficient Python package to calculate gMCSs in GEMs using both commercial and non-commercial optimization solvers. We show that gMCSpy substantially overperforms our previous computational tool GMCS, which exclusively relied on commercial software. Moreover, we compared gMCSpy with recently published competing algorithms in the literature, finding significant improvements in both accuracy and computation time. All these advances make gMCSpy an attractive tool for researchers in the field of Systems Biology for different applications in health and biotechnology. AVAILABILITY AND IMPLEMENTATION: The Python package gMCSpy and the data underlying this manuscript can be accessed at: https://github.com/PlanesLab/gMCSpy.
Subject(s)
Algorithms , Software , Systems Biology , Systems Biology/methods , Genome , Computational Biology/methodsABSTRACT
BACKGROUND: Monoallelic loss-of-function IKZF1 (IKAROS) variants cause B-cell deficiency or combined immunodeficiency, whereas monoallelic gain-of-function (GOF) IKZF1 variants have recently been reported to cause hypergammaglobulinemia, abnormal plasma cell differentiation, autoimmune and allergic manifestations, and infections. OBJECTIVE: We studied 7 relatives with autoimmune/inflammatory and lymphoproliferative manifestations to identify the immunologic disturbances and the genetic cause of their disease. METHODS: We analyzed biopsy results and performed whole-exome sequencing and immunologic studies. RESULTS: Disease onset occurred at a mean age of 25.2 years (range, 10-64, years). Six patients suffered from autoimmune/inflammatory diseases, 4 had confirmed IG4-related disease (IgG4-RD), and 5 developed B-cell malignancies: lymphoma in 4 and multiple myeloma in the remaining patient. Patients without immunosuppression were not particularly prone to infectious diseases. Three patients suffered from life-threatening coronavirus disease 2019 pneumonia, of whom 1 had autoantibodies neutralizing IFN-α. The recently described IKZF1 GOF p.R183H variant was found in the 5 affected relatives tested and in a 6-year-old asymptomatic girl. Immunologic analysis revealed hypergammaglobulinemia and high frequencies of certain lymphocyte subsets (exhausted B cells, effector memory CD4 T cells, effector memory CD4 T cells that have regained surface expression of CD45RA and CD28-CD57+ CD4+ and CD8+ T cells, TH2, and Tfh2 cells) attesting to immune dysregulation. Partial clinical responses to rituximab and corticosteroids were observed, and treatment with lenalidomide, which promotes IKAROS degradation, was initiated in 3 patients. CONCLUSIONS: Heterozygosity for GOF IKZF1 variants underlies autoimmunity/inflammatory diseases, IgG4-RD, and B-cell malignancies, the onset of which may occur in adulthood. Clinical and immunologic data are similar to those for patients with unexplained IgG4-RD. Patients may therefore benefit from treatments inhibiting pathways displaying IKAROS-mediated overactivity.
ABSTRACT
The obligate intracellular parasite Toxoplasma gondii can infect and replicate in any warm-blooded cell tested to date, but much of our knowledge about T. gondii cell biology comes from just one host cell type: human foreskin fibroblasts (HFFs). To expand our knowledge of host-parasite lipid interactions, we studied T. gondii in intestinal epithelial cells, the first site of host-parasite contact following oral infection and the exclusive site of parasite sexual development in feline hosts. We found that highly metabolic Caco-2 cells are permissive to T. gondii growth even when treated with high levels of linoleic acid (LA), a polyunsaturated fatty acid (PUFA) that kills parasites in HFFs. Caco-2 cells appear to sequester LA away from the parasite, preventing membrane disruptions and lipotoxicity that characterize LA-induced parasite death in HFFs. Our work is an important step toward understanding host-parasite interactions in feline intestinal epithelial cells, an understudied but important cell type in the T. gondii life cycle.
ABSTRACT
We explored patient front-line treatment preferences in newly diagnosed stage III/IV classic Hodgkin lymphoma (cHL). The CONNECT patient survey, administered online from 30 December 2020 to 1 March 2021, examined preferences overall and by age at diagnosis in 182 adult patients diagnosed with stage III/IV cHL within the past 10 years in the United States. At diagnosis, patients' median age was 36 years; 66% of patients were younger (aged 16-41 years) and 34% older (aged 42-85 years). When asked about initial treatment goals, 74% of patients ranked cure as their first or second goal (86% younger vs. 52% older patients; p < 0.001). At diagnosis, 72% of patients preferred aggressive treatment, and 85% were willing to accept more short-term risks in exchange for a better-working therapy long term. For long-term risks, younger versus older patients were significantly more concerned about second cancers (p < 0.001) and fertility issues (p = 0.007), whereas older patients were more concerned about lung damage (p = 0.028) and infections (p < 0.001). Most patients (94%) reported having a caregiver at some point, but 99% of these patients retained some control of treatment decisions. Collectively, these survey results highlight patient treatment preferences and differences in treatment goals and long-term side effect concerns based on patient age.
Subject(s)
Hodgkin Disease , Adult , Humans , Hodgkin Disease/drug therapy , Hodgkin Disease/pathology , Cross-Sectional Studies , Patient Preference , Surveys and QuestionnairesABSTRACT
A fundamental parameter to determine how electromagnetic waves interfere is their relative phase, and achieving a fine control over it enables a wide range of interferometric applications. Existing phase control methods rely on modifying the optical path length either by changing the path followed by the light or by altering the thickness or index of refraction of an optical element in the setup. In this Letter, we present a novel, to the best of our knowledge, method, based on acousto-optic modulators (AOMs), which allows adjusting the phase by shifting the frequency of the light in a segment of its path. Since the amount of phase shift depends on the length of the segment, an optical fiber is used to realize a 2π shift. Two experimental implementations are described which deal with different sources of phase fluctuations. The first addresses fluctuations resulting from the optical fiber, while the second tackles unwanted variations originating from the AOMs.
ABSTRACT
Aim: To understand US physicians' frontline (1L) treatment preferences/decision-making for stage III/IV classic Hodgkin lymphoma (cHL). Materials & methods: Medical oncologists and/or hematologists (≥2 years' practice experience) who treat adults with stage III/IV cHL were surveyed online (October-November 2020). Results: Participants (n = 301) most commonly considered trial efficacy/safety data and national guidelines when selecting 1L cHL treatments. Most physicians (91%) rated overall survival (OS) as the most essential attribute when selecting 1L treatment. Variability was seen among regimen selection for hypothetical newly diagnosed patients, with OS cited as the most common reason for regimen selection. Conclusion: While treatment selection varied based on patient characteristics, US physicians consistently cited OS as the top factor considered when selecting a 1L treatment for cHL.
Classic Hodgkin lymphoma (cHL) is a type of cancer that grows in lymph nodes. The researchers created a survey to assess how doctors in the USA choose medicine to treat patients who are newly diagnosed with an advanced stage of cHL (stage 3 or 4 out of 4 stages). We surveyed 301 doctors who treat patients with cHL. When choosing a medicine to treat cHL, most doctors said they consider results from research studies, how well the medicine works, information on the medicine's safety and recommendations in official guidelines. Most doctors said that overall survival (how long the patient survives after being diagnosed with cHL) is the most important outcome they consider when choosing a medicine to treat cHL. During the survey, doctors saw four unique patient profiles. These profiles differed in age, disease stage (how far along the cHL is) and other illnesses the patient has. While medicine choice was different across profiles, overall survival was still the reason for choosing each individual patient's medicine. These survey results show that doctors in the USA highly consider overall survival when choosing medicine for patients newly diagnosed with an advanced stage of cHL.
Subject(s)
Clinical Decision-Making , Hodgkin Disease , Physicians , Adult , Humans , Hodgkin Disease/drug therapy , Hodgkin Disease/pathology , Neoplasm Staging , Survival AnalysisABSTRACT
Rationale: Idiopathic pulmonary fibrosis (IPF) is a devastating disease characterized by limited treatment options and high mortality. A better understanding of the molecular drivers of IPF progression is needed. Objectives: To identify and validate molecular determinants of IPF survival. Methods: A staged genome-wide association study was performed using paired genomic and survival data. Stage I cases were drawn from centers across the United States and Europe and stage II cases from Vanderbilt University. Cox proportional hazards regression was used to identify gene variants associated with differential transplantation-free survival (TFS). Stage I variants with nominal significance (P < 5 × 10-5) were advanced for stage II testing and meta-analyzed to identify those reaching genome-wide significance (P < 5 × 10-8). Downstream analyses were performed for genes and proteins associated with variants reaching genome-wide significance. Measurements and Main Results: After quality controls, 1,481 stage I cases and 397 stage II cases were included in the analysis. After filtering, 9,075,629 variants were tested in stage I, with 158 meeting advancement criteria. Four variants associated with TFS with consistent effect direction were identified in stage II, including one in an intron of PCSK6 (proprotein convertase subtilisin/kexin type 6) reaching genome-wide significance (hazard ratio, 4.11 [95% confidence interval, 2.54-6.67]; P = 9.45 × 10-9). PCSK6 protein was highly expressed in IPF lung parenchyma. PCSK6 lung staining intensity, peripheral blood gene expression, and plasma concentration were associated with reduced TFS. Conclusions: We identified four novel variants associated with IPF survival, including one in PCSK6 that reached genome-wide significance. Downstream analyses suggested that PCSK6 protein plays a potentially important role in IPF progression.
Subject(s)
Genome-Wide Association Study , Idiopathic Pulmonary Fibrosis , Humans , Lung , Proportional Hazards Models , Europe , Serine Endopeptidases , Proprotein ConvertasesABSTRACT
BACKGROUND AND AIMS: Familial inflammatory bowel disease (IBD) history is a controversial prognostic factor in IBD. We aimed to evaluate the impact of a familial history of IBD on the use of medical and surgical treatments in the biological era. METHODS: Patients included in the prospectively maintained ENEIDA database and diagnosed with IBD after 2005 were included. Familial forms were defined as those cases with at least one first-degree relative diagnosed with IBD. Disease phenotype, the use of biological agents, or surgical treatments were the main outcomes. RESULTS: A total of 5263 patients [2627 Crohn's disease (CD); 2636 ulcerative colitis (UC)] were included, with a median follow-up of 31 months. Of these, 507 (10%) corresponded to familial forms. No clinical differences were observed between familial and sporadic IBD forms except a lower age at IBD diagnosis and a higher rate of males in familial forms of UC. In CD, the proportions of patients treated with thiopurines (54.4% vs 46.7%; P = .015) and survival time free of thiopurines (P = .009) were lower in familial forms. No differences were found regarding the use of biological agents. Concerning surgery, a higher rate of intestinal resections was observed in sporadic CD (14.8% vs 9.9%, P = .027). No differences were observed in UC. CONCLUSIONS: In the era of biological therapies, familial and sporadic forms of IBD show similar phenotypes and are managed medically in a similar way; whether these is due to lack of phenotypical differences or an effect of biological therapies is uncertain. What is already known on this topic: IBD's etiopathogenesis points to an interaction between environmental and genetic factors, being familial history a controversial prognostic factor. Biological agents use and need for surgery regarding familial or sporadic forms of IBDs present conflicting results. What this study adds: Familial and sporadic forms of IBD have similar phenotypes and are managed medically and surgically in a similar way. How this study might affect research, practice or policy: Familial aggregation should not be considered a factor associated with more aggressive disease.
ABSTRACT
BACKGROUND: Genome-wide association studies of COVID-19 severity have been carried out mostly on European or East Asian populations with small representation of other world regions. Here we explore the worldwide distribution and linkage disequilibrium (LD) patterns of genetic variants previously associated with COVID-19 severity. METHODS: We followed up the results of a large Spanish genome-wide meta-analysis on 26 populations from the 1000 Genomes Project by calculating allele frequencies and LD scores of the nine most significant SNPs. We also used the entire set of summary statistics to compute polygenic risk scores (PRSs) and carried out comparisons at the population and continental level. RESULTS: We observed the strongest differences among continental regions for the five top SNPs in chromosome 3. European, American, and South Asian populations showed similar LD patterns. Average PRSs in South Asian and American populations were consistently higher than those observed in Europeans. While PRS distributions were similar among South Asians, the American populations showed striking differences among them. CONCLUSIONS: Considering the caveats of PRS transferability across ethnicities, our analysis showed that American populations present the highest genetic risk score, hence potentially higher propensity, for COVID-19 severity. Independent validation is warranted with additional summary statistics and phenotype data.
Subject(s)
COVID-19 , Genome-Wide Association Study , Polymorphism, Single Nucleotide , SARS-CoV-2 , Humans , COVID-19/genetics , COVID-19/epidemiology , Linkage Disequilibrium , Genetic Predisposition to Disease , Severity of Illness Index , Gene Frequency , Multifactorial InheritanceABSTRACT
Chagas disease is an infection caused by the parasite Trypanosoma cruzi, endemic in Latino America. Leveraging the three-way admixture between Native American (AMR), European (EUR) and African (AFR) populations in Latin Americans, we aimed to better understand the genetic basis of Chagas disease by performing an admixture mapping study in a Colombian population. A two-stage study was conducted, and subjects were classified as seropositive and seronegative for T. cruzi. In stage 1, global and local ancestries were estimated using reference data from the 1000 Genomes Project (1KGP), and local ancestry associations were performed by logistic regression models. The AMR ancestry showed a protective association with Chagas disease within the major histocompatibility complex region [Odds ratio (OR) = 0.74, 95% confidence interval (CI) = 0.66-0.83, lowest P-value = 4.53 × 10-8]. The fine mapping assessment on imputed genotypes combining data from stage 1 and 2 from an independent Colombian cohort, revealed nominally associated variants in high linkage disequilibrium with the top signal (rs2032134, OR = 0.93, 95% CI = 0.90-0.97, P-value = 3.54 × 10-4) in the previously associated locus. To assess ancestry-specific adaptive signals, a selective sweep scan in an AMR reference population from 1KGP together with an in silico functional analysis highlighted the Tripartite Motif family and the human leukocyte antigen genes, with crucial role in the immune response against pathogens. Furthermore, these analyses emphasized the macrophages, neutrophils and eosinophils, as key players in the defense against T. cruzi. This first admixture mapping study in Chagas disease provided novel insights underlying the host immune response in the pathogenesis of this neglected disease.
Subject(s)
Chagas Disease , Polymorphism, Single Nucleotide , Chagas Disease/genetics , Colombia , Disease Susceptibility , Hispanic or Latino , Humans , Polymorphism, Single Nucleotide/geneticsABSTRACT
BACKGROUND: Since Food and Drug Administration approval of brentuximab vedotin in combination with cyclophosphamide, doxorubicin, and prednisone (Aâ +â CHP) as initial therapy for previously untreated CD30-expressing peripheral T-cell lymphoma (PTCL), there has been limited research on real-world patient characteristics, treatment patterns, and clinical outcomes. METHODS: We retrospectively analyzed claims of patients with PTCL treated with frontline Aâ +â CHP or CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) using the Symphony Health Solutions database. Adults with International Classification of Diseases-9/10 PTCL diagnosis codes who initiated Aâ +â CHP or CHOP between November 2018 and July 2021 were included. A 1:1 propensity score matching analysis was performed that adjusted for potential confounders between groups. RESULTS: A total of 1344 patients were included (Aâ +â CHP, nâ =â 749; CHOP, nâ =â 595). Before matching, 61% were men; median age at index was 62 (Aâ +â CHP) and 69 (CHOP) years. The most common Aâ +â CHP-treated PTCL subtypes were systemic anaplastic large cell lymphoma (sALCL; 51%), PTCL-not otherwise specified (NOS; 30%), and angioimmunoblastic T-cell lymphoma (AITL; 12%); the most common CHOP-treated subtypes were PTCL-NOS (51%) and AITL (19%). After matching, similar proportions of patients treated with Aâ +â CHP and CHOP received granulocyte colony-stimulating factor (89% vs. 86%, Pâ =â .3). Fewer patients treated with Aâ +â CHP received subsequent therapy than CHOP overall (20% vs. 30%, Pâ <â .001) and specifically with the sALCL subtype (15% vs. 28%, Pâ =â .025). CONCLUSIONS: Characteristics and management of this real-world PTCL population who were older and had a higher comorbidity burden than that in the ECHELON-2 trial demonstrate the importance of retrospective studies when assessing the impact of new regimens on clinical practice.
Subject(s)
Lymphoma, T-Cell, Peripheral , Adult , Male , Humans , Female , Brentuximab Vedotin/therapeutic use , Retrospective Studies , Prednisone , Lymphoma, T-Cell, Peripheral/drug therapy , Lymphoma, T-Cell, Peripheral/pathology , Propensity Score , Antineoplastic Combined Chemotherapy Protocols/adverse effects , Cyclophosphamide/therapeutic use , DoxorubicinABSTRACT
BACKGROUND: Gastro-oesophageal reflux disease (GORD) is associated with idiopathic pulmonary fibrosis (IPF) in observational studies. It is not known if this association arises because GORD causes IPF or because IPF causes GORD, or because of confounding by factors, such as smoking, associated with both GORD and IPF. We used bidirectional Mendelian randomisation (MR), where genetic variants are used as instrumental variables to address issues of confounding and reverse causation, to examine how, if at all, GORD and IPF are causally related. METHODS: A bidirectional two-sample MR was performed to estimate the causal effect of GORD on IPF risk and of IPF on GORD risk, using genetic data from the largest GORD (78 707 cases and 288 734 controls) and IPF (4125 cases and 20 464 controls) genome-wide association meta-analyses currently available. RESULTS: GORD increased the risk of IPF, with an OR of 1.6 (95% CI 1.04-2.49; p=0.032). There was no evidence of a causal effect of IPF on the risk of GORD, with an OR of 0.999 (95% CI 0.997-1.000; p=0.245). CONCLUSIONS: We found that GORD increases the risk of IPF, but found no evidence that IPF increases the risk of GORD. GORD should be considered in future studies of IPF risk and interest in it as a potential therapeutic target should be renewed. The mechanisms underlying the effect of GORD on IPF should also be investigated.
Subject(s)
Gastroesophageal Reflux , Idiopathic Pulmonary Fibrosis , Humans , Gastroesophageal Reflux/complications , Gastroesophageal Reflux/genetics , Gastroesophageal Reflux/drug therapy , Genome-Wide Association Study , Idiopathic Pulmonary Fibrosis/genetics , Idiopathic Pulmonary Fibrosis/complicationsABSTRACT
BACKGROUND: Sepsis and associated organ failures confer substantial morbidity and mortality. Xanthine oxidoreductase (XOR) is implicated in the development of tissue oxidative damage in a wide variety of respiratory and cardiovascular disorders including sepsis and sepsis-associated acute respiratory distress syndrome (ARDS). We examined whether single nucleotide polymorphisms (SNPs) in the XDH gene (encoding XOR) might influence susceptibility to and outcome in patients with sepsis. METHODS: We genotyped 28 tag SNPs in XDH gene in the CELEG cohort, including 621 European American (EA) and 353 African American (AA) sepsis patients. Serum XOR activity was measured in a subset of CELEG subjects. Additionally, we assessed the functional effects of XDH variants utilizing empirical data from different integrated software tools and datasets. RESULTS: Among AA patients, six intronic variants (rs206805, rs513311, rs185925, rs561525, rs2163059, rs13387204), in a region enriched with regulatory elements, were associated with risk of sepsis (P < 0.008-0.049). Two out of six SNPs (rs561525 and rs2163059) were associated with risk of sepsis-associated ARDS in an independent validation cohort (GEN-SEP) of 590 sepsis patients of European descent. Two common SNPs (rs1884725 and rs4952085) in tight linkage disequilibrium (LD) provided strong evidence for association with increased levels of serum creatinine (Padjusted<0.0005 and 0.0006, respectively), suggesting a role in increased risk of renal dysfunction. In contrast, among EA ARDS patients, the missense variant rs17011368 (I703V) was associated with enhanced mortality at 60-days (P < 0.038). We found higher serum XOR activity in 143 sepsis patients (54.5 ± 57.1 mU/mL) compared to 31 controls (20.9 ± 12.4 mU/mL, P = 1.96 × 10- 13). XOR activity was associated with the lead variant rs185925 among AA sepsis patients with ARDS (P < 0.005 and Padjusted<0.01). Multifaceted functions of prioritized XDH variants, as suggested by various functional annotation tools, support their potential causality in sepsis. CONCLUSIONS: Our findings suggest that XOR is a novel combined genetic and biochemical marker for risk and outcome in patients with sepsis and ARDS.
Subject(s)
Respiratory Distress Syndrome , Sepsis , Humans , Xanthine Dehydrogenase/genetics , Genotype , Polymorphism, Single Nucleotide/genetics , Sepsis/diagnosis , Sepsis/genetics , Sepsis/complicationsABSTRACT
Astaxanthin (AX) is a carotenoid pigment with antioxidant properties widely used as a feed supplement. Wild-type strains of Phaffia rhodozyma naturally produce low AX yields, but we increased AX yields 50-fold in previous research using random mutagenesis of P. rhodozyma CBS6938 and fermentation optimization. On that study, genome changes were linked with phenotype, but relevant metabolic changes were not resolved. In this study, the wild-type and the superior P. rhodozyma mutant strains were grown in chemically defined media and instrumented fermenters. Differential kinetic, metabolomics, and transcriptomics data were collected. Our results suggest that carotenoid production was mainly associated with cell growth and had a positive regulation of central carbon metabolism metabolites, amino acids, and fatty acids. In the stationary phase, amino acids associated with the TCA cycle increased, but most of the fatty acids and central carbon metabolism metabolites decreased. TCA cycle metabolites were in abundance and media supplementation of citrate, malate, α-ketoglutarate, succinate, or fumarate increased AX production in the mutant strain. Transcriptomic data correlated with the metabolic and genomic data and found a positive regulation of genes associated with the electron transport chain suggesting this to be the main driver for improved AX production in the mutant strain.
Subject(s)
Basidiomycota , Carotenoids , Electron Transport , Carotenoids/metabolism , Basidiomycota/genetics , Basidiomycota/metabolism , Fatty Acids/metabolismABSTRACT
Pichia pastoris (Komagataella phaffii) is a fast-growing methylotrophic yeast with the ability to assimilate several carbon sources such as methanol, glucose, or glycerol. It has been shown to have outstanding secretion capability with a variety of heterologous proteins. In previous studies, we engineered P. pastoris to co-express Escherichia coli AppA phytase and the HAC1 transcriptional activator using a bidirectional promoter. Phytase production was characterized in shake flasks and did not reflect industrial conditions. In the present study, phytase expression was explored and optimized using instrumented fermenters in continuous and fed-batch modes. First, the production of phytase was investigated under glucose de-repression in continuous culture at three dilution factors, 0.5 d-1 , 1 d-1 , and 1.5 d-1 . The fermenter parameters of these cultures were used to inform a kinetic model in batch and fed-batch modes for growth and phytase production. The kinetic model developed aided to design the glucose-feeding profile of a fed-batch culture. Kinetic model simulations under glucose de-repression and fed-batch conditions identified optimal phytase productivity at the specific growth rate of 0.041 h-1 . Validation of the model simulation with experimental data confirmed the feasibility of the model to predict phytase production in our newly engineered strain. Methanol was used only to induce the expression of phytase at high cell densities. Our results showed that high phytase production required two stages, the first stage used glucose under de-repression conditions to generate biomass while expressing phytase, and stage two used methanol to induce phytase expression. The production of phytase was improved 3.5-fold by methanol induction compared to the expression with glucose alone under de-repression conditions to a final phytase activity of 12.65 MU/L. This final volumetric phytase production represented an approximate 36-fold change compared to the flask fermentations. Finally, the phytase protein produced was assayed to confirm its molecular weight, and pH and temperature profiles. This study highlights the importance of optimizing protein production in P. pastoris when using novel promoters and presents a general approach to performing bioprocess optimization in this important production host.
ABSTRACT
PURPOSE: As part of the CONNECT study, we evaluated the caregiver role in treatment decision-making when caring for patients with classic Hodgkin lymphoma (cHL) in the USA. METHODS: The CONNECT caregiver survey was administered online December 2020-March 2021 to self-identified adult caregivers of cHL patients recruited from patient referrals and online panels. The caregiver's role in treatment decision-making, health-related quality of life (HRQoL, PROMIS-Global), and work impacts (WPAI:CG) were assessed. RESULTS: We surveyed 209 caregivers (58% women; median age 47 years; 54% employed; 53% spouse/partner); 69% of patients cared for were diagnosed with cHL in the past 1-2 years, with 48% having stage III/IV cHL and 29% in remission. More spouse/partner than other caregivers were involved in caregiving at symptom onset (61% vs 27%), whereas more other than spouse/partner caregivers began after first treatment (34% vs 5%). Cure, caregivers' top treatment goal (49%), was rated higher by spouse/partner than other caregivers (56% vs 42%). More spouse/partner than other caregivers were involved in treatment option discussions with physicians (52% vs 28%), were involved in patients' treatment decisions (54% vs 23%), and were aligned with patients' treatment goals (93% vs 79%). While caregivers reported HRQoL similar to that of the general population, nearly 30% of employed caregivers reported work impairment. CONCLUSION: Cure was caregivers' top treatment goal. Spouse/partner vs other caregivers were more involved, were involved earlier, and reported greater alignment with patient treatment goals and decision-making. Caregivers reported good HRQoL; however, caregiving impacted work productivity regardless of patient relationship.
Subject(s)
Caregivers , Hodgkin Disease , Adult , Humans , Female , Middle Aged , Male , Quality of Life , Cross-Sectional Studies , Hodgkin Disease/therapy , Surveys and QuestionnairesABSTRACT
Probiotics are live microorganisms that confer health benefits to their animal host by balancing the composition of its gastrointestinal microbiota and modulating its immune response. In this work, we studied bacterial consortia isolated from the rumen of 28- and 42-day-old calves to select those showing probiotic capacity. Consortia were characterized and their growth dynamics were determined in several growth media. The number of viable bacteria was larger in the Man, Rogosa and Sharpe broth (MRS) than in nutritive medium A (MNA) and the largest was for A3D42. Antibiotic susceptibility of bacterial consortia in MRS was higher than in MNA and the most susceptible samples were A1D28 and A3D42. In turn, A3D42 showed the highest tolerance to bile salts in MRS and MNA. Moreover, all bacterial consortia showed optimal growth at pH 5, 5.5, 6 and 7 in both media, while their temperature tolerance was higher in MRS. The antagonistic activity of bacterial consortia in MNA was higher than in MRS with A2D42 showing the best antagonistic activity for Pseudomona aureginosa (ATCC 9027) and Staphylococcus aureus (ATCC 6538) in MNA. Additionally, A1D42 and A2D42 in MRS and A3D42 in MNA had significant adhesion to mucins, and A1D42 in MRS had the highest. Regarding their species composition, all bacterial consortia in MRS belonged to the phylum Firmicutes, and the class Bacilli and bacterial consortia in MNA belonged to three phyla; Proteobacteria, Firmicutes, and Bacteroidetes. Lactobacillus casei, Lactobacillus rhamnosus, Lactobacillus fermentum, and Lactobacillus johnsonii were identified in all bacterial consortia in MRS broth. Based on these results, A1D42 and A3D42 grown in MRS showed the best potential as probiotics for calves, which could result in health benefits and improve their production.