Heterogeneous Pathways Research Articles

Microscopic Mechanism for Further NO Heterogeneous Reduction by Potassium-Doped Biochar: A DFT Study.

Biomass reburning is an efficient and low-cost way to control nitric oxide (NO), and the abundant potassium (K) element in biomass affects the heterogeneous reaction between NO and biochar. Due to the incomplete simulation of the NO heterogeneous reduction reaction pathway at the molecular level and the unclear catalytic effect of K element in biochar, further research is needed on the possible next reaction and the influencing mechanism of the element. After the products of the existing reaction pathways are referenced, two reasonably simplified biochar structural models are selected as the basic reactants to study the microscopic mechanism for further NO heterogeneous reduction on the biochar surface before and after doping with the K atom based on density functional theory. In studying the two further NO heterogeneous reduction reaction pathways, we find that the carbon monoxide (CO) molecule fragment protrudes from the surface of biochar models with the desorption of N2 at the TS4 transition state, and the two edge types of biochar product models obtained by simulation calculation are Klein edge and ac56 edge observed in the experiment. In studying the catalytic effect of potassium in biochar, we find that the presence of K increases the heat release of adsorption of NO molecules, reduces the energy barrier of the rate-determining step in the nitrogen (N2) generation and desorption process (by 50.88 and 69.97%), and hinders the CO molecule from desorbing from the biochar model surface. Thermodynamic and kinetic analyses also confirm its influence. The study proves that the heterogeneous reduction reaction of four NO molecules on the surface of biochar completes the whole reaction process and provides a basic theoretical basis for the emission of nitrogen oxides (NOx) during biomass reburning.

Modified nano magnetic Fe2O3-MgO as a high active multifunctional heterogeneous catalyst for environmentally beneficial carbon–carbon synthesis

In this study, novel nanomagnetic catalysts, namely Fe2O3-MgO@choline formate (Ch. F.) and Fe2O3-MgO@choline cyanide (Ch. CN), were synthesized through immobilizing choline-based ion liquids to magnetic support via a simple and cost-effective methodology. FT-IR, TGA, FE-SEM, VSM, EDS, BET, and XRD techniques were employed to assess and characterize these organic–inorganic compounds. Following the successful preparation of nanoparticles, the catalysts were utilized in Knoevenagel and benzoin condensations. Fe2O3-MgO@Ch.F. exhibited exceptional activity in Knoevenagel condensation under solvent-free conditions at room temperature, achieving high yields (91–98%) in a short timeframe. Similarly, Fe2O3-MgO@Ch.CN demonstrated remarkable activity in benzoin condensation under environmentally friendly solvent conditions, yielding higher isolated yields (76–88%). Furthermore, these magnetically recyclable multifunctional catalysts displayed the ability to be reused up to five times without a significant loss in efficiency. Additionally, the heterogeneity of this nanocatalyst was investigated using the hot filtration technique. The findings indicated that the reaction primarily occurs via a heterogeneous pathway.

Periodate activation by MnFe2O4 spinel for sulfamethoxazole degradation: Iodate radical dominance, degradation pathway, DFT calculation and toxicity assessment

This study synthesized spinel MnFe2O4 at different temperatures, which was applied to activate periodate (PI) for sulfamethoxazole (SMX) degradation. It was found that the 500-MFO (MnFe2O4 calcined at 500 ℃) demonstrated superior activity in PI activation, with notable sustainability but strong substrate selectivity. Furthermore, a comprehensive analysis, including quenching experiment, electron paramagnetic resonance (EPR) technique, X-ray photoelectron spectroscopy (XPS) analysis, metal ions leaching detection, homogeneous PI activation, and methyl phenyl sulfoxide (PMSO) probe test, revealed that homo- and heterogeneous pathways as well as free and non-free radical routes coexisted in the 500-MFO/PI system. Multiple active species, including iodate radical (IO3•), hydroxyl radical (•OH), superoxide radical (O2•-), singlet oxygen (1O2), and Mn(IV) were identified, with IO3• from heterogeneous activation being the primary species. When PMSO and SMX coexisted, PMSO could react with Mn(IV), promoting the regeneration of Mn reaction sites and the production of IO3•, thereby being beneficial for the degradation of SMX. The degradation pathways of SMX were elucidated through high-performance liquid chromatography-mass spectrometry (HPLC-MS) and density functional theory (DFT) calculation. The acute and chronic toxicity of thirteen by-products to aquatic organisms were predicted using the Ecological Structure Activity Relationships (ECOSAR) software, with the corresponding results revealing that although the toxicity of intermediates fluctuated, the final products were environmentally benign. Therefore, this investigation provides a viable method for SMX degradation in wastewater treatment.

Unlocking glycerol monolaurate potential: A comprehensive review of synthesis pathways, catalyst insights, and optimization strategies

Glycerol monolaurate (GML) is a versatile green chemical with wide industrial applicability, including in the food, pharmaceutical, and personal care product industries. This review provides a thorough analysis of the processes involved in GML production, along with the diverse applications of GML. And also, addresses various limitations and challenges associated with esterification of lauric acid with glycerol to produce GML through enzymatic, homogeneous, and heterogeneous catalytic pathways. Among these routes, heterogeneous catalytic routes exhibited superior catalytic activity, achieving over 90% selectivity with good stability. Furthermore, the review offers a constructive assessment of the process parameters associated with catalysts and reaction conditions that influence the GML yield and selectivity. Notably, wide pore and short pore length were found to be suitable for attaining higher selectivity in esterification of lauric acid. Techno-economic assessments suggest that the enzyme route is more environmentally sustainable. However, in practice, the heterogeneous catalytic route proves more suitable for industrial-scale production. Therefore, this review may provide crucial guidance for researchers and industries aiming to produce GML in an economic and eco- friendly manner.

Revealing the Contribution of Interfacial Processes to Atmospheric Oxidizing Capacity in Haze Chemistry.

The atmospheric oxidizing capacity is the most important driving force for the chemical transformation of pollutants in the atmosphere. Traditionally, the atmospheric oxidizing capacity mainly depends on the concentration of O3 and other gaseous oxidants. However, the atmospheric oxidizing capacity based on gas-phase oxidation cannot accurately describe the explosive growth of secondary particulate matter under complex air pollution. From the chemical perspective, the atmospheric oxidizing capacity mainly comes from the activation of O2, which can be achieved in both gas-phase and interfacial processes. In the heterogeneous or multiphase formation pathways of secondary particulate matter, the enhancement of oxidizing capacity ascribed to the O2/H2O-involved interfacial oxidation and hydrolysis processes is an unrecognized source of atmospheric oxidizing capacity. Revealing the enhanced oxidizing capacity due to interfacial processes in high-concentration particulate matter environments and its contribution to the formation of secondary pollution are critical in understanding haze chemistry. The accurate evaluation of atmospheric oxidizing capacity ascribed to interfacial processes is also an important scientific basis for the implementation of PM2.5 and O3 collaborative control in China and around the world.

Direct aqueous photochemistry of methylglyoxal and its effect on sulfate formation

In recent years, among many oxidation pathways studied for atmospheric sulfate formation, the aqueous phase oxidation pathways of H2O2 and organic hydroperoxides (ROOHs) have attracted great scientific attention. Higher concentrations of H2O2 and ubiquitous ROOHs have been observed in atmospheric aqueous phase environments (cloud water, fog droplets, etc.). However, there are still some gaps in the study of their aqueous phase generation and their influences on sulfate formation. In this study, the aqueous phase photochemical reaction of methylglyoxal, a ubiquitous organic substance in the atmospheric aqueous phase, was studied under UV irradiation, and the generation of H2O2 and ROOHs in this system was investigated. It is found for the first time that the aqueous phase photolysis of methylglyoxal not only produces H2O2 but also produces ROOHs, and UV light and O2 are necessary for the formation of H2O2 and ROOHs. Based on the experimental results, the possible mechanism of aqueous phase photochemistry of methylglyoxal and the generation of H2O2 and ROOHs were proposed. The effect of aqueous phase photolysis of methylglyoxal on sulfate formation under different conditions was also investigated. The results show that the aqueous phase photolysis of methylglyoxal significantly promoted SO2 oxidation and sulfate formation, in which SO2 oxidation was realized by the generated H2O2, ROOHs and •OH radicals, and the importance of the formed ROOHs cannot be ignored. These results fill some gaps in the field of aqueous phase H2O2 and ROOHs production, and to a certain extent confirm the important roles of the aqueous phase photolysis of methylglyoxal and the formed H2O2 and ROOHs in the production of sulfate. The study reveals the new sources of H2O2 and ROOHs, and provides a new insight into the heterogeneous aqueous phase oxidation pathways and mechanisms of SO2 in cloud and fog droplets and haze particles.

Evaluation of dust and gas explosion potential in chemical looping processes

The explosibility of metals typically used as oxygen carriers in chemical looping processes are reviewed. Chemical looping processes use intensified process conditions such as elevated temperatures and pressures to accelerate reduction and oxidation reactions of metals. A review of literature on metals indicates they are generally non-explosible under standard test conditions, however, at conditions used in chemical looping processes the opportunity to remove kinetic limitations exists resulting in reclassification of these dusts as marginally explosible under these circumstances. Potential locations and scenarios for explosions involving oxygen carriers in chemical looping processes are described. Operating conditions (temperature, pressure) and oxygen carrier qualities (base metal, support/loading) are reviewed for their effect on explosion severity parameters. These studies show explosions are unlikely to be severe in chemical looping reactors, but severity can increase while likelihood decreases in windboxes and in downstream process units following cooling. The potential for explosions where a metal oxide dust acts as the oxidizing agent for gaseous fuels through heterogeneous (chemical looping combustion – CLC) and homogenous (chemical looping oxygen uncoupling – CLOU) pathways as may be found in chemical looping processes is introduced, which we term a metal oxide reducing environment (MORE) explosion. Methane was shown to have the potential for the most serious consequences when reacting with copper- and manganese-oxides due to their reduction both being exothermic and increasing the quantity of gas present. Hematite and nickel oxide do not demonstrate this behaviour with common gaseous fuels. Potential prevention and mitigation strategies for explosions in chemical looping processes are briefly introduced. Particulate management strategies, venting, and downstream concerns are discussed.

Single Droplet Tweezer Revealing the Reaction Mechanism of Mn(II)-Catalyzed SO2 Oxidation.

Sulfate aerosol is one of the major components of secondary fine particulate matter in urban haze that has crucial impacts on the social economy and public health. Among the atmospheric sulfate sources, Mn(II)-catalyzed SO2 oxidation on aerosol surfaces has been regarded as a dominating one. In this work, we measured the reaction kinetics of Mn(II)-catalyzed SO2 oxidation in single droplets using an aerosol optical tweezer. We show that the SO2 oxidation occurs at the Mn(II)-active sites on the aerosol surface, per a piecewise kinetic formulation, one that is characterized by a threshold surface Mn(II) concentration and gaseous SO2 concentration. When the surface Mn(II) concentration is lower than the threshold value, the reaction rate is first order with respect to both Mn(II) and SO2, agreeing with our traditional knowledge. But when surface Mn(II) concentration is above the threshold, the reaction rate becomes independent of Mn(II) concentration, and the reaction order with respect to SO2 becomes greater than unity. The measured reaction rate can serve as a tool to estimate sulfate formation based on field observation, and our established parametrization corrects these calculations. This framework for reaction kinetics and parametrization holds promising potential for generalization to various heterogeneous reaction pathways.

Heterogeneous ERBB gene pathways, their targeted treatment and possible molecular mechanisms of resistance in metastatic gallbladder cancer

BackgroundERBB amplifications and mutations are known in metastatic gallbladder cancer (GBC). We conducted a prospective study on targeted therapy based on comprehensive genomic profiling (CGP). We report molecular pathways of ERBB gene and outcomes and explored the molecular mechanism of resistance. MethodsCGP was done for all consecutive GBC patients aged >18 years. Foundation medicines CDx and TarGT Absolute were used for analysis. Patients were enrolled from Jan 2017 till Dec 2022. Patient recruitment was done after ethics committee approval. Trastuzumab and/ or lapatinib were used as targeted therapy. ResultsTwenty-six patients out of 60 had ERBB1-4 gene alteration (amplification and/or mutation) that resulted in activation of PI3K/AKT/MTOR and RAS/RAF/MEK pathways. ERBB amplification (16%) was the most common genetic aberration. Mutations in TP53, RB1, CDKs, and cyclins lead to dysregulation of cell cycle and evasion of apoptosis. A total of 50% of ERBB2-positive patients carry CDK12 amplifications. The intrinsic resistance to anti-ERBB2 therapy was primarily due to downstream activation in ERBB pathway (PIK3CA) and its crosstalk with cell cycle pathway (TP53 and CDK12), JAK/STAT, VEGF, CTNNB1, and ARID1A that are known to drive MAPK/ERK signaling. Mesenchymal epithelial transition amplification or activating mutations is mechanism of resistance to anti-ERBB2 therapy. Kinase/Juxta membrane domain mutations in ERBB family proteins are also one of the potential mechanisms of resistance. ConclusionGBC is enriched with ERBB gene aberrations. Targeted therapy of ERBB pathway has shown encouraging responses. CDK12 gene amplification is a possible mechanism of resistance identified.

SEMORE: SEgmentation and MORphological fingErprinting by machine learning automates super-resolution data analysis

The morphology of protein assemblies impacts their behaviour and contributes to beneficial and aberrant cellular responses. While single-molecule localization microscopy provides the required spatial resolution to investigate these assemblies, the lack of universal robust analytical tools to extract and quantify underlying structures limits this powerful technique. Here we present SEMORE, a semi-automatic machine learning framework for universal, system- and input-dependent, analysis of super-resolution data. SEMORE implements a multi-layered density-based clustering module to dissect biological assemblies and a morphology fingerprinting module for quantification by multiple geometric and kinetics-based descriptors. We demonstrate SEMORE on simulations and diverse raw super-resolution data: time-resolved insulin aggregates, and published data of dSTORM imaging of nuclear pore complexes, fibroblast growth receptor 1, sptPALM of Syntaxin 1a and dynamic live-cell PALM of ryanodine receptors. SEMORE extracts and quantifies all protein assemblies, their temporal morphology evolution and provides quantitative insights, e.g. classification of heterogeneous insulin aggregation pathways and NPC geometry in minutes. SEMORE is a general analysis platform for super-resolution data, and being a time-aware framework can also support the rise of 4D super-resolution data.

MicroRNA-guided drug discovery for mitigating persistent pulmonary complications in critical COVID-19 survivors: A longitudinal pilot study.

The post-acute sequelae of SARS-CoV-2 infection pose a significant global challenge, with nearly 50% of critical COVID-19 survivors manifesting persistent lung abnormalities. The lack of understanding about the molecular mechanisms and effective treatments hampers their management. Here, we employed microRNA (miRNA) profiling to decipher the systemic molecular underpinnings of the persistent pulmonary complications. We conducted a longitudinal investigation including 119 critical COVID-19 survivors. A comprehensive pulmonary evaluation was performed in the short-term (median = 94.0days after hospital discharge) and long-term (median = 358 days after hospital discharge). Plasma miRNAs were quantified at the short-term evaluation using the gold-standard technique, RT-qPCR. The analyses combined machine learning feature selection techniques with bioinformatic investigations. Two additional datasets were incorporated for validation. In the short-term, 84% of the survivors exhibited impaired lung diffusion (DLCO < 80% of predicted). One year post-discharge, 54.4% of this patient subgroup still presented abnormal DLCO . Four feature selection methods identified two specific miRNAs, miR-9-5p and miR-486-5p, linked to persistent lung dysfunction. The downstream experimentally validated targetome included 1473 genes, with heterogeneous enriched pathways associated with inflammation, angiogenesis and cell senescence. Validation studies using RNA-sequencing and proteomic datasets emphasized the pivotal roles of cell migration and tissue repair in persistent lung dysfunction. The repositioning potential of the miRNA targets was limited. Our study reveals early mechanistic pathways contributing to persistent lung dysfunction in critical COVID-19 survivors, offering a promising approach for the development of targeted disease-modifying agents.

Distinct uptake and elimination profiles for trastuzumab, human IgG, and biocytin-TMR in experimental HER2+ brain metastases of breast cancer.

The aim of this study is an improved understanding of drug distribution in brain metastases. Rather than single point snapshots, we analyzed the time course and route of drug/probe elimination (clearance), focusing on the intramural periarterial drainage (IPAD) pathway. Mice with JIMT1-BR HER2+ experimental brain metastases were injected with biocytin-TMR and either trastuzumab or human IgG. Drugs/probes circulated for 5 min to 48 h, followed by perfusion. Brain sections were stained for human IgG, vascular basement membrane proteins laminin or collagen IV, and periarterial α-SMA. A machine learning algorithm was developed to identify metastases, metastatic microenvironment, and uninvolved brain in confocally scanned brain sections. Drug/probe intensity over time and total imaged drug exposure (iAUC) were calculated for 27,249 lesions and co-immunofluorescence with IPAD-vascular matrix analyzed in 11,668 metastases. In metastases, peak trastuzumab levels were 5-fold higher than human IgG but 4-fold less than biocytin-TMR. The elimination phase constituted 85-93% of total iAUC for all drugs/probes tested. For trastuzumab, total iAUC during uptake was similar to the small molecule drug probe biocytin-TMR, but slower trastuzumab elimination resulted in a 1.7-fold higher total iAUC. During elimination trastuzumab and IgG were preferentially enriched in the α-SMA+ periarterial vascular matrix, consistent with the IPAD clearance route; biocytin-TMR showed heterogeneous elimination pathways. Drug/probe elimination is an important component of drug development for brain metastases. We identified a prolonged elimination pathway for systemically administered antibodies through the periarterial vascular matrix that may contribute to the sustained presence and efficacy of large antibody therapeutics.

Abstract A107: MAPK signaling is a conserved mechanism explaining phenotypic heterogeneity across diverse drivers of epithelial-mesenchymal transition in pancreas cancer

Abstract Epithelial-mesenchymal transition (EMT) is a developmental process that is aberrantly activated in cancers such as pancreatic ductal adenocarcinoma (PDAC) to promote disease progression and chemoresistance. EMT occurs heterogeneously among PDAC ductal cells, which frustrates efforts to identify the underlying signaling regulatory mechanisms. We hypothesize that cell-to-cell variation in the activities of specific signaling pathways explains EMT heterogeneity. To test this, we developed a workflow integrating: 1) iterative indirect immunofluorescence imaging (4i) to quantify the activities of up to seven purported EMT-regulating pathways with single-cell resolution and 2) a multivariate mutual information computational model to predict the pathways that are most informative of the EMT phenotype. In cultured PDAC cells, EMT was induced by treating cells with growth factors present in the tumor microenvironment (hepatocyte growth factor, epidermal growth factor, transforming growth factor β1, or two combinations) or with chemotherapeutics (gemcitabine or 5-fluorouracil). EMT phenotypic markers and signaling pathway proxies were assessed daily for up to 96 hr. A mutual information analysis of the aggregated data identified ERK as the most important signaling node explaining EMT heterogeneity across the diverse set of agonists investigated. Kinase inhibition and siRNA studies confirmed the implied role of ERK but also revealed a compensatory, EMT-driving JNK activation in the context of MEK inhibition that explains a cooperative effect of simultaneous MEK and JNK inhibition on EMT antagonism. Importantly, a model based on cell population-level measurements nominated JNK as more informative than ERK for determining EMT state in response to growth factors. We are implementing this approach in vivo using pancreas cancer tissue sections to determine generalizability of these findings in different microenvironmental contexts. Overall, our results demonstrate the pervasive importance of ERK for diverse drivers of EMT and the need to account for the effects of heterogeneous signaling pathway activation in the determination of EMT. Citation Format: Michelle C. Barbeau, Matthew J. Lazzara. MAPK signaling is a conserved mechanism explaining phenotypic heterogeneity across diverse drivers of epithelial-mesenchymal transition in pancreas cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Pancreatic Cancer; 2023 Sep 27-30; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(2 Suppl):Abstract nr A107.

Engineered acetogenic bacteria as microbial cell factory for diversified biochemicals.

Acetogenic bacteria (acetogens) are a class of microorganisms with conserved Wood-Ljungdahl pathway that can utilize CO and CO2/H2 as carbon source for autotrophic growth and convert these substrates to acetate and ethanol. Acetogens have great potential for the sustainable production of biofuels and bulk biochemicals using C1 gases (CO and CO2) from industrial syngas and waste gases, which play an important role in achieving carbon neutrality. In recent years, with the development and improvement of gene editing methods, the metabolic engineering of acetogens is making rapid progress. With introduction of heterogeneous metabolic pathways, acetogens can improve the production capacity of native products or obtain the ability to synthesize non-native products. This paper reviews the recent application of metabolic engineering in acetogens. In addition, the challenges of metabolic engineering in acetogens are indicated, and strategies to address these challenges are also discussed.

Morphine- and foot shock-responsive neuronal ensembles in the VTA possess different connectivity and biased GPCR signaling pathway.

Background: Neurons in the ventral tegmental area (VTA) are sensitive to stress and their maladaptation have been implicated in the psychiatric disorders such as anxiety and addiction, etc. The cellular properties of the VTA neurons in response to different stressors related to different emotional processing remain to be investigated. Methods: By combining immediate early gene (IEG)-dependent labeling, rabies virus tracing, ensemble-specific transcriptomic analysis and fiber photometry recording in the VTA of male mice, the spatial distribution, brain-wide connectivity and cellular signaling pathways in the VTA neuronal ensembles in response to morphine (Mor-Ens) or foot shock (Shock-Ens) stimuli were investigated. Results: Optogenetic activation of the Mor-Ens drove approach behavior, whereas chemogenetic activation of the Shock-Ens increased the anxiety level in mice. Mor-Ens were clustered and enriched in the ventral VTA, contained a higher proportion of dopaminergic neurons, received more inputs from the dorsal medial striatum and the medial hypothalamic zone, and exhibited greater axonal arborization in the zona incerta and ventral pallidum. Whereas Shock-Ens were more dispersed, contained a higher proportion of GABAergic neurons, and received more inputs from the ventral pallidum and the lateral hypothalamic area. The downstream targets of the G protein and β-arrestin pathways, PLCβ3 and phosphorylated AKT1Thr308, were relatively enriched in the Mor-Ens and Shock-Ens, respectively. Cariprazine, the G-protein-biased agonist for the dopamine D2 receptor, increased the response of Mor-Ens to sucrose water and decreased the anxiety-like behavior during morphine withdrawal, whereas the β-arrestin-biased agonist UNC9994 decreased the response of Shock-Ens to tail suspension. Conclusions: Taken together, these findings reveal the heterogeneous connectivity and signaling pathways of the VTA neurons in response to morphine and foot shock, providing new insights for development of specific interventions for psychiatric disorders caused by various stressors associated with different VTA neuronal functions.

From Development to Place in Therapy of Lorlatinib for the Treatment of ALK and ROS1 Rearranged Non-Small Cell Lung Cancer (NSCLC).

Following the results of the CROWN phase III trial, the third-generation macrocyclic ALK inhibitor lorlatinib has been introduced as a salvage option after the failure of a first-line TKI in ALK-rearranged NSCLC, while its precise role in the therapeutic algorithm of ROS1 positive disease is still to be completely defined. The ability to overcome acquired resistance to prior generation TKIs (alectinib, brigatinib, ceritinib, and crizotinib) and the high intracranial activity in brain metastatic disease thanks to increased blood-brain barrier penetration are the reasons for the growing popularity and interest in this molecule. Nevertheless, the major vulnerability of this drug resides in a peculiar profile of related collateral events, with neurological impairment being the most conflicting and debated clinical issue. The cognitive safety concern, the susceptibility to heterogeneous resistance pathways, and the absence of a valid alternative in the second line are strongly jeopardizing a potential paradigm shift in this oncogene-addicted disease. So, when prescribing lorlatinib, clinicians must face two diametrically opposed characteristics: a great therapeutic potential without the intrinsic limitations of its precursor TKIs, a cytotoxic activity threatened by suboptimal tolerability, and the unavoidable onset of resistance mechanisms we cannot properly manage yet. In this paper, we give a critical point of view on the stepwise introduction of this promising drug into clinical practice, starting from its innovative molecular and biochemical properties to intriguing future developments, without forgetting its weaknesses.

RETIREMENT TRAJECTORIES AND HEALTH IN JAPAN

Abstract The relationship between retirement and health is a key issue in aging societies. However, it is unclear whether the nature of retirement from full-time regular employment makes a difference in subsequent health. This study examines the relationship between the trajectory of retirement from full-time regular employment and subsequent health. Using the Longitudinal Survey of Middle-aged and Elderly Persons 2005–2019 collected in Japan, we employ sequence analysis to identify distinct retirement trajectories from full-time regular employment between ages 59 and 66. We then estimate the causal relationship between retirement trajectories and health using instrumental variable methods. Sequence analysis classifies the retirement trajectories into four groups: gradual retirement, abrupt retirement, continued non-standard employment, and continued regular employment. Instrumental variable estimation shows no statistically significant differences in the effects of these retirement trajectories on health, but suggests that gradual retirement may be more beneficial to health than other three retirement trajectories. Several robustness checks also show no statistical difference in the effect of retirement trajectories on health. These findings provide an empirical foundation for understanding the possible implications of heterogenous retirement pathways for health in later life and labor market policies in very old populations.

Abstract C051: Alteration of protein translation by eIF4A1 inhibition exquisitely primes lymphoma cells to induction of ferroptosis

Abstract Background: Ferroptosis induction as a cancer therapy faces challenges establishing clinical therapeutic windows. Cells employ diverse mechanisms to prevent iron-mediated oxidation of membrane polyunsaturated fatty acids that causes ferroptosis, but populations with low rates of protein synthesis such as hematopoietic stem cells are more susceptible. Therefore, we hypothesized protein synthesis inhibitors might enhance therapeutic ferroptosis induction. Rocaglates, inhibitors targeting eIF4A1, have entered clinical trials with promising potential against diffuse large B-cell lymphoma (DLBCL), which also exhibits pre-clinical susceptibility to ferroptosis induction. Up to 40% of patients with DLBCL, the most common lymphoma type, have poor outcomes requiring new approaches to address these persistent unmet clinical needs. Our results reveal striking synergy of rocaglates, including the clinical compound zotatifin (eFT226), with ferroptosis inducers. TMT-pSILAC and RNA-seq analyses revealed profound deregulation of ferroptotic protection resulting from rocalate effects on protein synthesis. Methods: We used RNA-seq and TMT-pSILAC followed by mass spectrometry to analyze transcriptome and protein output in SU-DHL-10 DLBCL cells treated with zotatifin or DMSO for 24h. Enrichment analyses (Enrichr platform, ChIP-X Enrichment Analysis 3, GSEA) identified differentially expressed genes, proteins and transcription factors. We explored synergy between zotatifin and ferroptosis modulators in DLBCL cell lines and measured a wide variety of associated cellular endpoints including lipid peroxidation, glutathione levels, and glutathione peroxidase 4 (GPX4) expression. Results: TMT-pSILAC translatome assessment during rocaglate exposure revealed expression alteration(log2FC ≥ 1.5) of numerous key proteins involved in oxidative stress (i.e. SDHB, SDHA, TRAP1, SCO1, UQCRH, ETFA, COX7C) and enrichment of factors indicating induction of an antioxidant response (CD98HC, NRF1, ATF2, SP2, and NFE2L). These changes led to high synergy of zotatifin in combination with a wide variety of ferroptosis inducers (Bliss δ synergy score &amp;gt; 10) and antagonism with ferroptosis inhibitors (Bliss δ synergy score &amp;lt; - 10). These results were consistent across multiple DLBCL mouse and human experimental systems, and preliminarily appear present also in models of T-cell lymphomas. Lipid peroxidation levels were significantly enhanced when zotatifin was combined with erastin (p-value &amp;lt; 0.0005). Moreover, zotatifin treatment resulted in elevated levels of reduced glutathione (GSH), an effect overcome by addition of ferroptosis inducers (p-value &amp;lt; 0.005). Consistently, GPX4 expression was also impaired. Conclusions: Rocaglates induce novel alterations in oxidative stress factors and associated response pathways, sensitizing B and T lymphomas to therapeutic ferroptosis induction. These findings provide valuable insights for using rocaglates in combination with ferroptosis induction to overcome heterogeneous resistance pathways in high-risk lymphoma patients. Citation Format: Paola Manara, Alexa Marie Barroso, Abdessamad Youssfi Alaoui, Olivia Barbara Lightfuss, Tyler Andrew Cunningham, Kyle Hoffman, Caroline Alice Coughlin, Jonathan Harry Schatz. Alteration of protein translation by eIF4A1 inhibition exquisitely primes lymphoma cells to induction of ferroptosis [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr C051.

PP20 Vaccines market access pathways in Asia-Pacific (APAC) – analysis and recommendations for improvement

IntroductionImmunization is one of the most effective public health interventions, saving millions of lives annually. However, complex and heterogenous market access pathways can impact timely and equitable population access to vaccines. Focusing on five Asia-Pacific (APAC) countries, this study described the current vaccine market access landscape and analyzed the success factors for National Immunization Program (NIP) inclusion.MethodsThe study was conducted in two phases (i) pragmatic literature review to map current regulatory and funding pathways and identify information gaps in China, Japan, Korea, Taiwan and Australia (ii) targeted interviews with market access and policy experts in each market to identify drivers and barriers to NIP inclusion.ResultsRegulatory approval, driven by safety and efficacy data, followed by introduction in the private market was commonly observed in all markets. However, pathways to NIP inclusion varied within and between markets. In all markets expert panels such as National Immunization Technical Advisory Groups (NITAG) were identified to play a crucial role in providing advice to governments on NIP inclusion. Health technology assessment was increasingly used to inform decision making. However, the assessment frameworks utilized were typically designed for medicines, rather than the unique features of vaccines.Japan, Korea and Australia provided relatively consistent coverage via national programs, despite the different processes employed to review, recommend and reimburse vaccines. In some cases, the reimbursement timeframe varied significantly for different vaccines within the same market. China and Taiwan provided coverage at the regional level, which required engagement with multiple local authorities to enable access. The key barriers to patient access were budget limitations, long reimbursement timeframes and a lack of coverage consistency. Early stakeholder engagement, local epidemiology and cost-effectiveness evidence were the main success factors for NIP inclusion.ConclusionsFunding pathways for vaccines in APAC are heterogenous. Adopting the Asia-Pacific Economic Cooperation (APEC) Action Plan on Vaccination Across the Life Course could increase vaccine coverage through alignment, collaboration, and improvement of reimbursement pathways in APAC.

Reevaluating progression and pathways following Mycobacterium tuberculosis infection within the spectrum of tuberculosis.

Traditional understanding of the risk of progression from Mycobacterium tuberculosis (Mtb) infection to tuberculosis (TB) overlooks diverse presentations across a spectrum of disease. We developed a deterministic model of Mtb infection and minimal (pathological damage but not infectious), subclinical (infectious but no reported symptoms), and clinical (infectious and symptomatic) TB, informed by a rigorous evaluation of data from a systematic review of TB natural history. Using a Bayesian approach, we calibrated the model to data from historical cohorts that followed tuberculin-negative individuals to tuberculin conversion and TB, as well as data from cohorts that followed progression and regression between disease states, disease state prevalence ratios, disease duration, and mortality. We estimated incidence, pathways, and 10-y outcomes following Mtb infection for a simulated cohort. Then, 92.0% (95% uncertainty interval, UI, 91.4 to 92.5) of individuals self-cleared within 10 y of infection, while 7.9% (95% UI 7.4 to 8.5) progressed to TB. Of those, 68.6% (95% UI 65.4 to 72.0) developed infectious disease, and 33.2% (95% UI 29.9 to 36.4) progressed to clinical disease. While 98% of progression to minimal disease occurred within 2 y of infection, only 71% and 44% of subclinical and clinical disease, respectively, occurred within this period. Multiple progression pathways from infection were necessary to calibrate the model and 49.5% (95% UI 45.6 to 53.7) of those who developed infectious disease undulated between disease states. We identified heterogeneous pathways across disease states after Mtb infection, highlighting the need for clearly defined disease thresholds to inform more effective prevention and treatment efforts to end TB.