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1.
Blood Adv ; 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38991126

RESUMEN

Underrepresentation of racial and ethnic subgroups in cancer clinical trials remains a persistent challenge. Restrictive clinical trial eligibility criteria have been shown to exacerbate this problem. We previously identified that up to 24% of patients treated with standard immunochemotherapy (IC) would have been excluded from recent first-line trials in diffuse large B-cell lymphoma (DLBCL) based on 5 lab-based criteria. These ineligible patients had worse clinical outcomes and increased deaths related to lymphoma progression suggesting the potential exclusion of patients who could have benefited most from the novel therapies being evaluated. Utilizing data from the prospectively enrolled Lymphoma Epidemiology Outcomes (LEO) Cohort study, with demographics broadly similar to the U.S. patients diagnosed with lymphoma, we evaluated the impact of laboratory eligibility criteria from recent first-line DLBCL trials across various racial and ethnic backgrounds. There were significant differences in the baseline lab values by race/ethnicity with Black/African American (AA) patients having the lowest mean hemoglobin and highest creatinine clearance. Based on recent clinical trial eligibility criteria, AA and Hispanic patients had higher rates of lab-based ineligibility compared to Non-Hispanic Whites. The largest gap in the clinical outcomes between eligible (ref) and non-eligible patients was noted within AA patients with an overall survival hazard ratio based on POLARIX clinical trial criteria of 4.09, 95% CI: 1.83-9.14. A thoughtful approach to the utility of each criterion and cut offs for eligibility needs to be evaluated in the context of its differential impact across various racial/ethnic groups.

2.
Blood Adv ; 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38991123

RESUMEN

A phase 2, international, open-label, non-randomized, single-arm trial was conducted to evaluate the efficacy and safety of tipifarnib, a farnesyltransferase inhibitor, as monotherapy for relapsed/refractory peripheral T-cell lymphoma (PTCL) and to evaluate tumor mutation profile as a biomarker of response. Adults with relapsed/refractory PTCL received tipifarnib 300 mg orally twice daily for 21 days in a 28-day cycle. The primary endpoint was objective response rate (ORR); secondary endpoints included ORR, progression-free survival (PFS), duration of response (DOR), and adverse events (AEs) in specific subtypes. Sixty-five patients with PTCL were enrolled: n=38 angioimmunoblastic T-cell lymphoma (AITL), n=25 PTCL not otherwise specified (PTCL-NOS), and n=2 other T-cell lymphomas. The ORR was 39.7% (95% CI, 28.1-52.5) in all patients and 56.3% (95% CI, 39.3-71.8) for AITL. Median PFS was 3.5 months overall (954% CI, 2.1-4.4), and 3.6 months (95% CI, 1.9-8.3) for AITL. Median DOR was 3.7 months (95% CI, 2.0-15.3), and greatest in AITL patients (7.8 months; 95% CI, 2.0-16.3). The median overall survival was 32.8 months (95% CI, 14.4 to not applicable). Tipifarnib-related hematologic AEs were manageable and included: neutropenia (43.1%), thrombocytopenia (36.9%), and anemia (30.8%); other tipifarnib-related AEs included nausea (29.2%) and diarrhea (27.7%). One treatment-related death occurred. Mutations in RhoA, DNMT3A, and IDH2 were seen in 60%, 33%, and 27%, respectively, in the AITL tipifarnib responder group vs 36%, 9%, and 9% in the non-responder group. Tipifarnib monotherapy demonstrated encouraging clinical activity in heavily pre-treated relapsed/refractory PTCL, especially in AITL, with a manageable safety profile. ClinicalTrials.gov NCT02464228.

3.
Nat Struct Mol Biol ; 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38987455

RESUMEN

Protein folding in vivo begins during synthesis on the ribosome and is modulated by molecular chaperones that engage the nascent polypeptide. How these features of protein biogenesis influence the maturation pathway of nascent proteins is incompletely understood. Here, we use hydrogen-deuterium exchange mass spectrometry to define, at peptide resolution, the cotranslational chaperone-assisted folding pathway of Escherichia coli dihydrofolate reductase. The nascent polypeptide folds along an unanticipated pathway through structured intermediates not populated during refolding from denaturant. Association with the ribosome allows these intermediates to form, as otherwise destabilizing carboxy-terminal sequences remain confined in the ribosome exit tunnel. Trigger factor binds partially folded states without disrupting their structure, and the nascent chain is poised to complete folding immediately upon emergence of the C terminus from the exit tunnel. By mapping interactions between the nascent chain and ribosomal proteins, we trace the path of the emerging polypeptide during synthesis. Our work reveals new mechanisms by which cellular factors shape the conformational search for the native state.

4.
Evol Ecol ; 38(3): 387-397, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38946730

RESUMEN

Animal and plant colouration presents a striking dimension of phenotypic variation, the study of which has driven general advances in ecology, evolution, and animal behaviour. Quantitative Colour Pattern Analysis (QCPA) is a dynamic framework for analysing colour patterns through the eyes of non-human observers. However, its extensive array of user-defined image processing and analysis tools means image analysis is often time-consuming. This hinders the full use of analytical power provided by QCPA and its application to large datasets. Here, we offer a robust and comprehensive batch script, allowing users to automate many QCPA workflows. We also provide a complimentary set of useful R scripts for downstream data extraction and analysis. The presented batch processing extension will empower users to further utilise the analytical power of QCPA and facilitate the development of customised semi-automated workflows. Such quantitatively scaled workflows are crucial for exploring colour pattern spaces and developing ever-richer frameworks for analysing organismal colouration accounting for visual perception in animals other than humans. These advances will, in turn, facilitate testing hypotheses on the function and evolution of vision and signals at quantitative and qualitative scales, which are otherwise computationally unfeasible. Supplementary Information: The online version contains supplementary material available at 10.1007/s10682-024-10291-7.

5.
Sci Adv ; 10(27): eado5979, 2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38959303

RESUMEN

Programmable self-assembly has seen an explosion in the diversity of synthetic crystalline materials, but developing strategies that target "self-limiting" assemblies has remained a challenge. Among these, self-closing structures, in which the local curvature defines the finite global size, are prone to polymorphism due to thermal bending fluctuations, a problem that worsens with increasing target size. Here, we show that assembly complexity can be used to eliminate this source of polymorphism in the assembly of tubules. Using many distinct components, we prune the local density of off-target geometries, increasing the selectivity of the tubule width and helicity to nearly 100%. We further show that by reducing the design constraints to target either the pitch or the width alone, fewer components are needed to reach complete selectivity. Combining experiments with theory, we reveal an economical limit, which determines the minimum number of components required to create arbitrary assembly sizes with full selectivity.

6.
Cancer Lett ; : 217100, 2024 Jul 03.
Artículo en Inglés | MEDLINE | ID: mdl-38969158

RESUMEN

Immune checkpoint inhibitors (ICIs) cause immune-related adverse events (irAEs) across various organ systems including oral health complications such as dry mouth and stomatitis. In this study, we aimed to determine the risk of periodontitis among patients on immune checkpoint inhibitors (ICIs) and to test the associations between ICI-associated periodontitis and other immune-related adverse events (irAEs). We performed a retrospective cohort study involving adult cancer patients between January 2010 and November 2021. Patients on an ICI were propensity score-matched to patients not on an ICI. The primary outcome was the occurrence of periodontitis. ICIs included programmed cell death 1 (PD-1) inhibitors programmed cell death ligand 1 (PD-L1) inhibitors, and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors. The risk of periodontitis following ICI use was derived through a Cox proportional hazard model and Kaplan-Meier survival analysis. Overall, 868 patients on an ICI were matched to patients not on an ICI. Among the ICI cohort, 41 (4.7%) patients developed periodontitis. The incidence rate of periodontitis was significantly higher in patients on an ICI than in patients not on an ICI (55.3 vs 25.8 per 100 patient-years, incidence rate ratio=2.14, 95% CI=1.38-3.33). Both the use of PD-L1 inhibitors (multivariate HR=2.5, 95%CI=1.3-4.7) and PD-1 inhibitors (multivariate HR=2.0, 95%CI=1.2-3.2) were associated with the risk of periodontitis. The presence of immune-related periodontitis was associated with better overall survival (not reached vs 17 months, log-rank p-value<0.001), progression-free survival (14.9 vs 5.6 months, log-rank p-value=0.01), and other concomitant immune-related cutaneous adverse events. In conclusion, ICI was associated with an increased risk of periodontitis. Immune-related periodontitis as an irAE was associated with better cancer survival and concomitant cutaneous irAEs.

7.
Proc Natl Acad Sci U S A ; 121(28): e2403130121, 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38950369

RESUMEN

DNA polymerase κ (Polκ) is a specialized polymerase that has multiple cellular roles such as translesion DNA synthesis, replication of repetitive sequences, and nucleotide excision repair. We have developed a method for capturing DNA synthesized by Polκ utilizing a Polκ-specific substrate, N2-(4-ethynylbenzyl)-2'-deoxyguanosine (EBndG). After shearing of the DNA into 200 to 500 bp lengths, the EBndG-containing DNA was covalently bound to biotin using the Cu(I)-catalyzed alkyne-azide cycloaddition reaction and isolated with streptavidin beads. Isolated DNA was then ligated to adaptors, followed by PCR amplification and next-generation sequencing to generate genome-wide repair maps. We have termed this method polymerase κ sequencing. Here, we present the human genome maps for Polκ activity in an undamaged cell line. We found that Polκ activity was enhanced in GC-rich regions, euchromatin regions, the promoter of genes, and in DNA that is replicated early in the S phase.


Asunto(s)
ADN Polimerasa Dirigida por ADN , Fibroblastos , Genoma Humano , Humanos , ADN Polimerasa Dirigida por ADN/metabolismo , Fibroblastos/metabolismo , Reparación del ADN , ADN/metabolismo , ADN/genética , Línea Celular , Replicación del ADN
8.
J Am Chem Soc ; 2024 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-38951503

RESUMEN

Kinetic proofreading is used throughout natural systems to enhance the specificity of molecular recognition. At its most basic level, kinetic proofreading uses a supply of chemical fuel to drive a recognition interaction out of equilibrium, allowing a single free-energy difference between correct and incorrect targets to be exploited two or more times. Despite its importance in biology, there has been little effort to incorporate kinetic proofreading into synthetic systems in which molecular recognition is important, such as nucleic acid nanotechnology. In this article, we introduce a DNA strand displacement-based kinetic proofreading motif, showing that the consumption of a DNA-based fuel can be used to enhance molecular recognition during a templated dimerization reaction. We then show that kinetic proofreading can enhance the specificity with which a probe discriminates single nucleotide mutations, both in terms of the initial rate with which the probe reacts and the long-time behavior.

9.
Artículo en Inglés | MEDLINE | ID: mdl-38961821

RESUMEN

Alzheimer's Disease (AD) is the 5th leading cause of death in older adults and treatment options are severely lacking. Recent findings demonstrate a strong relationship between skeletal muscle and cognitive function, with evidence supporting that muscle quality and cognitive function are positively correlated in older adults. Conversely, decreased muscle function is associated with a 3-fold increased risk of cognitive decline. Based on these observations, the purpose of this study was to investigate the negative effects of muscle disuse (via a model of hindlimb immobilization (HLI)) on hippocampal insulin sensitivity and mitochondrial function and identify the potential mechanisms involved. HLI for 10 days in 4-month-old female Wistar rats resulted in the following novel findings: 1) hippocampal insulin resistance and deficits in whole body glucose homeostasis, 2) dramatically increased mitochondrial reactive oxygen species (ROS) production in the hippocampus, 3) elevated markers for amyloidogenic cleavage of APP and tau protein in the hippocampus, 4) and reduced BDNF expression. These findings were associated with global changes in iron homeostasis, with muscle disuse producing muscle iron accumulation in association with decreased serum and whole brain iron levels. We report the novel finding that muscle disuse alters brain iron homeostasis and reveal a strong negative correlation between muscle and brain iron content. Overall, HLI-induced muscle disuse has robust negative effects on hippocampal insulin sensitivity and ROS production in association with altered brain iron homeostasis. This work provides potential novel mechanisms that may help explain how loss of muscle function contributes to cognitive decline and AD risk.

10.
Parasit Vectors ; 17(1): 290, 2024 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-38971776

RESUMEN

BACKGROUND: Aedes and Anopheles mosquitoes are responsible for tremendous global health burdens from their transmission of pathogens causing malaria, lymphatic filariasis, dengue, and yellow fever. Innovative vector control strategies will help to reduce the prevalence of these diseases. Mass rearing of mosquitoes for research and support of these strategies presently depends on meals of vertebrate blood, which is subject to acquisition, handling, and storage issues. Various blood-free replacements have been formulated for these mosquitoes, but none of these replacements are in wide use, and little is known about their potential impact on competence of the mosquitoes for Plasmodium infection. METHODS: Colonies of Aedes aegypti and Anopheles stephensi were continuously maintained on a blood-free replacement (SkitoSnack; SS) or bovine blood (BB) and monitored for engorgement and hatch rates. Infections of Ae. aegypti and An. stephensi were assessed with Plasmodium gallinaceum and P. falciparum, respectively. RESULTS: Replicate colonies of mosquitoes were maintained on BB or SS for 10 generations of Ae. aegypti and more than 63 generations of An. stephensi. The odds of engorgement by SS- relative to BB-maintained mosquitoes were higher for both Ae. aegypti (OR = 2.6, 95% CI 1.3-5.2) and An. stephensi (OR 2.7, 95% CI 1.4-5.5), while lower odds of hatching were found for eggs from the SS-maintained mosquitoes of both species (Ae. aegypti OR = 0.40, 95% CI 0.26-0.62; An. stephensi OR = 0.59, 95% CI 0.36-0.96). Oocyst counts were similar for P. gallinaceum infections of Ae. aegypti mosquitoes maintained on SS or BB (mean ratio = [mean on SS]/[mean on BB] = 1.11, 95% CI 0.85-1.49). Similar oocyst counts were also observed from the P. falciparum infections of SS- or BB-maintained An. stephensi (mean ratio = 0.76, 95% CI 0.44-1.37). The average counts of sporozoites/mosquito showed no evidence of reductions in the SS-maintained relative to BB-maintained mosquitoes of both species. CONCLUSIONS: Aedes aegypti and An. stephensi can be reliably maintained on SS over multiple generations and are as competent for Plasmodium infection as mosquitoes maintained on BB. Use of SS alleviates the need to acquire and preserve blood for mosquito husbandry and may support new initiatives in fundamental and applied research, including novel manipulations of midgut microbiota and factors important to the mosquito life cycle and pathogen susceptibility.


Asunto(s)
Aedes , Anopheles , Mosquitos Vectores , Animales , Aedes/parasitología , Aedes/fisiología , Anopheles/parasitología , Anopheles/fisiología , Mosquitos Vectores/parasitología , Mosquitos Vectores/fisiología , Plasmodium gallinaceum/fisiología , Plasmodium falciparum/fisiología , Bovinos , Femenino , Sangre/parasitología , Conducta Alimentaria
11.
Synth Biol (Oxf) ; 9(1): ysae010, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38973982

RESUMEN

Data science is playing an increasingly important role in the design and analysis of engineered biology. This has been fueled by the development of high-throughput methods like massively parallel reporter assays, data-rich microscopy techniques, computational protein structure prediction and design, and the development of whole-cell models able to generate huge volumes of data. Although the ability to apply data-centric analyses in these contexts is appealing and increasingly simple to do, it comes with potential risks. For example, how might biases in the underlying data affect the validity of a result and what might the environmental impact of large-scale data analyses be? Here, we present a community-developed framework for assessing data hazards to help address these concerns and demonstrate its application to two synthetic biology case studies. We show the diversity of considerations that arise in common types of bioengineering projects and provide some guidelines and mitigating steps. Understanding potential issues and dangers when working with data and proactively addressing them will be essential for ensuring the appropriate use of emerging data-intensive AI methods and help increase the trustworthiness of their applications in synthetic biology.

12.
Front Mol Neurosci ; 17: 1392715, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38979476

RESUMEN

Zinc is a ubiquitous contaminant in many buffers, purified products and common labware that has previously been suggested to impact on the results of functional GlyR studies and may inadvertently cause the effectiveness of some GlyR modulators to be over-estimated. This could greatly impact the assessment of potential drug-candidates and contribute to the reduced effectiveness of compounds that reach clinical stages. This is especially true for GlyR modulators being developed for pain therapeutics due to the changes in spinal zinc concentrations that have been observed during chronic pain conditions. In this study we use two-electrode voltage clamp electrophysiology to evaluate the metal chelators tricine and Ca-EDTA, and show that tricine produces inhibitory effects at GlyRα1 that are not mediated by zinc. We also utilized the zinc insensitive W170S mutation as a tool to validate metal chelators and confirm that zinc contamination has not impacted the examination of lipid modulators previously developed by our lab. This study helps to further develop methods to negate the impact of contaminating zinc in functional studies of GlyRs which should be incorporated into future studies that seek to characterize the activity of novel modulators at GlyRs.

13.
ACS Nano ; 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38981100

RESUMEN

Recent advances enable the creation of nanoscale building blocks with complex geometries and interaction specificities for self-assembly. This nearly boundless design space necessitates design principles for defining the mutual interactions between multiple particle species to target a user-specified complex structure or pattern. In this article, we develop a symmetry-based method to generate the interaction matrices that specify the assembly of two-dimensional tilings, which we illustrate using equilateral triangles. By exploiting the allowed 2D symmetries, we develop an algorithmic approach by which any periodic 2D tiling can be generated from an arbitrarily large number of subunit species, notably addressing an unmet challenge of engineering 2D crystals with periodicities that can be arbitrarily larger than the subunit size. To demonstrate the utility of our design approach, we encode specific interactions between triangular subunits synthesized by DNA origami and show that we can guide their self-assembly into tilings with a wide variety of symmetries, using up to 12 unique species of triangles. By conjugating specific triangles with gold nanoparticles, we fabricate gold-nanoparticle supracrystals whose lattice parameter spans up to 300 nm. Finally, to generate economical design rules, we compare the design economy of various tilings. In particular, we show that (1) higher symmetries allow assembly of larger unit cells with fewer subunits and (2) linear supracrystals can be designed more economically using linear primitive unit cells. This work provides a simple algorithmic approach to designing periodic assemblies, aiding in the multiscale assembly of supracrystals of nanostructured "meta-atoms" with engineered plasmonic functions.

14.
Br J Pharmacol ; 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38982742

RESUMEN

BACKGROUND AND PURPOSE: Sodium glucose cotransporter 2 inhibitors (SGLT2i) have emerged as a potent therapy for heart failure with preserved ejection fraction (HFpEF). Hydrogen sulphide (H2S), a well-studied cardioprotective agent, could be beneficial in HFpEF. SGLT2i monotherapy and combination therapy involving an SGLT2i and H2S donor in two preclinical models of cardiometabolic HFpEF was investigated. EXPERIMENTAL APPROACH: Nine-week-old C57BL/6N mice received L-NAME and a 60% high fat diet for five weeks. Mice were then randomized to either control, SGLT2i monotherapy or SGLT2i and H2S donor, SG1002, for five additional weeks. Ten-week-old ZSF1 obese rats were randomized to control, SGLT2i or SGLT2i and SG1002 for 8 weeks. SG1002 monotherapy was investigated in additional animals. Cardiac function (echocardiography and haemodynamics), exercise capacity, glucose handling and multiorgan pathology were monitored during experimental protocols. KEY RESULTS: SGLT2i treatment improved E/e' ratio and treadmill exercise in both models. Combination therapy afforded increases in cardiovascular sulphur bioavailability that coincided with improved left end-diastolic function (E/e' ratio), exercise capacity, metabolic state, cardiorenal fibrosis, and hepatic steatosis. Follow-up studies with SG1002 monotherapy revealed improvements in diastolic function, exercise capacity and multiorgan histopathology. CONCLUSIONS AND IMPLICATIONS: SGLT2i monotherapy remediated pathological complications exhibited by two well-established HFpEF models. Adjunctive H2S therapy resulted in further improvements of cardiometabolic perturbations beyond SGLT2i monotherapy. Follow-up SG1002 monotherapy studies inferred an improved phenotype with combination therapy beyond either monotherapy. These data demonstrate the differing effects of SGLT2i and H2S therapy while also revealing the superior efficacy of the combination therapy in cardiometabolic HFpEF.

15.
J Chem Phys ; 161(2)2024 Jul 14.
Artículo en Inglés | MEDLINE | ID: mdl-38984957

RESUMEN

The plane-wave pseudopotential (PW-PP) formalism is widely used for the first-principles electronic structure calculation of extended periodic systems. The PW-PP approach has also been adapted for real-time time-dependent density functional theory (RT-TDDFT) to investigate time-dependent electronic dynamical phenomena. In this work, we detail recent advances in the PW-PP formalism for RT-TDDFT, particularly how maximally localized Wannier functions (MLWFs) are used to accelerate simulations using the exact exchange. We also discuss several related developments, including an anti-Hermitian correction for the time-dependent MLWFs (TD-MLWFs) when a time-dependent electric field is applied, the refinement procedure for TD-MLWFs, comparison of the velocity and length gauge approaches for applying an electric field, and elimination of long-range electrostatic interaction, as well as usage of a complex absorbing potential for modeling isolated systems when using the PW-PP formalism.

16.
J Am Chem Soc ; 2024 Jul 09.
Artículo en Inglés | MEDLINE | ID: mdl-38980188

RESUMEN

Carbon electrodes typically display sluggish electron transfer kinetics due to the adsorption of adventitious molecules that effectively insulate the surface. Here, we describe a method for rendering graphitic carbon electrodes permanently hydrophilic by functionalization with 4-(diazonium)benzenesulfonic acid. In aqueous electrolytes, these hydrophilic carbon electrodes exhibit metal-like specific capacitance (∼40 µF/cm2) as measured by cyclic voltammetry, suggesting a change in the double-layer structure at the carbon surface. Additionally, the modified electrodes show fast charge transfer kinetics to outer-sphere one-electron redox couples such as ferro-/ferricyanide as well as improved electron transfer kinetics in alkaline aqueous redox flow batteries.

18.
Artículo en Inglés | MEDLINE | ID: mdl-38995211

RESUMEN

BACKGROUND: Nighttime BP and BP dipping (daytime-nighttime BP) are prognostic for cardiovascular disease. Compared with other racial/ethnic groups, Black Americans exhibit elevated nighttime BP and attenuated BP dipping. Neighborhood deprivation may contribute to disparities in cardiovascular health, but its effects on resting and ambulatory BP patterns in young adults is unclear. Therefore, we examined associations between neighborhood deprivation with resting and nighttime BP and BP dipping in young Black and White adults. METHODS: We recruited 19 Black and 28 White participants (23 M/24 F, 21±1 years, body mass index: 26±4 kg/m2) for 24-hour ambulatory BP monitoring. We assessed resting BP, nighttime BP, and BP dipping (absolute dip and nighttime:daytime BP ratio). We used the area deprivation index (ADI) to assess average neighborhood deprivation during early- and mid-childhood, and adolescence. RESULTS: Compared with White participants, Black participants exhibited higher resting systolic and diastolic BP (ps≤0.029), nighttime systolic BP (114±9 vs. 108±9 mmHg, p=0.049), diastolic BP (63±8 vs. 57±7 mmHg, p=0.010), and attenuated absolute systolic BP dipping (12±5 vs. 9±7 mmHg, p=0.050). Black participants experienced greater average ADI scores compared with White participants (110(10) vs. 97(22), p=0.002), and select ADI scores correlated with resting BP and some ambulatory BP measures. Within each race, select ADI scores correlated with some BP measures for Black participants, but there were no ADI and BP correlations for White participants. CONCLUSIONS: Our findings suggest neighborhood deprivation may contribute to higher resting BP and impaired ambulatory BP patterns in young adults warranting further investigation in larger cohorts.

19.
Nat Commun ; 15(1): 5804, 2024 Jul 10.
Artículo en Inglés | MEDLINE | ID: mdl-38987268

RESUMEN

Environmental and physiological situations can challenge the balance between protein synthesis and folding capacity of the endoplasmic reticulum (ER) and cause ER stress, a potentially lethal condition. The unfolded protein response (UPR) restores ER homeostasis or actuates programmed cell death (PCD) when ER stress is unresolved. The cell fate determination mechanisms of the UPR are not well understood, especially in plants. Here, we integrate genetics and ER stress profiling with natural variation and quantitative trait locus analysis of 350 natural accessions of the model species Arabidopsis thaliana. Our analyses implicate a single nucleotide polymorphism to the loss of function of the general PCD regulator BON-ASSOCIATED PROTEIN2 (BAP2) in UPR outcomes. We establish that ER stress-induced BAP2 expression is antagonistically regulated by the UPR master regulator, inositol-requiring enzyme 1 (IRE1), and that BAP2 controls adaptive UPR amplitude in ER stress and ignites pro-death mechanisms in conditions of UPR insufficiency.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Estrés del Retículo Endoplásmico , Regulación de la Expresión Génica de las Plantas , Respuesta de Proteína Desplegada , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Respuesta de Proteína Desplegada/genética , Estrés del Retículo Endoplásmico/genética , Retículo Endoplásmico/metabolismo , Apoptosis/genética , Proteínas Serina-Treonina Quinasas/metabolismo , Proteínas Serina-Treonina Quinasas/genética , Sitios de Carácter Cuantitativo , Polimorfismo de Nucleótido Simple
20.
J Phys Chem B ; 128(27): 6476-6491, 2024 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-38951498

RESUMEN

The chimeric oncoprotein Bcr-Abl is the causative agent of virtually all chronic myeloid leukemias and a subset of acute lymphoblastic leukemias. As a result of the so-called Philadelphia chromosome translocation t(9;22), Bcr-Abl manifests as a constitutively active tyrosine kinase, which promotes leukemogenesis by activation of cell cycle signaling pathways. Constitutive and oncogenic activation is mediated by an N-terminal coiled-coil oligomerization domain in Bcr (Bcr-CC), presenting a therapeutic target for inhibition of Bcr-Abl activity toward the treatment of Bcr-Abl+ leukemias. Previously, we demonstrated that a rationally designed Bcr-CC mutant, CCmut3, exerts a dominant negative effect upon Bcr-Abl activity by preferential oligomerization with Bcr-CC. Moreover, we have shown that conjugation to a leukemia-specific cell-penetrating peptide (CPP-CCmut3) improves intracellular delivery and activity. However, our full-length CPP-CCmut3 construct (81 aa) is encumbered by an intrinsically high degree of conformational variability and susceptibility to proteolytic degradation relative to traditional small-molecule therapeutics. Here, we iterate a new generation of CCmut3 inhibitors against Bcr-CC-mediated Bcr-Abl assembly designed to address these constraints through incorporation of all-hydrocarbon staples spanning i and i + 7 positions in α-helix 2 (CPP-CCmut3-st). We utilize computational modeling and biomolecular simulation to evaluate single- and double-stapled CCmut3 candidates in silico for dynamics and binding energetics. We further model a truncated system characterized by the deletion of α-helix 1 and the flexible loop linker, which are known to impart high conformational variability. To study the impact of the N-terminal cyclic CPP toward model stability and inhibitor activity, we also model the full-length and truncated systems devoid of the CPP, with a cyclized CPP, and with an open-configuration CPP, for a total of six systems that comprise our library. From this library, we present lead-stapled peptide candidates to be synthesized and evaluated experimentally as our next iteration of inhibitors against Bcr-Abl.


Asunto(s)
Proteínas de Fusión bcr-abl , Leucemia Mielógena Crónica BCR-ABL Positiva , Proteínas de Fusión bcr-abl/antagonistas & inhibidores , Proteínas de Fusión bcr-abl/metabolismo , Proteínas de Fusión bcr-abl/química , Leucemia Mielógena Crónica BCR-ABL Positiva/tratamiento farmacológico , Leucemia Mielógena Crónica BCR-ABL Positiva/metabolismo , Humanos , Inhibidores de Proteínas Quinasas/química , Inhibidores de Proteínas Quinasas/farmacología , Inhibidores de Proteínas Quinasas/metabolismo , Modelos Moleculares , Simulación de Dinámica Molecular , Antineoplásicos/química , Antineoplásicos/farmacología , Péptidos de Penetración Celular/química , Péptidos de Penetración Celular/farmacología , Péptidos de Penetración Celular/metabolismo
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