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1.
Melanoma Res ; 34(4): 285-295, 2024 Aug 01.
Article in English | MEDLINE | ID: mdl-38847739

ABSTRACT

Uveal melanoma is the most common intraocular tumor in adults. Our group has previously developed a human uveal melanoma animal model; however, adverse effects caused by the immunosuppressive agent, cyclosporine A, prevented animals from surviving more than 12 weeks. In this study, we tested multiple cyclosporine A doses over an extended disease course up to 20 weeks, providing complete clinical imaging of intraocular tumors, histopathological analysis and liquid biopsy biomarker analysis. Twenty albino rabbits were divided into four groups with different daily cyclosporine A schedules (0-10 mg/kg) and inoculated with human uveal melanoma cell lines, 92.1 or MP41, into the suprachoroidal space. Rabbits were monitored with fundoscopy, ultrasound and optical coherence tomography. Intraocular tumors (macroscopic or microscopic) were detected in all study animals. Tumor size and growth were correlated to cyclosporine A dose, with tumors regressing when cyclosporine A was arrested. All tumors expressed HMB-45 and MelanA; however, tumor size, pigmentation and cell morphology differed in 92.1 vs. MP41 tumors. Finally, across all groups, circulating tumor DNA from plasma and aqueous humor was detected earlier than tumor detection by imaging and correlated to tumor growth. In conclusion, using three clinically relevant imaging modalities (fundoscopy, ultrasonography and optical coherence tomography) and liquid biopsy, we were successfully able to monitor tumor progression in our rabbit xenograft model of human uveal melanoma.


Subject(s)
Melanoma , Uveal Neoplasms , Animals , Uveal Neoplasms/pathology , Rabbits , Melanoma/pathology , Humans , Liquid Biopsy/methods , Disease Models, Animal , Xenograft Model Antitumor Assays , Cell Line, Tumor
2.
Front Mol Biosci ; 11: 1382070, 2024.
Article in English | MEDLINE | ID: mdl-38721276

ABSTRACT

Currently, esophageal adenocarcinoma (EAC) research is hindered by a dearth of adequate models to study this disease. Traditional cell line and genetically engineered mouse models are lacking in biological and physiological significance, whilst the inefficiency of patient-derived xenografts limit their potential applications. This review describes the landscape of EAC research using patient-derived organoids (PDOs). Here, we detail the methods of establishment and optimization of EAC PDO cultures, as well as current and prospective applications of these models. We further highlight a crucial knowledge gap in the mechanisms of EAC transformation from its precursor lesion, Barrett's esophagus (BE). As such, we also describe the culture requirements of BE PDOs and attempts to model tumorigenesis using PDO models.

3.
J Am Chem Soc ; 146(19): 13666-13675, 2024 May 15.
Article in English | MEDLINE | ID: mdl-38709144

ABSTRACT

High-spin organic tetraradicals with significant intramolecular exchange interactions have high potential for advanced technological applications and fundamental research, but examples reported to date exhibit limited stability and processability. In this work, we designed the first tetraradical based on an oxoverdazyl core and nitronyl nitroxide radicals and successfully synthesized it using a palladium-catalyzed cross-coupling reaction of an oxoverdazyl radical bearing three iodo-phenylene moieties with a gold(I) nitronyl nitroxide-2-ide complex in the presence of a recently developed efficient catalytic system. The molecular and crystal structures of the tetraradical were confirmed by single crystal X-ray diffraction analysis. The tetraradical possesses good thermal stability with decomposition onset at ∼125 °C in an inert atmosphere; in a toluene solution upon prolonged heating at 90 °C in air, no decomposition was observed. The resulting unique verdazyl-nitroxide conjugate was thoroughly studied using a range of experimental and theoretical techniques, such as SQUID magnetometry of polycrystalline powders, EPR spectroscopy in various matrices, cyclic voltammetry, and high-level quantum chemical calculations. All collected data confirm the high thermal stability of the resulting tetraradical and quintet multiplicity of its ground state, which makes the synthesis of this important paramagnet a new milestone in the field of creating high-spin systems.

4.
Cell Metab ; 2024 May 03.
Article in English | MEDLINE | ID: mdl-38718792

ABSTRACT

Diabetic retinopathy is a microvascular disease that causes blindness. Using acid sphingomyelinase knockout mice, we reported that ceramide generation is critical for diabetic retinopathy development. Here, in patients with proliferative diabetic retinopathy, we identify vitreous ceramide imbalance with pathologic long-chain C16-ceramides increasing and protective very long-chain C26-ceramides decreasing. C16-ceramides generate pro-inflammatory/pro-apoptotic ceramide-rich platforms on endothelial surfaces. To geo-localize ceramide-rich platforms, we invented a three-dimensional confocal assay and showed that retinopathy-producing cytokines TNFα and IL-1ß induce ceramide-rich platform formation on retinal endothelial cells within seconds, with volumes increasing 2-logs, yielding apoptotic death. Anti-ceramide antibodies abolish these events. Furthermore, intravitreal and systemic anti-ceramide antibodies protect from diabetic retinopathy in standardized rodent ischemia reperfusion and streptozotocin models. These data support (1) retinal endothelial ceramide as a diabetic retinopathy treatment target, (2) early-stage therapy of non-proliferative diabetic retinopathy to prevent progression, and (3) systemic diabetic retinopathy treatment; and they characterize diabetic retinopathy as a "ceramidopathy" reversible by anti-ceramide immunotherapy.

5.
Cancer Cell Int ; 24(1): 180, 2024 May 23.
Article in English | MEDLINE | ID: mdl-38783299

ABSTRACT

BACKGROUND: Although rare, uveal melanoma (UM) is a life-threatening malignancy. Understanding its biology is necessary to improve disease outcome. Three-dimensional (3D) in vitro culture methods have emerged as tools that incorporate physical and spatial cues that better mimic tumor biology and in turn deliver more predictive preclinical data. Herein, we comprehensively characterize UM cells under different 3D culture settings as a suitable model to study tumor cell behavior and therapeutic intervention. METHODS: Six UM cell lines were tested in two-dimensional (2D) and 3D-culture conditions. For 3D cultures, we used anchorage-dependent (AD) methods where cells were embedded or seeded on top of basement membrane extracts and anchorage-free (AF) methods where cells were seeded on agarose pre-coated plates, ultra-low attachment plates, and on hanging drops, with or without methylcellulose. Cultures were analyzed for multicellular tumor structures (MCTs) development by phase contrast and confocal imaging, and cell wellbeing was assessed based on viability, membrane integrity, vitality, apoptotic features, and DNA synthesis. Vascular endothelial growth factor (VEGF) production was evaluated under hypoxic conditions for cell function analysis. RESULTS: UM cells cultured following anchorage-free methods developed MCTs shaped as spheres. Regardless of their sizes and degree of compaction, these spheres displayed an outer ring of viable and proliferating cells, and a core with less proliferating and apoptotic cells. In contrast, UM cells maintained under anchorage-dependent conditions established several morphological adaptations. Some remained isolated and rounded, formed multi-size irregular aggregates, or adopted a 2D-like flat appearance. These cells invariably conserved their metabolic activity and conserved melanocytic markers (i.e., expression of Melan A/Mart-1 and HMB45). Notably, under hypoxia, cells maintained under 3D conditions secrete more VEGF compared to cells cultured under 2D conditions. CONCLUSIONS: Under an anchorage-free environment, UM cells form sphere-like MCTs that acquire attributes reminiscent of abnormal vascularized solid tumors. UM cells behavior in anchorage-dependent manner exposed diverse cells populations in response to cues from an enriched extracellular matrix proteins (ECM) environment, highlighting the plasticity of UM cells. This study provides a 3D cell culture platform that is more predictive of the biology of UM. The integration of such platforms to explore mechanisms of ECM-mediated tumor resistance, metastatic abilities, and to test novel therapeutics (i.e., anti-angiogenics and immunomodulators) would benefit UM care.

6.
J Clin Med ; 13(10)2024 May 15.
Article in English | MEDLINE | ID: mdl-38792454

ABSTRACT

Background: The aim of this study was to evaluate the short-term efficacy and safety of the Paul Glaucoma Implant (PGI) in pediatric eyes diagnosed with glaucoma following congenital cataract surgery (GFCS). Methods: A retrospective, single-center, descriptive study was conducted on consecutive children diagnosed with GFCS who underwent PGI implantation between July 2022 and November 2023 at the University Medical Center Mainz. The primary outcome measure was the reduction in IOP at the last follow-up visit. Results: Ten eyes of nine children were included in the study. The mean follow-up time was 7.70 ± 4.22 months (4.68-10.72 months). At the end of the study follow-up, the mean (95% CI) reduction in IOP was -14.8 ± 8.73 mmHg (-8.56 to -21.04 mmHg, p < 0.001). At the last follow-up, 30.0% (3/10) of patients achieved an IOP (intraocular pressure) of ≥6 and ≤21 mmHg with a reduction in IOP of ≥25% without treatment, while 90.0% (9/10) achieved this target IOP regardless of glaucoma medication treatment. The mean number of antiglaucoma medications was significantly reduced from 3.50 (IQR = 1) to 2.0 (IQR = 2, p = 0.01), and the visual acuity logMAR improved from 1.26 ± 0.62 to 1.03 ± 0.48 (p = 0.04). Only one eye experienced numerical hypotony (4 mmHg) without choroidal detachment or anterior chamber shallowing within the first 24 h. No other adverse events were observed during the follow-up period. Conclusions: PGI implantation significantly lowered IOP and the number of antiglaucoma eye drops with a favorable safety profile in children diagnosed with GFCS, thereby achieving a high rate of qualified surgical success in the short term.

7.
J Glaucoma ; 2024 May 06.
Article in English | MEDLINE | ID: mdl-38709193

ABSTRACT

PURPOSE: This study assesses morphological characteristics using SD-OCT in patients with hypotony maculopathy (HM) following glaucoma filtering surgery and evaluates the results of its treatment. MATERIAL AND METHODS: Retrospective analysis of all HM patients between January 2019 and March 2023. Inclusion criteria consisted of both pre-operative and post-revision SD-OCT images of the macula and the presence of HM as observed on OCT images preoperatively. HM was graded according to its appearance in OCT both pre- and post-revision surgery. Change in visual acuity and IOP were assessed. RESULTS: 45 eyes of 45 patients were included. 21 eyes had HM limited to retinal pigment epithelium (RPE), 18 eyes had involvement of RPE and photoreceptor layers and 6 eyes had additional intra- or subretinal edema. After revision surgery with IOP elevation, 64% of eyes had complete HM regression with no HM signs in OCT imaging. 80% of patients achieved at least one grade improvement in HM. Preoperative visual acuity increased from 0.7±0.4 (logMAR) to 0.4±0.4 at 2 weeks postoperatively, over the course of an increase of IOP from 3.5±1.8 mmHg to 17.1±10.6 mmHg at day one. Eyes with complete HM regression had higher IOP at day 1 compared to those without improvement (P=0.04). The median time between HM onset and revision was 10.0 days for those with complete regression and 27 days for those without improvement (P=0.04). CONCLUSIONS: Bleb revision procedures for HM following glaucoma filtering surgery show promising outcomes, including notable improvements in visual acuity and IOP. The timing of revision surgery appears to influence outcome. In our study earlier intervention was associated with better results. Even delayed surgeries can lead to an improvement, although complete morphological restoration may not be achieved in advanced grades of HM.

8.
Article in English | MEDLINE | ID: mdl-38629178

ABSTRACT

AIM: To understand the current usage of eviQ Cancer Treatments Online (www.eviQ.org.au), an Australian, open-access website providing evidence-based and consensus-driven cancer treatment protocols and information, and the extent to which it is meeting its intended outcomes and providing value to its users. METHODS: A mixed-method evaluation was conducted in 2020-2022 which included a review of key program documentation and website usage data, and delivery of a focused online survey to its users. RESULTS: In 2022, 329 clinicians representing all Australian states and territories contributed to eviQ content development and review. eviQ content continues to grow with a 15.2% increase in total content from 2019 to 2022.  eviQ website users continue to grow with 90,000 total monthly users in 2022, representing a 166% increase from 2018. The proportion of international users compared to Australian users continues to grow with 57% of total users in Australia and 43% international in 2022. Of 466 survey responses, the most cited reason for eviQ use was for information on side effects/toxicity (67%). Ninety-three percent (93%) of respondents either agreed or strongly agreed that eviQ contributed to both health professionals providing the best evidence-based treatment and care and improving the standardization of treatment and care provided. CONCLUSION:  eviQ is embedded in Australian clinical practice, highly valued, and relied upon by users. Users agree that eviQ has a positive impact on patients by supporting the delivery of evidence-based treatment and that eviQ contributed to patients' improved health outcomes and quality of life. eviQ's increasing international usage should be explored.

9.
Phys Chem Chem Phys ; 26(15): 11893-11909, 2024 Apr 17.
Article in English | MEDLINE | ID: mdl-38568204

ABSTRACT

Electroactive polymer materials are known to play important roles in a vast spectrum of modern applications such as in supercapacitors, fuel cells, batteries, medicine, and smart materials, etc. They are usually divided into two main groups: first, conducting π-conjugated organic polymers, which conduct electricity by cation-radicals delocalized over a polymer chain; second, redox polymers, which conduct electricity via an electron-hopping mechanism. Polymer materials belonging to these two main groups have been thoroughly studied and their thermodynamic and kinetic models have been built. However, in recent decades a lot of mixed-type materials have been discovered and investigated. To the best of our knowledge, a thermodynamic-based description of conducting redox polymers (CRPs) has not been provided yet. In this work, we present a thermodynamic model for voltammetric responses of conducting redox polymers. The derived model allows one to extract thermodynamic parameters of a CRP including the polaron delocalization degree and redox active groups interaction constant. The model was verified with voltammetric experiments on three recently synthesized CRPs and showed a satisfactory predictive ability. The simulated data are in good agreement with the experiment. We believe that developing theoretical descriptions for CRPs and other types of electroactive materials with the ability to simulate their electrochemical responses may help in future realization of new systems with superior characteristics for electrochemical energy storage, chemical sensors, pharmacological applications, etc.

10.
Macromol Rapid Commun ; : e2400074, 2024 Apr 09.
Article in English | MEDLINE | ID: mdl-38593474

ABSTRACT

Redox-conducting polymers based on SalEn-type complexes have attracted considerable attention due to their potential applications in electrochemical devices. However, their charge transfer mechanisms, physical and electrochemical properties remain unclear, hindering their rational design and optimization. This study aims to establish the influence of monomer geometry on the polymer's properties by investigating the properties of novel nonplanar SalEn-type complexes, poly[N,N'-bis(salicylidene)propylene-2-(hydroxy)diaminonickel(II)], and its analog with 2,2,6,6-tetramethylpiperidinyl-N-oxyl (TEMPO)-substituted bridge (MTS). To elucidate the charge transfer mechanism, operando UV-Vis spectroelectrochemical analysis, electrochemical impedance spectroscopy, and electron paramagnetic resonance are employed. Introducing TEMPO into the bridge moiety enhanced the specific capacity of the poly(MTS) material to 95 mA h g-1, attributed to TEMPO's and conductive backbone's charge storage capabilities. Replacement of the ethylenediimino-bridge with a 1,3-propylenediimino- bridge induced significant changes in the complex geometry and material's morphology, electrochemical, and spectral properties. At nearly the same potential, polaron and bipolaron particles emerged, suggesting intriguing features at the overlap point of the electroactivity potentials ranges of polaron-bipolaron and TEMPO, such as a disruption in the connection between TEMPO and the conjugation chain or intramolecular charge transfer. These results offer valuable insights for optimizing strategies to create organic materials with tailored properties for use in catalysis and battery applications.

11.
Epigenomes ; 8(2)2024 Apr 03.
Article in English | MEDLINE | ID: mdl-38651368

ABSTRACT

BACKGROUND: One of the mechanisms regulating the biological activity of tumor necrosis factor (TNF) in cells is the co-expression of TNFR1/TNFR2 receptors. A model with a differential level of receptor expression is required to evaluate the contribution of these mechanisms. AIM: The development of a cellular model to compare the effects of TNF on cells depending on the presence of both receptors and TNFR2 alone. METHODS: TNFR1 absence modifications of ZR-75/1 and K-562 cell lines were obtained by TNFR1 knockout. The presence of deletions was confirmed by Sanger sequencing, and the absence of cell membrane receptor expression was confirmed by flow cytometry. The dose-dependent effect of TNF on intact and knockout cells was comparatively evaluated by the effect on the cell cycle, the type of cell death, and the profile of expressed genes. RESULTS: Knockout of TNFR1 resulted in a redistribution of TNFR2 receptors with an increased proportion of TNFR2+ cells in both lines and a multidirectional change in the density of expression in the lines (increased in K562 and decreased in ZR75/1). The presence of a large number of cells with high TNFR2 density in the absence of TNFR1 in the K562 cells was associated with greater sensitivity to TNF-stimulating doses and increased proliferation but did not result in a significant change in cell death parameters. A twofold increase in TNFR2+ cell distribution in this cell line at a reduced expression density in ZR75/1 cells was associated with a change in sensitivity to low cytokine concentrations in terms of proliferation; an overall increase in cell death, most pronounced at standard stimulating concentrations; and increased expression of the lymphocyte-activation gene groups, host-pathogen interaction, and innate immunity. CONCLUSIONS: The absence of TNFR1 leads to different variants of compensatory redistribution of TNFR2 in cellular models, which affects the type of cell response and the threshold level of sensitivity. The directionality of cytokine action modulation and sensitivity to TNF levels depends not only on the fraction of cells expressing TNFR2 but also on the density of expression.

12.
Angew Chem Int Ed Engl ; 63(27): e202317468, 2024 Jul 01.
Article in English | MEDLINE | ID: mdl-38572820

ABSTRACT

The formation of transient hybrid nanoscale metal species from homogeneous molecular precatalysts has been demonstrated by in situ NMR studies of catalytic reactions involving transition metals with N-heterocyclic carbene ligands (M/NHC). These hybrid structures provide benefits of both molecular complexes and nanoparticles, enhancing the activity, selectivity, flexibility, and regulation of active species. However, they are challenging to identify experimentally due to the unsuitability of standard methods used for homogeneous or heterogeneous catalysis. Utilizing a sophisticated solid-state NMR technique, we provide evidence for the formation of NHC-ligated catalytically active Pd nanoparticles (PdNPs) from Pd/NHC complexes during catalysis. The coordination of NHCs via C(NHC)-Pd bonding to the metal surface was first confirmed by observing the Knight shift in the 13C NMR spectrum of the frozen reaction mixture. Computational modeling revealed that as little as few NHC ligands are sufficient for complete ligation of the surface of the formed PdNPs. Catalytic experiments combined with in situ NMR studies confirmed the significant effect of surface covalently bound NHC ligands on the catalytic properties of the PdNPs formed by decomposition of the Pd/NHC complexes. This observation shows the crucial influence of NHC ligands on the activity and stability of nanoparticulate catalytic systems.

13.
Front Clin Diabetes Healthc ; 5: 1297422, 2024.
Article in English | MEDLINE | ID: mdl-38685920

ABSTRACT

Objective: Interventions for emerging adults (EAs) with type 1 diabetes (T1D) focus on goal setting, but little is known about how goal achievement relates to intervention outcomes. We examined how goals change, how goal achievement relates to diabetes outcomes, and identified barriers and facilitators to goal achievement. Method: EAs with T1D (N=29, M age=21.6 years, 57% female) were coached monthly to set a behavioral goal across a 3-month feasibility trial. Coaching notes were qualitatively coded regarding type, complexity, and changes in goals. Goal achievement was measured via daily responses to texts. HbA1c, self-efficacy, diabetes distress, and self-care were assessed pre- and post-intervention. Results: EAs frequently set food goals (79%) in combination with other goals. EAs overwhelmingly changed their goals (90%), with most increasing goal complexity. Goal achievement was high (79% of days) and not affected by goal change or goal complexity. Goal achievement was associated with increases in self-efficacy and self-care across time. Qualitative themes revealed that aspects of self-regulation and social-regulation were important for goal achievement. Conclusion: Meeting daily diabetes goals may enhance self-efficacy and self-care for diabetes. Practice Implications: Assisting EAs to reduce self-regulation challenges and enhance social support for goals may lead to better diabetes outcomes.

14.
Biochemistry (Mosc) ; 89(Suppl 1): S205-S223, 2024 Jan.
Article in English | MEDLINE | ID: mdl-38621751

ABSTRACT

The term "biomolecular condensates" is used to describe membraneless compartments in eukaryotic cells, accumulating proteins and nucleic acids. Biomolecular condensates are formed as a result of liquid-liquid phase separation (LLPS). Often, they demonstrate properties of liquid-like droplets or gel-like aggregates; however, some of them may appear to have a more complex structure and high-order organization. Membraneless microcompartments are involved in diverse processes both in cytoplasm and in nucleus, among them ribosome biogenesis, regulation of gene expression, cell signaling, and stress response. Condensates properties and structure could be highly dynamic and are affected by various internal and external factors, e.g., concentration and interactions of components, solution temperature, pH, osmolarity, etc. In this review, we discuss variety of biomolecular condensates and their functions in live cells, describe their structure variants, highlight domain and primary sequence organization of the constituent proteins and nucleic acids. Finally, we describe current advances in methods that characterize structure, properties, morphology, and dynamics of biomolecular condensates in vitro and in vivo.


Subject(s)
Biochemical Phenomena , Nucleic Acids , Biomolecular Condensates , Proteins , Cytoplasm
16.
J Gen Intern Med ; 2024 Mar 14.
Article in English | MEDLINE | ID: mdl-38485878

ABSTRACT

PURPOSE: Internal medicine residents care for clinically complex older adults and may experience increased moral distress due to knowledge gaps, time constraints, and institutional barriers. We conducted a phenomenological study to explore residents' experiences and challenges through the lens of uncertainty. METHODS: Between January and March 2022, six focus groups were conducted comprising a total of 13 internal medicine residents in postgraduate years 2 and 3, who had completed a required 2-week geriatrics rotation. Applying the Beresford taxonomy of uncertainty as a conceptual model, data were analyzed using the framework method. RESULTS: All challenging experiences described by residents caring for older adults were linked to uncertainty. Sources of uncertainty were categorized and mapped to the Beresford taxonomy: (1) lack of geriatrics knowledge or clinical guidelines (technical); (2) difficulty applying knowledge to complex older adults (conceptual); and (3) lack of longitudinal relationship with the older patient (personal). Residents identified capacity evaluation and discharge planning as two major geriatric knowledge areas linked with uncertainty. While the majority of residents reacted to uncertainty with some degree of distress, several reported positive coping strategies. CONCLUSIONS: Internal medicine residents face uncertainty when caring for older adults, particularly related to technical and conceptual factors. Strategies for mitigating uncertainty in the care of older adults are needed given links with moral distress and trainee well-being.

17.
Sci Adv ; 10(12): eadk6320, 2024 Mar 22.
Article in English | MEDLINE | ID: mdl-38507490

ABSTRACT

Several dolphin lineages have independently invaded freshwater systems. Among these, the evolution of the South Asian river dolphin Platanista and its relatives (Platanistidae) remains virtually unknown as fossils are scarce. Here, we describe Pebanista yacuruna gen. et sp. nov., a dolphin from the Miocene proto-Amazonia of Peru, recovered in phylogenies as the closest relative of Platanista. Morphological characters such as an elongated rostrum and large supraorbital crests, along with ecological interpretations, indicate that this odontocete was fully adapted to fresh waters. Pebanista constitutes the largest freshwater odontocete known, with an estimated body length of 3 meters, highlighting the ample resource availability and biotic diversity in the region, during the Early to Middle Miocene. The finding of Pebanista in proto-Amazonian layers attests that platanistids ventured into freshwater ecosystems not only in South Asia but also in South America, before the modern Amazon River dolphin, during a crucial moment for the Amazonian evolution.


Subject(s)
Biological Evolution , Dolphins , Animals , Ecosystem , Phylogeny , Fresh Water
18.
Cell Death Dis ; 15(3): 182, 2024 Mar 01.
Article in English | MEDLINE | ID: mdl-38429264

ABSTRACT

Caspase-2, one of the most evolutionarily conserved members of the caspase family, is an important regulator of the cellular response to oxidative stress. Given that ferroptosis is suppressed by antioxidant defense pathways, such as that involving selenoenzyme glutathione peroxidase 4 (GPX4), we hypothesized that caspase-2 may play a role in regulating ferroptosis. This study provides the first demonstration of an important and unprecedented function of caspase-2 in protecting cancer cells from undergoing ferroptotic cell death. Specifically, we show that depletion of caspase-2 leads to the downregulation of stress response genes including SESN2, HMOX1, SLC7A11, and sensitizes mutant-p53 cancer cells to cell death induced by various ferroptosis-inducing compounds. Importantly, the canonical catalytic activity of caspase-2 is not required for its role and suggests that caspase-2 regulates ferroptosis via non-proteolytic interaction with other proteins. Using an unbiased BioID proteomics screen, we identified novel caspase-2 interacting proteins (including heat shock proteins and co-chaperones) that regulate cellular responses to stress. Finally, we demonstrate that caspase-2 limits chaperone-mediated autophagic degradation of GPX4 to promote the survival of mutant-p53 cancer cells. In conclusion, we document a novel role for caspase-2 as a negative regulator of ferroptosis in cells with mutant p53. Our results provide evidence for a novel function of caspase-2 in cell death regulation and open potential new avenues to exploit ferroptosis in cancer therapy.


Subject(s)
Caspase 2 , Ferroptosis , Caspase 2/genetics , Cell Death/genetics , Molecular Chaperones , Phospholipid Hydroperoxide Glutathione Peroxidase/genetics , Tumor Suppressor Protein p53/genetics , Ferroptosis/genetics
19.
Angew Chem Int Ed Engl ; 63(18): e202402109, 2024 Apr 24.
Article in English | MEDLINE | ID: mdl-38421344

ABSTRACT

This review explores the pivotal role of sulfur in advancing sustainable carbon-carbon (C-C) coupling reactions. The unique electronic properties of sulfur, as a soft Lewis base with significant mesomeric effect make it an excellent candidate for initiating radical transformations, directing C-H-activation, and facilitating cycloaddition and C-S bond dissociation reactions. These attributes are crucial for developing waste-free methodologies in green chemistry. Our mini-review is focused on existing sulfur-directed C-C coupling techniques, emphasizing their sustainability and comparing state-of-the-art methods with traditional approaches. The review highlights the importance of this research in addressing current challenges in organic synthesis and catalysis. The innovative use of sulfur in photocatalytic, electrochemical and metal-catalyzed processes not only exemplifies significant advancements in the field but also opens new avenues for environmentally friendly chemical processes. By focusing on atom economy and waste minimization, the analysis provides broad appeal and potential for future developments in sustainable organic chemistry.

20.
Neurochem Int ; 175: 105703, 2024 May.
Article in English | MEDLINE | ID: mdl-38395151

ABSTRACT

Picrotoxin (PTX), a convulsant of plant origin, has been used in many studies as research tool. PTX is the open channel blocker of the GABAA receptor (GABAAR). Being in the pore, PTX initiates transfer of the channel to the closed state and thus it falls into the "trap". The consequence of this PTX trapping is so-called aftereffect, i.e. continuation of the blockade of the GABA-induced chloride current (IGABA) after removal of PTX from the external solution. The present work shows that the positive allosteric modulators (PAMs) of the GABAA receptor, allopregnanolone (Allo) and zolpidem (Zolp) as well as a high concentration of GABA shortened the PTX aftereffect. Experiments were carried out on isolated Purkinje neurons of the rat cerebellum using the whole-cell patch-clamp method. IGABA was induced by applications of 5 µM GABA (EC30) for 1 s with 30 s intervals. 50 µM PTX completely blocked IGABA, and recovery upon PTX washout occurred with a time constant (τrec) of 20.2 min. 1 µM Allo reduced the blocking effect of PTX by 30% and accelerated the recovery of IGABA by almost 10 times (τrec = 2.4 min). 0.5 µM Zolp did not change the IGABA block in the presence of PTX but accelerated the recovery of IGABA by more than 3 times (τrec = 5.6 min). Increasing the GABA concentration to 20 µM did not change the blocking effect of PTX, but accelerated recovery by 6 times (τrec = 3.3 min). The mechanism of the shortening of the PTX aftereffect is presumably the expansion of the GABAAR pore in the presence of PAMs and a high concentration of the agonist and, as a consequence, the escape of PTX from the "trap". The work describes new pharmacological properties of Allo and Zolp.


Subject(s)
Convulsants , Receptors, GABA-A , Rats , Animals , Picrotoxin/pharmacology , Pregnanolone/pharmacology , gamma-Aminobutyric Acid/pharmacology
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