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2.
J Drugs Dermatol ; 23(9): 725-728, 2024 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-39231077

RESUMEN

BACKGROUND: Minoxidil is an anti-hypertensive vasodilator increasingly used off-label for the treatment of alopecia. It is associated with an increased risk of pericardial effusions, with recent reports even in patients on low-dose oral minoxidil (LDOM) therapy. OBJECTIVE: To evaluate whether LDOM is associated with increased prevalence of pericardial effusions in patients with alopecia. METHODS: In this cross-sectional study, point-of-care ultrasound was used to screen alopecia patients at dermatology appointments. Scans were evaluated by two independent cardiologists for the presence and size of effusions. The prevalence of effusions was compared between patients on LDOM therapy and patients not on minoxidil therapy. RESULTS: A total of 100 patients were evaluated for pericardial effusion: 51 LDOM patients and 49 control patients. The two groups were similar in terms of age (53.7 vs 54.1; P=0.91), sex (86% vs 73% female; P=0.14), and race. Small pericardial effusions (<1 cm) were identified in 5.8% of LDOM patients and 6% of control patients (P=1), none of which were symptomatic. LIMITATIONS: This is a small, cross-sectional study with limitations on speculation of causality in confirmed cases. CONCLUSION: We did not find evidence of increased prevalence of pericardial effusions in a small group of alopecia patients on LDOM. J Drugs Dermatol. 2024;23(9):725-728. doi:10.36849/JDD.8029.


Asunto(s)
Alopecia , Minoxidil , Derrame Pericárdico , Humanos , Alopecia/diagnóstico , Alopecia/epidemiología , Alopecia/tratamiento farmacológico , Minoxidil/administración & dosificación , Minoxidil/efectos adversos , Femenino , Estudios Transversales , Masculino , Persona de Mediana Edad , Derrame Pericárdico/diagnóstico , Derrame Pericárdico/epidemiología , Prevalencia , Administración Oral , Vasodilatadores/administración & dosificación , Vasodilatadores/efectos adversos , Adulto , Ultrasonografía , Anciano
3.
Int Rev Immunol ; : 1-14, 2024 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-39262163

RESUMEN

The occurrence of incidents involving radiation-combined burn injuries (RCBI) poses a significant risk to public health. Understanding the immunological and physiological responses associated with such injuries is crucial for developing care triage to counter the mortality that occurs due to the synergistic effects of radiation and burn injuries. The core focus of this narrative review lies in unraveling the immune response against RCBI. Langerhans cells, mast cells, keratinocytes, and fibroblasts, which induce innate immunity, have been explored for their response to radiation, burns, and combined injuries. In the case of adaptive immune response, exploring behavioral changes in T regulatory (Treg) cells, T helper cells (Th1, Th2, and Th17), and immunoglobulin results in delayed healing compared to burn and radiation injury. The review also includes the function of complement system components such as neutrophils, acute phase proteins (CRP, C3, and C5), and cytokines for their role in RCBI. Combined insults resulting in a reduction in the cell population of immune cells display variation in response based on radiation doses, burn injury types, and their intrinsic radiosensitivity. The lack of approved countermeasures against RCBI poses a significant challenge. Drug repurposing might help to balance immune cell alteration, resulting in fast recovery and decreasing mortality, which gives it clinical significance for its implication on the site of such incidence. However, the exact immune response in RCBI remains insufficiently explored in pre-clinical and clinical stages, which might be due to the non-availability of in vitro models, standard animal models, or human subjects, warranting further research.


In the realm of public health, RCBI presents significant risks and obstacles. This hazard is quite serious, and it might get worse in the future as evidenced by incidents like nuclear meltdowns and medical mistakes. Diagnosis and treatment become more challenging when serious injuries, particularly burns, are combined with radiation exposure. Features like early shock, poor wound healing, and hematopoietic instability call for advancements in both diagnosis and therapy. Furthermore, the immune system's response to RCBI is complicated and involves changes in cytokine concentrations, immune cell activity, and adaptive immune responses compared to single injuries. Immune cell radiosensitivity varies depending on the type of cell, radiation dose, and length of exposure, so it's important to understand. Repurposing drugs is one of the potential techniques to reduce mortality and speed up healing which are discussed in the manuscript. Still, more research is needed. To effectively tackle RCBI, more investigation into molecular processes, treatment strategy optimization, and information gap closure are essential.

4.
Tissue Cell ; 91: 102563, 2024 Sep 11.
Artículo en Inglés | MEDLINE | ID: mdl-39270512

RESUMEN

Radiation Combined Injuries (RCI) pose formidable public health risks, particularly in the context of nuclear incidents, necessitating specialized treatments and development of biomarkers. RCI encompasses instances where ionizing radiation exposure coincides with burns, wounds, or trauma. However, the limited understanding of cellular responses hinders progress in developing effective therapies. This article underscores the pivotal role of exosomes, nano-sized particles (30-120 nm) actively secreted by cells, in addressing the intricate challenges posed by RCI. Exosomes serve as vehicles for the transportation of bioactive molecules, including proteins, lipids, and miRNA, thereby facilitating processes critical to radiotherapy, burn injury, and wound healing. Exosomes hold significant promise for the transformation of RCI management by reducing inflammation, promoting wound healing, managing sepsis, altering immunological responses, and modulating signal transduction pathways. Moreover, exosomes are also being explored as biomarker for various diseases and stress conditions including radiation exposure and associated injuries. This comprehensive review highlights the burgeoning potential of exosomes in advancing the management of RCI, thereby enhancing public health preparedness and response.

6.
Redox Biol ; 75: 103285, 2024 09.
Artículo en Inglés | MEDLINE | ID: mdl-39128229

RESUMEN

The ability of Mycobacterium tuberculosis (Mtb) to tolerate nitric oxide (•NO) and superoxide (O2•-) produced by phagocytes contributes to its success as a human pathogen. Recombination of •NO and O2•- generates peroxynitrite (ONOO-), a potent oxidant produced inside activated macrophages causing lethality in diverse organisms. While the response of Mtb toward •NO and O2•- is well established, how Mtb responds to ONOO- remains unclear. Filling this knowledge gap is important to understand the persistence mechanisms of Mtb during infection. We synthesized a series of compounds that generate both •NO and O2•-, which should combine to produce ONOO-. From this library, we identified CJ067 that permeates Mtb to reliably enhance intracellular ONOO- levels. CJ067-exposed Mtb strains, including multidrug-resistant (MDR) and extensively drug-resistant (XDR) clinical isolates, exhibited dose-dependent, long-lasting oxidative stress and growth inhibition. In contrast, Mycobacterium smegmatis (Msm), a fast-growing, non-pathogenic mycobacterial species, maintained redox balance and growth in response to intracellular ONOO-. RNA-sequencing with Mtb revealed that CJ067 induces antioxidant machinery, sulphur metabolism, metal homeostasis, and a 4Fe-4S cluster repair pathway (suf operon). CJ067 impaired the activity of the 4Fe-4S cluster-containing TCA cycle enzyme, aconitase, and diminished bioenergetics of Mtb. Work with Mtb strains defective in SUF and IscS involved in Fe-S cluster biogenesis pathways showed that both systems cooperatively protect Mtb from intracellular ONOO- in vitro and inducible nitric oxide synthase (iNOS)-dependent growth inhibition during macrophage infection. Thus, Mtb is uniquely sensitive to intracellular ONOO- and targeting Fe-S cluster homeostasis is expected to promote iNOS-dependent host immunity against tuberculosis (TB).


Asunto(s)
Metabolismo Energético , Homeostasis , Proteínas Hierro-Azufre , Mycobacterium tuberculosis , Oxidación-Reducción , Ácido Peroxinitroso , Mycobacterium tuberculosis/metabolismo , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/efectos de los fármacos , Ácido Peroxinitroso/metabolismo , Proteínas Hierro-Azufre/metabolismo , Proteínas Hierro-Azufre/genética , Humanos , Óxido Nítrico/metabolismo , Estrés Oxidativo , Mycobacterium smegmatis/metabolismo , Mycobacterium smegmatis/genética , Mycobacterium smegmatis/efectos de los fármacos , Superóxidos/metabolismo , Macrófagos/metabolismo , Macrófagos/microbiología , Tuberculosis/microbiología , Tuberculosis/metabolismo
7.
Biochem Biophys Rep ; 39: 101793, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39161580

RESUMEN

Plasminogen activator inhibitor-1 (PAI-1/Serpin E1) is classically known for its antifibrinolytic activity via inhibiting uPA and tPA of the fibrinolytic pathway. PAI-1 has a paradoxical role in tumor progression, and its molecular functions are poorly understood. PAI-1 is a widely accepted secretory protease inhibitor, however, a study suggested the localization of PAI-1 in the cytoplasm and the nucleus. Besides the plethora of its biological functions as a secretory protein, intracellular localization, and functions of PAI-1 remain unexplored at the molecular level. In this study, using various in silico approaches, we showed that PAI-1 possesses a nuclear export signal. Using the CRM1-specific inhibitor leptomycin B, we demonstrated that PAI-1 has a functional CRM1-dependent NES, indicating the possibility of its nuclear localization. Further, we confirm that PAI-1 is localized in the nucleus of endothelial cells using fluorescence microscopy and immunoprecipitation. Notably, we identified an unconventional distribution of PAI-1 in the PML bodies of the nucleus of normal endothelial cells, while the protein was restricted in the cytoplasm of slow-growing cells. The data showed that the localization of PAI-1 in PML bodies is highly correlated with the growth potential of endothelial cells. This conditional nucleocytoplasmic shuttling of PAI-1 during the aging of cells could impart a strong link to its age-related functions and tumor progression. Together, this study identifies the novel behavior of PAI-1 that might be linked with cell aging and may be able to unveil the elusive role of PAI-1 in tumor progression.

8.
Am J Prev Cardiol ; 19: 100707, 2024 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-39113730

RESUMEN

Onjective: Climate change and environmental pollution have known health effects. The recently introduced inflation reduction act (IRA) by the United States government includes funding initiatives to curb climate change, and reduce environmental pollution, in line with the nationally determined contribution (NDC) plan (40-50 % reduction in greenhouse gas [GHG] emissions by 2030, as compared with 2005). The projected cardiovascular health benefits of the IRA driven climate actions to achieve the NDC goals are not known. Methods: We used the Energy Policy Simulator (EPS), a simulation algorithm based on systems dynamics modelling estimating the impact of various energy policies, to model the impact of achieving NDC targets in the United States on health outcomes by 2050. We further investigated race-specific impact on mortality (absolute and relative) by 2050.We estimated the projected reduction in six adverse health outcomes between 2022 and 2050: asthma attacks, non-fatal heart attacks, hospital admissions, respiratory symptoms and bronchitis, lost workdays, and deaths. Results: Achievement of NDC targets by 2050 will result in 987,415 avoided asthma attacks, 41,565 avoided nonfatal heart attacks, 18,993 avoided hospital admissions, 1,493,010 avoided respiratory symptoms and bronchitis, 3,317,250 avoided lost workdays, and 32,659 avoided deaths (22,839 among white individuals, 4993 among Black individuals, 2801 among Asian individuals, and 2026 among other/multirace individuals). By 2050, minority racial groups had higher relative change in avoided deaths (white -0.74 %, Black -1.01 %, Asian -1.24 %, and other/multirace -1.75 %). Similarly, Hispanics/latinos higher relative reductions in deaths (-1.4 %) compared with non-Hispanic/Latinos (-0.7 %) by 2050. Conclusion: The IRA facilitated achievement of NDC GHG reduction goals by 2050 would result in substantial number of avoided adverse health outcomes and death. Racial and ethnic minorities are expected to have the largest relative reductions in deaths by 2050. The current report underscores the importance of continued climate action investment irrespective of political differences. The appreciation of this aspect of the IRA may be more important to overall preservation of health, beyond the reduction in medication costs.

9.
J Drugs Dermatol ; 23(8): 691-693, 2024 08 01.
Artículo en Inglés | MEDLINE | ID: mdl-39093647

RESUMEN

INTRODUCTION: In an effort to define the characteristics of populations affected by melasma, we utilized a large global health research network database from 108 health care organizations (TriNetx) to quantify the associations between race, ethnicity, and comorbidities. METHODS: We identified the cohort of all patients with melasma from the TriNetx database, and subsequently generated a control cohort. ICD-10 codes were used to identify the prevalence of various comorbidities associated with melasma. RESULTS: A total of 41,283 patients with melasma (93% female, mean [SD] age 48.8 [12.6] year) were identified. The most frequently associated risk factors included hypertension (25% of the melasma cohort) and hormonal contraception (24%). Rosacea (OR=5.1), atopic dermatitis (OR=3.3), lupus (OR=2.5), history of skin cancer (OR=2.5), history of internal malignancy (OR=2.1), and hormonal contraception use (OR=2.1) possessed the highest odds ratios for development of melasma (all P< 0.01). A statistically significant association was identified for melasma in Asian or Other/Unknown races (OR=2.0 and OR=1.7, P< 0.01), as well as Hispanic ethnicity (OR=1.3, P< 0.01). White, Black/African American, and Not Hispanic groups all revealed slightly lower odds (all 0.8, P< 0.01). CONCLUSION: This latest global update on the etiopathology of melasma further supports findings from prior epidemiologic study reporting preference in melanized phenotypes (Fitzpatrick skin type III-V), but less so in extreme skin types (I, II, VI). Increased associations with rosacea, atopic dermatitis, and history of cancer may emphasize the importance of treating concurrent inflammatory environments and the consideration of more frequent malignancy surveillance. J Drugs Dermatol. 2024;23(8):691-693.  doi:10.36849/JDD.8233.


Asunto(s)
Comorbilidad , Melanosis , Humanos , Melanosis/epidemiología , Melanosis/etnología , Femenino , Persona de Mediana Edad , Masculino , Adulto , Factores de Riesgo , Prevalencia , Etnicidad/estadística & datos numéricos , Bases de Datos Factuales , Grupos Raciales/estadística & datos numéricos , Rosácea/epidemiología , Rosácea/etnología , Rosácea/diagnóstico , Costo de Enfermedad , Dermatitis Atópica/epidemiología , Dermatitis Atópica/etnología , Estudios de Cohortes
10.
Lasers Surg Med ; 56(7): 625-631, 2024 09.
Artículo en Inglés | MEDLINE | ID: mdl-39010642

RESUMEN

OBJECTIVES: Iatrogenic cutaneous siderosis is a well-recognized dermatologic complication after parenteral iron infusion. The condition manifests as discrete, hyperpigmented patches near the site of injection. Most cases do not resolve spontaneously, leading to significant aesthetic and psychological distress to patients. A recent case of iatrogenic cutaneous siderosis at our institution prompted a systematic review of the efficacy of energy-based devices previously reported in the treatment of this condition. METHODS: PubMed and Cochrane databases were searched for all peer-reviewed articles published using the following search terms: "iron OR heme OR hemosiderosis OR siderosis" and "hyperpigmentation OR staining OR tattoo." Articles reporting on energy-based devices in the treatment of iron-induced hyperpigmentation were included. RESULTS: A total of seven articles and 54 total patients were included in this review. All patients, including the patient treated at our institution, were female, with an average age of 44 years. Hyperpigmentation was most commonly associated with intravenous iron infusion (48/54, 89%), on the arm or forearm (44/54, 81%), and used for the treatment of underlying iron deficiency anemia (54/54, 100%). The application of six different nanosecond or picosecond quality-switched laser systems was reported in the treatment of cutaneous siderosis, with wavelengths ranging from 532 to 1064 nm. Spot sizes varied between 2 and 7 mm, with energy fluences spanning 0.5-40 J/cm2 depending on both the device and spot size. Outcomes were measured after an average of 5.4 laser treatments and 10.4 months, with over half of all reported patients experiencing complete clearance (27/50, 54%). Our patient received treatment in three test areas with picosecond alexandrite 785 nm, nanosecond Nd:YAG 532 nm, and picosecond Nd:YAG 532 nm devices. The nanosecond Nd:YAG 532 nm treated area demonstrated the greatest improvement, and the entire arm was subsequently treated with this device. CONCLUSIONS: Despite the often intractable nature of iatrogenic cutaneous siderosis, laser surgery is a reasonable and safe treatment modality for patients seeking cosmetic improvement of this dyschromia. Dermatologists should be aware of this entity and the efficacy of the energy-based devices currently in our armamentarium. A combination approach may need to be utilized with different wavelengths and pulsed widths to target iron pigment in both dermal and subcutaneous layers.


Asunto(s)
Hiperpigmentación , Humanos , Hiperpigmentación/inducido químicamente , Hiperpigmentación/etiología , Femenino , Hierro/uso terapéutico , Adulto , Láseres de Estado Sólido/uso terapéutico , Anemia Ferropénica/tratamiento farmacológico , Enfermedad Iatrogénica , Terapia por Luz de Baja Intensidad , Siderosis , Terapia por Láser
11.
Environ Geochem Health ; 46(9): 318, 2024 Jul 13.
Artículo en Inglés | MEDLINE | ID: mdl-39001898

RESUMEN

Bell peppers, a globally significant crop, face infestations from various pests. In a study, bell peppers were treated with deltamethrin, ethion, fenazaquin, and fenpropathrin at recommended and double the doses, repeated twice with a 10-day interval. The QuEChERS method underwent validation for linearity, matrix match, accuracy, and precision in bell pepper matrices for residue analysis. The limit of detection for the tested pesticides on bell peppers was 0.01 mg/L, with a quantification limit of 0.05 mg/L. Recovery studies showed a range of 94.80% to 102.80%. Initial deposits of deltamethrin, ethion, fenazaquin, and fenpropathrin on bell peppers at recommended doses were 0.371, 1.237, 0.617, and 0.640 mg/L, respectively, and at double doses were 0.712, 1.945, 1.221, and 1.189 mg/L, respectively. Safe waiting periods of 10, 11, 10, and 8 days were suggested for deltamethrin, ethion, fenazaquin, and fenpropathrin, respectively. The corresponding half-lives for the pesticides were 1.96, 1.79, 2.06, and 1.69 days, all following first-order dissipation kinetics. Dietary risk assessment indicated Hazard Quotients (HQ) below 1 and Theoretical Maximum Daily Intake (TMDI) below Acceptable Daily Intake (ADI) and Maximum Permissible Intake (MPI) levels. Therefore, at their recommended doses, the pesticides were deemed safe for bell pepper cultivation.


Asunto(s)
Capsicum , Contaminación de Alimentos , Insecticidas , Residuos de Plaguicidas , Piretrinas , Capsicum/química , Residuos de Plaguicidas/análisis , Piretrinas/análisis , Contaminación de Alimentos/análisis , Cinética , Medición de Riesgo , Humanos , Nitrilos/toxicidad , Nitrilos/análisis , Exposición Dietética
13.
Biomed Chromatogr ; : e5962, 2024 Jul 16.
Artículo en Inglés | MEDLINE | ID: mdl-39014970

RESUMEN

Residue behaviour and dietary risk assessment of cyantraniliprole, flubendiamide and acetamiprid in broccoli were carried out using the QuEChERS (quick, easy, cheap, effective, rugged and safe) technique coupled with LC-MS/MS. The QuEChERS technique was validated on parameters such as linearity, accuracy, precision, robustness, matrix effects, limit of quantification (LOQ), specificity, retention time and ion ratio as per SANTE (Directorate General for Health and Food Safety) guidelines to attest to the specificity, accuracy and precision of the analytical method in estimating insecticide residues in and on broccoli heads and cropped soil. The LOQ of the method for all three insecticides was 0.01 mg/kg. The initial deposits of cyantraniliprole, flubendiamide and acetamiprid reduced to half of its concentration in 1.873-2.354, 1.975-2.484 and 1.371-1.620 days, respectively. No residues were detected in broccoli-cropped soil at harvest time (30 days after last spray). The proposed maximum residue limits (MRLs) of 1.5, 0.5-0.9 and 2.0-3 mg/kg for cyantraniliprole, flubendiamide and acetamiprid were calculated using the Organisation for Economic Co-operation and Development MRL calculator. The acute and chronic dietary risk assessment of the tested insecticides identified no appreciable dietary risk to the Indian population from the consumption of broccoli heads. The findings of no dietary risk highlight the importance of informed pesticide usage in broccoli and the proposed MRL derived from this study offers crucial guidelines for the regulatory authorities, ensuring the safety of broccoli consumption.

14.
Pediatr Gastroenterol Hepatol Nutr ; 27(4): 258-265, 2024 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-39035405

RESUMEN

Purpose: To date, there is no region-specific guideline for pediatric endoscopy training. This study aimed to illustrate the current status of pediatric endoscopy training in Asia-Pacific region and identify opportunities for improvement. Methods: A cross-sectional survey, using a standardized electronic questionnaire, was conducted among medical schools in the Asia-Pacific region in January 2024. Results: A total of 57 medical centers in 12 countries offering formal Pediatric Gastroenterology training programs participated in this regional survey. More than 75% of the centers had an average case load of <10 cases per week for both diagnostic and therapeutic endoscopies. Only 36% of the study programs employed competency-based outcomes for program development, whereas nearly half (48%) used volume-based curricula. Foreign body retrieval, polypectomy, percutaneous endoscopic gastrostomy, and esophageal variceal hemostasis, that is, sclerotherapy or band ligation (endoscopic variceal sclerotherapy and endoscopic variceal ligation), comprised the top four priorities that the trainees should acquire in the autonomous stage (unconscious) of competence. Regarding the learning environment, only 31.5% provided formal hands-on workshops/simulation training. The direct observation of procedural skills was the most commonly used assessment method. The application of a quality assurance (QA) system in both educational and patient care (Pediatric Endoscopy Quality Improvement Network) aspects was present in only 28% and 17% of the centers, respectively. Conclusion: Compared with Western academic societies, the limited availability of cases remains a major concern. To close this gap, simulation and adult endoscopy training are essential. The implementation of reliable and valid assessment tools and QA systems can lead to significant development in future programs.

17.
bioRxiv ; 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38826263

RESUMEN

Female ticks deposit large egg clusters that range in size from hundreds to thousands. These clusters are restricted to a deposition site, usually under leaf litter and other debris. These sites can be exposed to periodic flooding, where the cluster of tick eggs can float to the surface or remain underneath organic debris entirely underwater. Here, we examined the viability of egg clusters from winter ticks, Dermacentor albipictus , and lone star ticks, Amblyomma americanum , when partially submerged or fully submerged in water in relation to the developmental stages of the eggs. In general, egg clusters that were older and partially submerged had a higher viability than fully submerged, young eggs in water. A. americanum was much more resistant to water exposure between the two species. These studies highlight that egg clusters for specific tick species can remain viable when exposed to water for at least two weeks, where eggs float on the surface. These studies also suggest that water-based distribution of egg clusters could occur for some species, and flooding will differentially impact tick egg survival based on the specific developmental stage of exposure and species.

18.
Sci Rep ; 14(1): 12626, 2024 06 01.
Artículo en Inglés | MEDLINE | ID: mdl-38824223

RESUMEN

This study aims to develop predictive models for rice yield by applying multivariate techniques. It utilizes stepwise multiple regression, discriminant function analysis and logistic regression techniques to forecast crop yield in specific districts of Haryana. The time series data on rice crop have been divided into two and three classes based on crop yield. The yearly time series data of rice yield from 1980-81 to 2020-21 have been taken from various issues of Statistical Abstracts of Haryana. The study also utilized fortnightly meteorological data sourced from the Agrometeorology Department of CCS HAU, India. For comparing various predictive models' performance, evaluation of measures like Root Mean Square Error, Predicted Error Sum of Squares, Mean Absolute Deviation and Mean Absolute Percentage Error have been used. Results of the study indicated that discriminant function analysis emerged as the most effective to predict the rice yield accurately as compared to logistic regression. Importantly, the research highlighted that the optimum time for forecasting the rice yield is 1 month prior to the crops harvesting, offering valuable insight for agricultural planning and decision-making. This approach demonstrates the fusion of weather data and advanced statistical techniques, showcasing the potential for more precise and informed agricultural practices.


Asunto(s)
Oryza , Oryza/crecimiento & desarrollo , Análisis Multivariante , Modelos Logísticos , India , Productos Agrícolas/crecimiento & desarrollo , Agricultura/métodos , Tiempo (Meteorología) , Conceptos Meteorológicos
19.
Biochemistry ; 63(10): 1335-1346, 2024 May 21.
Artículo en Inglés | MEDLINE | ID: mdl-38690768

RESUMEN

Lipoxygenases (LOXs) from pathogenic fungi are potential therapeutic targets for defense against plant and select human diseases. In contrast to the canonical LOXs in plants and animals, fungal LOXs are unique in having appended N-linked glycans. Such important post-translational modifications (PTMs) endow proteins with altered structure, stability, and/or function. In this study, we present the structural and functional outcomes of removing or altering these surface carbohydrates on the LOX from the devastating rice blast fungus, M. oryzae, MoLOX. Alteration of the PTMs did notinfluence the active site enzyme-substrate ground state structures as visualized by electron-nuclear double resonance (ENDOR) spectroscopy. However, removal of the eight N-linked glycans by asparagine-to-glutamine mutagenesis nonetheless led to a change in substrate selectivity and an elevated activation energy for the reaction with substrate linoleic acid, as determined by kinetic measurements. Comparative hydrogen-deuterium exchange mass spectrometry (HDX-MS) analysis of wild-type and Asn-to-Gln MoLOX variants revealed a regionally defined impact on the dynamics of the arched helix that covers the active site. Guided by these HDX results, a single glycan sequon knockout was generated at position 72, and its comparative substrate selectivity from kinetics nearly matched that of the Asn-to-Gln variant. The cumulative data from model glyco-enzyme MoLOX showcase how the presence, alteration, or removal of even a single N-linked glycan can influence the structural integrity and dynamics of the protein that are linked to an enzyme's catalytic proficiency, while indicating that extensive glycosylation protects the enzyme during pathogenesis by protecting it from protease degradation.


Asunto(s)
Proteínas Fúngicas , Lipooxigenasa , Dominio Catalítico , Activación Enzimática , Proteínas Fúngicas/metabolismo , Proteínas Fúngicas/química , Proteínas Fúngicas/genética , Glicosilación , Cinética , Lipooxigenasa/metabolismo , Lipooxigenasa/química , Lipooxigenasa/genética , Modelos Moleculares , Polisacáridos/metabolismo , Polisacáridos/química , Conformación Proteica , Procesamiento Proteico-Postraduccional , Especificidad por Sustrato
20.
J Vis Exp ; (206)2024 Apr 26.
Artículo en Inglés | MEDLINE | ID: mdl-38738900

RESUMEN

Bacterial cytoskeletal proteins such as FtsZ and MreB perform essential functions such as cell division and cell shape maintenance. Further, FtsZ and MreB have emerged as important targets for novel antimicrobial discovery. Several assays have been developed to identify compounds targeting nucleotide binding and polymerization of these cytoskeletal proteins, primarily focused on FtsZ. Moreover, many of the assays are either laborious or cost-intensive, and ascertaining whether these proteins are the cellular target of the drug often requires multiple methods. Finally, the toxicity of the drugs to eukaryotic cells also poses a problem. Here, we describe a single-step cell-based assay to discover novel molecules targeting bacterial cytoskeleton and minimize hits that might be potentially toxic to eukaryotic cells. Fission yeast is amenable to high-throughput screens based on microscopy, and a visual screen can easily identify any molecule that alters the polymerization of FtsZ or MreB. Our assay utilizes the standard 96-well plate and relies on the ability of the bacterial cytoskeletal proteins to polymerize in a eukaryotic cell such as the fission yeast. While the protocols described here are for fission yeast and utilize FtsZ from Staphylococcus aureus and MreB from Escherichia coli, they are easily adaptable to other bacterial cytoskeletal proteins that readily assemble into polymers in any eukaryotic expression hosts. The method described here should help facilitate further discovery of novel antimicrobials targeting bacterial cytoskeletal proteins.


Asunto(s)
Antibacterianos , Proteínas Bacterianas , Proteínas del Citoesqueleto , Schizosaccharomyces , Schizosaccharomyces/efectos de los fármacos , Schizosaccharomyces/metabolismo , Proteínas del Citoesqueleto/metabolismo , Proteínas del Citoesqueleto/antagonistas & inhibidores , Antibacterianos/farmacología , Antibacterianos/química , Proteínas Bacterianas/metabolismo , Evaluación Preclínica de Medicamentos/métodos
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