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1.
Int J Biochem Cell Biol ; 171: 106582, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38649007

RESUMO

DNA methylation is one of the most important epigenetic mark involved in many physiologic cellular processes and pathologies. During mitosis, the transmission of DNA methylation patterns from a mother to the daughter cells is ensured through the action of the Ubiquitin-like, containing PHD and RING domains, 1/DNA methyltransferase 1 (UHRF1/DNMT1) tandem. UHRF1 is involved in the silencing of many tumor suppressor genes (TSGs) via mechanisms that remain largely to be deciphered. The present study investigated the role and the regulation of UHRF1 poly-ubiquitination induced by thymoquinone, a natural anti-cancer drug, known to enhance or re-activate the expression of TSGs. We found that the auto-ubiquitination of UHRF1, induced by TQ, is mediated by reactive oxygen species, and occurs following DNA damage. We demonstrated that the poly-ubiquitinated form of UHRF1 is K63-linked and can still silence the tumor suppressor gene p16INK4A/CDKN2A. We further showed that TQ-induced auto-ubiquitination is mediated via the activity of Tip60. Since this latter is known as a nuclear receptor co-factor, we investigated if the glucocorticoid receptor (GR) might be involved in the regulation of UHRF1 ubiquitination. Activation of the GR, with dexamethasone, did not influence auto-ubiquitination of UHRF1. However, we could observe that TQ induced a K48-linked poly-ubiquitination of GR, probably involved in the proteosomal degradation pathway. Mass-spectrometry analysis of FLAG-HA-tagged UHRF1 identified UHRF1 partners involved in DNA repair and showed that TQ increased their association with UHRF1, suggesting that poly-ubiquitination of UHRF1 is involved in the DNA repair process. We propose that poly-ubiquitination of UHRF1 serves as a scaffold to recruit the DNA repair machinery at DNA damage sites.


Assuntos
Benzoquinonas , Proteínas Estimuladoras de Ligação a CCAAT , Reparo do DNA , Ubiquitina-Proteína Ligases , Ubiquitinação , Humanos , Ubiquitina-Proteína Ligases/metabolismo , Ubiquitina-Proteína Ligases/genética , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Proteínas Estimuladoras de Ligação a CCAAT/genética , Ubiquitinação/efeitos dos fármacos , Benzoquinonas/farmacologia , Reparo do DNA/efeitos dos fármacos , Antineoplásicos/farmacologia , Dano ao DNA/efeitos dos fármacos
2.
Bioorg Chem ; 137: 106616, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37247564

RESUMO

Ubiquitin-like containing PHD and RING finger domain 1 (UHRF1) is a nuclear multi-domain protein overexpressed in numerous human cancer types. We previously disclosed the anthraquinone derivative UM63 that inhibits UHRF1-SRA domain base-flipping activity, although having DNA intercalating properties. Herein, based on the UM63 structure, new UHRF1-SRA inhibitors were identified through a multidisciplinary approach, combining molecular modelling, biophysical assays, molecular and cell biology experiments. We identified AMSA2 and MPB7, that inhibit UHRF1-SRA mediated base flipping at low micromolar concentrations, but do not intercalate into DNA, which is a key advantage over UM63. These molecules prevent UHRF1/DNMT1 interaction at replication forks and decrease the overall DNA methylation in cells. Moreover, both compounds specifically induce cell death in numerous cancer cell lines, displaying marginal effect on non-cancer cells, as they preferentially affect cells with high level of UHRF1. Overall, these two compounds are promising leads for the development of anti-cancer drugs targeting UHRF1.


Assuntos
Proteínas Estimuladoras de Ligação a CCAAT , Neoplasias , Humanos , Proteínas Estimuladoras de Ligação a CCAAT/química , Proteínas Estimuladoras de Ligação a CCAAT/genética , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Metilação de DNA , DNA/química , Modelos Moleculares , Neoplasias/genética
3.
Artigo em Inglês | MEDLINE | ID: mdl-34574455

RESUMO

Eastern herbal medicines (HMs) are plant-derived naturally occurring substances with minimum or no industrial processing that have long been used in traditional medicine. Aflatoxins are frequent contaminants of plants. Therefore, these mycotoxins are likely to contaminate HMs and pose a health risk to individuals using them on a regular basis as preventive or curative treatments of various diseases. The present study aimed to determine aflatoxin levels in the most popular Pakistani HM formulations and to assess the health risk associated with the intake of aflatoxins. A total of 400 samples of HM formulations collected from four districts of Punjab were analyzed for the quantification of aflatoxins, out of which 52.5% were found to be contaminated. The average daily dose (ADD) of AFB1 and AFs through the intake of HM formulations ranged between 0.00483 and 0.118 ng/kg bw/day and between 0.00579 and 1.714 ng/kg bw/day, respectively. The margin of exposure (MOE) and population cancer risk ranged from 99.49 to 29378.8 and from 0.00011 to 0.0325 liver cancer cases/105 individuals/year (0.0075-2.455 liver cancer cases/105 individuals/75 years), respectively. Despite the low exposure to aflatoxins from HM formulations in the four studied Punjab (Pakistan) districts, the frequent contamination of the analyzed samples suggests that official measures should be considered to manage the associated risk.


Assuntos
Aflatoxinas , Neoplasias Hepáticas , Aflatoxinas/análise , Contaminação de Alimentos/análise , Humanos , Paquistão , Medição de Risco
4.
Cureus ; 13(3): e13675, 2021 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-33824826

RESUMO

Novel coronavirus disease 2019 (COVID-19) is known to cause severe bilateral pneumonia and acute respiratory distress syndrome (ARDS), leading to difficulty breathing requiring mechanical ventilation and ICU management. In many patients, it has been found to cause severe hypercoagulability. We present a case of COVID-19 positive patient who developed myocardial infarction (MI) despite being on multiple anticoagulants. A 51-year-old, Middle-Eastern male diabetic patient presented to the emergency room with complaints of sudden onset left leg pain, paresthesias, and swelling for one day. On physical examination, the left leg was cool to touch from forefoot to mid-calf, with noticeable mottling over the forefoot and a nonpalpable dorsalis pedis. The patient was started on therapeutic enoxaparin and diltiazem in ED. Chest X-ray showed bilateral pulmonary infiltrates beginning peripherally and COVID-19 pneumonitis. The patient underwent a mechanical thrombectomy and was loaded with aspirin/clopidogrel, heparin drip, and enoxaparin. Despite being on triple anticoagulation, the patient had new-onset STEMI and elevated troponin levels. On angiography, the patient was found to have occluded mid-left anterior descending, most likely from acute on chronic thrombosis related to the patient's COVID-19 status. As flow could not be re-established, the patient was kept on long-term protective anticoagulation-triple therapy (an oral anticoagulant and dual antiplatelet therapy) and received pulmonary care for COVID-19 infection. The patient was discharged on long-term triple anticoagulation and COVID-19 precautions with scheduled retesting and follow-up.

5.
Sensors (Basel) ; 20(18)2020 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-32911869

RESUMO

This case study provides feasibility analysis of adapting Spiking Neural Networks (SNN) based Structural Health Monitoring (SHM) system to explore low-cost solution for inspection of structural health of damaged buildings which survived after natural disaster that is, earthquakes or similar activities. Various techniques are used to detect the structural health status of a building for performance benchmarking, including different feature extraction methods and classification techniques (e.g., SNN, K-means and artificial neural network etc.). The SNN is utilized to process the sensory data generated from full-scale seven-story reinforced concrete building to verify the classification performances. Results show that the proposed SNN hardware has high classification accuracy, reliability, longevity and low hardware area overhead.

6.
Front Microbiol ; 10: 434, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30972030

RESUMO

Microbial strains with a unique combination of technological and bioactive properties are preferred for industrial applications. The present study was conducted to evaluate the potential use of Enterococcus mundtii QAUEM2808 (NCBI Accession Number: LSMC00000000) in milk fermentation. This strain was isolated from Dahi, an indigenous fermented milk product of South-East Asia. The in vitro study confirmed the acidification ability as well as the proteolytic, cellulolytic, and amylolytic enzyme activities of this strain. It also produced a substantial amount of the folate in laboratory media and no physiological dysfunctions in laboratory animals was observed in feeding trials. All these properties were confirmed by in silico genome analysis. The Enterococcus mundtii QAUEM2808 genome consisted of a single, circular chromosome comprising 2,957,300-bp, 2,587 genes with GC content of 38.5%. Moreover, 16t RNAs, 1, 3 (16S, 23S) rRNAs, 4 ncRNAs, and 91 pseudo genes were also predicted. The majority of genome encode genes for protein, amino acids, carbohydrate, cell wall DNA and RNA metabolisms including all genes required for conversion of lactose to lactic acid. It also exhibited antimicrobial activity against E. coli ATCC 10536, S. aureus ATCC 6538, P. aeruginosa ATCC 9027, and L. monocytogenes ATCC 13932 and was found to be sensitive to commonly used antibiotics. The in silico analysis revealed the presence of genes for mundaticin and enterocin production, and CRISPER regions, however, the genes for antibiotic resistance were absent. No genes related to the pathogenicity island and prophages were detected by genome mining. Therefore, it could be inferened that Enterococcus mundtii QAUEM2808 has the potential to be used in milk fermentation as adjunct culture.

7.
J Pak Med Assoc ; 65(11): 1251-2, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26564308

RESUMO

Takotsubo cardiomyopathy is an acute reversible cardiomyopathy characterised by transient regional left ventricular (LV) motion abnormalities. It is diagnosed on a coronary angiography and left ventriculography. We report the case of a 50-year-old lady who presented with sudden onset of chest pain, with no history of cardiac disease and no risk factors. Remarkably though, she had lost her husband the previous night. Coronary and LV angiography was done which revealed findings typical of takotsubo cardiomyopathy. We report this case for its rarity. Informed consent was taken from the patient before undertaking and reporting this study.


Assuntos
Cardiomiopatia de Takotsubo/diagnóstico por imagem , Angiografia Coronária , Eletrocardiografia , Feminino , Humanos , Pessoa de Meia-Idade , Cardiomiopatia de Takotsubo/etiologia , Cardiomiopatia de Takotsubo/terapia
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