RESUMEN

Elevated concentrations of arsenic, lithium and boron in drinking water have already been reported in Bolivia. Arsenic is known to cause genotoxicity but that caused by lithium and boron is less well known. The aim of the present cross-sectional study was to evaluate potential genotoxic effects of exposure to arsenic, while considering exposure to lithium and boron and genetic susceptibility. Women (n = 230) were recruited in villages located around Lake Poopó. Exposure to arsenic was determined as the sum of concentrations of arsenic metabolites inorganic arsenic, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) in urine. Exposure to lithium and boron was determined based on their concentrations in urine. Genetic susceptibility was determined by GSTM1 (glutathione S-transferase-mu-1) and GSTT1 (glutathione S-transferase-theta-1) null genotypes and AS3MT (Arsenite Methyltransferase) rs3740393. Genotoxicity was measured in peripheral blood leukocytes using the comet assay. The geometric means of arsenic, lithium, and boron concentrations were 68, 897, and 3972 µg/L, respectively. GSTM1 and GSTT1 null carriers had more DNA strand breaks than gene carriers (p = .008, p = .005). We found no correlation between urinary arsenic and DNA strand breaks (rS = .03, p = .64), and only a weak non-significant positive association in the adjusted multivariate analysis (ß = .09 [-.03; .22], p = .14). Surprisingly, increasing concentrations of lithium in urine were negatively correlated with DNA strand breaks (rS = -.24, p = .0006), and the association persisted in multivariate analysis after adjusting for arsenic (ß = -.22 [-.36; -.08], p = .003). We found no association between boron and DNA strand breaks. The apparent protective effect of lithium merits further investigation.

Asunto(s)

Arsénico , Boro , Agua Potable , Glutatión Transferasa , Litio , Contaminantes Químicos del Agua , Humanos , Estudios Transversales , Femenino , Arsénico/orina , Arsénico/toxicidad , Bolivia , Glutatión Transferasa/genética , Adulto , Litio/orina , Boro/orina , Contaminantes Químicos del Agua/toxicidad , Persona de Mediana Edad , Exposición a Riesgos Ambientales , Daño del ADN/efectos de los fármacos , Ensayo Cometa , Metiltransferasas/genética , Adulto Joven

RESUMEN

BACKGROUND: Cutaneous squamous cell carcinoma (cSCC) develops from epithelial keratinocytes by dysregulation of self-renewal and differentiation. Recent studies have found that the size and number of cSCC tumors gradually decrease or even disappear after HPV vaccination. However, the role of the HPV vaccine in the cSCC mechanism is poorly understood. OBJECTIVE: The aim of this study is to investigate the effect and mechanism of the HPV vaccine in cSCC. METHODS: Immunofluorescence was used to study the immune infiltrating cells in the tumor tissues of patients with cSCC. The effects of the HPV vaccine on cSCC cells and tissues were studied by Cell Culture, Real-time PCR, Western Blot, Cytotoxicity Assay, Enzyme-linked Immunosorbent Assay, m6A Blotting, CCK-8 Assay, m6A Ribonucleic acid Methylation Quantification and tumor transplantation. RESULTS: The HPV vaccine enhanced the toxic effect of CD8+T cells on cSCC cells and promoted the secretion of multiple cytokines by CD8+T cells. In addition, HPV vaccines can increase tumor sensitivity to anti-PD-1 therapy by downregulating METTL3 in tumor tissue, with the combination of HPV vaccine and PD-1 monoclonal antibodies producing enhanced immune cell infiltration compared to PD-1 blockade alone. STUDY LIMITATIONS: It is important to note the limitations of this study, including the small sample size, the construction of the mouse model, and the choice of HPV vaccine and PD-1 monoclonal antibody, which may limit the generalization of our findings to a wider population. CONCLUSIONS: It is hoped that this research will contribute to a deeper understanding of the role of the HPV vaccine in the treatment of cSCC. HPV vaccine is expected to become an important approach to alleviate the development of cSCC.

Asunto(s)

Carcinoma de Células Escamosas , Vacunas contra Papillomavirus , Neoplasias Cutáneas , Animales , Ratones , Humanos , Carcinoma de Células Escamosas/patología , Neoplasias Cutáneas/patología , Vacunas contra Papillomavirus/uso terapéutico , Receptor de Muerte Celular Programada 1 , Inmunoterapia , Metiltransferasas

RESUMEN

BACKGROUND: The involvement of the KMT2 methyltransferase family in the pathogenesis of head and neck squamous cell carcinoma (HNSCC) remains elusive. METHOD: This study adhered to the PRISMA guidelines, employing a search strategy in the LIVIVO, PubMed, Scopus, Embase, Web of Science, and Google Scholar databases. The methodological quality of the studies was assessed by the Joanna Briggs Institute. RESULTS: A total of 33 studies involving 4294 individuals with HNSCC were included in this review. The most important alteration was the high mutational frequency in the KMT2C and KMT2D genes, with reported co-occurrence. The expression of the KMT2D gene exhibited considerable heterogeneity across the studies, while limited data was available for the remaining genes. CONCLUSIONS: KMT2C and KMT2D genes seem to have tumor suppressor activities, with involvement of cell cycle inhibitors, regulating different pathways that can lead to tumor progression, disease aggressiveness, and DNA damage accumulation.

Asunto(s)

Neoplasias de Cabeza y Cuello , Metiltransferasas , Humanos , Carcinoma de Células Escamosas de Cabeza y Cuello/genética , Neoplasias de Cabeza y Cuello/genética , Genes Supresores de Tumor

RESUMEN

In this study, molecular dynamics (MD) and docking simulations were carried out on the crystal structure of Neisseria Gonorrhoeae RsmE aiming at free energy of binding estimation (ΔGbinding) of the methyl transfer substrate S-adenosylmethionine (SAM), as well as its homocysteine precursor S-adenosylhomocysteine (SAH). The mechanistic insight gained was generalized in view of existing homology to two other crystal structures of RsmE from Escherichia coli and Aquifex aeolicus. As a proof of concept, the crystal poses of SAM and SAH were reproduced reflecting a more general pattern of molecular interaction for bacterial RsmEs. Our results suggest that a distinct set of conserved residues on loop segments between ß12, α6, and Met169 are interacting with SAM and SAH across these bacterial methyltransferases. Comparing molecular movements over time (MD trajectories) between Neisseria gonorrhoeae RsmE alone or in the presence of SAH revealed a hitherto unknown gatekeeper mechanism by two isoleucine residues, Ile171 and Ile219. The proposed gating allows switching from an open to a closed state, mimicking a double latch lock. Additionally, two key residues, Arg221 and Thr222, were identified to assist the exit mechanism of SAH, which could not be observed in the crystal structures. To the best of our knowledge, this study describes for the first time a general catalytic mechanism of bacterial RsmE on theoretical ground.

Asunto(s)

Proteínas de Escherichia coli , Metiltransferasas , Metiltransferasas/metabolismo , ARN Ribosómico 16S/genética , Simulación de Dinámica Molecular , Metilación , Escherichia coli/genética , Escherichia coli/metabolismo , S-Adenosilmetionina/metabolismo , Proteínas de Escherichia coli/metabolismo

RESUMEN

Capturing the dynamic and transient interactions of a transcription factor (TF) with its genome-wide targets whose regulation leads to plants' adaptation to their changing environment is a major technical challenge. This is a widespread problem with biochemical methods such as chromatin immunoprecipitation-sequencing (ChIP-seq) which are biased towards capturing stable TF-target gene interactions. Herein, we describe how DNA adenine methyltransferase identification and sequencing (DamID-seq) can be used to capture both transient and stable TF-target interactions by DNA methylation. The DamID technique uses a TF protein fused to a DNA adenine methyltransferase (Dam) from E. coli. When expressed in a plant cell, the Dam-TF fusion protein will methylate adenine (A) bases near the sites of TF-DNA interactions. In this way, DamID results in a permanent, stable DNA methylation mark on TF-target gene promoters, even if the target gene is only transiently "touched" by the Dam-TF fusion protein. Here we provide a step-by-step protocol to perform DamID-seq experiments in isolated plant cells for any Dam-TF fusion protein of interest. We also provide information that will enable researchers to analyze DamID-seq data to identify TF-binding sites in the genome. Our protocol includes instructions for vector cloning of the Dam-TF fusion proteins, plant cell protoplast transfections, DamID preps, library preparation, and sequencing data analysis. The protocol outlined in this chapter is performed in Arabidopsis thaliana, however, the DamID-seq workflow developed in this guide is broadly applicable to other plants and organisms.

Asunto(s)

Arabidopsis , Metilación de ADN , Células Vegetales , Escherichia coli , ADN , Factores de Transcripción , Adenina , Arabidopsis/genética , Factor VII , Metiltransferasas

RESUMEN

Azathioprine (AZA) and 6-mercaptopurine (6-MP) are drugs widely used in the treatment of autoimmune diseases. Among the enzymes involved in the metabolism of AZA and 6-MP are thiopurine methyltransferase (TPMT) and nudix hydrolase 15 (NUDT15). The existence of single nucleotide polymorphisms in the genes that code for these enzymes could decreased enzymatic activity AND lead to severe myelosuppression. The most relevant polymorphism is NUDT15*3 (rs116855232), where the replacement of cytosine for thymine at position 415, which in turn leads to a loss of enzymatic activity. In a previous study, it was identified that together the polymorphisms in the TPMT gene reach an allelic frequency of 3.81%. There is no information regarding the rs116855232 polymorphism in the NUDT15 gene, so this corresponds to the objective of this report. Blood samples from Chilean adult patients with indications for the use of AZA or 6-MP for different pathologies and who had undergone a TPMT gene polymorphism study were retrospectively analyzed. A total of 253 blood samples were analyzed. Of the 253 patients, 47 presented the c.415C>T polymorphism in the NUDT15 gene, 3 being homozygous and 44 heterozygous. Four of the heterozygous patients for NUDT15 also had the *3A variant in the TPMT gene, also heterozygous. The allelic frequency of the minor T allele found (9.88%) was very similar to that found in patients of Asian origin, and much higher than that reported for the European Caucasian or Latin American population.

Asunto(s)

Azatioprina , Mercaptopurina , Metiltransferasas , Pirofosfatasas , Adulto , Humanos , Azatioprina/efectos adversos , Chile , Mercaptopurina/efectos adversos , Metiltransferasas/genética , Polimorfismo de Nucleótido Simple , Pirofosfatasas/genética , Estudios Retrospectivos

RESUMEN

Cardiac fibrosis is known as the expansion of the cardiac interstitium through excessive deposition of extracellular matrix proteins; this process is performed by a multifunctional cell known as the cardiac fibroblast. After the myocardial injury, these cells are activated as a repair program, increase, and switch to a contractile phenotype, which is evidenced by an increase in alpha- smooth muscle actin. Likewise, there is an increase in type I and III collagen, which are considered profibrotic biomarkers. It is believed that one of the proteins involved in cardiac remodeling is METTL3, which is the enzyme responsible for N6-methyladenosine (m6A) methylation, the most common and abundant epigenetic modification of eukaryotic mRNA. This review focuses on recent studies in which the possible role of METTL3 in the progression of fibrosis has been demonstrated, mainly in cardiac fibrogenesis.

Asunto(s)

Colágeno , Epigénesis Genética , Humanos , Metilación , Fibrosis , Colágeno/metabolismo , Fibroblastos , Metiltransferasas/metabolismo

RESUMEN

OBJECTIVES: N6-Methyladenosine (m6A) modification plays a vital role in lung disorders. However, the potential of m6A in neonatal Bronchopulmonary Dysplasia (BPD) has not been reported. This study aimed to investigate the roles of METTL3 in BPD. METHODS: BPD models were established by hyperoxia in vivo and in vitro. Histological analysis was determined using HE staining. Gene expression was determined using Western blotting, qRT-PCR, and immunofluorescence. The release of IL-1ß and IL-18 was detected using ELISA. The m6A sites of ATG8 were predicted by SCRAPM and verified by MeRIP assay. The location of GSDMD and ATG8 was determined by FISH assay. The interaction between ATG8 and GSDMD was detected using Coimmunoprecipitation (Co-IP). Cell pyroptosis was determined using flow cytometry and TUNEL assays. RESULTS: METTL3 was overexpressed in BPD, which was accompanied by an increase in m6A levels. Interestingly, METTL3 suppressed hyperoxia-mediated damage and pyroptosis in BEAS-2B cells and promoted cell autophagy. METTL3-mediated m6A modification of ATG8 suppressed its expression and disrupted the interaction between ATG8 and GSDMD. However, autophagy inhibition induced pyroptosis in BEAS-2B cells. In vivo assays showed that METTL3-mediated autophagy inhibition induced a decrease in the radial alveolar count and an increase in the mean linear intercept and promoted cell pyroptosis. CONCLUSION: In conclusion, METTL3-mediated cell pyroptosis promotes BPD by regulating the m6A modification of ATG8. This may provide new insight into the development of BPD.

Asunto(s)

Displasia Broncopulmonar , Hiperoxia , Humanos , Recién Nacido , Autofagia , Hiperoxia/complicaciones , Hiperoxia/metabolismo , Hiperoxia/patología , Metiltransferasas , Piroptosis

RESUMEN

BACKGROUND: The tumor microenvironment plays a crucial role in the oncogenesis and treatment of diffuse large B-cell lymphoma (DLBCL). The H3K9me3-specific histone methyltransferase Suppressor of variegation 3-9 homolog 1 (SUV39H1) is a significant gene that promotes the progression of various malignancies. However, the specific expression of SUV39H1 in DLBCL remains unclear. METHODS: By retrieving data from GEPIA, UCSC XENA and TCGA public databases, we observed the high expression of SUV39H1 in DLBCL. Combined with an immunohistochemical validation assay, we analyzed our hospital's clinical characteristics and prognosis of 67 DLBCL patients. The results showed that high SUV39H1 expression was closely associated with age over 50 years (P = 0.014) and low albumin levels (P = 0.023) of patients. Furthermore, the experiments in vitro were deployed to evaluate the regulation of SUV39H1 on the DLBCL immune microenvironment. RESULTS: The results showed that high SUV39H1 expression was closely associated with age over 50 years (P = 0.014) and low albumin levels (P = 0.023) of patients. The prognostic analysis showed that the high SUV39H1 expression group had a lower disease-free survival (DFS) rate than the low SUV39H1 expression group (P < 0.05). We further discovered that SUV39H1 upregulated the expression of CD86+ and CD163+ tumor-associated macrophages by DLBCL patients' tissues and cell experiments in vitro (P < 0.05). And SUV39H1-associated T lymphocyte subsets and cytokines IL-6/CCL-2 were downregulated in DLBCL (P < 0.05). CONCLUSIONS: In summary, SUV39H1 might be not only a potential target for treating DLBCL but also a clinical indicator for doctors to evaluate the trend of disease development.

Asunto(s)

Linfoma de Células B Grandes Difuso , Humanos , Persona de Mediana Edad , Pronóstico , Linfoma de Células B Grandes Difuso/tratamiento farmacológico , Subgrupos de Linfocitos T/metabolismo , Subgrupos de Linfocitos T/patología , Citocinas/metabolismo , Albúminas/uso terapéutico , Microambiente Tumoral , Metiltransferasas/metabolismo , Proteínas Represoras/metabolismo

RESUMEN

Background: The presence of polymorphisms in the TPMT gene is associated with adverse effects in patients treated with standard doses of thiopurine drugs. Scientific evidence recognizes significant ethnic differences in their frequencies and how their early identification can prevent clinical complications. Methods: 150 healthy residents of Aragua, Venezuela were enrolled. The SNPs c.460G>A and c.719A>G were detected by PCR-restriction fragment length polymorphism assay and c.238G>C by allele-specific PCR. Results: All genotype polymorphisms were heterozygous. TPMT*1/*3A, TPMT*1/*3C and TPMT*1/*2 genotypes were found in 4.0, 2.0 and 0.7%, respectively. Conclusion: 6.7% of individuals have an intermediate TPMT activity. These findings support the importance of prior genotyping of TPMT in Venezuelan patients who require thiopurine drug therapy.

Asunto(s)

Metiltransferasas , Polimorfismo de Nucleótido Simple , Humanos , Alelos , Frecuencia de los Genes/genética , Genotipo , Heterocigoto , Metiltransferasas/genética , Polimorfismo de Nucleótido Simple/genética , Venezuela

RESUMEN

Emerging and/or re-emerging viral diseases such as dengue and Zika are a worldwide concern. Therefore, new antiviral therapeutics are necessary. In this sense, a non-structural protein with methyltransferase (MTase) activity is an attractive drug target because it plays a crucial role in dengue and Zika virus replication. Different drug strategies such as virtual screening, molecular docking, and molecular dynamics have identified new inhibitors that bind on the MTase active site. Therefore, in this review, we analyze MTase inhibitors, including S-adenosyl-L-methionine (SAM), S-adenosyl-l-homocysteine (SAH) and guanosine-5'-triphosphate (GTP) analogs, nitrogen-containing heterocycles (pyrimidine, adenosine, and pyridine), urea derivatives, and natural products. Advances in the design of MTase inhibitors could lead to the optimization of a possible single or broad-spectrum antiviral drug against dengue and Zika virus.

Asunto(s)

Arbovirus , Dengue , Infección por el Virus Zika , Virus Zika , Humanos , Simulación del Acoplamiento Molecular , Arbovirus/metabolismo , Proteínas no Estructurales Virales , Antivirales/química , Metiltransferasas , Dengue/tratamiento farmacológico , Infección por el Virus Zika/tratamiento farmacológico

RESUMEN

BACKGROUND: Long noncoding RNA (lncRNAs) GMDS-AS1 has been reported as a tumor regulator in tumor growth and metastasis, but its effect in hepatocellular carcinoma (HCC) remains unclear. ESET, a histone H3K9 methyl-transferase, is involved in epigenomic regulation of tumor progression in multiple cancers. However, the correlation between ESET and lncRNA in HCC is less reported. METHODS: Quantitative real-time PCR (qRT-PCR) was taken to determine the expression of ESET and GMDS-AS1. Western blot was taken to determine the target protein levels of ESET and GMDS-AS1. Online database and bioinformatics analysis were used to screen abnormally expressed genes. Luciferase assay was performed to confirm the binding of GMDS-AS1 and PSMB1. Ki67 and Edu were used for evaluated the proliferation of tumor cells. ChIP assay was performed to verify the relationship between H3K9me1 and lncRNA GMDS-AS1 promoter. Transwell was taken to determine the migration and invasion ability of tumor cells. CCK-8 was used for determining the viability of tumor cells. Flow cytometry was performed to detect the cell cycle of tumor cells. RESULTS: The expression of GMDS-AS1 was decreased and the expression of ESET was increased in HCC. GMDS-AS1 inhibition contributed to tumor development, and this effect was closely related to epigenetic inhibition of GMDS-AS1 by ESET. PSMB1, a downstream target of GMDS-AS1, promoted the tumor proliferation and was negatively regulated by GMDS-AS1. CONCLUSION: Our result demonstrates anti-tumorigenic traits of lncRNA GMDS-AS1 in HCC and explains its pattern of regulation mediated by ESET. Our work unmasked an essential role of GMDS-AS1 in HCC progression and detected a novel pathway for ESET to promote HCC.

Asunto(s)

Carcinoma Hepatocelular , Neoplasias Hepáticas , MicroARNs , ARN Largo no Codificante , Humanos , Carcinoma Hepatocelular/patología , ARN Largo no Codificante/genética , ARN Largo no Codificante/metabolismo , Neoplasias Hepáticas/patología , Supervivencia Celular , Metiltransferasas/genética , Epigenómica , Proliferación Celular/genética , MicroARNs/genética , Epigénesis Genética , Regulación Neoplásica de la Expresión Génica , Línea Celular Tumoral , Movimiento Celular/genética

RESUMEN

Since late 2016, a yellow fever virus (YFV) variant carrying a set of nine amino acid variations has circulated in South America. Three of them were mapped on the methyltransferase (MTase) domain of viral NS5 protein. To assess whether these changes affected viral infectivity, we synthesized YFV carrying the MTase of circulating lineage as well as its isoform with the residues of the previous strains (NS5 K101R, NS5 V138I, and NS5 G173S). We observed a slight difference in viral growth properties and plaque phenotype between the two synthetic YFVs. However, the MTase polymorphisms associated with the Brazilian strain of YFV (2016-2019) confer more susceptibility to the IFN-I. In addition, in vitro MTase assay revealed that the interaction between the YFV MTase and the methyl donor molecule (SAM) is altered in the Brazilian MTase variant. Altogether, the results reported here describe that the MTase carrying the molecular signature of the Brazilian YFV circulating since 2016 might display a slight decrease in its catalytic activity but virtually no effect on viral fitness in the parameters comprised in this study. The most marked influence of these residues stands in the immune escape against the antiviral response mediated by IFN-I.

Asunto(s)

Interferón Tipo I , Virus de la Fiebre Amarilla , Virus de la Fiebre Amarilla/fisiología , Interferón Tipo I/genética , Aminoácidos , Evasión Inmune , Brasil , Metiltransferasas/metabolismo , Proteínas no Estructurales Virales/genética

RESUMEN

PURPOSE: Patients diagnosed with cancer often suffer from emotional stressors, such as anxiety, depression, and fear of death. However, whether fear stress could influence the glioma progression is still unclear. METHODS: Xenograft glioma animal models were established in nude mice. Tumor-bearing mice were subjected to fear stress by living closely with cats and then their depressive behaviors were measured using an open field test. Hematoxylin and eosin staining, the TUNEL staining and immunochemical staining were used to detect the histopathological changes of tumor tissues. Gene expression profiling was used to screen the aberrant gene expression. Methylated RNA immunoprecipitation was used to identify the RNA m6A level. Gene expression was measured by western blot and real-time PCR, respectively. RESULTS: We found that fear stress promoted glioma tumor progression in mice. Fear stress-induced upregulation of METTL3 and FSP1, increased m6A level of glioma tumor tissues, and inhibited ferroptosis in glioma progression, which were reversed by knockdown of METTL3 and FSP1 in vivo. In addition, we found that when iFSP1 (a ferroptosis inducer by targeting inhibition of FSP1) was introduced to glioma cells, the cells viability of glioma significantly was decreased and ferroptosis was enhanced in glioma cells. CONCLUSIONS: Fear stress-induced upregulation of METTL3 stabilized FSP1 mRNA by m6A modification, leading to tumor progression through inhibition of ferroptosis. Our study provides a new understanding of psychological effects on glioma development, and new insights for glioma therapy.

Asunto(s)

Miedo , Ferroptosis , Glioma , Estrés Psicológico , Animales , Humanos , Ratones , Línea Celular Tumoral , Depresión/etiología , Depresión/genética , Depresión/psicología , Modelos Animales de Enfermedad , Miedo/fisiología , Miedo/psicología , Ferroptosis/genética , Ferroptosis/fisiología , Expresión Génica , Glioma/genética , Glioma/psicología , Metiltransferasas/genética , Ratones Desnudos , ARN Mensajero , Estrés Psicológico/etiología , Estrés Psicológico/genética , Estrés Psicológico/psicología , Regulación hacia Arriba/genética

RESUMEN

Coronavirus disease (COVID-19) has the virus that causes the SARS-CoV-2 severe acute respiratory syndrome, which has reached a pandemic proportion, with thousands of deaths worldwide already registered. It has no standardized effective clinical treatment, arousing the urgent need for the discovery of bioactive compounds for the treatment of symptoms of COVID-19. In this context, the present study aimed to evaluate the influence of seasonality on the yield and chemical composition of the essential oils of Piper cernuum and Piper rivinoides as well as to evaluate the anti-SARS-CoV-2 potential of the major components of each oil by molecular docking and quantum chemical calculation (Density Functional Theory method), being possible indicate that the winter and autumn periods, the seasons of the year where it is possible to obtain the highest percentage of Piper cernuum and Piper rivinoides oils, respectively. Regarding the anti-SARS-Cov-2 potential, the present work showed that the dihydroagarofuran present in Piper cernuum, presented a strong interaction with amino acid residues from Mpro, presenting a potential similar to Remdesivir, a drug for clinical use. Regarding methyltransferase, dihydroagarofuran (Piper cernuum) and myristicin (Piper rivinoids) showed better affinity, with important interactions at the active site of the inhibitor Sinefugin, suggesting a potential inhibitory effect of the heterodimer methyltransferase complex NSP16-NSP10 SARS Cov-2. Molecular docking and molecular dynamics studies represent an initial step, being indicative for future in vitro studies of dihydroagarofuran and myristicin, as possible pharmacological tools for COVID-19.Communicated by Ramaswamy H. Sarma.

Asunto(s)

COVID-19 , Aceites Volátiles , Piper , Humanos , Simulación del Acoplamiento Molecular , SARS-CoV-2/metabolismo , Metiltransferasas/química , Estaciones del Año , Teoría Funcional de la Densidad , Aceites Volátiles/farmacología , Aceites Volátiles/química , Piper/química , Simulación de Dinámica Molecular , Inhibidores de Proteasas

RESUMEN

The application of chalcogenonium salts in organic synthesis has grown enormously in the past decades since the discovery of the methyltransferase enzyme cofactor S-adenosyl-L-methionine (SAM), featuring a sulfonium center as the reactive functional group. Chalcogenonium salts can be employed as alkylating agents, sources of ylides and carbon-centered radicals, partners for metal-catalyzed cross-coupling reactions and organocatalysts. Herein, we will focus the discussion on heavier chalcogenonium salts (selenonium and telluronium), presenting their utility in synthetic organic transformations and, whenever possible, drawing comparisons in terms of reactivity and selectivity with the respective sulfonium analogues.

Asunto(s)

Metiltransferasas , Sales (Química) , S-Adenosilmetionina , Coenzimas

RESUMEN

BACKGROUND: Valproic acid/sodium valproate (VPA), a well-known anti-epileptic agent, inhibits histone deacetylases, induces histone hyperacetylation, promotes DNA demethylation, and affects the histone methylation status in some cell models. Histone methylation profiles have been described as potential markers for cervical cancer prognosis. However, histone methylation markers that can be studied in a cervical cancer cell line, like HeLa cells, have not been investigated following treatment with VPA. METHODS: In this study, the effect of 0.5 mM and 2.0 mM VPA for 24 h on H3K4me2/me3, H3K9me/me2 and H3K27me/me3 signals as well as on KMT2D, EZH2, and KDM3A gene expression was investigated using confocal microscopy, Western blotting, and RT-PCR. Histone methylation changes were also investigated by Fourier-transform infrared spectroscopy (FTIR). RESULTS: We found that VPA induces increased levels of H3K4me2/me3 and H3K9me, which are indicative of chromatin activation. Particularly, H3K4me2 markers appeared intensified close to the nuclear periphery, which may suggest their implication in increased transcriptional memory. The abundance of H3K4me2/me3 in the presence of VPA was associated with increased methyltransferase KMT2D gene expression. VPA induced hypomethylation of H3K9me2, which is associated with gene silencing, and concomitant with the demethylase KDM3A, it increased gene expression. Although VPA induces increased H3K27me/me3 levels, it is suggested that the role of the methyltransferase EZH2 in this context could be affected by interactions with this drug. CONCLUSION: Histone FTIR spectra were not affected by VPA under present experimental conditions. Whether our epigenetic results are consistent with VPA affecting the aggressive tumorous state of HeLa cells, further investigation is required.

Asunto(s)

Metilación de ADN , Histonas , Neoplasias del Cuello Uterino , Ácido Valproico , Femenino , Humanos , Células HeLa , Histonas/metabolismo , Histona Demetilasas con Dominio de Jumonji/genética , Histona Demetilasas con Dominio de Jumonji/metabolismo , Lisina/metabolismo , Metiltransferasas , Neoplasias del Cuello Uterino/tratamiento farmacológico , Neoplasias del Cuello Uterino/genética , Ácido Valproico/farmacología , Ácido Valproico/uso terapéutico

RESUMEN

DNA methylation is a key epigenetic modification to regulate gene expression in mammalian cells. Abnormal DNA methylation in gene promoters is common across human cancer types. DNMT3B is the main de novo methyltransferase enhanced in several primary tumors. How de novo methylation is established in genes related to cancer is poorly understood. CpG islands (CGIs), common sequences, and transcription factors (TFs) that interact with DNMT3B have been associated with abnormal de novo methylation. We initially identified cis elements associated with DNA methylation to investigate the contribution of DNMT3B overexpression to the deregulation of its possible target genes in an epithelial cell model. In a set of downregulated genes (n = 146) from HaCaT cells with DNMT3B overexpression, we found CGI, common sequences, and TFs Binding Sites that interact with DNMT3B (we called them P-down-3B). PPL1, VAV3, IRF1, and BRAF are P-down-3B genes that are downregulated and increased their methylation in DNMT3B presence. Together these findings suggest that methylated promoters aberrantly have some cis elements that could conduce de novo methylation by DNMT3B.

Asunto(s)

Metilación de ADN , Epigénesis Genética , Humanos , Animales , Islas de CpG , Sitios de Unión , Metiltransferasas , Mamíferos

RESUMEN

Methyltransferases (MTases) enzymes, responsible for RNA capping into severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are emerging important targets for the design of new anti-SARS-CoV-2 agents. Here, analogs of S-adenosylmethionine (SAM), obtained from the bioisosteric substitution of the sulfonium and amino acid groups, were evaluated by rigorous computational modeling techniques such as molecular dynamics (MD) simulations followed by relative binding free analysis against nsp16/nsp10 complex from SARS-CoV-2. The most potent inhibitor (2a) shows the lowest binding free energy (-58.75 Kcal/mol) and more potency than Sinefungin (SFG) (-39.8 Kcal/mol), a pan-MTase inhibitor, which agrees with experimental observations. Besides, our results suggest that the total binding free energy of each evaluated SAM analog is driven by van der Waals interactions which can explain their poor cell permeability, as observed in experimental essays. Overall, we provide a structural and energetic analysis for the inhibition of the nsp16/nsp10 complex involving the evaluated SAM analogs as potential inhibitors.

Asunto(s)

Tratamiento Farmacológico de COVID-19 , S-Adenosilmetionina , Humanos , S-Adenosilmetionina/farmacología , S-Adenosilmetionina/metabolismo , SARS-CoV-2 , Proteínas no Estructurales Virales/metabolismo , Metiltransferasas/metabolismo

RESUMEN

BACKGROUND: Xenotransplantation has been primarily performed using fresh donor tissue to study testicular development for about 20 years, and whether the cultured tissue would be a suitable donor is unclear. In this study, we combined testicular culture and xenotransplantation into an integrative model and explored whether immature testicular tissue would survive and continue to develop in this model. METHODS: In the new integrative model group, the testes of neonatal rats on postnatal day 8 (PND 8) were cultured for 4 days ex vivo and then were transplanted under the dorsal skin of castrated nude mice. The xenografted testes were resected on the 57th day after xenotransplantation and the testes of rats in the control group were harvested on PND 69. The survival state of testicular tissue was evaluated from morphological and functional perspectives including H&E staining, immunohistochemical staining of 8-OH-dG, immunofluorescence staining, TUNEL assay, ultrastructural study, gene expression and protein analysis. RESULTS: (a) We found that complete spermatogenesis was established in the testes in the new integrative model group. Compared with the control in the same stage, the seminiferous epithelium in some tubules was a bit thinner and there were vacuoles in part of the tubules. Immunofluorescence staining revealed some ACROSIN-positive spermatids were present in seminiferous tubule of xenografted testes. TUNEL detection showed apoptotic cells and most of them were germ cells in the new integrative model group. 8-OH-dG immunohistochemistry showed strongly positive-stained in the seminiferous epithelium after xenotransplantation in comparison with the control group; (b) Compared with the control group, the expressions of FOXA3, DAZL, GFRα1, BOLL, SYCP3, CDC25A, LDHC, CREM and MKI67 in the new integrative model group were significantly elevated (P < 0.05), indicating that the testicular tissue was in an active differentiated and proliferative state; (c) Antioxidant gene detection showed that the expression of Nrf2, Keap1, NQO1 and SOD1 in the new integrative model group was significantly higher than those in the control group (P < 0.05), and DNA methyltransferase gene detection showed that the expression of DNMT3B was significantly elevated as well (P < 0.05). CONCLUSION: The new integrative model could maintain the viability of immature testicular tissue and sustain the long-term survival in vivo with complete spermatogenesis. However, testicular genes expression was altered, vacuolation and thin seminiferous epithelium were still apparent in this model, manifesting that oxidative damage may contribute to the testicular development lesion and it needs further study in order to optimize this model.

Asunto(s)

Factor 2 Relacionado con NF-E2 , Testículo , 8-Hidroxi-2'-Desoxicoguanosina , Acrosina/metabolismo , Animales , Antioxidantes/metabolismo , Proteína 1 Asociada A ECH Tipo Kelch/metabolismo , Masculino , Metiltransferasas/metabolismo , Ratones , Ratones Desnudos , Factor 2 Relacionado con NF-E2/metabolismo , Ratas , Espermatogénesis , Superóxido Dismutasa-1/metabolismo , Testículo/metabolismo