RESUMEN

This is the first successful report on selenium bio-attenuation to satisfy drinking water regulations as per Indian Standards (10 µg/L) in the presence of concomitant nitrate and sulfate from water sources utilizing a fixed bed bioreactor. The bioreactor was immunized with blended microbial culture and worked in downflow mode under anoxic conditions at 30 ± 2 °C for around 190 days under varying influent selenate (100-500 µg/L as selenium), nitrate (50 mg/L), sulfate concentrations (as per selenium removal) and necessary dose of acetic acid (as COD, a carbon source) in synthetic groundwater, operated at an empty bed contact time (EBCT) of 45-120 min. After supplying an adequate dosage of sulfate and alteration of EBCT, selenium was found to comply with drinking water regulations and nitrate was completely removed. X-ray diffraction and transmission electron microscopy analyses depicted nanocrystalline selenium sulfides (SeS and SeS2) formation as the possible mechanisms of selenium removal. Extended toxicity characteristic leaching procedure (TCLP) extractions confirmed a maximum selenium leaching of 52 and 282 µg/L during anoxic and oxic extractions, respectively. Long-term column leaching (>3-month equilibration) under aerobic conditions at pH 7 confirmed the produced precipitate to be essentially stable (∼0.14% Se leaching). This work exhibits the synchronous bioremoval of selenium and its co-anions from contaminated water complying with drinking water standards, and leaving a stable and non-hazardous selenium-laden biosludge.

RESUMEN

ETHNOPHARMACOLOGICAL RELEVANCE: Kidney problems are becoming more common globally and are considered a major health issue in the modern world with high mortality rate. Polyalthia longifolia (Sonn.) Thwaites is a tropical ethnomedicinal plant used to treat various diseases like diabetes, hypertension and urinary disorders and possess antioxidant and anti-inflammatory properties. AIM OF THE STUDY: This study aimed to investigate the phytochemical composition of 70% ethanolic leaf extract of Polyalthia longifolia (Sonn.) Thwaites (PL) and evaluates its nephroprotective effects against cisplatin-induced nephrotoxicity in Wistar rats. MATERIALS AND METHODS: The leaves of PL were extracted with 70% ethanol and performed the phytochemical profiling using Liquid Chromatography-Mass Spectrometry (LC-MS). The nephroprotective effect of PL leaf extract was evaluated at three doses (150, 300 and 600 mg/kg, p.o.) for 14 days against cisplatin toxicity (16 mg/kg, i.p., once) in male Wistar rats. Body and kidney weight indices, kidney function markers and lipid profile markers in serum, and oxidative stress markers in kidney tissue were performed along with the histopathological analysis of kidney. RESULTS: The LC-MS chromatograph confirmed the presence of various phytocompounds include N-Methylhernagine (aporphine alkaloid), 4-Acetamidobutanoic acid (gamma amino acid) and choline, etc. in the PL leaf extract. Exposure of cisplatin (16 mg/kg, i.p., once only) to the animals significantly elevated the levels of kidney functional markers (i.e. serum urea, uric acid, creatinine) and the lipid markers (triglyceride and total cholesterol) in blood circulation with depletion of serum albumin which were reversed by the therapy of PL leaf extract (150, 300 and 600 mg/kg) in dose-dependent manner. The altered level of body and kidney weight in cisplatin treated group was also restored by the therapy. PL leaf extract effectively improved the antioxidant defense system of kidney at all doses by restoring the levels of tissue glutathione, superoxide dismutase, catalase, glutathione peroxidase and glutathione reductase with the dose-dependent reduction of lipid peroxidation against cisplatin-induced renal oxidative stress. The histopathological observations also showed the significant recovery in cellular morphology after PL treatment when compared to the cisplatin toxicity group. The highest dose 600 mg/kg of PL leaf extract showed more pronounced renal recovery (p < 0.001) followed by other two doses, which was similar to the silymarin treatment group (a reference drug) against nephrotoxicity. CONCLUSION: The results of this study revealed the nephroprotective effects of PL leaves against cisplatin-induced nephrotoxicity by reversing the level of biochemical markers and mitigating oxidative stress as well as improving the architecture of renal tissues. This renal protection by PL might be due to the synergistic effect of its phytoconstituents and antioxidant efficacy.

Asunto(s)

Cisplatino , Polyalthia , Ratas , Animales , Cisplatino/toxicidad , Antioxidantes/uso terapéutico , Ratas Wistar , Estrés Oxidativo , Riñón , Etanol/farmacología , Creatinina , Extractos Vegetales/uso terapéutico , Fitoquímicos/farmacología , Fitoquímicos/metabolismo , Lípidos/farmacología

RESUMEN

Mutations within the oncogene KRAS drive an estimated 25% of all cancers. Only allele-specific KRAS G12C inhibitors are currently available and are associated with the emergence of acquired resistance, partly due to upstream pathway reactivation. Given its upstream role in the activation of KRAS, son of sevenless homolog 1 (SOS1), has emerged as an attractive therapeutic target. Agents that target SOS1 for degradation could represent a potential pan-KRAS modality that may be capable of circumventing certain acquired resistance mechanisms. Here, we report the development of two SOS1 cereblon-based bifunctional degraders, BTX-6654 and BTX-7312, cereblon-based bifunctional SOS1 degraders. Both compounds exhibited potent target-dependent and -specific SOS1 degradation. BTX-6654 and BTX-7312 reduced downstream signaling markers, pERK and pS6, and displayed antiproliferative activity in cells harboring various KRAS mutations. In two KRAS G12C xenograft models, BTX-6654 degraded SOS1 in a dose-dependent manner correlating with tumor growth inhibition, additionally exhibiting synergy with KRAS and MEK inhibitors. Altogether, BTX-6654 provided preclinical proof of concept for single-agent and combination use of bifunctional SOS1 degraders in KRAS-driven cancers.

Asunto(s)

Neoplasias , Proteínas Proto-Oncogénicas p21(ras) , Humanos , Proteínas Proto-Oncogénicas p21(ras)/genética , Mutación , Oncogenes , Transducción de Señal

RESUMEN

Polyherbal Unani formulations have been used in the treatment of liver diseases for a long time. (Ibrahim M, Khaja MN, Aara A, Khan AA, Habeeb MA, Devi YP, Narasu ML, Habibullah CM. Hepatoprotective activity of Sapindus mukorossi and Rheum emodi extracts: in vitro and in vivo studies. World J Gastroenterol. 2008:14:2566-2571.) The aim of the present study was to investigate comparative hepatoprotective potential of Majoon-e-Dabeed-ul-ward (MD) and Sharbat-e-Deenar (SD) against CCl4 induced subchronic hepatic toxicity. In vivo study, albino rats were divided into 5 groups. Group I was control; Group II was experimental control treated with CCl4 (0.15 mL/kg, i.p. for 21 days); Groups III-IV treated with SD (2 mL/kg, p.o.) and MD (1,000 mg/kg, p.o.) for 5 days following CCl4 intoxication as in group 2 respectively; and Group V was positive control treated with silymarin (50 mg/kg, p.o.). In vitro hepatoprotective activity of SD and MD (25, 50, and 100 µg/mL) was assessed by SRB assay and flow cytometry analysis. CCl4 exposure significantly elevated the release of hepatic enzymes i.e. AST, ALT, LDH, and SALP in serum and lipid peroxidation in liver tissue which all these parameters were reversed after SD and MD administration. Therapy for 5 days also normalized the levels of antioxidant enzymes i.e. catalase, SOD, GPx, GR, tissue GSH, and aniline hydroxylase in CCl4 treated group. DNA damage and histological alterations caused by CCl4 were restored towards normal group. In vitro study showed protective effect of SD and MD against CCl4 treated HepG2 cell lines and rat hepatocytes. The results suggested that MD has a significant hepatoprotective potential and regulatory effect on oxidative stress than SD against CCl4 induced hepatotoxicity, and that this effect may be related to its antioxidant activity.

RESUMEN

Retinoic acid receptor-related orphan nuclear receptor (ROR) γt is a member of the RORC nuclear hormone receptor family of transcription factors. RORγt functions as a critical regulator of thymopoiesis and immune responses. RORγt is expressed in multiple immune cell populations including Th17 cells, where its primary function is regulation of immune responses to bacteria and fungi through IL-17A production. However, excessive IL-17A production has been linked to numerous autoimmune diseases. Moreover, Th17 cells have been shown to elicit both pro- and anti-tumor effects. Thus, modulation of the RORγt/IL-17A axis may represent an attractive therapeutic target for the treatment of autoimmune disorders and some cancers. Herein we report the design, synthesis and characterization of three selective allosteric RORγt inhibitors in preclinical models of inflammation and tumor growth. We demonstrate that these compounds can inhibit Th17 differentiation and maintenance in vitro and Th17-dependent inflammation and associated gene expression in vivo, in a dose-dependent manner. Finally, RORγt inhibitors were assessed for efficacy against tumor formation. While, RORγt inhibitors were shown to inhibit tumor formation in pancreatic ductal adenocarcinoma (PDAC) organoids in vitro and modulate RORγt target genes in vivo, this activity was not sufficient to delay tumor volume in a KP/C human tumor mouse model of pancreatic cancer.

Asunto(s)

Expresión Génica/efectos de los fármacos , Inflamación/genética , Miembro 1 del Grupo F de la Subfamilia 1 de Receptores Nucleares/antagonistas & inhibidores , Células Th17/efectos de los fármacos , Animales , Carcinogénesis/efectos de los fármacos , Carcinogénesis/genética , Inflamación/metabolismo , Interleucina-17/metabolismo , Ratones , Miembro 1 del Grupo F de la Subfamilia 1 de Receptores Nucleares/metabolismo , Transducción de Señal/efectos de los fármacos , Transducción de Señal/genética , Células Th17/metabolismo

RESUMEN

Co-occurrence of arsenic and nitrate in groundwater sources at a wide range of concentrations is reported. In this work, performance of suspended growth semi-batch reactor was assessed for co-removal of arsenic and nitrate from simulated groundwater to meet the drinking water standards in the absence of iron. The bioreactor was inoculated with mixed bacterial culture and operated in the absence of oxygen for more than 450 days under varying influent arsenate (200-800 µg/L), nitrate concentrations (50-250 mg/L), and hydraulic retention time of 3-6 days. Complete nitrate removal was observed at all tested concentrations. Arsenic removal was found to meet drinking water standards from initial concentrations and up to 600 µg/L. The extended toxicity characteristic leaching procedure leaching experiments indicated that arsenic-laden biosolids would not constitute a hazardous waste. The arsenic leaching was found to increase with an increase in dissolved oxygen and the final leachate concentrations of arsenic were below 150 µg/L. The leaching experiments suggested maintaining non-alkaline conditions for minimum arsenic release from arsenic biosolids formed under sulphidogenic conditions. This study is the first to report that nitrate and arsenic can be simultaneously removed to meet drinking standards in a suspended growth bioreactor.

Asunto(s)

Arsénico , Contaminantes Químicos del Agua , Purificación del Agua , Arsénico/análisis , Reactores Biológicos , Biosólidos , Nitratos , Contaminantes Químicos del Agua/análisis

RESUMEN

The transcriptional coregulator OCA-B promotes expression of T cell target genes in cases of repeated antigen exposure, a necessary feature of autoimmunity. We hypothesized that T cell-specific OCA-B deletion and pharmacologic OCA-B inhibition would protect mice from autoimmune diabetes. We developed an Ocab conditional allele and backcrossed it onto a diabetes-prone NOD/ShiLtJ strain background. T cell-specific OCA-B loss protected mice from spontaneous disease. Protection was associated with large reductions in islet CD8+ T cell receptor specificities associated with diabetes pathogenesis. CD4+ clones associated with diabetes were present but associated with anergic phenotypes. The protective effect of OCA-B loss was recapitulated using autoantigen-specific NY8.3 mice but diminished in monoclonal models specific to artificial or neoantigens. Rationally designed membrane-penetrating OCA-B peptide inhibitors normalized glucose levels and reduced T cell infiltration and proinflammatory cytokine expression in newly diabetic NOD mice. Together, the results indicate that OCA-B is a potent autoimmune regulator and a promising target for pharmacologic inhibition.

Asunto(s)

Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/inmunología , Páncreas/patología , Linfocitos T/inmunología , Transactivadores/metabolismo , Transcripción Genética , Alelos , Secuencia de Aminoácidos , Animales , Autoantígenos/inmunología , Linfocitos T CD4-Positivos/inmunología , Linfocitos T CD8-positivos/inmunología , Cruzamientos Genéticos , Citocinas/metabolismo , Diabetes Mellitus Tipo 1/prevención & control , Modelos Animales de Enfermedad , Femenino , Eliminación de Gen , Células Germinativas/metabolismo , Humanos , Mediadores de Inflamación/metabolismo , Ganglios Linfáticos/metabolismo , Activación de Linfocitos , Masculino , Ratones Endogámicos C57BL , Ratones Endogámicos NOD , Ovalbúmina , Páncreas/metabolismo , Péptidos/farmacología , Receptores de Antígenos de Linfocitos T/metabolismo , Bazo/patología , Transactivadores/deficiencia

RESUMEN

Soaring demand for technology metals (e.g., Cd, Ni) and its ever-depleting primary resources ask for alternative recovery from secondary sources. Ni-Cd battery is one such source that can abridge the gap between demand and supply of such metals. Biogenic recovery, being environmentally benign, is explored for Cd and Ni recovery to manage the menace of spent Ni-Cd battery. Studies with 20, 40 and 60 mg/L Cd2+ initial concentrations in batch mode (in triplicates) at pH 7.0 ± 0.2, 30 ± 0.5 °C and 120 rpm were conducted using sulfate-reducing bacteria for 10 days. Analysis of extracellular polymeric substance revealed that protein secretion was enhanced, thereby forming Cd-EPS binding. Biosolids were collected and freeze-dried for morphological analysis viz. FESEM/EDX, PXRD and TEM, which revealed the formation of CdS nanoparticles (JCPDS card #00-042-1411) in range of 2-6 nm. Similarly, combined effect with 5, 10 and 20 mg/L Ni2+ at 20 mg/L Cd2+ were also investigated. Furthermore, to test the efficacy for real field application, spent Ni-Cd battery was dismantled and its powder was characterized, digested with concentrated HCl at 70 °C and was fed in batch mode after cooling, wherein nanoparticles of Ni and Cd sulfides were formed that has potential as semi-conducting material.

Asunto(s)

Cadmio , Nanopartículas , Matriz Extracelular de Sustancias Poliméricas , Metales , Níquel , Sulfuros

RESUMEN

The present study showed for the first time that selenium, iron, and nitrate could be simultaneously removed in a sulfidogenic bioreactor to meet drinking water standards. A bioreactor inoculated with mixed bacterial consortium was operated for around 330 days in anoxic environment at 30 °C under varying combination of influent selenate (200-1000 µg/L as selenium), and iron (3-10 mg/L) in presence of 50 mg/L of nitrate. Required amount of acetic acid (as carbon source) and sulfate were supplied and the reactor was operated at different empty bed contact time (EBCT) of 45-120 min. Along with complete removal of nitrate, the reactor removed both selenium and iron to meet the drinking water standards. Field emission transmission electron microscopy (FETEM) and X-ray diffraction (XRD) analyses confirmed the formation of selenium sulfide (SeS), achavalite (FeSe) and pyrite (FeS2), which were the possible removal mechanisms of selenium and iron. Thus, this study exhibited that selenium, iron, and nitrate can be simultaneously removed to meet the drinking water standards in a sulfidogenic bioreactor.

Asunto(s)

Agua Potable , Selenio , Contaminantes Químicos del Agua , Purificación del Agua , Reactores Biológicos , Hierro , Nitratos

RESUMEN

The sustainable management of the voluminous waste from drinking water treatment plants has motivated environmental researchers towards several reuse options. Water treatment residues (WTR) are proven adsorbent for remediation of many water- and soil-borne anions (perchlorate, selenium and arsenic), and may be able to remove fluoride from contaminated water. In this study, the sustainable reuse of the freely available waste of the drinking water treatment plants, namely WTR, was explored for their fluoride removal potential to meet drinking water standards. WTR was characterized by specific surface area, Fourier transform infrared (FT-IR), scanning electron microscopy and X-ray powder diffraction (XRD). Batch adsorption experiments were conducted as a function of WTR dose, contact time, agitation speed, initial fluoride concentration, initial temperature and water pH to get best adsorption capacity. About 90% fluoride removal (from initial 5.0 mg/L) was observed within 2 h contact time at WTR dose of 28 g/L. Also, WTR effectively removed fluoride in the pH range of 5-8, whereas removal efficiency decreased at pH 9 or higher. The adsorption equilibrium was established within 120-150 min. Adsorption isotherm data were best fit to Langmuir (R 2 = 0.984) and Freundlich models (R 2 = 0.983), while adsorption kinetic study exhibited that second-order kinetic model was followed with rate constant of 0.038 g/mg min. The FT-IR and XRD analyses affirmed that the metal hydroxyl and metal oxide groups contributed to the fluoride removal. The experimental results show the promising potential of WTR as an adsorbent in fluoride removal from real contaminated groundwater.

Asunto(s)

Agua Potable , Contaminantes Químicos del Agua/análisis , Purificación del Agua , Adsorción , Fluoruros , Concentración de Iones de Hidrógeno , Cinética , Espectroscopía Infrarroja por Transformada de Fourier

RESUMEN

A better understanding of the development and progression of acute myelogenous leukemia (AML) is necessary to improve patient outcome. Here we define roles for the transcription factor Oct1/Pou2f1 in AML and normal hematopoiesis. Inappropriate reactivation of the CDX2 gene is widely observed in leukemia patients and in leukemia mouse models. We show that Oct1 associates with the CDX2 promoter in both normal and AML primary patient samples, but recruits the histone demethylase Jmjd1a/Kdm3a to remove the repressive H3K9me2 mark only in malignant specimens. The CpG DNA immediately adjacent to the Oct1 binding site within the CDX2 promoter exhibits variable DNA methylation in healthy control blood and bone marrow samples, but complete demethylation in AML samples. In MLL-AF9-driven mouse models, partial loss of Oct1 protects from myeloid leukemia. Complete Oct1 loss completely suppresses leukemia but results in lethality from bone marrow failure. Loss of Oct1 in normal hematopoietic transplants results in superficially normal long-term reconstitution; however, animals become acutely sensitive to 5-fluorouracil, indicating that Oct1 is dispensable for normal hematopoiesis but protects blood progenitor cells against external chemotoxic stress. These findings elucidate a novel and important role for Oct1 in AML.

Asunto(s)

Leucemia Mieloide Aguda/genética , Proteínas de Neoplasias/fisiología , Factor 1 de Transcripción de Unión a Octámeros/fisiología , Animales , Médula Ósea/patología , Trastornos de Fallo de la Médula Ósea/etiología , Trastornos de Fallo de la Médula Ósea/genética , Factor de Transcripción CDX2/biosíntesis , Factor de Transcripción CDX2/genética , Transformación Celular Neoplásica/genética , Islas de CpG , Metilación de ADN , Progresión de la Enfermedad , Fluorouracilo/toxicidad , Regulación Leucémica de la Expresión Génica , Células Madre Hematopoyéticas/efectos de los fármacos , Humanos , Histona Demetilasas con Dominio de Jumonji/metabolismo , Leucemia Experimental/genética , Leucemia Experimental/prevención & control , Leucemia Mieloide Aguda/metabolismo , Complejo Desacetilasa y Remodelación del Nucleosoma Mi-2/metabolismo , Ratones Endogámicos C57BL , Factor 1 de Transcripción de Unión a Octámeros/deficiencia , Proteínas de Fusión Oncogénica/fisiología , Regiones Promotoras Genéticas , Quimera por Radiación

RESUMEN

Co-occurrence of arsenic and iron along with nitrate in groundwater makes the trio an onerous combination both in terms of potability and treatment. To meet drinking water guidelines, batch and column laboratory trials were conducted on simulated and bore-well water for attenuation of arsenic (1000 µg/L), iron (5 mg/L) and nitrate (150 mg/L). Increment in sulphate showed a direct individual impact on iron removal, meeting WHO guidelines. The bio-kinetic parameters were in the range of: µmax = 0.079-0.551/d, Ks = 116.18-645.19 mg/L, Kd = 0.0009-0.0077/d and Y = 0.034-0.094 mg MLVSS/mg COD. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) confirmed orpiment precipitation and/or co-precipitation with mackinawite are the key mechanisms for arsenic and iron attenuation. Column experiments were conducted by charging simulated groundwater containing arsenic (500 µg/L), nitrate (50 mg/L), sulphate (25 mg/L) and iron (3 mg/L) in an acetate (105 mg/L as COD) fed flow-through bioreactor at constant empty bed contact time of 60 min. Profile sampling illustrated segregation of different terminal electron accepting zones following thermodynamic yield for sequential removal of different oxyanions. This study showed the importance of considering microbially mediated terminal electron-accepting processes (TEAP) for multi-oxyanion removal in engineered systems.

RESUMEN

Efficiency and feasibility of two backwashing methods (water-nitrogen and water-air assisted) on arsenic and its co-pollutants removal were assessed through running a sulfidogenic attached growth reactor (AGR) treating arsenic spiked simulated groundwater for about 600 days. Replacing water with nitrogen assisted backwashing (WNAB) by water with air assisted backwashing (WAAB) introduced dissolved oxygen (DO) as an additional electron acceptor, which required an increased empty bed contact time (EBCT) to retain the entire terminal electron accepting zones (DO, nitrate, arsenate and sulfate) within the reactor. Removal of arsenic to below 10 µg/L required a longer EBCT at higher influent DO in backwash water. Notably, MiSeq sequencing analysis confirmed the presence of diverse bacterial community on biofilm which can utilize multiple terminal electron acceptors present in the bioreactor.

Asunto(s)

Arsénico/química , Reactores Biológicos/microbiología , Agua Potable , Hierro/química , Nitratos/química , Oxígeno/química , Sulfatos/química , Purificación del Agua/métodos , Aire , Anaerobiosis , Arseniatos/química , Biopelículas , Electrones , Agua Subterránea , Concentración de Iones de Hidrógeno , Nitrógeno/química , Contaminantes Químicos del Agua

RESUMEN

The aim of this work was to study concurrent removal of nitrate, arsenic and iron in an attached growth reactor (AGR) based on bio-sulphidogenesis treating simulated and real-life ground water. A lab-scale bioreactor system was monitored for a period of 511 days under conditions identical to those prevailing at full-scale to assess the relative influence of empty bed contact time (EBCT) (20-90 min), backwash strategies (water-nitrogen and water-air), temperature (20-50 °C), pH (6.6-8.4) and shut down on reactor performance and recovery. Complete removal of nitrate (50 mg/L) and over 95% removal of iron (3 mg/L) occurred. Arsenic removal efficiency was around 99% (500 µg/L) and treated water arsenic concentration was in compliance with the World Health Organization and Indian Standard of 10 µg/L. Port sampling along the depth of bioreactor shows shifting of terminal electron accepting process zones at lower EBCT of 20 min and after air assisted backwashing. The temperature range of 20-50 °C and pH range of 6.6-8.4 were applicable for arsenic removal in natural conditions. Precipitated biosolids were analysed using electron microscopy. Biogenic sulphides resulted in the precipitation of arsenosulphides and iron sulphides, which concurrently removed arsenic and iron. This study suggests that a sulphidogenic bioreactor may help to set the basis for concurrent removal of nitrate, arsenic and iron from real-life groundwater using mixed biofilm bacterial community.

Asunto(s)

Arsénico , Agua Potable , Agua Subterránea , Contaminantes Químicos del Agua , Purificación del Agua , Hierro

RESUMEN

Arsenic is removed from aqueous phase through precipitation as arsenosulphides and/or co-precipitation and adsorption on iron sulphides. Studies were carried out to ascertain the stability of reduced biogenic arsenic and iron sulphide precipitates formed in an attached growth reactor (AGR) through a series of experiments based on Toxicity Characteristic Leaching Procedure (TCLP), aging and long term leaching tests. About half of the AGR was initially added with waste activated carbon (WAC) to support the growth of mixed microbial consortia and used for treatment of arsenic and iron contaminated simulated groundwater. The X-ray diffraction (XRD), X-ray absorption near-edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectroscopy results indicated that the biosolids were mainly composed of arsenosulphides and iron sulphides. While TCLP and aging tests were conducted in anoxic as well as oxic conditions with the aim to evaluate stability of biomass containing biogenic sulphides, long term leaching test was conducted through supply of aerated distilled water to evaluate the stability of spent WAC as well. Results generated from the research indicate that the concentration of leached arsenic never exceeded 123 µg/L under all conditions tested, thus biosolids not imposing an environmental hazard.

Asunto(s)

Arsénico/análisis , Hierro/análisis , Aguas del Alcantarillado/química , Contaminantes Químicos del Agua/análisis , Arsénico/química , Reactores Biológicos , Agua Subterránea , Hierro/química , Oxidación-Reducción , Sulfuros/química

RESUMEN

Embryonic stem cells co-express Oct4 and Oct1, a related protein with similar DNA-binding specificity. To study the role of Oct1 in ESC pluripotency and transcriptional control, we constructed germline and inducible-conditional Oct1-deficient ESC lines. ESCs lacking Oct1 show normal appearance, self-renewal and growth but manifest defects upon differentiation. They fail to form beating cardiomyocytes, generate neurons poorly, form small, poorly differentiated teratomas, and cannot generate chimeric mice. Upon RA-mediated differentiation, Oct1-deficient cells induce lineage-appropriate developmentally poised genes poorly while lineage-inappropriate genes, including extra-embryonic genes, are aberrantly expressed. In ESCs, Oct1 co-occupies a specific set of targets with Oct4, but does not occupy differentially expressed developmental targets. Instead, Oct1 occupies these targets as cells differentiate and Oct4 declines. These results identify a dynamic interplay between Oct1 and Oct4, in particular during the critical window immediately after loss of pluripotency when cells make the earliest developmental fate decisions.

Asunto(s)

Diferenciación Celular , Regulación del Desarrollo de la Expresión Génica , Células Madre Embrionarias de Ratones/fisiología , Factor 1 de Transcripción de Unión a Octámeros/metabolismo , Transcripción Genética , Animales , Ratones , Factor 3 de Transcripción de Unión a Octámeros/metabolismo

RESUMEN

PAS domain containing protein kinase (Pask) is an evolutionarily conserved protein kinase implicated in energy homeostasis and metabolic regulation across eukaryotic species. We now describe an unexpected role of Pask in promoting the differentiation of myogenic progenitor cells, embryonic stem cells and adipogenic progenitor cells. This function of Pask is dependent upon its ability to phosphorylate Wdr5, a member of several protein complexes including those that catalyze histone H3 Lysine 4 trimethylation (H3K4me3) during transcriptional activation. Our findings suggest that, during myoblast differentiation, Pask stimulates the conversion of repressive H3K4me1 to activating H3K4me3 marks on the promoter of the differentiation gene myogenin (Myog) via Wdr5 phosphorylation. This enhances accessibility of the MyoD transcription factor and enables transcriptional activation of the Myog promoter to initiate muscle differentiation. Thus, as an upstream kinase of Wdr5, Pask integrates signaling cues with the transcriptional network to regulate the differentiation of progenitor cells.

Asunto(s)

Código de Histonas , N-Metiltransferasa de Histona-Lisina/metabolismo , Desarrollo de Músculos/fisiología , Músculos/metabolismo , Proteínas Serina-Treonina Quinasas/metabolismo , Transducción de Señal , Animales , Diferenciación Celular , Línea Celular , Regulación de la Expresión Génica , Técnicas de Silenciamiento del Gen , Células HEK293 , N-Metiltransferasa de Histona-Lisina/genética , Humanos , Péptidos y Proteínas de Señalización Intracelular , Ratones , Células Madre Embrionarias de Ratones/metabolismo , Células Musculares/fisiología , Músculo Esquelético , Músculos/lesiones , Proteína MioD/metabolismo , Mioblastos/patología , Miogenina/genética , Miogenina/metabolismo , Fosforilación , Regiones Promotoras Genéticas , Proteínas Serina-Treonina Quinasas/genética , Células Madre , Activación Transcripcional

RESUMEN

Epigenetic changes are crucial for the generation of immunological memory. Failure to generate or maintain these changes will result in poor memory responses. Similarly, augmenting or stabilizing the correct epigenetic states offers a potential method of enhancing memory. Yet the transcription factors that regulate these processes are poorly defined. We find that the transcription factor Oct1 and its cofactor OCA-B are selectively required for the in vivo generation of CD4(+) memory T cells. More importantly, the memory cells that are formed do not respond properly to antigen reencounter. In vitro, both proteins are required to maintain a poised state at the Il2 target locus in resting but previously stimulated CD4(+) T cells. OCA-B is also required for the robust reexpression of multiple other genes including Ifng. ChIPseq identifies ∼50 differentially expressed direct Oct1 and OCA-B targets. We identify an underlying mechanism involving OCA-B recruitment of the histone lysine demethylase Jmjd1a to targets such as Il2, Ifng, and Zbtb32. The findings pinpoint Oct1 and OCA-B as central mediators of CD4(+) T cell memory.

Asunto(s)

Linfocitos T CD4-Positivos/inmunología , Memoria Inmunológica/inmunología , Factor 1 de Transcripción de Unión a Octámeros/inmunología , Transactivadores/inmunología , Animales , Western Blotting , Linfocitos T CD4-Positivos/metabolismo , Células Cultivadas , Expresión Génica/inmunología , Interacciones Huésped-Patógeno/inmunología , Memoria Inmunológica/genética , Interferón gamma/inmunología , Interferón gamma/metabolismo , Interleucina-2/inmunología , Interleucina-2/metabolismo , Histona Demetilasas con Dominio de Jumonji/genética , Histona Demetilasas con Dominio de Jumonji/inmunología , Histona Demetilasas con Dominio de Jumonji/metabolismo , Coriomeningitis Linfocítica/genética , Coriomeningitis Linfocítica/inmunología , Coriomeningitis Linfocítica/virología , Virus de la Coriomeningitis Linfocítica/inmunología , Virus de la Coriomeningitis Linfocítica/fisiología , Ratones Endogámicos C57BL , Ratones Noqueados , Factor 1 de Transcripción de Unión a Octámeros/genética , Factor 1 de Transcripción de Unión a Octámeros/metabolismo , Unión Proteica/inmunología , Proteínas Represoras/genética , Proteínas Represoras/inmunología , Proteínas Represoras/metabolismo , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transactivadores/genética , Transactivadores/metabolismo

RESUMEN

The mechanisms whereby the crucial pluripotency transcription factor Oct4 regulates target gene expression are incompletely understood. Using an assay system based on partially differentiated embryonic stem cells, we show that Oct4 opposes the accumulation of local H3K9me2 and subsequent Dnmt3a-mediated DNA methylation. Upon binding DNA, Oct4 recruits the histone lysine demethylase Jmjd1c. Chromatin immunoprecipitation (ChIP) time course experiments identify a stepwise Oct4 mechanism involving Jmjd1c recruitment and H3K9me2 demethylation, transient FACT (facilitates chromatin transactions) complex recruitment, and nucleosome depletion. Genome-wide and targeted ChIP confirms binding of newly synthesized Oct4, together with Jmjd1c and FACT, to the Pou5f1 enhancer and a small number of other Oct4 targets, including the Nanog promoter. Histone demethylation is required for both FACT recruitment and H3 depletion. Jmjd1c is required to induce endogenous Oct4 expression and fully reprogram fibroblasts to pluripotency, indicating that the assay system identifies functional Oct4 cofactors. These findings indicate that Oct4 sequentially recruits activities that catalyze histone demethylation and depletion.

Asunto(s)

Metilación de ADN/genética , Nucleosomas/metabolismo , Factor 3 de Transcripción de Unión a Octámeros/metabolismo , Células Madre Pluripotentes/metabolismo , Animales , Diferenciación Celular/genética , Células Cultivadas , Inmunoprecipitación de Cromatina/métodos , ADN (Citosina-5-)-Metiltransferasas/genética , Proteínas de Unión al ADN/genética , Proteínas de Unión al ADN/metabolismo , Células Madre Embrionarias/metabolismo , Fibroblastos/metabolismo , Histonas/genética , Histonas/metabolismo , Proteínas de Homeodominio/genética , Proteínas de Homeodominio/metabolismo , Humanos , Histona Demetilasas con Dominio de Jumonji/genética , Histona Demetilasas con Dominio de Jumonji/metabolismo , Ratones , Nucleosomas/genética , Factor 3 de Transcripción de Unión a Octámeros/genética , Regiones Promotoras Genéticas/genética , Secuencias Reguladoras de Ácidos Nucleicos/genética

RESUMEN

This study was designed to evaluate the protective effect of N-acetyl cysteine in reducing methylmercury (MeHg)-induced oxidative stress, lipid peroxidation, DNA damage in liver, kidney, and brain, and their ability to restore altered hepatic, renal, and other biochemical variables. Male Sprague-Dawley rats (150±10 g) were randomly divided into three groups. Group 1 served as the control. Groups 2 and 3 were administered methylmercury (1 mg kg⁻¹ orally, 5 days/week) for 12 weeks, and group 2 served as the experimental control. Group 3 received N-acetyl cysteine (0.6 mg kg⁻¹ intraperitoneally, two days/week) for 12 weeks after methylmercury exposure. Methylmercury exposure caused a significant rise in bilirubin, gamma-glutamyl transpeptidase, protein, triglycerides, cholesterol, urea, creatinine, uric acid, and blood urea nitrogen, with a concomitant decrease in albumin content, reduced glutathione level and acetyl cholinesterase activity, antioxidant enzymes such as glutathione reductase, glutathione peroxidase, glucose-6-phosphate dehydrogenase, and adenosine triphosphatase. However, lipid peroxidation level, metallothionein expression, and DNA damage with increment of tail length were observed after methylmercury intoxication. N-acetyl cysteine, a widely available, nontoxic amino acid derivative, is a promising antioxidant with a wide spectrum of biological functions. The ability of N-acetyl cysteine to enhance mercury excretion and its wide availability in clinical use indicate that it may be an ideal therapeutic agent against methylmercury poisoning.

Asunto(s)

Acetilcisteína/farmacología , Daño del ADN/efectos de los fármacos , Peroxidación de Lípido/efectos de los fármacos , Compuestos de Metilmercurio/toxicidad , Estrés Oxidativo/efectos de los fármacos , Animales , Humanos , Riñón/efectos de los fármacos , Riñón/fisiopatología , Hígado/efectos de los fármacos , Hígado/fisiopatología , Masculino , Ratas , Ratas Sprague-Dawley