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1.
PLoS Biol ; 21(8): e3002231, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37590294

RESUMO

Mycobacterium tuberculosis (Mtb) defends host-mediated killing by repressing the autophagolysosome machinery. For the first time, we report NCoR1 co-repressor as a crucial host factor, controlling Mtb growth in myeloid cells by regulating both autophagosome maturation and lysosome biogenesis. We found that the dynamic expression of NCoR1 is compromised in human peripheral blood mononuclear cells (PBMCs) during active Mtb infection, which is rescued upon prolonged anti-mycobacterial therapy. In addition, a loss of function in myeloid-specific NCoR1 considerably exacerbates the growth of M. tuberculosis in vitro in THP1 differentiated macrophages, ex vivo in bone marrow-derived macrophages (BMDMs), and in vivo in NCoR1MyeKO mice. We showed that NCoR1 depletion controls the AMPK-mTOR-TFEB signalling axis by fine-tuning cellular adenosine triphosphate (ATP) homeostasis, which in turn changes the expression of proteins involved in autophagy and lysosomal biogenesis. Moreover, we also showed that the treatment of NCoR1 depleted cells by Rapamycin, Antimycin-A, or Metformin rescued the TFEB activity and LC3 levels, resulting in enhanced Mtb clearance. Similarly, expressing NCoR1 exogenously rescued the AMPK-mTOR-TFEB signalling axis and Mtb killing. Overall, our data revealed a central role of NCoR1 in Mtb pathogenesis in myeloid cells.


Assuntos
Mycobacterium tuberculosis , Correpressor 1 de Receptor Nuclear , Animais , Humanos , Camundongos , Proteínas Quinases Ativadas por AMP , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos , Leucócitos Mononucleares , Células Mieloides , Serina-Treonina Quinases TOR , Correpressor 1 de Receptor Nuclear/metabolismo
2.
J Immunol ; 209(10): 1930-1941, 2022 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-36426944

RESUMO

The antiviral state, an initial line of defense against viral infection, is established by a set of IFN-stimulated genes (ISGs) encoding antiviral effector proteins. The effector ISGs are transcriptionally regulated by type I IFNs mainly via activation of IFN-stimulated gene factor 3 (ISGF3). In this study, the regulatory elements of effector ISGs were characterized to determine the (epi)genetic features that enable their robust induction by type I IFNs in multiple cell types. We determined the location of regulatory elements, the DNA motifs, the occupancy of ISGF3 subunits (IRF9, STAT1, and STAT2) and other transcription factors, and the chromatin accessibility of 37 effector ISGs in murine dendritic cells. The IFN-stimulated response element (ISRE) and its tripartite version occurred most frequently in the regulatory elements of effector ISGs than in any other tested ISG subsets. Chromatin accessibility at their promoter regions was similar to most other ISGs but higher than at the promoters of inflammation-related cytokines, which were used as a reference gene set. Most effector ISGs (81.1%) had at least one ISGF3 binding region proximal to the transcription start site (TSS), and only a subset of effector ISGs (24.3%) was associated with three or more ISGF3 binding regions. The IRF9 signals were typically higher, and ISRE motifs were "stronger" (more similar to the canonical sequence) in TSS-proximal versus TSS-distal regulatory regions. Moreover, most TSS-proximal regulatory regions were accessible before stimulation in multiple cell types. Our results indicate that "strong" ISRE motifs and universally accessible promoter regions that permit robust, widespread induction are characteristic features of effector ISGs.


Assuntos
Fatores de Restrição Antivirais , Cromatina , Animais , Camundongos , Cromatina/genética , Motivos de Nucleotídeos , Regiões Promotoras Genéticas/genética , Elementos de Resposta/genética , Interferons/metabolismo
3.
Cell Mol Life Sci ; 79(8): 429, 2022 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-35849243

RESUMO

Tight control of gene regulation in dendritic cells (DCs) is important to mount pathogen specific immune responses. Apart from transcription factor binding, dynamic regulation of enhancer activity through global transcriptional repressors like Nuclear Receptor Co-repressor 1 (NCoR1) plays a major role in fine-tuning of DC responses. However, how NCoR1 regulates enhancer activity and gene expression in individual or multiple Toll-like receptor (TLR) activation in DCs is largely unknown. In this study, we did a comprehensive epigenomic analysis of murine conventional type-I DCs (cDC1) across different TLR ligation conditions. We profiled gene expression changes along with H3K27ac active enhancers and NCoR1 binding in the TLR9, TLR3 and combined TLR9 + TLR3 activated cDC1. We observed spatio-temporal activity of TLR9 and TLR3 specific enhancers regulating signal specific target genes. Interestingly, we found that NCoR1 differentially controls the TLR9 and TLR3-specific responses. NCoR1 depletion specifically enhanced TLR9 responses as evident from increased enhancer activity as well as TLR9-specific gene expression, whereas TLR3-mediated antiviral response genes were negatively regulated. We validated that NCoR1 KD cDC1 showed significantly decreased TLR3 specific antiviral responses through decreased IRF3 activation. In addition, decreased IRF3 binding was observed at selected ISGs leading to their decreased expression upon NCoR1 depletion. Consequently, the NCoR1 depleted cDC1 showed reduced Sendai Virus (SeV) clearance and cytotoxic potential of CD8+ T cells upon TLR3 activation. NCoR1 directly controls the majority of these TLR specific enhancer activity and the gene expression. Overall, for the first time, we revealed NCoR1 mediates transcriptional control towards TLR9 as compared to TLR3 in cDC1.


Assuntos
Receptor 3 Toll-Like , Receptor Toll-Like 9 , Animais , Antivirais , Linfócitos T CD8-Positivos , Células Dendríticas/metabolismo , Epigenômica , Fator Regulador 3 de Interferon/genética , Fator Regulador 3 de Interferon/metabolismo , Camundongos , Correpressor 1 de Receptor Nuclear/genética , Correpressor 1 de Receptor Nuclear/metabolismo , Transdução de Sinais , Receptor 3 Toll-Like/genética , Receptor 3 Toll-Like/metabolismo , Receptor Toll-Like 9/genética , Receptor Toll-Like 9/metabolismo , Receptores Toll-Like
4.
Eur J Immunol ; 51(5): 1126-1142, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33527393

RESUMO

Dendritic cell (DC) activation and cytokine production is tightly regulated. In this study, we found that Zbtb10 expression is activation dependent and it is essential for the immunogenic function of cDC1. Zbtb10 knockdown (KD) significantly reduced the expression of co-stimulatory genes CD80 and CD86 along with cytokines including IL-12, IL-6, and IL-10, in activated cDC1 Mutu-DC line. Consequently, the clonal expansion of CD44+ effector T cells in co-cultured CD4+ T cells was drastically reduced owing to significantly reduced IL-2. At the same time, these CD44+ effector T cells were unable to differentiate toward Tbet+ IFNγ+ Th1 subtype. Instead, an increased frequency of Th2 cells expressing GATA3+ and IL-13+ was observed. Interestingly, in Zbtb10 KD condition the co-cultured T cells depicted increased expression of PD1 and LAG3, the T-cell anergic markers. Moreover, the global transcriptome analysis identified that Zbtb10 is pertinent for DC activation and its depletion in cDC1 completely shuts down their immune responses. Mechanistic analysis revealed that Zbtb10 KD enhanced the expression of NKRF (NF-κB repressing factor) leading to drastic suppression of NF-κB related genes. Zbtb10 KD abrogated p65 and RelB nuclear translocation, thereby controlling the activation and maturation of cDC1 and the ensuing adaptive T cell responses.


Assuntos
Citocinas/biossíntese , Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Fatores de Transcrição/metabolismo , Animais , Biomarcadores , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Linhagem Celular , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Ativação Linfocitária/imunologia , Camundongos , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo
5.
Eur J Immunol ; 50(12): 1959-1975, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32644192

RESUMO

Plasmacytoid dendritic cells (DCs) are reported to induce robust type-I interferon (IFN) response, whereas cDC1 DCs develop moderate type-I IFN response upon TLR9 stimulation. It is very interesting to understand how this signaling under TLR9 is tightly regulated for the induction of type-I IFNs. Here, we report co-repressor protein NCoR1 as the major factor fine-tuning the signaling pathways regulating IFN-ß expression under TLR9 in cDC1 DCs. We found that NCoR1 knockdown induced a robust IFN-ß-mediated antiviral response upon TLR9 activation in cDC1 DCs. At the molecular level, we showed that NCoR1 directly repressed MyD88-IRF7 signaling axis in cDC1 cells. Therefore, NCoR1 depletion enhanced pIRF7 levels, IFN-ß secretion, and downstream pSTAT1-pSTAT2 signaling, leading to sustained induction of IFN stimulatory genes. Integrative genomic analysis depicted strong enrichment of an antiviral gene-module in CpG-activated NCoR1 knockdown DCs upon TLR9 activation. Moreover, we confirmed our findings in primary DCs derived from splenocytes of WT and NCoR1 DC-/- animals, which showed protection from Sendai and Vesicular Stomatitis viruses upon CpG activation. Ultimately, we identified that NCoR1-HDAC3 complex is involved in repressing the type-I IFN response in cDC1 DCs.


Assuntos
Células Dendríticas/metabolismo , Fator Regulador 7 de Interferon/metabolismo , Interferon Tipo I/metabolismo , Fator 88 de Diferenciação Mieloide/metabolismo , Correpressor 1 de Receptor Nuclear/metabolismo , Receptor Toll-Like 9/metabolismo , Animais , Células Cultivadas , Feminino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transdução de Sinais/fisiologia
6.
Soft Matter ; 17(15): 4122-4132, 2021 Apr 21.
Artigo em Inglês | MEDLINE | ID: mdl-33734259

RESUMO

Recently, the utilization of inferior grade coal for the production of fuel-based materials, i.e., metallurgical coke, is an exciting research area in the industrial sector because of the limited reserves of prime coking coal worldwide. In the steel industry, coal tar is the most abundant and sustainable cost-effective by-product, which is a source of an adequate amount of aromatic components such as phenol or its derivative with polycyclic aromatic hydrocarbons. Therefore, for the first time, we developed a novel organic polymeric additive through a cross-linking polymerization technique using a coal-tar precursor and paraformaldehyde monomer with a glycol-tetraline-based plasticizing agent and explored its application for use as inferior coal in metallurgical coke production. Our synthesized polymer was a homogeneous flowable liquid material; the synthesis process was simple, easily scalable with a high production yield (∼90%), and economical. The interaction of the polymeric additive with the coal matrix was investigated via TGA and H2 evolution study to understand the role of the polymer in coal carbonization. The polymeric additive has significantly improved the crucible swelling number (CSN), fluidity, and plastic layer thickness property of coal. In this connection, we also performed a computational study to rationalize the mechanism of action of the polymeric additive. Exploration of the reaction features through density functional theory calculations offered significant insight into the role of the polymer in assisting coal fluidity development. Addition of the polymer prominently enhanced the coke strength after reaction (CSR) of a non-coking coal enriched blend during carbonization. This study discloses new prospects in the steel industry for the sustainable and bulk scale synthesis of a coal tar-based polymeric additive for the profitable production of metallurgical coke.

7.
J Phys Chem A ; 122(42): 8377-8389, 2018 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-30284830

RESUMO

A gas-phase mechanistic investigation of the unimolecular, water/ammonia-assisted decomposition reactions of the α-hydroxy hydroperoxides (HPs) and hydroperoxide arylamines (a-HPs) produced during the styrene ozonolysis has been carried out theoretically in the present article. The instrumental role of stereochemistry in controlling the outcome of individual reactions has been discussed. Thermodynamic parameters (Δ G298K, Δ H298K, Δ E0K) associated with individual reactions have also been computed. The rate constants estimated for individual reactions using conventional transition state theory (TST) combined with statistical mechanics provide a comprehensive understanding of the reaction mechanism and also elucidate the atmospheric fate of Criegee intermediates. Considering the feasibility of reactions from thermodynamic and kinetic points of view, while aldehyde (PhCHO) formation pathway originating from bimolecular decomposition of HP is found to be kinetically favored, benzoic acid formation pathway remains favored thermodynamically. A similar consideration for the bimolecular reactions of a-HP reveals the phenylmethanimine formation pathway to be kinetically favored, while the benzamide formation pathway is favored thermodynamically. Our findings appear to be in excellent agreement with the experimental observations.

8.
Phys Chem Chem Phys ; 17(31): 20231-49, 2015 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-26186058

RESUMO

The adsorption of a model nerve agent, O,S-dimethyl methylphosphonothiolate (DMPT), on the hydroxylated and unhydroxylated nano-crystalline magnesium oxide surface followed by the nucleophilic attack of ammonia (NH3) is investigated at the M06-2X/6-311++G(d,p) level of theory using the representative cluster models. The geometries of DMPT and NH3 are fully optimized, while the geometry of the oxide fragment is kept frozen. The main insight of this study is the incorporation of the Eley-Rideal mechanism for the first time in the detoxification process, where one of the reactant molecules (DMPT) is adsorbed and the other one (NH3) reacts with it directly impinging from the gas phase. There are two possible pathways of nucleophilic detoxification, either concerted or stepwise. The nature of the first transition state of nucleophilic attack in both pathways is the vital step for degradation. Our calculated results predict that the reaction of DMPT with NH3 gives rise to both P-S and P-O bond cleavage completely. Also, the P-S cleavage is found to be the favorable one over P-O bond breaking. The exploration of the overall reaction mechanism has established the catalytic activity of nano-crystalline MgO in nucleophilic DMPT degradation, as in all cases the activation barriers have reduced compared to the previously reported aminolysis of DMPT in the gas phase. Interestingly, the hydroxylated model has better catalytic performance than the unhydroxylated one.

9.
J Phys Chem A ; 119(20): 4939-52, 2015 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-25915481

RESUMO

A detailed mechanistic investigation of Si-Me formation over the silicon (100)-2 × 1 surface using the Si9H12 cluster model has been performed using various reagents, based on two basic mechanisms: dissociation and substitution. The reagents CH4, CH3Cl for dissociation and CH3Li, CH3MgBr for substitution mechanism are used to explore the methylation process on the silicon surface at the M062X/6-311+G(2d, p) level of theory. The associated potential energy surfaces explored here are aimed to unveil the most favored pathway of methylation with appropriate reagents. Dissociation of methane forms a monomethylated product (D1) through an energetically unfavorable pathway. All the adsorption modes of CH3Cl over the silicon surface are also detected and analyzed. Methyl chloride dissociates to form another monomethylated product D2 and its derivative D3 in the entrance channel, while, in the next step, bridged compounds I1 (Cl-bridged) and I2 (H-bridged) are produced from them, respectively. The C-Cl dissociation leads to the formation of D2 having a lower activation barrier. With a comparably high activation barrier in the C-H dissociation, producing D3, very interestingly carbene intermediate has been detected in the reaction pathway. Detection of energetically unfavored conversions from D2 to I1 and D3 to I2 ensured that the methylation process will not be hampered through these interconversions. For substitution, HCl- and Cl2-passivated Si surfaces are taken, where chlorine is to be substituted by the methyl group of both of the methylating agents. With both substituents, HCl-passivated Si9H12 gives D1. The substitution process on Cl2-passivated Si9H12 leads to the formation of D2 in the first step and dimethylated product (S1) in the final step. In all the above substitution processes, methyl lithium proved to be the better substituent for the formations of D1, D2, and S1 on HCl- or Cl2-passivated surfaces. The present work not only demonstrated methyl lithium as one of the best methylating agents but also revealed the interrelation among the dissociative adsorption modes of CH3Cl, reported earlier, in a single potential energy surface with a remarkable detection of carbene intermediate formed in the pathway of C-H dissociation.

10.
Phytomedicine ; 123: 155181, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38091824

RESUMO

BACKGROUND: Triple negative breast cancer (TNBC) is the most aggressive subtype of breast cancer and exhibits high rate of chemoresistance, metastasis, and relapse. This can be attributed to the failure of conventional therapeutics to target a sub-population of slow cycling or quiescent cells called as cancer stem cells (CSCs). Therefore, elimination of CSCs is essential for effective TNBC treatment. PURPOSE: Research suggests that breast CSCs exhibit elevated glycolytic metabolism which directly contributes in maintenance of stemness, self-renewability and chemoresistance as well as in tumor progression. Therefore, this study aimed to target rewired metabolism which can serve as Achilles heel for CSCs population and have far reaching effect in TNBC treatment. METHODS: We used two preclinical models, zebrafish and nude mice to evaluate the fate of nanoparticles as well as the therapeutic efficacy of both piperlongumine (PL) and its nanomedicine (PL-NPs). RESULTS: In this context, we explored a phytochemical piperlongumine (PL) which has potent anti-cancer properties but poor pharmacokinetics impedes its clinical translation. So, we developed PLGA based nanomedicine for PL (PL-NPs), and demonstrated that it overcomes the pharmacokinetic limitations of PL, along with imparting advantages of selective tumor targeting through Enhanced Permeability and Retention (EPR) effect in zebrafish xenograft model. Further, we demonstrated that PL-NPs efficiently inhibit glycolysis in CSCs through inhibition of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by modulating glutathione S-transferase pi 1 (GSTP1) and upregulation of fructose-1,6-bisphosphatase 1 (FBP1), a rate-limiting enzyme in gluconeogenesis. We also illustrated that inhibition of glycolysis results in overall tumor regression in two preclinical models. CONCLUSION: This study discusses novel mechanism of action by which PL acts on CSCSs. Taken together our study provides insight into development of PL based nanomedicine which could be exploited in clinics to achieve complete eradication of TNBC by targeting CSCs.


Assuntos
Benzodioxóis , Neoplasias de Mama Triplo Negativas , Animais , Camundongos , Humanos , Neoplasias de Mama Triplo Negativas/metabolismo , Peixe-Zebra/metabolismo , Nanomedicina , Camundongos Nus , Linhagem Celular Tumoral , Recidiva Local de Neoplasia/metabolismo , Células-Tronco Neoplásicas , Gliceraldeído-3-Fosfato Desidrogenases/metabolismo , Gliceraldeído-3-Fosfato Desidrogenases/farmacologia , Gliceraldeído-3-Fosfato Desidrogenases/uso terapêutico , Glicólise
11.
ACS Appl Bio Mater ; 7(1): 443-451, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38064365

RESUMO

Although photodynamic therapy is a promising approach for cancer treatment, it has limited clinical application due to the poor performance of conventional photosensitizers. In this study, we present a carbon nanoparticle-based photosensitizer for efficient photodynamic cell therapy. The nanoparticles have been synthesized from a steel industry-based waste material, exhibiting strong fluorescence in the visible region, rapidly entering the cell via non-endocytic uptake, and localizing within the mitochondria. Light exposure of nanoparticle-labeled cells offers efficient photodynamic therapy and induces cytotoxicity. Overall, this study highlights the utility of carbon nanoparticles in efficient photodynamic therapy via rapid cellular uptake and subcellular targeting.


Assuntos
Nanopartículas , Fotoquimioterapia , Fármacos Fotossensibilizantes/farmacologia , Fármacos Fotossensibilizantes/uso terapêutico , Nanopartículas/uso terapêutico , Fluorescência
12.
Autophagy ; 20(3): 697-698, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37953605

RESUMO

Mycobacterium tuberculosis (Mtb) employs a multifaceted arsenal to elude host defense mechanisms, including those associated with autophagy and lysosome function. Within the realm of host-pathogen interactions, NCOR1, a well-recognized transcriptional co-repressor, is known to associate with a multitude of protein complexes to effect the repression of a diverse spectrum of genes. However, its role in regulating macroautophagy/autophagy, lysosome biogenesis, and, by extension, Mtb pathogenesis remains unexplored. The depletion of NCOR1 assumes a pivotal role in the control of the AMPK-MTOR-TFEB signaling axis, thereby fine-tuning cellular ATP homeostasis. This finely orchestrated adjustment further alters the profile of proteins involved in autophagy and lysosomal biogenesis through its master regulator, TFEB, culminating in the increased Mtb survival within the host milieu. Furthermore, the treatment of NCOR1-depleted cells with either rapamycin, antimycin A, or metformin demonstrates a capacity to restore the TFEB activity and LC3-II levels, consequently restoring the capacity of host cells to clear Mtb. Additionally, exogenous NCOR1 expression rescues the AMPK-MTOR-TFEB signaling axis and essentially the autophagic induction machinery. Overall, these findings demonstrate a crucial role of NCOR1 in regulating Mtb pathogenesis within myeloid cells and sheds light toward its involvement in the development of novel host-directed therapies.


Assuntos
Mycobacterium tuberculosis , Mycobacterium tuberculosis/metabolismo , Autofagia/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Fatores de Transcrição de Zíper de Leucina e Hélice-Alça-Hélix Básicos/metabolismo , Fatores de Transcrição/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Lisossomos/metabolismo
13.
J Comput Chem ; 34(22): 1907-16, 2013 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-23712937

RESUMO

The binding properties of a series of benzenesulfonamide inhibitors (4-substituted-ureido-benzenesulfonamides, UBSAs) of human carbonic anhydrase II (hCA II) enzyme with active site residues have been studied using a hybrid quantum mechanical/molecular mechanical (QM/MM) model. To account for the important docking interactions between the UBSAs ligand and hCA II enzyme, a molecular docking program AutoDock Vina is used. The molecular docking results obtained by AutoDock Vina revealed that the docked conformer has root mean square deviation value less than 1.50 Å compared to X-ray crystal structures. The inhibitory activity of UBSA ligands against hCA II is found to be in good agreement with the experimental results. The thermodynamic parameters for inhibitor binding show that hydrogen bonding, hydrophilic, and hydrophobic interactions play a major role in explaining the diverse inhibitory range of these derivatives. Additionally, natural bond orbital analysis is performed to characterize the ligand-metal charge transfer stability. The insights gained from this study have great potential to design new hCA-II inhibitor, 4-[3-(1-p-Tolyl-4-trifluoromethyl-1H-pyrazol-3-yl)-ureido]-benzenesulfonamide, which belongs to the family of UBSA inhibitors and shows similar type of inhibitor potency with hCA II. This work also reveals that a QM/MM model and molecular docking method are computationally feasible and accurate for studying substrate-protein inhibition.


Assuntos
Anidrase Carbônica II/antagonistas & inibidores , Inibidores da Anidrase Carbônica/farmacologia , Teoria Quântica , Sulfonamidas/farmacologia , Anidrase Carbônica II/metabolismo , Inibidores da Anidrase Carbônica/química , Cristalografia por Raios X , Humanos , Ligantes , Modelos Moleculares , Estrutura Molecular , Relação Estrutura-Atividade , Sulfonamidas/química , Termodinâmica , Benzenossulfonamidas
14.
J Phys Chem A ; 117(16): 3496-506, 2013 Apr 25.
Artigo em Inglês | MEDLINE | ID: mdl-23540856

RESUMO

trans-2-Chlorovinyldichloroarsine (lewisite, L agent, Lew-I) acts as a blistering agents. British anti-lewisite (BAL, 2,3-dimercaptopropanol) has long been used as an L-agent antidote. The main reaction channels for the detoxification proceed via breaking of As-Cl bonds and formation of As-S bonds, producing stable, nontoxic ring product [(2-methyl-1,3,2-dithiarsolan-4-yl)methanol]. M06-2X/GENECP calculations have been carried out to establish the enhanced rate of detoxification mechanism in the presence of NH3 and H2O catalysts in both gas and solvent phases, which has been modeled by use of the polarized continuum model (PCM). In addition, natural bond orbital (NBO) and atoms in molecules (AIM) analysis have been performed to characterize the intermolecular hydrogen bonding in the transition states. Transition-state theory (TST) calculation establishes that the rates of NH3-catalyzed (2.88 × 10(-11) s(-1)) and H2O-catalyzed (2.42 × 10(-11) s(-1)) reactions are reasonably faster than the uncatalyzed detoxification (5.44 × 10(-13) s(-1)). The results obtained by these techniques give new insight into the mechanism of the detoxification process, identification and thermodynamic characterization of the relevant stationary species, the proposal of alternative paths on modeled potential energy surfaces for uncatalyzed reaction, and the rationalization of the mechanistic role played by catalysts and solvents.


Assuntos
Amônia/química , Antídotos/química , Arsenicais/química , Quelantes/química , Substâncias para a Guerra Química/química , Água/química , Catálise , Dimercaprol/química , Ligação de Hidrogênio , Cinética , Modelos Químicos , Teoria Quântica , Soluções , Termodinâmica
15.
J Chem Phys ; 138(16): 164319, 2013 Apr 28.
Artigo em Inglês | MEDLINE | ID: mdl-23635150

RESUMO

The performance of double hybrid density functionals (DHDFs) has been assessed by studying the spectroscopic properties and potential energy curves of OCS-C2H4 (carbonyl sulfide-ethylene) and OCS-C4H6 (carbonyl sulfide-dimethylacetylene) van der Waals complexes. Both dispersion corrected and uncorrected DHDF theories have been applied to study the intermolecular interaction energies, stability, spectroscopic parameters, rigidity, and binding energies or depths of the potential well of the weakly bound complexes and also to explore the possibility of formation of three isomers of each complex. The correlation consistent valence triple zeta quality basis set is used to investigate the complexes. The calculated results provide insight into the computational methods applied to the weakly bound complexes. The double hybrid density functional B2PLYP and mPW2PLYP methods with dispersion corrections (B2PLYP-D2, B2PLYP-D3 and mPW2PLYP-D2, mPW2PLYP-D3) performed better over the B2PLYP and mPW2PLYP density functional methods without dispersion correction to deal with the weak dispersion interaction that prevails in these complexes. The results obtained by the dispersion-corrected density functional mPW2PLYP-D2 and mPW2PLYP-D3 methods agree very well with the earlier experimental values wherever available. The contributing components of the interaction energy have been analyzed by the symmetry-adapted perturbation theory (SAPT, here, SAPT0) to get insight into the interaction energy.


Assuntos
Hidrocarbonetos/química , Teoria Quântica , Óxidos de Enxofre/química , Interações Hidrofóbicas e Hidrofílicas
16.
J Chem Phys ; 139(23): 234303, 2013 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-24359363

RESUMO

The structures, energies, isomerization, and decomposition pathways of small ionic silicon oxide clusters, SiO(n)(+) (n = 3, 4), on doublet and quartet energy surfaces are investigated by density functional theory. New structural isomers of these ionic clusters have been obtained with this systematic study. The energy ordering of the isomeric cluster ions on doublet spin surface is found to follow the same general trend as that of the neutral ones, while it differs on the quartet surface. Our computational results reveal the energetically most preferred decomposition pathways of the ionic clusters on both spin surfaces. To comprehend the reaction mechanism, bonding evolution theory has also been employed using atoms in molecules formalism. The possible reasons behind the structural deformation of some isomers on quartet surface have also been addressed. Our results are expected to provide important insight into the decomposition mechanism and relative stability of the SiO(n)(+) clusters on both the energy surfaces.

17.
ACS Nano ; 17(6): 6121-6130, 2023 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-36877629

RESUMO

Fabrication of metal-organic framework (MOF) thin films rigidly anchored on suitable substrates is a crucial prerequisite for the integration of these porous hybrid materials into electronic and optical devices. Thus, far, the structural variety for MOF thin films available through layer-by-layer deposition was limited, as the preparation of those surface-anchored metal-organic frameworks (SURMOFs) has several requirements: mild conditions, low temperatures, day-long reaction times, and nonaggressive solvents. We herein present a fast method for the preparation of the MIL SURMOF on Au-surfaces under rather harsh conditions: Using a dynamic layer-by-layer synthesis for MIL-68(In), thin films of adjustable thickness between 50 and 2000 nm could be deposited within only 60 min. The MIL-68(In) thin film growth was monitored in situ using a quartz crystal microbalance. In-plane X-ray diffraction revealed oriented MIL-68(In) growth with the pore-channels of this interesting MOF aligned parallel to the support. Scanning electron microscopy data demonstrated an extraordinarily low roughness of the MIL-68(In) thin films. Mechanical properties and lateral homogeneity of the layer were probed through nanoindentation. These thin films showed extremely high optical quality. By applying a poly(methyl methacrylate) layer and further depositing an Au-mirror to the top, a MOF optical cavity was fabricated that can be used as a Fabry-Perot interferometer. The MIL-68(In)-based cavity showed a series of sharp resonances in the ultraviolet-visible regime. Changes in the refractive index of MIL-68(In) caused by exposure to volatile compounds led to pronounced position shifts of the resonances. Thus, these cavities are well suited to be used as optical read-out sensors.

18.
Redox Biol ; 59: 102575, 2023 02.
Artigo em Inglês | MEDLINE | ID: mdl-36565644

RESUMO

Dendritic cells (DCs) undergo rapid metabolic reprogramming to generate signal-specific immune responses. The fine control of cellular metabolism underlying DC immune tolerance remains elusive. We have recently reported that NCoR1 ablation generates immune-tolerant DCs through enhanced IL-10, IL-27 and SOCS3 expression. In this study, we did comprehensive metabolic profiling of these tolerogenic DCs and identified that they meet their energy requirements through enhanced glycolysis and oxidative phosphorylation (OXPHOS), supported by fatty acid oxidation-driven oxygen consumption. In addition, the reduced pyruvate and glutamine oxidation with a broken TCA cycle maintains the tolerogenic state of the cells. Mechanistically, the AKT-mTOR-HIF-1α-axis mediated glycolysis and CPT1a-driven ß-oxidation were enhanced in these tolerogenic DCs. To confirm these observations, we used synthetic metabolic inhibitors and found that the combined inhibition of HIF-1α and CPT1a using KC7F2 and etomoxir, respectively, compromised the overall transcriptional signature of immunological tolerance including the regulatory cytokines IL-10 and IL-27. Functionally, treatment of tolerogenic DCs with dual KC7F2 and etomoxir treatment perturbed the polarization of co-cultured naïve CD4+ T helper (Th) cells towards Th1 than Tregs, ex vivo and in vivo. Physiologically, the Mycobacterium tuberculosis (Mtb) infection model depicted significantly reduced bacterial burden in BMcDC1 ex vivo and in CD103+ lung DCs in Mtb infected NCoR1DC-/-mice. The spleen of these infected animals also showed increased Th1-mediated responses in the inhibitor-treated group. These findings suggested strong involvement of NCoR1 in immune tolerance. Our validation in primary human monocyte-derived DCs (moDCs) showed diminished NCOR1 expression in dexamethasone-derived tolerogenic moDCs along with suppression of CD4+T cell proliferation and Th1 polarization. Furthermore, the combined KC7F2 and etomoxir treatment rescued the decreased T cell proliferative capacity and the Th1 phenotype. Overall, for the first time, we demonstrated here that NCoR1 mediated control of glycolysis and fatty acid oxidation fine-tunes immune tolerance versus inflammation balance in murine and human DCs.


Assuntos
Interleucina-10 , Interleucina-27 , Humanos , Camundongos , Animais , Interleucina-10/metabolismo , Interleucina-27/metabolismo , Células Dendríticas/metabolismo , Tolerância Imunológica , Glicólise , Ácidos Graxos/metabolismo , Diferenciação Celular , Células Cultivadas , Correpressor 1 de Receptor Nuclear/metabolismo
19.
Indian J Endocrinol Metab ; 27(5): 398-403, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38107729

RESUMO

Introduction: A structured dedicated health programme for Type 1 diabetes mellitus (T1DM) has been initiated in the state of West Bengal, India. Aim: The aim is to provide comprehensive healthcare to all children, adolescents and young adults living with T1DM, along with the provision of free supply of insulin, glucose measuring devices, blood glucose test strips, and other logistics. The strategic framework for programme implementation is to utilise the infrastructure and manpower of the already existing non-communicable disease (NCD) clinic under National Health Mission. Methodology: Establishing dedicated T1DM clinics in each district hospital by utilising existing healthcare delivery systems, intensive training and hand-holding of named human resources; providing comprehensive healthcare service and structured diabetes education to all T1DM patients; and building an electronic registry of patients are important components of the programme. T1DM clinics run once a week on the same day throughout the state. All T1DM patients are treated with the correct dose of insulin, both human regular insulin and glargine insulin. Patients are routinely monitored monthly to ensure good glycaemic control and prevent complications of the disease. Routine anthropometric examination and required laboratory investigations are conducted in the set-up of the already existing NCD clinic. Ongoing monitoring and evaluation of the T1DM programme are being conducted in terms of glycated haemoglobin (HbA1c) values, growth and development, complication rates, psychological well-being, quality of life, and direct and indirect expenditure incurred by families. Through this programme, any bottlenecks or gaps in service delivery will be identified and corrective measures will be adopted to ensure better health outcomes for those living with T1DM.

20.
J Phys Chem A ; 116(32): 8382-96, 2012 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-22830557

RESUMO

The mechanism for the aminolysis of a model nerve agent, O,S-dimethyl methylphosphonothiolate, is investigated both at density functional level using M062X method with 6-311++G(d,p) basis set and at ab initio level using the second-order Møller-Plesset perturbation theory (MP2) with the 6-311+G(d,p) basis set. The catalytic role of an additional NH(3) and H(2)O molecule is also examined. The solvent effects of acetonitrile, ethanol, and water are taken into account employing the conductor-like screening model (COSMO) at the single-point M062X/6-311++G(d,p) level of theory. Two possible dissociation pathways, methanethiol and methyl alcohol dissociations, along with two different neutral mechanisms, a concerted one and a stepwise route through two neutral intermediates, for each pathway are investigated. Hyperconjugation stabilization that has an effect on the stability of generated transition states are investigated by natural bond order (NBO) approach. Additionally, quantum theory of atoms in molecules analysis is performed to evaluate the bond critical (BCP) properties and to quantify strength of different types of interactions. The calculated results predict that the reaction of O,S-dimethyl methylphosphonothiolate with NH(3) gives rise to parallel P-S and P-O bond cleavages, and in each cleavage the neutral stepwise route is always favorable than the concerted one. The mechanism of NH(3) and H(2)O as catalyst is nearly similar, and they facilitate the shuttle of proton to accelerate the reaction. The steps involving the H(2)O-mediated proton transfer are the most suitable ones. The first steps for the stepwise process, the formation of neutral intermediate, are the rate-determining step. It is observed that in the presence of catalyst the reaction in the stepwise path possesses almost half the activation energy of the uncatalyzed one. A bond-order analysis using Wiberg bond indexes obtained by NBO calculation predicts that usually all individual steps of the reactions occur in a concerted fashion showing equal progress along different reaction coordinates.


Assuntos
Substâncias para a Guerra Química/química , Compostos Organotiofosforados/química , Prótons , Acetonitrilas , Amônia , Catálise , Simulação por Computador , Etanol , Hidrólise , Cinética , Modelos Químicos , Mimetismo Molecular , Teoria Quântica , Solventes , Termodinâmica , Água
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