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1.
Part Fibre Toxicol ; 21(1): 9, 2024 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-38419076

RESUMO

BACKGROUND: Zinc oxide nanoparticles (ZnONPs) are common materials used in skin-related cosmetics and sunscreen products due to their whitening and strong UV light absorption properties. Although the protective effects of ZnONPs against UV light in intact skin have been well demonstrated, the effects of using ZnONPs on damaged or sunburned skin are still unclear. In this study, we aimed to reveal the detailed underlying mechanisms related to keratinocytes and macrophages exposed to UVB and ZnONPs. RESULTS: We demonstrated that ZnONPs exacerbated mouse skin damage after UVB exposure, followed by increased transepidermal water loss (TEWL) levels, cell death and epithelial thickness. In addition, ZnONPs could penetrate through the damaged epithelium, gain access to the dermis cells, and lead to severe inflammation by activation of M1 macrophage. Mechanistic studies indicated that co-exposure of keratinocytes to UVB and ZnONPs lysosomal impairment and autophagy dysfunction, which increased cell exosome release. However, these exosomes could be taken up by macrophages, which accelerated M1 macrophage polarization. Furthermore, ZnONPs also induced a lasting inflammatory response in M1 macrophages and affected epithelial cell repair by regulating the autophagy-mediated NLRP3 inflammasome and macrophage exosome secretion. CONCLUSIONS: Our findings propose a new concept for ZnONP-induced skin toxicity mechanisms and the safety issue of ZnONPs application on vulnerable skin. The process involved an interplay of lysosomal impairment, autophagy-mediated NLRP3 inflammasome and macrophage exosome secretion. The current finding is valuable for evaluating the effects of ZnONPs for cosmetics applications.


Assuntos
Exossomos , Nanopartículas , Óxido de Zinco , Camundongos , Animais , Óxido de Zinco/toxicidade , Proteína 3 que Contém Domínio de Pirina da Família NLR , Raios Ultravioleta/efeitos adversos , Citocinas , Inflamassomos , Nanopartículas/toxicidade , Células Epiteliais
2.
Biomed Pharmacother ; 166: 115429, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37673018

RESUMO

Neuroblastoma, a childhood cancer affecting the sympathetic nervous system, continues to challenge the development of potent treatments due to the limited availability of druggable targets for this aggressive illness. Recent investigations have uncovered that phosphoglycerate dehydrogenase (PHGDH), an essential enzyme for de novo serine synthesis, serves as a non-oncogene dependency in high-risk neuroblastoma. In this study, we show that homoharringtonine (HHT) acts as a PHGDH inhibitor, inducing intricate alterations in cellular metabolism, and thus providing an efficient treatment for neuroblastoma. We have experimentally verified the reliance of neuroblastoma on PHGDH and employed molecular docking, thermodynamic evaluations, and X-ray crystallography techniques to determine the bond interactions between HHT and PHGDH. Administering HHT to treat neuroblastoma resulted in effective cell elimination in vitro and tumor reduction in vivo. Metabolite and functional assessments additionally disclosed that HHT treatment suppressed de novo serine synthesis, initiating intricate metabolic reconfiguration and oxidative stress in neuroblastoma. Collectively, these discoveries highlight the potential of targeting PHGDH using HHT as a potent approach for managing high-risk neuroblastoma.


Assuntos
Neuroblastoma , Fosfoglicerato Desidrogenase , Humanos , Criança , Mepesuccinato de Omacetaxina , Simulação de Acoplamento Molecular , Inibidores Enzimáticos , Neuroblastoma/tratamento farmacológico , Serina
3.
Parkinsonism Relat Disord ; 111: 105431, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37164870

RESUMO

Magnetic resonance-guided focused ultrasound (MRgFUS) is a new surgical treatment for Parkinson's disease (PD). Previous experience with radiofrequency lesionectomy and deep brain stimulation (DBS) has identified several candidate targets for MRgFUS intended to alleviate the motor symptoms of PD. The main advantage of MRgFUS is that it is incisionless. MRgFUS has certain limitations and is associated with adverse effects. The present study reviews the literature on conventional surgical interventions for PD, discusses recent studies on MRgFUS, and the comparison between DBS and MRgFUS for PD. The reviews aims to provide an essential reference for neurologists to select the appropriate treatments for patients with PD.


Assuntos
Estimulação Encefálica Profunda , Tremor Essencial , Doença de Parkinson , Procedimentos Cirúrgicos Ultrassônicos , Humanos , Doença de Parkinson/diagnóstico por imagem , Doença de Parkinson/cirurgia , Resultado do Tratamento , Tremor Essencial/terapia , Imageamento por Ressonância Magnética , Espectroscopia de Ressonância Magnética
4.
Nat Prod Rep ; 40(9): 1521-1549, 2023 09 20.
Artigo em Inglês | MEDLINE | ID: mdl-36891755

RESUMO

Covering: from 2000 up to the very early part of 2023S-Adenosyl-L-methionine (SAM) is a naturally occurring trialkyl sulfonium molecule that is typically associated with biological methyltransfer reactions. However, SAM is also known to donate methylene, aminocarboxypropyl, adenosyl and amino moieties during natural product biosynthetic reactions. The reaction scope is further expanded as SAM itself can be modified prior to the group transfer such that a SAM-derived carboxymethyl or aminopropyl moiety can also be transferred. Moreover, the sulfonium cation in SAM has itself been found to be critical for several other enzymatic transformations. Thus, while many SAM-dependent enzymes are characterized by a methyltransferase fold, not all of them are necessarily methyltransferases. Furthermore, other SAM-dependent enzymes do not possess such a structural feature suggesting diversification along different evolutionary lineages. Despite the biological versatility of SAM, it nevertheless parallels the chemistry of sulfonium compounds used in organic synthesis. The question thus becomes how enzymes catalyze distinct transformations via subtle differences in their active sites. This review summarizes recent advances in the discovery of novel SAM utilizing enzymes that rely on Lewis acid/base chemistry as opposed to radical mechanisms of catalysis. The examples are categorized based on the presence of a methyltransferase fold and the role played by SAM within the context of known sulfonium chemistry.


Assuntos
Metiltransferases , S-Adenosilmetionina , Metiltransferases/química , Catálise
5.
J Am Chem Soc ; 145(6): 3656-3664, 2023 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-36719327

RESUMO

OxsB is a B12-dependent radical SAM enzyme that catalyzes the oxidative ring contraction of 2'-deoxyadenosine 5'-phosphate to the dehydrogenated, oxetane containing precursor of oxetanocin A phosphate. AlsB is a homologue of OxsB that participates in a similar reaction during the biosynthesis of albucidin. Herein, OxsB and AlsB are shown to also catalyze radical mediated, stereoselective C2'-methylation of 2'-deoxyadenosine monophosphate. This reaction proceeds with inversion of configuration such that the resulting product also possesses a C2' hydrogen atom available for abstraction. However, in contrast to methylation, subsequent rounds of catalysis result in C-C dehydrogenation of the newly added methyl group to yield a 2'-methylidene followed by radical addition of a 5'-deoxyadenosyl moiety to produce a heterodimer. These observations expand the scope of reactions catalyzed by B12-dependent radical SAM enzymes and emphasize the susceptibility of radical intermediates to bifurcation along different reaction pathways even within the highly organized active site of an enzyme.


Assuntos
Metiltransferases , S-Adenosilmetionina , S-Adenosilmetionina/metabolismo , Domínio Catalítico , Metilação , Metiltransferases/metabolismo , Catálise , Radicais Livres/química
6.
Angew Chem Int Ed Engl ; 61(42): e202210362, 2022 10 17.
Artigo em Inglês | MEDLINE | ID: mdl-36064953

RESUMO

Oxetanocin A and albucidin are two oxetane natural products. While the biosynthesis of oxetanocin A has been described, less is known about albucidin. In this work, the albucidin biosynthetic gene cluster is identified in Streptomyces. Heterologous expression in a nonproducing strain demonstrates that the genes alsA and alsB are necessary and sufficient for albucidin biosynthesis confirming a previous study (Myronovskyi et al. Microorganisms 2020, 8, 237). A two-step construction of albucidin 4'-phosphate from 2'-deoxyadenosine monophosphate (2'-dAMP) is shown to be catalyzed in vitro by the cobalamin dependent radical S-adenosyl-l-methionine (SAM) enzyme AlsB, which catalyzes a ring contraction, and the radical SAM enzyme AlsA, which catalyzes elimination of a one-carbon fragment. Isotope labelling studies show that AlsB catalysis begins with stereospecific H-atom transfer of the C2'-pro-R hydrogen from 2'-dAMP to 5'-deoxyadenosine, and that the eliminated one-carbon fragment originates from C3' of 2'-dAMP.


Assuntos
Produtos Biológicos , S-Adenosilmetionina , Antivirais , Carbono , Éteres Cíclicos , Hidrogênio , Nucleosídeos , Fosfatos , S-Adenosilmetionina/metabolismo , Vitamina B 12/metabolismo
7.
Mol Med ; 28(1): 93, 2022 08 08.
Artigo em Inglês | MEDLINE | ID: mdl-35941532

RESUMO

BACKGROUND: Diffuse large B cell lymphoma (DLBCL) is an aggressive and molecularly heterogeneous non-Hodgkin's lymphoma. The B cell receptor (BCR) signaling pathway in DLBCL emerges as a new drug target. Protein phosphatase SHP-1 negatively regulates several oncogenic tyrosine kinases and plays a tumor suppressive role. METHODS: The direct SHP-1 agonists were used to evaluate the potential therapeutic implication of SHP-1 in DLBCL. Immunohistochemical staining for SHP-1 was quantified by H-score. The SHP-1 phosphatase activity was determined using tyrosine phosphatase assay. In vitro studies, including MTT, western blot analysis and cell apoptosis, were utilized to examined biological functions of SHP-1. RESULTS: Oral administration of SHP-1 agonist showed the potent anti-tumor effects compared to a selective Bruton's tyrosine kinase (BTK) inhibitor ibrutinib in mice bearing U2932 xenografts. SHP-1 agonist increased SHP-1 activity as well as downregulated p-Lyn in vivo. Here, we demonstrated that immunohistochemical staining for SHP-1 expression was positive in 76% of DLBCL samples. SHP-1 agonist exerted anti-proliferative and apoptotic effects compared with ibrutinib in DLBCL cells. Mechanistically, SHP-1 agonist decreased BCR signaling, especially p-Lyn, and led to apoptosis. CONCLUSIONS: These data suggest that SHP-1 negatively regulates phosphorylation of Lyn, and targeting SHP-1/p-Lyn using SHP-1 agonist has therapeutic potential for treatment of DLBCL.


Assuntos
Linfoma Difuso de Grandes Células B , Animais , Linhagem Celular Tumoral , Humanos , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/metabolismo , Linfoma Difuso de Grandes Células B/patologia , Camundongos , Proteína Tirosina Fosfatase não Receptora Tipo 6 , Receptores de Antígenos de Linfócitos B/metabolismo , Transdução de Sinais , Tirosina/farmacologia , Tirosina/uso terapêutico , Quinases da Família src/metabolismo
8.
J Am Chem Soc ; 144(24): 10968-10977, 2022 06 22.
Artigo em Inglês | MEDLINE | ID: mdl-35687050

RESUMO

Oxazinomycin is a C-nucleoside natural product with antibacterial and antitumor activities. In addition to the characteristic C-glycosidic linkage shared with other C-nucleosides, oxazinomycin also features a structurally unusual 1,3-oxazine moiety, the biosynthesis of which had previously been unknown. Herein, complete in vitro reconstitution of the oxazinomycin biosynthetic pathway is described. Construction of the C-glycosidic bond between ribose 5-phosphate and an oxygen-labile pyridine heterocycle is catalyzed by the C-glycosidase OzmB and involves formation of an enzyme-substrate Schiff base intermediate. The DUF4243 family protein OzmD is shown to catalyze oxygen insertion and rearrangement of the pyridine C-nucleoside intermediate to generate the 1,3-oxazine moiety along with the elimination of cyanide. Spectroscopic analysis and mutagenesis studies indicate that OzmD is a novel nonheme iron-dependent enzyme in which the catalytic iron center is likely coordinated by four histidine residues. These results provide the first example of 1,3-oxazine biosynthesis catalyzed by an unprecedented iron-dependent mono-oxygenase.


Assuntos
Ferro , Oxigenases , Vias Biossintéticas , Ferro/química , Nucleosídeos/metabolismo , Oxazinas , Oxigênio/química , Oxigenases/metabolismo , Piridinas , Uridina/análogos & derivados
9.
Methods Enzymol ; 669: 71-90, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35644181

RESUMO

The B12-dependent radical SAM enzymes are an emerging subgroup of biological catalysts that bind a cobalamin cofactor in addition to the canonical [Fe4S4] cluster characteristic of radical SAM enzymes. Most of the B12-dependent radical SAM enzymes that have been characterized mediated methyltransfer reactions; however, a small number are known to catalyze more diverse reactions such as ring contractions. Thus, Genk is a methyltransferase from the gentamicin C biosynthetic pathway, whereas OxsB catalyzes the oxidative ring contraction of 2'-deoxyadenosine 5'-phosphates to generate an oxetane aldehyde during the biosynthesis of oxetanocin A. The preparation and in vitro characterization of such enzymes is complicated by the presence of two redox sensitive cofactors in addition to challenges in obtaining soluble protein for study. This chapter describes expression, purification and assay methodologies for GenK and OxsB highlighting the use of denaturation/refolding protocols for solubilizing inclusion bodies as well as the use of cluster assembly and cobalamin uptake machinery during in vivo expression.


Assuntos
Produtos Biológicos , S-Adenosilmetionina , Vias Biossintéticas , Metiltransferases/metabolismo , S-Adenosilmetionina/metabolismo , Vitamina B 12/metabolismo
10.
Oxid Med Cell Longev ; 2022: 5696686, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35387262

RESUMO

Cigarette smoke (CS) is a risk factor for chronic obstructive pulmonary disease. We attempted to investigate fully the possible effects of CS on kidney cells. We found that the viability of a human kidney proximal tubular epithelial cell line (HK-2 cells) was decreased after treatment with CS extract (CSE). In particular, the effects of CSE at low concentrations did not change the expression of apoptosis and necrosis. Furthermore, CSE increased autophagy- and fibrosis-related proteins in HK-2 cells. Senescence-related proteins and the senescence-associated secretory phenotype (SASP) increased after HK-2 cells were treated with CSE. In addition, both RNA sequencing and gene set enrichment analysis data revealed that glucose-6-phosphate dehydrogenase (G6PD) in the reactive oxygen species (ROS) pathway is responsible for the changes in CSE-treated HK-2 cells. CSE increased G6PD expression and its activity. Moreover, the inhibition of G6PD activity increased senescence in HK-2 cells. The inhibition of autophagy reinforced senescence in the CSE-treated cells. In a mouse model of CS exposure, CS caused kidney damage, including tubular injury and glomerulosclerosis. CS increased fibrosis, autophagy, and G6PD expression in kidney tissue sections. In conclusion, CS induced G6PD expression, autophagy, fibrosis, and senescence in kidney cells. G6PD has a protective role in CS-induced nephrotoxicity.


Assuntos
Fumar Cigarros , Doença Pulmonar Obstrutiva Crônica , Animais , Autofagia , Fumar Cigarros/efeitos adversos , Células Epiteliais/metabolismo , Fibrose , Glucosefosfato Desidrogenase/metabolismo , Rim/metabolismo , Camundongos , Doença Pulmonar Obstrutiva Crônica/metabolismo , Nicotiana
11.
J Am Chem Soc ; 144(10): 4478-4486, 2022 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-35238201

RESUMO

The biosynthesis of blasticidin S has drawn attention due to the participation of the radical S-adenosyl methionine (SAM) enzyme BlsE. The original assignment of BlsE as a radical-mediated, redox-neutral decarboxylase is unusual because this reaction appears to serve no biosynthetic purpose and would need to be reversed by a subsequent carboxylation step. Furthermore, with the exception of BlsE, all other radical SAM decarboxylases reported to date are oxidative in nature. Careful analysis of the BlsE reaction, however, demonstrates that BlsE is not a decarboxylase but instead a lyase that catalyzes the dehydration of cytosylglucuronic acid (CGA) to form cytosyl-4'-keto-3'-deoxy-d-glucuronic acid, which can rapidly decarboxylate nonenzymatically in vitro. Analysis of substrate isotopologs, fluorinated analogues, as well as computational models based on X-ray crystal structures of the BlsE·SAM (2.09 Å) and BlsE·SAM·CGA (2.62 Å) complexes suggests that BlsE catalysis likely proceeds via direct elimination of water from the CGA C4' α-hydroxyalkyl radical as opposed to 1,2-migration of the C3'-hydroxyl prior to dehydration. Biosynthetic and mechanistic implications of the revised assignment of BlsE are discussed.


Assuntos
Desidratação , S-Adenosilmetionina , Adenosilmetionina Descarboxilase , Humanos , Nucleosídeos , S-Adenosilmetionina/química
12.
Part Fibre Toxicol ; 19(1): 2, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34983566

RESUMO

BACKGROUND: Zinc oxide nanoparticles (ZnONPs) are widely used nanomaterial in personal cosmetics, such as skin creams and sunscreens, due to their whitening properties and strong UV light absorption. However, the safety issues and the hazards of ZnONPs, which can be taken up by the skin and cause skin toxicity, are still unclear. From a chemoprevention point of view, pterostilbene (PT) has been reported to prevent skin damage effectively by its anti-inflammatory and autophagy inducer effect. This study aims to determine the skin toxicity and the potential mechanisms of UVB and ZnONPs exposure and the preventive effect of PT. RESULTS: The co-exposure of UVB and ZnONPs elicit NLRP3 inflammasome activation and pyroptosis in keratinocytes. Furthermore, exposure to both UVB and ZnONPs also disrupts cellular autophagy, which increases cell exosome release. In vivo UVB and ZnONPs exposure triggers skin toxicity, as indicated by increased histological injury, skin thickness and transepidermal water loss. Notably, the NLRP3 inflammasome-mediated pyroptosis are also activated during exposure. Topical application of pterostilbene attenuates NLRP3 inflammasome activation and pyroptosis by decreasing ROS generation and mitochondrial ROS (mtROS) levels. In addition to its antioxidant effect, PT also reversed autophagy abnormalities by restoring normal autophagic flux and decreasing NLRP3 inflammasome-loaded exosome release. CONCLUSIONS: Our findings reveal that ZnONPs induce skin damage in conjunction with UVB exposure. This process involves an interplay of inflammasomes, pyroptosis, autophagy dysfunction, and exosomes in skin toxicity. PT alleviates skin inflammation by regulating the inflammasome-autophagy-exosome pathway, a finding which could prove valuable when further evaluating ZnONPs effects for cosmetic applications.


Assuntos
Nanopartículas , Óxido de Zinco , Autofagia , Inflamassomos , Proteína 3 que Contém Domínio de Pirina da Família NLR , Piroptose , Óxido de Zinco/toxicidade
13.
J Hypertens ; 39(9): 1835-1843, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-34054053

RESUMO

BACKGROUND: Dietary Approaches to Stop Hypertension (DASH)-Sodium trial showed that dietary sodium and potassium affect blood pressure (BP). We aimed to investigate whether dietary sodium and potassium affect short-term BP variability (BPV) in addition to BP. METHODS: A total of 343 participants from the DASH-Sodium trial (age 48.4 ±â€Š9.7, 42.5% men) and 323 individuals from the Jackson Heart Study (JHS) (age 56.7 ±â€Š11.2, 30.7% men) with satisfactory ambulatory BP monitoring records and 24-h urine collection were included. Average real variability (ARV) was calculated as a measure of short-term BPV. RESULTS: By estimating dietary intake from urinary excretion, we observed that higher urinary sodium-to-potassium ratio was significantly associated with higher diastolic ARV in both studies. Among the DASH-Sodium trial, potassium-rich DASH diet alone had insignificant effect on both systolic (-0.1 ±â€Š1.7 mmHg, P = 0.343) or diastolic ARV (-0.2 ±â€Š1.5 mmHg, P = 0.164), whereas combined DASH diet and low sodium intake significantly reduced both systolic (8.5 ±â€Š1.6 vs. 8.9 ±â€Š1.7 mmHg, P = 0.032) and diastolic ARV (7.5 ±â€Š1.5 vs. 7.8 ±â€Š1.6 mmHg, P = 0.025) as compared with control diet and high sodium intake. As the reduction of systolic ARV was majorly derived from the change of mean SBP, diastolic ARV was significantly determined by urinary sodium-to-potassium ratio (ß coefficient ±â€Šstandard error: 0.012 ±â€Š0.004; P = 0.006) after adjusting for age, sex, smoking, mean DBP, BMI, and race. CONCLUSION: Dietary sodium and potassium can jointly modulate short-term BPV in addition to BP. Combined DASH diet and low sodium intake may reduce systolic and diastolic ARV via different mechanisms.


Assuntos
Hipertensão , Sódio , Adulto , Idoso , Pressão Sanguínea , Dieta Hipossódica , Ingestão de Alimentos , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Potássio
14.
Front Oncol ; 11: 620361, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33937026

RESUMO

Colorectal cancer (CRC) is a leading cause of cancer-related deaths. Because of the lack of reliable prognostic and predictive biomarkers for CRC, most patients are often diagnosed at a late stage. The tryptophan-kynurenine pathway plays a crucial role in promoting cancer progression. Kynurenine is considered an oncometabolite in colon cancer, and its downstream metabolites are also associated with CRC. Kynurenine 3-monooxygenase (KMO), a pivotal enzyme that catalyzes kynurenine metabolism, is essential for several cellular processes. In the current study, we explored the role of KMO in CRC. Immunohistochemical results showed that KMO was upregulated in CRC tissues relative to paired healthy tissue and polyps. Moreover, CRC patients with higher KMO expression were associated with higher metastasis and poorer survival rates. Knockdown of KMO decreased the expression of cancer stem cell markers, as well as the sphere-forming, migration, and invasion abilities of CRC cells. Additionally, blockade of the enzymatic activity of KMO using an inhibitor suppressed sphere formation and cell motility in CRC cells. These findings suggest the clinical relevance of KMO in CRC tumorigenesis and aggressiveness.

15.
Environ Health Perspect ; 129(5): 57003, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33956507

RESUMO

BACKGROUND: Understanding the epidemic of chronic kidney disease of uncertain etiology may be critical for health policies and public health responses. Recent studies have shown that microplastics (MPs) contaminate our food chain and accumulate in the gut, liver, kidney, muscle, and so on. Humans manufacture many plastics-related products. Previous studies have indicated that particles of these products have several effects on the gut and liver. Polystyrene (PS)-MPs (PS-MPs) induce several responses, such as oxidative stress, and affect living organisms. OBJECTIVES: The aim of this study was to investigate the effects of PS-MPs in kidney cells in vitro and in vivo. METHODS: PS-MPs were evaluated in human kidney proximal tubular epithelial cells (HK-2 cells) and male C57BL/6 mice. Mitochondrial reactive oxygen species (ROS), endoplasmic reticulum (ER) stress, inflammation, and autophagy were analyzed in kidney cells. In vivo, we evaluated biomarkers of kidney function, kidney ultrastructure, muscle mass, and grip strength, and urine protein levels, as well as the accumulation of PS-MPs in the kidney tissue. RESULTS: Uptake of PS-MPs at different concentrations by HK-2 cells resulted in higher levels of mitochondrial ROS and the mitochondrial protein Bad. Cells exposed to PS-MPs had higher ER stress and markers of inflammation. MitoTEMPO, which is a mitochondrial ROS antioxidant, mitigated the higher levels of mitochondrial ROS, Bad, ER stress, and specific autophagy-related proteins seen with PS-MP exposure. Furthermore, cells exposed to PS-MPs had higher protein levels of LC3 and Beclin 1. PS-MPs also had changes in phosphorylation of mitogen-activated protein kinase (MAPK) and protein kinase B (AKT)/mitogen-activated protein kinase (mTOR) signaling pathways. In an in vivo study, PS-MPs accumulated and the treated mice had more histopathological lesions in the kidneys and higher levels of ER stress, inflammatory markers, and autophagy-related proteins in the kidneys after PS-MPs treatment by oral gavage. CONCLUSIONS: The results suggest that PS-MPs caused mitochondrial dysfunction, ER stress, inflammation, and autophagy in kidney cells and accumulated in HK-2 cells and in the kidneys of mice. These results suggest that long-term PS-MPs exposure may be a risk factor for kidney health. https://doi.org/10.1289/EHP7612.


Assuntos
Rim , Microplásticos , Poliestirenos , Animais , Células Epiteliais/efeitos dos fármacos , Humanos , Rim/citologia , Rim/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Microplásticos/toxicidade , Poliestirenos/toxicidade
16.
Int J Mol Sci ; 22(9)2021 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-33946416

RESUMO

With rapid industrialization, humans produce an increasing number of products. The composition of these products is usually decomposed. However, some substances are not easily broken down and gradually become environmental pollutants. In addition, these substances may cause bioaccumulation, since the substances can be fragmented into micro- and nanoparticles. These particles or their interactions with other toxic matter circulate in humans via the food chain or air. Whether these micro- and nanoparticles interfere with extracellular vesicles (EVs) due to their similar sizes is unclear. Micro- and nanoparticles (MSs and NSs) induce several cell responses and are engulfed by cells depending on their size, for example, particulate matter with a diameter ≤2.5 µm (PM2.5). Autophagy is a mechanism by which pathogens are destroyed in cells. Some artificial materials are not easily decomposed in organisms. How do these cells or tissues respond? In addition, autophagy operates through two pathways (increasing cell death or cell survival) in tumorigenesis. Many MSs and NSs have been found that induce autophagy in various cells and tissues. As a result, this review focuses on how these particles interfere with cells and tissues. Here, we review MSs, NSs, and PM2.5, which result in different autophagy-related responses in various tissues or cells.


Assuntos
Autofagia , Poluentes Ambientais/efeitos adversos , Nanopartículas/efeitos adversos , Material Particulado/efeitos adversos , Animais , Poluentes Ambientais/toxicidade , Vesículas Extracelulares/metabolismo , Vesículas Extracelulares/patologia , Humanos , Nanopartículas/toxicidade , Neoplasias/etiologia , Neoplasias/metabolismo , Neoplasias/patologia , Tamanho da Partícula , Material Particulado/toxicidade
17.
Biochemistry ; 60(7): 537-546, 2021 02 23.
Artigo em Inglês | MEDLINE | ID: mdl-33560833

RESUMO

Oxetanocin-A is an antitumor, antiviral, and antibacterial nucleoside. It is biosynthesized via the oxidative ring contraction of a purine nucleoside co-opted from primary metabolism. This reaction is catalyzed by a B12-dependent radical S-adenosyl-l-methionine (SAM) enzyme, OxsB, and a phosphohydrolase, OxsA. Previous experiments showed that the product of the OxsB/OxsA-catalyzed reaction is an oxetane aldehyde produced alongside an uncharacterized byproduct. Experiments reported herein reveal that OxsB/OxsA complex formation is crucial for the ring contraction reaction and that reduction of the aldehyde intermediate is catalyzed by a nonspecific dehydrogenase from the general cellular pool. In addition, the byproduct is identified as a 1,3-thiazinane adduct between the aldehyde and l-homocysteine. While homocysteine was never included in the OxsB/OxsA assays, the data suggest that it can be generated from SAM via S-adenosyl-l-homocysteine (SAH). Further study revealed that conversion of SAM to SAH is facilitated by OxsB; however, the subsequent conversion of SAH to homocysteine is due to protein contaminants that co-purify with OxsA. Nevertheless, the observed demethylation of SAM to SAH suggests possible methyltransferase activity of OxsB, and substrate methylation was indeed detected in the OxsB-catalyzed reaction. This work is significant because it not only completes the description of the oxetanocin-A biosynthetic pathway but also suggests that OxsB may be capable of methyltransferase activity.


Assuntos
Adenina/análogos & derivados , S-Adenosilmetionina/química , Adenina/biossíntese , Adenina/metabolismo , Biocatálise , Catálise , Desmetilação , Metilação , Estresse Oxidativo , Monoéster Fosfórico Hidrolases/metabolismo , S-Adenosil-Homocisteína/metabolismo , S-Adenosilmetionina/metabolismo
18.
Biotechnol J ; 16(4): e2000311, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33135368

RESUMO

Biomolecules are increasingly attractive templates for the synthesis of functional nanomaterials. Chief among them is the plant tobacco mosaic virus (TMV) due to its high aspect ratio, narrow size distribution, diverse biochemical functionalities presented on the surface, and compatibility with a number of chemical conjugations. These properties are also easily manipulated by genetic modification to enable the synthesis of a range of metallic and non-metallic nanomaterials for diverse applications. This article reviews the characteristics of TMV and related viruses, and their virus-like particle (VLP) derivatives, and how these may be manipulated to extend their use and function. A focus of recent efforts has been on greater understanding and control of the self-assembly processes that drive biotemplate formation. How these features have been exploited in engineering applications such as, sensing, catalysis, and energy storage are briefly outlined. While control of VLP surface features is well-established, fewer tools exist to control VLP self-assembly, which limits efforts to control template uniformity and synthesis of certain templated nanomaterials. However, emerging advances in synthetic biology, machine learning, and other fields promise to accelerate efforts to control template uniformity and nanomaterial synthesis enabling more widescale industrial use of VLP-based biotemplates.


Assuntos
Nanoestruturas , Vírus do Mosaico do Tabaco , Biologia Sintética , Nicotiana , Vírus do Mosaico do Tabaco/genética
19.
Toxics ; 8(4)2020 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-33114531

RESUMO

Current cigarette smoking is associated with chronic kidney disease (CKD) or death from end-stage renal disease (ESRD). Mainstream cigarette smoke includes over 4000 compounds. Among the compounds present in tobacco smoke, nicotine is one of a large number of biologically stable and active compounds present in tobacco. However, the mechanisms by which nicotine exacerbates kidney disease progression have not been identified. It is known that the inflammasomes constitute an important innate immune pathway and contribute to the pathophysiology of diverse kidney diseases. The relationship between inflammasomes and nicotine-induced kidney damage still remains unclear. In the present study, we studied the mechanisms of nicotine-induced nephrotoxicity. We found that nicotine decreased cell viability and induced reactive oxygen species (ROS) generation in human kidney cells. Furthermore, nicotine significantly increased the expression of the alpha7 nicotinic acetylcholine receptor (α7nAChR). Nicotine activated the NLRP6 inflammasome and induced endoplasmic reticulum (ER) stress. Nicotine caused mild apoptosis and necrosis but triggered significant autophagy in human kidney cells. In addition, nicotine induced the NLRP6 inflammasome and autophagy via α7nAChR. In an animal model, the histological analysis in kidney showed evident changes and injury. The results indicated that α7nAChR, IRE1α, LC3 and NLRP6 expression in kidney sections was markedly increased in the nicotine groups. These findings suggest that nicotine causes kidney damage by modulating α7nAChR, NLRP6 inflammasome, ER stress and autophagy.

20.
Int J Mol Sci ; 21(5)2020 Mar 03.
Artigo em Inglês | MEDLINE | ID: mdl-32138322

RESUMO

Plastic products are inexpensive, convenient, and are have many applications in daily life. We overuse plastic-related products and ineffectively recycle plastic that is difficult to degrade. Plastic debris can be fragmented into smaller pieces by many physical and chemical processes. Plastic debris that is fragmented into microplastics or nanoplastics has unclear effects on organismal systems. Recently, this debris was shown to affect biota and to be gradually spreading through the food chain. In addition, studies have indicated that workers in plastic-related industries develop many kinds of cancer because of chronic exposure to high levels of airborne microplastics. Microplastics and nanoplastics are everywhere now, contaminating our water, air, and food chain. In this review, we introduce a classification of plastic polymers, define microplastics and nanoplastics, identify plastics that contaminate food, describe the damage and diseases caused by microplastics and nanoplastics, and the molecular and cellular mechanisms of this damage and disease as well as solutions for their amelioration. Thus, we expect to contribute to the understanding of the effects of microplastics and nanoplastics on cellular and molecular mechanisms and the ways that the uptake of microplastics and nanoplastics are potentially dangerous to our biota. After understanding the issues, we can focus on how to handle the problems caused by plastic overuse.


Assuntos
Nanoestruturas/química , Plásticos/química , Arabidopsis/efeitos dos fármacos , Arabidopsis/metabolismo , Genótipo , Humanos , Mutação/genética , Transdução de Sinais/efeitos dos fármacos , Cloreto de Sódio/farmacologia
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