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1.
Mol Nutr Food Res ; 68(10): e2300347, 2024 May.
Artigo em Inglês | MEDLINE | ID: mdl-38712453

RESUMO

Skeletal muscle can undergo detrimental changes in various diseases, leading to muscle dysfunction and atrophy, thus severely affecting people's lives. Along with exercise, there is a growing interest in the potential of nutritional support against muscle atrophy. This review provides a brief overview of the molecular mechanisms driving skeletal muscle atrophy and summarizes recent advances in nutritional interventions for preventing and treating muscle atrophy. The nutritional supplements include amino acids and their derivatives (such as leucine, ß-hydroxy, ß-methylbutyrate, and creatine), various antioxidant supplements (like Coenzyme Q10 and mitoquinone, resveratrol, curcumin, quercetin, Omega 3 fatty acids), minerals (such as magnesium and selenium), and vitamins (such as vitamin B, vitamin C, vitamin D, and vitamin E), as well as probiotics and prebiotics (like Lactobacillus, Bifidobacterium, and 1-kestose). Furthermore, the study discusses the impact of a combined approach involving nutritional support and physical therapy to prevent muscle atrophy, suggests appropriate multi-nutritional and multi-modal interventions based on individual conditions to optimize treatment outcomes, and enhances the recovery of muscle function for patients. By understanding the molecular mechanisms behind skeletal muscle atrophy and implementing appropriate interventions, it is possible to enhance the recovery of muscle function and improve patients' quality of life.


Assuntos
Suplementos Nutricionais , Músculo Esquelético , Atrofia Muscular , Humanos , Atrofia Muscular/prevenção & controle , Atrofia Muscular/dietoterapia , Músculo Esquelético/efeitos dos fármacos , Probióticos/administração & dosagem , Antioxidantes , Prebióticos , Vitaminas , Animais
2.
Inflammopharmacology ; 32(2): 1633-1646, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38451396

RESUMO

Improving inflammation may serve as useful therapeutic interventions for the hindlimb unloading-induced disuse muscle atrophy. Celecoxib is a selective non-steroidal anti-inflammatory drug. We aimed to determine the role and mechanism of celecoxib in hindlimb unloading-induced disuse muscle atrophy. Celecoxib significantly attenuated the decrease in soleus muscle mass, hindlimb muscle function and the shift from slow- to fast-twitch muscle fibers caused by hindlimb unloading in rats. Importantly, celecoxib inhibited the increased expression of inflammatory factors, macrophage infiltration in damaged soleus muscle. Mechanistically, Celecoxib could significantly reduce oxidative stress and endoplasmic reticulum stress in soleus muscle of unloaded rats. Furthermore, celecoxib inhibited muscle proteolysis by reducing the levels of MAFbx, MuRF1, and autophagy related proteins maybe by inhibiting the activation of pro-inflammatory STAT3 pathway in vivo and in vitro. This study is the first to demonstrate that celecoxib can attenuate disuse muscle atrophy caused by hindlimb unloading via suppressing inflammation, oxidative stress and endoplasmic reticulum stress probably, improving target muscle function and reversing the shift of muscle fiber types by inhibiting STAT3 pathways-mediated inflammatory cascade. This study not only enriches the potential molecular regulatory mechanisms, but also provides new potential therapeutic targets for disuse muscle atrophy.


Assuntos
Elevação dos Membros Posteriores , Atrofia Muscular , Animais , Ratos , Celecoxib/farmacologia , Celecoxib/uso terapêutico , Elevação dos Membros Posteriores/efeitos adversos , Elevação dos Membros Posteriores/fisiologia , Músculo Esquelético/metabolismo , Atrofia Muscular/tratamento farmacológico , Atrofia Muscular/etiologia , Atrofia Muscular/metabolismo , Estresse Oxidativo
3.
Front Pharmacol ; 15: 1344276, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38313305

RESUMO

Aim: Diabetic sarcopenia leads to disability and seriously affects the quality of life. Currently, there are no effective therapeutic strategies for diabetic sarcopenia. Our previous studies have shown that inflammation plays a critical role in skeletal muscle atrophy. Interestingly, the connection between chronic inflammation and diabetic complications has been revealed. However, the effects of non-steroidal anti-inflammatory drug celecoxib on diabetic sarcopenia remains unclear. Materials and Methods: The streptozotocin (streptozotocin)-induced diabetic sarcopenia model was established. Rotarod test and grip strength test were used to assess skeletal muscle function. Hematoxylin and eosin and immunofluorescence staining were performed to evaluate inflammatory infiltration and the morphology of motor endplates in skeletal muscles. Succinate dehydrogenase (SDH) staining was used to determine the number of succinate dehydrogenase-positive muscle fibers. Dihydroethidium staining was performed to assess the levels of reactive oxygen species (ROS). Western blot was used to measure the levels of proteins involved in inflammation, oxidative stress, endoplasmic reticulum stress, ubiquitination, and autophagic-lysosomal pathway. Transmission electron microscopy was used to evaluate mitophagy. Results: Celecoxib significantly ameliorated skeletal muscle atrophy, improving skeletal muscle function and preserving motor endplates in diabetic mice. Celecoxib also decreased infiltration of inflammatory cell, reduced the levels of IL-6 and TNF-α, and suppressed the activation of NF-κB, Stat3, and NLRP3 inflammasome pathways in diabetic skeletal muscles. Celecoxib decreased reactive oxygen species levels, downregulated the levels of Nox2 and Nox4, upregulated the levels of GPX1 and Nrf2, and further suppressed endoplasmic reticulum stress by inhibiting the activation of the Perk-EIF-2α-ATF4-Chop in diabetic skeletal muscles. Celecoxib also inhibited the levels of Foxo3a, Fbx32 and MuRF1 in the ubiquitin-proteasome system, as well as the levels of BNIP3, Beclin1, ATG7, and LC3Ⅱ in the autophagic-lysosomal system, and celecoxib protected mitochondria and promoted mitochondrial biogenesis by elevating the levels of SIRT1 and PGC1-α, increased the number of SDH-positive fibers in diabetic skeletal muscles. Conclusion: Celecoxib improved diabetic sarcopenia by inhibiting inflammation, oxidative stress, endoplasmic reticulum stress, and protecting mitochondria, and subsequently suppressing proteolytic systems. Our study provides evidences for the molecular mechanism and treatment of diabetic sarcopenia, and broaden the way for the new use of celecoxib in diabetic sarcopenia.

4.
Regen Biomater ; 11: rbae009, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38420353

RESUMO

With the rapid development of materials science and tissue engineering, a variety of biomaterials have been used to construct tissue engineering scaffolds. Due to the performance limitations of single materials, functional composite biomaterials have attracted great attention as tools to improve the effectiveness of biological scaffolds for tissue repair. In recent years, metal-organic frameworks (MOFs) have shown great promise for application in tissue engineering because of their high specific surface area, high porosity, high biocompatibility, appropriate environmental sensitivities and other advantages. This review introduces methods for the construction of MOFs-based functional composite scaffolds and describes the specific functions and mechanisms of MOFs in repairing damaged tissue. The latest MOFs-based functional composites and their applications in different tissues are discussed. Finally, the challenges and future prospects of using MOFs-based composites in tissue engineering are summarized. The aim of this review is to show the great potential of MOFs-based functional composite materials in the field of tissue engineering and to stimulate further innovation in this promising area.

5.
Eye (Lond) ; 38(4): 723-729, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37749377

RESUMO

OBJECTIVES: To evaluate the therapeutic efficacy and safety of obinutuzumab in remission induction for IgG4-related ophthalmic disease (IgG4-ROD) patients. METHODS: Eight IgG4-ROD patients were retrospectively enrolled. They were intravenously administered 1000 mg obinutuzumab at baseline and examined for changes in physical signs, orbital structure imaging parameters, IgG4-related disease responder index (IgG4-RD RI), serological index, and adverse events during treatment. The number of treatment sessions was based on treatment response. RESULTS: The mean IgG4-RD RI scores of all patients at baseline (7.75 ± 2.92) and after treatment (2.00 ± 0.76) were highly significantly different (P < 0.001). Six patients achieved complete remission (CR) (75%) and two patients achieved partial remission (25%). The mean serum IgG4 levels at baseline (9.45 ± 6.95 g/L) and after treatment (1.55 ± 1.09 g/L) showed a mean decrease of 83% (P = 0.0079). The serum IgG4 level correlated well with IgG4-RD RI at baseline and that after each treatment (r = 0.852, P < 0.01; r = 0.78, P < 0.001). In patients with CR, the serum IgG4 levels at baseline correlated positively with dose numbers required for CR (r = 0.86, P < 0.05). Five patients (62.5%) experienced infusion-related reactions (IRRs) during the first obinutuzumab infusion, while only one (12.5%) experienced IRRs during all subsequent eight infusions. CONCLUSION: Obinutuzumab is a safe and promising therapeutic option for IgG4-ROD. It rapidly reduces ocular inflammation and serum IgG4 levels to avoid excessive corticosteroid usage and reduce potential risk of adverse events.


Assuntos
Anticorpos Monoclonais Humanizados , Doenças Autoimunes , Doença Relacionada a Imunoglobulina G4 , Humanos , Doença Relacionada a Imunoglobulina G4/tratamento farmacológico , Estudos Retrospectivos , Glucocorticoides/uso terapêutico , Doenças Autoimunes/tratamento farmacológico , Resultado do Tratamento , Indução de Remissão , Imunoglobulina G/uso terapêutico
6.
Mol Neurobiol ; 2023 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-38102515

RESUMO

Amyotrophic lateral sclerosis (ALS) is a common neurodegenerative disease, accompanied by the gradual loss of motor neuron, even life-threatening. However, the pathogenesis, early diagnosis, and effective strategies of ALS are not yet completely understood. In this study, the function of differentially expressed genes (DEGs) in non-neuronal cells of the primary motor cortex of ALS patients (DATA1), the brainstem of SOD1 mutant ALS mice (DATA2), and the whole blood tissue of ALS patients (DATA3) were explored. The results showed that the functions of DEGs in non-neuronal cells were mainly related to energy metabolism (such as oxidative phosphorylation) and protein synthesis. In non-neuronal cells, six upregulated DEGs (HSPA8, SOD1, CALM1, CALM2, NEFL, COX6C) and three downregulated DEGs (SNRNP70, HSPA1A, HSPA1B) might be key factors in regulating ALS. Microglia played a key role in the development of ALS. The expression of SOD1 and TUBA4A in microglia in DATA1 was significantly increased. The integration analysis of DEGs in DATA1 and DATA2 showed that SOD1 and CALM1 might be potential biomarkers. The integration analysis of DEGs in DATA1 and DATA3 showed that CALM2 and HSPA1A might be potential biomarkers. Cell interaction showed that the interaction between microglia and other cells was reduced in high oxidative phosphorylation states, which might be a risk factor in ALS. Our research provided evidence for the pathogenesis, early diagnosis, and potential targeted therapy for ALS.

7.
J Transl Med ; 21(1): 845, 2023 11 23.
Artigo em Inglês | MEDLINE | ID: mdl-37996930

RESUMO

BACKGROUND: Denervation-induced muscle atrophy is complex disease involving multiple biological processes with unknown mechanisms. N6-methyladenosine (m6A) participates in skeletal muscle physiology by regulating multiple levels of RNA metabolism, but its impact on denervation-induced muscle atrophy is still unclear. Here, we aimed to explore the changes, functions, and molecular mechanisms of m6A RNA methylation during denervation-induced muscle atrophy. METHODS: During denervation-induced muscle atrophy, the m6A immunoprecipitation sequencing (MeRIP-seq) as well as enzyme-linked immunosorbent assay analysis were used to detect the changes of m6A modified RNAs and the involved biological processes. 3-deazidenosine (Daa) and R-2-hydroxyglutarate (R-2HG) were used to verify the roles of m6A RNA methylation. Through bioinformatics analysis combined with experimental verification, the regulatory roles and mechanisms of m6A RNA methylation had been explored. RESULTS: There were many m6A modified RNAs with differences during denervation-induced muscle atrophy, and overall, they were mainly downregulated. After 72 h of denervation, the biological processes involved in the altered mRNA with m6A modification were mainly related to zinc ion binding, ubiquitin protein ligase activity, ATP binding and sequence-specific DNA binding and transcription coactivator activity. Daa reduced overall m6A levels in healthy skeletal muscles, which reduced skeletal muscle mass. On the contrary, the increase in m6A levels mediated by R-2HG alleviated denervation induced muscle atrophy. The m6A RNA methylation regulated skeletal muscle mass through ubiquitin-proteasome pathway. CONCLUSION: This study indicated that decrease in m6A RNA methylation was a new symptom of denervation-induced muscle atrophy, and confirmed that targeting m6A alleviated denervation-induced muscle atrophy.


Assuntos
Atrofia Muscular , Complexo de Endopeptidases do Proteassoma , Humanos , Metilação , Complexo de Endopeptidases do Proteassoma/metabolismo , Atrofia Muscular/genética , Atrofia Muscular/metabolismo , RNA/metabolismo , Denervação , Ubiquitinas/metabolismo
9.
Biochem Pharmacol ; 218: 115872, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37865142

RESUMO

Myasthenia gravis (MG) is a type of autoimmune disease caused by the blockage of neuromuscular junction transmission owing to the attack of autoantibodies on transmission-related proteins. Related antibodies, such as anti-AChR, anti-MuSK and anti-LRP4 antibodies, can be detected in most patients with MG. Although traditional therapies can control most symptoms, several challenges remain to be addressed, necessitating the development of more effective and safe treatment strategies for MG. With the in-depth exploration on the mechanism and immune targets of MG, effective therapies, especially therapies using biologicals, have been reported recently. Given the important roles of immune cells, cytokines and intercellular interactions in the pathological process of MG, B-cell targeted therapy, T-cell targeted therapy, proteasome inhibitors targeting plasma cell, complement inhibitors, FcRn inhibitors have been developed for the treatment of MG. Although these novel therapies exert good therapeutic effects, they may weaken the immunity and increase the risk of infection in MG patients. This review elaborates on the pathogenesis of MG and discusses the advantages and disadvantages of the strategies of traditional treatment and biologicals. In addition, this review emphasises that combined therapy may have better therapeutic effects and reducing the risk of side effects of treatments, which has great prospects for the treatment of MG. With the deepening of research on immunotherapy targets in MG, novel opportunities and challenges in the treatment of MG will be introduced.


Assuntos
Miastenia Gravis , Receptores Proteína Tirosina Quinases , Humanos , Receptores Proteína Tirosina Quinases/metabolismo , Miastenia Gravis/tratamento farmacológico , Miastenia Gravis/diagnóstico , Junção Neuromuscular/metabolismo , Autoanticorpos/metabolismo , Imunoterapia
10.
Biochem Pharmacol ; 214: 115664, 2023 08.
Artigo em Inglês | MEDLINE | ID: mdl-37331636

RESUMO

Oxidative stress, inflammation, mitochondrial dysfunction, reduced protein synthesis, and increased proteolysis are all critical factors in the process of muscle atrophy. In particular, oxidative stress is the key factor that triggers skeletal muscle atrophy. It is activated in the early stages of muscle atrophy and can be regulated by various factors. The mechanisms of oxidative stress in the development of muscle atrophy have not been completely elucidated. This review provides an overview of the sources of oxidative stress in skeletal muscle and the correlation of oxidative stress with inflammation, mitochondrial dysfunction, autophagy, protein synthesis, proteolysis, and muscle regeneration in muscle atrophy. Additionally, the role of oxidative stress in skeletal muscle atrophy caused by several pathological conditions, including denervation, unloading, chronic inflammatory diseases (diabetes mellitus, chronic kidney disease, chronic heart failure, and chronic obstructive pulmonary disease), sarcopenia, hereditary neuromuscular diseases (spinal muscular atrophy, amyotrophic lateral sclerosis, and Duchenne muscular dystrophy), and cancer cachexia, have been discussed. Finally, this review proposes the alleviation oxidative stress using antioxidants, Chinese herbal extracts, stem cell and extracellular vesicles as a promising therapeutic strategy for muscle atrophy. This review will aid in the development of novel therapeutic strategies and drugs for muscle atrophy.


Assuntos
Atrofia Muscular , Sarcopenia , Humanos , Atrofia Muscular/metabolismo , Estresse Oxidativo , Músculo Esquelético/metabolismo , Sarcopenia/tratamento farmacológico , Sarcopenia/metabolismo , Sarcopenia/patologia , Antioxidantes/metabolismo , Doença Crônica
11.
J Neurol ; 270(8): 3733-3749, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37258941

RESUMO

Duchenne muscular dystrophy (DMD) is a severe, progressive, muscle-wasting disease, characterized by progressive deterioration of skeletal muscle that causes rapid loss of mobility. The failure in respiratory and cardiac muscles is the underlying cause of premature death in most patients with DMD. Mutations in the gene encoding dystrophin result in dystrophin deficiency, which is the underlying pathogenesis of DMD. Dystrophin-deficient myocytes are dysfunctional and vulnerable to injury, triggering a series of subsequent pathological changes. In this review, we detail the molecular mechanism of DMD, dystrophin deficiency-induced muscle cell damage (oxidative stress injury, dysregulated calcium homeostasis, and sarcolemma instability) and other cell damage and dysfunction (neuromuscular junction impairment and abnormal differentiation of muscle satellite). We also describe aberrant function of other cells and impaired muscle regeneration due to deterioration of the muscle microenvironment, and dystrophin deficiency-induced multiple organ dysfunction, while summarizing the recent advances in the treatment of DMD.


Assuntos
Distrofia Muscular de Duchenne , Humanos , Distrofia Muscular de Duchenne/genética , Distrofia Muscular de Duchenne/terapia , Distrofina/genética , Músculo Esquelético , Mutação , Junção Neuromuscular/patologia
12.
Int J Biol Sci ; 19(5): 1579-1596, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37056927

RESUMO

The decreased expression and dysfunction of glucose transporter 4 (GLUT4), the insulin-responsive glucose transporter, are closely related to the occurrence of insulin resistance (IR). To improve the expression of GLUT4 may represent a promising strategy to prevent and treat IR and type 2 diabetes (T2DM). Here, we demonstrate that the natural compound tectorigenin (TG) enhances GLUT4 expression, glucose uptake and insulin responsiveness via activating AMP-activated protein kinase (AMPK)/myocyte enhancer factor 2 (MEF2) signaling in both normal and IR skeletal muscle cells and tissues. Accordingly, prophylactic and therapeutic uses of TG can significantly ameliorate IR and hyperglycemia in T2DM mice. Mechanistically, we identify protein kinase A catalytic subunit α (PKACα) as the target of TG to increase GLUT4 expression and TG-PKACα binding promotes the dissociation of PKACα from the regulatory subunits, leading to the activation of PKA/AMPK signaling. PKACα knockdown in local quadriceps muscles almost completely abolished the therapeutic effects of TG on IR and T2DM, as well as the enhancement on AMPK signaling and GLUT4 expression in skeletal muscle. This study supports TG as a new drug candidate to treat IR and its related diseases, but also enriches our knowledge of PKA signaling in glucose metabolism in skeletal muscle.


Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Camundongos , Animais , Resistência à Insulina/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Músculo Esquelético/metabolismo , Insulina/metabolismo , Transportador de Glucose Tipo 4/genética , Transportador de Glucose Tipo 4/metabolismo , Glucose/metabolismo
13.
Cell Death Dis ; 14(1): 13, 2023 01 11.
Artigo em Inglês | MEDLINE | ID: mdl-36631457

RESUMO

Recurrence and metastasis are the main causes of breast cancer (BRCA)-related death and remain a challenge for treatment. In-depth research on the molecular mechanisms underlying BRCA progression has been an important basis for developing precise biomarkers and therapy targets for early prediction and treatment of progressed BRCA. Herein, we identified FERM domain-containing protein 3 (FRMD3) as a novel potent BRCA tumor suppressor which is significantly downregulated in BRCA clinical tissue and cell lines, and low FRMD3 expression has been closely associated with progressive BRCA and shortened survival time in BRCA patients. Overexpression and knockdown experiments have revealed that FRMD3 significantly inhibits BRCA cell proliferation, migration, and invasion in vitro and suppresses BRCA xenograft growth and metastasis in vivo as well. Mechanistically, FRMD3 can interact with vimentin and ubiquitin protein ligase E3A(UBE3A) to induce the polyubiquitin-mediated proteasomal degradation of vimentin, which subsequently downregulates focal adhesion complex proteins and pro-cancerous signaling activation, thereby resulting in cytoskeletal rearrangement and defects in cell morphology and focal adhesion. Further evidence has confirmed that FRMD3-mediated vimentin degradation accounts for the anti-proliferation and anti-metastasis effects of FRMD3 on BRCA. Moreover, the N-terminal ubiquitin-like domain of FRMD3 has been identified as responsible for FRMD3-vimentin interaction through binding the head domain of vimentin and the truncated FRMD3 with the deletion of ubiquitin-like domain almost completely loses the anti-BRCA effects. Taken together, our study indicates significant potential for the use of FRMD3 as a novel prognosis biomarker and a therapeutic target of BRCA and provides an additional mechanism underlying the degradation of vimentin and BRCA progression.


Assuntos
Neoplasias da Mama , Adesões Focais , Proteínas Supressoras de Tumor , Vimentina , Feminino , Humanos , Neoplasias da Mama/metabolismo , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células , Adesões Focais/metabolismo , Regulação Neoplásica da Expressão Gênica , Ubiquitina/metabolismo , Ubiquitinação , Vimentina/metabolismo , Proteínas Supressoras de Tumor/metabolismo
14.
Int J Biol Sci ; 17(13): 3493-3507, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34512161

RESUMO

Histone deacetylases (HDACs) exhibit increased expression in cancer and promote oncogenesis via the acetylation of or interactions with key transcriptional regulators. HDAC inhibitors (HDACis) decrease HDAC activity to selectively inhibit the occurrence and development of tumors. Our study screened and obtained a new HDACi structure. In vitro experiments have showed that among the leads, Z31216525 significantly inhibited the proliferation and induced the apoptosis of epithelial ovarian cancer (EOC) cells. In vivo experiments demonstrated that compared to the control, Z31216525 significantly inhibited tumor growth and showed very low toxicity. Further mechanistic studies revealed that Z31216525 may exert an antitumor effect by inhibiting the expression of the c-Myc gene. Collectively, our studies identified a novel HDACi that is expected to become a new potential therapeutic drug for EOC and has important value for the design of new HDACi structures.


Assuntos
Inibidores de Histona Desacetilases/uso terapêutico , Neoplasias Ovarianas/tratamento farmacológico , Animais , Feminino , Genes myc , Células HeLa , Células Hep G2 , Inibidores de Histona Desacetilases/química , Humanos , Camundongos Nus , Simulação de Acoplamento Molecular , Mapas de Interação de Proteínas , Ensaios Antitumorais Modelo de Xenoenxerto
15.
Nano Lett ; 21(15): 6540-6548, 2021 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-34286999

RESUMO

Single-molecule junctions (SMJs) have been fabricated using layers generated by diazonium electroreduction. This process creates a C-Au covalent bond between the molecule and the electrode. Rigid oligomers of variable length, based on porphyrin derivatives in their free base or cobalt complex forms, have been grafted on the surface. The conductance of the oligomers has been studied by a scanning tunneling microscopy break junction (STM-bj) technique and G(t) measurements, and the lifetime of the SMJs has been investigated. The conductance histograms indicate that charge transport in the porphyrins is relatively efficient and influenced by the presence of the cobalt center. With both systems, random telegraph G(t) signals are easily recorded, showing SMJ on/off states. The SMJs then stabilize and exhibit a surprisingly long lifetime around 10 s, and attenuation plots, obtained by both G(t) and STM-bj measurements, give identical values. This work shows that highly stable SMJs can be prepared using a diazonium grafting approach.

16.
J Hazard Mater ; 405: 124203, 2021 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-33268207

RESUMO

Plasma catalysis technology has been demonstrated to be effective for the decomposition of volatile organic compounds (VOCs). It is highly desired to explore the effect of supports on VOCs oxidation processes during plasma catalysis. In this work, four supports of SiO2, ZSM-5-300, ZSM-5-38 and γ-Al2O3 loading with transition metal oxides were used to decompose toluene at room temperature. It was found that toluene decomposition with 1 wt%Mn/γ-Al2O3 was highest, which was strongly proportional to the ozone decomposition ability of the catalyst. The plasma catalytic decomposition of toluene over 1 wt% MnO2 on different supports were characterized using in situ plasma diffuse reflectance infrared Fourier transform spectrometer. The results showed that 1 wt%Mn/γ-Al2O3 could further catalyze toluene to carbonate and bicarbonate via the breakage of C-C bonds from benzoic acid, while that was difficult for 1 wt% Mn/SiO2, 1 wt%Mn/ZSM-5-300 and 1 wt%Mn/ZSM-5-38. The reaction mechanism of toluene decomposition on different catalysts were proposed.

17.
Nano Lett ; 20(9): 6899-6907, 2020 Sep 09.
Artigo em Inglês | MEDLINE | ID: mdl-32786941

RESUMO

Thin layers of cobalt and ruthenium polypyridyl-oligomers with thicknesses between 2 and 8 nm were deposited on gold by electrochemical reduction of diazonium salts. A scanning tunneling microscope was used to create single-molecule junctions (SMJs). The charge transport properties of the Au-[Co(tpy)2]n-Au (n = 1-4) SMJs do not depend markedly on the oligomer length, have an extremely low attenuation factor (ß âˆ¼ 0.19 nm-1), and do not show a thickness-dependent transition between two mechanisms. Resonant charge transport is proposed as the main transport mechanism. The SMJ conductance decreases by 1 order of magnitude upon changing the metal from Co to Ru. In Au-[Ru(tpy)2]n-Au and Au-[Ru(bpy)3]n-Au SMJs, a charge transport transition from direct tunneling to hopping is evidenced by a break in the length-dependent ß-plot. The three different mechanisms observed are a clear molecular signature on transport in SMJs. Most importantly, these results are in good agreement with those obtained on large-area molecular junctions.

18.
J Biol Chem ; 295(37): 12975-12992, 2020 09 11.
Artigo em Inglês | MEDLINE | ID: mdl-32690606

RESUMO

Pancreas/duodenum homeobox protein 1 (PDX1) is an important transcription factor that regulates islet ß-cell proliferation, differentiation, and function. Reduced expression of PDX1 is thought to contribute to ß-cell loss and dysfunction in diabetes. Thus, promoting PDX1 expression can be an effective strategy to preserve ß-cell mass and function. Previously, we established a PDX1 promoter-dependent luciferase system to screen agents that can promote PDX1 expression. Natural compound tectorigenin (TG) was identified as a promising candidate that could enhance the activity of the promoter for the PDX1 gene. In this study, we first demonstrated that TG could promote the expression of PDX1 in ß-cells via activating extracellular signal-related kinase (ERK), as indicated by increased phosphorylation of ERK; this effect was observed under either normal or glucotoxic/lipotoxic conditions. We then found that TG could suppress induced apoptosis and improved the viability of ß-cells under glucotoxicity and lipotoxicity by activation of ERK and reduction of reactive oxygen species and endoplasmic reticulum (ER) stress. These effects held true in vivo as well: prophylactic or therapeutic use of TG could obviously inhibit ER stress and decrease islet ß-cell apoptosis in the pancreas of mice given a high-fat/high-sucrose diet (HFHSD), thus dramatically maintaining or restoring ß-cell mass and islet size, respectively. Accordingly, both prophylactic and therapeutic use of TG improved HFHSD-impaired glucose metabolism in mice, as evidenced by ameliorating hyperglycemia and glucose intolerance. Taken together, TG, as an agent promoting PDX1 expression exhibits strong protective effects on islet ß-cells both in vitro and in vivo.


Assuntos
Estresse do Retículo Endoplasmático/efeitos dos fármacos , Regulação da Expressão Gênica/efeitos dos fármacos , Proteínas de Homeodomínio/biossíntese , Células Secretoras de Insulina/metabolismo , Isoflavonas/farmacologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Regiões Promotoras Genéticas , Transativadores/biossíntese , Animais , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Glucose/metabolismo , Células HEK293 , Humanos , Masculino , Camundongos , Ratos
19.
J Hazard Mater ; 396: 122730, 2020 09 05.
Artigo em Inglês | MEDLINE | ID: mdl-32344365

RESUMO

Plasma-catalytic oxidation of particulate matter (PM) has potential applications for diesel exhaust cleaning. There is a grand requirement to explore the mechanism of carbonaceous PM oxidation for the development of plasma catalysts. Herein, Au/γ-Al2O3 was used to catalyze the gasification of the graphitic carbon. A modified diffuse reflectance infrared Fourier transform spectrometer equipped with a mass spectrometer was originally utilized to in situ characterize the surface intermediates of graphite on Au/γ-Al2O3 and the gaseous products during the discharges processes in the O2-He balanced gases. It was found that O atoms and O3 play important roles in the formation of surface oxygen complexes (SOCs) and facilitate the gasification of SOCs to CO2 in the presence of Au/γ-Al2O3. The findings are helpful to understand the plasma-catalytic oxidation mechanism of PM and further develop efficient plasma catalysts.

20.
Int J Biol Sci ; 15(7): 1472-1487, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31337977

RESUMO

A decrease in islet ß-cell mass is closely associated with the development and progression of diabetes. Therefore, protection against ß-cell loss is an essential measure to prevent and treat diabetes. In this study, we investigated the protective effects of non-photoactivated hypericin, a natural compound, on ß-cells both in vitro and in vivo. In vitro, hypericin greatly improved INS-1 cell viability under high-glucose and high-fatty-acid conditions by inhibiting glucotoxicity- and lipotoxicity-induced apoptosis and nitric oxide (NO) production. Then, we further demonstrated that hypericin elicited its protective effects against glucotoxicity and lipotoxicity in INS-1 cells by attenuating the reduction in pancreatic duodenal homeobox-1 (PDX1) expression and Erk activity. In vivo, prophylactic or therapeutic use of hypericin inhibited islet ß-cell apoptosis and enhanced the anti-oxidative ability of pancreatic tissue in high-fat/high-sucrose (HFHS)-fed mice, thus alleviating ß-cell loss and maintaining or improving ß-cell mass and islet size. More importantly, hypericin treatment decreased fasting blood glucose, improved glucose intolerance and insulin intolerance, and alleviated hyperinsulinaemia in HFHS-fed mice. Therefore, hypericin showed preventive and therapeutic effects against HFHS-induced onset of type II diabetes in mice. Hypericin possesses great potential for development as an anti-diabetes drug in the future.


Assuntos
MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Glucose/metabolismo , Proteínas de Homeodomínio/metabolismo , Células Secretoras de Insulina/metabolismo , Perileno/análogos & derivados , Transativadores/metabolismo , Animais , Antracenos , Antioxidantes/metabolismo , Apoptose , Linhagem Celular , Sobrevivência Celular , Diabetes Mellitus Tipo 2/metabolismo , Diabetes Mellitus Tipo 2/fisiopatologia , Inibidores Enzimáticos/farmacologia , Ácidos Graxos/química , Células Secretoras de Insulina/efeitos dos fármacos , Insulinoma/metabolismo , Lipídeos/química , Sistema de Sinalização das MAP Quinases , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Óxido Nítrico/metabolismo , Perileno/farmacologia , Ratos
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