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1.
FASEB J ; 34(1): 474-493, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31914704

RESUMO

The RhoA/ROCK-mediated actin cytoskeleton dynamics have been implicated in adipogenesis. The two ROCK isoforms, ROCK1 and ROCK2, are highly homologous. The contribution of ROCK2 to adipogenesis in vivo has not been elucidated. The present study aimed at the in vivo and in vitro roles of ROCK2 in the regulation of adipogenesis and the development of obesity. We performed molecular, histological, and metabolic analyses in ROCK2+/- and ROCK2+/KD mouse models, the latter harboring an allele with a kinase-dead (KD) mutation. Both ROCK2+/- and ROCK2+/KD mouse models showed a lean body mass phenotype during aging, associated with increased amounts of beige cells in subcutaneous white adipose tissue (sWAT) and increased thermogenic gene expression in all fat depots. ROCK2+/- mice on a high-fat diet showed increased energy expenditure accompanying by reduced obesity, and improved insulin sensitivity. In vitro differentiated ROCK2+/- stromal-vascular (SV) cells revealed increased beige adipogenesis associated with increased thermogenic gene expressions. Treatment with a selective ROCK2 inhibitor, KD025, to inhibit ROCK2 activity in differentiated SV cells reproduced the pro-beige phenotype of ROCK2+/- SV cells. In conclusion, ROCK2 activity-mediated actin cytoskeleton dynamics contribute to the inhibition of beige adipogenesis in WAT, and also promotes age-related and diet-induced fat mass gain and insulin resistance.


Assuntos
Adipogenia/fisiologia , Tecido Adiposo Marrom/fisiologia , Tecido Adiposo Branco/fisiologia , Resistência à Insulina , Obesidade/fisiopatologia , Termogênese/fisiologia , Quinases Associadas a rho/fisiologia , Animais , Diferenciação Celular , Dieta Hiperlipídica/efeitos adversos , Metabolismo Energético , Camundongos , Camundongos Knockout , Obesidade/etiologia , Transdução de Sinais
2.
Small ; 15(47): e1901899, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31639277

RESUMO

One major challenge that limits the applications of 2D semiconductors is the detrimental electronic trap states caused by vacancies. Here using grand-canonical density functional theory calculations, a novel approach is demonstrated that uses aqueous electrochemistry to eliminate the trap states of the vacancies in 2D transition metal dichalcogenides while leaving the perfect part of the material intact. The success of this electrochemical approach is based on the selectivity control by the electrode potential and the isovalence between oxygen and chalcogen. Motivated by these results, electrochemical conditions are further identified to functionalize the vacancies by incorporating various single metal atoms, which can bring in magnetism, tune carrier concentration/polarity, and/or activate single-atom catalysis, enabling a wide range of potential applications. These approaches may be generalized to other 2D materials. The results open up a new avenue for improving the properties and extending the applications of 2D materials.

3.
Proc Natl Acad Sci U S A ; 116(38): 18815-18821, 2019 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-31467166

RESUMO

Flexible and low-cost poly(ethylene oxide) (PEO)-based electrolytes are promising for all-solid-state Li-metal batteries because of their compatibility with a metallic lithium anode. However, the low room-temperature Li-ion conductivity of PEO solid electrolytes and severe lithium-dendrite growth limit their application in high-energy Li-metal batteries. Here we prepared a PEO/perovskite Li3/8Sr7/16Ta3/4Zr1/4O3 composite electrolyte with a Li-ion conductivity of 5.4 × 10-5 and 3.5 × 10-4 S cm-1 at 25 and 45 °C, respectively; the strong interaction between the F- of TFSI- (bis-trifluoromethanesulfonimide) and the surface Ta5+ of the perovskite improves the Li-ion transport at the PEO/perovskite interface. A symmetric Li/composite electrolyte/Li cell shows an excellent cyclability at a high current density up to 0.6 mA cm-2 A solid electrolyte interphase layer formed in situ between the metallic lithium anode and the composite electrolyte suppresses lithium-dendrite formation and growth. All-solid-state Li|LiFePO4 and high-voltage Li|LiNi0.8Mn0.1Co0.1O2 batteries with the composite electrolyte have an impressive performance with high Coulombic efficiencies, small overpotentials, and good cycling stability.

4.
FASEB J ; 33(6): 7348-7362, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-30848941

RESUMO

In this study, we investigated the pathophysiological impact of Rho-associated coiled-coil-containing protein kinase (ROCK)1 and ROCK2 double deletion vs. single deletion on cardiac remodeling. Utilizing a cardiomyocyte-specific and tamoxifen-inducible MerCreMer recombinase (MCM), 3 mouse lines (MCM/ROCK1fl/fl/ROCK2fl/fl, MCM/ROCK1fl/fl, and MCM/ROCK2fl/fl) were generated. As early as 5 d after inducible deletion, the double ROCK knockout hearts exhibited reduced phosphorylation of myosin light chain (MLC) and focal adhesion kinase (FAK), supporting a role for ROCK activity in regulating the nonsarcomeric cytoskeleton. Moreover, the autophagy marker microtubule-associated proteins 1A-1B light chain 3B was increased in the double ROCK knockout, and these early molecular features persisted throughout aging. Mechanistically, the double ROCK knockout promoted age-associated or starvation-induced autophagy concomitant with reduced protein kinase B (AKT), mammalian target of rapamycin (mTOR), Unc-51-like kinase signaling, and cardiac fibrosis. In contrast, ROCK2 knockout hearts showed increased phosphorylated (p)-MLC and p-FAK levels, which were mostly attributable to a compensatory ROCK1 overactivation. Autophagy was inhibited at the baseline accompanying increased mTOR activity, leading to increased cardiac fibrosis in the ROCK2 knockout hearts. Finally, the loss of ROCK1 had no significant effect on p-MLC and p-FAK levels, mTOR signaling, or autophagy at baseline. In summary, deletions of ROCK isoforms in cardiomyocytes have different, even opposite, effects on endogenous ROCK activity and the MLC/FAK/AKT/mTOR signaling pathway, which is involved in autophagy and fibrosis of the heart.-Shi, J., Surma, M., Yang, Y., Wei, L. Disruption of both ROCK1 and ROCK2 genes in cardiomyocytes promotes autophagy and reduces cardiac fibrosis during aging.


Assuntos
Envelhecimento/patologia , Autofagia/fisiologia , Miócitos Cardíacos/metabolismo , Quinases Associadas a rho/fisiologia , Envelhecimento/genética , Envelhecimento/metabolismo , Animais , Autofagia/genética , Cruzamentos Genéticos , Indução Enzimática/efeitos dos fármacos , Feminino , Fibrose , Regulação da Expressão Gênica , Masculino , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Miócitos Cardíacos/patologia , Proteínas Recombinantes/biossíntese , Serina-Treonina Quinases TOR/fisiologia , Tamoxifeno/farmacologia , Quinases Associadas a rho/deficiência , Quinases Associadas a rho/genética
5.
Adv Mater ; 30(30): e1802156, 2018 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-29900596

RESUMO

Lithium (Li) metal anodes have attracted much interest recently for high-energy battery applications. However, low coulombic efficiency, infinite volume change, and severe dendrite formation limit their reliable implementation over a wide range. Here, an outstanding stability for a Li metal anode is revealed by designing a highly porous and hollow Li foam. This unique structure is capable of tackling many Li metal problems simultaneously: first, it assures uniform electrolyte distribution over the inner and outer electrode's surface; second, it reduces the local current density by providing a larger electroactive surface area; third, it can accommodate volume expansion and dissipate heat efficiently. Moreover, the structure shows superior stability compared to fully Li covered foam with low porosity, and bulky Li foil electrode counterparts. This Li foam exhibits small overpotential (≈25 mV at 4 mA cm-2 ) and high cycling stability for 160 cycles at 4 mA cm-2 . Furthermore, when assembled, the porous Li metal as the anode with LiFePO4 as the cathode for a full cell, the battery has a high-rate performance of 138 mAh g-1 at 0.2 C. The beneficial structure of the Li hollow foam is further studied through density functional theory simulations, which confirms that the porous structure has better charge mobility and more uniform Li deposition.

6.
J Am Chem Soc ; 140(29): 9127-9131, 2018 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-29956544

RESUMO

Two-dimensional (2D) materials have attracted great interest in catalyzing electrochemical reactions such as water splitting, oxygen reduction, and carbon dioxide reduction. Quantum mechanical simulations have been extensively employed to study the catalytic mechanisms. These calculations typically assume that the catalyst is charge neutral for computational simplicity; however, in reality, the catalyst is usually charged to match its Fermi level with the applied electrode potential. These contradictions urge an evaluation of the charge effects. Here, using the example of hydrogen adsorption on the common 2D electrocatalysts (N-doped graphene and MoS2) and 3D metal catalysts, and employing the grand canonical density functional theory, we show that the charge on 2D materials can have a much stronger impact on the electrochemical reaction than the charge on 3D metals (the reaction energy can differ by >1 eV after including the charge effects). This arises from the charge-induced change in the occupation of electronic states, which is more significant for 2D materials due to their limited density of states. Our work provides a fundamental understanding of the charge effects in 2D materials, calls for re-evaluation of the previously suggested mechanisms by including the overlooked charge effects, and offers practical guidelines for designing 2D catalysts.

7.
Nat Commun ; 9(1): 1809, 2018 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-29728558

RESUMO

Developing cost-effective electrocatalysts operated in the same electrolyte for water splitting, including oxygen and hydrogen evolution reactions, is important for clean energy technology and devices. Defects in electrocatalysts strongly influence their chemical properties and electronic structures, and can dramatically improve electrocatalytic performance. However, the development of defect-activated electrocatalyst with an efficient and stable water electrolysis activity in alkaline medium remains a challenge, and the understanding of catalytic origin is still limited. Here, we highlight defect-enriched bifunctional eletrocatalyst, namely, three-dimensional iron fluoride-oxide nanoporous films, fabricated by anodization/fluorination process. The heterogeneous films with high electrical conductivity possess embedded disorder phases in crystalline lattices, and contain numerous scattered defects, including interphase boundaries, stacking faults, oxygen vacancies, and dislocations on the surfaces/interface. The heterocatalysts efficiently catalyze water splitting in basic electrolyte with remarkable stability. Experimental studies and first-principle calculations suggest that the surface/edge defects contribute significantly to their high performance.

8.
Oncotarget ; 9(16): 12995-13008, 2018 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-29560126

RESUMO

Doxorubicin is among the essential medicines with a wide antitumor spectrum, but its clinical application is limited by its cardiotoxicity. We recently discovered that ROCK1 is a key molecule in mediating cardiac remodeling in response to various stresses. To determine the roles of ROCK1 in doxorubicin cardiotoxicity, we gave three doses of doxorubicin injections to wild type (WT) and ROCK1-/- mice with one week intervals between treatments, the cumulative dose being 24 mg/kg. ROCK1-/- mice exhibited preserved cardiac function, reduced apoptosis, autophagy and fibrosis compared to the WT mice. To further determine the cellular mechanisms, we have examined the role of ROCK1 in cardiomyocytes using cardiomyocyte-specific knockout mice, MHC-Cre/ROCK1fl/fl, which partially reproduced the cardioprotective characteristics of ROCK1-/- mice, indicating that ROCK1 in both cardiomyocytes and non-cardiomyocytes mediates doxorubicin cardiotoxicity. To elucidate the molecular mechanisms, a detailed time course study after a single doxorubicin injection at 10 mg/kg was performed in ROCK1-/- and MHC-Cre/ROCK1fl/fl mice. The molecular analysis revealed that both ROCK1-/- and MHC-Cre/ROCK1fl/fl hearts exhibited significant reduction of doxorubicin-induced early responses including increased apoptotic (Bax) and autophagic (p62/SQSTM1 and LC3-II) markers, associated with reduced Beclin 1 phosphorylation on Thr119, supporting reduced Beclin 1-mediated autophagy initiation due to increased association of Beclin 1 with Bcl 2 or Bcl-XL in these hearts compared to the WT or ROCK1fl/fl mice. These results support that ROCK1 deficiency is cardioprotective against doxorubicin-induced cardiotoxicity at least in part through reducing Beclin 1-mediated autophagy initiation in cardiomyocytes and restoring autophagic flux to ameliorate doxorubicin cardiotoxicity.

9.
Oncotarget ; 7(13): 16936-47, 2016 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-26943578

RESUMO

Understanding mast cell development is essential due to their critical role in regulating immunity and autoimmune diseases. Here, we show how Rho kinases (ROCK) regulate mast cell development and can function as therapeutic targets for treating allergic diseases. Rock1 deficiency results in delayed maturation of bone marrow derived mast cells (BMMCs) in response to IL-3 stimulation and reduced growth in response to stem cell factor (SCF) stimulation. Further, integrin-mediated adhesion and migration, and IgE-mediated degranulation are all impaired in Rock1-deficient BMMCs. To understand the mechanism behind altered mast cell development in Rock1-/- BMMCs, we analyzed the activation of ROCK and its downstream targets including LIM kinase (LIMK). We observed reduced activation of ROCK, LIMK, AKT and ERK1/2 in Rock1-deficient BMMCs in response to SCF stimulation. Further, loss of either Limk1 or Limk2 also demonstrated altered BMMC maturation and growth; combined deletion of both Limk1 and Limk2 resulted in further reduction in BMMC maturation and growth. In passive cutaneous anaphylaxis model, deficiency of Rock1 or treatment with ROCK inhibitor Fasudil protected mice against IgE-mediated challenge. Our results identify ROCK/LIMK pathway as a novel therapeutic target for treating allergic diseases involving mast cells.


Assuntos
Diferenciação Celular/imunologia , Quinases Lim/metabolismo , Mastócitos/citologia , Mastócitos/metabolismo , Quinases Associadas a rho/metabolismo , Actinas/metabolismo , Animais , Adesão Celular/imunologia , Degranulação Celular/imunologia , Movimento Celular/imunologia , Hipersensibilidade/imunologia , Camundongos , Camundongos Knockout
10.
Hypertension ; 67(3): 597-605, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26781283

RESUMO

The insufficiency of compensatory angiogenesis in the heart of patients with hypertension contributes to heart failure transition. The hypoxia-inducible factor 1α-vascular endothelial growth factor (HIF1α-VEGF) signaling cascade controls responsive angiogenesis. One of the challenges in reprograming the insufficient angiogenesis is to achieve a sustainable tissue exposure to the proangiogenic factors, such as HIF1α stabilization. In this study, we identified Rnd3, a small Rho GTPase, as a proangiogenic factor participating in the regulation of the HIF1α-VEGF signaling cascade. Rnd3 physically interacted with and stabilized HIF1α, and consequently promoted VEGFA expression and endothelial cell tube formation. To demonstrate this proangiogenic role of Rnd3 in vivo, we generated Rnd3 knockout mice. Rnd3 haploinsufficient (Rnd3(+/-)) mice were viable, yet developed dilated cardiomyopathy with heart failure after transverse aortic constriction stress. The poststress Rnd3(+/-) hearts showed significantly impaired angiogenesis and decreased HIF1α and VEGFA expression. The angiogenesis defect and heart failure phenotype were partially rescued by cobalt chloride treatment, a HIF1α stabilizer, confirming a critical role of Rnd3 in stress-responsive angiogenesis. Furthermore, we generated Rnd3 transgenic mice and demonstrated that Rnd3 overexpression in heart had a cardioprotective effect through reserved cardiac function and preserved responsive angiogenesis after pressure overload. Finally, we assessed the expression levels of Rnd3 in the human heart and detected significant downregulation of Rnd3 in patients with end-stage heart failure. We concluded that Rnd3 acted as a novel proangiogenic factor involved in cardiac responsive angiogenesis through HIF1α-VEGFA signaling promotion. Rnd3 downregulation observed in patients with heart failure may explain the insufficient compensatory angiogenesis involved in the transition to heart failure.


Assuntos
Vasos Coronários/patologia , Regulação da Expressão Gênica , Hipertensão/genética , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Neovascularização Patológica/genética , Fator A de Crescimento do Endotélio Vascular/genética , Proteínas rho de Ligação ao GTP/genética , Animais , Western Blotting , Vasos Coronários/metabolismo , Modelos Animais de Doenças , Endotélio Vascular/metabolismo , Endotélio Vascular/patologia , Humanos , Hipertensão/metabolismo , Hipertensão/patologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/biossíntese , Camundongos , Camundongos Knockout , Camundongos Transgênicos , Neovascularização Patológica/metabolismo , RNA/genética , Transdução de Sinais , Fator A de Crescimento do Endotélio Vascular/biossíntese , Proteínas rho de Ligação ao GTP/biossíntese
11.
Arch Immunol Ther Exp (Warsz) ; 64(4): 259-78, 2016 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-26725045

RESUMO

Rho-associated coiled-coil kinase (ROCK) is a major downstream effector of the small GTPase RhoA. The ROCK family, consisting of ROCK1 and ROCK2, plays a central role in the organization of the actin cytoskeleton, and is involved in a wide range of fundamental cellular functions such as contraction, adhesion, migration, proliferation, and apoptosis. Since the discovery of effective inhibitors such as fasudil and Y27632, the biological roles of ROCK have been extensively explored in numerous diseases, including cancer. Accumulating evidence supports the concept that ROCK plays important roles in tumor development and progression through regulating many key cellular functions associated with malignancy, including tumorigenicity, tumor growth, metastasis, angiogenesis, tumor cell apoptosis/survival and chemoresistance as well. This review focuses on the new advances of the most recent 5 years from the studies on the roles of ROCK in cancer development and progression; the discussion is mainly focused on the potential value of ROCK inhibitors in cancer therapy.


Assuntos
Neoplasias/metabolismo , Quinases Associadas a rho/metabolismo , Apoptose , Adesão Celular , Movimento Celular , Proliferação de Células , Sobrevivência Celular , Progressão da Doença , Resistencia a Medicamentos Antineoplásicos , Humanos , MicroRNAs/metabolismo , Mutação , Metástase Neoplásica , Neoplasias/genética , Células-Tronco Neoplásicas/citologia , Neovascularização Patológica , Polimorfismo Genético , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Transdução de Sinais , Quinases Associadas a rho/genética
12.
J BUON ; 20(5): 1223-8, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26537068

RESUMO

PURPOSE: Prostate cancer (PCa) is one of the most common malignancies in males, and multiple genetic studies have confirmed association with susceptibility to PCa. However, the risk conferred in men living in China is unkown. We selected 6 previously identified variants as candidates to define their association with PCa in Chinese men. METHODS: We genotyped 6 single nucleotide polymorphisms (SNPs) (rs1465618, rs1983891, rs339331, rs16901966, rs1447295 and rs10090154) using high resolution melting (HRM) analysis and assessed their association with PCa risk in a case-control study of 481 patients and 480 controls in a Chinese population. In addition, the individual and cumulative contribution for the risk of PCa and clinical covariates were analysed. RESULTS: We found that 5 of the 6 genetic variants were associated with PCa risk. The T allele of rs339331 and the G allele of rs16901966 showed a significant association with PCa susceptibility: OR (95%CI)= 0.78 (0.64-0.94), p<0.009 and OR (95%CI)= 0.66 (0.54-0.81), p<0.0001, as well as A allele of rs1447295 (OR [95%CI]=1.46 (1.17-1.84), p<0.001) and T allele of rs10090154 (OR [95%CI]= 0.58 (0.46-0.74), p<0.0001). rs339331(T) was associated with a 0.71-fold and 1.42-fold increase of PCa risk by dominant model (p=0.007) and recessive model (p=0.007). rs16901966 (G) was associated with a 0.51-fold and 1.98-fold increase of PCa risk by dominant model (p=0.006) and recessive model (p=0.0058). rs10090154 (T) was associated with a 1.89-fold and 0.53-fold increase of PCa risk by dominant model (p=0.000006) and recessive model (p=0.000006). And, rs1983891(C) was associated with a 0.77-fold increase of PCa risk by recessive model (p=0.045). rs1447295 was associated with a 1.57-fold increase of PCa risk by dominant model (p=0.008). rs1465618 showed no significant association with PCa. The cumulative effects test of risk alleles (rs rs1983891, rs339331, rs16901966, rs1447295 and rs10090154) showed an increasing risk to PCa in a frequency-dependent manner (ptrend=0.001), and men with more than 3 risk alleles had the most significant susceptibility to PCa (OR=1.99, p=0.001), compared with those who had one risk allele (OR=1.17, p=0.486). CONCLUSION: Our results provide further support for association of the THADA, FOXP4, GPRC6A/RFX6 and 8q24 genes with Pca in Asian populations. Further work is still required to determine the functional variations and finally clarify the underlying biological mechanisms.


Assuntos
Proteínas de Ligação a DNA/genética , Fatores de Transcrição Forkhead/genética , Predisposição Genética para Doença , Proteínas de Neoplasias/genética , Polimorfismo de Nucleotídeo Único , Neoplasias da Próstata/genética , Receptores Acoplados a Proteínas-G/genética , Fatores de Transcrição/genética , Adulto , Idoso , Alelos , Cromossomos Humanos Par 8 , Humanos , Masculino , Pessoa de Meia-Idade , Neoplasias da Próstata/etiologia , Neoplasias da Próstata/patologia , Fatores de Transcrição de Fator Regulador X , Risco
13.
PLoS One ; 10(7): e0131763, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26134406

RESUMO

We have recently reported that ROCK1 deficiency in mouse embryonic fibroblasts (MEF) has superior anti-apoptotic and pro-survival effects than antioxidants against doxorubicin, a chemotherapeutic drug. Although oxidative stress is the most widely accepted mechanism, our studies suggest that ROCK1-dependent actin cytoskeleton remodeling plays a more important role in mediating doxorubicin cytotoxicity on MEFs. To further explore the contributions of ROCK1-dependent actin cytoskeleton remodeling in response to stress, this study investigates the mechanistic differences between the cytotoxic effects of doxorubicin versus hydrogen peroxide (H2O2), with a focus on cytoskeleton alterations, apoptosis and necrosis induction. We found that both types of stress induce caspase activation but with different temporal patterns and magnitudes in MEFs: H2O2 induces the maximal levels (2 to 4-fold) of activation of caspases 3, 8, and 9 within 4 h, while doxorubicin induces much higher maximal levels (15 to 25-fold) of caspases activation at later time points (16-24 h). In addition, necrosis induced by H2O2 reaches maximal levels within 4 h while doxorubicin-induced necrosis largely occurs at 16-24 h secondary to apoptosis. Moreover, both types of stress induce actin cytoskeleton remodeling but with different characteristics: H2O2 induces disruption of stress fibers associated with cytosolic translocation of phosphorylated myosin light chain (p-MLC) from stress fibers, while doxorubicin induces cortical F-actin formation associated with cortical translocation of p-MLC from central stress fibers. Furthermore, N-acetylcysteine (an antioxidant) is a potent suppressor for H2O2-induced cytotoxic effects including caspase activation, necrosis, and cell detachment, but shows a much reduced inhibition on doxorubicin-induced changes. On the other hand, ROCK1 deficiency is a more potent suppressor for the cytotoxic effects induced by doxorubicin than by H2O2. These results support the notion that doxorubicin induces caspase activation, necrosis, and actin cytoskeleton alterations largely through ROCK1-dependent and oxidative stress-independent pathways.


Assuntos
Citoesqueleto de Actina/metabolismo , Doxorrubicina/química , Estresse Oxidativo , Quinases Associadas a rho/metabolismo , Actinas/metabolismo , Animais , Antibióticos Antineoplásicos/química , Antioxidantes/metabolismo , Apoptose , Caspase 3/metabolismo , Caspase 8/metabolismo , Caspase 9/metabolismo , Sobrevivência Celular , Ativação Enzimática , Fibroblastos/metabolismo , Peróxido de Hidrogênio/química , Camundongos , Microscopia de Fluorescência , Necrose , Fosforilação , Fibras de Estresse/patologia
14.
ACS Appl Mater Interfaces ; 6(9): 6786-9, 2014 May 14.
Artigo em Inglês | MEDLINE | ID: mdl-24694204

RESUMO

Using first-principles calculation based on density functional theory, diffusion of Mg atom into α- and ß-Sn was investigated. The diffusion barriers are 0.395 and 0.435 eV for an isolated Mg atom in the α- and ß-Sn, respectively. However, the diffusion barriers of the Mg atom decrease in the α-Sn, whereas they increase in the ß-Sn, when an additional Mg atom was inserted near the original diffusing Mg atom, which is mainly due to strong binding of Mg-Mg atoms in the ß-Sn. Therefore, it is better to use the α-Sn, rather than the ß-Sn, as an anode material for Mg ion batteries.

15.
PLoS One ; 9(3): e90758, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24595357

RESUMO

We have recently reported that the homologous Rho kinases, ROCK1 and ROCK2, play different roles in regulating stress-induced stress fiber disassembly and cell detachment, and the ROCK1 deficiency in mouse embryonic fibroblasts (MEF) has remarkable anti-apoptotic, anti-detachment and pro-survival effects against doxorubicin, a chemotherapeutic drug. This study investigated the roles of ROCK isoforms in doxorubicin-induced reactive oxygen species (ROS) generation which is believed to be the major mechanism underlying its cytotoxicity to normal cells, and especially to cardiomyocytes. Different antioxidants have been shown to provide a protective role reported in numerous experimental studies, but clinical trials of antioxidant therapy showed insufficient benefit against the cardiac side effect. We found that both ROCK1-/- and ROCK2-/- MEFs exhibited reduced ROS production in response to doxorubicin treatment. Interestingly, only ROCK1 deficiency, but not ROCK2 deficiency, significantly enhanced the protective effects of antioxidants against doxorubicin-induced cytotoxicity. First, ROCK1 deficiency and N-acetylcysteine (an anti-oxidant) treatment synergistically reduced ROS levels, caspase activation and cell detachment. In addition, the reduction of ROS generation in ROCK1-/- MEFs in response to doxorubicin treatment was in part through inhibiting NADPH oxidase activity. Furthermore, ROCK1 deficiency enhanced the inhibitory effects of diphenyleneiodonium (an inhibitor of NADPH oxidase) on ROS generation and caspase 3 activation induced by doxorubicin. Finally, ROCK1 deficiency had greater protective effects than antioxidant treatment, especially on reducing actin cytoskeleton remodeling. ROCK1 deficiency not only reduced actomyosin contraction but also preserved central stress fiber stability, whereas antioxidant treatment only reduced actomyosin contraction without preserving central stress fibers. These results reveal a novel strategy to enhance the protective effect of antioxidant therapy by targeting the ROCK1 pathway to stabilize the actin cytoskeleton and boost the inhibitory effects on ROS production, apoptosis and cell detachment.


Assuntos
Antibióticos Antineoplásicos/efeitos adversos , Antioxidantes/farmacologia , Apoptose/efeitos dos fármacos , Doxorrubicina/efeitos adversos , Fibroblastos/efeitos dos fármacos , Deleção de Genes , Quinases Associadas a rho/genética , Animais , Células Cultivadas , Ativação Enzimática/efeitos dos fármacos , Fibroblastos/citologia , Fibroblastos/metabolismo , Camundongos , NADPH Oxidases/metabolismo , Espécies Reativas de Oxigênio/metabolismo
16.
Am J Physiol Endocrinol Metab ; 306(3): E332-43, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24326423

RESUMO

Rho kinase (ROCK) isoforms regulate insulin signaling and glucose metabolism negatively or positively in cultured cell lines and skeletal muscle. However, the in vivo function of the ROCK1 isoform in adipose tissue has not been addressed. To determine the specific role of the adipose ROCK1 isoform in the development of insulin resistance and obesity, mice lacking ROCK1 in adipose tissue globally or selectively were studied. Here, we show that insulin's ability to activate IRS-1/PI3K/Akt signaling was greatly enhanced in adipose tissue of ROCK1(-/-) mice compared with wild-type mice. These effects resulted from the inhibitory effect of ROCK1 on insulin receptor action, as evidenced by the fact that IR tyrosine phosphorylation was abolished in ROCK1(-/-) MEF cells when ROCK1 was reexpressed. Consistently, adipose-specific disruption of ROCK1 increased IR tyrosine phosphorylation in adipose tissue and modestly improved sensitivity to insulin in obese mice induced by high-fat feeding. This effect is independent of any changes in adiposity, number or size of adipocytes, and metabolic parameters, including glucose, insulin, leptin, and triglyceride levels, demonstrating a minimal effect of adipose ROCK1 on whole body metabolism. Enzymatic activity of ROCK1 in adipose tissue remained ∼50%, which likely originated from the fraction of stromal vascular cells, suggesting involvement of these cells for adipose metabolic regulation. Moreover, ROCK isoform activities were increased in adipose tissue of diet-induced or genetically obese mice. These data suggest that adipose ROCK1 isoform plays an inhibtory role for the regulation of insulin sensitivity in diet-induced obesity in vivo.


Assuntos
Dieta/efeitos adversos , Deleção de Genes , Resistência à Insulina/genética , Quinases Associadas a rho/genética , Tecido Adiposo/metabolismo , Animais , Células Cultivadas , Feminino , Isoenzimas/genética , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/genética , Obesidade/metabolismo , Especificidade de Órgãos/genética
17.
J Cardiovasc Pharmacol ; 62(4): 341-54, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23921309

RESUMO

Rho kinase (ROCK) is a major downstream effector of the small GTPase RhoA. ROCK family, consisting of ROCK1 and ROCK2, plays central roles in the organization of actin cytoskeleton and is involved in a wide range of fundamental cellular functions, such as contraction, adhesion, migration, proliferation, and apoptosis. Due to the discovery of effective inhibitors, such as fasudil and Y27632, the biological roles of ROCK have been extensively explored with particular attention on the cardiovascular system. In many preclinical models of cardiovascular diseases, including vasospasm, arteriosclerosis, hypertension, pulmonary hypertension, stroke, ischemia-reperfusion injury, and heart failure, ROCK inhibitors have shown a remarkable efficacy in reducing vascular smooth muscle cell hypercontraction, endothelial dysfunction, inflammatory cell recruitment, vascular remodeling, and cardiac remodeling. Moreover, fasudil has been used in the clinical trials of several cardiovascular diseases. The continuing utilization of available pharmacological inhibitors and the development of more potent or isoform-selective inhibitors in ROCK signaling research and in treating human diseases are escalating. In this review, we discuss the recent molecular, cellular, animal, and clinical studies with a focus on the current understanding of ROCK signaling in cardiovascular physiology and diseases. We particularly note that emerging evidence suggests that selective targeting ROCK isoform based on the disease pathophysiology may represent a novel therapeutic approach for the disease treatment including cardiovascular diseases.


Assuntos
1-(5-Isoquinolinasulfonil)-2-Metilpiperazina/análogos & derivados , Doenças Cardiovasculares/tratamento farmacológico , Quinases Associadas a rho/metabolismo , 1-(5-Isoquinolinasulfonil)-2-Metilpiperazina/farmacologia , Amidas/farmacologia , Animais , Doenças Cardiovasculares/fisiopatologia , Fenômenos Fisiológicos Cardiovasculares , Desenho de Fármacos , Humanos , Terapia de Alvo Molecular , Inibidores de Proteínas Quinases/farmacologia , Piridinas/farmacologia , Transdução de Sinais/fisiologia
18.
Analyst ; 138(18): 5274-80, 2013 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-23865087

RESUMO

A multi-responsive sensor 1 was constructed by combining a ferrocene unit and a rhodamine block via a carbohydrazone bond. The sensor showed high selectivity toward Cu(2+) over other common metal ions in a wide pH range with excellent reversibility and rapid response. The obvious color change from colorless to pink upon the addition of Cu(2+) could make it a suitable 'naked-eye' indicator for Cu(2+). The detection limit (LOD) obtained was down to 2.0 nM and the association constant (Ka) was evaluated as 4.65 × 10(7) M(-1). The accuracy for detecting Cu(2+) in environmental river water was compared favorably with the traditional atomic absorption spectroscopy method (AAS). Finally, we proposed a reversible ring-opening mechanism (Off-On) of the rhodamine spirolactam induced by Cu(2+) binding and a 2 : 1 stoichiometric structure between 1 and Cu(2+).


Assuntos
Técnicas de Química Analítica/instrumentação , Cobre/análise , Colorimetria , Cobre/química , Eletroquímica , Concentração de Íons de Hidrogênio , Espectrometria de Fluorescência , Fatores de Tempo , Água/química
19.
Cell Cycle ; 12(10): 1492-500, 2013 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-23598717

RESUMO

The homologous Rho kinases, ROCK1 and ROCK2, are involved in stress fiber assembly and cell adhesion and are assumed to be functionally redundant. Using mouse embryonic fibroblasts (MEFs) derived from ROCK1(-/-) and ROCK2(-/-) mice, we have recently reported that they play different roles in regulating doxorubicin-induced stress fiber disassembly and cell detachment: ROCK1 is involved in destabilizing the actin cytoskeleton and cell detachment, whereas ROCK2 is required for stabilizing the actin cytoskeleton and cell adhesion. Here, we present additional insights into the roles of ROCK1 and ROCK2 in regulating stress-induced impairment of cell-matrix and cell-cell adhesion. In response to doxorubicin, ROCK1(-/-) MEFs showed significant preservation of both focal adhesions and adherens junctions, while ROCK2(-/-) MEFs exhibited impaired focal adhesions but preserved adherens junctions compared with the wild-type MEFs. Additionally, inhibition of focal adhesion or adherens junction formations by chemical inhibitors abolished the anti-detachment effects of ROCK1 deletion. Finally, ROCK1(-/-) MEFs, but not ROCK2(-/-) MEFs, also exhibited preserved central stress fibers and reduced cell detachment in response to serum starvation. These results add new insights into a novel mechanism underlying the anti-detachment effects of ROCK1 deletion mediated by reduced peripheral actomyosin contraction and increased actin stabilization to promote cell-cell and cell-matrix adhesion. Our studies further support the differential roles of ROCK isoforms in regulating stress-induced loss of central stress fibers and focal adhesions as well as cell detachment.


Assuntos
Quinases Associadas a rho/metabolismo , Citoesqueleto de Actina/efeitos dos fármacos , Junções Aderentes/efeitos dos fármacos , Animais , Antibióticos Antineoplásicos/farmacologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Cofilina 1/metabolismo , Doxorrubicina/farmacologia , Ácido Egtázico/farmacologia , Adesões Focais/efeitos dos fármacos , Proteínas de Membrana/metabolismo , Camundongos , Camundongos Knockout , Fosforilação , Fibras de Estresse/efeitos dos fármacos , Quinases Associadas a rho/deficiência , Quinases Associadas a rho/genética
20.
Cell Death Dis ; 4: e483, 2013 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-23392171

RESUMO

This study, using mouse embryonic fibroblast (MEF) cells derived from ROCK1(-/-) and ROCK2(-/-) mice, is designed to dissect roles for ROCK1 and ROCK2 in regulating actin cytoskeleton reorganization induced by doxorubicin, a chemotherapeutic drug. ROCK1(-/-) MEFs exhibited improved actin cytoskeleton stability characterized by attenuated periphery actomyosin ring formation and preserved central stress fibers, associated with decreased myosin light chain 2 (MLC2) phosphorylation but preserved cofilin phosphorylation. These effects resulted in a significant reduction in cell shrinkage, detachment, and predetachment apoptosis. In contrast, ROCK2(-/-) MEFs showed increased periphery membrane folding and impaired cell adhesion, associated with reduced phosphorylation of both MLC2 and cofilin. Treatment with inhibitor of myosin (blebbistatin), inhibitor of actin polymerization (cytochalasin D), and ROCK pan-inhibitor (Y27632) confirmed the contributions of actomyosin contraction and stress fiber instability to stress-induced actin cytoskeleton reorganization. These results support a novel concept that ROCK1 is involved in destabilizing actin cytoskeleton through regulating MLC2 phosphorylation and peripheral actomyosin contraction, whereas ROCK2 is required for stabilizing actin cytoskeleton through regulating cofilin phosphorylation. Consequently, ROCK1 and ROCK2 can be functional different in regulating stress-induced stress fiber disassembly and cell detachment.


Assuntos
Quinases Associadas a rho/metabolismo , Citoesqueleto de Actina/efeitos dos fármacos , Actinas/metabolismo , Amidas/farmacologia , Animais , Antibióticos Antineoplásicos/farmacologia , Miosinas Cardíacas/metabolismo , Caspases/metabolismo , Linhagem Celular , Forma Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Cofilina 1/metabolismo , Citocalasina D/farmacologia , Doxorrubicina/farmacologia , Camundongos , Camundongos Knockout , Cadeias Leves de Miosina/metabolismo , Fosforilação , Piridinas/farmacologia , Quinases Associadas a rho/deficiência , Quinases Associadas a rho/genética
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