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1.
J Mech Behav Biomed Mater ; 102: 103490, 2019 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-31877512

RESUMO

Mechanical failure of zirconia-based full-arch implant-supported fixed dental prostheses (FAFDPs) remains a critical issue in prosthetic dentistry. The option of full-arch implant treatment and the biomechanical behaviour within a sophisticated screw-retained prosthetic structure have stimulated considerable interest in fundamental and clinical research. This study aimed to analyse the biomechanical responses of zirconia-based FAFDPs with different implant configurations (numbers and distributions), thereby predicting the possible failure sites and the optimum configuration from biomechanical aspect by using finite element method (FEM). Five 3D finite element (FE) models were constructed with patient-specific heterogeneous material properties of mandibular bone. The results were reported using volume-averaged von-Mises stresses (σVMVA) to eliminate numerical singularities. It was found that wider placement of multi-unit copings was preferred as it reduces the cantilever effect on denture. Within the limited areas of implant insertion, the adoption of angled multi-unit abutments allowed the insertion of oblique implants in the bone and wider distribution of the multi-unit copings in the prosthesis, leading to lower stress concentration on both mandibular bone and prosthetic components. Increasing the number of supporting implants in a FAFDPs reduced loading on each implant, although it may not necessarily reduce the stress concentration in the most posterior locations significantly. Overall, the 6-implant configuration was a preferable configuration as it provided the most balanced mechanical performance in this patient-specific case.

2.
JCI Insight ; 4(21)2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31672934

RESUMO

Neutrophils play critical roles during the initial phase of hepatic ischemia/reperfusion injury (HIRI). However, the regulation of neutrophil activation, infiltration, and proinflammatory cytokine secretion has not been fully elucidated. In this study, we revealed that OX40 was expressed by neutrophils, its expression in neutrophils was time-dependently upregulated following HIRI, and Ox40 knockout markedly alleviated liver injury. Compared with wild-type neutrophils, the adoptive transfer of Ox40-/- neutrophils decreased HIRI in neutrophil-depleted Rag2/Il2rg-/- or Ox40-/- mice. Moreover, consistently, the in vitro experiments showed that Ox40 not only prolonged neutrophil survival but also promoted proinflammatory cytokines, ROS production, and even neutrophil chemotaxis. Further investigation demonstrated that the knockout of Ox40 in neutrophils inhibited NF-κB signaling via the TRAF1/2/4 and IKKα/IKKß/IκBα pathways. OX40L and OX86 stimulation could enhance neutrophil activation and survival in vitro and in vivo. In conclusion, our study provides a new understanding of OX40, which is expressed not only in adaptive immune cells but also in innate immune cells, i.e., neutrophils, contributing to the activation and survival of neutrophils. These findings provide a novel potential therapeutic target for the prevention of HIRI during liver transplantation or hepatic surgery.

3.
Nat Commun ; 10(1): 4246, 2019 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-31534137

RESUMO

Allergic asthma is an inflammatory disorder of the airway without satisfactory traditional therapies capable of controlling the underlying pathology. New approaches that can overcome the detrimental effects of immune dysregulation are thus desirable. Here we adoptively transfer ovalbumin (OVA) peptide-primed CD4-CD8- double negative T (DNT) cells intravenously into a mouse model of OVA-induced allergic asthma to find that OVA-induced airway hyperresponsiveness, lung inflammation, mucus production and OVA-specific IgG/IgE production are significantly suppressed. The immunosuppressive function of the OVA-specific DNT cells is dependent on the inhibition of CD11b+ dendritic cell function, T follicular helper cell proliferation, and IL-21 production. Mechanistically, Lag3 contributes to MHC-II antigen recognition and trogocytosis, thereby modulating the antigen-specific immune regulation by DNT cells. The effectiveness of ex vivo-generated allergen-specific DNT cells in alleviating airway inflammation thus supports the potential utilization of DNT cell-based therapy for the treatment of allergic asthma.

4.
FASEB J ; 33(7): 8490-8503, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30951375

RESUMO

The liver is a central immunologic organ with a high density of myeloid and lymphoid immune cells that play important roles in the development and progression of nonalcoholic steatohepatitis (NASH). However, the immune-cell-mediated regulation of NASH and its underlying mechanisms remain obscure. In this study, Prf1null mice showed significantly higher plasma alanine transaminase levels, with increased liver fat accumulation, lobular inflammation, and focal necrosis compared with wild-type (WT) mice after 4 wk of feeding on a methionine- and choline-deficient diet (MCD) or 16 wk of feeding on a high-fat diet. Perforin deficiency promoted the M1 polarization of infiltrated monocytes. Moreover, MCD-fed Prf1null mice exhibited increased accumulation, survival, activation, and proinflammatory cytokine production of CD8 T cells but not NK cells or CD4 T cells. Adoptive transfer of CD8 T cells or NK cells from WT or Prf1null mice, together with non-CD8 cells or non-NK cells from WT mice, indicated that CD8 T-cell-derived perforin participates in the mechanism regulating liver inflammation and thus plays a protective role in the development of NASH. Perforin-deficient CD8 T cells exhibited decreased cytotoxicity toward bone marrow-derived M1 monocytes and macrophages. According to the RNA sequencing data, the perforin deficiency inhibited cell apoptosis and enhanced the activation, migration, and proinflammatory cytokine production of CD8 T cells in mice with NASH. Furthermore, we found higher plasma soluble perforin levels and hepatic perforin expression in NASH patients, suggesting clinical relevance of the findings. We have elucidated an important role for the cytotoxic immune effector molecule perforin from CD8 T cells in restricting hepatic inflammation in mice with NASH and suggest that therapies designed to maximize the function of endogenous perforin in CD8 T cells might have potential benefits as NASH treatments.-Wang, T., Sun, G., Wang, Y., Li, S., Zhao, X., Zhang, C., Jin, H., Tian, D., Liu, K., Shi, W., Tian, Y., Zhang, D. The immunoregulatory effects of CD8 T-cell-derived perforin on diet-induced nonalcoholic steatohepatitis.

5.
J Mech Behav Biomed Mater ; 89: 150-161, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30286374

RESUMO

OBJECTIVES: This study aimed to develop a simple and efficient numerical modeling approach for characterizing strain and total strain energy in bone scaffolds implanted in patient-specific anatomical sites. MATERIALS AND METHODS: A simplified homogenization technique was developed to substitute a detailed scaffold model with the same size and equivalent orthotropic material properties. The effectiveness of the proposed modeling approach was compared with two other common homogenization methods based on periodic boundary conditions and the Hills-energy theorem. Moreover, experimental digital image correlation (DIC) measurements of full-field surface strain were conducted to validate the numerical results. RESULTS: The newly proposed simplified homogenization approach allowed for fairly accurate prediction of strain and total strain energy in tissue scaffolds implanted in a large femur mid-shaft bone defect subjected to a simulated in-vivo loading condition. The maximum discrepancy between the total strain energy obtained from the simplified homogenization approach and the one obtained from detailed porous scaffolds was 8.8%. Moreover, the proposed modeling technique could significantly reduce the computational cost (by about 300 times) required for simulating an in-vivo bone scaffolding scenario as the required degrees of freedom (DoF) was reduced from about 26 million for a detailed porous scaffold to only 90,000 for the homogenized solid counterpart in the analysis. CONCLUSIONS: The simplified homogenization approach has been validated by correlation with the experimental DIC measurements. It is fairly efficient and comparable with some other common homogenization techniques in terms of accuracy. The proposed method is implicating to different clinical applications, such as the optimal selection of patient-specific fixation plates and screw system.

6.
IEEE Trans Cybern ; 49(5): 1642-1656, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-29993704

RESUMO

For expensive constrained optimization problems (ECOPs), the computation of objective function and constraints is very time-consuming. This paper proposes a novel global and local surrogate-assisted differential evolution (DE) for solving ECOPs with inequality constraints. The proposed method consists of two main phases: 1) global surrogate-assisted phase and 2) local surrogate-assisted phase. In the global surrogate-assisted phase, DE serves as the search engine to produce multiple trial vectors. Afterward, the generalized regression neural network is used to evaluate these trial vectors. In order to select the best candidate from these trial vectors, two rules are combined. The first is the feasibility rule, which at first guides the population toward the feasible region, and then toward the optimal solution. In addition, the second rule puts more emphasis on the solution with the highest predicted uncertainty, and thus alleviates the inaccuracy of the surrogates. In the local surrogate-assisted phase, the interior point method coupled with radial basis function is utilized to refine each individual in the population. During the evolution, the global surrogate-assisted phase has the capability to promptly locate the promising region and the local surrogate-assisted phase is able to speed up the convergence. Therefore, by combining these two important elements, the number of fitness evaluations can be reduced remarkably. The proposed method has been tested on numerous benchmark test functions from three test suites and two real-world cases. The experimental results demonstrate that the performance of the proposed method is better than that of other state-of-the-art methods.

7.
Cell Rep ; 25(13): 3786-3799.e4, 2018 12 26.
Artigo em Inglês | MEDLINE | ID: mdl-30590049

RESUMO

Both innate and adaptive immune cells are involved in the pathogenesis of nonalcoholic steatohepatitis (NASH), but the crosstalk between innate and adaptive immunity is largely unknown. Here we show that compared with WT mice, OX40-/- mice exhibit decreased liver fat accumulation, lobular inflammation, and focal necrosis after feeding with diets that induce NASH. Mechanistically, OX40 deficiency suppresses Th1 and Th17 differentiation, and OX40 deficiency in T cells inhibits monocyte migration, antigen presentation, and M1 polarization. Soluble OX40 stimulation alone upregulates antigen presentation, chemokine receptor expression, and proinflammatory cytokine secretion by liver monocytes. Furthermore, plasma soluble OX40 levels are positively associated with NASH in humans, suggesting clinical relevance of the findings. In conclusion, we show a mechanism for T cell regulation of innate immune cells. OX40 is a key regulator of both intrahepatic innate and adaptive immunity, generates two-way signals, and promotes both proinflammatory monocyte and macrophage and T cell function, resulting in NASH development.


Assuntos
Imunidade Adaptativa , Imunidade Inata , Hepatopatia Gordurosa não Alcoólica/imunologia , Hepatopatia Gordurosa não Alcoólica/patologia , Receptores OX40/metabolismo , Animais , Apresentação do Antígeno , Diferenciação Celular , Sobrevivência Celular , Citocinas/metabolismo , Regulação para Baixo , Humanos , Mediadores da Inflamação/metabolismo , Fígado/imunologia , Fígado/patologia , Ativação Linfocitária/imunologia , Camundongos Endogâmicos C57BL , Monócitos/patologia , Hepatopatia Gordurosa não Alcoólica/sangue , Receptores OX40/sangue , Receptores OX40/deficiência , Solubilidade , Linfócitos T/imunologia
8.
Cell Death Dis ; 9(6): 616, 2018 05 23.
Artigo em Inglês | MEDLINE | ID: mdl-29795285

RESUMO

CD4+ T-cell-converted CD4-CD8- double negative (cDNT) have strong suppressive activity in the maintenance of immune tolerance, whereas IL-2 promotes cDNT proliferation and enhances cDNT resistance to apoptosis. However, the intrinsic mechanisms that regulate the survival of cDNT are still unknown. Here we demonstrate that the OX40 molecule was highly expressed on cDNT. The expression of OX40 was necessary to promote proliferation and inhibit apoptosis of cDNT in vivo and in vitro. OX40 promoted the survival of cDNT by regulating the expression of Bcl-2, Bcl-xL, Survivin, and BCL2L11. Canonical NF-κB cell signaling played an important role in the transmission of essential division and survival signals through OX40 in cDNT. IL-2 promoted the survival of cDNT in part via elevating the expression of the OX40 molecule. IL-2 promoted OX40 expression via downregulating the PPARα expression. In conclusion, we elucidated that OX40 is a key molecule that regulates cDNT proliferation and survival. IL-2 promoted OX40 expression by downregulating the PPARα binding to the OX40 promoter, leading to the elevated expression of Bcl-2, Bcl-xL, and Survivin in cDNT, which finally resulted in the promoted proliferation and decreased apoptosis of cDNT.


Assuntos
Linfócitos T CD4-Positivos/citologia , Linfócitos T CD4-Positivos/metabolismo , Receptores OX40/metabolismo , Animais , Apoptose , Sequência de Bases , Proliferação de Células , Sobrevivência Celular , Regulação da Expressão Gênica , Interleucina-2/metabolismo , Masculino , Camundongos Endogâmicos C57BL , PPAR alfa/metabolismo , Survivina/metabolismo , Proteína bcl-X/metabolismo
9.
Lab Invest ; 98(7): 871-882, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29497174

RESUMO

Hepatocellular carcinoma (HCC) is one of the most lethal malignancies due to its high frequency of metastasis via the epithelial-mesenchymal transition (EMT) pathway. Hepatic stimulator substance (HSS) can protect hepatocytes from injury and promote liver growth. Recent studies indicated that HSS expression is increased in HCC tissues; however, whether HSS expression is potentially associated with HCC metastasis, particularly through the EMT pathway, remains largely unknown. In this study, the relationship between HSS expression and HCC metastasis was investigated in clinical samples of HCC. Meanwhile, the regulation of HCC metastasis and EMT progression by HSS were also analyzed in both in vitro and in vivo models. The results showed that the expression of 23 kDa HSS was significantly decreased among HCC tissues with angioinvasion. A decrease in HSS predicted poor prognosis with a lower survival rate. Furthermore, the growth of xenograft tumors after inoculating MHCC97H-HSS-shRNA (HCC) cells into nude mice was notably accelerated compared to those inoculated with HSS-expressing cells. Further analysis revealed that knockdown of HSS expression in both MHCC97H and HepG2 cells could enhance the migration of these HCC cells. Concurrently, interference of HSS expression by shRNA promoted conversion of morphologically epithelial-like HCC cells into mesenchymal-like cells, together with downregulations of epithelial markers (such as E-cadherin and zonula occludens-1) and upregulation of mesenchymal-like makers (such as α-SMA, ß-catenin, and fibronectin). Furthermore, it was demonstrated that, as well as promoting EMT, HSS-shRNA induced the phosphorylation of extracellular signal-regulated kinase (ERK) and elevated the expression of the EMT-related transcription factor Snail. Specific inhibition of HSS-shRNA-induced ERK phosphorylation by PD98059 attenuated HCC cell migration in a dose-dependent manner. In conclusion, we demonstrated that downregulation of HSS expression contributes to HCC metastasis partially through the ERK-activated EMT pathway.


Assuntos
Carcinoma Hepatocelular/metabolismo , Transição Epitelial-Mesenquimal/genética , Neoplasias Hepáticas/metabolismo , Sistema de Sinalização das MAP Quinases/genética , Peptídeos/genética , Peptídeos/metabolismo , Animais , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/patologia , Transição Epitelial-Mesenquimal/fisiologia , Feminino , Técnicas de Silenciamento de Genes , Células Hep G2 , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/patologia , Sistema de Sinalização das MAP Quinases/fisiologia , Masculino , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Peptídeos/química , Peptídeos/fisiologia
10.
Stem Cell Res Ther ; 8(1): 183, 2017 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-28807057

RESUMO

BACKGROUND: Although they are expandable in vitro, hepatic progenitors are immature cells and share many immunomarkers with hepatocellular carcinoma, raising potential concerns regarding maltransformation after transplantation. This study investigated the effects of hepatic nuclear factor (HNF) 4α on the proliferation, migration, and maltransformation of hepatic progenitors and determined the feasibility of using these manipulated cells for transplantation. METHODS: The effects of HNF4α on rat hepatic progenitors (i.e. hepatic oval cells) were analyzed by HNF4α overexpression and HNF4α shRNA. Nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice injured by carbon chloride (CCl4) were then transplanted with control, HNF4α-overexpressing or HNF4α-suppressing hepatic oval cells. Finally, the engraftment of these cells in the recipient liver was analyzed. RESULTS: Rat hepatic progenitors (i.e. hepatic oval cells) expressed HNF4α, although less than that in hepatocytes. When HNF4α was overexpressed in these cells, the proliferation and migration of hepatic oval cells were reduced; but when HNF4α was suppressed by shRNA, the proliferation and migration, and even anchorage-independent growth, of these cells were accelerated. RNA microarray and gene functional analysis revealed that suppressing HNF4α not only impaired many biosynthesis and metabolism pathways of hepatocytes but also increased pathways for cancer. When transplanted into CCl4-injured NOD/SCID mice, few HNF4α-suppressing hepatic oval cells localized into the liver, while control cells and HNF4α-overexpressing cells engrafted into the liver and differentiated into albumin-positive hepatocytes. Interestingly, the hepatocytes derived from HNF4α-overexpressing cells were less migrative and expressed less c-Myc than the cells derived from control cells. CONCLUSION: HNF4α constrains proliferation, migration, and maltransformation of hepatic progenitors, and HNF4α-overexpressing hepatic progenitors serve as an optimal candidate for cell transplantation.


Assuntos
Movimento Celular , Transformação Celular Neoplásica/metabolismo , Transformação Celular Neoplásica/patologia , Fator 4 Nuclear de Hepatócito/metabolismo , Fígado/patologia , Células-Tronco/metabolismo , Animais , Tetracloreto de Carbono , Proliferação de Células , Regulação da Expressão Gênica , Hepatócitos/metabolismo , Hepatócitos/transplante , Camundongos Endogâmicos NOD , Camundongos SCID , Proteínas Proto-Oncogênicas c-myc/metabolismo , Ratos
11.
Cell Mol Life Sci ; 74(20): 3827-3840, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28612217

RESUMO

Adaptive immunity plays a critical role in IR and T2DM development; however, the biological mechanisms linking T cell costimulation and glucose metabolism have not been fully elucidated. In this study, we demonstrated that the costimulatory molecule OX40 controls T cell activation and IR development. Inflammatory cell accumulation and enhanced proinflammatory gene expression, as well as high OX40 expression levels on CD4+ T cells, were observed in the adipose tissues of mice with diet-induced obesity. OX40-KO mice exhibited significantly less weight gain and lower fasting glucose levels than those of WT mice, without obvious adipose tissue inflammation. The effects of OX40 on IR are mechanistically linked to the promotion of T cell activation, Th1 cell differentiation and proliferation-as well as the attenuation of Treg suppressive activity and the enhancement of proinflammatory cytokine production-in adipose tissues. Furthermore, OX40 expression on T cells was positively associated with obesity in humans, suggesting that our findings are clinically relevant. In summary, our study revealed that OX40 in CD4+ T cells is crucial for adipose tissue inflammation and IR development. Therefore, the OX40 signaling pathway may be a new target for preventing or treating obesity-related IR and T2DM.


Assuntos
Tecido Adiposo/imunologia , Inflamação/imunologia , Resistência à Insulina , Obesidade/imunologia , Receptores OX40/imunologia , Tecido Adiposo/metabolismo , Animais , Linfócitos T CD4-Positivos/imunologia , Células Cultivadas , Humanos , Inflamação/etiologia , Inflamação/genética , Ativação Linfocitária , Macrófagos/imunologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Obesidade/complicações , Obesidade/genética , Receptores OX40/genética , Linfócitos T Reguladores/imunologia , Células Th1/imunologia , Regulação para Cima
12.
Int Immunopharmacol ; 41: 56-65, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27816727

RESUMO

Monitoring T lymphocyte proliferation, especially in vivo, is essential for the evaluation of adaptive immune reactions. Flow cytometry-based proliferation assays have advantages in measuring cell division of different T lymphocyte subsets at the same time by multicolor labelling. In this study, we aimed to establish the use of 5-Ethynyl-2'-deoxyuridine (EdU) incorporation in vivo to monitor T lymphocyte proliferation by flow cytometry with an adoptive transfer model. We found that fixation followed by permeabilization preserved T cell surface antigens and had no obvious effects on the fluorescence intensity of APC, PE, PE-Cy7, FITC and PerCP-Cy5.5 when the concentration of the permeabilization reagents was optimized. However, the click reaction resulted in a significant decrease in the fluorescence intensity of PE and PE-Cy7, and surface staining after the click reaction improved the fluorescence intensity. Thus, an extra step of blocking with PBS with 3% FBS between the click reaction and cell surface staining is needed. Furthermore, the percentage of EdU-positive cells increased in a dose-dependent manner, and the saturated dose of EdU was 20mg/kg. Intraperitoneal and intravenous injection had no differences in lymphocyte proliferation detection with EdU in vivo. In addition, T cell proliferation measured by EdU incorporation was comparable to BrdU but was lower than CFSE labelling. In conclusion, we optimized the protocols for EdU administration in vivo and staining in vitro, providing a feasible method for the measurement of T lymphocyte proliferation with EdU incorporation by flow cytometry in vivo.


Assuntos
Desoxiuridina/análogos & derivados , Citometria de Fluxo/métodos , Coloração e Rotulagem/métodos , Linfócitos T/efeitos dos fármacos , Animais , Proliferação de Células/efeitos dos fármacos , Química Click , Desoxiuridina/farmacologia , Corantes Fluorescentes/farmacologia , Masculino , Camundongos Endogâmicos C57BL , Octoxinol/farmacologia , Saponinas/farmacologia , Linfócitos T/citologia , Linfócitos T/metabolismo
13.
Stem Cells Int ; 2016: 6304385, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-26955393

RESUMO

Profibrogenesis cytokine, transforming growth factor- (TGF-) ß1, induces hepatic progenitors experiencing epithelial to mesenchymal transition (EMT) to matrix synthesis cells, even tumor initiating cells. Our previous data found that epidermal growth factor (EGF) blocks and reverses TGF-ß1-induced transition. The aim of this study is to determine the characteristic changes of hepatic progenitors after TGF-ß1-induced transition and EGF-induced reversion. Hepatic oval cells, rat hepatic progenitors, were isolated from rats fed a choline-deficient diet supplemented with ethionine. TGF-ß1-containing medium was used for inducing EMT, while EGF-containing medium was used for reversing EMT. During TGF-ß1-induced transition and EGF-induced reversion, hepatic oval cells sustained their progenitor cell marker expression, including α-fetoprotein, albumin, and cytokeratin-19. The proliferation ability and differentiation potential of these cells were suppressed by TGF-ß1, while EGF resumed these capacities to the level similar to the control cells. RNA microarray analysis showed that most of the genes with significant changes after TGF-ß1 incubation were recovered by EGF. Signal pathway analysis revealed that TGF-ß1 impaired the pathways of cell cycle and cytochrome P450 detoxification, and EGF reverted TGF-ß1 effects through activating MAPK and PI3K-Akt pathway. EGF reverses the characteristics impaired by TGF-ß1 in hepatic oval cells, serving as a protective cytokine to hepatic progenitors.

14.
J Transl Med ; 14: 57, 2016 Feb 24.
Artigo em Inglês | MEDLINE | ID: mdl-26911290

RESUMO

BACKGROUND: Double-negative (DN) T cells could delay the onset and the progression of autoimmune diabetes, yet they were less efficient on reversing autoimmune diabetes. The aim of this study was to investigate whether the combination of DN T cells and anti-thymocyte serum (ATS) could reverse new-onset diabetes in NOD mice. METHODS: The regulation of different subsets of T cells in vitro and in vivo by ATS and DN T cells were examined using flow cytometry. At the day of diabetes onset, ATS was administered on the same day and 2 days later, and DN T cells were transferred at day 7. The reversion of diabetes was assessed by monitoring blood glucose levels. RESULTS: The efficacy of inhibition of DN T cells on CD8(+) T cells was lower than that on CD4(+) T cells both in vitro and in vivo. ATS resulted in a significant depletion of CD8(+) T cells, while DN T cells were less sensitive to ATS depletion. 80 % diabetic NOD mice achieved long term (6 months) reversion of diabetes by combined ATS and DN T cells treatment, compared to 16 % in ATS single treatment and none in DN T cell single treatment. DN T cells preferentially resided in spleen and pancreatic draining lymph nodes in ATS plus DN T cells treated NOD mice. CONCLUSIONS: DN T cells plus ATS therapy show promising reversion effects on diabetic NOD mice due to a shift of balance from a destructive T cell response to one that favors DN T cell regulation.


Assuntos
Soro Antilinfocitário/uso terapêutico , Diabetes Mellitus Tipo 1/tratamento farmacológico , Diabetes Mellitus Tipo 1/imunologia , Linfócitos T/imunologia , Animais , Soro Antilinfocitário/farmacologia , Linfócitos T CD4-Positivos/imunologia , Linfócitos T CD8-Positivos/imunologia , Feminino , Linfonodos/efeitos dos fármacos , Linfonodos/patologia , Depleção Linfocítica , Masculino , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos NOD , Baço/efeitos dos fármacos , Baço/imunologia , Baço/patologia , Linfócitos T/efeitos dos fármacos
15.
Am J Physiol Gastrointest Liver Physiol ; 309(2): G112-22, 2015 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-25977511

RESUMO

Hepatic stimulator substance, also known as augmenter of liver regeneration (ALR), is a novel hepatic mitogen that stimulates liver regeneration after partial hepatectomy (PH). Recent work has indicated that a lack of ALR expression inhibited liver regeneration in rats, and the mechanism seems to be related to increased cell apoptosis. The mitochondria play an important role during liver regeneration. Adequate ATP supply, which is largely dependent on effective mitochondrial biogenesis, is essential for progress of liver regeneration. However, ALR gene expression during liver regeneration, particularly its function with mitochondrial DNA synthesis, remains poorly understood. In this study, ALR expression in hepatocytes of mice was suppressed with ALR short-hairpin RNA interference or ALR deletion (knockout, KO). The ALR-defective mice underwent PH, and the liver was allowed to regenerate for 1 wk. Analysis of liver growth and its correlation with mitochondrial biogenesis showed that both ALR mRNA and protein levels increased robustly in control mice with a maximum at days 3 and 4 post-PH. However, ALR knockdown inhibited hepatic DNA synthesis and decelerated liver regeneration after PH. Furthermore, both in the ALR-knockdown and ALR-KO mice, expression of mitochondrial transcription factor A and peroxisome proliferator-activated receptor-γ coactivator-1α were reduced, resulting in impaired mitochondrial biogenesis. In conclusion, ALR is apparently required to ensure appropriate liver regeneration following PH in mice, and deletion of the ALR gene may delay liver regeneration in part due to impaired mitochondrial biogenesis.


Assuntos
Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Replicação do DNA , DNA Mitocondrial/biossíntese , Regeneração Hepática , Fígado/metabolismo , Mitocôndrias Hepáticas/metabolismo , Oxirredutases atuantes sobre Doadores de Grupo Enxofre/metabolismo , Animais , Tetracloreto de Carbono , Proliferação de Células , Doença Hepática Induzida por Substâncias e Drogas/genética , Doença Hepática Induzida por Substâncias e Drogas/patologia , Doença Hepática Induzida por Substâncias e Drogas/fisiopatologia , Modelos Animais de Doenças , Regulação da Expressão Gênica , Hepatectomia , Fígado/patologia , Fígado/fisiopatologia , Fígado/cirurgia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Mitocôndrias Hepáticas/patologia , Renovação Mitocondrial , Oxirredutases atuantes sobre Doadores de Grupo Enxofre/deficiência , Oxirredutases atuantes sobre Doadores de Grupo Enxofre/genética , Interferência de RNA , RNA Mensageiro/metabolismo , Transdução de Sinais , Fatores de Tempo
16.
Stem Cells Dev ; 23(14): 1675-87, 2014 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-24640968

RESUMO

Hepatic stimulator substance (HSS), also known as augmenter of liver regeneration (ALR), acts as a hepatotrophic growth factor to promote liver regeneration after liver damage or partial hepatectomy. However, the expression and function of HSS during liver development in mammals remain largely unknown. In this work, the hepatoblasts were isolated from mice at embryonic day 13.5 (E13.5), and HSS expression and its role during hepatoblast maturation were investigated. The results showed that HSS expression was enhanced in the hepatoblasts compared with mouse primary hepatocytes. HSS expression (23 kDa) was significantly decreased if the hepatoblast maturation was induced by a combination of oncostatin M (OSM), dexamethasone (DEX), and hepatocyte growth factor (HGF). We also found that knockdown of HSS expression (mainly 23-kDa isoform) by siRNA promoted hepatoblast maturation and also activated the signal transducer and activator of transcription 3 (STAT3) phosphorylation levels. However, if STAT3 activity was blocked by a small-molecule inhibitor Stattic, then hepatocyte maturation could be abolished, suggesting that STAT3 was most likely a potential molecule responsible for HSS signaling. In summary, our results demonstrated for the first time that HSS might be an active factor participating in the regulation of liver development and hepatocyte maturation.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Regeneração Hepática , Fígado/crescimento & desenvolvimento , Peptídeos/metabolismo , Animais , Dexametasona/administração & dosagem , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Fator de Crescimento de Hepatócito/administração & dosagem , Hepatócitos/efeitos dos fármacos , Peptídeos e Proteínas de Sinalização Intercelular , Fígado/citologia , Fígado/embriologia , Fígado/lesões , Camundongos , Oncostatina M/administração & dosagem , Peptídeos/genética
17.
Int J Biochem Cell Biol ; 47: 38-46, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24309469

RESUMO

Hepatic stimulatory substance (HSS), which encodes a sulfhydryl oxidase enzyme, promotes liver regeneration (LR) and maintains the viability of hepatocytes. Surprisingly, we found that the levels of the HSS mRNA and expressed protein were both strongly repressed at 12h after a 70% partial hepatectomy (PH) in mice. Understanding the mechanism and effect of this extraordinary suppression can provide a novel path for exploring the molecular function of HSS during LR. We observed that the EGF levels in the serum were negatively correlated with HSS expression in regenerating livers. Treating primary mouse hepatocytes or Hepa1-6 cells with EGF suppressed HSS mRNA expression. This suppression was transcriptional and was mediated by the effect of EGF on the phosphorylation of CCAAT/enhancer-binding protein ß (C/EBPß), which regulates HSS expression. We further showed that the enhanced phosphorylation of C/EBPß after PH promoted its interaction with the HSS promoter and repressed HSS expression at early time-points after PH. Interestingly, the knockdown of HSS caused a dramatic decrease in E-cadherin expression in hepatocytes. E-cadherin expression was also significantly suppressed at 12h after PH. Moreover, the pre-injection of HSS-expressing adenovirus vectors prevented E-cadherin suppression after PH. Treatment with C/EBPß siRNA reversed the EGF-mediated inhibition of HSS expression and led to enhanced E-cadherin expression and reduced cell migration. Our findings suggest that C/EBPß directly inhibits the HSS promoter after PH and that this inhibition can downregulate E-cadherin expression. These data provide novel insight into the potential role of HSS in hepatic structural reconstruction during LR.


Assuntos
Caderinas/antagonistas & inibidores , Caderinas/biossíntese , Regeneração Hepática/fisiologia , Peptídeos/metabolismo , Animais , Linhagem Celular Tumoral , Movimento Celular/fisiologia , Regulação para Baixo , Fator de Crescimento Epidérmico/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , Neoplasias Hepáticas Experimentais , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Transfecção
18.
Biochem J ; 431(2): 277-87, 2010 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-20690902

RESUMO

hHSS (human hepatic stimulator substance), acting as a hepatotrophic growth factor, promotes liver regeneration. However, the regulatory mechanisms for hHSS transcription are still poorly understood. In the present study, we investigated transcription of hHSS triggered by EGF (epidermal growth factor) and the role of C/EBPß (CCAAT/enhancer-binding protein ß) as a potential core factor responsible for hHSS transcription in HepG2 cells. The results show that EGF suppresses hHSS mRNA expression at early time points. Using a promoter deletion assay, we identified a proximal region (-358/-212) that is required for EGF suppression. Overexpression of C/EBPß enhances EGF suppression of hHSS, and mutation of the C/EBPß-binding site at -292/-279 or siRNA (short interfering RNA) interference abolishes EGF suppression. Furthermore, using an electrophoretic mobility-shift assay and chromatin immunoprecipitation analysis, we found that C/EBPß specifically binds to the -292/-279 site that is responsible for EGF inhibition. Moreover, using a knockin (overexpression) and knockdown strategy (siRNA), we confirmed that C/EBPß is a key factor responsible for inhibition of hHSS mRNA expression. Pre-treatment with an inhibitor of JNK (c-Jun N-terminal kinase) or down-regulation of JNK1 with specific siRNA reverses EGF-inhibited hHSS expression. Our results provide a crucial regulatory mechanism for EGF in hHSS transcription within the promoter proximal region.


Assuntos
Proteína beta Intensificadora de Ligação a CCAAT/química , Regulação para Baixo/efeitos dos fármacos , Fator de Crescimento Epidérmico/farmacologia , Peptídeos/genética , Motivos de Aminoácidos , Sequência de Bases , Sítios de Ligação , Proteína beta Intensificadora de Ligação a CCAAT/metabolismo , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Inativação Gênica/efeitos dos fármacos , Células Hep G2 , Humanos , Peptídeos e Proteínas de Sinalização Intercelular , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Dados de Sequência Molecular , Peptídeos/metabolismo , Regiões Promotoras Genéticas/genética , Transcrição Genética/efeitos dos fármacos
19.
Biomaterials ; 31(27): 7196-204, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20573394

RESUMO

This paper aims to establish a relationship between the surface morphology induced micromechanics and bone remodeling responses to a solid bead coated porous implant and further to develop a multiobjective optimization framework for the coating design of biomaterials. Multiscale modeling and remodeling techniques were developed, where a macroscopic analysis was initially performed to generate a global response to enable a microscopic analysis. The bone remodeling responses of the microscopic models (with a specific surface morphology) were evaluated in terms of the average apparent density developed in the peri-implant region. To explore the proposed multiscale analysis and design methods, a typical dental implantation setting is exemplified in this study. The response surface method (RSM) was utilized to relate the major implant coating parameters to the bone responses. It is found that increasing the volume fraction of the coating beads/particles results in a greater bone density, whereas increasing bead/particle size does not significantly affect the bone's responses. Several different multiobjective optimization schemes were adopted to optimize the coated bead size and volume fraction, which reveal that the optimal design parameters of particle diameter and volume fraction are 100 microm--35% and 38 microm--17.5% for the cortical and cancellous bones respectively, agreeing with clinical data. To maximize the implant/bone interfacial stability, specific surface coating designs for particular locations are recommended.


Assuntos
Osseointegração/fisiologia , Próteses e Implantes , Materiais Revestidos Biocompatíveis/química , Implantes Dentários , Planejamento de Prótese Dentária , Modelos Teóricos , Propriedades de Superfície
20.
Opt Express ; 18(7): 6693-702, 2010 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-20389692

RESUMO

Achieving negative permittivity and negative permeability signifies a key topic of research in the design of metamaterials. This paper introduces a level-set based topology optimization method, in which the interface between the vacuum and metal phases is implicitly expressed by the zero-level contour of a higher dimensional level-set function. Following a sensitivity analysis, the optimization maximizes the objective based on the normal direction of the level-set function and induced current flow, thereby generating the desirable patterns of current flow on metal surface. As a benchmark example, the U-shaped structure and its variations are obtained from the level-set topology optimization. Numerical examples demonstrate that both negative permittivity and negative permeability can be attained.


Assuntos
Campos Eletromagnéticos , Óptica e Fotônica , Algoritmos , Simulação por Computador , Fenômenos Eletromagnéticos , Desenho de Equipamento , Teste de Materiais , Metais/química , Modelos Estatísticos , Modelos Teóricos , Permeabilidade
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