Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 15 de 15
Filter
Add more filters










Publication year range
1.
Database (Oxford) ; 20242024 May 06.
Article in English | MEDLINE | ID: mdl-38713861

ABSTRACT

Cancer immunotherapy has brought about a revolutionary breakthrough in the field of cancer treatment. Immunotherapy has changed the treatment landscape for a variety of solid and hematologic malignancies. To assist researchers in efficiently uncovering valuable information related to cancer immunotherapy, we have presented a manually curated comprehensive database called DIRMC, which focuses on molecular features involved in cancer immunotherapy. All the content was collected manually from published literature, authoritative clinical trial data submitted by clinicians, some databases for drug target prediction such as DrugBank, and some experimentally confirmed high-throughput data sets for the characterization of immune-related molecular interactions in cancer, such as a curated database of T-cell receptor sequences with known antigen specificity (VDJdb), a pathology-associated TCR database (McPAS-TCR) et al. By constructing a fully connected functional network, ranging from cancer-related gene mutations to target genes to translated target proteins to protein regions or sites that may specifically affect protein function, we aim to comprehensively characterize molecular features related to cancer immunotherapy. We have developed the scoring criteria to assess the reliability of each MHC-peptide-T-cell receptor (TCR) interaction item to provide a reference for users. The database provides a user-friendly interface to browse and retrieve data by genes, target proteins, diseases and more. DIRMC also provides a download and submission page for researchers to access data of interest for further investigation or submit new interactions related to cancer immunotherapy targets. Furthermore, DIRMC provides a graphical interface to help users predict the binding affinity between their own peptide of interest and MHC or TCR. This database will provide researchers with a one-stop resource to understand cancer immunotherapy-related targets as well as data on MHC-peptide-TCR interactions. It aims to offer reliable molecular characteristics support for both the analysis of the current status of cancer immunotherapy and the development of new immunotherapy. DIRMC is available at http://www.dirmc.tech/. Database URL: http://www.dirmc.tech/.


Subject(s)
Immunotherapy , Neoplasms , Immunotherapy/methods , Humans , Neoplasms/immunology , Neoplasms/genetics , Neoplasms/therapy , Receptors, Antigen, T-Cell/immunology , Receptors, Antigen, T-Cell/genetics , Databases, Protein , User-Computer Interface
2.
Plant Methods ; 20(1): 23, 2024 Feb 04.
Article in English | MEDLINE | ID: mdl-38311750

ABSTRACT

BACKGROUND: Camellia oleifera, an essential woody oil tree in China, propagates through grafting. However, in production, it has been found that the interaction between rootstocks and scions may affect fruit characteristics. Therefore, it is necessary to predict fruit characteristics after grafting to identify suitable rootstock types. METHODS: This study used Deep Neural Network (DNN) methods to analyze the impact of 106 6-year-old grafting combinations on the characteristics of C.oleifera, including fruit and seed characteristics, and fatty acids. The prediction of characteristics changes after grafting was explored to provide technical support for the cultivation and screening of specialized rootstocks. After determining the unsaturated fat acids, palmitoleic acid C16:1, cis-11 eicosenoic acid C20:1, oleic acid C18:1, linoleic acid C18:2, linolenic acid C18:3, kernel oil content, fruit height, fruit diameter, fresh fruit weight, pericarp thickness, fresh seed weight, and the number of fresh seeds, the DNN method was used to calculate and analyze the model. The model was screened using the comprehensive evaluation index of Mean Absolute Error (MAPE), determinate correlation R2 and and time consumption. RESULTS: When using 36 neurons in 3 hidden layers, the deep neural network model had a MAPE of less than or equal to 16.39% on the verification set and less than or equal to 13.40% on the test set. Compared with traditional machine learning methods such as support vector machines and random forests, the DNN method demonstrated more accurate predictions for fruit phenotypic characteristics, with MAPE improvement rates of 7.27 and 3.28 for the 12 characteristics on the test set and maximum R2 improvement values of 0.19 and 0.33. In conclusion, the DNN method developed in this study can effectively predict the oil content and fruit phenotypic characteristics of C. oleifera, providing a valuable tool for predicting the impact of grafting combinations on the fruit of C. oleifera.

3.
Bioinformatics ; 39(2)2023 02 03.
Article in English | MEDLINE | ID: mdl-36645245

ABSTRACT

MOTIVATION: Synthetic lethality (SL) is a form of genetic interaction that can selectively kill cancer cells without damaging normal cells. Exploiting this mechanism is gaining popularity in the field of targeted cancer therapy and anticancer drug development. Due to the limitations of identifying SL interactions from laboratory experiments, an increasing number of research groups are devising computational prediction methods to guide the discovery of potential SL pairs. Although existing methods have attempted to capture the underlying mechanisms of SL interactions, methods that have a deeper understanding of and attempt to explain SL mechanisms still need to be developed. RESULTS: In this work, we propose a novel SL prediction method, SLGNN. This method is based on the following assumption: SL interactions are caused by different molecular events or biological processes, which we define as SL-related factors that lead to SL interactions. SLGNN, apart from identifying SL interaction pairs, also models the preferences of genes for different SL-related factors, making the results more interpretable for biologists and clinicians. SLGNN consists of three steps: first, we model the combinations of relationships in the gene-related knowledge graph as the SL-related factors. Next, we derive initial embeddings of genes through an explicit message aggregation process of the knowledge graph. Finally, we derive the final gene embeddings through an SL graph, constructed using known SL gene pairs, utilizing factor-based message aggregation. At this stage, a supervised end-to-end training model is used for SL interaction prediction. Based on experimental results, the proposed SLGNN model outperforms all current state-of-the-art SL prediction methods and provides better interpretability. AVAILABILITY AND IMPLEMENTATION: SLGNN is freely available at https://github.com/zy972014452/SLGNN.


Subject(s)
Neoplasms , Synthetic Lethal Mutations , Humans , Pattern Recognition, Automated , Neoplasms/genetics , Neoplasms/drug therapy , Neural Networks, Computer , Drug Development
4.
Elife ; 112022 09 20.
Article in English | MEDLINE | ID: mdl-36125130

ABSTRACT

During obesity and high fat-diet (HFD) feeding in mice, sustained low-grade inflammation includes not only increased pro-inflammatory macrophages in the expanding adipose tissue, but also bone marrow (BM) production of invasive Ly6Chigh monocytes. As BM adiposity also accrues with HFD, we explored the relationship between the gains in BM white adipocytes and invasive Ly6Chigh monocytes by in vivo and ex vivo paradigms. We find a temporal and causal link between BM adipocyte whitening and the Ly6Chigh monocyte surge, preceding the adipose tissue macrophage rise during HFD in mice. Phenocopying this, ex vivo treatment of BM cells with conditioned media from BM adipocytes or bona fide white adipocytes favoured Ly6Chigh monocyte preponderance. Notably, Ly6Chigh skewing was preceded by monocyte metabolic reprogramming towards glycolysis, reduced oxidative potential and increased mitochondrial fission. In sum, short-term HFD changes BM cellularity, resulting in local adipocyte whitening driving a gradual increase and activation of invasive Ly6Chigh monocytes.


Subject(s)
Bone Marrow , Monocytes , Adipocytes , Animals , Culture Media, Conditioned , Mice , Mice, Inbred C57BL , Monocytes/metabolism , Obesity/metabolism
5.
Autophagy ; 18(4): 829-840, 2022 04.
Article in English | MEDLINE | ID: mdl-34432599

ABSTRACT

Depolarized mitochondria can be degraded via mitophagy, a selective form of autophagy. The RAB GTPase RAB7A was recently shown to play a key role in this process. RAB7A regulates late endocytic trafficking under normal growth conditions but is translocated to the mitochondrial surface following depolarization. However, how RAB7A activity is regulated during mitophagy is not understood. Here, using a proximity-dependent biotinylation approach (miniTurbo), we identified C5orf51 as a specific interactor of GDP-locked RAB7A. C5orf51 also interacts with the RAB7A guanine nucleotide exchange factor (GEF) complex members MON1 and CCZ1. In the absence of C5orf51, localization of RAB7A on depolarized mitochondria is compromised and the protein is degraded by the proteasome. Furthermore, depletion of C5orf51 also inhibited ATG9A recruitment to depolarized mitochondria. Together, these results indicate that C5orf51 is a positive regulator of RAB7A in its shuttling between late endosomes and mitochondria to enable mitophagy.Abbreviations: ATG9A: autophagy related 9A; Baf A1: bafilomycin A1; BioID: proximity-dependent biotin identification; CCCP: carbonyl cyanide m-chlorophenylhydrazone; CCZ1: CCZ1 homolog, vacuolar protein trafficking and biogenesis associated; DQ-BSA: dye quenched-bovine serum albumin; FYCO1: FYVE and coiled-coil domain autophagy adaptor 1; GAP: GTPase activating protein; GEF: guanine nucleotide exchange factor; KO: knockout; LRPPRC: leucine rich pentatricopeptide repeat containing; MG132: carbobenzoxy-Leu-Leu-leucinal; MON1: MON1 homolog, secretory trafficking associated; mtDNA: mitochondrial DNA; PINK1: PTEN induced kinase 1; PRKN/PARKIN: parkin RBR E3 ubiquitin protein ligase; RMC1: regulator of MON1-CCZ1; TBC1D15: TBC1 domain family member 15; TBC1D17: TBC1 domain family member 17; TOMM20: translocase of outer mitochondrial membrane 20; WDR91: WD repeat domain 91; WT: wild type.


Subject(s)
Autophagy , Mitophagy , Autophagy/physiology , DNA, Mitochondrial , Endosomes/metabolism , Guanine Nucleotide Exchange Factors , Mitophagy/genetics , Ubiquitin-Protein Ligases/metabolism
6.
JCI Insight ; 6(23)2021 12 08.
Article in English | MEDLINE | ID: mdl-34673575

ABSTRACT

Immune cells exhibit low-level, constitutive signaling at rest (tonic signaling). Such tonic signals are required for fundamental processes, including the survival of B lymphocytes, but when they are elevated by genetic or environmental causes, they can lead to autoimmunity. Events that control ongoing signal transduction are, therefore, tightly regulated by submembrane cytoskeletal polymers like F-actin. The actin-binding proteins that underpin the process, however, are poorly described. By investigating patients with ARPC1B deficiency, we report that ARPC1B-containing ARP2/3 complexes are stimulated by Wiskott Aldrich Syndrome protein (WASP) to nucleate the branched actin networks that control tonic signaling from the B cell receptor (BCR). Despite an upregulation of ARPC1A, ARPC1B-deficient cells were not capable of WASP-mediated nucleation by ARP2/3, and this caused the loss of WASP-dependent structures, including podosomes in macrophages and lamellipodia in B cells. In the B cell compartment, ARPC1B deficiency also led to weakening of the cortical F-actin cytoskeleton that normally curtails the diffusion of BCRs and ultimately resulted in increased tonic lipid signaling, oscillatory calcium release from the endoplasmic reticulum (ER), and phosphorylated Akt. These events contributed to skewing the threshold for B cell activation in response to microbial-associated molecular patterns (MAMPs). Thus, ARPC1B is critical for ARP2/3 complexes to control steady-state signaling of immune cells.


Subject(s)
Actin-Related Protein 2-3 Complex/adverse effects , Actins/metabolism , B-Lymphocytes/metabolism , Wiskott-Aldrich Syndrome Protein/metabolism , Humans , Polymerization
7.
J Cell Sci ; 133(11)2020 06 08.
Article in English | MEDLINE | ID: mdl-32393599

ABSTRACT

Podosomes play crucial roles in macrophage adhesion and migration. Wiskott-Aldrich syndrome protein (WASP; also known as WAS)-mediated actin polymerization is one of the key events initiating podosome formation. Nevertheless, membrane signals to trigger WASP activation at macrophage podosomes remain unclear. Here, we show that phosphatidylinositol (3,4,5)-trisphosphate [PI(3,4,5)P3] lipids are enriched at the podosome and stably recruit WASP rather than the WASP-5KE mutant. Phosphatidylinositol 4,5-bisphosphate 3-kinase catalytic subunit ß (PIK3CB) is spatially located at the podosome core. Inhibition of PIK3CB and overexpression of phosphatase and tensin homolog (PTEN) impede F-actin polymerization of the podosome. PIK3CB activation is regulated by Abl1 and Src family kinases. At the podosome core, Src and Hck promote the phosphorylation of Tyr488 in the consensus Y-x-x-M motif of Abl1, which enables the association of phosphoinositide 3-kinase (PI3K) regulatory subunits. Knockdown of Abl1 rather than Abl2 suppresses the PI3K/Akt pathway, regardless of Src and Hck activities. Reintroduction of wild-type Abl1 rather than the Abl1-Y488F mutant rescues PI3KR1 recruitment and PI3K activation. When PIK3CB, Abl1 or Src/Hck is suppressed, macrophage podosome formation, matrix degradation and chemotactic migration are inhibited. Thus, Src/Hck-mediated phosphorylation of Abl1 Tyr488 triggers PIK3CB-dependent PI(3,4,5)P3 production and orchestrates the assembly and function of macrophage podosomes.


Subject(s)
Podosomes , Actins/genetics , Actins/metabolism , Macrophages/metabolism , Phosphatidylinositol 3-Kinase , Phosphatidylinositol 3-Kinases/genetics , Phosphatidylinositol 3-Kinases/metabolism , Phosphorylation , Podosomes/metabolism
8.
Commun Biol ; 3(1): 117, 2020 03 13.
Article in English | MEDLINE | ID: mdl-32170110

ABSTRACT

Integrin receptors orchestrate cell adhesion and cytoskeletal reorganization. The endocytic mechanism of integrin-ß3 receptor at the podosome remains unclear. Using viscous RGD-membrane as the model system, here we show that the formation of podosome-like adhesion promotes Dab2/clathrin-mediated endocytosis of integrin-ß3. Integrin-ß3 and RGD ligand are endocytosed from the podosome and sorted into the endosomal compartment. Inhibitions of podosome formation and knockdowns of Dab2 and clathrin reduce RGD endocytosis. F-actin assembly at the podosome core exhibits protrusive contact towards the substrate and results in plasma membrane invaginations at the podosome ring. BIN1 specifically associates with the region of invaginated membrane and recruits DNM2. During the podosome formation, BIN1 and DNM2 synchronously enrich at the podosome ring and trigger clathrin dissociation and RGD endocytosis. Knockdowns of BIN1 and DNM2 suppress RGD endocytosis. Thus, plasma membrane invagination caused by F-actin polymerization promotes BIN1-dependent DNM2 recruitment and facilitate integrin-ß3 endocytosis at the podosome.


Subject(s)
Cell Membrane/metabolism , Endocytosis/genetics , Fibroblasts/metabolism , Integrin beta3/metabolism , Membranes, Artificial , Oligopeptides/metabolism , Podosomes/metabolism , Actins/metabolism , Adaptor Proteins, Signal Transducing/genetics , Adaptor Proteins, Signal Transducing/metabolism , Adaptor Proteins, Vesicular Transport/genetics , Adaptor Proteins, Vesicular Transport/metabolism , Animals , Cell Adhesion , Cells, Cultured , Clathrin/genetics , Clathrin/metabolism , Dynamin II/genetics , Dynamin II/metabolism , Gene Knockdown Techniques , Humans , Integrin beta3/genetics , Ligands , Mice , Nerve Tissue Proteins/genetics , Nerve Tissue Proteins/metabolism , Polymerization , Rats , Transfection , Tumor Suppressor Proteins/genetics , Tumor Suppressor Proteins/metabolism
9.
Mol Biol Cell ; 30(5): 622-635, 2019 03 01.
Article in English | MEDLINE | ID: mdl-30601698

ABSTRACT

During podosome formation, distinct phosphatidylinositol 3,4,5-trisphosphate lipid (PI(3,4,5)P3) production and F-actin polymerization take place at integrin-mediated adhesions. Membrane-associated actin regulation factors, such as myosin-1, serve as key molecules to link phosphatidylinositol signals to podosome assembly. Here, we report that long-tailed myosin-1e (Myo1e) is enriched at the ventral layer of the podosome core in a PI(3,4,5)P3-dependent manner. The combination of TH1 and TH2 (TH12) of Myo1e tail domains contains the essential motif for PI(3,4,5)P3-dependent membrane association and ventral localization at the podosome. TH12 KR2A (K772A and R782A) becomes dissociated from the plasma membrane. While F-actin polymerizations are initialized from the ventral layer of the podosome, TH12 precedes the recruitment of N-WASP and Arp2/3 in the initial phase of podosome formation. Overexpression of TH12, not TH12 KR2A, impedes PI(3,4,5)P3 signaling, restrains F-actin polymerization, and inhibits podosome formation. TH12 also suppresses gelatin degradation and migration speed of invadopodia-forming A375 melanoma cells. Thus, TH12 domain of Myo1e serves as a regulatory component to connect phosphatidylinositol signaling to F-actin polymerization at the podosome.


Subject(s)
Actins/metabolism , Myosins/chemistry , Myosins/metabolism , Phosphatidylinositols/metabolism , Podosomes/metabolism , Polymerization , Signal Transduction , Animals , Cell Line, Tumor , Cell Membrane/metabolism , Gelatin/metabolism , Humans , Mice , Phosphatidylinositol Phosphates/metabolism , Protein Binding , Protein Domains , RAW 264.7 Cells , Rats
10.
Cell Death Dis ; 8(5): e2818, 2017 05 25.
Article in English | MEDLINE | ID: mdl-28542133

ABSTRACT

Protein disulfide isomerase (PDI) involves cell survival and death. Whether PDI mediates mechanical stretch stress (SS) and/or advanced glycosylation end products (AGEs) -triggered simultaneous increases in proliferation and apoptosis of vascular smooth muscle cells (VSMCs) is unknown. Here, we hypothesized that different expression levels of PDI trigger completely opposite cell fates among the different VSMC subtypes. Mouse veins were grafted into carotid arteries of non-diabetic and diabetic mice for 8 weeks; the grafted veins underwent simultaneous increases in proliferation and apoptosis, which triggered vein graft arterializations in non-diabetic or atherosclerosis in diabetic mice. A higher rate of proliferation and apoptosis was seen in the diabetic group. SS and/or AGEs stimulated the quiescent cultured VSMCs, resulting in simultaneous increases in proliferation and apoptosis; they could induce increased PDI activation and expression. Both in vivo and in vitro, the proliferating VSMCs indicated weak co-expression of PDI and SM-α-actin while apoptotic or dead cells showed strong co-expression of both. Either SS or AGEs rapidly upregulated the expression of PDI, NOX1 and ROS, and their combination had synergistic effects. Inhibiting PDI simultaneously suppressed the proliferation and apoptosis of VSMCs, while inhibition of SM-α-actin with cytochalasin D led to increased apoptosis and cleaved caspases-3 but had no effect on proliferation. In conclusion, different expression levels of PDI in VSMCs induced by SS and/or AGEs triggered a simultaneous increase in proliferation and apoptosis, accelerated vein graft arterializations or atherosclerosis, leading us to propose PDI as a novel target for the treatment of vascular remodeling and diseases.


Subject(s)
Apoptosis , Atherosclerosis/etiology , Diabetes Mellitus, Experimental/pathology , Glycation End Products, Advanced/toxicity , Myocytes, Smooth Muscle/metabolism , Protein Disulfide-Isomerases/metabolism , Stress, Mechanical , Veins/surgery , Animals , Apoptosis/drug effects , Atherosclerosis/pathology , Blood Vessel Prosthesis , Cell Proliferation/drug effects , Diabetes Mellitus, Experimental/complications , Diabetes Mellitus, Experimental/enzymology , Enzyme Inhibitors/pharmacology , Glycosylation , Male , Mice, Inbred C57BL , Muscle, Smooth, Vascular/pathology , Myocytes, Smooth Muscle/drug effects , NADPH Oxidase 1 , RNA, Small Interfering/metabolism , Reactive Oxygen Species/metabolism , Signal Transduction/drug effects , Up-Regulation
11.
Am J Physiol Endocrinol Metab ; 310(5): E355-66, 2016 Mar 01.
Article in English | MEDLINE | ID: mdl-26670486

ABSTRACT

Advanced glycation end products (AGEs) disturb bone remodeling during aging, and this process is accelerated in diabetes. However, their role in modulation of osteoclast-induced bone resorption is controversial, with some studies indicating that AGEs enhance bone resorption and others showing the opposite effect. We determined whether AGEs present at different stages of osteoclast differentiation affect bone resorption differently. Based on increased levels of tartrate-resistant acid phosphatase (TRAP) and cathepsin K (CTSK), we identified day 4 of induction as the dividing time of cell fusion stage and mature stage in RAW264.7 cell-derived osteoclast-like cells (OCLs). AGE-modified BSA (50-400 µg/ml) or control BSA (100 µg/ml) was then added at the beginning of each stage. Results showed that the presence of AGEs at the cell fusion stage reduced pit numbers, resorption area, and CTSK expression. Moreover, expression of receptor activator of nuclear factor-κB (RANK) as well as the number of TRAP-positive cells, nuclei per OCL, actin rings, and podosomes also decreased. However, the presence of AGEs at the mature stage enlarged the resorption area markedly and increased pit numbers slightly. Intriguingly, only the number of nuclei per OCL and podosomes increased. These data indicate that AGEs biphasically modulate bone resorption activity of OCLs in a differentiation stage-dependent manner. AGEs at the cell fusion stage reduce bone resorption dramatically, mainly via suppression of RANK expression in osteoclast precursors, whereas AGEs at the mature stage enhance bone resorption slightly, most likely by increasing the number of podosomes in mature OCLs.


Subject(s)
Bone Remodeling/drug effects , Bone Resorption/metabolism , Cell Differentiation/drug effects , Glycation End Products, Advanced/pharmacology , Osteoclasts/drug effects , Acid Phosphatase/metabolism , Actins/drug effects , Actins/metabolism , Animals , Blotting, Western , Cathepsin K/metabolism , Cell Line , Cell Nucleus/drug effects , Immunohistochemistry , Isoenzymes/metabolism , Mice , Osteoclasts/cytology , Osteoclasts/metabolism , Podosomes/drug effects , Podosomes/metabolism , Real-Time Polymerase Chain Reaction , Receptor Activator of Nuclear Factor-kappa B/drug effects , Receptor Activator of Nuclear Factor-kappa B/metabolism , Tartrate-Resistant Acid Phosphatase
12.
Nat Commun ; 6: 8672, 2015 Oct 28.
Article in English | MEDLINE | ID: mdl-26507506

ABSTRACT

The turnover of integrin receptors is critical for cell migration and adhesion dynamics. Here we find that force development at integrins regulates adaptor protein recruitment and endocytosis. Using mobile RGD (Arg-Gly-Asp) ligands on supported lipid membranes (RGD membranes) and rigid RGD ligands on glass (RGD-glass), we find that matrix force-dependent integrin signals block endocytosis. Dab2, an adaptor protein of clathrin-mediated endocytosis, is not recruited to activated integrin-beta3 clusters on RGD-glass; however, it is recruited to integrin-mediated adhesions on RGD membranes. Further, when force generation is inhibited on RGD-glass, Dab2 binds to integrin-beta3 clusters. Dab2 binding to integrin-beta3 excludes other adhesion-related adaptor proteins, such as talin. The clathrin-mediated endocytic machinery combines with Dab2 to facilitate the endocytosis of RGD-integrin-beta3 clusters. From these observations, we propose that loss of traction force on ligand-bound integrin-beta3 causes recruitment of Dab2/clathrin, resulting in endocytosis of integrins.


Subject(s)
Cells/chemistry , Cells/metabolism , Clathrin/metabolism , Endocytosis , Integrin beta3/metabolism , Adaptor Proteins, Signal Transducing , Adaptor Proteins, Vesicular Transport/genetics , Adaptor Proteins, Vesicular Transport/metabolism , Animals , Apoptosis Regulatory Proteins , Biomechanical Phenomena , Cell Movement , Cells/cytology , Clathrin/genetics , HeLa Cells , Humans , Integrin beta3/genetics , Mice , Protein Binding , Traction
13.
PLoS One ; 10(10): e0141375, 2015.
Article in English | MEDLINE | ID: mdl-26488175

ABSTRACT

AIMS: This study was designed to demonstrate simultaneous increases in proliferation and apoptosis of vascular smooth muscle cells (VSMCs) leading to accelerated vein graft remodeling and to explore the underlying mechanisms. METHODS: Vein grafts were performed in non-diabetic and diabetic mice. The cultured quiescent VSMCs were subjected to mechanical stretch stress (SS) and/or advanced glycosylation end products (AGEs). Harvested vein grafts and treated VSMCs were used to detect cell proliferation, apoptosis, mitogen-activated protein kinases (MAPKs) activation and SM-α-actin expression. RESULTS: Significantly thicker vessel walls and greater increases in proliferation and apoptosis were observed in diabetic vein grafts than those in non-diabetic. Both SS and AGEs were found to induce different activation of three members of MAPKs and simultaneous increases in proliferation and apoptosis of VSMCs, and combined treatment with both had a synergistic effect. VSMCs with strong SM-α-actin expression represented more activated JNKs or p38MAPK, and cell apoptosis, while the cells with weak SM-α-actin expression demonstrated preferential activation of ERKs and cell proliferation. In contrast, inhibition of MAPKs signals triggered significant decreases in VSMC proliferation, and apoptosis. Treatment of the cells with RNA interference of receptor of AGEs (RAGE) also resulted in significant decreases in both proliferation and apoptosis. CONCLUSIONS: Increased pressure-induced SS triggers simultaneous increases in proliferation and apoptosis of VSMCs in the vein grafts leading to vein arterializations, which can be synergistically accelerated by high glucose-induced AGEs resulting in vein graft atherosclerosis. Either SS or AGEs and their combination induce simultaneous increases in proliferation and apoptosis of VSMCs via different activation of three members of MAPKs resulting from different VSMC subtypes classified by SM-α-actin expression levels.


Subject(s)
Apoptosis/physiology , Atherosclerosis/physiopathology , Cell Proliferation/physiology , Diabetes Mellitus, Experimental/physiopathology , Muscle, Smooth, Vascular/physiology , Myocytes, Smooth Muscle/physiology , Veins/physiology , Actins/metabolism , Animals , Atherosclerosis/metabolism , Cells, Cultured , Diabetes Mellitus, Experimental/metabolism , Male , Mice , Mice, Inbred C57BL , Mitogen-Activated Protein Kinases/metabolism , Muscle, Smooth, Vascular/metabolism , Myocytes, Smooth Muscle/metabolism , RNA Interference/physiology , Signal Transduction/physiology , Stress, Mechanical , Veins/metabolism , p38 Mitogen-Activated Protein Kinases/metabolism
14.
Cell Physiol Biochem ; 35(5): 1857-67, 2015.
Article in English | MEDLINE | ID: mdl-25871260

ABSTRACT

BACKGROUND/AIMS: Prosthesis loosening is closely associated with chronic inflammatory cytokine secretion by macrophages, which are activated by wear particles or inflammatory stimulants such as lipopolysaccharide (LPS). Reactive oxygen species (ROS) are critical regulators of inflammation, but their enzymatic sources in response to wear particles and their effects on peri-implant LPS-tolerance remain unclear. METHODS: Three ROS-related enzymes-nicotinamide adenine dinucleotide phosphate oxidase (NOX)-1 and -2 and catalase-were investigated in interface membrane tissues and in titanium (Ti) particle-stimulated macrophages in vitro. The generation of ROS and downstream inflammatory effects were measured with or without pre-incubation with apocynin, an NOX inhibitor. RESULTS: Pre-exposure to Ti particles attenuated NF-κB activation in LPS-stimulated macrophages, indicating that wear particles suppress immune response, which may lead to chronic inflammation. NOX-1 and -2 were highly expressed in aseptically loosened interface membranes and in macrophages stimulated with Ti particles; the particles induced a moderate amount of ROS generation, NF-κB activation, and TNF-α secretion in macrophages, and these effects were suppressed by apocynin. CONCLUSION: Wear particles induce ROS generation through the NOX signaling pathway, resulting in persistent inflammation and delayed loosening. Thus, the suppression of NOX activity may be a useful strategy for preventing prosthesis loosening.


Subject(s)
Inflammation , NADPH Oxidases/metabolism , Reactive Oxygen Species/metabolism , Acetophenones/pharmacology , Adult , Aged , Animals , Catalase/metabolism , Cell Line , Enzyme Inhibitors/pharmacology , Female , Humans , Lipopolysaccharides/toxicity , Macrophages/cytology , Macrophages/drug effects , Macrophages/metabolism , Male , Mice , Middle Aged , NADPH Oxidases/antagonists & inhibitors , NF-kappa B/metabolism , Particle Size , Phosphorylation/drug effects , Prostheses and Implants , Signal Transduction , Titanium/chemistry , Titanium/pharmacology , Tumor Necrosis Factor-alpha/metabolism
15.
Inflammation ; 38(3): 1289-96, 2015.
Article in English | MEDLINE | ID: mdl-25577344

ABSTRACT

Implant-related infection (IRI) is closely related to the local immunity of peri-implant tissues. The generation of reactive oxygen species (ROS) in activated macrophages plays a prominent role in the innate immune response. In previous studies, we indicated that implant wear particles promote endotoxin tolerance by decreasing the release of proinflammatory cytokines. However, it is unclear whether ROS are involved in the damage of the local immunity of peri-implant tissues. In the present study, we assessed the mechanism of local immunosuppression using titanium (Ti) particles and/or lipopolysaccharide (LPS) to stimulate RAW 264.7 cells. The results indicate that the Ti particles induced the generation of a moderate amount of ROS through nicotinamide adenine dinucleotide phosphate oxidase-1, but not through catalase. Pre-exposure to Ti particles inhibited ROS generation and extracellular-regulated protein kinase activation in LPS-stimulated macrophages. These findings indicate that chronic stimulation by Ti particles may lead to a state of oxidative stress and persistent inflammation, which may result in the attenuation of the immune response of macrophages to bacterial components such as LPS. Eventually, immunosuppression develops in peri-implant tissues, which may be a risk factor for IRI.


Subject(s)
Extracellular Signal-Regulated MAP Kinases/metabolism , Macrophage Activation/immunology , Macrophages/immunology , Prostheses and Implants/adverse effects , Reactive Oxygen Species/metabolism , Animals , Arthroplasty, Replacement/adverse effects , Catalase/metabolism , Cell Line , Immunity, Innate , Inflammation/immunology , Lipopolysaccharides/immunology , Mice , NADH, NADPH Oxidoreductases/metabolism , NADPH Oxidase 1 , Oxidative Stress , Phosphorylation , Titanium/immunology
SELECTION OF CITATIONS
SEARCH DETAIL
...