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1.
Immunity ; 48(1): 75-90.e6, 2018 01 16.
Artigo em Inglês | MEDLINE | ID: mdl-29343442

RESUMO

The molecular basis of signal-dependent transcriptional activation has been extensively studied in macrophage polarization, but our understanding remains limited regarding the molecular determinants of repression. Here we show that IL-4-activated STAT6 transcription factor is required for the direct transcriptional repression of a large number of genes during in vitro and in vivo alternative macrophage polarization. Repression results in decreased lineage-determining transcription factor, p300, and RNA polymerase II binding followed by reduced enhancer RNA expression, H3K27 acetylation, and chromatin accessibility. The repressor function of STAT6 is HDAC3 dependent on a subset of IL-4-repressed genes. In addition, STAT6-repressed enhancers show extensive overlap with the NF-κB p65 cistrome and exhibit decreased responsiveness to lipopolysaccharide after IL-4 stimulus on a subset of genes. As a consequence, macrophages exhibit diminished inflammasome activation, decreased IL-1ß production, and pyroptosis. Thus, the IL-4-STAT6 signaling pathway establishes an alternative polarization-specific epigenenomic signature resulting in dampened macrophage responsiveness to inflammatory stimuli.


Assuntos
Interleucina-4/metabolismo , Macrófagos/metabolismo , Fator de Transcrição STAT6/metabolismo , Animais , Western Blotting , Linhagem Celular , Elementos Facilitadores Genéticos , Citometria de Fluxo , Regulação da Expressão Gênica , Inflamassomos/metabolismo , Citometria de Varredura a Laser , Lipopolissacarídeos/farmacologia , Macrófagos/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Reação em Cadeia da Polimerase , Piroptose/genética , Transdução de Sinais/genética , Transdução de Sinais/fisiologia
2.
Curr Issues Mol Biol ; 45(6): 4948-4969, 2023 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-37367064

RESUMO

Adenosine plays an important role in modulating immune cell function, particularly T cells and myeloid cells, such as macrophages and dendritic cells. Cell surface adenosine A2A receptors (A2AR) regulate the production of pro-inflammatory cytokines and chemokines, as well as the proliferation, differentiation, and migration of immune cells. In the present study, we expanded the A2AR interactome and provided evidence for the interaction between the receptor and the Niemann-Pick type C intracellular cholesterol transporter 1 (NPC1) protein. The NPC1 protein was identified to interact with the C-terminal tail of A2AR in RAW 264.7 and IPMФ cells by two independent and parallel proteomic approaches. The interaction between the NPC1 protein and the full-length A2AR was further validated in HEK-293 cells that permanently express the receptor and RAW264.7 cells that endogenously express A2AR. A2AR activation reduces the expression of NPC1 mRNA and protein density in LPS-activated mouse IPMФ cells. Additionally, stimulation of A2AR negatively regulates the cell surface expression of NPC1 in LPS-stimulated macrophages. Furthermore, stimulation of A2AR also altered the density of lysosome-associated membrane protein 2 (LAMP2) and early endosome antigen 1 (EEA1), two endosomal markers associated with the NPC1 protein. Collectively, these results suggested a putative A2AR-mediated regulation of NPC1 protein function in macrophages, potentially relevant for the Niemann-Pick type C disease when mutations in NPC1 protein result in the accumulation of cholesterol and other lipids in lysosomes.

3.
Int J Mol Sci ; 24(13)2023 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-37445813

RESUMO

The ABC transporter P-glycoprotein (Pgp) has been found to be involved in multidrug resistance in tumor cells. Lipids and cholesterol have a pivotal role in Pgp's conformations; however, it is often difficult to investigate it with conventional structural biology techniques. Here, we applied robust approaches coupled with cross-linking mass spectrometry (XL-MS), where the natural lipid environment remains quasi-intact. Two experimental approaches were carried out using different cross-linkers (i) on living cells, followed by membrane preparation and immunoprecipitation enrichment of Pgp, and (ii) on-bead, subsequent to membrane preparation and immunoprecipitation. Pgp-containing complexes were enriched employing extracellular monoclonal anti-Pgp antibodies on magnetic beads, followed by on-bead enzymatic digestion. The LC-MS/MS results revealed mono-links on Pgp's solvent-accessible residues, while intraprotein cross-links confirmed a complex interplay between extracellular, transmembrane, and intracellular segments of the protein, of which several have been reported to be connected to cholesterol. Harnessing the MS results and those of molecular docking, we suggest an epitope for the 15D3 cholesterol-dependent mouse monoclonal antibody. Additionally, enriched neighbors of Pgp prove the strong connection of Pgp to the cytoskeleton and other cholesterol-regulated proteins. These findings suggest that XL-MS may be utilized for protein structure and network analyses in such convoluted systems as membrane proteins.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP , Espectrometria de Massas em Tandem , Animais , Camundongos , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Simulação de Acoplamento Molecular , Cromatografia Líquida , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Colesterol/metabolismo
4.
Int J Mol Sci ; 24(15)2023 Aug 02.
Artigo em Inglês | MEDLINE | ID: mdl-37569709

RESUMO

The human P-glycoprotein (P-gp), a transporter responsible for multidrug resistance, is present in the plasma membrane's raft and non-raft domains. One specific conformation of P-gp that binds to the monoclonal antibody UIC2 is primarily associated with raft domains and displays heightened internalization in cells overexpressing P-gp, such as in NIH-3T3 MDR1 cells. Our primary objective was to investigate whether the trafficking of this particular P-gp conformer is dependent on cholesterol levels. Surprisingly, depleting cholesterol using cyclodextrin resulted in an unexpected increase in the proportion of raft-associated P-gp within the cell membrane, as determined by UIC2-reactive P-gp. This increase appears to be a compensatory response to cholesterol loss from the plasma membrane, whereby cholesterol-rich raft micro-domains are delivered to the cell surface through an augmented exocytosis process. Furthermore, this exocytotic event is found to be part of a complex trafficking mechanism involving lysosomal exocytosis, which contributes to membrane repair after cholesterol reduction induced by cyclodextrin treatment. Notably, cells overexpressing P-gp demonstrated higher total cellular cholesterol levels, an increased abundance of stable lysosomes, and more effective membrane repair following cholesterol modifications. These modifications encompassed exocytotic events that involved the transport of P-gp-carrying rafts. Importantly, the enhanced membrane repair capability resulted in a durable phenotype for MDR1 expressing cells, as evidenced by significantly improved viabilities of multidrug-resistant Pgp-overexpressing immortal NIH-3T3 MDR1 and MDCK-MDR1 cells compared to their parents when subjected to cholesterol alterations.


Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP , Ciclodextrinas , Humanos , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/genética , Membro 1 da Subfamília B de Cassetes de Ligação de ATP/metabolismo , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Membrana Celular/metabolismo , Ciclodextrinas/farmacologia , Colesterol/metabolismo , Microdomínios da Membrana/metabolismo
5.
Arch Biochem Biophys ; 722: 109184, 2022 06 15.
Artigo em Inglês | MEDLINE | ID: mdl-35395253

RESUMO

The roles and molecular interactions of polyamines (PAs) in the nucleus are not fully understood. Here their effect on nucleosome stability, a key regulatory factor in eukaryotic gene control, is reported, as measured in agarose embedded nuclei of H2B-GFP expressor HeLa cells. Nucleosome stability was assessed by quantitative microscopy [1,2] in situ, in close to native state of chromatin, preserving the nucleosome constrained topology of the genomic DNA. A robust destabilizing effect was observed in the millimolar concentration range in the case of spermine, spermidine as well as putrescine, which was strongly pH and salt concentration-dependent, and remained significant also at neutral pH. The integrity of genomic DNA was not affected by PA treatment, excluding DNA break-elicited topological relaxation as a factor in destabilization. The binding of PAs to DNA was demonstrated by the displacement of ethidium bromide, both from deproteinized nuclear halos and from plasmid DNA. The possibility that DNA methylation patterns may be influenced by PA levels is contemplated in the context of gene expression and DNA methylation correlations identified in the NCI-60 panel-based CellMiner database: methylated loci in subsets of high-ODC1 cell lines and the dependence of PER3 DNA methylation on PA metabolism.


Assuntos
Nucleossomos , Poliaminas , DNA/química , Células HeLa , Humanos , Poliaminas/metabolismo , Putrescina/metabolismo , Espermidina/química , Espermidina/metabolismo
6.
Int J Mol Sci ; 23(9)2022 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-35563567

RESUMO

Beige adipocytes with thermogenic function are activated during cold exposure in white adipose tissue through the process of browning. These cells, similar to brown adipocytes, dissipate stored chemical energy in the form of heat with the help of uncoupling protein 1 (UCP1). Recently, we have shown that tissue transglutaminase (TG2) knock-out mice have decreased cold tolerance in parallel with lower utilization of their epididymal adipose tissue and reduced browning. To learn more about the thermogenic function of this fat depot, we isolated preadipocytes from the epididymal adipose tissue of wild-type and TG2 knock-out mice and differentiated them in the beige direction. Although differentiation of TG2 knock-out preadipocytes is phenotypically similar to the wild-type cells, the mitochondria of the knock-out beige cells have multiple impairments including an altered electron transport system generating lower electrochemical potential difference, reduced oxygen consumption, lower UCP1 protein content, and a higher portion of fragmented mitochondria. Most of these differences are present in preadipocytes as well, and the differentiation process cannot overcome the functional disadvantages completely. TG2 knock-out beige adipocytes produce more iodothyronine deiodinase 3 (DIO3) which may inactivate thyroid hormones required for the establishment of optimal mitochondrial function. The TG2 knock-out preadipocytes and beige cells are both hypometabolic as compared with the wild-type controls which may also be explained by the lower expression of solute carrier proteins SLC25A45, SLC25A47, and SLC25A42 which transport acylcarnitine, Co-A, and amino acids into the mitochondrial matrix. As a consequence, the mitochondria in TG2 knock-out beige adipocytes probably cannot reach the energy-producing threshold required for normal thermogenic functions, which may contribute to the decreased cold tolerance of TG2 knock-out mice.


Assuntos
Proteína 2 Glutamina gama-Glutamiltransferase , Termogênese , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/metabolismo , Animais , Camundongos , Mitocôndrias/genética , Mitocôndrias/metabolismo , Termogênese/genética , Proteína Desacopladora 1/genética , Proteína Desacopladora 1/metabolismo
7.
Exp Cell Res ; 377(1-2): 47-55, 2019 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-30794803

RESUMO

Brown and beige adipocytes contribute significantly to the regulation of whole body energy expenditure and systemic metabolic homeostasis not exclusively by thermogenesis through mitochondrial uncoupling. Several studies have provided evidence in rodents that brown and beige adipocytes produce a set of adipokines ("batokines") which regulate local tissue homeostasis and have beneficial effects on physiological functions of the entire body. We observed elevated secretion of Interleukin (IL)-6, IL-8 and monocyte chemoattractant protein (MCP)-1, but not tumor necrosis factor alpha (TNFα) or IL-1ß pro-inflammatory cytokines, by ex vivo differentiating human beige adipocytes (induced by either PPARγ agonist or irisin) compared to white. Higher levels of IL-6, IL-8 and MCP-1 were released from human deep neck adipose tissue biopsies (enriched in browning cells) than from subcutaneous ones. IL-6 was produced in a sustained manner and mostly by the adipocytes and not by the undifferentiated progenitors. Continuous blocking of IL-6 receptor by specific antibody during beige differentiation resulted in downregulation of brown marker genes and increased morphological changes that are characteristic of white adipocytes. The data suggest that beige adipocytes adjust their production of IL-6 to reach an optimal level for differentiation in the medium enhancing browning in an autocrine manner.


Assuntos
Adipócitos Bege/citologia , Adipócitos Bege/metabolismo , Tecido Adiposo Marrom/fisiologia , Diferenciação Celular , Interleucina-6/metabolismo , Adulto , Idoso , Células Cultivadas , Quimiocina CCL2/metabolismo , Metabolismo Energético , Humanos , Interleucina-8/metabolismo , Pessoa de Meia-Idade , Consumo de Oxigênio , Adulto Jovem
8.
Biochim Biophys Acta ; 1861(3): 188-95, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26704667

RESUMO

The 15D3 mouse monoclonal antibody (mAb) binds an uncharacterized extracellular epitope of the ATP Binding Cassette (ABC) transporter human P-glycoprotein (Pgp). Depletion of cell plasma membrane cholesterol by using methyl-ß-cyclodextrin or other chemically modified ß-cyclodextrins decreased the Pgp binding affinity of 15D3 mAb. UIC2 mAb, which is known to distinguish two conformers of this ABC transporter, binds only a fraction of cell surface Pgps. UIC2 mAb non-reactive pools of Pgp can be identified with other extracellular mAbs such as 15D3. Cyclosporin A (CsA) can shift non-reactive Pgps into their UIC2-reactive conformation: a phenomenon called the "UIC2 shift". Competition studies proposed these two mAbs share overlapping epitopes and can reveal conformational changes of Pgp that correlate (r=0.97) with the cholesterol content of cells. An apparent increase in competition of these mAbs suggested a conformational change similar to those found in the presence of CsA. However, the reason turned out not to be the UIC2-shift because cholesterol removal from the plasma membrane (PM) reduced the amount of detectable Pgps by 15D3 mAb. This study showed that 15D3 mAb bound to a conformation sensitive epitope of Pgp that was responsive to PM cholesterol levels. These conformational changes were gradual and not as great as the changes observed between the two conformers recognized by the UIC2 mAb.


Assuntos
Anticorpos Monoclonais/metabolismo , Colesterol/metabolismo , Microdomínios da Membrana/metabolismo , Subfamília B de Transportador de Cassetes de Ligação de ATP/química , Subfamília B de Transportador de Cassetes de Ligação de ATP/genética , Subfamília B de Transportador de Cassetes de Ligação de ATP/imunologia , Subfamília B de Transportador de Cassetes de Ligação de ATP/metabolismo , Animais , Anticorpos Monoclonais/imunologia , Especificidade de Anticorpos , Ligação Competitiva , Epitopos , Microdomínios da Membrana/efeitos dos fármacos , Camundongos , Células NIH 3T3 , Ligação Proteica , Conformação Proteica , Relação Estrutura-Atividade , Transfecção , beta-Ciclodextrinas/farmacologia
9.
Biochim Biophys Acta Mol Cell Biol Lipids ; 1862(12): 1575-1586, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-28774822

RESUMO

During cold-exposure 'beige' adipocytes with increased mitochondrial content are activated in white adipose tissue (WAT). These cells, similarly to brown adipose tissue (BAT), dissipate stored chemical energy in the form of heat with the help of uncoupling protein 1 (UCP1). We investigated the effect of tissue transglutaminase (TG2) ablation on the function of ATs in mice. Although TG2+/+ and TG2-/- mice had the same amount of WAT and BAT, we found that TG2+/+ animals could tolerate acute cold exposure for 4h, whereas TG2-/- mice only for 3h. Both TG2-/- and TG2+/+ animals used up half of the triacylglycerol content of subcutaneous WAT (SCAT) after 3h treatment; however, TG2-/- mice still possessed markedly whiter and higher amount of gonadal WAT (GONAT) as reflected in the larger size of adipocytes and lower free fatty acid levels in serum. Furthermore, lower expression of 'beige' marker genes such as UCP1, TBX1 and TNFRFS9 was observed after cold exposure in GONAT of TG2-/- mice, paralleled with a lower level of UCP1 protein and a decreased mitochondrial content. The detected changes in gene expression of Resistin and Adiponectin did not provoke glucose intolerance in the investigated TG2-/- mice, and TG2 deletion did not influence adrenaline, noradrenaline, glucagon and insulin production. Our data suggest that TG2 has a tissue-specific role in GONAT function and browning, which becomes apparent under acute cold exposure.


Assuntos
Aclimatação , Tecido Adiposo Branco/metabolismo , Temperatura Baixa , Ácidos Graxos/metabolismo , Proteínas de Ligação ao GTP/deficiência , Testículo/metabolismo , Transglutaminases/deficiência , Adiponectina/biossíntese , Adiponectina/genética , Tecido Adiposo Marrom/citologia , Tecido Adiposo Marrom/metabolismo , Tecido Adiposo Branco/citologia , Animais , Ácidos Graxos/genética , Masculino , Camundongos , Camundongos Knockout , Proteína 2 Glutamina gama-Glutamiltransferase , Resistina/biossíntese , Resistina/genética , Testículo/citologia
10.
Acta Derm Venereol ; 97(3): 325-331, 2017 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-27701668

RESUMO

Skin dendritic cells of patients with atopic dermatitis (AD) are well characterized, but less is known about their peripheral blood precursors. The aim of this study was to investigate the phenotypic features and chemokine production of myeloid pre-dendritic cells of patients with AD ex vivo and after stimulation with Staphylococcus enterotoxin B and thymic stromal lymphopoietin, representing an AD-like microenvironment. The expression of cell surface markers was measured by flow cytometry, while chemokine production was monitored with chemokine antibody array and confirmed by enzyme-linked immunoassays. AD pre-dendritic cells expressed higher levels of Fc?RI and the maturation and activation markers tended to be altered. They produced both AD (CCL17/18/22) and maturation-related (CCL3/4/5) chemokines at higher level than controls. The production of CCL3/4 and CCL18 were significantly higher even without AD-specific stimulation, while the production of CCL17 and CCL22 were significantly higher only after stimulation. These results indicate that circulating AD pre-dendritic cells are premature and bear atopic characteristics even without tissue-specific stimulation, suggesting that their development is not only influenced by the skin microenvironment, but even earlier by the local milieu in the blood.


Assuntos
Antígenos CD1/imunologia , Quimiocinas/imunologia , Células Dendríticas/imunologia , Dermatite Atópica/imunologia , Glicoproteínas/imunologia , Adulto , Antígenos CD1/metabolismo , Biomarcadores/metabolismo , Estudos de Casos e Controles , Células Cultivadas , Microambiente Celular , Quimiocinas/metabolismo , Criança , Citocinas/farmacologia , Células Dendríticas/efeitos dos fármacos , Células Dendríticas/metabolismo , Dermatite Atópica/sangue , Dermatite Atópica/diagnóstico , Enterotoxinas/farmacologia , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Glicoproteínas/metabolismo , Humanos , Imunofenotipagem/métodos , Masculino , Fenótipo , Proteômica/métodos , Receptores de IgE/imunologia , Receptores de IgE/metabolismo , Adulto Jovem , Linfopoietina do Estroma do Timo
11.
Urol Int ; 99(3): 267-271, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28253496

RESUMO

INTRODUCTION: The authors of this paper assessed the surgical management and outcome of renal cancers when tumor thrombus extended into the inferior vena cava (IVC). METHODS: From 2000 to 2015, 46 radical nephrectomies were performed on patients with tumor thrombus in the IVC. The mean age of the patients was 60 ± 11 years. Radical nephrectomy and thrombectomies were performed in a single session. There were 18 level-IV, 23 level-III, and 5 level-II tumor thrombi. The operations were performed using cardiopulmonary bypass in 14 patients, while deep hypothermic cardiac arrest was carried out in 4 cases. RESULTS: The mean size of the tumors was 9.4 ± 3.5 cm. Histology showed the tumor stages to be pT3b in 21cases, pT3c in 22, and pT4 in 3 patients. The mean follow-up period of the patients was 3.6 ± 3.0 years. During the follow-up period, local recurrence was observed in 7 patients, while distant metastases occurred in 8 cases. The median time to progression was 37 ± 27 months. The 5-year overall survival was 43.7%. CONCLUSIONS: Radical nephrectomy and thrombectomy provided reasonable long-term survival for patients with renal cancer and IVC thrombus. However, tumor progression was detected in 41.6%. The presence of tumor thrombus had a negative effect on tumor progression and survival.


Assuntos
Carcinoma de Células Renais/cirurgia , Neoplasias Renais/cirurgia , Células Neoplásicas Circulantes/patologia , Nefrectomia , Trombectomia , Veia Cava Inferior/cirurgia , Trombose Venosa/cirurgia , Adulto , Idoso , Idoso de 80 Anos ou mais , Carcinoma de Células Renais/mortalidade , Carcinoma de Células Renais/secundário , Ponte Cardiopulmonar , Parada Circulatória Induzida por Hipotermia Profunda , Intervalo Livre de Doença , Feminino , Humanos , Estimativa de Kaplan-Meier , Neoplasias Renais/mortalidade , Neoplasias Renais/patologia , Masculino , Pessoa de Meia-Idade , Recidiva Local de Neoplasia , Estadiamento de Neoplasias , Nefrectomia/efeitos adversos , Nefrectomia/mortalidade , Fatores de Risco , Trombectomia/efeitos adversos , Trombectomia/mortalidade , Fatores de Tempo , Resultado do Tratamento , Carga Tumoral , Veia Cava Inferior/patologia , Trombose Venosa/mortalidade , Trombose Venosa/patologia
12.
Fogorv Sz ; 108(3): 99-105, 2015 Sep.
Artigo em Húngaro | MEDLINE | ID: mdl-26731966

RESUMO

In dental implantation missing tooth or teeth are replaced by artificial root. To reduce the time required for the integration newest trends are the enhancement of bone formation around the implant by bioactive molecules, growth factors. Such a molecule is bone morphogenetic protein-2 (BMP-2) accepted by US Food and Drug Administration (FDA). In these kind of applications effect of BMP-2 is tested in vitro on appropriate cell lines. One of these cell lines is the osteoblast like human embrionic palatal mesenchymal cell line (HEPM). In our experiments the effect of BMP-2 homodimer treatment was investigated on the differentiation of HEPM cells to osteoblasts reflected by changes in morphology, and proliferation after a short, 3 days BMP-2 treatment. Results showed that after three days BMP-2 treatment facilitates cell attachment on a concentration dependent manner however changes in cell morphology and proliferation could not be observed. Continuing the BMP-2 treatment inhibitory effect was measured in cell proliferation, which may refer to cell differentiation.


Assuntos
Proteína Morfogenética Óssea 2/farmacologia , Células-Tronco Embrionárias/efeitos dos fármacos , Células-Tronco Mesenquimais/efeitos dos fármacos , Osteoblastos/efeitos dos fármacos , Palato/citologia , Diferenciação Celular , Linhagem Celular , Proliferação de Células/efeitos dos fármacos , Humanos
13.
Exp Dermatol ; 23(4): 276-8, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24499484

RESUMO

Because it is not known exactly when or where myeloid dendritic cells (mDCs) acquire their atopic dermatitis (AD)-specific T-cell-polarising ability in patients with this condition, we used laser scanning cytometry (LSC) to determine whether isolated peripheral blood mDCs from AD patients differed from cells from controls in their cytokine expression profiles de novo and after stimulation with Staphylococcus enterotoxin B (SEB) and thymic stromal lymphopoietin (TSLP), which represents an AD-like microenvironment. Unstimulated mDCs from AD patients showed pluripotent T-cell-polarising capacity, and the surrounding skin microenvironment was essential for the distinctive, disease-specific activity of mDCs (Th2-Th22 bias). We also emphasise that LSC is an attractive technique to study the effect of new DC-targeted therapeutic modalities in AD.


Assuntos
Citocinas/metabolismo , Células Dendríticas/metabolismo , Dermatite Atópica/imunologia , Células Mieloides/metabolismo , Estudos de Casos e Controles , Células Cultivadas , Dermatite Atópica/metabolismo , Humanos , Citometria de Varredura a Laser
14.
Cytometry A ; 83(9): 818-29, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23843167

RESUMO

Laser scanning cytometry (LSC) is a slide-based technique combining advantages of flow and image cytometry: automated, high-throughput detection of optical signals with subcellular resolution. Fluorescence resonance energy transfer (FRET) is a spectroscopic method often used for studying molecular interactions and molecular distances. FRET has been measured by various microscopic and flow cytometric techniques. We have developed a protocol for a commercial LSC instrument to measure FRET on a cell-by-cell or pixel-by-pixel basis on large cell populations, which adds a new modality to the use of LSC. As a reference sample for FRET, we used a fusion protein of a single donor and acceptor (ECFP-EYFP connected by a seven-amino acid linker) expressed in HeLa cells. The FRET efficiency of this sample was determined via acceptor photobleaching and used as a reference value for ratiometric FRET measurements. Using this standard allowed the precise determination of an important parameter (the alpha factor, characterizing the relative signal strengths from a single donor and acceptor molecule), which is indispensable for quantitative FRET calculations in real samples expressing donor and acceptor molecules at variable ratios. We worked out a protocol for the identification of adherent, healthy, double-positive cells based on light-loss and fluorescence parameters, and applied ratiometric FRET equations to calculate FRET efficiencies in a semi-automated fashion. To test our protocol, we measured the FRET efficiency between Fos-ECFP and Jun-EYFP transcription factors by LSC, as well as by confocal microscopy and flow cytometry, all yielding nearly identical results. Our procedure allows for accurate FRET measurements and can be applied to the fast screening of protein interactions. A pipeline exemplifying the gating and FRET analysis procedure using the CellProfiler software has been made accessible at our web site.


Assuntos
Transferência Ressonante de Energia de Fluorescência/métodos , Citometria de Varredura a Laser/métodos , Mapeamento de Interação de Proteínas/métodos , Linhagem Celular Tumoral , Células HeLa , Ensaios de Triagem em Larga Escala/métodos , Humanos , Proteínas Luminescentes/química , Fotodegradação , Proteínas Recombinantes de Fusão/química
15.
Cytometry A ; 83(10): 933-43, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23846866

RESUMO

Understanding adipocyte biology and its homeostasis is in the focus of current obesity research. We aimed to introduce a high-content analysis procedure for directly visualizing and quantifying adipogenesis and adipoapoptosis by laser scanning cytometry (LSC) in a large population of cell. Slide-based image cytometry and image processing algorithms were used and optimized for high-throughput analysis of differentiating cells and apoptotic processes in cell culture at high confluence. Both preadipocytes and adipocytes were simultaneously scrutinized for lipid accumulation, texture properties, nuclear condensation, and DNA fragmentation. Adipocyte commitment was found after incubation in adipogenic medium for 3 days identified by lipid droplet formation and increased light absorption, while terminal differentiation of adipocytes occurred throughout day 9-14 with characteristic nuclear shrinkage, eccentric nuclei localization, chromatin condensation, and massive lipid deposition. Preadipocytes were shown to be more prone to tumor necrosis factor alpha (TNFα)-induced apoptosis compared to mature adipocytes. Importantly, spontaneous DNA fragmentation was observed at early stage when adipocyte commitment occurs. This DNA damage was independent from either spontaneous or induced apoptosis and probably was part of the differentiation program. © 2013 International Society for Advancement of Cytometry.


Assuntos
Adipócitos/citologia , Adipogenia/fisiologia , Apoptose/fisiologia , Citometria de Varredura a Laser/métodos , Diferenciação Celular/fisiologia , Humanos , Interpretação de Imagem Assistida por Computador
16.
Front Nutr ; 10: 1207394, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37781121

RESUMO

Introduction: Brown adipose tissue (BAT) dissipates energy in the form of heat majorly via the mitochondrial uncoupling protein 1 (UCP1). The activation of BAT, which is enriched in the neck area and contains brown and beige adipocytes in humans, was considered as a potential therapeutic target to treat obesity. Therefore, finding novel agents that can stimulate the differentiation and recruitment of brown or beige thermogenic adipocytes are important subjects for investigation. The current study investigated how the availability of extracellular thiamine (vitamin B1), an essential cofactor of mitochondrial enzyme complexes that catalyze key steps in the catabolism of nutrients, affects the expression of thermogenic marker genes and proteins and subsequent functional parameters during ex vivo adipocyte differentiation. Methods: We differentiated primary human adipogenic progenitors that were cultivated from subcutaneous (SC) or deep neck (DN) adipose tissues in the presence of gradually increasing thiamine concentrations during their 14-day differentiation program. mRNA and protein expression of thermogenic genes were analyzed by RT-qPCR and western blot, respectively. Cellular respiration including stimulated maximal and proton-leak respiration was measured by Seahorse analysis. Results: Higher thiamine levels resulted in increased expression of thiamine transporter 1 and 2 both at mRNA and protein levels in human neck area-derived adipocytes. Gradually increasing concentrations of thiamine led to increased basal, cAMP-stimulated, and proton-leak respiration along with elevated mitochondrial biogenesis of the differentiated adipocytes. The extracellular thiamine availability during adipogenesis determined the expression levels of UCP1, PGC1a, CKMT2, and other browning-related genes and proteins in primary SC and DN-derived adipocytes in a concentration-dependent manner. Providing abundant amounts of thiamine further increased the thermogenic competency of the adipocytes. Discussion: Case studies in humans reported that thiamine deficiency was found in patients with type 2 diabetes and obesity. Our study raises the possibility of a novel strategy with long-term thiamine supplementation, which can enhance the thermogenic competency of differentiating neck area-derived adipocytes for preventing or combating obesity.

17.
18.
Pharmaceuticals (Basel) ; 15(3)2022 Mar 17.
Artigo em Inglês | MEDLINE | ID: mdl-35337160

RESUMO

Brown and beige adipocytes have multilocular lipid droplets, express uncoupling protein (UCP) 1, and promote energy expenditure. In rodents, when the stimulus of browning subsides, parkin-dependent mitophagy is activated and dormant beige adipocytes persist. In humans, however, the molecular events during the beige to white transition have not been studied in detail. In this study, human primary subcutaneous abdominal preadipocytes were differentiated to beige for 14 days, then either the beige culture conditions were applied for an additional 14 days or it was replaced by a white medium. Control white adipocytes were differentiated by their specific cocktail for 28 days. Peroxisome proliferator-activated receptor γ-driven beige differentiation resulted in increased mitochondrial biogenesis, UCP1 expression, fragmentation, and respiration as compared to white. Morphology, UCP1 content, mitochondrial fragmentation, and basal respiration of the adipocytes that underwent transition, along with the induction of mitophagy, were similar to control white adipocytes. However, white converted beige adipocytes had a stronger responsiveness to dibutyril-cAMP, which mimics adrenergic stimulus, than the control white ones. Gene expression patterns showed that the removal of mitochondria in transitioning adipocytes may involve both parkin-dependent and -independent pathways. Preventing the entry of beige adipocytes into white transition can be a feasible way to maintain elevated thermogenesis and energy expenditure.

19.
Orv Hetil ; 162(42): 1693-1697, 2021 10 17.
Artigo em Húngaro | MEDLINE | ID: mdl-34657001

RESUMO

Összefoglaló. Bevezetés: A kis méretu vesedaganatok között lényegesen gyakoribbak a benignus elváltozások, és a kis malignus tumorok biológiai tulajdonságai is kedvezobbek, mint a nagyobb daganatokéi. Célkituzés: Szerzok a kis méretu vesetumorok tulajdonságait vizsgáltuk különbözo alcsoportokban. Módszer: 2000. január 1. és 2015. január 1. között 1272 beteg esetén végeztünk mutétet vesedaganat miatt. Közülük 496 betegnek volt kis méretu vesetumora. A betegek átlagéletkora 59 ± 12 év volt. A betegeket a tumorméret alapján három csoportba osztottuk. Az 1. csoportban a daganat mérete ≤4 cm, a 2. csoportban ≤3 cm és a 3. csoportban ≤2 cm volt. Eredmények: Az eltávolított daganat nagysága átlagosan 29 ± 8 mm volt. A szövettan 418 esetben (84%) malignus, míg 78 alkalommal (16%) benignus elváltozást mutatott. A 2 cm-nél kisebb daganatoknál malignitás csak az esetek 73,2%-ában fordult elo. A malignus és a benignus tumorok méretében szignifikáns eltérés volt (p = 0,008). Rosszul differenciált daganat - grade 3. és 4. - az esetek 10,8%-ában, 14,4%-ában, illetve 20,7%-ában volt jelen, amikor a tumorméret kisebb mint 2 cm, 2,1-3 cm, illetve 3,1-4,0 cm volt. A vesecarcinomáknál az átlagosan 10 éves utánkövetési ido alatt progresszió az esetek 5,5%-ában fordult elo. Következtetés: A kis méretu vesetumor az összes vesedaganat 39%-át tette ki. Ezek nagy része malignus volt, és benignus elváltozás az esetek 16%-ában fordult elo. A malignitás elofordulása a 2 cm-nél kisebb tumoroknál volt a legalacsonyabb. A tumorméret szoros összefüggést mutatott a malignitás gyakoriságával és a daganat differenciáltságával. A kedvezo patológiai és biológiai eredmények alapján a 2 cm alatti daganatoknál felmerül annak lehetosége, hogy esetükben az aktív követés vagy minimálisan invazív kezelés alkalmazása kerüljön elotérbe. Orv Hetil. 2021; 162(42): 1693-1697. INTRODUCTION: The incidence of benign lesions is more common in small renal masses (SRMs) and biological behavior of small malignancies is better compared to larger ones. OBJECTIVE: The authors measured the characteristics of SRMs in different subgroups. METHOD: From January 1, 2000 to January 1, 2015, 1272 patients underwent surgery for renal tumors. In 496 of the 1272 cases, the patients had SRMs. The mean age of the patients was 59 ± 12 years. Based on the sizes, the SRMs were divided into three groups. The sizes of the renal tumors were ≤4 cm in Group 1, ≤3 cm in Group 2 and ≤2 cm in Group 3. RESULTS: The mean diameter of the removed SRMs was 29 ± 8 mm. Histology confirmed renal cell carcinoma in 418 cases (84%), while benign tumor was present in 78 patients (16%). However, with the tumor size ≤2 cm, malignancy was detected in 73.2% of the cases. There was a significant difference in the sizes of the malignant and the benign masses (p = 0.008). Grade 3 or 4 tumors were present in 10.8%, 14.4% and 20.7% when the tumor size was ≤2 cm, 2.1 to 3 cm, and 3.1 to 4 cm in diameter, respectively. During the mean 10-year follow-up period, tumor progression was detected only in 5.5% of malignancies. CONCLUSION: In 39% of all cases, the patients had SRMs. The majority of SRMs were malignant, and benign lesion occurred only in 16% of the cases. The incidence of malignant tumors was the lowest when the size of SRMs was ≤2 cm. The size of the tumor was highly associated with probability of malignancy and tumor grading. Based on the favorable pathological and biological results in tumors below 2 cm, active surveillance or minimally invasive treatment could be the preferred management. Orv Hetil. 2021; 162(42): 1693-1697.


Assuntos
Neoplasias Renais/patologia , Idoso , Humanos , Incidência , Pessoa de Meia-Idade
20.
Pharmaceuticals (Basel) ; 14(11)2021 Oct 25.
Artigo em Inglês | MEDLINE | ID: mdl-34832860

RESUMO

White adipocytes contribute to energy storage, accumulating lipid droplets, whereas brown and beige adipocytes mainly function in dissipating energy as heat primarily via the action of uncoupling protein 1 (UCP1). Bone morphogenic protein 7 (BMP7) was shown to drive brown adipocyte differentiation in murine interscapular adipose tissue. Here, we performed global RNA-sequencing and functional assays on adipocytes obtained from subcutaneous (SC) and deep-neck (DN) depots of human neck and differentiated with or without BMP7. We found that BMP7 did not influence differentiation but upregulated browning markers, including UCP1 mRNA and protein in SC and DN derived adipocytes. BMP7 also enhanced mitochondrial DNA content, levels of oxidative phosphorylation complex subunits, along with PGC1α and p-CREB upregulation, and fragmentation of mitochondria. Furthermore, both UCP1-dependent proton leak and UCP1-independent, creatine-driven substrate cycle coupled thermogenesis were augmented upon BMP7 addition. The gene expression analysis also shed light on the possible role of genes unrelated to thermogenesis thus far, including ACAN, CRYAB, and ID1, which were among the highest upregulated ones by BMP7 treatment in both types of adipocytes. Together, our study shows that BMP7 strongly upregulates thermogenesis in human neck area derived adipocytes, along with genes, which might have a supporting role in energy expenditure.

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