RESUMO
Effective interplay between the uterus and the embryo is essential for pregnancy establishment; however, convenient methods to screen embryo implantation success and maternal uterine response in experimental mouse models are currently lacking. Here, we report 3DMOUSEneST, a groundbreaking method for analyzing mouse implantation sites based on label-free higher harmonic generation microscopy, providing unprecedented insights into the embryo-uterine dynamics during early pregnancy. The 3DMOUSEneST method incorporates second-harmonic generation microscopy to image the three-dimensional structure formed by decidual fibrillar collagen, named 'decidual nest', and third-harmonic generation microscopy to evaluate early conceptus (defined as the embryo and extra-embryonic tissues) growth. We demonstrate that decidual nest volume is a measurable indicator of decidualization efficacy and correlates with the probability of early pregnancy progression based on a logistic regression analysis using Smad1/5 and Smad2/3 conditional knockout mice with known implantation defects. 3DMOUSEneST has great potential to become a principal method for studying decidual fibrillar collagen and characterizing mouse models associated with early embryonic lethality and fertility issues.
Assuntos
Decídua , Implantação do Embrião , Animais , Feminino , Implantação do Embrião/fisiologia , Gravidez , Camundongos , Útero/fisiologia , Embrião de Mamíferos , Camundongos Knockout , Imageamento Tridimensional/métodos , Camundongos Endogâmicos C57BLRESUMO
The extracellular matrix (ECM) is a complex meshwork of proteins that forms the scaffold of all tissues in multicellular organisms. It plays crucial roles in all aspects of life - from orchestrating cell migration during development, to supporting tissue repair. It also plays critical roles in the etiology or progression of diseases. To study this compartment, we have previously defined the compendium of all genes encoding ECM and ECM-associated proteins for multiple organisms. We termed this compendium the 'matrisome' and further classified matrisome components into different structural or functional categories. This nomenclature is now largely adopted by the research community to annotate '-omics' datasets and has contributed to advance both fundamental and translational ECM research. Here, we report the development of Matrisome AnalyzeR, a suite of tools including a web-based application and an R package. The web application can be used by anyone interested in annotating, classifying and tabulating matrisome molecules in large datasets without requiring programming knowledge. The companion R package is available to more experienced users, interested in processing larger datasets or in additional data visualization options.
Assuntos
Proteínas da Matriz Extracelular , Matriz Extracelular , Matriz Extracelular/metabolismo , Proteínas da Matriz Extracelular/genética , Proteínas da Matriz Extracelular/metabolismo , Movimento CelularRESUMO
The roles of the extracellular matrix molecule tenascin-C (TNC) in health and disease have been extensively reviewed since its discovery over 40â years ago. Here, we will describe recent insights into the roles of TNC in tumorigenesis, angiogenesis, immunity and metastasis. In addition to high levels of expression in tumors, and during chronic inflammation, and bacterial and viral infection, TNC is also expressed in lymphoid organs. This supports potential roles for TNC in immunity control. Advances using murine models with engineered TNC levels were instrumental in the discovery of important functions of TNC as a danger-associated molecular pattern (DAMP) molecule in tissue repair and revealed multiple TNC actions in tumor progression. TNC acts through distinct mechanisms on many different cell types with immune cells coming into focus as important targets of TNC in cancer. We will describe how this knowledge could be exploited for cancer disease management, in particular for immune (checkpoint) therapies.
Assuntos
Neoplasias , Tenascina , Animais , Carcinogênese/genética , Carcinogênese/metabolismo , Matriz Extracelular/metabolismo , Camundongos , Neoplasias/genética , Neoplasias/metabolismo , Tenascina/genética , Tenascina/metabolismoRESUMO
Breast cancer is both the most common type of cancer and the most frequent cause of cancer mortality in women, mainly because of its heterogeneity and limited immunogenicity. The aim of specific active cancer immunotherapy is to stimulate the host's immune response against cancer cells directly using a vaccine platform carrying one or more tumor antigens. In particular, the ideal tumor antigen should be able to elicit T cell and B cell responses, be specific for the tumor and be expressed at high levels on cancer cells. Neoantigens are ideal targets for immunotherapy because they are exclusive to individual patient's tumors, are absent in healthy tissues and are not subject to immune tolerance mechanisms. Thus, neoantigens should generate a specific reaction towards tumors since they constitute the largest fraction of targets of tumor-infiltrating T cells. In this review, we describe the technologies used for neoantigen discovery, the heterogeneity of neoantigens in breast cancer and recent studies of breast cancer immunotherapy targeting neoantigens.
Assuntos
Antígenos de Neoplasias/imunologia , Neoplasias da Mama/imunologia , Neoplasias da Mama/terapia , Vacinas Anticâncer/imunologia , Imunidade , Imunoterapia/métodos , Animais , Antígenos de Neoplasias/classificação , Neoplasias da Mama/genética , Vacinas Anticâncer/administração & dosagem , Feminino , Humanos , MutaçãoRESUMO
[Figure: see text].
Assuntos
Aorta/enzimologia , Doenças da Aorta/prevenção & controle , Aterosclerose/prevenção & controle , Técnicas de Inativação de Genes , Fígado/enzimologia , Placa Aterosclerótica , Prolil Hidroxilases/genética , Animais , Aorta/patologia , Doenças da Aorta/enzimologia , Doenças da Aorta/genética , Doenças da Aorta/patologia , Aterosclerose/enzimologia , Aterosclerose/genética , Aterosclerose/patologia , Autoanticorpos/sangue , Dieta Hiperlipídica , Modelos Animais de Doenças , Lipase Lipoproteica/metabolismo , Lipoproteínas LDL/imunologia , Lipoproteínas LDL/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Knockout , Receptores de LDL/genética , Receptores de LDL/metabolismo , Transcriptoma , Triglicerídeos/sangueRESUMO
. COL18A1 gene mutations have been associated with Knobloch syndrome, which is characterized by ocular and brain abnormalities. Here we report a 4.5 years-old male child with autism and two novel COL18A1 mutations (NM_030582.4: c.1883_1891dup and c.1787C>T). Hypermetropic astigmatism, but not brain migration disorders, was observed. However, an asymmetric pattern of cerebellar perfusion and a smaller arcuate fascicle were found. Low levels of collagen XVIII were also observed in the patient´s serum. Thus, biallelic loss-of-function mutations in COL18A1 may be a new cause of autism without the brain malformations typically reported in patients with Knobloch syndrome.
Assuntos
Colágeno Tipo XVIII , Endostatinas , Cerebelo , Pré-Escolar , Colágeno Tipo XVIII/genética , Encefalocele , Endostatinas/genética , Humanos , Masculino , Mutação , Neuroimagem , Degeneração Retiniana , Descolamento Retiniano/congênitoRESUMO
BACKGROUND: The reported prevalence of Alport syndrome varies from one in 5000 to one in 53,000 individuals. This study estimated the frequencies of predicted pathogenic COL4A3-COL4A5 variants in sequencing databases of populations without known kidney disease. METHODS: Predicted pathogenic variants were identified using filtering steps based on the ACMG/AMP criteria, which considered collagen IV α3-α5 position 1 Gly to be critical domains. The population frequencies of predicted pathogenic COL4A3-COL4A5 variants were then determined per mean number of sequenced alleles. Population frequencies for compound heterozygous and digenic combinations were calculated from the results for heterozygous variants. RESULTS: COL4A3-COL4A5 variants resulting in position 1 Gly substitutions were confirmed to be associated with hematuria (for each, P<0.001). Predicted pathogenic COL4A5 variants were found in at least one in 2320 individuals. p.(Gly624Asp) represented nearly half (16 of 33, 48%) of the variants in Europeans. Most COL4A5 variants (54 of 59, 92%) had a biochemical feature that potentially mitigated the clinical effect. The predicted pathogenic heterozygous COL4A3 and COL4A4 variants affected one in 106 of the population, consistent with the finding of thin basement membrane nephropathy in normal donor kidney biopsy specimens. Predicted pathogenic compound heterozygous variants occurred in one in 88,866 individuals, and digenic variants in at least one in 44,793. CONCLUSIONS: The population frequencies for Alport syndrome are suggested by the frequencies of predicted pathogenic COL4A3-COL4A5 variants, but must be adjusted for the disease penetrance of individual variants and for the likelihood of already diagnosed disease and non-Gly substitutions. Disease penetrance may depend on other genetic and environmental factors.
Assuntos
Autoantígenos/genética , Colágeno Tipo IV/genética , Mutação/genética , Nefrite Hereditária/epidemiologia , Nefrite Hereditária/genética , Bases de Dados Genéticas , Feminino , Humanos , Masculino , Nefrite Hereditária/diagnóstico , Penetrância , PrevalênciaRESUMO
Yes-associated protein 1 (YAP1) is a transcriptional co-activator downstream of Hippo pathway. The pathway exerts crucial roles in organogenesis and its dysregulation is associated with the spreading of different cancer types. YAP1 gene encodes for multiple protein isoforms, whose specific functions are not well defined. We demonstrate the splicing of isoform-specific mRNAs is controlled in a stage- and tissue-specific fashion. We designed expression vectors encoding for the most-represented isoforms of YAP1 with either one or two WW domains and studied their specific signaling activities in YAP1 knock-out cell lines. YAP1 isoforms display both common and unique functions and activate distinct transcriptional programs, as the result of their unique protein interactomes. By generating TEAD-based transcriptional reporter cell lines, we demonstrate individual YAP1 isoforms display unique effects on cell proliferation and differentiation. Finally, we illustrate the complexity of the regulation of Hippo-YAP1 effector in physiological and in pathological conditions of the heart.
Assuntos
Proteínas de Ciclo Celular , Isoformas de RNA , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Sinalização YAPRESUMO
The extracellular matrix (ECM) is ubiquitously involved in neoplastic transformation, tumour growth and metastatic dissemination, and the interplay between tumour and stromal cells and the ECM is now considered crucial for the formation of a tumour-supporting microenvironment. The 28 different collagens (Col) form a major ECM protein family and display extraordinary functional diversity in tissue homeostasis as well as in pathological conditions, with functions ranging from structural support for tissues to regulatory binding activities and storage of biologically active cryptic domains releasable through ECM proteolysis. Two subfamilies of collagens, namely the plasma membrane-associated collagens with interrupted triple-helices (MACITs, including ColXIII, ColXXIII and ColXXV) and the basement membrane-associated collagens with multiple triple-helix domains with interruptions (multiplexins, including ColXV and ColXVIII), have highly interesting regulatory functions in tissue and organ development, as well as in various diseases, including cancer. An increasing, albeit yet sparse, data suggest that these collagens play crucial roles in conveying regulatory signals from the extracellular space to cells. We summarize here the current knowledge about MACITs and multiplexins as regulators of stemness and oncogenic processes, as well as their roles in influencing cell fate decisions in healthy and cancerous tissues. In addition, we present a bioinformatic analysis of the impacts of MACITs and multiplexins transcript levels on the prognosis of patients representing a wide array of malignant diseases, to aid future diagnostic and therapeutic efforts.
Assuntos
Membrana Celular/metabolismo , Neoplasias/metabolismo , Colágenos não Fibrilares/metabolismo , Células-Tronco/metabolismo , Animais , Suscetibilidade a Doenças , Matriz Extracelular/metabolismo , Regulação da Expressão Gênica , Humanos , Neoplasias/etiologia , Neoplasias/patologia , Proteólise , Nicho de Células-Tronco/genética , Relação Estrutura-Atividade , Microambiente TumoralRESUMO
KEY POINTS: Extracellular matrix is highly remodelled in obesity and associates with the development of metabolic disorders, such as insulin resistance. Previously, we have shown that the lack of specific collagen XVIII isoforms impairs adipocyte differentiation in mice. Here, we show that mice lacking the medium and long isoforms of collagen XVIII develop insulin resistance and glucose intolerance and show elevated serum triglycerides and fat accumulation in the liver. We report that collagen XVIII-deficient mice have increased heat production at low temperatures. These results reveal a new role for collagen XVIII in the regulation of glucose and lipid metabolism, and they expand the understanding of the development of metabolic disorders. ABSTRACT: Liver and adipose tissues play important roles in the regulation of systemic glucose and lipid metabolism. Extracellular matrix synthesis and remodelling are significantly altered in these tissues in obesity and type 2 diabetes. Collagen XVIII is a ubiquitous extracellular matrix component, and it occurs in three isoforms which differ in terms of molecular size, domain structure and tissue distribution. We recently showed that, in mice, the lack of collagen XVIII, and especially its medium and long isoforms, leads to reduced adiposity and dyslipidaemia. To address the metabolic consequences of these intriguing observations, we assessed whole-body glucose homeostasis in mice challenged with a high-fat diet and in normal physiological conditions. We observed that, in the high caloric diet, the overall adiposity was decreased by 30%, serum triglyceride values were threefold higher and the steatotic area in liver was twofold larger in collagen XVIII knockout mice compared with controls. We demonstrated that mice lacking either all three collagen XVIII isoforms, or specifically, the medium and long isoforms develop insulin resistance and glucose intolerance. Furthermore, we found that ablation of collagen XVIII leads to increased heat production in low temperatures and to reduction of the high blood triglyceride levels of the knockout mice to the level of wild-type mice. Our data indicate that collagen XVIII plays a role in the regulation of glucose tolerance, insulin sensitivity and lipid homeostasis, principally through its ability to regulate the expansion of the adipose tissue. These findings advance the understanding of metabolic disorders.
Assuntos
Diabetes Mellitus Tipo 2 , Resistência à Insulina , Lipodistrofia , Tecido Adiposo/metabolismo , Animais , Colágeno Tipo XVIII/metabolismo , Diabetes Mellitus Tipo 2/metabolismo , Dieta Hiperlipídica , Glucose/metabolismo , Homeostase , Metabolismo dos Lipídeos , Lipodistrofia/metabolismo , Fígado/metabolismo , Camundongos , Camundongos KnockoutRESUMO
Osteosarcoma (OS) is the most common primary malignant bone tumor and mainly affects children and adolescents. The OS five-year survival rate remains very low. Thus, novel therapeutic protocols for the treatment of OS are needed. Several approaches targeting deregulated signaling pathways have been proposed. The antitumoral effects of polyphenols, which are naturally occurring compounds with potent antioxidant and anti-inflammatory activity, have been investigated in different tumors. Gossypol, which is a natural polyphenolic aldehyde isolated from the seeds of the cotton plant, has been shown to exert antitumoral activity in leukemia and lymphoma and in breast, head and neck, colon and prostate cancers. Therefore, in this study, we evaluated the effect of AT-101, which is the (-) enantiomer and more active form of gossypol, on the growth of human and murine OS cells in vitro and in vivo. Several clinical trials employing AT-101 have been performed, and some clinical trials are ongoing. Our results showed for the first time that AT-101 significantly inhibits OS cell growth in a dose- and time-dependent manner, inducing apoptosis and necrosis and partially activating autophagy. Our results demonstrated that AT-101 inhibits prosurvival signaling pathways depending on Akt, p38 MAPK and JNK. In addition, treatment with AT-101 increases the survival of OS-bearing mice. Overall, these results suggest that AT-101 is a candidate chemo-supportive molecule for the development of novel chemotherapeutic protocols for the treatment of OS.
Assuntos
Antineoplásicos/farmacologia , Neoplasias Ósseas/tratamento farmacológico , Gossipol/análogos & derivados , Osteossarcoma/tratamento farmacológico , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Animais , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Neoplasias Ósseas/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Gossipol/farmacologia , Humanos , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Osteossarcoma/metabolismo , Polifenóis/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
The expression and regulation of matrisome genes-the ensemble of extracellular matrix, ECM, ECM-associated proteins and regulators as well as cytokines, chemokines and growth factors-is of paramount importance for many biological processes and signals within the tumor microenvironment. The availability of large and diverse multi-omics data enables mapping and understanding of the regulatory circuitry governing the tumor matrisome to an unprecedented level, though such a volume of information requires robust approaches to data analysis and integration. In this study, we show that combining Pan-Cancer expression data from The Cancer Genome Atlas (TCGA) with genomics, epigenomics and microenvironmental features from TCGA and other sources enables the identification of "landmark" matrisome genes and machine learning-based reconstruction of their regulatory networks in 74 clinical and molecular subtypes of human cancers and approx. 6700 patients. These results, enriched for prognostic genes and cross-validated markers at the protein level, unravel the role of genetic and epigenetic programs in governing the tumor matrisome and allow the prioritization of tumor-specific matrisome genes (and their regulators) for the development of novel therapeutic approaches.
Assuntos
Proteínas da Matriz Extracelular/metabolismo , Neoplasias/metabolismo , Transdução de Sinais , Microambiente Tumoral , Biomarcadores , Quimiocinas/metabolismo , Citocinas/metabolismo , Matriz Extracelular , Redes Reguladoras de Genes , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Aprendizado de Máquina , Neoplasias/genética , ProteômicaRESUMO
Collagen XVIII (ColXVIII) is a non-fibrillar collagen and proteoglycan that exists in three isoforms: short, medium and long. The medium and long isoforms contain a unique N-terminal domain of unknown function, DUF959, and our sequence-based secondary structure predictions indicated that DUF959 could be an intrinsically disordered domain. Recombinant DUF959 produced in mammalian cells consisted of â¼50% glycans and had a molecular mass of 63â kDa. Circular dichroism spectroscopy confirmed the disordered character of DUF959, and static light scattering indicated a monomeric state for glycosylated DUF959 in solution. Small-angle X-ray scattering showed DUF959 to be a highly extended, flexible molecule with a maximum dimension of â¼23â nm. Glycosidase treatment demonstrated considerable amounts of O-glycosylation, and expression of DUF959 in HEK293 SimpleCells capable of synthesizing only truncated O-glycans confirmed the presence of N-acetylgalactosamine-type O-glycans. The DUF959 sequence is characterized by numerous Ser and Thr residues, and this accounts for the finding that half of the recombinant protein consists of glycans. Thus, the medium and long ColXVIII isoforms contain at their extreme N-terminus a disordered, elongated and highly O-glycosylated mucin-like domain that is not found in other collagens, and we suggest naming it the Mucin-like domain in ColXVIII (MUCL-C18). As intrinsically disordered regions and their post-translational modifications are often involved in protein interactions, our findings may point towards a role of the flexible mucin-like domain of ColXVIII as an interaction hub affecting cell signaling. Moreover, the MUCL-C18 may also serve as a lubricant at cell-extracellular matrix interfaces.
Assuntos
Colágeno Tipo XVIII/química , Colágeno Tipo XVIII/metabolismo , Domínios Proteicos , Estrutura Secundária de Proteína , Sequência de Aminoácidos , Animais , Sítios de Ligação/genética , Colágeno Tipo XVIII/genética , Glicosilação , Células HEK293 , Humanos , Camundongos , Polissacarídeos/química , Polissacarídeos/metabolismo , Isoformas de Proteínas/química , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Espalhamento a Baixo Ângulo , Homologia de Sequência de Aminoácidos , Difração de Raios XRESUMO
Polyphenols are natural antioxidant compounds ubiquitously found in plants and, thus, ever present in human nutrition (tea, wine, chocolate, fruits and vegetables are typical examples of polyphenol-rich foods). Widespread evidence indicate that polyphenols exert strong antioxidant, anti-inflammatory, anti-microbial and anti-cancer activities, and thus, they are generally regarded to as all-purpose beneficial nutraceuticals or supplements whose use can only have a positive influence on the body. A closer look to the large body of results of years of investigations, however, present a more complex scenario where polyphenols exert different and, sometimes, paradoxical effects depending on dose, target system and cell type and the biological status of the target cell. Particularly, the immunomodulatory potential of polyphenols presents two opposite faces to researchers trying to evaluate their usability in future cancer therapies: on one hand, these compounds could be beneficial suppressors of peri-tumoral inflammation that fuels cancer growth. On the other hand, they might suppress immunotherapeutic approaches and give rise to immunosuppressive cell clones that, in turn, would aid tumor growth and dissemination. In this review, we summarize knowledge of the immunomodulatory effects of polyphenols with a particular focus on cancer microenvironment and immunotherapy, highlighting conceptual pitfalls and delicate cell-specific effects in order to aid the design of future therapies involving polyphenols as chemoadjuvants.
Assuntos
Fatores Imunológicos/metabolismo , Polifenóis/metabolismo , Microambiente Tumoral/fisiologia , Animais , Humanos , Fatores Imunológicos/uso terapêutico , Imunoterapia , Inflamação/tratamento farmacológico , Inflamação/imunologia , Inflamação/metabolismo , Polifenóis/uso terapêutico , Microambiente Tumoral/genéticaRESUMO
In bone marrow (BM), hematopoietic elements are mingled with adipocytes (BM-A), which are the most abundant stromal component in the niche. BM-A progressively increase with aging, eventually occupying up to 50% of BM cavities. In this work, the role played by BM-A was explored by studying primary human BM-A isolated from hip surgery patients at the molecular level, through microarray analysis, and at the functional level, by assessing their relationship with primary human hematopoietic stem cells (HSC) by the long-term culture initiating cell (LTC-IC) assay. Findings demonstrated that BM-A are capable of supporting HSC survival in the LTC-IC assay, since after 5 weeks of co-culture, HSC were still able to proliferate and differentiate. Furthermore, critical molecules such as C-X-C motif chemokine 12 (CXCL12), interleukin (IL)-8, colony-stimulating factor 3 (CSF3), and leukaemia inhibitory factor (LIF), were expressed at similar levels in BM-A and in primary human BM mesenchymal stromal cells (BM-MSC), whereas IL-3 was higher in BM-A. Interestingly, BM-A displayed a different gene expression profile compared with subcutaneous adipose tissue adipocytes (AT-A) collected from abdominal surgery patients, especially in terms of regulation of lipid metabolism, stemness genes, and white-to-brown differentiation pathways. Accordingly, analysis of the gene pathways involved in hematopoiesis regulation showed that BM-A are more closely related to BM-MSC than to AT-A. The present data suggest that BM-A play a supporting role in the hematopoietic niche and directly sustain HSC survival.
Assuntos
Adipócitos/fisiologia , Células da Medula Óssea/fisiologia , Comunicação Celular , Células-Tronco Hematopoéticas/fisiologia , Adipócitos/metabolismo , Idoso , Idoso de 80 Anos ou mais , Células da Medula Óssea/metabolismo , Proliferação de Células , Sobrevivência Celular , Células Cultivadas , Quimiocina CXCL12/metabolismo , Técnicas de Cocultura , Fatores Estimuladores de Colônias/metabolismo , Feminino , Hematopoese , Células-Tronco Hematopoéticas/metabolismo , Humanos , Interleucina-8/metabolismo , Fator Inibidor de Leucemia/metabolismo , Masculino , Pessoa de Meia-Idade , Fenótipo , Transdução de Sinais , Nicho de Células-Tronco , Gordura Subcutânea/citologia , Gordura Subcutânea/fisiologia , Fatores de Tempo , TranscriptomaRESUMO
White adipocytes are plastic cells able to reversibly transdifferentiate into brown adipocytes and into epithelial glandular cells under physiologic stimuli in vivo. These plastic properties could be used in future for regenerative medicine, but are incompletely explored in their details. Here, we focused on plastic properties of human mature adipocytes (MA) combining gene expression profile through microarray analysis with morphologic data obtained by electron and time lapse microscopy. Primary MA showed the classic morphology and gene expression profile of functional mature adipocytes. Notably, despite their committed status, MA expressed high levels of reprogramming genes. MA from ceiling cultures underwent transdifferentiation toward fibroblast-like cells with a well-differentiated morphology and maintaining stem cell gene signatures. The main morphologic aspect of the transdifferentiation process was the secretion of large lipid droplets and the development of organelles necessary for exocrine secretion further supported the liposecretion process. Of note, electron microscope findings suggesting liposecretion phenomena were found also in explants of human fat and rarely in vivo in fat biopsies from obese patients. In conclusion, both MA and post-liposecretion adipocytes show a well-differentiated phenotype with stem cell properties in line with the extraordinary plasticity of adipocytes in vivo. J. Cell. Physiol. 232: 2887-2899, 2017. © 2016 Wiley Periodicals, Inc.
Assuntos
Adipócitos Marrons/metabolismo , Adipócitos Brancos/metabolismo , Adipogenia , Plasticidade Celular , Metabolismo dos Lipídeos , Células-Tronco Mesenquimais/metabolismo , Obesidade/metabolismo , Adipócitos Marrons/ultraestrutura , Adipócitos Brancos/ultraestrutura , Idoso , Idoso de 80 Anos ou mais , Linhagem da Célula , Forma Celular , Células Cultivadas , Reprogramação Celular , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica no Desenvolvimento , Marcadores Genéticos , Humanos , Gotículas Lipídicas/metabolismo , Células-Tronco Mesenquimais/ultraestrutura , Microscopia Confocal , Microscopia Eletrônica , Microscopia de Vídeo , Pessoa de Meia-Idade , Obesidade/patologia , Obesidade/fisiopatologia , Análise de Sequência com Séries de Oligonucleotídeos , Fenótipo , Fatores de Tempo , Imagem com Lapso de TempoRESUMO
Collagen XVIII is an evolutionary conserved ubiquitously expressed basement membrane proteoglycan produced in three isoforms via two promoters (P). Here, we assess the function of the N-terminal, domain of unknown function/frizzled-like sequences unique to medium/long collagen XVIII by creating P-specific null mice. P2-null mice, which only produce short collagen XVIII, developed reduced bulk-adiposity, hepatic steatosis, and hypertriglyceridemia. These abnormalities did not develop in P1-null mice, which produce medium/long collagen XVIII. White adipose tissue samples from P2-null mice contain larger reserves of a cell population enriched in early adipocyte progenitors; however, their embryonic fibroblasts had â¼ 50% lower adipocyte differentiation potential. Differentiating 3T3-L1 fibroblasts into mature adipocytes produced striking increases in P2 gene-products and dramatic falls in P1-transcribed mRNA, whereas Wnt3a-induced dedifferentiation of mature adipocytes produced reciprocal changes in P1 and P2 transcript levels. P2-derived gene-products containing frizzled-like sequences bound the potent adipogenic inhibitor, Wnt10b, in vitro. Previously, we have shown that these same sequences bind Wnt3a, inhibiting Wnt3a-mediated signaling. P2-transcript levels in visceral fat were positively correlated with serum free fatty acid levels, suggesting that collagen α1 (XVIII) expression contributes to regulation of adipose tissue metabolism in visceral obesity. Medium/long collagen XVIII is deposited in the Space of Disse, and interaction between hepatic apolipoprotein E and this proteoglycan is lost in P2-null mice. These results describe a previously unidentified extracellular matrix-directed mechanism contributing to the control of the multistep adipogenic program that determines the number of precursors committing to adipocyte differentiation, the maintenance of the differentiated state, and the physiological consequences of its impairment on ectopic fat deposition.
Assuntos
Adipócitos/metabolismo , Tecido Adiposo/metabolismo , Diferenciação Celular/fisiologia , Colágeno Tipo XVIII/biossíntese , Ácidos Graxos/metabolismo , Fibroblastos/metabolismo , Células 3T3-L1 , Adipócitos/citologia , Tecido Adiposo/citologia , Adiposidade/fisiologia , Animais , Colágeno Tipo XVIII/genética , Embrião de Mamíferos/citologia , Embrião de Mamíferos/metabolismo , Ácidos Graxos/genética , Fígado Gorduroso/genética , Fígado Gorduroso/metabolismo , Feminino , Fibroblastos/citologia , Humanos , Masculino , Camundongos , Camundongos Mutantes , Transcrição Gênica/fisiologiaRESUMO
The sirtuins (SIRTs; SIRT1-7) are a family of NAD(+)-dependent enzymes that dynamically regulate cellular physiology. Apart from SIRT1, the functions and regulatory mechanisms of the SIRTs are poorly defined. We explored regulation of the SIRT family by 2 energy metabolism-controlling factors: peroxisome proliferator-activated receptor γ coactivator 1-α (PGC-1α) and AMP-activated protein kinase (AMPK). Overexpression of PGC-1α in mouse primary hepatocytes increased SIRT5 mRNA expression 4-fold and also the protein in a peroxisome proliferator-activated receptor α (PPARα)- and estrogen-related receptor α (ERRα)-dependent manner. Furthermore, food withdrawal increased SIRT5 mRNA 1.3-fold in rat liver. Overexpression of AMPK in mouse hepatocytes increased expression of SIRT1, SIRT2, SIRT3, and SIRT6 <2-fold. In contrast, SIRT5 mRNA was down-regulated by 58%. The antidiabetes drug metformin (1 mM), an established AMPK activator, reduced the mouse SIRT5 protein level by 44% in cultured hepatocytes and by 31% in liver in vivo (300 mg/kg, 7 d). Metformin also induced hypersuccinylation of mitochondrial proteins. Moreover, SIRT5 overexpression increased ATP synthesis and oxygen consumption in HepG2 cells, but did not affect mitochondrial biogenesis. In summary, our results identified SIRT5 as a novel factor that controls mitochondrial function. Moreover, SIRT5 levels are regulated by PGC-1α and AMPK, which have opposite effects on its expression.-Buler, M., Aatsinki, S.-M., Izzi, V., Uusimaa, J., Hakkola, J. SIRT5 is under the control of PGC-1α and AMPK and is involved in regulation of mitochondrial energy metabolism.
Assuntos
Proteínas Quinases Ativadas por AMP/metabolismo , Metabolismo Energético/fisiologia , Mitocôndrias/metabolismo , PPAR alfa/metabolismo , Sirtuínas/metabolismo , Proteínas Quinases Ativadas por AMP/genética , Animais , Linhagem Celular Tumoral , Metabolismo Energético/genética , Células Hep G2 , Hepatócitos/metabolismo , Humanos , Fígado/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Mitocôndrias/genética , Mitocôndrias/fisiologia , PPAR alfa/genética , RNA Mensageiro/genética , Ratos , Ratos Wistar , Receptores de Estrogênio/genética , Receptores de Estrogênio/metabolismo , Sirtuínas/genética , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Receptor ERRalfa Relacionado ao EstrogênioRESUMO
Collagen biosynthesis requires several co- and post-translational modifications of lysine and proline residues to form structurally and functionally competent collagen molecules. Formation of 4-hydroxyproline (4Hyp) in Y-position prolines of the repetitive -X-Y-Gly- sequences provides thermal stability for the triple-helical collagen molecules. 4Hyp formation is catalyzed by a collagen prolyl 4-hydroxylase (C-P4H) family consisting of three isoenzymes. Here we identify specific roles for the two main C-P4H isoenzymes in collagen hydroxylation by a detailed 4Hyp analysis of type I and IV collagens derived from cell and tissue samples. Loss of C-P4H-I results in underhydroxylation of collagen where the affected prolines are not uniformly distributed, but mainly present in sites where the adjacent X-position amino acid has a positively charged or a polar uncharged side chain. In contrast, loss of C-P4H-II results in underhydroxylation of triplets where the X-position is occupied by a negatively charged amino acid glutamate or aspartate. Hydroxylation of these triplets was found to be important as loss of C-P4H-II alone resulted in reduced collagen melting temperature and altered assembly of collagen fibrils and basement membrane. The observed C-P4H isoenzyme differences in substrate specificity were explained by selective binding of the substrate to the active site resulting in distinct differences in Km and Vmax values. Furthermore, our results clearly show that the substrate proline selection is not dependent on the collagen type, but the main determinant is the X-position amino acid of the -X-Pro-Gly- triplet. Although our data clearly shows the necessity of both C-P4H-I and II for normal prolyl 4-hydroxylation and function of collagens, the mRNA expression of the isoenzymes with various procollagens was, surprisingly, not tightly coordinated, suggesting additional levels of control. In conclusion, this study provides a molecular level explanation for the need of multiple C-P4H isoenzymes to generate collagen molecules capable to assemble into intact extracellular matrix structures.