Your browser doesn't support javascript.
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 70
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
Ann N Y Acad Sci ; 1456(1): 109-121, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31596512

RESUMO

Gpr126 (Adgrg6), a member of the adhesion G protein-coupled receptor family, has been associated with a variety of human diseases. Yet, despite its clinical importance, the mechanisms regulating Gpr126 expression are poorly understood. Here, we aimed at identifying upstream regulatory mechanisms of Gpr126 expression utilizing the heart as model organ in which Gpr126 regulates trabeculation. Here, we focused on possible regulation of Gpr126 regulation by microRNAs, which have emerged as key players in regulating development, have a critical role in disease progression, and might serve as putative therapeutic targets. In silico analyses identified one conserved binding site in the 3' UTR of Gpr126 for microRNA 27a and 27b (miR-27a/b). In addition, miR-27a/b and Gpr126 expression were differentially expressed during rat heart development. A regulatory role of miR-27a/b in controlling Gpr126 expression was substantiated by reduced Gpr126 mRNA levels upon ectopic expression of miR-27a/b in HEK293T cells and miR-27b in zebrafish embryos. Regulation of Gpr126 expression by direct binding of miR-27a/b to the 3' UTR of Gpr126 was verified by luciferase reporter assays in HEK293T cells. Finally, the modulation of gpr126 expression in zebrafish by injection of either miR-27b or miR-27b inhibitor in single cell-stage embryos resulted in hypo- or hypertrabeculation, respectively. Collectively, the data indicate that Gpr126 expression is regulated by miR-27a/b.

2.
Sci Rep ; 9(1): 11875, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31417141

RESUMO

Non-professional phagocytosis by cancer cells has been described for decades. Recently, non-professional phagocytosis by normal tissue cells has been reported, which prompted us to take a closer look at this phenomenon. Non-professional phagocytosis was studied by staining cultured cells with live-cell staining dyes or by staining paraffin-embedded tissues by immunohistochemistry. Here, we report that each of 21 normal tissue cell lines from seven different organs was capable of phagocytosis, including ex vivo cell cultures examined before the 3rd passage as well as the primary and virus-transformed cell lines. We extended our analysis to an in vivo setting, and we found the occurrence of non-professional phagocytosis in healthy skin biopsies immediately after resection. Using dystrophin immunohistochemistry for membrane staining, human post-infarction myocardial tissue was assessed. We found prominent signs of non-professional phagocytosis at the transition zone of healthy and infarcted myocardia. Taken together, our findings suggest that non-professional phagocytosis is a general feature of normal tissue cells.

3.
Biomater Sci ; 7(9): 3906-3917, 2019 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-31322163

RESUMO

Cardiovascular diseases represent a major socio-economic burden. In recent years, considerable effort has been invested in optimizing cell delivery strategies to advance cell transplantation therapies to restore heart function for example after an infarct. A particular issue is that the implantation of cells using a non-electroconductive matrix potentially causes arrhythmia. Here, we demonstrate that our hydrazide-functionalized nanotubes-pericardial matrix-derived electroconductive biohybrid hydrogel provides a suitable environment for maturation of human-induced pluripotent stem cell (hiPSC)-derived cardiomyocytes. hiPSC-derived cardiomyocytes exhibited an improved contraction amplitude (>500%) on conductive hydrogels compared to cells cultured on Matrigel®. This was accompanied by increased cellular alignment, enhanced connexin 43 expression, and improved sarcomere organization suggesting maturation of the hiPSC-derived cardiomyocytes. Sarcomeric length of these cells increased from 1.3 to 1.7 µm. Moreover, 3D cell-laden engineered tissues exhibited enhanced calcium handling as well as positive response to external electrical and pharmaceutical stimulation. Collectively, our data indicate that our biohybrid hydrogels consisting of solubilized nanostructured pericardial matrix and electroconductive positively charged hydrazide-conjugated carbon nanotubes provide a promising material for stem cell-based cardiac tissue engineering.


Assuntos
Materiais Biocompatíveis/química , Hidrogéis/química , Células-Tronco Pluripotentes Induzidas/citologia , Miócitos Cardíacos/citologia , Nanotubos de Carbono/química , Pericárdio/química , Tecidos Suporte/química , Biomarcadores/metabolismo , Cálcio/metabolismo , Diferenciação Celular , Proliferação de Células , Sobrevivência Celular , Colágeno/química , Conexina 43/metabolismo , Combinação de Medicamentos , Condutividade Elétrica , Humanos , Laminina/química , Células-Tronco Mesenquimais/citologia , Tamanho da Partícula , Proteoglicanas/química
4.
J Mol Cell Cardiol ; 134: 69-73, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31301302

RESUMO

BACKGROUND: The majority of adult human, mouse and rat cardiomyocytes is not diploid mononucleated. Nevertheless, the current literature on heart regeneration based on cardiomyocyte proliferation focuses mainly on the proliferation capacity of diploid mononucleated cardiomyocytes, instead of the more abundant mononucleated polyploid or binucleated cardiomyocytes. Here, we aimed at a better understanding of the process of mitosis and cell division in postnatal binucleated cardiomyocytes. METHODS AND RESULTS: Postnatal rat binucleated cardiomyocytes were stimulated to re-enter the cell cycle either by fetal bovine serum or a combination of fibroblast growth factor 1 and p38 MAP kinase inhibitor. Phase-contrast videos revealed that binucleated cardiomyocytes form one metaphase plate and preferentially undergo afterwards cytokinesis failure. The maximum rate of cell division of video-recorded binucleated cardiomyocytes was around 6%. Immunofluorescence analyses of centriole number in mitotic binucleated cardiomyocytes revealed that these cells contain more than four centrioles, which can be paired as well as unpaired. In agreement with multiple and/or unpaired centrioles, multipolar spindle formation was observed in mitotic binucleated cardiomyocytes using fluorescence live imaging of tubulin-GFP. Multipoles were transient and resolved into pseudo-bipolar spindles both in case of cell division and cytokinesis failure. Notably, centrioles were in most cases unevenly distributed among daughter cells. CONCLUSIONS: Our results indicate that postnatal binucleated cardiomyocytes upon stimulation can enter mitosis, cope with their multiple and/or unpaired centrioles by forming pseudo-bipolar spindles, and divide.

5.
Ann N Y Acad Sci ; 1456(1): 5-25, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31168816

RESUMO

The adhesion class of G protein-coupled receptors (GPCRs) is the second largest family of GPCRs (33 members in humans). Adhesion GPCRs (aGPCRs) are defined by a large extracellular N-terminal region that is linked to a C-terminal seven transmembrane (7TM) domain via a GPCR-autoproteolysis inducing (GAIN) domain containing a GPCR proteolytic site (GPS). Most aGPCRs undergo autoproteolysis at the GPS motif, but the cleaved fragments stay closely associated, with the N-terminal fragment (NTF) bound to the 7TM of the C-terminal fragment (CTF). The NTFs of most aGPCRs contain domains known to be involved in cell-cell adhesion, while the CTFs are involved in classical G protein signaling, as well as other intracellular signaling. In this workshop report, we review the most recent findings on the biology, signaling mechanisms, and physiological functions of aGPCRs.

6.
Clin Sci (Lond) ; 133(11): 1229-1253, 2019 Jun 14.
Artigo em Inglês | MEDLINE | ID: mdl-31175264

RESUMO

One great achievement in medical practice is the reduction in acute mortality of myocardial infarction due to identifying risk factors, antiplatelet therapy, optimized hospitalization and acute percutaneous coronary intervention. Yet, the prevalence of heart failure is increasing presenting a major socio-economic burden. Thus, there is a great need for novel therapies that can reverse damage inflicted to the heart. In recent years, data have accumulated suggesting that induction of cardiomyocyte proliferation might be a future option for cardiac regeneration. Here, we review the relevant literature since September 2015 concluding that it remains a challenge to verify that a therapy induces indeed cardiomyocyte proliferation. Most importantly, it is unclear that the detected increase in cardiomyocyte cell cycle activity is required for an associated improved function. In addition, we review the literature regarding the evidence that binucleated and polyploid mononucleated cardiomyocytes can divide, and put this in context to other cell types. Our analysis shows that there is significant evidence that binucleated cardiomyocytes can divide. Yet, it remains elusive whether also polyploid mononucleated cardiomyocytes can divide, how efficient proliferation of binucleated cardiomyocytes can be induced, what mechanism regulates cell cycle progression in these cells, and what fate and physiological properties the daughter cells have. In summary, we propose to standardize and independently validate cardiac regeneration studies, encourage the field to study the proliferative potential of binucleated and polyploid mononucleated cardiomyocytes, and to determine whether induction of polyploidization can enhance cardiac function post-injury.

7.
Ann N Y Acad Sci ; 1456(1): 96-108, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31215653

RESUMO

GPR126 (ADGRG6) is an adhesion G protein-coupled receptor that plays an important role in a variety of tissues/organs, such as heart, sciatic nerve, cartilage, and ear. Moreover, GPR126 (ADGRG6) mutations are associated with human diseases, like adolescent idiopathic scoliosis, lung disease, bladder cancer, and intellectual disability. Despite its clinical importance, it remains elusive how GPR126 is activated and mediates signal transduction and what cellular processes depend on GPR126 signaling. Here, we generated a lacZ reporter mouse line to determine endogenous Gpr126 (Adgrg6) expression in a cell type-specific manner during embryonic development, at postnatal day 5 and in adult animals. Our results confirm Gpr126 expression data previously obtained utilizing antibodies and in situ hybridization in embryonic heart and sciatic nerve. In addition, we provide data with cellular resolution for previously described RT-PCR-based data, including lung and bladder. Moreover, new Gpr126-expressing tissues and cell types were identified, such as ureter and acinar secretory cells. Collectively, our data demonstrate that the newly generated lacZ reporter mouse is a suitable model to study Gpr126 expression during development and adulthood, provide detailed insight into Gpr126 expression at the cellular level, and reveal that all identified Gpr126-expressing cells are known to be exposed to mechanical stimuli.

8.
Sci Rep ; 9(1): 7219, 2019 May 10.
Artigo em Inglês | MEDLINE | ID: mdl-31076608

RESUMO

Cytomegalovirus is a worldwide-distributed human pathogen, which is the leading cause of congenital virus infection, affecting 0.5 to 2% of live births. To date, it is largely unclear which molecular mechanisms underlie the symptomatic outcomes. This is mainly due to species specificity and limited homology among cytomegalovirus genomes. As it is not possible to infect model organisms with human cytomegalovirus, the aim of this study was to develop a heterologous system allowing in the future the elucidation of the pathological role of individual viral proteins. As a model organism the zebrafish has been chosen due to its ease of manipulation and characterization as well as its large offspring. As cytomegalovirus model protein, pUL97 was characterized because it is multiply involved in virus-host interaction. Here, we show in zebrafish embryos, that (i) pUL97 can be expressed in zebrafish, (ii) increasing pUL97 expression levels quantitatively correlate with both minor and major pathological defects, (iii) pUL97 expression impairs cell cycle progression and induces cell death, (iv) active pUL97, but not an inactive mutant, induces excess mortality, and (v) co-administration of a pUL97 inhibitor reduces embryonic pathology. Collectively, these data indicate the suitability of zebrafish to elucidate the pathological role of human cytomegaloviral proteins.

9.
Cardiovasc Res ; 115(3): 488-500, 2019 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-30657875

RESUMO

Morbidity and mortality from ischaemic heart disease (IHD) and heart failure (HF) remain significant in Europe and are increasing worldwide. Patients with IHD or HF might benefit from novel therapeutic strategies, such as cell-based therapies. We recently discussed the therapeutic potential of cell-based therapies and provided recommendations on how to improve the therapeutic translation of these novel strategies for effective cardiac regeneration and repair. Despite major advances in optimizing these strategies with respect to cell source and delivery method, the clinical outcome of cell-based therapy remains unsatisfactory. Major obstacles are the low engraftment and survival rate of transplanted cells in the harmful microenvironment of the host tissue, and the paucity or even lack of endogenous cells with repair capacity. Therefore, new ways of delivering cells and their derivatives are required in order to empower cell-based cardiac repair and regeneration in patients with IHD or HF. Strategies using tissue engineering (TE) combine cells with matrix materials to enhance cell retention or cell delivery in the transplanted area, and have recently received much attention for this purpose. Here, we summarize knowledge on novel approaches emerging from the TE scenario. In particular, we will discuss how combinations of cell/bio-materials (e.g. hydrogels, cell sheets, prefabricated matrices, microspheres, and injectable matrices) combinations might enhance cell retention or cell delivery in the transplantation areas, thereby increase the success rate of cell therapies for IHD and HF. We will not focus on the use of classical engineering approaches, employing fully synthetic materials, because of their unsatisfactory material properties which render them not clinically applicable. The overall aim of this Position Paper from the ESC Working Group Cellular Biology of the Heart is to provide recommendations on how to proceed in research with these novel TE strategies combined with cell-based therapies to boost cardiac repair in the clinical settings of IHD and HF.

10.
Expert Opin Biol Ther ; 19(2): 105-118, 2019 02.
Artigo em Inglês | MEDLINE | ID: mdl-30570406

RESUMO

INTRODUCTION: Vascularization remains one of the greatest yet unmet challenges in tissue engineering. When engineered tissues are scaled up to therapeutically relevant dimensions, their demand of oxygen and nutrients can no longer be met by diffusion. Thus, there is a need for perfusable vascular structures. Hypoxia-inducible factors (HIF) act as transcriptional oxygen sensors and regulate a multitude of genes involved in adaptive processes to hypoxia, including angiogenesis. Thus, targeting HIFs is a promising strategy to induce vascularization of engineered tissues. AREAS COVERED: Here we review current vascularization strategies and summarize the present knowledge regarding activation of HIF signaling by ions, iron chelating agents, α-Ketoglutarate (αKG) analogues, and the lipid-lowering drug simvastatin to induce angiogenesis. Specifically, we focus on the incorporation of HIF-activating agents into biomaterials and scaffolds for controlled release. EXPERT OPINION: Vascularization of tissue constructs through activation of upstream regulators of angiogenesis offers advantages but also suffers from drawbacks. HIFs can induce a complete angiogenic program; however, this program appears to be too slow to vascularize larger constructs before cell death occurs. It is therefore crucial that HIF-activation is combined with cell protective strategies and prevascularization techniques to obtain fully vascularized, vital tissues of therapeutically relevant dimensions.

11.
Biochem J ; 475(18): 2955-2967, 2018 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-30120107

RESUMO

Interferon-gamma (IFN-γ) is a pleiotropic cytokine that exerts important functions in inflammation, infectious diseases, and cancer. The large GTPase human guanylate-binding protein 1 (GBP-1) is among the most strongly IFN-γ-induced cellular proteins. Previously, it has been shown that GBP-1 mediates manifold cellular responses to IFN-γ including the inhibition of proliferation, spreading, migration, and invasion and through this exerts anti-tumorigenic activity. However, the mechanisms of GBP-1 anti-tumorigenic activities remain poorly understood. Here, we elucidated the molecular mechanism of the human GBP-1-mediated suppression of proliferation by demonstrating for the first time a cross-talk between the anti-tumorigenic IFN-γ and Hippo pathways. The α9-helix of GBP-1 was found to be sufficient to inhibit proliferation. Protein-binding and molecular modeling studies revealed that the α9-helix binds to the DNA-binding domain of the Hippo signaling transcription factor TEA domain protein (TEAD) mediated by the 376VDHLFQK382 sequence at the N-terminus of the GBP-1-α9-helix. Mutation of this sequence resulted in abrogation of both TEAD interaction and suppression of proliferation. Further on, the interaction caused inhibition of TEAD transcriptional activity associated with the down-regulation of TEAD-target genes. In agreement with these results, IFN-γ treatment of the cells also impaired TEAD activity, and this effect was abrogated by siRNA-mediated inhibition of GBP-1 expression. Altogether, this demonstrated that the α9-helix is the proliferation inhibitory domain of GBP-1, which acts independent of the GTPase activity through the inhibition of the Hippo transcription factor TEAD in mediating the anti-proliferative cell response to IFN-γ.

12.
Int J Mol Sci ; 19(7)2018 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-29996502

RESUMO

In contrast to the general belief that regeneration is a rare event, mainly occurring in simple organisms, the ability of regeneration is widely distributed in the animal kingdom. Yet, the efficiency and extent of regeneration varies greatly. Humans can recover from blood loss as well as damage to tissues like bone and liver. Yet damage to the heart and brain cannot be reversed, resulting in scaring. Thus, there is a great interest in understanding the molecular mechanisms of naturally occurring regeneration and to apply this knowledge to repair human organs. During regeneration, injury-activated immune cells induce wound healing, extracellular matrix remodeling, migration, dedifferentiation and/or proliferation with subsequent differentiation of somatic or stem cells. An anti-inflammatory response stops the regenerative process, which ends with tissue remodeling to achieve the original functional state. Notably, many of these processes are associated with enhanced glycolysis. Therefore, peroxisome proliferator-activated receptor (PPAR) β/δ—which is known to be involved for example in lipid catabolism, glucose homeostasis, inflammation, survival, proliferation, differentiation, as well as mammalian regeneration of the skin, bone and liver—appears to be a promising target to promote mammalian regeneration. This review summarizes our current knowledge of PPARβ/δ in processes associated with wound healing and regeneration.


Assuntos
Metabolismo dos Lipídeos , PPAR delta/metabolismo , PPAR beta/metabolismo , Cicatrização , Animais , Diferenciação Celular , Glicólise , Humanos , Regeneração , Via de Sinalização Wnt
13.
J Vis Exp ; (134)2018 04 04.
Artigo em Inglês | MEDLINE | ID: mdl-29683458

RESUMO

Primary cells isolated from human carcinomas are valuable tools to identify pathogenic mechanisms contributing to disease development and progression. In particular, endothelial cells (EC) constituting the inner surface of vessels, directly participate in oxygen delivery, nutrient supply, and removal of waste products to and from tumors, and are thereby prominently involved in the constitution of the tumor microenvironment (TME). Tumor endothelial cells (TECs) can be used as cellular biosensors of the intratumoral microenvironment established by communication between tumor and stromal cells. TECs also serve as targets of therapy. Accordingly, in culture these cells allow studies on mechanisms of response or resistance to anti-angiogenic treatment. Recently, it was found that TECs isolated from human colorectal carcinoma (CRC) exhibit memory-like effects based on the specific TME they were derived from. Moreover, these TECs actively contribute to the establishment of a specific TME by the secretion of different factors. For example, TECs in a prognostically favorable Th1-TME secrete the anti-angiogenic tumor-suppressive factor secreted protein, acidic and rich in cysteine-like 1 (SPARCL1). SPARCL1 regulates vessel homeostasis and inhibits tumor cell proliferation and migration. Hence, cultures of pure, viable TECs isolated from human solid tumors are a valuable tool for functional studies on the role of the vascular system in tumorigenesis. Here, a new up-to-date protocol for the isolation of primary EC from the normal colon as well as CRC is described. The technique is based on mechanical and enzymatic tissue digestion, immunolabeling, and fluorescence activated cell sorting (FACS)-sorting of triple-positive cells (CD31, VE-cadherin, CD105). With this protocol, viable TEC or normal endothelial cell (NEC) cultures could be isolated from colon tissues with a success rate of 62.12% when subjected to FACS-sorting (41 pure EC cultures from 66 tissue samples). Accordingly, this protocol provides a robust approach to isolate human EC cultures from normal colon and CRC.


Assuntos
Técnicas de Cultura de Células/métodos , Colo/metabolismo , Neoplasias Colorretais/metabolismo , Fibroblastos/metabolismo , Neovascularização Patológica/patologia , Proliferação de Células , Protocolos Clínicos , Neoplasias Colorretais/patologia , Células Endoteliais/citologia , Humanos , Microambiente Tumoral
14.
Am J Hum Genet ; 102(3): 468-479, 2018 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-29429572

RESUMO

Variants affecting the function of different subunits of the BAF chromatin-remodelling complex lead to various neurodevelopmental syndromes, including Coffin-Siris syndrome. Furthermore, variants in proteins containing PHD fingers, motifs recognizing specific histone tail modifications, have been associated with several neurological and developmental-delay disorders. Here, we report eight heterozygous de novo variants (one frameshift, two splice site, and five missense) in the gene encoding the BAF complex subunit double plant homeodomain finger 2 (DPF2). Affected individuals share common clinical features described in individuals with Coffin-Siris syndrome, including coarse facial features, global developmental delay, intellectual disability, speech impairment, and hypoplasia of fingernails and toenails. All variants occur within the highly conserved PHD1 and PHD2 motifs. Moreover, missense variants are situated close to zinc binding sites and are predicted to disrupt these sites. Pull-down assays of recombinant proteins and histone peptides revealed that a subset of the identified missense variants abolish or impaire DPF2 binding to unmodified and modified H3 histone tails. These results suggest an impairment of PHD finger structural integrity and cohesion and most likely an aberrant recognition of histone modifications. Furthermore, the overexpression of these variants in HEK293 and COS7 cell lines was associated with the formation of nuclear aggregates and the recruitment of both wild-type DPF2 and BRG1 to these aggregates. Expression analysis of truncating variants found in the affected individuals indicated that the aberrant transcripts escape nonsense-mediated decay. Altogether, we provide compelling evidence that de novo variants in DPF2 cause Coffin-Siris syndrome and propose a dominant-negative mechanism of pathogenicity.

15.
Front Cell Dev Biol ; 6: 9, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29468160

RESUMO

Chronic kidney disease (CKD) represents the fastest growing pathology worldwide with a prevalence of >10% in many countries. In addition, kidney cancer represents 5% of all new diagnosed cancers. As currently no effective therapies exist to restore kidney function after CKD- as well as cancer-induced renal damage, it is important to elucidate new regulators of kidney development and disease as new therapeutic targets. G protein-coupled receptors (GPCRs) represent the most successful class of pharmaceutical targets. In recent years adhesion GPCRs (aGPCRs), the second largest GPCR family, gained significant attention as they are present on almost all mammalian cells, are associated to a plethora of diseases and regulate important cellular processes. aGPCRs regulate for example cell polarity, mitotic spindle orientation, cell migration, and cell aggregation; all processes that play important roles in kidney development and/or disease. Moreover, polycystin-1, a major regulator of kidney development and disease, contains a GAIN domain, which is otherwise only found in aGPCRs. In this review, we assess the potential of aGPCRs as therapeutic targets for kidney disease. For this purpose we have summarized the available literature and analyzed data from the databases The Human Protein Atlas, EURExpress, Nephroseq, FireBrowse, cBioPortal for Cancer Genomics and the National Cancer Institute Genomic Data Commons data portal (NCIGDC). Our data indicate that most aGPCRs are expressed in different spatio-temporal patterns during kidney development and that altered aGPCR expression is associated with a variety of kidney diseases including CKD, diabetic nephropathy, lupus nephritis as well as renal cell carcinoma. We conclude that aGPCRs present a promising new class of therapeutic targets and/or might be useful as diagnostic markers in kidney disease.

17.
Cell Cycle ; 16(20): 1853-1854, 2017 Oct 18.
Artigo em Inglês | MEDLINE | ID: mdl-28937871
18.
Sci Rep ; 7(1): 8362, 2017 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-28827644

RESUMO

After birth cardiomyocytes undergo terminal differentiation, characterized by binucleation and centrosome disassembly, rendering the heart unable to regenerate. Yet, it has been suggested that newborn mammals regenerate their hearts after apical resection by cardiomyocyte proliferation. Thus, we tested the hypothesis that apical resection either inhibits, delays, or reverses cardiomyocyte centrosome disassembly and binucleation. Our data show that apical resection rather transiently accelerates centrosome disassembly as well as the rate of binucleation. Consistent with the nearly 2-fold increased rate of binucleation there was a nearly 2-fold increase in the number of cardiomyocytes in mitosis indicating that the majority of injury-induced cardiomyocyte cell cycle activity results in binucleation, not proliferation. Concurrently, cardiomyocytes undergoing cytokinesis from embryonic hearts exhibited midbody formation consistent with successful abscission, whereas those from 3 day-old cardiomyocytes after apical resection exhibited midbody formation consistent with abscission failure. Lastly, injured hearts failed to fully regenerate as evidenced by persistent scarring and reduced wall motion. Collectively, these data suggest that should a regenerative program exist in the newborn mammalian heart, it is quickly curtailed by developmental mechanisms that render cardiomyocytes post-mitotic.

19.
Proc Natl Acad Sci U S A ; 114(30): 8029-8034, 2017 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-28698371

RESUMO

GAS2L3 is a recently identified cytoskeleton-associated protein that interacts with actin filaments and tubulin. The in vivo function of GAS2L3 in mammals remains unknown. Here, we show that mice deficient in GAS2L3 die shortly after birth because of heart failure. Mammalian cardiomyocytes lose the ability to proliferate shortly after birth, and further increase in cardiac mass is achieved by hypertrophy. The proliferation arrest of cardiomyocytes is accompanied by binucleation through incomplete cytokinesis. We observed that GAS2L3 deficiency leads to inhibition of cardiomyocyte proliferation and to cardiomyocyte hypertrophy during embryonic development. Cardiomyocyte-specific deletion of GAS2L3 confirmed that the phenotype results from the loss of GAS2L3 in cardiomyocytes. Cardiomyocytes from Gas2l3-deficient mice exhibit increased expression of a p53-transcriptional program including the cell cycle inhibitor p21. Furthermore, loss of GAS2L3 results in premature binucleation of cardiomyocytes accompanied by unresolved midbody structures. Together these results suggest that GAS2L3 plays a specific role in cardiomyocyte cytokinesis and proliferation during heart development.


Assuntos
Cardiomiopatia Dilatada/genética , Citocinese , Proteínas do Citoesqueleto/fisiologia , Miócitos Cardíacos/fisiologia , Animais , Cardiomiopatia Dilatada/patologia , Inibidor de Quinase Dependente de Ciclina p21/metabolismo , Citocinese/genética , Proteínas do Citoesqueleto/genética , Fibrose , Deleção de Genes , Regulação da Expressão Gênica , Camundongos , Camundongos Knockout , Miocárdio/patologia , Proteína Supressora de Tumor p53/metabolismo
20.
Cell Res ; 27(8): 1002-1019, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28621328

RESUMO

Zebrafish can efficiently regenerate their heart through cardiomyocyte proliferation. In contrast, mammalian cardiomyocytes stop proliferating shortly after birth, limiting the regenerative capacity of the postnatal mammalian heart. Therefore, if the endogenous potential of postnatal cardiomyocyte proliferation could be enhanced, it could offer a promising future therapy for heart failure patients. Here, we set out to systematically identify small molecules triggering postnatal cardiomyocyte proliferation. By screening chemical compound libraries utilizing a Fucci-based system for assessing cell cycle stages, we identified carbacyclin as an inducer of postnatal cardiomyocyte proliferation. In vitro, carbacyclin induced proliferation of neonatal and adult mononuclear rat cardiomyocytes via a peroxisome proliferator-activated receptor δ (PPARδ)/PDK1/p308Akt/GSK3ß/ß-catenin pathway. Inhibition of PPARδ reduced cardiomyocyte proliferation during zebrafish heart regeneration. Notably, inducible cardiomyocyte-specific overexpression of constitutively active PPARδ as well as treatment with PPARδ agonist after myocardial infarction in mice induced cell cycle progression in cardiomyocytes, reduced scarring, and improved cardiac function. Collectively, we established a cardiomyocyte proliferation screening system and present a new drugable target with promise for the treatment of cardiac pathologies caused by cardiomyocyte loss.


Assuntos
Cardiomiopatias/metabolismo , Proliferação de Células/efeitos dos fármacos , Epoprostenol/análogos & derivados , Miocárdio/metabolismo , Miócitos Cardíacos/metabolismo , PPAR delta/metabolismo , Transdução de Sinais/efeitos dos fármacos , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/embriologia , Animais , Cardiomiopatias/tratamento farmacológico , Cardiomiopatias/patologia , Epoprostenol/farmacologia , Miocárdio/patologia , Miócitos Cardíacos/patologia , Ratos , Ratos Sprague-Dawley
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA