Inside the cell最新文献

{"title":"In EXOG-depleted cardiomyocytes cell death is marked by a decreased mitochondrial reserve capacity of the electron transport chain","authors":"Wardit Tigchelaar,&nbsp;Anne Margreet De Jong,&nbsp;Wiek H. van Gilst,&nbsp;Rudolf A. De Boer,&nbsp;Herman H. W. Silljé","doi":"10.1002/icl3.1047","DOIUrl":"https://doi.org/10.1002/icl3.1047","url":null,"abstract":"<div>\u0000 <p>Depletion of mitochondrial endo/exonuclease G-like (EXOG) in cultured neonatal cardiomyocytes stimulates mitochondrial oxygen consumption rate (OCR) and induces hypertrophy via reactive oxygen species (ROS). Here, we show that neurohormonal stress triggers cell death in endo/exonuclease G-like-depleted cells, and this is marked by a decrease in mitochondrial reserve capacity. Neurohormonal stimulation with phenylephrine (PE) did not have an additive effect on the hypertrophic response induced by endo/exonuclease G-like depletion. Interestingly, PE-induced atrial natriuretic peptide (ANP) gene expression was completely abolished in endo/exonuclease G-like-depleted cells, suggesting a reverse signaling function of endo/exonuclease G-like. Endo/exonuclease G-like depletion initially resulted in increased mitochondrial OCR, but this declined upon PE stimulation. In particular, the reserve capacity of the mitochondrial respiratory chain and maximal respiration were the first indicators of perturbations in mitochondrial respiration, and these marked the subsequent decline in mitochondrial function. Although pathological stimulation accelerated these processes, prolonged EXOG depletion also resulted in a decline in mitochondrial function. At early stages of endo/exonuclease G-like depletion, mitochondrial ROS production was increased, but this did not affect mitochondrial DNA (mtDNA) integrity. After prolonged depletion, ROS levels returned to control values, despite hyperpolarization of the mitochondrial membrane. The mitochondrial dysfunction finally resulted in cell death, which appears to be mainly a form of necrosis. In conclusion, endo/exonuclease G-like plays an essential role in cardiomyocyte physiology. Loss of endo/exonuclease G-like results in diminished adaptation to pathological stress. The decline in maximal respiration and reserve capacity is the first sign of mitochondrial dysfunction that determines subsequent cell death.</p>\u0000 </div>","PeriodicalId":91499,"journal":{"name":"Inside the cell","volume":"1 2","pages":"134-143"},"PeriodicalIF":0.0,"publicationDate":"2016-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/icl3.1047","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137532308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Arf6 and the 5'phosphatase of synaptojanin 1 regulate autophagy in cone photoreceptors","authors":"Ashley A. George,&nbsp;Sara Hayden,&nbsp;Gail R. Stanton,&nbsp;Susan E. Brockerhoff","doi":"10.1002/icl3.1044","DOIUrl":"10.1002/icl3.1044","url":null,"abstract":"<div>\u0000 <p>Abnormalities in the ability of cells to properly degrade proteins have been identified in many neurodegenerative diseases. Recent work has implicated synaptojanin 1 (SynJ1) in Alzheimer's disease and Parkinson's disease, although the role of this polyphosphoinositide phosphatase in protein degradation has not been thoroughly described. Here, we dissected in vivo the role of SynJ1 in endolysosomal trafficking in zebrafish cone photoreceptors using a SynJ1-deficient zebrafish mutant, <i>nrc^a14</i>. We found that loss of SynJ1 leads to specific accumulation of late endosomes and autophagosomes early in photoreceptor development. An analysis of autophagic flux revealed that autophagosomes accumulate because of a defect in maturation. In addition we found an increase in vesicles that are highly enriched for PI(3)P, but negative for an early endosome marker in <i>nrc^a14</i> cones. A mutational analysis of SynJ1 enzymatic domains found that activity of the 5'phosphatase, but not the Sac1 domain, is required to rescue both aberrant late endosomes and autophagosomes. Finally, modulating activity of the PI(4,5)P₂ regulator, Arf6, rescued the disrupted trafficking pathways in <i>nrc^a14</i> cones. Our study describes a specific role for SynJ1 in autophagosomal and endosomal trafficking and provides evidence that PI(4,5)P₂ participates in autophagy in a neuronal cell type.</p>\u0000 </div>","PeriodicalId":91499,"journal":{"name":"Inside the cell","volume":"1 2","pages":"117-133"},"PeriodicalIF":0.0,"publicationDate":"2016-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/icl3.1044","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34352601","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"To clear, or not to clear (senescent cells)? That is the question","authors":"Amaia Lujambio","doi":"10.1002/icl3.1046","DOIUrl":"https://doi.org/10.1002/icl3.1046","url":null,"abstract":"<div>\u0000 <p>Cellular senescence is an anti-proliferative program that restricts the propagation of cells subjected to different kinds of stress. Cellular senescence was initially described as a cell-autonomous tumor suppressor mechanism that triggers an irreversible cell cycle arrest that prevents the proliferation of damaged cells at risk of neoplastic transformation. However, discoveries during the last decade have established that senescent cells can also impact the surrounding tissue microenvironment and the neighboring cells in a non-cell-autonomous manner. These non-cell-autonomous activities are, in part, mediated by the selective secretion of extracellular matrix degrading enzymes, cytokines, chemokines and immune modulators, which collectively constitute the senescence-associated secretory phenotype. One of the key functions of the senescence-associated secretory phenotype is to attract immune cells, which in turn can orchestrate the elimination of senescent cells. Interestingly, the clearance of senescent cells seems to be critical to dictate the net effects of cellular senescence. As a general rule, the successful elimination of senescent cells takes place in processes that are considered beneficial, such as tumor suppression, tissue remodeling and embryonic development, while the chronic accumulation of senescent cells leads to more detrimental consequences, namely, cancer and aging. Nevertheless, exceptions to this rule may exist. Now that cellular senescence is in the spotlight for both anti-cancer and anti-aging therapies, understanding the precise underpinnings of senescent cell removal will be essential to exploit cellular senescence to its full potential.</p>\u0000 </div>","PeriodicalId":91499,"journal":{"name":"Inside the cell","volume":"1 2","pages":"87-95"},"PeriodicalIF":0.0,"publicationDate":"2016-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/icl3.1046","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137831576","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Welcome to our first issue...","authors":"Marcos Malumbres,&nbsp;Andrew Moore","doi":"10.1002/icl3.1045","DOIUrl":"10.1002/icl3.1045","url":null,"abstract":"<p>A quick glance at the scientific advances reported in 2015 will suffice to lead most people to the conclusion that the study of cell function is among the most relevant areas of scientific endeavor today. Since Schleiden and Schwann proposed the cell theory in 1838, biology has changed dramatically and continues to develop at breathtaking speed. The recent advances in gene editing technologies and our understanding of cellular pluripotency suggest that research in cell biology will provide major biomedical breakthroughs in the near future.</p><p><i>Inside the Cell</i> was born as a joint effort between scientists and editorial teams to present these advances in an Open Access Forum. This will be possible thanks to the support of a dedicated editorial board with broad experience in different areas of cell research: from microorganisms to human cells and from biochemistry and cell culture to mathematics. Given the expansion of technologies used to study cell function, an important aim of the journal is to provide an integrative view of cellular organization and function. This will be achieved through a combination of primary research papers covering all areas of cell biological research with reviews and commentaries to discuss recent advances in a cellular context. The consequences of such studies for our understanding of human disease or the development of new therapeutic strategies is another area that we wish to represent, hence exemplifying the relevance of cell and molecular biology in today's society.</p><p>The first issue of <i>Inside the Cell</i> combines reviews discussing some of these recent advances and primary research on a variety of hot topics. In our first published article, Katherine Belov and collaborators discuss the amazing evolutionary immunobiology of transmissible cancers, a topic that by chance became even hotter during the manuscript's revision, with the identification of contagious clam leukemia. Although this area has not received much attention until recently, it will undoubtedly generate new ideas and concepts in cancer evolution and the competition between cancer cells and their environment. Hugh E. Montgomery and colleagues report a new connection between mitochondrial function and cellular metabolism, mediated by the uncoupling proteins. The link – originally identified in genetic studies in two different European populations and then validated in cellular and molecular studies – could explain why drugs for treating hypertension via antagonism of the renin–angiotensin systems also reduce risk of diabetes and metabolic syndrome. Carla V. Finkielstein and Daniel G.S. Capelluto describe the multiple functions of a scaffold protein, Disabled-2, involved in many different pathways in the cell. This protein functions in modulating cell–cell interactions as well as in endocytic pathways, and as a consequence, its deregulation results in a wide spectrum of physiological abnormalities in different cell types.</p><p>The las","PeriodicalId":91499,"journal":{"name":"Inside the cell","volume":"1 1","pages":"5-6"},"PeriodicalIF":0.0,"publicationDate":"2015-12-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/icl3.1045","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"51559840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The hypoxic microenvironment: A determinant of cancer stem cell evolution","authors":"Amancio Carnero,&nbsp;Matilde Lleonart","doi":"10.1002/icl3.1039","DOIUrl":"https://doi.org/10.1002/icl3.1039","url":null,"abstract":"<div>\u0000 <p>Tumors are often viewed as unique entities with specific behaviors. However, tumors are a mixture of differentially evolved subpopulations of cells in constant Darwinian evolution, selecting the fittest clone and allowing it to outgrow the rest. As in the natural environment, the niche defines the properties the fittest clones must possess. Therefore, there can be multiple fit clones because of the various microenvironments inside a single tumor. Hypoxia is considered to be a major feature of the tumor microenvironment and is a potential contributor to the cancer stem cell (CSC) phenotype and its enhanced tumorigenicity. The acidic microenvironment around hypoxic cells is accompanied by the activation of a subset of proteases that contribute to metastasis. Because of aberrant angiogenesis and the inaccessibility of their locations, hypoxic cells are less likely to accumulate therapeutic concentrations of chemotherapeutics that can lead to therapeutic resistance. Therefore, the targeting of the hypoxic CSC niche in combination with chemotherapy may provide a promising strategy for eradicating CSCs. In this review, we examine the cancer stem cell hypothesis and its relationship to the microenvironment, specifically to hypoxia and the subsequent metabolic switch and how they shape tumor behavior.</p>\u0000 </div>","PeriodicalId":91499,"journal":{"name":"Inside the cell","volume":"1 2","pages":"96-105"},"PeriodicalIF":0.0,"publicationDate":"2015-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/icl3.1039","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137803952","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"P-TEFb goes viral","authors":"Justyna Zaborowska,&nbsp;Nur F. Isa,&nbsp;Shona Murphy","doi":"10.1002/icl3.1037","DOIUrl":"10.1002/icl3.1037","url":null,"abstract":"<div>\u0000 <p>Positive transcription elongation factor b (P-TEFb), which comprises cyclin-dependent kinase 9 (CDK9) kinase and cyclin T subunits, is an essential kinase complex in human cells. Phosphorylation of the negative elongation factors by P-TEFb is required for productive elongation of transcription of protein-coding genes by RNA polymerase II (pol II). In addition, P-TEFb-mediated phosphorylation of the carboxyl-terminal domain (CTD) of the largest subunit of pol II mediates the recruitment of transcription and RNA processing factors during the transcription cycle. CDK9 also phosphorylates p53, a tumor suppressor that plays a central role in cellular responses to a range of stress factors. Many viral factors affect transcription by recruiting or modulating the activity of CDK9. In this review, we will focus on how the function of CDK9 is regulated by viral gene products. The central role of CDK9 in viral life cycles suggests that drugs targeting the interaction between viral products and P-TEFb could be effective anti-viral agents.</p>\u0000 </div>","PeriodicalId":91499,"journal":{"name":"Inside the cell","volume":"1 2","pages":"106-116"},"PeriodicalIF":0.0,"publicationDate":"2015-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/icl3.1037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"34655456","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The genome editing revolution: A CRISPR-Cas TALE off-target story","authors":"Stefano Stella,&nbsp;Guillermo Montoya","doi":"10.1002/icl3.1038","DOIUrl":"https://doi.org/10.1002/icl3.1038","url":null,"abstract":"<div>\u0000 <p>In the last 10 years, we have witnessed a blooming of targeted genome editing systems and applications. The area was revolutionized by the discovery and characterization of the transcription activator-like effector proteins, which are easier to engineer to target new DNA sequences than the previously available DNA binding templates, zinc fingers and meganucleases. Recently, the area experimented a quantum leap because of the introduction of the clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein (Cas) system (clustered regularly interspaced short palindromic sequence). This ribonucleoprotein complex protects bacteria from invading DNAs, and it was adapted to be used in genome editing. The CRISPR ribonucleic acid (RNA) molecule guides to the specific DNA site the Cas9 nuclease to cleave the DNA target. Two years and more than 1000 publications later, the CRISPR-Cas system has become the main tool for genome editing in many laboratories. Currently the targeted genome editing technology has been used in many fields and may be a possible approach for human gene therapy. Furthermore, it can also be used to modifying the genomes of model organisms for studying human pathways or to improve key organisms for biotechnological applications, such as plants, livestock genome as well as yeasts and bacterial strains.</p>\u0000 </div>","PeriodicalId":91499,"journal":{"name":"Inside the cell","volume":"1 1","pages":"7-16"},"PeriodicalIF":0.0,"publicationDate":"2015-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/icl3.1038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137885469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Cellular lifespan and senescence: a complex balance between multiple cellular pathways","authors":"David Dolivo,&nbsp;Sarah Hernandez,&nbsp;Tanja Dominko","doi":"10.1002/icl3.1036","DOIUrl":"https://doi.org/10.1002/icl3.1036","url":null,"abstract":"<div>\u0000 <p>The study of cellular senescence and proliferative lifespan is becoming increasingly important because of the promises of autologous cell therapy, the need for model systems for tissue disease and the implication of senescent cell phenotypes in organismal disease states such as sarcopenia, diabetes and various cancers, among others. Here, we explain the concepts of proliferative cellular lifespan and cellular senescence, and we present factors that have been shown to mediate cellular lifespan positively or negatively. We review much recent literature and present potential molecular mechanisms by which lifespan mediation occurs, drawing from the fields of telomere biology, metabolism, NAD⁺ and sirtuin biology, growth factor signaling and oxygen and antioxidants. We conclude that cellular lifespan and senescence are complex concepts that are governed by multiple independent and interdependent pathways, and that greater understanding of these pathways, their interactions and their convergence upon specific cellular phenotypes may lead to viable therapies for tissue regeneration and treatment of age-related pathologies, which are caused by or exacerbated by senescent cells in vivo.</p>\u0000 </div>","PeriodicalId":91499,"journal":{"name":"Inside the cell","volume":"1 1","pages":"36-47"},"PeriodicalIF":0.0,"publicationDate":"2015-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/icl3.1036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137487286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Mechanisms regulating phosphatase specificity and the removal of individual phosphorylation sites during mitotic exit","authors":"Samuel Rogers,&nbsp;Rachael McCloy,&nbsp;D Neil Watkins,&nbsp;Andrew Burgess","doi":"10.1002/icl3.1035","DOIUrl":"https://doi.org/10.1002/icl3.1035","url":null,"abstract":"<div>\u0000 <p>Entry into mitosis is driven by the activity of kinases, which phosphorylate over 7000 proteins on multiple sites. For cells to exit mitosis and segregate their genome correctly, these phosphorylations must be removed in a specific temporal order. This raises a critical and important question: how are specific phosphorylation sites on an individual protein removed? Traditionally, the temporal order of dephosphorylation was attributed to decreasing kinase activity. However, recent evidence in human cells has identified unique patterns of dephosphorylation during mammalian mitotic exit that cannot be fully explained by the loss of kinase activity. This suggests that specificity is determined in part by phosphatases. In this review, we explore how the physicochemical properties of an individual phosphosite and its surrounding amino acids can affect interactions with a phosphatase. These positive and negative interactions in turn help determine the specific pattern of dephosphorylation required for correct mitotic exit.</p>\u0000 </div>","PeriodicalId":91499,"journal":{"name":"Inside the cell","volume":"1 1","pages":"27-35"},"PeriodicalIF":0.0,"publicationDate":"2015-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/icl3.1035","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137706147","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Genetic depletion of Polo-like kinase 1 leads to embryonic lethality due to mitotic aberrancies","authors":"Paulina Wachowicz,&nbsp;Gonzalo Fernández-Miranda,&nbsp;Carlos Marugán,&nbsp;Beatriz Escobar,&nbsp;Guillermo de Cárcer","doi":"10.1002/icl3.1022","DOIUrl":"https://doi.org/10.1002/icl3.1022","url":null,"abstract":"<div>\u0000 <p>Polo-like kinase 1 (PLK1) is a serine/threonine kinase that plays multiple and essential roles during the cell division cycle. Its inhibition in cultured cells leads to severe mitotic aberrancies and cell death. Whereas previous reports suggested that Plk1 depletion in mice leads to a non-mitotic arrest in early embryos, we show here that the bi-allelic <i>Plk1</i> depletion in mice certainly results in embryonic lethality due to extensive mitotic aberrations at the morula stage, including multi- and mono-polar spindles, impaired chromosome segregation and cytokinesis failure. In addition, the conditional depletion of Plk1 during mid-gestation leads also to severe mitotic aberrancies. Our data also confirms that Plk1 is completely dispensable for mitotic entry in vivo. On the other hand, Plk1 haploinsufficient mice are viable, and Plk1-heterozygous fibroblasts do not harbor any cell cycle alterations. Plk1 is overexpressed in many human tumors, suggesting a therapeutic benefit of inhibiting Plk1, and specific small-molecule inhibitors for this kinase are now being evaluated in clinical trials. Therefore, the different Plk1 mouse models here presented are a valuable tool to reexamine the relevance of the mitotic kinase Plk1 during mammalian development and animal physiology.</p>\u0000 </div>","PeriodicalId":91499,"journal":{"name":"Inside the cell","volume":"1 1","pages":"59-69"},"PeriodicalIF":0.0,"publicationDate":"2015-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1002/icl3.1022","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"137539812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}