1
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Sung CYW, Li M, Jonjic S, Sanchez V, Britt WJ. Cytomegalovirus infection lengthens the cell cycle of granule cell precursors during postnatal cerebellar development. JCI Insight 2024; 9:e175525. [PMID: 38855871 PMCID: PMC11382886 DOI: 10.1172/jci.insight.175525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 04/23/2024] [Indexed: 06/11/2024] Open
Abstract
Human cytomegalovirus (HCMV) infection in infants infected in utero can lead to a variety of neurodevelopmental disorders. However, mechanisms underlying altered neurodevelopment in infected infants remain poorly understood. We have previously described a murine model of congenital HCMV infection in which murine CMV (MCMV) spreads hematogenously and establishes a focal infection in all regions of the brain of newborn mice, including the cerebellum. Infection resulted in disruption of cerebellar cortical development characterized by reduced cerebellar size and foliation. This disruption was associated with altered cell cycle progression of the granule cell precursors (GCPs), which are the progenitors that give rise to granule cells (GCs), the most abundant neurons in the cerebellum. In the current study, we have demonstrated that MCMV infection leads to prolonged GCP cell cycle, premature exit from the cell cycle, and reduced numbers of GCs resulting in cerebellar hypoplasia. Treatment with TNF-α neutralizing antibody partially normalized the cell cycle alterations of GCPs and altered cerebellar morphogenesis induced by MCMV infection. Collectively, our results argue that virus-induced inflammation altered the cell cycle of GCPs resulting in a reduced numbers of GCs and cerebellar cortical hypoplasia, thus providing a potential mechanism for altered neurodevelopment in fetuses infected with HCMV.
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Affiliation(s)
- Cathy Yea Won Sung
- Department of Microbiology, University of Alabama at Birmingham, School of Medicine, Birmingham, Alabama, USA
- Laboratory of Hearing Biology and Therapeutics, National Institute on Deafness and Other Communication Disorders (NIDCD), NIH, Bethesda, Maryland, USA
| | - Mao Li
- Department of Pediatrics, University of Alabama at Birmingham, School of Medicine, Birmingham, Alabama, USA
| | - Stipan Jonjic
- Department of Histology and Embryology and
- Center for Proteomics, Faculty of Medicine, University of Rijeka, Rijeka, Croatia
| | - Veronica Sanchez
- Department of Pediatrics, University of Alabama at Birmingham, School of Medicine, Birmingham, Alabama, USA
| | - William J Britt
- Department of Microbiology, University of Alabama at Birmingham, School of Medicine, Birmingham, Alabama, USA
- Department of Pediatrics, University of Alabama at Birmingham, School of Medicine, Birmingham, Alabama, USA
- Department of Neurobiology, University of Alabama at Birmingham, School of Medicine, Birmingham, Alabama, USA
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2
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Schwarz RI. A synthetic cell density signal can drive proliferation in chick embryonic tendon cells and tendon cells from a full size rooster can produce high levels of procollagen in cell culture. PeerJ 2022; 10:e14533. [PMID: 36530397 PMCID: PMC9753744 DOI: 10.7717/peerj.14533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2022] [Accepted: 11/16/2022] [Indexed: 12/14/2022] Open
Abstract
Cell density signaling drives tendon morphogenesis by regulating both procollagen production and cell proliferation. The signal is composed of a small, highly conserved protein (SNZR P) tightly bound to a tissue-specific, unique lipid (SNZR L). This allows the complex (SNZR PL) to bind to the membrane of the cell and locally diffuse over a radius of ~1 mm. The cell produces low levels of this signal but the binding to the membrane increases with the number of tendon cells in the local environment. In this article SNZR P was produced in E.coli and SNZR L was chemically synthesized. The two bind together when heated to 60 °C in the presence of Ca++ and Mg++ and the synthesized SNZR PL at ng/ml levels can replace serum. Adding SNZR PL to the medium was also tested on primary tendon cells from adult roosters. The older cells were in a maintenance state in vivo and in cell culture they proliferate more slowly than embryonic cells. Nevertheless, after reaching a moderately high cell density, they produced high levels of procollagen similar to the embryonic cells. This data was not expected from older cells but suggests that adult tendon cells can regenerate the tissue after injury when given the correct signals.
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Affiliation(s)
- Richard I. Schwarz
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States,SNZR LLC, Oakland, CA, USA
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3
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Rowton M, Perez-Cervantes C, Hur S, Jacobs-Li J, Lu E, Deng N, Guzzetta A, Hoffmann AD, Stocker M, Steimle JD, Lazarevic S, Oubaha S, Yang XH, Kim C, Yu S, Eckart H, Koska M, Hanson E, Chan SSK, Garry DJ, Kyba M, Basu A, Ikegami K, Pott S, Moskowitz IP. Hedgehog signaling activates a mammalian heterochronic gene regulatory network controlling differentiation timing across lineages. Dev Cell 2022; 57:2181-2203.e9. [PMID: 36108627 PMCID: PMC10506397 DOI: 10.1016/j.devcel.2022.08.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 06/24/2022] [Accepted: 08/22/2022] [Indexed: 11/18/2022]
Abstract
Many developmental signaling pathways have been implicated in lineage-specific differentiation; however, mechanisms that explicitly control differentiation timing remain poorly defined in mammals. We report that murine Hedgehog signaling is a heterochronic pathway that determines the timing of progenitor differentiation. Hedgehog activity was necessary to prevent premature differentiation of second heart field (SHF) cardiac progenitors in mouse embryos, and the Hedgehog transcription factor GLI1 was sufficient to delay differentiation of cardiac progenitors in vitro. GLI1 directly activated a de novo progenitor-specific network in vitro, akin to that of SHF progenitors in vivo, which prevented the onset of the cardiac differentiation program. A Hedgehog signaling-dependent active-to-repressive GLI transition functioned as a differentiation timer, restricting the progenitor network to the SHF. GLI1 expression was associated with progenitor status across germ layers, and it delayed the differentiation of neural progenitors in vitro, suggesting a broad role for Hedgehog signaling as a heterochronic pathway.
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Affiliation(s)
- Megan Rowton
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Carlos Perez-Cervantes
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Suzy Hur
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Jessica Jacobs-Li
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Emery Lu
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Nikita Deng
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Alexander Guzzetta
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Andrew D Hoffmann
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Matthew Stocker
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Jeffrey D Steimle
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Sonja Lazarevic
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Sophie Oubaha
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Xinan H Yang
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Chul Kim
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Shuhan Yu
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Heather Eckart
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Mervenaz Koska
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Erika Hanson
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Sunny S K Chan
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA; Department of Pediatrics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Daniel J Garry
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA; Department of Pediatrics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Michael Kyba
- Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA; Department of Pediatrics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Anindita Basu
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Kohta Ikegami
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Sebastian Pott
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA
| | - Ivan P Moskowitz
- Departments of Pediatrics, Pathology, Human Genetics, and Genetic Medicine, The University of Chicago, Chicago, IL, USA.
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4
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KarakÜlah G, Yandim C. Signature changes in the expressions of protein-coding genes, lncRNAs, and repeat elements in early and late cellular senescence. ACTA ACUST UNITED AC 2021; 44:356-370. [PMID: 33402863 PMCID: PMC7759191 DOI: 10.3906/biy-2005-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Accepted: 08/24/2020] [Indexed: 12/13/2022]
Abstract
Replicative cellular senescence is the main cause of aging. It is important to note that early senescence is linked to tissue regeneration, whereas late senescence is known to trigger a chronically inflammatory phenotype. Despite the presence of various genome-wide studies, there is a lack of information on distinguishing early and late senescent phenotypes at the transcriptome level. Particularly, the changes in the noncoding RNA portion of the aging cell have not been fully elucidated. By utilising RNA sequencing data of fibroblasts, hereby, we are not only reporting changes in gene expression profiles and relevant biological processes in the early and late senescent phenotypes but also presenting significant differences in the expressions of many unravelled long noncoding RNAs (lncRNAs) and transcripts arisen from repetitive DNA. Our results indicate that, in addition to previously reported L1 elements, various LTR and DNA transposons, as well as members of the classical satellites including HSAT5 and α-satellites (ALR/Alpha), are expressed at higher levels in late senescence. Moreover, we revealed finer links between the expression levels of repeats with the genes located near them and known to be involved in cell cycle and senescence. Noncoding elements reported here provide a new perspective to be explored in further experimental studies.
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Affiliation(s)
- Gökhan KarakÜlah
- İzmir Biomedicine and Genome Center, İzmir Turkey.,İzmir International Biomedicine and Genome Institute, Dokuz Eylül University, İzmir Turkey
| | - Cihangir Yandim
- İzmir Biomedicine and Genome Center, İzmir Turkey.,Department of Genetics and Bioengineering, Faculty of Engineering, İzmir University of Economics, İzmir Turkey
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5
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Basu A, Mestres I, Sahu SK, Tiwari N, Khongwir B, Baumgart J, Singh A, Calegari F, Tiwari VK. Phf21b imprints the spatiotemporal epigenetic switch essential for neural stem cell differentiation. Genes Dev 2020; 34:1190-1209. [PMID: 32820037 PMCID: PMC7462064 DOI: 10.1101/gad.333906.119] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2019] [Accepted: 07/21/2020] [Indexed: 12/24/2022]
Abstract
Cerebral cortical development in mammals involves a highly complex and organized set of events including the transition of neural stem and progenitor cells (NSCs) from proliferative to differentiative divisions to generate neurons. Despite progress, the spatiotemporal regulation of this proliferation-differentiation switch during neurogenesis and the upstream epigenetic triggers remain poorly known. Here we report a cortex-specific PHD finger protein, Phf21b, which is highly expressed in the neurogenic phase of cortical development and gets induced as NSCs begin to differentiate. Depletion of Phf21b in vivo inhibited neuronal differentiation as cortical progenitors lacking Phf21b were retained in the proliferative zones and underwent faster cell cycles. Mechanistically, Phf21b targets the regulatory regions of cell cycle promoting genes by virtue of its high affinity for monomethylated H3K4. Subsequently, Phf21b recruits the lysine-specific demethylase Lsd1 and histone deacetylase Hdac2, resulting in the simultaneous removal of monomethylation from H3K4 and acetylation from H3K27, respectively. Intriguingly, mutations in the Phf21b locus associate with depression and mental retardation in humans. Taken together, these findings establish how a precisely timed spatiotemporal expression of Phf21b creates an epigenetic program that triggers neural stem cell differentiation during cortical development.
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Affiliation(s)
- Amitava Basu
- Institute of Molecular Biology, 55128 Mainz, Germany
| | - Iván Mestres
- Center for Regenerative Therapies Dresden (CRTD), School of Medicine, Technische Universität Dresden, 01307 Dresden, Germany
| | | | - Neha Tiwari
- Institute of Physiological Chemistry, University Medical Center Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
| | | | - Jan Baumgart
- Translational Animal Research Center (TARC), University Medical Centre, Johannes Gutenberg-University, 55131 Mainz, Germany
| | - Aditi Singh
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry, and Biomedical Science, Queens University Belfast, Belfast BT9 7BL, United Kingdom
| | - Federico Calegari
- Center for Regenerative Therapies Dresden (CRTD), School of Medicine, Technische Universität Dresden, 01307 Dresden, Germany
| | - Vijay K Tiwari
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry, and Biomedical Science, Queens University Belfast, Belfast BT9 7BL, United Kingdom
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6
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Zhao J, Tian Y, Zhang H, Qu L, Chen Y, Liu Q, Luo Y, Wu X. p53 Mutant p53 N236S Induces Neural Tube Defects in Female Embryos. Int J Biol Sci 2019; 15:2006-2015. [PMID: 31523200 PMCID: PMC6743294 DOI: 10.7150/ijbs.31451] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2018] [Accepted: 05/26/2019] [Indexed: 12/18/2022] Open
Abstract
The p53 is one of the most important tumor suppressors through surveillance of DNA damages and abnormal proliferation signals, and activation the cell cycle arrest and apoptosis in response to stress. However, the mutation of p53 is known to be oncogenic by both loss of function in inhibiting cell cycle progress and gain of function in promoting abnormal proliferation. In the present study, we have established a knock in mouse model containing an Asn-to-Ser substitution at p53 amino acid 236 by homologous recombination (p53N236S). Other than tumorigenesis phenotype, we found that p53S/S mice displayed female-specific phenotype of open neural tube in brain (exencephaly) and spinal cord (spina bifida). The occurrence rate for embryonic exencephaly is 68.5% in female p53S/S mice, which is much more than that of in p53-/- mice (37.1%) in the same genetic background. Further study found that p53N236S mutation increased neuronal proliferation and decreased neuronal differentiation and apoptosis. To rescue the phenotype, we inhibited cell proliferation by crossing Wrn-/- mice with p53S/S mice. The occurrence of NTDs in p53S/S Wrn-/- mice was 35.2%, thus suggesting that the inhibition of cell proliferation through a Wrn defect partially rescued the exencephaly phenotype in p53S/S mice. We also report that p53S decreased expression of UTX at mRNA and protein level via increasing Xist transcript, result in high female-specific H3K27me3 expression and repressed Mash1 transcription, which facilitating abnormal proliferation, differentiation, and apoptosis, result in the mis-regulation of neurodevelopment and neural tube defects (NTDs).
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Affiliation(s)
- Jinzhi Zhao
- Laboratory of Molecular Genetics of Aging & Tumor, Medical School, Kunming University of Science and Technology, Chenggong Campus, 727 South Jingming Road, Kunming, Yunnan 650500, China
| | - Yingbing Tian
- Laboratory of Molecular Genetics of Aging & Tumor, Medical School, Kunming University of Science and Technology, Chenggong Campus, 727 South Jingming Road, Kunming, Yunnan 650500, China
| | - Huihui Zhang
- Laboratory of Molecular Genetics of Aging & Tumor, Medical School, Kunming University of Science and Technology, Chenggong Campus, 727 South Jingming Road, Kunming, Yunnan 650500, China
| | - Lianhua Qu
- Laboratory of Molecular Genetics of Aging & Tumor, Medical School, Kunming University of Science and Technology, Chenggong Campus, 727 South Jingming Road, Kunming, Yunnan 650500, China
| | - Yu Chen
- Laboratory of Molecular Genetics of Aging & Tumor, Medical School, Kunming University of Science and Technology, Chenggong Campus, 727 South Jingming Road, Kunming, Yunnan 650500, China
| | - Qing Liu
- Laboratory of Molecular Genetics of Aging & Tumor, Medical School, Kunming University of Science and Technology, Chenggong Campus, 727 South Jingming Road, Kunming, Yunnan 650500, China
| | - Ying Luo
- Laboratory of Molecular Genetics of Aging & Tumor, Medical School, Kunming University of Science and Technology, Chenggong Campus, 727 South Jingming Road, Kunming, Yunnan 650500, China
| | - Xiaoming Wu
- Laboratory of Molecular Genetics of Aging & Tumor, Medical School, Kunming University of Science and Technology, Chenggong Campus, 727 South Jingming Road, Kunming, Yunnan 650500, China
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7
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Li L, Shi B, Chen J, Li C, Wang S, Wang Z, Zhu G. An E2F1/MiR-17-92 Negative Feedback Loop mediates proliferation of Mouse Palatal Mesenchymal Cells. Sci Rep 2017; 7:5148. [PMID: 28698574 PMCID: PMC5506009 DOI: 10.1038/s41598-017-05479-7] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 05/30/2017] [Indexed: 02/05/2023] Open
Abstract
Normal cell cycle progression and proliferation of palatal mesenchymal cells are important for palatal development. As targets of miR-17-92, E2F transcription factors family has been suggested to induce the transcription of miR-17-92 in several cell types. In the present study, we sought to investigate whether this negative feedback loop exists in mouse PMCs and what the function of this negative feedback loop would be in palatal mesenchymal cells. Using GeneMANIA, we revealed that the most important function of experimentally verified targets of miR-17-92 is cell cycle regulation. E2F1 and E2F3, but not E2F2, were extensively expressed in mouse palate. Over-expression of E2F1 significantly increased the expression of all the members of miR-17-92. After increased by E2F1, miR-17 and miR-20a may negatively target E2F1, and thereby prevent the cells from excessive proliferation. We suggest that the negative feedback loop between E2F1 and miR-17-92 may contribute to palatal development by regulating the proliferation and cell cycle of palatal mesenchymal cells.
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Affiliation(s)
- Ling Li
- Department of stomatology, Sichuan Cancer Hospital, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Sichuan, China.,Department of Head and Neck Surgery, Sichuan Cancer Hospital, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Sichuan, China
| | - Bing Shi
- State Key Laboratory of Oral Diseases, Department of Cleft lip and Palate Surgery, West China Hospital of Stomatology, Sichuan University, Sichuan, China
| | - Jin Chen
- Department of Head and Neck Surgery, Sichuan Cancer Hospital, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Sichuan, China
| | - Chunhua Li
- Department of Head and Neck Surgery, Sichuan Cancer Hospital, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Sichuan, China
| | - Shaoxin Wang
- Department of Head and Neck Surgery, Sichuan Cancer Hospital, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Sichuan, China
| | - Zhaohui Wang
- Department of Head and Neck Surgery, Sichuan Cancer Hospital, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Sichuan, China.
| | - Guiquan Zhu
- Department of stomatology, Sichuan Cancer Hospital, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Sichuan, China. .,Department of Head and Neck Surgery, Sichuan Cancer Hospital, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Sichuan, China.
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8
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Batsivari A, Rybtsov S, Souilhol C, Binagui-Casas A, Hills D, Zhao S, Travers P, Medvinsky A. Understanding Hematopoietic Stem Cell Development through Functional Correlation of Their Proliferative Status with the Intra-aortic Cluster Architecture. Stem Cell Reports 2017; 8:1549-1562. [PMID: 28479304 PMCID: PMC5469869 DOI: 10.1016/j.stemcr.2017.04.003] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 04/03/2017] [Accepted: 04/04/2017] [Indexed: 12/30/2022] Open
Abstract
During development, hematopoietic stem cells (HSCs) emerge in the aorta-gonad-mesonephros (AGM) region through a process of multi-step maturation and expansion. While proliferation of adult HSCs is implicated in the balance between self-renewal and differentiation, very little is known about the proliferation status of nascent HSCs in the AGM region. Using Fucci reporter mice that enable in vivo visualization of cell-cycle status, we detect increased proliferation during pre-HSC expansion followed by a slowing down of cycling once cells start to acquire a definitive HSC state, similar to fetal liver HSCs. We observe time-specific changes in intra-aortic hematopoietic clusters corresponding to HSC maturation stages. The proliferative architecture of the clusters is maintained in an orderly anatomical manner with slowly cycling cells at the base and more actively proliferating cells at the more apical part of the cluster, which correlates with c-KIT expression levels, thus providing an anatomical basis for the role of SCF in HSC maturation. Expansion of HSC precursors is accompanied by increased proliferation Final steps of HSC maturation are accompanied by decelerating proliferation Proliferative architecture of intra-aortic clusters is maintained during HSC development c-Kit expression levels correlate with the proliferative status of HSC precursors
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Affiliation(s)
- Antoniana Batsivari
- Institute for Stem Cell Research, Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, SCRM Bioquarter, 5 Little France Drive, Edinburgh EH16 4UU, UK
| | - Stanislav Rybtsov
- Institute for Stem Cell Research, Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, SCRM Bioquarter, 5 Little France Drive, Edinburgh EH16 4UU, UK
| | - Celine Souilhol
- Department of Infection, Immunity & Cardiovascular Disease, University of Sheffield, Sheffield S10 2RX, UK
| | - Anahi Binagui-Casas
- Institute for Stem Cell Research, Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, SCRM Bioquarter, 5 Little France Drive, Edinburgh EH16 4UU, UK
| | - David Hills
- Institute for Stem Cell Research, Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, SCRM Bioquarter, 5 Little France Drive, Edinburgh EH16 4UU, UK
| | - Suling Zhao
- Institute for Stem Cell Research, Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, SCRM Bioquarter, 5 Little France Drive, Edinburgh EH16 4UU, UK
| | - Paul Travers
- Institute for Stem Cell Research, Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, SCRM Bioquarter, 5 Little France Drive, Edinburgh EH16 4UU, UK
| | - Alexander Medvinsky
- Institute for Stem Cell Research, Medical Research Council Centre for Regenerative Medicine, University of Edinburgh, SCRM Bioquarter, 5 Little France Drive, Edinburgh EH16 4UU, UK.
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9
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Schwarz RI. Collagen I and the fibroblast: high protein expression requires a new paradigm of post-transcriptional, feedback regulation. Biochem Biophys Rep 2015; 3:38-44. [PMID: 26900604 PMCID: PMC4758689 DOI: 10.1016/j.bbrep.2015.07.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 07/10/2015] [Accepted: 07/13/2015] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Scaling protein production seems like a simple perturbation of transcriptional control. However, when embryonic tendon fibroblasts have to produce >50% procollagen and secrete it from the cell 4 times faster than the average protein, this taxes the cellular machinery and requires a fresh look at how the pathway is controlled. Ascorbate, a reducing agent, can stimulate procollagen production 6-fold. Procollagen mRNA levels goes up 6-fold but requires 3 days for the cell to accomplish this task. Secretion rates, the last cellular step in the process, also goes up 6-fold but this occurs in <1 h. What regulatory scheme is consistent with these properties? SCOPE OF THIS REVIEW This review focuses on fibroblasts that make high levels of procollagen (type I) and how they regulate the collagen pathway. Data from many different labs are relevant to this problem but it is hard to see the bigger picture from a large number of small studies. This review aims to consolidate this data into a coherent model and this requires solutions to some controversies and postulating potential mechanisms where the details are still missing. MAJOR CONCLUSIONS In high collagen producing cells, the pathway is controlled by post-transcriptional regulation. This requires feedback control between secretion and translation rates that is based on the helical structure of the procollagen molecule and additional tissue-specific modifications. GENERAL SIGNIFICANCE Transcriptional control does not scale well to high protein production with rapid regulation. New paradigms lead to better understanding of collagen diseases and tendon morphogenesis.
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Affiliation(s)
- Richard I. Schwarz
- Life Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, United States
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10
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Manuel MN, Mi D, Mason JO, Price DJ. Regulation of cerebral cortical neurogenesis by the Pax6 transcription factor. Front Cell Neurosci 2015; 9:70. [PMID: 25805971 PMCID: PMC4354436 DOI: 10.3389/fncel.2015.00070] [Citation(s) in RCA: 105] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Accepted: 02/18/2015] [Indexed: 12/19/2022] Open
Abstract
Understanding brain development remains a major challenge at the heart of understanding what makes us human. The neocortex, in evolutionary terms the newest part of the cerebral cortex, is the seat of higher cognitive functions. Its normal development requires the production, positioning, and appropriate interconnection of very large numbers of both excitatory and inhibitory neurons. Pax6 is one of a relatively small group of transcription factors that exert high-level control of cortical development, and whose mutation or deletion from developing embryos causes major brain defects and a wide range of neurodevelopmental disorders. Pax6 is very highly conserved between primate and non-primate species, is expressed in a gradient throughout the developing cortex and is essential for normal corticogenesis. Our understanding of Pax6’s functions and the cellular processes that it regulates during mammalian cortical development has significantly advanced in the last decade, owing to the combined application of genetic and biochemical analyses. Here, we review the functional importance of Pax6 in regulating cortical progenitor proliferation, neurogenesis, and formation of cortical layers and highlight important differences between rodents and primates. We also review the pathological effects of PAX6 mutations in human neurodevelopmental disorders. We discuss some aspects of Pax6’s molecular actions including its own complex transcriptional regulation, the distinct molecular functions of its splice variants and some of Pax6’s known direct targets which mediate its actions during cortical development.
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Affiliation(s)
- Martine N Manuel
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh UK
| | - Da Mi
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh UK
| | - John O Mason
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh UK
| | - David J Price
- Centre for Integrative Physiology, The University of Edinburgh, Edinburgh UK
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11
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Schindler AJ, Sherwood DR. Morphogenesis of the caenorhabditis elegans vulva. WILEY INTERDISCIPLINARY REVIEWS-DEVELOPMENTAL BIOLOGY 2014; 2:75-95. [PMID: 23418408 DOI: 10.1002/wdev.87] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Understanding how cells move, change shape, and alter cellular behaviors to form organs, a process termed morphogenesis, is one of the great challenges of developmental biology. Formation of the Caenorhabditis elegans vulva is a powerful, simple, and experimentally accessible model for elucidating how morphogenetic processes produce an organ. In the first step of vulval development, three epithelial precursor cells divide and differentiate to generate 22 cells of 7 different vulval subtypes. The 22 vulval cells then rearrange from a linear array into a tube, with each of the seven cell types undergoing characteristic morphogenetic behaviors that construct the vulva. Vulval morphogenesis entails many of the same cellular activities that underlie organogenesis and tissue formation across species, including invagination, lumen formation, oriented cell divisions, cell–cell adhesion, cell migration, cell fusion, extracellular matrix remodeling, and cell invasion. Studies of vulval development have led to pioneering discoveries in a number of these processes and are beginning to bridge the gap between the pathways that specify cells and their connections to morphogenetic behaviors. The simplicity of the vulva and the experimental tools available in C. elegans will continue to make vulval morphogenesis a powerful paradigm to further our understanding of the largely mysterious mechanisms that build tissues and organs.
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Petzold CJ, Schwarz RI. Cells determine cell density using a small protein bound to a unique tissue-specific phospholipid. PeerJ 2013; 1:e192. [PMID: 24244914 PMCID: PMC3817597 DOI: 10.7717/peerj.192] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Accepted: 10/08/2013] [Indexed: 02/01/2023] Open
Abstract
Cell density is the critical parameter controlling tendon morphogenesis. Knowing its neighbors allows a cell to regulate correctly its proliferation and collagen production. A missing link to understanding this process is a molecular description of the sensing mechanism. Previously, this mechanism was shown in cell culture to rely on a diffusible factor (SNZR [sensor]) with an affinity for the cell layer. This led to purifying conditioned medium over 4 columns and analyzing the final column fractions for band intensity on SDS gels versus biological activity - a 16 kD band strongly correlated between assays. N-terminal sequencing - EPLAVVDL - identified a large gene (424 AA), extremely conserved between chicken and human. In this paper we probe whether this is the correct gene. Can the predicted large protein be cleaved to a smaller protein? EPLAVVDL occurs towards the C-terminus and cleavage would create a small 94 AA protein. This protein would run at ∼10 kD, so what modifications or cofactor binding accounts for its running at 16 kD on SDS gels? This protein has no prominent hydrophobic regions, so can it be secreted? To validate its role, the chicken cDNA for this gene was tagged with myc and his and transfected into a human osteosarcoma cell line (U2OS). U2OS cells expressed the gene but not passively: differentiating into structures resembling spongy bone and expressing alkaline phosphatase, an early bone marker. Intracellularly, two bands were observed by Western blotting: the full length protein and a smaller form (26 kD). Outside the cell, a small band (28 kD) was detected, although it was 40% larger than expected, as well as multiple larger bands. These larger forms could be converted to the predicted smaller protein (94 AA + tags) by changing salt concentrations and ultrafiltering - releasing a cofactor to the filtrate while leaving a protein factor in the retentate. Using specific degradative enzymes and mass spectrometry, the bone cofactor was identified as a lipid containing a ceramide phosphate, a single chained glycerol lipid and a linker. Tendon uses a different cofactor made up of two fatty acid chains linked directly to the phosphate yielding a molecule about half the size. Moreover, adding the tendon factor/cofactor to osteosarcoma cells causes them to stop growing, which is opposite to its role with tendon cells. Thus, the cofactor is cell type specific both in composition and in the triggered response. Further support of its proposed role came from frozen sections from 5 week old mice where an antibody to the factor stained strongly at the growing ends of the tendon as predicted. In conclusion, the molecule needed for cell density signaling is a small protein bound to a unique, tissue-specific phospholipid yielding a membrane associated but diffusible molecule. Signal transduction is postulated to occur by an increased ordering of the plasma membrane as the concentration of this protein/lipid increases with cell density.
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Affiliation(s)
- Christopher J Petzold
- Joint BioEnergy Institute, Lawrence Berkeley National Laboratory , Berkeley, CA , USA
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Kaposi's sarcoma-associated herpesvirus transactivator Rta induces cell cycle arrest in G0/G1 phase by stabilizing and promoting nuclear localization of p27kip. J Virol 2013; 87:13226-38. [PMID: 24067984 DOI: 10.1128/jvi.02540-13] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The Kaposi's sarcoma-associated herpesvirus (KSHV) immediate-early gene, replication, and transcription activator (K-Rta) is a key viral protein that serves as the master regulator for viral lytic replication. In this study, we investigated the role of K-Rta in cell cycle regulation and found that the expression of K-Rta in doxycycline (Dox)-inducible BJAB cells induced cell cycle arrest in G0/G1 phase. Western blot analysis of key cell cycle regulators revealed that K-Rta-mediated cell cycle arrest was associated with a decrease in cyclin A and phosphorylated Rb (pS807/pS811) protein levels, both markers of S phase progression, and an increase in protein levels for p27, a cyclin-dependent kinase inhibitor. Further, we found that K-Rta does not affect the transcription of p27 but regulates p27 at the posttranslational level by inhibiting its proteosomal degradation. Immunofluorescence staining and cell fractionation experiments revealed largely nuclear compartmentalization of p27 in K-Rta-expressing cells, demonstrating that K-Rta not only stabilizes p27 but also modulates its cellular localization. Finally, short hairpin RNA knockdown of p27 significantly abrogates cell cycle arrest in K-Rta-expressing cells, supporting its key role in K-Rta-mediated cell cycle arrest. Our findings are consistent with previous studies which showed that expression of immediate-early genes of several herpesviruses, including herpes simplex virus, Epstein-Barr virus, and cytomegalovirus, results in cell cycle arrest at the G0/G1 phase, possibly to avoid competition for resources needed for host cell replication during the S phase.
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Konorov SO, Schulze HG, Piret JM, Blades MW, Turner RFB. Label-Free Determination of the Cell Cycle Phase in Human Embryonic Stem Cells by Raman Microspectroscopy. Anal Chem 2013; 85:8996-9002. [DOI: 10.1021/ac400310b] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stanislav O. Konorov
- Michael Smith
Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, British Columbia, Canada, V6T 1Z4
- Department
of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada, V6T 1Z1
| | - H. Georg Schulze
- Michael Smith
Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, British Columbia, Canada, V6T 1Z4
| | - James M. Piret
- Michael Smith
Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, British Columbia, Canada, V6T 1Z4
- Department
of Chemical and Biological Engineering, The University of British Columbia, 2360 East Mall, Vancouver, British Columbia, Canada, V6T 1Z3
| | - Michael W. Blades
- Department
of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada, V6T 1Z1
| | - Robin F. B. Turner
- Michael Smith
Laboratories, The University of British Columbia, 2185 East Mall, Vancouver, British Columbia, Canada, V6T 1Z4
- Department
of Chemistry, The University of British Columbia, 2036 Main Mall, Vancouver, British Columbia, Canada, V6T 1Z1
- Department
of Electrical and Computer Engineering, The University of British Columbia, 2332 Main Mall, Vancouver, British Columbia, Canada, V6T 1Z4
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Janesick A, Abbey R, Chung C, Liu S, Taketani M, Blumberg B. ERF and ETV3L are retinoic acid-inducible repressors required for primary neurogenesis. Development 2013; 140:3095-106. [PMID: 23824578 DOI: 10.1242/dev.093716] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Cells in the developing neural tissue demonstrate an exquisite balance between proliferation and differentiation. Retinoic acid (RA) is required for neuronal differentiation by promoting expression of proneural and neurogenic genes. We show that RA acts early in the neurogenic pathway by inhibiting expression of neural progenitor markers Geminin and Foxd4l1, thereby promoting differentiation. Our screen for RA target genes in early Xenopus development identified Ets2 Repressor Factor (Erf) and the closely related ETS repressors Etv3 and Etv3-like (Etv3l). Erf and Etv3l are RA responsive and inhibit the action of ETS genes downstream of FGF signaling, placing them at the intersection of RA and growth factor signaling. We hypothesized that RA regulates primary neurogenesis by inducing Erf and Etv3l to antagonize proliferative signals. Loss-of-function analysis showed that Erf and Etv3l are required to inhibit proliferation of neural progenitors to allow differentiation, whereas overexpression of Erf led to an increase in the number of primary neurons. Therefore, these RA-induced ETS repressors are key components of the proliferation-differentiation switch during primary neurogenesis in vivo.
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Affiliation(s)
- Amanda Janesick
- Department of Developmental and Cell Biology, 2011 Biological Sciences 3, University of California, Irvine, CA 92697-2300, USA
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Wang G, Li Y, Wang XY, Han Z, Chuai M, Wang LJ, Ho Lee KK, Geng JG, Yang X. Slit/Robo1 signaling regulates neural tube development by balancing neuroepithelial cell proliferation and differentiation. Exp Cell Res 2013; 319:1083-93. [PMID: 23438940 DOI: 10.1016/j.yexcr.2013.02.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Revised: 02/05/2013] [Accepted: 02/08/2013] [Indexed: 12/27/2022]
Abstract
Formation of the neural tube is the morphological hallmark for development of the embryonic central nervous system (CNS). Therefore, neural tube development is a crucial step in the neurulation process. Slit/Robo signaling was initially identified as a chemo-repellent that regulated axon growth cone elongation, but its role in controlling neural tube development is currently unknown. To address this issue, we investigated Slit/Robo1 signaling in the development of chick neCollege of Life Sciences Biocentre, University of Dundee, Dundee DD1 5EH, UKural tube and transgenic mice over-expressing Slit2. We disrupted Slit/Robo1 signaling by injecting R5 monoclonal antibodies into HH10 neural tubes to block the Robo1 receptor. This inhibited the normal development of the ventral body curvature and caused the spinal cord to curl up into a S-shape. Next, Slit/Robo1 signaling on one half-side of the chick embryo neural tube was disturbed by electroporation in ovo. We found that the morphology of the neural tube was dramatically abnormal after we interfered with Slit/Robo1 signaling. Furthermore, we established that silencing Robo1 inhibited cell proliferation while over-expressing Robo1 enhanced cell proliferation. We also investigated the effects of altering Slit/Robo1 expression on Sonic Hedgehog (Shh) and Pax7 expression in the developing neural tube. We demonstrated that over-expressing Robo1 down-regulated Shh expression in the ventral neural tube and resulted in the production of fewer HNK-1(+) migrating neural crest cells (NCCs). In addition, Robo1 over-expression enhanced Pax7 expression in the dorsal neural tube and increased the number of Slug(+) pre-migratory NCCs. Conversely, silencing Robo1 expression resulted in an enhanced Shh expression and more HNK-1(+) migrating NCCs but reduced Pax7 expression and fewer Slug(+) pre-migratory NCCs were observed. In conclusion, we propose that Slit/Robo1 signaling is involved in regulating neural tube development by tightly coordinating cell proliferation and differentiation during neurulation.
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Affiliation(s)
- Guang Wang
- Key Laboratory for Regenerative Medicine of The Ministry of Education, Department of Histology and Embryology, School of Medicine, Jinan University, Guangzhou 510632, China
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