Browsing by Subject "Cell Lineage"

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Open Access
A Genetic Mosaic Screen Reveals Ecdysone-Responsive Genes Regulating Drosophila Oogenesis.
(G3 (Bethesda, Md.), 2016-08) Ables, Elizabeth T; Hwang, Grace H; Finger, Danielle S; Hinnant, Taylor D; Drummond-Barbosa, Daniela
Multiple aspects of Drosophila oogenesis, including germline stem cell activity, germ cell differentiation, and follicle survival, are regulated by the steroid hormone ecdysone. While the transcriptional targets of ecdysone signaling during development have been studied extensively, targets in the ovary remain largely unknown. Early studies of salivary gland polytene chromosomes led to a model in which ecdysone stimulates a hierarchical transcriptional cascade, wherein a core group of ecdysone-sensitive transcription factors induce tissue-specific responses by activating secondary branches of transcriptional targets. More recently, genome-wide approaches have identified hundreds of putative ecdysone-responsive targets. Determining whether these putative targets represent bona fide targets in vivo, however, requires that they be tested via traditional mutant analysis in a cell-type specific fashion. To investigate the molecular mechanisms whereby ecdysone signaling regulates oogenesis, we used genetic mosaic analysis to screen putative ecdysone-responsive genes for novel roles in the control of the earliest steps of oogenesis. We identified a cohort of genes required for stem cell maintenance, stem and progenitor cell proliferation, and follicle encapsulation, growth, and survival. These genes encode transcription factors, chromatin modulators, and factors required for RNA transport, stability, and ribosome biogenesis, suggesting that ecdysone might control a wide range of molecular processes during oogenesis. Our results suggest that, although ecdysone target genes are known to have cell type-specific roles, many ecdysone response genes that control larval or pupal cell types at developmental transitions are used reiteratively in the adult ovary. These results provide novel insights into the molecular mechanisms by which ecdysone signaling controls oogenesis, laying new ground for future studies.
Open Access
A miR-34a-Numb Feedforward Loop Triggered by Inflammation Regulates Asymmetric Stem Cell Division in Intestine and Colon Cancer.
(Cell Stem Cell, 2016-02-04) Bu, Pengcheng; Wang, Lihua; Chen, Kai-Yuan; Srinivasan, Tara; Murthy, Preetish Kadur Lakshminarasimha; Tung, Kuei-Ling; Varanko, Anastasia Kristine; Chen, Huanhuan Joyce; Ai, Yiwei; King, Sarah; Lipkin, Steven M; Shen, Xiling
Emerging evidence suggests that microRNAs can initiate asymmetric division, but whether microRNA and protein cell fate determinants coordinate with each other remains unclear. Here, we show that miR-34a directly suppresses Numb in early-stage colon cancer stem cells (CCSCs), forming an incoherent feedforward loop (IFFL) targeting Notch to separate stem and non-stem cell fates robustly. Perturbation of the IFFL leads to a new intermediate cell population with plastic and ambiguous identity. Lgr5+ mouse intestinal/colon stem cells (ISCs) predominantly undergo symmetric division but turn on asymmetric division to curb the number of ISCs when proinflammatory response causes excessive proliferation. Deletion of miR-34a inhibits asymmetric division and exacerbates Lgr5+ ISC proliferation under such stress. Collectively, our data indicate that microRNA and protein cell fate determinants coordinate to enhance robustness of cell fate decision, and they provide a safeguard mechanism against stem cell proliferation induced by inflammation or oncogenic mutation.
Open Access
Arterial pole progenitors interpret opposing FGF/BMP signals to proliferate or differentiate.
(Development, 2010-09) Hutson, MR; Zeng, XL; Kim, AJ; Antoon, E; Harward, S; Kirby, ML
During heart development, a subpopulation of cells in the heart field maintains cardiac potential over several days of development and forms the myocardium and smooth muscle of the arterial pole. Using clonal and explant culture experiments, we show that these cells are a stem cell population that can differentiate into myocardium, smooth muscle and endothelial cells. The multipotent stem cells proliferate or differentiate into different cardiovascular cell fates through activation or inhibition of FGF and BMP signaling pathways. BMP promoted myocardial differentiation but not proliferation. FGF signaling promoted proliferation and induced smooth muscle differentiation, but inhibited myocardial differentiation. Blocking the Ras/Erk intracellular pathway promoted myocardial differentiation, while the PLCgamma and PI3K pathways regulated proliferation. In vivo, inhibition of both pathways resulted in predictable arterial pole defects. These studies suggest that myocardial differentiation of arterial pole progenitors requires BMP signaling combined with downregulation of the FGF/Ras/Erk pathway. The FGF pathway maintains the pool of proliferating stem cells and later promotes smooth muscle differentiation.
Open Access
Co-evolution of a broadly neutralizing HIV-1 antibody and founder virus.
(Nature, 2013-04-25) Liao, Hua-Xin; Lynch, Rebecca; Zhou, Tongqing; Gao, Feng; Alam, S Munir; Boyd, Scott D; Fire, Andrew Z; Roskin, Krishna M; Schramm, Chaim A; Zhang, Zhenhai; Zhu, Jiang; Shapiro, Lawrence; NISC Comparative Sequencing Program; Mullikin, James C; Gnanakaran, S; Hraber, Peter; Wiehe, Kevin; Kelsoe, Garnett; Yang, Guang; Xia, Shi-Mao; Montefiori, David C; Parks, Robert; Lloyd, Krissey E; Scearce, Richard M; Soderberg, Kelly A; Cohen, Myron; Kamanga, Gift; Louder, Mark K; Tran, Lillian M; Chen, Yue; Cai, Fangping; Chen, Sheri; Moquin, Stephanie; Du, Xiulian; Joyce, M Gordon; Srivatsan, Sanjay; Zhang, Baoshan; Zheng, Anqi; Shaw, George M; Hahn, Beatrice H; Kepler, Thomas B; Korber, Bette TM; Kwong, Peter D; Mascola, John R; Haynes, Barton F
Current human immunodeficiency virus-1 (HIV-1) vaccines elicit strain-specific neutralizing antibodies. However, cross-reactive neutralizing antibodies arise in approximately 20% of HIV-1-infected individuals, and details of their generation could provide a blueprint for effective vaccination. Here we report the isolation, evolution and structure of a broadly neutralizing antibody from an African donor followed from the time of infection. The mature antibody, CH103, neutralized approximately 55% of HIV-1 isolates, and its co-crystal structure with the HIV-1 envelope protein gp120 revealed a new loop-based mechanism of CD4-binding-site recognition. Virus and antibody gene sequencing revealed concomitant virus evolution and antibody maturation. Notably, the unmutated common ancestor of the CH103 lineage avidly bound the transmitted/founder HIV-1 envelope glycoprotein, and evolution of antibody neutralization breadth was preceded by extensive viral diversification in and near the CH103 epitope. These data determine the viral and antibody evolution leading to induction of a lineage of HIV-1 broadly neutralizing antibodies, and provide insights into strategies to elicit similar antibodies by vaccination.
Open Access
Distinct and atypical intrinsic and extrinsic cell death pathways between photoreceptor cell types upon specific ablation of Ranbp2 in cone photoreceptors.
(PLoS Genet, 2013-06) Cho, Kyoung-In; Haque, Mdemdadul; Wang, Jessica; Yu, Minzhong; Hao, Ying; Qiu, Sunny; Pillai, Indulekha CL; Peachey, Neal S; Ferreira, Paulo A
Non-autonomous cell-death is a cardinal feature of the disintegration of neural networks in neurodegenerative diseases, but the molecular bases of this process are poorly understood. The neural retina comprises a mosaic of rod and cone photoreceptors. Cone and rod photoreceptors degenerate upon rod-specific expression of heterogeneous mutations in functionally distinct genes, whereas cone-specific mutations are thought to cause only cone demise. Here we show that conditional ablation in cone photoreceptors of Ran-binding protein-2 (Ranbp2), a cell context-dependent pleiotropic protein linked to neuroprotection, familial necrotic encephalopathies, acute transverse myelitis and tumor-suppression, promotes early electrophysiological deficits, subcellular erosive destruction and non-apoptotic death of cones, whereas rod photoreceptors undergo cone-dependent non-autonomous apoptosis. Cone-specific Ranbp2 ablation causes the temporal activation of a cone-intrinsic molecular cascade highlighted by the early activation of metalloproteinase 11/stromelysin-3 and up-regulation of Crx and CoREST, followed by the down-modulation of cone-specific phototransduction genes, transient up-regulation of regulatory/survival genes and activation of caspase-7 without apoptosis. Conversely, PARP1+ -apoptotic rods develop upon sequential activation of caspase-9 and caspase-3 and loss of membrane permeability. Rod photoreceptor demise ceases upon cone degeneration. These findings reveal novel roles of Ranbp2 in the modulation of intrinsic and extrinsic cell death mechanisms and pathways. They also unveil a novel spatiotemporal paradigm of progression of neurodegeneration upon cell-specific genetic damage whereby a cone to rod non-autonomous death pathway with intrinsically distinct cell-type death manifestations is triggered by cell-specific loss of Ranbp2. Finally, this study casts new light onto cell-death mechanisms that may be shared by human dystrophies with distinct retinal spatial signatures as well as with other etiologically distinct neurodegenerative disorders.
Open Access
Ex vivo expansion of murine and human hematopoietic stem cells.
(Methods Mol Biol, 2014) Doan, Phuong L; Chute, John P
Hematopoietic stem cells have the capacity to self-renew and give rise to the entirety of the mature blood and immune system throughout the lifespan of an organism. Here, we describe methods to isolate and culture murine bone marrow (BM) CD34(-)ckit(+)Sca1(+)Lineage(-) (CD34(-)KSL) hematopoietic stem cells (HSCs). We also describe a method to measure functional HSC content via the competitive repopulation assay. Furthermore, we summarize methods to isolate and culture human CD34(+)CD38(-)Lineage(-) cells which are enriched for human hematopoietic stem and progenitor cells.
Open Access
Human distal lung maps and lineage hierarchies reveal a bipotent progenitor.
(Nature, 2022-04) Kadur Lakshminarasimha Murthy, Preetish; Sontake, Vishwaraj; Tata, Aleksandra; Kobayashi, Yoshihiko; Macadlo, Lauren; Okuda, Kenichi; Conchola, Ansley S; Nakano, Satoko; Gregory, Simon; Miller, Lisa A; Spence, Jason R; Engelhardt, John F; Boucher, Richard C; Rock, Jason R; Randell, Scott H; Tata, Purushothama Rao
Mapping the spatial distribution and molecular identity of constituent cells is essential for understanding tissue dynamics in health and disease. We lack a comprehensive map of human distal airways, including the terminal and respiratory bronchioles (TRBs), which are implicated in respiratory diseases^1-4. Here, using spatial transcriptomics and single-cell profiling of microdissected distal airways, we identify molecularly distinct TRB cell types that have not-to our knowledge-been previously characterized. These include airway-associated LGR5⁺ fibroblasts and TRB-specific alveolar type-0 (AT0) cells and TRB secretory cells (TRB-SCs). Connectome maps and organoid-based co-cultures reveal that LGR5⁺ fibroblasts form a signalling hub in the airway niche. AT0 cells and TRB-SCs are conserved in primates and emerge dynamically during human lung development. Using a non-human primate model of lung injury, together with human organoids and tissue specimens, we show that alveolar type-2 cells in regenerating lungs transiently acquire an AT0 state from which they can differentiate into either alveolar type-1 cells or TRB-SCs. This differentiation programme is distinct from that identified in the mouse lung^5-7. Our study also reveals mechanisms that drive the differentiation of the bipotent AT0 cell state into normal or pathological states. In sum, our findings revise human lung cell maps and lineage trajectories, and implicate an epithelial transitional state in primate lung regeneration and disease.
Open Access
Initial antibodies binding to HIV-1 gp41 in acutely infected subjects are polyreactive and highly mutated.
(J Exp Med, 2011-10-24) Liao, Hua-Xin; Chen, Xi; Munshaw, Supriya; Zhang, Ruijun; Marshall, Dawn J; Vandergrift, Nathan; Whitesides, John F; Lu, Xiaozhi; Yu, Jae-Sung; Hwang, Kwan-Ki; Gao, Feng; Markowitz, Martin; Heath, Sonya L; Bar, Katharine J; Goepfert, Paul A; Montefiori, David C; Shaw, George C; Alam, S Munir; Margolis, David M; Denny, Thomas N; Boyd, Scott D; Marshal, Eleanor; Egholm, Michael; Simen, Birgitte B; Hanczaruk, Bozena; Fire, Andrew Z; Voss, Gerald; Kelsoe, Garnett; Tomaras, Georgia D; Moody, M Anthony; Kepler, Thomas B; Haynes, Barton F
The initial antibody response to HIV-1 is targeted to envelope (Env) gp41, and is nonneutralizing and ineffective in controlling viremia. To understand the origins and characteristics of gp41-binding antibodies produced shortly after HIV-1 transmission, we isolated and studied gp41-reactive plasma cells from subjects acutely infected with HIV-1. The frequencies of somatic mutations were relatively high in these gp41-reactive antibodies. Reverted unmutated ancestors of gp41-reactive antibodies derived from subjects acutely infected with HIV-1 frequently did not react with autologous HIV-1 Env; however, these antibodies were polyreactive and frequently bound to host or bacterial antigens. In one large clonal lineage of gp41-reactive antibodies, reactivity to HIV-1 Env was acquired only after somatic mutations. Polyreactive gp41-binding antibodies were also isolated from uninfected individuals. These data suggest that the majority of gp41-binding antibodies produced after acute HIV-1 infection are cross-reactive responses generated by stimulating memory B cells that have previously been activated by non-HIV-1 antigens.
Open Access
Mammalian genes induce partially reprogrammed pluripotent stem cells in non-mammalian vertebrate and invertebrate species.
(Elife, 2013-09-03) Rosselló, Ricardo Antonio; Chen, Chun-Chun; Dai, Rui; Howard, Jason T; Hochgeschwender, Ute; Jarvis, Erich D
Cells are fundamental units of life, but little is known about evolution of cell states. Induced pluripotent stem cells (iPSCs) are once differentiated cells that have been re-programmed to an embryonic stem cell-like state, providing a powerful platform for biology and medicine. However, they have been limited to a few mammalian species. Here we found that a set of four mammalian transcription factor genes used to generate iPSCs in mouse and humans can induce a partially reprogrammed pluripotent stem cell (PRPSCs) state in vertebrate and invertebrate model organisms, in mammals, birds, fish, and fly, which span 550 million years from a common ancestor. These findings are one of the first to show cross-lineage stem cell-like induction, and to generate pluripotent-like cells for several of these species with in vivo chimeras. We suggest that the stem-cell state may be highly conserved across a wide phylogenetic range. DOI:http://dx.doi.org/10.7554/eLife.00036.001.
Open Access
Multi-site evaluation of the BD Stem Cell Enumeration Kit for CD34(+) cell enumeration on the BD FACSCanto II and BD FACSCalibur flow cytometers.
(Cytotherapy, 2014-11) Preti, Robert A; Chan, Wai Shun; Kurtzberg, Joanne; Dornsife, Ronna E; Wallace, Paul K; Furlage, Rosemary; Lin, Anna; Omana-Zapata, Imelda; Bonig, Halvard; Tonn, Torsten
Background aims
Evaluation of the BD Stem Cell Enumeration Kit was conducted at four clinical sites with flow cytometry CD34(+) enumeration to assess agreement between two investigational methods: (i) the BD FACSCanto II and BD FACSCalibur systems and (ii) the predicate method (Beckman Coulter StemKit and StemTrol, Immunotech SAS, Beckman Coulter, Marseille Cedex 9, France).
Methods
Leftover and delinked specimens (n = 1032) from clinical flow cytometry testing were analyzed on the BD FACSCanto II (n = 918) and BD FACSCalibur (n = 905) in normal and mobilized blood, frozen and thawed bone marrow and leucopheresis and cord blood anticoagulated with citrate phosphate dextrose, anticoagulant citrate dextrose-solution A, heparin and ethylenediaminetetraacetate, alone or in combination. Fresh leucopheresis analysis addressed site equivalency for sample preparation, testing and analysis.
Results
The mean relative bias showed agreement within predefined parameters for the BD FACSCanto II (-2.81 to 4.31 ±7.1) and BD FACSCalibur (-2.69 to 5.2 ±7.9). Results are reported as absolute and relative differences compared with the predicate for viable CD34(+), percentage of CD34(+) in CD45(+) and viable CD45(+) populations (or gates). Bias analyses of the distribution of the predicate low, mid and high bin values were done using BD FACSCanto II optimal gating and BD FACSCalibur manual gating for viable CD34(+), percentage of CD34(+) in CD45(+) and viable CD45(+). Bias results from both investigational methods show agreement. Deming regression analyses showed a linear relationship with R(2) > 0.92 for both investigational methods.
Discussion
In conclusion, the results from both investigational methods demonstrated agreement and equivalence with the predicate method for enumeration of absolute viable CD34(+), percentage of viable CD34(+) in CD45(+) and absolute viable CD45(+) populations.
Open Access
Pairing of competitive and topologically distinct regulatory modules enhances patterned gene expression.
(Mol Syst Biol, 2008) Yanai, Itai; Baugh, L Ryan; Smith, Jessica J; Roehrig, Casey; Shen-Orr, Shai S; Claggett, Julia M; Hill, Andrew A; Slonim, Donna K; Hunter, Craig P
Biological networks are inherently modular, yet little is known about how modules are assembled to enable coordinated and complex functions. We used RNAi and time series, whole-genome microarray analyses to systematically perturb and characterize components of a Caenorhabditis elegans lineage-specific transcriptional regulatory network. These data are supported by selected reporter gene analyses and comprehensive yeast one-hybrid and promoter sequence analyses. Based on these results, we define and characterize two modules composed of muscle- and epidermal-specifying transcription factors that function together within a single cell lineage to robustly specify multiple cell types. The expression of these two modules, although positively regulated by a common factor, is reliably segregated among daughter cells. Our analyses indicate that these modules repress each other, and we propose that this cross-inhibition coupled with their relative time of induction function to enhance the initial asymmetry in their expression patterns, thus leading to the observed invariant gene expression patterns and cell lineage. The coupling of asynchronous and topologically distinct modules may be a general principle of module assembly that functions to potentiate genetic switches.
Open Access
Plasticity of Hopx(+) type I alveolar cells to regenerate type II cells in the lung.
(Nature communications, 2015-04-13) Jain, Rajan; Barkauskas, Christina E; Takeda, Norifumi; Bowie, Emily J; Aghajanian, Haig; Wang, Qiaohong; Padmanabhan, Arun; Manderfield, Lauren J; Gupta, Mudit; Li, Deqiang; Li, Li; Trivedi, Chinmay M; Hogan, Brigid LM; Epstein, Jonathan A
The plasticity of differentiated cells in adult tissues undergoing repair is an area of intense research. Pulmonary alveolar type II cells produce surfactant and function as progenitors in the adult, demonstrating both self-renewal and differentiation into gas exchanging type I cells. In vivo, type I cells are thought to be terminally differentiated and their ability to give rise to alternate lineages has not been reported. Here we show that Hopx becomes restricted to type I cells during development. However, unexpectedly, lineage-labelled Hopx(+) cells both proliferate and generate type II cells during adult alveolar regrowth following partial pneumonectomy. In clonal 3D culture, single Hopx(+) type I cells generate organoids composed of type I and type II cells, a process modulated by TGFβ signalling. These findings demonstrate unanticipated plasticity of type I cells and a bidirectional lineage relationship between distinct differentiated alveolar epithelial cell types in vivo and in single-cell culture.
Open Access
Protective astrogenesis from the SVZ niche after injury is controlled by Notch modulator Thbs4.
(Nature, 2013-05) Benner, Eric J; Luciano, Dominic; Jo, Rebecca; Abdi, Khadar; Paez-Gonzalez, Patricia; Sheng, Huaxin; Warner, David S; Liu, Chunlei; Eroglu, Cagla; Kuo, Chay T
Postnatal/adult neural stem cells (NSCs) within the rodent subventricular zone (SVZ; also called subependymal zone) generate doublecortin (Dcx)(+) neuroblasts that migrate and integrate into olfactory bulb circuitry. Continuous production of neuroblasts is controlled by the SVZ microenvironmental niche. It is generally thought that enhancing the neurogenic activities of endogenous NSCs may provide needed therapeutic options for disease states and after brain injury. However, SVZ NSCs can also differentiate into astrocytes. It remains unclear whether there are conditions that favour astrogenesis over neurogenesis in the SVZ niche, and whether astrocytes produced there have different properties compared with astrocytes produced elsewhere in the brain. Here we show in mice that SVZ-generated astrocytes express high levels of thrombospondin 4 (Thbs4), a secreted homopentameric glycoprotein, in contrast to cortical astrocytes, which express low levels of Thbs4. We found that localized photothrombotic/ischaemic cortical injury initiates a marked increase in Thbs4(hi) astrocyte production from the postnatal SVZ niche. Tamoxifen-inducible nestin-creER(tm)4 lineage tracing demonstrated that it is these SVZ-generated Thbs4(hi) astrocytes, and not Dcx(+) neuroblasts, that home-in on the injured cortex. This robust post-injury astrogenic response required SVZ Notch activation modulated by Thbs4 via direct Notch1 receptor binding and endocytosis to activate downstream signals, including increased Nfia transcription factor expression important for glia production. Consequently, Thbs4 homozygous knockout mice (Thbs4(KO/KO)) showed severe defects in cortical-injury-induced SVZ astrogenesis, instead producing cells expressing Dcx migrating from SVZ to the injury sites. These alterations in cellular responses resulted in abnormal glial scar formation after injury, and significantly increased microvascular haemorrhage into the brain parenchyma of Thbs4(KO/KO) mice. Taken together, these findings have important implications for post-injury applications of endogenous and transplanted NSCs in the therapeutic setting, as well as disease states where Thbs family members have important roles.
Open Access
Rapid and Efficient Generation of Transgene-Free iPSC from a Small Volume of Cryopreserved Blood.
(Stem cell reviews and reports, 2015-08) Zhou, Hongyan; Martinez, Hector; Sun, Bruce; Li, Aiqun; Zimmer, Matthew; Katsanis, Nicholas; Davis, Erica E; Kurtzberg, Joanne; Lipnick, Scott; Noggle, Scott; Rao, Mahendra; Chang, Stephen
Human peripheral blood and umbilical cord blood represent attractive sources of cells for reprogramming to induced pluripotent stem cells (iPSCs). However, to date, most of the blood-derived iPSCs were generated using either integrating methods or starting from T-lymphocytes that have genomic rearrangements thus bearing uncertain consequences when using iPSC-derived lineages for disease modeling and cell therapies. Recently, both peripheral blood and cord blood cells have been reprogrammed into transgene-free iPSC using the Sendai viral vector. Here we demonstrate that peripheral blood can be utilized for medium-throughput iPSC production without the need to maintain cell culture prior to reprogramming induction. Cell reprogramming can also be accomplished with as little as 3000 previously cryopreserved cord blood cells under feeder-free and chemically defined Xeno-free conditions that are compliant with standard Good Manufacturing Practice (GMP) regulations. The first iPSC colonies appear 2-3 weeks faster in comparison to previous reports. Notably, these peripheral blood- and cord blood-derived iPSCs are free of detectable immunoglobulin heavy chain (IGH) and T cell receptor (TCR) gene rearrangements, suggesting they did not originate from B- or T- lymphoid cells. The iPSCs are pluripotent as evaluated by the scorecard assay and in vitro multi lineage functional cell differentiation. Our data show that small volumes of cryopreserved peripheral blood or cord blood cells can be reprogrammed efficiently at a convenient, cost effective and scalable way. In summary, our method expands the reprogramming potential of limited or archived samples either stored at blood banks or obtained from pediatric populations that cannot easily provide large quantities of peripheral blood or a skin biopsy.
Open Access
Rare SOX2+ Airway Progenitor Cells Generate KRT5+ Cells that Repopulate Damaged Alveolar Parenchyma following Influenza Virus Infection.
(Stem cell reports, 2016-11) Ray, Samriddha; Chiba, Norika; Yao, Changfu; Guan, Xiangrong; McConnell, Alicia M; Brockway, Brian; Que, Loretta; McQualter, Jonathan L; Stripp, Barry R
Recent studies have implicated keratin 5 (KRT5)+ cells in repopulation of damaged lung tissue following severe H1N1 influenza virus infection. However, the origins of the cells repopulating the injured alveolar region remain controversial. We sought to determine the cellular dynamics of lung repair following influenza infection and define whether nascent KRT5+ cells repopulating alveolar epithelium were derived from pre-existing alveolar or airway progenitor cells. We found that the wound-healing response begins with proliferation of SOX2+ SCGB1A1- KRT5- progenitor cells in airways. These cells generate nascent KRT5+ cells as an early response to airway injury and yield progeny that colonize damaged alveolar parenchyma. Moreover, we show that local alveolar progenitors do not contribute to nascent KRT5+ cells after injury. Repopulation of injured airway and alveolar regions leads to proximalization of distal airways by pseudostratified epithelium and of alveoli by airway-derived epithelial cells that lack the normal characteristics of mature airway or alveolar epithelium.
Open Access
Regionally distinct progenitor cells in the lower airway give rise to neuroendocrine and multiciliated cells in the developing human lung.
(Proceedings of the National Academy of Sciences of the United States of America, 2023-06) Conchola, Ansley S; Frum, Tristan; Xiao, Zhiwei; Hsu, Peggy P; Kaur, Kamika; Downey, Michael S; Hein, Renee FC; Miller, Alyssa J; Tsai, Yu-Hwai; Wu, Angeline; Holloway, Emily M; Anand, Abhinav; Murthy, Preetish Kadur Lakshminarasimha; Glass, Ian; Tata, Purushothama R; Spence, Jason R
Using scRNA-seq and microscopy, we describe a cell that is enriched in the lower airways of the developing human lung and identified by the unique coexpression of SCGB3A2/SFTPB/CFTR. To functionally interrogate these cells, we apply a single-cell barcode-based lineage tracing method, called CellTagging, to track the fate of SCGB3A2/SFTPB/CFTR cells during airway organoid differentiation in vitro. Lineage tracing reveals that these cells have a distinct differentiation potential from basal cells, giving rise predominantly to pulmonary neuroendocrine cells and a subset of multiciliated cells distinguished by high C6 and low MUC16 expression. Lineage tracing results are supported by studies using organoids and isolated cells from the lower noncartilaginous airway. We conclude that SCGB3A2/SFTPB/CFTR cells are enriched in the lower airways of the developing human lung and contribute to the epithelial diversity and heterogeneity in this region.
Open Access
The Macrophage-Specific Promoter mfap4 Allows Live, Long-Term Analysis of Macrophage Behavior during Mycobacterial Infection in Zebrafish.
(PLoS One, 2015) Walton, Eric M; Cronan, Mark R; Beerman, Rebecca W; Tobin, David M
Transgenic labeling of innate immune cell lineages within the larval zebrafish allows for real-time, in vivo analyses of microbial pathogenesis within a vertebrate host. To date, labeling of zebrafish macrophages has been relatively limited, with the most specific expression coming from the mpeg1 promoter. However, mpeg1 transcription at both endogenous and transgenic loci becomes attenuated in the presence of intracellular pathogens, including Salmonella typhimurium and Mycobacterium marinum. Here, we describe mfap4 as a macrophage-specific promoter capable of producing transgenic lines in which transgene expression within larval macrophages remains stable throughout several days of infection. Additionally, we have developed a novel macrophage-specific Cre transgenic line under the control of mfap4, enabling macrophage-specific expression using existing floxed transgenic lines. These tools enrich the repertoire of transgenic lines and promoters available for studying zebrafish macrophage dynamics during infection and inflammation and add flexibility to the design of future macrophage-specific transgenic lines.
Open Access
Type 2 alveolar cells are stem cells in adult lung.
(The Journal of clinical investigation, 2013-07) Barkauskas, Christina E; Cronce, Michael J; Rackley, Craig R; Bowie, Emily J; Keene, Douglas R; Stripp, Barry R; Randell, Scott H; Noble, Paul W; Hogan, Brigid LM
Gas exchange in the lung occurs within alveoli, air-filled sacs composed of type 2 and type 1 epithelial cells (AEC2s and AEC1s), capillaries, and various resident mesenchymal cells. Here, we use a combination of in vivo clonal lineage analysis, different injury/repair systems, and in vitro culture of purified cell populations to obtain new information about the contribution of AEC2s to alveolar maintenance and repair. Genetic lineage-tracing experiments showed that surfactant protein C-positive (SFTPC-positive) AEC2s self renew and differentiate over about a year, consistent with the population containing long-term alveolar stem cells. Moreover, if many AEC2s were specifically ablated, high-resolution imaging of intact lungs showed that individual survivors undergo rapid clonal expansion and daughter cell dispersal. Individual lineage-labeled AEC2s placed into 3D culture gave rise to self-renewing "alveolospheres," which contained both AEC2s and cells expressing multiple AEC1 markers, including HOPX, a new marker for AEC1s. Growth and differentiation of the alveolospheres occurred most readily when cocultured with primary PDGFRα⁺ lung stromal cells. This population included lipofibroblasts that normally reside close to AEC2s and may therefore contribute to a stem cell niche in the murine lung. Results suggest that a similar dynamic exists between AEC2s and mesenchymal cells in the human lung.
Open Access
Wnt signaling suppresses MAPK-driven proliferation of intestinal stem cells.
(The Journal of clinical investigation, 2018-08) Kabiri, Zahra; Greicius, Gediminas; Zaribafzadeh, Hamed; Hemmerich, Amanda; Counter, Christopher M; Virshup, David M
Intestinal homeostasis depends on a slowly proliferating stem cell compartment in crypt cells, followed by rapid proliferation of committed progenitor cells in the transit amplifying (TA) compartment. The balance between proliferation and differentiation in intestinal stem cells (ISCs) is regulated by Wnt/β-catenin signaling, although the mechanism remains unclear. We previously targeted PORCN, an enzyme essential for all Wnt secretion, and demonstrated that stromal production of Wnts was required for intestinal homeostasis. Here, a PORCN inhibitor was used to acutely suppress Wnt signaling. Unexpectedly, the treatment induced an initial burst of proliferation in the stem cell compartment of the small intestine, due to conversion of ISCs into TA cells with a loss of intrinsic ISC self-renewal. This process involved MAPK pathway activation, as the proliferating cells in the base of the intestinal crypt contained phosphorylated ERK1/2, and a MEK inhibitor attenuated the proliferation of ISCs and their differentiation into TA cells. These findings suggest a role for Wnt signaling in suppressing the MAPK pathway at the crypt base to maintain a pool of ISCs. The interaction between Wnt and MAPK pathways in vivo has potential therapeutic applications in cancer and regenerative medicine.
Open Access
WNT3 is a biomarker capable of predicting the definitive endoderm differentiation potential of hESCs.
(Stem Cell Reports, 2013) Jiang, Wei; Zhang, Donghui; Bursac, Nenad; Zhang, Yi
Generation of functional cells from human pluripotent stem cells (PSCs) through in vitro differentiation is a promising approach for drug screening and cell therapy. However, the observed large and unavoidable variation in the differentiation potential of different human embryonic stem cell (hESC)/induced PSC (iPSC) lines makes the selection of an appropriate cell line for the differentiation of a particular cell lineage difficult. Here, we report identification of WNT3 as a biomarker capable of predicting definitive endoderm (DE) differentiation potential of hESCs. We show that the mRNA level of WNT3 in hESCs correlates with their DE differentiation efficiency. In addition, manipulations of hESCs through WNT3 knockdown or overexpression can respectively inhibit or promote DE differentiation in a WNT3 level-dependent manner. Finally, analysis of several hESC lines based on their WNT3 expression levels allowed accurate prediction of their DE differentiation potential. Collectively, our study supports the notion that WNT3 can serve as a biomarker for predicting DE differentiation potential of hESCs.

Browsing by Subject "Cell Lineage"

Background aims

Methods

Results

Discussion