Cellular Lineage Research Articles

Decoding the mechanisms underlying cell-fate decision-making during stem cell differentiation by random circuit perturbation.

Stem cells can precisely and robustly undergo cellular differentiation and lineage commitment, referred to as stemness. However, how the gene network underlying stemness regulation reliably specifies cell fates is not well understood. To address this question, we applied a recently developed computational method, random circuit perturbation (RACIPE), to a nine-component gene regulatory network (GRN) governing stemness, from which we identified robust gene states. Among them, four out of the five most probable gene states exhibit gene expression patterns observed in single mouse embryonic cells at 32-cell and 64-cell stages. These gene states can be robustly predicted by the stemness GRN but not by randomized versions of the stemness GRN. Strikingly, we found a hierarchical structure of the GRN with the Oct4/Cdx2 motif functioning as the first decision-making module followed by Gata6/Nanog. We propose that stem cell populations, instead of being viewed as all having a specific cellular state, can be regarded as a heterogeneous mixture including cells in various states. Upon perturbations by external signals, stem cells lose the capacity to access certain cellular states, thereby becoming differentiated. The new gene states and key parameters regulating transitions among gene states proposed by RACIPE can be used to guide experimental strategies to better understand differentiation and design reprogramming. The findings demonstrate that the functions of the stemness GRN is mainly determined by its well-evolved network topology rather than by detailed kinetic parameters.

Methylation Patterns and Chromatin Accessibility in Neuroendocrine Lung Cancer.

Lung cancer is the worldwide leading cause of death from cancer. Epigenetic modifications such as methylation and changes in chromatin accessibility are major gene regulatory mechanisms involved in tumorigenesis and cellular lineage commitment. We aimed to characterize these processes in the context of neuroendocrine (NE) lung cancer. Illumina 450K DNA methylation data were collected for 1407 lung cancers including 27 NE tumors. NE differentially methylated regions (NE-DMRs) were identified and correlated with gene expression data for 151 lung cancers and 31 human tissue entities from the Genotype-Tissue Expression (GTEx) consortium. Assay for transposase-accessible chromatin sequencing (ATAC-seq) and RNA sequencing (RNA-seq) were performed on eight lung cancer cell lines, including three NE cell lines, to identify neuroendocrine specific gene regulatory elements. We identified DMRs with methylation patterns associated with differential gene expression and an NE tumor phenotype. DMR-associated genes could further be split into six functional modules, including one highly specific gene module for NE lung cancer showing high expression in both normal and malignant brain tissue. The regulatory potential of NE-DMRs was further validated in vitro using paired ATAC- and RNA-seq and revealed both proximal and distal regulatory elements of canonical NE-marker genes such as CHGA, NCAM1, INSM1, as well as a number of novel candidate markers of NE lung cancer. Using multilevel genomic analyses of both tumor bulk tissue and lung cancer cell lines, we identified a large catalogue of gene regulatory elements related to the NE phenotype of lung cancer.

Quantitative characterization of proliferative cells subpopulations in the hilus of the hippocampus of adult Wistar rats: an integrative study.

The hilus plays an important role modulating the excitability of the hippocampal dentate gyrus (DG). It also harbors proliferative cells whose proliferation rate is modified during pathological events. However, the characterization of these cells, in terms of cellular identity, lineage, and fate, as well as the morphology and proportion of each cell subpopulation has been poorly studied. Therefore, a deeper investigation of hilar proliferative cells might expand the knowledge not only in the physiology, but in the pathophysiological processes related to the hippocampus too. The aim of this work was to perform an integrative study characterizing the identity of proliferative cells populations harbored in the hilus, along with morphology and proportion. In addition, this study provides comparative evidence of the subgranular zone (SGZ) of the DG. Quantified cells included proliferative, neural precursor, Type 1, oligodendrocyte progenitor (OPCs), neural progenitor (NPCs), and proliferative mature astrocytes in the hilus and SGZ of Wistar adult rats. Our results showed that 84% of the hilar proliferative cells correspond to neural precursor cells, OPCs and NPCs being the most abundant at 54 and 45%, respectively, unlike the SGZ, where OPCs represent only 11%. Proliferative mature astrocytes and Type 1-like cells were rarely observed in the hilus. Together, our results lay the basis for future studies focused on the lineage and fate of hilar proliferative cells and suggest that the hilus could be relevant to the formation of new cells that modulate multiple physiological processes governed by the hippocampus.

Cell-cell contacts specify cell fate

Developmental Biology Ascidians, or sea squirts, are marine invertebrate filter feeders with highly reproducible cellular events and invariant embryonic cell lineages. Guignard et al. studied the ascidian embryo to address the determinants of this cellular reproducibility. They introduce computational methods for the robust and automated segmentation, tracking, and analysis of whole-cell behaviors in high-throughput light-sheet microscopy datasets. This work shows that cell induction can be controlled by the contact area among cells. The range of cell signaling is proposed to set the scale at which animal embryonic reproducibility is observed. A high level of reproducibility of embryonic geometries may also counter-intuitively lift constraints on genome evolution, thereby contributing to the rapid molecular evolution observed in ascidians. Science , this issue p. [eaar5663][1] [1]: /lookup/doi/10.1126/science.aar5663

From clocks to dominoes: lessons on cell cycle remodelling from embryonic stem cells.

Cell division is a fundamental cellular process and the evolutionarily conserved networks that control cell division cycles adapt during development, tissue regeneration, cell de-differentiation and reprogramming, and a variety of pathological conditions. Embryonic development is a prime example of such versatility: fast, clock-like divisions hallmarking embryonic cells at early developmental stages become slower and controlled during cellular differentiation and lineage specification. In this review, we compare and contrast the unique cell cycle of mouse and human embryonic stem cells with that of early embryonic cells and of differentiated cells. We propose that embryonic stem cells provide an extraordinarily useful model system to understand cell cycle remodelling during embryonic-to-somatic transitions. We discuss how cell cycle networks help sustain embryonic stem cell pluripotency and self-renewal and how they safeguard cell identity and proper cell number in differentiated cells. Finally, we highlight the incredible diversity in cell cycle regulation within mammals and discuss the implications of studying cell cycle remodelling for understanding healthy and disease states.

Transovarial Transmission of Bacteriome-Associated Symbionts in the Cicada Pycna repanda (Hemiptera: Cicadidae).

Although transovarial transmission of bacteriome-associated symbionts in hemipteran insects is extremely important for maintaining intimate host-symbiont associations, our knowledge of cellular mechanisms underlying the transmission process is quite limited. We investigated bacterial communities of salivary glands, bacteriomes, and digestive and reproductive organs and clarified the transovarial transmission of bacteriome-associated symbionts of the mountain-habitat specialist Pycna repanda using integrated methods. The bacterial communities among different gut tissues and those of bacteriomes of males and females both show similarity, whereas differences are exhibited among bacterial communities in testes and ovaries. The primary symbionts "Candidatus Sulcia muelleri" (hereafter "Ca Sulcia") and "Candidatus Hodgkinia cicadicola" (hereafter "Ca Hodgkinia") were not only restricted to but also dominant in the bacteriomes and ovaries. "Ca Hodgkinia" cells in the bacteriomes of both sexes exhibited different colors by histological and electron microscopy. Also considering the results of a restriction fragment length polymorphism (RFLP)-based cloning approach, we hypothesize that "Ca Hodgkinia" may have split into cytologically different cellular lineages within this cicada species. Regarding the dominant secondary symbionts, Rickettsia was detected in the salivary glands, digestive organs, and testes, whereas Arsenophonus was detected in the bacteriomes and ovaries. Our results show that Arsenophonus can coexist with "Ca Sulcia" and "Ca Hodgkinia" within bacteriomes and can be transovarially transmitted with these obligate symbionts together from mother to offspring in cicadas, but it is not harbored in the cytoplasm of "Ca Sulcia." The change in the shape of "Ca Sulcia" and "Ca Hodgkinia" during the transovarial transmission process is hypothesized to be related to the limited space and novel microenvironment.IMPORTANCE Cicadas establish an intimate symbiosis with microorganisms to obtain essential nutrients that are extremely deficient in host plant sap. Previous studies on bacterial communities of cicadas mainly focused on a few widely distributed species, but knowledge about mountain-habitat species is quite poor. We initially revealed the physical distribution of the primary symbionts "Ca Sulcia" and "Ca Hodgkinia" and the dominant secondary symbionts Rickettsia and Arsenophonus in the mountain-habitat specialist Pycna repanda and then clarified the transovarial transmission process of bacteriome-associated symbionts in this species. Our observations suggest that "Ca Hodgkinia" may have split into cytologically distinct lineages within this cicada species, and related cicadas might have developed complex mechanisms for the vertical transmission of the bacteriome-associated symbionts. We also revealed that Arsenophonus can be transovarially transmitted in auchenorrhynchan insects when it is not harbored in the cytoplasm of other endosymbionts. Our results highlight transovarial transmission mechanisms of bacteriome-associated symbionts in sap-feeding insects.

Assembly and Function of a Bioengineered Human Liver for Transplantation Generated Solely from Induced Pluripotent Stem Cells

The availability of an autologous transplantable auxiliary liver would dramatically affect the treatment of liver disease. Assembly and function invivo of a bioengineered human liver derived from induced pluripotent stem cells (iPSCs) has not been previously described. By improving methods for liver decellularization, recellularization, and differentiation of different liver cellular lineages of human iPSCs in an organ-like environment, we generated functional engineered human mini livers and performed transplantation in a rat model. Whereas previous studies recellularized liver scaffolds largely with rodent hepatocytes, we repopulated not only the parenchyma with human iPSC-hepatocytes but also the vascular system with human iPS-endothelial cells, and the bile duct network with human iPSC-biliary epithelial cells. The regenerated human iPSC-derived mini liver containing multiple cell types was tested invivo and remained functional for 4days after auxiliary liver transplantation in immunocompromised, engineered (IL2rg-/-) rats.

Sudden severe thrombocytopenia in a patient in the recovery stage of COVID-19

On Jan 23, 2020 (day 1 of infection), a 38-year-old man developed a cough and dyspnoea, followed by fever and muscle aches. On day 13, he attended the outpatient department of the Union Hospital, Wuhan. A chest CT scan showed multiple ground-glass densities (appendix p 1), a blood test showed normal platelet count (196 × 109 cells per L), and the COVID-19 nucleic acid test was positive. He was diagnosed with moderate COVID-19 and admitted to hospital on day 20. All other laboratory tests were within the normal reference range (except for increased concentration of fibrinogen at admission [5·37 g/L, reference range 2·0–4·0], appendix p 2). After admission, he was given antiviral treatment of interferon-α (5 million units twice daily for 9 days, aerosol inhalation) and umifenovir (0·2 g three times daily for 7 days, orally) according to the COVID-19 diagnosis and treatment plan (trial sixth edition) issued by the National Health Commission of China. The patient's symptoms improved, and the pulmonary lesions appeared to have been absorbed after one week (appendix p 1). When the COVID-19 nucleic acid test showed negative twice (day 27 and day 28), he met the discharge criteria. However, on day 29 a blood test showed a decreased platelet count of 2 × 109 cells per L, and fibrinogen concentration remained elevated (4·40 g/L), while other markers were within the normal range (appendix p 2). These results showed a clear, isolated thrombocytopenia. Lymphocyte subset and autoimmune antibody analysis at platelet nadir time showed an increase of the percentage of B cells, from 18·62% on day 21 to 34·80% on day 29 (reference range 4·10–18·31%, appendix p 2) and autoimmune antibodies were negative. Bone marrow aspiration was done (for biosecurity reasons, bone marrow smears were fumigated with formaldehyde for 6 h before Wright's staining); most cellular lineages were normal except for low numbers of platelet-producing megakaryocytes (figure, appendix p 3). A COVID-19 nucleic acid test of the bone marrow aspirate was negative. There were no signs of bleeding or thrombosis during hospital admission or during the time of platelet nadir, and he had never been admitted to the intensive care unit. Our differential diagnosis included complications of acute COVID-19 infection and post-infectious immune thrombocytopenia. We administered intravenous immunoglobulin (400 mg/kg daily) and dexamethasone (10 mg daily). The patient's platelet count increased to 60 × 109 cells per L 3 days later (day 33) and dexamethasone was stopped in case of re-activation of viral replication. The platelet count was normal on day 37, so immunoglobulin was ceased. After the time of platelet nadir (day 29), we monitored the patient for 2 weeks; his platelet count remained in the normal range and B-cell percentage gradually decreased (16·47% on day 45, appendix p 2). The patient recovered and was discharged on day 46, 4 days after the last chest CT scan (day 42, appendix p 1). Thrombocytopenia has been shown to occur in patients with COVID-19, usually noted on admission to hospital, although here thrombocytopenia occurred later in the disease course. The effectiveness of immunoregulatory treatment, the changing concentrations of B lymphocytes, and the results of the bone marrow aspirate, suggest immune-mediated thrombocytopenia in this patient, and the normal prothombin time and activated partial thromboplastin time suggest that other coagulation abnormalities were not the cause of the severe thrombocytopenia. Post-viral immune thrombocytopenia arising after infection with a range of pathogens, including severe acute respiratory syndrome coronavirus (SARS-CoV), influenza, and Zika virus, has been described in previous case reports (appendix p 4). However, the findings that we present here should be interpreted cautiously. Furthermore, we could not rule out the possibility of drug-induced thrombocytopenia, or increased platelet destruction with or without decreased platelet genesis in the damaged lung tissue, as the lungs also contribute to platelet biogenesis. Contributors WC, BY, and ZL drafted and revised the submitted article and contributed equally. BY was the health-care provider of the patient. PW and YC provided constructive criticisms and suggestions. HZ was involved in preparation of the manuscript and revision of the submitted article. This study was approved by the Ethics Committee of the Union hospital, Tongji Medical College, Huazhong University of Science and Technology (No. 2020-0079-1). Written informed consent to publication was obtained. Declaration of interests We declare no competing interests. Download .pdf (.8 MB) Help with pdf files Supplementary appendix

Atlas of gastrulation

Developmental Biology We marvel at the progression of a single cell into a complex organism, and microscopy has long been used to visualize early developmental events. More recently, molecular networks and cellular lineages have been constructed by measuring cells' gene expression profile through single-cell RNA sequencing (scRNA-seq). Sladitschek et al. combined scRNA-seq and light-sheet imaging of the ascidian Phallusia mammillata to reveal gene expression in all cells of the embryo up to the formation of the multilayered gastrula. Every cell was followed for all cell divisions in 18 cell lineages. The result is a map of cell spatial position and lineage history that reveals embryonic bilateral symmetry and interembryonic variability, as well as the patterned expression of cell adhesion molecules. This resource can be used to examine any number of molecular mechanisms and developmental events occurring in the gastrulating embryo and can serve as model for the spatiotemporal map. Cell 10.1016/j.cell.2020.03.055 (2020).

Inhibition of TET (Ten-Eleven Translocation) enzymes enhances systemic anti-tumor immune responses in T cells

Abstract TET enzymes facilitate DNA demethylation by oxidizing 5-methylcytosine to 5-hydroxymethylcytosine and other oxidation products in DNA. Loss-of-function mutations in TET enzymes are associated with increased proliferation and increased stem cell function in many cellular lineages. Moreover, there are several hints that inhibition of TET enzymes in tumor-infiltrating T cells might enhance anti tumor immune responses in solid tumors. For instance, TET2 deficiency in mouse T cells increased the number of CD8+ central memory T cells, and TET deficiency human CD8 chimeric antigen receptor (CAR) T cells increased their antigen-specific proliferation and capacity to reject tumor cells in a patient with chronic lymphocytic leukemia. Furthermore, we previously showed that TET deficiency in regulatory T cells decreased the stability of Foxp3 expression; hence TET deficiency would be expected to counter the ability of regulatory T cells to suppress anti-tumor responses. In this study, we found that TET loss of function in CD8 TILs indeed slowed tumor growth and promoted anti tumor responses in a mouse CAR T cell model. The function of TET proteins and other Fe(II) and a-ketoglutarate dependent dioxygenases is inhibited by L-2-Hydroxyglutarate (L2HG), which is normally kept at low levels by the enzyme L-2HG dehydrogenase (L2HGDH). We found that when CAR T cells were rendered low in TET activity in any one of three ways: (i) deficiency of the TET enzymes, (ii) depletion of L2HGDH and (iii) pretreatment of L2HG, they showed decreased expression of inhibitory receptors as well as increased secretion of inflammatory cytokines. Based on these results, we suggest that TET inhibition in T cells might be a promising general approach in cancer immunotherapy.

Landscape of bone marrow T cells in acquired aplastic anaemia revealed by single-cell sequencing

Abstract Objective Acquired aplastic anaemia (AA) is a T-cell-mediated autoimmune disease characterized by hematopoietic stem cell destruction in the bone marrow (BM). The aim of our study is to explore the cellular heterogeneity, lineage and functional states of T cells involved in the pathogenesis of AA. Methods CD3+CD4+ and CD3+CD8+ mature T cells, isolated from BM of five newly diagnosed severe AA patients and two healthy controls by FACS, were subjected to single-cell RNA sequencing (ScRNA-seq) and T cell receptor (TCR) sequences using 10X Genomics Chromium Single Cell 5′ and Single-Cell V(D)J protocols. Libraries were sequenced on Illumina NovaSeq platforms. Results We obtained transcriptome data for 47,508 cells from severe AA patients and 20,758 cells from controls. Bioinformatic analysis of the transcriptional profiles and TCR sequences revealed their molecular and functional properties and developmental trajectory. All clusters are not library specific, but consisted of cells from 7 different donors. We identified all major cell types and signature genes for each subset. We discovered a marked decrease of three heat shock protein family A (Hsp70) members (HSPA6, HSPA1A and HSPA1B) as a signature of AA patients. Interestingly, this phenomenon occurred for all T cell subpopulations. GO annotations related to these genes included response to temperature stimulus, unfolded protein binding and protein folding. We suspected these Hsp70 members were closely related to the pathogenesis of AA. Conclusions Our results establish a reference map of human BM T cells in health and AA patients. and demonstrate that T cells have unique characteristics in AA patients, which may represent a pathogenesis of this autoimmune disease.

Mural Cell SDF1 Signaling Is Associated with the Pathogenesis of Pulmonary Arterial Hypertension.

Pulmonary artery smooth muscle cells (PASMCs) and pericytes are NG2+ mural cells that provide structural support to pulmonary arteries and capillaries. In pulmonary arterial hypertension (PAH), both mural cell types contribute to PA muscularization, but whether similar mechanisms are responsible for their behavior is unknown. RNA-seq was used to compare the gene profile of pericytes and PASMCs from PAH and healthy lungs. NG2-Cre-ER mice were used to generate NG2-selective reporter mice (NG2tdT) for cell lineage identification and tamoxifen-inducible mice for NG2-selective SDF1 knockout (SDF1NG2-KO). Hierarchical clustering of RNA-seq data demonstrated that the genetic profile of PAH pericytes and PASMCs is highly similar. Cellular lineage staining studies on NG2tdT mice in chronic hypoxia showed that, similar to PAH, tdT+ cells accumulate in muscularized microvessels and demonstrate significant upregulation of SDF1, a chemokine involved in chemotaxis and angiogenesis. Compared with control mice, SDF1NG2-KO mice in chronic hypoxia had reduced muscularization and lower abundance of NG2+ cells around microvessels. SDF1 stimulation in healthy pericytes induced greater contractility and impaired their capacity to establish endothelial-pericyte communications. In contrast, SDF1 knockdown reduced PAH pericyte contractility and improved their capacity to associate with vascular tubes in coculture. SDF1 is upregulated in NG2+ mural cells and is associated with PA muscularization. Targeting SDF1 could help prevent and/or reverse muscularization in PAH.

Endogenous CRISPR/Cas9 arrays for scalable whole-organism lineage tracing.

The past decade has seen a renewed appreciation of the central importance of cellular lineages to many questions in biology (especially organogenesis, stem cells and tumor biology). This has been driven in part by a renaissance in genetic clonal-labeling techniques. Recent approaches are based on accelerated mutation of DNA sequences, which can then be sequenced from individual cells to re-create a 'phylogenetic' tree of cell lineage. However, current approaches depend on making transgenic alterations to the genome in question, which limit their application. Here, we introduce a new method that completely avoids the need for prior genetic engineering, by identifying endogenous CRISPR/Cas9 target arrays suitable for lineage analysis. In both mouse and zebrafish, we identify the highest quality compact arrays as judged by equal base composition, 5' G sequence, minimal likelihood of residing in the functional genome, minimal off targets and ease of amplification. We validate multiple high-quality endogenous CRISPR/Cas9 arrays, demonstrating their utility for lineage tracing. Our pragmatically scalable technique thus can produce deep and broad lineages in vivo, while removing the dependence on genetic engineering.

The YAP/TAZ Pathway in Osteogenesis and Bone Sarcoma Pathogenesis.

YAP and TAZ are intracellular messengers communicating multiple interacting extracellular biophysical and biochemical cues to the transcription apparatus in the nucleus and back to the cell/tissue microenvironment interface through the regulation of cytoskeletal and extracellular matrix components. Their activity is negatively and positively controlled by multiple phosphorylation events. Phenotypically, they serve an important role in cellular plasticity and lineage determination during development. As they regulate self-renewal, proliferation, migration, invasion and differentiation of stem cells, perturbed expression of YAP/TAZ signaling components play important roles in tumorigenesis and metastasis. Despite their high structural similarity, YAP and TAZ are functionally not identical and may play distinct cell type and differentiation stage-specific roles mediated by a diversity of downstream effectors and upstream regulatory molecules. However, YAP and TAZ are frequently looked at as functionally redundant and are not sufficiently discriminated in the scientific literature. As the extracellular matrix composition and mechanosignaling are of particular relevance in bone formation during embryogenesis, post-natal bone elongation and bone regeneration, YAP/TAZ are believed to have critical functions in these processes. Depending on the differentiation stage of mesenchymal stem cells during endochondral bone development, YAP and TAZ serve distinct roles, which are also reflected in bone tumors arising from the mesenchymal lineage at different developmental stages. Efforts to clinically translate the wealth of available knowledge of the pathway for cancer diagnostic and therapeutic purposes focus mainly on YAP and TAZ expression and their role as transcriptional co-activators of TEAD transcription factors but rarely consider the expression and activity of pathway modulatory components and other transcriptional partners of YAP and TAZ. As there is a growing body of evidence for YAP and TAZ as potential therapeutic targets in several cancers, we here interrogate the applicability of this concept to bone tumors. To this end, this review aims to summarize our current knowledge of YAP and TAZ in cell plasticity, normal bone development and bone cancer.

Memory of Divisional History Directs the Continuous Process of Primitive Hematopoietic Lineage Commitment.

SummaryHematopoietic stem cells (HSCs) exist in a dormant state and progressively lose regenerative potency as they undergo successive divisions. Why this functional decline occurs and how this information is encoded is unclear. To better understand how this information is stored, we performed RNA sequencing on HSC populations differing only in their divisional history. Comparative analysis revealed that genes upregulated with divisions are enriched for lineage genes and regulated by cell-cycle-associated transcription factors, suggesting that proliferation itself drives lineage priming. Downregulated genes are, however, associated with an HSC signature and targeted by the Polycomb Repressive Complex 2 (PRC2). The PRC2 catalytic subunits Ezh1 and Ezh2 promote and suppress the HSC state, respectively, and successive divisions cause a switch from Ezh1 to Ezh2 dominance. We propose that cell divisions drive lineage priming and Ezh2 accumulation, which represses HSC signature genes to consolidate information on divisional history into memory.

PD52-05 ASSESSING PAM50 MOLECULAR SUBTYPES BY RACE AND OUTCOMES IN MEN WITH LOCALIZED PROSTATE CANCER

You have accessJournal of UrologyProstate Cancer: Markers II (PD52)1 Apr 2020PD52-05 ASSESSING PAM50 MOLECULAR SUBTYPES BY RACE AND OUTCOMES IN MEN WITH LOCALIZED PROSTATE CANCER Yaw Nyame*, Xiaoyu Wang, Kristina Jordahl, James Dai, Dean Troyer, Raymond Lance, Jonathan Wright, and Janet Stanford Yaw Nyame*Yaw Nyame* More articles by this author , Xiaoyu WangXiaoyu Wang More articles by this author , Kristina JordahlKristina Jordahl More articles by this author , James DaiJames Dai More articles by this author , Dean TroyerDean Troyer More articles by this author , Raymond LanceRaymond Lance More articles by this author , Jonathan WrightJonathan Wright More articles by this author , and Janet StanfordJanet Stanford More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000954.05AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Molecular subtyping using the PAM50 classifier has demonstrated associations with disease prognosis and treatment response in breast and prostate cancer. This study aims to evaluate whether there are differences between African American (AA) and white men in the predominant cellular lineage of prostate tumors. METHODS: This is an analysis of a pooled cohort comprised of AA or white men with localized prostate cancer treated with radical prostatectomy from the Fred Hutchinson Cancer Research Center (n=501), Eastern Virginia Medical School (n=124), and The Cancer Genome Atlas (n=472). Using previously described PAM50 methodology, a nearest centroid classifier was applied on each dataset and classified tumors into the following three categories based on gene expression data: (1) luminal A, (2) luminal B, and (3) basal. Kaplan-Meier analysis stratified by race was conducted to estimate progression-free survival—defined as freedom from biochemical failure, metastases, or prostate cancer mortality—and prostate cancer specific survival. Statistical significance was calculated using the log-rank test. RESULTS: In total, 1,097 unique patients were evaluated. AA men represented 13% (n=143) of the dataset. Luminal A was the most common subtype among AA men (50.4%) compared to white men (38.4%, p < 0.001). Basal subtype (16.8% vs. 22.9%, p = 0.13) and luminal B (32.9% vs. 38.8%, p = 0.21) were less common among AA men compared to white men, respectively. On univariable analysis, luminal B was associated with lower rates of progression-free survival and prostate cancer specific survival when compared to luminal A and basal tumors (Figure 1, both p < 0.01). These observations remained consistent when stratified by race. The 10-year cumulative freedom from disease progression was 52%, 78.9%, and 73.1% among AA men and 62.2%, 73.1%, and 71.3% among white men, for luminal B, luminal A, and basal subtypes respectively. CONCLUSIONS: AA men demonstrated a higher proportion of luminal A tumors; however, AA men with luminal B tumors had the worse clinical outcomes in a pooled dataset of prostatectomy patients. Larger cohorts enriched for AA men are needed to confirm these results and better understand cellular lineage of prostate cancer by race and its impact on treatment response and cancer-specific survival. Source of Funding: none © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e1091-e1091 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Yaw Nyame* More articles by this author Xiaoyu Wang More articles by this author Kristina Jordahl More articles by this author James Dai More articles by this author Dean Troyer More articles by this author Raymond Lance More articles by this author Jonathan Wright More articles by this author Janet Stanford More articles by this author Expand All Advertisement PDF downloadLoading ...

A Synthesis Concerning Conservation and Divergence of Cell Types across Epithelia.

Advances in single-cell RNA-seq (scRNA-seq) and computational analysis have enabled the systematic interrogation of the cellular composition of tissues. Combined with tools from developmental biology, cell biology, and genetics, these approaches are revealing fundamental aspects of tissue geometry and physiology, including the distribution, origins, and inferred functions of specialized cell types, and the dynamics of cellular turnover and differentiation. By comparing different tissues, such studies can delineate shared and specialized features of cell types and their lineage. Here, we compare two developmentally related murine epithelia, the airway and the small intestinal epithelia, which are both derived from the embryonic endodermal gut tube. We examine how airway and intestine generate and functionalize common archetypal cell types to fulfill similar shared physiologic functionalities. We point to cases in which similar cell types are repurposed to accommodate each tissue's unique physiologic role, and highlight tissue-specific cells whose specializations contribute to the distinct functional roles of each organ. We discuss how archetypal and unique cell types are incorporated within a cellular lineage, and how the regulation of the proportions of these cell types enables tissue-level organization to meet functional demands and maintain homeostasis.

Bone marrow adipose cells - cellular interactions and changes with obesity.

The bone marrow is a spatially restricted niche, housing cells of the hematopoietic and mesenchymal lineages in various hierarchical commitment states. Although highly localized, cells within this niche are also subject to regulation by environmental and/or circulatory changes through extensive vascularization. Bone marrow adipocytes, derived from mesenchymal stem cells and once known as marrow space fillers, are a heterogeneous population. These cells reside in distinct niches within the bone marrow and interact with proximal cells, such as hematopoietic precursors and lineage-committed cells. In this diverse cellular milieu, bone marrow adipocytes influence commitment decisions and cellular lineage selection by interacting with stem and progenitor cells. In addition, bone marrow adipocytes respond to environmental changes, such as obesity, by undergoing hypertrophy, hyperplasia or adoption of characteristics resembling those of peripheral brown, beige or white adipocytes. Here, we review recent findings and concepts on the influence of bone marrow adipocytes on hematopoietic and other cellular lineages within this niche. We discuss how changes in local, systemic, cellular and secreted signals impact on mesenchymal stem cell expansion, differentiation and lineage commitment. Furthermore, we highlight that bone marrow adipocytes may be intermediaries conveying environmental cues to influence hematopoietic cellular survival, proliferation and preferential differentiation.

Platelets Disseminate Extracellular Vesicles in Lymph in Rheumatoid Arthritis.

The lymphatic system is a circulatory system that unidirectionally drains the interstitial tissue fluid back to blood circulation. Although lymph is utilized by leukocytes for immune surveillance, it remains inaccessible to platelets and erythrocytes. Activated cells release submicron extracellular vesicles (EV) that transport molecules from the donor cell. In rheumatoid arthritis, EV accumulate in the joint where they can interact with numerous cellular lineages. However, whether EV can exit the inflamed tissue to recirculate is unknown. Here, we investigated whether vascular leakage that occurs during inflammation could favor EV access to the lymphatic system. Approach and Results: Using an in vivo model of autoimmune inflammatory arthritis, we show that there is an influx of platelet EV, but not EV from erythrocytes or leukocytes, in joint-draining lymph. In contrast to blood platelet EV, lymph platelet EV lacked mitochondrial organelles and failed to promote coagulation. Platelet EV influx in lymph was consistent with joint vascular leakage and implicated the fibrinogen receptor α2bβ3 and platelet-derived serotonin. These findings show that platelets can disseminate their EV in fluid that is inaccessible to platelets and beyond the joint in this disease.

Abstract ES10-1: Cellular Plasticity, Fate, Potential and Lineage Commitment of Mammary Gland Stem Cells

Abstract Stem cells ensure tissue development, homeostasis and repair. We have recently developed new methods to study by lineage tracing the cellular hierarchy and clonal dynamics that govern the development and homeostasis of the mammary gland. I will present new studies combining lineage tracing, clonal analysis, lineage ablation, single cell RNA sequencing, chromatin profiling, and functional experiments in vivo to investigate the cellular and molecular mechanisms regulating multipotency and lineage restriction during mammary gland development and the cellular reprograming occurring after oncogene expression. Defining the mechanisms regulating tissue expansion and cell fate during development and adult regeneration and understanding how these mechanisms are corrupted during tumorigenesis will have important implications for regenerative medicine and cancer therapy. This work is supported by the ERC, WELBIO, FNRS, TELEVIE, and the Fondation Baillet-Latour. Citation Format: C Blanpain. Cellular Plasticity, Fate, Potential and Lineage Commitment of Mammary Gland Stem Cells [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr ES10-1.