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Cell Nov 2018The mammalian liver possesses a remarkable regenerative ability. Two modes of damage response have been described: (1) The "oval cell" response emanates from the biliary...
The mammalian liver possesses a remarkable regenerative ability. Two modes of damage response have been described: (1) The "oval cell" response emanates from the biliary tree when all hepatocytes are affected by chronic liver disease. (2) A massive, proliferative response of mature hepatocytes occurs upon acute liver damage such as partial hepatectomy (PHx). While the oval cell response has been captured in vitro by growing organoids from cholangiocytes, the hepatocyte proliferative response has not been recapitulated in culture. Here, we describe the establishment of a long-term 3D organoid culture system for mouse and human primary hepatocytes. Organoids can be established from single hepatocytes and grown for multiple months, while retaining key morphological, functional and gene expression features. Transcriptional profiles of the organoids resemble those of proliferating hepatocytes after PHx. Human hepatocyte organoids proliferate extensively after engraftment into mice and thus recapitulate the proliferative damage-response of hepatocytes.
Topics: Animals; Cell Culture Techniques; Cell Proliferation; Cells, Cultured; Hepatocytes; Humans; Mice; Mice, Inbred BALB C; Mice, Knockout; Organoids; Stem Cells; Time Factors
PubMed: 30500538
DOI: 10.1016/j.cell.2018.11.013 -
Hepatology (Baltimore, Md.) Mar 2021Hepatocytes undergo profound metabolic rewiring when primed to proliferate during compensatory regeneration and in hepatocellular carcinoma (HCC). However, the metabolic...
BACKGROUND AND AIMS
Hepatocytes undergo profound metabolic rewiring when primed to proliferate during compensatory regeneration and in hepatocellular carcinoma (HCC). However, the metabolic control of these processes is not fully understood. In order to capture the metabolic signature of proliferating hepatocytes, we applied state-of-the-art systems biology approaches to models of liver regeneration, pharmacologically and genetically activated cell proliferation, and HCC.
APPROACH AND RESULTS
Integrating metabolomics, lipidomics, and transcriptomics, we link changes in the lipidome of proliferating hepatocytes to altered metabolic pathways including lipogenesis, fatty acid desaturation, and generation of phosphatidylcholine (PC). We confirm this altered lipid signature in human HCC and show a positive correlation of monounsaturated PC with hallmarks of cell proliferation and hepatic carcinogenesis.
CONCLUSIONS
Overall, we demonstrate that specific lipid metabolic pathways are coherently altered when hepatocytes switch to proliferation. These represent a source of targets for the development of therapeutic strategies and prognostic biomarkers of HCC.
Topics: Animals; Carcinoma, Hepatocellular; Cell Proliferation; Gene Expression Profiling; Hepatocytes; Humans; Lipid Metabolism; Lipidomics; Lipogenesis; Liver Neoplasms; Male; Metabolic Networks and Pathways; Metabolomics; Mice; Mice, Inbred C57BL
PubMed: 32460431
DOI: 10.1002/hep.31391 -
Der Pathologe Feb 2021Organizing pneumonia (OP) describes a histological pattern of acute or subacute lung damage. Clinically, patients present with cough, fever, and dyspnea. A distinction... (Review)
Review
Organizing pneumonia (OP) describes a histological pattern of acute or subacute lung damage. Clinically, patients present with cough, fever, and dyspnea. A distinction is made between idiopathic or cryptogenic organizing pneumonia (COP) and secondary organizing pneumonia (OP). In COP, neither clinical/radiological nor histological causes can be determined. It is classified as an interstitial idiopathic pneumonia (IIP) according to the criteria of the American Thoracic Society (ATS) and the European Respiratory Society (ERS). Secondary organizing pneumonia has a known triggering mechanism, such as infectious agents, certain medications, or concomitant symptoms of other primary pulmonary diseases and diseases of other organ systems. Common to both forms is the histological picture of intra-alveolar mesenchymal buds. These are myofibroblast proliferates that branch out along the alveolar spaces. They are usually accompanied by a moderate interstitial and alveolar, chronic, and macrophage-rich inflammatory cell infiltrate. The most important differential diagnosis is common interstitial pneumonia (UIP). It also shows fibroblast proliferates, which are, however, located in the interstitium. The correct classification of an IIP as a COP by means of clinical, radiological, and histological findings is essential, since the COP, in contrast to the UIP, responds very well to corticosteroids and therefore has an excellent prognosis compared to the UIP. The course of secondary organizing pneumonia depends on the respective underlying disease. Here it is important for the pathologist to correctly identify potential accompanying histological characteristics in order to be able to provide clues to a possible cause of OP.
Topics: Cryptogenic Organizing Pneumonia; Humans; Lung; Lung Diseases, Interstitial; Pneumonia; Prognosis
PubMed: 33462627
DOI: 10.1007/s00292-020-00903-8 -
ELife Mar 2016Antigen Ki-67 is a nuclear protein expressed in proliferating mammalian cells. It is widely used in cancer histopathology but its functions remain unclear. Here, we show...
Antigen Ki-67 is a nuclear protein expressed in proliferating mammalian cells. It is widely used in cancer histopathology but its functions remain unclear. Here, we show that Ki-67 controls heterochromatin organisation. Altering Ki-67 expression levels did not significantly affect cell proliferation in vivo. Ki-67 mutant mice developed normally and cells lacking Ki-67 proliferated efficiently. Conversely, upregulation of Ki-67 expression in differentiated tissues did not prevent cell cycle arrest. Ki-67 interactors included proteins involved in nucleolar processes and chromatin regulators. Ki-67 depletion disrupted nucleologenesis but did not inhibit pre-rRNA processing. In contrast, it altered gene expression. Ki-67 silencing also had wide-ranging effects on chromatin organisation, disrupting heterochromatin compaction and long-range genomic interactions. Trimethylation of histone H3K9 and H4K20 was relocalised within the nucleus. Finally, overexpression of human or Xenopus Ki-67 induced ectopic heterochromatin formation. Altogether, our results suggest that Ki-67 expression in proliferating cells spatially organises heterochromatin, thereby controlling gene expression.
Topics: Animals; Cell Proliferation; Gene Expression; Gene Knockdown Techniques; Heterochromatin; Humans; Ki-67 Antigen; Mice; Xenopus
PubMed: 26949251
DOI: 10.7554/eLife.13722 -
Journal of Immunology (Baltimore, Md. :... Nov 2016The ability to culture and expand B cells in vitro has become a useful tool for studying human immunity. A limitation of current methods for human B cell culture is the...
The ability to culture and expand B cells in vitro has become a useful tool for studying human immunity. A limitation of current methods for human B cell culture is the capacity to support mature B cell proliferation. We developed a culture method to support the efficient activation and proliferation of naive and memory human B cells. This culture supports extensive B cell proliferation, with ∼10-fold increases following 8 d in culture and 10-fold increases when cultures are split and cultured for 8 more days. In culture, a significant fraction of naive B cells undergo isotype switching and differentiate into plasmacytes. Culture-derived (CD) B cells are readily cryopreserved and, when recovered, retain their ability to proliferate and differentiate. Significantly, proliferating CD B cells express high levels of MHC class II, CD80, and CD86. CD B cells act as APCs and present alloantigens and microbial Ags to T cells. We are able to activate and expand Ag-specific memory B cells; these cultured cells are highly effective in presenting Ag to T cells. We characterized the TCR repertoire of rare Ag-specific CD4 T cells that proliferated in response to tetanus toxoid (TT) presented by autologous CD B cells. TCR Vβ usage by TT-activated CD4 T cells differs from resting and unspecifically activated CD4 T cells. Moreover, we found that TT-specific TCR Vβ usage by CD4 T cells was substantially different between donors. This culture method provides a platform for studying the BCR and TCR repertoires within a single individual.
Topics: Antigen-Presenting Cells; B-Lymphocytes; CD4 Antigens; CD4-Positive T-Lymphocytes; Cell Culture Techniques; Cell Line; Cell Proliferation; Cells, Cultured; Humans; Immunologic Memory; Lymphocyte Activation; Receptors, Antigen, T-Cell; Tetanus Toxoid
PubMed: 27815447
DOI: 10.4049/jimmunol.1502193 -
Nature Immunology May 2023Resident tissue macrophages (RTMs) are differentiated immune cells that populate distinct niches and exert important tissue-supportive functions. RTM maintenance is...
Resident tissue macrophages (RTMs) are differentiated immune cells that populate distinct niches and exert important tissue-supportive functions. RTM maintenance is thought to rely either on differentiation from monocytes or on RTM self-renewal. Here, we used a mouse model of inducible lung interstitial macrophage (IM) niche depletion and refilling to investigate the development of IMs in vivo. Using time-course single-cell RNA-sequencing analyses, bone marrow chimeras and gene targeting, we found that engrafted Ly6C classical monocytes proliferated locally in a Csf1 receptor-dependent manner before differentiating into IMs. The transition from monocyte proliferation toward IM subset specification was controlled by the transcription factor MafB, while c-Maf specifically regulated the identity of the CD206 IM subset. Our data provide evidence that, in the mononuclear phagocyte system, the ability to proliferate is not merely restricted to myeloid progenitor cells and mature RTMs but is also a tightly regulated capability of monocytes developing into RTMs in vivo.
Topics: Animals; Mice; Monocytes; Macrophages; Cell Differentiation; Lung; Cell Proliferation; MafB Transcription Factor
PubMed: 36928411
DOI: 10.1038/s41590-023-01468-3 -
Environmental Microbiology Nov 2022Methanonatronarchaeia represents a deep-branching phylogenetic lineage of extremely halo(alkali)philic and moderately thermophilic methyl-reducing methanogens belonging...
Methanonatronarchaeia represents a deep-branching phylogenetic lineage of extremely halo(alkali)philic and moderately thermophilic methyl-reducing methanogens belonging to the phylum Halobacteriota. It includes two genera, the alkaliphilic Methanonatronarchaeum and the neutrophilic Ca. Methanohalarchaeum. The former is represented by multiple closely related pure culture isolates from hypersaline soda lakes, while the knowledge about the latter is limited to a few mixed cultures with anaerobic haloarchaea. To get more insight into the distribution and ecophysiology of this enigmatic group of extremophilic methanogens, potential activity tests and enrichment cultivation with different substrates and at different conditions were performed with anaerobic sediment slurries from various hypersaline lakes in Russia. Methanonatronarchaeum proliferated exclusively in hypersaline soda lake samples mostly at elevated temperature, while at mesophilic conditions it coexisted with the extremely salt-tolerant methylotroph Methanosalsum natronophilum. Methanonatronarchaeum was also able to serve as a methylotrophic or hydrogenotrophic partner in several thermophilic enrichment cultures with fermentative bacteria. Ca. Methanohalarchaeum did not proliferate at mesophilic conditions and at thermophilic conditions it competed with extremely halophilic and moderately thermophilic methylotroph Methanohalobium, which it outcompeted at a combination of elevated temperature and methyl-reducing conditions. Overall, the results demonstrated that Methanonatronarchaeia are specialized extremophiles specifically proliferating in conditions of elevated temperature coupled with extreme salinity and simultaneous availability of a wide range of C -methylated compounds and H /formate.
Topics: Phylogeny; Euryarchaeota; Methanosarcinaceae; Lakes; Salinity; RNA, Ribosomal, 16S
PubMed: 35726892
DOI: 10.1111/1462-2920.16108 -
The Journal of Allergy and Clinical... Jun 2022Mast cells (MCs) are pleiotropic cells that accumulate in the esophagus of patients with eosinophilic esophagitis (EoE) and are thought to contribute to disease...
BACKGROUND
Mast cells (MCs) are pleiotropic cells that accumulate in the esophagus of patients with eosinophilic esophagitis (EoE) and are thought to contribute to disease pathogenesis, yet their properties and functions in this organ are largely unknown.
OBJECTIVES
This study aimed to perform a comprehensive molecular and spatial characterization of esophageal MCs in EoE.
METHODS
Esophageal biopsies obtained from patients with active EoE, patients with EoE in histologic remission, and individuals with histologically normal esophageal biopsies and no history of esophageal disease (ie, control individuals) were subject to single-cell RNA sequencing, flow cytometry, and immunofluorescence analyses.
RESULTS
This study probed 39,562 single esophageal cells by single-cell RNA sequencing; approximately 5% of these cells were MCs. Dynamic MC expansion was identified across disease states. During homeostasis, TPSAB1AREG resident MCs were mainly detected in the lamina propria and exhibited a quiescent phenotype. In patients with active EoE, resident MCs assumed an activated phenotype, and 2 additional proinflammatory MC populations emerged in the intraepithelial compartment, each linked to a proliferating MKI67 cluster. One proinflammatory activated MC population, marked as KITIL1RL1FCER1A, was not detected in disease remission (termed "transient MC"), whereas the other population, marked as CMA1CTSG, was detected in disease remission where it maintained an activated state (termed "persistent MC"). MCs were prominent producers of esophageal IL-13 mRNA and protein, a key therapeutic target in EoE.
CONCLUSIONS
Esophageal MCs comprise heterogeneous populations with transcriptional signatures associated with distinct spatial compartmentalization and EoE disease status. In active EoE, they assume a proinflammatory state and locally proliferate, and they remain activated and poised to reinitiate inflammation even during disease remission.
Topics: Cell Proliferation; Eosinophilic Esophagitis; Humans; Mast Cells; Sequence Analysis, RNA
PubMed: 35304158
DOI: 10.1016/j.jaci.2022.02.025 -
Journal of Leukocyte Biology Nov 2023Monocytes (Mo) and macrophages (Mφ) play important roles in the function of tissues, organs, and systems of all animals during homeostasis, infection, injury, and... (Review)
Review
Monocytes (Mo) and macrophages (Mφ) play important roles in the function of tissues, organs, and systems of all animals during homeostasis, infection, injury, and disease. For decades, conventional wisdom has dictated that Mo and Mφ are end-stage cells that do not proliferate and that Mφ accumulation in tissues is the result of infiltration of Mo from the blood and subsequent differentiation to Mφ. However, reports from the early 1900s to the present describe evidence of Mo and Mφ proliferation in different tissues and contexts. The purpose of this review is to summarize both historical and current evidence for the contribution of Mφ proliferation to their accumulation in different tissues during homeostasis, infection, injury, and disease. Mφ proliferate in different organs and tissues, including skin, peritoneum, lung, heart, aorta, kidney, liver, pancreas, brain, spinal cord, eye, adipose tissue, and uterus, and in different species including mouse, rat, rabbit, and human. Mφ can proliferate at different stages of differentiation with infiltrating Mo-like cells proliferating in certain inflammatory contexts (e.g. skin wounding, kidney injury, bladder and liver infection) and mature resident Mφ proliferating in other inflammatory contexts (e.g. nematode infection, acetaminophen liver injury) and during homeostasis. The pathways involved in stimulating Mφ proliferation also may be context dependent, with different cytokines and transcription factors implicated in different studies. Although Mφ are known to proliferate in health, injury, and disease, much remains to be learned about the regulation of Mφ proliferation in different contexts and its impact on the homeostasis, injury, and repair of different organs and tissues.
Topics: Humans; Female; Mice; Rats; Animals; Rabbits; Monocytes; Macrophages; Cytokines; Homeostasis; Cell Proliferation
PubMed: 37555460
DOI: 10.1093/jleuko/qiad093 -
The American Journal of Dermatopathology Feb 2021Intravascular proliferations of the skin are clinically heterogeneous and may present with a wide range of clinical features, including violaceous papules, nodules,... (Review)
Review
Intravascular proliferations of the skin are clinically heterogeneous and may present with a wide range of clinical features, including violaceous papules, nodules, plaques, or other unspecific cutaneous lesions. Histopathologically, these conditions are characterized by proliferation of different cell types within the lumina of dermal vessels and endothelial cell hyperplasia. Immunohistochemistry is the best tool to identify the nature of the intravascular proliferating cells and the type of involved vessel. In this review, we analyzed the clinicopathologic and immunohistochemical characteristics of intravascular large cell lymphoma, T-cell and natural killer-cell intravascular large cell lymphoma, intralymphatic variant of CD30+ cutaneous lymphoproliferative disorders, benign atypical intralymphatic CD30+ T-cell proliferation, reactive angioendotheliomatosis, intralymphatic histiocytosis, papillary intralymphatic angioendothelioma or Dabska tumor, glomeruloid hemangioma, papillary hemangioma, intravascular papillary endothelial hyperplasia or Masson phenomenon, and the intralymphatic involvement of Merkel cell carcinoma, cutaneous metastases, and cutaneous angiosarcoma.
Topics: Animals; Blood Vessels; Carcinoma, Merkel Cell; Cell Proliferation; Endothelial Cells; Hemangioendothelioma; Hemangioma; Histiocytosis; Humans; Hyperplasia; Lymphoma, Extranodal NK-T-Cell; Lymphoma, Large B-Cell, Diffuse; Skin; Skin Diseases, Vascular; Skin Neoplasms
PubMed: 32618704
DOI: 10.1097/DAD.0000000000001706