Epigenetically regulated digital signaling defines epithelial innate immunity at the tissue level

AbstractTo prevent damage to the host or its commensal microbiota, epithelial tissues must match the intensity of the immune response to the severity of a biological threat. Toll-like receptors allow epithelial cells to identify microbe associated molecular patterns. However, the mechanisms that mitigate biological noise in single cells to ensure quantitatively appropriate responses remain unclear. Here we address this question using single cell and single molecule approaches in mammary epithelial cells and primary organoids. We find that epithelial tissues respond to bacterial microbe associated molecular patterns by activating a subset of cells in an all-or-nothing (i.e. digital) manner. The maximum fraction of responsive cells is regulated by a bimodal epigenetic switch that licenses the TLR2 promoter for transcription across multiple generations. This mechanism confers a flexible memory of inflammatory events as well as unique spatio-temporal control of epithelial tissue-level immune responses. We propose that epigenetic licensing in individual cells allows for long-term, quantitative fine-tuning of population-level responses.

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Pulses and delays, anticipation and memory: seeing bacterial stress responses from a single-cell perspective

FEMS Microbiology Reviews ◽

10.1093/femsre/fuaa022 ◽

2020 ◽

Vol 44 (5) ◽

pp. 565-571

Author(s):

Valentine Lagage ◽

Stephan Uphoff

Keyword(s):

Stress Response ◽

Single Cell ◽

Single Molecule ◽

Stress Responses ◽

Phenotypic Diversity ◽

Single Cells ◽

Super Resolution ◽

Population Level ◽

Protective Mechanisms ◽

Single Cell Imaging

ABSTRACT Stress responses are crucial for bacteria to survive harmful conditions that they encounter in the environment. Although gene regulatory mechanisms underlying stress responses in bacteria have been thoroughly characterised for decades, recent advances in imaging technologies helped to uncover previously hidden dynamics and heterogeneity that become visible at the single-cell level. Despite the diversity of stress response mechanisms, certain dynamic regulatory features are frequently seen in single cells, such as pulses, delays, stress anticipation and memory effects. Often, these dynamics are highly variable across cells. While any individual cell may not achieve an optimal stress response, phenotypic diversity can provide a benefit at the population level. In this review, we highlight microscopy studies that offer novel insights into how bacteria sense stress, regulate protective mechanisms, cope with response delays and prepare for future environmental challenges. These studies showcase developments in the single-cell imaging toolbox including gene expression reporters, FRET, super-resolution microscopy and single-molecule tracking, as well as microfluidic techniques to manipulate cells and create defined stress conditions.

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Two novel XRE-like transcriptional regulators control phenotypic heterogeneity in Photorhabdus luminescens cell populations

BMC Microbiology ◽

10.1186/s12866-021-02116-2 ◽

2021 ◽

Vol 21 (1) ◽

Author(s):

Simone Eckstein ◽

Jannis Brehm ◽

Michael Seidel ◽

Mats Lechtenfeld ◽

Ralf Heermann

Keyword(s):

Single Cells ◽

Regulation Of Gene Expression ◽

Transcriptional Regulators ◽

Switching Process ◽

Fine Tuning ◽

Phenotypic Switching ◽

Regulation Mechanism ◽

Photorhabdus Luminescens ◽

Promoter Regions ◽

Epigenetic Switch

Abstract Background The insect pathogenic bacterium Photorhabdus luminescens exists in two phenotypically different forms, designated as primary (1°) and secondary (2°) cells. Upon yet unknown environmental stimuli up to 50% of the 1° cells convert to 2° cells. Among others, one important difference between the phenotypic forms is that 2° cells are unable to live in symbiosis with their partner nematodes, and therefore are not able to re-associate with them. As 100% switching of 1° to 2° cells of the population would lead to a break-down of the bacteria’s life cycle the switching process must be tightly controlled. However, the regulation mechanism of phenotypic switching is still puzzling. Results Here we describe two novel XRE family transcriptional regulators, XreR1 and XreR2, that play a major role in the phenotypic switching process of P. luminescens. Deletion of xreR1 in 1° or xreR2 in 2° cells as well as insertion of extra copies of xreR1 into 2° or xreR2 into 1° cells, respectively, induced the opposite phenotype in either 1° or 2° cells. Furthermore, both regulators specifically bind to different promoter regions putatively fulfilling a positive autoregulation. We found initial evidence that XreR1 and XreR2 constitute an epigenetic switch, whereby XreR1 represses xreR2 expression and XreR2 self-reinforces its own gene by binding to XreR1. Conclusion Regulation of gene expression by the two novel XRE-type regulators XreR1 and XreR2 as well as their interplay represents a major regulatory process in phenotypic switching of P. luminescens. A fine-tuning balance between both regulators might therefore define the fate of single cells to convert from the 1° to the 2° phenotype.

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The 1996 Veylien Henderson Award of the Society of Toxicology of Canada. Current concepts: neutrophils and the activation of carcinogens in the breast and other organs

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y98-083 ◽

1998 ◽

Vol 76 (7-8) ◽

pp. 693-700 ◽

Cited By ~ 10

Author(s):

P David Josephy ◽

Brenda L Coomber

Keyword(s):

Mammary Gland ◽

Epithelial Cells ◽

Chemical Carcinogenesis ◽

Reactive Species ◽

Epithelial Tissue ◽

Chemical Carcinogens ◽

Tissue Inflammation ◽

Epithelial Tissues

Many chemical carcinogens target epithelial tissues, but the biological and biochemical bases of carcinogen specificity remain largely unknown. Focusing on the mammary gland, we discuss the concept that neutrophils metabolize carcinogens to reactive species that damage adjacent epithelial cells. This mechanism may help to explain why epithelial cells are sensitive targets for chemical carcinogenesis, despite their limited bioactivation capacity.Key words: carcinogenesis, neutrophil, bioactivation, peroxidase, epithelial tissue, inflammation.

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Single cell transcriptome atlas of mouse mammary epithelial cells across development

Breast Cancer Research ◽

10.1186/s13058-021-01445-4 ◽

2021 ◽

Vol 23 (1) ◽

Author(s):

Bhupinder Pal ◽

Yunshun Chen ◽

Michael J. G. Milevskiy ◽

François Vaillant ◽

Lexie Prokopuk ◽

...

Keyword(s):

Epithelial Cells ◽

Single Cell ◽

Developmental Stages ◽

Mammary Epithelial Cells ◽

Expression Profiles ◽

Single Cells ◽

Chromatin Accessibility ◽

Mammary Epithelial ◽

Cell Transcriptome ◽

Single Cell Transcriptome

Abstract Background Heterogeneity within the mouse mammary epithelium and potential lineage relationships have been recently explored by single-cell RNA profiling. To further understand how cellular diversity changes during mammary ontogeny, we profiled single cells from nine different developmental stages spanning late embryogenesis, early postnatal, prepuberty, adult, mid-pregnancy, late-pregnancy, and post-involution, as well as the transcriptomes of micro-dissected terminal end buds (TEBs) and subtending ducts during puberty. Methods The single cell transcriptomes of 132,599 mammary epithelial cells from 9 different developmental stages were determined on the 10x Genomics Chromium platform, and integrative analyses were performed to compare specific time points. Results The mammary rudiment at E18.5 closely aligned with the basal lineage, while prepubertal epithelial cells exhibited lineage segregation but to a less differentiated state than their adult counterparts. Comparison of micro-dissected TEBs versus ducts showed that luminal cells within TEBs harbored intermediate expression profiles. Ductal basal cells exhibited increased chromatin accessibility of luminal genes compared to their TEB counterparts suggesting that lineage-specific chromatin is established within the subtending ducts during puberty. An integrative analysis of five stages spanning the pregnancy cycle revealed distinct stage-specific profiles and the presence of cycling basal, mixed-lineage, and 'late' alveolar intermediates in pregnancy. Moreover, a number of intermediates were uncovered along the basal-luminal progenitor cell axis, suggesting a continuum of alveolar-restricted progenitor states. Conclusions This extended single cell transcriptome atlas of mouse mammary epithelial cells provides the most complete coverage for mammary epithelial cells during morphogenesis to date. Together with chromatin accessibility analysis of TEB structures, it represents a valuable framework for understanding developmental decisions within the mouse mammary gland.

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Absolute Quantification of Protein Copy Number in Single Cells With Immunofluorescence Microscopy Calibrated Using Single-Molecule Microarrays

Analytical Chemistry ◽

10.1021/acs.analchem.0c05177 ◽

2021 ◽

Vol 93 (17) ◽

pp. 6656-6664

Author(s):

Stelios Chatzimichail ◽

Pashiini Supramaniam ◽

Ali Salehi-Reyhani

Keyword(s):

Single Molecule ◽

Copy Number ◽

Immunofluorescence Microscopy ◽

Single Cells ◽

Absolute Quantification

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High-Coordinate Mononuclear Ln(III) Complexes: Synthetic Strategies and Magnetic Properties

Magnetochemistry ◽

10.3390/magnetochemistry7010001 ◽

2020 ◽

Vol 7 (1) ◽

pp. 1

Author(s):

Joydev Acharya ◽

Pankaj Kalita ◽

Vadapalli Chandrasekhar

Keyword(s):

Magnetic Properties ◽

Single Molecule ◽

Fine Tuning ◽

Coordination Geometry ◽

Single Molecule Magnets ◽

Magnetization Relaxation ◽

Quantum Tunneling Of Magnetization ◽

Structural Correlation ◽

High Coordination Number ◽

High Coordination

Single-molecule magnets involving monometallic 4f complexes have been investigated extensively in last two decades to understand the factors that govern the slow magnetization relaxation behavior in these complexes and to establish a magneto-structural correlation. The prime goal in this direction is to suppress the temperature independent quantum tunneling of magnetization (QTM) effect via fine-tuning the coordination geometry/microenvironment. Among the various coordination geometries that have been pursued, complexes containing high coordination number around Ln(III) are sparse. Herein, we present a summary of the various synthetic strategies that were used for the assembly of 10- and 12-coordinated Ln(III) complexes. The magnetic properties of such complexes are also described.

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Effects of bone morphogenetic proteins on epithelial repair

Experimental Biology and Medicine ◽

10.1177/15353702211028193 ◽

2021 ◽

pp. 153537022110281

Author(s):

Yu Hou ◽

Yu-Xi He ◽

Jia-Hao Zhang ◽

Shu-Rong Wang ◽

Yan Zhang

Keyword(s):

Growth Factors ◽

Epithelial Cells ◽

Bone Morphogenetic Proteins ◽

Epithelial Tissue ◽

Epithelial Repair ◽

Multiple Functions ◽

Epithelial Damage ◽

Damage Repair ◽

And Migration ◽

Proliferation And Migration

Epithelial tissue has important functions such as protection, secretion, and sensation. Epithelial damage is involved in various pathological processes. Bone morphogenetic proteins (BMPs) are a class of growth factors with multiple functions. They play important roles in epithelial cells, including in differentiation, proliferation, and migration during the repair of the epithelium. This article reviews the functions and mechanisms of the most profoundly studied BMPs in the process of epithelial damage repair and their clinical significance.

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In vitro and in vivo pathologic effects of Vibrio parahaemolyticus on human epithelial cells

Canadian Journal of Microbiology ◽

10.1139/m84-056 ◽

1984 ◽

Vol 30 (3) ◽

pp. 381-388 ◽

Cited By ~ 6

Author(s):

B. R. Merrell ◽

R. I. Walker ◽

S. W. Joseph

Keyword(s):

Epithelial Cells ◽

Epithelial Tissue ◽

Ileal Mucosa ◽

Cytotoxic Factor ◽

Culture Cells ◽

Vibrio Parahemolyticus ◽

Buccal Epithelial Cells ◽

Culture Supernate

The initial interaction and adherence of Vibrio parahemolyticus to epithelial tissue culture cells, human buccal epithelial cells, and the ileal mucosa of mice were studied. Using scanning electron microscopy, adherent bacteria were observed only on degenerating human embryonic intestinal, HeLa, and buccal cells; healthy normal cells were devoid of bacteria. Sheared V. parahaemolyticus, i.e., lacking flagella, did not adhere to either normal or degenerating tissue cells. Neither ultraviolet-inactivated organisms nor cell-free culture supernate affected the epithelial cells. Similar findings were observed on the mucosa of the ileum in mice inoculated with V. parahaemolyticus. It appears that V. parahaemolyticus possesses a cytotoxic factor which alters epithelial cells. This factor appears to be closely associated with viable organisms and may be a functional element in the adherence process of flagellated V. parahaemolyticus to mammalian epithelial cells.

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