Regulation of genes encoding proteolytic enzymes during mammary gland development

2005 ◽  
Vol 72 (4) ◽  
pp. 433-441 ◽  
Author(s):  
David A Sorrell ◽  
Malgorzata Szymanowska ◽  
Marion Boutinaud ◽  
Claire Robinson ◽  
Richard WE Clarkson ◽  
...  

The mammary gland undergoes extensive tissue remodelling during each lactation cycle. During pregnancy, the epithelial compartment of the gland is vastly expanded (Benaud et al. 1998). At the end of lactation the epithelial cells undergo apoptosis and adipocyte differentiation is induced (Lilla et al. 2002). Ductal and alveolar growth during puberty and pregnancy, and the involution process require the action of proteolytic enzymes (including matrix metalloproteinases, plasminogen and membrane-peptidases) and the corresponding genes are activated during these periods (Benaud et al. 1998; Alexander et al. 2001). Matrix metalloproteinases (MMP) are expressed in several cell types of the mammary gland including stromal fibroblasts (e.g., MMP3, MMP2), epithelial cells (e.g., MMP7 or MMP9), adipocytes (e.g., MMP2) and lymphoid cells (e.g., MMP9) (Crawford et al. 1996; Lund et al. 1996; Wiseman et al. 2003). A number of knock-out mice, which are deficient for individual MMP genes (e.g., MMP2, MMP3) or plasminogen, display alterations to mammary gland structure and impairment of lactation (Lund et al. 1999; Wiseman et al. 2003).

1986 ◽  
Vol 34 (8) ◽  
pp. 1037-1046 ◽  
Author(s):  
A Sonnenberg ◽  
H Daams ◽  
M A Van der Valk ◽  
J Hilkens ◽  
J Hilgers

The development of the mouse mammary gland was studied immunohistochemically using monoclonal antibodies against cell surface and basement membrane proteins and a polyclonal antibody against keratin. We have identified three basic cell types: basal, myoepithelial, and epithelial cells. The epithelial cells can be subdivided into three immunologically related cell types: luminal type I, luminal type II, and alveolar cells. These five cell types appear at different stages of mammary gland development and have either acquired or lost one of the antibody-defined antigens. The cytoplasmic distribution of several of these antigens varied according to the location of the cells within the mammary gland. Epithelial cells which did not line the lumen expressed antigens throughout the cytoplasm. These antigens were demonstrated on the apical site in situations where the cells lined the lumen. One antigen became increasingly basolateral as the cells became attached to the basement membrane. The basal cells synthesize laminin and deposit it at the cell base. They are present in endbuds and ducts and are probably the stem cells of the mammary gland. Transitional forms have been demonstrated which developmentally link these cells with both myoepithelial and (luminal) epithelial cells.


2020 ◽  
Author(s):  
Fengfei Gu ◽  
Jiajin Wu ◽  
Senlin Zhu ◽  
Teresa G. Valencak ◽  
Jian-Xin Liu ◽  
...  

Abstract Background: Cow’s milk is a highly-nutritious dairy product that is widely consumed worldwide. It is secreted by the developed mammary gland (MG) of dairy cattle. However, a comprehensive understanding of cell-type diversity and cell function within bovine MG is lacking. In the current study, we used single-cell RNA sequencing to investigate the transcriptome of 24,472 high-quality MG cells isolated from newborn and adult cows. Results: Unbiased clustering analysis revealed the existence of 24 cell types, which could be divided into four categories: 9 immune, 3 epithelial, 9 fibroblast, and 3 endothelial cell types. Other cell subtypes were further identified based on re-clustering and pseudotemporal reconstruction of epithelial cells that included 3 mature luminal epithelial, 1 intermediate, and 2 progenitor cell subtypes. The individual top marker genes of these 3 mature luminal epithelial cell subtypes (L0, L1, and L5) were APOA1, STC2, and PTX3, which were further validated using immunofluorescence. Based on functional analysis, the L0, L1, and L5 cell subtypes were all involved in the upregulation of lipid metabolism, protein and hormone metabolism, and the immune response, respectively. Furthermore, we discovered a novel myofibroblast that expresses COL1A1 and CSN3, has visible epithelial-like characteristics, and shows the potential to differentiate into luminal epithelial cells, especially immune-sensing luminal cells (L5). Conclusions: We constructed the first single-cell atlas of the dairy cow MG, and our new findings of epithelial-like myofibroblast cells and their differentiation trajectories into luminal cells may provide novel insights into the development and lactogenesis in dairy cattle MGs.


2001 ◽  
Vol 26 (1) ◽  
pp. 11-19 ◽  
Author(s):  
G Pelletier ◽  
V Luu-The ◽  
M El-Alfy ◽  
S Li ◽  
F Labrie

The subcellular distribution of steroidogenic enzymes has so far been studied mostly in classical endocrine glands and in the placenta. In the peripheral intracrine organs which synthesize sex steroids there is no indication about the organelles which contain the enzymes involved in steroid biosynthesis. We have thus investigated the subcellular localization of two enzymes involved in the production of sex steroids, namely 3beta-hydroxysteroid dehydrogenase (3beta-HSD) and type 5 17beta-hydroxysteroid dehydrogenase (17beta-HSD). Using specific antibodies to these enzymes, we conducted immunoelectron microscopic studies in two peripheral tissues, namely the human prostate and mammary gland. In the prostate, immunolabelling for both 3beta-HSD and type 5 17beta-HSD was detected in the basal cells of the tube-alveoli as well as in fibroblasts and endothelial cells lining the blood vessels. In all the labelled cell types, the gold particles were distributed throughout the cytoplasm. No obvious association with any specific organelle could be observed, although some concentration of gold particles was occasionally found over bundles of microfilaments. In mammary gland sections immunolabelled for 3beta-HSD or type 5 17beta-HSD localization, labelling was observed in the cytoplasm of the secretory epithelial cells in both the acini and terminal ducts. Immunolabelling was also found in the endothelial cells as well as in fibroblasts in stroma and blood vessels. The gold particles were not detected over any organelles, except with the occasional accumulation of gold particles over microfilaments. The present data on the localization of two steroidogenic enzymes leading to the synthesis of testosterone indicate that these enzymes are located not only in epithelial cells but also in stromal and endothelial cells in both tissues studied. The absence of any association of the enzymes with membrane-bound organelles appears as a common finding in the reactive cell types of two peripheral tissues.


1996 ◽  
Vol 44 (9) ◽  
pp. 1033-1042 ◽  
Author(s):  
A Gebert

The tonsil crypt epithelium contains membranous (M)-cells that transport antigens from the lumen to underlying lymphoid cells, thereby initiating specific immune responses. Mechanisms mediating the adhesion of antigens to the M-cell surface are important for effective and selective uptake of potential pathogens but are still poorly understood. Therefore, the carbohydrates present on crypt epithelial cells of the rabbit palatine tonsil were studied by lectin histochemistry. Ultrathin LR White sections were incubated with a panel of eight lectins conjugated to colloidal gold or biotin. The glycocalyx of the apical membrane of M-cells was selectively labeled by UEA-I, LTA, HPA, and VVA, whereas that of the remaining squamous epithelial cells preferentially bound RCA-I and PNA. WGA and ConA showed only little binding, with no discernible preference for any of the cell types. Double labeling of UEA-1 together with anti-vimentin antibodies revealed that UEA-I-positive epithelial cells also contained the rabbit M-cell marker vimentin, and vice versa. The results show that a specific composition of glycoconjugates, which differs from that on squamous epithelial cells, is found on M-cells of the rabbit tonsil. The M-cell-specific glycoproteins and glycolipids could be selectively targeted by microorganisms that adhere to M-cells and enter the host along this pathway.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mickey V. Patel ◽  
Marta Rodriguez-Garcia ◽  
Zheng Shen ◽  
Charles R. Wira

AbstractMucosal integrity in the endometrium is essential for immune protection. Since breaches or injury to the epithelial barrier exposes underlying tissue and is hypothesized to increase infection risk, we determined whether endogenous progesterone or three exogenous progestins (medroxyprogesterone acetate (MPA), norethindrone (NET), and levonorgestrel (LNG)) used by women as contraceptives interfere with wound closure of endometrial epithelial cells and fibroblasts in vitro. Progesterone and LNG had no inhibitory effect on wound closure by either epithelial cells or fibroblasts. MPA significantly impaired wound closure in both cell types and delayed the reestablishment of transepithelial resistance by epithelial cells. In contrast to MPA, NET selectively decreased wound closure by stromal fibroblasts but not epithelial cells. Following epithelial injury, MPA but not LNG or NET, blocked the injury-induced upregulation of HBD2, a broad-spectrum antimicrobial implicated in wound healing, but had no effect on the secretion of RANTES, CCL20 and SDF-1α. This study demonstrates that, unlike progesterone and LNG, MPA and NET may interfere with wound closure following injury in the endometrium, potentially conferring a higher risk of pathogen transmission. Our findings highlight the importance of evaluating progestins for their impact on wound repair at mucosal surfaces.


2021 ◽  
Author(s):  
Phoebe M Kirkwood ◽  
Douglas A Gibson ◽  
Isaac Shaw ◽  
Ross Dobie ◽  
Olympia Kelepouri ◽  
...  

The human endometrium experiences repetitive cycles of tissue wounding characterised by piecemeal shedding of the surface epithelium and rapid restoration of tissue homeostasis. In this study we used a validated mouse model of endometrial repair in combination with three transgenic lines of mice to investigate whether epithelial cells that become incorporated into the newly formed luminal epithelium have their origins in one or more of the mesenchymal cell types present in the stromal compartment of the cycling endometrium. Using scRNAseq we identified a novel population of PDGFRb+ cells that arose in the endometrium in response to endometrial breakdown/repair. These cells expressed genes usually considered specific to epithelial cells and in silico trajectory analysis suggested they arose from stromal fibroblasts and were in transition to becoming epithelial cells. To confirm our hypothesis we used a lineage tracing strategy to compare the fate of stromal fibroblasts (PDGFRa+) and stromal perivascular cells (NG2+). We demonstrate for the first time that stromal fibroblasts can undergo a mesenchyme to epithelial transformation and become incorporated into the re-epithelialised luminal surface of the repaired tissue. This study is the first to discover a novel population of wound-responsive, plastic endometrial stromal fibroblasts that contribute to restoration of tissue integrity during endometrial repair. These findings form a platform for comparisons both to endometrial pathologies which involve a fibrotic response (Ashermans syndrome, endometriosis) as well as other mucosal tissues which have a variable response to wounding.


2019 ◽  
Vol 9 (10) ◽  
pp. 3439-3452 ◽  
Author(s):  
Shawn J. Cokus ◽  
Maricruz De La Torre ◽  
Eric F. Medina ◽  
Jeffrey P. Rasmussen ◽  
Joselyn Ramirez-Gutierrez ◽  
...  

Epithelial cells are the building blocks of many organs, including skin. The vertebrate skin initially consists of two epithelial layers, the outer periderm and inner basal cell layers, which have distinct properties, functions, and fates. The embryonic periderm ultimately disappears during development, whereas basal cells proliferate to form the mature, stratified epidermis. Although much is known about mechanisms of homeostasis in mature skin, relatively little is known about the two cell types in pre-stratification skin. To define the similarities and distinctions between periderm and basal skin epithelial cells, we purified them from zebrafish at early development stages and deeply profiled their gene expression. These analyses identified groups of genes whose tissue enrichment changed at each stage, defining gene flow dynamics of maturing vertebrate epithelia. At each of 52 and 72 hr post-fertilization (hpf), more than 60% of genes enriched in skin cells were similarly expressed in both layers, indicating that they were common epithelial genes, but many others were enriched in one layer or the other. Both expected and novel genes were enriched in periderm and basal cell layers. Genes encoding extracellular matrix, junctional, cytoskeletal, and signaling proteins were prominent among those distinguishing the two epithelial cell types. In situ hybridization and BAC transgenes confirmed our expression data and provided new tools to study zebrafish skin. Collectively, these data provide a resource for studying common and distinguishing features of maturing epithelia.


2006 ◽  
Vol 8 (32) ◽  
pp. 1-15 ◽  
Author(s):  
Christine J. Watson

During pregnancy, there is a massive increase in the number of luminal epithelial cells in the breast, which are destined to become the milk factories after birth. These cells are no longer required when the young are weaned, and are removed in a carefully orchestrated event called involution. In this process, the secretory epithelial cells die and are replaced by adipocytes, which redifferentiate as the epithelium is removed. It is essential that the gland is properly remodelled to a pre-pregnant state so that successful lactation can occur following a subsequent pregnancy. Furthermore, failure to remove unnecessary lactational alveoli during weaning could result in inflammation and tissue damage. Recently, it has been shown that components in the fatty stroma in involuting breast can promote metastasis. Thus, it is important to understand the molecular mechanisms that regulate involution, how these can fail, the consequences of the remodelling process, and how this knowledge can inform us about breast cancer. In this review, I discuss the roles of the JAK–STAT, NF-κB and other signalling pathways in the regulation of apoptosis and tissue remodelling during involution.


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