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Macrophages and Their Potential Role in Hyperreactive Airways Disease
Published in Devendra K. Agrawal, Robert G. Townley, Inflammatory Cells and Mediators in Bronchial Asthma, 2020
Histopathological examination of the airways of individuals who have died from an exacerbation of their asthma characteristically demonstrates exfoliation of epithelial cells, in addition to mucous plugging, basement membrane thickening, and smooth muscle hypertrophy.97 The causes of this disruption of the epithelial cells undoubtedly are multifactorial. Eosinophil products such as major basic protein are one likely culprit; macrophages and their products may be another.
Immune function of epithelial cells
Published in Phillip D. Smith, Richard S. Blumberg, Thomas T. MacDonald, Principles of Mucosal Immunology, 2020
Richard S. Blumberg, Wayne Lencer, Arthur Kaser, Jerrold R. Turner
The mucosal surfaces that support solute, ion, water, and gas transport are typically lined by a delicate single layer of epithelial cells, i.e., a simple epithelium. The epithelial cells present are typically columnar or cuboidal in shape, although they can assume flattened, squamous-like morphologies in the context of migration and wound repair. All epithelial cells lining mucosal surfaces are colonized with commensal organisms of different types and densities depending on the organ system and the location within that system. The commensal organisms have the common properties of resisting the invasion of potential pathogens, modifying luminal microbial composition, regulating mucosal immune cells, and permitting controlled sampling of antigenic materials for interpretation by the immune system.
Tissue injury and repair
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
When tissues are injured there is damage not only to the epithelial cells but also to the surrounding matrix. Therefore, there needs to be restoration not only of the epithelial mass but also of the normal structural framework. It follows that, in all forms of repair, there is at least some connective tissue response. As noted above, the balance between regeneration and connective tissue response is influenced by several factors, including the severity and duration of the injury.
Microbiota, not host origin drives ex vivo intestinal epithelial responses
Published in Gut Microbes, 2022
Kaline Arnauts, Padhmanand Sudhakar, Sare Verstockt, Cynthia Lapierre, Selina Potche, Clara Caenepeel, Bram Verstockt, Jeroen Raes, Séverine Vermeire, João Sabino, Catherine Verfaillie, Marc Ferrante
Epithelial cells from UC patients possess intrinsic defects, both in presence or absence of inflammatory stimuli.12,13 In this study, we examined if the epithelium from UC patients is more sensitive toward microbiota stimulation, compared to the epithelium from non-IBD controls. We also studied if different types of microbiota (balanced vs. dysbiosis) exert distinct effects on epithelial cells. Using organoid-derived monolayer cultures, no pronounced difference between the epithelium from UC patients and non-IBD controls after exposure to microbiota (balanced or dysbiosis) was seen. In contrast, compared to stimulation with microbiota from a healthy volunteer, exposure to microbiota from UC patients induced a damaged and stress induced phenotype in inflamed epithelial cells from UC patients. Expression of key genes was also confirmed in (non-) inflamed non-IBD epithelial cells.
Dysfunction of epithelial permeability barrier induced by HMGB1 in 2.5D cultures of human epithelial cells
Published in Tissue Barriers, 2022
Takashi Kojima, Yuma Shindo, Takumi Konno, Yuki Kodera, Wataru Arai, Maki Miyakawa, Kizuku Ohwada, Hiroki Tanaka, Mitsuhiro Tsujiwaki, Yuji Sakuma, Shin Kikuchi, Tsuyoshi Ohkuni, Kenichi Takano, Atsushi Watanabe, Takayuki Kohno
The airways are broadly classified into conducting and respiratory regions. The conducting airways consist of the trachea, bronchi, and bronchioles, while respiratory regions consist of respiratory bronchioles and alveoli. The conducting airways are lined by a continuous layer of bronchiolar epithelial cells, which act as a first barrier for inhaled materials and play an important role in protection from external pathogens such as bacteria, viruses, chemical substances and allergic components.23,24 On the other hand, alveolar epithelial cells, which are vital for gas exchanges, form a barrier for an air-liquid interface.25 To maintain the air-liquid interface and control gas exchanges, alveolar epithelial cells provide a proper permeability barrier.26 The main characteristic of epithelial tissues is that epithelial cells are arranged in monolayers or stratified layers and tightly adhere to each other. This sheet-like structure provides a barrier function that separates the apical and basolateral compartments of various tissues, and maintains homeostasis.
Ovarian steroids and cancer: news on the breast, questions on the reproductive tract
Published in Gynecological Endocrinology, 2021
Juan J. Hidalgo-Mora, Juan J. Tarín, Antonio Cano
The receptor activator of nuclear factor kappa B (RANK), and its ligand, RANKL, are members of the tumor necrosis factor (TNF) superfamily of cytokines. The RANKL/RANK system participates in several functions in the body, involving among others the immunological system and osteoclast differentiation in bone marrow progenitors [7]. A series of studies in rodents have shown that RANKL/RANK are essential for the development of lobulo-alveolar mammary structures, and that silencing the RANK gene in knockout mice is associated with defective proliferation and increased apoptosis of mammary cells [8]. Along the same lines, animal models overexpressing RANK and RANKL showed increased epithelial proliferation [9]. Evidence rapidly emerged that progesterone binding to the PR in the breast luminal epithelium is followed by both direct proliferation of those cells and increased RANKL synthesis. This cytokine behaves as a proliferative agent for neighboring cells lacking PR. Hence, a double effect is observed, with direct proliferative action on PR-expressing cells, and paracrine action mediated by synthesized RANKL in adjacent cells without PR expression [10]. The increased proliferation rate of epithelial cells paves the way for progression to in situ and invasive cancer in under favorable conditions such as the presence of a carcinogen or genetic lesion. This mechanism, already reviewed in the journal [11], is crucial to understanding progestogen-mediated carcinogenesis.