Fibroblast-Pneumonocyte Factor
Jason Kelley in Cytokines of the Lung, 2022
Many organs are composed of two different tissues, epithelium and mesenchyme. Mutual interactions of these two tissues have been demonstrated to be essential for the sequential events of organogenesis—determination, growth, morphogenesis, and cytodifferentiation (Bissell et al., 1982; Grobstein, 1967; Karkinen-Jaakelainen et al., 1977; Lash and Whittaker, 1974; Lash and Burger, 1977; Poste and Nicolson, 1977; Saxen, 1977; Wessels, 1977). The concept that these associated cell components act on each other to generate new and diverse cell types during organogenesis was initially termed embryonic induction (Grobstem, 1967), but it is now referred to as tissue interaction. In 1911, Peebles had already suggested that tissue interaction might play a very important role in organogenesis. Since Grobstein first demonstrated in 1953 the necessity of epithelial-mesenchymal interactions in the morphogenesis of various organs, many examples of such interactions have been described. Mesenchyme seems to play a predominant role in directing differentiation. These mesenchymal inductions have been classified into two types, inductive and permissive direction (Saxen, 1977), and the respective cellular responses are termed commitment and progression.
The Many Faces of Neoplasia
Jeremy R. Jass in Understanding Pathology, 2020
The term sarcoma refers to a cancer arising from mesenchymal tissue. The prototypic mesenchymal derivative is connective tissue, the supporting layer that underlies epithelia and surrounds ducts. This kind of connective tissue (or stroma) has a loose texture because the cells (fibroblasts) are widely scattered in a mucoid matrix that includes collagen fibres that are secreted by the fibroblasts. Cancers arising in such tissue may be termed fibrosarcomas and are characterised by the presence of collagen fibres. However, the term connective tissue can be broadened to encompass more specialised types of tissue of mesenchymal origin, including muscle, fat and bone. It is very unusual for adult skeletal muscle to become malignant, but the smooth muscle found in the gut, walls of blood vessels or uterus (over which we have no voluntary control) may give rise to cancers. Cancers of smooth muscle, fat and bone are called leiomyosarcomas, liposarcomas and osteosarcomas respectively. The benign equivalents are leiomyomas, lipomas and osteomas (Table 7). Many sarcomas are white and soft on sectioning, rather like the flesh of fish.
Pathogenesis: Molecular mechanisms of osteoporosis
Peter V. Giannoudis, Thomas A. Einhorn in Surgical and Medical Treatment of Osteoporosis, 2020
The bone tissue displays important functions in vertebrates that include the protection of vital organs and hematopoietic marrow, the support of muscles, and the storage and release of vital ions such as calcium. The bone tissue is a type of mesenchymal tissue. In the human body, there are two types of bone tissue: cortical and trabecular. The cortical bone represents 80% of the skeleton, while the trabecular bone the remaining 20%. The cortical tissue is found predominantly in the long bones. However, trabecular tissue is found in the central part of the epiphysis of long bones. Trabecular tissue outweighs the flat bones of the pelvis and the vertebrae and is coated in its surface of a cortical tissue layer. The major types of bone tissue cells are osteoblasts, osteoclasts, and osteocytes. We also distinguish organic and inorganic phases in bones. The organic phase includes type I collagen (90%), proteoglycans, and non-collagenous proteins. The organic phase constitutes one-third of bone mass. The inorganic phase comprises calcium salts in the form of hydroxyapatite crystals and constitutes two-thirds of bone mass (19).
Stem cell therapy for salivary gland regeneration after radiation injury
Published in Expert Opinion on Biological Therapy, 2023
Akshaya Upadhyay, Simon D Tran
Given the complexity of radiation damage and its repair process, it is a prerequisite to understand the mechanisms involved in regeneration since stem cell action can be multifactorial. Developmental processes can give valuable cues and help identify regenerative cellular and molecular targets. Careful studies over the years have been instrumental in deciphering these mechanisms for the three principal components of SGs, namely the mesenchyme, the ductal, and acinar system using in vivo [3], ex vivo [4], as well as organoid models [5] (Table 1). An elaborate discussion can be found in work by Chibly et al. [6]. We can conclude that while the epithelial structures (acinar and ductal system) are mainly involved in the gland’s functioning, the mesenchyme has an indispensable role in its physio-pathological response. Therefore, mesenchyme-specific genes and proteins become an essential toolkit in regenerative medicine, adjuvant to epithelial-specific factors. Various supporting cells like vascular, neural, or immune-specific cells and related pathways are also recognized to play a developmental and reparative role in SGs.
Proteomic study of mesothelial and endothelial cross-talk: key lessons
Published in Expert Review of Proteomics, 2022
Juan Manuel Sacnun, Rebecca Herzog, Klaus Kratochwill
Mesothelial cells (MCs) represent the uppermost cell layer lining the peritoneum, pleura, and pericardium, thus the ones exposed to luminal fluids such as peritoneal dialysis (PD) fluids, intraperitoneal chemotherapeutic agents, and ascites. MCs are derived from the mesoderm presenting both epithelial and mesenchymal characteristics. They form a monolayer, the mesothelium, serving as lubricated protective barrier for intraperitoneal and thoracic organs [1–3]. However, the mesothelium has a wide range of functions including cytokine production, transport, inflammation mediation, and coagulation [4–16]. In research focusing on (non-mesothelioma) mesothelium, different cells are used ranging from immortalized human pleural (MeT-5A) and peritoneal (HMRSV5) cell lines to primary MC isolated from omentum, effluent, pericardial, or pleural tissue from humans or animals.
Cross talk between exosomes and pancreatic β-cells in diabetes
Published in Archives of Physiology and Biochemistry, 2022
Mesenchymal stem cells are a type of pluripotent stem cells that have the potential for proliferation and renewal and multi-directional differentiation (Phinney and Pittenger 2017). MSCs have shown excellent therapeutic potential in a variety of animal disease models. Previously, it was thought that the strong tissue repair ability of stem cells came from its differentiation ability (Squillaro et al.2016). However, recent studies have found that the process of repairing tissues is achieved through paracrine actions, and exosomes are one of the main factors of paracrine signalling (S. Zhang et al.2018). Analysis of MSC-derived exosomes (MSC-exo) in animal inflammation models shows that MSC-exos have immunoregulatory and tissue repair functions (Lai et al.2010, Lee et al.2013, Doeppner et al.2015).
Related Knowledge Centers
- Bone
- Epithelium
- Reticular Fiber
- Blood
- Cellular Differentiation
- Connective Tissue
- Skin
- Animal Embryonic Development
- Ground Substance
- Matrix