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Cancer Biology and Genetics for Non-Biologists
Published in Trevor F. Cox, Medical Statistics for Cancer Studies, 2022
Your cells have to communicate, and they do not all live in isolation. Cells send and receive messages via signalling molecules. The signals can tell a cell to grow, produce particular proteins, produce a metabolic response or to die (apoptosis). The signals sent and received are usually called ligands and can be molecules, proteins or ions. Signals can be received from other nearby cells or from afar, the four types being, Paracrine signalling: Signalling by nearby cells allowing similar cells to act similarly• Synaptic signalling: Signalling by electrical impulses through nerve cellsAutocrine signalling: Signalling of a cell to itselfEndocrine signalling: Signalling from distant endocrine cells, e.g. the pancreas
Actions of Dopamine on the Skin and the Skeleton
Published in Nira Ben-Jonathan, Dopamine, 2020
The same investigators [21] also used diabetic rats with defective skin healing properties (Figure 11.5). Application of conditioned media harvested from the Ad-MSCs cultured on Dopa-BC, accelerated wound closure in the diabetic rats, enhanced vascularization, and promoted macrophage switching from a proinflammatory M1 to a pro-healing and anti-inflammatory M2 phenotype in the wound bed. The authors concluded that coating with PDA represents an effective method for enhancing the beneficial paracrine function of MSCs. These findings offer a novel strategy for accelerating tissue regeneration by guiding the paracrine-signaling network.
Tissue injury and repair
Published in C. Simon Herrington, Muir's Textbook of Pathology, 2020
At least three types of extracellular signal can initiate these events. First, there are substances that are secreted by the cells themselves, i.e. a cell produces a growth factor together with the relevant receptor and can, therefore, control its own proliferation. This is referred to as autocrine signalling and occurs in epithelial proliferation in skin wounds and in liver regeneration; it is also a feature of some tumours. The second form is where the molecules stimulating proliferation are produced by cells near the target cell. As we shall see, this occurs in the connective tissue response of repair where, for example, growth factors produced by inflammatory cells can stimulate the proliferation of endothelial and mesenchymal cells. This is referred to as paracrine signalling. Finally, substances produced at a distant site, such as a separate organ, and carried by the blood can also control cell proliferation. This is referred to as endocrine signalling (Figure 3.14).
Epicardial transplantation of autologous atrial appendage micrografts: evaluation of safety and feasibility in pigs after coronary artery occlusion
Published in Scandinavian Cardiovascular Journal, 2022
Annu Nummi, Tommi Pätilä, Severi Mulari, Milla Lampinen, Tuomo Nieminen, Mikko I. Mäyränpää, Antti Vento, Ari Harjula, Esko Kankuri
The number of cardiomyocytes in adult heart remains approximately the same during a lifetime [41,42] and the growth in adult mammalian heart occurs in cell size rather than increase in cells. Despite numerous efforts to generate new cardiac muscle cells via stem/progenitor cell technologies, there is no desired outcome. Bin Zhou and colleagues provided evidence that there is no cardiomyocyte producing stem cell population in the adult mammalian heart [43]. Yet there are promising results documented in improvement of LVEF, ventricular remodeling, and reduction of the infarct scar in both preclinical and clinical studies with stem cells [38–45]. With this paradoxical result, further investigations, especially focusing on elucidating the mechanism of action, on cell therapy in heart failure are necessary. The effect and importance of paracrine signaling, different delivery methods, cell sources, and used cell types all need better understanding and more large-scale, randomized trials.
Evaluation of canine bone marrow-derived mesenchymal stem cells for experimental full-thickness cutaneous wounds in a diabetic rat model
Published in Expert Opinion on Biological Therapy, 2021
Deepika Bist, A. M. Pawde, Prakash Kinjavdekar, Reena Mukherjee, K. P. Singh, Med Ram Verma, Khan Sharun, Amit Kumar, Pawan K. Dubey, Divya Mohan, Amit Verma, G. Taru Sharma
The usefulness of MSC in accelerating wound healing in veterinary practice has not been evaluated much despite increasing evidence that MSCs have the potential to differentiate into various types of cells after they enter the microenvironment of a specific tissue (niche). MSCs therapeutically applied to the wound may release soluble factors that stimulate proliferation and migration of the predominant cell types in the wound [18]. Consequently, paracrine signaling has potential beneficial effects on angiogenesis, epithelialization, and fibroblast proliferation during wound repair. Nonetheless, several reports suggest that MSCs differentiate into epidermal keratinocytes, endothelial cells, and pericytes in vivo [34,35]. Furthermore, it has been reported that none of the xenogenic transplanted MSCs proliferated in an uncontrolled manner, and there was no sign of tumor formation in cutaneous tissue [18].
CD73+ extracellular vesicles inhibit angiogenesis through adenosine A2B receptor signalling
Published in Journal of Extracellular Vesicles, 2020
Roberta Angioni, Cristina Liboni, Stephanie Herkenne, Ricardo Sánchez-Rodríguez, Giulia Borile, Elisabetta Marcuzzi, Bianca Calì, Maurizio Muraca, Antonella Viola
Several reports have demonstrated that mesenchymal stromal cells (MSCs) regulate vascular remodelling and angiogenesis through mechanisms not entirely clarified. MSCs have been primary isolated as a non-haemopoietic, tissue culture plastic adherent sub-fraction of bone marrow cells [17]. Nowadays, they are recognized as key players of the haematopoietic stem cell (HSC) niche where they provide structural and environmental support to HSCs. In the bone marrow, MSCs have been identified as perivascular nestin-expressing cells, closely associated with HSCs [18], localized both into the central area of the marrow and in the proximity of the endosteum [18,19]. Intriguingly, multiple studies have demonstrated that bone marrow MSCs, as also MSCs from other sources, modulate the vascular network [20,21]. Accordingly, by inducing neovascularization, transplanted MSCs have been shown to sustain amelioration of ischaemic hindlimb [22], ischaemic brain [23], myocardial infarction [24] and peripheral artery disease (PAD) [25]. A paracrine mechanism seems to drive the angiogenic MSC potential [26]. Indeed, it has been reported that the MSC-conditioned medium is enriched in numerous pro-angiogenic factors, including ANG-1, placental growth factor (PlGF), IL-6, monocyte chemotactic protein-1 (MCP-1), FGF, VEGF, transforming growth factor-β (TGF-β) and platelet-derived growth factor (PDGF), thus sustaining the formation of new vessels both in vitro and in vivo [27]. In addition, the pro-angiogenic effects of MSCs seem to involve their extracellular vesicles (EVs) [28].