Purpose: Meningothelial cells (MECs) play a central role in the maintenance of cerebrospinal fluid (CSF) homeostasis and in physiological and pathophysiological processes within the subarachnoid space (SAS) linking them to optic nerve (ON) pathologies. Still, not much is known about their structural properties that might enable MECs to perform specific functions within the ON microenvironment.
Methods: For closer characterization of the structural properties of the human MEC layer in the arachnoid, we performed immunohistological analyses to evaluate the presence of cell-cell interaction markers, namely, markers for tight junctions (JAM1, Occludin, and Claudin 5), gap junctions (Connexin 26 and 43), and desmosomes (Desmoplakin) as well as for water channel marker aquaporin 4 (AQP4) in retrobulbar, midorbital, and intracanalicular human ON sections.
Results: MECs displayed immunopositivity for markers of tight junctions (JAM1, Occludin, and Claudin 5) and gap junctions (Connexin 26 and 43) as well as for AQP4 water channels. However, no immunopositivity was found for Desmoplakin.
Conclusion: MECs are connected tight junctions and gap junctions, and they possess AQP4 water channels. The presence of these proteins emphasizes the important function of MECs within the ON microenvironment as part of the meningeal barrier. Beyond this barrier function, the expression of these proteins by MECs supports a broader role of these cells in signal transduction and CSF clearance pathways within the ON microenvironment.
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http://dx.doi.org/10.3389/fneur.2017.00308 | DOI Listing |
Acta Histochem Cytochem
December 2024
Department of Cell and Systems Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu 807-8555, Japan.
Cell-to-cell communications are desirable for efficient functioning in endocrine cells. Gap junctions and paracrine factors are major mechanisms by which neighboring endocrine cells communicate with each other. The current experiment was undertaken to morphologically examine gap junction expression and developmental changes in rat adrenal medullary chromaffin (AMC) cells.
View Article and Find Full Text PDFElife
January 2025
Department of Brain Sciences, Daegu Gyeongbuk Institute of Science and Technology, Daegu, Republic of Korea.
Recent experimental studies showed that electrically coupled neural networks like in mammalian inferior olive nucleus generate synchronized rhythmic activity by the subthreshold sinusoidal-like oscillations of the membrane voltage. Understanding the basic mechanism and its implication of such phenomena in the nervous system bears fundamental importance and requires preemptively the connectome information of a given nervous system. Inspired by these necessities of developing a theoretical and computational model to this end and, however, in the absence of connectome information for the inferior olive nucleus, here we investigated interference phenomena of the subthreshold oscillations in the reference system for which the structural anatomical connectome was completely known recently.
View Article and Find Full Text PDFCancers (Basel)
December 2024
School of Medicine, Università Cattolica del Sacro Cuore, 00168 Rome, Italy.
Connexin-43 (Cx43) is the most characterized gap junction protein, primarily involved in the Gap Junctional Intercellular Communication (GJIC) between adjacent cells to facilitate molecule exchange and the formation of a signaling network. It is increasingly evident that the importance of Cx43 is not only limited to its GJIC function, but rather includes its role in connecting the intracellular and extracellular environment by forming membrane hemichannels, as well as its intracellular signaling function mediated by its C-terminal tail (Cx43-CT). Notably, Cx43 has been implicated in a variety of cancers, with earlier notions suggesting a tumor-suppressor function, whereas new studies shed light on its pro-tumorigenic role.
View Article and Find Full Text PDFBackground: Patients with arrhythmogenic cardiomyopathy (ACM) due to pathogenic variants in , the gene for the desmosomal protein plakophilin-2, are being enrolled in gene therapy trials designed to replace the defective allele via adeno-associated viral (AAV) transduction of cardiac myocytes. Evidence from experimental systems and patients indicates that ventricular myocytes in ACM have greatly reduced electrical coupling at gap junctions and reduced Na current density. In previous AAV gene therapy trials, <50% of ventricular myocytes have generally been transduced.
View Article and Find Full Text PDFBackground: Juxtaglomerular (JG) cells are sensors that control blood pressure and fluid-electrolyte homeostasis. In response to a decrease in perfusion pressure or changes in the composition and/or volume of the extracellular fluid, JG cells release renin, which initiates an enzymatic cascade that culminates in the production of angiotensin II (Ang II), a potent vasoconstrictor that restores blood pressure and fluid homeostasis. In turn, Ang II exerts a negative feedback on renin release, thus preventing excess circulating renin and the development of hypertension.
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