Interactions of the Mechanosensitive Channels with Extracellular Matrix, Integrins, and Cytoskeletal Network in Osmosensation

Abstract

Life is maintained in a sea water-like internal environment. The homeostasis of this environment is dependent on osmosensory system translation of hydromineral information into osmotic regulatory machinery at system, tissue and cell levels. In the osmosensation, hydromineral information can be converted into cellular reactions through osmoreceptors, which changes thirst and drinking, secretion of antidiuretic vasopressin (VP), reabsorption of water and salt in the kidneys at systemic level as well as cellular metabolic activity and survival status at tissue level. The key feature of osmosensation is the activation of mechanoreceptors or mechanosensors, particularly transient receptor potential vallinoid (TRPV) and canonical (TRPC) family channels, which increases cytosolic Ca2+ levels, activates osmosensory cells including VP neurons and triggers a series of secondary reactions. TRPV channels are sensitive to both hyperosmotic and hyposmotic stimuli while TRPC channels are more sensitive to hyposmotic challenge in neurons. The activation of TRP channels relies on changes in cell volume, membrane stretch and cytoskeletal reorganization as well as hydration status of extracellular matrix (ECM) and activity of integrins. Different families of TRP channels could be activated differently in response to hyperosmotic and hyposmotic stimuli in different spatiotemporal orders, leading to differential reactions of osmosensory cells. Together, they constitute the osmosensory machinery. The activation of this osmoreceptor complex is also associated with the activity of other osmolarity-regulating organelles, such as water channel protein aquaporins, Na-K-2Cl cotransporters, volume-sensitive anion channels, sodium pump and purinergic receptors in addition to intercellular interactions, typically astrocytic neuronal interactions. In this article, we review our current understandings of the composition of osmoreceptors and the processes of osmosensation.

Neurochemical regulation of the expression and function of glial fibrillary acidic protein in astrocytes

“…Moreover, changes in extracellular ion levels can change intracellular osmolality, ion concentration, volume, and transporter activity (Jiao, Cui, Wang, Li, & Wang, 2017), which also influence the polymerization status of GFAP as previously reviewed (Wang & Parpura, 2018).…”

“…By contrast, increased cytosolic Ca 2+ level following glutamate activation of NMDARs elicits GFAP fiber depolymerization (Heimfarth et al, ). Moreover, changes in extracellular ion levels can change intracellular osmolality, ion concentration, volume, and transporter activity (Jiao, Cui, Wang, Li, & Wang, ), which also influence the polymerization status of GFAP as previously reviewed (Wang & Parpura, ). Clearly, the metabolic activity of GFAP is an integral part of the glia‐neuronal interactions.…”

TAG synthesis and storage under osmotic stress. A requirement for preserving membrane homeostasis in renal cells

“…However, several reports provide experimental data supporting the role of cytoskeleton and integrin proteins in such action. In nervous cells, extracellular matrix (ECM) hydration, ECM-integrin interaction and cytoskeleton rearrangement are involved in osmosensing process [54].…”

“…Following cell shrinkage, a regulatory volume increase (RVI) occurs that includes the increase in cytosolic Ca 2+ (activated-TRPV channels), the activation of mitogen-activated kinases, and the mobilization of aquaporins from vesicles to the membrane. RVI, reduce microtubule-associated TRPV and hyperosmotic activation of osmosensory neurons occurs [54].…”

Central Transient Receptor Potential Vanilloid 4 Contributes to Systemic Water Homeostasis through Urinary Excretion

“…TRPV4 knockout (KO) mice were established by some laboratories. [8][9][10][11] However, because their phenotypes are inconsistent with each other, its role in systemic water homeostasis remains unclear.…”