Caveolin-1 and Rac regulate endothelial capillary-like tubular formation and fenestral contraction in sinusoidal endothelial cells.

Background/aims: Rho guanidine triphosphatases (GTPases) are major regulators of cell migration. We investigated the cytoskeleton and Rho GTPases during cell migration and morphogenesis processes in isolated rat liver sinusoidal endothelial cells (LSECs) cultured on Matrigel while stimulated by the vascular endothelial growth factor (VEGF).

Methods: To obtain primary monolayers, LSECs were cultured on Matrigel for 5-17 h with or without VEGF.

Vasotocin has the potential to inhibit basolateral Na(+)/K (+)-pump current across isolated skin of tree frog in vitro, via its V(2)-type receptor/cAMP pathway.

Adult frog skin transports Na(+) from the apical to the basolateral side across the skin. Antidiuretic hormone (ADH) is involved in the regulation of Na(+) transport in both mammals and amphibians. We investigated the effect of arginine vasotocin (AVT), the ADH of amphibians, on the short-circuit current (SCC) across intact skin and on the basolateral Na(+)/K(+)-pump current across apically nystatin-permeabilized skin of the tree frog, Hyla japonica, in which the V(2)-type ADH receptor is expressed in vitro.

The endothelin-1 receptor-mediated pathway is not involved in the endothelin-1-induced defenestration of liver sinusoidal endothelial cells.

Background/aims: We previously reported that endothelin (ET)-1 may be involved in the contraction of hepatic sinusoidal endothelial fenestrae (SEF). Rho has emerged as an important regulator of the actin cytoskeleton and consequently cell morphology. To clarify the role of ET receptors [endothelin A receptor (ETAR) and endothelin B receptor (ETBR)] in ET-1-induced defenestration, we studied the size of hepatic SEF under various experimental conditions.

Actin filaments around endothelial fenestrae in rat hepatic sinusoidal endothelial cells.

The presence of microfilaments in the vicinity of sinusoidal endothelial fenestrae (SEF) suggests that the cytoskeleton of liver sinusoidal endothelial cells (LSEC) plays an important role in the modulation of SEF. In this study, we investigated actin filaments around SEF in LSECs. Monolayers of LSEC culture were established by infusing a rat liver with collagenase for 30 min and then culturing in RMPI medium for 24 h.

Sinusoidal endothelial fenestrae organization regulated by myosin light chain kinase and Rho-kinase in cultured rat sinusoidal endothelial cells.

The presence of actin filaments in the neighborhood of sinusoidal endothelial fenestrae (SEF) indicates that the cytoskeleton of sinusoidal endothelial cells (SEC) plays an important role in the modulation of SEF. We examined the roles of Rho-kinase and myosin light chain kinase (MLCK) in the organization of SEF. Cultured SEC were treated with MLCK inhibitor (ML-7) and Rho-kinase inhibitor (Y-27632).

Rho modulates hepatic sinusoidal endothelial fenestrae via regulation of the actin cytoskeleton in rat endothelial cells.

The presence of actin-like microfilaments in the vicinity of sinusoidal endothelial fenestrae (SEF) indicates that the cytoskeleton of sinusoidal endothelial cells (SEC) plays an important role in the modulation of SEF. Rho has emerged as an important regulator of the actin cytoskeleton, and consequently cell morphology. The present study aimed to examine how a Rho stimulator; lysophosphatidic acid (LPA), and a Rho inhibitor; bacterial toxin C3 transferase (C3-transferase), affect the morphology of SEF.

Endothelin-1 suppresses plasma membrane Ca++-ATPase, concomitant with contraction of hepatic sinusoidal endothelial fenestrae.

Intracytoplasmic free calcium ions (Ca++) are maintained at a very low concentration in mammalian tissue by extruding Ca++ from the cytoplasm against a steep extracellular Ca++ concentration gradient, mainly through the activity of plasma membrane Ca++ pump-ATPase. The present study aimed to elucidate how endothelin-1 (ET-1) affects the morphology of sinusoidal endothelial fenestrae and ultrastructural distribution of plasma membrane ATPases and intracytoplasmic free Ca++ in isolated rat hepatic sinusoidal endothelial cells. Sinusoidal endothelial fenestrae were observed by scanning electron microscope.