scholarly journals K15 promoter-driven enforced expression of NKIRAS exhibits tumor suppressive activity against the development of DMBA/TPA-induced skin tumors

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kenji Tago ◽  
Satoshi Ohta ◽  
Chihiro Aoki-Ohmura ◽  
Megumi Funakoshi-Tago ◽  
Miho Sashikawa ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Functional Role ◽  
Ectopic Expression ◽  
Cellular Transformation ◽  
Skin Tumors ◽  
Murine Fibroblasts ◽  
Ras Family ◽  
Cellular Context ◽  
Suppressive Phenotype

AbstractNKIRAS1 and NKIRAS2 (also called as κB-Ras) were identified as members of the atypical RAS family that suppress the transcription factor NF-κB. However, their function in carcinogenesis is still controversial. To clarify how NKIRAS acts on cellular transformation, we generated transgenic mice in which NKIRAS2 was forcibly expressed using a cytokeratin 15 (K15) promoter, which is mainly activated in follicle bulge cells. The ectopic expression of NKIRAS2 was mainly detected in follicle bulges of transgenic mice with NKIRAS2 but not in wild type mice. K15 promoter-driven expression of NKIRAS2 failed to affect the development of epidermis, which was evaluated using the expression of K10, K14, K15 and filaggrin. However, K15 promoter-driven expression of NKIRAS2 effectively suppressed the development of skin tumors induced by treatment with 7,12-dimethylbenz(a)anthracene (DMBA)/12-O-tetradecanoylphorbol 13-acetate (TPA). This observation suggested that NKIRAS seemed to function as a tumor suppressor in follicle bulges. However, in the case of oncogenic HRAS-driven cellular transformation of murine fibroblasts, knockdown of NKIRAS2 expression drastically suppressed HRAS-mutant-provoked cellular transformation, suggesting that NKIRAS2 was required for the cellular transformation of murine fibroblasts. Furthermore, moderate enforced expression of NKIRAS2 augmented oncogenic HRAS-provoked cellular transformation, whereas an excess NKIRAS2 expression converted its functional role into a tumor suppressive phenotype, suggesting that NKIRAS seemed to exhibit a biphasic bell-shaped enhancing effect on HRAS-mutant-provoked oncogenic activity. Taken together, the functional role of NKIRAS in carcinogenesis is most likely determined by not only cellular context but also its expression level.

scholarly journals Host EPAC1 Modulates Rickettsial Adhesion to Vascular Endothelial Cells via Regulation of ANXA2 Y23 Phosphorylation

Pathogens ◽  
2021 ◽  
Vol 10 (10) ◽  
pp. 1307
Author(s):  
Zhengchen Su ◽  
Thomas R. Shelite ◽  
Yuan Qiu ◽  
Qing Chang ◽  
Maki Wakamiya ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Signaling Pathway ◽  
Functional Role ◽  
Vascular Endothelial Cells ◽  
Ectopic Expression ◽  
Intracellular Camp ◽  
Vascular Endothelial ◽  
Initial Adhesion

Introduction: Intracellular cAMP receptor exchange proteins directly activated by cAMP 1 (EPAC1) regulate obligate intracellular parasitic bacterium rickettsial adherence to and invasion into vascular endothelial cells (ECs). However, underlying precise mechanism(s) remain unclear. The aim of the study is to dissect the functional role of the EPAC1-ANXA2 signaling pathway during initial adhesion of rickettsiae to EC surfaces. Methods: In the present study, an established system that is anatomically based and quantifies bacterial adhesion to ECs in vivo was combined with novel fluidic force microscopy (FluidFM) to dissect the functional role of the EPAC1-ANXA2 signaling pathway in rickettsiae–EC adhesion. Results: The deletion of the EPAC1 gene impedes rickettsial binding to endothelium in vivo. Rickettsial OmpB shows a host EPAC1-dependent binding strength on the surface of a living brain microvascular EC (BMEC). Furthermore, ectopic expression of phosphodefective and phosphomimic mutants replacing tyrosine (Y) 23 of ANXA2 in ANXA2-knock out BMECs results in different binding force to reOmpB in response to the activation of EPAC1. Conclusions: EPAC1 modulates rickettsial adhesion, in association with Y23 phosphorylation of the binding receptor ANXA2. Underlying mechanism(s) should be further explored to delineate the accurate role of cAMP-EPAC system during rickettsial infection.

Functional role of ionic regulation of Na+/Ca2+ exchange assessed in transgenic mouse hearts

1999 ◽  
Vol 277 (6) ◽  
pp. H2212-H2221 ◽  
Author(s):  
Krista Maxwell ◽  
Jason Scott ◽  
Alexander Omelchenko ◽  
Anton Lukas ◽  
Liyan Lu ◽  
...  
Keyword(s):  
Transgenic Mice ◽  
Functional Role ◽  
Ionic Regulation ◽  
Patch Clamp Technique ◽  
Physiological Importance ◽  
Regulatory Processes ◽  
Cardiac Contractile ◽  
Primary Mechanism ◽  
Regulatory Properties

Na+/Ca2+exchange is the primary mechanism mediating Ca2+ efflux from cardiac myocytes during diastole and, thus, can prominently influence contractile force. In addition to transporting Na+and Ca2+, the exchanger is also regulated by these ions. Although structure-function studies have identified protein regions of the exchanger subserving these regulatory processes, their physiological importance is unknown. In this study, we examined the electrophysiological and mechanical consequences of cardiospecific overexpression of the canine cardiac exchanger NCX1.1 and a deletion mutant of NCX1.1 (Δ680–685), devoid of intracellular Na+([Formula: see text])- and Ca2+([Formula: see text])- dependent regulatory properties, in transgenic mice. Using the giant excised patch-clamp technique, normal ionic regulation was observed in membrane patches from cardiomyocytes isolated from control and transgenic mice overexpressing NCX1.1. In contrast, ionic regulation was nearly abolished in mice overexpressing Δ680–685, indicating that the native regulatory processes could be overwhelmed by expression of the transgene. To address the physiological consequences of ionic regulation of the Na+/Ca2+exchanger, we examined postrest force development in papillary muscles from NCX1.1 and Δ680–685 transgenic mice. Postrest potentiation was found to be substantially greater in Δ680–685 than in NCX1.1 transgenic mice, supporting the notion that ionic regulation of Na+/Ca2+exchange plays a significant functional role in cardiac contractile properties.

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