Université de Fribourg

Task-dependent changes of corticospinal excitability during observation and motor imagery of balance tasks

Mouthon, Audrey ; Ruffieux, Jean ; Wälchli, Michael ; Keller, Martin ; Taube, Wolfgang

In: Neuroscience, 2015, vol. 303, p. 535–543

Non-physical balance training has demonstrated to be efficient to improve postural control in young people. However, little is known about the potential to increase corticospinal excitability by mental simulation in lower leg muscles. Mental simulation of isolated, voluntary contractions of limb muscles increase corticospinal excitability but more automated tasks like walking seem to have no or...

Université de Fribourg

Arginase iI promotes macrophage inflammatory responses through mitochondrial reactive oxygen species, contributing to insulin resistance and atherogenesis

Ming, Xiu‐Fen ; Rajapakse, Angana G. ; Yepuri, Gautham ; Xiong, Yuyan ; Carvas, João M. ; Ruffieux, Jean ; Scerri, Isabelle ; Wu, Zongsong ; Popp, Katja ; Li, Jianhui ; Sartori, Claudio ; Scherrer, Urs ; Kwak, Brenda R. ; Montani, Jean‐Pierre ; Yang, Zhihong

In: Journal of the American Heart Association, 2012, p. -

Background Macrophage‐mediated chronic inflammation is mechanistically linked to insulin resistance and atherosclerosis. Although arginase I is considered antiinflammatory, the role of arginase II (Arg‐II) in macrophage function remains elusive. This study characterizes the role of Arg‐II in macrophage inflammatory responses and its impact on obesity‐linked type II...

Université de Fribourg

Hyperactive S6K1 mediates oxidative stress and endothelial dysfunction in aging: inhibition by resveratrol

Rajapakse, Angana Gupta ; Yepuri, Gautham ; Carvas, João M. ; Stein, Sokrates ; Matter, Christian M. ; Scerri, Isabelle ; Ruffieux, Jean ; Montani, Jean-Pierre ; Ming, Xiu-Fen ; Yang, Zhihong

In: PLoS ONE, 2011, vol. 6, no. 4, p. e19237

Mammalian target of rapamycin (mTOR)/S6K1 signalling emerges as a critical regulator of aging. Yet, a role of mTOR/S6K1 in aging-associated vascular endothelial dysfunction remains unknown. In this study, we investigated the role of S6K1 in aging-associated endothelial dysfunction and effects of the polyphenol resveratrol on S6K1 in aging endothelial cells. We show here that senescent endothelial...

Université de Fribourg

Opposing and uncoupling effects of mTOR and S6K1 in the regulation of endothelial tissue factor expression

Ming, Xiu-Fen ; Rajapakse, Angana Gupta ; Carvas, João Miguel ; Ruffieux, Jean ; Yang, Zhihong

In: Febs Letters, 2010, vol. 58, no. 1, p. 135-140

Rapamycin has been reported to enhance tissue factor (TF) expression. The present study investigated roles of mammalian target of rapamycin (mTOR) and its downstream S6K1 in this process. We showed here that, consistent with rapamycin, knocking-down mTOR enhanced thrombin-induced TF mRNA and protein levels, whereas silencing S6K1 mitigated up-regulation of TF protein but not TF mRNA level. The...

Université de Fribourg

Inhibition of S6K1 accounts partially for the anti-inflammatory effects of the arginase inhibitor L-norvaline

Ming, Xiu-Fen ; Rajapakse, Angana Gupta ; Carvas, João Miguel ; Ruffieux, Jean ; Yang, Zhihong

In: BMC Cardiovascular Disorders, 2009, vol. 9, no. 12, p. -

Background: Pharmacological inhibition of endothelial arginase-II has been shown to improve endothelial nitric oxide synthase (eNOS) function and reduce atherogenesis in animal models. We investigated whether the endothelial arginase II is involved in inflammatory responses in endothelial cells. Methods: Human endothelial cells were isolated from umbilical veins and stimulated with TNFα (10...

Université de Fribourg

Thrombin Stimulates Human Endothelial Arginase Enzymatic Activity via RhoA/ROCK Pathway

Ming, Xiu-Fen ; Barandier, Christine ; Viswambharan, Hema ; Kwak, Brenda R. ; Mach, François ; Mazzolai, Lucia ; Hayoz, Daniel ; Ruffieux, Jean ; Rusconi, Sandro ; Montani, Jean-Pierre ; Yang, Zhihong

In: Circulation, 2004, vol. 110, p. 3708-3714

Background— Arginase competes with endothelial nitric oxide synthase (eNOS) for the substrate L-arginine and decreases NO production. This study investigated regulatory mechanisms of arginase activity in endothelial cells and its role in atherosclerosis. Methods and Results— In human endothelial cells isolated from umbilical veins, thrombin concentration- and time-dependently stimulated...