Posttransplantation Therapeutic Rapamycin Concentration Protects Nitric Oxide–Related Vascular Endothelial Function: Comparative Effects in Rat Thoracic Aorta and Coronary Endothelial Cell Culture

Wang

Mediators of Inflammation

et al. 2014

Background. Studies indicate the dramatic reduction of shear stress (SS) within the rapamycin eluting stent (RES) segment of coronary arteries. It remains unclear about the role of rapamycin in endothelialization of stented arteries where SS becomes low. Since mTOR (mammalian target of rapamycin) pathway is involved in the antioxidative sestrins expression, we hypothesized that rapamycin attenuated low SS (LSS) induced endothelial dysfunction through mTOR and sestrin1 associated redox regulation. Methods and Results. To mimic the effect of LSS on the stented arteries, a parallel plate flow chamber was used to observe the interplay of LSS and rapamycin on endothelial cells (ECs). The results showed LSS significantly induced EC apoptosis which was mitigated by pretreatment of rapamycin. Rapamycin attenuated LSS induced reactive oxygen species (ROS) and reactive nitrogen species (RNS) production via prohibition of sestrin1 downregulation. Activities of mTORC1 and mTORC2 were detected contradictorily modulated by LSS. Inhibition of rictor expression by target small interfering RNA (siRNA) transfection prohibited sestrin1 downregulation induced by LSS, but inhibition of raptor did not. Conclusions. Rapamycin may prohibit sestrin1 downregulation through targeting mTORC2 in appeasing LSS induced EC oxidative apoptosis. Our results provide the in vitro evidence to explain the pathophysiology of RES stented arteries.

Section: Discussionsupporting

confidence: 82%

Rapamycin Attenuates Endothelial Apoptosis Induced by Low Shear Stress via mTOR and Sestrin1 Related Redox Regulation

Wang

Mediators of Inflammation

et al. 2014

“…The results of the present study indicate that rapamycin also protects against cell death induced by SNP and inhibits sGAG loss induced by IL‐1α. Several studies demonstrated that rapamycin decreased inducible NO synthase protein expression in coronary endothelial cells (50) and inhibited IL‐1β–induced matrix metalloproteinase 9 expression in rat mesangial cells (51). Furthermore, since apoptosis is one of the main features of OA cartilage, we tested the effects of rapamycin against the apoptosis inducer TNFα plus actinomycin D (38).…”

Section: Discussionmentioning

confidence: 99%

Mechanical injury suppresses autophagy regulators and pharmacologic activation of autophagy results in chondroprotection

Caramés¹,

Taniguchi²,

Seino³

et al. 2012

Arthritis & Rheumatism

125

108

Objective Mechanical injury induces cell death in cartilage and triggers a remodeling process that ultimately can manifest as osteoarthritis (OA). Autophagy is a process for turnover of intracellular organelles and macromolecules that protects cells during stress responses. This study determined changes and functions of autophagy following mechanical injury to cartilage. Methods Bovine and human cartilage explants were subjected to mechanical impact (40% strain, 500 ms). Cell viability, sulfated glycosaminoglyan (sGAG) release and changes in autophagy markers ULK1, Beclin1 and LC3 were evaluated. Cartilage explants were also treated with the mTORC1 inhibitor and autophagy inducer rapamycin and tested for protective effects against mechanical injury, the cell death inducers nitric oxide and TNFα+Actinomycin D and the proinflammatory cytokine IL-1α. Results Mechanical injury induced cell death and loss of sGAG in a time-dependent manner. This was associated with significantly decreased ULK1, Beclin1 and LC3 expression in the cartilage superficial zone (P < 0.05) at 48 hours post-injury. The levels of LC3-II were increased at 24 hours post-injury but decreased at 48 and 96 hours. Rapamycin enhanced expression of autophagy regulators and prevented cell death and sGAG loss in mechanically injured explants. Rapamycin also protected against cell death induced by SNP, TNFα+Actinomycin D and prevented sGAG loss induced by IL-1α. Conclusion Mechanical injury leads to suppression of autophagy, predominantly in the superficial zone where most of the cell death occurs. Pharmacological inhibition of mTORC1, at least in part by enhancement of autophagy prevented cell and matrix damage suggesting a novel approach for chondroprotection.

Exp Clin Endocrinol Diabetes

“…Rat thoracic aorta vascular endothelial cells (ECs) were isolated as described previously [20,21]. The ECs were incubated in Dulbecco's modified Eagle's medium (DMEM; Thermo Fisher Scientific, Inc., Waltham, MA, USA) and supplemented with 10 % FBS, 100 μg/ mL streptomycin and 100 IU/mL penicillin (all of them from Sigma-Aldrich) at 37 °C in a humidified incubator (Thermo Fisher Scientific, Inc.) with a 5 % CO 2 , 95 % air atmosphere.…”

Section: Reagent and Cell Culturementioning

confidence: 99%

Intravenous Injection of miR-34a Inhibitor Alleviates Diabetes Mellitus-Induced Vascular Endothelial Dysfunction by Targeting NOTCH1

Zhao

Wang

et al. 2018