Methionine sulfoxide reductase A negatively controls microglia-mediated neuroinflammation via inhibiting ROS/MAPKs/NF-κB signaling pathways through a catalytic antioxidant function

Inhibitory effects of three bisbenzylisoquinoline alkaloids on lipopolysaccharide-induced microglial activation

Three bisbenzylisoquinoline alkaloids (liensinine, neferine, and isoliensinine) inhibit lipopolysaccharide-induced microglial activation.

Protein methionine oxidation augments reperfusion injury in acute ischemic stroke

Reperfusion injury can exacerbate tissue damage in ischemic stroke, but little is known about the mechanisms linking ROS to stroke severity. Here, we tested the hypothesis that protein methionine oxidation potentiates NF-κB activation and contributes to cerebral ischemia/reperfusion injury. We found that overexpression of methionine sulfoxide reductase A (MsrA), an antioxidant enzyme that reverses protein methionine oxidation, attenuated ROS-augmented NF-κB activation in endothelial cells, in part, by protecting against the oxidation of methionine residues in the regulatory domain of calcium/calmodulin-dependent protein kinase II (CaMKII). In a murine model, MsrA deficiency resulted in increased NF-κB activation and neutrophil infiltration, larger infarct volumes, and more severe neurological impairment after transient cerebral ischemia/reperfusion injury. This phenotype was prevented by inhibition of NF-κB or CaMKII. MsrA-deficient mice also exhibited enhanced leukocyte rolling and upregulation of E-selectin, an endothelial NF-κB-dependent adhesion molecule known to contribute to neurovascular inflammation in ischemic stroke. Finally, bone marrow transplantation experiments demonstrated that the neuroprotective effect was mediated by MsrA expressed in nonhematopoietic cells. These findings suggest that protein methionine oxidation in nonmyeloid cells is a key mechanism of postischemic oxidative injury mediated by NF-κB activation, leading to neutrophil recruitment and neurovascular inflammation in acute ischemic stroke.

The inhibitory effects of carnosic acid on cervical cancer cells growth by promoting apoptosis via ROS-regulated signaling pathway

Cervical cancer has been the fourth most common cancer killing many women across the world. Carnosic acid (CA), as a phenolic diterpene, has been suggested to against cancer, exerting protective effects associated with inflammatory cytokines. It is aimed to demonstrate the therapeutic role of carnosic acid against cervical cancer and indicate its underlying molecular mechanisms. 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) was performed to assess the possible anti-proliferative effects of carnosic acid. And also, colony formation was used to further estimate carnosic acid's ability in suppressing cervical cancer cells proliferation. Flow cytometry assays were performed here to indicate the alterations of cervical cancer cells cycle and the development of apoptosis. Western blot assays and RT-PCR were also applied to clarify the apoptosis-associated signaling pathways affected by reactive oxygen species (ROS) generation. And immunofluorescence was used to detect ROS-positive cells. In vivo experiments, CaSki xenograft model samples of nude mice were involved to further elucidate the effects of carnosic acid. In our results, we found that carnosic acid exerted anti-tumor ability in vitro supported by up-regulation of apoptosis and ROS production in cervical cancer cells. Also, acceleration of ROS led to the phospharylation of (c-Jun N-terminal kinase (JNK) and its-related signals, as well as activation of Endoplasmic Reticulum (ER) stress, promoting the progression of apoptosis via stimulating Caspase3 expression. The development and growth of xenograft tumors in nude mice were found to be inhibited by the administration of carnosic acid for five weeks. And the suppressed role of carnosic acid in proliferation of cervical cancer cells and apoptosis of nude mice with tumor tissues were observed in our study. Taken together, our data indicated that carnosic acid resulted in apoptosis both in vitro and vivo experiments via promoting ROS and activating JNK signaling pathways in human cervical cancer cells, which supplied a potential therapy for the application of carnosic acid in clinical treatment.

ST09, a Novel Thioester Derivative of Tacrine, Alleviates Cognitive Deficits and Enhances Glucose Metabolism in Vascular Dementia Rats

AIMS

Chemical entities containing mercapto group have been increasingly attractive in the therapy of central nerve system (CNS) diseases. In the recent study, we screened a series of mercapto-tacrine derivatives with synergistic neuropharmacological profiles in vitro.

METHODS

We investigated the effect and mechanism of ST09, a thioester derivative of tacrine containing a potential mercapto group, on the vascular dementia (VaD) model of rat induced by bilateral common carotid arteries occlusion (2-VO).

RESULTS

ST09 and its active metabolite ST10 retained excellent inhibition on acetylcholinesterase (AChE) activity. ST09 significantly attenuated the 2-VO-induced impairment in spatial acquisition performance and inhibited the 2-VO-induced rise of AChE activity. In the VaD model, ST09 attenuated the oxidative stress and decreased the apoptosis in the cortex and hippocampus. Compared with donepezil, ST09 exhibited a better effect on the regeneration of free thiols in 2-VO rats. Interestingly, ST09, not donepezil, greatly improved glucose metabolism in various brain regions of 2-VO rats using functional imaging of (18) F-labeled fluoro-deoxyglucose (FDG) positron emission tomography (PET).

CONCLUSIONS

ST09 may serve as a more promising agent for the therapy of VaD than tacrine owing to the introduction of a potential mercapto group into the parent skeleton.

Deletion of Methionine Sulfoxide Reductase A Does Not Affect Atherothrombosis but Promotes Neointimal Hyperplasia and Extracellular Signal-Regulated Kinase 1/2 Signaling

OBJECTIVE

Emerging evidence suggests that methionine oxidation can directly affect protein function and may be linked to cardiovascular disease. The objective of this study was to define the role of the methionine sulfoxide reductase A (MsrA) in models of vascular disease and identify its signaling pathways.

APPROACH AND RESULTS

MsrA was readily identified in all layers of the vascular wall in human and murine arteries. Deletion of the MsrA gene did not affect atherosclerotic lesion area in apolipoprotein E-deficient mice and had no significant effect on susceptibility to experimental thrombosis after photochemical injury. In contrast, the neointimal area after vascular injury caused by complete ligation of the common carotid artery was significantly greater in MsrA-deficient than in control mice. In aortic vascular smooth muscle cells lacking MsrA, cell proliferation was significantly increased because of accelerated G1/S transition. In parallel, cyclin D1 protein and cdk4/cyclin D1 complex formation and activity were increased in MsrA-deficient vascular smooth muscle cell, leading to enhanced retinoblastoma protein phosphorylation and transcription of E2F. Finally, MsrA-deficient vascular smooth muscle cell exhibited greater activation of extracellular signal-regulated kinase 1/2 that was caused by increased activity of the Ras/Raf/mitogen-activated protein kinase signaling pathway.

CONCLUSIONS

Our findings implicate MsrA as a negative regulator of vascular smooth muscle cell proliferation and neointimal hyperplasia after vascular injury through control of the Ras/Raf/mitogen-activated protein kinase kinase/extracellular signal-regulated kinase 1/2 signaling pathway.