ABSTRACT
Purpose: Cerebral ischemia-reperfusion (I/R) is a neurovascular disorder that leads to brain injury. In mice, Fasudil improves nerve injury induced by I/R. However, it is unclear if this is mediated by increased peroxisome proliferator-activated receptor-α (PPARα) expression and reduced oxidative damage. This study aimed to investigate the neuroprotective mechanism of action of Fasudil. Methods: MCAO (Middle cerebral artery occlusion) was performed in male C57BL/6J wild-type and PPARα KO mice between September 2021 to April 2023. Mice were treated with Fasudil and saline; 2,3,5-Triphenyltetrazolium chloride (TTC) staining was performed to analyze cerebral infarction. PPARα and Rho-associated protein kinase (ROCK) expression were detected using Western blot, and the expression of NADPH subunit Nox2 mRNA was detected using real-time polymerase chain reaction. The NADPH oxidase activity level and reactive oxygen species (ROS) content were also investigated. Results: After cerebral ischemia, the volume of cerebral necrosis was reduced in wild-type mice treated with Fasudil. The expression of PPARα was increased, while ROCK was decreased. Nox2 mRNA expression, NADPH oxidase activity, and ROS content decreased. There were no significant changes in cerebral necrosis volumes, NADPH oxidase activity, and ROS content in the PPARα KO mice treated with Fasudil. Conclusions: In mice, the neuroprotective effect of Fasudil depends on the expression of PPARα induced by ROCK-PPARα-NOX axis-mediated reduction in ROS and associated oxidative damage.
Subject(s)
Animals , Mice , Brain Injuries , Reperfusion Injury , Brain Ischemia , Oxidative StressABSTRACT
Abnormal aggregation of Tau in glial cells has been reported in Alzheimer's disease (AD) and other tauopathies; however, the pathological significance of these aggregates remains unsolved to date. In this study, we evaluated whether full-length Tau (Tau441) and its aspartic acid421-truncated Tau variant (Tau421) produce alterations in the normal organization of the cytoskeleton and plasma membrane (PM) when transiently expressed in cultured C6-glial cells. Forty-eight hours post-transfection, abnormal microtubule bundling was observed in the majority of the cells, which expressed either Tau441 or Tau421. Moreover, both variants of Tau produced extensive PM blebbing associated with cortical redistribution of filamentous actin (F-Actin). These effects were reverted when Tau-expressing cells were incubated with drugs that depolymerize F-Actin. In addition, when glial cells showing Tau-induced PM blebbing were incubated with inhibitors of the Rho-associated protein kinase (ROCK) signaling pathway, both formation of abnormal PM blebs and F-Actin remodeling were avoided. All of these effects were initiated upstream by abnormal Tau-induced microtubule bundling, which may release the microtubule-bound guanine nucleotide exchange factor-H1 (GEF-H1) into the cytoplasm in order to activate its major effector RhoA-GTPase. These results may represent a new mechanism of Tau toxicity in which Tau-induced microtubule bundling produces activation of the Rho-GTPase-ROCK pathway that in turn mediates the remodeling of cortical Actin and PM blebbing. In AD and other tauopathies, these Tau-induced abnormalities may occur and contribute to the impairment of glial activity.
Subject(s)
Actins/metabolism , Cell Membrane/metabolism , Neuroglia/metabolism , rho-Associated Kinases/metabolism , rhoA GTP-Binding Protein/metabolism , tau Proteins/metabolism , Actins/drug effects , Animals , Blotting, Western , Cell Line , Cell Membrane/drug effects , Cell Membrane/pathology , Cytoplasm/metabolism , Electrophoresis , Fluorescent Antibody Technique , Green Fluorescent Proteins/genetics , Green Fluorescent Proteins/metabolism , Guanine Nucleotide Exchange Factors/metabolism , In Situ Nick-End Labeling , Microscopy, Confocal , Neuroglia/drug effects , Neuroglia/pathology , Rats , Signal Transduction/drug effects , Transfection , Tubulin/metabolism , tau Proteins/geneticsABSTRACT
Breast cancer is the most common tumor in women and it has high mortality mainly due to the occurrence of tumor metastasis. Both the processes of cell migration and anchorage to the substrate are essential for the development of metastasis. These processes occur by rearrangements of the actin cytoskeleton, regulated by Rho-associated protein kinase 1 (ROCK-1). The degradation of the extracellular matrix, influenced by metalloproteinase 9 (MMP-9) also exerts greater cell invasiveness. The present study evaluated the ROCK-1 and MMP-9 proteins using an immunohistochemical method through the selection of invasive ductal breast carcinoma. The protein expression was correlated to clinicopathological parameters and overall survival of the patients. High expression of the ROCK-1 protein was correlated statistically to the status of lymph nodes (p=0.007) and showed variable expression in different clinical stages of the tumor. MMP-9 showed a strong immunostaining in patients with metastasis that had died, whereas there was no marker in normal breast tissues. In addition, 46.6% of patients classified as poor prognosis showed high expression of ROCK-1 and MMP-9 protein and another 40.0% just showed high expression of MMP-9. Thus, the differential expression of ROCK-1 and MMP-9 proteins suggests their potential use as prognostic markers in breast cancer.