ABSTRACT
Parkinson's disease (PD) is the most common neurodegenerative movement disease. It is featured by abnormal alpha-synuclein (α-syn) aggregation in dopaminergic neurons in the substantia nigra. Macroautophagy (autophagy) is an evolutionarily conserved cellular process for degradation of cellular contents, including protein aggregates, to maintain cellular homeostasis. Corynoxine B (Cory B), a natural alkaloid isolated from Uncaria rhynchophylla (Miq.) Jacks., has been reported to promote the clearance of α-syn in cell models by inducing autophagy. However, the molecular mechanism by which Cory B induces autophagy is not known, and the α-syn-lowering activity of Cory B has not been verified in animal models. Here, we report that Cory B enhanced the activity of Beclin 1/VPS34 complex and increased autophagy by promoting the interaction between Beclin 1 and HMGB1/2. Depletion of HMGB1/2 impaired Cory B-induced autophagy. We showed for the first time that, similar to HMGB1, HMGB2 is also required for autophagy and depletion of HMGB2 decreased autophagy levels and phosphatidylinositol 3-kinase III activity both under basal and stimulated conditions. By applying cellular thermal shift assay, surface plasmon resonance, and molecular docking, we confirmed that Cory B directly binds to HMGB1/2 near the C106 site. Furthermore, in vivo studies with a wild-type α-syn transgenic drosophila model of PD and an A53T α-syn transgenic mouse model of PD, Cory B enhanced autophagy, promoted α-syn clearance and improved behavioral abnormalities. Taken together, the results of this study reveal that Cory B enhances phosphatidylinositol 3-kinase III activity/autophagy by binding to HMGB1/2 and that this enhancement is neuroprotective against PD.
ABSTRACT
The mammalian target of rapamycin (mTOR) pathway is abnormally activated in lung cancer. However, the anti-lung cancer effect of mTOR inhibitors as monotherapy is modest. Here, we identified that ginsenoside Rh2, an active component of Panax ginseng C. A. Mey., enhanced the anti-cancer effect of the mTOR inhibitor everolimus both in vitro and in vivo. Moreover, ginsenoside Rh2 alleviated the hepatic fat accumulation caused by everolimus in xenograft nude mice models. The combination of everolimus and ginsenoside Rh2 (labeled Eve-Rh2) induced caspase-independent cell death and cytoplasmic vacuolation in lung cancer cells, indicating that Eve-Rh2 prevented tumor progression by triggering paraptosis. Eve-Rh2 up-regulated the expression of c-MYC in cancer cells as well as tumor tissues. The increased c-MYC mediated the accumulation of tribbles homolog 3 (TRIB3)/P62+ aggresomes and consequently triggered paraptosis, bypassing the classical c-MYC/MAX pathway. Our study offers a potential effective and safe strategy for the treatment of lung cancer. Moreover, we have identified a new mechanism of TRIB3/P62+ aggresomes-triggered paraptosis and revealed a unique function of c-MYC.
ABSTRACT
As a cellular bulk degradation and survival mechanism, autophagy is implicated in diverse biological processes. Genome-wide association studies have revealed the link between autophagy gene polymorphisms and susceptibility of autoimmune diseases including systemic lupus erythematosus (SLE) and inflammatory bowel disease (IBD), indicating that autophagy dysregulation may be involved in the development of autoimmune diseases. A series of autophagy modulators have displayed protective effects on autoimmune disease models, highlighting the emerging role of autophagy modulators in treating autoimmune diseases. This review explores the roles of autophagy in the autoimmune diseases, with emphasis on four major autoimmune diseases [SLE, rheumatoid arthritis (RA), IBD, and experimental autoimmune encephalomyelitis (EAE)]. More importantly, the therapeutic potentials of small molecular autophagy modulators (including autophagy inducers and inhibitors) on autoimmune diseases are comprehensively analyzed.
ABSTRACT
Objective To investigate the neuroimaging features in mitochondrial encephalomyopatbies with lactic acidosis and stroke-like episodes(MELAS).Methods Twenty-two clinically diagnosed patients who came from department of neurology,Huashan hospital in October 2003 to July 2006 were analyzed for CT,MRI,MRI contrast,MRA and MRS.Results In all 22 patients,the neuroimaging results of 21 were positive.There were 9 patients lying in hemisphere,12 in both cerebral hemispheres,including occipital,parietal,temporal and frontal lobe.The abnormal areas showed low signal intensity on T_1-weighted MRI,high signal intensity on T_2-weighted MRI and fluid attenuated inversion recovery(FLAIR)images.The lesions of 12/16 patients on MR contrasted images were enhanced.The lesions of one patient showed malacoma-like changes,one showed Fahr syndrome' s change and another showed high signal intensity on MR contrasted images.Conclusion Although the neuroimaging features of MELAS are complicated,the specific ones could help to make the diagnosis.
ABSTRACT
Objective To investigate the role of ?7nAChR in the pathogenesis of Alzheimer's disease(AD)through exploring the relationship between ?7nAChR and A?_(1-42) in AD brains.Methods The accumulation of ?7nAChR and the possible relationship between ?7nAChR and A?_(1-42) were observed in 3 clinically and pathologically confirmed AD brains by immunohistochemistry. 3 normal brains were set as controls.Results Respective staining of anti-?7nAChR and anti-A?_(1-42) showed that the abnormal accumulation of ?7nAChR existed in AD brains. The main location was at hippocampus and temporal cortex which was just in accordance with senile plaque consisted mainly of A?_(1-42). The major part of ?7nAChR was located extra-cellular and within senile plaque from the view of morphology. No accumulation of ?7nAChR existed in normal brains. Co-staining of anti-?7nAChR and anti-A?_(1-42) further showed that ?7nAChR and A?_(1-42) could accumulate together in senile plaque of AD brain. The average rate of positive co-staining in hippocampus, temporal lobe and frontal lobe is 57.8%, 51.0% and 21.8% respectively. The accumulation of ?7nAChR in hippocampus and temporal lobe seems much than that in the frontal lobe. Conclusion ?7nAChR may combine with A?_(1-42) in AD brains. It is suggested that the combination should destroy the ?7nAChR receptor, block the receptor or mediate the injury of cholinergic neurons with the result of recognition and memory impairment and that ?7nAChR might play an important role in the pathogenesis of Alzheimer's disease.