Amyloid beta (Aβ) precursor protein (APP) is a key protein in the pathogenesis of Alzheimer's disease (AD). Both APP and its paralogue APLP1 (amyloid beta precursor-like protein 1) have multiple functions in cell adhesion and proliferation. Previously it was thought that autophagy is a novel beta-amyloid peptide (Aβ)-generating pathway activated in AD. However, the protein proteolysis of APLP1 is still largely unknown. The present study shows that APLP1 is rapidly degraded in neuronal cells in response to stresses, such as proteasome inhibition. Activation of the endoplasmic reticulum (ER) stress by proteasome inhibitors induces autophagy, causing reduction of mature APLP1/APP. Blocking autophagy or JNK stress kinase rescues the protein expression for both APP and APLP1. Therefore, our results suggest that APP/APLP1 is degraded through autophagy and the APLP1 proteolysis is mainly mediated by autophagy-lysosome pathway.
Amyloid beta-Protein Precursor ; genetics ; metabolism ; Animals ; Autophagy ; Cell Line ; Endoplasmic Reticulum ; metabolism ; JNK Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; metabolism ; Leupeptins ; pharmacology ; Mice ; Neurons ; cytology ; metabolism ; Proteasome Endopeptidase Complex ; metabolism ; Proteasome Inhibitors ; Protein Stability ; Rats

We investigate the role of β-catenin signaling in the response of macrophage to lipopolysaccharide (LPS) using RAW264.7 cells. LPS rapidly stimulated cytosolic β-catenin accumulation. β-catenin-mediated transcription was showed to be required for LPS induced gene expression and cell migration. Mechanically, ERK activation-primed GSK3β inactivation by Akt was demonstrated to mediate the LPS induced β-catenin accumulation. Overall, our findings suggest that suppression of GSK3β by ERK stimulates β-catenin signaling therefore contributes to LPS induced cell migration in macrophage activation.
Animals ; Cell Line ; Cell Movement ; drug effects ; Enzyme Activation ; drug effects ; Extracellular Signal-Regulated MAP Kinases ; metabolism ; Gene Expression Regulation, Enzymologic ; drug effects ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Lipopolysaccharides ; pharmacology ; Macrophages ; cytology ; drug effects ; enzymology ; metabolism ; Matrix Metalloproteinase 9 ; genetics ; Mice ; Proto-Oncogene Proteins c-akt ; metabolism ; Signal Transduction ; drug effects ; Transcription, Genetic ; drug effects ; Wnt Proteins ; metabolism ; beta Catenin ; metabolism

The Wnt/β-catenin and bone morphogenetic proteins (BMPs) pathways play important roles in controlling osteogenesis. Using a cell-based kinase inhibitor screening assay, we identified the compound bisindoylmaleimide I (BIM) as a potent agonist of the cytosolic β-catenin accumulation in preosteoblast cells. Through suppressing glycogen synthase kinase 3β enzyme activities, BIM upregulated β-catenin responsive transcription and extended duration of BMP initiated signal. Functional analysis revealed that BIM promoted osteoblast differentiation and bone formation. The treatment of human mesenchymal stem cells with BIM promoted osteoblastogenesis. Our findings provide a new strategy to regulate mesenchymal stem cell differentiation by integration of the cellular signaling pathways.
Animals ; Bone Morphogenetic Proteins ; metabolism ; Cell Differentiation ; drug effects ; Cell Line, Tumor ; Glycogen Synthase Kinase 3 ; metabolism ; Glycogen Synthase Kinase 3 beta ; Indoles ; chemistry ; pharmacology ; Maleimides ; chemistry ; pharmacology ; Mesenchymal Stem Cells ; cytology ; metabolism ; Mice ; Osteoblasts ; cytology ; drug effects ; metabolism ; RNA Interference ; RNA, Small Interfering ; metabolism ; Signal Transduction ; drug effects ; Wnt Proteins ; metabolism ; beta Catenin ; antagonists & inhibitors ; genetics ; metabolism

Objective:To analyze the body composition of breast cancer patients and the changes with age; to compare the incidence of obesity in breast cancer patients with different diagnostic criteria; To understand the relationship between body mass index (BMI) and body composition; to investigate the incidence of sarcopenia and its relationship with obesity in breast cancer patients.Methods:The bioelectrical impedance technique was used to analyze the body composition of 1 187 female breast cancer patients before surgery.Results:There was a statistically significant difference between different age groups of breast cancer patients with various body composition indicators ( F values were 3.767-32.627, P < 0.01), and the incidence of obesity and sarcopenia was different in different age groups ( χ2 value was 20.819, P < 0.01). The obesity detection rate of different diagnostic methods was different. The obesity rate diagnosed by body fat percentage (PBF) was the highest. 28.14% (334/1 187) of breast cancer patients were diagnosed as "invisible obesity", which refers to normal or low BMI but excessive PBF. BMI was positively correlated with all body composition indicators ( r values were 0.137-0.954, P < 0.01), and moderately correlated with PBF and skeletal muscle mass ( r values were 0.761, 0.534, P < 0.01). The incidence of sarcopenia in breast cancer patients was 8.26% (98/1 187). 8.78% (64/1 187) of the patients with normal BMI were diagnosed as Sarcopenia. Among patients with excess PBF and excess visceral fat area, 6.70% (47/1 187) and 5.98% (15/1 187) were diagnosed with sarcopenia, respectively. Conclusion:The incidence of PBF obesity in breast cancer patients is high, and some patients have sarcopenia, which is not good for prognosis. Bioelectrical impedance technology can accurately assess the body composition of patients, and can find "invisible obesity" and sarcopenia that cannot be diagnosed by BMI, which is worthy of further promotion and application in clinical practice.