The Potential of Indole/Indolylquinoline Compounds in Tau Misfolding Reduction by Enhancement of HSPB1.

BACKGROUND: Neurofibrillary tangles formed from tau misfolding have long been considered one of the pathological hallmarks of Alzheimer's disease (AD). The misfolding of tau in AD correlates with the clinical progression of AD and inhibition or reversal of tau misfolding may protect the affected neurons. METHODS: We generated 293 and SH-SY5Y cells expressing DsRed-tagged pro-aggregation mutant of repeat domain of tau (ΔK280 tauRD ) to test indole/indolylquinoline derivatives for reducing tau misfolding and neuroprotection. RESULTS: Four of the 10 derivatives tested displayed good misfolding-inhibitory effects on Tet-On 293 cells. Among them, NC009-1 and NC009-7 enhanced heat-shock 27 kDa protein 1 (HSPB1) expression to increase ∆K280 tauRD -DsRed solubility and promoted neurite outgrowth in Tet-On SH-SY5Y cells. Knockdown of HSPB1 resulted in decreased ∆K280 tauRD -DsRed solubility and reduced neurite outgrowth, which were rescued by addition of NC009-1/NC009-7. Treatment with indole/indolylquinoline derivatives also improved neuronal cell viability and neurite outgrowth in mouse hippocampal primary culture under tau cytotoxicity. CONCLUSION: Our results demonstrate how indole/indolylquinoline derivatives are likely to work in tau misfolding reduction, providing insight into the possible working mechanism of indole and indolylquinoline derivatives in AD treatment.

Identifying GSK-3ß kinase inhibitors of Alzheimer's disease: Virtual screening, enzyme, and cell assays.

Glycogen synthase kinase 3ß (GSK-3ß) is widely known as a critical target protein for treating Alzheimer's disease (AD). We utilized virtual screening to search databases for compounds with the potential to be used in drugs targeting GSK-3ß kinase, and kinase as well as cell assays to investigate top-scored, selected compounds. Virtual screening of >1.1 million compounds in the ZINC and in-house databases was conducted using an optimized computational protocol in the docking program GOLD. Of the top-ranked compounds, 16 underwent a luminescent kinase assay and a cell assay using HEK293 cells expressing DsRed-tagged ΔK280 in the repeat domain of tau (tauRD). The compounds VB-003 (a potent GSK-3ß inhibitor) and VB-008 (AM404, an anandamide transport inhibitor), with determined IC50 values of 0.25 and 5.4µM, respectively, were identified as reducing tau aggregation. Both compounds increased expression of phospho-GSK-3ß (Ser9) and reduced endogenous tau phosphorylation at the sites of Ser202, Thr231, and Ser396. In the ∆K280 tauRD-DsRed SH-SY5Y cells, VB-008, but not VB-003, enhanced HSPB1 and GRP78 expression, increased ∆K280 tauRD-DsRed solubility, and promoted neurite outgrowth. Thus VB-008 performed best to the end of the present study. The identified compound VB-008 may guide the identification and synthesis of potential inhibitors analogous to this compound.

The aqueous extract of Glycyrrhiza inflata can upregulate unfolded protein response-mediated chaperones to reduce tau misfolding in cell models of Alzheimer's disease.

BACKGROUND: Alzheimer's disease (AD) and several neurodegenerative disorders known as tauopathies are characterized by misfolding and aggregation of tau protein. Although several studies have suggested the potential of traditional Chinese medicine (TCM) as treatment for neurodegenerative diseases, the role of TCM in treating AD and tauopathies have not been well explored. MATERIALS AND METHODS: Tau protein was coupled to the DsRed fluorophore by fusing a pro-aggregation mutant of repeat domain of tau (ΔK280 tauRD) with DsRed. The ΔK280 tauRD-DsRed fusion gene was then used to generate Tet-On 293 and SH-SY5Y cell clones as platforms to test the efficacy of 39 aqueous extracts of TCM in reducing tau misfolding and in neuroprotection. RESULTS: Seven TCM extracts demonstrated a significant reduction in tau misfolding and reactive oxidative species with low cytotoxicity in the ΔK280 tauRD-DsRed 293 cell model. Glycyrrhiza inflata and Panax ginseng also demonstrated the potential to improve neurite outgrowth in the ΔK280 tauRD-DsRed SH-SY5Y neuronal cell model. G. inflata further rescued the upregulation of ERN2 (pro-apoptotic) and downregulation of unfolded-protein-response-mediated chaperones ERP44, DNAJC3, and SERP1 in ΔK280 tauRD-DsRed 293 cells. CONCLUSION: This in vitro study provides evidence that G. inflata may be a novel therapeutic for AD and tauopathies. Future applications of G. inflata on animal models of AD and tauopathies are warranted to corroborate its effect of reducing misfolding and potential disease modification.

The influence of long-term treadmill exercise on bone mass and articular cartilage in ovariectomized rats.

BACKGROUND: Loss of bone quality and deterioration of articular cartilage are commonly seen after menopause. While exercise may protect against tissue degeneration, a clear link has yet to be established. The aim of the present study is to investigate the influence of long-term treadmill exercise on changes in bone mass and articular cartilage in ovariectomized rats. METHODS: Sixty female Sprague-Dawley rats were randomly assigned to 4 groups: ovariectomized (OVX), ovariectomized plus treadmill exercise (OVX-RUN), treadmill exercise alone (RUN), and control (CON) groups. After 36 weeks, the following variables were compared among the 4 groups. Bone mass was evaluated by trabecular bone volume and bone mineral density (BMD). Articular cartilage in the knee joints was evaluated by histology analysis and a modified Mankin score. RESULTS: Rats in the ovariectomized groups (OVX and OVX-RUN) had significantly lower BMD and bone mass than the non-ovariectomized rats (CON and RUN), indicating that exercise did little to preserve bone mass. However, the sedentary OVX group had a significantly worse modified Mankin score (7.7 +/- 1.4) than the OVX-RUN group (4.8 +/- 1.0), whose scores did not differ significantly from the other 2 non-operated groups. The articular cartilage in the sedentary OVX rats was relatively thinner, hypocellular, and had more clefts than in the other 3 groups. CONCLUSION: This study suggests that long-term exercise protects articular cartilage in OVX rats but does not retard the loss of bone mass seen in after menopause.

SSLP-1, a secreted Ly-6 protein purified from mouse seminal vesicle fluid.

The Ly-6 protein family refers to a group of glycophosphatidyl inositol-anchored membrane proteins with ten conserved cysteines. They are thought to be involved in cellular adhesion and signaling. Recently, a subfamily of secreted Ly-6 proteins has been identified. In the present study, we report a secreted Ly-6 protein, secreted seminal vesicle Ly-6 protein 1 (SSLP-1) purified from mouse seminal vesicles using a series of steps including ion-exchange chromatography on a diethylaminoethyl (DEAE)-Sephacel column, gel filtration on a Sephadex G-75 column, and ion-exchange HPLC on a sulfopropyl column. Further analysis demonstrated it to be a novel, previously unnamed, 17 kDa glycoprotein. N-glycosidase F treatment revealed a core protein with a molecular mass of 8720 Da. By Basic Local Alignment Search Tool Protein analysis, we found that SSLP-1 had ten conserved cysteine residues identical with other secreted Ly-6 proteins. The gene Gm191, which is located on chromosome 9, encodes SSLP-1. By Northern blotting with 21 different mouse tissues, we found that Sslp-1 mRNA was predominantly expressed in the seminal vesicle. Immunohistochemistry revealed SSLP-1 protein in the luminal fluid and mucosal epithelium of the seminal vesicles. The amount of Sslp-1 mRNA and SSLP-1 protein in the seminal vesicle was regulated by testosterone and correlated with the stage of animal maturation. The tissue-specific expression pattern suggests that SSLP-1 may play a physiological role in male mouse reproduction.