Circulatory GSK-3ß: Blood-Based Biomarker and Therapeutic Target for Alzheimer's Disease.

BACKGROUND: Alzheimer's disease (AD) is the progressive brain disorder which degenerates brain cells connection and causes memory loss. Although AD is irreversible, it is not impossible to arrest or slow down the progression of the disease. However, this would only be possible if the disease is diagnosed at an early stage, and early diagnosis requires clear understanding of the pathogenesis at molecular level. Overactivity of GSK-3ß and p53 accounts for tau hyperphosphorylation and the formation of amyloid-ß plaques. OBJECTIVE: Here, we explored GSK-3ß and p53 as blood-based biomarkers for early detection of AD. METHODS: The levels of GSK-3ß, p53, and their phosphorylated states were measured using surface plasmon resonance and verified using western blot in serum from AD, mild cognitive impairment (MCI), and geriatric-control (GC) subjects. The neurotoxic SH-SY5Y cell line was treated with antioxidant Emblica Officinalis (EO) for rescue effect. RESULTS: GSK-3ß, p53, and their phosphorylated states were significantly over expressed (p > 0.001) in AD and MCI compared to GC and can differentiate AD and MCI from GC. The expression level of GSK-3ß and p53 proteins were found to be downregulated in a dose-dependent manner after the treatment with EO in amyloid-b-induced neurotoxic cells. CONCLUSION: These proteins can serve as potential blood markers for the diagnosis of AD and EO can suppress their level. This work has translational value and clinical utility in the future.

Design and in vitro analysis of SIRT2 inhibitor targeting Parkinson's disease.

Inhibition of Sirtuin2 (SIRT2) protein rescues the α-synuclein toxicity in vitro and in vivo models of Parkinson's disease (PD). Thioacetyl group can structurally mimic the acetyl group and restrain the deacetylating p53 reaction by SIRT2. This work evaluated the biological activity of designed pentapeptides inhibitor containing N-thioacetyl-lysine against SIRT2. Pentapeptide by introducing thioacetyl-lysine as an inhibitor of SIRT2 was screened by molecular docking and synthesized by solid phase method. The inhibition of pure recombinant SIRT2 as well as SIRT2 in serum of PD patients by peptide was done by fluorescent activity assay. The inhibition of SIRT2 was assessed in PC12 cell line by measuring acetylated α-tubulin level. The peptide YKK(ε-thioAc)AM and HRK(ε-thioAc)AM were found to be SIRT2 inhibitors by molecular docking. However, YKK(ε-thioAc)AM was more specific towards SIRT2 than SIRT1 (Sirtuin1). It inhibited recombinant SIRT2 by IC50 value of 0.15 µM and KD values 9.92 × 10-8/M. It also inhibited serum SIRT2 of PD. It increased the acetylation of α-tubulin in PC12 neuroblastoma cells which is essential for maintaining the microtubular cell functions of brain. It can be concluded that novel peptide YKK(ε-thioAc)AM may be a platform for therapeutic agent for Parkinson's disease targeting SIRT2.

Neuroprotection by ethanolic extract of Syzygium aromaticum in Alzheimer's disease like pathology via maintaining oxidative balance through SIRT1 pathway.

The oxidative stress plays a key role in Alzheimer's disease (AD) and Sirtuin (SIRT1) is potential mediator of oxidative pathway. This study explored the role of Syzygium aromaticum on SIRT1 and oxidative balance in amyloid beta induced toxicity. Anti-oxidative capacity of Syzygium aromaticum was performed in Aß25-35 induced neurotoxicity in neuronal cells. Superoxide dismutase, Catalase and Glutathione enzyme activity were determined by the treatment of Syzygium aromaticum. Both recombinant and endogenous SIRT1 activity were performed in its presence. The expression of γ-secretase and SIRT1 were evaluated by western blot. Syzygium aromaticum was capable to scavenge ROS and elevate the percentage of anti-oxidant enzymes. It also activated and elevated the level of SIRT1 and downregulated γ-secretase level. These findings show a holistic approach towards the neurodegenerative disease management by Syzygium aromaticum which could lead to the formulation of new drug for AD. This Ayurvedic product can give a healthy aging with no side effects and also be cost effectives. It may meet unmet medical needs of current relevance.

5-LOX in Alzheimer's Disease: Potential Serum Marker and In Vitro Evidences for Rescue of Neurotoxicity by Its Inhibitor YWCS.

The inflammatory process plays a key role in neurodegenerative disorder. The inflammatory molecule, 5-lipooxygenase (5-LOX), protein is involved in the pathologic phenotype of Alzheimer's disease (AD) which includes Aß amyloid deposition and tau hyperphosphorylation. This study determined the level of 5-LOX in serum of AD patients, mild cognitive impairment (MCI) patients, and the normal elderly, and the rescue effect by YWCS, a peptide inhibitor of 5-LOX on neurotoxicity by Aß amyloid25-35 (Aß25-35) in neuroblastoma cells. The concentration of serum 5-LOX was estimated by surface plasmon resonance and western blot. The neuroprotective effect of 5-LOX peptide inhibitor YWCS in Aß25-35-induced neurotoxicity was analyzed by MTT assay and western blotting. We found significant upregulated serum 5-LOX in AD patients and also in MCI patients compared to the normal control group. The peptide inhibitor of 5-LOX, YWCS, prevented the neurotoxic effect of Aß25-35 by reducing the expression of γ-secretase as well as p-Tau181 in SH-SY5Y cells. However, YWCS was nontoxic towards normal HEK cells. The differential expression of serum 5-LOX among the study groups suggests it can be one of potential serum protein marker and a therapeutic regimen for AD and MCI. The negative correlation with neuropsychological parameters, i.e., MoCA and HMSE, increases its importance and makes it useful during the clinical setup which is very needful in developing countries. Peptide YWCS can serve as a new platform as a 5-LOX inhibitor which can prevent neurotoxicity developed in AD.

DS6: anticandidal, antibiofilm peptide against Candida tropicalis and exhibit synergy with commercial drug.

Antifungal peptides have gained interest as therapeutic agents in recent years because of increased multidrug resistance against present antifungal drugs. This study designed, synthesized and characterized antifungal activity of a small peptide analogue, DS6. This peptide was designed using the template from the N-terminal part of the antifungal protein, Aspergillus giganteous. DS6 inhibited Candida tropicalis (ATCC 13803), as well as its clinical isolates. DS6 was found to be a fungicidal, killing the fungus very rapidly. DS6 is also non-toxic to human cells. Synergistic interactions of DS6 with amphotericin B and fluconazole were also evident. DS6 is membrane lytic and exhibits antibiofilm activity against C. tropicalis. In conclusion, DS6 may have utility as an alternative antifungal therapy for C. tropicalis. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.