Identification and functional characterization of a putative IDE, C28F5.4 (ceIDE-1), in Caenorhabditis elegans: Implications for Alzheimer's disease

Synergistic effects of hIAPP and Aβ1-42 impaired the olfactory function associated with the decline of adult neurogenesis in SVZ

According to many in the field，the prevalence of Alzheimer's disease (AD) in type II diabetes (T2DM) populations is considerably higher than that in the normal population. Human islet amyloid polypeptide (hIAPP) is considered to be a common risk factor for T2DM and AD. Preliminary observations around T2DM animal model show that the decrease of adult neural stem cells (NSCs) in the subventricular zone (SVZ) is accompanied by olfactory dysfunction. Furthermore, impaired olfactory function could serve as to an early predictor of neurodegeneration，which is associated with cognitive impairment. However, the synergistic effects between hIAPP and amyloid-beta (Aβ) _1-42 in the brain and the neurodegeneration remains to be further clarified. In this study, olfactory capacity, synaptic density, status of NSC in SVZ, and status of newborn neurons in olfactory bulb (OB) were assessed 6 months after stereotactic injection of oligomer Aβ_1-42 into the dens gyrus (DG) of hIAPP-/+ mice or wild-type homogenous mice. Our results set out that Aβ₄₂ and amylin co-localized into OB and raised Aβ₄₂ deposition in hIAPP^-/+ mice compared with wild-type brood mice. In addition, 6 months after injection of Aβ_1-42 in hIAPP^-/+ mice, these mice showed increased olfactory dysfunction, significant loss of synapses, depletion of NSC in SVZ, and impaired cell renewal in OB. Our present study suggested that the synergistic effects between hIAPP and Aβ_1-42 impairs olfactory function and was associated with decreased neurogenesis in adults with SVZ.

Voltammetric lipase activity assay based on dilinolein and a modified carbon paste electrode

In this work, a novel electrochemical assay for characterizing both lipases and lipase inhibitors as well as for the determination of lipase activity is described. It is based on a carbon paste electrode, modified with cobalt(II)phthalocyanine, and multi-walled carbon nanotubes (MWCNTs). As reaction media, a sodium borate buffer was used (0.1 M, pH 9). The measurements were carried out in a batch system using differential pulse voltammetry (DPV) and 1,3-dilinolein as standard substrate. The activity assay showed a linearity for porcine pancreas lipase activity in a range between 20 and 300 U L⁻¹ (per min) with a limit of detection (LOD) of 7 U L⁻¹ and a limit of quantification (LOQ) of 20 U L⁻¹. The kinetic behavior of the lipase reaction was investigated, resulting in a K_M value of 0.29 mM. The applicability of the activity assay could be shown by investigating the activity of lipases from Aspergillus oryzae and Candida rugosa, and the results were confirmed by a reference method. The inhibitory effects were characterized with Orlistat.

Role of GPR40 in pathogenesis and treatment of Alzheimer's disease and type 2 diabetic dementia

G-protein coupled receptor 40 (GPR40) is also known as free fatty acid receptor 1. It is a typical 7 transmembrane receptor and currently the natural receptor of the saturated or unsaturated long-chain fatty acids. It could trigger the intracellular signalling pathway when combined with the free long-chain fatty acids, thereby controlling cells physiological function. In this review, we summarised the relationships and the potential mechanisms between the promising target GPR40, and pathogenesis and treatment of Alzheimer's disease and type 2 diabetic dementia. It may provide a theoretical reference for the development of clinical drug targeting GPR40.

Effect of the electro-acupuncture on senile plaques and its formation in APP+/PS1+ double transgenic mice

Alzheimer's disease (AD) is a progressive neurodegenerative disease and its incidence will increase with age and is aggravating. The senile plaques (SPs) are one of three main pathological features in AD patients, which are formed by amyloid β-protein (Aβ) over-accumulation. β-amyloid precursor protein (APP), β-site APP cleavage (BACE1), and insulin degrading enzyme (IDE) proteins participate in the process of Aβ production and degradation. At present, the pathogenesis of AD is not yet clear and the current treatment methods can only relief the related symptoms of AD. The electro-acupuncture (EA) is a traditional Chinese medicine treatment combined the acupuncture and electrical stimulation and the treatment effect can also be controlled by transform the electrical frequency. Thus, in this experiment, we carried out behavioral test, immunohistochemistry (IHC), and Western Blot (WB) after different period treatments to the model mice by electro-acupuncturing “Baihui” and “Shenshu” acupoints in APP⁺/PS1⁺ double transgenic mice. It was found that the EA therapy can improve the ability of learning, memory and spatial exploration, and reduce the deposition of SPs in brain of AD model mice, and reduce the expressions of APP and BACE1, increase the expression of IDE protein. These results prompt that EA can effectively alleviate the pathological process of AD. We speculate that EA may play a comprehensive role in preventing the development of AD, considering the previous data.

In vitro assessment of selected Korean plants for antioxidant and antiacetylcholinesterase activities

CONTEXT

Antiacetylcholinesterase (AChE) drugs have been a main therapeutic treatment for Alzheimer's disease because increased AChE levels play a key role in reducing neurotransmission.

OBJECTIVES

Extracts from 35 Korean plants were selected and screened for antioxidant and anti-cholinesterase activity to explore new sources derived from Korean natural resources that could be used as AD therapeutic agents.

MATERIALS AND METHODS

The antioxidant effect of extracts from 35 selected Korean plants was determined using two most common free radical scavenging assays using 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis-3-ethylbenzthiazoline-6-sulphonic acid (ABTS). Additionally, the effect of extracts, identified as antioxidants, on acetylcholinesterase inhibition was assessed by an acetylcholinesterase assay kit.

RESULTS

Out of 36 extracts of 35 plants tested, Oenothera biennis L. (9.09 μg/mL), Saururus chinensis (Lour.) Baill. (9.52 μg/mL) and Betula platyphylla var. japonica (9.85 μg/mL) showed strong DPPH scavenging activity. Twelve other extracts also exerted moderate free radical scavenging activities with IC50 values ranging from 10 to 50 μg/mL. Antioxidant capacity detected by ABTS assay was only significant in O. biennis (23.40 μg/mL), while the other extracts were weak or unable to reduce the production of ABTS. Based on the antioxidant activities of these plant extracts, 19 extracts with IC50 values less than 100 μg/mL in DPPH assay were selected for further AChE inhibition assay. Among the extracts tested, the IC50 value for Prunella vulgaris var. lilacina NAKAI (18.83 μg/mL) in AChE inhibitory activity was the lowest, followed by O. biennis (20.09 μg/mL) and Pharbitis nil Chosy (22.79 μg/mL).

CONCLUSIONS

Considering complex multifactorial etiology of AD, the extracts of P. vulgaris var. lilacina (aerial part), O. biennis (seed) and P. nil (seed) may be safe and ideal candidates for future AD modifying therapies.