The Gliopeptide ODN, a Ligand for the Benzodiazepine Site of GABAA Receptors, Boosts Functional Recovery after Stroke.

Following stroke, the survival of neurons and their ability to reestablish connections is critical to functional recovery. This is strongly influenced by the balance between neuronal excitation and inhibition. In the acute phase of experimental stroke, lethal hyperexcitability can be attenuated by positive allosteric modulation of GABAA receptors (GABAARs). Conversely, in the late phase, negative allosteric modulation of GABAAR can correct the suboptimal excitability and improves both sensory and motor recovery. Here, we hypothesized that octadecaneuropeptide (ODN), an endogenous allosteric modulator of the GABAAR synthesized by astrocytes, influences the outcome of ischemic brain tissue and subsequent functional recovery. We show that ODN boosts the excitability of cortical neurons, which makes it deleterious in the acute phase of stroke. However, if delivered after day 3, ODN is safe and improves motor recovery over the following month in two different paradigms of experimental stroke in mice. Furthermore, we bring evidence that, during the subacute period after stroke, the repairing cortex can be treated with ODN by means of a single hydrogel deposit into the stroke cavity.SIGNIFICANCE STATEMENT Stroke remains a devastating clinical challenge because there is no efficient therapy to either minimize neuronal death with neuroprotective drugs or to enhance spontaneous recovery with neurorepair drugs. Around the brain damage, the peri-infarct cortex can be viewed as a reservoir of plasticity. However, the potential of wiring new circuits in these areas is restrained by a chronic excess of GABAergic inhibition. Here we show that an astrocyte-derived peptide, can be used as a delayed treatment, to safely correct cortical excitability and facilitate sensorimotor recovery after stroke.

Blockade of Glial Connexin 43 Hemichannels Reduces Food Intake.

The metabolic syndrome, which comprises obesity and diabetes, is a major public health problem and the awareness of energy homeostasis control remains an important worldwide issue. The energy balance is finely regulated by the central nervous system (CNS), notably through neuronal networks, located in the hypothalamus and the dorsal vagal complex (DVC), which integrate nutritional, humoral and nervous information from the periphery. The glial cells' contribution to these processes emerged few year ago. However, its underlying mechanism remains unclear. Glial connexin 43 hemichannels (Cx43 HCs) enable direct exchange with the extracellular space and can regulate neuronal network activity. In the present study, we sought to determine the possible involvement of glial Cx43 HCs in energy balance regulation. We here show that Cx43 is strongly expressed in the hypothalamus and DVC and is associated with glial cells. Remarkably, we observed a close apposition of Cx43 with synaptic elements in both the hypothalamus and DVC. Moreover, the expression of hypothalamic Cx43 mRNA and protein is modulated in response to fasting and diet-induced obesity. Functionally, we found that Cx43 HCs are largely open in the arcuate nucleus (ARC) from acute mice hypothalamic slices under basal condition, and significantly inhibited by TAT-GAP19, a mimetic peptide that specifically blocks Cx43 HCs activity. Moreover, intracerebroventricular (i.c.v.) TAT-GAP19 injection strongly decreased food intake, without further alteration of glycaemia, energy expenditures or locomotor activity. Using the immediate early gene c-Fos expression, we found that i.c.v. TAT-GAP19 injection induced neuronal activation in hypothalamic and brainstem nuclei dedicated to food intake regulation. Altogether, these results suggest a tonic delivery of orexigenic molecules associated with glial Cx43 HCs activity and a possible modulation of this tonus during fasting and obesity.

Galantamine inhibits ß-amyloid-induced cytostatic autophagy in PC12 cells through decreasing ROS production.

OBJECTIVES: Alzheimer's disease (AD) is one of the most prevalent brain diseases among the elderly, majority of which is caused by abnormal deposition of amyloid beta-peptide (Aß). Galantamine, currently the first-line drug in treatment of AD, has been shown to diminish Aß-induced neurotoxicity and exert favourable neuroprotective effects, but the detail mechanisms remain unclear. MATERIALS AND METHODS: Effects of galantamine on Aß-induced cytotoxicity were checked by MTT, clone formation and apoptosis assays. The protein variations and reactive oxygen species (ROS) production were measured by western blotting analysis and dichloro-dihydro-fluorescein diacetate assay, respectively. RESULTS: Galantamine reversed Aß-induced cell growth inhibition and apoptosis in neuron cells PC12. Aß activated the entire autophagy flux and accumulation of autophagosomes, and the inhibition of autophagy decreased the protein level of cleaved-caspase-3 and Aß-induced cytotoxicity. Meanwhile, galantamine suppressed Aß-mediated autophagy flux and accumulation of autophagosomes. Moreover, Aß upregulated ROS accumulation, while ROS scavengers N-acetyl-l-cysteine impaired Aß-mediated autophagy. Further investigation showed that galantamine downregulated NOX4 expression to inhibit Aß-mediated ROS accumulation and autophagy. CONCLUSIONS: Galantamine inhibits Aß-induced cytostatic autophagy through decreasing ROS accumulation, providing new insights into deep understanding of AD progression and molecular basis of galantamine in neuroprotection.

Balancing Effect of Biejiajian Oral Liquid () on ACE-Ang II-AT1R Axis and ACE2-Ang-(1-7)-Mas Axis in Rats with CCl4-Induced Hepatic Fibrosis.

OBJECTIVE: To explore the effect of Biejiajian Oral Liquid (, BOL) on CCl4-induced hepatic fibrosis in rats by detecting the changes in the levels of angiotensin II (Ang II), angiotensin-(1-7) [Ang-(1-7)], angiotensin-converting enzyme (ACE), ACE2, angiotensin II type 1 receptor (AT1R), Mas, etc. METHODS: A total of 180 Wistar rats were randomly divided into two groups by random digital table method: prevention experiment and treatment experiment. Each group was further subdivided into the following 6 subgroups: normal control group, model group, vitamin E [100 mg/(kg·d), VE] group, enalapril [10 mg/(kg·g), Ena] group, high-dosage [20 g/(kg·d)] BOL group, and low-dosage [10 g/(kg·d)] BOL group. The hepatic fibrosis rat model was established by subcutaneous injection of CCl4 for 6 weeks. Prevention experiment and treatment experiment were administered with specific drugs at different times. At the end of treatment experiment, the pathological changes of liver were observed after hematoxylin-eosin staining. The expressions of ingredients in renin-angiotensin-aldosterone system (RAAS) such as AngII, Ang-(1-7), ACE, ACE2, AT1R, Mas, renin, CYP11B2 and angen in liver were detected by enzyme linked immunosorbent assay, immunohistochemistry method or reverse transcription-polymerase chain reaction, respectively. RESULTS: The levels of AngII and Ang-(1-7) at the 6th week increased by 496.10% and 73.64%, respectively, compared with those at the 2nd week in the model group (P<0.01). With prevention or treatment with high-dosage BOL, there was an evident reduction of AngII level but an improvement of Ang-(1-7) level. Specifically, AngII level of high-dosage group decreased by 77.50% in prevention experiment (P=0.000) and by 76.93% in treatment experiment (P=0.002) compared with that in the model group. Ang-(1-7) level increased by 91.69% in prevention experiment (P=0.006) and by 70.77% in the treatment experiment (P=0.010) compared with that in the model group. The expression levels of mRNA of renin, ACE, CYP11B2, angen and AT1R decreased by 58.15%, 99.90%, 99.84%, 99.99% and 99.99% (all P<0.01), respectively. CONCLUSIONS: BOL could help resist liver fibrosis in rats by enhancing the level of each ingredient in ACE2-Ang-(1-7)-Mas axis, while decreasing the level of each ingredient in ACE-AngII-AT1R axis. To some extent, BOL could enhance the regulation of RAAS in rats with CCl4-induced hepatic fibrosis.

Asprosin is a centrally acting orexigenic hormone.

Asprosin is a recently discovered fasting-induced hormone that promotes hepatic glucose production. Here we demonstrate that asprosin in the circulation crosses the blood-brain barrier and directly activates orexigenic AgRP+ neurons via a cAMP-dependent pathway. This signaling results in inhibition of downstream anorexigenic proopiomelanocortin (POMC)-positive neurons in a GABA-dependent manner, which then leads to appetite stimulation and a drive to accumulate adiposity and body weight. In humans, a genetic deficiency in asprosin causes a syndrome characterized by low appetite and extreme leanness; this is phenocopied by mice carrying similar mutations and can be fully rescued by asprosin. Furthermore, we found that obese humans and mice had pathologically elevated concentrations of circulating asprosin, and neutralization of asprosin in the blood with a monoclonal antibody reduced appetite and body weight in obese mice, in addition to improving their glycemic profile. Thus, in addition to performing a glucogenic function, asprosin is a centrally acting orexigenic hormone that is a potential therapeutic target in the treatment of both obesity and diabetes.

Agouti-related peptide neural circuits mediate adaptive behaviors in the starved state.

In the face of starvation, animals will engage in high-risk behaviors that would normally be considered maladaptive. Starving rodents, for example, will forage in areas that are more susceptible to predators and will also modulate aggressive behavior within a territory of limited or depleted nutrients. The neural basis of these adaptive behaviors likely involves circuits that link innate feeding, aggression and fear. Hypothalamic agouti-related peptide (AgRP)-expressing neurons are critically important for driving feeding and project axons to brain regions implicated in aggression and fear. Using circuit-mapping techniques in mice, we define a disynaptic network originating from a subset of AgRP neurons that project to the medial nucleus of the amygdala and then to the principal bed nucleus of the stria terminalis, which suppresses territorial aggression and reduces contextual fear. We propose that AgRP neurons serve as a master switch capable of coordinating behavioral decisions relative to internal state and environmental cues.

Role of αA-crystallin-derived αA66-80 peptide in guinea pig lens crystallin aggregation and insolubilization.

Earlier we reported that low molecular weight (LMW) peptides accumulate in aging human lens tissue and that among the LMW peptides, the chaperone inhibitor peptide αA66-80, derived from α-crystallin protein, is one of the predominant peptides. We showed that in vitro αA66-80 induces protein aggregation. The current study was undertaken to determine whether LMW peptides are also present in guinea pig lens tissue subjected to hyperbaric oxygen (HBO) in vivo. The nuclear opacity induced by HBO in guinea pig lens is the closest animal model for studying age-related cataract formation in humans. A LMW peptide profile by mass spectrometry showed the presence of an increased amount of LMW peptides in HBO-treated guinea pig lenses compared to age-matched controls. Interestingly, the mass spectrometric data also showed that the chaperone inhibitor peptide αA66-80 accumulates in HBO-treated guinea pig lens. Following incubation of synthetic chaperone inhibitor peptide αA66-80 with α-crystallin from guinea pig lens extracts, we observed a decreased ability of α-crystallin to inhibit the amorphous aggregation of the target protein alcohol dehydrogenase and the formation of large light scattering aggregates, similar to those we have observed with human α-crystallin and αA66-80 peptide. Further, time-lapse recordings showed that a preformed complex of α-crystallin and αA66-80 attracted additional crystallin molecules to form even larger aggregates. These results demonstrate that LMW peptide-mediated cataract development in aged human lens and in HBO-induced lens opacity in the guinea pig may have common molecular pathways.

Tenuifolin, a secondary saponin from hydrolysates of polygalasaponins, counteracts the neurotoxicity induced by Aß25-35 peptides in vitro and in vivo.

Alzheimer's disease (AD) is associated with damage to hippocampal neurons and declines in cognitive functions. The accumulation of amyloid peptides is regarded as a crucial event in the initiation of AD. The neurotoxicity induced by Aß25-35 peptides was used to screen for cytoprotective factors in vitro, and the cognitive deficits induced by the injection of Aß25-35 into the hippocampus were used to evaluate effect on learning and memory. Our previous study revealed that hydrolysate of polygalasaponins (HPS) clearly improve the cognitive deficits induced by the injection of Aß25-35 in mice, but the potential active constituent of HPS remains unclear. The purposes of this study were to separate and purify the secondary saponins of HPS, screen for neuroprotective effects of the constituents in vitro, and to evaluate the effect of cognition in vivo. Various chromatographic methods were used to separate and purify the HPS. The neuroprotective effects were examined in Aß25-35-damage-induced PC12 cells. The protective effect of tenuifolin on the cognitive impairments induced by Aß25-35 injection was assessed using the Morris water maze and step-through passive avoidance tests. Tenuifolin and fallaxsaponin A were isolated from the HPS. Tenuifolin possessed neuroprotective effects against Aß25-35-induced apoptosis in PC12 cells and significantly improved the cognitive deficits induced by the intrahippocampal injection of Aß25-35 in mice. Thus, tenuifolin is one of the active constituents of HPS against the neurotoxicity induced by Aß25-35 peptides in vitro and in vivo.

Riluzole prevents soluble Aß1-42 oligomers-induced perturbation of spontaneous discharge in the hippocampal CA1 region of rats.

Abnormal accumulation of soluble amyloid beta (Aß) is believed to cause malfunction of neurons in Alzheimer's disease (AD). The hippocampus is one of the earliest affected brain regions in AD. However, little effort has been made to investigate the effects of soluble Aß1-42 oligomers on discharge properties of hippocampal neurons in vivo. This study was designed to examine the effects of soluble Aß1-42 oligomers on the discharge properties of hippocampal CA1 neurons using extracellular single-unit recordings in vivo. The protective effects of riluzole (RLZ) were also investigated for the prevention of soluble oligomers of Aß1-42-induced alterations in the spontaneous discharge of hippocampal neurons. The results showed that (1) the mean frequency of spontaneous discharge was increased by the local application of 100 µM Aß1-42 oligomers; (2) Aß1-42 oligomers also induced alterations of the neuronal firing patterns in the hippocampal CA1 region; and (3) pretreatment with 20 µM RLZ effectively inhibited the Aß1-42-induced enhancement of spontaneous discharge and alterations of neuronal firing patterns in CA1 neurons. Our study suggested that Aß1-42 oligomers induced hyperactivity and perturbed the firing patterns in hippocampal neurons. RLZ may provide neuroprotective effects on the Aß1-42-induced perturbation of neuronal activities in the hippocampal region of rats.

[Effective Components of three kinds of shen-supplementing Chinese medicine on self-renewal and neuron-like differentiation of NSCs in AD mouse embryos: an experimental research].

OBJECTIVE: To observe the regulatory effects of psoralen, oleanolic acid, and stilbene glucoside, three active components of psoralea fruit, glossy privet fruit and tuber fleeceflower root respectively, on Aß25-35induced self-renewal and neuron-like differentiation of neural stem cells (NSCs). METHODS: Embryonic NSCs werein vitro isolated and cultured from Kunming mice of 14-day pregnancy, and randomly divided into the control group, the Aß25-35 group, the Aß25-35 +psoralen group, the Aß25-35 +oleanolic acid group, and the Aß25-35 + stilbene glucoside group. The intervention concentration of Aß25-35 was 25 µmol/L, and the intervention concentration of three active components of Chinese medicine was 10(-7)mol/L. The effect of three active components of Chinese medicine on the proliferation of NSCs was observed by counting method. The protein expression of Tubulin was observed by Western blot and immunofluorescence. The ratio of Tubulin+/DAPI was caculated. Results Compared with the control group, the sperical morphology of NSCs was destroyed in the Aß25-35 group, the counting of NSCs, the expression of Tubulin protein, and the ratio of Tubulin /DAPI all decreased (P <0.01, P <0.05). Compared with the Aß25-35 group, the counting of NSCs, the expression of Tubulin protein, and the ratio of Tubulin + /DAPI all increased in the three Chinese medicine treated groups (P <0. 01, P <0. 05). CONCLUSIONS: 25 µmol/L Aß25-35 could inhibit self-renewal and neuron-like differentiating of NSCs. But psoralen, oleanolic acid, and stilbene glucoside could promote self-renewal of NSCs and neuron-like differentiation.

ß-Amyloid1-42, HIV-1Ba-L (clade B) infection and drugs of abuse induced degeneration in human neuronal cells and protective effects of ashwagandha (Withania somnifera) and its constituent Withanolide A.

Alzheimer's disease (AD) is characterized by progressive dysfunction of memory and higher cognitive functions with abnormal accumulation of extracellular amyloid plaques and intracellular neurofibrillary tangles throughout cortical and limbic brain regions. Withania somnifera (WS) also known as 'ashwagandha' (ASH) is used widely in Ayurvedic medicine as a nerve tonic and memory enhancer. However, there is paucity of data on potential neuroprotective effects of ASH against ß-Amyloid (1-42) (Aß) induced neuropathogenesis. In the present study, we have tested the neuroprotective effects of Methanol: Chloroform (3:1) extract of ASH and its constituent Withanolide A (WA) against Aß induced toxicity, HIV-1(Ba-L) (clade B) infection and the effects of drugs of abuse using a human neuronal SK-N-MC cell line. Aß when tested individually, induced cytotoxic effects in SK-N-MC cells as shown by increased trypan blue stained cells. However, when ASH was added to Aß treated cells the toxic effects were neutralized. This observation was supported by cellular localization of Aß, MTT formazan exocytosis, and the levels of acetylcholinesterase activity, confirming the chemopreventive or protective effects of ASH against Aß induced toxicity. Further, the levels of MAP2 were significantly increased in cells infected with HIV-1(Ba-L) (clade B) as well as in cells treated with Cocaine (COC) and Methamphetamine (METH) compared with control cells. In ASH treated cells the MAP2 levels were significantly less compared to controls. Similar results were observed in combination experiments. Also, WA, a purified constituent of ASH, showed same pattern using MTT assay as a parameter. These results suggests that neuroprotective properties of ASH observed in the present study may provide some explanation for the ethnopharmacological uses of ASH in traditional medicine for cognitive and other HIV associated neurodegenerative disorders and further ASH could be a potential novel drug to reduce the brain amyloid burden and/or improve the HIV-1 associated neurocognitive impairments.

PINP as a biological response marker during teriparatide treatment for osteoporosis.

Postmenopausal women with severe osteoporosis may require treatment with the bone anabolic drug teriparatide. While changes in bone mineral density (BMD) are one measure of response, BMD changes often require a minimum of one year to observe measureable changes. Biochemical markers of bone turnover change within 1 to 3 months of initiating osteoporosis therapy. Monitoring with a marker such as procollagen type I N propeptide (PINP), an osteoblast-derived protein, during teriparatide treatment may provide clinically useful information for managing patients with osteoporosis. Clinical trials have shown consistent increases in PINP within 3 months of initiating teriparatide, increases that are significantly greater than placebo and significantly different from baseline. Increases in PINP concentrations during teriparatide treatment correlate well with increases in skeletal activity assessed by radioisotope bone scans and quantitative bone histomorphometry parameters. Individuals treated with teriparatide in clinical trials usually experienced an increase in PINP > 10 mcg/L from baseline, while those given placebo usually did not. In the clinical setting, patients experiencing a significant increase in PINP > 10 mcg/L after initiating teriparatide therapy may receive an earlier confirmation of anabolic effect, while those who do not may be assessed for adherence, proper injection technique, or undetected secondary conditions that might mitigate an anabolic response. PINP monitoring may provide information supplemental to BMD monitoring and be a useful aid in managing patients receiving anabolic osteoporosis treatment in the same way that biochemical markers of bone resorption are useful in monitoring antiresorptive therapy. This review examines PINP as a biological response marker during teriparatide treatment for osteoporosis.

Olmesartan potentiates the anti-angiogenic effect of sorafenib in mice bearing Ehrlich's ascites carcinoma: role of angiotensin (1-7).

Local renin-angiotensin systems exist in various malignant tumor tissues; this suggests that the main effector peptide, angiotensin II, could act as a key factor in tumor growth. The underlying mechanisms for the anti-angiogenic effect of angiotensin II type 1 receptor blockers need to be further evaluated. The present study was carried out to investigate the anti-angiogenic effect of olmesartan alone or in combination with sorafenib, an angiotensin (1-7) agonist or an angiotensin (1-7) antagonist in Ehrlich's ascites carcinoma-bearing mice. The tumor was induced by intradermal injection of Ehrlich's ascites carcinoma cells into mice. Tumor discs were used to evaluate the microvessel density; the serum levels of vascular endothelial growth factor (VEGF) and serum insulin-like growth factor I (IGF-I); and their intratumoral receptors, VEGF receptor-2 and IGF-I receptor, respectively. All parameters were determined following the treatment course, which lasted for 21 days post-inoculation. Monotherapy with olmesartan and its combination with sorafenib resulted in a significant reduction in microvessel density and serum levels of VEGF and IGF-I, as well as their intratumoral receptors. In addition, the combination of olmesartan (30 mg/kg) with an angiotensin (1-7) agonist reduced the microvessel density, IGF-I serum levels and the levels of its intratumoral receptor. In conclusion, olmesartan reduced the levels of the angiogenesis markers IGF-I and VEGF and down-regulated the intratumoral expression of their receptors in a dose-dependent manner, and these effects were dependent on the angiotensin (1-7) receptor. These results suggest that olmesartan is a promising adjuvant to sorafenib in the treatment of cancer.

Cognitive-enhancing and antioxidant activities of inhaled coriander volatile oil in amyloid ß(1-42) rat model of Alzheimer's disease.

Coriandrum sativum L., commonly known as coriander and belonging to the Apiaceae family is cultivated throughout the world for its nutritional value. In traditional medicine, coriander is recommended for the relief of pain, anxiety, flatulence, loss of appetite and convulsions. In the present study, the effects of inhaled coriander volatile oil (1% and 3%, daily, for 21days) extracted from C. sativum var. microcarpum on spatial memory performance were assessed in an Aß(1-42) rat model of Alzheimer's disease. The Aß(1-42)-treated rats exhibited the following: decrease of spontaneous alternations percentage within Y-maze task and increase of working memory errors, reference memory errors and time taken to consume all five baits within radial arm maze task. Exposure to coriander volatile oil significantly improved these parameters, suggesting positive effects on spatial memory formation. Assessments of oxidative stress markers in the hippocampal tissue of Aß(1-42)-treated rats showed a significant increase of superoxide dismutase (SOD), lactate dehydrogenase (LDH) and a decrease of glutathione peroxidase (GPX) specific activities along with an elevation of malondialdehyde (MDA) level. Coriander volatile oil significantly decreased SOD and LDH specific activities, increased GPX specific activity and attenuated the increased MDA level. Also, DNA cleavage patterns were absent in the coriander rats, thus suggesting antiapoptotic activity of the volatile oil. Therefore, our results suggest that exposure to coriander volatile oil ameliorates Aß(1-42)-induced spatial memory impairment by attenuation of the oxidative stress in the rat hippocampus.

CREB regulates the expression of neuronal glucose transporter 3: a possible mechanism related to impaired brain glucose uptake in Alzheimer's disease.

Impaired brain glucose uptake and metabolism precede the appearance of clinical symptoms in Alzheimer disease (AD). Neuronal glucose transporter 3 (GLUT3) is decreased in AD brain and correlates with tau pathology. However, what leads to the decreased GLUT3 is yet unknown. In this study, we found that the promoter of human GLUT3 contains three potential cAMP response element (CRE)-like elements, CRE1, CRE2 and CRE3. Overexpression of CRE-binding protein (CREB) or activation of cAMP-dependent protein kinase significantly increased GLUT3 expression. CREB bound to the CREs and promoted luciferase expression driven by human GLUT3-promoter. Among the CREs, CRE2 and CRE3 were required for the promotion of GLUT3 expression. Full-length CREB was decreased and truncation of CREB was increased in AD brain. This truncation was correlated with calpain I activation in human brain. Further study demonstrated that calpain I proteolysed CREB at Gln28-Ala29 and generated a 41-kDa truncated CREB, which had less activity to promote GLUT3 expression. Importantly, human brain GLUT3 was correlated with full-length CREB positively and with activation of calpain I negatively. These findings suggest that overactivation of calpain I caused by calcium overload proteolyses CREB, resulting in a reduction of GLUT3 expression and consequently impairing glucose uptake and metabolism in AD brain.

Photobiomodulation by low-power laser irradiation attenuates Aß-induced cell apoptosis through the Akt/GSK3ß/ß-catenin pathway.

Apoptosis induced by amyloid ß peptide (Aß) is thought to associate with the pathogenesis of Alzheimer disease (AD). Accumulating evidence shows that low-power laser irradiation (LPLI) is capable of reducing Aß-induced apoptosis. However, the underlying mechanisms remain unclear. In this study, we report a novel molecular mechanism by which LPLI attenuates Aß(25-35)-induced apoptosis through the Akt/GSK3ß/ß-catenin pathway. We found that Akt activated by LPLI interacted with GSK3ß and phosphorylated it on Ser9 in the presence of Aß(25-35), which resulted in the inhibition of GSK3ß. Furthermore, LPLI increased the nuclear translocation of ß-catenin and enhanced its T cell factor/lymphocyte enhancer factor-dependent transcriptional activity via the Akt/GSK3ß pathway to promote cell survival upon treatment with Aß(25-35.) Our data demonstrate that LPLI has a prosurvival effect on Aß-induced apoptosis and may be an effective therapeutic strategy in treating AD by targeting GSK3ß.

Aß(1-42) aggregates into non-toxic amyloid assemblies in the presence of the natural polyphenol oleuropein aglycon.

Amyloid aggregation starts with the initial misfolding of peptide/protein precursors, with subsequent structural rearrangement into oligomers and protofibrils; the latter eventually organize into fibrils with shared basic structural features, found deposited in amyloid diseases. Mounting evidence indicates early oligomers as the most toxic amyloid species; accordingly, the search of inhibitors of their growth is considered a promising target to prevent amyloid toxicity. We recently showed that oleuropein aglycon, a polyphenol abundant in the extra virgin olive oil, interferes with the aggregation of amylin (involved in type-2 diabetes), eliminating its cytotoxicity. Here we report that oleuropein aglycon also hinders amyloid aggregation of Aß(1-42) and its cytotoxicity, suggesting a general effect of such polyphenol. In particular, by using a wide panel of different spectroscopic, immunologic, cell viability and imaging techniques we provide a more detailed description of Aß(1-42) structural modifications arising in the presence of the inhibitor and the resulting cytotoxicity. We here report that the polyphenol eliminates the appearance of early toxic oligomers favouring the formation of stable harmless protofibrils, structurally different from the typical Aß(1-42) fibrils. We also show that oleuropein aglycon is maximally effective when is present at the beginning of the aggregation process; furthermore, when added to preformed fibrils, it does not induce the release of toxic oligomers but, rather, neutralizes any residual toxicity possibly arising from the residual presence of traces of soluble oligomers and other toxic aggregates. The possible use of this polyphenol as anti-aggregation molecule is discussed in the light of these data.

HCV peptide (C5A), an amphipathic α-helical peptide of hepatitis virus C, is an activator of N-formyl peptide receptor in human phagocytes.

The hepatitis C virus (HCV) nonstructural 5A, a phosphorylated zinc metalloprotein, is an essential component of the HCV replication complex. An amphipathic α-helical peptide (HCV peptide [C5A]) derived from nonstructural 5A membrane anchor domain possesses potent anti-HCV and anti-HIV activity in vitro. In this study, we aimed to investigate the potential of HCV peptide (C5A) to regulate host immune responses. The capacity of HCV peptide (C5A) in vitro to induce migration and calcium mobilization of human phagocytes and chemoattractant receptor-transfected cells was investigated. The recruitment of phagocytes in vivo induced by HCV peptide (C5A) and its adjuvant activity were examined. The results revealed that HCV peptide (C5A) was a chemoattractant and activator of human phagocytic leukocytes by using a G-protein coupled receptor, namely formyl peptide receptor. In mice, HCV peptide (C5A) induced massive phagocyte infiltration after injection in the air pouch or the s.c. region. HCV peptide (C5A) also acted as an immune adjuvant by enhancing specific T cell responses to Ag challenge in mice. Our results suggest that HCV peptide (C5A) derived from HCV regulates innate and adaptive immunity in the host by activating the formyl peptide receptor.

The neuroprotective effects of tanshinone IIA on ß-amyloid-induced toxicity in rat cortical neurons.

Oxidative stress caused by amyloid ß-peptide (Aß) may play an important role in the pathogenesis of Alzheimer disease (AD). Aß is known to be directly responsible for the production of reactive oxygen species (ROS) and induction of apoptosis. Tanshinone IIA (Tan IIA) is extracted from a traditional herbal medicine Salvia miltiorrhiza BUNGE, which has been shown to protect against oxidative stress and cell death. In this study, we investigated the neuroprotective effect of Tan IIA against Aß25₋35-induced cell death in cultured cortical neurons. Exposure of cortical neurons to 30µM Aß25₋35 caused a significant viability loss, cell apoptosis and decreased activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) as well as increased levels of malondialdehyde (MDA) production. In parallel, Aß25₋35 significant increased the intracellular ROS elevation and decreased mitochondrial membrane potential (MMP). However, pretreatment of the cells with Tan IIA prior to Aß25₋35 exposure suppressed these Aß25₋35-induced cellular events noticeably. In addition, Tan IIA reduced the Aß25₋35-induced increase of caspase-3 activity, and reduced cytochrome c translocation into the cytosol from mitochondria. Furthermore, Tan IIA also ameliorated the Aß25₋35-induced Bcl-2/Bax ratio reduction in cortical neurons. Taken together, these data indicate that Tan IIA protected cultured cortical neurons against Aß25₋35-induced neurotoxicity through its antioxidative potential. Our results strongly suggest that Tan IIA may be effective in treating AD associated with oxidative stress.

Comparable attenuation of Abeta(25-35)-induced neurotoxicity by quercitrin and 17beta-estradiol in cultured rat hippocampal neurons.

In the present work, potential protective effects of quercitrin (a phytoestrogen) on Abeta-induced neurotoxicity in cultured rat hippocampal neurons were investigated in comparison with 17beta-estradiol. Cell viability, oxidative status, and antioxidative potentials were used as comparative parameters. Co-exposure of cultured neurons to Abeta(25-35) with either quercitrin or 17beta-estradiol (50-100 microM) for 72 h attenuated Abeta(25-35)-induced neurotoxicity and lipid peroxidation, but not Abeta(25-35)-induced ROS accumulation. However, only 17beta-estradiol counteracted a reduction in glutathione content and only quercitrin counteracted a reduction in glutathione peroxidase activity. Both compounds displayed no effects on superoxide dismutase activity. A specific estrogen receptor antagonist, ICI 182780, did not abolish neuroprotective effects of quercitrin and 17beta-estradiol. These findings suggested that quercitrin and 17beta-estradiol attenuated Abeta(25-35)-induced neurotoxicity in a comparable manner. Underlying neuroprotective mechanisms of both compounds were probably not related to estrogen receptor-mediated genomic mechanisms but might involve with their antioxidant and free radical scavenging properties.