Pre-procambial cells are niches for pluripotent and totipotent stem-like cells for organogenesis and somatic embryogenesis in the peach palm: a histological study

The direct induction of adventitious buds and somatic embryos from explants is a morphogenetic process that is under the influence of exogenous plant growth regulators and its interactions with endogenous phytohormones. We performed an in vitro histological analysis in peach palm (Bactris gasipaes Kunth) shoot apexes and determined that the positioning of competent cells and their interaction with neighboring cells, under the influence of combinations of exogenously applied growth regulators (NAA/BAP and NAA/TDZ), allows the pre-procambial cells (PPCs) to act in different morphogenic pathways to establish niche competent cells. It is likely that there has been a habituation phenomenon during the regeneration and development of the microplants. This includes promoting the tillering of primary or secondary buds due to culturing in the absence of NAA/BAP or NAA/TDZ after a period in the presence of these growth regulators. Histological analyses determined that the adventitious roots were derived from the dedifferentiation of the parenchymal cells located in the basal region of the adventitious buds, with the establishment of rooting pole, due to an auxin gradient. Furthermore, histological and histochemical analyses allowed us to characterize how the PPCs provide niches for multipotent, pluripotent and totipotent stem-like cells for vascular differentiation, organogenesis and somatic embryogenesis in the peach palm. The histological and histochemical analyses also allowed us to detect the unicellular or multicellular origin of somatic embryogenesis. Therefore, our results indicate that the use of growth regulators in microplants can lead to habituation and to different morphogenic pathways leading to potential niche establishment, depending on the positioning of the competent cells and their interaction with neighboring cells. Key message Our results indicate that the use of growth regulators in microplants can lead to habituation and to different morphogenic pathways leading to potential niche establishment, depending on the positioning of the competent cells and their interaction with neighboring cells.

Leishmanicidal activity in vitro of Musa paradisiaca L. and Spondias mombin L. fractions

Visceral leishmaniasis (VL) is a zoonotic disease characterized by infection of mononuclear phagocytes by Leishmania chagasi. The primary vector is Lutzomyia longipalpis and the dog is the main domestic reservoir. The control and current treatment of dogs using synthetic drugs have not shown effectiveness in reducing the incidence of disease in man. In attempt to find new compounds with leishmanicidal action, plant secondary metabolites have been studied in search of treatments of VL. This study aimed to evaluate the leishmanicidal activity of Musa paradisiaca (banana tree) and Spondias mombin (cajazeira) chemical constituents on promastigotes and amastigotes of L. chagasi. Phytochemical analysis by column chromatography was performed on ethanol extracts of two plants and fractions were isolated. Thin layer chromatography was used to compare the fractions and for isolation the substances to be used in vitro tests. The in vitro tests on promastigotes of L chagasi used the MTT colorimetric method and the method of ELISA in situ was used against amastigotes besides the cytotoxicity in RAW 264.7 cells. Of the eight fractions tested, Sm1 and Sm2 from S. mombin had no action against promastigotes, but had good activity against amastigotes. The fractions Mp1 e Mp4 of M. paradisiaca were very cytotoxic to RAW 264.7 cells. The best result was obtained with the fraction Sm3 from S. mombin with IC50 of 11.26 mu g/ml against promastigotes and amastigotes of 0.27 mu g/ml. The fraction Sm3 characterized as tannic acid showed the best results against both forms of Leishmania being a good candidate for evaluation in in vivo tests. (C) 2012 Published by Elsevier B.V.

Immune Regulatory Properties of Allogeneic Adipose-Derived Mesenchymal Stem Cells in the Treatment of Experimental Autoimmune Diabetes

Adipose-derived mesenchymal stem cells (ADMSCs) display immunosuppressive properties, suggesting a promising therapeutic application in several autoimmune diseases, but their role in type 1 diabetes (T1D) remains largely unexplored. The aim of this study was to investigate the immune regulatory properties of allogeneic ADMSC therapy in T cell-mediated autoimmune diabetes in NOD mice. ADMSC treatment reversed the hyperglycemia of early-onset diabetes in 78% of diabetic NOD mice, and this effect was associated with higher serum insulin, amylin, and glucagon-like peptide 1 levels compared with untreated controls. This improved outcome was associated with downregulation of the CD4(+) Th1-biased immune response and expansion of regulatory T cells (Tregs) in the pancreatic lymph nodes. Within the pancreas, inflammatory cell infiltration and interferon-gamma levels were reduced, while insulin, pancreatic duodenal homeobox-1, and active transforming growth factor-beta 1 expression were increased. In vitro, ADMSCs induced the expansion/proliferation of Tregs in a cell contact-dependent manner mediated by programmed death ligand 1. In summary, ADMSC therapy efficiently ameliorates autoimmune diabetes pathogenesis in diabetic NOD mice by attenuating the Th1 immune response concomitant with the expansion/proliferation of Tregs, thereby contributing to the maintenance of functional beta-cells. Thus, this study may provide a new perspective for the development of ADMSC-based cellular therapies for T1D. Diabetes 61:2534-2545, 2012

Single-cell expression analysis of BMP15 and GDF9 in mature oocytes and BMPR2 in cumulus cells of women with polycystic ovary syndrome undergoing controlled ovarian hyperstimulation

To detect expression of bone morphogenetic protein 15 (BMP15) and growth differentiation factor 9 (GDF9) in oocytes, and their receptor type 2 receptor for BMPs (BMPR2) in cumulus cells in women with polycystic ovary syndrome (PCOS) undergoing in vitro fertilization (IVF), and determine if BMPR2, BMP15, and GDF9 expression correlate with hyperandrogenism in FF of PCOS patients. Prospective case-control study. Eighteen MII-oocytes and their respective cumulus cells were obtained from 18 patients with PCOS, and 48 MII-oocytes and cumulus cells (CCs) from 35 controls, both subjected to controlled ovarian hyperstimulation (COH), and follicular fluid (FF) was collected from small (10-14 mm) and large (> 18 mm) follicles. RNeasy Micro Kit (Qiagen(A (R))) was used for RNA extraction and gene expression was quantified in each oocyte individually and in microdissected cumulus cells from cumulus-oocyte complexes retrieved from preovulatory follicles using qRT-PCR. Chemiluminescence and RIA assays were used for hormone assays. BMP15 and GDF9 expression per oocyte was higher among women with PCOS than the control group. A positive correlation was found between BMPR2 transcripts and hyperandrogenism in FF of PCOS patients. Progesterone values in FF were lower in the PCOS group. We inferred that BMP15 and GDF9 transcript levels increase in mature PCOS oocytes after COH, and might inhibit the progesterone secretion by follicular cells in PCOS follicles, preventing premature luteinization in cumulus cells. BMPR2 expression in PCOS cumulus cells might be regulated by androgens.

In Vitro Effects of Bevacizumab Treatment on Newborn Rat Retinal Cell Proliferation, Death, and Differentiation

PURPOSE. Vascular endothelial growth factor (VEGF) is an important signal protein in vertebrate nervous development, promoting neurogenesis, neuronal patterning, and glial cell growth. Bevacizumab, an anti-VEGF agent, has been extensively used for controlling pathological retinal neovascularization in adult and newborn patients, although its effect on the developing retina remains largely unknown. The purpose of this study was to investigate the effect of bevacizumab on cell death, proliferation, and differentiation in newborn rat retina. METHODS. Retinal explants of sixty 2-day-old Lister hooded rats were obtained after eye enucleation and maintained in culture media with or without bevacizumab for 2 days. Immunohistochemical staining was assessed against proliferating cell nuclear antigen (PCNA, to detect cell proliferation); caspase-3 and beclin-1 (to investigate cell death); and vimentin and glial fibrillary acidic protein (GFAP, markers of glial cells). Gene expressions were quantified by real-time reverse-transcription polymerase chain reaction. Results from treatment and control groups were compared. RESULTS. No significant difference in the staining intensity (on immunohistochemistry) of PCNA, caspase-3, beclin-1, and GFAP, or in the levels of PCNA, caspase-3, beclin-1, and vimentin mRNA was observed between the groups. However, a significant increase in vimentin levels and a significant decrease in GFAP mRNA expression were observed in bevacizumab-treated retinal explants compared with controls. CONCLUSIONS. Bevacizumab did not affect cell death or proliferation in early developing rat retina but appeared to interfere with glial cell maturation by increasing vimentin levels and downregulating GFAP gene expression. Thus, we suggest anti-VEGF agents be used with caution in developing retinal tissue. (Invest Ophthalmol Vis Sci. 2012;53:7904-7911) DOI:10.1167/iovs.12-10283

Genotoxicity assessment of water soluble fractions of biodiesel and its diesel blends using the Salmonella assay and the in vitro MicroFlow (R) kit (Litron) assay

The designation of biodiesel as an environmental-friendly alternative to diesel oil has improved its commercialization and use. However, most biodiesel environmental safety studies refer to air pollution and so far there have been very few literature data about its impacts upon other biotic systems, e.g. water, and exposed organisms. Spill simulations in water were carried out with neat diesel and biodiesel and their blends aiming at assessing their genotoxic potentials should there be contaminations of water systems. The water soluble fractions (WSF) from the spill simulations were submitted to solid phase extraction with C-18 cartridge and the extracts obtained were evaluated carrying out genotoxic and mutagenic bioassays [the Salmonella assay and the in vitro MicroFlow (R) kit (Litron) assay]. Mutagenic and genotoxic effects were observed, respectively, in the Salmonella/microsome preincubation assay and the in vitro MN test carried out with the biodiesel WSF. This interesting result may be related to the presence of pollutants in biodiesel derived from the raw material source used in its production chain. The data showed that care while using biodiesel should be taken to avoid harmful effects on living organisms in cases of water pollution. (C) 2011 Elsevier Ltd. All rights reserved.

The effect of low-level laser irradiation (In-Ga-Al-AsP - 660 nm) on melanoma in vitro and in vivo

Abstract Background It has been speculated that the biostimulatory effect of Low Level Laser Therapy could cause undesirable enhancement of tumor growth in neoplastic diseases. The aim of the present study is to analyze the behavior of melanoma cells (B16F10) in vitro and the in vivo development of melanoma in mice after laser irradiation. Methods We performed a controlled in vitro study on B16F10 melanoma cells to investigate cell viability and cell cycle changes by the Tripan Blue, MTT and cell quest histogram tests at 24, 48 and 72 h post irradiation. The in vivo mouse model (male Balb C, n = 21) of melanoma was used to analyze tumor volume and histological characteristics. Laser irradiation was performed three times (once a day for three consecutive days) with a 660 nm 50 mW CW laser, beam spot size 2 mm2, irradiance 2.5 W/cm2 and irradiation times of 60s (dose 150 J/cm2) and 420s (dose 1050 J/cm2) respectively. Results There were no statistically significant differences between the in vitro groups, except for an increase in the hypodiploid melanoma cells (8.48 ± 1.40% and 4.26 ± 0.60%) at 72 h post-irradiation. This cancer-protective effect was not reproduced in the in vivo experiment where outcome measures for the 150 J/cm2 dose group were not significantly different from controls. For the 1050 J/cm2 dose group, there were significant increases in tumor volume, blood vessels and cell abnormalities compared to the other groups. Conclusion LLLT Irradiation should be avoided over melanomas as the combination of high irradiance (2.5 W/cm2) and high dose (1050 J/cm2) significantly increases melanoma tumor growth in vivo.

Cationic nanoparticles for delivery of amphotericin B: preparation, characterization and activity in vitro

Abstract Background Particulate systems are well known to be able to deliver drugs with high efficiency and fewer adverse side effects, possibly by endocytosis of the drug carriers. On the other hand, cationic compounds and assemblies exhibit a general antimicrobial action. In this work, cationic nanoparticles built from drug, cationic lipid and polyelectrolytes are shown to be excellent and active carriers of amphotericin B against C. albicans. Results Assemblies of amphotericin B and cationic lipid at extreme drug to lipid molar ratios were wrapped by polyelectrolytes forming cationic nanoparticles of high colloid stability and fungicidal activity against Candida albicans. Experimental strategy involved dynamic light scattering for particle sizing, zeta-potential analysis, colloid stability, determination of AmB aggregation state by optical spectra and determination of activity against Candida albicans in vitro from cfu countings. Conclusion Novel and effective cationic particles delivered amphotericin B to C. albicans in vitro with optimal efficiency seldom achieved from drug, cationic lipid or cationic polyelectrolyte in separate. The multiple assembly of antibiotic, cationic lipid and cationic polyelctrolyte, consecutively nanostructured in each particle produced a strategical and effective attack against the fungus cells.

Proinflammatory profile of in vitro monocytes in the ageing is affected by lymphocytes presence

Background: Aging is associated with complex and constant remodeling of the immune function, resulting in an increasing susceptibility to infection and others diseases. The infections caused by Gram-negative microorganisms, present in nursing homes and hospitals, constitute one of the most common infections in the elderly, and are mainly combated by innate immune cells. Although the functions of innate immunity seem more preserved during aging than of adaptive immune mechanisms, two systems operate in an integrated way in the body, so that injury in one part of the immune system inevitably affects the other as they are part of a defensive network. The aim of this study was to investigate the in vitro production of proinflammatory (TNF-α, IL-6, IL-1α, CXCL-8 and MCP-1) and antiinflammatory (TGF-α and IL-10) cytokines by monocytes, stimulated or not (basal) with lipopolysaccharide, from healthy young and elderly subjects. By means of PBMCs, we also studied if cytokine profile is altered in these different patient groups, in the presence of lymphocytes, under the same experimental conditions. Results: The monocytes from elderly presented higher basal production of TNF-α, MCP-1 and lower of TGF-α than young monocytes. PBMC showed similar cytokines production, irrespective age or stimulation presence. In the presence of lymphocytes, the spontaneous production of IL-10 was higher and of TGF-α was lower than monocytes, regardless of age. After LPS-stimulation, the presence of lymphocytes resulted in increased IL-6, IL-1α, MCP-1 and IL-10 and decreased CXCL-8 and TGF-α in comparison to pure culture of monocytes from young patients. With age, the same differences were observed, except for CXCL-8 and TGF-α which production was the same between monocytes and PBMC stimulated with LPS.

CCL3 and CXCL12 production in vitro by dental pulp fibroblasts from permanent and deciduous teeth stimulated by Porphyromonas gingivalis LPS

Objective: The aim of this study was to compare the production of the chemokines CCL3 and CXCL12 by cultured dental pulp fibroblasts from permanent (PDPF) and deciduous (DDPF) teeth under stimulation by Porphyromonas gingivalis LPS (PgLPS). Material and Methods: Primary culture of fibroblasts from permanent (n=3) and deciduous (n=2) teeth were established using an explant technique. After the fourth passage, fibroblasts were stimulated by increasing concentrations of PgLPS (0 – 10 µg/mL) at 1, 6 and 24 h. The cells were tested for viability through MTT assay, and production of the chemokines CCL3 and CXCL12 was determined through ELISA. Comparisons among samples were performed using One-way ANOVA for MTT assay and Two-way ANOVA for ELISA results. Results: Cell viability was not affected by the antigen after 24 h of stimulation. PgLPS induced the production of CCL3 by dental pulp fibroblasts at similar levels for both permanent and deciduous pulp fibroblasts. Production of CXCL12, however, was significantly higher for PDPF than DDPF at 1 and 6 h. PgLPS, in turn, downregulated the production of CXCL12 by PDPF but not by DDPF. Conclusion: These data suggest that dental pulp fibroblasts from permanent and deciduous teeth may present a differential behavior under PgLPS stimulation.

In vitro cytotoxicity of white MTA, MTA Fillapex® and Portland cement on human periodontal ligament fibroblasts

The aim of this study was to compare the in vitro cytotoxicity of white mineral trioxide aggregate (MTA), MTA Fillapex® and Portland cement (PC) on human cultured periodontal ligament fibroblasts. Periodontal ligament fibroblast culture was established and the cells were used for cytotoxic tests after the fourth passage. Cell density was set at 1.25 X10 4 cells/well in 96-well plates. Endodontic material extracts were prepared by placing sealer/cement specimens (5X3mm) in 1mL of culture medium for 72 h. The extracts were then serially two-fold diluted and inserted into the cell-seeded wells for 24, 48 and 72 h. MTT assay was employed for analysis of cell viability. Cell supernatants were tested for nitric oxide using the Griess reagent system. MTA presented cytotoxic effect in undiluted extracts at 24 and 72 h. MTA Fillapex® presented the highest cytotoxic levels with important cell viability reduction for pure extracts and at ½ and ¼ dilutions. In this study, PC did not induce alterations in fibroblast viability. Nitric oxide was detected in extract-treated cell supernatants and also in the extracts only, suggesting presence of nitrite in the soluble content of the tested materials. In the present study, MTA Fillapex displayed the highest cytotoxic effect on periodontal ligament fibroblasts followed by white MTA and PC.

Diferenciação in vitro de células-tronco mesenquimais da medula óssea de cães em precursores osteogênicos

O objetivo principal da nossa pesquisa foi avaliar o potencial de diferenciação osteogênica de células-tronco mesenquimais (MSC) obtidas da medula óssea do cão. As MSC foram separadas pelo método Ficoll e cultivadas sob duas condições distintas: DMEM baixa glicose ou DMEM/F12, ambos contendo L-glutamina, 20% de SFB e antibióticos. Marcadores de MSC foram testados, confirmando células CD44+ e CD34- através da citometria de fluxo. Para a diferenciação osteogênica, as células foram submetidas a quatro diferentes condições: Grupo 1, as mesmas condições utilizadas para a cultura de células primárias com os meios DMEM baixa glicose suplementado; Grupo 2, as mesmas condições do Grupo 1, mais os indutores de diferenciação dexametasona, ácido ascórbico e b-glicerolfosfato; Grupo 3, células cultivadas com meios DMEM/F12 suplementado; e Grupo 4, nas mesmas condições que no Grupo 3, mais indutores de diferenciação de dexametasona, ácido ascórbico e b-glicerolfosfato. A diferenciação celular foi confirmada através da coloração com alizarin red e da imunomarcação com o anticorpo SP7/Osterix. Nós observamos através da coloração com alizarin red que o depósito de cálcio foi mais evidente nas células cultivadas em DMEM/F12. Além disso, usando a imunomarcação com o anticorpo SP/7Osterix obtivemos positividade em 1:6 células para o Meio DMEM/F12 comparada com 1:12 para o meio DMEM-baixa glicose. Com base nos nossos resultados concluímos que o meio DMEM/F12 é mais eficiente para a indução da diferenciação de células-tronco mesenquimais caninas em promotores osteogênicos. Este efeito provavelmente ocorre em decorrência da maior quantidade de glicose neste meio, bem como da presença de diversos aminoácidos.

Heparin and penicillamine–hypotaurine–epinephrine (PHE) solution during bovine in vitro fertilization procedures impair the quality of spermatozoa but improve normal oocyte fecundation and early embryonic development

The presence of heparin and a mixture of penicillamine, hypotaurine, and epinephrine (PHE) solution in the in vitro fertilization (IVF) media seem to be a prerequisite when bovine spermatozoa are capacitated in vitro, in order to stimulate sperm motility and acrosome reaction. The present study was designed to determine the effect of the addition of heparin and PHE during IVF on the quality and penetrability of spermatozoa into bovine oocytes and on subsequent embryo development. Sperm quality, evaluated by the integrity of plasma and acrosomal membranes and mitochondrial function, was diminished (P<0.05) in the presence of heparin and PHE. Oocyte penetration and normal pronuclear formation rates, as well as the percentage of zygotes presenting more than two pronuclei, was higher (P<0.05) in the presence of heparin and PHE. No differences were observed in cleavage rates between treatment and control (P>0.05). However, the developmental rate to the blastocyst stage was increased in the presence of heparin and PHE (P>0.05). The quality of embryos that reached the blastocyst stage was evaluated by counting the inner cell mass (ICM) and trophectoderm (TE) cell numbers and total number of cells; the percentage of ICM and TE cells was unaffected (P>0.05) in the presence of heparin and PHE (P<0.05). In conclusion, this study demonstrated that while the supplementation of IVF media with heparin and PHE solution impairs spermatozoa quality, it plays an important role in sperm capacitation, improving pronuclear formation, and early embryonic development

Importanza prognostica delle citochine e loro ruolo nell'immunomodulazione: risultati di studi sperimentali in vivo e in vitro

Citokines are proteins produced by several cell types and secreted in response to various stimuli. These molecules are able to modify the behaviour of other cells inducing activities like growth, differentiation and apoptosis. In the last years, veterinary scientists have investigated the role played by these factors; in fact, cytokines can act as intercellular communicative signals in immune response, cell damage repair and hematopoiesis. Up to date, various cytokines have been identified and in depth comprehension of their effects in physiology, pathology and therapy is an interesting field of research. This thesis aims to understand the role played by these mediators during natural or experimentally induced pathologies. In particular, it has been evaluated the genic and protein expressions of a large number of cytokines during several diseases and starting from different matrix. Considering the heterogeneity of materials used in experimentations, multiple methods and protocols of nucleic acids and proteins extractions have been standardized. Results on cytokines expression obtained from various in vitro and in vivo experimental studies have shown how important these mediators are in regulation and modulation of the host immune response also in veterinary medicine. In particular, the analysis of inflammatory and septic markers, like cytokines, has allowed a better understanding in the pathogenesis during horse Recurrent Airway Obstruction, foal sepsis, Bovine Viral Diarrhea Virus infection and dog Parvovirus infection and the effects of these agents on the host immune system. As experimentations with mice have shown, some pathologies of the respiratory and nervous system can be reduced or even erased by blocking cytokines inflammatory production. The in vitro cytokines expression evaluation in cells which are in vivo involved in the response to exogenous (like pathogens) or endogenous (as it happens during autoimmune diseases) inflammatory stimuli could represent a model for studying citokines effects during the host immune response. This has been analyzed using lymphocytes cultured with several St. aureus strains isolated from bovine mastitic milk and different colostrum products. In the first experiment different cytokines were expressed depending on enterotoxins produced, justifying a different behaviour of the microrganism in the mammal gland. In the second one, bone marrow cells derived incubated with murine lymphocytes with colostrum products have shown various cluster of differentiation expression , different proliferation and a modified cytokines profile. A better understanding of cytokine expression mechanisms will increase the know-how on immune response activated by several pathogen agents. In particular, blocking the cytokine production, the inhibition or catalyzation of the receptor binding mechanism and the modulation of signal transduction mechanism will represent a novel therapeutic strategy in veterinary medicine.

Neuroprotective activity of guanosine in an in vitro model of Alzheimer's disease

The β-Amyloid (βA) peptide is the major component of senile plaques that are one of the hallmarks of Alzheimer’s Disease (AD). It is well recognized that Aβ exists in multiple assembly states, such as soluble oligomers or insoluble fibrils, which affect neuronal viability and may contribute to disease progression. In particular, common βA-neurotoxic mechanisms are Ca2+ dyshomeostasis, reactive oxygen species (ROS) formation, altered signaling, mitochondrial dysfunction and neuronal death such as necrosis and apoptosis. Recent study shows that the ubiquitin-proteasome pathway play a crucial role in the degradation of short-lived and regulatory proteins that are important in a variety of basic and pathological cellular processes including apoptosis. Guanosine (Guo) is a purine nucleoside present extracellularly in brain that shows a spectrum of biological activities, both under physiological and pathological conditions. Recently it has become recognized that both neurons and glia also release guanine-based purines. However, the role of Guo in AD is still not well established. In this study, we investigated the machanism basis of neuroprotective effects of GUO against Aβ peptide-induced toxicity in neuronal (SH-SY5Y), in terms of mitochondrial dysfunction and translocation of phosphatidylserine (PS), a marker of apoptosis, using MTT and Annexin-V assay, respectively. In particular, treatment of SH-SY5Y cells with GUO (12,5-75 μM) in presence of monomeric βA25-35 (neurotoxic core of Aβ), oligomeric and fibrillar βA1-42 peptides showed a strong dose-dependent inhibitory effects on βA-induced toxic events. The maximum inhibition of mitochondrial function loss and PS translocation was observed with 75 μM of Guo. Subsequently, to investigate whether neuroprotection of Guo can be ascribed to its ability to modulate proteasome activity levels, we used lactacystin, a specific inhibitor of proteasome. We found that the antiapoptotic effects of Guo were completely abolished by lactacystin. To rule out the possibility that this effects resulted from an increase in proteasome activity by Guo, the chymotrypsin-like activity was assessed employing the fluorogenic substrate Z-LLL-AMC. The treatment of SH-SY5Y with Guo (75 μM for 0-6 h) induced a strong increase, in a time-dependent manner, of proteasome activity. In parallel, no increase of ubiquitinated protein levels was observed at similar experimental conditions adopted. We then evaluated an involvement of anti and pro-apoptotic proteins such as Bcl-2, Bad and Bax by western blot analysis. Interestingly, Bax levels decreased after 2 h treatment of SH-SY5Y with Guo. Taken together, these results demonstrate that Guo neuroprotective effects against βA-induced apoptosis are mediated, at least partly, via proteasome activation. In particular, these findings suggest a novel neuroprotective pathway mediated by Guo, which involves a rapid degradation of pro-apoptotic proteins by the proteasome. In conclusion, the present data, raise the possibility that Guo could be used as an agent for the treatment of AD.