Association of glycogen synthase kinase-3β with Parkinson's disease (review)

A dual druggable genome-wide siRNA and compound library screening approach identifies modulators of parkin recruitment to mitochondria

Genetic and biochemical evidence points to an association between mitochondrial dysfunction and Parkinson's disease (PD). PD-associated mutations in several genes have been identified and include those encoding PTEN-induced putative kinase 1 (PINK1) and parkin. To identify genes, pathways, and pharmacological targets that modulate the clearance of damaged or old mitochondria (mitophagy), here we developed a high-content imaging-based assay of parkin recruitment to mitochondria and screened both a druggable genome-wide siRNA library and a small neuroactive compound library. We used a multiparameter principal component analysis and an unbiased parameter-agnostic machine-learning approach to analyze the siRNA-based screening data. The hits identified in this analysis included specific genes of the ubiquitin proteasome system, and inhibition of ubiquitin-conjugating enzyme 2 N (UBE2N) with a specific antagonist, Bay 11-7082, indicated that UBE2N modulates parkin recruitment and downstream events in the mitophagy pathway. Screening of the compound library identified kenpaullone, an inhibitor of cyclin-dependent kinases and glycogen synthase kinase 3, as a modulator of parkin recruitment. Validation studies revealed that kenpaullone augments the mitochondrial network and protects against the complex I inhibitor MPP+. Finally, we used a microfluidics platform to assess the timing of parkin recruitment to depolarized mitochondria and its modulation by kenpaullone in real time and with single-cell resolution. We demonstrate that the high-content imaging-based assay presented here is suitable for both genetic and pharmacological screening approaches, and we also provide evidence that pharmacological compounds modulate PINK1-dependent parkin recruitment.

Adenosine N1-Oxide Exerts Anti-inflammatory Effects through the PI3K/Akt/GSK-3β Signaling Pathway and Promotes Osteogenic and Adipocyte Differentiation

Previously, we reported that adenosine N1-oxide (ANO), which is found in royal jelly, inhibited the secretion of inflammatory mediators by activated macrophages and reduced lethality in lipopolysaccharide (LPS)-induced endotoxin shock. Here, we examined the regulatory mechanisms of ANO on the release of pro-inflammatory cytokines, with a focus on the signaling pathways activated by toll-like receptor (TLR)4 in response to LPS. ANO inhibited both tumor necrosis factor (TNF)-α and interleukin (IL)-6 secretion from LPS-stimulated RAW264.7 cells without affecting cell proliferation. In this response, phosphorylation of mitogen-activated protein kinase (MAPK) family members (extracellular signal-regulated kinase (ERK)1/2, p38 and SAPK/c-Jun N-terminal kinase (JNK)) and nuclear factor-κB (NF-κB) p65 was not affected by treatment with ANO. In contrast, phosphorylation of Akt (Ser473) and its downstream molecule glycogen synthase kinase-3β (GSK-3β) (Ser9) was up-regulated by ANO, suggesting that ANO stimulated GSK-3β phosphorylation via phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathway. The phosphorylation of GSK-3β on Ser9 has been shown to negatively regulate the LPS-induced inflammatory response. Activation of PI3K/Akt signaling pathway has also been implicated in differentiation of mesenchymal stem cells into osteoblasts and adipocytes. As expected, ANO induced alkaline phosphatase activity and promoted calcium deposition in a mouse pre-osteoblastic MC3T3-E1 cell line. The ANO-induced differentiation into osteoblasts was abrogated by coincubation with Wortmannin. Furthermore, ANO promoted insulin/dexamethasone-induced differentiation of mouse 3T3-L1 preadipocytes into adipocytes at much lower concentrations than adenosine. The protective roles of PI3K/Akt/GSK-3β signaling pathway in inflammatory disorders have been well documented. Our data suggest that ANO may serve as a potential candidate for the treatment of inflammatory disorders. Promotion of osteogenic and adipocyte differentiation further suggests its application for regenerative medicine.

The inhibition of BDNF/TrkB/PI3K/Akt signal mediated by AG1601 promotes apoptosis in malignant glioma

Malignant glioma is the most aggressive primary brain tumor and has a poor survival rate. Even if extensive methods are preformed to treat glioma, the mortality rate is still very high. It is necessary for discovering and developing new drugs for malignant glioma treatment. AG1601 is one of AG-series drugs, including AG1031 and AG1503, and it has been optimized on the original basis. In our study, we found that AG1601 markedly inhibited proliferation and promoted C6 glioma cell apoptosis in vitro. AG1601 also reduced the size and weight of glioma in vivo. The growth ability of glioma was significantly inhibited after treatment with AG1601. It also showed that the expression levels of BDNF/TrkB/PI3K/Akt signal related proteins were obviously decreased in C6 glioma cells after treatment with AG1601 in vivo and in vitro. We also found that BDNF, as the activator of BDNF/TrkB/PI3K/Akt signal, reversed the anti-proliferation and pro-apoptosis of C6 glioma cells caused by AG1601. K252a, a specific inhibitor of TrkB, and AG1601 in combination aggravated C6 glioma cell apoptosis. These results indicate that AG1601 has good effects on the anti-proliferation and pro-apoptosis of malignant glioma via BDNF/TrkB/PI3K/Akt signal and could be considered as a potential drug in treating malignant glioma.

Neuroprotective potential of ketamine prevents developing brain structure impairment and alteration of neurocognitive function induced via isoflurane through the PI3K/AKT/GSK-3β pathway

Background

The aim of the current experimental study was to scrutinize the neuroprotective effect of ketamine on the isoflurane (iso)-induced cognitive dysfunction in rats via phosphoinositide 3 kinase (PI3K)/protein kinase B (AKT)/glycogen synthase kinase 3β (GSK-3β) pathway.

Materials and methods

Sprague-Dawley rats were used for the current experimental study. The rats were divided into six groups and rats were treated with ketamine and memantine. For the estimation of cognitive function study, we used the Morris water test. Pro-inflammatory cytokines such as IL-1β, IL-6, tumor necrosis factor-α (TNF-α), and caspase-6; the antioxidant parameters malondialdehyde, glutathione, superoxide dismutase, catalase, and protein carbonyl; acetylcholinesterase, amyloid β, and brain-derived neurotrophic factor were estimated, respectively. The protein expression of AKT, GSK-3β, p21WAF1/CIP1, and p53 was also estimated, respectively.

Results

Ketamine significantly enhanced cognitive function and showed anti-inflammatory and antioxidant effects, and exhibited the neuroprotective effect of ketamine against the isoflurane-induced cognitive impairment. Additionally, ketamine significantly (P<0.005) suppressed IL-1β, TNF-α, IL-6, caspase-6 and p21WAF1/CIP1, p53 expression and up-regulated the PI3K/AKT/GSK-3β expression in the group of iso-induced rats.

Conclusion

We can conclude that ketamine prevented the cognitive impairment induced by isoflurane anesthesia through anti-apoptotic, anti-inflammatory, and antioxidant effects via the PI3K/AKT/GSK-3β pathway.

Aqueous Extract of Davallia mariesii Attenuates 6-Hydroxydopamine-Induced Oxidative Damage and Apoptosis in B35 Cells Through Inhibition of Caspase Cascade and Activation of PI3K/AKT/GSK-3β Pathway

The medicinal ferns of Polydiaceae and Davalliaceae species are called "Gusuibu" by Chinese physicians and used as antiaging dietary medicines. Our previous report revealed that Drynaria fortunei (Polydiaceae) protected against 6-hydroxydopamine (6-OHDA)-induced oxidative damage via the PI3K/AKT pathway in B35 neuroblastoma cells. The present study compares the antioxidant phytoconstituent contents and radical scavenging capacities of five Davalliaceae species. The further aim was to clarify the protective mechanism of Davallia mariesii (DM) against 6-OHDA-induced oxidative damage and apoptosis in B35 cells. The results show that Araiostegia perdurans (AP) and DM extracts have better radical scavenging capacities against 1,1-diphenyl-2-picryhydrazyl (DPPH) and reactive oxygen species (ROS) than other Davalliaceae species. However, only DM extract inhibited 6-OHDA autoxidation under cell-free systems and increased cell viability, compared to B35 cells solely exposed to 6-OHDA. DM extract decreased apoptosis and restored mitochondrial expression in 6-OHDA-treated B35 cells. Additional data indicated that DM extract decreased intracellular ROS and nitric oxide levels generated by 6-OHDA exposure. DM extract also restored glutathione (GSH) levels and the activities of glutathione peroxidase and reductase, and then decreased the elevated malondialdehyde (MDA) levels. Finally, DM extract regulated the protein expression of the caspase cascade and PI3K/AKT/GSK-3β pathways. These results suggest that the protective mechanism of DM extract against 6-OHDA-induced oxidative damage and apoptosis might be related to its radical scavenging capacity, maintaining the mitochondrial function to inhibit the Bcl-2/caspase cascade pathway and activating intracellular antioxidant defenses (GSH recycling, HO-1 and NQO-1) by modulating the activation of the PI3K/AKT/GSK-3β pathway.

Modulation of AβPP and GSK3β by Endoplasmic Reticulum Stress and Involvement in Alzheimer's Disease

Alzheimer's disease (AD) is a dementia disease with neuronal loss and synaptic impairment. This impairment is caused, at least partly, by the generation of two main AD hallmarks, namely the hyperphosphorylated tau protein comprising neurofibrillary tangles and senile plaques containing amyloid-β (Aβ) peptides. The amyloid-β protein precursor (AβPP) and glycogen synthase kinase-3β (GSK3β) are two main proteins associated with AD and are closely correlated with these hallmarks. Recently, both of the proteins were reported to be modulated by endoplasmic reticulum stress (ERS) and are involved in the pathogenesis of AD. The mechanism of ERS plus the modulation of AβPP processing and GSK3β activity by ERS in AD are summarized and explored in this review.

Damage to dopaminergic neurons by oxidative stress in Parkinson's disease (Review)

Oxidative stress is increasingly recognized as a central event contributing to the degeneration of dopaminergic neurons in the pathogenesis of Parkinson's disease (PD). Although reactive oxygen species (ROS) production is implicated as a causative factor in PD, the cellular and molecular mechanisms linking oxidative stress with dopaminergic neuron death are complex and not well characterized. The primary insults cause the greatest production of ROS, which contributes to oxidative damage by attacking all macromolecules, including lipids, proteins and nucleic acids, leading to defects in their physiological function. Consequently, the defects in these macromolecules result in mitochondrial dysfunction and neuroinflammation, which subsequently enhance the production of ROS and ultimately neuronal damage. The interaction between these various mechanisms forms a positive feedback loop that drives the progressive loss of dopaminergic neurons in PD, and oxidative stress‑mediated neuron damage appears to serve a central role in the neurodegenerative process. Thus, understanding the cellular and molecular mechanisms by which oxidative stress contributes to the loss of dopaminergic neurons may provide a promising therapeutic approach in PD treatment.

Salidroside inhibits steroid-induced avascular necrosis of the femoral head via the PI3K/Akt signaling pathway: In vitro and in vivo studies

Dexamethasone (Dex) and other glucocorticoids are widely used to treat serious infections and immunological diseases, however they may cause steroid-induced avascular necrosis of the femoral head (SANFH). Salidroside (Sal) has demonstrated an anti-apoptotic effect on neurocytes by activating the phosphoinositide 3-kinase (PI3K)/protein kinase B (Akt) signaling pathway. In the present study, primary osteoblasts were used in vitro and in rats in vivo to determine the anti-apoptotic effect of Sal on SANFH. The result of the present study demonstrated that pretreatment with Sal increased the cell survival rate while decreasing the cell apoptosis and lactate dehydrogenase release rate. Additionally, Sal also caused the reduction of TUNEL positive cells in TUNEL staining assay. Sal decreased the expression of cleaved caspase-3, cleaved caspase-9, apoptosis regulator BAX and cytochrome C, while it increased the expression of B cell lymphoma-2 and phosphorylated-Akt in Dex-induced osteoblasts. In vivo Sal protected against SANFH in rats by decreasing the percentage of empty lacunae. The present study demonstrated that Sal alleviated Dex-induced osteoblast apoptosis by activating the PI3K/Akt signaling pathway and downregulating caspase-3 expression in osteoblasts. Sal also protected against SANFH in a rat model of SANFH by decreasing the percentage of empty lacunae. The inhibition of the mitochondrial apoptosis pathway was also involved. Further research is required to determine the full underlying mechanisms by which Sal has an effect.

Use of a special Brazilian red-light emitting railroad worm Luciferase in bioassays of NEK7 protein Kinase and Creatine Kinase

Background

Luciferases, enzymes that catalyze bioluminescent reactions in different organisms, have been extensively used for bioanalytical purposes. The most well studied bioluminescent system is that of firefly and other beetles, which depends on a luciferase, a benzothiazolic luciferin and ATP, and it is being widely used as a bioanalytical reagent to quantify ATP. Protein kinases are proteins that modify other proteins by transferring phosphate groups from a nucleoside triphosphate, usually ATP.

Methods

Here, we used a red-light emitting luciferase from Phrixotrix hirtus railroad worm to determine the activity of kinases in a coupled assay, based on luminescence that is generated when luciferase is in the presence of its substrate, the luciferin, and ATP.

Results

In this work we used, after several optimization reactions, creatine kinase isoforms as well as NEK7 protein kinase in the absence or presence of ATP analogous inhibitors  to validate this new luminescence method.

Conclusion

With this new approach we validated a luminescence method to quantify kinase activity, with different substrates and inhibition screening tests, using a novel red-light emitting luciferase as a reporter enzyme.

Electronic supplementary material

The online version of this article (doi:10.1186/s12858-017-0087-z) contains supplementary material, which is available to authorized users.

α-Synuclein binds to the ER-mitochondria tethering protein VAPB to disrupt Ca2+ homeostasis and mitochondrial ATP production

α-Synuclein is strongly linked to Parkinson’s disease but the molecular targets for its toxicity are not fully clear. However, many neuronal functions damaged in Parkinson’s disease are regulated by signalling between the endoplasmic reticulum (ER) and mitochondria. This signalling involves close physical associations between the two organelles that are mediated by binding of the integral ER protein vesicle-associated membrane protein-associated protein B (VAPB) to the outer mitochondrial membrane protein, protein tyrosine phosphatase-interacting protein 51 (PTPIP51). VAPB and PTPIP51 thus act as a scaffold to tether the two organelles. Here we show that α-synuclein binds to VAPB and that overexpression of wild-type and familial Parkinson’s disease mutant α-synuclein disrupt the VAPB-PTPIP51 tethers to loosen ER–mitochondria associations. This disruption to the VAPB-PTPIP51 tethers is also seen in neurons derived from induced pluripotent stem cells from familial Parkinson’s disease patients harbouring pathogenic triplication of the α-synuclein gene. We also show that the α-synuclein induced loosening of ER–mitochondria contacts is accompanied by disruption to Ca²⁺ exchange between the two organelles and mitochondrial ATP production. Such disruptions are likely to be particularly damaging to neurons that are heavily dependent on correct Ca²⁺ signaling and ATP.

Insensitivity of PI3K/Akt/GSK3 signaling in peripheral blood mononuclear cells of age-related macular degeneration patients

Our recent studies with cultured retinal pigment epithelium cells suggested that overexpression of interleukin 17 receptor C (IL-17RC), a phenomenon observed in peripheral blood and chorioretinal tissues with age-related macular degeneration (AMD), was associated with altered activation of phosphatidylinositide 3-kinase (PI3K), Akt, and glycogen synthase kinase 3 (GSK3). We wondered whether or not altered PI3K, Akt, and GSK3 activities could be detected in peripheral blood mononuclear cells (PBMC) obtained from AMD patients. In the patients' PBMC, absent or reduced serine-phosphorylation of GSK3α or GSK3β was observed, which was accompanied with increased phosphorylation of GSK3 substrates (e.g. CCAAT enhancer binding protein α, insulin receptor substrate 1, and TAU), indicative of enhanced GSK3 activation. In addition, decreased protein mass of PI3K85α and tyrosine-phosphorylation of PI3K50α was present in PBMC of the AMD patients, suggesting impaired PI3K activation. Moreover, abnormally lowered molecular weight forms of Akt and GSK3 were detected in PBMC of the AMD patients. These data demonstrate that despite the presence of high levels of IL-17RC, Wnt-3a and vascular endothelial growth factor, the PI3K/Akt/GSK3 signaling pathway is insensitive to these stimuli in PBMC of the AMD patients. Thus, measurement of PI3K/Akt/GSK3 expression and activity in PBMC may serve as a surrogate biomarker for AMD.

Neuroprotective Effects of Salidroside in the MPTP Mouse Model of Parkinson's Disease: Involvement of the PI3K/Akt/GSK3β Pathway

The degenerative loss through apoptosis of dopaminergic neurons in the substantia nigra pars compacta plays a primary role in the progression of Parkinson's disease (PD). Our in vitro experiments suggested that salidroside (Sal) could protect against 1-methyl-4-phenylpyridine-induced cell apoptosis in part by regulating the PI3K/Akt/GSK3β pathway. The current study aims to increase our understanding of the protective mechanisms of Sal in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropypridine- (MPTP-) induced PD mouse model. We found that pretreatment with Sal could protect against MPTP-induced increase of the time of turning downwards and climbing down to the floor. Sal also prevented MPTP-induced decrease of locomotion frequency and the increase of the immobile time. Sal provided a protection of in MPTP-induced loss of tyrosine hydroxylase-positive neurons in SNpc and the level of DA, DOPAC, and HVA in the striatum. Furthermore, Sal could increase the phosphorylation level of Akt and GSK3β, upregulate the ratio of Bcl-2/Bax, and inhibit the activation of caspase-3, caspase-6, and caspase-9. These results show that Sal prevents the loss of dopaminergic neurons and the PI3K/Akt/GSK3β pathway signaling pathway may have mediated the protection of Sal against MPTP, suggesting that Sal may be a potential candidate in neuroprotective treatment for PD.

Gsk3β and Tomm20 are substrates of the SCFFbxo7/PARK15 ubiquitin ligase associated with Parkinson's disease

Fbxo7 is a clinically relevant F-box protein, associated with both cancer and Parkinson's disease (PD). Additionally, SNPs within FBXO7 are correlated with alterations in red blood cell parameters. Point mutations within FBXO7 map within specific functional domains, including near its F-box domain and its substrate recruiting domains, suggesting that deficiencies in SCF^Fbxo7/PARK15 ubiquitin ligase activity are mechanistically linked to early-onset PD. To date, relatively few substrates of the ligase have been identified. These include HURP (hepatoma up-regulated protein), whose ubiquitination results in proteasome-mediated degradation, and c-IAP1 (inhibitor of apoptosis protein 1), TNF receptor-associated factor 2 (TRAF2), and NRAGE, which are not destabilized as a result of ubiquitination. None of these substrates have been linked directly to PD, nor has it been determined whether they would directly engage neuronal cell death pathways. To discover ubiquitinated substrates of SCF^Fbxo7 implicated more directly in PD aetiology, we conducted a high-throughput screen using protein arrays to identify new candidates. A total of 338 new targets were identified and from these we validated glycogen synthase kinase 3β (Gsk3β), which can phosphorylate α-synuclein, and translocase of outer mitochondrial membrane 20 (Tomm20), a mitochondrial translocase that, when ubiquitinated, promotes mitophagy, as SCF^Fbxo7 substrates both in vitro and in vivo. Ubiquitin chain restriction analyses revealed that Fbxo7 modified Gsk3β using K63 linkages. Our results indicate that Fbxo7 negatively regulates Gsk3β activity, rather than its levels or localization. In addition, Fbxo7 ubiquitinated Tomm20, and its levels correlated with Fbxo7 expression, indicating a stabilizing effect. None of the PD-associated mutations in Fbxo7 impaired Tomm20 ubiquitination. Our findings demonstrate that SCF^Fbxo7 has an impact directly on two proteins implicated in pathological processes leading to PD.

Chronic over-nutrition and dysregulation of GSK3 in diseases

Loss of cellular response to hormonal regulation in maintaining metabolic homeostasis is common in the process of aging. Chronic over-nutrition may render cells insensitive to such a hormonal regulation owing to overstimulation of certain signaling pathways, thus accelerating aging and causing diseases. The glycogen synthase kinase 3 (GSK3) plays a pivotal role in relaying various extracellular and intracellular regulatory signals critical to cell growth, survival, regeneration, or death. The main signaling pathway regulating GSK3 activity through serine-phosphorylation is the phosphoinositide 3-kinase (PI3K)/phosphoinositide-dependent kinase-1 (PDK1)/Akt relay that catalyzes serine-phosphorylation and thus inactivation of GSK3. In addition, perilipin 2 (PLIN2) has recently been shown to regulate GSK3 activation through direct association with GSK3. This review summarizes current understanding on environmental and nutritional factors contributing to GSK3 regulation (or dysregulation) through the PI3K/PDK1/Akt/GSK3 axis, and highlights the newly discovered role that PLIN2 plays in regulating GSK3 activity and GSK3 downstream pathways.

Glycogen Synthase Kinase-3 (GSK-3)-Targeted Therapy and Imaging

Glycogen synthase kinase-3 (GSK-3) is associated with various key biological processes, including glucose regulation, apoptosis, protein synthesis, cell signaling, cellular transport, gene transcription, proliferation, and intracellular communication. Accordingly, GSK-3 has been implicated in a wide variety of diseases and specifically targeted for both therapeutic and imaging applications by a large number of academic laboratories and pharmaceutical companies. Here, we review the structure, function, expression levels, and ligand-binding properties of GSK-3 and its connection to various diseases. A selected list of highly potent GSK-3 inhibitors, with IC₅₀ <20 nM for adenosine triphosphate (ATP)-competitive inhibitors and IC₅₀ <5 μM for non-ATP-competitive inhibitors, were analyzed for structure activity relationships. Furthermore, ubiquitous expression of GSK-3 and its possible impact on therapy and imaging are also highlighted. Finally, a rational perspective and possible route to selective and effective GSK-3 inhibitors is discussed.

A new look at an old drug: neuroprotective effects and therapeutic potentials of lithium salts

Increasing evidence highlights bipolar disorder as being associated with impaired neurogenesis, cellular plasticity, and resiliency, as well as with cell atrophy or loss in specific brain regions. This has led most recent research to focus on the possible neuroprotective effects of medications, and particularly interesting findings have emerged for lithium. A growing body of evidence from preclinical in vitro and in vivo studies has in fact documented its neuroprotective effects from different insults acting on cellular signaling pathways, both preventing apoptosis and increasing neurotrophins and cell-survival molecules. Furthermore, positive effects of lithium on neurogenesis, brain remodeling, angiogenesis, mesenchymal stem cells functioning, and inflammation have been revealed, with a key role played through the inhibition of the glycogen synthase kinase-3, a serine/threonine kinase implicated in the pathogenesis of many neuropsychiatric disorders. These recent evidences suggest the potential utility of lithium in the treatment of neurodegenerative diseases, neurodevelopmental disorders, and hypoxic-ischemic/traumatic brain injury, with positive results at even lower lithium doses than those traditionally considered to be antimanic. The aim of this review is to briefly summarize the potential benefits of lithium salts on neuroprotection and neuroregeneration, emphasizing preclinical and clinical evidence suggesting new therapeutic potentials of this drug beyond its mood stabilizing properties.

Substance P prevents 1-methyl-4-phenylpyridinium-induced cytotoxicity through inhibition of apoptosis via neurokinin-1 receptors in MES23.5 cells

[Sar9, Met(O2)11] termed Substance P (SP), is an effective and selective agonist for the neurokinin‑1 (NK‑1) receptors, which are synthetic peptides, similar in structure to SP. SP is an important neurotransmitter or neuromodulator mediated by neurokinin receptors, namely the SP receptor in the central nervous system. The excitatory effects induced by SP may be selectively inhibited by a neurokinin‑1 receptor antagonist, such as SR140333B. It has been proposed that Parkinson's disease (PD) is primarily caused by the loss of trophic peptidergic neurotransmitter, possibly SP, which may lead to the degeneration of neurons. In previous studies, 1‑methyl‑4‑phenylpyridinium (MPP+) has been frequently utilized to establish animal or cell models of PD. In the present study, to further investigate the effects of SP in PD, MPP+ was employed to investigate the promising anti‑apoptotic effects of SP, and examine the underlying mechanisms of the pathology in the MES23.5 dopaminergic cell line. The results indicated that MPP+‑triggered apoptosis was prevented by treatment with SP. SP treatment also decreased the MPP+‑triggered Ca2+ influx, caspase‑3 re‑activity, reactive oxygen species production and mitochondrial membrane potential decrease. Treatment with MPP+ also induced phosphorylation of c‑Jun N‑terminal kinase and p38 mitogen‑activated protein kinase. In addition, treatment with SP inhibited the MPP+‑triggered neurotoxicity in MES23.5 cells. However, no changes were observed in SR140333B+SP+MPP+‑treated MES23.5 cell lines. In conclusion, SP could protect the cells from MPP+‑induced cytotoxicity by inhibiting the apoptosis via NK-1 receptors.

Resveratrol: A Focus on Several Neurodegenerative Diseases

Molecules of the plant world are proving their effectiveness in countering, slowing down, and regressing many diseases. The resveratrol for its intrinsic properties related to its stilbene structure has been proven to be a universal panacea, especially for a wide range of neurodegenerative diseases. This paper evaluates (in vivo and in vitro) the various molecular targets of this peculiar polyphenol and its ability to effectively counter several neurodegenerative disorders such as Parkinson's, Alzheimer's, and Huntington's diseases and amyotrophic lateral sclerosis. What emerges is that, in the deep heterogeneity of the pathologies evaluated, resveratrol through a convergence on the protein targets is able to give therapeutic responses in neuronal cells deeply diversified not only in morphological structure but especially in their function performed in the anatomical district to which they belong.

Dock GEFs and their therapeutic potential: neuroprotection and axon regeneration

The dedicator of cytokinesis (Dock) family is composed of atypical guanine exchange factors (GEFs) that activate the Rho GTPases Rac1 and Cdc42. Rho GTPases are best documented for their roles in actin polymerization and they regulate important cellular functions, including morphogenesis, migration, neuronal development, and cell division and adhesion. To date, 11 Dock family members have been identified and their roles have been reported in diverse contexts. There has been increasing interest in elucidating the roles of Dock proteins in recent years and studies have revealed that they are potential therapeutic targets for various diseases, including glaucoma, Alzheimer's disease, cancer, attention deficit hyperactivity disorder and combined immunodeficiency. Among the Dock proteins, Dock3 is predominantly expressed in the central nervous system and recent studies have revealed that Dock3 plays a role in protecting retinal ganglion cells from neurotoxicity and oxidative stress as well as in promoting optic nerve regeneration. In this review, we discuss the current understanding of the 11 Dock GEFs and their therapeutic potential, with a particular focus on Dock3 as a novel target for the treatment of glaucoma and other neurodegenerative diseases.

Prenatal alcohol exposure alters p35, CDK5 and GSK3β in the medial frontal cortex and hippocampus of adolescent mice

Fetal alcohol spectrum disorders (FASDs) are the number one cause of preventable mental retardation. An estimated 2-5% of children are diagnosed as having a FASD. While it is known that children prenatally exposed to alcohol experience cognitive deficits and a higher incidence of psychiatric illness later in life, the pathways underlying these abnormalities remain uncertain. GSK3β and CDK5 are protein kinases that are converging points for a vast number of signaling cascades, including those controlling cellular processes critical to learning and memory. We investigated whether levels of GSK3β and CDK5 are affected by moderate prenatal alcohol exposure (PAE), specifically in the hippocampus and medial frontal cortex of the adolescent mouse. In the present work we utilized immunoblotting techniques to demonstrate that moderate PAE increased hippocampal p35 and β-catenin, and decreased total levels of GSK3β, while increasing GSK3β Ser9 and Tyr216 phosphorylation. Interestingly, different alterations were seen in the medial frontal cortex where p35 and CDK5 were decreased and increased total GSK3β was accompanied by reduced Tyr216 of the enzyme. These results suggest that kinase dysregulation during adolescence might be an important contributing factor to the effects of PAE on hippocampal and medial frontal cortical functioning; and by extension, that global modulation of these kinases may produce differing effects depending on brain region.