Peripheral expression of key regulatory kinases in Alzheimer's disease and Parkinson's disease

Rational Design of Dual-Functionalized Gd@C82 Nanoparticles to Relieve Neuronal Cytotoxicity in Alzheimer's Disease via Inhibition of Aβ Aggregation

The accumulation of amyloid-β (Aβ) peptides is a major hallmark of Alzheimer's disease (AD) and plays a crucial role in its pathogenesis. Particularly, the structured oligomeric species rich in β-sheet formations were implicated in neuronal organelle damage. Addressing this formidable challenge requires identifying candidates capable of inhibiting peptide aggregation or disaggregating preformed oligomers for effective antiaggregation-based AD therapy. Here, we present a dual-functional nanoinhibitor meticulously designed to target the aggregation driving force and amyloid fibril spatial structure. Leveraging the exceptional structural stability and facile tailoring capability of endohedral metallofullerene Gd@C82, we introduce desired hydrogen-binding sites and charged groups, which are abundant on its surface for specific designs. Impressively, these designs endow the resultant functionalized-Gd@C82 nanoparticles (f-Gd@C82 NPs) with high capability of redirecting peptide self-assembly toward disordered, off-pathway species, obstructing the early growth of protofibrils, and disaggregating the preformed well-ordered protofibrils or even mature Aβ fibrils. This results in considerable alleviation of Aβ peptide-induced neuronal cytotoxicity, rescuing neuronal death and synaptic loss in primary neuron models. Notably, these modifications significantly improved the dispersibility of f-Gd@C82 NPs, thus substantially enhancing its bioavailability. Moreover, f-Gd@C82 NPs demonstrate excellent cytocompatibility with various cell lines and possess the ability to penetrate the blood-brain barrier in mice. Large-scale molecular dynamics simulations illuminate the inhibition and disaggregation mechanisms. Our design successfully overcomes the limitations of other nanocandidates, which often overly rely on hydrophobic interactions or photothermal conversion properties, and offers a viable direction for developing anti-AD agents through the inhibition and even reversal of Aβ aggregation.

Ser9p-GSK3β Modulation Contributes to the Protective Effects of Vitamin C in Neuroinflammation

BACKGROUND

The prolonged activation of microglia and excessive production of pro-inflammatory cytokines can lead to chronic neuroinflammation, which is an important pathological feature of Parkinson's disease (PD). We have previously reported the protective effect of Vitamin C (Vit C) on a mouse model of PD. However, its effect on microglial functions in neuroinflammation remains to be clarified. Glycogen synthase kinase 3β (GSK3β) is a serine/threonine kinase having a role in driving inflammatory responses, making GSK3β inhibitors a promising target for anti-inflammatory research.

METHODS

In this study, we investigated the possible involvement of GSK3β in Vit C neuroprotective effects by using a well-known 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced animal model of PD and a cellular model of neuroinflammation, represented by Lipopolysaccharide (LPS)-activated BV-2 microglial cells.

RESULTS

We demonstrated the ability of Vit C to decrease the expression of different mediators involved in the inflammatory responses, such as TLR4, p-IKBα, and the phosphorylated forms of p38 and AKT. In addition, we demonstrated for the first time that Vit C promotes the GSK3β inhibition by stimulating its phosphorylation at Ser9.

CONCLUSION

This study evidenced that Vit C exerts an anti-inflammatory function in microglia, promoting the upregulation of the M2 phenotype through the activation of the Wnt/β-catenin signaling pathway.

Parkinson's Disease and MicroRNAs: A Duel Between Inhibition and Stimulation of Apoptosis in Neuronal Cells

Parkinson's disease (PD) is one of the most prevalent diseases of central nervous system that is caused by degeneration of the substantia nigra's dopamine-producing neurons through apoptosis. Apoptosis is regulated by initiators' and executioners' caspases both in intrinsic and extrinsic pathways, further resulting in neuronal damage. In that context, targeting apoptosis appears as a promising therapeutic approach for treating neurodegenerative diseases. Non-coding RNAs-more especially, microRNAs, or miRNAs-are a promising target for the therapy of neurodegenerative diseases because they are essential for a number of cellular processes, including signaling, apoptosis, cell proliferation, and gene regulation. It is estimated that a substantial portion of coding genes (more than 60%) are regulated by miRNAs. These small regulatory molecules can have wide-reaching consequences on cellular processes like apoptosis, both in terms of intrinsic and extrinsic pathways. Furthermore, it was recommended that a disruption in miRNA expression levels could also result in perturbation of typical apoptosis pathways, which may be a factor in certain diseases like PD. The latest research on miRNAs and their impact on neural cell injury in PD models by regulating the apoptosis pathway is summarized in this review article. Furthermore, the importance of lncRNA/circRNA-miRNA-mRNA network for regulating apoptosis pathways in PD models and treatment is explored. These results can be utilized for developing new strategies in PD treatment.

Study on correlations of BDNF, PI3K, AKT and CREB levels with depressive emotion and impulsive behaviors in drug-naïve patients with first-episode schizophrenia

BACKGROUND

The pathogenesis of schizophrenia is still unknown. Nearly a half of schizophrenic patients have depressive symptoms and even some impulsive behaviors. The definite diagnosis of schizophrenia is an immense challenge. Molecular biology plays an essential role in the research on the pathogenesis of schizophrenia.

OBJECTIVE

This study aims to analyze the correlations of serum protein factor levels with depressive emotion and impulsive behaviors in drug-naïve patients with first-episode schizophrenia.

METHODS

Seventy drug-naïve patients with first-episode schizophrenia and sixty-nine healthy volunteers from the health check center in the same period participated in this study. In both the patient group and control group, brain-derived neurotrophic factor (BDNF), phosphatidylin-ositol-3-kinase (PI3K), protein kinase B (AKT), and cAMP-response element binding protein (CREB) levels in the peripheral blood were tested by enzyme-linked immunosorbent assay (ELISA). The depressive emotion and impulsive behaviors were evaluated with Chinese versions of the Calgary Depression Scale for Schizophrenia (CDSS) and Short UPPS-P Impulsive Behavior Scale (S-UPPS-P), respectively.

RESULTS

The serum levels of BDNF, PI3K, and CREB in the patient group were lower than those in the control group, while AKT level, total CDSS score and total S-UPPS-P score were all higher. In the patient group, total CDSS score, and total S-UPPS-P score were both correlated negatively with BDNF, PI3K, and CREB levels but positively with AKT level, and the lack-of-premeditation (PR) sub-scale score was not significantly correlated with BDNF, PI3K, AKT, and CREB levels.

CONCLUSION

Our study results showed that the peripheral blood levels of BDNF, PI3K, AKT, and CREB in drug-naïve patients with first-episode schizophrenia were significantly different from those in the control group. The levels of these serum protein factors are promising biomarkers to predict schizophrenic depression and impulsive behaviors.

Identification of a novel pathway in sporadic Amyotrophic Lateral Sclerosis mediated by the long non-coding RNA ZEB1-AS1

BACKGROUND

Deregulation of transcription in the pathogenesis of sporadic Amyotrophic Lateral Sclerosis (sALS) is taking central stage with RNA-sequencing analyses from sALS patients tissues highlighting numerous deregulated long non-coding RNAs (lncRNAs). The oncogenic lncRNA ZEB1-AS1 is strongly downregulated in peripheral blood mononuclear cells of sALS patients. In addition, in cancer-derived cell lines, ZEB1-AS1 belongs to a negative feedback loop regulation with hsa-miR-200c, acting as a molecular sponge for this miRNA. The role of the lncRNA ZEB1-AS1 in sALS pathogenesis has not been characterized yet, and its study could help identifying a possible disease-modifying target.

METHODS

the implication of the ZEB1-AS1/ZEB1/hsa-miR-200c/BMI1 pathway was investigated in multiple patients-derived cellular models (patients-derived peripheral blood mononuclear cells and induced pluripotent stem cells-derived neural stem cells) and in the neuroblastoma cell line SH-SY5Y, where its function was inhibited via RNA interference. Molecular techniques such as Real Time PCR, Western Blot and Immunofluorescence were used to assess the pathway dysregulation.

RESULTS

Our results show a dysregulation of a signaling pathway involving ZEB1-AS1/hsa-miR-200c/β-Catenin in peripheral blood mononuclear cells and in induced pluripotent stem cells-derived neural stem cells from sALS patients. These results were validated in vitro on the cell line SH-SY5Y with silenced expression of ZEB1-AS1. Moreover, we found an increase for ZEB1-AS1 during neural differentiation with an aberrant expression of β-Catenin, highlighting also its aggregation and possible impact on neurite length.

CONCLUSIONS

Our results support and describe the role of ZEB1-AS1 pathway in sALS and specifically in neuronal differentiation, suggesting that an impairment of β-Catenin signaling and an alteration of the neuronal phenotype are taking place.

PI3K polymorphism in patients with sporadic Parkinson's disease

Parkinson's disease (PD) is a common irreversible neurodegenerative disease associated with cognitive impairment. To investigate the serum level of phosphatidylinositol-3-kinase (PI3K) and the distribution of the genotypes and alleles of 3 PI3K single-nucleotide polymorphisms (RS37,30,087, RS37,30,088, and RS37,30,089) in PD patients with different clinical characteristics. A total of 54 PD patients and 50 healthy individuals were recruited. The serum PI3K level was measured using the enzyme-linked immunosorbent assay. The severity of PD was assessed using the modified Hoehn-Yahr scale. The cognitive function of PD patients was evaluated using the Mini-Mental State Examination scale and the Montreal Cognitive Assessment. The distribution of the alleles and genotypes of PI3K single-nucleotide polymorphisms (SNPs) was calculated using the Hardy-Weinberg equilibrium. PD patients showed a significantly higher serum level of PI3K compared to healthy individuals. Increased serum PI3K level was observed in PD patients with more severe disease, longer disease duration, and impaired cognitive function. Additionally, no significant differences were observed in the distributions of the genotypes and alleles of 3 PI3K SNPs between PD patients with normal cognitive function and those with cognitive impairment. PD patients with different levels of disease severity, disease duration, and cognitive function had significantly different serum levels of PI3K. However, the PI3K SNPs in patients with normal cognitive function were not significantly different from those in patients with cognitive impairment. These findings contribute to a better understanding of the roles of PI3K and SNPs of the PI3K gene in PD.

GSK3 Is a Central Player in Retinal Degenerative Diseases but a Challenging Therapeutic Target

Glycogen synthase kinase 3 (GSK3) is a key regulator of many cellular signaling processes and performs a wide range of biological functions in the nervous system. Due to its central role in numerous cellular processes involved in cell degeneration, a rising number of studies have highlighted the interest in developing therapeutics targeting GSK3 to treat neurodegenerative diseases. Although recent works strongly suggest that inhibiting GSK3 might also be a promising therapeutic approach for retinal degenerative diseases, its full potential is still under-evaluated. In this review, we summarize the literature on the role of GSK3 on the main cellular functions reported as deregulated during retinal degeneration, such as glucose homeostasis which is critical for photoreceptor survival, or oxidative stress, a major component of retinal degeneration. We also discuss the interest in targeting GSK3 for its beneficial effects on inflammation, for reducing neovascularization that occurs in some retinal dystrophies, or for cell-based therapy by enhancing Müller glia cell proliferation in diseased retina. Together, although GSK3 inhibitors hold promise as therapeutic agents, we highlight the complexity of targeting such a multitasked kinase and the need to increase our knowledge of the impact of reducing GSK3 activity on these multiple cellular pathways and biological processes.

Glycogen Synthase Kinase-3 Inhibitors: Preclinical and Clinical Focus on CNS-A Decade Onward

The protein kinase, GSK-3, participates in diverse biological processes and is now recognized a promising drug discovery target in treating multiple pathological conditions. Over the last decade, a range of newly developed GSK-3 inhibitors of diverse chemotypes and inhibition modes has been developed. Even more conspicuous is the dramatic increase in the indications that were tested from mood and behavior disorders, autism and cognitive disabilities, to neurodegeneration, brain injury and pain. Indeed, clinical and pre-clinical studies were largely expanded uncovering new mechanisms and novel insights into the contribution of GSK-3 to neurodegeneration and central nerve system (CNS)-related disorders. In this review we summarize new developments in the field and describe the use of GSK-3 inhibitors in the variety of CNS disorders. This remarkable volume of information being generated undoubtedly reflects the great interest, as well as the intense hope, in developing potent and safe GSK-3 inhibitors in clinical practice.

Neural tube defects: role of lithium carbonate exposure in embryonic neural development in a murine model

BACKGROUND

Lithium carbonate (Li₂CO₃) is widely used in the treatment of clinical-affective psychosis. Exposure to Li₂CO₃ during pregnancy increases the risk of neural tube defects (NTDs) in offspring, which are severe birth defects of the central nervous system. The mechanism of Li₂CO₃-induced NTDs remains unclear.

METHODS

C57BL/6 mice were injected with different doses of Li₂CO₃ intraperitoneally on gestational day 7.5 (GD7.5), and embryos collected at GD11.5 and GD13.5. The mechanisms of Li₂CO₃ exposure-induced NTDs were determined utilizing immunohistochemistry, western blotting, EdU imaging, enzymatic method, gas chromatography-mass spectrometry (GC-MS), ELISA and HE staining.

RESULTS

The NTDs incidence was 33.7% following Li₂CO₃ exposure. Neuroepithelial cell proliferation and phosphohistone H3 level were significantly increased in NTDs embryos, compared with control group (P < 0.01), while the expressing levels of p53 and caspase-3 were significantly decreased. IMPase and GSK-3β activity was inhibited in Li₂CO₃-treated maternal and embryonic neural tissues (P < 0.01 and P < 0.05, respectively), along with decreased levels of inositol and metabolites, compared with control groups (P < 0.01).

CONCLUSIONS

Lithium-induced NTDs model in C57BL/6 mice was established. Enhanced cell proliferation and decreased apoptosis following lithium exposure were closely associated with the impairment of inositol biosynthesis, which may contribute to lithium-induced NTDs.

IMPACT

Impairment of inositol biosynthesis has an important role in lithium exposure-induced NTDs in mice model. Lithium-induced NTDs model on C57BL/6 mice was established. Based on this NTDs model, lithium-induced impairment of inositol biosynthesis resulted in the imbalance between cell proliferation and apoptosis, which may contribute to lithium-induced NTDs. Providing evidence to further understand the molecular mechanisms of lithium-induced NTDs and enhancing its primary prevention.

Different miRNA Profiles in Plasma Derived Small and Large Extracellular Vesicles from Patients with Neurodegenerative Diseases

Identifying biomarkers is essential for early diagnosis of neurodegenerative diseases (NDs). Large (LEVs) and small extracellular vesicles (SEVs) are extracellular vesicles (EVs) of different sizes and biological functions transported in blood and they may be valid biomarkers for NDs. The aim of our study was to investigate common and different miRNA signatures in plasma derived LEVs and SEVs of Alzheimer’s disease (AD), Parkinson’s disease (PD), Amyotrophic Lateral Sclerosis (ALS) and Fronto-Temporal Dementia (FTD) patients. LEVs and SEVs were isolated from plasma of patients and healthy volunteers (CTR) by filtration and differential centrifugation and RNA was extracted. Small RNAs libraries were carried out by Next Generation Sequencing (NGS). MiRNAs discriminate all NDs diseases from CTRs and they can provide a signature for each NDs. Common enriched pathways for SEVs were instead linked to ubiquitin mediated proteolysis and Toll-like receptor signaling pathways and for LEVs to neurotrophin signaling and Glycosphingolipid biosynthesis pathway. LEVs and SEVs are involved in different pathways and this might give a specificity to their role in the spreading of the disease. The study of common and different miRNAs transported by LEVs and SEVs can be of great interest for biomarker discovery and for pathogenesis studies in neurodegeneration.

Metabolic determinants of leukocyte pathogenicity in neurological diseases

Neuroinflammatory and neurodegenerative diseases are characterized by the recruitment of circulating blood-borne innate and adaptive immune cells into the central nervous system (CNS). These leukocytes sustain the detrimental response in the CNS by releasing pro-inflammatory mediators that induce activation of local glial cells, blood-brain barrier (BBB) dysfunction, and neural cell death. However, infiltrating peripheral immune cells could also dampen CNS inflammation and support tissue repair. Recent advances in the field of immunometabolism demonstrate the importance of metabolic reprogramming for the activation and functionality of such innate and adaptive immune cell populations. In particular, an increasing body of evidence suggests that the activity of metabolites and metabolic enzymes could influence the pathogenic potential of immune cells during neuroinflammatory and neurodegenerative disorders. In this review, we discuss the role of intracellular metabolic cues in regulating leukocyte-mediated CNS damage in Alzheimer's and Parkinson's disease, multiple sclerosis and stroke, highlighting the therapeutic potential of drugs targeting metabolic pathways for the treatment of neurological diseases.

GSK-3β Contributes to Parkinsonian Dopaminergic Neuron Death: Evidence From Conditional Knockout Mice and Tideglusib

Glycogen synthase kinase-3 (GSK-3) dysregulation has been implicated in nigral dopaminergic neurodegeneration, one of the main pathological features of Parkinson’s disease (PD). The two isoforms, GSK-3α and GSK-3β, have both been suggested to play a detrimental role in neuronal death. To date, several studies have focused on the role of GSK-3β on PD pathogenesis, while the role of GSK-3α has been largely overlooked. Here, we report in situ observations that both GSK-3α and GSK-3β are dephosphorylated at a negatively acting regulatory serine, indicating kinase activation, selectively in nigral dopaminergic neurons following exposure of mice to 1-methyl-4-pheny-1,2,3,6-tetrahydropyridine (MPTP). To identify whether GSK-3α and GSK-3β display functional redundancy in regulating parkinsonian dopaminergic cell death, we analysed dopaminergic neuron-specific Gsk3a null (Gsk3a^ΔDat) and Gsk3b null (Gsk3b^ΔDat) mice, respectively. We found that Gsk3b^ΔDat, but not Gsk3a^ΔDat, showed significant resistance to MPTP insult, revealing non-redundancy of GSK-3α and GSK-3β in PD pathogenesis. In addition, we tested the neuroprotective effect of tideglusib, the most clinically advanced inhibitor of GSK-3, in the MPTP model of PD. Administration of higher doses (200 mg/kg and 500 mg/kg) of tideglusib exhibited significant neuroprotection, whereas 50 mg/kg tideglusib failed to prevent dopaminergic neurodegeneration from MPTP toxicity. Administration of 200 mg/kg tideglusib improved motor symptoms of MPTP-treated mice. Together, these data demonstrate GSK-3β and not GSK-3α is critical for parkinsonian neurodegeneration. Our data support the view that GSK-3β acts as a potential therapeutic target in PD and tideglusib would be a candidate drug for PD neuroprotective therapy.

Regulation of Protein Synthesis and Apoptosis in Lymphocytes of Parkinson Patients: The Effect of Dopaminergic Treatment

BACKGROUND

Parkinson disease (PD) is a neurodegenerative disorder characterized by progressive degeneration of the dopaminergic neurons in the substantia nigra, presumably due to increased apoptosis. In previous studies, we showed altered expression of proteins involved in mammalian target of rapamycin (mTOR) antiapoptotic and double-stranded RNA-dependent protein kinase (PKR) apoptotic pathways of translational control in experimental cellular and animal models of PD.

RESULTS

In this work, our results showed clear modifications in the expression of kinases involved in mTOR and PKR apoptosis pathways, in lymphocytes of PD patients treated or not with anti-PD treatment (levodopa), which confirmed the role played by apoptosis in the pathogenesis of this disease and the positive effect of treatment with medication on this parameter. Others proteins involved in apo-ptosis were also evaluated in lymphocytes of patients as the expression of the peripheral benzodiazepine receptor and caspase-3.

CONCLUSION

Translational control is altered in PD and hence its evaluation in peripheral blood mononuclear cells may serve as an early marker of apoptosis and indicate the efficacy of the dopaminergic treatment.

Modified level of miR-376a is associated with Parkinson's disease

Parkinson's disease (PD) is a frequent progressive neurodegenerative disorder. Impaired mitochondrial function is a major feature of sporadic PD. Some susceptibility or causative genes detected in PD are strongly associated with mitochondrial dysfunction including PGC1α, TFAM and GSK3β. microRNAs (miRNAs) are non‐coding RNAs whose altered levels are proven in disparate PD models and human brains. Therefore, the aim of this study was to detect modulations of miRs upstream of PGC1α, TFAM and GSK3β in association with PD onset and progress. In this study, a total of 33 PD subjects and 25 healthy volunteers were recruited. Candidate miRNA (miR‐376a) was selected through target prediction tools and literature survey. Chronic and acute in vitro PD models were created by MPP⁺‐intoxicated SHSY5Y cells. The levels of miR‐376a and aforementioned genes were assessed by RT‐qPCR. The expression of target genes was decreased in chronic model while there were dramatically up‐regulated levels of those genes in acute model of PD. miR‐376a was strongly altered in both acute and chronic PD models as well as PBMCs of PD patients. Our results also showed overexpression of PGC1α, and TFAM in PBMCs is inversely correlated with down‐regulation of miR‐376a, suggesting that miR‐376a possibly has an impact on PD pathogenesis through regulation of these genes which are involved in mitochondrial function. miR‐376a expression in PD‐derived PBMCs was also correlated with disease severity and may serve as a potential biomarker for PD diagnosis. This is the first study showing altered levels of miR‐376a in PD models and PBMCs, suggesting the probable role of this miRNA in PD pathogenesis. The present study also proposed TFAM and PGC1α as target genes of miR‐376a for the first time, through which it possibly can exert its impact on PD pathogenesis.

Effects and mechanism of epigallocatechin-3-gallate on apoptosis and mTOR/AKT/GSK-3β pathway in substantia nigra neurons in Parkinson rats

The aim of this study is to investigate the protective effect of epigallocatechin-3-gallate (EGCG) on apoptosis and mTOR/AKT/GSK-3β pathway in substantia nigra neurons in 6-dopamine-induced Parkinson rats. A total of 30 healthy male SD rats were randomly divided into control group, the Parkinson model group, and Parkinson model+EGCG treatment group. The model and EGCG groups were injected into the right striatum with 6-OHDA to establish the Parkinson model, and the control group was injected with saline only. The EGCG group was intragastrically administered with EGCG 50 mg/kg daily for 4 weeks. The rats' turns, speed, and left forelimb usage; neuron apoptosis by TUNEL; and the α-synuclein protein expression in substantia nigra by immunohistochemical staining were studied. Western blotting was used to detect the relative protein (mTOR, AKT and GSK-3β) expressions. Compared with the model group, the EGCG group significantly reduced the rotation speed; increased the left forelimb usage (P<0.01); reduced the neuron apoptosis (P<0.01); decreased α-synuclein expression (P<0.01); and decreased the mTOR, AKT, and GSK-3β protein expressions (P<0.01). EGCG can reduce neuron cell apoptosis in substantia nigra neurons in 6-OHDA-induced Parkinson rats. The mechanism might be related to mTOR/AKT/GSK-3β activation.

Peripheral BDNF/TrkB protein expression is decreased in Parkinson's disease but not in Essential tremor

BDNF-to-TrkB signaling pathways plays an important role in the long-term maintenance of the nigrostriatal system and that its deficiency may contribute to the onset and progression of Parkinson's disease (PD). To our knowledge this is the first study to investigate the expression of the brain-derived neurotrophic factor (BDNF) and phosphorylation status of TrkB in peripheral blood lymphocytes of 28 PD and 28 Essential tremor (ET) patients and 28 healthy controls using western blot analysis. Compared with controls, no significant difference of BDNF and total and phosphorylated TrkB levels were observed in ET, whereas BDNF and phosphorylated TrkB levels were significantly decreased in the PD groups (p < 0.001). Interestingly, BDNF and phosphorylated TrkB levels were positively correlated with disease duration, UPDRS score, Hoehn-Yahr staging, as well as L-DOPA medication in PD patients. These results suggest that the decreased peripheral alteration of BDNF/TrkB levels found in patients with PD is directly related to the dopaminergic neurons neurodegeneration and that decreased expression of BDNF/TrkB may lead to the development of innovative biomarkers of PD, whereas the increased level of BDNF and phosphorylated TrkB at advanced stages may due to L-DOPA medication.

Blood-Based Kinase Assessments in Alzheimer's Disease

Alzheimer’s disease (AD) is marked by memory disturbances followed by aphasia, apraxia and agnosia. Brain lesions include the accumulation of the amyloid peptide in extracellular plaques, neurofibrillary tangles with abnormally phosphorylated tau protein and synaptic and neuronal loss. New findings have suggested that brain lesions could occur one or two decades before the first clinical signs. This asymptomatic preclinical phase could be an opportunity to put in place a secondary prevention but the detection of these brain lesions can only be achieved so far by cerebrospinal fluid (CSF) evaluation or molecular amyloid and tau PET imaging. There is an urgent need to find out simple and easily accessible new biomarkers to set up an efficient screening in adult and aging population. Neuropathological and biochemical studies have revealed that abnormal accumulations of potentially toxic kinases are present in the brains of AD patients. Kinase activation leads to abnormal tau phosphorylation, amyloid production, apoptosis and neuroinflammation. Increased levels of these kinases are present in the CSF of mild cognitive impairment (MCI) and AD patients. Over the last years the search for abnormal kinase levels was performed in the blood of patients. Glycogen synthase kinase 3 (GSK 3), protein kinase R (PKR), mamalian target of rapamycin (mTOR), dual specificity tyrosine-phosphorylation-regulated kinase 1A (DIRK1A), c-Jun N-terminal kinase (JNK), protein 70 kD ribosomal protein S6 kinase (P70S6K), ERK2 and other kinase concentrations were evaluated and abnormal levels were found in many studies. For example, GSK3 levels are increased in MCI and AD patients. PKR levels are also augmented in peripheral blood mononuclear cells (PBMC) of AD patients. In the future, the assessment of several blood kinase levels in large cohorts of patients will be needed to confirm the usefulness of this test at an early phase of the disease.

Neurotrophin Expression in Lymphocytes: a Powerful Indicator of Degeneration in Parkinson's Disease, Amyotrophic Lateral Sclerosis and Ataxia

Deregulated neurotrophin is an etiological factor in the pathology of neurodegenerative diseases (ND) that are clinically different entities but characterised by similar limb dysfunction. Earlier validation of peripheral biomarkers can provide significant translational benefit to ND patients. We analysed brain-derived neurotrophic factor (BDNF)-tropomyosin possessing tyrosine-related kinase (Trk B) and its key downstream proteins which are implicated in ND such as Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS) and ataxia. Blood from ND patients with PD, ALS and Ataxia with movement dysfunctions were obtained to analyse mRNA and protein expressions of the above mentioned factors in lymphocytes. The mRNA and protein expression of BDNF-Trk B and its key downstream molecules showed a significant variation when compared to control and among NDs. The study intends to show that on identifying the variation of these key molecules in the blood samples of patients with ND can serve as early diagnostic candidates. Thus by intervening, the neurotrophins and their pathways can help in early diagnosis and optimising levels of diagnostic certainty.

Down-regulation of anti-apoptotic genes in tumor cell lines is facilitated by suppression of OCT4B1

PURPOSE

The OCT4B1 as a variant of OCT4 is expressed in both cancer cells and tissues. The anti-apoptotic property of this variant aid cancer cells to escape from apoptosis. Therefore, the aim of the present study was to determine the effects of OCT4B1 suppression on regulation of 25 genes involved in anti-apoptotic pathway in tumor cell lines.

MATERIAL AND METHODS

AGS (gastric adenocarcinoma), 5637 (bladder tumor) and U-87MG (brain tumor) cells were transfected with specific OCT4B1 siRNA and a scramble siRNA by siRNA silencing gene technology, using Lipofectamine 2000 commercial kit. The real-time PCR technique was employed to examine and calculate fold changes of evaluated genes using the 2^-ΔΔCT formula.

RESULTS

Present results demonstrated that 22 (88%) of interested genes were similarly down-regulated in all three examined cell lines. Our results also indicated that three genes (CASP2, IGF1R,TNF) were up-regulated. The CFLAR gene was down-regulated in AGS, while it was inversely up-regulated in 5637 and U87MG cells.

CONCLUSIONS

It may possibly be concluded that suppression of OCT4B1 can lead to apoptosis in tumor cell lines and this is at least facilitated via down-regulation of examined anti-apoptotic genes. Accordingly, suppression of OCT4B1 may probably be considered as useful tool in cancer therapy and research.

Protective effects of isolecanoric acid on neurodegenerative in vitro models

Parkinson's disease (PD) and Amyotrophic lateral sclerosis (ALS), are neurodegenerative disorders characterized by loss of dopaminergic or motor neurons, respectively. Although understanding of the PD and ALS pathogenesis remains incomplete, increasing evidence from human and animal studies has suggested that aberrant GSK3β, oxidative stress and mitochondrial damage are involved in their pathogenesis. Using two different molecular models, treatment with L-BMAA for ALS and rotenone for PD the effect of isolecanoric acid, a natural product isolated from a fungal culture, was evaluated. Pre-treatment with this molecule caused inhibition of GSK3β and CK1, and a decrease in oxidative stress, mitochondrial damage, apoptosis and cell death. Taken together, these results indicated that isolecanoric acid might have a protective effect against the development of these neurodegenerative disorders.

Ambroxol-induced rescue of defective glucocerebrosidase is associated with increased LIMP-2 and saposin C levels in GBA1 mutant Parkinson's disease cells

Heterozygous mutations in GBA1 gene, encoding for lysosomal enzyme glucocerebrosidase (GCase), are a major risk factor for sporadic Parkinson's disease (PD). Defective GCase has been reported in fibroblasts of GBA1-mutant PD patients and pharmacological chaperone ambroxol has been shown to correct such defect. To further explore this issue, we investigated GCase and elements supporting GCase function and trafficking in fibroblasts from sporadic PD patients--with or without heterozygous GBA1 mutations--and healthy subjects, in basal conditions and following in vitro exposure to ambroxol. We assessed protein levels of GCase, lysosomal integral membrane protein-2 (LIMP-2), which mediates GCase trafficking to lysosomes, GCase endogenous activator saposin (Sap) C and parkin, which is involved in degradation of defective GCase. We also measured activities of GCase and cathepsin D, which cleaves Sap C from precursor prosaposin. GCase activity was reduced in fibroblasts from GBA1-mutant patients and ambroxol corrected this defect. Ambroxol increased cathepsin D activity, GCase and Sap C protein levels in all groups, while LIMP-2 levels were increased only in GBA1-mutant PD fibroblasts. Parkin levels were slightly increased only in the PD group without GBA1 mutations and were not significantly modified by ambroxol. Our study confirms that GCase activity is deficient in fibroblasts of GBA1-mutant PD patients and that ambroxol corrects this defect. The drug increased Sap C and LIMP-2 protein levels, without interfering with parkin. These results confirm that chemical chaperone ambroxol modulates lysosomal markers, further highlighting targets that may be exploited for innovative PD therapeutic strategies.

Biomarkers of Alzheimer's disease risk in peripheral tissues; focus on buccal cells

Alzheimer's disease (AD) is a progressive degenerative disorder of the brain and is the most common form of dementia. To-date no simple, inexpensive and minimally invasive procedure is available to confirm with certainty the early diagnosis of AD prior to the manifestations of symptoms characteristic of the disease. Therefore, if population screening of individuals is to be performed, more suitable, easily accessible tissues would need to be used for a diagnostic test that would identify those who exhibit cellular pathology indicative of mild cognitive impairment (MCI) and AD risk so that they can be prioritized for primary prevention. This need for minimally invasive tests could be achieved by targeting surrogate tissues, since it is now well recognized that AD is not only a disorder restricted to pathology and biomarkers within the brain. Human buccal cells for instance are accessible in a minimally invasive manner, and exhibit cytological and nuclear morphologies that may be indicative of accelerated ageing or neurodegenerative disorders such as AD. However, to our knowledge there is no review available in the literature covering the biology of buccal cells and their applications in AD biomarker research. Therefore, the aim of this review is to summarize some of the main findings of biomarkers reported for AD in peripheral tissues, with a further focus on the rationale for the use of the buccal mucosa (BM) for biomarkers of AD and the evidence to date of changes exhibited in buccal cells with AD.

Cognitive disorders and tau-protein expression among retired aluminum smelting workers

OBJECTIVES

To analyze cognitive functions and tau-protein expression in peripheral blood lymphocytes of retired aluminum (Al)-exposed workers.

METHODS

A total of 66 retired Al potroom workers and 70 unexposed controls were investigated. The cognitive functions were assessed with the Mini-Mental State Examination. The tau-protein expression in peripheral blood lymphocyte was analyzed with Western blot.

RESULTS

The cognitive functions of the exposed group were significantly decreased. Twelve mild cognitive impairment cases in the exposed group and four mild cognitive impairment cases in the control group were diagnosed. Significantly higher p-tau181 and p-tau231 levels were detected in the Al-exposed workers than in the control group.

CONCLUSIONS

The study suggests that long-term exposure to Al may cause cognitive disorders and that p-tau181 and p-tau231 might be useful indicators for monitoring cognitive decline in Al-exposed workers.

The protease Omi regulates mitochondrial biogenesis through the GSK3β/PGC-1α pathway

Loss of the mitochondrial protease activity of Omi causes mitochondrial dysfunction, neurodegeneration with parkinsonian features and premature death in mnd2 (motor neuron degeneration 2) mice. However, the detailed mechanisms underlying this pathology remain largely unknown. Here, we report that Omi participates in the process of mitochondrial biogenesis, which has been linked to several neurodegenerative diseases. The mitochondrial biogenesis is deficit in mnd2 mice, evidenced by severe decreases of mitochondrial components, mitochondrial DNA and mitochondrial density. Omi cleaves glycogen synthase kinase 3β (GSK3β), a kinase promoting PPARγ coactivator-1α (PGC-1α) degradation, to regulate PGC-1α, a factor important for the mitochondrial biogenesis. In mnd2 mice, GSK3β abundance is increased and PGC-1α abundance is decreased significantly. Inhibition of GSK3β by SB216763 or overexpression of PGC-1α can restore mitochondrial biogenesis in mnd2 mice or Omi-knockdown N2a cells. Furthermore, there is a significant improvement of the movement ability of mnd2 mice after SB216763 treatment. Thus, our study identified Omi as a novel regulator of mitochondrial biogenesis, involving in Omi protease-deficient-induced neurodegeneration.

Vaccination strategies for Parkinson disease: induction of a swift attack or raising tolerance?

Parkinson disease is the second most common neurodegenerative disease in the world, but there is currently no available cure for it. Current treatments only alleviate some of the symptoms for a few years, but they become ineffective in the long run and do not stop the disease. Therefore it is of outmost importance to develop therapeutic strategies that can prevent, stop, or cure Parkinson disease. A very promising target for these therapies is the peripheral immune system due to its probable involvement in the disease and its potential as a tool to modulate neuroinflammation. But for such strategies to be successful, we need to understand the particular state of the peripheral immune system during Parkinson disease in order to avoid its weaknesses. In this review we examine the available data regarding how dopamine regulates the peripheral immune system and how this regulation is affected in Parkinson disease; the specific cytokine profiles observed during disease progression and the alterations documented to date in patients' peripheral blood mononuclear cells. We also review the different strategies used in Parkinson disease animal models to modulate the adaptive immune response to salvage dopaminergic neurons from cell death. After analyzing the evidence, we hypothesize the need to prime the immune system to restore natural tolerance against α-synuclein in Parkinson disease, including at the same time B and T cells, so that T cells can reprogram microglia activation to a beneficial pattern and B cell/IgG can help neurons cope with the pathological forms of α-synuclein.

Peripheral expression of MAPK pathways in Alzheimer's and Parkinson's diseases

Alteration of mitogen-activated protein kinase pathways may cause aberrant protein phosphorylation and enhanced apoptosis in Alzheimer's disease (AD) and Parkinson's disease (PD). Increased susceptibility of lymphocytes to apoptosis has been reported in AD. To our knowledge this is the first study to investigate the expression and phosphorylation status of p38 mitogen-activated protein kinase (p38MAPK) and c-Jun N-terminal kinase (JNK) in peripheral blood lymphocytes of 20 AD and 20 PD patients and 20 healthy controls using western blot analysis. Compared with controls, no significant difference of total p38MAPK or JNK levels were observed in AD and PD patients, whereas phosphorylated p38MAPK and phosphorylated JNK levels were significantly increased in the AD and PD groups (p<0.001). However, the increased levels of the two phosphorylated kinases in AD versus PD patients presented no significant difference. Interestingly, phosphorylated p38MAPK and phosphorylated JNK levels were positively correlated with disease duration (r=0.602, p=0.005 and r=0.561, p=0.010, respectively) and negatively correlated with the Mini Mental State Examination score (r=-0.664, p=0.001 and r=-0.578, p=0.008, respectively) in AD patients. No correlations between protein levels and clinical variables were found in PD patients. Investigation of peripheral changes in the expression of p38MAPK and JNK may lead to the development of innovative biomarkers of neurodegenerative diseases, particularly for AD.

Altered intracellular localization of SOD1 in leukocytes from patients with sporadic amyotrophic lateral sclerosis

Several lines of evidence support the hypothesis of a toxic role played by wild type SOD1 (WT-SOD1) in the pathogenesis of sporadic amyotrophic lateral sclerosis (SALS). In this study we investigated both distribution and expression profile of WT-SOD1 in leukocytes from 19 SALS patients and 17 healthy individuals. Immunofluorescence experiments by confocal microscopy showed that SOD1 accumulates in the nuclear compartment in a group of SALS subjects. These results were also confirmed by western blot carried out on soluble nuclear and cytoplasmic fractions, with increased nuclear SOD1 level (p<0.05). In addition, we observed the presence of cytoplasmic SOD1 aggregates in agreement with an increased amount of the protein recovered by the insoluble fraction. A further confirmation of the overall increased level of SOD1 has been obtained from single cells analysis using flow cytometry as cells from SALS patients showed an higher SOD1 protein content (p<0.05). These findings add further evidence to the hypothesis of an altered WT-SOD1 expression profile in peripheral blood mononuclear cells (PBMCs) from patients with ALS suggesting that WT-SOD1 species with different degrees of solubility could be involved in the pathogenesis of the disease.

Single or combined treatment with L-DOPA and quinpirole differentially modulate expression and phosphorylation of key regulatory kinases in neuroblastoma cells

In the past decades, the clinical use of dopamine agonists has expanded from adjunct therapy in patients with a deteriorating response to L-3,4-dihydroxyphenylalanine (L-DOPA) to monotherapy for the treatment of early PD. Dopamine agonists provide their antiparkinsonian benefit through stimulation of brain postsynaptic type 2 dopamine receptors that exert their effect through classical cAMP-dependent mechanisms, as well as cAMP-independent cellular signaling cascades, including the Akt/glycogen synthase kinase 3 (GSK3) pathway. Alterations of Akt/GSK3 have been observed and may contribute to the neurodegenerative processes and the development of L-DOPA-induced dyskinesia. The effects L-DOPA and quinpirole, a dopamine agonist, on the two key regulatory kinases, Akt and GSK3, were evaluated in neuroblastoma cell line. L-DOPA and dopamine agonist dose-dependently and differentially modulated Akt and GSK3 expression and phosphorylation when added alone or combined. The combined treatment inverted or potentiated the modulatory properties of the single compound. The drug- and concentration-dependent balance of dopamine receptor stimulation over auto-oxidation may distinctively modulate GSK3 isoforms and Akt. Our results indicate that particular attention must be given to drug concentration and combination when multiple therapies are applied for the clinical treatment of PD patients.

The peripheral messenger RNA expression of glycogen synthase kinase-3β genes in Alzheimer's disease patients: a preliminary study

OBJECTIVE

To explore the peripheral leucocytic messenger RNA (mRNA) expression of glycogen synthase kinase-3β (GSK-3β) gene in Alzheimer's disease (AD) patients.

METHODS

Using TaqMan relative quantitative real-time polymerase chain reaction, we analyzed leucocytic gene expression of GSK-3β in 48 AD patients and 49 healthy controls. Clinical data of AD patients were also collected.

RESULTS

The mRNA expression level of the GSK-3β gene was significantly higher in the AD group (3.13±0.62) than in the normal group (2.77±0.77). Correlational analyses showed that the mRNA expression level of GSK-3β gene in AD patients was associated with the age of onset (P=0.047), age (P=0.055), and Behavioral Pathology in Alzheimer's Disease Rating Scale total score (P=0.062) and subscores: aggressiveness score (P=0.073) and anxieties and phobias score (P=0.067). Through multivariate regression model, older age, higher anxieties and phobias score and aggressiveness score were associated with higher mRNA expression level of GSK-3β gene.

CONCLUSION

In AD patients, the mRNA expression level of the GSK-3β gene is increased and may be related to age and behavioural pathology in AD.

Amyloid-β toxicity and tau hyperphosphorylation are linked via RCAN1 in Alzheimer's disease

Amyloid-β peptide (Aβ) toxicity and tau hyperphosphorylation are hallmarks of Alzheimer's disease (AD). How their molecular relationships may affect the etiology, progression, and severity of the disease, however, has not been elucidated. We now report that incubation of fetal rat cortical neurons with Aβ upregulates expression of the Regulator of Calcineurin gene RCAN1, and this is mediated by Aβ-induced oxidative stress. Calcineurin (PPP3CA) is a serine-threonine phosphatase that dephosphorylates tau. RCAN1 proteins inhibit this phosphatase activity of calcineurin. Increased expression of RCAN1 also causes upregulation of glycogen synthase kinase-3β (GSK3β), a tau kinase. Thus, increased RCAN1 expression might be expected to decrease phospho-tau dephosphorylation (via calcineurin inhibition) and increase tau phosphorylation (via increased GSK3β activity). Indeed, we find that incubation of primary cortical neurons with Aβ results in increased phosphorylation of tau, unless RCAN1 gene expression is silenced, or antioxidants are added. Thus we propose a mechanism to link Aβ toxicity and tau hyperphosphorylation in AD: In our hypothesis, Aβ causes mitochondrial oxidative stress and increases production of reactive oxygen species, which result in an upregulation of RCAN1 gene expression. RCAN1 proteins then both inhibit calcineurin and induce expression of GSK3β. Both mechanisms shift tau to a hyperphosphorylated state. We also find that lymphocytes from persons whose ApoE genotype is ε4/ε4 (with high risk of developing AD) show higher levels of RCAN1 and phospho-tau than those carrying the ApoE ε3/ε3 or ε3/ε4 genotypes. Thus upregulation of RCAN1 may be a valuable biomarker for AD risk.

Past, present and future of A(2A) adenosine receptor antagonists in the therapy of Parkinson's disease

Several selective antagonists for adenosine A(2A) receptors (A(2A)R) are currently under evaluation in clinical trials (phases I to III) to treat Parkinson's disease, and they will probably soon reach the market. The usefulness of these antagonists has been deduced from studies demonstrating functional interactions between dopamine D₂ and adenosine A(2A) receptors in the basal ganglia. At present it is believed that A(2A)R antagonists can be used in combination with the dopamine precursor L-DOPA to minimize the motor symptoms of Parkinson's patients. However, a considerable body of data indicates that in addition to ameliorating motor symptoms, adenosine A(2A)R antagonists may also prevent neurodegeneration. Despite these promising indications, one further issue must be considered in order to develop fully optimized antiparkinsonian drug therapy, namely the existence of (hetero)dimers/oligomers of G protein-coupled receptors, a topic that is currently the focus of intense debate within the scientific community. Dopamine D₂ receptors (D₂Rs) expressed in the striatum are known to form heteromers with A(2A) adenosine receptors. Thus, the development of heteromer-specific A(2A) receptor antagonists represents a promising strategy for the identification of more selective and safer drugs.

GSK-3 in Neurodegenerative Diseases

Glycogen synthase kinase-3 (GSK-3) regulates multiple cellular processes, and its dysregulation is implicated in the pathogenesis of diverse diseases. In this paper we will focus on the dysfunction of GSK-3 in Alzheimer's disease and Parkinson's disease. Specifically, GSK-3 is known to interact with tau, β-amyloid (Aβ), and α-synuclein, and as such may be crucially involved in both diseases. Aβ production, for example, is regulated by GSK-3, and its toxicity is mediated by GSK-induced tau phosphorylation and degeneration. α-synuclein is a substrate for GSK-3 and GSK-3 inhibition protects against Parkinsonian toxins. Lithium, a GSK-3 inhibitor, has also been shown to affect tau, Aβ, and α-synuclein in cell culture, and transgenic animal models. Thus, understanding the role of GSK-3 in neurodegenerative diseases will enhance our understanding of the basic mechanisms underlying the pathogenesis of these disorders and also facilitate the identification of new therapeutic avenues.