Modulation of disease risk according to a cathepsin D / apolipoprotein E genotype in Parkinson's disease

The genetic association between apolipoprotein E gene polymorphism and Parkinson disease: A meta-Analysis of 47 studies

OBJECTIVE

Although the relationship between apolipoprotein E (ApoE) gene polymorphisms and the risk of Parkinson disease (PD) has been established, the results were inconsistent and inconclusive.

METHODS

A comprehensive search examining the association between APOE polymorphisms and PD through PubMed, Embase, Chinese National Knowledge Infrastructure (CNKI), and Cochrane Library databases was performed without published year limited.

RESULTS

A total of 47 studies with 7533 cases and 14442 controls were included in present study. The results showed statistically significant association between risk factor ApoE ε4 allele and PD in Asian population (P = .003, odds ratio, OR [95% confidence interval, CI] = 1.43 [1.13,1.80]). Genotype ε2ε4 have significantly associated with PD in Asian population (P = .004, OR [95% CI] = 4.43 [1.62,12.10]). Genotype ε3ε4 was significantly associated with PD in Latin-American population (P = .01, OR [95% CI] = 1.44 [1.08,1.91]). In addition, the frequency of the genotype ε3ε4 is lower in PD group than that in the control group in Caucasian population, and the difference of genotype ε3ε4 is also statistically significant (P = .006, OR [95% CI] = 0.86 [0.77,0.96]). Although significant heterogeneity was observed among all studies, the results were shown to be stabilized by sensitive analysis. No publish bias was observed.

CONCLUSIONS

This meta-analysis suggests that the APOE ε4, but no ε2, might be a risk factor for PD in Asian population. Furthermore, the genotype ε2ε4 may be a susceptible factor for PD in Asian population, and the genotype ε3ε4 may be a susceptible factor for PD in both Caucasian and Latin-American populations.

Relationship between Apolipoprotein Superfamily and Parkinson's Disease

Objective:

Parkinson's disease (PD) is featured with motor disorder and nonmotor manifestations including psychological symptoms, autonomic nervous system dysfunction, and paresthesia, which results in great inconvenience to the patients’ life. The apolipoprotein (Apo) superfamily, as a group of potentially modifiable biomarkers in clinical practice, is of increasing significance in the diagnosis, evaluation, and prognosis of PD. The present review summarized the current understanding and emerging findings of the relationship between Apo superfamily and PD.

Data Sources:

All literatures were identified by systematically searching PubMed, Embase, and Cochrane electronic databases with terms “Parkinson disease,” “apolipoprotein,” and their synonyms until May 2017.

Study Selection:

We have thoroughly examined titles and abstracts of all the literatures that met our search strategy and the full text if the research is identified or not so definite. Reference lists of retrieved articles were also scrutinized for additional relevant studies.

Results:

The levels of plasma ApoA1 are inversely correlated with the risk of PD and the lower levels of ApoA1 trend toward association with poorer motor performance. Higher ApoD expression in neurons represents more puissant protection against PD, which is critical in delaying the neurodegeneration process of PD. It is suggested that APOE alleles are related to development and progression of cognitive decline and age of PD onset, but conclusions are not completely identical, which may be attributed to different ApoE isoforms. APOJ gene expressions are upregulated in PD patients and it is possible that high ApoJ level is an indicator of PD dementia and correlates with specific phenotypic variations in PD.

Conclusions:

The Apo superfamily has been proved to be closely involved in the initiation, progression, and prognosis of PD. Apos and their genes are of great value in predicting the susceptibility of PD and hopeful to become the target of medical intervention to prevent the onset of PD or slow down the progress. Therefore, further large-scale studies are warranted to elucidate the precise mechanisms of Apos in PD.

LRRK2(I2020T) functional genetic interactors that modify eye degeneration and dopaminergic cell loss in Drosophila

Progressive degeneration of dopaminergic neurons in the substantia nigra pars compacta is the primary cause for motor symptoms observed in Parkinson's disease (PD). Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most commonly linked contributor to familial PD. LRRK2 is suggested to be involved in a wide variety of cellular processes, but deciphering its role in the pathogenesis of PD has been difficult. Modelling PD in rodents has been a persistent challenge for the field. However, the fruit fly has been exploited to recapitulate PD gene related dopaminergic cell loss. Using the GAL4-UAS system and established models of hLRRK2 induced eye degeneration in Drosophila, we conducted an unbiased suppressor/enhancer screen to uncover genetic modifiers of LRRK2. We have identified 36 candidate interactors that modify LRRK2 induced toxicity in the Drosophila eye. Importantly, we determined that a subset of these interactors also modified hLRRK2(I2020T) induced dopaminergic neuronal loss in the fly brain and uncovered 16 candidates that modify dopaminergic cell loss. Our results suggest LRRK2 may be involved in a wide variety of cellular processes and the results from this screen provide an important genetic resource for further evaluation of LRRK2 function.

SMA-MAP: a plasma protein panel for spinal muscular atrophy

Objectives

Spinal Muscular Atrophy (SMA) presents challenges in (i) monitoring disease activity and predicting progression, (ii) designing trials that allow rapid assessment of candidate therapies, and (iii) understanding molecular causes and consequences of the disease. Validated biomarkers of SMA motor and non-motor function would offer utility in addressing these challenges. Our objectives were (i) to discover additional markers from the Biomarkers for SMA (BforSMA) study using an immunoassay platform, and (ii) to validate the putative biomarkers in an independent cohort of SMA patients collected from a multi-site natural history study (NHS).

Methods

BforSMA study plasma samples (N = 129) were analyzed by immunoassay to identify new analytes correlating to SMA motor function. These immunoassays included the strongest candidate biomarkers identified previously by chromatography. We selected 35 biomarkers to validate in an independent cohort SMA type 1, 2, and 3 samples (N = 158) from an SMA NHS. The putative biomarkers were tested for association to multiple motor scales and to pulmonary function, neurophysiology, strength, and quality of life measures. We implemented a Tobit model to predict SMA motor function scores.

Results

12 of the 35 putative SMA biomarkers were significantly associated (p<0.05) with motor function, with a 13^th analyte being nearly significant. Several other analytes associated with non-motor SMA outcome measures. From these 35 biomarkers, 27 analytes were selected for inclusion in a commercial panel (SMA-MAP) for association with motor and other functional measures.

Conclusions

Discovery and validation using independent cohorts yielded a set of SMA biomarkers significantly associated with motor function and other measures of SMA disease activity. A commercial SMA-MAP biomarker panel was generated for further testing in other SMA collections and interventional trials. Future work includes evaluating the panel in other neuromuscular diseases, for pharmacodynamic responsiveness to experimental SMA therapies, and for predicting functional changes over time in SMA patients.

Cerebellar dysfunction in a family harboring the PSEN1 mutation co-segregating with a cathepsin D variant p.A58V

Presenile dementia may be caused by a variety of different genetic conditions such as familial Alzheimer's disease, prion disease as well as several hereditary metabolic disorders including adult onset neuronal ceroid lipofuscinosis. We report a multigenerational family with autosomal dominant presenile dementia harboring a cerebellar phenotype. Longitudinal clinical work-up in affected family members revealed ataxia accompanied by progressive cognitive decline, rapid loss of global cognition, memory, visuospatial and frontal-executive functions accompanied by progressive motor deterioration and early death. Linkage analysis and exome sequencing identified the p.S170F mutation of Presenilin 1 in all affected individuals, which is known to be associated with very early onset Alzheimer's disease. Additional search for potentially modifying variants revealed in all affected individuals of the third generation a paternally inherited variant p.A58V (rs17571) of Cathepsin D which is considered an independent risk factor for Alzheimer's disease. Involvement of cerebellar and brainstem structures leading to functional decortication in addition to rapid progressive presenile dementia in this PSEN1 family may therefore indicate an epistatic effect of the p.A58V Cathepsin D variant on the deleterious course of this disease.

Clinicopathological significance of cathepsin D expression in non-small cell lung cancer is conditional on apoptosis-associated protein phenotype: an immunohistochemistry study

Cathepsin D is a well-known peptidase which belongs to the family of aspartic peptidases. It has been found to be overexpressed in many malignant tumors and associated with cancer metastasis and clinical outcome. However, its function in cancers remains controversial. Recently, increasing evidence shows that cathepsin D may play important roles in cell apoptosis. In the current study, we examined the expression of cathepsin D and a group of apoptosis-associated proteins including bcl-2, caspase 3, fas, fasL, p53, and survivin in nonsmall cell lung cancer (NSCLC) tissues to investigate the possible association between cathepsin D and these apoptosis-associated proteins and the clinicopathological features using immunohistochemistry. Cathepsin D expression was detected in cancer tissues including cancer cells (positive rate 64.5%(49/76)) and stromal parts including leukocytes, fibroblasts, capillary endothelial cells, and the matrix. No significant difference was found between the expression of cathepsin D in cancer cells and the corresponding non-tumor portions including bronchial epithelia and submucosal glands (positive rate 53.3% (8/15)) (p>0.05). Immunofluorescence study on formalin-fixed, paraffin-embedded specimens confirmed the cytoplasmic expression of cathepsin D in cancer cells and non-tumor portions. Western blot study detected both mature and immature forms of cathepsin D in lung and NSCLC tissues, while the expression level of neither form showed a significant difference between these tissues (p>0.05). Positive association was found between cathepsin D expression and fas status (p<0.01) but not with the other apoptosis-associated proteins (p>0.05) in cancer cells. Cathepsin D expression alone was not associated with any of the clinicopathological features (p>0.05), while multiplemarker analysis revealed that two immunostaining phenotypes based on the expression of cathepsin D and one of the apoptosis-associated proteins, namely, cathepsin D+/caspase 3- and cathepsin D+/p53+ showed clinicopathological significance. The cathepsin D+/caspase 3- group was associated with advanced tumor node metastasis stages (III and IV) (p<0.05), while the cathepsin D+/p53+ group was associated with lymph node metastasis (p<0.05). The present findings indicate that the expression of cathepsin D in non-small cell lung cancer may have possible contributions to cancer development which is conditional on apoptosis-associated protein phenotype.

Association between apolipoprotein E genotypes and Parkinson's disease

Previous studies on the association between apolipoprotein E (APOE) alleles and Parkinson's disease (PD) have shown contradictory results. A recent study showed that APOE is involved in a molecular pathway of α-synuclein-induced neurodegeneration. We therefore conducted the first Thai study on APOE genotypes in patients with PD. We analysed the frequencies of APOE genotypes in our case-control study of 155 patients with sporadic PD and 158 control participants. We identified a higher frequency of the APOE-ε2 allele among patients with PD than among controls (odds ratio=2.309, 95% confidence interval=1.111-4.799). Genetic association is a powerful tool for detecting disease susceptibility alleles, but there are many pitfalls to consider before claiming any association. The discrepancy among the results of the genetic association studies of APOE genotypes as a risk of susceptibility to PD emphasises that this association merits clarification by the study of a single large homogeneous population.

Genetic polymorphism in exon 2 of cathepsin D is not associated with vascular dementia

BACKGROUND

Cathepsin D, the most abundant lysosomal and endosomal aspartyl protease, shows beta and gamma secretase activity in vitro by cleaving the amyloid precursor protein (APP) into amyloid beta protein (Aβ). Polymorphism at position 224, C224T, on exon 2 of cathepsin D gene (CTSD) has been associated with an increased risk for Alzheimer's disease (AD) by some investigators, but there have been contrary findings by others. However, an association between CTSD polymorphism and vascular dementia (VaD) has not been reported thus far.

OBJECTIVE

To investigate whether a polymorphism at CTSD C224T is associated with VaD in the Korean population.

METHODS

We compared the genotype and allele frequencies at this polymorphism site in clinically assessed 162 VaD patients with those in 197 healthy Koreans.

RESULTS AND CONCLUSION

The major genotype frequency at CTSD C224T in normal controls was higher in the Asian population than in various European populations. Our study does not show a significant difference in genotype (P=0.3071) and allele (P=0.2291) frequencies of CTSD C224T between VaD and normal controls. This was the first genetic association study of CTSD in a VaD population.

Dendritic cells in multiple sclerosis lesions: maturation stage, myelin uptake, and interaction with proliferating T cells

In multiple sclerosis (MS), dendritic cells (DCs) recruited to the central nervous system (CNS) are thought to be involved in the regulation of autoimmune responses directed against myelin antigens. To better understand the role of DCs in CNS inflammation, we performed a detailed immunohistochemical analysis of DC maturation markers and of DC relationship to CNS-infiltrating T cells in autopsy brain tissue of patients with MS. We also investigated the presence of DCs containing myelin debris in MS lesions. Myeloid DC subsets were identified using the following markers: CD1a for immature DCs; DC-SIGN for immature and mature DCs; and fascin, CD83, DC-LAMP, and CCR7 for mature DCs. The most common finding was the presence of cells expressing DC-SIGN and containing myelin components in the perivascular cuffs of early active and chronic (both active and inactive) MS lesions. Perivascular CD1a DCs were detected in active lesions in only one of 10 patients with MS who were examined. Although less numerous than DC-SIGN DCs, cells expressing mature DC markers were consistently detected in the inflamed meninges and perivascular cuffs of most active lesions examined. CCR7 immunostaining was predominantly confined to activated microglia at the lesion edges. Some perivascular DC-SIGN cells were found in close proximity to or contacting rare proliferating lymphocytes, most of which expressed the DC-SIGN ligand ICAM-3 and CD8. These data suggest that DCs recruited and maturing in MS lesions, where self-antigens are made available by continuous myelin destruction, may contribute to the local activation and expansion of presumably pathogenic T cells.

Apolipoprotein E4 genotype is not associated with short-term cognition deficits during alcohol withdrawal

Aim of this prospective study was to investigate a possible association between the apolipoprotein E4 (ApoE4) genotype and clinically well-known cognition deficits during alcohol withdrawal. We examined 172 patients with alcohol dependence (137 men, 35 women) during withdrawal treatment. The ApoE genotype was determined in all patients using polymerase chain reaction. Cognitive function was assessed applying the c.I.-Test on day 0 (admission) and on day 7 of withdrawal treatment. Using Pearson's chi2 test we found no significant association between the ApoE4 genotype and cognition deficits for both dates (day 0: p=.463; day 7: p=.760). Moreover, multivariate logistic regression analyses revealed no significant association between presence of the ApoE4 allele and cognitive dysfunction. Even though ApoE4 plays an important role in alcoholism-related brain atrophy and cognition deficits in demented as well as in nondemented healthy elderly people, this study provides no evidence for an association with short-term cognition deficits during alcohol withdrawal.

Subnanoliter enzymatic assays on microarrays

Many areas of research today are based on enzymatic assays most of which are still performed as enzyme-linked immunosorbent assays in microtiter plates. The demand for highly parallel screening of thousands of samples eventually led to a miniaturization and automation of these assays. However, the final transfer of enzymatic assays from a microtiter-based technology to microarrays has proven to be difficult for various reasons, such as the inability to maintain unbound reaction products on the spot of reaction or the missing capability of multiplexing. Here, we have conducted multiplex enzymatic assays in subnanoliter volumes on a single microarray using the multiple spotting technology. We were able to measure enzymatic activity with a sensitivity down to 35 enzyme molecules, applying only conventional flat microarray surfaces and standard microarray hardware. We have performed assays of inhibition and applied this format for the detection of prognostic markers, such as cathepsin D. The new approach allows the rapid and multiplex screening of thousands of samples on a single microarray with applications in drug screening, metagenomics, and high-throughput enzyme assays.