LRRK2 expression linked to dopamine-innervated areas

OBJECTIVE

Leucine-rich repeat kinase 2 (LRRK2) has been linked to Parkinson's disease. Our study explores the expression of LRRK2 in human and rodent brain tissue.

METHODS

We analyzed LRRK2 gene activity at the cellular level using in situ hybridization.

RESULTS

We found a high and strikingly specific expression of LRRK2 mRNA in rodent striatum and parts of cortex and no signals in dopamine neurons. In human tissue, LRRK2 mRNA was found in the corresponding brain areas caudatus and putamen at lower levels and dopamine neurons were also devoid of LRRK2 mRNA. Expression levels in striatal tissue did not differ between Parkinson's disease patients and control subjects.

INTERPRETATION

Unlike all other genes so far linked to Parkinson's disease, our results demonstrate that LRRK2 expression is particularly high in brain dopaminoceptive areas.

Tissue- and species-specific expression patterns of class I, III, and IV Adh and Aldh1 mRNAs in rodent embryos

Alcohol and aldehyde dehydrogenases (ADHs and ALDHs) may be of interest in the pathology of Parkinson's disease (PD) because of their role in protection against toxins and in retinoid metabolism, which is required for growth and development of the mesencephalic dopamine system. In the present study, the spatial and temporal expression patterns of Adh 1, Adh 3, Adh 4, and Aldh 1 mRNAs in embryonic C57BL/6 mice (E 9.5-E19.5) and Sprague-Dawley rats (E12.5-P0) have been investigated by using radioactive oligonucleotide in situ hybridization. High expression of Aldh 1 mRNA was found in the developing mesencephalic dopamine neurons of both mice and rats. Expression of Adh 1 and Adh 4 mRNAs was observed in adrenal cortex and olfactory epithelium in mice. Additionally, Adh 1 was expressed in epidermis, liver, conjunctival, and intestinal epithelium. In rat embryos, expression was less extensive, with Adh 1 mRNA being found in liver and intestines. Adh 3 expression was ubiquitous in both mouse and rat embryos, suggesting a housekeeping function of the gene. Consistent with previous studies in adult rats and mice, our data suggest that Adh 3 is the only ADH class present in rodent brain. Adh and Aldh gene activity in mouse and rat embryos indicate the possible involvement of the respective enzymes in retinoid metabolism and participation in defense against toxic insults, including those that may be involved in the pathogenesis of PD.

Investigation of genes coding for inflammatory components in Parkinson's disease

Several findings obtained recently indicate that inflammation may contribute to the pathogenesis in Parkinson's disease (PD). Genetic variants of genes coding for components involved in immune reactions in the brain might therefore influence the risk of developing PD or the age of disease onset. Five single nucleotide polymorphisms (SNPs) in the genes coding for interferon-gamma (IFN-gamma; T874A in intron 1), interferon-gamma receptor 2 (IFN-gamma R2; Gln64Arg), interleukin-10 (IL-10; G1082A in the promoter region), platelet-activating factor acetylhydrolase (PAF-AH; Val379Ala), and intercellular adhesion molecule 1 (ICAM-1; Lys469Glu) were genotyped, using pyrosequencing, in 265 patients with PD and 308 controls. None of the investigated SNPs was found to be associated with PD; however, the G1082A polymorphism in the IL-10 gene promoter was found to be related to the age of disease onset. Linear regression showed a significantly earlier onset with more A-alleles (P = 0.0095; after Bonferroni correction, P = 0.048), resulting in a 5-year delayed age of onset of the disease for individuals having two G-alleles compared with individuals having two A-alleles. The results indicate that the IL-10 G1082A SNP could possibly be related to the age of onset of PD.

A rare truncating mutation in ADH1C (G78Stop) shows significant association with Parkinson disease in a large international sample

BACKGROUND

Alcohol dehydrogenases (ADHs) may be involved in the pathogenesis of neurodegenerative disorders because of their multiple roles in detoxification pathways and retinoic acid synthesis. In a previous study, significant association of an ADH class IV allele with Parkinson disease (PD) was found in a Swedish sample.

PATIENTS

The previously associated single-nucleotide polymorphism plus 12 further polymorphisms in the ADH cluster on human chromosome 4q23 were screened for association in an extension of the original sample that now included 123 Swedish PD patients and 127 geographically matched control subjects. A rare nonsense single-nucleotide polymorphism in ADH1C (G78stop, rs283413) was identified in 3 of these patients but in no controls. To obtain sufficient power to detect a possible association of this rare variant with disease, we screened a large international sample of 1076 PD patients of European ancestry and 940 matched controls.

RESULTS

The previously identified association with an ADH class IV allele remained significant (P<.02) in the extended Swedish study. Furthermore, in the international collaboration, the G78stop mutation in ADH1C was found in 22 (2.0%) of the PD patients but only in 6 controls (0.6%). This association was statistically significant (chi(2)(1) = 7.5; 2-sided P = .007; odds ratio, 3.25 [95% confidence interval, 1.31-8.05]). In addition, the G78stop mutation was identified in 4 (10.0%) of 40 Caucasian index cases with PD with mainly hereditary forms of the disorder.

CONCLUSION

Findings presented herein provide further evidence for mutations in genes encoding ADHs as genetic risk factors for PD.

Interaction of polymorphisms in the genes encoding interleukin-6 and estrogen receptor beta on the susceptibility to Parkinson's disease

The multifunctional cytokine interleukin-6 (IL-6) is involved in inflammatory processes in the central nervous system and increased levels of IL-6 have been found in patients with Parkinson's disease (PD). It is known that estrogen inhibits the production of IL-6, via action on estrogen receptors, thereby pointing to an important influence of estrogen on IL-6. In a previous study, we reported an association between a G/A single nucleotide polymorphism (SNP) at position 1730 in the gene coding for estrogen receptor beta (ERbeta) and age of onset of PD. To investigate the influence of a G/C SNP at position 174 in the promoter of the IL-6 gene, and the possible interaction of this SNP and the ERbeta G-1730A SNP on the risk for PD, the G-174C SNP was genotyped, by pyrosequencing, in 258 patients with PD and 308 controls. A significantly elevated frequency of the GG genotype of the IL-6 SNP was found in the patient group and this was most obvious among patients with an early age of onset (</=50 years) of PD. When the GG genotypes of the IL-6 and ERbeta SNPs were combined, the combination was much more robustly associated with PD, and especially with PD with an early age of onset, than respective GG genotype when analyzed separately. Our results indicate that the G-174C SNP in the IL-6 promoter may influence the risk for developing PD, particularly regarding early age of onset PD, and that the effect is modified by interaction of the G-1730A SNP in the ERbeta gene.

Association between the estrogen receptor beta gene and age of onset of Parkinson's disease

The purpose of this study was to investigate the potential contribution of genetic variants in the estrogen receptor beta gene to the aetiology of Parkinson's disease (PD). Several lines of evidence from human and animal studies suggest a protective role for estrogen in PD. Recently the estrogen receptor beta subtype was reported to be an important mediator of estrogen actions in the nigrostriatal dopamine system. Two single nucleotide polymorphisms at position 1730 and 1082 in the ER beta gene were genotyped, using pyrosequencing, in 260 patients with PD and 308 controls recruited from the Swedish population. Neither of the two estrogen receptor beta polymorphisms was associated with an increased risk for PD. However, the G allele of the A1730G polymorphism was more frequent in patients with an early age of onset than in patients with a late age of onset of PD (P = 0.006). Patients carrying the GG genotype had an odds ratio of 2.2 for having an early onset of PD compared to non-carriers. In conclusion, our results indicate that genetic variation in the estrogen receptor beta gene may influence the age of onset of PD.

ALDH1 mRNA: presence in human dopamine neurons and decreases in substantia nigra in Parkinson's disease and in the ventral tegmental area in schizophrenia

Dopamine (DA) neurons degenerate in Parkinson's disease and dopamine neurotransmission may be affected in psychotic states seen in schizophrenia. Understanding the regulation of enzymes involved in DA metabolism may therefore lead to new treatment strategies for these severe conditions. We investigated mRNA expression of the cytosolic aldehyde dehydrogenase (ALDH1), presumably involved in DA degradation, by in situ hybridization in DA neurons of human postmortem material. Parallel labeling for GAPDH, neuron-specific enolase, tyrosine hydroxylase, dopamine transporter, and dopamine beta-hydroxylase was used to ensure suitability of tissue specimen and to identify all dopamine neurons. ALDH1 was found to be expressed highly and specifically in DA cells of both substantia nigra (SN) and the ventral tegmental area (VTA) of controls. A marked reduction of ALDH1 expression was seen in surviving neurons of SN pars compacta but not of those in the VTA in Parkinson's disease. In patients suffering from schizophrenia we found ALDH1 expression at normal levels in DA cells of SN but at significantly reduced levels in those of the VTA. We conclude that ALDH1 is strongly and specifically expressed in human mesencephalic dopamine neurons and that low levels of ALDH1 expression correlate with DA neuron dysfunction in the two investigated human conditions.

NURR1 promoter polymorphisms: Parkinson's disease, schizophrenia, and personality traits

We have previously identified mutations in exon three in NURR1 (NR4A2) in two patients with schizophrenia (SZ) and one patient with bipolar disease with psychotic symptoms. In the present study we analyzed the promoter region of NURR1 and identified five polymorphic sites: three were found to be in strong linkage disequilibrium with a previously identified polymorphic site in the sixth intron. One polymorphism of this haplotype and the two other independent polymorphisms were investigated for their possible association with SZ and Parkinson's disease (PD) by comparing their frequencies in a Swedish material consisting of 134 subjects with SZ and 207 matched controls and 108 subjects with PD and 125 matched controls. Exon 1 was also investigated in our Parkinson and control material but no variances were found. The distributions of the two most informative polymorphisms in the promoter were investigated in an American material as well consisting of 141 subjects with SZ and 139 matched controls. Furthermore, the identified markers were screened for association with putative endophenotypes of SZ in the Swedish material. The distribution of sequence variants among the Swedish controls matched for SZ was investigated with regard to personality. No significant genotype or allelic association of the three sequence variants with SZ or PD was found. Several comparisons regarding endophenotypes or personality indicated association at the 5% confidence level, although correction for multiple testing rendered none of these findings significant. We conclude that the identified polymorphic sites in the human NURR1 are unlikely to be involved in conferring susceptibility for SZ or PD in our patient material.

Decreased ethanol preference and wheel running in Nurr1-deficient mice

Nurr1 (Nr4a2) is a transcription factor expressed in dopamine cells from early development and throughout life. Null mutants for Nurr1 lack the ventral midbrain dopamine neurons and die soon after birth. Animals with a heterozygous deletion are viable and display no apparent abnormality. We have investigated the impact of heterozygous deletion of Nurr1 on ethanol consumption in adult mice as a model for drug-induced reward and on wheel running as a model for natural reward. Interestingly, Nurr1 heterozygous mice never developed high ethanol consumption nor did they develop as much running behaviour as did the wild-type animals. Thus, Nurr1 appears to have a key role for the reinforcing properties of ethanol and running that underlies the development of excessive reward-seeking behaviours characteristic for addiction. Quantitative trait loci mapping using C57Bl/6 and DBA/2 mice describe a locus for ethanol preference on chromosome 2, wherein Nurr1 is located. We found two dinucleotide repeats in the Nurr1 promoter that were longer in mice with low preference for ethanol (DBA/2 and 129/Sv) than in mice with high preference for ethanol (C57Bl/6J and C57Bl/6NIH). These sequential data are compatible with Nurr1 as a candidate gene responsible for the quantitative trait loci for ethanol preference on mouse chromosome 2. Together, our data thus imply involvement of Nurr1 in the transition to a state of high ethanol consumption as well as in the development of a high amount of wheel running in mice.

Two NOTCH4 polymorphisms and their relation to schizophrenia susceptibility and different personality traits

BACKGROUND

Recently, linkage disequilibrium mapping of the major histocompatibility complex region on the short arm of human chromosome 6 suggested that the NOTCH4 locus is highly associated with schizophrenia.

OBJECTIVES AND METHODS

We analysed two polymorphisms in this gene in Swedish schizophrenic patients ( =74) and control subjects ( =135). The NOTCH4 variants were also analysed in schizophrenic patients with regard to subdiagnosis, age at first hospitalization, abuse/dependence of alcohol, solvents, or drugs, previous suicide attempts, extrapyramidal symptoms, treatment with anticholinergic drugs, and response to anti-psychotic drug treatment. Control subjects were scrutinized with regard to personality, another partially heritable trait suggested being of importance in schizophrenia. In addition, two intermediate endophenotypes suggested being of importance in schizophrenia, dopamine D(2) receptor density in striatum and monoamine metabolites in cerebrospinal fluid, respectively, were investigated with regard to the two NOTCH4 variants.

RESULTS

There was no significant association between the patients and the controls for the two investigated polymorphisms neither for the parameters analysed in the schizophrenia material. The NOTCH4 SNP2 variant, an A-->G substitution, was associated with the Karolinska Scales of Personality Irritability scale. The NOTCH4 (CTG)(n) variant was associated with the revised NEO personality inventory Extraversion and Activity (E4) scales. However, after correction for multiple testing, no difference remained significant. The results for the endophenotypes and the polymorphisms were non-significant.

CONCLUSIONS

The present study does not support that the investigated NOTCH4 variants have a major influence on susceptibility to schizophrenia or related neurobiological traits.

Distribution of class I, III and IV alcohol dehydrogenase mRNAs in the adult rat, mouse and human brain

The localization of different classes of alcohol dehydrogenases (ADH) in the brain is of great interest because of their role in both ethanol and retinoic acid metabolism. Conflicting data have been reported in the literature. By Northern blot and enzyme activity analyses only class III ADH has been detected in adult brain specimens, while results from riboprobe in situ hybridization indicate class I as well as class IV ADH expression in different regions of the rat brain. Here we have studied the expression patterns of three ADH classes in adult rat, mouse and human tissues using radioactive oligonucleotide in situ hybridization. Specificity of probes was tested on liver and stomach control tissue, as well as tissue from class IV ADH knock-out mice. Only class III ADH mRNA was found to be expressed in brain tissue of all three investigated species. Particularly high expression levels were found in neurons of the red nucleus in human tissue, while cortical neurons, pyramidal and granule cells of the hippocampus and dopamine neurons of substantia nigra showed moderate expression levels. Purkinje cells of cerebellum were positive for class III ADH mRNA in all species investigated, whereas granular layer neurons were positive only in rodents. The choroid plexus was highly positive for class III ADH, while no specific signal for class I or class IV ADH was detected. Our results thus support the notion that the only ADH expressed in adult mouse, rat and human brain is class III ADH.

Further evidence for an association of the paraoxonase 1 (PON1) Met-54 allele with Parkinson's disease

Paraoxonase1 (PON1) is an arylesterase mainly expressed in the liver that hydrolyzes organophosphates such as pesticides, reported risk factors for Parkinson's disease (PD), and other neurotoxins. A Leu-Met 54 polymorphism in the gene for PON1-affecting enzyme activity was recently shown, employing a new restriction enzyme technique, to be associated with Parkinson's disease. We examined the same polymorphism by automated capillary sequencing in a sample of Caucasian subjects from the Stockholm area in Sweden (127 healthy individuals and 114 patients with PD) and found similar distributions and a similar difference in our sample. The genotype distribution in our PD material was LL 36.0%, LM 45.6%, and MM 18.4%; in our control material, it was LL 45.7%, LM 44.1%, and MM 10.2%. Based on the previously established increase in allele frequencies of the lower-activity Met-variant of PON1, we could confirm a significant association using a one-sided chi(2) test. Results remained significant with a two-sided chi(2) test, allowing for both increases and decreases in frequencies. Our data confirm an association between the PON1 Leu-Met 54 polymorphism and PD by demonstrating a similar association. The distribution between familial and nonfamilial PD patients was equal. No other synonymous or nonsynonymous polymorphisms were found in the sequenced coding region of PON1.

NURR1 mutations in cases of schizophrenia and manic-depressive disorder

Transgenic mice lacking the nuclear orphan transcription factor Nur-related receptor 1 (Nurr1) fail to develop mesencephalic dopamine neurons. There is a highly homologous NURR1 gene in humans (formerly known as NOT) which therefore constitutes a good candidate gene for neurologic and psychiatric disorders with an involvement of the dopamine neuron system, such as Parkinson's disease, schizophrenia, and manic-depression. By direct sequencing of genomic DNA, we found two different missense mutations in the third exon of NURR1 in two schizophrenic patients and another missense mutation in the same exon in an individual with manic-depressive disorder. All three mutations caused a similar reduction of in vitro transcriptional activity of NURR1 dimers of about 30-40%. Neither of these amino acid changes, nor any sequence changes whatsoever, were found in patients with Parkinson's disease or control DNA material of normal populations. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:808-813, 2000.

NURR1 mutations in cases of schizophrenia and manic-depressive disorder

Transgenic mice lacking the nuclear orphan transcription factor Nur-related receptor 1 (Nurr1) fail to develop mesencephalic dopamine neurons. There is a highly homologous NURR1 gene in humans (formerly known as NOT) which therefore constitutes a good candidate gene for neurologic and psychiatric disorders with an involvement of the dopamine neuron system, such as Parkinson's disease, schizophrenia, and manic-depression. By direct sequencing of genomic DNA, we found two different missense mutations in the third exon of NURR1 in two schizophrenic patients and another missense mutation in the same exon in an individual with manic-depressive disorder. All three mutations caused a similar reduction of in vitro transcriptional activity of NURR1 dimers of about 30-40%. Neither of these amino acid changes, nor any sequence changes whatsoever, were found in patients with Parkinson's disease or control DNA material of normal populations. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:808-813, 2000.

NURR1 mutations in cases of schizophrenia and manic-depressive disorder

Transgenic mice lacking the nuclear orphan transcription factor Nur-related receptor 1 (Nurr1) fail to develop mesencephalic dopamine neurons. There is a highly homologous NURR1 gene in humans (formerly known as NOT) which therefore constitutes a good candidate gene for neurologic and psychiatric disorders with an involvement of the dopamine neuron system, such as Parkinson's disease, schizophrenia, and manic-depression. By direct sequencing of genomic DNA, we found two different missense mutations in the third exon of NURR1 in two schizophrenic patients and another missense mutation in the same exon in an individual with manic-depressive disorder. All three mutations caused a similar reduction of in vitro transcriptional activity of NURR1 dimers of about 30-40%. Neither of these amino acid changes, nor any sequence changes whatsoever, were found in patients with Parkinson's disease or control DNA material of normal populations. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:808-813, 2000.

Alcohol dehydrogenase alleles in Parkinson's disease

Mutations in alcohol dehydrogenase (ADH; EC 1.1.1.1) genes may be of interest in the etiology of Parkinson's disease (PD) because of the important role these enzymes play in retinoid and dopamine metabolism and/or aldehyde detoxification. The location of several alcohol dehydrogenase genes in a cluster on chromosome 4 lends further support to ADH genes being candidates for this disorder, because recently a form of autosomal-dominant parkinsonism has been mapped to this area. We sequenced the promoter and coding regions and part of the introns of the human class IV ADH gene in 10 patients with PD. Seven different polymorphisms were identified. These polymorphisms could be assigned to four alleles (A1-A4). We then determined the frequencies of those four alleles and the wild-type allele in 78 patients with PD and 130 control subjects and found a significant association of the A1 allele with PD (odds ratio = 2.87; 95% confidence interval = 1.35-6.08). In familial cases, the association was strongest (odds ratio = 4.86; 95% confidence interval = 1.89-12.75). Two patients were homozygous for A1 whereas none of the 130 control subjects was found to be homozygous. Our results show an association between a certain ADH4 (formerly known as ADH7 in humans) allele and PD. This suggests a role for genetic variations of ADH4 as risk factors for the development of PD. Our data also show that the observed polymorphisms alone are not sufficient to cause symptoms. Further genetic and/or environmental factors have to be involved.

Cefoperazone: A review of its in vitro antimicrobial activity, pharmacological properties and therapeutic efficacy

Cefoperazone is a new 'third generation' semisynthetic injectable cephalosporin. It has a broad spectrum of antibacterial activity which includes Pseudomonas aeruginosa (unlike older cephalosporins), along with the Enterobacteriaceae and other Gram-negative bacteria, Gram-positive bacteria and anaerobic bacteria. Unlike other cephalosporins, cefoperazone is excreted to a considerable extent by extrarenal mechanisms. Given by intravenous or intramuscular injection, cefoperazone is effective against a wide variety of infections caused by Gram-negative or Gram-positive aerobes, including infections of the biliary tract, and in many anaerobic infections. It is generally well tolerated, diarrhoea and skin rashes being the most frequently reported side effects.

Amoxycillin/clavulanic acid: a review of its antibacterial activity, pharmacokinetics and therapeutic use

Clavulanic acid is a beta-lactamase inhibitor produced from Streptomyces clavuligerus, which when combined with certain beta-lactam antibiotics extends their activity against bacteria which owe their resistance to the production of beta-lacatamases. In combination with amoxycillin it extends the antibacterial activity of amoxycillin to include beta-lactamase-producing strains, which are otherwise resistant, as well as amoxycillin-resistant species such as Bacteroides fragilis. The addition of clavulanic acid to amoxycillin occasionally extends (but does not decrease) the susceptibility of amoxycillin-sensitive bacteria. Clavulanic acid is adequately absorbed after oral administration and its basic pharmacokinetic characteristics are similar to those of amoxycillin. Preliminary therapeutic trials suggest that amoxycillin plus clavulanic acid is effective in urinary tract infections caused by amoxycillin-resistant organisms and in lower respiratory tract infections unresponsive to previous routine antibiotic therapy, in hospitalised patients. It is generally well tolerated; nausea, vomiting, diarrhoea and skin rash being the most frequently reported adverse effects.