Analysis of single nucleotide polymorphism rs415430 in the WNT3 gene in the Russian population with the Parkinson disease

The Parkinson disease (PD) is the second most common progressive neurodegenerative disorder that arises due to degeneration of dopaminergic neurons. The causes of this disease are still unknown, but a number of genes involved in pathogenesis of familial and sporadic forms of PD has been identified. According to recent data of genome wide association studies (GWAS), single nucleotide polymorphisms (SNPs) in these genes (including MAPT locus) may play an important role in the development of PD. Therefore, we analyzed distribution of genotype frequencies of SNP rs415430 in the WNT3 gene in the Russian patients with sporadic PD and in the Russian population controls (OR = 0.84, Confidence Interval (95% CI) 0.58-1.23, p = 0.39). It was concluded that SNP rs415430 in the WNT3 gene was not associated with the risk of development of PD.     

Synthesis and photochemical transformation of 3β,21-dihydroxypregna-5,7-dien-20-one to novel secosteroids that show anti-melanoma activity

We have synthesized 3β,21-dihydroxypregna-5,7-dien-20-one (21(OH) 7DHP) and used UVB radiation to induce its photoconversion to analogues of vitamin D (pD), lumisterol (pL) and tachysterol (pT). The number and character of the products and the dynamics of the process were dependent on the UVB dose. The main products: pD and pT compounds were characterized by UV absorption, MS and NMR spectroscopy after RP-HPLC chromatography. In addition, formation of multiple oxidized derivatives of the primary products was detected and one of these derivatives was characterized as oxidized 21-hydroxyisotachysterol compound (21(OH)oxy-piT). These newly synthesized compounds inhibited growth of human melanoma cells in a dose dependent manner, with greater or equal potency to calcitriol. 3β,21-Dihydroxy-9β,10α-pregna-5,7-dien-20-one (21(OH)pL) and 21(OH)oxy-piT had higher potency against pigmented melanoma cells, while the EC(50) for compounds 21(OH)7DHP and (5Z,7E)-3β,21-dihydroxy-9,10-secopregna-5,7,10(19)-trien-20-one (21(OH)pD) were similar in both pigmented and non-pigmented cells. Moreover, 21(OH)7DHP and its derivatives inhibited proliferation of human epidermal HaCaT keratinocytes, albeit at a lower activity compared to melanoma cells. Importantly, 21(OH)7DHP derivatives strongly inhibited the colony formation of human melanoma cells with 21(OH)pD being the most potent. The potential mechanism of action of newly synthesized compounds was similar to that mediated by 1,25(OH)(2)D(3) and involved ligand-induced translocation of vitamin D receptor into the nucleus. In summary, we have characterized for the first time products of UVB-induced conversion of 21(OH)7DHP and documented that these compounds have selective, inhibitory effects on melanoma cells.     

Polymorphic variants of ALOX5AP gene and the risk of acute stroke development in the Russian population

A protein capable of activating 5-lipoxygenase (ALOX5AP) is considered a presumable risk factor of acute stroke development. Polymorphic variants of the ALOX5AP gene were examined. Two ALOX5AP gene polymorphisms (SG13S114 (rs10507391) and SG13S32 (rs9551963)), which previously had shown association with the risk of ischemic stroke in other populations, were studied. These single nucleotide polymorphisms were analyzed using a sample of acute stroke patients (N = 1320) and a control sample (N = 467). No statistically significant associations were found between acute stroke and the ALOX5AP gene polymorphisms examined.     

CRH functions as a growth factor/cytokine in the skin

We tested the effect of CRH and related peptides in a large panel of human skin cells for growth factor/cytokine activities. In skin cells CRH action is mediated by CRH-R1, a subject to posttranslational modification with expression of alternatively spliced isoforms. Activation of CRH-R1 induced generation of both cAMP and IP3 in the majority of epidermal and dermal cells (except for normal keratinocytes and one melanoma line), indicating cell type-dependent coupling to signal transduction pathways. Phenotypic effects on cell proliferation were however dependent on both cell type and nutrition conditions. Specifically, CRH stimulated dermal fibroblasts proliferation, by increasing transition from G1/0 to the S phase, while in keratinocytes CRH inhibited cell proliferation. In normal and immortalized melanocytes CRH effect showed dichotomy and thus, it inhibited melanocyte proliferation in serum-containing medium CRH through G2 arrest, while serum free media led instead to CRH enhanced DNA synthesis (through increased transition from G1/G0 to S phase and decreased subG1 signal, indicating DNA degradation). CRH also induced inhibition of early and late apoptosis in the same cells, demonstrated by analysis with the annexin V stains. Thus, CRH acts on epidermal melanocytes as a survival factor under the stress of starvation (anti-apoptotic) as well as inhibitor of growth factors induced cell proliferation. In conclusion, CRH and related peptides can couple CRH-R1 to any of diverse signal transduction pathways; they also regulate cell viability and proliferation in cell type and growth condition-dependent manners.     

Boosting Cortical Activity at Beta-Band Frequencies Slows Movement in Humans

Neurons have a striking tendency to engage in oscillatory activities. One important type of oscillatory activity prevalent in the motor system occurs in the beta frequency band, at about 20 Hz. It is manifest during the maintenance of tonic contractions and is suppressed prior to and during voluntary movement [1], [2], [3], [4], [5], [6] and [7]. This and other correlative evidence suggests that beta activity might promote tonic contraction, while impairing motor processing related to new movements [3], [8] and [9]. Hence, bursts of beta activity in the cortex are associated with a strengthening of the motor effects of sensory feedback during tonic contraction and with reductions in the velocity of voluntary movements [9], [10] and [11]. Moreover, beta activity is increased when movement has to be resisted or voluntarily suppressed [7], [12] and [13]. Here we use imperceptible transcranial alternating-current stimulation to entrain cortical activity at 20 Hz in healthy subjects and show that this slows voluntary movement. The present findings are the first direct evidence of causality between any physiological oscillatory brain activity and concurrent motor behavior in the healthy human and help explain how the exaggerated beta activity found in Parkinson's disease can lead to motor slowing in this illness [14].     

Cutaneous expression of corticotropin-releasing hormone (CRH), urocortin, and CRH receptors.

Studies in mammalian skin have shown expression of the genes for corticotropin-releasing hormone (CRH) and the related urocortin peptide, with subsequent production of the respective peptides. Recent molecular and biochemical analyses have further revealed the presence of CRH receptors (CRH-Rs). These CRH-Rs are functional, responding to CRH and urocortin peptides (exogenous or produced locally) through activation of receptor(s)-mediated pathways to modify skin cell phenotype. Thus, when taken together with the previous findings of cutaneous expression of POMC and its receptors, these observations extend the range of regulatory elements of the hypothalamic-pituitary-adrenal axis expressed in mammalian skin. Overall, the cutaneous CRH/POMC expression is highly reactive to common stressors such as immune cytokines, ultraviolet radiation, cutaneous pathology, or even the physiological changes associated with the hair cycle phase. Therefore, similar to its central analog, the local expression and action of CRH/POMC elements appear to be highly organized and entrained, representing general mechanism of cutaneous response to stressful stimuli. In such a CRH/POMC system, the CRH-Rs may be a central element.     

Kinetics of vitamin D3 metabolism by cytochrome P450scc (CYP11A1) in phospholipid vesicles and cyclodextrin

Vitamin D3 can be hydroxylated sequentially by cytochrome P450scc (CYP11A1) producing 20-hydroxyvitamin D3, 20,23-dihydroxyvitamin D3 and 17,20,23-trihydroxyvitamin D3. The aim of this study was to characterize the ability of vitamin D3 to associate with phospholipid vesicles and to determine the kinetics of metabolism of vitamin D3 by P450scc in vesicles and in 2-hydroxypropyl-beta-cyclodextrin (cyclodextrin). Gel filtration of phospholipid vesicles showed that the vitamin D3 remained quantitatively associated with the phospholipid membrane. Vitamin D3 exchanged between vesicles at a rate 3.8-fold higher than for cholesterol exchange and was stimulated by N-62 StAR protein. The Km of P450scc for vitamin D3 in vesicles was 3.3 mol vitamin D3/mol phospholipid and the rate of conversion of vitamin D3 to 20-hydroxyvitamin D3 was first order with respect to the vitamin D3 concentration for the range of concentrations of vitamin D3 that could be incorporated into the vesicle membrane. 20-Hydroxyvitamin D3 was further hydroxylated by P450scc in vesicles, producing primarily 20,23-dihydroxyvitamin D3, with Km and kcat values 22- and 6-fold lower than those for vitamin D3, respectively. 20,23-dihydroxyvitamin D3 was converted to 17,20,23-trihydroxyvitamin D3 with even lower Km and kcat values. Vitamin D3 and cholesterol were metabolized with comparable efficiencies in cyclodextrin, but the Km for both showed a strong dependence on the cyclodextrin concentration, decreasing with decreasing cyclodextrin. This study shows that vitamin D3 quantitatively associates with phospholipid vesicles, can exchange between membranes, and can be hydroxylated by membrane-associated P450scc but with lower efficiency than for cholesterol hydroxylation. The kcat values for metabolism of vitamin D3 in vesicles and 0.45% cyclodextrin are similar, but the ability to solubilize vitamin D3 at a concentration higher than its Km makes the cyclodextrin system more efficient for producing the hydroxyvitamin D3 metabolites for further characterization.     

Effect of semax on the temporary dynamics of brain-derived neurotrophic factor and nerve growth factor gene expression in the rat hippocampus and frontal cortex

Semax is a synthetic peptide, which consists of the N-terminal adrenocorticotropic hormone fragment (4-7) (ACTH4-7) and C-terminal Pro-Gly-Pro peptide. Semax promotes neuron survival in hypoxia, increases selective attention and memory storage. It was shown that this synthetic peptide exerted a number of gene expressions, especially brain derived neurotrophic factor gene (Bdnf) and nerve growth factor gene (Ngf). Temporary dynamics of Bdnf and Ngf ex- pression in rat hippocampus and frontal cortex under Semax action (50 mg/kg, single intranasal administration) was studied in this work. It was shown that the studied gene expression levels changed significantly both in the hippocampus and the frontal cortex tissues 20 minutes after the peptide preparation application. The expression levels decreased in the hippocampus and increased in the frontal cortex. Forty minutes after Semax administration both gene expression levels returned to the level typical of control tissues. After that they increased significantly by 90 minutes after experiment start. Bdnf and Ngf expression levels decreased up to the control levels by 8 hours after medicine applying maximum gene expression levels were attained. Thus, Semax administration results in rapid, long-term, and specific activation of Bdnf and Ngf expression changes in different rat brain departments.     

Expansion and mutation rate in CTG repeats in the myotonic dystrophy gene

The CTG repeat of the myotonic dystrophy (MD) gene was analyzed in 62 MD patients and 54 healthy members of their families. A CTG repeat expansion was revealed in 57 (92%) patients and in 12 relatives who did not express clinical signs of MD. Family analysis showed that the CTG repeat number increased, which was associated with anticipation, decreased, or remained the same (17.6%) in alleles transmitted from parents to their children. The spontaneous mutation rate of the CTG repeat was estimated at 4 x 10(-2). Instability was characteristic of alleles with more than 19 repeated units.