Angiotensin II type 1 receptor blockade ameliorates proteinuria in puromycin aminonucleoside nephropathy by inhibiting the reduction of NEPH1 and nephrin

BACKGROUND

The precise pathogenic mechanism and role of angiotensin II (Ang II) action in the development of proteinuria in minimal change nephrotic syndrome (MCNS) is uncertain.

METHODS

The glomerular expressions of the slit diaphragm (SD) molecules nephrin, podocin and NEPH1 in rat puromycin aminonucleoside (PAN) nephropathy, a mimic of MCNS, were analyzed. The effects of Ang II receptor blockade (ARB) (irbesartan 15 mg/kg body weight/day) on proteinuria and on the expression of the SD molecules were analyzed.

RESULTS

mRNA expressions of nephrin, podocin and NEPH1 were decreased to an undetectable level at 1 h. The staining of these SD molecules shifted to a discontinuous pattern, and their intensity was reduced. NEPH1 staining was reduced to an undetectable level on day 10. ARB treatment ameliorated the peak value of proteinuria (237.6 ± 97.0 vs. 359.0 ± 63.3 mg/day, p < 0.05), and prevented the decrease in the mRNA expression of the SD molecules (nephrin 66.96 %, podocin 60.40 %, NEPH1 77.87 % of normal level). The immunofluorescence staining of NEPH1 was restored by ARB. ARB treatment enhanced the expression of NEPH1 of normal rats.

CONCLUSIONS

Dysfunction of the SD molecules including NEPH1 is a crucial initiation event of PAN nephropathy. ARB treatment ameliorates proteinuria in PAN nephropathy by inhibiting the reduction of NEPH1 and nephrin. Ang II action regulates the expression of NEPH1 and nephrin in not only the pathological but also physiological state.

Pigmentation and behavior: potential association through pleiotropic genes in Drosophila

The molecular basis of pigmentation variation within and among Drosophila species is largely attributed to genes in melanin biosynthesis pathway, which involves dopamine metabolism. Most of the genetic changes underlying pigmentation variations reported to date are changes at the expression levels of the structural genes in the pathway. Within D. melanogaster, changes in cis-regulatory regions of a gene, ebony, are responsible for the naturally occurring variation of the body pigmentation intensity. This gene is also known to be expressed in glia, and many visual and behavioral abnormalities of its mutants have been reported. This implies that the gene has pleiotropic functions in the nervous systems. In this review, current knowledge on pigmentation variation and melanin biosynthesis pathway are summarized, with some focus on pleiotropic features of ebony and other genes in the pathway. A potential association between pigmentation and behavior through such pleiotropic genes is discussed in light of cis-regulatory structure and pleiotropic mutations.

Two Japanese cases of birt-hogg-dubé syndrome with pulmonary cysts, fibrofolliculomas, and renal cell carcinomas

Birt-Hogg-Dubé syndrome (BHD) is a rare autosomal dominant inherited disease caused by a germline mutation in the folliculin gene mapped in the region of chromosome 17p11.2. BHD predisposes the patient to cutaneous fibrofolliculomas (FFs), pulmonary cysts (PCs), and renal cell carcinoma (RC). Here, we present two cases of BHD in Japanese patients. One patient was a 37-year-old female, and the other a 35-year-old male. Each of the patients was affected by all three symptoms of BHD. Both patients had unremarkable FFs, asymptomatic PCs, and asymptomatic RC. The presence of RC was revealed by abdominal ultrasonic examination. We also summarized the data from 62 Asian cases of BHD from the available literature and found that their FFs were unremarkable. In addition, the proportion of BHD patients with FF is smaller for Asian patients than it is for Caucasian patients. We also found that it is rare for BHD patients in Asia to show all three symptoms of BHD. Careful inspection of the skin as well as skin biopsies are important for the early detection of BHD cases in Asia.

Decreased sudomotor function is involved in the formation of atopic eczema in the cubital fossa

BACKGROUND

Eczema in the cubital fossa, which is susceptible to sweat, is frequently observed in atopic dermatitis (AD). However, there has been no direct evidence that sweating causes eczema in the cubital fossa.

METHODS

To investigate this issue, axon reflex-mediated sweating volume (AXR) and skin barrier function in the cubital fossa were measured in subjects with AD and in healthy volunteers, and were applied to clinical feature of the cubital fossa.

RESULTS

AXR in the cubital fossa decreased in AD subjects; it positively correlated only with water-holding capacity in healthy subjects but not in patients with in AD. Furthermore, AD subjects with lichenoid eczema and either prurigo or papules over the cubital fossa showed extremely decreased AXR.

CONCLUSIONS

These results suggest that decreased sweating is a major source of water in the stratum corneum, and decreased sudomotor function may be involved in both the cause and aggravation of representative atopic eczema in the cubital fossa.

Proton-exchange mechanism of specific Cs+ adsorption via lattice defect sites of Prussian blue filled with coordination and crystallization water molecules

We have revealed the fundamental mechanism of specific Cs(+) adsorption into Prussian blue (PB) in order to develop high-performance PB-based Cs(+) adsorbents in the wake of the Fukushima nuclear accident. We compared two types of PB nanoparticles with formulae of Fe(III)4[Fe(II)(CN)6]3·xH2O (x = 10-15) (PB-1) and (NH4)0.70Fe(III)1.10[Fe(II)(CN)6]·1.7H2O (PB-2) with respect to the Cs(+) adsorption ability. The synthesised PB-1, by a common stoichiometric aqueous reaction between 4Fe(3+) and 3[Fe(II)(CN)6](4-), showed much more efficient Cs(+) adsorption ability than did the commercially available PB-2. A high value of the number of waters of crystallization, x, of PB-1 was caused by a lot of defect sites (vacant sites) of [Fe(II)(CN)6](4-) moieties that were filled with coordination and crystallization water molecules. Hydrated Cs(+) ions were preferably adsorbed via the hydrophilic defect sites and accompanied by proton-elimination from the coordination water. The low number of hydrophilic sites of PB-2 was responsible for its insufficient Cs(+) adsorption ability.

Dynamic analysis of histamine-mediated attenuation of acetylcholine-induced sweating via GSK3β activation

Sweating has been associated with the exacerbation of atopic dermatitis (AD) in diverse ways. Acetylcholine (ACh)-mediated sweating is known to be attenuated in AD, but its cause remains obscure. To address this issue, the impact of histamine on ACh-induced sweating was evaluated. Sweating was measured by counting the number of active sweat pores by the starch-iodine reaction and dynamic optical coherence tomography; sweat was visualized using two-photon excitation fluorescence microscopy in mice and the quantitative sudomotor axon reflex test in humans. Both histamine receptor antagonists and H1 receptor (H1R)-knockout (KO) mice were used to determine methodological specificity. Histamine demonstrably inhibited ACh-induced sweating in both mice and humans via H1R-mediated signaling. In sweat glands, ACh inactivated glycogen synthase kinase 3β (GSK3β), a kinase involved in endocytosis and secretion, whereas simultaneous stimulation with histamine activated GSK3β. Results of two-photon excitation fluorescence microscopy confirmed the dynamic motion of sweat and sweat glands after ACh treatment, showing that simultaneous stimulation with histamine altered their dynamic properties. These results indicate that histamine inhibits sweat gland secretions by blocking ACh-induced inactivation of GSK3β. Histamine-mediated hypohidrosis might be involved in the mechanism of abnormal skin dryness in patients with AD.

Preferential expression of cancer/testis genes in cancer stem-like cells: proposal of a novel sub-category, cancer/testis/stem gene

Cancer/testis (CT) antigens encoded by CT genes are immunogenic antigens, and the expression of CT gene is strictly restricted to only the testis among mature organs. Therefore, CT antigens are promising candidates for cancer immunotherapy. In a previous study, we identified a novel CT antigen, DNAJB8. DNAJB8 was found to be preferentially expressed in cancer stem-like cells (CSCs)/cancer-initiating cells (CICs), and it is thus a novel CSC antigen. In this study, we hypothesized that CT genes are preferentially expressed in CSCs/CICs rather than in non-CSCs/-CICs and we examined the expression of CT genes in CSCs/CICs. The expression of 74 CT genes was evaluated in side population (SP) cells (=CSC) and main population (MP) cells (=non-CSC) derived from LHK2 lung adenocarcinoma cells, SW480 colon adenocarcinoma cells and MCF7 breast adenocarcinoma cells by RT-PCR and real-time PCR. Eighteen genes (MAGEA2, MAGEA3, MAGEA4, MAGEA6, MAGEA12, MAGEB2, GAGE1, GAGE8, SPANXA1, SPANXB1, SPANXC, XAGE2, SPA17, BORIS, PLU-1, SGY-1, TEX15 and CT45A1) showed higher expression levels in SP cells than in MP cells, whereas 10 genes (BAGE1, BAGE2, BAGE4, BAGE5, XAGE1, LIP1, D40, HCA661, TDRD1 and TPTE) showed similar expression levels in SP cells and MP cells. Thus, considerable numbers of CT genes showed preferential expression in CSCs/CICs. We therefore propose a novel sub-category of CT genes in this report: cancer/testis/stem (CTS) genes.

The octadecaneuropeptide stimulates somatolactin release from cultured goldfish pituitary cells

The present study aimed to investigate the distribution of the octadecaneuropeptide (ODN) in the goldfish brain and to look for a possible effect of ODN on somatolactin (SL) release from pituitary cells. A discrete population of ODN-immunoreactive neurones was localised in the lateral part of the nucleus lateralis tuberis. These neurones sent projections through the neurohypophyseal tract towards the neurohypophysis, and nerve fibres were seen in the close vicinity of SL-producing cells in the pars intermedia. Incubation of cultured goldfish pituitary cells with graded concentrations of ODN (10(-9) -10(-5 ) m) induced a dose-dependent stimulation of SL-β, but not SL-α, release. ODN-evoked SL release was blocked by the metabotrophic endozepine receptor antagonist cyclo(1-8) [DLeu(5) ]OP but was not affected by the central-type benzodiazepine receptor antagonist flumazenil. ODN-induced SL release was suppressed by treatment with the phospholipase C (PLC) inhibitor U-73122 but not with the protein kinase A (PKA) inhibitor H-89. These results indicate that, in fish, ODN produced by hypothalamic neurones acts as a hypophysiotrophic neuropeptide stimulating SL release. The effect of ODN is mediated through a metabotrophic endozepine receptor positively coupled to the PLC/inositol 1,4,5-trisphosphate/protein kinase C-signalling pathway.

Scleral thickness in highly myopic eyes measured by enhanced depth imaging optical coherence tomography

PURPOSE

The purpose of this study was to determine the subfoveal scleral thickness in highly myopic eyes by enhanced depth imaging spectral-domain optical coherence tomography (EDI-OCT) and to identify the ocular parameters significantly associated with the scleral thickness.

METHODS

The subfoveal scleral thickness of myopic eyes (≥-8 diopters (D) or axial length ≥26.5 mm) was examined by EDI-OCT. The correlations between the thickness and the best-corrected visual acuity (BCVA), refractive error, axial length (AL), the subfoveal retinal thickness, choroidal thickness, and posterior staphyloma height 2 mm from the fovea were investigated.

RESULTS

A total of 75 eyes of 54 patients (21 men, 33 women; mean age, 62.3±11.3 years; mean AL, 30.2±1.68 mm) were studied. Eighteen eyes had no pathological retinochoroidal lesions, and 57 eyes had retinochoroidal lesion, that is, myopic schisis, choroidal neovascularization, and other retinochoroidal pathologies. The mean subfoveal scleral thickness was 284.0±70.4 μm, and the thickness was significantly correlated negatively with the absolute value of the nasal and overall average posterior staphyloma height (P<0.05 and P<0.01, respectively). The subfoveal scleral thickness was also significantly correlated negatively with the relative value of the superior, nasal, and overall average posterior staphyloma height (P<0.05, P<0.01, and P<0.001, respectively). Stepwise analyses showed that the factor most significantly associated with the scleral thickness was the average relative posterior staphyloma height (F=16.0, P<0.001). The scleral thickness was not significantly different between eyes with and without myopic retinochoroidal pathologies (P>0.05).

CONCLUSION

Posterior staphyloma formation was a key factor associated with a posterior scleral thinning in highly myopic eyes.

[Beating mitral valve surgery in patients with poor left ventricular function]

Mitral valve surgery is usually performed under the arrested heart condition. However, cardioplegic arrest techniques will inevitably produce some degree of reperfusion injury. We expected that keeping heart beating decrease the reperfusion injury in patients with poor left ventricular function. The present study compared the results of beating heart technique and conventional mitral valve surgery to demonstrate the merit of this technique. Thirty six patients with low left ventricular function[ ejection fraction (EF)≤35%] who underwent mitral valve surgery between April 2004 and July 2012 were enrolled in this study. On-pump beating mitral valve surgery were performed in 21 patients (beating group). Fifteen patients underwent conventional mitral valve surgery with cardiac arrest using blood cardioplegia (arrest group). Postoperative cardiac events in the beating group were less than that in the arrest group. However, this difference in both groups was not statistically significant. The visual field of the beating heart was equal to that of conventional surgery, and technical accuracy was not compromised. To decrease postoperative cardiac events, beating-heart mitral valve surgery may be suitable surgical option for patients with poor left ventricular function.

Abnormal axon reflex-mediated sweating correlates with high state of anxiety in atopic dermatitis

BACKGROUND

Sweating plays a key role in skin homeostasis, including antimicrobial and moisturizing effects, and regulation of skin surface pH. Impaired axon reflex-mediated (AXR) sweating has been observed in patients with atopic dermatitis (AD). However, the mechanism of such abnormal sudomotor axon reflex remains to be revealed.

METHODS

To investigate this mechanism, sudomotor function was analyzed using a quantitative sudomotor axon reflex test (acetylcholine iontophoresis) in patients with AD (n = 26) and healthy volunteers (n = 12). Correlation between sudomotor function and certain background factors, including Spielberger State Trait Anxiety Inventory score, Severity Scoring of Atopic Dermatitis (SCORAD) score, number of circulating eosinophils, and serum concentrations of thymus and activation-regulated chemokine and immunoglobulin E radioimmunosorbent test, was validated.

RESULTS

Latency time was significantly prolonged in AD (p = 0.0352), and AXR sweating volume (mg/0-5 min) was significantly lower in AD patients than in healthy controls (p = 0.0441). Direct sweating volume (mg/0-5 min) was comparable in AD patients and healthy controls. A significant correlation between the evaluation results of quantitative sudomotor axon reflex tests and certain background factors was not observed. The latency time in non-lesioned and lesioned areas for AD patients versus continuous anxiety value in the Spielberger State Trait Anxiety Inventory and the AXR versus SCORAD showed significant correlations (p = 0.0424, p = 0.0169, and p = 0.0523, respectively).

CONCLUSIONS

Although the number of study subjects was little, abnormal AXR sweating in patients with AD was observed. Correlative analysis suggests possible involvement of continuous anxiety and the immune system in such abnormal sudomotor function.

Postoperative transient reduced diffusion in the ipsilateral striatum and thalamus

BACKGROUND AND PURPOSE

Restriction of diffusion has been reported in the early phase of secondary neuronal degeneration, such as wallerian degeneration. The purpose of this study was to investigate postoperative transient reduced diffusion in the ipsilateral striatum and thalamus as a remote effect of surgery.

MATERIALS AND METHODS

Six hundred two postoperative MR imaging examinations in 125 patients after cerebral surgery were retrospectively reviewed, focusing on the presence of reduced diffusion in the striatum and/or thalamus. The distribution of reduced diffusion in the striatum was classified into 3 groups: anterior, central, and posterior. Reduced diffusion in the thalamus was also classified on the basis of the anatomic locations of the thalamic nuclei. Further follow-up MRI was available in all patients with postoperative reduced diffusion, and acute infarctions were excluded. The patient medical records were reviewed to evaluate neurologic status.

RESULTS

Restriction of diffusion was observed in the striatum and/or thalamus ipsilateral to the surgical site in 17 patients (13.6%). The distribution of signal abnormality correlated with the location of the operation, in concordance with the architecture of the striatocortical and thalamocortical connections. Reduced diffusion was observed from days 7 to 46 after the operation, especially during days 8-21. The signal abnormalities completely resolved on follow-up examinations. The median follow-up period was 202 days (interquartile range, 76-487 days).

CONCLUSIONS

Postoperative transient reduced diffusion in the ipsilateral striatum and/or thalamus likely represents an early phase of secondary neuronal degeneration based on its characteristic distribution and time course. Clinically, this reduced diffusion should not be mistaken for postoperative ischemic injury.

Cortactin, an actin binding protein, regulates GLUT4 translocation via actin filament remodeling

Insulin regulates glucose uptake into fat and skeletal muscle cells by modulating the translocation of GLUT4 between the cell surface and interior. We investigated a role for cortactin, a cortical actin binding protein, in the actin filament organization and translocation of GLUT4 in Chinese hamster ovary (CHO-GLUT4myc) and L6-GLUT4myc myotube cells. Overexpression of wild-type cortactin enhanced insulin-stimulated GLUT4myc translocation but did not alter actin fiber formation. Conversely, cortactin mutants lacking the Src homology 3 (SH3) domain inhibited insulin-stimulated formation of actin stress fibers and GLUT4 translocation similar to the actin depolymerizing agent cytochalasin D. Wortmannin, genistein, and a PP1 analog completely blocked insulin-induced Akt phosphorylation, formation of actin stress fibers, and GLUT4 translocation indicating the involvement of both PI3-K/Akt and the Src family of kinases. The effect of these inhibitors was even more pronounced in the presence of overexpressed cortactin suggesting that the same pathways are involved. Knockdown of cortactin by siRNA did not inhibit insulin-induced Akt phosphorylation but completely inhibited actin stress fiber formation and glucose uptake. These results suggest that the actin binding protein cortactin is required for actin stress fiber formation in muscle cells and that this process is absolutely required for translocation of GLUT4-containing vesicles to the plasma membrane.

The 5'-flanking region of the RP58 coding sequence shows prominent promoter activity in multipolar cells in the subventricular zone during corticogenesis

Pyramidal neurons of the neocortex are produced from progenitor cells located in the neocortical ventricular zone (VZ) and subventricular zone (SVZ) during embryogenesis. RP58 is a transcriptional repressor that is strongly expressed in the developing brain and plays an essential role in corticogenesis. The expression of RP58 is strictly regulated in a time-dependent and spatially restricted manner. It is maximally expressed in E15-16 embryonic cerebral cortex, localized specifically to the cortical plate and SVZ of the neocortex, hippocampus, and parts of amygdala during brain development, and found in glutamatergic but not GABAergic neurons. Identification of the promoter activity underlying specific expression patterns provides important clues to their mechanisms of action. Here, we show that the RP58 gene promoter is activated prominently in multipolar migrating cells, the first in vivo analysis of RP58 promoter activity in the brain. The 5.3 kb 5'-flanking genomic DNA of the RP58 coding region demonstrates promoter activity in neurons both in vitro and in vivo. This promoter is highly responsive to the transcription factor neurogenin2 (Ngn2), which is a direct upstream activator of RP58 expression. Using in utero electroporation, we demonstrate that RP58 gene promoter activity is first detected in a subpopulation of pin-like VZ cells, then prominently activated in migrating multipolar cells in the multipolar cell accumulation zone (MAZ) located just above the VZ. In dissociated primary cultured cortical neurons, RP58 promoter activity mimics in vivo expression patterns from a molecular standpoint that RP58 is expressed in a fraction of Sox2-positive progenitor cells, Ngn2-positive neuronal committed cells, and Tuj1-positive young neurons, but not in Dlx2-positive GABAergic neurons. Finally, we show that Cre recombinase expression under the control of the RP58 gene promoter is a feasible tool for conditional gene switching in post-mitotic multipolar migrating young neurons in the developing cerebral cortex.

Tuberothalamic artery infarctions following coil embolization of ruptured posterior communicating artery aneurysms with posterior communicating artery sacrifice

BACKGROUND AND PURPOSE

Ischemic complications after coil embolization of the PcomA aneurysms are not thoroughly understood, especially in cases in which the PcomA is sacrificed. Our purpose was to examine the preoperative angiographic features and pattern of postoperative cerebral infarctions exhibited by patients who underwent embolization of ruptured PcomA aneurysms with PcomA sacrifice.

MATERIALS AND METHODS

A retrospective review identified 14 patients with ruptured PcomA aneurysms who underwent embolization of the aneurysms in combination with PcomA sacrifice. Preoperative angiographic data, including the Allcock test, postoperative DWI, and neurologic status, were examined.

RESULTS

Elimination of the aneurysm was complete in all cases. Postoperative DWI indicated 7 cases with infarctions (infarction group) and 7 cases without infarctions (noninfarction group). All patients in the infarction group developed infarctions in the vicinity of the tuberothalamic artery. In all 14 cases, a preoperative Allcock test demonstrated a retrograde filling of the PcomA through the P1 segment. The incidence of negative visualizations of the P1 segment on vertebral angiograms was significantly higher in the infarction group (100%) than in the noninfarction group (0%; P = .00058). The mean PcomA diameters, PcomA/P1 ratios, and aneurysm sizes observed in the infarction group were significantly greater than those in the noninfarction group (P < .05, P < .01, and P < .02, respectively). Tuberothalamic artery infarction caused hemiparesis and memory disturbance, which were associated with unfavorable outcomes.

CONCLUSIONS

After the coil occlusion of ruptured PcomA aneurysms with PcomA sacrifice, tuberothalamic artery infarctions tended to occur in cases exhibiting negative visualization of the P1 segment, even when collateral flow was observed with the Allcock test.

Dynamic instability of central airways and peripheral airspace in rat lungs perfused with cold preservation solutions

BACKGROUND/AIMS

For lung preservation, one of two types of solutions is commonly employed: Euro-Collins (EC) or low potassium dextran glucose (LPDG). These two solutions have been compared regarding biological, morphometrical and physiological outcomes in many experiments. However, the dynamic mechanics of perfused lung are not well understood because the dynamic characteristics cannot be assessed under static conditions; hence, the primary goal of the present study was to assess this in perfused rat lungs during the preservation period, comparing EC with LPDG at 0 or 9 h at 4°C.

METHODS

Lung impedance was measured using a forced oscillation technique. Lung resistance and elastance values were obtained by the fast Fourier transform algorithm. The instability of central airways and heterogeneity of ventilation were estimated.

RESULTS

In the EC group, airway resistance and instability were high after perfusion, and the lung elastance was high and more heterogeneous after cold storage. In contrast, those parameters were stable in the LPDG group during cold storage.

CONCLUSION

Such dynamic stability might facilitate the handling of lung grafts and eliminate injurious cyclic ventilation stress after reperfusion. Thus, we conclude that the impedance frequency characteristic represents a novel informative parameter for investigating lung preservation techniques.

Divergent enhancer haplotype of ebony on inversion In(3R)Payne associated with pigmentation variation in a tropical population of Drosophila melanogaster

The pattern and intensity of pigmentation have direct impact on individual fitness through various ecological factors. In a Drosophila melanogaster population from southern Japan, thoracic trident pigmentation intensity of most of the strains could be classified into Dark or Light-type. The expression level variation of the ebony gene correlated well with this phenotype and the allelic differences in expression indicated that the variation is partly due to cis-regulatory changes. In the ∼13 kb gene region, we identified 17 nucleotide sites and 2 indels that were in complete association with the thoracic trident pigmentation intensity. Interestingly, 11 out of 19 sites located within ∼0.5 kb of the core epidermis enhancer. These sites had no obvious association with the abdominal pigmentation intensity in the previously analysed African populations from Uganda and Kenya, which suggested that multiple potential mutational pathways in the cis-regulatory control region of a single gene could lead to similar phenotypic variation within this species. We also found that the Light-type enhancer haplotype is strongly linked to a cosmopolitan inversion, In(3R)Payne, which is predominant in warmer climatic regions in both hemispheres. The sequence pattern suggested that the strong linkage may be due to selective forces related to thermal adaptation. The inferred selection for lighter pigmentation in the Japanese population is in the opposite direction of the previously reported case of selection for darker individuals in African populations. Nevertheless, both adaptive changes involved cis-regulatory changes of ebony, which shows that this gene is likely to be a common target of natural selection.

Claudin as a target for drug development

Tight junctions (TJs) play pivotal roles in the fence and barrier functions of epithelial and endothelial cell sheets. Since the 1980s, the modulation of the TJ barrier has been utilized as a method for drug absorption. Over the last decade, the structural and functional biochemical components of TJs, such as occludin and claudin, have been determined, providing new insights into TJ-based pharmaceutical therapy. For example, the modulation of the claudin barrier enhances the jejunal absorption of drugs, and claudin expression is deregulated in cancer cells. Claudin is a co-receptor for the hepatitis C virus. Moreover, claudin is modulated during inflammatory conditions. These findings indicate that claudins are promising drug targets. In this review, we discuss the seeds of claudin-based drug development, which may provide potential pharmaceutical breakthroughs in the future.

Genome-wide association study on bipolar disorder in the Bulgarian population

Bipolar disorder is a severe psychiatric disorder influenced by environmental and genetic factors. Genetic studies have implicated many variants in the disease's etiology but only few have been successfully replicated. We conducted a genome-wide association study (GWAS) on bipolar disorder in the Bulgarian population followed by a replication study of the top 100 single nucleotide polymorphisms (SNPs) showing the smallest P values. The GWAS was performed on 188 bipolar disorder patients and 376 control subjects genotyped on the Illumina 550 platform. The replication study was conducted on 122 patients and 328 controls. Although our study did not show any association P value that achieved genome-wide significance, and none of the top 100 SNPs reached the Bonferroni-corrected P value in the replication study, the plausible involvement of some variants cannot be entirely discarded. Three polymorphisms, rs8099939 [P = 2.12 × 10(-6), odds ratio (OR) = 1.95, 95% confidence interval (CI) = 1.43-2.67] in GRIK5, rs6122972 (P = 3.11 × 10(-6), OR = 2.02, 95% CI = 1.46-2.80) in PARD6B and rs2289700 (P = 9.14 × 10(-6), OR = 2.13, 95% CI = 1.53-2.95) in CTSH remained associated at a similar level after Mantel-Haenszel test for combining the results from the genome-wide and replication studies. A modest association was also detected for SNP rs1012053 (GWAS P = 4.50 × 10(-2)) in DGKH, which has already been reported as the most significant variant in a previous genome-wide scan on bipolar disorder. However, further studies using larger datasets are needed to identify variants with smaller effects that contribute to the risk of bipolar disorder.