Beneficial Effect of Intradialytic Electrical Muscle Stimulation in Hemodialysis Patients: A Randomized Controlled Trial.

Many hemodialysis (HD) patients cannot perform self-administered exercise training for their muscle wasting, weakness, and sarcopenia. Electrical muscle stimulation (EMS) has the advantages of easy application, and minimal risks for these patients. This study aimed to evaluate the effects of intradialytic EMS. This was a prospective, open-label, randomized controlled trial. Twenty-nine HD patients were randomly assigned to either the EMS group or the control (no training) group, and 13 patients in each group were eventually analyzed. The EMS group received intradialytic EMS over an 8-week period. Measurement of isometric knee extensor strength using a handheld dynamometer, evaluation of the quadriceps cross-sectional area (CSA) using magnetic resonance imaging (MRI), the Timed Up & Go Test (TUG) for physical function assessment, the Japanese version of the Short Form-8 Health Survey (SF-8), and blood tests were performed before and after the intervention period. The primary and secondary outcomes were improvement of quadriceps muscle strength and size, respectively. The EMS group demonstrated significant improvement compared with the control group in terms of knee extensor strength (right: 22.3 ± 12.8 vs. -10.8 ± 22.3 N, P < 0.001; left: 26.1 ± 29.7 vs. -8.3 ± 18.7 N, P < 0.001), quadriceps CSA at three positions, 25, 50, and 75% of the segment length from the greater trochanter to the inferior border of the lateral epicondyle of the femur (25% right: EMS group 1.7 ± 2.0 vs. Control group -0.4 ± 1.8cm2 , P = 0.05; 25% left: EMS group 1.3 ± 1.1 vs. Control group -0.6 ± 1.8cm2 , P = 0.01; 50% right: EMS group 2.0 ± 2.2 vs. Control group -0.7 ± 1.9cm2 , P = 0.004; 50% left: EMS group 2.7 ± 2.1 vs. Control group -0.7 ± 1.6cm2 , P = 0.001; 75% right: EMS group 1.8 ± 2.2 vs. Control group -0.7 ± 1.5cm2 , P = 0.003; 75% left: EMS group 2.1 ± 1.9 vs. Control group -0.4 ± 1.5cm2 , P = 0.003); and TUG time (-0.8 ± 0.6 vs. 0.2 ± 0.5s, P < 0.001). The EMS group showed improvement after intervention in all components of SF-8, but these were not statistically significant. EMS could be an effective exercise training tool for HD patients with either muscle wasting, weakness, or sarcopenia.

EphrinA/EphA signal facilitates insulin-like growth factor-I-induced myogenic differentiation through suppression of the Ras/extracellular signal-regulated kinase 1/2 cascade in myoblast cell lines.

Insulin-like growth factor-I (IGF-I) activates not only the phosphatidylinositol 3-kinase (PI3K)-AKT cascade that is essential for myogenic differentiation but also the extracellular signal-regulated kinase (ERK) 1/2 cascade that inhibits myogenesis. We hypothesized that there must be a signal that inhibits ERK1/2 upon cell-cell contact required for skeletal myogenesis. Cell-cell contact-induced engagement of ephrin ligands and Eph receptors leads to downregulation of the Ras-ERK1/2 pathway through p120 Ras GTPase-activating protein (p120RasGAP). We therefore investigated the significance of the ephrin/Eph signal in IGF-I-induced myogenesis. EphrinA1-Fc suppressed IGF-I-induced activation of Ras and ERK1/2, but not that of AKT, in C2C12 myoblasts, whereas ephrinB1-Fc affected neither ERK1/2 nor AKT activated by IGF-I. IGF-I-dependent myogenic differentiation of C2C12 myoblasts was potentiated by ephrinA1-Fc. In p120RasGAP-depleted cells, ephrinA1-Fc failed to suppress the Ras-ERK1/2 cascade by IGF-I and to promote IGF-I-mediated myogenesis. EphrinA1-Fc did not promote IGF-I-dependent myogenesis when the ERK1/2 was constitutively activated. Furthermore, a dominant-negative EphA receptor blunted IGF-I-induced myogenesis in C2C12 and L6 myoblasts. However, the inhibition of IGF-I-mediated myogenesis by down-regulation of ephrinA/EphA signal was canceled by inactivation of the ERK1/2 pathway. Collectively, these findings demonstrate that the ephrinA/EphA signal facilitates IGF-I-induced myogenesis by suppressing the Ras-ERK1/2 cascade through p120RasGAP in myoblast cell lines.

Mutant WDR36 directly affects axon growth of retinal ganglion cells leading to progressive retinal degeneration in mice.

Primary open-angle glaucoma (POAG) is one of the three principal subtypes of glaucoma and among the leading cause of blindness worldwide. POAG is defined by cell death of the retinal ganglion cells (RGCs) and surrounding neuronal cells at higher or normal intraocular pressure (IOP). Coded by one of the three genes responsible for POAG, WD repeat-containing protein 36 (WDR36) has two domains with a similar folding. To address whether WDR36 is functionally important in the retina, we developed four transgenic mice strains overexpressing a wild-type (Wt) and three mutant variants of D606G, deletion of amino acids at positions 605-607 (Del605-607) and at 601-640 (Del601-640) equivalent to the location of the D658G mutation observed in POAG patients. A triple amino acid deletion of mouse Wdr36 at positions 605-607 corresponding to the deletion at positions 657-659 in humans developed progressive retinal degeneration at the peripheral retina with normal IOP. RGCs and connecting amacrine cell synapses were affected at the peripheral retina. Axon outgrowth rate of cultured RGC directly isolated from transgenic animal was significantly reduced by the Wdr36 mutation compared with Wt. Molecular modeling of wild and mutant mouse Wdr36 revealed that deletion at positions 605-607 removed three residues and a hydrogen bond, required to stabilize anti-parallel ß-sheet of the 6th ß-propeller in the second domain. We concluded that WDR36 plays an important functional role in the retina homeostasis and mutation to this gene can cause devastating retinal damage. These data will improve understanding of the functional property of WDR36 in the retina and provide a new animal model for glaucoma therapeutics.

Overexpression of optineurin E50K disrupts Rab8 interaction and leads to a progressive retinal degeneration in mice.

Glaucoma is one of the leading causes of bilateral blindness affecting nearly 8 million people worldwide. Glaucoma is characterized by a progressive loss of retinal ganglion cells (RGCs) and is often associated with elevated intraocular pressure (IOP). However, patients with normal tension glaucoma (NTG), a subtype of primary open-angle glaucoma (POAG), develop the disease without IOP elevation. The molecular pathways leading to the pathology of NTG and POAG are still unclear. Here, we describe the phenotypic characteristics of transgenic mice overexpressing wild-type (Wt) or mutated optineurin (Optn). Mutations E50K, H486R and Optn with a deletion of the first (amino acids 153-174) or second (amino acids 426-461) leucine zipper were used for overexpression. After 16 months, histological abnormalities were exclusively observed in the retina of E50K mutant mice with loss of RGCs and connecting synapses in the peripheral retina leading to a thinning of the nerve fiber layer at the optic nerve head at normal IOP. E50K mice also showed massive apoptosis and degeneration of entire retina, leading to approximately a 28% reduction of the retina thickness. At the molecular level, introduction of the E50K mutation disrupts the interaction between Optn and Rab8 GTPase, a protein involved in the regulation of vesicle transport from Golgi to plasma membrane. Wt Optn and an active GTP-bound form of Rab8 complex were localized at the Golgi complex. These data suggest that alternation of the Optn sequence can initiate significant retinal degeneration in mice.

Angiopoietin-1/Tie2 receptor signaling in vascular quiescence and angiogenesis.

Angiopoietin (Ang) 1 is a ligand for endothelium-specific receptor tyrosine kinase Tie-2. In adult vasculature, Ang1/Tie2 signaling is thought to regulate both maintenance of vascular quiescence and promotion of angiogenesis. However, it has been unknown how Tie2 signal regulates these distinct biological functions. Recently, we and Alitalo's group have clarified that Ang1 assembles distinct Tie2 signaling complexes in either presence or absence of endothelial cell-cell adhesions. Ang1 induces trans-association of Tie2 at cell-cell contacts, whereas Tie2 is anchored to the extracellular matrix (ECM) by Ang1 at the cell-substratum interface. Trans-associated Tie2 and ECM-anchored Tie2 activate distinct signaling pathways. In this review, we discuss how Ang1/Tie2 signal regulates both maintenance of vascular quiescence and promotion of angiogenesis, especially focusing on the roles of trans-associated Tie2 and ECM-anchored Tie2.

Genetic analysis of typical wet-type age-related macular degeneration and polypoidal choroidal vasculopathy in Japanese population.

Age-related macular degeneration (AMD) is a common cause of blindness in the elderly. Caucasian patients are predominantly affected by the dry form of AMD, whereas Japanese patients have predominantly the wet form of AMD and/or polypoidal choroidal vasculopathy (PCV). Although genetic association in the 10q26 (ARMS2/HTRA1) region has been established in many ethnic groups for dry-type AMD, typical wet-type AMD, and PCV, the contribution of the 1q32 (CFH) region seem to differ among these groups. Here we show a single nucleotide polymorphism (SNP) in the ARMS2/HTRA1 locus is associated in the whole genome for Japanese typical wet-type AMD (rs10490924: p = 4.1 x 10(-4), OR = 4.16) and PCV (rs10490924: p = 3.7 x 10(-8), OR = 2.72) followed by CFH (rs800292: p = 7.4 x 10(-5), OR = 2.08; p = 2.6 x 10(-4), OR = 2.00), which differs from previous studies in Caucasian populations. Moreover, a SNP (rs2241394) in complement component C3 gene showed significant association with PCV (p = 2.5 x 10(-3), OR = 3.47). We conclude that dry-type AMD, typical wet-type AMD, and PCV have both common and distinct genetic risks that become apparent when comparing Japanese versus Caucasian populations. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s12177-009-9047-1) contains supplementary material, which is available to authorized users.

LOXL1 variants in elderly Japanese patients with exfoliation syndrome/glaucoma, primary open-angle glaucoma, normal tension glaucoma, and cataract.

PURPOSE: To evaluate the association of lysyl oxidase like 1 (LOXL1) gene variants in Japanese patients with open-angle glaucoma. METHODS: We evaluated the association of three LOXL1 variants (rs1048661, rs3825942, and rs2165241) in 142 Japanese patients with exfoliation syndrome (EX; n=59) and exfoliation glaucoma (EG; n=83) as well as in 251 control patients aged 70 years or older with primary open-angle glaucoma (PG; n=40), normal tension glaucoma (NG; n=54), and cataract (CT; n=157). RESULTS: In comparison with the CT group, the single nucleotide polymorphisms (SNPs) showed significant association with EX, EG, and EX+EG. The odds ratio (OR)=19.71-28.23 and p=1.69 x 10(-23) - 3.00 x 10(-45) for allele T of rs1048661; OR=28.21-39.78 and p=1.77 x 10(-8) - 2.42 x 10(-22) for allele G of rs3825942; and OR=16.59-23.40 and p=4.79 x 10(-5) - 1.08 x 10(-9) for allele C of rs2165241. In comparison with the controls (CT+PG+NG), the haplotype rs1048661/rs3825942 (T/G) was significantly associated with EX+EG (p=8.27 x 10(-44)), and haplotype G/A had a significant protective effect (p=2.25 x 10(-14)). None of the three SNPs showed significant differences between the EX and EG groups or between the PG and NG groups. CONCLUSIONS: These SNPs are associated with exfoliation syndrome/glaucoma in the Japanese population. The risk alleles in rs1048661 and rs2165241 are different from other populations. Additional genetic or environmental risk factors other than these LOXL1 SNPs could be associated with the development of exfoliation syndrome as well as exfoliation glaucoma among exfoliation syndrome patients.

HTRA1 promoter polymorphism predisposes Japanese to age-related macular degeneration.

PURPOSE: To study the effect of candidate single nucleotide polymorphisms (SNPs) on chromosome 10q26, recently shown to be associated with wet age-related macular degeneration (AMD) in Chinese and Caucasian cohorts, in a Japanese cohort. METHODS: Using genomic DNA isolated from peripheral blood of wet AMD cases and age-matched controls, we genotyped two SNPs, rs10490924, and rs11200638, on chromosome 10q26, 6.6 kb and 512 bp upstream of the HTRA1 gene, respectively, using temperature gradient capillary electrophoresis (TGCE) and direct sequencing. Association tests were performed for individual SNPs and jointly with SNP complement factor H (CFH) Y402H. RESULTS: The two SNPs, rs10490924 and rs11200638, are in complete linkage disequilibrium (D'=1). Previous sequence comparisons among seventeen species revealed that the genomic region containing rs11200638 was highly conserved while the region surrounding rs10490924 was not. The allelic association test for rs11200638 yielded a p-value <10(-11). SNP rs11200638 conferred disease risk in an autosomal recessive fashion: Odds ratio was 10.1 (95% CI 4.36, 23.06), adjusted for SNP CFH 402, for those carrying two copies of the risk allele, whereas indistinguishable from unity if carrying only one risk allele. CONCLUSIONS: The HTRA1 promoter polymorphism, rs11200638, is a strong candidate with a functional consequence that predisposes Japanese to develop neovascular AMD.

Complement factor H polymorphisms in Japanese population with age-related macular degeneration.

PURPOSE: To study the frequency of five haplotypes previously reported in the complement factor H (CFH) gene for Japanese patients with age-related macular degeneration (AMD). METHODS: Genomic DNA was isolated from peripheral blood samples taken from 96 Japanese AMD patients and 89 age-matched controls. All patients were diagnosed as having exudative (wet-type) AMD. The amplified polymerase chain reaction (PCR) products of CFH exons 2, 9, and 13, and intron 6 were analyzed by temperature gradient capillary electrophoresis (TGCE) and by direct sequencing. The haplotypes were identified, and their frequencies were calculated and compared with reported results. RESULTS: Five haplotypes were identified in the Japanese population including four already reported in the American population. The frequencies of these haplotypes were significantly different between Japanese and American in both control and case groups. The haplotype containing Y402H, which was previously reported to be associated with AMD, was only 4% in the control and case population, with a p value of 0.802. However, two other haplotypes were found as risk factors, which gave an increased likelihood of AMD of 1.9 and 2.5 fold (95% CI 1.12-3.69 and 1.42-6.38). One protective haplotype that decreased the likelihood of AMD by 1.6 fold (95% CI 0.26-0.67) was identified. CONCLUSIONS: The frequencies for five haplotypes previously identified were analyzed in a Japanese population with AMD. Four previously found haplotypes were identified and one additional haplotype was found. The frequencies of each haplotype were significantly different from that in found Americans affected with AMD. Two of the haplotypes were identified as risk factors and one was considered protective.

Binding of intimin with Tir on the bacterial surface is prerequisite for the barrier disruption induced by enteropathogenic Escherichia coli.

Enteropathogenic Escherichia coli (EPEC) infects intestinal epithelial cells and perturbs the intestinal barrier that limits the paracellular movement of molecules. The disruption of the barrier is mediated by the effectors translocated into the host cells through the bacterial type III secretion system (TTSS). A previous report has described the importance of a bacterial outer membrane protein, intimin, in EPEC-mediated disruption of the barrier, and proposed that intimin, in concert with a host intimin receptor, controls the activity of the translocated barrier-disrupting effectors [P. Dean, B. Kenny, Intestinal barrier dysfunction by enteropathogenic Escherichia coli is mediated by two effector molecules and a bacterial surface protein, Mol. Microbiol. 54 (2004) 665-675]. In this study, we found that the importance of intimin is in its ability to bind a bacterial intimin receptor, Tir. Additionally, the impaired ability of an intimin-negative mutant was not restored by co-infection with intimin-expressing TTSS mutants. Collectively, the results in this study favor an alternative scenario explaining the importance of intimin, that the binding of intimin with Tir on the bacterial surface triggers or promotes the translocation of factors required for the efficient disruption of the barrier. Thus, the interaction of intimin with Tir may serve as a molecular switch that controls the delivery of virulence factors into the host cells.

Isolation, gene expression and solution structure of a novel moricin analogue, antibacterial peptide from a lepidopteran insect, Spodoptera litura.

An antibacterial peptide was isolated from a lepidopteran insect, Spodoptera litura. The molecular mass of this peptide was determined to be 4489.55 by matrix assisted laser desorption/ionization-time of flight mass (MALDI-TOF MS) spectrometry. The peptide consists of 42 amino acids and the sequence has 69-98% identity to those of moricin-related peptides, antibacterial peptides from lepidopetran insects. Thus, the peptide was designated S. litura (Sl) moricin. Sl moricin showed a broad antibacterial spectrum against Gram-positive and negative bacteria. Sl moricin gene was inducible by bacterial injection and expressed tissue-specifically in the fat body and hemocytes. Furthermore, the solution structure of Sl moricin was determined by two-dimensional (2D) 1H-nuclear magnetic resonance (NMR) spectroscopy and hybrid distance geometry-simulated annealing calculation. The tertiary structure revealed a long alpha-helix containing eight turns along nearly the full length of the peptide like that of moricin, confirming that Sl moricin is a new moricin-like antibacterial peptide. These results suggest that moricin is present not only in B. mori but also in other lepidopteran insects forming a gene family.

Assessment of utility of meiosis-associated promoters of lily for induction of germinal ds transposition in transgenic rice.

In order to suppress the somatic excision of the Ds element and increase the independent transposition events of the Ac/Ds transposon tagging system in rice, we employed promoters of two meiosis-specific genes of lily, LIM10 and LIM18. The LIM10 promoter directed GUS expression specifically in anthers, with the LIM18 promoter doing the same in the anthers and somatic tissue. Both promoters induced independent germinal transposition with the frequency of approximately 1%. The LIM10 promoter, lacking induction of somatic transposition, is considered to be useful for improving transposon-tagging efficiencies in rice.

Isolation and characterization of a novel GRAS gene that regulates meiosis-associated gene expression.

GRAS protein is a family of plant-specific proteins that plays a role in various developmental processes. Here we report a novel GRAS protein from lily, designated LlSCL (Lilium longiflorum Scarecrow-like), dominantly expressed at the premeiotic phase within anthers. The LlSCL protein has two highly basic regions, and transient expression analyses of dissected GFP-LlSCL fusion proteins showed that both basic regions are important for the nuclear localization. A series of transcriptional activation experiments of truncated LlSCL proteins fused to the yeast GAL4 DNA-binding domain clearly demonstrated that the amino terminus of the LlSCL protein has a strong activity of transcriptional activation in the yeast as well as in the plant cell. Further investigation on the effect of the LlSCL protein on the transcriptional activity of the meiosis-associated promoter revealed that in pollen mother cells of the lily, the activity of the meiosis-associated promoter is specifically enhanced by LlSCL protein co-expression. These results suggest that LlSCL is involved in transcriptional regulation during microsporogenesis within the lily anther.

In vivo modifications of small GTPase Rac and Cdc42 by Bordetella dermonecrotic toxin.

Bordetella dermonecrotic toxin (DNT) is known to activate the small GTPase Rho through deamidation or polyamination. In this study, we examined whether Rac and Cdc42, the two other members of the Rho family, serve as intracellular targets for the toxin. Immunoprecipitation and immunoblot assays revealed that DNT deamidated or polyaminated intracellular Rac and Cdc42. After the modifications, both Rac and Cdc42 lost their GTP-hydrolyzing, but not GTP-binding, activities. The interactions of the modified Rac and Cdc42 with their respective effectors were strictly dependent on GTP. MC3T3-E1 cells treated with DNT at high concentrations demonstrated extensive formations of lamellipodia and filopodia, which indicate the intracellular activation of Rac and Cdc42, respectively.