Human cortical interneurons optimized for grafting specifically integrate, abort seizures, and display prolonged efficacy without over-inhibition

Previously, we demonstrated the efficacy of human pluripotent stem cell (hPSC)-derived GABAergic cortical interneuron (cIN) grafts in ameliorating seizures. However, a safe and reliable clinical translation requires a mechanistic understanding of graft function, as well as the assurance of long-term efficacy and safety. By employing hPSC-derived chemically matured migratory cINs in two models of epilepsy, we demonstrate lasting efficacy in treating seizures and comorbid deficits, as well as safety without uncontrolled growth. Host inhibition does not increase with increasing grafted cIN densities, assuring their safety without the risk of over-inhibition. Furthermore, their closed-loop optogenetic activation aborted seizure activity, revealing mechanisms of graft-mediated seizure control and allowing graft modulation for optimal translation. Monosynaptic tracing shows their extensive and specific synaptic connections with host neurons, resembling developmental connection specificity. These results offer confidence in stem cell-based therapy for epilepsy as a safe and reliable treatment for patients suffering from intractable epilepsy.

Impact of schizophrenia GWAS loci converge onto distinct pathways in cortical interneurons vs glutamatergic neurons during development

Remarkable advances have been made in schizophrenia (SCZ) GWAS, but gleaning biological insight from these loci is challenging. Genetic influences on gene expression (e.g., eQTLs) are cell type-specific, but most studies that attempt to clarify GWAS loci's influence on gene expression have employed tissues with mixed cell compositions that can obscure cell-specific effects. Furthermore, enriched SCZ heritability in the fetal brain underscores the need to study the impact of SCZ risk loci in specific developing neurons. MGE-derived cortical interneurons (cINs) are consistently affected in SCZ brains and show enriched SCZ heritability in human fetal brains. We identified SCZ GWAS risk genes that are dysregulated in iPSC-derived homogeneous populations of developing SCZ cINs. These SCZ GWAS loci differential expression (DE) genes converge on the PKC pathway. Their disruption results in PKC hyperactivity in developing cINs, leading to arborization deficits. We show that the fine-mapped GWAS locus in the ATP2A2 gene of the PKC pathway harbors enhancer marks by ATACseq and ChIPseq, and regulates ATP2A2 expression. We also generated developing glutamatergic neurons (GNs), another population with enriched SCZ heritability, and confirmed their functionality after transplantation into the mouse brain. Then, we identified SCZ GWAS risk genes that are dysregulated in developing SCZ GNs. GN-specific SCZ GWAS loci DE genes converge on the ion transporter pathway, distinct from those for cINs. Disruption of the pathway gene CACNA1D resulted in deficits of Ca2+ currents in developing GNs, suggesting compromised neuronal function by GWAS loci pathway deficits during development. This study allows us to identify cell type-specific and developmental stage-specific mechanisms of SCZ risk gene function, and may aid in identifying mechanism-based novel therapeutic targets.

Neurofibromin Deficiency Causes Epidermal Growth Factor Receptor Upregulation through the Activation of Ras/ERK/SP1 Signaling Pathway in Neurofibromatosis Type 1-Associated Malignant Peripheral Nerve Sheet Tumor

Neurofibromatosis type 1 (NF1) is an autosomal dominant human genetic disorder. The progression of benign plexiform neurofibromas to malignant peripheral nerve sheet tumors (MPNSTs) is a major cause of mortality in patients with NF1. Although elevated epidermal growth factor receptor (EGFR) expression plays a crucial role in the pathogenesis of MPNST, the cause of EGFR overexpression remains unclear. Here, we assessed EGFR expression levels in MPNST tissues of NF1 patients and NF1 patient-derived MPNST cells. We found that the expression of EGFR was upregulated in MPNST tissues and MPNST cells, while the expression of neurofibromin was significantly decreased. Manipulation of NF1 expression by NF1 siRNA treatment or NF1-GAP-related domain overexpression demonstrated that EGFR expression levels were closely and inversely correlated with neurofibromin levels. Notably, knockdown of the NF1 gene by siRNA treatment augmented the nuclear localization of phosphorylated SP1 (pSP1) and enhanced pSP1 binding to the EGFR gene promoter region. Our results suggest that neurofibromin deficiency in NF1-associated MPNSTs enhances the Ras/ERK/SP1 signaling pathway, which in turn may lead to the upregulation of EGFR expression. This study provides insight into the progression of benign tumors and novel therapeutic approaches for treatment of NF1-associated MPNSTs.

Effect of feeding corn distillers dried grains with solubles naturally contaminated with deoxynivalenol on growth performance, meat quality, intestinal permeability, and utilization of energy and nutrients in broiler chickens

The objective of this experiment was to investigate the effect of feeding corn distillers dried grains with solubles (DDGS) naturally contaminated with deoxynivalenol (DON) on growth performance, meat quality, intestinal permeability, and utilization of energy and nutrients in broiler chickens. Two trials (growth and metabolism trials) were conducted. In the growth trial, a total of four hundred 7-day-old Ross 308 broiler chicks were allotted to 1 of 5 dietary treatments with 8 replicates in a completely randomized design. The diets were formulated to contain 5 inclusion levels of 0, 5, 10, 15, or 20% DON-contaminated DDGS in diets and were fed to birds for 21 d. Results indicated that increasing inclusion levels of DON-contaminated DDGS decreased (linear, P < 0.01) BW gain and feed efficiency of broiler chickens. The relative organ weights of the liver and breast were decreased (linear and quadratic, P < 0.05) by increasing inclusion levels of DON-contaminated DDGS in diets. The transepithelial electrical resistance values as a measure of intestinal permeability were decreased (linear, P < 0.05) by increasing inclusion levels of DON-contaminated DDGS in diets. In the metabolism trial, a total of twenty four 22-day-old Ross 308 broiler chickens were allotted to 1 of 3 dietary treatments consisting of 0, 10, or 20% inclusion of DON-contaminated DDGS in diets. Each treatment had 8 replicates. Increasing inclusion levels of DON-contaminated DDGS in diets decreased (linear and quadratic, P < 0.05) ME_n (AME_n and TME_n) and apparent total tract retention of nitrogen and acid-hydrolyzed ether extract in diets. In conclusion, feeding diets containing more than 10% DON-contaminated DDGS to broiler chickens has negative effects on growth performance, intestinal permeability, and utilization of energy and nutrients in diets. Therefore, it is suggested that if DDGS is contaminated with DON, inclusion level of DDGS should be limited, possibly at less than 5.0% in broiler diets.

Marine cyanobacterium Spirulina maxima as an alternate to the animal cell culture medium supplement

Serum is a stable medium supplement for in vitro cell culture. Live cells are used in stem cell research, drug toxicity and safety testing, disease diagnosis and prevention, and development of antibiotics, drugs, and vaccines. However, use of serum in culture involves concerns such as an ethical debate regarding the collection process, lack of standardized ingredients, and high cost. Herein, therefore, we evaluated the possibility of using edible cyanobacterium (Spirulina maxima), which is a nutrient-rich, sustainable, and ethically acceptable source, as a novel substitute for fetal bovine serum (FBS). H460 cells were cultured to the 10th generation by adding a mixture of spirulina animal cell culture solution (SACCS) and FBS to the culture medium. Cell morphology and viability, cell cycle, apoptosis, proteomes, and transcriptomes were assessed. We observed that SACCS had better growth-promoting capabilities than FBS. Cell proliferation was promoted even when FBS was replaced by 50-70% SACCS; there was no significant difference in cell shape or viability. There were only slight differences in the cell cycle, apoptosis, proteomes, and transcriptomes of the cells grown in presence of SACCS. Therefore, SACCS has the potential to be an effective, low-cost, and eco-friendly alternative to FBS in in vitro culture.

Effect of stocking density and dietary tryptophan on growth performance and intestinal barrier function in broiler chickens

The objective of the present experiment was to investigate the effect of stocking density (SD) and dietary supplementation of crystalline tryptophan (Trp) on growth performance and intestinal barrier function in broiler chickens raised in a floor pen. The experiment was conducted using a completely randomized design with a 2 × 2 factorial arrangement consisting of 2 different SD and 2 supplemental levels of dietary Trp. A total of 1,140 Ross 308 broiler chickens at 21 d of age were allotted to 1 of 4 treatments with 5 replicates. Low SD (9 birds/m2) and high SD (18 birds/m2) were achieved by raising different number of birds per identical floor pen (2.0 m × 2.4 m). The basal diet was formulated with no supplemental Trp in diets to meet or exceed nutrient recommendation of the Ross 308 manual. The calculated concentrations of total Trp and digestible Trp in the basal diet were 0.19 and 0.16%, respectively. The other diet was prepared by adding 0.16% crystalline Trp to the basal diet. Diets were fed to birds for 21 d. At the end of the experiment, 2 birds per replicate were euthanized to collect tissue samples for further analyses. Results indicated that there were no interactions between SD and dietary Trp for all measurements. For the main effects, birds raised at a low SD had greater (P < 0.01) body weight gain, feed intake, and feed efficiency than those raised at a high SD. However, supplementation of dietary Trp had no effect on broiler performance. Furthermore, there were no main effects of SD and dietary Trp on intestinal barrier functions. In conclusion, broiler chickens raised in a floor pen with a high SD (18 birds/m2) have decreased growth performance with little changes in intestinal barrier functions. Supplementation of dietary Trp at 0.16% has no positive effect on broiler chickens raised in a floor pen with either a low or high SD.

Effect of dietary melamine concentrations on growth performance, excreta characteristics, plasma measurements, and melamine residue in the tissue of male and female broiler chickens

The objectives of the current experiment were to investigate the effect of dietary melamine concentrations on growth performance, excreta characteristics, plasma measurements, and melamine residue in the tissue of male and female broiler chickens. Finally, the safe levels of melamine in broiler diets were determined based on BW gain (BWG) and melamine residue in the breast meat. A total of 1,008 1-d-old Ross 308 male and female broiler chickens were allotted to 1 of 7 dietary treatments within each sex in a completely randomized design. There were 6 replicates per treatment and each replicate consisted of 12 birds. Dietary melamine concentrations were set to 0; 250; 500; 750; 1,000; 5,000; or 10,000 mg/kg by adding a purified form of melamine. Diets were provided to birds on ad libitum basis for 35 d. Results indicated that no significant interaction between sex and dietary melamine concentrations was observed for all measurements. The BW, BWG, and feed intake for birds fed diets containing 10,000 mg/kg melamine were less (P < 0.05) than for those fed other diets. Melamine residues in the kidney and breast for birds fed diets containing 10,000 mg/kg melamine were greater (P < 0.05) than for birds fed other diets. The toxic level of dietary melamine based on BWG was determined by the one-slope broken-line analysis. The resulting equation was Y = 1,851 - 0.0404 × (X - 4,292), which indicated that a greater than 4,292 mg/kg melamine in diets was toxic to broiler chickens. The safe level of dietary melamine to limit melamine residue in the broiler breast was analyzed using the linear regression, which indicated that the safe level of melamine in broiler diets was 814 mg/kg. In conclusion, less than 814 mg/kg melamine in broiler diets should be maintained to satisfy human food safety regulations for melamine residue in the breast meat of broiler chickens.

Effect of stocking density and sex on growth performance, meat quality, and intestinal barrier function in broiler chickens

The objective of the current experiment was to investigate the effect of stocking density and sex on growth performance, meat quality, and intestinal barrier function in broiler chickens. The experiment was conducted in a completely randomized design with a 2 × 4 factorial arrangement consisting of sex and four different stocking densities in battery cages. A total of 540 1-d-old Ross 308 broiler chickens were allotted to one of eight treatments with five replicates. Within each sex, birds were raised at four different stocking densities of 15.2, 20.2, 25.3, or 30.4 birds/m2 from 1 to 28 d of age. Different stocking densities were achieved by raising a different number of birds per battery cage with identical floor size (0.76 m × 0.78 m). At the end of the experiment, two birds per replicate were euthanized by CO2 asphyxiation to collect tissue samples for further analyses. Results indicated that no interactions between sex and stocking density were observed for all measurements except for serum lipopolysaccharide (LPS) concentrations. Increasing stocking density decreased (linear, P < 0.01) body weight gain and feed intake, but had no negative effects on meat quality. Trans-epithelial electrical resistance values, a measure of intestinal permeability, were decreased (linear, P < 0.01) with increasing stocking density, regardless of sex. Accordingly, serum LPS concentrations were increased (linear, P < 0.01) with increasing stocking density. However, increasing stocking density increased serum LPS concentrations in male broiler chickens, but had no effects on female broiler chickens, showing an interaction (P < 0.01). The expression of zonula occludens-1 (ZO-1) and junctional adhesion molecule B (JAM-2) was decreased (linear, P < 0.05) with increasing stocking density. In conclusion, increasing stocking density decreases broiler performance regardless of sex and this negative effect is likely associated with decreased intestinal barrier function.

Draft genome of agar-degrading marine bacterium Gilvimarinus agarilyticus JEA5

Gilvimarinus agarilyticus JEA5, which effectively degrades agar, was isolated from the seawater of Jeju Island, Republic of Korea. Here, we report the draft genome sequence of G. agarilyticus JEA5 with a total genome size of 4,179,438bp from 2 scaffolds (21 contigs) with 53.15% G+C content. Various polysaccharidases including 11 predicted agarases were observed from the draft genome of G. agarilyticus JEA5.

TAGLN expression is upregulated in NF1-associated malignant peripheral nerve sheath tumors by hypomethylation in its promoter and subpromoter regions

Neurofibromatosis type 1 (NF1) caused by NF1 gene mutation is a commonly inherited autosomal dominant disorder. Malignant peripheral nerve sheath tumors (MPNSTs), a type of aggressive sarcoma, are a major cause of mortality in NF1 patients. The malignant transformation of benign plexiform neurofibromas (PNs) to MPNSTs is a marked peculiarity in NF1 patients, yet the pathogenesis remains poorly understood. We found that an actin-associated protein transgelin (SM22) was highly expressed in NF1-deficient MPNST tissues compared to NF1-deficient PN tissues using immunohistological staining and primary cultured MPNST cells in western blot analysis. We further found that this transgelin upregulation was caused by increased transcriptional expression of the TAGLN gene encoding transgelin. Comparison of DNA methylation values in the promoter and subpromoter regions of the TAGLN gene in three types of NF1-deficient primary-cultured cells, derived from an NF1 patient's normal phenotype, a benign PN and MPNST tissues, revealed that the TAGLN gene was hypomethylated in the MPNST cells. Next, to determine the functional role of transgelin in MPNST pathogenesis, we manipulated the TAGLN gene expression and investigated the alteration of the RAS-mitogen-activated protein kinase (MAPK) signaling pathway in the normal-phenotypic and malignant tumor cells. The downregulation of TAGLN expression in NF1-deficient MPNST tumor cells through the treatment of the small interfering RNA resulted in a decrease in the RAS activation (GTP-RAS) and the downstream ERK1/2 activation (phosphorylated ERK1/2), while the overexpression of TAGLN in normal-phenotypic NF1-deficient cells caused an increase in RAS and ERK1/2 activation. These results indicate that upregulation of transgelin caused by hypomethylation of the TAGLN gene is closely involved in tumor progression in NF1.

Investigation of papulopustular eruptions caused by cetuximab treatment shows altered differentiation markers and increases in inflammatory cytokines

BACKGROUND

Epidermal growth factor receptor (EGFR) critically regulates tumour cell division, survival and metastasis. Agents that inhibit EGFR have been used in the treatment of advanced-stage malignancies, but cause variable cutaneous side-effects, most often papulopustular eruptions and xerosis.

OBJECTIVES

We assayed expression of inflammatory cytokines [interleukin (IL)-1alpha, tumour necrosis factor (TNF)-alpha, interferon (IFN)-gamma, human leucocyte antigen (HLA)-DR and intercellular adhesion molecule (ICAM)-1], differentiation markers (filaggrin, involucrin and loricrin) and phosphorylated EGFRs (pEGFRs) in papulopustular eruptions to determine the association between these markers and the eruptions caused by cetuximab.

PATIENTS/METHODS

Twelve papulopustular lesion biopsies were selected from patients with colon cancer who had received cetuximab treatment. Immunohistochemistry and immunofluorescence with a confocal laser scanning microscopy were performed.

RESULTS

Filaggrin expression decreased and expression of involucrin, various inflammatory markers (IL-1alpha, TNF-alpha, ICAM-1 and HLA-DR) increased and the expression of pEGFR was markedly downregulated in papulopustular eruptions. In perilesions, decreased pEGFR expression was noted in hair follicles compared with interfollicular epidermis. The increase of IL-1alpha and TNF-alpha was observed in perilesions as in the lesions.

CONCLUSIONS

The early inflammatory events (IL-1alpha and TNF-alpha expression) seen, and the lack of pEGFR in perilesional follicles, indicate that inflammatory events induced by EGFR inhibition may initiate papulopustular eruptions along with the altered differentiations. The decrease of filaggrin may contribute to the pathogenesis of the xerosis caused by cetuximab.

A Ubiquitous Chronic Disease Care system using cellular phones and the internet

AIMS

The rapidly increasing prevalence of chronic diseases is an important challenge to healthcare systems worldwide. To improve the quality and efficiency of chronic disease care, we investigated the effectiveness and applicability of the Ubiquitous Chronic Disease Care (UCDC) system using cellular phones and the internet for overweight patients with both Type 2 diabetes and hypertension.

METHODS

We conducted a randomized, controlled clinical trial over 3 months that included 123 patients at a university hospital and a community public health centre.

RESULTS

After 12 weeks, there were significant improvements in HbA(1c) in the intervention group (7.6 +/- 0.9% to 7.1 +/- 0.8%, P < 0.001) compared with the control group (7.4 +/- 0.9% to 7.6 +/- 1.0%, P = 0.03). Furthermore, we observed a significant reduction in systolic and diastolic blood pressure, as well as improvements in total cholesterol, low-density lipoprotein-cholesterol and triglyceride levels in the intervention group. Furthermore, there was a significant increase in adiponectin levels in the intervention group compared with the control group, although high-sensitivity C-reactive protein and interleukin-6 levels did not change in either group.

CONCLUSIONS

The novel UCDC system presented in this paper improved multiple metabolic parameters simultaneously in overweight patients with both Type 2 diabetes and hypertension.

Portable microscopic cell counter for the determination of residual leucocytes in blood components

BACKGROUND AND OBJECTIVES

The accurate determination of residual white blood cell (WBC) in blood components is of considerable clinical importance, and a variety of methods have been devised for the counting of low levels of residual WBC. In this study, we evaluated the performance of microscopic cell counter with microchannel plastic chip (C-reader) with regard to its ability to quantify WBC in WBC-reduced red cell concentrates.

MATERIALS AND METHODS

In order to quantify residual WBC with the microscopic cell counter, WBC-reduced red cell concentrate was stained using propidium iodide. Three studies were performed: linearity, precision and correlation compared to those of manual Nageotte chamber counting and automatic flow cytometric methods.

RESULTS

Dilution experiments, conducted over a range of 0.7-712 WBC/microl, showed a linearity of r(2) > 0.999, with coefficient of variation values of < or = 15.6% and accuracy of 93.8% over all tested ranges. In comparison with the Nageotte chamber counting and flow cytometric methods, the correlation coefficients were r(2) > 0.995. The detection limit of this method was 0.24 WBC/microl. Total analysis time per sample was approximately 5 min.

CONCLUSION

The microscopic cell counter for residual WBC counting was determined to be efficient at the level of currently defined standards, with acceptable precision and accuracy. This method may prove useful for the quality assurance and control of WBC-depleted blood products.

Stimulation of human DNA topoisomerase II activity by its direct association with the beta subunit of protein kinase CKII

DNA topoisomerase II copurifies with and is phosphorylated by protein kinase CKII. In this study, a yeast two-hybrid system was used to investigate the interaction between human topoisomerase II isozymes and CKII subunits. The two-hybrid test clearly showed that both topoisomerase IIalpha and IIbeta interact with the CKIIbeta, but not the CKIIalpha subunit. The two-hybrid test also demonstrated that topoisomerase IIbeta residues 1099-1263 and topoisomerase IIalpha residues 1078-1182 mediate the interaction with the CKIIbeta subunit, providing evidence that the leucine zipper motif and the major CKII-dependent phosphorylation sites of topoisomerase II are unnecessary for its physical binding to CKIIbeta. Furthermore, a DNA relaxation assay demonstrated that the CKII subunit enhances topoisomerase II activity by physical interaction with topoisomerase II.

Inhibitory mechanism of pinacidil on catecholamine secretion from the rat perfused adrenal gland evoked by cholinergic stimulation and membrane depolarization

1. The present study attempted to investigate the effect of potassium channel openers on secretion of catecholamines (CA) evoked by cholinergic stimulation and membrane depolarization from rat isolated perfused adrenal gland. 2. The perfusion of pinacidil (30-300 microM) into an adrenal vein for 20 min produced dose-dependent inhibition of CA secretion evoked by acetylcholine (ACh; 5.32 mM), high K+ (56 mM), 1,1-dimethyl-4-phenylpiperazinium iodide (DMPP; 100 microM for 2 min), 3-(m-chloro-phenyl-carbamoyl-oxy)-2-butynyl trimethyl ammonium chloride (McN-A-343; 100 microM for 2 min), cyclopiazonic acid (CPA; 10 microM for 4 min) and methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoromethylphenyl)-pyri dine-5-carboxylate (Bay-K-8644; 10 microM for 4 min). 3. In the presence of minoxidil (100 microM), which is also known to be a potassium channel activator, CA secretory responses evoked by ACh, high potassium, DMPP, McN-A-343, Bay-K-8644 and CPA were also significantly depressed. 4. In adrenal glands preloaded with pinacidil (100 microM) in the presence of glibenclamide (GB; 1 microM), a specific blocker of ATP-regulated potassium channels, CA secretory responses evoked by ACh, high potassium, DMPP, McN-A-343, Bay-K-8644 and CPA were restored to a considerable extent of the control release as compared with that of pinacidil only. 5. These results suggest that pinacidil causes marked inhibition of CA secretion evoked by stimulation of cholinergic (both nicotinic and muscarinic) receptors, as well as by membrane depolarization, indicating that this effect may be mediated by inhibiting influx of extracellular calcium and release of intracellular calcium in the rat adrenomedullary chromaffin cells. Furthermore, these findings suggest that these potassium channel opener-sensitive membrane potassium channels also play a modulatory role in regulating CA secretion.

Inhibitory effect of arginine-derivatives from ginseng extract and basic amino acids on protein-arginine N-methyltransferase

Protein-arginine N-methyltransferase (protein methylase I) catalyzes methylation of arginyl residues on substrate protein posttranslationally utilizing S-adenosyl-L-methionine as the methyl donor and yields NG-methylarginine residues. Arginyl-fructose and arginyl-fructosyl-glucose from Korean red ginseng were found to inhibit protein methylase I activity in vitro. This inhibitory activity was shown to be due to arginyl moiety in the molecules, rather than that of carbohydrates. Several basic amino acids as well as polyamines were also found to inhibit protein methylase I activity. Interestingly, the intensity of the inhibitory activity was correlated with the number of amino-group in polyamines, thus, in the order of spermine > spermidine > putrescine > agmatine-sulfate, with IC50 at approximately 15 mM, 25 mM, 35 mM, and 50 mM, respectively. On the other hand, neutral amino acids or NaCl did not inhibit the enzyme activity. Lineweaver-Burk plot analysis of the protein methylase I activity in the presence of arginine and spermidine indicated that the inhibition was competitive in nature in respect to protein substrate, with the Ki values of 24.8 mM and 11.5 mM, respectively.

Identification of highly methylated arginine residues in an endogenous 20-kDa polypeptide in cancer cells

Enzymatic methylation of endogenous proteins in several cancer cell lines was investigated to understand a possible relationship between protein-arginine methylation and cellular proliferation. Cytosolic extracts prepared from several cancer cells (HeLa, HCT-48, A549, and HepG2) and incubated with S-adenosyl-L-[methyl-3H]methionine revealed an intensely [methyl-3H]-labeled 20-kDa polypeptide. On the other hand, cytosolic extracts prepared from normal colon cells did not show any methylation of the 20-kDa protein under identical conditions. To identify nature of the 20-kDa polypeptide, purified histones were methylated with HCT-48 cytosolic extracts and analyzed by SDS-PAGE. However, none of the histones comigrated with the methylated 20-kDa polypeptide, indicating that it is unlikely to be any of the histone subclasses. The [methyl-3H]group in the 20-kDa polypeptide was stable at pH 10-11 (37 degrees C for 30 min) and methylation was not stimulated by GTPgammaS (4 mM), thus the reaction is neither carboxyl methylesterification on isoaspartyl residues, nor on C-terminal farnesylated cysteine. The present study together with the previous identification of N(G)-methylated arginine residues in the HCT-48 cytosol fraction suggests that this novel endogenous 20-kDa arginine-methylation is a cellular proliferation-related posttranslational modification reaction.

Selection of RAPD marker for growth of seedlings at low temperature in rice

We have developed a polymerase chain reaction (PCR)-based assay that could effectively reduce the time period required to screen and select the cold tolerance gene of rice seedlings under field conditions. The two specific random amplified polymorphic DNA (RAPD) fragments for the assay were identified on the basis of quantitative trait loci (QTL) analysis which were found to be tightly linked to cold sensitivity. The two RAPD fragments, OPT8(600) in the cold sensitivity rice cultivar 'Dular (indica)' and OPU20(1200) in the resistance rice cultivar 'Toyohatamochi (japonica)', were identified after screening 11 RAPD fragments using 2 random primers on the genomic DNAs of 'Dular' and 'Toyohatamochi'. These primers, when used in a multiplexed PCR, specifically amplified a 0.6 kb and a 1.2 kb fragment in the sensitive and resistant rice cultivars, respectively. When this assay was performed on the genomic DNAs of 16 japonica, 3 Tongil (indica/ japonica), and 2 indica rice cultivars, the primers amplified a 0.6 kb fragment in all of the cold sensitivity rice cultivars or 1.2 kb fragment in all of the resistance ones. These markers can be of potential use in the marker-assisted selection (MAS) for cold tolerance in rice seedling. As screening for resistance can now be conducted independent of the availability of low temperature, the breeding of cold tolerance cultivars can be hastened.

Recent advances in protein methylation: enzymatic methylation of nucleic acid binding proteins

Heterogeneous nuclear RNP protein A1, one of the major proteins in hnRNP particle (precursor for mRNA), is known to be posttranslationally arginine-methylated in vivo on residues 193, 205, 217 and 224 within the RGG box, the motif postulated to be an RNA binding domain. Possible effect of NG-arginine methyl-modification in the interaction of protein A1 to nucleic acid was investigated. The recombinant hnRNP protein A1 was in vitro methylated by the purified nuclear protein/histone-specific protein methylase I (S-adenosylmethionine:protein-arginine N-methyltransferase) stoichiometrically and the relative binding affinity of the methylated and the unmethylated protein A1 to nucleic acid was compared: Differences in their binding properties to ssDNA-cellulose, pI values and trypsin sensitivities in the presence and absence of MS2-RNA all indicate that the binding property of hnRNP protein A1 to single-stranded nucleic acid has been significantly reduced subsequent to the methylation. These results suggest that posttranslational methyl group insertion to the arginine residue reduces protein-RNA interaction, perhaps due to interference of H-bonding between guanidino nitrogen arginine and phosphate RNA.

Partial purification of protein farnesyl cysteine carboxyl methyltransferase from bovine brain

C-terminal farnesyl cysteine carboxyl methylation has been known to be the last step in the post-translational modification processes of several important signal transduction proteins in eukaryotes including ras related GTP binding proteins and the gamma-subunit of heterotrimeric G proteins. Protein farnesyl cysteine carboxyl methyltransferase (PFCCMT; EC, 2.1.1.100) catalyzing the reaction is well characterized as being stimulated by guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) and suppressed by N-acetyl-S-farnesyl-L-cysteine (AFC). As an initial step to understand the physiological significance of the process, we attempted to purify the enzyme, which was partially purified 130-fold (specific activity, 143 pmol of methyl group transferred/min/mg of protein) with yield of 1.8% after purification by fast protein liquid chromatography (FPLC) on a Superdex 75 column. The enzyme was further purified with non denaturing polyacrylamide gel electrophoresis (ND-PAGE) and sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The molecular weight of PFCCMT was determined to be about 30 kDa based on Superdex 75 FPLC as well as photoaffinity labelling with S-adenosyl-L-[methyl-3H] methionine ([methyl-3H]SAM). The partially purified enzyme (Superdex 75 eluate) was found to be characteristically affected by GTP gamma S, being activated about 40-fold in 2 mM, in contrast to ATP which did not show any effect on enzyme activity. Meanwhile, the enzyme was found to be markedly inhibited by AFC, reaching 0 activity in 2 mM. These observations strongly suggested that the partially purified enzyme was PFCCMT.

Selective Sp1 binding is critical for maximal activity of the human c-kit promoter

The receptor tyrosine kinase c-kit is necessary for normal hematopoiesis, the development of germ cells and melanocytes, and the pathogenesis of certain hematologic and nonhematologic malignancies. To better understand the regulation of the c-kit gene, a detailed analysis of the core promoter was performed. Rapid amplification of cDNA ends (RACE) and RNase protection methods showed two major transcriptional initiation sites. Luciferase reporter assays using 5' promoter deletion-reporter constructs containing up to 3 kb of 5' sequence were performed in hematopoietic and small-cell lung cancer cell lines which either did or did not express the endogenous c-kit gene. This analysis showed the region 83 to 124 bp upstream of the 5' transcription initiation site was crucial for maximal core promoter activity. Sequence analysis showed several potential Sp1 binding sites within this highly GC-rich region. Gel shift and DNase footprinting showed that Sp1 selectively bound to a single site within this region. Supershift studies using an anti-Sp1 antibody confirmed specific Sp1 binding. Site-directed mutagenesis of the -93/-84 Sp1 binding site reduced promoter-reporter activity to basal levels in c-kit-expressing cells. Cotransfection into Drosophila SL2 cells of a c-kit promoter-reporter construct with an Sp1 expression vector showed an Sp1 dose-dependent enhancement of expression that was markedly attenuated by mutation of the -93/-84 site. These results indicate that despite the fact that the human c-kit promoter contains multiple potential Sp1 sites, Sp1 binding is a selective process that is essential for core promoter activity.

Identification of protein-arginine N-methyltransferase as 10-formyltetrahydrofolate dehydrogenase

S-Adenosylmethionine:protein-arginine N-methyltransferase (EC 2.1.1. 23; protein methylase I) transfers the methyl group of S-adenosyl-L-methionine to an arginine residue of a protein substrate. The homogeneous liver protein methylase I was subjected to tryptic digestion followed by reverse phase high performance liquid chromatography (HPLC) separation and either "on-line" mass spectrometric fragmentation or "off-line" Edman sequencing of selected fractions. Data base searching of both the mass spectrometric and Edman sequencing data from several peptides identified the protein methylase as 10-formyltetrahydrofolate dehydrogenase (EC 1.5.1.6; Cook, R. J., Lloyd, R. S., and Wagner, C. (1991) J. Biol. Chem. 266, 4965-4973; Swiss accession number). This identification was confirmed by comparative HPLC tryptic peptide mapping and affinity chromatography of the methylase on the 5-formyltetrahydrofolate-Sepharose affinity gel used to purify the dehydrogenase. The purified rat liver methylase had approximately 33% of the 10-formyltetrahydrofolate dehydrogenase and 36% of the aldehyde dehydrogenase activity as compared with the recombinant dehydrogenase, which also had protein methylase I activity. Polyclonal antibodies against recombinant dehydrogenase reacted with protein methylase I purified either by polyacrylamide gel electrophoresis or 5-formyltetrahydrofolate affinity chromatography. In each instance there was only a single immunoreactive band at a molecular weight of approximately 106,000. Together, these results confirm the co-identity of protein-arginine methyltransferase and 10-formyltetrahydrofolate dehydrogenase.

Heterogeneous nuclear RNP protein A1-arginine methylation during HCT-48 cell cycle

Protein methylase I (protein-arginine N-methyltransferase) was examined in HCT-48 cells, synchronized by serum deprivation and hydroxyurea treatment. The enzyme activity to methylate the added hnRNP protein A1 increased about 2-fold from G0 to S phase, and then decreased during G2/M phase. The enzymatically [methyl-3H]-labeled hnRNP protein A1 was identified by SDS-PAGE/fluorography, and the products were identified as NG-monomethylarginine and NG,NG-dimethyl-(asymmetric)arginines by HPLC. Among endogenous proteins, the 20-kDa species in the extract was most intensely [methyl-3H]-labeled. This 20-kDa methylation was markedly inhibited by the addition of exogenous hnRNP protein A1, indicating that these two substrates compete for the same protein methylase. The possible role of this post-translational modification has been discussed.

Biological methylation of myelin basic protein: enzymology and biological significance

Myelin is a membrane characteristic of the nervous tissue and functions as an insulator to increase the velocity of the stimuli being transmitted between a nerve cell body and its target. Myelin isolated from human and bovine nervous tissue is composed of approximately 80% lipid and 20% protein, and 30% of the protein fraction constitutes myelin basic protein (MBP). MBP has an unusual amino acid at Res-107 as a mixture of NG-monomethylarginine and NG, N'G-dimethylarginine. The formation of these methylarginine derivatives is catalysed by one of the subtypes of protein methylase I, which specifically methylates Res-107 of this protein. Evidence is presented to demonstrate an involvement of this biological methylation in the integrity and maintenance of myelin.

Effect of rifampin on the plasma concentration and the clinical effect of haloperidol concomitantly administered to schizophrenic patients

We assessed the changes of plasma haloperidol concentrations and clinical responses repeatedly up to 4 weeks after coadministration or discontinuation of rifampin in 12 schizophrenic patients taking haloperidol alone (group I) and 5 patients taking haloperidol and antituberculotic drugs (group II). After coadministration of rifampin in group I, daily trough haloperidol concentrations rapidly decreased and reached 63% of baseline level by day 3, 41.3% by day 7, and 30% by day 28. On the other hand, after discontinuation of rifampin in group II, plasma haloperidol concentration increased to 140.7% of baseline level by day 3, 228.7% by day 7, and 329% by day 28. In this study, a 30% or greater change in the clinical rating scale was considered a positive clinical response of the drug interaction. Using this criterion, 50% of the group I subjects responded according to the Brief Psychiatric Rating Scale (BPRS) total score, and 25% responded according to the BPRS subscale for psychiatric symptoms. No positive responses were observed in group II patients. These results strongly suggest that rifampin interacts with the clinical effects as well as the plasma concentrations of coadministered haloperidol, and careful monitoring should be considered when coadministration or discontinuation of rifampin is needed in a schizophrenic patient taking haloperidol.

Neural-net computing for interpretation of semiconductor film optical ellipsometry parameters

Optical ellipsometry has been found to be a promising technique for monitoring process parameters, such as film composition and film thickness, of semiconductor wafers grown with molecular beam epitaxy. Whereas it is a straightforward task to calculate ellipsometry angles given the thickness of the film and the refractive indexes of the film and substrate, it is a difficult task to invert that mathematical relationship. However, the process must be inverted if the measured parameters are to be interpreted meaningfully in terms of film composition and film thickness. This paper reports on the use of neural-net computing for the inverse mapping of measured ellipsometry parameters. We used a functional-link net which is very efficient in function approximation. The advantage of using the net, however, is not only its speed, but also because some other net architecture characteristics allow us to perform the task in a holistic manner.

Genes for insulin-like growth factors I and II are expressed in senescent rat tissues

Insulin-like growth factor IGF-I and IGF-II gene expression was measured for the first time in rat liver, brain and heart during the later stages of life, i.e., young adulthood (6 months) to senescence (25 months). IGF-I mRNA was detected in all three tissues at all ages. Its relative level decreased the most in the liver with advancing age. IGF-II mRNA was detected in the brain and heart but not the liver at all ages. The level of IGF-II mRNA decreased only slightly in the brain from young adulthood to senescence.

RNA synthesis by nuclei and chromatin isolated from adult and senescent Wistar rat liver

Nuclei isolated from senescent (22-26 months) female Wistar rat liver show a decreased RNA synthesis compared to nuclei from adult (12 months) liver. Kinetic analyses demonstrate a decreased rate (25-42%) and maximal incorporation (41-54%) of labeled uridine triphosphate into both rRNA and mRNA in senescent nuclei. Chromatin-bound RNA polymerase activity is decreased by 36%, whereas free RNA polymerase activity, i.e., not bound to chromatin, is increased by 41% in senescent nuclei, but the total bound plus free activity is the same in senescent and adult nuclei. Isolated senescent chromatin shows reduced transcriptional capacity and requires a higher temperature to initiate melting. A decreased ability of chromatin to bind RNA polymerases appears to underlie the observed decreased RNA synthesis in senescent liver nuclei.

RNA synthesis by hepatocytes isolated from adult and senescent Wistar rat liver

The rates of synthesis of total RNA, poly(A)+ RNA and poly(A)+ RNA are decreased by 41, 49 and 42%, respectively, in hepatocytes isolated from senescent (25 months) compared to adult (12 months) female Wistar rats. Results from transcription run-on assays indicate that an impaired ability to initiate transcription largely accounts for the decreased synthesis of RNA by the senescent hepatocytes.

Myelin basic protein inhibits histone-specific protein methylase I

Bovine brain myelin basic protein, free of associated proteolytic activity, was found to be a specific inhibitor of histone-specific protein methylase I (S-adenosyl-L-methionine:protein-L-arginine N-methyltransferase, EC 2.1.1.23) purified from bovine brain. 50% of the methyl group incorporation into the histone substrate catalyzed by the methylase I was inhibited by myelin basic protein at a concentration of 0.326 mM. However, neither of the peptide fragments (residues 1-116 and residues 117-170) generated by the chemical cleavage of myelin basic protein at the tryptophan residue retained the inhibitory activity for histone-specific protein methylase I. Proteins such as gamma-globulin, bovine serum albumin, bovine pancreatic ribonuclease and polyarginine did not exhibit significant inhibitory activity toward the enzyme. The Ki value for myelin basic protein was estimated to be 3.42 X 10(-5) M for histone-specific protein methylase I and the nature of the inhibition was uncompetitive toward histone substrate.

Studies on the distribution of O6-methylguanine-DNA methyltransferase in rat

O6-Methylguanine-DNA methyltransferase, a DNA repair enzyme which transfers the methyl group of O6-methylguanine residue to a cysteinyl residue in the methyltransferase itself, was examined in rat organs by quantifying the S-methylcysteine formed in the methyl acceptor protein. Among the various organs examined, the spleen exhibited the highest enzyme specific activity followed by the thymus, liver, lung and testis. Brain had the lowest activity. The patterns of subcellular distribution of the methyltransferase in spleen and liver were different: while 75-80% of the activity was present in the nuclear fraction of the spleen, 54% of the activity in the liver was found in the nuclei and 35% in the cytosolic fraction. Forty-five and thirty-five percent of the total nuclear enzyme activity could be extracted with 1 M and 2 M NaCl solutions, respectively, indicating that the repair enzyme is not tightly bound to the nuclear matrix. When isolated nuclei were incubated with [methyl-3H]DNA substrate and subsequently fractionated into histone and non-histone protein fractions, over 90% of the radioactivity was coeluted on a Bio-Rex 70 column with the non-histone fraction and only a negligible amount of radioactivity was found to be associated with the histone fraction. The molecular mass of the [methyl-3H]methyltransferase in the non-histone fraction was determined to be 23,000, and its pI value was found to be 6.6 by two-dimensional polyacrylamide gel electrophoresis.