Isolation and regional localization of a large collection (2,000) of single-copy DNA fragments on human chromosome 3 for mapping and cloning tumor suppressor genes

Summary A collection of 2,000 lambda phage-carrying human single-copy inserts (> 700 bp) were isolated from two chromosome-3 flow-sorted libraries. The single-copy DNA fragments were first sorted into 3p and 3q locations and about 700 3p fragments were regionally mapped using a deletion mapping panel comprised of two humanhamster and two-human-mouse cell hybrids, each containing a chromosome 3 with different deletions in the short arm. The hybrids were extensively mapped with a set of standard 3p markers physically localized or ordered by linkage. The deletion mapping panel divided the short arm into five distinct subregions (A-E). The 3p fragments were distributed on 3p regions as follows: region A, 26%; B, 31%; C, 4%; D, 4% and E, 35%. We screened 300 single-copy DNA fragments from the distal part of 3p (regions A and B) with ten restriction endonucleases for their ability to detect restriction fragment length polymorphisms (RFLPs). Of these fragments 110 (36%) were found to detect useful RFLPs: 35% detected polymorphisms with frequency of heterozygosity of 40% or higher, and 25% with frequency of 30% or higher. All polymorphisms originated from single loci and most of them were of the base pair substitution type. These RFLP markers make it possible to construct a fine linkage map that will span the distal part of chromosome 3p and encompasses the von Hippel-Lindau disease locus. The large number of single-copy fragments (2,000) spaced every 100–150 kb on chromosome 3 will make a significant contribution to mapping and sequencing the entire chromosome 3. The 300 conserved chromosome 3 probes will increase the existing knowledge of man-mouse homologies.     

Adsorption equilibrium in immuno-affinity chromatography with polyclonal and monoclonal antibodies

The effects of pH, ionic strength, anion species, and antibody concentration on the adsorption equilibrium between immobilized antibodies and antigens were studied by use of anti-BSA, anti-HSA, anti-BlgG, and monoclonal anti-HSA coupled to Sepharose 4B. The polyclonal antibodies possessed average binding affinities of the order of 10(8)M(-1), and the heterogeneity was accounted for by assuming a normal distribution of the free energy of antibody-antigen combination. The monoclonal antibody, on the other hand, showed a homogeneous affinity of the Langmuir type. Bound antigens could be eluted by lowering pH or adding a chaotropic anion, and their purity was very high. The antibody ligand was sufficiently stable for repeated use.     

Differential Regulation of Intracellular Signaling Systems by Sodium Fluoride in Rat Glioma Cells

Abstract: We investigated the rapid and slow effects of NaF on intracellular signaling systems such as Ca²⁺ homeostasis and cyclic GMP (cGMP) generation in rat glioma C6 cells, using the Ca²⁺-sensitive dye fura-2 and cGMP enzyme immunoassay. We found that the following: (a) NaF enhanced cGMP generation in a concentration-dependent manner. This enhancement was abolished by pretreatment with 100 µ M BAPTA tetraacetoxymethyl ester or in the presence of W-7 in a concentration-dependent manner. N ^G-Monomethyl- l -arginine (NMMA), a competitive inhibitor of nitric oxide synthase (NOS), also inhibited the NaF-induced generation of cGMP. These results suggest that NaF-induced cGMP generation occurs via a calcium/calmodulin- and NOS-dependent pathway. (b) The basal intracellular Ca²⁺ concentration ([Ca²⁺]_i) was transiently greater at 1 and 3 h after pretreatment with NaF. W-7 and W-13 antagonized the increase in [Ca²⁺]_i, whereas NMMA had little effect. This suggests that the NaF-induced change in basal [Ca²⁺]_i was mediated by a calmodulin-dependent pathway but was independent of a NOS-sensitive pathway. (c) The serotonin (5-HT)-induced intracellular mobilization of Ca²⁺ was reduced by pretreating the cells with NaF. The reduction in Ca²⁺ mobilization was antagonized by genistein, a tyrosine kinase inhibitor. W-7, W-5, and H-8 had no effect. Results suggest that NaF differentially regulates the cGMP generation, basal [Ca²⁺]_i, and 5-HT_2A receptor function in C6 glioma cells.     

Mutational analysis of the proteolytic cleavage site of glycoprotein B (gB) of Marek''s disease virus

The Marek's disease virus (MDV) glycoprotein B (gB) precursor, gp100, is proteolytically cleaved into two disulfide-linked subunits, gp60 and gp49. In the gB homologs of most other herpesviruses, a tetrapeptide, Arg-Xaa-Arg-Arg, is immediately upstream from the predicted cleavage site. We have investigated the specificity of the proteolytic cleavage in gplOO by introducing mutations within its predicted cleavage site (Arg-Leu-Arg-Arg) and expressed these mutants in recombinant fowlpox virus (FPV). The results show that all three Arg residues at the predicted cleavage site play an important role in the specific proteolytic cleavage of gp100. Furthermore, we demonstrated that the cleavage of gplOO is not necessary for transport of gB to the cell surface.     

Measurement of endogenous leucine enkephalin in canine caudate nuclei and hypothalami with high-performance liquid chromatography and field-desorption mass spectrometry

For the first time, endogenous amounts of Leu-enkephalin are measured in brain tissue with a technique preserving integrity of the entire molecular structure of the neuropeptide. Field-desorption mass spectrometry enables measurement of picomole amounts of endogenous, chemically underivatized Leu-enkephalin in canine caudate nuclei and hypothalami. The optimal sensitivity and resolution of high-performance liquid chromatography is coupled with maximal molecular specificity of field-desorption mass spectrometry to measure enkephalins in caudate nuclei and hypothalami from dog brains. This novel combination of two recent instrumental methodologies provides a firm molecular basis for calibrating the radioimmunoassay measurement of endogenous levels of biologically active brain neuropeptides.     

Convenient synthesis of 18-hydroxylated cortisol and prednisolone.

18,20-Epoxy-11 beta,17 alpha,20 beta,21-tetrahydroxypregn-4-en-3-one was synthesized by the application of hypoiodite reaction to the cortisol acetonide. The intermediary 18-iodo derivative was converted to the 11-oxo steroid by chromic acid prior to silver ion-assisted solvolysis. Removal of the protective group with hydrochloric acid was finally carried out to give the desired 11 beta,17 alpha,18,21-tetrahydroxypregn-4-ene-3,20-dione as the hemiacetal form. 18,20-Epoxy-11 beta-17 alpha,20 beta,21- tetrahydroxypregna-1,4-dien-3-one was also prepared from prednisolone through a similar reaction sequence.     

α5β1 integrin induces the expression of noncartilaginous procollagen gene expression in articular chondrocytes cultured in monolayers

Introduction

Articular chondrocytes undergo an obvious phenotypic change when cultured in monolayers. During this change, or dedifferentiation, the expression of type I and type III procollagen is induced where normal chondrocytes express little type I and type III procollagen. In this study, we attempted to determine the mechanism(s) for the induction of such procollagen expression in dedifferentiating chondrocytes.

Methods

All experiments were performed using primary-cultured human articular chondrocytes under approval of institutional review boards. Integrin(s) responsible for the induction of type I and type III procollagen expression were specified by RNAi experiments. The signal pathway(s) involved in the induction were determined by specific inhibitors and RNAi experiments. Adenovirus-mediated experiments were performed to identify a small GTPase regulating the activity of integrins in dedifferentiating chondrocytes. The effect of inhibition of integrins on dedifferentiation was investigated by experiments using echistatin, a potent disintegrin. The effect of echistatin was investigated first with monolayer-cultured chondrocytes, and then with pellet-cultured chondrocytes.

Results

In dedifferentiating chondrocytes, α5β1 integrin was found to be involved in the induction of type I and type III procollagen expression. The induction was known to be mediated by v-akt murine thymoma viral oncogene homolog (AKT) signaling. Among the three AKT isoforms, AKT1 seemed to be most involved in the signaling. Elated RAS viral (r-ras) oncogene homolog (RRAS) was considered to regulate the progression of dedifferentiation by modulating the affinity and avidity of α5β1 integrin to ligands. Echistatin inhibited dedifferentiation of monolayer-cultured chondrocytes. Furthermore, the matrix formed by pellet-cultured chondrocytes more closely resembled that of normal cartilage compared with the controls.

Conclusions

The result of this study has shown, for the first time, that α5β1 integrin may be responsible for the induction of non-cartilaginous collagen expression in chondrocytes undergoing dedifferentiation. Again, this study has shown that the inhibition of ligand ligation to integrins may be an effective strategy to inhibit phenotypic change of cultured chondrocytes, and to improve the quality of matrix synthesized by primary cultured chondrocytes.     

Rates of Serious Intracellular Infections in Autoimmune Disease Patients Receiving Initial Glucocorticoid Therapy

Background/Aims

The Japanese National Hospital Organization evidence-based medicine (EBM) Study group for Adverse effects of Corticosteroid therapy (J-NHOSAC) is a Japanese hospital-based cohort study investigating the safety of the initial use of glucocorticoids (GCs) in patients with newly diagnosed autoimmune diseases. Using the J-NHOSAC registry, the purpose of this observational study is to analyse the rates, characteristics and associated risk factors of intracellular infections in patients with newly diagnosed autoimmune diseases who were initially treated with GCs.

Methodology/Principal Findings

A total 604 patients with newly diagnosed autoimmune diseases treated with GCs were enrolled in this registry between April 2007 and March 2009. Cox proportional-hazards regression was used to determine independent risk factors for serious intracellular infections with covariates including sex, age, co-morbidity, laboratory data, use of immunosuppressants and dose of GCs. Survival was analysed according to the Kaplan-Meier method and was assessed by the log-rank test. There were 127 serious infections, including 43 intracellular infections, during 1105.8 patient-years of follow-up. The 43 serious intracellular infections resulted in 8 deaths. After adjustment for covariates, diabetes (Odds ratio [OR]: 2.5, 95% confidence interval [95% CI] 1.1–5.9), lymphocytopenia (≦1000/μl, OR: 2.5, 95% CI 1.2–5.2) and use of high-dose (≧30 mg/day) GCs (OR: 2.4, 95% CI 1.1–5.3) increased the risk of intracellular infections. Survival curves showed lower intracellular infection-free survival rate in patients with diabetes, lymphocytopaenia and high-dose GCs treatments.

Conclusions/Significance

Patients with newly diagnosed autoimmune diseases were at high risk of developing intracellular infection during initial treatment with GCs. Our findings provide background data on the risk of intracellular infections of patients with autoimmune diseases. Clinicians showed remain vigilant for intracellular infections in patients with autoimmune diseases who are treated with GCs.     

Epistatic Interaction between BANK1 and BLK in Rheumatoid Arthritis: Results from a Large Trans-Ethnic Meta-Analysis

Background

BANK1 and BLK belong to the pleiotropic autoimmune genes; recently, epistasis between BANK1 and BLK was detected in systemic lupus erythematosus. Although BLK has been reproducibly identified as a risk factor in rheumatoid arthritis (RA), reports are conflicting about the contribution of BANK1 to RA susceptibility. To ascertain the real impact of BANK1 on RA genetic susceptibility, we performed a large meta-analysis including our original data and tested for an epistatic interaction between BANK1 and BLK in RA susceptibility.

Patients and Methods

We investigated data for 1,915 RA patients and 1,915 ethnically matched healthy controls genotyped for BANK1 rs10516487 and rs3733197 and BLK rs13277113. The association of each SNP and RA was tested by logistic regression. Multivariate analysis was then used with an interaction term to test for an epistatic interaction between the SNPs in the 2 genes.

Results

None of the SNPs tested individually was significantly associated with RA in the genotyped samples. However, we detected an epistatic interaction between BANK1 rs3733197 and BLK rs13277113 (P_interaction = 0.037). In individuals carrying the BLK rs13277113 GG genotype, presence of the BANK1 rs3733197 G allele increased the risk of RA (odds ratio 1.21 [95% confidence interval 1.04–1.41], P = 0.015. Combining our results with those of all other studies in a large trans-ethnic meta-analysis revealed an association of the BANK1 rs3733197 G allele and RA (1.11 [1.02–1.21], P = 0.012).

Conclusion

This study confirms BANK1 as an RA susceptibility gene and for the first time provides evidence for epistasis between BANK1 and BLK in RA. Our results illustrate the concept of pleiotropic epistatic interaction, suggesting that BANK1 and BLK might play a role in RA pathogenesis.     

Human Leukocyte Antigen and Systemic Sclerosis in Japanese: The Sign of the Four Independent Protective Alleles,DRB1*13:02, DRB1*14:06, DQB1*03:01, and DPB1*02:01

ObjectiveSeveral studies on associations between human leukocyte antigen (HLA) allele frequencies and susceptibility to systemic sclerosis (SSc) have been reported. Anti-centromere antibodies (ACA) and anti-topoisomerase I antibodies (ATA) are found in SSc patients. Here, we sought to identify HLA alleles associated with SSc in Japanese, and explored their associations with SSc phenotypes including the presence of autoantibodies.MethodsAssociations of HLA-DRB1, DQB1, and DPB1 were analyzed in 463 Japanese SSc patients and 413 controls.ResultsWe found that DRB1*13:02 (P = 0.0011, Pc = 0.0319, odds ratio [OR] 0.46, 95% confidence interval [CI] 0.29–0.73), DRB1*14:06 (P = 6.60X10^-5, Pc = 0.0020, OR 0.05, 95%CI 0.01–0.41), DQB1*03:01 (P = 0.0009, Pc = 0.0150, OR 0.56, 95%CI 0.40–0.79), and DPB1*02:01 (P = 5.16X10^-6, Pc = 8.77X10^-5, OR 0.52, 95%CI 0.39–0.69) were protectively associated with SSc. In addition, these four alleles seemed to be independently associated with the protection against the susceptibility of SSc. On the other hand, we could not find predisposing alleles for overall SSc. With respect to SSc subsets, a tendency for these four alleles to be protectively associated was observed. However, there was a significant association between DRB1*01:01, DRB1*10:01, DQB1*05:01, and DPB1*04:02 and the susceptibility to SSc with ACA. On the other hand, the presence of DRB1*15:02, DQB1*06:01, DPB1*03:01, and DPB1*09:01 was associated with SSc with ATA.ConclusionThus, the present study has identified protective associations of the four HLA class II alleles with overall Japanese SSc and predisposing associations of HLA class II alleles with Japanese SSc subsets.