Common sequence variants of the macrophage scavenger receptor 1 gene are associated with prostate cancer risk

Rare germline mutations of macrophage scavenger receptor 1 (MSR1) gene were reported to be associated with prostate cancer risk in families with hereditary prostate cancer (HPC) and in patients with non-HPC (Xu et al. 2002). To further evaluate the role of MSR1 in prostate cancer susceptibility, at Johns Hopkins Hospital, we studied five common variants of MSR1 in 301 patients with non-HPC who underwent prostate cancer treatment and in 250 control subjects who participated in prostate cancer-screening programs and had normal digital rectal examination and PSA levels (<4 ng/ml). Significantly different allele frequencies between case subjects and control subjects were observed for each of the five variants (P value range.01-.04). Haplotype analyses provided consistent findings, with a significant difference in the haplotype frequencies from a global score test (P=.01). Because the haplotype that is associated with the increased risk for prostate cancer did not harbor any of the known rare mutations, it appears that the observed association of common variants and prostate cancer risk are independent of the effect of the known rare mutations. These results consistently suggest that MSR1 may play an important role in prostate carcinogenesis.     

Mutation analysis in Rett syndrome

Rett syndrome is an X-linked dominant neurodevelopmental disorder caused by mutations in the MECP2 gene. Mutations have been demonstrated in more than 80% of females with typical features of Rett syndrome. We identified mutations in the MECP2 gene and documented the clinical manifestations in 65 Rett syndrome patients to characterize the genotype-phenotype spectrum. Bidirectional sequencing of the entire MECP2 coding region was performed. We diagnosed 65 patients with MECP2 mutations. Of these, 15 mutations had been reported previously and 13 are novel. Two patients have multiple deletions within the MECP2 gene. Eight common mutations were found in 43 of 65 patients (66.15%). The majority of patients with identified mutations have the classic Rett phenotype, and several had atypical phenotypes. MECP2 analysis identified mutations in almost all cases of typical Rett syndrome, as well as in some with atypical phenotypes. Eleven (20.4%) of the 54 patients with defined mutations and in whom phenotypic data were obtained did not develop acquired microcephaly. Hence, microcephaly at birth or absence of acquired microcephaly does not obviate the need for MECP2 analysis. We have initiated cascade testing starting with PCR analysis for common mutations followed by sequencing, when necessary. Analysis of common mutations before sequencing the entire gene is anticipated to be the most efficacious strategy to identify Rett syndrome gene mutations.     

Autosomal dominant stapes ankylosis with broad thumbs and toes,hyperopia, and skeletal anomalies is caused by heterozygous nonsense and frameshift mutations in NOG,the gene encoding noggin

Although fixation of the stapes is usually progressive and secondary to otosclerosis, it may present congenitally, with other skeletal manifestations, as an autosomal dominant syndrome-such as proximal symphalangism (SYM1) or multiple-synostoses syndrome (SYNS1), both of which are caused by mutations in NOG, the gene encoding noggin. We describe a family that was ascertained to have nonsyndromic otosclerosis but was subsequently found to have a congenital stapes ankylosis syndrome that included hyperopia, a hemicylindrical nose, broad thumbs and great toes, and other minor skeletal anomalies but lacked symphalangism. A heterozygous nonsense NOG mutation-c.328C-->T (Q110X), predicted to truncate the latter half of the protein-was identified, and a heterozygous insertion in NOG-c.252-253insC, in which the frameshift is predicted to result in 96 novel amino acids before premature truncation-was identified in a previously described second family with a similar phenotype. In contrast to most NOG mutations that have been reported in kindreds with SYM1 and SYNS1, the mutations observed in these families with stapes ankylosis without symphalangism are predicted to disrupt the cysteine-rich C-terminal domain. These clinical and molecular findings suggest that (1) a broader range of conductive hearing-loss phenotypes are associated with NOG mutations than had previously been recognized, (2) patients with sporadic or familial nonsyndromic otosclerosis should be evaluated for mild features of this syndrome, and (3) NOG alterations should be considered in conductive hearing loss with subtle clinical and skeletal features, even in the absence of symphalangism.     

Connexin-30 deletion analysis in connexin-26 heterozygotes

Mutations in the Connexin-26 gene (Cx 26, GJB2) are the most common cause of hereditary nonsyndromic sensorineural hearing loss (SNHL). DNA analysis of the Cx 26 gene in deaf or hard-of-hearing individuals frequently demonstrates heterozygosity despite the fact that most mutations are known to be recessive. A 342-kb deletion in a gene adjacent to Cx 26, the Connexin-30 gene (Cx 30, GJB6), has been reported to cause deafness in the homozygous state or in combination with heterozygous mutations in Cx 26 (digenic inheritance). We have analyzed deaf or hard-of-hearing Cx 26 heterozygotes and individuals with no mutations in Cx 26 for this Cx 30 deletion. We found that 4/20 (20%) of the Cx 26 heterozygotes are heterozygous for this deletion and that no individuals were homozygous for the Cx 30 deletion. Cx 30 deletion analysis is recommended for all individuals with nonsyndromic SNHL following Cx 26 sequencing that does not demonstrate two recessive mutations.     

Polymerization on the Rocks: Negatively-Charged α-amino acids

Oligomers of the negatively-charged amino acids, glutamic acid, aspartic acid, and O-phospho-L-serine are adsorbed by hydroxylapatite and illite with affinities that increase with oligomer length. In the case of oligo-glutamic acids adsorbed on hydroxylapatite, addition of an extra residue results in an approximately four-fold increase in the strength of adsorption. Oligomers much longer than the 7-mer are retained tenaciously by the mineral. Repeated incubation of short oligo-glutamic acids adsorbed on hydroxylapatite or illite with activated monomer leads to the accumulation of oligomers at least 45 units long. The corresponding reactions of aspartic acid and O-phospho-L-serine on hydroxylapatite are less effective in generating long oligomers, while illite fails to accumulate substantial amounts of long oligomers of aspartic acid or of O-phospho-L-serine.     

Antibody microarray analysis of inflammatory mediator release by human leukemia T-cells and human non small cell lung cancer cells.

Cytokines and chemokines are responsible for regulating inflammation and the immune response. Cytokine and chemokine release is typically measured by quantitative enzyme-linked immunosorbant assay (ELISA) or Western blot analysis. To expedite the analysis of samples for multiple cytokines/chemokines, we have developed slide-based Thermo Scientific ExcelArray Antibody Sandwich Microarrays. Each slide consists of 16 subarrays (wells), each printed with 12 specific antibodies in triplicate and positive and negative control elements. This 16-well format allows for the analysis of 10 test samples using a six-point standard curve. The array architecture is based on the "sandwich" ELISA, in which an analyte protein is sandwiched between an immobilized capture antibody and a biotinylated detection antibody, using streptavidin-linked Thermo Scientific DyLight 649 Dye for quantitation. The observed sensitivity of this assay was <10 pg/mL. In our experiments, the Jurkat cell line was used as a model for human T-cell leukemia, and the A549 cell line was used as a model for human non-small cell lung cancer. To evoke a cytokine/chemokine response, cells were stimulated with tumor necrosis factor alpha (TNFalpha), phorbol-12-myristate-13-acetate (PMA, TPA), and phytohemagglutinin (PHA). Cell supernatants derived from both untreated and stimulated cells were analyzed on four different arrays (Inflammation I, Inflammation II, Angiogenesis, and Chemotaxis), enabling the quantitation of 41 unique analytes. Stimulated cells showed an increase in the expression level of many of the test analytes, including IL-8, TNF-alpha, and MIP-1alpha, compared to the non-treated controls. Our experiments clearly demonstrate the utility of antibody microarray analysis of cell-culture supernatants for the profiling of cellular inflammatory mediator release.     

An evolutionarily conserved Rit GTPase-p38 MAPK signaling pathway mediates oxidative stress resistance

Ras-related small GTP-binding proteins control a wide range of cellular processes by regulating a variety of effector pathways, including prominent roles in the control of mitogen-activated protein kinase (MAPK) cascades. Although the regulatory role(s) for many Ras family GTPases are well established, the physiological function for the Rit/Rin subfamily has been lacking. Here, using both knockout mice and Drosophila models, we demonstrate an evolutionarily conserved role for Rit subfamily GTPases (mammalian Rit and Rin, and the Drosophila RIC homologue) in governing survival in response to oxidative stress. Primary embryonic fibroblasts derived from Rit knockout mice display increased apoptosis and selective disruption of MAPK signaling following reactive oxygen species (ROS) exposure but not in response to endoplasmic reticulum stress or DNA damage. These deficits include a reduction in ROS-mediated stimulation of a p38-MK2-HSP27 signaling cascade that controls Akt activation, directing Bad phosphorylation to promote cell survival. Furthermore, D-RIC null flies display increased susceptibility to environmental stresses and reduced stress-dependent p38 signaling, extending the Rit-p38 survival pathway to Drosophila. Together, our studies establish the Rit GTPases as critical regulators of an evolutionarily conserved, p38 MAPK-dependent signaling cascade that functions as an important survival mechanism for cells in response to oxidative stress.