THE IMMUNOGLOBULINS OF MICE : V. THE METABOLIC (CATABOLIC) PROPERTIES OF FIVE IMMUNOGLOBULIN CLASSES

The metabolic properties of immunoglobulin were investigated by comparing five classes of mouse immunoglobulin. Three forms of 7S immunoglobulin had different rates of catabolism. The fractional rates of catabolism were found to be about 13 per cent per day for 7S γ2a-globulin; 25 per cent for 7S γ2b-globulin; and 17 per cent for 7S γ1-globulin. Catabolism of the three classes of 7S γ-globulin (γ2a, γ2b, and γ1) were prolonged at low serum 7S γ-globulin levels and accelerated at high serum 7S γ-globulin levels. Each of the 7S γ-globulin components was influenced by the serum level of the other mouse 7S γ-globulin components and by exogenously administered human 7S γ-globulin. They were not appreciably altered, however, by the serum level of IgA (γ1A-, β2A-globulin). The progressively changing (longer) half-times observed in turnover studies of normal IgG (7S γ-globulin) may be caused by catabolic heterogeneity of normal 7S immunoglobulins which are immunochemically and catabolically related to γ2a-, γ2b-, and 7S γ1-myeloma proteins. These studies indicate that the 7S γ2a-, 7S γ2b-, and 7S γ1-globulins share a common catabolic control mechanism. This mechanism is influenced by the serum level of each of these components, but is independent of the serum level of IgA (γ1A-globulin) and probably is independent of IgM (γ1M-globulin). Catabolism of IgA (γ1A-, β2A-globulin) and IgM (γ1M-globulin) was much more rapid than the catabolism of the 7S γ-globulins. The halftimes of the IgA and IgM were approximately 1.2 and 0.5 days respectively. The fractional rate of catabolism of IgA and IgM seemed to be independent of their serum concentration. The rate of catabolism, as well as the rate of synthesis, was shown to play a major role in determining the serum level of each class of immunoglobulin

Networks of intergenic long-range enhancers and snpRNAs drive castration-resistant phenotype of prostate cancer and contribute to pathogenesis of multiple common human disorders

Biological and mechanistic relevance of intergenic disease-associated genetic loci (IDAGL) containing highly statistically significant disease-linked SNPs remains unknown. Here we present the experimental and clinical evidence revealing important role of IDAGL in human diseases. Targeted RT-PCR screen coupled with sequencing of purified PCR products detects widespread transcription at multiple intergenic disease-associated genomic loci (IDAGL) and identifies 96 small non-coding trans-regulatory RNAs of ~ 100-300 nt in length containing SNPs associated with 21 common human disorders (snpRNAs). Functionality of snpRNAs is supported by multiple independent lines of experimental evidence demonstrating their cell-type-specific expression and evolutionary conservation of sequences, genomic coordinates, and biological effects. Analysis of chromatin state signatures, expression profiling experiments using microarray and Q-PCR technologies, and luciferase reporter assays indicate that many IDAGL are Polycomb-regulated long-range enhancers. Expression of snpRNAs in human and mouse cells markedly affects cellular behavior and induces allele-specific clinically-relevant phenotypic changes: NLRP1-locus snpRNAs exert regulatory effects on monocyte/macrophage trans-differentiation, induce prostate cancer (PC) susceptibility snpRNAs, and transform low-malignancy hormone-dependent human PC cells into highly malignant androgen-independent PC. Q-PCR analysis and luciferase reporter assays demonstrate that snpRNA sequences represent allele-specific “decoy” targets of microRNAs which function as SNP-allele-specific modifiers of microRNA expression and activity. We demonstrate that trans-acting RNA molecules facilitating androgen depletion-independent growth (ADIG) in vitro and castration-resistant (CR) phenotype in vivo of PC contain intergenic 8q24-locus SNP variants which were recently linked with increased risk of developing PC. Expression level of 8q24-locus PC susceptibility snpRNAs is regulated by NLRP1-locus snpRNAs, which are transcribed from the intergenic long-range enhancer sequence located in 17p13 region at ~ 30 kb distance from the NLRP1 gene. Q-PCR analysis of clinical PC samples reveals markedly increased snpRNA expression levels in tumor tissues compared to the adjacent normal prostate [122-fold and 45-fold in Gleason 7 tumors (p = 0.03); 370-fold and 127-fold in Gleason 8 tumors (p = 0.0001); for NLRP1-locus and 8q24-locus SnpRNAs, respectively]. Highly concordant expression profiles of the NLRP1-locus snpRNAs and 8q24 CR-locus snpRNAs (r = 0.896; p < 0.0001) in clinical PC samples and experimental evidence of trans-regulatory effects of NLRP1-locus snpRNAs on expression of 8q24-locus SnpRNAs indicate that ADIG and CR phenotype of human PC cells can be triggered by RNA molecules transcribed from the NLRP1-locus intergenic enhancer and down-stream activation of the 8q24-locus snpRNAs. Our results define the intergenic NLRP1 and 8q24 regions as regulatory loci of ADIG and CR phenotype of human PC, reveal previously unknown molecular links between the innate immunity/inflammasome system and development of hormone-independent PC, and identify novel diagnostic and therapeutic targets exploration of which should be highly beneficial for clinical management of PC