Comparison of methods for profiling O-glycosylation: Human Proteome Organisation Human Disease Glycomics/Proteome Initiative multi-institutional study of IgA1.

The Human Proteome Organisation Human Disease Glycomics/Proteome Initiative recently coordinated a multi-institutional study that evaluated methodologies that are widely used for defining the N-glycan content in glycoproteins. The study convincingly endorsed mass spectrometry as the technique of choice for glycomic profiling in the discovery phase of diagnostic research. The present study reports the extension of the Human Disease Glycomics/Proteome Initiative's activities to an assessment of the methodologies currently used for O-glycan analysis. Three samples of IgA1 isolated from the serum of patients with multiple myeloma were distributed to 15 laboratories worldwide for O-glycomics analysis. A variety of mass spectrometric and chromatographic procedures representative of current methodologies were used. Similar to the previous N-glycan study, the results convincingly confirmed the pre-eminent performance of MS for O-glycan profiling. Two general strategies were found to give the most reliable data, namely direct MS analysis of mixtures of permethylated reduced glycans in the positive ion mode and analysis of native reduced glycans in the negative ion mode using LC-MS approaches. In addition, mass spectrometric methodologies to analyze O-glycopeptides were also successful.

The Caenorhabditis elegans bus-2 mutant reveals a new class of O-glycans affecting bacterial resistance.

Microbacterium nematophilum causes a deleterious infection of the C. elegans hindgut initiated by adhesion to rectal and anal cuticle. C. elegans bus-2 mutants, which are resistant to M. nematophilum and also to the formation of surface biofilms by Yersinia sp., carry genetic lesions in a putative glycosyltransferase containing conserved domains of core-1 beta1,3-galactosyltransferases. bus-2 is predicted to act in the synthesis of core-1 type O-glycans. This observation implies that the infection requires the presence of host core-1 O-glycoconjugates and is therefore carbohydrate-dependent. Chemical analysis reported here reveals that bus-2 is indeed deficient in core-1 O-glycans. These mutants also exhibit a new subclass of O-glycans whose structures were determined by high performance tandem mass spectrometry; these are highly fucosylated and have a novel core that contains internally linked GlcA. Lectin studies showed that core-1 glycans and this novel class of O-glycans are both expressed in the tissue that is infected in the wild type worms. In worms having the bus-2 genetic background, core-1 glycans are decreased, whereas the novel fucosyl O-glycans are increased in abundance in this region. Expression analysis using a red fluorescent protein marker showed that bus-2 is expressed in the posterior gut, cuticle seam cells, and spermatheca, the first two of which are likely to be involved in secreting the carbohydrate-rich surface coat of the cuticle. Therefore, in the bus-2 background of reduced core-1 O-glycans, the novel fucosyl glycans likely replace or mask remaining core-1 ligands, leading to the resistance phenotype. There are more than 35 Microbacterium species, some of which are pathogenic in man. This study is the first to analyze the biochemistry of adhesion to a host tissue by a Microbacterium species.

Cardiovascular disease delay in centenarian offspring: role of heat shock proteins.

Cardiovascular disease is a major cause of morbidity and mortality of older Americans. We have demonstrated recently that centenarian offspring, when compared with age-matched controls, avoid and/or delay cardiovascular disease and cardiovascular risk factors. Given recent evidence suggesting that higher circulating levels of HSP70 predict the future development of cardiovascular disease in established hypertensives and a recent study demonstrating a decrease in HSP60 and HSP70 with advancing age, we hypothesized that HSP70 levels would be lower in centenarian offspring compared with controls. The circulating serum concentration of HSP70 in 20 centenarian offspring and 9 spousal controls was analyzed using a modified HSP70 ELISA method. Centenarian offspring showed approximately 10-fold lower levels of circulating serum HSP70 compared with spousal controls (P <.001). The exact biological significance of the extremely low levels of circulating serum HSP70 observed in centenarian offspring thus far is not clear. However, circulating HSP has been shown to correlate in diseases or disorders in which there is destruction or damage to target tissues or organs, including cardiovascular diseases and numerous autoimmune disorders. We hypothesize that low levels of circulating serum HSP70 may be an indicator of a healthy state and point to longevity of the host; therefore, our results suggest that levels of circulating serum HSP70 may be a marker for longevity.

Sickle cell vaso-occlusive crisis induces the release of circulating serum heat shock protein-70.

Inflammation may play an important role in the pathophysiology of sickle cell disease (SCD), and recent studies have identified the 70-kDa heat shock protein (Hsp70) as an important mediator of inflammatory responses. Here we demonstrate a significant increase in circulating serum Hsp70 level in SCD during vaso-occlusive crisis (VOC) as compared with baseline steady-state levels (P <0.05) and a significant increase in Hsp70 levels in SCD at baseline compared with normal controls (P <0.05). Taken together, these results indicate that circulating serum Hsp70 might be a marker for VOC in SCD.