Lipid mediator metabolic profiling demonstrates differences in eicosanoid patterns in two phenotypically distinct mast cell populations

Mast cells are inflammatory cells that play key roles in health and disease. They are distributed in all tissues and appear in two main phenotypes, connective tissue and mucosal mast cells, with differing capacities to release inflammatory mediators. A metabolic profiling approach was used to obtain a more comprehensive understanding of the ability of mast cell phenotypes to produce eicosanoids and other lipid mediators. A total of 90 lipid mediators (oxylipins) were characterized using liquid chromatography-tandem mass spectrometry (LC-MS/MS), representing the cyclooxygenase (COX), lipoxygenase (LO), and cytochrome P450 (CYP) metabolic pathways. In vitro-derived murine mucosal-like mast cells (MLMC) and connective tissue-like mast cells (CTLMC) exhibited distinct mRNA expression patterns of enzymes involved in oxylipin biosynthesis. Oxylipins produced by 5-LO and COX pathways were the predominant species in both phenotypes, with 5-LO products constituting 90 ± 2% of the CTLMCs compared with 58 ± 8% in the MLMCs. Multivariate analyses demonstrated that CTLMCs and MLMCs secrete differing oxylipin profiles at baseline and following calcium ionophore stimulation, evidencing specificity in both a time- and biosynthetic pathway-dependent manner. In addition to the COX-regulated prostaglandin PGD₂ and 5-LO-regulated cysteinyl-leukotrienes (e.g., LTC₄), several other mediators evidenced phenotype-specificity, which may have biological implications in mast cell-mediated regulation of inflammatory responses.     

Detecting multivariate differentially expressed genes

Background  

Gene expression is governed by complex networks, and differences in expression patterns between distinct biological conditions may therefore be complex and multivariate in nature. Yet, current statistical methods for detecting differential expression merely consider the univariate difference in expression level of each gene in isolation, thus potentially neglecting many genes of biological importance.     

ProAlanase is an Effective Alternative to Trypsin for Proteomics Applications and Disulfide Bond Mapping

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Highlights

• •ProAlanase is a powerful protease for efficient low pH disulfide bond mapping.
• •High suitability for analysis of histone family members and their PTMs.
• •Accurate phosphorylation profiling in proline-rich proteins.
• •Sequence coverage increase and full de novo sequencing in combination with trypsin.

     

Mapping bone microstructure trace element composition: Sr,Ba, Cu,and Pb in an early modern Danish skeleton

Objectives

A Geographical Information System (GIS) approach enhances the acquisition, management, and analysis of trace element data from cortical bone. A high-resolution spatial dimension expands the research potential of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) data from cortical bone cross-sections. The chemical characterization of hundreds of osteons, notably sequences of superimposed osteons, permits more exacting studies of individual life histories than is possible with analyses of bulk bone samples.

Methods

A GIS procedure was used to estimate Sr, Ba, Pb, and Cu concentrations, originally generated through LA-ICP-MS, for bone microstructural features, notably fragmentary and intact osteons, in a human femoral cross-section. The skeleton is from Ribe, Denmark, and dates to the early modern period.

Results

Postmortem chemical alteration was limited to the bone's outer and inner margins. Two dietary indicators, Sr and Ba, and two socioeconomic indicators, Pb and Cu, measured for individual osteons were correlated with one another. Osteon sequences indicate concentrations of all four elements increased late in life for this individual.

Conclusions

The application of GIS procedures expedites fine-grained analyses of variation in the distribution of trace elements in bone microstructure identifiable in cortical bone cross-sections. It provides an efficient means of extracting the most information possible from LA-ICP-MS data about the lives of people in the past. Combining the two procedures makes it easier to track exposure to elements such as Pb across the part of an individual's life represented by osteon sequences.

     

Geoducks (Panopea abrupta) as isotopic bioarchives of seasonality in the climate of British Columbia

Geochemical analyses of geoduck shells (Panopea abrupta) have yielded new high-resolution isotope records of individual growth increments. The geoducks, which were collected from Parry Passage at Langara Island, British Columbia, are the most northern specimens that have yet been analyzed for stable oxygen and carbon isotopes. The isotope records represent the entire shell growth during the calendar years 1918, 1987, and 1991. The analyses showed that values of δ¹⁸O_shell and δ¹³C_shell vary within their growth increments. Temperature derived from δ¹⁸O_shell is consistent with modern instrumental data of sea-surface temperature. High-resolution δ¹⁸O records from individual growth increments substantiate the assumption that they are formed annually. The instrumental data indicate that the growth season was from May through October/November. The sea temperature became gradually warmer during the beginning of the growth season, and decreased steeply during autumn. Similar subannual trends can be recognized in shells growing almost a century ago. Correlation between δ¹⁸O_shell and δ¹³C_shell is negative for 1917–1919 and 1986–1988, whereas the correlation is positive for 1990–1992. Differences in correlation may be related to the composition of available food particles, i.e., algal blooms and plant debris. The food composition is partially affected by the Pacific Decadal Oscillation (PDO). These findings have major implications for the understanding of the interpretation of carbon isotopes in marine bivalves. Because of their spatial and temporal distribution, the geoduck shells are highly suitable for oceanographic reconstructions using stable-isotope analysis and sclerochronology. Furthermore, the large shell size and thickness and their deeply buried life position suggest a high preservation potential in ancient deposits. It is well known that the genus Panopea has a long-range fossil record.     

Comparative Analysis of Protocols to Induce Human CD4+Foxp3+ Regulatory T Cells by Combinations of IL-2, TGF-beta,Retinoic Acid,Rapamycin and Butyrate

Regulatory T cells (Tregs) suppress other immune cells and are critical mediators of peripheral tolerance. Therapeutic manipulation of Tregs is subject to numerous clinical investigations including trials for adoptive Treg transfer. Since the number of naturally occurring Tregs (nTregs) is minute, it is highly desirable to develop a complementary approach of inducing Tregs (iTregs) from naïve T cells. Mouse studies exemplify the importance of peripherally induced Tregs as well as the applicability of iTreg transfer in different disease models. Yet, procedures to generate iTregs are currently controversial, particularly for human cells. Here we therefore comprehensively compare different established and define novel protocols of human iTreg generation using TGF-β in combination with other compounds. We found that human iTregs expressed several Treg signature molecules, such as Foxp3, CTLA-4 and EOS, while exhibiting low expression of the cytokines Interferon-γ, IL-10 and IL-17. Importantly, we identified a novel combination of TGF-β, retinoic acid and rapamycin as a robust protocol to induce human iTregs with superior suppressive activity in vitro compared to currently established induction protocols. However, iTregs generated by these protocols did not stably retain Foxp3 expression and did not suppress in vivo in a humanized graft-versus-host-disease mouse model, highlighting the need for further research to attain stable, suppressive iTregs. These results advance our understanding of the conditions enabling human iTreg generation and may have important implications for the development of adoptive transfer strategies targeting autoimmune and inflammatory diseases.     

Voluntary Exercise Prevents Cisplatin-Induced Muscle Wasting during Chemotherapy in Mice

Loss of muscle mass related to anti-cancer therapy is a major concern in cancer patients, being associated with important clinical endpoints including survival, treatment toxicity and patient-related outcomes. We investigated effects of voluntary exercise during cisplatin treatment on body weight, food intake as well as muscle mass, strength and signalling. Mice were treated weekly with 4 mg/kg cisplatin or saline for 6 weeks, and randomized to voluntary wheel running or not. Cisplatin treatment induced loss of body weight (29.8%, P<0.001), lean body mass (20.6%, P = 0.001), as well as anorexia, impaired muscle strength (22.5% decrease, P<0.001) and decreased glucose tolerance. In addition, cisplatin impaired Akt-signalling, induced genes related to protein degradation and inflammation, and reduced muscle glycogen content. Voluntary wheel running during treatment attenuated body weight loss by 50% (P<0.001), maintained lean body mass (P<0.001) and muscle strength (P<0.001), reversed anorexia and impairments in Akt and protein degradation signalling. Cisplatin-induced muscular inflammation was not prevented by voluntary wheel running, nor was glucose tolerance improved. Exercise training may preserve muscle mass in cancer patients receiving cisplatin treatment, potentially improving physical capacity, quality of life and overall survival.