The receptor for advanced glycation endproducts (RAGE) modulates T cell signaling.

The receptor for advanced glycation endproducts (RAGE) is expressed in T cells after activation with antigen and is constitutively expressed in T cells from patients at-risk for and with type 1 diabetes mellitus (T1D). RAGE expression was associated with an activated T cell phenotype, leading us to examine whether RAGE is involved in T cell signaling. In primary CD4+ and CD8+ T cells from patients with T1D or healthy control subjects, RAGE- cells showed reduced phosphorylation of Erk. To study T cell receptor signaling in RAGE+ or-T cells, we compared signaling in RAGE+/+ Jurkat cells, Jurkat cells with RAGE eliminated by CRISPR/Cas9, or silenced with siRNA. In RAGE KO Jurkat cells, there was reduced phosphorylation of Zap70, Erk and MEK, but not Lck or CD3ξ. RAGE KO cells produced less IL-2 when activated with anti-CD3 +/- anti-CD28. Stimulation with PMA restored signaling and (with ionomycin) IL-2 production. Silencing RAGE with siRNA also decreased signaling. Our studies show that RAGE expression in human T cells is associated with an activated signaling cascade. These findings suggest a link between inflammatory products that are found in patients with diabetes, other autoimmune diseases, and inflammation that may enhance T cell reactivity.

ß cell responses to inflammation.

BACKGROUND: The extended and clinically silent progression of Type 1 diabetes (T1D) creates a challenge for clinical interventions and for understanding the mechanisms that underlie its pathogenesis. Over the course of the development of Type 1 diabetes, studies in animal models and of human tissues have identified adaptive changes in ß cells that may affect their immunogenicity and susceptibility to killing. Loss of ß cells has traditionally been identified by impairment in function but environmental factors may affect these measurements. SCOPE OF REVIEW: In this review we will highlight features of ß cell responses to cell death, particularly in the setting of inflammation, and focus on methods of detecting ß cell death in vivo. MAJOR CONCLUSIONS: We developed an assay to measure ß cell death in vivo by detecting cell free DNA with epigenetic modifications of the INS gene that are found in ß cells. This assay has robust technical performance and identifies killing in individuals at very high risk for disease, but its ability to identify ß cell killing in at-risk relatives is limited by the short half-life of the cell free DNA and the need for repeated sampling over an extended course. We present results from the Diabetes Prevention Trial-1 using this assay. In addition, recent studies have identified cellular adaptations in some ß cells that may avoid killing but impair metabolic function. Cells with these characteristics may aggravate the autoimmune response but also may represent a potentially recoverable source of functional ß cells.

Ethanol production from residual wood chips of cellulose industry: acid pretreatment investigation, hemicellulosic hydrolysate fermentation, and remaining solid fraction fermentation by SSF process.

Current research indicates the ethanol fuel production from lignocellulosic materials, such as residual wood chips from the cellulose industry, as new emerging technology. This work aimed at evaluating the ethanol production from hemicellulose of eucalyptus chips by diluted acid pretreatment and the subsequent fermentation of the generated hydrolysate by a flocculating strain of Pichia stipitis. The remaining solid fraction generated after pretreatment was subjected to enzymatic hydrolysis, which was carried out simultaneously with glucose fermentation [saccharification and fermentation (SSF) process] using a strain of Saccharomyces cerevisiae. The acid pretreatment was evaluated using a central composite design for sulfuric acid concentration (1.0-4.0 v/v) and solid to liquid ratio (1:2-1:4, grams to milliliter) as independent variables. A maximum xylose concentration of 50 g/L was obtained in the hemicellulosic hydrolysate. The fermentation of hemicellulosic hydrolysate and the SSF process were performed in bioreactors and the final ethanol concentrations of 15.3 g/L and 28.7 g/L were obtained, respectively.

Sugar cane bagasse as feedstock for second generation ethanol production: part II: hemicellulose hydrolysate fermentability

Sugar cane bagasse is produced in Brazil as waste of the sugar and ethanol industries. This lignocellulosic material is a potential source for second-generation ethanol production; however a pretreatment stage is essential, which aims at removing the hemicellulose component by disorganizing the lignocellulosic complex. In this work sugar cane bagasse was pretreated by diluted acid hydrolysis resulting in xylose-rich hydrolysates, which could be fermented to ethanol by a strain of the yeast Pichia stipitis. Statistical approach was used to investigate the effects of factors associated with the diluted acid hydrolysis process (acid concentration, solid:liquid ratio and time of exposure) on the fermentability of different hydrolysates. The statistical analysis was useful for determining the effects of the individual factors and their interactions on the response variables. An acid concentration of 1.09 percent (v/v), a solid:liquid ratio of 1:2.8 (g:ml), and an exposure time of 27 min were established and validated as the optimum pretreatment conditions for ethanol production from hemicellulose hydrolysates of sugar cane bagasse. Under these conditions, a hydrolysate with 50 g/l of xylose, 6.04 g/l of acetic acid, 0.55 g/l of hydroxylmethylfurfural and 0.09 g/l of furfural was obtained and its fermentation yielded roughly 20 g/l of ethanol in 40 hrs.

Sugar cane bagasse as feedstock for second generation ethanol production: part I: diluted acid pretreatment optimization

Tons of sugar cane bagasse are produced in Brazil as waste of the sugar and ethanol industries. This lignocellulosic material is a potential source for second-generation ethanol production. Diluted acid hydrolysis is one of the most efficient pretreatments for hemicellulosic solubilization. The hydrolysate obtained is rich in xylose, which can be converted to ethanol by Pichia stipitis. This work used a statistical approach and the severity factor to investigate the effects of factors associated with the diluted acid hydrolysis process (acid concentration, solid:liquid ratio and time of exposure) on various response variables (xylose concentration, hydrolysis yield, inhibitor concentration and hydrolysate fermentability). The severity factor had a strong influence on the generation of inhibitors. The statistical analysis was useful for determining the effects of the individual factors and their interactions on the response variables. An acid concentration of 1.09 percent (vv), an S:L ratio of 1:2.8 (g:ml), and an exposure time of 27 min were established and validated as the optimum pretreatment conditions for the generation of hydrolysates with high xylose concentration and low contents of inhibitors. In such conditions, hydrolysate with 50 g/l of xylose was obtained.