Th17 Cell Induction by Adhesion of Microbes to Intestinal Epithelial Cells.

Intestinal Th17 cells are induced and accumulate in response to colonization with a subgroup of intestinal microbes such as segmented filamentous bacteria (SFB) and certain extracellular pathogens. Here, we show that adhesion of microbes to intestinal epithelial cells (ECs) is a critical cue for Th17 induction. Upon monocolonization of germ-free mice or rats with SFB indigenous to mice (M-SFB) or rats (R-SFB), M-SFB and R-SFB showed host-specific adhesion to small intestinal ECs, accompanied by host-specific induction of Th17 cells. Citrobacter rodentium and Escherichia coli O157 triggered similar Th17 responses, whereas adhesion-defective mutants of these microbes failed to do so. Moreover, a mixture of 20 bacterial strains, which were selected and isolated from fecal samples of a patient with ulcerative colitis on the basis of their ability to cause a robust induction of Th17 cells in the mouse colon, also exhibited EC-adhesive characteristics.

The mechanism of fibril formation of a non-inhibitory serpin ovalbumin revealed by the identification of amyloidogenic core regions.

Ovalbumin (OVA), a non-inhibitory member of the serpin superfamily, forms fibrillar aggregates upon heat-induced denaturation. Recent studies suggested that OVA fibrils are generated by a mechanism similar to that of amyloid fibril formation, which is distinct from polymerization mechanisms proposed for other serpins. In this study, we provide new insights into the mechanism of OVA fibril formation through identification of amyloidogenic core regions using synthetic peptide fragments, site-directed mutagenesis, and limited proteolysis. OVA possesses a single disulfide bond between Cys(73) and Cys(120) in the N-terminal helical region of the protein. Heat treatment of disulfide-reduced OVA resulted in the formation of long straight fibrils that are distinct from the semiflexible fibrils formed from OVA with an intact disulfide. Computer predictions suggest that helix B (hB) of the N-terminal region, strand 3A, and strands 4-5B are highly ß-aggregation-prone regions. These predictions were confirmed by the fact that synthetic peptides corresponding to these regions formed amyloid fibrils. Site-directed mutagenesis of OVA indicated that V41A substitution in hB interfered with the formation of fibrils. Co-incubation of a soluble peptide fragment of hB with the disulfide-intact full-length OVA consistently promoted formation of long straight fibrils. In addition, the N-terminal helical region of the heat-induced fibril of OVA was protected from limited proteolysis. These results indicate that the heat-induced fibril formation of OVA occurs by a mechanism involving transformation of the N-terminal helical region of the protein to ß-strands, thereby forming sequential intermolecular linkages.

Maintenance Therapy With Bortezomib and Dexamethasone for Transplant-ineligible Patients With Multiple Myeloma.

Background/Aim: Here, we investigated whether bortezomib as a maintenance therapy affected outcomes in transplant-ineligible patients with multiple myeloma (MM). Patients and Methods: Following induction therapy with bortezomib, maintenance therapy with bortezomib (1.3 mg/m 2 ) and dexamethasone (20 mg) was administered once or twice every 4 weeks until disease progression. The endpoints of this study were time to next treatment and overall survival. Results: Seventy-six newly diagnosed, transplant-ineligible patients were treated with a bortezomib-based regimen; 28 discontinued induction therapy, 27 did not receive maintenance therapy after induction therapy (the non-maintenance group), and 21 did (the maintenance group). In the three groups, the median times to the next required treatment were 3, 14, and 37 months, respectively. The 3-year overall survival rates were 55%, 69%, and 85%, respectively. There were no significant differences in patient characteristics between the non-maintenance and maintenance groups, except for poorer estimated glomerular filtration rates in the maintenance group. Conclusion: Bortezomib maintenance therapy may be a useful option for transplant-ineligible patients with MM.