Antibiotic-associated diarrhea due to Clostridium difficile (CDAD) is thought to reflect colonization of a disrupted microbial community by the pathogen. We profiled the fecal microbiota of patients with CDAD (both initial and recurrent episodes) by culture-independent phylogenetic analysis of 16S rRNA-encoding gene sequences. Compared with those from control subjects and patients with an initial episode, the fecal communities in patients with recurrent CDAD were highly variable in bacterial composition and were characterized by markedly decreased diversity. Preservation and restoration of the microbial diversity could represent novel strategies for prevention and treatment of recurrent CDAD, which is often recalcitrant to existing therapies.

Huntington's disease (HD), an inherited neurodegenerative disorder, is caused by an expansion of cytosine-adenine-guanine repeats in the huntingtin gene. The aggregation of mutant huntingtin (mtHTT) and striatal cell loss are representative features to cause uncontrolled movement and cognitive defect in HD. However, underlying mechanism of mtHTT aggregation and cell toxicity remains still elusive. Here, to find new genes modulating mtHTT aggregation, we performed cell-based functional screening using the cDNA expression library and isolated IRE1 gene, one of endoplasmic reticulum (ER) stress sensors. Ectopic expression of IRE1 led to its self-activation and accumulated detergent-resistant mtHTT aggregates. Treatment of neuronal cells with ER stress insults, tunicamycin and thapsigargin, increased mtHTT aggregation via IRE1 activation. The kinase activity of IRE1, but not the endoribonuclease activity, was necessary to stimulate mtHTT aggregation and increased death of neuronal cells, including SH-SY5Y and STHdhQ111/111 huntingtin knock-in striatal cells. Interestingly, ER stress impaired autophagy flux via IRE1-TRAF2 pathway, thus enhancing cellular accumulation of mtHTT. Atg5 deficiency in M5-7 cells increased mtHTT aggregation but blocked ER stress-induced mtHTT aggregation. Further, ER stress markers including p-IRE1 and autophagy markers such as p62 were up-regulated exclusively in the striatal tissues of HD mouse models and in HD patients. Moreover, down-regulation of IRE1 expression rescues the rough-eye phenotype by mtHTT in a HD fly model. These results suggest that IRE1 plays an essential role in ER stress-mediated aggregation of mtHTT via the inhibition of autophagy flux and thus neuronal toxicity of mtHTT aggregates in HD.

No abstract

Wharton's jelly is not only one of the most promising tissue sources for mesenchymal stem cells (MSCs) but also a source of natural growth factors. To prove that we can get both natural growth factors and MSCs from Wharton's jelly, we compared cellular characteristics and the level of basic fibroblast growth factor (bFGF) from samples using the explant culture method to those derived from the traditional enzymatic culture method. The levels of bFGF were 27.0 ± 11.7 ng/g on day 3, 15.6 ± 11.1 ng/g on day 6, and decreased to 2.6 ± 1.2 ng/g on day 14. The total amount of bFGF released was 55.0 ± 25.6 ng/g on explant culture. Compared with the traditional enzymatic digestion method, the explant culture method showed a tendency to release higher levels of bFGF in supernatant media for the first week of culture, and the higher cellular yield at passage 0 (4.89 ± 3.2 × 105/g versus 1.75 ± 2.2 × 105/g, P = 0.01). In addition, the genes related to mitosis were upregulated in the explant-derived MSCs.