The overall composition of the mammalian intestinal microbiota varies between individuals: within each individual there are differences along the length of the intestinal tract related to host nutrition, intestinal motility and secretions. Mucus is a highly regenerative protective lubricant glycoprotein sheet secreted by host intestinal goblet cells; the inner mucus layer is nearly sterile. Here we show that the outer mucus of the large intestine forms a unique microbial niche with distinct communities, including bacteria without specialized mucolytic capability. Bacterial species present in the mucus show differential proliferation and resource utilization compared with the same species in the intestinal lumen, with high recovery of bioavailable iron and consumption of epithelial-derived carbon sources according to their genome-encoded metabolic repertoire. Functional competition for existence in this intimate layer is likely to be a major determinant of microbiota composition and microbial molecular exchange with the host.

Hydrodynamic delivery has emerged as the simplest and most effective method for intracellular delivery of membrane impermeable substances in rodents. The system employs a physical force generated by a rapid injection of large volume of solution into a blood vessel to enhance the permeability of endothelium and the plasma membrane of the parenchyma cells to allow delivery of substance into cells. The procedure was initially established for gene delivery in mice and its applications have been extended to the delivery of proteins, oligo nucleotides, genomic DNA and RNA sequences, and small molecules. The focus of this review is on applications of hydrodynamic delivery in pharmaceutical research. Examples are provided to highlight the use of hydrodynamic delivery for study of transcriptional regulation of CYP enzymes, for establishment of animal model for viral infections, and for gene drug discovery and gene function analysis.

Excessive apoptosis of disc cells is believed to play an important role in intervertebral disc (IVD) degeneration. It has been shown that interleukin-1beta (IL-1beta) is involved in the failure of disc matrix by suppressing the synthesis of matrix components and stimulating the expression of matrix metalloproteinases. However, whether IL-1beta induces disc cell apoptosis is still unclear. The objective of this study was to investigate the effect of IL-1beta on the apoptosis of rat annular cells cultured with or without serum supplement. First-passage rat annular cells were cultured with 0% or 10% fetal bovine serum (FBS) supplement and stimulated with 0, 10, 20 or 50 ng/ml IL-1beta for 12, 24 or 48 h. Apoptotic incidences were quantified by flow cytometry, morphologic changes in apoptotic cells were visualized by Hoechst 33258 staining and phase-contrast microscopy, and caspase-3 activity was also determined. When rat annular cells were cultured with 10% FBS supplement, no significant changes in apoptotic incidences, apoptotic morphology and caspase-3 activity were observed even when cells were stimulated with 50 ng/ml IL-1beta for 48 h. In contrast, serum deprivation for 24 h led to an increase in apoptotic incidences, the number of apoptotic nuclei and caspase-3 activity, and IL-1beta significantly increased the effects of serum deprivation in a dose-dependent manner. Our results indicate that IL-1beta alone is not a sufficient stimulus to induce disc cell apoptosis and that in order to suppress disc cell apoptosis, improving the nutrient supply to the disc may be more effective than antagonizing the adverse effects of IL-1beta.

Tight control of cell-cycle progression is critical for T-lymphocytes to function properly. Slfn1 (Schlafen1) has been reported to play an important role in the establishment and maintenance of quiescence in T-lymphocytes. However, how Slfn1 accomplishes this critical function remains poorly understood. In the present study, we show that nuclear localization is a prerequisite for Slfn1 to induce cell-cycle arrest, with DnaJB6, identified as a new Slfn1-binding protein, playing a pivotal role in this process. DnaJB6, a chaperone protein of the DnaJ/Hsp (heat-shock protein) 40 family, stabilizes Slfn1 together with its partner Hsp70, and, more importantly, it enhances the nuclear import of Slfn1. Overexpression of DnaJB6 was found to increase Slfn1 nuclear accumulation and resulted in cell-cycle arrest, whereas, in DnaJB6 knock-down cells, Slfn1 was mainly sequestered in the cytoplasm and no cell-cycle arrest was observed. Furthermore, transgenic expression of DnaJB6 in T-lineage cells inhibited Slfn1's degradation, promoted its nuclear import and ultimately led to suppression of T-cell proliferation upon TCR (T-cell receptor) activation. In addition, DnaJB6 increased Slfn1's effect on its downstream target cyclin D1 in co-transfected cells. Altogether, our results demonstrate that DnaJB6 is necessary for translocation of Slfn1 into the nucleus, where Slfn1 down-regulates cyclin D1, induces cell-cycle arrest and programmes a quiescent state of T-cells.