- CFTRinh-172 was purchased from Calbiochem (San Diego, CA, USA). Cholera toxin was purchased from List Biological Laboratories, Inc. (Campbell, CA, USA). DMEM/F-12 cultured medium was purchased from Gibco (Grand Island, NY, USA)
Constitutive androstane receptor (CAR) belonging to the nuclear receptor superfamily plays an important role in the xenobiotic metabolism and disposition. It has been reported that CAR regulates the expression of the ATP-binding cassette (ABC) transporters in the intestine, such as multidrug resistance protein 1 (MDR1) and multidrug resistance-associated protein 2/3 (MRP2 and MRP3). In this study, we investigated the role of CAR in the regulation of cystic fibrosis transmembrane conductance regulator (CFTR)-mediated chloride transport in T84 human colonic epithelial cells and mouse intestinal tissues. Treatments of T84 cell monolayers with specific CAR agonists (CITCO and phenytoin at concentrations of 1 μM and 5 μM, respectively) for 24 h decreased transepithelial Cl− secretion in response to cAMP-dependent agonist. This inhibition was abolished by coincubation of CITCO with a CAR antagonist, CINPA1. We confirmed that an inhibitory effect of CAR agonists was not due to their cytotoxicity. Basolateral membrane permeabilization experiments also revealed that activation of CAR decreased apical Cl− current stimulated by both CPT-cAMP and genistein (a direct CFTR activator). Such activation also reduced both mRNA and protein expression of CFTR. Furthermore, CITCO decreased cholera toxin (CT)-induced Cl− secretion across T84 cell monolayers. In ICR mice, administration of TCPOBOP (3 mg/kgBW), a murine-specific CAR agonist, for 7 days produced significant decreases in CFTR mRNA and protein expressions in intestinal tissues. Interestingly, TCPOBOP also inhibited CT-induced intestinal fluid accumulation in mice. This is the first evidence showing that CFTR was downregulated by CAR activation in the intestine. Our findings suggest that CAR has potential as a new drug target for treatment of condition with hyperactivity/ hyperfunction of CFTR especially secretory diarrheas.
A therapeutic human antibody against the domain 4 of the Bacillus anthracis protective antigen shows protective efficacy in a mouse model
- (Korea). B. anthracis LF was purchased from List Biological Laboratories. 2.2. Cell lines and culture conditions 2.4. Determination of antibody specificity on PA domains. PD1 was purchased from List Biological Laboratories
EAE was induced in female mice (8 to 12 weeks) by subcutaneous injection of MOG35–55 peptide (100μg, CSBio) emulsified in complete Freund’s adjuvant. Pertussis toxin (250ng, List Biologicals) was administered intraperitoneally on the day of and one day after MOG immunization.
Rheumatoid arthritis is characterized by progressive joint inflammation and affects ~1% of the human population. We noted single-nucleotide polymorphisms (SNPs) in the apoptotic cell-engulfment genes ELMO1, DOCK2, and RAC1 linked to rheumatoid arthritis. As ELMO1 promotes cytoskeletal reorganization during engulfment, we hypothesized that ELMO1 loss would worsen inflammatory arthritis. Surprisingly, Elmo1-deficient mice showed reduced joint inflammation in acute and chronic arthritis models. Genetic and cell-biology studies revealed that ELMO1 associates with receptors linked to neutrophil function in arthritis and regulates activation and early neutrophil recruitment to the joints, without general inhibition of inflammatory responses. Further, neutrophils from the peripheral blood of human donors that carry the SNP in ELMO1 associated with arthritis display increased migratory capacity, whereas ELMO1 knockdown reduces human neutrophil migration to chemokines linked to arthritis. These data identify 'noncanonical' roles for ELMO1 as an important cytoplasmic regulator of specific neutrophil receptors and promoter of arthritis.
Functional fluorescence assay of botulinum neurotoxin A in complex matrices using magnetic beads
The extremely toxic botulinum neurotoxin poses a threat for health and food safety, requiring rapid and easy-to-use detection platforms. To meet these requirements, we have explored a novel functional assay format for detection of botulinum neurotoxin serotype A light chain (BoNT/A LC) in complex matrices. The proposed assay utilizes a synthetic peptide designed to mimic the SNAP-25 protein (synaptosomal-associated protein 25) as substrate bound to a superparamagnetic bead and a fluorescent dye. Cleavage of the peptide by BoNT/A LC yields a reduction in fluorescence signal revealing the presence of the BoNT/A LC in the sample matrices tested. The superparamagnetic beads enable efficient separation of the cleaved peptides from food matrices, thereby improving the reliability of responses. Herein, we demonstrate a protocol offering an assay time of 6 h and a LOD of 0.5 nM (25 ng/ml). The proposed protocol is validated using carrot juice and diluted milk pending further improvements in sensitivity and overall assay time. Robustness, cost-effectiveness, low sample volume requirements in conjunction with the possibility of multiplexing for other proteolytic enzymes makes the proposed protocol competitive in comparison with conventional BoNT assays reported elsewhere.
Sephin1, which prolongs the integrated stress response, is a promising therapeutic for multiple sclerosis
- Mice also received intraperitoneal injections of 200ng pertussis toxin (List Biological Laboratories) in sterile phosphate-buffered saline (PBS) immediately after MOG ad- ministration and 48h later. CFA control mice were similarly induced but lacked MOG
Multiple sclerosis is a chronic autoimmune demyelinating disorder of the CNS. Immune-mediated oligodendrocyte cell loss contributes to multiple sclerosis pathogenesis, such that oligodendrocyte-protective strategies represent a promising therapeutic approach. The integrated stress response, which is an innate cellular protective signalling pathway, reduces the cytotoxic impact of inflammation on oligodendrocytes. This response is initiated by phosphorylation of eIF2α to diminish global protein translation and selectively allow for the synthesis of protective proteins. The integrated stress response is terminated by dephosphorylation of eIF2α. The small molecule Sephin1 inhibits eIF2α dephosphorylation, thereby prolonging the protective response. Herein, we tested the effectiveness of Sephin1 in shielding oligodendrocytes against inflammatory stress. We confirmed that Sephin1 prolonged eIF2α phosphorylation in stressed primary oligodendrocyte cultures. Moreover, by using a mouse model of multiple sclerosis, experimental autoimmune encephalomyelitis, we demonstrated that Sephin1 delayed the onset of clinical symptoms, which correlated with a prolonged integrated stress response, reduced oligodendrocyte and axon loss, as well as diminished T cell presence in the CNS. Sephin1 is reportedly a selective inhibitor of GADD34 (PPP1R15A), which is a stress-induced regulatory subunit of protein phosphatase 1 complex that dephosphorylates eIF2α. Consistent with this possibility, GADD34 mutant mice presented with a similar ameliorated experimental autoimmune encephalomyelitis phenotype as Sephin1-treated mice, and Sephin1 did not provide additional therapeutic benefit to the GADD34 mutant animals. Results presented from the adoptive transfer of encephalitogenic T cells between wild-type and GADD34 mutant mice further indicate that the beneficial effects of Sephin1 are mediated through a direct protective effect on the CNS. Of particular therapeutic relevance, Sephin1 provided additive therapeutic benefit when combined with the first line multiple sclerosis drug, interferon β. Together, our results suggest that a neuroprotective treatment based on the enhancement of the integrated stress response would likely have significant therapeutic value for multiple sclerosis patients.