Spores from two distinct colony types of the strain Bacillus subtilis PB6 substantiate anti-inflammatory probiotic effects in mice.

BACKGROUND & AIMS: Reducing symptoms of inflammatory bowel diseases (IBD) by dietary supplements represents more than ever an attractive clinical approach. Since the use of spore forming bacteria may offer interesting advantages, the aim of the study was to address the anti-inflammatory potential of Bacillus >subtilis strain PB6 (ATCC - PTA 6737) spores, provided as a powder preparation. METHODS: The immunomodulatory potential of strain PB6 was first characterized in vitro on human immunocompetent cells for both the commercial spore powder (Anaban™) and two phenotypic variants of the vegetative form. Assessment of the in vivo anti-inflammatory capacity of the standard spore powder and a variant spore powder preparation was performed using a mouse model of acute, TNBS-induced colitis. Performance was compared with the drug prednisolone, and was based on blinded macroscopic and histological scores, blood inflammatory markers and measurements of infiltration of mucosal neutrophils. RESULTS: Strain PB6 induced substantial levels of IL-10 but very low levels of IL-12, TNFα and IFNγ on human PBMC. Both spore powders prevented colitis as shown by significant reductions of near all inflammatory read-outs. CONCLUSION: B. subtilis strain PB6, provided as a preparation of spores, shows pre-clinical anti-inflammatory effects, suggesting further evaluation in a clinical intervention trial, e.g. with IBD type patients.

Tissue expression and translational control of rat kynurenine aminotransferase/glutamine transaminase K mRNAs.

Kynurenic acid (KA) is an endogenous glutamate receptor antagonist at the level of the different ionotropic glutamate receptors. One of the enzymes responsible for the production of KA, kynurenine aminotransferase I (KATI), also catalyses the reversible transamination of glutamine to oxoglutaramic acid (GTK, EC 2.6.1.15). The enzyme exists in a cytosolic and in a mitochondrial form because of the presence of two different KATI mRNAs coding for a protein respectively with and without leader sequence targeting the protein into mitochondria. We have cloned from a phage library of rat kidney cDNA four new KATI cDNAs containing different 5' untranslated regions (UTRs). One of the transcripts (+14KATI cDNA) contains an alternative site of initiation of translation. The tissue distribution of the different transcripts was studied by RT-PCR. The study demonstrated that several KATI mRNAs are constitutively expressed in ubiquitous manner, while +14KATI mRNA is present only in kidney. The translational efficiency of the different transcripts was studied in vitro and enzymatic activities were measured in transiently transfected Cos-1 cells. Each KATI mRNA exhibits a different in vitro translational efficiency, which corresponds to different levels of KAT enzymatic activity in transfected cells. Both findings correlate with the predicted accessibility of the ribosomal binding sites of the different mRNAs. The structure of the rat KATI/GTK gene was also studied. The expression of several KATI mRNAs with different 5'UTRs represents an interesting example of transcriptional/translational control on the expression of pyridoxal phosphate (PLP)-dependent aminotransferases.