Genetic and Proteomic Analysis of Factors Affecting Serum Cholesterol Reduction by Lactobacillus acidophilus A4

Abstract

This article identifies novel factors involved in cholesterol reduction by probiotic bacteria, which were identified using genetic and proteomic approaches. Approximately 600 Lactobacillus acidophilus A4 mutants were created by random mutagenesis. The cholesterol-reducing ability of each mutant was determined and verified using two different methods: the o-phthalaldehyde assay and gas chromatographic analysis (GC). Among screened mutants, strain BA9 showed a dramatically diminished ability to reduce cholesterol, as demonstrated by a 7.7% reduction rate, while the parent strain had a more than 50% reduction rate. The transposon insertion site was mapped using inverse PCR (I-PCR), and it was determined using bioinformatic methods that the deleted region contained the Streptococcus thermophilus catabolite control protein A gene (ccpA). In addition, we have shown using two-dimensional gel electrophoresis (2-DE) that several proteins, including a transcription regulator, FMN-binding protein, major facilitator superfamily permease, glycogen phosphorylase, the YknV protein, and fructose/tagatose bisphosphate aldolase, were strongly regulated by the ccpA gene. In addition, in vivo experiments investigating ccpA function were conducted with rats. Rats fed wild-type L. acidophilus A4 showed a greater than 20% reduction in total serum cholesterol, but rats fed BA9 mutant L. acidophilus showed only an approximately 10% reduction in cholesterol. These results provide important insights into the mechanism by which these lactic acid bacteria reduce cholesterol.

Mechanisms of Cholesterol-Lowering Effects of Lactobacilli and Bifidobacteria Strains as Potential Probiotics with Their bsh Gene Analysis

“…In earlier studies conducted with lactic acid bacteria, an increase in the viability of the strains was observed, reaching 20 and 40% ratios in the presence of cholesterol. During assimilation, the bacterial population increased with regard to the time of incubation, indicating that cholesterol was not toxic to growing cells [Ahire et al, 2012;Lee et al, 2010].…”

Hypocholesterolemic and Growth Promoting Effects of <i>Lactobacillus plantarum</i> AK Isolated from a Nigerian Fermented Cereal Product on Rats Fed High Fat Diet

“…Hypercholesterolemia in humans has been shown to play a major role in atherosclerosis, cardiovascular disease, including coronary heart disease and stroke as well as cerebrovascular diseases [2][3][4]. High cholesterol has also been associated with an increased risk of metabolic syndrome symptoms, including abdominal obesity (large waist circumference), hyperglycemia, hypertriacylglycerolemia and hypertension by as much as 3-fold [5].…”

Regulation of plasma lipid profile by lactobacillus fermentum (probiotic strain ME-3 DSM14241) in a randomised controlled trial of clinically healthy adults

“…Pereira et al [35] demonstrated that short-chain fatty acid concentrations, specifically the molar proportion of propionate and/or bile salt deconjugation, comprised the major mechanism involved in the purported cholesterollowering properties of L. fermentum. Lee et al (2010) revealed that several regulatory proteins mediated serum cholesterol reduction by a probiotic strain [36]. Lactic acid bacteria, including L. fermentum strains, could assimilate cholesterol, and thus, lower serum cholesterol levels [37].…”