Selection and Characterization of Probiotic Bacteria Exhibiting Antiadipogenic Potential in 3T3-L1 Preadipocytes

Abstract

Abnormal adipocyte growth, distinguished by an increase in cell numbers and cellular differentiation, is regarded as a major pathological characteristic of obesity. Thus, inhibition of adipogenic differentiation in adipocytes could prevent obesity. Recently, certain probiotic stains have been reported to regulate lipid metabolism in vitro and/or in vivo. In this backdrop, this study aimed to investigate basic probiotic properties and potential antiobesity characteristics of mouse 3T3-L1 preadipocytes. Six lactic acid bacteria (LAB) strains were prescreened for their cholesterol-lowering activity, antioxidant activity, and survival at low pH and in a solution containing bile salts. These six strains were investigated for antiadipogenic activity by employing 3T3-L1 mouse preadipocytes. 3T3-L1 cells were treated with selected strains during the differentiation process. Lactobacillus johnsonii 3121 and Lactobacillus rhamnosus 86 were found to be more capable of reducing triglyceride and lipid accumulation, as compared to control group, which are fully differentiated 3T3-L1 adipocytes. These strains also inhibited adipocyte differentiation by downregulating the adipogenic transcription factor in 3T3-L1 adipocytes. Taken together, these results indicate that L. johnsonni 3121 and L. rhamnosus 86 could potentially act as probiotic bacteria and prevent fat accumulation by regulating adipogenesis-related markers.

Keywords: 3T3-L1 preadipocytes; Adipogenesis; Lactic acid bacteria; Obesity; Probiotics.

Fig. 1

Acid tolerance of the 61 LAB strains sorted according to decreasing overall survivability. a Top 1 to 20. b Top 21 to 40. c Remaining 41 to 61. Results are expressed as mean ± SE (n = 3)

Fig. 2

Bile tolerance of the LAB strains sorted by decreasing overall survivability. a Top 1 to 20. b top 21 to 40. c Remaining 41 to 61. Results are expressed as mean ± SE (n = 3)

Fig. 3

Cholesterol-lowering activities of the 61 LAB strains sorted by decreasing reduction rate. a Top 1 to 20. b Top 21 to 40. c Remaining 41 to 61. Results are expressed as mean ± SE (n = 3)

Fig. 4

Antioxidant activities of the 61 LAB strains sorted according to decreasing DPPH scavenging activity. a Top 1 to 20. b Top 21 to 40. c Remaining 41 to 61. Results are expressed as mean ± SE (n = 3)

Fig. 5

Cytotoxicity of the six probiotic candidates on 3T3-L1 cells. Results are expressed as mean ± SE (n = 3). Lowercase superscript letters (a, b) denote significantly different mean values in the same series (P < 0.05)

Fig. 6

Effects of the six probiotic candidates on triglyceride (TG) and lipid accumulation in 3T3-L1 cells. a TG accumulation in differentiated mature 3T3-L1 adipocytes. b Quantification of stained lipids with oil red O in differentiated mature 3T3-L1 adipocytes. c Lipid accumulation in differentiated mature 3T3-L1 adipocytes stained by oil red O. The red dot indicates the accumulated lipid. It can be seen that heat-killed L. johnsonii 3121 and L. rhamnosus 86 administrated cells have significantly less red areas overall. (× 100 magnification). Results are expressed as mean ± SE (n = 6). Lowercase superscript letters (a, b, c) denotes significantly different mean values in the same series (P < 0.05)

Fig. 7

Effect of L. rhamnosus 86 and L. johnsonii 3121 on mRNA expression levels of adipogenesis-related markers (peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein α (C/EBPα), and adipocyte protein 2 (aP2)) in 3T3-L1 cells. Results are expressed as mean ± SE (n = 6). Lowercase superscript letters (a, b, c) denote significantly different mean values in the same series (P < 0.05)

Fig. 8

Experimental design of the selection strategy employed for identifying probiotics with antiobesity properties