Lactiplantibacillus plantarum LM1001 Improves Digestibility of Branched-Chain Amino Acids in Whey Proteins and Promotes Myogenesis in C2C12 Myotubes

Abstract

Lactiplantibacillus plantarum is a valuable potential probiotic species with various proven health-beneficial effects. L. plantarum LM1001 strain was selected among ten strains of L. plantarum based on proteolytic activity on whey proteins. L. plantarum LM1001 produced higher concentrations of total free amino acids and branched-chain amino acids (Ile, Leu, and Val) than other L. plantarum strains. Treatment of C2C12 myotubes with whey protein culture supernatant (1%, 2% and 3%, v/v) using L. plantarum LM1001 significantly increased the expression of myogenic regulatory factors, such as Myf-5, MyoD, and myogenin, reflecting the promotion of myotubes formation (p<0.05). L. plantarum LM1001 displayed β-galactosidase activity but did not produce harmful β-glucuronidase. Thus, the intake of whey protein together with L. plantarum LM1001 has the potential to aid protein digestion and utilization.

Keywords: C2C12 myotubes; Lactiplantibacillus plantarum LM1001; branched-chain amino acids; digestibility; myogenesis.

Fig. 1.. Changes in protein concentration after incubation of WPC with various Lactiplantibacillus plantarum strains (A) and their protein digestibility percentage (B).

Reconstituted WPC (5%, w/v) was incubated for 48 h in the presence of individual L. plantarum strains. Bromelain (5 mg/mL) was used as the positive control. Data are shown as the means±SD of three independent experiments. ^a–d Different letters indicate significant difference between groups (p<0.05). ^* p<0.05 and ^*** p<0.001 compared to 0 h protein contents. WPC, whey protein concentrate.

Fig. 2.. Effect of WPC (A) and LP-WPC (B) culture supernatant on cell viability of C2C12 myotubes.

Data are shown as the means±SD of three independent experiments. ^* p<0.05, ^** p<0.01, and ^*** p<0.001 compared to control (open bar). WPC, whey protein concentrate.

Fig. 3.. Effect of LP-WPC medium on myogenic differentiation in C2C12 cells.

(A) Representative images of western blotting. Relative protein expression of (B) Myf-5, (C) MyoD, and (D) myogenin in LP-WPC treated C2C12 cells. Data are shown as the means±SDs of three independent experiments. ^* p<0.05 and ^** p<0.01, compared to control group. WPC, whey protein concentrate; Myf-5, myogenic factor 5 protein; MyoD, myoblast determination factor 1.

Fig. 4.. Effect of WPC medium on myogenic differentiation in C2C12 cells.

(A) Representative images of Western blotting. Relative protein expression of (B) Myf-5, (C) MyoD, and (D) myogenin in WPC treated C2C12 cells. Data are shown as the means±SDs of three independent experiments. WPC, whey protein concentrate; Myf-5, myogenic factor 5 protein; MyoD, myoblast determination factor 1.