Page 20 - F. Cell biology
P. 20
[F. Cell biology-13]
A novel peptide oligomer of bacitracin induces M1
macrophage polarization by facilitating Ca2+ influx in
macrophage-like RAW 264.7 cells
Seon Yeong Ji¹˙², Hyesook Lee¹˙², Hyun Hwang-Bo¹˙², Su-Hyun Hong¹˙², Hee-Jae Cha³, Cheol Park⁴,
Suhkmann Kim⁵, Heui-Soo Kim⁶, Yung Hyun Choi¹˙²˙*
¹Biochemistry, Dong-eui University College of Korean medicine, Busan 47227, Republic of Korea, ²Anti-Aging
Research Center, Dong-eui University, Busan 47340, Republic of Korea, ³Parasitology and Genetics, Kosin University
College of Medicine, Busan 49267, Republic of Korea, ⁴Basic Sciences, College of Liberal Studies, Dong-eui
University, Busan 47340, Republic of Korea, ⁵Chemistry, Pusan National University, Busan 46241, Republic of
Korea, ⁶Biological Sciences, Pusan National University, Busan 46241, Republic of Korea
Antimicrobial peptides (AMPs) are components of the innate immune system and form the first defense against
pathogens for various organisms. In the present study, we assessed whether CSP32, a novel AMP oligomer of
bacitracin isolated from a strain of Bacillus spp., regulates the polarization of RAW 264.7 cells. CSP32 stimulated
phagocytosis while inducing the appearance of the typical M1 macrophage phenotype; these macrophages play a
role in host defense against pathogens. Furthermore, our results showed that CSP32 enhanced the expression of
pro-inflammatory mediators, such as cytokines, chemokines and chemokine ligands. In addition, the CSP32-
stimulated inflammatory mediators were induced by the mitogen-activated protein kinase/nuclear factor kappa B
(MAPK/NF-κB) signaling pathway during M1 macrophage polarization. In particular, CSP32 increased the numbers
of Ca2+-positive macrophages while upregulating PLCr1 and PKCε. Furthermore, the inhibition of intracellular Ca2+
by BAPTA-AM, a Ca2+ chelator, suppressed the CSP32-mediated phagocytosis, inflammatory mediator production
and NF-κB activation. In conclusion, our data suggested that CSP32-stimulated M1 macrophage polarization is
dependent on the Ca2+ signaling pathway and may result in enhanced immune capacities.
