Pro-inflammatory effects of commercial alpha-lactalbumin on RAW 264.7 macrophages is due to endotoxin contamination

Lin, I-Chun; Kuo, Cheng‐Deng

doi:10.1016/j.fct.2010.06.034

Cited by 15 publications

(9 citation statements)

References 35 publications

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“…If an unpurified commercial ovalbumin containing LPS was used, endothelial cells were activated in early stages of inflammation [52]. False pro-inflammatory effects of commercial alpha-lactalbumin were previously described in RAW 264.7 macrophages due to endotoxin contamination [53]. And, finally, other authors mentioned contamination of commercial LF [18, 54].…”

Section: Resultsmentioning

confidence: 99%

Bovine lactoferrin free of lipopolysaccharide can induce a proinflammatory response of macrophages

et al. 2016

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BackgroundLactoferrin (LF) is an 80 kDa glycoprotein which is known for its effects against bacteria, viruses and other pathogens. It also has a high potential in nutrition therapy and welfare of people and a variety of animals, including piglets. The ability to bind lipopolysaccharide (LPS) is one of the described anti-inflammatory mechanisms of LF. Previous studies suggested that cells can be stimulated even by LPS-free LF. Therefore, the aim of our study was to bring additional information about this possibility. Porcine monocyte derived macrophages (MDMF) and human embryonic kidney (HEK) cells were stimulated with unpurified LF in complex with LPS and with purified LF without bound LPS.ResultsBoth cell types were stimulated with unpurified as well as purified LF. On the other hand, neither HEK0 cells not expressing any TLR nor HEK4a cells transfected with TLR4 produced any pro-inflammatory cytokine transcripts after stimulation with purified LF. This suggests that purified LF without LPS stimulates cells via another receptor than TLR4. An alternative, TLR4-independent, pathway was further confirmed by analyses of the NF-kappa-B-inducing kinase (NIK) activation. Western blot analyses showed NIK which activates different NFκB subunits compared to LF-LPS signaling via TLR4. Though, this confirmed an alternative pathway which is used by the purified LF free of LPS. This stimulation of MDMF led to low, but significant amounts of pro-inflammatory cytokines, which can be considered as a positive stimulation of the immune system.ConclusionOur results suggest that LF’s ability is not only to bind LPS, but LF itself may be a stimulant of pro-inflammatory pathways.

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Section: Resultsmentioning

confidence: 99%

Bovine lactoferrin free of lipopolysaccharide can induce a proinflammatory response of macrophages

et al. 2016

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“…Endotoxin is known to induce potent pro‐inflammatory responses in vitro (Lin and Kuo, ). Furthermore, studies have shown that larger sized PM has higher endotoxin content than smaller sized PM.…”

Section: Resultsmentioning

confidence: 99%

Pro‐inflammatory response and oxidative stress induced by specific components in ambient particulate matter in human bronchial epithelial cells

Yang

Liu

Lin

et al. 2014

Environmental Toxicology

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Previous studies have shown that biological effect of particulate matter (PM2.5) is involved in including chemical composition and mass concentration, but the precise components and biological action on human bronchial epithelial cell line (BEAS-2B) are still unclear. The aim of this study was to evaluate the in vitro toxicity of PM2.5 collected at six urban sites in China, and to investigate how particle composition affects cytotoxicity. We used human bronchial epithelial (BEAS-2B) cell lines as model in vitro to expose to PM2.5 from different source, and then reactive oxygen species (ROS), superoxide dismutase activity and total antioxidant capacity were analyzed. Furthermore, we estimated the polycyclic aromatic hydrocarbon (PAH) and transition metal and the endotoxin contents. The mRNA expression of IL-1β and IL-10 following exposure to PM2.5 was measured by QRT-PCR. We also observed the mitochondrial membrane potential (MMP) using JC-1 staining, and apoptosis of BEAS-2B using flow cytometry. In addition, double-stranded DNA breaks (DSBs) were assessed using γ-H2AX immunofluorescence. Our results show that high concentrations of PAHs and elemental Ni were strongly associated with high apoptosis rates and high expression of IL-1β, in addition, Fe element was associated with the ROS level, furthermore, Fe and Cr element were associated with DNA damage in BEAS-2B cells. The cytotoxic effects of urban PM2.5 derived from six different cities in China appear dependent on the specific components in each. Our results indicate that air quality standards based on PM2.5 components may be more relevant than concentration-response functions (CRF). © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 923-936, 2016.

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“…In addition, the protein concentration of our irisin was 0.43 mg/ml, which is about 1720 times the final concentration of 20 nM that we used in the cultures. So, the final concentration of LPS in the irisin added into the cultures was about 0.0028 EU/ml, and even for the 40-nM concentration of irisin, the LPS level was about 0.0056 EU/ml, which was too low to trigger monocytes/ macrophages (24)(25)(26).…”

Section: Function and Lps Test Of R-irisinmentioning

confidence: 97%

Irisin promotes proliferation but inhibits differentiation in osteoclast precursor cells

et al. 2018

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The receptor activator of NF-κB ligand-induced osteoclast differentiation has a critical role in the process of bone metabolism. Overactivation of osteoclastogenesis may result in a series of diseases. Irisin, a novel myokine, which was first reported in 2012, has been proposed to mediate the beneficial metabolic effects of exercise. Studies have demonstrated that irisin targets osteoblasts by promoting osteoblast proliferation and differentiation; however, the underlying mechanism regarding the effect of irisin on osteoclasts remains elusive. Using 2 types of osteoclast precursor cells, RAW264.7 cells and mouse bone marrow monocytes, we showed that irisin promoted osteoclast precursor cell proliferation but inhibited osteoclast differentiation. Irisin down-regulated the expression of osteoclast differentiation marker genes, including receptor activators of NF-κB, nuclear factor of activated T cells, cytoplasmic 1, cathepsin K, and tartrate-resistant acid phosphatase (TRAP), as well as decreasing the number of TRAP-positive multinucleated cells and hydroxyapatite resorption pits. Furthermore, we showed that irisin suppressed the NF-κB signaling pathway, but activated the p38 and JNK signaling pathways. In the presence of an inhibitor of p38 and JNK, irisin-induced promotion of RAW264.7 cell proliferation was attenuated. However, irisin-induced inhibition of osteoclast differentiation was not affected by either the p38 or JNK signaling pathway. Our study suggested the direct effect of irisin on osteoclastogenesis and revealed the mechanism responsible for the therapeutic potential of irisin in bone metabolism disease.-Ma, Y., Qiao, X., Zeng, R., Cheng, R., Zhang, J., Luo, Y., Nie, Y., Hu, Y., Yang, Z., Zhang, J., Liu, L., Xu, W., Xu, C. C., Xu, L. Irisin promotes proliferation but inhibits differentiation in osteoclast precursor cells.

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Pro-inflammatory effects of commercial alpha-lactalbumin on RAW 264.7 macrophages is due to endotoxin contamination

Cited by 15 publications

References 35 publications

Bovine lactoferrin free of lipopolysaccharide can induce a proinflammatory response of macrophages

Bovine lactoferrin free of lipopolysaccharide can induce a proinflammatory response of macrophages

Pro‐inflammatory response and oxidative stress induced by specific components in ambient particulate matter in human bronchial epithelial cells

Irisin promotes proliferation but inhibits differentiation in osteoclast precursor cells

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