Sodium butyrate modulates chicken macrophage proteins essential for Salmonella Enteritidis invasion

Abstract

Salmonella Enteritidis is an intracellular foodborne pathogen that has developed multiple mechanisms to alter poultry intestinal physiology and infect the gut. Short chain fatty acid butyrate is derived from microbiota metabolic activities, and it maintains gut homeostasis. There is limited understanding on the interaction between S. Enteritidis infection, butyrate, and host intestinal response. To fill this knowledge gap, chicken macrophages (also known as HTC cells) were infected with S. Enteritidis, treated with sodium butyrate, and proteomic analysis was performed. A growth curve assay was conducted to determine sub-inhibitory concentration (SIC, concentration that do not affect bacterial growth compared to control) of sodium butyrate against S. Enteritidis. HTC cells were infected with S. Enteritidis in the presence and absence of SIC of sodium butyrate. The proteins were extracted and analyzed by tandem mass spectrometry. Our results showed that the SIC was 45 mM. Notably, S. Enteritidis-infected HTC cells upregulated macrophage proteins involved in ATP synthesis through oxidative phosphorylation such as ATP synthase subunit alpha (ATP5A1), ATP synthase subunit d, mitochondrial (ATP5PD) and cellular apoptosis such as Cytochrome-c (CYC). Furthermore, sodium butyrate influenced S. Enteritidis-infected HTC cells by reducing the expression of macrophage proteins mediating actin cytoskeletal rearrangements such as WD repeat-containing protein-1 (WDR1), Alpha actinin-1 (ACTN1), Vinculin (VCL) and Protein disulfide isomerase (P4HB) and intracellular S. Enteritidis growth and replication such as V-type proton ATPase catalytic subunit A (ATPV1A). Interestingly, sodium butyrate increased the expression of infected HTC cell protein involving in bacterial killing such as Vimentin (VIM). In conclusion, sodium butyrate modulates the expression of HTC cell proteins essential for S. Enteritidis invasion.

Fig 1. Effect of S. Enteritidis on the proteome of HTC cells.

S. Enteritidis infection in HTC cells induced down and upregulated proteins in different biological processes. HTC cells were treated with S. Enteritidis for 4 h, proteins were extracted and analyzed by tandem mass spectrometry. Differentially expressed proteins were calculated using Scaffold software (P<0.05) and biological processes were predicted by using STRING and PANTHER software.

Fig 2. Effect of sodium butyrate on the proteome of HTC cells infected with S. Enteritidis.

Sodium butyrate treatment in S. Enteritidis infected HTC cells induced down and upregulated proteins in different biological processes. HTC cells were treated with S. Enteritidis for 4 h in the presence and absence of sodium butyrate, proteins were extracted and analyzed by tandem mass spectrometry. Differentially expressed proteins were calculated using Scaffold software (P<0.05) and biological processes were predicted by using STRING and PANTHER software.