TmPGRP-SA regulates Antimicrobial Response to Bacteria and Fungi in the Fat Body and Gut of Tenebrio molitor

• Published in: International journal of molecular sciences 2020-03, Vol.21 (6), p.2113
• Main Authors: Keshavarz, Maryam, Jo, Yong Hun, Edosa, Tariku Tesfaye, Bae, Young Min, Han, Yeon Soo
• Format: Article
• Language: English
• Subjects: Amino acids; Antiinfectives and antibacterials; Antimicrobial agents; antimicrobial peptide; Antimicrobial peptides; Bacteria; Binding sites; Candida albicans; Escherichia coli; expression pattern; Fat body; Fruit flies; Functional analysis; Fungi; Gene expression; Gram-positive bacteria; Hemocytes; Immune response; Insects; nuclear factor κb; Pathogens; Peptides; Peptidoglycans; Phylogenetics; Proteins; Staphylococcus aureus; Tenebrio molitor; tmpgrp-sa
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms21062113

Antimicrobial immune response is mediated by a signal-transducing sensor, peptidoglycan recognition protein-SA (PGRP-SA), that can recognize non-self molecules. Although several studies have focused on the involvement of Drosophila PGRP-SA in antimicrobial peptide (AMP) expression in response to infections, studies on its role in Tenebrio molitor are lacking. Here, we present a functional analysis of T. molitor PGRP-SA (TmPGRP-SA). In the absence of microbes, TmPGRP-SA was highly expressed in the late-larval fat body, followed by hemocytes, and gut. Interestingly, following Escherichia coli, Staphylococcus aureus, and Candida albicans infections, the mRNA level of TmPGRP-SA was significantly upregulated in both the fat body and gut. TmPGRP-SA silencing had a significant effect on the mortality rates for all the microbes tested. Moreover, TmPGRP-SA is required for regulating the expression of eight AMP genes namely TmTenecin-1, -2, and -4; TmDefensin-1 and -2; TmColeoptericin-1; and TmAttacin-1b and -2 in the fat body in response to E. coli and S. aureus infections. TmPGRP-SA is essential for the transcription of TmTenecin-2, -4; TmDefensin-2; TmColeoptericin-1, -2; and TmAttacin-1a, -1b, and -2 in the gut upon E. coli and C. albicans infections. However, TmPGRP-SA does not regulate AMP expression in the hemocytes. Additionally, TmDorsal isoform X2, a downstream Toll transcription factor, was downregulated in TmPGRP-SA-silenced larval fat body following E. coli and S. aureus challenges, and in the gut following E. coli and C. albicans challenges.