title: Transcriptome analysis of Streptococcus pneumoniae treated with the designed antimicrobial peptides, DM3.
abstract: In our previous studies, we generated a short 13 amino acid antimicrobial peptide (AMP), DM3, showing potent antipneumococcal activity in vitro and in vivo. Here we analyse the underlying mechanisms of action using Next-Generation transcriptome sequencing of penicillin (PEN)-resistant and PEN-susceptible pneumococci treated with DM3, PEN, and combination of DM3 and PEN (DM3PEN). DM3 induced differential expression in cell wall and cell membrane structural and transmembrane processes. Notably, DM3 altered the expression of competence-induction pathways by upregulating CelA, CelB, and CglA while downregulating Ccs16, ComF, and Ccs4 proteins. Capsular polysaccharide subunits were downregulated in DM3-treated cells, however, it was upregulated in PEN- and DM3PEN-treated groups. Additionally, DM3 altered the amino acids biosynthesis pathways, particularly targeting ribosomal rRNA subunits. Downregulation of cationic AMPs resistance pathway suggests that DM3 treatment could autoenhance pneumococci susceptibility to DM3. Gene enrichment analysis showed that unlike PEN and DM3PEN, DM3 treatment exerted no effect on DNA-binding RNA polymerase activity but observed downregulation of RpoD and RNA polymerase sigma factor. In contrast to DM3, DM3PEN altered the regulation of multiple purine/pyrimidine biosynthesis and metabolic pathways. Future studies based on in vitro experiments are proposed to investigate the key pathways leading to pneumococcal cell death caused by DM3.
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.|School of Pharmacy, Faculty of Science, University of Nottingham Malaysia Campus, Semenyih, Selangor, Malaysia.
authors.forename: Cheng-Foh
authors.initials: CF
authors.lastname: Le
authors.affiliation: Sengenics Sdn Bhd, High Impact Research Building, University of Malaya, 50603, Kuala Lumpur, Malaysia.
authors.forename: Ranganath
authors.initials: R
authors.lastname: Gudimella
authors.affiliation: Sengenics Sdn Bhd, High Impact Research Building, University of Malaya, 50603, Kuala Lumpur, Malaysia.
authors.forename: Rozaimi
authors.initials: R
authors.lastname: Razali
authors.affiliation: Department of Trauma and Emergency Medicine, University Malaya Medical Centre, 50603 Kuala Lumpur, Malaysia.
authors.forename: Rishya
authors.initials: R
authors.lastname: Manikam
authors.affiliation: Department of Medical Microbiology, Faculty of Medicine, University of Malaya, Kuala Lumpur, Malaysia.
authors.forename: Shamala Devi
authors.initials: SD
authors.lastname: Sekaran
mesh_terms: D023181:Antimicrobial Cationic Peptides / Q000138:chemical synthesis / Q000494:pharmacology*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics; D004353:Drug Evaluation, Preclinical; D004357:Drug Synergism; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D063990:Gene Ontology; D005798:Genes, Bacterial / Q000187:drug effects; D010403:Penicillin Resistance; D010406:Penicillins / Q000494:pharmacology; D012329:RNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D012333:RNA, Messenger / Q000235:genetics / Q000302:isolation & purification; D017423:Sequence Analysis, RNA; D013296:Streptococcus pneumoniae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D059467:Transcriptome / Q000187:drug effects*
chemical_list: D023181:Antimicrobial Cationic Peptides; D001426:Bacterial Proteins; D010406:Penicillins; D012329:RNA, Bacterial; D012333:RNA, Messenger