Therapeutic Cationic Antimicrobial Peptide (CAP) Derived from Fish Aspartic Proteinase Cathepsin D and its Antimicrobial Mechanism

• Published in: International journal of peptide research and therapeutics 2019-03, Vol.25 (1), p.93-105
• Main Authors: Sathyamoorthi, Akila, Kumaresan, Venkatesh, Palanisamy, Rajesh, Pasupuleti, Mukesh, Arasu, Mariadhas Valan, Al-Dhabi, Naif Abdullah, Marimuthu, Kasi, Amin, S. M. Nurul, Arshad, Aziz, Yusoff, Fatimah Md, Arockiaraj, Jesu
• Format: Article
• Language: English
• Subjects: Amino acids; Animal Anatomy; Antimicrobial activity; Antimicrobial agents; Antimicrobial peptides; Aquatic organisms; Aspartic proteinase; Bacteria; Biochemistry; Bioinformatics; Biomedical and Life Sciences; Cathepsin D; Chemical compounds; Fish; Gene expression; Histology; Homology; Infections; Life Sciences; Molecular Medicine; Morphology; Nucleotide sequence; Peptides; Pharmaceutical Sciences/Technology; Pharmacology/Toxicology; Polymer Sciences; Proteinase; Proteins
• ISSN: 1573-3149; 1573-3904
• DOI: 10.1007/s10989-017-9652-y

Aquatic organisms are rich in antimicrobial peptides which play key role against pathogens during infections. Cathepsin is one of immune proteases which have been proven with multiple functions including antimicrobial activity, but their role as antimicrobial peptides has not been elucidated so far in aquatic organisms. This study reports the identification and characterization of antimicrobial peptides from fish cathepsin D. Channa striatus ( Cs ) cathepsin D (Cath D) was identified from its established cDNA library. Multiple sequence alignment was performed to analyze the homology of Cs CathD with other cathepsin. Based on the amino acid propensity scale, two putative antimicrobial regions were identified, synthesized and analyzed for their antimicrobial potency. Gene expression of Cs Cath D and its mRNA pattern upon pathogenic infection was also observed using real time PCR. All the bioinformatics analysis indicated the gene specific characteristic features of Cs Cath D. Cs CathD mRNA expression was highly expressed at 24 h for bacteria ( Aeromonas hydrophila ) and 48 h for fungus ( Aphanomyces invadans ). The Cs Cath D derived CAPs namely, PL12 and NM12 showed their commendable inhibition towards Bacillus mycoides of the tested bacteria. The cell membrane disruption was observed with PL12 against B. mycoides in flow cytometer. With all proceedings, it is possible to conclude that Cs CathD might be a potent immuno modulator and the reported CAPs could be developed as therapeutic agents to treat bacterial pathogenic infections.