THERAPEUTIC APPLICATIONS OF INNATE IMMUNE MOLECULES AND THEIR DERIVED PEPTIDES FROM AQUATIC ANIMALS

Innate immune system is an evolutionarily conserved form of host defense that gets activated during pathogenic attack subsequently enabling a cascade of downstream effector mechanisms to fight against a broad spectrum of pathogens. In this regard, innate immune molecules have remarkable therapeutic features against pathogenic infections, and, as a consequence, researchers are targeting on those molecules for the development of therapeutics to control infections. Though the research has reached the pharmaceutical industries by developing few drugs, still understanding about those molecules remain poor, especially among aquatic candidates. Moreover, invertebrates and primitive vertebrates such as fish and shellfish are rich in these kinds of molecules since they primarily rely on innate immune molecules.

From this perspective, to understand and identify the key innate immune molecules from them, a comparative transcriptomic approach was carried out between healthy and pathogenic challenged organisms. Transcriptome analysis of freshwater organisms such as snakehead murrel, Channa striatus and giant prawn, Macrobrachium rosenbergii, revealed a wide range of innate immune molecules which are involved in varied functions such as pathogen recognition, antibacterial, antioxidant, apoptosis, protein repair and so on. In C. striatus, more than 60 full length immune genes have been identified with direct immune role and similarly in M. rosenbergii, around 55 full length immune genes were identified. Gene expression analysis revealed that the expression of the identified genes was modulated during bacterial, fungal and viral pathogens. Functional assays with recombinant proteins showed that they have the potential to be used as therapeutic agents during various pathogenic infections. Additionally, we have identified few antimicrobial peptides (AMPs) from both the organisms including naturally available and derived synthetic peptides that showed high potential to be used as antimicrobial agents to treat various pathogenic infections.

The identified AMPs function in a unique mode of action on the bacterial membrane such a way that the pathogens could not develop resistance against those AMPs. Considering the above facts, the identified potential immune molecules could be developed as therapeutic agents to treat pathogenic infections among aquatic candidates.