The core motivation behind our project is the ongoing battle against Invasive Fungal Infections (IFIs) in India. The risks posed by opportunistic fungal infections, especially to immunocompromised patients, have been brought into light following the COVID-19 pandemic in the country. Opportunistic fungal infections like mucormycosis, aspergillosis, and candidiasis have ravaged immunocompromised patients battling multiple comorbidities. Tackling these infections has proven difficult due to a limited repertoire of antifungal drugs, their costs, drug interactions, the routes of administration, and side effects like nephrotoxicity. Furthermore, the rampant use of these limited drugs raises the alarming possibility of developing drug-resistant fungal strains.
We chose to target chitin (a long-chain polymer of N-acetylglucosamine), an essential component of the cell walls of all fungal species, notably absent in eukaryotic cells such as our own. Our molecular weapons- ‘chitinases’ are naturally occurring enzymes known to break down the glycosidic bonds in chitin. These are often found in bacteria, yeasts, plants, actinomycetes, arthropods, and humans, which use them as defensive mechanisms against fungal infections. However, given the diversity in fungal species and chitinase enzymes, selecting the appropriate chitinase on a case-to-case basis would be quite difficult. Our goal is to harness the power of these naturally occurring chitinase enzymes by combining their substrate specificities and potentially even activity through active pairings of their functional domains. As a result, we suggest the production of a specified set of recombinant chitinase enzymes that combine the best characteristics of different wild-type enzymes and are thus more effective.
Importantly, the chitin biosynthesis pathway in fungi is rather complex and involves the concerted action of several enzymes in a well-regulated fashion. Hence, we hypothesize that the probability of alteration of chitin structure by the target organisms to avoid lysis by our chitinases is rather low. The recombinant proteins are supported by a thorough literature review that demonstrates the project's viability. Therefore, we are developing a novel, eco-friendly and novel therapeutic ‘MOLDEMORT’ to tackle various invasive fungal infections. This solution has potential wide-ranging applications in healthcare, agriculture, and society alike.
The project idea surfaced when we discovered fungal contamination in a number of sites both on and off-campus. More research into pathogenic fungus species found that Fusarium sp. (causes eye infections), Rhizopus sp. (causes mucormycosis), and Aspergillus sp. (causes aspergillosis) are common in many public areas and frequently cause problems in immunocompromised individuals. Armed with this information on the pathogenic nature of certain fungal species, we decided to isolate fungal samples within the campus and sequenced their genomes to know which species of fungi usually thrive on walls of the building. We found Aspergillus versicolor, Aspergillus niger , Rhizopus oryzae, Fusarium solani , Nodulisporium indicum, Phanerochaete sordida, and unidentified Trichoderma species.
We then grew interested in the question of how fungal infections caused by these species and others could be treated. A survey of literature revealed that the current antifungals used for treatment include various compounds such as amphotericin B (AmB), caspofungin, triazoles, etc., but these antifungal agents have severe limitations due to lack of sufficient fungicidal effect and toxic side effects. Along with this, there have also been several reports of the emergence of drug-resistant fungal strains due to the limited molecular targets of the existing drugs.
We decided to step in and try to create a new antifungal drug that targets the polymer chitin, a ubiquitous component of fungal cell walls. According to the literature survey, the lysis of chitin contained in fungal cell walls by naturally occurring chitinase enzymes would undermine the integrity of fungal cells, leading to their death. By harnessing the power of synthetic biology and protein engineering, the team IISER_TVM has engineered a chimeric chitinase to tackle the issue of invasive fungal infections.
- Ambati et. al. "Dectin-1-Targeted Antifungal Liposomes Exhibit Enhanced Efficacy | Msphere". Msphere, 2021,
- Kainz, Katharina et al. "Fungal Infections In Humans: The Silent Crisis". Microbial Cell, vol 7, no. 6, 2020, pp. 143-145. Shared Science Publishers OG, doi:10.15698/mic2020.06.718. Accessed 19 Aug 2021.
- Bongomin, Felix et al. "Global And Multi-National Prevalence Of Fungal Diseases—Estimate Precision". Journal Of Fungi, vol 3, no. 4, 2017, p. 57. MDPI AG, doi:10.3390/jof3040057. Accessed 19 Aug 2021.