Therapeutic Potential of Novel Mastoparan-Chitosan Nanoconstructs Against Clinical MDR Acinetobacter baumannii: In silico, in vitro and in vivo Studies

Abstract

Afreenish Hassan,1 Aamer Ikram,1 Abida Raza,2 Sidra Saeed,2 Rehan Zafar Paracha,3 Zumara Younas,1 Muhammad Tahir Khadim1 1Department of Microbiology, Armed Forces Institute of Pathology, National University of Medical Sciences, Rawalpindi, Pakistan; 2NILOP Nanomedicine Research Laboratories, National Institute of Lasers and Optronics College, Pakistan Institute of Engineering and Applied Sciences, Islamabad, Pakistan; 3National University of Sciences and Technology, Islamabad, PakistanCorrespondence: Abida RazaNILOP Nanomedicine Research Laboratories, National Institute of Lasers and Optronics College, Pakistan Institute of Engineering and Applied Sciences, Lehtrar Road, Nilore, Islamabad, PakistanTel [phone] ext. 3103, 3177Fax [phone]Email [email protected] HassanDepartment of Microbiology, Armed Forces Institute of Pathology, National University of Medical Sciences, Rawalpindi, PakistanTel [phone] ext. 345Email [email protected]: Acinetobacter baumannii antibiotic resistant infections in high-risk patients are a great challenge for researchers and clinicians worldwide. In an effort to achieve potent bactericidal outcomes, a novel chitosan–mastoparan nanoconstruct (Mast-Cs NC) was designed and assessed for its therapeutic potential through in silico, in vitro and in vivo experimentation against clinical multidrug-resistant (MDR) A. baumannii.Methods: Optimized 3D structures of mastoparan and chitosan were coupled computationally through an ionic cross-linker to generate a circular ring of chitosan encasing mastoparan. The complex was assessed for interactions and stability through molecular dynamic simulation (MDS). Binding pocket analysis was used to assess the protease–peptide interface. Mast-Cs NC were prepared by the ionic gelation method. Mast-Cs NC were evaluated in vitro and in vivo for their therapeutic efficacy against drug-resistant clinical A. baumannii.Results: MDS for 100 ns showed stable bonds between chitosan and mastoparan; the first at chitosan oxygen atom-46 and mastoparan isoleucine carbon atom with a distance of 2.77 Å, and the second between oxygen atom-23 and mastoparan lysine nitrogen atom with a distance of 2.80 Å, and binding energies of − 3.6 and − 7.4 kcal/mol, respectively. Mast-Cs complexes approximately 156 nm in size, with +54.9 mV zeta potential and 22.63% loading capacity, offered > 90% encapsulation efficiency and were found to be geometrically incompatible with binding pockets of various proteases. The MIC90 of Mast-Cs NC was significantly lower than that of chitosan (4 vs 512 μg/mL, respectively, p< 0.05), with noticeable bacterial damage upon morphological analysis. In a BALB/c mouse sepsis model, a significant reduction in bacterial colony count in the Mast-Cs treated group was observed compared with chitosan and mastoparan alone (p< 0.005). Mast-Cs maintained good biocompatibility and cytocompatibility.Conclusion: Novel mastoparan-loaded chitosan nanoconstructs signify a successful strategy for achieving a synergistic bactericidal effect and higher therapeutic efficacy against MDR clinical A. baumannii isolates. The Mast-Cs nano-drug delivery system could work as an alternative promising treatment option against MDR A. baumannii.Keywords: Acinetobacter baumannii, mastoparan, antimicrobial resistance, simulation, chitosan, antimicrobial peptides, therapeutic efficacy, interactions

Keywords

• acinetobacter baumannii
• mastoparan
• antimicrobial resistance
• simulation
• chitosan
• antimicrobial peptides
• therapeutic efficacy
• interactions