Bioengineered Lysozyme Reduces Bacterial Burden and Inflammation in a Murine Model of Mucoid Pseudomonas aeruginosa Lung Infection

Abstract

The spread of drug-resistant bacterial pathogens is a growing global concern and has prompted an effort to explore potential adjuvant and alternative therapies derived from nature's repertoire of bactericidal proteins and peptides. In humans, the airway surface liquid layer is a rich source of antibiotics, and lysozyme represents one of the most abundant and effective antimicrobial components of airway secretions. Human lysozyme is active against both Gram-positive and Gram-negative bacteria, acting through several mechanisms, including catalytic degradation of cell wall peptidoglycan and subsequent bacterial lysis. In the infected lung, however, lysozyme's dense cationic character can result in sequestration and inhibition by polyanions associated with airway inflammation. As a result, the efficacy of the native enzyme may be compromised in the infected and inflamed lung. To address this limitation, we previously constructed a charge-engineered variant of human lysozyme that was less prone to electrostatic-mediated inhibition in vitro. Here, we employ a murine model to show that this engineered enzyme is superior to wildtype human lysozyme as a treatment for mucoid Pseudomonas aeruginosa lung infections. The engineered enzyme effectively decreases the bacterial burden and reduces markers of inflammation and lung injury. Importantly, we found no evidence of acute toxicity or allergic hypersensitivity upon repeated administration of the engineered biotherapeutic. Thus, the charge-engineered lysozyme represents an interesting therapeutic candidate for P. aeruginosa lung infections.

Bioengineered lysozyme in combination therapies forPseudomonas aeruginosalung infections

“…20 Lysozyme and Tet009 combination treatments were administered by oropharyngeal aspiration of a 40 μl volume containing both agents. The protocol for animal infection and lysozyme administration was approved by the Institutional Animal Care and Use Committee of the University of Vermont, in accordance with the Association for Assessment and Accreditation of Laboratory Animal Care guidelines.…”

“…26 Using the same protocol as in our previous work, 20 we examined the in vivo efficacy of Tet009 alone (1.5 μg), hLYS combined with Tet009 (100 μg and 1.5 μg, respectively), and 2-3-7 combined with Tet009 (100 μg and 1.5 μg, respectively) (Fig. 3).…”

“…20 We employed a murine model of acute lung infection based on a mucoid (i.e., alginate producing) isolate of P. aeruginosa, an opportunistic pathogen responsible for 8% of all hospital acquired infections in the United States. 21 Our strain, FRD1, was isolated from the lungs of a cystic fibrosis patient, 22 a cohort that invariably suffers from chronic P. aeruginosa infection and would benefit from the availability of novel antibacterial therapies.…”

Endogenous antimicrobial factors in the treatment of infectious diseases

“…Remarkably interesting in vivo studies have been conducted by Teenback et al [40]. They showed a positive effect of lysozyme in the treatment of experimentally generated P. aeruginosa lung infection.…”

Fusion with a cell wall binding domain renders autolysin LytM a potent anti-Staphylococcus aureus agent

“…Fourth are the more promiscuous lysozymes derived from the innate immune systems of higher organisms. For example, human lysozyme has proven to be efficacious in both native and genetically engineered formats (Bhavsar et al , 2010; Bhavsar et al , 2011; Teneback et al , 2013; Griswold et al , 2014). As a whole, these various trans -acting lytic enzymes have yielded promising results and represent a growing field of research.…”