Actin-Resistant DNase1L2 as a Potential Therapeutics for CF Lung Disease

Abstract

In cystic fibrosis (CF), the accumulation of viscous lung secretions rich in DNA and actin is a major cause of chronic inflammation and recurrent infections leading to airway obstruction. Mucolytic therapy based on recombinant human DNase1 reduces CF mucus viscosity and promotes airway clearance. However, the marked susceptibility to actin inhibition of this enzyme prompts the research of alternative treatments that could overcome this limitation. Within the human DNase repertoire, DNase1L2 is ideally suited for this purpose because it exhibits metal-dependent endonuclease activity on plasmid DNA in a broad range of pH with acidic optimum and is minimally inhibited by actin. When tested on CF artificial mucus enriched with actin, submicromolar concentrations of DNase1L2 reduces mucus viscosity by 50% in a few seconds. Inspection of superimposed model structures of DNase1 and DNase1L2 highlights differences at the actin-binding interface that justify the increased resistance of DNase1L2 toward actin inhibition. Furthermore, a PEGylated form of the enzyme with preserved enzymatic activity was obtained, showing interesting results in terms of activity. This work represents an effort toward the exploitation of natural DNase variants as promising alternatives to DNase1 for the treatment of CF lung disease.

Structural features of Dnase1L3 responsible for serum antigen clearance

“…Dnase1L3 is naturally resistant to actin inhibition, in part, due to Phe-134 that disrupts the "central hydrophobic interface" with actin in Dnase1 12,25 . A similar mechanism of actin resistance was proposed for Dnase1L2 46 . Other determinants for actin resistance in Dnase1L3 include the disruption of stabilizing salt-bridged networks needed for actin binding to Dnase1, and the electrostatic repulsion of actin at the binding interface.…”

Dnase1 Family in Autoimmunity

“…Recombinant Dnase1 is administered in CF patients to improve mucociliary clearance and pulmonary function [89][90][91]. Dnase1L2 is under development as a next-generation treatment for CF [92]. Beyond CF, Dnase1 has been tested in other pulmonary diseases, including asthma, obstructive pulmonary disease, chronic pulmonary diseases, and hemorrhagic shock [93][94][95].…”

Pathological Significance of Macrophages in Erectile Dysfunction Including Peyronie’s Disease

“…As these macrophages were isolated from the lungs of cystic fibrosis-model mice, the authors suggested that macrophages were the target effector cells of the anti-inflammatory effects of vardenafil [ 95 ]. The pathogenesis and progression of cystic fibrosis are regulated by many factors, such as microbial infection, cytokines, enzymes, and gene mutations [ 94 , 96 , 97 , 98 ]. In addition, PDE5 can affect these pathogenic activities in cystic fibrosis in various organs in a macrophage-independent manner [ 94 , 95 , 99 , 100 ].…”