Small Molecule Inhibitor Adjuvant Surfactant Therapy Attenuates Ventilator- and Hyperoxia-Induced Lung Injury in Preterm Rabbits.

Pragnya Das,John Ramirez,Beamon Agarwal,Tore Curstedt,Fabrizio Salomone,Nicola Pelizzi,Costanza Casiraghi,Mansoor A Syed,Varsha M Prahaladan,Vineet Bhandari,Shreya Bhandari

doi:10.3389/fphys.2020.00266

Abstract

BackgroundInvasive mechanical ventilation (IMV) has become one of the mainstays of therapy in NICUs worldwide, as a result of which premature babies with extremely low birth weight have been able to survive. Although lifesaving, IMV can result in lung inflammation and injury. Surfactant therapy is considered a standard of care in preterm infants with immature lungs. Recently, small molecule inhibitors like siRNAs and miRNAs have been used for therapeutic purposes. Ddit3 (CHOP), Ang2 and miR34a are known to be upregulated in experimental lung injury. We wanted to test whether inhibitors for these molecules (CHOP siRNA, Ang2 siRNA, and miR34a antagomir) if used alone or with a combination with surfactant (Curosurf®) would help in reducing ventilation and hyperoxia-induced injury in an experimental lung injury model.MethodsPreterm rabbits born by cesarean section were intratracheally instilled with the three small molecule inhibitors with or without Curosurf® prior to IMV and hyperoxia exposure. Prior to testing the inhibitors in rabbits, these small molecule inhibitors were transfected in mouse lung epithelial cells (MLE12 and AECII) and delivered to neonatal mouse pups intranasally as a proof of concept that surfactant (Curosurf®) could be used as an effective vehicle for administration of such drugs. Survival, pulmonary function tests, histopathology, immunostaining, quantitative PCR and western blotting were done to see the adjuvant effect of surfactant with these three small molecule inhibitors.ResultsOur data shows that Curosurf® can facilitate transfection of small molecules in MLE12 cells with the same and/or increased efficiency as Lipofectamine. Surfactant given alone or as an adjuvant with small molecule inhibitors increases survival, decreases IMV and hyperoxia-induced inflammation, improves pulmonary function and lung injury scores in preterm rabbit kits.ConclusionOur study shows that Curosurf® can be used successfully as an adjuvant therapy with small molecule inhibitors for CHOP/Ang2/miR34a. In this study, of the three inhibitors used, miR34a inhibitor seemed to be the most promising compound to combat IMV and hyperoxia-induced lung injury in preterm rabbits.

Highlights

The preterm lung is highly susceptible to injury during resuscitation, and chronic invasive mechanical ventilation (IMV)
The results show that the mixture of Curosurf R (CS) and CHOP siRNA was surface active, as CS alone, in vitro (Supplementary Figure S1 and Table 2)
The results show that the mixture of CS and CHOP siRNA was surface active as CS alone, in vitro (Table 2)

Summary

Introduction

The preterm lung is highly susceptible to injury during resuscitation, and chronic invasive mechanical ventilation (IMV). Premature infants are most vulnerable to ventilatorinduced lung injury (VILI) in the period immediately following birth because of their immature lungs with surfactant content that is often deficient and not uniformly ventilated. In the present study we wanted to explore the therapeutic potential of three small molecule inhibitors (CCAAT enhancer-binding protein, i.e., C/EBP homologous protein or CHOP siRNA, Angiopoietin 2 or Ang siRNA and miR34a antagomir/inhibitor or miR34a Inh) as candidates for treating ventilator and hyperoxia-induced lung injury in neonatal patients, born prematurely. We wanted to test whether inhibitors for these molecules (CHOP siRNA, Ang siRNA, and miR34a antagomir) if used alone or with a combination with surfactant (Curosurf R ) would help in reducing ventilation and hyperoxia-induced injury in an experimental lung injury model

Methods

Results

Conclusion