Essential Role of Pre–B-Cell Colony Enhancing Factor in Ventilator-induced Lung Injury

Abstract

Rationale: We previously demonstrated pre-B-cell colony enhancing factor (PBEF) as a biomarker in sepsis and sepsis-induced acute lung injury (ALI) with genetic variants conferring ALI susceptibility. Objectives: To explore mechanistic participation of PBEF in ALI and ventilator-induced lung injury (VILI). Methods: Two models of VILI were utilized to explore the role of PBEF using either recombinant PBEF or PBEF 1/2 mice. Measurements and Main Results: Initial in vitro studies demonstrated recombinant human PBEF (rhPBEF) as a direct rat neutrophil chemotactic factor with in vivo studies demonstrating marked increases in bronchoalveolar lavage (BAL) leukocytes (PMNs) after intratracheal injection in C57BL/6J mice. These changes were accompanied by increased BAL levels of PMN chemoattractants (KC and MIP-2) and modest increases in lung vascular and alveolar permeability. We next explored the potential synergism between rhPBEF challenge (intratracheal) and a model of limited VILI (4 h, 30 ml/kg tidal volume) and observed dramatic increases in BAL PMNs, BAL protein, and cytokine levels (IL-6, TNF-a, KC) compared with either challenge alone. Gene expression profiling identified induction of ALI-and VILI-associated gene modules (nuclear factor-kB, leukocyte extravasation, apoptosis, Toll receptor pathways). Heterozygous PBEF 1/2 mice were significantly protected (reduced BAL protein, BAL IL-6 levels, peak inspiratory pressures) when exposed to a model of severe VILI (4 h, 40 ml/kg tidal volume) and exhibited significantly reduced expression of VILIassociated gene expression modules. Finally, strategies to reduce PBEF availability (neutralizing antibody) resulted in significant protection from VILI. Conclusions: These studies implicate PBEF as a key inflammatory mediator intimately involved in both the development and severity of ventilator-induced ALI.

Role of type 2 deiodinase in response to acute lung injury (ALI) in mice

“…2A). Retrospective review of our prior expression profiling results in murine models of VILI indicated that D2 mRNA was induced in VILIchallenged WT mice (9.5-fold increase at 30 mL/kg tidal volume and 26.2-fold increase at 40 mL/kg tidal volume) (36,37).…”

“…Groups of mice (WT, n = 8 mice per group; D2KO, n = 6 mice per group; D1KO, n = 6 mice per group; hypothyroid WT mice, n = 6 mice per group) were allocated randomly to either the SB or VILI treatment as previously described (36,37). Mechanical ventilation experiments were performed in age-matched males after anesthesia with inhaled isofluorane followed by i.p.…”

“…ketamine/xylazine. Mice were intubated (20-gauge catheter) and placed on mechanical ventilation (Harvard Apparatus) at room air, tidal volume of 40 mL/kg, 65 breaths/min, and positive end expiratory pressure of 0 cm H 2 O for 4 h, as previously described (36). Ventilated animals were monitored with intermittent blood pressure, arterial blood gas, and body temperature monitoring to ensure adequate perfusion and received 8 mL/kg 0.9% saline at the initiation of ventilation and 2 h after the onset of ventilation.…”

“…Total RNA was isolated from whole lungs of VILI-challenged and SB mice (six to eight mice per group) for expression profiling as previously described (36). Transcript levels of Serpina 3G, Mmp9, Hsp1, Remlγ, mouse chemokines and cytokines IL-1β, IL-6, Cxcl2, Cxcl1, and TNF-α, and deiodinases D1, D2, and D3 were measured by qPCR in 96-well microtiter plates with an ABI Prism 7700 Sequence Detector System (Applied Biosystems).…”

Nicotinamide Phosphoribosyltransferase in Sepsis

“…NAMPT expression also affected the expression of two other inflammatory cytokines (IL-16 and CCR3 genes) [22,23]. Hong et al [24] demonstrated recombinant human NAMPT as a direct rat neutrophil chemotactic factor in in vitro studies. They also demonstrated a marked increase in bronchoalveolar lavage leukocytes after the intratracheal injection of rhNAMPT into C57BL/6J mice.…”