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John F Engelhardt

Publications and source records attributed to John F Engelhardt.

At least 19 recordsLinked to original sources
PubMed2026

Research updates in cystic fibrosis related diabetes: Understanding pathophysiology, expanding animal and human islet models, and advancing clinical and translational research.

In 2024-2025, the Cystic Fibrosis Foundation (US) and Cystic Fibrosis Trust (UK) hosted an International CFRD Consortium round-table webinar series for basic science, translational, and clinical researchers with the goal of sharpening mechanistic understanding of CFRD pathogenesis and prioritizing therapeutic development. This review summarizes the research priorities identified in the International CFRD Consortium, including (i) further investigation into the role of pancreatic fibrosis, vascular abnormalities, and α-cell dysfunction in the development of CFRD; (ii) the creation and refinement of novel animal and human cell- and tissue-based models to understand the complex interplay of exocrine and endocrine cells in the CF pancreas; (iii) development and validation of circulating and imaging biomarkers, together with dynamic glucose testing to explore β-cell function and kinetics in people with CF across the dysglycemia spectrum; and (iv) prospective clinical studies to guide CFRD treatment options and investigate the changing landscape of aging, increasing prevalence of obesity and diabetes and their complications in the era of cystic fibrosis transmembrane conductance regulator (CFTR) modulators. Collectively, these priorities aim to accelerate transition from mechanism to intervention and expand evidence-based care for people with CF at risk of, or living with, CFRD.

Humans↗
PubMed2015

Ferret and pig models of cystic fibrosis: prospects and promise for gene therapy.

Large animal models of genetic diseases are rapidly becoming integral to biomedical research as technologies to manipulate the mammalian genome improve. The creation of cystic fibrosis (CF) ferrets and pigs is an example of such progress in animal modeling, with the disease phenotypes in the ferret and pig models more reflective of human CF disease than mouse models. The ferret and pig CF models also provide unique opportunities to develop and assess the effectiveness of gene and cell therapies to treat affected organs. In this review, we examine the organ disease phenotypes in these new CF models and the opportunities to test gene therapies at various stages of disease progression in affected organs. We then discuss the progress in developing recombinant replication-defective adenoviral, adeno-associated viral, and lentiviral vectors to target genes to the lung and pancreas in ferrets and pigs, the two most affected organs in CF. Through this review, we hope to convey the potential of these new animal models for developing CF gene and cell therapies.

Animals↗
PubMed2007

Hybrid adeno-associated virus bearing nonhomologous inverted terminal repeats enhances dual-vector reconstruction of minigenes in vivo.

We have previously demonstrated that hybrid adeno-associated viral (AAV) vectors bearing nonhomologous inverted terminal repeats (ITRs) enhance directional intermolecular recombination and the efficiency of dual-AAV vector trans-splicing in cultured cells. Using hybrid-ITR vectors carrying two exons of a lacZ minigene, we demonstrate that this dual-vector approach also mediates higher levels (3- to 6-fold) of gene reconstitution in mouse skeletal muscle, liver, and heart. Inhibition of the proteasome by systemic administration of Doxil (Food and Drug Administration-approved lipid-formulated doxorubicin) further enhanced dual-vector trans-splicing 6- to 12-fold in two mouse strains. Hence, using hybrid-ITR AAV vectors in combination with proteasome modulation enhanced dual-vector delivery of a transgene approximately 36-fold over the current dual-vector trans-splicing approaches. These data provide in vivo evidence that ITR sequence-dependent homologous recombination, rather than nonhomologous end joining, is the predominant mechanism for AAV genome heterodimerization. Hence, enhanced directional recombination provided by hybrid-ITR vectors may be a useful in vivo strategy for improving dual-vector delivery of transgenes larger than the AAV packaging limit.

Animals↗
PubMed2006

Bioelectric properties of chloride channels in human, pig, ferret, and mouse airway epithelia.

The development of effective therapies for cystic fibrosis (CF) requires animal models that can appropriately reproduce the human disease phenotype. CF mouse models have demonstrated cAMP-inducible, non-CF transmembrane conductance regulator (non-CFTR) chloride transport in conducting airway epithelia, and this property is thought to be responsible for the lack of a spontaneous CF-like phenotype in the lung. Thus, an understanding of species diversity in airway epithelial electrolyte transport and CFTR function is critical to developing better models for CF. Two species currently being used in attempts to develop better animal models of CF include the pig and ferret. In the study reported here, we sought to comparatively characterize the bioelectric properties of in vitro polarized airway epithelia--from human, mouse, pig and ferret--grown at the air-liquid interface (ALI). Bioelectric properties analyzed include amiloride-sensitive Na(+) transport, 4,4'-diisothiocyanato-stilbene-2,2'-disulfonic acid (DIDS)-sensitive Cl(-) transport, and cAMP-sensitive Cl(-) transport. In addition, as an index for CFTR functional conservation, we evaluated the ability of four CFTR inhibitors, including glibenclamide, 5-nitro-2-(3-phenylpropyl-amino)-benzoic acid, CFTR (inh)-172, and CFTR(inh)-GlyH101, to block cAMP-mediated Cl(-) transport. Compared with human epithelia, pig epithelia demonstrated enhanced amiloride-sensitive Na(+) transport. In contrast, ferret epithelia exhibited significantly reduced DIDS-sensitive Cl(-) transport. Interestingly, although the four CFTR inhibitors effectively blocked cAMP-mediated Cl(-) secretion in human airway epithelia, each species tested demonstrated unique differences in its responsiveness to these inhibitors. These findings suggest the existence of substantial species-specific differences at the level of the biology of airway epithelial electrolyte transport, and potentially also in terms of CFTR structure/function.

Amino Acid Sequence↗
PubMed2006

Pleiotropic functions of TNF-alpha determine distinct IKKbeta-dependent hepatocellular fates in response to LPS.

TNF-alpha influences morbidity and mortality during the course of endotoxemia. However, the complex pleiotropic functions of TNF-alpha remain poorly understood. We evaluated how hepatic induction of NF-kappaB and TNF-alpha influence survival and hepatocellular death in a lethal murine model of endotoxic shock. Using dominant-negative viral vectors to inhibit the IKK complex, we demonstrate through this study that the liver is a major source of TNF-alpha during the course of lethal endotoxemia and that IKKbeta (but not IKKalpha) is predominantly responsible for activating NF-kappaB and TNF-alpha in the liver after LPS administration. Using TNF-alpha knockout mice and hepatic-specific inhibition of IKKbeta, we demonstrate that the status of TNF-alpha and NF-kappaB balances necrotic and apoptotic fates of hepatocytes in the setting of endotoxemia. In the presence of TNF-alpha, inhibiting hepatic IKKbeta resulted in increased survival, reduced serum proinflammatory cytokines, and reduced hepatocyte necrosis in response to a lethal dose of endotoxin. In contrast, inhibiting hepatic IKKbeta in TNF-alpha knockout mice resulted in decreased survival and increased caspase 3-mediated hepatocyte apoptosis after endotoxin challenge, despite a reduced proinflammatory cytokine response. In the presence of TNF-alpha, NF-kappaB-dependent hepatocellular necrosis predominated, while in the absence of TNF-alpha, NF-kappaB primarily influenced apoptotic fate of hepatocytes. Changes in JNK phosphorylation after LPS challenge were also dynamically affected by both IKKbeta and TNF-alpha; however, this pathway could not solely explain the differential outcomes in hepatocellular fates. In conclusion, our studies demonstrate that induction of NF-kappaB and TNF-alpha balances protective (antiapoptotic) and detrimental (proinflammatory) pathways to determine hepatocellular fates during endotoxemia.

Animals↗
PubMed2006

Unique biologic properties of recombinant AAV1 transduction in polarized human airway epithelia.

The choice of adeno-associated virus serotypes for clinical applications is influenced by the animal model and model system used to evaluate various serotypes. In the present study, we sought to compare the biologic properties of rAAV2/1, rAAV2/2, and rAAV2/5 transduction in polarized human airway epithelia using viruses purified by a newly developed common column chromatography method. Results demonstrated that apical transduction of human airway epithelia with rAAV2/1 was 100-fold more efficient than rAAV2/2 and rAAV2/5. This transduction profile in human airway epithelia (rAAV2/1 >> rAAV2/2 = rAAV2/5) was significantly different from that seen following nasal administration of these vectors to mouse lung (rAAV2/5 > rAAV2/1 >> rAAV2/2), emphasizing differences in transduction of these serotypes between these two species. In stark contrast to rAAV2/2 and rAAV2/5, rAAV2/1 transduced both the apical and basolateral membrane of human airway epithelia with similar efficiency. However, the overall level of transduction across serotypes did not correlate with vector internalization. We hypothesized that differences in post-entry processing of these serotypes might influence the efficiency of apical transduction. To this end, we tested the effectiveness of proteasome inhibitors to augment nuclear translocation and gene expression from the three serotypes. Augmentation of rAAV2/1 apical transduction of human polarized airway epithelia was 10-fold lower than that for rAAV2/2 and rAAV2/5. Cellular fractionation studies demonstrated that proteasome inhibitors more significantly enhanced rAAV2/2 and rAAV2/5 translocation to the nucleus than rAAV2/1. These results demonstrate that AAV1 transduction biology in human airway epithelia differs from that of AAV2 and AAV5 by virtue of altered ubiquitin/proteasome sensitivities that influence nuclear translocation.

Animals↗
PubMed2006

Nox2-containing NADPH oxidase and Akt activation play a key role in angiotensin II-induced cardiomyocyte hypertrophy.

Angiotensin II (ANG II) has profound effects on the development and progression of pathological cardiac hypertrophy; however, the intracellular signaling mechanisms are not fully understood. In this study, we used genetic tools to test the hypothesis that increased formation of superoxide (O2-*) radicals from a Rac1-regulated Nox2-containing NADPH oxidase is a key upstream mediator of ANG II-induced activation of serine-threonine kinase Akt, and that this signaling cascade plays a crucial role in ANG II-dependent cardiomyocyte hypertrophy. ANG II caused a significant time-dependent increase in Rac1 activation and O2-* production in primary neonatal rat cardiomyocytes, and these responses were abolished by adenoviral (Ad)-mediated expression of a dominant-negative Rac1 (AdN17Rac1) or cytoplasmic Cu/ZnSOD (AdCu/ZnSOD). Moreover, both AdN17Rac1 and AdCu/ZnSOD significantly attenuated ANG II-stimulated increases in cardiomyocyte size. Quantitative real-time PCR analysis demonstrated that Nox2 is the homolog expressed at highest levels in primary neonatal cardiomyocytes, and small interference RNA (siRNA) directed against it selectively decreased Nox2 expression by >95% and abolished both ANG II-induced O2-* generation and cardiomyocyte hypertrophy. Finally, ANG II caused a time-dependent increase in Akt activity via activation of AT(1) receptors, and this response was abolished by Ad-mediated expression of cytosolic human O2-* dismutase (AdCu/ZnSOD). Furthermore, pretreatment of cardiomyocytes with dominant-negative Akt (AdDNAkt) abolished ANG II-induced cellular hypertrophy. These findings suggest that O2-* generated by a Nox2-containing NADPH oxidase is a central mediator of ANG II-induced Akt activation and cardiomyocyte hypertrophy, and that dysregulation of this signaling cascade may play an important role in cardiac hypertrophy.

Adenoviridae↗
PubMed2006

Cloned ferrets produced by somatic cell nuclear transfer.

Somatic cell nuclear transfer (SCNT) offers great potential for developing better animal models of human disease. The domestic ferret (Mustela putorius furo) is an ideal animal model for influenza infections and potentially other human respiratory diseases such as cystic fibrosis, where mouse models have failed to reproduce the human disease phenotype. Here, we report the successful production of live cloned, reproductively competent, ferrets using species-specific SCNT methodologies. Critical to developing a successful SCNT protocol for the ferret was the finding that hormonal treatment, normally used for superovulation, adversely affected the developmental potential of recipient oocytes. The onset of Oct4 expression was delayed and incomplete in parthenogenetically activated oocytes collected from hormone-treated females relative to oocytes collected from females naturally mated with vasectomized males. Stimulation induced by mating and in vitro oocyte maturation produced the optimal oocyte recipient for SCNT. Although nuclear injection and cell fusion produced mid-term fetuses at equivalent rates (approximately 3-4%), only cell fusion gave rise to healthy surviving clones. Single cell fusion rates and the efficiency of SCNT were also enhanced by placing two somatic cells into the perivitelline space. These species-specific modifications facilitated the birth of live, healthy, and fertile cloned ferrets. The development of microsatellite genotyping for domestic ferrets confirmed that ferret clones were genetically derived from their respective somatic cells and unrelated to their surrogate mother. With this technology, it is now feasible to begin generating genetically defined ferrets for studying transmissible and inherited human lung diseases. Cloning of the domestic ferret may also aid in recovery and conservation of the endangered black-footed ferret and European mink.

Animals↗
PubMed2006

rAAV2 traffics through both the late and the recycling endosomes in a dose-dependent fashion.

Inefficient trafficking of recombinant adeno-associated virus type-2 (rAAV2) to the nucleus is a major barrier for transduction. Using imaging and subcellular fractionation techniques, we evaluated the extent of rAAV2 movement through the late (Rab7) and recycling (Rab11) endosomes. Following rAAV2 infection of HeLa cells, immunoisolation of HA-Rab7- or HA-Rab11-tagged endosomes and intracellular colocalization of Cy3-labeled rAAV2 with EGFP-Rab7 or EGFP-Rab11 markers demonstrated dose-dependent trafficking of rAAV2 through the recycling and late endosomal compartments. At low multiplicities of infection (m.o.i. 100 genomes/cell), rAAV2 predominantly trafficked to the Rab7 compartment. In contrast, rAAV2 predominantly trafficked to the recycling endosome at 100-fold higher m.o.i. siRNA studies inhibiting either Rab7 or Rab11 demonstrated that reducing Rab11 protein levels more significantly inhibited rAAV2 transduction on a per genome basis compared to inhibition of Rab7. Dose-response curves, comparing the m.o.i. of AV2Luc infection to relative transduction, also supported the hypothesis that viral movement through the Rab11 compartment at high m.o.i. is more competent for transgene expression ( approximately 100-fold) than virus that moves through the Rab7 compartment at low m.o.i. These findings suggest that strategies to shunt viral movement from the late to the recycling endosome may be effective at increasing viral transduction for gene therapy.

Biomarkers↗
PubMed2006

Stem cells in the lung.

The lung is composed of two major anatomically distinct regions-the conducting airways and gas-exchanging airspaces. From a cell biology standpoint, the conducting airways can be further divided into two major compartments, the tracheobronchial and bronchiolar airways, while the alveolar regions of the lung make up the gas-exchanging airspaces. Each of these regions consists of distinct epithelial cell types with unique cellular physiologies and stem cell compartments. This chapter focuses on model systems with which to study stem cells in the adult tracheobronchial airways, also referred to as the proximal airway of the lung. Important in such models is an appreciation for the diversity of stem cell niches in the conducting airways that provide localized environmental signals to both maintain and mobilize stem cells in the setting of airway injury and normal cellular turnover. Because cellular turnover in airways is relatively slow, methods for analysis of stem cells in vivo have required prior injury to the lung. In contrast, ex vivo and in vitro models for analysis of airway stem cells have used genetic markers to track lineage relationships together with reconstitution systems that mimic airway biology. Over the past decades, several widely acceptable methods have been developed and used in the characterization of adult airway stem/progenitor cells. These include localization of label-retaining cells (LRCs), retroviral tagging of epithelial cells seeded into xenografts, air-liquid interface cultures to track clonal proliferative potential, and multiple transgenic mouse models. This chapter reviews the biologic context and use of these models while providing detailed methods for several of the more broadly useful models for studying adult airway stem/progenitor cell types.

Adult Stem Cells↗
PubMed2006

Nox2 and Rac1 regulate H2O2-dependent recruitment of TRAF6 to endosomal interleukin-1 receptor complexes.

Reactive oxygen species (ROS) generated by NADPH oxidases (Nox) have been implicated in the regulation of signal transduction. However, the cellular mechanisms that link Nox activation with plasma membrane receptor signaling remain poorly defined. We have found that Nox2-derived ROS influence the formation of an active interleukin-1 (IL-1) receptor complex in the endosomal compartment by directing the H2O2-dependent binding of TRAF6 to the IL-1R1/MyD88 complex. Clearance of both superoxide and H2O2 from within the endosomal compartment significantly abrogated IL-1beta-dependent IKK and NF-kappaB activation. MyD88-dependent endocytosis of IL-1R1 following IL-1beta binding was required for the redox-dependent formation of an active endosomal receptor complex competent for IKK and NF-kappaB activation. Small interfering RNAs to either MyD88 or Rac1 inhibited IL-1beta induction of endosomal superoxide and NF-kappaB activation. However, MyD88 and Rac1 appear to be recruited independently to IL-1R1 following ligand stimulation. In this context, MyD88 binding was required for inducing endocytosis of IL-1R1 following ligand binding, while Rac1 facilitated the recruitment of Nox2 into the endosomal compartment and subsequent redox-dependent recruitment of TRAF6 to the MyD88/IL-1R1 complex. The identification of Nox-active endosomes helps explain how subcellular compartmentalization of redox signals can be used to direct receptor activation from the plasma membrane.

Adaptor Proteins, Signal Transducing↗
PubMed2005

Factors affecting the efficiency of embryo transfer in the domestic ferret (Mustela putorius furo).

Embryo transfer (ET) to recipient females is a foundational strategy for a number of assisted reproductive technologies, including cloning by somatic cell nuclear transfer. In an attempt to develop efficient ET in domestic ferrets, factors affecting development of transferred embryo were investigated. Unilateral and bilateral transfer of zygotes or blastocysts in the oviduct or uterus was evaluated in recipient nulliparous or primiparous females. Developing fetuses were collected from recipient animals 21 days post-copulation and examined. The percentage of fetal formation was different (P<0.05) for unilateral and bilateral transfer of zygotes (71%) in nulliparous females with bilateral transfer (56%) in primiparous recipients. The percentage (90%) of fetal formation in nulliparous recipients following unilateral transfer of blastocysts was higher (P<0.05) than that observed in primiparous recipients with bilateral ET (73%). Notably, the percentage of fetal formation was higher (P<0.05) when blastocyts were transferred as compared to zygotes (90% versus 71%). Transuterine migration of embryos occurred following all unilateral transfers and also in approximately 50% of bilateral transfers with different number of embryos in each uterine horn. These data will help to facilitate the development of assisted reproductive strategies in the ferret and could lead to the use of this species for modeling human disease and for conservation of the endangered Mustelidae species such as black-footed ferret and European mink.

Animals↗
PubMed2005

Nuclear transfer of M-phase ferret fibroblasts synchronized with the microtubule inhibitor demecolcine.

The development of reconstructed embryos following nuclear transfer (NT) appears to be dependent upon a variety of factors, including cell cycle synchronization between the donor nucleus and recipient oocyte. Here we use the microtubule inhibitor, demecolcine, to synchronize ferret fibroblasts in metaphase (M-phase) in order to match their cell cycle position with that of the recipient oocyte at the time of NT. The fibroblasts were obtained from 28-day fetuses and cultured for 1-30 days prior to NT. Fibroblast cultures were treated with 0.05 microg/ml of demecolcine for 3 hr or overnight (14-16 hr) after various times in culture to determine the optimal conditions for M-phase synchronization. The percentage of G2/M-phase cells in demecolcine-treated cultures was significantly greater than that found in untreated cultures (P<0.05). Optimally synchronized M-phase fibroblasts were collected by mitotic shake-off and evaluated for their effectiveness in NT. M-phase somatic cell-derived NT embryos reconstituted by electrofusion or microinjection underwent implantation and formed fetuses at similar rates (5.4% vs. 3.4%, and 1.8% vs. 1.2%, respectively); however, no NT embryos developed to term. In summary, these data demonstrate two important points. First, demecolcine treatment effectively synchronizes ferret fibroblasts in M-phase of the cell cycle; and second, these somatic cells are capable of driving embryo development following NT. Our results should facilitate the development of cloned ferrets as an animal model for human lung disease such as influenza and cystic fibrosis.

Analysis of Variance↗
PubMed2005

Interleukin-1beta induction of NFkappaB is partially regulated by H2O2-mediated activation of NFkappaB-inducing kinase.

Reactive oxygen species (ROS) have been demonstrated to act as second messengers in a number of signal transduction pathways, including NFkappaB. However, the mechanism(s) by which ROS regulate NFkappaB remain unclear and controversial. In the present report, we describe a mechanism whereby interleukin-1beta (IL-1beta) stimulation of NFkappaB is partially regulated by H2O2-mediated activation of NIK and subsequent NIK-mediated phosphorylation of IKKalpha. IL-1beta induced H2O2 production in MCF-7 cells and clearance of this ROS through the expression of GPx-1 reduced NFkappaB transcriptional activation by inhibiting NIK-mediated phosphorylation of IKKalpha. Although IKKalpha and IKKbeta were both involved in IL-1beta-mediated activation of NFkappaB, only the IKKalpha-dependent component was modulated by changes in H2O2 levels. Interestingly, in vitro reconstitution experiments demonstrated that NIK was activated by a very narrow range of H2O2 (1-10 microM), whereas higher concentrations (100 microM to 1 mM) inhibited NIK activity. Treatment of cells with the general Ser/Thr phosphatase inhibitor (okadaic acid) lead to activation of NFkappaB and enhanced NIK activity as a IKKalpha kinase, suggesting that ROS may directly regulate NIK through the inhibition of phosphatases. Recruitment of NIK to TRAF6 following IL-1beta stimulation was inhibited by H2O2 clearance and Rac1 siRNA, suggesting that Rac-dependent NADPH oxidase may be a source of ROS required for NIK activation. In summary, our studies have demonstrated that redox regulation of NIK by H2O2 is mechanistically important in IL-1beta induction of NFkappaB activation.

Breast Neoplasms↗
PubMed2005

Efficient in vivo gene expression by trans-splicing adeno-associated viral vectors.

Although adeno-associated virus (AAV)-mediated gene therapy has been hindered by the small viral packaging capacity of the vector, trans-splicing AAV vectors are able to package twice the size of the vector genome. Unfortunately, the efficiency of current trans-splicing vectors is very low. Here we show that rational design of the gene splitting site has a profound influence on trans-splicing vector-mediated gene expression. Using mRNA accumulation as a guide, we generated a set of efficient trans-splicing vectors and achieved widespread expression of the 6-kb DeltaH2-R19 mini-dystrophin gene in skeletal muscle of mdx mice, a model for Duchenne muscular dystrophy. The dystrophic phenotype was ameliorated in both adult and aged mice. This demonstrates the use of trans-splicing vectors to efficiently express a large therapeutic structural protein. This strategy should be applicable to other large therapeutic genes or large transcription regulatory elements.

Animals↗
PubMed2005

Species-specific differences in mouse and human airway epithelial biology of recombinant adeno-associated virus transduction.

Differences in airway epithelial biology between mice and humans have presented challenges to evaluating gene therapies for cystic fibrosis (CF) using murine models. In this context, recombinant adeno-associated virus (rAAV) type 2 and rAAV5 vectors have very different transduction efficiencies in human air-liquid interface (ALI) airway epithelia (rAAV2 approximately = rAAV5) as compared with mouse lung (rAAV5 >> rAAV2). It is unclear if these differences are due to species-specific airway biology or limitations of ALI cultures to reproduce in vivo airway biology. To this end, we compared rAAV2 and rAAV5 transduction biology in mouse and human ALI cultures, and investigated the utility of murine deltaF508 cystic fibrosis transmembrane conductance regulator (CFTR) ALI epithelia to study CFTR complementation. Our results demonstrate that mouse ALI epithelia retain in vivo preferences for rAAV serotype transduction from the apical membrane (rAAV5 >> rAAV2) not seen in human epithelia (rAAV2 approximately = rAAV5). Viral binding of rAAV2 and rAAV5 to the apical surface of mouse ALI airway epithelia was not significantly different, and proteasome-modulating agents significantly enhanced rAAV2 transduction to a level equivalent to that of rAAV5 in the presence of these agents, suggesting that the ubiquitin/proteasome pathway represents a more significant intracellular block for rAAV2 transduction of mouse airway epithelia. Interestingly, cAMP-inducible chloride currents were enhanced in deltaF508CFTR mouse ALI cultures, making this model incompatible with CFTR complementation studies. These studies emphasize species-specific differences in airway biology between mice and humans that significantly influence the use of mice as surrogate models for rAAV transduction and gene therapy for CF.

Animals↗
PubMed2005

Lysozyme secretion by submucosal glands protects the airway from bacterial infection.

Submucosal glands are abundant (approximately 1 gland/mm2) secretory structures in the tracheobronchial airways of the human lung. Because submucosal glands express antibacterial proteins, it has been proposed that they contribute to lung defense. However, this concept is challenged by the fact that mice do not have submucosal glands in their bronchial airways, yet are quite resistant to bacterial lung infection. The contribution of airway submucosal glands to host defense is also debated as a pathophysiologic component of cystic fibrosis lung disease. Here, we asked whether submucosal glands protect airways against bacterial infection. By comparing tracheal xenograft airways with and without glands, we found that the presence of glands enhanced bacterial killing in vivo and by airway secretions in vitro. Moreover, immunodepletion studies suggested that lysozyme is a major antibacterial component secreted by submucosal glands. These studies provide evidence that submucosal glands are a major source of antibacterials critical for maintaining sterile airways.

Animals↗