Cellular Reprogramming Allows Generation of Autologous Hematopoietic Progenitors From AML Patients That Are Devoid of Patient-Specific Genomic Aberrations

Current treatments that use hematopoietic progenitor cell (HPC) transplantation in acute myeloid leukemia (AML) patients substantially reduce the risk of relapse, but are limited by the availability of immune compatible healthy HPCs. Although cellular reprogramming has the potential to provide a novel autologous source of HPCs for transplantation, the applicability of this technology toward the derivation of healthy autologous hematopoietic cells devoid of patient-specific leukemic aberrations from AML patients must first be evaluated. Here, we report the generation of human AML patient-specific hematopoietic progenitors that are capable of normal in vitro differentiation to myeloid lineages and are devoid of leukemia-associated aberration found in matched patient bone marrow. Skin fibroblasts were obtained from AML patients whose leukemic cells possessed a distinct, leukemia-associated aberration, and used to create AML patient-specific induced pluripotent stem cells (iPSCs). Through hematopoietic differentiation of AML patient iPSCs, coupled with cytogenetic interrogation, we reveal that AML patient-specific HPCs possess normal progenitor capacity and are devoid of leukemia-associated mutations. Importantly, in rare patient skin samples that give rise to mosaic fibroblast cultures that continue to carry leukemia-associated mutations; healthy hematopoietic progenitors can also be generated via reprogramming selection. Our findings provide the proof of principle that cellular reprogramming can be applied on a personalized basis to generate healthy HPCs from AML patients, and should further motivate advances toward creating transplantable hematopoietic stem cells for autologous AML therapy. Stem Cells2013;33:1839–1849

Innate immune response of human pluripotent stem cell-derived airway epithelium

The acquisition of innate immune response is requisite to having bona fide differentiation of airway epithelium. Procedures developed to differentiate lung airway from human pluripotent stem cells (hPSCs) have demonstrated anecdotal evidence for innate immune response, but an in-depth exploration of response levels is lacking. Herein, using an established method of airway epithelial generation from hPSCs, we show that hPSC-derived epithelial cells are able to up-regulate expression of TNFα, IL8 and IL1β in response to challenge with bacterial endotoxin LPS, but lack response from genes associated with innate immune response in other cell types. Further, stimulation of cells with TNF-α resulted in auto-induction of TNFα transcript, as well as cytokine responses of IL8 and IL1β. The demonstration of innate immune induction in hPSC-derived airway epithelia gives further strength to the functionality of in vitro protocols aimed at generating differentiated airway cells that can potentially be used in a translational setting. Finally, we propose that innate immune challenge of airway epithelium from human pluripotent stem cell sources be used as a robust validation of functional in vitro differentiation.

Pleiotropic roles of Notch signaling in normal, malignant, and developmental hematopoiesis in the human

The Notch signaling pathway is evolutionarily conserved across species and plays an important role in regulating cell differentiation, proliferation, and survival. It has been implicated in several different hematopoietic processes including early hematopoietic development as well as adult hematological malignancies in humans. This review focuses on recent developments in understanding the role of Notch signaling in the human hematopoietic system with an emphasis on hematopoietic initiation from human pluripotent stem cells and regulation within the bone marrow. Based on recent insights, we summarize potential strategies for treatment of human hematological malignancies toward the concept of targeting Notch signaling for fate regulation.

T cell unresponsiveness in a pediatric cystic fibrosis patient: a case report

A girl was diagnosed with cystic fibrosis (CF) at birth, with repeatedly positive sweat tests and homozygous F508del mutations of her CF transmembrane conductance regulator (CFTR) gene. From an early age, her lung disease was more severe than her birth cohort peers despite aggressive treatment. At the age of 16 she was listed for lung transplantation, but prior to transplant was not on systemic corticosteroids or other immunosuppressive agents. In response to ex vivo stimulation, her pre-transplant peripheral blood T cells unexpectedly failed to produce detectable levels of IFN-γ, unlike cells from healthy controls or from another girl with CF and lung disease of comparable severity. Furthermore, naïve T cells freshly isolated from her peripheral blood showed a complete block of T cell differentiation into Th1, Th17 and Treg lineages, even in the presence of cytokines known to promote differentiation into the respective lineages. Her serology has been remarkably devoid of evidence of exposure to viruses that have been associated with T cell exhaustion. However, her freshly isolated naïve T cells showed sustained expression of markers of T cell exhaustion, which were further induced upon ex vivo stimulation, pointing to T cell exhaustion as the cause of the failure of naïve T cells to undergo differentiation in response to cytokine stimulation. Although excessive inflammation in CF lung can be both ineffective at clearing certain pathogens as well as destructive to the lung tissue itself, adequate inflammation is a component of an effective overall immune response to microbial pathogens. Our present findings suggest that intrinsic impairment of T cell differentiation may have contributed to the greater severity and more rapid progression of her CF lung disease than of the lung disease of most of her peers.

Intrinsic predisposition of naïve cystic fibrosis T cells to differentiate towards a Th17 phenotype

Background

Cystic fibrosis (CF) is a complex, multi-system, life-shortening, autosomal recessive disease most common among Caucasians. Pulmonary pathology, the major cause of morbidity and mortality in CF, is characterized by dysregulation of cytokines and a vicious cycle of infection and inflammation. This cycle causes a progressive decline in lung function, eventually resulting in respiratory failure and death. The Th17 immune response plays an active role in the pathogenesis of CF pulmonary pathology, but it is not known whether the pathophysiology of CF disease contributes to a heightened Th17 response or whether CF naïve CD4+ T lymphocytes (Th0 cells) intrinsically have a heightened predisposition to Th17 differentiation.

Methods

To address this question, Th0 cells were isolated from the peripheral blood of CF mice, human CF subjects and corresponding controls. Murine Th0 cells were isolated from single spleen cell suspensions using fluorescence-activated cell sorting. Lymphocytes from human buffy coats were isolated by gradient centrifugation and Th0 cells were further isolated using a human naïve T cell isolation kit. Th0 cells were then assessed for their capacity to differentiate along Th17, Th1 or Treg lineages in response to corresponding cytokine stimulation. The T cell responses of human peripheral blood cells were also assessed ex vivo using flow cytometry.

Results

Here we identify in both mouse and human CF an intrinsically enhanced predisposition of Th0 cells to differentiate towards a Th17 phenotype, while having a normal propensity for differentiation into Th1 and Treg lineages. Furthermore, we identify an active Th17 response in the peripheral blood of human CF subjects.

Conclusions

We propose that these novel observations offer an explanation, at least in part, for the known increased Th17-associated inflammation of CF and the early signs of inflammation in CF lungs before any evidence of infection. Moreover, these findings point towards direct modulation of T cell responses as a novel potential therapeutic strategy for combating excessive inflammation in CF.

Analysis of pulmonary dendritic cell maturation and migration during allergic airway inflammation

Dendritic cells (DCs) are the key players involved in initiation of adaptive immune response by activating antigen-specific T cells. DCs are present in peripheral tissues in steady state; however in response to antigen stimulation, DCs take up the antigen and rapidly migrate to the draining lymph nodes where they initiate T cell response against the antigen. Additionally, DCs also play a key role in initiating autoimmune as well as allergic immune response. DCs play an essential role in both initiation of immune response and induction of tolerance in the setting of lung environment. Lung environment is largely tolerogenic, owing to the exposure to vast array of environmental antigens. However, in some individuals there is a break in tolerance, which leads to induction of allergy and asthma. In this study, we describe a strategy, which can be used to monitor airway DC maturation and migration in response to the antigen used for sensitization. The measurement of airway DC maturation and migration allows for assessment of the kinetics of immune response during airway allergic inflammation and also assists in understanding the magnitude of the subsequent immune response along with the underlying mechanisms. Our strategy is based on the use of ovalbumin as a sensitizing agent. Ovalbumin-induced allergic asthma is a widely used model to reproduce the airway eosinophilia, pulmonary inflammation and elevated IgE levels found during asthma. After sensitization, mice are challenged by intranasal delivery of FITC labeled ovalbumin, which allows for specific labeling of airway DCs which uptake ovalbumin. Next, using several DC specific markers, we can assess the maturation of these DCs and can also assess their migration to the draining lymph nodes by employing flow cytometry.

Elf3 regulates allergic airway inflammation by controlling dendritic cell-driven T cell differentiation

Elf3 belongs to the Ets family of transcription factors and has been implicated in inflammation. Elf3 is highly expressed in the lungs, and Elf3(-/-) mice are impaired in IL-6 production after intranasal LPS exposure. To identify the role of Elf3 in Th17-driven pulmonary inflammation, we have performed epicutaneous sensitization of Elf3(-/-) mice with OVA followed by airway OVA challenge and have identified Elf3(-/-) mice to be impaired in induction of Th17 response, attributable to impairment of IL-6 production by dendritic cells (DCs). However, increased serum levels of OVA-specific IgG1 and IgE were observed, pointing toward an exaggerated Th2 response. To study Th2 response, we performed i.p. sensitization of Elf3(-/-) mice with OVA and confirmed loss of Elf3 to result in an aggravated Th2 response, characterized by increased generation of IL-4-producing T cells, increased levels of OVA-specific IgE and IgG1 Ab titers, and increased serum levels of Th2 cytokines, together with extensive inflammation and mucus production in airways. Elf3(-/-) DCs were impaired in priming Th1 differentiation, which, in turn, promoted Th2 differentiation. This was mediated by the ability of Elf3(-/-) DCs to undergo hypermaturation but secrete significantly lower levels of IL-12 in response to inflammatory stimuli. The impairment of IL-12 production was due to impairment of IL-12p40 gene induction in Elf3(-/-) DCs in response to inflammatory stimuli. Taken together, our study identifies a novel function of Elf3 in regulating allergic airway inflammation by regulating DC-driven Th1, Th2, and Th17 differentiation.

Complexity of dendritic cell subsets and their function in the host immune system

Dendritic cells (DCs) are professional antigen-presenting cells that are critical for induction of adaptive immunity and tolerance. Traditionally DCs have been divided into two discrete subtypes, which comprise conventional and non-conventional DCs. They are distributed across various organs in the body and comprise a heterogeneous population, which has been shown to display differences in terms of surface marker expression, function and origins. Recent studies have shed new light on the process of DC differentiation and distribution of DC subtypes in various organs. Although monocytes, macrophages and DCs share a common macrophage-DC progenitor, a common DC progenitor population has been identified that exclusively gives rise to DCs and not monocytes or macrophages. In this review, we discuss the recent advances in our understanding of DC differentiation and subtypes and provide a comprehensive overview of various DC subtypes with emphasis on their function and origins. Furthermore, in light of recent developments in the field of DC biology, we classify DCs based on the precursor populations from which the various DC subsets originate. We classify DCs derived from common DC progenitor and pre-DC populations as conventional DCs, which includes both migratory and lymphoid-resident DC subsets and classify monocyte-derived DCs and plasmacytoid DCs as non-conventional DCs.

Role of dendritic cells in the induction of regulatory T cells

Dendritic cells (DCs) play a key role in initiating immune responses and maintaining immune tolerance. In addition to playing a role in thymic selection, DCs play an active role in tolerance under steady state conditions through several mechanisms which are dependent on IL-10, TGF-β, retinoic acid, indoleamine-2,3,-dioxygenase along with vitamin D. Several of these mechanisms are employed by DCs in induction of regulatory T cells which are comprised of Tr1 regulatory T cells, natural and inducible foxp3⁺ regulatory T cells, Th3 regulatory T cells and double negative regulatory T cells. It appears that certain DC subsets are highly specialized in inducing regulatory T cell differentiation and in some tissues the local microenvironment plays a role in driving DCs towards a tolerogenic response. In this review we discuss the recent advances in our understanding of the mechanisms underlying DC driven regulatory T cell induction.

Elf3 plays a role in regulating dendritic cell maturation and function (100.42)

Elf3 belongs to the family of epithelium-specific Ets transcription factors and can be upregulated in non-epithelial cells upon cytokine stimulation. Among Ets family transcription factors, Elf3 is most highly induced during inflammation, yet its function is not well understood. Here we demonstrate an important role of Elf3 in regulating dendritic cell (DC) function. Intraperitoneal injection of ovalbumin (OVA)-Alum to Elf3-/- mice resulted in increased migration of DCs to the peritoneal space along with hypermaturation followed by increase in subsequent migration of DCs to the draining lymph nodes. In vitro cultured Elf3-/- DCs underwent spontaneous maturation in absence of any inflammatory stimuli and upon exposure to inflammatory stimuli underwent hypermaturation compared to Elf3+/+ DCs, indicating a role of Elf3 in regulation DC maturation. Elf3-/- mice had normal T cell development but mounted an exaggerated Th2 response upon OVA exposure. Naïve T cells cultured with Elf3-/- DCs showed impairment in Th1 and Th17 differentiation with an increased propensity for Th2 differentiation. This was mediated by an impairment of IL-6 and IL-12 production by Elf3-/- DCs. The impairment of IL-6 and IL-12 production was due to impairment of IL-6 and IL-12p40 gene induction in Elf3-/- DCs in response to inflammatory stimuli. Impairment of Th1 differentiation promoted Th2 differentiation. Taken together, our findings identify a role of Elf3 in regulating DC maturation and function.

Dendritic cell apoptosis: regulation of tolerance versus immunity

Dendritic cell (DC) apoptosis is an important event that regulates the balance between tolerance and immunity through multiple pathways, and defects in DC apoptosis can trigger autoimmunity. DC apoptosis is also associated with immunosuppression and has been observed under several pathologies and infections. Recent studies indicate that apoptotic DCs can also play an active role in induction of tolerance. This review discusses the regulatory pathways of DC apoptosis, stimuli inducing DC apoptosis, and the implications of DC apoptosis in the induction of immunosuppression and/or tolerance.

Uptake of apoptotic DC converts immature DC into tolerogenic DC that induce differentiation of Foxp3+ Treg

DC apoptosis has been observed in patients with cancer and sepsis, and defects in DC apoptosis have been implicated in the development of autoimmune diseases. However, the mechanisms of how DC apoptosis affects immune responses, are unclear. In this study, we showed that immature viable DC have the ability to uptake apoptotic DC as well as necrotic DC without it being recognized as an inflammatory event by immature viable DC. However, the specific uptake of apoptotic DC converted immature viable DC into tolerogenic DC, which were resistant to LPS-induced maturation. These tolerogenic DC secreted increased levels of TGF-beta1, which induced differentiation of naïve T cells into Foxp3(+) Treg. Furthermore, induction of Treg differentiation only occurred upon uptake of apoptotic DC and not apoptotic splenocytes by viable DC, indicating that it is specifically the uptake of apoptotic DC that gives viable immature DC the potential to induce Foxp3(+) Treg. Taken together, these findings identify uptake of apoptotic DC by viable immature DC as an immunologically tolerogenic event.

Elf3 regulates dendritic cell driven T cell differentiation (99.1)

Elf3 belongs to the family of epithelium specific Ets transcription factors and can be upregulated in non-epithelial cells upon cytokine stimulation. Elf3-/- mice have normal T cell development and T cell differentiation into different T helper lineages. Here we show that upon epicutaneous sensitization with ovalbumin(OVA) followed by OVA intranasal challenge, Elf3-/- mice display a defect in Th17 induction, though OVA specific IgE and IgG1 antibody titers are several folds higher and airway inflammation is more extensive compared to Elf3+/+ mice, indicating an exaggerated Th2 response. Furthermore, intraperitoneal sensitization of Elf3-/- mice with OVA followed by OVA intranasal challenge, confirmed that Elf3-/- mice mounted an exaggerated Th2 response. Since, dendritic cells (DCs) are key players in initiation of adaptive immune response, we analyzed DC migration upon OVA challenge and showed that pulmonary DCs underwent hyperactivation in Elf3-/- mice compared to Elf3+/+ mice and rates of DC migration to the airway draining lymph nodes were also significantly higher in Elf3-/- mice, indicating that DCs may mediate the exaggerated Th2 response observed in Elf3-/- mice. Further analysis revealed that Elf3-/- DCs are more prone to maturation than Elf3+/+ DCs and upon maturation, Elf3-/- DCs preferentially secrete chemokines/cytokines that are important in polarizing Th2 differentiation. Taken together, these findings reveal a role of Elf3 in DC driven T cell differentiation.

An improved method of measurement of ECG parameters for online medical diagnosis

The accuracy in the online measurement of ECG parameters has a decisive role in the better diagnosis and effective treatment of the diseases. The present paper describes a Lab-VIEW based programming using Pan Tompkins method to extract out QRS complex whereas QT interval measurements were carried out using Mat-lab based math-script module. Hilbert transform has been applied on the ECG signal to convert it into an analytical signal for better peak detection. Peak detection and other parameters like RR interval, HR and several time domain measures of heart rate variability such as RR mean and standard deviations, HR mean and standard deviations, RMSSSD, NN50 count, pNN50 etc were calculated for several other clinical applications apart from online disease diagnosis.

Apoptotic dendritic cells induce tolerance in mice through suppression of dendritic cell maturation and induction of antigen-specific regulatory T cells

Dendritic cell (DC) apoptosis has been shown to play a role in maintaining a balance between tolerance and immunity. However, the mechanisms of how DC apoptosis affects the immune response are unclear. We have shown that in vitro culture of apoptotic DCs with immature DCs, results in their uptake by immature DCs, which subsequently turn into tolerogenic DCs, which then secrete TGF-beta1 and induce Foxp3(+) regulatory T cells (T(regs)). In this study we looked at the effects of apoptotic DCs in vivo. Here we show that apoptotic DCs are taken up by viable DCs in vivo, which suppresses the ability of viable DCs to undergo maturation and subsequent migration to the lymph nodes in response to LPS. Additionally, delivery of apoptotic DCs to LPS inflamed lungs results in resolution of inflammation, which is mediated by the ability of apoptotic DCs to suppress response of viable DCs to LPS. Additionally, apoptotic DCs also induce TGF-beta1 secretion in the mediastinal lymph nodes, which results in expansion of Foxp3(+) T(regs). Most importantly, we show that delivery of apoptotic DCs followed by OVA in CFA to mice suppresses T cell response to OVA and instead induces de novo generation of OVA-specific T(regs). Furthermore, delivery of apoptotic DCs followed by OVA in CFA results in expansion of T(regs) in TCR transgenic (OT-II) mice. These findings demonstrate that apoptotic DCs are taken up by viable DCs in vivo, which promotes tolerance through suppression of DC maturation and induction of T(regs).

Gender differences in pulmonary regenerative response to naphthalene-induced bronchiolar epithelial cell injury

OBJECTIVES

Accumulating evidence suggests that gender affects the incidence and severity of several pulmonary diseases. Previous studies on mice have shown gender differences in susceptibility to naphthalene-induced lung injury, where Clara cell damage was found to occur earlier and to be more extensive in females than in males. However, very little is known about whether there are any gender differences in subsequent lung repair responses. The aim of this study was to investigate whether gender plays an important role in pulmonary regenerative response to naphthalene-induced Clara cell ablation.

MATERIALS AND METHODS

Adult male and female mice were injected with a low, medium, or high dose of naphthalene, and lung tissue regeneration was examined by immunohistochemical staining for cell proliferation marker (Ki-67) and mitosis marker (phosphohistone-3).

RESULTS

Histopathological analysis showed that naphthalene-induced Clara cell necrosis was more prominent in the lungs of female mice as compared to male mice. Cell proliferation and mitosis in both the distal bronchiolar airway epithelium and peribronchiolar interstitium of female mice was significantly greater than that of male mice after treatment with the low and medium doses. However, after treatment with high dose of naphthalene, lung regeneration was delayed in female mice, while male mice mounted a timely regenerative response.

CONCLUSIONS

These findings show that there are clear gender differences in naphthalene-induced lung injury and repair.

Uptake of apoptotic dendritic cells by viable dendritic cells: a novel mechanism of inducing immune tolerance (48.7)

Dendritic cells (DCs) are professional antigen-presenting cells, which can be affected by the death of other cells in close proximity. Spontaneous DC apoptosis has been observed in patients with sepsis and breast cancer. Additionally defects in DC apoptosis have also been associated with development of autoimmune diseases. However, the mechanisms of how DC apoptosis affects immune responses are unclear. Here we show that apoptotic DCs can mediate induction of immune tolerance by converting immature DCs into tolerogenic DCs. The uptake of apoptotic DCs by viable DCs prevents LPS-induced activation and T-cell proliferation, and also results in the upregulation of TGF-beta2 gene expression and TGF-beta1 secretion, which mediates differentiation of naïve T cells into regulatory T cells (Tregs). Additionally, delivery of apoptotic DCs prevents LPS-induced DC maturation and migration to lymph nodes in mice. Moreover, intranasal delivery of apoptotic DCs to LPS-inflamed lungs results in rapid resolution of inflammation along with production of TGF-beta1 and expansion of Tregs. Delivery of apoptotic DCs followed by immunization with ovalbumin (OVA) in Complete Freund's Adjuvant (CFA) resulted in generation of OVA-specific Tregs in wild-type mice and expansion of Tregs in T-cell receptor transgenic (OT-II) mice. Taken together, our findings identify apoptotic DCs as potent inducers of immunological tolerance.

ATP plays a role as a danger signal that activates macrophages during adenoviral infection (133.38)

We have previously shown that adenovirus infection of epithelial cells and macrophages co-culture resulted in synergistic induction of pro-inflammatory mediators such as cytokines, nitric oxide (NO), and reactive oxygen species (ROS) and caused cytotoxic responses. Here, we investigated whether ATP plays a role during the inflammatory response against adenovirus using the co-culture system. We found that pre-treatment of the co-culture with oxidized-ATP inhibited induction of NO and ROS and reduced cytotoxicity during adenoviral infection. Furthermore, we demonstrated that ATP signalling through P2X7 receptor is required in generation of NO and ROS using P2X7 deficient macrophage cell line. These results indicate that ATP plays a role as a danger signal to regulate macrophage activation during inflammatory response against adenoviral infection.

Characterization of pulmonary T cell response to helper-dependent adenoviral vectors following intranasal delivery

In spite of the extensive research in the field of gene therapy, host immune responses continue to be the major barrier in translating basic research to clinical practice. Helper-dependent adenoviral (HD-Ad) vectors show great potential for pulmonary gene therapy, but the knowledge of pulmonary immune responses toward these vectors is very limited. In this study, we show that HD-Ad vectors are potent stimulators of dendritic cell (DC) maturation, thus leading to stimulation of T cell proliferation with approximately 6% of naive CD4(+) T cells from pulmonary mediastinal lymph node responding to HD-Ad-treated DCs. In contrast to the belief that HD-Ad vectors are unable to prime adaptive immune response, we show for the first time, through in vivo pulmonary studies in mice, that HD-Ad vectors can prime CD4(+) and CD8(+) T cell responses in the lung at high and substantially low doses. This indicates cross-presentation of HD-Ad-derived epitopes by DCs to prime CD8(+) T cell responses. To assess the basis of pulmonary T cell response against HD-Ad vectors, we examined the response of conventional DCs (cDCs) and plasmacytoid DCs (pDCs) in the lung. In response to HD-Ad delivery, there is induction of maturation in both cDC and pDC subsets, but it is the cDCs, not pDCs, that migrate rapidly to draining lymph nodes within the first 2 days after vector delivery to prime adaptive immune response against these vectors. These findings have implications for development of strategies to prevent adaptive immune responses against gene therapy vectors.

Nacystelyn enhances adenoviral vector-mediated gene delivery to mouse airways

Adenoviral vector-mediated gene delivery has been vastly investigated for cystic fibrosis (CF) gene therapy; however, one of its drawbacks is the low efficiency of gene transfer, which is due to basolateral colocalization of viral receptors, immune responses to viral vectors and the presence of a thick mucus layer in the airways of CF patients. Therefore, enhancement of gene transfer can lead to reduction in the viral dosage, which could further reduce the acute toxicity associated with the use of adenoviral vectors. Nacystelyn (NAL) is a mucolytic agent with anti-inflammatory and antioxidant properties, and has been used clinically in CF patients to reduce mucus viscosity in the airways. In this study, we show that pretreatment of the airways with NAL followed by administration of adenoviral vectors in complex with DEAE-Dextran can significantly enhance gene delivery to the airways of mice without any harmful effects. Moreover, NAL pretreatment can reduce the airway inflammation, which is normally observed after delivery of adenoviral particles. Taken together, these results indicate that NAL pretreatment followed by adenoviral vector-mediated gene delivery can be beneficial to CF patients by increasing the efficiency of gene transfer to the airways, and reducing the acute toxicity associated with the administration of adenoviral vectors.

Potential of helper-dependent adenoviral vectors in modulating airway innate immunity

Innate immune responses form the first line of defense against foreign insults and recently significant advances have been made in our understanding of the initiation of innate immune response along with its ability to modulate inflammation. In airway diseases such as asthma, COPD and cystic fibrosis, over reacting of the airway innate immune responses leads to cytokine imbalance and airway remodeling or damage. Helper-dependent adenoviral vectors have the potential to deliver genes to modulate airway innate immune responses and have many advantages over its predecessors. However, there still are a few limitations that need to be addressed prior to their use in clinical applications.