Enhanced Lyn Activity Causes Severe, Progressive Emphysema and Lung Cancer

The epidemiological patterns of incident chronic obstructive pulmonary disease (COPD) and lung adenocarcinoma are changing, with an increasing fraction of disease occurring in patients who are never-smokers or were not exposed to traditional risk factors. However, causative mechanism(s) are obscure. Overactivity of Src family kinases (SFKs) and myeloid cell-dependent inflammatory lung epithelial and endothelial damage are independent candidate mechanisms, but their pathogenic convergence has not been demonstrated. Here we present a novel preclinical model in which an activating mutation in Lyn, a nonreceptor SFK that is expressed in immune cells, epithelium, and endothelium-all strongly implicated in the pathogenesis of COPD-causes spontaneous inflammation, early-onset progressive emphysema, and lung adenocarcinoma. Surprisingly, even though activated macrophages, elastolytic enzymes, and proinflammatory cytokines were prominent, bone marrow chimeras formally demonstrated that myeloid cells were not disease initiators. Rather, lung disease arose from aberrant epithelial cell proliferation and differentiation, microvascular lesions within an activated endothelial microcirculation, and amplified EGFR (epidermal growth factor receptor) expression. In human bioinformatics analyses, LYN expression was increased in patients with COPD and was correlated with increased EGFR expression, a known lung oncogenic pathway, and LYN was linked to COPD. Our study shows that a singular molecular defect causes a spontaneous COPD-like immunopathology and lung adenocarcinoma. Furthermore, we identify Lyn and, by implication, its associated signaling pathways as new therapeutic targets for COPD and cancer. Moreover, our work may inform the development of molecular risk screening and intervention methods for disease susceptibility, progression, and prevention of these increasingly prevalent conditions.

Progress in the development of kinase inhibitors for treating asthma and COPD

Current therapies to mitigate inflammatory responses involved in airway remodeling and associated pathological features of asthma and chronic obstructive pulmonary disease (COPD) are limited and largely ineffective. Inflammation and the release of cytokines and growth factors activate kinase signaling pathways that mediate changes in airway mesenchymal cells such as airway smooth muscle cells and lung fibroblasts. Proliferative and secretory changes in mesenchymal cells exacerbate the inflammatory response and promote airway remodeling, which is often characterized by increased airway smooth muscle mass, airway hyperreactivity, increased mucus secretion, and lung fibrosis. Thus, inhibition of relevant kinases has been viewed as a potential therapeutic approach to mitigate the debilitating and, thus far, irreversible airway remodeling that occurs in asthma and COPD. Despite FDA approval of several kinase inhibitors for the treatment of proliferative disorders, such as cancer and inflammation associated with rheumatoid arthritis and ulcerative colitis, none of these drugs have been approved to treat asthma or COPD. This review will provide a brief overview of the role kinases play in the pathology of asthma and COPD and an update on the status of kinase inhibitors currently in clinical trials for the treatment of obstructive pulmonary disease. In addition, potential issues associated with the current kinase inhibitors, which have limited their success as therapeutic agents in treating asthma or COPD, and alternative approaches to target kinase functions will be discussed.

Early-onset pulmonary and cutaneous vasculitis driven by constitutively active SRC-family kinase HCK

BACKGROUND

Inborn errors of immunity (IEI) are genetic disorders characterized by various degrees of immune dysregulation that can manifest as immune deficiency, autoimmunity or autoinflammation. The routine use of next-generation sequencing in the clinic has facilitated the identification of an ever-increasing number of IEI, revealing the roles of immunologically important genes in human pathologies. However, despite this progress, treatment is still extremely challenging.

OBJECTIVE

We report a new monogenic autoinflammatory disorder caused by a de novo activating mutation, p.Tyr515*, in hematopoietic cell kinase (HCK). The disease is characterized by cutaneous vasculitis and chronic pulmonary inflammation that progresses to fibrosis.

METHODS

Whole-exome sequencing, Sanger sequencing, mass spectrometry and western blotting were performed to identify and characterize the pathogenic HCK mutation. Dysregulation of mutant HCK was confirmed ex vivo in primary cells and in vitro in transduced cell lines.

RESULTS

Mutant HCK lacking the C-terminal inhibitory tyrosine Tyr522 exhibited increased kinase activity and enhanced myeloid cell priming, migration and effector functions, such as production of the inflammatory cytokines IL-1β, IL-6, IL-8 and TNFα and production of reactive oxygen species. These aberrant functions were reflected by inflammatory leukocyte infiltration of the lungs and skin. Moreover, an overview of the clinical course of the disease, including therapies, provides evidence for the therapeutic efficacy of the Janus kinase (JAK) 1/2 inhibitor ruxolitinib in inflammatory lung disease.

CONCLUSION

We propose HCK-driven pulmonary and cutaneous vasculitis as a novel autoinflammatory disorder of IEI.

Neutrophil elastase promotes macrophage cell adhesion and cytokine production through the integrin-Src kinases pathway

There are a number of respiratory diseases characterized by the presence of excess neutrophil elastase (NE) activity in tissues, including cystic fibrosis and chronic obstructive pulmonary disease (COPD). NE is considered a primary contributor to disease development, but the precise mechanism has yet to be fully determined. We hypothesized that NE alters the function of macrophages (Mɸ) which play a critical role in many physiological processes in healthy lungs. We demonstrate that monocyte-derived Mɸ exposed to NE releases active matrix metalloproteinases (MMPs), increase expression of pro-inflammatory cytokines TNFα, IL-1β, and IL-8, and reduce capacity to phagocytose bacteria. Changes in Mɸ function following NE treatment were accompanied by increased adhesion and cytoskeleton re-arrangement, indicating the possibility of integrin involvement. To support this observation, we demonstrate that NE induces phosphorylation of kinases from the Src kinase family, a hallmark of integrin signaling activation. Moreover, pretreatment of Mɸ with a specific Src kinase inhibitor, PP2 completely prevents NE-induced pro-inflammatory cytokine production. Taken together these findings indicate that NE participates in lung destruction not only through direct proteolytic degradation of matrix proteins, but also through activation of Mɸ inflammatory and proteolytic functions.

RV568, a narrow-spectrum kinase inhibitor with p38 MAPK-α and -γ selectivity, suppresses COPD inflammation

Novel anti-inflammatory approaches targeting chronically activated kinase pathways in chronic obstructive pulmonary disease (COPD) are needed. We evaluated RV568, a p38 mitogen-activated protein kinase-α and -γ and SRC family kinase inhibitor, in cellular and in vivo models relevant to COPD and examined its safety and efficacy in COPD patients.The anti-inflammatory activities of RV568 were tested in primary cultured monocytes, macrophages and bronchial epithelial cells and in vivo in lipopolysaccharide and cigarette smoke-exposed murine models. RV568 was evaluated in a 14-day trial in COPD patients.RV568 showed potent anti-inflammatory effects in monocytes and macrophages, which were often greater than those of corticosteroids or the p38 inhibitor Birb796. RV568 combined with corticosteroid had anti-inflammatory effects suggestive of a synergistic interaction in poly I:C-stimulated BEAS-2B cells and in the cigarette smoke model. In COPD patients, inhaled RV568 (50 µg and 100 µg) improved pre-bronchodilator forced expiratory volume in 1 s (69 mL and 48 mL respectively) and significantly reduced sputum malondialdehyde (p<0.05) compared to placebo, although there were no changes in sputum cell counts. Adverse events during RV568 and placebo treatment were similar.RV568 shows potent anti-inflammatory effects on cell and animal models relevant to COPD. RV568 was well-tolerated and demonstrated a modest clinical benefit in a 14-day COPD clinical trial.

Kinases as Novel Therapeutic Targets in Asthma and Chronic Obstructive Pulmonary Disease

Multiple kinases play a critical role in orchestrating the chronic inflammation and structural changes in the respiratory tract of patients with asthma and chronic obstructive pulmonary disease (COPD). Kinases activate signaling pathways that lead to contraction of airway smooth muscle and release of inflammatory mediators (such as cytokines, chemokines, growth factors) as well as cell migration, activation, and proliferation. For this reason there has been great interest in the development of kinase inhibitors as anti-inflammatory therapies, particular where corticosteroids are less effective, as in severe asthma and COPD. However, it has proven difficult to develop selective kinase inhibitors that are both effective and safe after oral administration and this has led to a search for inhaled kinase inhibitors, which would reduce systemic exposure. Although many kinases have been implicated in inflammation and remodeling of airway disease, very few classes of drug have reached the stage of clinical studies in these diseases. The most promising drugs are p38 MAP kinases, isoenzyme-selective PI3-kinases, Janus-activated kinases, and Syk-kinases, and inhaled formulations of these drugs are now in development. There has also been interest in developing inhibitors that block more than one kinase, because these drugs may be more effective and with less risk of losing efficacy with time. No kinase inhibitors are yet on the market for the treatment of airway diseases, but as kinase inhibitors are improved from other therapeutic areas there is hope that these drugs may eventually prove useful in treating refractory asthma and COPD.

Discovery of Narrow Spectrum Kinase Inhibitors: New Therapeutic Agents for the Treatment of COPD and Steroid-Resistant Asthma

The discovery of a novel series of therapeutic agents that has been designed and optimized for treating chronic obstructive pulmonary disease is reported. The pharmacological strategy was based on the identification of compounds that inhibit a defined subset of kinase enzymes modulating inflammatory processes that would be effective against steroid refractory disease and exhibit a sustained duration of action after inhaled delivery.

Hematopoietic cell kinase (HCK) as a therapeutic target in immune and cancer cells

The hematopoietic cell kinase (HCK) is a member of the SRC family of cytoplasmic tyrosine kinases (SFKs), and is expressed in cells of the myeloid and B-lymphocyte cell lineages. Excessive HCK activation is associated with several types of leukemia and enhances cell proliferation and survival by physical association with oncogenic fusion proteins, and with functional interactions with receptor tyrosine kinases. Elevated HCK activity is also observed in many solid malignancies, including breast and colon cancer, and correlates with decreased patient survival rates. HCK enhances the secretion of growth factors and pro-inflammatory cytokines from myeloid cells, and promotes macrophage polarization towards a wound healing and tumor-promoting alternatively activated phenotype. Within tumor associated macrophages, HCK stimulates the formation of podosomes that facilitate extracellular matrix degradation, which enhance immune and epithelial cell invasion. By virtue of functional cooperation between HCK and bona fide oncogenic tyrosine kinases, excessive HCK activation can also reduce drug efficacy and contribute to chemo-resistance, while genetic ablation of HCK results in minimal physiological consequences in healthy mice. Given its known crystal structure, HCK therefore provides an attractive therapeutic target to both, directly inhibit the growth of cancer cells, and indirectly curb the source of tumor-promoting changes in the tumor microenvironment.

Strategic applications of gene expression: from drug discovery/development to bedside

Gene expression is useful for identifying the molecular signature of a disease and for correlating a pharmacodynamic marker with the dose-dependent cellular responses to exposure of a drug. Gene expression offers utility to guide drug discovery by illustrating engagement of the desired cellular pathways/networks, as well as avoidance of acting on the toxicological pathways. Successful employment of gene-expression signatures in the later stages of drug development depends on their linkage to clinically meaningful phenotypic characteristics and requires a biologically meaningful mechanism combined with a stringent statistical rigor. Much of the success in clinical drug development is hinged on predefining the signature genes for their fitness for purposes of application. Specific examples are highlighted to illustrate the breadth and depth of the potential utility of gene-expression signatures in drug discovery and clinical development to targeted therapeutics at the bedside.

Systems analysis of eleven rodent disease models reveals an inflammatome signature and key drivers

A common inflammatome signature, as well as disease-specific expression patterns, was identified from 11 different rodent inflammatory disease models. Causal regulatory networks and the drivers of the inflammatome signature were uncovered and validated.

Representative inflammatome gene signatures, as well as disease model-specific gene signatures, were identified from 12 gene expression profiling data sets derived from 9 different tissues isolated from 11 rodent inflammatory disease models.

The inflammatome signature is highly enriched for immune response-related genes, disease causal genes, and drug targets.

Regulatory relationships among the inflammatome signature genes were examined in over 70 causal networks derived from a number of large-scale genetic studies of multiple diseases, and the potential key drivers were uncovered and validated prospectively.

Over 70% of the inflammatome signature genes and over 50% of the key driver genes have not been reported in previous studies of common signatures in inflammatory conditions.

Common inflammatome gene signatures as well as disease-specific signatures were identified by analyzing 12 expression profiling data sets derived from 9 different tissues isolated from 11 rodent inflammatory disease models. The inflammatome signature significantly overlaps with known drug targets and co-expressed gene modules linked to metabolic disorders and cancer. A large proportion of genes in this signature are tightly connected in tissue-specific Bayesian networks (BNs) built from multiple independent mouse and human cohorts. Both the inflammatome signature and the corresponding consensus BNs are highly enriched for immune response-related genes supported as causal for adiposity, adipokine, diabetes, aortic lesion, bone, muscle, and cholesterol traits, suggesting the causal nature of the inflammatome for a variety of diseases. Integration of this inflammatome signature with the BNs uncovered 151 key drivers that appeared to be more biologically important than the non-drivers in terms of their impact on disease phenotypes. The identification of this inflammatome signature, its network architecture, and key drivers not only highlights the shared etiology but also pinpoints potential targets for intervention of various common diseases.

Hematopoietic cell kinase gene polymorphisms and the risk of chronic obstructive pulmonary disease in a Chinese population

Hematopoietic cell kinase (Hck), a Src family kinase, has been recently suggested to be implicated in the pathogenesis of chronic obstructive pulmonary disease (COPD). The present study aims to analyze the association of polymorphism of Hck gene with COPD in a Chinese population. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and polymerase chain reaction-sequence-specific primer method (PCR-SSP) were used to type Hck polymorphisms in 120 patients with COPD and 100 healthy controls. There were significant differences in the genotype and allele distribution of -627 G/T polymorphism in Hck gene between cases and controls (P<.05). The GT genotype was associated with a significantly increased risk of COPD as compared with the GG genotype (Odds ratio [OR]=2.60, 95% confidence interval [CI]: 1.39-4.48; P=.002). Moreover, individuals carrying T allele had a significantly higher risk for developing COPD than those carrying G allele (OR=2.19, 95% CI: 1.26-3.79; P=.005). In haplotype analysis, compared with CG(deletion) haplotype, CT(insertion) haplotype was associated with a significantly increased risk of COPD (OR=2.66, 95% CI: 1.22-5.78; P=.011). These findings suggest the Hck gene polymorphisms may contribute to COPD susceptibility in Chinese population.

Oxidative stress augments toll-like receptor 8 mediated neutrophilic responses in healthy subjects

Background

Excessive oxidative stress has been reported to be generated in inflamed tissues and contribute to the pathogenesis of inflammatory lung diseases, exacerbations of which induced by viral infections are associated with toll-like receptor (TLR) activation. Among these receptors, TLR8 has been reported as a key receptor that recognizes single-strand RNA virus. However, it remains unknown whether TLR8 signaling is potentiated by oxidative stress. The aim of this study is to examine whether oxidative stress modulates TLR8 signaling in vitro.

Methods

Human peripheral blood neutrophils were obtained from healthy non-smokers and stimulated with TLR 7/8 agonist imidazoquinoline resiquimod (R848) in the presence or absence of hydrogen peroxide (H₂O₂). Neutrophilic responses including cytokine release, superoxide production and chemotaxis were examined, and the signal transduction was also analyzed.

Results

Activation of TLR8, but not TLR7, augmented IL-8 release. The R848-augmented IL-8 release was significantly potentiated by pretreatment with H₂O₂ (p < 0.01), and N-acetyl-L-cysteine reversed this potentiation. The combination of H₂O₂ and R848 significantly potentiated NF-kB phosphorylation and IkBα degradation. The H₂O₂-potentiated IL-8 release was suppressed by MG-132, a proteosome inhibitor, and by dexamethasone. The expressions of TLR8, myeloid differentiation primary response gene 88 (MyD88), and tumor necrosis factor receptor-associated factor 6 (TRAF6) were not affected by H₂O₂.

Conclusion

TLR8-mediated neutrophilic responses were markedly potentiated by oxidative stress, and the potentiation was mediated by enhanced NF-kB activation. These results suggest that oxidative stress might potentiate the neutrophilic inflammation during viral infection.