Osteopontin Deficiency Protects against Airway Remodeling and Hyperresponsiveness in Chronic Asthma

The traditional Chinese herbal formula ASHMI inhibits allergic lung inflammation in antigen-sensitized and antigen-challenged aged mice

BACKGROUND

Although asthma is typically characterized as a childhood disease, it can develop later in life. Older asthmatic patients may be at increased risk for corticosteroid adverse effects. We developed a novel traditional Chinese medicine to treat asthma called antiasthma simplified herbal medicine intervention (ASHMI). Herbal products may offer safer adjunctive treatment for older asthmatic patients.

OBJECTIVE

To investigate the effects of ASHMI on characteristics of allergic asthma in an aged mouse model of asthma.

METHODS

BALB/c mice (6 weeks old [young] and 6, 12, and 18 months old [aged]) received ASHMI treatment before and during intraperitoneal ovalbumin sensitization and intratracheal challenges. The control groups were untreated, age-matched, ovalbumin-sensitized and ovalbumin-challenged mice (ovalbumin mice) and naive mice. After the final antigen challenge, airway pressure (defined as the time-integrated change in peak airway pressure) after acetylcholine provocation was measured, representing airway hyperresponsiveness, and bronchoalveolar lavage fluid, sera, lung tissues for histologic analysis, messenger RNA, and collagen were collected.

RESULTS

Mean time-integrated change in peak airway pressure values in 6-week-old and 6-, 12-, and 18-month-old ASHMI ovalbumin mice were significantly reduced compared with those of age-matched, nontreated ovalbumin mice. Bronchoalveolar lavage fluid eosinophil numbers were significantly lower in all ASHMI ovalbumin mice. Treatment with ASHMI of young and aged ovalbumin mice resulted in significantly decreased lung inflammation, detected via hematoxylin-eosin staining; airway mucous cell metaplasia, determined by means of periodic acid-Schiff staining; and messenger RNA copy numbers of the mucin gene MUC5AC. Levels of ovalbumin specific IgE and the T(H)2 cytokines interleukin 4 (IL-4), IL-5, and IL-13 in lung and splenocyte cultures were reduced. Interferon gamma secretion was increased. Treatment with ASHMI reduced collagen production.

CONCLUSION

Treatment with ASHMI reduces several features of asthma in aged antigen-sensitized and antigen-challenged mice.

Alcohol, signaling, and ECM turnover

Alcohol is recognized as a direct hepatotoxin, but the precise molecular pathways that are important for the initiation and progression of alcohol-induced tissue injury are not completely understood. The current understanding of alcohol toxicity to organs suggests that alcohol initiates injury by generation of oxidative and nonoxidative ethanol metabolites and via translocation of gut-derived endotoxin. These processes lead to cellular injury and stimulation of the inflammatory responses mediated through a variety of molecules. With continuing alcohol abuse, the injury progresses through impairment of tissue regeneration and extracellular matrix (ECM) turnover, leading to fibrogenesis and cirrhosis. Several cell types are involved in this process, the predominant being stellate cells, macrophages, and parenchymal cells. In response to alcohol, growth factors and cytokines activate many signaling cascades that regulate fibrogenesis. This mini-review brings together research focusing on the underlying mechanisms of alcohol-mediated injury in a number of organs. It highlights the various processes and molecules that are likely involved in inflammation, immune modulation, susceptibility to infection, ECM turnover and fibrogenesis in the liver, pancreas, and lung triggered by alcohol abuse.

Adenosine and osteopontin contribute to the development of chronic obstructive pulmonary disease

Chronic obstructive pulmonary disease (COPD) is a major health concern. Adenosine, a signaling molecule generated in response to cell stress, contributes to the pathogenesis of COPD. An established model of adenosine-mediated lung injury is the adenosine deaminase-deficient (Ada(-/-)) mouse. Osteopontin (OPN) is a chemokine that is produced following injury and is implicated in a variety of human pathologies, but its expression and role in the pathogenesis of COPD have not been examined. To investigate the role of OPN in a model of COPD, Ada(-/-) double-knockout mice were generated, and inflammation and air-space enlargement endpoints were examined. Results demonstrate that Ada(-/-) mice exhibit OPN-dependent neutrophilia, alveolar air-space enlargement, and increases in mediators of air-space enlargement. Furthermore, we demonstrate that patients with COPD have increased OPN expression within distal airways in association with clinical airway obstruction. These results suggest that OPN represents a novel biomarker and therapeutic target for patients with COPD.