Role of adiponectin in sphingosine-1-phosphate induced airway hyperresponsiveness and inflammation

Metformin Alleviates Airway Hyperresponsiveness in a Mouse Model of Diet-Induced Obesity

Obese asthma is a unique phenotype of asthma characterized by non-allergic airway hyperresponsiveness (AHR) and inflammation which responds poorly to standard asthma therapy. Metformin is an oral hypoglycemic drug with insulin-sensitizing and anti-inflammatory properties. The objective of the current study was to test the effect of metformin on AHR in a mouse model of diet-induced obesity (DIO). We fed 12-week-old C57BL/6J DIO mice with a high fat diet for 8 weeks and treated them with either placebo (control, n = 10) or metformin (n = 10) added in drinking water (300 mg/kg/day) during the last 2 weeks of the experiment. We assessed AHR, metabolic profiles, and inflammatory markers after treatments. Metformin did not affect body weight or fasting blood glucose, but significantly reduced serum insulin (p = 0.0117). Metformin reduced AHR at 30 mg/ml of methacholine challenge (p = 0.0052) without affecting baseline airway resistance. Metformin did not affect circulating white blood cell counts or lung cytokine mRNA expression, but modestly decreased circulating platelet count. We conclude that metformin alleviated AHR in DIO mice. This finding suggests metformin has the potential to become an adjuvant pharmacological therapy in obese asthma.

Regulatory Peptides in Asthma

Numerous regulatory peptides play a critical role in the pathogenesis of airway inflammation, airflow obstruction and hyperresponsiveness, which are hallmarks of asthma. Some of them exacerbate asthma symptoms, such as neuropeptide Y and tachykinins, while others have ameliorating properties, such as nociception, neurotensin or β-defensin 2. Interacting with peptide receptors located in the lungs or on immune cells opens up new therapeutic possibilities for the treatment of asthma, especially when it is resistant to available therapies. This article provides a concise review of the most important and current findings regarding the involvement of regulatory peptides in asthma pathology.

Proteolytic enzyme and adiponectin receptors as potential targets for COVID-19 therapy

The coronavirus disease 2019 (COVID-19) pandemic requires not only the creation of vaccines to prevent the spread of the disease, but also the development of novel drugs aimed at reducing viral load, suppressing an excessive immune response and preventing the severe complications such as lung fibrosis and acute respiratory distress syndrome. One of the promising targets for studying the development of pneumonia, systemic inflammation and disseminated intravascular coagulation in COVID-19 is the plasminogen activator system. In patients with a severe disease course, impaired activity or expression of plasminogen activators significantly increases the blood level of D-dimer and fibrinogen, as well as correlates with intravascular coagulation and thrombus formation. The second promising target for studying the pathogenesis of COVID-19 is the adiponectin/T-cadherin system: adiponectin is able to reduce the content of pro-inflammatory cytokines, the increase of which is characteristic of COVID-19, and stimulate the production of an anti-inflammatory cytokine interleukin-10. The review describes the role of plasminogen and T-cadherin activators in their possible participation in the development of pulmonary fibrosis in COVID-19 and hemostasis regulation, as well as cardio- and vasculoprotective function of adiponectin and its receptor, T-cadherin.

Functional Changes Induced by Orexin A and Adiponectin on the Sympathetic/Parasympathetic Balance

Obesity and lifestyle-related diseases are major problems faced by people in developed nations. Although exercise training prevents the progression of diabetes and obesity, the motivation for exercise is generally low in obese animals and humans. The autonomic nervous system (SNA) plays a crucial role in the regulation of eating behavior. Moreover, the SNA is involved in the body temperature regulation that is strictly related to body weight control, in accordance with the “thermoregulatory hypothesis” of food intake. Some neuronal peptides and hormones, like orexins and adiponectin, are also involved in the regulation of locomotion activity as well as food intake and metabolic rate. Furthermore, adiponectin as well as orexin A are involved in the control of body temperature, food intake and therefore in obesity-related diseases. The aim of this study was to investigate the changes in body temperature (Tc), and heart rate (HR) after an intracerebroventricular (ICV) injection of orexin A and adiponectin in animal model. The results of this study show that the orexin A levels are likely involved in the increase of Tc and HR. It is also clear that there is not a correlation between these parameters and adiponectin levels. Further studies are needed to assess adiponectin actions and outcome in the central nervous system in terms of energy expenditure, body temperature, heart rate and physical activity performance regulation.

Adiponectin down-regulates CREB and inhibits proliferation of A549 lung cancer cells

INTRODUCTION

Adipokines are known to play a relevant role in a number of cancer related molecular pathways. Adiponectin is a major adipokine with anti-inflammatory and beneficial metabolic actions. Furthermore, it has been shown to exert anti-carcinogenic effects in various tumor models and some clinical studies suggested an inverse relationship between circulating levels of adiponectin and an increased risk for development of malignancies. On the other hand, the cyclic AMP response element binding (CREB) transcription factor has been clearly linked to lung cancer.

METHODS

we analyzed cell proliferation, cell cycle of A549 cells treated with adiponectin as well as CREB activation status in human lung adenocarcinoma A549 cells and in non-small cell lung cancer (NSCLC) samples.

RESULTS

adiponectin treatment, at concentrations ranging between 5 and 50 μg/ml mimicking human serum levels, has a significant effect on reducing tumor cell proliferation of A549 cells, mainly by altering cell cycle progression. Importantly, we provide evidence that adiponectin clearly inhibits in a dose- and time-dependent manner CREB phosphorylation (activation) and, at least in part, also the level of CREB protein itself, preceding and accompanying the anti-proliferative effects in response to adiponectin. Moreover, in agreement with previous studies demonstrating that CREB over-expression occurs in many tumors, we also show by western-blotting from lung specimen that CREB is significantly up-regulated in NSCLC samples compared to adjacent normal tissues from six patients.

CONCLUSIONS

Overall, our results represent the first evidence of CREB inhibition by adiponectin and may provide new insight into therapeutic strategies for lung cancer.

The burden of obesity in asthma and COPD: Role of adiponectin

The influence of obesity on development, severity and prognosis of both asthma and COPD is attracting growing interest. The impact of obesity on the respiratory system ranges from structural modifications (decline of total lung capacity) to humoral alterations. Adipose tissue strongly contributes to the establishment of an inflammatory state being an important source of adipokines. Amongst adipokines, adiponectin is an important component of organ cross talk with adipose tissue exerting protective effects on a variety of pathophysiological processes. Adiponectin is secreted in serum where it abundantly circulates as complexes of different molecular weight. Adiponectin properties are mediated by specific receptors that are widely expressed with AdipoR1, AdipoR2, and T-cadherin being present on epithelial and endothelial pulmonary cells indicating a functional role on lung physiology. In COPD, mild to moderate obesity has been shown to have protective effects on patient's survival, while a higher mortality rate has been observed in patients with low BMI. A specific cluster of obese patients has been identified; in this group, asthma features are particularly severe and difficult to treat. Better understanding of the molecular mechanisms at the base of cross talk among different tissues and organs will lead to identification of new targets for both diagnosis and treatment of asthma and COPD.

Gene-based analysis identified the gene ZNF248 is associated with late-onset asthma in African Americans

BACKGROUND

Late-onset asthma (LOA) has distinct characteristics and its pathogenesis might rely on unique pathways. Although current studies are focused primarily on childhood asthma, more research is needed to show the mechanisms underlying LOA.

OBJECTIVE

To conduct genomewide association analysis and gene-based analysis to identify single-nucleotide polymorphisms and genes associated with LOA.

METHODS

The Women's Health Initiative (WHI) observational cohort and the Multi-Ethnic Study of Atherosclerosis (MESA) were used to identify subjects with LOA. The association between LOA and body mass index and smoking was evaluated. In the discovery stage of the genetic analysis, 1,218 African American subjects from WHI with genotype data (271 cases and 947 controls) were used for single-nucleotide polymorphism and gene-based association analyses. Significant or suggestive results were subsequently investigated in an independent African American population from MESA (38 cases and 806 controls).

RESULTS

In WHI, the relative odds for LOA in obese vs normal-weight subjects was 2.55 (95% confidence interval 1.74-3.76). Ever smokers also had greater odds for LOA compared with never smokers (odds ratio 1.59, 95% confidence interval 1.21-2.09). The same trends were observed in MESA. In WHI, 6 single-nucleotide polymorphisms were associated with LOA at a genomewide-suggestive significance level (P < 1.0 × 10(-5)). The gene ZNF248 was associated with LOA and reached genomewide significance (P = 4.0 × 10(-7)). In MESA, the association between ZNF248 and LOA was successfully replicated (P = .015).

CONCLUSION

Smoking and obesity are risk factors for LOA. ZNF248 confers increased susceptibility to LOA in African Americans.