Omentin-A Novel Adipokine in Respiratory Diseases

Abstract

Adipokines, secreted by the adipose tissue, are extensively involved in the regulation and maintenance of various physiological and pathological processes, including insulin sensitivity, energy expenditure, glucose and lipid metabolism, inflammatory activity, neuroendocrine activity, immunity, cancer, homeostasis, angiogenesis, cardiovascular function, breeding and bone metabolism, and all functions of the endocrine-reproductive system axis. Omentin is a recently identified adipokine, which has become a research hotspot due to its pleiotropic effects on various diseases. However, the specific receptor for omentin has not been identified so far. In this study, we report that omentin levels fluctuate in various diseases. In addition, we have focused on the pleiotropic roles of omentin in pulmonary diseases, as it may act as a biomarker for malignant pleural mesothelioma (MPM) and is related to disease severity. Omentin may play significant roles in other pulmonary diseases, such as asthma, obstructive sleep apnea syndrome (OSAS), pulmonary arterial hypertension (PAH), acute respiratory distress syndrome (ARDS), and chronic obstructive pulmonary disease (COPD). This review summarizes the advances in current knowledge and future trends, which may provide a concise and general view on omentin and its effects on pulmonary biology.

Keywords: ARDS; COPD; MPM; OSAS; PAH; adipokines; adipose tissue; asthma; omentin; respiratory diseases.

Figure 1

The protective mechanisms of omentin in various pathophysiological processes. AMPK, Adenosine 5′-monophosphate (AMP)-activated protein kinase; eNOS, endothelial nitric oxide synthase; COX-2, cyclooxygenase-2; ERK, extracellular regulated protein kinases; TNF-α, tumor necrosis factor-α; IL-6, interleukin-6; MCP-1, monocyte chemotactic protein-1; PI3K, phosphatidylinositol 3 kinase; AKT, protein kinase B; OPG, osteoprotegerin; RANKL, receptor activator for nuclear factor κB ligand; CVSMC, calcifying vascular smooth muscle cells; VCAM-1, vascular cell adhesion molecule-1; ICAM-1, intracellular adhesion molecule-1; NOX, NADPH oxidase; JNK, Jun N-terminal kinase; HSP27, heat shock protein 27; SMC, smooth muscle cell; NF-κB, nuclear factor-κB.