Leptin receptor (Ob‐R) expression is induced in peripheral blood mononuclear cells by in vitro activation and in vivo in HIV‐infected patients

• Published in: Clinical and experimental immunology Vol. 129; no. 1; pp. 119 - 124
• Main Authors: SÁNCHEZ‐MARGALET, V., MARTÍN‐ROMERO, C., GONZÁLEZ‐YANES, C., GOBERNA, R., RODRÍGUEZ‐BAÑO, J., MUNIAIN, M. A.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Science Ltd 01.07.2002; Blackwell; Oxford University Press; Blackwell Science Inc
• Subjects: Adolescent; Adult; Biological and medical sciences; Carrier Proteins - biosynthesis; Carrier Proteins - drug effects; Carrier Proteins - genetics; Carrier Proteins - physiology; cell activation HIV leptin receptor lymphocytes PBMC; Cells, Cultured - metabolism; Child; Concanavalin A - pharmacology; Female; Gene Expression Regulation - drug effects; Hepatitis C - complications; Hepatitis C - immunology; HIV Infections - complications; HIV Infections - immunology; Human viral diseases; Humans; Infectious diseases; Leptin - pharmacology; Leptin - physiology; Lymphocyte Activation - drug effects; Lymphocyte Activation - genetics; Male; Medical sciences; Original; Phosphorylation; Phytohemagglutinins - pharmacology; Protein Isoforms - biosynthesis; Protein Isoforms - drug effects; Protein Isoforms - genetics; Protein Isoforms - physiology; Protein Processing, Post-Translational; Receptors, Cell Surface; Receptors, Leptin; Recombinant Proteins - pharmacology; RNA, Messenger - biosynthesis; Signal Transduction - drug effects; T-Lymphocytes - drug effects; T-Lymphocytes - metabolism; Viral diseases; Viral diseases of the lymphoid tissue and the blood. Aids; Human; Immunopathology; Immune response; Immunomodulation; Retroviridae; AIDS; Immune deficiency; Lentivirus; Infection; Virus; Viral disease; Leptin; Human immunodeficiency virus; Lymphocyte; Biological receptor
• ISSN: 0009-9104; 1365-2249
• DOI: 10.1046/j.1365-2249.2002.01900.x

SUMMARY Leptin, the Ob gene product, is an adipocyte hormone that centrally regulates weight control. In addition, other effects of leptin in peripheral tissues have been described. Thus, leptin has been found to regulate reproduction, haematopoiesis and immune function. We have found recently that leptin has a stimulatory effect on human peripheral blood mononuclear cells (PBMC). Monocytes are activated by leptin alone whereas T lymphocytes need a suboptimal stimulus of PHA or ConA before further activation by leptin. These effects are mediated by the long isoform of the leptin receptor, which has been shown to trigger signalling in PBMC. In fact, we have found that human leptin stimulates Janus kinase (JAK)‐signal transducer and activator of transcription (STAT), phosphatidylinositol 3‐kinase (PI3K) and mitogen‐activated protein kinase (MAPK) pathways in PBMC. In order to assess possible regulation of the long isoform of the leptin receptor (Ob‐R) in mononuclear cells upon activation, we have studied the expression of Ob‐R by RT‐PCR and Western blotting in PBMC activated in vitro by PHA or ConA and in vivo in HIV‐infected patients. We have found that in vitro activation and in vivo HIV infection correlates with an increase in leptin receptor expression in PBMC. Moreover, the leptin receptor is tyrosine phosphorylated in PBMC from HIV‐infected patients, suggesting that the leptin receptor is activated. These results are consistent with the suggested role of leptin in modulating the immune response.