Visfatin Is Actively Secreted In Vitro From U-937 Macrophages, but Only Passively Released From 3T3-L1 Adipocytes and HepG2 Hepatocytes

Abstract

Visfatin is a multi-functional molecule that can act intracellularly and extracellularly as an adipokine, cytokine and enzyme. One of the main questions concerning visfatin is the mechanism of its secretion; whether, how and from which cells visfatin is released. The objective of this in vitro study was to observe the active secretion of visfatin from 3T3-L1 preadipocytes and adipocytes, HepG2 hepatocytes, U-937, THP-1 and HL-60 monocytes and macrophages. The amount of visfatin in media and cell lysate was always related to the intracellular enzyme, glyceraldehyde-3-phosphate dehydrogenase (GAPDH), to exclude the passive release of visfatin. Visfatin was not found in media of 3T3-L1 preadipocytes. In media of 3T3-L1 adipocytes and HepG2 hepatocytes, the ratio of visfatin to the amount of GAPDH was identical to cell lysates. Hence, it is likely that these cells do not actively secrete visfatin in a significant manner. However, we found that significant producers of visfatin are differentiated macrophages and that the amount of secreted visfatin depends on used cell line and it is affected by the mode of differentiation. Results show that 3T3-L1 adipocytes and HepG2 hepatocytes released visfatin only passively during the cell death. U-937 macrophages secrete visfatin in the greatest level from all of the tested cell lines.

Nuclear transport of nicotinamide phosphoribosyltransferase is cell cycle–dependent in mammalian cells, and its inhibition slows cell growth

“…Western blotting was performed and evaluated as described previously (61). Each lysate was resolved by SDS-PAGE (40 g protein/lane, 10% gel) (Mini-PROTEAN Tetra Cell; Bio-Rad).…”

NAMPT and NAPRT serum levels predict response to anti-TNF therapy in inflammatory bowel disease

“…The source of eNAMPT and eNAPRT in blood is at present unknown, and it is likely to derive from immune cells. For example, myeloid cells are an important source for eNAMPT, as reported in several manuscripts (10,14,28). For example, myeloid cells are an important source for eNAMPT, as reported in several manuscripts (10,14,28).…”

“…For example, myeloid cells are an important source for eNAMPT, as reported in several manuscripts (10,14,28). For example, myeloid cells are an important source for eNAMPT, as reported in several manuscripts (10,14,28). On the other hand, eNAMPT and eNAPRT are also known to be released by the adipose tissue, which could be a further contributor.…”

Complex Positive Effects of SGLT-2 Inhibitor Empagliflozin in the Liver, Kidney and Adipose Tissue of Hereditary Hypertriglyceridemic Rats: Possible Contribution of Attenuation of Cell Senescence and Oxidative Stress

“…Mouse 3T3-L1 preadipocytes were purchased from the American Type Culture Collection and maintained in Dulbecco’s modified Eagle’s medium (DMEM) containing 4.5 g/L d -glucose and 1 mM sodium pyruvate (Gibco, Grand Island, NY, USA), supplemented with 10% foetal bovine serum (Gibco, Grand Island, NY, USA), 4 mM l -glutamine (Gibco, Grand Island, NY, USA), and the mixture of 100 U/mL penicillin and 100 μg/mL streptomycin sulphate (Sigma-Aldrich, St. Louis, MO, USA). The cells were differentiated into mature adipocytes, as described previously [ 17 , 80 ], by the addition of differentiation mixture 0.5 mM 3-isobutyl-1-methylxanthine (IBMX; Sigma-Aldrich, St. Louis, MO, USA), 0.4 µM dexamethasone (Dex; Sigma-Aldrich, St. Louis, MO, USA), 1.7 µM insulin (Ins; figure) and 25 mM HEPES (Sigma-Aldrich, St. Louis, MO, USA). 3T3-L1 cells were differentiated into mature adipocytes for 11 days.…”