The Cytokine Nicotinamide Phosphoribosyltransferase (eNAMPT; PBEF; Visfatin) Acts as a Natural Antagonist of C-C Chemokine Receptor Type 5 (CCR5).

Simone Torretta,Dmitry Lim,Ambra A Grolla,Sara Boumya,Cristina Travelli,Armando A Genazzani,Giorgia Colombo

doi:10.3390/cells9020496

Simone Torretta, Dmitry Lim + Show 5 more

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https://doi.org/10.3390/cells9020496

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Abstract

(1) Background: Extracellular nicotinamide phosphoribosyltrasferase (eNAMPT) is released by various cell types with pro-tumoral and pro-inflammatory properties. In cancer, eNAMPT regulates tumor growth through the activation of intracellular pathways, suggesting that it acts through a putative receptor, although its nature is still elusive. It has been shown, using surface plasma resonance, that eNAMPT binds to the C-C chemokine receptor type 5 (CCR5), although the physiological meaning of this finding is unknown. The aim of the present work was to characterize the pharmacodynamics of eNAMPT on CCR5. (2) Methods: HeLa CCR5-overexpressing stable cell line and B16 melanoma cells were used. We focused on some phenotypic effects of CCR5 activation, such as calcium release and migration, to evaluate eNAMPT actions on this receptor. (3) Results: eNAMPT did not induce ERK activation or cytosolic Ca2+-rises alone. Furthermore, eNAMPT prevents CCR5 internalization mediated by Rantes. eNAMPT pretreatment inhibits CCR5-mediated PKC activation and Rantes-dependent calcium signaling. The effect of eNAMPT on CCR5 was specific, as the responses to ATP and carbachol were unaffected. This was strengthened by the observation that eNAMPT inhibited Rantes-induced Ca2+-rises and Rantes-induced migration in a melanoma cell line. (4) Conclusions: Our work shows that eNAMPT binds to CCR5 and acts as a natural antagonist of this receptor.

Highlights

Extracellular nicotinamide phosphoribosyltrasferase, known as PBEF or visfatin, is the secreted form of NAMPT (EC 2.4.2.12), a key enzyme involved in maintaining the balance of NAD and adenosine triphosphate (ATP) levels in cells [1]
We show that Extracellular nicotinamide phosphoribosyltrasferase (eNAMPT) binds to chemokine receptor type 5 (CCR5) in cancer cells and acts as a natural antagonist of this receptor
To evaluate whether the effect of eNAMPT on calcium signaling was specific for CCR5, we evaluated its effect on Ca2+ signaling induced by ATP or carbachol

Summary

Introduction

Extracellular nicotinamide phosphoribosyltrasferase (eNAMPT), known as PBEF or visfatin, is the secreted form of NAMPT (EC 2.4.2.12), a key enzyme involved in maintaining the balance of NAD and ATP levels in cells [1]. NAMPT, starting from nicotinamide (Nam), adenosine triphosphate (ATP). Phosphoribosyl pyrophosphate (PRPP), catalyzes the production of nicotinamide mononucleotide (NMN), a key precursor of NAD in mammalian cells. Different cell types secret NAMPT in the extracellular space, where it is considered a metabokine with pro-inflammatory and pro-tumoral activity [2,3]. ENAMPT is overexpressed in several disorders, including cancer [4,5] where eNAMPT controls angiogenesis, tumor growth and metastasis [6,7]. The mechanism by which eNAMPT exerts its function is still an open debate.

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