Polyamines Are Present in Mast Cell Secretory Granules and Are Important for Granule Homeostasis

Abstract

BackgroundMast cell secretory granules accommodate a large number of components, many of which interact with highly sulfated serglycin proteoglycan (PG) present within the granules. Polyamines (putrescine, spermidine and spermine) are absolutely required for the survival of the vast majority of living cells. Given the reported ability of polyamines to interact with PGs, we investigated the possibility that polyamines may be components of mast cell secretory granules.Methodology/Principal FindingsSpermidine was released by mouse bone marrow derived mast cells (BMMCs) after degranulation induced by IgE/anti-IgE or calcium ionophore A23187. Additionally, both spermidine and spermine were detected in isolated mouse mast cell granules. Further, depletion of polyamines by culturing BMMCs with α-difluoromethylornithine (DFMO) caused aberrant secretory granule ultrastructure, impaired histamine storage, reduced serotonin levels and increased β-hexosaminidase content. A proteomic approach revealed that DFMO-induced polyamine depletion caused an alteration in the levels of a number of proteins, many of which are connected either with the regulated exocytosis or with the endocytic system.Conclusions/SignificanceTaken together, our results show evidence that polyamines are present in mast cell secretory granules and, furthermore, indicate an essential role of these polycations during the biogenesis and homeostasis of these organelles.

Active Caspase-3 Is Stored within Secretory Compartments of Viable Mast Cells

“…Mice (8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18) wk old) were all on C57BL/6J genetic background, and all animal experiments were approved by the local ethical committee. mM NaCl, 5 mM KCl, 1.4 mM CaCl 2 , 1 mM MgCl 2 , 5.6 mM glucose, 10 mM HEPES, and 0.1% BSA [pH 7.4]) and stimulated with TNP-OVA (0.4 mg/ml).…”

“…Granule-enriched fractions were obtained from BMMCs by soft disruption in a bath sonicator and density centrifugation in Percoll, as previously described (10).…”

Anaplerotic Accumulation of Tricarboxylic Acid Cycle Intermediates as Well as Changes in Other Key Metabolites During Heterotopic Ossification

“…However, recent studies have shown that the polyamines spermine and spermidine are an essential part of the granule component of mast cells, and play an essential role in the biogenesis and homeostasis of these organelles [Garcia‐Faroldi et al, 2010]. We have previously shown that mast cells are a critical component of HO and when these cells are eliminated HO is severely inhibited [Salisbury et al, 2011].…”

Vesicular Polyamine Transporter Mediates Vesicular Storage and Release of Polyamine from Mast Cells

“…These polyamines are stored in mast cell secretory granules, appear in the extracellular space through A23187-evoked Ca 2ϩ -dependent processes, and are thought to be involved in biogenesis and homeostasis of secretory granules (4). Furthermore, it has been reported that spermine and spermidine, when applied to mast cells extracellularly, facilitate synthesis and release of histamine from mast cells (7)(8)(9)(10)(11).…”

“…Furthermore, it has been reported that spermine and spermidine, when applied to mast cells extracellularly, facilitate synthesis and release of histamine from mast cells (7)(8)(9)(10)(11). Spermine and spermidine are also involved in storage and/or release of histamine and serotonin in the mast cell granules (4,12). Although there are numerous studies on polyamine function in mast cells, it remains unclear how these polyamines are loaded into mast cell granules and discharged into the extracellular space upon stimulation.…”