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Mesenchymal Stem Cells Exhibit Regulated Exocytosis in Response to Chemerin and IGF.

Kumar JD, Holmberg C, Balabanova S, Borysova L, Burdyga T, Beynon R, Dockray GJ, Varro A - PLoS ONE (2015)

Bottom Line: The calcium ionophore, ionomycin, also rapidly increased secretion of TGFβig-h3 while inhibitors of translation (cycloheximide) or secretory protein transport (brefeldin A) had no effect, indicating secretion from preformed secretory vesicles.Inhibitors of the chemerin and IGF receptors specifically reduced the secretory response.Gene ontology analysis of proteins exhibiting regulated secretion indicated functions primarily associated with cell adhesion and in bioassays chemerin increased adhesion of MSCs and adhesion, proliferation and migration of myofibroblasts.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown St, Liverpool, United Kingdom.

ABSTRACT
Mesenchymal stem cells (MSCs) play important roles in tissue repair and cancer progression. Our recent work suggests that some mesenchymal cells, notably myofibroblasts exhibit regulated exocytosis resembling that seen in neuroendocrine cells. We now report that MSCs also exhibit regulated exocytosis. Both a G-protein coupled receptor agonist, chemerin, and a receptor tyrosine kinase stimulant, IGF-II, evoked rapid increases in secretion of a marker protein, TGFβig-h3. The calcium ionophore, ionomycin, also rapidly increased secretion of TGFβig-h3 while inhibitors of translation (cycloheximide) or secretory protein transport (brefeldin A) had no effect, indicating secretion from preformed secretory vesicles. Inhibitors of the chemerin and IGF receptors specifically reduced the secretory response. Confocal microscopy of MSCs loaded with Fluo-4 revealed chemerin and IGF-II triggered intracellular Ca2+ oscillations requiring extracellular calcium. Immunocytochemistry showed co-localisation of TGFβig-h3 and MMP-2 to secretory vesicles, and transmission electron-microscopy showed dense-core secretory vesicles in proximity to the Golgi apparatus. Proteomic studies on the MSC secretome identified 64 proteins including TGFβig-h3 and MMP-2 that exhibited increased secretion in response to IGF-II treatment for 30min and western blot of selected proteins confirmed these data. Gene ontology analysis of proteins exhibiting regulated secretion indicated functions primarily associated with cell adhesion and in bioassays chemerin increased adhesion of MSCs and adhesion, proliferation and migration of myofibroblasts. Thus, MSCs exhibit regulated exocytosis that is compatible with an early role in tissue remodelling.

No MeSH data available.


Related in: MedlinePlus

Enriched molecular functions, protein classes and biological processes in the MSC secretome.A, The main molecular functions shown by PANTHER for 62 proteins in the MSC secretome identified as “secreted” and as exhibiting increased abundance after IGF-II treatment. B. Enriched protein classes, C. Enriched biological processes. P, probability.
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pone.0141331.g003: Enriched molecular functions, protein classes and biological processes in the MSC secretome.A, The main molecular functions shown by PANTHER for 62 proteins in the MSC secretome identified as “secreted” and as exhibiting increased abundance after IGF-II treatment. B. Enriched protein classes, C. Enriched biological processes. P, probability.

Mentions: Gene ontology, functional enrichment and pathway analysis of the 64 proteins were performed using PANTHER with a significance threshold cut-off of p<0.05 for proteins identified as constituting the IGF-II-regulated MSC secretome. Analysis of enriched molecular functions showed 7 significantly enriched groups, the top being peptidase activity, represented for example by tissue inhibitor of metalloproteinases (TIMP) -1, -2, -3, and MMP-2 (Fig 3A). A total of 12 protein classes were significantly over-represented of which the top three were extracellular matrix proteins, signalling molecules and proteases (Fig 3B). Gene ontology analysis showed 17 significantly over-represented biological processes with cell adhesion, cell matrix adhesion and cell-cell adhesion as the top three (the top 12 are listed in Fig 3C). The only significant over-represented (>5) pathway was the integrin signalling pathway which was represented by 11 proteins on the regulated secretome list (p = 2.29E-08).


Mesenchymal Stem Cells Exhibit Regulated Exocytosis in Response to Chemerin and IGF.

Kumar JD, Holmberg C, Balabanova S, Borysova L, Burdyga T, Beynon R, Dockray GJ, Varro A - PLoS ONE (2015)

Enriched molecular functions, protein classes and biological processes in the MSC secretome.A, The main molecular functions shown by PANTHER for 62 proteins in the MSC secretome identified as “secreted” and as exhibiting increased abundance after IGF-II treatment. B. Enriched protein classes, C. Enriched biological processes. P, probability.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4626093&req=5

pone.0141331.g003: Enriched molecular functions, protein classes and biological processes in the MSC secretome.A, The main molecular functions shown by PANTHER for 62 proteins in the MSC secretome identified as “secreted” and as exhibiting increased abundance after IGF-II treatment. B. Enriched protein classes, C. Enriched biological processes. P, probability.
Mentions: Gene ontology, functional enrichment and pathway analysis of the 64 proteins were performed using PANTHER with a significance threshold cut-off of p<0.05 for proteins identified as constituting the IGF-II-regulated MSC secretome. Analysis of enriched molecular functions showed 7 significantly enriched groups, the top being peptidase activity, represented for example by tissue inhibitor of metalloproteinases (TIMP) -1, -2, -3, and MMP-2 (Fig 3A). A total of 12 protein classes were significantly over-represented of which the top three were extracellular matrix proteins, signalling molecules and proteases (Fig 3B). Gene ontology analysis showed 17 significantly over-represented biological processes with cell adhesion, cell matrix adhesion and cell-cell adhesion as the top three (the top 12 are listed in Fig 3C). The only significant over-represented (>5) pathway was the integrin signalling pathway which was represented by 11 proteins on the regulated secretome list (p = 2.29E-08).

Bottom Line: The calcium ionophore, ionomycin, also rapidly increased secretion of TGFβig-h3 while inhibitors of translation (cycloheximide) or secretory protein transport (brefeldin A) had no effect, indicating secretion from preformed secretory vesicles.Inhibitors of the chemerin and IGF receptors specifically reduced the secretory response.Gene ontology analysis of proteins exhibiting regulated secretion indicated functions primarily associated with cell adhesion and in bioassays chemerin increased adhesion of MSCs and adhesion, proliferation and migration of myofibroblasts.

View Article: PubMed Central - PubMed

Affiliation: Department of Cell and Molecular Physiology, Institute of Translational Medicine, University of Liverpool, Crown St, Liverpool, United Kingdom.

ABSTRACT
Mesenchymal stem cells (MSCs) play important roles in tissue repair and cancer progression. Our recent work suggests that some mesenchymal cells, notably myofibroblasts exhibit regulated exocytosis resembling that seen in neuroendocrine cells. We now report that MSCs also exhibit regulated exocytosis. Both a G-protein coupled receptor agonist, chemerin, and a receptor tyrosine kinase stimulant, IGF-II, evoked rapid increases in secretion of a marker protein, TGFβig-h3. The calcium ionophore, ionomycin, also rapidly increased secretion of TGFβig-h3 while inhibitors of translation (cycloheximide) or secretory protein transport (brefeldin A) had no effect, indicating secretion from preformed secretory vesicles. Inhibitors of the chemerin and IGF receptors specifically reduced the secretory response. Confocal microscopy of MSCs loaded with Fluo-4 revealed chemerin and IGF-II triggered intracellular Ca2+ oscillations requiring extracellular calcium. Immunocytochemistry showed co-localisation of TGFβig-h3 and MMP-2 to secretory vesicles, and transmission electron-microscopy showed dense-core secretory vesicles in proximity to the Golgi apparatus. Proteomic studies on the MSC secretome identified 64 proteins including TGFβig-h3 and MMP-2 that exhibited increased secretion in response to IGF-II treatment for 30min and western blot of selected proteins confirmed these data. Gene ontology analysis of proteins exhibiting regulated secretion indicated functions primarily associated with cell adhesion and in bioassays chemerin increased adhesion of MSCs and adhesion, proliferation and migration of myofibroblasts. Thus, MSCs exhibit regulated exocytosis that is compatible with an early role in tissue remodelling.

No MeSH data available.


Related in: MedlinePlus