Substance P promotes expansion of human mesenteric preadipocytes through proliferative and antiapoptotic pathways.
White adipose tissue is intimately involved in the regulation of immunity and inflammation. We reported that human mesenteric preadipocytes express the substance P (SP)-mediated neurokinin-1 receptor (NK-1R), which signals proinflammatory responses. Here we tested the hypothesis that SP promotes proliferation and survival of human mesenteric preadipocytes and investigated responsible mechanism(s). Preadipocytes were isolated from mesenteric fat biopsies during gastric bypass surgery. Proliferative and antiapoptotic responses were delineated in 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS), bromodeoxyuridine (BrdU), caspase-3, and TUNEL assays, as well as Western immunoanalysis. SP (10(-7) M) increased MTS and proliferation (BrdU) and time dependently (15-30 min) induced Akt, EGF receptor, IGF receptor, integrin alphaVbeta3, phosphatidylinositol 3-kinase, and PKC-theta phosphorylation. Furthermore, pharmacological antagonism of Akt and PKC-theta activation significantly attenuated SP-induced preadipocyte proliferation. Exposure of preadipocytes to the proapoptotic Fas ligand (FasL, 100 microM) resulted in nuclear DNA fragmentation (TUNEL assay), as well as increased cleaved poly (ADP-ribose) polymerase, cleaved caspase-7, and caspase-3 expression. Cotreatment with SP almost completely abolished these responses in a NK-1R-dependent fashion. SP (10(-7) M) also time dependently stimulated expression 4E binding protein 1 and phosphorylation of p70 S6 kinase, which increased protein translation efficiency. SP increases preadipocyte viability, reduces apoptosis, and stimulates proliferation, possibly via cell cycle upregulation and increased protein translation efficiency. SP-induced proliferative and antiapoptotic pathways in fat depots may contribute to development of the creeping fat and inflammation characteristic of Crohn's disease.
Gross
Kara
K
Gastrointestinal Neuropeptide Center, Division of Gastroenterology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, Massachusetts, USA.
Karagiannides
Iordanes
I
Thomou
Thomas
T
Koon
Hon Wai
HW
Bowe
Collin
C
Kim
Ho
H
Giorgadze
Nino
N
Tchkonia
Tamara
T
Pirtskhalava
Tamara
T
Kirkland
James L
JL
Pothoulakis
Charalabos
C
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D017667:Adipocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D017209:Apoptosis / Q000187:drug effects; D053148:Caspase 3 / Q000378:metabolism; D053179:Caspase 7 / Q000378:metabolism; D002453:Cell Cycle; D018797:Cell Cycle Proteins; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival; D002478:Cells, Cultured; D066246:ErbB Receptors / Q000378:metabolism; D053222:Fas Ligand Protein / Q000378:metabolism; D006801:Humans; D039302:Integrin alphaVbeta3 / Q000378:metabolism; D050152:Intra-Abdominal Fat / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D007527:Isoenzymes / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism; D000074121:Protein Kinase C-theta; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000378:metabolism; D018040:Receptors, Neurokinin-1 / Q000378:metabolism; D038762:Ribosomal Protein S6 Kinases, 70-kDa / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013373:Substance P / Q000378:metabolism*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
D048868:Adaptor Proteins, Signal Transducing; D053148:Caspase 3; D053179:Caspase 7; D018797:Cell Cycle Proteins; D066246:ErbB Receptors; D053222:Fas Ligand Protein; D039302:Integrin alphaVbeta3; D007527:Isoenzymes; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010750:Phosphoproteins; D011065:Poly(ADP-ribose) Polymerases; D011493:Protein Kinase C; D000074121:Protein Kinase C-theta; D047428:Protein Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D017526:Receptor, IGF Type 1; D018040:Receptors, Neurokinin-1; D038762:Ribosomal Protein S6 Kinases, 70-kDa; D013373:Substance P; D014409:Tumor Necrosis Factor-alpha; C087000:EIF4EBP1 protein, human; C512478:EGFR protein, human; C076233:PRKCQ protein, human; C505407:CASP3 protein, human; C505520:CASP7 protein, human