Fibroblasts from type 1 diabetics exhibit enhanced Ca(2+) mobilization after TNF or fat exposure

• Published in: PloS one 2014, Vol.9 (1), p.e87068-e87068
• Main Authors: Husni, Nicholas R, Jones, 4th, Albert R, Simmons, Amber L, Corkey, Barbara E
• Format: Article
• Language: English
• Subjects: Blotting, Western; Bradykinin - metabolism; Calcium - metabolism; Case-Control Studies; Cells, Cultured; Cytokines - metabolism; Dermis - cytology; Dermis - drug effects; Dermis - metabolism; Diabetes Mellitus, Type 1 - drug therapy; Diabetes Mellitus, Type 1 - metabolism; Diabetes Mellitus, Type 1 - pathology; Endoplasmic Reticulum - drug effects; Endoplasmic Reticulum - metabolism; Enzyme Inhibitors - pharmacology; Fatty Acids, Nonesterified - pharmacology; Fibroblasts - cytology; Fibroblasts - drug effects; Fibroblasts - metabolism; Humans; Interleukin-1 - metabolism; Receptors, Bradykinin - metabolism; Siblings; Signal Transduction; Thapsigargin - pharmacology; Tumor Necrosis Factor-alpha - pharmacology
• ISSN: 1932-6203
• DOI: 10.1371/journal.pone.0087068

The effects of cytokine and fatty acid treatment on signal transduction in dermal fibroblasts from type 1 diabetics and matched controls were compared. Chronic exposure to TNF, accentuated Ca(2+) mobilization in response to bradykinin (BK) in cells from both controls and diabetics; responses were three-fold greater in cells from diabetics than in controls. Similarly, with chronic exposure to IL-1β, BK-induced Ca(2+) mobilization was accentuated in cells from type 1 diabetics compared to the controls. Pretreatment with the protein synthesis inhibitor cycloheximide or the protein kinase C inhibitor calphostin C prior to the addition of TNF completely abrogated the TNF-induced increment in peak bradykinin response. Ca(2+) transients induced by depleting endoplasmic reticulum (ER) Ca(2+) with thapsigargin were also greater in TNF treated fibroblasts than in untreated cells, with greater increases in cells from diabetics. Exposing fibroblasts for 48 hours to 2 mM oleate also increased both the peak bradykinin response and the TNF-induced increment in peak response, which were significantly greater in diabetics than controls. These data indicate that cells from diabetic patients acquire elevated ER Ca(2+) stores in response to both cytokines and free fatty acids,and thus exhibit greater sensitivity to environmental inflammatory stimuli and elevated lipids.