Fig 1.
Glucose-stimulated insulin secretion from human islets treated with palmitate.
Islets were treated with palmitate for two (P2) and seven (P7) days or without it in control conditions (C). Subsequently post culture, insulin secretion during glucose stimulation was assessed by perifusing islets with a buffer containing 2 mM glucose (first 20 minutes) followed by 20 mM glucose (last 20 minutes). Total amount of insulin secreted during glucose stimulation (A) and the kinetic secretory responses (B) are shown. Secretion amount from 6 donors was adjusted to total islet protein amount. Results show means ± SEM as fold control in panel A and ± SD in panel B. ** P<0.005 and *** P<0.0005 vs control.
Fig 2.
Insulin and proinsulin content in human islets treated with palmitate.
Islets were treated for seven days with palmitate (P7). Subsequently, insulin and proinsulin content was measured. Results show means ± SEM as fold control (fold change of control) from 4 donors. * P<0.05 vs control.
Table 1.
Differentially expressed islet proteins after palmitate treatment for 7 days.
Fig 3.
Differentially expressed islet lipids after palmitate treatment for 2 and 7 days.
The PubChem Compound Identification (CID) is indicated in each case. Stearic acid and cholesterol were measured in μg, C16 dihydroceramide and C24:1 sphingomyelin were measured in pmol. *P-value of less than 0.05.
Fig 4.
Insulin action, top scoring pathway for islet proteomics data.
Down-regulated (green), up-regulated (red), unchanged (brown) and not detected (white) proteins when control (C) and P2 islets (A) and C and P7 islets (B) were compared. Each wedge in a node represents one of the six donors, the position of a particular donor’s wedge in a node is consistent throughout the figure.
Fig 5.
Insulin action pathway showing the averages over all six donors at P2 (left half of node) and P7 (right half of node).
Down-regulated (green), up-regulated (red), unchanged (brown) and not detected (white) proteins are shown.
Table 2.
Enriched pathways based on the islet proteomics data set from a single donor.
Table 3.
Pathway ranking scores for islet proteomics data.
Fig 6.
Fatty acid biosynthesis pathway.
Proteins are indicated as circles, lipids as squares. The proteins in the pathway all catalyze multiple steps in the process and are thus shown multiple times. The averages over all six donors at P2 (left half of node) and P7 (right half of node) are shown. Down-regulated proteins/lipids are shown in green, up-regulated in red, unchanged in brown and not detected in white.
Fig 7.
Sphingolipid metabolism pathway.
Proteins are indicated as circles, lipids as squares. For the proteins, only one representative or no representative of each class was detected, and only this protein or no protein, respectively, was then shown. The averages over all six donors at P2 (left half of node) and P7 (right half of node) are represented. Down-regulated proteins/lipids are shown in green, up-regulated in red, unchanged in brown and not detected in white.