Protein Kinase C Activity Is Reduced in Epidermal Cells from Energy-Restricted SENCAR Mice ,

Abstract

Female SENCAR mice were pre-fed a control or 40% energy-restricted (ER) diet with energy removed from fat and carbohydrate, or a control, balanced high fat (BHF, with similar energy from fat and carbohydrate), 35% energy restricted from fat (HCR) or 35% energy restricted from carbohydrate (HFR) diet. Epidermal cells were isolated by trypsin digestion for measurement of protein kinase C (PKC) activity, lipid composition or lipid metabolism. Dietary restriction of fat or carbohydrate energy (HFR or HCR group) reduced particulate PKC activity in epidermal cells compared with cells from control mice. The ratio of soluble particulate PKC activity was higher in epidermal cells from mice fed the HCR diet compared with those fed the HFR diet. Diet did not affect soluble PKC activity. Inositol accumulation was measured in the water- or lipid-soluble fractions of prelabeled ([3H]inositol) epidermal cells following a 1-h incubation in media with LiCl. Phosphatidylinositol, inositol biphosphate and inositol triphosphate fractions were more heavily labeled in cells from mice fed the ER diet. Energy restriction did not modify epidermal total lipid or phospholipid composition, but 1,2-diacylglycerol levels were elevated in relation to cell number in epidermal cells from mice fed the ER diet. These data suggest that dietary energy restriction modified PKC activity through a pathway other than alteration in membrane lipid composition or inositol lipid metabolism.

Dietary lipid varying in corn and coconut oil influences protein Kinase C in phorbol ester‐treated mouse skin

“…However, cells from mice prefed the high corn oil diet for 10-13 weeks did not show an enhancement of PKC activity, but higher PKC activity was observed in energy-restricted mice fed a high corn oil diet than in control energy-restricted mice (18,31). In addition, modulation of PKC activity by energy restriction was observed in mice restricted for longer (10-13 wk), but not shorter (6-8 wk), periods of time (18). PKC-a in the particulate fraction of the epidermis of Sencar mice was not affected by prefeeding an energy-restricted diet for 6-12 weeks but was reduced 40% in the epidermis of mice prefed the diet for 13-29 weeks (11).…”

“…Elevated PKC activity was reported in epidermal cells from mice fed a high corn oil diet for six to seven weeks compared with cells from animals fed the control diet (14,30). However, cells from mice prefed the high corn oil diet for 10-13 weeks did not show an enhancement of PKC activity, but higher PKC activity was observed in energy-restricted mice fed a high corn oil diet than in control energy-restricted mice (18,31). In addition, modulation of PKC activity by energy restriction was observed in mice restricted for longer (10-13 wk), but not shorter (6-8 wk), periods of time (18).…”

“…However, in studies in which Sencar mice were prefed for 13 weeks agar-containing control and highfat diets with energy from fat and carbohydrate balanced, particulate PKC activity was lower in mice fed the high-fat diet than in control mice (18). Among Sencar mice fed control, high-corn oil (24.5%), or energy-restricted (60% of control energy) diets for 6-29 weeks, the high corn oil diet did not modify the immunoreactive protein levels of the PKC isoforms detected (11).…”

Lipidomic Profiling of Di- and Tri-Acylglycerol Species in Weight-Controlled Mice

“…We are aware of some discrepancies between our data and previously published literature. Kris et al found that calorie restriction increased total DG in the skin of SENCAR mice [ 21 ]. Our study, however, showed no change in total skin DG in calorie restricted mice and exercised and pair-fed mice when compared to controls ( Fig.…”

“…More recently, studies show that DG may also modulate Rho and Ras proteins [ 19 – 20 ]. Kris et al have shown an increase in epidermal DG following calorie restriction suggesting a connection between DG levels and energy balance [ 21 ].…”