[Letter to the Editor] Protein phosphorylation status is preserved following dual RNA and protein extraction using the Qiagen RNeasy Mini Kit

Delta-6 desaturase (Fads2) deficiency alters triacylglycerol/fatty acid cycling in murine white adipose tissue

The Δ-6 desaturase (D6D) enzyme is not only critical for the synthesis of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from α-linolenic acid (ALA), but recent evidence suggests that it also plays a role in adipocyte lipid metabolism and body weight; however, the mechanisms remain largely unexplored. The goal of this study was to investigate if a D6D deficiency would inhibit triacylglycerol storage and alter lipolytic and lipogenic pathways in mouse white adipose tissue (WAT) depots due to a disruption in EPA and DHA production. Male C57BL/6J D6D knockout (KO) and wild-type (WT) mice were fed either a 7% w/w lard or flax (ALA rich) diet for 21 weeks. Energy expenditure, physical activity, and substrate utilization were measured with metabolic caging. Inguinal and epididymal WAT depots were analyzed for changes in tissue weight, fatty acid composition, adipocyte size, and markers of lipogenesis, lipolysis, and insulin signaling. KO mice had lower body weight, higher serum nonesterified fatty acids, smaller WAT depots, and reduced adipocyte size compared to WT mice without altered food intake, energy expenditure, or physical activity, regardless of the diet. Markers of lipogenesis and lipolysis were more highly expressed in KO mice compared to WT mice in both depots, regardless of the diet. These changes were concomitant with lower basal insulin signaling in WAT. Collectively, a D6D deficiency alters triacylglycerol/fatty acid cycling in WAT by promoting lipolysis and reducing fatty acid re-esterification, which may be partially attributed to a reduction in WAT insulin signaling.

Effect of Cannabidiol (CBD) on Canine Inflammatory Response: An Ex Vivo Study on LPS Stimulated Whole Blood

The use of cannabidiol (CBD) for animal species is an area of growing interest, for example for its anti-inflammatory and immuno-modulating properties, even though all of its biological effects are still not fully understood, especially in veterinary medicine. Therefore, the aim of this study was to investigate the anti-inflammatory and immuno-modulating properties of CBD for the first time directly in canine inflammatory response. We used an ex vivo model of LPS-stimulated whole dog blood. We stimulated the whole blood from healthy dogs with LPS 100 ng/mL for 24 h in the presence or not of CBD 50 and 100 μg/mL. We observed a reduction in IL-6 and TNF-α production from the group treated with CBD, but non-altered IL-10 levels. Moreover, we also observed from the CBD-treated group a reduction in Nf-κB and COX-2 expression. In conclusion, we demonstrated for the first time the anti-inflammatory and immuno-modulating properties of CBD directly in dogs' immune cells, using a canine ex vivo inflammatory model. The results obtained from these studies encourage further studies to better understand the possible therapeutic role of CBD in veterinary medicine.

Safflower (n-6) and flaxseed (n-3) high-fat diets differentially regulate hypothalamic fatty acid profiles, gene expression, and insulin signalling

Polyunsaturated fatty acids (PUFA) have important signalling roles in the hypothalamus, a region of the brain that regulates whole-body energy homeostasis. While evidence suggests that high PUFA intake can impact hypothalamic activity, the underlying molecular mechanisms regulated by essential dietary n-6 and n-3 PUFA (i.e., linoleic acid and α-linolenic acid, respectively) remain poorly described in this brain region. To differentiate the roles of essential dietary PUFA on hypothalamic function, we fed male rats high-fat diets (35% kcal/d) containing either safflower (linoleic acid) or flaxseed (α-linolenic acid) oil for 2 months. Control rats were fed a low-fat (16% kcal/d) diet containing soybean oil. Hypothalamic fatty acids and gene expression were investigated by gas chromatography and microarray, respectively. Safflower-fed rats had higher total n-6 PUFA content due to increases in linoleic acid, arachidonic acid, and osbond acid compared to the other diet groups, while flaxseed-fed rats had higher total n-3 content due to increases in α-linolenic acid, eicosapentaenoic acid, docosapentaenoic acid, and docosahexaenoic acid. Safflower-fed rats showed augmented expression of genes related to hypothalamic insulin signalling compared to controls. This was mirrored by significant increases in phosphorylated AKT^thr308 and AKT^ser473 levels; indicative of increased PI(3)K/AKT pathway activity. These changes were not observed in the hypothalamus of flaxseed-fed rats. Our findings provide new molecular insights into how essential fatty acids influence the hypothalamus and, potentially, whole-body energy homeostasis. This work also provides new knowledge to better understand the impact of essential fatty acids on metabolic and behavioral phenotypes.

Reduced SCD1 activity alters markers of fatty acid reesterification, glyceroneogenesis, and lipolysis in murine white adipose tissue and 3T3-L1 adipocytes

White adipose tissue (WAT) has a critical role in lipid handling. Previous work demonstrated that SCD1 is an important regulator of WAT fatty acid (FA) composition; however, its influence on the various interconnected pathways influencing WAT lipid handling remains unclear. Our objective was to investigate the role of SCD1 on WAT lipid handling using Scd1 knockout (KO) mice and SCD1-inhibited 3T3-L1 adipocytes by measuring gene, protein, and metabolite markers related to FA reesterification, glyceroneogenesis, and lipolysis. Triacylglycerol (TAG) content was higher in inguinal WAT (iWAT) from KO mice compared with wild-type, but significantly lower in epididymal WAT (eWAT). The SCD1 desaturation index was decreased in both WAT depots in KO mice. FA reesterification, as measured with a NEFA:glycerol ratio, was reduced in both WAT depots in KO mice, as well as SCD1-inhibited 3T3-L1 adipocytes. Pck1, Atgl, and Hsl gene expression was reduced in both WAT depots of KO mice, while Pck2 and Pdk4 gene expression showed depot-specific regulation. Pck1, Atgl, and Hsl gene expression was reduced, and phosphoenolpyruvate carboxykinase protein content was ablated, in SCD1-inhibited adipocytes. Our data provide evidence that SCD1 has a broad impact on WAT lipid handling by altering TAG composition in a depot-specific manner, reducing FA reesterification, and regulating markers of lipolysis and glyceroneogenesis.