High-Intensity Interval Training Is Associated With Alterations in Blood Biomarkers Related to Brain Injury.

Blood biomarkers are a useful tool to study concussion. However, their interpretation is complicated by a number of potential biological confounds, including exercise. This is particularly relevant in military and athletic settings where injury commonly occurs during physical exertion.

Lpaatδ/Agpat4 deficiency impairs maximal force contractility in soleus and alters fibre type in extensor digitorum longus muscle.

Lysophosphatidic acid acyltransferase (LPAAT) δ/acylglycerophosphate acyltransferase 4 is a mitochondrial enzyme and one of five homologues that catalyze the acyl-CoA-dependent synthesis of phosphatidic acid (PA) from lysophosphatidic acid. We studied skeletal muscle LPAATδ and found highest levels in soleus, a red oxidative fibre-type that is rich in mitochondria, and lower levels in extensor digitorum longus (EDL) (white glycolytic) and gastrocnemius (mixed fibre-type). Using Lpaatδ-deficient mice, we found no change in soleus or EDL mass, or in treadmill time-to-exhaustion compared to wildtype littermates.

Agpat4/Lpaatδ deficiency highlights the molecular heterogeneity of epididymal and perirenal white adipose depots.

Acylglycerophosphate acyltransferase 4 (AGPAT4)/lysophosphatidic acid acyltransferase delta catalyzes the formation of phosphatidic acid (PA), a precursor of triacyl-glycerol (TAG). We investigated the effect of gene ablation on white adipose tissue (WAT) after finding consistent expression across depots. Epididymal WAT mass was 40% larger in male mice than littermates, but unchanged in perirenal, retroperitoneal, and inguinal WAT and subscapular brown adipose tissue.

Mice Deficient in (δ)/ () Have Impaired Learning and Memory.

We previously characterized LPAATδ/AGPAT4 as a mitochondrial lysophosphatidic acid acyltransferase that regulates brain levels of phosphatidylcholine (PC), phosphatidylethanolamine (PE), and phosphatidylinositol (PI). Here, we report that δ mice display impaired spatial learning and memory compared to wild-type littermates in the Morris water maze and our investigation of potential mechanisms associated with brain phospholipid changes. Marker protein immunoblotting suggested that the relative brain content of neurons, glia, and oligodendrocytes was unchanged.

Acute Fasting Induces Expression of Acylglycerophosphate Acyltransferase (AGPAT) Enzymes in Murine Liver, Heart, and Brain.

During fasting, cells increase uptake of non-esterified fatty acids (NEFA) and esterify excess into phosphatidic acid (PtdOH), the common precursor of both triacylglycerols and phospholipids, using acylglycerophosphate acyltransferases/lysophosphatidic acid acyltransferases (AGPAT/LPAAT). Knowledge of the regulation of AGPAT enzymes is important for understanding fasting adaptations. Total RNA was isolated from liver, heart, and whole brain tissue of C57BL/6J mice fed ad libitum, or fasted for 16 h.