Insulin-regulated serine and lipid metabolism drive peripheral neuropathy - Nature.com

To test whether altered systemic substrate utilization of carbohydrates in preference to lipids were driving the changes in adiposity, we placed mice that had consumed each diet for 18 weeks in metabolic cages and quantified the respiratory exchange ratio (RER).

Conversely, PERMANOVA testing of Aitchison distances from robust principal component analysis revealed significant beta-diversity differences between −SG HFD-fed mice and other groups, highlighting the distinct effect of this low-carbohydrate, high-fat, serine and glycine-restricted diet on the faecal microbiome (Extended Data Fig.

Next, to directly investigate how serine deficiency affects hepatic lipogenesis, mice fed the above diets for 18 weeks were administered heavy water (D 2 O) for 18 h, and lipids were extracted for quantification of isotope enrichment, molar abundance, and synthesis 24.

Consistent with results in the −SG HFD diet-induced peripheral neuropathy model, administration of myriocin at six weeks of age prevented progression to thermal hypoalgesia and restored tactile sensation in db/db mice (Extended Data Fig.

C57BL/6J mice fed diets for 18 weeks were injected intraperitoneally with D 2 O (in 0.9% NaCl) at a dose of 0.027 ml per g of body weight with drinking water replaced with 6% D 2 O-enriched solution for a period of ~18 h. In the morning (07:00–10:00 h) tissues were rapidly collected using Wollenberger clamps pre-cooled to the temperature of liquid nitrogen and stored at −80 °C until analysis.

High-resolution LC–MS/MS of polar metabolites Around 10–20 mg of frozen tissue was extracted with 800 µl of −20 °C 5:3:2 acetonitrile: methanol:water solution spike with a known concentration of norvaline as an internal standard using the Precellys Evolution Homogenizer (Bertin Technologies) 68.