Dyakonov-Perel-like Orbital and Spin Relaxations in Centrosymmetric Systems.

The Dyakonov-Perel (DP) mechanism of spin relaxation has long been considered irrelevant in centrosymmetric systems since it was developed originally for noncentrosymmetric ones. We investigate whether this conventional understanding extends to the realm of orbital relaxation, which has recently attracted significant attention. Surprisingly, we find that orbital relaxation in centrosymmetric systems exhibits the DP-like behavior in the weak scattering regime. Moreover, the DP-like orbital relaxation can make the spin relaxation in centrosymmetric systems DP-like through the spin-orbit coupling. We also find that the DP-like orbital and spin relaxations are anisotropic even in materials with high crystal symmetry (such as face-centered cubic structure) and may depend on the orbital and spin nature of electron wave functions.

Graphislactone A, a Fungal Antioxidant Metabolite, Reduces Lipogenesis and Protects against Diet-Induced Hepatic Steatosis in Mice.

Graphislactone A (GPA), a secondary metabolite derived from a mycobiont found in the lichens of the genus Graphis, exhibits antioxidant properties. However, the potential biological functions and therapeutic applications of GPA at the cellular and animal levels have not yet been investigated. In the present study, we explored the therapeutic potential of GPA in mitigating non-alcoholic fatty liver disease (NAFLD) and its underlying mechanisms through a series of experiments using various cell lines and animal models. GPA demonstrated antioxidant capacity on a par with that of vitamin C in cultured hepatocytes and reduced the inflammatory response induced by lipopolysaccharide in primary macrophages. However, in animal studies using an NAFLD mouse model, GPA had a milder impact on liver inflammation while markedly attenuating hepatic steatosis. This effect was confirmed in an animal model of early fatty liver disease without inflammation. Mechanistically, GPA inhibited lipogenesis rather than fat oxidation in cultured hepatocytes. Similarly, RNA sequencing data revealed intriguing associations between GPA and the adipogenic pathways during adipocyte differentiation. GPA effectively reduced lipid accumulation and suppressed lipogenic gene expression in AML12 hepatocytes and 3T3-L1 adipocytes. In summary, our study demonstrates the potential application of GPA to protect against hepatic steatosis in vivo and suggests a novel role for GPA as an underlying mechanism in lipogenesis, paving the way for future exploration of its therapeutic potential.