
The authors investigated the mechanism of Aβ(1-40) elimination from the rat brain. The insulin-degrading enzyme (IDE)-selective inhibitor, Ii1, significantly inhibited approximately 70% of Aβ(1-40) elimination across the blood-brain barrier (BBB). Insulin alone also inhibited Aβ elimination; however, the inhibitory effect of the co-administration of insulin and Ii1 was not significantly different from that of Ii1 alone. These findings indicate that IDE is involved in the insulin-sensitive process of Aβ elimination across the BBB. Furthermore, these results suggest that impairment of IDE may contribute to the onset of sporadic Alzheimer’s disease.

The authors examined the effects of metformin on oxidative stress and cellular senescence induced by combined high glucose and UVA exposure in rat keratinocytes, a cellular model relevant to diabetic photoaging. The study showed that hyperglycemia and UVA together increased reactive oxygen species, reduced cell viability, and enhanced senescence-associated markers. Metformin reduced oxidative stress and was associated with attenuation of senescence-related changes, accompanied by improved cell viability. These effects were observed under conditions in which additional activation of AMPK was not evident, suggesting that mechanisms other than enhanced AMPK signaling may contribute to the protective actions of metformin.

The authors found a unique strategy for enhancing antigen-binding affinity of antibody fragments. “Pinpoint” insertion of a single amino acid residue (any of the 20 proteinogenic amino acids) between positions 6 and 7 of the framework region 1 in the heavy-chain variable domain (VH-FR1) generated scFv mutants showing 17−61-fold higher affinity against cortisol, which consequently enabled 22−75-fold more sensitive cortisol ELISAs. Structural modeling of the cortisol−scFv complexes suggested a mechanism by which the insertion altered the paratope conformation to facilitate interaction with cortisol. Thus, the VH-FR1 is promising as a novel “hot region” for affinity maturation of antibodies.

[Highlighted Paper selected by Editor-in-Chief]
The preventive efficacy of empagliflozin
(EMPA) against diabetic neuropathy is largely determined by the daily feeding
cycle. In streptozotocin-induced diabetic mice subjected to time-restricted
feeding (TRF), EMPA produced stronger hypoglycemic and neuropathy-preventive
effects when administered before the daily feeding period, independent of
whether feeding occurred in the light or dark phase. These dosing
time–dependent effects paralleled variations in urinary glucose excretion,
indicating that synchronizing EMPA administration with feeding-related
metabolic rhythms optimizes its protective action against diabetic neuropathy.
