RESUMO
Tartary buckwheat is used as an ingredient in flour and tea, as well as in traditional Chinese medicine for its antioxidant effects. Here, we found that an ethanol extract of tartary buckwheat (TBE) potently induced autophagy flux in HeLa cells by suppressing mTORC1 activity, as revealed by dephosphorylation of the mTORC1 substrates Ulk1, S6K, and 4EBP, as well as by the nuclear translocation of transcriptional factor EB. In addition to non-selective bulk autophagy, TBE also induced aggrephagy, which is defined as autophagy against aggregated proteins. Quercetin is a flavonol found at high levels in TBE. We showed that quercetin induced both non-selective bulk autophagy and aggrephagy. These effects were also observed in Huh-7 cells derived from hepatocytes. Thus, aggrephagy induction by TBE and quercetin may relieve alcoholic hepatitis, which is closely linked to the accumulation of protein aggregations called Mallory-Denk bodies.
RESUMO
Kampo, a system of traditional Japanese therapy utilizing mixtures of herbal medicine, is widely accepted in the Japanese medical system. Kampo originated from traditional Chinese medicine, and was gradually adopted into a Japanese style. Although its effects on a variety of diseases are appreciated, the underlying mechanisms remain mostly unclear. Using a quantitative tf-LC3 system, we conducted a high-throughput screen of 128 kinds of Kampo to evaluate the effects on autophagy. The results revealed a suppressive effect of Shigyakusan/TJ-35 on autophagic activity. TJ-35 specifically suppressed dephosphorylation of ULK1 and TFEB, among several TORC1 substrates, in response to nutrient deprivation. TFEB was dephosphorylated by calcineurin in a Ca2+ dependent manner. Cytosolic Ca2+ concentration was increased in response to nutrient starvation, and TJ-35 suppressed this increase. Thus, TJ-35 prevents the starvation-induced Ca2+ increase, thereby suppressing induction of autophagy.