Current Advances in the Regulatory Effects of Bioactive Compounds from Dietary Resources on Nonalcoholic Fatty Liver Disease: Role of Autophagy

Ganoderma lucidum Spore Powder Alleviates Metabolic-Associated Fatty Liver Disease by Improving Lipid Accumulation and Oxidative Stress via Autophagy

Lipid accumulation and oxidative stress, which could be improved by autophagy, are the "hits" of metabolic-associated fatty liver disease (MAFLD). Ganoderma lucidum spore powder (GLSP) has the effect of improving liver function. However, there are few reports about its effects on and mechanisms impacting MAFLD alleviation. This study investigated the effect of GLSP on hepatic lipid accumulation and oxidative stress and explored the role that autophagy played in this effect. The results showed that GLSP effectively reduced lipid accumulation and activated autophagy in the livers of mice with high-fat-diet-induced disease and palmitic acid-induced hepatocytes. GLSP reduced the lipid accumulation by reducing lipogenesis and promoting lipid oxidation in HepG2 cells. It decreased the production of ROS, increased the activity of SOD and CAT, and improved the mitochondrial membrane potential via the Keap1/Nrf2 pathway. The alleviating effects of GLSP on the lipid accumulation and oxidative stress was reversed by 3-methyladenine (3-MA), an autophagy inhibitor. GLSP activated autophagy via the AMPK pathway in HepG2 cells. In conclusion, GLSP could attenuate MAFLD by the improvement of lipid accumulation and oxidative stress via autophagy. This paper is the first to report the improvement of MAFLD through autophagy promotion. It will shed novel light on the discovery of therapeutic strategies targeting autophagy for MAFLD.

Bibliometric analysis of autophagy in NAFLD from 2004 to 2023

BACKGROUND

Autophagy is a cellular process in which damaged organelles or unnecessary proteins are encapsulated into double-membrane structures and transported to lysosomes for degradation. Autophagy plays a crucial role in various liver diseases, including nonalcoholic fatty liver disease. This study aims to elucidate the role of autophagy in nonalcoholic fatty liver disease through bibliometric analysis.

METHODS

Literature was retrieved from Web of Science CoreCollection database, and the search time was from January 01, 2004 to December 31, 2023. Data retrieval was performed using the Bibliometrix package in R software. VOSviewer and CiteSpace were utilized to visualize the research hotspots and trends related to the effect of autophagy on nonalcoholic fatty liver disease.

RESULTS

A total of 966 papers were obtained, published in 343 journals from 1385 institutions across 57 countries. The journals with the most publications were the "International Journal of Molecular Sciences" and "Scientific Reports." China had the highest number of published papers. The most productive authors were Yen Paul M and Jung Tae Woo, while Singh R was the most frequently co-cited author. Emerging research hotspots were associated with keywords such as insulin resistance, ferroptosis, endoplasmic reticulum stress, and mitochondrial function.

CONCLUSION

Research on autophagy in nonalcoholic fatty liver disease is still in its early stages, with a growing body of literature. This study is the first to provide a comprehensive bibliometric analysis, synthesizing research trends and advancements. It identifies current development trends, global cooperation models, foundational knowledge, research hotspots, and emerging frontiers in the field.

New sesquiterpenes and viridin derivatives from Penicillium sp. Ameliorates NAFLD by regulating the PINK1/Parkin mitophagy pathway

Fungi from the plant rhizosphere microbiome are considered an important source of bioactive novel natural compounds. In this study, three new sesquiterpenes, penisterpenoids A-C (1-3), and three new viridin derivatives, peniviridiols A-C (4-6), along with twenty one known compounds (7-27), were isolated from the rhizosphere fungus Penicillium sp. SMU0102 of medicinal plant Bupleurum chinense DC. Their structures were elucidated by extensive spectroscopic analysis. The absolute configurations of compounds 1-6 were determined by experimental and calculated ECD spectra, DP4 + probability analysis, modified Mosher's method, and X-ray crystallography. All new compounds were screened for their cytotoxic and lipid-lowering activities in vitro. Among them, compound 1 (20 μM) remarkably alleviated lipid accumulation both in FFA-induced LO2 cells and TAA-induced zebrafish NAFLD models. Furthermore, compound 1 enhanced ATP production and mitochondrial membrane potential (MMP), suppressed reactive oxygen species (ROS) formation, restored mitochondrial structure, and induced autophagosome formation. Moreover, compound 1 significantly upregulated the expression of representative proteins for the mitochondrial homeostasis, including OPA1, DRP1, MFF, and Fis1, as well as mitophagy representative proteins PINK1, Parkin, and P62. Further mechanistic investigations indicated that compound 1 primarily alleviated lipid accumulation through selective activation of the PINK1/Parkin mitophagy signaling pathway.

Effects of intermittent cold stimulation on growth performance, meat quality, antioxidant capacity and liver lipid metabolism in broiler chickens

Intermittent cold stimulation (ICS) enhances broilers' resistance to cold stress. Nonetheless, further research is needed to investigate the underlying mechanisms that enhance cold stress resistance. A total of 160 one-day-old male Ross 308 broilers were randomly divided into 2 groups (CC and CS5), with the CC group managing temperature according to the standard for broiler growth stages, while the CS5 group were subjected to cold stimulation at a temperature 3℃ lower than the CC group for 5 h, every 2 d from 15 to 35 d. Sampling was conducted at 36 d (36D), 50 d (50D) and after acute cold stress for 24 h (Y24). First, we examined the effects of ICS on broiler growth performance, meat quality, antioxidant capacity, and lipid metabolism. The results demonstrated that ICS enhanced the performance of broilers to a certain degree. Specifically, the average weight gain in the CS5 group was significantly higher than that of the CC group, and the feed conversion ratio significantly decreased compared to CC at 4 W and 6 W (P ≤ 0.05). Compared with the CC group, cold stimulation significantly reduced drip loss, shearing force, and yellowness (a* value) of chicken meat, while significantly increased redness (b* value) (P ≤ 0.05). At Y24, the levels of T-AOC and GSH-PX in the serum of the CS5 group were significantly higher than those of the CC group, while the level of MDA was significantly lower (P ≤ 0.05). The content of TG, FFA, and VLDL in the serum of the CS5 group was significantly elevated, whereas the level of TC and HDL was significantly lower (P ≤ 0.05). In addition, we further explored whether AMPK-mTOR pathway is involved in the regulation of changes in lipid metabolism and the possible regulatory mechanisms downstream of the signaling pathway. The results showed that ICS significantly upregulated the expression levels of AMPK mRNA and protein in the liver of the CS5 group at 36D and Y24, while significantly down-regulating mTOR (P ≤ 0.05). Compared with the CC group, ICS significantly down-regulated the mRNA expression levels of lipid synthesis and endoplasmic reticulum stress-related genes (SREBP1c, FAS, SCD, ACC, GRP78 and PERK) at 36D and Y24, while significantly up-regulating the mRNA expression levels of lipid decomposition and autophagy-related genes (PPAR and LC3) (P ≤ 0.05). In addition, at Y24, the protein expression levels of endoplasmic reticulum stress-related genes (GRP78) in the CS5 group were significantly lower, while autophagy-related genes (LC3 and ATG7) were significantly higher (P ≤ 0.05). ICS can affect meat quality and lipid metabolism in broilers, and when broilers are subjected to acute cold stress, broilers trained with cold stimulation have stronger lipid metabolism capacity.