The liver plays a pivotal role in maintaining euglycemia. Biogenesis and function of mitochondria within hepatocytes are often the first to be damaged in a diabetic population, and restoring its function is recently believed to be a promising strategy on inhibiting the progression of diabetes. Previously, we demonstrated that the gut microbiota metabolite butyrate could reduce hyperglycemia and modulate the metabolism of glycogen in both db/db mice and HepG2 cells. To further explore the mechanism of butyrate in controlling energy metabolism, we investigated its influence and underlying mechanism on the biogenesis and function of mitochondria within high insulin-induced hepatocytes in this study. We found that butyrate significantly modulated the expression of 54 genes participating in mitochondrial energy metabolism by a PCR array kit, both the content of mitochondrial DNA and production of ATP were enhanced, expressions of histone deacetylases 3 and 4 were inhibited, beta-oxidation of fatty acids was increased, and oxidative stress damage was ameliorated at the same time. A mechanism study showed that expression of GPR43 and its downstream protein beta-arrestin2 was increased on butyrate administration and that activation of Akt was inhibited, while the AMPK-PGC-1alpha signaling pathway and expression of p-GSK3 were enhanced. In conclusion, we found in the present study that butyrate could significantly promote biogenesis and function of mitochondria under high insulin circumstances, and the GPR43-β-arrestin2-AMPK-PGC1-alpha signaling pathway contributed to these effects. Our present findings will bring new insight on the pivotal role of metabolites from microbiota on maintaining euglycemia in diabetic population.

Chronic kidney disease (CKD) is a chronic progressive disease that seriously threatens human health. Some patients will continue to progress into the CKD stage 3–5 (also called chronic renal failure), which is mainly manifested by a decline in renal function and multi-system damage. Perilla frutescens (L.) Britton. (Lamiaceae) is one of the most widely used traditional Chinese medicine (TCM) herbs in CKD, especially in CKD stage 3–5. But its active components and mechanisms are still unclear. In this study, we used network pharmacology to analyze the active components of P. frutescens and the main therapeutic targets for intervention in CKD stage 3–5. Then, the key components were selected for enrichment analysis and identified by high performance liquid chromatograph (HPLC). Finally, we verified the critical components through molecular docking, and in vitro experiments. The results show that 19 main active components of P. frutescens were screened, and 108 targets were intersected with CKD stage 3–5. The PPI network was constructed and found that the core nodes AKT1, TP53, IL6, TNF, and MAPK1 may be key therapeutic targets. Enrichment analysis shows that related targets may be involved in regulating various biological functions, and play a therapeutic role in CKD stage 3–5 by regulating apoptosis, T cell receptor, and PI3K-AKT signaling pathways. Molecular docking indicates that the key active components were well docked with its corresponding targets. Five active components were identified and quantified by HPLC. According to the results, luteolin was selected as the critical component for further verification. In vitro experiments have shown that luteolin can effectively alleviate adriamycin (ADR)-induced renal tubular apoptosis and suppress AKT and p53 phosphorylation. The effects of luteolin to reduce apoptosis may be mediated by inhibiting oxidative stress and downregulating the mitogen-activated protein kinase (MAPK) and p53 pathways. In general, we screened and analyzed the possible active components, therapeutic targets and pathways of P. frutescens for treating CKD. Our findings revealed that luteolin can reduce renal tubular epithelial cell apoptosis and may be the critical component of P. frutescens in the treatment of CKD. It provides references and direction for further research.

Introduction: Lactate can influence the fibrotic process by regulating cellular metabolism, inflammatory responses, and cell proliferation, which may be closely related to macrophage function in diseases. Therefore, this research sought to identify biomarkers linked to lactate metabolism and macrophages in renal fibrosis (RF).Methods: Firstly, key modular genes associated with macrophage score and lactate metabolism score were identified by combining single-sample gene set enrichment analysis (ssGSEA) and weighted gene co-expression network analysis. Then, candidate genes were obtained by overlapping them with differentially expressed genes between RF and control groups. Subsequently, candidate genes were incorporated into machine learning algorithms to identify key feature genes associated with RF. Expression analysis was then completed to determine biomarkers for this study. Furthermore, the relationship between biomarkers and RF was elucidated by a series of bioinformatics methods, including enrichment analysis, immunosignature analysis, and molecular regulatory analysis. Finally, we validated these key biomarkers in animal experiments.Results: The ssGSEA results showed significantly higher macrophage score and lower lactate metabolism score in the RF samples compared to control samples. Next, AGR3, CD74, and SYT11 were identified as biomarkers for this study because they had consistent expression trends in GSE76882 and GSE135327 datasets and were significantly different between RF and control samples. Moreover, receiver operating characteristic curves showed their excellent accuracy in predicting the occurrence of RF. Subsequent enrichment analysis revealed that three biomarkers were collectively enriched to 50 signaling pathways, including “Toll-like receptor signaling pathway”, “oxidative phosphorylation”, and “P53 signaling pathway”. Notably, CD74 showed a significant positive correlation with macrophages. In lncRNA-miRNA-mRNA network, multiple relationship pairs could be found, e.g., hsa-miR-548x-3p and hsa-miR-548aj-3p were regulators of AGR3, as well as multiple lncRNAs (PCAT6, POLR2J4, SMIM25) could co-regulate CD74 through hsa-miR-4731-5p. Animal experiments also confirmed that the expression of key biomarkers were significantly elevated in the RF rat/mice model. Moreover, the localization and expression of these biomarkers were related to infiltrating inflammatory cells in the kidney tissue.Conclusion: In this study, we found that AGR3, CD74, and SYT11 were biomarkers associated with lactate metabolism and macrophages in RF, providing valuable insights for further RF research.