Farnesoid X receptor activation protects against renal fibrosis via modulation of β-catenin signaling

Oxidized-LDL aggravates renal injury via tubular cuproptosis

OBJECTIVE

The imbalance of copper homeostasis is closely related to development of kidney injury. We aimed to clarify the mechanism of oxidation of low-density lipoprotein (ox-LDL) aggravated renal injury via tubular copper overload and cuproptosis in lipid-related renal injury.

METHODS

313 patients with kidney disease (KD) confirmed by renal biopsy and 19 healthy participants were enrolled in this study. The copper levels in serum, urine and kidney tissue were assessed and the association between copper and renal function analyzed. We used ox-LDL and a high fat diet (HFD) to develop a pre-clinical renal injury model in HFD fed mice, and measured the levels of copper and cuproptosis biomarkers both in vivo and in vitro, respectively.

RESULTS

Compared to the healthy control group, KD patients showed higher serum and urinary copper levels. Estimated glomerular filtration rate was inversely correlated to serum copper, while 24-hour proteinuria was directly correlated to urinary copper levels. Abnormal deposition of copper salts were observed in kidney tissue of both ORN patients and HFD mice. In vivo and in vitro data showed that lipid may induce mitochondrial dysfunction and promote cuproptosis in tubular epithelial cells, which was related to changes in copper transporter protein ATP7B.

CONCLUSION

ox-LDL can promote copper overload in renal tubular cells by suppressing ATP7B, thereby inducing cuproptosis and promoting lipid-related kidney injury.

Design, synthesis and FXR partial agonistic activity of anthranilic acid derivatives bearing aryloxy moiety as therapeutic agents for metabolic dysfunction-associated steatohepatitis

Farnesoid X receptor (FXR) is considered a promising therapeutic target for the treatment of metabolic dysfunction-associated steatohepatitis (MASH). Increasing evidence suggests that targeting FXR with full agonists may lead to side effects. FXR partial agonists, which moderately activate FXR signaling, are emerging as a feasible approach to mitigate side effects and address MASH. Herein, a series of novel anthranilic acid derivatives bearing aryloxy moiety were designed and synthesized using a hybrid strategy from the previously identified FXR partial agonists DM175 and AIV-25. Particularly, compound 26 exhibited potent FXR partial agonistic activity in a dual-luciferase reporter gene assay with an EC50 value of 0.09 ± 0.02 µM (75.13 % maximum efficacy relative to OCA). In the MASH mice model, compound 26 significantly ameliorated the pathological features of the liver, including steatosis, inflammation, and fibrosis. In addition, compound 26 displayed high selectivity, good oral bioavailability, high liver distribution, as well as an acceptable safety profile. Molecular simulation studies showed that compound 26 fitted well with the binding site of FXR. Collectively, these findings demonstrated that compound 26 might serve as a promising candidate targeting FXR for MASH treatment.

MAFLD as part of systemic metabolic dysregulation

Nonalcoholic fatty liver disease (NAFLD) is one of the most common chronic liver diseases worldwide. In recent years, a new terminology and definition of metabolic dysfunction-associated fatty liver disease (MAFLD) has been proposed. Compared to the NAFLD definition, MAFLD better emphasizes the pathogenic role of metabolic dysfunction in the development and progression of this highly prevalent condition. Metabolic disorders, including overweight/obesity, type 2 diabetes mellitus (T2DM), atherogenic dyslipidemia and hypertension, are often associated with systemic organ dysfunctions, thereby suggesting that multiple organ damage can occur in MAFLD. Substantial epidemiological evidence indicates that MAFLD is not only associated with an increased risk of liver-related complications, but also increases the risk of developing several extra-hepatic diseases, including new-onset T2DM, adverse cardiovascular and renal outcomes, and some common endocrine diseases. We have summarized the current literature on the adverse effect of MAFLD on the development of multiple extrahepatic (cardiometabolic and endocrine) complications and examined the role of different metabolic pathways and organ systems in the progression of MAFLD, thus providing new insights into the role of MAFLD as a multisystem metabolic disorder. Our narrative review aimed to provide insights into potential mechanisms underlying the known associations between MAFLD and extrahepatic diseases, as part of MAFLD as a multisystem disease, in order to help focus areas for future drug development targeting not only liver disease but also the risk of extrahepatic complications.