5β-hydroxycostic acid from Laggera alata ameliorates sepsis-associated acute kidney injury through its anti-inflammatory and anti-ferroptosis effects via NF-κB and MAPK pathways.

ETHNOPHARMACOLOGICAL RELEVANCE

The whole plant of Laggera alata is frequently utilize to remedy inflammatory diseases including nephritis as a traditional Chinese medicine. However, its active ingredients and mechanism of action against sepsis-associated acute kidney injury (SA-AKI) are unknown.

AIM OF THE STUDY

This study aimed to identify active compounds from L. alata that inhibit renal inflammation and ameliorate SA-AKI, and to elucidate their mechanisms of action.

MATERIALS AND METHODS

The chemical constituents were separated from the ethyl acetate layer of L. alata methanol extract by column chromatography over silica gel, medium-pressure liquid chromatography and semipreparative high-performance liquid chromatography. Extensive spectroscopic techniques were applied to determine the chemical structures. The anti-inflammatory efficiency was measured by analyzing the NO production in RAW 264.7 cells. The levels of IL-6, IL-1β, CCL-2 and CCL-5 mRNA were determined by qRT-PCR. Cecal ligation and puncture (CLP) surgery is a frequently applied method to establish the mouse sepsis model. Sepsis was thus induced in mice via CLP. The effect in the treatment of SA-AKI was evaluated by H&E staining and ELISA detection. Western blotting was used to evaluate the protein levels involved in ferroptosis, NF-κB and MAPK signaling pathways.

RESULTS

Twelve compounds were obtained from L.alata including four unreported sesquiterpenoids (1-4). Compound 5 exhibited the most significant inhibitory effect on NO production with the IC value of 6.034 μM and could restrain the mRNA expression of inflammatory factors IL-6, IL-1β, CCL-2 and CCL-5. The in vivo results demonstrated that compound 5 alleviated the renal injury by decreasing the serum IL-6, IL-1β, Cr, and BUN levels, reducing the kidney contents of Cys-C and KIM-1, and regulating the kidney levels of MDA, GSH, ferrous iron, GPX4, FTH1, and SLC7A11. Furthermore, Compound 5 also repressed the NF-κB and MAPK pathways in vitro and in vivo.

CONCLUSIONS

This study revealed that compound 5 could ameliorate SA-AKI through exerting its anti-inflammatory and anti-ferroptosis effects via NF-κB and MAPK pathways. The current research supported the traditional use of L.alata in the treatment of renal diseases.