Deciphering the complex mechanisms of action of lead detoxification by the green microalga Chlorella vulgaris

Background Lead (Pb) intoxication necessitates detoxification strategies that are efficacious and devoid of adverse effects characteristic of synthetic chelators. The green microalga Chlorella is of particular interest as it exerts diverse metal-binding properties and is rich in micronutrients that collectively support detoxification with a potentially more favorable safety profile. Hypothesis We hypothesized that employing an experimental model with enhanced Pb 2+ transport capacity by cells transfected with a cDNA encoding the divalent metal transporter 1 (DMT1) and Chlorella dietary supplement could help elucidate the specific mechanisms underlying its detoxification action. Methods To identify the optimal species, the extracts from Chlorella vulgaris ( C. vulgaris ) and Chlorella pyrenoidosa ( C. pyrenoidosa ) supplements were compared in metabolomic profiling by HPLC-HRMS/MS. The DMT1-overexpressing cell model was constructed by assessing the detoxification efficacy of C. vulgaris extract using cell viability and the Trolox equivalent antioxidant capacity assays. Pb 2+ concentration was measured by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). To map the complex mechanisms of action, transcriptomic analyses were performed and analyzed via Ingenuity Pathway Analysis (IPA) and validated by western blotting and fluorescence microscopy. Results Metabolite profiling and antioxidant capacity assay identified the C. vulgaris aqueous extract as superior. It attenuated Pb 2+ -induced cytotoxicity and prone to promote cellular Pb 2+ export in DMT1-transfected cells. Transcriptomics revealed that Pb 2+ exhibited a signature of hepatorenal toxicity, and the aqueous extract rescued the zinc finger protein’s function. Western blot and fluorescence microscopy validated that C. vulgaris water extract may orchestrate a multifaceted defense: rectifying Pb 2+ -induced autophagic flux blockage, alleviating ferroptotic stress, triggering an adaptive metabolic shift via protein lipoylation and a p-STAT3-mediated survival pathway, jointly preserving microtubule integrity. Conclusion These findings advance prior research by first providing a comprehensive detoxification mechanism framework of C. vulgaris , positioning C. vulgaris as a promising, multi-mechanism supplement for mitigating Pb 2+ poisoning.