Hpx, or hemopexin, is a protein-encoding gene. Hemopexin is an important component in the body, mainly involved in heme-binding and transportation, which plays a crucial role in maintaining iron homeostasis and protecting cells from the toxic effects of free heme [4].

In Caenorhabditis elegans, the Hpx-related gene hpx-2 encodes a heme-peroxidase. Loss-of-function experiments showed that hpx-2 mutant animals had a weaker cuticle structure, increased intestinal colonization of E. faecalis, and decreased survival on E. faecalis when a catalytic residue in the peroxidase domain was disrupted. RNA-seq analysis of the hpx-2 mutant revealed changes in genes related to cuticle structure under non-pathogenic conditions and greater differential regulation of infection-response genes under pathogenic conditions, indicating that HPX-2 contributes to pathogen resistance by generating cuticle material in the hypodermis and pharynx [1].

In a rat model of diarrhea-predominant irritable bowel syndrome (IBS-D), treatment with Xingpi Capsule increased the relative expression level of the metabolite HPX. In vitro experiments showed that HPX can alleviate LPS-induced damage in human colonic epithelial cells by inhibiting MAP3K5 and its downstream pathways, suggesting a role in IBS-D treatment [2].

In Korean patients with systemic lupus erythematosus (SLE), urinary HPX levels were significantly elevated, especially in those with lupus nephritis. Follow-up of biomarker levels showed a decrease correlated with changes in SLEDAI-2k scores, indicating its potential as a non-invasive biomarker for tracking disease activity [3].

In conclusion, Hpx and its related proteins play diverse biological functions. In model organisms like C. elegans, it is involved in pathogen resistance, while in mammalian disease models such as IBS-D rats and SLE patients, it is associated with disease-related processes. The study of Hpx using gene-based models helps to understand its role in various biological processes and diseases, potentially providing new insights for disease treatment and biomarker development.