Spatial transcriptomics maps macrophage-centric inflammatory niches in diabetic kidneys. 2. M1 macrophages drive arginine metabolism dysregulation via suppressed Arg1. 3. Astragaloside IV restores Arg1 expression and reprograms macrophage polarization. 4. Urinary L-Arg/L-Orn ratio achieves perfect diagnostic accuracy. 5. ASIV targets arginine metabolism, offering a microenvironment-guided therapy. This study aimed to elucidate the therapeutic potential and mechanistic basis of Astragaloside IV (ASIV), a natural compound from Astragalus membranaceus , in diabetic nephropathy (DN) by investigating its ability to target spatially dysregulated metabolism within inflammatory kidney microenvironments. DN is characterized by complex inflammatory microenvironments and metabolic dysregulation, yet the spatial architecture and underlying molecular mechanisms remain poorly understood. Here, we employ high-definition spatial transcriptomics coupled with mass spectrometry imaging to decode the spatially organized inflammatory microenvironments in human kidneys. We uncover macrophage-centric inflammatory niches, where M1-polarized macrophages dominate and exhibit suppressed Arg1-mediated arginine metabolism, affecting the localized metabolic dysfunction. Cross-species validation in diabetic mice confirms conserved macrophage heterogeneity and arginine-proline pathway dysregulation, establishing its central role in DN pathogenesis. Integrating urinary proteomics, we identify Arg1 and Fgl2 as mechanistically linked biomarkers, with urinary L-arginine/L-ornithine ratios achieving high diagnostic accuracy. Strikingly, spatial metabolomics reveals compartmentalized arginine disruption, where L-arginine accumulation and ornithine depletion correlate with inflammatory severity. Therapeutically, we demonstrate ASIV restores Arg1 expression, normalizes arginine metabolism, and reprograms macrophage polarization from pro-inflammatory M1 to repair states. The regulation of the self-perpetuating inflammatory loop in diabetic kidneys by ASIV is mechanistically linked to its dual targeting of arginine metabolism and TNF-α signaling. Our study redefines DN as a spatially immune-metabolic disorder, with macrophage-driven arginine dysregulation as a key therapeutic pathway. By bridging spatial multi-omics with urinary biomarkers, we provide a framework for diagnosing and treating DN through microenvironment-guided metabolic dysfunction.
Qiu et al. (Thu,) studied this question.