Scharfenberg, S. | Search bioRxiv

bioRxiv2026

Lactate-dependent metabolic rewiring is associated with CD163+ macrophage polarization in human pyelonephritis

Chronic pyelonephritis is characterized by persistent bacterial infection of the kidney and a dysregulated immune response that promotes disease progression. Macrophages are central regulators of antibacterial immunity in the urinary tract. However, the mechanisms underlying their functional reprogramming in chronic infection remain poorly understood. Here, we identify lactate as a key metabolic determinant of macrophage polarization in human pyelonephritis. Proteomic analysis of human kidney tissue revealed extensive metabolic remodelling, including upregulation of enzymes involved in glycolysis. Consistent with this, lactate levels were significantly elevated in urine and plasma of pyelonephritis patients. Concomitantly, we observed a pronounced accumulation of CD163 macrophages in infected kidneys, representing a distinct macrophage subset with immunomodulatory function. Correlation-based network analysis revealed a strong association between CD163 and lactate dehydrogenase A, supporting a functional association between lactate metabolism and macrophage polarization. Mechanistically, exposure of murine bone marrow-derived macrophages to lactate induced intracellular protein lactylation and promoted polarization toward a CD163 phenotype, defining a metabolically imprinted macrophage state distinct from classical activation paradigms. Proteomic profiling demonstrated extensive remodelling of macrophage protein expression in response to lactate with significant alteration of mediators of phagocytosis, Toll-like receptor signalling, and interferon response. Together, these findings identify lactate as a potent metabolic driver of macrophage reprogramming and establish a foundation for investigating lactylation-dependent immune dysfunction in chronic pyelonephritis.

immunology↗

bioRxiv2025

Redirecting resistance evolution in BRAFV600 melanoma by inhibition of the peroxiredoxin-thioredoxin system

Drug-tolerant persister cells (DTPs) exhibit remarkable cell state heterogeneity and phenotypic evolvability. However, the central question of how DTPs epigenetically coordinate their metabolic flexibility to adapt early to therapeutic stress remains unanswered. We have recently shown that the histone demethylase KDM5B, which is intrinsically expressed in differentiated melanoma DTPs, reprograms the metabolic cell landscape. However, the exact mechanism by which KDM5B affects underlying metabolic enzymes, and whether this reveals new druggable vulnerabilities, remain unknown. By transcriptional and epigenetic profiling of BRAFV600 melanoma cells following KDM5B gene silencing, we discovered a direct molecular axis between the epigenetic regulator KDM5B and the PRDX/TXN ROS detoxification system. This metabolic axis is regulated independently of KDM5Bs demethylase activity. Furthermore, RNAi approaches and the pharmacological inhibition of the PRDX/TXN system led to ROS-induced cell death in differentiated melanoma DTPs and a delay of resistance development to MAPK inhibition. This process was independent of lipid-ROS-driven ferroptosis. Additionally, single-cell transcriptome analyses from pre-clinical melanoma models under continuous MAPK inhibitory treatment demonstrated altered cellular differentiation dynamics, with a reduction in the early evolution into the mesenchymal DTP state under concomitant PRDX inhibition. Interestingly, the degree of melanoma cell state differentiation at the onset of treatment was a major determinant for the transition towards the neural crest-like DTP state. Our study identified a high degree of epigenetic-metabolic connectivity and flexibility within the melanoma DTP pool and urges caution with single redox pathway-targeted strategies for tumor elimination in the future. Prospectively, our results point towards a new resistance targeting strategy for BRAFV600 melanoma patients based on pharmacological re-direction of the evolution of melanoma cell states already at therapy onset. HighlightsO_LITranscriptional and epigenetic profiling identified KDM5B as a regulator of the PRDX/TXN-ROS detoxification system C_LIO_LIPRDX inhibition increases the vulnerability of KDM5Bhigh DTPs to ROS, independent of ferroptosis C_LIO_LIPRDX inhibition delays resistance to MAPK inhibition in BRAFV600 melanoma cells C_LIO_LILongitudinal single-cell transcriptome analysis reveals that PRDX inhibition re-directs early DTP evolution C_LIO_LIPRDX/TXN gene expression is predictive for melanoma patient survival C_LI

cancer biology↗