Urinary MMP-1 Identified as Potential Biomarker for Calcium Oxalate Kidney Stone Disease
核心洞察
Transcriptomic analysis of PBMCs from CaOx kidney stone patients identified 1,063 differentially expressed genes enriched in inflammation, oxidative stress, and ECM-receptor interaction pathways.
Olink proteomics of urine samples revealed eight differentially expressed inflammation-related proteins, with MMP-1 (搜索) showing the most significant upregulation in kidney stone patients.
MMP-1 (搜索) demonstrated diagnostic potential with an AUC of 0.6786 and was ranked top by random forest analysis for distinguishing kidney stone disease (搜索) from healthy controls.
A case-control study from researchers at the Second Affiliated Hospital of Zhengzhou University (搜索) has identified urinary matrix metalloproteinase-1 (MMP-1 (搜索)) as a potential biomarker for calcium oxalate (搜索) (CaOx) kidney stone disease (搜索), while also mapping the transcriptomic landscape of peripheral blood mononuclear cells (PBMCs) in affected patients.
The study enrolled 14 patients diagnosed with CaOx kidney stones and 12 healthy controls, all male, with no significant differences in age or body mass index between groups. Kidney stone composition was confirmed by infrared spectroscopy, with all stones exclusively composed of CaOx — nine pure calcium oxalate (搜索) monohydrate (COM) stones and five mixed COM/calcium oxalate dihydrate (COD) stones.
Transcriptomic Dysregulation in Kidney Stone Disease (搜索)
RNA sequencing of PBMCs identified 58,735 genes, of which 1,063 were significantly altered — 278 upregulated and 785 downregulated — using thresholds of |log2(fold change)| > 1 and adjusted P < 0.05. Principal component analysis demonstrated clear segregation between kidney stone disease (搜索) and healthy control samples.
Gene Ontology enrichment analysis revealed that the most significantly upregulated biological process was the production of molecular mediator of immune response, alongside activation of immune receptor activity. Notably, positive regulation of cytosolic calcium ion concentration was significantly upregulated. KEGG enrichment analysis showed that the most differentially expressed genes were enriched in extracellular matrix (ECM)-receptor interaction, with additional dysregulation observed in JAK-STAT, HIF-1, and Wnt signaling pathways, as well as necroptosis, mitophagy, and autophagy.
Inflammation and Oxidative Stress Pathways
Gene set enrichment analysis (GSEA) focusing on inflammation-related biological processes identified four prominent gene abundance sets: inflammatory response, regulation of inflammatory response, cytokine production involved in inflammatory response, and production of molecular mediator involved in inflammatory response. Core upregulated genes included TLR4, IL-4, CCR2, IL-18, and MyD88.
Oxidative stress pathways were also significantly dysregulated. Lead genes involved in oxidative stress response — CYBB, CAT, SP1, NFIX, NFKB1, MGST1, TXNRD1, and MAPK14 — were all upregulated in the kidney stone disease (搜索) group. Similarly, genes associated with regulation of cellular responses to oxidative stress, including PINK1, ALOX5, MAPKAP1, ABCD1, CD36, OXR1, and NCOA7, were also upregulated.
Urinary Proteomics and MMP-1 (搜索) as a Biomarker
Using Olink Inflammation Panels, the researchers simultaneously measured 92 inflammation-related proteins in urine supernatants. Eight proteins were significantly different (P < 0.05) between groups, with five upregulated and three downregulated. KEGG enrichment analysis indicated dysregulation of MAPK, NF-kappa B, and PI3K-Akt signaling pathways.
Among the differentially expressed proteins, MMP-1 (搜索) was the most significantly upregulated in urine from the kidney stone disease (搜索) group. Random forest feature selection identified MMP-1 as the top-ranked protein for distinguishing kidney stone disease, with the highest mean decrease accuracy of 8. Receiver operating characteristic analysis showed MMP-1 had an area under the curve (AUC) of 0.6786 for diagnosing CaOx kidney stone disease.
The researchers note that MMP-1 (搜索) expression can be induced by oxidative stress, ROS accumulation, and upregulation of MCP-1 binding to CCR2 during inflammatory responses. Upregulation of MMP-1 could directly break down the epithelial barrier by hydrolyzing epithelial cell junction proteins, permitting leukocyte influx into sites of inflammation.
Additional Urinary Protein Alterations
Beyond MMP-1 (搜索), the study identified several other significantly altered urinary proteins. Fibroblast growth factor 5 (FGF-5), programmed death-ligand 1 (PD-L1), CD40, and artemin (ARTN) were significantly upregulated. Conversely, urokinase-type plasminogen activator (uPA), interleukin-24 (IL-24), and vascular endothelial growth factor A (VEGFA) were significantly reduced. Correlation analysis showed that MMP-1 and IL-24 exhibited the strongest negative correlation among the differentially expressed proteins.
Limitations and Future Directions
The authors acknowledge several limitations, including the relatively small sample size for both transcriptomic and proteomic analyses, and the lack of experimental validation. Future studies with larger sample sizes will be needed to enhance the reliability and generalizability of these findings.
The RNA-seq data have been deposited at NCBI GEO under accession number GSE 318167. The study was approved by the Medical Ethics Committee of the Second Affiliated Hospital of Zhengzhou University (搜索) (approval number KY2024087) and funded by the Science Research Start-up Fund for Doctor of The Second Affiliated Hospital of Zhengzhou University.