Introduction:
Systemic Lupus Erythematosus (SLE) is a complex autoimmune disease characterized by immune system dysfunction, leading to inflammation and damage in various organs and tissues. Renal involvement known as lupus nephritis is one of the most severe complications occurring in 60% of patients with SLE, significantly impacting patient morbidity and mortality. Understanding the intricate relationship between SLE and renal manifestations is crucial for effective management and improved patient outcomes. Recently, the cell surface urokinase plasminogen activator receptor (uPAR) has emerged as a significant player in the pathogenesis of lupus nephritis. However, the molecular mechanisms through which uPAR influences lupus nephritis remain an active area of investigation. Therefore, we here pursued a transcriptome array-based approach to identify molecular patterns in association with uPAR in lupus nephritis.
Methods:
PLAUR mRNA expression levels (encoding uPAR, reporter ID: 210845_s_at, platform: Affymetrix Human Genome U133 Plus 2.0 Array, altCDF v10) were extracted from microdissected control kidneys (glomerular compartment: n=14) and lupus nephritis (glomerular: n=32, tubulointerstitial: n=32). Pathway analysis was performed for gene enrichment associated with PLAUR mRNA expression with a correlation threshold of ≥0.5 by using reactome (http://reactome.org), pathways with a predefined entities value of p≤0.001 were included. Data was validated in cultured podocytes stressed with Adriamycin, protein expression profiling was performed by mass spectrometry in combination with stable isotope labelling by amino acids in cell culture (SILAC).
Results:
We here identified a predominant glomerular expression of uPAR in lupus nephritis that was increased as compared to healthy controls. While glomerular uPAR expression was predominantly associated with interferon signaling, none of type I or type II interferons were induced. Interestingly, we identified distinct interferon hub genes that were associated with uPAR in lupus nephritis and enriched in stressed podocytes (GBP2: p<0.0001, IFI30: p=0.0006, IFIT1: p<0.0001, IFITM3: p=0.0308). Finally, uPAR and associated interferon hub genes correlated with proteinuria in lupus nephritis.
Conclusions:
The therapeutic implications of targeting uPAR in lupus nephritis are promising, and ongoing research endeavors are aimed at unraveling the complexities of uPAR as a potential diagnostic marker and therapeutic target for this challenging renal pathology. We here expand our current knowledge and link uPAR upregulation in lupus nephritis to distinct interferon hub genes in stressed podocytes.
I have no potential conflict of interest to disclose.
I did not use generative AI and AI-assisted technologies in the writing process.