Williams, Kristof

Abstract Background Lupus nephritis remains a major cause of chronic kidney disease and kidney failure in systemic lupus erythematosus. Glucocorticoids are central to treatment but are limited by systemic toxicity. We evaluated whether a previously characterized collagen IV α3-targeted liposomal nanoparticle formulation carrying low-dose prednisolone could attenuate established lupus nephritis in MRL/lpr mice. Methods Female MRL/lpr mice with disease present at treatment initiation and C57BL/6J control mice received saline or collagen IV α3-targeted prednisolone-loaded nanoparticles (Col4-α3-Pred-NPs). Renal outcomes were assessed by longitudinal proteinuria, glomerular filtration rate (GFR), survival, kidney histopathology, renal IgG and C3d deposition, dUTP/TUNEL-associated injury staining, and renal cytokine/chemokine profiling. Body weight, food and water intake, and blood glucose were monitored as measures of general condition and preliminary tolerability. Results Col4-α3-Pred-NPs improved survival in MRL/lpr mice, reduced cumulative proteinuria burden, and attenuated terminal GFR decline compared with saline-treated MRL/lpr controls. Treatment reduced glomerular and tubulointerstitial injury, lowered composite EGTI histopathology scores, decreased terminal kidney enlargement, reduced glomerular IgG deposition and renal dUTP-positive injury signals, and reduced renal signals for IL-28A/B, IL-7, PD-ECGF, IL-11, CCL6/C10, and IL-15. C3d deposition was not significantly altered. Nanoparticle treatment was not associated with sustained treatment-related increases in blood glucose or body-weight loss during the measured study period. Conclusions Collagen IV α3-targeted liposomal delivery of low-dose prednisolone attenuated established lupus nephritis in MRL/lpr mice and improved renal structural, functional, inflammatory, and survival outcomes. These findings support further evaluation of glomerulus-targeted nanotherapy as a potential strategy to improve the precision and therapeutic index of glucocorticoid treatment in lupus nephritis.

Abstract Lupus nephritis (LN) requires long-term immunosuppressive therapy, which is often associated with severe systemic side effects. Therefore, new therapeutic strategies that maintain high efficacy while minimizing adverse effects are essential. Although nanomedicine has advanced systemic and kidney-targeted drug delivery, a reliable method for glomerulus-specific delivery is lacking. Collagen IV (Col4)-alpha 3, located in the glomerular basement membrane at the blood–tissue interface through fenestrated capillary endothelium, represents an ideal target for glomeruli delivery. Herein, we developed a novel liposomal nanoparticle conjugated with a Col4-alpha 3-binding peptide (Col4-α3-NPs) for selective glomerular targeting. Prednisolone-loaded Col4-α3-NPs were administered to lupus-prone mice twice weekly for 8 weeks. Kidney injury and function were evaluated biweekly, and renal immune cell populations were analyzed by flow cytometry at study completion. The results show that rhodamine-labeled NPs predominantly accumulate in kidney glomeruli 48 h after intravenous injection. The Col4-NP system demonstrated stable and prolonged release of the encapsulated drug for over 48 h. Lupus-prone mice treated with prednisolone-loaded Col4-NPs showed significantly improved renal function and histology, including a 30% increase in glomerular filtration rate, a 56% reduction in proteinuria, and decreased IgG deposition and fibrosis. Notably, treatment also enhanced renal regulatory T cell populations. These findings suggest that glomerulus-targeted Col4-α3-NPs hold significant translational promise. This platform may offer an effective, site-specific treatment for LN while minimizing systemic side effects and could be adapted for other glomerular diseases requiring targeted therapy.

ABSTRACT Lupus nephritis requires long-term immunosuppressive therapy, which is often associated with severe systemic side effects. Therefore, new therapeutic strategies that maintain high efficacy while minimizing adverse effects is essential. Although nanomedicine has advanced systemic and kidney-targeted drug delivery, a reliable method for glomerulus-specific delivery is lacking. Collagen IV (Col4)-alpha 3, located in the glomerular basement membrane (GBM) at the blood–tissue interface through fenestrated capillary endothelium, represents an ideal target for glomeruli delivery. Herein, we developed a novel liposomal nanoparticle conjugated with a Col4-alpha 3 binding peptide (Col4-α3-NPs) for selective glomerular targeting. Prednisolone-loaded Col4-α3-NPs were administered to lupus-prone mice twice weekly for 8 weeks. Kidney injury and function were evaluated biweekly, and renal immune cell populations were analyzed by flow cytometry at study completion. The results show that rhodamine-labeled NPs predominantly accumulate in kidney glomeruli 48 hours after intravenous injection. The Col4-NP system demonstrated stable and prolonged release of the encapsulated drug for over 48 hours. Lupus-prone mice treated with prednisolone-loaded Col4-NPs showed significantly improved renal function and histology, including a 30% increase in glomerular filtration rate (GFR), a 56% reduction in proteinuria, and decreased IgG deposition and fibrosis. Notably, treatment also enhanced renal regulatory T cell (Treg) populations. These findings suggest that glomerulus-targeted Col4-α3-NPs hold significant translational promise. This platform may offer an effective, site-specific treatment for lupus nephritis while minimizing systemic side effects and could be adapted for other glomerular diseases requiring targeted therapy.

Abstract Background Acute kidney injury (AKI) frequently causes remote organ injury including hepatic steatosis, yet whether lipid accumulation reflects increased synthesis or impaired clearance has not been resolved. Methods We used a murine ischemia-reperfusion AKI model. Unbiased liver proteomics was performed at 24 hours after reperfusion, and dysregulated pathways were identified by Gene Set Enrichment Analysis. Results were validated by Western blotting, qPCR, and immunohistochemistry. These findings were complemented by retrospective analysis of two ICU databases (MIMIC-IV and eICU-CRD). Results AKI significantly increased serum ALT and AST and induced hepatic lipid accumulation. Proteomic analysis revealed that key lipogenic enzymes (Scd1, Fasn, Acly, Acaca) were uniformly suppressed rather than upregulated. Proteins essential for VLDL assembly (ApoB, MTTP, ApoE) were significantly downregulated. Plasma triglycerides were decreased while liver triglycerides were increased, consistent with impaired hepatic lipid export. As in renal tubular cells, AKI also disrupted ER protein folding homeostasis in the liver, triggering ER stress. This was evidenced by upregulated levels of the ER chaperone GRP78, increased XBP1 splicing indicative of UPR activation, and elevated expression of the ER stress-induced pro-apoptotic transcription factor CHOP, suggesting that prolonged ER stress may also promote hepatocyte cell death. TLR4/MyD88 signaling was activated, yet inflammatory cytokines were paradoxically reduced, accompanied by Kupffer cell depletion (decreased F4/80) and monocyte infiltration (increased CD68). In 6,996 propensity-matched ICU patients (MIMIC-IV), AKI independently increased the risk of clinically significant liver injury 4-fold (adjusted OR = 4.41). Analysis of 22,727 patients across 208 hospitals (eICU-CRD) identified a lipid dissociation pattern: elevated triglycerides alongside decreased total cholesterol, HDL, and LDL, with dose-dependent scaling across KDIGO stages. Conclusions These data support ER stress-mediated impairment of VLDL export as a primary driver of AKI-induced hepatic steatosis. Clinical validation across two independent ICU databases identifies a dual metabolic insult: enhanced peripheral lipid delivery compounds impaired hepatic export, amplifying hepatic lipid retention. ER stress and lipid export machinery represent potential therapeutic targets for AKI-associated liver injury.

Abstract Acute kidney injury (AKI) causes rapid loss of renal function with high morbidity and mortality. Our previous research showed that neuronal nitric oxide synthase (NOS1) mediates nitric oxide-dependent dilation of the afferent arteriole, inhibiting tubuloglomerular feedback (TGF), which critically regulates single nephron glomerular filtration rate (GFR). This mechanism could affect how vulnerable the organ is to ischemic injury, but this has not been directly tested. In the present study, we generated inducible macula densa (MD)-specific NOS1 knockout mice (NKCC2-Cre-NOS1 flox/flox) using a new inducible NKCC2-Cre line crossed with NOS1 flox mice. AKI was induced by 18-min bilateral renal pedicle clamping at 37°C, followed by 48-h reperfusion. Kidney injury was assessed by measuring GFR, plasma creatinine, histology, cytokines, apoptosis, fibrotic factors, and proteomics. Complete NOS1 deletion in MD cells was confirmed through NKCC2/NOS1 immunofluorescence. MD NOS1 deletion enhanced the TGF response, which was further amplified following AKI compared with control (Cre −/−). Following AKI, compared with controls (Cre −/−), NOS1 knockouts showed a significantly lower GFR (236 ± 66 to 24 ± 22 μl/min) and higher plasma creatinine levels, alongside more severe tubular damage evidenced by H&E staining. Cytokine array analysis showed chemokines such as MCP-1 and CXCL1 and macrophage marker CD68 were significantly increased; Western blot analysis showed cleaved caspase-3 levels were significantly increased, indicating enhanced apoptosis. Additionally, fibrosis markers TIMP-1, collagen-3, and α-SMA were significantly up-regulated at both mRNA and protein levels. We further observed increased hypoxia marker hypoxia-inducible factor-1α in MD-specific NOS1 knockout mice (Cre +/−). Global label-free proteomic profiling with targeted validation identified genotype-dependent responses involving haptoglobin, Tacstd2, and Cyp20a1, linking NOS1 deficiency to exaggerated inflammatory, fibrotic, and metabolic pathways. These findings highlight a novel role of MD NOS1 and TGF in AKI pathophysiology, suggesting NOS1 targeting as a therapeutic strategy. Haptoglobin was identified as a downstream plasma signal of NOS1-dependent AKI responses, indicating potential translational value.