Landscape of peripheral immunity in patients with upper urinary tract urolithiasis and the underlying correlations with renal function.

INTRODUCTION: Inflammatory and immunological responses are reported involved in the pathogenesis and progression of obstructive nephropathy (ON). This study was designed to investigate the characteristics of peripheral immunity in patients with upper urinary tract urolithiasis and analyze the underlying associations with renal function. METHODS: Patients with unilateral upper urinary tract urolithiasis meeting the operation indications were prospectively enrolled. Preoperative circulating immune cells and inflammatory cytokines were detected in our clinical laboratory, and the indicators of renal function and calculi related parameters were particularly recorded. Patients were sectionalized into subgroups on the basis of the lesion of calculi. Characteristics of peripheral immunity in each subgroup were investigated by statistical approaches, and the underlying correlations with the degree of hydronephrosis (HN) and renal function were discussed in corresponding group. RESULTS: Patients with ureteral calculi presented severer HN compared with renal calculi, especial middle ureteral calculi, acting as the chief culprit of ON, exhibiting the highest serum creatine and blood urea nitrogen, most impaired estimated glomerular filtration rate, and severest HN. In addition, serum interleukin-8 (IL-8) and IL-6 were demonstrated presenting statistical differences between ureteral calculi and renal calculi patients, exhibiting underlying values in comprehending ON. However, circulating immune cells were demonstrated no obvious differences among groups. CONCLUSIONS: Circulating inflammatory cytokines, referred in particular to serum IL-8 and IL-6 were partially associated with kidney injury in patients with upper urinary tract urolithiasis. But the specific influences and mechanisms between them needed to be investigated furthermore.

Lipidomic study of kidney in a mouse model with urine flow obstruction.

Obstructed urine flow is known to cause structural and functional kidney damage leading to renal fibrosis. However, limited information is available on the change in kidney lipids during urinary tract obstruction. In this study, we investigated the change in lipidome in a mouse model with unilateral ureteral obstruction (UUO). The establishment of the UUO model was confirmed by histopathological examination using transmission electron microscopy. Untargeted liquid chromatography/mass spectrometry was carried out over a time course of 4 and 7 days. Compared to the sham control, the UUO kidney at 7 days showed dilatation of the renal tubule with loss of brush borders and thickening of the capillary endothelium. In the kidney lipidomes obtained from the UUO 7 days group compared to the control, a significant decrease of ceramide, sphingomyelin, phosphatidylcholine, lysophospholipids, and phosphatidylethanolamine was observed, whereas cholesteryl esters, free fatty acids, phosphatidylglycerol, and cardiolipins were significantly increased. The present study revealed the disturbed lipid metabolism in the UUO model, which may provide a clue to potential lipid pathways and therapeutic targets for the early stage of renal fibrosis.

Sorafenib and edaravone protect against renal fibrosis induced by unilateral ureteral obstruction via inhibition of oxidative stress, inflammation, and RIPK-3/MLKL pathway.

Renal fibrosis is the common endpoint of nearly all chronic and progressive nephropathies. Cell death and sterile inflammation are the main characteristics of renal fibrosis, which can lead to end-stage renal failure. The inflammatory reaction triggered by tissue damage is strongly related to necroptosis, a type of caspase-independent, regulated cell death. Using an animal model of unilateral ureteral obstruction (UUO), the anti-fibrotic effects of sorafenib (SOF), a multi-kinase inhibitor, and edaravone (EDV), a potent antioxidant and free radical scavenger, were examined in rats with obstructive nephropathy. Experimentally, animals were divided randomly into five groups: sham; UUO; UUO + SOF (5 mg/kg/day, P.O.); UUO + EDV (20 mg/kg/day, P.O.); and UUO + SOF + EDV groups. The kidney function biomarkers, oxidant/antioxidant status, renal mRNA expressions of TNF-α, collagen-1α, protein expressions of RIPK-1, RIPK-3, MLKL, caspase-8, HYP, MPO, and TNF-α were all significantly modulated by UUO. Administration of either SOF or EDV significantly attenuated cellular and molecular changes induced by UUO. Also, histopathological changes were improved. Moreover, SOF in combination with EDV, significantly improved UUO-induced renal fibrosis compared with each drug alone. Collectively, administration of either SOF or EDV or both of them significantly attenuated the rats with obstructive nephropathy, possibly by blocking the RIPK-3/MLKL necroptotic pathway and suppressing renal oxidative stress and inflammation.

Bulk and single-cell transcriptome profiling identify potential cellular targets of the long noncoding RNA Gas5 in renal fibrosis.

The long noncoding RNA growth arrest-specific 5 (lncRNA Gas5) is implicated in various kidney diseases. In this study, we investigated the lncRNA Gas5 expression profile and its critical role as a potential biomarker in the progression of chronic kidney disease. Subsequently, we assessed the effect of lncRNA Gas5 deletion on renal fibrosis induced by unilateral ureteral obstruction (UUO). The results indicated that loss of lncRNA Gas5 exacerbates UUO-induced renal injury and extracellular matrix deposition. Notably, the deletion of lncRNA Gas5 had a similar effect on control mice. The fibrogenic phenotype observed in mice lacking lncRNA Gas5 correlates with peroxisome proliferator-activated receptor (PPAR) signaling pathway activation and aberrant cytokine and chemokine reprogramming. Single-cell RNA sequencing analysis revealed key transcriptomic features of fibroblasts after Gas5 deletion, revealing heterogeneous cellular states suggestive of a propensity for renal fibrosis. Our findings indicate that lncRNA Gas5 regulates the differentiation and activation of immune cells and the transcription of key genes in the PPAR signaling pathway. These data offer novel insights into the involvement of lncRNA Gas5 in renal fibrosis, potentially paving the way for innovative diagnostic and therapeutic targets.

Huoxue Jiedu Huayu recipe inhibits macrophage-secreted vascular endothelial growth factor-a on angiogenesis and alleviates renal fibrosis in the contralateral kidneys of unilateral ureteral obstruction rats.

OBJECTIVE：To elucidate the mechanism by which Huoxue Jiedu Huayu recipe (, HJHR) regulates angiogenesis in the contralateral kidney of unilateral ureteral obstruction (UUO) rats and the mechanism by which it reduces of renal fibrosis. METHODS: Male Wistar rats were randomly divided into 4 groups: the sham group, UUO group (180 d of left ureter ligation), UUO plus eplerenone (EPL) group, and UUO plus HJHR group. After 180 d of oral drug administration, blood and contralateral kidneys were collected for analysis. Angiogenesis- and fibrosis-related indexes were detected. RESULTS: HJHR and EPL improved structural damage and renal interstitial fibrosis in the contralateral kidney and reduced the protein expression levels of α-smooth muscle actin (α-SMA), vimentin and collagen I. Moreover, these treatments could reduce the expression of vascular endothelial growth factor-A (VEGFA) by inhibiting the infiltration of macrophages. Furthermore, HJHR and EPL significantly reduced the expression of CD34 and CD105 by downregulating VEGFA production, which inhibited angiogenesis. Finally, the coexpressions of CD34, CD105 and α-SMA were decreased in the HJHR and EPL groups, indicating that endothelial-to-mesenchymal transition was inhibited. CONCLUSIONS: These findings confirm that HJHR alleviates contralateral renal fibrosis by inhibiting VEGFA-induced angiogenesis, encourage the use of HJHR against renal interstitial fibrosis and provide a theoretical basis for the clinical management of patients with CKD.

Renoprotective effect of rosmarinic acid by inhibition of indoxyl sulfate-induced renal interstitial fibrosis via the NLRP3 inflammasome signaling.

We previously reported that rosmarinic acid (RA) ameliorated renal fibrosis in a unilateral ureteral obstruction (UUO) murine model of chronic kidney disease. This study aimed to determine whether RA attenuates indoxyl sulfate (IS)-induced renal fibrosis by regulating the activation of the NLRP3 inflammasome/IL-1ß/Smad circuit. We discovered the NLRP3 inflammasome was activated in the IS treatment group and downregulated in the RA-treated group in a dose-dependent manner. Additionally, the downstream effectors of the NLRP3 inflammasome, cleaved-caspase-1 and cleaved-IL-1ß showed similar trends in different groups. Moreover, RA administration significantly decreased the ROS levels of reactive oxygen species in IS-treated cells. Our data showed that RA treatment significantly inhibited Smad-2/3 phosphorylation. Notably, the effects of RA on NLRP3 inflammasome/IL-1ß/Smad and fibrosis signaling were reversed by the siRNA-mediated knockdown of NLRP3 or caspase-1 in NRK-52E cells. In vivo, we demonstrated that expression levels of NLRP3, c-caspase-1, c-IL-1ß, collagen I, fibronectin and α-SMA, and TGF- ß 1 were downregulated after treatment of UUO mice with RA or RA + MCC950. Our findings suggested RA and MCC950 synergistically inhibited UUO-induced NLRP3 signaling activation, revealing their renoprotective properties and the potential for combinatory treatment of renal fibrosis and chronic kidney inflammation.

Iguratimod prevents renal fibrosis in unilateral ureteral obstruction model mice by suppressing M2 macrophage infiltration and macrophage-myofibroblast transition.

Iguratimod is a novel synthetic, small-molecule immunosuppressive agent used to treat rheumatoid arthritis. Through ongoing exploration of its role and mechanisms of action, iguratimod has been observed to have antifibrotic effects in the lung and skin; however, its effect on renal fibrosis remains unknown. This study aimed to investigate whether iguratimod could affect renal fibrosis progression. Three different concentrations of iguratimod (30 mg/kg/day, 10 mg/kg/day, and 3 mg/kg/day) were used to intervene in unilateral ureteral obstruction (UUO) model mice. Iguratimod at 10 mg/kg/day was observed to be effective in slowing UUO-mediated renal fibrosis. In addition, stimulating bone marrow-derived macrophages with IL-4 and/or iguratimod, or with TGF-ß and iguratimod or SRC inhibitors in vitro, suggested that iguratimod mitigates the progression of renal fibrosis in UUO mice, at least in part, by inhibiting the IL-4/STAT6 signaling pathway to attenuate renal M2 macrophage infiltration, as well as by impeding SRC activation to reduce macrophage-myofibroblast transition. These findings reveal the potential of iguratimod as a treatment for renal disease.

LncRNA Meg3 Aggravates Renal Fibrosis Caused by Unilateral Ureteral Obstruction in Rats by Activating the Hedgehog Pathway.

BACKGROUND: The hedgehog signaling pathway exerts vital functions in regulating epithelial-to-mesenchymal transition (EMT) in renal interstitial fibrosis (RIF). It was reported that lncRNA-maternally expressed gene 3 (lncRNA Meg3) can regulate hepatic fibrosis by regulating the expression of smoothened (Smo) in the hedgehog signaling pathway. However, the specific role of lncRNA Meg3 in renal fibrosis resulting from unilateral ureteral obstruction (UUO) by regulating the hedgehog signaling pathway has not been reported. Hence, this research aimed to expound the effects of lncRNA Meg3 on renal fibrosis induced by UUO in rats via the hedgehog pathway. METHODS: Peripheral blood was collected from patients with chronic kidney disease (CKD, CKD group) and healthy volunteers (Normal group) at the same period. In addition, 6-week-old male Sprague-Dawley (SD) rats were divided to Sham, UUO, UUO+shRNA Negative control (shNC), and UUO+sh-Meg3 groups, and their kidney tissues and serum were gathered. Next, quantitative real-time polymerase chain reaction (qRT-PCR) was employed for detecting the lncRNA Meg3 expression level in the serum of patients and renal tissue of rats; kits for testing levels of blood urea nitrogen (BUN), creatinine (Cr), hydroxyproline (HYP), and 24-hour urine protein (24-up) in rats of each group; hematoxylin and eosin (HE) staining and Masson staining for observing kidney tissue and renal fibrosis level in rats; western blot for measuring levels of collagen type III (Col III), α-Smooth muscle actin (α-SMA), fibronectin, E-cadherin, sonic hedgehog (Shh), patched (Ptch) protein, smoothened (Smo) protein and glioma-associated oncogene homolog 1 (Gli1) protein expression. RESULTS: LncRNA Meg3 was highly expressed in CKD patients and UUO rats (p < 0.01). In contrast to the UUO+shNC group, knocking down lncRNA Meg3 improved renal injury, relieved pathological renal lesions, and reduced kidney fibrosis and related protein levels. It inhibited the hedgehog pathway in kidney tissues of UUO rats (p < 0.05 and p < 0.01). CONCLUSIONS: LncRNA Meg3 can aggravate UUO-induced rat renal fibrosis by activating the hedgehog pathway.

Integrative transcriptomic and proteomic profile revealed inhibition of oxidative phosphorylation and peroxisomes during renal interstitial fibrosis.

Effective therapies of chronic kidney disease (CKD) are lacking due to the unclear molecular pathogenesis. Previous single omics-studies have described potential molecular regulation mechanism of CKD only at the level of transcription or translation. Therefore, this study generated an integrated transcriptomic and proteomic profile to provide deep insights into the continuous transcription-translation process during CKD. The comprehensive datasets identified 14,948 transcripts and 6423 proteins, 233 up-regulated and 364 down-regulated common differentially expressed genes of transcriptome and proteome were selected to further combined bioinformatics analysis. The obtained results revealed reactive oxygen species (ROS) metabolism and antioxidant system due to imbalance of mitochondria and peroxisomes were significantly repressed in CKD. Overall, this study presents a valuable multi-omics analysis that sheds light on the molecular mechanisms underlying CKD. SIGNIFICANCE: Chronic kidney disease (CKD) is a progressive and irreversible condition that results in abnormal kidney function and structure, and is ranked 18th among the leading causes of death globally, leading to a significant societal burden. Hence, there is an urgent need for research to detect new, sensitive, and specific biomarkers. Omics-based studies offer great potential to identify underlying disease mechanisms, aid in clinical diagnosis, and develop novel treatment strategies for CKD. Previous studies have mainly focused on the regulation of gene expression or protein synthesis in CKD, thereby compelling us to conduct a meticulous analysis of transcriptomic and proteomic data from the UUO mouse model. Here, we have performed a unified analysis of CKD model by integrating transcriptomes and protein suites for the first time. Our study contributes to a deeper understanding of the pathogenesis of CKD and provides a basis for subsequent disease management and drug development.

Ellagic acid ameliorates renal fibrogenesis by blocking epithelial-to-mesenchymal transition.

Objectives: Ellagic acid (EA), a kind of polyphenol found in numerous fruits and vegetables, has anti-inflammatory, anti-apoptotic, anti-oxidant, and anti-fibrotic effects against a variety of diseases, but its role in mediating renal fibrogenesis remains unknown. Materials and Methods: We used an in vivo mouse unilateral ureteral obstruction (UUO) model and an in vitro model with HK-2 cell lines treated with EA and transforming growth factor ß1 (TGF-ß1). The expression of epithelial-to-mesenchymal transition (EMT)-related proteins of UUO mice was examined using immunohistochemical staining. Liver function and renal function were evaluated using biochemical testing. Western blot analysis was used to determine the proteins related to EMT, and MTT assay was used to determine cell viability. Results: In UUO mice fed EA, both microscopical examination with immunohistochemical staining and western blotting protein analysis showed reduced expression of fibrotic (α-SMA, fibronectin, and collagen I)- and EMT (vimentin and N-cadherin)-related proteins, compared with sham control. In HK-2 cells treated with TGF-ß1, EA decreased motility as well as expression of α-SMA, collagen-I, fibronectin, N-cadherin, and vimentin. Conclusion: EA reduced the progression of the morphological transformations and concomitantly suppressed the expression of fibrotic- and EMT-related proteins in vitro and in vivo. These findings improved our understanding of the role of EA in suppressing renal fibrogenesis and demonstrated the promising role EA may play in the management of chronic kidney disease.

Herb pair of Rhubarb-Astragalus mitigates renal interstitial fibrosis through downregulation of autophagy via p38-MAPK/TGF-ß1 and p38-MAPK/smad2/3 pathways.

BACKGROUND: Chronic kidney disease (CKD) has a high incidence and poor prognosis; however, no effective treatment is currently available. Our previous study found that the improvement effect of the herb pair of Rhubarb-Astragalus on CKD is likely related to the inhibition of the TGF-ß1/p38-MAPK pathway. In the present study, a p38-MAPK inhibitor was used to further investigate the inhibitory effect of Rhubarb-Astragalus on the TGF-ß1/p38-MAPK pathway and its relationship with autophagy. METHODS: A rat model of unilateral ureteral obstruction (UUO) was established, and a subgroup of rats was administered Rhubarb-Astragalus. Renal function and renal interstitial fibrosis (RIF) were assessed 21 d after UUO induction. In vitro, HK-2 cells were treated with TGF-ß1 and a subset of cells were treated with Rhubarb-Astragalus or p38-MAPK inhibitor. Western blotting, immunohistochemistry, and qRT-PCR analyses were used to detect the relevant protein and mRNA levels. Transmission electron microscopy was used to observe autophagosomes. RESULTS: Rhubarb-Astragalus treatment markedly decreased the elevated levels of blood urea nitrogen, serum creatinine, and urinary N-acetyl-ß-D-glucosaminidase; attenuated renal damage and RIF induced by UUO; and reduced the number of autophagosomes and lysosomes in UUO-induced renal tissues. Additionally, Rhubarb-Astragalus reduced the protein and mRNA levels of α-SMA, collagen I, LC3, Atg3, TGF-ß1, p38-MAPK, smad2/3, and TAK1 in renal tissues of UUO rats. Rhubarb-Astragalus also reduced protein and mRNA levels of these indicators in vitro. Importantly, the effect of the p38-MAPK inhibitor was similar to that of Rhubarb-Astragalus. CONCLUSIONS: Rhubarb-Astragalus improves CKD possibly by downregulating autophagy via the p38-MAPK/TGF-ß1 and p38-MAPK/smad2/3 pathways.

Altenusin, a fungal metabolite, alleviates TGF-ß1-induced EMT in renal proximal tubular cells and renal fibrosis in unilateral ureteral obstruction.

Renal fibrosis is a pathological feature of chronic kidney disease (CKD), progressing toward end-stage kidney disease (ESKD). The aim of this study is to investigate the therapeutic potential of altenusin, a farnesoid X receptor (FXR) agonist derived from fungi, on renal fibrosis. The effect of altenusin was determined (i) in vitro using the transforming growth factor ß1 (TGF-ß1)-induced epithelial to mesenchymal transition (EMT) of human renal proximal tubular cells and (ii) in vivo using mouse unilateral ureteral obstruction (UUO). The findings revealed that incubation of 10 ng/ml TGF-ß1 promotes morphological change in RPTEC/TERT1 cells, a human renal proximal tubular cell line, from epithelial to fibroblast-like cells. TGF-ß1 markedly increased EMT markers namely α-smooth muscle actin (α-SMA), fibronectin, and matrix metalloproteinase 9 (MMP-9), while decreased the epithelial marker E-cadherin. Co-incubation TGF-ß1 with altenusin preserved the epithelial characteristics of the renal epithelial cells by antagonizing TGF-ß/Smad signaling pathway, specifically a decreased phosphorylation of Smad2/3 with an increased level of Smad7. Interestingly, the antagonizing effect of altenusin does not require FXR activation. Moreover, altenusin could reverse TGF-ß1-induced fibroblast-like cells to epithelial-like cells. Treatment on UUO mice with 30 mg/kg altenusin significantly reduced the expression of α-SMA, fibronectin, and collagen type 1A1 (COL1A1). The reduction in the renal fibrosis markers is correlated with the decreased phosphorylation of Smad2/3 levels but does not improve E-cadherin protein expression. Collectively, altenusin reduces EMT in human renal proximal tubular cells and renal fibrosis by antagonizing the TGF-ß/Smad signaling pathway.

Pathogenesis and management of renal fibrosis induced by unilateral ureteral obstruction.

Regardless of the underlying etiology, renal fibrosis is the final histological outcome of progressive kidney disease. Unilateral ureteral obstruction (UUO) is an ideal and reproducible experimental rodent model of renal fibrosis, which is characterized by tubulointerstitial inflammatory responses, accumulation of extracellular matrix, tubular dilatation and atrophy, and fibrosis. The magnitude of UUO-induced renal fibrosis is experimentally manipulated by the species chosen, animal age, and the severity and duration of the obstruction, while relief of the obstruction allows the animal to recover from fibrosis. The pathogenesis of renal fibrosis is complex and multifactorial and is orchestrated by activation of renin-angiotensin system (RAS), oxidative stress, inflammatory response, transforming growth factor beta 1-Smad pathway, activated myofibroblasts, cell death (apoptosis, autophagy, ferroptosis, and necroptosis), destruction of intracellular organelles, and signaling pathway. The current therapeutic approaches have limited efficacy. Inhibition of RAS and use of antioxidants and antidiabetic drugs, such as inhibitors of sodium-glucose cotransporter 2 and dipeptidyl peptidase-4, have recently gained attention as therapeutic strategies to prevent renal scarring. This literature review highlights the state of the art regarding the molecular mechanisms relevant to the management of renal fibrosis caused by UUO.

Does Hypertension Affect the Recovery of Renal Functions after Reversal of Unilateral Ureteric Obstruction?

Research has demonstrated that hypertension can lead to an exaggeration in the renal functional and histological changes caused by ureteral obstruction. These changes were particularly observed shortly after the release of a relatively brief period of unilateral ureteral obstruction (UUO). However, the long-term impact of hypertension on the recovery of renal functions has not been investigated beyond the immediate period after UUO reversal. In order to investigate this effect, a group of spontaneously hypertensive rats (G-SHR, n = 11) and a group of normotensive Wistar Kyoto rats (G-NTR, n = 11) were subjected to a 48 h reversible left UUO. The impact of UUO was then examined 45 days after the reversal of obstruction. The glomerular filtration rate, renal blood flow, and the fractional excretion of sodium in the post-obstructed left kidney (POK) showed similarities to the non-obstructed right kidney (NOK) in both groups. However, the changes in the albumin creatinine ratio, renal injury markers, pro-apoptotic markers, and histological changes in the G-SHR were much more pronounced compared to the G-NTR. We conclude that hypertension continues to have a significant impact on various aspects of renal injury and function, even several weeks after UUO reversal.

Delayed treatment with erythropoietin attenuates renal fibrosis in mouse model of unilateral ureteral obstruction.

OBJECTIVES: Erythropoietin (EPO) exerts tissue-protective effects on various organs including the kidney. However, the effects of EPO on established renal fibrosis remain unclear. In this study, we aimed to examine the therapeutic potential of EPO against established renal fibrosis. METHODS: Renal fibrosis was induced in mice by unilateral ureteral obstruction (UUO) and the mice were treated with recombinant human EPO (rhEPO) daily during 7 and 13 days after UUO. The degrees of renal fibrosis, myofibroblast accumulation, and macrophage infiltration; the mRNA expression levels of transforming growth factor (TGF)-ß1 and α1(I) collagen; and the protein levels of Kelch-like ECH-associated protein 1 (Keap1) and nuclear NF-E2-related factor 2 (Nrf2) in the kidneys were assessed on day 14 after UUO. RESULTS: Treatment with rhEPO significantly decreased fibrosis, myofibroblast accumulation, and α1(I) collagen mRNA expression, but it did not significantly affect TGF-ß1 mRNA expression. Although treatment with rhEPO did not significantly affect the total number of interstitial macrophages, it significantly decreased the number of CD86-positive cells (M1 macrophages), while significantly increased the number of CD206-positive cells (M2 macrophages) in the interstitium. Treatment with rhEPO did not affect the Keap1/Nrf2 protein level or the peripheral blood hematocrit value. CONCLUSIONS: These results indicate for the first time that EPO exerts antifibrotic effects against the evolution of established renal fibrosis, possibly by influencing the polarization of infiltrating macrophages.

Progranulin deficiency attenuates tubulointerstitial injury in a mouse unilateral ureteral obstruction model.

Progranulin (PGRN) may have two opposing effects-inflammation and anti-inflammation-in different diseases. Although previous studies have reported that PGRN is involved in liver fibrosis, its involvement in tubulointerstitial fibrosis remains to be fully elucidated. Herein, we investigated these issues using PGRN-knockout (KO) mice treated with unilateral ureteral obstruction (UUO). Eight-week-old male PGRN-KO and wild-type (WT) mice were euthanized 3 and 7 days following UUO, and their kidneys were harvested for histopathological analysis. The renal expression of PGRN was evaluated by immunohistochemical and/or western blot analyses. The renal mRNA levels of markers related to inflammation (Il1b, Tnf, Il6, Ccl2, and Adgre1) and fibrosis (Tgfb1, Acta2, Fn1, and Col1a2) were evaluated using quantitative PCR. Histological changes such as renal tubular atrophy, urinary casts, and tubulointerstitial fibrosis were significantly improved in UUO-KO mice compared with UUO-WT mice. Quantitative PCR revealed that the mRNA expression levels of all inflammation- and fibrosis-related markers were lower in UUO-KO mice than in UUO-WT mice at 3 and/or 7 days after UUO. Moreover, PGRN and GRN protein levels were higher in the kidneys of UUO-WT mice than in mice that did not undergo UUO. Elevated GRN levels associated with excess PGRN levels may be involved in the occurrence of renal inflammation and fibrosis in UUO mice.

Kidney Injury by Unilateral Ureteral Obstruction in Mice Lacks Sex Differences.

INTRODUCTION: Renal fibrosis is a critical event in the development and progression of chronic kidney disease (CKD), and it is considered the final common pathway for all types of CKD. The prevalence of CKD is higher in females; however, males have a greater prevalence of end-stage renal disease. In addition, low birth weight and low nephron number are associated with increased risk for CKD. This study examined the development and severity of unilateral ureter obstruction (UUO)-induced renal fibrosis in male and female wild-type (ROP +/+) and mutant (ROP Os/+) mice, a mouse model of low nephron number. METHODS: Male and female ROP +/+ and ROP Os/+ mice were subjected to UUO, and kidney tissue was collected at the end of the 10-day experimental period. Kidney histological analysis and mRNA expression determined renal fibrosis, tubular injury, collagen deposition, extracellular matrix proteins, and immune cell infiltration. RESULTS: Male and female UUO mice demonstrated marked renal injury, kidney fibrosis, and renal extracellular matrix production. Renal fibrosis and α-smooth muscle actin were increased to a similar degree in ROP +/+ and ROP Os/+ mice with UUO of either sex. There were also no sex differences in renal tubular cast formation or renal infiltration of macrophage in ROP +/+ and ROP Os/+ UUO mice. Interestingly, renal fibrosis and α-smooth muscle actin were 1.5-3-fold greater in UUO-ROP +/+ compared to UUO-ROP Os/+ mice. Renal inflammation phenotypes following UUO were also 30-45% greater in ROP +/+ compared to ROP Os/+ mice. Likewise, expression of extracellular matrix and renal fibrotic genes was greater in UUO-ROP +/+ mice compared to UUO-ROP Os/+ mice. In contrast to these findings, ROP Os/+ mice with UUO demonstrated glomerular hypertrophy with 50% greater glomerular tuft area compared to ROP +/+ with UUO. Glomerular hypertrophy was not sex-dependent in any of the genotypes of ROP mice. These findings provide evidence that low nephron number contributes to UUO-induced glomerular hypertrophy in ROP Os/+ mice but does not enhance renal fibrosis, inflammation, and renal tubular injury. CONCLUSION: Taken together, we demonstrate that low nephron number contributes to enhanced glomerular hypertrophy but not kidney fibrosis and tubular injury. We also demonstrate that none of the changes caused by UUO was affected by sex in any of the ROP mice genotypes.

Sulforaphane protects from kidney damage during the release of unilateral ureteral obstruction (RUUO) by activating nuclear factor erythroid 2-related factor 2 (Nrf2): Role of antioxidant, anti-inflammatory, and antiapoptotic mechanisms.

Releasing unilateral ureteral obstruction (RUUO) is the gold standard for decreasing renal damage induced during unilateral ureteral obstruction (UUO); however, the complete recovery after RUUO depends on factors such as the time and severity of obstruction and kidney contralateral compensatory mechanisms. Interestingly, previous studies have shown that kidney damage markers such as oxidative stress, inflammation, and apoptosis are present and even increase after removal obstruction. To date, previous therapeutic strategies have been used to potentiate the recovery of renal function after RUUO; however, the mechanisms involving renal damage reduction are poorly described and sometimes focus on the recovery of renal functionality. Furthermore, using natural antioxidants has not been completely studied in the RUUO model. In this study, we selected sulforaphane (SFN) because it activates the nuclear factor erythroid 2-related factor 2 (Nrf2), a transcription factor that induces an antioxidant response, decreasing oxidative stress and inflammation, preventing apoptosis. Thus, we pre-administrated SFN on the second day after UUO until day five, where we released the obstruction on the three days after UUO. Then, we assessed oxidative stress, inflammation, and apoptosis markers. Interestingly, we found that SFN administration in the RUUO model activated Nrf2, inducing its translocation to the nucleus to activate its target proteins. Thus, the Nrf2 activation upregulated glutathione (GSH) content and the antioxidant enzymes catalase, glutathione peroxidase (GPx), and glutathione reductase (GR), which reduced the oxidative stress markers. Moreover, the improvement of antioxidant response by SFN restored S-glutathionylation in the mitochondrial fraction. Activated Nrf2 also reduced inflammation by lessening the nucleotide-binding domain-like receptor family pyrin domain containing 3 and interleukin 1ß (IL-1ß) production. Reducing oxidative stress and inflammation prevented apoptosis by avoiding caspase 3 cleavage and increasing B-cell lymphoma 2 (Bcl2) levels. Taken together, the obtained results in our study showed that the upregulation of Nrf2 by SFN decreases oxidative stress, preventing inflammation and apoptosis cell death during the release of UUO.

Myricetin attenuates renal fibrosis by activating Nrf2/HO-1 pathway to inhibit oxidative stress / 药学学报

This paper investigates the effect of myricetin (MYR) on renal fibrosis induced by unilateral ureteral obstruction (UUO) and common bile duct ligation (CBDL) in mice and its mechanism. The animal experiment has been approved by the Ethics Committee of China Pharmaceutical University (NO: 2022-10-020). Thirty-five ICR mice were divided into control, UUO, UUO+MYR, CBDL and CBDL+MYR groups. H&E and Masson staining were used to detect pathological changes in kidney tissues. Western blot (WB) was used to detect the expression of fibrosis-related proteins in renal tissue, and total superoxide dismutase (SOD) activity detection kit (WST-8) was used to detect the changes of total SOD in renal tissue of CBDL mice. In vitro, HK-2 cells and transforming growth factor beta 1 (TGF-β1, 10 ng·mL-1) were used to induce fibrotic model, and high glucose (30 mmol·L-1) was used to induce oxidative stress model, and then treated with different concentrations of MYR, WB was used to detect the expression of fibrosis and oxidative stress-related proteins, while NIH/3T3 cells were treated with different concentrations of MYR, and their effects on cell proliferation were detected by 5-bromo-2′-deoxyuridine (Brdu). The results showed that the renal lesions in UUO group and CBDL group were severe, collagen deposition was obvious, the expression of collagen-Ⅰ (COL-Ⅰ), α-smooth muscle actin (α-SMA), fibronectin (FN), vimentin and plasminogen activator inhibitor-1 (PAI-1) protein was up-regulated, and the activity of SOD enzyme in CBDL group was significantly decreased. MYR partly reversed the above changes after treatment. MYR inhibited the proliferation of NIH/3T3 cells but had no effect on the proliferation of HK-2 cells, and decreased the upregulation of PAI-1, FN and vimentin in HK-2 cells stimulated by TGF-β1. MYR can also up-regulate the down-regulation of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase-1 (HO-1) in HK-2 cells stimulated by high glucose. To sum up, MYR can improve renal fibrosis in vivo and in vitro, probably by inhibiting the proliferation of fibroblasts and activating Nrf2/HO-1 signal pathway to inhibit oxidative stress.

Ootheca mantidis mitigates renal fibrosis in mice by the suppression of apoptosis via increasing the gut microbe Akkermansia muciniphila and modulating glutamine metabolism.

Renal interstitial fibrosis (RIF), a progressive process affecting the kidneys in chronic kidney disease (CKD), currently lacks an effective therapeutic intervention. Traditional Chinese medicine (TCM) has shown promise in reducing RIF and slowing CKD progression. In this study, we demonstrated the dose-dependent attenuation of RIF by Ootheca mantidis (SPX), a commonly prescribed TCM for CKD, in a mouse model of unilateral ureteral obstruction (UUO). RNA-sequencing analysis suggested that SPX treatment prominently downregulated apoptosis and inflammation-associated pathways, thereby inhibiting the fibrogenic signaling in the kidney. We further found that transplantation of fecal microbiota from SPX-treated mice conferred protection against renal injury and fibrosis through suppressing apoptosis in UUO mice, indicating that SPX ameliorated RIF via remodeling the gut microbiota and reducing apoptosis in the kidneys. Further functional exploration of the gut microbiota combined with fecal metabolomics revealed increased levels of some probiotics, including Akkermansia muciniphila (A. muciniphila), and modulations in glutamine-related amino acid metabolism in UUO mice treated with SPX. Subsequent colonization of A. muciniphila and supplementation with glutamine effectively mitigated cell apoptosis and RIF in UUO mice. Collectively, these findings unveil a functionally A. muciniphila- and glutamine-involved gut-renal axis that contributes to the action of SPX, and provide important clue for the therapeutic potential of SPX, A. muciniphila, and glutamine in combatting RIF.