Renal Interstitial Fibrosis Research Articles

Potential liquid biopsy markers of exosomal microRNAs in renal interstitial fibrosis blood and urine

ABSTRACT Objective: To explore more and better liquid biopsy markers of exosomal microRNAs (exo-miRNAs) in renal interstitial fibrosis (RIF) and to preliminary investigate the biological functions and signaling pathways involved in these markers. MATERIALS AND METHODS: High-throughput miRNA sequencing was performed on blood and urine exo-miRNAs from three RIF patients and three healthy volunteers, and differential expression analysis and bioinformatic processing were performed. Results: There were 13 differentially expressed exo-miRNA (DEexo-miRNA) between RIF and healthy blood, and 20 DEexo-miRNAs in urine. These were various DEexo-miRNAs in different specimens, and the former included PC-3p-213532_58, hsa-miR-338-5p_R-1, PC-5p-34127_410, pal-miR-9993a-3p_L+2R-1, and hsa-miR-26a-1-3p with intermediate expression levels; the latter involved hsa-miR-126-3p, hsa-miR-217-5p, hsa-miR-199b-3p_R-1, mmu-miR-5106_R-4_1ss1AG, and PC-5p-39041_356, and others, while hsa-miR-378a-3p, hsa-miR-143-3p_R+1, hsa-miR-183-5p, hsa-miR-126-3p, hsa-miR-155-5p_R-1, mmu-miR-5106_R-4_1ss1AG, hsa-miR-126-5p, and hsa-miR-199b-3p_R-1 had high expression levels. Bioinformatics analysis of the up-regulated DEmiRNA with high expression in urine showed that there are 291 target corresponding mRNAs for six of eight DEexo-miRNAs, with mmu-miR-5106_R-4_1ss1AG and hsa-miR-199b-3p_R-1 having no target gene found in TargetScan and miRanda. GO annotation revealed that GO:0005515 (protein binding) had the lowest P value, involving the most genes. KEGG analysis revealed that the signaling included the mTOR signaling pathway, autophagy - animal, etc., and hsa05200 (pathways in cancer) had a lower P value, involving the most genes. Conclusions: Urine is a better sample for RIF exo-miRNA detection than blood. Urinary exosomal hsa-miR-143-3p_R+1, hsa-miR-183-5p, hsa-miR-126-3p, mmu-miR-5106_R-4_1ss1AG, hsa-miR-126-5p, and hsa-miR-199b-3p_R-1 are novel liquid biopsy markers for RIF. These DEexo-miRNA may be associated with the occurrence and development of RIF and may participate in specific biological processes by regulating the expression of their target mRNA. Further research may require exploring the specific functions and mechanisms of these miRNAs in RIF, as well as whether they can serve as diagnostic or therapeutic targets for RIF.

TiRNA-Gly-GCC-002 promotes epithelial-mesenchymal transition and fibrosis in lupus nephritis via FKBP5-mediated activation of Smad.

Renal interstitial fibrosis is a frequent pathological manifestation of lupus nephritis (LN). tRNA halves (tiRNAs) are acquired from tRNA-derived small non-coding RNAs (sncRNAs) and are associated with fibrosis. Our previous study indicated enhanced tiRNA-Gly-GCC-002 (tiRNA002) levels in kidneys were positively related to LN-related fibrosis. However, the precise molecular mechanism remains unclear. The mimic and agomiR of tiRNA002 were introduced into tubular epithelial cells (TECs) and MRL/lpr mice by transfection. The levels of gene and protein expressions were quantified using real-time quantitative polymerase chain reaction (RT-qPCR), Western blot and immunofluorescence assays. In TECs treated with LN serum, as well as in the kidneys of MRL/lpr mice, high levels of tiRNA002 directly influenced the epithelial-mesenchymal transition (EMT) and extracellular matrix (ECM) deposition. Furthermore, tiRNA002 overexpression promoted EMT in TECs and accelerated renal interstitial fibrosis in MRL/lpr mice via Smad signalling. The target gene of tiRNA002, FKBP prolyl isomerase 5 (FKBP5), improved Smad signalling by interacting with phosphorylated Smad2/3. Silencing FKBP5 alleviated LN serum- or tiRNA002-mimic-induced EMT in TECs. In addition, FKBP5 overexpression reversed the tiRNA002 knockdown-mediated reduction of EMT and ECM accumulation. These findings indicated that tiRNA002 is markedly increased in LN, which facilitates renal fibrosis by promoting EMT via FKBP5-mediated Smad signalling. Therefore, targeting tiRNA002 may be an innovative approach to treat renal interstitial fibrosis in LN.

Empagliflozin attenuating renal interstitial fibrosis in diabetic kidney disease by inhibiting lymphangiogenesis and lymphatic endothelial-to-mesenchymal transition via the VEGF-C/VEGFR3 pathway

Renal interstitial fibrosis (RIF) is a significant pathological change in diabetic kidney disease (DKD) that can be induced by endothelial-to-mesenchymal transition (EndMT). Lymphangiogenesis, mediated by the vascular endothelial growth factor-C (VEGF-C)/vascular endothelial growth factor receptor-3 (VEGFR-3) pathway, plays a crucial role in the development of RIF in DKD. Although numerous studies have demonstrated the efficacy of empagliflozin in treating renal injury, its effects on lymphangiogenesis in DKD-related RIF and the underlying mechanisms remain unclear. In the present study, significant lymphangiogenesis was assessed in the renal interstitium of patients with DKD. We subsequently explored the relationship between DKD-related RIF and lymphangiogenesis in mouse models, high-glucose (HG)-stimulated renal HK-2 cell lines, and human lymphatic endothelial cells (hLECs). Additionally, we evaluated the effects of empagliflozin on these processes. The results revealed that HG induces lymphangiogenesis, which exacerbates RIF by promoting inflammatory responses. Furthermore, hLECs directly contributed to the progression of DKD-related RIF through EndMT. Further analysis revealed that tubular epithelial cells (TECs) act as effector cells for VEGF-C, with the epithelial-to-mesenchymal transition (EMT) of TECs occurring concurrently with the EndMT of lymphatic vessels. Empagliflozin inhibited RIF in DKD by suppressing the VEGF-C/VEGFR3 pathway and reducing lymphangiogenesis. In conclusion, this study elucidates the interplay between lymphangiogenesis, EndMT, and RIF in DKD and provides new insights into the mechanism by which empagliflozin treats DKD.

High glucose-induced senescence contributes to tubular epithelial cell damage in diabetic nephropathy

Dysfunctional renal tubular epithelial cells, induced by high glucose, are commonly observed in the kidney tissues of diabetic nephropathy (DN) patients. The epithelial-mesenchymal transition (EMT) of these cells often leads to renal interstitial fibrosis and kidney damage in DN. High glucose also triggers mitochondrial damage and apoptosis, contributing further to the dysfunction of renal tubular epithelial cells. Cellular senescence, a recognized characteristic of DN, is primarily caused by high glucose. However, it remains unclear whether high glucose-induced cellular senescence in DN exacerbates the functional impairment of tubular epithelial cells. In this study, we examined the relationship between EMT and cellular senescence in kidney tissues from streptozotocin (STZ)-induced DN and HK-2 cells treated with high glucose (HG). We also investigated the impact of HG concentrations on tubular epithelial cells, specifically mitochondrial dysfunction, cellular senescence and apoptosis. These damages were primarily associated with the secretion of cytokines (such as IL-6, and TNF-α), production of reactive oxygen species (ROS), and an increase of intracellular Ca2+. Notably, resveratrol, an anti-aging agent, could effectively attenuate the occurrence of EMT, mitochondrial dysfunction, and apoptosis induced by HG. Mechanistically, anti-aging treatment leads to a reduction in cytokine secretion, ROS production, and intracellular Ca2+ levels.

S100A2 activation promotes interstitial fibrosis in kidneys by FoxO1-mediated epithelial-mesenchymal transition

BackgroundRenal interstitial fibrosis (RIF) is a common feature of chronic kidney diseases (CKD), with epithelial-mesenchymal transition (EMT) being one of its important mechanisms. S100A2 is a protein associated with cell proliferation and differentiation, but its specific functions and molecular mechanisms in RIF remain to be determined.MethodsS100A2 levels were evaluated in three mouse models, including unilateral ureteral obstruction (UUO), ischemia-reperfusion injury (IRI), and aristolochic acid nephropathy (AAN), as well as in TGF-β1- treated HK-2 cells and in kidney tissue samples. Furthermore, the role of S100A2 and its interaction with FoxO1 was investigated using RT-qPCR, immunoblotting, immunofluorescence staining, co-immunoprecipitation (Co-IP), transcriptome sequencing, and gain- or loss-of-function approaches in vitro.ResultsElevated expression levels of S100A2 were observed in three mouse models and TGF-β1-treated HK2 cells, as well as in kidney tissue samples. Following siRNA silencing of S100A2, exposure to TGF-β1 in cultured HK-2 cells suppressed EMT process and extracellular matrix (ECM) accumulation. Conversely, Overexpression of S100A2 induced EMT and ECM deposition. Notably, we identified that S100A2-mediated EMT depends on FoxO1. Immunofluorescence staining indicated that S100A2 and FoxO1 colocalized in the nucleus and cytoplasm, and their interaction was verified in Co-IP assay. S100A2 knockdown decreased TGF-β1-induced phosphorylation of FoxO1 and increased its protein expression, whereas S100A2 overexpression hampered FoxO1 activation. Furthermore, pharmacological blockade of FoxO1 rescued the induction of TGF-β1 on EMT and ECM deposition in S100A2 siRNA-treated cells.ConclusionS100A2 activation exacerbates interstitial fibrosis in kidneys by facilitating FoxO1-mediated EMT.Graphical abstractA schematic diagram of the underlying mechanisms by which S100A2 regulates EMT and renal fibrosis. Following injury, the cytoplasmic expression of S100A2 in renal tubular epithelial cells is markedly elevated. This increase promotes the phosphorylation of FoxO1, preventing its translocation into the nucleus and enhances EMT and extracellular matrix ECM deposition, thereby exacerbating renal interstitial fibrosis.

Renal protection of HWL-088 and ZLY032, two dual GPR40/PPARδ agonists, in adenine-induced renal fibrosis model.

This research examined the potential of novel GPR40/PPARδ dual agonists, HWL-088 and ZLY-032, to protect the kidneys in a mouse model of adenine-induced renal fibrosis. Mice were given a diet containing 0.25% adenine to develop renal fibrosis and then received different dosages of HWL-088 or ZLY-032. After being euthanized, tissue and serum samples were collected for morphological, histological, and molecular examination. Compared to the control group, mice fed adenine showed an increase in kidney-to-body weight ratio, serum creatinine, and urea levels. Hematoxylin and eosin staining revealed alleviated glomerulosclerosis, tubular dilation, and inflammatory cell infiltration in mice treated with HWL-088 or ZLY-032. Furthermore, Masson staining and immunohistochemistry demonstrated that these dual agonists protected against renal interstitial fibrosis and inflammation, corroborated by decreased expression levels of fibrosis-related proteins (TGF-β, Collα1, TIMP-1) and pro-inflammatory cytokines (TNF-α, IL-1β, IL-6). Accordingly, it can be inferred that GPR40/PPARδ dual agonists HWL-088 and ZLY-032 could yield significant renoprotective effects by inhibiting inflammation and fibrosis. Overall, these results may contribute to the development of novel therapeutic strategies for renal fibrosis.

Integrative Multi-Omics and Network Pharmacology Reveal the Mechanisms of Fangji Huangqi Decoction in Treating IgA Nephropathy

Ethnopharmacological relevanceFangji Huangqi Decoction (FJHQD), a classical Chinese herbal formulation, has demonstrated significant clinical efficacy in the treatment of IgA nephropathy (IgAN), although its mechanisms remain poorly understood. Aim of the studyThis study aims to investigate the renal protective mechanisms of FJHQD using an integrated approach that combines transcriptomics, proteomics, and network pharmacology. MethodsRenal glomerular structure changes were assessed via hematoxylin and eosin (H&E) and Masson staining. IgA expression in the glomeruli was quantified using immunofluorescence. Furthermore, the potential mechanisms underlying the effects of FJHQD were explored through a combined strategy of network pharmacology, transcriptomics, and proteomics. The expression of signaling pathway-related proteins was detected using Western blot. ResultsFJHQD inhibited mesangial cell proliferation and renal interstitial fibrosis, and significantly reduced excessive IgA deposition in the glomerular mesangium. Network pharmacology identified 113 important active components and 8 common active components in FJHQD, with quercetin, isorhamnetin, jaranol, and kaempferol having the highest number of target interactions. Integration of network pharmacology with multi-omics approaches revealed that 44 active components regulated numerous immune and inflammatory signaling pathways through 17 hub targets. These pathways include the Calcium signaling pathway, cAMP signaling pathway, Ras signaling pathway, MAPK signaling pathway, and PI3K-AKT signaling pathway. Subsequent in vivo experiments demonstrated that FJHQD effectively regulates the identified pathways in IgAN mice. Ultimately, molecular docking results further validated the reliability of the network pharmacology combined with multi-omics analyses. ConclusionThe findings suggest that FJHQD exerts a renal protective effect, potentially through modulation of the Calcium signaling pathway, cAMP signaling pathway, Ras signaling pathway, MAPK signaling pathway, and PI3K-AKT signaling pathway. These insights offer valuable support for the clinical use of FJHQD and open new avenues for exploring the active compounds and molecular mechanisms of Traditional Chinese Medicines (TCMs).

Renal fibroblasts are involved in fibrogenic changes in kidney fibrosis associated with dysfunctional telomeres.

Tubulointerstitial fibrosis associated with chronic kidney disease (CKD) represents a global health care problem. We previously reported that short and dysfunctional telomeres lead to interstitial renal fibrosis; however, the cell-of-origin of kidney fibrosis associated with telomere dysfunction is currently unknown. We induced telomere dysfunction by deleting the Trf1 gene encoding a telomere-binding factor specifically in renal fibroblasts in both short-term and long-term life-long experiments in mice to identify the role of fibroblasts in renal fibrosis. Short-term Trf1 deletion in renal fibroblasts was not sufficient to trigger kidney fibrosis but was sufficient to induce inflammatory responses, ECM deposition, cell cycle arrest, fibrogenesis, and vascular rarefaction. However, long-term persistent deletion of Trf1 in fibroblasts resulted in kidney fibrosis accompanied by an elevated urinary albumin-to-creatinine ratio (uACR) and a decrease in mouse survival. These cellular responses lead to the macrophage-to-myofibroblast transition (MMT), endothelial-to-mesenchymal transition (EndMT), and partial epithelial-to-mesenchymal transition (EMT), ultimately causing kidney fibrosis at the humane endpoint (HEP) when the deletion of Trf1 in fibroblasts is maintained throughout the lifespan of mice. Our findings contribute to a better understanding of the role of dysfunctional telomeres in the onset of the profibrotic alterations that lead to kidney fibrosis.

Dang-Gui-Bu-Xue decoction against diabetic nephropathy via modulating the carbonyl compounds metabolic profile and AGEs/RAGE pathway

BackgroundDang-Gui-Bu-Xue decoction (DBD) is a traditional Chinese medicine prescription clinically employed for diabetic nephropathy (DN). However, the components and pharmacological mechanisms of DBD against DN remain incompletely understood. PurposeTo clarify the beneficial effect of DBD on DN and to explore its nephroprotective effect's probable mechanism and the main components. MethodsA diabetic mice model was established by feeding a high-fat diet (HFD) and intraperitoneal injections of streptozotocin (STZ, 40 mg‧kg-1). Subsequently, the mice were maintained on a HFD and administered with DBD. The benefits of DBD against DN were comprehensively assessed by monitoring energy and water intake, blood glucose and lipids, renal functions and pathological status. The UPLC-MS/MS was measured to detect chemical constituents in DBD and absorbed components in DBD-treated plasma under physiological and pathological states. Network pharmacology was employed to forecast the probable pathways of DBD intervention in DN, with subsequent validation of these predictions through testing biochemical parameters, anti-glycation and ELISA assays, immunofluorescence, immunohistochemistry, and western blotting. Then, a chemical derivatization method paired with UPLC-MS/MS analysis was performed to detect the carbonyl compounds in renal tissue. Finally, the main components of DBD against DN were screened by anti-glycation and MTT assays. ResultsDBD regulated energy and water intakes, glucose and lipid metabolism disorders, renal dysfunction, glomerular filtration rate, renal interstitial glycogen accumulation and fibrosis in HFD/STZ-induced DN mice. A total of 129 distinct chemical constituents in DBD were characterized, of which 28 were detected in the DBD-treated plasma under a pathological state. The network pharmacological results suggested AGEs/RAGE and its downstream pathway may be a potential pathway for DBD intervention in DN. Further experiments confirmed that DBD reduced renal oxidative stress by modulating the AGEs/RAGE pathway. Moreover, 21 differential carbonyl compounds were detected between normal and DN mice, and DBD significantly modulated 16. Ultimately, seven components were screened out in DBD, which may be the main components of DBD regulating carbonyl compounds metabolic profile and AGEs/RAGE pathway. ConclusionOur findings suggested for the first time that DBD could regulate the carbonyl compounds metabolic profile and AGEs/RAGE signaling pathway to ameliorate DN.

Kaempferol attenuates cyclosporine-induced renal tubular injury via inhibiting the ROS-ASK1-MAPK pathway.

Cyclosporine (CSA) is a widely used immunosuppressive medication. CSA nephrotoxicity severely limits its application. Kaempferol (KPF), a naturally occurring phenolic compound, has a promising protective effect in reducing CSA-induced renal tubular injury, but the mechanism remains unknown. Our study aimed to determine the protective role of KPF against CSA-induced renal tubular injury. C57/B6 mice and the NRK-52E cell line were employed. CSA worsened renal function in mice, causing detachment and necrosis of tubular cells, leading to tubular vacuolation and renal interstitial fibrosis. CSA caused the detachment, rupture, and death of tubular cells in vitro, resulting in cell viability loss. KPF mitigated all these injurious alterations. KPF hindered CSA-induced ROS generation and protected renal tubular epithelial cells, similar to the antioxidant NAC. CSA lowered SOD activity and GSH levels while increasing MDA levels, and KPF ameliorated these changes. CSA caused phosphorylation of ASK1, JNK, and p38, similar to H2O2, whereas KPF significantly inhibited these changes. In conclusion, KPF reduces CSA-induced tubular epithelial cell injury via its antioxidant properties, inhibits the phosphorylation of ASK1, and inhibits the phosphorylation of p38 and JNK, implying that the synergistic use of KPF in CSA immunotherapy may be a promising option to reduce CSA-evoked renal injury.

Overexpression of PRDM16 attenuates acute kidney injury progression: genetic and pharmacological approaches.

Acute kidney injury (AKI) presents as a condition marked by a sudden and rapid decrease in kidney function over a short timeframe, resulting from diverse causes. As a transcription factor, PR domain-containing 16 (PRDM16), has recently been implicated in brown fat biogenesis and heart diseases. Our recent works indicated that PRDM16 could suppress the occurrence of renal interstitial fibrosis in diabetic kidney disorder. Nonetheless, the effect and regulatory mechanism of PRDM16 in AKI remain elusive. Our study demonstrated that PRDM16 inhibited apoptosis induced by ischemic/reperfusion (I/R) in BUMPT (Boston University mouse kidney proximal tubular) cells and HK-2(Human Kidney-2)cells. Mechanistically, PRDM16 not only bound to the promoter region of S100 Calcium Binding Protein A6 (S100A6)and upregulated its expression but also interacted with its amino acids 945-949, 957-960, and 981-984 to suppress the p38MAPK and JNK axes via inhibition of PKC-η activity and mitochondrial reactive oxygen species (ROS) production. Furthermore, cisplatin- and I/R-stimulated AKI progression were ameliorated in PRDM16 proximal-tubule-specific knockin mice, whereas exacerbated in PRDM16 knockout proximal-tubule-specific mice). Moreover, we observed that formononetin ameliorated I/R- and cisplatin-triggered AKI progression in mice. Taken together, these findings reveal a novel self-protective mechanism in AKI, whereby PRDM16 regulates the S100A6/PKC-η/ROS/p38MAPK and JNK pathways to inhibit AKI progression.

Comparative Study Between Variable Flip Angle and Modified Look-Locker Inversion Recovery for Evaluating Renal Interstitial Fibrosis.

Variable flip angle (VFA) and modified Look-Locker inversion recovery (MOLLI) are frequently used for noninvasive evaluation of renal interstitial fibrosis (IF) in chronic kidney disease (CKD). However, controversy remains over which method is preferred. To compare the diagnostic efficacy of VFA and MOLLI for T1 mapping in evaluating renal IF. Prospective. Fifty-one participants with CKD (CKD stage 1-5, 35 males) and 18 healthy volunteers (eight males). 3.0 T, three-dimensional gradient echo sequence for B1+ VFA, and two-dimensional gradient echo sequence for MOLLI. Image quality was assessed on a five-point scale. Cortex and medulla T1 values (cT1 and mT1), corticomedullary T1 value difference (ΔT1, medulla - cortex), and corticomedullary T1 value ratio (ratio T1, cortex:medulla) were compared between VFA and MOLLI as well as between IF grade (0-4) based on biopsy. Intraclass correlation coefficient, Bland-Altman analysis, analysis of variance, Kruskal-Wallis test, correlation analysis, and receiver operating characteristics analysis with the area under the curve (AUC). P-value <0.05 was considered significant. MOLLI provided significantly better image quality compared to VFA. cT1 and mT1 values significantly differed between VFA and MOLLI (cT1-VFA: 1771.4 ± 139.4 msec vs. cT1-MOLLI: 1729.9 ± 132.1 msec; mT1-VFA: 2076.0 [interquartile range (IQR): 2045.9-2129.9] msec vs. mT1-MOLLI: 2039.2 [IQR: 1997.8-2071.6] msec). ΔT1 and ratio T1 values were not different between VFA and MOLLI (ΔT1: 300.8 ± 71.4 vs. 306.0 ± 78.4, respectively, P = 0.33 and ratio T1: 0.85 ± 0.038 vs. 0.85 ± 0.041, respectively, P = 0.064). No difference was observed between T1 variables and T1 mapping methods in diagnosing IF. ΔT1 and ratio T1 were not different between VFA and MOLLI. Both VFA and MOLLI are effective for noninvasive assessment of renal IF. 2 TECHNICAL EFFICACY: Stage 2.

322.8: Rictor/mTORC2 signaling contributes to renal vascular endothelial-to-mesenchymal transition and renal allograft interstitial fibrosis by regulating BNIP3-mediated mitophagy.

322.8: Rictor/mTORC2 signaling contributes to renal vascular endothelial-to-mesenchymal transition and renal allograft interstitial fibrosis by regulating BNIP3-mediated mitophagy.

P.060: Deletion of β-catenin in macrophages alleviates transplanted renal interstitial fibrosis by inhibiting pericyte-to-myofibroblast transformation.

P.060: Deletion of β-catenin in macrophages alleviates transplanted renal interstitial fibrosis by inhibiting pericyte-to-myofibroblast transformation.

Abstract 03: Glomerular Hyperfiltration Promotes Chronic Kidney Disease through Interleukin 17A-Mediated Inflammation

Impaired renal autoregulation in obesity, diabetes and hypertension (HTN) causes elevated glomerular capillary pressure and glomerular hyperfiltration, initiating progressive glomerulosclerosis (GS), nephron loss and chronic kidney disease (CKD). Increased renal perfusion pressure drives renal T cell infiltration. T helper (Th) 17 cells promote vascular stiffening in HTN and renal interstitial fibrosis post AKI, but their roles in GS and CKD are poorly understood. We hypothesized that glomerular hyperfiltration promotes CKD through Th17-mediated GS and tested the hypothesis in 129S6 mice using the reduced kidney mass model (RKM) induced by uninephrectomy and partial renal artery ligation in the remaining kidney (functional renal mass reduced by ~ 5/6). BP (radiotelemetry) and GFR (FITC-sinistrin) of RKM mice were identical to sham controls at baseline (BL, n=4-6). Immediately after the RKM procedure, GFR dropped to 22% of BL, consistent with the extent of renal mass ablation. Mean BP increased by 29 mmHg first week after 5/6 ablation (144 ± 8 vs BL 112 ± 2 mmHg, p&lt;0.05, 2-way ANOVA) and remained elevated through week 12, exposing the remnant nephrons to increased renal perfusion pressure. Serum creatinine, BUN and urinary albumin were significantly elevated after 5/6 ablation. In RKM mice, GFR gradually increased to 38% of BL at day 3, 57% at week 1 and 68% at week 2, suggesting that systemic HTN and impaired renal autoregulation may have caused substantial single-nephron hyperfiltration in the remnant kidney. GFR plateaued at ~ 70% of BL in week 3-4 then declined to 48% at week 8 when glomerular, interstitial, and microvascular fibrosis developed as evidence by Periodic Acid Schiff and Picro Sirius Red staining. Importantly, the early adaptive increase of GFR in the first 2 weeks post 5/6 ablation was accompanied by a striking increase of renal interleukin (IL)-17A+ T cells, which preceded the late infiltration of CD11b+ myeloid cells, F4/80+ monocyte/macrophages, and T regulatory cells. Anti-IL17A antibodies (eBioMM17F3, 100 μg i.p. twice weekly) attenuated the early hyperfiltration, abolished aortic/renal inflammation, and prevented GFR decline and GS at week 8 in male but not female RKM mice, likely due to the anti-hypertensive and anti-inflammatory effects of IL-17A neutralization. We conclude that glomerular hyperfiltration causes progressive nephron loss and kidney fibrosis in CKD, at least in part, through IL-17A mediated renal inflammation.

Renal Fibrosis: SIRT1 Still of Value.

Chronic kidney disease (CKD) is a major global health concern. Renal fibrosis, a prevalent outcome regardless of the initial cause, ultimately leads to end-stage renal disease. Glomerulosclerosis and renal interstitial fibrosis are the primary pathological features. Preventing and slowing renal fibrosis are considered effective strategies for delaying CKD progression. However, effective treatments are lacking. Sirtuin 1 (SIRT1), a nicotinamide adenine dinucleotide (NAD+)-dependent deacetylase belonging to class III histone deacetylases, is implicated in the physiological regulation and protection of the kidney and is susceptible to a diverse array of pathological influences, as demonstrated in previous studies. Interestingly, controversial conclusions have emerged as research has progressed. This review provides a comprehensive summary of the current understanding and advancements in the field; specifically, the biological roles and mechanisms of SIRT1 in regulating renal fibrosis progression. These include aspects such as lipid metabolism, epithelial-mesenchymal transition, oxidative stress, aging, inflammation, and autophagy. This manuscript explores the potential of SIRT1 as a therapeutic target for renal fibrosis and offers new perspectives on treatment approaches and prognostic assessments.

Activation of NLRP3 inflammasome in patients with renal transplantation: relation to allograft dysfunction, inflammation, and renal fibrosis

ABSTRACT Background Chronic allograft dysfunction (CAD) represents a complex process of inflammatory response, fibrosis, and tissue restoration, mediated by a myriad of proinflammatory cytokines, enzymes, and growth factors. NOD-like receptor protein3 (NLRP3) inflammasome is one of the NLR protein families. It drives proteolysis of proinflammatory caspases which induces maturation of pro-interleukin (IL)-1β and pro-IL-18. The aim of this work is to study NLRP3 inflammasome activation in patients with renal transplantation in relation to allograft function, inflammation, and renal fibrosis. Methods Thirty renal transplant recipients (RTR): 15 patients with stable renal function (Group I), 15 patients with CAD (Group II), and 15 healthy subjects (Group III) were included. Serum and urinary NLRP3, caspase-1, and interleukin-1β were measured using an enzyme-linked immunosorbent assay (ELISA) kit. Serum high sensitivity C-reactive protein (hs-CRP) level was measured, and neutrophil-lymphocyte ratio (NLR) was calculated. Renal function was evaluated by serum creatinine (S.Cr) and estimated glomerular filtration rate (eGFR). Resistive index (RI) was calculated with Doppler ultrasonography. In patients with CAD, renal interstitial fibrosis (RIF) was graded in renal biopsies. Results Serum NLRP3, caspase-1, serum and urinary IL-1β, and hs-CRP showed a statistically significant increase in RTR, particularly in those with CAD compared to the controls with a positive correlation with each other, their urinary level, S. Cr, hs-CRP, NLR, RI, and RIF (p < 0.001). The receiver operating characteristic curve showed high diagnostic accuracy of serum NLRP3, caspase-1, and IL-1β in discriminating patients with CAD from patients with stable renal function. Conclusion The NLRP3-caspase1-IL-1β cascade is activated and upregulated in renal transplant recipients, particularly those with advanced renal impairment, and thus may play a role in developing CAD and renal fibrosis. They could be potential biomarkers for post-transplant outcome, follow-up, and early diagnosis. Moreover, their cascade could be a target for future anti-inflammatory therapeutic strategies for allograft dysfunction.

Reduction in Renal Interstitial Fibrosis in Aged Male Mice by Intestinal Microbiota Rejuvenation.

Renal interstitial fibrosis is an important pathological basis for kidney ageing and the progression of ageing nephropathy. In the present research, we established an aged mouse model of faecal microbiota transplantation (FMT), identified the rejuvenation features of the kidney in aged male mice, and preliminarily analysed the possible mechanism by which the rejuvenation of the intestinal microbiota reduces renal interstitial fibrosis and delays senescence in aged male mice. We established an aged male mice model that was treated with FMT (FMT-Old) and a normal aged male mice control group (Old). Differentially expressed cytokines were identified using a cytokine array, and changes in protein expression related to signal transduction pathways in renal tissues were detected using a signalling pathway array. Senescence-associated β-galactosidase and Masson staining were performed to observe the degrees of renal senescence and tubule interstitial fibrosis. Immunohistochemistry was utilized to detect changes in the expression of the ageing markers p53 and p21 and the inflammation-related protein nuclear factor (NF-κB) subunit (RelA/p65). The pathological features of renal senescence in the FMT-Old group were significantly alleviated, and the levels of the ageing indicators p53 and p21 were decreased (p &lt; 0.05). Ingenuity Pathway Analysis revealed that six differentially expressed cytokines, MIP-3β (CCL-19), E-selectin (SELE), Fas ligand (Fas L/FASLG), CXCL-11 (I-TAC), CXCL-1 and CCL-3 (MIP-1α) were related to a common upstream regulatory protein, RelA/p65, and the expression of this protein was significantly different between groups according to the signalling pathway array. Our findings suggest that the intestinal microbiota regulates the renal microenvironment by reducing immune inflammatory responses through the inhibition of the NF-κB signalling pathway, thereby delaying renal senescence in aged male mice.

Endothelial Birc3 promotes renal fibrosis through modulating Drp1-mediated mitochondrial fission via MAPK/PI3K/Akt pathway

Renal fibrosis serves as the shared pathway in chronic kidney disease (CKD) progression towards end-stage renal disease (ESRD). Endothelial-mesenchymal transition (EndMT) is a vital mechanism leading to the generation of myofibroblasts, thereby contributing to the advancement of fibrogenesis. Baculoviral IAP Repeat Containing 3(Birc3) was identified as a crucial inhibitor of cell death and a significant mediator in inflammatory signaling and immunity. However, its involvement in the development of renal interstitial fibrosis via EndMT still needs to be clarified. Herein, elevated levels of Birc3 expression along with EndMT-associated alterations, including increased α-smooth muscle actin (α-SMA) levels and decreased CD31 expression, were observed in fibrotic kidneys of Unilateral Ureteral Obstruction (UUO)-induced mouse models and transforming growth factor-β (TGF-β)-induced EndMT in Human Umbilical Vein Endothelial Cells (HUVECs). Functionally, Birc3 knockdown inhibited EndMT and mitochondrial fission mediated by dynamin-related protein 1 (Drp1) both in vivo and in vitro. Mechanistically, endothelial Birc3 exacerbated Drp-1-induced mitochondrial fission through the MAPK/PI3K/Akt signaling pathway in endothelial cell models stimulated TGF-β. Collectively, these findings illuminate the mechanisms and indicate that targeting Birc3 could offer a promising therapeutic strategy to improve endothelial cell survival and mitigate the progression of CKD.

Alantolactone alleviates epithelial-mesenchymal transition by regulating the TGF-β/STAT3 signaling pathway in renal fibrosis

ObjectiveThe epithelial-to-mesenchymal transition (EMT) of renal tubular epithelial cells (RTECs) plays a crucial role in renal interstitial fibrosis and inflammation, which are key components of chronic kidney disease (CKD). Alantolactone, a selective inhibitor of signal transducer and activator of transcription 3 (STAT3), is used in Chinese herbal medicine. Despite its use, the effects of alnatolactone on EMT of RTECs has not been fully elucidated. MethodsIn this study, we investigated the potential of alantolactone to EMT in vivo and in vitro. Our experiments were performed using a unilateral ureteral obstruction (UUO) models and HK-2 cells, RTECs, treated with transforming growth factor (TGF-β). ResultsAlantolactone decreased tubular injury and reduced the expression of vimentin, a key EMT marker, while increasing E-cadherin expression in UUO kidneys. Similarly, in RTECs, alantolactone inhibited TGF-β-induced EMT and its markers. Furthermore, alantolactone attenuated UUO- and TGF-β-induced STAT3 phosphorylation both in vivo and in vitro, and inhibited the expression of TWIST, an EMT transcription factor, in both models. ConclusionAlantolactone improves EMT in RTECs by inhibiting STAT3 phosphorylation and Twist expression, suggesting its potential as a therapeutic agent for kidney fibrosis.