Mouse Kidney Research Articles

LncRNA SNHG14 silencing attenuates the progression of diabetic nephropathy via the miR-30e-5p/SOX4 axis.

Diabetic nephropathy (DN) is a diabetic complication. LncRNAs are reported to participate in the pathophysiology of DN. Here, the function and mechanism of lncRNA small nucleolar RNA host gene 14 (SNHG14) in DN were explored. Streptozotocin (STZ)-induced DN mouse models and high glucose (HG)-treated human mesangial cells (MCs) were used to detect SNHG14 expression. SNHG14 silencing plasmids were applied to examine the function of SNHG14 on proliferation and fibrosis in HG-treated MCs. Potential targets of SNHG14 were predicted using bioinformatics tools and verified by luciferase reporter, RNA pulldown, and northern blotting assays. The functional role of SNHG14 in DN in vivo was detected by injection with adenoviral vector carrying sh-SNHG14 into DN mice. Serum creatinine, blood urea nitrogen, blood glucose, 24-h proteinuria, relative kidney weight, and renal pathological changes were examined in DN mice. SNHG14 expression was elevated in the kidneys of DN mice and HG-treated MCs. SNHG14 silencing inhibited proliferation and fibrosis of HG-stimulated MCs. SNHG14 bound to miR-30e-5p to upregulate SOX4 expression. In rescue assays, SOX4 elevation diminished the effects of SNHG14 silencing in HG-treated MCs, and SOX4 silencing reversed the effects of SNHG14 overexpression. In in vivo studies, SNHG14 downregulation significantly ameliorated renal injuries and renal interstitial fibrosis in DN mice. SNHG14 silencing attenuates kidney injury in DN mice and reduces proliferation and fibrotic phenotype of HG-stimulated MCs via the miR-30e-5p/SOX4 axis.

C-Cbl induced podocin ubiquitination contributes to the podocytes injury in diabetic nephropathy.

The ubiquitination function in diabetic nephropathy (DN) has attracted much attention, but there is a lack of information on its ubiquitylome profile. To examine the differences in protein content and ubiquitination in the kidney between db/db mice and db/m mice, we deployed liquid chromatography-mass spectrometry (LC-MS/MS) to conduct analysis. We determined 145 sites in 86 upregulated modified proteins and 66 sites in 49 downregulated modified proteins at the ubiquitinated level. Moreover, 347 sites among the 319 modified proteins were present only in the db/db mouse kidneys, while 213 sites among the 199 modified proteins were present only in the db/m mouse kidneys. The subcellular localization study indicated that the cytoplasm had the highest proportion of ubiquitinated proteins (31.87%), followed by the nucleus (30.24%) and the plasma membrane (20.33%). The enrichment analysis revealed that the ubiquitinated proteins are mostly linked to tight junctions, oxidative phosphorylation, and thermogenesis. Podocin, as a typical protein of slit diaphragm, whose loss is a crucial cause of proteinuria in DN. Consistent with the results of ubiquitination omics, the K261R mutant of podocin induced the weakest ubiquitination compared with the K301R and K370R mutants. As an E3 ligase, c-Cbl binds to podocin, and the regulation of c-Cbl can impact the ubiquitination of podocin. In conclusion, in DN, podocin ubiquitination contributes to podocyte injury, and K261R is the most significant site. c-Cbl participates in podocin ubiquitination and may be a direct target for preserving the integrity of the slit diaphragm structure, hence reducing proteinuria in DN.

Crosstalk among proximal tubular cells, macrophages, and fibroblasts in acute kidney injury: single-cell profiling from the perspective of ferroptosis.

The link between ferroptosis, a form of cell death mediated by iron and acute kidney injury (AKI) is recently gaining widespread attention. However, the mechanism of the crosstalk between cells in the pathogenesis and progression of acute kidney injury remains unexplored. In our research, we performed a non-negative matrix decomposition (NMF) algorithm on acute kidney injury single-cell RNA sequencing data based specifically focusing in ferroptosis-associated genes. Through a combination with pseudo-time analysis, cell-cell interaction analysis and SCENIC analysis, we discovered that proximal tubular cells, macrophages, and fibroblasts all showed associations with ferroptosis in different pathways and at various time. This involvement influenced cellular functions, enhancing cellular communication and activating multiple transcription factors. In addition, analyzing bulk expression profiles and marker genes of newly defined ferroptosis subtypes of cells, we have identified crucial cell subtypes, including Egr1 + PTC-C1, Jun + PTC-C3, Cxcl2 + Mac-C1 and Egr1 + Fib-C1. All these subtypes which were found in AKI mice kidneys and played significantly distinct roles from those of normal mice. Moreover, we verified the differential expression of Egr1, Jun, and Cxcl2 in the IRI mouse model and acute kidney injury human samples. Finally, our research presented a novel analysis of the crosstalk of proximal tubular cells, macrophages and fibroblasts in acute kidney injury targeting ferroptosis, therefore, contributing to better understanding the acute kidney injury pathogenesis, self-repairment and acute kidney injury-chronic kidney disease (AKI-CKD) progression.

CCR2/CCR5 antagonist cenicriviroc reduces colonic inflammation and fibrosis in experimental colitis.

Cenicriviroc (CVC) is a CCR2/CCR5 antagonist that has been shown to be effective in the treatment of inflammatory and fibrotic diseases. Our study evaluated its efficacy in colitis. Mouse models of DSS-induced acute and chronic colitis were established. The efficacy of CVC in colitis was assessed by disease activity index (DAI) scores, histological assessment of inflammation and fibrosis, and expression assays of key molecules. In in vitro experiments, HT29 cell line was exposed to TNFα to study inflammatory signaling in intestinal epithelial cells. CCD-18Co colonic myofibroblasts and human primary colonic fibroblasts were activated by TGFβ1 to mimic fibroblast activation. In HT29 cells, CVC significantly reduced mRNA expression of CCL5 (P<0.01) but had no effect on CCL2. Furthermore, CVC reduced downstream CX3CL1 (P<0.01) and TNFα (P<0.05) expression, thereby inhibiting inflammatory progression. In acute colitis mice, CVC significantly reduced DAI scores and serum TNFα levels (P<0.05) and attenuated colonic inflammation as shown by HE staining. Meanwhile, CVC had no adverse effects on the liver, heart, and kidney of mice. On the other hand, in cellular models of chronic colitis, CVC decreased the expression of fibrosis markers, including FN, CTGF, α-SMA, and MMP9, and inhibited TGFβ1-induced fibrotic activation (P<0.01). In addition, CVC attenuated colonic fibrosis in chronic colitis mice. Moreover, CVC significantly promoted autophagy, which contributed to its regulation of inflammation. CVC significantly inhibited inflammation through CCL5/CCR5 signaling without damaging vital organs and suppressed fibrotic activation in chronic colitis, suggesting its great potential to relieve colonic inflammation and fibrosis.

Near-infrared radiation of gold–platinum submicron particle-decorated nonwoven mats enhances wound healing: In vitro and In vivo studies

Because of their biocompatibility and unique optical and electrical properties, Pt nanoparticles (NPs) have been extensively utilized in biomedical applications. However, the use of pure Pt NPs is hindered by the high costs of raw material and absorption at ultraviolet wavelengths. To leverage the benefits of Pt particles while mitigating their drawbacks, we applied electrospinning technology to prepare polyacrylonitrile (PAN) nonwoven mats decorated with gold and platinum submicron particles (Au5Pt3 submicron particle-decorated PAN). We examined the surface morphology, elemental composition, and chemical structure of the resultant Au5Pt3-decorated PAN nonwoven mats by field emission scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, and EDX elemental mapping. When subjected to near-infrared (NIR) illumination, the Au5Pt3-decorated PAN nonwoven mats showed a more stable temperature rise than pure PAN nonwoven mats or Au PAN nonwoven mats. Inductively coupled plasma spectrometry demonstrated that the Au5Pt3-decorated PAN nonwoven mats can release more Pt ions under NIR illumination, reaching concentrations of up to approximately 8 ppm. The Au5Pt3-decorated PAN nonwoven mats exerted positive effects in a wounded mouse model, with or without NIR irradiation: the films did not cause wound adhesion or fibrosis, and excellent skin tissue healing and collagen regeneration were observed. Moreover, when combined with NIR illumination, the Au5Pt3 submicron particle-decorated PAN nonwoven mats more strongly inhibited the growth of Gram-positive and Gram-negative bacteria and more strongly enhanced blood vessel generation, compared with the same mats in the absence of NIR illumination. Regardless of NIR irradiation, the Au5Pt3 submicron particle-decorated PAN nonwoven mats do not show significant damage to the liver or kidney in mice. Overall, treatment with these Au5Pt3 submicron particle-decorated PAN nonwoven mats does not result in toxicity in mice and exerts a positive effect on wound healing when combined with NIR irradiation, with enhanced angiogenesis and collagen regeneration.

Hyphal Als proteins act as CR3 ligands to promote immune responses against Candida albicans

Patients with decreased levels of CD18 (β2 integrins) suffer from life-threatening bacterial and fungal infections. CD11b, the α subunit of integrin CR3 (CD11b/CD18, αMβ2), is essential for mice to fight against systemic Candida albicans infections. Live elongating C. albicans activates CR3 in immune cells. However, the hyphal ligands that activate CR3 are not well defined. Here, we discovered that the C. albicans Als family proteins are recognized by the I domain of CD11b in macrophages. This recognition synergizes with the β-glucan-bound lectin-like domain to activate CR3, thereby promoting Syk signaling and inflammasome activation. Dectin-2 activation serves as the “outside-in signaling” for CR3 activation at the entry site of incompletely sealed phagosomes, where a thick cuff of F-actin forms to strengthen the local interaction. In vitro, CD18 partially contributes to IL-1β release from dendritic cells induced by purified hyphal Als3. In vivo, Als3 is vital for C. albicans clearance in mouse kidneys. These findings uncover a novel family of ligands for the CR3 I domain that promotes fungal clearance.

Mitochondrial GPX4 acetylation is involved in cadmium-induced renal cell ferroptosis

Increasing evidences demonstrate that environmental stressors are important inducers of acute kidney injury (AKI). This study aimed to investigate the impact of exposure to Cd, an environmental stressor, on renal cell ferroptosis. Transcriptomics analyses showed that arachidonic acid (ARA) metabolic pathway was disrupted in Cd-exposed mouse kidneys. Targeted metabolomics showed that renal oxidized ARA metabolites were increased in Cd-exposed mice. Renal 4-HNE, MDA, and ACSL4, were upregulated in Cd-exposed mouse kidneys. Consistent with animal experiments, the in vitro experiments showed that mitochondrial oxidized lipids were elevated in Cd-exposed HK-2 cells. Ultrastructure showed mitochondrial membrane rupture in Cd-exposed mouse kidneys. Mitochondrial cristae were accordingly reduced in Cd-exposed mouse kidneys. Mitochondrial SIRT3, an NAD+-dependent deacetylase that regulates mitochondrial protein stability, was reduced in Cd-exposed mouse kidneys. Subsequently, mitochondrial GPX4 acetylation was elevated and mitochondrial GPX4 protein was reduced in Cd-exposed mouse kidneys. Interestingly, Cd-induced mitochondrial GPX4 acetylation and renal cell ferroptosis were exacerbated in Sirt3−/− mice. Conversely, Cd-induced mitochondrial oxidized lipids were attenuated in nicotinamide mononucleotide (NMN)-pretreated HK-2 cells. Moreover, Cd-evoked mitochondrial GPX4 acetylation and renal cell ferroptosis were alleviated in NMN-pretreated mouse kidneys. These results suggest that mitochondrial GPX4 acetylation, probably caused by SIRT3 downregulation, is involved in Cd-evoked renal cell ferroptosis.

Angiotensin-(1-12): Does It Exist? A Critical Evaluation in Humans, Rats, and Mice.

Angiotensin-(1-12), measured by a self-developed, polyclonal antibody-based radioimmunoassay, has been suggested to act as an alternative precursor of angiotensin II. A more reliable detection method would be liquid chromatography-tandem mass spectrometry. We set up the quantification of human and murine angiotensin-(1-12) by liquid chromatography-tandem mass spectrometry and then used this method to measure angiotensin-(1-12) in human and mouse blood samples, as well as in mouse brain and kidney. We also verified ex vivo angiotensin-(1-12) generation and metabolism in human blood samples incubated at 37 °C. Stabilization of blood in guanidine hydrochloride was chosen for sample collection since this allowed full recovery of spiked angiotensin-(1-12). Angiotensin-(1-12) was undetectable in human blood samples when incubating nonstabilized plasma at 37 °C, while angiotensin-(1-12) added to nonstabilized human plasma disappeared within 10 minutes. Stabilized human blood samples contained angiotensin II, while angiotensin-(1-12) was undetectable. Blood, hearts, and kidneys, but not brains, of wild-type mice and rats contained detectable levels of angiotensin II, while angiotensin-(1-12) was undetectable. In renin knockout mice, all angiotensins, including angiotensin-(1-12), were undetectable at all sites, despite a 50% rise in angiotensinogen. Angiotensin-(1-12) metabolism in human blood plasma was not affected by renin inhibition. Yet, blockade of angiotensin-converting enzyme and aminopeptidase A, but not of chymase, neutral endopeptidase, or prolyl oligopeptidase, prolonged the half-life of angiotensin-(1-12), and angiotensin-converting enzyme inhibition prevented the formation of angiotensin II. We were unable to detect intact angiotensin-(1-12) in humans or mice, either in blood or tissue, suggesting that this metabolite is an unlikely source of endogenous angiotensins.

Ultrastructure expansion microscopy (U-ExM) of mouse and human kidneys for analysis of subcellular structures.

Ultrastructure expansion microscopy (U-ExM) involves the physical magnification of specimens embedded in hydrogels, which allows for super-resolution imaging of subcellular structures using a conventional diffraction-limited microscope. Methods for expansion microscopy exist for several organisms, organs, and cell types, and used to analyze cellular organelles and substructures in nanoscale resolution. Here, we describe a simple step-by-step U-ExM protocol for the expansion, immunostaining, imaging, and analysis of cytoskeletal and organellar structures in kidney tissue. We detail the critical modified steps to optimize isotropic kidney tissue expansion, and preservation of the renal cell structures of interest. We demonstrate the utility of the approach using several markers of renal cell types, centrioles, cilia, the extracellular matrix, and other cytoskeletal elements. Finally, we show that the approach works well on mouse and human kidney samples that were preserved using different fixation and embedding conditions. Overall, this protocol provides a simple and cost-effective approach to analyze both preclinical and clinical renal samples in high detail, using conventional lab supplies and standard widefield or confocal microscopy.

HIF-1α participates in the regulation of S100A16-HRD1-GSK3β/CK1α pathway in renal hypoxia injury

S100 calcium-binding protein 16 (S100A16) is implicated in both chronic kidney disease (CKD) and acute kidney injury (AKI). Previous research has shown that S100A16 contributes to AKI by facilitating the ubiquitylation and degradation of glycogen synthase kinase 3β (GSK3β) and casein kinase 1α (CK1α) through the activation of HMG-CoA reductase degradation protein 1 (HRD1). However, the mechanisms governing S100A16-induced HRD1 activation and the upregulation of S100A16 expression in renal injury are not fully understood. In this study, we observed elevated expression of Hypoxia-inducible Factor 1-alpha (HIF-1α) in the kidneys of mice subjected to ischemia-reperfusion injury (IRI). S100A16 deletion attenuated the increased HIF-1α expression induced by IRI. Using a S100A16 knockout rat renal tubular epithelial cell line (NRK-52E cells), we found that S100A16 knockout effectively mitigated apoptosis during hypoxic reoxygenation (H/R) and cell injury induced by TGF-β1. Our results revealed that H/R injuries increased both protein and mRNA levels of HIF-1α and HRD1 in renal tubular cells. S100A16 knockout reversed the expressions of HIF-1α and HRD1 under H/R conditions. Conversely, S100A16 overexpression in NRK-52E cells elevated HIF-1α and HRD1 levels. HIF-1α overexpression increased HRD1 and β-catenin while decreasing GSK-3β. HIF-1α inhibition restored HRD1 and β-catenin upregulation and GSK-3β downregulation by cellular H/R injury. Notably, Chromatin immunoprecipitation (ChIP) and luciferase reporter assays demonstrated HIF-1α binding signals on the HRD1 promoter, and luciferase reporter gene assays confirmed HIF-1α‘s transcriptional regulation of HRD1. Additionally, we identified Transcription Factor AP-2 Beta (TFAP2B) as the upregulator of S100A16. ChIP and luciferase reporter assays confirmed TFAP2B as a transcription factor for S100A16. In summary, this study identifies TFAP2B as the transcription factor for S100A16 and demonstrates HIF-1α regulation of HRD1 transcription within the S100A16-HRD1-GSK3β/CK1α pathway during renal hypoxia injury. These findings provide crucial insights into the molecular mechanisms of kidney injury, offering potential avenues for therapeutic intervention.

Preparation of NIR-II Polymer Nanoprobe Through Twisted Intramolecular Charge Transfer and Förster Resonance Energy Transfer of NIR-I Dye.

Near-infrared-II (NIR-II) fluorescence imaging is pivotal in biomedical research. Organic probes exhibit high potential in clinical translation, due to advantages such as precise structure design, low toxicity, and post-modifications convenience. In related preparation, enhancement of NIR-II tail emission from NIR-I dyes is an efficient method. In particular, the promotion of twisted intramolecular charge transfer (TICT) of relevant NIR-I dyes is a convenient protocol. However, present TICT-type probes still show disadvantages in relatively low emission, large particle sizes, or limited choice of NIR-I dyes, etc. Herein, the synthesis of stable small-sized polymer NIR-II fluoroprobes (e.g., 7.2nm), integrating TICT and Förster resonance energy transfer process to synergistically enhance the NIR-II emission is reported. Strong enhanced emissions can be obtained from various NIR-I dyes and lanthanide elements (e.g., twelvefold at 1250nm from Nd-DTPA/IR-808 sample). The fluorophore provides high-resolution angiography, with high-contrast imaging on middle cerebral artery occlusion model mice for distinguishing occlusion. The fluorophore can be rapidly excreted from the kidney (urine ≈65% within 4h) in normal mice and exhibits long-term renal retention on acute kidney injury mice, showing potential applications in the prognosis of kidney diseases. This development provides an effective strategy to design and synthesize effective NIR-II fluoroprobes.

An Elastin-like Polypeptide-fusion peptide targeting capsid-tegument interface as an antiviral against cytomegalovirus infection

The tegument protein pp150 of Human Cytomegalovirus (HCMV) is known to be essential for the final stages of virus maturation and mediates its functions by interacting with capsid proteins. Our laboratory has previously identified the critical regions in pp150 important for pp150-capsid interactions and designed peptides similar in sequence to these regions, with a goal to competitively inhibit capsid maturation. Treatment with a specific peptide (PepCR2 or P10) targeted to pp150 conserved region 2 led to a significant reduction in murine CMV (MCMV) growth in cell culture, paving the way for in vivo testing in a mouse model of CMV infection. However, the general pharmacokinetic parameters of peptides, including rapid degradation and limited tissue and cell membrane permeability, pose a challenge to their successful use in vivo. Therefore, we designed a biopolymer-stabilized elastin-like polypeptide (ELP) fusion construct (ELP-P10) to enhance the bioavailability of P10. Antiviral efficacy and cytotoxic effects of ELP-P10 were studied in cell culture, and pharmacokinetics, biodistribution, and antiviral efficacy were studied in a mouse model of CMV infection. ELP-P10 maintained significant antiviral activity in cell culture, and this conjugation significantly enhanced P10 bioavailability in mouse tissues. The fluorescently labeled ELP-P10 accumulated to higher levels in mouse liver and kidneys as compared to the unconjugated P10. Moreover, viral titers from vital organs of MCMV-infected mice indicated a significant reduction of virus load upon ELP-P10 treatment. Therefore, ELP-P10 has the potential to be developed into an effective antiviral against CMV infection.

Up-regulation of long non-coding RNA H19 ameliorates renal tubulointerstitial fibrosis by reducing lipid deposition and inflammatory response through regulation of the microRNA-130a-3p/long-chain acyl-CoA synthetase 1 axis

Long non-coding RNA (lncRNA) H19 is an extensively studied lncRNA that is related to numerous pathological changes. Our previous findings have documented that serum lncRNA H19 levels are decreased in patients with chronic kidney disorder and lncRNA H19 reduction is closely correlated with renal tubulointerstitial fibrosis, an essential step in developing end-stage kidney disease. Nonetheless, the precise function and mechanism of lncRNA H19 in renal tubulointerstitial fibrosis are not fully comprehended. The present work utilized a mouse model of unilateral ureteral obstruction (UUO) and transforming growth factor-β1 (TGF-β1)-stimulated HK-2 cells to investigate the possible role and mechanism of lncRNA H19 in renal tubulointerstitial fibrosis were investigated. Levels of lncRNA H19 decreased in kidneys of mice with UUO and HK-2 cells stimulated with TGF-β1. Up-regulation of lncRNA H19 in mouse kidneys remarkably relieved kidney injury, fibrosis and inflammation triggered by UUO. Moreover, the increase of lncRNA H19 in HK-2 cells reduced epithelial-to-mesenchymal transition (EMT) induced by TGF-β1. Notably, up-regulation of lncRNA H19 reduced lipid accumulation and triacylglycerol content in kidneys of mice with UUO and TGF-β1-stimulated HK-2 cells, accompanied by the up-regulation of long-chain acyl-CoA synthetase 1 (ACSL1). lncRNA H19 was identified as a sponge of microRNA-130a-3p, through which lncRNA H19 modulates the expression of ACSL1. The overexpression of microRNA-130a-3p reversed the lncRNA H19-induced increases in the expression of ACSL1. The suppressive effects of lncRNA H19 overexpression on the EMT, inflammation and lipid accumulation in HK-2 cells were diminished by ACSL1 silencing or microRNA-130a-3p overexpression. Overall, the findings showed that lncRNA H19 ameliorated renal tubulointerstitial fibrosis by reducing lipid deposition via modulation of the microRNA-130a-3p/ACSL1 axis.

Glis2 is an early effector of polycystin signaling and a target for therapy in polycystic kidney disease

Mouse models of autosomal dominant polycystic kidney disease (ADPKD) show that intact primary cilia are required for cyst growth following the inactivation of polycystin-1. The signaling pathways underlying this process, termed cilia-dependent cyst activation (CDCA), remain unknown. Using translating ribosome affinity purification RNASeq on mouse kidneys with polycystin-1 and cilia inactivation before cyst formation, we identify the differential ‘CDCA pattern’ translatome specifically dysregulated in kidney tubule cells destined to form cysts. From this, Glis2 emerges as a candidate functional effector of polycystin signaling and CDCA. In vitro changes in Glis2 expression mirror the polycystin- and cilia-dependent changes observed in kidney tissue, validating Glis2 as a cell culture-based indicator of polycystin function related to cyst formation. Inactivation of Glis2 suppresses polycystic kidney disease in mouse models of ADPKD, and pharmacological targeting of Glis2 with antisense oligonucleotides slows disease progression. Glis2 transcript and protein is a functional target of CDCA and a potential therapeutic target for treating ADPKD.

Rosmarinic acid plus deferasirox inhibits ferroptosis to alleviate crush syndrome-related AKI via Nrf2/Keap1 pathway

BackgroundMyoglobin (Mb) induced death of renal tubular epithelial cells (RTECs) is a major pathological factor in crush syndrome-related acute kidney injury (CS-AKI). It is unclear whether ferroptosis is involved and could be a target for treatment. PurposeThis study aimed to evaluate the potential therapeutic effects of combining the natural small molecule rosemarinic acid (RA) and the iron chelator deferasirox (Dfe) on CS-AKI through inhibition of ferroptosis. MethodsSequencing data were downloaded from the GEO database, and differential expression analysis was performed using the R software limma package. The CS-AKI mouse model was constructed by squeezing the bilateral thighs of mice for 16 h with 1.5 kg weight. TCMK1 and NRK-52E cells were induced with 200 μM Mb and then treated with RA combined with Dfe (Dfe + RA, both were 10 μM). Functional and pathological changes in mouse kidney were evaluated by glomerular filtration rate (GFR) and HE pathology. Immunofluorescence assay was used to detect Mb levels in kidney tissues. The expression levels of ACSL4, GPX4, Keap1, and Nrf2 were analyzed by WB. ResultsWe found that AKI mice in the GSE44925 cohort highly expressed the ferroptosis markers ACSL4 and PTGS2. CS-AKI mice showed a rapid decrease in GFR, up-regulation of ACSL4 expression in kidney tissue, and down-regulation of GPX4 expression, indicating activation of the ferroptosis pathway. Mb was found to deposit in renal tubules, and it has been proven to cause ferroptosis in TCMK1 and NRK-52E cells in vitro. We found that Dfe had a strong iron ion scavenging effect and inhibited ACSL4 expression. RA could disrupt the interaction between Keap1 andNrf2, stabilize Nrf2, and promote its nuclear translocation, thereby exerting antioxidant effects. The combination of Dfe and RA effectively reversed Mb induced ferroptosis in RTECs. ConclusionIn conclusion, we found that RA combined with Dfe attenuated CS-AKI by inhibiting Mb-induced ferroptosis in RTECs via activating the Nrf2/Keap1 pathway.

Long-Term Accumulation, Biological Effects and Toxicity of BSA-Coated Gold Nanoparticles in the Mouse Liver, Spleen, and Kidneys.

Gold nanoparticles are promising candidates as vehicles for drug delivery systems and could be developed into effective anticancer treatments. However, concerns about their safety need to be identified, addressed, and satisfactorily answered. Although gold nanoparticles are considered biocompatible and nontoxic, most of the toxicology evidence originates from in vitro studies, which may not reflect the responses in complex living organisms. We used an animal model to study the long-term effects of 20 nm spherical AuNPs coated with bovine serum albumin. Mice received a 1 mg/kg single intravenous dose of nanoparticles, and the biodistribution and accumulation, as well as the organ changes caused by the nanoparticles, were characterized in the liver, spleen, and kidneys during 120 days. The amount of nanoparticles in the organs remained high at 120 days compared with day 1, showing a 39% reduction in the liver, a 53% increase in the spleen, and a 150% increase in the kidneys. The biological effects of chronic nanoparticle exposure were associated with early inflammatory and fibrotic responses in the organs and were more pronounced in the kidneys, despite a negligible amount of nanoparticles found in renal tissues. Our data suggest, that although AuNPs belong to the safest nanomaterial platforms nowadays, due to their slow tissue elimination leading to long-term accumulation in the biological systems, they may induce toxic responses in the vital organs, and so understanding of their long-term biological impact is important to consider their potential therapeutic applications.

Targeting macrophagic RasGRP1 with catechin hydrate ameliorates sepsis-induced multiorgan dysfunction

BackgroundThe proinflammatory response induced by macrophages plays a crucial role in the development of sepsis and the resulting multiorgan dysfunction. Identifying new regulatory targets for macrophage homeostasis and devising effective treatment strategies remains a significant challenge in contemporary research. PurposeThis study aims to identify new regulatory targets for macrophage homeostasis and develop effective strategies for treating sepsis. Study Design and MethodsMacrophage infiltration in septic patients and in lungs, kidneys, and brains of caecum ligation and puncture (CLP)-induced septic mice was observed using CIBERSORT and immunofluorescence (IF). Upon integrating the MSigDB database and GSE65682 dataset, differently expressed macrophage-associated genes (DEMAGs) were identified. Critical DEMAGs were confirmed through machine learning. The protein level of the critical DEMAG was detected in PBMCs of septic patients, RAW264.7 cells, and mice lungs, kidneys, and brains using ELISA, western blot, immunohistochemistry, and IF. siRNA was applied to investigate the effect of the critical DEMAG in RAW264.7 cells. A natural product library was screened to find a compound targeting the critical DEMAG protein. The binding of compounds and proteins was analyzed through molecular docking, molecular dynamics simulations, CETSA, and MST analysis. The therapeutic efficacy of the compounds against sepsis was then evaluated through in vitro and in vivo experiments. ResultsMacrophage infiltration was inversely correlated with survival in septic patients. The critical differentially expressed molecule RasGRP1 was frequently observed in the PBMCs of septic patients, LPS-induced RAW264.7 cells, and the lungs, kidneys, and brains of septic mice. Silencing RasGRP1 alleviated proinflammatory response and oxidative stress in LPS-treated RAW264.7 cells. Catechin Hydrate (CH) was identified as an inhibitor of RasGRP1, capable of maintaining macrophage homeostasis and mitigating lung, kidney, and brain damage during sepsis. ConclusionThis study demonstrates that RasGRP1, a novel activator of macrophage proinflammatory responses, plays a crucial role in the excessive inflammation and oxidative stress associated with sepsis. CH shows potential for treating sepsis by inhibiting RasGRP1.

Kidney-targeted antioxidant salvianolic acid B nanoparticles restoring lysosome homeostasis for acute kidney injury therapy

Acute kidney injury (AKI) is highly correlated with oxidative stress, and the application of antioxidants is one of the promising treatments. Salvianolic acid B (SAB) is a natural polyphenol with powerful antioxidant effects. Due to its inherent characteristic of inferior bioavailability, its clinical application is impeded. In this study, small SAB-incorporated nanoparticles (SFA) were synthesized via the self-assembly of SAB, ferric ions, and bovine serum albumin (BSA). Apart from antioxidant activity, the SFA nanoparticles were found to efficiently restore lysosome dysfunction induced by reactive oxygen species (ROS) in human kidney proximal tubular epithelial HK-2 cells. The small size and BSA incorporation make the SFA nanoparticles to be promising AKI-targeting nanoparticles. They are rapidly accumulated and long-term retained in injured kidneys of glycerol-induced AKI mice, especially in the proximal tubules which are the key lesion location during AKI. In vivo studies indicate that SFA nanoparticles show a superior protective effect compared with the free drug by suppressing oxidative stress and maintaining lysosome homeostasis indicated by enhanced heme oxygenase-1 (HO-1) expression and restored cathepsin B (CTSB) activity, respectively. In summary, this study develops a delivery system for the antioxidant SAB enhancing local delivery and offering an additional lysosome restoring mechanism for AKI therapy.

Long Non-coding RNA Neat1, NLRP3 Inflammasome, and Acute Kidney Injury.

Acute kidney injury (AKI) is common in hospitalized patients and is associated with high mortality. Inflammation plays a key role in the pathophysiology of AKI. Long non-coding RNAs (lncRNAs) are increasingly recognized as regulators of the inflammatory and immune response, but its role in AKI remains unclear. We explored the role of lncRNA Neat1 in (1) a cross-sectional and a longitudinal cohort of AKI in human; (2) three murine models of septic and aseptic AKI and (3) cultured C1.1 mouse kidney tubular cells. In human, hospitalized patients with AKI (n=66) demonstrated significantly increased lncRNA Neat1 levels in urinary sediment cells and buffy coat versus control participants (n=152) from a primary care clinic; and among 6 kidney transplant recipients, Neat1 levels were highest immediately after transplant surgery followed by a prompt decline to normal levels in parallel with recovery of kidney function. In mice with AKI induced by sepsis (via LPS injection or cecal ligation and puncture) and renal ischemia-reperfusion, kidney tubular Neat1 was increased versus sham-operated mice. Knockdown of Neat1 in the kidney using short hairpin RNA preserved kidney function, suppressed overexpression of the AKI biomarker NGAL, leukocyte infiltration and both intrarenal and systemic inflammatory cytokines IL-6, CCL-2 and IL-1β. In LPS-treated C1.1 cells, Neat1 was overexpressed via TLR4/NF-κB signaling, and translocated from the cell nucleus into the cytoplasm where it promoted activation of NLRP3 inflammasomes via binding with the scaffold protein Rack1. Silencing Neat1 ameliorated LPS-induced cell inflammation, whereas its overexpression upregulated IL-6 and CCL-2 expression even without LPS stimulation. Our findings demonstrate a pathogenic role of Neat1 induction in human and mice during AKI with alleviation of kidney injury in 3 experimental models of septic and aseptic AKI after knockdown of Neat1. LPS/TLR4-induced Neat1 overexpression in tubular epithelial cells increases the inflammatory response by binding with the scaffold protein, Rack1, to activate NLRP3 inflammasomes.

Porous Se@SiO2 nanocomposites play a potential inhibition role in hyperoxaluria associated kidney stone by exerting antioxidant effects.

Nephrolithiasis seriously affects people's health with increasing prevalence and high recurrence rates. However, there is still a lack of effective interventions for the clinical prevention of kidney stones. Hyperoxaluria-induced renal tubular epithelial cell (TEC) injury is a known key factor in kidney stone formation. Thus, developing new drugs to inhibit the hyperoxaluria-induced TEC injury may be the best way. We synthesized the Se@SiO2 nanocomposites as described in Zhu's study. The size and morphology of the Se@SiO2 nanocomposites were captured by transmission electron microscopy. Cell viability was measured by a Cell Counting Kit-8 (CCK-8) assay. The mice were randomly divided into the following four groups: (I) the control group (n=6); (II) the Se@SiO2 group (n=6); (III) the glyoxylic acid monohydrate (GAM) group; and (IV) the GAM + Se@SiO2 group (n=6). The concentration of Se in the mice was quantified using inductively coupled plasma atomic emission spectroscopy. The CCK-8 assays showed that Se@SiO2 nanocomposites had almost no obvious cytotoxicity on the Transformed C3H Mouse Kidney-1 (TCMK-1) cell. The mice kidney Se concentration levels in the Se@SiO2 groups (Se@SiO2 6.905±0.074 mg/kg; GAM + Se@SiO2 7.673±2.85 mg/kg) (n=6) were significantly higher than those in the control group (Control 0.727±0.072 mg/kg; GAM 0.747±0.074 mg/kg) (n=6). The Se@SiO2 nanocomposites reduced kidney injury, calcium oxalate crystal deposition, and the osteoblastic-associated proteins in the hyperoxaluria mice models. Se@SiO2 nanocomposites appear to protect renal TECs from hyperoxaluria by reducing reactive oxygen species production, suggesting the potential role of preventing kidney stone formation and recurrence.