Renal Inflammation Research Articles

PPAR gamma and PGC-1alpha activators protect against diabetic nephropathy by suppressing the inflammation and NF-kappaB activation.

Inflammation plays a critical role in the progression of diabetic nephropathy. Peroxisome proliferator-activated receptor gamma (PPARγ) and its coactivator PPARγ coactivator-1 alpha (PGC-1α) enhance mitochondrial biogenesis and cellular energy metabolism but inhibit inflammation. However, the molecular mechanism through which these two proteins cooperate in the kidney remains unclear. The aim of the present study was to investigate this mechanism. HK-2 human proximal tubular cells were stimulated by inflammatory factors, the expression of PPARγ and PGC-1α were determined via reverse transcription-quantitative polymerase chain reaction (PCR) and western blotting (WB), and DNA binding capacity was measured by an EMSA. Furthermore, db/db mice were used to establish a diabetic nephropathy model and were administered PPARγ and PGC-1α activators. Kidney injury was evaluated microscopically, and the inflammatory response was assessed via WB, immunohistochemistry and immunofluorescence staining. Besides, HK-2 cells were stimulated by high glucose and inflammatory factors with and without ZLN005 treatment, the expression of PPARγ, PGC-1α, p-p65 and p65 were determined via qPCR and WB. Our results revealed that both TNF-α and IL-1β significantly decreased PPARγ and PGC-1 expression in vitro. Cytokines obviously decreased PPARγ DNA binding capacity. Moreover, we detected rapid activation of the NF-κB pathway in the presence of TNF-α or IL-1β. PPARγ and PGC-1α activators effectively protected against diabetic nephropathy and suppressed NF-κB expression both in db/db mice and HK-2 cells. PPARγ and its coactivator PGC-1α actively participate in protecting against renal inflammation by regulating the NF-κB pathway, which highlights their potential as therapeutic targets for renal diseases.

The negative feedback loop of NF-κB/miR-202-5p/HMGB2 attenuates sepsis induced acute kidney injury

Sepsis represents a primary cause of acute kidney injury (AKI), yet the underlying mechanisms of septic AKI remain poorly understood. Thus, there exists an urgent need for a deeper understanding of its underlying mechanisms and the development of effective therapeutic strategies. Our study reveals a notable induction in microRNA-202-5p (miR-202-5p) levels within renal tubular cells in septic AKI both in vivo and in vitro models. Treatment of renal tubular cells with LPS induced NF-κB activation, which was linked to the induction of miR-202-5p. ChIP assays confirmed NF-κB binding to the miR-202-5p gene promoter upon LPS stimulation. Functionally, miR-202-5p mimics attenuated tubular cell death, kidney injury, and intra-renal inflammatory cytokine production, whereas inhibition of miR-202-5p conferred injurious effects in septic AKI. Notably, miR-202-5p suppressed the expression of High Mobility Group Box 2 (HMGB2) in both in vitro and in vivo septic AKI models. Luciferase microRNA target assays further validated HMGB2 as a direct target of miR-202-5p. Knockdown of HMGB2 inhibits LPS-induced NF-κB activation in septic AKI, as evidenced by HMGB2 siRNA transfection significantly inhibited the nuclear translocation of NF-κB. Together, these findings elucidate the NF-κB/miR-202-5p/HMGB2 negative feedback loop which can attenuate kidney injury by inhibiting renal inflammation in septic AKI. Our findings open new avenues for developing targeted therapies to manage septic AKI effectively.

The RNA binding protein Arid5a drives IL-17-dependent autoantibody-induced glomerulonephritis.

Autoantibody-mediated glomerulonephritis (AGN) arises from dysregulated renal inflammation, with urgent need for improved treatments. IL-17 is implicated in AGN and drives pathology in a kidney-intrinsic manner via renal tubular epithelial cells (RTECs). Nonetheless, downstream signaling mechanisms provoking kidney pathology are poorly understood. A noncanonical RNA binding protein (RBP), Arid5a, was upregulated in human and mouse AGN. Arid5a-/- mice were refractory to AGN, with attenuated myeloid infiltration and impaired expression of IL-17-dependent cytokines and transcription factors (C/EBPβ, C/EBPδ). Transcriptome-wide RIP-Seq revealed that Arid5a inducibly interacts with conventional IL-17 target mRNAs, including CEBPB and CEBPD. Unexpectedly, many Arid5a RNA targets corresponded to translational regulation and RNA processing pathways, including rRNAs. Indeed, global protein synthesis was repressed in Arid5a-deficient cells, and C/EBPs were controlled at the level of protein rather than RNA accumulation. IL-17 prompted Arid5a nuclear export and association with 18S rRNA, a 40S ribosome constituent. Accordingly, IL-17-dependent renal autoimmunity is driven by Arid5a at the level of ribosome interactions and translation.

P099 EXERCISE TRAINING FURTHER ATTENUATES BLOOD PRESSURE VARIABILITY AND RENAL DAMAGE IN HYDROCHLOROTHIAZIDE TREATED-HYPERTENSIVE AND POSTMENOPAUSAL RATS

Background and Objective: Considering that blood pressure variability (BPV) has been associated with damage to target organs such as the kidney, this study aimed to investigate the effects of hydrochlorothiazide (HCTZ) combined with exercise training (CET) on BPV, as well as renal tissue morphology, function, inflammation, and oxidative stress. Methods: Female spontaneously hypertensive rats (SHR) were divided into 4 ovariectomized groups (n=5-6/group): sedentary (OS), sedentary + HCTZ (OSH), trained (OT), and trained + HCTZ (OTH). Both HCTZ (3 mg/kg) and CET (3 days/week) were administered for 8 weeks. Blood pressure was directly recorded for BPV analysis. Results: Renal function, morphology, inflammation and oxidative stress were assessed. The OSH, OT, and OTH groups had lower systolic BP (OSH: 189±13; OT: 179±5; OTH: 174±15 mmHg) compared to the OS group (208±15 mmHg). Only the combination of the drug with CET promoted a reduction in BPV variance. The HCTZ-treated groups showed lower plasma creatinine levels and increased creatinine clearance compared to the OS group. Treated groups showed a reduction in fields of 51–100% of interstitial tubule fibrosis when compared to the OS group; and the OTH group also showed reduction in fields in the range of 26–50% vs. other groups. The HCTZ-treated groups showed a reduction in protein oxidation. Renal catalase and IL10/TNF-alpha ratio were increased in the OTH group. Positive correlations were obtained between SBP variance and SBP (r=0.72), plasma creatinine (r=0.58), and levels of TNF-α (r=0.69), hydrogen peroxide (r=0.61), and protein oxidation (r=0.66) in renal tissue. Conclusions: Our results highlight the enhanced efficacy of the combination of HCTZ and CET compared to the use of either drug alone in the model studied. This combination effectively reduced BPV, resulting in beneficial changes in renal inflammatory and redox profiles, inducing morphological and functional benefits in hypertensive ovariectomized rats. Financial support: FAPESP (2022/04050-1), CNPq, CAPES-PROSUP, UNINOVE.

MicroRNA-223 alleviates inflammatory response in renal ischemia-reperfusion injury by targeting NLRP3.

We investigated the potential correlation between miR-223 and NAcHT, LRR, and PYd domain-containing protein 3 (NLRP3) in the context of renal ischemia-reperfusion injury (RIRI), which is a leading cause of acute renal failure with significant mortality rates. Additionally, miR-223 has been implicated in renal inflammation, further highlighting its relevance to this study. C57BL/6 male mice were used as RIRI models. After successful modeling, pathological examinations and serum creatinine and miR-223 levels were tested. Pro-inflammatory cytokine (IL-1β, IL-6, IL-8, NLPR3, TLR4) expression was detected in mice by western blot (kidney tissue) and enzyme-linked immunosorbent assay (serum). HK-2 cells were used for in vitro experiments. A hypoxia/reoxygenation (H/R) model was used, and miR-223 and pro-inflammatory cytokine levels were detected using PCR and western blot assays, respectively. A dual-luciferase reporter assay was conducted to confirm the binding of miR-223 to NLPR3. Next, NLRP3 was knocked down to determine whether the anti-inflammatory function of miR-223 is dependent on NLRP3. MiR-223 expression was lower in RIRI mice than in the sham operation group. The level of miR-223 negatively correlated with serum creatinine levels and the severity of tubule injury. Increased proinflammatory cytokine levels in RIRI mice were observed. In vitro, miR-223 alleviated the inflammatory response in H/R treated cells by inhibiting proinflammatory cytokines. Dual-luciferase reporter and western blot assays confirmed the binding of miR-223 to NLRP3. NLRP3 knockdown reversed the anti-inflammatory effects of miR-223 in HK-2 cells. MiR-223 plays an anti-inflammatory role in RIRI by targeting NLRP3 to repress pro-inflammatory factors.

Abstract 36: Ablation of T-Lymphocyte β-Arrestins Reduces Inflammation and Increases Salt Retention in the Absence of Blood Pressure Changes Following Angiotensin II Infusion

Introduction: T-cells contribute to hypertension (HT) development. Among several G-protein coupled receptors regulating T-cell function, it has been hypothesized that some subpopulations use the angiotensin II (ANG II) type 1 receptor (AT 1 R) to modulate immune responses in HT. Selective ablation of AT 1 Rs in T-cells paradoxically increases hypertensive end-organ damage (EOD). While AT 1 Rs typically induces classical G-protein signaling, recent studies have uncovered a protective signaling cascade via β-arrestin ( ARRB ) proteins. We hypothesize that T-cell ARRB s mediate an anti-hypertensive and anti-inflammatory role in response to ANG II, decreasing EOD in HT. Methods: Breeding CD4-Cre mice with Arrb1 -Flox or Arrb2 -Flox mice generated lines with T-cell-specific deficiency of Arrb1 or Arrb2 genes. Hypertensive conditions modeling kidney damage consisted of unilateral nephrectomy, 4% salt diet, and continuous infusion of 1 mg/kg/min ANG II (UNX/HSD/ANG). Age/sex-matched Cre - littermates were used as controls (WT). Blood pressure (BP) was measured at baseline and for the following three weeks using radiotelemetry. Results: At baseline, there were no significant differences in systolic BP between groups (WT:124.1±8.0 mmHg; CD4 Arrb1-null :125.4±8.1; CD4 Arrb2-null :128.7±3.1; p =0.37; n=12/10/8). Three weeks of UNX/HSD/ANG equally increased systolic BP in all groups (WT:178.0±14.0 mmHg; CD4 Arrb1-null :174.8±26.3; CD4 Arrb2-null :179.9±11.1; p =0.86; n=7/9/7). Despite similar BPs, CD4 Arrb2-null mice demonstrated less renal inflammation than WT after four weeks of UNX/HSD/ANG, with a reduction in interleukin-1α protein (3.8±3.2 vs. 8.3±2.8 p <0.05; n=4/6) and a trend towards decreased tumor necrosis factor-α transcript (0.63-fold change vs. 1.9, p =0.051; n=10/8). Furthermore, CD4 Arrb1-null mice increased 24-hour voluntary water intake compared to WT (15.7±3.4 mL vs. 12.2±1.6; p <0.05; n=12/7), and 24-hour urine output (10.0±3.7 mL/d vs. 6.8±1.5; p <0.05; n=11/8). However, there was no difference in sodium excretion during this period (1.9±0.5 eq/d vs. 1.7±0.1; p =0.14; n=11/7). Interestingly, 4 hours after intraperitoneal saline injection, CD4 Arrb1-null mice excreted significantly less sodium compared to WT (5.6±3.5% vs . 31.4±10.6%; p <0.05; n=4/5). Conclusion: Contrary to our hypothesis, these data suggest that T-cell Arrb s do not protect against the hypertensive response to ANG II, but instead play a complicated role in the modulation of hydromineral balance and inflammation.

Abstract 71: Analysis of First Morning Urine Transcriptomes in Normotensive and Hypertensive Patients Identify Upregulated Inflammatory and Signaling Pathways Associated with Hypertension

Introduction: Hypertension (HTN) remains poorly controlled at the population level. The kidney plays a prominent role in HTN, but the molecular mechanisms are unclear. We enrolled a cohort of patients with HTN, and controls, to study new molecular signatures in the transcriptome of cells shed in first morning urine samples. Methods: We collected demographics, 24-h and first-morning urine collections from 80 non-diabetic patients aged >40 with HTN and 20 controls (no HTN). Descriptive variables were summarized. Gene expression was assessed after Next Gen sequencing of mRNA obtained from cells pulled down from first-morning urine and assessed for differentially expressed genes (DEG) (<1 Log2 fold-, p<0.05 FDR) by the Wilcoxon Rank-Sum test. Pathway analysis for DEGs was performed with an in-house Python script that highlights genes associated with cardiovascular diseases including HTN, CKD, type 2 diabetes, inflammation, surface proteins (GPCR, transporters, etc), and the kinome. Results: Cohort characteristics are shown in Table 1. After QC, full transcriptomes were analyzed for 11 control and 34 HTN subjects. 20,800 transcripts were identified (including known genes, ORFs and LncRNAs) and compared between groups. 916 DEGs (FDR p<0.05) were identified: 911 genes up- and 5 down-regulated. In HTN subjects, there was overrepresentation of genes in inflammatory signaling pathways (12.5% of all DEGs) including those in IFN-alpha, IFN-gamma, Interleukin (IL)9, IL17 and IL18, and innate immunity. 15 genes, associated with HTN, and 45, associated with type-2 diabetes, at the genome-wide level were up-regulated in the HTN cohort including (LINC00592, ADRA1D, SLC39A12, WNT3A, RXFP2, DEFB136, PDE3A, OPRM1, RIBC2, GRIN2A, CHEK2, HOXA3, CCDC149, COL4A2). Transcripts for major apical nephron NaCl transporters were not significantly different, however, SLC12A5 (K/Cl cotransporter KCC2) and the voltage gated K channels (KCNE1, KCNE2) were up-regulated in HTN patients. Conclusions: We conclude that analysis of transcriptomes of cells shed in first morning urine of control and HTN patients allows for the identification of DEG. These data align well with our previous finding indicating that renal inflammation is associated with difficult-to-control hypertension, and as shown here, are also associated with HTN in general. This method allows for discovery of new inflammatory pathways that could render additional treatments for HTN or CKD.

Abstract P338: Impaired Endothelial-Dependent Vasorelaxation and Myogenic Response in Renal Afferent Arterioles of Diabetic mice: Role of Endothelial NOX1, and New Gene Pathways.

Diabetes increases the risk of cardiovascular disease and hypertension, in part, by decreasing arterial vasodilation through decreased NO bioavailability and increased superoxide. In the kidney, type 1 diabetes induces a decrease in renal filtration, proteinuria, inflammation, and fibrosis, increasing the incidence of kidney disease. In diabetic rats and rabbits, prone to renal disease, diabetes blunts acetylcholine (Ach)-induced vasorelaxation of afferent arterioles, in part, by enhancing endothelial superoxide. However, it is unclear whether diabetes affects afferent arteriole vasodilation and myogenic response in mice. We hypothesize that diabetes increases endothelial NOX1 mediated superoxide production in mouse afferent arterioles, decreasing Ach-induced vasodilation. We dissected and perfused afferent arterioles from male diabetic Akita mice 12-14 weeks of age and measured the effect Ach (10 -7 -10 -5 M) on luminal diameter after pre-constriction with norepinephrine. Diabetic Akita mice had a largely reduced Ach-induced dilation at all doses of Ach (80±6% average inhibition in dilation, p<0.025, n=6). To study the role of NOX1, we used the inhibitor ML171 (5µM). When added to the endothelial lumen, NOX1 inhibition completely restored Ach-induced dilation of diabetic Akita mice, which was not different from WT controls. In Control C57 mice, ML171 did not change Ach-induced dilation in Aff-Art (n=6). We then examined the myogenic response in diabetic mice by measuring lumen diameter after step increases in perfusion pressure (60-140 mmHg). Afferent arterioles of diabetic Akita mice did not constrict when pressure was increased, even at 140 mmHg, whereas WT mice showed normal myogenic response (delta constriction 60-140 mmHg WT: 2.15±0.41 vs Akita: 0.37±0.32 µm, WT p<0.01 from baseline, Akita n.s from baseline). To understand the mechanisms behind these effects we performed RNAseq in manually micro-dissected afferent arterioles from 12-week-old Akita and WT mice. Bioinformatics analysis showed 530 DEGs (FDR pAdj<0.05, n=6). Most of the DEGs are involved in endothelial cell function/metabolism, smooth muscle cell contractility, activated inflammatory pathways, and free radical/NO production. We conclude that early diabetes has a large effect on renal afferent arteriole reactivity by affecting the expression of hundreds of genes. These effects are likely involved in hypertension and kidney damage progression in type 1 diabetes.

Integrating transcriptomics, metabolomics, and network pharmacology to investigate multi-target effects of Sporoderm-broken spores of Ganoderma lucidum on improving HFD-induced diabetic nephropathy rats

Diabetes mellitus (DM) is a major metabolic disease endangering global health, with diabetic nephropathy (DN) as a primary complication lacking curative therapy. Sporoderm-broken spores of Ganoderma lucidum (GLP), an herbal medicine, has been used for the treatment of metabolic disorders. In this study, DN was induced in Sprague-Dawley rats using streptozotocin (STZ) and a high-fat diet (HFD), and the protective mechanisms of GLP were investigated through transcriptomic, metabolomic, and network pharmacology analyses. Our results demonstrated that GLP intervention ameliorated renal damage and inflammation levels in DN rats. Integrative metabolomic and transcriptomic analysis revealed that GLP treatment modulated glucose and cellular energy metabolisms by regulating relevant genes. GLP significantly suppressed the inflammations by impacting glucose and energy metabolism-related gene expression (Igfbp1 and Angptl4) and enhanced metabolic biomarkers of 4-Aminocatechol. In addition, network pharmacology analysis further indicated that GLP may efficiently alleviate DN via immune-related pathways. In conclusion, this study provides supportive evidence of the anti-inflammatory effects of GLP supplements, highlighting their potential for promising clinical applications in treating diabetic nephropathy.

Abstract MP33: A20 in the Kidney Epithelium Attenuates Angiotensin II-induced Hypertension by Constraining Renal Tubular NHE3 Expression

Whereas the ubiquitin editor A20 limits NF-κB-mediated signaling in myeloid leukocytes, the functions of A20 in renal epithelial cells during hypertension have not been described. We recently found that A20 in the kidney tubule ameliorates hypertension and cardiac hypertrophy induced by chronic angiotensin (Ang) II infusion (500ng/kg/min) in mice. Here we report that following 3 weeks of hypertension, the kidneys of mice with tubular deletion of A20 in the kidney epithelium (“A20 iKKO” = A20 flox/flox Pax8-rtTA TetO-Cre + ) have augmented protein expression of the proximal tubular sodium transporter NHE3 (1.5±0.1 vs. 1.0±0.1; p <0.01) but similar levels of ENaC subunit expression in the collecting tubule ( p =NS for all 3 subunits) vs wild-type (WT) controls. Moreover, kidneys from A20 iKKO mice have upregulated mRNA levels for the T cell chemokine CCL5 (2.4±0.3 vs. 1.0±0.3; p <0.01) and higher proportions of effector memory CD8 + T cells (51.2±2.3 vs. 39.3±2.9 % of CD8 + ; p =0.013) compared to WTs despite similar numbers of effector memory T cells in the spleen ( p =NS). To examine whether A20 in the kidney attenuates hypertension by constraining tubular NHE3 expression, we bred A20 iKKO mice with an NHE3 flox/flox line, thereby generating mice with double A20 and NHE3 deletion in the kidney tubule (“Dual KKO”) mice. At baseline, kidneys from Dual KKO mice showed robust reductions in mRNA for A20 (0.5±0.1 vs. 1.0±0.1; p =0.022) and NHE3 (0.2±0.05 vs. 1.0±0.15; p =0.002) compared to WT littermates. During the first ten days of Ang II infusion, mean arterial pressures (MAPs) in the Dual KKO mice were lower than the MAPs previously recorded in our A20 iKKO cohort (129±3 vs. 152±4 mmHg; p <0.01). Moreover, during 3 weeks of Ang II infusion, Dual KKO and WT mice maintained similar MAPs (145±7 vs. 149±13 mmHg; p =0.78), and heart weight to body weight ratios (5.9±0.3 vs. 5.5±0.2 mg/g; p =0.37) in concomitant measurements. Thus, A20 in the kidney tubule blunts the chronic hypertensive response by curtailing NHE3 expression. Our data further suggest that A20 in the nephron can blunt renal inflammation without altering systemic T cell immunity. Stimulating the A20 signaling pathway in the kidney may thus attenuate NHE3-dependent hypertension without conferring attendant risks of global immunosuppression.

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<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.

Salinomycin, a potent inhibitor of XOD and URAT1, ameliorates hyperuricemic nephropathy by activating NRF2, modulating the gut microbiota, and promoting SCFA production

Long-term hyperuricemia can induce kidney damage, clinically referred to as hyperuricemic nephropathy (HN), which is characterized by renal fibrosis, inflammation, and oxidative stress. However, currently used uric acid-lowering drugs are not capable of protecting the kidneys from damage. Therefore, uric acid-lowering drugs that can also protect the kidneys are urgently needed. In this study, we first discovered that salinomycin, an antibiotic, can regulate uric acid homeostasis and ameliorate kidney damage in mice with HN. Mechanistically, salinomycin inhibited serum and hepatic xanthine oxidase (XOD) activities and downregulated renal urate transporter 1 (URAT1) expression and transport activity, thus exerting uric acid-lowering effects in mice with HN. Furthermore, we found that salinomycin promoted p-NRF2 Ser40 expression, resulting in increased nuclear translocation of NRF2 and activation of NRF2. More importantly, salinomycin affected the gut microbiota and promoted the generation of short-chain fatty acids (SCFAs) in mice with HN. In conclusion, our results revealed that salinomycin maintains uric acid homeostasis and alleviates kidney injury in mice with HN by multiple mechanisms, suggesting that salinomycin might be a desirable candidate for HN treatment in the clinic.

Comparison of the effects of Liraglutide, Tirzepatide, and Retatrutide on diabetic kidney disease in db/db mice.

To assess and compare the therapeutic efficacy of Liraglutide, Tirzepatide, and Retatrutide in treating diabetic kidney disease (DKD) in db/db mice. Db/db mice were administered intraperitoneal injections of Liraglutide (10 nmol/kg), Tirzepatide (10 nmol/kg), and Retatrutide (10 nmol/kg) for 10 weeks. Subsequently, we assessed the effectiveness of these three drugs in controlling blood glucose levels, reducing weight, and improving serum biochemical indicators and DKD. Additionally, we measured and compared the renal inflammation and fibrosis indexes. Meanwhile, the content of intestinal metabolite butyrate was compared to reflect the regulatory effects of these three drugs on gut microbiota. Retatrutide demonstrated superior effectiveness in reducing weight and improving renal function in db/db mice compared to Liraglutide and Tirzepatide. Additionally, it markedly suppressed the expression of pro-inflammatory cytokines (TNF-α, caspase-1, and NLRP3) and pro-fibrotic factors (fibronectin, α-SMA, and collagen I) in the kidneys of mice. Furthermore, Retatrutide substantially enhanced liver function, reduced triglyceride levels, cholesterol levels, low-density lipoprotein cholesterol, elevated high-density lipoprotein cholesterol, and increased the content of intestinal metabolite butyrate in db/db mice when compared to the other two drugs. Unfortunately, despite its ability to lower blood glucose levels, Retatrutide did not outperform the other two drugs. In contrast, Tirzepatide exhibited better effects on lowering blood glucose, weight loss, lipid reduction, and improvement of DKD compared to Liraglutide. Retatrutide and Tirzepatide were significantly effective in improving DKD, controlling blood glucose and body weight. Retatrutide was the most effective in improving DKD and body weight, while Tirzepatide was the most effective in controlling blood glucose. Inhibiting the expression of inflammatory factors and fibrosis mediators and regulating intestinal microbiota may be the potential mechanisms of these two drugs to delay the progression of DKD.

Serum and urinary monocyte chemoattractant protein-1 as markers of inflammation and renal damage in dogs with naturally occurring leishmaniosis

BackgroundRenal disease in canine leishmaniosis is of great importance owing to increased risk of mortality. In human visceral leishmaniosis, monocyte chemoattractant protein-1 (MCP-1) has been used as a marker of renal damage and inflammation. The purpose of this study was first to determine the serum MCP-1 and urinary MCP-1-to-creatinine ratio (uMCP-1/Cr) in healthy dogs and dogs with leishmaniosis at diagnosis, and second to determine whether these markers can differentiate disease severity at diagnosis.MethodsIn total, 19 healthy seronegative dogs and 38 dogs with leishmaniosis were included in the study. Dogs with leishmaniosis were classified as LeishVet clinical staging and as International Renal Interest Society (IRIS) staging. Serum and urinary MCP-1 concentrations were measured with an enzyme-linked immunosorbent assay. A receiver operating characteristic (ROC) curve determined disease severity at diagnosis between two LeishVet groups (Stage II versus stage III and IV).ResultsDogs in Leishvet stages IIb, III, and IV had a median serum MCP-1 and uMCP-1/Cr concentration higher than healthy dogs (P < 0.0001). No statistical differences were found in serum MCP-1 and uMCP-1/Cr between dogs in LeishVet stage IIa and healthy dogs. The dogs in LeishVet stage IV had significantly higher serum MCP-1 and uMCP-1/Cr compared with the dogs in LeishVet stage IIa (P < 0.0001). Serum MCP-1 and uMCP-1 were significantly higher in dogs in IRIS stage I and II + III + IV compared with healthy dogs. Dogs stage II + III + IV of IRIS had a significantly higher serum MCP-1 compared with dogs in IRIS stage I (P < 0.0001). The area under the ROC curve for serum MCP-1 was 0.78 [95% confidence interval (CI) 0.64–0.93] and for uMCP-1/Cr it was 0.86 (95% CI, 0.74–0.99). The optimal cutoff value for serum MCP-1 and uMCP-1/Cr was 336.85 pg/ml (sensitivity of 79% and specificity of 68%) and 6.89 × 10−7 (sensitivity of 84% and specificity of 79%), respectively.ConclusionsSerum MCP-1 and uMCP-1/Cr are increased in dogs with leishmaniosis compared with healthy dogs, suggesting the presence of inflammation and renal injury. Serum MCP-1 and uMCP-1/Cr were more elevated in the advanced stages of the disease compared with the moderate stages and, therefore, can be markers of the severity of the disease process.Graphical

ST2 + T-Regulatory Cells in Renal Inflammation and Fibrosis after Ischemic Kidney Injury.

Inflammation is a major cause of kidney injury. The Interleukin (IL)-1 family cytokine IL-33 is released from damaged cells and modulates the immune response through its receptor ST2 expressed on many cell types, including regulatory T-cells (Tregs). While a proinflammatory role of IL-33 has been proposed, exogenous IL-33 expanded Tregs and suppressed renal inflammation. However, the contribution of endogenous IL-33/ST2 for the role of Tregs in the resolution of kidney injury has not been investigated. We used murine renal ischemia-reperfusion injury and kidney organoids to delineate the role of the ST2 and amphiregulin (AREG) specifically in Treg cells using targeted deletion. Bulk and single-cell RNA sequencing was performed on flow-sorted Tregs from spleen and CD4 T-cells from post-ischemic kidneys respectively. The protective role of ST2-sufficient Tregs was analyzed using a novel co-culture system of syngeneic kidney organoids and Treg cells under hypoxic conditions. Bulk RNA-sequencing of splenic and single-cell-RNA-sequencing of kidney T-cells showed that ST2+ Tregs are enriched for genes related to Treg proliferation and function. Genes for reparative factors such as AREG were also enriched in ST2+ Tregs. Treg-specific deletion of ST2 or AREG exacerbated kidney injury and fibrosis in the unilateral ischemia reperfusion injury model. In co-culture studies, WT but not ST2-deficient Tregs preserved the hypoxia-induced loss of kidney-organoid viability, which was restored by AREG supplementation. Our study identified the role of the IL-33/ST2 pathway in Tregs for resolution of kidney injury. The transcriptome of ST2+ Tregs was enriched for reparative factors including AREG. Lack of ST2 or AREG in Tregs worsened kidney injury. Tregs protected kidney organoids from hypoxia in ST2 and AREG-dependent manner. Thus Treg-based approaches could be of benefit for resolution of renal injury.

Pharmacokinetic profiling of ZCL-278, a cdc42 inhibitor, and its effectiveness against chronic kidney disease

ZCL-278 is a selective small molecule specifically inhibiting the Cdc42-intersectin interaction, yet its in-vivo pharmacokinetic and pharmacodynamic properties against renal diseases had not been determined. Thus, our study explored the absorption, distribution and excretion of ZCL-278 as well as its pharmacological efficacy against chronic kidney disease (CKD). With the optimized detection method, absolute oral bioavailability of ZCL-278 was determined as 10.99 % in male and 17.34 % in female rats. ZCL-278 was rapidly and abundantly distributed in various tissues, especially the kidney and heart, while few excreted through urine and feces. In the adenine-induced CKD mice, the increased plasma creatinine and urea, the decreased body weight as well as the renal pathological alterations, including vacuolization of renal tubular epithelial cells, granular degeneration, cell flattening, luminal dilation, and cylindruria, were significantly ameliorated after ZCL-278 administration. Moreover, ZCL-278 could also reverse the increased intensities of renal inflammation and fibrosis in the CKD mice. These results clarified the pharmacokinetics of ZCL-278 in rats and preliminarily indicated that ZCL-278 has favorable pharmacodynamic properties for CKD primed for lead development and optimization, warranting further drug development.

Mineralocorticoid receptor (MR) antagonist eplerenone and MR modulator balcinrenone prevent renal extracellular matrix remodeling and inflammation via the MR/proteoglycan/TLR4 pathway.

Excessive activation of the mineralocorticoid receptor (MR) is implicated in cardiovascular and renal disease. Decreasing MR activation with MR antagonists (MRA) is effective to slow chronic kidney disease (CKD) progression and its cardiovascular comorbidities in animal models and patients. The present study evaluates the effects of the MR modulator balcinrenone and the MRA eplerenone on kidney damage in a metabolic CKD mouse model combining nephron reduction and a 60% high-fat diet. Balcinrenone and eplerenone prevented the progression of renal damages, extracellular matrix remodeling and inflammation to a similar extent. We identified a novel mechanism linking MR activation to the renal proteoglycan deposition and inflammation via the TLR4 pathway activation. Balcinrenone and eplerenone similarly blunted this pathway activation.

Canonical effects of cytokines on glomerulonephritis: Anew outlook in nephrology.

Glomerulonephritis (GN) is an important cause of renal inflammation resulting from kidney-targeted adaptive and innate immune responses and consequent glomerular damage. Given the lack of autoantibodies, immune complexes, or the infiltrating immune cells in some forms of GN, for example, focal segmental glomerulosclerosis and minimal change disease, along with paraneoplastic syndrome and a special form of renal involvement in some viral infections, the likeliest causative scenario would be secreted factors, mainly cytokine(s). Since cytokines can modulate the inflammatory mechanisms, severity, and clinical outcomes of GN, it is rational to consider the umbrella term of cytokine GN as a new outlook to reclassify a group of previously known GN. We focus here, particularly, on cytokines that have the central "canonical effect" in the development of GN.

Remote liver ischemic preconditioning protects against renal ischemia/reperfusion injury via phosphorylation of extracellular signal-regulated kinases 1 and 2 in mice.

Perioperative acute kidney injury (AKI), which is mainly mediated by renal ischemia‒reperfusion (I/R) injury, is commonly observed in clinical practice. However, effective measures for preventing and treating this perioperative complication are still lacking in the clinic. Thus, we designed this study to examine whether remote liver ischemic preconditioning (RLIPC) has a protective effect on damage caused by renal I/R injury. In a rodent model, 30 mice were divided into five groups to assess the effects of RLIPC and ERK1/2 inhibition on AKI. The groups included the sham-operated (sham), kidney ischemia and reperfusion (CON), remote liver ischemic preconditioning (RLIPC), CON with the ERK1/2 inhibitor U0126 (CON+U0126), and RLIPC with U0126 (RLIPC+U0126). RLIPC consisted of 4 liver ischemia cycles before renal ischemia. Renal function and injury were assessed through biochemical assays, histology, cell apoptosis and protein phosphorylation analysis. RLIPC significantly mitigated renal dysfunction, tissue damage, inflammation, and apoptosis caused by I/R, which was associated with ERK1/2 phosphorylation. Furthermore, ERK1/2 inhibition with U0126 negated the protective effects of RLIPC and exacerbated renal injury. To summarize, we demonstrated that RLIPC has a strong renoprotective effect on kidneys post I/R injury and that this effect may be mediated by phosphorylation of ERK1/2.

Acute Kidney Injury in Children: A Focus for the General Pediatrician.

Acute kidney injury (AKI) presents significant challenges in pediatric care, often remaining underrecognized. This paper provides an overview of pediatric AKI, highlighting its epidemiology, pathophysiology, diagnosis, predisposing conditions, and treatment. AKI in children stems from diverse causes, including renal tubular damage, vasoconstriction, and inflammation. Diagnosis relies on traditional markers such as serum creatinine and urine output, alongside emerging biomarkers such as Cystatin C, NGAL, KIM-1, IL-18, TIMP-2 and IGFBP7, urinary calprotectin, URBP4, L-FABP, and clusterin. Various pediatric conditions predispose to AKI, including type 1 diabetes, pneumonia, bronchiolitis, appendicitis, gastroenteritis, COVID-19, multisystem inflammatory syndrome, sickle cell disease, and malignancies. Treatment entails supportive care with fluid management and, in severe cases, renal replacement therapy. Timely recognition and management are essential to mitigating adverse outcomes. Enhanced awareness and integration of novel biomarkers could improve pediatric AKI care, warranting further research for better diagnosis and management.