The Signaling Pathway of TNF Receptors: Linking Animal Models of Renal Disease to Human CKD

TMAO enhances TNF-α mediated fibrosis and release of inflammatory mediators from renal fibroblasts

Trimethylamine-N-oxide (TMAO) is a gut microbiota-derived metabolite and TNF-α is proinflammatory cytokine, both known to be associated with renal inflammation, fibrosis and chronic kidney disease. However, today there are no data showing the combined effect of TMAO and TNF-α on renal fibrosis-and inflammation. The aim of this study was to investigate whether TMAO can enhance the inflammatory and fibrotic effects of TNF-α on renal fibroblasts. We found that the combination of TNF-α and TMAO synergistically increased fibronectin release and total collagen production from renal fibroblasts. The combination of TMAO and TNF-α also promoted increased cell proliferation. Both renal proliferation and collagen production were mediated through Akt/mTOR/ERK signaling. We also found that TMAO enhanced TNF-α mediated renal inflammation by inducing the release of several cytokines (IL-6, LAP TGF-beta-1), chemokines (CXCL-6, MCP-3), inflammatory-and growth mediators (VEGFA, CD40, HGF) from renal fibroblasts. In conclusion, we showed that TMAO can enhance TNF-α mediated renal fibrosis and release of inflammatory mediators from renal fibroblasts in vitro. Our results can promote further research evaluating the combined effect of TMAO and inflammatory mediators on the development of kidney disease.

Periodontitis deteriorates renal fibrosis and macrophage infiltration in rats with chronic kidney disease

OBJECTIVE

The objective of this study was to examine the effect of periodontitis on renal function and morphology in rats with or without nephrectomy (Nx)-induced chronic kidney disease (CKD).

METHODS

Rats were divided into sham surgery (Sham), Sham with tooth ligation (ShamL), Nx, and NxL groups. Periodontitis was induced by tooth ligation at 16-week olds. Creatinine, alveolar bone area, and renal histopathology were analyzed at 20-week olds.

RESULTS

Creatinine did not differ between the Sham and ShamL groups or between the Nx and NxL groups. The ShamL and NxL groups (both p = 0.002) had less alveolar bone area than the Sham group. The NxL group had fewer glomeruli than the Nx group (p < 0.000). The periodontitis groups demonstrated more tubulointerstitial fibrosis (Sham vs. ShamL p = 0.002, Nx vs. NxL p < 0.000) and macrophage infiltration (Sham vs. ShamL p = 0.002, Nx vs. NxL p = 0.006) than the groups without periodontitis. Only the NxL group had greater renal TNFα expression than the Sham group (p < 0.003).

CONCLUSIONS

These suggest that periodontitis increases renal fibrosis and inflammation in the presence or absence of CKD but does not affect renal function. Periodontitis also increases TNFα expression in the presence of CKD.

Interleukin-10 enhances recruitment of immune cells in the neonatal mouse model of obstructive nephropathy

Urinary tract obstruction during renal development leads to inflammation, leukocyte infiltration, tubular cell death, and interstitial fibrosis. Interleukin-10 (IL-10) is an anti-inflammatory cytokine, produced mainly by monocytes/macrophages and regulatory T-cells. IL-10 inhibits innate and adaptive immune responses. IL-10 has a protective role in the adult model of obstructive uropathy. However, its role in neonatal obstructive uropathy is still unclear which led us to study the role of IL-10 in neonatal mice with unilateral ureteral obstruction (UUO). UUO serves as a model for congenital obstructive nephropathies, a leading cause of kidney failure in children. Newborn Il-10-/- and C57BL/6 wildtype-mice (WT) were subjected to complete UUO or sham-operation on the 2nd day of life. Neonatal kidneys were harvested at day 3, 7, and 14 of life and analyzed for different leukocyte subpopulations by FACS, for cytokines and chemokines by Luminex assay and ELISA, and for inflammation, programmed cell death, and fibrosis by immunohistochemistry and western blot. Compared to WT mice, Il-10-/- mice showed reduced infiltration of neutrophils, CD11bhi cells, conventional type 1 dendritic cells, and T-cells following UUO. Il-10-/- mice with UUO also showed a reduction in pro-inflammatory cytokine and chemokine release compared to WT with UUO, mainly of IP-10, IL-1α, MIP-2α and IL-17A. In addition, Il-10-/- mice showed less necroptosis after UUO while the rate of apoptosis was not different. Finally, α-SMA and collagen abundance as readout for fibrosis were similar in Il-10-/- and WT with UUO. Surprisingly and in contrast to adult Il-10-/- mice undergoing UUO, neonatal Il-10-/- mice with UUO showed a reduced inflammatory response compared to respective WT control mice with UUO. Notably, long term changes such as renal fibrosis were not different between neonatal Il-10-/- and neonatal WT mice with UUO suggesting that IL-10 signaling is different in neonates and adults with UUO.

Full-length transcriptomics study of Ustiloxins-induced hepatocyte injury

Ustiloxins is a mycotoxin produced by the metabolism of Rice false smut. Studies have shown that Ustiloxins may be toxic to animals, but there is still a lack of toxicological evidence. The liver, as the main organ for the biotransformation of foreign chemicals, may be the direct target organ of Ustiloxins toxicity. In this study, we found that cell viability decreased in a dose- and time-dependent manner when BNL CL.2 cells were treated with different concentrations of Ustiloxins (0, 5, 10, 20, 30, 40, 60, 80, 100, 150 and 200 μg/mL) for 24 and 48 h. In addition, scanning electron microscope observation showed that the cell membrane of the experimental group was damaged, with the appearance of apoptotic bodies. Moreover, the ROS and GSH levels were significantly increased in cells exposed to Ustiloxins. We analyzed the key action targets of Ustiloxins on hepatocyte injury using full-length transcriptomics. A total of 1099 differentially expressed genes were screened, of which 473 genes were up-regulated, and 626 genes were down-regulated. Besides, we also found that the expression of MCM7 and CDC45 in BNL CL.2 cells treated with Ustiloxins decreased, and the expression of CCl-2, CYP1b1, CYP4f13, and GSTM1 increased according to qRT-PCR. Ustiloxins might change CYP450 and GST-related genes, affect DNA replication and cell cycle, and lead to oxidative stress and liver cell injury.

Interleukin-6, tumor necrosis factor-α, and high-sensitivity C-reactive protein for optimal immunometabolic profiling of the lifestyle-related cardiorenal risk

OBJECTIVES

The present study aimed to identify optimal inflammatory biomarkers involved in cardiorenal risk in response to major lifestyle factors.

METHODS

One hundred and twenty-nine adults aged 35-77 years participated voluntarily from 2017 to 2019 (Córdoba, Argentina) in a cross-sectional study to collect sociodemographic, clinical, and lifestyle data. Blood biomarkers (different cytokines, monocyte chemoattractant protein-1 [MCP-1], and high-sensitivity C-reactive protein [hs-CRP]) were measured using standard methods and then evaluated by principal component analysis and structural equation modeling (SEM) according to Mediterranean diet adherence, physical activity level, and waist circumference, while cardiorenal risk involved blood diastolic pressure, HDL-cholesterol, triacylglycerols, creatinine, and glycosylated hemoglobin.

RESULTS

A principal component included TNF-α (tumor necrosis factor-alpha), IL-8 (interleukin-8), IL-6 (interleukin-6), hs-CRP, and MCP-1, with absolute rotated factor loadings >0.10. SEM showed that IL-6 (β=0.38, 95 % IC=0.08-0.68), hs-CRP (β=0.33, 95 % IC=0.17-0.48), and TNF-α (β=0.22, 95 % IC=0.11-0.32) were the mediators that better explained an inflammatory profile positively related to waist circumference (β=0.77, 95 % IC=0.61-0.94). Moreover, this profile was associated with an increased cardiorenal risk (β=0.78, 95 % IC=0.61-0.94), which was well-defined by the variable used.

CONCLUSIONS

Immune mediators are key elements in profiling the cardiorenal risk associated with lifestyle factors, for which the combination of hs-CRP, IL-6, and TNF-α has emerged as a robust indicator. This work reaffirms the need for biomarker optimization for early diagnosis and risk assessment.

Natural Polyphenols in Cancer Management: Promising Role, Mechanisms, and Chemistry

BACKGROUND

Although cancers emerge rapidly and cancer cells divide aggressively, which affects our vital organ systems. Recently, cancer treatments are targeted immune systems mediating intrinsic cellular mechanisms. Natural efficacious polyphenols have been exhibited to help prevent most cancers and reverse the progression of cancers.

METHODS

Many resources have been used to know the promising role of polyphenols in preventing and treating cancers. The electronic databases include Science Direct, Google, Google Scholar, PubMed, and Scopus. The search was limited to the English language only.

RESULTS

Polyphenols have been reported as anti-metastatic agents that explore the promising role of these compounds in cancer prevention. Such agents act through many signaling pathways, including PI3K/Akt and TNF-induced signaling pathways. The chemical modifications of polyphenols and the structure-activity relationships (SARs) between polyphenols and anticancer activities have also been discussed.

CONCLUSION

Many research papers were reported to explain the anti-cancer potential of Polyphenols, The SARs between polyphenols and anti-cancer activities, which correlate structures of polyphenols with significant chemotherapeutic action. The mechanism of anti-cancer potential is to be added for searching for new anti-cancer natural products.

Currently Used Methods to Evaluate the Efficacy of Therapeutic Drugs and Kidney Safety

Kidney diseases with kidney failure or damage, such as chronic kidney disease (CKD) and acute kidney injury (AKI), are common clinical problems worldwide and have rapidly increased in prevalence, affecting millions of people in recent decades. A series of novel diagnostic or predictive biomarkers have been discovered over the past decade, enhancing the investigation of renal dysfunction in preclinical studies and clinical risk assessment for humans. Since multiple causes lead to renal failure, animal studies have been extensively used to identify specific disease biomarkers for understanding the potential targets and nephropathy events in therapeutic insights into disease progression. Mice are the most commonly used model to investigate the mechanism of human nephropathy, and the current alternative methods, including in vitro and in silico models, can offer quicker, cheaper, and more effective methods to avoid or reduce the unethical procedures of animal usage. This review provides modern approaches, including animal and nonanimal assays, that can be applied to study chronic nonclinical safety. These specific situations could be utilized in nonclinical or clinical drug development to provide information on kidney disease.

Expression of TNFR1, VEGFA, CD147 and MCT1 as early biomarkers of diabetes complications and the impact of aging on this profile

Hyperglycemia leads to microvascular lesions in various tissues. In diabetic nephropathy-DN, alterations in usual markers reflect an already installed disease. The study of new biomarkers for the early detection of diabetic complications can bring new prevention perspectives. Rats were divided into diabetic adult-DMA-or elderly-DME and control sham adult-CSA-or control sham elderly-CSE. Blood and urine samples were collected for biochemical analysis. Bulbar region, cardiac, hepatic and renal tissues were collected for target gene expression studies. As result, DMA showed decreased TNFR1, MCT1 and CD147 expression in the bulbar region, TNFR1 in the heart, VEGFA and CD147 in the kidney and TNFR1 in blood. Positive correlations were found between TNFR1 and MCT1 in the bulbar region and HbA1c and plasma creatinine, respectively. DME showed positive correlation in the bulbar region between TNFR1 and glycemia, in addition to negative correlations between CD147 in the heart versus glycemia and urea. We concluded that the initial hyperglycemic stimulus already promotes changes in the expression of genes involved in the inflammatory and metabolic pathways, and aging alters this profile. These changes prior to the onset of diseases such as DN, show that they have potential for early biomarkers studies.

Chronic Kidney Disease: Underlying Molecular Mechanisms-A Special Issue Overview

Chronic kidney disease (CKD) is an epidemic health issue that requires global attention [...].

Kidney Damage in Long COVID: Studies in Experimental Mice

Signs and symptoms involving multiple organ systems which persist for weeks or months to years after the initial SARS-CoV-2 infection (also known as PASC or long COVID) are common complications of individuals with COVID-19. We recently reported pathophysiological changes in various organs post-acute infection of mice with mouse hepatitis virus-1 (MHV-1, a coronavirus) (7 days) and after long-term post-infection (12 months). One of the organs severely affected in this animal model is the kidney, which correlated well with human studies showing kidney injury post-SARS-CoV-2 infection. Our long-term post-infection pathological observation in kidneys includes the development of edema and inflammation of the renal parenchyma, severe acute tubular necrosis, and infiltration of macrophages and lymphocytes, in addition to changes observed in both acute and long-term post-infection, which include tubular epithelial cell degenerative changes, peritubular vessel congestion, proximal and distal tubular necrosis, hemorrhage in the interstitial tissue, and vacuolation of renal tubules. These findings strongly suggest the possible development of renal fibrosis, in particular in the long-term post-infection. Accordingly, we investigated whether the signaling system that is known to initiate the above-mentioned changes in kidneys in other conditions is also activated in long-term post-MHV-1 infection. We found increased TGF-β1, FGF23, NGAL, IL-18, HIF1-α, TLR2, YKL-40, and B2M mRNA levels in long-term post-MHV-1 infection, but not EGFR, TNFR1, BCL3, and WFDC2. However, only neutrophil gelatinase-associated lipocalin (NGAL) increased in acute infection (7 days). Immunoblot studies showed an elevation in protein levels of HIF1-α, TLR-2, and EGFR in long-term post-MHV-1 infection, while KIM-1 and MMP-7 protein levels are increased in acute infection. Treatment with a synthetic peptide, SPIKENET (SPK), which inhibits spike protein binding, reduced NGAL mRNA in acute infection, and decreased TGF-β1, BCL3 mRNA, EGFR, HIF1-α, and TLR-2 protein levels long-term post-MHV-1 infection. These findings suggest that fibrotic events may initiate early in SARS-CoV-2 infection, leading to pronounced kidney fibrosis in long COVID. Targeting these factors therapeutically may prevent acute or long-COVID-associated kidney complications.

Deciphering the pharmacological mechanisms of Rostellularia procumbens (L) Nees. Extract alleviates adriamycin-induced nephropathy in vivo and in vitro

BACKGROUND

Rostellularia procumbens (L) Nees. is an effective traditional Chinese herbal medicine for the treatment of patients with chronic glomerulonephritis (CGN) in the clinic. However, the underlying molecular mechanisms need further elucidation.

PURPOSE

This study aims to investigate the renoprotective mechanisms of n-butanol extract from Rostellularia procumbens (L) Nees. (J-NE) in vivo and in vitro.

METHODS

The components of J-NE were analyzed by UPLC-MS/MS. In vivo, the nephropathy model was induced in mice by tail vein injection with adriamycin (10 mg·kg^-1), and mice were treated with vehicle or J-NE or benazepril by daily gavage. In vitro, MPC5 cells exposed to adriamycin (0.3 μg/ml) were treated with J-NE. The effects of J-NE inhibit podocyte apoptosis and protect against adriamycin-induced nephropathy were determined by Network pharmacology, RNA-seq, qPCR, ELISA, immunoblotting, flow cytometry, and TUNEL assay, according to the experimental protocols.

RESULT

The results showed that treatment significantly improved ADR-induced renal pathological changes, and the therapeutic mechanism of J-NE was related to the inhibition of podocyte apoptosis. Further molecular mechanism studies found that J-NE inhibited inflammation, increase the proteins expression levels of Nephrin and Podocin, reduce TRPC6 and Desmin expression levels and calcium ion levels in podocytes, and decrease the proteins expression levels of PI3K, p-PI3K, Akt and p-Akt to attenuated apoptosis. Furthermore, 38 compounds of J-NE were identified.

CONCLUSION

J-NE exerted the renoprotective effects by inhibiting podocyte apoptosis, which provides effective evidence for the treatment of J-NE targeting renal injury in CGN.

Zeb1 facilitates corneal epithelial wound healing by maintaining corneal epithelial cell viability and mobility

The cornea is the outmost ocular tissue and plays an important role in protecting the eye from environmental insults. Corneal epithelial wounding provokes pain and fear and contributes to the most ocular trauma emergency assessments worldwide. ZEB1 is an essential transcription factor in development; but its roles in adult tissues are not clear. We identify Zeb1 is an intrinsic factor that facilitates corneal epithelial wound healing. In this study, we demonstrate that monoallelic deletion of Zeb1 significantly expedites corneal cell death and inhibits corneal epithelial EMT-related cell migration upon an epithelial debridement. We provide evidence that Zeb1-regulation of corneal epithelial wound healing is through the repression of genes required for Tnfa-induced epithelial cell death and the induction of genes beneficial for epithelial cell migration. We suggest utilizing TNF-α antagonists would reduce TNF/TNFR1-induced cell death in the corneal epithelium and inflammation in the corneal stroma to help corneal wound healing.

Lyn attenuates sepsis-associated acute kidney injury by inhibition of phospho-STAT3 and apoptosis

Sepsis-associated acute kidney injury (SA-AKI) is a life-threatening condition associated with high mortality and morbidity. However, the underlying pathogenesis of SA-AKI is still unclear. Lyn belongs to Src family kinases (SFKs), which exert numerous biological functions including modulation in receptor-mediated intracellular signaling and intercellular communication. Previous studies demonstrated that Lyn gene deletion obviously aggravates LPS-induced lung inflammation, but the role and possible mechanism of Lyn in SA-AKI have not been reported yet. Here, we found that Lyn protected against renal tubular injury in cecal ligation and puncture (CLP) induced AKI mouse model by inhibition of signal transducer and activator of transcription 3 (STAT3) phosphorylation and cell apoptosis. Moreover, Lyn agonist MLR-1023 pretreatment improved renal function, inhibited STAT3 phosphorylation and decreased cell apoptosis. Thus, Lyn appears to play a crucial role in orchestrating STAT3-mediated inflammation and cell apoptosis in SA-AKI. Hence, Lyn kinase may be a promising therapeutic target for SA-AKI.

TNFR2 as a Potential Biomarker for Early Detection and Progression of CKD

The inflammatory pathway driven by TNF-α, through its receptors TNFR1 and TNFR2, is a common feature in the pathogenesis of chronic kidney disease (CKD), regardless of the initial disease cause. Evidence correlates the chronic inflammatory status with decreased renal function. Our aim was to evaluate the potential of TNF receptors as biomarkers for CKD diagnosis and staging, as well as their association with the progression of renal lesions, in rat models of early and moderate CKD. We analyzed the circulating levels of inflammatory molecules—tumor necrosis factor-alpha (TNF-α), tumor necrosis factor receptor 1 (TNFR1) and 2 (TNFR2) and tissue inhibitor of metalloproteinase-1 (TIMP-1)—and studied their associations with TNFR1 and TNFR2 renal expression, glomerular and tubulointerstitial lesions, and with biomarkers of renal (dys)function. An increase in all inflammatory markers was observed in moderate CKD, as compared to controls, but only circulating levels of both TNFR1 and TNFR2 were significantly increased in the early disease; TNFR2 serum levels were negatively correlated with eGFR. However, only TNFR2 renal expression increased with CKD severity and showed correlations with the score of mild and advanced tubular lesions. Our findings suggest that renal TNFR2 plays a role in CKD development, and has potential to be used as a biomarker for the early detection and progression of the disease. Still, the potential value of this biomarker in disease progression warrants further investigation.

TNF and IL6/Jak2 signaling pathways are the main contributors of the glia-derived neuroinflammation present in Lafora disease, a fatal form of progressive myoclonus epilepsy

Lafora disease (LD; OMIM#254780) is a rare form of progressive myoclonus epilepsy (prevalence <1:1,000,000) characterized by the accumulation of insoluble deposits of aberrant glycogen (polyglucosans), named Lafora bodies, in the brain but also in peripheral tissues. LD is the most severe form of the group of progressive myoclonus epilepsies, since patients present a rapid deterioration and dementia with amplification of seizures, leading to death after a decade from the onset of the first symptoms. We have recently described that reactive glia-derived neuroinflammation should be considered a novel hallmark of LD since we observed a florid upregulation of differentially expressed genes in both LD mouse lines, which were mainly related to mediators of inflammatory response. In this work, we define an upregulation of the expression of mediators of the TNF and IL6/JAK2 signaling pathways in LD. In addition, we describe the activation of the non-canonical form of the inflammasome. Furthermore, we describe the infiltration of peripheral immune cells in the brain parenchyma, which could aggravate glia-derived neuroinflammation. Finally, we describe CXCL10 and S100b as blood biomarkers of the disease, which will allow the study of the progression of the disease using serum blood samples. We consider that the identification of these initial inflammatory changes in LD will be very important to implement possible anti-inflammatory therapeutic strategies to prevent the development of the disease.