Exclusive expression of transmembrane TNF aggravates acute glomerulonephritis despite reduced leukocyte infiltration and inflammation

Glycolytic Activation of CD14+ Intestinal Macrophages Contributes to the Inflammatory Responses via Exosomal Membrane Tumor Necrosis Factor in Crohn's Disease

BACKGROUND

Macrophage (Mφ) activation plays a critical role in the inflammatory response. Activated Mφ go through profound reprogramming of cellular metabolism. However, changes in their intracellular energy metabolism and its effect on inflammatory responses in Crohn's disease (CD) remain currently unclear. The aim of this study is to explore metabolic signatures of CD14+ Mφ and their potential role in CD pathogenesis as well as the underlying mechanisms.

METHODS

CD14+ Mφ were isolated from peripheral blood or intestinal tissues of CD patients and control subjects. Real-time flux measurements and enzyme-linked immunosorbent assay were used to determine the inflammatory states of Mφ and metabolic signatures. Multiple metabolic routes were suppressed to determine their relevance to cytokine production.

RESULTS

Intestinal CD14+ Mφ in CD patients exhibited activated glycolysis compared with those in control patients. Specifically, macrophagic glycolysis in CD largely induced inflammatory cytokine release. The intestinal inflammatory microenvironment in CD elicited abnormal glycolysis in Mφ. Mechanistically, CD14+ Mφ derived exosomes expressed membrane tumor necrosis factor (TNF), which engaged TNFR2 and triggered glycolytic activation via TNF/nuclear factor κB autocrine and paracrine signaling. Importantly, clinically applicable anti-TNF antibodies effectively prevented exosomal membrane TNF-induced glycolytic activation in CD14+ Mφ.

CONCLUSIONS

CD14+ Mφ take part in CD pathogenesis by inducing glycolytic activation via membrane TNF-mediated exosomal autocrine and paracrine signaling. These results provide novel insights into pathogenesis of CD and enhance understanding of the mechanisms of anti-TNF agents.

Exploring the potential mechanisms of Shiwei Hezi pill against nephritis based on the method of network pharmacology

Objective: We aimed to reveal the potential active ingredients, targets and pathways of Shiwei Hezi pill (SHP) in the treatment of nephritis based on systematic network pharmacology. Methods: The online database was used to screen the common targets of SHP and nephritis, and the interaction between targets was analyzed. Gene Ontology (GO) functional annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis were performed using the Bioinformatics website. Molecular docking was carried out to verify the correlation between core ingredients and key targets. Cytoscape 3.6.1 was applied to perform protein-protein interactions (PPT) network construction and data visualization. Results: A total of 82 active ingredients in SHP were screened, and 140 common targets of SHP and nephritis were obtained. Our results demonstrated that TNF, AKT1 and PTGS2 might be the key targets of SHP in the treatment of nephritis. GO enrichment analysis yielded 2163 GO entries (p < 0.05), including 2,014 entries of the biological process (BP) category, 61 entries of the cell composition (CC) category and 143 entries of the molecular function (MF) category. KEGG pathway enrichment analysis produced 186 signaling pathways (p < 0.05), involving the AGE-RAGE, IL-17and TNF signaling pathways. The results of molecular docking showed that three active ingredients in SHP (quercetin, kaempferol and luteolin) could effectively bind to the TNF, AKT1 and PTGS2 targets. Conclusion: The effective active ingredients in SHP may regulate multiple signaling pathways through multiple targets, thereby exhibiting a therapeutic effect on nephritis.

Apoptotic cell death in disease-Current understanding of the NCCD 2023

Apoptosis is a form of regulated cell death (RCD) that involves proteases of the caspase family. Pharmacological and genetic strategies that experimentally inhibit or delay apoptosis in mammalian systems have elucidated the key contribution of this process not only to (post-)embryonic development and adult tissue homeostasis, but also to the etiology of multiple human disorders. Consistent with this notion, while defects in the molecular machinery for apoptotic cell death impair organismal development and promote oncogenesis, the unwarranted activation of apoptosis promotes cell loss and tissue damage in the context of various neurological, cardiovascular, renal, hepatic, infectious, neoplastic and inflammatory conditions. Here, the Nomenclature Committee on Cell Death (NCCD) gathered to critically summarize an abundant pre-clinical literature mechanistically linking the core apoptotic apparatus to organismal homeostasis in the context of disease.

Dynamic changes in marker components during the stir-frying of Pharbitidis Semen, and network analysis of its potential effects on nephritis

Introduction: Pharbitidis Semen (PS) has been widely used in traditional Chinese medicine to treat several diseases such as nephritis. PS is usually stir-fried to enhance its therapeutic efficacy before use in clinical practice. However, the changes in phenolic acids during stir-frying and the mechanisms of their therapeutic effects on nephritis are still unclear.

Methods: Here, we studied the processing-induced chemical changes and elucidated the mechanism of PS in the treatment of nephritis. We determined the levels of the 7 phenolic acids in raw PS (RPS) and stir-fried PS (SPS) using high-performance liquid chromatography, analyzed the dynamic compositional changes during stir-frying, and used network analysis and molecular docking to predict and verify compound targets and pathways corresponding to nephritis.

Results: The dynamic changes in the 7 phenolic acids in PS during stir-frying are suggestive of a transesterification reaction. Pathway analysis revealed that the targets of nephritis were mainly enriched in the AGE-RAGE, hypoxia-inducible factor-1, interleukin-17, and tumor necrosis factor signaling pathways among others. Molecular docking results showed that the 7 phenolic acids had good binding ability with the key nephritic targets.

Discussion: The potential pharmaceutical basis, targets, and mechanisms of PS in treating nephritis were explored. Our findings provide a scientific basis for the clinical use of PS in treating nephritis.

Responses to Ang II (Angiotensin II), Salt Intake, and Lipopolysaccharide Reveal the Diverse Actions of TNF-α (Tumor Necrosis Factor-α) on Blood Pressure and Renal Function

TNF-α (tumor necrosis factor-alpha) is the best known as a proinflammatory cytokine; yet, this cytokine also has important immunomodulatory and regulatory functions. As the effects of TNF-α on immune system function were being revealed, the spectrum of its activities appeared in conflict with each other before investigators defined the settings and mechanisms by which TNF-α contributed to both host defense and chronic inflammation. These effects reflect self-protective mechanisms that may become harmful when dysregulated. The paradigm of physiological and pathophysiological effects of TNF-α has since been uncovered in the lung, colon, and kidney where its role has been identified in pulmonary edema, electrolyte reabsorption, and blood pressure regulation, respectively. Recent studies on the prohypertensive and inflammatory effects of TNF-α in the cardiovascular system juxtaposed to those related to NaCl and blood pressure homeostasis, the response of the kidney to lipopolysaccharide, and protection against bacterial infections are helping define the mechanisms by which TNF-α modulates distinct functions within the kidney. This review discusses how production of TNF-α by renal epithelial cells may contribute to regulatory mechanisms that not only govern electrolyte excretion and blood pressure homeostasis but also maintain the appropriate local hypersalinity environment needed for optimizing the innate immune response to bacterial infections in the kidney. It is possible that the wide range of effects mediated by TNF-α may be related to severity of disease, amount of inflammation and TNF-α levels, and the specific cell types that produce this cytokine, areas that remain to be investigated further.

Identification of Taohong Siwu Decoction in Treating Chronic Glomerulonephritis Using Network Pharmacology and Molecular Docking

Background: Based on network pharmacology and molecular docking technology, the pharmacological mechanism of Taohong Siwu Decoction (THSWD) in the treatment of chronic glomerulonephritis (CGN) was analyzed to provide a theoretical basis for the subsequent development of new drugs and the clinical application of Traditional Chinese Medicine (TCM). Methods: Active ingredients of drugs and disease target genes were obtained from Traditional Chinese Medicine Database and Analysis Platform (TCMSP) database and GeneCards database. The “drug component target” network of THSWD was constructed using Cytoscape version 3.8.2 software. The protein interaction was analyzed using STRING platform, the protein–protein interaction (PPI) network was constructed, and the potential protein function modules in the network were mined. Metascape platform was used to analyze “drug component target” and its biological processes and pathways. The clusterProfiler R package was called to perform kyoto encyclopedia of genes and genomes (KEGG) pathway and gene ontology (GO) function enrichment analysis on CGN-related targets regulated by THSWD. Molecular docking verification was performed by AutoDock Vina software. Results: THSWD has 205 target genes and 45 active components, 104 of which are cross with the CGN inflammatory gene. Its main active ingredients, stigmasterol, kaempferol, and sitosterol, have positive relationships with the inflammatory targets of CGN, tumor necrosis factor (TNF), IL-6, AKT1, and MAPK14. THSWD modulates the biological pathway of CGN and mainly acts on TNF-α signal pathway, interleukin-17 signal pathway, etc., whose main functions are response to lipid sugar, heme binding, G protein-coupled amine receptor activity, etc. The results of molecular docking showed that the main active compounds could bind to the core targets and showed good affinity. Conclusion: The molecular mechanism of THSWD in the treatment of CGN from the perspective of network pharmacology are components such as beta-sitosterol, kaempferol, and quercetin and key action targets such as TNF, IL-6, AKT1 protein kinase, and MAPK14 protein kinase play a synergistic role in autoimmune, infection, and inflammatory response-related pathways.

Metformin improves renal injury of MRL/lpr lupus-prone mice via the AMPK/STAT3 pathway

Objective

Lupus nephritis (LN) is a major complication and cause of death among patients with SLE. This research used in vivo and in vitro experiments to explore the therapeutic potential of metformin in kidney injury from LN-induced inflammation.

Methods

In vivo study, 8-week-old MRL/MpJ-Faslpr/J (MRL/lpr) mice were randomly divided into two groups (n=12 each): daily administration of 0.3 mg/mL metformin in drinking water and control (water only). Body weight and urinary samples were measured biweekly. Mice were sacrificed after 8-week treatment to harvest serum, lymph nodes, spleen and kidneys. In vitro study, human kidney-2 (HK-2) cells were pretreated with 1 mM metformin for 1 hour and then stimulated with 20 µg/mL lipopolysaccharides (LPS) or 10 ng/mL tumour necrosis factor-α (TNF-α) for another 48 hours. Protein was collected for subsequent analysis.

Results

We found that metformin administration improved renal function in MRL/lpr lupus-prone mice, measured by decreased urea nitrogen and urinary proteins. Metformin reduced immunoglobulin G and complement C3 deposition in glomeruli. The treatment also downregulated systemic and renal inflammation, as seen in decreased renal infiltration of F4/80-positive macrophages and reduced splenic and renal MCP-1 (monocyte chemoattractant protein-1) and TNF-α, and renal IL-1β (interleukin 1β) expression. Metformin administration decreased renal expression of necroptosis markers p-RIPK1 (phosphorylated receptor-interacting protein kinase 1) and p-MLKL, along with tubular injury marker KIM-1 (kidney injury molecule-1) in lupus mice. In addition, metformin alleviated the necroptosis of HK-2 cells stimulated by LPS and TNF-α, evidencing by a decrease in the expression of necroptosis markers p-RIPK1, p-RIPK3 and p-MLKL, and the inflammasome-related markers NLRP3 (NLR family pyrin domain containing 3), ASC (apoptosis-associated speck-like protein containing a CARD), caspase-1. Mechanistically, metformin treatment upregulated p-AMPK (phosphorylated AMP-activated protein kinase) and downregulated p-STAT3 (phosphorylated signal transducer and activator of transcription 3) expression in the kidneys. Moreover, AMPKα2 knockdown abolished the protective effects of metformin in vitro.

Conclusions

Metformin alleviated kidney injury in LN though suppressing renal necroptosis and inflammation via the AMPK/STAT3 pathway.

Exploring the mechanism of Jianpi Qushi Huayu Formula in the treatment of chronic glomerulonephritis based on network pharmacology

This study was to explore the effective components, potential targets, and pathways of Jianpi Qushi Huayu Formula (JQHF) for the treatment of chronic glomerulonephritics (CGN). First, the Chinese Medicine System Pharmacology Database and Analysis Platform (TCMSP), GeneCards, and OMIM databases were used to collect the major active components of JQHF and potential therapeutic targets of CGN. Then, functional enrichment analysis was performed to clarify the mechanisms of the JQHF on CGN. Subsequently, molecular docking was simulated to assess the binding ability of key targets and major active components. Finally, quantitative real-time PCR and western blot were performed for experimental verification of cells in vitro. A total of 55 active ingredients contained and 220 putative identified targets were screened from JQHF, of which 112 overlapped with the targets of CGN and were considered potential therapeutic targets. Then, we found quercetin and kaempferol are two key ingredients of JQHF, which may act on the top 10 screened targets of PPI, affecting CGN through related signal transduction pathways. Subsequently, molecular docking predicted that quercetin and kaempferol bind firm with the top 10 core targets of PPI. Further experiment verified some results and showed that JQHF has protected glomerular mesangial cells from lipopolysaccharide-induced inflammation by inhibiting expressions of IL6, TNF-α, and AKT1, and activating expressions of VEGFA. Based on network pharmacology, we explored the multi-component, multi-target, and multi-pathway characteristics of JQHF in treating CGN, and found that JQHF could act on IL6, TNF-α, VEGFA, and AKT1 to exert the effect of anti-CGN, which provided new ideas and methods for further research on the mechanism of JQHF in treating CGN.

Polygala fallax Hemsl combined with compound Sanqi granules relieves glomerulonephritis by regulating proliferation and apoptosis of glomerular mesangial cells

Objectives

Glomerulonephritis is a serious kidney disease that can induce end-stage renal failure. The aberrant proliferation of mesangial cells is a cause of glomerulonephritis. Traditional Chinese medicines, such as Astragalus and Salvia miltrorrhiza, play important roles in the treatment of kidney-related diseases. However, the effects of a combination of Astragalus and S. miltrorrhiza-containing traditional Chinese medicines (Polygala fallax Hemsl and compound Sanqi granules) on glomerulonephritis are unclear.

Methods

HRM cells (human mesangial cells) were stimulated with lipopolysaccharide to simulate glomerulonephritis. Separately, compound Sanqi granules and P. fallax Hemsl were administered to nude mice in various combinations. Serum was collected from the treated mice and added to HRM cells; the proliferation and apoptosis characteristics of the cells were assessed.

Results

The proliferation of HRM cells was inhibited after exposure to serum from treated mice. Exposure to serum from treated mice moderately induced apoptosis of HRM cells and lowered the expression levels of TNF-α, IL-1β, and IL-6.

Conclusions

Combination treatment with compound Sanqi granules and P. fallax Hemsl exerts a therapeutic effect on glomerulonephritis by inhibiting the proliferation of mesangial cells, while inducing apoptosis in those cells.

KLF4 in Macrophages Attenuates TNFα-Mediated Kidney Injury and Fibrosis

BACKGROUND

Polarized macrophage populations can orchestrate both inflammation of the kidney and tissue repair during CKD. Proinflammatory M1 macrophages initiate kidney injury, but mechanisms through which persistent M1-dependent kidney damage culminates in fibrosis require elucidation. Krüppel-like factor 4 (KLF4), a zinc-finger transcription factor that suppresses inflammatory signals, is an essential regulator of macrophage polarization in adipose tissues, but the effect of myeloid KLF4 on CKD progression is unknown.

METHODS

We used conditional mutant mice lacking KLF4 or TNFα (KLF4's downstream effector) selectively in myeloid cells to investigate macrophage KLF4's role in modulating CKD progression in two models of CKD that feature robust macrophage accumulation, nephrotoxic serum nephritis, and unilateral ureteral obstruction.

RESULTS

In these murine CKD models, KLF4 deficiency in macrophages infiltrating the kidney augmented their M1 polarization and exacerbated glomerular matrix deposition and tubular epithelial damage. During the induced injury in these models, macrophage-specific KLF4 deletion also exacerbated kidney fibrosis, with increased levels of collagen 1 and α-smooth muscle actin in the injured kidney. CD11b⁺Ly6C^hi myeloid cells isolated from injured kidneys expressed higher levels of TNFα mRNA versus wild-type controls. In turn, mice bearing macrophage-specific deletion of TNFα exhibited decreased glomerular and tubular damage and attenuated kidney fibrosis in the models. Moreover, treatment with the TNF receptor-1 inhibitor R-7050 during nephrotoxic serum nephritis reduced damage, fibrosis, and necroptosis in wild-type mice and mice with KLF4-deficient macrophages, and abrogated the differences between the two groups in these parameters.

CONCLUSIONS

These data indicate that macrophage KLF4 ameliorates CKD by mitigating TNF-dependent injury and fibrosis.