Programmed Cell Death in Sepsis Associated Acute Kidney Injury

Apigenin-Mediated ESCRT-III Activation and Mitophagy Alleviate LPS-Induced Necroptosis in Renal Cells

Apigenin (API) is a flavonoid widely distributed in vegetables and fruits that exhibits numerous biological functions. Lipopolysaccharide (LPS), a key component of the outer membrane of Gram-negative bacteria, can cause kidney injury when released into the bloodstream. Necroptosis is a form of programmed cell death characterized by the rupture of cell membranes. Excessive occurrence of necroptosis can lead to substantial damage to cells and tissues. In the study, we discovered that API could mitigate LPS-induced kidney injury in mice and alleviate LPS-induced necroptosis in Normal Rat Kidney-52E (NRK-52E) cells by targeting the mitochondrial reactive oxygen species (mtROS)-RIPK3-MLKL pathway. Further mechanistic studies revealed that API could potentially activate the endosomal sorting complexes required for transport-III (ESCRT-III), and activated ESCRT-III could repair cell membrane rupture caused by LPS-induced necroptosis. Simultaneously, we discovered that activated ESCRT-III could promote mitophagy, which facilitates the timely removal of damaged mitochondria and reduces intracellular mtROS levels. In conclusion, our results suggested that API alleviates LPS-induced renal cell necroptosis by activating ESCRT-III-dependent membrane repair and mitophagy. Our study provides new insights into the daily dietary intake of API to alleviate kidney injury caused by LPS.

Pyroptosis in sepsis-associated acute kidney injury: mechanisms and therapeutic perspectives

Sepsis-associated acute kidney injury (S-AKI) is a severe complication characterized by high morbidity and mortality, driven by multi-organ dysfunction. Recent evidence suggests that pyroptosis, a form of programmed cell death distinct from apoptosis and necrosis, plays a critical role in the pathophysiology of S-AKI. This review examines the mechanisms of pyroptosis, focusing on inflammasome activation (e.g., NLRP3), caspase-mediated processes, and the role of Gasdermin D in renal tubular damage. We also discuss the contributions of inflammatory mediators, oxidative stress, and potential therapeutic strategies targeting pyroptosis, including inflammasome inhibitors, caspase inhibitors, and anti-inflammatory therapies. Lastly, we highlight the clinical implications and challenges in translating these findings into effective treatments, underscoring the need for personalized medicine approaches in managing S-AKI.

Screening and analysis of programmed cell death related genes and targeted drugs in sepsis

OBJECTIVE

This study employed bioinformatics techniques to identify diagnostic genes associated with programmed cell death (PCD) and to explore potential therapeutic agents for the treatment of sepsis.

METHODS

Gene expression profiles from sepsis patients were analyzed to identify differentially expressed genes (DEGs) and hub genes through Weighted Gene Co-expression Network Analysis (WGCNA). Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were conducted to elucidate the functions of the DEGs. PCD-related genes were cross-referenced with the identified DEGs. Diagnostic genes were selected using Least Absolute Shrinkage and Selection Operator (LASSO) and Random Forest (RF) methodologies. Single-cell RNA sequencing was utilized to assess gene expression in blood cells, while CIBERSORT was employed to evaluate immune cell infiltration. A transcription factor (TF)-microRNA (miRNA)-hub gene network was constructed, and potential therapeutic compounds were predicted using the Drug Gene Interaction Database (DGIdb). Mendelian Randomization (MR) methods were applied to analyze genome-wide association study (GWAS) data for S100A9, TXN, and GSTO1.

RESULTS

The analysis revealed 2156 PCD-related genes, 714 DEGs, and 1198 hub genes, with 88 genes enriched in immune and cell death pathways. Five pivotal PCD-related genes (IRAK3, S100A9, TXN, NFATC2, and GSTO1) were identified, leading to the construction of a network comprising six transcription factors and 171 microRNAs. Additionally, seven drugs targeting S100A9, TXN, and NFATC2 were identified. MR analysis suggested that a decrease in GSTO1 levels is associated with an increased risk of sepsis, and that sepsis influences the levels of S100A9, TXN, and GSTO1.

CONCLUSIONS

Through bioinformatics approaches, this study successfully identified five genes (IRAK3, S100A9, TXN, NFATC2, and GSTO1) associated with programmed cell death in the context of sepsis. This research identified seven candidate drugs for sepsis treatment and established a methodological framework for predicting biomarkers and drug targets that could be applicable to other diseases.

Pharmacologic and endotoxic reprogramming of renal vasodilatory, inflammatory, and apoptotic blemishes in weaning preeclamptic rats

Preeclampsia (PE) and peripartum sepsis are two complications of pregnancy and are often associated with disturbed renal function due possibly to dysregulated renin angiotensin system. Here we evaluated hemodynamic and renal consequences of separate and combined PE and sepsis insults in weaning mothers and tested whether this interaction is influenced by prenatally-administered losartan (AT1-receptor blocker) or pioglitazone (PPARγ agonist). The PE-rises in blood pressure and proteinuria induced by gestational nitric oxide synthase inhibition (L-NAME, 50 mg/kg/day for 7 days) were attenuated after simultaneous treatment with losartan or pioglitazone. These drugs further improved glomerular and tubular structural defects and impaired vasodilatory responses evoked by adenosinergic (N-ethylcarboxamidoadenosine) or cholinergic (acetylcholine) receptor activation in perfused kidneys of weaning dams. Likewise, treatment of weaning PE dams with a single 4-h dosing of lipopolysaccharides (LPS, 5 mg/kg) weakened renal structural damage, enhanced renal vasodilations and accentuated the upregulated vasodilatory response set off by losartan or pioglitazone. Molecularly, the favorable effect of pharmacologic or endotoxic intervention was coupled with dampened tubular and glomerular expressions of inflammatory (toll-like receptor 4) and apoptotic signals (caspase-3). Our data unveil beneficial and possibly intensified conditioning effect for endotoxemia when combined with losartan or pioglitazone against preeclamptic renovascular dysfunction and inflammation.

Iron and ferroptosis in kidney disease: molecular and metabolic mechanisms

Maintaining iron homeostasis is necessary for kidney functioning. There is more and more research indicating that kidney disease is often caused by iron imbalance. Over the past decade, ferroptosis' role in mediating the development and progression of renal disorders, such as acute kidney injury (renal ischemia-reperfusion injury, drug-induced acute kidney injury, severe acute pancreatitis induced acute kidney injury and sepsis-associated acute kidney injury), chronic kidney disease (diabetic nephropathy, renal fibrosis, autosomal dominant polycystic kidney disease) and renal cell carcinoma, has come into focus. Thus, knowing kidney iron metabolism and ferroptosis regulation may enhance disease therapy. In this review, we discuss the metabolic and molecular mechanisms of iron signaling and ferroptosis in kidney disease. We also explore the possible targets of ferroptosis in the therapy of renal illness, as well as their existing limitations and future strategies.

Methyltransferase-like 14 promotes ferroptosis in sepsis-induced acute kidney injury via increasing the m6A methylation modification of LPCAT3

Acute kidney injury (AKI) is one of the most serious and common complications in the course of sepsis, known for its poor prognosis and high mortality rate. Recently, ferroptosis, as a newly discovered regulatory cell death, might be closely associated with the progression of AKI. METTL14 is a writer of RNA m6A, an abundant epigenetic modification in transcriptome with broad function. Hence, the purpose of our study is to explore the potential function and mechanism of METTL14 on the ferroptosis in sepsis-induced AKI. In this paper, TCMK-1 cells and mice treated with LPS were used to constructe AKI model in vitro and in vivo. Pathological changes of renal tissue were observed by HE staining. The fluorescent probe C11-BODIPY and 4HNE kits were used to measure the lipid peroxidation. The ferroptosis index was evaluated by MDA, GSH and Fe2+ kits. The total m6A levels were analyzed by EpiQuik M6A RNA methylation kit, and the m6A levels of LPCAT3 were examined by Me-RIP assay. Finally, the interaction between LPCAT3 and METTL14 was clarified using RIP and dual-luciferase reporter gene assays. Our works revealed that the m6A level and ferroptosis was markedly ascended in LPS-induced TCMK-1 cells. The silence of METTL14 lowered the cell viability, the levels of MDA, Fe2+ and lipid peroxidation in the LPS-stimulated AKI model in vitro and in vivo, but increase GSH levels. Moreover, the up-regulation of ferroptosis-related proteins by LPS was notably inhibited by the knockdown of METTL14. In addition, silencing METTL14 reduced the m6A and mRNA levels of LPCAT3. Furthermore, the efficacy of METTL14 downregulation on the ferroptosis in the LPS-induced TCMK-1 cells were antagonized by LPCAT3 overexpression. Taken together, our findings revealed that METTL14 knockdown resisted ferroptosis in sepsis-induced AKI through lessening the level of LPCAT3 mediated by m6A modification.

Self-Assembled Pt/Honokiol Nanomicelles for the Treatment of Sepsis-Associated Acute Kidney Injury

Sepsis is a severe and complex systemic infection that can result in multiple organ dysfunction. Sepsis-associated acute kidney injury (SAKI), caused by inflammatory response, oxidative stress, and cellular apoptosis, is a common complication that seriously impacts patient survival rates. Herein, a potent and novel metal-polyphenol nanomicelle can be efficiently self-assembled with Pt4+ and honokiol (HK) by the chelation, π-π conjugation, hydrophobic action, and the surfactant properties of Tween-80. These nanomicelles not only enhance drug bioavailability (encapsulation rates: Pt─49%, HK─70%) and reduce drug toxicity (safety dose: <20 μg/g) but also improve targeting toward damaged renal tissues. Furthermore, Pt4+ and HK in the nanomicelles exert a synergistic physiological effect by scavenging free radicals to alleviate oxidative damage, inhibiting macrophage activation and the release of inflammatory factors to regulate inflammation, and displaying broad-spectrum antimicrobial activity to control infection. These actions collectively protect renal tissue and restore its functionality. Here, we constructed metal-polyphenol nanomicelles (Pt/HK-NMs) via ingenious and efficient self-assembly, providing a new strategy to compensate for deficiencies in the hemodialysis and antibiotic treatment of SAKI.

Neng-Jing-Huo Essential Oil Blend Inhibits Lipopolysaccharide-Induced Intracellular Reactive Oxygen Species Accumulation, Inflammation, and Apoptosis in Renal Tubular Epithelial Cells

ABSTRACT

Acute kidney injury (AKI) is a common serious complication of sepsis that is characterized by the rapid deterioration of kidney function. Neng-Jing-Huo (NJH) is an essential oil blend, including Gaultheria procumbens, Zingiber officinale, Bulnesia sarmientoi, Artemisia vulgaris , and Styrax benzoin oils, with antimicrobial, antioxidant, and anti-inflammatory activities. Here, we investigated the effects of NJH on oxidative stress, inflammatory response, and apoptosis in an in vitro septic AKI model and explored the underlying mechanisms. A cellular model of septic AKI was established using lipopolysaccharide (LPS). Cell viability was assessed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Action mechanisms of NJH were analyzed using the Griess reagent, 2',7'-dichlorodihydrofluorescein diacetate, 5,5',6,6' tetrachloro-1,1'3,3' tetraethylbenzimidazolcarbocyanine iodide, annexin V, caspase activity, western blotting, and semi-quantitative reverse transcription polymerase chain reaction assays. Results showed that pretreatment with NJH significantly improved cell survival and suppressed nitric oxide (NO) production in LPS-stimulated NRK-52E renal tubular epithelial cells. NJH also decreased the levels of intracellular reactive oxygen species and maintained the mitochondrial membrane potential by upregulating the nuclear factor (NF) erythroid 2-related factor 2/heme oxygenase-1 levels and downregulating the NADPH oxidase 4 levels. In addition, NJH suppressed the activation of the toll-like receptor 4/NF-κB and NLRP3/caspase-1 pathways, thereby decreasing the inflammatory response in LPS-stimulated NRK-52E cells. Moreover, NJH decreased the levels of Bax, caspase-9, and caspase-3 but increased those of Bcl-2, which led to a reduction in LPS-induced apoptosis. Overall, our findings revealed that NJH ameliorated LPS-induced damage in NRK-52E cells by inhibiting oxidative stress, inflammation, and apoptosis, highlighting its therapeutic potential for septic AKI.

Sepsis-Associated Acute Kidney Injury: What's New Regarding Its Diagnostics and Therapeutics?

Sepsis-associated acute kidney injury (SA-AKI) is defined as the development of AKI in the context of a potentially life-threatening organ dysfunction attributed to an abnormal immune response to infection. SA-AKI has been associated with increased mortality when compared to sepsis or AKI alone. Therefore, its early recognition is of the utmost importance in terms of its morbidity and mortality rates. The aim of this review is to shed light on the pathophysiological pathways implicated in SA-AKI as well as its diagnostics and therapeutics. In this review, we will elucidate upon serum and urinary biomarkers, such as creatinine, cystatin, neutrophil gelatinase-associated lipocalin (NGAL), proenkephalin A 119-159, interleukin-6, interleukin-8 and interleukin-18, soluble toll-like receptor 2 (sTLR2), chemokine ligand 2 (CCL2) and chemokine C-C-motif 14 (CCL14). In addition, the role of RNA omics as well as machine learning programs for the timely diagnosis of SA-AKI will be further discussed. Moreover, regarding SA-AKI treatment, we will elaborate upon potential therapeutic agents that are being studied, based on the pathophysiology of SA-AKI, in humans and in animal models.

Regulation of ubiquitination in sepsis: from PAMP versus DAMP to peripheral inflammation and cell death

Sepsis (sepsis) is a systemic inflammatory response triggered by infection, and its pathologic features include overproduction of peripheral inflammatory factors (e.g., IL-1β, IL-6, TNF-α), which ultimately leads to cytokine storm and multiple organ dysfunction syndrome (MODS). Pathogen-associated molecular patterns (PAMP) and damage-associated molecular patterns (DAMP) induce strong immune responses and exacerbate inflammation by activating pattern recognition receptors (PRRs) in the host. Ubiquitination, as a key protein post-translational modification, dynamically regulates the activity of several inflammation-associated proteins (e.g., RIPK1, NLRP3) through the coordinated action of the E1, E2, and E3 enzymes, affects cell death pathways such as necroptosis and pyroptosis, and ultimately regulates the release of peripheral inflammatory factors. Deubiquitinating enzymes (DUBs), on the other hand, influence the intensity of the inflammatory response in sepsis by counter-regulating the ubiquitination process and balancing pro- and anti-inflammatory signals. This review focuses on how PAMP and DAMP activate inflammatory pathways via PRRs, and the central role of ubiquitination and deubiquitination in the development of sepsis, especially the mechanisms in regulating the secretion of peripheral inflammatory factors and cell death. By deeply dissecting the impact of the balance of ubiquitination and deubiquitination on inflammatory regulation, we further envision its potential as a therapeutic target in sepsis.

EIF2AK2 protein targeted activation of AIM2-mediated PANoptosis promotes sepsis-induced acute kidney injury

BACKGROUND

Acute kidney injury (AKI) frequently occurs as a complication of sepsis. PANoptosis refers to a type of inflammatory programmed cell death that exhibits key characteristics of apoptosis, necroptosis, and pyroptosis. Here, we evaluated the role of absent in melanoma 2 (AIM2) and eukaryotic translation initiation factor 2 alpha kinase 2 (EIF2AK2) in septic AKI.

METHODS

A septic AKI model was created through cecal ligation and puncture (CLP), while an in vitro model was developed using lipopolysaccharide (LPS)-stimulated HK2 cells. Hematoxylin and eosin (HE), Periodic acid-Schiff (PAS), and TUNEL staining were conducted to assess kidney injury in mice. Levels of serum creatinine (Scr) and blood urea nitrogen (BUN) were detected by kits. Gene expression was detected utilizing RT-qPCR, and Western blot was used to test protein levels. Immunofluorescence was employed to measure EIF2AK2 and AIM2 expression in mouse kidney tissue. Lactate dehydrogenase (LDH) activity assay was conducted to evaluate cytotoxicity. Co-immunoprecipitation (Co-IP) was performed to verify the binding relationship between EIF2AK2 and AIM2.

RESULTS

AIM2 expression was increased in the renal tissue of mice subjected to CLP. Activation of the inflammasome and PANoptosis were observed in the renal tissue of CLP mice. AIM2 depletion attenuated PANoptosis in LPS-treated HK-2 cells. Additionally, EIF2AK2 could directly target AIM2, leading to a positive regulation of AIM2 expression. Notably, EIF2AK2 induced PANoptosis through upregulating AIM2 in HK-2 cells stimulated by LPS.

CONCLUSIONS

Our results revealed the important role of EIF2AK2-induced AIM2 upregulation in the activation of PANoptosis during septic AKI.

Fibronectin type III domain containing protein 5/irisin alleviated sepsis-induced acute kidney injury by abating ferroptosis through the adenosine 5'-monophosphate-activated protein kinase/nuclear factor erythroid-2-related factor 2 signaling pathway

Objective

Ferroptosis has been described in association with acute kidney injury (AKI)-induced sepsis. Fibronectin type III domain containing protein 5 (FNDC5)/irisin plays a crucial role in renal protection. The objective of this study was to investigate whether FNDC5/irisin is involved in AKI-induced sepsis by modulating ferroptosis, and the molecular mechanisms that may be involved.

Material and Methods

A sepsis-induced AKI model was built in vivo and in vitro through lipopolysaccharide (LPS) intervention. FNDC5, adenosine 5'-monophosphate-activated protein kinase (AMPK), phospho-AMPK (p-AMPK), nuclear factor erythroid-2-related factor 2 (Nrf2), heme oxygenase-1 (HO-1), glutathione peroxidase 4 (GPX4), and acyl-CoA synthetase long-chain family member 4 (ACSL4) concentrations in cells and mouse kidney tissues were appraised by Western blot. Pro-inflammatory cytokines concentrations in cell supernatants and mouse kidney tissues were appraised by enzyme-linked immunosorbent assay. Fe2+ concentration in cells and mouse kidney tissue was appraised by kit. The apoptosis rate of cells and mouse kidney tissue was measured by flow cytometry. Automatic biochemical analyzer was to test serum creatinine (SCr) and blood urea nitrogen (BUN). The kidney tissue sections from each groups were observed by hematoxylin and eosin staining.

Results

LPS abated FNDC5 concentration in human kidney-2 cells and mouse kidney tissue (P < 0.001). Overexpression of FNDC5 can abated proinflammatory cytokines concentrations in cells and mouse kidney tissue (P < 0.01). Meanwhile, overexpression of FNDC5 can boost GPX4 protein concentration, abate ACSL4 protein, and abate Fe2+ concentration in cells and mouse kidney tissues (P < 0.05). In addition, the overexpression of FNDC5 can reduce the rate of apoptosis (P < 0.01). In vivo experiments showed that FNDC5 overexpression reduced serum BUN and SCr concentrations and alleviated pathological damage in the mouse renal tissues (P < 0.05) and exhibited a certain renal protective effect. FNDC5 overexpression can boost p-AMPK/AMPK, Nrf2, and HO-1 protein concentrations (P < 0.01).

Conclusion

FNDC5/irisin improves sepsis-induced acute renal injury by abating ferroptosis through the AMPK/Nrf2 signaling pathway.

The impact of ulinastatin on lymphocyte apoptosis and autophagy in sepsis patients

This study aimed to assess the influence of ulinastatin (UTI) on lymphocyte apoptosis and autophagy in sepsis patients, as well as its effect on inflammatory factors and vital organ function, with the goal of providing insights for improved clinical management of sepsis. A total of 40 sepsis patients were randomly assigned to the UTI group or the control group. The UTI group received standard treatment plus intravenous UTI, while the control group received standard treatment alone. Peripheral blood samples were collected at multiple time points for analysis of lymphocyte apoptosis, autophagy, inflammatory markers, and organ function. Various experimental techniques including Hoechst staining, transmission electron microscopy, and Western blot analysis were utilized to assess lymphocyte apoptosis, autophagy, and related protein expression levels. The study revealed that UTI treatment significantly inhibited lymphocyte apoptosis and promoted autophagy in sepsis patients. The levels of autophagy-related proteins LC3-II and Beclin-1 were substantially elevated, while the ratio of anti-apoptotic Bcl-2 to pro-apoptotic Bax was increased following UTI treatment. Furthermore, the levels of inflammatory markers IL-6, procalcitonin, and C-reactive protein were markedly reduced in the UTI group compared to the control group. Additionally, UTI treatment led to improved liver, kidney and cardiac function as evidenced by reduced levels of liver enzymes and creatinine, and cardiac enzymes. The findings of this study demonstrate that UTI exerts a protective effect on septic patients by inhibiting lymphocyte apoptosis, promoting autophagy, and attenuating systemic inflammation. Moreover, UTI treatment was associated with improved liver, kidney, and cardiac function in septic patients. These results contribute to a better understanding of the clinical management of sepsis and underscore the potential of UTI as a therapeutic intervention in septic patients.

Human Umbilical Cord-Derived Mesenchymal Stem Cells-Exosomes-Delivered miR-375 Targets HDAC4 to Promote Autophagy and Suppress T Cell Apoptosis in Sepsis-Associated Acute Kidney Injury

This study sought to elucidate the mechanism of human umbilical cord-derived mesenchymal stem cells (HUCMSCs)-exosomes (Exos) in sepsis-associated acute kidney injury (SAKI). Exos were isolated from HUCMSCs and co-cultured with CD4+ T cells exposed to lipopolysaccharide to detect the effects of HUCMSCs-Exos on CD4+ T cell apoptosis and autophagy. miR-375 expression in CD4+ T cells and HUCMSCs-Exos was examined. The relationship between miR-375 and HDAC4 was analyzed. A mouse model of SAKI was established and injected with HUCMSCs-Exos to verify the function of HUCMSCs-Exos in vivo. HUCMSCs-Exos inhibited lipopolysaccharide-induced apoptosis of CD4+ T cells and promoted autophagy. miR-375 expression was noted to be elevated in the HUCMSCs-Exos. Importantly, HUCMSCs-Exos could deliver miR-375 into CD4+ T cells where miR-375 targeted HDAC4 and negatively regulated its expression. By this mechanism, HUCMSCs-Exos decreased CD4+ T cell apoptosis and augmented autophagy. This finding was further confirmed in an in vivo SAKI model. Collectively, HUCMSCs-Exos can protect against SAKI via delivering miR-375 that promotes autophagy and arrests T cell apoptosis through HDAC4 downregulation. These findings suggest a promising therapeutic potential for HUCMSCs-Exos in the context of SAKI.

Caspase-8 in inflammatory diseases: a potential therapeutic target

Caspase-8, a renowned cysteine-aspartic protease within its enzyme family, initially garnered attention for its regulatory role in extrinsic apoptosis. With advancing research, a growing body of evidence has substantiated its involvement in other cell death processes, such as pyroptosis and necroptosis, as well as its modulatory effects on inflammasomes and proinflammatory cytokines. PANoptosis, an emerging concept of cell death, encompasses pyroptosis, apoptosis, and necroptosis, providing insight into the often overlapping cellular mortality observed during disease progression. The activation or deficiency of caspase-8 enzymatic activity is closely linked to PANoptosis, positioning caspase-8 as a key regulator of cell survival or death across various physiological and pathological processes. Aberrant expression of caspase-8 is closely associated with the development and progression of a range of inflammatory diseases, including immune system disorders, neurodegenerative diseases (NDDs), sepsis, and cancer. This paper delves into the regulatory role and impact of caspase-8 in these conditions, aiming to elucidate potential therapeutic strategies for the future intervention.

Thinking Induced by Acute Kidney Injury of Diquat Poisoning: Cases Report

Diquat poisoning is a fatal condition that is becoming increasingly common. The mortality risk of patients taking lethal doses of diquat is extremely high. It typically leads to rapid dysfunction of multiple organs, including the kidneys, heart, lungs, and brain. Acute kidney injury is usually the first manifestation of this poisoning. However, the optimal treatment strategy for diquat poisoning remains uncertain. Additionally, the mechanism of multiple organ dysfunction syndrome caused by diquat poisoning may resemble the progression of sepsis. In this report, we present 3 cases of diquat poisoning, all of which resulted in death. We emphasize that acute kidney injury is the primary cause of death, and suggest that some strategies used in the treatment of sepsis could be beneficial in managing diquat poisoning-induced acute kidney injury.

Classification and functional analysis of disulfidptosis-associated genes in sepsis

Sepsis represents a critical condition characterized by multiple-organ dysfunction resulting from inflammatory response to infection. Disulfidptosis is a newly identified type of programmed cell death that is intimately associated with the actin cytoskeleton collapse caused by glucose starvation and disulfide stress, but its role in sepsis is largely unknown. The study was to adopt a diagnostic and prognostic signature for sepsis with disulfidptosis based on the differentially expressed genes (DEGs) between sepsis and healthy people from GEO database. The disulfidptosis hub genes associated with sepsis were identified, and then developed consensus clustering and immune infiltration characteristics. Next, we evaluated disulfidptosis-related risk genes by using LASSO and Random Forest algorithms, and constructed the diagnostic sepsis model by nomogram. Finally, immune infiltration, GSVA analysis and mRNA-miRNA networks based on disulfidptosis-related DEGs were screened. There are five upregulated disulfidptosis-related genes and seven downregulated genes were filtered out. The six intersection disulfidptosis-related genes including LRPPRC, SLC7A11, GLUT, MYH9, NUBPL and GYS1 exhibited higher predictive ability for sepsis with an accuracy of 99.7%. In addition, the expression patterns of the critical genes were validated. The study provided a comprehensive view of disulfidptosis-based signatures to predict the prognosis, biological features and potential treatment directions for sepsis.

Myricitrin inhibited ferritinophagy-mediated ferroptosis in cisplatin-induced human renal tubular epithelial cell injury

Cisplatin-induced acute kidney injury (AKI) increases the patient mortality dramatically and results in an unfavorable prognosis. A strong correlation between AKI and ferroptosis, which is a notable type of programmed cell death, was found in recent studies. Myricitrin is a natural flavonoid compound with diverse pharmacological properties. To investigate the protective effect of myricitrin against cisplatin induced human tubular epithelium (HK-2) cell injury and the underlying anti-ferroptic mechanism by this study. Firstly, a pharmacology network analysis was proposed to explore the myricitrin's effect. HK-2 cells were employed for in vitro experiments. Ferroptosis was detected by cell viability, quantification of iron, malondialdehyde, glutathione, lipid peroxidation fluorescence, and glutathione peroxidase (GPX4) expression. Ferritinophagy was detected by related protein expression (NCOA4, FTH, LC3II/I, and SQSTM1). In our study, GO enrichment presented that myricitrin might be effective in eliminating ferroptosis. The phenomenon of ferroptosis regulated by ferritinophagy was observed in cisplatin-activated HK-2 cells. Meanwhile, pretreatment with myricitrin significantly rescued HK-2 cells from cell death, reduced iron overload and lipid peroxidation biomarkers, and improved GPX4 expression. In addition, myricitrin downregulated the expression of LC3II/LC3I and NCOA4 and elevated the expression of FTH and SQTM. Furthermore, myricitrin inhibited ROS production and preserved mitochondrial function with a lower percentage of green JC-1 monomers. However, the protection could be reserved by the inducer of ferritinophagy rapamycin. Mechanically, the Hub genes analysis reveals that AKT and NF-κB are indispensable mediators in the anti-ferroptic process. In conclusion, myricitrin ameliorates cisplatin induced HK-2 cells damage by attenuating ferritinophagy mediated ferroptosis.

Histone deacetylase-mediated silencing of PSTPIP2 expression contributes to aristolochic acid nephropathy-induced PANoptosis

BACKGROUND AND PURPOSE

Aristolochic acid nephropathy (AAN) is a progressive kidney disease caused by using herbal medicines. Currently, no therapies are available to treat or prevent aristolochic acid nephropathy. Histone deacetylase (HDAC) plays a crucial role in the development and progression of renal disease. We tested whether HDAC inhibitors could prevent aristolochic acid nephropathy and determined the underlying mechanism.

EXPERIMENTAL APPROACH

HDACs expression in the aristolochic acid nephropathy model was examined. The activation of PANoptosis of mouse kidney and renal tubular epithelial cell were assessed after exposure to HDAC1 and HDAC2 blockade. Kidney-specific knock-in of proline-serine-threonine-phosphatase-interacting protein 2 (PSTPIP2) mice were used to investigate whether PSTPIP2 affected the production of PANoptosome.

KEY RESULTS

Aristolochic acid upregulated the expression of HDAC1 and HDAC2 in the kidneys. Notably, the HDAC1 and HDAC2 specific inhibitor, romidepsin (FK228, depsipeptide), suppressed aristolochic acid-induced kidney injury, epithelial cell pyroptosis, apoptosis and necroptosis (PANoptosis). Moreover, romidepsin upregulated PSTPIP2 in renal tubular epithelial cells, which was enhanced by aristolochic acid treatment. Conditional knock-in of PSTPIP2 in the kidney protected against aristolochic acid nephropathy. In contrast, the knockdown of PSTPIP2 expression in PSTPIP2-knock-in mice restored kidney damage and PANoptosis. PSTPIP2 function was determined in vitro using PSTPIP2 knockdown or overexpression in mouse renal tubular epithelial cells (mTECs). Additionally, PSTPIP2 was found to regulate caspase 8 in aristolochic acid nephropathy.

CONCLUSION AND IMPLICATIONS

HDAC-mediated silencing of PSTPIP2 may contribute to aristolochic acid nephropathy. Hence, HDAC1 and HDAC2 specific inhibitors or PSTPIP2 could be valuable therapeutic agents for preventing aristolochic acid nephropathy.

Elevated Activated Partial Thromboplastin Time as a Predictor of 28-Day Mortality in Sepsis-Associated Acute Kidney Injury: A Retrospective Cohort Analysis

Purpose

To address the critical mortality rates among sepsis-associated acute kidney injury (SA-AKI) patients, early prognosis is vital. This study investigates the relationship between coagulation indices and the 28-day mortality rate in patients with SA-AKI.

Patients and Methods

This study was a retrospective cohort analysis including patients with SA-AKI admitted to the First Hospital of Fujian Medical University as a training cohort (n = 119) and patients admitted to the Third People's Hospital of Fujian University of Traditional Chinese Medicine as a validation cohort (n = 51). We examined the relationship between coagulation indices and 28-day mortality in SA-AKI, the cumulative mortality at different activated partial thromboplastin time (APTT) levels, and the nonlinear relationship between APTT and 28-day mortality. Receiver operating characteristic curves were plotted, and the area under the curve was calculated to assess the predictive power of APTT. Finally, subgroup analyses were performed to assess the robustness of the association.

Results

Overall, 119 participants with a mean±standard deviation age of 70.47±15.20 years were included in the training cohort: 54 died, 65 survived. According to univariate and multivariate COX regression analyses, APACHE II score, CRP level, Lac level, and APTT level were independent risk factors for 28-day adverse prognosis. After controlling for some variables, an elevated baseline APTT (≥ 37.7 s) was associated with an elevated risk of 28-day mortality (HR, 1.017; 95% CI, 1.001-1.032), and Kaplan-Meier analyses further confirmed the increased mortality in the group with a higher APTT. The same results were shown when the validation cohort was analyzed (HR, 1.024; 95% CI, 0.958-1.096). Subgroup analyses showed the stability of the association between APTT and poor prognosis in SA-AKI.

Conclusion

In essence, APTT elevation is synonymous with increased 28-day mortality rates, indicating a poor prognosis in SA-AKI scenarios.

Pyroptosis: The Determinator of Cell Death and Fate in Acute Kidney Injury

Background

Acute kidney injury (AKI) is kidney damage that leads to a rapid decline in function. AKI primarily occurs when the tubular epithelium is damaged, causing swelling, loss of brush margin, and eventual apoptosis. Research has shown that tubular epithelial cell damage in AKI is linked to cell cycle arrest, autophagy, and regulation of cell death.

Summary

Pyroptosis, a type of programmed cell death triggered by inflammation, is believed to play a role in the pathophysiology of AKI. Cumulative evidence has shown that pyroptosis is the main cause of tubular cell death in AKI. Thus, targeted intervention of pyroptosis may be a promising therapeutic approach for AKI. This review delves deep into the cutting-edge research surrounding pyroptosis in the context of AKI, shedding light on its intricate mechanisms and potential implications for clinical practice. Additionally, we explore the exciting realm of potential preclinical treatment options for AKI, aiming to pave the way for future therapeutic advancements.

Key Messages

Pyroptosis, a highly regulated form of cell death, plays a crucial role in determining the fate of cells during the development of AKI. This intricate process involves the activation of inflammasomes, which are multi-protein complexes that initiate pyroptotic cell death. By understanding the mechanisms underlying pyroptosis, researchers aim to gain insights into the pathogenesis of AKI and potentially identify new therapeutic targets for this condition.

Sepsis-Associated Acute Kidney Injury: Where Are We Now?

Worldwide, sepsis is a well-recognized cause of death. Acute kidney injury (AKI) may be related to sepsis in up to 70% of AKI cases. Sepsis-associated AKI (SA-AKI) is defined as the presence of AKI according to the Kidney Disease: Improving Global Outcomes criteria in the context of sepsis. SA-AKI is categorized into early, which presents during the first 48 h of sepsis, and late, presenting between 48 h and 7 days of sepsis. SA-AKI is associated with a worse prognosis among patients with sepsis. However, there are different SA-AKI phenotypes as well as different pathophysiological pathways of SA-AKI. The aim of this review is to provide an updated synopsis of the pathogenetic mechanisms underlying the development of SA-AKI as well as to analyze its different phenotypes and prognosis. In addition, potential novel diagnostic and prognostic biomarkers as well as therapeutic approaches are discussed. A plethora of mechanisms are implicated in the pathogenesis of SA-AKI, including inflammation and metabolic reprogramming during sepsis; various types of cell death such as apoptosis, necroptosis, pyroptosis and ferroptosis; autophagy and efferocytosis; and hemodynamic changes (macrovascular and microvascular dysfunction). Apart from urine output and serum creatinine levels, which have been incorporated in the definition of AKI, several serum and urinary diagnostic and prognostic biomarkers have also been developed, comprising, among others, interleukins 6, 8 and 18, osteoprotegerin, galectin-3, presepsin, cystatin C, NGAL, proenkephalin A, CCL-14, TIMP-2 and L-FABP as well as biomarkers stemming from multi-omics technologies and machine learning algorithms. Interestingly, the presence of long non-coding RNAs (lncRNAs) as well as microRNAs (miRNAs), such as PlncRNA-1, miR-22-3p, miR-526b, LncRNA NKILA, miR-140-5p and miR-214, which are implicated in the pathogenesis of SA-AKI, may also serve as potential therapeutic targets. The combination of omics technologies represents an innovative holistic approach toward providing a more integrated view of the molecular and physiological events underlying SA-AKI as well as for deciphering unique and specific phenotypes. Although more evidence is still necessary, it is expected that the incorporation of integrative omics may be useful not only for the early diagnosis and risk prognosis of SA-AKI, but also for the development of potential therapeutic targets that could revolutionize the management of SA-AKI in a personalized manner.

Connexin32 gap junction channels deliver miR155-3p to mediate pyroptosis in renal ischemia-reperfusion injury

OBJECTIVES

To explore whether the gap junction (GJ) composed by connexin32(Cx32) mediated pyroptosis in renal ischemia-reperfusion(I/R) injury via transmitting miR155-3p, with aim to provide new strategies for the prevention and treatment of acute kidney injury (AKI) after renal I/R.

METHODS

8-10 weeks of male C57BL/ 6 wild-type mice and Cx32 knockdown mice were divided into two groups respectively: control group and renal I/R group. MCC950 (50 mg/kg. ip.) was used to inhibit NLRP3 in vivo. Human kidney tubular epithelial cells (HK - 2) and rat kidney tubular epithelial cells (NRK-52E) were divided into high-density group and low-density group, and treated with hypoxia reoxygenation (H/R) to mimic I/R. The siRNA and plasmid of Cx32, mimic and inhibitor of miR155-3p were transfected into HK - 2 cells respectively. Kidney pathological and functional injuries were measured. Western Blot and immunofluorescent staining were used to observe the expression of NLRP3, GSDMD, GSDMD-N, IL - 18, and mature IL-18. The secretion of IL-18 and IL-1β in serum, kidney tissue and cells supernatant were detected by enzyme-linked immuno sorbent assay (ELISA) kit, and the expression of NLPR3 and miR155-3p were detected by RT-qPCR and fluorescence in situ hybridization (FISH).

RESULTS

Tubular pyroptosis were found to promote AKI after I/R in vivo and Cx32-GJ regulated pyroptosis by affecting the expression of miR155-3p after renal I/R injury. In vitro, H/R could lead to pyroptosis in HK-2 and NRK-52E cells. When the GJ channels were not formed, and Cx32 was inhibited or knockdown, the expression of miR155-3p was significantly reduced and the pyroptosis was obviously inhibited, leading to the reduction of injury and the increase of survival rate. Moreover, regulating the level of miR155-3p could affect survival rate and pyroptosis in vitro after H/R.

CONCLUSIONS

The GJ channels composed of Cx32 regulated tubular pyroptosis in renal I/R injury by transmitting miR155-3p. Inhibition of Cx32 could reduce the level of miR155-3p further to inhibit pyroptosis, leading to alleviation of renal I/R injury which provided a new strategy for preventing the occurrence of AKI. Video Abstract.

Association between red cell distribution width to albumin ratio and acute kidney injury in patients with sepsis: a MIMIC population-based study

PURPOSE

To investigate the association between red cell distribution width (RDW) to albumin (ALB) ratio and acute kidney injury (AKI) in sepsis.

METHODS

This was a retrospective cohort study. Data were collected from the Medical Information Mart for Intensive Care Database IV (MIMIC-IV) from 2008 to 2019. The incidence of AKI was the primary outcome, which was defined based on the improving Global Outcomes (KDIGO). The association of RDW/ALB ratio with AKI in sepsis was assessed by multivariate logistic regression analysis using relative risk (RR) and a 95% confidence interval (CI). Subgroup group analyses were applied according to age, use of ventilation, and use of vasopressor, SAPS II, and SOFA.

RESULTS

Of 1810 sepsis patients involved in this study, 563 (31.10%) sepsis patients developed AKI after ICU admission. The results suggested an increase in RDW/ALB was associated with a rise in the risk of AKI in sepsis (RR 1.09, 95% CI 1.02 to 1.16, P = 0.013).Based on the subgroup analysis, RDW/ALB ratio was significantly associated with the risk of AKI in sepsis patients using the treatment of ventilation (RR: 1.07, 95% CI 1.01 to 1.14, P = 0.041)) and in patients with SAPS II < 43 (RR: 1.16, 95% CI 1.04 to 1.29, P = 0.007).

CONCLUSION

RDW/ALB ratio was independently associated with the risk of AKI in sepsis patients.

CHIP protects against septic acute kidney injury by inhibiting NLRP3-mediated pyroptosis

Septic acute kidney injury (S-AKI), the most common type of acute kidney injury (AKI), is intimately related to pyroptosis and oxidative stress in its pathogenesis. Carboxy-terminus of Hsc70-interacting protein (CHIP), a U-box E3 ligase, modulates oxidative stress by degrading its targeted proteins. The role of CHIP in S-AKI and its relevance with pyroptosis have not been investigated. In this study, we showed that CHIP was downregulated in renal proximal tubular cells in lipopolysaccharide (LPS)-induced S-AKI. Besides, the extent of redox injuries in S-AKI was attenuated by CHIP overexpression or activation but accentuated by CHIP gene disruption. Mechanistically, our work demonstrated that CHIP interacted with and ubiquitinated NLRP3 to promote its proteasomal degradation, leading to the inhibition of NLRP3/ACS inflammasome-mediated pyroptosis. In summary, this study revealed that CHIP ubiquitinated NLRP3 to alleviate pyroptosis in septic renal injuries, suggesting that CHIP might be a potential therapeutic target for S-AKI.

Nlrp3 Deficiency Alleviates Lipopolysaccharide-Induced Acute Kidney Injury via Suppressing Renal Inflammation and Ferroptosis in Mice

The nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) inflammasome is a vital component of many inflammatory responses. Here, we intended to investigate the involvement of NLRP3 in lipopolysaccharide (LPS)-induced sepsis-associated acute kidney injury (S-AKI) and explore its mechanisms. For the first time, we validated elevated NLRP3 expression in the renal tissues of S-AKI patients by immunohistochemistry analysis. Through LPS injection in both wild-type and Nlrp3-/- mice, a S-AKI model was developed. It was found that LPS-induced kidney injury, including an abnormal morphology in a histological examination, abnormal renal function in a laboratory examination, and an increase in the expression of AKI biomarkers, was dramatically reversed in Nlrp3-deficient mice. Nlrp3 deletion alleviated renal inflammation, as evidenced by the suppression of the expression of pro-inflammatory cytokines and chemokines. A combinative analysis of RNA sequencing and the FerrDb V2 database showed that Nlrp3 knockout regulated multiple metabolism pathways and ferroptosis in LPS-induced S-AKI. Further qPCR coupled with Prussian blue staining demonstrated that Nlrp3 knockout inhibited murine renal ferroptosis, indicating a novel mechanism involving S-AKI pathogenesis by NLRP3. Altogether, the aforementioned findings suggest that Nlrp3 deficiency alleviates LPS-induced S-AKI by reducing renal inflammation and ferroptosis. Our data highlight that NLRP3 is a potential therapeutic target for S-AKI.

Identification of potential necroinflammation-associated necroptosis-related biomarkers for delayed graft function and renal allograft failure: a machine learning-based exploration in the framework of predictive, preventive, and personalized medicine

Delayed graft function (DGF) is one of the key post-operative challenges for a subset of kidney transplantation (KTx) patients. Graft survival is significantly lower in recipients who have experienced DGF than in those who have not. Assessing the risk of chronic graft injury, predicting graft rejection, providing personalized treatment, and improving graft survival are major strategies for predictive, preventive, and personalized medicine (PPPM/3PM) to promote the development of transplant medicine. However, since PPPM aims to accurately identify disease by integrating multiple omics, current methods to predict DGF and graft survival can still be improved. Renal ischemia/reperfusion injury (IRI) is a pathological process experienced by all KTx recipients that can result in varying occurrences of DGF, chronic rejection, and allograft failure depending on its severity. During this process, a necroinflammation-mediated necroptosis-dependent secondary wave of cell death significantly contributes to post-IRI tubular cell loss. In this article, we obtained the expression matrices and corresponding clinical data from the GEO database. Subsequently, nine differentially expressed necroinflammation-associated necroptosis-related genes (NiNRGs) were identified by correlation and differential expression analysis. The subtyping of post-KTx IRI samples relied on consensus clustering; the grouping of prognostic risks and the construction of predictive models for DGF (the area under the receiver operating characteristic curve (AUC) of the internal validation set and the external validation set were 0.730 and 0.773, respectively) and expected graft survival after a biopsy (the internal validation set's 1-year AUC: 0.770; 2-year AUC: 0.702; and 3-year AUC: 0.735) were based on the least absolute shrinkage and selection operator regression algorithms. The results of the immune infiltration analysis showed a higher infiltration abundance of myeloid immune cells, especially neutrophils, macrophages, and dendritic cells, in the cluster A subtype and prognostic high-risk groups. Therefore, in the framework of PPPM, this work provides a comprehensive exploration of the early expression landscape, related pathways, immune features, and prognostic impact of NiNRGs in post-KTx patients and assesses their capabilities as.predictors of post-KTx DGF and graft loss,targets of the vicious loop between regulated tubular cell necrosis and necroinflammation for targeted secondary and tertiary prevention, andreferences for personalized immunotherapy.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13167-023-00320-w.

Epigenetic dysregulation of autophagy in sepsis-induced acute kidney injury: the underlying mechanisms for renoprotection

Sepsis-induced acute kidney injury (SI-AKI), a common critically ill, represents one of the leading causes of global death. Emerging evidence reveals autophagy as a pivotal modulator of SI-AKI. Autophagy affects the cellular processes of renal lesions, including cell death, inflammation, and immune responses. Herein, we conducted a systematic and comprehensive review on the topic of the proposed roles of autophagy in SI-AKI. Forty-one relevant studies were finally included and further summarized and analyzed. This review revealed that a majority of included studies (24/41, 58.5%) showed an elevation of the autophagy level during SI-AKI, while 22% and 19.5% of the included studies reported an inhibition and an elevation at the early stage but a declination of renal autophagy in SI-AKI, respectively. Multiple intracellular signaling molecules and pathways targeting autophagy (e.g. mTOR, non-coding RNA, Sirtuins family, mitophagy, AMPK, ROS, NF-Kb, and Parkin) involved in the process of SI-AKI, exerting multiple biological effects on the kidney. Multiple treatment modalities (e.g. small molecule inhibitors, temsirolimus, rapamycin, polydatin, ascorbate, recombinant human erythropoietin, stem cells, Procyanidin B2, and dexmedetomidine) have been found to improve renal function, which may be attributed to the elevation of the autophagy level in SI-AKI. Though the exact roles of autophagy in SI-AKI have not been well elucidated, it may be implicated in preventing SI-AKI through various molecular pathways. Targeting the autophagy-associated proteins and pathways may hint towards a new prospective in the treatment of critically ill patients with SI-AKI, but more preclinical studies are still warranted to validate this hypothesis.

Exploring the Metabolic Differences between Cisplatin- and UV Light-Induced Apoptotic Bodies in HK-2 Cells by an Untargeted Metabolomics Approach

Among the extracellular vesicles, apoptotic bodies (ABs) are only formed during the apoptosis and perform a relevant role in the pathogenesis of different diseases. Recently, it has been demonstrated that ABs from human renal proximal tubular HK-2 cells, either induced by cisplatin or by UV light, can lead to further apoptotic death in naïve HK-2 cells. Thus, the aim of this work was to carry out a non-targeted metabolomic approach to study if the apoptotic stimulus (cisplatin or UV light) affects in a different way the metabolites involved in the propagation of apoptosis. Both ABs and their extracellular fluid were analyzed using a reverse-phase liquid chromatography-mass spectrometry setup. Principal components analysis showed a tight clustering of each experimental group and partial least square discriminant analysis was used to assess the metabolic differences existing between these groups. Considering the variable importance in the projection values, molecular features were selected and some of them could be identified either unequivocally or tentatively. The resulting pathways indicated that there are significant, stimulus-specific differences in metabolites abundancies that may propagate apoptosis to healthy proximal tubular cells; thus, we hypothesize that the share in apoptosis of these metabolites might vary depending on the apoptotic stimulus.

Role of microRNAs in programmed cell death in renal diseases: A review

MicroRNAs (miRNAs) regulate gene expression involving kidney morphogenesis and cell proliferation, apoptosis, differentiation, migration, invasion, immune evasion, and extracellular matrix remodeling. Programmed cell death (PCD) is mediated and regulated by specific genes and a wealth of miRNAs, which participate in various pathological processes. Dysregulation of miRNAs can disrupt renal development and induce the onset and progression of various renal diseases. An in-depth understanding of how miRNAs regulate renal development and diseases is indispensable to comprehending how they can be used in new diagnostic and therapeutic approaches. However, the mechanisms are still insufficiently investigated. Hence, we review the current roles of miRNA-related signaling pathways and recent advances in PCD research and aim to display the potential crosstalk between miRNAs and PCD. The prospects of miRNAs as novel biomarkers and therapeutic targets are also described, which might provide some novel ideas for further studies.

Depletion of PSMD14 suppresses bladder cancer proliferation by regulating GPX4

Objective

The aim of this study was to investigate the role of deubiquitinase (DUB) 26S proteasome non-ATPase regulatory subunit 14 (PSMD14) in patients with bladder cancer.

Methods

From 2016 to 2018, 181 patients diagnosed with primary bladder cancer at the Affiliated Hospital of Qingdao University were recruited. The expression of PSMD14 in bladder cancer tissues was tested by immunochemistry. The association between PSMD14 expression and clinical and pathological data and outcomes of bladder cancer patients was determined. Overexpression and knockdown cells were constructed to evaluate the effects of PSMD14 on proliferation of bladder cancer cells.

Results

Our results showed that PSMD14 was significantly overexpressed in bladder cancer tissues compared to adjacent non-tumor tissues (76.24% vs 23.76%, P = 0.02). The expression of PSMD14 was significantly higher in patients with larger tumor diameters (85.14% vs 70.09%, P = 0.019) and patients with a family history of cancer (92.16% vs 70.00%, P = 0.002). Patients with high expression of PSMD14 had poor disease-free survival (DFS) (HR = 2.89, 95% CI [1.247-6.711], P = 0.013). Gain and loss of function experiments demonstrated that PSMD14 deficiency inhibited bladder cancer cell proliferation. Additionally, depletion of PSMD14 suppressed bladder cancer cell growth via down-regulation of GPX4, and the promotion of PSMD14-induced cell growth was observably reversed by the GPX4 inhibitor RSL3.

Conclusion

We determined that PSMD14 is highly expressed in bladder cancer tissues, and that PSMD14 expression correlated with poor disease-free survival. Depletion of PSMD14 could inhibit the proliferation of bladder cancer cells through the downregulation of GPX4. Therefore, PSMD14 may be an effective target for the treatment of bladder cancer.

Circular RNA protein tyrosine kinase 2 aggravates pyroptosis and inflammation in septic lung tissue by promoting microRNA-766/eukaryotic initiation factor 5A axis-mediated ATP efflux

PURPOSE

Sepsis is characterized by an acute inflammatory response to infection, often with multiple organ failures, especially severe lung injury. This study was implemented to probe circular RNA (circRNA) protein tyrosine kinase 2 (circPTK2)-associated regulatory mechanisms in septic acute lung injury (ALI).

METHODS

A cecal ligation and puncture-based mouse model and an lipopolysaccharides (LPS)-based alveolar type II cell (RLE-6TN) model were generated to mimic sepsis. In the two models, inflammation- and pyroptosis-related genes were measured.

RESULTS

The degree of lung injury in mice was analyzed by hematoxylin and eosin (H&E) staining and the apoptosis was by terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling staining. In addition, pyroptosis and toxicity were detected in cells. Finally, the binding relationship between circPTK2, miR-766, and eukaryotic initiation factor 5A (eIF5A) was detected. Data indicated that circPTK2 and eIF5A were up-regulated and miR-766 was down-regulated in LPS-treated RLE-6TN cells and lung tissue of septic mice. Lung injury in septic mice was ameliorated after inhibition of circPTK2.

CONCLUSIONS

It was confirmed in the cell model that knockdown of circPTK2 effectively ameliorated LPS-induced ATP efflux, pyroptosis, and inflammation. Mechanistically, circPTK2 mediated eIF5A expression by competitively adsorbing miR-766. Taken together, circPTK2/miR-766/eIF5A axis ameliorates septic ALI, developing a novel therapeutic target for the disease.

Combination of machine learning-based bulk and single-cell genomics reveals necroptosis-related molecular subtypes and immunological features in autism spectrum disorder

Background

Necroptosis is a novel form of controlled cell death that contributes to the progression of various illnesses. Nonetheless, the function and significance of necroptosis in autism spectrum disorders (ASD) remain unknown and require further investigation.

Methods

We utilized single-nucleus RNA sequencing (snRNA-seq) data to assess the expression patterns of necroptosis in children with autism spectrum disorder (ASD) based on 159 necroptosis-related genes. We identified differentially expressed NRGs and used an unsupervised clustering approach to divide ASD children into distinct molecular subgroups. We also evaluated immunological infiltrations and immune checkpoints using the CIBERSORT algorithm. Characteristic NRGs, identified by the LASSO, RF, and SVM-RFE algorithms, were utilized to construct a risk model. Moreover, functional enrichment, immune infiltration, and CMap analysis were further explored. Additionally, external validation was performed using RT-PCR analysis.

Results

Both snRNA-seq and bulk transcriptome data demonstrated a greater necroptosis score in ASD children. Among these cell subtypes, excitatory neurons, inhibitory neurons, and endothelials displayed the highest activity of necroptosis. Children with ASD were categorized into two subtypes of necroptosis, and subtype2 exhibited higher immune activity. Four characteristic NRGs (TICAM1, CASP1, CAPN1, and CHMP4A) identified using three machine learning algorithms could predict the onset of ASD. Nomograms, calibration curves, and decision curve analysis (DCA) based on 3-NRG have been shown to have clinical benefit in children with ASD. Furthermore, necroptosis-based riskScore was found to be positively associated with immune activation. Finally, RT-PCR demonstrated differentially expressed of these four NRGs in human peripheral blood samples.

Conclusion

A comprehensive identification of necroptosis may shed light on the underlying pathogenic process driving ASD onset. The classification of necroptosis subtypes and construction of a necroptosis-related risk model may yield significant insights for the individualized treatment of children with ASD.

Update on Innate Immunity in Acute Kidney Injury—Lessons Taken from COVID-19

The serious clinical course of SARS-CoV-2 infection is usually accompanied by acute kidney injury (AKI), worsening prognosis and increasing mortality. AKI in COVID-19 is above all a consequence of systemic dysregulations leading to inflammation, thrombosis, vascular endothelial damage and necrosis. All these processes rely on the interactions between innate immunity elements, including circulating blood cells, resident renal cells, their cytokine products, complement systems, coagulation cascades and contact systems. Numerous simultaneous pathways of innate immunity should secure an effective host defense. Since they all form a network of cross-linked auto-amplification loops, uncontrolled activation is possible. When the actions of selected pathways amplify, cascade activation evades control and the propagation of inflammation and necrosis worsens, accompanied by complement overactivity and immunothrombosis. The systemic activation of innate immunity reaches the kidney, where the damage affecting single tubular cells spreads through tissue collateral damage and triggers AKI. This review is an attempt to synthetize the connections between innate immunity components engaged in COVID-19-related AKI and to summarize the knowledge on the pathophysiological background of processes responsible for renal damage.