Inhibiting NLRP3 inflammasome attenuates apoptosis in contrast-induced acute kidney injury through the upregulation of HIF1A and BNIP3-mediated mitophagy

Mitophagy in acute central nervous system injuries: regulatory mechanisms and therapeutic potentials

Acute central nervous system injuries, including ischemic stroke, intracerebral hemorrhage, subarachnoid hemorrhage, traumatic brain injury, and spinal cord injury, are a major global health challenge. Identifying optimal therapies and improving the long-term neurological functions of patients with acute central nervous system injuries are urgent priorities. Mitochondria are susceptible to damage after acute central nervous system injury, and this leads to the release of toxic levels of reactive oxygen species, which induce cell death. Mitophagy, a selective form of autophagy, is crucial in eliminating redundant or damaged mitochondria during these events. Recent evidence has highlighted the significant role of mitophagy in acute central nervous system injuries. In this review, we provide a comprehensive overview of the process, classification, and related mechanisms of mitophagy. We also highlight the recent developments in research into the role of mitophagy in various acute central nervous system injuries and drug therapies that regulate mitophagy. In the final section of this review, we emphasize the potential for treating these disorders by focusing on mitophagy and suggest future research paths in this area.

Protective effect and mechanism of Xiaoyu Xiezhuo decoction on ischemia-reperfusion induced acute kidney injury based on gut-kidney crosstalk

This study aimed to explore the mechanism of Xiaoyu Xiezhuo decoction (XXD) on ischemia-reperfusion-induced acute kidney injury (IRI-AKI) using network pharmacology methods and gut microbiota analysis. A total of 1778 AKI-related targets were obtained, including 140 targets possibly regulated by AKI in XXD, indicating that the core targets were mainly enriched in inflammatory-related pathways, such as the IL-17 signaling pathway and TNF signaling pathway. The unilateral IRI-AKI animal model was established and randomly divided into four groups: the sham group, the AKI group, the sham + XXD group, and the AKI + XXD group. Compared with the rats in the AKI group, XXD improved not only renal function, urinary enzymes, and biomarkers of renal damage such as Kim-1, cystatin C, and serum inflammatory factors such as IL-17, TNF-α, IL-6, and IL 1-β, but also intestinal metabolites including lipopolysaccharides, d-lactic acid, indoxyl sulfate, p-cresyl sulfate, and short-chain fatty acids. XXD ameliorated renal and colonic pathological injury as well as inflammation and chemokine gene abundance, such as IL-17, TNF-α, IL-6, IL-1β, ICAM-1, and MCP-1, in AKI rats via the TLR4/NF-κB/NLRP3 pathway, reducing the AKI score, renal pathological damage, and improving the intestinal mucosa's inflammatory infiltration. It also repaired markers of the mucosal barrier, including claudin-1, occludin, and ZO-1. Compared with the rats in the AKI group, the α diversity was significantly increased, and the Chao1 index was significantly enhanced after XXD treatment in both the sham group and the AKI group. The treatment group significantly reversed this change in microbiota.

Mitochondrial dysfunction in acute kidney injury

Acute kidney injury (AKI) is a systemic clinical syndrome increasing morbidity and mortality worldwide in recent years. Renal tubular epithelial cells (TECs) death caused by mitochondrial dysfunction is one of the pathogeneses. The imbalance of mitochondrial quality control is the main cause of mitochondrial dysfunction. Mitochondrial quality control plays a crucial role in AKI. Mitochondrial quality control mechanisms are involved in regulating mitochondrial integrity and function, including antioxidant defense, mitochondrial quality control, mitochondrial DNA (mtDNA) repair, mitochondrial dynamics, mitophagy, and mitochondrial biogenesis. Currently, many studies have used mitochondrial dysfunction as a targeted therapeutic strategy for AKI. Therefore, this review aims to present the latest research advancements on mitochondrial dysfunction in AKI, providing a valuable reference and theoretical foundation for clinical prevention and treatment of this condition, ultimately enhancing patient prognosis.

Obeticholic acid ameliorates sepsis-induced renal mitochondrial damage by inhibiting the NF-κb signaling pathway

Acute kidney injury (AKI), a common complication of sepsis, might be caused by overactivated inflammation, mitochondrial damage, and oxidative stress. However, the mechanisms underlying sepsis-induced AKI (SAKI) have not been fully elucidated, and there is a lack of effective therapies for AKI. To this end, this study aimed to investigate whether obeticholic acid (OCA) has a renoprotective effect on SAKI and to explore its mechanism of action. Through bioinformatics analysis, our study confirmed that the mitochondria might be a critical target for the treatment of SAKI. Thus, a septic rat model was established by cecal ligation puncture (CLP) surgery. Our results showed an evoked inflammatory response via the NF-κB signaling pathway and NLRP3 inflammasome activation in septic rats, which led to mitochondrial damage and oxidative stress. OCA, an Farnesoid X Receptor (FXR) agonist, has shown anti-inflammatory effects in numerous studies. However, the effects of OCA on SAKI remain unclear. In this study, we revealed that pretreatment with OCA can inhibit the inflammatory response by reducing the synthesis of proinflammatory factors (such as IL-1β and NLRP3) via blocking NF-κB and alleviating mitochondrial damage and oxidative stress in the septic rat model. Overall, this study provides insight into the excessive inflammation-induced SAKI caused by mitochondrial damage and evidence for the potential use of OCA in SAKI treatment.

Mitophagy mediated by HIF-1α/FUNDC1 signaling in tubular cells protects against renal ischemia/reperfusion injury

Acute kidney injury (AKI) is associated with a high mortality rate. Pathologically, renal ischemia/reperfusion injury (RIRI) is one of the primary causes of AKI, and hypoxia-inducible factor (HIF)-1α may play a defensive role in RIRI. This study assessed the role of hypoxia-inducible factor 1α (HIF-1α)-mediated mitophagy in protection against RIRI in vitro and in vivo. The human tubular cell line HK-2 was used to assess hypoxia/reoxygenation (H/R)-induced mitophagy through different in vitro assays, including western blotting, immunofluorescence staining, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL), and reactive oxygen species (ROS) measurement. Additionally, a rat RIRI model was established for evaluation by renal histopathology, renal Doppler ultrasound, and transmission electron microscopy to confirm the in vitro data. The selective HIF-1α inhibitor LW6 reduced H/R-induced mitophagy but increased H/R-induced apoptosis and ROS production. Moreover, H/R treatment enhanced expression of the FUN14 domain-containing 1 (FUNDC1) protein. Additionally, FUNDC1 overexpression reversed the effects of LW6 on the altered expression of light chain 3 (LC3) BII and voltage-dependent anion channels as well as blocked the effects of HIF-1α inhibition in cells. Pretreatment of the rat RIRI model with roxadustat, a novel oral HIF-1α inhibitor, led to decreased renal injury and apoptosis in vivo. In conclusion, the HIF-1α/FUNDC1 signaling pathway mediates H/R-promoted renal tubular cell mitophagy, whereas inhibition of this signaling pathway protects cells from mitophagy, thus aggravating apoptosis, and ROS production. Accordingly, roxadustat may protect against RIRI-related AKI.

MRG15 promotes cell apoptosis through inhibition of mitophagy in hyperlipidemic acute pancreatitis

Hyperlipidemia is a common cause of acute pancreatitis (AP), often leading to more severe clinical symptoms. The mortality factor 4-like protein 1 (MORF4L1, also called MRG15) plays a crucial role in regulating lipid metabolism. Therefore, this study aimed to explore the mechanism of MRG15 in hyperlipidemic acute pancreatitis (HAP). Mendelian randomization, transcriptome analysis, and single-cell analysis were employed to explore the association between MRG15 and AP by utilizing publicly available databases. In vivo, hypertriglyceridemia mouse models were created by intraperitoneal injection of P407 or using APOE-deficient mice. Subsequently, the HAP model was induced by cerulean. In vitro, a cell model of HAP was established by initially exposing cells to palmitic acid to simulate a high-fat environment, followed by cerulein treatment. Subsequently, MRG15-related indicators were measured. Through Mendelian randomization, it was discovered that there is a positive correlation between genetic expression of MRG15 and the risk of AP. Transcriptome and single-cell analysis revealed that elevated MRG15 expression in AP contributes to lipid metabolism disorders and the activation of apoptosis pathways in pancreatic acinar cells. MRG15 is found to be significantly upregulated in cases of HAP. Knocking down MRG15 led to an increase in mitophagy and a decrease in apoptosis in pancreatic cells, and this effect was reversed when the mitochondrial Tu translation elongation factor (TUFM) was simultaneously knocked down. MRG15 inhibits mitophagy by degrading TUFM, ultimately promoting cell apoptosis and worsening the progression of HAP.

Mitochondrial dysfunction and NLRP3 inflammasome: key players in kidney stone formation

The mitochondrion serves as a critical intracellular organelle, engaging in essential roles in the regulation of energy production, oxidative stress management, calcium homeostasis, and apoptosis. One such disease that has been particularly associated with these functions is kidney stone disease (KSD), specifically calcium oxalate (CaOx). It is underpinned by oxidative stress and tissue inflammation. Recent studies have shed light on the vital involvement of mitochondrial dysfunction, the nucleotide-binding domain and leucine-rich repeat containing protein 3 (NLRP3) inflammasome, endoplasmic reticulum stress and subsequent cell death in CaOx crystal retention and aggregation. These processes are pivotal in the pathogenesis of kidney stone formation. This review focuses on the pivotal roles of mitochondria in renal cell functions and provides an overview of the intricate interconnectedness between mitochondrial dysfunction and NLRP3 inflammasome activation in the context of KSD. It is essential to recognise the utmost significance of gaining a comprehensive understanding of the mechanisms that safeguard mitochondrial function and regulate the NLRP3 inflammasome. Such knowledge carries significant scientific implications and opens up promising avenues for the development of innovative strategies to prevent the formation of kidney stones.

GPR40 agonist ameliorates neurodegeneration and motor impairment by regulating NLRP3 inflammasome in Parkinson's disease animal models

Parkinson's disease (PD) is characterized by the progressive degeneration of dopaminergic neurons in the substantia nigra (SN) and accumulation of intracellular α-synuclein (ɑ-syn) aggregates known as Lewy bodies and Lewy neurites. Levels of polyunsaturated fatty acids (PUFAs) have previously been shown to be reduced in the SN of PD patients. G protein-coupled receptor 40 (GPR40) serves as a receptor for PUFAs, playing a role in neurodevelopment and neurogenesis. Additionally, GPR40 has been implicated in several neuropathological conditions, such as apoptosis and inflammation, suggesting its potential as a therapeutic target in PD. In this study, we investigated the neuroprotective effects of the GPR40 agonist, TUG469 in PD models. Our results demonstrated that TUG469 reduces the neurotoxicity induced by 6-OHDA in SH-SY5Y cells. In 6-OHDA-induced PD model mice, TUG469 treatment improved motor impairment, preserved dopaminergic fibers and cell bodies in the striatum (ST) or SN, and attenuated 6-OHDA-induced microgliosis and astrogliosis in the brain. Furthermore, in a PD model involving the injection of mouse ɑ-syn fibrils into the brain (mPFFs-PD model), TUG469 treatment reduced the levels of pSer129 ɑ-syn, and decreased microgliosis and astrogliosis. Our investigation also revealed that TUG469 modulates inflammasome activation, apoptosis, and autophagy in the 6-OHDA-PD model, as evidenced by the results of RNA-seq and western blotting analyses. In summary, our findings highlight the neuroprotective effects of GPR40 agonists on dopaminergic neurons and their potential as therapeutic agents for PD. These results underscore the importance of targeting GPR40 in PD treatment, particularly in mitigating neuroinflammation and preserving neuronal integrity.

YAP1 exacerbates pyroptosis and senescence in nucleus pulposus cells by promoting BNIP3-mediated mitophagy

Yes-associated protein 1 (YAP1) is a crucial downstream effector of the Hippo pathway that plays a role in regulating inflammation and mitochondrial function. However, whether YAP1 regulates pyroptosis in nucleus pulposus (NP) cells caused by inflammation via mitophagy remains unclear. This study aimed to investigate the effects of YAP1 on the pyroptosis of NP cells induced by LPS. Here, we demonstrated that the protein expression of YAP1 in the NP tissue of degenerative discs was significantly reduced. Next, we found that NLRP3 inflammasome activation in YAP1-overexpressing (YAP1-ov) NP cells was further enhanced in the LPS-induced inflammatory microenvironment. YAP1-ov strongly aggravated inflammation-induced pyroptosis and senescence, but these effects were reversed by the inhibition of BNIP3-mediated mitophagy. However, comparative analysis of the overexpression of YAP1 in normal discs and discs after annulus fibrosus puncture revealed that YAP1-ov accelerated the degeneration of normal discs and attenuated the degeneration of annulus fibrosus punctured discs in vivo. Additionally, YAP1-ov upregulated the expression of TNFAIP3, an anti-inflammatory protective protein, and CLPP, a vital protein in the mitochondrial unfolded protein response, in NP cells. Collectively, the above results revealed that YAP1 exacerbates LPS-induced pyroptosis and senescence of NP cells by promoting BNIP3-mediated mitophagy, which causes disc degeneration. Notably, YAP1-ov mitigated the degeneration of the disc caused by annular needle puncture in vivo, suggesting its potential as a therapeutic candidate foracute IDD injury.

Copper aggravated synaptic damage after traumatic brain injury by downregulating BNIP3-mediated mitophagy

Synaptic damage is a crucial pathological process in traumatic brain injury. However, the mechanisms driving this process remain poorly understood. In this report, we demonstrate that the accumulation of damaged mitochondria, resulting from impaired mitphagy, plays a significant role in causing synaptic damage. Moreover, copper induced downregulation of BNIP3 is a key player in regulating mitophagy. DMSA alleviates synaptic damage and mitochondrial dysfunction by promoting urinary excretion of copper. Mechanistically, we find that copper downregulate BNIP3 by increasing the nuclear translocation of NFKB, which is triggered by TRIM25-mediated ubiquitination-dependent degradation of NFKBIA. Our study underscores the importance of copper accumulation in the regulation of BNIP3-mediated mitophagy and suggests that therapeutic targeting of the copper-TRIM25-NFKB-BNIP3 axis holds promise to attenuate synaptic damage after traumatic brain injury.

Myocardial ischemia-reperfusion injury: The balance mechanism between mitophagy and NLRP3 inflammasome

Myocardial ischemia-reperfusion injury (MIRI) is an injury to cardiomyocytes due to restoration of blood flow after myocardial infarction (MI). It has recently gained much attention in clinical research with special emphasis on the roles of mitochondrial autophagy and inflammation. A mild inflammatory response promotes recovery of post-ischemic cardiomyocyte function and vascular regeneration, but a severe inflammatory response can cause irreversible and substantial cellular damage. Similarly, moderate mitochondrial autophagy can help inhibit excessive inflammation and protect cardiomyocytes. However, MIRI is aggravated when mitochondrial function is disrupted, such as inadequate clearance of damaged mitochondria or excessive activation of mitophagy. How to moderately control mitochondrial autophagy while promoting its balance with nucleotide-binding oligomerization structural domain receptor protein 3 (NLRP3) inflammasome activation is critical. In this paper, we reviewed the molecular mechanisms of mitochondrial autophagy and NLRP3 inflammasome, described the interaction between NLRP3 inflammasome and mitochondrial autophagy, and the effects of different signaling pathways and molecular proteins on MIRI, to provide a reference for future research.

Nanotechnology-Based Drug Delivery Systems for Treating Acute Kidney Injury

Acute kidney injury (AKI) is a disease that is characterized by a rapid decline in renal function and has a relatively high incidence in hospitalized patients. Sepsis, renal hypoperfusion, and nephrotoxic drug exposure are the main causes of AKI. The major therapy measures currently include supportive treatment, symptomatic treatment, and kidney transplantation. These methods are supportive treatments, and their results are not satisfactory. Fortunately, many new treatments that markedly improve the AKI therapy efficiency are emerging. These include antioxidant therapy, ferroptosis therapy, anti-inflammatory therapy, autophagy therapy, and antiapoptotic therapy. In addition, the development of nanotechnology has further promoted therapeutic effects on AKI. In this review, we highlight recent advances in the development of nanocarriers for AKI drug delivery. Emphasis has been placed on the latest developments in nanocarrier modification and design. We also summarize the applications of different nanocarriers in AKI treatment. Finally, the advantages and challenges of nanocarrier applications in AKI are summarized, and several nanomedicines that have been approved for clinical trials to treat diverse kidney diseases are listed.

Mitophagy in Cell Death Regulation: Insights into Mechanisms and Disease Implications

Mitophagy, a selective form of autophagy, plays a crucial role in maintaining optimal mitochondrial populations, normal function, and intracellular homeostasis by monitoring and removing damaged or excess mitochondria. Furthermore, mitophagy promotes mitochondrial degradation via the lysosomal pathway, and not only eliminates damaged mitochondria but also regulates programmed cell death-associated genes, thus preventing cell death. The interaction between mitophagy and various forms of cell death has recently gained increasing attention in relation to the pathogenesis of clinical diseases, such as cancers and osteoarthritis, neurodegenerative, cardiovascular, and renal diseases. However, despite the abundant literature on this subject, there is a lack of understanding regarding the interaction between mitophagy and cell death. In this review, we discuss the main pathways of mitophagy, those related to cell death mechanisms (including apoptosis, ferroptosis, and pyroptosis), and the relationship between mitophagy and cell death uncovered in recent years. Our study offers potential directions for therapeutic intervention and disease diagnosis, and contributes to understanding the molecular mechanism of mitophagy.

LATS1 inhibitor and zinc supplement synergistically ameliorates contrast-induced acute kidney injury: Induction of Metallothionein-1 and suppression of tubular ferroptosis

Contrast-induced acute kidney injury (CI-AKI) is a prevalent cause of renal dysfunction among hospitalized patients, yet the precise pathogenesis and effective therapeutic strategies remain elusive. In this study, we investigated the role of tubular ferroptosis in both experimental CI-AKI models and in primary tubular epithelial cells (PTECs) treated with ioversol. Using whole exome sequencing, we identified metallothioneins (MTs) as being among the most significantly downregulated genes following ioversol exposure. Our findings reveal that overexpression of Mt1 mitigates, whereas suppression of Mt-1 exacerbates, ioversol-induced tubular ferroptosis. Interestingly, the level of MTF1 (metal regulatory transcription factor 1), a principal regulator of Mt1, was found to increase in response to ioversol treatment. We further elucidated that ioversol activates LATS1 (Large tumor suppressor homolog 1), a kinase that promotes the phosphorylation and nuclear translocation of MTF1, thereby inhibiting its transcriptional activity for Mt1. Both genetic and pharmacological inhibition of LATS1 reversed the ioversol-induced suppression of Mt-1. From a therapeutic perspective, the LATS1 inhibitor TDI-011536, in combination with zinc acetate, was administered to a rodent model of CI-AKI. Our data indicate that this combination synergistically upregulates Mt1 expression and provides protection against contrast media-induced tubular ferroptosis. In summary, our study demonstrates that the reduction of Mt-1 contributes to tubular ferroptosis associated with CI-AKI. We show that contrast media activate LATS1, which in turn suppresses the transcriptional activity of MTF1 for Mt1. Herein, the combination of zinc acetate and a LATS1 inhibitor emerges as a potential therapeutic approach for the treatment of CI-AKI.

Codelivery of Dual Gases with Metal-Organic Supramolecular Cage-Based Microenvironment-Responsive Nanomedicine for Atherosclerosis Therapy

Atherosclerosis (AS) is a common cause of coronary heart disease and stroke. The delivery of exogenous H2S and in situ production of O2 within atherosclerotic plaques can help suppress inflammatory cell infiltration and alleviate disease progression. However, the uncontrolled release of gas donors hinders achieving effective drug concentrations and causes toxic effects. Herein, diallyl trisulfide (DATS)-loaded metal-organic cage (MOC)-68-doped MnO2 nanoparticles are developed as a microenvironment-responsive nanodrug with the capacity for the in situ co-delivery of H2S and O2 to inflammatory cells within plaques. This nanomedicine exhibited excellent monodispersity and stability and protected DATS from degradation in the circulation. In vitro studies showed that the nanomedicine reduced macrophage polarization toward an inflammatory phenotype and inhibited the formation of foam cells, while suppressing the expression of NOD-like receptor thermal protein domain associated protein 3 (NLRP3) and interleukin-1β. In a mouse model of ApoE-/- genotype, the nanomedicine reduces the plaque burden, inflammatory infiltration, and hypoxic conditions within the plaques. Furthermore, the treatment process and therapeutic effects can be monitored by magnetic resonance image (MRI), in real time upon Mn2+ release from the acidic- and H2O2- microenvironment-responsive MnO2 nanoparticles. The DATS-loaded MOC-68-doped MnO2-based nanodrug holds great promise as a novel theranostic platform for AS.

Honeycomb Bionic Graphene Oxide Quantum Dot/Layered Double Hydroxide Composite Nanocoating Promotes Osteoporotic Bone Regeneration via Activating Mitophagy

Abnormal osteogenic and remodeling microenvironment due to osteoblast apoptosis are the primary causes of delayed fracture healing in osteoporotic patients. Magnesium (Mg) alloys exhibit biodegradability and appropriate elastic moduli for bone defects in osteoporosis, but the effect on the local bone remodeling disorder is still insufficient. Inspired by the "honeycomb," layered double hydroxide (LDH) with regular traps with graphene oxide quantum dots (GOQDs) inlayed is constructed by pulsed electrodeposition to generate GOQD/LDH composite nanocoatings on the surfaces of Mg alloy substrates. The honeycomb bionic multi-layer stereoscopic structure shows good regulation of the degradation of Mg alloy for the support of healing time required for osteoporotic bone defect. Within its lattice, the local microenvironment conducive to osteogenesis is provided by both the rescue effect of GOQD and LDH. The osteoblast apoptosis is rescued due to the activation of mitophagy to clear dysfunctional mitochondria, where the upregulation of BNIP3 phosphorylation played a key role. The osteoporotic rat model of femoral defects confirmed the improvement of bone regeneration and osseointegration of GOQD/LDH coating. In summary, honeycomb bionic composite nanocoatings with controllable degradation and excellent pro-osteogenic performance demonstrated a promising design strategy on Mg alloy implants in the therapy of osteoporotic bone defects.

Remifentanil-induced inflammation in microglial cells: Activation of the PAK4-mediated NF-κB/NLRP3 pathway and onset of hyperalgesia

BACKGROUND

The perioperative use of remifentanil is associated with postoperative hyperalgesia, which can impair recovery and extend hospitalization. Recent studies have revealed that microglia-mediated activation of the NLRP3 inflammasome plays a critical role in opioid-induced hyperalgesia, with NF-κB acting as a pivotal activation point for NLRP3. Despite these findings, the specific molecular mechanisms underlying remifentanil-induced postoperative hyperalgesia remain unclear. This study aims to develop a model of remifentanil-induced hyperalgesia and investigate the molecular mechanisms, focusing on the NF-κB/NLRP3 pathway, using both in vitro and in vivo approaches.

METHOD

We established a remifentanil-induced hyperalgesia model and performed proteomic analysis to identify differential protein expression in the spinal cord tissue of rats. NLRP3 or PAK4 antagonists were administered intrathecally in vivo, and mechanical pain thresholds in the hind paws were measured using Von Frey testing. In vitro, we applied NLRP3 or PAK4 inhibitors or used lentivirus infection to silence PAK4, NF-κB, and NLRP3 genes. Protein expression was assessed through immunohistochemistry, immunofluorescence, and Western blotting. Additionally, ELISA was performed to measure IL-1β and IL-18 levels, and RT-qPCR was conducted to evaluate the transcription of target genes.

RESULTS

Proteomic analysis revealed that remifentanil upregulates PAK4 protein in spinal cord tissue two hours after the surgery. In addition, remifentanil induces morphological changes in the spinal cord dorsal horn, characterized by increased expression of PAK4, p-p65, NLRP3 and Iba-1 proteins, which in turn leads to elevated IL-1β and IL-18 levels and an inflammatory response. Intrathecal injection of NLRP3 or PAK4 inhibitors mitigates remifentanil-induced hyperalgesia and associated changes. In vitro, downregulation of PAK4 inhibits the increase in PAK4, p-p65, NLRP3 and Caspase-1 induced by LPS. Conversely, the downregulation of NLRP3 does not impact the levels of PAK4 and p-p65 proteins, aligning with the in vivo results and suggesting that PAK4 acts as an upstream signaling molecule of NLRP3.

CONCLUSION

Remifentanil can increase PAK4 expression in spinal cord dorsal horn cells by activating the NF-κB/NLRP3 pathway and mediating microglial activation, thereby contributing to postoperative hyperalgesia.

The role of mitochondrial autophagy in osteoarthritis

Osteoarthritis (OA) is a progressive degenerative joint disease, and the underlying molecular mechanisms of OA remain poorly understood. This study aimed to elucidate the relationship between mitochondrial autophagy and OA by identifying key regulatory genes and their biological functions. Utilizing bioinformatics analyses of RNA expression profiles from the GSE55235 dataset, we identified 2,136 differentially expressed genes, leading to the discovery of hub genes associated with mitochondrial autophagy and OA. Gene set enrichment analysis (GSEA) revealed their involvement in critical pathways, highlighting their potential roles in OA pathogenesis. Furthermore, our study explored the immunological landscape of OA, identifying distinct immune cell infiltration patterns that contribute to the disease's inflammatory profile. We also evaluated the therapeutic potential of drugs targeting these hub genes, suggesting potential approaches for OA treatment. Collectively, this study advances our knowledge of mitochondrial autophagy in OA and proposes promising biomarkers and therapeutic targets.

Predicting the potential mechanism of radix chimonanthi pracecocis in treating osteoarthritis by network pharmacology analysis combined with experimental validation

ETHNOPHARMACOLOGICAL RELEVANCE

Radix Chimonanthi Pracecocis (RCP), also known as Tiekuaizi, widely used by the Miao community in Guizhou, exhibits diverse biological activities and holds promise for the treatment of osteoarthritis (OA). However, there is a lack of contemporary pharmacological research in this area.

AIMS OF THE STUDY

This study aims to explore the potential of targets and mechanisms of RCP in the treatment of OA.

MATERIALS AND METHODS

The chemical components of RCP were identified using UPLC-MS/MS, and active components were determined based on the Lipinski rule. RCP and OA-related targets were retrieved from public databases such as TCMSP and GeneCards. Network pharmacology approaches were employed to identify key genes. The limma package (version 3.40.2) in R 4.3.2 was used to screen for differentially expressed genes (DEGs) between OA and healthy individuals in GSE82107. DEGs were analyzed using an independent sample t-test and receiver operating characteristic analysis in GraphPad Prism 9.5.1. Additionally, molecular docking (SYBYL2.1.1) was used to analyze the binding interactions between the active components and target proteins. Finally, we established a papain-induced osteoarthritis (OA) rat model and treated it with RCP aqueous extract by gavage. We validated relevant indicators using real-time fluorescence quantitative polymerase chain reaction, Western blot, immunohistochemistry, and enzyme-linked immunosorbent assays.

RESULTS

Seven active components and 53 targets were identified. The results of GO and KEGG enrichment analyses confirmed the significant role of RCP in the regulation of pyroptosis. Hypoxia-inducible factor-1α (HIF-1α) was identified as a key gene involved in the main biological functions. Molecular docking analysis revealed that Praecoxin, Isofraxidin, Esculin, and Naringenin can bind to the nucleotide-binding domain, leucine-rich repeat, and pyrin domain-containing protein 3 (NLRP3) (T-Score >5). Additionally, Praecoxin can bind to HIF-1α (T-Score >5). In vivo experiments demonstrated that RCP significantly affects the NLRP3 inflammasome, which is regulated by the HIF-1α pathway. RCP inhibited pyroptosis and reduced synovial inflammation.

CONCLUSIONS

This study confirmed the efficacy of RCP aqueous extract in the treatment of OA and identified seven active components (esculin, dihydrokaempferol, naringenin, praecoxin, carnosol, hydroxyvalerenic acid, isofraxidin) that may play an anti-pyroptosis role in the treatment of OA by downregulating the expression of HIF-1α and NLRP3 inflammasome.

Micheliolide ameliorates lipopolysaccharide-induced acute kidney injury through suppression of NLRP3 activation by promoting mitophagy via Nrf2/PINK1/Parkin axis

BACKGROUND

Sepsis-associated acute kidney injury (SA-AKI) represents a frequent complication of in critically ill patients. The objective of this study is to illuminate the potential protective activity of Micheliolide (MCL) and its behind mechanism against SA-AKI.

METHODS

The protective potential of MCL on SA-AKI was investigated in lipopolysaccharide (LPS) treated HK2 cells and SA-AKI mice model. The mitochondrial damage was determined by detection of reactive oxygen species and membrane potential. The Nrf2 silencing was achieved by transfection of Nrf2-shRNA in HK2 cells, and Nrf2 inhibitor, ML385 was employed in SA-AKI mice. The mechanism of MCL against SA-AKI was evaluated through detecting hallmarks related to inflammation, mitophagy and Nrf2 pathway via western blotting, immunohistochemistry, and enzyme linked immunosorbent assay.

RESULTS

MCL enhanced viability, suppressed apoptosis, decreased inflammatory cytokine levels and improved mitochondrial damage in LPS-treated HK2 cells, and ameliorated renal injury in SA-AKI mice. Moreover, MCL could reduce the activation of NLRP3 inflammasome via enhancing mitophagy. Additionally, Nrf2 deficiency reduced the suppression effect of MCL on NLRP3 inflammasome activation and blocked the facilitation effect of MCL on mitophagy in LPS-treated HK2 cells, the consistent is true for ML385 treatment in SA-AKI mice.

CONCLUSIONS

MCL might target Nrf2 and further reduce the NLRP3 inflammasome activation via enhancing mitophagy, which alleviated SA-AKI.

Ginseng polysaccharide promotes the apoptosis of colon cancer cells via activating the NLRP3 inflammasome

BACKGROUND

Ginseng polysaccharide (GPS) is an ingredient of ginseng with documented anti-tumor properties. However, its effect on colon cancer and the underlying molecular mechanisms have not been investigated clearly.

METHODS

Cell viability of HT29 and CT26 cells treated with different concentrations of GPS was assessed using the Cell Counting Kit-8 (CCK-8) assay. Western blot assay was used to detect the expression of apoptotic proteins, while the mRNA levels were assessed by real-time quantitative polymerase chain reaction (RT-qPCR). Transwell migration assays were used to examine the migration and invasion of cells.

RESULTS

The results revealed that GPS effectively suppressed the proliferation of HT29 and CT26 cells. We demonstrated an upregulation of apoptotic proteins in GPS-treated cells, including Bax, cleaved Caspase-3, and p-p53. GPS treatment also increased the mRNA levels of cytochrome C and Bax. Furthermore, the results showed that GPS treatment concurrently promoted the activation of nucleotide-binding domain leucine-rich family pyrin-containing 3 (NLRP3) inflammasome. Transwell migration assays showed that GPS inhibited the migratory and invasive abilities of colon cancer cells. As expected, inhibition of NLRP3 expression using INF39 attenuated the inhibitory effect of GPS on migration and invasion. Upon NLRP3 inhibition, GPS-induced apoptosis was dramatically alleviated, accompanied by a reduction in the expression of apoptotic proteins.

CONCLUSION

In conclusion, this research provides compelling evidence that the GPS-induced NLRP3 signaling pathway plays a pivotal role in apoptosis of colon cells, suggesting potential clinical implications for the therapeutic intervention of colon cancer. Thus, GPS might be a promising anti-tumor drug for the treatment of colorectal cancer.

Role of mitophagy in pulmonary hypertension: Targeting the mechanism and pharmacological intervention

Mitophagy, a crucial pathway in eukaryotic cells, selectively eliminates dysfunctional mitochondria, thereby maintaining cellular homeostasis via mitochondrial quality control. Pulmonary hypertension (PH) refers to a pathological condition where pulmonary arterial pressure is abnormally elevated due to various reasons, and the underlying pathogenesis remains elusive. This article examines the molecular mechanisms underlying mitophagy, emphasizing its role in PH and the progress in elucidating related molecular signaling pathways. Additionally, it highlights current drug regulatory pathways, aiming to provide novel insights into the prevention and treatment of pulmonary hypertension.

Inhibition of cGAS attenuates neonatal hypoxic-ischemic encephalopathy via regulating microglia polarization and pyroptosis

Background

Neonatal hypoxic-ischemic encephalopathy (HIE) is a condition causing brain injury in newborns with unclear pathogenesis. Cyclic GMP-AMP synthase (cGAS)/stimulator of interferon genes (STING) signaling pathway and NOD-like receptor protein 3 (NLRP3) mediated pyroptosis are thought to be involved in the pathological process of HIE, but whether these two mechanisms act independently is still unknown. Therefore, we aim to clarify whether there is any interaction between these two pathways and thus synergistically affects the progression of HIE.

Methods

The HIE model of neonatal rats was established using the Rice-Vannucci method. The potential therapeutic effect of RU.521 targeting cGAS on HIE was explored through rescue experiment. Twenty-four hours after modeling was selected as observation point, sham + vehicle group, HIE + vehicle group and HIE + RU.521 group were established. A complete medium of BV2 cells was adjusted to a glucose-free medium, and the oxygen-glucose deprivation model was established after continuous hypoxia for 4 hours and reoxygenation for 12 to 24 hours. 2,3,5-triphenyl tetrazolium chloride staining was employed to detect ischemic cerebral infarction in rat brain tissue, and hematoxylin and eosin staining was used to observe tissue injury. Immunofluorescence was applied to monitor the expression of cGAS. Real-time quantitative polymerase chain reaction and western blot were utilized to detect the expression of messenger RNA and protein.

Results

cGAS expression was increased in brain tissues of neonatal rats with HIE, and mainly localized in microglia. RU.521 administration reduced infarct size and pathological damage in rat HIE. Moreover, blocking cGAS with RU.521 significantly reduced inflammatory conditions in the brain by down-regulating STING expression, decreasing NLRP3 inflammasome activation and reducing microglial pyroptosis both in vivo and in vitro. Besides, RU.521 promoted the switching of BV2 cells towards the M2 phenotype.

Conclusions

This study revealed a link between the cGAS/STING pathway and the NLRP3/GSDMD/pyroptosis pathway in neonatal HIE. Furthermore, the small molecule compound RU.521 can negatively regulate cGAS/STING/NLRP3/pyroptosis axis and promote M2 polarization in microglia, which provides a potential therapeutic strategy for the treatment of neuroinflammation in HIE.

FBXW7-Mediated Downregulation of GPX4 Aggravates Acute Kidney Injury Following Ischemia‒Reperfusion

Acute kidney injury (AKI) is a prevalent and potentially life-threatening complication characterized by a high incidence and mortality. A large number of studies have emphasized the role of ferroptosis in AKI. Moreover, FBXW7, a ubiquitin ligase, has been implicated in acute organ injury. Analysis of the GEO database (GSE98622) revealed increased FBXW7 mRNA levels in the kidney following ischemia‒reperfusion (IR). However, the role of FBXW7 in AKI has not been elucidated. Therefore, this study aimed to investigate the role of FBXW7 in IR-AKI and its underlying mechanisms. Here, we found that IR could induce AKI and increase FBXW7 expression, while the ferroptosis inhibitor Fer-1 alleviated AKI and decreased FBXW7 expression. Furthermore, we treated HK-2 cells with hypoxia for 12 h and reoxygenation for 4 h (H12R4) to simulate IR-AKI and investigated the impact of modulating FBXW7 expression on ferroptosis by employing ferroptosis-related agonists or inhibitors. Our findings revealed that H12R4 induced HK2 ferroptosis and increased the expression of FBXW7. FBXW7 overexpression in control cells exacerbated erastin-induced ferroptosis, and FBXW7 knockdown inhibited ferroptosis in H12R4-treated cells. Mechanistically, we confirmed that FBXW7 can bind to GPX4, a key molecule that inhibits ferroptosis. The half-life of the GPX4 protein decreased after FBXW7 overexpression, GPX4 ubiquitination increased after H12R4, and GPX4 degradation decreased after FBXW7 knockdown. In conclusion, our results indicated that FBXW7 plays an important role in the development of IR-AKI by promoting ferroptosis through the downregulation of GPX4 expression. This study provides new insight into FBXW7 as a potential target for treating AKI.

Lipophagy and Mitophagy in Renal Pathophysiology

BACKGROUND

The lysosomal autophagic pathway plays a fundamental role in cellular and tissue homeostasis, and its deregulation is linked to human pathologies including kidney diseases. Autophagy can randomly degrade cytoplasmic components in a nonselective manner commonly referred to as bulk autophagy. In contrast, selective forms of autophagy specifically target cytoplasmic structures such as organelles and protein aggregates, thereby being important for cellular quality control and organelle homeostasis.

SUMMARY

Research during the past decades has begun to elucidate the role of selective autophagy in kidney physiology and kidney diseases.

KEY MESSAGES

In this review, we will summarize the knowledge on lipophagy and mitophagy, two forms of selective autophagy important in renal epithelium homeostasis, and discuss how their deregulations contribute to renal disease progression.

Breaking the vicious cycle: Targeting the NLRP3 inflammasome for treating sepsis-associated encephalopathy

Sepsis-associated encephalopathy (SAE) is a collection of clinical syndromes resulting from sepsis and characterized by widespread brain dysfunction. The high prevalence of SAE has adverse outcomes on the clinical management and prognosis of sepsis patients. However, currently, there are no effective treatments to ameliorate SAE. The pathogenesis of SAE is complex, including neuroinflammation and microglia activation, destruction of the blood-brain barrier (BBB), neurotransmitter dysfunction, cerebral metabolism and mitochondrial impairment, accumulation of amyloid beta and tauopathy, complement activation, among others. Furthermore, these mechanisms intertwine with each other, further complicating the comprehension of SAE. Among them, neuroinflammation mediated by hyperactivated microglia is considered the primary etiology of SAE. This instigates a detrimental cycle wherein BBB permeability escalates, facilitating direct damage to the central nervous system (CNS) by various neurotoxic substances. Activation of the NLRP3 inflammasome, situated within microglia, can be triggered by diverse danger signals, leading to cell pyroptosis, apoptosis, and tauopathy. These complex processes intricately regulate the onset and progression of neuroinflammation. In this review, we focus on elucidating the inhibitory regulatory mechanism of the NLRP3 inflammasome in microglia, which ultimately manifests as suppression of the inflammatory response. Our ultimate objective is to augment comprehension regarding the role of microglial NLRP3 inflammasome as we explore potential targets for therapeutic interventions against SAE.

DDIT3 aggravates TMJOA cartilage degradation via Nrf2/HO-1/NLRP3-mediated autophagy

OBJECTIVE

DNA damage-inducible transcript 3 (DDIT3), as a downstream transcription factor of endoplasmic reticulum stress, is reported to regulate chondrogenic differentiation under physiological and pathological state. However, the specific involvement of DDIT3 in the degradation of condylar cartilage of temporomandibular joint osteoarthritis (TMJOA) is unclarified.

DESIGN

The expression patterns of DDIT3 in condylar cartilage from monosodium iodoacetate-induced TMJOA mice were examined to uncover the potential role of DDIT3 in TMJOA. The Ddit3 knockout (Ddit3-/-) mice and their wildtype littermates (Ddit3+/+) were used to clarify the effect of DDIT3 on cartilage degradation. Primary condylar chondrocytes and ATDC5 cells were applied to explore the mechanisms of DDIT3 on autophagy and extracellular matrix (ECM) degradation in chondrocytes. The autophagy inhibitor chloroquine (CQ) was used to determine the effect of DDIT3-inhibited autophagy in vivo.

RESULTS

DDIT3 were highly expressed in condylar cartilage from TMJOA mice. Ddit3 knockout alleviated condylar cartilage degradation and subchondral bone loss, compared with their wildtype littermates. In vitro study demonstrated that DDIT3 exacerbated ECM degradation in chondrocytes induced by TNF-α through inhibiting autophagy. The intraperitoneal injection of CQ further confirmed that Ddit3 knockout alleviated cartilage degradation in TMJOA through activating autophagy in vivo.

CONCLUSIONS

Our findings identified the crucial role of DDIT3-inhibited autophagy in condylar cartilage degradation during the development of TMJOA.

FAM3A plays a key role in protecting against tubular cell pyroptosis and acute kidney injury

Acute kidney injury (AKI) is in high prevalence worldwide but with no therapeutic strategies. Programmed cell death in tubular epithelial cells has been reported to accelerate a variety of AKI, but the major pathways and underlying mechanisms are not defined. Herein, we identified that pyroptosis was responsible for AKI progression and related to ATP depletion in renal tubular cells. We found that FAM3A, a mitochondrial protein that assists ATP synthesis, was decreased and negatively correlated with tubular cell injury and pyroptosis in both mice and patients with AKI. Knockout of FAM3A worsened kidney function decline, increased macrophage and neutrophil cell infiltration, and facilitated tubular cell pyroptosis in ischemia/reperfusion injury model. Conversely, FAM3A overexpression alleviated tubular cell pyroptosis, and inhibited kidney injury in ischemic AKI. Mechanistically, FAM3A promoted PI3K/AKT/NRF2 signaling, thus blocking mitochondrial reactive oxygen species (mt-ROS) accumulation. NLRP3 inflammasome sensed the overload of mt-ROS and then activated Caspase-1, which cleaved GSDMD, pro-IL-1β, and pro-IL-18 into their mature forms to mediate pyroptosis. Of interest, NRF2 activator alleviated the pro-pyroptotic effects of FAM3A depletion, whereas the deletion of NRF2 blocked the anti-pyroptotic function of FAM3A. Thus, our study provides new mechanisms for AKI progression and demonstrates that FAM3A is a potential therapeutic target for treating AKI.

Renal tubular epithelial cell quality control mechanisms as therapeutic targets in renal fibrosis

Renal fibrosis is a devastating consequence of progressive chronic kidney disease, representing a major public health challenge worldwide. The underlying mechanisms in the pathogenesis of renal fibrosis remain unclear, and effective treatments are still lacking. Renal tubular epithelial cells (RTECs) maintain kidney function, and their dysfunction has emerged as a critical contributor to renal fibrosis. Cellular quality control comprises several components, including telomere homeostasis, ubiquitin-proteasome system (UPS), autophagy, mitochondrial homeostasis (mitophagy and mitochondrial metabolism), endoplasmic reticulum (ER, unfolded protein response), and lysosomes. Failures in the cellular quality control of RTECs, including DNA, protein, and organelle damage, exert profibrotic functions by leading to senescence, defective autophagy, ER stress, mitochondrial and lysosomal dysfunction, apoptosis, fibroblast activation, and immune cell recruitment. In this review, we summarize recent advances in understanding the role of quality control components and intercellular crosstalk networks in RTECs, within the context of renal fibrosis.

Layer-by-Layer Assembly of Renal-Targeted Polymeric Nanoparticles for Robust Arginase-2 Knockdown and Contrast-Induced Acute Kidney Injury Prevention

The mitochondrial enzyme arginase-2 (Arg-2) is implicated in the pathophysiology of contrast-induced acute kidney injury (CI-AKI). Therefore, Arg-2 represents a candid target for CI-AKI prevention. Here, layer-by-layer (LbL) assembled renal-targeting polymeric nanoparticles are developed to efficiently deliver small interfering RNA (siRNA), knockdown Arg-2 expression in renal tubules, and prevention of CI-AKI is evaluated. First, near-infrared dye-loaded poly(lactic-co-glycolic acid) (PLGA) anionic cores are electrostatically coated with cationic chitosan (CS) to facilitate the adsorption and stabilization of Arg-2 siRNA. Next, nanoparticles are coated with anionic hyaluronan (HA) to provide protection against siRNA leakage and shielding against early clearance. Sequential electrostatic layering of CS and HA improves loading capacity of Arg-2 siRNA and yields LbL-assembled nanoparticles. Renal targeting and accumulation is enhanced by modifying the outermost layer of HA with a kidney targeting peptide (HA-KTP). The resultant kidney-targeting and siRNA loaded nanoparticles (PLGA/CS/HA-KTP siRNA) exhibit proprietary accumulation in kidneys and proximal tubular cells at 24 h post-tail vein injection. In iohexol-induced in vitro and in vivo CI-AKI models, PLGA/CS/HA-KTP siRNA delivery alleviates oxidative and nitrification stress, and rescues mitochondrial dysfunction while reducing apoptosis, thereby demonstrating a robust and satisfactory therapeutic effect. Thus, PLGA/CS/HA-KTP siRNA nanoparticles offer a promising candidate therapy to protect against CI-AKI.

LncRNA HILPDA promotes contrast-induced acute kidney injury by recruiting eIF4B to upregulate XPO1 expression

Background

Contrast-induced acute kidney injury (CI-AKI) is a serious and common complication following the use of iodinated contrast media, with a 20% fatality rate. The function of long non-coding RNA HILPDA (lnc-HILPDA) in CI-AKI development was investigated in this study.

Methods

CI-AKI models were constructed by iopromide treatment. Kidney pathological changes were analyzed by HE staining. TUNEL labeling and flow cytometry were used to examine cell apoptosis. CCK-8 assay was used to determine cell viability. The interactions between lnc-HILPDA, eIF4B, and XPO1 were verified by RIP or Co-IP assay.

Results

Lnc-HILPDA was upregulated in CI-AKI, and its knockdown decreased contrast-trigged oxidative stress and apoptosis in HK-2 cells. Mechanically, lnc-HILPDA activated the NF-κB pathway by upregulating XPO1 through interacting with eIF4B. Moreover, the inhibitory effect of lnc-HILPDA downregulation on contrast-induced oxidative stress and apoptosis in HK-2 cells was weakened by XPO1 overexpression.

Conclusion

Lnc-HILPDA accelerated CI-AKI progression by elevating XPO1 expression through eIF4B to activate NF-κB pathway.

NLRP3 Inflammasome Deficiency Alleviates Inflammation and Oxidative Stress by Promoting PINK1/Parkin-Mediated Mitophagy in Allergic Rhinitis Mice and Nasal Epithelial Cells

Purpose

Accumulating evidence indicates that oxidative stress and inflammation are the pathological basis of allergic diseases. Inhibition of NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome could ameliorate allergic rhinitis (AR). Here, we explored the effects and mechanisms that underlie NLRP3 inhibition on oxidative stress and inflammation in AR.

Methods

Ovalbumin (OVA)-induced AR murine model was established using wild-type (WT) and NLRP3-deficient mice. HNEpCs were stimulated with interleukin (IL)-13 with MCC950 pretreatment or PTEN-induced putative kinase 1 (PINK1) siRNA. The indicators of oxidative stress, inflammation, apoptosis, and mitophagy were determined both in vivo and in vitro.

Results

NLRP3 knockout (KO) reduced the frequency of nasal rubbing and sneezing, the infiltration of eosinophils, the number of mast cells, and the accumulation of goblet cells in AR mice after OVA stimulation. The NLRP3 KO AR mice exhibited the increased concentrations of OVA-specific immunoglobulin E (OVA-sIgE), IL-1β, IL-4, IL-13, IL-6, TNF-α, and the upregulated level of IFN-γ. NLRP3 KO significantly inhibited oxidative stress, and also markedly decreased apoptosis in the nasal mucosa of AR mice. Moreover, evaluated protein expressions of PINK1, enzyme 3 (E3) ubiquitin ligase PRKN (Parkin), and LC3 II, decreased expression of TOM20, as well as the increased colocalization of LC3 with mitochondria were observed in NLRP3 KO AR mice. In vitro, IL-13 exposure increased the levels of NLRP3 and IL-1β. Inhibition of NLRP3 using MCC950 enhanced PINK1/Parkin-mediated mitophagy but attenuated inflammation, oxidative stress, and apoptosis. However, PINK1 knockdown abrogated mitophagy and also reversed the protective effects of MCC950 on inflammation, oxidative stress, and apoptosis in HNEpCs stimulated with IL-13.

Conclusion

Inhibition of NLRP3 inflammasome exerts the protective effects on AR by facilitating mitophagy regulated by PINK1/Parkin signaling pathway.

Selenium nanoparticles alleviate renal ischemia/reperfusion injury by inhibiting ferritinophagy via the XBP1/NCOA4 pathway

Acute kidney injury (AKI) is closely related to lysosomal dysfunction and ferroptosis in renal tubular epithelial cells (TECs), for which effective treatments are urgently needed. Although selenium nanoparticles (SeNPs) have emerged as promising candidates for AKI therapy, their underlying mechanisms have not been fully elucidated. Here, we investigated the effect of SeNPs on hypoxia/reoxygenation (H/R)-induced ferroptosis and lysosomal dysfunction in TECs in vitro and evaluated their efficacy in a murine model of ischemia/reperfusion (I/R)-AKI. We observed that H/R-induced ferroptosis was accompanied by lysosomal Fe2+ accumulation and dysfunction in TECs, which was ameliorated by SeNPs administration. Furthermore, SeNPs protected C57BL/6 mice against I/R-induced inflammation and ferroptosis. Mechanistically, we found that lysosomal Fe2+ accumulation and ferroptosis were associated with the excessive activation of NCOA4-mediated ferritinophagy, a process mitigated by SeNPs through the upregulation of X-box binding protein 1 (XBP1). Downregulation of XBP1 promoted ferritinophagy and partially counteracted the protective effects of SeNPs on ferroptosis inhibition in TECs. Overall, our findings revealed a novel role for SeNPs in modulating ferritinophagy, thereby improving lysosomal function and attenuating ferroptosis of TECs in I/R-AKI. These results provide evidence for the potential application of SeNPs as therapeutic agents for the prevention and treatment of AKI.

Kidney Injury in a Murine Hemorrhagic Shock/Resuscitation Model Is Alleviated by sulforaphane's Anti-Inflammatory and Antioxidant Action

Hemorrhagic shock/resuscitation (HS/R) can lead to acute kidney injury, mainly manifested as oxidative stress and inflammatory injury in the renal tubular epithelial cells, as well as abnormal autophagy and apoptosis. Sulforaphane (SFN), an agonist of the nuclear factor-erythroid factor 2-related factor 2 (Nrf2) signaling pathway, is involved in multiple biological activities, such as anti-inflammatory, antioxidant, autophagy, and apoptosis regulation. This study investigated the effect of SFN on acute kidney injury after HS/R in mice. Hemorrhagic shock was induced in mice by controlling the arterial blood pressure at a range of 35-45 mmHg for 90 min within arterial blood withdrawal. Fluid resuscitation was carried out by reintroducing withdrawn blood and 0.9% NaCl. We found that SFN suppressed the elevation of urea nitrogen and serum creatinine levels in the blood induced by HS/R. SFN mitigated pathological alterations including swollen renal tubules and renal casts in kidney tissue of HS/R mice. Inflammation levels and oxidative stress were significantly downregulated in mouse kidney tissue after SFN administration. In addition, the kidney tissue of HS/R mice showed high levels of autophagosomes as observed by electron microscopy. However, SFN can further enhance the formation of autophagosomes in the HS/R + SFN group. SFN also increased autophagy-related proteins Beclin1 expression and suppressed P62 expression, while increasing the ratio of microtubule-associated protein 1 light chain 3 (LC3)-II and LC3-I (LC3-II/LC3-I). SFN also effectively decreased cleaved caspase-3 level and enhanced the ratio of anti-apoptotic protein B cell lymphoma 2 and Bcl2-associated X protein (Bcl2/Bax). Collectively, SFN effectively inhibited inflammation and oxidative stress, enhanced autophagy, thereby reducing HS/R-induced kidney injury and apoptosis levels in mouse kidneys.

Macrophage migration inhibitory factor (MIF) suppresses mitophagy through disturbing the protein interaction of PINK1-Parkin in sepsis-associated acute kidney injury

Damage to renal tubular epithelial cells (RTECs) signaled the onset and progression of sepsis-associated acute kidney injury (SA-AKI). Recent research on mitochondria has revealed that mitophagy plays a crucial physiological role in alleviating injury to RTECs and it is suppressed progressively by the inflammation response in SA-AKI. However, the mechanism by which inflammation influences mitophagy remains poorly understood. We examined how macrophage migration inhibitory factor (MIF), a pro-inflammatory protein, influences the PINK1-Parkin pathway of mitophagy by studying protein-protein interactions when MIF was inhibited or overexpressed. Surprisingly, elevated levels of MIF were found to directly bind to PINK1, disrupting its interaction with Parkin. This interference hindered the recruitment of Parkin to mitochondria and impeded the initiation of mitophagy. Furthermore, this outcome led to significant apoptosis of RTECs, which could, however, be reversed by an MIF inhibitor ISO-1 and/or a new mitophagy activator T0467. These findings highlight the detrimental impact of MIF on renal damage through its disruption of the interaction between PINK1 and Parkin, and the therapeutic potential of ISO-1 and T0467 in mitigating SA-AKI. This study offers a fresh perspective on treating SA-AKI by targeting MIF and mitophagy.

Donepezil promotes skin flap survival through activation of the HIF-1α/VEGF signalling pathway

Flaps are mainly used to repair wounds in the clinical setting but can sometimes experience ischaemic necrosis postoperatively. This study investigated whether donepezil, an acetylcholinesterase inhibitor, can enhance the survival rate of flaps. We randomly allocated 36 rats into control, low-dose (3 mg/kg/day), and high-dose (5 mg/kg/day) groups. On Postoperative day 7, we assessed flap viability and calculated the mean area of viable flap. After euthanizing the rats, we employed immunological and molecular biology techniques to examine the changes in flap tissue vascularization, apoptosis, autophagy, and inflammation. Donepezil enhanced the expression of hypoxia-inducible factor and vascular endothelial growth factor to facilitate angiogenesis. In addition, it elevated the expression of LC3B, p62, and beclin to stimulate autophagy. Furthermore, it increased the expression of Bcl-2 while reducing the expression of Bax, thus inhibiting apoptosis. Finally, it had anti-inflammatory effects by reducing the levels of IL-1β, IL-6, and TNF-α. The results suggest that donepezil can enhance the viability of randomly generated skin flaps by upregulating HIF-1α/VEGF signalling pathway, facilitating vascularization, inducing autophagy, suppressing cell apoptosis, and mitigating inflammation within the flap tissue.

BGP-15 alleviates LPS-induced depression-like behavior by promoting mitophagy

The high prevalence of major depressive disorder (MDD) frequently imposes severe constraints on psychosocial functioning and detrimentally impacts overall well-being. Despite the growing interest in the hypothesis of mitochondrial dysfunction, the precise mechanistic underpinnings and therapeutic strategies remain unclear and require further investigation. In this study, an MDD model was established in mice using lipopolysaccharide (LPS). Our research findings demonstrated that LPS exposure induced depressive-like behaviors and disrupted mitophagy by diminishing the mitochondrial levels of PINK1/Parkin in the brains of mice. Furthermore, LPS exposure evoked the activation of the NLRP3 inflammasome, accompanied by a notable elevation in the concentrations of pro-inflammatory factors (TNF-α, IL-1β, and IL-6). Additionally, neuronal apoptosis was stimulated through the JNK/p38 pathway. The administration of BGP-15 effectively nullified the impact of LPS, corresponding to the amelioration of depressive-like phenotypes and restoration of mitophagy, prevention of neuronal injury and inflammation, and suppression of reactive oxygen species (ROS)-mediated NLRP3 inflammasome activation. Furthermore, we elucidated the involvement of mitophagy in BGP-15-attenuated depressive-like behaviors using the inhibitors targeting autophagy (3-MA) and mitophagy (Mdivi-1). Notably, these inhibitors notably counteracted the antidepressant and anti-inflammatory effects exerted by BGP-15. Based on the research findings, it can be inferred that the antidepressant properties of BGP-15 in LPS-induced depressive-like behaviors could potentially be attributed to the involvement of the mitophagy pathway. These findings offer a potential novel therapeutic strategy for managing MDD.

Proteomics coupled transcriptomics reveals Slc34a1 and Slc34a3 downregulation as potential features of nephrotoxin-induced acute kidney injury

Acute kidney injury (AKI) stands as a prevalent and economically burdensome condition worldwide, yet its complex molecular mechanisms remain incompletely understood. To address this gap, our study employs a multifaceted approach, combining mass spectrometry and RNA sequencing technologies, to elucidate the intricate molecular landscape underlying nephrotoxin-induced AKI in mice by cisplatin- and LPS-induced. By examining the protein and RNA expression profiles, we aimed to uncover novel insights into the pathogenesis of AKI and identify potential diagnostic and therapeutic targets. Our results demonstrate significant down-regulation of Slc34a1 and Slc34a3, shedding light on their crucial roles in AKI pathology and highlighting their promise as actionable targets for diagnosis and treatment. This comprehensive analysis not only enhances our understanding of AKI pathophysiology but also offers valuable avenues for the development of targeted interventions to mitigate its clinical impact. SIGNIFICANCE: Nephrotoxicity acute kidney injury (AKI) is a common clinical condition whose pathogenesis is the process by which some drugs, chemicals or other factors cause damage to the kidneys, resulting in impaired kidney function. Although it has been proved that different nephrotoxic substances can affect the kidney through different pathways, whether they have a commonality has not been registered. Here, we combined transcriptomics and proteomics to study the molecular mechanism of LPS and cisplatin-induced nephrotoxic acute kidney injury finding that the down-regulation of Slc34a1 and Slc34a3 may be a critical link in nephrotoxic acute kidney injury, which can be used as a marker for its early diagnosis.

Hypoxia-inducible factor prolyl hydroxylase inhibitor alleviates heatstroke-induced acute kidney injury by activating BNIP3-mediated mitophagy

Hypoxia-induced inflammation and apoptosis are important pathophysiological features of heat stroke-induced acute kidney injury (HS-AKI). Hypoxia-inducible factor (HIF) is a key protein that regulates cell adaptation to hypoxia. HIF-prolyl hydroxylase inhibitor (HIF-PHI) stabilizes HIF to increase cell adaptation to hypoxia. Herein, we reported that HIF-PHI pretreatment significantly improved renal function, enhanced thermotolerance, and increased the survival rate of mice in the context of HS. Moreover, HIF-PHI could alleviate HS-induced mitochondrial damage, inflammation, and apoptosis in renal tubular epithelial cells (RTECs) by enhancing mitophagy in vitro and in vivo. By contrast, mitophagy inhibitors Mdivi-1, 3-MA, and Baf-A1 reversed the renoprotective effects of HIF-PHI. Mechanistically, HIF-PHI protects RTECs from inflammation and apoptosis by enhancing Bcl-2 adenovirus E18 19-kDa-interacting protein 3 (BNIP3)-mediated mitophagy, while genetic ablation of BNIP3 attenuated HIF-PHI-induced mitophagy and abolished HIF-PHI-mediated renal protection. Thus, our results indicated that HIF-PHI protects renal function by upregulating BNIP3-mediated mitophagy to improve HS-induced inflammation and apoptosis of RTECs, suggesting HIF-PHI as a promising therapeutic agent to treat HS-AKI.

ADT-OH exhibits anti-metastatic activity on triple-negative breast cancer by combinatorial targeting of autophagy and mitochondrial fission

High basal autophagy and enhanced mitochondrial fission in triple-negative breast cancer (TNBC) cells support cell migration and promote plasticity of cancer cell metabolism. Here, we suggest a novel combination therapy approach for the treatment of TNBC that targets Drp1-mediated mitochondrial fission and autophagy pathways. Hydrogen sulfide (H2S) mediates a myriad of biological processes, including autophagy and mitochondrial function. In this study, we demonstrated that 5-(4-hydroxyphenyl)-3H-1,2-dithiole-3-thione (ADT-OH), one of the most widely utilized sustained-release H2S donors, effectively suppresses metastasis of TNBC cells in the absence of proliferation inhibition in vitro and in vivo. ADT-OH treatment ameliorated autophagy flux by suppressing autophagosome formation and induced mitochondrial elongation through decreasing expression of dynamin-related protein 1 (Drp1) and increasing expression of mitochondrial fusion protein (Mfn2). At the same time, ADT-OH downregulated mitophagy flux and inhibited mitochondrial function, eventually leading to the inhibition of migration and invasion in TNBC cells. In vivo, intraperitoneal administration of ADT-OH revealed a potent anti-metastatic activity in three different animal models, the MDA-MB-231 orthotopic xenograft model, the 4T1-Luci orthotopic model and the 4T1-Luci tail vein metastasis model. However, ADT-OH has an extremely low water solubility, which is a significant barrier to its effectiveness. Thus, we demonstrated that the solubility of ADT-OH in water can be improved significantly by absorption with hydroxypropyl-β-cyclodextrin (CD). Remarkably, the obtained CD-ADT-OH demonstrated superior anti-cancer effect to ADT-OH in vivo. Altogether, this study describes a novel regulator of mammalian mitochondrial fission and autophagy, with potential utility as an experimental therapeutic agent for metastatic TNBC.

Neutrophil NLRP3 promotes cardiac injury following acute myocardial infarction through IL-1β production, VWF release and NET deposition in the myocardium

NLRP3 inflammasome has been implicated in neutrophil polarization and extrusion of neutrophil extracellular traps (NETs) in vitro and facilitates secretion of Il1-beta (IL-1β). Permanent ligation of the left anterior descending artery was used to induce MI in WT and NLRP3-/- mice as well as in NLRP3-/- recipient mice transfused with either WT or NLRP3-/- neutrophils. NLRP3 deficiency reduced infarct size to roughly a third of WT heart injury and preserved left ventricular (LV) function at 12 h after MI as assessed by echocardiography and triphenyltetrazolium chloride staining of live tissue. Transfusion of WT but not NLRP3-/- neutrophils after MI increased infarct size in NLRP3-/- mice and significantly reduced LV function. The key features of myocardial tissue in WT neutrophil transfused recipients were increased H3Cit-positive deposits with NET-like morphology and increased tissue levels of IL-1β and plasma levels of von Willebrand Factor (VWF). Flow cytometry analysis also revealed that neutrophil NLRP3 increased the number of labeled and transfused neutrophils in the bone marrow of recipient mice following MI. Our data suggest a key role for neutrophil NLRP3 in the production of IL-1β and deposition of NETs in cardiac tissue exacerbating injury following MI. We provide evidence for a link between neutrophil NLRP3 and VWF release likely enhancing thromboinflammation in the heart. Neutrophil NLRP3 deficiency conferred similar cardioprotective effects to general NLRP3 deletion in MI rendering anti-neutrophil NLRP3 therapy a promising target for early cardioprotective treatment.

Heyingwuzi formulation alleviates diabetic retinopathy by promoting mitophagy via the HIF-1α/BNIP3/NIX axis

BACKGROUND

Diabetic retinopathy (DR) is the primary cause of visual problems in patients with diabetes. The Heyingwuzi formulation (HYWZF) is effective against DR.

AIM

To determine the HYWZF prevention mechanisms, especially those underlying mitophagy.

METHODS

Human retinal capillary endothelial cells (HRCECs) were treated with high glucose (hg), HYWZF serum, PX-478, or Mdivi-1 in vitro. Then, cell counting kit-8, transwell, and tube formation assays were used to evaluate HRCEC proliferation, invasion, and tube formation, respectively. Transmission electron microscopy was used to assess mitochondrial morphology, and Western blotting was used to determine the protein levels. Flow cytometry was used to assess cell apoptosis, reactive oxygen species (ROS) production, and mitochondrial membrane potential. Moreover, C57BL/6 mice were established in vivo using streptozotocin and treated with HYWZF for four weeks. Blood glucose levels and body weight were monitored continuously. Changes in retinal characteristics were evaluated using hematoxylin and eosin, tar violet, and periodic acid-Schiff staining. Protein levels in retinal tissues were determined via Western blotting, immunohistochemistry, and immunostaining.

RESULTS

HYWZF inhibited excessive ROS production, apoptosis, tube formation, and invasion in hg-induced HRCECs via mitochondrial autophagy in vitro. It increased the mRNA expression levels of BCL2-interacting protein 3 (BNIP3), FUN14 domain-containing 1, BNIP3-like (BNIP3L, also known as NIX), PARKIN, PTEN-induced kinase 1, and hypoxia-inducible factor (HIF)-1α. Moreover, it downregulated the protein levels of vascular endothelial cell growth factor and increased the light chain 3-II/I ratio. However, PX-478 and Mdivi-1 reversed these effects. Additionally, PX-478 and Mdivi-1 rescued the effects of HYWZF by decreasing oxidative stress and apoptosis and increasing mitophagy. HYWZF intervention improved the symptoms of diabetes, tissue damage, number of acellular capillaries, and oxidative stress in vivo. Furthermore, in vivo experiments confirmed the results of in vitro experiments.

CONCLUSION

HYWZF alleviated DR and associated damage by promoting mitophagy via the HIF-1α/BNIP3/NIX axis.

Magnoflorine Ameliorates Chronic Kidney Disease in High-Fat and High-Fructose-Fed Mice by Promoting Parkin/PINK1-Dependent Mitophagy to Inhibit NLRP3/Caspase-1-Mediated Pyroptosis

Excessive intake of fat and fructose in Western diets has been confirmed to induce renal lipotoxicity, thereby driving the progression of chronic kidney disease (CKD). This study was conducted to evaluate the efficacy of magnoflorine in a CKD mouse model subjected to high-fat and high-fructose diets. Our results demonstrated that magnoflorine treatment ameliorated abnormal renal function indices (serum creatinine, urea nitrogen, uric acid, and urine protein) in high-fat- and high-fructose-fed mice. Histologically, renal tubular cell steatosis, lipid deposition, tubular dilatation, and glomerular fibrosis were significantly reduced by the magnoflorine treatment in these mice. Mechanistically, magnoflorine promotes Parkin/PINK1-mediated mitophagy, thereby inhibiting NLRP3/Caspase-1-mediated pyroptosis. Consistent findings were observed in the palmitic acid-incubated HK-2 cell model. Notably, both silencing of Parkin and the use of a mitophagy inhibitor reversed the inhibitory effect of magnoflorine on NLRP3 inflammasome activation in vitro. Therefore, the present study provides compelling evidence that magnoflorine improves renal injury in high-fat- and high-fructose-fed mice by promoting Parkin/PINK1-dependent mitophagy to inhibit NLRP3 inflammasome activation and pyroptosis. Our findings suggest that dietary supplementation with magnoflorine and magnoflorine-rich foods (such as magnolia) might be an effective strategy for the prevention of CKD.

Activation of lipophagy is required for RAB7 to regulate ferroptosis in sepsis-induced acute kidney injury

Sepsis-induced acute kidney injury (S-AKI) is the most common type of acute kidney injury (AKI), accompanied by elevated morbidity and mortality rates. This study investigated the mechanism by which lipid droplets (LDs) degraded via autophagy (lipophagy)required for RAB7 regulated ferroptosis in the pathogenesis of S-AKI. Here, we constructed the S-AKI model in vitro and in vivo to elucidate the potential relationship of lipophagy and ferroptosis, and we first confirmed that the activation of lipophagy promoted renal tubular epithelial cell ferroptosis and renal damage in S-AKI. The results showed that lipopolysaccharide (LPS) induced a marked increase in lipid peroxidation and ferroptosis, which were rescued by ferrstain-1 (Fer-1), an inhibitor of ferroptosis. In addition, LPS induced the remarkable activation of RAB7-mediated lipophagy. Importantly, silencing RAB7 alleviated LPS-induced lipid peroxidation and ferroptosis. Thus, the present study demonstrated the potential significant role of ferroptosis and lipophagy in sepsis-induced AKI, and contributed to better understanding of the pathogenesis and treatment targets of AKI.

Arsenic exposure induced renal fibrosis via regulation of mitochondrial dynamics and the NLRP3-TGF-β1/SMAD signaling pathway

Environmental arsenic exposure is one of the major global public health problems. Studies have shown that arsenic exposure can cause renal fibrosis, but the underlying mechanism is still unclear. Integrating the in vivo and in vitro models, this study investigated the potential molecular pathways for arsenic-induced renal fibrosis. In this study, SD rats were treated with 0, 5, 25, 50, and 100 mg/L NaAsO2 for 8 weeks via drinking water, and HK2 cells were treated with different doses of NaAsO2 for 48 h. The in vivo results showed that arsenic content in the rats' kidneys increased as the dose increased. Body weight decreased and kidney coefficient increased at 100 mg/L. As a response to the elevated NaAsO2 dose, inflammatory cell infiltration, renal tubular injury, glomerular atrophy, tubulointerstitial hemorrhage, and fibrosis became more obvious indicated by HE and Masson staining. The kidney transcriptome profiles further supported the protein-protein interactions involved in NaAsO2-induced renal fibrosis. The in vivo results, in together with the in vitro experiments, have revealed that exposure to NaAsO2 disturbed mitochondrial dynamics, promoted mitophagy, activated inflammation and the TGF-β1/SMAD signaling pathway, and finally resulted in fibrosis. In summary, arsenic exposure contributed to renal fibrosis via regulating the mitochondrial dynamics and the NLRP3-TGF-β1/SMAD signaling axis. This study presented an adverse outcome pathway for the development of renal fibrosis due to arsenic exposure through drinking water.

The role of mitochondrial dysfunction in kidney injury and disease

Mitochondria are the main sites of aerobic respiration in the cell and mainly provide energy for the organism, and play key roles in adenosine triphosphate (ATP) synthesis, metabolic regulation, and cell differentiation and death. Mitochondrial dysfunction has been identified as a contributing factor to a variety of diseases. The kidney is rich in mitochondria to meet energy needs, and stable mitochondrial structure and function are essential for normal kidney function. Recently, many studies have shown a link between mitochondrial dysfunction and kidney disease, maintaining mitochondrial homeostasis has become an important target for kidney therapy. In this review, we integrate the role of mitochondrial dysfunction in different kidney diseases, and specifically elaborate the mechanism of mitochondrial reactive oxygen species (mtROS), autophagy and ferroptosis involved in the occurrence and development of kidney diseases, providing insights for improved treatment of kidney diseases.

Inhibition of NLRP3 inflammasome by MCC950 under hypoxia alleviates photoreceptor apoptosis via inducing autophagy in Müller glia

NLRP3 inflammasome activation has emerged as a critical initiator of inflammatory response in ischemic retinopathy. Here, we identified the effect of a potent, selective NLRP3 inhibitor, MCC950, on autophagy and apoptosis under hypoxia. Neonatal mice were exposed to hyperoxia for 5 days to establish oxygen-induced retinopathy (OIR) model. Intravitreal injection of MCC950 was given, and then autophagy and apoptosis markers were assessed. Retinal autophagy, apoptosis, and related pathways were evaluated by western blot, immunofluorescent labeling, transmission electron microscopy, and TUNEL assay. Autophagic activity in Müller glia after NLRP3 inflammasome inhibition, together with its influence on photoreceptor death, was studied using western blot, immunofluorescence staining, mRFP-GFP-LC3 adenovirus transfection, cell viability, proliferation, and apoptosis assays. Results showed that activation of NLRP3 inflammasome in Müller glia was detected in OIR model. MCC950 could improve impaired retinal autophagic flux and attenuate retinal apoptosis while it regulated the retinal AMPK/mTOR/ULK-1 pathway. Suppressed autophagy and depressed proliferation capacity resulting from hypoxia was promoted after MCC950 treatment in Müller glia. Inhibition of AMPK and ULK-1 pathway significantly interfered with the MCC950-induced autophagy activity, indicating MCC950 positively modulated autophagy through AMPK/mTOR/ULK-1 pathway in Müller cells. Furthermore, blockage of autophagy in Müller glia significantly induced apoptosis in the cocultured 661W photoreceptor cells, whereas MCC950 markedly preserved the density of photoreceptor cells. These findings substantiated the therapeutic potential of MCC950 against impaired autophagy and subsequent apoptosis under hypoxia. Such protective effect might involve the modulation of AMPK/mTOR/ULK-1 pathway. Targeting NLRP3 inflammasome in Müller glia could be beneficial for photoreceptor survival under hypoxic conditions.

Inhibition of Drp1-mediated mitochondrial fission improves contrast-induced acute kidney injury by targeting the mROS-TXNIP-NLRP3 inflammasome axis

Acute kidney injury (AKI) is a critical complication known for their extremely high mortality rate and lack of effective clinical therapy. Disorders in mitochondrial dynamics possess a pivotal role in the occurrence and progression of contrast-induced nephropathy (CIN) by activating NLRP3 inflammasome. The activation of dynamin-related protein-1 (Drp1) can trigger mitochondrial dynamic disorders by regulating excessive mitochondrial fission. However, the precise role of Drp1 during CIN has not been clarified. In vivo experiments revealed that inhibiting Drp1 through Mdivi-1 (one selective inhibitor of Drp1) can significantly decrease the expression of p-Drp1 (Ser616), mitochondrial p-Drp1 (Ser616), mitochondrial Bax, mitochondrial reactive oxygen species (mROS), NLRP3, caspase-1, ASC, TNF-α, IL-1β, interleukin (IL)-18, IL-6, creatinine (Cr), malondialdehyde (MDA), blood urea nitrogen (BUN), and KIM-1. Moreover, Mdivi-1 reduced kidney pathological injury and downregulated the interaction between NLRP3 and thioredoxin-interacting protein (TXNIP), which was accompanied by decreased interactions between TRX and TXNIP. This resulted in increasing superoxide dismutase (SOD) and CAT activity, TRX expression, up-regulating mitochondrial membrane potential, and augmenting ATP contents and p-Drp1 (Ser616) levels in the cytoplasm. However, it did not bring impact on the expression of p-Drp1 (Ser637) and TXNIP. Activating Drp-1though Acetaldehyde abrogated the effects of Mdivi-1. In addition, the results of in vitro studies employing siRNA-Drp1 and plasmid-Drp1 intervention in HK-2 cells treated with iohexol were consistent with the in vivo experiments. Our findings revealed inhibiting Drp1 phosphorylation at Ser616 could ameliorate iohexol -induced acute kidney injury though alleviating the activation of the TXNIP-NLRP3 inflammasome pathway.

BMAL1 alleviates myocardial damage in sepsis by activating SIRT1 signaling and promoting mitochondrial autophagy

BACKGROUND

Brain and muscle arnt-like protein-1 (BMAL1) deficiency is associated with myocardial dysfunction and suppressed sirtuin 1 (SIRT1). However, whether BMAL1 promotes mitophagy via SIRT1 to alleviate myocardial injury in sepsis remains unknown.

METHODS

An in vitro myocardial injury model was established using lipopolysaccharide (LPS)-treated H9C2 cells. Knockdown or overexpression of genes was performed using plasmid transfection. Gene and protein expression was assessed by qRT-PCR and Western blot, respectively. Cell proliferation was evaluated using cell counting kit-8, and cellular apoptosis and reactive oxygen species (ROS) levels were analyzed using flow cytometry. An in vivo myocardial injury model of sepsis was established by cecal ligation and puncture in rats. Myocardial function was characterized by analyzing the damage-associated proteins, inflammatory factors, ejection fraction, and fraction shortening.

RESULTS

sgBMAL1 significantly decreased BMAL1 levels and remarkably increased the sensitivity of H9C2 cells to LPS stimulation, consequently enhancing LPS-induced apoptosis, inflammation, and ROS levels. These effects were further attenuated by BMAL1 overexpression. BMAL1 knockdown inhibited the expression of SIRT1 and mitophagy-associated proteins. SIRT1 overexpression reversed the enhancement of shBMAL1 on cell proliferation and inflammation. In the rat model of sepsis, BMAL1 overexpression decreased the myocardial injury-associated proteins to recover the myocardial function and suppressed inflammatory activities by promoting mitophagy via SIRT1.

CONCLUSION

BMAL1 enhances mitophagy dependent on SIRT1, thereby alleviating myocardial injury in sepsis.