The HIF-1/ BNIP3 pathway mediates mitophagy to inhibit the pyroptosis of fibroblast-like synoviocytes in rheumatoid arthritis

Study on the effect of deer bone in improving rheumatoid arthritis based on the "drug-target-pathway" association network

ETHNOPHARMACOLOGICAL RELEVANCE

Deer bone is rich in proteins, free amino acids, chondroitin, organic calcium, phosphorus ions, and other active components. Deer bone had been used widely in antiquity and were first compiled in renowned ancient masterpiece 'Mingyi Bielu ()' written by Hongjing Tao. The deer bone is recorded as non-toxic and has the effects of replenishing bones, strengthening sinews, expelling wind-dampness from the body, promoting muscle growth, and healing wounds. Modern pharmacological research suggests that deer bone can help promote bone density and enhance bone strength, making it potentially valuable for the prevention and treatment of diseases such as rheumatoid arthritis and osteoporosis. However, current studies on the component analysis and pharmacological effects of deer bone against rheumatoid arthritis (RA) are incomplete, which to some extent hinders the development and clinical application of deer bone drugs.

AIM OF THE STUDY

The components of deer bone were elucidated by label-free proteomics, and the drug-target-pathway association network was established by network pharmacology. The in vitro validation of the pathway provides a theoretical basis for deer bone as a potential therapeutic drug for rheumatoid arthritis, and also lays a solid foundation for the subsequent clinical application of the in vitro experiments established through serum pharmacology.

MATERIALS AND METHODS

We performed extraction of deer bone using traditional water extraction methods and employed label-free proteomics technology to identify and conduct bioinformatics analysis on the proteins and peptides in the deer bone hot water extract (DBHE). These components were considered potential drug targets, and we constructed a "drug-target-pathway" association network. Analysis revealed that the HIF-1 signaling pathway may be pivotal in DBWE's effect on RA. Hypoxia influences the occurrence and development of ferroptosis through various mechanisms. Therefore, we hypothesized that DBWE might induce ferroptosis, promoting apoptosis in RA-FLS under hypoxic conditions, thereby alleviating RA. Therefore, we performed flow cytometry, ELISA, immunofluorescence, RT-qPCR, and western blotting based on molecular docking. Considering the overall effect of drug metabolism post-ingestion, we used serum pharmacology to prepare serum for cellular administration.

RESULTS

It showed that DBWE reduces inflammation and synovial proliferation by inhibiting HO-1, increasing ROS production, upregulating ACSL4 expression and inducing RA-FLS apoptosis in hypoxic conditions. This study reveals the potential mechanism by which DBWE modulates ferroptosis to attenuate synovial proliferation in a hypoxic microenvironment and improve RA.

CONCLUSION

These findings not only provide a theoretical basis for deer bone as a potential therapeutic agent for RA, but also lay a solid foundation for subsequent clinical application through in vitro experiments established by serum pharmacology.

BNIP3-mediated mitophagy aggravates placental injury in preeclampsia via NLRP1 inflammasome

Introduction

Preeclampsia (PE) is a hypertensive disorder of pregnancy characterized by pronounced placental oxidative stress and inflammatory damage. However, the contribution of mitophagy to inflammation-induced placental injury in PE remains unclear.

Methods

Human placenta samples were collected from 15 normal pregnant women and 15 preeclampsia pregnant women. Protein expression was analyzed by western blotting, while immunofluorescence staining was employed to localize inflammatory mediators. Mitochondrial reactive oxygen species were quantified using MitoSOX. The concentrations of pro-inflammatory cytokines were quantified using ELISA, and ultrastructural alterations were evaluated by transmission electron microscopy. To investigate molecular mechanisms in vivo, a PE mouse model was established via daily subcutaneous administration of L-NAME, followed by tail vein delivery of AAV9 carrying shRNA for targeted gene knockdown.

Results

In this study, we demonstrate that BNIP3-mediated mitophagy and NLRP1 inflammasome activation occur in an L-NAME-induced PE mouse model and human PE placenta. The results also indicate that knockdown of BNIP3 abolishes mitophagy and NLRP1 inflammasome activation in JEG3 cells in H/R condition, suggesting a positive regulatory role for the BNIP3 in controlling mitophagy and NLRP1-dependent inflammation. Furthermore, silencing BNIP3 leads to a significant reduction in mitochondrial damage and mtROS production. Treatment with MitoTEMPO after BNIP3 silencing further decreases the expression of NLRP1, while overexpression of NLRP1 nullifies the impact of BNIP3 knockdown. Additionally, knockdown of BNIP3 alleviates placental injury in the PE mouse model.

Discussion

These findings reveal a novel mechanism through which BNIP3-mediated mitophagy exacerbates H/R-induced placental injury by inducing mtROS production and activating the NLRP1 inflammasome in PE.

Hypoxia-Inducible Factor-1α Regulates BNIP3-Dependent Mitophagy and Mediates Metabolic Reprogramming Through Histone Lysine Lactylation Modification to Affect Glioma Proliferation and Invasion

OBJECTIVE

Gliomas are the predominant form of malignant brain tumors. We investigated the mechanism of hypoxia-inducible factor-1α (HIF-1α) affecting glioma metabolic reprogramming, proliferation and invasion.

METHODS

Human glioma cell U87 was cultured under hypoxia and treated with small interfering (si)HIF-1α, si-B cell lymphoma-2/adenovirus E1B 19-kDa interacting protein 3 (siBNIP3), si-YT521-B homology domain 2 (siYTHDF2), 3-methyladenine and 2-deoxyglucose, with exogenous sodium lactate-treated normally-cultured cells as a lactate-positive control. Cellular hexokinase 2, lactate dehydrogenase A and pyruvate dehydrogenase kinase 1 enzyme activities, glucose uptake, and levels of lactic acid and adenosine triphosphate (ATP), and HIF-1α, glycolysis-related proteins, mitophagy-related proteins, histone H3 lysine 18 lactylation (H3K18la) and YTHDF2 were determined by ELISA, 2-NBDG, kits, and Western blot. Extracellular acidification rate (ECAR), and cell proliferation, invasion, apoptosis and mitophagy were evaluated by extracellular flux analysis, CCK-8, Transwell, flow cytometry, and immunofluorescence staining. H3K18la-YTHDF2 relationship and YTHDF2-BNIP3 interaction were assessed by ChIP and Co-IP assays.

RESULTS

Hypoxia-induced highly-expressed HIF-1α in glioma cells increased glycolysis-related protein levels, glycolytic enzyme activities, glucose uptake, lactic acid production, ATP level and ECAR, thereby promoting metabolic reprogramming, invasion and proliferation. HIF-1α mediated metabolic reprogramming, proliferation and invasion through BNIP3-dependent mitophagy, which were partly negated by mitophagy inhibition. HIF-1α induced histone Kla modification to upregulate YTHDF2. YTHDF2 downregulation impeded YTHDF2-BNIP3 interaction and inhibited HIF-1α-induced BNIP3-dependent mitophagy, curbing glioma cell metabolic reprogramming, proliferation and invasion.

CONCLUSIONS

Hypoxia-induced high HIF-1α expression upregulated YTHDF2 through hH3K18la modification, enhanced YTHDF2-BNIP3 interaction, and regulated BNIP3-dependent mitophagy-mediated metabolic reprogramming to affect glioma proliferation and invasion.

Ferroptosis and pyroptosis are connected through autophagy: a new perspective of overcoming drug resistance

Drug resistance is a common challenge in clinical tumor treatment. A reduction in drug sensitivity of tumor cells is often accompanied by an increase in autophagy levels, leading to autophagy-related resistance. The effectiveness of combining chemotherapy drugs with autophagy inducers/inhibitors has been widely confirmed, but the mechanisms are still unclear. Ferroptosis and pyroptosis can be affected by various types of autophagy. Therefore, ferroptosis and pyroptosis have crosstalk via autophagy, potentially leading to a switch in cell death types under certain conditions. As two forms of inflammatory programmed cell death, ferroptosis and pyroptosis have different effects on inflammation, and the cGAS-STING signaling pathway is also involved. Therefore, it also plays an important role in the progression of some chronic inflammatory diseases. This review discusses the relationship between autophagy, ferroptosis and pyroptosis, and attempts to uncover the reasons behind the evasion of tumor cell death and the nature of drug resistance.

Salidroside ameliorates macrophages lipid accumulation and atherosclerotic plaque by inhibiting Hif-1α-induced pyroptosis

BACKGROUND

Hipoxia-inducible factor 1 alpha (Hif-1α) is a significant risk factor for atherosclerotic cardiovascular disease. Salidroside (SAL) has demonstrated anti-oxidative and anti-cardiovascular disease effects. Currently, there are no relevant studies investigating the interaction between SAL and Hif-1α in the progression of atherosclerosis.

METHODS

Hif-1α was either knocked down or upregulated in Ana-1 macrophages-derived foam cells, and atherosclerosis ApoE-/- mice were treated with or without SAL. A Protein-protein network involving Hif-1α and pyroptosis-related genes was identified through bioinformatic analysis and validated in human vascular tissues. The Oil Red O and DiI staining were used to detect the intracellular ox-LDL accumulation. The HE and Oil Red O staining were employed to evaluate atherosclerotic plaque in vivo. The levels of relevant molecules were quantified using WB, qRT-PCR, ELISA, and immunohistochemistry. The target proteins of SAL were identified through Molecular docking and Cell Thermal Shift Assay (CESTA).

RESULTS

Both Hif-1α knockdown and SAL treatment markedly reduced lipid accumulation in macrophages-derived foam cells. Hif-1α was closely associated with Caspase1, Gsdmd, NRLP3, and IL-1β, and co-located in CD86+ macrophages-derived foam cells within atherosclerotic plaque. SAL inhibited Hif-1α-induced Caspase-1-dependent pyroptosis and lipid accumulation by directly bonding to Hif-1α. In vivo, SAL treatment decreased atherosclerotic plaque and improved plasma lipid profiles. Furthermore, SAL reduced M1 macrophages infiltration and the levels of Hif-1α, C-Caspase1, Gsdmd-N, NRLP3, IL-18, and IL-1β in atherosclerotic plaque.

CONCLUSION

SAL alleviated the lipid accumulation in macrophages and atherosclerotic plaques by inhibiting pyroptosis pathway via directly binding to Hif-1α, which may be a promising therapeutic strategy for AS treatment.

FOXO3 as a potential diagnostic biomarker for autophagy in rheumatoid arthritis: A bioinformatics study

This study aimed to identify genes associated with autophagy and potential diagnostic biomarkers by comparing the gene expression profiles of synovial tissues in patients with rheumatoid arthritis (RA) and healthy individuals, aiming to offer new insights for clinical treatment strategies. We used publicly available datasets to analyze differentially expressed genes (DEGs) between the synovial tissue of RA patients and healthy individuals. Then, we intersected these DEGs with autophagy-related genes to identify autophagy genes in the synovial tissue of RA patients. We further analyzed the biological processes and functions of these genes. Furthermore, we used machine learning to identify characteristic autophagy genes in RA synovial tissue. Finally, we examined the differential expression of these characteristic genes in the blood of RA patients using an external dataset. Our study identified FOXO3 as a potential biomarker for diagnosing RA. FOXO3 gene expression was downregulated in both the synovial tissue and blood of RA patients, suggesting its involvement in multiple biological processes such as local inflammation, oxidative stress, metabolic processes, and immune responses. Our findings suggest that FOXO3 may be a novel biomarker for the clinical diagnosis of RA and may play a crucial role in the pathogenesis of RA. The study provides new insights into the molecular mechanisms of RA and potential new therapeutic targets.

IRF1-mediated upregulation of PARP12 promotes cartilage degradation by inhibiting PINK1/Parkin dependent mitophagy through ISG15 attenuating ubiquitylation and SUMOylation of MFN1/2

Osteoarthritis (OA) is an age-related cartilage-degenerating joint disease. Mitochondrial dysfunction has been reported to promote the development of OA. Poly (ADP-ribose) polymerase family member 12 (PARP12) is a key regulator of mitochondrial function, protein translation, and inflammation. However, the role of PARP12 in OA-based cartilage degradation and the underlying mechanisms are relatively unknown. Here, we first demonstrated that PARP12 inhibits mitophagy and promotes OA progression in human OA cartilage and a monosodium iodoacetate-induced rat OA model. Using mass spectrometry and co-immunoprecipitation assay, PARP12 was shown to interact with ISG15, upregulate mitofusin 1 and 2 (MFN1/2) ISGylation, which downregulated MFN1/2 ubiquitination and SUMOylation, thereby inhibiting PINK1/Parkin-dependent chondrocyte mitophagy and promoting cartilage degradation. Moreover, inflammatory cytokine-induced interferon regulatory factor 1 (IRF1) activation was required for the upregulation of PARP12 expression, and it directly bound to the PARP12 promoter to activate transcription. XAV-939 inhibited PARP12 expression and suppressed OA pathogenesis in vitro and in vivo. Clinically, PARP12 can be used to predict the severity of OA; thus, it represents a new target for the study of mitophagy and OA progression. In brief, the IRF1-mediated upregulation of PARP12 promoted cartilage degradation by inhibiting PINK1/Parkin-dependent mitophagy via ISG15-based attenuation of MFN1/2 ubiquitylation and SUMOylation. Our data provide new insights into the molecular mechanisms underlying PARP12-based regulation of mitophagy and can facilitate the development of therapeutic strategies for the treatment of OA.

Mitophagy-associated programmed neuronal death and neuroinflammation

Mitochondria are crucial organelles that play a central role in cellular metabolism and programmed cell death in eukaryotic cells. Mitochondrial autophagy (mitophagy) is a selective process where damaged mitochondria are encapsulated and degraded through autophagic mechanisms, ensuring the maintenance of both mitochondrial and cellular homeostasis. Excessive programmed cell death in neurons can result in functional impairments following cerebral ischemia and trauma, as well as in chronic neurodegenerative diseases, leading to irreversible declines in motor and cognitive functions. Neuroinflammation, an inflammatory response of the central nervous system to factors disrupting homeostasis, is a common feature across various neurological events, including ischemic, infectious, traumatic, and neurodegenerative conditions. Emerging research suggests that regulating autophagy may offer a promising therapeutic avenue for treating certain neurological diseases. Furthermore, existing literature indicates that various small molecule autophagy regulators have been tested in animal models and are linked to neurological disease outcomes. This review explores the role of mitophagy in programmed neuronal death and its connection to neuroinflammation.

Mitochondrial dysfunction induced by HIF-1α under hypoxia contributes to the development of gastric mucosal lesions

INTRODUCTION

Hypoxia is an important characteristic of gastric mucosal diseases, and hypoxia-inducible factor-1α (HIF-1α) contributes to microenvironment disturbance and metabolic spectrum abnormalities. However, the underlying mechanism of HIF-1α and its association with mitochondrial dysfunction in gastric mucosal lesions under hypoxia have not been fully clarified.

OBJECTIVES

To evaluate the effects of hypoxia-induced HIF-1α on the development of gastric mucosal lesions.

METHODS

Portal hypertensive gastropathy (PHG) and gastric cancer (GC) were selected as representative diseases of benign and malignant gastric lesions, respectively. Gastric tissues from patients diagnosed with the above diseases were collected. Portal hypertension (PHT)-induced mouse models in METTL3 mutant or NLRP3-deficient littermates were established, and nude mouse gastric graft tumour models with relevant inhibitors were generated. The mechanisms underlying hypoxic condition, mitochondrial dysfunction and metabolic alterations in gastric mucosal lesions were further analysed.

RESULTS

HIF-1α, which can mediate mitochondrial dysfunction via upregulation of METTL3/IGF2BP3-dependent dynamin-related protein 1 (Drp1) N6-methyladenosine modification to increase mitochondrial reactive oxygen species (mtROS) production, was elevated under hypoxic conditions in human and mouse portal hypertensive gastric mucosa and GC tissues. While blocking HIF-1α with PX-478, inhibiting Drp1-dependent mitochondrial fission via mitochondrial division inhibitor 1 (Mdivi-1) treatment or METTL3 mutation alleviated this process. Furthermore, HIF-1α influenced energy metabolism by enhancing glycolysis via lactate dehydrogenase A. In addition, HIF-1α-induced Drp1-dependent mitochondrial fission also enhanced glycolysis. Drp1-dependent mitochondrial fission and enhanced glycolysis were associated with alterations in antioxidant enzyme activity and dysfunction of the mitochondrial electron transport chain, resulting in massive mtROS production, which was needed for activation of NLRP3 inflammasome to aggravate the development of the PHG and GC.

CONCLUSIONS

Under hypoxic conditions, HIF-1α enhances mitochondrial dysfunction via Drp1-dependent mitochondrial fission and influences the metabolic profile by altering glycolysis to increase mtROS production, which can trigger NLRP3 inflammasome activation and mucosal microenvironment alterations to contribute to the development of benign and malignant gastric mucosal lesions.