Targeting Ferroptosis in Bone-Related Diseases: Facts and Perspectives

Rosiglitazone retards the progression of iron overload-induced osteoarthritis by impeding chondrocyte ferroptosis

Ferroptosis is implicated in several diseases, including iron overload-induced osteoarthritis (IOOA), which is marked by oxidative stress, iron imbalance, and lipid peroxidation. Given rosiglitazone's (RSG) ability to inhibit lipid peroxidation and ferroptosis, this study aims to assess its therapeutic potential for treating IOOA. Our in vitro results show that RSG targets acyl-CoA synthetase long-chain family member 4 to mitigate impairments induced by interleukin-1 beta and ferric ammonium citrate, including cell apoptosis, senescence, inflammatory responses, extracellular matrix degradation, and ferroptosis. RSG reduced intracellular iron content, alleviated oxidative stress and lipid peroxidation, mitigated damage to membrane-bound organelles, and enhanced glucose transport. Additionally, pre-treatment with RSG imparted anti-ferroptotic properties to chondrocytes. In vivo, RSG alleviated cartilage degradation, inflammatory responses, and ferroptosis in mice with IOOA. In conclusion, RSG exhibits chondroprotective and anti-ferroptotic effects by suppressing lipid peroxidation and restoring iron homeostasis, highlighting its potential for treating IOOA.

Computational recognition of regulator genes and signature for ferroptosis with implications on immunological properties and clinical management of atopic dermatitis

Background

Atopic dermatitis (AD) is a common chronic dermatitis of autoimmune origin that considerably affects the quality of life of patients. Ferroptosis, a newly regulated form of cell death, is essential for inflammation-related damage-associated molecular patterns (DAMPs). In this study, we aimed to identify ferroptosis regulators relevant to AD pathogenesis and reveal the mechanisms by which ferroptosis regulates the pathogenesis of AD.

Methods

We analyzed the GEO AD cohorts (GSE16161, GSE32924, GSE107361, and GSE120721), identifying AD-related differentially expressed genes (DEGs) using edgeR. Co-expression and STRING database analyses were used to elucidate the interactions between DEGs and ferroptosis markers. Through functional enrichment analysis, we defined potential biological functions within the protein-protein interaction (PPI) network and developed FerrSig using LASSO regression. The utility of FerrSig in guiding the clinical management of AD was evaluated using the GSE32473 cohort. Subsequently, our in silico findings were confirmed, and mechanistic insights were expanded through both in vitro and in vivo studies, validating the relevance of FerrSig.

Results

In the GEO AD cohort, 278 DEGs were identified, including seven ferroptosis signature genes. Co-expression analysis and STRING database review revealed a 63-node PPI network linked to cell cycle and pro-inflammatory pathways. Four ferroptosis genes (ALOXE3, FABP4, MAP3K14, and EGR1) were selected to create FerrSig, which was significantly downregulated in samples collected from patients with AD. In addition, immune-related signaling pathways were significantly differentially enriched between the stratifications of samples collected from patients with AD with high and low ferritin levels, whereas in the GSE32473 cohort, FerrSig was significantly increased in cohorts effectively treated with pimecrolimus or betamethasone. Finally, in vitro and in vivo models showed a notable FerrSig decrease in patients with AD versus healthy control. Treatment with betamethasone and tacrolimus restored FerrSig, and the magnitude of the increase in FerrSig was higher in samples collected from patients with AD with better efficacy assessments. In addition, FerrSig was significantly positively correlated with the ferroptosis inhibitors GPX4 and SLC7A11 and negatively correlated with reactive oxygen species (ROS) levels and p-STAT3/STAT3. This implies that the FerrSig signature genes may regulate ferroptosis through the JAK/STAT3 signaling pathway.

Conclusion

Our study further explored the pathogenesis of AD, and FerrSig could serve as a potential biomarker for identifying AD morbidity risks and determining treatment efficacy.

IL-16 Mediates the Effect of Circulating Metabolites on Postmenopausal Osteoporosis: A Two-Step, Multivariable Mendelian Randomization Study

Objectives: This study aimed to explore the relationship between circulating metabolites and postmenopausal osteoporosis (PMOP) and to assess the mediating role of inflammatory factors. Methods: Utilizing summary-level data from genome-wide association studies (GWAS) and employing a Mendelian Randomization approach, a two-sample MR analysis was conducted to assess the relationship between circulating metabolites and PMOP. Additionally, a two-step MR was used to quantify the mediating impact of inflammatory factors on the effect of circulating metabolites on PMOP. Results: The results revealed a significant association between certain metabolites and the risk of PMOP, notably the ratio of free cholesterol to total lipids in very large VLDL particles (OR: 1.399, 95% CI: 1.002-1.954, p = 0.048) and IL-16 (OR: 0.773, 95% CI: 0.608-0.983, p = 0.036). IL-16 was found to partially mediate the impact of circulating metabolites on PMOP, with a mediation effect of 10.4%. Conclusion: This study underscores the crucial role of circulating metabolites and inflammatory factors in PMOP pathogenesis. A causal relationship between circulating metabolites and PMOP was established, with IL-16 mediating some effects. These findings hold promise for clinical applications in early detection, personalized medicine, and the identification of therapeutic targets for PMOP.

Ferroptosis: a novel mechanism of cell death in ophthalmic conditions

Ferroptosis, a new type of programmed cell death proposed in recent years, is characterized mainly by reactive oxygen species and iron-mediated lipid peroxidation and differs from programmed cell death, such as apoptosis, necrosis, and autophagy. Ferroptosis is associated with a variety of physiological and pathophysiological processes. Recent studies have shown that ferroptosis can aggravate or reduce the occurrence and development of diseases by targeting metabolic pathways and signaling pathways in tumors, ischemic organ damage, and other degenerative diseases related to lipid peroxidation. Increasing evidence suggests that ferroptosis is closely linked to the onset and progression of various ophthalmic conditions, including corneal injury, glaucoma, age-related macular degeneration, diabetic retinopathy, retinal detachment, and retinoblastoma. Our review of the current research on ferroptosis in ophthalmic diseases reveals significant advancements in our understanding of the pathogenesis, aetiology, and treatment of these conditions.

Ferroptosis and hepatocellular carcinoma: the emerging role of lncRNAs

Hepatocellular carcinoma is the most common form of primary liver cancer and poses a significant challenge to the medical community because of its high mortality rate. In recent years, ferroptosis, a unique form of cell death, has garnered widespread attention. Ferroptosis, which is characterized by iron-dependent lipid peroxidation and mitochondrial alterations, is closely associated with the pathological processes of various diseases, including hepatocellular carcinoma. Long non-coding RNAs (lncRNAs), are a type of functional RNA, and play crucial regulatory roles in a variety of biological processes. In this manuscript, we review the regulatory roles of lncRNAs in the key aspects of ferroptosis, and summarize the research progress on ferroptosis-related lncRNAs in hepatocellular carcinoma.

ATP-induced cell death: a novel hypothesis for osteoporosis

ATP-induced cell death has emerged as a captivating realm of inquiry with profound ramifications in the context of osteoporosis. This study unveils a paradigm-shifting hypothesis that illuminates the prospective involvement of ATP-induced cellular demise in the etiology of osteoporosis. Initially, we explicate the morphological attributes of ATP-induced cell death and delve into the intricacies of the molecular machinery and regulatory networks governing ATP homeostasis and ATP-induced cell death. Subsequently, our focus pivots towards the multifaceted interplay between ATP-induced cellular demise and pivotal cellular protagonists, such as bone marrow-derived mesenchymal stem cells, osteoblasts, and osteoclasts, accentuating their potential contributions to secondary osteoporosis phenotypes, encompassing diabetic osteoporosis, glucocorticoid-induced osteoporosis, and postmenopausal osteoporosis. Furthermore, we probe the captivating interplay between ATP-induced cellular demise and alternative modalities of cellular demise, encompassing apoptosis, autophagy, and necroptosis. Through an all-encompassing inquiry into the intricate nexus connecting ATP-induced cellular demise and osteoporosis, our primary goal is to deepen our comprehension of the underlying mechanisms propelling this malady and establish a theoretical bedrock to underpin the development of pioneering therapeutic strategies.