TLR4-A Pertinent Player in Radiation-Induced Heart Disease?

Elucidating the mechanism of action of astragalus polysaccharide on ionizing radiation-induced myocardial damage based on network pharmacology and experimental research

Due to the unavoidable impact of ionizing radiation on the heart located near the mediastinum, varying degrees of myocardial damage may occur. As a result, the clinical application of radiotherapy in cancer treatment is significantly limited. However, the molecular mechanisms underlying radiation-induced heart disease (RIHD) are not yet fully understood, and there is a lack of disease-specific treatment strategies. Astragalus polysaccharide (APS), is an active compound abundant in the traditional Chinese herb Astragalus membranaceus (Fisch.) Bunge (AS), has been shown to have cardioprotective effects against various cardiovascular diseases. Thus, this study aims to investigate the potential cardioprotective effect of APS on RIHD and its underlying molecular mechanisms. The network pharmacology results indicated that 9 core genes were identified from the biological network of the effective components of AS acting on RIHD. The results of GO enrichment analysis showed that these hub genes were mainly involved in biological processes such as cell apoptosis, cell proliferation, inflammatory response, and response to external stimuli. The results of KEGG enrichment analysis showed that these hub genes mainly regulated the occurrence of RIHD through pathways such as the EGFR signaling pathway, PI3K/Akt signaling pathway, IL-17 signaling pathway, and so on. In molecular docking analysis, we found that AKT1 and mTOR had good and stable binding abilities with the three types of glucosides rich in AS. The results of in vitro and in vivo experiments all showed that APS could not only improve cardiac dysfunction, myocardial injury, inflammatory response, and myocardial fibrosis in RIHD rats, but also alleviated apoptosis and atrophy of H9C2 cells under ionizing radiation stimulation. In addition, we also found that APS improved the accumulation of autophagic flux induced by ionizing radiation, which could be confirmed by the reversal of Beclin1, p62, LC3B proteins and accelerated degradation of accumulated autophagic vesicles. Rapamycin (Rap) was a classic autophagy flux inducer that could attenuate the improvement effect of APS on H9C2 cell apoptosis under ionizing radiation stimulation. Finally, we found that APS could reverse the inhibition of PI3K/Akt/mTOR signaling pathway activity by ionizing radiation in vitro, thereby improving ionizing radiation-induced autophagy flux accumulation, cardiomyocyte apoptosis, and atrophy. All in all, this study provides important evidence for understanding the molecular mechanisms of the cross-talk between autophagy and apoptosis, and provides new directions and insights for APS combined with autophagy regulators as a therapeutic strategy for RIHD.

Hesperidin attenuates radiation-induced ovarian failure in rats: Emphasis on TLR-4/NF-ĸB signaling pathway

Young women suffering from premature ovarian failure after radiotherapy carry a huge burden in the field of cancer therapy including reproductive loss, emotional stress, and physical troubles that reduce their long-term quality of life. Hesperidin (HSP) exhibited antioxidant, anti-inflammatory, and anti-apoptotic properties. HSP enhanced in vitro follicular maturation and preserved in vivo ovarian stockpile. In this research, the role of HSP in radiation-induced POF in rats was investigated besides ascertaining its underlying mechanisms. Female Sprague-Dawley rats were arbitrarily allocated into four groups: control-group, ϒ-irradiated-group (3.2 Gy once on the 7th day), HSP-group (100 mg/kg, orally for 10 days), and HSP/ϒ-irradiated-group (ϒ-radiation was applied one hour after HSP). At the end of experiment, the whole ovaries were collected for histological and biochemical analyses. Administration of HSP preserved the ovarian histoarchitecture and follicular stock, retained ovarian weight, and conserved serum estradiol and AMH levels following radiation exposure. HSP ameliorated the ovarian oxidative damage mediated by radiation through augmenting the activities of glutathione peroxidase, glutathione reductase, and catalase antioxidant enzymes. HSP exhibited remarkable anti-inflammatory activity by downregulating the expression of ovarian TLR-4, NF-ĸB, and TNF-α. Moreover, HSP suppressed the apoptotic machinery triggered by radiation by reducing p53 and Bax while increasing Bcl-2 mRNA expressions alongside diminishing caspase-3 expression. Additionally, HSP regulated estrous cycle disorder of irradiated rats and improved their reproductive capacity reflected by enhancing pregnancy outcomes. Therefore, HSP represents an appealing candidate as an adjunct remedy for female cancer patients during radiotherapy protocols owing to its antioxidant, anti-inflammatory, anti-apoptotic, and hormone-regulatory effects.

Investigate the binding of pesticides with the TLR4 receptor protein found in mammals and zebrafish using molecular docking and molecular dynamics simulations

The widespread use of pesticides poses significant threats to both environmental and human health, primarily due to their potential toxic effects. The study investigated the cardiovascular toxicity of selected pesticides, focusing on their interactions with Toll-like receptor 4 (TLR4), an important part of the innate immune system. Using computational tools such as molecular docking, molecular dynamics (MD) simulations, principal component analysis (PCA), density functional theory (DFT) calculations, and ADME analysis, this study identified C160 as having the lowest binding affinity (-8.2 kcal/mol), followed by C107 and C165 (-8.0 kcal/mol). RMSD, RMSF, Rg, and hydrogen bond metrics indicated the formation of stable complexes between specific pesticides and TLR4. PCA revealed significant structural changes upon ligand binding, affecting stability and flexibility, while DFT calculations provided information about the stability, reactivity, and polarity of the compounds. ADME studies highlighted the solubility, permeability, and metabolic stability of C107, C160, and C165, suggesting their potential for bioavailability and impact on cardiovascular toxicity. C107 and C165 exhibit higher bioactivity scores, indicating favourable absorption, metabolism, and distribution properties. C165 also violated rule where molecular weight is greater than 500 g/mol. Further, DFT and NCI analysis of post MD conformations confirmed the binding of ligands at the binding pocket. The analysis shed light on the molecular mechanisms of pesticide-induced cardiovascular toxicity, aiding in the development of strategies to mitigate their harmful effects on human health.

Integrative analyses and validation of ferroptosis-related genes and mechanisms associated with cerebrovascular and cardiovascular ischemic diseases

BACKGROUND

There has been a gradual increase in the occurrence of cardiovascular and cerebrovascular ischemic diseases, particularly as comorbidities. Yet, the mechanisms underlying these diseases remain unclear. Ferroptosis has emerged as a potential contributor to cardio-cerebral ischemic processes. Therefore, this study investigated the shared biological mechanisms between the two processes, as well as the role of ferroptosis genes in cardio-cerebral ischemic damage, by constructing co-expression modules for myocardial ischemia (MI) and ischemic stroke (IS) and a network of protein-protein interactions, mRNA-miRNA, mRNA-transcription factors (TFs), mRNA-RNA-binding proteins (RBPs), and mRNA-drug interactions.

RESULTS

The study identified seven key genes, specifically ACSL1, TLR4, ADIPOR1, G0S2, PDK4, HP, PTGS2, and subjected them to functional enrichment analysis during ischemia. The predicted miRNAs were found to interact with 35 hub genes, and interactions were observed between 11 hub genes and 30 TF transcription factors. Additionally, 10 RBPs corresponding to 16 hub genes and 163 molecular compounds corresponding to 30 hub genes were identified. This study also clarified the levels of immune infiltration between MI and IS and different subtypes. Finally, we identified four hub genes, including TLR4, by using a diagnostic model constructed by Least Absolute Shrinkage and Selection Operator (LASSO) regression analysis; ADIPOR1, G0S2, and HP were shown to have diagnostic value for the co-pathogenesis of MI and cerebral ischemia by both validation test data and RT-qPCR assay.

CONCLUSIONS

To the best our knowledge, this study is the first to utilize multiple algorithms to comprehensively analyze the biological processes of MI and IS from various perspectives. The four hub genes, TLR4, ADIPOR1, G0S2, and HP, have proven valuable in offering insights for the investigation of shared injury pathways in cardio-cerebral injuries. Therefore, these genes may serve as diagnostic markers for cardio-cerebral ischemic diseases.

Mobitz II Atrioventricular Block Following Intracardiac Radiation to the Right Ventricular Outflow Tract

Cardiac complications from mediastinal radiotherapy are much more prevalent than in years past and are becoming a significant cause of morbidity and mortality in these patients following treatment. We describe a patient with metastatic lung adenosquamous carcinoma extending to the right ventricular outflow tract who would develop a Mobitz type II atrioventricular block following intracardiac radiation therapy requiring permanent pacemaker placement.