Hydrogen sulfide as a potent scavenger of toxicant acrolein

Muscarinic receptor drug trihexyphenidyl can alter growth of mesenchymal glioblastoma in vivo

Glioblastoma (GBM) is the most commonly occurring and most aggressive primary brain tumor. Transcriptomics-based tumor subtype classification has established the mesenchymal lineage of GBM (MES-GBM) as cancers with particular aggressive behavior and high levels of therapy resistance. Previously it was show that Trihexyphenidyl (THP), a market approved M1 muscarinic receptor-targeting oral drug can suppress proliferation and survival of GBM stem cells from the classical transcriptomic subtype. In a series of in vitro experiments, this study confirms the therapeutic potential of THP, by effectively suppressing the growth, proliferation and survival of MES-GBM cells with limited effects on non-tumor cells. Transcriptomic profiling of treated cancer cells identified genes and associated metabolic signaling pathways as possible underlying molecular mechanisms responsible for THP-induced effects. In vivo trials of THP in immunocompromised mice carry orthotopic MES-GBMs showed moderate response to the drug. This study further highlights the potential of THP repurposing as an anti-cancer treatment regimen but mode of action and d optimal treatment procedures for in vivo regimens need to be investigated further.

Hydrogen sulfide protects against toxicant acrolein-induced ferroptotic cell death in Sertoli cells

Acrolein (ACR) is a ubiquitous environmental pollutant and byproduct of lipid peroxidation that has been implicated in male infertility. However, the molecular mechanisms underlying ACR-induced toxicity in Sertoli cells remain unclear. Given its role in inducing oxidative stress, we examined whether ferroptosis, an iron-dependent form of regulated cell death, could mediate ACR toxicity in Sertoli cells. We also tested if hydrogen sulfide (H2S), which has antioxidant and ACR detoxifying properties, could protect Sertoli cells from ACR-induced ferroptosis. ACR exposure decreased Sertoli cell viability, increased protein carbonylation and p38 MAPK phosphorylation, indicating oxidative injury. ACR also depleted glutathione (GSH), downregulated the cystine importer SLC7A11, increased intracellular ferrous iron (Fe2+) and lipid peroxidation, suggesting activation of ferroptosis. Consistently, the ferroptosis inhibitor deferoxamine (DFO) markedly attenuates ACR-induced cell death. Further studies revealed that ACR-induced ferroptotic changes were prevented by exogenous H2S and exaggerated by inhibition of endogenous H2S production. Furthermore, H2S also suppressed GPX4 inhibitor RSL3-induced intracellular ACR accumulation and ferroptosis. In summary, our study demonstrates that ACR induces ferroptotic cell death in Sertoli cells, which can be prevented by H2S through multiple mechanisms. Targeting the H2S pathway may represent a therapeutic strategy to mitigate ACR-induced Sertoli cell injury and preserve male fertility.

Ferroptosis contributes to cyclophosphamide-induced hemorrhagic cystitis

Cyclophosphamide (CYP) is extensively used in tumor therapy, but its clinical application is limited by its toxic effects on the bladder. Since CYP-induced cystitis is believed to be mediated by acrolein (ACR), a product of lipid peroxidation that triggers ferroptosis, we hypothesized that ferroptosis might be an essential molecular mechanism underlying CYP-induced cystitis. The purpose of this study was to test this hypothesis. Intraperitoneal injection of CYP led to bladder hemorrhage and edema, along with increased oxidation, inflammation, and cell injury. Further analysis revealed these changes were associated with altered ferroptosis markers in the bladder, such as FPN1, ACSL4, SLC7A11, and GPX4, indicating the existence of ferroptosis. Administration of ferroptosis inhibitor dexrazoxane (DXZ) improved ferroptosis and prevented CYP-induced pathological changes in the bladder. Collectively, our study revealed that ferroptosis is an important mechanism underlying CYP-induced cystitis, and therapeutic approaches targeting ferroptosis could be developed to treat CYP-induced cystitis.

Hydrogen sulfide protects Sertoli cells against toxicant Acrolein-induced cell injury

Acrolein (ACR), a highly toxic α,β-unsaturated aldehyde, is considered to be a common mediator behind the reproductive injury induced by various factors. However, the understanding of its reproductive toxicity and prevention in reproductive system is limited. Given that Sertoli cells provide the first-line defense against various toxicants and that dysfunction of Sertoli cell causes impaired spermatogenesis, we, therefore, examined ACR cytotoxicity in Sertoli cells and tested whether hydrogen sulfide (H₂S), a gaseous mediator with potent antioxidative actions, could have a protective effect. Exposure of Sertoli cells to ACR led to cell injury, as indicated by reactive oxygen species (ROS) generation, protein oxidation, P38 activation and ultimately cell death that was prevented by antioxidant N-acetylcysteine (NAC). Further studies revealed that ACR cytotoxicity on Sertoli cells was significantly exacerbated by the inhibition of H₂S-synthesizing enzyme cystathionine γ-lyase (CSE), while significantly suppressed by H₂S donor Sodium hydrosulfide (NaHS). It was also attenuated by Tanshinone IIA (Tan IIA), an active ingredient of Danshen that stimulated H₂S production in Sertoli cells. Apart from Sertoli cells, H₂S also protected the cultured germ cells from ACR-initiated cell death. Collectively, our study characterized H₂S as endogenous defensive mechanism against ACR in Sertoli cells and germ cells. This property of H₂S could be used to prevent and treat ACR-related reproductive injury.

Mass Spectrometry Analysis of DNA and Protein Adducts as Biomarkers in Human Exposure to Cigarette Smoking: Acrolein as an Example

Acrolein is a major component in cigarette smoke and a product of endogenous lipid peroxidation. It is difficult to distinguish human exposure to acrolein from exogenous sources versus endogenous causes, as components in cigarette smoke can stimulate lipid peroxidation in vivo. Therefore, analysis of acrolein-induced DNA and protein adducts by the highly accurate, sensitive, and specific mass spectrometry-based methods is vital to estimate the degree of damage by this IARC Group 2A carcinogen. This Perspective reviews the analyses of acrolein-induced DNA and protein adducts in humans by mass spectrometry focusing on samples accessible for biomonitoring, including DNA from leukocytes and oral cells and abundant proteins from blood, i.e., hemoglobin and serum albumin.