Evidence for the systemic diffusion of (2-chloroethyl)-ethyl-sulfide, a sulfur mustard analog, and its deleterious effects in brain

Glutathione conjugation of sesquimustard: in vitro investigation of potential biomarkers

Sesquimustard (Q) is a powerful blistering agent that contains additional sulfur atoms. Sulfur mustard causes covalent bonding by alkylating nucleophilic groups of biologically important macromolecules such as lipids, proteins, DNA, or RNA. Most cells maintain relatively high amounts of a unique tripeptide called glutathione (GSH) (γ-glutamyl-cysteinyl glycine), which possesses a free thiol group, to prevent unwanted reactions caused by reactive chemical entities. Moreover, these thiol groups on cysteines (Cys) are the main target for alkylation. Although Q is the most potent vesicant among sulfur mustards, research studies identifying biomarkers of Q are very limited. Therefore, here in this study, we aimed to identify the GSH and Cys conjugates of Q using mass spectrometric methods and to observe the formation of these conjugates in HaCat cell culture following exposure to different doses. We identified four different conjugates of Q, which are bis-glutathionyl ethylthioethylthioethyl conjugate (GSH-ETETE-GSH), hydroxyethylthioethylthioethyl glutathione conjugate (HETETE-GSH), bis-cysteinyl ethylthioethylthioethyl conjugate (Cys-ETETE-Cys), and hydroxyethylthioethylthioethyl cysteine conjugate (HETETE-Cys). The identity of the conjugates was elucidated using liquid chromatography-high-resolution mass spectrometry (LC-HRMS). We also investigated changes in conjugate formation with exposure concentration and time elapsed after exposure in the cell culture. After exposure, GSH conjugates decreased until 1st hour, while Cys conjugates increased until 6th hour. We also observed that conjugate formation depended on the concentration of Q. This is the first study to elucidate the conjugates of Q dependent on GSH conjugation. As biomarkers are essential tools for evaluating exposure to Q, this study contributes to the limited number of studies identifying biomarkers for Q.

Life-Cycle-Dependent Toxicities of Mono- and Bifunctional Alkylating Agents in the 3R-Compliant Model Organism C. elegans

Caenorhabditis elegans (C. elegans) is gaining recognition and importance as an organismic model for toxicity testing in line with the 3Rs principle (replace, reduce, refine). In this study, we explored the use of C. elegans to examine the toxicities of alkylating sulphur mustard analogues, specifically the monofunctional agent 2-chloroethyl-ethyl sulphide (CEES) and the bifunctional, crosslinking agent mechlorethamine (HN2). We exposed wild-type worms at different life cycle stages (from larvae L1 to adulthood day 10) to CEES or HN2 and scored their viability 24 h later. The susceptibility of C. elegans to CEES and HN2 paralleled that of human cells, with HN2 exhibiting higher toxicity than CEES, reflected in LC50 values in the high µM to low mM range. Importantly, the effects were dependent on the worms' developmental stage as well as organismic age: the highest susceptibility was observed in L1, whereas the lowest was observed in L4 worms. In adult worms, susceptibility to alkylating agents increased with advanced age, especially to HN2. To examine reproductive effects, L4 worms were exposed to CEES and HN2, and both the offspring and the percentage of unhatched eggs were assessed. Moreover, germline apoptosis was assessed by using ced-1p::GFP (MD701) worms. In contrast to concentrations that elicited low toxicities to L4 worms, CEES and HN2 were highly toxic to germline cells, manifesting as increased germline apoptosis as well as reduced offspring number and percentage of eggs hatched. Again, HN2 exhibited stronger effects than CEES. Compound specificity was also evident in toxicities to dopaminergic neurons-HN2 exposure affected expression of dopamine transporter DAT-1 (strain BY200) at lower concentrations than CEES, suggesting a higher neurotoxic effect. Mechanistically, nicotinamide adenine dinucleotide (NAD+) has been linked to mustard agent toxicities. Therefore, the NAD+-dependent system was investigated in the response to CEES and HN2 treatment. Overall NAD+ levels in worm extracts were revealed to be largely resistant to mustard exposure except for high concentrations, which lowered the NAD+ levels in L4 worms 24 h post-treatment. Interestingly, however, mutant worms lacking components of NAD+-dependent pathways involved in genome maintenance, namely pme-2, parg-2, and sirt-2.1 showed a higher and compound-specific susceptibility, indicating an active role of NAD+ in genotoxic stress response. In conclusion, the present results demonstrate that C. elegans represents an attractive model to study the toxicology of alkylating agents, which supports its use in mechanistic as well as intervention studies with major strength in the possibility to analyze toxicities at different life cycle stages.

Accelerating synergistic effects of preconditioned mesenchymal stem cells with Crocin and dexamethasone in pulmonary epithelial cells injury

Chemical warfare victims suffer from bronchiolitis and chronic pulmonary obstruction caused by sulfur mustard (SM) toxicity. Despite the mesenchymal stem cells capacity to alleviate inflammation, their low survival rate under oxidative stress severely limits their effectiveness. This study aimed to examine how natural (Crocin) and synthetic (Dexamethasone) antioxidants might affect MSC efficacy. MSCs were treated with the optimal doses of Crocin (Cr.), Dexamethasone (Dex.), and their combination. The A549 cells line was pretreated with the optimal dose of the CEES to mimic the lung disease. Then, the affected A549 cells were exposed to the preconditioned MSCs and conditioned media, and then their survival rates were estimated by MTTor2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Annexin-V PI apoptosis test was conducted for MSCs and A549 cells. Reactive Oxygen Species (ROS) assay and Enzyme-linked immunosorbent assay (ELISA) test demonstrated the percentage of production of ROS and the cytokines levels in A549/CEES, respectively. The results revealed significant increases in Cr. + Dex. treated MSCs (P < .01) and A549 cells treated with MSCs-CM/Cr/Dex (P < .01) groups' survival. The apoptosis rate and ROS production were reduced in the MSCs-CM/Cr/Dex. Also, considerable decreases in IL-1β (P < .01) and IL-6 (P < .01) and a significant increase in IL-10 (P < .05) in treated A549/CEES by Cr/Dex and MSCs-CM/Cr/Dex supported the synergistic effects of Crocin and Dexamethasone.

The impact of sulfur mustard on quality of life and mental health in Kurdish survivors in Sweden, thirty years after exposure

BACKGROUND

The Iraqi state used chemical warfare agents (CWAs) like sulfur mustard (SM) in al-Anfal genocide in the present-day Kurdistan Region of Iraq. In addition to somatic injuries, exposure to CWAs causes biopsychosocial complications. We investigated the long-term impact of SM exposure on quality of life (QoL) and depression severity in Kurdish survivors resettled in Sweden.

METHODS

This is a case-control study, where subjects exposed to SM (n = 18, mean age 51.3 years, 50% women) and sex- and age-matched nonexposed subjects (n = 30, mean age 48.7 years, 47% women) of Kurdish residents in Sweden. Data were collected through in-person interviews based on the RAND 36-item Short Form Health Survey to assess QoL and the Montgomery-Åsberg Depression Rating Scale-self assessment (MADRS-S) to investigate the presence and the gravity of depressive symptoms.

RESULTS

The SM-exposed group had a significantly lower QoL than the nonexposed group (p < 0.001). Also, the overall mean MADRS-S scores among the SM-exposed group, corresponding to moderate depression, were higher than the scores of the nonexposed (22 points (p) vs. 9 p, p < .001). Overall, the participants within the exposed group reported worse mental than physical well-being 36p and 32p, respectively. Within the SM-exposed group, there was no gendered-related difference neither in terms of depression severity nor for QoL, but the groups were small.

CONCLUSION

Individuals exposed to SM had worse QoL and a higher level of depressive severity compared with nonexposed individuals three decades after exposure, indicating the importance of increased clinician knowledge, guidelines, and an approach to assess and respond to the exposed groups' biopsychosocial needs. These findings indicate that those exposed to SM might need early identification of mental illnesses and more support to promote QoL.

Sulfur mustard analog 2-chloroethyl ethyl sulfide increases triglycerides by activating DGAT1-dependent biogenesis and inhibiting PGC1ɑ-dependent fat catabolism in immortalized human bronchial epithelial cells

Using sulfur mustard analog 2-chloroethyl ethyl sulfide (CEES), we established an in vitro model by poisoning cultured immortalized human bronchial epithelial cells. Nile Red staining revealed lipids accumulated 24 h after a toxic dose of CEES (0.9 mM). Lipidomics analysis showed most of the increased lipids were triglycerides (TGs), and the increase in TGs was further confirmed using a Triglyceride-Glo™ Assay kit. Protein and mRNA levels of DGAT1, an important TG biogenesis enzyme, were increased following 0.4 mM CEES exposure. Under higher dose CEES (0.9 mM) exposure, protein and mRNA levels of PPARγ coactivator-1ɑ (PGC-1ɑ), a well-known transcription factor that regulates fatty acid oxidation, were decreased. Finally, application with DGAT1 inhibitor A 922500 or PGC1ɑ agonist ZLN005 was able to block the CEES-induced TGs increase. Overall, our dissection of CEES-induced TGs accumulation provides new insight into energy metabolism dysfunction upon vesicant exposure.HIGHLIGHTSIn CEES (0.9 mM)-injured cells:Triglycerides (TGs) were abundant in the accumulated lipids.Expression of DGAT1, not DGAT2, was increased.Expression of PGC1ɑ, not PGC1β, was reduced.DGAT1 inhibitor or PGC1ɑ agonist blocked the CEES-mediated increase in TGs.

Is CEES a good analog of sulfur mustard? Macroscopic aspect, histology, and molecular biology comparisons between sulfur mustard and CEES-induced skin lesions

Sulfur mustard (SM) is a chemical blistering warfare agent affecting multiple organs. SM is an ongoing chemical threat in addition to the accidental risk associated with World War I buried shells. As no specific treatments are available, only symptomatic therapies can be used. To test new medical countermeasures in standard laboratories, analogs such as 2-chloroethyl ethylsulfide (CEES) are currently used, although only a few studies compare its clinical effects with SM. In the present paper, skin lesions induced by SM and CEES are compared in terms of their macroscopic aspects, histology, and molecular biology to evaluate the pertinence of CEES as a SM analog. For this purpose, an in vivo model of CEES vapor exposure, similar to that of SM, is described in this paper. RESULTS: showed similar skin lesions with CEES and SM but with slight differences in the apparition delay and intensity of the lesions. Indeed, SM induced earlier, deeper, and stronger lesions. However, the same healing status was observed at the end of the study period (14 days). In conclusion, CEES appears a relevant analog of SM, leading to similar skin lesions. The CEES vapor exposure model therefore seems suitable for testing new medical countermeasures.