Repeated low-dose exposures to sarin disrupted the homeostasis of phospholipid and sphingolipid metabolism in guinea pig hippocampus

Whole-Transcriptome Analysis of Repeated Low-Level Sarin-Exposed Rat Hippocampus and Identification of Cerna Networks to Investigate the Mechanism of Sarin-Induced Cognitive Impairment

Sarin is a potent organophosphorus nerve agent that causes cognitive dysfunction, but its underlying molecular mechanisms are poorly understood. In this study, a rat model of repeated low-level sarin exposure was established using the subcutaneous injection of 0.4 × LD₅₀ for 21 consecutive days. Sarin-exposed rats showed persistent learning and memory impairment and reduced hippocampal dendritic spine density. A whole-transcriptome analysis was applied to study the mechanism of sarin-induced cognitive impairment, and a total of 1035 differentially expressed mRNA (DEmRNA), including 44 DEmiRNA, 305 DElncRNA, and 412 DEcircRNA, were found in the hippocampus of sarin-treated rats. According to Gene Ontology (GO) annotation, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment, and Protein-Protein Interaction (PPI) analysis, these DERNAs were mainly involved in neuronal synaptic plasticity and were related to the pathogenesis of neurodegenerative diseases. The circRNA/lncRNA-miRNA-mRNA ceRNA network was constructed, in which Circ_Fmn1, miR-741-3p, miR-764-3p, miR-871-3p, KIF1A, PTPN11, SYN1, and MT-CO3 formed one circuit, and Circ_Cacna1c, miR-10b-5p, miR-18a-5p, CACNA1C, PRKCD, and RASGRP1 constituted another circuit. The balance between the two circuits was crucial for maintaining synaptic plasticity and may be the regulatory mechanism by which sarin causes cognitive impairment. Our study reveals the ceRNA regulation mechanism of sarin exposure for the first time and provides new insights into the molecular mechanisms of other organophosphorus toxicants.

A review of chemical warfare agents linked to respiratory and neurological effects experienced in Gulf War Illness

Over 40% of veterans from the Persian Gulf War (GW) (1990-1991) suffer from Gulf War Illness (GWI). Thirty years since the GW, the exposure and mechanism contributing to GWI remain unclear. One possible exposure that has been attributed to GWI are chemical warfare agents (CWAs). While there are treatments for isolated symptoms of GWI, the number of respiratory and cognitive/neurological issues continues to rise with minimum treatment options. This issue does not only affect veterans of the GW, importantly these chronic multisymptom illnesses (CMIs) are also growing amongst veterans who have served in the Afghanistan-Iraq war. What both wars have in common are their regions and inhaled exposures. In this review, we will describe the CWA exposures, such as sarin, cyclosarin, and mustard gas in both wars and discuss the various respiratory and neurocognitive issues experienced by veterans. We will bridge the respiratory and neurological symptoms experienced to the various potential mechanisms described for each CWA provided with the most up-to-date models and hypotheses.

Illuminating the hepatotoxic mechanism of norcantharidin in rats using metabolomics analysis

Background

Norcantharidin (NCTD) has multiple antitumor effects. However, NCTD can induce significant hepatotoxicity and the mechanism of hepatotoxicity is not clear for now.

Objective

This study aimed to explore the hepatotoxicity of NCTD in rat by ultra-performance liquid chromatography (UPLC) quadrupole time-of-flight (Q-TOF)-MS (UPLC/Q-TOF-MS) metabolomics.

Results

Serum biochemical indices including alanine aminotransferase (ALT) and total bilirubin (T-BIL) were significantly increased. Histopathological and ultrastructure results revealed that hepatocytes were damaged. Furthermore, the metabolomics results showed that 11 metabolites in serum and 8 metabolites in liver were differential metabolites for NCTD hepatotoxicity. Four metabolic pathways including the sphingolipid metabolism, purine metabolism, arachidonic acid metabolism, and glycerophospholipid metabolism were the key metabolic pathways related to NCTD hepatotoxicity.

Conclusion

The metabolomics analysis in this study reveal new clues on the hepatotoxicity mechanism of NCTD in rats. These findings have potential applications in the toxicity study of NCTD.

Subacute sarin exposure disrupted the homeostasis of purine and pyrimidine metabolism in guinea pig striatum studied by integrated metabolomic, lipidomic and proteomic analysis

Sarin was used as a chemical weapon due to its high neurotoxicity and mortality. Subacute sarin induced cognitive and behavioral disorder. However, the underlying mechanism is still unclear. Here we offered a multi-omic approach for the analysis of altered metabolites, lipids, and proteins to explore the neurotoxicity of subacute sarin. Guinea pigs were administered between the shoulder blades 16.8 μg/kg of sarin in a volume of 1.0 ml/kg body weight by subcutaneous injection once daily for 14 days. At the end of the final injection, guinea pigs were sacrificed, and striatum were dissected for analysis. A total of 138 different metabolites were identified in the metabolome analysis. Lipids and lipid-like molecules is the largest group (38.41%). For lipidomic analysis, a total of 216 lipids were identified. In proteomic study, over 4300 proteins were identified and quantified. By integrating these enriched components, we demonstrated that the joint pathways disturbed by subacute sarin mainly involving lipid, purine and pyrimidine metabolism in guinea pig striatum. Overall, this study highlights the powerfulness of omics platforms to deepen the understanding of nerve agents caused neurotoxicity.

Association between lipid metabolism and cognitive function in patients with schizophrenia

BACKGROUND

The association between blood lipids and cognitive function in schizophrenia is still controversial. Thus, the present study aimed to verify the association between various lipid parameters and cognitive impairment in schizophrenic patients and potential lipid pathways.

METHODS

A total of 447 adult inpatients with schizophrenia were divided into cognitive normal and cognitive impairment groups based on the Mini-Mental State Examination with a cut-off of 26. The blood lipid parameters were defined as abnormal levels based on the guideline. The liquid chromatography-mass spectrometry method was used to preliminarily explore the potential lipid metabolism pathway associated with cognitive impairment.

RESULTS

There were 368 (82.3%) patients who had cognitive impairment. Herein, apolipoprotein B was positively associated with cognitive function in overall patients and age (≥45 and <45 years) and sex subgroups. After excluding patients with hypertension and diabetes, ApoB was still significantly associated with cognitive function in all the patients. The associations between other lipid parameters, including non-high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol and triglyceride, and cognitive impairment were heterogeneous in age and sex subgroups. In contrast, total cholesterol and apolipoprotein A1 were not significantly associated with cognitive impairment. Metabolomics analysis showed that metabolic pathway mainly involved sphingolipid metabolism. Meanwhile, sphinganine and 3-dehydrosphinganine were positively correlated with lipid parameters and decreased in patients with cognitive impairment as compared to those with normal cognition.

CONCLUSIONS

The present study suggests a positive association between lipids and cognitive function in schizophrenic patients and needs to be further verified by a prospective study.

Markers of Neuroinflammation in the Serum of Prepubertal Children with Fetal Alcohol Spectrum Disorders

BACKGROUND

Fetal Alcohol Spectrum Disorders (FASD) are the manifestation of the damage caused by alcohol consumption during pregnancy. Children with Fetal Alcohol Syndrome (FAS), the extreme FASD manifestation, show both facial dysmorphology and mental retardation. Alcohol consumed during gestational age prejudices brain development by reducing, among others, the synthesis and release of neurotrophic factors and neuroinflammatory markers. Alcohol drinking also induces oxidative stress.

HYPOTHESIS/OBJECTIVE

The present study aimed to investigate the potential association between neurotrophins, neuroinflammation, and oxidative stress in 12 prepubertal male and female FASD children diagnosed as FAS or partial FAS (pFAS).

METHODS

Accordingly, we analyzed, in the serum, the level of BDNF and NGF and the oxidative stress, as Free Oxygen Radicals Test (FORT) and Free Oxygen Radicals Defense (FORD). Moreover, serum levels of inflammatory mediators (IL-1α, IL-2, IL-6, IL-10, IL-12, MCP-1, TGF-β, and TNF-α) involved in neuroinflammatory and oxidative processes have been investigated.

RESULTS

We demonstrated low serum levels of NGF and BDNF in pre-pubertal FASD children with respect to healthy controls. These changes were associated with higher serum presence of TNF- α and IL-1α. Quite interestingly, an elevation in the FORD was also found despite normal FORT levels. Moreover, we found a potentiation of IL-1α, IL-2, IL-10, and IL-1α1 in the analyzed female compared to male children.

CONCLUSION

The present investigation shows an imbalance in the peripheral neuroimmune pathways that could be used in children as early biomarkers of the deficits observed in FASD.

Persistent brainwave disruption and cognitive impairment induced by acute sarin surrogate sub-lethal dose exposure

Warfare neurotoxicants such as sarin, soman or VX, are organophosphorus compounds which irreversibly inhibit cholinesterase. High-dose exposure with nerve agents (NA) is known to produce seizure activity and related brain damage, while less is known about the effects of acute sub-lethal dose exposure. The aim of this study was to characterize behavioral, brain activity and neuroinflammatory modifications at different time points after exposure to 4-nitrophenyl isopropyl methylphosphonate (NIMP), a sarin surrogate. In order to decipher the impacts of sub-lethal exposure, we chose 4 different doses of NIMP each corresponding to a fraction of the median lethal dose (LD₅₀). First, we conducted a behavioral analysis of symptoms during the first hour following NIMP challenge and established a specific scoring scale for the intoxication severity. The intensity of intoxication signs was dose-dependent and proportional to the cholinesterase activity inhibition evaluated in mice brain. The lowest dose (0.3 LD₅₀) did not induce significant behavioral, electrocorticographic (ECoG) nor cholinesterase activity changes. Animals exposed to one of the other doses (0.5, 0.7 and 0.9 LD₅₀) exhibited substantial changes in behavior, significant cholinesterase activity inhibition, and a disruption of brainwave distribution that persisted in a dose-dependent manner. To evaluate long lasting changes, we conducted ECoG recording for 30 days on mice exposed to 0.5 or 0.9 LD₅₀ of NIMP. Mice in both groups showed long-lasting impairment of theta rhythms, and a lack of restoration in hippocampal ChE activity after 1-month post-exposure. In addition, an increase in neuroinflammatory markers (IBA-1, TNF-α, NF-κB) and edema were transiently observed in mice hippocampus. Furthermore, a novel object recognition test showed an alteration of short-term memory in both groups, 1-month post-NIMP intoxication. Our findings identified both transient and long-term ECoG alterations and some long term cognitive impairments following exposure to sub-lethal doses of NIMP. These may further impact morphopathological alterations in the brain.