Transcriptomic analysis of glutamate-induced HT22 neurotoxicity as a model for screening anti-Alzheimer's drugs.

Glutamate-induced neurotoxicity in the HT22 mouse hippocampal neuronal cell line has been recognized as a valuable cell model for the study of neurotoxicity associated with neurodegenerative diseases including Alzheimer's disease (AD). However, the relevance of this cell model for AD pathogenesis and preclinical drug screening remains to be more elucidated. While there is increasing use of this cell model in a number of studies, relatively little is known about its underlying molecular signatures in relation to AD. Here, our RNA sequencing study provides the first transcriptomic and network analyses of HT22 cells following glutamate exposure. Several differentially expressed genes (DEGs) and their relationships specific to AD were identified. Additionally, the usefulness of this cell model as a drug screening system was assessed by determining the expression of those AD-associated DEGs in response to two medicinal plant extracts, Acanthus ebracteatus and Streblus asper, that have been previously shown to be protective in this cell model. In summary, the present study reports newly identified AD-specific molecular signatures in glutamate-injured HT22 cells, suggesting that this cell can be a valuable model system for the screening and evaluation of new anti-AD agents, particularly from natural products.

Fimbristylis ovata and Artemisia vulgaris extracts inhibited AGE-mediated RAGE expression, ROS generation, and inflammation in THP-1 cells.

Advanced glycation end products (AGEs) can induce inflammatory signaling pathways through the receptor for AGEs (RAGE). Targeting RAGE could be a therapeutic strategy for treating chronic inflammation mediated by the AGE-RAGE axis. This study aimed to investigate the effects of Fimbristylis ovata and Artemisia vulgaris extracts on AGE-RAGE signaling and AGE-mediated oxidative stress and inflammation in THP-1 cells. F. ovata and A. vulgaris were extracted by a Soxhlet extraction, and antioxidant capacity was evaluated using DPPH and ABTS assays. The human monocytic cell line THP-1 was treated with AGE (600 µg/ml) with and without F. ovata and A. vulgaris extracts (100 µg/ml). The mitochondria-targeting antioxidant MitoQ (2 µg/ml) was used as a positive control. Cell viability, ROS generation, RAGE, AGE-RAGE signaling pathway components, and inflammatory cytokine levels were analyzed. F. ovata and A. vulgaris extracts showed antioxidative effects in non-cell-based assays. Treatment of THP-1 cells with AGE significantly increased the protein levels of RAGE and significantly increased the mRNA expression of cytokines, including TNF-α, IL-1ß, and IL-6. AGEs induced the generation of ROS and levels of signaling molecules downstream of RAGE, including phosphorylated and total Erk1/2, JNK, and p38 MAPK, although not significantly. F. ovata and A. vulgaris extracts significantly decreased the protein levels of RAGE and significantly decreased the mRNA levels of cytokines. In conclusion, this study revealed that F. ovata and A. vulgaris extracts exert anti-inflammatory effects through the AGE-RAGE axis. However, details on this anti-inflammatory effect through AGE-RAGE signaling should be further investigated. Supplementary Information: The online version contains supplementary material available at 10.1007/s43188-021-00114-0.

Prenatal exposure to bisphenol A alters the transcriptome-interactome profiles of genes associated with Alzheimer's disease in the offspring hippocampus.

Our recent study revealed that prenatal exposure to bisphenol A (BPA) disrupted the transcriptome profiles of genes in the offspring hippocampus. In addition to genes linked to autism, several genes associated with Alzheimer's disease (AD) were found to be differentially expressed, although the association between BPA-responsive genes and AD-related genes has not been thoroughly investigated. Here, we demonstrated that in utero BPA exposure also disrupted the transcriptome profiles of genes associated with neuroinflammation and AD in the hippocampus. The level of NF-κB protein and its AD-related target gene Bace1 were significantly increased in the offspring hippocampus in a sex-dependent manner. Quantitative RT-PCR analysis also showed an increase in the expression of Tnf gene. Moreover, the reanalysis of transcriptome profiling data from several previously published BPA studies consistently showed that BPA-responsive genes were significantly associated with top AD candidate genes. The findings from this study suggest that maternal BPA exposure may increase AD risk in offspring by dysregulating genes associated with AD neuropathology and inflammation and reveal a possible relationship between AD and autism, which are linked to the same environmental factor. Sex-specific effects of prenatal BPA exposure on the susceptibility of AD deserve further investigation.

A Mitochondrial Specific Antioxidant Reverses Metabolic Dysfunction and Fatty Liver Induced by Maternal Cigarette Smoke in Mice.

Maternal smoking leads to glucose and lipid metabolic disorders and hepatic damage in the offspring, potentially due to mitochondrial oxidative stress. Mitoquinone mesylate (MitoQ) is a mitochondrial targeted antioxidant with high bioavailability. This study aimed to examine the impact of maternal cigarette smoke exposure (SE) on offspring's metabolic profile and hepatic damage, and whether maternal MitoQ supplementation during gestation can affect these changes. Female Balb/c mice (eight weeks) were either exposed to air or SE for six weeks prior to mating and throughout gestation and lactation. A subset of the SE dams were supplied with MitoQ in the drinking water (500 µmol/L) during gestation and lactation. Intraperitoneal glucose tolerance test was performed in the male offspring at 12 weeks and the livers and plasma were collected at 13 weeks. Maternal SE induced glucose intolerance, hepatic steatosis, mitochondrial oxidative stress and related damage in the adult offspring. Maternal MitoQ supplementation reduced hepatic mitochondrial oxidative stress and improved markers of mitophagy and mitochondrial biogenesis. This may restore hepatic mitochondrial health and was associated with an amelioration of glucose intolerance, hepatic steatosis and pathological changes induced by maternal SE. MitoQ supplementation may potentially prevent metabolic dysfunction and hepatic pathology induced by intrauterine SE.

MitoQ supplementation prevent long-term impact of maternal smoking on renal development, oxidative stress and mitochondrial density in male mice offspring.

To investigate the effect of maternal MitoQ treatment on renal disorders caused by maternal cigarette smoke exposure (SE). We have demonstrated that maternal SE during pregnancy increases the risk of developing chronic kidney disease (CKD) in adult offspring. Mitochondrial oxidative damage contributes to the adverse effects of maternal smoking on renal disorders. MitoQ is a mitochondria-targeted antioxidant that has been shown to protect against oxidative damage-related pathologies in many diseases. Female Balb/c mice (8 weeks) were divided into Sham (exposed to air), SE (exposed to cigarette smoke) and SEMQ (exposed to cigarette smoke with MitoQ supplemented from mating) groups. Kidneys from the mothers were collected when the pups weaned and those from the offspring were collected at 13 weeks. Maternal MitoQ supplementation during gestation and lactation significantly reversed the adverse impact of maternal SE on offspring's body weight, kidney mass and renal pathology. MitoQ administration also significantly reversed the impact of SE on the renal cellular mitochondrial density and renal total reactive oxygen species in both the mothers and their offspring in adulthood. Our results suggested that MitoQ supplementation can mitigate the adverse impact of maternal SE on offspring's renal pathology, renal oxidative stress and mitochondrial density in mice offspring.

Maternal E-Cigarette Exposure in Mice Alters DNA Methylation and Lung Cytokine Expression in Offspring.

E-cigarette usage is increasing, especially among the young, with both the general population and physicians perceiving them as a safe alternative to tobacco smoking. Worryingly, e-cigarettes are commonly used by pregnant women. As nicotine is known to adversely affect children in utero, we hypothesized that nicotine delivered via e-cigarettes would negatively affect lung development. To test this, we developed a mouse model of maternal e-vapor (nicotine and nicotine-free) exposure and investigated the impact on the growth and lung inflammation in both offspring and mothers. Female Balb/c mice were exposed to e-fluid vapor containing nicotine (18 mg/ml nicotine E-cigarette [E-cig18], equivalent to two cigarettes per treatment, twice daily,) or nicotine free (E-cig0 mg/ml) from 6 weeks before mating until pups weaned. Male offspring were studied at Postnatal Day (P) 1, P20, and at 13 weeks. The mothers were studied when the pups weaned. In the mothers' lungs, e-cigarette exposure with and without nicotine increased the proinflammatory cytokines IL-1ß, IL-6, and TNF-α. In adult offspring, TNF-α protein levels were increased in both E-cig18 and E-cig0 groups, whereas IL-1ß was suppressed. This was accompanied by global changes in DNA methylation. In this study, we found that e-cigarette exposure during pregnancy adversely affected maternal and offspring lung health. As this occurred with both nicotine-free and nicotine-containing e-vapor, the effects are likely due to by-products of vaporization rather than nicotine.