Maternal Immune Activation with H1N1 or Toxoplasma gondii Antigens Induces Behavioral Impairments Associated with Mood Disorders in Rodents

Therapeutic potential of Garcinia kola against experimental toxoplasmosis in rats

Cerebral toxoplasmosis, the most common opportunistic infection in immunocompromised individuals, is increasingly reported in immunocompetent individuals due to mutant strains of Toxoplasma gondii, which, furthermore, are reported to be resistant to available treatments. We assessed the therapeutic potential of Garcinia kola, a medicinal plant reported to have antiplasmodial and neuroprotective properties, against experimental toxoplasmosis in rats. Severe toxoplasmosis was induced in male Wistar rats (156.7 ± 4.1 g) by injecting them with 10 million tachyzoites in suspension in 500 µl of saline (intraperitoneal), and exclusive feeding with a low-protein diet [7% protein (weight by weight)]. Then, animals were treated with hexane, dichloromethane, and ethyl acetate fractions of Garcinia kola. Footprints were analysed and open-field and elevated plus maze ethological tests were performed when symptoms of severe disease were observed in the infected controls. After sacrifice, blood samples were processed for Giemsa staining, organs were processed for haematoxylin and eosin staining, and brains were processed for Nissl staining and cell counting. Compared with non-infected animals, the infected control animals had significantly lower body weights (30.27%↓, P = 0.001), higher body temperatures (P = 0.033) during the sacrifice, together with signs of cognitive impairment and neurologic deficits such as lower open-field arena centre entries (P < 0.001), elevated plus maze open-arm time (P = 0.029) and decreased stride lengths and step widths (P < 0.001), as well as neuronal loss in various brain areas. The ethyl acetate fraction of Garcinia kola prevented or mitigated most of these signs. Our data suggest that the ethyl acetate fraction of Garcinia kola has therapeutic potential against cerebral toxoplasmosis.

Maternal immune activation as an epidemiological risk factor for neurodevelopmental disorders: Considerations of timing, severity, individual differences, and sex in human and rodent studies

Epidemiological evidence suggests that one's risk of being diagnosed with a neurodevelopmental disorder (NDD)-such as autism, ADHD, or schizophrenia-increases significantly if their mother had a viral or bacterial infection during the first or second trimester of pregnancy. Despite this well-known data, little is known about how developing neural systems are perturbed by events such as early-life immune activation. One theory is that the maternal immune response disrupts neural processes important for typical fetal and postnatal development, which can subsequently result in specific and overlapping behavioral phenotypes in offspring, characteristic of NDDs. As such, rodent models of maternal immune activation (MIA) have been useful in elucidating neural mechanisms that may become dysregulated by MIA. This review will start with an up-to-date and in-depth, critical summary of epidemiological data in humans, examining the association between different types of MIA and NDD outcomes in offspring. Thereafter, we will summarize common rodent models of MIA and discuss their relevance to the human epidemiological data. Finally, we will highlight other factors that may interact with or impact MIA and its associated risk for NDDs, and emphasize the importance for researchers to consider these when designing future human and rodent studies. These points to consider include: the sex of the offspring, the developmental timing of the immune challenge, and other factors that may contribute to individual variability in neural and behavioral responses to MIA, such as genetics, parental age, the gut microbiome, prenatal stress, and placental buffering.

Effect of Season of Birth on Hippocampus Volume in a Transdiagnostic Sample of Patients With Depression and Schizophrenia

Psychiatric disorders share an excess of seasonal birth in winter and spring, suggesting an increase of neurodevelopmental risks. Evidence suggests season of birth can serve as a proxy of harmful environmental factors. Given that prenatal exposure of these factors may trigger pathologic processes in the neurodevelopment, they may consequently lead to brain volume alterations. Here we tested the effects of season of birth on gray matter volume in a transdiagnostic sample of patients with schizophrenia and depression compared to healthy controls (n = 192). We found a significant effect of season of birth on gray matter volume with reduced right hippocampal volume in summer-born compared to winter-born patients with depression. In addition, the volume of the right hippocampus was reduced independent from season of birth in schizophrenia. Our results support the potential impact of season of birth on hippocampal volume in depression.

Consequences of Viral Infection and Cytokine Production During Pregnancy on Brain Development in Offspring

Infections during pregnancy can seriously damage fetal neurodevelopment by aberrantly activating the maternal immune system, directly impacting fetal neural cells. Increasing evidence suggests that these adverse impacts involve alterations in neural stem cell biology with long-term consequences for offspring, including neurodevelopmental disorders such as autism spectrum disorder, schizophrenia, and cognitive impairment. Here we review how maternal infection with viruses such as Influenza A, Cytomegalovirus, and Zika during pregnancy can affect the brain development of offspring by promoting the release of maternal pro-inflammatory cytokines, triggering neuroinflammation of the fetal brain, and/or directly infecting fetal neural cells. In addition, we review insights into how these infections impact human brain development from studies with animal models and brain organoids. Finally, we discuss how maternal infection with SARS-CoV-2 may have consequences for neurodevelopment of the offspring.

Maternal inflammation and its ramifications on fetal neurodevelopment

Exposure to heightened inflammation in pregnancy caused by infections or other inflammatory insults has been associated with the onset of neurodevelopmental and psychiatric disorders in children. Rodent models have provided unique insights into how this maternal immune activation (MIA) disrupts brain development. Here, we discuss the key immune factors involved, highlight recent advances in determining the molecular and cellular pathways of MIA, and review how the maternal immune system affects fetal development. We also examine the roles of microbiomes in shaping maternal immune function and the development of autism-like phenotypes. A comprehensive understanding of the gut bacteria-immune-neuro interaction in MIA is essential for developing diagnostic and therapeutic measures for high-risk pregnant women and identifying targets for treating inflammation-induced neurodevelopmental disorders.

Ginsenoside Rh2 reduces depression in offspring of mice with maternal toxoplasma infection during pregnancy by inhibiting microglial activation via the HMGB1/TLR4/NF-κB signaling pathway

Background

Maternal Toxoplasma gondii (T. gondii) infection during pregnancy has been associated with various mental illnesses in the offspring. Ginsenoside Rh2 (GRh2) is a major bioactive compound obtained from ginseng that has an anti-T. gondii effect and attenuates microglial activation through toll-like receptor 4 (TLR4)/nuclear factor-kappa B (NF-κB) signaling pathway. GRh2 also alleviated tumor-associated or lipopolysaccharide-induced depression. However, the effects and potential mechanisms of GRh2 on depression-like behavior in mouse offspring caused by maternal T. gondii infection during pregnancy have not been investigated.

Methods

We examined GRh2 effects on the depression-like behavior in mouse offspring, caused by maternal T. gondii infection during pregnancy, by measuring depression-like behaviors and assaying parameters at the neuronal and molecular level.

Results

We showed that GRh2 significantly improved behavioral measures: sucrose consumption, forced swim time and tail suspended immobility time of their offspring. These corresponded with increased tissue concentrations of 5-hydroxytryptamine and dopamine, and attenuated indoleamine 2,3-dioxygenase or enhanced tyrosine hydroxylase expression in the prefrontal cortex. GRh2 ameliorated neuronal damage in the prefrontal cortex. Molecular docking results revealed that GRh2 binds strongly to both TLR4 and high mobility group box 1 (HMGB1).

Conclusion

This study demonstrated that GRh2 ameliorated the depression-like behavior in mouse offspring of maternal T. gondii infection during pregnancy by attenuating the excessive activation of microglia and neuroinflammation through the HMGB1/TLR4/NF-κB signaling pathway. It suggests that GRh2 could be considered a potential therapy in preventing and treating psychiatric disorders in the offspring mice of mothers with prenatal exposure to T. gondii infection.

Anxiolytic-like and antidepressant-like effects of ethanol extract of Terminalia chebula in mice

Terminalia chebula (T.chebula) fruit is referred as "King of Medicines" in Tibet and is listed as a key plant in "Ayurvedic Materia Medica" due to its diverse pharmacological activity. The present study was aimed to investigate the comorbid antidepressant-like and anxiolytic-like effects of ethanol extract from T.chebula fruit using experimental behavioral tests in mice. In addition, the study explored the effects of extract on monoamine oxidase -A (MAO-A) levels in mouse brain. Two doses of the T.chebula extract (100 or 200 mg/kg, p.o.) were treated continuously for fifteen days to mice. Regarding antidepressant-like effects, the treatment of T.chebula extract at both dose (100 or 200 mg/kg, p.o.) levels resulted with significant (p < 0.001) reduction in duration of immobility time and increase in swimming time as compared to control group in forced swimming test. Moreover, both doses declined the duration of immobility time in the tail suspension test and increased the number of crossing in the center area using open-field test. Additionally, the dose 200 mg/kg treatment showed a significant reduction (p < 0.05) in MAO-A activity in mouse brain. For anxiolytic activity, both doses significantly (p < 0.001) improved the time spent in open arm and the number of head dips in elevated plus maze test. The higher duration of time spent in light chamber and higher number of crossing between the light and dark chambers by extract treatment in light-dark box test also supported the anxiolytic behavior. The obtained results supported the antidepressant-like and anxiolytic-like effects of ethanol extract of T.chebula in mice.