Early Life Stress and the Onset of Obesity: Proof of MicroRNAs' Involvement Through Modulation of Serotonin and Dopamine Systems' Homeostasis

Risk and Resilience Variants in the Retinoic Acid Metabolic and Developmental Pathways Associated with Risk of FASD Outcomes

Fetal Alcohol Spectrum Disorder (FASD) is a common neurodevelopmental disorder that affects an estimated 2-5% of North Americans. FASD is induced by prenatal alcohol exposure (PAE) during pregnancy and while there is a clear genetic contribution, few genetic factors are currently identified or understood. In this study, using a candidate gene approach, we performed a genetic variant analysis of retinoic acid (RA) metabolic and developmental signaling pathway genes on whole exome sequencing data of 23 FASD-diagnosed individuals. We found risk and resilience alleles in ADH and ALDH genes known to normally be involved in alcohol detoxification at the expense of RA production, causing RA deficiency, following PAE. Risk and resilience variants were also identified in RA-regulated developmental pathway genes, especially in SHH and WNT pathways. Notably, we also identified significant variants in the causative genes of rare neurodevelopmental disorders sharing comorbidities with FASD, including STRA6 (Matthew-Wood), SOX9 (Campomelic Dysplasia), FDG1 (Aarskog), and 22q11.2 deletion syndrome (TBX1). Although this is a small exploratory study, the findings support PAE-induced RA deficiency as a major etiology underlying FASD and suggest risk and resilience variants may be suitable biomarkers to determine the risk of FASD outcomes following PAE.

Gamma-Aminobutyric Acid in Rice Bran Extract Exerts Antistress Effects in Mouse Models with Depressive-Like Behaviors

Various neurotransmitters are involved in regulating stress systems. In this study, we investigated the effects of gamma-aminobutyric acid-rich rice bran extract (GRBe) in mice stressed by forced swimming and tail suspension tests. Four weeks of oral administration of GRBe (500-2000 mg/kg) reduced the levels of dopamine and corticosterone in the blood and brain while increasing serotonin levels. GRBe was involved not only in stress but also in regulating sleep and obesity-related genes. Modern society experiences diverse and tense lives because of urbanization and informatization, which cause excessive stress due to complicated interpersonal relationships, heavy work burden, and fatigue from the organized society. High levels of stress cause psychological instability and disrupt the balance in the autonomic nervous system, which maintains the body's equilibrium, resulting in cardiovascular and cerebrovascular diseases, hormonal imbalances, and sleep disorders. Therefore, our results suggest that GRBe is a useful substance that can relieve tension by ultimately influencing a depressive-like state by lowering the levels of neuronal substances, hormones, and cytokines involved in stress and sleep disorders.

Finding biomarkers of experience in animals

At a time when there is a growing public interest in animal welfare, it is critical to have objective means to assess the way that an animal experiences a situation. Objectivity is critical to ensure appropriate animal welfare outcomes. Existing behavioural, physiological, and neurobiological indicators that are used to assess animal welfare can verify the absence of extremely negative outcomes. But welfare is more than an absence of negative outcomes and an appropriate indicator should reflect the full spectrum of experience of an animal, from negative to positive. In this review, we draw from the knowledge of human biomedical science to propose a list of candidate biological markers (biomarkers) that should reflect the experiential state of non-human animals. The proposed biomarkers can be classified on their main function as endocrine, oxidative stress, non-coding molecular, and thermobiological markers. We also discuss practical challenges that must be addressed before any of these biomarkers can become useful to assess the experience of an animal in real-life.

Oral Delivery of miR-320-3p with Lipidic Aminoglycoside Derivatives at Mid-Lactation Alters miR-320-3p Endogenous Levels in the Gut and Brain of Adult Rats According to Early or Regular Weaning

To investigate if the artificial delivery of microRNAs naturally present in the breastmilk can impact the gut and brain of young rats according to weaning. Animals from a new transgenic rat line expressing the green-fluorescent protein in the endocrine lineage (cholecystokinin expressing cells) received a single oral bolus of miR-320-3p or miR-375-3p embedded in DiOleyl-Succinyl-Paromomycin (DOSP) on D-12. The pups were weaned early (D-15), or regularly (D-30). The expression of relevant miRNA, mRNAs, chromatin complexes, and duodenal cell density were assessed at 8 h post-inoculation and on D-45. The miR-320-3p/DOSP induced immediate effects on H3K4me3 chromatin complexes with polr3d promoter (p < 0.05). On regular weaning, on D-45, miR-320-3p and 375-3p were found to be downregulated in the stomach and upregulated in the hypothalamus (p < 0.001), whereas miR-320-3p was upregulated in the duodenum. After early weaning, miR-320-3p and miR-375-3p were downregulated in the stomach and the duodenum, but upregulated in the hypothalamus and the hippocampus. Combination of miR-320-3p/DOSP with early weaning enhanced miR-320-3p and chromogranin A expression in the duodenum. In the female brain stem, miR-320-3p, miR-504, and miR-16-5p levels were all upregulated. Investigating the oral miRNA-320-3p loads in the duodenal cell lineage paved the way for designing new therapeutics to avoid unexpected long-term impacts on the brain.

The early-life stress induced by oxytocin inhibition in p53 knockout mouse dams increases adulthood tumorigenesis in first and second generations

BACKGROUND

Early-life stress due to poor parental care has been suggested to increase cancer risk, though, so far, no experimental evidence established a link between defective parental behavior and spontaneous tumorigenesis in progeny. Essential maternal behavior is regulated, in particular, by the oxytocin (OT) hormonal circuit, which in turn responds to stimuli from the offspring and impinges on the central nervous systems.

METHODS

By providing L-368,899 OT receptor (OTR) inhibitor to lactating mothers, we set up a model of defective maternal care in p53 knockout mice.

RESULTS

The progeny of these dams showed, later in life, higher cortisol levels, shortened life span and increased tumorigenic potential of bone marrow cells (BMC). Notably, these phenotypes were transmitted to the following generation.

CONCLUSIONS

Therefore, the inhibition of OT function in mothers is a novel paradigm of early-life stress that is inherited across generations and increases cancer risk in tumor-prone mice.

Limitations of the protective measure theory in explaining the role of childhood sexual abuse in eating disorders, addictions, and obesity: an updated model with emphasis on biological embedding

In addition to its immediate negative consequences, childhood sexual abuse is associated with lifelong deleterious mental and physical health outcomes. This review employs a biopsychosocial perspective to better understand pathways from childhood sexual abuse to eating disorders, food and drug addictions, and obesity across the life course. Guided by an updated conceptual model, this review delineates how the biological embedding of childhood sexual abuse triggers a cascade of interrelated conditions that often result in failed attempts at weight suppression and eventually obesity. Such biological embedding involves pathways such as inflammation, allostatic load, reward sensitivity, activation of the hypothalamic-pituitary-adrenal axis, epigenetics, and structural and functional changes in the brain. These pathways are in turn theorized to lead to food addiction, substance use disorder, and eating disorders-each with potential pathways toward obesity over time. Predisposing factors to childhood sexual abuse including gender, culture, and age are discussed. This model calls into question the longstanding "protective measure" theory that purports individuals exposed to sexual abuse will deliberately or subconsciously gain weight in attempt to prevent future victimization. A more comprehensive understanding of the mechanisms by which childhood sexual abuse becomes biologically embedded may help clinicians and survivors normalize and/or address disordered eating and weight-related outcomes, as well as identify intervention strategies.Level of evidence: Level V: opinions of respected authorities, based on descriptive studies, narrative reviews, clinical experience, or reports of expert committees.

Evaluation of miRNA as Biomarkers of Emotional Valence in Pigs

Simple Summary

It is widely recognized that the assessment of animal welfare should include measures of positive emotional (affective) state. Existing behavioral and physiological indicators of a positive affective state frequently lack sensitivity, objectivity or are unsuitable in a production environment. Therefore, there is a need to develop new approaches to accurately and objectively measure a positive emotional state in animals, including novel molecular markers such a miRNA. These biomarkers must be measurable in the peripheral circulation and provide an accurate account of the physiological and molecular activity in regions of the brain associated with emotional processing. Further, such markers require validation against established behavioral and physiological indices. Here we investigated the efficacy of circulating miRNA as biomarkers of emotional state in the pig.

Abstract

The ability to assess the welfare of animals is dependent on our ability to accurately determine their emotional (affective) state, with particular emphasis being placed on the identification of positive emotions. The challenge remains that current physiological and behavioral indices are either unable to distinguish between positive and negative emotional states, or they are simply not suitable for a production environment. Therefore, the development of novel measures of animal emotion is a necessity. Here we investigated the efficacy of microRNA (miRNA) in the brain and blood as biomarkers of emotional state in the pig. Female Large White × Landrace pigs (n = 24) were selected at weaning and trained to perform a judgment bias test (JBT), before being exposed for 5 weeks to either enriched (n = 12) or barren housing (n = 12) conditions. Pigs were tested on the JBT once prior to treatment, and immediately following treatment. MiRNA and neurotransmitters were analyzed in blood and brain tissue after euthanasia. Treatment had no effect on the outcomes of the JBT. There was also no effect of treatment on miRNA expression in blood or the brain (FDR p > 0.05). However, pigs exposed to enriched housing had elevated dopamine within the striatum compared to pigs in barren housing (p = 0.02). The results imply that either (a) miRNAs are not likely to be valid biomarkers of a positive affective state, at least under the type of conditions employed in this study, or (b) that the study design used to modify affective state was not able to create differential affective states, and therefore establish the validity of miRNA as biomarkers.

Association between different dimensions of childhood traumatization and plasma micro-RNA levels in a clinical psychiatric sample

As an epigenetic regulator micro-RNAs (miRNAs) have gained increasing attention in biomarker research for diseases. Many studies point towards an involvement of miRNAs in neuropsychiatric disorders such as Alzheimer's Disease, schizophrenia or depression. In a recent study we identified a possible relationship between childhood traumatization and miRNAs associated with Alzheimer's Disease in the general population as well as in a small psychiatric clinical sample. In this study we aimed to confirm this biological link in an independent psychiatric clinical sample (N = 104) and to also explore the impact of different childhood trauma dimensions (sum score, abuse dimension and neglect dimension). Analyses revealed their different impact on disease in the combined sample (N = 154; N = 50 from the recent study). We could confirm associations for all of the four recently identified miRNAs in the replication sample (N = 104) on a suggested significance level of p < 0.08 (two with p < 0.05). In the combined sample (N = 154) fifteen miRNAs were significantly associated with the childhood trauma sum score after correction for multiple testing. Most of them showed recently significant associations for Alzheimer's Disease. For the subscores of abuse and neglect only one miRNA was identified in addition, associated with childhood neglect. Bioinformatics analysis identified significant brain-related pathways regulated by the respective miRNAs. At the time of publication our study is the largest study of the association between childhood trauma and miRNAs in a clinical psychiatric sample. The confirmation of our previous results supports the relevance of the association between childhood traumatization and Alzheimer's Disease through miRNA regulation of brain-related pathways.

Protective effects of antidepressant citalopram against abnormal APP processing and amyloid beta-induced mitochondrial dynamics, biogenesis, mitophagy and synaptic toxicities in Alzheimer's disease

The purpose of this study is to study the neuroprotective role of selective serotonin reuptake inhibitor (SSRI), citalopram, against Alzheimer's disease (AD). Multiple SSRIs, including citalopram, are reported to treat patients with depression, anxiety and AD. However, their protective cellular mechanisms have not been studied completely. In the current study, we investigated the protective role of citalopram against impaired mitochondrial dynamics, defective mitochondrial biogenesis, defective mitophagy and synaptic dysfunction in immortalized mouse primary hippocampal cells (HT22) expressing mutant APP (SWI/IND) mutations. Using quantitative RT-PCR, immunoblotting, biochemical methods and transmission electron microscopy methods, we assessed mutant full-length APP/C-terminal fragments and Aβ levels and mRNA and protein levels of mitochondrial dynamics, biogenesis, mitophagy and synaptic genes in mAPP-HT22 cells and mAPP-HT22 cells treated with citalopram. Increased levels of mRNA levels of mitochondrial fission genes, decreased levels of fusion biogenesis, autophagy, mitophagy and synaptic genes were found in mAPP-HT22 cells relative to WT-HT22 cells. However, mAPP-HT22 cells treated with citalopram compared to mAPP-HT22 cells revealed reduced levels of the mitochondrial fission genes, increased fusion, biogenesis, autophagy, mitophagy and synaptic genes. Our protein data agree with mRNA levels. Transmission electron microscopy revealed significantly increased mitochondrial numbers and reduced mitochondrial length in mAPP-HT22 cells; these were reversed in citalopram-treated mAPP-HT22 cells. Cell survival rates were increased in citalopram-treated mAPP-HT22 relative to citalopram-untreated mAPP-HT22. Further, mAPP and C-terminal fragments werealso reduced in citalopram-treated cells. These findings suggest that citalopram reduces mutant APP and Aβ and mitochondrial toxicities and may have a protective role of mutant APP and Aβ-induced injuries in patients with depression, anxiety and AD.

Selective serotonin reuptake inhibitor citalopram ameliorates cognitive decline and protects against amyloid beta-induced mitochondrial dynamics, biogenesis, autophagy, mitophagy and synaptic toxicities in a mouse model of Alzheimer's disease

In the current study, we investigated the protective role of citalopram against cognitive decline, impaired mitochondrial dynamics, defective mitochondrial biogenesis, defective autophagy, mitophagy and synaptic dysfunction in APP transgenic mouse model of Alzheimer's disease (ad). We treated 12-month-old wild-type (WT) and age-matched transgenic APP mice with citalopram for 2 months. Using Morris Water Maze and rotarod tests, quantitative RT-PCR, immunoblotting, biochemical methods and transmission electron microscopy methods, we assessed cognitive behavior, RNA and protein levels of mitochondrial dynamics, biogenesis, autophagy, mitophagy, synaptic, ad-related and neurogenesis genes in wild-type and APP mice treated and untreated with citalopram. Citalopram-treated APP mice relative to citalopram-untreated APP mice exhibited improved cognitive behavior. Increased levels of mRNA associated with mitochondrial fission and ad-related genes; decreased levels of fusion, biogenesis, autophagy, mitophagy, synaptic and neurogenesis genes were found in APP mice relative to WT mice. However, APP mice treated with citalopram compared to citalopram-untreated APP mice revealed reduced levels of the mitochondrial fission and ad-related genes and increased fusion, biogenesis, autophagy, mitophagy, synaptic and neurogenesis genes. Our protein data agree with the mRNA levels. Transmission electron microscopy revealed significantly increased mitochondrial numbers and reduced mitochondrial length in APP mice; these were reversed in citalopram-treated APP mice. Further, Golgi-cox staining analysis revealed reduced dendritic spines in APP mice relative to WT mice. However, citalopram-treated APP mice showed significantly increased dendritic spines, indicating that citalopram enhances spine density, synaptic activity and improved cognitive function in APP mice. These findings suggest that citalopram reduces cognitive decline, Aβ levels and mitochondrial and synaptic toxicities and may have a strong protective role against mutant APP and Aβ-induced injuries in patients with depression, anxiety and ad.

Regulation of the gut barrier by carbohydrates from diet - Underlying mechanisms and possible clinical implications

The gut barrier has been recognized as being of relevance in the pathogenesis of multiple different diseases ranging from inflammatory bowel disease, irritable bowel syndrome, inflammatory joint disease, fatty liver disease, and cardiometabolic disorders. The regulation of the gut barrier is, however, poorly understood. Especially, the role of food components such as sugars and complex carbohydrates has been discussed controversially in this respect. More recently, the intestinal microbiota has been proposed as an important regulator of the gut barrier. Whether the microbiota affects the barrier by its own, or whether food components such as carbohydrates mediate their effects through alterations of the microbiota composition or its metabolites, is still not clear. In this review, we will summarize the current knowledge on this topic derived from both animal and human studies and discuss data for possible clinical impact.