The role of glial autophagy in Alzheimer's disease.

Although Alzheimer's disease is the most pervasive neurodegenerative disorder, the mechanism underlying its development is still not precisely understood. Available data indicate that pathophysiology of this disease may involve impaired autophagy in glial cells. The dysfunction is manifested as reduced ability of astrocytes and microglia to clear abnormal protein aggregates. Consequently, excessive accumulation of amyloid beta plaques and neurofibrillary tangles activates microglia and astrocytes leading to decreased number of mature myelinated oligodendrocytes and death of neurons. These pathologic effects of autophagy dysfunction can be rescued by pharmacological activation of autophagy. Therefore, a deeper understanding of the molecular mechanisms involved in autophagy dysfunction in glial cells in Alzheimer's disease may lead to the development of new therapeutic strategies. However, such strategies need to take into consideration differences in regulation of autophagy in different types of neuroglia.

Bilateral subdiaphragmatic vagotomy modulates the peripheral met­enkephalin and striatal monoamine responses to peripheral inflammation in rat.

In the central nervous system, long­term effects of a vagotomy include disturbance of monoaminergic activity of the limbic system. Since low vagal activity is observed in major depression and autism spectrum disorder, the study aimed to determine whether animals fully recovered after subdiaphragmatic vagotomy demonstrates neurochemical indicators of altered well­being and social component of sickness behavior. Bilateral vagotomy or sham surgery was performed in adult rats. After one month of recovery, rats were challenged with lipopolysaccharide or vehicle to determine the role of central signaling upon sickness. Striatal monoamines and met­enkephalin concentrations were evaluated using HPLC and RIA methods. We also defined a concentration of immune­derived plasma met­enkephalin to establish a long­term effect of vagotomy on peripheral analgesic mechanisms. The data indicate that 30 days after vagotomy procedure, striatal dopaminergic, serotoninergic, and enkephalinergic neurochemistry was altered, both under physiological and inflammatory conditions. Vagotomy prevented inflammation­induced increases of plasma met­enkephalin - an opioid analgesic. Our data suggest that in a long perspective, vagotomized rats may be more sensitive to pain and social stimuli during peripheral inflammation.

Hypothalamic Neurochemical Changes in Long-Term Recovered Bilateral Subdiaphragmatic Vagotomized Rats.

Background: Vagus nerve is one of the crucial routes in communication between the immune and central nervous systems. The impaired vagal nerve function may intensify peripheral inflammatory processes. This effect subsides along with prolonged recovery after permanent nerve injury. One of the results of such compensation is a normalized plasma concentration of stress hormone corticosterone - a marker of hypothalamic-pituitary-adrenal (HPA) axis activity. In this work, we strive to explain this corticosterone normalization by studying the mechanisms responsible for compensation-related neurochemical alterations in the hypothalamus. Materials and Methods: Using microarrays and high performance liquid chromatography (HPLC), we measured genome-wide gene expression and major amino acid neurotransmitters content in the hypothalamus of bilaterally vagotomized rats, 1 month after surgery. Results: Our results show that, in the long term, vagotomy affects hypothalamic amino acids concentration but not mRNA expression of tested genes. Discussion: We propose an alternative pathway of immune to CNS communication after vagotomy, leading to activation of the HPA axis, by influencing central amino acids and subsequent monoaminergic neurotransmission.

Blastomere removal affects homeostatic control leading to obesity in male mice.

Preimplantation embryos are particularly vulnerable to environmental perturbations, including those related to assisted reproductive technologies. Invasive embryo manipulations, such as blastomere biopsy, are applied worldwide in clinical settings for preimplantation genetic testing. Mouse models have previously shown that blastomere biopsy may be associated with altered phenotypes in adult offspring. The aim of the present study was to investigate the specific contribution of blastomere removal to the physiological, behavioral, and molecular regulators of energy homeostasis, as compared to sham manipulation (re-introducing the blastomere into the embryo after its removal) and in vitro culture. Mice derived from 8-cell embryos subjected to blastomere removal displayed: (i) higher body weight and adiposity, (ii) increased food intake and sucrose preference, (iii) decreased time of immobility in the tail suspension test, and (iv) resistance to weight loss after social isolation or following 3 days of physical exercise - compared to mice derived from sham biopsy or from in vitro-cultured embryos. Mice generated after blastomere removal also had increased circulating leptin and leptin gene expression in adipose tissue, as well as increased ghrelin receptor gene expression in the hypothalamus, compared to control mice. The effects of blastomere biopsy on offspring phenotype were sexually dimorphic, with females not being affected. These results indicate that blastomere deprivation, rather than other perturbations of the blastomere biopsy procedure, programs male embryos to develop physiological, behavioral, and molecular dysregulation of energy homeostasis, leading to postnatal obesity.

Pregnancy at Advanced Maternal Age Affects Behavior and Hippocampal Gene Expression in Mouse Offspring.

There is growing evidence that advanced maternal age is a risk factor for neurological and neuropsychiatric disorders in offspring. However, it remains unclear whether the altered brain programming induced by advanced maternal age is mediated by pre- or postnatal factors. Here, a mouse model was used to investigate whether pregnancy at advanced age may provoke behavioral and brain gene expression changes in offspring. Swiss Albino mice conceived by 3-month-old males and either 15-18-month-old (n = 11) or 3-month-old control females (n = 5), were delivered by cesarean section, fostered after birth by 3-month-old dams and subjected to a battery of behavioral tests. Furthermore, genome-wide mRNA expression was analyzed in the hippocampi of 4-month-old males offspring using microarrays. Offspring conceived by old mothers exhibited increased ultrasound vocalization activity during separation from the foster mother, increased anxiety-like behaviors in adult life, and altered patterns of hippocampal gene expression, compared to controls. These effects were not reversed by the postnatal maternal care provided by the young foster mothers, suggesting that the altered brain programming is already established at birth, consistent with prenatal effects related to maternal aging.