Cytokine Receptors in the Brain

Adolescent neuroimmune function and its interaction with alcohol

Adolescence is an evolutionarily conserved developmental period associated with behavioral change, including increased risk-taking and alcohol use. Experimentation with alcohol typically begins in adolescence and transitions to binge-like patterns of consumption. Alcohol exposure during adolescence can alter normative changes in brain structure and function. Understanding mechanisms by which ethanol impacts neurodevelopmental processes is important for preventing and ameliorating the deleterious consequences of adolescent alcohol abuse. This review focuses on the neuroimmune system as a key contributor to ethanol-induced changes in adolescent brain and behavior. After brief review of neuroimmune system development, acute and chronic effects of ethanol on adolescent neuroimmune functioning are addressed. Comparisons between stress/immunological challenges and ethanol on adolescent neuroimmunity are reviewed, as cross-sensitization is relevant during adolescence. The mechanisms by which ethanol alters neuroimmune functioning are then discussed, as they may portend development of neuropathological consequences and thus increase vulnerability to subsequent challenges and potentiate addictive behaviors.

The crosstalk between brain and periphery: Implications for brain health and disease

Mounting evidence indicates that signaling molecules identified primarily in the peripheral circulation can affect cognitive function in physiological and pathological conditions, including in the development of several neurological diseases. However, considering the properties of the vascular blood-brain barrier (BBB), circulating lipophobic molecules would not be expected to cross this vascular structure. Thus, if and how peripheral lipophobic molecules, such as hormones and cytokines, reach the brain to exert their reported effects remains to be better established. In this review, we will discuss evidence for and against the ability of molecules in the circulation, such as insulin, cytokines, and irisin to reach the brain and mediate the crosstalk between peripheral tissues and the central nervous system (CNS). We hypothesize that in addition to entering the brain via receptor-mediated transcytosis, these circulating molecules can have their transport facilitated by extracellular vesicles or under pathological conditions when the BBB is disrupted. We also discuss the possibility that these circulating molecules access the brain by acting directly on circumventricular organs, which lack the BBB, by local synthesis in the choroid plexus, and via activation of afferent vagal nerves. Advancing the understanding of mechanisms implicated in the transport of blood-borne molecules to the CNS will help us elucidate the contribution of peripheral factors to brain health and disease, and will enable the development of minimally invasive strategies to deliver therapeutic drugs to the brain in neurological disorders.

Coated nanodiamonds interact with tubulin beta-III negative cells of adult brain tissue

Fluorescent nanodiamonds (NDs) coated with therapeutics and cell-targeting structures serve as effective tools for drug delivery. However, NDs circulating in blood can eventually interact with the blood-brain barrier, resulting in undesired pathology. Here, we aimed to detect interaction between NDs and adult brain tissue. First, we cultured neuronal tissue with ND ex vivo and studied cell prosperity, regeneration, cytokine secretion, and nanodiamond uptake. Then, we applied NDs systemically into C57BL/6 animals and assessed accumulation of nanodiamonds in brain tissue and cytokine response. We found that only non-neuronal cells internalized coated nanodiamonds and responded by excretion of interleukin-6 and interferon-γ. Cells of neuronal origin expressing tubulin beta-III did not internalize any NDs. Once we applied coated NDs intravenously, we found no presence of NDs in the adult cortex but observed transient release of interleukin-1α. We conclude that specialized adult neuronal cells do not internalize plain or coated NDs. However, coated nanodiamonds interact with non-neuronal cells present within the cortex tissue. Moreover, the coated NDs do not cross the blood-brain barrier but they interact with adjacent barrier cells and trigger a temporary cytokine response. This study represents the first report concerning interaction of NDs with adult brain tissue.