Synaptogenesis by Cholinergic Stimulation of Astrocytes.

Astrocytes release numerous factors known to contribute to the process of synaptogenesis, yet knowledge about the signals that control their release is limited. We hypothesized that neuron-derived signals stimulate astrocytes, which respond to neurons through the modulation of astrocyte-released synaptogenic factors. Here we investigate the effect of cholinergic stimulation of astrocytes on synaptogenesis in co-cultured neurons.

Synaptogenesis by Cholinergic Stimulation of Astrocytes.

Astrocytes release numerous factors known to contribute to the process of synaptogenesis, yet knowledge about the signals that control their release is limited. We hypothesized that neuron-derived signals stimulate astrocytes, which respond by signaling back to neurons through the modulation of astrocyte-released synaptogenic factors. Here we investigate the effect of cholinergic stimulation of astrocytes on synaptogenesis in co-cultured neurons.

Pathogenic T cell cytokines in multiple sclerosis.

Multiple sclerosis (MS) is an inflammatory, demyelinating disease of the central nervous system that is believed to have an autoimmune etiology. As MS is the most common nontraumatic disease that causes disability in young adults, extensive research has been devoted to identifying therapeutic targets. In this review, we discuss the current understanding derived from studies of patients with MS and animal models of how specific cytokines produced by autoreactive CD4 T cells contribute to the pathogenesis of MS.

Myelin-specific CD8+ T cells exacerbate brain inflammation in CNS autoimmunity.

Multiple sclerosis (MS) is an inflammatory, demyelinating disease of the CNS. Although CD4+ T cells are implicated in MS pathogenesis and have been the main focus of MS research using the animal model experimental autoimmune encephalomyelitis (EAE), substantial evidence from patients with MS points to a role for CD8+ T cells in disease pathogenesis. We previously showed that an MHC class I-restricted epitope of myelin basic protein (MBP) is presented in the CNS during CD4+ T cell-initiated EAE.

Co-Culture of Neurons and Microglia.

Microglia, the resident immune cells of the brain, have been implicated in numerous neurodegenerative and neurodevelopmental diseases. Activation of microglia by a variety of stimuli induces the release of factors, including pro- and anti-inflammatory cytokines and reactive oxygen species, that contribute to modulating neuro-inflammation and oxidative stress, two crucial processes linked to disorders of the central nervous system. The in vitro techniques described here will provide a set of protocols for the isolation and plating of primary cerebellar granule neurons, primary cortical microglia from a mixed glia culture, and methods for co-culturing both cell types.

Microglia mediate diesel exhaust particle-induced cerebellar neuronal toxicity through neuroinflammatory mechanisms.

In addition to the well-established effects of air pollution on the cardiovascular and respiratory systems, emerging evidence has implicated it in inducing negative effects on the central nervous system. Diesel exhaust particulate matter (DEP), a major component of air pollution, is a complex mixture of numerous toxicants. Limited studies have shown that DEP-induced dopaminergic neuron dysfunction is mediated by microglia, the resident immune cells of the brain.

Mechanisms of Neuroprotection by Quercetin: Counteracting Oxidative Stress and More.

Increasing interest has recently focused on determining whether several natural compounds, collectively referred to as nutraceuticals, may exert neuroprotective actions in the developing, adult, and aging nervous system. Quercetin, a polyphenol widely present in nature, has received the most attention in this regard. Several studies in vitro, in experimental animals and in humans, have provided supportive evidence for neuroprotective effects of quercetin, either against neurotoxic chemicals or in various models of neuronal injury and neurodegenerative diseases.

Role of glutamate receptors in tetrabrominated diphenyl ether (BDE-47) neurotoxicity in mouse cerebellar granule neurons.

The polybrominated diphenyl ether (PBDE) flame retardants are developmental neurotoxicants, as evidenced by numerous in vitro, animal and human studies. PBDEs can alter the homeostasis of thyroid hormone and directly interact with brain cells. Induction of oxidative stress, leading to DNA damage and apoptotic cell death is a prominent mechanism of PBDE neurotoxicity, though other mechanisms have also been suggested.

Neurotoxicity of traffic-related air pollution.

The central nervous system is emerging as an important target for adverse health effects of air pollution, where it may contribute to neurodevelopmental and neurodegenerative disorders. Air pollution comprises several components, including particulate matter (PM) and ultrafine particulate matter (UFPM), gases, organic compounds, and metals. An important source of ambient PM and UFPM is represented by traffic-related air pollution, primarily diesel exhaust (DE).

The brominated flame retardant BDE-47 causes oxidative stress and apoptotic cell death in vitro and in vivo in mice.

Polybrominated diphenyl ethers (PBDEs), used for decades as flame retardants, have become widespread environmental contaminants. Exposure is believed to occur primarily through diet and dust, and infants and toddlers have the highest body burden, raising concern for potential developmental neurotoxicity. The exact mechanisms of PBDE neurotoxicity have not been elucidated, but two relevant modes of action relate to impairment of thyroid hormone homeostasis and to direct effects on brain cells causing alterations in signal transduction, oxidative stress and apoptotic cell death.

Synaptic structure quantification in cultured neurons.

Behavioral problems (e.g., learning and memory) following developmental exposure to toxicants suggests that dysregulation of the process of synapse formation and function may occur.

Quantification of synaptic structure formation in cocultures of astrocytes and hippocampal neurons.

The ability to quantify changes of synaptic structure, whether associated with the formation of synapse in early development or the degeneration of synapses in adult life in an in vitro culture system, is important for understanding the underlying mechanisms. Astrocytes play a vital role in neuronal development and functioning, including synapse formation and stabilization. The method described in this chapter allows for the determination of the modulation by astrocytes of synaptic structure formation in hippocampal neurons.