Neuroscience

A neuron is a cell that processes and transmits information through electrical and chemical signals. There are trillions of them in the human brain. Neurons have three primary parts: dendrites, cell body, and axon. Dendrites detect changes in electrical potential across the surface of neurons while changing the direction of these signals to transmit them toward or away from its cell body. The cell body is where a neuron integrates incoming signals and decides how to transmit them along the axon.

Neurons typically respond to neurotransmitters released from other neurons through a process called a 'synapse'. There are two main types of synapses: electrical and chemical. In an electrical synapse, voltage-gated ion channels in one neuron open up if it fires which causes positively charged ions to rush into the adjacent neuron, triggering it to fire as well. In this scenario, both neurons involved can be either excitatory or inhibitory to how they impact their target neurons due to how each conducts its own incoming signals. Chemical synapses on the other hand use vesicles filled with neurotransmitter molecules like glutamate or GABA (another excitatory neurotransmitter) which activate neurotransmitter receptors embedded in the membrane of the postsynaptic neuron. Once activated, these neurotransmitter receptors cause ion channels to open up which causes ions like sodium or potassium to rush into the receiving neuron and impact how much voltage difference (membrane potential) it has across its plasma membrane. To keep balance between how much excitatory and inhibitory input a neuron receives, neurons can either release more neurotransmitters than they receive to be excitatory or use enzymes to break down excess neurotransmitters for example, so that they can counterbalance their effect on downstream neurons.

Some common neuronal markers are NeuN, β3-Tubulin, MAP2, NCAM, GAP-43, Tyrosine Hydroxylase, Synaptophysin, vGLUT1, vGLUT2, PSD95 and much more.

Glial cells are the most abundant cell type in your brain. Previously glial cells were thought to be non-functional glue for neurons, however, years of research have highlighted their key role in regulating neuron activity. The main glial cells are microglia, astrocytes and oligodendrocyte cells.

Glial cells are responsible for repairing damage to neurons, removing debris after neural injury and helping them communicate with each other. As well as this, glial cells are responsible for producing myelin which is a fatty material that insulates the axons of neurons. This myelin has been shown to have effects on the speed of action potential conduction.

Microglial cells are brain cells that function as part of the immune system. Microglia act as the first line of defense against infections and pathogens, secreting inflammatory factors to protect surrounding tissue. They also act as scavengers, clearing cellular debris and infectious agents.  

Microglial cells can be found throughout the entire brain with particularly high concentrations in the meninges and choroid plexus, with sparse expression across cortical layers and scarcely any expression in white matter. Microglial dysfunction has been implicated in a number of neurological diseases including Parkinson's disease, Alzheimer's disease (AD), Multiple Sclerosis (MS), stroke, amyotrophic lateral sclerosis (ALS) and Huntington's disease as well as in acute neurodegenerative conditions such as trauma or epilepsy. Some common markers for microglia are the expression of CD45, CX3CR1, ASC, HS1, TMEM119, CD11b and IBA1/AIF-1.

Astrocytes have many functions including regulation of blood flow, provision of nutrients to surrounding tissue, clearance of neurotransmitters from the extracellular space, regulating neuronal synapses and maintaining extracellular ion concentrations by buffering potassium ions. Astrocytes also express glutamate receptors on their cell membrane to allow for direct communication between neurons and astrocytes in a process called synaptically-driven astrocyte calcium waves or SDACs.

Some common astrocyte markers are glial fibrillar acidic protein (GFAP) and the gap junction protein connexin 30 (Cx30). As well as this, there are markers for mature astrocytes such as aquaporin 4, aldolase C (AldoC), glutamate transporter-1 (Glt1), S100 calcium-binding protein B (S100b) and aldehyde dehydrogenase family 1 member L1 (Aldh1L1).

Oligodendrocytes are a type of glial cell in the central nervous system. Oligodendrocytes have very few branches compared to neurons. Oligodendrocytes are responsible for forming the myelin sheath surrounding axons. Oligodendrocytes also supply neurons with nutrients and oxygen and they remove waste products from neurons. Oligodendrocytes are produced in large numbers by oligodendrocyte stem cells, as well as Oligodendrocyte progenitor cells that originate from Oligodendrocyte precursor cells (OPCs).

Some common markers for Oligodendrocytes are 2’,3’-cyclic nucleotide 3’-phosphohydrolase (CNPase), proteolipid protein (PLP1), myelin basic protein (MBP), Sox10, myelin oligodendrocyte glycoprotein (MOG) and carbonic anhydrase II.

Neurodegenerative disorders are classified as the progressive loss and dysfunction of neurons. Some common neurodegenerative disorders include Multiple Sclerosis, Alzheimer's disease, Amyotrophic Lateral Sclerosis, Huntington's disease, Motor Neuron Disease, Parkinson’s disease, Progressive Supranuclear Palsy, Charcot-Marie Tooth disease and much more.

The listed disorders, among others, are debilitating conditions which affect the ability of people to perform everyday tasks such as walking, talking, breathing, swallowing and much more. At present, there are treatments to help slow the progression of neurodegenerative disorders but there are no cures for these diseases.

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• Toll-like Receptor Signalling in Neurodegenerative Disease
• The Ubiquitin Proteasome System in Neurodegenerative disease
• TLX as a Novel Therapeutic Target
• Multiple Sclerosis and Stem Cells
• Neurofilament Light chain (NEFL) as a biomarker for neuronal damage
• What are the stages of Parkinson's disease?

Neuroscience biomarkers are useful research tools which can contribute towards both early detections and the development of therapeutic interventions. Biomarkers can provide information on the stage of the disease and it’s progression.

Assay Genie provides a wide variety of neuroscience biomarker products. In particular, Assay Genie has a selection of Tau and Neurofilament Light Chain (NEFL or Nfl) ELISA kits, Antibodies, Proteins and Assays.

Tau protein is encoded by the MAPT gene (microtubule-associated Tau gene) and it is expressed in the CNS (central nervous system) and the PNS (peripheral nervous system). Tau protein plays a role in axonal transport, stabilization of microtubules and tubulin polymerization into microtubules. There have been many different tau alterations observed in neurodegenerative disorders and the biochemical characterization of tau inclusions has allowed for an improved diagnosis of neurodegenerative diseases and it has shown to have potential as a diagnostic biomarker.

NEFL are cytoskeleton proteins which are made up of 3 main subunits (heavy, middle and light chain). NEFL is located in the peripheral and central nervous system and it plays a role in the determination of axonal caliber and the growth of axons. NEFL has been shown to be a promising biomarker for neurodegenerative disorders. Studies have shown that NEFL levels can provide information on the stage of the disease and it’s progression. As well as this, a treatment response can be monitored through analyzing the levels of NEFL present in blood.