A new concept of neuroscience to be known in 2020: axon nanofractures - glial cell subtypes - the real hardness of the brain.

In mammalian brains, the ratio of glial cells to neurons is about 10:1.in the central nervous system (CNS), there are mainly astrocytes, oligodendrocytes and microglia.although many neuronal subtypes have been identified, the concept of glial heterogeneity is still in its infancy. There are many ways to classify neurons, such as afferent neurons, efferent neurons and intermediate neurons according to their functions.according to their morphology, they can be divided into unipolar neurons, bipolar neurons and multipolar neurons.according to the release of neurotransmitters, it can be divided into cholinergic neurons, serotonin neurons and so on.compared with neurons, glial cells have fewer types.microglia can be divided into three types: M0 type under resting state. After activation, microglia can be further divided into proinflammatory M1 type and anti-inflammatory M2 type by secreting inflammatory factors.this classification has limitations, so in recent years, we have studied the regional and functional specificity of microglia by transcriptomics in order to find a more comprehensive description of the types of microglia.in 2019, the team of Netherlands Institute of neuroscience conducted transcriptomic analysis on microglia isolated from the gray matter and white matter of multiple sclerosis and healthy adults after death, and found that there was a clear difference between them. The expression of IFN-I gene in gray matter was higher than that of NF KB signal pathway gene in white matter.the function of white matter microglia enrichment gene is mainly involved in lipid metabolism, while that of gray matter microglia enrichment gene is mainly involved in glucose and iron metabolism.these results suggest that the characteristics of microglia in different brain regions may be different in multiple sclerosis disease.this specificity also exists in oligodendrocytes.oligodendrocytes are myelin forming cells of adult central nervous system, providing insulation for neurons and promoting jumping conduction.because oligodendrocyte progenitor cells are precursors of these cells, their ability to proliferate and differentiate in the adult brain has attracted extensive attention due to its inherent regenerative potential.oligodendrocyte progenitor cells are highly responsive to environmental cues and can communicate with other types of nerve cells, which indicates that these cells are not only involved in the pathogenesis of demyelinating diseases, but also may be involved in the pathogenesis of neurodegenerative diseases and mental diseases.the birth of the concept of oligodendrocyte subgroup the first new concept is the specific oligodendrocyte subtype in multiple sclerosis.in 2019, scientists from Karolinska Institute in Stockholm, Sweden, used RNA sequencing from 5 postmortem samples of normal adults to discover seven types of oligodendrocytes, and further found specific markers of these cell groups.however, there are only four types of oligodendrocytes in MS, and there are specific changes.the disease-specific oligodendrocyte subtype has been further verified in the follow-up studies. They further found that there are obvious stress signaling pathways and mhci molecules up-regulated in oligodendrocytes, which may be the potential mechanism for the existence of specific oligodendrocyte subtypes in this disease.whether microglia or oligodendrocytes, although transcriptomics can reveal the existence of regional or disease-related cluster characteristics, if we can not find the biomarkers of these clusters of cells, we can not carry out specific research, then the significance of the existence of this subgroup will be greatly reduced.physical properties of brain tissue the second noteworthy feature is the physical properties produced in the process of multiple sclerosis.in 2019, researchers from the Department of biology of New York University measured the elasticity of brain parenchyma (i.e., the physical properties of tissues) in patients with multiple sclerosis (MS) using atomic force microscopy (AFM). The results showed that acute demyelination resulted in a decrease in tissue hardness and recovery with myelination regeneration.chronic demyelination is characterized by an increase in tissue hardness, which is related to the deposition of extracellular matrix components.previous studies have found that oligodendrocyte progenitor cells have the characteristics of mechanical sensitive cells, and their ability to generate myelin sheath cells is affected by the physical characteristics of the surrounding environment.nanofracture of axon 1. Oxidative stress and tumor nutrition technology set off a boom in functional research. Another interesting concept is "nano fracture" of axon.the researchers used a multiphoton in vivo microscope to observe the level of cytoplasmic calcium in the demyelinating mice. The results showed that calcium ions accumulated near the plasma membrane of axons during the early local axonal degeneration.finally, they found that there was a nanoscale (less than 10 nm) rupture in the plasma membrane, which caused calcium influx.when readers see that these concepts only exist in multiple sclerosis, Xiaobian says that the concepts worthy of attention in the field of neuroscience are exaggerated? This question was raised repeatedly by the editor when sorting out these materials. However, after searching for data, it was found that these concepts did not only exist in multiple sclerosis.for example, the concept of glial cell subtype has appeared in Alzheimer's disease, Parkinson's disease, epilepsy and other diseases; the concept of brain parenchyma hardness has also appeared in the process of aging.these concepts appear frequently and are relatively new in 2019.conclusion: in general, the article summarizes the interesting new concepts in the pathogenesis of multiple sclerosis in 2019, such as oligodendrocyte subtype, elasticity of brain parenchyma, and "nano fracture" of axon plasma membrane. These concepts also provide new directions for the treatment of other neurodegenerative diseases.references; 1. Van der Poe m, ulas T, mizee Mr, et al. Transcriptional profiling of human microglia returns grey white matter heterogeneity and multiple sclerosisassociatedchanges. NAT commun 2019; 10: 1139.2. J ü Kel s, agirre e, Mendanha FALC ó o a, et al 2019; 566: 543–47. 3.Schirmer L, Velmeshev D, Holmqvist S, et al. Neuronal vulnerability and multilineage diversity in multiple sclerosis. Nature 2019; 573: 75–82. 4.Urbanski MM, Brendel MB, Melendez-Vasquez CV. Acute and chronic demyelinated CNS lesions exhibit opposite elastic properties. Sci Rep 2019; 9: 999. 5.Witte ME, Schumacher AM,Mahler CF, et al. Calcium influx through plasma-membrane nanoruptures drives axon degeneration in a model of multiple sclerosis. Neuron 2019; 101: 615–24.6.Emerging concepts in neuroscience research: 2019 Highlights cover pictures and article pictures are from the history of the Internet related articles: 2019 heavy summary: the "Chinese power" in the field of Neuroscience (year-end Edition) nature back to back article: scientists find neurons that identify positive emotions and fear negative emotions at the same time Progress made by domestic scientists in the field of Neuroscience (National Day edition) Rewrite textbooks! 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