Biological characteristics and functions of NG2-glia / 生理学报

NG2-glia are a major type of glial cells that are widely distributed in the central nervous system (CNS). Under physiological conditions, they mainly differentiate into oligodendrocytes and contribute to the myelination of axons, so they are generally called oligodendrocyte progenitor cells. Emerging evidence suggests that NG2-glia not only act as the precursors of oligodendrocytes but also possess many other biological properties and functions. For example, NG2-glia can form synapse with neurons and participate in energy metabolism and immune regulation. Under pathological conditions, NG2-glia can also differentiate into astrocytes, Schwann cells and even neurons, which are involved in CNS injury and repair. Therefore, a deeper understanding of the biological characteristics and functions of NG2-glia under physiological and pathological conditions will be helpful for the treatment of CNS injury and disease. This article reviews the recent advances in the biological characteristics and functions of NG2-glia.

Glial cells function as neural stem cells and progenitor cells / 生理学报

Glial cells, including astrocytes, oligodendrocyte progenitor cells (OPCs), NG2-glia, etc, are broadly distributed throughout the central nervous system (CNS). Also, it has been well known that glial cells play multi-roles in physiological and pathological processes in the CNS, such as maintaining homeostasis, providing neurotrophins for neurons and regulating neural signal transmission. Recently, increasing evidence showed that glial cells may also function as neural stem/progenitor cells and contribute to adult neurogenesis or neuroregeneration. In pathological conditions, for instance, astrocytes and OPCs could be activated to proliferate and differentiate. When cultured in vitro, they could form neurospheres which possess the ability to differentiate into astrocytes, oligodendrocytes and neurons. Additionally, forced expression of exogenous genes in astrocytes and NG2-glia can successfully reprogram them into neurons, which may also be suggestive of their stem/progenitor cell features. Here, we review current knowledge of the stem cell-like properties of glial cells, including what types of glial cells can function as stem/progenitor cells, how they can acquire the stem/progenitor potential and what progenies can be produced. These insights may foster a better understanding of glial cell biology and function in physiological or pathological processes in the CNS and lead to the idea of using the stem/progenitor-like glial cells as endogenous cell source for neural repair.

Astrocytes as therapeutic targets after spinal cord injury / 生理学报

Spinal cord injury (SCI) is a challenging medical problem in the field of neurology, showing high incidence rate, disability rate, treatment cost and low-aged trend. Despite the clinical application of drug intervention, surgical treatment and modern rehabilitation training, no ideal curative effect has been achieved. Therefore, future study is necessary to clarify detailed pathological mechanism of SCI and identify the potential target cells for therapeutic intervention. In the central nervous system (CNS), astrocytes are the most abundant and widely distributed glial cells which play multiple key roles in maintaining homeostasis of the CNS in physiological and pathological conditions. Increasing evidence indicates that astrocytes are ideal therapeutic target cells for SCI. Here, we review current knowledge of the roles of astrocytes in the pathological reaction after SCI, astroglial transplantation and astrocyte reprogramming.

Structural, mechanistic and functional insights into topoisomerase II / 生理学报

Topoisomerases are nuclear enzymes that regulate the overwinding or underwinding of DNA helix during replication, transcription, recombination, repair, and chromatin remodeling. These enzymes perform topological transformations by providing a transient DNA break, through which the unique problems of DNA entanglement that occur owing to unwinding and rewinding of the DNA helix can be resolved. In mammals, topoisomerases are classified into two types, type I topoisomerase (Top1) and type II topoisomerase (Top2), depending on the number of strands cut in one round of action. Top1 induces single-strand breaks in DNA, and Top2 induces double-strand breaks. In cells from vertebrate species, there are two forms of Top2, designated alpha and beta. Top2α is involved in the cellular proliferation and pluripotency, while Top2β plays key roles in neurodevelopment. In this review, we cover recent advances in structural, mechanistic and functional insights into Top2.

Correlation between children's dental decay and the contents of saliva CCL28 and secretory immunoglobulin A / 中南大学学报(医学版)

OBJECTIVE@#To explore the association of the dental decay of children with the contents of chemokine CCL28 and secretory immunoglobulin A (sIgA) in saliva.@*METHODS@#A total of 108 children in 2 kindergartens of Changsha, with age from 3 to 5 years old, were enrolled for this study. The saliva was collected from these children when they were in the examination of mouth. Th e children were divided into 3 groups: A non-caries group [dynamical mean-field theory (DMFT)=0], a low caries group (DMFT=1-4) and a high caries group (DMFT ≥ 5). Th e contents of CCL28 and sIgA were measured by ELISA.@*RESULTS@#The contents of CCL28 and sIgA in saliva were (121.22 ± 32.63) pg/mL and (16.49 ± 8.02) μg/mL, respectively. A positive linear correlation was found between the CCL28 content and sIgA content in saliva (r=0.734). Th e CCL28 and sIgA contents in saliva were positively correlated with the degree of dental caries in children (P<0.05).@*CONCLUSION@#The dental decay of children leads to the secretion of chemokine CCL28, which promotes the secretion of sIgA in saliva.

Relationship between drug resistance and the expression of NF-kappaB induced in leukemic cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To explore the relationship between drug resistance of leukemic cells and the expression of both IkappaB-alpha and NF-kappaB associated with apoptosis induced by arsenic trioxide (As2O3) in K562 and K562/ADR cells.</p><p><b>METHODS</b>Apoptosis was induced in K562 and K562/ADR cells cultured with As2O3 in different concentrations. Western blot was used to analyze the expression of NF-kappaB in nuclear and IkappaB-alpha in cytoplasm of these cells. Apoptosis and degradation of IkappaB-alpha protein were also observed by flow cytometry.</p><p><b>RESULTS</b>After exposure to As2O3, the ratio of apoptosis cells in K562/ADR was significantly lower than that in K562 cells. K562/ADR [(6.33+/-1.51)%] and K562 cells [(13.25+/-1.83)%] cultured with 1 micromol/L As2O3 were in apoptosis. When cultured with 4 micromol/L As2O3, the apoptosis cells increased to (8.00+/-1.47)% and (50.56+/-8.62)%, respectively. The level of IkappaB-alpha in K562 cytoplasm was down-regulated from 88.07% to 49.21% after As2O3 stimulation, while NF-kappaB in nuclear was up-regulated, that was not found in K562/ADR cells.</p><p><b>CONCLUSION</b>As2O3 could induce apoptosis of K562 cells, associated with the degradation of IkappaB-alpha and the activation of NF-kappaB. There are an elevated expression of NF-kappaB and resistance to apoptosis induced by As2O3 in K562/ADR cells.</p>