ABSTRACT
Sialic acid-binding immunoglobulin-like lectins (Siglecs) are members of the immunoglobulin superfamily expressed in most white blood cells of the immune system. The Siglec is a kind of transmembrane proteins that can recognize sialic acid-containing ligands, and it is the most important subgroup of type I lectin. All Siglecs contain at least three domains, including the V-set Ig domain, C2-set Ig domain and transmembrane domain. Some Siglecs contain immune receptor tyrosine-based inhibitory motifs (ITIMs), which are used to transmit inhibitory signals and play an inhibitory role. There are also some Siglecs that do not contain intracellular domains, and they can transmit activation signals through basic amino acids in transmembrane domains to play an activation role. Siglecs not only participate in the regulation of activation, proliferation and apoptosis of immune cells, but also help the immune system to distinguish itself from non-itself by recognizing glycan ligands containing sialic acid. In recent years, studies have shown that Siglecs, as an immune checkpoint, play an important role in the immune regulation in human diseases such as cancer, asthma, allergy, Alzheimer’s disease and autoimmune diseases, and it has received extensive attention. Enhancing or blocking the interaction of sialic acid with Siglecs is an effective strategy for the treatment of cancer, infection, and other diseases. In this review, we describe the classification of Siglecs, their expression in different immune cells and their role in the regulation of immune cell signaling. Emphasis was placed on the role of Siglecs in disease and methods of targeting Siglecs for the treatment of human diseases.
ABSTRACT
Microglial cells are widely distributed in the brain and spinal cord, and usually act as resident immune cells which could provide continuous monitoring roles within the central nervous system. When the cells in the central nervous system are injured, microglial cells are activated and induce a series of biological effects. Recently, several voltage-gated sodium channel subtypes were found to be expressed on the surface of the microglial cells which are able to participate in the regulation of the activation, phagocytosis, secretion of multiple cytokines/chemokines, migration, invasion of microglial cells, and etc. In the present study, the latest progresses on the regulation of voltage-gated sodium channel isoforms on microglial cells were summarized and analyzed. In addition, the mechanism and future research of the relationship between voltage-gated sodium channels and microglial cells were also discussed.
Subject(s)
Animals , Humans , Cytokines , Microglia , Physiology , Protein Isoforms , Voltage-Gated Sodium Channels , PhysiologyABSTRACT
<p><b>BACKGROUND</b>Successful aging (SA) and mild cognitive impairment (MCI) are heterogeneous groups of aging. To explore the heterogeneity, the functional connectivity was studied in these populations.</p><p><b>METHODS</b>The present study utilized functional connectivity magnetic resonance imaging (fcMRI) to investigate default mode network (DMN) in 8 healthy subjects of SA, 8 subjects of usual aging (UA), and 8 MCI patients during verbal fluency tests (VFTs). Functional connectivity (based seeds) of different groups was analyzed by using statistical test.</p><p><b>RESULTS</b>Compared with SA and UA groups, MCI subjects exhibited decreased functional connectivity in the DMN regions, including the inferior parietal lobule and left angular gyrus (t = 3.53, P < 0.001). Compared with UA and MCI groups, the SA elderly exhibited increased functional connectivity in the precuneus (t = 3.53, P < 0.001).</p><p><b>CONCLUSIONS</b>These findings suggested that abnormalities of functional connectivity in DMN might be related with semantic memory impairment in aging. Left angular gyrus and precuneus might be the potential imaging-based biomarker for distinguishing heterogeneous process of elderly.</p>
Subject(s)
Aged , Aged, 80 and over , Female , Humans , Male , Aging , Physiology , Brain , Cognitive Dysfunction , Magnetic Resonance Imaging , Neuropsychological TestsABSTRACT
To reseach GFP reporter gene under the control of chick ovalbumin gene regulatory elements express in the CHO cell and in the primary cell cultures of chicken oviduct. 1.5kb fragment and 2.9kb fragment were amplicated by PCR method, two fragments were subeloned to manmalian expression vector pGFP-N2 by recombinant DNA technology, the CMV promoter was cut off from pGFP-N2, so two expression vectors were constructed, one is the P2.9koval-GFP including promoter, first exon, first intron of chicken ovalbumin gene, the other is the P1.5koval-GFP including first intron of chicken ovalbumin gene. Restriction enzyme digestion and DNA sequence analysis revealed that 5'upstream regions of ovalbumin gene were not only identical to those of the published chicken ovalbumin gene, but also were contained in the recombinant vector. They were transfected into the CHO cell and the primary cell cultures of chicken oviduct by Lipofectin, they were used for fluorescence detection. GFP protein existed in GFP transfected the CHO cell and the primary cell cultures of chicken oviduct. It is demonstrated that GFP reporter gene under the direction of chick ovalbumin gene promoter could be expressed in the CHO cell and in the primary cell cultures of chicken oviduct.