Localization of the human SP3 gene to chromosome 7p14-p15.2. The lack of expression in multiple sclerosis does not reflect abnormal gene organization

Sp3 ameliorated experimental autoimmune encephalomyelitis by triggering Socs3 in Th17 cells

INTRODUCTION

Although it is believed that chronic inflammatory and degenerative diseases of the central nervous system are mediated by autoimmune Th17 cells, the underlying mechanisms remain largely unexplored. Recent studies and our research have revealed that Sp3 was blocked in multiple sclerosis (MS) patients and experimental autoimmune encephalomyelitis (EAE). However, it remained unclear why it is silent and how it regulates Th17 cell differentiation in MS.

OBJECTIVES

This study aimed to explore the impact of Sp3 on Th17 cell-mediated EAE and the underlying mechanism.

METHODS

The effect of Sp3 on the clinical symptoms of EAE was evaluated by scoring, histochemistry, and fast blue (FB) techniques, scRNA-seq data analysis, flow cytometry, ELISA, PCR, WB, immunofluorescence and reporter gene techniques were used to explore the molecular mechanism of Sp3 regulating Th17 cell differentiation.

RESULTS

Injection of overexpression Sp3 lentivirus could significantly ameliorate the EAE progress and clinical symptoms and prevent the polarization of Th1 and Th17 cells both in vivo and in vitro. We confirmed the occurrence of EAE in Sp3+/+CD4Cre mice and Sp3+/- knockout mice. Furthermore, we identified Sp3 as a target of miR-223, which is found to be upregulated in the blood of MS patients, as well as in EAE and Th17 cells. Moreover, knockdown of miR-223 led to a marked improvement in EAE symptoms and a suppression of Th1 and Th17 cell polarization in vivo and in vitro. Mechanistically, Sp3 significantly suppressed RORγt expression and the phosphorylation of Stat3 and Smad2/3 by directly upregulating Socs3. Interestingly, Socs3 was found to regulate Sp3 expression in response to TGF-β1 via a feedback loop. Moreover, Socs3 modulated phospho-Smad2/3 by binding to and degrading the transforming growth factor-β receptor II (TβRII).

CONCLUSION

Thus, our study suggests a novel mechanism involving miR-223/Sp3/Socs3/TGF-β signaling as a potential therapeutic strategy for targeting Th17 cells in immunotherapy.

Identification of potential regulatory long non-coding RNA-associated competing endogenous RNA axes in periplaque regions in multiple sclerosis

Slow-burning inflammation at the lesion rim is connected to the expansion of chronic multiple sclerosis (MS) lesions. However, the underlying processes causing expansion are not clearly realized. In this context, the current study used a bioinformatics approach to identify the expression profiles and related lncRNA-associated ceRNA regulatory axes in the periplaque region in MS patients. Expression data (GSE52139) from periplaque regions in the secondary progressive MS spinal cord and controls were downloaded from the Gene Expression Omnibus database (GEO), which has details on mRNAs and lncRNAs. Using the R software's limma package, the differentially expressed lncRNAs (DElncRNAs) and mRNAs (DEmRNAs) were found. The RNA interactions were also found using the DIANA-LncBase, miRTarBase, and HMDD databases. The Pearson correlation coefficient was used to determine whether there were any positive correlations between DEmRNAs and DElncRNAs in the ceRNA network. Finally, lncRNA-associated ceRNA axes were created based on co-expression and connections between DElncRNA, miRNA, and DEmRNA. We used the Enrichr tool to enrich the biological process, molecular function, and pathways for DEmRNAs and DElncRNAs. A network of DEmRNAs' protein-protein interactions was developed, and the top five hub genes were found using Cytoscape and STRING. The current study indicates that 15 DEmRNAs, including FOS, GJA1, NTRK2, CTNND1, and SP3, are connected to the MS ceRNA network. Additionally, four DElncRNAs (such as TUG1, ASB16-AS1, and LINC01094) that regulated the aforementioned mRNAs by sponging 14 MS-related miRNAs (e.g., hsa-miR-145-5p, hsa-miR-200a-3p, hsa-miR-20a-5p, hsa-miR-22-3p, hsa-miR-23a-3p, hsa-miR-27a-3p, hsa-miR-29b-3p, hsa-miR-29c-3p, hsa-miR-34a-5p) were found. In addition, the analysis of pathway enrichment revealed that DEmRNAs were enriched in the pathways for the "MAPK signaling pathway", "Kaposi sarcoma-associated herpesvirus infection", "Human immunodeficiency virus one infection", "Lipid and atherosclerosis", and "Amphetamine addiction". Even though the function of these ceRNA axes needs to be investigated further, this study provides research targets for studying ceRNA-mediated molecular mechanisms related to periplaque demyelination in MS.

A transcription factor map as revealed by a genome-wide gene expression analysis of whole-blood mRNA transcriptome in multiple sclerosis

Background

Several lines of evidence suggest that transcription factors are involved in the pathogenesis of Multiple Sclerosis (MS) but complete mapping of the whole network has been elusive. One of the reasons is that there are several clinical subtypes of MS and transcription factors that may be involved in one subtype may not be in others. We investigate the possibility that this network could be mapped using microarray technologies and contemporary bioinformatics methods on a dataset derived from whole blood in 99 untreated MS patients (36 Relapse Remitting MS, 43 Primary Progressive MS, and 20 Secondary Progressive MS) and 45 age-matched healthy controls.

Methodology/Principal Findings

We have used two different analytical methodologies: a non-standard differential expression analysis and a differential co-expression analysis, which have converged on a significant number of regulatory motifs that are statistically overrepresented in genes that are either differentially expressed (or differentially co-expressed) in cases and controls (e.g., V$KROX_Q6, p-value <3.31E-6; V$CREBP1_Q2, p-value <9.93E-6, V$YY1_02, p-value <1.65E-5).

Conclusions/Significance

Our analysis uncovered a network of transcription factors that potentially dysregulate several genes in MS or one or more of its disease subtypes. The most significant transcription factor motifs were for the Early Growth Response EGR/KROX family, ATF2, YY1 (Yin and Yang 1), E2F-1/DP-1 and E2F-4/DP-2 heterodimers, SOX5, and CREB and ATF families. These transcription factors are involved in early T-lymphocyte specification and commitment as well as in oligodendrocyte dedifferentiation and development, both pathways that have significant biological plausibility in MS causation.

Human transcription factor Sp3: genomic structure, identification of a processed pseudogene, and transcript analysis

The human transcription factor Sp3 has been widely studied at the translational level and has been described as a regulatory factor for a number of genes. Sp3 is currently characterized as a bifunctional transcription factor having the ability to behave as both an activator and/or a repressor in various promoter regions. Previous translational studies have attempted to determine the basis for these diverse functions with mostly contradictory evidence to date. Little data are available, however, concerning genomic structure, full-length cDNA, potential transcript variants, or location of translation initiation sites for the large isoform of the Sp3 gene. In this study, bacterial artificial chromosome (BAC) sequencing, reverse transcription-polymerase chain reaction (RT-PCR), genomic PCR, and database mining indicate that the Sp3 gene encompasses seven exons spanning more than 55 kb of genomic DNA on Chromosome 2. The 5' end of this sequence contains a large CpG island. This work also detected a processed pseudogene, psiSp3, located on Chromosome 13, spanning approximately 4.0 kb. Northern blot analysis detected three predominant transcripts at 4.0, 6.0 and 2.5 kb. Sequence analysis indicated that alternative splicing of exon 3 allows for multiple transcripts of Sp3. Each sequenced transcript possesses three to five potential translation initiation sites. This diversity at the level of gene expression will likely be key to understanding the diverse functions of Sp3.

Sp3 expression in immune cells: a quantitative study

We previously reported the lack of expression of the bifunctional transcription factor Sp3 in peripheral blood mononuclear cells from most patients with multiple sclerosis (MS) (Grekova et al, 1996). An RT-PCR technique was developed to evaluate Sp3 mRNA levels in peripheral blood mononuclear cell subsets. Semi-quantitative and quantitative competitive RT-PCR assays were used to compare the level of Sp3 expression among subjects and among immune cell subsets. The competitor DNA fragment contained a deletion from the normal Sp3 cDNA sequence. The wild-type Sp3 cDNA and the competitor DNA fragment amplified with equal efficiency, and the two PCR products were distinguished by size. These studies demonstrated that normal CD4(+) and CD8(+) T cells, B cells, and macrophages expressed comparable amounts of Sp3 mRNA. No Sp3 expression could be detected in normal natural killer cells nor in any of these cell types from Sp3-negative MS patients. We propose that transcription of the Sp3 gene is blocked in immune cells from most patients with MS and that this contributes to the development of central nervous system inflammation in the disease.

Epigenetic contributors to the discordance of monozygotic twins

Human monozygotic (MZ) twins estimated to occur once in 250 live births, result from an errant decision by embryonic cell(s) to develop as separate embryos. They are considered genetically identical and any phenotypic discordance between them has been used to implicate the role of environment. More recent literature, however, has questioned these assumptions but the frequency and the nature of any genetic discordance between MZ twins remains poorly understood. We will review published cases of phenotypic and genetic discordance between monozygotic twins to argue that not all discordance between such twins is due to differences in environment. The causes of reduced concordance between MZ twins remains poorly understood. They represent among the challenging aspects of the genetics of complex multi-factorial traits and diseases. A number of questions regarding the published results on MZ twins merit a re-assessment in the light of modern molecular insight of the human genome. Such an assessment is needed in directing future studies on MZ twins. In particular, we will deal with the origin, development, genetic and epigenetic factors that may have implications in discordance of the MZ twin pairs.