scholarly journals An investigation of genetic polymorphisms in Heparan Sulfate Proteoglycan core proteins and key modification enzymes in an Australian Caucasian multiple sclerosis population

2020 ◽  
Author(s):  
Rachel K Okolicsanyi ◽  
Julia Bluhm ◽  
Cassandra Miller ◽  
Lyn R Griffiths ◽  
Larisa M Haupt

Abstract Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disease affecting the central nervous system in young adults. Heparan sulfate proteoglycans (HSPGs) are ubiquitous to the cell surface and the extracellular matrix. HSPG biosynthesis is a complex process involving enzymatic attachment of heparan sulfate (HS) chains to a core protein. HS side chains mediate specific ligand and growth factor interactions directing cellular processes including cell adhesion, migration and differentiation. Two main families of HSPGs exist, the syndecans (SDC1-4) and glypicans (GPC1-6). The SDCs are transmembrane proteins, while the GPC family are GPI-linked to the cell surface. SDC1 has well-documented interactions with numerous signalling pathways. Genome wide association studies (GWAS) have identified regions of the genome associated with MS including a region on chromosome 13 containing GPC5 and GPC6. International studies have revealed significant associations between this region and disease development. The exostosin-1 (EXT1) and sulfatase-1 (SULF1) are key enzymes contributing to the generation of HS chains. EXT1, with documented tumour suppressor properties, is involved in initiation and polymerisation of the growing HS chain. SULF1 removes 6- O -sulfate groups from HS chains, affecting protein-ligand interactions and subsequent downstream signalling with HS modification potentially having significant effects on MS progression. In this study we identified significant associations between single nucleotide polymorphisms in SDC1, GPC5 and GPC6 and MS in an Australian Caucasian case control population. Further significant associations in these genes were identified when the population was stratified by sex and disease subtype. No association was found for EXT1 or SULF1.

2020 ◽  
Author(s):  
Rachel K Okolicsanyi ◽  
Julia Bluhm ◽  
Cassandra Miller ◽  
Lyn R Griffiths ◽  
Larisa M Haupt

Abstract Multiple Sclerosis (MS) is a chronic inflammatory demyelinating disease affecting the central nervous system in young adults. Heparan sulfate proteoglycans (HSPGs) are ubiquitous to the cell surface and the extracellular matrix. HSPG biosynthesis is a complex process involving enzymatic attachment of heparan sulfate (HS) chains to a core protein. HS side chains mediate specific ligand and growth factor interactions directing cellular processes including cell adhesion, migration and differentiation. Two main families of HSPGs exist, the syndecans (SDC1-4) and glypicans (GPC1-6). The SDCs are transmembrane proteins, while the GPC family are GPI-linked to the cell surface. SDC1 has well-documented interactions with numerous signalling pathways. Genome wide association studies (GWAS) have identified regions of the genome associated with MS including a region on chromosome 13 containing GPC5 and GPC6. International studies have revealed significant associations between this region and disease development. Exostosin-1 (EXT1) and sulfatase-1 (SULF1) are two enzymes responsible for the generation of HS chains. EXT1, with documented tumour suppressor properties, is involved in initiation and polymerisation of the growing HS chain. SULF1 removes 6- O -sulfate groups from HS chains, thereby affecting protein-ligand interactions and subsequent downstream signalling with HS modification potentially having significant effects on MS progression. In this study we identified significant associations between single nucleotide polymorphisms in SDC1, GPC5 and GPC6 and MS in an Australian Caucasian case control population. Further significant associations in these genes were identified when the population was stratified by sex and disease subtype. No association was found for EXT1 or SULF1.


1992 ◽  
Vol 263 (3) ◽  
pp. L348-L356 ◽  
Author(s):  
W. M. Maniscalco ◽  
M. H. Campbell

Type II alveolar epithelial cells interact with the extracellular matrix via cell surface receptors for matrix ligands. Cell surface proteoglycans, which are hydrophobic due to their membrane insertion domains, are one of several classes of molecules that may be receptors for matrix ligands. To analyze the hydrophobic proteoglycans synthesized by adult alveolar type II cells, we labeled these cells with 35SO4 and [3H]leucine in short-term primary cultures. Cell-associated hydrophobic proteoglycans and culture medium-derived proteoglycans were purified and characterized. Both the hydrophobic proteoglycans and medium-derived proteoglycans, which were not hydrophobic, had mainly heparan sulfate glycosaminoglycans. Analysis of core proteins of the hydrophobic proteoglycans showed three proteins, 47, 65, and 90 kDa. The 47- and 65-kDa core proteins were substituted only with heparan sulfate chains. The 90-kDa core protein was seen only after digestion with both heparitinase and chondroitin ABC lyase, suggesting it was a hybrid having both heparan sulfate and chondroitin-dermatan sulfate chains. These findings were confirmed by iodination of the core proteins. The hydrophobic cell-associated proteoglycans inserted into artificial liposomes, whereas the medium-derived molecules did not. These data document heterogeneity in core protein and glycosaminoglycan chains among hydrophobic proteoglycans synthesized in vitro by adult alveolar type II cells. These molecules may have diverse functions in regulating type II cell interaction with the extracellular matrix.


2000 ◽  
Vol 148 (4) ◽  
pp. 811-824 ◽  
Author(s):  
Marilyn L. Fitzgerald ◽  
Zihua Wang ◽  
Pyong Woo Park ◽  
Gillian Murphy ◽  
Merton Bernfield

The syndecan family of four transmembrane heparan sulfate proteoglycans binds a variety of soluble and insoluble extracellular effectors. Syndecan extracellular domains (ectodomains) can be shed intact by proteolytic cleavage of their core proteins, yielding soluble proteoglycans that retain the binding properties of their cell surface precursors. Shedding is accelerated by PMA activation of protein kinase C, and by ligand activation of the thrombin (G-protein–coupled) and EGF (protein tyrosine kinase) receptors (Subramanian, S.V., M.L. Fitzgerald, and M. Bernfield. 1997. J. Biol. Chem. 272:14713–14720). Syndecan-1 and -4 ectodomains are found in acute dermal wound fluids, where they regulate growth factor activity (Kato, M., H. Wang, V. Kainulainen, M.L. Fitzgerald, S. Ledbetter, D.M. Ornitz, and M. Bernfield. 1998. Nat. Med. 4:691–697) and proteolytic balance (Kainulainen, V., H. Wang, C. Schick, and M. Bernfield. 1998. J. Biol. Chem. 273:11563–11569). However, little is known about how syndecan ectodomain shedding is regulated. To elucidate the mechanisms that regulate syndecan shedding, we analyzed several features of the process that sheds the syndecan-1 and -4 ectodomains. We find that shedding accelerated by various physiologic agents involves activation of distinct intracellular signaling pathways; and the proteolytic activity responsible for cleavage of syndecan core proteins, which is associated with the cell surface, can act on unstimulated adjacent cells, and is specifically inhibited by TIMP-3, a matrix-associated metalloproteinase inhibitor. In addition, we find that the syndecan-1 core protein is cleaved on the cell surface at a juxtamembrane site; and the proteolytic activity responsible for accelerated shedding differs from that involved in constitutive shedding of the syndecan ectodomains. These results demonstrate the existence of highly regulated mechanisms that can rapidly convert syndecans from cell surface receptors or coreceptors to soluble heparan sulfate proteoglycan effectors. Because the shed ectodomains are found and function in vivo, regulation of syndecan ectodomain shedding by physiological mediators indicates that shedding is a response to specific developmental and pathophysiological cues.


2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Lynn Abou-Khater ◽  
Fouad Maalouf ◽  
Abdulqader Jighly ◽  
Alsamman M. Alsamman ◽  
Diego Rubiales ◽  
...  

AbstractWeeds represent one of the major constraints for faba bean crop. The identification of molecular markers associated with key genes imparting tolerance to herbicides can facilitate and fasten the efficient and effective development of herbicide tolerant cultivars. We phenotyped 140 faba bean genotypes in three open field experiments at two locations in Lebanon and Morocco against three herbicide treatments (T1 metribuzin 250 g ai/ha; T2 imazethapyr 75 g ai/ha; T3 untreated) and one in greenhouse where T1 and T3 were applied. The same set was genotyped using genotyping by sequencing (GBS) which yield 10,794 high quality single nucleotide polymorphisms (SNPs). ADMIXTURE software was used to infer the population structure which revealed two ancestral subpopulations. To identify SNPs associated with phenological and yield related traits under herbicide treatments, Single-trait (ST) and Multi-trait (MT) Genome Wide Association Studies (GWAS) were fitted using GEMMA software, showing 10 and 14 highly significant associations, respectively. Genomic sequences containing herbicide tolerance associated SNPs were aligned against the NCBI database using BLASTX tool using default parameters to annotate candidate genes underlying the causal variants. SNPs from acidic endochitinase, LRR receptor-like serine/threonine-protein kinase RCH1, probable serine/threonine-protein kinase NAK, malate dehydrogenase, photosystem I core protein PsaA and MYB-related protein P-like were significantly associated with herbicide tolerance traits.


2011 ◽  
Vol 17 (5) ◽  
pp. 634-636 ◽  
Author(s):  
Marcelo Matiello ◽  
Brian G Weinshenker ◽  
Elizabeth J Atkinson ◽  
Janet Schaefer-Klein ◽  
Orhun H Kantarci

Genome-wide association studies have identified an association between two intronic single nucleotide polymorphisms (SNPs), rs12722489 and rs2104286, in the interleukin-2 receptor alpha-chain gene ( IL2RA) and susceptibility to multiple sclerosis (MS). We studied these SNPs in association with susceptibility to and severity of MS in a population-based cohort of 220 patients from Olmsted County, Minnesota, compared with 442 matched controls. We sequenced the exons, splice sites and 5’ and 3’ untranslated regions in 27 randomly selected MS patients (powered for allele frequency ≥0.04) to search for mutations. No novel missense mutation was identified. Two patients (7.5%) had an exon 2 SNP ( rs4308625) and two patients had an exon 4 SNP ( rs2228149), both synonymous.


Cells ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 285 ◽  
Author(s):  
Marina von Essen ◽  
Helle Søndergaard ◽  
Eva Petersen ◽  
Finn Sellebjerg

Multiple sclerosis (MS) is an immune-mediated demyelinating disease characterized by central nervous system (CNS) lymphocyte infiltration, abundant production of pro-inflammatory cytokines, and inappropriate activation of Th1 and Th17 cells, B cells, and innate immune cells. The etiology of MS is complex, and genetic factors contribute to disease susceptibility. Genome-wide association studies (GWAS) have revealed numerous MS-risk alleles in the IL-6/STAT3, IL-12/STAT4, and IL-23/STAT3-pathways implicated in the differentiation of Th1 and Th17 cells. In this study, we investigated the signaling properties of these pathways in T, B, and NK cells from patients with relapsing-remitting MS (RRMS) and healthy controls, and assessed the genetic contribution to the activity of the pathways. This revealed a great variability in the level of STAT-pathway molecules and STAT activation between the cell types investigated. We also found a strong donor variation in IL-6, IL-12, and IL-23 responsiveness of primed CD4+ T cells. This variation could not be explained by a single MS-risk variant in a pathway component, or by an accumulation of multiple STAT-pathway MS-risk SNPs. The data of this study suggests that other factors in cohesion with the genetic background contribute to the responsiveness of the IL-6/STAT3, IL-12/STAT4, and IL-23/STAT3-pathways.


1996 ◽  
Vol 132 (6) ◽  
pp. 1209-1221 ◽  
Author(s):  
C S Lebakken ◽  
A C Rapraeger

Syndecan-1 is a cell surface proteoglycan containing a highly conserved transmembrane and cytoplasmic domain, and an extracellular domain bearing heparan sulfate glycosaminoglycans. Through these domains, syndecan-1 is proposed to have roles in growth factor action, extracellular matrix adhesion, and cytoskeletal organization that controls cell morphology. To study the role of syndecan-1 in cell adhesion and cytoskeleton reorganization, mouse syndecan-1 cDNA was transfected into human Raji cells, a lymphoblastoid cell line that grows as suspended cells and exhibits little or no endogenous cell surface heparan sulfate. High expressing transfectants (Raji-Sl cells) bind to and spread on immobilized thrombospondin or fibronectin, which are ligands for the heparan sulfate chains of the proteoglycan. This binding and spreading as not dependent on the cytoplasmic domain of the core protein, is mutants expressing core proteins with cytoplasmic deletions maintain the ability to spread. The spreading is mediated through engagement of the syndecan-1 core protein, as the Raji-S 1 cells also bind to and spread on immobilized mAb 281.2, an antibody specific for the ectodomain of the syndecan-1 core protein. Spreading on the antibody is independent of the heparan sulfate glycosaminoglycan chains and can be inhibited by competition with soluble mAb 281.2. The spreading can be inhibited by treatment with cytochalasin D or colchicine. These data suggest that the core protein of syndecan-1 mediates spreading through the formation of a multimolecular signaling complex at the cell surface that signals cytoskeleton reorganization. This complex may form via intramembrane or extracellular interactions with the syndecan core protein.


Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 772
Author(s):  
João Botelho ◽  
Vanessa Machado ◽  
José João Mendes ◽  
Paulo Mascarenhas

The latest evidence revealed a possible association between periodontitis and Parkinson’s disease (PD). We explored the causal relationship of this bidirectional association through two-sample Mendelian randomization (MR) in European ancestry populations. To this end, we used openly accessible data of genome-wide association studies (GWAS) on periodontitis and PD. As instrumental variables for periodontitis, seventeen single-nucleotide polymorphisms (SNPs) from a GWAS of periodontitis (1817 periodontitis cases vs. 2215 controls) and eight non-overlapping SNPs of periodontitis from an additional GWAS for validation purposes. Instrumental variables to explore for the reverse causation included forty-five SNPs from a GWAS of PD (20,184 cases and 397,324 controls). Multiple approaches of MR were carried-out. There was no evidence of genetic liability of periodontitis being associated with a higher risk of PD (B = −0.0003, Standard Error [SE] 0.0003, p = 0.26). The eight independent SNPs (B = −0.0000, SE 0.0001, p = 0.99) validated this outcome. We also found no association of genetically primed PD towards periodontitis (B = −0.0001, SE 0.0001, p = 0.19). These MR study findings do not support a bidirectional causal genetic liability between periodontitis and PD. Further GWAS studies are needed to confirm the consistency of these results.


2021 ◽  
Vol 14 (4) ◽  
pp. 287
Author(s):  
Courtney M. Vecera ◽  
Gabriel R. Fries ◽  
Lokesh R. Shahani ◽  
Jair C. Soares ◽  
Rodrigo Machado-Vieira

Despite being the most widely studied mood stabilizer, researchers have not confirmed a mechanism for lithium’s therapeutic efficacy in Bipolar Disorder (BD). Pharmacogenomic applications may be clinically useful in the future for identifying lithium-responsive patients and facilitating personalized treatment. Six genome-wide association studies (GWAS) reviewed here present evidence of genetic variations related to lithium responsivity and side effect expression. Variants were found on genes regulating the glutamate system, including GAD-like gene 1 (GADL1) and GRIA2 gene, a mutually-regulated target of lithium. In addition, single nucleotide polymorphisms (SNPs) discovered on SESTD1 may account for lithium’s exceptional ability to permeate cell membranes and mediate autoimmune and renal effects. Studies also corroborated the importance of epigenetics and stress regulation on lithium response, finding variants on long, non-coding RNA genes and associations between response and genetic loading for psychiatric comorbidities. Overall, the precision medicine model of stratifying patients based on phenotype seems to derive genotypic support of a separate clinical subtype of lithium-responsive BD. Results have yet to be expounded upon and should therefore be interpreted with caution.


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