Heparin Oligosaccharides Inhibit Chemokine (CXC Motif) Ligand 12 (CXCL12) Cardioprotection by Binding Orthogonal to the Dimerization Interface, Promoting Oligomerization, and Competing with the Chemokine (CXC Motif) Receptor 4 (CXCR4) N Terminus

Ziarek, Joshua J.; Veldkamp, Christopher T.; Zhang, Fuming; Murray, Nathan J.; Kartz, Gabriella A.; Liang, Xinmiao; Su, Jidong; Baker, John E.; Linhardt, Robert J.; Volkman, Brian F.

doi:10.1074/jbc.m112.394064

Cited by 73 publications

(93 citation statements)

References 44 publications

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“…We used the hCXCL1 dimer (PDB code 1MGS) and heparin 12-mer (PDB code 1HPN) structures to generate the HADDOCK models. a similar observation of competition between N-domain and GAG binding and proteolytic protection in the GAG-bound form has been reported (41).…”

Section: Discussionsupporting

confidence: 57%

“…X-ray structures could be determined only of a disaccharide-bound chemokine (38,39). Although NMR characterization of binding of disaccharides posed no problems, characterizing longer oligosaccharides seems to depend on the chemokine, with some giving good spectra and others precipitating even for a tetrasaccharide (26,32,40,41). We obtained excellent NMR spectra for hCXCL1, and, more significantly, our observation of two distinct non-overlapping GAG binding domains is novel.…”

Section: Discussionmentioning

confidence: 51%

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CXCL1/MGSA Is a Novel Glycosaminoglycan (GAG)-binding Chemokine

Sepuru

Rajarathnam

2016

Journal of Biological Chemistry

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In humans, the chemokine CXCL1/MGSA (hCXCL1) plays fundamental and diverse roles in pathophysiology, from microbial killing to cancer progression, by orchestrating the directed migration of immune and non-immune cells. Cellular trafficking is highly regulated and requires concentration gradients that are achieved by interactions with sulfated glycosaminoglycans (GAGs). However, very little is known regarding the structural basis underlying hCXCL1-GAG interactions. We addressed this by characterizing the binding of GAG heparin oligosaccharides to hCXCL1 using NMR spectroscopy. Binding experiments under conditions at which hCXCL1 exists as monomers and dimers indicate that the dimer is the high-affinity GAG ligand. NMR experiments and modeling studies indicate that lysine and arginine residues mediate binding and that they are located in two non-overlapping domains. One domain, consisting of N-loop and C-helical residues (defined as ␣-domain) has also been identified previously as the GAG-binding domain for the related chemokine CXCL8/IL-8. The second domain, consisting of residues from the N terminus, 40s turn, and third ␤-strand (defined as ␤-domain) is novel. Eliminating ␤-domain binding by mutagenesis does not perturb ␣-domain binding, indicating two independent GAG-binding sites. It is known that N-loop and N-terminal residues mediate receptor activation, and we show that these residues are also involved in extensive GAG interactions. We also show that the GAG-bound hCXCL1 completely occlude receptor binding. We conclude that hCXCL1-GAG interactions provide stringent control over regulating chemokine levels and receptor accessibility and activation, and that chemotactic gradients mediate cellular trafficking to the target site.Chemokines, a large family of small soluble proteins, are highly versatile and play fundamental roles in diverse functions, from combating infection and initiating tissue repair to regulating metabolism and organ development (1, 2). Common to these various functions is the directed movement of various cell types to distal and remote locations. Cellular trafficking must be highly coordinated to elicit the required biological function, and its dysregulation could be detrimental, resulting in disease. There is now increasing evidence that the ability of a chemokine to reversibly exist as monomers and dimers and binding glycosaminoglycans is coupled and plays important roles in mediating these functions (3, 4).Glycosaminoglycans (GAGs) 2 such as heparan sulfate (HS) are highly sulfated polysaccharides. They are expressed ubiquitously by many cell types, are anchored to the cell surface by covalent attachment to membrane proteins, and form non-covalent complexes with proteins in the extracellular matrix (5-7). Animal models and cellular studies have established that GAG interactions dictate chemokine concentration gradients and that these gradients orchestrate cellular trafficking (8 -10). GAGs are acidic, and chemokines are basic or contain clusters of basic residues, indicating that electr...

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Section: Discussionsupporting

confidence: 57%

Section: Discussionmentioning

confidence: 51%

CXCL1/MGSA Is a Novel Glycosaminoglycan (GAG)-binding Chemokine

Sepuru

Rajarathnam

2016

Journal of Biological Chemistry

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“…2A and 7C). It has also been shown that GAG binding increases the lifetime of CXCL12 by protecting it from enzymatic cleavage (31,62). These observations suggest that NAC monomer-dimer equilibrium and GAG binding interactions and affinities must be highly regulated and that any disruption, such as proteolytic cleavage, impairs dimerization and GAG binding, which, in turn, disrupts chemokine gradient and neutrophil recruitment, enabling microbes to evade the host immune response.…”

Section: Discussionmentioning

confidence: 99%

“…Two x-ray structures of chemokine-disaccharide are known, and most NMR structural studies also report only disaccharide binding, which provides only limited insights (46,47). However, NMR studies have had better success with longer GAGs, but the extent of the structural insights varies among different chemokines and seems to be critically dependent on experimental conditions (21,31,48). Recent studies by Handel and co-workers (21) on CCL27 and Volkman and co-workers (31) on CXCL12 using different oligosaccharides, protein concentrations, protein:GAG ratios, and variants (monomer and dimer) have shown that chemokine structural plasticity, oligomerization properties, GAG length, and binding-induced oligomerization/aggregation/precipitation are intimately coupled.…”

Section: Discussionmentioning

confidence: 99%

Molecular Basis of Glycosaminoglycan Heparin Binding to the Chemokine CXCL1 Dimer

Poluri

Joseph

Sawant³

et al. 2013

Journal of Biological Chemistry

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Background: Glycosaminoglycan (GAG)-chemokine dimer interactions regulate neutrophil trafficking, but the molecular basis underlying their interactions is not well understood. Results: NMR studies of murine CXCL1 indicate that heparin spans the dimer interface and enhances its structural integrity and stability. Conclusion: Heparin binding modulates multiple structural properties of the chemokine dimer. Significance: This study provides novel structural insights into how chemokine dimers orchestrate neutrophil recruitment.

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“…In addition, application of N-terminally truncated CXCL12 variants induced HPC mobilization, with CXCL12 and CXCL12 demonstrating a significant effect on HPC mobilization. In addition to the putative antagonistic mechanism for CXCL12 as mentioned earlier, competition with biologically active CXCL12 for binding to GAG chains of proteoglycans along the endothelial surface might be responsible for the mobilization of HPCs [7,54]. The excess of N-terminally processed CXC12, although demonstrating a reduced affinity for Heparin, would be sufficient for a relevant displacement of active CXCL12.…”

Section: Discussionmentioning

confidence: 99%

Identification and Characterization of Circulating Variants of CXCL12 from Human Plasma: Effects on Chemotaxis and Mobilization of Hematopoietic Stem and Progenitor Cells

Richter

Jochheim-Richter

Ciuculescu

et al. 2014

Stem Cells and Development

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Mobilization of hematopoietic stem and progenitor cells (HPCs) is induced by treatment with granulocytecolony stimulating factor, chemotherapy, or irradiation. We observed that these treatments are accompanied by a release of chemotactic activity into the blood. This plasma activity is derived from the bone marrow, liver, and spleen and acts on HPCs via the chemokine receptor CXCR4. A human blood peptide library was used to characterize CXCR4-activating compounds. We identified CXCL12 or CXCL12 induced a significant mobilization of HPCs in mice. Our findings indicate that plasma-derived CXCL12 variants may contribute to the regulation of HPC mobilization by modulating the binding of CXCL12 to GAGs rather than blocking the CXCR4 receptor and, therefore, may have a contributing role in HPC mobilization.

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Heparin Oligosaccharides Inhibit Chemokine (CXC Motif) Ligand 12 (CXCL12) Cardioprotection by Binding Orthogonal to the Dimerization Interface, Promoting Oligomerization, and Competing with the Chemokine (CXC Motif) Receptor 4 (CXCR4) N Terminus

Cited by 73 publications

References 44 publications

CXCL1/MGSA Is a Novel Glycosaminoglycan (GAG)-binding Chemokine

CXCL1/MGSA Is a Novel Glycosaminoglycan (GAG)-binding Chemokine

Molecular Basis of Glycosaminoglycan Heparin Binding to the Chemokine CXCL1 Dimer

Identification and Characterization of Circulating Variants of CXCL12 from Human Plasma: Effects on Chemotaxis and Mobilization of Hematopoietic Stem and Progenitor Cells

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