bims-supasi 2022-03-27 papers

bims-supasi

Biomed News

on Sulfation pathways and signalling

Issue of 2022‒03‒27
fourteen papers selected by
Jonathan Wolf Mueller
University of Birmingham

GRASP depletion-mediated Golgi fragmentation impairs glycosaminoglycan synthesis, sulfation, and secretion.
The Interaction between Chondroitin Sulfate and Dermatan Sulfate Tetrasaccharides and Pleiotrophin.
The SARS-CoV-2 Entry Inhibition Mechanisms of Serine Protease Inhibitors, OM-85, Heparin and Soluble HS Might Be Linked to HS Attachment Sites.
Effects of heparan sulfate from porcine mucosa on Aβ1-42-induced neurotoxicity in vitro and in vivo.
Coreceptor Functions of Cell Surface Heparan Sulfate Proteoglycans.
The inhibition effects and mechanisms of sulfated chitooligosaccharides on influenza A virus in vitro and in vivo.
Autism, heparan sulfate and potential interventions.
On resin synthesis of sulfated oligosaccharides.
DHEA Protects Human Cholangiocytes and Hepatocytes against Apoptosis and Oxidative Stress.
Low molecular weight sulfated chitosan efficiently reduces infection capacity of porcine circovirus type 2 (PCV2) in PK15 cells.
3,4-Dicaffeoylquinic Acid from the Medicinal Plant Ilex kaushue Disrupts the Interaction Between the Five-Fold Axis of Enterovirus A-71 and the Heparan Sulfate Receptor.
Uremic toxin indoxyl sulfate induces dysfunction of vascular smooth muscle cells via integrin-β1/ERK signaling pathway.
Allosteric modulation of the chemokine receptor-chemokine CXCR4-CXCL12 complex by tyrosine sulfation.
Cholesterol Sulfate Exerts Protective Effect on Pancreatic β-Cells by Regulating β-Cell Mass and Insulin Secretion.

Cell Mol Life Sci. 2022 Mar 21. 79(4): 199

GRASP depletion-mediated Golgi fragmentation impairs glycosaminoglycan synthesis, sulfation, and secretion.

Erpan Ahat, Yuefan Song, Ke Xia, Whitney Reid, Jie Li, Sarah Bui, Fuming Zhang, Robert J Linhardt, Yanzhuang Wang.

  Synthesis of glycosaminoglycans, such as heparan sulfate (HS) and chondroitin sulfate (CS), occurs in the lumen of the Golgi, but the relationship between Golgi structural integrity and glycosaminoglycan synthesis is not clear. In this study, we disrupted the Golgi structure by knocking out GRASP55 and GRASP65 and determined its effect on the synthesis, sulfation, and secretion of HS and CS. We found that GRASP depletion increased HS synthesis while decreasing CS synthesis in cells, altered HS and CS sulfation, and reduced both HS and CS secretion. Using proteomics, RNA-seq and biochemical approaches, we identified EXTL3, a key enzyme in the HS synthesis pathway, whose level is upregulated in GRASP knockout cells; while GalNAcT1, an essential CS synthesis enzyme, is robustly reduced. In addition, we found that GRASP depletion decreased HS sulfation via the reduction of PAPSS2, a bifunctional enzyme in HS sulfation. Our study provides the first evidence that Golgi structural defect may significantly alter the synthesis and secretion of glycosaminoglycans.

Keywords:  Chondroitin sulfate (CS); GRASP55; GRASP65; Golgi; Heparan sulfate (HS); Proteomic; RNAseq; Sulfation; Synthesis

DOI:  https://doi.org/10.1007/s00018-022-04223-3
Int J Mol Sci. 2022 Mar 11. pii: 3026. [Epub ahead of print]23(6):

The Interaction between Chondroitin Sulfate and Dermatan Sulfate Tetrasaccharides and Pleiotrophin.

María Jose García-Jiménez, Myriam Torres-Rico, José L de Paz, Pedro M Nieto.

  Pleiotrophin (PTN) is a neurotrophic factor that participates in the development of the embryonic central nervous system (CNS) and neural stem cell regulation by means of an interaction with sulfated glycosaminoglycans (GAGs). Chondroitin sulfate (CS) is the natural ligand in the CNS. We have previously studied the complexes between the tetrasaccharides used here and MK (Midkine) by ligand-observed NMR techniques. The present work describes the interactions between a tetrasaccharide library of synthetic models of CS-types and mimetics thereof with PTN using the same NMR transient techniques. We have concluded that: (1) global ligand structures do not change upon binding, (2) the introduction of lipophilic substituents in the structure of the ligand improves the strength of binding, (3) binding is weaker than for MK, (4) STD-NMR results are compatible with multiple binding modes, and (5) the replacement of GlcA for IdoA is not relevant for binding. Then we can conclude that the binding of CS derivatives to PTN and MK are similar and compatible with multiple binding modes of the same basic conformation.

Keywords:  GAG synthesis; STD-NMR spectroscopy; carbohydrate–protein interaction; chondroitin sulfate; pleiotrophin; transient NMR methods

DOI:  https://doi.org/10.3390/ijms23063026
Molecules. 2022 Mar 17. pii: 1947. [Epub ahead of print]27(6):

The SARS-CoV-2 Entry Inhibition Mechanisms of Serine Protease Inhibitors, OM-85, Heparin and Soluble HS Might Be Linked to HS Attachment Sites.

Antony Cheudjeu.

  This article discusses the importance of D-xylose for fighting viruses (especially SARS-CoV-2) that use core proteins as receptors at the cell surface, by providing additional supporting facts that these viruses probably bind at HS/CS attachment sites (i.e., the hydroxyl groups of Ser/Thr residues of the core proteins intended to receive the D-xylose molecules to initiate the HS/CS chains). Essentially, the additional supporting facts, are: some anterior studies on the binding sites of exogenous heparin and soluble HS on the core proteins, the inhibition of the viral entry by pre-incubation of cells with heparin, and additionally, corroborating studies about the mechanism leading to type 2 diabetes during viral infection. We then discuss the mechanism by which serine protease inhibitors inhibit SARS-CoV-2 entry. The biosynthesis of heparan sulfate (HS), chondroitin sulfate (CS), dermatan sulfate (DS), and heparin (Hep) is initiated not only by D-xylose derived from uridine diphosphate (UDP)-xylose, but also bioactive D-xylose molecules, even in situations where cells were previously treated with GAG inhibitors. This property of D-xylose shown by previous anterior studies helped in the explanation of the mechanism leading to type 2 diabetes during SARS-CoV-2 infection. This explanation is completed here by a preliminary estimation of xyloside GAGs (HS/CS/DS/Hep) in the body, and with other previous studies helping to corroborate the mechanism by which the D-xylose exhibits its antiglycaemic properties and the mechanism leading to type 2 diabetes during SARS-CoV-2 infection. This paper also discusses the confirmatory studies of regarding the correlation between D-xylose and COVID-19 severity.

Keywords:  COVID-19; D-xylose; alpha-1-antitrypsin; camostat mesylate; competitive inhibition; nafamostat mesylate; serine protease inhibitor; type 2 diabetes; viral infection

DOI:  https://doi.org/10.3390/molecules27061947
Int J Biol Macromol. 2022 Mar 17. pii: S0141-8130(22)00549-9. [Epub ahead of print]206 823-836

Effects of heparan sulfate from porcine mucosa on Aβ1-42-induced neurotoxicity in vitro and in vivo.

Lidan Wu, Na Zhao, Wenjie Jiang, Fengshan Wang.

  Amyloid-β (Aβ) deposition and neurotoxicity play an important role in Alzheimer's disease (AD). Notably, the nonnegligible role of endogenous heparan sulfate (HS) in the release, uptake and misfolding of Aβ sheds light on the discovery of HS as an effective drug for AD. In this work, the effects of HS from porcine mucosa (PMHS) on Aβ1-42-induced neurotoxicity were investigated both in vitro and in vivo. The in vitro AD model was established in SH-SY5Y via treatment with oligomeric Aβ1-42, and the in vivo AD model was established by intracerebroventricular injection of Aβ1-42 to KM mice. The results showed that in vitro, PMHS could ameliorate the inflammation and apoptosis response of SH-SY5Y cells induced by Aβ1-42; in vivo, PMHS could not only improve the cognitive impairment induced by Aβ1-42 but also inhibit neuroinflammation and apoptosis in the brain. Furthermore, PMHS lowered the levels of Aβ1-42 in the peripheral circulation and brain by improving the phagocytosis function of neutrophils. This is the first report that PMHS enhances the phagocytosis function of neutrophils to alleviate Aβ-induced neurotoxicity. Moreover, our work verified the feasibility of peripheral Aβ clearance for improving neurotoxicity. Conclusively, we believe that PMHS could be developed into neuroprotective drugs for AD.

Keywords:  Amyloid-β oligomers; Heparan sulfate; Neurotoxicity

DOI:  https://doi.org/10.1016/j.ijbiomac.2022.03.079
Am J Physiol Cell Physiol. 2022 Mar 23.

Coreceptor Functions of Cell Surface Heparan Sulfate Proteoglycans.

Kazutaka Hayashida, Rafael S Aquino, Pyong Woo Park.

  Receptor-ligand interactions play an important role in many biological processes by triggering specific cellular responses. These interactions are frequently regulated by coreceptors that facilitate, alter, or inhibit signaling. Coreceptors work in parallel with other specific and accessory molecules to coordinate receptor-ligand interactions. Cell surface heparan sulfate proteoglycans (HSPGs) function as unique coreceptors because they can bind to many ligands and receptors through their HS and core protein motifs. Cell surface HSPGs are typically expressed in abundance of the signaling receptors and, thus, are capable of mediating the initial binding of ligands to the cell surface. HSPG coreceptors do not possess kinase domains or intrinsic enzyme activities and, for the most part, binding to cell surface HSPGs does not directly stimulate intracellular signaling. Because of these features, cell surface HSPGs primarily function as coreceptors for many receptor-ligand interactions. Given that cell surface HSPGs are widely conserved, they likely serve fundamental functions to preserve basic physiological processes. Indeed, cell surface HSPGs can support specific cellular interactions with growth factors, morphogens, chemokines, extracellular matrix (ECM) components, and microbial pathogens and their secreted virulence factors. Through these interactions, HSPG coreceptors regulate cell adhesion, proliferation, migration and differentiation, and impact the onset, progression, and outcome of pathophysiological processes, such as development, tissue repair, inflammation, infection, and tumorigenesis. This review seeks to provide an overview of the various mechanisms of how cell surface HSPGs function as coreceptors.

Keywords:  coreceptor; extracellular matrix; heparan sulfate; proteoglycan; signaling

DOI:  https://doi.org/10.1152/ajpcell.00050.2022
Carbohydr Polym. 2022 Jun 15. pii: S0144-8617(22)00220-X. [Epub ahead of print]286 119316

The inhibition effects and mechanisms of sulfated chitooligosaccharides on influenza A virus in vitro and in vivo.

Shixin Wang, Yanan Luo, Lianghao Huang, Shuyao Wang, Cui Hao, Lishan Sun, Yang Zhang, Wei Wang, Chunxia Li.

  Sulfated chitooligosaccharide was reported to possess inhibition effect on human immunodeficiency virus (HIV) entry into host cells. Herein, we prepared chitooligosaccharide COS and its sulfate derivative SCOS and explored whether the sulfation modification can enhance the anti-influenza A virus (IAV) activity of COS. Interestingly, we discovered that SCOS possessed broad-spectrum anti-IAV effects with low toxicity, while the non-sulfated chitooligosaccharide COS had very low inhibition on IAV, verifying that the sulfation modification is essential for the anti-IAV actions of chitooligosaccharide. SCOS may target virus hemagglutinin (HA) protein to block both virus adsorption and membrane fusion processes. Oral administration of SCOS significantly decreased pulmonary viral titers and improved survival rate in IAV infected mice, comparable to the effects of Oseltamivir. Therefore, our findings support further studies on the use of SCOS as a novel entry inhibitor for IAV and as a supplement to current therapeutics for influenza.

Keywords:  3′-SL (CID: 123914); Acetone (CID: 180); Adsorption; Dimethylformamide (CID: 6228); Eosin (CID: 11048); Glutaraldehyde (CID: 3485); HA protein; Hematoxylin (CID: 442514); Influenza A virus; MUNANA (CID: 122174046); Membrane fusion; Oseltamivir (CID: 65028); Paraformaldehyde (CID: 712); Sulfated chitooligosaccharide; l-Glutamine (CID: 5961)

DOI:  https://doi.org/10.1016/j.carbpol.2022.119316
Exp Neurol. 2022 Mar 17. pii: S0014-4886(22)00075-9. [Epub ahead of print] 114050

Autism, heparan sulfate and potential interventions.

Jacob Alexander, Gizem Keles, Jessica Killingsworth, Ronald Bronson, Christine Perez, Darrell Sawmiller, R Douglas Shytle.

  Developmental disabilities are defined as disorders that result in the limitation of function due to impaired development of the nervous system; these disabilities can be present in the form of impairments in learning, language, behavior, or physical abilities. Examples of developmental disorders include attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), cerebral palsy (CP), hearing loss, blindness, intellectual disability, and learning disability. Of these disorders, ASD prevalence was 18.5 per 1000 children (1 in 54) aged 8 in 2016. Current literature suggests that deficient levels of heparan sulfate (HS), an acidic and linear glycosaminoglycan (GAG), is likely causative of ASD. The cascading effect of deficient HS levels can offer compelling evidence for the association of HS with ASD. Deficient levels of HS lead to defective Slit/Robo signaling, which affects axonal guidance and dendritic spine formation. Defective Slit/Robo signaling leads to increased Arp2/3 activity and dendritic spine density, which has been observed in the brains of persons with ASD. Therefore, interventions that target HS and its associated pathways may be viable treatment options for ASD.

Keywords:  Arp2/3; Autism spectrum disorders; Dendritic spines; Heparan sulfate; Heparan sulfate mimetics; Neuroinflammation; Slit/Robo; WASP

DOI:  https://doi.org/10.1016/j.expneurol.2022.114050
Chem Sci. 2022 Feb 16. 13(7): 2115-2120

On resin synthesis of sulfated oligosaccharides.

Theodore Tyrikos-Ergas, Eric T Sletten, Jhih-Yi Huang, Peter H Seeberger, Martina Delbianco.

Sulfated glycans are involved in many biological processes, making well-defined sulfated oligosaccharides highly sought molecular probes. These compounds are a considerable synthetic challenge, with each oligosaccharide target requiring specific synthetic protocols and extensive purifications steps. Here, we describe a general on resin approach that simplifies the synthesis of sulfated glycans. The oligosaccharide backbone, obtained by Automated Glycan Assembly (AGA), is subjected to regioselective sulfation and hydrolysis of protecting groups. The protocol is compatible with several monosaccharides and allows for multi-sulfation of linear and branched glycans. Seven diverse, biologically relevant sulfated glycans were prepared in good to excellent overall yield.

DOI: https://doi.org/10.1039/d1sc06063e
Cells. 2022 Mar 18. pii: 1038. [Epub ahead of print]11(6):

DHEA Protects Human Cholangiocytes and Hepatocytes against Apoptosis and Oxidative Stress.

Ewa Kilanczyk, Dagmara Ruminkiewicz, Jesus M Banales, Piotr Milkiewicz, Małgorzata Milkiewicz.

  Primary biliary cholangitis (PBC) is a rare chronic cholestatic and immune-mediated liver disease of unknown aetiology that targets intrahepatic bile duct cells (cholangiocytes) and primarily affects postmenopausal women, when their estrogen levels sharply decrease. An impaired cholangiocyte response to estrogen characterizes the terminal stage of the disease, as this is when an inefficiency of cholangiocyte proliferation, in balancing the loss of intrahepatic bile ducts, is observed. Here, we report that the estrogen precursor dehydroepiandrosterone (DHEA) and its sulfate metabolites, DHEA-S and 17 β-estradiol, enhance the proliferation of cholangiocytes and hepatocytes in vitro. Flow cytometry analysis showed that DHEA and DHEA-S decreased glyco-chenodeoxycholic acid (GCDC)-driven apoptosis in cholangiocytes. Cell viability assay (MTT) indicated that ER-α, -β, and the G-protein-coupled estrogen receptor, are involved in the protection of DHEA against oxidative stress in cholangiocytes. Finally, immunoblot analysis showed an elevated level of steroid sulfatase and a reduced level of sulfotransferase 1E1 enzymes, involved in the desulfation/sulfation process of estrogens in cirrhotic PBC, and primary sclerosis cholangitis (PSC) liver tissues, another type of chronic cholestatic and immune-mediated liver disease. Taken together, these results suggest that DHEA can prevent the deleterious effects of certain potentially toxic bile acids and reactive oxygen species, delaying the onset of liver disease.

Keywords:  DHEA; apoptosis; cholangiocytes

DOI:  https://doi.org/10.3390/cells11061038
Virol J. 2022 Mar 24. 19(1): 52

Low molecular weight sulfated chitosan efficiently reduces infection capacity of porcine circovirus type 2 (PCV2) in PK15 cells.

Daniela Jiménez-Arriagada, Alejandro A Hidalgo, Victor Neira, Andrónico Neira-Carrillo, Sergio A Bucarey.

  BACKGROUND: Porcine circovirus type 2 (PCV2)-associated diseases are a major problem for the swine industry worldwide. In addition to vaccines, the availability of antiviral polymers provides an efficient and safe option for reducing the impact of these diseases. By virtue of their molecular weight and repetitious structure, polymers possess properties not found in small-molecule drugs. In this perspective, we focus on chitosan, a ubiquitous biopolymer, that adjusts the molecular weight and sulfated-mediated functionality can act as an efficient antiviral polymer by mimicking PCV2-cell receptor interactions.METHODS: Sulfated chitosan (Chi-S) polymers of two molecular weights were synthesized and characterized by FTIR, SEM-EDS and elemental analysis. The Chi-S solutions were tested against PCV2 infection in PK15 cells in vitro and antiviral activity was evaluated by measuring the PCV2 DNA copy number, TCID50 and capsid protein expression, upon application of different molecular weights, sulfate functionalization, and concentrations of polymer. In addition, to explore the mode of action of the Chi-S against PCV2 infection, experiments were designed to elucidate whether the antiviral activity of the Chi-S would be influenced by when it was added to the cells, relative to the time and stage of viral infection.
RESULTS: Chi-S significantly reduced genomic copies, TCID50 titers and capsid protein of PCV2, showing specific antiviral effects depending on its molecular weight, concentration, and chemical functionalization. Assays designed to explore the mode of action of the low molecular weight Chi-S revealed that it exerted antiviral activity through impeding viral attachment and penetration into cells.
CONCLUSIONS: These findings help better understanding the interactions of PCV2 and porcine cells and reinforce the idea that sulfated polymers, such as Chi-S, represent a promising candidates for use in antiviral therapies against PCV2-associated diseases. Further studies in swine are warranted.

Keywords:  Antiviral polymers; Cell attachment; Chitosan; PK15 cells; Porcine circovirus type 2; Sulfated chitosan

DOI:  https://doi.org/10.1186/s12985-022-01781-7
J Virol. 2022 Mar 23. e0054221

3,4-Dicaffeoylquinic Acid from the Medicinal Plant Ilex kaushue Disrupts the Interaction Between the Five-Fold Axis of Enterovirus A-71 and the Heparan Sulfate Receptor.

Chung-Fan Hsieh, Yu-Li Chen, Guan-Hua Lin, Yoke Fun Chan, Pei-Wen Hsieh, Jim-Tong Horng.

  While infections by enterovirus A71 (EV-A71) are generally self-limiting, they can occasionally lead to serious neurological complications and death. No licensed therapies against EV-A71 currently exist. Using anti-virus-induced cytopathic effect assays, 3,4-dicaffeoylquinic acid (3,4-DCQA) from Ilex kaushue extracts was found to exert significant anti-EV-A71 activity, with a broad inhibitory spectrum against different EV-A71 genotypes. Time-of-drug-addition assays revealed that 3,4-DCQA affects the initial phase (entry step) of EV-A71 infection by directly targeting viral particles and disrupting viral attachment to host cells. Using resistant virus selection experiments, we found that 3,4-DCQA targets the glutamic acid residue at position 98 (E98) and the proline residue at position 246 (P246) in the 5-fold axis located within the VP1 structural protein. Recombinant viruses harboring the two mutations were resistant to 3,4-DCQA-elicited inhibition of virus attachment and penetration into human rhabdomyosarcoma (RD) cells. Finally, we showed that 3,4-DCQA specifically inhibited the attachment of EV-A71 to the host receptor heparan sulfate (HS), but not to the scavenger receptor class B member 2 (SCARB2) and P-selectin glycoprotein ligand-1 (PSGL1). Molecular docking analysis confirmed that 3,4-DCQA targets the 5-fold axis to form a stable structure with the E98 and P246 residues through noncovalent and van der Waals interactions. The targeting of E98 and P246 by 3,4-DCQA was found to be specific; accordingly, HS binding of viruses carrying the K242A or K244A mutations in the 5-fold axis was successfully inhibited by 3,4-DCQA.The clinical utility of 3,4-DCQA in the prevention or treatment of EV-A71 infections warrants further scrutiny. IMPORTANCE The canyon region and the 5-fold axis of the EV-A71 viral particle located within the VP1 protein mediate the interaction of the virus with host surface receptors. The three most extensively investigated cellular receptors for EV-A71 include SCARB2, PSGL1, and cell surface heparan sulfate. In the current study, a RD cell-based anti-cytopathic effect assay was used to investigate the potential broad spectrum inhibitory activity of 3,4-DCQA against different EV-A71 strains. Mechanistically, we demonstrate that 3,4-DCQA disrupts the interaction between the 5-fold axis of EV-A71 and its heparan sulfate receptor; however, no effect was seen on the SCARB2 or PSGL1 receptors. Taken together, our findings show that this natural product may pave the way to novel anti-EV-A71 therapeutic strategies.

Keywords:  3; 4-dicaffeoylquinic acid; 5-fold axis; enterovirus-A71; heparan sulphate

DOI:  https://doi.org/10.1128/jvi.00542-21
Clin Exp Nephrol. 2022 Mar 25.

Uremic toxin indoxyl sulfate induces dysfunction of vascular smooth muscle cells via integrin-β1/ERK signaling pathway.

Haibo Yu, Chunyu Zhou, Dayong Hu, Changbin Li, Qiang Wang, Wen Xue, Ai Peng.

  BACKGROUND: Protein-bound uremic toxins (PBUTs) are reported to be one of the major culprits in chronic kidney disease-cardiovascular disease (CKD-CVD) development, yet its mechanism is not fully clear. Our previous study confirmed elevated expression of integrin-β1 (ITGβ1) in vascular smooth muscle cells of uremic patients. Thus, this study aimed to explore the relationship between PBUTs and ITGβ1 in uremic vasculature injury.METHODS: Human umbilical vein smooth muscle cells (HUVSMCs) and endothelial cells (HUVECs) were treated with two representative PUBTs, indoxyl sulfate (IS) and p-cresyl sulfate (PC). Both cells were measured for the expression of ITGβ1 and downstream signaling pathways and assayed for proliferation, migration, adhesion and apoptosis.
RESULTS: The IS treatments were observed with significantly up-regulated ITGβ1 in HUVSMCs but not in HUVECs, while PC did not induce ITGβ1 alteration in either HUVSMCs or HUVECs. Furthermore, overexpression of ITGβ1 revealed activated downstream signal-regulated kinase (ERK) signaling pathway with promoted focal adhesion, migration, proliferation but no apoptosis in HUVSMCs by IS. These functional and pathway alterations could be significantly suppressed by RNA interference of ITGβ1. More importantly, the application of ERK1/2 inhibitor significantly suppressed the focal adhesion, migration and proliferation of HUVSMCs.
CONCLUSION: We first demonstrated that ITGβ1/ERK signaling pathway mediated abnormal focal adhesion, migration and proliferation of vascular smooth muscle cells stimulated by IS. ITGβ1/ERK signaling may serve as a novel therapeutic target for CKD-CVD.

Keywords:  Extracellular signal-regulated kinase; Indoxyl sulfate; Integrin-β1; Protein-bound uremic toxins; Smooth muscle cells

DOI:  https://doi.org/10.1007/s10157-022-02195-z
Int J Biol Macromol. 2022 Mar 17. pii: S0141-8130(22)00548-7. [Epub ahead of print]206 812-822

Allosteric modulation of the chemokine receptor-chemokine CXCR4-CXCL12 complex by tyrosine sulfation.

Archana Sonawani, Shalmali Kharche, Debjani Dasgupta, Durba Sengupta.

  The chemokine receptor CXCR4 and its cognate ligand CXCL12 mediate pathways that lead to cell migration and chemotaxis. Although the structural details of related receptor-ligand complexes have been resolved, the roles of the N-terminal domain of the receptor and post-translational sulfation that are determinants of ligand selectivity and affinity remain unclear. Here, we analyze the structural dynamics induced by receptor sulfation by combining molecular dynamics, docking and network analysis. The sulfotyrosine residues, 7YsN-term, 12YsN-term and 21YsN-term allow the N-terminal domain of the apo-sulfated receptor to adopt an "open" conformation that appears to facilitate ligand binding. The overall topology of the CXCR4-CXCL12 complex is independent of the sulfation state, but an extensive network of protein-protein interactions characterizes the sulfated receptor, in line with its increased ligand affinity. The altered interactions of sulfotyrosine residues, such as 21YsN-term-47RCXCL12 replacing the 21YN-term-13FCXCL12 interaction, propagate via allosteric pathways towards the receptor lumen. In particular, our results suggest that the experimentally-reported receptor-ligand interactions 262D6.58-8RCXCL12 and 277E7.28-12RCXCL12 could be dependent on the sulfation state of the receptor and need to be carefully analyzed. Our work is an important step in understanding chemokine-receptor interactions and how post-translational modifications could modulate receptor-ligand complexes.

Keywords:  Allosteric communication pathway; Atomistic molecular dynamics simulations; G protein-coupled receptor; Ligand binding; Post-translational modification; Protein-protein interface

DOI:  https://doi.org/10.1016/j.ijbiomac.2022.03.078
Front Pharmacol. 2022 ;13 840406

Cholesterol Sulfate Exerts Protective Effect on Pancreatic β-Cells by Regulating β-Cell Mass and Insulin Secretion.

Xueping Zhang, Dan Deng, Daxin Cui, Yin Liu, Siyuan He, Hongmei Zhang, Yaorui Xie, Xiaoqian Yu, Shanshan Yang, Yulong Chen, Zhiguang Su.

  Rational: Cholesterol sulfate (CS) is the most abundant known sterol sulfate in human plasma, and it plays a significant role in the control of metabolism and inflammatory response, which contribute to the pathogenesis of insulin resistance, β-cell dysfunction and the resultant development of diabetes. However, the role of CS in β-cells and its effect on the development of diabetes remain unknown. Here, we determined the physiological function of CS in pancreatic β-cell homeostasis. Materials and Methods: Blood CS levels in streptozotocin (STZ)- or high-fat diet-induced diabetic mice and patients with type 1 or 2 diabetes were determined by LC-MS/MS. The impact of CS on β-cell mass and insulin secretion was investigated in vitro in isolated mouse islets and the β-cell line INS-1 and in vivo in STZ-induced diabetic mice. The molecular mechanism of CS was explored by viability assay, EdU incorporation analysis, flow cytometry, intracellular Ca2+ influx analysis, mitochondrial membrane potential and cellular ROS assays, and metabolism assay kits. Results: Plasma CS levels in mice and humans were significantly elevated under diabetic conditions. CS attenuated diabetes in a low-dose STZ-induced mouse model. Mechanistically, CS promoted β-cell proliferation and protected β-cells against apoptosis under stressful conditions, which in turn preserved β-cell mass. In addition, CS supported glucose transporter-2 (GLUT2) expression and mitochondrial integrity, which then resulted in a less reactive oxygen species (ROS) generation and an increase in ATP production, thereby enabling insulin secretion machinery in the islets to function adequately. Conclusion: This study revealed a novel dual role of CS in integrating β-cell survival and cell function, suggesting that CS might offer a physiologic approach to preserve β-cells and protect against the development of diabetes mellitus.

Keywords:  apoptosis; cholesterol sulfate; diabetes; mitochondria; pancreatic β-cells; proliferation; reactive oxygen species

DOI:  https://doi.org/10.3389/fphar.2022.840406