bims-supasi Biomed News
on Sulfation pathways and signalling
Issue of 2024‒01‒07
nine papers selected by
Jonathan Wolf Mueller, University of Birmingham

  1. Glycobiology. 2024 Jan 05. pii: cwae001. [Epub ahead of print]
      Heparan sulfate (HS) plays its biological functions by interacting with hundreds of secreted extracellular and transmembrane proteins. Interaction with HS has been shown to be required for the normal function of many HS-binding proteins. Receptor for advanced glycation end-product (RAGE) is such a protein, whose activation requires HS-induced oligomerization. Using RAGE as an exemplary protein, we show here the workflow of a simple method of developing and characterizing mAbs that targets the HS-binding site. We found that HS-binding site of RAGE is quite immunogenic as 18 out of 94 anti-RAGE mAbs target various epitopes within the HS-binding site. Sequence analysis found that a common feature of anti-HS-binding site mAbs is the presence of abundant acidic residues (range between 6 to 11) in the complementarity determining region, suggesting electrostatic interaction plays an important role in promoting antigen-antibody interaction. Interestingly, mAbs targeting different epitopes within the HS-binding site blocks HS-RAGE interaction to different degrees, and the inhibitory effect is highly consistent among mAbs that target the same epitope. Functional assay revealed that anti-HS-binding site mAbs show different potency in inhibiting osteoclastogenesis, and the inhibitory potency does not have a simple correlation with the affinity and the epitope. Our study demonstrates that developing HS-binding site targeting mAbs should be applicable to most HS-binding proteins. By targeting this unique functional site, these mAbs might find therapeutic applications in treating various human diseases.
    Keywords:  antibody; heparan sulfate-binding protein; osteoclastogenesis; receptor for advanced glycation end-product
  2. Carbohydr Polym. 2024 Mar 01. pii: S0144-8617(23)01148-7. [Epub ahead of print]327 121683
      Inflammatory cell infiltration, particularly macrophages, plays a major contribution to the pathogenesis of Rheumatoid Arthritis (RA). Exploiting the overexpression of folate receptors (FR-β) on these recruited macrophages has gained significant attraction for ligand-targeted delivery. Leflunomide (LEF), being an immunomodulatory agent is considered the cornerstone of the therapy, however, its oral efficacy is impeded by low solubility and escalating adverse effects profile. Therefore, in the present work, we developed Folate-conjugated chitosan-chondroitin sulfate nanoparticles encapsulating LEF for selective targeting at inflammatory sites in RA. For this purpose, the folate group was first conjugated with the chitosan polymer. After which, Folate Leflunomide Nanoparticles (FA-LEF-NPs) were synthesized through the ionotropic gelation method by employing FA-CHI and CHS. The polymers CHI and CHS were also presented with innate anti-inflammatory and anti-rheumatic attributes that were helpful in provision of synergistic effects to the formulation. These nanoparticles were further fabricated into a hydrogel, employing almond oil (A.O) as a permeation enhancer. The in vivo studies justified the preferential accumulation of FA-conjugated nanoparticles at inflamed joints more than any other organ in comparison to the free LEF and LEF-NPs formulation. The FA-LEF-NPs loaded hydrogel also ascertained a minimal adverse effect profile with an improvement of inflammatory cytokines expression.
    Keywords:  Chitosan; Chondroitin sulfate; Folic acid; Hydrogel; Leflunomide; Rheumatoid arthritis
  3. Sci Rep. 2024 01 02. 14(1): 292
      The chemokine receptor CCR5 is known to exist in cell surface subpopulations that differ in their capacity to engage ligands. One proposed explanation for this phenomenon is the presence of CCR5 species with different levels of post-translational modifications (PTMs). Tyrosine sulfation and O-glycan sialylation are PTMs that add negative charges to the extracellular domain of CCR5 and make strong contributions to chemokine binding but it is not known whether cellular mechanisms to control their levels exist. In this study we used a combination of sulfation-sensitive and sulfation-insensitive CCR5 ligands to show that the rate of turnover of CCR5 tyrosine sulfation is more rapid than the rate of turnover of the receptor itself. This suggests that the steady state level of CCR5 sulfation is maintained through the combination of tyrosine protein sulfotransferase (TPST), the trans-Golgi network (TGN)-resident 'source enzyme, and a 'sink' activity that removes tyrosine sulfation from CCR5. By measuring the effects on ligand binding of knockdown and overexpression experiments, we provided evidence that non-lysosomal cellular arylsulfatases, particularly ARSG, ARSI and ARSJ, are CCR5 sulfation 'sink' enzymes. We also used targeted knockdown and sialylation-sensitive and insensitive chemokines to identify the sialidase NEU3 as a candidate 'sink' enzyme for CCR5 O-glycan sialylation. This study provides the first experimental evidence of activity of sulfatase and sialidase 'sink' enzymes on CCR5, providing a potential mechanism for cells to control steady-state levels of these PTMs and thereby exert dynamic control over receptor-ligand interactions at the cell surface and during receptor desensitization.
  4. Int J Biol Macromol. 2023 Dec 28. pii: S0141-8130(23)05931-7. [Epub ahead of print]259(Pt 1): 129032
      Heparin, a bio-molecule with the highest negative charge density, is pharmaceutically important to prevent SARS-CoV-2 infection due to its strong competitive binding to spike protein compared with cellular heparan sulfate, which was confirmed as a co-receptor for virus-host cell interaction. Hence, the refined structural characterization of heparin targeting viral protein-HS interaction was significant for developing antiviral pharmaceuticals. In our study, heparin oligomers (dp ≥ 4) were prepared using heparinase I. The affinity oligosaccharides binding to Omicron spike protein RBD were separated by affinity chromatography and size exclusion chromatography. HILIC-ESI-FTMS was used for chain mapping analysis. The basic building blocks were analyzed and the binding domain sequence was produced by Seq-GAG software and further measured by SAX chromatography. As results, heparin octasaccharide was found with significantly higher binding ability than hexasaccharide and tetrasaccharide, and the octasaccharide [ΔUA-GlcNS6S-GlcA-GlcNS6S-IdoA2S-GlcNS6S-IdoA2S-GlcNS6S] with 12 sulfate groups showed high binding to RBD. The mechanism of this structurally well-defined octasaccharide binding to RBD was further investigated by molecular docking. The affinity energy of optimal pose was -6.8 kcal/mol and the basic amino acid residues in RBD sequence (Arg403, Arg452, Arg493 and His505) were identified as the major contribution factor to interacting with sulfate/carboxyl groups on saccharide chain. Our study demonstrated that heparin oligosaccharide with well-defined structure could be potentially developed as anti-SARS-CoV-2 drugs.
    Keywords:  Heparin; Octasaccharide; Omicron; SARS-CoV-2; Spike protein RBD
  5. J Cutan Med Surg. 2023 Dec 29. 12034754231220935
      BACKGROUND: Pruritus is a common complaint in patients with end-stage renal disease. Indoxyl sulfate (IS) is a tryptophan end metabolite extremely renal excreted. Activated charcoal can interfere with IS intestinal absorption.OBJECTIVES: To evaluate the serum level of IS and the effect of activated charcoal on uremic pruritus.
    MATERIALS AND METHODS: In all, 135 participants were divided into 2 main groups. In total, 45 normal and healthy individuals as a control group and 90 patients on regular hemodialysis; 45 of these patients had uremic pruritus and the other 45 were not complaining of uremic pruritus. Serum IS was measured. Activated charcoal was used by patients with uremic pruritus. The severity of pruritus and Dermatology Life Quality Index (DLQI) were assessed.
    RESULTS: The serum IS was significantly elevated in uremic patients than in control subjects (P < .001) and significantly elevated in uremic patients without pruritus (P < .001). Furthermore, there were positive significant correlations between the serum IS and both severity of pruritus (P < .001) and DLQI (P < .001). After activated charcoal usage, there was a significant decrease in IS level with the improvement of pruritus and quality of life of patients.
    CONCLUSIONS: IS may play a role in uremic pruritus. Activated charcoal could be considered a treatment for uremic pruritus.
    Keywords:  activated charcoal; indoxyl sulfate; uremic pruritus
  6. J Acquir Immune Defic Syndr. 2024 Jan 02.
      BACKGROUND: HIV is associated with alterations in androgen hormone levels and sex hormone binding globulin (SHBG) in women. Higher SHBG has been associated with a lower risk of diabetes in the general population, but the contribution of HIV, androgen hormones, SHBG, and menopausal phase to diabetes is unclear.METHODS: From April 2003 through February 2020, 896 women with HIV (WWH) and 343 women without HIV (WWOH) from the Women's Interagency HIV Study with morning total testosterone (TT), dehydroepiandrosterone sulfate (DHEAS), and SHBG levels were followed to assess for incident diabetes. Parametric regression models were used with age as the time scale and relative times (RT) as the measure of association of hormone level and menopausal phase with incident diabetes. Analyses incorporated time-dependent androgen hormone, SHBG levels, menopausal phase and were adjusted for race/ethnicity, enrollment year, smoking status, BMI, HCV status, and HIV-related factors.
    RESULTS: 128 (14%) WWH and 47 (14%) WWOH developed diabetes. In WWH, a doubling of SHBG and DHEAS were associated with a 7%(RT=1.07[95%CI:0.82,1.40] and 15%(RT=1.15[95%CI:0.95,1.39]) longer times to diabetes, respectively; in WWOH, a doubling of SHBG and DHEAS were associated with 84%(RT=1.84[95%CI:0.89,3.82]) and 41%(RT= 1.41[95%CI:0.82,2.44]) longer times to diabetes. TT was not associated. In WWH, later menopausal phase was associated with shorter times to diabetes.
    CONCLUSIONS: Despite alterations in androgen hormone and SHBG levels in HIV, regardless of HIV status, higher SHBG and DHEAS were associated with non-statistically significant slower progression to diabetes. The menopausal transition may be a better hormonal indicator of diabetes risk in WWH.
  7. Cell Rep. 2023 Dec 30. pii: S2211-1247(23)01652-2. [Epub ahead of print]43(1): 113641
      Immune checkpoint blockade (ICB) is a promising therapy for solid tumors, but its effectiveness depends on biomarkers that are not precise. Here, we utilized genome-wide association study to investigate the association between genetic variants and tumor mutation burden to interpret ICB response. We identified 16 variants (p < 5 × 10-8) probed to 17 genes on 9 chromosomes. Subsequent analysis of one of the most significant loci in 19q13.11 suggested that the rs111308825 locus at the enhancer is causal, as its A allele impairs KLF2 binding, leading to lower carbohydrate sulfotransferase 8 (CHST8) expression. Breast cancer cells expressing CHST8 suppress T cell activation, and Chst8 loss attenuates tumor growth in a syngeneic mouse model. Further investigation revealed that programmed death-ligand 1 (PD-L1) and its homologs could be sulfated by CHST8, resulting in M2-like macrophage enrichment in the tumor microenvironment. Finally, we confirmed that low-CHST8 tumors have better ICB response, supporting the genetic effect and clinical value of rs111308825 for ICB efficacy prediction.
    Keywords:  CP: Cancer; CP: Immunology; GWAS; GalNAc-4-ST1; KLF2; PD-L1; glycan sulfation; immune checkpoint blockade; macrophages; mannose receptor; single-nucleotide polymorphism; tumor mutation burden
  8. Heliyon. 2024 Jan 15. 10(1): e23222
      The ongoing challenge of managing coronaviruses, particularly SARS-CoV-2, necessitates the development of effective antiviral agents. This study introduces Lactulose octasulfate (LOS), a sulfated disaccharide, demonstrating significant antiviral activity against key coronaviruses including SARS-CoV-2, SARS-CoV, and MERS-CoV. We hypothesize LOS operates extracellularly, targeting the ACE2-S-protein axis, due to its low cellular permeability. Our investigation combines biolayer interferometry (BLI), isothermal titration calorimetry (ITC)-based experiments with in silico studies, revealing LOS's ability to reduce SARS-CoV-2's RBD's affinity for ACE2 in a dose-dependent manner, and bind tightly to ACE2 without inhibiting its enzymatic activity. Gaussian accelerated molecular dynamics simulations (GaMD) further supported these findings, illustrating LOS's potential as a broad-spectrum antiviral agent against current and future coronavirus strains, meriting in vivo and clinical exploration.
    Keywords:  Bio-layer interferometry; COVID-19; GaMD; MD simulation; Spike protein; Sulfated carbohydrates
  9. J Mater Chem B. 2024 Jan 03.
      Intervertebral disk degeneration (IVDD) is a common condition that causes severe back pain and affects patients' mobility and life quality considerably. IVDD originates within the central region of the disk called the nucleus pulposus (NP). Removing the damaged tissue and replacing it with NP cells (NPCs) delivered within an in situ forming hydrogel is a promising treatment approach. Herein we describe a hydrogel formulation based on 4-arm [poly(ethylene glycol)-b-poly(trimethylene carbonate)-acrylate] (4a[PEG-b-PTMC-Ac]) crosslinked with thiolated chondroitin sulfate via Michael-type reaction for this purpose. A library of hydrogels based on 15 kDa 4a-[PEG] with PTMC blocks of varying molecular weight were prepared and characterized. The instantaneous moduli of the hydrogels were adjustable from 24 to 150 kPa depending on the length of the PTMC block and the polymer volume fraction. The influence of each of these parameters was effectively explained using both scaling or mean field theories of polyelectrolyte hydrogels. The hydrogels were resistant to cyclic compressive loading and degraded gradually over 70 days in vitro. A hydrogel formulation with an instantaneous modulus at the high end of the range of values reported for human NP tissue was chosen to assess the ability of these hydrogels for delivering NPCs. The prepolymer solution was injectable and formed a hydrogel within 30 minutes at 37 °C. Bovine NPCs were encapsulated within this hydrogel with high viability and proliferated throughout a 28 day, hypoxic culture period. The encapsulated NPCs formed clusters and deposited collagen type II but no collagen type I within the hydrogels. Despite an initial gradual decrease, a steady-state modulus was reached at the end of the 28 day culture period that was within the range reported for healthy human NP tissue. This in situ forming hydrogel formulation is a promising approach and with further development could be a viable clinical treatment for IVDD.