Characterization of PF4-Heparin Complexes by Photon Correlation Spectroscopy and Zeta Potential

Bertini, Sabrina; Fareed, Jawed; Madaschi, Laura; Risi, Giulia; Torri, Giangiacomo; Naggi, Annamaria

doi:10.1177/1076029616685430

Cited by 18 publications

(11 citation statements)

References 19 publications

(32 reference statements)

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“…1 A, bottom trace). The absence of any detectable signal of the tetrameric form of this protein might seem surprising because PF4 is frequently stated to have a stable tetrameric form at a physiological pH and ionic strength (5,26) without explicitly mentioning the critical importance of endogenous GAGs in stabilizing this form in vivo. However, the original work by Barber et al noted that PF4 was released from platelets in the form of a complex with chondroitin sulfate proteoglycans (23).…”

Section: Resultsmentioning

confidence: 99%

Platelet Factor 4 Interactions with Short Heparin Oligomers: Implications for Folding and Assembly

Niu

Yang

Huynh

et al. 2020

Biophysical Journal

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Association of platelet factor 4 (PF4) with heparin is a first step in formation of aggregates implicated in the development of heparin-induced thrombocytopenia (HIT), a potentially fatal immune disorder affecting 1-5% of patients receiving heparin. Despite being a critically important element in HIT etiology, relatively little is known about the specific molecular mechanism of PF4-heparin interactions. This work uses native mass spectrometry to investigate PF4 interactions with relatively short heparin chains (up to decasaccharides). The protein is shown to be remarkably unstable at physiological ionic strength in the absence of polyanions; only monomeric species are observed, and the extent of multiple charging of corresponding ions indicates a partial loss of conformational integrity. The tetramer signal remains at or below the detection threshold in the mass spectra until the solution's ionic strength is elevated well above the physiological level, highlighting the destabilizing role played by electrostatic interactions vis-à -vis quaternary structure of this high-pI protein. The tetramer assembly is dramatically facilitated by relatively short polyanions (synthetic heparin-mimetic pentasaccharide), with the majority of the protein molecules existing in the tetrameric state even at physiological ionic strength. Each tetramer accommodates up to six pentasaccharides, with at least three such ligands required to guarantee the higher-order structure integrity. Similar results are obtained for PF4 association with longer and structurally heterogeneous heparin oligomers (decamers). These longer polyanions can also induce PF4 dimer assembly when bound to the protein in relatively low numbers, lending support to a model of PF4/heparin interaction in which the latter wraps around the protein, making contacts with multiple subunits. Taken together, these results provide a more nuanced picture of PF4-glycosaminoglycan interactions leading to complex formation. This work also advocates for a greater utilization of native mass spectrometry in elucidating molecular mechanisms underlying HIT, as well as other physiological processes driven by electrostatic interactions.

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Section: Resultsmentioning

confidence: 99%

Platelet Factor 4 Interactions with Short Heparin Oligomers: Implications for Folding and Assembly

Niu

Yang

Huynh

et al. 2020

Biophysical Journal

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“…Moreover, HBI and HPI also have the same ability in forming the large UFH-PF4 complexes that are preferably recognized by HIT antibodies. 43 Notwithstanding these indirect evidences, the intrinsic potential of HBI in provoking this life-threatening adverse effect deserves further clinical investigations.…”

Section: Discussionmentioning

confidence: 99%

Converting the Distinct Heparins Sourced from Bovine or Porcine Mucosa into a Single Anticoagulant Drug

et al. 2019

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Unfractionated heparin (UFH) and their low-molecular-weight derivatives are sourced almost exclusively from porcine mucosa (HPI); however, a worldwide introduction of UFH from bovine mucosa (HBI) has been recommended to reinforce the currently unsteady supply chain of heparin products. Although HBI has different chemical composition and about half of the anticoagulant potency of HPI (∼100 and ∼180 international unit [IU]/mg, respectively), they have been employed as interchangeable UFHs in some countries since the 1990s. However, their use as a single drug provoked several bleeding incidents in Brazil, which precipitated the publication of the first monographs exclusive for HBI and HPI by the Brazilian Pharmacopoeia. Nevertheless, we succeed in producing with high-resolution anion-exchange chromatography a novel HBI derivative with anticoagulant potency (200 IU/mg), disaccharide composition (enriched in N,6-disulfated α-glucosamine) and safety profile (bleeding and heparin-induced thrombocytopaenia potentials and protamine neutralization) similar to those seen in the gold standard HPI. Therefore, we show that it is possible to equalize the composition and pharmacological characteristics of these distinct UFHs by employing an easily implementable improvement in the HBI manufacturing.

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“…While UFH molecules may range in size from 6 to 60 kDa, those for LMWHs vary between 1 and 10 kDa. 5,6 Many different types of LMWHs exist (e.g., Food and Drug Administration-approved dalteparin, enoxaparin, and tinzaparin) with the more recent generation of second-generation LMWH or ultralow molecular weight heparins such as bemiparin and semuloparin (reviewed in Walenga and Lyman 7 ). All these LMWH preparations express different activities toward FXa and have different pharmacokinetic profiles.…”

Section: Heparin and Its Derivativesmentioning

confidence: 99%

The Anticoagulant and Nonanticoagulant Properties of Heparin

et al. 2020

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Heparins represent one of the most frequently used pharmacotherapeutics. Discovered around 1926, routine clinical anticoagulant use of heparin was initiated only after the publication of several seminal papers in the early 1970s by the group of Kakkar. It was shown that heparin prevents venous thromboembolism and mortality from pulmonary embolism in patients after surgery. With the subsequent development of low-molecular-weight heparins and synthetic heparin derivatives, a family of related drugs was created that continues to prove its clinical value in thromboprophylaxis and in prevention of clotting in extracorporeal devices. Fundamental and applied research has revealed a complex pharmacodynamic profile of heparins that goes beyond its anticoagulant use. Recognition of the complex multifaceted beneficial effects of heparin underscores its therapeutic potential in various clinical situations. In this review we focus on the anticoagulant and nonanticoagulant activities of heparin and, where possible, discuss the underlying molecular mechanisms that explain the diversity of heparin's biological actions.

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Characterization of PF4-Heparin Complexes by Photon Correlation Spectroscopy and Zeta Potential

Cited by 18 publications

References 19 publications

Platelet Factor 4 Interactions with Short Heparin Oligomers: Implications for Folding and Assembly

Platelet Factor 4 Interactions with Short Heparin Oligomers: Implications for Folding and Assembly

Converting the Distinct Heparins Sourced from Bovine or Porcine Mucosa into a Single Anticoagulant Drug

The Anticoagulant and Nonanticoagulant Properties of Heparin

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