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Inhibition of protein disulfide isomerase with PACMA-31 regulates monocyte tissue factor through transcriptional and

Lennart Beckmann1, Jonathan Mäder1, Minna Voigtlaender1

  • 1II. Medizinische Klinik und Poliklinik, Hubertus Wald Tumorzentrum - Universitäres Cancer Center Hamburg (UCCH), Universitätsklinikum Eppendorf, Hamburg, Germany.

Thrombosis Research
|October 20, 2022
PubMed
Abstract

Insights

PACMA-31, a protein disulfide isomerase inhibitor, affects monocyte tissue factor (TF) production differently based on concentration. Low doses enhance TF via PAR2 signaling, while high doses inhibit TF procoagulant activity.

Area of Science:

  • Immunology
  • Biochemistry
  • Molecular Biology

Background:

  • Protein disulfide isomerase (PDI) plays a role in regulating tissue factor (TF) production in monocytes.
  • Existing PDI inhibitors like bacitracin and quercetin-3-rutinoside mitigate myeloid TF production.
  • The specific effects of PACMA-31, a potent PDI inhibitor, on monocyte TF regulation are not well understood.

Purpose of the Study:

  • To investigate the impact of PACMA-31 on lipopolysaccharide (LPS)-induced TF expression and related signaling pathways in monocytes.
  • To determine the concentration-dependent effects of PACMA-31 on TF production and procoagulant activity.
  • To elucidate the mechanisms underlying PACMA-31's influence on monocyte inflammatory responses.

Main Methods:

  • Peripheral blood mononuclear cells (PBMCs) and whole blood were stimulated with LPS in the presence of varying concentrations of PACMA-31 or DMSO vehicle.
  • TF expression (antigen, procoagulant activity, mRNA), IL-6 and TNFα release, and signaling pathways were analyzed.
  • Inhibitors of protease-activated receptor 2 (PAR2) and TF, as well as a factor Xa inhibitor, were used to probe signaling mechanisms.

Main Results:

  • Low-dose PACMA-31 (25 μM) enhanced LPS-induced TF production in whole blood, partly via transcriptional regulation and increased IL-6/TNFα release, mediated by PAR2 signaling.
  • High-dose PACMA-31 (25 μM) inhibited TF procoagulant activity in LPS-stimulated PBMCs without affecting TF antigen expression or causing cytotoxicity.
  • PACMA-31's effects were concentration-dependent, influencing both transcriptional and posttranscriptional mechanisms of TF regulation.

Conclusions:

  • PACMA-31 exhibits dual concentration-dependent effects on monocyte TF regulation.
  • Low PACMA-31 concentrations augment monocyte TF production by amplifying LPS-dependent PAR2 signaling.
  • High PACMA-31 concentrations inhibit the procoagulant activity of TF, converting it to a non-coagulant state.
Keywords:
Blood coagulationInflammationMonocytesPACMA-31Protein disulfide isomeraseTissue factor

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