Serpins, the vasculature, and viral therapeutics

Jakob Richardson, Kasinath Viswanathan, Alexandra Lucas

Research output: Contribution to journalReview articlepeer-review

43 Scopus citations


Serine protease inhibitors, termed serpins, are key regulators of numerous biological pathways that initiate inflammation, coagulation, angiogenesis, apoptosis, extracellular matrix composition and complement activation responses. Viruses have encoded serpins to guard themselves from host immune attack. The myxoma virus which infects rabbits secretes a highly potent anti-inflammatory serpin, Serp-1, which targets thrombolytic and thrombotic proteases as a means to fend off coagulation and inflammatory reactions to viral infection. These reactions act as a defense, produced by the host, to counter viral infection and invasion. When infused in animals after vascular injury, Serp-1 elicits exceptional anti-inflammatory activity, whereas the mammalian serpin, plasminogen activator inhibitor-1 (PAI-1), which also targets thrombotic and thrombolytic proteases can induce a pro-thrombotic response. During arterial injury, PAI-1 is highly expressed and increased PAI-1 concentration can result in acute thrombosis after aortic transplant in mouse models. The reactive center loop amino acid sequence is a fingerprint for serpin function and this function is highly sequence specific such that modification in this sequence can markedly alter activity. For instance, the alteration of the serpin reactive site loop P1-P11 amino acid sequence nullified the anti-inflammatory activity of Serp-1 and modification of P2-P7 initiated a pro-inflammatory response with vascular remodeling with aneurysm formation. Furthermore Serp-1 has demonstrated the capacity to utilize a mammalian serine protease receptor, the urokinase-type plasminogen activator receptor (uPAR), to alter cellular signaling in part through the actin binding protein cytoskeletal system (via filamin B). In this review, the molecular mechanisms relating inflammation and coagulation pathways to atherosclerosis and how the viral serpin, Serp-1, modifies these pathways in order to exhibit this profound anti-inflammatory activity without associated adverse thrombosis are discussed. Viral and vascular serpins targeting the thrombolytic cascade represent a potential new and untapped therapeutic resource.

Original languageEnglish (US)
Pages (from-to)1042-1056
Number of pages15
JournalFrontiers in Bioscience
Issue number1 P.889-1198
StatePublished - 2006
Externally publishedYes


  • Innate Immunity
  • Review
  • Serpins
  • Thrombolysis
  • Thrombosis
  • Vessel

ASJC Scopus subject areas

  • General Biochemistry, Genetics and Molecular Biology
  • General Immunology and Microbiology


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