title: The clearance of cell remnants and the regeneration of the injured muscle depend on soluble pattern recognition receptor PTX3.
abstract: OBJECTIVE
  The signals causing the resolution of muscle inflammation are only partially characterized. The long pentraxin PTX3, which modulates leukocyte recruitment and activation, could contribute.
  
  
  METHODS
  We analysed the expression of ptx3 after muscle injury and verified whether hematopoietic precursors are a source of the protein. The kinetics of regeneration and leukocytes infiltration, the accumulation of cell remnants and anti-histidyl-t-RNA synthetase autoantibodies were compared in wild-type andptx3-deficient mice.
  
  
  RESULTS
  Ptx3 expression was up-regulated three-five days after injury and restricted to the extracellular matrix. Cellular debris and leukocytes persisted in the muscle ofptx3-deficient mice for a long time after wild-type animals had healed.ptx3-deficient macrophages expressed receptors involved in apoptotic cell clearance and engulfed dead cellsin vitro. Accumulation of cell debris in a pro-inflammatory microenvironment was not sufficient to elicit autoantibodies.
  
  
  CONCLUSIONS
  PTX3 generated in response to muscle injury prompts the clearance of debris and the termination of the inflammatory response.
authors.affiliation: Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Michela
authors.initials: M
authors.lastname: Vezzoli
authors.affiliation: Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Clara
authors.initials: C
authors.lastname: Sciorati
authors.affiliation: Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Lara
authors.initials: L
authors.lastname: Campana
authors.affiliation: Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Monno
authors.affiliation: Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Maria Giulia
authors.initials: MG
authors.lastname: Doglio
authors.affiliation: Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Rigamonti
authors.affiliation: Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Gianfranca
authors.initials: G
authors.lastname: Corna
authors.affiliation: Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Thierry
authors.initials: T
authors.lastname: Touvier
authors.affiliation: Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Castiglioni
authors.affiliation: Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Capobianco
authors.affiliation: Humanitas Clinical and Research Center, Rozzano, Milano, Italy.|Humanitas University, Rozzano, Milan, Italy.
authors.forename: Alberto
authors.initials: A
authors.lastname: Mantovani
authors.affiliation: Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.|Vita-Salute San Raffaele University, School of Medicine, Milano, Italy.
authors.forename: Angelo A
authors.initials: AA
authors.lastname: Manfredi
authors.affiliation: Humanitas Clinical and Research Center, Rozzano, Milano, Italy.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Garlanda
authors.affiliation: Division of Immunology, Transplantation and Infectious Disease, San Raffaele Scientific Institute, Milano, Italy.|Vita-Salute San Raffaele University, School of Medicine, Milano, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Rovere-Querini
keywords: Apoptosis; cell death; immunology; inflammation; rheumatology