DOI: 10.5061/dryad.73n5tb384
title: Proteoglycan 4 (lubricin) is a highly sialylated glycoprotein associated with cardiac valve damage in animal models of infective endocarditis

description: Streptococcus gordonii and Streptococcus sanguinis are primary colonizers
 of tooth surfaces and are generally associated with oral health, but can
 also cause infective endocarditis (IE). These species express
 “Siglec-like” adhesins that bind sialylated glycans on host glycoproteins,
 which can aid the formation of infected platelet–fibrin thrombi
 (vegetations) on cardiac valve surfaces. We previously determined that the
 ability of S. gordonii to bind sialyl T-antigen (sTa) increased
 pathogenicity, relative to recognition of sialylated core 2 O-glycan
 structures, in an animal model of IE. However, it is unclear when and
 where the sTa structure is displayed, and which sTa-modified host factors
 promote valve colonization. In this study, we identified sialylated
 glycoproteins in the aortic valve vegetations and plasma of rat and rabbit
 models of this disease. Glycoproteins that display sTa vs. core 2 O-glycan
 structures were identified by using recombinant forms of the streptococcal
 Siglec-like adhesins for lectin blotting and affinity capture, and the
 O-linked glycans were profiled by mass spectrometry. Proteoglycan 4
 (PRG4), also known as lubricin, was a major carrier of sTa in the infected
 vegetations. Moreover, plasma PRG4 levels were significantly higher in
 animals with damaged or infected valves, as compared with healthy animals.
 The combined results demonstrate that, in addition to platelet GPIbα, PRG4
 is a highly sialylated mucin-like glycoprotein found in aortic valve
 vegetations and may contribute to the persistence of oral streptococci in
 this protected endovascular niche. Moreover, plasma PRG4 could serve as a
 biomarker for endocardial injury and infection.
description: # Proteoglycan 4 (lubricin) is a highly sialylated glycoprotein associated
 with cardiac valve damage in animal models of infective endocarditis
 Dataset DOI: [10.5061/dryad.73n5tb384](10.5061/dryad.73n5tb384) This data
 set was used to compare the levels of PRG4/lubricin in the plasma of 8
 rats in an animal model of infective endocarditis. Plasma samples were
 collected from each animal at 3 time points: a) pre-surgery; b) 3-days
 after placement of a trans-aortic valve catheter; c) 3 days after
 infection with Streptococcus gordonii. DATA & FILE OVERVIEW 1. File
 list: A) rats171009_2abc3abc4abc_PRG4western.tif B)
 1710093a_rats180115_1abc2abc3abc_PRG4western.tif C)
 1710093a_rats180226_1abc2abc_PRG4western.tif D)
 Fig4A_ImageJ_MeasuredValues.csv E) Fig4A_NormalizedValues.csv 1.
 Relationship between files: The .csv files contain data gathered from the
 three .tif files. ## DATA-SPECIFIC INFORMATION FOR:
 rats171009\_2abc3abc4abc\_PRG4western.tif Lane 1: rat1710092 condition a
 Lane 2: rat1710092 condition b Lane 3: rat1710092 condition c Lane 4:
 rat1710093 condition a Lane 5: rat1710093 condition b Lane 6: rat1710093
 condition c Lane 7: rat1710094 condition a Lane 8: rat1710094 condition b
 Lane 9: rat1710094 condition c Lanes 10&11: molecular weight standards
 ## DATA-SPECIFIC INFORMATION FOR:
 1710093a\_rats180115\_1abc2abc3abc\_PRG4western.tif Lane 1: molecular
 weight standards Lane 2: rat1710093 condition a Lane 3: rat1801151
 condition a Lane 4: rat1801151 condition b Lane 5: rat1801151 condition c
 Lane 6: rat1801152 condition a Lane 7: rat1801152 condition b Lane 8:
 rat1801152 condition c Lane 9: rat1801153 condition a Lane 10: rat1801153
 condition b Lane 11: rat1801153 condition c Lane 12: molecular weight
 standards ## DATA-SPECIFIC INFORMATION FOR:
 1710093a\_rats180226\_1abc2abc\_PRG4western.tif Lane 1: molecular weight
 standards Lane 2: rat1710093 condition a Lane 3: rat1802261 condition a
 Lane 4: rat1802261 condition b Lane 5: rat1802261 condition c Lane 6:
 rat1802262 condition a Lane 7: rat1802262 condition b Lane 8: rat1802262
 condition c ## DATA-SPECIFIC INFORMATION FOR:
 Fig4A\_ImageJ\_MeasuredValues.csv ImageJ was used for densitometry of the
 uppermost bands (the PRG4 signals) in the accompanying western blots. The
 reported values correspond to pixel counts. ## DATA-SPECIFIC INFORMATION
 FOR: Fig4A\_NormalizedValues.csv Pixel values from file
 Fig4A_ImageJ_MeasuredValues.csv were normalized to the measured value of
 rat1710093 condition a.