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Wilk, Katarzyna

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Wilk

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Katarzyna

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Wilk, Katarzyna
Author's Publications: search.filters.isAuthorOfPublication.807a363d-1c51-4623-8528-c385f64d490f

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    Postnatal Calvarial Skeletal Stem Cells Expressing PRX1 Reside Exclusively in the Calvarial Sutures and Are Required for Bone Regeneration
    (Elsevier, 2017) Wilk, Katarzyna; Yeh, Shu-Chi; Mortensen, Luke J.; Ghaffarigarakani, Sasan; Lombardo, Courtney M.; Bassir, Seyed Hossein; Aldawood, Zahra; Lin, Charles; Intini, Giuseppe
    Summary Post-natal skeletal stem cells expressing PRX1 (pnPRX1+) have been identified in the calvaria and in the axial skeleton. Here we characterize the location and functional capacity of the calvarial pnPRX1+ cells. We found that pnPRX1+ reside exclusively in the calvarial suture niche and decrease in number with age. They are distinct from preosteoblasts and osteoblasts of the sutures, respond to WNT signaling in vitro and in vivo by differentiating into osteoblasts, and, upon heterotopic transplantation, are able to regenerate bone. Diphtheria toxin A (DTA)-mediated lineage ablation of pnPRX1+ cells and suturectomy perturb regeneration of calvarial bone defects and confirm that pnPRX1+ cells of the sutures are required for bone regeneration. Orthotopic transplantation of sutures with traceable pnPRX1+ cells into wild-type animals shows that pnPRX1+ cells of the suture contribute to calvarial bone defect regeneration. DTA-mediated lineage ablation of pnPRX1+ does not, however, interfere with calvarial development.
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    Differential Gene Expression and Pathway Analysis of Prx1-Expressing Cells in Calvarial Sutures and Long Bone Periosteum
    (2017-04-17) Wilk, Katarzyna; Denkin, Steven; Intini, Giuseppe
    The Pair-related homeobox transcription factor (Prx1) is required for normal development of the cranium and axial skeleton. Prx1-expressing cells are found in the suture of the calvaria and periosteum of the long bones, and function postnatally in the maintenance and regeneration of bone. We evaluated the 2 cell populations by RNA sequencing analysis in a comparative study to determine distinct cell surface targets for regenerative bone therapies in the craniofacial region and axial skeleton. Prx1-expressing cells tagged with green florescent protein (eGFP) were isolated by fluorescent-activated cell sorting (FACS) from the calvaria and long bones of neonate transgenic mice. RNA sequencing data was used to calculate differential gene expression levels and functional enrichment values for pathway analysis. The results validate previous findings obtained by conventional methods and provide a molecular map for future studies in Prx1-mediated bone ossification and bone homeostasis. The trends observed suggest that Prx1-expressing cells of the calvaria and long bones regulate cell-cell communication, cell adhesion, cell migration, vascularization and cross-talk between the mesenchymal stem cell microenvironment and hematopoietic stem cell microenvironment in addition to bone forming capabilities. Cell surface targets differentially expressed in Prx1-expressing cells of the calvaria and long bones are identified for future developments and applications in translational medicine.
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    Opsonic and Protective Properties of Antibodies Raised to Conjugate Vaccines Targeting Six Staphylococcus aureus Antigens
    (Public Library of Science, 2012) Pozzi, Clarissa; Wilk, Katarzyna; Lee, Jean; Gening, Marina; Nifantiev, Nikolay; Pier, Gerald
    Staphylococcus aureus is a major cause of nosocomial and community-acquired infections for which a vaccine is greatly desired. Antigens found on the S. aureus outer surface include the capsular polysaccharides (CP) of serotype 5 (CP5) or 8 (CP8) and/or a second antigen, a β-(1→6)-polymer of N-acetyl-D-glucosamine (PNAG). Antibodies specific for either CP or PNAG antigens have excellent in vitro opsonic killing activity (OPKA), but when mixed together have potent interference in OPKA and murine protection. To ascertain if this interference could be abrogated by using a synthetic non-acetylated oligosaccharide fragment of PNAG, 9GlcNH2, in place of chemically partially deacetylated PNAG, three conjugate vaccines consisting of 9GlcNH2 conjugated to a non-toxic mutant of alpha-hemolysin (Hla H35L), CP5 conjugated to clumping factor B (ClfB), or CP8 conjugated to iron-surface determinant B (IsdB) were used separately to immunize rabbits. Opsonic antibodies mediating killing of multiple S. aureus strains were elicited for all three vaccines and showed carbohydrate antigen-specific reductions in the tissue bacterial burdens in animal models of S. aureus skin abscesses, pneumonia, and nasal colonization. Carrier-protein specific immunity was also shown to be effective in reducing bacterial levels in infected lungs and in nasal colonization. However, use of synthetic 9GlcNH2 to induce antibody to PNAG did not overcome the interference in OPKA engendered when these were combined with antibody to either CP5 or CP8. Whereas each individual vaccine showed efficacy, combining antisera to CP antigens and PNAG still abrogated individual OPKA activities, indicating difficulty in achieving a multi-valent vaccine targeting both the CP and PNAG antigens.