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Helen P Makarenkova, Anastasia Gromova, Xin Tang, Driss Zoukhri, Valery I Shestopalov; THE ROLE OF PANX1 GLYCOPROTEIN IN LACRIMAL GLAND INFLAMMATION. Invest. Ophthalmol. Vis. Sci. 2017;58(8):4724.
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© ARVO (1962-2015); The Authors (2016-present)
Sjögren’s Syndrome is a systemic chronic autoimmune inflammatory disease that targets primarily the salivary and lacrimal glands (LG). Currently there is no cure, therefore cell-based regenerative therapy may represent a viable option. We have shown that progenitor cell engraftment is more efficient during LG regeneration phase vs acute inflammation phase. The induction of inflammation in the LG is facilitated by extracellular ATP and mediated by the pannexin-1 (Panx1) membrane channel glycoprotein. We hypothesized that suppression of inflammation through manipulation of Panx1 pathway activity can stimulate epithelial cell progenitors (EPCPs) engraftment.
The expression of pannexins in mouse LG was assayed by qRT-PCR, immunohistochemistry and RNA-sequencing. Acute LG inflammation was induced by intraglandular injection of 1 µg interleukin-1 alpha (IL1α). Thrombospondin-1-null (TSP-1-null) mouse was used as a model of chronic LG inflammation. EPCPs transplantation was performed to study cell engraftment. Panx1-specific blocking peptide 10panx (100 μm, sequence WRQAAFVDSY) prior to EPCP cell transplantation. Cell engraftment and area of inflammation were analyzed by microscopy. The unpaired two-tailed Student’s t-test was used to determine statistical significance.
Two pannexin isoforms, Panx1 and Panx2 were detected in the LG epithelial cells at both mRNAs and protein level. In the acute model of regeneration, Panx1 and pro-inflammatory cytokines and caspases 1 and 4 were strongly upregulated during the inflammatory phase, 1-3 days after IL-1 injection. In contrast, Panx2 was increased only during LG regeneration. The analysis of EPCP engraftment showed a significant and reproducible positive correlation between the 10panx peptide treatment and the number of engrafted cells per cross section, with an average increase of engrafted cells of approximately 63% relative to untreated controls. The same strategy showed efficacy in the TSP-1-null mouse chronic model: blocking inflammation by LG treatment with either 10panx peptide or by silencing caspase 4 using dsRNAi showed a significant decrease of total area (cumulative foci) affected by inflammation.
Our results suggest that the manipulation of Panx1 and/or Caspase4(11) is a new beneficial strategy to enhance donor cell engraftment and LG regeneration through the reduction of inflammation.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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