PERFORMANCE OF DIFFERENT SETS OF SINGLE-NUCLEOTIDE POLYMORPHISMS (SNP) FOR TYPING MYCOBACTERIUM TUBERCULOSIS(MTB) STRAINS LINEAGE AND MODERN/ANCIENT BEIJING SUBLINEAGE

SPARC expression in airway smooth muscle (ASM) cells and whether this is related to ER stress. We also investigated whether SPARC expression is altered in ASM cells from COPD subjects. Methods: ASM cells were stimulated with TGF-β in the presence or absence of chemical chaperones which alleviate ER stress. Cellular SPARC and markers of ER stress were measured by immunoblotting. Soluble SPARC was measured by ELISA. Results: Stimulation of ASM cells with TGF-β (5, 10ng/ml) for 24 or 72 h significantly enhanced cellular SPARC expression by approximately 4-fold. A significant increase in the concentration of soluble SPARC was also detected in culture supernatants: 136.5 16.1ng/ml (SEM) and 744.9 402.3ng/ml at 24h and 72h, respectively. TGF-β (10ng/ml) enhanced the expression of ER stress markers GRP78 and IRE1α by approximately 2.5 and 5-fold, respectively. The chemical chaperones 4PBA and TMAO completely inhibited TGF-β-induced cellular SPARC, but had a less pronounced effect on SPARC secretion. Notably, SPARC secretion in COPD ASM cells was reduced when compared to non-COPD ASM cells, both at baseline (44.9 14.6ng/ml vs 74.4 12.6ng/ml, n=5-6) and in response to TGF-β stimulation (285.9 66.6nl/ml vs 438.7 24.7ng/ml, n=5-6), although this was not statistically significant. Conclusions: Our studies suggest that the UPR regulates TGFβ-induced SPARC expression in ASM cells and that SPARC secretion is reduced in COPD. Further investigation of the underlying mechanisms may provide new insight into COPD pathogenesis. Acknowledgements: University of Technology Sydney (UTS) seed funding, UTS IRS and President Scholarships