• Dentin Sialophosphoprotein (DSPP) Gene-Silencing Inhibits Key Tumorigenic Activities in Human Oral Cancer Cell Line, OSC2

      Joshi, Rajeshree; Tawfik, Amany; Edeh, Nneka; McCloud, Veronica; Looney, Stephen W.; Lewis, Jill; Hsu, Stephen; Ogbureke, Kalu U.E.; Department of Oral Biology; Department of Pathology; et al. (2010-11-12)
      Background: We determined recently that dentin sialophosphoprotein (DSPP), a member of the SIBLING (Small integrin-binding ligand N-linked glycoproteins) family of phosphoglycoproteins, is highly upregulated in human oral squamous cell carcinomas (OSCCs) where upregulation is associated with tumor aggressiveness. To investigate the effects of DSPP-silencing on the tumorigenic profiles of the oral cancer cell line, OSC2, short-hairpin RNA (shRNA) interference was employed to silence DSPP in OSC2 cells.
    • Differential effects of taurine treatment and taurine deficiency on the outcome of renal ischemia reperfusion injury

      Mozaffari, Mahmood S.; Abdelsayed, Rafik; Patel, Champa; Wimborne, Hereward J. C.; Liu, Jun Yao; Schaffer, Stephen W; Department of Oral Biology; Department of Oral Health and Diagnostic Sciences (2010-08-24)
      Taurine possesses membrane stabilization, osmoregulatory and antioxidant properties, aspects of relevance to ischemic injury. We tested the hypothesis that body taurine status is a determinant of renal ischemic injury. Accordingly, renal function and structure were examined in control (C), taurine-treated (TT) and taurine deficient (TD) rats that were subjected to bilateral renal ischemia (60 min) followed by reperfusion (IR); sham operated rats served as controls. Baseline urine osmolality was greater in the TD group than in the control and the TT groups, an effect associated with increased renal aquaporin 2 level. The IR insult reduced urine osmolality (i.e., day-1 post insult); the TD/IR group displayed a more marked recovery in urine osmolality by day-6 post insult than the other two groups. Fluid and sodium excretions were lower in the TD/IR group, suggesting propensity to retention. Histopathological examination revealed the presence of tubular necrotic foci in the C/IR group than sham controls. While renal architecture of the TD/IR group showed features resembling sham controls, the TT/IR group showed dilated tubules, which lacked immunostaining for aquaporin 2, but not 1, suggestive of proximal tubule origin. Finally, assessment of cell proliferation and apoptosis revealed lower proliferation but higher apoptotic foci in the TT/IR group than other IR groups. Collectively, the results indicate that body taurine status is a major determinant of renal IR injury.