Heparan sulfate and heparanase play key roles in mouse β cell survival and autoimmune diabetes
Andrew F. Ziolkowski, … , Christopher R. Parish, Charmaine J. Simeonovic
Andrew F. Ziolkowski, … , Christopher R. Parish, Charmaine J. Simeonovic
Published December 19, 2011
Citation Information: J Clin Invest. 2012;122(1):132-141. https://doi.org/10.1172/JCI46177.
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Research Article Metabolism

Heparan sulfate and heparanase play key roles in mouse β cell survival and autoimmune diabetes

Abstract

The autoimmune type 1 diabetes (T1D) that arises spontaneously in NOD mice is considered to be a model of T1D in humans. It is characterized by the invasion of pancreatic islets by mononuclear cells (MNCs), which ultimately leads to destruction of insulin-producing β cells. Although T cell dependent, the molecular mechanisms triggering β cell death have not been fully elucidated. Here, we report that a glycosaminoglycan, heparan sulfate (HS), is expressed at extraordinarily high levels within mouse islets and is essential for β cell survival. In vitro, β cells rapidly lost their HS and died. β Cell death was prevented by HS replacement, a treatment that also rendered the β cells resistant to damage from ROS. In vivo, autoimmune destruction of islets in NOD mice was associated with production of catalytically active heparanase, an HS-degrading enzyme, by islet-infiltrating MNCs and loss of islet HS. Furthermore, in vivo treatment with the heparanase inhibitor PI-88 preserved intraislet HS and protected NOD mice from T1D. Our results identified HS as a critical molecular requirement for islet β cell survival and HS degradation as a mechanism for β cell destruction. Our findings suggest that preservation of islet HS could be a therapeutic strategy for preventing T1D.

Authors

Andrew F. Ziolkowski, Sarah K. Popp, Craig Freeman, Christopher R. Parish, Charmaine J. Simeonovic

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Figure 2

HS replacement protects isolated β cells from culture-induced and ROS-induced cell death in vitro.

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HS replacement protects isolated β cells from culture-induced and ROS-in...
(A) Flow cytometry analysis of isolated β cell viability after culture for 2 days in the absence (control) or presence of 50 μg/ml heparin, HShi, or PI-88. Viability was assessed by Sytox green uptake or by calcein-AM (viable and apoptotic cells) and PI (dead and apoptotic cells) uptake (see Supplemental Table 1). CB, counting beads. Percent cells is shown for the respective regions. (B) Absolute number of β cells and number of dead β cells in 2 day cultures as in A. The number of β cells was calculated using counting beads. See Supplemental Table 1 for statistical analyses of the same day 2 cultures (note that percent Sytox green+ cells approximated percent PI+ cells). (C) Coculture with HShi, but not HSlo, protected isolated islet β cells from 2 day culture–induced cell death, as determined by percent Sytox green+ cells and intracellular insulin staining of β cells. GMFR for insulin staining was compared with serum control. *P < 0.05 vs. control. (D) Ability of β cells cultured in the presence or absence of heparin (50 μg/ml) for 1 hour or 1–2 days to resist H2O2-induced (i.e., ROS) cell death (see Table 1). Data in A and D are representative of 3–5 separate experiments.