Early window of diabetes determinism in NOD mice, dependent on the complement receptor CRIg, identified by noninvasive imaging.

Division of Immunology, Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, USA.
Nature Immunology (Impact Factor: 24.97). 02/2012; 13(4):361-8. DOI: 10.1038/ni.2233
Source: PubMed

ABSTRACT All juvenile mice of the nonobese diabetic (NOD) strain develop insulitis, but there is considerable variation in their progression to diabetes. Here we used a strategy based on magnetic resonance imaging (MRI) of magnetic nanoparticles to noninvasively visualize local effects of pancreatic-islet inflammation to predict the onset of diabetes in NOD mice. MRI signals acquired during a narrow early time window allowed us to sort mice into groups that would progress to clinical disease or not and to estimate the time to diabetes development. We exploited this approach to identify previously unknown molecular and cellular elements correlated with disease protection, including the complement receptor of the immunoglobulin superfamily (CRIg), which marked a subset of macrophages associated with diabetes resistance. Administration of a fusion of CRIg and the Fc portion of immunoglobulin resulted in lower MRI signals and diabetes incidence. In addition to identifying regulators of disease progression, we show here that diabetes is set at an early age in NOD mice.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Vascular inflammation is a major contributor to the severity of acute kidney injury. In the context of vasospasm-independent reperfusion injury we studied the potential anti-inflammatory role of the Gα-related RGS protein, RGS4. Transgenic RGS4 mice were resistant to 25 min injury, although post-ischemic renal arteriolar diameter was equal to the wild type early after injury. A 10 min unilateral injury was performed to study reperfusion without vasospasm. Eighteen hours after injury, blood flow was decreased in the inner cortex of wild-type mice with preservation of tubular architecture. Angiotensin II levels in the kidneys of wild-type and transgenic mice were elevated in a sub-vasoconstrictive range 12 and 18 h after injury. Angiotensin II stimulated pre-glomerular vascular smooth muscle cells (VSMCs) to secrete the macrophage chemoattractant RANTES, a process decreased by angiotensin II R2 (AT2) inhibition. However, RANTES increased when RGS4 expression was suppressed implicating Gα protein activation in an AT2-RGS4-dependent pathway. RGS4 function, specific to VSMC, was tested in a conditional VSMC-specific RGS4 knockout showing high macrophage density by T2 MRI compared with transgenic and non-transgenic mice after the 10 min injury. Arteriolar diameter of this knockout was unchanged at successive time points after injury. Thus, RGS4 expression, specific to renal VSMC, inhibits angiotensin II-mediated cytokine signaling and macrophage recruitment during reperfusion, distinct from vasomotor regulation.Kidney International advance online publication, 3 December 2014; doi:10.1038/ki.2014.364.
    Kidney International 12/2014; · 8.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: In type 1 diabetes, the pancreatic islets are an important site for therapeutic intervention because immune infiltration of the islets is well established at diagnosis. Therefore, understanding the events that underlie the continued progression of the autoimmune response and islet destruction is critical. Islet infiltration and destruction is an asynchronous process, making it important to analyze the disease process on a single islet basis. To understand how T cell stimulation evolves through the process of islet infiltration, we analyzed the dynamics of T cell movement and interactions within individual islets of spontaneously autoimmune NOD mice. Using both intravital and explanted two-photon islet imaging, we defined a correlation between increased islet infiltration and increased T cell motility. Early T cell arrest was Ag dependent and due, at least in part, to Ag recognition through sustained interactions with CD11c(+) APCs. As islet infiltration progressed, T cell motility became Ag independent, with a loss of T cell arrest and sustained interactions with CD11c(+) APCs. These studies suggest that the autoimmune T cell response in the islets may be temporarily dampened during the course of islet infiltration and disease progression. Copyright © 2014 by The American Association of Immunologists, Inc.
    Journal of immunology (Baltimore, Md. : 1950). 12/2014;
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Type 1 diabetes (T1D) is an autoimmune disease of the beta cells of the pancreas. The nonobese diabetic (NOD) mouse is a commonly used animal model, with roughly an 80% incidence rate of T1D among females. In 100% of NOD mice, macrophages and T-cells invade the islets in a process called insulitis. It can be several weeks between insulitis and T1D, and some mice do not progress at all. It is thought that this delay is mediated by regulatory T-cells (Tregs) and that a gradual loss of effectiveness in this population leads to T1D. However, this does not explain why some mice progress and others do not. We propose a simple mathematical model of the interaction between beta cells and the immune populations, including regulatory T-cells. We find that individual mice may enter one of two stable steady states: a `mild' insulitis state that does not progress to T1D and a `severe' insulitis state that does. We then run a sensitivity analysis to identify which parameters affect incidence of T1D versus those that affect age of onset. We also test the model by simulating several experimental manipulations found in the literature that modify insulitis severity and/or Treg activity. Notably, we are able to match a reproduce a large number of phenomena using a relatively small number of equations. We finish by proposing experiments that could help validate or refine the model.


1 Download
Available from