This work was supported in part by the University of Pittsburgh and the following NIH grants: 5R01AG16989 (D.E.W.), 5R01HG00932 (D.E.W.), and 5R01AG16992 (to Jeffrey R. O'Connell). In addition, parts of Meag2 were inspired by data generated under NIH grant 5R01DK55406 to Ranjan Deka.