Type 1 diabetes (T1D) in the nonobese diabetic (NOD) mouse can be delayed by administration of insulin or specific insulin peptides. To better understand how insulin treatment delays diabetes development, NOD mice treated with an insulin peptide (B9-23) were compared with age-matched NOD and NOD congenic mice for gene expression changes in spleen using cDNA microarray. Fifty genes were identified that were significantly altered by B9-23 treatment. Thirty-three of these genes are downregulated by the treatment while they are upregulated during the natural disease progression in NOD from immature (3-4 weeks) to mature (10 weeks) stages. Taken together, our data suggest that the B9-23 treatment, like the protective genes in NOD congenic strains, reduces pro-inflammatory activation of lymphocytes that normally occurs in NOD mice. Furthermore, our studies discovered two genes (Irf4 and Tra1) with increased expression in B9-23-treated mice that promote the Th2 response, providing a molecular basis for the B9-23-protective therapy.

cDNA microarrays with >11,000 cDNA clones from an NOD spleen cDNA library were used to identify temporal gene expression changes in NOD mice (1-10 weeks), which spontaneously develop type 1 diabetes, and changes between NOD and NOD congenic mice (NOD.Idd3/Idd10 and NOD.B10Sn-H2(b)), which have near zero incidence of insulitis and diabetes. The expression profiles identified two distinct groups of mice corresponding to an immature (1-4 weeks) and mature (6-10 weeks) state. The rapid switch of gene expression occurring around 5 weeks of age defines a key immunological checkpoint. Sixty-two known genes are upregulated, and 18 are downregulated at this checkpoint in the NOD. The expression profiles are consistent with increased antibody production, antigen presentation, and cell proliferation associated with an active autoimmune response. Seven of these genes map to confirmed diabetes susceptibility regions. Of these seven, three are excellent candidate genes not previously implicated in type 1 diabetes. Ten genes are differentially expressed between the NOD and congenic NOD at the immature stage (Hspa8, Hif1a, and several involved in cellular functions), while the other 70 genes exhibit expression differences during the mature (6-10 week) stage, suggesting that the expression differences of a small number of genes before onset of insulitis determine the disease progression.

Interferon alfa (IFN‐α)‐based treatment is the only therapeutic option for chronic hepatitis C viral infection. However, the molecular mechanisms of IFN‐α antiviral activity are not completely understood. The recent development of an HCV replicon cell culture system provides a feasible experimental model to investigate the molecular details of IFN‐induced direct antiviral activity in hepatocytes. In this report, we show that IFN‐α can effectively inhibit HCV subgenomic RNA replication and suppress viral nonstructural protein synthesis. Using cDNA microarray analysis, we also show that the replicon cells have different gene expression profile compared with the parental hepatoma cells (Huh7). IFN‐α can induce a number of responsive genes in the replicon cells. One of the genes, 6‐16 (G1P3), can enhance IFN‐α antiviral efficacy. In addition, we demonstrate that IFN‐α can significantly activate STAT3 in hepatoma cells, suggesting that this pathway plays a role in IFN‐α signaling. In conclusion, our results indicate that IFN‐α antiviral activity is associated with activation of STAT3‐signaling pathway and intracellular gene activation. Our results also suggest that IFN‐α‐induced target genes may play an important role in IFN‐α anti‐HCV activity.

We profiled the expression of 5,760 clones from a kidney subtraction library in the kidneys of three groups of NOD mice: nondiabetic, new-onset, and long-term diabetic. A total of 27 genes had lower expression and 1 gene (Gpx3) had higher expression in the new-onset diabetic mice compared with nondiabetic control NOD mice (P < 0.001). Similarly, 19 of the above 27 genes and 7 additional genes had higher expression and the Gpx3 gene had lower expression in long-term diabetic mice compared with controls (P < 0.001). Interestingly, only three genes may be different between new-onset and long-term diabetic mice (P < 0.0004). These genes are from diverse functional groups, including oxidative phosphorylation, free radical neutralization, channels, pumps, lipid processing, transcription and translation machinery, protein trafficking, constitutive protein processing, and immune function. The majority of these genes fall into four signaling pathways: insulin, transforming growth factor-beta, tumor necrosis factor-alpha, and peroxisome proliferator-activated receptor. The most significant expression change was found for the stearoyl-coenzyme A desaturase 1 (SCD1) gene (P < 10(-7)). The lower expression levels of the SCD1 gene in both diabetic groups compared with controls were further confirmed by Northern blot analysis and immunohistochemistry.

Polymorphic markers within the CTLA4 gene on chromosome 2q33 have been shown to be associated with type 1 diabetes. Therefore, a gene responsible for the disease (IDDM12) most likely lies within a region of <1-2 cM of CTLA4. To define more precisely the IDDM12 interval, we genotyped a multiethnic (U.S. Caucasian, Mexican-American, French, Spanish, Korean, and Chinese) collection of 178 simplex and 350 multiplex families for 10 polymorphic markers within a genomic interval of approximately 300 kb, which contains the candidate genes CTLA4 and CD28. The order of these markers (D2S346, CD28, GGAA19E07, D2S307, D2S72, CTLA4, D2S105, and GATA52A04) was determined by sequence tagged site content mapping of bacterial artificial chromosome (BAC) and yeast artificial chromosome (YAC) clones. The transmission disequilibrium test (TDT) analyses of our data revealed significant association/linkage with three markers within CTLA4 and two immediate flanking markers (D2S72 and D2S105) on each side of CTLA4 but not with more distant markers including the candidate gene CD28. Tsp analyses revealed significant association only with the three polymorphic markers within the CTLA4 gene. The markers linked and associated with type 1 diabetes are contained within a phagemid artificial chromosome clone of 100 kb, suggesting that the IDDM12 locus is either CTLA4 or an unknown gene in very close proximity.