SUMMARY Immune cells sense microbial products through Toll-like receptors (TLR), which trigger host defense responses including type 1 interferons (IFNs) secretion. A coding polymorphism in the protein tyrosine phosphatase nonreceptor type 22 (PTPN22) gene is a susceptibility allele for human autoimmune and infectious disease. We report that Ptpn22 selectively regulated type 1 IFN production after TLR engagement in myeloid cells. Ptpn22 promoted host antiviral responses and was critical for TLR agonist-induced, type 1 IFN-dependent suppression of inflammation in colitis and arthritis. PTPN22 directly associated with TNF receptor-associated factor 3 (TRAF3) and promotes TRAF3 lysine 63-linked ubiquitination. The disease-associated PTPN22W variant failed to promote TRAF3 ubiquitination, type 1 IFN upregulation, and type 1 IFN-dependent suppression of arthritis. The findings establish a candidate innate immune mechanism of action for a human autoimmunity “risk” gene in the regulation of host defense and inflammation.

DJ-1 is the third gene that has been linked to Parkinson disease.Mutations in the DJ-1 gene cause early onset PD with autosomal recessive inheritance. To clarify the mechanism of DJ-1 protection, we have overexpressed the gene in cultured dopaminergic cells that were then subjected to chemical stress. In the rat dopaminergic cell line, N27, and in primary dopamine neurons, overexpression of wild type DJ-1 protected cells from death induced by hydrogen peroxide and 6-hydroxydopamine. Overexpressing the L166P mutant DJ-1 had no protective effect. By contrast, knocking down endogenous DJ-1 with antisense DJ-1 rendered cells more susceptible to oxidative damage. We have found that DJ-1 improves survival by increasing cellular glutathione levels through an increase in the rate-limiting enzyme glutamate cysteine ligase. Blocking glutathione synthesis eliminated the beneficial effect of DJ-1. Protection could be restored by adding exogenous glutathione. Wild type DJ-1 reduced cellular reactive oxygen species and reduced the levels of protein oxidation caused by oxidative stress. By a separate mechanism, overexpressing wild type DJ-1 inhibited the protein aggregation and cytotoxicity usually caused by A53T human ␣-synuclein. Under these circumstances, DJ-1 increased the level of heat shock protein 70 but did not change the glutathione level. Our data indicate that DJ-1 protects dopaminergic neurons from oxidative stress through up-regulation of glutathione synthesis and from the toxic consequences of mutant human ␣-synuclein through increased expression of heat shock protein 70. We conclude that DJ-1 has multiple specific mechanisms for protecting dopamine neurons from cell death. Parkinson disease (PD)2 is a common neurodegenerative disease characterized by the loss of dopaminergic neurons in the substantia nigra and by the presence of intracellular inclusions called Lewy bodies (1, 2). The etiology of PD may involve both genetic and environmental factors (3). In recent years, several genes linked to PD have been discovered. ␣-Synuclein was the first gene identified whose mutations, A53T and A30P, cause autosomal dominant forms of PD (4, 5). Importantly, aggregated ␣-synuclein has been found to be a major component of Lewy bodies (6). Mutations in a second gene, Parkin, cause early onset PD with autosomal recessive inheritance (7). Parkin is an ubiquitinprotein isopeptide ligase controlling protein degradation through the ubiquitin-proteasome system (8).DJ-1 is the third PD gene identified and is linked to early onset disease with autosomal recessive inheritance (9). Eleven different mutations have been found in the DJ-1 gene including missense, truncation, and splice site mutations as well as large deletions, suggesting that loss of DJ-1 function leads to neurodegeneration (9 -11). DJ-1 is a 189-amino acid protein with multiple functions (12). DJ-1 interacts with H-ras to increase cell transformation (13). DJ-1 is a regulatory subunit of an RNA-binding protein complex (14). Through binding to PIASx␣, the transcription...

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Mouse and human fibroblasts have been transformed into induced pluripotent stem (iPS) cells by retroviral transduction or plasmid transfection with four genes. Unfortunately, viral and plasmid DNA incorporation into chromosomes can lead to disruption of gene transcription and malignant transformation. Tumor formation has been found in offspring of mice generated from blastocysts made mosaic with iPS cells. To proceed with iPS cells for human therapy, reprogramming should be done with transient gene expression. Recently, adenoviral vectors have been used to produce mouse iPS cells without viral integration. Here, we report the successful creation of human iPS cells from embryonic fibroblasts using adenoviral vectors expressing c-Myc, Klf4, Oct4, and Sox2. After screening 12 colonies, three stable iPS cell lines were established.Each cell line showed human embryonic stem cell morphology and surface markers. Southern blots and polymerase chain reaction demonstrated that there was no viral DNA integration into iPS cells. Fingerprinting and karyotype analysis confirmed that these iPS cell lines are derived from the parent human fibroblasts. The three human iPS cell lines can differentiate to all three germ layers in vitro, including dopaminergic neurons. After s.c. injection into nonobese diabetic-severe combined immunodeficient mice, each human iPS line produced teratomas within 5 weeks postimplantation. We conclude that adenoviral vectors can reprogram human fibroblasts to pluripotent stem cells for use in individualized cell therapy without the risk for viral or oncogene incorporation. STEM

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