Mutations of the DJ-1 (PARK7) gene are linked to familial Parkinson's disease. We used gene targeting to generate DJ-1-deficient mice that were viable, fertile, and showed no gross anatomical or neuronal abnormalities. Dopaminergic neuron numbers in the substantia nigra and fiber densities and dopamine levels in the striatum were normal. However, DJ-1؊͞؊ mice showed hypolocomotion when subjected to amphetamine challenge and increased striatal denervation and dopaminergic neuron loss induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyrindine. DJ-1؊͞؊ embryonic cortical neurons showed increased sensitivity to oxidative, but not nonoxidative, insults. Restoration of DJ-1 expression to DJ-1؊͞؊ mice or cells via adenoviral vector delivery mitigated all phenotypes. WT mice that received adenoviral delivery of DJ-1 resisted 1-methyl-4-phenyl-1,2,3,6-tetrahydropyrindine-induced striatal damage, and neurons overexpressing DJ-1 were protected from oxidative stress in vitro. Thus, DJ-1 protects against neuronal oxidative stress, and loss of DJ-1 may lead to Parkinson's disease by conferring hypersensitivity to dopaminergic insults. P arkinson's disease (PD) is a neurodegenerative disorder characterized by tremor, rigidity, akinesia, and postural instability (1). The cause of PD remains unknown, but epidemiological and genetic studies have suggested that the observed loss of dopaminergic neurons in PD is due to defects in common intracellular signaling pathways (2). Genes linked to familial PD include ␣-synuclein (3), Parkin (4), UCH-L1 (5), PINK1 (6), and dardarin (7). Proteins encoded by these genes are thought to be involved in protein aggregation and proteasome function, processes which, when disrupted in model systems, can also result in noninherited forms of PD (8). Recently, loss-of-function mutations in the DJ-1 locus were found in families with autosomal recessive early-onset PD (9). Additional studies have confirmed other DJ-1 mutations in various PD cohorts (10). DJ-1 was initially cloned as a putative oncogene (11) and as part of an RNA-binding complex (12). DJ-1 is highly expressed by normal astrocytes (13) and has been implicated in fertilization (14) and tumorigenesis (15,16). Studies of the crystal structure of DJ-1 (17) suggest that a particular DJ-1 mutation (L166P) reduces DJ-1 protein stability (18)(19)(20), resulting in degradation through the ubiquitin-proteasome system (21, 22). However, the physiological function of DJ-1 remains largely unknown.Motor impairments in PD patients result from inhibition of the nigrostriatal motor pathway. This inhibition is due to the loss of dopaminergic neurons in the substantia nigra pars compacta (SNc) (8). The cause of the dopaminergic neuron loss remains unknown, but oxidative stress leading to apoptotic neuronal death has been implicated (23). Various neurotoxic paradigms have been studied in an effort to reproduce oxidative stress leading to neuronal loss in the SNc. Of these, administration of the well characterized meperidine analogue 1-methyl-4-phenyl-1,2,3,6-te...

Mucopolysaccharidosis type I (MPS I) is considered to represent the prototypical mucopolysaccharide storage disorder. Although a spectrum of severity is seen within the MPS I subgroup, Hurler syndrome represents the most severe and frequent manifestation of MPS I. We describe here the generation of a murine model for Hurler syndrome by targeted disruption of the murine Idua gene. Homozygous Idua -/- mice have no detectable alpha-L-iduronidase enzyme activity and show increased urinary glycosaminoglycan levels. Although normal appearing at birth, Idua -/- mice develop a flattened facial profile and thickening of the digits discernible by 3 weeks of age. No obvious growth deficiency nor mortality is seen within the first 20 weeks of life. Radiographs reveal anterior flaring of the ribs and thickening of the facial bones as early as 4 weeks of age with more extensive dysostosis detectable by 15 weeks of age. At 4 weeks of age, lysosomal storage is noted primarily within reticuloendothelial cells with abundant lysosomes noted in Kupffer cells, splenic sinusoidal lining cells, and glial cells. More widespread lysosomal storage is noted by 8 weeks of age in hepatocytes, chondrocytes, neurons, as well as renal tubular cells. Thus, targeted disruption of the murine Idua locus has produced a murine strain representative of the severe form of MPS I. This model should permit detailed evaluation of the pathophysiology of lysosomal storage disorders and provide a small animal model for the testing and development of enzyme replacement and gene therapy regimes.

cose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are incretin hormones that play important roles in maintaining glucose homeostasis and are being actively pursued as novel therapeutic agents for diabetes. GIP is produced by dispersed enteroendocrine cells and interestingly at times is coexpressed with GLP-1. We sought to determine the factors that selectively define GIP-vs. GLP-1-expressing cells. We performed comparative immunostaining of Pax6 and Pdx1 in GIP-and GLP-1-secreting cells. We investigated whether Pax6 and Pdx1 activate the human GIP promoter in control IEC-6 cells and GIP-expressing STC-1 cells. EMSA was performed to assess the binding of these transcription factors to the GIP promoter. Pax6 and Pdx1 consistently colocalized in GIP-immunoreactive cells. Cells that coexpress GIP and GLP-1 were Pax6 and Pdx1 positive, whereas cells expressing only GLP-1 were Pax6 positive but did not express Pdx1. GIP promoter activity was enhanced in IEC-6 cells by exogenous Pax6 or Pdx1 and diminished in STC-1 cells by inhibition of endogenous Pax6 or Pdx1 by dominantnegative forms. Promoter truncation analysis revealed a major loss of promoter activity when the sequence between Ϫ184 to Ϫ145 bp was deleted. EMSA studies indicated that Pax6 and Pdx1 bind to this proximal sequence of the human GIP promoter. Our findings indicate that concomitant expression of Pax6 and Pdx1 is important for GIP expression. Our results also suggest that the presence of Pdx1 defines whether GLP-1-expressing gastrointestinal L cells also coexpress GIP. transcriptional regulation; gut; K cell; glucagon-like peptide-1; glucose-dependent insulinotropic polypeptide GLUCOSE-DEPENDENT INSULINOTROPIC POLYPEPTIDE (GIP, also known as gastric inhibitory polypeptide) and glucagon-like peptide-1 (GLP-1) are gastrointestinal hormones with pleiotropic

Proteins containing a caspase recruitment domain (CARD) play pivotal roles in signal transduction leading to apoptosis and NF-B activation and inflammation. Here we identify and characterize human and mouse CARD protein 6 (CARD6), CARD-containing proteins of unique structure. CARD6 associates with microtubules and interacts with receptor-interacting protein (RIP)-like interacting caspase-like apoptosis regulatory protein kinase (RICK), a CARD-containing member of the RIP family of protein kinases. These kinases are involved in multiple NF-B signaling pathways important for innate and adaptive immune responses. Surprisingly, the CARDs of CARD6 and RICK were not required for their interaction; instead, mutational analysis revealed that the CARD of CARD6 negatively controls the association of these molecules. CARD6 also binds to RIP1, a RIP kinase homologue that lacks a CARD but contains a C-terminal death domain. Coexpression of RICK targets CARD6 to aggresomes via a mechanism that requires the CARD of RICK. Importantly, CARD6 expression has a synergistic effect on NF-B activation induced by several independent signal transduction pathways. In summary, our results indicate that CARD6 is a regulator of NF-B activation that modulates the functions of RIP kinase family members.signal transduction ͉ immunity ͉ receptor-interacting protein kinases