Parkinson's disease (PD), primarily caused by selective degeneration of midbrain dopamine (mDA) neurons, is the most prevalent movement disorder, affecting 1-2% of the global population over the age of 65. Currently available pharmacological treatments are largely symptomatic and lose their efficacy over time with accompanying severe side effects such as dyskinesia. Thus, there is an unmet clinical need to develop mechanism-based and/or diseasemodifying treatments. Based on the unique dual role of the nuclear orphan receptor Nurr1 for development and maintenance of mDA neurons and their protection from inflammation-induced death, we hypothesize that Nurr1 can be a molecular target for neuroprotective therapeutic development for PD. Here we show successful identification of Nurr1 agonists sharing an identical chemical scaffold, 4-amino-7-chloroquinoline, suggesting a critical structure-activity relationship. In particular, we found that two antimalarial drugs, amodiaquine and chloroquine stimulate the transcriptional function of Nurr1 through physical interaction with its ligand binding domain (LBD). Remarkably, these compounds were able to enhance the contrasting dual functions of Nurr1 by further increasing transcriptional activation of mDA-specific genes and further enhancing transrepression of neurotoxic proinflammatory gene expression in microglia. Importantly, these compounds significantly improved behavioral deficits in 6-hydroxydopamine lesioned rat model of PD without any detectable signs of dyskinesia-like behavior. These findings offer proof of principle that small molecules targeting the Nurr1 LBD can be used as a mechanismbased and neuroprotective strategy for PD.P D is primarily caused by selective degeneration of midbrain dopamine (mDA) neurons and is the most prevalent movement disorder, affecting 1-2% of the global population over the age of 65 (1-3). Currently available pharmacological treatments [e.g., L-3,4-dihydroxyphenylalanine (L-DOPA)] are largely symptomatic and lose their efficacy over time, with accompanying severe side effects such as dyskinesia. Thus, there is an unmet clinical need to develop mechanism-based and/or disease-modifying treatments (2, 3).During the last two decades, many intrinsic signals and extrinsic transcription factors have been identified to play critical roles for mDA neuron development (4-6). In particular, development of mDA neurons is dependent on two major signaling molecules, Sonic hedgehog (Shh) and wingless-type MMTV integration site family, member 1 (Wnt1), and their downstream factors. These two critical pathways (i.e., Shh-FoxA2 and Wnt1-Lmx1a) merge to control the expression of the orphan nuclear receptor related 1 protein (Nurr1) (7), suggesting that Nurr1 is a key regulator of mDA neurons. Indeed, Nurr1 [also known as nuclear receptor subfamily 4, group A, member 2 (NR4A2)] is essential not only for development (8-10) but also for maintenance of mDA neurons in adult brains (11). In addition, a recent study demonstrated that Nurr1 plays critical roles ...

The functional roles of the orphan nuclear receptor, Nurr1, have been extensively studied and well established in the development and survival of midbrain dopamine neurons. Since Nurr1 and other NR4A members are widely expressed in the brain in overlapping and distinct manners, it has been an open question whether Nurr1 has important function(s) in other brain areas. Recent studies suggest that up-regulation of Nurr1 expression is critical for cognitive functions and/or long-term memory in forebrain areas including hippocampal formation. Questions remain about the association between Nurr1 expression and Alzheimer’s disease (AD) brain pathology. Here, using our newly developed Nurr1-selective antibody, we report that Nurr1 protein is prominently expressed in brain areas with Aβ accumulation, i.e., the subiculum and the frontal cortex, in the 5XFAD mouse and that Nurr1 is highly co-expressed with Aβ at early stages. Furthermore, the number of Nurr1-expressing cells significantly declines in the 5XFAD mouse in an age-dependent manner, accompanied by increased plaque deposition. Thus, our findings suggest that altered expression of Nurr1 is associated with AD progression.

Although peripheral artery disease (PAD) is a major health problem, there have been limited advances in medical therapies. In PAD patients, angiogenesis is regarded as a promising therapeutic strategy to promote new arterial vessels and improve perfusion of ischemic tissue. Autophagy plays a critical role in catabolic processes for cell survival under normal and stressful conditions and plays fundamental biological roles in various cellular functions. In the present study, we showed that autophagy in endothelial cells is important for the repair and regeneration of damaged tissues. In a hindlimb ischemia mouse model, autophagy was stimulated in endothelial cells of the quadriceps muscle, and adjacent cells proliferated and regenerated. The autophagy pathway was induced under prolonged hypoxia in endothelial cells, and autophagy increased angiogenic activities. Moreover, conditioned media from endothelial cells blocked autophagy and inhibited the proliferation of muscle cells, suggesting that autophagic stimulation in endothelial cells affects the survival of adjacent cells, such as muscle. Collectively, hypoxia/ischemia-induced autophagy angiogenesis, and the damaged tissue surrounded by neo-vessels was regenerated in an ischemia model. Therefore, we strongly suggest that stimulation of autophagy in endothelial cells may be a potent therapeutic strategy in severe vascular diseases, including PAD.

Receptor tyrosine kinase MET (c-MET) has received considerable attention as a potential target for gastric cancer (GC) therapy and a number of c-MET inhibitors have been developed. For successful drug development, proper preclinical studies especially using patient derived cancer cell lines are very important. We profiled MET and MET-related characteristics in 49 GC cell lines to utilize them as models in preclinical studies of GC. Forty-nine cell lines were analyzed for genetic, biological, and molecular status to characterize MET and MET-related molecules. Four c-MET inhibitors were tested to elucidate the dependency on MET pathway in the 49 GC cell lines. Six of 49 cell lines were MET amplified with overexpression of c-MET and p-MET. The variants of MET were not associated with c-MET expression or amplification. Hs746T showed an exon 14 deletion in conjunction with MET amplification. The cell lines were divided into 6 MET amplified, 2 c-MET overexpressed, 2 hepatocyte growth factor (HGF) overexpressed, and 39 MET-negative subgroups. Except tivantinib, the c-MET inhibitors showed higher inhibition (%) in MET amplified than in MET nonamplified cell lines that MET amplified cell lines showed MET pathway dependency. However, the c-MET overexpressed and HGF overexpressed cell lines showed moderate dependency on MET pathway. Well-characterized cell lines are very important in studying drug development. Our 49 GC cell lines had various characteristics of MET and MET-related molecules and MET pathway dependency. These provide a promising platform for development of various RTK inhibitors including c-MET inhibitors.