Parkinson's disease (PD) is a progressive neurodegenerative disorder that is characterized by the loss of dopamine neurons in the substantia nigra pars compacta, culminating in severe motor symptoms, including resting tremor, rigidity, bradykinesia, and postural instability. In addition to motor deficits, there are a variety of nonmotor symptoms associated with PD. These symptoms generally precede the onset of motor symptoms, sometimes by years, and include anosmia, problems with gastrointestinal motility, sleep disturbances, sympathetic denervation, anxiety, and depression. Previously, we have shown that mice with a 95% genetic reduction in vesicular monoamine transporter expression (VMAT2-deficient, VMAT2 LO) display progressive loss of striatal dopamine, L-DOPA-responsive motor deficits, ␣-synuclein accumulation, and nigral dopaminergic cell loss. We hypothesized that since these animals exhibit deficits in other monoamine systems (norepinephrine and serotonin), which are known to regulate some of these behaviors, the VMAT2-deficient mice may display some of the nonmotor symptoms associated with PD. Here we report that the VMAT2-deficient mice demonstrate progressive deficits in olfactory discrimination, delayed gastric emptying, altered sleep latency, anxiety-like behavior, and agedependent depressive behavior. These results suggest that the VMAT2-deficient mice may be a useful model of the nonmotor symptoms of PD. Furthermore, monoamine dysfunction may contribute to many of the nonmotor symptoms of PD, and interventions aimed at restoring monoamine function may be beneficial in treating the disease.

Key words: EGFR; NF-B; AP-1; IL-8; VEGF; PI3K; MEK; HNSCCIncreased angiogenesis is critical to tumor progression and metastasis, and we and others have shown that expression of members of the C-X-C cytokine and vascular endothelial growth factor families such as IL-8, growth regulated oncogene-1 (Gro 1) and VEGF can promote angiogenesis, tumorigenesis and metastatic tumor progression. 1-3 The expression of multiple factors with proangiogenic activity by cancer cells poses a significant obstacle to effective therapy with agents targeted toward individual factors and receptors. Identification of common mechanism(s) underlying expression of such a diversity of factors could guide the development of therapy using fewer selective agents. We previously observed that IL-8, VEGF and other cytokines are coexpressed and often vary concurrently in serum and supernatants from cell lines from different patients with head and neck squamous cell carcinoma (HNSCC), 4,5 suggesting that these factors could be regulated by common signal pathways or transcription factors.Examination of the regulatory region of many proinflammatory cytokines and proangiogenic factors reveals that they share common promoter sites for transcription factors such as nuclear factor-B (NF-B) and/or activator protein-1 (AP-1), which can be activated by injury, cytokines and growth factors. 6 We found that differences in expression of these cytokines in different cancers was often related to differences in constitutive activation of both NF-B and AP-1. 6 Inhibition of NF-B activation by expression of a dominant negative inhibitor-B or pharmacologic agents was found to inhibit expression of IL-8 and other proinflammatory and proangiogenic cytokines, 7-10 as well as tumorigenesis and angiogenesis in vivo. 7,9 Inhibition of activation of extracellular signalregulated kinase (ERK) and AP-1 with antagonists of mitogenactivated/extracellular signal-regulated kinase (MEK) partially inhibited expression of both IL-8 and VEGF. 10 These results provided evidence that at least 2 signal pathways upstream of NF-B and AP-1 make important contributions to expression of these angiogenesis factors.We have recently examined the contribution of several factors that may contribute to upstream signal activation of NF-B and AP-1 and expression of IL-8 and VEGF. We found that IL-1␣ expressed by HNSCC promotes autocrine activation of NF-B and AP-1, expression of IL-8 and cell survival. 11 Expression of IL-1 receptor antagonist inhibited NF-B reporter activity and IL-8 expression by 60 -80%, indicating that IL-1␣ is a major contributor to constitutive activation of NF-B and IL-8. HNSCC were also found to express c-MET, a receptor tyrosine kinase for hepatocyte growth factor/scatter factor (HGF/SF). 12 Increased expression of HGF/SF was detected together with IL-8 and VEGF in serum of patients with HNSCC, and recombinant HGF and HGF from stromal fibroblasts was found to further induce IL-8 and VEGF expression by human HNSCC lines. Inhibitors of MEK and Abbreviations: AP-1, activator...

Dopamine is a key neuromodulator in the retina and brain that supports motor, cognitive and visual function. Here, we developed a mouse model, on a C57 background, in which expression of the rate-limiting enzyme for dopamine synthesis, tyrosine hydroxylase, is specifically disrupted in the retina. This model enabled assessment of the overall role of retinal dopamine in vision using electrophysiological (electroretinogram), psychophysical (optokinetic tracking) and pharmacological techniques. Significant disruptions were observed in high-resolution, light-adapted vision caused by specific deficits in light responses, contrast sensitivity, acuity and circadian rhythms in this retinal dopamine-depleted mouse model. These global effects of retinal dopamine on vision are driven by the differential actions of dopamine D1 and D4 receptors on specific retinal functions and appear to be due to the ongoing bioavailability of dopamine, rather than developmental effects. Taken together, our data indicate that dopamine is necessary for the circadian nature of light-adapted vision, as well as optimal contrast detection and acuity.

SUMMARY The serotonergic raphe nuclei of the midbrain are principal centers from which serotonin neurons project to innervate cortical and sub-cortical structures. The dorsal raphe nuclei receive light input from the circadian visual system [1] and indirect input from the biological clock nuclei [2, 3]. Dysregulation of serotonin neurotransmission is implicated in neurobehavioral disorders, such as depression and anxiety [4], and alterations in the serotonergic phenotype of raphe neurons have dramatic effects on affective behaviors in rodents [5]. Here, we demonstrate that day length (photoperiod) during development induces enduring changes in mouse dorsal raphe serotonin neurons—programming their firing rate, responsiveness to noradrenergic stimulation, intrinsic electrical properties, serotonin and norepinephrine content in the midbrain, and depression/anxiety-related behavior in a melatonin receptor 1 (MT1)-dependent manner. Our results establish mechanisms by which seasonal photoperiods may dramatically and persistently alter the function of serotonin neurons.

In the mammalian retina, dopamine binding to the dopamine D4 receptor affects a light-sensitive pool of cyclic AMP by negatively coupling to the type 1 adenylyl cyclase. The type 1 adenylyl cyclase is the primary enzyme controlling cyclic AMP production in dark-adapted photoreceptors. A previous study demonstrated that expression of the gene encoding the type 1 adenylyl cyclase, Adcy1, is down regulated in mice lacking Drd4, the gene encoding the dopamine D4 receptor. The present investigation provides evidence that dopamine D4 receptor activation entrains the circadian rhythm of Adcy1 mRNA expression. Diurnal and circadian rhythms of Drd4 and Adcy1 mRNA levels were observed in wild type mouse retina. Also, rhythms in the Ca2+-stimulated adenylyl cyclase activity and cyclic AMP levels were observed. However, these rhythmic activities were damped or undetectable in mice lacking the dopamine D4 receptor. Pharmacologically activating the dopamine D4 receptor 4 hrs before its normal stimulation at light onset in the morning advances the phase of the Adcy1 mRNA expression pattern. These data demonstrate that stimulating the dopamine D4 receptor is essential in maintaining the normal rhythmic production of the type 1 adenylyl cyclase from transcript to enzyme activity. Thus, dopamine/dopamine D4 receptor signaling is a novel zeitgeber that entrains the rhythm of Adcy1 expression and, consequently, modulates the rhythmic synthesis of cyclic AMP in mouse retina.

Spatial variation in light intensity

Dopamine is a neuromodulator that influences many physiological functions in the retina (reviewed by Witkovsky 2004). It enhances cone input signals and decreases rod input signals, uncouples horizontal cell and AII amacrine cell gap junction networks, enhances contrast sensitivity, and modulates light-and dark-adaptation. Also, it has trophic actions within the retina, affecting circadian rhythms, retinal development, and ocular growth (Witkovsky 2004). Activation of dopamine receptors, particularly the dopamine D 4 receptor (D 4 R) subtype from the D 2 family of receptors, suppresses the light-sensitive pool of cyclic AMP in dark-adapted mouse photoreceptors (Cohen and Blazynski 1990;Cohen et al. 1992). Cyclic AMP levels in photoreceptor cells are highest in darkness and reduced by light exposure. Although it is known that light and D 4 R activation regulate the same pool of cyclic AMP, they appear to do so by different mechanisms. Nir et al. (2002) showed that the effect of light is not directly dependent on D 4 R activation; however, in mice lacking D 4 Rs (Drd4)/) mice), cyclic AMP levels were significantly lower in darkness and unresponsive to light when compared with wild-type controls. These observations suggested that D 4 R activation Similarly, in mice with disruption of the gene (Drd4) encoding D 4 R, cyclic AMP levels in the dark-adapted retina are significantly lower compared to wild-type retina and are unresponsive to light. These changes in Drd4)/) mice were accompanied by significantly lower Adcy1 mRNA levels in photoreceptor cells and lower Ca 2+ /calmodulin-stimulated adenylyl cyclase activity in retinal membranes compared with wild-type controls. Reduced levels of Adcy1 mRNA were also observed in retinas of wild-type mice treated chronically with a D 4 R antagonist, L-745870. Thus, activation of D 4 R is required for normal expression of AC1 and for the regulation of its catalytic activity by light. These observations illustrate a novel mechanism for cross-talk between dopamine and photic signaling pathways regulating cyclic AMP in photoreceptor cells.

Purpose: The transforming growth factor-h (TGF-h) signaling pathway has been frequently implicated in breast cancer. An intronic variant (Int7G24A) of TGF-h receptor type I (TGFBR1) is associated with kidney and bladder cancers in our recent study.We hypothesize that this germline variant may be involved in development and progression of breast cancer. Experimental Design: Case-control studies were designed from archived paraffin-embedded tissue specimens from the same geographic area with a homogenous ethnic population.We analyzed 223 patients (25 with preinvasive tumors and 198 with invasive and metastatic breast cancers) and 153 noncancer controls.The Int7G24A was identified by PCR-RFLP. Another germline deletion (TGFBR1*6A) and somatic mutations in theTGFBR1 were also analyzed by PCR and single-strand conformational polymorphism. Results: The Int7G24A allele was evident in 32% of patients with preinvasive neoplasms and 48% of patients with invasive breast cancers compared with 26% controls (P = 0.00008). In addition, 11 (5.6%) homozygous Int7G24A carriers were found in patients with invasive breast cancers, whereas only 3 (2 %) homozygous carriers were found in the control group. The TGFBR1*6A allele was not significantly associated with breast cancer patients and only one somatic mutation was found in 71breast cancers. Conclusion: These data suggest that the germline Int7G24A variant may represent a risk factor for invasive breast cancer and a marker for breast cancer progression. A separate study with alarger sample size is warranted to validate the association of the Int7G24A with human breast cancer.