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BACKGROUND Effacement of horizontal forehead lines (FHL) with onabotulinumtoxinA has not been investigated in prospective Phase 3 studies. OBJECTIVE To evaluate safety and efficacy of onabotulinumtoxinA treatment of FHL together with glabellar lines (GL). MATERIALS AND METHODS A 12-month, Phase 3 study randomized subjects with moderate-to-severe FHL and GL to onabotulinumtoxinA 40 U or placebo, distributed between the frontalis (20 U) and glabellar complex (20 U). After Day 180, subjects could receive up to 2 additional open-label onabotulinumtoxinA treatments. Efficacy was assessed using the Facial Wrinkle Scale (FWS) and Facial Line Outcomes questionnaire. RESULTS The intent-to-treat (ITT) population included 391 subjects, and the modified ITT (mITT) population (subjects with psychological impact) included 254 subjects. After 30 days, onabotulinumtoxinA significantly improved the investigator- and subject-assessed appearance of FHL severity by at least 2 FWS grades in 61.4% of ITT subjects versus 0% of placebo subjects (p < .0001). In the mITT population, 94.8% of onabotulinumtoxinA subjects and 1.7% of placebo subjects achieved investigator- and subject-assessed FWS ratings of none/mild (p = .0003). Patient-reported outcomes were consistent with FWS ratings. OnabotulinumtoxinA was well tolerated. CONCLUSION OnabotulinumtoxinA 40 U distributed between the frontalis and glabellar complex was safe and effective for treatment of moderate-to-severe FHL.

Although commonly practiced, simultaneous onabotulinumtoxinA injections to multiple facial areas have not been investigated in prospective studies.Evaluate safety and efficacy of onabotulinumtoxinA for treatment of forehead lines (FHL) distributed between the frontalis (20 U) and glabellar complex (20 U), with or without simultaneous lateral canthal areas (crow's feet lines [CFL], 24 U) treatment.Subjects with moderate to severe FHL were randomized (2:2:1) to onabotulinumtoxinA 40 U, onabotulinumtoxinA 64 U, or placebo. After 180 days, subjects could receive up to 2 additional open-label onabotulinumtoxinA 64 U treatments.The intent-to-treat (ITT) population comprised 787 subjects, and the modified ITT (mITT) population (subjects with psychological impact) comprised 568. After 30 days, onabotulinumtoxinA 40 U and 64 U significantly improved investigator- and subject-assessed FHL severity by at least 2 Facial Wrinkle Scale (FWS) grades in 45.6% and 53.0% of ITT subjects, respectively, versus 0.6% receiving placebo (both, p.0001). Significantly more mITT subjects receiving onabotulinumtoxinA achieved investigator- and subject-assessed FWS ratings of none/mild versus placebo (p.0001). OnabotulinumtoxinA was well tolerated.OnabotulinumtoxinA distributed between the frontalis and glabellar complex, with or without additional CFL injections, was safe and effective for treatment of moderate to severe FHL.

1-Methyl-4-phenylpyridinium (MPP(+)), the active metabolite of the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, selectively kills dopaminergic neurons in vivo and in vitro via a variety of toxic mechanisms, including mitochondrial dysfunction, generation of peroxynitrite, induction of apoptosis, and oxidative stress due to disruption of vesicular dopamine (DA) storage. To investigate the effects of acute MPP(+) exposure on neuronal DA homeostasis, we measured stimulation-dependent DA release and non-exocytotic DA efflux from mouse striatal slices and extracellular, intracellular, and cytosolic DA (DAcyt) levels in cultured mouse ventral midbrain neurons. In acute striatal slices, MPP(+) exposure gradually decreased stimulation-dependent DA release, followed by massive DA efflux that was dependent on MPP(+) concentration, temperature, and DA uptake transporter activity. Similarly, in mouse midbrain neuronal cultures, MPP(+) depleted vesicular DA storage accompanied by an elevation of cytosolic and extracellular DA levels. In neuronal cell bodies, increased DAcyt was not due to transmitter leakage from synaptic vesicles but rather to competitive MPP(+)-dependent inhibition of monoamine oxidase activity. Accordingly, monoamine oxidase blockers pargyline and l-deprenyl had no effect on DAcyt levels in MPP(+)-treated cells and produced only a moderate effect on the survival of dopaminergic neurons treated with the toxin. In contrast, depletion of intracellular DA by blocking neurotransmitter synthesis resulted in ∼30% reduction of MPP(+)-mediated toxicity, whereas overexpression of VMAT2 completely rescued dopaminergic neurons. These results demonstrate the utility of comprehensive analysis of DA metabolism using various electrochemical methods and reveal the complexity of the effects of MPP(+) on neuronal DA homeostasis and neurotoxicity.

This biography of Clarence Samuel Stein comprehensively examines his built and unbuilt projects and his intellectual legacy as a proponent of the “Garden City” for a modern age. This examination of Stein's life and legacy focuses on four critical themes: his collaborative ethic in envisioning policy, design, and development solutions; promotion and implementation of “investment housing;” his revolutionary approach to community design, as epitomized in the Radburn Idea; and his advocacy of communitarian regionalism. His cutting-edge projects such as Sunnyside Gardens in New York City; Baldwin Hills Village in Los Angeles; and Radburn, New Jersey, his “town for the motor age,” continue to inspire community designers and planners in the United States and around the world. Stein was among the first architects to integrate new design solutions and support facilities into large-scale projects intended primarily to house working-class people, and he was a cofounder of the Regional Planning Association of America. As a planner, designer, and, at times, financier of new housing developments, Stein wrestled with the challenges of creating what today we would term “livable,” “walkable,” and “green” communities during the ascendency of the automobile. He managed these challenges by partnering private capital with government funding, as well as by collaborating with colleagues in planning, architecture, real estate, and politics.

This chapter focuses on Clarence Samuel Stein's collaborative approach to community design with a specific focus on the formation and initiatives of the Regional Planning Association of America (RPAA). It first provides an overview of Stein's early connections in housing policy and regionalism, along with his marriage to Aline MacMahon, before turning to the RPAA, conceived by Stein to address housing policy, community design, and regional planning, with the goal of building a Garden City. It also examines the City Housing Corporation's (CHC) community building and design strategy as well as its innovations in mortgage financing; the New York Housing and Regional Planning Commission's (HRPC) advocacy of a comprehensive housing program; the RPAA's participation in the 1925 International Town Planning Conference (ITPC) held in New York City; and the inception of the Radburn Idea. The chapter concludes with an assessment of Stein's advocacy of communitarian regionalism and metropolitanism and the CHC's demise during the 1930s.

This chapter focuses on Clarence Samuel Stein's contributions as a houser lending consistent support for a government role in order to more effectively engage the private sector while charting his transition to promoting investment housing as a preferable alternative to public housing. Stein and his colleagues enthusiastically welcomed the election of Franklin D. Roosevelt as an unprecedented opportunity to advance regionalism, new town planning, and worker housing. As a community architect, Stein favored a particular type of assisted housing—“investment housing”—a comprehensive design, development, and management approach to ensure the project's ongoing sustainability at affordable rates. This chapter first considers Stein's Hillside Homes project in New York before discussing the Resettlement Administration's Greenbelt Town program. It also examines Stein's role as consulting architect for the Baldwin Hills Village in Los Angeles.

This book documents the life and work of Clarence Samuel Stein, an environmental designer, humanist, houser, policymaker, town planner, and regionalist whose influential career stretched from the Progressive era of urban reform through the post–World War II era of postcolonial international planning. Looking through the lens of Stein's lifework, the book explores emerging concepts in site design, housing finance and management, town building, regional development, and community planning. It considers four critical themes that informed Stein's career and legacy: his collaborative approach, promotion and implementation of “investment housing,” distinctive interrelated community design epitomized as the Radburn Idea, and his advocacy of communitarian regionalism. These themes are tied together by the concept of the Garden City as introduced by Ebenezer Howard and implemented first most notably by architects Raymond Unwin and Barry Parker. This introduction provides an overview of Stein's projects and initiatives as well as the chapters that follow.

This chapter considers Clarence Samuel Stein's legacy as a community architect, along with his postwar engagement in international initiatives in town planning. In the years after World War II, Stein found himself turning his attention toward international translations of his new town ideas. Communications with international architects, housers, and planners characterized this period, with a focus on specific projects, such as the new towns of Chandigarh in India and Stevenage in Great Britain, and broader community building concepts with housing and planning experts in places as diverse as Sweden and Israel. This chapter discusses Stein's travels in Europe to new towns as he completed documentation of his own visionary work in what would become Toward New Towns for America. It also describes Stein's involvement in town building projects in India and Israel and concludes with an assessment of his legacy in the areas of investment housing and communitarian regionalism and the influence of his community building concepts ranging from the Regional City to the Radburn Idea.

This chapter focuses on Clarence Samuel Stein's formative years, including the foundations of his work ethic, engagement in learning by doing, community design skills, and commitment to affordable housing. Born in Rochester, New York, on June 19, 1882, into an upwardly mobile Jewish family, Clarence Samuel Stein was the third child of Rose Rosenblatt and Leo Stein. When the Stein Manufacturing Company consolidated with two other firms in 1890 to form the National Casket Company, the Stein family moved to the Chelsea district in New York City. This chapter first provides an overview of New York City's Ethical Culture Society and its influence on Stein's early life before discussing his enrollment in 1905 at Paris's École des Beaux Arts, known for its strong tradition of architectural education with a focus on fostering excellence in design and drafting. It also considers Stein's employment in the office of Bertram Grosvenor Goodhue as well as his civic reform work in New York City.

This chapter focuses on Clarence Samuel Stein's postwar concept of the Regional City as well as the maturation of his town planning ideas. Stein and his colleagues began to regularly use the term Regional City in 1927. Their early conception envisioned an amalgam of the romanticized medieval village with connections to the land combined with all the conveniences offered through new technologies to enhance modern lifestyles in distinctive, relatively small towns. Stein, together with MacKaye and Mumford, advocated for regional, even national, planning based on the ideas the Regional Planning Association of America (RPAA) had already promoted, including regional river basin planning, the townless highways, and state planning. This chapter considers Stein's postwar advocacy of communitarian regionalism and the rebirth of the RPAA as the Regional Development Council of America (RDCA). It also examines how Stein applied his collaborative regionalist and town planning ideals in a concrete project at Kitimat in Canada.

This chapter provides context for Clarence Samuel Stein's engagement with and translation of Ebenezer Howard's proposed Garden City and for his advocacy of these ideas in his projects, service, writings, lectures, and consulting activities throughout his career. Stein promoted Garden City as an “ideal system” for neighborhood preservation, housing reform, traffic congestion mitigation, and park design. What struck Stein about the Garden City—rechristened Regional City—was its spirit of cooperation and community, the balance between open spaces and development, and the notion that distinctive planned new towns served as the building blocks of the region. This chapter reviews the Garden City concept with a focus on its adoption and evolution in the United States during the first half of the twentieth century. It also considers the initiatives of the Regional Planning Association of America (RPAA), where Stein served as founder and informal sponsor, including the Radburn Idea.

This chapter examines Clarence Samuel Stein's interrelated community design, with particular emphasis on his Radburn Idea. It first takes a look at Stein's early large-scale unbuilt projects that demonstrate his emerging talent in site design, such as Sunnyside Park in Shelton, Connecticut, with Kohn in 1920; Fort Sheridan Gardens with Ernest Gruensfeldt; and the Spuyten Duyvil Housing Development in the northwest Bronx in 1923. It then considers Stein's development of Radburn to illustrate the benefits of communitarian regionalism: Radburn was conceived as a “complete town” for twenty-five thousand that would include “all the other facilities and conveniences which go to make for comfortable, pleasant living.” The chapter also discusses Stein's innovations in site design at Chatham Village in Pennsylvania; his design of Phipps Garden Apartments in New York City and the Wichita Art Institute; and his partnership with John W. Harris for the new town of Maplewood near Lake Charles, Louisiana.

The heterogeneity of multiple sclerosis (MS) characteristics among various ethnic minority populations is a topic of recent interest. However, these populations are consistently underrepresented in clinical trials, leading to limited data on the effectiveness of treatments in these groups of patients and lack of an evidence-based approach to treatment. In order to achieve optimal disease management in the ethnic minority MS populations, a better understanding of the regional, socioeconomic, and cultural influences that result in underrepresentation of these groups in clinical trials is needed. Furthermore, it would be beneficial to identify the genetic factors that influence disease disparity in these minority populations. Suggestions for the identification and implementation of best practices for fostering the trust of ethnic minority patients with MS and enhancing their participation in clinical trials are offered.

α-Synuclein (α-syn), a protein implicated in Parkinson's disease pathogenesis, is a presynaptic protein suggested to regulate transmitter release. We explored how α-syn overexpression in PC12 and chromaffin cells, which exhibit low endogenous α-syn levels relative to neurons, affects catecholamine release. Overexpression of wild-type or A30P mutant α-syn in PC12 cell lines inhibited evoked catecholamine release without altering calcium threshold or cooperativity of release. Electron micrographs revealed that vesicular pools were not reduced but that, on the contrary, a marked accumulation of morphologically “docked” vesicles was apparent in the α-syn-overexpressing lines. We used amperometric recordings from chromaffin cells derived from mice that overexpress A30P or wild-type (WT) α-syn, as well as chromaffin cells from control and α-syn null mice, to determine whether the filling of vesicles with the transmitter was altered. The quantal size and shape characteristics of amperometric events were identical for all mouse lines, suggesting that overexpression of WT or mutant α-syn did not affect vesicular transmitter accumulation or the kinetics of vesicle fusion. The frequency and number of exocytotic events per stimulus, however, was lower for both WT and A30P α-syn-overexpressing cells. The α-syn-overexpressing cells exhibited reduced depression of evoked release in response to repeated stimuli, consistent with a smaller population of readily releasable vesicles. We conclude that α-syn overexpression inhibits a vesicle “priming” step, after secretory vesicle trafficking to “docking” sites but before calcium-dependent vesicle membrane fusion.

Human α-synuclein was identified on the basis of proteolytic fragments derived from senile plaques of Alzheimer's disease, and it is the locus of mutations in some familial forms of Parkinson's disease. Its normal function and whether it may play a direct role in neural degeneration remain unknown. To explore cellular responses to neural degeneration in the dopamine neurons of the substantia nigra, we have developed a rodent model of apoptotic death induced by developmental injury to their target, the striatum. We find by mRNA differential display that synuclein is up-regulated in this model, and thus it provides an opportunity to examine directly whether synuclein plays a role in the death of these neurons or, alternatively, in compensatory responses. Up-regulation of mRNA is associated with an increase in the number of neuronal profiles immunostained for synuclein protein. At a cellular level, synuclein is almost exclusively expressed in normal neurons, rather than apoptotic profiles. Synuclein is up-regulated throughout normal postnatal development of substantia nigra neurons, but it is not further up-regulated during periods of natural cell death. We conclude that up-regulation of synuclein in the target injury model is unlikely to mediate apoptotic death and propose that it may be due to a compensatory response in neurons destined to survive.

Proteasomal dysfunction has been recently implicated in the pathogenesis of several neurodegenerative diseases, including Parkinson's disease and diffuse Lewy body disease. We have developed an in vitro model of proteasomal dysfunction by applying pharmacological inhibitors of the proteasome, lactacystin or ZIE[O-tBu]-A-leucinal (PSI), to dopaminergic PC12 cells. Proteasomal inhibition caused a dose-dependent increase in death of both naive and neuronally differentiated PC12 cells, which could be prevented by caspase inhibition or CPT-cAMP. A percentage of the surviving cells contained discrete cytoplasmic ubiquitinated inclusions, some of which also contained synuclein-1, the rat homologue of human alpha-synuclein. However the total level of synuclein-1 was not altered by proteasomal inhibition. The ubiquitinated inclusions were present only within surviving cells, and their number was increased if cell death was prevented. We have thus replicated, in this model system, the two cardinal pathological features of Lewy body diseases, neuronal death and the formation of cytoplasmic ubiquitinated inclusions. Our findings suggest that inclusion body formation and cell death may be dissociated from one another.

Alpha-synuclein mutations have been identified in certain families with Parkinson's disease (PD), and alpha-synuclein is a major component of Lewy bodies. Other genetic data indicate that the ubiquitin-dependent proteolytic system is involved in PD pathogenesis. We have generated stable PC12 cell lines expressing wild-type or A53T mutant human alpha-synuclein. Lines expressing mutant but not wild-type alpha-synuclein show: (1) disruption of the ubiquitin-dependent proteolytic system, manifested by small cytoplasmic ubiquitinated aggregates and by an increase in polyubiquitinated proteins; (2) enhanced baseline nonapoptotic death; (3) marked accumulation of autophagic-vesicular structures; (4) impairment of lysosomal hydrolysis and proteasomal function; and (5) loss of catecholamine-secreting dense core granules and an absence of depolarization-induced dopamine release. Such findings raise the possibility that the primary abnormality in these cells may involve one or more deficits in the lysosomal and/or proteasomal degradation pathways, which in turn lead to loss of dopaminergic capacity and, ultimately, to death. These cells may serve as a model to study the effects of aberrant alpha-synuclein on dopaminergic cell function and survival.

In hereditary Huntington's disease, a triplet repeat disease, there is extensive loss of striatal neurons. It has been shown that brain-derived neurotrophic factor (BDNF) protects striatal neurons against a variety of insults. We confirmed that BDNF enhances survival and DARPP-32 expression in primary striatal cultures derived from postnatal mice. Furthermore, BDNF inhibited intracellular oxyradical stress triggered by dopamine, and partially blocked basal and dopamine-induced apoptosis. Nevertheless, BDNF failed to rescue striatal neurons from dopamine-induced cell death. Therefore, BDNF inhibits free radical and apoptotic pathways in medium spiny neurons, but does so downstream from the point of commitment to cell death.

Cytochrome P4501A1 (CYP1A1) has been implicated in the conversion of numerous polycyclic aromatic hydrocarbons into electrophilic species capable of binding covalently to DNA and has therefore been postulated to be involved in the initiation of carcinogenesis. The expression of CYP1A1 protein appears not to be constitutive, but is readily inducible by aryl hydrocarbon (Ah) receptor ligands in a majority of tissues of experimental animals, especially the liver. To date, there is conflicting evidence for the expression or inducibility of CYP1A1 protein in human liver. In this present study, we report the detection of CYP1A1 in all 20 human liver microsomal samples tested by standard western immunoblotting with chemiluminescent detection using a specific monoclonal antibody (mAb 1-12-3) directed against a marine fish (scup) cytochrome P450E. mAb 1-12-3 has been shown previously to specifically recognize CYP1A1 in mammals. This system consistently demonstrated a detection sensitivity as low as 0.01-0.025 pmol CYP1A1 per lane. In the samples where CYP1A1 protein levels were quantitated, CYP1A1 ranged from approximately 0.4 to 5 pmol CYP1A1/mg microsomal protein. Additionally, the inducibility of CYP1A1 protein was demonstrated by incubating precision-cut human liver slices in dynamic organ culture for up to 96 h in the presence of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The specificity of mAb 1-12-3 was tested using several purified human and rat cytochrome P450s to ensure that the protein being detected was CYP1A1. mAb 1-12-3 did not cross-react with human CYP1A2 or CYP3A4 or rat CYP1B1, but did strongly recognize CYP1A1. However, there was a very weak cross-reactivity of mAb 1-12-3 with human CYP2E1, approximately 75-fold less compared with CYP1A1. In order to confirm CYP1A1 as the immunoreactive protein detected in human liver, microsomal samples were subjected to two-dimensional electrophoresis involving isoelectric focusing followed by SDS-PAGE and immunoblotting. Utilizing mAb 1-12-3, the human liver microsomal samples displayed an immunoblotting profile matching that obtained from a microsomal preparation from a AHH-1 TK+/- cell line expressing solely human CYP1A1 and differing from the profile obtained using a polyclonal antibody directed against CYP2E1 and cells expressing CYP2E1. Furthermore, mAb 1-12-3 recognized only one protein of identical mobility on the two-dimensional blots from human liver microsomes and AHH-1 TK+/- cells expressing CYP1A1, while displaying no reaction to cells expressing only CYP2E1. In conclusion, CYP1A1 appears to be expressed in human liver at low levels and is inducible upon exposure to TCDD.

The basis for selective death of specific neuronal populations in neurodegenerative diseases remains unclear. Parkinson's disease (PD) is a synucleinopathy characterized by a preferential loss of dopaminergic neurons in the substantia nigra (SN), whereas neurons of the ventral tegmental area (VTA) are spared. Using intracellular patch electrochemistry to directly measure cytosolic dopamine (DA(cyt)) in cultured midbrain neurons, we confirm that elevated DA(cyt) and its metabolites are neurotoxic and that genetic and pharmacological interventions that decrease DA(cyt) provide neuroprotection. L-DOPA increased DA(cyt) in SN neurons to levels 2- to 3-fold higher than in VTA neurons, a response dependent on dihydropyridine-sensitive Ca2+ channels, resulting in greater susceptibility of SN neurons to L-DOPA-induced neurotoxicity. DA(cyt) was not altered by alpha-synuclein deletion, although dopaminergic neurons lacking alpha-synuclein were resistant to L-DOPA-induced cell death. Thus, an interaction between Ca2+, DA(cyt), and alpha-synuclein may underlie the susceptibility of SN neurons in PD, suggesting multiple therapeutic targets.

Glial cell line-derived neurotrophic factor (GDNF) has shown robust neuroprotective and neuroreparative activities in various animal models of Parkinson's Disease or amyotrophic lateral sclerosis (ALS). The successful use of GDNF as a therapeutic in humans, however, appears to have been hindered by its poor bioavailability to target neurons in the central nervous system (CNS). To improve delivery of exogenous GDNF protein to CNS motor neurons, we employed chemical conjugation techniques to link recombinant human GDNF to the neuronal binding fragment of tetanus toxin (tetanus toxin fragment C, or TTC). The predominant species present in the purified conjugate sample, GDNF:TTC, had a molecular weight of approximately 80 kDa as determined by non-reducing SDS-PAGE. Like GDNF, addition of GDNF:TTC to culture media of neuroblastoma cells expressing GFRα-1/c-RET produced a dose-dependent increase in cellular phospho-c-RET levels. Treatment of cultured midbrain dopaminergic neurons with either GDNF or the conjugate similarly promoted both DA neuron survival and neurite outgrowth. However, in contrast to mice treated with GDNF by intramuscular injection, mice receiving GDNF:TTC revealed intense GDNF immunostaining associated with spinal cord motor neurons in fixed tissue sections. That GDNF:TTC provided neuroprotection of axotomized motor neurons in neonatal rats further revealed that the conjugate retained its GDNF activity in vivo. These results indicate that TTC can serve as a non-viral vehicle to substantially improve the delivery of functionally active growth factors to motor neurons in the mammalian CNS.

Methamphetamine (METH) selectively injures the neurites of dopamine (DA) neurons, generally without inducing cell death. It has been proposed that METH-induced redistribution of DA from the vesicular storage pool to the cytoplasm, where DA can oxidize to produce quinones and additional reactive oxygen species, may account for this selective neurotoxicity. To test this hypothesis, we used mice heterozygous (+/-) or homozygous (-/-) for the brain vesicular monoamine uptake transporter VMAT2, which mediates the accumulation of cytosolic DA into synaptic vesicles. In postnatal ventral midbrain neuronal cultures derived from these mice, METH-induced degeneration of DA neurites and accumulation of oxyradicals, including metabolites of oxidized DA, varied inversely with VMAT2 expression. METH administration also promoted the synthesis of DA via upregulation of tyrosine hydroxylase activity, resulting in an elevation of cytosolic DA even in the absence of vesicular sequestration. Electron microscopy and fluorescent labeling confirmed that METH promoted the formation of autophagic granules, particularly in neuronal varicosities and, ultimately, within cell bodies of dopaminergic neurons. Therefore, we propose that METH neurotoxicity results from the induction of a specific cellular pathway that is activated when DA cannot be effectively sequestered in synaptic vesicles, thereby producing oxyradical stress, autophagy, and neurite degeneration.

Parkinson's disease (PD) is most commonly a sporadic illness, and is characterized by degeneration of substantia nigra dopamine (DA) neurons and abnormal cytoplasmic aggregates of alpha-synuclein. Rarely, PD may be caused by missense mutations in alpha-synuclein. MPTP, a neurotoxin that inhibits mitochondrial complex I, is a prototype for an environmental cause of PD because it produces a pattern of DA neurodegeneration that closely resembles the neuropathology of PD. Here we show that alpha-synuclein null mice display striking resistance to MPTP-induced degeneration of DA neurons and DA release, and this resistance appears to result from an inability of the toxin to inhibit complex I. Contrary to predictions from in vitro data, this resistance is not due to abnormalities of the DA transporter, which appears to function normally in alpha-synuclein null mice. Our results suggest that some genetic and environmental factors that increase susceptibility to PD may interact with a common molecular pathway, and represent the first demonstration that normal alpha-synuclein function may be important to DA neuron viability. ispartof: Proceedings of the National Academy of Sciences of the United States of America vol:99 issue:22 pages:14524-9 ispartof: location:United States status: published

Melanin, the pigment in hair, skin, eyes, and feathers, protects external tissue from damage by UV light. In contrast, neuromelanin (NM) is found in deep brain regions, specifically in loci that degenerate in Parkinson's disease. Although this distribution suggests a role for NM in Parkinson's disease neurodegeneration, the biosynthesis and function of NM have eluded characterization because of lack of an experimental system. We induced NM in rat substantia nigra and PC12 cell cultures by exposure to l -dihydroxyphenylalanine, which is rapidly converted to dopamine (DA) in the cytosol. This pigment was identical to human NM as assessed by paramagnetic resonance and was localized in double membrane autophagic vacuoles identical to NM granules of human substantia nigra. NM synthesis was abolished by adenoviral-mediated overexpression of the synaptic vesicle catecholamine transporter VMAT2, which decreases cytosolic DA by increasing vesicular accumulation of neurotransmitter. The NM is in a stable complex with ferric iron, and NM synthesis was inhibited by the iron chelator desferrioxamine, indicating that cytosolic DA and dihydroxyphenylalanine are oxidized by iron-mediated catalysis to membrane-impermeant quinones and semiquinones. NM synthesis thus results from excess cytosolic catecholamines not accumulated into synaptic vesicles. The permanent accumulation of excess catechols, quinones, and catechol adducts into a membrane-impermeant substance trapped in organelles may provide an antioxidant mechanism for catecholamine neurons. However, NM in organelles associated with secretory pathways may interfere with signaling, as it delays stimulated neurite outgrowth in PC12 cells.

While the transporters that accumulate classical neurotransmitters in synaptic vesicles have been identified, little is known about how their expression regulates synaptic transmission. We have used adenoviral-mediated transfection to increase expression of the brain vesicular monoamine transporter VMAT2 and presynaptic amperometric recordings to characterize the effects on quantal release. In presynaptic axonal varicosities of ventral midbrain neurons in postnatal culture, VMAT2 overexpression in small synaptic vesicles increased both quantal size and frequency, consistent with the recruitment of synaptic vesicles that do not normally release dopamine. This was confirmed using noncatecholaminergic AtT-20 cells, in which VMAT2 expression induced the quantal release of dopamine. The ability to increase quantal size in vesicles that were already competent for dopamine release was shown in PC12 cells, in which VMAT2 expression increased the quantal size but not the number of release events. These results demonstrate that vesicle transporters limit the rate of transmitter accumulation and can alter synaptic strength through two distinct mechanisms.

Utilizing a human beta-actin promoter, a catalase cDNA expression vector was constructed. This construct was used to transfect two immortal cell lines, mouse alpha TN4-1 and rabbit N/N 1003A. The catalase activity was increased about 3.4 fold in the alpha TN4-1 cells and 38 fold in the N/N 1003A cells. Some changes in other enzyme activities were also observed as a result of the transfections. Surprisingly, the ability to degrade H2O2 in the extracellular environment of the cells did not markedly change as a result of the catalase amplification. However, the ability to resist H2O2 stress was dramatically altered. Non-protein thiol (NP-SH) levels, choline uptake and glyceraldehyde phosphate dehydrogenase (GPD) activity were all markedly decreased in the non-transfected cells when they were subjected to 300 microM H2O2. However, in both transfected cell lines, these parameters remained in the normal range during H2O2 stress. The results obtained upon observing aspects of DNA metabolism were more complicated. While on H2O2 stress, non-transfected cell lines showed a marked decrease in thymidine incorporation, only the transfected alpha TN4-1 line remained in the normal range. Thymidine incorporation in transfected rabbit N/N 1003A cells was decreased compared to normal cells. In contrast, studies on single strand DNA breaks indicated that transfected rabbit cells had little damage compared to the significant DNA damage observed in the normal cells. The normal N/N 1003A cells were also much more susceptible to H2O2 induced damage than normal alpha TN4-1 cells, suggesting that the high GSH peroxidase activity observed in the rabbit cells may be detrimental since the low glutathione reductase activity in such cells results in an accelerated depletion of glutathione. The overall results suggest that augmenting lens catalase may prevent cataract development caused by H2O2 stress.

Regulation of MAP1B expression and phosphorylation is thought to play an important role in neuronal development, particularly with regard to axon growth. The present work utilizes a novel PC12 cell variant [26] which exhibits many of the early morphological features of neurite outgrowth when stimulated with manganese chloride. Expression of MAP1B was determined by immunoblots and phosphorylation was assessed by metabolic radiolabeling with [32P]orthophosphate or with a phospho-specific antibody. The results indicate that MAP1B protein levels rise within 12 to 24 h, but there is no significant change in the phosphorylation of MAP1B. The latter conclusion is based on (i) experiments utilizing SMI 31, a monoclonal antibody that specifically reacts with phospho-MAP1B and (ii) assessments of both MAP1B phosphorylation and MAP1B protein within that same isloated protein band on Western blots. Thus, manganese increases MAP1B expression without affecting its relative phosphorylation. Although manganese does not cause neurite formation in the parental PC12 cell line, manganese is capable of inducing transient neurite regeneration from NGF-primed cells. These studies provide further evidence that the onset of neurite outgrowth may proceed without increased phosphorylation of MAP1B. During sustained neurite regeneration, however, NGF increases phosphate incorporation into MAP1B. Based on all of these findings, we conclude that early phases of neurite outgrowth (cell spreading and formation of short tapered extensions) do not necessarily require elevated phosphorylation of MAP1B.

Huntington’s disease (HD) is caused by an expanded CAG repeat in exon 1 of the gene coding for the huntingtin protein. The cellular pathway by which this mutation induces HD remains unknown, although alterations in protein degradation are involved. To study intrinsic cellular mechanisms linked to the mutation, we examined dissociated postnatally derived cultures of striatal neurons from transgenic mice expressing exon 1 of the human HD gene carrying a CAG repeat expansion. While there was no difference in cell death between wild-type and mutant littermate-derived cultures, the mutant striatal neurons exhibited elevated cell death following a single exposure to a neurotoxic concentration of dopamine. The mutant neurons exposed to dopamine also exhibited lysosome-associated responses including induction of autophagic granules and electron-dense lysosomes. The autophagic/lysosomal compartments co-localized with high levels of oxygen radicals in living neurons, and ubiquitin. The results suggest that the combination of mutant huntingtin and a source of oxyradical stress (provided in this case by dopamine) induces autophagy and may underlie the selective cell death characteristic of HD.