NRF2 Activation Ameliorates Oxidative Stress and Improves Mitochondrial Function and Synaptic Plasticity, and in A53T α-Synuclein Hippocampal Neurons.

In Parkinson's disease (PD), brain oxidative stress and mitochondrial dysfunction contribute to neuronal loss as well as motor and cognitive deficits. The transcription factor NRF2 has emerged as a promising therapeutic target in PD because it sits at the intersection of antioxidant and mitochondrial pathways. Here, we investigate the effects of modulating NRF2 activity in neurons isolated from a A53T α-synuclein (A53TSyn) mouse model of synucleinopathy. Embryonic hippocampal neurons were isolated from A53TSyn mice and their wild type (WT) littermates. Neurons were treated with either the NRF2 activator dimethyl fumarate (DMF) or the NRF2 inhibitor ML385. Reactive oxygen species (ROS), dendritic arborization and dendritic spine density were quantified. Mitochondrial bioenergetics were also profiled in these neurons. A53TSyn neurons had increased ROS and reduced basal and maximal mitochondrial respiration relative to WT neurons. A53TSyn neurons also displayed decreased dendritic arborization and reduced spine density. Treatment with DMF reduced ROS levels and improved both mitochondrial function and arborization, while inhibition of NRF2 with ML385 exacerbated these endpoints. Modulation of NRF2 activity had a significant effect on mitochondrial function, oxidative stress, and synaptic plasticity in A53TSyn neurons. These data suggest that NRF2 may be a viable target for therapeutic interventions in PD.

Retailer licensing and tobacco display compliance: are some retailers more likely to flout regulations?

OBJECTIVES: To assess retailer compliance with a licensing scheme requiring tobacco retailers to list their business details with the government, to examine whether listed retailers are more likely to comply with a point-of-sale (POS) display ban and other in-store retailing laws and to explore variations in compliance between different retailer types and locations. METHOD: An audit of 1739 retailers in New South Wales, Australia, was used to assess compliance with tobacco retailing legislation. Auditors actively searched for and audited unlisted retailers and all listed retailers in 122 metropolitan and regional postcodes. Multivariate generalised linear regression models were used to examine associations between compliance and retailer type, remoteness and demographic characteristics (socioeconomic level, proportion of population under 18 years and proportion born in Australia). RESULTS: One unlisted tobacco retailer was identified for every 12.6 listed tobacco retailers. Unlisted retailers were significantly more likely than listed retailers to breach in-store retailing laws (p<0.001). Compliance with the POS display ban was observed in 91.3% of tobacco retailers, but compliance with all retailing laws was only 73.4%. Retailers in socioeconomically disadvantaged areas had lower compliance than those in high socioeconomic areas. CONCLUSIONS: Some tobacco retailers did not list their business details with the government as required, even though there was no financial cost to do so. Unlisted retailers were more likely to violate in-store regulations. The results suggest licensing schemes can be useful for providing a list of retailers, thus facilitating enforcement, but require a system to search for, and respond to, unlisted/unlicensed retailers.

The role of public health advocacy in achieving an outright ban on commercial tanning beds in Australia.

Although many countries still face opposition to the legislation of artificial tanning beds, all Australian states and territories have announced a total ban on commercial tanning beds. A combination of epidemiological and policy-centered research, powerful personal stories, and the active advocacy of prominent academics, cancer organizations, and grassroots community campaigners contributed to the decisions to first legislate standards and then ban all commercial tanning beds. We have illustrated that incremental change can be an effective pathway to securing substantial public health reforms.

Marketing cigarettes when all else is unavailable: evidence of discounting in price-sensitive neighbourhoods.

OBJECTIVE: Since price is both a key determinant of smoking and one of the few remaining marketing strategies available in countries without point-of-sale tobacco display, this study examines cigarette price variations in the Australian market and assesses whether those variations are consistent with price being used to increase or maintain smoking among price-sensitive groups. METHOD: An audit of 1739 tobacco retailers was used to collect variations in the price of the best-selling Australian cigarette brand, as well as record retailer compliance with tobacco retailing legislation. We examined variation in pricing across outlet type, demographic variations (socioeconomic level, % in the area under 18 and % born in Australia), remoteness and retailer compliance with tobacco retailing legislation. RESULTS: Multipacks were offered by 27.8% of retailers, with the average pack price in a twin pack $1.32 (or 7.3%) cheaper than a single pack. Prices were significantly lower in some outlet types, in lower socioeconomic postcodes and in those with a higher percentage of people under 18. In contrast with other consumer goods, prices were lower (although not significantly so) outside major cities. CONCLUSIONS: The provision of substantial multi-pack discounts and lower prices in postcodes with a higher proportion of price-sensitive smokers (young people and those from lower socioeconomic groups) is consistent with targeted discounts being used as a tobacco marketing strategy. The results support policy interventions to counter selective discounts and to require disclosure of trade-based discounts.

Enhancing alloreactivity does not restore GVHD induction but augments skin graft rejection by CD4⁺ effector memory T cells.

Graft-versus-host disease (GVHD) caused by donor T cells attacking recipient tissues is a major cause of morbidity and mortality following allogeneic hematopoietic stem cell transplantation (alloSCT). Studies have shown that effector memory T (T(EM) ) cells do not cause GVHD but are capable of immune functions post-transplant, including graft-versus-leukemia (GVL) effects, but the reasons for this are unclear. In mice, the T(EM) pool may have a less diverse T-cell receptor (TCR) repertoire than naive T (T(N) ) cells with fewer alloreactive clones. We therefore tested whether enhancing the alloreactivity of T(EM) cells would restore their ability to cause GVHD. In an MHC-matched system, alloreactive T(EM) cells were created by transferring GVHD effector cells into syngeneic recipients and allowing conversion to T(EM) cells. Upon retransfer to freshly transplanted recipients, these cells caused only mild GVHD. Similarly, in an MHC-mismatched system, T(EM) cells with a proven increased precursor frequency of alloreactive clones only caused limited GVHD. Nonetheless, these same cells mounted strong in vitro alloresponses and caused rapid skin graft rejection. T(EM) cells created from CD4(+) T cells that had undergone lymphopenia-induced proliferation (LIP) also caused only mild GVHD. Our findings establish that conversion to T(EM) cells significantly reduces GVHD potency, even in cells with a substantially enhanced alloreactive repertoire.

Anywhere, anytime: retail access to tobacco in New South Wales and its potential impact on consumption and quitting.

Relatively little attention has been given to the retail availability of tobacco products despite the likelihood that ubiquitous supply may represent a primary form of tobacco promotion in Australia. This study aimed to explore the number and distribution of tobacco outlets, smokers' perceptions about the availability of tobacco and the role availability may play in tobacco consumption and quitting attempts in Australia. The study comprised two parts: Part A involved mapping retail tobacco outlets in the Hunter Region of NSW, Australia. Part B involved a statewide telephone survey of 539 current smokers aged 18 years and over in NSW. Part A identified 1270 retail tobacco outlets, giving a density of one outlet per 384 persons aged over 15 years, or one outlet per 77 smokers. Associations between socioeconomic status of areas and retail availability of tobacco were not found. Of the survey respondents in Part B, 87.5% indicated that they would be within walking distance of a retail tobacco outlet during their daily activities. Those who were younger, male and single were more likely to purchase tobacco at convenience-type outlets. We therefore conclude that some groups of smokers appear vulnerable to the availability of tobacco and a reduction in the availability of tobacco is likely to benefit smokers who wish to quit.

Smoking in movies in Australia: who feels over-exposed and what level of regulation will the community accept?

OBJECTIVE: This study aimed to examine recent levels of exposure to smoking in movies, how the community perceived the level of smoking they saw in recently-viewed movies and whether there was community support for any form of regulation. METHODS: As part of a 2004 New South Wales survey of smoking-related perceptions and practices, 1,154 adults participated in a computer-assisted telephone interview about perceptions relating to smoking depiction in movies and television. RESULTS: More than one-quarter of those who had seen a recent movie in the cinema (28.5%) or on DVD (33.9%) thought that the movie contained excessive or inappropriate smoking. More than half the sample (59.1%) considered it likely the tobacco industry played a role in the level of smoking depiction, although only 18% of those who thought a recent movie contained excessive smoking attributed this to the tobacco industry. Almost two-thirds of respondents favoured screening anti-tobacco advertisements prior to movies with smoking. CONCLUSION: Cinema and DVD movies commonly include scenes where there is excessive or inappropriate smoking. It is widely believed that the tobacco industry is contributing to this, and there is strong community support for action to curb the harmful influences this may be having.

Is government action out-of-step with public opinion on tobacco control? Results of a New South Wales population survey.

OBJECTIVE: To assess community attitudes towards smoking bans, tobacco availability, promotion and product regulation, tobacco industry donations to political parties, and government spending on tobacco control activities. To compare public preferences on these issues with policies of the NSW and Commonwealth governments. METHOD: Anonymous, computer assisted telephone interviews of adults from randomly selected households in the NSW Electronic White Pages conducted in 2004. All subjects completed a core question set and subsequently, one of three sub-sets. RESULTS: Overall 49.1% of eligible subjects consented. Data from two sub-samples containing 1,191 and 1,158 subjects are reported. Majority support existed for smoking bans in all six settings assessed: children's playgrounds (89%), sports stadia (77%), licensed premises (72%), outdoor dining (69%), beaches (55%) and motor vehicles carrying children (55%). Respondents nominated vastly higher tobacco control budgets than current levels of government expenditure. On a scale assessing support for tobacco control (maximum score = 13), the mean scores of both non-smokers (10.4) and smokers (8.0) were high. Of seven variables tested, only two: living with a smoker and personal smoking status were independent predictors of having a high pro-tobacco control score. CONCLUSION: There is strong community support for additional government regulation mandating smoke-free provision and other counter tobacco measures. IMPLICATIONS: Continued advocacy campaigns are required to align government tobacco control agenda more closely with public preferences.

CTLA4 expression is an indicator and regulator of steady-state CD4+ FoxP3+ T cell homeostasis.

The presence of FoxP3(+) regulatory T cells (Tregs) is necessary for control of deleterious immune responses in the steady state; however, mechanisms for maintaining the frequency and quality of endogenous Tregs are not well defined. In this study, we used in vivo modulators of the CD28 and CTLA4 pathways administered to intact mice to reveal mechanisms controlling the homeostasis and phenotype of endogenous Tregs. We demonstrate that expression of the negative costimulatory regulator CTLA4 on FoxP3(+) Tregs in vivo is a direct consequence of their rapid, perpetual homeostasis. Up-regulation of CTLA4 expression occurs only on FoxP3(+) Tregs undergoing extensive proliferation and can be abrogated by inhibiting the CD28 pathway, coinciding with a reduction in FoxP3(+) Treg proliferation and frequency. We further demonstrate that CTLA4 negatively regulates steady-state Treg homeostasis, given that inhibiting CTLA4 signaling with an anti-CTLA4 blocking Ab greatly enhances Treg proliferation and overall Treg frequency. Our findings provide new insight into the origin and role of CTLA4 expression on natural FoxP3(+) Tregs and reveal opposing effects of costimulation modulators on the steady-state level and quality of Tregs, with implications regarding their effects on endogenous Tregs in patients receiving immunotherapy.

Core histone genes of Giardia intestinalis: genomic organization, promoter structure, and expression.

BACKGROUND: Giardia intestinalis is a protist found in freshwaters worldwide, and is the most common cause of parasitic diarrhea in humans. The phylogenetic position of this parasite is still much debated. Histones are small, highly conserved proteins that associate tightly with DNA to form chromatin within the nucleus. There are two classes of core histone genes in higher eukaryotes: DNA replication-independent histones and DNA replication-dependent ones. RESULTS: We identified two copies each of the core histone H2a, H2b and H3 genes, and three copies of the H4 gene, at separate locations on chromosomes 3, 4 and 5 within the genome of Giardia intestinalis, but no gene encoding a H1 linker histone could be recognized. The copies of each gene share extensive DNA sequence identities throughout their coding and 5' noncoding regions, which suggests these copies have arisen from relatively recent gene duplications or gene conversions. The transcription start sites are at triplet A sequences 1-27 nucleotides upstream of the translation start codon for each gene. We determined that a 50 bp region upstream from the start of the histone H4 coding region is the minimal promoter, and a highly conserved 15 bp sequence called the histone motif (him) is essential for its activity. The Giardia core histone genes are constitutively expressed at approximately equivalent levels and their mRNAs are polyadenylated. Competition gel-shift experiments suggest that a factor within the protein complex that binds him may also be a part of the protein complexes that bind other promoter elements described previously in Giardia. CONCLUSION: In contrast to other eukaryotes, the Giardia genome has only a single class of core histone genes that encode replication-independent histones. Our inability to locate a gene encoding the linker histone H1 leads us to speculate that the H1 protein may not be required for the compaction of Giardia's small and gene-rich genome.

Generation, homeostasis, and regulation of memory T cells in transplantation.

PURPOSE OF REVIEW: Sensitized individuals experience higher rates of acute rejection and decreased graft survival. Memory T cells have been implicated in these processes, and in the prevention of tolerance induction. A greater understanding of T-cell memory generation, maintenance, and regulation is needed to design new immunosuppressive strategies that prolong graft survival in the presence of alloreactive memory. RECENT FINDINGS: Memory T cells are generated against alloantigens via homologous and cross-reactive priming, and recent studies demonstrate that T-cell depletion can also paradoxically result in memory generation. While initially thought to be impervious to regulation due to their enhanced functional properties, memory T cells have shown susceptibility to certain immunomodulating therapies and immunosuppressants and, furthermore, newer targets for memory T-cell regulation show promise in controlling immunological recall. SUMMARY: Current immunosuppression protocols should be designed with consideration of their effects not only on naive T-cell activation, but also on memory generation, activation, and effector function. Additionally, research efforts should continue to identify and manipulate new costimulatory targets and immunosuppressants, which may be key to abrogating memory T-cell responses.

Reshaping the past: Strategies for modulating T-cell memory immune responses.

Memory T cells are generated following an initial encounter with antigen, persist over the lifetime of an individual, and mediate rapid and robust functional responses upon antigenic recall. While immune memory is generally associated with protective immune response to pathogens, memory T cells can be generated to diverse types of antigens including autoantigens and alloantigens through homologous or crossreactive priming and comprise the majority of circulating T cells during adulthood. Memory T cells can therefore play critical roles in propagating and perpetuating autoimmune disease and in mediating allograft rejection, although the precise pathways for regulation of memory immune responses remain largely undefined. Moreover, evaluating and designing strategies to modulate memory T-cell responses are challenging given the remarkable heterogeneity of memory T cells, with different subsets predominating in lymphoid versus non-lymphoid tissue sites. In this review, we discuss what is presently known regarding the effect of current immunomodulation strategies on the memory T-cell compartment and potential strategies for controlling immunological recall.

A novel rat model of carotid artery stenting for the understanding of restenosis in metabolic diseases.

The effects of risk modifiers such as diabetes, obesity and hypertension on vascular healing after stent deployment are largely unknown, because of a lack of an appropriate animal model to study. Since many inbred strains of rats expressing these phenotypes are available, we validated a carotid artery model of in-stent restenosis in the rat. A detailed histomorphometric analysis was performed on 2-cell Multi-Link(TM) stents (1.5 x 5 mm) deployed in the common carotid artery of male Wistar rats. Early focal thrombus formation around stent struts with adherent leukocytes was evident by day 3. The number of ED-1-positive macrophages was maximal by day 7 and declined markedly thereafter. Neointimal cell proliferation peaked by day 7 (19.3 +/- 6.9) and progressively decreased to <2% by day 60. By day 14, neointimal area was significantly increased (0.39 +/- 0.03 vs. 0.18 +/- 0.05 mm(2) at day 7, p = 0.003) characterized by an enhanced number of alpha-actin-positive smooth muscle cells surrounded by extracellular matrix rich in versican and hyaluronan. At day 28, neointimal area was maximal accompanied by an appreciable decrease in the staining intensity for hyaluronan and versican. By day 60, neointimal area decreased significantly (0.28 +/- 0.04 vs. 0.45 +/- 0.07 mm(2) at day 28, p = 0.04) independent of a change in cell density. This regression phase was accompanied by a marked increase in elastin fibrils and collagen type I. In summary, vascular healing following carotid artery stenting in the rat parallels that of larger animals; however, it is accelerated relative to humans.