Deliberating performance targets workshop: Potential paths for emerging PM2.5 and O3 air sensor progress.

The United States Environmental Protection Agency held an international two-day workshop in June 2018 to deliberate possible performance targets for non-regulatory fine particulate matter (PM2.5) and ozone (O3) air sensors. The need for a workshop arose from the lack of any market-wide manufacturer requirement for Ozone documented sensor performance evaluations, the lack of any independent third party or government-based sensor performance certification program, and uncertainty among all users as to the general usability of air sensor data. A multi-sector subject matter expert panel was assembled to facilitate an open discussion on these issues with multiple stakeholders. This summary provides an overview of the workshop purpose, key findings from the deliberations, and considerations for future actions specific to sensors. Important findings concerning PM2.5 and O3 sensors included the lack of consistent performance indicators and statistical metrics as well as highly variable data quality requirements depending on the intended use. While the workshop did not attempt to yield consensus on any topic, a key message was that a number of possible future actions would be beneficial to all stakeholders regarding sensor technologies. These included documentation of best practices, sharing quality assurance results along with sensor data, and the development of a common performance target lexicon, performance targets, and test protocols.

Preparation and Biochemical Analysis of Classical Histone Deacetylases.

Histone deacetylase assays were first developed in the 1970s, and subsequently refined in the 1990s with the cloning of HDAC enzymes. Most of these early assays, relying on traditional in vitro chemical methodologies, are still applicable today. More recently, however, cell-based HDAC assays that measure HDAC activities in physiological conditions are emerging. Also, there is a continuing development of assays that can measure an isolated HDAC in the absence of other HDAC activities. This chapter reviews some of the older established methods for assaying HDAC activities, as well as introduces more recently developed nontraditional assays.

Targeting histone deacetylase 6 mediates a dual anti-melanoma effect: Enhanced antitumor immunity and impaired cell proliferation.

The median survival for metastatic melanoma is in the realm of 8-16 months and there are few therapies that offer significant improvement in overall survival. One of the recent advances in cancer treatment focuses on epigenetic modifiers to alter the survivability and immunogenicity of cancer cells. Our group and others have previously demonstrated that pan-HDAC inhibitors induce apoptosis, cell cycle arrest and changes in the immunogenicity of melanoma cells. Here we interrogated specific HDACs which may be responsible for this effect. We found that both genetic abrogation and pharmacologic inhibition of HDAC6 decreases in vitro proliferation and induces G1 arrest of melanoma cell lines without inducing apoptosis. Moreover, targeting this molecule led to an important upregulation in the expression of tumor associated antigens and MHC class I, suggesting a potential improvement in the immunogenicity of these cells. Of note, this anti-melanoma activity was operative regardless of mutational status of the cells. These effects translated into a pronounced delay of in vivo melanoma tumor growth which was, at least in part, dependent on intact immunity as evidenced by the restoration of tumor growth after CD4+ and CD8+ depletion. Given our findings, we provide the initial rationale for the further development of selective HDAC6 inhibitors as potential therapeutic anti-melanoma agents.

Deacetylation of the tumor suppressor protein PML regulates hydrogen peroxide-induced cell death.

The promyelocytic leukemia protein (PML) is a tumor suppressor that is expressed at a low level in various cancers. Although post-translational modifications including SUMOylation, phosphorylation, and ubiquitination have been found to regulate the stability or activity of PML, little is known about the role of its acetylation in the control of cell survival. Here we demonstrate that acetylation of lysine 487 (K487) and SUMO1 conjugation of K490 at PML protein are mutually exclusive. We found that hydrogen peroxide (H2O2) promotes PML deacetylation and identified SIRT1 and SIRT5 as PML deacetylases. Both SIRT1 and SIRT5 are required for H2O2-mediated deacetylation of PML and accumulation of nuclear PML protein in HeLa cells. Knockdown of SIRT1 reduces the number of H2O2-induced PML-nuclear bodies (NBs) and increases the survival of HeLa cells. Ectopic expression of wild-type PML but not the K487R mutant rescues H2O2-induced cell death in SIRT1 knockdown cells. Furthermore, ectopic expression of wild-type SIRT5 but not a catalytic defective mutant can also restore H2O2-induced cell death in SIRT1 knockdown cells. Taken together, our findings reveal a novel regulatory mechanism in which SIRT1/SIRT5-mediated PML deacetylation plays a role in the regulation of cancer cell survival.

Epstein-Barr virus maintains lymphomas via its miRNAs.

Epstein-Barr virus (EBV) has evolved exquisite controls over its host cells, human B lymphocytes, not only directing these cells during latency to proliferate and thereby expand the pool of infected cells, but also to survive and thereby persist for the lifetime of the infected individual. Although these activities ensure the virus is successful, they also make the virus oncogenic, particularly when infected people are immunosuppressed. Here we show, strikingly, that one set of EBV's microRNAs (miRNAs) both sustain Burkitt's lymphoma (BL) cells in the absence of other viral oncogenes and promote the transformation of primary B lymphocytes. BL cells were engineered to lose EBV and found to die by apoptosis and could be rescued by constitutively expressing viral miRNAs in them. Two of these EBV miRNAs were found to target caspase 3 to inhibit apoptosis at physiological concentrations.

Myc represses miR-15a/miR-16-1 expression through recruitment of HDAC3 in mantle cell and other non-Hodgkin B-cell lymphomas.

Our recent study demonstrated miR-15a/16-1 downregulation in mantle cell lymphoma (MCL). Here, we investigated mechanisms of miR-15a/16-1 transcriptional repression and its epigenetic regulation by c-Myc and histone deacetylase (HDAC) in MCL. c-Myc expression was detected in MCL cell lines and in the primary MCL samples, and pri-miR-15a/16-1 mRNAs were significantly upregulated in Mino and Jeko-1 cells with c-Myc knockdown by small interfering RNAs (siRNAs). Our co-immunoprecipitation analysis showed that c-Myc interacted with HDAC3. Moreover, using chromatin immunoprecipitation, we demonstrated that both c-Myc and HDAC3 co-localized to the two promoters of the miR-15a/16-1 cluster gene, DLEU2, and inhibition of HDAC3 increased histone acetylation of the DLEU2 promoters. Luciferase reporter assay confirmed the dependence of Myc-mediated DLEU2 transcriptional repression on HDAC3. Treatment with the pan-HDAC inhibitor, suberoylanilide hydroxamic acid and HDAC3 siRNA resulted in increased miR-15a/16-1 expression. The regulatory mechanism of miR-15a/16-1 was further demonstrated in Burkitt lymphoma and Myc overexpressing cell lines. These findings highlight the role of HDAC3 in Myc-induced miR-15a/16-1 changes and reveal novel mechanisms for c-Myc-driven microRNA suppression and malignant transformation in aggressive B-cell malignancies.

The challenge of effective surveillance in moving from low transmission to elimination of schistosomiasis in China.

Until recently, intensified efforts in China to suppress the transmission of Schistosoma japonicum relied principally on routine praziquantel treatment, extensive use of molluscicides and health education programs. These efforts, now supplemented by a broader range of control measures, have been quite successful in reducing the prevalence and intensity of human infection to very low levels. However, re-emergent transmission has occurred in formerly endemic areas of several provinces, signalling the need for more locally effective, integrated control strategies. We argue that these low but persistent levels of transmission also require important changes in both the tactics and strategy of disease surveillance to move forward towards elimination. Here we present recent data exemplifying the low transmission environment which suggests that we are reaching limits of detection of current diagnostic techniques used for human infection surveillance in these communities. However, both epidemiological data and theoretical results indicate that (i) transmission in the human population can persist at very low infection intensities even in the presence of routine control activities; (ii) the parasite can be reintroduced into parasite-free environments by very modest external inputs; and (iii) transmission at these low infection intensities exhibits very slow inter-year dynamics. These observations motivate the need for new, sensitive tools to identify low-level infections in mammalian or snail hosts, or the presence of S. japonicum in environmental media. Environmental monitoring offers an alternative, and perhaps more efficient, approach to large-scale surveillance of human infections in low transmission regions.

Inhibition of androgen receptor activity by histone deacetylase 4 through receptor SUMOylation.

The transcriptional activity of the androgen receptor (AR) is regulated by both ligand binding and post-translational modifications, including acetylation and small ubiquitin-like modifier (SUMO)ylation. Histone deacetylases (HDACs) are known to catalyze the removal of acetyl groups from both histones and non-histone proteins. In this study, we report that HDAC4 binds to and inhibits the activity of the AR. This inhibition was found to depend on the SUMOylation, instead of deacetylation, of the AR. Consistently, HDAC4 increases the level of AR SUMOylation in both whole-cell and cell-free assay systems, raising the possibility that the deacetylase may act as an E3 ligase for AR SUMOylation. Knock down of HDAC4 increases the activity of endogenous AR and androgen induction of prostate-specific antigen expression and prostate cancer cell growth, which is associated with decreased SUMOylation of the receptor. Overall, the studies identify HDAC4 as a positive regulator for AR SUMOylation, revealing a deacetylase-independent mechanism of HDAC action in prostate cancer cells.

[Study of the prognostic implications in patients with a transient ischaemic attack before the implementation of an agreed process of treatment in the health region of Lleida]. / Estudio de las implicaciones pronósticas del paciente con ataque isquémico transitorio antes de la implantación de un proceso consensuado de tratamiento en la región sanitaria de Lleida.

AIM: The transient ischemic attack (TIA) is a medical emergency because of their high risk of early recurrence. We study the evolution and management of patients with a TIA in our hospital before establishing a process management and treatment of this condition. PATIENTS AND METHODS: We included 180 consecutive patients with suspected TIA attended in the emergency department of our hospital between January 2006 and March 2007. We collected clinical variables (risk factors, age, clinical symptoms, duration, ABCD2). Cases were reviewed by two neurologists to establish the correlation with the diagnosis. We established the risk of cerebral infarction after one year follow-up. RESULTS: 31% of patients were discharged home. There were differences between the two groups regarding age (82.9 Y 7.5 vs 70.53 Y 10.7 years); ABCD2 scale score (1.5 Y 5.32 vs 4.44 Y 1.37); and atrial fibrillation (27.5% vs 8.6%). There was much greater delay and lack of complementary explorations. During follow-up, 23% of patients not hospitalized had recurrent stroke versus 6.7% of hospitalized patients. Despite the fact that only age more than 80 years was identified as predictor of stroke recurrence (hazard ratio = 8,72; 95% CI = 2.4-31.74; p = 0.001) in regression multivariate model, the Kaplan-Meier model showed a higher risk of stroke recurrence among not admitted patients (p = 0.012). CONCLUSION: In our area, the management of TIA patients in the emergency room had high impact on the evolution of these patients. A process management should be performed in order to achieve improvement in clinical praxis.

Histone deacetylases and the immunological network: implications in cancer and inflammation.

The initiation, magnitude and duration of an immune response against antigens are a tightly regulated process involving a dynamic, orchestrated balance of pro- and anti-inflammatory pathways in immune cells. Such a delicate balance is critical for allowing efficient immune response against foreign antigens while preventing autoimmune attack against self-antigens. In recent years, much effort has been devoted to understanding immune evasion by cancer cells. Also, significant advances have been made in mechanistically understanding the role of pro- and anti-inflammatory cytokines in the regulation of immune responses against antigens, including those expressed by tumors. However, we still know very little about the regulation of inflammatory/anti-inflammatory genes in their natural setting, the chromatin substrate. Several mechanisms have been identified to influence chromatin flexibility and allow dynamic changes in gene expression. Among those, chromatin modifications induced by acetylation and deacetylation of histone tails have gained wide attention. In this study, we discuss the role of histone deacetylases in the transcriptional regulation of genes involved in the inflammatory response and how these enzymes coordinate the dynamic expression of these genes during an immune response. This emerging knowledge is opening new avenues to better understand epigenetic regulation of inflammatory responses and providing new molecular targets for either amplifying or ameliorating immune responses.

Predictive value of ankle brachial index in patients with acute ischaemic stroke.

BACKGROUND: The ankle brachial index (ABI) is a known measure of lower-limb peripheral artery disease (PAD), as well as a marker for other cardiovascular disease events. OBJECTIVE: Our goal was to compare the prevalence of abnormal ABI scores (ABI or=3 (33.8% vs. 7.1%, P = 0.001) and large-artery atherosclerosis (LAA) (43.5% vs. 19.4%, P = 0.015). Multivariate analyses (logistic regression) only identified VRF > 3 as independently associated with low ABI (OR: 6.46; 1.81-23.02; P = 0.004). Abnormal ABI was associated with stroke recurrence (32.1% vs. 13.6%, P = 0.027) and the appearance of any major vascular event (50.0% vs. 17.0%, P < 0.001). In the logistic regression analysis, adjusted for VRF, age, and LAA, ABI remained as an independent predictor of vascular events (HR 3.99; 1.90-8.41 P < 0.001). CONCLUSION: Abnormal ABI was associated with classical risk factors, especially hypertension. The measurement of ABI amongst patients with IS appeared to be useful to identify high-risk patients and plan adequate prevention therapies.

[The extent of knowledge about strokes among the population of a rural area in the province of Lleida]. / Grado de conocimiento del ictus entre poblacion de area rural en la provincia de Lleida.

INTRODUCTION: Although stroke continues to be a significant cause of morbidity and mortality, the knowledge of warning signs and risk factors among general population is still insufficient. AIM: To assess the current knowledge of stroke (terminology, signs and symptoms, risk factors and attitude) among rural population of Baix Segria in Lleida in order to the best target and message, prior to educational campaigns. SUBJECTS AND METHODS: A structured interview using closeended questions was conducted among 153 users of Primary Health Centers. RESULTS: In our cohort, 6.5% ignored the disease, while 48 (31,4%) had good knowledge of risk factors (more than three risk factors) and 62 (40,5%) identified more than three warnings signs correctly. Only 31,1% would correctly act if stroke occurred. Transient ischemic attack was not considered as emergency. Most participants, 78,5%, would contact to primary care. Surprisingly, knowledge of stroke symptoms and risk factors was not associated with an increased chance of calling 061 or going to the hospital. Older respondents were less likely to recognize symptoms and to consider stroke as an emergency, while the university education was associated with good knowledge and actuation. CONCLUSION: The level of knowledge of established stroke risk factors, warning signs, and treatment in rural population of Lleida is low. Our data suggested not only that a community-based education program to increase public knowledge of stroke among rural population is necessary, but also we need to inform the people stroke is treatable.

HDAC3 represses the expression of NKG2D ligands ULBPs in epithelial tumour cells: potential implications for the immunosurveillance of cancer.

The expression of the NKG2D ligands on cancer cells leads to their recognition and elimination by host immune responses mediated by natural killer and T cells. UL16-binding proteins (ULBPs) are NKG2D ligands, which are scarcely expressed in epithelial tumours, favouring their evasion from the immune system. Herein, we investigated the epigenetic mechanisms underlying the repression of ULBPs in epithelial cancer cells. We show that ULBP1-3 expression is increased in tumour cells after exposure to the inhibitor of histone deacetylases (HDACs) trichostatin A (TSA), which enhances the natural killer cell-mediated cytotoxicity of HeLa cells. Our experiments showed that the transcription factor Sp3 is crucial in the activation of the ULBP1 promoter by TSA. Furthermore, by small interfering RNA-mediated knockdown and overexpression of HDAC1-3, we showed that HDAC3 is a repressor of ULBPs expression in epithelial cancer cells. Remarkably, TSA treatment caused the complete release of HDAC3 from the ULBP1-3 promoters. HDAC3 is recruited to the ULBP1 promoter through its interaction with Sp3 and TSA treatment interfered with this association. Together, we describe a new mechanism by which cancer cells may evade the immune response through the epigenetic modulation of the ULBPs expression and provide a model in which HDAC inhibitors may favour the elimination of transformed cells by increasing the immunogenicity of epithelial tumours.

HATs and HDACs: from structure, function and regulation to novel strategies for therapy and prevention.

Acetylation of the epsilon-amino group of a lysine residue was first discovered with histones in 1968, but the responsible enzymes, histone acetyltransferases and deacetylases, were not identified until the mid-1990s. In the past decade, knowledge about this modification has exploded, with targets rapidly expanding from histones to transcription factors and other nuclear proteins, and then to cytoskeleton, metabolic enzymes, and signaling regulators in the cytoplasm. Thus, protein lysine acetylation has emerged as a major post-translational modification to rival phosphorylation. In this issue of Oncogene, 19 articles review various aspects of the enzymes governing lysine acetylation, especially about their intimate links to cancer. To introduce the articles, we highlight here four central themes: (i) multisubunit enzymatic complexes; (ii) non-histone substrates in diverse cellular processes; (iii) interplay of lysine acetylation with other regulatory mechanisms, such as noncoding RNA-mediated gene silencing and activation; and (iv) novel therapeutic strategies and preventive measures to combat cancer and other human diseases.

Histone deacetylases and cancer.

Histone deacetylases (HDACs) regulate the expression and activity of numerous proteins involved in both cancer initiation and cancer progression. By removal of acetyl groups from histones, HDACs create a non-permissive chromatin conformation that prevents the transcription of genes that encode proteins involved in tumorigenesis. In addition to histones, HDACs bind to and deacetylate a variety of other protein targets including transcription factors and other abundant cellular proteins implicated in control of cell growth, differentiation and apoptosis. This review provides a comprehensive examination of the transcriptional and post-translational mechanisms by which HDACs alter the expression and function of cancer-associated proteins and examines the general impact of HDAC activity in cancer.

Differential regulation of human YY1 and caspase 7 promoters by prohibitin through E2F1 and p53 binding sites.

Prohibitin is a 30 kDa growth suppressive protein that has pleiotropic functions in the cell. Although prohibitin has been demonstrated to have potent transcriptional regulatory functions, it has also been proposed to facilitate protein folding in the mitochondria and promote cell migration in association with Raf-1. Our previous studies have shown that prohibitin physically interacts with the marked-box domain of E2F family members and represses their transcriptional activity; in contrast, prohibitin could bind to and enhance the transcriptional activity of p53. Here, we show that promoters of human YY1 (Yin and Yang 1) as well as caspase 7 genes are modulated by prohibitin. YY1 promoter activity was reduced upon overexpression of prohibitin, while it was enhanced when prohibitin was depleted by small interfering RNA techniques. The repressive effects of prohibitin on the YY1 promoter were mediated through E2F binding sites, as seen by mutational analysis and chromatin immunoprecipitation assays. Further, depletion of E2F1 prevented prohibitin from repressing the YY1 promoter. In contrast with YY1, prohibitin overexpression led to enhanced levels of caspase 7, whereas depletion of prohibitin reduced it. Interestingly, the caspase 7 promoter was found to have p53-binding sites and prohibitin activated this promoter through p53. These studies show that prohibitin can have diverse effects on the expression of different genes and the activity of various cellular promoters is affected by prohibitin. Further, it appears very likely that prohibitin carries out many of its cellular functions by affecting the transcription of different genes.

New insights into the transmission biology of urinary schistosomiasis in Zanzibar.

A better understanding of the transmission biology of urinary schistosomiasis in Zanzibar, Tanzania was only possible after the development of molecular DNA markers for identification of Bulinus africanus group snails, the potential intermediate hosts of Schistosoma haematobium. Hitherto, identification of natural populations of B. globosus and B. nasutus was problematic and the intermediate host status and distribution of either species remained speculative. By recourse to molecular markers, snail distribution maps could be drawn, revealing an allopatric distribution and, more importantly, leading to the discovery that B. nasutus played no role in transmission. Indeed, in Unguja the area of active transmission of S. haematobium to humans is confined within the distribution of B. globosus. This strong relationship may prove useful for predicting the distribution of urinary schistosomiasis within Zanzibar and, if snail schistosome compatibilities persist, in other areas nearby, e.g. coastal Tanzania and Kenya. The transmission biology of urinary schistosomiasis in Zanzibar is reviewed, the paper reports on ongoing malacological studies in Zanzibar and Kenya and finally closes by posing the question whether medical malacology forms an essential component associated with mass-scale chemotherapy control programmes.

Urinary schistosomiasis in schoolchildren on Zanzibar Island (Unguja), Tanzania: a parasitological survey supplemented with questionnaires.

The distribution of urinary schistosomiasis in schoolchildren on Zanzibar Island (Unguja) was surveyed in May 2001 to test a potential correlation with the distribution of snail species of the Bulinus africanus group and to record contemporary baseline epidemiological data. Quasi-random samples of 40 schoolchildren of mixed sexes were selected from each of 10 schools. Schistosoma haematobium infections were detected upon the basis of micro-haematuria with subsequent confirmation by microscopy examination for schistosome eggs. At the time of urine collection, each child was interviewed with a suite of 12 questions prepared as a standardized questionnaire. Total prevalence of urinary schistosomiasis (known locally as kichocho) was 12% although schistosome infections were absent in 5 schools. Schools located west of 39 degrees 19'E and north of 6 degrees 10'S harboured nearly all of the infections; the highest prevalence (55%) was found at Kinyasini where many B. globosus habitats occur nearby. The general level of understanding of kichocho was low (24%) and individual self-diagnosis was poor (sensitivity, 8.5%; specificity, 85%). Grouped freshwater-contact patterns of schoolchildren differed significantly between schools and correlated well with prevalence of infections within schools. Across the island the area of active transmission of S. haematobium to humans appears confined within the distribution of B. globosus. There was no epidemiological evidence to suggest any involvement of B. nasutus in local transmission, confirming previous laboratory findings. In areas where B. globosus occurs, targeted snail control should be considered, to reduce schistosome transmission.

Yin-Yang 1 activates interleukin-4 gene expression in T cells.

Interleukin-4 (IL-4) is a multifunctional cytokine that plays an important role in immune and inflammatory responses. Expression of the IL-4 gene is tightly controlled at the level of gene transcription by both positive and negative regulatory elements in the IL-4 promoter. Several constitutive nuclear factors have been identified that can interact with IL-4 promoter elements in DNA binding assays. Here we report that the zinc-finger protein YY-1 (Yin-Yang 1) can bind to multiple elements within the human IL-4 promoter. Cotransfection of Jurkat T cells with different IL-4 promoter/reporter constructs together with expression vectors encoding antisense, wild-type, or zinc finger-deleted mutant YY-1 suggested that YY-1 enhanced IL-4 promoter activity in a DNA-binding domain-dependent manner. Site-directed mutagenesis revealed that a proximal YY-1-binding site, termed Y0 ((-59)TCATTTT(-53)), was essential for YY-1-driven IL-4 promoter activity. In addition, cotransfected YY-1 enhanced both IL-4 promoter activity and endogenous IL-4 gene expression in nontransformed peripheral blood T cells. Thus, YY-1 positively regulates IL-4 gene expression in lymphocytes.