RNA Interference by Single- and Double-stranded siRNA With a DNA Extension Containing a 3′ Nuclease-resistant Mini-hairpin Structure

Selective gene silencing by RNA interference (RNAi) involves double-stranded small interfering RNA (ds siRNA) composed of single-stranded (ss) guide and passenger RNAs. siRNA is recognized and processed by Ago2 and C3PO, endonucleases of the RNA-induced silencing complex (RISC). RISC cleaves passenger RNA, exposing the guide RNA for base-pairing with its homologous mRNA target. Remarkably, the 3' end of passenger RNA can accommodate a DNA extension of 19-nucleotides without loss of RNAi function. This construct is termed passenger-3'-DNA/ds siRNA and includes a 3'-nuclease-resistant mini-hairpin structure. To test this novel modification further, we have now compared the following constructs: (I) guide-3'-DNA/ds siRNA, (II) passenger-3'-DNA/ds siRNA, (III) guide-3'-DNA/ss siRNA, and (IV) passenger-3'-DNA/ss siRNA. The RNAi target was SIRT1, a cancer-specific survival factor. Constructs I-III each induced selective knock-down of SIRT1 mRNA and protein in both noncancer and cancer cells, accompanied by apoptotic cell death in the cancer cells. Construct IV, which lacks the SIRT1 guide strand, had no effect. Importantly, the 3'-DNA mini-hairpin conferred nuclease resistance to constructs I and II. Resistance required the double-stranded RNA structure since single-stranded guide-3'-DNA/ss siRNA (construct III) was susceptible to serum nucleases with associated loss of RNAi activity. The potential applications of 3'-DNA/siRNA constructs are discussed. Molecular Therapy-Nucleic Acids (2014) 2, e141; doi:10.1038/mtna.2013.68; published online 7 January 2014

Identification of LDH-A as a therapeutic target for cancer cell killing via (i) p53/NAD(H)-dependent and (ii) p53 independent pathways

Most cancer cells use aerobic glycolysis to fuel their growth. The enzyme lactate dehydrogenase-A (LDH-A) is key to cancer’s glycolytic phenotype, catalysing the regeneration of nicotinamide adenine dinucleotide (NAD þ ) from reduced nicotinamide adenine dinucleotide (NADH) necessary to sustain glycolysis. As such, LDH-A is a promising target for anticancer therapy. Here we ask if the tumour suppressor p53, a major regulator of cellular metabolism, influences the response of cancer cells to LDH-A suppression. LDH-A knockdown by RNA interference (RNAi) induced cancer cell death in p53 wild-type, mutant and p53-null human cancer cell lines, indicating that endogenous LDH-A promotes cancer cell survival irrespective of cancer cell p53 status. Unexpectedly,however,weuncoveredanovelroleforp53intheregulationofcancercellNADþ anditsreducedformNADH.Thus, LDH-A silencing by RNAi, or its inhibition using a small-molecule inhibitor, resulted in a p53-dependent increase in the cancer cell ratioofNADH:NADþ.Thiseffectwasspecificforp53þ/þ cancercellsandcorrelatedwith(i)reducedactivityofNADþ-dependent deacetylase sirtuin 1 (SIRT1) and (ii) an increase in acetylated p53, a known target of SIRT1 deacetylation activity. In addition, activation of the redox-sensitive anticancer drug EO9 was enhanced selectively in p53 þ / þ cancer cells, attributable to increased activity of NAD(P)H-dependent oxidoreductase NQO1 (NAD(P)H quinone oxidoreductase 1). Suppressing LDH-A increased EO9-inducedDNAdamageinp53þ/þ cancercells,butimportantlyhadnoadditiveeffectinnon-cancercells.Ourresultsidentifya unique strategy by which the NADH/NADþ cellular redox status can be modulated in a cancer-specific, p53-dependent manner and we show that this can impact upon the activity of important NAD(H)-dependent enzymes. To summarise, this work indicates two distinct mechanisms by which suppressing LDH-A could potentially be used to kill cancer cells selectively, (i) through induction of apoptosis, irrespective of cancer cell p53 status and (ii) as a part of a combinatorial approach with redox-sensitive anticancer drugs via a novel p53/NAD(H)-dependent mechanism

Social-environmental factors and suicide mortality: A narrative review of over 200 articles

Suicide mortality in a population has long been thought to be sensitive to social, economic and cultural contexts. This review examined research on the relationship between social-environmental variables and suicide mortality published over a ten-year period. The main areas covered in the review included: the economy and income, unemployment, relationship status, fertility and birth rates, female participation in the workforce, religion, migration, location of residence, modernisation, media reporting, alcohol, and access to suicide methods. Results of the review indicated that rates of suicide mortality (deaths per 100,000 in a population) were sensitive to a wide range of social factors. There were relatively stable as- sociations noted between divorce and unemployment with suicide mortality, while many of the reported associations between suicide mortality and other social variables (such as religion, fertility and female participation in the workforce) were influenced by contextual factors and time. These findings indicate the importance of considering the relationship between social factors and suicide as dynamic phenomena.Griffith Health, Australian Institute for Suicide Research & PreventionFull Tex

Sickness absence and psychosocial job quality: an analysis from a longitudinal survey of working Australians, 2005-2012

Sickness absence is associated with adverse health, organizational, and societal outcomes. Using data from a longitudinal cohort study of working Australians (the Household, Income and Labour Dynamics in Australia (HILDA) Survey), we examined the relationship between changes in individuals' overall psychosocial job quality and variation in sickness absence. The outcome variables were paid sickness absence (yes/no) and number of days of paid sickness absence in the past year (2005-2012). The main exposure variable was psychosocial job quality, measured using a psychosocial job quality index (levels of job control, demands and complexity, insecurity, and perceptions of unfair pay). Analysis was conducted using longitudinal fixed-effects logistic regression models and negative binomial regression models. There was a dose-response relationship between the number of psychosocial job stressors reported by an individual and the odds of paid sickness absence (1 adversity: odds ratio (OR) = 1.26, 95% confidence interval (CI): 1.09, 1.45 (P = 0.002); 2 adversities: OR = 1.28, 95% CI: 1.09, 1.51 (P = 0.002); â‰13 adversities: OR = 1.58, 95% CI: 1.29, 1.94 (P < 0.001)). The negative binomial regression models also indicated that respondents reported a greater number of days of sickness absence in response to worsening psychosocial job quality. These results suggest that workplace interventions aiming to improve the quality of work could help reduce sickness absence

Halcyornis toliapicus (aves: Lower Eocene, England) indicates advanced neuromorphology in Mesozoic Neornithes

Our recent X-ray micro computer-tomographic (μCT) investigations of Prophaethon shrubsolei and Odontopteryx toliapica from the Lower Eocene London Clay Formation of England revealed the avian brain to have been essentially modern in form by 55 Ma, but that an important vision-related synapomorphy of living birds, the eminentia sagittalis of the telencephalon, was poorly developed. This evidence suggested that the feature probably appeared close to the end of the Mesozoic. Here we use μCT analysis to describe the endocranium of Halcyornis toliapicus, also from the London Clay Formation. The affinities of Halcyornis have been hotly debated, with the taxon referred to the Charadriiformes (Laridae), Coraciiformes (Alcedinidae, and its own family Halcyornithidae) and most recently that Halcyornithidae may be a possible senior synonym of Pseudasturidae (Pan-Psittaciformes). Unlike Prophaethon and Odontopteryx, the eminentia sagittalis of Halcyornis is strongly developed and comparable to that of living species. Like those London Clay taxa, the eminentia sagittalis occupies a rostral position on the telencephalon. The senses of Halcyornis appear to have been well developed. The length of the cochlear duct of the inner ear indicates a hearing sensitivity within the upper range of living species, and enlarged olfactory lobes suggest a reasonable reliance on sense of smell. The optic nerves were especially well developed which, together with the strong development of the eminentia sagittalis, indicates a high degree of visual specialization in Halcyornis. The advanced development of the eminentia sagittalis further supports a Mesozoic age for the appearance of this structure and associated neural architectural complexity found in extant Aves. The eminentia sagittalis of living Psittaciformes is situated caudally on the telencephalon, making a Pan-Psittaciformes relationship unlikely for Halcyorni

Workplace mental health: developing an integrated intervention approach

BACKGROUND: Mental health problems are prevalent and costly in working populations. Workplace interventions to address common mental health problems have evolved relatively independently along three main threads or disciplinary traditions: medicine, public health, and psychology. In this Debate piece, we argue that these three threads need to be integrated to optimise the prevention of mental health problems in working populations. DISCUSSION: To realise the greatest population mental health benefits, workplace mental health intervention needs to comprehensively 1) protect mental health by reducing work-related risk factors for mental health problems; 2) promote mental health by developing the positive aspects of work as well as worker strengths and positive capacities; and 3) address mental health problems among working people regardless of cause. We outline the evidence supporting such an integrated intervention approach and consider the research agenda and policy developments needed to move towards this goal, and propose the notion of integrated workplace mental health literacy. SUMMARY: An integrated approach to workplace mental health combines the strengths of medicine, public health, and psychology, and has the potential to optimise both the prevention and management of mental health problems in the workplace

Mental Disorders and Communication of Intent to Die in Indigenous Suicide Cases, Queensland, Australia

In comparing Indigenous to non-Indigenous suicide in Australia, this study focussed on the frequency of the association between some psychiatric conditions, such as depression and alcohol abuse, and some aspect of suicidality, in particular communication of suicide intent. Logistic regression was implemented to analyze cases of Indigenous (n = 471) versus non-Indigenous suicides (n = 6,655), using the Queensland Suicide Register as a data source. Compared to non-Indigenous suicides, Indigenous cases had lower odds of being diagnosed with unipolar depression, seeking treatment for psychiatric conditions or leaving a suicide note. Indigenous suicides had greater odds of verbally communicating suicide intent and having a history of alcohol and substance use. The magnitude of these differences is remarkable, underscoring the need for culturally sensitive suicide prevention efforts

Oncogenic viral protein HPV E7 up-regulates the SIRT1 longevity protein in human cervical cancer cells

Senescence is blocked in human cervical keratinocytes infected with high risk human papillomavirus (e.g. HPV type16). Viral oncoproteins HPV E6 and HPV E7 access the cell cycle via cellular p53 and retinoblastoma proteins respectively. Previously we have shown that HPV E7, not HPV E6, is also responsible for cervical cancer cell survival (SiHa cells; HPV type16). We now present evidence that SIRT1, an aging-related NAD-dependent deacetylase, mediates HPV E7 survival function in SiHa cervical cancer cells. Moreover, HPV E7 up-regulates SIRT1 protein when expressed in primary human keratinocytes. Conversely, SIRT1 levels decrease following RNAi-mediated silencing of HPV E7 in SiHa cells. Silencing HPV E6 has no effect on SIRT1 but, as expected, causes marked accumulation of p53 protein accompanied by p53-mediated up-regulation of p21. However, p53 acetylation (K382Ac) was barely detectable. Since p53 is a known SIRT1 substrate we propose that elevated SIRT1 levels (induced by HPV E7) attenuate p53 pro-apoptotic capacity via its de-acetylation. Our discovery that HPV E7 up-regulates SIRT1 links a clinically important oncogenic virus with the multi-functional SIRT1 protein. This link may open the way for a more in-depth understanding of the process of HPV-induced malignant transformation and also of the inter-relationships between aging and cancer