MiR-142-3p is downregulated in aggressive p53 mutant mouse models of pancreatic ductal adenocarcinoma by hypermethylation of its locus

Pancreatic ductal adenocarcinoma (PDAC) is an extremely aggressive disease with poor prognostic implications. This is partly due to a large proportion of PDACs carrying mutations in TP53, which impart gain-of-function characteristics that promote metastasis. There is evidence that microRNAs (miRNAs) may play a role in both gain-of-function TP53 mutations and metastasis, but this has not been fully explored in PDAC. Here we set out to identify miRNAs which are specifically dysregulated in metastatic PDAC. To achieve this, we utilised established mouse models of PDAC to profile miRNA expression in primary tumours expressing the metastasis-inducing mutant p53R172H and compared these to two control models carrying mutations, which promote tumour progression but do not induce metastasis. We show that a subset of miRNAs are dysregulated in mouse PDAC tumour tissues expressing mutant p53R172H, primary cell lines derived from mice with the same mutations and in TP53 null cells with ectopic expression of the orthologous human mutation, p53R175H. Specifically, miR-142-3p is downregulated in all of these experimental models. We found that DNA methyltransferase 1 (Dnmt1) is upregulated in tumour tissue and cell lines, which express p53R172H. Inhibition or depletion of Dnmt1 restores miR-142-3p expression. Overexpression of miR-142-3p attenuates the invasive capacity of p53R172H-expressing tumour cells. MiR-142-3p dysregulation is known to be associated with cancer progression, metastasis and the miRNA is downregulated in patients with PDAC. Here we link TP53 gain-of-function mutations to Dnmt1 expression and in turn miR-142-3p expression. Additionally, we show a correlation between expression of these genes and patient survival, suggesting that they may have potential to be therapeutic targets

‘Our voice started off as a whisper and now it is a great big roar’ : The Salford Dementia Associate Panel as a model of involvement in research activities

This paper presents the work of the ‘Salford Dementia Associate Panel’, based at the Salford Institute for Dementia, Salford University (UK). We discuss the roles of the Dementia Associates, in particular around the areas of engagement and research. The panel is made up of people living with dementia, and current and former care partners. It highlights the development of this group over a four-year period and demonstrates over time how the role of a Dementia Associate member has evolved. The panel is involved in research, education and public engagement activities conducted by staff and students within the Institute. The motivations for becoming involved are clearly articulated and demonstrate how the personal backgrounds of individuals have driven the collective involvement and desire to bring about change. The benefits and challenges associated with working as part of a panel are discussed. We conclude by bringing together our experiences as a set of suggestions for others who may wish to create a similar forum to promote the involvement of people living with dementia and former and current care partners

Proteinase-activated receptor 2 is involved in the behavioural changes associated with sickness behaviour

Proteinase-activated receptor-2 (PAR2) is widely expressed in the CNS but whether it plays a key role in inflammation-related behavioural changes remains unknown. Hence, in the present study we have examined whether PAR2 contributes to behaviour associated with systemic inflammation using PAR2 transgenic mice. The onset of sickness behaviour was delayed and the recovery accelerated in PAR2-/- mice in the LPS-induced model of sickness behaviour. In contrast, PAR2 does not contribute to behaviour under normal conditions. In conclusion, these data suggest that PAR2 does not contribute to behaviour in the normal healthy brain but it plays a role in inflammation-related behavioural changes

Managing for rainfall variability: effect of grazing strategy on cattle production in a dry tropical savanna

Rainfall variability is a challenge to sustainable and pro. table cattle production in northern Australia. Strategies recommended to manage for rainfall variability, like light or variable stocking, are not widely adopted. This is due partly to the perception that sustainability and profitability are incompatible. A large, long-term grazing trial was initiated in 1997 in north Queensland, Australia, to test the effect of different grazing strategies on cattle production. These strategies are: (i) constant light stocking (LSR) at long-term carrying capacity (LTCC); (ii) constant heavy stocking (HSR) at twice LTCC; (iii) rotational wet-season spelling (R/Spell) at 1.5 LTCC; (iv) variable stocking (VAR), with stocking rates adjusted in May based on available pasture; and (v) a Southern Oscillation Index (SOI) variable strategy, with stocking rates adjusted in November, based on available pasture and SOI seasonal forecasts. Animal performance varied markedly over the 10 years for which data is presented, due to pronounced differences in rainfall and pasture availability. Nonetheless, lighter stocking at or about LTCC consistently gave the best individual liveweight gain (LWG), condition score and skeletal growth; mean LWG per annum was thus highest in the LSR (113 kg), intermediate in the R/Spell (104 kg) and lowest in the HSR(86 kg). MeanLWGwas 106 kg in the VAR and 103 kg in the SOI but, in all years, the relative performance of these strategies was dependent upon the stocking rate applied. After 2 years on the trial, steers from lightly stocked strategies were 60-100 kg heavier and received appreciable carcass price premiums at the meatworks compared to those under heavy stocking. In contrast, LWG per unit area was greatest at stocking rates of about twice LTCC; mean LWG/ha was thus greatest in the HSR (21 kg/ha), but this strategy required drought feeding in four of the 10 years and was unsustainable. Although LWG/ha was lower in the LSR (mean 14 kg/ha), or in strategies that reduced stocking rates in dry years like the VAR(mean 18 kg/ha) and SOI (mean 17 kg/ha), these strategies did not require drought feeding and appeared sustainable. The R/Spell strategy (mean 16 kg/ha) was compromised by an ill-timed fire, but also performed satisfactorily. The present results provide important evidence challenging the assumption that sustainable management in a variable environment is unprofitable. Further research is required to fully quantify the long-term effects of these strategies on land condition and profitability and to extrapolate the results to breeder performance at the property level

The C-terminal domain of zDHHC2 contains distinct sorting signals that regulate intracellular localisation in neurons and neuroendocrine cells

The S-acyltransferase zDHHC2 mediates dynamic S-acylation of PSD95 and AKAP79/150, which impacts synaptic targeting of AMPA receptors. zDHHC2 is responsive to synaptic activity and catalyses the increased S-acylation of PSD95 that occurs following action potential blockade or application of ionotropic glutamate receptor antagonists. These treatments have been proposed to increase plasma membrane delivery of zDHHC2 via an endosomal cycling pathway, enhancing substrate accessibility. To generate an improved understanding of zDHHC2 trafficking and how this might be regulated by neuronal activity, we searched for intramolecular signals that regulate enzyme localisation. Two signals were mapped to the C-terminal tail of zDHHC2: a non-canonical dileucine motif [SxxxLL] and a downstream NP motif. Mutation of these signals enhanced plasma membrane accumulation of zDHHC2 in both neuroendocrine PC12 cells and rat hippocampal neurons, consistent with reduced endocytic retrieval. Furthermore, mutation of these signals also increased accumulation of the enzyme in neurites. Interestingly, several threonine and serine residues are adjacent to these sorting motifs and analysis of phospho-mimetic mutants highlighted a potential role for phosphorylation in regulating the efficacy of these signals. This study offers new molecular insight into the signals that determine zDHHC2 localisation and highlights a potential mechanism to regulate these trafficking signals

Increased expression of IL-16 in the brain of experimental autoimmune encephalomyelitis

Multiple Sclerosis (MS) is a demyelinating disease of the CNS, whose pathophysiology involves both inflammatory and neurodegenerative components. CD4+ T cells are one of the key mediators of disease initiation and progression; however CD4 i s also the receptor for the pro-inflammatory cytokine, interleukin - 16 (IL - 16). IL - 16 has been proposed to play a role in several autoimmune diseases, but the exact role of IL - 16 in the CNS during MS initiation and progression remains unclear. Therefore, the aim of this study was to examine the expression and distribution of IL - 16 in CNS tissue and investigate whether expression levels correlate with neuro-inflammation in experimental autoimmune encephalomyelitis (EAE), a murine model of MS. EAE was induced in 6 week old C 57BL/6J female mice by immunisation with MOG35 - 55 peptide and adjuvants. Tissue was harvested at onset (day 11), peak (day 16) and resolution (day 26), and immunofluorescence staining carried out to determine CD45, CD4 and IL - 16 expression and localisation in the brain of both control and EAE mice. In addition, co-localisation of IL - 16 with CNS and immune cell subtypes was performed using a Mesolens microscope (McConnell et al., 2016), which allows subcellular detail to be obtained from wide - field epifluorescence images. Expression of IL - 16 and CD4 was observed primarily within the lesions of cerebellum and hippocampus of the EAE brain, whereas little expression was observed in control brains. IL - 16 expression was highest at onset with 76 ±2.8% of cells ( n=3) within these lesions expressing IL - 16. This was reduced to 48±2.4% (n=3) at peak and 16 ±1.3% at resolution (n=3). Co-localization studies revealed that IL - 16 was expressed primarily by infiltrating immune cells but not by neurons or astrocytes. Co-localization of IL - 16 with immune cells in brain lesions of EAE mice suggests that infiltrating immune cells are the primary source of IL - 16. Further investigation is required if IL - 16 is pro-inflammatory or anti-inflammatory in the CNS during EAE

A 340/380 nm light emitting diode illuminator for Fura-2 AM ratiometric Ca2+ imaging of live cells with better than 5 nM precision

We report the first demonstration of a fast wavelength-switchable 340/380 nm light emitting diode (LED) illuminator for Fura-2 ratiometric Ca2+ imaging of live cells. The LEDs closely match the excitation peaks of bound and free Fura-2 and enables the precise detection of cytosolic Ca2+ concentrations, which is only limited by the Ca2+ response of Fura-2. Using this illuminator, we have shown that Fura-2 acetoxymethyl ester (AM) concentrations as low as 250 nM can be used to detect induced Ca2+ events in tsA-201 cells and while utilizing the 150 µs switching speeds available, it was possible to image spontaneous Ca2+ transients in hippocampal neurons at a rate of 24.39 Hz that were blunted or absent at typical 0.5 Hz acquisition rates. Overall, the sensitivity and acquisition speeds available using this LED illuminator significantly improves the temporal resolution that can be obtained in comparison to current systems and supports optical imaging of fast Ca2+ events using Fura-2