Growth differentiation factor 15 (GDF15), a distant member of the transforming growth factor (TGF)-β family, is a secreted protein that circulates as a 25-kDa dimer. In humans, elevated GDF15 ...correlates with weight loss, and the administration of GDF15 to mice with obesity reduces body weight, at least in part, by decreasing food intake. The mechanisms through which GDF15 reduces body weight remain poorly understood, because the cognate receptor for GDF15 is unknown. Here we show that recombinant GDF15 induces weight loss in mice fed a high-fat diet and in nonhuman primates with spontaneous obesity. Furthermore, we find that GDF15 binds with high affinity to GDNF family receptor α-like (GFRAL), a distant relative of receptors for a distinct class of the TGF-β superfamily ligands. Gfral is expressed in neurons of the area postrema and nucleus of the solitary tract in mice and humans, and genetic deletion of the receptor abrogates the ability of GDF15 to decrease food intake and body weight in mice. In addition, diet-induced obesity and insulin resistance are exacerbated in GFRAL-deficient mice, suggesting a homeostatic role for this receptor in metabolism. Finally, we demonstrate that GDF15-induced cell signaling requires the interaction of GFRAL with the coreceptor RET. Our data identify GFRAL as a new regulator of body weight and as the bona fide receptor mediating the metabolic effects of GDF15, enabling a more comprehensive assessment of GDF15 as a potential pharmacotherapy for the treatment of obesity.
The inhibition of KSP causes mitotic arrest by activating the spindle assembly checkpoint. While transient inhibition of KSP leads to reversible mitotic arrest, prolonged exposure to a KSP inhibitor ...induces apoptosis. Induction of apoptosis by the KSP inhibitor couples with mitotic slippage. Slippage-refractory cells show resistance to KSP inhibitor-mediated lethality, whereas promotion of slippage after mitotic arrest enhances apoptosis. However, attenuation of the spindle checkpoint confers resistance to KSP inhibitor-induced apoptosis. Furthermore, sustained KSP inhibition activates the proapoptotic protein, Bax, and both activation of the spindle checkpoint and subsequent mitotic slippage are required for Bax activation. These studies indicate that in response to KSP inhibition, activation of the spindle checkpoint followed by mitotic slippage initiates apoptosis by activating Bax.
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Single-stranded silencing RNAs (ss siRNA), while not as potent as duplex RNAs, have the potential to become a novel platform technology in RNA interference based gene silencing by ...virtue of their simplicity and plausibly favorable characteristics in pharmacokinetics and biodistribution. Like other therapeutic pharmaceutical agents, ss siRNA can be optimized to achieve higher potency through a structure–activity based approach. Systematic chemical modification at each position of a 21-mer oligonucleotide identified 2′,5′-linked 3′-deoxythymidine (3dT) at position 1 and locked nucleic acids (LNAs) at the seed region as key components to afford significant enhancement in knockdown activity both in vitro and in vivo. Further optimization by additional chemical modifications should enable ss siRNA as an alternative gene silencing modality.
Mouse models with liver-specific expression of firefly luciferase were developed that enable a noninvasive and longitudinal assessment of small-interfering RNA (siRNA)–mediated gene silencing in ...hepatocytes of live animals via bioluminescence imaging. Using these models, a set of lipid nanoparticles (LNPs) with different compositions of cationic lipids, polyethylene glycol (PEG), and cholesterol, were tested for their abilities in delivering a luciferase siRNA to the liver via systemic administration. A dose-dependent luciferase knockdown by LNP/siRNA assemblies was measured by in vivo bioluminescence imaging, which correlated well with the results from parallel ex vivo analyses of luciferase mRNA and protein levels in the liver. RNA interference (RNAi)–mediated target silencing was further confirmed by the detection of RNAi-specific target mRNA cleavage. A single dose of LNP02L at 3 mg/kg (siRNA) caused 90% reduction of luciferase expression and the target repression lasted for at least 10 days. With identical components, LNPs containing 2% PEG are more potent than those with 5.4% PEG. Our results demonstrate that these liver-luciferase mouse models provide a powerful tool for a high-throughput evaluation of hepatic delivery platforms by noninvasive imaging and that the molar ratio of PEG lipid can affect the efficacy of LNPs in silencing liver targets via systemic administration.
2,4-Diaryl-2,5-dihydropyrroles are reported as potent inhibitors of the mitotic kinesin KSP.
The evolution of 2,4-diaryl-2,5-dihydropyrroles as inhibitors of KSP is described. Introduction of basic ...amide and urea moieties to the dihydropyrrole nucleus enhanced potency and aqueous solubility, simultaneously, and provided compounds that caused mitotic arrest of A2780 human ovarian carcinoma cells with EC
50s
<
10
nM. Ancillary hERG activity was evaluated for this series of inhibitors.
Aim
To evaluate trends in admission temperature and its effect on mortality and short‐term morbidities in extremely preterm infants.
Methods
A regional cohort study of infants born at 23–28 weeks’ ...gestation and admitted to the 10 neonatal intensive care units in New South Wales and the Australian Capital Territory between 1994 and 2012. Hypothermia was defined as skin temperature <36°C on admission to the neonatal intensive care unit. The primary outcome was hospital mortality.
Results
In total, 6267 infants were included. Mean admission temperatures improved significantly from 35.6°C in 1994 to 36.4°C in 2012 (R < 0.88). The incidence of hypothermia was 29.5 and 13.9% between 1994–2005 and 2006–2012, respectively. In comparison with normothermic infants, hypothermic infants had lower gestational age at birth (26 vs. 27 weeks) and lower birthweight (800 vs. 976 g). In‐hospital mortality was higher in hypothermic infants (28.5 vs. 12.9%; odds ratio (OR) 2.69, 95% confidence interval (CI) 2.37–3.06). Severe intraventricular haemorrhage (12.1 vs. 8.5%, OR 1.48, 95% CI 1.25–1.75), necrotising enterocolitis (NEC) (11.0 vs. 7.5%; OR 1.54, 95% CI 1.29–1.83) and severe retinopathy of prematurity (16.5 vs. 8.9%; OR 2.02, 95% CI 1.70–2.39) were significantly higher in hypothermic infants. Multivariate regression analysis showed hypothermia was an independent risk factor for increased mortality (AOR (adjusted odds ratio ) 1.50, 95% CI 1.29–1.74, P < 0.001) and NEC (AOR 1.28, 95% CI 1.05–1.55, P = 0.01).
Conclusions
Admission temperatures improved during the time period. Hypothermia at admission was associated with a significant increase in mortality and NEC.
The proto-oncogene c-myc is the cellular homologue of the transforming sequence carried by the avian myelocytomastosis virus MC29. A growing body of evidence implicates structural and functional ...alterations in and around proto-oncogenes such as c-myc in tumorogenesis. Here we report that comparison of the structure of myc from a ductal adenocarcinoma of the breast and from normal breast tissue of the same patient (Sc) revealed a tumour-specific rearrangement of one myc locus and amplification of the other myc locus. (For myc reviews see refs 1-4; for myc involvement in breast neoplasia see refs 5-7.) Within the second intron of the rearranged locus was a non-myc sequence with nearly complete homology to a long interspersed repetitive element (a LINE-1 sequence or L1). In this case, the L1 sequence has functioned as a mobile genetic element to produce a somatic mutation.
Health systems administrators and clinicians need refined calculations of the attributable cost of infections due to drug-resistant microorganisms to develop and assess cost-effective prevention ...strategies that deal with these infections. To date, however, efforts to provide this information have yielded widely variable and often conflicting estimates. This lack of reproducibility is largely attributable to problems in study design and in the methods used to identify and measure costs. Addressing these methodological issues was the focus of a workshop that included participants from a broad range of backgrounds, including economics, epidemiology, health care management, health care outcomes research, and clinical care. This workshop summary presents the advantages and disadvantages of various research designs as well as particular methodological issues related to the measurement of the economic cost of resistance in health care settings. Suggestions are made for needed common definitions and approaches, study areas for future research are considered, and priority investigations are identified.
Cutaneous squamous cell carcinoma (cSCC) has a high tumour mutational burden (50 mutations per megabase DNA pair). Here, we combine whole-exome analyses from 40 primary cSCC tumours, comprising 20 ...well-differentiated and 20 moderately/poorly differentiated tumours, with accompanying clinical data from a longitudinal study of immunosuppressed and immunocompetent patients and integrate this analysis with independent gene expression studies. We identify commonly mutated genes, copy number changes and altered pathways and processes. Comparisons with tumour differentiation status suggest events which may drive disease progression. Mutational signature analysis reveals the presence of a novel signature (signature 32), whose incidence correlates with chronic exposure to the immunosuppressive drug azathioprine. Characterisation of a panel of 15 cSCC tumour-derived cell lines reveals that they accurately reflect the mutational signatures and genomic alterations of primary tumours and provide a valuable resource for the validation of tumour drivers and therapeutic targets.
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