MCL-1 is essential for survival but dispensable for metabolic fitness of FOXP3+ regulatory T cells

FOXP3+ regulatory T (Treg) cells are essential for maintaining immunological tolerance. Given their importance in immune-related diseases, cancer and obesity, there is increasing interest in targeting the Treg cell compartment therapeutically. New pharmacological inhibitors that specifically target the prosurvival protein MCL-1 may provide this opportunity, as Treg cells are particularly reliant upon this protein. However, there are two distinct isoforms of MCL-1; one located at the outer mitochondrial membrane (OMM) that is required to antagonize apoptosis, and another at the inner mitochondrial membrane (IMM) that is reported to maintain IMM structure and metabolism via ATP production during oxidative phosphorylation. We set out to elucidate the relative importance of these distinct biological functions of MCL-1 in Treg cells to assess whether MCL-1 inhibition might impact upon the metabolism of cells able to resist apoptosis. Conditional deletion of Mcl1 in FOXP3+ Treg cells resulted in a lethal multiorgan autoimmunity due to the depletion of the Treg cell compartment. This striking phenotype was completely rescued by concomitant deletion of the apoptotic effector proteins BAK and BAX, indicating that apoptosis plays a pivotal role in the homeostasis of Treg cells. Notably, MCL-1-deficient Treg cells rescued from apoptosis displayed normal metabolic capacity. Moreover, pharmacological inhibition of MCL-1 in Treg cells resistant to apoptosis did not perturb their metabolic function. We conclude that Treg cells require MCL-1 only to antagonize apoptosis and not for metabolism. Therefore, MCL-1 inhibition could be used to manipulate Treg cell survival for clinical benefit without affecting the metabolic fitness of cells resisting apoptosis

The study of atmospheric ice-nucleating particles via microfluidically generated droplets

Ice-nucleating particles (INPs) play a significant role in the climate and hydrological cycle by triggering ice formation in supercooled clouds, thereby causing precipitation and affecting cloud lifetimes and their radiative properties. However, despite their importance, INP often comprise only 1 in 10³–10⁶ ambient particles, making it difficult to ascertain and predict their type, source, and concentration. The typical techniques for quantifying INP concentrations tend to be highly labour-intensive, suffer from poor time resolution, or are limited in sensitivity to low concentrations. Here, we present the application of microfluidic devices to the study of atmospheric INPs via the simple and rapid production of monodisperse droplets and their subsequent freezing on a cold stage. This device offers the potential for the testing of INP concentrations in aqueous samples with high sensitivity and high counting statistics. Various INPs were tested for validation of the platform, including mineral dust and biological species, with results compared to literature values. We also describe a methodology for sampling atmospheric aerosol in a manner that minimises sampling biases and which is compatible with the microfluidic device. We present results for INP concentrations in air sampled during two field campaigns: (1) from a rural location in the UK and (2) during the UK’s annual Bonfire Night festival. These initial results will provide a route for deployment of the microfluidic platform for the study and quantification of INPs in upcoming field campaigns around the globe, while providing a benchmark for future lab-on-a-chip-based INP studies

Acetylated histone variant H2A.Z is involved in the activation of neo-enhancers in prostate cancer.

Acetylation of the histone variant H2A.Z (H2A.Zac) occurs at active promoters and is associated with oncogene activation in prostate cancer, but its role in enhancer function is still poorly understood. Here we show that H2A.Zac containing nucleosomes are commonly redistributed to neo-enhancers in cancer resulting in a concomitant gain of chromatin accessibility and ectopic gene expression. Notably incorporation of acetylated H2A.Z nucleosomes is a pre-requisite for activation of Androgen receptor (AR) associated enhancers. H2A.Zac nucleosome occupancy is rapidly remodeled to flank the AR sites to initiate the formation of nucleosome-free regions and the production of AR-enhancer RNAs upon androgen treatment. Remarkably higher levels of global H2A.Zac correlate with poorer prognosis. Altogether these data demonstrate the novel contribution of H2A.Zac in activation of newly formed enhancers in prostate cancer

FOXM1 Induces a Global Methylation Signature That Mimics the Cancer Epigenome in Head and Neck Squamous Cell Carcinoma

The oncogene FOXM1 has been implicated in all major types of human cancer. We recently showed that aberrant FOXM1 expression causes stem cell compartment expansion resulting in the initiation of hyperplasia. We have previously shown that FOXM1 regulates HELLS, a SNF2/helicase involved in DNA methylation, implicating FOXM1 in epigenetic regulation. Here, we have demonstrated using primary normal human oral keratinocytes (NOK) that upregulation of FOXM1 suppressed the tumour suppressor gene p16INK4A (CDKN2A) through promoter hypermethylation. Knockdown of HELLS using siRNA re-activated the mRNA expression of p16INK4A and concomitant downregulation of two DNA methyltransferases DNMT1 and DNMT3B. The dose-dependent upregulation of endogenous FOXM1 (isoform B) expression during tumour progression across a panel of normal primary NOK strains (n = 8), dysplasias (n = 5) and head and neck squamous cell carcinoma (HNSCC) cell lines (n = 11) correlated positively with endogenous expressions of HELLS, BMI1, DNMT1 and DNMT3B and negatively with p16INK4A and involucrin. Bisulfite modification and methylation-specific promoter analysis using absolute quantitative PCR (MS-qPCR) showed that upregulation of FOXM1 significantly induced p16INK4A promoter hypermethylation (10-fold, P<0.05) in primary NOK cells. Using a non-bias genome-wide promoter methylation microarray profiling method, we revealed that aberrant FOXM1 expression in primary NOK induced a global hypomethylation pattern similar to that found in an HNSCC (SCC15) cell line. Following validation experiments using absolute qPCR, we have identified a set of differentially methylated genes, found to be inversely correlated with in vivo mRNA expression levels of clinical HNSCC tumour biopsy samples. This study provided the first evidence, using primary normal human cells and tumour tissues, that aberrant upregulation of FOXM1 orchestrated a DNA methylation signature that mimics the cancer methylome landscape, from which we have identified a unique FOXM1-induced epigenetic signature which may have clinical translational potentials as biomarkers for early cancer screening, diagnostic and/or therapeutic interventions

Pulse energy packing effects on material transport during laser processing of &lt; 1

The effects of energy pulse packing on material transport during single-pulse laser processing of silicon is studied using temporarily shaped pulses with durations from 50 to 150 ns. Six regimes of material transport were identified and disambiguated through energy packing considerations over a range of pulse durations. Energy packing has been shown to shift the interaction to energetically costlier regimes without appreciable benefit in either depth, material removal or crater morphology and quality.The authors would like to thank the UK Technology Strategy Board under project TP14/HVM/6/I/BD5665. The authors acknowledge the EPSRC Centre for Doctoral Training in Photonic Systems Development for their generous support

MicroRNAs in Renal Cell Carcinoma: Diagnostic Implications of Serum miR-1233 Levels

BACKGROUND: MicroRNA expression is altered in cancer cells, and microRNAs could serve as diagnostic/prognostic biomarker for cancer patients. Our study was designed to analyze circulating serum microRNAs in patients with renal cell carcinoma (RCC). METHODOLOGY/PRINCIPAL FINDINGS: We first explored microrna expression profiles in tissue and serum using taqman low density arrays in each six malignant and benign samples: Although 109 microRNAs were circulating at higher levels in cancer patients' serum, we identified only 36 microRNAs with up-regulation in RCC tissue and serum of RCC patients. Seven candidate microRNAs were selected for verification based on the finding of up-regulation in serum and tissue of RCC patients: miR-7-1*, miR-93, miR-106b*, miR-210, miR-320b, miR-1233 and miR-1290 levels in serum of healthy controls (n = 30) and RCC (n = 33) patients were determined using quantitative real-time PCR (TaqMan MicroRNA Assays). miR-1233 was increased in RCC patients, and thus validated in a multicentre cohort of 84 RCC patients and 93 healthy controls using quantitative real-time PCR (sensitivity 77.4%, specificity 37.6%, AUC 0.588). We also studied 13 samples of patients with angiomyolipoma or oncocytoma, whose serum miR-1233 levels were similar to RCC patients. Circulating microRNAs were not correlated with clinical-pathological parameters. CONCLUSIONS/SIGNIFICANCE: MicroRNA levels are distinctly increased in cancer patients, although only a small subset of circulating microRNAs has a tumor-specific origin. We identify circulating miR-1233 as a potential biomarker for RCC patients. Larger-scaled studies are warranted to fully explore the role of circulating microRNAs in RCC

Hippocampal Desynchronization of Functional Connectivity Prior to the Onset of Status Epilepticus in Pilocarpine-Treated Rats

Status epilepticus (SE), a pro-epileptogenic brain insult in rodent models of temporal lobe epilepsy, is successfully induced by pilocarpine in some, but not all, rats. This study aimed to identify characteristic alterations within the hippocampal neural network prior to the onset of SE. Sixteen microwire electrodes were implanted into the left hippocampus of male Sprague-Dawley rats. After a 7-day recovery period, animal behavior, hippocampal neuronal ensemble activities, and local field potentials (LFP) were recorded before and after an intra-peritoneal injection of pilocarpine (350 mg/kg). The single-neuron firing, population neuronal correlation, and coincident firing between neurons were compared between SE (n = 9) and nonSE rats (n = 12). A significant decrease in the strength of functional connectivity prior to the onset of SE, as measured by changes in coincident spike timing between pairs of hippocampal neurons, was exclusively found in SE rats. However, single-neuron firing and LFP profiles did not show a significant difference between SE and nonSE rats. These results suggest that desynchronization in the functional circuitry of the hippocampus, likely associated with a change in synaptic strength, may serve as an electrophysiological marker prior to SE in pilocarpine-treated rats