CERKL regulates autophagy via the NAD-dependent deacetylase SIRT1

<p>Macroautophagy/autophagy is an important intracellular mechanism for the maintenance of cellular homeostasis. Here we show that the <i>CERKL</i> (ceramide kinase like) gene, a retinal degeneration (RD) pathogenic gene, plays a critical role in regulating autophagy by stabilizing SIRT1. <i>In vitro</i> and <i>in vivo</i>, suppressing CERKL results in impaired autophagy. SIRT1 is one of the main regulators of acetylation/deacetylation in autophagy. In CERKL-depleted retinas and cells, SIRT1 is downregulated. ATG5 and ATG7, 2 essential components of autophagy, show a higher degree of acetylation in CERKL-depleted cells. Overexpression of SIRT1 rescues autophagy in CERKL-depleted cells, whereas CERKL loses its function of regulating autophagy in SIRT1-depleted cells, and overexpression of CERKL upregulates SIRT1. Finally, we show that CERKL directly interacts with SIRT1, and may regulate its phosphorylation at Ser27 to stabilize SIRT1. These results show that CERKL is an important regulator of autophagy and it plays this role by stabilizing the deacetylase SIRT1.</p

A Multiplexed Single-Cell CRISPR Screening Platform Enables Systematic Dissection of the Unfolded Protein Response

Functional genomics efforts face tradeoffs between number of perturbations examined and complexity of phenotypes measured. We bridge this gap with Perturb-seq, which combines droplet-based single-cell RNA-seq with a strategy for barcoding CRISPR-mediated perturbations, allowing many perturbations to be profiled in pooled format. We applied Perturb-seq to dissect the mammalian unfolded protein response (UPR) using single and combinatorial CRISPR perturbations. Two genome-scale CRISPR interference (CRISPRi) screens identified genes whose repression perturbs ER homeostasis. Subjecting ∼100 hits to Perturb-seq enabled high-precision functional clustering of genes. Single-cell analyses decoupled the three UPR branches, revealed bifurcated UPR branch activation among cells subject to the same perturbation, and uncovered differential activation of the branches across hits, including an isolated feedback loop between the translocon and IRE1α. These studies provide insight into how the three sensors of ER homeostasis monitor distinct types of stress and highlight the ability of Perturb-seq to dissect complex cellular responses.National Human Genome Research Institute (U.S.) (Grant P50HG006193

High-Resolution Tunneling Spectroscopy of Fractional Quantum Hall States

Strong interaction among electrons in two-dimensional systems in the presence of high magnetic fields gives rise to fractional quantum Hall (FQH) states that host quasi-particles with fractional charge and statistics. We perform high-resolution scanning tunneling microscopy and spectroscopy of FQH states in ultra-clean Bernal-stacked bilayer graphene (BLG) devices. Spectroscopy of FQH states shows sharp excitations in tunneling experiments that have been predicted for electron fractionalizing into bound states of quasi-particles. From our measurements and their comparison to theoretical calculations, we find energy gaps for candidate non-abelian FQH states that are larger by a factor of 5 than other related systems, making BLG an ideal setting for the manipulation of these novel quasi-particles and for the creation of a topological quantum bit. Our STM experiment also reveals previously undiscovered states in such ultra-clean samples.Comment: 5 figure

Activation of Mechanoreceptor Piezo1 Inhibits Enteric Neuronal Growth and Migration

INTRODUCTION: Dysfunction of the enteric nervous system (ENS) is linked to a myriad of gastrointestinal (GI) disorders. Piezo1 is a mechanosensitive ion channel found throughout the GI tract, but its role in the ENS is largely unknown. We hypothesize that Piezo1 plays an important role in the growth and development of the ENS. METHODS: Enteric neural crest-derived progenitor cells (ENPC) were isolated from adult mouse intestine and propagated in culture as neurospheres. ENPC-derived neurons were then subject to RESULTS: Though stretch did not cause upregulation of Piezo1 expression in enteric neurons, both stretch and Piezo1 activation produced similar alterations in neuronal morphology. Compared to control, neurite length was significantly shorter when stretched and in the presence of Piezo1 activation. Piezo1 inhibition prevented a significant reduction in neurite length in stretched neurons. Piezo1 inhibition also led to significantly increased neuronal migration, whereas Piezo1 activation resulted in significantly decreased neuronal migration and slower neuronal recovery from injury. CONCLUSION: Mechanotransduction plays an important role in regulating normal GI function. Our results suggest that the Piezo1 mechanoreceptor may play an important role in the ENS as its activation leads to decreased neuronal growth and migration. Piezo1 could be an important target for diseases of ENS dysfunction and development

Association Analysis of IL-17A and IL-17F Polymorphisms in Chinese Han Women with Breast Cancer

Background: Research into the etiology of breast cancer has recently focused on the role of the immunity and inflammation. The proinflammatory cytokines IL-17A and IL-17F can mediate inflammation and cancer. To evaluate the influences of IL-17A and IL-17F gene polymorphisms on the risk of sporadic breast cancer, a case-control study was conducted in Chinese Han women. Methodology and Principal Findings: We genotyped three single-nucleotide polymorphisms (SNPs) in IL-17A (rs2275913, rs3819025 and rs3748067) and five SNPs in IL-17F (rs7771511, rs9382084, rs12203582, rs1266828 and rs763780) to determine the haplotypes in 491 women with breast cancer and 502 healthy individuals. The genotypes were determined using the SNaPshot technique. The differences in the genotypic distribution between breast cancer patients and healthy controls were analyzed with the Chi-square test for trends. For rs2275913 in IL-17A, the frequency of the AA genotype was higher in patients than controls (P = 0.0016). The clinical features analysis demonstrated significant associations between IL-17 SNPs and tumor protein 53 (P53), progesterone receptor (PR), human epidermal growth factor receptor 2 (Her-2) and triple-negative (ER-/PR-/Her-2-) status. In addition, the haplotype analysis indicated that the frequency of the haplotype A rs2275913G rs3819025G rs3748067, located in the IL-17A linkage disequilibrium (LD) block, was higher in patients than in controls (P = 0.0471 after correction for multiple testing)