Faculty Bibliography

Dysregulation of amyloid-beta (Abeta) metabolism is critical for Alzheimer's disease (AD) pathogenesis. Mounting evidence suggests that apolipoprotein E (ApoE) is involved in Abeta metabolism. ATP-binding cassette transporter A1 (ABCA1) is a key regulator of ApoE lipidation, which affects Abeta levels. Therefore, identifying regulatory mechanisms of ABCA1 expression in the brain may provide new therapeutic targets for AD. Here, we demonstrate that microRNA-33 (miR-33) regulates ABCA1 and Abeta levels in the brain. Overexpression of miR-33 impaired cellular cholesterol efflux and dramatically increased extracellular Abeta levels by promoting Abeta secretion and impairing Abeta clearance in neural cells. In contrast, genetic deletion of mir-33 in mice dramatically increased ABCA1 levels and ApoE lipidation, but it decreased endogenous Abeta levels in cortex. Most importantly, pharmacological inhibition of miR-33 via antisense oligonucleotide specifically in the brain markedly decreased Abeta levels in cortex of APP/PS1 mice, representing a potential therapeutic strategy for AD. SIGNIFICANCE STATEMENT: Brain lipid metabolism, in particular Apolipoprotein E (ApoE) lipidation, is critical to Abeta metabolism and Alzheimer's disease (AD). Brain lipid metabolism is largely separated from the periphery due to blood-brain barrier and different repertoire of lipoproteins. Therefore, identifying the novel regulatory mechanism of brain lipid metabolism may provide a new therapeutic strategy for AD. Although there have been studies on brain lipid metabolism, its regulation, in particular by microRNAs, is relatively unknown. Here, we demonstrate that inhibition of microRNA-33 increases lipidation of brain ApoE and reduces Abeta levels by inducing ABCA1. We provide a unique approach for AD therapeutics to increase ApoE lipidation and reduce Abeta levels via pharmacological inhibition of microRNA in vivo.

PURPOSE: Brain metastasis is the major cause of mortality among melanoma patients. A molecular prognostic test that can reliably stratify patients at initial melanoma diagnosis by risk of developing brain metastasis may inform the clinical management of these patients. EXPERIMENTAL DESIGN: We performed a retrospective, cohort-based study analyzing genome-wide and targeted microRNA expression profiling of primary melanoma tumors of three patient cohorts (n= 92, n= 119, n= 45) with extensive clinical follow up. We used Cox regression analysis to establish a microRNA-based signature that improves the ability of the current clinicopathologic staging system to predict the development of brain metastasis. RESULTS: Our analyses identified a 4-microRNA (miR-150-5p, miR-15b-5p, miR-16-5p, and miR-374b-3p) prognostic signature that, in combination with stage, distinguished primary melanomas that metastasized to the brain from non-recurrent and non-brain-metastatic primary tumors (training cohort: C-index=81.4%, validation cohort: C-index=67.4%, independent cohort: C-index=76.9%). Corresponding Kaplan-Meier curves of high- vs. low-risk patients displayed a clear separation in brain-metastasis-free and overall survival (training: p<0.001, p<0.001, validation: p=0.033, p=0.007, independent: p=0.021, p=0.022, respectively). Finally, of the microRNA in the prognostic model, we found that the expression of a key lymphocyte miRNA, miR-150-5p, which is less abundant in primary melanomas metastatic to brain, correlated with presence of CD45+ tumor infiltrating lymphocytes. CONCLUSIONS: A prognostic assay based on the described miRNA expression signature combined with the currently used staging criteria may improve accuracy of primary melanoma patient prognoses and aid clinical management of patients, including selection for adjuvant treatment or clinical trials of adjuvant therapies.

Invariant natural killer T (iNKT) cells recognize glycolipids as antigens and diversify into NKT1 (IFN-gamma), NKT2 (IL-4), and NKT17 (IL-17) functional subsets while developing in the thymus. Mechanisms that govern the balance between these functional subsets are poorly understood due, partly, to the lack of distinguishing surface markers. Here we identify the heparan sulfate proteoglycan syndecan-1 (sdc1) as a specific marker of naive thymic NKT17 cells in mice and show that sdc1 deficiency significantly increases thymic NKT17 cells at the expense of NKT1 cells, leading to impaired iNKT cell-derived IFN-gamma, both in vitro and in vivo. Using surface expression of sdc1 to identify NKT17 cells, we confirm differential tissue localization and interstrain variability of NKT17 cells, and reveal that NKT17 cells express high levels of TCR-beta, preferentially use Vbeta8, and are more highly sensitive to a-GalCer than to CD3/CD28 stimulation. These findings provide a novel, noninvasive, simple method for identification, and viable sorting of naive NKT17 cells from unmanipulated mice, and suggest that sdc1 expression negatively regulates homeostasis in iNKT cells. In addition, these findings lay the groundwork for investigating the mechanisms by which sdc1 regulates NKT17 cells.

PURPOSE: The effect of age on telomere length heterogeneity in men has not been studied previously. Our aims were to determine the relationship between variation in sperm telomere length (STL), men's age, and semen parameters in spermatozoa from men undergoing in vitro fertilization (IVF) treatment. METHODS: To perform this prospective cross-sectional pilot study, telomere length was estimated in 200 individual spermatozoa from men undergoing IVF treatment at the NYU Fertility Center. A novel single-cell telomere content assay (SCT-pqPCR) measured telomere length in individual spermatozoa. RESULTS: Telomere length among individual spermatozoa within an ejaculate varies markedly and increases with age. Older men not only have longer STL but also have more variable STL compared to younger men. STL from samples with normal semen parameters was significantly longer than that from samples with abnormal parameters, but STL did not differ between spermatozoa with normal versus abnormal morphology. CONCLUSION: The marked increase in STL heterogeneity as men age is consistent with a role for ALT during spermatogenesis. No data have yet reported the effect of age on STL heterogeneity. Based on these results, future studies should expand this modest sample size to search for molecular evidence of ALT in human testes during spermatogenesis.

Neuronal cell death, in neurodegenerative disorders, is mediated through a spectrum of biological processes. Excessive amounts of free radicals, such as reactive oxygen species (ROS), has detrimental effects on neurons leading to cell damage via peroxidation of unsaturated fatty acids in the cell membrane. Edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) has been used for neurological recovery in several countries, including Japan and China, and it has been suggested that Edaravone may have cytoprotective effects in neurodegeneration. Edaravone protects nerve cells in the brain by reducing ROS and inhibiting apoptosis. To gain further insight into the cytoprotective effects of Edaravone against oxidative stress condition we have performed comparative two-dimensional gel electrophoresis (2DE)-based proteomic analyses on SH-SY5Y neuroblastoma cells exposed to oxidative stress and in combination with Edaravone. We showed that Edaravone can reverse the cytotoxic effects of H2O2 through its specific mechanism. We observed that oxidative stress changes metabolic pathways and cytoskeletal integrity. Edaravone seems to reverse the H2O2-mediated effects at both the cellular and protein level via induction of Peroxiredoxin-2.

Neither breakpoints (BPs) nor epidemiological cutoff values (ECVs) have been established for Candida spp. with anidulafungin, caspofungin, and micafungin when using the Sensititre YeastOne (SYO) broth dilution colorimetric method. In addition, reference caspofungin MICs have so far proven to be unreliable. Candida species wild-type (WT) MIC distributions (for microorganisms in a species/drug combination with no detectable phenotypic resistance) were established for 6,007 Candida albicans, 186 C. dubliniensis, 3,188 C. glabrata complex, 119 C. guilliermondii, 493 C. krusei, 205 C. lusitaniae, 3,136 C. parapsilosis complex, and 1,016 C. tropicalis isolates. SYO MIC data gathered from 38 laboratories in Australia, Canada, Europe, Mexico, New Zealand, South Africa, and the United States were pooled to statistically define SYO ECVs. ECVs for anidulafungin, caspofungin, and micafungin encompassing >/=97.5% of the statistically modeled population were, respectively, 0.12, 0.25, and 0.06 mug/ml for C. albicans, 0.12, 0.25, and 0.03 mug/ml for C. glabrata complex, 4, 2, and 4 mug/ml for C. parapsilosis complex, 0.5, 0.25, and 0.06 mug/ml for C. tropicalis, 0.25, 1, and 0.25 mug/ml for C. krusei, 0.25, 1, and 0.12 mug/ml for C. lusitaniae, 4, 2, and 2 mug/ml for C. guilliermondii, and 0.25, 0.25, and 0.12 mug/ml for C. dubliniensis. Species-specific SYO ECVs for anidulafungin, caspofungin, and micafungin correctly classified 72 (88.9%), 74 (91.4%), 76 (93.8%), respectively, of 81 Candida isolates with identified fks mutations. SYO ECVs may aid in detecting non-WT isolates with reduced susceptibility to anidulafungin, micafungin, and especially caspofungin, since testing the susceptibilities of Candida spp. to caspofungin by reference methodologies is not recommended.

Curly, described almost a century ago, is one of the most frequently used markers in Drosophila genetics. Despite this the molecular identity of Curly has remained obscure. Here we show that Curly mutations arise in the gene dual oxidase (duox), which encodes a reactive oxygen species (ROS) generating NADPH oxidase. Using Curly mutations and RNA interference (RNAi), we demonstrate that Duox autonomously stabilizes the wing on the last day of pupal development. Through genetic suppression studies, we identify a novel heme peroxidase, Curly Su (Cysu) that acts with Duox to form the wing. Ultrastructural analysis suggests that Duox and Cysu are required in the wing to bond and adhere the dorsal and ventral cuticle surfaces during its maturation. In Drosophila, Duox is best known for its role in the killing of pathogens by generating bactericidal ROS. Our work adds to a growing number of studies suggesting that Duox's primary function is more structural, helping to form extracellular and cuticle structures in conjunction with peroxidases.

Mutations in genes encoding Isocitrate Dehydrogenase (IDH) isoforms are found in80%of low-grade gliomas (LGGs). Sequencing of LGGs has revealed branching cancer genetics; mutant IDH1 astrocytomas contain p53 and ATRX loss of function mutations, while IDH1-mutated oligodendrogliomas have a different set of mutations that includes chr 1p/19q co-deletion. The IDH mutation is a gain-of-function change at its catalytic core that results in the production of (R)-2-hydroxyglutarate, an oncometabolite, which causes characteristic DNA and histone hypermethylation changes that may contribute to tumorigenesis. Mouse models have thus far failed to demonstrate the role of IDH1 mutations in LGG formation. To test the hypothesis that mutant IDH1 is a driver of gliomagenesis, we use human embryonic stem cell (hESC)-derived neural stem cells (NSCs) to overexpress mutant IDH1 protein in combination with p53 and ATRX knockdown. We have generated twelve NSC lines that harbor combinations of mutant IDH1, wt IDH1 or an empty vector, in combination with ATRX and/or p53 knockdown. Our preliminary data indicate that mutantIDH1 does not alter the proliferative capacity of NSCs, as shown by cell cycle analysis and Ki67 staining, but paradoxically increases their apoptotic rate (15.8% vs 5.9% n = 4), a phenotype that is exacerbated by ATRX knockdown, as detected by annexin V and TUNEL staining (17.7% vs 2.6% n = 3). shRNA-mediated knockdown of p53 salvages the pro-apoptotic phenotype of mutant IDH1 and ATRX NSCs. Furthermore, initial observations suggest that mutant IDH1 biases NSCs toward glial fates, as evidenced by upregulation of the CD44 cell surface marker. We are currently testing the effects of IDH1 mutation on i) NSC differentiation to astrocytic and neuronal lineages, ii) NSC metabolism via metabolomics profiling and iii) in vivo tumorigenesis. We propose that mutant IDH1 alters the differentiation program of human NSCs toward glial rather than neuronal fates

OBJECTIVE: Highly publicized incidents in which people with apparent mental illnesses use guns to victimize strangers have important implications for public views of people with mental illnesses and the formation of mental health and gun policy. The study aimed to provide more data about this topic. METHODS: MacArthur Violence Risk Assessment Study data were analyzed to determine the prevalence of violence by 951 patients after discharge from a psychiatric hospital, including gun violence, violence toward strangers, and gun violence toward strangers. RESULTS: Two percent of patients committed a violent act involving a gun, 6% committed a violent act involving a stranger, and 1% committed a violent act involving both a gun and a stranger. CONCLUSIONS: When public perceptions and policies regarding mental illness are shaped by highly publicized but infrequent instances of gun violence toward strangers, they are unlikely to help people with mental illnesses or to improve public safety.