681 research outputs found
AFLOW-ML: A RESTful API for machine-learning predictions of materials properties
Machine learning approaches, enabled by the emergence of comprehensive
databases of materials properties, are becoming a fruitful direction for
materials analysis. As a result, a plethora of models have been constructed and
trained on existing data to predict properties of new systems. These powerful
methods allow researchers to target studies only at interesting materials
\unicode{x2014} neglecting the non-synthesizable systems and those without
the desired properties \unicode{x2014} thus reducing the amount of resources
spent on expensive computations and/or time-consuming experimental synthesis.
However, using these predictive models is not always straightforward. Often,
they require a panoply of technical expertise, creating barriers for general
users. AFLOW-ML (AFLOW achine
earning) overcomes the problem by streamlining the use
of the machine learning methods developed within the AFLOW consortium. The
framework provides an open RESTful API to directly access the continuously
updated algorithms, which can be transparently integrated into any workflow to
retrieve predictions of electronic, thermal and mechanical properties. These
types of interconnected cloud-based applications are envisioned to be capable
of further accelerating the adoption of machine learning methods into materials
development.Comment: 10 pages, 2 figure
Esterase mutation is a mechanism of resistance to antimalarial compounds
Pepstatin is a potent peptidyl inhibitor of various malarial aspartic proteases, and also has parasiticidal activity. Activity of pepstatin against cultured Plasmodium falciparum is highly variable depending on the commercial source. Here we identify a minor contaminant (pepstatin butyl ester) as the active anti-parasitic principle. We synthesize a series of derivatives and characterize an analogue (pepstatin hexyl ester) with low nanomolar activity. By selecting resistant parasite mutants, we find that a parasite esterase, PfPARE (P. falciparum Prodrug Activation and Resistance Esterase) is required for activation of esterified pepstatin. Parasites with esterase mutations are resistant to pepstatin esters and to an open source antimalarial compound, MMV011438. Recombinant PfPARE hydrolyses pepstatin esters and de-esterifies MMV011438. We conclude that (1) pepstatin is a potent but poorly bioavailable antimalarial; (2) PfPARE is a functional esterase that is capable of activating prodrugs; (3) Mutations in PfPARE constitute a mechanism of antimalarial resistance
Estradiol suppresses tissue androgens and prostate cancer growth in castration resistant prostate cancer
<p>Abstract</p> <p>Background</p> <p>Estrogens suppress tumor growth in prostate cancer which progresses despite anorchid serum androgen levels, termed castration resistant prostate cancers (CRPC), although the mechanisms are unclear. We hypothesize that estrogen inhibits CRPC in anorchid animals by suppressing tumoral androgens, an effect independent of the estrogen receptor.</p> <p>Methods</p> <p>The human CRPC xenograft LuCaP 35V was implanted into orchiectomized male SCID mice and established tumors were treated with placebo, 17β-estradiol or 17β-estradiol and estrogen receptor antagonist ICI 182,780. Effects of 17β-estradiol on tumor growth were evaluated and tissue testosterone (T) and dihydrotestosterone (DHT) evaluated by mass spectrometry.</p> <p>Results</p> <p>Treatment of LuCaP 35V with 17β-estradiol slowed tumor growth compared to controls (tumor volume at day 21: 785 ± 81 mm<sup>3 </sup>vs. 1195 ± 84 mm<sup>3</sup>, p = 0.002). Survival was also significantly improved in animals treated with 17β-estradiol (p = 0.03). The addition of the estrogen receptor antagonist ICI 182,780 did not significantly change survival or growth. 17β-estradiol in the presence and absence of ICI 182,780 suppressed tumor testosterone (T) and dihydrotestosterone (DHT) as assayed by mass spectrometry. Tissue androgens in placebo treated LuCaP 35V xenografts were; T = 0.71 ± 0.28 pg/mg and DHT = 1.73 ± 0.36 pg/mg. In 17β-estradiol treated LuCaP35V xenografts the tissue androgens were, T = 0.20 ± 0.10 pg/mg and DHT = 0.15 ± 0.15 pg/mg, (p < 0.001 vs. controls). Levels of T and DHT in control liver tissue were < 0.2 pg/mg.</p> <p>Conclusions</p> <p>CRPC in anorchid animals maintains tumoral androgen levels despite castration. 17β-estradiol significantly suppressed tumor T and DHT and inhibits growth of CRPC in an estrogen receptor independent manner. The ability to manipulate tumoral androgens will be critical in the development and testing of agents targeting CRPC through tissue steroidogenesis.</p
Aligned electrospun nanofibers specify the direction of dorsal root ganglia neurite growth
Nerve injury, a significant cause of disability, may be treated more effectively using nerve guidance channels containing longitudinally aligned fibers. Aligned, electrospun nanofibers direct the neurite growth of immortalized neural stem cells, demonstrating potential for directing regenerating neurites. However, no study of neurite guidance on these fibers has yet been performed with primary neurons. Here, we examined neurites from dorsal root ganglia explants on electrospun poly- L -lactate nanofibers of high, intermediate, and random alignment. On aligned fibers, neurites grew radially outward from the ganglia and turned to follow the fibers upon contact. Neurite guidance was robust, with neurites never leaving the fibers to grow on the surrounding cover slip. To compare the alignment of neurites to that of the nanofiber substrates, Fourier methods were used to quantify the alignment. Neurite alignment, however striking, was inferior to fiber alignment on all but the randomly aligned fibers. Neurites on highly aligned substrates were 20 and 16% longer than neurites on random and intermediate fibers, respectively. Schwann cells on fibers assumed a very narrow morphology compared to those on the surrounding coverslip. The robust neurite guidance demonstrated here is a significant step toward the use of aligned, electrospun nanofibers for nerve regeneration. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/57401/1/31285_ftp.pd
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PlexinD1 is a driver and a therapeutic target in advanced prostate cancer.
Aggressive prostate cancer (PCa) variants associated with androgen receptor signaling inhibitor (ARSI) resistance and metastasis remain poorly understood. Here, we identify the axon guidance semaphorin receptor PlexinD1 as a crucial driver of cancer aggressiveness in metastatic castration-resistant prostate cancer (CRPC). High PlexinD1 expression in human PCa is correlated with adverse clinical outcomes. PlexinD1 critically maintains CRPC aggressive behaviors in vitro and in vivo, and confers stemness and cellular plasticity to promote multilineage differentiation including a neuroendocrine-like phenotype for ARSI resistance. Mechanistically, PlexinD1 is upregulated upon relief of AR-mediated transcriptional repression of PlexinD1 under ARSI treatment, and subsdquently transactivates ErbB3 and cMet via direct interaction, which triggers the ERK/AKT pathways to induce noncanonical Gli1-dictated Hedgehog signaling, facilitating the growth and plasticity of PCa cells. Blockade of PlexinD1 by the protein inhibitor D1SP restricted CRPC growth in multiple preclinical models. Collectively, these findings characterize PlexinD1s contribution to PCa progression and offer a potential PlexinD1-targeted therapy for advanced PCa
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Brain aging shows nonlinear transitions, suggesting a midlife critical window for metabolic intervention.
Understanding the key drivers of brain aging is essential for effective prevention and treatment of neurodegenerative diseases. Here, we integrate human brain and physiological data to investigate underlying mechanisms. Functional MRI analyses across four large datasets (totaling 19,300 participants) show that brain networks not only destabilize throughout the lifetime but do so along a nonlinear trajectory, with consistent temporal landmarks of brain aging starting in midlife (40s). Comparison of metabolic, vascular, and inflammatory biomarkers implicate dysregulated glucose homeostasis as the driver mechanism for these transitions. Correlation between the brains regionally heterogeneous patterns of aging and gene expression further supports these findings, selectively implicating GLUT4 (insulin-dependent glucose transporter) and APOE (lipid transport protein). Notably, MCT2 (a neuronal, but not glial, ketone transporter) emerges as a potential counteracting factor by facilitating neurons energy uptake independently of insulin. Consistent with these results, an interventional study of 101 participants shows that ketones exhibit robust effects in restabilizing brain networks, maximized from ages 40 to 60, suggesting a midlife critical window for early metabolic intervention
Concert recording 2015-12-06
[Track 01]. Lachen und Weinen / Franz Schubert -- Zitronenfalter im April / Hugo Wolf -- [Track 02]. Ganymed / Franz Schubert -- [Track 03]. Gesang Weylas / Hugo Wolf -- [Track 04]. An Silvia / Franz Schubert -- [Track 05]. Der Gärtner / Hugo Wolf -- [Track 06]. Gott im Frühling / Franz Schubert -- [Track 07]. Elfenlied / Hugo Wolf -- [Track 08]. Schäfers Klagelied / Franz Schubert -- [Track 09]. Verborgenheit / Hugo Wolf -- [Track 10]. Gretchens Bitte / Franz Schubert -- [Track 11]. Die Zigeunerin / Hugo Wolf -- [Track 12]. Liebesbotschaft / Franz Schubert -- [Track 13]. In dem Schatten meiner Locken / Hugo Wolf -- [Track 14]. Die junge Nonne / Franz Schubert -- [Track 15]. Nimmersatte Liebe / Hugo Wolf -- [Track 16]. Liebe schwärmt auf allen Wegen / Franz Schubert -- [Track 17]. Er ist\u27s / Hugo Wolf -- [Track 18]. Der Musensohn / Franz Schubert -- [Track 19]. Storchenbotschaft / Hugo Wolf
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Plexin D1 emerges as a novel target in the development of neural lineage plasticity in treatment-resistant prostate cancer
Treatment-induced neuroendocrine prostate cancer (t-NEPC) often arises from adenocarcinoma via lineage plasticity in response to androgen receptor signaling inhibitors, such as enzalutamide. However, the specific regulators and targets involved in the transition to NEPC are not well understood. Plexin D1 (PLXND1) is a cellular receptor of the semaphorin (SEMA) family that plays important roles in modulating the cytoskeleton and cell adhesion. Here, we found that PLXND1 was highly expressed and positively correlated with neuroendocrine markers in patients with NEPC. High PLXND1 expression was associated with poorer prognosis in prostate cancer patients. Additionally, PLXND1 was upregulated and negatively regulated by androgen receptor signaling in enzalutamide-resistant cells. Knockdown or knockout of PLXND1 inhibited neural lineage pathways, thereby suppressing NEPC cell proliferation, patient derived xenograft (PDX) tumor organoid viability, and xenograft tumor growth. Mechanistically, the heat shock protein 70 (HSP70) regulated PLXND1 protein stability through degradation, and inhibition of HSP70 decreased PLXND1 expression and NEPC organoid growth. In summary, our findings indicate that PLXND1 could serve as a promising therapeutic target and molecular marker for NEPC
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Alteration in expression and subcellular localization of the androgen receptor- regulated FAM111A protease is associated with emergence of castration resistant prostate cancer
The androgen receptor (AR) is a pivotal regulator of growth and survival of prostate cancer (PCa) and the majority of lethal castration-resistant prostate cancers (CRPC) remain reliant on AR signaling. PCa exhibits variability in progression and responses to treatment suggesting genetic heterogeneity. Two independent studies identified PCa predisposing single nucleotide polymorphisms (SNPs) within the FAM111A protease gene, but the mechanistic basis of this association remained elusive. Our in vitro and in vivo studies uncovered that AR represses FAM111A in castration sensitive and resistant cells via an AR binding site within the FAM111A gene. FAM111A levels are significantly lower in matched castration-resistant than in castration-sensitive cells and xenografts, and lower in metastatic lesions than in primary tumors. We discovered that FAM111A is AR-repressed in castration sensitive PCa xenograft and multiple PCa cells. Additionally, FAM111A subcellular localization changes dramatically with acquisition of castration resistance, where in castration sensitive cells FAM111A is predominantly in the nucleoli, but with castration resistance it becomes more dispersed in the nucleus and in the cytoplasm. FAM111A depletion in castration sensitive and resistant cells enhances the efficacy of PARP1 inhibitors olaparib and niraparib, consistent with its role in DNA repair. Moreover, FAM111A depletion reduces AR target gene prostate specific antigen (PSA) and transmembrane serine protease 2 (TMPRSS2) transcription, indicating that FAM111A modulates AR-dependent gene expression forming a FAM111A-AR co-regulatory loop in PCa. Our studies argue that AR-dependent FAM111A regulation modulates PCa gene expression, acquisition of castration resistance, and sensitivity to agents that target DNA damage repair
Chemokine receptor CXCR7 activates Aurora Kinase A and promotes neuroendocrine prostate cancer growth
CXCR7 is an atypical chemokine receptor that recruits β-arrestin (ARRB2) and internalizes into clathrin-coated intracellular vesicles where the complex acts as a scaffold for cytoplasmic kinase assembly and signal transduction. Here, we report that CXCR7 was elevated in the majority of prostate cancer (PCa) cases with neuroendocrine features (NEPC). CXCR7 markedly induced mitotic spindle and cell cycle gene expression. Mechanistically, we identified Aurora Kinase A (AURKA), a key regulator of mitosis, as a novel target that was bound and activated by the CXCR7-ARRB2 complex. CXCR7 interacted with proteins associated with microtubules and golgi, and, as such, the CXCR7-ARRB2-containing vesicles trafficked along the microtubules to the pericentrosomal golgi apparatus, where the complex interacted with AURKA. Accordingly, CXCR7 promoted PCa cell proliferation and tumor growth, which was mitigated by AURKA inhibition. In summary, our study reveals a critical role of CXCR7-ARRB2 in interacting and activating AURKA, which can be targeted by AURKA inhibitors to benefit a subset of patients with NEPC
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