scholarly journals Nucleo-cytoplasmic trafficking regulates nuclear surface area during nuclear organogenesis

2018 ◽  
Author(s):  
Vincent Boudreau ◽  
James Hazel ◽  
Jake Sellinger ◽  
Pan Chen ◽  
Kathryn Manakova ◽  
...  
Keyword(s):  
Surface Area ◽  
Cell Size ◽  
Nuclear Export ◽  
Nuclear Surface ◽  
Reporter System ◽  
Developmental Context ◽  
Nuclear Assembly ◽  
Scaling Relationships ◽  
Nuclear Expansion

Throughout development, nuclei must be assembled following every cell division to establish a functional organelle from compact, mitotic chromatin. During nuclear organogenesis, chromatin expands to establish a nucleus of a given size seperate from the cytoplasm. Determining how nuclear organogenesis is regulated is particularly significant in the context of certain cancers in which scaling relationships between cell and nuclear sizes are not maintained. Controlling cell size in vitro using a microfluidics approach, we determined that neither nuclear volume nor surface area scale directly with cell size. Looking to explain differential nuclear scaling relationships, we developed a simple mechano-chemical mathematical model. In simulating biological perturbations in silico, our model predicted crucial roles for nucleo-cytoplasmic trafficking in regulating nuclear expansion and in restricting the recruitment of a potential nuclear surface area factor. In mammalian tissue culture, inhibiting nuclear export increased nuclear expansion rates and reduced the amount of nuclear lamin, a candidate surface area factor, being recruited to assembling nuclei, supporting our model’s predictions. Targeting the principal nuclear export component in the Drosophila syncytial embryo, Embargoed, we show that nuclear expansion rates are also increased in this developmental context, consistent with our model. Using the MS2-reporter system in fly embryos, we demonstrate a role for nuclear export in regulating transcription activation timing and dynamics, suggesting that regulating nuclear assembly is crucial for downstream nuclear function. Taken together, we propose a simple model through which nuclear organogenesis is achieved and demonstrate a role for nuclear export in regulating nuclear assembly.

scholarly journals Engineering subtilisin proteases that specifically degrade active RAS

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Yingwei Chen ◽  
Eric A. Toth ◽  
Biao Ruan ◽  
Eun Jung Choi ◽  
Richard Simmerman ◽  
...  
Keyword(s):  
Active Form ◽  
High Specificity ◽  
Kinetic Properties ◽  
Target Sequence ◽  
Reporter System ◽  
Human Cell Culture ◽  
Conserved Sequence ◽  
Cofactor Binding ◽  
Selective Proteolysis

AbstractWe describe the design, kinetic properties, and structures of engineered subtilisin proteases that degrade the active form of RAS by cleaving a conserved sequence in switch 2. RAS is a signaling protein that, when mutated, drives a third of human cancers. To generate high specificity for the RAS target sequence, the active site was modified to be dependent on a cofactor (imidazole or nitrite) and protease sub-sites were engineered to create a linkage between substrate and cofactor binding. Selective proteolysis of active RAS arises from a 2-step process wherein sub-site interactions promote productive binding of the cofactor, enabling cleavage. Proteases engineered in this way specifically cleave active RAS in vitro, deplete the level of RAS in a bacterial reporter system, and also degrade RAS in human cell culture. Although these proteases target active RAS, the underlying design principles are fundamental and will be adaptable to many target proteins.

scholarly journals Localization matters: nuclear-trapped Survivin sensitizes glioblastoma cells to temozolomide by elevating cellular senescence and impairing homologous recombination

2021 ◽  
Author(s):  
Thomas R. Reich ◽  
Christian Schwarzenbach ◽  
Juliana Brandstetter Vilar ◽  
Sven Unger ◽  
Fabian Mühlhäusler ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Nuclear Export ◽  
Cell Model ◽  
Chromosome Instability ◽  
Direct Interaction ◽  
High Grade Glioma ◽  
Strand Break ◽  
Γh2ax Foci

AbstractTo clarify whether differential compartmentalization of Survivin impacts temozolomide (TMZ)-triggered end points, we established a well-defined glioblastoma cell model in vitro (LN229 and A172) and in vivo, distinguishing between its nuclear and cytoplasmic localization. Expression of nuclear export sequence (NES)-mutated Survivin (SurvNESmut-GFP) led to impaired colony formation upon TMZ. This was not due to enhanced cell death but rather due to increased senescence. Nuclear-trapped Survivin reduced homologous recombination (HR)-mediated double-strand break (DSB) repair, as evaluated by γH2AX foci formation and qPCR-based HR assay leading to pronounced induction of chromosome aberrations. Opposite, clones, expressing free-shuttling cytoplasmic but not nuclear-trapped Survivin, could repair TMZ-induced DSBs and evaded senescence. Mass spectrometry-based interactomics revealed, however, no direct interaction of Survivin with any of the repair factors. The improved TMZ-triggered HR activity in Surv-GFP was associated with enhanced mRNA and stabilized RAD51 protein expression, opposite to diminished RAD51 expression in SurvNESmut cells. Notably, cytoplasmic Survivin could significantly compensate for the viability under RAD51 knockdown. Differential Survivin localization also resulted in distinctive TMZ-triggered transcriptional pathways, associated with senescence and chromosome instability as shown by global transcriptome analysis. Orthotopic LN229 xenografts, expressing SurvNESmut exhibited diminished growth and increased DNA damage upon TMZ, as manifested by PCNA and γH2AX foci expression, respectively, in brain tissue sections. Consequently, those mice lived longer. Although tumors of high-grade glioma patients expressed majorly nuclear Survivin, they exhibited rarely NES mutations which did not correlate with survival. Based on our in vitro and xenograft data, Survivin nuclear trapping would facilitate glioma response to TMZ.

scholarly journals Simple Equations Pertaining to the Particle Number and Surface Area of Metallic, Polymeric, Lipidic and Vesicular Nanocarriers

2021 ◽  
Vol 89 (2) ◽  
pp. 15
Author(s):  
M. R. Mozafari ◽  
E. Mazaheri ◽  
K. Dormiani
Keyword(s):  
Drug Delivery ◽  
Surface Area ◽  
Particle Number ◽  
Analytical Techniques ◽  
Metallic Particles ◽  
Nutraceutical Compounds ◽  
Mathematical Formulas ◽  
Simple Equations

Introduction: Bioactive encapsulation and drug delivery systems have already found their way to the market as efficient therapeutics to combat infections, viral diseases and different types of cancer. The fields of food fortification, nutraceutical supplementation and cosmeceuticals have also been getting the benefit of encapsulation technologies. Aim: Successful formulation of such therapeutic and nutraceutical compounds requires thorough analysis and assessment of certain characteristics including particle number and surface area without the need to employ sophisticated analytical techniques. Solution: Here we present simple mathematical formulas and equations used in the research and development of drug delivery and controlled release systems employed for bioactive encapsulation and targeting the sites of infection and cancer in vitro and in vivo. Systems covered in this entry include lipidic vesicles, polymeric capsules, metallic particles as well as surfactant- and tocopherol-based micro- and nanocarriers.

scholarly journals Newly Emerging Airborne Pollutants: Current Knowledge of Health Impact of Micro and Nanoplastics

2021 ◽  
Vol 18 (6) ◽  
pp. 2997
Author(s):  
Alessio Facciolà ◽  
Giuseppa Visalli ◽  
Marianna Pruiti Ciarello ◽  
Angela Di Pietro
Keyword(s):  
Surface Area ◽  
Current Knowledge ◽  
Oxidative Degradation ◽  
Health Impact ◽  
Outdoor Exposure ◽  
Environmental Matrices ◽  
Potential Health ◽  
Bodily Fluids

Plastics are ubiquitous persistent pollutants, forming the most representative material of the Anthropocene. In the environment, they undergo wear and tear (i.e., mechanical fragmentation, and slow photo and thermo-oxidative degradation) forming secondary microplastics (MPs). Further fragmentation of primary and secondary MPs results in nanoplastics (NPs). To assess potential health damage due to human exposure to airborne MPs and NPs, we summarize the evidence collected to date that, however, has almost completely focused on monitoring and the effects of airborne MPs. Only in vivo and in vitro studies have assessed the toxicity of NPs, and a standardized method for their analysis in environmental matrices is still missing. The main sources of indoor and outdoor exposure to these pollutants include synthetic textile fibers, rubber tires, upholstery and household furniture, and landfills. Although both MPs and NPs can reach the alveolar surface, the latter can pass into the bloodstream, overcoming the pulmonary epithelial barrier. Despite the low reactivity, the number of surface area atoms per unit mass is high in MPs and NPs, greatly enhancing the surface area for chemical reactions with bodily fluids and tissue in direct contact. This is proven in polyvinyl chloride (PVC) and flock workers, who are prone to persistent inflammatory stimulation, leading to pulmonary fibrosis or even carcinogenesis.

scholarly journals CTNI-18. FINAL RESULTS OF A PHASE 2 STUDY OF EFFICACY, SAFETY AND INTRATUMORAL PHARMACOKINETICS (PK) OF SELINEXOR MONOTHERAPY IN RECURRENT GLIOBLASTOMA (rGBM)

2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii46-ii46
Author(s):  
Andrew Lassman ◽  
Patrick Wen ◽  
Martin van den Bent ◽  
Scott Plotkin ◽  
Annemiek Walenkamp ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Phase 1 ◽  
Progression Free Survival ◽  
Median Number ◽  
Recurrent Glioblastoma ◽  
Phase 2 ◽  
Nuclear Retention ◽  
Phase 2 Trial ◽  
Human Gbm

Abstract BACKGROUND Selinexor is an FDA-approved first-in-class, oral selective nuclear export inhibitor which forces nuclear retention of many tumor suppressor proteins. METHODS We conducted a phase 2 trial of selinexor monotherapy for adults with recurrent GBM including a surgical arm to explore intratumoral PK and 3 medical arms to optimize dosing. Prior treatment with radiotherapy and temozolomide was required; prior bevacizumab was exclusionary. The primary endpoint was 6-month progression-free survival (6mPFS) rate. RESULTS Selinexor administered ~2 hours pre-operatively yieleded average intratumoral concentration (136 nM, n=6) comparable to the in vitro IC50 (130 nM) from 7 primary human GBM cell lines. Among all 68 patients accrued to 3 medical arms (~85 mg BIW, n=24; 60 mg BIW, n=14; 80 mg QW, n=30), median age was 56 years (21–78). Median number of prior lines of therapies was 2 (1–7). At 80 mg QW, 28% patients were progression-free at the end of cycle 6; the 6mPFS was 17%; disese control rate by RANO was 37% (1 CR, 2 PRs, 7 SD) among 27 evaluable patients; responses were durable (median 11.1 months), and treatment lasted for 442, 547 and 1282 days in 3 responders, as of data lock, with one responder remaining on treatment off study; median overall survival was 10.2 months with 95% CI (7.0, 15.4). The ~85 mg BIW-schedule was abandoned due to poor tolerability. The related adverse events (all grades) in patients on ~85 mg BIW/60 mg BIW/80 mg QW were nausea (41.7%/64.3%/66.7%), fatigue (70.8%/71.4%/50.0%), neutropenia (29.2%/14.3%/33.3%), decreased appetite (45.8%/71.4%/26.7%), thrombocytopenia (66.7%/28.6%/23.3%) and weight loss (16.7%,/42.9%/6.7%). CONCLUSION Selinexor monotherapy demonstrated encouraging intratumoral penetration and efficacy, with durable disease control in rGBM. Monotherapy dose at 80 mg QW is recommended for further development in rGBM. A phase 1/2 study of combination therapy for newly diagnosed or rGBM has been initiated (NCT04421378).

scholarly journals Phosphorylation of Serine 11 and Serine 92 as New Positive Regulators of Human Snail1 Function: Potential Involvement of Casein Kinase-2 and the cAMP-activated Kinase Protein Kinase A

2010 ◽  
Vol 21 (2) ◽  
pp. 244-253 ◽  
Author(s):  
Matthew Reid MacPherson ◽  
Patricia Molina ◽  
Serhiy Souchelnytskyi ◽  
Christer Wernstedt ◽  
Jorge Martin-Pérez ◽  
...  
Keyword(s):  
Nuclear Export ◽  
Tumor Metastasis ◽  
Epithelial Mesenchymal Transition ◽  
Cop9 Signalosome ◽  
Mesenchymal Transition ◽  
Depth Analysis ◽  
Positive Regulators

Snail1 is a major factor for epithelial-mesenchymal transition (EMT), an important event in tumor metastasis and in other pathologies. Snail1 is tightly regulated at transcriptional and posttranscriptional levels. Control of Snail1 protein stability and nuclear export by GSK3β phosphorylation is important for Snail1 functionality. Stabilization mechanisms independent of GSK3β have also been reported, including interaction with LOXL2 or regulation of the COP9 signalosome by inflammatory signals. To get further insights into the role of Snail1 phosphorylation, we have performed an in-depth analysis of in vivo human Snail1 phosphorylation combined with mutational studies. We identify new phosphorylation sites at serines 11, 82, and 92 and confirmed previously suggested phosphorylations at serine 104 and 107. Serines 11 and 92 participate in the control of Snail1 stability and positively regulate Snail1 repressive function and its interaction with mSin3A corepressor. Furthermore, serines 11 and 92 are required for Snail1-mediated EMT and cell viability, respectively. PKA and CK2 have been characterized as the main kinases responsible for in vitro Snail1 phosphorylation at serine 11 and 92, respectively. These results highlight serines 11 and 92 as new players in Snail1 regulation and suggest the participation of CK2 and PKA in the modulation of Snail1 functionality.

Scaling relationships between lake surface area and catchment area

2020 ◽  
Vol 82 (3) ◽  
Author(s):  
Jonathan A. Walter ◽  
Rachel Fleck ◽  
Michael L. Pace ◽  
Grace M. Wilkinson
Keyword(s):  
Surface Area ◽  
Catchment Area ◽  
Lake Surface ◽  
Scaling Relationships ◽  
Lake Surface Area

Effects of fetal corticosteroid treatments on postnatal surfactant function in preterm lambs

1995 ◽  
Vol 79 (3) ◽  
pp. 846-851 ◽  
Author(s):  
T. Ueda ◽  
M. Ikegami ◽  
D. Polk ◽  
K. Mizuno ◽  
A. Jobe
Keyword(s):  
Surface Area ◽  
Dynamic Compliance ◽  
Alveolar Space ◽  
Prenatal Treatment ◽  
Ultrasound Guided ◽  
Functional Characteristics ◽  
Arterial Pco2 ◽  
Alveolar Surfactant ◽  
Pool Sizes

Effects of prenatal corticosteroid on the properties of surfactant have not previously been evaluated. A single ultrasound-guided fetal injection with 0.5 mg/kg betamethasone 48 h before delivery of preterm lambs at 134- to 135-days gestation improved oxygenation, lowered the ventilatory pressures required to maintain arterial PCO2 between 30 and 40 Torr and decreased the protein leak of albumin from the intravascular to the alveolar space. This dose of glucocorticoid did not alter surfactant-saturated phosphatidylcholine pool sizes in the airspaces of preterm lambs. However, the treatment changed the characteristics of the surfactant recovered from the ventilated preterm lambs. The in vitro conversion from heavy to light subtype surfactant decreased from 59% for the saline-treated lambs to 37% for the corticosteroid-treated lambs after 180 min of surface area cycling (P < 0.02). Surfactant from the corticosteroid-treated lambs also increased the dynamic compliance of preterm surfactant-deficient rabbits more than did surfactant from the saline-treated lambs (P < 0.05). Prenatal treatment of preterm lambs with betamethasone improved the functional characteristics of surfactant without significant effects on the alveolar surfactant pool sizes.

scholarly journals Novel activities by ebolavirus and marburgvirus interferon antagonists revealed using a standardized in vitro reporter system

Virology ◽  
2017 ◽  
Vol 501 ◽  
pp. 147-165 ◽  
Author(s):  
Jonathan C. Guito ◽  
César G. Albariño ◽  
Ayan K. Chakrabarti ◽  
Jonathan S. Towner
Keyword(s):  
Reporter System ◽  
Interferon Antagonists
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