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1.
J Exp Biol ; 2020 Jan 30.
Artigo em Inglês | MEDLINE | ID: mdl-32001544

RESUMO

Composites, both natural and synthetic, achieve novel functionality by combining two or more constituent materials. For example, the earliest adhesive silk in spider webs - cribellate silk - is composed of stiff axial fibers and coiled fibers surrounded by hundreds of sticky cribellate nanofibrils. Yet little is known of how fiber types interact to enable capture of insect prey with cribellate silk. To understand the roles of each constituent fiber during prey capture, we compared the tensile performance of native-state and manipulated threads produced by Psechrus clavis, and the adhesion of native threads along a smooth surface and hairy bee thorax. We found that the coiled fiber increases the work to fracture of the entire cribellate thread by up to 20-fold. We also found that the axial fiber breaks multiple times during deformation, an unexpected observation that indicates: i) the axial fiber continues to contribute work even after breakage, ii) the cribellate nanofibrils may perform a previously unidentified role as a binder material that distributes forces throughout the thread. Work of adhesion increased on surfaces with more surface structures (hairy bee thorax) corresponding to increased deformation of the coiled fiber. Together, our observations highlight how the synergistic interactions among the constituents of this natural composite adhesive enhance functionality. These highly extensible threads may serve to expose additional cribellate nanofibrils to form attachment points with prey substrata while also immobilizing prey as they sink into the web due to gravity.

2.
Artigo em Inglês | MEDLINE | ID: mdl-32020504

RESUMO

Whether intra-myocardial delivery of hydrogel can prevent post-infarct heart failure (HF) in a long follow-up period, especially after it is degraded, remains unclear. In this study, Dex-PCL-HEMA/PNIPAAm (DPHP) hydrogel was delivered into peri-infarct myocardium of rat when coronary artery was ligated, while PBS was employed as control. Twelve weeks later, compared with control, left ventricle remodeling was attenuated and cardiac function was preserved; serum brain natriuretic peptide, cardiac aldosterone, and pulmonary congestion were suppressed in hydrogel group. Pro-fibrogenic mRNA increased in infarct area while decreased in remote zone, as well as hypertrophic mRNA. These data proves DPHP hydrogel suppresses ventricular remodeling and HF by promoting fibrotic healing in infarct area and inhibiting reactive fibrosis and hypertrophy in remote zone. Timely intra-myocardial hydrogel implantation is an effective strategy to inhibit post-infarct cardiac remodeling and have a long-term beneficial effect even after it has been biodegraded.

3.
Carbohydr Polym ; 233: 115818, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32059879

RESUMO

The binary nanocomposites blended by carboxymethyl cellulose (CMC) and SiO2 nanoparticles were constructed to prepare the films with superior thermal stability and flame retardant properties. The incorporation of cellulose nanofibers(CNFs) and SiO2 nanoparticles were followed to prepare ternary nanocomposite films exhibiting excellent mechanical properties. The mechanism and chemical reaction of the thermal decomposition for the CMC/SiO2 composite membrane were proposed, which showed that the mass residuals were Na2CO3, SiO2 and Na2SiO3, Na2CO3 when the content of the SiO2 nanoparticles was lowered and higher than 9.6 %, respectively. Compared with the pure CMC, micro combustion calorimeter (MCC) showed that the total heat release (THR) and the peak heat release rate (PHRR) both decreased from 6.4 kJ/g to 5.8 kJ/g, 134 w/g to 27 w/g, respectively. Moreover, mechanical properties of CMC/CNFs/SiO2 membrane showed that the toughness and rigidity of the nanocomposites increased by 56.0 % and 63.0 % on the basis of CMC, respectively.

5.
Bioorg Chem ; 94: 103356, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31785855

RESUMO

Indoleamine 2,3-dioxygenase 1 (IDO1) plays a vital role in tumor immune escape and has emerged as a promising target for cancer immunotherapy. In this study, a novel series of bicyclic carboxylic acid derivatives were designed, synthesized and evaluated for inhibitory activities against IDO1. Among these, compound 9c exhibited strong IDO1 inhibitory activity (HeLa cellular IC50 = 2.6 nM, THP-1 cellular IC50 = 11.2 nM). Further anti-tumor studies in vivo have shown that compound 9c has a great inhibitory effect on tumor growth in mice CT26 model as a single agent or in combination with 5-fluorouracil (inhibition rate was 53.9% and 92.7%, respectively). These results indicate that compound 9c is a effective IDO1 inhibitor for further investigation.

6.
Neurotox Res ; 37(2): 326-337, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31773641

RESUMO

Caffeic acid (CA) is a hydroxycinnamic acid derivative and polyphenol with antioxidant and anti-inflammatory activities. The neuroprotective properties of CA still need detailed characterization in different biological models. Here, the antioxidant and neuroprotective effects of CA were compared in in vitro and in vivo neurotoxic models. Biochemical outcomes of cell dysfunction, oxidative damage, and transcriptional regulation were assessed in rat cortical slices, whereas endpoints of physiological stress and motor alterations were characterized in Caenorhabditis elegans (C. elegans). In rat cortical slices, CA (100 µM) prevented, in a differential manner, the loss of reductive capacity, the cell damage, and the oxidative damage induced by the excitotoxin quinolinic acid (QUIN, 100 µM), the pro-oxidant ferrous sulfate (FeSO4, 25 µM), and the dopaminergic toxin 6-hydroxydopamine (6-OHDA, 100 µM). CA also restored the levels of nuclear factor erythroid 2-related factor 2/antioxidant response element (Nrf2/ARE; a master antioxidant regulatory pathway) binding activity affected by the three toxins. In wild-type (N2) of C. elegans, but not in the skn-1 KO mutant strain (worms lacking the orthologue of mammalian Nrf2), CA (25 mM) attenuated the loss of survival induced by QUIN (100 mM), FeSO4 (15 mM), and 6-OHDA (25 mM). Motor alterations induced by the three toxic models in N2 and skn-1 KO strains were prevented by CA in a differential manner. Our results suggest that (1) CA affords partial protection against different toxic insults in mammalian brain tissue and in C. elegans specimens; (2) the Nrf2/ARE binding activity participates in the protective mechanisms evoked by CA in the mammalian cortical tissue; (3) the presence of the orthologous skn-1 pathway is required in the worms for CA to exert protective effects; and (4) CA exerts antioxidant and neuroprotective effects through homologous mechanisms in different species.

7.
Bioorg Med Chem ; 28(1): 115228, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31813613

RESUMO

BRD4 has emerged as an attractive target for anticancer therapy. However, BRD4 inhibitors treatment leads to BRD4 protein accumulation, together with the reversible nature of inhibitors binding to BRD4, which may limit the efficacy of BRD4 inhibitors. To address these problems, a protein degradation strategy based on the proteolysis targeting chimera (PROTAC) technology has been developed to target BRD4 recently. Herein, we present our design, synthesis and biological evaluation of a new class of PROTAC BRD4 degraders, which were based on a potent dihydroquinazolinone-based BRD4 inhibitor compound 6 and lenalidomide/pomalidomide as ligand for E3 ligase cereblon. Gratifyingly, several compounds showed excellent inhibitory activity against BRD4, and high anti-proliferative potency against human monocyte lymphoma cell line THP-1. Especially, compound 21 (BRD4 BD1, IC50 = 41.8 nM) achieved a submicromolar IC50 value of 0.81 µM in inhibiting the growth of THP-1 cell line, and was 4 times more potent than compound 6. Moreover, the mechanism study established that 21 could effectively induce the degradation of BRD4 protein and suppression of c-Myc. All of these results suggested that 21 was an efficacious BRD4 degrader for further investigation.

8.
Mol Biol Rep ; 47(1): 201-209, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31612410

RESUMO

Circular RNA (circRNA), a novel type of non-coding RNA that consists of a circular loop, has been demonstrated to act as a "sponge" for microRNAs (miRNAs). However, the role of circRNAs in keloid remains unknown. In this study, we investigated circRNA expression profiles in keloid to identify potential diagnostic and therapeutic circRNAs. We performed a circRNA microarray assay to determine circRNA expression in keloid and paired normal skin tissues. Quantitative reverse transcription polymerase chain reaction was used to evaluate the expression levels of candidate circRNAs. The most significantly over-expressed circRNA was used to predict putative miRNA targets and the binding sites of miRNAs with this circRNA. Finally, we constructed a circRNA-miRNA interaction network and carried out gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses. We found 52 significantly upregulated and 24 downregulated circRNAs in keloid compared with normal skin tissue. We confirmed that hsa_circ_0057452, hsa_circ_0007482, hsa_circ_0020792, hsa_circ_0057342, and hsa_circ_0043688 were significantly upregulated in keloid tissues. Analysis of the circRNA-miRNA interaction network revealed that circRNAs could interact with miRNAs, including miRNA-29a, miRNA-23a-5p and miRNA-1976. GO and KEGG analyses indicated that these target genes were involved in biological functions and signaling pathways that may play vital roles in the pathogenesis of keloid. This study revealed that circRNAs are potentially implicated in the development of keloid and could serve as novel diagnostic and therapeutic targets.

9.
Gynecol Obstet Invest ; 85(1): 72-81, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31527378

RESUMO

BACKGROUND/AIMS: The identification of new compound candidates for endometriosis treatment is needed. Cyclooxygenase-2 (COX-2) is considered a crucial target to control the progress and recurrence of endometriosis. Here, we identified ursolic acid (UA) as a natural inhibitor of COX-2 and investigated its effects on endometriosis progression. METHODS: Primary human endometriotic stromal cells isolated from patients with endometriosis were exposed to UA at concentrations of 15, 30, 45, and 60 µM. 3-(4,5-Dimethylthiaziazol-2-yl)-2,5-diphenyl tetrazolium bromide assays, 5'-bromo-2'-deoxy-uridine assays, and Caspase-3 activity measurements were performed to detect cell growth and apoptosis. Enzyme-linked immunosorbent assays were used to detect COX-2 and vascular endothelial growth factor (VEGF) protein expression and prostaglandin E2 (PGE2) levels. Capillary-tubule formation assays using human umbilical vein endothelial cells were also carried out to determine angiogenesis. RESULTS: UA significantly decreased cell viability, inhibited proliferation, and increased caspase-3 activity in a dose-dependent manner. COX-2 protein expression and the subsequent PGE2 production were both reduced by UA. Meanwhile, UA exposure decreased VEGF secretion in the stromal cells and the capillary-tubule formation assay confirmed the inhibitory effect of UA on angiogenesis. Furthermore, UA increased the phosphorylation of c-Jun N-terminal kinase and p38. CONCLUSIONS: Our data suggest that UA plays a role as a natural inhibitor of COX-2 to control the survival of human endometriotic stromal cells by inhibiting proliferation and angiogenesis and promoting apoptosis.

10.
Chemosphere ; 242: 125178, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31675587

RESUMO

The comprehensive recovery of iron and titanium resources from early tailings were systematically attempted from fundamental work to industrial application. Geochemical characterization of the tailings was first conducted, followed by the iron recovery and titanium recovery. Iron recovery was mainly achieved through a series of magnetic separation, and titanium recovery was on the combination of magnetic pre-concentration and flotation separation. Special for titanium recovery, different pretreatment methods including ultrasonic cleaning and attrition-scrubbing were studied to reduce the influence of serious surface pollution of early tailings on ilmenite floatability, and attrition-scrubbing proved to be the best one. Associated mechanisms of flocculants influence on ilmenite floatability and the attrition-scrubbing effects were explored using micro-flotation and XPS tests. After a series of fundamental studies, the industrial production of iron and ilmenite concentrate went into operation and the industrial debugging results were roughly satisfactory. At last, a brief economic analysis was given for the present work.

11.
Carbohydr Polym ; 229: 115395, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31826411

RESUMO

Oxygen protection/isolation is imperative to prevent the lipid oxidation since oxygen molecule is an ultimate quencher in photon conversion process. Inspired by the structural buildup of seeds from oil crops, a sustainable solid particle stabilizer with novel antioxidant activity was prepared by using cellulose and polyphenol. In this work, bacterial cellulose (BC) nanofibrils modified by tea polyphenols (TPs) was prepared and used as Pickering emulsifier for the O/W emulsion. BC nanofibirls exhibited excellent adsorption capacity up to 55 µg/mg, and the adsorption kinetics between BC and TPs were further investigated. After modification, the interfacial diffusion rate constant of BC was significantly increased to from 0.43 to 1.21 mN m-1 s-0.5. Moreover, the obtained O/W interfacial modulus of the dilatational elasticity was increased from 58 to 130 mN/m. Furthermore, the emulsions exhibited excellent free-radical scavenging activity at oil-water interface, suggesting a potential application in usage to extend the lifespan of the food containing polyunsaturated fats.

12.
Biomed Pharmacother ; 123: 109802, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31884339

RESUMO

BACKGROUND: Acute myeloid leukemia (AML) is a common hematopoietic malignancy with invasive activity. Drug resistance greatly contributes to the poor efficacy of chemotherapy in AML treatment. Recent research indicates that long non-coding RNAs (LncRNAs) regulates chemotherapy resistance in malignancy. METHODS: Microarray analysis was used to screen out AML related genes, and interaction between small nucleolar RNA host gene 5(SNHG5) and miR-32, as well as that between miR-32 and DNAJB9. Quantitative real-time PCR (qRT-PCR) and In situ hybridization(ISH) were used to determine the expression levels of SNHG5, miR-32 and DNAJB9 mRNA in AML cell lines and clinic samples. Western blot was performed to detect protein expression levels. After being treated with varying concentrations of Adriamycin(ADM), cell viability was evaluated using a cell counting kit-8(CCK8). RESULTS: We carried out a genome-wide LncRNA expression study and found SNHG5 aberrantly overexpressed in AML comparing to the donors. Knock-down of SNHG5 promoted sensitivity of AML cells to chemotherapy. In addition, miR-32 was identified as the downstream target of SNHG5 and miR-32 inhibitor abrogated the inhibiting effects of downregulated SNHG5 on AML cell viability. Furthermore, inhibited SNHG5 decreased DNAJB9 expression levels by sponging miR-32. The SNHG5/miR-32/DNAJB9 axis targeted autophagy to regulate chemotherapy resistance. CONCLUSION: SHNG5 regulates chemotherapy resistance by targeting the miR-32/DNAJB9 axis in acute myeloid leukemia, which provided a novel potential target for AML and revealed an important mechanism of chemotherapy resistance.

13.
Zhong Nan Da Xue Xue Bao Yi Xue Ban ; 44(10): 1157-1162, 2019 Oct 28.
Artigo em Chinês | MEDLINE | ID: mdl-31857510

RESUMO

OBJECTIVE: To investigate the clinical characteristics of dermatomyositis, to investigate the types and clinical features of dermatomyositis complicated with malignant tumor, and to provide evidence for clinical diagnosis, treatment and prognostic evaluation.
 Methods: The clinical manifestations and laboratory test results for 108 cases of dermatomyositis with complications in the Second Xiangya Hospital of Central South University were analyzed.
 Results: Patients aged from 14 to 60 years accounted for 62.96%. The first symptom was single skin rash (54.63%), and the most characteristic cutaneous features were asymmetrical proximal myositis with various degrees (97.22%). The visceral involvement was as follows: the digestive tract (31.48%), the heart (19.44%), the lung (26.85%), and the thyroid damage (12.96%). Twelve (11.11%) patients were combined with malignant tumor. The positive rates for albumin (ALB), glutamic oxalacetic transaminase (AST), glutamic-pyruvic transaminase (ALT), lactate dehydrogenase (LDH), creatine kinase (CK), creatine kinase isoenzyme (CK-MB), erythrocyte sedimentation rate (ESR), anti Jo-1 antibody, anti ribonucleoprotein (RNP) antibody, and anti-topoisomerasel (Scl) antibody were 25.93%, 46.30%, 28.70%, 87.04%%, 51.85%, 26.85%, 55.56%, 2.27%, 8.99%, and 2.27%, respectively. The patients were divided into a tumor group and a non-tumor group. The chi-square test results from clinical symptoms and laboratory tests suggested that increase of ESR was a risk factor for dermatomyositis combining tumor. The main strategy of therapy was corticosteroids.
 Conclusion: Dermatomyositis possesses typical skin lesions and dermatitis is the most common initial symptom of dermatomyositis. In clinic, diagnosis of dermatomyositis should be timely combined with muscle enzymes test, electromyography and muscle biopsy. Dermatomyositis can easily involve many organs. Thus relevant examinations (such as chest X-ray and CT) should be done preventively. Rapid ESR is a risk factor for dermatomyositis complicated with malignant tumor and it can be used as an index to guide clinical diagnosis.


Assuntos
Dermatomiosite , Adolescente , Adulto , Creatina Quinase , Eletromiografia , Humanos , Pessoa de Meia-Idade , Pele , Adulto Jovem
14.
J Org Chem ; 2019 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-31840511

RESUMO

The application of amine derivatives as coupling partners is rare due to the inherent strength of the C-N bond. Herein, we report the first cross-electrophile coupling reaction of unstrained benzylic sulfonamides. Nickel-catalyzed intramolecular cross-electrophile coupling reactions of acyclic and cyclic benzylic sulfonamides with pendant alkyl chlorides generate cyclopropane products. Mechanistic experiments and DFT calculations are consistent with initiation of the reaction by magnesium iodide accelerated oxidative addition of the benzylic sulfonamide. This work establishes neutral and unstrained amine derivatives as XEC partners, furnishes structural rearrangement of benzylic sulfonamides, and provides valuable information regarding catalyst design for the development of new cross-electrophile coupling reactions of carbon-heteroatom bonds.

15.
Zhongguo Zhong Yao Za Zhi ; 44(20): 4426-4432, 2019 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-31872628

RESUMO

The objectives of study were to explore the effects of exogenous methyltestosterone( MT) on the growth and gonadal development of overwintering Whitmania pigra. Before overwintering,0. 1,1. 0,10. 0,100. 0,150. 0 µg·L-1 of MT were added to the aquaculture water for 6 weeks. The changes of growth performance,gonad index,endogenous steroid hormones level and internal quality were measured after hibernate for 60 days. Then the tissue slice technique was used to observe the spermary( ovary) of Wh. pigra.The results showed that the body weight,survival rate and gonadal index increased first and then decreased with the increase of exogenous MT concentration; the male gland index was found the highest at the concentration of MT 10. 0 µg·L-1 and the female gland index was the highest at the concentration of MT 1. 0 µg·L-1. The survival rate of Wh. pigra peaked at the concentration of MT 10. 0 µg·L-1.The weight reaches a peak at a concentration of MT 100. 0 µg·L-1( P<0. 05). The number of primary spermatocytes in the testis was negatively correlated with the concentration of exogenous MT. The number of secondary spermatocytes and sperm cells increased first and then decreased. The concentration of secondary spermatocytes was the highest when the concentration of MT was 100. 0 µg·L-1.The number and volume of oocytes in the ovary and the yolk granules increased first and then decreased with the increase of exogenous MT concentration,and the highest was observed at the MT concentration of 100. 0 µg·L-1. The endogenous steroid hormone of Wh.pigra increased first and then decreased with the increase of exogenous MT concentration. The concentration of androgen and progesterone was the highest in MT 100. 0 µg·L-1 treatment( P<0. 05),and the concentration of estrogen was found the highest in MT 10. 0 µg·L-1 treatment( P<0. 05). After adding exogenous MT,Wh. pigra moisture content,acid-insoluble ash content,p H and anti-thrombin activity met the quality criterion of medicinal Wh. pigra in Chinese Pharmacopoeia( 2015 edition). In conclusion,the short-term addition of 1. 0-100. 0 µg·L-1 exogenous MT before hibernation can promote the growth,the development of sperm cells and the antithrombin activity of Wh. pigra.


Assuntos
Sanguessugas/fisiologia , Metiltestosterona , Animais , Estrogênios , Feminino , Gônadas , Masculino , Ovário , Progesterona
16.
Onco Targets Ther ; 12: 8833-8840, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31695438

RESUMO

Aim: To examine the prognostic values of circulating tumor cells (CTCs) in patients with advanced lung cancer. Patients and methods: A total of 98 patients with their CTCs enumerated in 2017 was recruited. Data were retrieved from medical records for comparison. Patients' overall survival (OS) and progression-free survival (PFS) were studied using Kaplan-Meier curve with log rank test. Results: Seventy-three percent of the patients were male, and nearly half of the patients (44.8%) were smokers. Most tumors were adenocarcinoma (73.4%), and about 60% of the cases were diagnosed at stage IV. Half of the patients showing less than nine CTCs. Patients' OS were significantly associated with total CTC count (P=0.047), epithelial CTC count (P=0.027), mixed CTC count (P=0.004), and use of adjuvant chemotherapy (P=0.001). For PFS, it was strongly associated with tumor backgrounds (T stage, P=0.002; M stage, P=0.001; TMN stage, P<0.001), cancer biomarkers (CEA, P=0.004; CA125, P=0.004; CA153, P=0.045), and treatment strategy (surgical intervention, P=0.025; first-line chemotherapy, P<0.001). Conclusion: The present study clearly indicated the significant associations between CTC and overall survival of patients with lung cancer.

17.
Sci Adv ; 5(11): eaav4355, 2019 11.
Artigo em Inglês | MEDLINE | ID: mdl-31700996

RESUMO

Recently, several captivating topological structures of electric dipole moments (e.g., vortex, flux closure) have been reported in ferroelectrics with reduced size/dimensions. However, accurate polarization distribution of these topological ferroelectric structures has never been experimentally obtained. We precisely measure the polarization distribution of an individual ferroelectric vortex in PbTiO3/SrTiO3 superlattices at the subunit cell level by using the atomically resolved integrated differential phase contrast imaging in an aberration-corrected scanning transmission electron microscope. We find, in vortices, that out-of-plane polarization is larger than in-plane polarization, and that downward polarization is larger than upward polarization. The polarization magnitude is closely related to tetragonality. Moreover, the contribution of the Pb─O bond to total polarization is highly inhomogeneous in vortices. Our precise measurement at the subunit cell scale provides a sound foundation for mechanistic understanding of the structure and properties of a ferroelectric vortex and lattice-charge coupling phenomena in these topological ferroelectric structures.

18.
Ultramicroscopy ; 209: 112885, 2019 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-31722280

RESUMO

Long-period patterns (LPPs) are widely observed by transmission electron microscopy (TEM) in the study of nanoscale materials. Identifying the origin of LPPs is of significant importance when interpreting TEM images, and for an in-depth understanding of material characteristics. However, the two most common LPP categories, modulated structure and moiré patterns, are not easily differentiated by conventional TEM (CTEM). In this work, an LPP was observed in Cu2-xSe nanoplates by CTEM. And then the depth sectioning with an aberration-corrected scanning transmission electron microscope (AC STEM) has been performed to determine the LPP type. Two misorientated layers were recognized from the depth-series of atomic resolution images of an LPP region, confirming the LPP is a moiré pattern caused by two twisted stacked crystal flakes which commonly exists in nanosized materials. This depth sectioning method is generally applicable for structural characterization of layered systems, and is a powerful approach for the in-situ structural probe of nanomaterials. It is promising to be extended to fast three-dimensional (3D) reconstruction.

19.
Reprod Biol Endocrinol ; 17(1): 89, 2019 11 06.
Artigo em Inglês | MEDLINE | ID: mdl-31690315

RESUMO

The authors regret that the incorrect identification of "omega-3 arachidonic acid" published in the original manuscript [1].

20.
J Cell Biol ; 218(12): 4063-4078, 2019 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-31636119

RESUMO

How nuclear size is regulated relative to cell size is a fundamental cell biological question. Reductions in both cell and nuclear sizes during Xenopus laevis embryogenesis provide a robust scaling system to study mechanisms of nuclear size regulation. To test if the volume of embryonic cytoplasm is limiting for nuclear growth, we encapsulated gastrula-stage embryonic cytoplasm and nuclei in droplets of defined volume using microfluidics. Nuclei grew and reached new steady-state sizes as a function of cytoplasmic volume, supporting a limiting component mechanism of nuclear size control. Through biochemical fractionation, we identified the histone chaperone nucleoplasmin (Npm2) as a putative nuclear size effector. Cellular amounts of Npm2 decrease over development, and nuclear size was sensitive to Npm2 levels both in vitro and in vivo, affecting nuclear histone levels and chromatin organization. We propose that reductions in cell volume and the amounts of limiting components, such as Npm2, contribute to developmental nuclear size scaling.

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