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1.
J Invertebr Pathol ; 177: 107481, 2020 Oct 06.
Artigo em Inglês | MEDLINE | ID: mdl-33035534

RESUMO

Ticks are considered to be the second most important vectors of human infectious diseases. The innate immune system is the key factor that affects its vector competence. Hyalomma asiaticum is the primary vector of Crimean-Congo hemorrhagic fever virus (CCHFV). However, the immune system of H. asiaticum remains virtually unknown. Here, a high throughput full-length mRNA sequencing method was adopted to define the immunotranscriptome of H. asiaticum infected with the fungal pathogen Beauveria bassiana and gram-negative bacterium Enterobacter cloacae. The analysis yielded 22,300 isoforms with an average length of 3233 bps. In total, 68 potential immunity-related genes were identified based on similarity to the homologs known to be involved in immunity. These included most members of the Toll and JAK/STAT signaling pathways, but not the IMD signaling pathway. Moreover, two copies of Dicer-2 and five copies of Argonaute-2 were detected. These genes are postulated to be involved in the RNA interference (RNAi) pathway, which is an important defense against RNA viruses. Overall, this study provides the foundation for understanding the immune response of H. asiaticum to CCHFV.

2.
Nanoscale ; 2020 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-33079119

RESUMO

The gut microbiome can be readily influenced by external factors, such as nanomaterials. However, the role of the microbiota-gut-brain axis in nanomaterials-induced neurotoxicity remains largely unknown. In this study, young mice aged 4 weeks were treated with either a vehicle solution or 26 mg kg-1 zinc oxide nanoparticles (ZnONPs) by intragastric administration for 30 days. The neurobehavioral alterations were assessed by the Morris water maze and open field test. Gut microbiota and the metabolites in both blood and hippocampus were detected using 16S rRNA sequencing and liquid chromatography-mass spectrometry metabolomics, respectively. The results demonstrated that oral exposure to ZnONPs resulted in neurobehavioral impairments in young mice, mainly manifested by spatial learning and memory deficits, and the inhibition of locomotor activity. Intriguingly, ZnONPs caused a marked disturbance of the gut microbial composition, but did not alter the α-diversity of the microbiota. The correlation analysis further revealed that neurobehavioral impairments induced by ZnONPs were closely associated with a perturbation in the gut microbiota composition that were specific to changes of neurobehavior-related genes (such as Bdnf and Dlg4), and correlated with serum and hippocampal metabolites. We also identified a unique metabolite [DG(15:0/0:0/22:4n6)] that linked relationships among the gut microbiota, metabolites and neurobehavior-related genes. Taken together, our results illustrated that oral exposure to ZnONPs not only altered the gut microbiome community, but also substantially disturbed the metabolic profiles leading to neurobehavioral impairments via the microbiota-gut-brain axis. These findings will provide a novel view for understanding the neurotoxicity of ZnONPs, and are helpful for identifying potential prevention and treatment strategies.

3.
Int J Nanomedicine ; 15: 5299-5315, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32884256

RESUMO

Purpose: Zinc oxide nanoparticles (ZnONPs) are one of the most important nanomaterials that are widely used in the food, cosmetic and medical industries. Humans are often exposed to ZnONPs via inhalation, and they may reach the brain where neurotoxic effects could occur via systemic distribution. However, the mechanisms underlying how ZnONPs produce neurotoxic effects in the brain remain unclear. In this study, we aimed to investigate the novel mechanism involved in ZnONPs-induced neurotoxicity. Methods and Results: We demonstrated for the first time that pulmonary exposure to ZnONPs by intratracheal instillation could trigger ferroptosis, a new form of cell death, in the neuronal cells of mouse cerebral cortex. A similar phenomenon was also observed in cultured neuron-like PC-12 cell line. By using a specific inhibitor of ferroptosis ferrostatin-1 (Fer-1), our results showed that inhibition of ferroptosis by Fer-1 could significantly alleviate the ZnONPs-induced neuronal cell death both in vivo and in vitro. Mechanistic investigation revealed that ZnONPs selectively activated the JNK pathway and thus resulted in the ferroptotic phenotypes, JNK inhibitor SP600125 could reverse lipid peroxidation upregulation and ferroptotic cell death induced by ZnONPs in PC-12 cells. Conclusion: Taken together, this study not only demonstrates that pulmonary exposure of ZnONPs can induce JNK-involved ferroptotic cell death in mouse cortex and PC-12 cells, but also provides a clue that inhibition of ferroptosis by specific agents or drugs may serve as a feasible approach for reducing the untreatable neurotoxicity induced by ZnONPs.

4.
Proc Natl Acad Sci U S A ; 117(38): 23581-23587, 2020 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-32900946

RESUMO

Proteolytic activation of phenoloxidase (PO) and the cytokine Spätzle during immune responses of insects is mediated by a network of hemolymph serine proteases (HPs) and noncatalytic serine protease homologs (SPHs) and inhibited by serpins. However, integration and conservation of the system and its control mechanisms are not fully understood. Here we present biochemical evidence that PO-catalyzed melanin formation, Spätzle-triggered Toll activation, and induced synthesis of antimicrobial peptides are stimulated via hemolymph (serine) protease 5 (HP5) in Manduca sexta Previous studies have demonstrated a protease cascade pathway in which HP14 activates proHP21; HP21 activates proPAP2 and proPAP3, which then activate proPO in the presence of a complex of SPH1 and SPH2. We found that both HP21 and PAP3 activate proHP5 by cleavage at ESDR176*IIGG. HP5 then cleaves proHP6 at a unique site of LDLH112*ILGG. HP6, an ortholog of Drosophila Persephone, activates both proHP8 and proPAP1. HP8 activates proSpätzle-1, whereas PAP1 cleaves and activates proPO. HP5 is inhibited by Manduca sexta serpin-4, serpin-1A, and serpin-1J to regulate its activity. In summary, we have elucidated the physiological roles of HP5, a CLIPB with unique cleavage specificity (cutting after His) that coordinates immune responses in the caterpillar.

5.
Phytochemistry ; 180: 112514, 2020 Sep 17.
Artigo em Inglês | MEDLINE | ID: mdl-32950771

RESUMO

Seven undescribed C27 steroidal glycosides, Seladelicatulasine A-G, including six cholestanol glycosides and one spirostanol glycoside, were isolated from Selaginella delicatula. Their structures were elucidated by 1D/2D NMR spectra and HRESIMS analyses. The absolute configurations of the sugars were determined by enzymatic hydrolysis and GC/MS analyses. These cholestanol glycosides were isolated from the family Selaginellaceae for the first time. Seladelicatulasine F is characterized as a rare B-5,6-secosteroid. In addition, all the compounds were evaluated for their inhibitory activities against cholinesterase (AChE/BChE) and monoamine oxidase (MAO-A/MAO-B). These steroidal glycosides displayed selective inhibition activities on cholinesterase. Seladelicatulasine A, B and E inhibited the AChE activity with IC50 values of 0.31, 0.09, and 0.04 µM, respectively. Seladelicatulasine A and F showed the strongest inhibition activity on BChE with IC50 values of 0.37 and 0.65 µM, respectively.

6.
Cell Prolif ; : e12904, 2020 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-32997394

RESUMO

OBJECTIVES: Most bone fracture heals through enchondral bone formation that relies on the involvement of periosteal progenitor cells. However, the identity of periosteal progenitor cells and the regulatory mechanism of their proliferation and differentiation remain unclear. The aim of this study was to investigate whether Gli1-CreERT2 can identify a population of murine periosteal progenitor cells and the role of TGF-ß signalling in periosteal progenitor cells on fracture healing. MATERIALS AND METHODS: Double heterozygous Gli1-CreERT2 ;Rosa26-tdTomatoflox/wt mice were sacrificed at different time points for tracing the fate of Gli1+ cells in both intact and fracture bone. Gli1-CreERT2 -mediated Tgfbr2 knockout (Gli1-CreERT2 ;Tgfbr2flox/flox ) mice were subjected to fracture surgery. At 4, 7, 10, 14 and 21 days post-surgery, tibia samples were harvested for tissue analyses including µCT, histology, real-time PCR and immunofluorescence staining. RESULTS: Through cell lineage-tracing experiments, we have revealed that Gli1-CreER T2 can be used to identify a subpopulation of periosteal progenitor cells in vivo that persistently reside in periosteum and contribute to osteochondral elements during fracture repair. During the healing process, TGF-ß signalling is continually activated in the reparative Gli1+ periosteal cells. Conditional knockout of Tgfbr2 in these cells leads to a delayed and impaired enchondral bone formation, at least partially due to the reduced proliferation and chondrogenic and osteogenic differentiation of Gli1+ periosteal cells. CONCLUSIONS: TGF-ß signalling plays an essential role on fracture repair via regulating enchondral bone formation process of Gli1+ periosteal cells.

7.
J Hazard Mater ; 398: 122748, 2020 11 05.
Artigo em Inglês | MEDLINE | ID: mdl-32768853

RESUMO

Gut microbiota is intimately involved in numerous aspects of human health. Arsenite expouse can perturb gut microbiota and is linked to increased susceptibility of individual to arsenite-related diseases. However, how microbiome factors influence arsenite-induced neurotoxicity remains largely unknown. In this study, after treating of healthy adult female mice with arsenite via drinking water for 6 months, our results clearly revealed that chronic arsenite exposure not only perturbed the composition of gut microbiota but also caused neurobehavioral dysfunctions, which manifested by learning and memory deficits and anxiety-like behavior. Given that the overactive autophagy directly leads to gut pathological changes, we further assessed whether inhibiton of autophagy by genetic mean could reverse arsenite-induced neurobehavioral dysfunctions. Our results illustrated for the first time that heterozygous disruption of beclin 1, which played a central role in autophagy, alleviated the perturbation of gut microbiome phenotypes induced by arsenite, and ultimately leading to the improvement of neurobehavioral deficits through gut-brain communication. These findings provide a new clue that regulation of autophagy is a potential approach for probing the functional impacts of arsenite on the gut microbiome, and it also may be severed as a way for protection strategies against arsenite neurotoxicity.

8.
Platelets ; : 1-10, 2020 Aug 24.
Artigo em Inglês | MEDLINE | ID: mdl-32835568

RESUMO

Steroid-associated necrosis of the femoral head (SANFH) is one of the most common and refractory chronic diseases with increasing incidence. The typical pathological changes of SANFH include decreased osteogenic differentiation, enhanced intramedullary adipocytes deposition and impaired osseous circulation. In this study, we investigated the effects and potential mechanisms of Platelet-rich plasma (PRP) on SANFH. Sixty Sprague-Dawley rats were randomly divided into the control, PRP donor, model, and PRP groups. Compared to the model group, PRP treatment significantly increased the hemorheological indexes and serum levels of bone gla-protein (BGP) and vascular endothelial growth factor (VEGF), while decreased the levels of triglyceride (TG) and total cholesterol (TC). Meanwhile, Micro-CT and histopathological stain (Hematoxylin-eosin and Alcian blue-hematoxylin/orange G staining) were performed on the femoral head for morphological and histopathological evaluation, indicating that bone trabecular microstructure and bone mineral density (BMD) were significantly improved after PRP treatment. Immunohistochemical analysis revealed that PRP remarkably up-regulated the expression of osteogenic markers including ß-catenin and alkaline phosphatase (ALP), angiogenic markers containing VEGF and platelet endothelial cell adhesion molecule-1 (CD31), while down-regulated adipogenic markers involving fatty acid-binding protein (FABP-4), and peroxisome proliferator-activated receptor gamma (PPAR-γ) in SANFH rat models. In summary, for the first time, PRP was demonstrated to prevent the development of SANFH through stimulating bone formation and vascularization as well as retarding adipogenesis.

9.
Mikrochim Acta ; 187(9): 497, 2020 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-32803418

RESUMO

For the first time it is demonstrated that sulfhydryl compounds can suppress longitudinal etching of gold nanorods via consuming oxidizers, which provides a new signaling mechanism for colorimetric sensing. As a proof of concept, a colorimetric assay is developed for detecting organophosphorus pesticides, which are most widely used in modern agriculture to improve food production but with high toxicity to animals and the ecological environment. Triazophos was selected as a model organophosphorus pesticide. In the absence of triazophos, the active acetylcholinesterase can catalyze the conversion of acetylthiocholine iodide to thiocholine whose thiol group can suppress the I2-induced etching of gold nanorods. When triazophos is present, the activity of AchE is inhibited, and I2-induced etching of gold nanorods results in triazophos concentration-dependent color change from brown to blue, pink, and red. The aspect ratio of gold nanorods reduced with gradually blue-shifted longitudinal absorption. There was a linear detection range from 0 to 117 nM (R2 = 0.9908), the detection limit was 4.69 nM, and a good application potential was demonstrated by the assay of real water samples. This method will not only contribute to public monitoring of organophosphorus pesticides but also has verified a new signaling mechanism which will open up a new path to develop colorimetric detection methods. It has been first found that sulfhydryl compounds can suppress longitudinal etching of gold nanorods (AuNRs) via consuming oxidizers, which provides a new signaling mechanism for colorimetric sensing. As a proof of concept, a colorimetric assay is developed for sensitively detecting organophosphorus pesticides (OPs). It will not only contribute to public monitoring of OPs but also has verified a new signaling mechanism which will open up a new path to develop multicolor colorimetric methods.

10.
ACS Synth Biol ; 9(9): 2440-2449, 2020 09 18.
Artigo em Inglês | MEDLINE | ID: mdl-32794765

RESUMO

DNA writing (living sensing recorders) based whole-cell biosensors can capture transient signals and then convert them into readable genomic DNA changes. The primitive signals can be easily obtained by sequencing technology or analysis of protein activity (such as fluorescent protein). However, the functions of the current living sensing recorders still need to be expanded, and the difficulty of rewriting in complex biological environments has further limited their applications. In this study, we designed a long-term rewritable recording system using a CRISPR base editor-based synthetic genetic circuit, named CRISPR-istop. This system can convert stimuli into changes in the fluorescence intensity (reporter) and single-base mutations in genomic DNA (recording). Furthermore, we updated the biological circuit through the strategy of coupling the single-base mutation (record site) and the loss-of-function of the targeted protein (translation stopped by stop codon introduction), and we can remove edited bacteria from a population through selective sweeps upon applying a selective pressure. It successfully conducted the rewritable reporter and recording of the nutrient arabinose and pollutant arsenite with two rounds of continuous operation (10 passages/round, 12 h/passage). These observations indicated that the CRISPR-istop system can report and record stimuli over time; moreover, the recording can be manually erased and rewritten as needed. This method has great potential to be extended to more complicated recording systems to execute sophisticated tasks in inaccessible environments for synthetic biology and biomedical applications, such as monitoring disease-relevant physiological markers or other molecules.

11.
Neurotoxicology ; 81: 40-50, 2020 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-32783905

RESUMO

Increasing occupational and accidental exposure to carbon black nanoparticles (CBNPs) raise concerns over their possible effects on the nervous system. However, the influences of CBNPs on the neurodevelopment remain unclear. Thus, in this study, pregnant mice were exposed to different doses of CBNPs by intranasal instillation on gestation days 9-18. Our results demonstrated that maternal exposure to CBNPs caused significant changes on maternal behaviors. Pregnancy exposure to CBNPs also delayed the onset of incisor eruption, testes descent and vaginal opening in offspring, and caused the reduced body weight until adulthood. In the neurobehavioral tests, CBNPs-exposed offspring exhibited the elevated latency of negative geotaxis and surface right reflex, reduced grasping time and increased cliff avoidance. Histopathological changes were present in F1 generation but not in F2 generation. Intriguingly, our data revealed that the levels of total m6A modification were significantly decreased by CBNPs. Similar trends were observed on the mRNA expressions of m6A methyltransferases and demethylases. In summary, these findings provide the novel evidence that pregnancy exposure to CBNPs affects the maternal behaviors and partially induces the neurobehavioral, muscular and histopathological changes in offspring. Of note, these adverse effects may be associated with reduced levels of total m6A modification in brain.

12.
Cancer Manag Res ; 12: 6563-6573, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32801894

RESUMO

Background: Non-small cell lung carcinoma (NSCLC) is often fatal; advanced NSCLC has a 5-year survival rate less than 20%. Platinum-based chemotherapy, in particular, cis-diamminedichloroplatinum (II) (cisplatin or DDP), is employed for the treatment of NSCLC; however, the drug resistance occurs frequently. Autophagy is defined as the process of intracellular degradation of cytoplasmic materials in the lysosome; however, the correlation between autophagy and drug resistance remains controversial. Herein, we investigated the correlation between autophagy and cisplatin resistance and also explored the underlying mechanisms. Methods and Results: We demonstrated that DDP-resistant NSCLC A549 (A549/DDP) cells had higher autophagy activity in comparison with its parental A549 cells; DDP treatment induced a time- and dose-dependent decrease of autophagy. Intriguingly, inhibition of autophagy with pharmacological drugs or knockdown of ATG5 or Beclin-1 aggravated cell death induced by DDP treatment, indicating that autophagy played protective roles during DDP treatment. Further mechanistic investigation revealed that DDP treatment could decrease the mRNA expression level of key autophagy-related genes, such as ATG5, Beclin-1, and ATG7, suggesting DDP repressed autophagy at the transcriptional level. The MiTF/TFE family (including TFEB, TFE3, TFEC, and MiTF) were involved in nutrient sensing and organelle biogenesis, and specifically, the lysosomal biogenesis. We found that only MiTF was dramatically decreased upon DDP treatment, and also a profound decrease of lysosomal markers, LAMP-1 or LAMP-2, suggesting that MiTF was involved in the modulation of lysosomal biogenesis and, consequently, the autophagy. Moreover, the knockdown of MiTF resulted in more severe cell death in A549/DDP cells, indicting the substantial correlation between MiTF and cisplatin chemoresistance. Conclusion: Our study provides novel insights into the association between MiTF and DDP chemoresistance in NSCLC cells, and suggests targeting MiTF and/or autophagy might be a potential strategy for the reversal of DDP chemoresistance for NSCLC treatment.

13.
J Asian Nat Prod Res ; : 1-7, 2020 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-32608251

RESUMO

One new pentacyclic triterpenoid, urs-12,16-dien-3-one (1), together with twelve known pentacyclic triterpenoids (2‒13), were isolated from the twigs and leaves of Melaleuca linariifolia. Their structures were characterized by their 1D- and 2 D-NMR spectra analysis and mass spectra studies. Furthermore, all isolated compounds were tested the inhibitory effect on proliferation of six human cancer cell lines in vitro, including NCI-H441, NCI-H460, A549, SKOV3, hela, and caki-1 cells. Among them, compounds 3, 5, 7, 9, 12, and 13 exhibited moderate antiproliferative activities with IC50 values ranging from 3.85 to 33.31 µM.

14.
Int J Nanomedicine ; 15: 3291-3302, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32494130

RESUMO

Background: Inhaled nanoparticles can cross pulmonary air-blood barrier into circulation and cause vascular endothelial injury and progression of cardiovascular disease. However, the molecular mechanism underlying the vascular toxicity of copper oxide nanoparticles (CuONPs) remains unclear. We have recently demonstrated that the release of copper ions and the accumulation of superoxide anions contributed to CuONPs-induced cell death in human umbilical vein endothelial cells (HUVECs). Herein, we further demonstrate the mechanism underlying copper ions-induced cell death in HUVECs. Methods and Results: CuONPs were suspended in culture medium and vigorously vortexed for several seconds before exposure. After treatment with CuONPs, HUVECs were collected, and cell function assays were conducted to elucidate cellular processes including cell viability, oxidative stress, DNA damage and cell signaling pathways. We demonstrated that CuONPs uptake induced DNA damage in HUVECs as evidenced by γH2AX foci formation and increased phosphorylation levels of ATR, ATM, p53 and H2AX. Meanwhile, we showed that CuONPs exposure induced oxidative stress, indicated by the increase of cellular levels of superoxide anions, the upregulation of protein levels of heme oxygenase-1 (HO-1) and glutamate-cysteine ligase modifier subunit (GCLM), the elevation of the levels of malondialdehyde (MDA), but the reduction of glutathione to glutathione disulfide ratio. We also found that antioxidant N-acetyl-L-cysteine (NAC) could ameliorate CuONPs-induced oxidative stress and cell death. Interestingly, we demonstrated that p38 mitogen-activated protein kinase (MAPK) signaling pathway was activated in CuONPs-treated HUVECs, while p38α MAPK knockdown by siRNA significantly rescued HUVECs from CuONPs-induced DNA damage and cell death. Importantly, we showed that copper ions chelator tetrathiomolybdate (TTM) could alleviate CuONPs-induced oxidative stress, DNA damage, p38 MAPK pathway activation and cell death in HUVECs. Conclusion: We demonstrated that CuONPs induced oxidative DNA damage and cell death via copper ions-mediated p38 MAPK activation in HUVECs, suggesting that the release of copper ions was the upstream activator for CuONPs-induced vascular endothelial toxicity, and the copper ions chelator TTM can alleviate CuONPs-associated cardiovascular disease.


Assuntos
Cobre/toxicidade , Dano ao DNA , Células Endoteliais da Veia Umbilical Humana/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/patologia , Nanopartículas/toxicidade , Estresse Oxidativo/efeitos dos fármacos , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Morte Celular/efeitos dos fármacos , Ativação Enzimática/efeitos dos fármacos , Células Endoteliais da Veia Umbilical Humana/metabolismo , Humanos , Modelos Biológicos , Molibdênio/química , Nanopartículas/ultraestrutura
15.
Phytomedicine ; 76: 153256, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32534359

RESUMO

BACKGROUND: Although Bushenhuoxue formula (BSHXF) is successfully used as a non-traumatic therapy in treating bone fracture in China, the molecular mechanism underlying its effects remains poorly understood. PURPOSE: The present study aims to explore the therapeutic effects of BSHXF on fracture healing in mice and the underlying mechanism. METHODS: We performed unilateral open transverse tibial fracture procedure in C57BL/6 mice which were treated with or without BSHXF. Fracture callus tissues were collected and analyzed by X-ray, micro-CT, biomechanical testing, histopathology and quantitative gene expression analysis. Tibial fracture procedure was also performed in Cre-negative and Gli1-CreER; Tgfbr2flox/flox conditional knockout (KO) mice (Tgfbr2Gli1ER) to determine if BSHXF enhances fracture healing in a TGF-ß-dependent manner. In addition, scratch-wound assay and cell counting kit-8 (CCK-8) assay were used to evaluate the effect of BSHXF on cell migration and cell proliferation in C3H10T1/2 mesenchymal stem cells, respectively. RESULTS: BSHXF promoted endochondral ossification and enhanced bone strength in wild-type (WT) or Cre- control mice. In contrast, BSHXF failed to promote bone fracture healing in Tgfbr2Gli1ER conditional KO mice. In the mice receiving BSHXF treatment, TGF-ß/Smad2 signaling was significantly activated. Moreover, BSHXF enhanced cell migration and cell proliferation in C3H10T1/2 cells, which was strongly attenuated by the small molecule inhibitor SB525334 against TGF-ß type I receptor. CONCLUSION: These data demonstrated that BSHXF promotes fracture healing by activating TGF-ß/Smad2 signaling. BSHXF may be used as a type of alternative medicine for the treatment of bone fracture healing.

16.
Angew Chem Int Ed Engl ; 59(33): 14044-14048, 2020 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-32401400

RESUMO

The Au-S bond is the classic way to functionalize gold nanoparticles (AuNPs). However, cleavage of the bond by biothiols and other chemicals is a long-standing problem hindering practical applications, especially in cells. Instead of replacing the thiol by a carbene or selenol for stronger adsorption, it is now shown that the Pt-S bond is much more stable, fully avoiding cleavage by biothiols. AuNPs were deposited with a thin layer of platinum, and an AuNP@Pt-S nanoflare was constructed to detect the miRNA-21 microRNA in living cells. This design retained the optical and cellular uptake properties of DNA-functionalized AuNPs, while showing high-fidelity signaling. It discriminated target cancer cells even in a mixed-cell culture system, where the Au-S based nanoflare was less sensitive. Compared to previous methods of changing the ligand chemistry, coating a Pt shell is more accessible, and previously developed methods for AuNPs can be directly adapted.

17.
Front Immunol ; 11: 785, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32431706

RESUMO

Melanization is a prominent insect humoral response for encapsulation of and killing invading pathogens. It is mediated by a protease cascade composed of a modular serine protease (SP), and clip domain SPs (cSPs), which converts prophenoloxidase (PPO) into active phenoloxidase (PO). To date, melanization pathway in cotton bollworm Helicoverpa armigera, an important agricultural pest, remains largely unclear. To biochemically reconstitute the pathway in vitro, the putative proteases along with modified proteases containing the factor Xa cleavage site were expressed by Drosophila S2 cell expression system. Purified recombinant proteins were used to examine their role in activating PPO. It is revealed that cascade is initiated by a modular SP-SP41, followed by cSP1 and cSP6. The three-step SP41/cSP1/cSP6 cascade could further activate PPO, and the PO activity was significantly enhanced in the presence of two cSP homologs (cSPHs), cSPH11 and cSPH50, suggesting the latter are cofactors for PPO activation. Moreover, baculovirus infection was efficiently blocked by the reconstituted PPO activation cascade, and the effect was boosted by cSPH11 and cSPH50. Taken together, we unraveled a conserved PPO activation cascade in H. armigera, which is similar to that exists in lepidopteran biochemical model Manduca sexta and highlighted its role in antagonizing viral infection.

18.
Chem Commun (Camb) ; 56(46): 6285-6288, 2020 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-32379851

RESUMO

An Al centre-powered graphitic nanozyme derived from a metal organic framework was first developed for a chemodynamic tumor treatment. By virtue of the rapid and efficient generation of ˙OH in the slightly acidic tumor microenvironment, this nanozyme afforded high anti-tumor efficacy both in living cells and in vivo.

20.
Dev Comp Immunol ; 110: 103720, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32344046

RESUMO

The silkworm, Bombyx mori, is utilized as a research model in many aspects of biological studies, including genetics, development and immunology. Previous biochemical and genomic studies have elucidated the silkworm immunity in response to infections elicited by bacteria, fungi, microsporidia, and viruses. The intestine serves as the front line in the battle between insects and ingested harmful microorganisms. In this study, we performed RNA sequencing (RNA-seq) of the larval silkworm midgut after oral infection with the Gram-positive bacterium Bacillus bombysepticus and the Gram-negative bacterium Yersinia pseudotuberculosis. This enables us to get a comprehensive understanding of the midgut responses to bacterial infection. We found that B. bombysepticus induced much stronger immune responses than Y. pseudotuberculosis did. Bacterial infection resulted in more energy consumption including carbohydrates and fatty acids. The midgut immune system was characterized by the generation of reactive oxygen species and antimicrobial peptides. The former played a critical role in eliminating invading bacteria during early stage, while the latter executed during late stage. Our results provide an integrated insight into the midgut systematic responses to bacterial infection.

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