Synthetic biology based on bacteria has been displayed in antitumor therapy and shown good performance. In this study, an engineered bacterium Escherichia coli MG1655 is designed with NDH-2 enzyme ...(respiratory chain enzyme II) overexpression (Ec-pE), which can colonize in tumor regions and increase localized H
O
generation. Following from this, magnetic Fe
O
nanoparticles are covalently linked to bacteria to act as a catalyst for a Fenton-like reaction, which converts H
O
to toxic hydroxyl radicals (•OH) for tumor therapy. In this constructed bioreactor, the Fenton-like reaction occurs with sustainably synthesized H
O
produced by engineered bacteria, and severe tumor apoptosis is induced via the produced toxic •OH. These results show that this bioreactor can achieve effective tumor colonization, and realize a self-supplied therapeutic Fenton-like reaction without additional H
O
provision.
Synthetic biology based on bacteria has been displayed in antitumor therapy and shown good performance. In this study, an engineered bacterium Escherichia coli MG1655 is designed with NDH‐2 enzyme ...(respiratory chain enzyme II) overexpression (Ec‐pE), which can colonize in tumor regions and increase localized H2O2 generation. Following from this, magnetic Fe3O4 nanoparticles are covalently linked to bacteria to act as a catalyst for a Fenton‐like reaction, which converts H2O2 to toxic hydroxyl radicals (•OH) for tumor therapy. In this constructed bioreactor, the Fenton‐like reaction occurs with sustainably synthesized H2O2 produced by engineered bacteria, and severe tumor apoptosis is induced via the produced toxic •OH. These results show that this bioreactor can achieve effective tumor colonization, and realize a self‐supplied therapeutic Fenton‐like reaction without additional H2O2 provision.
A Fenton‐like bioreactor based on bacteria is reported for tumor therapy without exogenous H2O2 provision. It is found that this bioreactor can achieve effective tumor colonization, and realize a self‐supplied therapeutic Fenton‐like reaction without additional H2O2 provision.
Effective reversal of tumor immunosuppression is of critical importance in cancer therapy. A multifunctional delivery vector that can effectively deliver CRISPR‐Cas9 plasmid for β‐catenin knockout to ...reverse tumor immunosuppression is constructed. The multi‐functionalized delivery vector is decorated with aptamer‐conjugated hyaluronic acid and peptide‐conjugated hyaluronic acid to combine the tumor cell/nuclear targeting function of AS1411 with the cell penetrating/nuclear translocation function of TAT‐NLS. Due to the significantly enhanced plasmid enrichment in malignant cell nuclei, the genome editing system can induce effective β‐catenin knockout and suppress Wnt/β‐catenin pathway, resulting in notably downregulated proteins involved in tumor progression and immunosuppression. Programmed death‐ligand 1 (PD‐L1) downregulation in edited tumor cells not only releases the PD‐1/PD‐L1 brake to improve the cancer killing capability of CD8+ T cells, but also enhances antitumor immune responses of immune cells. This provides a facile strategy to reverse tumor immunosuppression and to restore immunosurveillance and activate anti‐tumor immunity.
An aptamer/peptide‐functionalized delivery vector is constructed to effectively deliver CRISPR‐Cas9 plasmid to tumor cells for β‐catenin knockout to eliminate tumor immunosuppression. The significantly decreased programmed death‐ligand 1 (PD‐L1) in edited tumor cells not only releases the PD‐1/PD‐L1 brake to improve the cancer‐killing capability of T cells, but also enhances the antitumor immune responses of the immune cells co‐cultured with edited tumor cells.
By leveraging the ability of Shewanella oneidensis MR‐1 (S. oneidensis MR‐1) to anaerobically catabolize lactate through the transfer of electrons to metal minerals for respiration, a lactate‐fueled ...biohybrid (Bac@MnO2) was constructed by modifying manganese dioxide (MnO2) nanoflowers on the S. oneidensis MR‐1 surface. The biohybrid Bac@MnO2 uses decorated MnO2 nanoflowers as electron receptor and the tumor metabolite lactate as electron donor to make a complete bacterial respiration pathway at the tumor sites, which results in the continuous catabolism of intercellular lactate. Additionally, decorated MnO2 nanoflowers can also catalyze the conversion of endogenous hydrogen peroxide (H2O2) into generate oxygen (O2), which could prevent lactate production by downregulating hypoxia‐inducible factor‐1α (HIF‐1α) expression. As lactate plays a critical role in tumor development, the biohybrid Bac@MnO2 could significantly inhibit tumor progression by coupling bacteria respiration with tumor metabolism.
MnO2 nanoflowers were modified on the cell surface of electrochemically active bacteria, S. oneidensis MR‐1. The biohybrids, which couple bacterial respiration with tumor metabolism, can catabolize intercellular lactate and prevent intracellular lactate production in the tumor, thereby inducing significant tumor inhibition.
Many applications of CRISPR/Cas9-mediated genome editing require Cas9-induced non-homologous end joining (NHEJ), which was thought to be error prone. However, with directly ligatable ends, ...Cas9-induced DNA double strand breaks may be repaired preferentially by accurate NHEJ.
In the repair of two adjacent double strand breaks induced by paired Cas9-gRNAs at 71 genome sites, accurate NHEJ accounts for about 50% of NHEJ events. This paired Cas9-gRNA approach underestimates the level of accurate NHEJ due to frequent + 1 templated insertions, which can be avoided by the predefined Watson/Crick orientation of protospacer adjacent motifs (PAMs). The paired Cas9-gRNA strategy also provides a flexible, reporter-less approach for analyzing both accurate and mutagenic NHEJ in cells and in vivo, and it has been validated in cells deficient for XRCC4 and in mouse liver. Due to high frequencies of precise deletions of defined "3n"-, "3n + 1"-, or "3n + 2"-bp length, accurate NHEJ is used to improve the efficiency and homogeneity of gene knockouts and targeted in-frame deletions. Compared to "3n + 1"-bp, "3n + 2"-bp can overcome + 1 templated insertions to increase the frequency of out-of-frame mutations. By applying paired Cas9-gRNAs to edit MDC1 and key 53BP1 domains, we are able to generate predicted, precise deletions for functional analysis. Lastly, a Plk3 inhibitor promotes NHEJ with bias towards accurate NHEJ, providing a chemical approach to improve genome editing requiring precise deletions.
NHEJ is inherently accurate in repair of Cas9-induced DNA double strand breaks and can be harnessed to improve CRISPR/Cas9 genome editing requiring precise deletion of a defined length.
Cancer cells, with unique their metabolism, frequently exhibit a high level of redox homeostasis, which could be a feasible target for cancer treatment. Here, liquid metal (LM) nanoparticles are used ...as a template to guide the growth of yolk‐shell structured LM@MnO2 (LMN). With yolk‐shell structures, LMNs is applied to load with cinnamaldehyde (CA) (CLMN) and further coated with hyaluronic acid (HA) to construct the CA&LM@MnO2‐HA nanoflowers (CLMNF) for cancer targeted treatment. Owing to the urchin‐like structured shell, it is found that the obtained CLMNF particles rapidly deplete glutathione (GSH) and produce manganese ions, which further facilitate hydrogen peroxide converting into hydroxyl radical (·OH) for cancer cell killing. Accompanying the depletion of GSH, the balance of intracellular redox homeostasis tilts towards oxidation, resulting in amplified oxidative damage caused by CA, eventually, leading to the apoptosis of cancer cells. Combined with the remarkable near infrared (NIR) photothermal conversion properties, the novel structured CLMNF exhibits favorable inhibition of tumors in vivo, indicating that using nanoflowers to induce intracellular oxidative/thermal stress damage could be a promising strategy for anticancer treatment.
Yolk‐shell structured nanoflowers induce intracellular oxidative/thermal stress damage for cancer treatment. By using liquid metal as a template, the yolk‐shell structured manganese dioxide nanoflowers are rapidly constructed through an in situ surface reduction process. Benefiting from the guidance of multimode imaging, the nanoparticles exhibit satisfactory inhibition of tumor growth in vivo.
Abstract
Background
Due to post-cleavage residence of the Cas9-sgRNA complex at its target, Cas9-induced DNA double-strand breaks (DSBs) have to be exposed to engage DSB repair pathways. Target ...interaction of Cas9-sgRNA determines its target binding affinity and modulates its post-cleavage target residence duration and exposure of Cas9-induced DSBs. This exposure, via different mechanisms, may initiate variable DNA damage responses, influencing DSB repair pathway choices and contributing to mutational heterogeneity in genome editing. However, this regulation of DSB repair pathway choices is poorly understood.
Results
In repair of Cas9-induced DSBs, repair pathway choices vary widely at different target sites and classical nonhomologous end joining (c-NHEJ) is not even engaged at some sites. In mouse embryonic stem cells, weakening the target interaction of Cas9-sgRNA promotes bias towards c-NHEJ and increases target dissociation and reduces target residence of Cas9-sgRNAs in vitro. As an important strategy for enhancing homology-directed repair, inactivation of c-NHEJ aggravates off-target activities of Cas9-sgRNA due to its weak interaction with off-target sites. By dislodging Cas9-sgRNA from its cleaved targets, DNA replication alters DSB end configurations and suppresses c-NHEJ in favor of other repair pathways, whereas transcription has little effect on c-NHEJ engagement. Dissociation of Cas9-sgRNA from its cleaved target by DNA replication may generate three-ended DSBs, resulting in palindromic fusion of sister chromatids, a potential source for CRISPR/Cas9-induced on-target chromosomal rearrangements.
Conclusions
Target residence of Cas9-sgRNA modulates DSB repair pathway choices likely through varying dissociation of Cas9-sgRNA from cleaved DNA, thus widening on-target and off-target mutational spectra in CRISPR/Cas9 genome editing.
Rationale and objective
Paeoniflorin has been reported to exhibit antidepressant-like effects in several animal model depression; and it also exerts a neuroprotective effect. In the present study, we ...investigated the effects of paeoniflorin administration on depression-like behaviors and cognitive abilities in mice subjected to chronic unpredictable mild stress (CUMS), an animal model associated with depressive disorders and cognitive deficits.
Methods
We administered paeoniflorin (20 mg/kg), which is the main active constituent extracted from
Paeonia lactiflora
Pall. and exerts multiple pharmacological actions, to CUMS mice. Subsequently, animals were subjected to tests of depression-like behavior including the sucrose preference test, the forced swimming test and the tail suspension test. The Morris water maze (MWM) task was applied to evaluate learning and memory capacity. Hippocampal CA1 long-term potentiation (LTP) was recorded. Dendritic spine density and the expression levels of brain-derived neurotrophic factor (BDNF) and postsynaptic density protein 95 (PSD95) in the hippocampus were also investigated.
Results
The administration of paeoniflorin protected against CUMS-induced depression-like behavior. Paeoniflorin also improved the performance of CUMS mice in the MWM. The impairment of hippocampal CA1 LTP caused by CUMS was also reversed. Furthermore, paeoniflorin administration prevented decreases in dendritic spine density and in the expression of BDNF and PSD95 in the hippocampus of CUMS mice.
Conclusion
Our observations suggest that paeoniflorin is a potential antidepressant that protects against cognitive impairment in depression.
In this study, a novel perovskite quantum dot (QD) spray‐synthesis method is developed by combining traditional perovskite QD synthesis with the technique of spray pyrolysis. By utilizing this new ...technique, the synthesis of cubic‐shaped perovskite QDs with a homogeneous size of 14 nm is demonstrated, which shows an unprecedented stable absolute photoluminescence quantum yield ≈100% in the solution and even in the solid‐state neat film. The highly emissive thin films are integrated with light emission devices (LEDs) and organic light emission displays (OLEDs). The color conversion type QD‐LED (ccQD‐LED) hybrid devices exhibit an extremely saturated green emission, excellent external quantum efficiency of 28.1%, power efficiency of 121 lm W−1, and extraordinary forward‐direction luminescence of 8 500 000 cd m−2. The conceptual ccQD‐OLED hybrid display also successfully demonstrates high‐definition still images and moving pictures with a 119% National Television System Committee 1931 color gamut and 123% Digital Cinema Initiatives‐P3 color gamut. These very‐stable, ultra‐bright perovskite QDs have the properties necessary for a variety of useful applications in optoelectronics.
Spray‐synthesized perovskite quantum dots (QDs) show an unprecedented cubic shape, and a stable photoluminescence quantum yield of ≈100% in both solution and the solid‐state neat film. QD‐LED (light emission device) and QD‐OLED (organic light emission display) hybrid devices exhibit an excellent external quantum efficiency of 28.1%, a power efficiency of 121 lm W−1, and successfully demonstrate high‐definition motion pictures.
In this study, we developed a general method to decorate plasmonic gold nanorods (GNRs) with a CD44-targeting functional polymer, containing a hyaluronic acid (HA)-targeting moiety and a small ...molecule Glut1 inhibitor of diclofenac (DC), to obtain GNR/HA-DC. This nanosystem exhibited the superiority of selectively sensitizing tumor cells for photothermal therapy (PTT) by inhibiting anaerobic glycolysis. Upon specifically targeting CD44, sequentially time-dependent DC release could be achieved by the trigger of hyaluronidase (HAase), which abundantly existed in tumor tissues. The released DC depleted the Glut1 level in tumor cells and induced a cascade effect on cellular metabolism by inhibiting glucose uptake, blocking glycolysis, decreasing ATP levels, hampering heat shock protein (HSP) expression, and ultimately leaving malignant cells out from the protection of HSPs to stress (e.g., heat), and then tumor cells were more easy to kill. Owing to the sensitization effect of GNR/HA-DC, CD44 overexpressed tumor cells could be significantly damaged by PTT with an enhanced therapeutic efficiency in vitro and in vivo.
PDF
