Upconversion dual-photosensitizer-expressing bacteria for near-infrared monochromatically excitable synergistic phototherapy.

Synergistic phototherapy stands for superior treatment prospects than a single phototherapeutic modality. However, the combined photosensitizers often suffer from incompatible excitation mode, limited irradiation penetration depth, and lack of specificity. We describe the development of upconversion dual-photosensitizer-expressing bacteria (UDPB) for near-infrared monochromatically excitable combination phototherapy. UDPB are prepared by integrating genetic engineering and surface modification, in which bacteria are encoded to simultaneously express photothermal melanin and phototoxic KillerRed protein and the surface primary amino groups are derived to free thiols for biorthogonal conjugation of upconversion nanoparticles. UDPB exhibit a near-infrared monochromatic irradiation-mediated dual-activation characteristic as the photothermal conversion of melanin can be initiated directly, while the photodynamic effect of KillerRed can be stimulated indirectly by upconverted visible light emission. UDPB also show living features to colonize hypoxic lesion sites and inhibit pathogens via bacterial community competition. In two murine models of solid tumor and skin wound infection, UDPB separately induce robust antitumor response and a rapid wound healing effect.

Novel fluorescence strategy based on G-quadruplex structure-switching aptamer for enrofloxacin detection in food and environmental samples.

Enrofloxacin (ENR) is widely used in the prevention and treatment of animal infectious diseases, so it is necessary to strengthen the residue detection of this drug in animal-derived food and water environments. In this work, for the first time, we engineered assembly a split ENR aptamer into the G-quadruplex (G4) region to form a new aptamer (G4-ENRA) that provides a more sensitive signal-reporting function while retaining target-specific recognition ability of the aptamer. This rational design effectively overcomes the issue of difficulty in identification probe development. Under the optimized conditions, a response range of 0.05-20 µM and limit of detection of 26.7 nM were obtained by directly detecting fluorescence signals, displaying a comparative advantage over the previously reported methods. Moreover, this method demonstrated satisfactory performance for the ENR detection in various real food and environmental samples, with the detection recoveries ranging from 95.87 % to 104.36 %, illustrating promising applicability prospects.

Advances and prospects of natural dietary polyphenols as G-quadruplex stabilizers in biomedical applications.

G-quadruplexes (G4s) have arrested continuous interest in cancer research, and targeting G4s with small molecules has become an ideal approach for drug development. Plant-based dietary polyphenols have attracted much attention for their remarkable anti-cancer effects. Studies have suggested that polyphenols exhibit interesting scaffolds to bind G4s, which can effectively downregulate the proto-oncogenes by stabilizing those G4 structures. Therefore, this review not only summarizes studies on natural dietary polyphenols (including analogs) as G4 stabilizers, but also reveals their anti-cancer activities. Furthermore, the structural and antioxidant insights of polyphenols with G4s are discussed, and future development is proposed. These insights may pave the way for the development of the next generation of anti-cancer drugs targeting nucleic acids.

Dual-Antigen-Displaying Nanovaccines Elicit Synergistic Immunoactivation for Treating Cancer and Preventing Infectious Complications.

As one of the most common complications, infection causes the majority of mortality in cancer patients. However, therapeutic strategies that can simultaneously suppress tumors and protect patients from infection have been rarely reported. Here, the use of dual-antigen-displaying nanovaccines (DADNs) is described to elicit synergistic immunoactivation for treating cancer and preventing infectious complications. DADNs are prepared by wrapping immunoadjuvant-loaded nanoparticles with a hybrid coating, which is fused from cell membranes that are separately genetically engineered to express tumor and infectious pathogenic antigens. Due to the presence of a dual-antigen combination, DADNs are able to promote the maturation of dendritic cells and more importantly to trigger cross-presentation of both combined antigens. During in vivo investigations, we find that DADNs can reverse immunosuppression by stimulating tumor-associated antigen-specific T-cell responses, resulting in significantly delayed tumor growth in mice. These nanovaccines also elicit effective protective immunity against tumor challenges and induce robust production of pathogenic antigen-specific immunoglobulin G antibody in a prophylactic study. This work offers a unique approach to develop dual-mode vaccines, which are promising for synchronously treating cancer and preventing infection.

Dressing Bacteria With a Hybrid Immunoactive Nanosurface to Elicit Dual Anticancer and Antiviral Immunity.

Approaches capable of simultaneously treating cancer and protecting susceptible patients from lethal infections such as coronavirus disease 2019, are highly desirable but prove to be difficult. Here, dressing bacteria with a hybrid immunoactive nanosurface is reported to elicit dual anticancer and antiviral immunity. A combination of a checkpoint blocking antibody and a virus-specific antigen is covalently conjugated to polydopamine nanoparticles, which can be anchored onto bacterial surface, by a one-step in situ polymerization of dopamine under a cell-friendly condition. By virtue of the ability to colonize and penetrate deep tumor tissue, dressed bacteria enable sustained release and expanded exposure of carried immunoactivators to stimulate immune cells. In addition to a carrier role, bacteria are able to further provoke innate immunity due to the native immunogenicity of the pathogen-associated molecular patterns. Immunization with dressed bacteria promotes the maturation, and activation of antigen-presenting cells, which induces robust humoral and cellular immune responses in tumor-bearing mice. As evidenced by efficient production of viral-antigen-specific immunoglobulin G antibody in serum and significantly suppressed tumor growth in different models, dressing bacteria with a hybrid immunoactive nanosurface paves an avenue to prepare next-generation therapeutics for synergistic treatment and prevention.

A label-free G-quadruplex aptamer fluorescent aptasensor for visual and real-time kanamycin detection in lake and human samples.

Antibiotic abuse is considered a serious problem affecting human health, necessitating that great attention be paid to explore robust, simple and sensitive methods for rapid evaluation. In this paper, we developed a fluorescent aptasensor for visual and real-time kanamycin detection by taking advantage of the label-free strategy based on H-aggregate disassembly of a chiral cyanine dye induced by a G-quadruplex aptamer. The good sensitivity and selectivity enabled this aptasensor to have a detection limit as low as 43 nM and have high specificity for kanamycin recognition. Furthermore, this assay was successfully applied for the detection of kanamycin in lake water and urine with excellent recoveries.

Chemical reaction-mediated covalent localization of bacteria.

Methods capable of manipulating bacterial colonization are of great significance for modulating host-microbiota relationships. Here, we describe a strategy of in-situ chemical reaction-mediated covalent localization of bacteria. Through a simple one-step imidoester reaction, primary amino groups on bacterial surface can be converted to free thiols under cytocompatible conditions. Surface thiolation is applicable to modify diverse strains and the number of introduced thiols per bacterium can be easily tuned by varying feed ratios. These chemically reactive bacteria are able to spontaneously bond with mucous layer by catalyst-free thiol-disulfide exchange between mucin-associated disulfides and newly converted thiols on bacterial surface and show thiolation level-dependent attachment. Bacteria optimized with 9.3 × 107 thiols per cell achieve 170-fold higher attachment in mucin-enriched jejunum, a challenging location for gut microbiota to colonize. As a proof-of-concept application for microbiota transplantation, covalent bonding-assisted localization of an oral probiotic in the jejunum generates an improved remission of jejunal mucositis. Our findings demonstrate that transforming bacteria with a reactive surface provides an approach to chemically control bacterial localization, which is highly desirable for developing next-generation bacterial living bioagents.

Nanocapping-enabled charge reversal generates cell-enterable endosomal-escapable bacteriophages for intracellular pathogen inhibition.

Bacteriophages (phages) are widely explored as antimicrobials for treating infectious diseases due to their specificity and potency to infect and inhibit host bacteria. However, the application of phages to inhibit intracellular pathogens has been greatly restricted by inadequacy in cell entry and endosomal escape. Here, we describe the use of cationic polymers to selectively cap negatively charged phage head rather than positively charged tail by electrostatic interaction, resulting in charge-reversed phages with uninfluenced vitality. Given the positive surface charge and proton sponge effect of the nanocapping, capped phages are able to enter intestinal epithelial cells and subsequently escape from endosomes to lyse harbored pathogens. In a murine model of intestinal infection, oral ingestion of capped phages significantly reduces the translocation of pathogens to major organs, showing a remarkable inhibition efficacy. Our work proposes that simple synthetic nanocapping can manipulate phage bioactivity, offering a facile platform for preparing next-generation antimicrobials.

Long-Acting Protective Ocular Surface by Instilling Adhesive Dual-Antiviral Nanoparticles.

The eye is susceptible to viral infections, causing severe ocular symptoms or even respiratory diseases. Methods capable of protecting the eye from external viral invasion in a long-term and highly effective way are urgently needed but have been proved to be extremely challenging. Here, a strategy of forming a long-acting protective ocular surface is described by instilling adhesive dual-antiviral nanoparticles. Taking pseudotyped severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as a model virus, antiviral agent-loaded nanoparticles are coated with a "double-lock" hybrid cell membrane abundant with integrin-ß1 and angiotensin converting enzyme II (ACE2). After instillation, the presence of integrin-ß1 endows coated nanoparticles with steady adhesion via specific binding to Arg-Gly-Asp sequence on the fibronectin of ocular epithelium, achieving durable retention on the ocular surface. In addition to loaded inhibitors, the exposure of ACE2 can trap SARS-CoV-2 and subsequently neutralize the associated spike protein, playing a dual antiviral effect of the resulting nanoparticles. Adhesive dual-antiviral nanoparticles enabled by coating with a "double-lock" hybrid cell membrane could be a versatile platform for topical long-acting protection against viral infection of the eye.

Polyethyleneimine-complexed charge-reversed yeast cell walls for the enhanced oral delivery of pseudovirus-based antigens.

Oral vaccination has wide applicability in poor areas, particularly during the epidemic periods of infectious diseases. However, successful oral antigen delivery and immune activation remain highly challenging due to the instability of vaccines in gastric acid and the low capture of antigens in the intestine. Here, we present a facile approach for the preparation of a robust oral delivery system via encapsulating antigen-carrying pseudoviruses inside positively charged polyethyleneimine-modified yeast capsules (P-YC). By virtue of the physical barrier role and surface ß-glucan of YC, encapsulated pseudoviruses can be protected from gastric insult and delivered into Peyer's patches via uptake mediated by microfold cells located in the intestinal epithelium. Given the ability to carry diverse antigens, the enhanced oral delivery of pseudoviruses achieved by P-YC provides a versatile platform for the development of various oral vaccines.

Systemic antiviral immunization by virus-mimicking nanoparticles-decorated erythrocytes.

New vaccine technologies are urgently needed to produce safe and effective vaccines in a more timely manner to prevent future infectious disease pandemics. Here, we describe erythrocyte-mediated systemic antiviral immunization, a versatile vaccination strategy that boosts antiviral immune responses by using erythrocytes decorated with virus-mimetic nanoparticles carrying a viral antigen and a Toll-like receptor (TLR) agonist. As a proof of concept, polydopamine nanoparticles were synthesized via a simple in situ polymerization in which the nanoparticles were conjugated with the SARS-CoV-2 spike protein S1 subunit and the TLR7/8 agonist R848. The resulting SARS-CoV-2 virus-mimetic nanoparticles were attached to erythrocytes via catechol groups on the nanoparticle. Erythrocytes naturally home to the spleen and interact with the immune system. Injection of the nanoparticle-decorated erythrocytes into mice resulted in greater maturation and activation of antigen-presenting cells, humoral and cellular immune responses in the spleen, production of S1-specific immunoglobulin G (IgG) antibodies, and systemic antiviral T cell responses than a control group treated with the nanoparticles alone, with no significant negative side effects. These results show that erythrocyte-mediated systemic antiviral immunization using viral antigen- and TLR agonist-presenting polydopamine nanoparticles-a generalizable method applicable to many viral infections-is effective new approach to developing vaccines against severe infectious diseases.

NMR-based plasma metabolomics of adult B-cell acute lymphoblastic leukemia.

Acute lymphoblastic leukemia (ALL) is one of the common malignant tumors. Compared with childhood ALL, the treatment effect of adult B-cell ALL is less effective and remains a big challenge. In order to explore the pathogenesis of adult B-cell ALL and find new diagnostic biomarkers to develop sensitive diagnostic tools, we investigated the plasma metabolites of adult B-cell ALL by using 1H NMR (nuclear magnetic resonance) metabolomics. Relative to healthy controls, adult B-cell ALL patients showed abnormal metabolism, including glycolysis, gluconeogenesis, amino acid metabolism, fatty acid metabolism and choline phospholipid metabolism. What's more important, we also found that the optimal combination of choline, tyrosine and unsaturated lipids has the potential to diagnose and prognose adult B-cell ALL in the clinic.

Selective recognition of DNA parallel G-quadruplexes by 3,8a-disubstituted indolizinones.

Owing to its potential biological relevance, DNA G-quadruplex has been considered as a prospective anti-cancer target. Some known G-quadruplex-interactive N-containing compounds with low cytotoxicity have become prospective anticancer drugs. Here we reported a new type of N-containing alkaloids 3,8a-disubstituted indolizinones, and investigated their substituent effects at 3- and 8a-positions in targeting to DNA c-myc G-quadruplex. And then we used 3-naphtyl-8a-(pyridin-2-yl) substrate I8 as an example, and investigated its ability in targeting to DNA parallel G-quadruplexes in vitro.

Distinct cardiac energy metabolism and oxidative stress adaptations between obese and non-obese type 2 diabetes mellitus.

Background: Little is known about the pathophysiological diversity of myocardial injury in type 2 diabetes mellitus (T2DM), but analyzing these differences is important for the accurate diagnosis and precise treatment of diabetic cardiomyopathy. This study aimed to elucidate the key cardiac pathophysiological differences in myocardial injury between obese and non-obese T2DM from mice to humans. Methods: Obese and non-obese T2DM mouse models were successfully constructed and observed until systolic dysfunction occurred. Changes in cardiac structure, function, energy metabolism and oxidative stress were assessed by biochemical and pathological tests, echocardiography, free fatty acids (FFAs) uptake fluorescence imaging, transmission electron microscopy, etc. Key molecule changes were screened and verified by RNA sequencing, quantitative real-time polymerase chain reaction and western blotting. Further, 28 human heart samples of healthy population and T2DM patients were collected to observe the cardiac remodeling, energy metabolism and oxidative stress adaptations as measured by pathological and immunohistochemistry tests. Results: Obese T2DM mice exhibited more severe cardiac structure remodeling and earlier systolic dysfunction than non-obese mice. Moreover, obese T2DM mice exhibited severe and persistent myocardial lipotoxicity, mainly manifested by increased FFAs uptake, accumulation of lipid droplets and glycogen, accompanied by continuous activation of the peroxisome proliferator activated receptor alpha (PPARα) pathway and phosphorylated glycogen synthase kinase 3 beta (p-GSK-3ß), and sustained inhibition of glucose transport protein 4 (GLUT4) and adipose triglyceride lipase (ATGL), whereas non-obese mice showed no myocardial lipotoxicity characteristics at systolic dysfunction stage, accompanied by the restored PPARα pathway and GLUT4, sustained inhibition of p-GSK-3ß and activation of ATGL. Additionally, both obese and non-obese T2DM mice showed significant accumulation of reactive oxygen species (ROS) when systolic dysfunction occurred, but the NF-E2-related factor 2 (Nrf2) pathway was significantly activated in obese mice, while was significantly inhibited in non-obese mice. Furthermore, the key differences found in animals were reliably verified in human samples. Conclusion: Myocardial injury in obese and non-obese T2DM may represent two different types of complications. Obese T2DM individuals, compared to non-obese individuals, are more prone to develop cardiac systolic dysfunction due to severe and persistent myocardial lipotoxicity. Additionally, anti-oxidative dysfunction may be a key factor leading to myocardial injury in non-obese T2DM.

Pigment Epithelial-Derived Factor Deficiency Accelerates Atherosclerosis Development via Promoting Endothelial Fatty Acid Uptake in Mice With Hyperlipidemia.

Background Endothelial cell injury, induced by dyslipidemia, is the initiation of atherosclerosis, resulting in an imbalance in endothelial fatty acid (FA) transport. Pigment epithelial-derived factor (PEDF) is an important regulator in lipid metabolism. We hypothesized that PEDF is involved in endothelium-mediated FA uptake under hyperlipidemic conditions. Methods and Results Circulating PEDF levels were higher in patients with atherosclerotic cardiovascular disease than in normal individuals. However, decreasing trends of serum PEDF levels were confirmed in both wild-type and apolipoprotein E-deficient mice fed a long-term high-fat diet. Apolipoprotein E-deficient/PEDF-deficient mice were generated by crossing PEDF-deficient mice with apolipoprotein E-deficient mice, and then mice were fed with 24, 36, or 48 weeks of high-fat diet. Greater increases in body fat and plasma lipids were displayed in PEDF-deficient mice. In addition, PEDF deficiency in mice accelerated atherosclerosis, as evidenced by increased atherosclerotic plaques, pronounced vascular dysfunction, and increased lipid accumulation in peripheral tissues, whereas injection of adeno-associated virus encoding PEDF exerted opposite effects. Mechanistically, PEDF inhibited the vascular endothelial growth factor B paracrine signaling by reducing secretion of protein vascular endothelial growth factor B in peripheral tissue cells and decreasing expression of its downstream targets in endothelial cells, including its receptors (namely, vascular endothelial growth factor receptor-1 and neuropilin-1), and FA transport proteins 3 and 4, to suppress endothelial FA uptake, whereas PEDF deletion in mice activated the vascular endothelial growth factor B signaling pathway, thus causing markedly increased lipid accumulation. Conclusions Decreasing expression of PEDF aggravates atherosclerosis by significantly impaired vascular function and enhanced endothelial FA uptake, thus exacerbating ectopic lipid deposition in peripheral tissues.

Direct detection of potassium and lead (II) ions based on assembly-disassembly of a chiral cyanine dye /TBA complex.

A highly selective and sensitive direct detection of potassium (K+) and lead (Pb2+) ions was developed by using the assembly and disassembly of a chiral cyanine dye/TBA complex. The dye DMSB (3-ethyl-2-[3-(3-ethyl-3H-benzoselenazol-2-ylidene)-2-methylprop-1-enyl] benzoselenazolium bromide) loses the ability of self-assembly, but it can be activated by thrombin-binding aptamer (TBA) G-quadruplex structure. And only the TBA G-quadruplex formed in the presence of K+, can strongly induce J-aggregate signals of DMSB. Because the Pb2+ ions can bind and stabilize the TBA G-quadruplex with much higher efficiency than K+, the J-aggregate signals of DMSB falls sharply when the Pb2+ is present. As a result, the assembly and disassembly of DMSB allows the selective detection of 10 µM K+ and 20 nM Pb2+ respectively, even the competitive sodium ion (Na+) was as high as 145 mM. The linear correlation existed between the J-aggregate intensity and the concentration of K+ and Pb2+ over the range of 0.5-5.0 mM and 200-2000 nM, respectively. Moreover, the concentration of K+ (∼3 mM) and Pb2+ (below 20 nM) in human blood serum samples were determined by the present method, which agreed well with inductively coupled plasma mass spectrometry (ICP-MS). This work not only opens a door for the further development of G-quadruplex-based aptasensor in complex real system, but also provides a simple and versatile sensing platform for ion detection in clinic.

Ethyl-substitutive Thioflavin T as a highly-specific fluorescence probe for detecting G-quadruplex structure.

G-quadruplex has attracted considerable attention due to their prevalent distribution in functional genomic regions and transcripts, which can importantly influence biological processes such as regulation of telomere maintenance, gene transcription and gene translation. Artificial receptor study has been developed for accurate identification of G-quadruplex from DNA species, since it is important for the G-quadruplex related basic research, clinical diagnosis, and therapy. Herein, fluorescent dye ThT-E, a derivative of the known fluorescence probe Thioflavin T (ThT), was designed and synthesized to effectively differentiate various G-quadruplex structures from other nucleic acid forms. Compared with methyl groups in ThT, three ethyl groups were introduced to ThT-E, which leads to strengthened affinity, selectivity and little inducing effect on the G-quadruplex formation. More importantly, ThT-E could be served as a visual tool to directly differentiate G-quadruplex solution even with naked eyes under illumination of ultraviolet light. Thus, this probe reported herein may hold great promise for high-throughput assay to screen G-quadruplex, which may widely apply to G-quadruplex-based potential diagnosis and therapy.

Ultrasensitive and high specific detection of non-small-cell lung cancer cells in human serum and clinical pleural effusion by aptamer-based fluorescence spectroscopy.

Lung cancer is the leading cause of cancer-related deaths worldwide, and approximately 85% are diagnosed as non-small-cell lung cancer (NSCLC). However, efficient detection and diagnosis of NSCLC at early stage is still challenging. In this work, we developed a simple, ultrasensitive and high selective strategy for A549 human NSCLC cells detection based on combining the reorganization property of a novel cyanine dye 3,3'-di(3-sulfopropyl)-4,5,4',5'-dibenzo-9-methyl-thiacarbocyanine triethylammonium salt (cy-M) to aptamer S6 G-quadruplex structure having specific affinity to NSCLC cells, which induced a dramatic fluorescence enhancement (~ 104 times). Moreover, this strategy was successfully used for detecting of A549 cancer cells in complex media such as human serum and clinical pleural effusion, which strong indicated that the proposed method could be applied for the early diagnosis of lung cancer.

Novel fluorescent cationic benzothiazole dye that responds to G-quadruplex aptamer as a novel K+ sensor.

A fluorescent cationic benzothiazole dye that selectively targets a G-quadruplex aptamer was designed and synthesized as a K+ sensor. The K+-driven aptamer sensor is based on the strategy of conformational transition from single-stranded DNA to G-quadruplex structure, leading to an amplified fluorescence signal in the reporter. This fluorescent sensor displayed high selectivity for K+, suggesting great potential for practical applications.

Serum Metabolomics of Burkitt Lymphoma Mouse Models.

Burkitt lymphoma (BL) is a rare and highly aggressive type of non-Hodgkin lymphoma. The mortality rate of BL patients is very high due to the rapid growth rate and frequent systemic spread of the disease. A better understanding of the pathogenesis, more sensitive diagnostic tools and effective treatment methods for BL are essential. Metabolomics, an important aspect of systems biology, allows the comprehensive analysis of global, dynamic and endogenous biological metabolites based on their nuclear magnetic resonance (NMR) and mass spectrometry (MS). It has already been used to investigate the pathogenesis and discover new biomarkers for disease diagnosis and prognosis. In this study, we analyzed differences of serum metabolites in BL mice and normal mice by NMR-based metabolomics. We found that metabolites associated with energy metabolism, amino acid metabolism, fatty acid metabolism and choline phospholipid metabolism were altered in BL mice. The diagnostic potential of the metabolite differences was investigated in this study. Glutamate, glycerol and choline had a high diagnostic accuracy; in contrast, isoleucine, leucine, pyruvate, lysine, α-ketoglutarate, betaine, glycine, creatine, serine, lactate, tyrosine, phenylalanine, histidine and formate enabled the accurate differentiation of BL mice from normal mice. The discovery of abnormal metabolism and relevant differential metabolites may provide useful clues for developing novel, noninvasive approaches for the diagnosis and prognosis of BL based on these potential biomarkers.