Aptamer BT200 is protective against myocardial ischemia-reperfusion injury in mice.

BACKGROUND: Myocardial ischemia-reperfusion (MI/R) injury tends to affect cardiac function and leads to poor patient prognosis, and there is still not effectively targeted drug to develop anti-Von Willebrand Factor (VWF) aptamer in acute coronary heart disease. However, the newly anti-VWF aptamer BT200 is not only applied for stroke and hemophilia, but also for anti-thrombolism function in clinical development. The role of BT200 in acute myocardial injury during MI/R is still unknown. OBJECTIVES: To investigate the cardioprotective effect of aptamer BT200 in an experiment model of MI/R. METHODS: C57BL/6 mice were subjected to 30-minute ischemia and 24-hour reperfusion to establish myocardial I/R model. Mice were treated with intravenous injection of cy3-labeled BT200 and were observed by an in vivo imaging system at different time points. Then, mice were sampled and evaluated by echocardiography, Evans-TTC staining, histopathologic, western blotting, and real-time qPCR assays to detect cardiac injury and inflammation response post 24-hour reperfusion. RESULTS: BT200 aptamer can enter and infiltrate into the ischemic myocardium post 24-hour reperfusion. BT200 was shown to inhibit VWF A1 activity and prolong bleeding time in MI/R mice. Moreover, BT200-treated mice had a significant reduction in infarct size and an improvement in cardiac function post-MI/R. BT200 treatment can also alleviate MI/R-induced microvascular obstruction, inflammation response, and cardiomyocyte apoptosis. CONCLUSIONS: Pharmacologic targeting of VWF with BT200 alleviates acute MI/R injury in a murine model, and may be a novel therapy strategy for acute myocardial infarction.

Serum Metabolomics Analysis Revealed Metabolic Pathways Related to AECOPD Complicated with Anxiety and Depression.

Background: Anxiety and depression are two of the most common comorbidities of COPD, which can directly lead to the number of acute exacerbations and hospitalizations of COPD patients and reduce their quality of life. At present, there are many studies on anxiety and depression in stable COPD, but few studies on anxiety and depression in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) patients. Objective: We aim to explore the changes of serum metabolomics in AECOPD complicated with anxiety and depression and to provide some clues for further understanding its pathogenesis. Methods: This is an observational high-throughput experimental study based on retrospective data extraction. Twenty-one AECOPD with anxiety and depressive patients and 17 healthy controls (HCs) were retrospectively enrolled in the Second Affiliated Hospital of Anhui Medical University. Hamilton anxiety scale (HAMA) and Hamilton depression scale (HAMD) for anxiety and depression were used to assess the patients with AECOPD. Untargeted metabolomics analysis was carried out to investigate different molecules in the serum of all participants. General information of all participants, baseline data and clinical measurement data of AECOPD patients were collected. Statistical analysis and bioinformatics analysis were performed to reveal different metabolites and perturbed metabolic pathways. Results: A total of 724 metabolites in positive ionization mode and 555 metabolites in negative ionization mode were different in AECOPD patients with anxiety and depression. The 1,279 serum metabolites could be divided into 77 categories. Based on multivariate and univariate analysis, 74 metabolites were detected in positive ionization mode, and 60 metabolites were detected in negative ionization as differential metabolites. The 134 metabolites were enriched in 18 pathways, including biosynthesis of unsaturated fatty acids, aldosterone synthesis and secretion, protein digestion and absorption, ovarian steroidogenesis, long-term depression, retrograde endocannabinoid signaling, and so on. Conclusion: This work highlights the key metabolites and metabolic pathways disturbed in AECOPD patients with anxiety and depression. These findings support the use of metabolomics to understand the pathogenic mechanisms involved in AECOPD patients with anxiety and depression.

Do social economic status modify the association between air pollution and depressive or anxiety symptoms? A big sample cross-sectional study from the rural areas of Central China.

BACKGROUND: Fewer studies have examined the relationship between air pollution and depressive or anxiety symptoms in rural residents. Social economic status (SES), as an important indicator of the current state of socioeconomic development, we know little about how it modifies the relationship between air pollution and symptoms of depression or anxiety. METHODS: The patient health questionnaire (PHQ-2) and generalized anxiety scale (GAD-2) were used to learn about the prevalence of depressive and anxiety symptoms, the social economic status of the participants was categorized into two levels: lower and higher, and a binary logistic regression model was used to analyze the relationship between air pollution and residents' symptoms of depression or anxiety. RESULTS: A total of 10,670 adults were enrolled in this study, of which a total of 1292 participants suffered from depressive symptoms and 860 suffered from anxiety symptoms. Short-term exposure to PM2.5 and O3, singly or in combination, may be associated with the onset of depression symptoms, and there was a significant interaction between SES and exposure to PM2.5 or O3. Residents of areas with higher SES may have a lower risk of suffering from anxiety symptoms after O3 exposure compared to participants living in lower SES. LIMITATIONS: The study was a cross-sectional study, which may have lowered the quality level of the evidence. CONCLUSIONS: Short-term PM2.5 and O3 exposure may be associated with an increased prevalence risk of depressive symptoms. Higher levels of SES may reduce the adverse effects of air pollution on depressive or anxiety symptoms.

Functionalizing Sgc8-Paclitaxel Conjugates with F-Base Modifications: Targeted Drug Delivery with Optimized Cardiac Safety.

Recent advancements in cancer treatment have improved patient prognoses, but chemotherapy induced cardiotoxicity remains a prevalent concern. This study explores the potential of F-base-modified aptamers for targeted drug delivery, focusing on their impact on cardiotoxicity. From the phosphoramidite, F-base-functionalized Sgc8-F23 was prepared in an automated and programmable way, which was further reacted with paclitaxel (PTX) to give the F-base- modified aptamer Sgc8-paclitaxel conjugates (Sgc8-F23-PTX) efficiently. The conjugate exhibited prolonged circulation time and enhanced efficacy as a precision anticancer drug delivery system. Echocardiographic assessments revealed no exacerbation of cardiac dysfunction after myocardial infarction (MI) and no pathological changes or increased apoptosis in non-infarcted cardiac regions. Autophagy pathway analysis showed no discernible differences in Sgc8-F23-PTX-treated cardiomyocytes compared with controls, in contrast to the increased autophagy with nanoparticle albumin-bound-paclitaxel (Nab-PTX). Similarly, apoptosis analysis showed no significant differences. Moreover, Sgc8-F23-PTX exhibited no inhibitory effect on hERG, hNav1.5, or hCav1.2 channels. These findings suggest the safety and efficacy of F-base-modified Sgc8 aptamers for targeted drug delivery with potential clinical applications. Further research is warranted for clinical translation and exploration of other drug carriers.

Unlocking the Potential of Pterostilbene: A Pharmaceutical Element for Aptamer-Based Nanomedicine.

Natural compounds like pterostilbene (PTE) have gained recognition for their various biological activities and potential health benefits. However, challenges related to bioavailability and limited clinical efficacy have prompted efforts to strengthen their therapeutic potential. To meet these challenges, we herein rationally designed and successfully synthesized a pharmaceutical phosphoramidite that allows for the programmable incorporation of PTE into oligonucleotides. The resultant aptamer-PTE conjugate can selectively bind to cancer cells, leading to a specific internalization and drug release. Moreover, compared with free PTE, the conjugate exhibits superior cytotoxicity in cancer cells. Specifically, in a zebrafish xenograft model, the nanomedicine effectively inhibits tumor growth and neovascularization, highlighting its potential for targeted antitumor therapy. This approach presents a promising avenue for harnessing the therapeutic potential of natural compounds via a nanomedicine solution.

Dynamically Reconfigurable on-Chip Polarimeters Based on Nanoantenna Enabled Polarization Dependent Optoelectronic Computing.

On-chip polarization detectors have attracted extensive research interest due to their filterless and ultracompact architecture. However, their polarization-dependent photoresponses cannot be dynamically adjusted, hindering the development toward intelligence. Here, we propose dynamically reconfigurable polarimetry based on in-sensor differentiation of two self-powered photoresponses with orthogonal polarization dependences and tunable responsivities. Such a device can be electrostatically configured in an ultrahigh polarization extinction ratio (PER) mode, where the PER tends to infinity, a Stokes parameter direct sensing mode, where the photoresponse is proportional to S1 or S2 with high accuracy (RMSES1 = 1.5%, RMSES2 = 2.0%), or a background suppressing mode, where the target-background polarization contrast is singularly enhanced. Moreover, the device achieves a polarization angle sensitivity of 0.51 mA·W-1·degree-1 and a specific polarization angle detectivity of 2.8 × 105 cm·Hz1/2·W·degree-1. This scheme is demonstrated throughout the near-to-long-wavelength infrared range, and it will bring a leap for next-generation on-chip polarimeters.

The First-in-Human Whole-Body Dynamic Pharmacokinetics Study of Aptamer.

Serving as targeting ligands, aptamers have shown promise in precision medicine. However, the lack of knowledge of the biosafety and metabolism patterns in the human body largely impeded aptamers' clinical translation. To bridge this gap, here we report the first-in-human pharmacokinetics study of protein tyrosine kinase 7 targeted SGC8 aptamer via in vivo PET tracking of gallium-68 (68Ga) radiolabeled aptamers. The specificity and binding affinity of a radiolabeled aptamer, named 68Ga[Ga]-NOTA-SGC8, were maintained as proven in vitro. Further preclinical biosafety and biodistribution evaluation confirmed that aptamers have no biotoxicity, potential mutation risks, or genotoxicity at high dosage (40 mg/kg). Based on this result, a first-in-human clinical trial was approved and carried out to evaluate the circulation and metabolism profiles, as well as biosafety, of the radiolabeled SGC8 aptamer in the human body. Taking advantage of the cutting-edge total-body PET, the aptamers' distribution pattern in the human body was acquired in a dynamic fashion. This study revealed that radiolabeled aptamers are harmless to normal organs and most of them are accumulated in the kidney and cleared from the bladder via urine, which agrees with preclinical studies. Meanwhile, a physiologically based pharmacokinetic model of aptamer was developed, which could potentially predict therapeutic responses and plan personalized treatment strategies. This research studied the biosafety and dynamic pharmacokinetics of aptamers in the human body for the first time, as well as demonstrated the capability of novel molecular imaging fashion in drug development.

Artificial Base-Directed In Vivo Assembly of an Albumin-siRNA Complex for Tumor-Targeting Delivery.

RNA interference (RNAi) mediated by short interfering RNA (siRNA) is a promising method for cancer treatment, but the clinical application is hampered by several limitations, including metabolic instability, lack of tumor specificity, and poor cellular uptake. To meet these challenges, we have explored the possibility of structure modification of siRNA with artificial bases for property optimization. A series of siRNAs functionalized with different numbers of hydrophobic base F are prepared for screening. The interactions of plasma proteins with F-base-modified siRNA (F-siRNA) are investigated, and it is identified that the interaction with serum albumin is dominant. Experiments revealed that the introduction of F bases conferred modified siRNA with improved tumor-specific accumulation, prolonged circulatory retention time, and better tissue permeability. Mechanistic studies indicated that the F base induces the formulation of a stable siRNA-albumin complex, which transports siRNA to tumor tissues selectively owing to an enhanced permeability and retention (EPR) effect of albumin. The F base also facilitates the binding of siRNA to transport-associated proteins on the cell membrane, enabling its cellular internalization. Together, these data demonstrate that F base modification confers siRNA-enhanced cellular uptake and biostability and specific accumulation in tumor tissue, which provides a new approach for the development of siRNA-based cancer therapeutics.

Molecular elements: novel approaches for molecular building.

Classically, a molecular element (ME) is a pure substance composed of two or more atoms of the same element. However, MEs, in the context of this review, can be any molecules as elements bonded together into the backbone of synthetic oligonucleotides (ONs) with designed sequences and functions, including natural A, T, C, G, U, and unnatural bases. The use of MEs can facilitate the synthesis of designer molecules and smart materials. In particular, we discuss the landmarks associated with DNA structure and related technologies, as well as the extensive application of ONs, the ideal type of molecules for intervention therapy aimed at correcting disease-causing genetic errors (indels). It is herein concluded that the discovery of ON therapeutics and the fabrication of designer molecules or nanostructures depend on the ME concept that we previously published. Accordingly, ME will be our focal point as we discuss related research directions and perspectives in making molecules and materials. This article is part of the theme issue 'Reactivity and mechanism in chemical and synthetic biology'.

Artificial Base-Directed In Vivo Formulation of Aptamer-Drug Conjugates with Albumin for Long Circulation and Targeted Delivery.

Aptamer-drug conjugates (ApDCs) are potential targeted pharmaceutics, but their clinical applications are hampered by fast clearance in blood. Herein we report the construction of ApDCs modified with artificial base F and the study of biological activities. Two types of F-base-modified ApDCs were prepared, Sgc8-paclitaxel by conjugation and Sgc8-gemcitabine, by automated solid-phase synthesis. In vitro experiments showed that F-base-modified ApDCs retain the specificity of the aptamer to target cells and the biological stability is improved. In vivo studies demonstrated that the circulatory time is increased by up to 55 h or longer, as the incorporated F base leads to a stable ApDC-albumin complex as the formulation for targeted delivery. Moreover, conjugated drug molecules were released efficiently and the drug (paclitaxel) concentration in the tumor site was improved. The results demonstrate that an F-base-directed ApDC-albumin complex is a potential platform for drug delivery and targeted cancer therapy.

The construction of oligonucleotide-cycloastragenol and the renoprotective effect study.

Traditional Chinese Medicine (TCM) provides unique therapeutic effects for many diseases with identified efficacy during long practice. Astragalus Membranaceus (AM) is the Chinese herbal applied for kidney injury in the clinic, but it remains challenging to further enhance the efficacy. Cycloastragenol (CAG) is the ingredient isolated from AM with poor water solubility, which has shown a renoprotective effect. Herein we designed and synthesized the corresponding solid-phase module of CAG, from which CAG as a pharmaceutical element was incorporated into oligonucleotides (ON) as an ON-CAG conjugate in a programmable way by a DNA synthesizer. Cell viability study demonstrated that ON-CAG conjugate remains similar renoprotective effect as that of CAG, which efficiently recovers the activity of HK-2 cells pretreated with cisplatin. Similarly, in the renal cells treated with the conjugate, the biomarkers of kidney injury such as KIM-1 and IL-18 are downregulated, and cytokines are reduced as treated with anti-inflammatory agents. Overall, we have managed to incorporate a hydrophobic ingredient of TCM into ON and demonstrate the oligonucleotide synthesis technology as a unique approach for the mechanism study of TCM, which may facilitate the discovery of new therapeutics based on TCM.

Site-Specific Radioiodination of Oligonucleotides with a Phenolic Element in a Programmable Approach.

Radioiodination of oligonucleotides provides an extra modality for nucleic acid-based theranostics with potential applications. Herein, we report the design and synthesis of a phosphoramidite embedded with a phenolic moiety and demonstrate that oligonucleotides can be readily functionalized with phenol as a precursor by general DNA synthesis. It was identified that the introduction of the precursor does not block the specificity of an aptamer, and the radioiodination is applicable to both DNA and RNA oligonucleotides in a site-specific approach with a commercial kit.

Spatial distribution and influencing mechanism of CO2, N2O and CH4 in the Pearl River Estuary in summer.

Estuaries, considered as the important carbon dioxide (CO2), nitrous oxide (N2O) and methane (CH4) sources to the atmosphere, are increasingly affected by near-bottom hypoxia. However, the impact of estuarine hypoxic zone development on GHGs production and discharge remains poorly understood due to the seasonal and spatially distributed heterogeneity of estuarine hypoxia occurrence and the lack of simultaneous monitoring of the distribution of bottom hypoxic waters and the vertical distribution of GHGs. Here, we conducted high spatial resolution vertical stratification sampling and analysis of water column GHGs in the Pearl River Estuary (PRE), a large estuary with frequent hypoxia in recent years. Our results showed that Pearl River runoff is the main source of GHGs in the PRE. Strong nitrification is an important N2O production mechanism in the PRE. In situ generation of water and resuspension of surface sediments were the main sources of CH4 in bottom water, while massive organic matter (OM) mineralization is the main driver of CO2 in bottom water. The development of a hypoxic zone in the PRE significantly increased the concentration of N2O and CH4 in the bottom water and thus increased air-water fluxes. The air-water fluxes of N2O, CH4 and CO2 of PRE in summer were 31.9 ± 7.5 µmol m-2 d-1, 192.5 ± 229.4 µmol m-2 d-1 and 51.9 ± 14.1 mmol m-2 d-1, respectively. This study reveals that GHGs fluxes from estuarine waters to the atmosphere will increase significantly with increasing eutrophication caused by human activities and the expansion of hypoxic zones in estuarine waters.

Engineering Aptamers with Selectively Enhanced Biostability in the Tumor Microenvironment.

Aptamers are emerging as promising molecular tools in cancer-targeted theranostics. Improving their in vivo stability has been a critical issue in promoting clinical translation, but such efforts could lead to more serious side effects resulting from prolonged retention in healthy organs. To address this problem, we developed an environment-responsive stabilization strategy for the selective enhancement of aptamer biostability in the tumor microenvironment (TME). Briefly, by means of the end extension of an ATP-responsive protection (ARP) module, the designed aptamer could be protected from nuclease degradation through the specific incorporation of ATP. Based on our in vivo results, this ARP-aptamer probe was effectively accumulated in tumors via aptamer-based molecular recognition. It showed selectively prolonged tumor retention time, but rapid digestion in healthy organs. Our strategy should provide a new paradigm for the development of organ-specific nucleic acid-based imaging and therapeutic agents.

Programmable manipulation of oligonucleotide-albumin interaction for elongated circulation time.

Oligonucleotide (ON) therapeutics are emerging as a new generation of medicine with tremendous potential, but their clinical translation is hampered by inferior stability and short circulation time in the human body. Here, we report a general approach to manipulating the interaction between ONs and albumin by modulating hydrophobicity. A series of DNA aptamer derivatives were designed and prepared by programmable synthesis as an ON library with a gradient of hydrophobic base 'F'. In vitro experiments revealed that the introduction of two F bases at both ends of ONs enhanced the biostability without sacrificing biological activities, while the binding affinity toward albumin was dramatically increased with Kd in the range of 100 nM to 1 µM. In vivo imaging confirmed the immediate formation of the aptamer-albumin complex after the injection, and the circulation time of the aptamer was dramatically elongated owing to the enhanced biostability and retarded renal excretion. The programmable incorporation of the F base provides a general approach to regulating albumin-binding affinity and enhancing the stability of aptamers in vivo, conferring aptamer therapeutics prolonged circulation time to meet clinical requirements.

Programmable Repurposing of Existing Drugs as Pharmaceutical Elements for the Construction of Aptamer-Drug Conjugates.

Converting marketed drug molecules into phosphoramidites may present a potential strategy to facilitate the development of aptamer-drug conjugates (ApDCs) by a DNA synthesizer in a programmable way; however, quite limited methods were reported. Herein, we demonstrated a general approach by repurposing camptothecin (CPT) species. Commonly used inactive ingredients in pharmaceuticals are investigated and selected as a bonding moiety, from which 2-mercaptoethoxy ethanol and thioglycerol were efficiently incorporated with CPT to give the precursors. Cell viability and molecular docking results of the precursors supported that incorporation of the bonding moiety would not interrupt the inhibitory activity. Therefore, corresponding phosphoramidites were prepared as pharmaceutical elements, and a series of ApDCs were constructed automatically by solid-phase synthesis. Biological studies revealed that CPT elements could be specifically delivered to HCT116 cells by an aptamer and released inside cells. This kind of programmable repurposing may take advantage of established safety data and efficacy of existing drugs resulting in a faster development of ApDCs.

Aptamers as Versatile Molecular Tools for Antibody Production Monitoring and Quality Control.

Antibody drugs have been used to treat many diseases, and to date, this has been the most rapidly growing drug class. However, the lack of suitable methods for real-time and high-throughput monitoring of antibody production and quality control has been a hindrance to the further advancement of antibody drugs or biosimilars. Therefore, we herein report a versatile tool for one-step fluorescence monitoring of antibody production by using aptamer probes selected through the in vitro SELEX method. In this case, DNA aptamers were selected against the humanized IgG1 antibody drug trastuzumab with high specificity and affinity with a Kd value of aptamer CH1S-3 of 10.3 nM. More importantly, the obtained aptamers were able to distinguish native from heat-treated, whereas antibodies failed this test. On the basis of the advantages of rapid detection for aptamers, we designed aptamer molecular beacons for direct and sensitive detection of trastuzumab in complex samples. Unlike traditional antibody-based ELISA, the signal was observed directly upon interaction with the target without the need for time-consuming binding and multiple washing steps. To further highlight biomedical applications, the use of aptamers as potential tools for quality control and traceless purification of antibody drugs was also demonstrated. Thus, aptamers are shown to be promising alternatives for antibody production monitoring, quality control, and purification, providing technical support to accelerate antibody drug development.

Conformational Conversion Enhances Cellular Uptake of F Base Double-Strand-Conjugated Oligonucleotides.

Artificial bases have emerged as a useful tool to expand genetic alphabets and biomedical applications of oligonucleotides. Herein, we reported that the conformation conversion enhances cellular uptake of hydrophobic 3,5-bis(trifluoromethyl)benzene (F) base double-strand-conjugated oligonucleotides. The formation of the F base double-strand caged the hydrophobic F base in the duplex strand, thus preventing F base from interacting with cells to some extent. However, upon conversion of F base double-strand-conjugated oligonucleotide to F base single-strand-conjugated oligonucleotide, F bases then were allowed to interact with cells by stronger hydrophobic interactions, followed by cellular uptake. The results were concluded as a pairing-induced cage effect of F base and have the potential for the construction of stimuli-responsive cellular uptake of functional nucleic acids.

Molecular domino reactor built by automated modular synthesis for cancer treatment.

Rationale: A cascade, or domino, reaction consists of two, or more, consecutive reactions such that subsequent reactions occur only if some chemical functionality has first been established in the prior step. However, while construction of predesigned and desired molecular domino reactors in a tailored manner is a valuable endeavor, it is still challenging. Methods: To address this challenge, we herein report an aptamer-based photodynamic domino reactor built through automated modular synthesis. The engineering of this reactor takes advantage of the well-established solid-phase synthesis platform to incorporate a photosensitizer into G-quadruplex/ hemin DNAzyme at the molecular level. Results: As a proof of concept, our photodynamic domino reactor, termed AS1411/hemin- pyrochlorophyll A, achieves in vivo photodynamic domino reaction for efficient cancer treatment by using a high concentration of hydrogen peroxide (H2O2) in the tumor microenvironment (TME) to produce O2, followed by consecutive generation of singlet oxygen (1O2) using the pre-produced O2. More specifically, phosphoramidite PA (pyrochlorophyll A) is coupled to aptamer AS1411 to form AS1411-PA ApDC able to simultaneously perform in vivo targeted imaging and photodynamic therapy (PDT). The insertion of hemin into the AS1411 G-quadruplex was demonstrated to alleviate tumor hypoxia by decomposition of H2O2 to produce O2. This was followed by the generation of 1O2 by PA to trigger cascading amplified PDT. Conclusion: Therefore, this study provides a general strategy for building an aptamer-based molecular domino reactor through automated modular synthesis. By proof of concept, we further demonstrate a novel method of achieving enhanced PDT, as well as alleviating TME hypoxia at the molecular level.