Targeted delivery of MerTK protein via cell membrane engineered nanoparticle enhances efferocytosis and attenuates atherosclerosis in diabetic ApoE-/- Mice.

BACKGROUND: Clearance of apoptotic cells by efferocytosis is crucial for prevention of atherosclerosis progress, and impaired efferocytosis contributes to the aggravated atherosclerosis. RESULTS: In this study, we found that diabetic ApoE-/- mice showed aggravated atherosclerosis as hyperglycemia damaged the efferocytosis capacity at least partially due to decreased expression of Mer tyrosine kinase (MerTK) on macrophages. To locally restore MerTK in the macrophages in the plaque, hybrid membrane nanovesicles (HMNVs) were thus developed. Briefly, cell membrane from MerTK overexpressing RAW264.7 cell and transferrin receptor (TfR) overexpressing HEK293T cell were mixed with DOPE polymers to produce nanovesicles designated as HMNVs. HMNVs could fuse with the recipient cell membrane and thus increased MerTK in diabetic macrophages, which in turn restored the efferocytosis capacity. Upon intravenous administration into diabetic ApoE-/- mice, superparamagnetic iron oxide nanoparticles (SMN) decorated HMNVs accumulated at the aorta site significantly under magnetic navigation, where the recipient macrophages cleared the apoptotic cells efficiently and thus decreased the inflammation. CONCLUSIONS:  Our study indicates that MerTK decrease in macrophages contributes to the aggravated atherosclerosis in diabetic ApoE-/- mice and regional restoration of MerTK in macrophages of the plaque via HMNVs could be a promising therapeutic approach.

Toward Ultrasound Molecular Imaging of Endothelial Dysfunction in Diabetes: Targets, Strategies, and Challenges.

Diabetes vasculopathy is a significant complication of diabetes mellitus (DM), and early identification and timely intervention can effectively slow the progression. Accumulating studies have shown that diabetes causes vascular complications directly or indirectly through a variety of mechanisms. Direct imaging of the endothelial molecular changes not only identifies the early stage of diabetes vasculopathy but also sheds light on the precise treatment. Targeted ultrasound contrast agent (UCA)-based ultrasound molecular imaging (UMI) can noninvasively detect the expression status of molecular biomarkers overexpressed in the vasculature, thereby being a potential strategy for the diagnosis and treatment response evaluation of DM. Amounts of efforts have been focused on identification of the molecular targets expressed in the vasculature, manufacturing strategies of the targeted UCA, and the clinical translation for the diagnosis and evaluation of therapeutic efficacy in both micro- and macrovasculopathy in DM. This review summarizes the latest research progress on endothelium-targeted UCA and discusses their promising future and challenges in diabetes vasculopathy theranostics.

Profibrogenic macrophage-targeted delivery of mitochondrial protector via exosome formula for alleviating pulmonary fibrosis.

Pulmonary fibrosis (PF) is a devastating lung disease with limited treatment options. During this pathological process, the profibrogenic macrophage subpopulation plays a crucial role, making the characterization of this subpopulation fundamentally important. The present study revealed a positive correlation between pulmonary macrophages with higher mitochondrial mass (Mømitohigh) and fibrosis. Among the Mømitohigh subpopulation of CD206+ M2, characterized by higher expression of dynamin 1-like (Drp1), as determined by flow cytometry and RNA-seq analysis, a therapeutic intervention was developed using an exosome-based formula composed of pathfinder and therapeutics. A pathfinder exosome called "exosomeMMP19 (ExoMMP19)", was constructed to display matrix metalloproteinase-19 (MMP19) on the surface to locally break down the excessive extracellular matrix (ECM) in the fibrotic lung. A therapeutic exosome called "exosome therapeutics (ExoTx)", was engineered to display D-mannose on the surface while encapsulating siDrp1 inside. Prior delivery of ExoMMP19 degraded excessive ECM and thus paved the way for ExoTx to be delivered into Mømitohigh, where ExoTx inhibited mitochondrial fission and alleviated PF. This study has not only identified Mømitohigh as profibrotic macrophages but it has also provided a potent strategy to reverse PF via a combination of formulated exosomes.

Rex1BD and the 14-3-3 protein control heterochromatin organization at tandem repeats by linking RNAi and HDAC.

Tandem DNA repeats are often organized into heterochromatin that is crucial for genome organization and stability. Recent studies revealed that individual repeats within tandem DNA repeats can behave very differently. How DNA repeats are assembled into distinct heterochromatin structures remains poorly understood. Here, we developed a genome-wide genetic screen using a reporter gene at different units in a repeat array. This screen led to identification of a conserved protein Rex1BD required for heterochromatin silencing. Our structural analysis revealed that Rex1BD forms a four-helix bundle structure with a distinct charged electrostatic surface. Mechanistically, Rex1BD facilitates the recruitment of Clr6 histone deacetylase (HDAC) by interacting with histones. Interestingly, Rex1BD also interacts with the 14-3-3 protein Rad25, which is responsible for recruiting the RITS (RNA-induced transcriptional silencing) complex to DNA repeats. Our results suggest that coordinated action of Rex1BD and Rad25 mediates formation of distinct heterochromatin structure at DNA repeats via linking RNAi and HDAC pathways.

Monoallelic deleterious MUTYH mutations generate colorectal cancer: A case report.

Here we reported a particular case of MUTYH-associated polyposis (MAP) that had only one rare heterozygous variant, but some particular clinical manifestations contributed to occur in this male patient by only one defective MUTYH allele were worth of further investigation. We reported a case of MAP. It is about a 33-year-old man with chief complaints of hematochezia who had multiple polyps that were found in his colon via colonoscopy. He followed his doctor's advice and performed a genetic analysis examination. Germline test was positive for a major heterozygous variant: chr1:45800165 on the MUTYH gene. MUTYH gene sequence analysis confirmed the following heterozygous variant: c.55CT (p.R19X) in exon 2 (ClinVar NM_001128425). Unfortunately, his mother and daughter have the ILK variant according to genetic analysis. However, this variant at the site was not detected in his father. Various types of polyps were found on repeated colonoscopy, which tended to become latent cancerous in the future. This case indicated that awareness of the risk of carcinogenesis of polyps in carriers of monoallelic variants might accordingly increase, and our understanding of the type of genetically related disease will be enhanced by us.

Targeted elimination of senescent cells by engineered extracellular vesicles attenuates atherosclerosis in ApoE-/- mice with minimal side effects.

Senescent cells in plaques emerge as a detrimental factor for atherosclerosis (AS), for which targeted senolysis might be a promising therapeutic strategy. The development of safe and efficient senolytics for senescent cell eradication by targeted delivery is greatly needed. Methods: Pro-apoptotic intelligent Bax (iBax)-overexpressing plasmid was constructed by molecular cloning, in which Bax CDS was fused to miR-122 recognition sites. Extracellular vesicle-based senolytics (EViTx) were developed to be conjugated with magnetic nanoparticles on the surface, iBax mRNA encapsulated inside, and BAX activator BTSA1 incorporated into the membrane. EViTx was characterized, and in vivo distribution was tracked via fluorescence imaging. The therapeutic effects of EViTx on AS and its systemic side effects were analyzed in ApoE-/- mice. Results: Magnetic nanoparticles, iBax mRNA and BAX activator BTSA1 were efficiently loaded into/onto EViTx. With external magnetic field navigation, EViTx was delivered into atherosclerotic plaques and induced significant apoptosis in senescent cells regardless of origins. Repeated delivery of EViTx via tail vein injection has achieved high therapeutic efficacy in ApoE-/- mice. Notably, EViTx is inevitably accumulated in liver cells, while the iBax mRNA was translationally repressed by miR-122, an endogenous miRNA highly expressed in hepatocytes, and thus the liver cells are protected from the potential toxicity of Bax mRNA. Conclusion: Our work demonstrated that magnetic EV-based delivery of iBax mRNA and the BAX activator BTSA1, efficiently induced apoptosis in recipient senescent cells in atherosclerotic plaques. This strategy represents a promising treatment approach for AS and other age-related diseases.

Fluorinated covalent-organic polymers as stationary phase for analysis of organic fluorides by open-tubular capillary electrochromatography.

Fluorinated porous materials, which can provide specific fluorine-fluorine interaction, hold great promise for fluoride analysis. Here, a novel fluorinated covalent-organic polymer was prepared by using 2,4,6-tris(4-aminophenyl)-1,3,5-triazine and 2,3,5,6-tetrafluorotelephtal aldehyde as the precursors and introduced as stationary phase for open-tubular capillary electrochromatography. The as-synthesized fluorinated covalent-organic polymer and the modified capillary column were characterized by infrared spectroscopy, scanning electron microscopy, and energy dispersive X-ray spectrometry. Based on strong hydrophobic interaction and fluorine-fluorine interaction provided by fluorinated covalent-organic polymer coating layer, the modified column showed powerful separation selectivity toward hydrophobic compounds, organic fluorides, and fluorinated pesticides. Additionally, the fluorinated covalent-organic polymer with good porosity and regular shape was uniformly and tightly coated on the capillary inner wall. The obtained highest column efficiency could reach up to 1.2 × 105 plates⋅m-1 for fluorophenol. The loading capacity of the modified column can reach 141 pmol for trifluorotoluene. Besides, the relative standard deviations of retention times for intraday run (n = 5), interday run (n = 3), and between columns (n = 3) were all less than 2.55%. Significantly, this novel fluorinated material-based stationary phase shows great application potential in fluorides analysis.

Modular Hydrogel Vaccine for Programmable and Coordinate Elicitation of Cancer Immunotherapy.

Immunotherapy holds great promise for the treatment of malignant cancer. However, the lack of sufficient tumor neoantigens and incomplete dendritic cell (DC) maturation compromise the efficacy of immunotherapy. Here, a modular hydrogel-based vaccine capable of eliciting a powerful and sustained immune response is developed. Briefly, CCL21a and ExoGM-CSF+Ce6 (tumor cell-derived exosomes with granulocyte-macrophage colony-stimulating factor (GM-CSF) mRNA encapsulated inside and sonosensitizer chlorin e6 (Ce6) incorporated in the surface) are mixed with nanoclay and gelatin methacryloyl, forming the hydrogel designated as CCL21a/ExoGM-CSF+Ce6 @nanoGel. The engineered hydrogel releases CCL21a and GM-CSF with a time gap. The earlier released CCL21a diverts the tumor-draining lymph node (TdLN) metastatic tumor cells to the hydrogel. Consequently, the trapped tumor cells in the hydrogel, in turn, engulf the Ce6-containing exosomes and thus are eradicated by sonodynamic therapy (SDT), serving as the antigen source. Later, together with the remnant CCL21a, GM-CSF produced by cells engulfing ExoGM-CSF+Ce6 continuously recruits and provokes DCs. With the two programmed modules, the engineered modular hydrogel vaccine efficiently inhibits tumor growth and metastasis via diverting TdLN metastatic cancer to hydrogel, killing the trapped tumor cells, and eliciting prolonged and powerful immunotherapy in an orchestrated manner. The strategy would open an avenue for cancer immunotherapy.

Homology directed telomere clustering, ultrabright telomere formation and nuclear envelope rupture in cells lacking TRF2B and RAP1.

Double-strand breaks (DSBs) due to genotoxic stress represent potential threats to genome stability. Dysfunctional telomeres are recognized as DSBs and are repaired by distinct DNA repair mechanisms. RAP1 and TRF2 are telomere binding proteins essential to protect telomeres from engaging in homology directed repair (HDR), but how this occurs remains unclear. In this study, we examined how the basic domain of TRF2 (TRF2B) and RAP1 cooperate to repress HDR at telomeres. Telomeres lacking TRF2B and RAP1 cluster into structures termed ultrabright telomeres (UTs). HDR factors localize to UTs, and UT formation is abolished by RNaseH1, DDX21 and ADAR1p110, suggesting that they contain DNA-RNA hybrids. Interaction between the BRCT domain of RAP1 and KU70/KU80 is also required to repress UT formation. Expressing TRF2∆B in Rap1-/- cells resulted in aberrant lamin A localization in the nuclear envelope and dramatically increased UT formation. Expressing lamin A phosphomimetic mutants induced nuclear envelope rupturing and aberrant HDR-mediated UT formation. Our results highlight the importance of shelterin and proteins in the nuclear envelope in repressing aberrant telomere-telomere recombination to maintain telomere homeostasis.

Ultrasound Responsive Nanovaccine Armed with Engineered Cancer Cell Membrane and RNA to Prevent Foreseeable Metastasis.

Cancer vaccine has been considered as a promising immunotherapy by inducing specific anti-tumor immune response. Rational vaccination at suitable time to efficiently present tumor associated antigen will boost tumor immunity and is badly needed. Here, a poly (lactic-co-glycolic acid) (PLGA)-based cancer vaccine of nanoscale is designed, in which engineered tumor cell membrane proteins, mRNAs, and sonosensitizer chlorin e6 (Ce6) are encapsulated at high efficiency. The nanosized vaccine can be efficiently delivered into antigen presentation cells (APCs) in lymph nodes after subcutaneous injection. In the APCs, the encapsulated cell membrane and RNA from engineered cells, which have disturbed splicing resembling the metastatic cells, provide neoantigens of metastatic cancer in advance. Moreover, the sonosensitizer Ce6 together with ultrasound irradiation promotes mRNA escape from endosome, and augments antigen presentation. Through 4T1 syngeneic mouse model, it has been proved that the proposed nanovaccine is efficient to elicit antitumor immunity and thus prevent cancer metastasis.

Exosome-Based Mitochondrial Delivery of circRNA mSCAR Alleviates Sepsis by Orchestrating Macrophage Activation.

Sepsis is one of the most common causes of death, which is closely related to the uncontrolled systemic inflammation. Dysregulation of M1 macrophage polarization is the primary contributor to serious inflammation. In this study, it is revealed that the murine homologue of circRNA SCAR (steatohepatitis-associated circRNA ATP5B regulator), denoted as circRNA mSCAR hereafter, decreases in the macrophages of septic mice, which correlates with the excessive M1 polarization. To restore circRNA mSCAR in mitochondria, exosomes encapsulated with circRNA mSCAR are further electroporated with poly-D-lysine-graft-triphenylphosphine (TPP-PDL), and thus TPP-PDL facilitates the bound circRNA delivered into mitochondria when the exosomes engulf by the recipient cells. In in vivo septic mouse model and in vitro cell model, it is shown that the exosome-based mitochondria delivery system delivers circRNA mSCAR into mitochondria preferentially in the macrophages, favoring macrophage polarization toward M2 subtype. Accordingly, the systemic inflammation is attenuated by exosome-based mitochondrial delivery of circRNA mSCAR, together with alleviated mortality. Collectively, the results uncover the critical role of circRNA mSCAR in sepsis, and provide a promising approach to attenuate sepsis via exosome-based mitochondrial delivery of circRNA mSCAR.

Supramolecular Host-Guest Hydrogel Based on γ-Cyclodextrin and Carboxybenzyl Viologen Showing Reversible Photochromism and Photomodulable Fluorescence.

Much effort has been devoted to the development of supramolecular hydrogels due to their broad applications and conveniently controllable properties. Here, we demonstrate a novel supramolecular host-guest hydrogel, which is constructed by the host γ-CD complexed with the guest 1-(4-carboxybenzyl)-4,4'-bipyridinium chloride (1+·Cl-) through the π···π interaction, hydrogen bonding, and host-guest interactions. The supramolecular hydrogel [1+@γ-CD]n exhibits reversible electron transfer photochromic behavior and photomodulable fluorescence. The excellent photochromic and fluorescence properties support the practical utility of the supramolecular hydrogel as a visual display and anti-counterfeiting material.

An inclusion complex of cucurbit[7]uril with benzimidazolyl benzyl viologen exhibits fluorescence and photochromic properties.

In order to investigate the photochromic mechanism of photochromic materials based on supramolecular host-guest systems, we designed and synthesized a unique viologen derivative (benzimidazolyl benzyl viologen, guest 1·Cl3), which does not contain oxygen atoms. The binding interaction of guest 13+ with host cucurbit[7]uril (Q[7]) was investigated by various techniques. The obtained supramolecular host-guest complex 13+@Q[7] exhibits interesting fluorescence emission and reversible photochromism. The ESR and XPS experimental data suggest that the photochromic process of the complex 13+@Q[7] comes from the electron transfer from the carbonyl O atoms of the host Q[7] to the bipyridinium N atoms of the guest 13+.

Phase separation of Dri1 contributes to heterochromatin formation in Schizosaccharomyces pombe.

The RNA binding protein Dri1 facilitates heterochromatin assembly via the RNAi pathway and histone deacetylases (HDAC). Dri1 contains an intrinsically disordered region (IDR) and three zinc fingers at its C-terminus, which are important for its role in heterochromatin silencing. Both IDR and zinc fingers have been implicated in mediating liquid-liquid phase separation (LLPS). In this study, we investigated the phase separation properties of Dri1. We observed that Dri1 undergoes phase separation in vitro . Dri1 also exhibits liquid-like behavior in vivo . Combined with our previous findings, our data support a model in which the phase-separated condensates formed by Dri1 may help recruit RNAi components and HDAC to mediate heterochromatin assembly.

A light-responsive molecular switch based on cucurbit[7]uril and 1,1'-bis(benzyl)-4-[2-(4-pyridyl)-vinyl]-pyridinium dibromide displaying white light emission.

By using 1H NMR, ESI-MS and UV spectra, a novel light-responsive molecular switch constructed using 1,1'-bis(benzyl)-4-[2-(4-pyridyl)-vinyl]-pyridinium (12+) and cucurbit[7]uril (Q[7]) is demonstrated. The E- to Z-isomerization of the double bond in 12+ results in the transition of the switching states from the 1 : 2 complex E-12+@Q[7]2 to the stable 1 : 1 complex Z-12+@Q[7]. In particular, both the 1 : 2 complex and the 1 : 1 complex can emit cold white fluorescence under UV light.

Ultrasound triggered topical delivery of Bmp7 mRNA for white fat browning induction via engineered smart exosomes.

BACKGROUND: Efficient and topical delivery of drugs is essential for maximized efficacy and minimized toxicity. In this study, we aimed to design an exosome-based drug delivery platform endowed with the ability of escaping from phagocytosis at non-target organs and controllably releasing drugs at targeted location. RESULTS: The swtichable stealth coat CP05-TK-mPEG was synthesized and anchored onto exosomes through the interaction between peptide CP05 and exosomal surface marker CD63. Chlorin e6 (Ce6) was loaded into exosomes by direct incubation. Controllable removal of PEG could be achieved by breaking thioketal (TK) through reactive oxygen species (ROS), which was produced by Ce6 under ultrasound irradiation. The whole platform was called SmartExo. The stealth effects were analyzed in RAW264.7 cells and C57BL/6 mice via tracing the exosomes. To confirm the efficacy of the engineered smart exosomes, Bone morphogenetic protein 7 (Bmp7) mRNA was encapsulated into exosomes by transfection of overexpressing plasmid, followed by stealth coating, with the exosomes designated as SmartExo@Bmp7. Therapeutic advantages of SmartExo@Bmp7 were proved by targeted delivering Bmp7 mRNA to omental adipose tissue (OAT) of obese C57BL/6 mice for browning induction. SmartExo platform was successfully constructed without changing the basic characteristics of exosomes. The engineered exosomes effectively escaped from the phagocytosis by RAW264.7 and non-target organs. In addition, the SmartExo could be uptaken locally on-demand by ultrasound mediated removal of the stealth coat. Compared with control exosomes, SmartExo@Bmp7 effectively delivered Bmp7 mRNA into OAT upon ultrasound irradiation, and induced OAT browning, as evidenced by the histology of OAT and increased expression of uncoupling protein 1 (Ucp1). CONCLUSIONS: The proposed SmartExo-based delivery platform, which minimizes side effects and maximizing drug efficacy, offers a novel safe and efficient approach for targeted drug delivery. As a proof, the SmartExo@Bmp7 induced local white adipose tissue browning, and it would be a promising strategy for anti-obesity therapy.

Vulnerability and Resilience of Urban Traffic to Precipitation in China.

The concept of Healthy Cities, introduced by the World Health Organization, demonstrates the value of health for the whole urban system. As one of the most important components of urban systems, transportation plays an important role in Healthy Cities. Many transportation evaluation systems focus on factors such as road networks, parking spaces, transportation speed, accessibility, convenience, and commuting time, while the vulnerability and resilience of urban transportation are rarely evaluated. This study presents the preliminary progress in the evaluation of traffic vulnerability and resilience during precipitation events in 39 Chinese cities. Traffic congestion index data, derived from the Baidu Map Smart Transportation Platform, and rainfall data, derived from NASA's global precipitation measurement, are utilized. Traffic vulnerability index, traffic resilience index, and the corresponding quantitative methods are proposed, and the analysis results are presented. This study is of value in improving the understanding of urban traffic vulnerability and resilience, and in enabling the quantitative evaluation of them in urban health assessment and the Healthy Cities program.