Regulation on Toll-like Receptor 4 and Cell Barrier Function by Rab26 siRNA-loaded DNA Nanovector in Pulmonary Microvascular Endothelial Cells

Enhanced delivery of CRISPR/Cas9 system based on biomimetic nanoparticles for hepatitis B virus therapy

The persistent presence of covalently closed circular DNA (cccDNA) in hepatocyte nuclei poses a significant obstacle to achieving a comprehensive cure for hepatitis B virus (HBV). Current applications of CRISPR/Cas9 for targeting and eliminating cccDNA have been confined to in vitro studies due to challenges in stable cccDNA expression in animal models and the limited non-immunogenicity of delivery systems. This study addresses these limitations by introducing a novel non-viral gene delivery system utilizing Gemini Surfactant (GS). The developed system creates stable and targeted CRISPR/Cas9 nanodrugs with a negatively charged surface through modification with red blood cell membranes (RBCM) or hepatocyte membranes (HCM), resulting in GS-pDNA@Cas9-CMs complexes. These GS-pDNA complexes demonstrated complete formation at a 4:1 w/w ratio. The in vitro transfection efficiency of GS-pDNA-HCM reached 54.61%, showing homotypic targeting and excellent safety. Additionally, the study identified the most effective single-guide RNA (sgRNA) from six sequences delivered by GS-pDNA@Cas9-HCM. Using GS-pDNA@Cas9-HCM, a significant reduction of 96.47% in in vitro HBV cccDNA and a 52.34% reduction in in vivo HBV cccDNA were observed, along with a notable decrease in other HBV-related markers. The investigation of GS complex uptake by AML-12 cells under varied time and temperature conditions revealed clathrin-mediated endocytosis (CME) for GS-pDNA and caveolin-mediated endocytosis (CVME) for GS-pDNA-HCM and GS-pDNA-RBCM. In summary, this research presents biomimetic gene-editing nanovectors based on GS (GS-pDNA@Cas9-CMs) and explores their precise and targeted clearance of cccDNA using CRISPR/Cas9, demonstrating good biocompatibility both in vitro and in vivo. This innovative approach provides a promising therapeutic strategy for advancing the cure of HBV.

ROS induced the Rab26 promoter hypermethylation to promote cigarette smoking-induced airway epithelial inflammation of COPD through activation of MAPK signaling

Cigarette smoking (CS) exposure-induced airway inflammatory responses drive the occurrence and development of emphysema and chronic obstructive pulmonary disease (COPD). However, its precise mechanisms have not been fully elucidated. In this study, we explore the role of Rab26 in CS exposure modulating the inflammatory response of airway epithelium and the novel mechanism of CS exposure regulation Rab26. These data showed that CS exposure and H₂O₂ (a type of ROS) suppressed the expression of Rab26 and increased the expression of DNMT3b in vivo and in vitro. GEO data analysis found the level of Rab26 was decreased in the lung tissue of COPD patients. CSE-induced ROS promoted DNA methylation of the Rab26 promoter and inhibited its promoter activity by elevating the DNMT3b level. Antioxidants N-Acetyl-l-cysteine (NAC), 5-Aza-2'-deoxycytidine (5-AZA) (DNA methylation inhibitor) and DNMT3B siRNA alleviated CSE's inhibitory effect on Rab26 expression in vitro. Importantly, NAC alleviated the improved expression of Rab26 and reduced DNMT3B expression, in the airway of smoking exposure as well as attenuated the inflammatory response in vivo. Overexpression of Rab26 attenuated CSE-induced production of inflammatory mediators through part inactivation of p38 and JNK MAPK. On the contrary, silencing Rab26 enhanced p38 and JNK activation and aggravated inflammatory response. These findings suggest that ROS-mediated Rab26 promoter hypermethylation is a critical step in cigarette smoking-induced airway epithelial inflammatory response. Restoring Rab26 in the airway epithelium might be a potential strategy for treating airway inflammation and COPD.

Attenuating endothelial leakiness with self-assembled DNA nanostructures for pulmonary arterial hypertension

Vascular endothelium dysfunction plays an important role in oncological and pulmonary diseases. Endothelial barrier dysfunction is the initial step of pulmonary vascular remodeling (PVR) and pulmonary arterial hypertension. Upregulation of a pro-autophagy protein Atg101 in the endothelial cells triggered a cascade of intracellular events that leads to endothelial dysfunction through apoptosis. Herein, we proposed a strategy that used endothelial targeting DNA nanostructures to deliver Atg101 siRNA (siAtg101) as a safe, biocompatible "band-aid" to restore pulmonary arterial endothelial barrier integrity within the intricate milieu of pulmonary cells and the pulmonary vasculature. The siAtg101 and aptamer conjugated DNA nanostructures were found to attenuate hypoxia-induced pulmonary endothelial leakiness with surprisingly high selectivity and efficacy. Further in vivo study revealed that functionalized DNA nanostructures likewise attenuated the vascular remodeling in a monocrotaline-induced PVR mouse model. Mechanistically, functionalized DNA nanostructures suppressed PVR by knocking down Atg101, which in turn, downregulated Beclin-1 and subsequently upregulated VE-cadherin to restore endothelial cells' adherin junctions. This work opened a new window for future nanomaterial design that directly addresses the interfacial endothelial cell layer that often stands between the blood and many diseased sites of nanotherapeutic interest.

Rab26 controls secretory granule maturation and breakdown in Drosophila

At the onset of Drosophila metamorphosis, plenty of secretory glue granules are released from salivary gland cells and the glue is deposited on the ventral side of the forming (pre)pupa to attach it to a dry surface. Prior to this, a poorly understood maturation process takes place during which secretory granules gradually grow via homotypic fusions, and their contents are reorganized. Here we show that the small GTPase Rab26 localizes to immature (smaller, non-acidic) glue granules and its presence prevents vesicle acidification. Rab26 mutation accelerates the maturation, acidification and release of these secretory vesicles as well as the lysosomal breakdown (crinophagy) of residual, non-released glue granules. Strikingly, loss of Mon1, an activator of the late endosomal and lysosomal fusion factor Rab7, results in Rab26 remaining associated even with the large glue granules and a concomitant defect in glue release, similar to the effects of Rab26 overexpression. Our data thus identify Rab26 as a key regulator of secretory vesicle maturation that promotes early steps (vesicle growth) and inhibits later steps (lysosomal transport, acidification, content reorganization, release, and breakdown), which is counteracted by Mon1.

Preparation and characterization of a gemini surfactant-based biomimetic complex for gene delivery

Gemini surfactants (GS) have been explored as non-viral gene delivery systems. Nevertheless, their cytotoxicity and the limitations in the in vivo studies have impeded their development. To attenuate toxicity and further explore their possibilities in gene delivery, a series of GS (18-7-18)-based gene delivery systems complexed with red blood cell membranes (RBCM) or/and DOPE-PEG₂₀₀₀ (DP) were prepared and evaluated. EGFP-encoding plasmids were delivered via GS-based complexes and the efficiency of gene transfection was evaluated by imaging of the major organs after intravenous administration in mice and qPCR quantification in hepatocytes. In order to assess the safety of GS-based complexes, the hemolysis test, serum biochemical indices, H&E staining and CCK-8 test were examined. The results revealed that EGFP was primarily expressed in livers, and all complexes showed minimal acute toxicity to major organs. Moreover, we found that the dual incorporation of RBCM and DP could significantly elevate the transfection efficiency and cell viability in hepatocytes. Overall, the results indicated that GS-based complexes possessed great potential as vectors for gene delivery both in vivo and in vitro and the dual incorporation of RBCM and DP could be a promising gene delivery approach with high transfection efficacy and low toxicity.

Framework nucleic acids enabled pulmonary artery endothelial cell growth inhibition by targeting microRNA-152

Pulmonary artery vascular endothelial dysfunction plays a pivotal role in the occurrence and progression of pulmonary vascular remodeling (PVR). To address this, aberrantly expressed non-coding microRNAs (miRNAs) are excellent therapeutic targets in human pulmonary artery endothelial cells (HPAECs). Here, we discovered and validated the overexpression of miRNA-152 in HPAECs under hypoxia and its role in endothelial cell dysfunction. We constructed a framework nucleic acids nanostructure that harbors six protruding single-stranded DNA segments that can fully hybridize with miRNA-152 (DNT-152). DNT-152 was efficiently taken up by HPAECs with increasing time and concentration; it markedly induced apoptosis, and inhibited HPAEC growth under hypoxic conditions. Mechanistically, DNT-152 silenced miRNA-152 expression and upregulated its target gene Meox2, which subsequently inhibited the AKT/mTOR signaling pathway. These results indicate that miRNA-152 in HPAECs may be an excellent therapeutic target against PVR, and that framework nucleic acids with carefully designed sequences are promising nanomedicines for noncancerous cells and diseases.

Novel Circulating Tumour Cell-Related Risk Model Indicates Prognosis and Immune Infiltration in Lung Adenocarcinoma

Background

Lung adenocarcinoma (LUAD) is the most common histological subtype of lung cancer (LC) and one of the leading causes of cancer-related death worldwide. LUAD has a low survival rate owing to tumour invasion and metastasis. Circulating tumour cells (CTCs) are precursors of distant metastasis, which are considered to adopt the characteristics of cancer stem cells (CSCs). Therefore, analysing the risk factors of LUAD from the perspective of CTCs may provide novel insights into the metastatic mechanisms and may help to develop diagnostic and therapeutic strategies.

Methods

A total of 447 patients from TCGA dataset were included in the training cohort, and 460 patients from the GEO dataset were included in the validation cohort. A CTC-related-gene risk model was constructed using LASSO penalty–Cox analysis, and its predictive value was further verified. Functional enrichment analysis was performed on differentially expressed genes (DEGs), followed by immune correlation analysis based on the results. In addition, western blot, CCK-8 and colony formation assays were used to validate the biological function of RAB26 in LUAD.

Results

A novel in-silico CTC-related-gene risk model, named the CTCR model, was constructed, which successfully divided patients into the high- and low-risk groups. The prognosis of the high-risk group was worse than that of the low-risk group. ROC analysis revealed that the risk model outperformed traditional clinical markers in predicting the prognosis of patients with LUAD. Further study demonstrated that the identified DEGs were significantly enriched in immune-related pathways. The immune score of the low-risk group was higher than that of the high-risk group. In addition, RAB26 was found to promote the proliferation of LUAD.

Conclusion

A prognostic risk model based on CTC-related genes was successfully constructed, and the relationship between DEGs and tumour immunity was analysed. In addition, RAB26 was found to promote the proliferation of LUAD cells.

Synchronous conjugation of i-motif DNA and therapeutic siRNA on the vertexes of tetrahedral DNA nanocages for efficient gene silence

The functionality of DNA biomacromolecules has been widely excavated, as therapeutic drugs, carriers, and functionalized modification derivatives. In this study, we developed a series of DNA tetrahedron nanocages (Td), via synchronous conjugating different numbers of i-(X) and therapeutic siRNA on four vertexes of tetrahedral DNA nanocage (aX-Td@bsiRNA, a+b = 4). This i-motif-conjugated Td exhibited good endosomal escape behaviours in A549 tumor cells, and the escape efficiency was affected by the number of i-motif. Furthermore, the downregulating mRNA and protein expression level of epidermal growth factor receptor (EGFR) caused by this siRNA embedded Td were verified in A549 cells. The tumor growth inhibition efficiency of the 2X-Td@2siRNA treated group in tumor-bearing mice was significantly higher than that of non-i-motif-conjugated Td@2siRNA (3.14-fold) and free siRNA (3.63-fold). These results demonstrate a general strategy for endowing DNA nanostructures with endosomal escape behaviours to achieve effective in vivo gene delivery and therapy.

Study on the effect and mechanism of NFKBIA on cervical cancer progress in vitro and in vivo

AIM

NFKBIA is frequently encountered. However, its expression and relevance of the proliferation, invasion, and migration in human cervical cancer (CC) remain unclear. The role and novel mechanism of NFKBIA in CC progression were investigated in this study.

METHODS

We analyzed the expression of NFKBIA in CC and adjacent normal tissues and explored the proliferation, migration, and invasion of HeLa cells by treating with either wild-type NFKBIA plasmid or NFKBIA siRNA. Effect of NFKBIA on the epithelial-mesenchymal transition (EMT) and the β-catenin-mediated transcription of target genes were evaluated subsequently.

RESULTS

NFKBIA expression was lower in CC tissues than that of adjacent tissues. An obvious dysregulation of NFKBIA overexpression was revealed in CC cell proliferation, invasion, and migration, which differed from the effect of knockdown NFKBIA. NFKBIA overexpression facilitated the expression of both phosphorylated β-catenin and E-cadherin protein. It inhibited the expression of vimentin, TWIST, as well as downstream targets of β-catenin including c-MYC, TCF-4 and MMP14. Conversely, NFKBIA silencing elevated the expression of c-MYC, TCF-4, and MMP14, and promoted the EMT in HeLa cells. Both endogenous and exogenous NFKBIA interacted with β-catenin. Moreover, β-catenin overexpression stemmed effects of NFKBIA on the proliferation, migration, and invasion of HeLa cells. By overexpressing NFKBIA in vivo, the volume and size of tumors were notably decreased, while no obvious alteration was found in mice body weight.

CONCLUSION

By inhibiting β-catenin-mediated transcription, NFKBIA functioning as a tumor suppressor might be introduced as a novel anti-metastatic agent for the treatment of targeted CC.

When Rab GTPases meet innate immune signaling pathways

Ras-related protein in brain (Rab) GTPases, the subfamily of small GTP-binding proteins superfamily, play a vital role in regulating and controlling vesicles' transport between different membrane-bound organelles. As the first-line defense against invading pathogens, the host's innate immune system recognizes various pathogen-associated molecular patterns through a series of membrane-bound or cytoplasmic pathogen recognition receptors to activate the downstream signaling pathway and induce the type I interferons (IFN-I). Numerous studies have demonstrated that Rab GTPases participate in innate immunity by regulating transmembrane signals' transduction and the transport, adhesion, anchoring, and fusion of vesicles. However, the underlying mechanism of Rab GTPases regulating innate immunity is not entirely understood. A comprehensive understanding of the interplay between the Rab GTPases and innate immunity will help develop novel therapeutics against microbial infections and chronic inflammations.

DRD1 downregulation contributes to mechanical stretch-induced lung endothelial barrier dysfunction

Rationale: The lung-protective effects of dopamine and its role in the pathology of ventilator-induced lung injury (VILI) are emerging. However, the underlying mechanisms are still largely unknown.

Objective: To investigate the contribution of dopamine receptor dysregulation in the pathogenesis of VILI and therapeutic potential of dopamine D1 receptor (DRD1) agonist in VILI.

Methods: The role of dopamine receptors in mechanical stretch-induced endothelial barrier dysfunction and lung injury was studied in DRD1 knockout mice, in isolated mouse lung vascular endothelial cells (MLVECs), and in lung samples from patients who underwent pulmonary lobectomy with mechanical ventilation for different time periods.

Measurements and Main Results: DRD1 was downregulated in both surgical patients and mice exposed to mechanical ventilation. Prophylactic administration of dopamine or DRD1 agonist attenuated mechanical stretch-induced lung endothelial barrier dysfunction and lung injury. By contrast, pulmonary knockdown or global knockout of DRD1 exacerbated these effects. Prophylactic administration of dopamine attenuated mechanical stretch-induced α-tubulin deacetylation and subsequent endothelial hyperpermeability through DRD1 signaling. We identified that cyclic stretch-induced glycogen-synthase-kinase-3β activation led to phosphorylation and activation of histone deacetylase 6 (HDAC6), which resulted in deacetylation of α-tubulin. Upon activation, DRD1 signaling attenuated mechanical stretch-induced α-tubulin deacetylation and subsequent lung endothelial barrier dysfunction through cAMP/exchange protein activated by cAMP (EPAC)-mediated inactivation of HDAC6.

Conclusions: This work identifies a novel protective role for DRD1 against mechanical stretch-induced lung endothelial barrier dysfunction and lung injury. Further study of the mechanisms involving DRD1 in the regulation of microtubule stability and interference with DRD1/cAMP/EPAC/HDAC6 signaling may provide insight into therapeutic approaches for VILI.

pH-responsive DNA nanomicelles for chemo-gene synergetic therapy of anaplastic large cell lymphoma

Chemo-gene therapy is an emerging synergetic modality for the treatment of cancers. Herein, we developed pH-responsive multifunctional DNA nanomicelles (DNMs) as delivery vehicles for controllable release of doxorubicin (Dox) and anaplastic lymphoma kinase (ALK)-specific siRNA for the chemo-gene synergetic therapy of anaplastic large cell lymphoma (ALCL).

Methods: DNMs were synthesized by performing in situ rolling circle amplification (RCA) on the amphiphilic primer-polylactide (PLA) micelles, followed by functionalization of pH-responsive triplex DNA via complementary base pairing. The anticancer drug Dox and ALK-specific siRNA were co-loaded to construct Dox/siRNA/DNMs for chemo-gene synergetic cancer therapy. When exposed to the acidic microenvironment (pH below 5.0), C-G·C⁺ triplex structures were formed, leading to the release of Dox and siRNA for gene silencing to enhance the chemosensitivity in ALCL K299 cells. The chemo-gene synergetic anticancer effect of Dox/siRNA/DNMs on ALCL was evaluated in vitro and in vivo.

Results: The pH-responsive DNMs exhibited good monodispersity at different pH values, good biocompatibility, high drug loading capacity, and excellent stability even in the human serum. With the simultaneous release of anticancer drug Dox and ALK-specific siRNA in response to pH in the tumor microenvironment, the Dox/siRNA/DNMs demonstrated significantly higher treatment efficacy for ALCL compared with chemotherapy alone, because the silencing of ALK gene expression mediated by siRNA increased the chemosensitivity of ALCL cells. From the pathological analysis of tumor tissue, the Dox/siRNA/DNMs exhibited the superiority in inhibiting tumor growth, low toxic side effects and good biosafety.

Conclusion: DNMs co-loaded with Dox and ALK-specific siRNA exhibited significantly enhanced apoptosis of ALCL K299 cells in vitro and effectively inhibited tumor growth in vivo without obvious toxicity, providing a potential strategy in the development of nanomedicines for synergetic cancer therapy.

Autophagy Modulated by Inorganic Nanomaterials

With the rapid development of nanotechnology, inorganic nanomaterials (NMs) have been widely applied in modern society. As human exposure to inorganic NMs is inevitable, comprehensive assessment of the safety of inorganic NMs is required. It is well known that autophagy plays dual roles in cell survival and cell death. Moreover, inorganic NMs have been proven to induce autophagy perturbation in cells. Therefore, an in-depth understanding of inorganic NMs-modulated autophagy is required for the safety assessment of inorganic NMs. This review presents an overview of a set of inorganic NMs, consisting of iron oxide NMs, silver NMs, gold NMs, carbon-based NMs, silica NMs, quantum dots, rare earth oxide NMs, zinc oxide NMs, alumina NMs, and titanium dioxide NMs, as well as how each modulates autophagy. This review emphasizes the potential mechanisms underlying NMs-induced autophagy perturbation, as well as the role of autophagy perturbation in cell fate determination. Furthermore, we also briefly review the potential roles of inorganic NMs-modulated autophagy in diagnosis and treatment of disease.

Ruscogenin alleviates LPS-induced pulmonary endothelial cell apoptosis by suppressing TLR4 signaling

Acute lung injury (ALI) or its most advanced form, acute respiratory distress syndrome (ARDS) is a severe inflammatory pulmonary process triggered by varieties of pathophysiological factors, among which apoptosis of pulmonary endothelial cells plays a critical role in the progression of ALI/ARDS. Ruscogenin (RUS) has been found to exert significant protective effect on ALI induced by lipopolysaccharides (LPS), but there is little information about its role in LPS-induced pulmonary endothelial cell apoptosis. The aim of the present study was to investigate the underlying mechanism in which RUS attenuates LPS-induced pulmonary endothelial cell apoptosis. Mice were challenged with LPS (5 mg/kg) by intratracheal instillation for 24 h to induce apoptosis of pulmonary endothelial cells in model group. RUS (three doses: 0.1, 0.3, and 1 mg/kg) was administrated orally 1 h prior to LPS challenge. The results showed that RUS could attenuate LPS-induced lung injury and pulmonary endothelial apoptosis significantly. And we observed that RUS inhibited the activation of TLR4/MYD88/NF-κB pathway in pulmonary endothelium after LPS treatment. In murine lung vascular endothelial cells (MLECs) we further confirmed that RUS (1 μmol/L) markedly ameliorated MLECs apoptosis by suppressing TLR4 signaling. By using TLR4 knockout mice we found that TLR4 was essential for the RUS-mediated eff ;ect on LPS-stimulated pulmonary endothelial apoptosis. Collectively, our results indicate that RUS plays a protective role against LPS-induced endothelial cell apoptosis via regulating TLR4 signaling, and may be a promising agent in the management of ALI.

FoxO3a depletion accelerates cutaneous wound healing by regulating epithelial‑mesenchymal transition through β‑catenin activation

The hysteresis of keratinocyte (KC) re-epithelialization is an important factor resulting in chronic wounds; however, the molecular mechanisms involved in this cellular response remain yet to be completely elucidated. The present study demonstrated the function of transcription factor Forkhead box O3a (FoxO3a) in KC growth and migration functional effects, resulting in restrained KC re-epithelialization during wound healing. In chronic wound tissue samples, the expression of FoxO3a was significantly increased when compared with the acute wound healing group (P<0.01). Overexpressing FoxO3a significantly inhibited, whereas silencing endogenous FoxO3a enhanced, the growth and migration of HaCaT cells in vitro. Further investigation revealed that FoxO3a negatively regulated matrix metalloproteinases 1 and 9, and increased the expression of tissue inhibitor of metalloproteinase 1. In addition, the upregulation of FoxO3a retarded, whereas the downregulation of FoxO3a accelerated, transforming growth factor-β1-induced epithelial-mesenchymal transition in HaCaT cells. Mechanistically, the overexpression of FoxO3a inactivated β-catenin signaling and markedly reduced the levels of nuclear β-catenin. These results reveal a novel mechanism of FoxO3a in regulating KC re-epithelialization, and provide novel targets for the prevention and treatment of chronic wounds.

Endosomes and Autophagy: Regulators of Pulmonary Endothelial Cell Homeostasis in Health and Disease

Significance: Alterations in oxidant/antioxidant balance injure pulmonary endothelial cells and are important in the pathogenesis of lung diseases, such as Acute Respiratory Distress Syndrome (ARDS), ischemia/reperfusion injury, pulmonary arterial hypertension (PAH), and emphysema. Recent Advances: The endosomal and autophagic pathways regulate cell homeostasis. Both pathways support recycling or degradation of macromolecules or organelles, targeted to endosomes or lysosomes, respectively. Thus, both processes promote cell survival. However, with environmental stress or injury, imbalance in endosomal and autophagic pathways may enhance macromolecular or organelle degradation, diminish biosynthetic processes, and cause cell death. Critical Issues: While the role of autophagy in cellular homeostasis in pulmonary disease has been investigated, the role of the endosome in the lung vasculature is less known. Furthermore, autophagy can either decrease or exacerbate endothelial injury, depending upon inciting insult and disease process. Future Directions: Diseases affecting the pulmonary endothelium, such as emphysema, ARDS, and PAH, are linked to altered endosomal or autophagic processing, leading to enhanced degradation of macromolecules and potential cell death. Efforts to target this imbalance have yielded limited success as treatments for lung injuries, which may be due to the complexity of both processes. It is possible that endosomal trafficking proteins, such as Rab GTPases and late endosomal/lysosomal adaptor, MAPK and MTOR activator 1, may be novel therapeutic targets. While endocytosis or autophagy have been linked to improved function of the pulmonary endothelium in vitro and in vivo, further studies are needed to identify targets for modulating cellular homeostasis in the lung.

FAT1 inhibits the proliferation and metastasis of cervical cancer cells by binding β-catenin

FAT1 is a mutant gene found frequently in human cervical cancer (CC), but its expression and relevance in CC proliferation, invasion, and migration are still unknown. We aimed to explore the role and novel mechanism of FAT1 in CC progression. The expression of FAT1 in CC and adjacent normal tissues was analysed, and we investigated the proliferation, migration, and invasion of HeLa and C33A cells treated with wild-type FAT1 plasmid or FAT1 siRNA. Meanwhile, we evaluated the effect of FAT1 on the epithelial-mesenchymal transition (EMT) and the β-catenin-mediated transcription of target genes. Here, we showed that FAT1 expression was significantly lower in CC tissues than in adjacent tissues. FAT1 overexpression significantly dysregulated CC cell proliferation, invasion, and migration, whereas FAT1 knockdown had the opposite effect. FAT1 overexpression promoted the expression of phosphorylated β-catenin and E-cadherin protein and inhibited the expression of vimentin, TWIST, and several downstream targets of β-catenin, namely, c-MYC, TCF-4 and MMP14. In contrast, FAT1 silencing notably increased the expression c-MYC, TCF-4, and MMP14 and promoted the EMT in HeLa and C33A cells. Endogenous and exogenous FAT1 was confirmed to interact with β-catenin, and the overexpression of β-catenin could partially block the effect of FAT1 on the proliferation, migration, and invasion of HeLa and C33A cells. Conclusion: FAT1 acts as a tumor suppressor by inhibiting β-catenin-mediated transcription and might be used as a novel anti-metastatic agent in targeted CC therapy.

SNRPB promotes the tumorigenic potential of NSCLC in part by regulating RAB26

SNRPB is a core component of spliceosome and plays a major role in regulating alternative splicing of the pre-mRNA. However, little is known about its role in cancer to date. In this study, we observe that SNRPB is overexpressed in NSCLC and correlated with poor prognosis in patients with NSCLC. We demonstrate that SNRPB promotes NSCLC tumorigenesis both in vitro and in vivo. Mechanistically, we reveal that RAB26 is a critical target of SNRPB. Suppression of SNRPB leads to retention of intron seven in the RAB26 mRNA and reduced RAB26 mRNA through activation of nonsense-mediated RNA decay (NMD). Moreover, forced expression of RAB26 partially restores the decreased tumorigenicity in NSCLC cells with SNRPB depletion. Our study unveils a novel role of SNRPB in facilitating NSCLC tumorigenesis via regulation of RAB26 expression and proposes that the SNRPB/RAB26 pathway may offer a therapeutic vulnerability in NSCLC.

A minimalist's approach for DNA nanoconstructions

Structural DNA nanotechnology takes DNA, a biopolymer, far beyond being the molecule that stores and transmits genetic information in biological systems. DNA has been employed as building blocks for the assembly of designed, nanoscaled, supramolecular DNA architectures for applications in biophysics, structure determination, synthetic biology, diagnostics, and drug delivery. Herein, we review a symmetric approach of tile-based DNA self-assembly. This approach allows the construction of DNA nanostructures from minimal numbers of different types of DNA strands based on sequence and structural symmetries. Some examples of the applications of this approach in siRNA delivery are discussed as well.

Endothelial Cell Inflammation and Barriers Are Regulated by the Rab26-Mediated Balance between β2-AR and TLR4 in Pulmonary Microvessel Endothelial Cells

Rab26 GTPase modulates the trafficking of cell surface receptors, such as G protein-coupled receptors including α2-adrenergic receptors in some cell types. However, the effect of Rab26 on β2-adrenergic receptor (β2-AR) trafficking or/and Toll-like receptor 4 (TLR4) expression in human pulmonary microvascular endothelial cells (HPMECs) is still unclear. Here, we investigated the role of Rab26 in regulating the expression of β2-ARs and TLR4 in HPMECs and the effect of these receptors' imbalance on endothelial cell barrier function. The results showed that there was unbalance expression in these receptors, where β2-AR expression was remarkably reduced, and TLR4 was increased on the cell membrane after lipopolysaccharide (LPS) treatment. Furthermore, we found that Rab26 overexpression not only upregulated β2-ARs but also downregulated TLR4 expression on the cell membrane. Subsequently, the TLR4-related inflammatory response was greatly attenuated, and the hyperpermeability of HPMECs also was partially relived. Taken together, these data suggest that basal Rab26 maintains the balance between β2-ARs and TLR4 on the cell surface, and it might be a potential therapeutic target for diseases involving endothelial barrier dysfunction.

Targeted Delivery of Rab26 siRNA with Precisely Tailored DNA Prism for Lung Cancer Therapy

Programmable DNA nanostructures are a new class of biocompatible, nontoxic nanomaterials. Nevertheless, their application in the field of biomedical research is still in its infancy, especially as drug delivery vehicles for gene therapy. In this study, a GTPase Rab26 was investigated as a new potential therapeutic target using a precisely tailored DNA nanoprism for targeted lung cancer therapy. Specifically, a DNA nanoprism platform with tunable targeting and siRNA loading capability is designed and synthesized. The as-prepared DNA prisms were decorated with two functional units: a Rab26 siRNA as the drug and MUC-1 aptamers as a targeting moiety for non-small cell lung cancer. The number and position of both siRNA and MUC-1 aptamers can be readily tuned by switching two short, single-stranded DNA. Native polyacrylamide gel electrophoresis (PAGE) and dynamic light scattering technique (DLS) demonstrate that all nanoprisms with different functionalities are self-assembled with high yield. It is also found that the cellular uptake of DNA prisms is proportional to the aptamer number on each nanoprism, and the as-prepared DNA nanoprism show excellent anti-cancer activities and targeting capability. This study suggests that by careful design, self-assembled DNA nanostructures are highly promising, customizable, multifunctional nanoplatforms for potential biomedical applications, such as personalized precision therapy.

"Trojan Horse" DNA Nanostructure for Personalized Theranostics: Can It Knock on the Door of Preclinical Practice?

Nanotheranostics, combing diagnostic and therapeutic components in an all-in-one nanomaterial, possess exciting potentials for precision nanomedicine. However, a major obstacle for current nanotheranostics to enter preclinical and/or clinical trials is the intrinsic toxicities of these nanomaterials. As an emerging biomaterial, the bioinspired DNA nanostructure shows advantages for constructing better nanotheranostics due to its excellent features, including native biocompatibility, full programmability, and ready accessibility. In this feature article, we highlight recent advances in the design of DNA-nanostructure-based diagnostics and/or therapeutics capable of specifically responding to biological stimuli in a dynamic way, with a particular focus on the design mechanism, responsive performance, and potential for preclinical and/or clinical trials in personalized theranostics.

RAB26-dependent autophagy protects adherens junctional integrity in acute lung injury

Microvascular barrier dysfunction is the central pathophysiological feature of acute lung injury (ALI). RAB26 is a newly identified small GTPase involved in the regulation of endothelial cell (EC) permeability. However, the mechanism behind this protection has not been clearly elucidated. Here we found that RAB26 promoted the integrity of adherens junctions (AJs) in a macroautophagy/autophagy-dependent manner in ALI. RAB26 is frequently downregulated in mouse lungs after LPS treatment. Mice lacking Rab26 exhibited phosphorylated SRC expression and increased CDH5/VE-cadherin phosphorylation, leading to AJ destruction. rab26-null mice showed further aggravation of the effects of endotoxin insult on lung vascular permeability and water content. Depletion of RAB26 resulted in upregulation of phosphorylated SRC, enhancement of CDH5 phosphorylation, and aggravation of CDH5 internalization, thereby weakening AJ integrity and endothelial barrier function in human pulmonary microvascular endothelial cells (HPMECs). RAB26 overexpression caused active interaction between SRC and the autophagy marker LC3-II and promoted degradation of phosphorylated SRC. Furthermore, RAB26 was involved in a direct and activation-dependent manner in autophagy induction through interaction with ATG16L1 in its GTP-bound form. These findings demonstrate that RAB26 exerts a protective effect on endothelial cell (EC) permeability, which is in part dependent on autophagic targeting of active SRC, and the resultant CDH5 dephosphorylation maintains AJ stabilization. Thus, RAB26-mediated autophagic targeting of phosphorylated SRC can maintain barrier integrity when flux through the RAB26-SRC pathway is protected. These findings suggest that activation of RAB26-SRC signaling provides a new therapeutic opportunity to prevent vascular leakage in ALI.

ABBREVIATIONS

AJs: adherens junctions; ALI: acute lung injury; ARDS: acute respiratory distress syndrome; ATG5: autophagy related 5; ATG12: autophagy related 12; ATG 16L1: autophagy related 16 like; 1 BALF: bronchoalveolar lavage fluidCQ: chloroquine; Ctrl: control; EC: endothelial cell; GFP: green fluorescent protein; HA-tagged; RAB26^WT: HA-tagged wild-type; RAB26  HA-tagged; RAB26^QL: HA-tagged; RAB26^Q123LHA-tagged; RAB26^NI: HA-tagged; RAB26^N177IHPMECs: human pulmonary microvascular endothelial cells; H&E: hematoxylin & eosin; IgG: immunoglobulin; GIF: immunofluorescence; IP: immunoprecipitationi;. p.: intraperitoneal; LPS: lipopolysaccharide; PBS: phosphate-buffered salinesi; RNA: small interfering;RNASQSTM1/p62, sequestosome; 1TBS: Tris-buffered saline; VEGF: vascular endothelial growth factor; WB: western blot; WT: wild-type.

DNA nanotriangle-scaffolded activatable aptamer probe with ultralow background and robust stability for cancer theranostics

Activatable aptamers have emerged as promising molecular tools for cancer theranostics, but reported monovalent activatable aptamer probes remain problematic due to their unsatisfactory affinity and poor stability. To address this problem, we designed a novel theranostic strategy of DNA nanotriangle-scaffolded multivalent split activatable aptamer probe (NTri-SAAP), which combines advantages of programmable self-assembly, multivalent effect and target-activatable architecture.

Methods: NTri-SAAP was assembled by conjugating multiple split activatable aptamer probes (SAAPs) on a planar DNA nanotriangle scaffold (NTri). Leukemia CCRF-CEM cell line was used as the model to investigate its detection, imaging and therapeutic effect both in vitro and in vivo. Binding affinity and stability were evaluated using flow cytometry and nuclease resistance assays.

Results: In the free state, NTri-SAAP was stable with quenched signals and loaded doxorubicin, while upon binding to target cells, it underwent a conformation change with fluorescence activation and drug release after internalization. Compared to monovalent SAAP, NTri-SAAP displayed greatly-improved target binding affinity, ultralow nonspecific background and robust stability in harsh conditions, thus affording contrast-enhanced tumor imaging within an extended time window of 8 h. Additionally, NTri-SAAP increased doxorubicin loading capacity by ~5 times, which further realized a high anti-tumor efficacy in vivo with 81.95% inhibition but no obvious body weight loss.

Conclusion: These results strongly suggest that the biocompatible NTri-SAAP strategy would provide a promising platform for precise and high-quality theranostics.