Free-standing homochiral 2D monolayers by exfoliation of molecular crystals.

Two-dimensional materials with monolayer thickness and extreme aspect ratios are sought for their high surface areas and unusual physicochemical properties1. Liquid exfoliation is a straightforward and scalable means of accessing such materials2, but has been restricted to sheets maintained by strong covalent, coordination or ionic interactions3-10. The exfoliation of molecular crystals, in which repeat units are held together by weak non-covalent bonding, could generate a greatly expanded range of two-dimensional crystalline materials with diverse surfaces and structural features. However, at first sight, these weak forces would seem incapable of supporting such intrinsically fragile morphologies. Against this expectation, we show here that crystals composed of discrete supramolecular coordination complexes can be exfoliated by sonication to give free-standing monolayers approximately 2.3 nanometres thick with aspect ratios up to approximately 2,500:1, sustained purely by apolar intermolecular interactions. These nanosheets are characterized by atomic force microscopy and high-resolution transmission electron microscopy, confirming their crystallinity. The monolayers possess complex chiral surfaces derived partly from individual supramolecular coordination complex components but also from interactions with neighbours. In this respect, they represent a distinct type of material in which molecular components are all equally exposed to their environment, as if in solution, yet with properties arising from cooperation between molecules, because of crystallinity. This unusual nature is reflected in the molecular recognition properties of the materials, which bind carbohydrates with strongly enhanced enantiodiscrimination relative to individual molecules or bulk three-dimensional crystals.

Dual-ROS-scavenging and dual-lingering nanozyme-based eye drops alleviate dry eye disease.

Efficiently removing excess reactive oxygen species (ROS) generated by various factors on the ocular surface is a promising strategy for preventing the development of dry eye disease (DED). The currently available eye drops for DED treatment are palliative, short-lived and frequently administered due to the short precorneal residence time. Here, we developed nanozyme-based eye drops for DED by exploiting borate-mediated dynamic covalent complexation between n-FeZIF-8 nanozymes (n-Z(Fe)) and poly(vinyl alcohol) (PVA) to overcome these problems. The resultant formulation (PBnZ), which has dual-ROS scavenging abilities and prolonged corneal retention can effectively reduce oxidative stress, thereby providing an excellent preventive effect to alleviate DED. In vitro and in vivo experiments revealed that PBnZ could eliminate excess ROS through both its multienzyme-like activity and the ROS-scavenging activity of borate bonds. The positively charged nanozyme-based eye drops displayed a longer precorneal residence time due to physical adhesion and the dynamic borate bonds between phenyboronic acid and PVA or o-diol with mucin. The in vivo results showed that eye drops could effectively alleviate DED. These dual-function PBnZ nanozyme-based eye drops can provide insights into the development of novel treatment strategies for DED and other ROS-mediated inflammatory diseases and a rationale for the application of nanomaterials in clinical settings.

Truncation of Tau selectively facilitates its pathological activities.

Neurofibrillary tangles of abnormally hyperphosphorylated Tau are a hallmark of Alzheimer's disease (AD) and related tauopathies. Tau is truncated at multiple sites by various proteases in AD brain. Although many studies have reported the effect of truncation on the aggregation of Tau, these studies mostly employed highly artificial conditions, using heparin sulfate or arachidonic acid to induce aggregation. Here, we report for the first time the pathological activities of various truncations of Tau, including site-specific phosphorylation, self-aggregation, binding to hyperphosphorylated and oligomeric Tau isolated from AD brain tissue (AD O-Tau), and aggregation seeded by AD O-Tau. We found that deletion of the first 150 or 230 amino acids (aa) enhanced Tau's site-specific phosphorylation, self-aggregation, and binding to AD O-Tau and aggregation seeded by AD O-Tau, but deletion of the first 50 aa did not produce a significant effect. Deletion of the last 50 aa was found to modulate Tau's site-specific phosphorylation, promote its self-aggregation, and cause it to be captured by and aggregation seeded by AD O-Tau, whereas deletion of the last 20 aa had no such effects. Among the truncated Taus, Tau151-391 showed the highest pathological activities. AD O-Tau induced aggregation of Tau151-391in vitro and in cultured cells. These findings suggest that the first 150 aa and the last 50 aa protect Tau from pathological characteristics and that their deletions facilitate pathological activities. Thus, inhibition of Tau truncation may represent a potential therapeutic approach to suppress Tau pathology in AD and related tauopathies.

Tau modulates Schwann cell proliferation, migration and differentiation following peripheral nerve injury.

Tau protein (encoded by the gene microtubule-associated protein tau, Mapt) is essential for the assembly and stability of microtubule and the functional maintenance of the nervous system. Tau is highly abundant in neurons and is detectable in astrocytes and oligodendrocytes. However, whether tau is present in Schwann cells, the unique glial cells in the peripheral nervous system, is unclear. Here, we investigated the presence of tau and its coding mRNA, Mapt, in cultured Schwann cells and find that tau is present in these cells. Gene silencing of Mapt promoted Schwann cell proliferation and inhibited Schwann cell migration and differentiation. In vivo application of Mapt siRNA suppressed the migration of Schwann cells after sciatic nerve injury. Consistent with this, Mapt-knockout mice showed elevated proliferation and reduced migration of Schwann cells. Rats injected with Mapt siRNA and Mapt-knockout mice also exhibited impaired myelin and lipid debris clearance. The expression and distribution of the cytoskeleton proteins α-tubulin and F-actin were also disrupted in these animals. These findings demonstrate the existence and biological effects of tau in Schwann cells, and expand our understanding of the function of tau in the nervous system.

Celastrol-based nanomedicine promotes corneal allograft survival.

Effectively promoting corneal allograft survival remains a challenge in corneal transplantation. The emerging therapeutic agents with high pharmacological activities and their appropriate administration routes provide attractive solutions. In the present study, a celastrol-loaded positive nanomedicine (CPNM) was developed to enhance corneal penetration and to promote corneal allograft survival. The in vitro, in vivo and ex vivo results demonstrated the good performance of CPNM prolonging the retention time on ocular surface and opening the tight junction in cornea, which resulted in enhanced corneal permeability of celastrol. Both in vitro and in vivo results demonstrated that celastrol inhibited the recruitment of M1 macrophage and the expression of TLR4 in corneal allografts through the TLR4/MyD88/NF-κB pathway, thereby significantly decreasing secretion of multiple pro-inflammatory cytokines to promote corneal allograft survival. This is the first celastrol-based topical instillation against corneal allograft rejection to provide treatment more potent than conventional eye drops for ocular anterior segment diseases.

Metal-Organic Cages with Missing Linker Defects.

We present here the controlled synthesis of defective coordination cages by employing steric hindrance of organic linkers to manipulate coordination modes of the assembled metal ions. Three chiral 1,1'-bi-2-naphthol (BINOL) derived bis-tridentate ligands L1 -L3 with pyridine-2,6-dicarboxamides (pcam) chelating moieties are therefore designed and synthesized, among which L3 has a smaller steric hindrance on the coordinating sites relative to the other two linkers. Complexes of L1 and L2 with lanthanides afford the irregular Ln8 (L1 )10 hexahedra with two missing edges and Ln4 (L2 )5 tetrahedra with one missing edge, respectively, both of which contain a 1:1 mixture of Ln(pcam)2 and Ln(pcam)3 . In contrast, complex of L3 produces the regular twisted Ln6 (L3 )9 trigonal prisms without missing edges that contain only Ln(pcam)3 vertices. The defective cage has more freedom to adjust its structural conformation, affording adaptable cavity to accommodate a range of guest molecules with sizes comparable or much larger than the cavity portals.

Highly Stable Zr(IV)-Based Metal-Organic Frameworks with Chiral Phosphoric Acids for Catalytic Asymmetric Tandem Reactions.

Heterogeneous Brønsted acid catalysts featuring high porosity, crystallinity, and stability have been of great interest for both fundamental studies and practical applications, but synthetically, they still face a formidable challenge. Here, we illustrated a ligand design strategy for directly installing chiral phosphoric acid catalysts into highly stable Zr-MOFs by sterically protecting them from coordinating with metal ions. A pair of chiral porous Zr(IV)-MOFs with the framework formula [Zr6O4(OH)8(H2O)4(L)2] were prepared from enantiopure 4,4',6,6'-tetra(benzoate) and -tetra(2-naphthoate) ligands of 1,1'-spirobiindane-7,7'-phosphoric acid. They share the same topological structure but differ in channel sizes, and both of them demonstrate excellent tolerance toward water, acid and base. Significantly enhanced Brønsted acidity was observed for the phosphoric acids that are uniformly distributed within the frameworks in comparison with the nonimmobilized acids. This not only facilitates the catalysis of asymmetric two-component tandem acetalization, Friedel-Crafts, and iso-Pictet-Spengler reactions but also promotes the catalysis of asymmetric three-component tandem deacetalization-acetalization and Friedel-Crafts reactions benefiting from the synergy with exposed Lewis acidic Zr(IV) sites. The enantioselectivities are comparable or favorable compared to those obtained from the corresponding homogeneous systems. The features of high reactivity, selectivity, stability, and recyclability for Zr(IV)-MOFs make them hold promise as a new type of heterogeneous acid catalyst for the eco-friendly synthesis of fine chemicals.

Supramolecular Coordination Cages for Asymmetric Catalysis.

Inspired by the high efficiency and specificity of enzymes in living systems, the development of artificial catalysts intrinsic to the key features of enzyme has emerged as an active field. Recent advances in supramolecular chemistry have shown that supramolecular coordination cages, built from non-covalent coordination bonds, offer a diverse platform for enzyme mimics. Their inherent confined cavity, analogous to the binding pocket of an enzyme, and the facile tunability of building blocks are essential for substrate recognition, transition-state stabilization, and product release. In particular, the combination of chirality with supramolecular coordination cages will undoubtedly create an asymmetric microenvironment for promoting enantioselective transformation, thus providing not only a way to make synthetically useful asymmetric catalysts, but also a model to gain a better understanding for the fundamental principles of enzymatic catalysis in a chiral environment. The focus here is on recent progress of supramolecular coordination cages for asymmetric catalysis, and based on how supramolecular coordination cages function as reaction vessels, three approaches have been demonstrated. The aim of this review is to offer researchers general guidance and insight into the rational design of sophisticated cage containers for asymmetric catalysis.

O-GlcNAcylation modulates PKA-CREB signaling in a manner specific to PKA catalytic subunit isoforms.

O-GlcNAcylation is a post-translational modification of proteins. Protein kinase A (PKA)-cAMP response element binding protein (CREB) signaling plays critical roles in multiple biological processes. Isoforms α and ß of PKA catalytic subunit (PKAc) and CREB are modified by O-GlcNAcylation. In the present study, we determined the role of O-GlcNAcylation in PKAc isoform-specific CREB signaling. We found that up-regulation of O-GlcNAcylation enhanced CREB phosphorylation, but suppressed CREB expression in exogenous PKAc isoform-unspecific manner. PKAc isoforms affected exogenous expression of OGT or OGA and protein O-GlcNAcylation differently. Up-regulation of O-GlcNAcylation did not significantly affect net PKAcα-CREB signaling, but enhanced PKAcß-CREB signaling. The role of O-GlcNAcylation in PKA-CREB signaling was desensitized by insulin treatment. This study suggests a role of O-GlcNAcylation in PKA-CREB signaling by affecting phosphorylation of CREB in a PKAc isoform-specific manner.

Guidance receptor promotes the asymmetric distribution of exocyst and recycling endosome during collective cell migration.

During collective migration, guidance receptors signal downstream to result in a polarized distribution of molecules, including cytoskeletal regulators and guidance receptors themselves, in response to an extracellular gradient of chemotactic factors. However, the underlying mechanism of asymmetry generation in the context of the migration of a group of cells is not well understood. Using border cells in the Drosophila ovary as a model system for collective migration, we found that the receptor tyrosine kinase (RTK) PDGF/VEGF receptor (PVR) is required for a polarized distribution of recycling endosome and exocyst in the leading cells of the border cell cluster. Interestingly, PVR signaled through the small GTPase Rac to positively affect the levels of Rab11-labeled recycling endosomes, probably in an F-actin-dependent manner. Conversely, the exocyst complex component Sec3 was required for the asymmetric localization of RTK activity and F-actin, similar to that previously reported for the function of Rab11. Together, these results suggested a positive-feedback loop in border cells, in which RTKs such as PVR act to induce a higher level of vesicle recycling and tethering activity in the leading cells, which in turn enables RTK activity to be distributed in a more polarized fashion at the front. We also provided evidence that E-cadherin, the major adhesion molecule for border cell migration, is a specific cargo in the Rab11-labeled recycling endosomes and that Sec3 is required for the delivery of the E-cadherin-containing vesicles to the membrane.

MicroRNA-148a Suppresses Invasion and Metastasis of Human Non-Small-Cell Lung Cancer.

BACKGROUND/AIMS: microRNAs (miRNAs) are noncoding RNAs that regulate multiple targets through either the degradation of mRNAs or the inhibition of protein translation, thereby altering several functions simultaneously. Growing evidence indicates that miRNAs are involved in carcinogenesis and tumor progression in non-small-cell lung cancer (NSCLC). METHODS: In this study, the mRNA expression levels of miR-148a were examined in NSCLC cell lines and patient specimens using quantitative reverse transcription-PCR. The functions of miR-148a in migration/invasion and lung metastasis formation were determined by using transwell and tail vein injection assays, respectively. RESULTS: We demonstrated that miR-148a was down-regulated in NSCLC metastatic samples, and its expression was suppressed in NSCLC compared with the corresponding nonmalignant lung tissues. Clinical analysis indicated that miR-148a expression was lower in NSCLC patients compared with nonmalignant lung tissues . Decreased miR-148a was significantly associated with tumor node metastasis stage and lymph node metastasis. Furthermore, functional assays showed that miR-148a expression suppressed NSCLC cell invasive and migratory abilities in vitro and suppressed cancer metastasis in vivo, while inhibition of miR-148a enhanced NSCLC cell invasion and lung metastasis formation in a mouse model. CONCLUSIONS: Evidence from this study demonstrated that miR-148a exerts tumor-suppressive effects in NSCLC and suggests a new therapeutic option for NSCLC.

AIP1 acts with cofilin to control actin dynamics during epithelial morphogenesis.

During epithelial morphogenesis, cells not only maintain tight adhesion for epithelial integrity but also allow dynamic intercellular movement to take place within cell sheets. How these seemingly opposing processes are coordinated is not well understood. Here, we report that the actin disassembly factors AIP1 and cofilin are required for remodeling of adherens junctions (AJs) during ommatidial precluster formation in Drosophila eye epithelium, a highly stereotyped cell rearrangement process which we describe in detail in our live imaging study. AIP1 is enriched together with F-actin in the apical region of preclusters, whereas cofilin displays a diffuse and uniform localization pattern. Cofilin overexpression completely rescues AJ remodeling defects caused by AIP1 loss of function, and cofilin physically interacts with AIP1. Pharmacological reduction of actin turnover results in similar AJ remodeling defects and decreased turnover of E-cadherin, which also results from AIP1 deficiency, whereas an F-actin-destabilizing drug affects AJ maintenance and epithelial integrity. Together with other data on actin polymerization, our results suggest that AIP1 enhances cofilin-mediated actin disassembly in the apical region of precluster cells to promote remodeling of AJs and thus intercellular movement, but also that robust actin polymerization promotes AJ general adhesion and integrity during the remodeling process.

A cardiomyocyte-specific Wdr1 knockout demonstrates essential functional roles for actin disassembly during myocardial growth and maintenance in mice.

Actin dynamics are critical for muscle development and function, and mutations leading to deregulation of actin dynamics cause various forms of heritable muscle diseases. AIP1 is a major cofactor of the actin depolymerizing factor/cofilin in eukaryotes, promoting actin depolymerizing factor/cofilin-mediated actin disassembly. Its function in vertebrate muscle has been unknown. To investigate functional roles of AIP1 in myocardium, we generated conditional knockout (cKO) mice with cardiomyocyte-specific deletion of Wdr1, the mammalian homolog of yeast AIP1. Wdr1 cKO mice began to die at postnatal day 13 (P13), and none survived past P24. At P12, cKO mice exhibited cardiac hypertrophy and impaired contraction of the left ventricle. Electrocardiography revealed reduced heart rate, abnormal P wave, and abnormal T wave at P10 and prolonged QT interval at P12. Actin filament (F-actin) accumulations began at P10 and became prominent at P12 in the myocardium of cKO mice. Within regions of F-actin accumulation in myofibrils, the sarcomeric components α-actinin and tropomodulin-1 exhibited disrupted patterns, indicating that F-actin accumulations caused by Wdr1 deletion result in disruption of sarcomeric structure. Ectopic cofilin colocalized with F-actin aggregates. In adult mice, Wdr1 deletion resulted in similar but much milder phenotypes of heart hypertrophy, F-actin accumulations within myofibrils, and lethality. Taken together, these results demonstrate that AIP1-regulated actin dynamics play essential roles in heart function in mice.

Dual-specificity tyrosine phosphorylation-regulated kinase 1A promotes the inclusion of amyloid precursor protein exon 7.

Extracellular amyloid plaques made of Amyloid-ß (Aß) derived from amyloid precursor protein (APP) is one of the major neuropathological hallmarks of Alzheimer's disease (AD). There are three major isoforms of APP, APP770, APP751, and APP695 generated by alternative splicing of exons 7 and 8. Exon 7 encodes the Kunitz protease inhibitor (KPI) domain. Its inclusion generates APP isoforms containing KPI, APPKPI+, which is elevated in AD and Down syndrome (DS) brains and associated with increased Aß deposition. Dual-specificity tyrosine phosphorylation-regulated kinase 1A (Dyrk1A) phosphorylates many splicing factors and regulates the alternative splicing of pre-mRNA. It is upregulated in DS and AD brain. However, it is not yet clear whether Dyrk1A could regulate APP alternative splicing. In the present study, we overexpressed or knocked down Dyrk1A in cultured cells and observed that Dyrk1A promoted the inclusion of both APP exons 7 and 8. Moreover, a significant increase in APP exon7 inclusion was also detected in the forebrain and hippocampus of human Dyrk1A transgenic mice - Tg/Dyrk1A. Screening for splicing factors regulated by Dyrk1A revealed that serine/arginine-rich protein 9G8 inhibited APP exon7 inclusion and interacted with APP pre-mRNA. In vitro, expression of exon 7 facilitated APP cleavage. In human Dyrk1A transgenic mice, we also found an increase in Aß production. These findings suggest that Dyrk1A inhibits the splicing factor 9G8 and promotes APP exon 7 inclusion, leading to more APPKPI+ expression and APP cleavage and potentially contributing to Aß production in vivo.

Modification effects of immigration status and comorbidities on associations of heat and heatwave with stroke morbidity.

BACKGROUND: Heat and heatwave have been associated with stroke morbidity, but it is still unclear whether immigrants from different geographic regions and patients with comorbidity are more vulnerable to heat and heatwave. METHODS: Time-stratified case-crossover design combined with generalized additive quasi-Poisson models were used to quantify the relative risks (RRs) of heat and heatwave on first-ever stroke morbidity during 0-7 lag days. Attributable fractions (AFs) were estimated to assess the first-ever stroke morbidity burden due to heat and heatwave. Stratified analyses for sex, age, disease subtypes, resident characteristics, and comorbidity type were performed to identify potential modification effects. RESULTS: Heat and heatwave were associated with first-ever stroke morbidity, with the AF of 2.535% (95% empirical confidence interval (eCI) = 0.748, 4.205) and 2.409% (95% confidence interval (CI) = 1.228, 3.400), respectively. Among northern and southern immigrants, the AF for heat was 2.806% (0.031, 5.069) and 2.798% (0.757, 4.428), respectively, and the AF for heatwave was 2.918% (0.561, 4.618) and 2.387% (1.174, 3.398), respectively, but the effects of both on natives were statistically insignificant. Among patients with hypertension, dyslipidemia, or diabetes, the AF for heat was 3.318% (1.225, 5.007), 4.237% (1.037, 6.770), and 4.860% (1.171, 7.827), respectively, and the AF for heatwave was 2.960% (1.701, 3.993), 2.771% (0.704, 4.308), and 2.652% (0.653, 4.185), respectively. However, the effects of both on patients without comorbidity were statistically insignificant. CONCLUSION: Heat and heatwave are associated with an increased risk of first-ever stroke morbidity among immigrants and those with comorbid hypertension, dyslipidemia, or diabetes, with the effects primarily due to non-native individuals. DATA ACCESS STATEMENT: The author(s) are not authorized to share the data.

Neuronal aerobic glycolysis exacerbates synapse loss in aging mice.

Brain consumes nearly 20% supply of energy from glucose metabolism by oxidative phosphorylation and aerobic glycolysis. Less active state of glycolytic enzymes results in a limited capacity of glycolysis in the neurons of adult brain. Here we identified that Warburg effect is enhanced in hippocampal neurons during aging. As hippocampal neurons age, lactate levels progressively increase. Notably, we observed upregulated protein levels of PFKFB3 in the hippocampus of 20-month-old mice compared to young mice, and this higher PFKFB3 expression correlated with declining memory performance in aging mice. Remarkably, in aging mice, knocking down Pfkfb3 in hippocampal neurons rescued cognitive decline and synapse loss. Conversely, Pfkfb3 overexpression in hippocampal neurons led to cognitive impairment and synapse elimination, associated with heightened glycolysis. In vitro experiments with cultured primary neurons confirmed that Pfkfb3 overexpression increased glycolysis and that glycolytic inhibition could prevent apoptotic competency in neurons. These findings underscore that glycolysis in hippocampal neurons could potentially be targeted as a therapeutic avenue to mitigate cognitive decline and preserve synaptic integrity during aging.

Celastrol alleviates subconjunctival fibrosis induced by silicone implants mimicking glaucoma surgery.

Subconjunctival fibrosis is critical to the outcomes of several ophthalmic conditions or procedures, such as glaucoma filtering surgery. This study aimed to investigate the anti-fibrotic effect of celastrol on subconjunctival fibrosis and to further reveal the underlying mechanisms. We used celastrol-loaded nanomicelles hydrogel hybrid as a sustained-release drug. A rabbit model of subconjunctival fibrosis following silicone implantation was used for in vivo study, and TGF-ß1-induced human pterygium fibroblast (HPF) activation as an in vitro model. The effects of celastrol on inhibiting TGF-ß1-induced migration and proliferation of HPFs were evaluated by scratch wound assay and CCK-8, respectively. Immunofluorescence and western blotting were used to examine the effect of celastrol on the expression of α-SMA, collagen I, fibronectin, and the targets of the Hippo signaling pathway. We found that in vivo celastrol treatment reduced the expression of YAP and TAZ in subconjunctival tissue. Moreover, celastrol alleviated collagen deposition and subconjunctival fibrosis at 8 weeks. No obvious tissue toxicity was observed in the rabbit models. Mechanistically, celastrol significantly inhibited TGF-ß1-induced proliferation and migration of HPFs. Pretreatment of HPFs with celastrol also suppressed the TGF-ß1-induced protein expression of α-SMA, collagen I, fibronectin, TGF-ßRII, phosphorylated Smad2/3, YAP, TAZ, and TEAD1. In conclusion, celastrol effectively prevented subconjunctival fibrosis through inhibiting TGF-ß1/Smad2/3-YAP/TAZ pathway. Celastrol could serve as a promising therapy for subconjunctival fibrosis.

An injectable thermoresponsive-hydrogel for lamellar keratoplasty: In-situ releases celastrol and hampers corneal scars.

Corneal stromal fibrosis is a common cause of visual impairment resulting from corneal injury, inflammation and surgery. Therefore, there is an unmet need for inhibiting corneal stromal fibrosis. However, bioavailability of topical eye drops is very low due to the tear and corneal barriers. In situ delivery offers a unique alternative to improve efficacy and minimize systemic toxicity. Herein, a drug delivery platform based on thermoresponsive injectable hydrogel/nano-micelles composite with in situ drug-controlled release and long-acting features is developed to prevent corneal scarring and reduce corneal stromal fibrosis in lamellar keratoplasty. The in-situ gelation hydrogels enabled direct delivery of celastrol to the corneal stroma. In vivo evaluation with a rabbit anterior lamellar keratoplasty model showed that hydrogel/micelles platform could effectively inhibit corneal stromal fibrosis. This strategy achieves controlled and prolonged release of celastrol in the corneal stroma of rabbit. Following a single corneal interlamellar injection, celastrol effectively alleviated fibrosis via mTORC1 signal promoting autophagy and inhibiting TGF-ß1/Smad2/3 signaling pathway. Overall, this strategy demonstrates promise for the clinical application of celastrol in preventing corneal scarring and reducing corneal stromal fibrosis post-lamellar keratoplasty, highlighting the potential benefits of targeted drug delivery systems in ocular therapeutics.

Dual-Atom Nanozyme Eye Drops Attenuate Inflammation and Break the Vicious Cycle in Dry Eye Disease.

Dry eye disease (DED) is a major ocular pathology worldwide, causing serious ocular discomfort and even visual impairment. The incidence of DED is gradually increasing with the high-frequency use of electronic products. Although inflammation is core cause of the DED vicious cycle, reactive oxygen species (ROS) play a pivotal role in the vicious cycle by regulating inflammation from upstream. Therefore, current therapies merely targeting inflammation show the failure of DED treatment. Here, a novel dual-atom nanozymes (DAN)-based eye drops are developed. The antioxidative DAN is successfully prepared by embedding Fe and Mn bimetallic single-atoms in N-doped carbon material and modifying it with a hydrophilic polymer. The in vitro and in vivo results demonstrate the DAN is endowed with superior biological activity in scavenging excessive ROS, inhibiting NLRP3 inflammasome activation, decreasing proinflammatory cytokines expression, and suppressing cell apoptosis. Consequently, the DAN effectively alleviate ocular inflammation, promote corneal epithelial repair, recover goblet cell density and tear secretion, thus breaking the DED vicious cycle. Our findings open an avenue to make the DAN as an intervention form to DED and ROS-mediated inflammatory diseases.

M2 macrophages promote subconjunctival fibrosis through YAP/TAZ signalling.

PURPOSE: To evaluate the role of M2 macrophages in subconjunctival fibrosis after silicone implantation (SI) and investigate the underlying mechanisms. MATERIALS AND METHODS: A model of subconjunctival fibrosis was established by SI surgery in rabbit eyes. M2 distribution and collagen deposition were evaluated by histopathology. The effects of M2 cells on the migration (using wound-scratch assay) and activation (by immunofluorescence and western blotting) of human Tenon's fibroblasts (HTFs) were investigated. RESULTS: There were more M2 macrophages (CD68+/CD206+ cells) occurring in tissue samples around silicone implant at 2 weeks postoperatively. Dense collagen deposition was observed at 8 weeks after SI. In vitro experiment showed M2 expressed high level of CD206 and transforming growth factor-ß1 (TGF-ß1). The M2-conditioned medium promoted HTFs migration and the synthesis of collagen I and fibronectin. Meanwhile, M2-conditioned medium increased the protein levels of TGF-ß1, TGF-ßR II, p-Smad2/3, yes-associated protein (YAP), and transcriptional coactivator with PDZ-binding motif (TAZ). Verteporfin, a YAP inhibitor, suppressedTGF-ß1/Smad2/3-YAP/TAZ pathway and attenuated M2-induced extracellular matrix deposition by HTFs. CONCLUSIONS: TGF-ß1/Smad2/3-YAP/TAZ signalling may be involved in M2-induced fibrotic activities in HTFs. M2 plays a key role in promoting subconjunctival fibrosis and can serve as an attractive target for anti-fibrotic therapeutics.