NLRP12- and NLRC4-mediated corneal epithelial pyroptosis is driven by GSDMD cleavage accompanied by IL-33 processing in dry eye

Impact of inflammasomes on the ocular surface

PURPOSE OF REVIEW

The ocular surface is prone to inflammation due to exposure to environmental irritants and pathogens. Inflammasomes are intracellular, multiprotein complexes that communicate potentially dangerous signals to the immune system. The identification of inflammasomes in various inflammatory ocular surface conditions can aid in the development of therapeutics to treat these chronic inflammatory conditions.

RECENT FINDINGS

Several inflammasomes have been associated with ocular surface disorders including dry eye disease, keratitis, and allergies. Mechanisms for activation of these inflammasomes with regards to specific disorders have been explored in models to aid in the development of targeted treatments.

SUMMARY

Research efforts continue to characterize the types of inflammasomes and activators of these in inflammatory ocular surface conditions. Various therapies targeting specific inflammasome types or pyroptosis are being tested preclinically to assess effects on decreasing the associated chronic inflammation.

Recent advances in NLRP3 inflammasome in corneal diseases: Preclinical insights and therapeutic implications

NLRP3 inflammasome is a cytosolic multiprotein complex formed in response to exogenous environmental stress and cellular damage. The three major components of the NLRP3 inflammasome are the innate immunoreceptor protein NLRP3, the adapter protein apoptosis-associated speck-like protein containing a C-terminal caspase activation and recruitment domain, and the inflammatory protease enzyme caspase-1. The integrated NLRP3 inflammasome triggers the activation of caspase-1, leading to GSDMD-dependent pyroptosis and facilitating the maturation and release of inflammatory cytokines, namely interleukin (IL)-18 and IL-1β. However, the inflammatory responses mediated by the NLRP3 inflammasome exhibit dual functions in innate immune defense and cellular homeostasis. Aberrant activation of the NLRP3 inflammasome matters in the etiology and pathophysiology of various corneal diseases. Corneal alkali burn can induce pyroptosis, neutrophil infiltration, and corneal angiogenesis via the activation of NLRP3 inflammasome. When various pathogens invade the cornea, NLRP3 inflammasome recognizes pathogen-associated molecular patterns or damage-associated molecular patterns to engage in pro-inflammatory and anti-inflammatory mechanisms. Moreover, chronic inflammation and proinflammatory cascades mediated by the NLRP3 inflammasome contribute to the pathogenesis of diabetic keratopathy. Furthermore, overproduction of reactive oxygen species, mitochondrial dysfunction, and toll-like receptor-mediated activation of nuclear factor kappa B drive the stimulation of NLRP3 inflammasome and participate in the progression of dry eye disease. However, there still exist controversies regarding the regulatory pathways of the NLRP3 inflammasome. In this review, we provide a comprehensive overview of recent advancements in the function of NLRP3 inflammasome in corneal diseases and its regulatory pathways primarily through studies using animal models. Furthermore, we explore prospects for pharmacologically targeting pathways associated with NLRP3.

Heating-driven self-assembled glycyrrhizin nanomicelles loading bisdemethoxycurcumin: Preparation, characterization, and efficacy evaluation on experimental dry eye

In this study, a simple but novel preparation method was developed by heating a mixture of dipotassium glycyrrhizinate (DG) and bisdemethoxycurcumin (BDMC) in aqueous solution, and a DG self-assembled nanomicelles-loading BDMC (named B@DNM) ophthalmic solution was successfully fabricated with this heating-driven process. AutoDock simulation analysis revealed that Pi-Alkyl hydrophobic interactions between BDMC and DG played important role in this self-assembled B@DNM. The optimized B@DNM, with a DG:BDMC mass ratio of 40:1 and heating time of 6 h, had a high encapsulation efficacy of 96.70 ± 0.13 % and particle sizes of 117.50 ± 6.07 nm. The apparent solubility of BDMC in B@DNM was significantly improved from bare BDMC (10.40 ± 0.16 μg/ml to 1405.60 ± 6.78 μg/ml) in artificial tears after 4 h incubation. B@DNM had great storage stability as an aqueous ophthalmic solution. B@DNM showed significantly improved in vitro antioxidant activity. Ex vivo hen's egg test-chorioallantoic membrane assay and long-term in vivo mouse eye tolerance evaluation showed that B@DNM had good ocular safety profiles. B@DNM showed improved in vivo corneal permeation profiles in the mouse eyes. Topical administration of B@DNM achieved a significantly improved efficacy on a mouse model of dry eye disease (DED), including accelerating corneal wound healing, restoring corneal sensitivity, and inhibiting corneal neovascularization. Regulation of the high mobility group box 1 signal pathway was involved in B@DNM's strong therapeutic effects. These findings demonstrate that heating is a simple method to prepare ocular nanoformulation with DG, and B@DNM might be a potential ocular drug for treating DED.

Astaxanthin activated the SLC7A11/GPX4 pathway to inhibit ferroptosis and enhance autophagy, ameliorating dry eye disease

Dry eye disease (DED) is a common eye disease in clinical practice. The crucial pathogenesis of DED is that hyperosmolarity activates oxidative stress signaling pathways in corneal epithelial and immune cells and, thus, produces inflammatory molecules. The complex pathological changes in the dry eye still need to be elucidated to facilitate treatment. In this study, we found that astaxanthin (AST) can protect against DED through the SLC7A11/GPX4 pathway. After treatment with AST, the SLC7A11/GPX4 pathway was positively activated in DED both in vivo and in vitro, accompanied by enhanced autophagy and decreased ferroptosis. In hyperosmolarity-induced DED corneal epithelial cells, AST increased the expression of ferritin to promote iron storage and reduce Fe2+ overload. It increased glutathione (GSH) and GPX4, scavenged reactive oxygen species (ROS) and lipid peroxide, and rescued the mitochondrial structure to prevent ferroptosis. Furthermore, inhibition of ferroptosis by ferrostatin-1 (Fer-1), iron chelator deferoxamine mesylate (DFO), or AST could activate healthy autophagic flux. In addition, in a dry eye mouse model, AST upregulated SLC7A11 and GPX4 and inhibited ferroptosis. To summarize, we found that AST can ameliorate DED by reinforcing the SLC7A11/GPX4 pathway, which mainly affects oxidative stress, autophagy, and ferroptosis processes.

Oridonin ameliorates ocular surface inflammatory responses by inhibiting the NLRP3/caspase-1/GSDMD pyroptosis pathway in dry eye

Chronic inflammation is one of the central drivers in the development of dry eye disease (DED), in which pyroptosis induced by the NLRP3/caspase-1/gasdermin D (GSDMD) pathway plays a key role. This pathway has become a major target for the treatment of a variety of inflammatory disorders. Oridonin (Ori) is a naturally occurring substance with anti-inflammatory properties obtained from Rabdosia rubescens. Whether Ori can exert an anti-inflammatory effect on DED, and its anti-inflammatory mechanism of action, are still unknown. This experiment is intended to investigate the impact of Ori on the hyperosmolarity-induced NLRP3/caspase-1/GSDMD pyroptosis pathway in immortalized human corneal epithelial (HCE-T) cells, as well as its efficacy and mechanism of action on ocular surface injury in DED mice. Our study showed that Ori could inhibit hyperosmotic-induced pyroptosis through the NLRP3/caspase-1/GSDMD pathway in HCE-T cells, and similarly, Ori inhibited the expression of this pathway in DED mice. Moreover, Ori was protective against hyperosmolarity-induced HCE-T cell damage. In addition, we found that the morphology and number of HCE-T cells were altered under culture conditions of various osmolarities. With increasing osmolarity, the proliferation, migration, and healing ability of HCE-T cells decreased significantly, and the expression of N-GSDMD was elevated. In a mouse model of DED, Ori application inhibited the expression of the NLRP3/caspase-1/GSDMD pyroptosis pathway, improved DED signs and injury, decreased corneal sodium fluorescein staining scores, and increased tear volume. Thus, our study suggests that Ori has potential applications for the treatment of DED, provides potential novel therapeutic approaches to treat DED, and provides a theoretical foundation for treating DED using Ori.

Targeting inflammasomes and pyroptosis in retinal diseases-molecular mechanisms and future perspectives

Retinal diseases encompass various conditions associated with sight-threatening immune responses and are leading causes of blindness worldwide. These diseases include age-related macular degeneration, diabetic retinopathy, glaucoma and uveitis. Emerging evidence underscores the vital role of the innate immune response in retinal diseases, beyond the previously emphasized T-cell-driven processes of the adaptive immune system. In particular, pyroptosis, a newly discovered programmed cell death process involving inflammasome formation, has been implicated in the loss of membrane integrity and the release of inflammatory cytokines. Several disease-relevant animal models have provided evidence that the formation of inflammasomes and the induction of pyroptosis in innate immune cells contribute to inflammation in various retinal diseases. In this review article, we summarize current knowledge about the innate immune system and pyroptosis in retinal diseases. We also provide insights into translational targeting approaches, including novel drugs countering pyroptosis, to improve the diagnosis and treatment of retinal diseases.

BMSC Alleviates Dry Eye by Inhibiting the ROS-NLRP3-IL-1β Signaling Axis by Reducing Inflammation Levels

PURPOSE

Bone marrow mesenchymal stem cells (BMSC) have multiple biological functions and are widely involved in regulating inflammatory diseases, tissue repair and regeneration. However, the mechanism of their action in dry eye disease (DED) is currently unclear. The purpose of this study was to investigate the effect of BMSCs in the treatment of dry eye mice and to explore its specific therapeutic mechanism.

METHODS

Mouse corneal epithelial cells (MCECs) were treated with 500 mOsM sodium chloride hypertonic solution to induce a DED cell model. The dry eye animal model was constructed by adding 5 μL 0.2% benzalkonium chloride solution to mouse eyes. Western blotting was used to detect the expression of related proteins, and flow cytometry, enzyme-linked immunosorbent assay (ELISA), terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining, hematoxylin-eosin (HE) staining, and periodic acid schiff (PAS) staining were used to detect cell and eye tissue damage.

RESULTS

The experimental results showed that BMSCs can reduce the levels of reactive oxygen species (ROS) and inflammatory factors in MCECs, promote cell proliferation, inhibit cell apoptosis, improve the integrity of the corneal epithelial layer in vivo, promote an increase in the number of goblet cells, and alleviate DED. Further exploration of the molecular mechanism of BMSCs treatment revealed that BMSCs alleviate the progression of DED by inhibiting the ROS-NLRP3-IL-1β signaling pathway.

CONCLUSION

BMSCs inhibit ROS-NLRP3-IL-1β signaling axis, reducing inflammation levels and alleviating dry eye symptoms. These findings provide new ideas and a basis for the treatment of DED and provide an experimental basis for further research on the application value of BMSCs in alleviating DED.

IL-1β induced down-regulation of miR-146a-5p promoted pyroptosis and apoptosis of corneal epithelial cell in dry eye disease through targeting STAT3

AIM

To elaborate the underlying mechanisms by which IL-1β promote progression of Dry eye disease(DED) through effect on pyroptosis and apoptosis of corneal epithelial cells(CECs).

METHODS

400 mOsM solutions were used to establish the DED model (hCECs- DED). RT-qPCR was performed to measure IL-1β mRNA and miR-146a-5p in CECs. Western blotting was performed to measure STAT3, GSDMD, NLRP3, and Caspase-1 levels. Cell counting kit-8 assay was adopted to check cell viability. Apoptosis was detected by flow cytometry. ELISAs were performed to determine IL-18, IL-33 and LDH. The luciferase test detects targeting relationships.

RESULTS

After treatment with 400 mOsM solution, cell viability decreased and apoptosis increased. Compared with hCECs, IL-1β was increased and miR-146a-5p was decreased in hCECs-DED. At the same time, GSDMD, NLRP3, Caspase-1, IL-18, IL-33 and LDH were significantly higher in hCECs-DED than in hCECs, while IL-1β silencing reversed this effect. In addition, IL-1β negatively regulated miR-146a-5p. MiR-146a-5p mimics eliminated the inhibition of hCECs-DED pyroptosis and apoptosis caused by IL-1β silencing. At the same time, miR-146a-5p reduced STAT3 levels in hCECs.

CONCLUSION

Highly expressed IL-1β promoted pyroptosis and apoptosis of hCECs- DED through downregulated miR-146a-5p and inhibited STAT3.

Prostaglandin E2 may clinically alleviate dry eye disease by inducing Th17 cell differentiation

Dry eye (DE) is a multifactorial ocular surface disease characterised by an imbalance in tear homeostasis. The pathogenesis of DE is complex and related to environmental, immunological (e.g., T helper 17 cells) and other factors. However, the DE disease pathogenesis remains unclear, thereby affecting its clinical treatment. This study aimed to explore the mechanism through which prostaglandin E2 (PGE2) affects DE inflammation by regulating Th17. The DE mouse model was established through subcutaneous injection of scopolamine hydrobromide. The tear secretion test and break-up time (BUT) method were used to detect tear secretion and tear film BUT, respectively. Enzyme-linked immunosorbent assay (ELISA) was used to detect the concentrations of PGE2, interleukin (IL)-17, IL-6 and tumour necrosis factor (TNF-α) in tear fluid and those of PGE2 and IL-17 in the serum. RT-qPCR and western blotting were used to test the mRNA and protein expression levels of IL-17 and retinoid-related orphan receptor-γt (RORγt). PGE2 was highly expressed in the DE mouse model. The mRNA and protein levels of IL-17 and the key Th17 transcription factor RORγt were increased in tissues of the DE mice. Moreover, PGE2 promoted tear secretion, reduced the BUT, increased the IL-17 concentration in tears and increased the Th17 cell proportion in DE, whereas the PGE2 receptor inhibitor AH6809 reversed the effects of PGE2 on tear secretion, BUT, and the Th17 cell proportion in draining lymph node (DLN) cells. Taken together, the study findings indicate that PGE2 could induce DE-related symptoms by promoting Th17 differentiation.

lncRNA Profiling of Exosomes and Its Communication Role in Regulating Silica-Stimulated Macrophage Apoptosis and Fibroblast Activation

Long-term silica particle exposure leads to interstitial pulmonary inflammation and fibrosis, called silicosis. Silica-activated macrophages secrete a wide range of cytokines resulting in persistent inflammation. In addition, silica-stimulated activation of fibroblast is another checkpoint in the progression of silicosis. The pathogenesis after silica exposure is complex, involving intercellular communication and intracellular signaling pathway transduction, which was ignored previously. Exosomes are noteworthy because of their crucial role in intercellular communication by delivering bioactive substances, such as lncRNA. However, the expression profile of exosomal lncRNA in silicosis has not been reported yet. In this study, exosomes were isolated from the peripheral serum of silicosis patients or healthy donors. The exosomal lncRNAs were profiled using high-throughput sequencing technology. Target genes were predicted, and functional annotation was performed using differentially expressed lncRNAs. Eight aberrant expressed exosomal lncRNAs were considered to play a key role in the process of silicosis according to the OPLS-DA. Furthermore, the increased expression of lncRNA MSTRG.43085.16 was testified in vitro. Its target gene PARP1 was critical in regulating apoptosis based on bioinformatics analysis. In addition, the effects of exosomes on macrophage apoptosis and fibroblast activation were checked based on a co-cultured system. Our findings suggested that upregulation of lncRNA MSTRG.43085.16 could regulate silica-induced macrophage apoptosis through elevating PARP1 expression, and promote fibroblast activation, implying that the exosomal lncRNA MSTRG.43085.16 might have potential as a biomarker for the early diagnosis of silicosis.

KCNK5 Regulating Potassium Efflux and Inducing Pyroptosis in Corneal Epithelial Cells Through TNFSF10-Mediated Autophagy in Dry Eye

Purpose

The purpose of this study was to elucidate the involvement of potassium two pore domain channel subfamily K member 5 (KCNK5)-mediated potassium efflux in the pathogenesis of dry eye and to unravel the underlying molecular mechanisms.

Methods

To induce experimental dry eye in adult wild-type C57BL/6 mice, scopolamine was administered via subcutaneous injection, and the mice were subjected to desiccating stress. To create an in vitro model of dry eye, desiccation stress was applied to the human corneal epithelial cell line (HCE-T). Intracellular potassium concentration was quantified using inductively coupled plasma mass spectrometry. Cellular death was assessed through lactate dehydrogenase assays. Gene expression profiling was conducted through both RNA sequencing and quantitative real-time PCR. Protein analysis was carried out through Western blotting and immunofluorescence staining. Assessment of the corneal epithelial defect area was conducted through fluorescein sodium staining. Tear secretion was quantified using the phenol red cotton thread method.

Results

Potassium efflux was observed to further facilitate corneal epithelial pyroptosis. KCNK5 exhibited upregulation in both in vivo and in vitro models of dry eye. The overexpression of KCNK5 was observed to induce potassium efflux and activate the NLR family pyrin domain containing 3 (NLRP3) inflammasome-mediated pyroptosis in vitro. Silencing KCNK5 effectively mitigated pyroptosis in dry eye. Additionally, the overexpression of KCNK5 results in the downregulation of TNF superfamily member 10 (TNFSF10) and subsequent impairment of autophagy. TNFSF10 supplementation could promote autophagy and mitigate pyroptosis in dry eye.

Conclusions

The upregulation of KCNK5 mediates TNFSF10 to impair autophagy and induce pyroptosis in dry eye. Consequently, targeting KCNK5 may represent a novel and promising approach to therapeutic intervention in the management of dry eye.

Prostaglandin E2 promotes Th17 differentiation induces corneal epithelial cell apoptosis and participates in the progression of dry eye

This study is mainly based on T helper type 17 (Th17) cells analysis of the mechanism of prostaglandin E2 (PGE2) promoting the progression of dry eye (DE). Scopolamine and dry environment were used to induce mice DE model. Celecoxib was used to inhibit PGE2. Corneal epithelial cells and CD4+ T cells were used to construct a co-culture system. The osmotic pressure was increased by adding NaCl to simulate DE in vitro. AH6809 and E7046 were used to pre-culture to inhibit EP2/4 in T cells to verify the effect of exogenous PGE2 on Th17 cell differentiation and corneal epithelial cell apoptosis. The function of Th17 cells was analyzed by detecting RORγt and interleukin-17 (IL-17). PGE2 was instilled on the ocular surface to induce DE symptoms of mice. AH6809 and E7046 were used to inhibit EP2/4. The corneal epithelial cell apoptosis was observed by TUNEL. The proportion of Th17 cells in corneal tissue and draining lymph nodes (DLNs) was detected by flow cytometry. In DE mice, the concentration of PGE2 and IL-17 increased in tears, and the proportion of Th17 increased, while inhibition of PGE2 alleviated the symptoms of DE and inhibited Th17 differentiation. Hypertonic environment induces corneal epithelial cells to secrete PGE2. PGE2 promoted the expression of EP2/4 and the differentiation of Th17 cells in vitro. The hypertonic environment promoted PGE2 level and the apoptosis of corneal epithelial cells in the co-culture system. PGE2 alone did not cause corneal epithelial cell apoptosis, while PGE2 promoted apoptosis by promoting Th17. Blocking EP2/4 reduced the induction of Th17 differentiation by PGE2 and the promoted corneal epithelial cell apoptosis. Animal experiments showed that exogenous PGE2 induced DE symptoms. Blocking EP2/4 not only inhibited the proportion of Th17, but also alleviated the apoptosis of corneal epithelial cells caused by PGE2. PGE2 induces aggravation of inflammation by promoting the level of Th17 in the ocular surface, and causes corneal epithelial cell apoptosis, thereby participating in the progression of DE.

Mechanism of non-small cell lung cancer cell-derived exosome miR-196b-5p promoting pyroptosis of tumor T cells and tumor cell proliferation by downregulating ING5

In the world, lung cancer is one of the most common malignant cancers and has become the leading cause of death of cancers in China, among which non-small cell lung cancer (NSCLC) accounts for a relatively high proportion, but there is a lack of effective treatment at present. An animal model of NSCLC was established, and BEAS-2b, H1299, Lewis, and T cells were used for subsequent experimental verification. The level of miR-196b-5p was detected by quantitative real-time polymerase chain reaction. Growth inhibitor 5 (ING5), CD9, CD63, HSP70, Caspase-1, NLRP3, and GSDMD-NT were detected by western blot. The level of ING5 was confirmed by immunohistochemistry, the location of miR-196b-5p was analyzed by fluorescence in situ hybridization (FISH), cell viability was investigated by Cell Counting Kit-8 kit, and interleukin (IL)-1β and IL-18 were confirmed by enzyme-linked immunosorbent assay. Cell apoptosis was detected by flow cytometry. In addition, the binding site was verified by dual-luciferase reporter gene experiments. Tumor volume was measured. TUNEL staining was used to detect apoptosis. Flow cytometry was used to measure the levels of CD8 T, CD4 T, and Treg cells in tumors. miR-196-5p was highly expressed in exosomes secreted by tumor cells. miR-196-5p negatively targeted ING5 to promote the growth of tumor cells. Cancer-derived exosomes promote pyroptosis of T cells to further aggravate the development of cancer. Exosome-derived miR-196b-5p promoted pyroptosis of T cells. Exosome-derived miR-196b-5p inhibited the level of ING5 to promote tumor growth and accelerate the process of NSCLC.

Dermatophagoides Pteronyssinus 1 (DerP1) May Trigger NLRP3-Mediated Corneal Epithelial Cell Pyroptosis by Elevating Interleukin-33 Expression Levels

PURPOSE

To characterize the in vivo effects of Dermatophagoides pteronyssinus 1 (DerP1) in mice and determine the underlying NLRP3 inflammasome-mediated pyroptosis signaling mechanisms in the human corneal epithelial cells (HCECs).

METHODS

DerP1 was used to induce allergic conjunctivitis in C57 mice. HCECs were sensitized with DerP1 in vitro to mimic their condition observed in allergic conjunctivitis in vivo. Transmission electron microscopy was used to evaluate pyroptosis in the HCECs, enzyme-linked immunosorbent assays to assess interleukin (IL)-33, IL-1β and IL-4 levels, flow cytometry to detect the proportion of Th2 cells, MTT assays to assess cell metabolic activity, immunofluorescence to evaluate the effects of DerP1 on functional HCEC phenotypes, and Western blot assays to detect the expression of NOD-like receptor family pyrin domain-containing 3 (NLRP3), gasdermin D (GSDMD), N-terminal fragment of GSDMD (GSDMD-N), pro-caspase-1, cleaved caspase-1, IL-1β, and IL-33. IL-33 expression in the HCECs was knocked down via lentivirus transfection.

RESULTS

In vivo, DerP1 promotes pyroptosis, production of Th2 inflammatory cytokines and IL-33, and NLRP3 activation in mouse corneas. In vitro, pyroptotic bodies were found in the HCECs after sensitization with DerP1. Various concentrations of DerP1 increased the expression levels of NLRP3, GSDMD, GSDMD-N, pro-caspase-1, cleaved caspase-1, and IL-1β in the HCECs, with the largest increase observed after exposure to 20 µM DerP1. In vitro, recombinant human IL-33 mediated the expression of pyroptotic biomarkers in the HCECs, whereas IL-33 silencing diminished 20 µM DerP1-induced increase in their expression levels.

CONCLUSIONS

DerP1 induces pyroptosis and allergic conjunctivitis, the expression of Th2 inflammatory cytokines, NLRP3 activation, and IL-33 in mouse corneas in our model. These effects would attribute to its activating NLRP3-GSDMD signaling pathway axis via enhancing IL-33 expression in HCECs.

Construction of an Exudative Age-Related Macular Degeneration Diagnostic and Therapeutic Molecular Network Using Multi-Layer Network Analysis, a Fuzzy Logic Model, and Deep Learning Techniques: Are Retinal and Brain Neurodegenerative Disorders Related?

Neovascular age-related macular degeneration (nAMD) is a leading cause of irreversible visual impairment in the elderly. The current management of nAMD is limited and involves regular intravitreal administration of anti-vascular endothelial growth factor (anti-VEGF). However, the effectiveness of these treatments is limited by overlapping and compensatory pathways leading to unresponsiveness to anti-VEGF treatments in a significant portion of nAMD patients. Therefore, a system view of pathways involved in pathophysiology of nAMD will have significant clinical value. The aim of this study was to identify proteins, miRNAs, long non-coding RNAs (lncRNAs), various metabolites, and single-nucleotide polymorphisms (SNPs) with a significant role in the pathogenesis of nAMD. To accomplish this goal, we conducted a multi-layer network analysis, which identified 30 key genes, six miRNAs, and four lncRNAs. We also found three key metabolites that are common with AMD, Alzheimer's disease (AD) and schizophrenia. Moreover, we identified nine key SNPs and their related genes that are common among AMD, AD, schizophrenia, multiple sclerosis (MS), and Parkinson's disease (PD). Thus, our findings suggest that there exists a connection between nAMD and the aforementioned neurodegenerative disorders. In addition, our study also demonstrates the effectiveness of using artificial intelligence, specifically the LSTM network, a fuzzy logic model, and genetic algorithms, to identify important metabolites in complex metabolic pathways to open new avenues for the design and/or repurposing of drugs for nAMD treatment.

DNMT1 regulates miR-20a/TXNIP-mediated pyroptosis of retinal pigment epithelial cells through DNA methylation

BACKGROUND

Pyroptosis of retinal pigment epithelium (RPE) cells is associated with the etiology of diabetic retinopathy (DR). In this study, we investigated the effect of DNMT1 on RPE cell pyroptosis by regulating miR-20a/TXNIP expression through DNA methylation.

METHODS

High glucose (HG)-induced ARPE-19 cells and mice were injected with streptozotocin (STZ) to generate DR cells and animal models. RT‒qPCR was used to detect the expression of miR-20a, and methylation-specific PCR (MS-PCR) was used to determine the occurrence of methylation of miR-20a. The expression of pyroptosis-related proteins (caspase-1 and NLRP3) and DNA methyltransferase (DNMT1) was detected by western blotting, and the expression of inflammatory factors (IL-1β and IL-18) was detected by ELISA. Apoptosis was detected by flow cytometry and TUNEL. HE staining was used to observe the pathological changes in retinal tissue in mice.

RESULTS

In HG-induced DR cell models, the expression of miR-20a was significantly downregulated, while the expression of inflammatory factors (IL-1β, IL-18) and pyroptosis-associated proteins (caspase-1, NLRP3) was significantly upregulated. Transfection of miR-20a mimic can effectively reverse HG-induced pyroptosis and release of inflammatory factors. DNMT1 promotes miR-20a methylation and inhibits the expression of miR-20a. DNMT1-mediated methylation is involved in the pyroptosis process of high glucose-induced RPE cells, and silencing DNMT1 can promote the expression of miR-20a, thereby inhibiting the release of IL-1β and IL-18 and reducing the occurrence of cell pyroptosis. miR-20a targets negative regulation of TXNIP expression, and overexpression of TXNIP can effectively reverse the inhibitory effect of miR-20a on pyroptosis. The methylation inhibitor 5-AZ can inhibit the occurrence of pyroptosis and DR processes, while treatment with a miR-20a inhibitor or OE-TXNIP can reverse the effect of 5-AZ.

CONCLUSION

DNMT1 promotes DNA methylation, decreases the expression of miR-20a and increases the expression of TXNIP, which ultimately leads to the occurrence of pyroptosis in RPE cells.

The role of NLRP12 in inflammatory diseases

Nucleotide-binding leucine-rich repeat-containing receptor 12 (NLRP12), a highly conserved protein containing an N-terminal pyrin domain (PYD), a nucleotide-binding domain and a C-terminal leucine-rich repeat region, belongs to the nucleotide-binding oligomerization domain-like receptor-containing PYD (NLRP) family and is a cytoplasmic sensor that plays a negative role in inflammation. NLRP12 is involved in multiple disease processes, including formation of inflammasomes and regulation of both canonical and noncanonical inflammatory signaling pathways. NLRP12 and pathogenic infections are closely linked, and alterations in NLRP12 expression and activity are associated with inflammatory diseases. In this review, we begin with a summary of the mechanisms of negative regulation by NLRP12. We then underscore the important roles of NLRP12 in the onset and progression of inflammation, infectious disease, host defense, carcinogenesis and COVID-19. Finally, we highlight factors that influence NLRP12 activity, including synthetic and naturally derived agonists, and are regarded as potential therapeutic agents to overcome inflammatory diseases.

Hyperosmolarity promotes macrophage pyroptosis by driving the glycolytic reprogramming of corneal epithelial cells in dry eye disease

Tear film hyperosmolarity plays a core role in the development of dry eye disease (DED) by mediating the disruption of ocular surface homeostasis and triggering inflammation in ocular surface epithelium. In this study, the mechanisms involving the hyperosmolar microenvironment, glycolysis mediating metabolic reprogramming, and pyroptosis were explored clinically, in vitro, and in vivo. Data from DED clinical samples indicated that the expression of glycolysis and pyroptosis-related genes, including PKM2 and GSDMD, was significantly upregulated and that the secretion of IL-1β significantly increased. In vitro, the indirect coculture of macrophages derived from THP-1 and human corneal epithelial cells (HCECs) was used to discuss the interaction among cells. The hyperosmolar environment was found to greatly induce HCECs' metabolic reprogramming, which may be the primary cause of the subsequent inflammation in macrophages upon the activation of the related gene and protein expression. 2-Deoxy-d-glucose (2-DG) could inhibit the glycolysis of HCECs and subsequently suppress the pyroptosis of macrophages. In vivo, 2-DG showed potential efficacy in relieving DED activity and could significantly reduce the overexpression of genes and proteins related to glycolysis and pyroptosis. In summary, our findings suggested that hyperosmolar-induced glycolytic reprogramming played an active role in promoting DED inflammation by mediating pyroptosis.

NLRP3 Inflammasome as a Potential Therapeutic Target in Dry Eye Disease

Dry eye disease (DED) is a multifactorial ocular surface disorder arising from numerous interrelated underlying pathologies that trigger a self-perpetuating cycle of instability, hyperosmolarity, and ocular surface damage. Associated ocular discomfort and visual disturbance contribute negatively to quality of life. Ocular surface inflammation has been increasingly recognised as playing a key role in the pathophysiology of chronic DED. Current readily available anti-inflammatory agents successfully relieve symptoms, but often without addressing the underlying pathophysiological mechanism. The NOD-like receptor protein-3 (NLRP3) inflammasome pathway has recently been implicated as a key driver of ocular surface inflammation, as reported in pre-clinical and clinical studies of DED. This review discusses the intimate relationship between DED and inflammation, highlights the involvement of the inflammasome in the development of DED, describes existing anti-inflammatory therapies and their limitations, and evaluates the potential of the inflammasome in the context of the existing anti-inflammatory therapeutic landscape as a therapeutic target for effective treatment of the disease.

The role of regulated necrosis in inflammation and ocular surface diseases

In recent decades, numerous types of regulated cell death have been identified, including pyroptosis, ferroptosis and necroptosis. Regulated necrosis is characterized by a series of amplified inflammatory responses that result in cell death. Therefore, it has been suggested to play an essential role in the pathogenesis of ocular surface diseases. The cell morphological features and molecular mechanisms of regulated necrosis are discussed in this review. Furthermore, it summarizes the role of ocular surface diseases, such as dry eye, keratitis, and cornea alkali burn, as potential disease prevention and treatment targets.

The role of pyroptosis in inflammatory diseases

Programmed cell death has crucial roles in the physiological maturation of an organism, the maintenance of metabolism, and disease progression. Pyroptosis, a form of programmed cell death which has recently received much attention, is closely related to inflammation and occurs via canonical, non-canonical, caspase-3-dependent, and unclassified pathways. The pore-forming gasdermin proteins mediate pyroptosis by promoting cell lysis, contributing to the outflow of large amounts of inflammatory cytokines and cellular contents. Although the inflammatory response is critical for the body's defense against pathogens, uncontrolled inflammation can cause tissue damage and is a vital factor in the occurrence and progression of various diseases. In this review, we briefly summarize the major signaling pathways of pyroptosis and discuss current research on the pathological function of pyroptosis in autoinflammatory diseases and sterile inflammatory diseases.

Effects of TCPP and TCEP exposure on human corneal epithelial cells: Oxidate damage, cell cycle arrest, and pyroptosis

Tris(2-chloroisopropyl) phosphate (TCPP) and Tris(2-chloroethyl) phosphate (TCEP) are the widely used organophosphorus flame retardants indoors and easily accessible to the eyes as the common adhesive components of dust and particle matter, however, hardly any evidence has demonstrated their corneal toxicity. In this study, the adverse effects of TCPP, TCEP, and TCPP + TCEP exposure on human corneal epithelial cells (HCECs) were investigated. The cell viability and morphology, intracellular reactive oxygen species (ROS), cell cycle, and the expressions of cell cycle and pyroptosis-related genes were assessed to explain the underlying mechanisms. Compared to individual exposure, co-exposure to TCPP₂₀+TCEP₂₀ showed higher cytotoxicity with a sharp decrease of >30% in viability and more serious oxidative damage by increasing ROS production to 110.92% compared to the control group. Furthermore, the cell cycle arrested at the S phase (36.20%) was observed after combined treatment, evidenced by the upregulation of cyclin D1, CDK2, CDK4, CDK6, p21, and p27. Interestingly, pyroptosis-related genes GSDMD, Caspase-1, NLRP3, IL-1β, IL-18, NLRP1, and NLRC4 expressions were promoted with cell swelling and glowing morphology. Oxidative stress and cell cycle arrest probably acted as a key role in TCPP₂₀+TCEP₂₀-induced cytotoxicity and pyroptosis in HCECs. Our results suggested that TCPP₂₀+TCEP₂₀ co-exposure induced severer corneal damage, further illustrating its significance in estimating indoor health hazards to humans.

BMSC reduces ROS and inflammation levels by inhibiting TLR4/MYD88/NF-κB signaling axis to alleviate dry eye

Objective To investigate the therapeutic effect of Bone marrow mesenchymal stem cells (BMSCs) on dry eye mice, and to investigate the mechanism of TLR4/MYD88/NF-κB signaling pathway on corneal injury repair in dry eye mice. Methods To establish a hypertonic dry eye cell model. Western blot for measureing the protein expressions of caspase-1, IL-1β，NLRP3 and ASC，and Rt-qpcr for mRNA expression. Flow cytometry for detecting the ROS content and apoptosis rate. CCK-8 for detecting the proliferation activity of cells, and ELISA for the levels of inflammation-related factors.The levels of inflammation-related factors were detected by ELISA. The dry eye mouse model of benzalkonium chloride was established. Three clinical parameters used to evaluate ocular surface damage, namely tear secretion, tear film rupture time and corneal sodium fluorescein staining, were measured with phenol cotton thread. Flow cytometry and TUNEL staining are both for he apoptosis rate. Western blot also for detecting the protein expressions of TLR4, MYD88, NF-κB, inflammation-related factors and apoptosis-related factors . The pathological changes were evaluated by HE and PAS staining. Results In vitro, BMSCs and inhibitors of TLR4, MYD88 and NF-κB showed decreased ROS content, decreased inflammatory factor protein level, decreased apoptotic protein level and increased mRNA expression compared with NaCl group. BMSCS partially reversed cell apoptosis induced by NaCl and improved cell proliferation. In vivo, it reduces corneal epithelial defects, goblet cell loss and inflammatory cytokine production, and increases tear production. In vitro, BMSC and inhibitors of TLR4, MYD88 and NF-κB could protect mice from apoptosis induced by hypertonic stress. In terms of mechanism, NACL-induced NLRP3 inflammasome formation, caspase-1 activation and IL-1β maturation can be inhibited. Conclusion BMSCs treatment can reduce ROS and inflammation levels and alleviate dry eye by inhibiting TLR4/MYD88/NF-κBsignaling pathway.

Rapamycin suppresses neuroinflammation and protects retinal ganglion cell loss after optic nerve crush

Pyroptosis, an inflammasome-mediated mode of death, plays an important role in glaucoma. It has been shown that regulating the mTOR pathway can inhibit pyroptosis. Unfortunately, whether rapamycin (RAPA), a specific inhibitor of the mTOR pathway, can inhibit optic nerve crush (ONC)-induced pyroptosis to protect retinal ganglion cells (RGCs) has not been investigated. Our research aimed to confirm the effect of intravitreal injection of RAPA on RGCs. Furthermore, we used the ONC model to explore the underlying mechanisms. First, we observed that intravitreal injection of RAPA alleviated RGC damage induced by various types of injury. We then used the ONC model to further explore the potential mechanism of RAPA. Mechanistically, RAPA not only reduced the activation of glial cells in the retina but also inhibited retinal pyroptosis-induced expression of inflammatory factors such as nucleotide-binding oligomeric domain-like receptor 3 (NLRP3), apoptosis-associated speckle-like protein containing a CARD (ASC), N-terminal of gasdermin-D (GSDMD-N), IL-18 and IL-1β. Moreover, RAPA exerted protective effects on RGC axons, possibly by inhibiting glial activation and regulating the mTOR/ROCK pathway. Therefore, this study demonstrates a novel mechanism by which RAPA protects against glaucoma and provides further evidence for its application in preclinical studies.

Cyclosporin A improves the hyperosmotic response in an experimental dry eye model by inhibiting the HMGB1/TLR4/NF-κB signaling pathway

Hyperosmolarity is closely related to dry eye disease (DED), which induces corneal epithelial cell structure and dysfunction leading to ocular surface inflammation. Cyclosporine A (CSA) is a cyclopeptide consisting of 11 deduced amino acids. It has an immunosuppressive effect and shows a vital function in inhibiting the inflammatory response. The mechanism of CSA in DED is still not entirely clear. This experiment aimed to investigate the possible mechanism of CSA in the hyperosmotic DED model. This study found that CSA can inhibit the transcript levels of DED high mobility group protein 1 (HMGB1), Toll-like receptor 4 (TLR4) and nuclear transcription factor κB (NF-κB) in signaling pathways. In addition, the study also found that 550 mOsm/L can induce the formation of DED models in vivo or in vitro. Furthermore, different concentrations of CSA have different effects on the expression of HMGB1 in human corneal epithelial cells under hyperosmotic stimulation, and high concentrations of CSA may increase the expression of HMGB1. In addition, CSA effectively reduced the corneal fluorescence staining score of the DE group and increased the tear volume of mice. Therefore, this experimental investigation might supply new evidence for the mechanism of CSA in DED, provide a potential new therapy for treating DED, and provide a theoretical basis for CSA treatment of DED.

IFN-γ Facilitates Corneal Epithelial Cell Pyroptosis Through the JAK2/STAT1 Pathway in Dry Eye

Purpose

To investigate the effect of gamma interferon (IFN-γ) on corneal epithelial pyroptosis in an experimental dry eye (DE) model and explore the underlying molecular mechanisms.

Methods

Experimental DE was established in adult wild-type (WT) C57BL/6 mice and Ifng-knockout mice on a C57BL/6 background by subcutaneous injection of scopolamine (1.5 mg/0.3 mL, three times per day) and exposure to desiccating stress. An immortalized human corneal epithelial cell line (HCE-T) was treated with IFN-γ under hyperosmolar conditions. Corneal epithelial defects, tear production, and conjunctival goblet cells were detected by fluorescein sodium staining, the phenol red cotton test, and periodic acid-Schiff staining. The mRNA expression was measured by quantitative real-time PCR. Changes in protein expression were analyzed by Western blotting and immunofluorescence staining. Cell Counting Kit-8 and lactate dehydrogenase assays and in situ TUNEL staining were used to assess cell death.

Results

The expression of IFNG and its related genes was increased in the corneas of DE mice, whereas genetic deletion of Ifng ameliorated desiccating stress-induced dry eye symptoms. We further found that IFN-γ activated the JAK2/STAT1 signaling pathway inducing corneal epithelial pyroptosis. Topical application of a STAT1 inhibitor in vivo or siRNA targeting STAT1 in vitro suppressed pyroptosis of corneal epithelial cells. In addition, the production of reactive oxygen species (ROS) was elevated in DE, and a reduction in excessive ROS release prevented pyroptosis.

Conclusions

The increase in IFN-γ participates in the pathogenesis of dry eye and promotes corneal epithelial pyroptosis by activating the JAK2/STAT1 signaling pathway. Oxidative stress might be in downstream of JAK2/STAT1, thereby contributing to pyroptosis.

A20 functions as a negative regulator of the lipopolysaccharide-induced inflammation in corneal epithelial cells

A20, also called TNFAIP3, is a crucial regulator of inflammation in various diseases but has not evidenced its function in the cornea. We aimed to evaluate the existence and the functions of A20 in human corneal epithelial (HCE-T) cells. After being treated with lipopolysaccharide (LPS) in different concentrations or at separate times, cells were collected to analyze A20 expressions. We then constructed the A20 knockdown system by siRNA and the A20 overexpressing system by lentivirus transduction. Systems were further exposed to medium with or without LPS for indicated times. Next, we evaluated the production of inflammatory cytokines (IL-6 and IL-8) by qRT-PCR and ELISA. Also, the translocation of P65 and the phosphorylation of P65, P38 and JNK were observed in two systems. In addition, we used the nuclear factor kappa-B (NF-κB) antagonist TPCA-1 for the pretreatment in cells and then detected the A20 expressions. We found a low basal expression of A20 in HCE-T cells, and the expressions could be dose-dependently induced by LPS, peaking at 4 h in protein level after stimulation. Both the A20 knockdown and A20 overexpressing systems were confirmed to be effective. After the LPS treatment, productions of IL-6 and IL-8 were enhanced in the A20 knockdown system and reduced in the A20 overexpressing system. A20 reduced the translocation of P65 into the nucleus and the phosphorylation of P65, P38 and JNK. Furthermore, TPCA-1 pretreatment reduced the expression of A20 in cells. We concluded that A20 is a potent regulator for corneal epithelium's reaction to inflammation, and it thus is expected to be a potential therapy target for ocular surface diseases.

Aim2 Deficiency Ameliorates Lacrimal Gland Destruction and Corneal Epithelium Defects in an Experimental Dry Eye Model

Purpose

Dry eye disease (DED) is a multifactorial disease that is associated with inflammation. Excessive DNA is present in the tear fluid of patients with DED. Absent in melanoma 2 (AIM2) is a key DNA sensor. This study aimed to investigate the role of AIM2 in the pathogenesis of DED.

Methods

DED was induced by injection of scopolamine (SCOP). Aberrant DNA was detected by cell-free DNA (cfDNA) ELISA and immunostaining. Corneal epithelial defects were assessed by corneal fluorescein staining, zonula occludens-1 immunostaining and TUNEL. Tear production was analyzed by phenol red thread test. Lacrimal gland (LG) histology was evaluated by hematoxylin and eosin staining, and transmission electron microscopy examination. Macrophage infiltration in LG was detected by immunohistochemistry for the macrophage marker F4/80. Gene expression was analyzed by RT-qPCR. Protein production was examined by immunoblot analysis or ELISA.

Results

Aim2-/- mice displayed a normal structure and function of LG and cornea under normal conditions. In SCOP-induced DED, wild type (WT) mice showed increased cfDNA in tear fluid, and aberrant accumulations of dsDNA accompanied by increased AIM2 expression in the LG. In SCOP-induced DED, WT mice displayed damaged structures of LG, reduced tear production, and severe corneal epithelium defects, whereas Aim2-/- mice had a better preserved LG structure, less decreased tear production, and improved clinical signs of dry eye. Furthermore, genetic deletion of Aim2 suppressed the increased infiltration of macrophages and inhibited N-GSDMD and IL18 production in the LG of SCOP-induced DED.

Conclusions

Aim2 deficiency alleviates ocular surface damage and LG inflammation in SCOP-induced DED.

The inflammasome pathway: A key player in ocular surface and anterior segment diseases

Inflammasomes are multicomplex molecular regulators with an emerging importance in regulating ocular surface and anterior segment health and disease. Key components found in the eye include NF-κB, NLRP3, NLRC4, NLRP6, ASC, IL-1β, IL-18, and caspase-1. The role of NLRP1, NLRC4, AIM2, and NLRP3 inflammasomes in the pathogenesis of infectious ulcers, DED, uveitis, glaucoma, corneal edema, and other diseases is being studied with many developments. Attenuation of these diseases has been explored by blocking various molecules along the inflammasome pathway with agents like NAC, polydatin, calcitriol, glyburide, YVAD, and disulfiram. We provide a background on the inflammasome pathway as it relates to the ocular surface and anterior segment of the eye, discuss the role of inflammasomes in the above diseases in animals and humans, investigate new therapeutic targets, and explore the efficacy of new anti-inflammasome therapies.

Dynasore Protects Corneal Epithelial Cells Subjected to Hyperosmolar Stress in an In Vitro Model of Dry Eye Epitheliopathy

Epitheliopathy at the ocular surface is a defining sign of dry eye disease, a common disorder that affects 10% to 30% of the world's population. Hyperosmolarity of the tear film is one of the main drivers of pathology, with subsequent endoplasmic reticulum (ER) stress, the resulting unfolded protein response (UPR), and caspase-3 activation implicated in the pathway to programmed cell death. Dynasore, is a small molecule inhibitor of dynamin GTPases that has shown therapeutic effects in a variety of disease models involving oxidative stress. Recently we showed that dynasore protects corneal epithelial cells exposed to the oxidant tBHP, by selective reduction in expression of CHOP, a marker of the UPR PERK branch. Here we investigated the capacity of dynasore to protect corneal epithelial cells subjected to hyperosmotic stress (HOS). Similar to dynasore's capacity to protect against tBHP exposure, dynasore inhibits the cell death pathway triggered by HOS, protecting against ER stress and maintaining a homeostatic level of UPR activity. However, unlike with tBHP exposure, UPR activation due to HOS is independent of PERK and mostly driven by the UPR IRE1 branch. Our results demonstrate the role of the UPR in HOS-driven damage, and the potential of dynasore as a treatment to prevent dry eye epitheliopathy.

The Potential Role of Regulated Cell Death in Dry Eye Diseases and Ocular Surface Dysfunction

The research on new treatments for dry eye diseases (DED) has exponentially grown over the past decades. The increased prevalence of dry eye conditions, particularly in the younger population, has received much attention. Therefore, it is of utmost importance to identify novel therapeutical targets. Regulated cell death (RCD) is an essential process to control the biological homeostasis of tissues and organisms. The identification of different mechanisms of RCD stimulated the research on their involvement in different human pathologies. Whereas apoptosis has been widely studied in DED and included in the DED vicious cycle, the role of RCD still needs to be completely elucidated. In this review, we will explore the potential roles of different types of RCD in DED and ocular surface dysfunction. Starting from the evidence of oxidative stress and inflammation in dry eye pathology, we will analyse the potential therapeutic applications of the following principal RCD mechanisms: ferroptosis, necroptosis, and pyroptosis.

Suppression of NLRP3/Caspase-1/GSDMD Mediated Corneal Epithelium Pyroptosis Using Melatonin-Loaded Liposomes to Inhibit Benzalkonium Chloride-Induced Dry Eye Disease

Introduction

Benzalkonium chloride (BAC) is widely employed as a preservative in eye drops, which will cause the death of corneal epithelial cells due to ROS production, DNA strand breakage, and mitochondrial dysfunction, resulting in dry eye disease (DED)-like changes in ocular surface tissues. In this study, Melatonin (MT) liposomes (TAT-MT-LIPs) designed by loading MT into TAT-modified liposomes have been developed, characterized, and used for inhibiting BAC-induced DED (BAC-DED).

Methods

The TAT was chemically grafted onto the Mal-PEG₂₀₀₀-DSPE by Michael's addition between the sulfhydryl group in TAT and the maleimide group in Mal-PEG₂₀₀₀-DSPE. TAT-MT-LIPs were prepared using film dispersion followed by the extrusion method and topically treated in rats once a day. BAC-DED was induced in rats by topical administration with 0.2% BAC twice daily. Defects, edema, and inflammation of the corneas, as well as IOP, were examined. Histologic analyses of corneas were performed to assess the change of mitochondrial DNA oxidation and NLRP3/Caspase-1/GSDMD signaling transduction.

Results

After topical administration, TAT-MT-LIPs significantly alleviated DED-clinical symptoms of experimental animals by inhibiting tissue inflammation and preventing the loss of the corneal epithelium and conjunctival goblet cells. Our data suggested continuous ocular surface exposure of BAC-induced NLRP3/Caspase-1/GSDMD mediated corneal epithelium pyroptosis, which was not reported before. BAC caused substantial mt-DNA oxidation, which promoted the transduction of NLRP3/Caspase-1/GSDMD and consequent corneal epithelium pyroptosis. TAT-MT-LIPs could efficiently suppress the BAC-induced corneal epithelium pyroptosis and inflammation by inhibiting mt-DNA oxidation and the subsequent signal transmission.

Conclusion

NLRP3/Caspase-1/GSDMD mediated corneal epithelium pyroptosis is involved in the development of BAC-DED. The present study provided new insights into the adverse effects of BAC, which can serve as a new target for protecting corneal epithelium when applying BAC as a preservative in eye drops. The developed TAT-MT-LIPs can efficiently inhibit BAC-DED and give great potential to be developed as a new DED treatment.

Cathepsins Trigger Cell Death and Regulate Radioresistance in Glioblastoma

Treatment of glioblastoma (GBM) remains very challenging, and it is particularly important to find sensitive and specific molecular targets. In this work, we reveal the relationship between the expression of cathepsins and radioresistance in GBM. We analyzed cathepsins (cathepsin B, cathepsin D, cathepsin L, and cathepsin Z/X), which are highly associated with the radioresistance of GBM by regulating different types of cell death. Cathepsins could be potential targets for GBM treatment.

Mechanism of LSD1 in oxygen-glucose deprivation/reoxygenation-induced pyroptosis of retinal ganglion cells via the miR-21-5p/NLRP12 axis

Background

Retinal ganglion cells (RGCs) are important retinal neurons that connect visual receptors to the brain, and lysine-specific demethylase 1 (LSD1) is implicated in the development of RGCs. This study expounded the mechanism of LSD1 in oxygen-glucose deprivation/reoxygenation (OGD/R)-induced pyroptosis of RGCs.

Methods

Mouse RGCs underwent OGD/R exposure, and then RGC viability was examined using the cell counting kit-8 method. The mRNA levels of Caspase 1, the protein levels of NOD-like receptor family pyrin domain-containing 3 (NLRP3), N-terminal fragment of gasdermin D (GSDMD-N), and cleaved-Caspase1, and the concentrations of interleukin (IL)-1β and IL-18 were respectively examined. Subsequently, LSD1 expression was intervened to explore the underlying effect of LSD1 on OGD/R-induced pyroptosis of RGCs. Afterwards, the enrichments of LSD1 and histone H3 lysine 4 methylation (H3K4me) 1/2 on the microRNA (miR)-21-5p promoter were determined using chromatin-immunoprecipitation assay. And the binding interaction between miR-21-5p and NLRP12 was detected using dual-luciferase and RNA pull-down assays. Finally, the effects of miR-21-5p/NLRP12 on LSD1-mediated pyroptosis of RGCs were verified through functional rescue experiments.

Results

OGD/R treatment increased pyroptosis of RGCs and LSD1 expression. Silencing LSD1 declined levels of Caspase 1 mRNA, NLRP3, GSDMD-N, cleaved-Caspase1, IL-1β, and IL-18 and limited pyroptosis of OGD/R-treated RGCs. Mechanically, LSD1 suppressed miR-21-5p expression via demethylation of H3K4me2 on the miR-21-5p promoter to hamper the binding of miR-21-5p to NLRP12, and thereby increased NLRP12 expression. Silencing miR-21-5p or overexpressing NLRP12 facilitated OGD/R-induced pyroptosis of RGCs.

Conclusion

LSD1-mediated demethylation of H3K4me2 decreased miR-21-5p expression to increase NLRP12 expression, promoting pyroptosis of OGD/R-treated RGCs.

Acacetin protects against depression-associated dry eye disease by regulating ubiquitination of NLRP3 through gp78 signal

Dry eye disease (DED) is a multifactorial syndrome that commonly occurs with depression. However, therapies targeting depression-related dry eye disease are rare. In the current study, we studied the beneficial effect of a natural flavone, acacetin, in depression-associated dry eye disease by utilizing the chronic unpredictable mild stress (CUMS) depression model. Our data showed that acacetin improved the depressive behaviors in sucrose preference test (SPT), tail suspension test (TST) and forced swim test (FST); relieved the dry eye symptoms including corneal epithelial impairments, tear production decrease and goblet cell loss in CUMS mice. Acacetin also inhibited NOD-like receptor protein 3 (NLRP3) inflammasome expression levels and suppressed inflammatory responses via enhancing glycoprotein 78 (gp78)/Insulin induced gene-1 (Insig-1)-controlled NLRP3 ubiquitination in CUMS mice. Furthermore, knockdown of gp78 compromised acacetin-conferred protective efficacy in depression-related dry eye disease. In summary, our findings indicated that acacetin exerts beneficial effect in depression-associated dry eye disease, which is tightly related to gp78-mediated NLRP3 ubiquitination.

AKR1C1 Protects Corneal Epithelial Cells Against Oxidative Stress-Mediated Ferroptosis in Dry Eye

Purpose

To evaluate the precise mode of cell death and to investigate the molecular mechanism underlying the initiation of inflammation in dry eye disease (DED).

Methods

C57BL/6 mice were injected with scopolamine subcutaneously and exposed to desiccating stress to establish a DED mouse model. An immortalized human corneal epithelial cell line (HCEC) was cultured under hyperosmolarity (500 mOsM). Protein expressions were measured using western blot assay and immunofluorescence staining. mRNA expression was analyzed by RNA-sequencing and quantitative RT-PCR. Transmission electron microscopy was used to observe the intracellular ultrastructure. Intracellular Fe²⁺ was detected by a FerroOrange fluorescent probe. Flow cytometry was used to evaluate the cellular reactive oxygen species and lipid peroxidation.

Results

Marked changes in ferroptosis-related markers expression, intracellular iron accumulation, and lipid peroxidation were observed in corneal epithelial cells of DED models. When excessive oxidative stress was suppressed, ferroptosis induced by hyperosmolarity in HCECs was restrained, as indicated by decreased iron content and lipid peroxidation levels. Moreover, AKR1C1 was upregulated by the activation of NRF2 in HCECs under hyperosmolarity. When AKR1C1 was knocked down, cell viability was decreased, accompanied by increased lipid peroxidation, whereas overexpression of AKR1C1 produced the opposite results. It was observed consistently that corneal defects and the inflammatory response were promoted after inhibition of AKR1C1 in vivo.

Conclusions

Excessive oxidative stress-induced ferroptosis participates in DED pathogenesis. The expression of AKR1C1 is triggered by NRF2 to decrease ferroptosis-induced cell damage and inflammation in HCECs. These findings may provide potential makers targeting ferroptosis and AKR1C1 for DED therapy.

Spotlight on pyroptosis: role in pathogenesis and therapeutic potential of ocular diseases

Pyroptosis is a programmed cell death characterized by swift plasma membrane disruption and subsequent release of cellular contents and pro-inflammatory mediators (cytokines), including IL‐1β and IL‐18. It differs from other types of programmed cell death such as apoptosis, autophagy, necroptosis, ferroptosis, and NETosis in terms of its morphology and mechanism. As a recently discovered form of cell death, pyroptosis has been demonstrated to be involved in the progression of multiple diseases. Recent studies have also suggested that pyroptosis is linked to various ocular diseases. In this review, we systematically summarized and discussed recent scientific discoveries of the involvement of pyroptosis in common ocular diseases, including diabetic retinopathy, age-related macular degeneration, AIDS-related human cytomegalovirus retinitis, glaucoma, dry eye disease, keratitis, uveitis, and cataract. We also organized new and emerging evidence suggesting that pyroptosis signaling pathways may be potential therapeutic targets in ocular diseases, hoping to provide a summary of overall intervention strategies and relevant multi-dimensional evaluations for various ocular diseases, as well as offer valuable ideas for further research and development from the perspective of pyroptosis.

IL-33 biology in cancer: An update and future perspectives

Interleukin-33 (IL-33) is a member of the IL-1 family of cytokines that is constitutively expressed in the nucleus of epithelial, endothelial and fibroblast-like cells. Upon cell stress, damage or necrosis, IL-33 is released into the cytoplasm to exert its prime role as an alarmin by binding to its specific receptor moiety, ST2. IL-33 exhibits pleiotropic function in inflammatory diseases and particularly in cancer. IL-33 may play a dual role as both a pro-tumorigenic and anti-tumorigenic cytokine, dependent on tumor and cellular context, expression levels, bioactivity and the nature of the inflammatory environment. In this review, we discuss the differential contribution of IL-33 to malignant or inflammatory conditions, its multifaceted effects on the tumor microenvironment, while providing possible explanations for the discrepant findings described in the literature. Additionally, we examine the emerging and divergent functions of IL-33 in the nucleus, and aspects of IL-33 biology that are currently under-addressed.

Role of Caspase-1 as a Biomarker of Ocular Surface Damage

PURPOSE

To examine the potential of caspase-1 as a biomarker for ocular surface damage.

DESIGN

Cross-sectional study.

METHODS

A total of 113 tear samples (64 subjects) were analyzed. Sixty-one samples were from individuals with dry eye disease (DED), defined as Ocular Surface Disease Index (OSDI) ≥13 and/or corneal staining (CS) ≥3; 32 were from individuals who used glaucoma medication, irrespective of DED metrics; and 20 were from controls (CS <3 and OSDI <13). All individuals completed a medical history form and underwent an ocular surface assessment. Protein levels of caspase-1 were determined by enzyme-linked immunosorbent assay off Schirmer's strips. The primary analysis compared caspase-1 levels in individuals with signs of ocular surface damage (CS ≥3) in both case groups and controls. Secondary correlational analyses were conducted to examine relationships between caspase-1 levels and ocular signs and symptoms. Finally, area under the curve (AUC) analyses were performed to examine relationships between inflammatory markers and CS.

RESULTS

The mean age of the population was 58±18 years; 70% were female. Tear samples from individuals with ocular surface damage presented higher caspase-1 levels than the control group. Caspase-1 levels showed a moderate positive correlation with CS (Spearman r = 0.31; P = .001) and eye redness (Spearman r = 0.39; P = .004), and a negative correlation with Schirmer's (Spearman r = -0.46; P < .001) and tear break-up time (Spearman r = -0.33; P = .0006). Caspase-1 showed higher sensitivity and AUC for detecting ocular surface damage than InflammaDry, and its expression was not affected by anti-inflammatory agents.

CONCLUSION

Caspase-1 levels were higher in the tears of individuals with ocular surface damage, suggesting its potential to be used as a biomarker and/or therapeutic target.

Long Noncoding RNA MIAT Regulates Hyperosmotic Stress-Induced Corneal Epithelial Cell Injury via Inhibiting the Caspase-1-Dependent Pyroptosis and Apoptosis in Dry Eye Disease

Purpose

The biological role and mechanism of long noncoding RNA (lncRNA) myocardial infarction-associated transcript (MIAT) in dry eye remain to be illustrated. Pyroptosis is a noticeable form of inflammatory activation, which is characteristic of gasdermin D (GSDMD)-driven cell death. The present study was designed to explore the role of MIAT in pyroptosis and apoptosis induced by hyperosmolarity stress (HS) in human corneal epithelial cells (HCECs).

Methods

HCECs were cultured in 70–120 mM hyperosmotic medium for 24 h to create a dry eye model in vitro. The level of the pyroptosis marker GSDMD was measured, and the cell inflammatory response was evaluated by detecting IL-1β and IL-18 levels. Exogenous caspase-1 inhibitor Ac-YVAD-CHO was used. The pyroptosis in HCECs was examined by caspase-1 activity, immunofluorescent staining, and Western blotting. Flow cytometry was performed to test the apoptosis rate of HCECs. Cell migration and proliferation were detected. The expression of the lncRNA MIAT in HCECs was detected by quantitative real-time PCR. MIAT was knocked down by small interfering RNA (siRNA) transfection. The effects of caspase-1 inhibition on pyroptosis, apoptosis, migration, and proliferation were observed.

Results

HS promoted pyroptosis in HCECs by elevating caspase-1, GSDMD, and the active cleavage of GSDMD (N-terminal domain, N-GSDMD), and increased the release of IL-1β, IL-18, LDH and the rate of apoptosis, with reduced cell migration. These changes were prevented by the inhibition of caspase-1. The expression of MIAT was significantly increased in HCECs exposed to a hyperosmotic medium. Silencing MIAT increased the expression of GSDMD, caspase-1, and inflammatory chemokines IL-1β and IL-18, and promoted apoptosis while inhibiting migration and proliferation in HCECs.

Conclusion

The lncRNA MIAT is involved in HS-induced pyroptosis and apoptosis and the inflammatory response of HCECs and provides a new understanding of the pathogenesis of dry eye.

Roles and Mechanisms of Regulated Necrosis in Corneal Diseases: Progress and Perspectives

Regulated necrosis is defined as cell death characterized by loss of the cell membrane integrity and release of the cytoplasmic content. It contributes to the development and progression of some diseases, including ischemic stroke injury, liver diseases, hypertension, and cancer. Various forms of regulated necrosis, particularly pyroptosis, necroptosis, and ferroptosis, have been implicated in the pathogenesis of corneal disease. Regulated necrosis of corneal cells enhances inflammatory reactions in the adjacent corneal tissues, leading to recurrence and aggravation of corneal disease. In this review, we summarize the molecular mechanisms of pyroptosis, necroptosis, and ferroptosis in corneal diseases and discuss the roles of regulated necrosis in inflammation regulation, tissue repair, and corneal disease outcomes.

Tacrolimus Loaded Cationic Liposomes for Dry Eye Treatment

Eye drops are ophthalmic formulations routinely used to treat dry eye. However, the low ocular bioavailability is an obvious drawback of eye drops owing to short ocular retention time and weak permeability of the cornea. Herein, to improve the ocular bioavailability of eye drops, a cationic liposome eye drop was constructed and used to treat dry eye. Tacrolimus liposomes exhibit a diameter of around 300 nm and a surface charge of +30 mV. Cationic liposomes could interact with the anionic ocular surface, extending the ocular retention time and improving tacrolimus amount into the cornea. The cationic liposomes notably prolonged the ocular retention time of eye drops, leading to an increased tacrolimus concentration in the ocular surface. The tacrolimus liposomes were also demonstrated to reduce reactive oxygen species and dry eye-related inflammation factors. The use of drug-loaded cationic liposomes is a good formulation in the treatment of ocular disease; the improved ocular retention time and biocompatibility give tremendous scope for application in the treatment of ocular disease, with further work in the area recommended.

TLR4-Dependent DUOX2 Activation Triggered Oxidative Stress and Promoted HMGB1 Release in Dry Eye

Dry eye disease (DED) is one of the most common ocular surface diseases worldwide. DED has been characterized by excessive accumulation of reactive oxygen species (ROS), following significant corneal epithelial cell death and ocular surface inflammation. However, the key regulatory factor remains unclear. In this study, we tended to explore whether DUOX2 contributed to DED development and the underlying mechanism. Human corneal epithelial (HCE) cells were treated with hyperosmolarity, C57BL/6 mice were injected of subcutaneous scopolamine to imitate DED. Expression of mRNA was investigated by RNA sequencing (RNA-seq) and quantitative real-time PCR (qPCR). Protein changes and distribution of DUOX2, high mobility group box 1 (HMGB1), Toll-like receptor 4 (TLR4), and 4-hydroxynonenal (4-HNE) were evaluated by western blot assays and immunofluorescence. Cell death was assessed by Cell Counting Kit-8 (CCK8), lactate dehydrogenase (LDH) release, and propidium iodide (PI) staining. Cellular ROS levels and mitochondrial membrane potential (MMP) were analyzed by flow cytometry. RNA-seq and western blot assay indicated a significant increase of DUOX2 dependent of TLR4 activation in DED both in vitro and in vivo. Immunofluorescence revealed significant translocation of HMGB1 within corneal epithelial cells under hyperosmolar stress. Interestingly, after ablated DUOX2 expression by siRNA, we found a remarkable decrease of ROS level and recovered MMP in HCE cells. Moreover, knockdown of DUOX2 greatly inhibited HMGB1 release, protected cell viability and abolished inflammatory activation. Taken together, our data here suggest that upregulation of DUOX2 plays a crucial role in ROS production, thereafter, induce HMGB1 release and cell death, which triggers ocular surface inflammation in DED.

In situ metabolic profile and spatial distribution of ocular tissues: New insights into dry eye disease

PURPOSE

Dry eye disease (DED) is a chronic multifactorial disorder affecting millions of people, yet the pathogenesis mechanisms still remain unclear. Matrix-assisted laser desorption ionization mass spectrometry imaging (MALDI-MSI) is a novel in situ visualization approach combined high-throughput mass spectrometry and molecular imaging. We aimed to explore the in situ ocular metabolic changes via MALDI-MSI to accelerate the recognition of DED pathogenesis.

METHODS

Experimental dry eye was established in Wistar rats by subcutaneous injection of scopolamine. The induction of DED was assessed by tear film breakup time, sodium fluorescein, histopathological staining and cell apoptosis. MALDI-MSI was applied to explore in situ ocular metabolomic in DED rats, and histopathological staining from same sections were used for side-by-side comparison with MALDI to annotate different tissue structures in the eye.

RESULTS

Considering the complexity of ocular tissue, we visualized the metabolites in specific ocular regions (central cornea, peripheral cornea, fornix conjunctiva, eyelid conjunctiva and aqueous humor), and identified metabolites related to DED, with information of relative abundance and spatial signatures. In addition, integrative pathway analysis illustrated that, several metabolic pathways such as glycerophospholipid, sphingolipid phenylalanine, and metabolism of glycine, serine and threonine were significantly altered in certain regions in the dry eye tissue. Moreover, we discussed how the metabolic pathways with spatiotemporal signatures might be involved in the DED process.

CONCLUSIONS

Our data exploit the advantages of in situ analysis of MALDI-MSI to accurately analyze the region-specific metabolic behaviors in DED, and provide new clues to uncover DED pathogenesis.

Pyroptosis: A New Insight Into Eye Disease Therapy

Pyroptosis is a lytic form of programmed cell death mediated by gasdermins (GSDMs) with pore-forming activity in response to certain exogenous and endogenous stimuli. The inflammasomes are intracellular multiprotein complexes consisting of pattern recognition receptors, an adaptor protein ASC (apoptosis speck-like protein), and caspase-1 and cause autocatalytic activation of caspase-1, which cleaves gasdermin D (GSDMD), inducing pyroptosis accompanied by cytokine release. In recent years, the pathogenic roles of inflammasomes and pyroptosis in multiple eye diseases, including keratitis, dry eyes, cataracts, glaucoma, uveitis, age-related macular degeneration, and diabetic retinopathy, have been continuously confirmed. Inhibiting inflammasome activation and abnormal pyroptosis in eyes generally attenuates inflammation and benefits prognosis. Therefore, insight into the pathogenesis underlying pyroptosis and inflammasome development in various types of eye diseases may provide new therapeutic strategies for ocular disorders. Inhibitors of pyroptosis, such as NLRP3, caspase-1, and GSDMD inhibitors, have been proven to be effective in many eye diseases. The purpose of this article is to illuminate the mechanism underlying inflammasome activation and pyroptosis and emphasize its crucial role in various ocular disorders. In addition, we review the application of pyroptosis modulators in eye diseases.

Autoimmunity in dry eye disease - An updated review of evidence on effector and memory Th17 cells in disease pathogenicity

The classic Th1/Th2 dogma has been significantly reshaped since the subsequent introduction of several new T helper cell subsets, among which the most intensively investigated during the last decade is the Th17 lineage that demonstrates critical pathogenic roles in autoimmunity and chronic inflammation - including the highly prevalent dry eye disease. In this review, we summarize current concepts of Th17-mediated disruption of ocular surface immune homeostasis that leads to autoimmune inflammatory dry eye disease, by discussing the induction, activation, differentiation, migration, and function of effector Th17 cells in disease development, highlighting the phenotypic and functional plasticity of Th17 lineage throughout the disease initiation, perpetuation and sustention. Furthermore, we emphasize the most recent advance in Th17 memory formation and function in the chronic course of dry eye disease, a major area to be better understood for facilitating the development of effective treatments in a broader field of autoimmune diseases that usually present a chronic course with recurrent episodes of flare in the target tissues or organs.

IL-36α/IL-36RA/IL-38 signaling mediates inflammation and barrier disruption in human corneal epithelial cells under hyperosmotic stress

PURPOSE

To explore the distinct expression and diverse roles of IL-36 cytokines in dry eye disease using an in vitro hyperosmolarity model of human corneal epithelial cells (HCECs).

METHODS

Primary HCECs were cultured from fresh donor limbal explants. Hyperosmolarity model was established by switching HCECs from isosmotic (312 mOsM) to hyperosmotic medium (350-500 mOsM) alone or with addition of rhIL-36RA or rhIL-38 for 2-48 h. Some cultures were treated with IL-36α (1-10 ng/ml) with or without rhIL-36RA or rhIL-38. Gene expression was detected by RT-qPCR; and protein production and barrier disruption were evaluated by ELISA and/or immunofluorescent staining.

RESULTS

IL-36 cytokines were differential expressed in primary HCECs. Among 3 pro-inflammatory agonists, IL-36α, but not IL-36β and IL-36γ, was distinctly induced at osmolarity-dependent manner while two antagonist IL-36RA and IL-38 were significantly suppressed in HCECs exposed to hyperosmotic stress. IL-36α increased to 4.4-fold in mRNA and 6.9-fold at protein levels (116.0 ± 36.33 pg/ml vs 16.79 ± 6.51 pg/ml in controls) by 450 mOsM, but dramatically inhibited by addition of rhIL-36RA or rhIL-38. Exogenous rhIL-36α stimulated expression of TNF-α and IL-1β at mRNA and protein levels and disrupted tight junction proteins ZO-1 and occludin. However, rhIL-36RA or rhIL-38 suppressed TNF-α and IL-1β production and protected HCECs from barrier disruption in response to IL-36α or hyperosmolarity.

CONCLUSIONS

Our findings demonstrate that the stimulated pro-inflammatory IL-36α with the suppressed antagonists IL-36RA and IL-38 is a novel mechanism by which hyperosmolarity induces inflammation in dry eye. IL-36RA and IL-38 may have a therapeutic potential in dry eye.

Calcitriol Alleviates Hyperosmotic Stress-Induced Corneal Epithelial Cell Damage via Inhibiting the NLRP3-ASC-Caspase-1-GSDMD Pyroptosis Pathway in Dry Eye Disease

Purpose

Inflammasome activation in response to elevated tear osmolarity behaves as an initial signal in dry eye-related corneal inflammation. Pyroptosis is another prominent consequence of inflammasome activation, which is featured by gasdermin D (GSDMD)-driven cell lysis. This study aims to explore the role of pyroptosis in dry eye, and also to verify if calcitriol, a potential therapeutic agent for dry eye, has certain effects against hyperosmotic stress (HS)-induced pyroptosis in human corneal epithelial cells (iHCECs) and the underlying mechanism.

Methods

The expression of pyroptosis executor GSDMD in tears from dry eye patients was examined using western blotting. iHCECs were grown in hyperosmotic medium (450 mOsM) to mimic the feature of elevated tear osmolality of dry eye in vitro. Exogenous calcitriol or pyroptosis inhibitor disulfiram was used. The extent of pyroptosis of iHCECs under various treatments was examined by scanning electron microscopy, caspase-1 and propidium iodide (PI) double staining by flow cytometry, immunofluorescent staining for ASC speck formation, and western blotting. Cell viability was measured by a CCK-8 assay and an LDH release assay.

Results

We found that pyroptosis was presented in dry eye patients, shown as the elevation of its effector GSDMD N-terminal domain (N-GSDMD) in patients' tears. Further in vitro results showed that HS promoted pyroptosis in human corneal epithelial cells, while exogeneous supplementation of disulfiram could reduce the number of iHCECs with pyroptotic markers. More importantly, we demonstrated that, in line with the effect of disulfiram, calcitriol could also alleviate HS-induced pyroptosis, through inhibiting the NLRP3-ASC-caspase-1-GSDMD pyroptosis pathway.

Conclusion

The current study provided direct evidence showing increased pyroptosis in dry eye patients. We demonstrated that calcitriol was able to effectively alleviate HS-induced corneal epithelial cell damage through inhibiting the NLRP3-ASC-caspase-1-GSDMD pyroptosis pathway. This study underlined calcitriol as a promising therapeutic agent for dry eye given its multiple therapeutic targets.

Melatonin ameliorates oxidative stress-mediated injuries through induction of HO-1 and restores autophagic flux in dry eye

This study aimed to investigate the protective effect of melatonin on the corneal epithelium in dry eye disease(DED) and explore its underlying mechanism. Human corneal epithelial(HCE) cells was exposure to t-butylhydroperoxide(tBH), C57BL/6 mice were injected of subcutaneous scopolamine to imitate DED. Melatonin was used both in vivo and in vitro. Cell viability was detected by Cell Counting Kit-8 assay and Lactate Dehydrogenase Leakage. The change of cellular reactive oxygen species (ROS) levels, mitochondrial membrane potential (MMP), and apoptosis was analyzed by flow cytometry. Western blot assays and immunofluorescence were carried out to measure protein changes. mRNA expression was investigated by RNA sequencing (RNA-Seq) and quantitative real-time PCR. The change of autophagic flux were observed through mCherry-GFP-LC3 transfection and electron microscopy(TEM). Clinical parameters of corneal epithelium defects, conjunctival goblet cells, tear volume, and level of ocular surface inflammation was recorded. Melatonin was able to reduce excessive ROS production and maintain mitochondrial function. TEM assay found melatonin rescued impaired autophagic flux under tBH. Moreover, melatonin significantly preserved cell viability, abolished LDH release, and decreased apoptosis. RNA-Seq indicated that melatonin greatly activating hemeoxygenase-1 (HO-1) expression. Interestingly, HO-1 ablation largely attenuated its protective effects. Besides, in dry eye mouse model, intraperitoneal injection of melatonin showed greatly improved clinical parameters, inhibited activated NLRP3 inflammation cascade, and increased density of goblet cells and tear volume. Thus, melatonin protects corneal epithelial cells from oxidative damage, maintain normal level of autophagy, and reduce inflammation via trigging HO-1 expression in DED.