Lipoxin A₄ inhibits platelet-activating factor inflammatory response and stimulates corneal wound healing of injuries that compromise the stroma

Lipoxin A4 (LXA4) Reduces Alkali-Induced Corneal Inflammation and Neovascularization and Upregulates a Repair Transcriptome

PURPOSE

To investigate the anti-inflammatory and anti-angiogenic effects of the bioactive lipid mediator LXA4 on a rat model of severe corneal alkali injury.

METHODS

To induce a corneal alkali injury in the right eyes of anesthetized Sprague Dawley rats. They were injured with a Φ 4 mm filter paper disc soaked in 1 N NaOH placed on the center of the cornea. After injury, the rats were treated topically with LXA4 (65 ng/20 μL) or vehicle three times a day for 14 days. Corneal opacity, neovascularization (NV), and hyphema were recorded and evaluated in a blind manner. Pro-inflammatory cytokine expression and genes involved in cornel repair were assayed by RNA sequencing and capillary Western blot. Cornea cell infiltration and monocytes isolated from the blood were analyzed by immunofluorescence and by flow cytometry.

RESULTS

Topical treatment with LXA4 for two weeks significantly reduced corneal opacity, NV, and hyphema compared to the vehicle treatment. RNA-seq and Western blot results showed that LXA4 decreased the gene and protein expression of pro-inflammatory cytokines interleukin (IL)-1β and IL-6 and pro-angiogenic mediators matrix metalloproteinase (MMP)-9 and vascular endothelial growth factor (VEGFA). It also induces genes involved in keratinization and ErbB signaling and downregulates immune pathways to stimulate wound healing. Flow cytometry and immunohistochemistry showed significantly less infiltration of neutrophils in the corneas treated with LXA4 compared to vehicle treatment. It also revealed that LXA4 treatment increases the proportion of type 2 macrophages (M2) compared to M1 in blood-isolated monocytes.

CONCLUSIONS

LXA4 decreases corneal inflammation and NV induced by a strong alkali burn. Its mechanism of action includes inhibition of inflammatory leukocyte infiltration, reduction in cytokine release, suppression of angiogenic factors, and promotion of corneal repair gene expression and macrophage polarization in blood from alkali burn corneas. LXA4 has potential as a therapeutic candidate for severe corneal chemical injuries.

LXA4 inhibits TGF-β1-induced airway smooth muscle cells proliferation and migration by suppressing the Smad/YAP pathway

The aims of the present study were to examine the signaling mechanisms for transforming growth factor-β1 (TGF-β1)-induced rat airway smooth muscle cells (ASMCs) proliferation and migration and to determine the effect of lipoxin A4 (LXA4) on TGF-β1-induced rat ASMCs proliferation and migration and its underlying mechanisms. TGF-β1 upregulated transcriptional coactivator Yes-associated protein (YAP) expression by activating Smad2/3 and then upregulated cyclin D1, leading to rat ASMCs proliferation and migration. This effect was reversed after treatment with the TGF-β1 receptor inhibitor SB431542. YAP is a critical mediator of TGF-β1-induced ASMCs proliferation and migration. Knockdown of YAP disrupted the pro-airway remodeling function of TGF-β1. Preincubation of rat ASMCs with LXA4 blocked TGF-β1-induced activation of Smad2/3 and changed its downstream targets, YAP and cyclin D1, resulting in the inhibition of rat ASMCs proliferation and migration. Our study suggests that LXA4 suppresses Smad/YAP signaling to inhibit rat ASMCs proliferation and migration and therefore has potential value in the prevention and treatment of asthma by negatively modulating airway remodeling.

Lipoxin Mimetics and the Resolution of Inflammation

Inflammation and its timely resolution are critical to ensure effective host defense and appropriate tissue repair after injury and or infection. Chronic, unresolved inflammation typifies many prevalent pathologies. The key mediators that initiate and drive the inflammatory response are well defined and targeted by conventional anti-inflammatory therapeutics. More recently, there is a growing appreciation that specific mediators, including arachidonate-derived lipoxins, are generated in self-limiting inflammatory responses to promote the resolution of inflammation and endogenous repair mechanisms without compromising host defense. We discuss the proresolving biological actions of lipoxins and recent efforts to harness their therapeutic potential through the development of novel, potent lipoxin mimetics generated via efficient, modular stereoselective synthetic pathways. We consider the evidence that lipoxin mimetics may have applications in limiting inflammation and reversing fibrosis and the underlying mechanisms.

Lipoxin A4 alleviates inflammation in Aspergillus fumigatus-stimulated human corneal epithelial cells by Nrf2/HO-1 signaling pathway

Purpose

To investigate the therapeutic effect of lipoxin A4 (LXA4) on Aspergillus fumigatus (A. fumigatus)-stimulated human corneal epithelial cells (HCECs).

Methods

The cell counting kit-8 (CCK-8) was performed in HCECs to evaluate the toxicity of LXA4. A cell scratch test was used to assess the impact of LXA4 on the migration of HCECs. Enzyme-linked immunosorbent assay (ELISA), quantitative real-time polymerase chain reaction (qRT-PCR), and western blot were applied to examine the expression of inflammatory mediators in A. fumigatus-stimulated HCECs. The nuclear factor erythroid 2-related factor 2 (Nrf2) nuclear translocation and expression in HCECs were detected by immunofluorescence staining.

Results

LXA4 at 0-10 nmol·L^-1 (nM) had no significant cytotoxic effect on HCECs. LXA4 at a concentration of 1 nM and 10 nM significantly promoted the migration rate of HCECs. The mRNA and protein levels of pro-inflammatory mediators, including IL-1β, TNF-α, and IL-6, were remarkably lower in the LXA4-treated group. LXA4 promoted the expression of Nrf2 and heme oxygenase 1 (HO-1) in A. fumigatus-stimulated HCECs compared with the PBS control group. Pretreatment with brusatol (BT, Nrf2 inhibitor) or Zine Protoporphyrin (Znpp, HO-1 inhibitor) receded the anti-inflammatory ability of LXA4.

Conclusions

LXA4 plays a protective role in A. fumigatus-stimulated HCECs by inhibiting the expression of pro-inflammatory mediators through the Nrf2/HO-1 signaling pathway.

Lipoxin alleviates oxidative stress: a state-of-the-art review

OBJECTIVE

This review aims to summarize the capability of lipoxin in regulating oxidative stress.

BACKGROUND

Oxidative stress is defined as an imbalance between the production of free radicals and the antioxidant system, and it is associated with the existence of a large number of oxidation products, such as reactive oxygen species (ROS) and reaction nitrogen species (RNS), causing damage to human tissues through immunoinflammatory responses. Therefore, reducing oxidative stress is vital to alleviate pathological damage. Lipoxin, an acronym for lipoxygenase interaction product, is a bioactive autacoid metabolite of arachidonic acid made by various cell types. Previous studies have shown that lipoxin is associated with a variety of biological functions, including anti-inflammatory, regulating immune responses, promoting the repair of damaged cells, etc. The deficiency of lipoxin is a critical pathological mechanism in different diseases. Moreover, the ability of lipoxin to attenuate oxidative stress is noteworthy, thereby protecting the human body from diverse diseases.

METHODS

We searched papers from PubMed database using search terms, such as lipoxin, lipoxin A4, oxidative stress, and other relevant terms.

RESULTS

A total of 103 articles published over the past 20 years were identified for inclusion. We summarized the capability of lipoxin in regulating oxidative stress and mechanism.

CONCLUSION

Lipoxin is provided with a protective role in attenuating oxidative stress.

Possible roles of anti-type II collagen antibody and innate immunity in the development and progression of diabetic retinopathy

The pathogenesis of both diabetic retinopathy (DR) and rheumatoid arthritis (RA) has recently been considered to involve autoimmunity. Serum and synovial fluid levels of anti-type II collagen antibodies increase early after the onset of RA, thus inducing immune responses and subsequent hydrarthrosis and angiogenesis, which resemble diabetic macular edema and proliferative DR (PDR), respectively. We previously reported that DR is also associated with increased serum levels of anti-type II collagen antibodies. Retinal hypoxia in DR may induce pericytes to express type II collagen, resulting in autoantibody production against type II collagen. As the result of blood-retinal barrier disruption, anti-type II collagen antibodies in the serum come into contact with type II collagen around the retinal vessels. A continued loss of pericytes and type II collagen around the retinal vessels may result in a shift of the immune reaction site from the retina to the vitreous. It has been reported that anti-inflammatory M2 macrophages increased in the vitreous of PDR patients, accompanied by the activation of the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome, a key regulator of innate immunity. M2 macrophages promote angiogenesis and fibrosis, which might be exacerbated and prolonged by dysregulated innate immunity.

Lipoxin A4 activates ALX/FPR2 to attenuate inflammation in Aspergillus fumigatus keratitis

PURPOSE

To explore the anti-inflammatory effect of lipoxin A4 (LXA4) in Aspergillus fumigatus (A. fumigatus) keratitis and the underlying mechanisms.

METHODS

In A. fumigatus keratitis mouse models, enzyme-linked immunosorbent assay (ELISA) was used to detect the level of LXA4. Clinical scores were utilized to evaluate fungal keratitis (FK) severity. Fungal load was assessed by plate count. Immunofluorescence staining, HE staining and myeloperoxidase (MPO) assays were carried out to evaluate the neutrophil infiltration and activity. In A. fumigatus infected mouse corneas and inactivated A. fumigatus-stimulated RAW264.7 cells, quantitative real time polymerase chain reaction (qRT-PCR) and ELISA were applied to assess the expression of pro-inflammatory mediators and anti-inflammatory factors.Reactive oxygen species (ROS) was determined by 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) staining in RAW264.7 cells.

RESULTS

LXA4 level was significantly increased in mice with A. fumigatus keratitis. In an A. fumigatus keratitis mouse model, LXA4 treatment alleviated FK severity, reduced fungal load and repressed neutrophil infiltration and activity. Additionally, LXA4 inhibited the expression of pro-inflammatory mediators including IL-1β, TNF-α, IL-6, cyclooxygenase-2 (COX-2), TLR-2, TLR-4, Dectin-1 and iNOS, and promoted the expression of anti-inflammatory factors IL-10 and Arg-1. In RAW264.7 cells, LXA4 receptor/formyl peptide receptor 2 (ALX/FPR2) blockade reversed the anti-inflammatory effect of LXA4. LXA4 suppressed inactivated A. fumigatus induced elevated ROS production in RAW264.7 cells, which was abrogated by ALX/FPR2 antagonist Boc-2.

CONCLUSION

LXA4 ameliorated inflammatory response by suppressing neutrophil infiltration, downregulating the expression of pro-inflammatory mediators and ROS production through ALX/FPR2 receptor in A. fumigatus keratitis.

Therapeutic effects of auricular point acupressure on the recovery of patients after pterygium surgery: A pilot study

BACKGROUND

and purpose: Postoperative pain in the pterygium of the eye seriously affects patient recovery. This study was conducted to assess the efficacy of auricular point acupressure treatment on post-operative recovery in patients after pterygium surgery.

MATERIALS AND METHODS

This was a pilot, randomized controlled study. A total of 60 patients (60 eyes) were randomly assigned to two groups. After pterygium surgery, the auricular group was treated using ear acupressure (acupressure points with Cowherb seeds) and the control group was treated using sham auricular therapy (acupressure points without Cowherb seeds). Both groups were treated for one week. Outcome measures included pain score, corneal epithelial score, best-corrected visual acuity, and recurrence rate.

RESULTS

Fifty-three patients completed the study. The mean pain scores and corneal epithelial scores were significantly reduced over time in the auricular group compared with those in the control group (p < 0.05). The time-group interaction for both pain scores and corneal epithelial scores was significant between the two groups (p < 0.05). Simple main effect analysis showed the mean pain scores in the auricular group were significantly lower at each time point (the first 2-h, the first day, the third day and the first week, p < 0.05) than the control group. Mean corneal epithelial scores of the auricular group were significantly lower on the first day and third day respectively than the control group (p < 0.05). There was no significant difference in the best-corrected visual acuity or recurrence rate between the two groups (p > 0.05).

CONCLUSION

Auricular point acupressure accelerates corneal epithelium reconstruction and suppresses postoperative pain, making it an ideal adjunct treatment for postoperative pterygium recovery.

CLINICAL TRIAL REGISTRATION NUMBER

ChiCTR2000032490 on http://www.chictr.org.cn/.

Pigment Epithelium-Derived Factor Peptide Promotes Corneal Nerve Regeneration: An In Vivo and In Vitro Study

Purpose

To investigate the potential of a pigment epithelium-derived factor (PEDF) peptide 44-mer to promote nerve regeneration in a rabbit corneal nerve injury model to demonstrate its neurotrophic ability in cultivated mouse trigeminal neuron cells.

Methods

Subconjunctival or intrastromal injection of 44-mer on the cornea was performed in a rabbit model of corneal nerve injury created by corneal epithelial debridement. Immunocytochemical analysis (44-mer, anti-tubulin III, SMI312, CD11b, and α-SMA) and in vivo confocal microscopy were performed. Corneal sensation was estimated using a Cochet-Bonnet corneal esthesiometer. Primary cultivated mouse trigeminal neurons were used to examine the in vitro neurotrophic ability of 44-mer. The cellular morphology and the immunocytochemical staining with anti-tubulin III and SMI312 in different concentrations of 44-mer were compared, and a quantitative assessment of neurite outgrowth was performed.

Results

Immunohistochemical staining showed the retention of 44-mer in the corneal stroma for at least 7 days after a single dose of corneal intrastromal injection and promoted corneal nerve regeneration revealed by in vivo confocal microscopy. Corneal esthesiometer demonstrated gradual recovery of the corneal sensation in 44-mer-treated eyes with a lower corneal touch threshold than wounded vehicles and closer to baseline at 3 weeks after corneal injury (P < 0.001). In vitro studies showed a dose-dependent neurotrophic effect of 44-mer in cultivated trigeminal neuron cells.

Conclusions

The 44-mer showed in vivo and in vitro corneal neurotrophic abilities. Our results suggest that intrastromal injection of 44-mer into the corneal stroma may have a potential role in treating diseases related to corneal nerve damage.

The potential of lipid mediator networks as ocular surface therapeutics and biomarkers

In the last twenty years an impressive body of evidence in diverse inflammatory animal disease models and human tissues, has established polyunsaturated fatty acids (PUFA) derived specialized-pro-resolving mediators (SPM), as essential mediators for controlling acute inflammation, immune responses, wound healing and for resolving acute inflammation in many non-ocular tissues. SPM pathways and receptors are highly expressed in the ocular surface where they regulate wound healing, nerve regeneration, innate immunity and sex-specific regulation of auto-immune responses. Recent evidence indicates that in the eye these resident SPM networks are important for maintaining ocular surface health and immune homeostasis. Here, we will review and discuss evidence for SPMs and other PUFA-derived mediators as important endogenous regulators, biomarkers for ocular surface health and disease and their therapeutic potential.

The Role of Specialized Pro-Resolving Mediators in Cystic Fibrosis Airways Disease

Cystic Fibrosis (CF) is a recessive genetic disease due to mutations of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) gene encoding the CFTR chloride channel. The ion transport abnormalities related to CFTR mutation generate a dehydrated airway surface liquid (ASL) layer, which is responsible for an altered mucociliary clearance, favors infections and persistent inflammation that lead to progressive lung destruction and respiratory failure. The inflammatory response is normally followed by an active resolution phase to return to tissue homeostasis, which involves specialized pro-resolving mediators (SPMs). SPMs promote resolution of inflammation, clearance of microbes, tissue regeneration and reduce pain, but do not evoke unwanted immunosuppression. The airways of CF patients showed a decreased production of SPMs even in the absence of pathogens. SPMs levels in the airway correlated with CF patients' lung function. The prognosis for CF has greatly improved but there remains a critical need for more effective treatments that prevent excessive inflammation, lung damage, and declining pulmonary function for all CF patients. This review aims to highlight the recent understanding of CF airway inflammation and the possible impact of SPMs on functions that are altered in CF airways.

Repair Process Impairment by Pseudomonas aeruginosa in Epithelial Tissues: Major Features and Potential Therapeutic Avenues

Epithelial tissues protecting organs from the environment are the first-line of defense against pathogens. Therefore, efficient repair mechanisms after injury are crucial to maintain epithelial integrity. However, these healing processes can be insufficient to restore epithelial integrity, notably in infectious conditions. Pseudomonas aeruginosa infections in cutaneous, corneal, and respiratory tract epithelia are of particular concern because they are the leading causes of hospitalizations, disabilities, and deaths worldwide. Pseudomonas aeruginosa has been shown to alter repair processes, leading to chronic wounds and infections. Because of the current increase in the incidence of multi-drug resistant isolates of P. aeruginosa, complementary approaches to decrease the negative impact of these bacteria on epithelia are urgently needed. Here, we review the recent advances in the understanding of the impact of P. aeruginosa infections on the integrity and repair mechanisms of alveolar, airway, cutaneous and corneal epithelia. Potential therapeutic avenues aimed at counteracting this deleterious impact of infection are also discussed.

Mouse strains and sexual divergence in corneal innervation and nerve regeneration

A variety of mouse strains and sexes are used in studies of corneal wound healing and nerve regeneration. However, there is a gap of knowledge about corneal nerve density and its function in different mouse strains and sexes. In this study, we report a strain divergence of total and substance P (SP) sensory corneal nerves in uninjured mice. The BALB/c mouse showed the highest nerve density, corneal sensitivity, and tear volume followed by CFW and then C57BL/6. No differences were found in total nerves and SP-positive nerves between sexes. After injury damaged the corneal nerves, an important role for mouse strains, biologic sex, and their association to corneal nerve regeneration was identified. All female mice have a faster nerve regeneration rate than males. The molecular mechanism of this sexual divergence involves higher secretion neurotrophic factors in tears, which in turn modulate gene expression in trigeminal ganglion neurons. An important upstream signaling regulator was β-estradiol, and topical treatment with β-estradiol confirmed its function in corneal nerve regeneration. In conclusion, our study shows that the strain and sex of laboratory mice significantly affect the different indicators of corneal innervation and nerve regeneration. Researchers investigating corneal diseases should carefully consider these factors.—Pham, T. L., Kakazu, A., He, J., Bazan, H. E. P. Mouse strains and sexual divergence in corneal innervation and nerve regeneration.

Macrophage-based therapeutic strategies in regenerative medicine

Mounting evidence suggests that therapeutic cell and drug delivery strategies designed to actively harness the regenerative potential of the inflammatory response have great potential in regenerative medicine. In particular, macrophages have emerged as a primary target because of their critical roles in regulating multiple phases of tissue repair through their unique ability to rapidly shift phenotypes. Herein, we review macrophage-based therapies, focusing on the translational potential for cell delivery of ex vivo-activated macrophages and delivery of molecules and biomaterials to modulate accumulation and phenotype of endogenous macrophages. We also review current obstacles to progress in translating basic findings to therapeutic applications, including the need for improved understanding of context-dependent macrophage functions and the myriad factors that regulate macrophage phenotype; potential species-specific differences (e.g. humans versus mice); quality control issues; and the lack of standardized procedures and nomenclature for characterizing macrophages. Looking forward, the inherent plasticity of macrophages represents a daunting challenge for harnessing these cells in regenerative medicine therapies but also great opportunity for improving patient outcomes in a variety of pathological conditions.

Recovery of Corneal Sensitivity and Increase in Nerve Density and Wound Healing in Diabetic Mice After PEDF Plus DHA Treatment

Diabetic keratopathy decreases corneal sensation and tear secretion and delays wound healing after injury. In the current study, we tested the effect of treatment with pigment epithelium-derived factor (PEDF) in combination with docosahexaenoic acid (DHA) on corneal nerve regeneration in a mouse model of diabetes with or without corneal injury. The study was performed in streptozotocin-induced diabetic mice (C57BL/6). Ten weeks after streptozotocin injection, diabetic mice showed significant decreases of corneal sensitivity, tear production, and epithelial subbasal nerve density when compared with age-matched normal mice. After diabetic mice were wounded in the right eye and treated in both eyes with PEDF+DHA for 2 weeks, there was a significant increase in corneal epithelial nerve regeneration and substance P-positive nerve density in both wounded and unwounded eyes compared with vehicle-treated corneas. There also was elevated corneal sensitivity and tear production in the treated corneas compared with vehicle. In addition, PEDF+DHA accelerated corneal wound healing, selectively recruited type 2 macrophages, and prevented neutrophil infiltration in diabetic wounded corneas. These results suggest that topical treatment with PEDF+DHA promotes corneal nerve regeneration and wound healing in diabetic mice and could potentially be exploited as a therapeutic option for the treatment of diabetic keratopathy.

Identification and Profiling of Specialized Pro-Resolving Mediators in Human Tears by Lipid Mediator Metabolomics

Specialized pro-resolving mediators (SPM), e.g. Resolvin D1, Protectin D1, Lipoxin A₄, and Resolvin E1 have each shown to be active in ocular models reducing inflammation. In general, SPMs have specific agonist functions that stimulate resolution of infection and inflammation in animal disease models. The presence and quantity of SPM in human emotional tears is of interest. Here, utilizing a targeted LC-MS-MS metabololipidomics based approach we document the identification of pro-inflammatory (Prostaglandins and Leukotriene B₄) and pro-resolving lipid mediators (D-series Resolvins, Protectin D1, and Lipoxin A₄) in human emotional tears from 12 healthy individuals. SPMs from the Maresin family (Maresin 1 and Maresin 2) were not present in these samples. Principal Component Analysis (PCA) revealed gender differences in the production of specific mediators within these tear samples as the SPMs were essentially absent in these female donors. These results indicate that specific SPM signatures are present in human emotional tears at concentrations known to be bioactive. Moreover, they will help to further appreciate the mechanisms of production and action of SPMs in the eye, as well as their physiologic roles in human ocular disease resolution.

Progress in corneal wound healing

Corneal wound healing is a complex process involving cell death, migration, proliferation, differentiation, and extracellular matrix remodeling. Many similarities are observed in the healing processes of corneal epithelial, stromal and endothelial cells, as well as cell-specific differences. Corneal epithelial healing largely depends on limbal stem cells and remodeling of the basement membrane. During stromal healing, keratocytes get transformed to motile and contractile myofibroblasts largely due to activation of transforming growth factor-β (TGF-β) system. Endothelial cells heal mostly by migration and spreading, with cell proliferation playing a secondary role. In the last decade, many aspects of wound healing process in different parts of the cornea have been elucidated, and some new therapeutic approaches have emerged. The concept of limbal stem cells received rigorous experimental corroboration, with new markers uncovered and new treatment options including gene and microRNA therapy tested in experimental systems. Transplantation of limbal stem cell-enriched cultures for efficient re-epithelialization in stem cell deficiency and corneal injuries has become reality in clinical setting. Mediators and course of events during stromal healing have been detailed, and new treatment regimens including gene (decorin) and stem cell therapy for excessive healing have been designed. This is a very important advance given the popularity of various refractive surgeries entailing stromal wound healing. Successful surgical ways of replacing the diseased endothelium have been clinically tested, and new approaches to accelerate endothelial healing and suppress endothelial-mesenchymal transformation have been proposed including Rho kinase (ROCK) inhibitor eye drops and gene therapy to activate TGF-β inhibitor SMAD7. Promising new technologies with potential for corneal wound healing manipulation including microRNA, induced pluripotent stem cells to generate corneal epithelium, and nanocarriers for corneal drug delivery are discussed. Attention is also paid to problems in wound healing understanding and treatment, such as lack of specific epithelial stem cell markers, reliable identification of stem cells, efficient prevention of haze and stromal scar formation, lack of data on wound regulating microRNAs in keratocytes and endothelial cells, as well as virtual lack of targeted systems for drug and gene delivery to select corneal cells.

Lipoxin A₄-mediated KATP potassium channel activation results in cystic fibrosis airway epithelial repair

The main cause of morbidity and mortality in cystic fibrosis (CF) is progressive lung destruction as a result of persistent bacterial infection and inflammation, coupled with reduced capacity for epithelial repair. Levels of the anti-inflammatory mediator lipoxin A₄ (LXA₄) have been reported to be reduced in bronchoalveolar lavages of patients with CF. We investigated the ability of LXA₄ to trigger epithelial repair through the initiation of proliferation and migration in non-CF (NuLi-1) and CF (CuFi-1) airway epithelia. Spontaneous repair and cell migration were significantly slower in CF epithelial cultures (CuFi-1) compared with controls (NuLi-1). LXA₄ triggered an increase in migration, proliferation, and wound repair of non-CF and CF airway epithelia. These responses to LXA₄ were completely abolished by the ALX/FPR2 receptor antagonist, Boc2 and ALX/FPR2 siRNA. The KATP channel opener pinacidil mimicked the LXA₄ effect on migration, proliferation, and epithelial repair, whereas the KATP channel inhibitor, glibenclamide, blocked the responses to LXA₄. LXA₄ did not affect potassium channel expression but significantly upregulated glibenclamide-sensitive (KATP) currents through the basolateral membrane of NuLi-1 and CuFi-1 cells. MAP kinase (ERK1/2) inhibitor, PD98059, also inhibited the LXA₄-induced proliferation of NuLi-1 and CuFi-1 cells. Finally, both LXA₄ and pinacidil stimulated ERK-MAP kinase phosphorylation, whereas the effect of LXA₄ on ERK phosphorylation was inhibited by glibenclamide. Taken together, our results provided evidence for a role of LXA₄ in triggering epithelial repair through stimulation of the ALX/FPR2 receptor, KATP potassium channel activation, and ERK phosphorylation. This work suggests exogenous delivery of LXA₄, restoring levels in patients with CF, perhaps as a potential therapeutic strategy.