Inhibition of transient receptor potential vanilloid 1 reduces shedding and transmission during Streptococcus pneumoniae co-infection with influenza.

Transmission is the first step for a microorganism to establish colonization in the respiratory tract and subsequent development of infectious disease. Streptococcus pneumoniae is a leading pathogen that colonizes the mucosal surfaces of the human upper respiratory tract and causes subsequent transmission and invasive infections especially in co-infection with influenza A virus. Host factors contributing to respiratory contagion are poorly understood. Transient receptor potential vanilloid (TRPV) channels have various roles in response to microoorganism. Inhibition of TRPV exacerbates invasive infection by Streptococcus pneumoniae, but it is unclear how TRPV channels influence pneumococcal transmission. Here, we describe the effect of inhibition of TRPV1 on pneumococcal transmission. We adopted a TRPV1-deficient infant mouse model of pneumococcal transmission during co-infection with influenza A virus. We also analyzed the expression of nasal mucin or pro-inflammatory cytokines. TRPV1 deficiency attenuated pneumococcal transmission and shedding during co-infection with influenza A virus. TRPV1 deficiency suppressed the expression of nasal mucin. In addition, there were increases in the expression of tumor necrosis factor-α and type I interferon, followed by the suppressed replication of influenza A virus in TRPV1-deficient mice. Inhibition of TRPV1 was shown to attenuate pneumococcal transmission by reducing shedding through the suppression of nasal mucin during co-infection with influenza A virus. Inhibition of TRPV1 suppressed nasal mucin by modulation of pro-inflammatory responses and regulation of replication of influenza A virus. TRPV1 could be a new target in preventive strategy against pneumococcal transmission.

Effects of Ripasudil Hydrochloride on Epithelial Repair in a Mouse Cornea.

PURPOSE: Effect of topical administration of a Rho kinase inhibitor, ripasudil, on epithelial wound healing in a mouse cornea was investigated. Effects of treatment of cultured human corneal epithelial cell (HCEC) line and organ-cultured corneal epithelium with ripasudil on expression of p-ERK was also examined. METHODS: Epithelial defects with a diameter of 2.0 mm were prepared in the central corneas of C57BL/6 mice with or without 1-week travoprost pre-treatment, to which ripasudil or PBS as a control was instilled every 6 h immediately after preparation. The mice eyes were cultured with or without travoprost for 24-hrs. The expression levels of p-ERK in epithelium of mice eyes were compared by immunostaining after further 24-hrs culture with or without ripasudil for 24-hrs. HCEC were cultured with or without ripasudil and processed for examination for proliferation activity and protein expression of p-ERK by either immunostaining or Western blotting. The cells were also treated with or without travoprost for 24-hrs, and were further cultured with or without ripasudil. Expression levels of p-ERK were examined by Western blotting. RESULTS: Ripasudil treatment suppressed post-debridement epithelial healing in association with reduced proliferation activity in peripheral (limbal) epithelium in cornea with or without pre-treatment with travoprost. Ripasudil treatment accelerated p-ERK expression. Ripasudil supplementation upregulated proliferation with increased p-ERK in HCEC. CONCLUSION: Ripasudil treatment promotes wound healing of the mouse corneal epithelium by enhancing cell proliferation on peripheral (limbal) epithelium.

Immunohistochemical findings of lens capsules obtained from patients with dead bag syndrome.

PURPOSE: To investigate the extracellular matrix and cellular components in lens capsules extracted from patients with dead bag syndrome (DBS) through immunohistochemistry. SETTING: Department of Ophthalmology, Wakayama Medical University School of Medicine, Wakayama, Japan, and Department of Ophthalmology and Visual Sciences, John A. Moran Eye Center, University of Utah, Salt Lake City, Utah. DESIGN: Immunohistochemical experimental study. METHODS: 9 capsular bag specimens from DBS cases, as well as 2 control specimens from late-postoperative in-the-bag intraocular lens dislocation cases related to previous vitrectomy, pseudoexfoliation, and blunt trauma were included. They were processed for histopathology; unstained sections were obtained from each one and analyzed by immunohistochemistry targeting collagen type IV, laminin, vimentin, collagen type I, and fibronectin. RESULTS: Immunohistochemistry in DBS showed lens capsule stained for basement membrane components. The outer part of the anterior capsule that was split from the inner part was more markedly stained for type IV collagen as compared with the posterior part. Faint staining for fibrous posterior capsular opacification (PCO) components, for example, collagen type I and fibronectin, was detected in limited areas, but the major portion of the capsule was free from these components. Small spotty vimentin-positive materials, suggesting the presence of cell debris, were also detected in limited samples. CONCLUSIONS: Small amounts of fibrotic PCO components were detected in capsules extracted from patients with DBS, but their major parts were free from PCO components. Current findings suggest small amounts of lens epithelial cells were present after surgery and secreted fibrous components before undergoing cell death process.

Conjunctival Chalasis Should Not be Overlooked: Investigation Into Postoperative Ocular Surface Changes in Involutional Blepharoptosis.

BACKGROUND: Involutional blepharoptosis is common among elderly people. The tightening of eyelids postptosis surgery could potentially increase friction between the eyelid and the ocular surface, but this hypothesis has not yet been substantiated by research. The authors explored the relationship between involutional blepharoptosis surgery and friction-related diseases, namely conjunctivochalasis, lid wiper epitheliopathy, and superior limbic keratoconjunctivitis. METHODS: We conducted a prospective study involving 31 patients who underwent levator advancement for involutional blepharoptosis. Both preoperatively and 6 weeks postoperatively, the authors assessed a range of outcome measures, including margin reflex distance-1, 2, tear film break-up time, superficial punctate keratopathy, inferior conjunctivochalasis, upper lid wiper epitheliopathy, and superior limbic keratoconjunctivitis. RESULTS: Conjunctivochalasis was detected in 18 eyes preoperatively and 20 eyes postoperatively. Lid wiper epitheliopathy was detected in 2 eyes preoperatively and in no eyes postoperatively. Superior limbic keratoconjunctivitis was detected in 2 eyes preoperatively and 1 eye postoperatively. From preoperative to postoperative assessments, conjunctivochalasis worsened in 11 eyes (17.2%), and there were no eyes with worsening lid wiper epitheliopathy or superior limbic keratoconjunctivitis. There was a significant worsening of superficial punctate keratopathy in the group with exacerbated conjunctivochalasis compared with the unchanged group (0.72 vs. 0.12, P =0.0222). The superficial petechial keratopathy in the 6 cases in which there was worsening of both conjunctivochalasis and superficial petechial keratopathy were all located inferiorly in the cornea. CONCLUSIONS: Conjunctivochalasis can worsen following ptosis surgery, potentially leading to an increase in inferior superficial punctate keratopathy. When performing involutional blepharoptosis surgery, surgeons should be mindful of the potential implications of friction-related diseases, particularly conjunctivochalasis.

Impaired healing in an incision wound in corneal stroma in a lumican-null mouse.

PURPOSE: We investigated healing pattern of an incisional wound in corneal stroma of lumican-null (KO) mice. METHODS: C57BL/6 mice (wild-type, WT) and lumican-null (knockout, KO) mice were used. A linear full-thickness incision was produced in one cornea of each mouse. After intervals of healing, the corneas were processed for the following analyses. Histology was employed to measure the distance between each edge of the disrupted Descemet's membrane at the center of the cornea. Immunohistochemistry and real-time RT-PCR were employed to evaluate the expression of wound healing-related components in the tissue. Cultured ocular fibroblasts were obtained from cornea and sclera of WT and KO postnatal day 1 pups. The cells were subjected to examination for cell proliferation and expression of wound healing-related gene products. In vitro gel contraction assay was used to asses cell contractile activity of WT and KO cells. RESULTS: At day 5 of incision, the distance between the disrupted Descemet's membrane was larger in a KO mouse as compared with a WT mouse. Myofibroblast appearance in the wound was suppressed by the loss of lumican. The loss of lumican downregulated TGFß1's effects on mRNA expression of α-smooth muscle actin and collagen Ia1 in cultured ocular fibroblasts. Cell proliferation rate increased in injured stroma, which was further supported by in vitro datum of cell proliferation augmentation by the loss of lumican. Loss of lumican suppressed cell-mediated gel contraction. CONCLUSION: Loss of lumican perturbs the healing of penetrating incision in mouse corneal stroma in association with suppression of myofibroblast generation.

Safety and Pitfalls of Blepharoptosis Surgery in Elderly People.

Background Elderly patients often have complications of blepharoptosis surgery that can result in the appearance or exacerbation of superficial punctate keratopathy (SPK). However, postoperative changes to SPK status have not been previously reported. We used subjective assessment of symptoms and measurement of SPK scale classification to investigate the safety and efficacy of blepharoptosis surgery in elderly patients. Methods Included in this prospective study were 22 patients (44 eyes) with bilateral blepharoptosis that underwent surgery. Patients comprised 8 males and 14 females with a mean (±standard deviation) age of 75.7 ± 8.2 years (range: 61-89). Blepharoptosis surgery consisted of transcutaneous levator advancement and blepharoplasty including resection of soft tissue (skin, subcutaneous tissue, and the orbicularis oculi muscle). Margin reflex distance-1 (MRD-1) measurement, a questionnaire survey of symptoms and SPK scale classification, was administered preoperatively and 3 months postoperatively for evaluation. Results The median MRD-1 was 1 mm preoperatively and 2.5 mm postoperatively, representing a significant postoperative improvement. SPK area and density scores were found to increase when the MRD-1 increase was more than 2.5 mm with surgery. All 10 items on the questionnaire tended have increased scores after surgery, and significant differences were observed in 7 items (poor visibility, ocular fatigue, heavy eyelid, foreign body sensation, difficulty in focusing, headaches, and stiff shoulders). Conclusion Blepharoptosis surgery was found to be a safe and effective way to maintain the increase in MRD-1 within 2.0 mm. Despite the benefits, surgeons must nonetheless be aware that blepharoptosis surgery is a delicate procedure in elderly people.

Engineered Knockout of TRPA1 Inhibits Laser-Induced Choroidal Neovascularization Along With Associated TGFß1 Expression and Neutrophil Infiltration.

We examined the effects of gene ablation and chemical inhibition of transient receptor potential ankyrin 1 (TRPA1) on the growth of experimental argon laser-induced choroidal neovascularization (CNV) in mice. CNV was induced in the eyes of 6- to 8-week-old TRPA1-null (knockout [KO]) and wild-type (WT) mice by argon laser irradiation. Gene expression analysis was performed in laser-injured tissues at days 1 and 3. CNV growth was evaluated at day 14. Reciprocal bone marrow transplantation was performed between each genotype to identify the components responsible for either recipient tissue or bone marrow-derived inflammatory cells. Our results show that laser irradiation successfully induced CNV growth at the site of laser injury. The size of induced CNV was significantly smaller in KO mice than in WT mice at day 14, as determined by angiography with fluorescein isothiocyanate-dextran. Invasion of neutrophils, but not macrophages, was suppressed in association with suppression of the expression of transforming growth factor ß1 and interleukin 6 in laser-irradiated KO tissue. Bone marrow transplantation indicated that the genotype of the recipient mouse, but not of inflammatory cells, is attributable to the KO phenotype. Systemic administration of a TRPA1 antagonist also reduced the CNV in a WT mouse. In conclusion, TRPA1 signaling in local cells is involved in growth of laser-induced CNV. The phenotype was not attributable to vascular endothelial cells and inflammatory cells. Blocking TRPA1 signal may therefore be a potential treatment strategy for CNV-related ocular diseases.

Transforming growth factor beta receptor 2 (Tgfbr2) deficiency in keratocytes results in corneal ectasia.

PURPOSE: We hypothesized that Transforming growth factor beta receptor 2 (Tgfbr2) deletion in keratocyte (Tgfbr2kera-cko), the corneal stroma cell, can result in corneal thinning and generate a potential model for Cornea Ectasia (CE). METHODS: Corneal thickness of Tgfbr2kera-cko and Tgfbr2Ctrl was examined with Optical Coherence Tomography (OCT) at post-natal (P) days 42 and 70, respectively. Histological H&E staining, transmission electron micrograph (TEM), and immunofluorescence staining (IFS) were harnessed to examine corneal cell morphology, proliferation, differentiation, and collagen fibrils. RESULTS: Slit-Lamp revealed that corneas were transparent in both Tgfbr2kera-cko and Tgfbr2Ctrl, however, Tgfbr2kera-cko cornea was 33.5% and 42.9% thinner as compared with those of Tgfbr2Ctrl at P42 and P70, respectively. H&E and semithin section staining with toluidine blue-O confirmed that Tgfbr2kera-cko cornea has a thinner stroma. In contrast, the epithelium in Tgfbr2kera-cko was substantially thicker. The cell proliferation marker Ki67 expression level increased ∼9% in Tgfbr2kera-cko corneal epithelium as compared with that in Tgfbr2Ctrl, however, the Krt14 and Krt12 expression pattern was not obviously changed in Tgfbr2kera-cko corneal epithelium. It was noticed that Col1a1 expression was substantially reduced in Tgfbr2kera-cko as compared with that in Tgfbr2Ctrl. TEM showed that keratocytes were unhealthy and stromal collagen fibril density was significantly reduced in Tgfbr2kera-cko as compared with that in Tgfbr2Ctrl cornea. Moreover, mechanical eye-rubbing on Tgfbr2kera-cko resulted in corneal hydrops and edema. CONCLUSION: Tgfbr2 in keratocytes is indispensable for the corneal stroma at postnatal homeostasis. The cornea phenotype manifested in these Tgfbr2kera-cko mice resembles corneal ectasia disease in humans.

Tenascins and osteopontin in biological response in cornea.

The structural composition, integrity and regular curvature of the cornea contribute to the maintenance of its transparency and vision. Disruption of its integrity caused by injury results in scarring, inflammation and neovascularization followed by losses in transparency. These sight compromising effects is caused by dysfunctional corneal resident cell responses induced by the wound healing process. Upregulation of growth factors/cytokines and neuropeptides affect development of aberrant behavior. These factors trigger keratocytes to first transform into activated fibroblasts and then to myofibroblasts. Myofibroblasts express extracellular matrix components for tissue repair and contract the tissue to facilitate wound closure. Proper remodeling following primary repair is critical for restoration of transparency and visual function. Extracellular matrix components contributing to the healing process are divided into two groups; a group of classical tissue structural components and matrix macromolecules that modulate cell behaviors/activities besides being integrated into the matrix structure. The latter components are designated as matricellular proteins. Their functionality is elicited through mechanisms which modulate the scaffold integrity, cell behaviors, activation/inactivation of either growth factors or cytoplasmic signaling regulation. We discuss here the functional roles of matricellular proteins in mediating injury-induced corneal tissue repair. The roles are described of major matricellular proteins, which include tenascin C, tenascin X and osteopontin. Focus is directed towards dealing with their roles in modulating individual activities of wound healing-related growth factors, e. g., transforming growth factor ß (TGF ß). Modulation of matricellular protein functions could encompass a potential novel strategy to improve the outcome of injury-induced corneal wound healing.

The Roles of Transient Receptor Potential Vanilloid 1 and 4 in Olfactory Regeneration.

Olfactory disorders, which are closely related to cognitive deterioration, can be caused by several factors, including infections, such as COVID-19; aging; and environmental chemicals. Injured olfactory receptor neurons (ORNs) regenerate after birth, but it is unclear which receptors and sensors are involved in ORN regeneration. Recently, there has been great focus on the involvement of transient receptor potential vanilloid (TRPV) channels, which are nociceptors expressed on sensory nerves during the healing of damaged tissues. The localization of TRPV in the olfactory nervous system has been reported in the past, but its function there are unclear. Here, we investigated how TRPV1 and TRPV4 channels are involved in ORN regeneration. TRPV1 knockout (KO), TRPV4 KO, and wild-type (WT) mice were used to model methimazole-induced olfactory dysfunction. The regeneration of ORNs was evaluated using olfactory behavior, histologic examination, and measurement of growth factors. Both TRPV1 and TRPV4 were found to be expressed in the olfactory epithelium (OE). TRPV1, in particular, existed near ORN axons. TRPV4 was marginally expressed in the basal layer of the OE. The proliferation of ORN progenitor cells was reduced in TRPV1 KO mice, which delayed ORN regeneration and the improvement of olfactory behavior. Postinjury OE thickness improved faster in TRPV4 KO mice than WT mice but without acceleration of ORN maturation. The nerve growth factor and transforming growth factor ß levels in TRPV1 KO mice were similar to those in WT mice, and the transforming growth factor ß level was higher than TRPV4 KO mice. TRPV1 was involved in stimulating the proliferation of progenitor cells. TRPV4 modulated their proliferation and maturation. ORN regeneration was regulated by the interaction between TRPV1 and TRPV4. However, in this study, TRPV4 involvement was limited compared with TRPV1. To our knowledge, this is the first study to demonstrate the involvement of TRPV1 and TRPV4 in OE regeneration.

A Glaucoma Patient with an Intraocular Pressure Decrease following Total Gastrectomy and Postoperative Anticancer Treatment.

We herein report a case of glaucoma with an intraocular pressure (IOP) decrease following total gastrectomy (TG) and anticancer treatment for gastric cancer. A 62-year-old male underwent trabeculectomy of the left and right eyes in August 2011 and July 2012, respectively. During the follow-up, IOP of the right eye was 9-12 mmHg (with bimatoprost, dorzolamide, and timolol maleate), and that of the left eye ranged between 14 and 26 mmHg (with bimatoprost, dorzolamide, timolol maleate, and brimonidine tartrate). In December 2014, TG was performed due to gastric cancer. After surgery, the patient received S-1+CDDP, weekly PAC, and CPT-11 therapies. The patient died on March X, 2017. Before TG, the body mass index (BMI) was 29.5 but decreased to 24.8 before the start of the two courses of weekly PAC therapy. IOP of the right eye was 6 mmHg (with bimatoprost), and that of the left eye was 10 mmHg (with bimatoprost, dorzolamide, and brimonidine tartrate), showing decreases. After the initiation of weekly PAC therapy, BMI was approximately 19. IOP of the right eye ranged between 6 and 10 mmHg until the final ophthalmological examination (January 11, 2017), while that of the left eye ranged between 8 and 15 mmHg. In this patient with glaucoma, IOP was not controlled by eye drop treatment, and TG for gastric cancer and postoperative treatment with anticancer drugs resulted in weight loss and a decrease in IOP.

Loss of TRPV4 Cation Channel Inhibition of Macrophage Infiltration and Neovascularization in a Mouse Cornea.

Corneal injury-associated inflammation could induce inward-growing neovascularization from the periphery of the tissue. Such neovascularization could cause stromal opacification and curvature disturbance, and both potentially impair visual function. In this study, we determined the effects of the loss of transient receptor potential vanilloid 4 (TRPV4) expression on the development of neovascularization in the corneal stroma in mice by producing a cauterization injury in the central area of the cornea. New vessels were immunohistochemically labeled with anti-TRPV4 antibodies. TRPV4 gene knockout suppressed the growth of such CD31-labeled neovascularization in association with the suppression of infiltration of macrophages and tissue messenger RNA expression of the vascular endothelial cell growth factor A level. Treatment of cultured vascular endothelial cells with supplementation of HC-067047 (0.1 µM, 1 µM, or 10 µM), a TRPV4 antagonist, attenuated the formation of a tube-like structure with sulforaphane (15 µM, for positive control) that modeled the new vessel formation. Therefore, the TRPV4 signal is involved in injury-induced macrophagic inflammation and neovascularization activity by vascular endothelial cells in a mouse corneal stroma. TRPV4 could be a therapeutic target to prevent unfavorable postinjury neovascularization in the cornea.

Impaired healing of cutaneous wound in a Trpv1 deficient mouse.

Transient Receptor Potential (TRP) ion channels mediate the influx of cations into cells responding to chemical or physical stimuli. TRP vanilloid 1 (TRPV1) regulates cutaneous functions. Its function in cutaneous wound healing, however, has not been clarified. The current study elucidated the role of TRPV1 in cutaneous wound healing of dorsal circular excisional injury using Trpv1-null (KO) and wild type (WT) male/female C57BL/6 mice. Macroscopic observation showed that the remaining cutaneous lesion was significantly larger in KO than that of WT at postoperative days (POD) 7 and 10. Histological analysis showed significantly delayed re-epithelialization in KO at POD7. The number of macrophages in KO and WT similarly returned to the reduced state from POD4 to POD7. Whereas, the number of neutrophils in KO did not significantly return to the reduced state, in contrast to WT. Of note, The H3Cit-labeled NETs (Neutrophil Extracellular Traps) formation of KO was prominently increased both in POD4 and 7. The current results suggest that the loss of TRPV1 induces prolonged neutrophilic inflammation and NETs formation, retarding murine cutaneous wound healing in vivo. This study provides a possible link with TRPV1 and neutrophilic regulation in cutaneous wound healing.

Delayed regression of laser-induced choroidal neovascularization in TNFα-null mice.

We investigated the effects of lacking TNFα on the development and regression of Argon-laser-induced choroidal neovascularization (CNV) in mice. We lasered ocular fundus for induction of CNV in both wild-type (WT) and TNFα-null (KO) mice. Fluorescence angiography was performed to examine the size of CNV lesions. Gene expression pattern of wound healing-related components was examined. The effects of exogenous TNFα on apoptosis of human retinal microvascular endothelial cells (HRMECs) and on the tube-like structure of the cells were investigated in vitro. The results showed that Argon-laser irradiation-induced CNV was significantly larger in KO mice than WT mice on Day 21, but not at other timepoints. Lacking TNFα increased neutrophil population in the lesion. The distribution of cleaved caspase3-labelled apoptotic cells was more frequently observed in the laser-irradiated tissue in a WT mouse as compared with a KO mouse. Exogenous TNFα induced apoptosis of HRMECs and accelerated regression of tube-like structure of HRMECs in cell culture. Taken together, TNFα gene knockout delays the regression of laser-induced CNV in mice. The mechanism underlying the phenotype might include the augmentation of neutrophil population in the treated tissue and attenuation of vascular endothelial cell apoptosis.

Study to the Effect of Involutional Blepharoptosis Surgery Using Objective and Subjective Parameters.

Background We investigate the effect of involutional blepharoptosis (IB) surgery based on dry eye symptoms by analysis using objective and subjective measures. Methods We recorded various parameters from patients that underwent levator advancement surgery for IB, totaling 125 eyes (total 65 patients, 5 unilateral, 60 bilateral). Subjective assessment comprised a questionnaire on dry eye-related quality of life score (DEQS), a summary score calculated from DEQS, and six-grade evaluation, the patient's own measure of eye comfort. Objective assessment comprised marginal-reflex distance-1 (MRD-1), measurement of tear film breakup time, and superficial keratopathy (SPK) existence by slit lamp microscope. Results Subjective assessments showed that IB patients had improvement of dry eye symptoms and eye comfort when surgery increased MRD-1. On the other hand, objective assessments showed that the presence of SPK is suspected when the postoperative MRD-1 level is 3 mm or higher. Conclusion IB surgery must not only increase MRD-1 value, but also to perform maintenance of the appropriate ocular surface condition. From our parameters, we suggest postoperative MRD-1 value should be maintained at < 3 mm to safe and effective of IB surgery.

Anomaly of cornea and ocular adnexa in spinster homolog 2 (Spns2) knockout mice.

Spinster 2 (Spns2) is a transporter that pumps sphingosine-1-phosphate (S1P), a bioactive lipid mediator synthesized in the cytoplasm, out of cells into the inter cellular space. S1P is a signal that modulates cellular behavior during embryonic development, inflammation and tissue repair, etc. A Spns2-null (KO) mouse is born with failure of eyelid closure (eyelid-open-at birth; EOB) and develop corneal fibrosis in adulthood. It remains elusive whether corneal lesion is caused by exposure to keratitis (lagophthalmos) of EOB phenotype or the loss of Spns2 directly perturbs the corneal tissue morphogenesis and intra-eyelid structures. Therefore, we investigated differences between the cornea and ocular adnexa morphogenesis in KO and wild-type (WT) embryos and adults as well. The loss of Spns2 perturbs cornea morphogenesis during embryonic development as early as E16.5 besides EOB phenotype. Histology showed that the corneal stroma was thinner with less extracellular matrix accumulation, e.g., collagen and keratocan in the KO mouse. Epithelial stratification, expression of keratin 12 and formation of desmosomes and hemidesmosomes were also perturbed in these KO corneas. Lacking Spns2 impaired morphogenesis of the Meibomian glands and of orbicularis oculi muscles. KO glands were labeled for ELOVL4 and PPARγ and were Oil-Red O-positive, suggesting KO acinar cells possessed functionality as the glands. This is the first report on the roles of Spns2 in corneal and Meibomian gland morphogenesis. Corneal tissue destruction in an adult KO mouse might be due to not only lagophthalmos but also to an impaired morphogenesis of cornea, Meibomian glands, and orbicularis oculi muscle.

Lack of transient receptor potential ankyrin 1 (TRPA1) retards cutaneous wound healing in mice: A preliminary study.

Wound healing is an important process in various diseases, and elucidating the underlying mechanism is essential for developing therapeutic strategies. We investigated whether the loss of transient receptor potential ankyrin 1 (TRPA1) affects the cutaneous wound healing process in mice. We assessed the formation of granulation tissue by myofibroblasts and macrophages, re-epithelialization, and related gene expression. TRPA1-null (KO) and wild-type (WT) C57BL/6 mice were used for establishing the wound model. Two round full-thickness excision wounds (diameter, 5.0 mm) were produced in the dorsal skin of mice under general anesthesia. After specific intervals, healing was evaluated using macroscopic observation, histology, immunohistochemistry, and real-time reverse transcription-polymerase chain reaction (RT-PCR). TRPA1 KO retarded the formation of granulation tissue and re-epithelialization in the healing of cutaneous wound. Furthermore, TRPA1 KO suppressed the appearance of myofibroblasts, macrophage infiltration, and mRNA expression of αSMA, F4/80, and Col-1α2. These findings indicate that TRPA1 is required for cutaneous wound healing in mice. The lack of TRPA1 retards macrophage infiltration and the subsequent fibrotic tissue formation, which might further impair the fibrogenic behavior of fibroblasts.