MicroRNA‑494 inhibits nerve growth factor‑induced cell proliferation by targeting cyclin D1 in human corneal epithelial cells

Neuropathic Corneal Pain: Tear Proteomic and Neuromediator Profiles, Imaging Features, and Clinical Manifestations

PURPOSE

To investigate the tear proteomic and neuromediator profiles, in vivo confocal microscopy (IVCM) imaging features, and clinical manifestations in neuropathic corneal pain (NCP) patients.

DESIGN

Cross-sectional study.

METHODS

A total of 20 NCP patients and 20 age-matched controls were recruited. All subjects were evaluated by corneal sensitivity, Schirmer test, tear break-up time, and corneal and ocular surface staining, Ocular Surface Disease Index and Ocular Pain Assessment Survey questionnaires were administered, as well as IVCM examinations for corneal nerves, microneruomas, and epithelial and dendritic cells. Tears were collected for neuromediator and proteomic analysis using enzyme-linked immunosorbent assay and data-independent acquisition mass spectrometry.

RESULTS

Burning and sensitivity to light were the 2 most common symptoms in NCP. A total of 188 significantly dysregulated proteins, such as elevated metallothionein-2, creatine kinases B-type, vesicle-associated membrane protein 2, neurofilament light polypeptide, and myelin basic protein, were identified in the NCP patients. The top 10 dysregulated biological pathways in NCP include neurotoxicity, axonal signaling, wound healing, neutrophil degradation, apoptosis, thrombin signaling mitochondrial dysfunction, and RHOGDI and P70S6K signaling pathways. Compared to controls, the NCP cohort presented with significantly decreased corneal sensitivity (P < .001), decreased corneal nerve fiber length (P = .003), corneal nerve fiber density (P = .006), and nerve fiber fractal dimension (P = .033), as well as increased corneal nerve fiber width (P = .002), increased length, total area and perimeter of microneuromas (P < .001, P < .001, P = .019), smaller corneal epithelial size (P = .017), and higher nerve growth factor level in tears (P = .006).

CONCLUSIONS

These clinical manifestations, imaging features, and molecular characterizations would contribute to the diagnostics and potential therapeutic targets for NCP.

Elucidating the mechanism of corneal epithelial cell repair: unraveling the impact of growth factors

The repair mechanism for corneal epithelial cell injuries encompasses migration, proliferation, and differentiation of corneal epithelial cells, and extracellular matrix remodeling of the stromal structural integrity. Furthermore, it involves the consequential impact of corneal limbal stem cells (LSCs). In recent years, as our comprehension of the mediating mechanisms underlying corneal epithelial injury repair has advanced, it has become increasingly apparent that growth factors play a pivotal role in this intricate process. These growth factors actively contribute to the restoration of corneal epithelial injuries by orchestrating responses and facilitating specific interactions at targeted sites. This article systematically summarizes the role of growth factors in corneal epithelial cell injury repair by searching relevant literature in recent years, and explores the limitations of current literature search, providing a certain scientific basis for subsequent basic research and clinical applications.

Limbal Epithelial Stem Cells in the Diabetic Cornea

Continuous replenishment of the corneal epithelium is pivotal for maintaining optical transparency and achieving optimal visual perception. This dynamic process is driven by limbal epithelial stem cells (LESCs) located at the junction between the cornea and conjunctiva, which is otherwise known as the limbus. In patients afflicted with diabetes, hyperglycemia-induced impairments in corneal epithelial regeneration results in persistent epithelial and other defects on the ocular surface, termed diabetic keratopathy (DK), which progressively diminish vision and quality of life. Reports of delayed corneal wound healing and the reduced expression of putative stem cell markers in diabetic relative to healthy eyes suggest that the pathogenesis of DK may be associated with the abnormal activity of LESCs. However, the precise role of these cells in diabetic corneal disease is poorly understood and yet to be comprehensively explored. Herein, we review existing literature highlighting aberrant LESC activity in diabetes, focusing on factors that influence their form and function, and emerging therapies to correct these defects. The consequences of malfunctioning or depleted LESC stocks in DK and limbal stem cell deficiency (LSCD) are also discussed. These insights could be exploited to identify novel targets for improving the management of ocular surface complications that manifest in patients with diabetes.

Increased CYR61 expression activates CCND1/c-Myc pathway to promote nasal epithelial cells proliferation in chronic rhinosinusitis with nasal polyps

PURPOSE

Chronic rhinosinusitis (CRS) with nasal polyps (CRSwNP) is a chronic sinonasal inflammatory disease characterized histologically by hyperplastic nasal epithelium and epithelial cells proliferation. Cysteine-rich angiogenic inducer 61 (CYR61) acts as a positive regulator of cell cycle process. Cyclin D1 (CCND1) and c-Myc play key roles in the processes of cell cycle and cell growth. The purpose of our research was to explore the expression and roles of CYR61, CCND1 and c-Myc in CRSwNP.

METHODS

FeaturePlot and vlnPlot functions embedded in the seurat package (version 4.1.1) of R software (version 4.2.0) were applied to explore the cellular distribution of CYR61, CCND1 and c-Myc in the single-cell RNA sequencing (scRNA-seq) dataset of nasal tissue samples. CYR61, CCND1 and c-Myc immunolabeling and mRNA levels in nasal tissue samples were assessed by immunohistochemistry and real-time PCR. Co-localization of CYR61, CCND1 and c-Myc with basal epithelial cell marker P63 was assayed using double-label immunofluorescence staining. Furthermore, we collected and cultured human nasal epithelial cells (HNEC) to assess the regulation and role of CYR61 in vitro study.

RESULTS

CYR61, CCND1 and c-Myc were primarily expressed by nasal epithelial cells. Significant upregulation of CYR61, CCND1 and c-Myc positive cells and increased levels of CYR61, CCND1 and c-Myc mRNA were found in nasal polyps in comparison to control samples. Of note, CYR61 mRNA and protein levels were altered by SEB, LPS, IFN-γ, IL-13, IL-17A and TGF-β1 in HNEC. In addition, CYR61 intervention could increase CCND1 and c-Myc mRNA and protein levels to promote HNEC proliferation, and siRNA against ITGA2 (si-ITGA2) could reverse CYR61 induced upregulation of CCND1 and c-Myc mRNA and protein levels in HNEC and cell proliferation of HNEC.

CONCLUSIONS

CYR61, CCND1 and c-Myc were primarily expressed by epithelial cells in nasal mucosa. CYR61, CCND1 and c-Myc expression levels were increased in CRSwNP compared with controls. CYR61 could interact with ITGA2 to enhance HNEC proliferation via upregulating CCND1 and c-Myc levels in the HNEC, leading to hyperplastic nasal epithelium in CRSwNP.

A Review of Molecular Interplay between Neurotrophins and miRNAs in Neuropsychological Disorders

Various neurotrophins (NTs), including nerve growth factor, brain-derived neurotrophic factor, neurotrophin-3, and neurotrophin-4, promote cellular differentiation, survival, and maintenance, as well as synaptic plasticity, in the peripheral and central nervous system. The function of microRNAs (miRNAs) and other small non-coding RNAs, as regulators of gene expression, is pivotal for the appropriate control of cell growth and differentiation. There are positive and negative loops between NTs and miRNAs, which exert modulatory effects on different signaling pathways. The interplay between NTs and miRNAs plays a crucial role in the regulation of several physiological and pathological brain procedures. Emerging evidence suggests the diagnostic and therapeutic roles of the interactions between NTs and miRNAs in several neuropsychological disorders, including epilepsy, multiple sclerosis, Alzheimer's disease, Huntington's disease, amyotrophic lateral sclerosis, schizophrenia, anxiety disorders, depression, post-traumatic stress disorder, bipolar disorder, and drug abuse. Here, we review current data regarding the regulatory interactions between NTs and miRNAs in neuropsychological disorders, for which novel diagnostic and/or therapeutic strategies are emerging. Targeting NTs-miRNAs interactions for diagnostic or therapeutic approaches needs to be validated by future clinical studies.

High-concentration atropine induces corneal epithelial cell apoptosis via miR-30c-1/SOCS3

Atropine is an anticholinergic drug widely used in the field of ophthalmology, but its abuse can cause cytotoxicity to the cornea, resulting in blurred vision. This study used cultured human corneal epithelial cells (HCECs) to investigate the mechanism of high-concentration atropine-induced cytotoxicity. HCECs were treated with different concentrations of atropine. The expression levels of microRNA (miR)-30c-1 and suppressor of cytokine signaling 3 (SOCS3) were manipulated in HCECs treated with 0.1% atropine. Cell counting kit-8 assay and flow cytometry were used to assess the viability and apoptosis of HCECs. The relationship between miR-30c-1 and SOCS3 was obtained from an online database and validated using a dual-luciferase reporter assay and RNA immunoprecipitation method. The effect of atropine on the Janus kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling pathway was also investigated. High-concentration atropine inhibited the viability of HCECs and promoted their apoptosis. Moreover, atropine reduced miR-30c-1 expression and increased SOCS3 expression in a dose-dependent manner. It was found that miR-30c-1 targeted SOCS3. Overexpression of miR-30c-1-reduced atropine-induced HCEC cytotoxicity, whereas upregulation of SOCS3 reversed the effects of miR-30c-1 overexpression. High-concentration atropine inhibited activation of the JAK2/STAT3 signaling pathway via miR-30c-1/SOCS3. High-concentration atropine induces HCEC apoptosis by regulating the miR-30c-1/SOCS3 axis and JAK2/STAT3 signaling pathway.

Rescue the retina after the ischemic injury by polymer-mediated intracellular superoxide dismutase delivery

Oxidative stress is a hallmark of the pathophysiogenesis of retinal ischemia. The direct delivery of antioxidant enzymes such as superoxide dismutase (SOD) into retinal cells provides a promising option for the down-regulation of oxidative stress in retinal ischemia, however, efficient intracellular protein delivery remains a major challenge for this application. Here, a boronic acid-rich polymer was used for the intracellular delivery of SOD both in vitro and in vivo. The polymer assembled with SOD into uniform nanoparticles with high binding affinity, and transported the cargo protein into several cell lines with maintained bioactivity and low cytotoxicity. We investigated the intraocular biodistribution, therapeutic efficacy and safety of the SOD nanoformulation in a retinal ischemia/reperfusion (I/R) injury model. After intravitreal injection, the nanoparticles rapidly diffused through the vitreous and penetrated into retinal ganglion cells (RGCs). Compared to free SOD, the nanoformulation exhibited much enhanced therapeutic efficacy with reduced RGC apoptosis and protected retinal function. Enzymatic results confirmed that the SOD nanoformulation reduced malondialdehyde expression and increased glutathione level in the ocular tissues, and thereby down-regulated oxidative stress and prevented RGC loss. Overall, this work offers a new therapeutic option for the treatment of retinal ischemic disorders by direct delivery of antioxidant proteins.

Recent Approaches for Angiogenesis in Search of Successful Tissue Engineering and Regeneration

Angiogenesis plays a central role in human physiology from reproduction and fetal development to wound healing and tissue repair/regeneration. Clinically relevant therapies are needed for promoting angiogenesis in order to supply oxygen and nutrients after transplantation, thus relieving the symptoms of ischemia. Increase in angiogenesis can lead to the restoration of damaged tissues, thereby leading the way for successful tissue regeneration. Tissue regeneration is a broad field that has shown the convergence of various interdisciplinary fields, wherein living cells in conjugation with biomaterials have been tried and tested on to the human body. Although there is a prevalence of various approaches that hypothesize enhanced tissue regeneration via angiogenesis, none of them have been successful in gaining clinical relevance. Hence, the current review summarizes the recent cell-based and cell free (exosomes, extracellular vesicles, micro-RNAs) therapies, gene and biomaterial-based approaches that have been used for angiogenesis-mediated tissue regeneration and have been applied in treating disease models like ischemic heart, brain stroke, bone defects and corneal defects. This review also puts forward a concise report of the pre-clinical and clinical studies that have been performed so far; thereby presenting the credible impact of the development of biomaterials and their 3D concepts in the field of tissue engineering and regeneration, which would lead to the probable ways for heralding the successful future of angiogenesis-mediated approaches in the greater perspective of tissue engineering and regenerative medicine.

Calcitriol inhibits apoptosis via activation of autophagy in hyperosmotic stress stimulated corneal epithelial cells in vivo and in vitro

BACKGROUND

Previously, calcitriol has been demonstrated as a potential therapeutic agent for dry eye, whilst its role on corneal epithelium death remains unclear. This study aims to investigate the relationship between apoptosis and autophagy on dry eye related scenario, as well as the effect of calcitriol and its potential mechanism.

METHODS

In vitro, immortalized human corneal epithelial cells (iHCEC) were cultured in hyperosmotic medium with or without various concentrations of calcitriol and other reagents. In vivo, Wistar rats were applied with benzalkonium chloride to induce dry eye. Then rats were topically treated with calcitriol (10^-6 M) for 14 days. Autophagy flux (LC3B-II and SQSTM1/P62) was examined by western blotting or immunostaining. To test cell apoptosis, western blotting for cleaved caspase-3, Annexin V/PI double staining and TUNEL assay were used. CCK-8 assay was performed to detect the cell viability. Small interfering RNA was used to knock down the expression of vitamin D receptor in iHCECs.

RESULTS

Autophagy activation could protect iHCECs against HS induced apoptosis in vitro, and calcitriol was able to augment autophagy flux via VDR signaling, shown as the remarkably elevated expression of LC3B-II, as well as the declined p62 expression. In vivo results further supported the protective role of calcitriol on corneal epithelium apoptosis through promoting autophagy in dry eye rats.

CONCLUSION

The current study indicated that autophagy was an adaptive change of corneal epithelial cells in response to hyperosmotic stress and calcitriol could prevent cells from apoptosis via further activation of autophagy through VDR pathway.

Nerve growth factor inhibits TLR3-induced inflammatory cascades in human corneal epithelial cells

Background

In herpes simplex epithelial keratitis, excessive TLR3-induced cellular responses after virus infection evoke inflammatory cascades that might be destructive to the host cornea. Nerve growth factor (NGF), a pluripotent neurotrophic factor with immune regulatory effect, was proved to be effective in Herpes simplex keratitis (HSK) treatment, although the detailed mechanisms remain unclear. This study aims to investigate the effects of NGF on modulating inflammatory responses triggered by TLR3 activation in human corneal epithelial cells (HCECs) in vitro.

Methods

HCECs were stimulated with TLR3 agonist, poly(I:C), in the absence or presence of NGF. Cell viability and cytotoxicity were measured by a CCK-8 assay and LDH release assay, respectively. The activation of NF-κB signaling pathway was examined using immunofluorescence staining and western blotting. Levels of proinflammatory cytokines were determined by ELISA or RT-qPCR. ROS generation and 8-OHdG positive cells were examined by a fluorometric analysis.

Results

It was shown that NGF significantly inhibited the generation of proinflammatory cytokines in HCECs triggered by TLR3 activation (P < 0.05), probably via suppressing NF-κB activation. NGF also impeded the upstream signal to initiate NF-κB activation by scavenging ROS by approximately 50% (P < 0.05). In addition, 8-OHdG positive cells were substantially attenuated by NGF treatment (P < 0.01).

Conclusions

Taken together, this study indicates that NGF could inhibit TLR3-induced inflammatory cascades in HCECs, suggesting NGF as a potential therapeutic agent for HSK.