Transforming growth factor-{alpha} enhances corneal epithelial cell migration by promoting EGFR recycling

Tetrahedral framework nucleic acids for improving wound healing

Wounds are one of the most common health issues, and the cost of wound care and healing has continued to increase over the past decade. In recent years, there has been growing interest in developing innovative strategies to enhance the efficacy of wound healing. Tetrahedral framework nucleic acids (tFNAs) have emerged as a promising tool for wound healing applications due to their unique structural and functional properties. Therefore, it is of great significance to summarize the applications of tFNAs for wound healing. This review article provides a comprehensive overview of the potential of tFNAs as a novel therapeutic approach for wound healing. In this review, we discuss the possible mechanisms of tFNAs in wound healing and highlight the role of tFNAs in modulating key processes involved in wound healing, such as cell proliferation and migration, angiogenesis, and tissue regeneration. The targeted delivery and controlled release capabilities of tFNAs offer advantages in terms of localized and sustained delivery of therapeutic agents to the wound site. In addition, the latest research progress on tFNAs in wound healing is systematically introduced. We also discuss the biocompatibility and biosafety of tFNAs, along with their potential applications and future directions for research. Finally, the current challenges and prospects of tFNAs are briefly discussed to promote wider applications.

Natural Product Baohuoside I Impairs the Stability and Membrane Location of MRP2 Reciprocally Regulated by SUMOylation and Ubiquitination in Hepatocytes

Epimedii Folium (EF) is a botanical dietary supplement to benefit immunity. Baohuoside I (BI), a prenylated flavonoid derived from EF, has exhibited the cholestatic risk before. Here, the mechanism of BI on the stability and membrane localization of liver MRP2, a bile acid exporter in the canalicular membrane of hepatocytes, was investigated. The fluorescent substrate of MRP2, CMFDA was accumulated in sandwich-cultured primary mouse hepatocytes (SCH) under BI stimulation, followed by reduced membrane MRP2 expression. BI triggered MRP2 endocytosis associated with oxidative stress via inhibition of the NRF2 signaling pathway. Meanwhile, BI promoted the degradation of MRP2 by reducing its SUMOylation and enhancing its ubiquitination level. Co-IP and fluorescence colocalization experiments all proved that MRP2 was a substrate protein for SUMOylation for SUMO proteins. CHX assays showed that SUMO1 prolonged the half-life of MRP2 and further increased its membrane expression, which could be reversed by UBC9 knockdown. Correspondingly, MRP2 accumulated in the cytoplasm by GP78 knockdown or under MG132 treatment. Additionally, the SUMOylation sites of MRP2 were predicted by the algorithm, and a conversion of lysines to arginines at positions 940 and 953 of human MRP2 caused its decreased stability and membrane location. K940 was further identified as the essential ubiquitination site for MRP2 by an in vitro ubiquitination assay. Moreover, the decreased ubiquitination of MRP2 enhanced the SUMOylation MRP2 and vice versa, and the crosstalk of these two modifiers could be disrupted by BI. Collectively, our findings indicated the process of MRP2 turnover from the membrane to cytoplasm at the post-translational level and further elucidated the novel toxicological mechanism of BI.

A dipyridophenazine Ni(II) dithiolene complex as a dual-acting cancer phototherapy agent activatable within the phototherapeutic window

A combination of photodynamic therapy (PDT) and photothermal therapy (PTT) within the phototherapeutic window (600-900 nm) can lead to significantly enhanced therapeutic outcomes, surpassing the efficacy observed with PDT or PTT alone in cancer phototherapy. Herein, we report a novel small-molecule mixed-ligand Ni(II)-dithiolene complex (Ni-TDD) with a dipyridophenazine ligand, demonstrating potent red-light PDT and significant near-infrared (NIR) light mild-temperature PTT activity against cancer cells and 3D multicellular tumour spheroids (MCTSs). The four-coordinate square planar complex exhibited a moderately intense absorption band (ε ∼ 3700 M-1cm-1) centered around 900 nm and demonstrated excellent dark and photostability in an aqueous phase. Ni-TDD induced a potent red-light (600-720 nm) PDT effect on HeLa cancer cells (IC50 = 1.8 μM, photo irritation factor = 44), triggering apoptotic cell death through efficient singlet oxygen generation. Ni-TDD showed a significant intercalative binding affinity towards double-helical calf thymus DNA, resulting in a binding constant (Kb) ∼ 106 M-1. The complex induced mild hyperthermia and exerted a significant mild-temperature PTT effect on MDA-MB-231 cancer cells upon irradiation with 808 nm NIR light. Simultaneous irradiation of Ni-TDD-treated HeLa MCTSs with red and NIR light led to a remarkable synergistic inhibition of growth, exceeding the effects of individual irradiation, through the generation of singlet oxygen and mild hyperthermia. Ni-TDD displayed minimal toxicity towards non-cancerous HPL1D and L929 cells, even at high micromolar concentrations. This is the first report of a Ni(II) complex demonstrating red-light PDT activity and the first example of a first-row transition metal complex exhibiting combined PDT and PTT effects within the clinically relevant phototherapeutic window. Our findings pave the way for designing and developing metal-dithiolene complexes as dual-acting cancer phototherapy agents using long wavelength light for treating solid tumors.

Protective effect of pituitary adenylate cyclase activating polypeptide in diabetic keratopathy

Diabetic keratopathy (DK) is the major complication of the cornea characterizing diabetes-affected patients. This ocular pathology is correlated with the hyperglycemic state leading to delayed corneal wound healing and recurrent corneal ulcers. Pituitary adenylate cyclase-activating polypeptide (PACAP) is a neuropeptide with widespread distribution throughout the body, and exerting cytoprotective effects in the neural and non-neuronal parts of the eye, including the cornea. The purpose of the present study was to investigate whether changes in PACAP expression can concur for delayed epithelial wound healing in diabetic cornea and whether the protective effect of the peptide could be mediated through the activation of the EGFR signaling pathway, which has been reported to be impaired in DK. Expression and distribution of PACAP, PAC1R, and EGFR were investigated through immunohistochemistry analysis in the cornea of normal and diabetic rats. The role of the peptide on wound healing during DK was evaluated in an in vitro model represented by rabbit corneal epithelial cells grown in high glucose conditions. Western blotting and immunofluorescence analysis were used to examine the ability of PACAP to induce the activation of the EGFR/ERK1/2 signaling pathway. Our results showed that in diabetic cornea the expression of PACAP, PAC1R, and EGFR is drastically reduced. The treatment with PACAP via PAC1R activation enhanced cell viability and corneal epithelium wound healing in cells grown under high glucose conditions. Furthermore, both EGFR and ERK1/2 signaling was induced upon the peptide treatment. Overall, our results showed the trophic efficiency of PACAP for enhancing the corneal epithelium re-epithelialization suggesting that the peptide could be beneficially valuable as a treatment for DK.

Modulating Growth Factor Receptor Signaling to Promote Corneal Epithelial Homeostasis

The corneal epithelium is the first anatomical barrier between the environment and the cornea; it is critical for proper light refraction onto the retina and prevents pathogens (e.g., bacteria, viruses) from entering the immune-privileged eye. Trauma to the highly innervated corneal epithelium is extremely painful and if not resolved quickly or properly, can lead to infection and ultimately blindness. The healthy eye produces its own growth factors and is continuously bathed in tear fluid that contains these proteins and other nutrients to maintain the rapid turnover and homeostasis of the ocular surface. In this article, we review the roles of growth factors in corneal epithelial homeostasis and regeneration and some of the limitations to their use therapeutically.

An integrated mechanistic and data-driven computational model predicts cell responses to high- and low-affinity EGFR ligands

The biophysical properties of ligand binding heavily influence the ability of receptors to specify cell fates. Understanding the rules by which ligand binding kinetics impact cell phenotype is challenging, however, because of the coupled information transfers that occur from receptors to downstream signaling effectors and from effectors to phenotypes. Here, we address that issue by developing an integrated mechanistic and data-driven computational modeling platform to predict cell responses to different ligands for the epidermal growth factor receptor (EGFR). Experimental data for model training and validation were generated using MCF7 human breast cancer cells treated with the high- and low-affinity ligands epidermal growth factor (EGF) and epiregulin (EREG), respectively. The integrated model captures the unintuitive, concentration-dependent abilities of EGF and EREG to drive signals and phenotypes differently, even at similar levels of receptor occupancy. For example, the model correctly predicts the dominance of EREG over EGF in driving a cell differentiation phenotype through AKT signaling at intermediate and saturating ligand concentrations and the ability of EGF and EREG to drive a broadly concentration-sensitive migration phenotype through cooperative ERK and AKT signaling. Parameter sensitivity analysis identifies EGFR endocytosis, which is differentially regulated by EGF and EREG, as one of the most important determinants of the alternative phenotypes driven by different ligands. The integrated model provides a new platform to predict how phenotypes are controlled by the earliest biophysical rate processes in signal transduction and may eventually be leveraged to understand receptor signaling system performance depends on cell context.

One-sentence summary

Integrated kinetic and data-driven EGFR signaling model identifies the specific signaling mechanisms that dictate cell responses to EGFR activation by different ligands.

Oral Administration of Vitamin D3 Prevents Corneal Damage in a Knock-Out Mouse Model of Sjögren's Syndrome

BACKGROUND

Vitamin D deficiency has been associated with dry eye development during Sjögren's syndrome (SS). Here, we investigated whether repeated oral vitamin D3 supplementation could prevent the corneal epithelium damage in an SS mouse model.

METHODS

30 female mouse knock-out for the thrombospondin 1 gene were randomized (six per group) in untreated mice euthanized at 6 weeks as negative control (C-) or at 12 weeks as the positive control for dry eye (C+). Other mice were sacrificed after 6 weeks of oral vitamin D3 supplementation in the drinking water (1000, 8000, and 20,000 IU/kg/week, respectively).

RESULTS

The C+ mice showed alterations in their corneal epithelial morphologies and thicknesses (p < 0.01 vs. C-), while the mice receiving 8000 (M) and 20,000 (H) IU/kg/week of vitamin D3 showed preservation of the corneal epithelium morphology and thickness (p < 0.01 vs. C+). Moreover, while the C+ mice exhibited high levels and activity of corneal tumor necrosis factor alpha converting enzyme (TACE), neovascularization and fibrosis markers; these were all reduced in the M and H mice.

CONCLUSIONS

Oral vitamin D3 supplementation appeared to counteract the negative effect of TACE on corneal epithelium in a mouse model of SS-associated dry eye.

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.

Equine Umbilical Cord Serum Composition and Its Healing Effects in Equine Corneal Ulceration

Background

Human autologous serum (AS) and umbilical cord serum (UCS) both contain growth and neurotrophic factors that promote corneal healing.

Aim

Our objectives were to compare equine AS and UCS cytokine and growth factor profiles and to assess the safety and clinical feasibility of the therapeutic use of UCS eye drops in cases of spontaneous complex ulcers.

Study Design

Prospective clinical trial.

Methods

Vitamin A insulin growth factor, platelet-derived growth factor-BB, transforming growth factor (TGF)-β1 (enzyme-linked immunosorbent assay), interleukin (IL)-1β, IL-6, interferon-γ, and monocyte chemoattractant protein 1 concentrations were determined in 10 AS collected from different horses and 10 UCS sampled at delivery. Six client-owned horses presenting with complex non-healing corneal defects of >5 mm² were included in a clinical trial and treated with conventional therapy and conditioned UCS drops for 8–15 days. Ulcer surface and time to complete epithelialization were recorded.

Results

Median concentrations of vitamin A, insulin growth factor, and platelet-derived growth factor-BB were not significantly different in AS compared with UCS (respectively, 14.5 vs. 12.05 μg/ml; 107.8 vs. 107.3 pg/ml; and 369.1 vs. 924.2 pg/ml). TGF-β1 median concentration in UCS was significantly higher than in AS (3,245 vs. 2571pg/ml) (p = 0.04). IL-1β, IL-6, interferon-γ, and monocyte chemoattractant protein 1 concentrations were variable in AS and undetectable in UCS. The corneal median ulcerative area was 37.2 mm² (6.28–57.14 mm²) and had a duration of 4–186 days (median 19 days). All lesions healed within 13–42 days (median 17 days). No adverse effects nor recurrences within 1 month were noticed.

Limitations

The sample size was small. Spontaneous corneal epithelial defects presented with variable clinical characteristics. There were no age-matched control horses to assess corneal healing time and rate.

Conclusion and Clinical Significance

Equine UCS may be beneficial, as it contains no pro-inflammatory cytokines and a greater concentration of TGF-β1 compared with AS. Topical UCS appears safe and may potentially be used as adjunctive therapy for equine complex non-healing ulcers.

Wound healing of the corneal epithelium: a review

The corneal epithelium (CE) forms the outermost layer of the cornea. Despite its thickness of only 50 μm, the CE plays a key role as an initial barrier against any insults to the eye and contributes to the light refraction onto the retina required for clear vision. In the event of an injury, the cornea is equipped with many strategies contributing to competent wound healing, including angiogenic and immune privileges, and mechanotransduction. Various factors, including growth factors, keratin, cytokines, integrins, crystallins, basement membrane, and gap junction proteins are involved in CE wound healing and serve as markers in the healing process. Studies of CE wound healing are advancing rapidly in tandem with the rise of corneal bioengineering, which employs limbal epithelial stem cells as the primary source of cells utilizing various types of biomaterials as substrates.

Epidermal Growth Factor Receptor Expression in the Corneal Epithelium

A properly functioning cornea is critical to clear vision and healthy eyes. As the most anterior portion of the eye, it plays an essential role in refracting light onto the retina and as an anatomical barrier to the environment. Proper vision requires that all layers be properly formed and fully intact. In this article, we discuss the role of the epidermal growth factor receptor (EGFR) in maintaining and restoring the outermost layer of the cornea, the epithelium. It has been known for some time that the addition of epidermal growth factor (EGF) promotes the restoration of the corneal epithelium and patients using EGFR inhibitors as anti-cancer therapies are at increased risk of corneal erosions. However, the use of EGF in the clinic has been limited by downregulation of the receptor. More recent advances in EGFR signaling and trafficking in corneal epithelial cells have provided new insights in how to overcome receptor desensitization. We examine new strategies for overcoming the limitations of high ligand and receptor expression that alter trafficking of the ligand:receptor complex to sustain receptor signaling.

Phenotypic changes on central nervous system (CNS) tumor cell lines cultured in vitro 2D and 3D models and treated with cisplatin

Despite aggressive therapy, most patients with brain tumors present disease relapse due to the cellular and molecular nature of these tumors. One of the models that best explains the heterogeneity observed in CNS tumors is the presence of cancer stem cells (CSCs). In this paper, we evaluated platinum-based response in brain tumor U-87 MG, LN-18, and KELLY cell lines cultured in monolayer (2D) and neurosphere (CSC enrichment- 3D) models. We evaluated mRNA expression of heat shock proteins (HSPA1A, HSPB1, HSPA1AL, TRAP1, and HSPD1), and DNA repair gene ERCC1. Changes in cell cycle and glycosylation profile were assessed by flow cytometry. After treatment with cisplatin, we found that the mRNA expression of HSPs markedly increased in the U-87 MG and LN-18 neurosphere cells. In KELLY monolayer cells, cisplatin induced upregulation of all genes. In KELLY neurosphere cells, only the HSPA1A, HSPB1, TRAP1, and HSPD1 genes were upregulated. The proportion of cells in the G₀/G₁ phase was significantly higher in U-87 MG neurosphere cisplatin-treated cells. A trend towards a greater proportion of cells in the S phase of U-87 MG monolayer cisplatin-treated cells was also observed. On the other hand, a significant decrease in the number of cells in the S phase and an increase in G₂/M was observed in LN-18 monolayer cisplatin-treated cells. Glycosylation analysis using lectins showed a higher surface binding for PNA in the U-87 MG treated monolayer and a lower binding for Concanavalin A in the treated neurospheres. The binding of Isolectin GS-IB4, GSII, and SBA in KELLY monolayer cisplatin-treated cells was lower whereas the proportion of cells labeled with Concanavalin A was higher. In the KELLY neurosphere cisplatin-treated cells, the binding of Concanavalin A was lower than nontreated cells. Thus, our findings strongly supported the idea that definitions of phenotypic characteristics may help to establish better therapeutic strategies for brain tumors.

Canonical NF-κB signaling maintains corneal epithelial integrity and prevents corneal aging via retinoic acid

Disorders of the transparent cornea affect millions of people worldwide. However, how to maintain and/or regenerate this organ remains unclear. Here, we show that Rela (encoding a canonical NF-κB subunit) ablation in K14+ corneal epithelial stem cells not only disrupts corneal regeneration but also results in age-dependent epithelial deterioration, which triggers aberrant wound-healing processes including stromal remodeling, neovascularization, epithelial metaplasia, and plaque formation at the central cornea. These anomalies are largely recapitulated in normal mice that age naturally. Mechanistically, Rela deletion suppresses expression of Aldh1a1, an enzyme required for retinoic acid synthesis from vitamin A. Retinoic acid administration blocks development of ocular anomalies in Krt14-Cre; Relaf/f mice and naturally aged mice. Moreover, epithelial metaplasia and plaque formation are preventable by inhibition of angiogenesis. This study thus uncovers the major mechanisms governing corneal maintenance, regeneration, and aging and identifies the NF-κB-retinoic acid pathway as a therapeutic target for corneal disorders.

Proteoglycan 4 (PRG4) expression and function in dry eye associated inflammation

Dry eye disease (DED) affects hundreds of millions of people worldwide. It is characterized by the production of inflammatory cytokines and chemokines as well as damaging matrix metalloproteinases (MMPs) at the ocular surface. While proteoglycan 4 (PRG4), a mucin-like glycoprotein present at the ocular surface, is most well known as a boundary lubricant that contributes to ocular surface integrity, it has been shown to blunt inflammation in various cell types, suggesting a dual mechanism of action. Recently, full-length recombinant human PRG4 (rhPRG4) has been shown to improve signs and symptoms of DED in humans. However, there remains a significant need for basic science research on rhPRG4's biological properties and its potential therapeutic mechanisms of action in treating DED. Therefore, the objectives of this study were to characterize endogenous PRG4 expression by telomerase-immortalized human corneal epithelial (hTCEpi) cells, examine whether exogenous rhPRG4 modulates cytokine and chemokine secretion in response to dry eye associated inflammation (TNFα and IL-1β), explore interactions between rhPRG4 and MMP-9, and understand how experimental dry eye (EDE) in mice affects PRG4 expression. PRG4 secretion from hTCEpi cells was quantified by Western blot and expression visualized by immunocytochemistry. Cytokine/chemokine production was measured by ELISA and Luminex, while rhPRG4's effect on MMP-9 activity, binding, and expression was quantified using an MMP-9 inhibitor kit, surface plasmon resonance, and reverse transcription polymerase chain reaction (RT-PCR), respectively. Finally, EDE was induced in mice, and PRG4 was visualized by immunohistochemistry in the cornea and by Western blot in lacrimal gland lysate. In vitro results demonstrate that hTCEpi cells synthesize and secrete PRG4, and PRG4 secretion is inhibited by TNFα and IL-1β. In response to these pro-inflammatory stresses, exogenous rhPRG4 significantly reduced the stimulated production of IP-10, RANTES, ENA-78, GROα, MIP-3α, and MIG, and trended towards a reduction of MIP-1α and MIP-1β. The hTCEpi cells were also able to internalize fluorescently-labelled rhPRG4, consistent with a mechanism of action that includes downstream biological signaling pathways. rhPRG4 was not digested by MMP-9, and it did not modulate MMP-9 gene expression in hTCEpi cells, but it was able to bind to MMP-9 and inhibited in vitro activity of exogenous MMP-9 in the presence of human tears. Finally, in vivo results demonstrate that EDE significantly decreased immunolocalization of PRG4 on the corneal epithelium and trended towards a reduction of PRG4 in lacrimal gland lysate. Collectively these results demonstrate rhPRG4 has anti-inflammatory properties on corneal epithelial cells, particularly as it relates to mitigating chemokine production, and is an inhibitor of MMP-9 activity, as well as that in vivo expression of PRG4 can be altered in preclinical models of DED. In conclusion, these findings contribute to our understanding of PRG4's immunomodulatory properties in the context of DED inflammation and provide the foundation and motivation for further mechanistic research of PRG4's properties on the ocular surface as well as expanding clinical evaluation of its ability as a multifunctional therapeutic agent to effectively provide relief to those who suffer from DED.

Knockout of c-Cbl slows EGFR endocytic trafficking and enhances EGFR signaling despite incompletely blocking receptor ubiquitylation

Epidermal growth factor receptor (EGFR) activity is necessary and sufficient for corneal epithelial homeostasis. However, the addition of exogenous Epidermal Growth Factor (EGF) does not reliably restore the corneal epithelium when wounded. This is likely due to high levels of endogenous EGF in tear fluid as well as desensitization of the EGFR following ligand stimulation. We hypothesize that preventing receptor downregulation is an alternative mechanism to enhance EGFR signaling and promote the restoration of compromised corneas. Ligand-dependent EGFR ubiquitylation is associated with the targeted degradation of the receptor. In this manuscript, we determine whether knockout of c-Cbl, an E3 ubiquitin ligase that ubiquitylates the EGFR, is sufficient to prolong EGFR phosphorylation and sustain signaling. Using CRISPR/Cas9 gene editing, we generated immortalized human corneal epithelial (hTCEpi) cells lacking c-Cbl. Knockout (KO) cells expressed the other E3 ligases at the same levels as the control cells, indicating other E3 ligases were not up-regulated. As compared to the control cells, EGF-stimulated EGFR ubiquitylation was reduced in KO cells, but not completely abolished. Similarly, EGF:EGFR trafficking was slowed, with a 35% decrease in the rate of endocytosis and a twofold increase in the receptor half-life. This resulted in a twofold increase in the magnitude of EGFR phosphorylation, with no change in duration. Conversely, Mitogen Activating Protein Kinase (MAPK) phosphorylation did not increase in magnitude but was sustained for 2-3 h as compared to control cells. We propose antagonizing c-Cbl will partially alter receptor ubiquitylation and endocytic trafficking but this is sufficient to enhance downstream signaling.

Lipocalin-2 Regulates Epidermal Growth Factor Receptor Intracellular Trafficking

Epidermal growth factor receptor (EGFR) activation and lipocalin-2 (Lcn2) expression are frequently observed in the same pathological contexts, such as cancers or chronic kidney disease (CKD). However, the significance of this association is unknown. Here, we describe the role of Lcn2 in regulating EGFR trafficking. We show that Lcn2 increases EGFR cell surface abundance and is required for transforming growth factor α (TGF-α)-induced EGFR recycling to the plasma membrane and sustained activation. Lcn2 binds to the intracellular domain of EGFR in late endosomal compartments and inhibits its lysosomal degradation. Consistently, Lcn2 enhances EGFR-induced cell migration after TGF-α stimulation. In vivo, Lcn2 gene inactivation prevents EGFR recycling to the plasma membrane in an experimental model of CKD. Remarkably, this is associated with a dramatic decrease of renal lesions. Together, our data identify Lcn2 as a key mediator of EGFR trafficking processes. Hence, therapeutic inhibition of Lcn2 may counteract the deleterious effect of EGFR activation.

Ni(II) curcumin complexes for cellular imaging and photo-triggered in vitro anticancer activity

Nickel(II) complexes [Ni(cur)(L)₂](OAc) (1-3) where L is N,N-donor heterocyclic bases namely 1,10-phenanthroline (phen in 1), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq in 2), dipyrido[3,2-a:2',3'-c]phenazine (dppz in 3) and Hcur is curcumin were prepared, fully characterized and light-induced in vitro anticancer activity studied. Three nickel(II) complexes containing acetylacetonato (Hacac) ligand, viz.[Ni(acac)(L)₂](OAc) (4-6) where L is phen (in 4), dpq (in 5), dppz (in 6) were prepared and used as controls. Complex 4 was structurally characterized by single crystal X-ray diffraction technique, which revealed an octahedral NiN₄O₂ geometry around the metal centre. Complexes 1-3 showed an intense curcumin-based band at ∼440 nm in DMSO-Tris-HCl buffer (pH = 7.2) (1:4 v/v) which masks the nickel based d-d band. The curcumin comlexes (1-3) were redox inactive at the nickel centre, whereas the acetylacetonato complexes (4-6) displayed an irreversible voltammetric response at ∼1.00 V vs. Ag/AgCl reference electrode in DMF. The complexes bind to calf thymus DNA (ct-DNA) with considerable affinity and interacted with human serum albumin (HSA) with moderate affinity. The Ni(II) curcumin complexes display significant in vitro light-induced cytotoxicity in HeLa (human cervical carcinoma) and A549 (lung cancer cells) involving reactive oxygen species (ROS), with very low dark toxicity. The complexes were found to be much less toxic to immortalized lung epithelial normal cells (HPL1D). Confocal microscopic images using complex 2 and 3 showed that they primarily localize in the cytosol of A549 cells. The mechanism of cell death is mainly apoptosis in nature showing arrest of sub-G1 phase of cell cycle progression in A549 cells under visible light exposure and involves significant loss of mitochondrial membrane potential as observed from JC-1 assay.

Excess Transforming Growth Factor-α Changed the Cell Properties of Corneal Epithelium and Stroma

Purpose

This study is to investigate the corneal anomaly caused by excess transforming growth factor-α (TGF-α) during mouse development.

Methods

Bitransgenic Kera^RT/TGF-α mice, generated via cross-mating tetO-TGF-α and Kera^RT mice, were induced to overexpress TGF-α by doxycycline commencing at embryonic day 0 or postnatal day 0 to different developmental stages. Bitransgenic mice with doxycycline induction were defined as TGF-α^ECK mice (TGF-α excess expression by corneal keratocytes). Mouse eyes were examined by hematoxylin and eosin staining, immunofluorescent staining and transmission electron microscopy. Protein and RNA from mouse cornea were subjected to western blotting and real-time quantitative polymerase chain reaction.

Results

In TGF-α^ECK mice, TGF-α overexpression resulted in corneal opacity. Excess TGF-α initially caused corneal epithelial hyperplasia and subsequent epithelium degeneration as the mouse developed, which was accompanied by gradually diminished K12 expression from the periphery of corneal epithelium and increased K13 expression toward the corneal center. Interestingly, K14 was detected in all layers of corneal epithelium of TGF-α^ECK mice, whereas it was limited at basal layer of controls. Transmission electron microscopy showed desmosome loss between corneal epithelial cells of TGF-α^ECK mice. In TGF-α^ECK mice, keratocan expression was abolished; α-SMA expression was increased while expression of Col1a1, Col1a2, and Col5a1 was diminished. Cell proliferation increased in the corneal epithelium and stroma, but not in the endothelium of TGF-α^ECK mice.

Conclusions

Excess TGF-α had detrimental effects on corneal morphogenesis during mouse development in that it changed the cell fate of corneal epithelial cells to assume conjunctival phenotypic expression of K13, and keratocytes to myofibroblast phenotype.

Chronic and acute arsenic exposure enhance EGFR expression via distinct molecular mechanisms

The impacts of acute arsenic exposure (i.e. vomiting, diarrhea, and renal failure) are distinct from those brought about by sustained, low level exposure from environmental sources or drinking of contaminated well water. Chronic arsenic exposure is a risk factor for the development of pulmonary diseases, including lung cancer. How arsenic exposure leads to pulmonary disease is not fully understood. Both acute versus chronic arsenic exposure increase EGFR expression, but do so via distinct molecular mechanisms. BEAS-2B cells were exposed to either acute sodium arsenite (5 μM for 24 h) or chronic sodium arsenite (100 nM for 24 weeks). Cells treated with acute arsenic exhibited a decrease in viability, changes in morphology, and increased mRNA level of BTC. In contrast, during 24 weeks of arsenic exposure, the cells had increased EGFR expression and activity, and increased mRNA and protein levels of TGFα. Further, chronic arsenic treatment caused an increase in cell migration in the absence of exogenous ligand. Elevated TGFα and EGFR expression are features of many non-small cell lung cancers. We propose that lung epithelial cells chronically exposed to low level arsenic increases EGFR signaling via TGFα production to enhance ligand-independent cell migration.

A Systematic Review on Cornea Epithelial-Stromal Homeostasis

INTRODUCTION

This review aims to summarise the role of different cells, genes, proteins and lipid in regulating cornea epithelial-stromal homeostasis.

METHODS

We performed an Entrez PubMed literature search using keywords "human," "cornea," "epithelial," "stromal," "homeostasis," "fibrosis response," and "pathogenesis" on 24th of September 2019, resulting in 35 papers, of which 18 were chosen after filtering for "English language" and "published within 10 years" as well as curation for relevance by the authors.

RESULTS

The 18 selected papers showed that corneal epithelial cells, fibroblasts and telocytes, together with genes such as Klf4, Pax6 and Id found in the cells, play important roles in achieving homeostasis to maintain corneal integrity and transparency. Proteins classified as pro-fibrotic ligands and anti-fibrotic ligands are responsible for regulating cornea stromal fibrosis and extracellular matrix deposition, thus regulators of scar formation during wound healing. Anti-inflammatory ligands and wound repairing ligands are critical in eliciting protective inflammation and promoting epithelial healing, respectively. Protein receptors located on cellular membrane play a role in maintaining intercellular connections as well as corneal hydration.

DISCUSSION/CONCLUSION

These studies prompt development of novel therapeutic strategies such as tear drops or ointments that target certain proteins to maintain corneal homeostasis. However, more in vitro and in vivo studies are required to prove the effectiveness of exogenous administration of molecules in improving healing outcome. Hence, future investigations of the molecular pathways highlighted in this review will reveal novel therapeutic tools such as gene or cell therapy to treat corneal diseases.

Corneal side effects induced by EGFR-inhibitor antibody-drug conjugate ABT-414 in patients with recurrent glioblastoma: a prospective clinical and confocal microscopy study

Background:

The aim of this study was to prospectively analyse, for the first time worldwide by in vivo clinical confocal microscopy (CCM), corneal side effects secondary to the use of epidermal growth factor receptor (EGFR) inhibitor depatuxizumab mafodotin (ABT-414) in a cohort of patients affected by EGFR-amplified recurrent glioblastoma.

Methods:

Each enrolled patient underwent full ophthalmologic examination including in vivo CCM of the cornea. Each patient was examined at baseline and every 2 weeks during treatment as long as patient conditions allowed it.

Results:

A total of 10 patients were consecutively enrolled. Median follow-up was 5 months. No Common Terminology Criteria for Adverse Events Version 4.0 grade 4 toxicity was documented. Two (20%) grade 3 toxicities were documented at week 8. CCM examination detected in all eyes multiple and diffuse hyperreflective white round spots in the corneal basal epithelial layers (100%), progressive subbasal nerve plexus layer fibres fragmentation followed by full disappearance (100%) and appearance of round cystic structures in the corneal epithelium (100%). All CCM documented side effects reached the peak of prevalence and severity after a median of 3 infusions. After treatment discontinuation, the reversibility of corneal side effects was documented at CCM after a median of 4 weeks.

Conclusion:

ABT-414 toxicity is not only directed to the corneal epithelium, but also to corneal nerves. Side effects are detectable in all treated patients and CCM documents early corneal epithelium and subbasal nerve plexus toxicity, with subsequent progressive restoration after treatment discontinuation. Ocular side effects due to ABT-414 can be manageable.

Distinct Serum and Vitreous Inflammation-Related Factor Profiles in Patients with Proliferative Vitreoretinopathy

INTRODUCTION

Proliferative vitreoretinopathy (PVR), which is regulated by growth factors and cytokines, is the leading cause of failure in vitreoretinal surgery. In this study, we aimed to investigate the role of the human serum and vitreous inflammation-related factors in the development of proliferative vitreoretinopathy (PVR).

METHODS

Blood and vitreous samples were obtained from patients undergoing pars plana vitrectomy. Inflammation-related factors were detected using an immunology multiplex assay on a Luminex® xMAP® platform. Patients with PVR and rhegmatogenous retinal detachment (RRD) were compared with macular hole (MH) or epiretinal membrane (ERM) patients without any other ocular or systemic disease.

RESULTS

Thirty-six serum samples and 34 vitreous samples were obtained. Thirty-one different growth factors and cytokines were detected in serum samples. However, none of the circulating growth factors and cytokines were found to be different from the controls. Ten different growth factors and cytokines were measured in the vitreous samples. The concentration levels of PDGF-AA, TGF-α, VEGF, IL-6, IL-8, and TNFβ were found to have significantly increased in the vitreous of PVR patients.

CONCLUSION

Our study found that none of the circulating inflammation-related factors were changed in PVR or RRD patients, indicating the absence of a system inflammatory biomarkers to predict the development of proliferative vitreoretinopathy. As a supplement to previous research, the concentrations of PDGF-AA, TGF-α, VEGF, IL-6, IL-8, and TNFβ were significantly upregulated in the vitreous of PVR patients. These factors should be considered for preventing PVR.

Protective effect of PACAP-38 on retinal pigmented epithelium in an in vitro and in vivo model of diabetic retinopathy through EGFR-dependent mechanism

Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes. In the last years, several in vivo studies have demonstrated the protective role of pituitary adenylate cyclase-activating peptide (PACAP-38) to counteract several alterations occurring during DR. Recently, different studies have demonstrated that some PACAP-38 effects are mediated by EGFR trans-activation, although no data exist regarding the link between this peptide and EGFR in DR. The aim of the present study has been to investigate whether retinal effect of PACAP-38 against high glucose damage is mediated by EGFR phosphorylation. Diabetes was induced by a single injection of streptozotocin (STZ) in rats. After 1 week, a group of animals was treated with a single intravitreal injection of 100 μM PACAP-38 or saline solution. Immunohistochemistry and western blot analysis have demonstrated that intravitreal injection of PACAP-38 induced p-EGFR over-expression in retina of diabetic rats. Several pathogenic mechanisms may contribute to diabetic retinopathy including BRB alteration. To better clarify the relationship between PACAP-38 and EGFR, we have also carried out a study on ARPE-19 cells, representing a model in vitro of outer BRB. Our results have shown that PACAP-38 treatment improved cell viability in ARPE-19 cells exposed to hyperglycemic/hypoxic insult mimicking tissue microenvironment occurring in DR. Binding to PAC1R, peptide induces EGFR phosphorylation via PKA-signaling cascade stimulation. EGFR trans-activation triggers MAPK/ERK signaling pathway involved in cell survival and proliferation. In conclusion, data have suggested that PACAP-38 acts through EGFR phosphorylation in DR and this effect particularly occurs on RPE layer.

Biomaterials and controlled release strategy for epithelial wound healing

The skin and cornea are tissues that provide protective functions. Trauma and other environmental threats often cause injuries, infections and damage to these tissues, where the degree of injury is directly correlated to the recovery time. For example, a superficial skin or corneal wound may recover within days; however, more severe injuries can last up to several months and may leave scarring. Thus, therapeutic strategies have been introduced to enhance the wound healing efficiency and quality. Although the skin and cornea share similar anatomic structures and wound healing process, therapeutic agents and formulations for skin and cornea wound healing differ in accordance with the tissue and wound type. In this review, we describe the anatomy and epithelial wound healing processes of the skin and cornea, and summarize the therapeutic molecules that are beneficial to the respective regeneration process. In addition, biomaterial scaffolds that inherently possess bioactive properties or modified with therapeutic molecules for topical controlled release and enhanced wound healing efficiency are also discussed.

Tetrahedral Framework Nucleic Acids Promote Corneal Epithelial Wound Healing in Vitro and in Vivo

Poor post-traumatic wound healing can affect the normal function of damaged tissues and organs. For example, poor healing of corneal epithelial injuries may lead to permanent visual impairment. It is of great importance to find a therapeutic way to promote wound closure. Tetrahedral framework nucleic acids (tFNAs) are new promising nanomaterials, which can affect the biological behavior of cells. In the experiment, corneal wound healing is used as an example to explore the effect of tFNAs on wound healing. Results show that the proliferation and migration of human corneal epithelial cells are enhanced by exposure to tFNAs in vitro, possibly relevant to the activation of P38 and ERK1/2 signaling pathway. An animal model of corneal alkali burn is established to further identify the facilitation effect of tFNAs on corneal wound healing in vivo. Clinical evaluations and histological analyses show that tFNAs can improve the corneal transparency and accelerate the re-epithelialization of wounds. Both in vitro and in vivo experiments show that tFNAs can play a positive role in corneal epithelial wound healing.

Photocytotoxic copper(II) complexes of N-salicylyl-l-tryptophan and phenanthroline bases

Four ternary copper(II) complexes of N-salicylyl-l-Tryptophan (Sal-TrpH) and phenanthroline bases of general formula [Cu(Sal-Trp)(L)], where L is 1,10-phenanthroline (phen, 1), dipyrido[3,2-d:2',3'-f]quinoxaline (dpq, 2), dipyrido[3,2-a:2',3'-c]phenazine (dppz, 3) and 2-(anthracen-1-yl)-1H-imidazo[4,5-f][1,10]phenanthroline (aip, 4), were synthesized and fully characterized. The complexes were evaluated for their affinity for biomolecules and photocytotoxic activities. Single crystal X-ray diffraction studies of complex 1 revealed that it has a square pyramidal CuN₃O₂ core with the phenolate oxygen of salicylaldehyde occupying the axial coordination site in the solid state. Complexes 1-4 displayed the Cu(II)-Cu(I) redox couples at ~-0.3 V vs. Ag/AgCl reference electrode in DMF-0.1 M [Buⁿ₄N](ClO₄). A Cu(II)-based weak d-d band ~650 nm and a moderately strong ligand to metal charge transfer band at ~430 nm were observed in DMF-Tris-HCl buffer (pH 7.2) (1:4 v/v). The complexes are efficient binders to calf thymus DNA and model proteins such as bovine serum albumin and lysozyme. They cleave supercoiled plasmid DNA efficiently when exposed to 446 and 660 nm laser radiation. They are cytotoxic to HeLa (human cervical cancer) and MCF-7 (human breast cancer) cells showing significant enhancement of cytotoxicity upon photo-excitation with low energy visible light. The complexes are found to kill cancer cells through generation of reactive oxygen species (ROS) as confirmed by DCFDA (2',7'-dichlorofluorescin diacetate) assay. The apoptotic cell death induced by complex 4 was confirmed by Annexin V-Fluorescein isothiocyanate-Propidium iodide assay. Confocal microscopic images using 4 showed its primary cytosolic localization in the HeLa and MCF-7 cells.

Comparison of growth factor and interleukin content of adult peripheral blood and cord blood serum eye drops for cornea and ocular surface diseases

INTRODUCTION

Various blood-derived products have been proposed for the topical treatment of ocular surface diseases. The aim of the study was to compare the different content of Growth Factors (GFs) and Interleukins (ILs) in peripheral blood (PB-S) and Cord Blood (CB-S) sera.

MATERIALS AND METHODS

Sera were obtained from 105 healthy adult donors (PB-S) and 107 umbilical/placental veins at the time of delivery (CB-S). The levels of epithelial-GF (EGF), fibroblast-GF (FGF), platelet-derived-GF (PDGF), insulin-GF (IGF), transforming-GF alpha (TGF-α,) and beta 1-2-3 (TGF-β1-β2-β3), vascular endothelial-GF (VEGF), nerve-GF (NGF), Interleukin (IL)-1β,IL-4,IL-6,IL-10, and IL-13 were assessed by Bio-Plex Protein Array System (Bio-Rad Laboratories, CA, USA). The Mann-Whitney test for unpaired data was applied to compare GFs and ILs levels in the two sources. The associations among each GF/IL level and the obstetric data for CB-S and hematological characteristics for PB-S were also investigated.

RESULTS

The levels of EGF, TGF-α, TGF-β2, FGF, PDGF, VEGF, NGF, IL-1B, IL-4, IL-6, IL-10, and IL-13 were significantly higher in CB-S compared to PB-S. Conversely, the levels of IGF-1, IGF-2, and TGF-β1 were significantly higher in PB-S. The female sex and the weight of the child showed a significant association in predicting EGF and PDGF levels.

CONCLUSION

A significantly different content in those GFs and ILs was demonstrated in the two blood sources. Since each GF/IL selectively regulates different cellular processes involved in corneal healing, the use of PB-S or CB-S should be chosen on the basis of the cellular mechanism to be promoted in each clinical case.

Human corneal cell culture models for drug toxicity studies

In vivo toxicity and absorption studies of topical ocular drugs are problematic, because these studies involve invasive tissue sampling and toxic effects in animal models. Therefore, different human corneal models ranging from simple monolayer cultures to three-dimensional models have been developed for toxicological prediction with in vitro models. Each system has its own set of advantages and disadvantages. Use of non-corneal cells, inadequate characterization of gene-expression profiles, and accumulation of genomic aberrations in human corneal models are typical drawbacks that decrease their reliability and predictive power. In the future, further improvements are needed for verifying comparable expression profiles and cellular properties of human corneal models with their in vivo counterparts. A rapidly expanding stem cell technology combined with tissue engineering may give future opportunities to develop new tools in drug toxicity studies. One approach may be the production of artificial miniature corneas. In addition, there is also a need to use large-scale profiling approaches such as genomics, transcriptomics, proteomics, and metabolomics for understanding of the ocular toxicity.

Novel mitochondria targeted copper(ii) complexes of ferrocenyl terpyridine and anticancer active 8-hydroxyquinolines showing remarkable cytotoxicity, DNA and protein binding affinity

Mixed-ligand ferrocenyl copper(ii) complexes target the mitochondria of cancer cells showing remarkable cytotoxicity against HeLa and MCF-7 cancer cells while being much less toxic to MCF-10A normal cells.

Caveolin-1 regulates corneal wound healing by modulating Kir4.1 activity

The expression of caveolin-1 (Cav1) in corneal epithelium is associated with regeneration potency. We used Cav1(-/-) mice to study the role of Cav1 in modulating corneal wound healing. Western blot and whole cell patch clamp were employed to study the effect of Cav1 deletion on Kir4.1 current density in corneas. We found that Ba(2+)-sensitive K(+) currents in primary cultured murine corneal epithelial cells (pMCE) from Cav1(-/-) were dramatically reduced (602 pA) compared with those from wild type (WT; 1,300 pA). As a consequence, membrane potential was elevated in pMCE from Cav1(-/-) compared with that from WT (-43 ± 7.5 vs. -58 ± 4.0 mV, respectively). Western blot showed that either inhibition of Cav1 expression or Ba(2+) incubation stimulated phosphorylation of the EGFR. The transwell migration assay showed that Cav1 genetic inactivation accelerated cell migration. The regrowth efficiency of human corneal epithelial cells (HCE) transfected with siRNA-Cav1 or negative control was evaluated by scrape injury assay. With the presence of mitomycin C (10 μg/ml) to avoid the influence of cell proliferation, Cav1 inhibition with siRNA significantly increased migration compared with control siRNA in HCE. This promoting effect by siRNA-Cav1 could not be further enhanced by cotransfection with siRNA-Kcnj10. By using corneal debridement, we found that wound healing was significantly accelerated in Cav1(-/-) compared with WT mice (70 ± 10 vs. 36 ± 3%, P < 0.01). Our findings imply that the mechanism by which Cav-1 knockout promotes corneal regrowth is, at least partially, due to the inhibition of Kir4.1 which stimulates EGFR signaling.

Development of a cell permeable red-shifted CHEF-based chemosensor for Al(3+) ion by controlling PET

A structurally modified quinazoline derivative (L) acts as highly selective chemosensor for Al(3+) ions in DMSO-H2O (1:9, v/v) over the other competitive metal ions. L shows a red shifted fluorescence after the addition of Al(3+) ions and later the further fluorescence enhancement is due to chelation enhanced fluorescence (CHEF) through inhibition of photoinduced electron transfer (PET). This probe (L) detects Al(3+) ions as low as 9nM in DMSO-H2O (1:9, v/v) at biological pH. The non-cytotoxic probe (L) can efficiently detect the intercellular distribution of Al(3+) ions in living cells under a fluorescence microscope to exhibit its sensible applications in the biological systems.

The use of autologous serum for the treatment of ocular surface disease at a Swedish tertiary referral center

PURPOSE

The study aims to describe an intact cohort with mixed ocular surface disease (OSD) treated with autologous serum (AS) eye drops in a tertiary eye center.

PATIENTS AND METHODS

All cases (n=32 eyes, 24 patients) treated with AS for OSD at the Department of Ophthalmology, Sahlgrenska University Hospital, Mölndal, between 2002 and 2013 were included and medical records were reviewed retrospectively.

RESULTS

Mean duration of treatment with 20% AS was 28.3±56.1 (median: 12, range: 3-217) days. The most common indication for AS treatment was a persistent epithelial defect (PED), which was seen in 16 eyes of 14 patients. Mean duration of PED prior to treatment was 19.3±18.9 (median: 10, range: 5-68) days. Complete or partial epithelial healing occurred in nine eyes (56.2%). The remaining seven eyes (44%) did not respond to treatment or data were missing. The second group consisted of nine eyes of five patients with superficial punctate keratitis (SPK) secondary to dry eye syndrome. Complete or partial healing of the epithelium occurred in five eyes (56%), and the remaining four eyes (44%) were lost to follow-up. A third group included five eyes with AS as an adjuvant treatment after corneal perforation, whereas a fourth group consisted of one patient with dry eye after laser-assisted in situ keratomileusis (LASIK).

CONCLUSION

In this cohort, patients with PED or SPK responded well to treatment with AS. Standardized preparation protocols, defined optimal serum concentrations for various indications, and large randomized clinical trials are needed to fully comprehend the role of AS in the treatment of OSD.

Mitochondrial selectivity and remarkable photocytotoxicity of a ferrocenyl neodymium(iii) complex of terpyridine and curcumin in cancer cells

A mixed-ligand neodymium(iii) complex of ferrocene appended terpyridine and curcumin targets the mitochondria and shows remarkable visible-light induced cytotoxicity in HeLa and MCF-7 cancer cells while being much less toxic in dark and to MCF-10A normal cells.

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.

Gene set enrichment analysis of pathways and transcription factors associated with diabetic retinopathy using a microarray dataset

Diabetic retinopathy (DR) is a serious microvascular complication of diabetes, which causes visual disability and blindness. Several studies have used gene expression profiling of DR to identify the key genes involved in this process; however, few studies have focused on the associated pathways and transcription factors (TFs), or on the co-expression patterns at the multiple pathways level. In this study, we employed a microarray dataset from the public database library of the Gene Expression Omnibus (GEO) associated with DR and applied gene set enrichment analysis (GSEA) to this dataset and performed candidate TF selection. As a result, 10 upregulated pathways, including the type I diabetes mellitus and peroxisome proliferator-activated receptor (PPAR) signaling pathways, as well as 59 downregulated pathways, including the ErbB signaling pathway and the mammalian target of rapamycin (mTOR) signaling pathway, were identified as DR‑related pathways. The majority of these pathways have been previously identified, but some were novel. Finally, co-expression networks of related pathways were constructed using the significant core genes and TFs, such as PPARγ and SMAD4. The results of our study may enhance our understanding of the molecular mechanisms associated DR at the genome-wide level.

Stromal-epithelial interaction study: The effect of corneal epithelial cells on growth factor expression in stromal cells using organotypic culture model

Interactions between stromal and epithelial cells play important roles in the development, homeostasis, and pathological conditions of the cornea. Soluble cytokines are critical factors in stromal-epithelial interactions, and growth factors secreted from corneal stromal cells contribute to the regulation of proliferation and differentiation of corneal epithelial cells (CECs). However, the manner in which the expression of growth factors is regulated in stromal cells has not been completely determined. To study stromal-epithelial cell interactions, we used an organotypic culture model. Human or rabbit CECs (HCECs or RCECs) were cultured on amniotic membranes placed on human corneal fibroblasts (HCFs) embedded in a collagen gel. The properties of the organotypic culture were examined by hematoxylin-eosin staining and immunofluorescence. In the organotypic culture, HCECs or RCECs were stratified into two-three layers after five days and five-seven layers after nine days. However, stratification was not observed when the HCECs were seeded on a collagen gel without fibroblasts. K3/K12 were expressed on day 9. The HCF-embedded collagen gels were collected on days 3, 5, or 9 after seeding the RCECs, and mRNA expression of growth factors FGF7, HGF, NGF, EGF, TGF-α, SCF, TGF-β1, TGF-β2, and TGF-β3 were quantified by real-time PCR. mRNA expression of the growth factors in HCFs cultured with RCECs were compared with those cultured without RCECs, as well as in monolayer cultures. mRNA expression of TGF-α was markedly increased in HCFs cultured with RCECs. However, mRNA expression of the TGF-β family was suppressed in HCFs cultured with RCECs. Principal component analysis revealed that mRNA expression of the growth factors in HCFs were generally similar when they were cultured with RCECs. In organotypic cultures, the morphological changes in the CECs and the expression patterns of the growth factors in the stromal cells clearly demonstrated stromal-epithelial cell interactions, and the results suggest that stromal cells and epithelial cells may act in concert in the cornea.

Effect of metal oxidation state on FRET: a Cu(i) silent but selectively Cu(ii) responsive fluorescent reporter and its bioimaging applications

A new structurally characterized cell permeable rhodamine-cinnamaldehyde hybrid (HL) behaves as a Cu(ii) ions selective chemosensor through FRET process which depends on +2 state of copper ion exclusively.

Remarkable visible light-triggered cytotoxicity of mitochondria targeting mixed-ligand cobalt(iii) complexes of curcumin and phenanthroline bases binding to human serum albumin

Co(iii) complexes of curcumin and phenanthroline bases show remarkable visible-light induced cytotoxicity in HeLa cells but are much less toxic in dark and to normal cells. The complexes bind to HSA with significant affinity.

BODIPY appended copper(ii) complexes of curcumin showing mitochondria targeted remarkable photocytotoxicity in visible light

BODIPY-appended copper(ii) complexes of curcumin show a remarkable PDT effect in visible light in HeLa cellsviaapoptosis with mitochondrial localization.

A bio-attuned ratiometric hydrogen sulfate ion selective receptor in aqueous solvent: structural proof of the H-bonded adduct

A new cell permeable quinazoline based receptor (1) behaves as a highly selective chemosensor for HSO₄⁻ ions at nanomolar concentration in aqueous medium by formation of the adduct [LHSO₄]⁻LH⁺·3H₂O confirmed by single crystal X-ray crystallography.

Nexus of signaling and endocytosis in oncogenesis driven by non-small cell lung cancer-associated epidermal growth factor receptor mutants

Epidermal growth factor receptor (EGFR) controls a wide range of cellular processes, and aberrant EGFR signaling as a result of receptor overexpression and/or mutation occurs in many types of cancer. Tumor cells in non-small cell lung cancer (NSCLC) patients that harbor EGFR kinase domain mutations exhibit oncogene addiction to mutant EGFR, which confers high sensitivity to tyrosine kinase inhibitors (TKIs). As patients invariably develop resistance to TKIs, it is important to delineate the cell biological basis of mutant EGFR-induced cellular transformation since components of these pathways can serve as alternate therapeutic targets to preempt or overcome resistance. NSCLC-associated EGFR mutants are constitutively-active and induce ligand-independent transformation in nonmalignant cell lines. Emerging data suggest that a number of factors are critical for the mutant EGFR-dependent tumorigenicity, and bypassing the effects of TKIs on these pathways promotes drug resistance. For example, activation of downstream pathways such as Akt, Erk, STAT3 and Src is critical for mutant EGFR-mediated biological processes. It is now well-established that the potency and spatiotemporal features of cellular signaling by receptor tyrosine kinases such as EGFR, as well as the specific pathways activated, is determined by the nature of endocytic traffic pathways through which the active receptors traverse. Recent evidence indicates that NSCLC-associated mutant EGFRs exhibit altered endocytic trafficking and they exhibit reduced Cbl ubiquitin ligase-mediated lysosomal downregulation. More recent work has shown that mutant EGFRs undergo ligand-independent traffic into the endocytic recycling compartment, a behavior that plays a key role in Src pathway activation and oncogenesis. These studies are beginning to delineate the close nexus between signaling and endocytic traffic of EGFR mutants as a key driver of oncogenic processes. Therefore, in this review, we will discuss the links between mutant EGFR signaling and endocytic properties, and introduce potential mechanisms by which altered endocytic properties of mutant EGFRs may alter signaling and vice versa as well as their implications for NSCLC therapy.

Kcnj10 is a major type of K+ channel in mouse corneal epithelial cells and plays a role in initiating EGFR signaling

We used primary mouse corneal epithelial cells (pMCE) to examine the role of Kcnj10 in determining membrane K(+) conductance and cell membrane potential and in regulating EGF/TGFA release. Western blot, immunostaining, and RT-PCR detected the expression of Kcnj10 in mouse cornea. The single channel recording identified the 20-pS inwardly rectifying K(+) channels in pMCE of WT mice, but these channels were absent in Kcnj10(-/-). Moreover, the whole cell recording demonstrates that deletion of Kcnj10 largely abolished the inward K(+) currents and depolarized the cell membrane K(+) reversal potential (an index of the cell membrane potential). This suggests that Kcnj10 is a main contributor to the cell K(+) conductance and it is pivotal in generating membrane potential in cornea. Furthermore, to test the hypothesis that Kcnj10 expression plays a key role in the stimulation of growth factors release, we employed an immortalized human corneal epithelial cell line (HCE) transfected with siRNA-Kcnj10 or siRNA-control. Levels of TGFA and EGF secreted in the medium were measured by ELISA. Coimmunoprecipitation, biotinylation, and pull-down assay were used to examine the expression of EGFR and the GTP bound form of Rac1 (active Rac1). Downregulation of Kcnj10 activated Rac1 and enhanced EGF/TGFA release, which further contributed to the upregulation of EGFR phosphorylation and surface expression. We conclude that Kcnj10 is a main K(+) channel expressed in corneal epithelial cells and the inhibition of Kcnj10 resulted in depolarization, which in turn induced an EGF-like effect.