A Structure-Aware Convolutional Neural Network for Automatic Diagnosis of Fungal Keratitis with In Vivo Confocal Microscopy Images.

Fungal keratitis (FK) is a common and severe corneal disease, which is widely spread in tropical and subtropical areas. Early diagnosis and treatment are vital for patients, with confocal microscopy cornea imaging being one of the most effective methods for the diagnosis of FK. However, most cases are currently diagnosed by the subjective judgment of ophthalmologists, which is time-consuming and heavily depends on the experience of the ophthalmologists. In this paper, we introduce a novel structure-aware automatic diagnosis algorithm based on deep convolutional neural networks for the accurate diagnosis of FK. Specifically, a two-stream convolutional network is deployed, combining GoogLeNet and VGGNet, which are two commonly used networks in computer vision architectures. The main stream is used for feature extraction of the input image, while the auxiliary stream is used for feature discrimination and enhancement of the hyphae structure. Then, the features are combined by concatenating the channel dimension to obtain the final output, i.e., normal or abnormal. The results showed that the proposed method achieved accuracy, sensitivity, and specificity of 97.73%, 97.02%, and 98.54%, respectively. These results suggest that the proposed neural network could be a promising computer-aided FK diagnosis solution.

[A case of Stevens-Johnson syndrome with binocular corneal perforation and multiple corneal transplantation which was difficult to control].

The 31-year-old female patient was admitted to the General Hospital of the Chinese People's Liberation Army for 3 days after the corneal transplantation of her right eye for 5 months.Four years ago, the patient developed red eyes, pain, dryness and photophobia after intravenous drip of cefuroxime sodium and metronidazole due to pelvic inflammation, accompanied by high fever, systemic rash and epidermal exfoliation, fingernail peeling, and mucosal ulceration in the eyes and mouth.Later, the patient received systemic hormone shock and point eye treatment in a local hospital, and the dry eyes gradually worsened. Despite continuous artificial tears and bandage mirror treatment, the corneal ulcer perforation in both eyes still occurred successively. After several penetrating keratografts and drug therapy, the ulcer and dissolution could not be prevented. He was admitted to our hospital due to corneal perforation in both eyes.Ophthalmic examination: visual acuity manual/15 cm in the right eye, intraocular pressure T-2, conjunctival sac stenosis, extensive corneal opacity and edema, ulcer about 8 mm, corneal perforation near the corneal limbus about 2 mm×5 mm below.The left eye had no light perception, a central corneal ulcer of about 8 mm, bulge of the posterior elastic layer, no anterior chamber, and atrophy of the eyeball.B-ultrasound showed choroidal detachment of the right eye.On the second day, the patient received right eye intraocular exploration, vitrectomy, ecotopic keratoscleral carrier Boston Ⅱ artificial keratoplasty, glaucoma valve implantation, autogenous ear cartilage implantation, conjunctival occlusion, and left eye lamellar keratoplasty, conjunctival occlusion.Postoperative visual acuity of right eye was -6.50 DS=0.12, intraocular pressure TN, ocular surface was stable.The left eye has no light perception and the ocular surface is stable.

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

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

Conjunctival microvascular responses to anti-inflammatory treatment in patients with dry eye.

PURPOSE: This study characterized conjunctival microvascular morphological and haemodynamic responses after anti-inflammatory treatment in dry eye (DE). MATERIALS AND METHODS: Twenty-five patients with moderate DE (17 females and 8 males aged 48 ± 16 years) who underwent anti-inflammatory therapy (0.1% fluorometholone) and 25 healthy subjects (20 females and 5 males aged 48 ± 17 years) recruited as controls were enrolled. The conjunctival blood flow rate (BFR), blood flow velocity (BFV) and vessel diameter were measured by functional slit-lamp biomicroscopy (FSLB). DE symptoms and signs were assessed. All measurements were performed at baseline and at 30 and 60 days after commencement of treatment. RESULTS: At baseline, the conjunctival BFR, BFV, and vessel diameter were higher in the DE group than in the control group (p < 0.05). The BFR, BFV and corneal fluorescein staining (CFS) scores decreased at 60 days after therapy compared to at baseline and 30 days (all pcorrected < 0.05); Ocular surface diseases index (OSDI), the hyperaemia index (HI) and vessel diameters only showed significant decreases at 30 days. Moreover, significant increases in the noninvasive tear film break-up time (NI-BUT) and Schirmer I test score (ST) were observed. The CFS score correlated positively with BFV (r = 0.46), BFR (r = 0.58) and vessel diameter (r = 0.47). CONCLUSION: This study characterized conjunctival microvascular responses to anti-inflammatory treatment in DE patients. The results suggest that conjunctival BFV and BFR can be used as dynamic markers for treatment efficacy in DE.

Healing characteristics of acellular porcine corneal stroma following therapeutic keratoplasty.

BACKGROUND: Acellular porcine corneal stroma (APCS) has proven to be a promising alternative to traditional corneal grafts. This prospective case series was conducted to further investigate the healing characteristics of APCS following keratoplasty. METHODS: Twenty-seven patients undergoing APCS implantation to treat infectious keratitis were included. The patients were followed up for 12 months after surgery. The main outcome measures included visual acuity, corneal transparency, graft thickness, and cellular and nerve regeneration. RESULTS: In the operated eyes, the best-corrected visual acuity (BCVA, in logarithm of the minimal angle of resolution [logMAR] units) increased from 1.23 ± 0.95 logMAR before surgery to 0.23 ± 0.18 logMAR at 12 months after surgery (P < .001). The contrast sensitivity was still evidently reduced, especially at higher spatial frequencies. Gradual transparency improvement was observed in APCS grafts post-operatively. After implantation, the APCS graft thickness initially increased (day 1 = 592.41 ± 52.69 µm) but then continuously decreased until 3 months after surgery (1 month = 449.26 ± 50.38 µm; 3 months = 359.63 ± 34.14 µm, P < .001). Graft reepithelialization was completed within 1 week. In the in vivo confocal microscopy scans, host keratocytes began to repopulate the APCS grafts between 3 and 6 months post-operatively; subbasal nerve regeneration was only noted in 18.52% (5/27) of the eyes by 12 months after surgery. CONCLUSIONS: Acellular porcine corneal stroma functions as an effective alternative to human corneal tissue in lamellar keratoplasty. However, APCS is somewhat different from fresh human cornea in term of the post-operative healing process, which warrants the attention of both clinicians and patients.

Neurog2 and Ascl1 together regulate a postmitotic derepression circuit to govern laminar fate specification in the murine neocortex.

A derepression mode of cell-fate specification involving the transcriptional repressors Tbr1, Fezf2, Satb2, and Ctip2 operates in neocortical projection neurons to specify six layer identities in sequence. Less well understood is how laminar fate transitions are regulated in cortical progenitors. The proneural genes Neurog2 and Ascl1 cooperate in progenitors to control the temporal switch from neurogenesis to gliogenesis. Here we asked whether these proneural genes also regulate laminar fate transitions. Several defects were observed in the derepression circuit in Neurog2-/-;Ascl1-/- mutants: an inability to repress expression of Tbr1 (a deep layer VI marker) during upper-layer neurogenesis, a loss of Fezf2+/Ctip2+ layer V neurons, and precocious differentiation of normally late-born, Satb2+ layer II-IV neurons. Conversely, in stable gain-of-function transgenics, Neurog2 promoted differentiative divisions and extended the period of Tbr1+/Ctip2+ deep-layer neurogenesis while reducing Satb2+ upper-layer neurogenesis. Similarly, acute misexpression of Neurog2 in early cortical progenitors promoted Tbr1 expression, whereas both Neurog2 and Ascl1 induced Ctip2. However, Neurog2 was unable to influence the derepression circuit when misexpressed in late cortical progenitors, and Ascl1 repressed only Satb2. Nevertheless, neurons derived from late misexpression of Neurog2 and, to a lesser extent, Ascl1, extended aberrant subcortical axon projections characteristic of early-born neurons. Finally, Neurog2 and Ascl1 altered the expression of Ikaros and Foxg1, known temporal regulators. Proneural genes thus act in a context-dependent fashion as early determinants, promoting deep-layer neurogenesis in early cortical progenitors via input into the derepression circuit while also influencing other temporal regulators.

Risk factors influencing survival of acellular porcine corneal stroma in infectious keratitis: a prospective clinical study.

BACKGROUND: A worldwide lack of donor corneas demands the bioengineered corneas be developed as an alternative. The primary objective of the current study was to evaluate the efficacy of acellular porcine corneal stroma (APCS) transplantation in various types of infectious keratitis and identify risk factors that may increase APCS graft failure. METHODS: In this prospective interventional study, 39 patients with progressive infectious keratitis underwent therapeutic lamellar keratoplasty using APCS and were followed up for 12 months. Data collected for analysis included preoperative characteristics, visual acuity, graft survival and complications. Graft survival was evaluated by the Kaplan-Meier method and compared with the log-rank test. RESULTS: The percentage of eyes that had a visual acuity of 20/40 or better increased from 10.3% preoperatively to 51.2% at 12 months postoperatively. Twelve patients (30.8%) experienced graft failure within the follow-up period. The primary reasons given for graft failure was noninfectious graft melting (n = 5), and the other causes included recurrence of primary infection (n = 4) and extensive graft neovascularization (n = 3). No graft rejection was observed during the follow-up period. A higher relative risk (RR) of graft failure was associated with herpetic keratitis (RR = 8.0, P = 0.046) and graft size larger than 8 mm (RR = 6.5, P < 0.001). CONCLUSIONS: APCS transplantation is an alternative treatment option for eyes with medically unresponsive infectious keratitis. Despite the efficacy of therapeutic lamellar keratoplasty with APCS, to achieve a good prognosis, restriction of surgical indications, careful selection of patients and postoperative management must be emphasized. Trial registration Prospective Study of Deep Anterior Lamellar Keratoplasty Using Acellular Porcine Cornea, NCT03105466. Registered 31 August 2016, ClinicalTrails.gov.

Tacrolimus interacts with voriconazole to reduce the severity of fungal keratitis by suppressing IFN-related inflammatory responses and concomitant FK506 and voriconazole treatment suppresses fungal keratitis.

Purpose: To investigate the expression and roles of type I and II interferons (IFNs) in fungal keratitis, as well as the therapeutic effects of tacrolimus (FK506) and voriconazole on this condition. Methods: The mRNA and protein expression levels of type I (IFN-α/ß) and II (IFN-γ) IFNs, as well as of related downstream inflammatory cytokines (interleukin (IL)-1α, IL-6, IL-12, and IL-17), were detected in macrophages, neutrophils, lymphocytes, and corneal epithelial cells (A6(1) cells) stimulated with zymosan (10 mg/ml) for 8 or 24 h. A fungal keratitis mouse model was generated through intrastromal injection of Aspergillus fumigatus, and the mice were then divided into four groups: group I, the PBS group; group II, the voriconazole group; group III, the FK506 group; and group IV, the voriconazole plus 0.05% FK506 group. Corneal damage was evaluated with clinical scoring and histological examination. In addition, the mRNA and protein expression levels of type I (IFN-α/ß) and type II (IFN-γ) IFNs, as well as related inflammatory cytokines, were determined at different time points using quantitative real-time PCR (qRT-PCR) and western blotting. Results: After zymosan stimulation of mouse neutrophils, lymphocytes, macrophages, and A6(1) cells, the IFN mRNA and protein expression levels were markedly increased until 24 h, peaking at 8 h (p<0.001). The mRNA and protein expression levels of inflammatory cytokines (IL-1α, IL-6, IL-12, and IL-17) were also upregulated after zymosan stimulation. Moreover, type I (IFN-α/ß) and type II (IFN-γ) IFN expression levels were increased and positively correlated with the progression of fungal keratitis in vivo. FK506 administered with voriconazole reduced the pathological infiltration of inflammatory cells into the cornea and downregulated the expression levels of IFNs and related inflammatory cytokines. Conclusions: In conclusion, this study demonstrated that type I and II IFN levels were markedly increased in fungal keratitis and that FK506 combined with voriconazole decreased the severity of fungal keratitis by suppressing type I and II IFNs and their related inflammatory responses.

Microvascular abnormalities in dry eye patients.

This study was conducted to evaluate conjunctival blood flow velocities and microvascular network density in patients with dry eye disease (DED). Twenty-five patients with DED and 25 healthy controls were recruited. The microvasculature and microcirculation of the temporal bulbar conjunctiva of the right eyes were assessed using a functional slit-lamp biomicroscope. Vascular variables included blood flow velocity (BFV), blood flow rate (BFR), microvascular network density and vessel diameter. A fractal analysis was performed using the box counting method to measure the fractal dimension (Dbox) representing the vessel density. The bulbar BFV was 0.59 ±â€¯0.09 mm/s in the DED group and 0.47 ±â€¯0.12 in the control group (P < 0.001). BFR was 169.5 ±â€¯1.8 in the DED group compared to the control group (107.2 ±â€¯49.6) (P < 0.001). Dbox was higher in DED patients (1.65 ±â€¯0.04) than controls (1.60 ±â€¯0.07, P < 0.05). Moreover, the vessel diameter was larger in the DED group (21.8 ±â€¯1.8 µm) compared with controls (17.9 ±â€¯2.2 µm, P < 0.001). Dbox was positively related with ocular surface disease index (OSDI) in patients with DED (r = 0.54, P = 0.008). Microvascular alterations were found in the bulbar conjunctiva of DED patients, including increased blood flow velocity, higher vessel density and larger vessel diameter.

Rapid deterioration of Mooren's ulcers after conjunctival flap: a review of 2 cases.

BACKGROUND: Conjunctival flaps are a widely used treatment for numerous corneal ulcers that are caused by microorganismal infections. However, whether it can be performed on immune-mediated corneal ulcers is controversial. CASE PRESENTATION: We present two cases of Mooren's ulcer that were treated using conjunctival flap in an attempt to prevent further corneal perforation at their local hospital. A rapid acceleration in ulcer progression was observed after a conjunctival flap was applied. Ultimately, the two patients underwent corneal transplantation, which required the postoperative use of topical immunosuppressants and resulted in a final cure. In the current report, we also discussed this incorrect surgical choice via a review of conventional interventions that are used to treat Mooren's ulcer. CONCLUSIONS: These two cases demonstrate that keratoplasty combined with topical immunosuppressants is effective in treating Mooren's ulcer. Application of conjunctival flaps or autografting could promote progression of ulceration in Mooren's ulcers.

Zac1 Regulates the Differentiation and Migration of Neocortical Neurons via Pac1.

Imprinted genes are dosage sensitive, and their dysregulated expression is linked to disorders of growth and proliferation, including fetal and postnatal growth restriction. Common sequelae of growth disorders include neurodevelopmental defects, some of which are indirectly related to placental insufficiency. However, several growth-associated imprinted genes are also expressed in the embryonic CNS, in which their aberrant expression may more directly affect neurodevelopment. To test whether growth-associated genes influence neural lineage progression, we focused on the maternally imprinted gene Zac1. In humans, either loss or gain of ZAC1 expression is associated with reduced growth rates and intellectual disability. To test whether increased Zac1 expression directly perturbs neurodevelopment, we misexpressed Zac1 in murine neocortical progenitors. The effects were striking: Zac1 delayed the transition of apical radial glial cells to basal intermediate neuronal progenitors and postponed their subsequent differentiation into neurons. Zac1 misexpression also blocked neuronal migration, with Zac1-overexpressing neurons pausing more frequently and forming fewer neurite branches during the period when locomoting neurons undergo dynamic morphological transitions. Similar, albeit less striking, neuronal migration and morphological defects were observed on Zac1 knockdown, indicating that Zac1 levels must be regulated precisely. Finally, Zac1 controlled neuronal migration by regulating Pac1 transcription, a receptor for the neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP). Pac1 and Zac1 loss- and gain-of-function presented as phenocopies, and overexpression of Pac1 rescued the Zac1 knockdown neuronal migration phenotype. Thus, dysregulated Zac1 expression has striking consequences on neocortical development, suggesting that misexpression of this transcription factor in the brain in certain growth disorders may contribute to neurocognitive deficits. Significance statement: Altered expression of imprinted genes is linked to cognitive dysfunction and neuropsychological disorders, such as Angelman and Prader-Willi syndromes, and autism spectrum disorder. Mouse models have also revealed the importance of imprinting for brain development, with chimeras generated with parthenogenetic (two maternal chromosomes) or androgenetic (two paternal chromosomes) cells displaying altered brain sizes and cellular defects. Despite these striking phenotypes, only a handful of imprinted genes are known or suspected to regulate brain development (e.g., Dlk1, Peg3, Ube3a, necdin, and Grb10). Herein we show that the maternally imprinted gene Zac1 is a critical regulator of neocortical development. Our studies are relevant because loss of 6q24 maternal imprinting in humans results in elevated ZAC1 expression, which has been associated with neurocognitive defects.

RAS/ERK signaling controls proneural genetic programs in cortical development and gliomagenesis.

Neural cell fate specification is well understood in the embryonic cerebral cortex, where the proneural genes Neurog2 and Ascl1 are key cell fate determinants. What is less well understood is how cellular diversity is generated in brain tumors. Gliomas and glioneuronal tumors, which are often localized in the cerebrum, are both characterized by a neoplastic glial component, but glioneuronal tumors also have an intermixed neuronal component. A core abnormality in both tumor groups is overactive RAS/ERK signaling, a pro-proliferative signal whose contributions to cell differentiation in oncogenesis are largely unexplored. We found that RAS/ERK activation levels differ in two distinct human tumors associated with constitutively active BRAF. Pilocytic astrocytomas, which contain abnormal glial cells, have higher ERK activation levels than gangliogliomas, which contain abnormal neuronal and glial cells. Using in vivo gain of function and loss of function in the mouse embryonic neocortex, we found that RAS/ERK signals control a proneural genetic switch, inhibiting Neurog2 expression while inducing Ascl1, a competing lineage determinant. Furthermore, we found that RAS/ERK levels control Ascl1's fate specification properties in murine cortical progenitors--at higher RAS/ERK levels, Ascl1(+) progenitors are biased toward proliferative glial programs, initiating astrocytomas, while at moderate RAS/ERK levels, Ascl1 promotes GABAergic neuronal and less glial differentiation, generating glioneuronal tumors. Mechanistically, Ascl1 is phosphorylated by ERK, and ERK phosphoacceptor sites are necessary for Ascl1's GABAergic neuronal and gliogenic potential. RAS/ERK signaling thus acts as a rheostat to influence neural cell fate selection in both normal cortical development and gliomagenesis, controlling Neurog2-Ascl1 expression and Ascl1 function.

Neurog1 and Neurog2 control two waves of neuronal differentiation in the piriform cortex.

The three-layered piriform cortex, an integral part of the olfactory system, processes odor information relayed by olfactory bulb mitral cells. Specifically, mitral cell axons form the lateral olfactory tract (LOT) by targeting lateral olfactory tract (lot) guidepost cells in the piriform cortex. While lot cells and other piriform cortical neurons share a pallial origin, the factors that specify their precise phenotypes are poorly understood. Here we show that in mouse, the proneural genes Neurog1 and Neurog2 are coexpressed in the ventral pallium, a progenitor pool that first gives rise to Cajal-Retzius (CR) cells, which populate layer I of all cortical domains, and later to layer II/III neurons of the piriform cortex. Using loss-of-function and gain-of-function approaches, we find that Neurog1 has a unique early role in reducing CR cell neurogenesis by tempering Neurog2's proneural activity. In addition, Neurog1 and Neurog2 have redundant functions in the ventral pallium, acting in two phases to first specify a CR cell fate and later to specify layer II/III piriform cortex neuronal identities. In the early phase, Neurog1 and Neurog2 are also required for lot cell differentiation, which we reveal are a subset of CR neurons, the loss of which prevents mitral cell axon innervation and LOT formation. Consequently, mutation of Trp73, a CR-specific cortical gene, results in lot cell and LOT axon displacement. Neurog1 and Neurog2 thus have unique and redundant functions in the piriform cortex, controlling the timing of differentiation of early-born CR/lot cells and specifying the identities of later-born layer II/III neurons.

Neurog2 simultaneously activates and represses alternative gene expression programs in the developing neocortex.

Progenitor cells undergo a series of stable identity transitions on their way to becoming fully differentiated cells with unique identities. Each cellular transition requires that new sets of genes are expressed, while alternative genetic programs are concurrently repressed. Here, we investigated how the proneural gene Neurog2 simultaneously activates and represses alternative gene expression programs in the developing neocortex. By comparing the activities of transcriptional activator (Neurog2-VP16) and repressor (Neurog2-EnR) fusions to wild-type Neurog2, we first demonstrate that Neurog2 functions as an activator to both extinguish Pax6 expression in radial glial cells and initiate Tbr2 expression in intermediate neuronal progenitors. Similarly, we show that Neurog2 functions as an activator to promote the differentiation of neurons with a dorsal telencephalic (i.e., neocortical) identity and to block a ventral fate, identifying 2 Neurog2-regulated transcriptional programs involved in the latter. First, we show that the Neurog2-transcriptional target Tbr2 is a direct transcriptional repressor of the ventral gene Ebf1. Secondly, we demonstrate that Neurog2 indirectly turns off Etv1 expression, which in turn indirectly regulates the expression of the ventral proneural gene Ascl1. Neurog2 thus activates several genetic off-switches, each with distinct transcriptional targets, revealing an unappreciated level of specificity for how Neurog2 prevents inappropriate gene expression during neocortical development.

Photocurable and Temperature-Sensitive Bioadhesive Hydrogels for Sutureless Sealing of Full-Thickness Corneal Wounds.

Penetrating corneal wounds can cause severe vision impairment and require prompt intervention to restore globe integrity and minimize the risk of infection. Tissue adhesives have emerged as a promising alternative to suturing for mitigating postoperative complications. However, conventional water-soluble adhesives suffer formidable challenges in sealing penetrating corneal wounds due to dilution or loss in a moist environment. Inspired by the robust adhesion of mussels in aquatic conditions, an injectable photocurable bioadhesive hydrogel (referred to as F20HD5) composed of polyether F127 diacrylate and dopamine-modified hyaluronic acid methacrylate is developed for sutureless closure of corneal full-thickness wounds. F20HD5 exhibits high transparency, wound-sealing ability, proper viscosity, biodegradability, and excellent biocompatibility. It allows in situ cross-linking via visible light, thereby providing sufficient mechanical strength and adhesiveness. In vivo, the adhesive hydrogel effectively closed penetrating linear corneal incisions and corneal injuries with minimal tissue loss in rabbits. During the 56-day follow-up, the hydrogel facilitates the repair of the injured corneas, resulting in more symmetrical curvatures and less scarring in distinction to the untreated control. Thus, bioinspired hydrogel holds promise as an effective adhesive for sealing full-thickness corneal wounds.

Cellular structural and functional imaging of donor and pathological corneas with label-free dual-mode full-field optical coherence tomography.

In this study, a dual-mode full-field optical coherence tomography (FFOCT) was customized for label-free static and dynamic imaging of corneal tissues, including donor grafts and pathological specimens. Static images effectively depict relatively stable structures such as stroma, scar, and nerve fibers, while dynamic images highlight cells with active intracellular metabolism, specifically for corneal epithelial cells. The dual-mode images complementarily demonstrate the 3D microstructural features of the cornea and limbus. Dual-modal imaging reveals morphological and functional changes in corneal epithelial cells without labeling, indicating cellular apoptosis, swelling, deformation, dynamic signal alterations, and distinctive features of inflammatory cells in keratoconus and corneal leukoplakia. These findings propose dual-mode FFOCT as a promising technique for cellular-level cornea and limbus imaging.

GSK3 temporally regulates neurogenin 2 proneural activity in the neocortex.

The neocortex is comprised of six neuronal layers that are generated in a defined temporal sequence. While extrinsic and intrinsic cues are known to regulate the sequential production of neocortical neurons, how these factors interact and function in a coordinated manner is poorly understood. The proneural gene Neurog2 is expressed in progenitors throughout corticogenesis, but is only required to specify early-born, deep-layer neuronal identities. Here, we examined how neuronal differentiation in general and Neurog2 function in particular are temporally controlled during murine neocortical development. We found that Neurog2 proneural activity declines in late corticogenesis, correlating with its phosphorylation by GSK3 kinase. Accordingly, GSK3 activity, which is negatively regulated by canonical Wnt signaling, increases over developmental time, while Wnt signaling correspondingly decreases. When ectopically activated, GSK3 inhibits Neurog2-mediated transcription in cultured cells and Neurog2 proneural activities in vivo. Conversely, a reduction in GSK3 activity promotes the precocious differentiation of later stage cortical progenitors without influencing laminar fate specification. Mechanistically, we show that GSK3 suppresses Neurog2 activity by influencing its choice of dimerization partner, promoting heterodimeric interactions with E47 (Tcfe2a), as opposed to Neurog2-Neurog2 homodimer formation, which occurs when GSK3 activity levels are low. At the functional level, Neurog2-E47 heterodimers have a reduced ability to transactivate neuronal differentiation genes compared with Neurog2-Neurog2 homodimers, both in vitro and in vivo. We thus conclude that the temporal regulation of Neurog2-E47 heterodimerization by GSK3 is a central component of the neuronal differentiation "clock" that coordinates the timing and tempo of neocortical neurogenesis in mouse.

Dual-crosslinked regenerative hydrogel for sutureless long-term repair of corneal defect.

Corneal transplantation is the most effective clinical treatment for corneal defects, but it requires precise size of donor corneas, surgical sutures, and overcoming other technical challenges. Postoperative patients may suffer graft rejection and complications caused by sutures. Ophthalmic glues that can long-term integrate with the corneal tissue and effectively repair the focal corneal damage are highly desirable. Herein, a hybrid hydrogel consisting of porcine decellularized corneal stroma matrix (pDCSM) and methacrylated hyaluronic acid (HAMA) was developed through a non-competitive dual-crosslinking process. It can be directly filled into corneal defects with various shapes. More importantly, through formation of interpenetrating network and stable amide bonds between the hydrogel and adjacent tissue, the hydrogel manifested excellent adhesion properties to achieve suture-free repair. Meanwhile, the hybrid hydrogel not only preserved bioactive components from pDCSM, but also exhibited cornea-matching transparency, low swelling ratio, slow degradation, and enhanced mechanical properties, which was capable of withstanding superhigh intraocular pressure. The combinatorial hydrogel greatly improved the poor cell adhesion performance of HAMA, supported the viability, proliferation of corneal cells, and preservation of keratocyte phenotype. In a rabbit corneal stromal defect model, the experimental eyes treated with the hybrid hydrogel remained transparent and adhered intimately to the stroma bed with long-term retention, accelerated corneal re-epithelialization and wound healing. Giving the advantages of high bioactivity, low-cost, and good practicality, the dual-crosslinked hybrid hydrogel served effectively for long-term suture-free treatment and tissue regeneration after corneal defect.

Flicker downregulates the content of crystallin proteins in form-deprived C57BL/6 mouse retina.

Image degradation by loss of higher spatial frequencies causes form-deprivation myopia (FDM) in humans and animals, and cyclical illumination (flicker) at certain frequencies may prevent FDM. The molecular mechanisms underlying FDM and its prevention by flicker are poorly known. To understand them better, we have identified proteins that differ in amount in form-deprived (FD) mouse retinas, under steady versus flickering light. Male C57BL/6 mice (age 27-29 days) were randomly divided into three groups: Experimental - monocularly form-deprived, and kept under either normal room light ("FD-Only") or 20 Hz flickering light ("FD-Flicker"), throughout the 12-hour light phase; and Control ("Open-Control") - kept under normal illumination, without form deprivation. After two weeks of treatment, retinal proteins were extracted and separated by two-dimensional gel electrophoresis (2D-GE); proteins that differ in content in FD-only versus FD-flicker retinas were identified by mass spectroscopy ("MS"), and their identities were verified by western blotting. The contents of three identified proteins differed statistically in FD-only compared to FD-flicker retinas. These proteins were identified by MS as α-A-crystallin, crystallin ß A2 and crystallin ß A1. Quantitative western blotting showed that the relative amount of α-A-crystallin in FD-only retinas was significantly higher than that in FD-Flicker and control retinas. In conclusion, form deprivation induced significant increases in the amounts of crystallins in mouse retinas. These increases were significantly reduced by exposure to 20 Hz flicker. Since form deprivation is known to induce myopia development, and flicker to prevent it, our data suggest that FD- and flicker-responsive changes in the content of crystallin proteins may be involved causally or protectively in myopia development.