A Gellan Gum, Polyethylene Glycol, Hydroxyapatite Composite Scaffold with the Addition of Ginseng Derived Compound K with Possible Applications in Bone Regeneration.

Engineered bone scaffolds should mimic the natural material to promote cell adhesion and regeneration. For this reason, natural biopolymers are becoming a gold standard in scaffold production. In this study, we proposed a hybrid scaffold produced using gellan gum, hydroxyapatite, and Poly (ethylene glycol) within the addition of the ginseng compound K (CK) as a candidate for bone regeneration. The fabricated scaffold was physiochemically characterized. The morphology studied by scanning electron microscopy (SEM) and image analysis revealed a pore distribution suitable for cells growth. The addition of CK further improved the biological activity of the hybrid scaffold as demonstrated by the MTT assay. The addition of CK influenced the scaffold morphology, decreasing the mean pore diameter. These findings can potentially help the development of a new generation of hybrid scaffolds to best mimic the natural tissue.

Magnetic Hydroxyapatite Composite Nanoparticles for Augmented Differentiation of MC3T3-E1 Cells for Bone Tissue Engineering.

Progressive aging harms bone tissue structure and function and, thus, requires effective therapies focusing on permanent tissue regeneration rather than partial cure, beginning with regenerative medicine. Due to advances in tissue engineering, stimulating osteogenesis with biomimetic nanoparticles to create a regenerative niche has gained attention for its efficacy and cost-effectiveness. In particular, hydroxyapatite (HAP, Ca10(PO4)6(OH)2) has gained significant interest in orthopedic applications as a major inorganic mineral of native bone. Recently, magnetic nanoparticles (MNPs) have also been noted for their multifunctional potential for hyperthermia, MRI contrast agents, drug delivery, and mechanosensitive receptor manipulation to induce cell differentiation, etc. Thus, the present study synthesizes HAP-decorated MNPs (MHAP NPs) via the wet chemical co-precipitation method. Synthesized MHAP NPs were evaluated against the preosteoblast MC3T3-E1 cells towards concentration-dependent cytotoxicity, proliferation, morphology staining, ROS generation, and osteogenic differentiation. The result evidenced that MHAP NPs concentration up to 10 µg/mL was non-toxic even with the time-dependent proliferation studies. As nanoparticle concentration increased, FACS apoptosis assay and ROS data showed a significant rise in apoptosis and ROS generation. The MC3T3-E1 cells cocultured with 5 µg/mL MHAP NPs showed significant osteogenic differentiation potential. Thus, MHAP NPs synthesized with simple wet chemistry could be employed in bone regenerative therapy.

Microplastic contamination in commercial fish species in southern coastal region of India.

Due to its potential impact on food safety and human health, commercial species that have been contaminated with microplastics (MPs) are drawing more attention on a global scale. This study investigated the possibility of MPs contamination in different marine fish species with substantial commercial value that was captured off the south coast of India, from Adyar and Ennore regions. Over the course of six months, from October 2019 to March 2020, 220 fish were examined. It was discovered that the gills and guts had accumulated more numbers of MPs (1115 MPs) of which 68% were fibres and fragments. The commercial fish samples contained an average of 3.2-7.6 MPs per fish. Greater MPs pollution is seen in the Ennore regions. The prevalence of MPs was observed in carnivorous and planktivorous fish collected from both the sites. Fish guts contained the most MPs, according to the data. Pelagic fish accounted for the least amount of MPs, followed by mid- and demersal fish. Four different types of polymers were also identified in the present study: polyethylene, polypropylene, polystyrene, and polyamide. These results clearly showed the degree of microplastic contamination in fish tissues from the south Indian coastal regions of Adyar and Ennore. These results we hope will create a baseline data for MPs contamination in commercial fish species. The presence of MPs in the fish could have detrimental effects both on the environment and human health and thus comprehensive steps are required to prevent plastic pollution of the environment in south India's coastal region.

Bioengineered corneal tissue for minimally invasive vision restoration in advanced keratoconus in two clinical cohorts.

Visual impairment from corneal stromal disease affects millions worldwide. We describe a cell-free engineered corneal tissue, bioengineered porcine construct, double crosslinked (BPCDX) and a minimally invasive surgical method for its implantation. In a pilot feasibility study in India and Iran (clinicaltrials.gov no. NCT04653922 ), we implanted BPCDX in 20 advanced keratoconus subjects to reshape the native corneal stroma without removing existing tissue or using sutures. During 24 months of follow-up, no adverse event was observed. We document improvements in corneal thickness (mean increase of 209 ± 18 µm in India, 285 ± 99 µm in Iran), maximum keratometry (mean decrease of 13.9 ± 7.9 D in India and 11.2 ± 8.9 D in Iran) and visual acuity (to a mean contact-lens-corrected acuity of 20/26 in India and spectacle-corrected acuity of 20/58 in Iran). Fourteen of 14 initially blind subjects had a final mean best-corrected vision (spectacle or contact lens) of 20/36 and restored tolerance to contact lens wear. This work demonstrates restoration of vision using an approach that is potentially equally effective, safer, simpler and more broadly available than donor cornea transplantation.

Honey-Propolis-Engineered Collagen Peptides as Promising Wound-Healing Matrix in Mouse Model.

In this study, collagen hydrolysates (CHDs) were fabricated with honey-propolis wax (HPW), structurally modified as a sponge matrix, and experimentalized on wound healing in a mouse model. The scaffold was characterized by means of in vitro enzymatic degradation; in vitro HPW release; and in vivo wound-healing mouse model, wound-healing-specific RNA, transcripts, and protein markers. The functional activity of the HPW extracted from raw propolis was determined using total flavonoids, antioxidant scavenging assays, and anti-hemolytic principles. The results indicated that HPW had a high flavonoid content (20 µg/mL of wax) and antioxidant activities. The effective concentration (EC50) of HPW was estimated (28 mg/mL) and was then used in the subsequent in vivo experiments. Additionally, the dopped mixture of CHDs and HPW substantially enhanced the wound-healing process and regulated wound biochemical markers such as hexoseamine and melondialdehyde. CHDs- HPW upregulated the expression of growth factors including vascular endothelial growth factor (VEGF) (2.3-fold), fibroblast growth factor (FGF) and epidermal growth factor (EGF) (1.7-fold), and transforming growth factor-beta (TGF-ß) (3.1-fold), indicating their potential capacity to perform wound re-epithelialization and the loading of ground tissue. Pro-inflammatory markers IL-1 ß (51 pg/mL) and TNF-α (220 pg/mL) were significantly reduced in the CHD-HPW-treated wound. These interesting results were further confirmed using mRNA and protein growth factors from the wound, which enhanced the load of collagen-I in the wound site. In conclusion, CHDs-HPW exhibited a significant reduction in inflammation and inflammatory markers and helped to obtain a faster wound-healing process in a mouse model. The newly engineered biosponge could be developed as a promising therapeutic approach for the regeneration and repair of damaged human skin in the future.

Isolation and screening of potassium solubilizing bacteria from saxicolous habitat and their impact on tomato growth in different soil types.

Bacteria that solubilize nutrients in the soil are commonly used as bio-inoculants for promoting the growth of different crop species. However, the influence of potassium (K) solubilizing bacteria (KSB) originating from saxicolous habitat (rock-dwelling) on plant growth has not been frequently examined. In this study, we isolated KSB from saxicolous habitats and estimated their ability to produce plant growth hormone, organic acids, and siderophore that may facilitate plant growth. Fifteen culturable saxicolous bacterial isolates with varied K solubilizing ability were isolated from two sites. Of these, four potential K solubilizers were selected and identified by 16S rRNA gene sequencing. The four bacterial isolates resembled Bacillus subtilis, Bacillus cereus, Bacillus licheniformis, and Burkholderia cenocepacia and produced different organic acids, indole acetic acid, and siderophore under in vitro conditions. Potassium solubilization differed among the bacterial isolates and was significantly influenced by K sources. Inoculation of KSB improved the tomato plant growth parameters like plant height, leaf area, total root length, root/shoot ratio, and tissue K content in sterilized and unsterilized Alfisol, and Vertisol soils under greenhouse conditions. We also observed higher residual K content in the KSB inoculated post-harvest soils. Among the four KSB isolates screened, B. licheniformis and B. cenocepacia presents an excellent prospect as bio-inoculants for improving tomato growth in different soil types. Besides these, the enriched K content in the post-harvest soils may help the growth of subsequent crops in sustainable agriculture.

A porous collagen-based hydrogel and implantation method for corneal stromal regeneration and sustained local drug delivery.

Biomaterials designed to replace the diseased cornea could be used to treat corneal blindness where human donor tissue is in short supply, but challenges are the integration of biomaterials with host tissue and cells, avoiding a rapid material degradation and maintaining corneal transparency. Additionally, implantation surgery often triggers an aggressive wound healing response that can lead to corneal thinning and opacity. Here, we report a collagen-based hydrogel with transparency and mechanical properties suitable for replacing a substantial portion of a damaged or diseased corneal stroma. The porous hydrogel permitted migration and population by host cells while maintaining transparency and thickness six months after surgical implantation in an in vivo model of human corneal surgery. With a novel hybrid surgical implantation technique inspired by LASIK refractive surgery, rapid wound healing occurred around implants to maintain biomaterial integrity, transparency and function. Host stromal cell repopulation and regeneration of host epithelium and nerves were observed, as necessary steps towards corneal regeneration. Finally, as a proof-of-principle, the hydrogel loaded with a neuroregenerative drug achieved sustained slow-release drug delivery in vitro. The proposed hydrogel and novel implantation technique together represent a therapeutic approach with translational potential for replacing and regenerating diseased corneal stromal tissue.

Bone Regeneration Using Duck's Feet-Derived Collagen Scaffold as an Alternative Collagen Source.

Collagen is an important component that makes 25-35% of our body proteins. Over the past decades, tissue engineers have been designing collagen-based biocompatible materials and studying their applications in different fields. Collagen obtained from cattle and pigs has been mainly used until now, but collagen derived from fish and other livestock has attracted more attention since the outbreak of mad cow disease, and they are also used as a raw material for cosmetics and foods. Due to the zoonotic infection using collagen derived from pigs and cattle, their application in developing biomaterials is limited; hence, the development of new animal-derived collagen is required. In addition, there is a religion (Islam, Hinduism, and Judaism) limited to export raw materials and products derived from cattle and pig. Hence, high-value collagen that is universally accessible in the world market is required. Therefore, in this review, we have dealt with the use of duck's feet-derived collagen (DC) as an emerging alternative to solve this problem and also presenting few original investigated bone regeneration results performed using DC.

Enhancing Osteochondral Tissue Regeneration of Gellan Gum by Incorporating Gallus gallus var Domesticus-Derived Demineralized Bone Particle.

Treatment for the osteochondral defects (ODs) is more challenging nowadays that needs to be addressed by developing alternative bone tissue engineering materials. Gellan gum (GG) is a widely used natural polysaccharide in the field of tissue engineering (TE) and regenerative medicine due to its versatile properties. There are many reports about the successful application of GG in cartilage tissue engineering and guiding bone formation. Functional coatings and porous composite materials have been introduced in next-generation materials for treating OD, whereas osteoconductive materials, such as demineralized bone particle (DBP) or bone derivatives, are used. However, modification of porosity, biocompatibility, cell proliferation, and mechanical properties is needed. DBP can activate human mesenchymal stem cells to differentiate into osteoblast cells. In this chapter, the potential application of GG with DBP in different combinations was reviewed, and the best suitable combinations were selected and further studied in small animal models for the soft and hard tissue engineering applications; also its application in the osteochondral integration fields were briefly discussed.

Exosome mediated transfer of miRNA-140 promotes enhanced chondrogenic differentiation of bone marrow stem cells for enhanced cartilage repair and regeneration.

Exosomes (EXs) are nanocarrier vesicles with 20-50 nm dimensions. They are involved in cell proliferation and differentiation and in protecting the integrity of materials. They can be isolated from plasma and immunoreactive components. Recent studies demonstrated their potential role in cartilage regeneration. To enhance their regenerative effect, molecules like microRNA (miR-140) can be loaded in EX that acts as RNA delivery systems. In this study, we combined EX with miR-140 to enhance cell differentiation by inducing membrane fusion and consequent miRNA released into the cytoplasm. The carrier RNA complex was successfully synthesized through freeze and thaw method leading to the formation of EX-containing miR-140. The EX morphology was assessed through transmission electron microscopy and their miR-140 uptake efficiency through real-time polymerase chain reaction (RT-PCR). The effects on bone marrow stem cells (BMSCs) were evaluated by in vitro cell culture. Cell adhesion and morphology were studied using a bio-scanning electron microscope and confocal laser scanning microscope. Differentiation BMSCs into chondrocytes was analyzed by RT-PCR and histology. Our results confirm the bioactive role of EX loaded with miR-140 in the differentiation of BMSCs into chondrocytes. EXs were biocompatible involving in the cartilage healing process through chromogenic differentiation of BMCS exploiting the tissue engineering route.

Osteochondral and bone tissue engineering scaffold prepared from Gallus var domesticus derived demineralized bone powder combined with gellan gum for medical application.

Osteochondral (OC) lesions can occur in the knee and ankle. Such lesions induce a fracture in the cartilage protecting the bone joints. Cartilage tissue shows limited self-regeneration ability, hence the tissue is avascular and lack of vascular innervation, while the bone is a unique organ with the capacity to self-repair of small defects. In this present study, we have prepared a scaffold using demineralized bone powder (DBP) extracted from Gallus gallus var domesticus (GD), and Gellan gum (GG) for OC tissue regeneration. They were characterized for their chemical, physical, mechanical and biological properties using different available techniques, in vitro bioactivity was performed in simulated body fluid for 14 days confirming the formation of bone-like apatite. The in vitro biocompatibility was analyzed using chondrocyte cells and osteogenic and chondrogenic marker gene expression using RT-PCR, in vivo experiments performed by implanting scaffold in rabbit and characterized by histology and immunofluorescent stainings. The obtained results indicated that the prepared pores scaffold was biocompatible, and promote OC regeneration and integration of newly formed tissues with the host tissues in a rabbit. The prepared 1% DBP/GG scaffold can be used as a potential and promising alternate material for OC regeneration.

A BMSCs-laden quercetin/duck's feet collagen/hydroxyapatite sponge for enhanced bone regeneration.

Treating critical-sized bone defects is an important issue in the field of tissue engineering and bone regeneration. From the various biomaterials for bone regeneration, collagen is an important and widely used biomaterial in biomedical applications, hence, it has numerous attractive properties including biocompatibility, hyper elastic behavior, prominent mechanical properties, support cell adhesion, proliferation, and biodegradability. In the present study, collagen was extracted from duck's feet (DC) as a new collagen source and combined with quercetin (Qtn), a type of flavonoids found in apple and onions and has been reported to affect the bone metabolism, for increasing osteogenic differentiation. Further, improving osteoconductive properties of the scaffold hydroxyapatite (HAp) a biodegradable material was used. We prepared 0, 25, 50, and 100 µM Qtn/DC/HAp sponges using Qtn, DC, and HAp. Their physiochemical characteristics were evaluated using scanning electron microscopy, compressive strength, porosity, and Fourier transform infrared spectroscopy. To assess the effect of Qtn on osteogenic differentiation, we cultured bone marrow mesenchymal stem cells on the sponges and evaluated by alkaline phosphatase, 3-4-2, 5-diphenyl tetrazolium bromide assay, and real-time polymerase chain reaction. Additionally, they were studied implanting in rat, analyzed through Micro-CT and histological staining. From our in vitro and in vivo results, we found that Qtn has an effect on bone regeneration. Among the different experimental groups, 25 µM Qtn/DC/HAp sponge was found to be highly increased in cell proliferation and osteogenic differentiation compared with other groups. Therefore, 25 µM Qtn/DC/HAp sponge can be used as an alternative biomaterial for bone regeneration in critical situations.

Ginseng compound K incorporated porous Chitosan/biphasic calcium phosphate composite microsphere for bone regeneration.

There is a substantial for the bone graft materials in the clinical field. Porous, stable and biodegradable bone microsphere scaffold using biopolymer chitosan was studied, and biphasic calcium phosphate was added to improve mechanical and osteoconductivity properties later ginseng compound K was added for improving its medicinal properties. They were characterized using FTIR and XRD that showed the apatite crystal in the composite microsphere scaffolds were structurally similar to that of biogenic apatite crystals. Scanning electron microscopy images confirmed the presence of hydroxyapatite on the surface of the composite microspheres. In vitro results infers that the composite microspheres are biocompatible with NIH 3T3 and MG63 cells and capable of supporting growth and spreading of MG-63 cells. Further, Osteogenic markers expression was found to be higher in rat bone marrow stem cells seeded on microsphere scaffolds compared to control. The prepared biocomposite porous microsphere scaffold developed in this study can be used as an alternative for the bone regeneration or bone tissue engineering.

Revascularization after angiogenesis inhibition favors new sprouting over abandoned vessel reuse.

Inhibiting pathologic angiogenesis can halt disease progression, but such inhibition may offer only a temporary benefit, followed by tissue revascularization after treatment stoppage. This revascularization, however, occurs by largely unknown phenotypic changes in pathologic vessels. To investigate the dynamics of vessel reconfiguration during revascularization, we developed a model of reversible murine corneal angiogenesis permitting longitudinal examination of the same vasculature. Following 30 days of angiogenesis inhibition, two types of vascular structure were evident: partially regressed persistent vessels that were degenerate and barely functional, and fully regressed, non-functional empty basement membrane sleeves (ebms). While persistent vessels maintained a limited flow and retained collagen IV+ basement membrane, CD31+ endothelial cells (EC), and α-SMA+ pericytes, ebms were acellular and expressed only collagen IV. Upon terminating angiogenesis inhibition, transmission electron microscopy and live imaging revealed that revascularization ensued by a rapid reversal of EC degeneracy in persistent vessels, facilitating their phenotypic normalization, vasodilation, increased flow, and subsequent new angiogenic sprouting. Conversely, ebms were irreversibly sealed from the circulation by excess collagen IV deposition that inhibited EC migration and prevented their reuse. Fully and partially regressed vessels therefore have opposing roles during revascularization, where fully regressed vessels inhibit new sprouting while partially regressed persistent vessels rapidly reactivate and serve as the source of continued pathologic angiogenesis.

Repeat Corneal Neovascularization is Characterized by More Aggressive Inflammation and Vessel Invasion Than in the Initial Phase.

Purpose: Treatment of corneal neovascularization can lead to vessel regression and recovery of corneal transparency. Here, we examined the response of the cornea to a repeated stimulus after initial vessel regression comparing the second wave of neovascularization with the first. Methods: Corneal neovascularization was induced by surgical suture placement in the rat cornea for 7 days, followed by suture removal and a 30-day regression period. Corneas were then re-sutured and examined for an additional 4 days. Longitudinal slit-lamp imaging, in vivo confocal microscopy, and microarray analysis of global gene expression was conducted to assess the inflammatory and neovascularization response. Inhibitory effect of topical dexamethasone for repeat neovascularization was assessed. Results: After initial robust neovascularization, 30 days of regression resulted in the recovery of corneal transparency; however, a population of barely functional persistent vessels remained at the microscopic level. Upon re-stimulation, inflammatory cell invasion, persistent vessel dilation, vascular invasion, and gene expression of Vegfa, Il1ß, Il6, Ccl2, Ccl3, and Cxcl2 all doubled relative to initial neovascularization. Repeat neovascularization occurred twice as rapidly as initially, with activation of nitric oxide and reactive oxygen species, matrix metalloproteinase, and leukocyte extravasation signaling pathways, and suppression of anti-inflammatory LXR/RXR signaling. While inhibiting initial neovascularization, a similar treatment course of dexamethasone did not suppress repeat neovascularization. Conclusions: Persistent vessels remaining after the initial resolution of neovascularization can rapidly reactivate to facilitate more aggressive inflammation and repeat neovascularization, highlighting the importance of achieving and confirming complete vessel regression after an initial episode of corneal neovascularization.

Injectable taurine-loaded alginate hydrogels for retinal pigment epithelium (RPE) regeneration.

The purpose of this study is to produce injectable taurine (Tr)-loaded alginate (Agn) hydrogel for age-related macular degeneration (AMD) treatment by inducing the regeneration of RPE (retinal pigment epithelium) cells. Porosity and swelling ratio were measured to evaluate the mechanical properties of the hydrogels, and Fourier transform infrared spectroscopy (FTIR) was used to evaluate the physical and chemical properties. RPE cells extracted from the pigmented epithelium of rabbits were encapsulated in the Tr/Agn hydrogels. Cells proliferation and migration were improved in Tr/Agn hydrogels with an enhanced expression of RPE-specific genes including RPE65, CRALBP, NPR-A, MITF and collagen type I and II. In vivo tests demonstrated the excellent biocompatibility and biodegradability without inflammatory response by the host when implanted with the hydrogel. Moreover, when the Tr/Agn hydrogels were injected into the sub-retinal space, high adhesion of RPE cells and retinal regeneration were confirmed. These results demonstrated a potential role of injectable Tr/Agn hydrogels as potential therapeutic tools for the treatment of retinal diseases, including AMD.

Effect of different concentration of demineralized bone powder with gellan gum porous scaffold for the application of bone tissue regeneration.

The prevalence of bone-related diseases has increased, the population growth as a result of the aging phenomenon requires more effective treatments for regeneration of bone defect. Although an autogenous bone graft was used in traditional operation method, they are very inefficient in current bone defect surgery and very difficult to gather the required amount of bone for operation. It is becoming a gradually growing disease, hence there is a need for developing a new method for preparing biomimetic scaffolds. DBP (demineralized bone powder), a potent bone regeneration material, has a trace amount of ions and bone mineral component. Especially, GD (Gallus gallus var domesticus) DBP has a unique property, which has melanin, for strengthening bones, increasing ALP activity and bone mineralization, compared to other available biomaterials. For that reason, GD DBP was combined with GG (gellan gum). The material was characterized in vitro and in vivo rat model. The first priority in this work was given to assessing the attachment and proliferation rates of BMSCs following the in vivo experiment in rats. The results of 1% sample showed better osteogenic effects that can be used in clinical application after studying in larger animals for better bone regeneration and tissue engineering.

Engineering retinal pigment epithelial cells regeneration for transplantation in regenerative medicine using PEG/Gellan gum hydrogels.

Retinal pigment epithelium (RPE) plays an important role in maintaining normal function and visual function of the retina, and the degeneration of RPE causes various retinal degenerative diseases. Currently, there is a lack of effective treatment for this, and it is being studied to produce a suitable scaffold for cell transplantation. In this experiment, Polyethylene glycol (PEG)/Gellan Gum (GG) hydrogel was prepared by adding harmless PEG and gellan gum, which is a biocompatible, degradable and widely used in modern tissue engineering. PEG/GG hydrogel was prepared with 0, 1, 3, 5 wt% PEG/GG according to the concentration of PEG, and ARPE-19 cells were used to confirm the cell attachment environment. As a result, it showed superior biocompatibility (>90%), cell adhesion and improved cell growth compared to gellan gum hydrogel. In addition, RT-PCR was used to confirm RPE-specific gene expression, and the result showed that it was positively influenced. As a result, it was observed that PEG/GG hydrogel promotes retinal regeneration compared to pure gellan gum. 3 wt% PEG/GG could be used as an alternative for retinal regeneration.

Morphological Modification of Carbon Nanoparticles after Interacting with Methotrexate as a Potential Anticancer Agent.

PURPOSE: Production of highly penetrable and targetable drug delivery particles is mainly focused by current therapy and such focus is achieved in our present study. The carbon nanoparticle (CNP) prepared from purely natural source was modified from spherical shape to cylindrical floral like structure after treatment with the anticancer drug methotrexate (CM). METHODS: The physiochemical properties of the CNP and CM was characterized using FT-IR/Raman Spectrometer, XRD, SEM, AFM, particle size analyzer and its biological evaluation using haemolysis and MTT assay. RESULTS: The shift in FT-IR peaks at 1592, 1120 cm-1 and peaks of raman spectra observed at 1303, 1300 cm-1 represents ordered carbon nanotubes. The morphological change from spherical to cylindrical floral like structure was observed using SEM and AFM and its particle size distribution analysis shows an average diameter of 269 nm for CM. XRD peak at 2θ = 23.86° (002) indicates the presence of large amount of amorphous material that corresponds to multi-walled carbon nanotubes. Haemocompatibility studies proved the safety level usage as 100 µg/ml and MTT assay shows viability rate of 85-98% with mouse embryonic fibroblast (NIH/3 T3) and 30-45% with pancreatic carcinoma (MIA PaCa-2) and gastric cancer cell lines (SNU- 484) respectively.These results are also supported by phase contrast microscope images observed after staining with calcein AM and EthD-1. CONCLUSIONS: The morphologically modified CNPs has shown good anticancer, biocompatibility and haemocompatibility property which is an important criterion to be satisfied by a biomedical product.

Selective IKK2 inhibitor IMD0354 disrupts NF-κB signaling to suppress corneal inflammation and angiogenesis.

Corneal neovascularization is a sight-threatening condition caused by angiogenesis in the normally avascular cornea. Neovascularization of the cornea is often associated with an inflammatory response, thus targeting VEGF-A alone yields only a limited efficacy. The NF-κB signaling pathway plays important roles in inflammation and angiogenesis. Here, we study consequences of the inhibition of NF-κB activation through selective blockade of the IKK complex IκB kinase ß (IKK2) using the compound IMD0354, focusing on the effects of inflammation and pathological angiogenesis in the cornea. In vitro, IMD0354 treatment diminished HUVEC migration and tube formation without an increase in cell death and arrested rat aortic ring sprouting. In HUVEC, the IMD0354 treatment caused a dose-dependent reduction in VEGF-A expression, suppressed TNFα-stimulated expression of chemokines CCL2 and CXCL5, and diminished actin filament fibers and cell filopodia formation. In developing zebrafish embryos, IMD0354 treatment reduced expression of Vegf-a and disrupted retinal angiogenesis. In inflammation-induced angiogenesis in the rat cornea, systemic selective IKK2 inhibition decreased inflammatory cell invasion, suppressed CCL2, CXCL5, Cxcr2, and TNF-α expression and exhibited anti-angiogenic effects such as reduced limbal vessel dilation, reduced VEGF-A expression and reduced angiogenic sprouting, without noticeable toxic effect. In summary, targeting NF-κB by selective IKK2 inhibition dampened the inflammatory and angiogenic responses in vivo by modulating the endothelial cell expression profile and motility, thus indicating an important role of NF-κB signaling in the development of pathologic corneal neovascularization.