Macrophages Modulate Optic Nerve Crush Injury Scar Formation and Retinal Ganglion Cell Function.

Purpose: Optic nerve (ON) injuries can result in vision loss via structural damage and cellular injury responses. Understanding the immune response, particularly the role of macrophages, in the cellular response to ON injury is crucial for developing therapeutic approaches which affect ON injury repair. The present study investigates the role of macrophages in ON injury response, fibrotic scar formation, and retinal ganglion cell (RGC) function. Methods: The study utilizes macrophage Fas-induced apoptosis (MaFIA) mice to selectively deplete hematogenous macrophages and explores the impact macrophages have on ON injury responses. Histological and immunofluorescence analyses were used to evaluate macrophage expression levels and fibrotic scar formation. Pattern electroretinogram (PERG) recordings were used to assess RGC function as result of ON injury. Results: Successful macrophage depletion was induced in MaFIA mice, which led to reduced fibrotic scar formation in the ON post-injury. Despite an increase in activated macrophages in the retina, RGC function was preserved, as demonstrated by normal PERG waveforms for up to 2 months post-injury. The study suggests a neuroprotective role for macrophage depletion in ON damage repair and highlights the complex immune response to ON injury. Conclusions: To our knowledge, this study is the first to use MaFIA mice to demonstrate that targeted depletion of hematogenous macrophages leads to a significant reduction in scar size and the preservation of RGC functionality after ON injury. These findings highlight the key role of hematogenous macrophages in the response to ON injury and opens new avenues for therapeutic interventions in ON injuries. Future research should focus on investigating the distinct roles of macrophage subtypes in ON injury and potential macrophage-associated molecular targets to improve ON regeneration and repair.

Disclosing phototransformation mechanisms of decabromodiphenyl ether (BDE-209) in different media by simulated sunlight: Implication by compound-specific stable isotope analysis.

As one of the typical brominated flame retardants, decabromodiphenyl ether (BDE-209) has been widely detected in environment. However, scarce information was available on BDE-209 phototransformation mechanisms in various media. In this study, compound-specific stable isotope analysis was first applied to investigate BDE-209 phototransformation in n-hexane, MeOH:H2O (v:v, 8:2), and simulated seawater by simulated sunlight. BDE-209 transformation followed pseudo-first-order kinetic, with degradation rate in the following of n-hexane (2.66 × 10-3 min-1) > simulated seawater (1.83 × 10-3 min-1) > MeOH:H2O (1.41 × 10-3 min-1). Pronounced carbon isotope fractionation was first observed for BDE-209 phototransformation, with carbon isotope enrichment factors (εC) of -1.01 ± 0.14‰, -1.77 ± 0.26‰, -2.94 ± 0.38‰ in n-hexane, MeOH:H2O and simulated seawater, respectively. Combination analysis of products and stable carbon isotope, debromination with cleavage of C-Br bonds as rate-limiting step was the main mechanism for BDE-209 phototransformation in n-hexane, debromination and hydroxylation with cleavage of C-Br bonds as rate-limiting steps in MeOH:H2O, and debromination, hydroxylation and chlorination in simulated seawater. This present study confirmed that stable carbon isotope analysis was a robust method to discovery the underlying phototransformation mechanisms of BDE-209 in various solutions.

Recombinant Human Clusterin Seals Damage to the Ocular Surface Barrier in a Mouse Model of Ophthalmic Preservative-Induced Epitheliopathy.

There is a significant unmet need for therapeutics to treat ocular surface barrier damage, also called epitheliopathy, due to dry eye and related diseases. We recently reported that the natural tear glycoprotein CLU (clusterin), a molecular chaperone and matrix metalloproteinase inhibitor, seals and heals epitheliopathy in mice subjected to desiccating stress in a model of aqueous-deficient/evaporative dry eye. Here we investigated CLU sealing using a second model with features of ophthalmic preservative-induced dry eye. The ocular surface was stressed by topical application of the ophthalmic preservative benzalkonium chloride (BAC). Then eyes were treated with CLU and sealing was evaluated immediately by quantification of clinical dye uptake. A commercial recombinant form of human CLU (rhCLU), as well as an rhCLU form produced in our laboratory, designed to be compatible with U.S. Food and Drug Administration guidelines on current Good Manufacturing Practices (cGMP), were as effective as natural plasma-derived human CLU (pCLU) in sealing the damaged ocular surface barrier. In contrast, two other proteins found in tears: TIMP1 and LCN1 (tear lipocalin), exhibited no sealing activity. The efficacy and selectivity of rhCLU for sealing of the damaged ocular surface epithelial barrier suggests that it could be of therapeutic value in treating BAC-induced epitheliopathy and related diseases.

DNA-templated copper nanoclusters as a fluorescent probe for fluoride by using aluminum ions as a bridge.

A selective fluorescent on-off-on probe has have designed for the detection of fluoride (F-) ions based on DNA-templated copper nanocluster (CuNCs) and by using aluminum(III) ions as a bridge. A 40-mer polythymine acts as a template for the reduction of Cu(II) to Cu(0) by ascorbic acid. This result is the formation of red fluorescent CuNCs, with excitation/emission peaks at 340/640 nm. After addition of Al3+ ions, the fluorescence of CuNCs is quenched because the interaction of Al3+ and DNA disturbs the formation of DNA-templated CuNCs. Fluorescence is restored on addition of fluoride to the system. This is due to the desorption of Al3+ from the DNA and the formation of the Al(OH)3F- complex. This system displays a fast fluorometric response to fluoride, with high selectivity over other anions. Fluorescence increases linearly in the 2 to 150 µM F- concentration range, and the detection limit is 1.0 µM. This probe has been successfully used for the detection of F- ions in four brands of toothpaste. The method is rapid, cost-effective, selective, and does not require toxic solvents and reagents. Graphical abstract Schematic presentation of a method for fluorometric determination of fluoride by using DNA-templated copper nanoclusters (CuNCs) and using aluminum(III) as a bridge. The red fluorescence of the CuNCs is quenched in the presence of Al(III) ions but restored after addition of fluoride.

RasGRF2 promotes migration and invasion of colorectal cancer cells by modulating expression of MMP9 through Src/Akt/NF-κB pathway.

Ras-specific guanine nucleotide-releasing factor 2 (RasGRF2) is a member of the guanine nucleotide exchange factors family which is expressed in a variety of tissues and cancer. However, the role of RasGRF2 in cancer is less reported, especially in colorectal cancer(CRC). Hence, the present study aimed to investigated the function of RasGRF2 and ways in which it affects tumor progression in CRC samples and cell lines. We first measured RasGRF2 mRNA level in 26 paired tumor and nontumor colon tissues after colon cancer surgical resection, and determined RasGRF2 protein level in 97 paired paraffin-embedded colon cancer tissues, and found that levels of RasGRF2 mRNA and protein were increased in colorectal tumor tissues, compared with adjacent non-tumor tissues. We then examined the effects of RasGRF2 knockdown on proliferation, migration and invasion were analyzed in CRC cells (SW480, HCT116 and LS174T). HCT116 cells with RasGRF2 knockdown were injected into the tail vein in nude mice to yield metastatic model, and tumor metastasis was measured as well. We found that knockdown of RasGRF2 in CRC cells reduced their migration and invasion in vitro and metastasis in mice. Furthermore, we explored the underlying molecular mechanism for RasGRF2-mediated CRC migration and invasion. The results showed that knockdown of RasGRF2 in CRC cells impairing the expression of MMP9 and inhibiting the activation of Src/Akt and NF-κB signaling. We conclude that RasGRF2 plays a role in controlling migration and invasion of CRC and modulates the expression of MMP9 through Src/PI 3-kinase and the NF-κB pathways.