Management of experimental trabeculectomy filtering blebs via crosslinking of the scleral flap inhibited vascularization.

PURPOSE: The aim of this study was to evaluate whether UVA-light-activated riboflavin-induced collagen crosslinking (UVA-CXL) can maintain the function of filtering blebs after trabeculectomy (TRAB) in rabbits. METHODS: Thirty-six healthy rabbits were randomized to one of the following groups with 12 rabbits in each group: Trabeculectomy group (TRAB group), trabeculectomy combined with CXL group (CXL group), and trabeculectomy combined with MMC group (MMC group). Six rabbits of each group were performed with intraocular pressure (IOP), optical coherence tomography (OCT), and OCT angiography (OCTA). Bleb structure was observed via hematoxylin & eosin (H&E) and Masson staining. Immunohistochemistry, proteomic study, western blot, and tensile test were performed between CXL group and the control. In vitro, cell viability was evaluated by CCK-8 and Calcein/PI staining. TRPV4 and VEGF-a expression levels were measured by Q-PCR. Ca2+ concentration was observed with Fluo-4 AM. RESULTS: The IOP and bleb median survival day were significantly modified in CXL (5.92 ± 0.32 mmHg and 15.5 days) than TRAB group (7.50 ± 0.43 mmHg and 9 days). The bleb area and height increased. CXL inhibited vascularization, and vascularization peaked at postoperative day (POD) 14 and then decreased gradually. In proteomic analyses, Z disc, actin filament binding, and sarcomere organization were significantly enriched. CXL inhibited scleral stress‒strain in tensile tests. Compared with TRAB group, TRPV4 expression was significantly increased, but VEGF-a and TGF-ß1 levels were reduced in the CXL group in western blot. Meanwhile, TRPV4 expression colocalized with CD31. In vitro, CXL inhibited HUVECs cell viability. After CXL, expression level of TRPV4 was increased and calcium influx was activated, but VEGF-a was decreased in HUVECs. CONCLUSIONS: This study demonstrates that intraoperative UV-RF CXL can significantly improve the success rate of TRAB via inhibiting filtering bleb vascularization. CXL increased sclera stiffness, in turn, induced TRPV4 activation, thus contributing to vascular endothelial cells suppression.

Number of and distance between response elements in Kaposi's sarcoma-associated herpesvirus ORF57 promoter influence its activation by replication and transcription activator and its repression by interferon regulatory factor 7.

Kaposi's sarcoma-associated herpesvirus ORF57 expression is highly responsive to replication and transcription activator (RTA) and interferon regulatory factor 7 (IRF-7). Three RTA response elements (RREs) have been identified in the ORF57 promoter. Here, we show evidence of another functional RRE located between nt 82003 and 82081, which can complement the loss of RTA activation resulting from RRE1 deletion. Repeats of a recombination signal-binding protein Jkappa (RBP-Jkappa) site enhanced RTA activation, which could not be suppressed by IRF-7. Alteration of the distance between the RBP-Jkappa site and RRE2 modulated responsiveness to RTA and IRF-7. These results will help to elucidate the precise regulation of viral gene expression.

In Situ Observation of Light Illumination-Induced Degradation in Organometal Mixed-Halide Perovskite Films.

Organometal mixed-halide perovskite materials hold great promise for next-generation solar cells, light-emitting diodes, lasers, and photodetectors. Except for the rapid progress in the efficiency of perovskite-based devices, the stability issue over prolonged light illumination has severely hindered their practical application. The deterioration mechanism of organometal halide perovskite materials under light illumination has seldom been conducted to date, which is indispensable to the understanding and optimization of photon-harvesting process inside perovskite-based optoelectronic devices. Here, explicit degradation pathways and comprehensive microscopic understandings of white-light-induced degradation have been put forward for two organometal mixed-halide perovskite materials (e.g., MAPbI3-xClx and MAPbBr3-xClx) under high vacuum conditions. In situ compositional analysis and real-time film characterizations reveal that the decomposition of both mixed-halide perovskites starts at the grain boundaries, leading to the formation of hydrocarbons and ammonia gas with the residuals of PbI2(Cl), Pb, or PbClxBr2-x in the films. The degradation has been correlated to the localized trap states that induce strong coupling between photoexcited carriers and the crystal lattice.