Photochemistry and Photobiology最新文献

Interest in antimicrobial photodynamic therapy for treating cutaneous leishmaniasis has been rising, showing promising outcomes and good patient tolerance. In this study, we aimed to develop a protocol for producing giant plasma membrane vesicles (GPMVs) from Leishmania amazonensis promastigote cell membranes, focusing on the role of membrane-embedded proteins during methylene blue (MB) photooxidation with red light. Membrane extraction was achieved via centrifugation with various sucrose gradients. We then generated GPMVs by electroformation, applying different frequencies and voltages over four cycles, and examined them using phase contrast optical microscopy. For MB photooxidation, GPMVs were dispersed in an aqueous solution with 50 μM MB and exposed to 665 nm light at 830 μW. A comparable approach was used for mimetic membranes (giant unilamellar vesicles, GUVs) made of Leishmania membrane lipids. MB photoactivation in GUVs caused a transient increase in membrane area and full permeability. Conversely, GPMVs showed an earlier onset of contrast loss but exhibited less overall contrast reduction and no expansion, indicating that membrane proteins in GPMVs modulate the response to oxidative stress. Real-time monitoring revealed morphological changes in L. amazonensis promastigote cells consistent with apoptosis following photodynamic inactivation.

Tandem reactions of singlet oxygen (¹O₂) with nonconjugated natural products, such as plastoquinones, have attracted attention. However, mechanistic clarity is needed for the ¹O₂ uptake sequence and regioselectivity. Our strategy was to study a tandem ¹O₂ reaction in a diprenylated phenol (geranyl phenol) bearing an inner and an outer prenyl group in the chain. Singlet oxygen first added to the inner prenyl group by H-bonding to the phenol OH, forming a gem-disubstituted and a tri-substituted dienyl dihydrobenzofuran. H₂O₂ was also released as a by-product. A second equivalent of ¹O₂ added by an "ene" reaction, but now to the outer rather than the inner site of the nonconjugated diene to reach four hydroperoxy-dihydrobenzofurans. There was no evidence for ¹O₂ "ene" reactions on the inner prenyl sites, but product decomposition included the formation of oxygen-centered radicals and even methane by a β-scission process. The results are an essential step in resolving mechanistic puzzles of reactive oxygen uptake in natural prenylated systems, which are important topics not only in physical-organic and synthetic chemistry but also in plant oxidation chemistry.

Skin photoaging is a skin condition caused by long-term exposure to ultraviolet radiation, especially UVA and UVB, which leads to wrinkles, pigmentation, skin sagging, and telangiectasia. Histopathologically, it is characterized by a significant reduction in dermal collagen and abnormal accumulation of elastic fibers. Preventing or ameliorating photoaging may provide a promising therapeutic approach for these changes. In recent years, multiple studies have reported the potential of mesenchymal stem cells (MSCs) in treating various skin diseases. Given that extracellular vesicles (EVs) can deliver diverse substances to receptor cells and produce therapeutic effects similar to parental cells, we aim to explore whether adipose-derived mesenchymal stem cell-derived extracellular vesicles (AMSC-EVs) can improve skin photoaging by delivering heat shock protein 27 (HSP27). The specific effects of AMSC-EVs on the photoaging model of human dermal fibroblasts (HDFs) or human immortalized keratinocytes (HaCaTs) induced by UVB irradiation were investigated through CCK-8 experiments, cell migration experiments, flow cytometry, immunofluorescence, and Western blot. Our research found that AMSC-EVs improved the survival rate and migration ability of HDFs and HaCaTs after UVB irradiation, alleviated cell senescence, reduced DNA damage, inhibited the production of ROS, and promoted the remodeling of extracellular matrix (ECM). Further research showed that after knocking down HSP27, the anti-aging/light protection ability of AMSC-EVs was significantly weakened. Overall, our data suggest that we have revealed the anti-photoaging effect of AMSC-EVs on HDFs and HaCaTs, which may be mediated by the delivery of HSP27.

This study evaluated the analgesic and anti-inflammatory effects of photobiomodulation (PBM) using 532 nm (green) and 660 nm (red) low-power lasers in an animal model of acute postoperative pain. Forty-five Wistar rats underwent a 1 cm surgical incision on the right hind paw and were randomly assigned to three groups: red laser (RL, 660 nm, 100 mW, 5 J, 167 J/cm²), green laser (GL, 532 nm, 70 mW, 4.97 J, 166 J/cm²), and control (LO, no irradiation). PBM was applied immediately and at 1-, 3-, 6-, and 24-h postsurgery, and pain levels were assessed using von Frey's electronic analgesimeter. Inflammatory cytokines (TNF-α, IL-1β, CGRP, and Substance P) were measured by ELISA. Results showed that both RL and GL were significantly more effective than the control group in reducing pain and inflammation. RL provided superior analgesia, increasing pain tolerance to 690.54 ± 50.20 g at 24 h, reaching levels comparable to the non-incised paw (p < 0.001). GL demonstrated greater anti-inflammatory effects, significantly reducing TNF-α levels at 1 h (p < 0.05) and 24 h and maintaining lower IL-1β and CGRP levels. RL also modulated Substance P levels, correlating with its stronger analgesic effect. These findings suggest that RL is preferable for direct pain relief, while GL is more effective in modulating inflammatory responses. Given the statistically significant improvement in pain control and inflammatory marker modulation, PBM using these wavelengths could be a valuable adjunct therapy for postoperative pain management and enhanced healing in surgical patients. Future studies should explore synergistic PBM protocols combining both wavelengths to optimize clinical outcomes.

Low-temperature (77 K) absorption and fluorescence spectra of 12 naturally occurring photosynthetic tetrapyrrole macrocycles have been recorded in a frozen glass (2-methyltetrahydrofuran). The compounds encompass distinct chromophore classes: porphyrin, chlorophyll c₂; chlorin, chlorophylls a, b, d, f and bacteriochlorophylls c, d, e, f; and bacteriochlorin, bacteriochlorophylls a, b, g. The spectra are compared with those of the same pigment in liquid solution (predominantly 2-methyltetrahydrofuran) at room temperature (293 K). The measured Stokes shifts at 77 K across the 12 macrocycles range from ~30 to 300 cm^-1. The spectral data in digital form are made available as part of the PhotochemCAD databases. Literature searches have revealed extensive published data for Chl a (often in biological matrices) but at best rather limited data for less common macrocycles. The availability of a systematic collection of curated spectral data collected at low temperature should be useful for a variety of assessments, including reconstruction of absorption spectra of (bacterio)chlorophyll-containing protein complexes, vibrational analysis of absorption and fluorescence spectra, and calculations where knowledge of energy levels is important.

Using visible light to drive NADH regeneration is an economically viable and environmentally sustainable technique. However, it necessitates a metal hydride (MH, [CpRh(bpy)(H₂O)]²⁺) as a synergist, and the high cost of the Rh noble metal significantly impedes the development and application of in-situ NADH regeneration. Therefore, in this study, single-atom Rh was immobilized onto the CdS QDs@SiO₂ combination via a consecutive ball-milling technique in combination with ionic layer adsorption and substitution. Subsequently, an enhanced photo-metal synergistic catalysis system for the recyclable regeneration of NADH was developed. In this composite, the single-atom Rh serves two main functions: It acts as an electrical medium and a metal catalyst, which regulates the activity and selectivity of the regenerated NADH. This study has successfully addressed the key scientific issues regarding the low electron transport rate and the recycling of the Rh noble metal during catalysis. Results confirm that single-atom Rh is successfully immobilized onto the CdS QDs@SiO₂ combination (Rh-CdS@SiO₂) and exhibits a faster electron transport and enhanced selectivity. Under blue light (LED, 420 nm) irradiation, the Rh-CdS@SiO₂ photo-metal catalyst shows a 25-fold increase in recyclable operability and achieves a 68% regeneration yield of NADH in just 4 min. Moreover, (S)-(+)-4-phenyl-2-butanol can be obtained with the regenerated NADH as the coenzyme of P450 enzyme catalysis.

Prolonged and chronic exposure to UV radiation is a risk factor for multiple skin cancers. As the incidence of UV-associated skin cancers continues to rise, there is a pressing need for a deeper understanding of the underlying mechanisms driving these pathologies. Polo-like kinases (PLKs), a family of enzymes consisting of five members (PLK1-PLK5), have been implicated in various aspects of skin carcinogenesis. The inhibition of PLKs is currently being explored as a potential strategy for cancer management. While much of the research has predominantly concentrated on PLK1, recent studies are increasingly shedding light on the role of other PLK family members, given their growing importance in cancer progression. Understanding the relationship between UV-associated skin cancers and PLKs could open new avenues for more effective management of skin cancers. In this review, we discuss the critical mechanisms associated with UV and PLKs in causing skin cancers, followed by the potential role of UV in modulating PLKs in different skin cancers. We also examine the prospect of targeting PLK signaling to enhance therapies for UV-induced skin cancer and improve patient responses. So far, there is not enough literature focused on the simultaneous effects of PLKs and UV using skin cancer models, emphasizing the need for further research to completely understand the role of PLKs in UV-induced skin carcinogenesis.

Exposure to the ultraviolet (UV) spectrum of sunlight poses a threat to terrestrial species. Nearly all species possess the nucleotide excision repair (NER) machinery, which can repair the helix-distorting DNA lesions induced by UV light. However, many species also have photolyase enzymes, which use near-UV and visible wavelengths of sunlight to directly reverse major classes of UV photoproducts. In eukaryotic cells, both of these repair pathways must efficiently locate and repair UV photoproducts present in chromatin. While genome-wide damage mapping methods have been used to extensively characterize how chromatin and ongoing transcription impact NER, much less is known about how photolyase enzymes navigate these obstacles to repair UV damage. Here, we highlight a recent article from our laboratory that used genome-wide sequencing methods to characterize how yeast photolyase repairs UV damage, both in NER-proficient and -deficient cells, and prevents UV-induced mutations.

Due to a limited penetration into skin and eyes combined with a broad germicidal effectiveness, far-UVC light (200-235 nm) has been proposed as an effective intervention for airborne pandemic control. Specifically, 222 nm light is not predicted to damage skin because it is primarily absorbed by the proteins in the superficial stratum corneum of the epidermis. Thus, it is hypothesized that the thickness of the stratum corneum is one of the most significant contributing factors to the risk of skin damage from exposure to far-UVC. From measurements of the stratum corneum thickness in live human skin biopsies, it was found that none of the donor demographics studied had an impact on the thickness of the stratum corneum. While multiple studies suggest that exposure to 222 nm is minimally damaging to skin, a few studies to date have investigated effects as a function of skin characteristics (e.g., individual's age and sex). In selected tissues, the induction of DNA damage following an acute exposure to 100 or 500 mJ/cm² from 222 nm light was analyzed as a function of donor demographics. The results agree with previous studies using other models of human skin and show that in human skin biopsies, 222 nm induces minor DNA damage only at high doses, especially in skin with low melanin content (phototype).