Photo-enhancement of macrophage phagocytic activity via Rac1-mediated signaling pathway: Implications for bacterial infection.
Lu Cuixia,Fan Zhijin,Xing Da
The international journal of biochemistry & cell biology
Phagocytosis and the subsequent destruction of invading pathogens by macrophages are indispensable steps in host immune responses to microbial infections. Low-power laser irradiation (LPLI) has been found to exert photobiological effects on immune responses, but the signaling mechanisms underlying this photobiomodulation of phagocytosis remains largely unknown. Here, we demonstrated for the first time that LPLI enhanced the phagocytic activity of macrophages by stimulating the activation of Rac1. The overexpression of constitutively activated Rac1 clearly enhanced LPLI-induced phagocytosis, whereas the overexpression of dominant negative Rac1 exerted the opposite effect. The phosphorylation of cofilin was involved in the effects of LPLI on phagocytosis, which was regulated by the membrane translocation and activation of Rac1. Furthermore, the photoactivation of Rac1 was dependent on the Src/PI3K/Vav1 pathway. The inhibition of the Src/PI3K pathway significantly suppressed LPLI-induced actin polymerization and phagocytosis enhancement. Additionally, LPLI-treated mice exhibited increased survival and a decreased organ bacterial load when challenged with Listeria monocytogenes, indicating that LPLI enhanced macrophage phagocytosis in vivo. These findings highlight the important roles of the Src/PI3K/Vav1/Rac1/cofilin pathway in regulating macrophage phagocytosis and provide a potential strategy for treating phagocytic deficiency via LPLI.
10.1016/j.biocel.2016.06.010
In vitro tools for photobiological testing: molecular responses to simulated solar UV of keratinocytes growing as monolayers or as part of reconstructed skin.
Marrot Laurent,Planel Emilie,Ginestet Anne-Claire,Belaïdi Jean-Philippe,Jones Christophe,Meunier Jean-Roch
Photochemical & photobiological sciences : Official journal of the European Photochemistry Association and the European Society for Photobiology
Epidermal keratinocytes are critical targets for UV-induced genotoxicity as their transformation by sunlight overexposure can lead to skin cancer such as basal cell carcinoma (BCC) and squamous cell carcinoma (SCC). Therefore, assessment of photoprotection should involve early markers associated with DNA photodamage. Here, the same normal human keratinocytes either in monoculture (KC) or in full thickness reconstructed skin (RS) were compared with respect to their response to simulated solar UV (SSUV) exposure. Irradiation conditions (spectral power distribution and doses) were designed to mimic environmental zenithal UV from sunlight. At doses where survival was higher than 80%, comet assay showed more single strand breaks (SSB) and cyclobutane pyrimidine dimers (CPD) in keratinocytes in RS than in KC one hour post-exposure. The transcription factor p53 was activated in both models. While in KC p53 accumulation displayed a linear dose-dependency up to 24 h post-exposure, in RS it followed a bell-shaped profile and reverted to its basal rate. QRT-PCR demonstrated that among genes controlled by p53, P21 and MDM2 were clearly induced by SSUV in KC, whereas GADD45 expression was strongly and almost exclusively up-regulated in RS. Nrf2-dependent antioxidant genes (Ferritin light chain, NQO1) were only induced in RS, yet at low doses for NQO1. In vitro models such as KC or RS allowing the development of quantitative methodologies should be used as surrogates for in vivo tests assessing photogenotoxicity.
10.1039/b9pp00145j
The importance of the depth distribution of melanin in skin for DNA protection and other photobiological processes.
Nielsen Kristian P,Zhao Lu,Stamnes Jakob J,Stamnes Knut,Moan Johan
Journal of photochemistry and photobiology. B, Biology
Melanin pigments are important regulators for the evolution of essential functions of human skin. The concentration of melanin, as well as its depth distribution, is strongly affected by ultraviolet radiation. In un-tanned skin, melanin pigments are found only in the basal layer of the epidermis, while in tanned skin it is distributed throughout the epidermis. So far, mainly the amount of melanin, and not its distribution, has been considered in view of skin photobiology. With an advanced radiative transfer model we investigate, for the first time, how the depth distribution of melanin influences the amount of ultraviolet radiation that reaches living cells in the epidermis, and thus can damage the DNA in the cells. The simulations are performed for average pigmented skins (type III-IV). A surprisingly large factor, up to 12, is found between the ultraviolet protection of skin with melanin distributed throughout the epidermis, and skin with melanin only in the basal layer of the epidermis. We also show that the synthesis of previtamin D3, in skin, can vary with more than 100% if the depth distribution of melanin is changed, while the degradation of folate in dermal blood is almost un-affected by variations in the melanin depth distribution.
10.1016/j.jphotobiol.2005.11.008
Non-melanoma skin cancer, sun exposure and sun protection.
Calzavara-Pinton P,Ortel B,Venturini M
Giornale italiano di dermatologia e venereologia : organo ufficiale, Societa italiana di dermatologia e sifilografia
The incidence of skin tumors including squamous cell carcinoma (SCC), and its biological precursor, the actinic keratosis, and basal cell carcinoma (BCC) often named together non-melanoma skin cancer (NMSC) is growing all over the world in people of Caucasian ancestry. A plenty of clinical and epidemiological studies have demonstrated the causal relationship with high cumulative solar dosages and number of sunburns, although the hazard may be different for different tumors according to the modalities of ultraviolet (UV) exposure. BCC is much more strongly related to measures of intermittent ultraviolet exposure (particularly those of childhood or adolescence) than to measures of cumulative exposure. In contrast, SCC is more strongly related to constant or cumulative sun exposure. Photobiological studies have clarified that sunlight and UVB radiation are complete carcinogens for AK and SCC although the relationship with UVA exposure is much less known. Also the likelihood of BCC has been related to either sunburns and high lifetime solar, UVA and UVB cumulative doses but the pathogenetic pathways of both UVB and UVA radiation for BCC development need to be clarified so far. The lack of a complete knowledge of the photocarcinogenic pathways of keratinocytes has contributed to the limited results of solar photoprotection strategies, beside the limitations of the available sunscreens and present EU regulations.
Functional regulation of tyrosinase and LAMP gene family of melanogenesis and cell death in immortal murine melanocytes after repeated exposure to ultraviolet B.
The British journal of dermatology
This study characterizes the induction of melanogenesis and the expression of tyrosinase, tyrosinase-related protein (TRP) and lysosome-associated membrane protein (LAMP) gene families in the cultured melanocyte lines of non-agouti mice with four major genetic loci, i.e. melan-a2 (black, wild type), melan-b (brown, TRP-1 mutation), melan-s (black, piebaldism mutation) and melan-c (white, tyrosinase mutation) in response to repeated exposure to ultraviolet (UV) B (5 mJ/cm2, 7 consecutive days). Electron microscopy showed that new melanogenesis was induced in melan-a2, melan-s and melan-b melanocytes. Melan-a2, melan-s and melan-b showed an almost twofold increase in tyrosinase activity and gene expression with increased synthesis of melanosomes, although melan-b showed a minimum increase in tyrosinase activity. There was a twofold upregulation of LAMP-1 mRNA but no alteration in LAMP-2 and LAMP-3 mRNA expression in melan-a2, while there was no alteration in LAMP-1 mRNA expression but increased expression of LAMP-2 and LAMP-3 mRNA in melan-s, LAMP-3 showing a higher increase. Melan-b cells showed the same gene expression of LAMP-1, LAMP-2 and LAMP-3 as that of non-UV exposed cells. All three lines, however, exhibited simultaneously cell death, melan-b reaching the highest rate of cell death (96.5%). In contrast, melan-c, which did not have any tyrosinase activity with failure of melanogenesis induction, expressed all the mRNAs of the tyrosinase and LAMP gene families, but was not associated with any significant melanocyte death. Our study indicated: (i) that melanogenesis induction and melanocyte death are two photobiological processes occurring simultaneously after repeated UVB exposure, (ii) that in response to an upregulation of tyrosinase mRNA and enzymic activity, there was a co-ordinated upregulation of the LAMP-1 gene in wild type melan-a2, while no upregulation was found in melan-s and melan-b mutants, and (iii) that UV-induced melanocyte death is related to the upregulation of the tyrosinase gene, induction of new melanogenesis and mutation of the TRP-1 gene in immortal murine melanocytes.
10.1046/j.1365-2133.1998.02356.x
Involvement of cytokines, DNA damage, and reactive oxygen intermediates in ultraviolet radiation-induced modulation of intercellular adhesion molecule-1 expression.
Krutmann J,Grewe M
The Journal of investigative dermatology
By virtue of its capacity to serve as a counter-receptor for lymphocyte function-associated antigen-1, intercellular adhesion molecule-1 (ICAM-1) plays a pivotal role in generation and maintenance of immunologic/inflammatory skin diseases by mediating leukocyte/keratinocyte adhesion. Ultraviolet radiation (UVR) may exert both antiinflammatory effects (e.g., UV phototherapy) and proinflammatory effects (e.g., triggering of photosensitive skin diseases) on human skin. Recent evidence indicates that UVR-induced changes of keratinocyte ICAM-1 expression constitute the molecular basis for these ambivalent properties of UVR, as UVR is able to exert two separate and even opposite effects on ICAM-1 expression. As an antiinflammatory effect, UVR may inhibit cytokine-induced up-regulation of keratinocyte ICAM-1 expression, whereas induction of ICAM-1 expression by UVR represents a proinflammatory activity. This latter effect is mediated by an autocrine mechanism involving interleukin (IL)-1 alpha. In this autocrine system, UVR exposure of human keratinocytes leads to the release of IL-1 alpha, which in turn up-regulates the expression of IL-1 receptor type 1 molecules on the keratinocyte surface, thereby increasing the sensitivity of these cells toward IL-1 alpha. As a consequence, irradiated keratinocytes are capable of responding to endogenously produced IL-1 alpha by increasing ICAM-1 expression. Modulation of keratinocyte ICAM-1 expression after UVR exposure may be observed after both short-wave UVR (UVB; 280-320 nm) and long-wave UVR (UVA1; 340-400 nm). The photobiologic mechanisms underlying UVB versus UVA1 radiation-induced ICAM-1 modulation have been found to differ. Although not completely delineated, UVB radiation-induced modulation of ICAM-1 expression appears to be mediated via the induction of DNA damage, whereas UVA1 radiation effects involve the generation of reactive oxygen intermediates.
10.1111/1523-1747.ep12316095
Unexpected dose response of HaCaT to UVB irradiation.
Chang Rong-Shing,Chen Chi-Shuo,Huang Ching-Lung,Chang Chiu-Ting,Cui Yujia,Chung Wei-Ju,Shu Wun-Yi,Chiang Chi-Shiun,Chuang Chun-Yu,Hsu Ian C
In vitro cellular & developmental biology. Animal
Application of high-dosage UVB irradiation in phototherapeutic dermatological treatments present health concerns attributed to UV-exposure. In assessing UV-induced photobiological damage, we investigated dose-dependent effects of UVB irradiation on human keratinocyte cells (HaCaT). Our study implemented survival and apoptosis assays and revealed an unexpected dose response wherein higher UVB-dosage induced higher viability. Established inhibitors, such as AKT- (LY294002), PKC- (Gö6976, and Rottlerin), ERK- (PD98059), P38 MAPK- (SB203580), and JNK- (SP600125), were assessed to investigate UV-induced apoptotic pathways. Despite unobvious contributions of known signaling pathways in dose-response mediation, microarray analysis identified transcriptional expression of UVB-response genes related to the respiratory-chain. Observed correlation of ROS-production with UVB irradiation potentiated ROS as the underlying mechanism for observed dose responses. Inability of established pathways to explain such responses suggests the complex nature underlying UVB-phototherapy response.
10.1007/s11626-018-0280-4
A review of the effect of the light environment of the VDT workspace on the "learning to learn" effect of video game training.
Frontiers in neuroscience
In recent years, the role of video games in enhancing brain plasticity and learning ability has been verified, and this learning transfer is known as the "learning to learn" effect of video game training. At the same time, against the background of healthy lighting, the influence of non-visual effects of light environment on the human rhythmic system has been gradually confirmed. As a special operation form of Visual Display Terminal (VDT) operation, video game training has a high dependence on VDT equipment and the VDT screen, and the background usually has a huge difference in brightness. Compared with the light environment of ordinary operation space, the light environment of VDT operation space is more complex. This complex light environment's non-visual effects cause human emotions, alertness, fatigue, cognitive ability, and other changes, which may affect the efficiency of the "learning to learn" effect of video game training. This article focuses on the impact of the light environment in the VDT workspace on the "learning to learn" effect of video game training. It first traces the factors that trigger the "learning to learn" effect of video game training, that is, the improvement of people's attention, perception, and cognitive ability. Then, the influencing mechanism and the evaluation method of the VDT workspace space light environment on the human rhythm system are discussed based on the basic theory of photobiological effect. In addition, the VDT display lighting light time pattern, photophysical properties, regulation, and protection mechanism on the human rhythm system are studied to demonstrate the VDT workspace light environment's special characteristics. Finally, combined with the progress of artificial lighting technology and the research results of health lighting, given the "learning to learn" effect of video game training, some thoughts on the design of the light environment of the workplace and future research directions are presented.
10.3389/fnins.2023.1093602
Photobiomodulation and diffusing optical fiber on spinal cord's impact on nerve cells from normal spinal cord tissue in piglets.
Zuo Xiaoshuang,Liang Zhuowen,Zhang Jiawei,Wang Shuang,Zheng Qiao,Ma Yangguang,Li Penghui,Ding Tan,Hu Xueyu,Wang Zhe
Lasers in medical science
Experts have proven that photobiological regulation therapy for spinal cord injury promotes the spinal repair following injury. The traditional irradiation therapy mode is indirect (percutaneous irradiation), which could significantly lower the effective use of light energy. In earlier studies, we developed an implantable optical fiber that one can embed above the spinal cord lamina, and the light directly is cast onto the surface of the spinal cord in a way that can dramatically improve energy use. Nonetheless, it remains to be seen whether near-infrared light diffused by embedded optical fiber can have side effects on the surrounding nerve cells. Given this, we implanted optical fiber on the lamina of a normal spinal cord to observe the structural integrity of the tissue using morphological staining; we also used immunohistochemistry to detect inflammatory factors. Considering the existing studies, we meant to determine that the light energy diffused by embedded optical fiber has no side effect on the normal tissue. The results of this study will lay a foundation for the clinical application of the treatment of spinal cord injury by near-infrared light irradiation.
10.1007/s10103-020-03231-8
Photobiological effects of UVA and UVB light in zebrafish embryos: evidence for a competent photorepair system.
Journal of photochemistry and photobiology. B, Biology
The consequences of UVB and UVA irradiation on hatch rate, mortality, and malformation were studied in embryonic zebrafish (Danio rerio). The use of zebrafish embryos has expanded from traditional developmental models to diverse studies, including many techniques utilizing light exposure. To characterize useful indicators of photodamage, the responses and threshold limits of UV radiation as a function of embryonic stage and fish source were evaluated. Significant differences in UVB susceptibility were observed in embryos at 3, 6-7, 12, and 24h post-fertilization (hpf), with the 1000-cell stage (3 hpf) having greatest tolerance to UVB. Embryos derived from zebrafish raised in outdoor ponds were more tolerant to UVB than were embryos from laboratory-raised fish. Combinations of UVB and UVA exposure were used to confirm the presence of a competent photorepair system in zebrafish that could return otherwise malformed embryos to a normal phenotype. Overall, embryonic zebrafish had large tolerances (LD(50) of 850 J/cm(2)) to UVA, confirming their suitability for photoactivation and photorepair studies.
10.1016/j.jphotobiol.2007.07.002
Rapid solid-liquid dynamic extraction of Jan ex Guss. aerial parts: influence on the photobiological and antioxidant properties.
Natural product research
Jan ex Guss. (Apiaceae) is a perennial plant native to Italy and Northwestern Africa. This species is known for its content in furanocoumarins, and the methanolic extract obtained with maceration previously demonstrated significant phototoxicity on 375 melanoma cells. Here, in order to better explain the biological effects, the apoptotic responses on melanoma cancer cell line were verified. The aerial parts were extracted with methanol through an innovative solid-liquid extraction technology, the Naviglio extractor®, and the raw extract was tested for its photobiological properties on human melanoma C32 cells irradiated with UVA light. The antioxidant potential was assessed as well. The sample exerted a concentration-dependent photocytotoxic activity (IC value = 3.00 ± 0.16 µg/mL). In line with these evidences, in C32-treated cells subjected to UV irradiation, further data have reported an up-regulation of p53 and PARP, both proteins involved in apoptotic response and DNA repair.
10.1080/14786419.2023.2295921
Experimental study on the safety of photobiologic regulation therapy in the treatment of some non-epidermal tumors.
Lasers in medical science
This study investigates the impact of Photobiomodulation (PBM) at different wavelengths on non-superficial cancer cells. Utilizing three laser protocols (650 nm, 810 nm, and 915 nm), the research explores cytotoxic effects, ROS generation, and cell migration. Results reveal varied responses across cell lines, with 810 nm PBM inducing significant ROS levels and inhibiting PAN-1 cell migration. The study suggests potential therapeutic applications for PBM in non-superficial cancers, emphasizing the need for further exploration in clinical settings.
10.1007/s10103-024-04121-z
Method for Investigation of Photobiological Effects of Light on Human Skin Cells Mediated by Low Doses of Light.
Mignon Charles,Uzunbajakava Natallia E
Methods in molecular biology (Clifton, N.J.)
Driven by evolution, human skin cells have developed an extraordinary ability both to sense and to respond to the photons of sunlight through a plethora of photobiological interactions, activating intracellular signalling cascades and regulating skin cells homeostasis. It has recently been reported that some of these photobiological responses triggered by low levels of light (or the so-called photobiomodulation) could initiate beneficial therapeutic effects. Identification of these effective light-based therapeutic solutions requires in-depth understanding of the parameter space. The physical, biological, and chemical conditions that need to be fulfilled to facilitate such positive photobiological effects are to be carefully deciphered. Here, we provide the protocols that were specifically developed to investigate multidimensional parameter space driving photobiological interactions triggered by light (photobiomodulation) in the skin cells. The approach is based on the so-called design of experiment (DoE), a statistical method, which allows for the investigation of multidimensional parameters landscapes. This goes hand in hand with sharing practical tips for the design of light-based devices inducing these effects. To exemplify practical applications of the developed methods and light-based devices, we disclose experimental data sets and emphasize robustness and reproducibility of the results.
10.1007/978-1-0716-0648-3_22
The Value of Photo Biological Regulation Based on Nano Semiconductor Laser Technology in the Treatment of Hypertension Fundus Disease.
Hu Xingui,Zhou Linan,Wang Huifeng,Gao Yuanpeng,Gao Yan
Journal of nanoscience and nanotechnology
With the development of nanometer semiconductor laser technology, due to the wide range of photobiological regulation and non-invasive advantages, it is widely used in clinical research, including reducing pain, accelerating wound healing, nerve injury repair and regeneration. Increase tissue blood flow, improve anxiety and depression, and treat Parkinson's and retinal diseases. However, in many studies, the role of photobiological regulation is still controversial. There are two main problems, one is that the mechanism of photo biological regulation is not fully understood, and the other is that the specific parameters are not uniform in different treatments, such as wavelength density, power density, pulse, treatment timing, and number of treatments. In this paper, through the second question, the parameters of low-energy near-infrared light (810 nm semiconductor laser) in the treatment of fundus diseases are the main research objects. Based on understanding the parameters of low-energy lasers, cyan blue is irradiated with different energy near-infrared light. Data analysis of the actual energy obtained after the retina of the rabbit and observation and research on the cell morphology of each layer of the retina, to obtain relatively safe treatment parameters for the retina, provide theoretical data for near-infrared light in the treatment of clinical fundus disease, and make it safer to use in clinical treatment.
10.1166/jnn.2021.18698
Opsin evolution in the Ambulacraria.
D'Aniello S,Delroisse J,Valero-Gracia A,Lowe E K,Byrne M,Cannon J T,Halanych K M,Elphick M R,Mallefet J,Kaul-Strehlow S,Lowe C J,Flammang P,Ullrich-Lüter E,Wanninger A,Arnone M I
Marine genomics
Opsins--G-protein coupled receptors involved in photoreception--have been extensively studied in the animal kingdom. The present work provides new insights into opsin-based photoreception and photoreceptor cell evolution with a first analysis of opsin sequence data for a major deuterostome clade, the Ambulacraria. Systematic data analysis, including for the first time hemichordate opsin sequences and an expanded echinoderm dataset, led to a robust opsin phylogeny for this cornerstone superphylum. Multiple genomic and transcriptomic resources were surveyed to cover each class of Hemichordata and Echinodermata. In total, 119 ambulacrarian opsin sequences were found, 22 new sequences in hemichordates and 97 in echinoderms (including 67 new sequences). We framed the ambulacrarian opsin repertoire within eumetazoan diversity by including selected reference opsins from non-ambulacrarians. Our findings corroborate the presence of all major ancestral bilaterian opsin groups in Ambulacraria. Furthermore, we identified two opsin groups specific to echinoderms. In conclusion, a molecular phylogenetic framework for investigating light-perception and photobiological behaviors in marine deuterostomes has been obtained.
10.1016/j.margen.2015.10.001
[Reciprocity regulation in photobiology. An overview].
Schindl A,Rosado-Schlosser B,Trautinger F
Der Hautarzt; Zeitschrift fur Dermatologie, Venerologie, und verwandte Gebiete
According to the rule of Bunsen and Roscoe, a photochemical reaction is directly proportional to the total energy dose, irrespective of the time over which this dose is delivered. To date few studies have addressed the validity of this rule in experimental and applied photobiology. Most of these data point to the fact that the rule of reciprocity is invalid or of limited validity for many photobiological reactions. For UV-induced cell death, photocarcinogenesis, psoralen photochemistry, and the effects of low level laser radiation it has been shown that at a constant total dose, the intensity of the source is a major factor that determines quality and quantity of the response. In clinical photomedicine systematic investigations on the reciprocity of exposure time and radiation intensity are lacking. Such studies are urgently needed since it can be concluded from experimental evidence, that their results might lead to therapeutic regimens with an improved therapeutic index, i.e. maximized therapeutic efficacy with minimized adverse reactions.
Photobiological implications of melanin photoprotection after UVB-induced tanning of human skin but not UVA-induced tanning.
Coelho Sergio G,Yin Lanlan,Smuda Christoph,Mahns Andre,Kolbe Ludger,Hearing Vincent J
Pigment cell & melanoma research
Repetitive suberythemal UVA and/or UVB exposures were used to generate comparable UV-induced tans in human skin over the course of 2 weeks. To evaluate the potential photoprotective values of those UVA- and/or UVB- induced tans and to avoid the confounding issue of residual UV-induced DNA damage, we waited 1 week before challenging those areas with a 1.5 MED of UVA+UVB after which we measure DNA damage. The results show that the type of UV used to induce skin pigmentation affects the redistribution of melanin in the skin and/or de novo melanin synthesis. The UVA-induced tans failed to even provide a minimal SPF of 1.5, which suggests that producing a tan with UVA-rich sunlamps prior to a holiday or vacation is completely counterproductive.
10.1111/pcmr.12331
Light, photoreceptors, and circadian clocks.
Foster Russell G,Hankins Mark W,Peirson Stuart N
Methods in molecular biology (Clifton, N.J.)
Research over the past decade has focused increasingly on the photoreceptor mechanisms that regulate the circadian system in all forms of life. Some of the results to emerge are surprising. For example, the rods and cones within the mammalian eye are not required for the alignment (entrainment) of circadian rhythms to the dawn-dusk cycle. There exists a population of directly light-sensitive ganglion cells within the eye that act as brightness detectors; these regulate both circadian rhythms and melatonin synthesis. An understanding of these "circadian photoreceptor" pathways, and the features of the light environment used for entrainment, have been and will continue to be heavily dependent on the appropriate use and measurement of light stimuli. Furthermore, if results from different laboratories, or species, are to be compared in any meaningful sense, standardized methods for light measurement and manipulation need to be adopted by circadian biologists. To this end, we describe light measurement in terms of both radiometric and photometric units and consider the appropriate use of light as a stimulus in circadian experiments. In addition, the construction of action spectra has been very helpful in associating photopigments with particular responses in a broad range of photobiological systems. Because the identity of the photopigments mediating circadian responses to light are often not known, we have also taken this opportunity to provide a step-by-step approach to conducting action spectra, including the construction of irradiance response curves, the calculation of relative spectral sensitivities, photopigment template fitting, and the underlying assumptions behind this approach. The aims of this chapter are to provide an accessible introduction to photobiological methods and explain why these approaches need to be applied to the study of circadian systems.
10.1007/978-1-59745-257-1_1
Psoralen-protein photochemistry--a forgotten field.
Schmitt I M,Chimenti S,Gasparro F P
Journal of photochemistry and photobiology. B, Biology
8-Methoxypsoralen in combination with long wavelength ultraviolet light is employed for the treatment of several cutaneous disorders, such as psoriasis, vitiligo and mycosis fungoides. It is common to attribute the efficacy of the photochemotherapy to the formation of psoralen DNA photoadducts. Thus, the main research effort has been directed towards the elucidation of nucleic acid photochemistry and related subsequent events (mutagenicity, toxicity). However, psoralens have been shown to undergo photoaddition reactions with other cellular components. In this review the status of psoralen-DNA photobiology is briefly summarized. The main focus, however, is on a survey of psoralen photochemical modification of proteins and the ways by which these additional photobiological events can impact the antigenicity and potentially immunogenicity of treated cells. Some preliminary results show the extent of psoralen-amino acid photoadduct formation and their impact on enzymatic processing.
Signalling and gene regulation in response to ultraviolet light.
Ulm Roman,Nagy Ferenc
Current opinion in plant biology
In contrast to phytochrome-, cryptochrome- and phototropin-sensing systems, about which considerable knowledge has accumulated, the ultraviolet-B (UVB) photoreceptor is not yet known at the molecular level. Information about the downstream signalling events that underlie UVB-provoked physiological responses is limited. Recent whole-genome transcript profiling, isolation of mutants that are impaired in specific UVB-induced responses and detailed photobiological studies suggest that responses that are triggered by shorter wavelength UVB and longer wavelength UVB are mediated by two different sensory systems. The bZIP transcription factor HY5 was recently identified as an important player in the long-wavelength UVB-induced signal transduction cascade. Advances in the development of luciferase-reporter lines will make it feasible to perform high-throughput genetic screens to isolate novel mutants that are impaired in sensing or transducing signals downstream of the putative UVB photoreceptor(s).
10.1016/j.pbi.2005.07.004
Photodecomposition of vitamin A and photobiological implications for the skin.
Fu Peter P,Xia Qingsu,Yin Jun Jie,Cherng Shu-Hui,Yan Jian,Mei Nan,Chen Tao,Boudreau Mary D,Howard Paul C,Wamer Wayne G
Photochemistry and photobiology
Vitamin A (retinol), an essential human nutrient, plays an important role in cellular differentiation, regulation of epidermal cell growth and normal cell maintenance. In addition to these physiological roles, vitamin A has a rich photochemistry. Photoisomerization of vitamin A, involved in signal transduction for vision, has been extensively investigated. The biological effects of light-induced degradation of vitamin A and formation of reactive species are less understood and may be important for light-exposed tissues, such as the skin. Photochemical studies have demonstrated that excitation of retinol or its esters with UV light generates a number of reactive species including singlet oxygen and superoxide radical anion. These reactive oxygen species have been shown to damage a number of cellular targets, including lipids and DNA. Consistent with the potential for damaging DNA, retinyl palmitate has been shown to be photomutagenic in an in vitro test system. The results of mechanistic studies were consistent with mutagenesis through oxidative damage. Vitamin A in the skin resides in a complex environment that in many ways is very different from the chemical environment in solution and in in vitro test systems. Relevant clinical studies or studies in animal models are therefore needed to establish whether the pro-oxidant activity of photoexcited vitamin A is observed in vivo, and to assess the related risks.
10.1562/2006-10-23-IR-1065
Blue light regulation in Neurospora crassa.
Linden H,Ballario P,Macino G
Fungal genetics and biology : FG & B
The fungus Neurospora crassa has been shown to be a paradigm for photobiological, biochemical, and genetic studies of blue light perception and signal transduction. Several different developmental and morphological processes of Neurospora are regulated by blue light and can be divided into early and late blue light responses. The characterization of two central regulator proteins of blue light signal transduction in Neurospora crassa, WC1 and WC2, and the isolation of light-regulated genes, indicate transcriptional control as a central step in blue light signalling.
10.1006/fgbi.1997.1013
The Mechanisms and Efficacy of Photobiomodulation Therapy for Arthritis: A Comprehensive Review.
International journal of molecular sciences
Rheumatoid arthritis (RA) and osteoarthritis (OA) have a significant impact on the quality of life of patients around the world, causing significant pain and disability. Furthermore, the drugs used to treat these conditions frequently have side effects that add to the patient's burden. Photobiomodulation (PBM) has emerged as a promising treatment approach in recent years. PBM effectively reduces inflammation by utilizing near-infrared light emitted by lasers or LEDs. In contrast to photothermal effects, PBM causes a photobiological response in cells, which regulates their functional response to light and reduces inflammation. PBM's anti-inflammatory properties and beneficial effects in arthritis treatment have been reported in numerous studies, including animal experiments and clinical trials. PBM's effectiveness in arthritis treatment has been extensively researched in arthritis-specific cells. Despite the positive results of PBM treatment, questions about specific parameters such as wavelength, dose, power density, irradiation time, and treatment site remain. The goal of this comprehensive review is to systematically summarize the mechanisms of PBM in arthritis treatment, the development of animal arthritis models, and the anti-inflammatory and joint function recovery effects seen in these models. The review also goes over the evaluation methods used in clinical trials. Overall, this review provides valuable insights for researchers investigating PBM treatment for arthritis, providing important references for parameters, model techniques, and evaluation methods in future studies.
10.3390/ijms241814293