The Dark Side of UV-Induced DNA Lesion Repair

Small particles, big effects: How nanoparticles can enhance plant growth in favorable and harsh conditions

By 2050, the global population is projected to reach 9 billion, underscoring the imperative for innovative solutions to increase grain yield and enhance food security. Nanotechnology has emerged as a powerful tool, providing unique solutions to this challenge. Nanoparticles (NPs) can improve plant growth and nutrition under normal conditions through their high surface-to-volume ratio and unique physical and chemical properties. Moreover, they can be used to monitor crop health status and augment plant resilience against abiotic stresses (such as salinity, drought, heavy metals, and extreme temperatures) that endanger global agriculture. Application of NPs can enhance stress tolerance mechanisms in plants, minimizing potential yield losses and underscoring the potential of NPs to raise crop yield and quality. This review highlights the need for a comprehensive exploration of the environmental implications and safety of nanomaterials and provides valuable guidelines for researchers, policymakers, and agricultural practitioners. With thoughtful stewardship, nanotechnology holds immense promise in shaping environmentally sustainable agriculture amid escalating environmental challenges.

Lapagyl mitigates UV-induced inflammation and immunosuppression via Foxp3+ Tregs and CCL pathway: A single-cell transcriptomics study

BACKGROUND

As the largest organ of the body, the skin is constantly subjected to ultraviolet radiation (UVR), leading to inflammations and changes that mirror those seen in chronological aging. Although various small molecule drugs have been explored for treating skin photoaging, they typically suffer from low stability and a high incidence of adverse reactions. Consequently, the continued investigation of photoaging treatments, particularly those utilizing herbal products, remains a critical clinical endeavor. One such herbal product, Lapagyl, is derived from the bark of the lapacho tree and possesses antioxidant efficacies that could be beneficial in combating skin photoaging.

PURPOSE

This research aimed to evaluate the efficacy of the herbal product Lapagyl in combating UVR-induced skin photoaging. Additionally, it sought to unravel the mechanisms by which Lapagyl promotes the regeneration of the skin extracellular matrix.

METHODS

To investigate whether Lapagyl can alleviate skin aging and damage, a UVR radiation model was established using SKH-1 hairless mice. The dorsal skins of these mice were evaluated for wrinkle formation, texture, moisture, transepidermal water loss (TEWL), and elasticity. Pathological assessments were conducted to determine Lapagyl's efficacy. Additionally, single-cell sequencing and spectrum analysis were employed to elucidate the working mechanisms and primary components of Lapagyl in addressing UVR-induced skin aging and injury.

RESULTS

Lapagyl markedly reduced UVR-induced wrinkles, moisture loss, and elasticity decrease in SKH-1 mice. Single-cell sequencing demonstrated that Lapagyl corrected the imbalance in cell proportions caused by UVR, decreased UVR-induced ROS expression, and protected basal and spinous cells from skin damage. Additionally, Lapagyl effectively prevented the entry of inflammatory cells into the skin by reducing CCL8 expression and curtailed the UVR-induced formation of Foxp3+ regulatory T cells (Tregs) in the skin. Both pathological assessments and ex vivo skin model results demonstrated that Lapagyl effectively reduced UVR-induced damage to collagen and elastin. Spectrum analysis identified Salidroside as the primary compound remaining in the skin following Lapagyl treatment. Taken together, our study elucidated the skin protection mechanism of the herbal product Lapagyl against UVR damage at the cellular level, revealing its immunomodulatory effects, with salidroside identified as the primary active compound for skin.

CONCLUSION

Our study provided a thorough evaluation of Lapagyl's protective effects on skin against UVR damage, delving into the mechanisms at the cellular level. We discovered that Lapagyl mitigates skin inflammation and immunosuppression by regulating Foxp3+ Tregs and the CCL pathway. These insights indicate that Lapagyl has potential as a novel therapeutic option for addressing skin photoaging.

Anti-aging Effects of Tirbanibulin 1% Ointment: A Real-Life Experience

INTRODUCTION

Tirbanibulin 1% ointment has been licensed to treat non-hyperkeratotic actinic keratosis (AKs) on the face and scalp in adults to ensure excellent patient tolerability due to the mild side effects and the brief application time compared to other topical therapies on the market. A growing body of evidence suggests that, beyond their primary function, the treatments for AKs and the cancerization field may inadvertently confer substantial cosmetic benefits to patients.

METHODS

We report a single-center retrospective case series of patients referred to the Dermatology Unit of the University Hospital of Messina, Italy, between February and December 2023 seeking treatment for AKs in the context of photodamaged areas in which the application of tirbanibulin 1% ointment induced, besides clearance of AKs, anti-aging effects on both skin texture and solar lentigos.

RESULTS

Seven patients affected by Olsen grade 1-2 AKs experienced a powerful rejuvenating effect in the treated areas, with a marked efficacy in skin lightening and clearance of solar lentigo.

CONCLUSIONS

Tirbanibulin 1% ointment seems able to improve skin aging as a desirable side effect at the site of application for AKs on chronic photodamaged skin. Such preliminary observation needs further confirmation in real-life studies on larger cohorts of patients, to explain the pathogenic mechanisms responsible for such aesthetically relevant results.

SUMO-Activating Enzyme Subunit 1 Is Associated with Poor Prognosis, Tumor Progression, and Radio-Resistance in Colorectal Cancer

Concurrent chemoradiotherapy is an effective treatment option for patients with low-grade colorectal cancer (CRC) in the local disease stage. At present, the principle of the Taiwan Medical Center is to treat CRC patients with combination radiotherapy and chemotherapy (high-dose 5-FU) for a period of about five weeks prior to surgery. Radical resection of the tumor is performed at least six to eight weeks after concurrent chemoradiotherapy (CCRT). However, this approach fails to produce the desired therapeutic effect in approximately 20% to 30% of patients, and such patients are unnecessarily exposed to the risks of radiation and drug toxicity posed by this therapy. Therefore, it is crucial to explore new biomarkers to predict the prognosis of CRC. SUMO-activating enzyme subunit 1 (SAE1) plays an important role in SUMOylation, a post-translational modification involved in cellular functions, such as cell proliferation, cell cycle, and apoptosis. In our study, to explore the clinical-pathological role of SAE1 protein in CRC, we evaluated the clinical data and paraffin sections from CRC patients. The expression of SAE1 was evaluated using immunohistochemical analysis, and clinical parameters were analyzed using chi-square and Kaplan-Meier survival tests. The results of in vitro proliferation and radiosensitive assays were compared between control groups and SAE1 siRNA groups. Western blotting was also used to detect the expressions of the SAE1, PARP, cyclin D1, p-NF-κB, and NF-κB proteins. Flow cytometry and colony formation assays were used to detect the effect of SAE-1 on radiosensitivity. In vivo, we detected the growth curve in a mouse xenograft model. The results showed that SAE-1 was revealed to be an independent prognostic biomarker of CRC. SAE1 knockdown inhibited CRC proliferation in vitro and in vivo, and led to the cleavage of PARP, downregulation of cyclin D1 protein expression, and downregulation of p-NF-κB/NF-κB. Additionally, SAE1 knockdown promoted radiosensitivity in CRC cells. Therefore, it was inferred that SAE1 may be used as a potential therapeutic target in CRC treatment.

Mechanisms of germ cell survival and plasticity in Caenorhabditis elegans

Animals constantly encounter environmental and physiological stressors that threaten survival and fertility. Somatic stress responses and germ cell arrest/repair mechanisms are employed to withstand such challenges. The Caenorhabditis elegans germline combats stress by initiating mitotic germ cell quiescence to preserve genome integrity, and by removing meiotic germ cells to prevent inheritance of damaged DNA or to tolerate lack of germline nutrient supply. Here, we review examples of germline recovery from distinct stressors - acute starvation and defective splicing - where quiescent mitotic germ cells resume proliferation to repopulate a germ line following apoptotic removal of meiotic germ cells. These protective mechanisms reveal the plastic nature of germline stem cells.

Immunotherapy for the Treatment of Squamous Cell Carcinoma: Potential Benefits and Challenges

Melanoma and nonmelanoma skin cancers (NMSCs) are recognized as among the most common neoplasms, mostly in white people, with an increasing incidence rate. Among the NMSCs, squamous cell carcinoma (SCC) is the most prevalent malignancy known to affect people with a fair complexion who are exposed to extreme ultraviolet radiation (UVR), have a hereditary predisposition, or are immunosuppressed. There are several extrinsic and intrinsic determinants that contribute to the pathophysiology of the SCC. The therapeutic modalities depend on the SCC stages, from actinic keratosis to late-stage multiple metastases. Standard treatments include surgical excision, radiotherapy, and chemotherapy. As SCC represents a favorable tumor microenvironment with high tumor mutational burden, infiltration of immune cells, and expression of immune checkpoints, the SCC tumors are highly responsive to immunotherapies. Until now, there are three checkpoint inhibitors, cemiplimab, pembrolizumab, and nivolumab, that are approved for the treatment of advanced, recurrent, or metastatic SCC patients in the United States. Immunotherapy possesses significant therapeutic benefits for patients with metastatic or locally advanced tumors not eligible for surgery or radiotherapy to avoid the potential toxicity caused by the chemotherapies. Despite the high tolerability and efficiency, the existence of some challenges has been revealed such as, resistance to immunotherapy, less availability of the biomarkers, and difficulty in appropriate patient selection. This review aims to accumulate evidence regarding the genetic alterations related to SCC, the factors that contribute to the potential benefits of immunotherapy, and the challenges to follow this treatment regime.

Trehalose Protects Keratinocytes against Ultraviolet B Radiation by Activating Autophagy via Regulating TIMP3 and ATG9A

Trehalose, a natural disaccharide, is synthesized by many organisms when cells are exposed to stressful stimuli. On the basis of its ability to modulate autophagy, trehalose has been considered an innovative drug for ameliorating many diseases, but its molecular mechanism is not well described. Previous findings demonstrated that trehalose plays a photoprotective role against ultraviolet (UV) B-induced damage through autophagy induction in keratinocytes. In this study, coimmunoprecipitation, label-free quantitative proteomic and parallel reaction monitoring, and western blot analysis demonstrated that trehalose promotes the interaction between tissue inhibitor of metalloproteinase (TIMP) 3 and Beclin1. Western blot and immunofluorescence staining analysis suggested that trehalose increases ATG9A localization in lysosomes and decreases its localization in the endoplasmic reticulum. Furthermore, in the presence or absence of UVB radiation, we evaluated the influence of TIMP3 and ATG9A small interfering RNA (siRNA) on the effect of trehalose on autophagy, cell death, migration, or interleukin-8 expression in keratinocytes, including HaCaT, A431, and human epidermal keratinocytes. The results revealed that in HaCaT cells, TIMP3 and ATG9A siRNA resulted in attenuation of trehalose-induced autophagy and inhibited cell death. In A431 cells, TIMP3 and ATG9A siRNA led to attenuation of trehalose-induced autophagy and cell death and inhibited migration. In human epidermal keratinocytes, trehalose-induced autophagy and inhibition of the interleukin-8 expression were blocked by ATG9A but not TIMP3 siRNA. In addition, the results of quantitative real-time PCR and immunohistochemistry analysis demonstrated the abnormal expression of TIMP3 and ATG9A in actinic keratosis and cutaneous squamous cell carcinoma skin tissues. These findings suggest the protective effects of trehalose in normal keratinocytes and its inhibitory effects on cancerous keratinocytes, possibly mediated by activation of autophagy and regulation of TIMP3 and ATG9A, providing the mechanistic basis for the potential use of trehalose in the prevention or treatment of UVB-induced skin diseases.

Genetic interaction of the histone chaperone hip1 + with double strand break repair genes in Schizosaccharomyces pombe

Schizosaccharomyces pombe hip1 + (human HIRA) is a histone chaperone and transcription factor involved in establishment of the centromeric chromatin and chromosome segregation, regulation of histone transcription, and cellular response to stress. We carried out a double mutant genetic screen of Δhip1 and mutations in double strand break repair pathway. We find that hip1 + functions after the MRN complex which initiates resection of blunt double strand break ends but before recruitment of the DNA damage repair machinery. Further, deletion of hip1 + partially suppresses sensitivity to DNA damaging agents of mutations in genes involved in Break Induced Replication (BIR), one mechanism of rescue of stalled or collapses replication forks ( rad51 + , cdc27 + ). Δhip1 also suppresses mutations in two checkpoint genes ( cds1 + , rad3 + ) on hydroxyurea a drug that stalls replication forks. Our results show that hip1 + forms complex interactions with the DNA double strand break repair genes and may be involved in facilitating communication between damage sensors and downstream factors.

Effects of TiO2-NPs pretreatment on UV-B stress tolerance in Arabidopsis thaliana

As the ozone hole in the North and South poles continues to increase, the entire ecosystem will face an environmental crisis caused by enhanced UV-B radiation. Considering the function of TiO₂ and the application of nanomaterials in agriculture, the effect of TiO₂-NPs on UV-B stress tolerance in Arabidopsis was investigated. The phenotype of plants was determined, and the expression patterns of antioxidant systems and related genes were analyzed. Modification of the antioxidant system and changes in the flavonoid content of plants were observed by histochemical staining. The effects of TiO₂-NPs and UV-B on mitosis were observed at the cellular level, and the degree of DNA damage was analyzed by the detection of CPDs content. The effects of TiO₂-NPs and UV-B on SOD isozymes were detected by SOD isozyme Native-PAGE electrophoresis. A laser confocal microscope was used to explore the protective mechanism of TiO₂-NPs against UV-B radiation. Results showed that pretreatment of TiO₂-NPs significantly alleviated the stress of UV-B radiation on plants. TiO₂-NPs activated the antioxidant system of plants, improved the activity of antioxidant enzymes, and promoted the synthesis of flavonoids. Moreover, TiO₂-NPs could effectively shield UV-B radiation to prevent the depolymerization of microtubules in plant cells. 10 mg/L of TiO₂-NPs is a safe and effective application dose, which has no biological toxicity to plants. Our research results reported for the first time that pretreatment of TiO₂-NPs could effectively alleviate UV-B stress to plants, providing new ideas for the application of nanomaterials in agriculture.

Behind the Scene: Exploiting MC1R in Skin Cancer Risk and Prevention

Melanoma and non-melanoma skin cancers (NMSCs) are the most frequent cancers of the skin in white populations. An increased risk in the development of skin cancers has been associated with the combination of several environmental factors (i.e., ultraviolet exposure) and genetic background, including melanocortin-1 receptor (MC1R) status. In the last few years, advances in the diagnosis of skin cancers provided a great impact on clinical practice. Despite these advances, NMSCs are still the most common malignancy in humans and melanoma still shows a rising incidence and a poor prognosis when diagnosed at an advanced stage. Efforts are required to underlie the genetic and clinical heterogeneity of melanoma and NMSCs, leading to an optimization of the management of affected patients. The clinical implications of the impact of germline MC1R variants in melanoma and NMSCs' risk, together with the additional risk conferred by somatic mutations in other peculiar genes, as well as the role of MC1R screening in skin cancers' prevention will be addressed in the current review.

Prospects for plant productivity: from the canopy to the nucleus

Population growth has been closely associated with agricultural production, since the first famine predicted by Malthus (1798) up to the Green Revolution of the past century. Today, we continue to face increasing demand for food and crop production (Tilman et al., 2011). Considering the combined caloric or protein content of the 275 major crops used directly as human foods or as livestock and fish feeds, Tilman et al. (2011) forecast a 100% increase in global demand for crops from 2005 to 2050. Meeting this demand with the lowest impact on the environment could be achieved by sustainable intensification of existing cropland with reduced land clearing (Tilman et al., 2011; Fischer and Connor, 2018).

Inflammatory Molecules Associated with Ultraviolet Radiation-Mediated Skin Aging

Skin is the largest and most complex organ in the human body comprised of multiple layers with different types of cells. Different kinds of environmental stressors, for example, ultraviolet radiation (UVR), temperature, air pollutants, smoking, and diet, accelerate skin aging by stimulating inflammatory molecules. Skin aging caused by UVR is characterized by loss of elasticity, fine lines, wrinkles, reduced epidermal and dermal components, increased epidermal permeability, delayed wound healing, and approximately 90% of skin aging. These external factors can cause aging through reactive oxygen species (ROS)-mediated inflammation, as well as aged skin is a source of circulatory inflammatory molecules which accelerate skin aging and cause aging-related diseases. This review article focuses on the inflammatory pathways associated with UVR-mediated skin aging.

All You Need Is Light. Photorepair of UV-Induced Pyrimidine Dimers

Although solar light is indispensable for the functioning of plants, this environmental factor may also cause damage to living cells. Apart from the visible range, including wavelengths used in photosynthesis, the ultraviolet (UV) light present in solar irradiation reaches the Earth's surface. The high energy of UV causes damage to many cellular components, with DNA as one of the targets. Putting together the puzzle-like elements responsible for the repair of UV-induced DNA damage is of special importance in understanding how plants ensure the stability of their genomes between generations. In this review, we have presented the information on DNA damage produced under UV with a special focus on the pyrimidine dimers formed between the neighboring pyrimidines in a DNA strand. These dimers are highly mutagenic and cytotoxic, thus their repair is essential for the maintenance of suitable genetic information. In prokaryotic and eukaryotic cells, with the exception of placental mammals, this is achieved by means of highly efficient photorepair, dependent on blue/UVA light, which is performed by specialized enzymes known as photolyases. Photolyase properties, as well as their structure, specificity and action mechanism, have been briefly discussed in this paper. Additionally, the main gaps in our knowledge on the functioning of light repair in plant organelles, its regulation and its interaction between different DNA repair systems in plants have been highlighted.