Impact of methylenetetrahydrofolate reductase C677T polymorphism on the efficacy of photodynamic therapy in patients with neovascular age-related macular degeneration

HIF-1α-dependent regulation of angiogenic factor expression in Müller cells by mechanical stimulation

Mechanical stress regulates various biological processes in cells, tissues, and organs as well as contributes to the pathogenesis of various diseases. The retina is subjected to mechanical stress imposed by intraocular pressure as well as by retinal hemorrhage and edema. Responses to mechanical stress have been studied in retinal pigment epithelial cells and Müller cells of the retina, with the former cells having been found to undergo a stress-induced increase in the expression of vascular endothelial growth factor (VEGF), which plays a key role in physiological and pathological angiogenesis in the retina. We here examined the effects of stretch stimulation on the expression of angiogenic factors in cultured human Müller cells. Reverse transcription and quantitative PCR analysis revealed that expression of the VEGF-A gene was increased by such stimulation in Müller cells, whereas that of the angiopoietin 1 gene was decreased. An enzyme-linked immunosorbent assay showed that stretch stimulation also increased VEGF secretion from these cells. Expression of the transcription factor HIF-1α (hypoxia-inducible factor-1α) was increased at both mRNA and protein levels by stretch stimulation, and the HIF-1α inhibitor CAY10585 prevented the effects of mechanical stress on VEGF-A gene expression and VEGF secretion. Furthermore, RNA-sequencing analysis showed that the expression of angiogenesis-related pathway genes was upregulated by stretch stimulation. Our results thus suggest that mechanical stress induces VEGF production in Müller cells in a manner dependent on HIF-1α, and that HIF-1α is therefore a potential therapeutic target for conditions such as diabetic retinopathy, age-related macular degeneration, and retinal vein occlusion.

Implanted, Wireless, Self-Powered Photodynamic Therapeutic Tablet Synergizes with Ferroptosis Inducer for Effective Cancer Treatment

The effective and targeted treatment of resistant cancer cells presents a significant challenge. Targeting cell ferroptosis has shown remarkable efficacy against apoptosis-resistant tumors due to their elevated iron metabolism and oxidative stress levels. However, various obstacles have limited its effectiveness. To overcome these challenges and enhance ferroptosis in cancer cells, we have developed a self-powered photodynamic therapeutic tablet that integrates a ferroptosis inducer (FIN), imidazole ketone erastin (IKE). FINs augment the sensitivity of photodynamic therapy (PDT) by increasing oxidative stress and lipid peroxidation. Furthermore, they utilize the Fenton reaction to supplement oxygen, generating a greater amount of reactive oxygen species (ROS) during PDT. Additionally, PDT facilitates the release of iron ions from the labile iron pool (LIP), accelerating lipid peroxidation and inducing ferroptosis. In vitro and in vivo experiments have demonstrated a more than 85% tumor inhibition rate. This synergistic treatment approach not only addresses the limitations of inadequate penetration and tumor hypoxia associated with PDT but also reduces the required medication dosage. Its high efficiency and specificity towards targeted cells minimize adverse effects, presenting a novel approach to combat clinical resistance in cancer treatment.

Novel Programmed Cell Death as Therapeutic Targets in Age-Related Macular Degeneration?

Age-related macular degeneration (AMD) is a leading cause of severe visual loss among the elderly. AMD patients are tormented by progressive central blurring/loss of vision and have limited therapeutic options to date. Drusen accumulation causing retinal pigment epithelial (RPE) cell damage is the hallmark of AMD pathogenesis, in which oxidative stress and inflammation are the well-known molecular mechanisms. However, the underlying mechanisms of how RPE responds when exposed to drusen are still poorly understood. Programmed cell death (PCD) plays an important role in cellular responses to stress and the regulation of homeostasis and diseases. Apart from the classical apoptosis, recent studies also discovered novel PCD pathways such as pyroptosis, necroptosis, and ferroptosis, which may contribute to RPE cell death in AMD. This evidence may yield new treatment targets for AMD. In this review, we summarized and analyzed recent advances on the association between novel PCD and AMD, proposing PCD's role as a therapeutic new target for future AMD treatment.

Predictive genetics for AMD: Hype and hopes for genetics-based strategies for treatment and prevention

Age-related macular degeneration (AMD) is a complex disease with multiple genetic and environmental risk factors. In the age of molecular genetics, many investigators have established a link between genes and development or progression of the disease. This later evolved to determine whether phenotypic features of AMD have distinct genetic profiles. Molecular genetics have subsequently been introduced as factors in risk assessment models, increasing the predictive value of these tools. Models seek to predict either development or progression of disease, and different AMD-related genes aid our understanding of these respective features. Several investigators have attempted to link molecular genetics with treatment response, but results and their clinical significance vary. Ocular and systemic biomarkers may interact with established genes, promising future routes of ongoing clinical assessment. Our understanding of AMD molecular genetics is not yet sufficient to recommend routine testing, despite its utility in the research setting. Clinicians must be wary of misusing population-based risk models from genetic and biomarker associations, as they are not necessarily relevant for individual counseling. This review addresses the known uses of predictive genetics, and suggests future directions.