TFEB attenuates hyperglycemia-induced retinal capillary endothelial cells injury via autophagy regulation

Age-related driving mechanisms of retinal diseases and neuroprotection by transcription factor EB-targeted therapy

Retinal aging has been recognized as a significant risk factor for various retinal disorders, including diabetic retinopathy, age-related macular degeneration, and glaucoma, following a growing understanding of the molecular underpinnings of their development. This comprehensive review explores the mechanisms of retinal aging and investigates potential neuroprotective approaches, focusing on the activation of transcription factor EB. Recent meta-analyses have demonstrated promising outcomes of transcription factor EB-targeted strategies, such as exercise, calorie restriction, rapamycin, and metformin, in patients and animal models of these common retinal diseases. The review critically assesses the role of transcription factor EB in retinal biology during aging, its neuroprotective effects, and its therapeutic potential for retinal disorders. The impact of transcription factor EB on retinal aging is cell-specific, influencing metabolic reprogramming and energy homeostasis in retinal neurons through the regulation of mitochondrial quality control and nutrient-sensing pathways. In vascular endothelial cells, transcription factor EB controls important processes, including endothelial cell proliferation, endothelial tube formation, and nitric oxide levels, thereby influencing the inner blood-retinal barrier, angiogenesis, and retinal microvasculature. Additionally, transcription factor EB affects vascular smooth muscle cells, inhibiting vascular calcification and atherogenesis. In retinal pigment epithelial cells, transcription factor EB modulates functions such as autophagy, lysosomal dynamics, and clearance of the aging pigment lipofuscin, thereby promoting photoreceptor survival and regulating vascular endothelial growth factor A expression involved in neovascularization. These cell-specific functions of transcription factor EB significantly impact retinal aging mechanisms encompassing proteostasis, neuronal synapse plasticity, energy metabolism, microvasculature, and inflammation, ultimately offering protection against retinal aging and diseases. The review emphasizes transcription factor EB as a potential therapeutic target for retinal diseases. Therefore, it is imperative to obtain well-controlled direct experimental evidence to confirm the efficacy of transcription factor EB modulation in retinal diseases while minimizing its risk of adverse effects.

Acetylation of MOB1 mediates polyphyllin II-reduced lysosome biogenesis in breast cancer by promoting the cytoplasmic retention of the YAP/TFEB coactivator complex

BACKGROUND

Autophagy‒lysosome abnormalities are associated with the malignant progression of cancer. Transcription factor EB (TFEB) is the master transcriptional regulator of the autophagy‒lysosome machinery, and its abnormal activity is associated with autophagy-lysosome dysfunction. Polyphyllin II (PPII), an active steroidal saponin isolated from the rhizomes of Paris polyphylla, has been demonstrated to have antitumor activity.

PURPOSE

Here, we explored the antitumor activity of PPII in breast cancer (BC) and further clarified its mechanism.

METHODS

Autophagosome was detected by transmission electron microscopy, an autophagy indicator system, and western blot. The effect of PPII on lysosomal activity was evaluated by flow cytometry, a lysosomal cathepsin activity assay, and acridine orange staining. The effect of PPII on the signaling pathway was evaluated by Western blot, gene expression measurement, gene alterations. The binding of PPII and MOB1 was examined through a drug affinity responsive target stability assay. The pharmacokinetic parameters of PPII were evaluated in Sprague-Dawley rats.

RESULTS

PPII exhibits therapeutic potential in BC by inducing the accumulation of autophagosome. PPII promotes the cytoplasmic retention of YAP/TFEB, which is responsible for the accumulation of autophagosome in BC. PPII activates Hippo signaling to promote cytoplasmic retention of YAP. PPII activates Hippo signaling by accelerating acetylation of MOB1 through a direct binding interaction.

CONCLUSION

Taken together, these results confirm that acetylation of MOB1 mediates PPII-induced autophagosome accumulation in BC by promoting cytoplasmic retention of the YAP/TFEB coactivator complex. PPII is expected to be a drug candidate for the treatment of BC based on lysosomal biosynthesis.

The research progress of crosstalk mechanism of autophagy and apoptosis in diabetic vascular endothelial injury

In recent years, the widespread prevalence of diabetes has become a major killer that threatens the health of people worldwide. Of particular concern is hyperglycemia-induced vascular endothelial injury, which is one of the factors that aggravate diabetic vascular disease. During the process of diabetic vascular endothelial injury, apoptosis is an important pathological manifestation and autophagy is a key regulatory mechanism. Autophagy and apoptosis interact with each other. Hence, the crosstalk mechanism between the two processes is an important means of regulating diabetic vascular endothelial injury. This article reviews the research progress in apoptosis in the context of diabetic vascular endothelial injury and discusses the crosstalk mechanism of autophagy and apoptosis and its role in this injury. The purpose is to guide the prevention and treatment of diabetic vascular endothelial injury in the future.

Physiological and pathological characteristics of vascular endothelial injury in diabetes and the regulatory mechanism of autophagy

Vascular endothelial injury in diabetes mellitus (DM) is the major cause of vascular disease, which is closely related to the occurrence and development of a series of vascular complications and has a serious negative impact on a patient's health and quality of life. The primary function of normal vascular endothelium is to function as a barrier function. However, in the presence of DM, glucose and lipid metabolism disorders, insulin resistance, inflammatory reactions, oxidative stress, and other factors cause vascular endothelial injury, leading to vascular endothelial lesions from morphology to function. Recently, numerous studies have found that autophagy plays a vital role in regulating the progression of vascular endothelial injury. Therefore, this article compares the morphology and function of normal and diabetic vascular endothelium and focuses on the current regulatory mechanisms and the important role of autophagy in diabetic vascular endothelial injury caused by different signal pathways. We aim to provide some references for future research on the mechanism of vascular endothelial injury in DM, investigate autophagy's protective or injurious effect, and study potential drugs using autophagy as a target.