The role of NAD+ metabolism in macrophages in age-related macular degeneration

Advances in the Synthesis and Physiological Metabolic Regulation of Nicotinamide Mononucleotide

Nicotinamide mononucleotide (NMN), the direct precursor of nicotinamide adenine dinucleotide (NAD+), is involved in the regulation of many physiological and metabolic reactions in the body. NMN can indirectly affect cellular metabolic pathways, DNA repair, and senescence, while also being essential for maintaining tissues and dynamic metabolic equilibria, promoting healthy aging. Therefore, NMN has found many applications in the food, pharmaceutical, and cosmetics industries. At present, NMN synthesis strategies mainly include chemical synthesis and biosynthesis. Despite its potential benefits, the commercial production of NMN by organic chemistry approaches faces environmental and safety problems. With the rapid development of synthetic biology, it has become possible to construct microbial cell factories to produce NMN in a cost-effective way. In this review, we summarize the chemical and biosynthetic strategies of NMN, offering an overview of the recent research progress on host selection, chassis cell optimization, mining of key enzymes, metabolic engineering, and adaptive fermentation strategies. In addition, we also review the advances in the role of NMN in aging, metabolic diseases, and neural function. This review provides comprehensive technical guidance for the efficient biosynthesis of NMN as well as a theoretical basis for its application in the fields of food, medicine, and cosmetics.

Role of immune inflammation regulated by macrophage in the pathogenesis of age-related macular degeneration

Age-related macular degeneration (AMD) can lead to irreversible impairment of visual function, and the number of patients with AMD has been increasing globally. The immunoinflammatory theory is an important pathogenic mechanism of AMD, with macrophages serving as the primary inflammatory infiltrating cells in AMD lesions. Its powerful immunoinflammatory regulatory function has attracted considerable attention. Herein, we provide an overview of the involvement of macrophage-regulated immunoinflammation in different stages of AMD. Additionally, we summarize novel therapeutic approaches for AMD, focusing on targeting macrophages, such as macrophage/microglia modulators, reduction of macrophage aggregation in the subretinal space, modulation of macrophage effector function, macrophage phenotypic alterations, and novel biomimetic nanocomposites development based on macrophage-associated functional properties. We aimed to provide a basis and reference for the further exploration of AMD pathogenesis, developmental influences, and new therapeutic approaches.

Roles and mechanisms of long non-coding RNAs in age-related macular degeneration

Worldwide, age-related macular degeneration (AMD) is a multifactorial progressive fundus disorder that can cause vision impairment and severe central blindness in older adults. Currently, there are no approved prevention or treatment strategies for non-exudative AMD. While targeting VEGF is the main therapeutic approach to delay the degeneration process in exudative AMD, a significant number of patients show insensitivity or ineffectiveness to anti-VEGF therapy. Despite years of research, the exact mechanism underlying drusen formation and macular atrophy in AMD remains unknown. In the pathogenesis of AMD, lncRNAs play crucial roles, as discussed in this paper. This review focuses on the function of dysregulated lncRNAs and the mechanisms by which specific molecules target these lncRNAs in AMD. The analysis reveals that lncRNAs primarily regulate the progression of AMD by mediating apoptosis, epithelial-mesenchymal transition (EMT), dedifferentiation, and oxidative stress in choroidal vascular endothelial cells, retinal pigment epithelium (RPE) cells, and photoreceptors. Consequently, the regulation of apoptosis, dedifferentiation, EMT, and other processes by lncRNAs has emerged as a crucial focus in AMD research.These findings contribute to our understanding of the role of lncRNAs in AMD and their potential as valuable biomarkers. Furthermore, they highlight the need for further basic and clinical studies to explore the value of lncRNAs as biomarkers and potential therapeutic targets for AMD.