Local inhibition of glaucomatous mitochondrial dysfunction using an engineered annular sector microneedle

Mitochondrial dysfunction plays a critical role in glaucomatous trabecular meshwork (TM) degeneration, whereas increasing intracellular nicotinamide adenine dinucleotide (NAD⁺) levels can restore mitochondrial homeostasis, offering therapeutic benefits for glaucoma. We propose that intracellular NAD⁺ can be boosted by promoting NAD⁺ biosynthesis through the co-delivery of nicotinamide (NAM), an NAD⁺ precursor, and the gene encoding nicotinamide mononucleotide adenylyltransferase 1 (Nmnat1), the rate-limiting enzyme for NAD⁺ biosynthesis that consumes NAM. To achieve high gene transfection efficiency, the Nmnat1 gene was encapsulated in a multifunctional lipid nanoparticle (Nmnat1-LNPs). The combination of Nmnat1-LNPs and NAM synergistically reversed mitochondrial dysfunction in primary human trabecular meshwork cells (HTMCs) model. We then developed a new annular sector-shaped microneedle patch (AS-MNs), enabling localized delivery of Nmnat1-LNPs and NAM to the TM. Following application, Nmnat1-LNPs and NAM dual-loaded AS-MNs (Dual@AS-MNs) significantly enhanced the bioavailability of both the Nmnat1 gene and NAM in the TM tissue, leading to a marked reduction in intraocular pressure and alleviation of TM fibrosis in a dexamethasone-induced mice model of glaucoma, highlighting its therapeutic potential. This study presents the first development of an annular sector-shaped microneedle patch as a targeted TM drug delivery platform, and offers a promising new combinatorial strategy for glaucoma treatment.