Dynamin-like Protein 1 (DNML1) as a Molecular Target for Antibody-Based Immunotherapy to Treat Glaucoma

Abstract

Slow and progressive loss of retinal ganglion cells (RGCs) is the main characteristic of glaucoma, the second leading cause of blindness worldwide. Previous studies have shown that impaired mitochondrial dynamics could facilitate retinal neurodegeneration. Mitochondrial dynamics are regulated directly (fission) or more indirectly (fusion) by dynamin-like protein 1 (DNML1). Therefore, DNM1L might be a promising target for an antibody-based approach to treat glaucoma. The consequences of targeting endogenous DNM1L by antibodies in a glaucoma animal model have not been investigated yet. Here, we show that the intravitreal application of an anti-DNM1L antibody showed protective effects regarding the survival of RGCs and their axons in the retinal nerve fiber layer (RNFL). Antibody treatment also improved retinal functionality, as observed by electroretinography (Ganzfeld ERG). Western blot analysis revealed altered DNM1L phosphorylation and altered expression of proteins related to apoptosis suggesting a decreased apoptosis rate. Mass spectrometry analysis revealed 28 up-regulated and 21 down-regulated proteins (p < 0.05) in both experimental groups. Protein pathway analysis showed that many proteins interacted directly with the target protein DNM1L and could be classified into three main protein clusters: Vesicle traffic-associated (NSF, SNCA, ARF1), mitochondrion-associated (HSP9A, SLC25A5/ANT2, GLUD1) and cytoskeleton-associated (MAP1A) signaling pathway. Our results demonstrate that DNM1L is a promising target for an antibody-based approach to glaucoma therapy.

Posttranslational modifications of proteins in diseased retina

“…By assessing proteomic changes in human glaucomatous retina samples, Funke et al demonstrated that the levels of a plethora of proteins are altered in glaucoma ( Funke et al, 2016 ). Further, while studies have been published on large-scale proteomics studies pertaining to protein expression at the onset of central nervous system (CNS) neuron injury ( Tonner et al, 2022 ), the PTMome of RGCs in neurodegenerative diseases is largely unknown. Liu et al and Lukas et al each assessed phosphoproteomic changes in mouse total retina lysate following optic nerve injury ( Lukas et al, 2009 ; Liu et al, 2020 ).…”

The Role of Mitophagy in Glaucomatous Neurodegeneration

“…P62-mediated mitophagy inducer (PMI) is another promising neuroprotective agent that inhibits KEAP1 and activates NF-E2-related factor 2 (NRF2), leading to the expression of antioxidant genes, including sequestosome 1 (p62/SQSTM1), and enhanced mitophagy [239]. DRP1 may also serve as an auspicious target for a potential antibody-based therapy for glaucoma, since intravitreal injection of an anti-DRP1 antibody in an animal glaucoma model protected RGCs, decreased apoptosis as shown using western blot analysis, and improved retinal functionality as observed using electroretinography [240].…”