Neutral sphingomyelinase inhibition promotes local and network degeneration in vitro and in vivo

Cell Communication and Signaling

Research

Nolan R. McGrady¹  David J. Calkins¹  Bhanu S. Kagitapalli¹  Marcio Ribeiro¹  Michael L. Risner²  Donald J. Zack³  Xitiz Chamling³ 

[1] Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave S., 37232, Nashville, TN, USA;Department of Ophthalmology and Visual Sciences, Vanderbilt Eye Institute, Vanderbilt University Medical Center, AA7103 MCN/VUIIS, 1161 21st Ave S., 37232, Nashville, TN, USA;Department of Foundational Medical Studies, Eye Research Center, Oakland University William Beaumont School of Medicine, 369 Dodge Hall, 118 Library Dr., 48309, Rochester, MI, USA;Department of Ophthalmology, Wilmer Eye Institute, Johns Hopkins University School of Medicine, 21287, Baltimore, MD, USA;

关键词: Human embryonic stem cells;    Retinal ganglion cells;    Extracellular vesicles;    Apoptosis;    Neutral sphingomyelinase;    GM1 ganglioside;    Ceramide;    Mitochondria;   

DOI  :  10.1186/s12964-023-01291-1

 received in 2023-06-08, accepted in 2023-08-22,  发布年份 2023

来源: Springer

【 摘 要 】

BackgroundCell-to-cell communication is vital for tissues to respond, adapt, and thrive in the prevailing milieu. Several mechanisms mediate intercellular signaling, including tunneling nanotubes, gap junctions, and extracellular vesicles (EV). Depending on local and systemic conditions, EVs may contain cargoes that promote survival, neuroprotection, or pathology. Our understanding of pathologic intercellular signaling has been bolstered by disease models using neurons derived from human pluripotent stems cells (hPSC).MethodsHere, we used hPSC-derived retinal ganglion cells (hRGC) and the mouse visual system to investigate the influence of modulating EV generation on intercellular trafficking and cell survival. We probed the impact of EV modulation on cell survival by decreasing the catabolism of sphingomyelin into ceramide through inhibition of neutral sphingomyelinase (nSMase), using GW4869. We assayed for cell survival in vitro by probing for annexin A5, phosphatidylserine, viable mitochondria, and mitochondrial reactive oxygen species. In vivo, we performed intraocular injections of GW4869 and measured RGC and superior colliculus neuron density and RGC anterograde axon transport.ResultsFollowing twenty-four hours of dosing hRGCs with GW4869, we found that inhibition of nSMase decreased ceramide and enhanced GM1 ganglioside accumulation. This inhibition also reduced the density of small EVs, increased the density of large EVs, and enriched the pro-apoptotic protein, annexin A5. Reducing nSMase activity increased hRGC apoptosis initiation due to enhanced density and uptake of apoptotic particles, as identified by the annexin A5 binding phospholipid, phosphatidylserine. We assayed intercellular trafficking of mitochondria by developing a coculture system of GW4869-treated and naïve hRGCs. In treated cells, inhibition of nSMase reduced the number of viable mitochondria, while driving mitochondrial reactive oxygen species not only in treated, but also in naive hRGCs added in coculture. In mice, 20 days following a single intravitreal injection of GW4869, we found a significant loss of RGCs and their axonal recipient neurons in the superior colliculus. This followed a more dramatic reduction in anterograde RGC axon transport to the colliculus.ConclusionOverall, our data suggest that perturbing the physiologic catabolism of sphingomyelin by inhibiting nSMase reorganizes plasma membrane associated sphingolipids, alters the profile of neuron-generated EVs, and promotes neurodegeneration in vitro and in vivo by shifting the balance of pro-survival versus -degenerative EVs.8WXtUmcgzqdrdTPfGd7tbXVideo Abstract

【 授权许可】

CC BY   
© The Author(s) 2023

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