June 2017
Volume 58, Issue 8
Open Access
ARVO Annual Meeting Abstract  |   June 2017
Neuroprotectin D1 (NPD1) downregulates amyloid beta (Aβ42) oligomer-induced senescence in human retinal pigment epithelial (RPE) cells
Author Affiliations & Notes
  • Khanh Do
    LSU-Health Science Center, New Orleans, Louisiana, United States
  • Nicolas Guillermo Bazan
    LSU-Health Science Center, New Orleans, Louisiana, United States
  • Footnotes
    Commercial Relationships   Khanh Do, None; Nicolas Bazan, None
  • Footnotes
    Support  NIH, EY005121 and GM103340 (NGB), the EENT Foundation (NGB), Vietnam Education Foundation (KD) and Schlumberger Foundation Faculty for the Future (KD)
Investigative Ophthalmology & Visual Science June 2017, Vol.58, 5368. doi:
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    • Get Citation

      Khanh Do, Nicolas Guillermo Bazan; Neuroprotectin D1 (NPD1) downregulates amyloid beta (Aβ42) oligomer-induced senescence in human retinal pigment epithelial (RPE) cells. Invest. Ophthalmol. Vis. Sci. 2017;58(8):5368.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Purpose : Aβ42, one of the end products of the amyloidogenic pathway, is a component of drusen in age-related macular degeneration (AMD) and of senile plaques of Alzheimer’s disease (AD) (Bazan NG.Future Neurol. 2016; 11:99). In our previous studies NPD1 was shifts the amyloid precursor protein (APP) processing from toxic amyloidogenic to non-amyloidogenic (Zhao Y, et al. PLoS One. 2011). Molecular mechanisms of senescence, and how to regulate them, in the RPE are key for the discovery of disease modifying therapies in AMD (Liu, et al. Int. J. Mol. Med. 2015). Here we aim to determine if Aβ42-oligomers (O-Aβ42) on hRPE cells or NPD1 are able to prevent Aβ42-induced senescence in RPE cells. Thus we explored mainly the p16INK4a, that is induced by cellular stress, acts as a late response to telomeric DNA damage and expression increases with age.

Methods : The primary hRPE cells were incubated with 1 μM or 10 μM of O-Aβ42. After 4 and 7 days, cells were fixed and subjected to apoptosis assay (TUNEL and Caspase-3 staining) and senescence assay (β-Galactosidase and p16INK4a staining). The TNF-α and H2O2 induced-oxidative stress (OS) was used as a positive control of apoptosis. Then we examined the ability of NPD1 (200 nM) to rescue senescent RPE. The abundance of p16INK4a, and p21Waf1/Cip1 were evaluated by Western blot (WB) and the transcriptional level of senescence-associated inflammation genes (IL-1, IL-6, IL-8) was analyzed by RT-PCR.

Results : NPD1 shifts the APP processing away from amyloidogenic pathway towards sAPP-α. For chronic uncompensated OS (ARPE-19, H2O2 300µM, for hRPE cells, H2O2 500µM, treated continuously for 5 days), NPD1 rescues the RPE cells. The formation of Aβ42 oligomers was confirmed by WB. In hRPE cells, O-Aβ42 induced senescence as evidenced by a higher abundance of β-Galactosidase and p16INK4a, while apoptosis was unaffected as reflected by low expression of TUNEL and Caspase-3-positive cells. The WB and RT-PCR results showed that NPD1 decreased the level of both senescent markers and senescence-associated inflammation genes expression.

Conclusions : NPD1 protects hRPE cells from uncompensated oxidative stress (acute or chronic) and shifts the APP processing away from the amyloidogenic pathway. NPD1 also potently protects hRPE cells from O-Aβ42 induced senescence by down regulating senescent markers and senescence-associated inflammation genes.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.

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