Receptor interacting protein 3 kinase, not 1 kinase, through MLKL-mediated necroptosis is involved in UVA-induced corneal endothelium cell death

Zhen Yu,Victor S M C Correa,Xiaohong Chen,Toshio Narimatsu,Dimitrios Ntentakis,Kenji Ishihara,Yanyun Chen,Yasuhiro Iesato,Nikolaos E Efstathiou,Demetrios G Vavvas

doi:10.1038/s41420-021-00757-w

Zhen Yu, Victor S M C Correa + Show 8 more

Open Access

https://doi.org/10.1038/s41420-021-00757-w

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Abstract

Ultraviolet (UV) is one of the most energetic radiations in the solar spectrum that can result in various tissue injury disorders. Previous studies demonstrated that UVA, which represents 95% of incident photovoltaic radiation, induces corneal endothelial cells (CECs) death. Programmed cell death (PCD) has been implicated in numerous ophthalmologic diseases. Here, we investigated receptor-interacting protein 3 kinase (RIPK3), a key signaling molecule of PCD, in UVA-induced injury using a short-term corneal endothelium (CE) culture model. UVA irradiation activated RIPK3 and mediated necroptosis both in mouse CE and primary human CECs (pHCECs). UVA irradiation was associated with upregulation of key necroptotic molecules (DAI, TRIF, and MLKL) that lie downstream of RIPK3. Moreover, RIPK3 inhibition or silencing in primary corneal endothelial cells suppresses UVA-induced cell death, along with downregulation of MLKL in pHCECs. In addition, genetic inhibition or knockout of RIPK3 in mice (RIPK3K51A and RIPK3−/− mice) similarly attenuates cell death and the levels of necroptosis in ex vivo UVA irradiation experiments. In conclusion, these results identify RIPK3, not RIPK1, as a critical regulator of UVA-induced cell death in CE and indicate its potential as a future protective target.

Highlights

Ultraviolet light (UV) is one of the most energetic radiations of the solar spectrum, divided into three regions according to wavelength: UVA (320–400 nm), UVB (290–320 nm), and UVC (190–290 nm)
RIPK3 expression increases after high-dose UVA To evaluate how UVA affects cell death, we set up a UVA injury ex vivo model through the short-term culture of mice corneal endothelium (CE)
RIPK1/3 are universally expressed and widely known for their with significantly increased expression of RIPK3 detected by role in promoting cell death, especially necroptosis [30, 31]

Summary

INTRODUCTION

Ultraviolet light (UV) is one of the most energetic radiations of the solar spectrum, divided into three regions according to wavelength: UVA (320–400 nm), UVB (290–320 nm), and UVC (190–290 nm). Programmed cell death (PCD) includes CASPASE mediated cell death process known as apoptosis and RIPK regulated cell death known as programmed necrosis or necroptosis [9–11]. Both of these process have been implicated in multiple posterior ophthalmologic diseases such as neovascular age-related macular degeneration (AMD), and retinitis pigmentosa (RP) [12–14], only apoptosis have been implicated in anterior ophthalmic diseases such as Fuchs endothelial corneal dystrophy (FECD) [15, 16]. There are no studies investigating the role of RIPK regulated necrosis after UVA injury In this present study, with the help of genetically engineered mice and inhibitors of RIPK1, RIPK3, and CASPASEs, we explored a critical necroptotic function of RIPK3 in UVA-induced CE injury in vitro and ex vivo

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