NRF2-activating agents exert antioxidant effects by enhancing endogenous H₂S formation

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Anacak G. Y., Özbek E. N., Yeşilyurt Dirican Z. E., Arıoğlu İnan E.

NRF2 bench to bedside , İstanbul, Türkiye, 9 - 10 Ekim 2025, (Yayınlanmadı)

  • Yayın Türü: Bildiri / Yayınlanmadı
  • Basıldığı Şehir: İstanbul
  • Basıldığı Ülke: Türkiye
  • Acıbadem Mehmet Ali Aydınlar Üniversitesi Adresli: Evet

Özet

NRF2-activating agents exert antioxidant effects by enhancing endogenous H₂S formation.

 

Emine Nur Ozbek1, Zeynep Elif Yesilyurt Dirican2, Ilayda Okumus4,, Medine Makal1, Yiğitcan Şar4  Ebru Arioglu Inan3, Gunay Yetik-Anacak4*

1   Department of Pharmacology, Faculty of Pharmacy, Ege University, Izmir, Türkiye.

2   Department of Pharmacology, Faculty of Pharmacy, Gazi University, Ankara, Türkiye.

3   Department of Pharmacology, Faculty of Pharmacy, Ankara University, Ankara, Türkiye.

4   Department of Pharmacology, Faculty of Pharmacy, Acibadem Mehmet Ali Aydinlar University, Istanbul, Türkiye.

*  Correspondence: Gunay.Anacak@acibadem.edu.tr

 

Background: Nuclear factor erythroid 2–related factor 2 (NRF2) is a master regulator of cellular antioxidant defense. Hydrogen sulfide (H₂S) is an endogenously produced gaseous neurotransmitter, activates NRF2 by persulfidating critical cysteine residues of Keap1, thereby preventing NRF2 degradation and promoting its nuclear translocation to induce antioxidant gene expression [1]. H₂S donors exhibit neuro/cardioprotection in oxidative stress-related disorders in preclinical studies; but, their clinical use is limited by unpleasant odor and short half-lives [2,3]. However, endogenous H₂S stimulators with antioxidant properties have advantages as a promising therapeutic approach over H2S donors regarding safety and patient compliance. Empagliflozin (EMPA), a sodium-glucose cotransporter-2 (SGLT2) inhibitor, widely used in diabetes mellitus (DM) and sildenafil, a phosphodiesterase-5 inhibitor, both have antioxidant and neuroprotective effects and have been reported to activate the NRF2 signaling [4,5]. This study aimed to investigate whether endogenous H₂S production contributes to the neuroprotective and antioxidant effects of EMPA and sildenafil.

Methods: Ex vivo experiments in mouse brain and heart tissues performed to assess the effects of EMPA on H₂S levels and reactive oxygen species (ROS) formation under basal and Pyrogallol-induced oxidative stress conditions. Rats were divided into four groups: nondiabetic, EMPA-treated nondiabetic, streptozotocin (STZ)-induced diabetic, and EMPA-treated STZ-diabetic. Brain H₂S and ROS levels were measured by methylene blue and chemiluminescence assays, respectively. The role of H₂S was further confirmed using the synthesis inhibitor aminooxyacetic acid (AOAA).

Results: Ex vivo EMPA and Sildenafil treatment significantly increased endogenous H2S formation in both healthy and pyrogallol-induced oxidative stress and reduced ROS formation in mouse brain and heart, respectively; these effects were significantly reversed by the H2S synthesis inhibitor, aminooxyacetic acid (AOAA)( p<0.001, n=6). Oral EMPA administration significantly elevated brain H₂S levels in both nondiabetic and diabetic rats (p<0.001, p<0.05, n=6, respectively) and reduced ROS formation (p<0.01, n=6). These effects were inhibited by AOAA.

Conclusions: Our findings suggest that NRF2-activating agents exert neuroprotection and cardioprotection against oxidative stress through the H₂S pathway. The NRF2–H₂S signaling axis highlights a novel mechanism with therapeutic potential in oxidative stress–related disorders.

Acknowledgement: We thank the Turkish Scientific Research Council (TUBITAK) for the support (grant numbers: 119S769, 1919B012301772 and 1919B012320814).

 

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