1. Academic Validation
  2. Phosphodiesterase 5 inhibitor mirodenafil ameliorates Alzheimer-like pathology and symptoms by multimodal actions

Phosphodiesterase 5 inhibitor mirodenafil ameliorates Alzheimer-like pathology and symptoms by multimodal actions

  • Alzheimers Res Ther. 2022 Jul 8;14(1):92. doi: 10.1186/s13195-022-01034-3.
Byung Woo Kang  # 1 Fred Kim  # 1 Joon-Yong Cho 2 SangYun Kim 3 Jinseol Rhee 4 Jai Jun Choung 5
Affiliations

Affiliations

  • 1 Pharmacology Team, AriBio Co., Ltd, 56 Dongpangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13535, Republic of Korea.
  • 2 Department of Exercise Biochemistry, Korea National Sport University, Seoul, 05541, Republic of Korea.
  • 3 Department of Neurology, Seoul National University College of Medicine & Seoul National University Bundang Hospital, 82 Gumi-ro 173-beongil, Bundang-gu, Seongnam-si, Gyeonggi-do, 13620, Republic of Korea.
  • 4 Pharmacology Team, AriBio Co., Ltd, 56 Dongpangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13535, Republic of Korea. [email protected].
  • 5 Pharmacology Team, AriBio Co., Ltd, 56 Dongpangyo-ro, Bundang-gu, Seongnam-si, Gyeonggi-do, 13535, Republic of Korea. [email protected].
  • # Contributed equally.
Abstract

Background: Alzheimer's disease (AD) pathology is associated with complex interactions among multiple factors, involving an intertwined network of various signaling pathways. The polypharmacological approach is an emerging therapeutic strategy that has been proposed to overcome the multifactorial nature of AD by targeting multiple pathophysiological factors including Amyloid-β (Aβ) and phosphorylated tau. We evaluated a blood-brain barrier penetrating phosphodiesterase 5 (PDE5) inhibitor, mirodenafil (5-ethyl-2-7-n-propyl-3,5-dihydrro-4H-pyrrolo[3,2-d]pyrimidin-4-one), for its therapeutic effects on AD with polypharmacological properties.

Methods: To evaluate the potential of mirodenafil as a disease-modifying AD agent, mirodenafil was administered to test its effects on the cognitive behaviors of the APP-C105 AD mouse model using the Morris water maze and passive avoidance tests. To investigate the mechanisms of action that underlie the beneficial disease-modifying effects of mirodenafil, human neuroblastoma SH-SY5Y cells and mouse hippocampal HT-22 cells were used to show mirodenafil-induced alterations associated with the cyclic guanosine monophosphate (cGMP)/cGMP-dependent protein kinase (PKG)/cAMP-responsive element-binding protein (CREB) pathway, apoptotic cell death, tau phosphorylation, amyloidogenesis, the autophagy-lysosome pathway, Glucocorticoid Receptor (GR) transcriptional activity, and the Wnt/β-catenin signaling.

Results: Here, mirodenafil is demonstrated to improve cognitive behavior in the APP-C105 mouse model. Mirodenafil not only reduced the Aβ and phosphorylated tau burdens in vivo, but also ameliorated AD pathology induced by Aβ through the modulation of the cGMP/PKG/CREB signaling pathway, glycogen synthase kinase 3β (GSK-3β) activity, GR transcriptional activity, and the Wnt/β-catenin signaling in neuronal cells. Interestingly, homodimerization and nuclear localization of GR were inhibited by mirodenafil, but not by other PDE5 inhibitors. In addition, only mirodenafil reduced the expression levels of the Wnt antagonist Dickkopf-1 (Dkk-1), thus activating the Wnt/β-catenin signaling.

Conclusions: These findings strongly suggest that the PDE5 Inhibitor mirodenafil shows promise as a potential polypharmacological drug candidate for AD treatment, acting on multiple key signaling pathways involved in amyloid deposition, phosphorylated tau burden, the cGMP/PKG/CREB pathway, GSK-3β kinase activity, GR signaling, and the Wnt/β-catenin signaling. Mirodenafil administration to the APP-C105 AD mouse model also improved cognitive behavior, demonstrating the potential of mirodenafil as a polypharmacological AD therapeutic agent.

Keywords

Alzheimer’s disease; Amyloid-β; Apoptosis; Autophagy; Dickkopf-1; Glucocorticoid receptor; Mirodenafil; Phosphodiesterase 5; Wnt/β-catenin; tau.

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