A small molecule Nec-1 directly induces amyloid clearance in the brains of aged APP/PS1 mice

Abstract

Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by the formation of toxic amyloid-β (Aβ) oligomers and plaques. Considering that Aβ misfolding and aggregation precedes the progressive development of cognitive impairment in AD, investigating a therapeutic means by clearance of pre-existing Aβ aggregates shows promise as a viable disease-modifying treatment. Here, we report that a small molecule, necrostatin-1 (Nec-1), reduces Aβ aggregates back to non-toxic monomers in vitro and in vivo. Intravenous administration of Nec-1 reduced the levels of Aβ plaques in the brains of aged APP/PS1 double transgenic mice. In addition, Nec-1 exhibited therapeutic effects against Aβ aggregates by inhibiting Aβ-induced brain cell death in neuronal and microglial cell lines. Nec-1 also showed anti-apoptotic and anti-necroptotic effects in the cortex of aged APP/PS1 mice by reducing levels of phosphorylated-RIPK3 and Bax and increasing the levels of Bcl-2. According to our data in vitro and in silico, the methyl group of the amine in the 2-thioxo-4-imidazolidinone is the key moiety of Nec-1 that directs its activity against aggregated Aβ. Given that the accumulation of Aβ aggregates is an important hallmark of AD, our studies provide strong evidence that Nec-1 may serve a key role in the development of AD treatment.

Necrostatin-1 Supplementation to Islet Tissue Culture Enhances the In-Vitro Development and Graft Function of Young Porcine Islets

“…While the majority of studies started Nec-1 treatment on the same day of an experiment, our novel findings support evidence from a previous study that delaying Nec-1 treatment for up to 72 h improved the survival rate of mice exposed to total body irradiation [19]. Another study has shown that Nec-1 supplementation started 5 days after the formation of Aβ aggregates in brain cells from monomeric Aβ42 peptides separated pre-formed Aβ aggregates and reduced the buildup of Aβ fibrils [20]. Our current data and previous works suggest that the timing of Nec-1 supplementation to tissue culture can notably affect the effectiveness of Nec-1.…”

“…As Nec-1 has been shown to be ineffective and even have toxic effects when its use is not optimized, a possible reason for this finding is that the prolonged culture of islets in media supplemented with Nec-1 immediately after isolation for 7 days could be damaging to islet cells, especially beta cells, which have been determined to be more vulnerable to insults than other types of islet cells [32][33][34][35]. This notion is further supported by previous studies, demonstrating that Nec-1 was primarily utilized for only 24 h and up to 5 days at most for in vitro culture [10,20,36]. In accordance with previous findings that the proliferation of mature delta cells is responsible for the formation of new delta cells, islets treated with Nec-1 on day 3 of tissue culture had a significant growth in both proliferating delta cells and delta-cell mass compared to untreated islets [37].…”

The effects of necrostatin‐1 on the in vitro development and function of young porcine islets over 14‐day prolonged tissue culture

“…As the majority of previous in vitro experiments has only utilized Nec‐1 for less than or equal to 24 hours, the failure of Nec‐1 to mitigate islet loss from day 7 to day 14 of tissue culture in the current study could be because the in vitro effects of Nec‐1 are short‐lived 23,24 . This notion is supported by a previous study, showing that Nec‐1 was only used up to the first 5 days at most to reduce the in vitro formation of Aβ fibrils from Aβ aggregates 25 . Moreover, novel growth factors, including oncostatin M, dexamethasone, and transforming growth factor beta‐1, have only been used for 3 to 6 days when added to young porcine islet tissue culture media 9 .…”

Neuroprotective Effects of Necrostatin-1 Against Oxidative Stress–Induced Cell Damage: an Involvement of Cathepsin D Inhibition

“…The cells were pre-treated with various concentrations of Nec-1 (1-40 μM) for 30 min followed by 24 h exposure to cell damaging factors (H 2 O 2 , 6-OHDA, Glu). The chosen concentrations of Nec-1 were based on literature search and included not active (< 1 μM) and RIP1-specific (> 3 μM) concentrations (Degterev et al 2008;Ito et al 2017;Yamanaka et al 2011;Yang et al 2017bYang et al , 2019. For comparison of the Nec-1 effects with other protectants, the antioxidant, Nacetylcysteine (NAC, 1 mM), and curcumin (Curc, 5 μM) were used.…”