Modulating Effects of Vitamin K2 on Oxidative Stress Induced Organelle Damage in Alzheimer’s Disease

Abstract Background Current treatment strategies for AD are either involved in an improved amyloid‐beta precursor protein (APP) processing via inhibition and/or activation of enzymatic machinery. Whereas, others drug regimen includes the use of putative tau kinase inhibitors, microtubule stabilizers and tau immunotherapies. Moreover, therapies to combat oxidative stress are currently being devised because oxidative stress plays a major role innneurodegeneration. Interestingly, current studies are being focused on the screening of bioactive compounds for their effect on prevention of Aβ formation, oxidative stress reduction and targeting organelle dysfunction, which will potentiate the use of bioactive compounds to prevent AD in early stages. Vitamin K2 is one of the bioactive compounds which has gained importance for its role as an antioxidant. Method To understand the neuroprotective effect of vitamin K2 during metabolic complications, SH‐SY5Y cells were treated with streptozotocin for 24 h and menadione for 2 h in a dose dependent manner, followed by the post treatment of vitamin K2 for 5 h. Modulating effects of vitamin K2 on cell viability, Lactate Dehydrogenase release, reactive oxygen species (ROS), mitochondrial membrane potential, ER stress marker (CHOP), an indicator of unfolded protein response (UPR) p‐IRE1α, GSK 3α/β, total tau and Aβ 42 were studied. Result Vitamin K2 significantly reduced the neuronal cell death by inhibiting the cytotoxicity, ROS levels and helped in the retainment of mitochondrial membrane potential. Moreover, vitamin K2 significantly decreased the expression of CHOP protein along with the levels and the nuclear localization of p‐IRE1 α, thus showing its significant role in inhibiting chronic ER stress mediated UPR and eventually apoptosis. In addition, Vitamin K2 significantly downregulated the expression of GSK 3 α/β together with the levels of total tau protein, with petite effect on secreted Aβ 42 levels. Conclusion Vitamin K2 ameliorated mitochondrial damage, ER stress and tauopathy mediated neuronal cell death, highlighting its role as a novel antioxidative therapeutics targeting related cellular processes.