Chronotherapeutic neuroprotective effect of verapamil against lipopolysaccharide-induced neuroinflammation in mice through modulation of calcium-dependent genes

Abstract

Background Neuroinflammation is a major mechanism in neurodegenerative diseases such as Alzheimer’s disease (AD), which is a major healthcare problem. Notwithstanding of ample researches figured out possible molecular mechanisms underlying the pathophysiology of AD, there is no definitive therapeutics that aid in neuroprotection. Therefore, searching for new agents and potential targets is a critical demand. We aimed to investigate the neuroprotective effect of verapamil (VRP) against lipopolysaccharide (LPS)-induced neuroinflammation in mice and whether the time of VRP administration could affect its efficacy. Methods Forty male albino mice were used and were divided into normal control, LPS only, morning VRP, and evening VRP. Y-maze and pole climbing test were performed as behavioral tests. Hematoxylin and eosin together with Bielschowsky silver staining were done to visualize neuroinflammation and phosphorylated tau protein (pTAU); respectively. Additionally, the state of mitochondria, the levels of microglia-activation markers, inflammatory cytokines, intracellular Ca2+, pTAU, and Ca2+-dependent genes involving Ca2+/ calmodulin dependent kinase II (CAMKII) isoforms, protein kinase A (PKA), cAMP response element-binding protein (CREB), and brain-derived neurotrophic factor (BDNF), with the level of VRP in the brain tissue were measured. Results LPS successfully induced neuroinflammation and hyperphosphorylation of tau protein, which was indicated by elevated levels of microglia markers, inflammatory cytokines, and intracellular Ca2+ with compromised mitochondria and downregulated CAMKII isoforms, PKA, CREB and BDNF. Pretreatment with VRP showed significant enhancement in the architecture of the brain and in the behavioral tests as indicated by the measured parameters. Moreover, morning VRP exhibited better neuroprotective profile compared to the evening therapy. Conclusions VRP highlighted a multilevel of neuroprotection through anti-inflammatory activity, Ca2+ blockage, and regulation of Ca2+-dependent genes. Furthermore, chronotherapy of VRP administration should be consider to achieve best therapeutic efficacy. Graphical Abstract

Circadian Rhythms of the Blood-Brain Barrier and Drug Delivery

“…Many anti-epileptic drugs are P-gp and BCRP transporter substrates 162 and circadian differences in transporter activity may underlie alterations in the effectiveness of the anti-epileptic drugs. Studies of quinidine, 63 verapamil, 163 and other P-gp substrates 68 (described in detail above) have shown higher levels or improved neuroprotective functions at different circadian times. Mosalam et al 163 also examined the efficacy of verapamil, in reducing lipopolysaccharide-induced neuroinflammation when given at 9 am and 5 pm in mice and found greater brain entry of verapamil and neuroprotection at 9 am .…”

“…Many anti-epileptic drugs are P-gp and BCRP transporter substrates 162 and circadian differences in transporter activity may underlie alterations in the effectiveness of the anti-epileptic drugs. Studies of quinidine, 63 verapamil, 163 and other P-gp substrates 68 (described in detail above) have shown higher levels or improved…”

“…Studies of quinidine, 63 verapamil, 163 and other P-gp substrates 68 (described in detail above) have shown higher levels or improved neuroprotective functions at different circadian times. Mosalam et al 163 also examined the efficacy of verapamil, in reducing lipopolysaccharide-induced neuroinflammation when given at 9 am and 5 pm in mice and found greater brain entry of verapamil and neuroprotection at 9 am .…”

The Potential Neuroprotective Effect of Thymoquinone on Scopolamine-Induced In Vivo Alzheimer’s Disease-like Condition: Mechanistic Insights

“…Mitochondrial impairment is widely recognized as a significant contributor to the pathogenesis of AD [ 53 ]. A growing body of evidence suggested that dysregulation of MMP may occur due to oxidative stress and neuroinflammation [ 53 , 54 ].…”

“…Mitochondrial impairment is widely recognized as a significant contributor to the pathogenesis of AD [ 53 ]. A growing body of evidence suggested that dysregulation of MMP may occur due to oxidative stress and neuroinflammation [ 53 , 54 ]. Furthermore, the process of excessive phosphorylation of tau protein has been observed to impede mitochondrial transport at the synapse, causing severe oxidative stress [ 55 ].…”