Mushroom spines form strong synaptic contacts and are essential for memory storage. We have previously demonstrated that neuronal store-operated calcium entry (nSOC) in hippocampal neurons is regulated by STIM2 protein. This pathway plays a key role in stability of mushroom spines and is compromised in different mice models of Alzheimer’s disease (AD). Actin was thought to be the sole cytoskeleton compartment presented in dendritic spines, however, recent studies demonstrated that dynamic microtubules with EB3 capped plus-ends transiently enter spines. We showed that STIM2 forms an endoplasmic reticulum (ER) Ca²⁺ -dependent complex with EB3 via Ser-x-Ile-Pro aminoacid motif and that disruption of STIM2-EB3 interaction resulted in loss of mushroom spines in hippocampal neurons. Overexpression of EB3 causes increase of mushroom spines fraction and is able to restore their deficiency in hippocampal neurons obtained from PS1-M146V-KI AD mouse model. STIM2 overexpression failed to restore mushroom dendritic spines after EB3 knockdown, while in contrast EB3 overexpression rescued loss of mushroom spines resulting from STIM2 depletion. We propose that EB3 is involved in regulation of dendritic spines morphology, in part due to its association with STIM2, and that modulation of EB3 expression is a potential way to overcome synaptic loss during AD.

Alzheimer9s disease is the neurodegenerative disorder that is a major cause of dementia in the elderly. There is no cure against AD. We have recently discovered novel TRPC6-mediated intracellular signaling pathway that regulates stability of dendritic spines and plays a role in memory formation. We have previously shown that TRPC6 agonists exert beneficial effects in models of AD and may serve as lead compounds for development of AD therapeutic agents. In the current study, we used Integrity database to search for additional TRPC6 agonists. We have selected four compounds to study them as potential neuroprotective agents. We applied bioinformatical analyses to test basic pharmacological properties of selected compounds. We performed in vitro screening of these compounds to validate their ability to protect mushroom spines from amyloid toxicity and determined that two of these compounds exert neuroprotective effects in the nanomolar concentration range. We have chosen one of these compounds (piperazine, PPZ) for further testing. In agreement with previously published data, we have shown that PPZ activates TRPC6 channels. We demonstrated that neuroprotective mechanism of investigated PPZ is based on activation of neuronal store-operated calcium entry (nSOCE) in spines. We have shown that PPZ restores long-term potentiation (LTP) induction in 6 months old 5xFAD mouse hippocampal slices. Obtained results suggest that PPZ and its derivatives are potential lead molecules for development of AD therapeutic agents.

Despite decades of research and effort, there is still no effective disease-modifying treatment for Alzheimer’s Disease (AD). Most of the recent AD clinical trials were targeting amyloid pathway, but all these trials failed. Although amyloid pathology is a hallmark and defining feature of AD, targeting the amyloid pathway has been very challenging due to low efficacy and serious side effects. Alternative approaches or mechanisms for our understanding of the major cause of memory loss in AD need to be considered as potential therapeutic targets. Increasing studies suggest that Ca2+ dysregulation in AD plays an important role in AD pathology and is associated with other AD abnormalities, such as excessive inflammation, increased ROS, impaired autophagy, neurodegeneration, synapse, and cognitive dysfunction. Ca2+ dysregulation in cytosolic space, Endoplasmic Reticulum (ER) and mitochondria have been reported in the context of various AD models. Drugs or strategies, to correct the Ca2+ dysregulation in AD, have been demonstrated to be promising as an approach for the treatment of AD in preclinical models. This review will discuss the mechanisms of Ca2+ dysregulation in AD and associated pathology and discuss potential approaches or strategies to develop novel drugs for the treatment of AD by targeting Ca2+ dysregulation.

Alzheimer’s disease and cerebral ischemia are among the many causative neurodegenerative diseases that lead to disabilities in the middle-aged and elderly population. There are no effective disease-preventing therapies for these pathologies. Recent in vitro and in vivo studies have revealed the TRPC6 channel to be a promising molecular target for the development of neuroprotective agents. TRPC6 channel is a non-selective cation plasma membrane channel that is permeable to Ca²⁺. Its Ca²⁺-dependent pharmacological effect is associated with the stabilization and protection of excitatory synapses. Downregulation as well as upregulation of TRPC6 channel functions have been observed in Alzheimer’s disease and brain ischemia models. Thus, in order to protect neurons from Alzheimer’s disease and cerebral ischemia, proper TRPC6 channels modulators have to be used. TRPC6 channels modulators are an emerging research field. New chemical structures modulating the activity of TRPC6 channels are being currently discovered. The recent publication of the cryo-EM structure of TRPC6 channels should speed up the discovery process even more. This review summarizes the currently available information about potential drug candidates that may be used as basic structures to develop selective, highly potent TRPC6 channel modulators to treat neurodegenerative disorders, such as Alzheimer’s disease and cerebral ischemia.

The Morris Water Maze (MWM) behavioral test is a universal method for testing cognitive functions in experimental rodents, and it is especially effective in detecting deviations in memory functions and learning, which makes it indispensable in a study of aging, stroke, neurodegenerative diseases, effects of therapeutic drugs, and so on. However, this test can be a far more informative tool for analyzing the behavior of experimental animals than it seems at first glance. The formation and consolidation of memory, as well as learning, are quite complex processes that mainly involve the hippocampus but, in addition, many other brain areas. The numerous MWM protocols are so sensitive to changes in functioning of different, not only hippocampal, brain areas that they can be used as an “indicator” of normal cognitive function. Thus, MWM modifications involve different mechanisms of navigation, learning and memory, and the results of these tests, as well as their correct interpretation, can give a lot more information about the behavior of tested animals. Here, we survey most popular methods for conducting the MWM procedure and discuss those informative parameters that can help analyze the results of this test.