Calcium regulation and Alzheimer's disease

Exploring nanoparticular platform in delivery of repurposed drug for Alzheimer's disease: current approaches and future perspectives

INTRODUCTION

Alzheimer's disease (AD) stands as significant challenge in realm of neurodegenerative disorder. It is characterized by gradual decline in cognitive function and memory loss. It has already expanded its prevalence to 55 million people worldwide and is expected to rise significantly. Unfortunately, there exists a limited therapeutic option that would mitigate its progression. Repurposing existing drugs and employing nanoparticle as delivery agent presents a potential solution to address the intricate pathology of AD.

AREAS COVERED

In this review, we delve into utilization of nanoparticular platforms to enhance the delivery of repurposed drugs for treatment of AD. Firstly, the review begins with the elucidation of intricate pathology underpinning AD, subsequently followed by rationale behind drug repurposing in AD. Covered are explorations of nanoparticle-based repurposing of drugs in AD, highlighting their clinical implication. Further, the associated challenges and probable future perspective are delineated.

EXPERT OPINION

The article has highlighted that extensive research has been carried out on the delivery of repurposed nanomedicines against AD. However, there is a need for advanced and long-term research including clinical trials required to shed light upon their safety and toxicity profile. Furthermore, their scalability in pharmaceutical set-up should also be validated.

Analyzing fuzzy boundary value problems: a study on the influence of mitochondria and ER fluxes on calcium ions in neuron cells

Cytosolic-free calcium ions play an important role in various physical and physiological processes. A vital component of neural signaling is the free calcium ion concentration often known as the second messenger. There are many parameters that effect the cytosolic free calcium concentration like buffer, voltage-gated ion channels, Endoplasmic reticulum, Mitochondria, etc. Mitochondria are small organelles located within the nervous system that are involved in processes within cells such as calcium homeostasis management, energy generation, response to stress, and cell demise pathways. In this work, a mathematical model with fuzzy boundary values has been developed to study the effect of Mitochondria and ER fluxes on free Calcium ions. The intended findings are displayed utilizing the physiological understanding that amyloid beta plaques and tangles of neurofibrillary fibers have been identified as the two main causes of AD. The key conclusion of the work is the investigation of [Formula: see text] for healthy cells and cells affected by Alzheimer's disease, which may aid in the study of such processes for computational scientists and medical practitioners. Also, it has been shown that when a unique solution is found for a specific precise problem, it also successfully deals with any underlying ambiguity within the problem by utilizing a technique based on the principles of linear transformation. Furthermore, the comparison between the analytical approach and the generalized hukuhara derivative approach is shown here, which illustrates the benefits of the analytical approach. The simulation is carried out in MATLAB.

mTOR signaling as a molecular target for the alleviation of Alzheimer's disease pathogenesis

Mechanistic/mammalian target of rapamycin (mTOR) belongs to the phosphatidylinositol kinase-related kinase (PIKK) family. mTOR signaling is required for the commencement of essential cell functions including autophagy. mTOR primarily governs cell growth in response to favourable nutrients and other growth stimuli. However, it also influences aging and other aspects of nutrient-related physiology such as protein synthesis, ribosome biogenesis, and cell proliferation in adults with very limited growth. The major processes for survival such as synaptic plasticity, memory storage and neuronal recovery involve a significant mTOR activity. mTOR dysregulation is becoming a prevalent motif in a variety of human diseases, including cancer, neurological disorders, and other metabolic syndromes. The use of rapamycin to prolong life in different animal models may be attributable to the multiple roles played by mTOR signaling in various processes involved in ageing, protein translation, autophagy, stem cell pool turnover, inflammation, and cellular senescence. mTOR activity was found to be altered in AD brains and rodent models, supporting the notion that aberrant mTOR activity is one of the key events contributing to the onset and progression of AD hallmarks This review assesses the molecular association between the mTOR signaling pathway and pathogenesis of Alzheimer's disease. The research data supporting this theme are also reviewed.

Vitis vinifera: An Alternative for the Prevention of Neurodegenerative Diseases

To present a systematic review of published studies in databases such as PUBMED, REDALYC, SCIELO, DIALNET, SCOPUS, EBSCO and CONRICYT related to the role-played by the components present in the vegetable oil of grape seed (Vitis vinífera) and the prevention or delay in the onset or progression of neurodegenerative diseases. The analysis of the research revealed that neurodegenerative diseases causes alterations in consciousness or in the nervous system leading to severe damage in neuronal cells, these pathologies are considered gradual and progressive. Various syndromes manifest the degenerative diseases of the nervous system; in some of them the predominant symptom is the progressive dementia. Among the components of the diet that in numerous epidemiological studies have shown an inverse association are vitamins, minerals, carotenoids, polyunsaturated fatty acids and polyphenols, the latter being the ones addressed in this document. There is an important evidence that a nutritional support based on polyunsaturated fatty acids and antioxidants can be applied to subjects with a history of neurodegenerative conditions in order to act as neuroprotectors. This requires the determination of the nutritional benefits of these nutrients or of nutraceuticals for the health of this group of patients.

G protein αq exerts expression level-dependent distinct signaling paradigms

G protein αq-coupled receptors (Gq-GPCRs) primarily signal through GαqGTP mediated phospholipase Cβ (PLCβ) stimulation and the subsequent hydrolysis of phosphatidylinositol 4, 5 bisphosphate (PIP2). Though Gq-heterotrimer activation results in both GαqGTP and Gβγ, unlike Gi/o-receptors, it is unclear if Gq-coupled receptors employ Gβγ as a major signal transducer. Compared to Gi/o- and Gs-coupled receptors, we observed that most cell types exhibit a limited free Gβγ generation upon Gq-pathway and Gαq/11 heterotrimer activation. We show that cells transfected with Gαq or endogenously expressing more than average-levels of Gαq/11 compared to Gαs and Gαi exhibit a distinct signaling regime primarily characterized by recovery-resistant PIP2 hydrolysis. Interestingly, the elevated Gq-expression is also associated with enhanced free Gβγ generation and signaling. Furthermore, the gene GNAQ, which encodes for Gαq, has recently been identified as a cancer driver gene. We also show that GNAQ is overexpressed in tumor samples of patients with Kidney Chromophobe (KICH) and Kidney renal papillary (KIRP) cell carcinomas in a matched tumor-normal sample analysis, which demonstrates the clinical significance of Gαq expression. Overall, our data indicates that cells usually express low Gαq levels, likely safeguarding cells from excessive calcium as wells as from Gβγ signaling.

Pharmacokinetics, bioavailability and tissue distribution study of JCC-02, a novel N-methyl-d-aspartate (NMDA) receptor inhibitor, in rats by LC-MS/MS

JCC-02, N-(3,5-dimethyladamantan-1-yl)-N'-(3-chlorophenyl) urea, has been developed as a novel N-methyl-d-aspartate (NMDA) receptor inhibitor for the treatment of Alzheimer's disease (AD). In this study, a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was developed to determine the concentration of JCC-02 in rat plasma and different tissues to investigate its pharmacokinetic behavior in vivo and distribution character in organs. The matrix samples were prepared by protein precipitation method with acetonitrile using gliclazide as the internal standard (IS). This validated method was successfully applied to JCC-02 pharmacokinetic study in rats after oral administration of low (0.7 mg·kg^-1), medium (2 mg·kg^-1) and high (6 mg·kg^-1) concentration, intravenous administration (2 mg·kg^-1) as well as tissue distribution in rats after administration of JCC-02 (2 mg·kg^-1) orally. The results indicated that the area under the time curve (AUC_0-∞) and peak plasma concentration (C_max) were directly proportional to dosage and the pharmacokinetic behavior of JCC-02 in rats was a linear process with respect to dosage. JCC-02 could be absorbed into blood circulation rapidly because of its short time to reach peak plasma concentration (t_max). Meanwhile, JCC-02 has a low clearance and a high volume of distribution, which might result in its long half-time. Oral absolute bioavailability (F) of JCC-02 was (14.61 ± 5.81)%, which was turned out to be low relatively. In tissues, the differences of JCC-02 concentration were quite large. After administration, small intestine (22.29 ± 15.86 μg·mL^-1), stomach (7.21 ± 2.87 μg·mL^-1), large intestine (1.27 ± 0.57 μg·mL^-1), liver (0.96 ± 0.52 μg·mL^-1) and fat (0.48 ± 0.24 μg·mL^-1) were the first five organs with the largest drug concentration. Small intestine could be the main part of drug absorption where most of the drug was distributed after oral administration. More importantly, JCC-02 could cross the blood-brain barrier (BBB), which may probably have a pretty good therapeutic effect on AD.

Analytically depicting the calcium diffusion for Alzheimer’s affected cell

Brain is the most complex structure of the human body. The processes going inside the brain and the mechanisms behind it have been unrevealed up to certain extent only. Out of the various physiological phenomena carried out by the brain, calcium signalling can be considered as one of the most important. Calcium being a second messenger plays an important role in transformation of various information. In view of above, an attempt has been made here to study calcium signalling in presence of buffers, i.e. one kind of proteins and endoplasmic reticulum (ER), which is also known as store house of the cell. Being the store house of the cell, it has very high amount of calcium, whereas buffers decrease the level of free calcium ions by binding calcium ions to it. A two-dimensional mathematical model has been developed to see the impact of these parameters on cytosolic calcium concentration. This mathematical model is solved analytically using Laplace transforms and similarity transforms. The simulations are carried out using MATLAB. It is observed that the impact of buffer and ER is significant on calcium signalling. The obtained results are interpreted with the Alzheimeric condition of the nerve cells.

Vitis vinifera acts as anti-Alzheimer's agent by modulating biochemical parameters implicated in cognition and memory

Background

Aluminum a known neuro and cholinotoxin has been implicated in the pathogenesis of Alzheimer’s disease. Its exposure is associated with impairment of the memory and cognition.

Objective

The present study was undertaken to evaluate the anti-Alzheimer’s activity of Vitis vinifera in aluminum induced Alzheimer’s disease.

Materials and methods

In this study, we investigated the behavioral and biochemical effects of aluminum in Sprague-Dawley rats. Animals were exposed to aluminum chloride (100 mg/kg/day) orally for a period of 8 weeks. Vitis was given in doses of 250 mg/kg and 500 mg/kg for 16 weeks and the possible effects of Vitis vinifera on the expression of Tau and amyloid precursor protein were evaluated by PCR analysis and the possible activities of lipid peroxidation, inflammation and anti-cholinesterase activity were evaluated.

Results

Aluminum intoxication was associated with significant impairment in learning and memory in Morris water maze test. A significant improvement was observed with Vitis vinifera in a dose dependent manner.

Conclusion

The findings of the present study revealed the significant neuroprotective actions of Vitis vinifera by modifying the biochemical parameters and inhibited the mRNA expression of Amyloid Precursor Protein and Tau, which are the key pathological hallmarks of Alzheimer’s disease, which was further confirmed by histopathological observations.

DELINEATION OF CALCIUM DIFFUSION IN ALZHEIMERIC BRAIN

Under the widespread umbrella of dementia, Alzheimer’s disease is the most common form of dementia. Most of the aged people are suffering from Alzheimer’s disease around the world. The reasons for the same are not known in detail and thus various experimental and computational attempts need to be carried out. Calcium, being a second messenger has an immense role in transformation of information. This transformation takes place in the form of signaling in which several parameters play an active role. In present work, an attempt has been made to describe the effect of calcium signaling in nerve cells for Alzheimer’s disease. Here, parameters like advection diffusion and buffering are taken into consideration to visualize the effects of the same on cytosolic calcium concentration. This physiological process is modeled two dimensionally and solved analytically. Laplace and similarity transforms are employed to obtain the desired results. The results are simulated and graphically plotted using MATLAB. The known fact that the higher concentration of calcium has adverse effects on the cell which may result into progression of AD is considered as a lantern in enlightening the physiology of Alzheimer’s disease.