Potentiating the Benefits of Melatonin through Chemical Functionalization: Possible Impact on Multifactorial Neurodegenerative Disorders

The role of mitochondrial transfer via tunneling nanotubes in the central nervous system: A review

Tumour necrosis factor alpha-induced protein 2 (TNFAIP2) is a gene induced by tumor necrosis factor in endothelial cells. TNFAIP2 has important functions in physiological and pathological processes, including cell proliferation, adhesion, migration, angiogenesis, inflammation, tunneling nanotube (TNT) formation and tumorigenesis. Moreover, TNFAIP2 is the key factor in the formation of TNTs. TNTs are related to signal transduction between different cell types and are considered a novel means of cell-to-cell communication. Mesenchymal stem cells (MSCs) are pluripotent cells that exhibit self-renewal, multidirectional differentiation, paracrine function and immune-regulating ability. MSCs can transfer mitochondria through TNTs to improve the functions of target cells. This review revealed that TNFAIP2 promotes the formation of TNTs and that MSCs rely on TNTs for mitochondrial transfer to ameliorate cell dysfunction.

The role of melatonin in amyloid beta-induced inflammation mediated by inflammasome signaling in neuronal cell lines

Alzheimer's disease (AD) is the most prevalent neurodegenerative disorder. In addition to amyloid beta (Aβ) and tau, neuroinflammation is a crucial element in the etiology of this disease. However, the relevance of inflammasome-induced pyroptosis to AD is unknown. We aimed to clarify whether the anti-inflammatory effects of melatonin could prevent Aβ-mediated activation of the inflammasome. We demonstrated that Aβ upregulated NOD-like receptor family pyrin domain-containing 3 (NLRP3), apoptosis-associated speck-like protein containing a CARD, and cysteinyl aspartate-specific proteinase caspase (caspase 1) expression in SH-SY5Y neuroblastoma cells, resulting in the release of proinflammatory cytokines, including interleukin-1β (IL-1β), interleukin-18 (IL-18) and tumor necrosis factor (TNF-α). Melatonin prevented inflammasome signaling and excessive cytokine release caused by Aβ. We found that ethyl 2[(2-chlorophenyl)(hydroxy) methyl]acrylate (INF-4E, NLRP3 and caspase 1 inhibitor) significantly abolished Aβ-induced proinflammatory cytokine expression. The increase in cleaved-caspase 1, pro-IL18, and cleaved-IL18 caused by Aβ suggested the occurrence of pyroptosis, which was further confirmed by the increased expression of N-terminal gasdermin D (N-GSDMD). Melatonin plays a protective role against Aβ-induced inflammation via an inflammasome-associated mechanism that is essential in inducing the active forms of cytokines and pyroptosis. The ability of melatonin to inhibit inflammasome may represent a turning point in the treatment of AD progression.

Melatonin as mitochondria-targeted drug

Oxidative damage is associated to numerous diseases as well as aging development. Mitochondria found in most eukaryotic organisms to create the energy of the cell, generate free radicals during its action and they are chief targets of the oxidants. Mitochondrial activities outspread outside the borders of the cell and effect human physiology by modulating interactions among cells and tissues. Therefore, it has been implicated in several human disorders and conditions. Melatonin (MLT) is an endogenously created indole derivative that modifies several tasks, involving mitochondria-associated activities. These possessions make MLT a powerful defender against a selection of free radical-linked disorders. MLT lessens mitochondrial anomalies causing from extreme oxidative stress and may improve mitochondrial physiology. It is a potent and inducible antioxidant for mitochondria. MLT is produced in mitochondria of conceivably of all cells and it also appears to be a mitochondria directed antioxidant which has related defensive properties as the synthesized antioxidant molecules. This chapter summarizes the suggestion that MLT is produced in mitochondria as well as disorders of mitochondrial MLT production that may associate to a number of mitochondria-linked diseases. MLT as a mitochondria-targeted drug is also discussed.

CADMA-Chem: A Computational Protocol Based on Chemical Properties Aimed to Design Multifunctional Antioxidants

A computational protocol aimed to design new antioxidants with versatile behavior is presented. It is called Computer-Assisted Design of Multifunctional Antioxidants and is based on chemical properties (CADMA-Chem). The desired multi-functionality consists of in different methods of antioxidant protection combined with neuroprotection, although the protocol can also be used to pursue other health benefits. The dM38 melatonin derivative is used as a study case to illustrate the protocol in detail. This was found to be a highly promising candidate for the treatment of neurodegeneration, in particular Parkinson's and Alzheimer's diseases. This also has the desired properties of an oral-drug, which is significantly better than Trolox for scavenging free radicals, and has chelates redox metals, prevents the ●OH production, via Fenton-like reactions, repairs oxidative damage in biomolecules (lipids, proteins, and DNA), and acts as a polygenic neuroprotector by inhibiting catechol-O-methyl transferase (COMT), acetylcholinesterase (AChE) and monoamine oxidase B (MAOB). To the best of our best knowledge, CADMA-Chem is currently the only protocol that simultaneously involves the analyses of drug-like behavior, toxicity, manufacturability, versatile antioxidant protection, and receptor-ligand binding affinities. It is expected to provide a starting point that helps to accelerate the discovery of oral drugs with the potential to prevent, or slow down, multifactorial human health disorders.

Tunneling nanotubes and mesenchymal stem cells: New insights into the role of melatonin in neuronal recovery

Efficient cell-to-cell communication is essential for tissue development, homeostasis, and the maintenance of cellular functions after injury. Tunneling nanotubes (TNTs) have emerged as a new important method of cell-to-cell communication. TNTs are primarily established between stressed and unstressed cells and can transport a variety of cellular components. Mitochondria are important trafficked entities through TNTs. Transcellular mitochondria transfer permits the incorporation of healthy mitochondria into the endogenous network of recipient cells, changing the bioenergetic profile and other functional properties of the recipient and may allow the recipient cells to recuperate from apoptotic processes and return to a normal operating state. Mesenchymal cells (MSCs) can form TNTs and transfer mitochondria and other constituents to target cells. This occurs under both physiological and pathological conditions, leading to changes in cellular energy metabolism and functions. This review summarizes the newly described capacity of melatonin to improve mitochondrial fusion/fission dynamics and promote TNT formation. This new evidence suggests that melatonin's protective effects could be attributed to its ability to prevent mitochondrial damage in injured cells, reduce senescence, and promote anastasis, a natural cell recovery phenomenon that rescues cells from the brink of death. The modulation of these new routes of intercellular communication by melatonin could play a key role in increasing the therapeutic potential of MSCs.