scholarly journals Modeling the Heterodimer Interfaces of Melatonin Receptors

2021 ◽  
Vol 15 ◽  
Author(s):  
Lap Hang Tse ◽  
Yung Hou Wong

Melatonin receptors are Class A G protein-coupled receptors (GPCRs) that regulate a plethora of physiological activities in response to the rhythmic secretion of melatonin from the pineal gland. Melatonin is a key regulator in the control of circadian rhythm and has multiple functional roles in retinal physiology, memory, immunomodulation and tumorigenesis. The two subtypes of human melatonin receptors, termed MT1 and MT2, utilize overlapping signaling pathways although biased signaling properties have been reported in some cellular systems. With the emerging concept of GPCR dimerization, melatonin receptor heterodimers have been proposed to participate in system-biased signaling. Here, we used computational approaches to map the dimerization interfaces of known heterodimers of melatonin receptors, including MT1/MT2, MT1/GPR50, MT2/GPR50, and MT2/5-HT2C. By homology modeling and membrane protein docking analyses, we have identified putative preferred interface interactions within the different pairs of melatonin receptor dimers and provided plausible structural explanations for some of the unique pharmacological features of specific heterodimers previously reported. A thorough understanding of the molecular basis of melatonin receptor heterodimers may enable the development of new therapeutic approaches against aliments involving these heterodimeric receptors.

2021 ◽  
Vol 23 (1) ◽  
pp. 471
Author(s):  
Georgi Nikolaev ◽  
Ralitsa Robeva ◽  
Rossitza Konakchieva

The pineal hormone melatonin has attracted great scientific interest since its discovery in 1958. Despite the enormous number of basic and clinical studies the exact role of melatonin in respect to human physiology remains elusive. In humans, two high-affinity receptors for melatonin, MT1 and MT2, belonging to the family of G protein-coupled receptors (GPCRs) have been cloned and identified. The two receptor types activate Gi proteins and MT2 couples additionally to Gq proteins to modulate intracellular events. The individual effects of MT1 and MT2 receptor activation in a variety of cells are complemented by their ability to form homo- and heterodimers, the functional relevance of which is yet to be confirmed. Recently, several melatonin receptor genetic polymorphisms were discovered and implicated in pathology—for instance in type 2 diabetes, autoimmune disease, and cancer. The circadian patterns of melatonin secretion, its pleiotropic effects depending on cell type and condition, and the already demonstrated cross-talks of melatonin receptors with other signal transduction pathways further contribute to the perplexity of research on the role of the pineal hormone in humans. In this review we try to summarize the current knowledge on the membrane melatonin receptor activated cell signaling in physiology and pathology and their relevance to certain disease conditions including cancer.


2017 ◽  
Vol 3 (2) ◽  
pp. 183-186 ◽  
Author(s):  
Bernhard Wolf ◽  
Christian Scholze

AbstractNot only in the technological world (“Industry 4.0”), but also in medicine, a paradigmatic change is taking place: We are already on the threshold of “Medicine 4.0”. Molecular biology has long played a leading role in life sciences. Scientists now realise that, with increasing miniaturisation, microelectronic systems downsized to the dimensions of cellular systems will facilitate new therapeutic approaches. But conventional telecommunications systems can also be equipped with sensors and transformed into intelligent medical monitoring devices that can help patients become part of the diagnostic and therapeutic process. This article illustrates development trends that will lead to modern, electronically supported healthcare concepts.


2019 ◽  
Vol 20 (11) ◽  
pp. 2814 ◽  
Author(s):  
Jeremy S. Frieling ◽  
Conor C. Lynch

Parathyroid hormone-related protein (PTHrP), with isoforms ranging from 139 to 173 amino acids, has long been implicated in the development and regulation of multiple tissues, including that of the skeleton, via paracrine and autocrine signaling. PTHrP is also known as a potent mediator of cancer-induced bone disease, contributing to a vicious cycle between tumor cells and the bone microenvironment that drives the formation and progression of metastatic lesions. The abundance of roles ascribed to PTHrP have largely been attributed to the N-terminal 1–36 amino acid region, however, activities for mid-region and C-terminal products as well as additional shorter N-terminal species have also been described. Studies of the protein sequence have indicated that PTHrP is susceptible to post-translational proteolytic cleavage by multiple classes of proteases with emerging evidence pointing to novel functional roles for these PTHrP products in regulating cell behavior in homeostatic and pathological contexts. As a consequence, PTHrP products are also being explored as potential biomarkers of disease. Taken together, our enhanced understanding of the post-translational regulation of PTHrP bioactivity could assist in developing new therapeutic approaches that can effectively treat skeletal malignancies.


eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Nilkanth Patel ◽  
Xi Ping Huang ◽  
Jessica M Grandner ◽  
Linda C Johansson ◽  
Benjamin Stauch ◽  
...  

Melatonin receptors MT1 and MT2 are involved in synchronizing circadian rhythms and are important targets for treating sleep and mood disorders, type-2 diabetes and cancer. Here, we performed large scale structure-based virtual screening for new ligand chemotypes using recently solved high-resolution 3D crystal structures of agonist-bound MT receptors. Experimental testing of 62 screening candidates yielded the discovery of 10 new agonist chemotypes with sub-micromolar potency at MT receptors, with compound 21 reaching EC50 of 0.36 nM. Six of these molecules displayed selectivity for MT2 over MT1. Moreover, two most potent agonists, including 21 and a close derivative of melatonin, 28, had dramatically reduced arrestin recruitment at MT2, while compound 37 was devoid of Gi signaling at MT1, implying biased signaling. This study validates the suitability of the agonist-bound orthosteric pocket in the MT receptor structures for the structure-based discovery of selective agonists.


2011 ◽  
Vol 152 (39) ◽  
pp. 1552-1559 ◽  
Author(s):  
Katalin Dankó ◽  
Melinda Vincze

Inflammatory myopathies are chronic, immune-mediated diseases characterized with progressive proximal muscle weakness. They encompass a variety of syndromes with protean manifestations. The aims of therapy are to increase muscle strength, prevent the development of contractures, and to manage the systemic manifestations of the disease. This is a complex treatment which requires routine and wide knowledge. The most important task is to recognize the disease and guide the patient to immunologic center. Although the first line of therapy continues to include corticosteroids, there are a multitude of agents available for treating patients with myositis. There are several different immunosuppressive agents which may be applied alone or in combination with each other, as well as an increasing number of novel and exciting biologic agents targeting molecules participating in the pathogenesis of inflammatory myopathy. Physiotherapy and rehabilitation in the remission period may significantly improve the functional outcome of patients with these disorders. Orv. Hetil., 2011, 152, 1552–1559.


Epigenomes ◽  
2020 ◽  
Vol 4 (3) ◽  
pp. 18
Author(s):  
Murat Toruner ◽  
Martin E. Fernandez-Zapico ◽  
Christopher L. Pin

Pancreatic cancer remains among the deadliest forms of cancer with a 5 year survival rate less than 10%. With increasing numbers being observed, there is an urgent need to elucidate the pathogenesis of pancreatic cancer. While both contribute to disease progression, neither genetic nor environmental factors completely explain susceptibility or pathogenesis. Defining the links between genetic and environmental events represents an opportunity to understand the pathogenesis of pancreatic cancer. Epigenetics, the study of mitotically heritable changes in genome function without a change in nucleotide sequence, is an emerging field of research in pancreatic cancer. The main epigenetic mechanisms include DNA methylation, histone modifications and RNA interference, all of which are altered by changes to the environment. Epigenetic mechanisms are being investigated to clarify the underlying pathogenesis of pancreatic cancer including an increasing number of studies examining the role as possible diagnostic and prognostic biomarkers. These mechanisms also provide targets for promising new therapeutic approaches for this devastating malignancy.


Immuno ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 174-193
Author(s):  
Jenny Valentina Garmendia ◽  
Juan Bautista De Sanctis

NK cells are lymphocytes involved in the innate and adaptative immune response. These cells are located in peripheral blood and tissues with ample functions, from immune vigilant to tolerogenic reactions. In the endometrium, NK cell populations vary depending on age, hormones, and inflammation. When pregnancy occurs, tissue-resident NK cells and conventional NK cells are recruited to protect the fetus, a tolerogenic response. On the contrary, in the inflamed endometrium, various inflammatory cells down-regulate NK tolerance and impair embryo implantation. Therefore, NK cells’ pharmacological modulation is difficult to achieve. Several strategies have been used, from progesterone, lipid emulsions to steroids; the success has not been as expected. However, new therapeutic approaches have been proposed to decrease the endometrial inflammatory burden and increase pregnancy success based on understanding NK cell physiology.


Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 457
Author(s):  
Andreu Blanquer ◽  
Jana Musilkova ◽  
Elena Filova ◽  
Johanka Taborska ◽  
Eduard Brynda ◽  
...  

Chronic wounds affect millions of patients worldwide, and it is estimated that this number will increase steadily in the future due to population ageing. The research of new therapeutic approaches to wound healing includes the development of nanofibrous meshes and the use of platelet lysate (PL) to stimulate skin regeneration. This study considers a combination of a degradable electrospun nanofibrous blend of poly(L-lactide-co-ε-caprolactone) and poly(ε-caprolactone) (PLCL/PCL) membranes (NF) and fibrin loaded with various concentrations of PL aimed at the development of bioactive skin wound healing dressings. The cytocompatibility of the NF membranes, as well as the effect of PL, was evaluated in both monocultures and co-cultures of human keratinocytes and human endothelial cells. We determined that the keratinocytes were able to adhere on all the membranes, and their increased proliferation and differentiation was observed on the membranes that contained fibrin with at least 50% of PL (Fbg + PL) after 14 days. With respect to the co-culture experiments, the membranes with fibrin with 20% of PL were observed to enhance the metabolic activity of endothelial cells and their migration, and the proliferation and differentiation of keratinocytes. The results suggest that the newly developed NF combined with fibrin and PL, described in the study, provides a promising dressing for chronic wound healing purposes.


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