A new fluorescent probe for the visualization of progerin.

Hutchinson-Gilford progeria syndrome (HGPS) or progeria is a rare genetic disease that causes premature aging, leading to a drastic reduction in the life expectancy of patients. Progeria is mainly caused by the intracellular accumulation of a defective protein called progerin, generated from a mutation in the LMNA gene. Currently, there is only one approved drug for the treatment of progeria, which has limited efficacy. It is believed that progerin levels are the most important biomarker related to the severity of the disease. However, there is a lack of effective tools to directly visualize progerin in the native cellular models, since the commercially available antibodies are not well suited for the direct visualization of progerin in cells from the mouse model of the disease. In this context, an alternative option for the visualization of a protein relies on the use of fluorescent chemical probes, molecules with affinity and specificity towards a protein. In this work we report the synthesis and characterization of a new fluorescent probe (UCM-23079) that allows for the direct visualization of progerin in cells from the most widely used progeroid mouse model. Thus, UCM-23079 is a new tool compound that could help prioritize potential preclinical therapies towards the final goal of finding a definitive cure for progeria.

New Pharmacological Approaches for Rare Diseases.

The expression "rare disease" describes a group of diseases whose individual prevalence is low (between 3.9 and 6.6 in 10,000 subjects depending on the country) but which in total affect up to the 3-6% of the worldwide population [...].

Small-Molecule Therapeutic Perspectives for the Treatment of Progeria.

Hutchinson-Gilford progeria syndrome (HGPS), or progeria, is an extremely rare disorder that belongs to the class of laminopathies, diseases characterized by alterations in the genes that encode for the lamin proteins or for their associated interacting proteins. In particular, progeria is caused by a point mutation in the gene that codifies for the lamin A gene. This mutation ultimately leads to the biosynthesis of a mutated version of lamin A called progerin, which accumulates abnormally in the nuclear lamina. This accumulation elicits several alterations at the nuclear, cellular, and tissue levels that are phenotypically reflected in a systemic disorder with important alterations, mainly in the cardiovascular system, bones, skin, and overall growth, which results in premature death at an average age of 14.5 years. In 2020, lonafarnib became the first (and only) FDA approved drug for treating progeria. In this context, the present review focuses on the different therapeutic strategies currently under development, with special attention to the new small molecules described in recent years, which may represent the upcoming first-in-class drugs with new mechanisms of action endowed with effectiveness not only to treat but also to cure progeria.

Blocking Ras inhibition as an antitumor strategy.

Ras proteins are among the most frequently mutated drivers in human cancer and remain an elusive pharmaceutical targeting. Previous studies have improved the understanding of Ras structure, processing, and signaling pathways in cancer cells and have opened new possibilities for inhibiting Ras function. In this review we discuss the most recent advances towards inhibiting Ras activity with small molecules, highlighting the two approaches: (i) compounds that bind directly to Ras protein and (ii) inhibitors of the enzymes involved in the post-translational modifications of Ras. In the former, we analyze the most recent contributions in each of the main classes of Ras direct binders, including the different types of nucleotide exchange inhibitors, allosteric compounds, and molecules that interfere with the interaction between Ras and its effectors. In the latter, we examine the compounds that inhibit Ras activation by blocking any of its post-translational modifications. Also, a special focus is made on those molecules that have progressed the farthest from medicinal chemistry and drug development points of view. Finally, the current scene regarding the clinical trials of Ras inhibitors, together with the future promising avenues for further development of the challenging Ras field are reviewed.

2-Arachidonoylglycerol Reduces Proteoglycans and Enhances Remyelination in a Progressive Model of Demyelination.

The failure to undergo remyelination is a critical impediment to recovery in multiple sclerosis. Chondroitin sulfate proteoglycans (CSPGs) accumulate at demyelinating lesions creating a nonpermissive environment that impairs axon regeneration and remyelination. Here, we reveal a new role for 2-arachidonoylglycerol (2-AG), the major CNS endocannabinoid, in the modulation of CSPGs deposition in a progressive model of multiple sclerosis, the Theiler's murine encephalomyelitis virus-induced demyelinating disease. Treatment with a potent reversible inhibitor of the enzyme monoacylglycerol lipase, which accounts for 85% of the 2-AG degradation in the mouse CNS, modulates neuroinflammation and reduces CSPGs accumulation and astrogliosis around demyelinated lesions in the spinal cord of Theiler's murine encephalomyelitis virus-infected mice. Inhibition of 2-AG hydrolysis augments the number of mature oligodendrocytes and increases MBP, leading to remyelination and functional recovery of mice. Our findings establish a mechanism for 2-AG promotion of remyelination with implications in axonal repair in CNS demyelinating pathologies.SIGNIFICANCE STATEMENT The deposition of chondroitin sulfate proteoglycans contributes to the failure in remyelination associated with multiple sclerosis. Here we unveil a new role for 2-arachidonoylglycerol, the major CNS endocannabinoid, in the modulation of chondroitin sulfate proteoglycan accumulation in Theiler's murine encephalomyelitis virus-induced demyelinating disease. The treatment during the chronic phase with a potent reversible inhibitor of the enzyme monoacylglycerol lipase, which accounts for 85% of the 2-arachidonoylglycerol degradation in the mouse CNS, modulates neuroinflammation and reduces chondroitin sulfate proteoglycan deposition around demyelinated lesions in the spinal cord of Theiler's murine encephalomyelitis virus-infected mice. The increased 2-arachidonoylglycerol tone promotes remyelination in a model of progressive multiple sclerosis ameliorating motor dysfunction.

2-AG limits Theiler's virus induced acute neuroinflammation by modulating microglia and promoting MDSCs.

The innate immune response is mediated by primary immune modulators such as cytokines and chemokines that together with immune cells and resident glia orchestrate CNS immunity and inflammation. Growing evidence supports that the endocannabinoid 2-arachidonoylglycerol (2-AG) exerts protective actions in CNS injury models. Here, we used the acute phase of Theiler's virus induced demyelination disease (TMEV-IDD) as a model of acute neuroinflammation to investigate whether 2-AG modifies the brain innate immune responses to TMEV and CNS leukocyte trafficking. 2-AG or the inhibition of its hydrolysis diminished the reactivity and number of microglia at the TMEV injection site reducing their morphological complexity and modulating them towards an anti-inflammatory state via CB2 receptors. Indeed, 2-AG dampened the infiltration of immune cells into the CNS and inhibited their egress from the spleen, resulting in long-term beneficial effects at the chronic phase of the disease. Intriguingly, it is not a generalized action over leukocytes since 2-AG increased the presence and suppressive potency of myeloid derived suppressor cells (MDSCs) in the brain resulting in higher apoptotic CD4+ T cells at the injection site. Together, these data suggest a robust modulatory effect in the peripheral and central immunity by 2-AG and highlight the interest of modulating endogenous cannabinoids to regulate CNS inflammatory conditions.

A Fluorescent Probe to Unravel Functional Features of Cannabinoid Receptor CB1 in Human Blood and Tonsil Immune System Cells.

The human endogenous cannabinoid system (ECS) regulates key physiological processes and alterations in its signaling pathways, and endocannabinoid levels are associated with diseases such as neurological and neuropsychiatric conditions, cancer, pain and inflammation, obesity, and metabolic and different immune related disorders. Immune system cells express the G-protein coupled cannabinoid receptor 1 (CB1), but its functional role has not been fully understood, likely due to the lack of appropriate tools. The availability of novel tools to investigate the role of CB1 in immune regulation might contribute to identify CB1 as a potential novel therapeutic target or biomarker for many diseases. Herein, we report the development and validation of the first fluorescent small molecule probe to directly visualize and quantify CB1 in blood and tonsil immune cells by flow cytometry and confocal microscopy. We coupled the cannabinoid agonist HU210 to the fluorescent tag Alexa Fluor 488, generating a fluorescent probe with high affinity for CB1 and selectivity over CB2. We validate HU210-Alexa488 for the rapid, simultaneous, and reproducible identification of CB1 in human monocytes, T cells, and B cells by multiplexed flow cytometry. This probe is also suitable for the direct visualization of CB1 in tonsil tissues, allowing the in vivo identification of tonsil CB1-expressing T and B cells. This study provides the first fluorescent chemical tool to investigate CB1 expression and function in human blood and tonsil immune cells, which might well pave the way to unravel essential features of CB1 in different immune and ECS-related diseases.

Development of a Fluorescent Bodipy Probe for Visualization of the Serotonin 5-HT1A Receptor in Native Cells of the Immune System.

Serotonin (5-HT) modulates key aspects of the immune system. However, its precise function and the receptors involved in the observed effects have remained elusive. Among the different serotonin receptors, 5-HT1A plays an important role in the immune system given its presence in cells involved in both the innate and adaptive immune responses, but its actual levels of expression under different conditions have not been comprehensively studied due to the lack of suitable tools. To further clarify the role of 5-HT1A receptor in the immune system, we have developed a fluorescent small molecule probe that enables the direct study of the receptor levels in native cells. This probe allows direct profiling of the receptor expression in immune cells using flow cytometry. Our results show that important subsets of immune cells including human monocytes and dendritic cells express functional 5-HT1A and that its activation is associated with anti-inflammatory signaling. Furthermore, application of the probe to the experimental autoimmune encephalomyelitis model of multiple sclerosis demonstrates its potential to detect the specific overexpression of the 5-HT1A receptor in CD4+ T cells. Accordingly, the probe reported herein represents a useful tool whose use can be extended to study the levels of 5-HT1A receptor in ex vivo samples of different immune system conditions.

Development of a Nucleotide Exchange Inhibitor That Impairs Ras Oncogenic Signaling.

Despite more than three decades of intense effort, no anti-Ras therapies have reached clinical application. Contributing to this failure has been an underestimation of Ras complexity and a dearth of structural information. In this regard, recent studies have revealed the highly dynamic character of the Ras surface and the existence of transient pockets suitable for small-molecule binding, opening up new possibilities for the development of Ras modulators. Herein, a novel Ras inhibitor (compound 12) is described that selectively impairs mutated Ras activity in a reversible manner without significantly affecting wild-type Ras, reduces the Ras-guanosine triphosphate (GTP) levels, inhibits the activation of the mitogen-activated protein kinase (MAPK) pathway, and exhibits remarkable cytotoxic activity in Ras-driven cellular models. The use of molecular dynamics simulations and NMR spectroscopy experiments has enabled the molecular bases responsible for the interactions between compound 12 and Ras protein to be explored. The new Ras inhibitor binds partially to the GTP-binding region and extends into the adjacent hydrophobic pocket delimited by switch II. Hence, Ras inhibitor 12 could represent a new compound for the development of more efficacious drugs to target Ras-driven cancers; a currently unmet clinical need.

Chemoproteomic Approach to Explore the Target Profile of GPCR ligands: Application to 5-HT1A and 5-HT6 Receptors.

Determination of the targets of a compound remains an essential aspect in drug discovery. A complete understanding of all binding interactions is critical to recognize in advance both therapeutic effects and undesired consequences. However, the complete polypharmacology of many drugs currently in clinical development is still unknown, especially in the case of G protein-coupled receptor (GPCR) ligands. In this work we have developed a chemoproteomic platform based on the use of chemical probes to explore the target profile of a compound in biological systems. As proof of concept, this methodology has been applied to selected ligands of the therapeutically relevant serotonin 5-HT1A and 5-HT6 receptors, and we have identified and validated some of their off-targets. This approach could be extended to other drugs of interest to study the targeted proteome in disease-relevant systems.

A reversible and selective inhibitor of monoacylglycerol lipase ameliorates multiple sclerosis.

Monoacylglycerol lipase (MAGL) is the enzyme responsible for the inactivation of the endocannabinoid 2-arachidonoylglycerol (2-AG). MAGL inhibitors show analgesic and tissue-protecting effects in several disease models. However, the few efficient and selective MAGL inhibitors described to date block the enzyme irreversibly, and this can lead to pharmacological tolerance. Hence, additional classes of MAGL inhibitors are needed to validate this enzyme as a therapeutic target. Here we report a potent, selective, and reversible MAGL inhibitor (IC50=0.18 µM) which is active in vivo and ameliorates the clinical progression of a multiple sclerosis (MS) mouse model without inducing undesirable CB1 -mediated side effects. These results support the interest in MAGL as a target for the treatment of MS.

The anxiolytic effect of cannabidiol on chronically stressed mice depends on hippocampal neurogenesis: involvement of the endocannabinoid system.

Cannabidiol (CBD), the main non-psychotomimetic component of the plant Cannabis sativa, exerts therapeutically promising effects on human mental health such as inhibition of psychosis, anxiety and depression. However, the mechanistic bases of CBD action are unclear. Here we investigate the potential involvement of hippocampal neurogenesis in the anxiolytic effect of CBD in mice subjected to 14 d chronic unpredictable stress (CUS). Repeated administration of CBD (30 mg/kg i.p., 2 h after each daily stressor) increased hippocampal progenitor proliferation and neurogenesis in wild-type mice. Ganciclovir administration to GFAP-thymidine kinase (GFAP-TK) transgenic mice, which express thymidine kinase in adult neural progenitor cells, abrogated CBD-induced hippocampal neurogenesis. CBD administration prevented the anxiogenic effect of CUS in wild type but not in GFAP-TK mice as evidenced in the novelty suppressed feeding test and the elevated plus maze. This anxiolytic effect of CBD involved the participation of the CB1 cannabinoid receptor, as CBD administration increased hippocampal anandamide levels and administration of the CB1-selective antagonist AM251 prevented CBD actions. Studies conducted with hippocampal progenitor cells in culture showed that CBD promotes progenitor proliferation and cell cycle progression and mimics the proliferative effect of CB1 and CB2 cannabinoid receptor activation. Moreover, antagonists of these two receptors or endocannabinoid depletion by fatty acid amide hydrolase overexpression prevented CBD-induced cell proliferation. These findings support that the anxiolytic effect of chronic CBD administration in stressed mice depends on its proneurogenic action in the adult hippocampus by facilitating endocannabinoid-mediated signalling.

Dual inhibition of alpha/beta-hydrolase domain 6 and fatty acid amide hydrolase increases endocannabinoid levels in neurons.

Agonists at cannabinoid receptors, such as the phytocannabinoid Δ(9)-tetrahydrocannabinol, exert a remarkable array of therapeutic effects but are also associated with undesirable psychoactive side effects. Conversely, targeting enzymes that hydrolyze endocannabinoids (eCBs) allows for more precise fine-tuning of cannabinoid receptor signaling, thus providing therapeutic relief with reduced side effects. Here, we report the development and characterization of an inhibitor of eCB hydrolysis, UCM710, which augments both N-arachidonoylethanolamine and 2-arachidonoylglycerol levels in neurons. This compound displays a unique pharmacological profile in that it inhibits fatty acid amide hydrolase and α/ß-hydrolase domain 6 but not monoacylglycerol lipase. Thus, UCM710 represents a novel tool to delineate the therapeutic potential of compounds that manipulate a subset of enzymes that control eCB signaling.

Chemical probes for the recognition of cannabinoid receptors in native systems.

Receptors made visible: The described biotin-tagged small-molecule probes with excellent affinities for the CB(1) and CB(2) cannabinoid receptors (CB(1)R and CB(2)R) enable direct visualization of these receptors in native cellular systems, including neurons, microglia, and immune cells. This method could overcome some of the limitations of current methodologies and may help to dissect the complexity of the endogenous cannabinoid system.

New Trends in Aging Drug Discovery.

Aging is considered the main risk factor for many chronic diseases that frequently appear at advanced ages. However, the inevitability of this process is being questioned by recent research that suggests that senescent cells have specific features that differentiate them from younger cells and that removal of these cells ameliorates senescent phenotype and associated diseases. This opens the door to the design of tailored therapeutic interventions aimed at reducing and delaying the impact of senescence in life, that is, extending healthspan and treating aging as another chronic disease. Although these ideas are still far from reaching the bedside, it is conceivable that they will revolutionize the way we understand aging in the next decades. In this review, we analyze the main and well-validated cellular pathways and targets related to senescence as well as their implication in aging-associated diseases. In addition, the most relevant small molecules with senotherapeutic potential, with a special emphasis on their mechanism of action, ongoing clinical trials, and potential limitations, are discussed. Finally, a brief overview of alternative strategies that go beyond the small molecule field, together with our perspectives for the future of the field, is provided.

Novel Antagonist of the Type 2 Lysophosphatidic Acid Receptor (LPA2), UCM-14216, Ameliorates Spinal Cord Injury in Mice.

Spinal cord injuries (SCIs) irreversibly disrupt spinal connectivity, leading to permanent neurological disabilities. Current medical treatments for reducing the secondary damage that follows the initial injury are limited to surgical decompression and anti-inflammatory drugs, so there is a pressing need for new therapeutic strategies. Inhibition of the type 2 lysophosphatidic acid receptor (LPA2) has recently emerged as a new potential pharmacological approach to decrease SCI-associated damage. Toward validating this receptor as a target in SCI, we have developed a new series of LPA2 antagonists, among which compound 54 (UCM-14216) stands out as a potent and selective LPA2 receptor antagonist (Emax = 90%, IC50 = 1.9 µM, KD = 1.3 nM; inactive at LPA1,3-6 receptors). This compound shows efficacy in an in vivo mouse model of SCI in an LPA2-dependent manner, confirming the potential of LPA2 inhibition for providing a new alternative for treating SCI.

A novel inhibitor of fatty acid synthase shows activity against HER2+ breast cancer xenografts and is active in anti-HER2 drug-resistant cell lines.

INTRODUCTION: Inhibiting the enzyme Fatty Acid Synthase (FASN) leads to apoptosis of breast carcinoma cells, and this is linked to human epidermal growth factor receptor 2 (HER2) signaling pathways in models of simultaneous expression of FASN and HER2. METHODS: In a xenograft model of breast carcinoma cells that are FASN+ and HER2+, we have characterised the anticancer activity and the toxicity profile of G28UCM, the lead compound of a novel family of synthetic FASN inhibitors. In vitro, we analysed the cellular and molecular interactions of combining G28UCM with anti-HER drugs. Finally, we tested the cytotoxic ability of G28UCM on breast cancer cells resistant to trastuzumab or lapatinib, that we developed in our laboratory. RESULTS: In vivo, G28UCM reduced the size of 5 out of 14 established xenografts. In the responding tumours, we observed inhibition of FASN activity, cleavage of poly-ADPribose polymerase (PARP) and a decrease of p-HER2, p- protein kinase B (AKT) and p-ERK1/2, which were not observed in the nonresponding tumours. In the G28UCM-treated animals, no significant toxicities occurred, and weight loss was not observed. In vitro, G28UCM showed marked synergistic interactions with trastuzumab, lapatinib, erlotinib or gefitinib (but not with cetuximab), which correlated with increases in apoptosis and with decreases in the activation of HER2, extracellular signal-regulated kinase (ERK)1/2 and AKT. In trastuzumab-resistant and in lapatinib-resistant breast cancer cells, in which trastuzumab and lapatinib were not effective, G28UCM retained the anticancer activity observed in the parental cells. CONCLUSIONS: G28UCM inhibits fatty acid synthase (FASN) activity and the growth of breast carcinoma xenografts in vivo, and is active in cells with acquired resistance to anti-HER2 drugs, which make it a candidate for further pre-clinical development.

Isoprenylcysteine Carboxylmethyltransferase-Based Therapy for Hutchinson-Gilford Progeria Syndrome.

Hutchinson-Gilford progeria syndrome (HGPS, progeria) is a rare genetic disease characterized by premature aging and death in childhood for which there were no approved drugs for its treatment until last November, when lonafarnib obtained long-sought FDA approval. However, the benefits of lonafarnib in patients are limited, highlighting the need for new therapeutic strategies. Here, we validate the enzyme isoprenylcysteine carboxylmethyltransferase (ICMT) as a new therapeutic target for progeria with the development of a new series of potent inhibitors of this enzyme that exhibit an excellent antiprogeroid profile. Among them, compound UCM-13207 significantly improved the main hallmarks of progeria. Specifically, treatment of fibroblasts from progeroid mice with UCM-13207 delocalized progerin from the nuclear membrane, diminished its total protein levels, resulting in decreased DNA damage, and increased cellular viability. Importantly, these effects were also observed in patient-derived cells. Using the Lmna G609G/G609G progeroid mouse model, UCM-13207 showed an excellent in vivo efficacy by increasing body weight, enhancing grip strength, extending lifespan by 20%, and decreasing tissue senescence in multiple organs. Furthermore, UCM-13207 treatment led to an improvement of key cardiovascular hallmarks such as reduced progerin levels in aortic and endocardial tissue and increased number of vascular smooth muscle cells (VSMCs). The beneficial effects go well beyond the effects induced by other therapeutic strategies previously reported in the field, thus supporting the use of UCM-13207 as a new treatment for progeria.

The constitutive production of the endocannabinoid 2-arachidonoylglycerol participates in oligodendrocyte differentiation.

Endocannabinoids have recently emerged as instructive cues in the developing central nervous system, and, based on the expression of their receptors, we identified oligodendrocytes as potential targets of these molecules. Here, we show that the enzymes responsible for the synthesis of the endocannabinoid 2-arachidonoylglycerol (2-AG), diacylglycerol lipase alpha (DAGLα) and beta (DAGLß), and degradation, monoacylglycerol lipase (MAGL), can be found in oligodendrocytes at different developmental stages. Moreover, cultured oligodendrocyte progenitor cells (OPCs) express DAGLα and ß abundantly, resulting in the stronger production of 2-AG than in differentiated oligodendrocytes. The opposite is observed with MAGL. CB1 and CB2 receptor antagonists (SR141716 and AM630) impaired OPC differentiation into mature oligodendrocytes and likewise, inhibiting DAGL activity with RHC-80267 or tetrahydrolipstatin also blocked oligodendrocyte maturation, an effect reversed by the addition of exogenous 2-AG. Likewise, 2-AG synthesis disruption using specific siRNAs against DAGLα and DAGLß significantly reduced myelin protein expression in vitro, whereas a pharmacological gain-of-function approach by using cannabinoid agonists or MAGL inhibition had the opposite effects. ERK/MAPK pathway is implicated in oligodendrocyte differentiation because PD98059, an inhibitor of MEK1, abrogated oligodendrocyte maturation. The cannabinoid receptor antagonists and RHC-80267 all diminished basal ERK1/2 phosphorylation, effects that were partially reversed by the addition of 2-AG. Overall, our data suggest a novel role of endocannabinoids in oligodendrocyte differentiation such that constitutive release of 2-AG activates cannabinoid receptors in an autocrine/paracrine way in OPCs, stimulating the ERK/MAPK signaling pathway.