Publications by authors named "Ponimaskin E"

Immune-checkpoint-inhibitors (ICI) target key regulators of the immune system expressed by cancer cells that mask those from recognition by the immune system. They have improved the outcome for patients with various cancer types, such as melanoma. ICI-based therapy is frequently accompanied by immune-related adverse side effects (IRAEs).

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The hormone and neurotransmitter serotonin regulates numerous physiological functions within the central nervous system and in the periphery upon binding to specific receptors. In the periphery, the serotonin receptor 7 (5-HT7R) is expressed on different immune cells including monocytes and macrophages. To investigate the impact of 5-HT7R-mediated signaling on macrophage properties, we used human THP-1 cells and differentiated them into pro-inflammatory M1- and anti-inflammatory M2-like macrophages.

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Background: Homo- and heteromerization of G protein-coupled receptors (GPCRs) plays an important role in the regulation of receptor functions. Recently, we demonstrated an interaction between the serotonin receptor 7 (5-HT7R), a class A GPCR, and the cell adhesion molecule CD44. However, the functional consequences of this interaction on 5-HT7R-mediated signaling remained enigmatic.

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Stress resilience is the ability of neuronal networks to maintain their function despite the stress exposure. Using a mouse model we investigate stress resilience phenomenon. To assess the resilient and anhedonic behavioral phenotypes developed after the induction of chronic unpredictable stress, we quantitatively characterized the structural and functional plasticity of excitatory synapses in the hippocampus using a combination of proteomic, electrophysiological, and imaging methods.

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Article Synopsis
  • Tegaserod is a selective agonist of serotonin receptors and is primarily used to treat bowel diseases, which led researchers to investigate its effects on human cardiac atrial 5-HT receptors.
  • In mice with cardiac-specific overexpression of these receptors, tegaserod demonstrated positive effects on heart muscle contraction and rate, while showing no such effects in normal mice.
  • The study revealed that tegaserod enhances contraction strength in human atrial tissue, particularly when combined with cilostamide, though it acts as a partial agonist compared to serotonin and isoprenaline.
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Spinal Muscular Atrophy (SMA) is a neuromuscular disease caused by low levels of the Survival of Motoneuron (SMN) protein. SMN interacts with and regulates the actin-binding protein profilin2a, thereby influencing actin dynamics. Dysfunctional actin dynamics caused by SMN loss disrupts neurite outgrowth, axonal pathfinding, and formation of functional synapses in neurons.

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Serotonin regulates multiple physiological and pathological processes in the brain, including mood and cognition. The serotonin receptors 5-HT1AR (also known as HTR1A) and 5-HT7R (also known as HTR7) have emerged as key players in stress-related disorders, particularly depression. These receptors can form heterodimers, which influence their functions.

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The aim of this study was to determine the anti-hypersensitivity activity of novel non-hallucinogenic compounds derived from iboga alkaloids (i.e., ibogalogs), including tabernanthalog (TBG), ibogainalog (IBG), and ibogaminalog (DM506), using mouse models of neuropathic (Chronic Constriction Injury; CCI) and visceral pain (dextrane sulfate sodium; DSS).

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Article Synopsis
  • Neurodegenerative diseases like tauopathies are linked to abnormal protein aggregation, particularly involving hyperphosphorylated Tau, which is influenced by the serotonin receptor 7 (5-HT7R) through the activation of cyclin-dependent kinase 5 (CDK5).
  • The study utilized various scientific methods to analyze how 5-HT7R interacts with CDK5, discovering that specific regions of 5-HT7R are crucial for this interaction and identifying key phenylalanine residues that impact complex formation.
  • The findings suggest that targeting the interaction between 5-HT7R and CDK5 could lead to new treatments for diseases related to Tau aggregation, offering a potential pathway for drug development.
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Acute myocardial infarction (AMI) is one of the leading causes of death worldwide and treatment costs pose a major burden on the global health care system. Despite the variety of treatment options, individual recovery can be still poor and the mortality rate, especially in the first few years after the event, remains high. Therefore, intense research is currently focused on identifying novel target molecules to improve the outcome following AMI.

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Hypertrophic cardiomyopathy (HCM) is the most prevalent inherited cardiac disease. Up to 40% of cases are associated with heterozygous mutations in myosin binding protein C (cMyBP-C, MYBPC3). Most of these mutations lead to premature termination codons (PTC) and patients show reduction of functional cMyBP-C.

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Introduction: Hyperphosphorylation and aggregation of the microtubule-associated protein tau cause the development of tauopathies, such as Alzheimer's disease and frontotemporal dementia (FTD). We recently uncovered a causal link between constitutive serotonin receptor 7 (5-HT7R) activity and pathological tau aggregation. Here, we evaluated 5-HT7R inverse agonists as novel drugs in the treatment of tauopathies.

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The protein cell division cycle 42 (Cdc42) is a small GTPase of the Rho family regulating a plethora of physiological functions in a tissue, cell and subcellular-specific manner participating in multiple signaling pathways. Since the corresponding signaling hubs are mainly organized along the cellular membranes, cytosolic proteins like Cdc42 need to be properly targeted and held at the membrane. Here, lipid modifications come into play: Cdc42 can be associated with membranes by different lipid anchors including prenylation (Cdc42-prenyl) and palmitoylation (Cdc42-palm).

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Structural changes of astrocytes and their perisynaptic processes occur in response to various physiological and pathophysiological stimuli. They are thought to profoundly affect synaptic signalling and neuron-astrocyte communication. Understanding the causal relationship between astrocyte morphology changes and their functional consequences requires experimental tools to selectively manipulate astrocyte morphology.

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Serotonin receptor 5-HT and tropomyosin receptor kinase B (TrkB) strongly contribute to neuroplasticity regulation and are implicated in numerous neuronal disorders. Here, we demonstrate a physical interaction between 5-HT and TrkB in vitro and in vivo using co-immunoprecipitation and biophysical and biochemical approaches. Heterodimerization decreased TrkB autophosphorylation, preventing its activation with agonist 7,8-DHF, even with low 5-HT receptor expression.

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Members of the regulatory Kvβ family modulate the kinetics and traffic of voltage-dependent K (Kv) channels. The crystal structure of Kv channels associated with Kvβ peptides suggests a α4/β4 composition. Although Kvβ2 and Kvβ1 form heteromers, evidence supports that only Kvβ2.

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The tolerance of amino acid starvation is fundamental to robust cellular fitness. Asparagine depletion is lethal to some cancer cells, a vulnerability that can be exploited clinically. We report that resistance to asparagine starvation is uniquely dependent on an N-terminal low-complexity domain of GSK3α, which its paralog GSK3β lacks.

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Aim: A high-fat diet (HFD) is generally considered to negatively influence the body, the brain, and cognition. Nonetheless, fat and fatty acids are essential for nourishing and constructing brain tissue. Astrocytes are central for lipolysis and fatty acids metabolism.

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Article Synopsis
  • The small GTPase Cdc42 has two variants: the common Cdc42-prenyl and the brain-specific Cdc42-palm, which can be modified through palmitoylation at specific cysteine residues.
  • The study reveals that only a small amount of Cdc42 experiences palmitoylation in certain cells, and identifies DHHC5 as a key enzyme that interacts with and regulates the palmitoylation of Cdc42-palm.
  • Disruption of DHHC5 function leads to decreased palmitoylation and affects Cdc42's role in gene transcription and neuron structure, highlighting the importance of DHHC5 in Cdc42 regulation within the brain.
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Major depressive disorder is a complex disease resulting from aberrant synaptic plasticity that may be caused by abnormal serotonergic signaling. Using a combination of behavioral, biochemical, and imaging methods, we analyze 5-HT7R/MMP-9 signaling and dendritic spine plasticity in the hippocampus in mice treated with the selective 5-HT7R agonist (LP-211) and in a model of chronic unpredictable stress (CUS)-induced depressive-like behavior. We show that acute 5-HT7R activation induces depressive-like behavior in mice in an MMP-9-dependent manner and that post mortem brain samples from human individuals with depression reveal increased MMP-9 enzymatic activity in the hippocampus.

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Three-dimensional segmentation and analysis of dendritic spine morphology involve two major challenges: 1) how to segment individual spines from the dendrites and 2) how to quantitatively assess the morphology of individual spines. To address these two issues, we developed software called 3dSpAn (3-dimensional Spine Analysis), based on implementing a previously published method, 3D multi-scale opening algorithm in shared intensity space. 3dSpAn consists of four modules: a) Preprocessing and Region of Interest (ROI) selection, b) Intensity thresholding and seed selection, c) Multi-scale segmentation, and d) Quantitative morphological feature extraction.

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