Protocols for Enzymatic Fluorometric Assays to Quantify Phospholipid Classes

Phospholipids, consisting of a hydrophilic head group and two hydrophobic acyl chains, are essential for the structures of cell membranes, plasma lipoproteins, biliary mixed micelles, pulmonary surfactants, and extracellular vesicles. Beyond their structural roles, phospholipids have important roles in numerous biological processes. Thus, abnormalities in the metabolism and transport of phospholipids are involved in many diseases, including dyslipidemia, atherosclerosis, cholestasis, drug-induced liver injury, neurological diseases, autoimmune diseases, respiratory diseases, myopathies, and cancers. To further clarify the physiological, pathological, and molecular mechanisms and to identify disease biomarkers, we have recently developed enzymatic fluorometric assays for quantifying all major phospholipid classes, phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidic acid, phosphatidylinositol, phosphatidylglycerol + cardiolipin, and sphingomyelin. These assays are specific, sensitive, simple, and high-throughput, and will be applicable to cells, intracellular organelles, tissues, fluids, lipoproteins, and extracellular vesicles. In this review, we present the detailed protocols for the enzymatic fluorometric measurements of phospholipid classes in cultured cells.

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A Mucin-Specific Protease Enables Molecular and Functional Analysis of Human Cancer-Associated Mucins

10.26434/chemrxiv.7330676 ◽

2018 ◽

Author(s):

Stacy A. Malaker ◽

Kayvon Pedram ◽

Michael J. Ferracane ◽

Elliot C. Woods ◽

Jessica Kramer ◽

...

Keyword(s):

Mass Spectrometry ◽

Molecular Mechanisms ◽

Cultured Cells ◽

High Resolution Mass Spectrometry ◽

Human Cancer ◽

Glycosylation Sites ◽

Bacterial Protease ◽

Specific Protease ◽

To Come ◽

And Function

<div> <div> <div> <p>Mucins are a class of highly O-glycosylated proteins that are ubiquitously expressed on cellular surfaces and are important for human health, especially in the context of carcinomas. However, the molecular mechanisms by which aberrant mucin structures lead to tumor progression and immune evasion have been slow to come to light, in part because methods for selective mucin degradation are lacking. Here we employ high resolution mass spectrometry, polymer synthesis, and computational peptide docking to demonstrate that a bacterial protease, called StcE, cleaves mucin domains by recognizing a discrete peptide-, glycan-, and secondary structure- based motif. We exploited StcE’s unique properties to map glycosylation sites and structures of purified and recombinant human mucins by mass spectrometry. As well, we found that StcE will digest cancer-associated mucins from cultured cells and from ovarian cancer patient-derived ascites fluid. Finally, using StcE we discovered that Siglec-7, a glyco-immune checkpoint receptor, specifically binds sialomucins as biological ligands, whereas the related Siglec-9 receptor does not. Mucin-specific proteolysis, as exemplified by StcE, is therefore a powerful tool for the study of glycoprotein structure and function and for deorphanizing mucin-binding receptors. </p> </div> </div> </div>

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Role of Long Non-Coding RNA Polymorphisms in Cancer Chemotherapeutic Response

Journal of Personalized Medicine ◽

10.3390/jpm11060513 ◽

2021 ◽

Vol 11 (6) ◽

pp. 513

Author(s):

Zheng Zhang ◽

Meng Gu ◽

Zhongze Gu ◽

Yan-Ru Lou

Keyword(s):

Molecular Mechanisms ◽

Neurological Diseases ◽

Cellular Processes ◽

Dna And Rna ◽

Chemotherapeutic Response ◽

Non Coding Rna ◽

Response To Chemotherapy ◽

Personalized Oncology ◽

Long Non Coding Rna

Genetic polymorphisms are defined as the presence of two or more different alleles in the same locus, with a frequency higher than 1% in the population. Since the discovery of long non-coding RNAs (lncRNAs), which refer to a non-coding RNA with a length of more than 200 nucleotides, their biological roles have been increasingly revealed in recent years. They regulate many cellular processes, from pluripotency to cancer. Interestingly, abnormal expression or dysfunction of lncRNAs is closely related to the occurrence of human diseases, including cancer and degenerative neurological diseases. Particularly, their polymorphisms have been found to be associated with altered drug response and/or drug toxicity in cancer treatment. However, molecular mechanisms are not yet fully elucidated, which are expected to be discovered by detailed studies of RNA–protein, RNA–DNA, and RNA–lipid interactions. In conclusion, lncRNAs polymorphisms may become biomarkers for predicting the response to chemotherapy in cancer patients. Here we review and discuss how gene polymorphisms of lncRNAs affect cancer chemotherapeutic response. This knowledge may pave the way to personalized oncology treatments.

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Inactivation of EMILIN-1 by Proteolysis and Secretion in Small Extracellular Vesicles Favors Melanoma Progression and Metastasis

International Journal of Molecular Sciences ◽

10.3390/ijms22147406 ◽

2021 ◽

Vol 22 (14) ◽

pp. 7406

Author(s):

Ana Amor López ◽

Marina S. Mazariegos ◽

Alessandra Capuano ◽

Pilar Ximénez-Embún ◽

Marta Hergueta-Redondo ◽

...

Keyword(s):

Lymph Node ◽

Lymph Node Metastasis ◽

Cell Viability ◽

Extracellular Vesicles ◽

Primary Tumor ◽

Molecular Mechanisms ◽

Primary Tumor Growth ◽

Node Metastasis ◽

Metastatic Cells ◽

Tumor Growth And Metastasis

Several studies have demonstrated that melanoma-derived extracellular vesicles (EVs) are involved in lymph node metastasis; however, the molecular mechanisms involved are not completely defined. Here, we found that EMILIN-1 is proteolyzed and secreted in small EVs (sEVs) as a novel mechanism to reduce its intracellular levels favoring metastasis in mouse melanoma lymph node metastatic cells. Interestingly, we observed that EMILIN-1 has intrinsic tumor and metastasis suppressive-like properties reducing effective migration, cell viability, primary tumor growth, and metastasis. Overall, our analysis suggests that the inactivation of EMILIN-1 by proteolysis and secretion in sEVs reduce its intrinsic tumor suppressive activities in melanoma favoring tumor progression and metastasis.

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Molecular mechanisms of metabotropic GABAB receptor function

Science Advances ◽

10.1126/sciadv.abg3362 ◽

2021 ◽

Vol 7 (22) ◽

pp. eabg3362

Author(s):

Hamidreza Shaye ◽

Benjamin Stauch ◽

Cornelius Gati ◽

Vadim Cherezov

Keyword(s):

G Protein ◽

Molecular Mechanisms ◽

Gabab Receptor ◽

Neurological Diseases ◽

Activation Mechanism ◽

Allosteric Modulators ◽

Inhibitory Neurotransmitter ◽

Therapeutic Drugs ◽

G Protein Coupled ◽

The Brain

Metabotropic γ-aminobutyric acid G protein–coupled receptors (GABAB) represent one of the two main types of inhibitory neurotransmitter receptors in the brain. These receptors act both pre- and postsynaptically by modulating the transmission of neuronal signals and are involved in a range of neurological diseases, from alcohol addiction to epilepsy. A series of recent cryo-EM studies revealed critical details of the activation mechanism of GABAB. Structures are now available for the receptor bound to ligands with different modes of action, including antagonists, agonists, and positive allosteric modulators, and captured in different conformational states from the inactive apo to the fully active state bound to a G protein. These discoveries provide comprehensive insights into the activation of the GABAB receptor, which not only broaden our understanding of its structure, pharmacology, and physiological effects but also will ultimately facilitate the discovery of new therapeutic drugs and neuromodulators.

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Mitochondrial Dynamics, ROS, and Cell Signaling: A Blended Overview

Life ◽

10.3390/life11040332 ◽

2021 ◽

Vol 11 (4) ◽

pp. 332

Author(s):

Valentina Brillo ◽

Leonardo Chieregato ◽

Luigi Leanza ◽

Silvia Muccioli ◽

Roberto Costa

Keyword(s):

Molecular Mechanisms ◽

Mitochondrial Dynamics ◽

Eukaryotic Cells ◽

Therapeutic Approaches ◽

Cellular Functions ◽

Lipid Trafficking ◽

Mitochondrial Ros ◽

Intracellular Organelles ◽

Proliferation Regulation ◽

Dynamic Plasticity

Mitochondria are key intracellular organelles involved not only in the metabolic state of the cell, but also in several cellular functions, such as proliferation, Calcium signaling, and lipid trafficking. Indeed, these organelles are characterized by continuous events of fission and fusion which contribute to the dynamic plasticity of their network, also strongly influenced by mitochondrial contacts with other subcellular organelles. Nevertheless, mitochondria release a major amount of reactive oxygen species (ROS) inside eukaryotic cells, which are reported to mediate a plethora of both physiological and pathological cellular functions, such as growth and proliferation, regulation of autophagy, apoptosis, and metastasis. Therefore, targeting mitochondrial ROS could be a promising strategy to overcome and hinder the development of diseases such as cancer, where malignant cells, possessing a higher amount of ROS with respect to healthy ones, could be specifically targeted by therapeutic treatments. In this review, we collected the ultimate findings on the blended interplay among mitochondrial shaping, mitochondrial ROS, and several signaling pathways, in order to contribute to the dissection of intracellular molecular mechanisms involved in the pathophysiology of eukaryotic cells, possibly improving future therapeutic approaches.

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Molecular mechanisms of cell death in neurological diseases

Cell Death and Differentiation ◽

10.1038/s41418-021-00814-y ◽

2021 ◽

Author(s):

Diane Moujalled ◽

Andreas Strasser ◽

Jeffrey R. Liddell

Keyword(s):

Cell Death ◽

Neurodegenerative Diseases ◽

Molecular Mechanisms ◽

Neuronal Development ◽

Neurological Diseases ◽

Treatment Strategies ◽

Current Treatment ◽

Response To Therapy ◽

Signalling Cascades ◽

The Brain

AbstractTightly orchestrated programmed cell death (PCD) signalling events occur during normal neuronal development in a spatially and temporally restricted manner to establish the neural architecture and shaping the CNS. Abnormalities in PCD signalling cascades, such as apoptosis, necroptosis, pyroptosis, ferroptosis, and cell death associated with autophagy as well as in unprogrammed necrosis can be observed in the pathogenesis of various neurological diseases. These cell deaths can be activated in response to various forms of cellular stress (exerted by intracellular or extracellular stimuli) and inflammatory processes. Aberrant activation of PCD pathways is a common feature in neurodegenerative diseases, such as amyotrophic lateral sclerosis (ALS), Alzheimer’s disease, Parkinson’s disease, and Huntington’s disease, resulting in unwanted loss of neuronal cells and function. Conversely, inactivation of PCD is thought to contribute to the development of brain cancers and to impact their response to therapy. For many neurodegenerative diseases and brain cancers current treatment strategies have only modest effect, engendering the need for investigations into the origins of these diseases. With many diseases of the brain displaying aberrations in PCD pathways, it appears that agents that can either inhibit or induce PCD may be critical components of future therapeutic strategies. The development of such therapies will have to be guided by preclinical studies in animal models that faithfully mimic the human disease. In this review, we briefly describe PCD and unprogrammed cell death processes and the roles they play in contributing to neurodegenerative diseases or tumorigenesis in the brain. We also discuss the interplay between distinct cell death signalling cascades and disease pathogenesis and describe pharmacological agents targeting key players in the cell death signalling pathways that have progressed through to clinical trials.

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Mitochondrial Dynamics in Drug-Induced Liver Injury

Livers ◽

10.3390/livers1030010 ◽

2021 ◽

Vol 1 (3) ◽

pp. 102-115

Author(s):

Anup Ramachandran ◽

David S. Umbaugh ◽

Hartmut Jaeschke

Keyword(s):

Liver Injury ◽

Molecular Mechanisms ◽

Membrane Lipids ◽

Mitochondrial Dynamics ◽

Adaptive Responses ◽

Drug Induced ◽

Biologically Relevant ◽

Drug Induced Liver Injury ◽

Relevant Role ◽

Atp Generation

Mitochondria have been studied for decades from the standpoint of metabolism and ATP generation. However, in recent years mitochondrial dynamics and its influence on bioenergetics and cellular homeostasis is also being appreciated. Mitochondria undergo regular cycles of fusion and fission regulated by various cues including cellular energy requirements and pathophysiological stimuli, and the network of critical proteins and membrane lipids involved in mitochondrial dynamics is being revealed. Hepatocytes are highly metabolic cells which have abundant mitochondria suggesting a biologically relevant role for mitochondrial dynamics in hepatocyte injury and recovery. Here we review information on molecular mediators of mitochondrial dynamics and their alteration in drug-induced liver injury. Based on current information, it is evident that changes in mitochondrial fusion and fission are hallmarks of liver pathophysiology ranging from acetaminophen-induced or cholestatic liver injury to chronic liver diseases. These alterations in mitochondrial dynamics influence multiple related mitochondrial responses such as mitophagy and mitochondrial biogenesis, which are important adaptive responses facilitating liver recovery in several contexts, including drug-induced liver injury. The current focus on characterization of molecular mechanisms of mitochondrial dynamics is of immense relevance to liver pathophysiology and have the potential to provide significant insight into mechanisms of liver recovery and regeneration after injury.

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The Emerging Role of Extracellular Vesicles in Endocrine Resistant Breast Cancer

Cancers ◽

10.3390/cancers13051160 ◽

2021 ◽

Vol 13 (5) ◽

pp. 1160

Author(s):

Giusi La Camera ◽

Luca Gelsomino ◽

Amanda Caruso ◽

Salvatore Panza ◽

Ines Barone ◽

...

Keyword(s):

Breast Cancer ◽

Endocrine Therapy ◽

Extracellular Vesicles ◽

Molecular Mechanisms ◽

Endocrine Resistance ◽

Disease Recurrence ◽

Estrogen Receptor Α ◽

Research Area ◽

Tumor Evolution

Breast cancer is the most common solid malignancy diagnosed in females worldwide, and approximately 70% of these tumors express estrogen receptor α (ERα), the main biomarker of endocrine therapy. Unfortunately, despite the use of long-term anti-hormone adjuvant treatment, which has significantly reduced patient mortality, resistance to the endocrine treatments often develops, leading to disease recurrence and limiting clinical benefits. Emerging evidence indicates that extracellular vesicles (EVs), nanosized particles that are released by all cell types and responsible for local and systemic intercellular communications, might represent a newly identified mechanism underlying endocrine resistance. Unraveling the role of EVs, released by transformed cells during the tumor evolution under endocrine therapy, is still an open question in the cancer research area and the molecular mechanisms involved should be better defined to discover alternative therapeutic approaches to overcome resistance. In this review, we will provide an overview of recent findings on the involvement of EVs in sustaining hormonal resistance in breast cancer and discuss opportunities for their potential use as biomarkers to monitor the therapeutic response and disease progression.

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Monoclonal Antibodies as Neurological Therapeutics

Pharmaceuticals ◽

10.3390/ph14020092 ◽

2021 ◽

Vol 14 (2) ◽

pp. 92

Author(s):

Panagiotis Gklinos ◽

Miranta Papadopoulou ◽

Vid Stanulovic ◽

Dimos D. Mitsikostas ◽

Dimitrios Papadopoulos

Keyword(s):

Monoclonal Antibodies ◽

Molecular Mechanisms ◽

Neurological Diseases ◽

Therapeutic Agents ◽

Medical Specialties ◽

Specific Effects ◽

Different Types ◽

Neurological Conditions ◽

Disease Pathways

Over the last 30 years the role of monoclonal antibodies in therapeutics has increased enormously, revolutionizing treatment in most medical specialties, including neurology. Monoclonal antibodies are key therapeutic agents for several neurological conditions with diverse pathophysiological mechanisms, including multiple sclerosis, migraines and neuromuscular disease. In addition, a great number of monoclonal antibodies against several targets are being investigated for many more neurological diseases, which reflects our advances in understanding the pathogenesis of these diseases. Untangling the molecular mechanisms of disease allows monoclonal antibodies to block disease pathways accurately and efficiently with exceptional target specificity, minimizing non-specific effects. On the other hand, accumulating experience shows that monoclonal antibodies may carry class-specific and target-associated risks. This article provides an overview of different types of monoclonal antibodies and their characteristics and reviews monoclonal antibodies currently in use or under development for neurological disease.

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