Structural properties and role of the endocannabinoid lipases ABHD6 and ABHD12 in lipid signalling and disease

Tuning almond lipase features by the buffer used during immobilization: The apparent biocatalysts stability depends on the immobilization and inactivation buffers and the substrate utilized

The lipase from Prunus dulcis almonds was inactivated under different conditions. At pH 5 and 9, enzyme stability remained similar under the different studied buffers. However, when the inactivation was performed at pH 7, there were some clear differences on enzyme stability depending on the buffer used. The enzyme was more stable in Gly than when Tris was employed for inactivation. Then, the enzyme was immobilized on methacrylate beads coated with octadecyl groups at pH 7 in the presence of Gly, Tris, phosphate and HEPES. Its activity was assayed versus triacetin and S-methyl mandelate. The biocatalyst prepared in phosphate was more active versus S-methyl mandelate, while the other ones were more active versus triacetin. The immobilized enzyme stability at pH 7 depends on the buffer used for enzyme immobilization. The buffer used in the inactivation and the substrate used determined the activity. For example, glycine was the buffer that promoted the lowest or the highest stabilities depending on the substrate used to quantify the activities.

Lysophosphatidylserine: A Signaling Lipid with Implications in Human Diseases

Lysophosphatidylserine (lyso-PS) has emerged as yet another important signaling lysophospholipid in mammals, and deregulation in its metabolism has been directly linked to an array of human autoimmune and neurological disorders. It has an indispensable role in several biological processes in humans, and therefore, cellular concentrations of lyso-PS are tightly regulated to ensure optimal signaling and functioning in physiological settings. Given its biological importance, the past two decades have seen an explosion in the available literature toward our understanding of diverse aspects of lyso-PS metabolism and signaling and its association with human diseases. In this Review, we aim to comprehensively summarize different aspects of lyso-PS, such as its structure, biodistribution, chemical synthesis, and SAR studies with some synthetic analogs. From a biochemical perspective, we provide an exhaustive coverage of the diverse biological activities modulated by lyso-PSs, such as its metabolism and the receptors that respond to them in humans. We also briefly discuss the human diseases associated with aberrant lyso-PS metabolism and signaling and posit some future directions that may advance our understanding of lyso-PS-mediated mammalian physiology.

ABHD12 contributes to tumorigenesis and sorafenib resistance by preventing ferroptosis in hepatocellular carcinoma

Sorafenib induces ferroptosis, making it a useful treatment against advanced liver hepatocellular carcinoma (LIHC). However, sorafenib resistance is extremely common among LIHC patients. Here, we used a comprehensive approach to investigate the effects of ABHD12, which regulates tumorigenesis and sorafenib resistance in LIHC. We validated ABHD12 expression was upregulated in LIHC tissue, which correlated with worse overall survival and related to tumor size or stage. ABHD12 facilitated a pro-tumorigenic phenotype involving increased cell proliferation, migration, and clonogenicity as well as sorafenib resistance. Knockout of ABHD12 sensitized liver cancer cells to sorafenib-induced ferroptosis. Co-delivery of sorafenib and ABHD12 inhibitor into a nude mouse model enhanced therapeutic efficacy for LIHC. Our study demonstrates that ABHD12 contributes to tumor growth and sorafenib resistance in liver cancer, which indicate the promising potential of ABHD12 in diagnosis and prognosis as well as highlight the potential therapeutic applications for co-delivery of sorafenib and ABHD12 inhibitor.

Utilizing PET and MALDI Imaging for Discovery of a Targeted Probe for Brain Endocannabinoid α/β-Hydrolase Domain 6 (ABHD6)

Multimodal imaging provides rich biological information, which can be exploited to study drug activity, disease associated phenotypes, and pharmacological responses. Here we show discovery and validation of a new probe targeting the endocannabinoid α/β-hydrolase domain 6 (ABHD6) enzyme by utilizing positron emission tomography (PET) and matrix-assisted laser desorption/ionization (MALDI) imaging. [¹⁸F]JZP-MA-11 as the first PET ligand for in vivo imaging of the ABHD6 is reported and specific uptake in ABHD6-rich peripheral tissues and major brain regions was demonstrated using PET. A proof-of-concept study in nonhuman primate confirmed brain uptake. In vivo pharmacological response upon ABHD6 inhibition was observed by MALDI imaging. These synergistic imaging efforts used to identify biological information cannot be obtained by a single imaging modality and hold promise for improving the understanding of ABHD6-mediated endocannabinoid metabolism in peripheral and central nervous system disorders.

α/β-Hydrolase Domain-Containing 6 (ABHD6)- A Multifunctional Lipid Hydrolase

α/β-hydrolase domain-containing 6 (ABHD6) belongs to the α/β-hydrolase fold superfamily and was originally discovered in a functional proteomic approach designed to discover monoacylglycerol (MAG) hydrolases in the mouse brain degrading the endocannabinoid 2-arachidonoylglycerol. Subsequent studies confirmed that ABHD6 acts as an MAG hydrolase regulating cannabinoid receptor-dependent and -independent signaling processes. The enzyme was identified as a negative modulator of insulin secretion and regulator of energy metabolism affecting the pathogenesis of obesity and metabolic syndrome. It has been implicated in the metabolism of the lysosomal co-factor bis(monoacylglycerol)phosphate and in the surface delivery of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid-type glutamate receptors. Finally, ABHD6 was shown to affect cancer cell lipid metabolism and tumor malignancy. Here, we provide new insights into the experimentally derived crystal structure of ABHD6 and its possible orientation in biological membranes, and discuss ABHD6's functions in health and disease.

A review on structurally diversified synthesized molecules as monoacylglycerol lipase inhibitors and their therapeutic uses

Monoacylglycerol is a metabolic key serine hydrolase, engaged in the regulation of signalling network system of endocannabinoids, which is associated with various physiological processes like pain, inflammation, feeding cognition and neurodegenerative diseases like Alzheimer, Parkinson's disease. The monoacylglycerol also found to act as a regulator and the free fatty acid provider in the proliferation of cancer cells, numerous aggressive tumours such as colorectal cancer, neuroblastoma and nasopharyngeal carcinoma. It also played an important role in increasing the concentration of specific lipids derived from free fatty acids like phosphatidic acid, lysophosphatidic acid, sphingosine-1-phosphate and prostaglandin E2. These signalling lipids are associated with cell proliferation, survival, tumour cell migration, contributing to tumour development, maturation and metastases. In the present study here, we are presenting a review on structurally diverse MAGL inhibitors, their development and their evaluation for different pharmacological activities.

Alpha/Beta-Hydrolase Domain-Containing 6: Signaling and Function in the Central Nervous System

Endocannabinoid (eCB) signaling plays an important role in the central nervous system (CNS). α/β-Hydrolase domain-containing 6 (ABHD6) is a transmembrane serine hydrolase that hydrolyzes monoacylglycerol (MAG) lipids such as endocannabinoid 2-arachidonoyl glycerol (2-AG). ABHD6 participates in neurotransmission, inflammation, brain energy metabolism, tumorigenesis and other biological processes and is a potential therapeutic target for various neurological diseases, such as traumatic brain injury (TBI), multiple sclerosis (MS), epilepsy, mental illness, and pain. This review summarizes the molecular mechanisms of action and biological functions of ABHD6, particularly its mechanism of action in the pathogenesis of neurological diseases, and provides a theoretical basis for new pharmacological interventions via targeting of ABHD6.

α/β-Hydrolase Domain (ABHD) Inhibitors as New Potential Therapeutic Options against Lipid-Related Diseases

Much of the experimental evidence in the literature has linked altered lipid metabolism to severe diseases such as cancer, obesity, cardiovascular pathologies, diabetes, and neurodegenerative diseases. Therefore, targeting key effectors of the dysregulated lipid metabolism may represent an effective strategy to counteract these pathological conditions. In this context, α/β-hydrolase domain (ABHD) enzymes represent an important and diversified family of proteins, which are involved in the complex environment of lipid signaling, metabolism, and regulation. Moreover, some members of the ABHD family play an important role in the endocannabinoid system, being designated to terminate the signaling of the key endocannabinoid regulator 2-arachidonoylglycerol. This Perspective summarizes the research progress in the development of ABHD inhibitors and modulators: design strategies, structure-activity relationships, action mechanisms, and biological studies of the main ABHD ligands will be highlighted.

Human Interferon Inducible Transmembrane Protein 3 (IFITM3) Inhibits Influenza Virus A Replication and Inflammation by Interacting with ABHD16A

Studies have shown that human interferon inducible transmembrane protein (hIFITMs) family proteins have broad-spectrum antiviral capabilities. Preliminary studies in our laboratory have tentatively proved that hIFITMs have the effect of inhibiting influenza viruses. In order to further study its mechanism and role in the occurrence and development of influenza A, relevant studies have been carried out. Fluorescence quantitative polymerase chain reaction (PCR) detection technology was used to observe the effect of hIFITM3 on the replication of influenza A virus (IVA) and the interaction with hABHD16A. In HEK293 cells, overexpression of hIFITM3 protein significantly inhibited the replication of IVA at 24 h, 48 h, and 72 h; yeast two-hybrid experiment proved that hIFITM3 interacts with hABHD16A; laser confocal microscopy observations showed that hIFITM3 and hABHD16A colocalized in the cell membrane area; the expression level of inflammation-related factors in cells overexpressing hIFITM3 or hABHD16A was detected by fluorescence quantitative PCR, and the results showed that the mRNA levels of interleukin- (IL-) 1β, IL-6, IL-10, tumor necrosis factor- (TNF-) α, and cyclooxygenase 2 (COX2) were significantly increased. But when hIFITM3/hABHD16A was coexpressed, the mRNA expression levels of these cytokines were significantly reduced except COX2. When influenza virus infected cells coexpressing hIFITM3/hABHD16A, the expression level of inflammatory factors decreased compared with the control group, indicating that hIFITM3 can play an important role in regulating inflammation balance. This study confirmed that hIFITM3 has an effect of inhibiting IVA replication. Furthermore, it was found that hIFITM3 interacts with hABHD16A, following which it can better inhibit the replication of influenza virus and the inflammatory response caused by the disease process.

Current Aspects of the Endocannabinoid System and Targeted THC and CBD Phytocannabinoids as Potential Therapeutics for Parkinson's and Alzheimer's Diseases: a Review

Neurodegeneration leading to Parkinson's disease (PD) and Alzheimer's disease (AD) has become a major health burden globally. Current treatments mainly target controlling symptoms and there are no therapeutics available in clinical practice to preventing the neurodegeneration or inducing neuronal repairing. Thus, the demand of novel research for the two disorders is imperative. This literature review aims to provide a collection of published work on PD and AD and current uses of endocannabinoid system (ECS) as a potential drug target for neurodegeneration. PD is frequently treated with L-DOPA and deep brain stimulation. Recent gene modification and remodelling techniques, such as CRISPR through human embryonic stem cells and induced pluripotent stem cells, have shown promising strategy for personalised medicine. AD characterised by extracellular deposits of amyloid β-senile plaques and neurofibrillary tangles of tau protein commonly uses choline acetyltransferase enhancers as therapeutics. The ECS is currently being studied as PD and AD drug targets where overexpression of ECS receptors exerted neuroprotection against PD and reduced neuroinflammation in AD. The delta-9-tetrahydrocannabinoid (Δ9-THC) and cannabidiol (CBD) cannabinoids of plant Cannabis sativa have shown neuroprotection upon PD and AD animal models yet triggered toxic effects on patients when administered directly. Therefore, understanding the precise molecular cascade following cannabinoid treatment is suggested, focusing especially on gene expression to identify drug targets for preventing and repairing neurodegeneration.

Impact of tetrahydrocannabinol on the endocannabinoid 2-arachidonoylglycerol metabolism: ABHD6 and ABHD12 as novel players in human placenta

Cannabis use has been increasing worldwide for recreational and medical purposes. Consumption by pregnant women is associated with disturbances in pregnancy outcome, such as low birth weight, prematurity and intrauterine growth retardation, though the underlying biochemical mechanisms are unknown. The endocannabinoid system is involved in several reproductive events and the disruption of its homeostasis by ∆⁹-tetrahydrocannabinol (THC), the main psychoactive cannabinoid, may lead to a negative gestational outcome. In human placenta, THC impairs the levels of the endocannabinoid anandamide (AEA). The other major endocannabinoid, 2-arachidonoylglycerol (2-AG) also plays an important role on proper placentation and pregnancy success. However, THC impact on 2-AG homeostasis has never been addressed. Hence, the effects of THC in 2-AG levels and metabolic enzymes expression were explored. Long-term treatment impairs the expression of the main 2-AG synthetic and degradative enzymes. Curiously, with the highest concentration, despite the maintenance of diacylglycerol lipase alpha (DAGLα) and the decrease in monoacylglycerol lipase (MAGL) expression, 2-AG levels remain constant. Given the endocannabinoid signalling local tight regulation, we hypothesize the involvement of other 2-AG degradative enzymes. Indeed, THC increases the expression of the hydrolyzing enzymes alpha beta hydrolase domain-6 (ABHD6) and -12 (ABHD12), that we firstly describe in human placental tissues. The results show that THC, depending on time of exposure, induces alterations in 2-AG metabolic enzymes expression in placental explants, highlighting the importance of 2-AG regulation and endocannabinoid signalling in placental development. Alterations in this homeostasis may explain the negative pregnancy outcome related to cannabis consumption.

A Guide to Targeting the Endocannabinoid System in Drug Design

The endocannabinoid system (ECS) is one of the most crucial systems in the human organism, exhibiting multi-purpose regulatory character. It is engaged in a vast array of physiological processes, including nociception, mood regulation, cognitive functions, neurogenesis and neuroprotection, appetite, lipid metabolism, as well as cell growth and proliferation. Thus, ECS proteins, including cannabinoid receptors and their endogenous ligands’ synthesizing and degrading enzymes, are promising therapeutic targets. Their modulation has been employed in or extensively studied as a treatment of multiple diseases. However, due to a complex nature of ECS and its crosstalk with other biological systems, the development of novel drugs turned out to be a challenging task. In this review, we summarize potential therapeutic applications for ECS-targeting drugs, especially focusing on promising synthetic compounds and preclinical studies. We put emphasis on modulation of specific proteins of ECS in different pathophysiological areas. In addition, we stress possible difficulties and risks and highlight proposed solutions. By presenting this review, we point out information pivotal in the spotlight of ECS-targeting drug design, as well as provide an overview of the current state of knowledge on ECS-related pharmacodynamics and show possible directions for needed research.