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International Journal of Molecular... Jun 2024Connexin hemichannels (HCs) expressed at the plasma membrane of mammalian cells are of paramount importance for intercellular communication. In physiological conditions,... (Review)
Review
Connexin hemichannels (HCs) expressed at the plasma membrane of mammalian cells are of paramount importance for intercellular communication. In physiological conditions, HCs can form gap junction (GJ) channels, providing a direct diffusive path between neighbouring cells. In addition, unpaired HCs provide conduits for the exchange of solutes between the cytoplasm and the extracellular milieu, including messenger molecules involved in paracrine signalling. The synergistic action of membrane potential and Ca ions controls the gating of the large and relatively unselective pore of connexin HCs. The four orders of magnitude difference in gating sensitivity to the extracellular ([Ca]) and the cytosolic ([Ca]) Ca concentrations suggests that at least two different Ca sensors may exist. While [Ca] acts as a spatial modulator of the HC opening, which is most likely dependent on the cell layer, compartment, and organ, [Ca] triggers HC opening and the release of extracellular bursts of messenger molecules. Such molecules include ATP, cAMP, glutamate, NAD, glutathione, D-serine, and prostaglandins. Lost or abnormal HC regulation by Ca has been associated with several diseases, including deafness, keratitis ichthyosis, palmoplantar keratoderma, Charcot-Marie-Tooth neuropathy, oculodentodigital dysplasia, and congenital cataracts. The fact that both an increased and a decreased Ca sensitivity has been linked to pathological conditions suggests that Ca in healthy cells finely tunes the normal HC function. Overall, further investigation is needed to clarify the structural and chemical modifications of connexin HCs during [Ca] and [Ca] variations. A molecular model that accounts for changes in both Ca and the transmembrane voltage will undoubtedly enhance our interpretation of the experimental results and pave the way for developing therapeutic compounds targeting specific HC dysfunctions.
Topics: Connexins; Humans; Calcium; Animals; Gap Junctions; Calcium Signaling
PubMed: 38928300
DOI: 10.3390/ijms25126594 -
JHEP Reports : Innovation in Hepatology Aug 2023Liver regeneration is a repair process in which metabolic reprogramming of parenchymal and inflammatory cells plays a major role. Monoacylglycerol lipase (MAGL) is an...
BACKGROUND & AIMS
Liver regeneration is a repair process in which metabolic reprogramming of parenchymal and inflammatory cells plays a major role. Monoacylglycerol lipase (MAGL) is an ubiquitous enzyme at the crossroad between lipid metabolism and inflammation. It converts monoacylglycerols into free fatty acids and metabolises 2-arachidonoylglycerol into arachidonic acid, being thus the major source of pro-inflammatory prostaglandins in the liver. In this study, we investigated the role of MAGL in liver regeneration.
METHODS
Hepatocyte proliferation was studied in hepatoma cell lines and in precision-cut human liver slices. Liver regeneration was investigated in mice treated with a pharmacological MAGL inhibitor, MJN110, as well as in animals globally invalidated for MAGL (MAGL) and specifically invalidated in hepatocytes (MAGL) or myeloid cells (MAGL). Two models of liver regeneration were used: acute toxic carbon tetrachloride injection and two-thirds partial hepatectomy. MAGL liver macrophages profiling was analysed by RNA sequencing. A rescue experiment was performed by administration of interferon receptor antibody in MAGL mice.
RESULTS
Precision-cut human liver slices from patients with chronic liver disease and human hepatocyte cell lines exposed to MJN110 showed reduced hepatocyte proliferation. Mice with global invalidation or mice treated with MJN110 showed blunted liver regeneration. Moreover, mice with specific deletion of MAGL in either hepatocytes or myeloid cells displayed delayed liver regeneration. Mechanistically, MAGL mice showed reduced liver eicosanoid production, in particular prostaglandin E that negatively impacts on hepatocyte proliferation. MAGL inhibition in macrophages resulted in the induction of the type I interferon pathway. Importantly, neutralising the type I interferon pathway restored liver regeneration of MAGL mice.
CONCLUSIONS
Our data demonstrate that MAGL promotes liver regeneration by hepatocyte and macrophage reprogramming.
IMPACT AND IMPLICATIONS
By using human liver samples and mouse models of global or specific cell type invalidation, we show that the monoacylglycerol pathway plays an essential role in liver regeneration. We unveil the mechanisms by which MAGL expressed in both hepatocytes and macrophages impacts the liver regeneration process, via eicosanoid production by hepatocytes and the modulation of the macrophage interferon pathway profile that restrains hepatocyte proliferation.
PubMed: 37520673
DOI: 10.1016/j.jhepr.2023.100794 -
Metabolism, fibrosis, and apoptosis: The effect of lipids and their derivatives on keloid formation.International Wound Journal Feb 2024Keloids, pathological scars resulting from skin trauma, have traditionally posed significant clinical management challenges due to their persistence and high recurrence... (Review)
Review
Keloids, pathological scars resulting from skin trauma, have traditionally posed significant clinical management challenges due to their persistence and high recurrence rates. Our research elucidates the pivotal roles of lipids and their derivatives in keloid development, driven by underlying mechanisms of abnormal cell proliferation, apoptosis, and extracellular matrix deposition. Key findings suggest that abnormalities in arachidonic acid (AA) synthesis and non-essential fatty acid synthesis are integral to keloid formation. Further, a complex interplay exists between lipid derivatives, notably butyric acid (BA), prostaglandin E2 (PGE2), prostaglandin D2 (PGD2), and the regulation of hyperfibrosis. Additionally, combinations of docosahexaenoic acid (DHA) with BA and 15-deoxy-Δ12,14-Prostaglandin J2 have exhibited pronounced cytotoxic effects. Among sphingolipids, ceramide (Cer) displayed limited pro-apoptotic effects in keloid fibroblasts (KFBs), whereas sphingosine 1-phosphate (S1P) was found to promote keloid hyperfibrosis, with its analogue, FTY720, demonstrating contrasting benefits. Both Vitamin D and hexadecylphosphorylcholine (HePC) showed potential antifibrotic and antiproliferative properties, suggesting their utility in keloid management. While keloids remain a prevalent concern in clinical practice, this study underscores the promising potential of targeting specific lipid molecules for the advancement of keloid therapeutic strategies.
Topics: Humans; Keloid; Extracellular Matrix; Fibrosis; Apoptosis; Lipids; Fibroblasts
PubMed: 38339798
DOI: 10.1111/iwj.14733 -
Frontiers in Endocrinology 2023Preterm birth is one of the major causes of neonatal morbidity and mortality across the world. Both term and preterm labour are preceded by inflammatory activation in...
INTRODUCTION
Preterm birth is one of the major causes of neonatal morbidity and mortality across the world. Both term and preterm labour are preceded by inflammatory activation in uterine tissues. This includes increased leukocyte infiltration, and subsequent increase in chemokine and cytokine levels, activation of pro-inflammatory transcription factors as NF-κB and increased prostaglandin synthesis. Prostaglandin F2α (PGF2α) is one of the myometrial activators and stimulators.
METHODS
Here we investigated the role of PGF2α in pro-inflammatory signalling pathways in human myometrial cells isolated from term non-labouring uterine tissue. Primary myometrial cells were treated with G protein inhibitors, calcium chelators and/or PGF2α. Nuclear extracts were analysed by TranSignal cAMP/Calcium Protein/DNA Array. Whole cell protein lysates were analysed by Western blotting. mRNA levels of target genes were analysed by RT-PCR.
RESULTS
The results show that PGF2α increases inflammation in myometrial cells through increased activation of NF-κB and MAP kinases and increased expression of COX-2. PGF2α was found to activate several calcium/cAMP-dependent transcription factors, such as CREB and C/EBP-β. mRNA levels of NF-κB-regulated cytokines and chemokines were also elevated with PGF2α stimulation. We have shown that the increase in PGF2α-mediated COX-2 expression in myometrial cells requires coupling of the FP receptor to both Gαq and Gαi proteins. Additionally, PGF2α-induced calcium response was also mediated through Gαq and Gαi coupling.
DISCUSSION
In summary, our findings suggest that PGF2α-induced inflammation in myometrial cells involves activation of several transcription factors - NF-κB, MAP kinases, CREB and C/EBP-β. Our results indicate that the FP receptor signals via Gαq and Gαi coupling in myometrium. This work provides insight into PGF2α pro-inflammatory signalling in term myometrium prior to the onset of labour and suggests that PGF2α signalling pathways could be a potential target for management of preterm labour.
Topics: Infant, Newborn; Female; Humans; Dinoprost; NF-kappa B; Calcium; Premature Birth; Cyclooxygenase 2; Myometrium; Inflammation; Obstetric Labor, Premature; Cytokines; RNA, Messenger
PubMed: 37547305
DOI: 10.3389/fendo.2023.1150125 -
Frontiers in Endocrinology 2024
Topics: Receptors, G-Protein-Coupled; Signal Transduction
PubMed: 38425756
DOI: 10.3389/fendo.2024.1379108 -
International Journal of Molecular... Aug 2023The ECM propagates processes in idiopathic pulmonary fibrosis (IPF), leading to progressive lung scarring. We established an IPF-conditioned matrix (IPF-CM) system as a... (Review)
Review
The ECM propagates processes in idiopathic pulmonary fibrosis (IPF), leading to progressive lung scarring. We established an IPF-conditioned matrix (IPF-CM) system as a platform for testing drug candidates. Here, we tested the involvement of a PGE2 and PDE4 inhibitor, Roflumilast, in the IPF-CM system. Primary normal/IPF tissue-derived human lung fibroblasts (N/IPF-HLFs) were cultured on Matrigel and then removed to create the IPF-CM. N-HLFs were exposed to the IPF-CM/N-CM with/without PGE2 (1 nM) and Roflumilast (1 µM) for 24 h. The effect of the IPF-CM on cell phenotype and pro-fibrotic gene expression was tested. In addition, electronic records of 107 patients with up to 15-year follow-up were retrospectively reviewed. Patients were defined as slow/rapid progressors using forced vital capacity (FVC) annual decline. Medication exposure was examined. N-HLFs cultured on IPF-CM were arranged in large aggregates as a result of increased proliferation, migration and differentiation. A PGE2 and Roflumilast combination blocked the large aggregate formation induced by the IPF-CM ( < 0.001) as well as cell migration, proliferation, and pro-fibrotic gene expression. A review of patient records showed that significantly more slow-progressing patients were exposed to NSAIDs ( = 0.003). PGE2/PDE4 signaling may be involved in IPF progression. These findings should be further studied.
Topics: Humans; Dinoprostone; Retrospective Studies; Cells, Cultured; Idiopathic Pulmonary Fibrosis; Lung; Fibroblasts; Fibrosis
PubMed: 37569768
DOI: 10.3390/ijms241512393 -
Biomedicine & Pharmacotherapy =... Jul 2023Thromboxane (TX) and prostaglandins are metabolites of arachidonic acid, a twenty-carbon unsaturated fatty acid, and have a variety of actions that are exerted via... (Review)
Review
Thromboxane (TX) and prostaglandins are metabolites of arachidonic acid, a twenty-carbon unsaturated fatty acid, and have a variety of actions that are exerted via specific receptors. Angiogenesis is defined as the formation of new blood vessels from pre-existing vascular beds and is a critical component of pathological conditions, including inflammation and cancer. Lymphatic vessels play crucial roles in the regulation of interstitial fluid, immune surveillance, and the absorption of dietary fat from the intestine; and they are also involved in the pathogenesis of various diseases. Similar to angiogenesis, lymphangiogenesis, the formation of new lymphatic vessels, is a critical component of pathological conditions. The TP-dependent accumulation of platelets in microvessels has been reported to enhance angiogenesis under pathological conditions. Although the roles of some growth factors and cytokines in angiogenesis and lymphangiogenesis have been well characterized, accumulating evidence suggests that TX induces the production of proangiogenic and prolymphangiogenic factors through the activation of adenylate cyclase, and upregulates angiogenesis and lymphangiogenesis under disease conditions. In this review, we discuss the role of TX as a regulator of angiogenesis and lymphangiogenesis, and its emerging importance as a therapeutic target.
Topics: Humans; Lymphangiogenesis; Thromboxanes; Lymphatic Vessels; Neoplasms; Inflammation
PubMed: 37150029
DOI: 10.1016/j.biopha.2023.114831 -
Cancer Science Nov 2023Ferroptosis, a newly discovered form of regulated cell death, has been reported to be associated with multiple cancers, including colorectal cancer (CRC). However, the...
Ferroptosis, a newly discovered form of regulated cell death, has been reported to be associated with multiple cancers, including colorectal cancer (CRC). However, the underlying molecular mechanism is still unclear. In this study, we identified B7H3 as a potential regulator of ferroptosis resistance in CRC. B7H3 knockdown decreased but B7H3 overexpression increased the ferroptosis resistance of CRC cells, as evidenced by the expression of ferroptosis-associated genes (PTGS2, FTL, FTH, and GPX4) and the levels of important indicators of ferroptosis (malondialdehyde, iron load). Moreover, B7H3 promoted ferroptosis resistance by regulating sterol regulatory element binding protein 2 (SREBP2)-mediated cholesterol metabolism. Both exogenous cholesterol supplementation and treatment with the SREBP2 inhibitor betulin reversed the effect of B7H3 on ferroptosis in CRC cells. Furthermore, we verified that B7H3 downregulated SREBP2 expression by activating the AKT pathway. Additionally, multiplex immunohistochemistry was carried out to show the expression of B7H3, prostaglandin-endoperoxide synthase 2, and SREBP2 in CRC tumor tissues, which was associated with the prognosis of patients with CRC. In summary, our findings reveal a role for B7H3 in regulating ferroptosis by controlling cholesterol metabolism in CRC.
Topics: Humans; Cholesterol; Colorectal Neoplasms; Cyclooxygenase 2; Ferroptosis; Iron
PubMed: 37661645
DOI: 10.1111/cas.15944 -
Molecular Therapy : the Journal of the... Dec 2023In vivo apoptosis of human mesenchymal stromal cells (MSCs) plays a critical role in delivering immunomodulation. Yet, caspase activity not only mediates the dying...
In vivo apoptosis of human mesenchymal stromal cells (MSCs) plays a critical role in delivering immunomodulation. Yet, caspase activity not only mediates the dying process but also death-independent functions that may shape the immunogenicity of apoptotic cells. Therefore, a better characterization of the immunological profile of apoptotic MSCs (ApoMSCs) could shed light on their mechanistic action and therapeutic applications. We analyzed the transcriptomes of MSCs undergoing apoptosis and identified several immunomodulatory factors and chemokines dependent on caspase activation following Fas stimulation. The ApoMSC secretome inhibited human T cell proliferation and activation, and chemoattracted monocytes in vitro. Both immunomodulatory activities were dependent on the cyclooxygenase2 (COX2)/prostaglandin E2 (PGE2) axis. To assess the clinical relevance of ApoMSC signature, we used the peripheral blood mononuclear cells (PBMCs) from a cohort of fistulizing Crohn's disease (CD) patients who had undergone MSC treatment (ADMIRE-CD). Compared with healthy donors, MSCs exposed to patients' PBMCs underwent apoptosis and released PGE2 in a caspase-dependent manner. Both PGE2 and apoptosis were significantly associated with clinical responses to MSCs. Our findings identify a new mechanism whereby caspase activation delivers ApoMSC immunosuppression. Remarkably, such molecular signatures could implicate translational tools for predicting patients' clinical responses to MSC therapy in CD.
Topics: Humans; Crohn Disease; Dinoprostone; Leukocytes, Mononuclear; Secretome; Mesenchymal Stem Cells; Immunomodulation; Apoptosis; Caspases
PubMed: 37805713
DOI: 10.1016/j.ymthe.2023.10.004 -
International Journal of Molecular... Nov 2023Tanshinone IIA (TSN) extracted from danshen () could protect cardiomyocytes against myocardial ischemia/reperfusion injury (IRI), however the underlying molecular...
Tanshinone IIA (TSN) extracted from danshen () could protect cardiomyocytes against myocardial ischemia/reperfusion injury (IRI), however the underlying molecular mechanisms of action remain unclear. The aim of the present study was to identify the protective effects of TSN and its mechanisms of action through studies. An anoxia/reoxygenation (A/R) injury model was established using H9c2 cells to simulate myocardial IRI . Before A/R, H9c2 cardiomyoblasts were pretreated with 8 µM TSN or 10 µM ferrostatin‑1 (Fer‑1) or erastin. The cell counting kit 8 (CCK‑8) and lactate dehydrogenase (LDH) assay kit were used to detect the cell viability and cytotoxicity. The levels of total iron, glutathione (GSH), glutathione disulfide (GSSG), malondialdehyde (MDA), ferrous iron, caspase‑3 activity, and reactive oxygen species (ROS) were assessed using commercial kit. The levels of mitochondrial membrane potential (MMP), lipid ROS, cell apoptosis, and mitochondrial permeability transition pore (mPTP) opening were detected by flow cytometry. Transmission electron microscopy (TEM) was used to observed the mitochondrial damage. Protein levels were detected by western blot analysis. The interaction between TSN and voltage‑dependent anion channel 1 (VDAC1) was evaluated by molecular docking simulation. The results showed that pretreatment with TSN and Fer‑1 significantly decreased cell viability, glutathione peroxidase 4 (GPX4) protein and GSH expression and GSH/GSSG ratio and inhibited upregulation of LDH activity, prostaglandin endoperoxide synthase 2 and VDAC1 protein expression, ROS levels, mitochondrial injury and GSSG induced by A/R. TSN also effectively inhibited the damaging effects of erastin treatment. Additionally, TSN increased MMP and Bcl‑2/Bax ratio, while decreasing levels of apoptotic cells, activating Caspase‑3 and closing the mPTP. These effects were blocked by VDAC1 overexpression and the results of molecular docking simulation studies revealed a direct interaction between TSN and VDAC1. In conclusion, TSN pretreatment effectively attenuated H9c2 cardiomyocyte damage in an A/R injury model and VDAC1‑mediated ferroptosis and apoptosis served a vital role in the protective effects of TSN.
Topics: Humans; Voltage-Dependent Anion Channel 1; Ferroptosis; Reactive Oxygen Species; Caspase 3; Myocardial Reperfusion Injury; Glutathione Disulfide; Molecular Docking Simulation; Myocytes, Cardiac; Apoptosis; Iron
PubMed: 37800609
DOI: 10.3892/ijmm.2023.5312