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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 -
International Journal of Molecular... Jun 2024The present study examined how P2X7 receptor knockout (KO) modulates central post-stroke pain (CPSP) induced by lesions of the ventrobasal complex (VBC) of the thalamus...
The present study examined how P2X7 receptor knockout (KO) modulates central post-stroke pain (CPSP) induced by lesions of the ventrobasal complex (VBC) of the thalamus in behaviors, molecular levels, and electrical recording tests. Following the experimental procedure, the wild-type and P2X7 receptor KO mice were injected with 10 mU/0.2 μL type IV collagenase in the VBC of the thalamus to induce an animal model of stroke-like thalamic hemorrhage. Behavioral data showed that the CPSP group induced thermal and mechanical pain. The P2X7 receptor KO group showed reduced thermal and mechanical pain responses compared to the CPSP group. Molecular assessments revealed that the CPSP group had lower expression of NeuN and KCC2 and higher expression of GFAP, IBA1, and BDNF. The P2X7 KO group showed lower expression of GFAP, IBA1, and BDNF but nonsignificant differences in KCC2 expression than the CPSP group. The expression of NKCC1, GABAa receptor, and TrkB did not differ significantly between the control, CPSP, and P2X7 receptor KO groups. Muscimol, a GABAa agonist, application increased multiunit numbers for monitoring many neurons and [Cl] outflux in the cytosol in the CPSP group, while P2X7 receptor KO reduced multiunit activity and increased [Cl] influx compared to the CPSP group. P2X4 receptor expression was significantly decreased in the 100 kDa but not the 50 kDa site in the P2X7 receptor KO group. Altogether, the P2X7 hypothesis of CPSP was proposed, wherein P2X7 receptor KO altered the CPSP pain responses, numbers of astrocytes and microglia, CSD amplitude of the anterior cingulate cortex and the medial dorsal thalamus, BDNF expression, [Cl] influx, and P2X4 expression in 100 kDa with P2X7 receptors. The present findings have implications for the clinical treatment of CPSP symptoms.
Topics: Animals; Receptors, Purinergic P2X7; Mice; Mice, Knockout; Stroke; K Cl- Cotransporters; Male; Pain; Disease Models, Animal; Brain-Derived Neurotrophic Factor; Symporters; Mice, Inbred C57BL; Neurons; Muscimol; Glial Fibrillary Acidic Protein; Thalamus
PubMed: 38928280
DOI: 10.3390/ijms25126577 -
International Journal of Molecular... Jun 2024Lysosomes are highly dynamic organelles that maintain cellular homeostasis and regulate fundamental cellular processes by integrating multiple metabolic pathways.... (Review)
Review
Lysosomes are highly dynamic organelles that maintain cellular homeostasis and regulate fundamental cellular processes by integrating multiple metabolic pathways. Lysosomal ion channels such as TRPML1-3, TPC1/2, ClC6/7, CLN7, and TMEM175 mediate the flux of Ca, Cl, Na, H, and K across lysosomal membranes in response to osmotic stimulus, nutrient-dependent signals, and cellular stresses. These ion channels serve as the crucial transducers of cell signals and are essential for the regulation of lysosomal biogenesis, motility, membrane contact site formation, and lysosomal homeostasis. In terms of pathophysiology, genetic variations in these channel genes have been associated with the development of lysosomal storage diseases, neurodegenerative diseases, inflammation, and cancer. This review aims to discuss the current understanding of the role of these ion channels in the central nervous system and to assess their potential as drug targets.
Topics: Humans; Lysosomes; Animals; Ion Channels; Central Nervous System; Lysosomal Storage Diseases; Neurodegenerative Diseases; Homeostasis
PubMed: 38928271
DOI: 10.3390/ijms25126565 -
International Journal of Molecular... Jun 2024Aquaporins (AQPs), particularly AQP4, play a crucial role in regulating fluid dynamics in the brain, impacting the development and resolution of edema following... (Review)
Review
Aquaporins (AQPs), particularly AQP4, play a crucial role in regulating fluid dynamics in the brain, impacting the development and resolution of edema following traumatic brain injury (TBI). This review examines the alterations in AQP expression and localization post-injury, exploring their effects on brain edema and overall injury outcomes. We discuss the underlying molecular mechanisms regulating AQP expression, highlighting potential therapeutic strategies to modulate AQP function. These insights provide a comprehensive understanding of AQPs in TBI and suggest novel approaches for improving clinical outcomes through targeted interventions.
Topics: Brain Injuries, Traumatic; Humans; Animals; Aquaporins; Brain Edema; Aquaporin 4; Hydrodynamics; Brain
PubMed: 38928258
DOI: 10.3390/ijms25126553 -
International Journal of Molecular... Jun 2024The peripheral nervous system can encounter alterations due to exposure to some of the most commonly used anticancer drugs (platinum drugs, taxanes, vinca alkaloids,... (Review)
Review
The peripheral nervous system can encounter alterations due to exposure to some of the most commonly used anticancer drugs (platinum drugs, taxanes, vinca alkaloids, proteasome inhibitors, thalidomide), the so-called chemotherapy-induced peripheral neurotoxicity (CIPN). CIPN can be long-lasting or even permanent, and it is detrimental for the quality of life of cancer survivors, being associated with persistent disturbances such as sensory loss and neuropathic pain at limb extremities due to a mostly sensory axonal polyneuropathy/neuronopathy. In the state of the art, there is no efficacious preventive/curative treatment for this condition. Among the reasons for this unmet clinical and scientific need, there is an uncomplete knowledge of the pathogenetic mechanisms. Ion channels and transporters are pivotal elements in both the central and peripheral nervous system, and there is a growing body of literature suggesting that they might play a role in CIPN development. In this review, we first describe the biophysical properties of these targets and then report existing data for the involvement of ion channels and transporters in CIPN, thus paving the way for new approaches/druggable targets to cure and/or prevent CIPN.
Topics: Humans; Antineoplastic Agents; Peripheral Nervous System Diseases; Ion Channels; Animals; Neurotoxicity Syndromes; Membrane Transport Proteins; Neoplasms
PubMed: 38928257
DOI: 10.3390/ijms25126552 -
International Journal of Molecular... Jun 2024Creatine transporter (CrT1) mediates cellular uptake of creatine (Cr), a nutrient pivotal in maintaining energy homeostasis in various tissues including intestinal...
Creatine transporter (CrT1) mediates cellular uptake of creatine (Cr), a nutrient pivotal in maintaining energy homeostasis in various tissues including intestinal epithelial cells (IECs). The impact of CrT1 deficiency on the pathogenesis of various psychiatric and neurological disorders has been extensively investigated. However, there are no studies on its regulation in IECs in health and disease. Current studies have determined differential expression of CrT1 along the length of the mammalian intestine and its dysregulation in inflammatory bowel disease (IBD)-associated inflammation and Adherent Invasive (AIEC) infection. CrT1 mRNA and protein levels in normal intestines and their alterations in inflammation and following AIEC infection were determined in vitro in model IECs (Caco-2/IEC-6) and in vivo in SAMP1/YitFc mice, a model of spontaneous ileitis resembling human IBD. CrT1 is differentially expressed in different regions of mammalian intestines with its highest expression in jejunum. In vitro, CrT1 function (Na-dependent C-Cr uptake), expression and promoter activity significantly decreased following TNFα/IL1β treatments and AIEC infection. SAMP1 mice and ileal organoids generated from SAMP1 mice also showed decreased CrT1 mRNA and protein compared to AKR controls. Our studies suggest that Cr deficiency in IECs secondary to CrT1 dysregulation could be a key factor contributing to IBD pathogenesis.
Topics: Animals; Escherichia coli Infections; Mice; Humans; Intestinal Mucosa; Caco-2 Cells; Plasma Membrane Neurotransmitter Transport Proteins; Inflammation; Escherichia coli; Inflammatory Bowel Diseases; Membrane Transport Proteins; Epithelial Cells; Creatine
PubMed: 38928243
DOI: 10.3390/ijms25126537 -
International Journal of Molecular... Jun 2024In different areas of the heart, action potential waveforms differ due to differences in the expressions of sodium, calcium, and potassium channels. One of the... (Review)
Review
In different areas of the heart, action potential waveforms differ due to differences in the expressions of sodium, calcium, and potassium channels. One of the characteristics of myocardial infarction (MI) is an imbalance in oxygen supply and demand, leading to ion imbalance. After MI, the regulation and expression levels of K, Ca, and Na ion channels in cardiomyocytes are altered, which affects the regularity of cardiac rhythm and leads to myocardial injury. Myocardial fibroblasts are the main effector cells in the process of MI repair. The ion channels of myocardial fibroblasts play an important role in the process of MI. At the same time, a large number of ion channels are expressed in immune cells, which play an important role by regulating the in- and outflow of ions to complete intracellular signal transduction. Ion channels are widely distributed in a variety of cells and are attractive targets for drug development. This article reviews the changes in different ion channels after MI and the therapeutic drugs for these channels. We analyze the complex molecular mechanisms behind myocardial ion channel regulation and the challenges in ion channel drug therapy.
Topics: Myocardial Infarction; Humans; Ion Channels; Animals; Myocytes, Cardiac; Myocardium; Signal Transduction; Fibroblasts
PubMed: 38928173
DOI: 10.3390/ijms25126467 -
International Journal of Molecular... Jun 2024Obesity is a risk factor for type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). Adipose tissue (AT) extracellular vesicles (EVs) could play a role in...
Extracellular Vesicles Secreted by Adipose Tissue during Obesity and Type 2 Diabetes Mellitus Influence Reverse Cholesterol Transport-Related Gene Expression in Human Macrophages.
Obesity is a risk factor for type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). Adipose tissue (AT) extracellular vesicles (EVs) could play a role in obesity and T2DM associated CVD progression via the influence of their specific cargo on gene expression in recipient cells. The aim of this work was to evaluate the effects of AT EVs of patients with obesity with/without T2DM on reverse cholesterol transport (RCT)-related gene expression in human monocyte-derived macrophages (MDMs) from healthy donors. AT EVs were obtained after ex vivo cultivation of visceral and subcutaneous AT (VAT and SAT, respectively). , , , , and mRNA levels in MDMs as well as in origine AT were determined by a real-time PCR. T2DM VAT and SAT EVs induced gene expression whereas and mRNA levels were simultaneously downregulated. mRNA levels also decreased in the presence of VAT EVs of obese patients without T2DM. In contrast and mRNA levels tended to increase with the addition of obese AT EVs. Thus, AT EVs can influence RCT gene expression in MDMs during obesity, and the effects are dependent on T2DM status.
Topics: Humans; Diabetes Mellitus, Type 2; Extracellular Vesicles; Obesity; Liver X Receptors; Macrophages; Cholesterol; ATP Binding Cassette Transporter, Subfamily G, Member 1; Adipose Tissue; PPAR gamma; Female; ATP Binding Cassette Transporter 1; Male; Middle Aged; Biological Transport; Gene Expression Regulation; Adult; RNA, Messenger
PubMed: 38928163
DOI: 10.3390/ijms25126457 -
International Journal of Molecular... Jun 2024Chloroquine (CQ) is a 4-aminoquinoline derivative largely employed in the management of malaria. CQ treatment exploits the drug's ability to cross the erythrocyte...
Chloroquine (CQ) is a 4-aminoquinoline derivative largely employed in the management of malaria. CQ treatment exploits the drug's ability to cross the erythrocyte membrane, inhibiting heme polymerase in malarial trophozoites. Accumulation of CQ prevents the conversion of heme to hemozoin, causing its toxic buildup, thus blocking the survival of Plasmodium parasites. Recently, it has been reported that CQ is able to exert antiviral properties, mainly against HIV and SARS-CoV-2. This renewed interest in CQ treatment has led to the development of new studies which aim to explore its side effects and long-term outcome. Our study focuses on the effects of CQ in non-parasitized red blood cells (RBCs), investigating hemoglobin (Hb) functionality, the anion exchanger 1 (AE1) or band 3 protein, caspase 3 and protein tyrosine phosphatase 1B (PTP-1B) activity, intra and extracellular ATP levels, and the oxidative state of RBCs. Interestingly, CQ influences the functionality of both Hb and AE1, the main RBC proteins, affecting the properties of Hb oxygen affinity by shifting the conformational structure of the molecule towards the R state. The influence of CQ on AE1 flux leads to a rate variation of anion exchange, which begins at a concentration of 2.5 μM and reaches its maximum effect at 20 µM. Moreover, a significant decrease in intra and extracellular ATP levels was observed in RBCs pre-treated with 10 µM CQ vs. erythrocytes under normal conditions. This effect is related to the PTP-1B activity which is reduced in RBCs incubated with CQ. Despite these metabolic alterations to RBCs caused by exposure to CQ, no signs of variations in oxidative state or caspase 3 activation were recorded. Our results highlight the antithetical effects of CQ on the functionality and metabolism of RBCs, and encourage the development of new research to better understand the multiple potentiality of the drug.
Topics: Erythrocytes; Humans; Chloroquine; Hemoglobins; Anion Exchange Protein 1, Erythrocyte; Adenosine Triphosphate; Antimalarials; Caspase 3
PubMed: 38928131
DOI: 10.3390/ijms25126424 -
International Journal of Molecular... Jun 2024The gene encodes for the CFTR ion channel, which is responsible for the transport of chloride and bicarbonate across the plasma membrane. Mutations in the gene result...
The gene encodes for the CFTR ion channel, which is responsible for the transport of chloride and bicarbonate across the plasma membrane. Mutations in the gene result in impaired ion transport, subsequently leading to perturbed secretion in all exocrine glands and, therefore, the multi-organ disease cystic fibrosis (CF). In recent years, several studies have reported on CFTR expression in immune cells as demonstrated by immunofluorescence, flow cytometry, and immunoblotting. However, these data are mainly restricted to single-cell populations and show significant variation depending on the methodology used. Here, we investigated transcription and protein expression using standardized protocols in a comprehensive panel of immune cells. Methods: We applied a high-resolution Western blot protocol using a combination of highly specific monoclonal CFTR antibodies that have been optimized for the detection of CFTR in epithelial cells and healthy primary immune cell subpopulations sorted by flow cytometry and used immortalized cell lines as controls. The specificity of CFTR protein detection was controlled by peptide competition and enzymatic Peptide-N-Glycosidase-F (PNGase) digest. transcripts were analyzed using quantitative real-time PCR and normalized to the level of epithelial T84 cells as a reference. Results: mRNA expression could be shown for primary CD4 T cells, NK cells, as well as differentiated THP-1 and Jurkat T cells. In contrast, we failed to detect transcripts for CD14 monocytes and undifferentiated THP-1 cells, as well as for B cells and CD8 T cells. Prominent immunoreactive bands were detectable by immunoblotting with the combination of four CFTR antibodies targeting different epitopes of the CFTR protein. However, in biosamples of non-epithelial origin, these CFTR-like protein bands could be unmasked as false positives through peptide competition or PNGase digest, meaning that the observed mRNA transcripts were not necessarily translated into CFTR proteins, which could be detected via immunoblotting. Our results confirm that mRNA expression in immune cells is many times lower than in that cells of epithelial origin. The immunoreactive signals in immune cells turned out to be false positives, and may be provoked by the presence of a high-affinity protein with a similar epitope. Non-specific binding (e.g., Fab-interaction with glycosyl branches) might also contribute to false positive signals. Our findings highlight the necessity of accurate controls, such as CFTR-negative cells, as well as peptide competition and glycolytic digest in order to identify genuine CFTR protein by immunoblotting. Our data suggest, furthermore, that CFTR protein expression data from techniques such as histology, for which the absence of a molecular weight or other independent control prevents the unmasking of false positive immunoreactive signals, must be interpreted carefully as well.
Topics: Cystic Fibrosis Transmembrane Conductance Regulator; Humans; RNA, Messenger; Leukocytes, Mononuclear; Blotting, Western; Real-Time Polymerase Chain Reaction; Cystic Fibrosis; Killer Cells, Natural; Flow Cytometry; CD4-Positive T-Lymphocytes
PubMed: 38928073
DOI: 10.3390/ijms25126367