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PloS One 2024The intricate process of neuronal differentiation integrates multiple signals to induce transcriptional, morphological, and electrophysiological changes that reshape the...
The intricate process of neuronal differentiation integrates multiple signals to induce transcriptional, morphological, and electrophysiological changes that reshape the properties of neural precursor cells during their maturation and migration process. An increasing number of neurotransmitters and biomolecules have been identified as molecular signals that trigger and guide this process. In this sense, taurine, a sulfur-containing, non-essential amino acid widely expressed in the mammal brain, modulates the neuronal differentiation process. In this study, we describe the effect of taurine acting via the ionotropic GABAA receptor and the metabotropic GABAB receptor on the neuronal differentiation and electrophysiological properties of precursor cells derived from the subventricular zone of the mouse brain. Taurine stimulates the number of neurites and favors the dendritic complexity of the neural precursor cells, accompanied by changes in the somatic input resistance and the strength of inward and outward membranal currents. At the pharmacological level, the blockade of GABAA receptors inhibits these effects, whereas the stimulation of GABAB receptors has no positive effects on the taurine-mediated differentiation process. Strikingly, the blockade of the GABAB receptor with CGP533737 stimulates neurite outgrowth, dendritic complexity, and membranal current kinetics of neural precursor cells. The effects of taurine on the differentiation process involve Ca2+ mobilization and the activation of intracellular signaling cascades since chelation of intracellular calcium with BAPTA-AM, and inhibition of the CaMKII, ERK1/2, and Src kinase inhibits the neurite outgrowth of neural precursor cells of the subventricular zone.
Topics: Animals; Neural Stem Cells; Receptors, GABA-B; Mice; Cell Differentiation; Receptors, GABA-A; Lateral Ventricles; Taurine; Neurogenesis; Calcium
PubMed: 38913632
DOI: 10.1371/journal.pone.0305853 -
ELife Jun 2024The serotonin-gated ion channel (5-HTR) mediates excitatory neuronal communication in the gut and the brain. It is the target for setrons, a class of competitive...
The serotonin-gated ion channel (5-HTR) mediates excitatory neuronal communication in the gut and the brain. It is the target for setrons, a class of competitive antagonists widely used as antiemetics, and is involved in several neurological diseases. Cryo-electron microscopy (cryo-EM) of the 5-HTR in complex with serotonin or setrons revealed that the protein has access to a wide conformational landscape. However, assigning known high-resolution structures to actual states contributing to the physiological response remains a challenge. In the present study, we used voltage-clamp fluorometry (VCF) to measure simultaneously, for 5-HTR expressed at a cell membrane, conformational changes by fluorescence and channel opening by electrophysiology. Four positions identified by mutational screening report motions around and outside the serotonin-binding site through incorporation of cysteine-tethered rhodamine dyes with or without a nearby quenching tryptophan. VCF recordings show that the 5-HTR has access to four families of conformations endowed with distinct fluorescence signatures: 'resting-like' without ligand, 'inhibited-like' with setrons, 'pre-active-like' with partial agonists, and 'active-like' (open channel) with partial and strong agonists. Data are remarkably consistent with cryo-EM structures, the fluorescence partners matching respectively apo, setron-bound, 5-HT bound-closed, and 5-HT-bound-open conformations. Data show that strong agonists promote a concerted motion of all fluorescently labeled sensors during activation, while partial agonists, especially when loss-of-function mutations are engineered, stabilize both active and pre-active conformations. In conclusion, VCF, though the monitoring of electrophysiologically silent conformational changes, illuminates allosteric mechanisms contributing to signal transduction and their differential regulation by important classes of physiological and clinical effectors.
Topics: Receptors, Serotonin, 5-HT3; Fluorometry; Humans; Patch-Clamp Techniques; Protein Conformation; Serotonin; Cryoelectron Microscopy; HEK293 Cells; Binding Sites; Ion Channel Gating
PubMed: 38913422
DOI: 10.7554/eLife.93174 -
ELife Jun 2024Metabolic disorders are highly prevalent in modern society. Exercise mimetics are defined as pharmacological compounds that can produce the beneficial effects of...
Metabolic disorders are highly prevalent in modern society. Exercise mimetics are defined as pharmacological compounds that can produce the beneficial effects of fitness. Recently, there has been increased interest in the role of eugenol and transient receptor potential vanilloid 1 (TRPV1) in improving metabolic health. The aim of this study was to investigate whether eugenol acts as an exercise mimetic by activating TRPV1. Here, we showed that eugenol improved endurance capacity, caused the conversion of fast-to-slow muscle fibers, and promoted white fat browning and lipolysis in mice. Mechanistically, eugenol promoted muscle fiber-type transformation by activating TRPV1-mediated CaN signaling pathway. Subsequently, we identified IL-15 as a myokine that is regulated by the CaN/nuclear factor of activated T cells cytoplasmic 1 (NFATc1) signaling pathway. Moreover, we found that TRPV1-mediated CaN/NFATc1 signaling, activated by eugenol, controlled IL-15 levels in C2C12 myotubes. Our results suggest that eugenol may act as an exercise mimetic to improve metabolic health via activating the TRPV1-mediated CaN signaling pathway.
Topics: TRPV Cation Channels; Animals; Interleukin-15; Eugenol; Mice; Muscle Fibers, Skeletal; NFATC Transcription Factors; Physical Conditioning, Animal; Signal Transduction; Male; Mice, Inbred C57BL; Myokines
PubMed: 38913071
DOI: 10.7554/eLife.90724 -
JCI Insight May 2024Patients with autosomal dominant polycystic kidney disease (ADPKD), a genetic disease due to mutations of the PKD1 or PKD2 gene, show signs of complement activation in...
Patients with autosomal dominant polycystic kidney disease (ADPKD), a genetic disease due to mutations of the PKD1 or PKD2 gene, show signs of complement activation in the urine and cystic fluid, but their pathogenic role in cystogenesis is unclear. We tested the causal relationship between complement activation and cyst growth using a Pkd1KO renal tubular cell line and newly generated conditional Pkd1-/- C3-/- mice. Pkd1-deficient tubular cells have increased expression of complement-related genes (C3, C5, CfB, C3ar, and C5ar1), while the gene and protein expression of complement regulators DAF, CD59, and Crry is decreased. Pkd1-/- C3-/- mice are unable to fully activate the complement cascade and are characterized by a significantly slower kidney cystogenesis, preserved renal function, and reduced intrarenal inflammation compared with Pkd1-/- C3+/+ controls. Transgenic expression of the cytoplasmic C-terminal tail of Pkd1 in Pkd1KO cells lowered C5ar1 expression, restored Daf levels, and reduced cell proliferation. Consistently, both DAF overexpression and pharmacological inhibition of C5aR1 (but not C3aR) reduced Pkd1KO cell proliferation. In conclusion, the loss of Pkd1 promotes unleashed activation of locally produced complement by downregulating DAF expression in renal tubular cells. Increased C5a formation and C5aR1 activation in tubular cells promotes cyst growth, offering a new therapeutic target.
Topics: Animals; Polycystic Kidney, Autosomal Dominant; Mice; CD55 Antigens; Complement C3; Mice, Knockout; Receptor, Anaphylatoxin C5a; Disease Models, Animal; Complement Activation; TRPP Cation Channels; Humans; Cell Proliferation; Male; Cell Line; Receptors, Complement 3b
PubMed: 38912583
DOI: 10.1172/jci.insight.175220 -
JCI Insight May 2024Peripheral nerve injury-induced neuronal hyperactivity in the dorsal root ganglion (DRG) participates in neuropathic pain. The calcium-activated potassium channel...
Peripheral nerve injury-induced neuronal hyperactivity in the dorsal root ganglion (DRG) participates in neuropathic pain. The calcium-activated potassium channel subfamily N member 1 (KCNN1) mediates action potential afterhyperpolarization (AHP) and gates neuronal excitability. However, the specific contribution of DRG KCNN1 to neuropathic pain is not yet clear. We report that chronic constriction injury (CCI) of the unilateral sciatic nerve or unilateral ligation of the fourth lumbar nerve produced the downregulation of Kcnn1 mRNA and KCNN1 protein in the injured DRG. This downregulation was partially attributed to a decrease in DRG estrogen-related receptor gamma (ESRRG), a transcription factor, which led to reduced binding to the Kcnn1 promoter. Rescuing this downregulation prevented CCI-induced decreases in total potassium voltage currents and AHP currents, reduced excitability in the injured DRG neurons, and alleviated CCI-induced development and maintenance of nociceptive hypersensitivities, without affecting locomotor function and acute pain. Mimicking the CCI-induced DRG KCNN1 downregulation resulted in augmented responses to mechanical, heat, and cold stimuli in naive mice. Our findings indicate that ESRRG-controlled downregulation of DRG KCNN1 is likely essential for the development and maintenance of neuropathic pain. Thus, KCNN1 may serve as a potential target for managing this disorder.
Topics: Animals; Neuralgia; Ganglia, Spinal; Mice; Down-Regulation; Sensory Receptor Cells; Male; Peripheral Nerve Injuries; Mice, Inbred C57BL; Sciatic Nerve; Disease Models, Animal; Intermediate-Conductance Calcium-Activated Potassium Channels; Action Potentials
PubMed: 38912580
DOI: 10.1172/jci.insight.180085 -
Frontiers in Microbiology 2024Biodegradation was considered a promising and environmentally friendly method for treating environmental pollution caused by diuron. However, the mechanisms of...
Biodegradation was considered a promising and environmentally friendly method for treating environmental pollution caused by diuron. However, the mechanisms of biodegradation of diuron required further research. In this study, the degradation process of diuron by SL-6 was systematically investigated. The results suggested that the antioxidant system of strain SL-6 was activated by adding diuron, thereby alleviating their oxidative stress response. In addition, degradation product analysis showed that diuron in strain SL-6 was mainly degraded by urea bridge cleavage, dehalogenation, deamination, and ring opening, and finally -muconic acid was generated. The combined analysis of metabolomics and transcriptomics revealed the biodegradation and adaptation mechanism of strain SL-6 to diuron. Metabolomics analysis showed that after the strain SL-6 was exposed to diuron, metabolic pathways such as tricarboxylic acid cycle (-muconic acid), glutathione metabolism (oxidized glutathione), and urea cycle (arginine) were reprogrammed in the cells. Furthermore, diuron could induce the production of membrane transport proteins in strain SL-6 cells and overexpress antioxidant enzyme genes, finally ultimately promoting the up-regulation of genes encoding amide hydrolases and dioxygenases, which was revealed by transcriptomics studies. This work enriched the biodegradation mechanism of phenylurea herbicides and provided guidance for the removal of diuron residues in the environment and promoting agriculture sustainable development.
PubMed: 38912345
DOI: 10.3389/fmicb.2024.1403279 -
Bone Research Jun 2024Stem/progenitor cells differentiate into different cell lineages during organ development and morphogenesis. Signaling pathway networks and mechanotransduction are...
Stem/progenitor cells differentiate into different cell lineages during organ development and morphogenesis. Signaling pathway networks and mechanotransduction are important factors to guide the lineage commitment of stem/progenitor cells during craniofacial tissue morphogenesis. Here, we used tooth root development as a model to explore the roles of FGF signaling and mechanotransduction as well as their interaction in regulating the progenitor cell fate decision. We show that Fgfr1 is expressed in the mesenchymal progenitor cells and their progeny during tooth root development. Loss of Fgfr1 in Gli1 progenitors leads to hyperproliferation and differentiation, which causes narrowed periodontal ligament (PDL) space with abnormal cementum/bone formation leading to ankylosis. We further show that aberrant activation of WNT signaling and mechanosensitive channel Piezo2 occurs after loss of FGF signaling in Gli1-Cre;Fgfr1 mice. Overexpression of Piezo2 leads to increased osteoblastic differentiation and decreased Piezo2 leads to downregulation of WNT signaling. Mechanistically, an FGF/PIEZO2/WNT signaling cascade plays a crucial role in modulating the fate of progenitors during root morphogenesis. Downregulation of WNT signaling rescues tooth ankylosis in Fgfr1 mutant mice. Collectively, our findings uncover the mechanism by which FGF signaling regulates the fate decisions of stem/progenitor cells, and the interactions among signaling pathways and mechanotransduction during tooth root development, providing insights for future tooth root regeneration.
Topics: Animals; Wnt Signaling Pathway; Tooth Root; Mechanotransduction, Cellular; Fibroblast Growth Factors; Mice; Cell Differentiation; Stem Cells; Receptor, Fibroblast Growth Factor, Type 1; Ion Channels
PubMed: 38910207
DOI: 10.1038/s41413-024-00345-5 -
Lipids in Health and Disease Jun 2024Overweight, often known as obesity, is the abnormal and excessive accumulation of fat that exposes the health of a person at risk by increasing the likelihood that they...
BACKGROUND
Overweight, often known as obesity, is the abnormal and excessive accumulation of fat that exposes the health of a person at risk by increasing the likelihood that they may experience many chronic conditions. Consequently, obesity has become a global health threat, presenting serious health issues, and attracting a lot of attention in the healthcare profession and the scientific community.
METHOD
This study aims to explore the anti-adipogenic properties of 7-MEGA™ in an attempt to address obesity, using both in vitro and in vivo research. The effects of 7MEGA™ at three distinct concentrations were investigated in obese mice who were given a high-fat diet (HFD) and 3T3-L1 adipocytes.
RESULTS
7MEGA™ decreased the total fat mass, overall body weight, and the perirenal and subcutaneous white adipose tissue (PWAT and SWAT) contents in HFD mice. Additionally, 7MEGA™ showed promise in improving the metabolic health of individuals with obesity and regulate the levels of insulin hormone, pro-inflammatory cytokines and adipokines. Furthermore, Peroxisome proliferator-activated receptors (PPAR) α and γ, Uncoupling Protein 1 (UCP-1), Sterol Regulatory Element-Binding Protein 1 (SREBP-1), Fatty Acid-Binding Protein 4 (FABP4), Fatty Acid Synthase (FAS), Acetyl-CoA Carboxylase (ACC), Stearoyl-CoA Desaturase-1 (SCD-1) and CCAAT/Enhancer-Binding Protein (C/EBPα) were among the adipogenic regulators that 7MEGA™ could regulate.
CONCLUSION
In summary, this study uncovered that 7MEGA™ demonstrates anti-adipogenic and anti-obesity effects, suggesting its potential in combating obesity.
Topics: Animals; Diet, High-Fat; Adipogenesis; Obesity; Mice; 3T3-L1 Cells; Adipocytes; Mice, Inbred C57BL; Male; PPAR gamma; Sterol Regulatory Element Binding Protein 1; Stearoyl-CoA Desaturase; Mice, Obese; Fatty Acid-Binding Proteins; Adipokines; Anti-Obesity Agents; Uncoupling Protein 1; Adipose Tissue, White; CCAAT-Enhancer-Binding Proteins
PubMed: 38909257
DOI: 10.1186/s12944-024-02175-0 -
Systematic Parasitology Jun 2024Eight species of Pandarus Leach, 1816 collected from hosts caught off South Africa are reported. These species include P. bicolor Leach, 1816, P. niger Kirtisinghe, 1950...
Eight species of Pandarus Leach, 1816 collected from hosts caught off South Africa are reported. These species include P. bicolor Leach, 1816, P. niger Kirtisinghe, 1950 and P. carcharhini Ho, 1963 belonging to the "bicolor" group and P. cranchii Leach, 1819, P. satyrus Dana, 1849, P. smithii Rathbun, 1886 and P. sinuatus Say, 1818 belonging to the "cranchii" group. Notes on previous and new distinguishing features are provided with illustrations, specifically the relative lengths of the dorsal plates and caudal rami as well as the structure of the distomedial spine on the second segment of leg 1 exopod. Additionally, illustrated re-descriptions are provided for P. satyrus and P. sinuatus. Furthermore, a new species Pandarus echinifer n. sp., also belonging to the "cranchii" group, collected from the snaggletooth shark Hemipristis elongata (Klunzinger) is described. This species is most similar to P. sinuatus but can be distinguished from it by the heavily spinulated distomedial spine on the last segment of the first leg exopod. Molecular analysis of the cytochrome oxidase I partial gene is used to calculate sequence divergences amongst different individuals and species. According to the results (as well as based on morphological characters) P. rhincodonicus Norman, Newbound & Knott, 2000 is a synonym of P. cranchii. New hosts and geographic localities from South Africa (and Ningaloo Park, Western Australia) are reported.
Topics: Animals; South Africa; Species Specificity; Elasmobranchii; Copepoda; Phylogeny; Electron Transport Complex IV; Male; Female
PubMed: 38907944
DOI: 10.1007/s11230-024-10167-y -
Cellular and Molecular Neurobiology Jun 2024The circadian system is a conserved time-keeping machinery that regulates a wide range of processes such as sleep/wake, feeding/fasting, and activity/rest cycles to...
The circadian system is a conserved time-keeping machinery that regulates a wide range of processes such as sleep/wake, feeding/fasting, and activity/rest cycles to coordinate behavior and physiology. Circadian disruption can be a contributing factor in the development of metabolic diseases, inflammatory disorders, and higher risk of cancer. Glioblastoma (GBM) is a highly aggressive grade 4 brain tumor that is resistant to conventional therapies and has a poor prognosis after diagnosis, with a median survival of only 12-15 months. GBM cells kept in culture were shown to contain a functional circadian oscillator. In seeking more efficient therapies with lower side effects, we evaluated the pharmacological modulation of the circadian clock by targeting the cytosolic kinases glycogen synthase kinase-3 (GSK-3) and casein kinase 1 ε/δ (CK1ε/δ) with specific inhibitors (CHIR99021 and PF670462, respectively), the cryptochrome protein stabilizer (KL001), or circadian disruption after Per2 knockdown expression in GBM-derived cells. CHIR99021-treated cells had a significant effect on cell viability, clock protein expression, migration, and cell cycle distribution. Moreover, cultures exhibited higher levels of reactive oxygen species and alterations in lipid droplet content after GSK-3 inhibition compared to control cells. The combined treatment of CHIR99021 with temozolomide was found to improve the effect on cell viability compared to temozolomide therapy alone. Per2 disruption affected both GBM migration and cell cycle progression. Overall, our results suggest that pharmacological modulation or molecular clock disruption severely affects GBM cell biology.
Topics: Glioblastoma; Humans; Cell Line, Tumor; Brain Neoplasms; Pyridines; Cell Survival; Cytosol; Glycogen Synthase Kinase 3; Pyrimidines; Cell Movement; Circadian Clocks; CLOCK Proteins; Period Circadian Proteins; Reactive Oxygen Species
PubMed: 38907776
DOI: 10.1007/s10571-024-01485-2