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Stem Cell Research & Therapy Nov 2023The metabolic reprogramming of mesenchymal stem/stromal cells (MSC) favoring glycolysis has recently emerged as a new approach to improve their immunotherapeutic...
BACKGROUND
The metabolic reprogramming of mesenchymal stem/stromal cells (MSC) favoring glycolysis has recently emerged as a new approach to improve their immunotherapeutic abilities. This strategy is associated with greater lactate release, and interestingly, recent studies have proposed lactate as a functional suppressive molecule, changing the old paradigm of lactate as a waste product. Therefore, we evaluated the role of lactate as an alternative mediator of MSC immunosuppressive properties and its contribution to the enhanced immunoregulatory activity of glycolytic MSCs.
MATERIALS AND METHODS
Murine CD4 T cells from C57BL/6 male mice were differentiated into proinflammatory Th1 or Th17 cells and cultured with either L-lactate, MSCs pretreated or not with the glycolytic inductor, oligomycin, and MSCs pretreated or not with a chemical inhibitor of lactate dehydrogenase A (LDHA), galloflavin or LDH siRNA to prevent lactate production. Additionally, we validated our results using human umbilical cord-derived MSCs (UC-MSCs) in a murine model of delayed type 1 hypersensitivity (DTH).
RESULTS
Our results showed that 50 mM of exogenous L-lactate inhibited the proliferation rate and phenotype of CD4 T cell-derived Th1 or Th17 by 40% and 60%, respectively. Moreover, the suppressive activity of both glycolytic and basal MSCs was impaired when LDH activity was reduced. Likewise, in the DTH inflammation model, lactate production was required for MSC anti-inflammatory activity. This lactate dependent-immunosuppressive mechanism was confirmed in UC-MSCs through the inhibition of LDH, which significantly decreased their capacity to control proliferation of activated CD4 and CD8 human T cells by 30%.
CONCLUSION
These findings identify a new MSC immunosuppressive pathway that is independent of the classical suppressive mechanism and demonstrated that the enhanced suppressive and therapeutic abilities of glycolytic MSCs depend at least in part on lactate production.
Topics: Humans; Male; Animals; Mice; Mice, Inbred C57BL; Lactic Acid; Immunosuppressive Agents; Mesenchymal Stem Cells; Cell Differentiation
PubMed: 37981698
DOI: 10.1186/s13287-023-03549-4 -
Life Science Alliance Feb 2024Cristae membranes have been recently shown to undergo intramitochondrial merging and splitting events. Yet, the metabolic and bioenergetic factors regulating them are...
Cristae membranes have been recently shown to undergo intramitochondrial merging and splitting events. Yet, the metabolic and bioenergetic factors regulating them are unclear. Here, we investigated whether and how cristae morphology and dynamics are dependent on oxidative phosphorylation (OXPHOS) complexes, the mitochondrial membrane potential (ΔΨ), and the ADP/ATP nucleotide translocator. Advanced live-cell STED nanoscopy combined with in-depth quantification were employed to analyse cristae morphology and dynamics after treatment of mammalian cells with rotenone, antimycin A, oligomycin A, and CCCP. This led to formation of enlarged mitochondria along with reduced cristae density but did not impair cristae dynamics. CCCP treatment leading to ΔΨ abrogation even enhanced cristae dynamics showing its ΔΨ-independent nature. Inhibition of OXPHOS complexes was accompanied by reduced ATP levels but did not affect cristae dynamics. However, inhibition of ADP/ATP exchange led to aberrant cristae morphology and impaired cristae dynamics in a mitochondrial subset. In sum, we provide quantitative data of cristae membrane remodelling under different conditions supporting an important interplay between OXPHOS, metabolite exchange, and cristae membrane dynamics.
Topics: Animals; Carbonyl Cyanide m-Chlorophenyl Hydrazone; Mitochondria; Mitochondrial Membranes; Oxidative Phosphorylation; Adenosine Triphosphate; Mammals
PubMed: 37957016
DOI: 10.26508/lsa.202302386 -
ACS Infectious Diseases Dec 2023Primary amebic meningoencephalitis (PAM), a brain infection caused by a free-living ameba , leads to an extensive inflammation of the brain and death within 1-18 (median...
Primary amebic meningoencephalitis (PAM), a brain infection caused by a free-living ameba , leads to an extensive inflammation of the brain and death within 1-18 (median 5) days after symptoms begin. Although natural products have played a significant role in the development of drugs for over a century, research focusing on identifying new natural product-based anti- agents is limited. We undertook a large-scale ATP bioluminescence-based screen of about 10,000 unique marine microbial metabolite mixtures against the trophozoites of . Our screen identified about 100 test materials with >90% inhibition at 50 μg/mL and a dose-response study found 20 of these active test materials exhibiting an EC ranging from 0.2 to 2 μg/mL. Examination of four of these potent metabolite mixtures, derived from our actinomycete strains CNT671, CNT756, and CNH301, resulted in the isolation of a pure metabolite identified as oligomycin D. Oligomycin D exhibited nanomolar potency on multiple genotypes of , and it was five- or 850-times more potent than the recommended drugs amphotericin B or miltefosine. Oligomycin D is fast-acting and reached its EC in 10 h, and it was also able to inhibit the invasiveness of significantly when tested on a matrigel invasion assay. Since oligomycin is known to manifest inhibitory activity against FF ATP synthase, we tested different FF ATP synthase inhibitors and identified a natural peptide leucinostatin as a fast-acting amebicidal compound with nanomolar potency on multiple strains.
Topics: Humans; Central Nervous System Protozoal Infections; Rutamycin; Naegleria fowleri; Amphotericin B; Amebicides
PubMed: 37943251
DOI: 10.1021/acsinfecdis.3c00437 -
The FEBS Journal Mar 2024Gastric neoplasm is a high-mortality cancer worldwide. Chemoresistance is the obstacle against gastric cancer treatment. Mitochondrial dysfunction has been observed to...
Gastric neoplasm is a high-mortality cancer worldwide. Chemoresistance is the obstacle against gastric cancer treatment. Mitochondrial dysfunction has been observed to promote malignant progression. However, the underlying mechanism is still unclear. The mitokine growth differentiation factor 15 (GDF15) is a significant biomarker for mitochondrial disorder and is activated by the integrated stress response (ISR) pathway. The serum level of GDF15 was found to be correlated with the poor prognosis of gastric cancer patients. In this study, we found that high GDF15 protein expression might increase disease recurrence in adjuvant chemotherapy-treated gastric cancer patients. Moreover, treatment with mitochondrial inhibitors, especially oligomycin (a complex V inhibitor) and salubrinal (an ISR activator), respectively, was found to upregulate GDF15 and enhance cisplatin insensitivity of human gastric cancer cells. Mechanistically, it was found that the activating transcription factor 4-C/EBP homologous protein pathway has a crucial function in the heightened manifestation of GDF15. In addition, reactive oxygen species-activated general control nonderepressible 2 mediates the oligomycin-induced ISR, and upregulates GDF15. The GDF15-glial cell-derived neurotrophic factor family receptor a-like-ISR-cystine/glutamate transporter-enhanced glutathione production was found to be involved in cisplatin resistance. These results suggest that mitochondrial dysfunction might enhance cisplatin insensitivity through GDF15 upregulation, and targeting mitokine GDF15-ISR regulation might be a strategy against cisplatin resistance of gastric cancer.
Topics: Humans; Cisplatin; Stomach Neoplasms; Up-Regulation; Growth Differentiation Factor 15; Oligomycins
PubMed: 37935441
DOI: 10.1111/febs.16992 -
Comparative Biochemistry and... 2024Broadcast-spawning marine mussels rely on high sperm motility for successful fertilization in the dynamic seawater environment. Mitochondria are typically considered the...
Broadcast-spawning marine mussels rely on high sperm motility for successful fertilization in the dynamic seawater environment. Mitochondria are typically considered the primary source of ATP generation via oxidative phosphorylation (OXPHOS); however, the ATP generation pathways of mussel sperm have not been fully characterized. To better understand the importance of both OXPHOS and glycolysis for mussel sperm function, we conducted experiments inhibiting these pathways in sperm from Mytilus edulis. Our results indicate that oligomycin, an inhibitor of the mitochondrial ATP synthase, immediately decreased sperm motility rate, velocity, and ATP content, while 2-deoxy-d-glucose, a glycolysis inhibitor, had no effect. The OXPHOS inhibitor rotenone also partially reduced sperm motility rate and velocity. Interestingly, no evidence was found for the inhibitors' effects on the content of energy-rich compounds (lipids, carbohydrates, and proteins) in the mussels' sperm, indicating only modest energy demand to fuel sperm motility. Based on these findings, we conclude that OXPHOS is the primary energy source for sperm motility in marine mussels. Our study sheds light on the intricacies of mussel sperm physiology and highlights the importance of understanding the energy requirements for successful fertilization in broadcast-spawning marine invertebrates.
Topics: Male; Animals; Oxidative Phosphorylation; Sperm Motility; Mytilus edulis; Semen; Glycolysis; Spermatozoa; Adenosine Triphosphate; Mytilus
PubMed: 37898360
DOI: 10.1016/j.cbpb.2023.110909 -
Molecular Medicine Reports Dec 2023Adipose tissue serves a significant role in the regulation of energy metabolism in the body. The re‑esterification of the fatty acids generated during lipolysis is...
Adipose tissue serves a significant role in the regulation of energy metabolism in the body. The re‑esterification of the fatty acids generated during lipolysis is critical for efficient lipolysis. However, the effect of the intracellular energy state on lipolytic activity and fatty acid re‑esterification during lipolysis is not yet fully understood. The present study aimed to assess the effect of the intracellular energy state on lipolytic activity and fatty acid re‑esterification during lipolysis. 3T3‑L1 adipocytes were incubated with mitochondrial respiratory chain inhibitors, oligomycin A or rotenone, during isoproterenol stimulation; and glycerol, glucose and lactate concentrations in the medium were measured. Western blot analysis was performed to examine the phosphorylation levels of cAMP‑dependent protein kinase A (PKA). The results showed that inhibition of mitochondrial ATP synthesis decreased catecholamine‑stimulated lipolysis without affecting PKA signaling. The inhibition of mitochondrial respiration increased glucose uptake and lactate production, indicating that a large amount of glucose taken up into the cell was preferentially used for ATP production rather than for re‑esterification. In conclusion, the results of the present study suggested that the energy state during lipolysis may influence lipolytic activity by suppressing fatty acid re‑esterification.
Topics: Mice; Animals; Lipolysis; Catecholamines; Lactic Acid; 3T3-L1 Cells; Electron Transport; Adipocytes; Fatty Acids; Glucose; Adenosine Triphosphate
PubMed: 37859599
DOI: 10.3892/mmr.2023.13116 -
International Journal of Experimental... Dec 2023This study aimed to investigate the effects of mitochondrial homeostasis on lipopolysaccharide (LPS)-induced endothelial cell barrier function and the mechanisms that...
This study aimed to investigate the effects of mitochondrial homeostasis on lipopolysaccharide (LPS)-induced endothelial cell barrier function and the mechanisms that underlie these effects. Cells were treated with LPS or oligomycin (mitochondrial adenosine triphosphate synthase inhibitor) and the mitochondrial morphology, mitochondrial reactive oxygen species (mtROS), and mitochondrial membrane potential (ΔΨm) were evaluated. Moreover, the shedding of glycocalyx-heparan sulphate (HS), the levels of HS-specific degrading enzyme heparanase (HPA), and the expression of occludin and zonula occludens (ZO-1) of Tight Junctions (TJ)s, which are mediated by myosin light chain phosphorylation (p-MLC), were assessed. Examining the changes in mitochondrial homeostasis showed that adding heparinase III, which is an exogenous HPA, can destroy the integrity of glycocalyx. LPS simultaneously increased mitochondrial swelling, mtROS, and ΔΨm. Without oligomycin effects, HS, HPA levels, and p-MLC were found to be elevated, and the destruction of occludin and ZO-1 increased. Heparinase III not only damaged the glycocalyx by increasing HS shedding but also increased mitochondrial swelling and mtROS and decreased ΔΨm. Mitochondrial homeostasis is involved in LPS-induced endothelial cell barrier dysfunction by aggravating HPA and p-MLC levels. In turn, the integrated glycocalyx protects mitochondrial homeostasis.
Topics: Lipopolysaccharides; Occludin; Endothelial Cells; Tight Junctions; Oligomycins
PubMed: 37828780
DOI: 10.1111/iep.12495 -
Frontiers in Physiology 2023Mitochondrial dysfunction is linked to a variety of human diseases. Understanding the dynamic alterations in mitochondrial respiration at various stages of development...
Mitochondrial dysfunction is linked to a variety of human diseases. Understanding the dynamic alterations in mitochondrial respiration at various stages of development is important to our understanding of disease progression. Zebrafish provide a system for investigating mitochondrial function and alterations during different life stages. The purpose of this study was to investigate our ability to measure mitochondrial oxygen consumption rates in zebrafish embryos, larvae, and adults as an indicator of mitochondrial function. Basal respiration of entire zebrafish embryos (5 dpf), larvae (0.6-0.9 cm), young adults (3-month-old), and old adults (12-month-old) was measured using an Oroboros Oxygraph, with a stirrer speed of 26 rpm. For embryos and larvae, "leak" respiration (plus oligomycin), maximum respiration (plus uncoupler), non-mitochondrial respiration (plus inhibitors), and complex IV activity were also measured. To induce physical activity in adult fish, the stirrer speed was increased to 200 rpm. We demonstrate the ability to accurately measure respiration rates in zebrafish at various ages using the Oroboros Oxygraph. When comparing zebrafish embryos to larvae, embryos have a higher maximum respiration. Three-month-old zebrafish males have higher basal respiration than females, while 12-month-old zebrafish females exhibit greater rates of respiration than males and younger females. When the stirrer speed was increased, respiration rates decrease, but with differences depending on sex. This study demonstrates a simple and accessible method to assess zebrafish physiology by mitochondrial oxygen consumption measurements in an unmodified Oroboros Oxygraph. The method should facilitate studies to understand the intricate interplay between mitochondrial function, development, and aging.
PubMed: 37781232
DOI: 10.3389/fphys.2023.1272366 -
BMC Anesthesiology Sep 2023Dexamethasone (Dexa) has been recently found to exert an analgesic effect, whose action is closely related to IL-8. However, whether dexamethasone induces...
BACKGROUND
Dexamethasone (Dexa) has been recently found to exert an analgesic effect, whose action is closely related to IL-8. However, whether dexamethasone induces antinociception via glycolysis and mitochondria-related pathways is still unclear.
METHODS
Right hind paw inflammatory pain in mice was induced by intraplantar injection of Freund's Complete Adjuvant (FCA). Von Frey test was then used to measure the paw withdrawal threshold. The detection of glycolysis and mitochondrial pathway-related proteins and IL-8 were determined by Western blot and ELISA. The potential interaction between Dexa and fructose-1,6-bisphosphate (FBP, a PKM2 activator) was examined by simulation predictions using molecular docking.
RESULTS
Intrathecal administration of Dexa (20 µg/20 µL) had an obvious analgesic effect in FCA-treated mice, which was counteracted by the glycolysis inhibitor 2-deoxyglucose (2-DG, 5 mg/20 µL) or the mitochondria-related pathway inhibitor oligomycin complex (Oligo, 5 µg/20 µL). In the glycolysis pathway, Dexa decreased GLUT3 and had no impact on HIF-1α expression during FCA-induced inflammation. Additionally, Dexa further increased the PKM2 level, accompanied by the formation of hydrogen bonds between Dexa and the PKM2 activator fructose-1,6-bisphosphate (FBP). In the mitochondrial pathway, Dexa downregulated the expression of Mfn2 protein but not the PGC-1α and SIRT-1 levels in the spinal cord. Moreover, both 2-DG and Oligo decreased Mfn2 expression. Finally, IL-8 level was reduced by the single or combined administration of Dexa, 2-DG, and Oligo.
CONCLUSION
Dexa attenuated IL-8 expression via glycolysis and mitochondrial pathway-related proteins, thus mediating the analgesic effect during inflammatory pain.
Topics: Animals; Mice; Interleukin-8; Molecular Docking Simulation; Fructose; Glycolysis; Mitochondria; Dexamethasone; Analgesics
PubMed: 37723417
DOI: 10.1186/s12871-023-02277-9 -
Molecules (Basel, Switzerland) Aug 2023Polyphenols have attracted attention in the fight against antibiotic-resistant bacteria, as they show antibacterial action. Considering that polyphenols inhibit FF-ATP...
Cirsiliol and Quercetin Inhibit ATP Synthesis and Decrease the Energy Balance in Methicillin-Resistant (MRSA) and Methicillin-Resistant (MRSE) Strains Isolated from Patients.
Polyphenols have attracted attention in the fight against antibiotic-resistant bacteria, as they show antibacterial action. Considering that polyphenols inhibit FF-ATP synthase (ATP synthase) and that bacteria need a constant energy production to maintain their homeostasis, we evaluated the effect of two flavones, cirsiliol (tri-hy-droxy-6,7-dimethoxyflavone) and quercetin (3,3,4,5,7-pentahydroxyflavone), on energy production and intracellular ATP content in a methicillin-resistant (MRSA) strain and a methicillin-resistant (MRSE) strain isolated from patients, comparing the results to those obtained by treating the bacteria with oligomycin, a specific ATP synthase F moiety inhibitor. Real-time quantitative ATP synthesis and total ATP content of permeabilized Gram-positive bacteria were assayed by luminometry. The results showed that cirsiliol and quercetin inhibited ATP synthase and decreased the intracellular ATP levels in both strains, although the effect was higher in MRSE. In addition, while cirsiliol and quercetin acted immediately after the treatment, oligomycin inhibited ATP synthesis only after 30 min of incubation, suggesting that the different responses may depend on the different permeability of the bacterial wall to the three molecules. Thus, cirsiliol and quercetin could be considered potential additions to antibiotics due to their ability to target ATP synthase, against which bacteria cannot develop resistance.
Topics: Humans; Methicillin-Resistant Staphylococcus aureus; Quercetin; Staphylococcus epidermidis; Methicillin Resistance; Flavones; Polyphenols; Adenosine Triphosphate; Anti-Bacterial Agents
PubMed: 37687012
DOI: 10.3390/molecules28176183