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European Journal of Pharmacology Jun 2024Dihydromyricetin (DHM) is a flavonoid from vine tea with broad pharmacological benefits, which improve inflammation by blocking the NF-κB pathway. A growing body of...
Dihydromyricetin (DHM) is a flavonoid from vine tea with broad pharmacological benefits, which improve inflammation by blocking the NF-κB pathway. A growing body of research indicates that chronic kidney inflammation is vital to the pathogenesis of diabetic renal fibrosis. Sphingosine kinase-1 (SphK1) is a key regulator of diabetic renal inflammation, which triggers the NF-κB pathway. Hence, we evaluated whether DHM regulates diabetic renal inflammatory fibrosis by acting on SphK1. Here, we demonstrated that DHM effectively suppressed the synthesis of fibrotic and inflammatory adhesion factors like ICAM-1, and VCAM-1 in streptozotocin-treated high-fat diet-induced diabetic mice and HG-induced glomerular mesangial cells (GMCs). Moreover, DHM significantly suppressed NF-κB pathway activation and reduced SphK1 activity and protein expression under diabetic conditions. Mechanistically, the results of molecular docking, molecular dynamics simulation, and cellular thermal shift assay revealed that DHM stably bound to the binding pocket of SphK1, thereby reducing sphingosine-1-phosphate content and SphK1 enzymatic activity, which ultimately inhibited NF-κB DNA binding, transcriptional activity, and nuclear translocation. In conclusion, our data suggested that DHM inhibited SphK1 phosphorylation to prevent NF-κB activation thus ameliorating diabetic renal fibrosis. This supported the clinical use and further drug development of DHM as a potential candidate for treating diabetic renal fibrosis.
PubMed: 38945289
DOI: 10.1016/j.ejphar.2024.176799 -
Biochimica Et Biophysica Acta.... Jun 2024PtdIns and its phosphorylated derivatives, the phosphoinositides, are the biochemical components of a major pathway of intracellular signaling in all eukaryotic cells....
PtdIns and its phosphorylated derivatives, the phosphoinositides, are the biochemical components of a major pathway of intracellular signaling in all eukaryotic cells. These lipids are few in terms of cohort of unique positional isomers, and are quantitatively minor species of the bulk cellular lipidome. Nevertheless, phosphoinositides regulate an impressively diverse set of biological processes. It is from that perspective that perturbations in phosphoinositide-dependent signaling pathways are increasingly being recognized as causal foundations of many human diseases - including cancer. Although phosphatidylinositol transfer proteins (PITPs) are not enzymes, these proteins are physiologically significant regulators of phosphoinositide signaling. As such, PITPs are conserved throughout the eukaryotic kingdom. Their biological importance notwithstanding, PITPs remain understudied. Herein, we review current information regarding PITP biology primarily focusing on how derangements in PITP function disrupt key signaling/developmental pathways and are associated with a growing list of pathologies in mammals.
PubMed: 38945251
DOI: 10.1016/j.bbalip.2024.159529 -
Molecular Genetics and Metabolism Jun 2024The malate aspartate shuttle (MAS) plays a pivotal role in transporting cytosolic reducing equivalents - electrons - into the mitochondria for energy conversion at the... (Review)
Review
The malate aspartate shuttle (MAS) plays a pivotal role in transporting cytosolic reducing equivalents - electrons - into the mitochondria for energy conversion at the electron transport chain (ETC) and in the process of oxidative phosphorylation. The MAS consists of two pairs of cytosolic and mitochondrial isoenzymes (malate dehydrogenases 1 and 2; and glutamate oxaloacetate transaminases 1 and 2) and two transporters (malate-2-oxoglutarate carrier and aspartate glutamate carrier (AGC), the latter of which has two tissue-dependent isoforms AGC1 and AGC2). While the inner mitochondrial membrane is impermeable to NADH, the MAS forms one of the main routes for mitochondrial electron uptake by promoting uptake of malate. Inherited bi-allelic pathogenic variants in five of the seven components of the MAS have been described hitherto and cause a wide spectrum of symptoms including early-onset epileptic encephalopathy. This review provides an overview of reported patients suffering from MAS deficiencies. In addition, we give an overview of diagnostic procedures and research performed on patient-derived cellular models and tissues. Current cellular models are briefly discussed and novel ways to achieve a better understanding of MAS deficiencies are highlighted.
PubMed: 38945121
DOI: 10.1016/j.ymgme.2024.108520 -
Redox Biology Jun 2024Tumors develop in an oxidative environment characterized by peroxynitrite production and downstream protein tyrosine (Y) nitration. We showed that tyrosine nitration...
Tumors develop in an oxidative environment characterized by peroxynitrite production and downstream protein tyrosine (Y) nitration. We showed that tyrosine nitration supports schwannoma cell proliferation and regulates cell metabolism in the inheritable tumor disorder NF2-related Schwannomatosis (NF2-SWN). Here, we identified the chaperone Heat shock protein 90 (Hsp90) as the first nitrated protein that acts as a metabolic switch to promote schwannoma cell proliferation. Doubling the endogenous levels of nitrated Hsp90 in schwannoma cells or supplementing nitrated Hsp90 into normal Schwann cells increased their proliferation. Metabolically, nitration on either Y33 or Y56 conferred Hsp90 distinct functions; nitration at Y33 (Hsp90) down-regulated mitochondrial oxidative phosphorylation, while nitration at Y56 (Hsp90) increased glycolysis by activating the purinergic receptor P2X7 in both schwannoma and normal Schwann cells. Hsp90 and Hsp90 showed differential subcellular and spatial distribution corresponding with their metabolic and proliferative functions in schwannoma three-dimensional cell culture models. Collectively, these results underscore the role of tyrosine nitration as a post-translational modification regulating critical cellular processes. Nitrated proteins, particularly nitrated Hsp90, emerge as a novel category of tumor-directed therapeutic targets.
PubMed: 38945076
DOI: 10.1016/j.redox.2024.103249 -
International Immunopharmacology Jun 2024Tuberculosis, caused by Mycobacterium tuberculosis (Mtb), still ranks among the leading causes of annual human death by infectious disease. Mtb has developed several...
Tuberculosis, caused by Mycobacterium tuberculosis (Mtb), still ranks among the leading causes of annual human death by infectious disease. Mtb has developed several strategies to survive for years at a time within the host despite the presence of a robust immune response, including manipulating the progression of the inflammatory response and forming granulomatous lesions. Here we demonstrate that IQGAP1, a highly conserved scaffolding protein, compartmentalizes and coordinates multiple signaling pathways in macrophages infected with Mycobacterium marinum (Mm or M.marinum), the closest relative of Mtb. Upregulated IQGAP1 ultimately suppresses TNF-α production by repressing the MKK3 signal and reducing NF-κBp65 translocation, deactivating the p38MAPK pathway. Accordingly, IQGAP1 silencing and overexpression significantly alter p38MAPK activity by modulating the production of phosphorylated MKK3 during mycobacterial infection. Pharmacological inhibition of IQGAP1-associated microtubule assembly not only alleviates tissue damage caused by M.marinum infection but also significantly decreases the production of VEGF-a critical player for granuloma-associated angiogenesis during pathogenic mycobacterial infection. Similarly, IQGAP1 silencing in Mm-infected macrophages diminishes VEGF production, while IQGAP1 overexpression upregulates VEGF. Our data indicate that mycobacteria induce IQGAP1 to hijack NF-κBp65 activation, preventing the expression of proinflammatory cytokines as well as promoting VEGF production during infection and granuloma formation. Thus, therapies targeting host IQGAP1 may be a promising strategy for treating tuberculosis, particularly in drug-resistant diseases.
PubMed: 38944950
DOI: 10.1016/j.intimp.2024.112549 -
Chemico-biological Interactions Jun 2024Dibutyl phthalate (DBP) is widely used in many consumer and personal care products. Here, we report vascular endothelial response to DBP in three different exposure...
Dibutyl phthalate (DBP) is widely used in many consumer and personal care products. Here, we report vascular endothelial response to DBP in three different exposure scenarios: after short-term exposure (24 h) of human endothelial cells (ECs) EA.hy926 to 10, 10, and 10 M DBP, long-term exposure (12 weeks) of EA.hy926 cells to 10, 10, and 10 M DBP, and exposure of rats (28 and 90 days) to 100, 500, and 5000 mg DBP/kg food. We examined different vascular functions such as migration of ECs, adhesion of ECs to the extracellular matrix, tube formation, the morphology of rat aorta, as well as several signaling pathways involved in controlling endothelial function. Short-term in vitro exposure to DBP increased migration of ECs through G protein-coupled estrogen receptor, extracellular signal-regulated kinase 1/2, and nitric oxide (NO) signaling and decreased adhesion to gelatin. Long-term in vitro exposure to DBP transiently increased EC migration and had a bidirectional effect on EC adhesion to gelatin and tube formation. These effects were accompanied by a sustained increase in NO production and endothelial NO synthase (eNOS) and Akt activity. In vivo, exposure to DBP for 90 days decreased the aortic wall-to-lumen ratio and increased eNOS and Akt phosphorylation in ECs of rat aorta. This comparative investigation has shown that exposure to DBP may affect vascular function by altering EC migration, adhesion to gelatin, and tube formation after short- and long-term in vitro exposure and by decreasing the aortic wall-to-lumen ratio in vivo. The eNOS-NO and Akt signaling could be important in mediating the effects of DBP in long-term exposure scenarios.
PubMed: 38944327
DOI: 10.1016/j.cbi.2024.111120 -
Journal of Advanced Research Jun 2024The immunosuppressive capacity of mesenchymal stem cells (MSCs) is dependent on the "license" of several pro-inflammatory factors to express immunosuppressive molecular...
INTRODUCTION
The immunosuppressive capacity of mesenchymal stem cells (MSCs) is dependent on the "license" of several pro-inflammatory factors to express immunosuppressive molecular profiles, which determines the therapeutic efficacy of MSCs in immune-mediated inflammatory diseases. Of those, interferon-γ (IFN-γ) is a key inducer for the expression of immunosuppressive molecular profiles; however, the mechanism underlying this effect is unknown.
OBJECTIVES
To elucidate the regulation mechanism and biological functions of N-methyladenosine (mA) modification in the immunosuppressive functions by the IFN-γ-licensing MSCs.
METHODS
Epitranscriptomic microarray analysis and MeRIP-qPCR assay were performed to identify the regulatory effect of WTAP in the IFN-γ-licensing MSCs. RIP-qPCR, western blot, qRT-PCR and RNA stability assays were used to determine the regulation of WTAP/mA/YTHDF1 signaling axis in the expression of immunosuppressive molecules. Further, functional capacity of T cells was tested using flow cytometry, and both DSS-induced colitis mice and CIA mice were constructed to clarify the effect of WTAP and YTHDF1 in MSC-mediated immunosuppression.
RESULTS
We identified that IFN-γ increased the mA methylation levels of immunosuppressive molecules, while WTAP deficiency abolished the IFN-γ-induced promotion of mA modification. IFN-γ activated ERK signaling, which induced WTAP phosphorylation. Additionally, the stabilization of WTAP post-transcriptionally increased the mRNA expression of immunosuppressive molecules (IDO1, PD-L1, ICAM1, and VCAM1) in an mA-YTHDF1-dependent manner; this effect further impacted the immunosuppressive capacity of IFN-γ licensing MSCs on activated T cells. Notably, WTAP/YTHDF1 overexpression enhanced the therapeutic efficacy of IFN-γ licensing MSCs and restructures the ecology of inflammation in both colitis and arthritis models.
CONCLUSION
Our results showed that mA modification of IDO1, PD-L1, ICAM1, and VCAM1 mRNA mediated by WTAP-YTHDF1 is involved in the regulation of IFN-γ licensing MSCs immunosuppressive abilities, and shed a light to enhance the clinical therapeutic potential of IFN-γ-licensing MSCs.
PubMed: 38944238
DOI: 10.1016/j.jare.2024.06.019 -
Pharmacological Research Jun 2024The global incidence of cardiac diseases is increasing, imposing a substantial socioeconomic burden on healthcare systems. The pathogenesis of cardiovascular disease is... (Review)
Review
The global incidence of cardiac diseases is increasing, imposing a substantial socioeconomic burden on healthcare systems. The pathogenesis of cardiovascular disease is complex and not fully understood, and the physiological function of the heart is inextricably linked to well-regulated cardiac muscle movement. Myosin light chain kinase (MLCK) is essential for myocardial contraction and diastole, cardiac electrophysiological homeostasis, vasoconstriction of vascular nerves and blood pressure regulation. In this sense, MLCK appears to be an attractive therapeutic target for cardiac diseases. MLCK participates in myocardial cell movement and migration through diverse pathways, including regulation of calcium homeostasis, activation of myosin light chain phosphorylation, and stimulation of vascular smooth muscle cell contraction or relaxation. Recently, phosphorylation of myosin light chains has been shown to be closely associated with the activation of myocardial exercise signaling, and MLCK mediates systolic and diastolic functions of the heart through the interaction of myosin thick filaments and actin thin filaments. It works by upholding the integrity of the cytoskeleton, modifying the conformation of the myosin head, and modulating innervation. MLCK governs vasoconstriction and diastolic function and is associated with the activation of adrenergic and sympathetic nervous systems, extracellular transport, endothelial permeability, and the regulation of nitric oxide and angiotensin II. Additionally, MLCK plays a crucial role in the process of cardiac aging. Multiple natural products/phytochemicals and chemical compounds, such as quercetin, cyclosporin, and ML-7 hydrochloride, have been shown to regulate cardiomyocyte MLCK. The MLCK-modifying capacity of these compounds should be considered in designing novel therapeutic agents. This review summarizes the mechanism of action of MLCK in the cardiovascular system and the therapeutic potential of reported chemical compounds in cardiac diseases by modifying MLCK processes.
PubMed: 38944220
DOI: 10.1016/j.phrs.2024.107276 -
The Journal of Biological Chemistry Jun 2024In the Neurospora circadian system, the White Collar Complex (WCC) formed by WC-1 and WC-2 drives expression of the frequency (frq) gene whose product FRQ feedbacks to...
In the Neurospora circadian system, the White Collar Complex (WCC) formed by WC-1 and WC-2 drives expression of the frequency (frq) gene whose product FRQ feedbacks to inhibit transcriptional activity of WCC. Phosphorylation of WCC has been extensively studied, but the extent and significance of other post-translational modifications (PTM) has been poorly studied. To this end, we used mass-spectrometry to study alkylation sites on WCC, resulting in discovery of nine acetylation sites. Mutagenesis analysis showed most of the acetylation events individually do not play important roles in period determination. Moreover, mutating all the lysines falling in either half of WC-1 or all the lysine residues in WC-2 to arginines did not abolish circadian rhythms. In addition, we also found nine mono-methylation sites on WC-1, but like acetylation, individual ablation of most of the mono-methylation events did not result in a significant period change. Taken together, the data here suggest that acetylation or mono-methylation on WCC is not a determinant of the pace of the circadian feedback loop. The finding is consistent with a model in which repression of WCC's circadian activity is controlled mainly by phosphorylation. Interestingly, light-induced expression of some light-responsive genes has been modulated in certain wc-1 acetylation mutants, suggesting that WC-1 acetylation events differentially regulate light responses.
PubMed: 38944116
DOI: 10.1016/j.jbc.2024.107508 -
International Journal of Biological... Jun 2024Pleurotus ostreatus is one of the most cultivated edible fungi worldwide, but its lignocellulose utilization efficiency is relatively low (<50 %), which eventually...
Pleurotus ostreatus is one of the most cultivated edible fungi worldwide, but its lignocellulose utilization efficiency is relatively low (<50 %), which eventually affects the biological efficiency of P. ostreatus. Improving cellulase production and activity will contribute to enhancing the lignocellulose-degrading capacity of P. ostreatus. AMP-activated/Snf1 protein kinase plays important roles in regulating carbon and energy metabolism. The Snf1 homolog (PoSnf1) in P. ostreatus was obtained and analyzed using bioinformatics. The cellulose response of PoSnf1, the effect of the phosphorylation level of PoSnf1 on the expression of cellulose degradation-related genes, the putative proteins that interact with the phosphorylated PoSnf1 (P-PoSnf1), the cellobiose transport function of two sugar transporters (STP1 and STP2), and the interactions between PoSnf1 and STP1/STP2 were studied in this research. We found that cellulose treatment improved the phosphorylation level of PoSnf1, which further affected cellulase activity and the expression of most cellulose degradation-related genes. A total of 1, 024 proteins putatively interacting with P-PoSnf1 were identified, and they were enriched mainly in the substances transport and metabolism. Most of the putative cellulose degradation-related protein-coding genes could respond to cellulose. Among the P-PoSnf1-interacting proteins, the functions of two sugar transporters (STP1 and STP2) were further studied, and the results showed that both could transport cellobiose and were indirectly regulated by P-PoSnf1, and that STP2 could directly interact with PoSnf1. The results of this study indicated that PoSnf1 plays an important role in regulating the expression of cellulose degradation genes possibly by affecting cellobiose transport.
PubMed: 38944091
DOI: 10.1016/j.ijbiomac.2024.133503