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Scientific Reports Jun 2024We have reported that an environmental pollutant, cadmium, promotes cell death in the human renal tubular cells (RTCs) through hyperactivation of a serine/threonine...
We have reported that an environmental pollutant, cadmium, promotes cell death in the human renal tubular cells (RTCs) through hyperactivation of a serine/threonine kinase Akt. However, the molecular mechanisms downstream of Akt in this process have not been elucidated. Cadmium has a potential to accumulate misfolded proteins, and proteotoxicity is involved in cadmium toxicity. To clear the roles of Akt in cadmium exposure-induced RTCs death, we investigated the possibility that Akt could regulate proteotoxicity through autophagy in cadmium chloride (CdCl)-exposed HK-2 human renal proximal tubular cells. CdCl exposure promoted the accumulation of misfolded or damaged proteins, the formation of aggresomes (pericentriolar cytoplasmic inclusions), and aggrephagy (selective autophagy to degrade aggresome). Pharmacological inhibition of Akt using MK2206 or Akti-1/2 enhanced aggrephagy by promoting dephosphorylation and nuclear translocation of transcription factor EB (TFEB)/transcription factor E3 (TFE3), lysosomal transcription factors. TFEB or TFE3 knockdown by siRNAs attenuated the protective effects of MK2206 against cadmium toxicity. These results suggested that aberrant activation of Akt attenuates aggrephagy via TFEB or TFE3 to facilitate CdCl-induced cell death. Furthermore, these roles of Akt/TFEB/TFE3 were conserved in CdCl-exposed primary human RTCs. The present study shows the molecular mechanisms underlying Akt activation that promotes cadmium-induced RTCs death.
Topics: Humans; Proto-Oncogene Proteins c-akt; Autophagy; Basic Helix-Loop-Helix Leucine Zipper Transcription Factors; Cell Line; Cadmium; Kidney Tubules, Proximal; Phosphorylation; Cadmium Chloride; Heterocyclic Compounds, 3-Ring; Kidney Tubules
PubMed: 38914593
DOI: 10.1038/s41598-024-64579-3 -
Journal of Agricultural and Food... Jun 2024: Following spinal cord injury (SCI), autophagy plays a positive role in neuronal protection, whereas pyroptosis triggers an inflammatory response. Ginsenoside-Rh2...
: Following spinal cord injury (SCI), autophagy plays a positive role in neuronal protection, whereas pyroptosis triggers an inflammatory response. Ginsenoside-Rh2 (GRh2), known for its neuroprotective effects, is considered a promising drug. However, the exact molecular mechanisms underlying these protective effects remain unclear. : Explore the therapeutic value of GRh2 in SCI and its potential mechanisms of action. : An SCI mouse model was established, followed by random grouping and drug treatments under different conditions. Subsequently, the functional recovery of SCI mice after GRh2 treatment was assessed using hematoxylin and eosin, Masson's trichrome, and Nissl staining, footprint analysis, Basso Mouse Scale scoring, and inclined plane tests. The expression levels of relevant indicators in the mice were detected using Western blotting, immunofluorescence, and a quantitative polymerase chain reaction. Network pharmacology analysis was used to identify the relevant signaling pathways through which GRh2 exerts its therapeutic effects. : GRh2 promoted functional recovery after SCI. GRh2 significantly inhibits pyroptosis by enhancing autophagy in SCI mice. Simultaneously, the neuroprotective effect of GRh2, achieved through the inhibition of pyroptosis, is partially reversed by 3-methyladenine, an autophagy inhibitor. Additionally, the increase in autophagy induced by GRh2 is mediated by the promotion of transcription factor EB (TFEB) nuclear translocation and dephosphorylation. Partial attenuation of the protective effects of GRh2 was observed after TFEB knockdown. Additionally, GRh2 can modulate the activity of TFEB in mice post-SCI through the EGFR-MAPK signaling pathway, and NSC228155 (an EGFR activator) can partially reverse the effect of GRh2 on the EGFR-MAPK signaling pathway. : GRh2 improves functional recovery after SCI by upregulating TFEB-mediated autophagic flux and inhibiting pyroptosis, indicating its potential clinical applicability.
PubMed: 38907713
DOI: 10.1021/acs.jafc.4c02379 -
Kidney International Jul 2024
Corrigendum to "Phosphoglycerate mutase 5 initiates inflammation in acute kidney injury by triggering mitochondrial DNA release by dephosphorylating the pro-apoptotic protein Bax." Kidney International 2023;103:115-133.
PubMed: 38906651
DOI: 10.1016/j.kint.2024.04.006 -
Journal of Cell Science Jun 2024PTPRK is a receptor tyrosine phosphatase linked to the regulation of growth factor signalling and tumour suppression. It is stabilized at the plasma membrane by trans...
PTPRK is a receptor tyrosine phosphatase linked to the regulation of growth factor signalling and tumour suppression. It is stabilized at the plasma membrane by trans homophilic interactions upon cell-cell contact. It regulates cell-cell adhesion, but is also reported to regulate numerous cancer-associated signalling pathways. However, its signalling mechanism remains to be determined. Here, we find that PTPRK regulates cell adhesion signalling, suppresses invasion and promotes collective, directed migration in colorectal cancer cells. In vivo, PTPRK supports recovery from inflammation-induced colitis. In addition, we confirm that PTPRK functions as a tumour suppressor in the mouse colon and in colorectal cancer xenografts. PTPRK regulates growth factor and adhesion signalling, and suppresses epithelial to mesenchymal transition (EMT). Contrary to the prevailing notion that PTPRK directly dephosphorylates EGFR, we find that PTPRK regulation of both EGFR and EMT is independent of its catalytic function. This suggests that additional adaptor and scaffold functions are important features of PTPRK signalling.
PubMed: 38904097
DOI: 10.1242/jcs.261914 -
BioRxiv : the Preprint Server For... May 2024The bone-resorbing activity of osteoclasts plays a critical role in the life-long remodeling of our bones that is perturbed in many bone loss diseases. Multinucleated...
The bone-resorbing activity of osteoclasts plays a critical role in the life-long remodeling of our bones that is perturbed in many bone loss diseases. Multinucleated osteoclasts are formed by the fusion of precursor cells, and larger cells - generated by an increased number of cell fusion events - have higher resorptive activity. We find that osteoclast fusion and bone-resorption are promoted by reactive oxygen species (ROS) signaling and by an unconventional low molecular weight species of La protein, located at the osteoclast surface. Here, we develop the hypothesis that La's unique regulatory role in osteoclast multinucleation and function is controlled by a ROS switch in La trafficking. Using antibodies that recognize reduced or oxidized species of La, we find that differentiating osteoclasts enrich an oxidized species of La at the cell surface, which is distinct from the reduced La species conventionally localized within cell nuclei. ROS signaling triggers the shift from reduced to oxidized La species, its dephosphorylation and delivery to the surface of osteoclasts, where La promotes multinucleation and resorptive activity. Moreover, intracellular ROS signaling in differentiating osteoclasts oxidizes critical cysteine residues in the C-terminal half of La, producing this unconventional La species that promotes osteoclast fusion. Our findings suggest that redox signaling induces changes in the location and function of La and may represent a promising target for novel skeletal therapies.
PubMed: 38903088
DOI: 10.1101/2024.05.02.592254 -
Vascular Pharmacology Jun 2024Increased proliferation and reduced apoptosis of pulmonary artery smooth muscle cells (PASMCs) is recognised as a universal hallmark of pulmonary arterial hypertension...
Increased proliferation and reduced apoptosis of pulmonary artery smooth muscle cells (PASMCs) is recognised as a universal hallmark of pulmonary arterial hypertension (PAH), in part related to the association with reduced pyruvate dehydrogenase (PDH) activity, resulting in decreased oxidative phosphorylation of glucose and increased aerobic glycolysis (Warburg effect). Perhexiline is a well-recognised carnitine palmitoyltransferase-1 (CPT1) inhibitor used in cardiac diseases, which reciprocally increases PDH activity, but is associated with variable pharmacokinetics related to polymorphic variation of the cytochrome P450-2D6 (CYP2D6) enzyme, resulting in the risk of neuro and hepatotoxicity in 'slow metabolisers' unless blood levels are monitored and dose adjusted. We have previously reported that a novel perhexiline fluorinated derivative (FPER-1) has the same therapeutic profile as perhexiline but is not metabolised by CYP2D6, resulting in more predictable pharmacokinetics than the parent drug. We sought to investigate the effects of perhexiline and FPER-1 on PDH flux in PASMCs from patients with PAH. We first confirmed that PAH PASMCs exhibited increased cell proliferation, enhanced phosphorylation of AKT, ERK 1/2 and PDH-E1α, indicating a Warburg effect when compared to healthy PASMCs. Pre-treatment with perhexiline or FPER-1 significantly attenuated PAH PASMC proliferation in a concentration-dependent manner and suppressed the activation of the AKT but had no effect on the ERK pathway. Perhexiline and FPER-1 markedly activated PDH (seen as dephosphorylation of PDH-E1α), reduced glycolysis, and upregulated mitochondrial respiration in these PAH PASMCs as detected by Seahorse analysis. However, both perhexiline and FPER-1 did not induce apoptosis as measured by caspase 3/7 activity. We show for the first time that both perhexiline and FPER-1 may represent therapeutic agents for reducing cell proliferation in human PAH PASMCs, by reversing Warburg physiology.
PubMed: 38901807
DOI: 10.1016/j.vph.2024.107399 -
The Science of the Total Environment Jun 2024The ubiquity and persistence of organophosphate esters (OPEs) and heavy metal (HMs) pose global environmental risks. This study explored tris(2-chloroisopropyl)phosphate...
The ubiquity and persistence of organophosphate esters (OPEs) and heavy metal (HMs) pose global environmental risks. This study explored tris(2-chloroisopropyl)phosphate (TCPP) biomineralization coupled to lead (Pb) biostabilization driven by denitrifying bacteria (DNB). The domesticated DNB achieved synergistic bioremoval of TCPP and Pb in the batch bioreactor (efficiency: 98 %).TCPP mineralized into PO and Cl, and Pb precipitated with PO. The TCPP-degrading/Pb-resistant DNB: Achromobacter, Pseudomonas, Citrobacter, and Stenotrophomonas, dominated the bacterial community, and synergized TCPP biomineralization and Pb biostabilization. Metagenomics and metaproteomics revealed TCPP underwent dechlorination, hydrolysis, the TCA cycle-based dissimilation, and assimilation; Pb was detoxified via bioprecipitation, bacterial membrane biosorption, EPS biocomplexation, and efflux out of cells. TCPP, as an initial donor, along with NO, as the terminal acceptor, formed a respiratory redox as the primary energy metabolism. Both TCPP and Pb can stimulate phosphatase expression, which established the mutual enhancements between their bioconversions by catalyzing TCPP dephosphorylation and facilitating Pb bioprecipitation. TCPP may alleviate the Pb-induced oxidative stress by aiding protein phosphorylation. 80 % of Pb converted into crystalized pyromorphite. These results provide the mechanistic foundations and help develop greener strategies for synergistic bioremediation of OPEs and HMs.
PubMed: 38901584
DOI: 10.1016/j.scitotenv.2024.173927 -
Plant & Cell Physiology Jun 2024BRI1-EMS Suppressor 1 (BES1) and Brassinazole resistant 1 (BZR1) are two highly similar master transcription factors of the brassinosteroid (BR) signaling pathway that...
BRI1-EMS Suppressor 1 (BES1) and Brassinazole resistant 1 (BZR1) are two highly similar master transcription factors of the brassinosteroid (BR) signaling pathway that regulate a variety of plant growth and development processes as well as stress responses. Previous genetic and biochemical analyses have established a complex regulatory network to control the two transcription factors. This network includes coordination with other transcription factors and interactors, multiple post-translational modifications (PTMs), and differential subcellular localizations. In this review, we systematically detail the functions and regulatory mechanisms of various PTMs: phosphorylation/dephosphorylation, ubiquitination/deubiquitination, SUMOylation/deSUMOylation, oxidation/reduction, in regulating the subcellular localization, protein stability, and the transcriptional activity of BES1/BZR1. We also discuss the current knowledge about the BES1/BZR1-interactors mediating the dynamic nucleocytoplasmic shuttling of BES1 and BZR1.
PubMed: 38896040
DOI: 10.1093/pcp/pcae066 -
Frontiers in Endocrinology 2024Gonadotropin-releasing hormone (GnRH) is a key stimulator for gonadotropin secretion in the pituitary and its pivotal role in reproduction is well conserved in...
Differential involvement of cAMP/PKA-, PLC/PKC- and Ca/calmodulin-dependent pathways in GnRH-induced prolactin secretion and gene expression in grass carp pituitary cells.
Gonadotropin-releasing hormone (GnRH) is a key stimulator for gonadotropin secretion in the pituitary and its pivotal role in reproduction is well conserved in vertebrates. In fish models, GnRH can also induce prolactin (PRL) release, but little is known for the corresponding effect on PRL gene expression as well as the post-receptor signalling involved. Using grass carp as a model, the functional role of GnRH and its underlying signal transduction for PRL regulation were examined at the pituitary level. Using laser capture microdissection coupled with RT-PCR, GnRH receptor expression could be located in carp lactotrophs. In primary cell culture prepared from grass carp pituitaries, the native forms of GnRH, GnRH2 and GnRH3, as well as the GnRH agonist [D-Arg, Pro, NEt]-sGnRH were all effective in elevating PRL secretion, PRL mRNA level, PRL cell content and total production. In pituitary cells prepared from the rostral pars distalis, the region in the carp pituitary enriched with lactotrophs, GnRH not only increased cAMP synthesis with parallel CREB phosphorylation and nuclear translocation but also induced a rapid rise in cytosolic Ca by Ca influx via L-type voltage-sensitive Ca channel (VSCC) with subsequent CaM expression and NFAT dephosphorylation. In carp pituitary cells prepared from whole pituitaries, GnRH-induced PRL secretion was reduced/negated by inhibiting cAMP/PKA, PLC/PKC and Ca/CaM/CaMK-II pathways but not the signalling events via IP and CaN/NFAT. The corresponding effect on PRL mRNA expression, however, was blocked by inhibiting cAMP/PKA/CREB/CBP and Ca/CaM/CaN/NFAT signalling but not PLC/IP/PKC pathway. At the pituitary cell level, activation of cAMP/PKA pathway could also induce CaM expression and Ca influx via VSCC with parallel rises in PRL release and gene expression in a Ca/CaM-dependent manner. These findings, as a whole, suggest that the cAMP/PKA-, PLC/PKC- and Ca/CaM-dependent cascades are differentially involved in GnRH-induced PRL secretion and PRL transcript expression in carp lactotrophs. During the process, a functional crosstalk between the cAMP/PKA- and Ca/CaM-dependent pathways may occur with PRL release linked with CaMK-II and PKC activation and PRL gene transcription caused by nuclear action of CREB/CBP and CaN/NFAT signalling.
Topics: Animals; Carps; Gonadotropin-Releasing Hormone; Prolactin; Pituitary Gland; Protein Kinase C; Cyclic AMP-Dependent Protein Kinases; Calcium; Type C Phospholipases; Cyclic AMP; Signal Transduction; Calmodulin; Cells, Cultured; Gene Expression
PubMed: 38894746
DOI: 10.3389/fendo.2024.1399274 -
British Journal of Cancer Jun 2024The combined use of CDK4/6 inhibitors and mTOR inhibitors has achieved some clinical success in ccRCC. Exploring the underlying mechanism of the CDK4/6 pathway in cancer...
BACKGROUND
The combined use of CDK4/6 inhibitors and mTOR inhibitors has achieved some clinical success in ccRCC. Exploring the underlying mechanism of the CDK4/6 pathway in cancer cells and the drug interactions of CDK4/6 inhibitors in combination therapy could help identify new therapeutic strategies for ccRCC. Notably, CDK4/6 inhibitors inactivate the mTOR pathway by increasing the protein levels of TSC1, but the mechanism by which CDK4/6 inhibitors regulate TSC1 is still unclear.
METHODS
Mass spectrometry analysis, coimmunoprecipitation analysis, GST pull-down assays, immunofluorescence assays, Western blot analysis and RT‒qPCR analysis were applied to explore the relationships among CDK4, RNF26 and TSC1. Transwell assays, tube formation assays, CCK-8 assays, colony formation assays and xenograft assays were performed to examine the biological role of RNF26 in renal cancer cells.TCGA-KIRC dataset analysis and RT‒qPCR analysis were used to examine the pathways affected by RNF26 silencing.
RESULTS
CDK4/6 inhibitors stabilized TSC1 in cancer cells. We showed that CDK4 enhances the interaction between TSC1 and RNF26 and that RNF26 activates the mTOR signaling pathway in ccRCC, contributes to ccRCC progression and angiogenesis, and promotes tumorigenesis. We then found that RNF26 functions as an E3 ligase of TSC1 to regulate CDK4-induced TSC1. This finding suggested that RNF26 promotes ccRCC progression and angiogenesis to some extent by negatively regulating TSC1.
CONCLUSION
Our results revealed a novel CDK4/RNF26/TSC1 axis that regulates the anticancer efficacy of CDK4/6 inhibitors and mTOR inhibitors in ccRCC.
PubMed: 38890443
DOI: 10.1038/s41416-024-02750-3