Dual-specificity Phosphatase Research Articles

Neuronal Dual-Specificity Phosphatase 26 Inhibition via Reactive-Oxygen-Species Responsive Mesoporous-Silica-Loaded Hydrogel for Spinal Cord Injury Repair.

Spinal cord injury (SCI) remains a formidable challenge in biomedical research, as the silencing of intrinsic regenerative signals in most spinal neurons results in an inability to reestablish neural circuits. In this study, we found that neurons with low axonal regeneration after SCI showed decreased extracellular signal-regulated kinase (ERK) phosphorylation levels. However, the expression of dual specificity phosphatase 26 (DUSP26)─which negatively regulates ERK phosphorylation─was reduced considerably in neurons undergoing spontaneous axonal regeneration. Therefore, we developed a system named F10@MS@UV-HG that integrated a DUSP26-specific inhibitor into reactive oxygen species-responsive nanoparticles and embedded them in photosensitive hydrogels. This system effectively downregulated DUSP26 expression in primary neurons and enhanced ERK phosphorylation, ultimately promoting axonal outgrowth. When transplanted into an SCI mouse model, the system achieved sustained drug release, specifically targeting the DUSP26/ERK/ELK1 pathway in the spinal neurons and facilitating short-term axonal regeneration. Additionally, long-term repair effects─including improved myelination and enhanced motor function─were evident in the SCI mice transplanted with F10@MS@UV-HG. The results suggested that activating ERK signaling by modulating DUSP26 expression in neurons after SCI could effectively promote axonal regeneration and functional recovery. Thus, the developed F10@MS@UV-HG system exhibits enormous potential as a therapeutic approach for patients with SCI.

Intercellular TIMP-1-CD63 signaling directs the evolution of immune escape and metastasis in KRAS-mutated pancreatic cancer cells

Background and aimsOncogenic KRAS mutations are present in approximately 90% of pancreatic ductal adenocarcinoma (PDAC). However, Kras mutation alone is insufficient to transform precancerous cells into metastatic PDAC. This study investigates how KRAS-mutated epithelial cells acquire the capacity to escape senescence or even immune clearance, thereby progressing to advanced PDAC.MethodsSingle-cell RNA sequencing and analysis of primary PDAC tumors were conducted. Genetically engineered pancreas-specific Kras-mutated, dual specificity phosphatase-2 (Dusp2) knockout mouse models were established. Human and mouse primary pancreatic cancer cell lines were used for in vitro assessment of cancer characteristics. Tumor progression was studied via pancreas orthotopic and portal vein injection in the immune-competent mice. Clinical relevance was validated by digital spatial transcriptomic analysis of PDAC tumors.ResultsKras mutation induces the formation of pancreatic intraepithelial neoplasia (PanIN), these lesions also exhibit significant apoptotic signals. Single-cell RNA sequencing identified a subset of ERKactiveDUSP2low cells continuing to expand from early to advanced stage PDAC. In vitro and in vivo studies reveal that early infiltrating macrophage-derived tissue inhibitor of metallopeptidase 1 (TIMP-1) is the key factor in maintaining the ERKactiveDUSP2low cell population in a CD63-dependent manner. The ERKactiveDUSP2low cancer cells further exacerbate macrophage-mediated cancer malignancy, including loss of epithelial trait, increased lymphangiogenesis, and immune escape. Digital spatial profiling analysis of PDAC samples demonstrates the colocalization of TIMP-1high macrophages and CD63high cancer cells. The presence of TIMP-1high macrophages and CD63high epithelial cells correlates with poor prognosis in PDAC.ConclusionsOur study reveals the vicious cycle between early infiltrating macrophages and pancreatic cancer cells, providing a mechanistic insight into the dynamic regulation directing pancreatic cancer progression.

DUSP12 promotes cell cycle progression and protects cells from cell death by regulating ZPR9.

Protein phosphatases are critical for regulating cell signaling, cell cycle, and cell fate decisions, and their dysregulation leads to an array of human diseases like cancer. The dual specificity phosphatases (DUSPs) have emerged as important factors driving tumorigenesis and cancer therapy resistance. DUSP12 is a poorly characterized atypical DUSP widely conserved throughout evolution. Although no direct substrate has been firmly established, DUSP12 that has been implicated in protecting cells from stress, regulating ribosomal biogenesis, and modulating cellular DNA content. In this study, we used affinity- and proximity-based biochemical purification approaches coupled to mass spectrometry to identify the zinc finger protein ZPR9 as a novel DUSP12 interactor, which was validated by in-cell and in-vitro IP assays. Interestingly, ZPR9 binds to the unique zinc-binding domain of DUSP12, which previous reports indicated was important for many of DUSP12's functions within the cell. Prior studies had implicated ZPR9 as a modulator of apoptosis, but it remained unclear if and how ZPR9 participated in the cell cycle and, more so, how it promoted cell death. Using mass spectrometry analyses, we found that overexpression of DUSP12 promoted de-phosphorylation of ZPR9 at Ser143. Overexpression of ZPR9, but not Ser143 phosphomimetic and phosphorylation-deficient mutants, led to an increase in pre-metaphase mitotic defects while knockdown of DUSP12 also showed mitotic defects in metaphase. Furthermore, knockdown of DUSP12 promoted, while knockdown of ZPR9 suppressed, stress-induced apoptosis. Our results support a model where DUSP12 protects cells from stress-induced apoptosis by promoting de-phosphorylation of ZPR9.

Bioinformatic Analysis for Exploring Target Genes and Molecular Mechanisms of Cadmium-Induced Nonalcoholic Fatty Liver Disease and Targeted Drug Prediction.

Cadmium (Cd) is a widely available metal that has been found to have a role in causing nonalcoholic fatty liver disease (NAFLD). However, the detailed toxicological targets and mechanisms by which Cd causes NAFLD are unknown. Therefore, the present work aims to reveal the main targets of action, cellular processes, and molecular pathways by which cadmium causes NAFLD. As shown in the bioinformatics analysis, there were 74 main targets of action for cadmium-induced NAFLD, hemopoietic cell kinase (HCK), EPH receptor A2 (EPHA2), MYC proto-oncogene (MYC), lysyl oxidase (LOX), dipeptidyl peptidase 7 (DPP7), nuclear factor erythroid 2-related factor 2 (NFE2L2), dual specificity phosphatase 6 (DUSP6), CD2 cytoplasmic tail binding protein 2 (CD2BP2), notch receptor 3 (NOTCH3), and phospholipase A2 group IVA (PLA2G4A) were screened as core genes. Testing these core genes in other databases, three differentially expressed genes, HCK, MYC, and DUSP6 were verified and used as targets for drug prediction in DsigDB; decitabine and retinoic acid were screened as potential therapeutic drugs for NAFLD based on the p-value and the combined score. The results of molecular docking showed that the predicted drugs can bind well to the core targets. In conclusion, cadmium is associated with NAFLD; the identified cadmium-toxicity targets, HCK, MYC, and DUSP6, may serve as biomarkers for the diagnosis of NAFLD and predicted drugs, decitabine and retinoic acid may have a potential role in the treatment of NAFLD.

Bioinformatics-Based Analysis and Verification of Chromatin Regulators and the Mechanism of Immune Infiltration Associated with Myocardial Infarction.

Recent studies have shown that dysfunction in chromatin regulators (CRs) may be an important mechanism of myocardial infarction (MI). They are thus expected to become a new target in the diagnosis and treatment of MI. However, the diagnostic value of CRs in MI and the mechanisms are not clear. CRs-related differentially expressed genes (DEGs) were screened between healthy controls and patients with MI via GSE48060, GSE60993, and GSE66360 datasets. DEGs were further analyzed for enrichment analysis. Hub genes were screened by least absolute shrinkage and selection operator (LASSO) regression and weighted gene co-expression network analysis (WGCNA). GSE61144 datasets were further used to validate hub genes. RT-qPCR examined peripheral blood mononuclear cells (PBMCs) to verify expressions of hub genes. In addition, a correlation between hub genes and immune cell infiltration was identified by CIBERSORT and single-sample gene set enrichment analysis (ssGSEA). Finally, we constructed a diagnostic nomogram and ceRNA network and found possible therapeutic medicines which were based on hub genes. Firstly, 16 CR-related DEGs were identified. Next, Dual-specificity phosphatase 1 (DUSP1), growth arrest and DNA damage-inducible 45 (GADD45A), and transcriptional regulator Jun dimerization protein 2 (JDP2) were selected as hub genes by LASSO and WGCNA. Receiver operating characteristic curves in the training and test data sets verified the reliability of hub genes. Results of RT-qPCR confirmed the upregulation of hub genes in MI. Subsequently, the immune infiltration analysis indicated that DUSP1, GADD45A, and JDP2 were correlated with plasmacytoid dendritic cells, natural killer cells, eosinophils, effector memory CD4 T cells, central memory CD4 T cells, activated dendritic cells, and activated CD8 T cells. Furthermore, a nomogram that included DUSP1, GADD45A, and JDP2 was created. The calibration curve, decision curve analysis, and the clinical impact curve indicated that the nomogram could predict the occurrence of MI with high efficacy. The results of the ceRNA network suggest that hub genes may be cross-regulated by various lncRNAs and miRNAs. In addition, 10 drugs, including 2H-1-benzopyran, Nifuroxazide, and Bepridil, were predicted to be potential therapeutic agents for MI. Our study identifies three promising genes associated with the progression of chromatin regulators (CRs)-related myocardial infarction (MI) and immune cell infiltration, including Dual-specificity phosphatase 1 (DUSP1), growth arrest and DNA damage-inducible 45 (GADD45A), and Jun dimerization protein 2 (JDP2), which might be worthy of further study.

SR9009 attenuates TGF-β1-induced renal fibrotic responses by inhibiting the NOX4/p38 signaling pathway in NRK-49F cells

The circadian clock protein reverse erythroblastosis virus (REV)-ERBα is implicated in the pathogenesis of various diseases, including cancer and myocardial infarction. Emerging evidence suggests that SR9009, an agonist of REV-ERBα, regulates multiple signaling molecules independent or dependent of REV-ERBα. However, the impact of SR9009 on renal fibrosis remains largely unevaluated. In this study, we investigated the effects of SR9009 on transforming growth factor (TGF)-β1-induced fibrotic responses and elucidated the mechanisms involved. Masson's trichome staining revealed that in the unilateral ureteral obstruction groups, there was a decrease in REV-ERBα expression, accompanied by increased levels of the profibrotic factor TGF-β1 and the fibrosis marker α-smooth muscle actin (α-SMA). REV-ERBα knockdown significantly increased α-SMA expression in NRK-49F cells. SR9009 significantly attenuated unilateral ureteral obstruction-induced fibrosis and TGF-β1-induced fibrotic responses in normal rat kidney fibroblasts (NRK-49F cells). Conversely, the REV-ERBα antagonist SR8278 did not affect TGF-β1-induced fibrotic responses. Mechanistic studies revealed that SR9009 significantly inhibited the phosphorylation of ERK and p38, concomitant with reduced α-SMA levels, suppressing TGF-β1-induced NADPH oxidase 4 (NOX4) mRNA expression in NRK-49F cells. Notably, SR9009 did not influence the expression of dual specificity phosphatase 4, which dephosphorylates MAPKs, including p38. Furthermore, REV-ERBα knockdown did not affect the ability of SR9009 to inhibit TGF-β1-induced fibrotic responses and NOX4 expression in NRK-49F cells. In conclusion, SR9009 exerts a protective role against renal fibrosis independent of REV-ERBα. Therefore, SR9009 is a promising therapeutic agent for the prevention and treatment of renal fibrosis associated with renal failure.

Exploring the mechanism of berberine treatment for atherosclerosis combined with non-alcoholic fatty liver disease based on bioinformatic and experimental study.

Atherosclerosis (AS) and Non-alcoholic fatty liver disease (NAFLD) are chronic metabolic disorders with high prevalence and significant health impacts. Both conditions share common pathophysiological pathways including abnormal lipid metabolism and inflammation. Berberine (BBR), an isoquinoline alkaloid, is known for its beneficial effects on various metabolic and cardiovascular disorders. This study investigates BBR's impact on AS and NAFLD through bioinformatics analysis and experimental models. This study utilized various bioinformatics methods, including transcriptome analysis, weighted gene co-expression network analysis (WGCNA), machine learning, and molecular docking, to identify key genes and pathways involved in AS and NAFLD. Subsequently an animal model of AS combined with NAFLD was established using ApoE-/- mice fed a high-fat diet. The efficacy and mechanism of action of BBR were verified using methods such as hematoxylin and eosin (HE) staining, Oil Red O staining, and real-time quantitative PCR (RTqPCR). Through transcriptome analysis, WGCNA, and machine learning, this study identified 48 key genes involved in both AS and NAFLD. Function analysis revealed that the implicated genes were significantly involved in pathways like cytokine-cytokine receptor interaction, chemokine signaling, and IL-17 signaling pathway, suggesting their role in inflammation and immune responses. Single cell validation identified six key genes: dual specificity phosphatase 6 (DUSP6), chemokine ligand 3 (CCL3), complement component 5a receptor 1 (C5AR1), formyl peptide receptor 1 (FPR1), myeloid nuclear differentiation antigen (MNDA), and proviral integration site of murine 2(PIM2). Finally, molecular docking and animal experiments showed that BBR significantly reduced lipid deposits and inflammatory markers in liver and aortic tissues. In conclusion, BBR can improve AS combined with NAFLD by regulating genes like MNDA, PIM2, DUSP6, CCL3, C5AR1, and FPR1, with the mechanism related to inflammation control. The findings suggest potential clinical benefits of BBR in reducing the progression of both AS and NAFLD, warranting further investigation.

Spatiotemporal Profiling Defines Persistence and Resistance Dynamics During Targeted Treatment of Melanoma.

Resistance of BRAF-mutant melanomas to targeted therapy arises from the ability of cells to enter a persister state, evade treatment with relative dormancy, and repopulate the tumor when reactivated. A better understanding of the temporal dynamics and specific pathways leading into and out of the persister state is needed to identify strategies to prevent treatment failure. Using spatial transcriptomics in patient-derived xenograft models, we captured clonal lineage evolution during treatment. The persister state showed increased oxidative phosphorylation, decreased proliferation, and increased invasive capacity, with central-to-peripheral gradients. Phylogenetic tracing identified intrinsic and acquired resistance mechanisms (e.g., dual specific phosphatases, reticulon-4, and CDK2) and suggested specific temporal windows of potential therapeutic susceptibility. Deep learning-enabled analysis of histopathological slides revealed morphological features correlating with specific cell states, demonstrating that juxtaposition of transcriptomics and histological data enabled identification of phenotypically distinct populations from using imaging data alone. In summary, this study defined state change and lineage selection during melanoma treatment with spatiotemporal resolution, elucidating how choice and timing of therapeutic agents will impact the ability to eradicate resistant clones.

Dual-specificity phosphatase 23 functions as a promising prognostic biomarker in non-small cell lung cancer.

The mechanical remodeling of tumor microenvironment is critical for non-small cell lung cancer (NSCLC) progression. Dual-specificity phosphatase 23 (DUSP23) has been previously identified as a mechano-responsive gene, but its role in NSCLC progression remains unknown. We aim to elucidate the clinical significance of DUSP23 in NSCLC progression. We analyzed the expression of DUSP23 in cancer using polyacrylamide hydrogels designed to mimic the stiffness of normal (soft; ~0.5kPa) and cancerous (stiff; ~40kPa) tissues. The prognostic significance of DUSP23 expression in patients was examined using public databases. Additionally, we conducted various cell-based assays and transcriptomic analyses in DUSP23-silenced NSCLC cell lines. A risk score prognosis model was constructed using univariate Cox regression and Kaplan-Meier analysis. Our findings show that DUSP23 is upregulated in stiff matrices and is highly associated with poor prognosis in patients with solid cancers such as NSCLC and breast cancer. Silencing of DUSP23 resulted in decreased cell proliferation and invasion. Transcriptomic profiling revealed that 182 genes were downregulated, and 230 genes upregulated following DUSP23-depletion. Notably, 182 downregulated genes were enriched in cancer-related pathways, including cell cycle progression and cytoskeleton organization. Through KEGG pathway analysis, we identified 11 cancer-related genes and developed a prognostic risk model. In this model, the high-risk group of NSCLC patients exhibited significantly shorter overall survival compared to low-risk group, based on public datasets. Our study demonstrates the clinical significance of DUSP23 as a prognostic marker in NSCLC and highlights its potential role of DUSP23 in promoting NSCLC progression.

Screening of potential biomarkers of osteoarthritis: a bioinformatics analysis.

Osteoarthritis (OA) is the most common joint disease worldwide, with an age-associated increasing in both incidence and prevalence. However, early diagnosis of OA is a challenge due to the lack of effective biomarkers. This study aimed to identify new biomarkers and mechanisms of OA. Microarray expression data of synovial tissues from osteoarthritic and healthy populations were downloaded from the Gene Expression Omnibus (GEO) database, and differentially expressed genes (DEGs) were identified using GEO2R. Functions and enrichment pathways of DEGs were explained by enrichment analysis and construction of protein-protein interaction (PPI) networks, and hub genes were identified. By performing Venn analysis on the DEGs obtained from the two datasets, 28 upregulated and 84 downregulated DEGs were gained. JUN, activating transcription factor 3 (ATF3), and Dual-specificity phosphatase 1 (DUSP1), which play important roles in OA, were screened using PPI network construction. The receiver operating characteristic (ROC) curve of JUN, ATF3, and DUSP1 revealed satisfactory diagnostic value for OA. hsa-mir-26b-5p interacts with JUN, ATF3, and DUSP1. The expression of JUN, ATF3, and DUSP1 was reduced in patients with OA and the three genes mentioned above could be used as potential markers for the diagnosis of OA. hsa-mir-26b-5p may play an important role in the pathogenesis of OA and may be a potential therapeutic target. Key Points • JUN, ATF3, and DUSP1 could be used as potential markers for the diagnosis of OA. • hsa-mir-26b-5p may play an important role in the pathogenesis of OA.

Role of Dual Specificity Phosphatase 1 (DUSP1) in influencing inflammatory pathways in macrophages modulated by Borrelia burgdorferi lipoproteins.

Borrelia burgdorferi (Bb), the spirochetal agent of Lyme disease, has a large array of lipoproteins that play a significant role in mediating host-pathogen interactions within ticks and vertebrates. Although there is substantial information on the effects of B. burgdorferi lipoproteins (BbLP) on immune modulatory pathways, the application of multi-omics methodologies to decode the transcriptional and proteomic patterns associated with host cell responses induced by lipoproteins in murine bone marrow-derived macrophages (BMDMs) has identified additional effectors and pathways. Single-cell RNA-Seq (scRNA-Seq) performed on BMDMs treated with various concentrations of borrelial lipoproteins revealed macrophage subsets within the BMDMs. Differential expression analysis showed that genes encoding various receptors, type I IFN-stimulated genes, signaling chemokines, and mitochondrial genes are altered in BMDMs in response to lipoproteins. Unbiased proteomics analysis of lysates of BMDMs treated with lipoproteins corroborated several of these findings. Notably, dual specificity phosphatase 1 (Dusp1) gene was upregulated during the early stages of BMDM exposure to BbLP. Pre-treatment with benzylidene-3-cyclohexylamino-1-indanone hydrochloride (BCI), an inhibitor of both DUSP1 and 6 prior to exposure to BbLP, demonstrated that DUSP1 negatively regulates NLRP3-mediated pro-inflammatory signaling and positively regulates the expression of interferon-stimulated genes and those encoding Ccl5, Il1b, and Cd274. Moreover, DUSP1, IkB kinase complex and MyD88 also modulate mitochondrial changes in BMDMs treated with borrelial lipoproteins. These findings advance the potential for exploiting DUSP1 as a therapeutic target to regulate host responses in reservoir hosts to limit survival of B. burgdorferi during its infectious cycle between ticks and mammalian hosts.

The KLF16/MYC feedback loop is a therapeutic target in bladder cancer

BackgroundBladder cancer (BLCA) is a common malignancy characterized by dysregulated transcription and a lack of effective therapeutic targets. In this study, we aimed to identify and evaluate novel targets with clinical potential essential for tumor growth in BLCA.MethodsCRISPR-Cas9 screening was used to identify transcription factors essential for bladder cancer cell viability. The biological functions of KLF16 in bladder cancer were investigated both in vitro and in vivo. The regulatory mechanism between KLF16 and MYC was elucidated through a series of analyses, including RNA sequencing, quantitative polymerase chain reaction (qPCR), RNA immunoprecipitation, Western blotting, Mass spectrometry, Dual-luciferase reporter assays, Cleavage Under Targets and Tagmentation (CUT&Tag) sequencing, OptoDroplets assays, and RNA stability assay. The clinical relevance of KLF16 and MYC in bladder cancer was evaluated through analyses of public databases and immunohistochemistry.ResultsKrüppel-like factor 16 (KLF16) was essential for BLCA cell viability. Elevated expression of KLF16 was observed in bladder cancer tissues, and higher expression levels of KLF16 were correlated with poor progression-free survival (PFS) and cancer-specific survival (CSS) probabilities in BLCA patients. Mechanistically, KLF16 mRNA competed with the mRNA of dual-specificity phosphatase 16 (DUSP16) for binding to the RNA-binding protein, WW domain binding protein 11 (WBP11), resulting in destabilization of the DUSP16 mRNA. This, in turn, led to activation of ERK1/2, which stabilized the MYC protein. Furthermore, KLF16 interacted with MYC to form nuclear condensates, thereby enhancing MYC’s transcriptional activity. Additionally, MYC transcriptionally upregulated KLF16, creating a positive feedback loop between KLF16 and MYC that amplified their oncogenic functions. Targeting this loop with bromodomain inhibitors, such as OTX015 and ABBV-744, suppressed the transcription of both KLF16 and MYC, resulting in reduced BLCA cell viability and tumor growth, as well as increased sensitivity to chemotherapy.ConclusionsOur study revealed the crucial role of the KLF16/MYC regulatory axis in modulating tumor growth and chemotherapy sensitivity in BLCA, suggesting that combining bromodomain inhibitors, such as OTX015 or ABBV-744, with DDP or gemcitabine could be a promising therapeutic intervention for BLCA patients.

Genome-wide characterization and comparative expression profiling of dual-specificity phosphatase genes in yellow catfish (Pelteobagrus fulvidraco) after infection with exogenous Aeromonas hydrophila.

Dual-specificity phosphatases (DUSPs) are crucial regulators in many mammals, managing dephosphorylation and inactivation of mitogen-activated protein kinases (MAPKs) and playing essential roles in immune responses. However, their presence and functions in teleosts, like the yellow catfish (Pelteobagrus fulvidraco), remain unexplored. In this study, eight pfDusp genes (pfDusp1-7 and pfDusp10) were identified in yellow catfish. We characterized their molecular features, conserved protein sequences, and chromosomal localization through genome-wide analyses, and we examined their expression patterns in immune responses. Our findings reveal two conserved motifs, Leu-Phe-Leu-Gly and Ala-Tyr-Leu-Met, within the DSPc domain of DUSP proteins. The genes were mapped across seven chromosomes without evidence of duplication. Comparative analysis showed high conservation of Dusp genes across vertebrates, with evolutionary analysis suggesting Dusp3 as a potential intermediate form. Dusp transcripts were significantly upregulated in the kidney post-A. hydrophila infection. These results suggest the involvement of Dusp genes in the immune response of yellow catfish to bacterial pathogens, providing insights into their evolutionary significance and potential applications in aquaculture and molecular breeding.

Expression levels of some genes in the MAPK pathway (DUSP1, DUSP2, DUSP4, DUSP6 and DUSP10) in eyelid tumor tissue

Abstract Objectives To control mitogen-activated protein kinases (MAPK) signaling pathways involved in the onset and progression of cancer, dual specificity phosphatases (DUSPs/MKP) are essential. This study seeks to detect the correlation between eyelid tumors and the genes DUSPs, known for their influence on MAPK signaling pathways. Additionally, we aim to juxtapose our findings with analyses from various bioinformatics databases. Methods Expression levels of relevant genes in cDNA samples were determined by quantitative PCR method. Open-access databases were used for mutation analysis of relevant genes, mRNA expression changes, and survival analyses, and the STRING database was used for protein-protein interactions. Results It was found that the expression of DUSP1 and DUSP2 showed a significant decrease in the tumor tissue, while a significant increase was detected in the DUSP4 and DUSP6 genes. Additionally, when we compared the study genes with the Cancer Genome Atlas program cancer cohorts, it was found that the DUSP1 and DUSP10 gene expression profiles were downregulated in uveal melanoma compared to other cancer cohorts. Conclusions Significant and obvious changes were observed in the DUSP genes we studied in eyelid tumors. However, the relationship between these genes and cancer must be studied more. Considering that these enzymes are effective in cell proliferation, differentiation, and apoptosis, it would be appropriate to plan comprehensive studies on their interactions with other proteins they interact with in the MAPK pathway.

Drug prioritization identifies panobinostat as a tailored treatment element for patients with metastatic hepatoblastoma

BackgroundPatients with metastatic hepatoblastoma are treated with severely toxic first-line chemotherapies in combination with surgery. Yet, inadequate response of lung metastases to neo-adjuvant chemotherapy still compromises patient outcomes making new treatment strategies, tailored to more efficient lung clearance, mandatory.MethodsWe harnessed a comprehensive patient-derived xenograft platform and a variety of in vitro and in vivo assays to establish the preclinical and biological rationale for a new drug for patients with metastatic hepatoblastoma.ResultsThe testing of a library of established drugs on patient-derived xenografts identified histone deacetylase inhibitors, most notably panobinostat, to be highly efficacious on hepatoblastoma cells, as compared to non-cancerous cells. Molecularly, the anti-tumor effect of panobinostat is mediated by posttranslational obstruction of the MYC oncoprotein as a result of dual specificity phosphatase 1 upregulation, thereby leading to growth inhibition and programmed cell death. Of clinical importance, upregulation of the MYC target gene nucleophosmin 1 is indicative of response to panobinostat and associated with metastatic disease in patients with hepatoblastoma. The combination of panobinostat with the current SIOPEL 4 induction protocol, consisting of cisplatin and doxorubicin, revealed high synergies already at low nanomolar levels. The simulation of a clinical trial, with this combination therapy, in patient-derived xenograft models, and ultimately heterotypic lung metastasis mimics clearly underscored the potency of this approach.ConclusionIntegrated studies define MYC inhibition by panobinostat as a novel treatment element to be introduced into the therapeutic strategy for patients with metastatic hepatoblastoma.

Inositol pyrophosphate catabolism by three families of phosphatases regulates plant growth and development.

Inositol pyrophosphates (PP-InsPs) are nutrient messengers whose cellular levels are precisely regulated. Diphosphoinositol pentakisphosphate kinases (PPIP5Ks) generate the active signaling molecule 1,5-InsP8. PPIP5Ks harbor phosphatase domains that hydrolyze PP-InsPs. Plant and Fungi Atypical Dual Specificity Phosphatases (PFA-DSPs) and NUDIX phosphatases (NUDTs) are also involved in PP-InsP degradation. Here, we analyze the relative contributions of the three different phosphatase families to plant PP-InsP catabolism. We report the biochemical characterization of inositol pyrophosphate phosphatases from Arabidopsis and Marchantia polymorpha. Overexpression of different PFA-DSP and NUDT enzymes affects PP-InsP levels and leads to stunted growth phenotypes in Arabidopsis. nudt17/18/21 knock-out mutants have altered PP-InsP pools and gene expression patterns, but no apparent growth defects. In contrast, Marchantia polymorpha Mppfa-dsp1ge, Mpnudt1ge and Mpvip1ge mutants display severe growth and developmental phenotypes and associated changes in cellular PP-InsP levels. Analysis of Mppfa-dsp1geand Mpvip1ge mutants supports a role for PP-InsPs in Marchantia phosphate signaling, and additional functions in nitrate homeostasis and cell wall biogenesis. Simultaneous elimination of two phosphatase activities enhanced the observed growth phenotypes. Taken together, PPIP5K, PFA-DSP and NUDT inositol pyrophosphate phosphatases regulate growth and development by collectively shaping plant PP-InsP pools.

Utility of patient-derived xenografts to evaluate drug sensitivity and select optimal treatments for individual non-small-cell lung cancer patients

BackgroundPatient-derived xenograft (PDX) is currently considered a preferred preclinical model to evaluate drug sensitivity, explore drug resistance mechanisms, and select individualized treatment regimens.MethodsHistopathological examination, immunohistochemistry and whole-exome sequencing confirmed similarity between our PDX tumors and primary tumors in terms of morphology and genetic characteristics. The drug reactivity of the PDX tumor was validated in vivo. The mechanisms of acquired resistance to Osimertinib PDX tumors were investigated by WES and WB.ResultsWe successfully established 13 NSCLC-PDXs derived from 62 patients, including eight adenocarcinomas, four squamous-cell carcinoma, and one large-cell neuroendocrine carcinoma. Histological subtype and clinical stage were significant factors affecting the successful PDXs establishment. The treatment responses to conventional chemotherapy in PDXs were entirely consistent with that of their corresponding patients. According to the genetic status of tumors, more appropriate targeted agents were selected in PDXs for their corresponding patients as alternative treatment options. In addition, a PDX model with acquired resistance to osimertinib was induced, and the overactivation of RAS mitogen-activated protein kinase (MAPK)-extracellular signal-regulated kinase (ERK) signaling pathway caused by the dual-specificity phosphatase 6 (DUSP6) M62I mutation was found to play a key role in the development of osimertinib resistance. Trametinib, a specific inhibitor of the MAPK-ERK pathway significantly slowed down the tumor growth in osimertinib-resistant PDX models, providing an alternative treatment in patients after osimertinib failure.

Miro1 expression alters global gene expression, ERK1/2 phosphorylation, oxidation, and cell cycle progression.

Subcellular mitochondrial positioning in cells is necessary for localized energy and signaling requirements. Mitochondria are strategically trafficked throughout the cytoplasm via the actin cytoskeleton, microtubule motor proteins, and adaptor proteins. Miro1, an outer mitochondrial membrane adaptor protein, is necessary for attachment of mitochondria to microtubule motor proteins for trafficking. Previous work showed when Miro1 is deleted (Miro1-/-) from mouse embryonic fibroblasts (MEFs), the mitochondria become sequestered to the perinuclear space, disrupting subcellular energy and reactive oxygen species gradients. Here, we show that Miro1-/- MEFs grow slower compared to Miro1+/+ and Miro1-/- MEFs stably re-expressing the Myc-Miro1 plasmid. Miro1-/- MEFs have a have a cell cycle defect with decreased percentage of cells in G1 and increased cells in the S phase of the cell cycle. We conducted the first ever RNA sequencing experiment dependent upon Miro1 expression and found differential expression in cell proliferation and migration genes upon deletion of Miro1, including the MAP Kinase signaling pathway. We find that ERK1/2 phosphorylation is elevated both spatially (cytoplasm and nucleus) and temporally following serum stimulation in Miro1-/- MEFs. We investigated the expression levels and oxidation of the Dual Specificity Phosphatases (DUSP1-6), ERK1/2 target phosphatases. We found no differences in DUSP1-6 expression and oxidation under asynchronous and synchronized cells. Lastly, we evaluated the oxidation status of ERK1/2 and found an increase in ERK1/2 oxidation in the Miro1-/- MEFs compared to Miro1+/+ and Myc-Miro1. These data highlight transcriptional control based off Miro1 expression and demonstrate the highly dynamic regulation of ERK1/2 upon deletion of Miro1 that may support the observed cell cycle and proliferation defects.

Phosphoglycerate mutase 1-mediated dephosphorylation and degradation of Dusp1 disrupt mitochondrial quality control and exacerbate endotoxemia-induced myocardial dysfunction.

Rationale: Endotoxemia, caused by lipopolysaccharides, triggers systemic inflammation and myocardial injury by disrupting mitochondrial homeostasis. This study examines the roles of dual specificity phosphatase 1 (Dusp1) and phosphoglycerate mutase family member 1 (Pgam1) in this process. Methods: This study utilized cardiomyocyte-specific Dusp1 knockout (Dusp1Cko ) and transgenic (Dusp1Tg ) mice, alongside Pgam1 knockout (Pgam1Cko ) mice, subjected to LPS-induced endotoxemia. Echocardiography was performed to assess cardiac function. Mitochondrial integrity was evaluated using molecular techniques, including qPCR and Seahorse assays. Additionally, molecular docking studies and Western blot analyses were conducted to explore the interaction between Pgam1 and Dusp1. Results: Using single-cell sequencing and human sample databases, Dusp1 emerged as a novel biomarker for endotoxemia-induced myocardial dysfunction. Experiments with cardiomyocyte-specific Dusp1 knockout (Dusp1Cko ) and Dusp1 transgenic (Dusp1Tg ) mice showed that Dusp1 deficiency worsens, while overexpression improves, heart function during LPS-induced myocardial injury. This effect is mediated by regulating inflammation and cardiomyocyte viability. Molecular analyses revealed that LPS exposure leads to Dusp1 dephosphorylation at Ser364, increasing its degradation. Stabilizing Dusp1 phosphorylation enhances mitochondrial function through mitochondrial quality control (MQC), including dynamics, mitophagy, and biogenesis. Functional studies identified Pgam1 as an upstream phosphatase interacting with Dusp1. Pgam1 ablation reduced LPS-induced cardiomyocyte dysfunction and mitochondrial disorder. Conclusions: Pgam1-mediated dephosphorylation of Dusp1 disrupts mitochondrial quality control, leading to myocardial dysfunction in endotoxemia. Targeting the Pgam1-Dusp1 axis represents a promising therapeutic strategy for improving cardiac outcomes in patients with endotoxemia.

Targeting DUSP26 to drive cardiac mitochondrial dynamics via FAK-ERK signaling in diabetic cardiomyopathy

Diabetic cardiomyopathy (DCM) is a severe cardiac complication of diabetes mellitus, characterized by structural and functional myocardial abnormalities. The molecular mechanisms underlying DCM, particularly the role of dual-specificity phosphatase 26 (DUSP26), remain insufficiently understood. Our study reveals that DUSP26 expression is markedly downregulated in the cardiomyocytes of diabetic db/db mice and under glucolipotoxic stress. Overexpression of DUSP26 in db/db mice significantly improved cardiac function, as demonstrated by enhanced left ventricular ejection fraction and fractional shortening, alongside reduced myocardial fibrosis and hypertrophy. Mitochondrial analysis indicated that DUSP26 overexpression led to increased ATP production, enhanced mitochondrial fusion, and improved structural integrity. In addition, lipid accumulation was reduced, reflecting enhanced metabolic function. We also discovered that DUSP26 is necessary for regulating the focal adhesion kinase (FAK)-extracellular signal-regulated kinase (ERK) pathway, with pharmacological activation of FAK partially offsetting the benefits of DUSP26 overexpression in rescue experiments. These findings underscore the pivotal role of DUSP26 as a potential therapeutic target, highlighting the importance of developing targeted molecular interventions to address diabetic cardiac complications.