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European Journal of Pharmacology Aug 2024Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multi-organ involvement and autoantibody production. Patients with SLE face a substantial...
Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by multi-organ involvement and autoantibody production. Patients with SLE face a substantial risk of developing lupus nephritis (LN), which imposes a substantial burden on both patients and their families. Protein phosphatase 2A (PP2A) is a widely distributed serine/threonine phosphatase that participates in regulating multiple signaling pathways. Inhibition of PP2A has been implicated in the treatment of various diseases. LB-100, a small molecule inhibitor of PP2A, has demonstrated anti-tumor therapeutic effects and high safety profile in preclinical experiments. However, the role of PP2A and its inhibitor has been insufficiently studied in LN. In this study, we assessed the potential effects of LB-100 in both MRL/lpr mice and R848-induced BALB/c mice. Our findings indicated that LB-100 administration led to reduced spleen enlargement, decreased deposition of immune complexes, ameliorated renal damage, and improved kidney function in both spontaneous and R848-induced lupus mouse models. Importantly, we observed the formation of tertiary lymphoid structures (TLSs) in the kidneys of two distinct lupus mouse models. The levels of signature genes of TLS were elevated in the kidneys of lupus mice, whereas LB-100 mitigated chemokine production and inhibited TLS formation. In addition, we confirmed that inhibition or knockdown of PP2A reduced the production of T cell-related chemokines by renal tubular epithelial cells (RTEC). In summary, our study highlighted the renal protective potential of the PP2A inhibitor LB-100 in two distinct lupus mouse models, suggesting its potential as a novel strategy for treating LN and other autoimmune diseases.
Topics: Animals; Protein Phosphatase 2; Lupus Nephritis; Mice; Tertiary Lymphoid Structures; Female; Mice, Inbred BALB C; Mice, Inbred MRL lpr; Kidney; Disease Models, Animal; Spleen; Enzyme Inhibitors; Piperazines
PubMed: 38839028
DOI: 10.1016/j.ejphar.2024.176703 -
Journal of Medical Case Reports Jun 2024Acute myeloid leukemia (AML) is the second most common type of leukemia in children. Although prognostic and diagnostic tests of AML patients have improved, there is...
BACKGROUND
Acute myeloid leukemia (AML) is the second most common type of leukemia in children. Although prognostic and diagnostic tests of AML patients have improved, there is still a great demand for new reliable clinical biomarkers for AML. Read-through fusion transcripts (RTFTs) are complex transcripts of adjacent genes whose molecular mechanisms are poorly understood. This is the first report of the presence of the PPP1R1B::STARD3 fusion transcript in an AML patient. Here, we investigated the presence of PPP1R1B::STARD3 RTFT in a case of AML using paired-end RNA sequencing (RNA-seq).
CASE PRESENTATION
A Persian 12-year-old male was admitted to Dr. Sheikh Hospital of Mashhad, Iran, in September 2019 with the following symptoms, including fever, convulsions, hemorrhage, and bone pain. The patient was diagnosed with AML (non-M3-FAB subtype) based on cell morphologies and immunophenotypical features. Chromosomal analysis using the G-banding technique revealed t (9;22) (q34;q13).
CONCLUSIONS
Single-cell RNA sequencing (scRNA-seq) analysis suggested that the PPP1R1B promoter may be responsible for the PPP1R1B::STARD3 expression. Alterations in the level of lipid metabolites implicate cancer development, and this fusion can play a crucial role in the cholesterol movement in cancer cells. PPP1R1B::STARD3 may be considered a candidate for targeted therapies of the cholesterol metabolic and the PI3K/AKT signaling pathways involved in cancer development and progression.
Topics: Humans; Male; Leukemia, Myeloid, Acute; Child; Protein Phosphatase 1; Oncogene Proteins, Fusion
PubMed: 38835078
DOI: 10.1186/s13256-024-04536-w -
ELife Jun 2024Styxl2, a poorly characterized pseudophosphatase, was identified as a transcriptional target of the Jak1-Stat1 pathway during myoblast differentiation in culture. Styxl2...
Styxl2, a poorly characterized pseudophosphatase, was identified as a transcriptional target of the Jak1-Stat1 pathway during myoblast differentiation in culture. Styxl2 is specifically expressed in vertebrate striated muscles. By gene knockdown in zebrafish or genetic knockout in mice, we found that Styxl2 plays an essential role in maintaining sarcomere integrity in developing muscles. To further reveal the functions of Styxl2 in adult muscles, we generated two inducible knockout mouse models: one with being deleted in mature myofibers to assess its role in sarcomere maintenance, and the other in adult muscle satellite cells (MuSCs) to assess its role in de novo sarcomere assembly. We find that Styxl2 is not required for sarcomere maintenance but functions in de novo sarcomere assembly during injury-induced muscle regeneration. Mechanistically, Styxl2 interacts with non-muscle myosin IIs, enhances their ubiquitination, and targets them for autophagy-dependent degradation. Without Styxl2, the degradation of non-muscle myosin IIs is delayed, which leads to defective sarcomere assembly and force generation. Thus, Styxl2 promotes de novo sarcomere assembly by interacting with non-muscle myosin IIs and facilitating their autophagic degradation.
Topics: Animals; Mice; Mice, Knockout; Proteolysis; Sarcomeres; Zebrafish; Phosphoprotein Phosphatases
PubMed: 38829202
DOI: 10.7554/eLife.87434 -
Chemico-biological Interactions Jul 2024The cyclin-dependent kinase inhibitor 3 (CDKN3) gene, is over expressed in renal cell carcinoma (RCC). However, the cell biology functions of RCC are not well...
The cyclin-dependent kinase inhibitor 3 (CDKN3) gene, is over expressed in renal cell carcinoma (RCC). However, the cell biology functions of RCC are not well understood. The present study aimed to verify the ability of CDKN3 to promote the proliferation and migration of RCC through in vitro experiments. Subsequently, the clinical prognostic effects were analyzed using The Cancer Genome Atlas (TCGA; https://www.cancer.gov/) and Gene Expression Omnibus (GEO; https://www.ncbi.nlm.nih.gov/geo/). The chelators, di-2-pyridylketone 4,4-dimethyl-3-thiosemicarbazone (Dp44mT), an analogue of the anti-tumor agent, were screened through bioinformatics analysis. The expression of CDKN3 is positively correlated with the IC of Dp44mT. In two RCC cell lines, 786-0 and Caki-1, we conducted small interfering RNA (siRNA) knockdown of CDKN3 and overexpression of CDKN3 by transfection plasmid. Subsequently, we administered Dp44mT to examine the resulting alterations in cell proliferation, migration, and apoptosis, thereby elucidating the role of CDKN3 and Dp44mT in these processes. The results of the experiment revealed a positive association between CDKN3 expression and the proliferation of RCC cell lines. Down-regulating CDKN3 significantly increased the apoptosis rate and inhibited cell migration in 786-0 and Caki-1 cells. Furthermore, bioinformatics analysis revealed a high expression of CDKN3 in RCC and a negative association between CDKN3 expression and survival. Gene set enrichment analysis (GSEA) revealed a significant association between high CDKN3 expression and the cell cycle pathway. Furthermore, we identified Dp44mT as a drug highly correlated with CDKN3 through the database. Subsequent addition of Dp44mT resulted in similar findings to those observed upon CDKN3 knockdown. Our findings have important implications for the diagnosis and treatment of CDKN3 in RCC. Additionally, Dp44mT is likely to be a promising candidate for future clinical applications.
Topics: Humans; Carcinoma, Renal Cell; Cell Movement; Cell Proliferation; Kidney Neoplasms; Cell Line, Tumor; Cyclin-Dependent Kinase Inhibitor Proteins; Thiosemicarbazones; RNA, Small Interfering; Antineoplastic Agents; Gene Expression Regulation, Neoplastic; Dual-Specificity Phosphatases
PubMed: 38825053
DOI: 10.1016/j.cbi.2024.111092 -
International Immunopharmacology Jul 2024Cathepsin B (CTSB) and inflammatory cytokines are critical in initiating and developing pancreatitis. Calcineurin, a central calcium (Ca)-responsive signaling molecule,...
Cathepsin B (CTSB) and inflammatory cytokines are critical in initiating and developing pancreatitis. Calcineurin, a central calcium (Ca)-responsive signaling molecule, mediates acinar cell death and inflammatory responses leading to pancreatitis. However, the detailed mechanisms for regulating CTSB activity and inflammatory cytokine production are unknown. Myricetin (MC) exhibits various biological activities, including anti-inflammatory effects. Here, we aimed to investigate MC effects on pancreatitis and the underlying mechanisms. Prophylactic and therapeutic MC treatment ameliorated the severity of cerulein-, L-arginine-, and PDL-induced acute pancreatitis (AP). The inhibition of CTSB activity by MC was mediated via decreased calcineurin activity and macrophage infiltration, not neutrophils infiltration, into the pancreas. Additionally, calcineurin activity inhibition by MC prevented the phosphorylation of Ca/CaM-dependent protein kinase kinase 2 (CaMKK2) during AP, resulting in the inhibition of CaMKIV phosphorylation and adenosine monophosphate-activated protein kinase (AMPK) dephosphorylation. Furthermore, MC reduced nuclear factor-κB activation by modulating the calcineurin-CaMKIV-IKKα/β-Iκ-Bα and calcineurin-AMPK-sirtuin1 axes, resulting in reduced production of tumor necrosis factor-α, interleukin (IL)-1β, and IL-6. Our results showed that MC alleviated AP severity by inhibiting acinar cell death and inflammatory responses, suggesting that MC as a calcineurin and CaMKK2 signaling modulator may be a potential treatment for AP.
Topics: Animals; Pancreatitis; Flavonoids; Cytokines; Cathepsin B; Mice; Male; Mice, Inbred C57BL; Calcineurin; Anti-Inflammatory Agents; Calcium-Calmodulin-Dependent Protein Kinase Kinase; Ceruletide; NF-kappa B; Pancreas; Signal Transduction; Arginine; Disease Models, Animal; AMP-Activated Protein Kinases
PubMed: 38823179
DOI: 10.1016/j.intimp.2024.112284 -
Scientific Reports May 2024This study investigated whether K-Patlak derived from a shortened scan time for dynamic F-NaF PET/CT in chronic kidney disease (CKD) patients undergoing hemodialysis can...
This study investigated whether K-Patlak derived from a shortened scan time for dynamic F-NaF PET/CT in chronic kidney disease (CKD) patients undergoing hemodialysis can provide predictive accuracy comparable to that obtained from a longer scan. Twenty-seven patients on chronic hemodialysis, involving a total of 42 scans between December 2021 and August 2023 were recruited. Dynamic F-NaF PET/CT scans, lasting 60-90 min, were immediately acquired post-injection, covering the mid-twelfth thoracic vertebra to the pelvis region. K-Patlak analysis was performed on bone time-activity curves at 15, 30, 45, 60, and 90 min in the lumbar spine (L1-L4) and both anterior iliac crests. Spearman's rank correlation (r) and interclass correlation coefficient were used to assess the correlation and agreement of K-Patlak between shortened and standard scan times. Bone-specific alkaline phosphatase (BsAP) and tartrate-resistant acid phosphatase isoform 5b (TRAP5b) were tested for their correlation with individual K-Patlak. Strong correlations and good agreement were observed between K-Patlak values from shortened 30-min scans and longer 60-90-min scans in both lumbar spine (r = 0.858, p < 0.001) and anterior iliac crest regions (r = 0.850, p < 0.001). The correlation between BsAP and K-Patlak in the anterior iliac crests was weak and statistically insignificant. This finding suggests that a proposed shortened dynamic F-NaF PET/CT scan is effective in assessing bone metabolic flux in CKD patients undergoing hemodialysis, offering a non-invasive alternative approach for bone turnover prediction.
Topics: Humans; Positron Emission Tomography Computed Tomography; Male; Female; Renal Dialysis; Middle Aged; Renal Insufficiency, Chronic; Aged; Sodium Fluoride; Fluorine Radioisotopes; Bone Remodeling; Lumbar Vertebrae; Adult; Alkaline Phosphatase; Tartrate-Resistant Acid Phosphatase; Ilium
PubMed: 38822011
DOI: 10.1038/s41598-024-63476-z -
Anticancer Research Jun 2024Epidermal growth factor receptor (EGFR) over-expression is commonly observed in advanced head and neck squamous cell carcinoma (HNSCC) and is correlated with poor...
BACKGROUND/AIM
Epidermal growth factor receptor (EGFR) over-expression is commonly observed in advanced head and neck squamous cell carcinoma (HNSCC) and is correlated with poor patient outcomes. However, the role of dual-specificity phosphatase 6 (DUSP6) in EGFR-associated HNSCC progression remains poorly understood. This study aimed to investigate the correlation between DUSP6 expression and EGFR signaling in malignant HNSCC tissues.
MATERIALS AND METHODS
Data mining and in vitro assays were employed to assess DUSP6 expression levels in HNSCC tissues compared to normal tissues. Additionally, the correlation between DUSP6 and EGFR expression was examined. Functional assays were conducted to investigate the modulation of DUSP6 expression by EGFR signaling and its involvement in EGF-induced cell migration and anoikis resistance.
RESULTS
Our analysis revealed a significant elevation in DUSP6 expression in HNSCC tissues compared to normal tissues and a strong correlation between DUSP6 and EGFR expression. EGFR signaling modulated DUSP6 expression in a dose- and time-dependent manner, primarily through the extracellular signal-regulated kinase (ERK) pathway. Knockdown experiments demonstrated the functional role of DUSP6 in EGF-induced cell migration and anoikis resistance.
CONCLUSION
The findings of this study elucidate the intricate signaling networks governing DUSP6 expression and its interplay with EGFR signaling in HNSCC. Moreover, the results provide insights into the potential role of DUSP6 as a therapeutic target and highlight the importance of personalized treatment strategies in HNSCC management.
Topics: Humans; Dual Specificity Phosphatase 6; ErbB Receptors; Squamous Cell Carcinoma of Head and Neck; Cell Movement; Head and Neck Neoplasms; Disease Progression; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Anoikis; Signal Transduction; Carcinoma, Squamous Cell
PubMed: 38821599
DOI: 10.21873/anticanres.17060 -
Cell Stress & Chaperones Jun 2024Heart failure (HF) refers to a group of clinical syndromes in which various heart diseases lead to the inability of cardiac output to meet the metabolic needs of the... (Review)
Review
Heart failure (HF) refers to a group of clinical syndromes in which various heart diseases lead to the inability of cardiac output to meet the metabolic needs of the body's tissues. Cardiac metabolism requires enormous amounts of energy; thus, impaired myocardial energy metabolism is considered a key factor in the occurrence and development of HF. Mitochondria serve as the primary energy source for cardiomyocytes, and their regular functionality underpins healthy cardiac function. The mitochondrial quality control system is a crucial mechanism for regulating the functionality of cardiomyocytes, and any abnormality in this system can potentially impact the morphology and structure of mitochondria, as well as the energy metabolism of cardiomyocytes. Phosphoglycerate mutase 5 (PGAM5), a multifunctional protein, plays a key role in the regulation of mitochondrial quality control through multiple pathways. Therefore, abnormal PGAM5 function is closely related to mitochondrial damage. This article reviews the mechanism of PGAM5's involvement in the regulation of the mitochondrial quality control system in the occurrence and development of HF, thereby providing a theoretical basis for future in-depth research.
Topics: Humans; Heart Failure; Animals; Mitochondria, Heart; Phosphoprotein Phosphatases; Mitochondrial Proteins; Myocytes, Cardiac; Mitochondria; Energy Metabolism
PubMed: 38821173
DOI: 10.1016/j.cstres.2024.05.004 -
Science Advances May 2024PR65 is the HEAT repeat scaffold subunit of the heterotrimeric protein phosphatase 2A (PP2A) and an archetypal tandem repeat protein. Its conformational mechanics plays...
PR65 is the HEAT repeat scaffold subunit of the heterotrimeric protein phosphatase 2A (PP2A) and an archetypal tandem repeat protein. Its conformational mechanics plays a crucial role in PP2A function by opening/closing substrate binding/catalysis interface. Using in silico saturation mutagenesis, we identified PR65 "hinge" residues whose substitutions could alter its conformational adaptability and thereby PP2A function, and selected six mutations that were verified to be expressed and soluble. Molecular simulations and nanoaperture optical tweezers revealed consistent results on the specific effects of the mutations on the structure and dynamics of PR65. Two mutants observed in simulations to stabilize extended/open conformations exhibited higher corner frequencies and lower translational scattering in experiments, indicating a shift toward extended conformations, whereas another displayed the opposite features, confirmed by both simulations and experiments. The study highlights the power of single-molecule nanoaperture-based tweezers integrated with in silico approaches for exploring the effect of mutations on protein structure and dynamics.
Topics: Optical Tweezers; Molecular Dynamics Simulation; Point Mutation; Protein Conformation; Protein Phosphatase 2; Humans
PubMed: 38820156
DOI: 10.1126/sciadv.adn2208 -
International Journal of Medical... 2024This study aims to elucidate the roles of Phosphoglycerate Mutase Family Member 5 (Pgam5) and Prohibitin 2 (Phb2) in the context of hyperglycemia-induced myocardial...
This study aims to elucidate the roles of Phosphoglycerate Mutase Family Member 5 (Pgam5) and Prohibitin 2 (Phb2) in the context of hyperglycemia-induced myocardial dysfunction, a critical aspect of diabetic cardiomyopathy. The research employed primary cardiomyocytes, which were then subjected to hyperglycemia treatment to mimic diabetic conditions. We used siRNA transfection to knock down Pgam5 and overexpressed Phb2 using adenovirus transfection to assess their individual and combined effects on cardiomyocyte health. Mitochondrial function was evaluated through measurements of mitochondrial membrane potential using the JC-1 probe, and levels of mitochondrial reactive oxygen species (ROS) were assessed. Additionally, the study involved qPCR analysis to quantify the transcriptional changes in genes related to mitochondrial fission and mitophagy. Our findings indicate that hyperglycemia significantly reduces cardiomyocyte viability and impairs mitochondrial function, as evidenced by decreased mitochondrial membrane potential and increased ROS levels. Pgam5 knockdown was observed to mitigate these adverse effects, preserving mitochondrial function and cardiomyocyte viability. On the molecular level, Pgam5 was found to regulate genes associated with mitochondrial fission (such as Drp1, Mff, and Fis1) and mitophagy (including Parkin, Bnip3, and Fundc1). Furthermore, overexpression of Phb2 countered the hyperglycemia-induced mitochondrial dysfunction and normalized the levels of key mitochondrial antioxidant enzymes. The combined data suggest a protective role for both Pgam5 knockdown and Phb2 overexpression against hyperglycemia-induced cellular and mitochondrial damage. The study elucidates the critical roles of Pgam5 and Phb2 in regulating mitochondrial dynamics in the setting of hyperglycemia-induced myocardial dysfunction. By modulating mitochondrial fission and mitophagy, Pgam5 and Phb2 emerge as key players in preserving mitochondrial integrity and cardiomyocyte health under diabetic conditions. These findings contribute significantly to our understanding of the molecular mechanisms underlying diabetic cardiomyopathy and suggest potential therapeutic targets for mitigating myocardial dysfunction in diabetes.
Topics: Prohibitins; Myocytes, Cardiac; Mitochondrial Dynamics; Hyperglycemia; Humans; Membrane Potential, Mitochondrial; Diabetic Cardiomyopathies; Reactive Oxygen Species; Animals; Mitophagy; Phosphoprotein Phosphatases; Repressor Proteins; Mitochondria, Heart; Mitochondrial Proteins; Rats
PubMed: 38818468
DOI: 10.7150/ijms.92872