A protein phosphatase 1 specific phosphatase targeting peptide (PhosTAP) to identify the PP1 phosphatome.

Phosphoprotein phosphatases (PPPs) are the key serine/threonine phosphatases that regulate all essential signaling cascades. In particular, Protein Phosphatase 1 (PP1) dephosphorylates ~80% of all ser/thr phosphorylation sites. Here, we developed a phosphatase targeting peptide (PhosTAP) that binds all PP1 isoforms and does so with a stronger affinity than any other known PP1 regulator. This PhosTAP can be used as a PP1 recruitment tool for Phosphorylation Targeting Chimera (PhosTAC)-type recruitment in in vitro and cellular experiments, as well as in phosphoproteomics experiments to identify PP1-specific substrates and phosphosites. The latter is especially important to further our understanding of cellular signaling, as the identification of substrates and especially phosphosites that are targeted by specific phosphatases lags behind that of their kinase counterparts. Using PhosTAP-based proteomics, we show that, counter to our current understanding, many PP1 regulators are also substrates, that the number of residues between regulator PP1-binding and phosphosites vary significantly, and that PP1 counteracts the activities of mitotic kinases. Finally, we also found that Haspin kinase is a direct substrate of PP1 and that its PP1-dependent dephosphorylation modulates its activity during anaphase. Together, we show that PP1-specific PhosTAPs are a powerful tool for +studying PP1 activity in vitro and in cells.

GOLPH3 inhibition overcomes cisplatin resistance by restoring the glutathione/reactive oxygen species balance in the A549 non­small cell lung cancer cell line.

Cisplatin resistance is common in non­small cell lung cancer (NSCLC); however, the molecular mechanisms remain unclear. The present study aimed to identify a new function of Golgi phosphoprotein 3 (GOLPH3) in NSCLC­associated cisplatin resistance. Using A549 human NSCLC cells and the cisplatin­resistant variant, stable cell lines with GOLPH3 knockdown or overexpression were established using lentiviral vectors. Through Cell Counting Kit­8 and EdU assays, it was revealed that knockdown of GOLPH3 significantly enhanced cisplatin sensitivity in NSCLC cells. Specifically, flow cytometric analysis showed that GOLPH3 knockdown promoted apoptosis and G2­phase cell cycle arrest in A549 cells. Mechanistically, intracellular reactive oxygen species (ROS) and glutathione (GSH) levels were measured using assay kits, and it was demonstrated that GOLPH3 knockdown decreased intracellular GSH levels, and further attenuated intracellular cisplatin efflux and GSH/ROS imbalance. In addition, tumor­sphere formation assays verified that GOLPH3 knockdown mitigated the stem cell­like phenotype of NSCLC cells. In conclusion, the present findings indicated the relevance of GOLPH3 in NSCLC­associated cisplatin resistance, and thus targeting GOLPH3 may be developed into a combination therapy to overcome cisplatin resistance.

Neutrophil-specific Shp1 loss results in lethal pulmonary hemorrhage in mouse models of acute lung injury.

The acute respiratory distress syndrome (ARDS) is associated with significant morbidity and mortality and neutrophils are critical to its pathogenesis. Neutrophil activation is closely regulated by inhibitory tyrosine phosphatases including Src homology region 2 domain containing phosphatase-1 (Shp1). Here, we report that loss of neutrophil Shp1 in mice produced hyperinflammation and lethal pulmonary hemorrhage in sterile inflammation and pathogen-induced models of acute lung injury (ALI) through a Syk kinase-dependent mechanism. We observed large intravascular neutrophil clusters, perivascular inflammation, and excessive neutrophil extracellular traps in neutrophil-specific Shp1 knockout mice suggesting an underlying mechanism for the observed pulmonary hemorrhage. Targeted immunomodulation through the administration of a Shp1 activator (SC43) reduced agonist-induced reactive oxygen species in vitro and ameliorated ALI-induced alveolar neutrophilia and NETs in vivo. We propose that the pharmacologic activation of Shp1 has the potential to fine-tune neutrophil hyperinflammation that is central to the pathogenesis of ARDS.

SPP1 induces idiopathic pulmonary fibrosis and NSCLC progression via the PI3K/Akt/mTOR pathway.

BACKGROUND: The prevalence of non-small cell lung cancer (NSCLC) is notably elevated in individuals diagnosed with idiopathic pulmonary fibrosis (IPF). Secreted phosphoprotein 1 (SPP1), known for its involvement in diverse physiological processes, including oncogenesis and organ fibrosis, has an ambiguous role at the intersection of IPF and NSCLC. Our study sought to elucidate the function of SPP1 within the pathogenesis of IPF and its subsequent impact on NSCLC progression. METHODS: Four GEO datasets was analyzed for common differential genes and TCGA database was used to analyze the prognosis. The immune infiltration was analyzed by TIMER database. SPP1 expression was examined in human lung tissues, the IPF fibroblasts and the BLM-induced mouse lung fibrosis model. Combined with SPP1 gene gain- and loss-of-function, qRT-PCR, Western blot, EdU and CCK-8 experiments were performed to evaluate the effects and mechanisms of SPP1 in IPF progression. Effect of SPP1 on NSCLC was detected by co-cultured IPF fibroblasts and NSCLC cells. RESULTS: Through bioinformatics analysis, we observed a significant overexpression of SPP1 in both IPF and NSCLC patient datasets, correlating with enhanced immune infiltration of cancer-associated fibroblasts in NSCLC. Elevated levels of SPP1 were detected in lung tissue samples from IPF patients and bleomycin-induced mouse models, with partial colocalization observed with α-smooth muscle actin. Knockdown of SPP1 inhibits TGF-ß1-induced differentiation of fibroblasts to myofibroblasts and the proliferation of IPF fibroblasts. Conversely, SPP1 overexpression promoted IPF fibroblast proliferation via PI3K/Akt/mTOR pathway. Furthermore, IPF fibroblasts promoted NSCLC cell proliferation and activated the PI3K/Akt/mTOR pathway; these effects were attenuated by SPP1 knockdown in IPF fibroblasts. CONCLUSIONS: Our findings suggest that SPP1 functions as a molecule promoting both fibrosis and tumorigenesis, positioning it as a prospective therapeutic target for managing the co-occurrence of IPF and NSCLC.

High-Throughput Transcriptomics Identifies Chemoresistance-Associated Gene Expression Signatures in Human Angiosarcoma.

Angiosarcomas, clinically aggressive cancers of endothelial origin, are a rare subtype of soft-tissue sarcomas characterized by resistance to chemotherapy and dismal prognosis. In this study, we aim to identify the transcriptomic biomarkers of chemoresistance in angiosarcoma. We examined 72 cases of Asian angiosarcomas, including 35 cases treated with palliative chemotherapy, integrating information from NanoString gene expression profiling, whole transcriptome profiling (RNA-seq), immunohistochemistry, cell line assays, and clinicopathological data. In the chemoresistant cohort (defined as stable disease or progression), we observed the significant overexpression of genes, including SPP1 (log2foldchange 3.49, adj. p = 0.0112), CXCL13, CD48, and CLEC5A, accompanied by the significant enrichment of myeloid compartment and cytokine and chemokine signaling pathways, as well as neutrophils and macrophages. RNA-seq data revealed higher SPP1 expression (p = 0.0008) in tumor tissues over adjacent normal compartments. Immunohistochemistry showed a significant moderate positive correlation between SPP1 protein and gene expression (r = 0.7016; p < 0.00110), while higher SPP1 protein expression correlated with lower chemotherapeutic sensitivity in patient-derived angiosarcoma cell lines MOLAS and ISOHAS. In addition, SPP1 mRNA overexpression positively correlated with epithelioid histology (p = 0.007), higher tumor grade (p = 0.0023), non-head and neck location (p = 0.0576), and poorer overall survival outcomes (HR 1.84, 95% CI 1.07-3.18, p = 0.0288). There was no association with tumor mutational burden, tumor inflammation signature, the presence of human herpesvirus-7, ultraviolet exposure signature, and metastatic state at diagnosis. In conclusion, SPP1 overexpression may be a biomarker of chemoresistance and poor prognosis in angiosarcoma. Further investigation is needed to uncover the precise roles and underlying mechanisms of SPP1.

LMTK2 switches on canonical TGF-ß1 signaling in human bronchial epithelia.

Transforming Growth Factor (TGF-ß1) is a critical pro-fibrotic mediator in chronic lung disease, and there are no specific strategies to mitigate its adverse effects. Activation of TGF-ß1 signaling is a multipart process involving ligands, transmembrane receptors, and transcription factors. In addition, an intricate network of adaptor proteins fine-tunes the signaling strength, duration, and activity. Namely, Smad7 recruits growth arrest and DNA damage (GADD34) protein that then interacts with the catalytic subunit of phosphoprotein phosphatase 1 (PP1c) to inactivate TGF-ß Receptor (TßR)-I and downregulate TGF-ß1 signaling. Little is known about how TGF-ß1 releases TßR-I from the GADD34-PP1c inhibition to activate its signaling. Transmembrane Lemur Tyrosine Kinase 2 (LMTK2) is a PP1c inhibitor, and our published data showed that TGF-ß1 recruits LMTK2 to the cell surface. Here, we tested the hypothesis that TGF-ß1 recruits LMTK2 to inhibit PP1c, allowing activation of TßR-I. First, LMTK2 interacted with the TGF-ß1 pathway in the human bronchial epithelium at multiple checkpoints. Second, TGF-ß1 inhibited PP1c by an LMTK2-dependent mechanism. Third, TGF-ß1 utilized LMTK2 to activate canonical Smad3-mediated signaling. We propose a model whereby the LMTK2-PP1c and Smad7-GADD34-PP1c complexes serve as on-and-off switches in the TGF-ß1 signaling in human bronchial epithelium.

Research progress of the relationship between phosphoprotein phosphatases (PPPs) and neurodevelopmental disorders.

Reversible protein phosphorylation is a ubiquitous phenomenon essential for eukaryotic cellular processes. Recent advancements in research about neurodevelopmental disorders have prompted investigations into the intricate relationship between protein phosphatases, particularly phosphoprotein phosphatases (PPPs), and neurodevelopment. Notably, variants in 10 coding genes spanning four PPP family members have been implicated in neurodevelopmental disorders. Here, we provide a comprehensive overview of the clinical phenotypes, genotypes, and pathogenic mechanisms observed in affected patients. Our analysis reveals challenges in subsequent statistical analyses due to inconsistent clinical phenotypic descriptions and a lack of large multicenter studies, hampering analysis about genotype-phenotype correlations. The scarcity of follow-up data poses a significant obstacle to prognostic counseling for nearly all rare diseases. Presently, symptomatic treatment strategies are employed for patients with variants, as definitive cures remain elusive. Future research may explore protein phosphatase regulators as potential therapeutic targets. Furthermore, it is imperative not to overlook other members of the protein phosphatase family or coding genes with undiscovered variants. Insights gleaned from the temporal and spatial distribution of proteins, along with observations from animal model phenotypes, may provide valuable directions for uncovering novel pathogenic genes.

Anti-vasodilator-stimulated phosphoprotein (VASP) antibodies are associated with neuropsychiatric disorders in systemic lupus erythematosus.

Background: Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by multi-organ involvement and the presence of autoantibodies, pathogenic factors that can serve as diagnostic biomarkers. The current research has been focusing on exploring specific autoantigens with clinical relevance for SLE subtypes. In line with this objective, this study investigated potential antigenic targets associated with specific phenotypes in SLE by leveraging an omics-based approach combined with immunoassay techniques. Methods: A transcriptomic analysis was conducted in a cohort of 70 SLE patients to identify genes significantly correlated to the relevant phenotype. Epitope mapping and sequence analysis techniques were used to predict autoantigens, and the corresponding antibodies were subsequently quantified by enzyme-linked immunosorbent assay (ELISA) and validated by Western blot. Results: Transcriptomic data analysis revealed a group of hub genes exhibiting a significant correlation with the neuropsychiatric phenotype and a positive relationship with platelets. Subsequent epitope prediction for the corresponding proteins highlighted vasodilator-stimulated phosphoprotein (VASP) as a potential autoantigen. Moreover, ELISA and immunoblotting confirmed that the anti-VASP antibody present in the serum was significantly elevated in SLE patients with neuropsychiatric involvement and positively associated with demyelination. Conclusion: VASP harbors autoantigenic epitopes associated with neuropsychiatric phenotype, especially the demyelination symptom in SLE, and its antibodies may serve as promising biomarkers in this disease.

Endothelial Dysfunction in Obesity and Therapeutic Targets.

Parallel to the increasing prevalence of obesity in the world, the mortality from cardiovascular disease has also increased. Low-grade chronic inflammation in obesity disrupts vascular homeostasis, and the dysregulation of adipocyte-derived endocrine and paracrine effects contributes to endothelial dysfunction. Besides the adipose tissue inflammation, decreased nitric oxide (NO)-bioavailability, insulin resistance (IR), and oxidized low-density lipoproteins (oxLDLs) are the main factors contributing to endothelial dysfunction in obesity and the development of cardiorenal metabolic syndrome. While normal healthy perivascular adipose tissue (PVAT) ensures the dilation of blood vessels, obesity-associated PVAT leads to a change in the profile of the released adipo-cytokines, resulting in a decreased vasorelaxing effect. Higher stiffness parameter ß, increased oxidative stress, upregulation of pro-inflammatory cytokines, and nicotinamide adenine dinucleotide phosphate (NADP) oxidase in PVAT turn the macrophages into pro-atherogenic phenotypes by oxLDL-induced adipocyte-derived exosome-macrophage crosstalk and contribute to the endothelial dysfunction. In clinical practice, carotid ultrasound, higher leptin levels correlate with irisin over-secretion by human visceral and subcutaneous adipose tissues, and remnant cholesterol (RC) levels predict atherosclerotic disease in obesity. As a novel therapeutic strategy for cardiovascular protection, liraglutide improves vascular dysfunction by modulating a cyclic adenosine monophosphate (cAMP)-independent protein kinase A (PKA)-AMP-activated protein kinase (AMPK) pathway in PVAT in obese individuals. Because the renin-angiotensin-aldosterone system (RAAS) activity, hyperinsulinemia, and the resultant IR play key roles in the progression of cardiovascular disease in obesity, RAAS-targeted therapies contribute to improving endothelial dysfunction. By contrast, arginase reciprocally inhibits NO formation and promotes oxidative stress. Thus, targeting arginase activity as a key mediator in endothelial dysfunction has therapeutic potential in obesity-related vascular comorbidities. Obesity-related endothelial dysfunction plays a pivotal role in the progression of type 2 diabetes (T2D). The peroxisome proliferator-activated receptor gamma (PPARγ) agonist, rosiglitazone (thiazolidinedione), is a popular drug for treating diabetes; however, it leads to increased cardiovascular risk. Selective sodium-glucose co-transporter-2 (SGLT-2) inhibitor empagliflozin (EMPA) significantly improves endothelial dysfunction and mortality occurring through redox-dependent mechanisms. Although endothelial dysfunction and oxidative stress are alleviated by either metformin or EMPA, currently used drugs to treat obesity-related diabetes neither possess the same anti-inflammatory potential nor simultaneously target endothelial cell dysfunction and obesity equally. While therapeutic interventions with glucagon-like peptide-1 (GLP-1) receptor agonist liraglutide or bariatric surgery reverse regenerative cell exhaustion, support vascular repair mechanisms, and improve cardiometabolic risk in individuals with T2D and obesity, the GLP-1 analog exendin-4 attenuates endothelial endoplasmic reticulum stress.

Intracellular Ebola virus nucleocapsid assembly revealed by in situ cryo-electron tomography.

Filoviruses, including the Ebola and Marburg viruses, cause hemorrhagic fevers with up to 90% lethality. The viral nucleocapsid is assembled by polymerization of the nucleoprotein (NP) along the viral genome, together with the viral proteins VP24 and VP35. We employed cryo-electron tomography of cells transfected with viral proteins and infected with model Ebola virus to illuminate assembly intermediates, as well as a 9 Å map of the complete intracellular assembly. This structure reveals a previously unresolved third and outer layer of NP complexed with VP35. The intrinsically disordered region, together with the C-terminal domain of this outer layer of NP, provides the constant width between intracellular nucleocapsid bundles and likely functions as a flexible tether to the viral matrix protein in the virion. A comparison of intracellular nucleocapsids with prior in-virion nucleocapsid structures reveals that the nucleocapsid further condenses vertically in the virion. The interfaces responsible for nucleocapsid assembly are highly conserved and offer targets for broadly effective antivirals.

Impact of baseline SARS-CoV-2 load in plasma and upper airways on the incidence of acute extrapulmonary complications of COVID-19: a multicentric, prospective, cohort study.

BACKGROUND: Extrapulmonary complications (EPCs) are common in patients hospitalized for COVID-19, but data on their clinical consequences and association with viral replication and systemic viral dissemination is lacking. METHODS: Patients hospitalized for COVID-19 and enrolled in the TICO (Therapeutics for Inpatients with COVID-19) platform trial at 114 international sites between August 2020 and November 2021 were included in a prospective cohort study. We categorized EPCs into 39 event types within 9 categories and estimated their frequency through day 28 and their association with clinical outcomes through day 90. We analyzed the association between baseline viral burden (plasma nucleocapsid antigen [N-Ag] and upper airway viral load [VL]) and EPCs, adjusting for other baseline factors. RESULTS: 2,625 trial participants were included in the study. The median age was 57 years (IQR 46-68), 57.7% were male, and 537 (20.5%) had at least one EPC. EPCs were associated with higher day-90 all-cause mortality (HR 9.6, 95% CI 7.3, 12.7) after adjustment for other risk factors. The risk of EPCs increased with increasing baseline plasma N-Ag (HR 1.21 per log10 ng/L increase, 95% CI 1.09, 1.34), and upper airway VL (HR 1.12 per log10 copies/mL increase, 95% CI 1.04, 1.19), after adjusting for comorbidities, disease severity, inflammatory markers, and other baseline factors. Trial treatment allocation had no effect on EPC risk. CONCLUSIONS: Systemic viral dissemination as evidenced by high plasma N-Ag and high respiratory viral burden are associated with development of EPCs in COVID-19, which in turn are associated with higher 90-day mortality.

A three-way interface of the Nipah virus phosphoprotein X-domain coordinates polymerase movement along the viral genome.

Nipah virus (NiV) is a highly pathogenic paramyxovirus causing frequently lethal encephalitis in humans. The NiV genome is encapsidated by the nucleocapsid (N) protein. RNA synthesis is mediated by the viral RNA-dependent RNA polymerase (RdRP), consisting of the polymerase (L) protein complexed with the homo-tetrameric phosphoprotein (P). The advance of the polymerase along its template requires iterative dissolution and reformation of transient interactions between P and N protomers in a highly regulated process that remains poorly understood. This study applied functional and biochemical NiV polymerase assays to the problem. We mapped three distinct protein interfaces on the C-terminal P-X domain (P-XD), which form a triangular prism and engage L, the C-terminal N tail, and the globular N core, respectively. Transcomplementation assays using NiV L and N-tail binding-deficient mutants revealed that only one XD of a P tetramer binds to L, whereas three must be available for N-binding for efficient polymerase activity. The dissolution of the N-tail complex with P-XD was coordinated by a transient interaction between N-core and the α-1/2 face of this XD but not unoccupied XDs of the P tetramer, creating a timer for coordinated polymerase advance. IMPORTANCE: Mononegaviruses comprise major human pathogens such as the Ebola virus, rabies virus, respiratory syncytial virus, measles virus, and Nipah virus (NiV). For replication and transcription, their polymerase complexes must negotiate a protein-encapsidated RNA genome, which requires the highly coordinated continuous formation and resolution of protein-protein interfaces as the polymerase advances along the template. The viral P protein assumes a central role in this process, but the molecular mechanism of ensuring polymerase mobility is poorly understood. Studying NiV polymerase complexes, we applied functional and biochemical assays to map three distinct interfaces in the NiV P XD and identified transient interactions between XD and the nucleocapsid core as instrumental in coordinating polymerase advance. These results define a conserved molecular principle regulating paramyxovirus polymerase dynamics and illuminate a promising druggable target for the structure-guided development of broad-spectrum polymerase inhibitors.

Silencing SPP1 in M2 macrophages inhibits the progression of castration-resistant prostate cancer via the MMP9/TGFß1 axis.

Background: M2 macrophages can promote the progression of castration-resistant prostate cancer (CRPC), but the specific mechanism is still unclear. Therefore, we are preliminarily exploring the molecular mechanism by which M2 macrophages regulate the progression of CRPC. Methods: The genes positively correlated with CRPC and with the most significant differences in the GEO32269 dataset were obtained. Database and immunofluorescence experiments were used to validate the localization of secreted phosphoprotein 1 (SPP1) in localized prostate cancer (PCa), hormone-sensitive prostate cancer (HSPC), and CRPC tumor tissues. The function of SPP1 in M2 macrophages was verified through cell scratch, Transwell, and an orthotopic PCa model. PCa database and Western blot were used to verify the relationship between SPP1 and matrix metallopeptidase 9 (MMP9), as well as the ability of MMP9 in M2 macrophages to promote epithelial-mesenchymal transition (EMT) in PCa cells. Results: The primary localization of SPP1 in prostate and CRPC tissues is in macrophages. Silencing SPP1 expression in M2 macrophages promotes their polarization towards the M1 phenotype and significantly inhibits the malignant progression of PCa in vitro and in vivo. SPP1 promotes the expression of MMP9 through the PI3K/AKT signaling pathway in M2 macrophages. Furthermore, MMP9 enhances the EMT and migratory capabilities of PC3 cells by activating the TGFß signaling pathway. Conclusions: We have found that the high expression of SPP1 in M2 macrophages promotes the progression of CRPC through cell-cell interactions. These findings can contribute to the development of novel therapeutic approaches for combating this deadly disease.

Nucleophosmin: A Nucleolar Phosphoprotein Orchestrating Cellular Stress Responses.

Nucleophosmin (NPM1) is a key nucleolar protein released from the nucleolus in response to stress stimuli. NPM1 functions as a stress regulator with nucleic acid and protein chaperone activities, rapidly shuttling between the nucleus and cytoplasm. NPM1 is ubiquitously expressed in tissues and can be found in the nucleolus, nucleoplasm, cytoplasm, and extracellular environment. It plays a central role in various biological processes such as ribosome biogenesis, cell cycle regulation, cell proliferation, DNA damage repair, and apoptosis. In addition, it is highly expressed in cancer cells and solid tumors, and its mutation is a major cause of acute myeloid leukemia (AML). This review focuses on NPM1's structural features, functional diversity, subcellular distribution, and role in stress modulation.

The HIV latency reversing agent HODHBt inhibits the phosphatases PTPN1 and PTPN2.

Nonreceptor tyrosine phosphatases (NTPs) play an important role in regulating protein phosphorylation and have been proposed as attractive therapeutic targets for cancer and metabolic diseases. We have previously identified that 3-Hydroxy-1,2,3-benzotriazin-4(3H)-one (HODHBt) enhanced STAT activation upon cytokine stimulation, leading to increased reactivation of latent HIV and effector functions of NK and CD8 T cells. Here, we demonstrate that HODHBt interacted with and inhibited the NTPs PTPN1 and PTPN2 through a mixed inhibition mechanism. We also confirm that PTPN1 and PTPN2 specifically controlled the phosphorylation of different STATs. The small molecule ABBV-CLS-484 (AC-484) is an active site inhibitor of PTPN1 and PTPN2 currently in clinical trials for advanced solid tumors. We compared AC-484 and HODHBt and found similar effects on STAT5 and immune activation, albeit with different mechanisms of action leading to varying effects on latency reversal. Our studies provide the first specific evidence to our knowledge that enhancing STAT phosphorylation via inhibition of PTPN1 and PTPN2 is an effective tool against HIV.

SPP1 promotes the polarization of M2 macrophages through the Jak2/Stat3 signaling pathway and accelerates the progression of idiopathic pulmonary fibrosis.

Idiopathic pulmonary fibrosis (IPF) is a fatal pulmonary disease that requires further investigation to understand its pathogenesis. The present study demonstrated that secreted phosphoprotein 1 (SPP1) was aberrantly highly expressed in the lung tissue of patients with IPF and was significantly positively associated with macrophage and T­cell activity. Cell localization studies revealed that SPP1 was primarily overexpressed in macrophages, rather than in T cells. Functionally, knocking down SPP1 expression in vitro inhibited the secretion of fibrosis­related factors and M2 polarization in macrophages. Furthermore, knocking down SPP1 expression inhibited the macrophage­induced epithelial­to­mesenchymal transition in both epithelial and fibroblastic cells. Treatment with SPP1 inhibitors in vivo enhanced lung function and ameliorated pulmonary fibrosis. Mechanistically, SPP1 appears to promote macrophage M2 polarization by regulating the JAK/STAT3 signaling pathway both in vitro and in vivo. In summary, the present study found that SPP1 promotes M2 polarization of macrophages through the JAK2/STAT3 signaling pathway, thereby accelerating the progression of IPF. Inhibition of SPP1 expression in vivo can effectively alleviate the development of IPF, indicating that SPP1 in macrophages may be a potential therapeutic target for IPF.

Osteopontin: A novel marker of pre-symptomatic sporadic Alzheimer's disease.

INTRODUCTION: We investigate the role of osteopontin (OPN) in participants with Pre-symptomatic Alzheimer's disease (AD), mild cognitive impairment (MCI), and in AD brains. METHODS: Cerebrospinal fluid (CSF) OPN, AD, and synaptic biomarker levels were measured in 109 cognitively unimpaired (CU), parental-history positive Pre-symptomatic Evaluation of Experimental or Novel Treatments for Alzheimer's Disease (PREVENT-AD) participants, and in 167 CU and 399 participants with MCI from the Alzheimer's Disease Neuroimaging Initiative (ADNI) cohort. OPN levels were examined as a function of amyloid beta (Aß) and tau positivity. Survival analyses investigated the link between OPN and rate of conversion to AD. RESULTS: In PREVENT-AD, CSF OPN was positively correlated with synaptic biomarkers. In PREVENT-AD and ADNI, OPN was elevated in CSF Aß42/40(+)/total tau(+) and CSF Aß42/40(+)/phosphorylated tau181(+) individuals. In ADNI, OPN was increased in Aß(+) positron emission tomography (PET) and tau(+) PET individuals, and associated with an accelerated rate of conversion to AD. OPN was elevated in autopsy-confirmed AD brains. DISCUSSION: Strong associations between CSF OPN and key markers of AD pathophysiology suggest a significant role for OPN in tau neurobiology, particularly in the early stages of the disease. HIGHLIGHTS: In the Pre-symptomatic Evaluation of Experimental or Novel Treatments for Alzheimer's Disease cohort, we discovered that cerebrospinal fluid (CSF) osteopontin (OPN) levels can indicate early synaptic dysfunction, tau deposition, and neuronal loss in cognitively unimpaired elderly with a parental history. CSF OPN is elevated in amyloid beta(+) positron emission tomography (PET) and tau(+) PET individuals. Elevated CSF OPN is associated with an accelerated rate of conversion to Alzheimer's disease (AD). Elevated CSF OPN is associated with an accelerated rate of cognitive decline on the Alzheimer's Disease Assessment Scale-Cognitive subscale 13, Montreal Cognitive Assessment, Mini-Mental State Examination, and Clinical Dementia Rating Scale Sum of Boxes. OPN mRNA and protein levels are significantly upregulated in the frontal cortex of autopsy-confirmed AD brains.

SPP1 promotes tumor progression in esophageal carcinoma by activating focal adhesion pathway.

Background: Recurrence and metastasis are the major obstacles affecting the therapeutic efficacy and clinical outcomes for patients with esophageal carcinoma (ESCA). Secreted phosphoprotein 1 (SPP1) is considered as a hub gene in ESCA and is negatively associated with disease-free survival (DFS) in ESCA. However, the exact roles and underlying mechanisms remain elusive. This study aims to examine the roles of SPP1 on ESCA, and elucidate the potential mechanisms. Methods: Bioinformatics were used to analyze the expression of SPP1 in ESCA tissues, and its relations with clinicopathological characteristics and clinical prognosis in patients with ESCA based on The Cancer Genome Atlas (TCGA) dataset. Loss-of-function was conducted to examine the roles of SPP1 on malignant behaviors of ESCA cells by cell counting kit-8 (CCK8), plate clone, wound healing, and transwell assays. Gene set enrichment analysis (GSEA) was conducted to screen the pathways associated with SPP1 in ESCA. Then, the enriched pathway and the underlying mechanism were elucidated by western blotting, cell adhesion, and cell spreading assays. Lastly, Y15 [a specific inhibitor of focal adhesion kinase (FAK)] was used to examine its potential to inhibit tumor growth in ESCA cells. Results: SPP1 was upregulated in ESCA tissues compared to the adjacent nontumorous tissues, which was closely associated with clinical stage, lymph node metastasis, histological subtype, and p53 mutation. A high expression of SPP1 indicated a poor clinical prognosis in patients with ESCA. The knockdown of SPP1 inhibited cell proliferative, migratory, and invasive capacities in ESCA cells. GSEA indicated that the focal adhesion pathway was closely related with SPP1 in ESCA. Further studies confirmed that the knockdown of SPP1 suppressed cell adhesion ability and reduced the expression of p-FAK and p-Erk in ESCA cells. In addition, Y15 inhibited FAK autophosphorylation and dramatically inhibited cell proliferation, migration, and invasion in ESCA cells. Conclusions: SPP1 promotes tumor progression in ESCA by activating FAK/Erk pathway, and FAK is a potential therapeutic target to overcome tumor recurrence and metastasis of ESCA.

One-step enrichment and stepwise elution of glycoproteins and phosphoproteins by hydrophilic Ti4+-immobilized dendrimer poly(glycidyl methacrylate) microparticles functionalized with polyethylenimine and phytic acid.

Glycosylation and phosphorylation rank as paramount post-translational modifications, and their analysis heavily relies on enrichment techniques. In this work, a facile approach was developed for the one-step simultaneous enrichment and stepwise elution of glycoproteins and phosphoproteins. The core of this approach was the application of the novel titanium (IV) ion immobilized poly(glycidyl methacrylate) microparticles functionalized with dendrimer polyethylenimine and phytic acid. The microparticles possessed dual enrichment capabilities due to their abundant titanium ions and hydroxyl groups on the surface. They demonstrate rapid adsorption equilibrium (within 30 min) and exceptional adsorption capacity for ß-casein (1107.7 mg/g) and horseradish peroxidase (438.6 mg/g), surpassing that of bovine serum albumin (91.7 mg/g). Furthermore, sodium dodecyl sulfate-polyacrylamide gel electrophoresis was conducted to validate the enrichment capability. Experimental results across various biological samples, including standard protein mixtures, non-fat milk, and human serum, demonstrated the remarkable ability of these microparticles to enrich low-abundance glycoproteins and phosphoproteins from biological samples.

Effect of toxins from different periodontitis-associated bacteria on human platelet function.

BACKGROUND: Periodontitis is caused by a dysbiosis of oral bacteria resulting in alveolar bone destruction and teeth loss. The role of platelets in pathogenesis of periodontitis is a subject of research. The release of toxins from periodontitis-associated bacteria may influence platelet function and contribute to the modulation of hemostatic or inflammatory responses. Therefore, we explored platelet function upon exposure to defined toxins: leukotoxin A from Aggregatibacter actinomycetemcomitans (LtxA), a synthetic version of the C14-Tri-LAN-Gly peptide from Fusobacterium nucleatum (C14), and lipopolysaccharides from Porphyromonas gingivalis (LPS). METHODS: Light transmission aggregometry was performed after the addition of toxins to platelet-rich plasma in different doses. Flow cytometry was used to identify inhibitory effects of toxins by measuring phosphorylation of the vaso-dilator-stimulated phosphoprotein or to identify activating effects by the detection of CD62P expression. The release of chemokines derived from washed platelets was determined by immunoassays. RESULTS: Collagen-induced threshold aggregation values were diminished upon incubation with LtxA and C14, accompanied with an increase of vaso-dilator-stimulated phosphoprotein (VASP) phosphorylation, indicating platelet inhibition. In contrast, LPS did not affect aggregation but slightly enhanced CD62P expression under co-stimulation with low-dose thrombin pointing to slight platelet activation. The three toxins did not relevantly influence the secretion of chemokines. CONCLUSIONS: Although weak, the investigated toxins differently influenced human platelet function. LtxA and C14 mediated inhibitory effects, whereas LPS contributed to a slight activation of platelets. Further analysis of specific cellular responses mediated by bacterial toxins may render novel targets and suggestions for the treatment of periodontitis.