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Hamostaseologie Jun 2024This review summarizes the rationale and current data on the use of thrombopoietin receptor agonists (TPO-RAs) for treating severe thrombocytopenia in infants, children,...
This review summarizes the rationale and current data on the use of thrombopoietin receptor agonists (TPO-RAs) for treating severe thrombocytopenia in infants, children, and adolescents. It focuses on substances that have been approved by the U.S. Food and Drug Administration (FDA) and European Medicines Agency (EMA) for pediatric patients. Romiplostim and eltrombopag are already established as second-line treatment for persistent or chronic immune thrombocytopenia (ITP). As in adults, TPO-RAs are currently also evaluated in severe aplastic anemia (SAA), chemotherapy-induced thrombocytopenia (CIT), myelodysplastic syndromes (MDS), and poor engraftment after hematopoietic stem cell transplantation in pediatric and adolescent patients. Moreover, studies on the implication of TPO-RA in treating rare inherited thrombocytopenias, such as Wiskott-Aldrich syndrome (WAS), congenital amegakaryocytic thrombocytopenia (CAMT), or -associated thrombocytopenia, deserve future attention. Current developments include testing of avatrombopag and lusutrombopag that are approved for the treatment of thrombocytopenia associated with chronic liver disease (CLD) in adult patients. In pediatric and adolescent medicine, we expect in the near future a broader use of TPO-RAs as first-line treatment in primary ITP, thereby considering immunomodulatory effects that increase the rate of sustained remission off-treatment, and a selective use in rare inherited thrombocytopenias based on current clinical trials.
PubMed: 38925157
DOI: 10.1055/a-2247-4209 -
Haematologica Jun 2024Hematological cancers are among the most common cancers in adults and children. Despite significant improvements in therapies, many patients still succumb to the...
Hematological cancers are among the most common cancers in adults and children. Despite significant improvements in therapies, many patients still succumb to the disease. Therefore, novel therapies are needed. The Wiskott-Aldrich syndrome protein (WASp) family regulates actin assembly in conjunction with the Arp2/3 complex, a ubiquitous nucleation factor. WASp is expressed exclusively in hematopoietic cells and exists in two allosteric conformations: autoinhibited or activated. Here, we describe the development of EG-011, a first-in-class small molecule activator of the WASp auto-inhibited form. EG-011 possesses in vitro and in vivo anti-tumor activity as a single agent in lymphoma, leukemia, and multiple myeloma, including models of secondary resistance to PI3K, BTK, and proteasome inhibitors. The in vitro activity was confirmed in a lymphoma xenograft. Actin polymerization and WASp binding was demonstrated using multiple techniques. Transcriptome analysis highlighted homology with drugs-inducing actin polymerization.
PubMed: 38899342
DOI: 10.3324/haematol.2022.282672 -
MBio Jun 2024The modulation of actin polymerization is a common theme among microbial pathogens. Even though microorganisms show a wide repertoire of strategies to subvert the...
The modulation of actin polymerization is a common theme among microbial pathogens. Even though microorganisms show a wide repertoire of strategies to subvert the activity of actin, most of them converge in the ones that activate nucleating factors, such as the Arp2/3 complex. spp. are intracellular pathogens capable of establishing chronic infections in their hosts. The ability to subvert the host cell response is dependent on the capacity of the bacterium to attach, invade, avoid degradation in the phagocytic compartment, replicate in an endoplasmic reticulum-derived compartment and egress. Even though a significant number of mechanisms deployed by in these different phases have been identified and characterized, none of them have been described to target actin as a cellular component. In this manuscript, we describe the identification of a novel virulence factor (NpeA) that promotes niche formation. NpeA harbors a short linear motif (SLiM) present within an amphipathic alpha helix that has been described to bind the GTPase-binding domain (GBD) of N-WASP and stabilizes the autoinhibited state. Our results show that NpeA is secreted in a Type IV secretion system-dependent manner and that deletion of the gene diminishes the intracellular replication capacity of the bacterium. and experiments demonstrate that NpeA binds N-WASP and that the short linear motif is required for the biological activity of the protein.IMPORTANCEThe modulation of actin-binding effectors that regulate the activity of this fundamental cellular protein is a common theme among bacterial pathogens. The neural Wiskott-Aldrich syndrome protein (N-WASP) is a protein that several pathogens target to hijack actin dynamics. The highly adapted intracellular bacterium has evolved a wide repertoire of virulence factors that modulate many activities of the host cell to establish successful intracellular replication niches, but, to date, no effector proteins have been implicated in the modulation of actin dynamics. We present here the identification of a virulence factor that harbors a short linear motif (SLiM) present within an amphipathic alpha helix that has been described to bind the GTPase-binding domain (GBD) of N-WASP stabilizing its autoinhibited state. We demonstrate that this protein is a Type IV secretion effector that targets N-WASP-promoting intracellular survival and niche formation.
PubMed: 38847540
DOI: 10.1128/mbio.00726-24 -
British Journal of Pharmacology May 2024Cytoplasmic fragile X mental retardation 1 (FMR1)-interacting protein 2 (CYFIP2), as a component of the Wiskott-Aldrich syndrome protein family verprolin-homologous...
The mutated cytoplasmic fragile X mental retardation 1 (FMR1)-interacting protein 2 (CYFIP2 S968F) regulates cocaine-induced reward behaviour and plasticity in the nucleus accumbens.
BACKGROUND AND PURPOSE
Cytoplasmic fragile X mental retardation 1 (FMR1)-interacting protein 2 (CYFIP2), as a component of the Wiskott-Aldrich syndrome protein family verprolin-homologous protein (WAVE) regulatory complex, is involved in actin polymerization, contributing to neuronal development and structural plasticity. Mutating serine-968 to phenylalanine (S968F) in CYFIP2 causes an altered cocaine response in mice. The neuronal mechanisms underlying this response remain unknown.
EXPERIMENTAL APPROACH
We performed cocaine reward-related behavioural tests and examined changes in synaptic protein phenotypes and neuronal morphology in the nucleus accumbens (NAc), using CYFIP2 S968F knock-in mice to investigate the role of CYFIP2 in regulating cocaine reward.
KEY RESULTS
CYFIP2 S968F mutation attenuated cocaine-induced behavioural sensitization and conditioned place preference. Cocaine-induced c-Fos was not observed in the NAc of CYFIP2 S968F knock-in mice. However, c-Fos induction was still evident in the medial prefrontal cortex (mPFC). CYFIP2 S968F mutation altered cocaine-associated CYFIP2 signalling, glutamatergic protein expression and synaptic density in the NAc following cocaine exposure. To further determine the role of CYFIP2 in NAc neuronal activity and the mPFC projecting to the NAc activity-mediating reward response, we used optogenetic tools to stimulate the NAc or mPFC-NAc pathway and observed that optogenetic activation of the NAc or mPFC-NAc pathway induced reward-related behaviours. This effect was not observed in the S968F mutation in CYFIP2.
CONCLUSION AND IMPLICATIONS
These results suggest that CYFIP2 plays a role in controlling cocaine-mediated neuronal function and structural plasticity in the NAc, and that CYFIP2 could serve as a target for regulating cocaine reward.
PubMed: 38751203
DOI: 10.1111/bph.16427 -
BioRxiv : the Preprint Server For... Apr 2024Actin remodeling is spatiotemporally regulated by surface topographical cues on the membrane for signaling across diverse biological processes. Yet, the mechanism...
Actin remodeling is spatiotemporally regulated by surface topographical cues on the membrane for signaling across diverse biological processes. Yet, the mechanism dynamic membrane curvature prompts quick actin cytoskeletal changes in signaling remain elusive. Leveraging the precision of nanolithography to control membrane curvature, we reconstructed catalytic reactions from the detection of nano-scale curvature by sensing molecules to the initiation of actin polymerization, which is challenging to study quantitatively in living cells. We show that this process occurs via topographical signal-triggered condensation and activation of the actin nucleation-promoting factor (NPF), Neuronal Wiskott-Aldrich Syndrome protein (N-WASP), which is orchestrated by curvature-sensing BAR-domain protein FBP17. Such N-WASP activation is fine-tuned by optimizing FBP17 to N-WASP stoichiometry over different curvature radii, allowing a curvature-guided macromolecular assembly pattern for polymerizing actin network locally. Our findings shed light on the intricate relationship between changes in curvature and actin remodeling via spatiotemporal regulation of NPF/BAR complex condensation.
PubMed: 38712166
DOI: 10.1101/2024.04.25.591054 -
Experimental Cell Research Jun 2024Filopodia are thin, actin-rich projection from the plasma membrane that promote cancer cell invasion and migration. Sex-determining region Y-related high-mobility...
Filopodia are thin, actin-rich projection from the plasma membrane that promote cancer cell invasion and migration. Sex-determining region Y-related high-mobility group-box 4 (SOX4) is a crucial transcription factor that plays a role in the development and metastasis of colorectal cancer (CRC). However, the involvement of SOX4 in cytoskeleton remodeling in CRC remains unknown. For the first time, we demonstrate that SOX4 is a potent regulator of filopodia formation in CRC cells. Overexpression of SOX4 protein enhances both migration and invasion ability of HCT116, and CACO2 cells, which is relevant to the metastasis. Furthermore, through phalloidin staining, cytoskeleton re-assembly was observed in SOX4-modified cell lines. Enhanced expression of SOX4 increased the number and length of filopodia on cell surface. In contrast, silencing SOX4 in SW620 cells with higher endogenous expression of SOX4, impeded the filopodia formation. Moreover, SOX4 was found to be positively regulating the expression of central regulators of actin cytoskeleton - N-Wiskott-Aldrich syndrome protein (N-WASP); WAVE2; Actin related proteins, ARP2 and ARP3. Inhibiting the N-WASP/ARP2/3 pathway diminishes the filopodia formation and the migration of CRC cells. These results indicate the crucial role of SOX4 in the regulation of filopodia formation mediated by N-WASP/ARP2/3 pathway in CRC cells.
Topics: Humans; Colorectal Neoplasms; SOXC Transcription Factors; Cell Movement; Actin-Related Protein 2-3 Complex; Wiskott-Aldrich Syndrome Protein, Neuronal; Cytoskeleton; Pseudopodia; Caco-2 Cells; Signal Transduction; Gene Expression Regulation, Neoplastic; Cell Line, Tumor; HCT116 Cells; Actin Cytoskeleton
PubMed: 38705228
DOI: 10.1016/j.yexcr.2024.114059 -
Cell Death & Disease Apr 2024Abnormal intraneuronal accumulation of soluble and insoluble α-synuclein (α-Syn) is one of the main pathological hallmarks of synucleinopathies, such as Parkinson's...
Abnormal intraneuronal accumulation of soluble and insoluble α-synuclein (α-Syn) is one of the main pathological hallmarks of synucleinopathies, such as Parkinson's disease (PD). It has been well documented that the reversible liquid-liquid phase separation of α-Syn can modulate synaptic vesicle condensates at the presynaptic terminals. However, α-Syn can also form liquid-like droplets that may convert into amyloid-enriched hydrogels or fibrillar polymorphs under stressful conditions. To advance our understanding on the mechanisms underlying α-Syn phase transition, we employed a series of unbiased proteomic analyses and found that actin and actin regulators are part of the α-Syn interactome. We focused on Neural Wiskott-Aldrich syndrome protein (N-WASP) because of its association with a rare early-onset familial form of PD. In cultured cells, we demonstrate that N-WASP undergoes phase separation and can be recruited to synapsin 1 liquid-like droplets, whereas it is excluded from α-Syn/synapsin 1 condensates. Consistently, we provide evidence that wsp-1/WASL loss of function alters the number and dynamics of α-Syn inclusions in the nematode Caenorhabditis elegans. Together, our findings indicate that N-WASP expression may create permissive conditions that promote α-Syn condensates and their potentially deleterious conversion into toxic species.
Topics: alpha-Synuclein; Animals; Humans; Caenorhabditis elegans; Wiskott-Aldrich Syndrome Protein, Neuronal; Actins; Parkinson Disease; Synapsins; Caenorhabditis elegans Proteins
PubMed: 38693139
DOI: 10.1038/s41419-024-06686-7 -
Molecular Therapy. Methods & Clinical... Jun 2024
PubMed: 38680553
DOI: 10.1016/j.omtm.2024.101247 -
Tuberkuloz Ve Toraks Mar 2024Inborn errors of immunity (IEI) increase morbidity and mortality risks, particularly from respiratory tract infections. Hence, vaccination becomes pivotal for IEI...
INTRODUCTION
Inborn errors of immunity (IEI) increase morbidity and mortality risks, particularly from respiratory tract infections. Hence, vaccination becomes pivotal for IEI patients. This study aims to examine the vaccination and respiratory tract infection rates in a diverse IEI patient cohort undergoing immunoglobulin replacement therapy (IGRT).
MATERIALS AND METHODS
We retrospectively evaluated IEI patients on IGRT at a tertiary care center. Data on vaccinations and respiratory infections were extracted from medical records.
RESULT
: The study included 33 patients (mean age= 37.7 ± 11.4 years; 17 male). The most common clinical phenotype in our cohort was primary antibody deficiencies (90.9%). Only two patients had a genetic diagnosis, both of whom were brothers diagnosed with Wiskott-Aldrich syndrome (WAS). Almost half (48.5%) of our patients had bronchiectasis and 81.8% were on prophylactic antibiotics. All patients with IEI included in the study were regularly receiving IGRT. The vaccination rate of patients against respiratory tract infections was 42.4%, 57.6%, and 78.8% for influenza, pneumococcus, and COVID-19, respectively. Only one patient (7.1%) who received the influenza vaccine developed an upper respiratory tract infection. However, viral panel analysis could not be performed for this patient as they did not present to the hospital. The COVID-19 vaccination rate was notably higher than that of other vaccines, likely due to increased awareness during the pandemic, aided by public advisories and media influence.
CONCLUSIONS
We observed higher vaccination rates for the COVID-19 vaccine compared to other vaccines (influenza and pneumococcal vaccines). Although we observed the potential impact of social and governmental influence in increasing vaccination rates, it is crucial to acknowledge that vaccination decisions in IEI patients must be individualized.
Topics: Humans; Male; Female; Respiratory Tract Infections; Retrospective Studies; Adult; Vaccination; Middle Aged; Primary Immunodeficiency Diseases; Influenza Vaccines; COVID-19; Pneumococcal Vaccines; COVID-19 Vaccines; Immunoglobulins, Intravenous; SARS-CoV-2
PubMed: 38676589
DOI: 10.5578/tt.202401813 -
Journal of Proteome Research Jun 2024The programmed death-ligand 1 (PD-L1) is a key mediator of immunosuppression in the tumor microenvironment. The expression of PD-L1 in cancer cells is useful for the...
The programmed death-ligand 1 (PD-L1) is a key mediator of immunosuppression in the tumor microenvironment. The expression of PD-L1 in cancer cells is useful for the clinical determination of an immune checkpoint blockade (ICB). However, the regulatory mechanism of the PD-L1 abundance remains incompletely understood. Here, we integrated the proteomics of 52 patients with solid tumors and examined immune cell infiltration to reveal PD-L1-related regulatory modules. Wiskott-Aldrich syndrome protein (WASP) was identified as a potential regulator of PD-L1 transcription. In two independent cohorts containing 164 cancer patients, WASP expression was significantly associated with PD-L1. High WASP expression contributed to immunosuppressive cell composition, including cells positive for immune checkpoints (PD1, CTLA4, TIGIT, and TIM3), FoxP3+ Treg cells, and CD163+ tumor-associated macrophages. Overexpression of WASP increased, whereas knockdown of WASP decreased the protein level of PD-L1 in cancer cells without alteration of PD-L1 protein stability. The WASP-mediated cell migration and invasion were markedly attenuated by the silence of PD-L1. Collectively, our data suggest that WASP is a potential regulator of PD-L1 and the WASP/PD-L1 axis is responsible for cell migration and an immunosuppressive microenvironment.
Topics: Humans; B7-H1 Antigen; Proteomics; Tumor Microenvironment; Wiskott-Aldrich Syndrome Protein; Neoplasms; Cell Movement; Gene Expression Regulation, Neoplastic; Cell Line, Tumor
PubMed: 38661673
DOI: 10.1021/acs.jproteome.4c00124