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BioRxiv : the Preprint Server For... Jul 2023The mechanosensitive PIEZO channel family has been linked to over 26 disorders and diseases. Although progress has been made in understanding these channels at the...
The mechanosensitive PIEZO channel family has been linked to over 26 disorders and diseases. Although progress has been made in understanding these channels at the structural and functional levels, the underlying mechanisms of PIEZO-associated diseases remain elusive. In this study, we engineered four PIEZO-based disease models using CRISPR/Cas9 gene editing. We performed an unbiased chemical mutagen-based genetic suppressor screen to identify putative suppressors of a conserved gain-of-function variant that in human causes distal arthrogryposis type 5 (DA5; p. R2718P). Electrophysiological analyses indicate that is a gain-of-function allele. Using genomic mapping and whole genome sequencing approaches, we identified a candidate suppressor allele in the gene This gene is an ortholog of human (NCK-associated protein 1), a subunit of the Wiskott-Aldrich syndrome protein (WASP)-verprolin homologous protein (WAVE/SCAR) complex, which regulates F-actin polymerization. Depletion of by RNAi, or with the suppressor allele , significantly restored the small brood size and low ovulation rate, as well as alleviated the crushed oocyte phenotype of the mutant. Auxin-inducible degradation of GEX-3 revealed that only somatic-specific degradation of GEX-3 restored the reduced brood size in the mutants. Additionally, actin organization and orientation were disrupted and distorted in the mutants. Mutation of partially alleviated these defects. The identification of as a suppressor of the pathogenic variant suggests that the cytoskeleton plays an important role in regulating PIEZO channel activity and provides insight into the molecular mechanisms of DA5 and other PIEZO-associated diseases.
PubMed: 37546771
DOI: 10.1101/2023.07.24.550416 -
Frontiers in Medicine 2023Type B insulin resistance (TBIR) is a rare, often fulminant form of insulin resistance caused by autoantibodies against the insulin receptor. If left untreated, its...
Type B insulin resistance (TBIR) is a rare, often fulminant form of insulin resistance caused by autoantibodies against the insulin receptor. If left untreated, its mortality is high. Various immunosuppressive regimens have shown efficacy, but treatment effects are variable and time-delayed, and drug-induced complications may arise. We report a patient with TBIR arising as a complication of Wiskott-Aldrich syndrome. Stable remission of TBIR was achieved through allogeneic peripheral blood stem cell transplantation (PBSCT) over a follow-up period of more than 1.5 years. We thus demonstrate that PBSCT can be considered a treatment option in TBIR where conventional immunosuppressive therapy is ineffective or contraindicated.
PubMed: 37706022
DOI: 10.3389/fmed.2023.1200037 -
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 -
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 -
The Kaohsiung Journal of Medical... Jan 2024Long noncoding RNA MYLK antisense RNA 1 (MYLK-AS1) is the crux in multiple diseases. Therefore, the purpose of this study was to investigate the possible mechanism of...
LncRNA MYLK antisense RNA 1 activates cell division cycle 42/Neutal Wiskott-Aldrich syndrome protein pathway via microRNA-101-5p to accelerate epithelial-to-mesenchymal transition of colon cancer cells.
Long noncoding RNA MYLK antisense RNA 1 (MYLK-AS1) is the crux in multiple diseases. Therefore, the purpose of this study was to investigate the possible mechanism of MYLK-AS1. A total of 62 colon cancer (CC) specimens and paired adjacent normal tissues were collected, and the expression of MYLK-AS1, microRNA (miR)-101-5p/cell division cycle 42 (CDC42) was detected. CC cell lines were transfected with MYLK-AS1, miR-101-5p, CDC42-related plasmids, and the biological functions and markers of epithelial-mesenchymal transition (EMT) were analyzed. The binding relationship between MYLK-AS1, miR-101-5p, and CDC42 was evaluated. In CC tissues and cell lines, MYLK-AS1 and CDC42 were highly expressed, and miR-101-5p was lowly expressed. Inhibition of MYLK-AS1 or upregulation of miR-101-5p can inhibit CC cell growth and EMT. miR-101-5p inhibited CDC42/N-wasp axis activation in CC cells by targeting CDC42. Knockdown of CDC42 or upregulation of miR-101-5p partially reversed the effects caused by upregulation of MYLK-AS1. MYLK-AS1, which is significantly upregulated in CC, may be a molecular sponge for miR-101-5p, and MYLK-AS1 promotes the activation of the CDC42/N-wasp axis in CC cells by targeting CDC42 through miR-101-5p, which in turn promotes tumor development. MYLK-AS1 may be a potential biomarker and target for CC therapy.
Topics: Humans; MicroRNAs; RNA, Long Noncoding; Wiskott-Aldrich Syndrome Protein; Epithelial-Mesenchymal Transition; Colonic Neoplasms; Cell Cycle; Cell Line, Tumor; Cell Proliferation; Gene Expression Regulation, Neoplastic; Cell Movement; Calcium-Binding Proteins; Myosin-Light-Chain Kinase
PubMed: 37950620
DOI: 10.1002/kjm2.12773 -
Frontiers in Genetics 2023Hereditary spastic paraplegia (HSP) is a progressive upper-motor neurodegenerative disease. Mutations in the gene are associated with autosomal dominant HSP, spastic...
Hereditary spastic paraplegia (HSP) is a progressive upper-motor neurodegenerative disease. Mutations in the gene are associated with autosomal dominant HSP, spastic paraplegia 8 (SPG8). However, due to the small number of reported cases, the exact mechanism remains unclear. We report a Chinese family with HSP. The proband was referred to our hospital due to restless leg syndrome and insomnia. The preliminary clinical diagnosis of the proband was spastic paraplegia. Whole-exome sequencing (WES) and RNA splicing analysis were conducted to evaluate the genetic cause of the disease in this family. A novel splice-altering variant (c.712-2A>G) in the gene was detected and further verified by RNA splicing analysis and Sanger sequencing. Real-time qPCR analysis showed that the expression of genes involved in the Wiskott-Aldrich syndrome protein and SCAR homolog (WASH) complex and endosomal and lysosomal systems was altered due to this variant. A novel heterozygous splice-altering variant (c.712-2A>G) in the gene was detected in a Chinese family with HSP. Our study provided data for genetic counseling to this family and offered evidence that this splicing variant in the gene is significant in causing HSP.
PubMed: 38028608
DOI: 10.3389/fgene.2023.1205052 -
BMC Medical Genomics Aug 2023Neurodevelopmental disorder with absent language and variable seizures (NEDALVS, # 618707) are characterized by delayed speech and motor development, ocular... (Review)
Review
BACKGROUND
Neurodevelopmental disorder with absent language and variable seizures (NEDALVS, # 618707) are characterized by delayed speech and motor development, ocular abnormalities, and seizures. NEDAVLS is an autosomal dominant disorder caused by de novo mutations in the wasp protein family member 1 (WASF1) gene.
CASE PRESENTATION
We identified a de novo nonsense variant c.1516 C > T (p.Arg506*) of WASF1 gene (NM_003931.3) in two pediatric female patients with delayed motor and language development.
CONCLUSION
This case demonstrates the effective role of WES in the diagnosis of NEDALVS. To the best of our knowledge, this variant has not been reported in the Chinese population. This contributes to our further understanding of the disease and to research related to the genetic and clinical heterogeneity, the treatment and prognosis of the disease.
Topics: Humans; Female; Child; East Asian People; Neurodevelopmental Disorders; Asian People; Seizures; Wiskott-Aldrich Syndrome Protein Family
PubMed: 37641121
DOI: 10.1186/s12920-023-01630-8 -
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 -
BioRxiv : the Preprint Server For... Feb 2024During cell movement, cortical actin balances mechanical and osmotic forces to maintain cell function while providing the scaffold for cell shape. Migrating CD4 T cells...
During cell movement, cortical actin balances mechanical and osmotic forces to maintain cell function while providing the scaffold for cell shape. Migrating CD4 T cells have a polarized structure with a leading edge containing dynamic branched and linear F-actin structures that bridge intracellular components to surface adhesion molecules. These actin structures are complemented with a microtubular network beaded with membrane bound organelles in the trailing uropod. Disruption of actin structures leads to dysregulated migration and changes in morphology of affected cells. In HIV-1 infection, CD4 T cells have dysregulated movement. However, the precise mechanisms by which HIV-1 affects CD4 T cell movement are unknown. Here, we show that HIV-1 infection of primary CD4 T cells causes at least four progressive morphological differences as a result of virally induced cortical cytoskeleton disruption, shown by ultrastructural and time lapse imaging. Infection with a ΔNef virus partially abrogated the dysfunctional phenotype in infected cells and partially restored a wild-type shape. The pathological morphologies after HIV-1 infection phenocopy leukocytes which contain genetic determinants of specific T cell Inborn Errors of Immunity (IEI) or Primary Immunodeficiencies (PID) that affect the actin cytoskeleton. To identify potential actin regulatory pathways that may be linked to the morphological deformities, uninfected CD4 T cell morphology was characterized following addition of small molecule chemical inhibitors. The ARP2/3 inhibitor CK-666 recapitulated three of the four abnormal morphologies we observed in HIV-1 infected cells. Restoring ARP2/3 function and cortical actin integrity in people living with HIV-1 infection is a new avenue of investigation to eradicate HIV-1 infected cells from the body.
PubMed: 38405733
DOI: 10.1101/2023.07.27.550856 -
Cells Feb 2024Platelet function at vascular injury sites is tightly regulated through the actin cytoskeleton. The Wiskott-Aldrich syndrome protein-family verprolin-homologous protein...
Platelet function at vascular injury sites is tightly regulated through the actin cytoskeleton. The Wiskott-Aldrich syndrome protein-family verprolin-homologous protein (WAVE)-regulatory complex (WRC) activates lamellipodia formation via ARP2/3, initiated by GTP-bound RAC1 interacting with the WRC subunit CYFIP1. The protein FAM49b (Family of Unknown Function 49b), also known as CYRI-B (CYFIP-Related RAC Interactor B), has been found to interact with activated RAC1, leading to the negative regulation of the WRC in mammalian cells. To investigate the role of FAM49b in platelet function, we studied platelet-specific -, -, and /-mice. Platelet counts and activation of mice were comparable to those of control mice. On fully fibrinogen-coated surfaces, -platelets spread faster with an increased mean projected cell area than control platelets, whereas /-platelets did not form lamellipodia, phenocopying the -platelets. However, -platelets often assumed a polarized shape and were more prone to migrate on fibrinogen-coated surfaces. On 2D structured micropatterns, however, -platelets displayed reduced spreading, whereas spreading of - and /-platelets was enhanced. In summary, FAM49b contributes to the regulation of morphology and migration of spread platelets, but to exert its inhibitory effect on actin polymerization, the functional WAVE complex must be present.
Topics: Animals; Mice; Actin Cytoskeleton; Adaptor Proteins, Signal Transducing; Blood Platelets; Carrier Proteins; Fibrinogen; Mammals; rac1 GTP-Binding Protein
PubMed: 38391912
DOI: 10.3390/cells13040299