Mutations In Kinase Research Articles

Outcomes and prognosis of haploidentical haematopoietic stem cell transplantation in children with FLT3-ITD mutated acute myeloid leukaemia.

The presence of internal tandem duplication mutations in the FMS-like tyrosine kinase 3 receptor (FLT3-ITD) is a poor prognostic predictor in paediatric patients with acute myeloid leukaemia (AML). We evaluated the treatment outcomes and prognostic factors of 45 paediatric patients with FLT3-ITD AML who achieved complete remission before haploidentical haematopoietic stem cell transplantation (haplo-HSCT) at our institution from 2012 to 2021. Among the 45 patients, the overall survival (OS), event‑free survival (EFS), and cumulative incidence of relapse (CIR) rates were 74.9% ± 6.6%, 64.1% ± 7.2%, and 31.4% ± 7.1%, respectively, with 48.8 months of median follow-up. Univariate and multivariate analyses associated positive minimal residual disease (MRD) at pre-HSCT and non-remission (NR) after introduce 1 with inferior long-term survival. The 100-day cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) was 35.6% ± 5.2%, and that of grade III-IV aGVHD was 15.6% ± 3.0% The overall 4-year cumulative incidence of chronic graft-versus-host disease after transplantation was 35.7% ± 9.8%, respectively. In conclusion, haplo-HSCT may be a feasible strategy for paediatric patients with FLT3-ITD AML, and pre-HSCT MRD status and NR after introduce 1 significantly affected the outcomes.

EGFR signaling and pharmacology in oncology revealed with innovative BRET-based biosensors

Mutations of receptor tyrosine kinases (RTKs) are associated with the development of many cancers by modifying receptor signaling and contributing to drug resistance in clinical settings. We present enhanced bystander bioluminescence resonance energy transfer-based biosensors providing new insights into RTK biology and pharmacology critical for the development of more effective RTK-targeting drugs. Distinct SH2-specific effector biosensors allow for real-time and spatiotemporal monitoring of signal transduction pathways engaged upon RTK activation. Using EGFR as a model, we demonstrate the capacity of these biosensors to differentiate unique signaling signatures, with EGF and Epiregulin ligands displaying differences in efficacy, potency, and responses within different cellular compartments. We further demonstrate that EGFR single point mutations found in Glioblastoma or non-small cell lung cancer, impact the constitutive activity of EGFR and response to tyrosine kinase inhibitor. The BRET-based biosensors are compatible with microscopy, and more importantly characterize the next generation of therapeutics directed against RTKs.

Tom20 gates PINK1 activity and mediates its tethering of the TOM and TIM23 translocases upon mitochondrial stress

Mutations in PTEN-induced putative kinase 1 (PINK1) cause autosomal recessive early-onset Parkinson's disease (PD). PINK1 is a Ser/Thr kinase that regulates mitochondrial quality control by triggering mitophagy mediated by the ubiquitin (Ub) ligase Parkin. Upon mitochondrial damage, PINK1 accumulates on the outer mitochondrial membrane forming a high-molecular-weight complex with the translocase of the outer membrane (TOM). PINK1 then phosphorylates Ub, which enables recruitment and activation of Parkin followed by autophagic clearance of the damaged mitochondrion. Thus, Parkin-dependent mitophagy hinges on the stable accumulation of PINK1 on the TOM complex. Yet, the mechanism linking mitochondrial stressors to PINK1 accumulation and whether the translocases of the inner membrane (TIMs) are also involved remain unclear. Herein, we demonstrate that mitochondrial stress induces the formation of a PINK1-TOM-TIM23 supercomplex in human cultured cell lines, dopamine neurons, and midbrain organoids. Moreover, we show that PINK1 is required to stably tether the TOM to TIM23 complexes in response to stress such that the supercomplex fails to accumulate in cells lacking PINK1. This tethering is dependent on an interaction between the PINK1 N-terminal-C-terminal extension module and the cytosolic domain of the Tom20 subunit of the TOM complex, the disruption of which, by either designer or PD-associated PINK1 mutations, inhibits downstream mitophagy. Together, the findings provide key insight into how PINK1 interfaces with the mitochondrial import machinery, with important implications for the mechanisms of mitochondrial quality control and PD pathogenesis.

Computational insights into dynamics and conformational stability of N-acetylmannosamine kinase mutations

The activity of UDP-GlcNAc 2-epimerase/ManNAc kinase (GNE) is essential for the biosynthesis of sialic acid, which is involved in cellular processes in health and diseases. GNE contains an N-terminal epimerase domain and a C-terminal kinase domain (N-acetylmannosamine kinase, MNK). Mutations of the GNE protein led to hypoactivity of the enzyme and cause sialurea or autosomal recessive inclusion body myopathy/Nonaka myopathy. Here, we used all-atom molecular dynamics (MD) simulations to comprehend the folding, dynamics and conformational stability of MNK variants, including the wild type (WT) and three mutants (H677R, V696M and H677R/V696M). The deleterious and destabilizing nature of MNK mutants were predicted using different prediction tools. Results predicted that mutations modulate the stability, flexibility and function of MNK. The effect of mutations on the conformational stability and dynamics of MNK was next studied through the free-energy landscape (FEL), hydrogen-bonds and secondary structure changes. The FEL results show that the mutations interfere with various conformational transitions in both WT and mutants, exposing the structural underpinnings of protein destabilization and unfolding brought on by mutation. We discover that, when compared to the other two mutations, V696M and H677R/V696M, H677R has the most harmful effects. These findings have a strong correlation with published experimental studies that demonstrate how these mutations disrupt MNK activity. Hence, this computational study describes the structural details to unravel the mutant effects at the atomistic resolution and has implications for understanding the GNE's physiological and pathological role. Communicated by Ramaswamy H. Sarma

Neuroprotective Effects of the Nutraceutical Dehydrozingerone and Its C2-Symmetric Dimer in a Drosophila Model of Parkinson's Disease.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons responsible for unintended or uncontrollable movements. Mutations in the leucine-rich repeat kinase 2 locus contribute to genetic forms of PD. The fruit fly Drosophila melanogaster carrying this mutation (LRRK2-Dm) is an in vivo model of PD that develops motor impairment and stands for an eligible non-mammalian paradigm to test novel therapeutic approaches. Dehydrozingerone (DHZ) is a natural phenolic compound isolated from ginger and presents anti-inflammatory, antioxidant and neuroprotective properties, making it a potential therapeutic target for PD. We administered DHZ and its C2-symmetric dimer (DHZ-DIM) at 0.5 and 1 mM for 14 and 21 days in the LRRK2-Dm, with the aim of assessing changes in rescuing motor behavior, brain dopaminergic neurons, mitochondria and synapses (T-bars). The shorter treatment with both molecules revealed efficacy at the higher dose, improving climbing behavior with a prevention of dopaminergic neuronal demise. After 21 days, a recovery of the motor disability, dopaminergic neuron loss, mitochondrial damage and T-bars failure was observed with the DHZ-DIM. Our data indicate that the DHZ-DIM exerts a more potent neuroprotective effect with respect to the monomer in LRRK2-Dm, prompting further investigation of these compounds in rodent models of PD.

Discovery of a Cushing's syndrome protein kinase A mutant that biases signaling through type I AKAPs.

Adrenal Cushing's syndrome is a disease of cortisol hypersecretion often caused by mutations in protein kinase A catalytic subunit (PKAc). Using a personalized medicine screening platform, we discovered a Cushing's driver mutation, PKAc-W196G, in ~20% of patient samples analyzed. Proximity proteomics and photokinetic imaging reveal that PKAcW196G is unexpectedly distinct from other described Cushing's variants, exhibiting retained association with type I regulatory subunits (RI) and their corresponding A kinase anchoring proteins (AKAPs). Molecular dynamics simulations predict that substitution of tryptophan-196 with glycine creates a 653-cubic angstrom cleft between the catalytic core of PKAcW196G and type II regulatory subunits (RII), but only a 395-cubic angstrom cleft with RI. Endocrine measurements show that overexpression of RIα or redistribution of PKAcW196G via AKAP recruitment counteracts stress hormone overproduction. We conclude that a W196G mutation in the kinase catalytic core skews R subunit selectivity and biases AKAP association to drive Cushing's syndrome.

Paclitaxel mediates the PI3K/AKT/mTOR pathway to reduce proliferation of FLT3‑ITD+ AML cells and promote apoptosis.

Acute myeloid leukemia (AML) with internal tandem duplication (ITD) mutations in the FLT3 tyrosine kinase tend to have a poor prognosis. FLT3-ITD can promote the progress of AML by activating the PI3K/AKT/mTOR pathway. Paclitaxel (PTX) is a natural anticancer drug that has been widely used in chemotherapy for multiple malignancies. The present study used the CCK-8 assay, flow cytometry, PCR and western blotting to explore the anti-leukemia effect and possible mechanisms of PTX on MV4-11 cells with the FLT3-ITD mutation and the underlying mechanism. As a result, it was found that PTX could inhibit proliferation of MV4-11 cells and promoted apoptosis by inhibiting the PI3K/AKT/mTOR pathway.

Mutant anaplastic lymphoma kinase inhibitor identification by integrated in silico approaches

ABSTRACT Non-small-cell lung cancer (NSCLC) is the primary form of lung cancer globally and remains a leading cause of mortality. Anaplastic lymphoma kinase (ALK) mutations, such as I1171N + L1198H, have been discovered to confer resistance to current ALK inhibitors, reducing their therapeutic effectiveness. Addressing drug resistance necessitates exploring selective inhibitors for innovative therapeutic approaches. In this study, a structure-based pharmacophore model, using ALK-approved inhibitors, was developed to screen an In-house database for potential mutant ALK inhibitors. Compounds with requisite pharmacophoric features were evaluated for binding potential against the I1171N + L1198H ALK mutant phenotype. Selected hits underwent assessment for chemical reactivity, and dynamics stability. The study identified five chemical scaffolds (NS1-5) with favorable binding modes and pharmacokinetic properties. The conformational ensembles featured the average RMSD values, ranging from 0.4 to 0.6 nm. RMSF analysis revealed consistent side chain fluctuations with reduced flexibility, while Rog analysis indicated convergence of most complexes. NS1 and NS5, in particular emerged as promising candidates, exhibiting remarkable performance than others, with binding free energies of −210.12 ± 9.94 and −163.68 ± 11.14 kcal/mol, respectively. These findings thus suggest further exploration and optimisation of NS1 and NS5 for mutant ALK inhibitors for the treatment of NSCLC.

Cumulative incidence and risk factors of brain metastases in metastatic non-small cell lung cancer without baseline brain metastasis: Pooled analysis of individualized patient data from IMpower130, IMpower131, and IMpower150.

The objective of this study was to explore the abilities of atezolizumab plus chemotherapy in preventing brain metastases (BMs) among metastatic non-small cell lung cancer (NSCLC) without initial BMs, as well as the risk factors of BMs. Individual patient data from three trials involving first-line atezolizumab for metastatic NSCLC (IMpower130, IMpower131, and IMpower150) were pooled. Among patients without baseline BMs and without epidermal growth factor receptor(EGFR) and/or anaplastic lymphoma kinase (ALK) mutations, those receiving atezolizumab+chemotherapy±bevacizumab were classified as the atezolizumabplus chemotherapy group and those receiving placebo+chemotherapy±bevacizumab were classified as the chemotherapy group. The cumulative incidences of BM (CI-BMs) between the two groups were compared. Other factors associated with the CI-BM were analyzed by Cox regression analyses. With a median follow-up of 17.6 months (range, 0.03-33.64 months), 74 (3.1%) of the 2380 enrolled patients developed BMs, including 50 (3.1%) and 24 (3.0%) in the atezolizumab plus chemotherapy group (n=1589) and the chemotherapy group (n=791), respectively. The CI-BMs at 6, 12, and 24months were 1.7%, 2.8%, and 3.3%, respectively. After taking competing risk events into account, there was no significant difference in the CI-BMs between the two groups (p=.888). Nevertheless, the use of bevacizumab and the histology of nonsquamous NSCLC were found to be independently associated with the risk of BMs. In patients with metastatic EGFR/ALK wild-type NSCLC without baseline BMs, adding atezolizumab in the first-line treatment might not reduce the CI-BM. However, the administration of bevacizumab may reduce the risk of BMs.

MOB-mediated regulation of septation initiation network (SIN) signaling is required for echinocandin-induced hyperseptation in Aspergillus fumigatus.

Aspergillus fumigatus is a major invasive mold pathogen and the most frequent etiologic agent of invasive aspergillosis. The currently available treatments for invasive aspergillosis are limited in both number and efficacy. Our recent work has uncovered that the β-glucan synthase inhibitors, the echinocandins, are fungicidal against strains of A. fumigatus with defects in septation initiation network (SIN) kinase activity. These drugs are known to be fungistatic against strains with normal septation. Surprisingly, SIN kinase mutant strains also failed to invade lung tissue and were significantly less virulent in immunosuppressed mouse models. Inhibiting septation in filamentous fungi is therefore an exciting therapeutic prospect to both reduce virulence and improve current antifungal therapy. However, the SIN remains understudied in pathogenic fungi. To address this knowledge gap, we characterized the putative regulatory components of the A. fumigatus SIN. These included the GTPase, SpgA, it's two-component GTPase-activating protein, ByrA/BubA, and the kinase activators, SepM and MobA. Deletion of spgA, byrA, or bubA resulted in no overt septation or echinocandin susceptibility phenotypes. In contrast, our data show that deletion of sepM or mobA largely phenocopies disruption of their SIN kinase binding partners, sepL and sidB, respectively. Reduced septum formation, echinocandin hypersusceptibility, and reduced virulence were generated by loss of either gene. These findings provide strong supporting evidence that septa are essential not only for withstanding the cell wall disrupting effects of echinocandins but are also critical for the establishment of invasive disease. Therefore, pharmacological SIN inhibition may be an exciting strategy for future antifungal drug development.IMPORTANCESepta are important structural determinants of echinocandin susceptibility and tissue invasive growth for the ubiquitous fungal pathogen Aspergillus fumigatus. Components of the septation machinery therefore represent promising novel antifungal targets to improve echinocandin activity and reduce virulence. However, little is known about septation regulation in A. fumigatus. Here, we characterize the predicted regulatory components of the A. fumigatus septation initiation network. We show that the kinase activators SepM and MobA are vital for proper septation and echinocandin resistance, with MobA playing an essential role. Null mutants of mobA displayed significantly reduced virulence in a mouse model, underscoring the importance of this pathway for A. fumigatus pathogenesis.

Potts Hamiltonian Models and Molecular Dynamics Free Energy Simulations for Predicting the Impact of Mutations on Protein Kinase Stability.

Single-point mutations in kinase proteins can affect their stability and fitness, and computational analysis of these effects can provide insights into the relationships among protein sequence, structure, and function for this enzyme family. To assess the impact of mutations on protein stability, we used a sequence-based Potts Hamiltonian model trained on a kinase family multiple-sequence alignment (MSA) to calculate the statistical energy (fitness) effects of mutations and compared these against relative folding free energies (ΔΔGs) calculated from all-atom molecular dynamics free energy perturbation (FEP) simulations in explicit solvent. The fitness effects of mutations in the Potts model (ΔEs) showed good agreement with experimental thermostability data (Pearson r = 0.68), similar to the correlation we observed with ΔΔGs predicted from structure-based relative FEP simulations. Recognizing the possible advantages of using Potts models to rapidly estimate protein stability effects of kinase mutations seen in cancer genomics data, we used the Potts statistical energy model to estimate the stability effects of 65 conservative and nonconservative mutations across three distinct kinases (Wee1, Abl1, and Cdc7) with somatic mutations reported in the Genomic Data Commons (GDC) database. The ΔEs of these mutations calculated from the Potts model are consistent with the corresponding ΔΔGs from FEP simulations (Pearson ratio of 0.72). The agreement between these methods suggests that the Potts model may be used as a sequence-based tool for high-throughput screening of mutational effects as part of a computational pipeline for predicting the stability effects of mutations. We also demonstrate how the scalability of the fitness-based Potts model calculations permits analyses that are not easily accessed using FEP simulations. To this end, we employed site-saturation mutagenesis in the Potts model in order to investigate the relative stability effects of mutations seen in different cancer evolutionary scenarios. We used this approach to analyze the effects of drug pressure in Abl kinase by contrasting the relative fitness penalties of somatic mutations seen in miscellaneous cancer types with those calculated for mutations associated with cancer drug resistance. We observed that, in contrast to somatic mutations of Abl seen in various tumors that appear to have evolved neutrally, cancer mutations that evolved under drug pressure in Abl-targeted therapies tend to preserve enzyme stability.

The molecular interaction pattern of lenvatinib enables inhibition of wild-type or kinase-mutated FGFR2-driven cholangiocarcinoma

Fibroblast growth factor receptor (FGFR)−2 can be inhibited by FGFR-selective or non-selective tyrosine kinase inhibitors (TKIs). Selective TKIs are approved for cholangiocarcinoma (CCA) with FGFR2 fusions; however, their application is limited by a characteristic pattern of adverse events or evocation of kinase domain mutations. A comprehensive characterization of a patient cohort treated with the non-selective TKI lenvatinib reveals promising efficacy in FGFR2-driven CCA. In a bed-to-bench approach, we investigate FGFR2 fusion proteins bearing critical tumor-relevant point mutations. These mutations confer growth advantage of tumor cells and increased resistance to selective TKIs but remain intriguingly sensitive to lenvatinib. In line with clinical observations, in-silico analyses reveal a more favorable interaction pattern of lenvatinib with FGFR2, including an increased flexibility and ligand efficacy, compared to FGFR-selective TKIs. Finally, the treatment of a patient with progressive disease and a newly developed kinase mutation during therapy with a selective inhibitor results in a striking response to lenvatinib. Our in vitro, in silico, and clinical data suggest that lenvatinib is a promising treatment option for FGFR2-driven CCA, especially when insurmountable adverse reactions of selective TKIs or acquired kinase mutations occur.

N-Acetylcysteine Alters Disease Progression and Increases Janus Kinase Mutation Frequency in a Mouse Model of Precursor B-Cell Acute Lymphoblastic Leukemia.

B-cell acute lymphoblastic leukemia (B-ALL) is the most prevalent type of cancer in young children and is associated with high levels of reactive oxygen species (ROS). The antioxidant N-acetylcysteine (NAC) was tested for its ability to alter disease progression in a mouse model of B-ALL. Mb1-CreΔPB mice have deletions in genes encoding PU.1 and Spi-B in B cells and develop B-ALL at 100% incidence. Treatment of Mb1-CreΔPB mice with NAC in drinking water significantly reduced the frequency of CD19+ pre-B-ALL cells infiltrating the thymus at 11 weeks of age. However, treatment with NAC did not reduce leukemia progression or increase survival by a median 16 weeks of age. NAC significantly altered gene expression in leukemias in treated mice. Mice treated with NAC had increased frequencies of activating mutations in genes encoding Janus kinases 1 and 3. In particular, frequencies of Jak3 R653H mutations were increased in mice treated with NAC compared with control drinking water. NAC opposed oxidization of PTEN protein ROS in cultured leukemia cells. These results show that NAC alters leukemia progression in this mouse model, ultimately selecting for leukemias with high Jak3 R653H mutation frequencies. SIGNIFICANCE STATEMENT: In a mouse model of precursor B-cell acute lymphoblastic leukemia associated with high levels of reactive oxygen species, treatment with N-acetylcysteine did not delay disease progression but instead selected for leukemic clones with activating R653H mutations in Janus kinase 3.

Implications of two-component systems EnvZ/OmpR and BaeS/BaeR in in vitro temocillin resistance in Escherichia coli.

BaeS/BaeR is a two-component system of Escherichia coli that controls the expression of porins and efflux pumps. Its role in beta-lactam resistance is limited. To study the role of baeS/baeR two-component system in temocillin resistance in E. coli. E. coli strain BW25113 and single-gene deletion mutants related to two-component systems were collected from the KEIO collection. Double-gen deletion mutants were generated. Temocillin-resistant mutant frequencies were determined at 32 mg/L. E. coli BW25113 mutants were selected by selective pressure from serial passages. Biological costs were analysed by growth curves. Genomes of the generated mutants were sequenced. The expression level of the mdtA, mdtB, mdtC, acrD and tolC in the ΔbaeS mutant was determined by RT-PCR (with/without temocillin exposure). The frequency of temocillin mutants ranged from 2.12 × 10-8 to 4.51 × 10-8 in single-porin mutants. No mutants were recovered from E. coli BW25113 (>10-9). Selection of temocillin-resistant variants by serial passage yielded mutants up to 128 mg/L. Mutations were found in the baeS gene. Temocillin MICs ranged from 4 to 32 mg/L (highest MICs for ΔbaeS and ΔompR). The efflux pumps mdtA, mdtB, mdtC and acrD pumps were overexpressed 3-10-fold in the presence of temocillin in ΔbaeS compared to control. Mutations in the sensor histidine kinase, baeS, may be involved in temocillin resistance through the expression of the efflux pumps mdtABC and acrD. In addition, the low mutation rate may be a good predictor of temocillin activity.

DGK5β-derived phosphatidic acid regulates ROS production in plant immunity by stabilizing NADPH oxidase

In plant immunity, phosphatidic acid (PA) regulates reactive oxygen species (ROS) by binding to respiratory burst oxidase homolog D (RBOHD), an NADPH oxidase responsible for ROS production. Here, we analyze the influence of PA binding on RBOHD activity and the mechanism of RBOHD-bound PA generation. PA binding enhances RBOHD protein stability by inhibiting vacuolar degradation, thereby increasing chitin-induced ROS production. Mutations in diacylglycerol kinase 5 (DGK5), which phosphorylates diacylglycerol to produce PA, impair chitin-induced PA and ROS production. The DGK5 transcript DGK5β (but not DGK5α) complements reduced PA and ROS production in dgk5-1 mutants, as well as resistance to Botrytis cinerea. Phosphorylation of S506 residue in the C-terminal calmodulin-binding domain of DGK5β contributes to the activation of DGK5β to produce PA. These findings suggest that DGK5β-derived PA regulates ROS production by inhibiting RBOHD protein degradation, elucidating the role of PA-ROS interplay in immune response regulation.

Prognostic factors for invasive mucinous adenocarcinoma of the lung: systematic review and meta-analysis

BackgroundInvasive mucinous adenocarcinoma of the lung (IMA) is a unique and rare subtype of lung adenocarcinoma with poorly defined prognostic factors and highly controversial studies. Hence, this study aimed to comprehensively identify and summarize the prognostic factors associated with IMA.MethodsA comprehensive search of relevant literature was conducted in the PubMed, Embase, Cochrane, and Web of Science databases from their inception until June 2023. The pooled hazard ratio (HR) and corresponding 95% confidence intervals (CI) of overall survival (OS) and/or disease-free survival (DFS) were obtained to evaluate potential prognostic factors.ResultsA total of 1062 patients from 11 studies were included. In univariate analysis, we found that gender, age, TNM stage, smoking history, lymph node metastasis, pleural metastasis, spread through air spaces (STAS), tumor size, pathological grade, computed tomography (CT) findings of consolidative-type morphology, pneumonia type, and well-defined heterogeneous ground-glass opacity (GGO) were risk factors for IMA, and spiculated margin sign was a protective factor. In multivariate analysis, smoking history, lymph node metastasis, pathological grade, STAS, tumor size, and pneumonia type sign were found to be risk factors. There was not enough evidence that epidermal growth factor receptor (EGFR) mutations, anaplastic lymphoma kinase (ALK) mutations, CT signs of lobulated margin, and air bronchogram were related to the prognosis for IMA.ConclusionIn this study, we comprehensively analyzed prognostic factors for invasive mucinous adenocarcinoma of the lung in univariate and multivariate analyses of OS and/or DFS. Finally, 12 risk factors and 1 protective factor were identified. These findings may help guide the clinical management of patients with invasive mucinous adenocarcinoma of the lung.

Abstract TMP3: Overexpression of Alk1 in Brain Endothelial Cells Alleviates the Severity of Brain Arteriovenous Malformations in Alk1 Mutant Mice

Background and purpose: Brain arteriovenous malformation (bAVM) can cause life threatening intra-cranial hemorrhage. Currently, there is no effective medical therapy available to treat bAVM patients. Mutation of activin receptor-like kinase 1 ( Alk1 also called ACVRL1 ) causes a familiar form of bAVM. Genetically overexpression of Alk1 in endothelial cells (ECs) recurs the phenotype of Alk1 deficient mice. We hypothesize that transduction of Alk1 gene into brain ECs using an adeno associated viral vector (AAV) may lead to cure of bAVM in Alk1 mutant mice. Methods: To identify a AAV capsid that can transduce brain ECs after intravenous (i.v.) delivery, several engineered AAV capsids were screened. A single-stranded CBA promoter driven tdTomato transgene was packaged in these capsids and delivered i.v. to wild-type mice. Tissues were collected 4 weeks later. After identifying a capsid, cc84, that can transduce brain ECs effectively after i.v. deliver, we package CMV-Alk1 transgene into AAV.cc84. Brain AVMs were induced on PdgfbiCre; Alk1 f/f mice through intra-brain injection of AAV1-VEGF followed by intraperitoneal injection of 1.25 mg/25g tamoxifen two weeks later. AAV.cc84-Alk1 was delivered to PdgfbiCre; Alk1 f/f mice through i.v. injection at the time of tamoxifen treatment Histological analyses were used to analyze viral transduction in the brain and liver, vessel density, and abnormal vessels in the brain and liver inflammation. Liver and kidney function were analyzed by colorimetric assays for Alkaline Phosphatase Activity (ALP), Alanine Transaminase Activity ALT), and Creatinine levels (Cr). Results: After i.v. injection, AAV-cc84 transduced a high percentage of brain ECs and a few hepatocytes. AAV.cc84-Alk1 treatment reduced vessel density (p=0.008), abnormal vessels (p=0.034), mouse mortality rates (20% vs 60% respectively) compared to the AAV.cc84-RFP (control vector) treated PdgfbiCre; Alk1 f/f mice. The levels of ALP, ALT and Cr were similar between AAV injected and uninjected mice. Conclusion: AAV.cc84 mediated EC overexpression of Alk1 reduced bAVM severity in Alk1 deficient mice indicating that AAV.cc84 is a promising gene therapy vector to treat bAVMs.

Regulation of SOCS3-STAT3 in urate-induced cytokine production in human myeloid cells

ObjectiveHyperuricaemia is necessary for gout. High urate concentrations have been linked to inflammation in mononuclear cells. Here, we explore the role of the suppressor of cytokine signaling 3 (SOCS3) in urate-induced inflammation. MethodsPeripheral blood mononuclear cells (PBMCs) from gout patients, hyperuricemic and normouricemic individuals were cultured for 24h with varying concentrations of soluble urate, followed by 24h restimulation with lipopolysaccharides (LPS)±monosodium urate (MSU) crystals. Transcriptomic profiling was performed using RNA-Sequencing. DNA methylation was assessed using Illumina Infinium® MethylationEPIC BeadChip system (EPIC array). Phosphorylation of signal transducer and activator of transcription 3 (STAT3) was determined by flow cytometry. Cytokine responses were also assessed in PBMCs from patients with JAK2 V617F tyrosine kinase mutation. ResultsPBMCs pre-treated with urate produced more interleukin-1beta (IL-1β) and interleukin-6 (IL-6) and less interleukin-1 receptor anatagonist (IL-1Ra) after LPS simulation. In vitro, urate treatment enhanced SOCS3 expression in control monocytes but no DNA methylation changes were observed at the SOCS3 gene. A dose-dependent reduction in phosphorylated STAT3 concomitant with a decrease in IL-1Ra was observed with increasing concentrations of urate. PBMCs with constitutively activated STAT3 (JAK2 V617F mutation) could not be primed by urate. ConclusionIn vitro, urate exposure increased SOCS3 expression, while urate priming, and subsequent stimulation resulted in decreased STAT3 phosphorylation and IL-1Ra production. There was no evidence that DNA methylation constitutes a regulatory mechanism of SOCS3. Elevated SOCS3 and reduced pSTAT3 could play a role in urate-induced hyperinflammation since urate priming had no effect in PBMCs from patients with constitutively activated STAT3.

The Activation of the Fibrodysplasia Ossificans Progressiva-Inducing ALK2-R206H Mutant Depends on the Distinct Homo-Oligomerization Patterns of ACVR2B and ACVR2A.

Mutations in activin-like kinase 2 (ALK2), e.g., ALK2-R206H, induce aberrant signaling to SMAD1/5/8, leading to Fibrodysplasia Ossificans Progressiva (FOP). In spite of extensive studies, the underlying mechanism is still unclear. Here, we quantified the homomeric and heteromeric interactions of ACVR2A, ACVR2B, ALK2-WT, and ALK2-R206H by combining IgG-mediated immobilization of one receptor with fluorescence recovery after photobleaching (FRAP) measurements on the lateral diffusion of a co-expressed receptor. ACVR2B formed stable homomeric complexes that were enhanced by Activin A (ActA), while ACVR2A required ActA for homodimerization. ALK2-WT, but not ALK2-R206H, exhibited homomeric complexes unaffected by ActA. ACVR2B formed ActA-enhanced heterocomplexes with ALK2-R206H or ALK2-WT, while ACVR2A interacted mainly with ALK2-WT. The extent of the homomeric complex formation of ACVR2A or ACVR2B was reflected in their ability to induce the oligomerization of ALK2-R206H and ALK2-WT. Thus, ACVR2B, which forms dimers without ligand, induced ActA-independent ALK2-R206H clustering but required ActA for enhancing the oligomerization of the largely dimeric ALK2-WT. In contrast, ACVR2A, which undergoes homodimerization in response to ActA, required ActA to induce ALK2-R206H oligomerization. To investigate whether these interactions are translated into signaling, we studied signaling by the FOP-inducing hyperactive ALK2-R206H mutant, with ALK2-WT signaling as control. The activation of SMAD1/5/8 signaling in cells expressing ALK2-R206H alone or together with ACVR2A or ACVR2B was measured by blotting for pSMAD1/5/8 and by transcriptional activation assays using BRE-Luc reporter. In line with the biophysical studies, ACVR2B activated ALK2-R206H without ligand, while activation by ACVR2A was weaker and required ActA. We propose that the homodimerization of ACVR2B or ACVR2A dictates their ability to recruit ALK2-R206H into higher complexes, enabling the homomeric interactions of ALK2-R206H receptors and, subsequently, their activation.

How we treat polycythemia vera

Polycythemia vera is a disease known since ancient times, however, until recent decades, diagnosis was carried out by exclusion, and therapy was symptomatic. The discovery of the pathogenetic role of mutations in the Janus kinase II gene has led to the possibility of establishing a diagnosis based not only on morphology, but also on genetic verification and to the development of directed targeted therapy, which is much more effective than previously used methods. The introduction of molecular genetic screening led to the need for a differential diagnosis with familial erythrocytosis, and the lessons of the coronavirus pandemic revealed the presence in the population of a significant proportion of patients with erythrocytosis due to the carriage of gene polymorphisms associated with familial hemochromatosis. The article presents our own personalized algorithms for the diagnosis and treatment of polycythemia vera and the results of their use, demonstrating the possibility of a two-fold reduction in the incidence of thrombosis and an increase in overall survival.