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Thrombopoietin (Tpo) is the primary regulator of megakaryocyte and platelet numbers and is required for haematopoetic stem cell maintenance. Tpo functions by binding its receptor (TpoR, a homodimeric Class I cytokine receptor) and initiating cell proliferation or differentiation. Here we characterise the murine Tpo:TpoR signalling complex biochemically and structurally, using cryo-electron microscopy. Tpo uses opposing surfaces to recruit two copies of receptor, forming a 1:2 complex. Although it binds to the same, membrane-distal site on both receptor chains, it does so with significantly different affinities and its highly glycosylated C-terminal domain is not required. In one receptor chain, a large insertion, unique to TpoR, forms a partially structured loop that contacts cytokine. Tpo binding induces the juxtaposition of the two receptor chains adjacent to the cell membrane. The therapeutic agent romiplostim also targets the cytokine-binding site and the characterisation presented here supports the future development of improved TpoR agonists.The haematopoietic cytokine thrombopoietin (Tpo) is the primary regulator of megakaryocyte and platelet numbers. Here authors present a structural and biochemical characterization of how Tpo binds to its receptor to induce signaling. [ABSTRACT FROM AUTHOR]

The inhibition of protein tyrosine phosphatases 1B (PTP1B) and N2 (PTPN2) has emerged as an exciting approach for bolstering T cell anti-tumor immunity. ABBV-CLS-484 is a PTP1B/PTPN2 inhibitor in clinical trials for solid tumors. Here we have explored the therapeutic potential of a related small-molecule-inhibitor, Compound-182. We demonstrate that Compound-182 is a highly potent and selective active site competitive inhibitor of PTP1B and PTPN2 that enhances T cell recruitment and activation and represses the growth of tumors in mice, without promoting overt immune-related toxicities. The enhanced anti-tumor immunity in immunogenic tumors can be ascribed to the inhibition of PTP1B/PTPN2 in T cells, whereas in cold tumors, Compound-182 elicited direct effects on both tumor cells and T cells. Importantly, treatment with Compound-182 rendered otherwise resistant tumors sensitive to α-PD-1 therapy. Our findings establish the potential for small molecule inhibitors of PTP1B and PTPN2 to enhance anti-tumor immunity and combat cancer. Here, the authors demonstrate that inhibition of PTP1B and PTPN2 in tumor cells and T-cells with a small molecule inhibitor represses the growth of immunogenic and cold tumors, and enhances response to anti-PD-1 immunotherapy without promoting immune-related toxicities. [ABSTRACT FROM AUTHOR]

Protein Tyrosine Phosphatase 1B (PTP1B) is the prototypical protein tyrosine phosphatase and plays an essential role in the regulation of several kinase-driven signalling pathways. PTP1B displays a preference for bisphosphorylated substrates. Here we identify PTP1B as an inhibitor of IL-6 and show that, in vitro, it can dephosphorylate all four members of the JAK family. In order to gain a detailed understanding of the molecular mechanism of JAK dephosphorylation, we undertook a structural and biochemical analysis of the dephosphorylation reaction. We identified a product-trapping PTP1B mutant that allowed visualisation of the tyrosine and phosphate products of the reaction and a substrate-trapping mutant with a vastly decreased off-rate compared to those previously described. The latter mutant was used to determine the structure of bisphosphorylated JAK peptides bound to the enzyme active site. These structures revealed that the downstream phosphotyrosine preferentially engaged the active site, in contrast to the analogous region of IRK. Biochemical analysis confirmed this preference. In this binding mode, the previously identified second aryl binding site remains unoccupied and the non-substrate phosphotyrosine engages Arg47. Mutation of this arginine disrupts the preference for the downstream phosphotyrosine. This study reveals a previously unappreciated plasticity in how PTP1B interacts with different substrates. Structural and biochemical characterization of the phosphastase and immune checkpoint PTP1B reveals the molecular basis of PTBP1B/JAK interaction and plasticity of substrate recognition by PTP1B. [ABSTRACT FROM AUTHOR]

Ectopic pregnancy (EP) is a term used to describe any pregnancy which does not implant into the uterine cavity. There are several types of EPs: tubal, interstitial, ovarian, abdominal, heterotopic, cervical, and cesarean scar. Ectopic pregnancies can acutely rupture and are the number one cause of maternal death in the first trimester of pregnancy. Therefore, prompt recognition and accurate localization have significant clinical implications on patient outcome. Unfortunately, EPs have many mimickers, which can make the diagnosis challenging in certain cases. In this review, we aim to describe and illustrate sonographic findings of each type of EP, as well as present mimickers and various imaging pitfalls. We will clarify how to avoid potential misdiagnoses that could adversely affect patient outcomes. Lastly, we will briefly address management of each type of EP and discuss potential complications. [ABSTRACT FROM AUTHOR]

Suppressor of cytokine signaling (SOCS)2 protein is a key negative regulator of the growth hormone (GH) and Janus kinase (JAK)-Signal Transducers and Activators of Transcription (STAT) signaling cascade. The central SOCS2-Src homology 2 (SH2) domain is characteristic of the SOCS family proteins and is an important module that facilitates recognition of targets bearing phosphorylated tyrosine (pTyr) residues. Here we identify an exosite on the SOCS2-SH2 domain which, when bound to a non-phosphorylated peptide (F3), enhances SH2 affinity for canonical phosphorylated ligands. Solution of the SOCS2/F3 crystal structure reveals F3 as an α-helix which binds on the opposite side of the SH2 domain to the phosphopeptide binding site. F3:exosite binding appears to stabilise the SOCS2-SH2 domain, resulting in slower dissociation of phosphorylated ligands and consequently, enhances binding affinity. This biophysical enhancement of SH2:pTyr binding affinity translates to increase SOCS2 inhibition of GH signaling. SOCS2 is a key regulator of growth hormone and cytokine signaling, which recognizes phosphotyrosine (pTyr)-modified targets via a central SH2 domain. Here, the authors discover and characterize an exosite on this SH2 domain that can bind a non-phosphorylated peptide to enhance SOCS2:pTyr affinity. [ABSTRACT FROM AUTHOR]

The SH2B family of adaptor proteins, SH2-B, APS, and LNK are key modulators of cellular signalling pathways. Whilst SH2-B and APS have been partially structurally and biochemically characterised, to date there has been no such characterisation of LNK. Here we present two crystal structures of the LNK substrate recognition domain, the SH2 domain, bound to phosphorylated motifs from JAK2 and EPOR, and biochemically define the basis for target recognition. The LNK SH2 domain adopts a canonical SH2 domain fold with an additional N-terminal helix. Targeted analysis of binding to phosphosites in signalling pathways indicated that specificity is conferred by amino acids one- and three-residues downstream of the phosphotyrosine. Several mutations in LNK showed impaired target binding in vitro and a reduced ability to inhibit signalling, allowing an understanding of the molecular basis of LNK dysfunction in variants identified in patients with myeloproliferative disease. LNK is a potent negative regulator of cytokine signaling implicated in blood cells proliferation. Here the authors present structures of the substrate recognition (SH2) domain of LNK in complex with phosphorylated motifs from JAK2 and EPOR; providing insight into its binding specificity and mode of action. [ABSTRACT FROM AUTHOR]

Introduction: Juvenile idiopathic arthritis (JIA) is a chronic rheumatic disease, whose multifaceted care path can lead to significant expenditure for the healthcare system. We aim to assess the real-world healthcare resource use (HCRU) and associated cost for children with JIA in a single center in Canada. Methods: A single-center consecutive cohort of newly diagnosed patients with JIA attending the pediatric rheumatology clinic from 2011 to 2019 was identified using an administrative data algorithm and electronic medical charts. HCRU was estimated from six administrative health databases that included hospital admissions, emergency, outpatient care, practitioners' visits, medication, and laboratory and imaging tests. Costs were assigned using appropriate sources. We reported the yearly overall and JIA-associated HCRU and costs 5 years prior to and 6 years after the first visit to the pediatric rheumatologist. The Zhao and Tian estimator was used to calculate cumulative mean costs over a 6-year timeframe. Results were stratified by disease subtype. Results: A total of 389 patients were identified. The yearly total overall mean costs per patient ranged between $804 and $4460 during the 5 years prior to the first visit to the pediatric rheumatologist and $8529 and $10,651 for the 6 years after. Medication cost, driven by use of biologic therapies, and outpatient visits were the greatest contributor to the total cost. The overall cumulative mean cost for 6 years of care was $48,649 per patient, while the JIA-associated cumulative mean cost was $26,820 per patient. During the first year of rheumatology care, systemic onset JIA had the highest cumulative mean overall cost, while oligoarticular JIA had the lowest cumulative mean cost. Conclusion: The care pathway for children with JIA can be expensive, and complex—and varies by JIA subtype. Although the yearly total mean cost per patient was constant, the distribution of costs changes over time with the introduction of biologic therapies later in the care pathway. This study provides a better understanding of the JIA costs profile and can help inform future economic studies. [ABSTRACT FROM AUTHOR]

The objective of the current study is to evaluate the potency of halogen-furan-2(5H)-one-type derivatives against human cancer cell lines. Four known bromofuran-2(5H)-one-type derivatives, as well as five new and two known bromo-4-(phenylamino)furan-2(5H)-one-type compounds and six novel and two known halogen-4-alkyl-5-phenyl-3-(phenylamino)furan-2(5H)-one-type derivatives, were synthesized and evaluated for their anticancer activity against prostate (PC-3) and colon (HCT-116) human cancer cell lines. The results showed that only the bromofuran-2(5H)-ones were cytotoxic in both cell lines. Three of these displayed particularly useful antiproliferative activities, in both cancer cells evaluated. (E)-5-(Bromomethylene)furan-2-(5H)-one was the most active against PC-3 (IC50 0.93 ± 0.02 μM) while 3,4-dibromofuran-2(5H)-one was the most active against HCT-116 (IC50 0.4 ± 0.04 μM). Furthermore, flow cytometry studies revealed that the bromofuran-2(5H)-ones induced cell death by apoptosis. Also, it was found that the cytotoxic furanones induced lipid peroxidation, determined by TBARS assay. Thus, cytotoxicity of the active compounds could be associated with ROS production. Additionally, it must be taken into account that all cytotoxic compounds contain an electrophilic carbon atom in position 4, which can explain, through a non-specific reactivity with nucleophiles, the cytotoxic activity of these compounds. [ABSTRACT FROM AUTHOR]

The internal medicine (IM) subinternship has been a long-established clinical experience in the final phase of medical school deemed by key stakeholders as a crucial rotation to prepare senior medical students for internship. Medical education has changed greatly since the first national curriculum for this course was developed in 2002 by the Clerkship Directors in Internal Medicine (CDIM). Most notably, competency-based medical education (CBME) has become a fixture in graduate medical education and has gradually expanded into medical school curricula. Still, residency program directors and empirical studies have identified gaps and inconsistencies in knowledge and skills among new interns. Recognizing these gaps, the Association of Program Directors in Internal Medicine (APDIM) surveyed its members in 2010 and identified four core skills essential for intern readiness. The Association of American Medical Colleges (AAMC) also published 13 core entrustable professional activities (EPAs) for entering residency to be expected of all medical school graduates. Results from the APDIM survey along with the widespread adoption of CBME informed this redesign of the IM subinternship curriculum. The authors provide an overview of this new guide developed by the Alliance for Academic Internal Medicine (AAIM) Medical Student-to-Resident Interface Committee (MSRIC). [ABSTRACT FROM AUTHOR]

Pathogenic variation in MAPT, GRN, and C9ORF72 accounts for at most only half of frontotemporal lobar degeneration (FTLD) cases with a family history of neurological disease. This suggests additional variants and genes that remain to be identified as risk factors for FTLD. We conducted a case-control genetic association study comparing pathologically diagnosed FTLD patients (n = 94) to cognitively normal older adults (n = 3541), and found suggestive evidence that gene-wide aggregate rare variant burden in MFSD8 is associated with FTLD risk. Because homozygous mutations in MFSD8 cause neuronal ceroid lipofuscinosis (NCL), similar to homozygous mutations in GRN, we assessed rare variants in MFSD8 for relevance to FTLD through experimental follow-up studies. Using post-mortem tissue from middle frontal gyrus of patients with FTLD and controls, we identified increased MFSD8 protein levels in MFSD8 rare variant carriers relative to non-variant carrier patients with sporadic FTLD and healthy controls. We also observed an increase in lysosomal and autophagy-related proteins in MFSD8 rare variant carrier and sporadic FTLD patients relative to controls. Immunohistochemical analysis revealed that MFSD8 was expressed in neurons and astrocytes across subjects, without clear evidence of abnormal localization in patients. Finally, in vitro studies identified marked disruption of lysosomal function in cells from MFSD8 rare variant carriers, and identified one rare variant that significantly increased the cell surface levels of MFSD8. Considering the growing evidence for altered autophagy in the pathogenesis of neurodegenerative disorders, our findings support a role of NCL genes in FTLD risk and suggest that MFSD8-associated lysosomal dysfunction may contribute to FTLD pathology. [ABSTRACT FROM AUTHOR]

The SOCS family of proteins are negative-feedback inhibitors of signalling induced by cytokines that act via the JAK/STAT pathway. SOCS proteins can act as ubiquitin ligases by recruiting Cullin5 to ubiquitinate signalling components; however, SOCS1, the most potent member of the family, can also inhibit JAK directly. Here we determine the structural basis of both these modes of inhibition. Due to alterations within the SOCS box domain, SOCS1 has a compromised ability to recruit Cullin5; however, it is a direct, potent and selective inhibitor of JAK catalytic activity. The kinase inhibitory region of SOCS1 targets the substrate binding groove of JAK with high specificity and thereby blocks any subsequent phosphorylation. SOCS1 is a potent inhibitor of the interferon gamma (IFNγ) pathway, however, it does not bind the IFNγ receptor, making its mode-of-action distinct from SOCS3. These findings reveal the mechanism used by SOCS1 to inhibit signalling by inflammatory cytokines. [ABSTRACT FROM AUTHOR]

Mesenteric abnormalities are often incidentally discovered on cross-sectional imaging performed during daily clinical practice. Findings can range from the vague "misty mesentery" to solid masses, and the possible etiologic causes encompass a wide spectrum of underlying pathologies including infectious, inflammatory, and neoplastic processes. Unfortunately, the clinical and imaging findings are often non-specific and may overlap. This article discusses the various diseases that result in mesenteric abnormalities. It provides a framework to non-invasively differentiate these entities, when possible. [ABSTRACT FROM AUTHOR]

2-Oxoglutarate (2OG)-dependent oxygenases have important roles in the regulation of gene expression via demethylation of N-methylated chromatin components and in the hydroxylation of transcription factors and splicing factor proteins. Recently, 2OG-dependent oxygenases that catalyse hydroxylation of transfer RNA and ribosomal proteins have been shown to be important in translation relating to cellular growth, TH17-cell differentiation and translational accuracy. The finding that ribosomal oxygenases (ROXs) occur in organisms ranging from prokaryotes to humans raises questions as to their structural and evolutionary relationships. In Escherichia coli, YcfD catalyses arginine hydroxylation in the ribosomal protein L16; in humans, MYC-induced nuclear antigen (MINA53; also known as MINA) and nucleolar protein 66 (NO66) catalyse histidine hydroxylation in the ribosomal proteins RPL27A and RPL8, respectively. The functional assignments of ROXs open therapeutic possibilities via either ROX inhibition or targeting of differentially modified ribosomes. Despite differences in the residue and protein selectivities of prokaryotic and eukaryotic ROXs, comparison of the crystal structures of E. coli YcfD and Rhodothermus marinus YcfD with those of human MINA53 and NO66 reveals highly conserved folds and novel dimerization modes defining a new structural subfamily of 2OG-dependent oxygenases. ROX structures with and without their substrates support their functional assignments as hydroxylases but not demethylases, and reveal how the subfamily has evolved to catalyse the hydroxylation of different residue side chains of ribosomal proteins. Comparison of ROX crystal structures with those of other JmjC-domain-containing hydroxylases, including the hypoxia-inducible factor asparaginyl hydroxylase FIH and histone N?-methyl lysine demethylases, identifies branch points in 2OG-dependent oxygenase evolution and distinguishes between JmjC-containing hydroxylases and demethylases catalysing modifications of translational and transcriptional machinery. The structures reveal that new protein hydroxylation activities can evolve by changing the coordination position from which the iron-bound substrate-oxidizing species reacts. This coordination flexibility has probably contributed to the evolution of the wide range of reactions catalysed by oxygenases. [ABSTRACT FROM AUTHOR]

The inhibitory protein SOCS3 plays a key part in the immune and hematopoietic systems by regulating signaling induced by specific cytokines. SOCS3 functions by inhibiting the catalytic activity of Janus kinases (JAKs) that initiate signaling within the cell. We determined the crystal structure of a ternary complex between mouse SOCS3, JAK2 (kinase domain) and a fragment of the interleukin-6 receptor β-chain. The structure shows that SOCS3 binds JAK2 and receptor simultaneously, using two opposing surfaces. While the phosphotyrosine-binding groove on the SOCS3 SH2 domain is occupied by receptor, JAK2 binds in a phosphoindependent manner to a noncanonical surface. The kinase-inhibitory region of SOCS3 occludes the substrate-binding groove on JAK2, and biochemical studies show that it blocks substrate association. These studies reveal that SOCS3 targets specific JAK-cytokine receptor pairs and explains the mechanism and specificity of SOCS action. [ABSTRACT FROM AUTHOR]

Kawasaki disease (KD) is an acute systemic vasculitis affecting young children and is rising in incidence worldwide. It is most common in children <5 years of age, males and those of Asian ethnicity. It is an important cause of acquired heart disease in children. Standard treatment with high-dose aspirin (acetylsalicylic acid; ASA) and intravenous immune globulin (IVIG) has been shown to decrease the rate of coronary artery aneurysm development. Anti- coagulation has an important place in the management of KD, although guidance based on evidence is lacking. Treatment of refractory KD is an area under intense study and may include IVIG, corticosteroids and/or tumour necrosis factor (TNF)-oc inhibitors among immunosuppressive agents. Acute complications of KD iinclude myocarditis/KD shock syndrom and macrophage activation syndrome, which necessitate appropriate awareness in order ot initiate proper management. [ABSTRACT FROM AUTHOR]

The article summarizes the survey related to medical professionals practising pediatric interventional radiology, conducted by the SPR vascular interventional radiology committee. The survey which was announced at the 48th Annual SPR in New Orleans was conducted from 18 February 2005 through 18 May 2005.

Early studies of the free-living nematode C. elegans informed us how BCL-2-regulated apoptosis in humans is regulated. However, subsequent studies showed C. elegans apoptosis has several unique features compared with human apoptosis. To date, there has been no detailed analysis of apoptosis regulators in nematodes other than C. elegans. Here, we discovered BCL-2 orthologues in 89 free-living and parasitic nematode taxa representing four evolutionary clades (I, III, IV and V). Unlike in C. elegans, 15 species possess multiple (two to five) BCL-2-like proteins, and some do not have any recognisable BCL-2 sequences. Functional studies provided no evidence that BAX/BAK proteins have evolved in nematodes, and structural studies of a BCL-2 protein from the basal clade I revealed it lacks a functionally important feature of the C. elegans orthologue. Clade I CED-4/APAF-1 proteins also possess WD40-repeat sequences associated with apoptosome assembly, not present in C. elegans, or other nematode taxa studied. Young et al. report on the diversity in regulation of nematode apoptosis. Results indicate that the apoptotic pathways of C. elegans are not fully representative of nematodes generally. [ABSTRACT FROM AUTHOR]

AspH is an endoplasmic reticulum (ER) membrane-anchored 2-oxoglutarate oxygenase whose C-terminal oxygenase and tetratricopeptide repeat (TPR) domains present in the ER lumen. AspH catalyses hydroxylation of asparaginyl- and aspartyl-residues in epidermal growth factor-like domains (EGFDs). Here we report crystal structures of human AspH, with and without substrate, that reveal substantial conformational changes of the oxygenase and TPR domains during substrate binding. Fe(II)-binding by AspH is unusual, employing only two Fe(II)-binding ligands (His679/His725). Most EGFD structures adopt an established fold with a conserved Cys1–3, 2–4, 5–6 disulfide bonding pattern; an unexpected Cys3–4 disulfide bonding pattern is observed in AspH-EGFD substrate complexes, the catalytic relevance of which is supported by studies involving stable cyclic peptide substrate analogues and by effects of Ca(II) ions on activity. The results have implications for EGFD disulfide pattern processing in the ER and will enable medicinal chemistry efforts targeting human 2OG oxygenases. AspH catalyses hydroxylation of asparagine and aspartate residues in epidermal growth factor-like domains (EGFDs). Here, the authors present crystal structures of AspH with and without substrates and show that AspH uses EFGD substrates with a non-canonical disulfide pattern. [ABSTRACT FROM AUTHOR]

The authors discuss a study on juvenile dermatomyositis (JDM), by N. Luca and colleagues, published in "Nature Reviews Rheumatology." They describe the Paediatric Rheumatology International Trials Organisation's (PRINTO) criteria for clinically inactive disease in JDM. They also explain the factors that should be considered to establish the validity of the PRINTO criteria for inactive disease. Clinical information on JDM is also given.

A correction to the article "Pediatric interventional radiology work force survey summary" that was published in the January 3, 2007 issue is presented.