C2 Ligand Research Articles

Multifactorial determinants of NK cell repertoire organization: insights into age, sex, KIR genotype, HLA typing, and CMV influence.

Polymorphisms in the KIR and HLA genes contribute to the diversity of the NK cell repertoire. Extrinsic factors also play a role in modifying this repertoire. The best example is cytomegalovirus, which promotes the expansion of memory-like NK cells. However, the mechanisms governing this phenotypic structure are poorly understood. Furthermore, the influence of age and sex has been understudied. In this study, we examined these parameters in a cohort of 200 healthy volunteer blood donors, focusing on the major inhibitory KIR receptors and CD94/NKG2A, as well as the differentiation marker CD57 and the memory-like population marker NKG2C. Flow cytometry and two joint analyses, unsupervised and semi-supervised, helped define the impact of various intrinsic and extrinsic markers on the phenotypic structure of the NK cell repertoire. In the KIR NK cell compartment, the KIR3DL1 gene is crucial, as unexpressed alleles lead to a repertoire dominated by KIR2D interacting only with HLA-C ligands, whereas an expressed KIR3DL1 gene allows for a greater diversity of NK cell subpopulations interacting with all HLA class I ligands. KIR2DL2 subsequently favors the KIR2D NK cell repertoire specific to C1/C2 ligands, whereas its absence promotes the expression of KIR2DL1 specific to the C2 ligand. The C2C2Bw4+ environment, marked by strong -21T motifs, favors the expansion of the NK cell population expressing only CD57, whereas the absence of HLA-A3/A11 ligands favors the population expressing only NKG2A, a population highly represented within the repertoire. The AA KIR genotype favors NK cell populations without KIR and NKG2A receptors, whereas the KIR B+ genotypes favor populations expressing KIR and NKG2A. Interestingly, we showed that women have a repertoire enriched in CD57- NK cell populations, while men have more CD57+ NK cell subpopulations. Overall, our data demonstrate that the phenotypic structure of the NK cell repertoire follows well-defined genetic rules and that immunological history, sex, and age contribute to shaping this NK cell diversity. These elements can contribute to the better selection of hematopoietic stem cell donors and the definition of allogeneic NK cells for cell engineering in NK cell-based immunotherapy approaches.cters are displayed correctly.

Killer immunoglobulin-like receptors and HLA C1/C2 genes diversities and susceptibility to acute myeloid leukemia in Saudi Arabian patients

ObjectiveNatural Killer cells activation depends on the interaction with killer cell immunoglobin-like receptors (KIRs), which bind the peptide-binding region of several class-I Human Leukocyte Antigens (HLA class-I). In addition, KIR and HLA loci are highly polymorphic and display significant variation between individuals. MethodsWe attempted to investigate the association of 16 KIR complexes and the HLA-C1 and C2 ligands to the genetic predisposition and development of Acute Lymphoblastic leukemia (AML) in Saudi Arabian patients. We genotyped 16 KIR genes for 100 patients with Acute Lymphoblastic leukemia and 114 healthy controls, and all samples were considered for evaluating combined KIR-HLA C1/C2 associations. ResultsKIR genotype frequency differed significantly between AML patients and healthy controls. KIR2DL1, KIR2DL5, and KIR2DS2 increased significantly in patients than in controls. The 2DL5 gene contributed to the highest risk of AML (OR = 2.9906, p < 0.00059), followed by 2DS2 (OR = 1.8068; p < 0.039). However, the incidence of KIR 2DL3, KIR2DS4, and KIR2DL2 was significantly elevated in healthy controls compared to myeloid leukemia patients. The distributions of HLA-C1 and C2 ligands were not significantly different between patients and controls. Analyses of different combinations of KIR/HLA class I ligand profile show that the frequency of KIR2DL3 + in the presence of the allotype C1 was decreased among AML patients compared to controls. Similarly, KIR2DL3 and KIR2DL2/2DL3, when combined with their respective ligands, HLA-C2/C1, were significantly less prevalent in AML patients when compared to controls. ConclusionOur data suggested a potential predictive role for a specific KIR genotype, and HLA-I encoding genes to AML risk.

(NHC)Ni(II)-Directed Insertions and Higher Substituted Olefin Synthesis from Simple Olefins

ConspectusWell-controlled olefin insertion is critical for achieving catalytic and productive bulk and fine-chemical synthesis. Developing efficient and selective methods for meeting diverse insertion demands is extremely noteworthy, as it supports numerous transformations. The challenges are related to improving catalyst performance and selectivity control and uniting previously unreactive substrate pairs to achieve higher molecular structural complexity and utility. Nickel catalysts have received persistent attention in higher substituted olefin synthesis and polymerization, and numerous new strategies have been established to fulfill the ever-changing demands. This Account focuses on the recent progress based on N-heterocyclic carbene (NHC) ligands and nickel catalysts in our laboratory in using simple terminal olefins as olefin donors or acceptors.It begins with a brief history of olefin codimerization and the major advances in hydrovinylation achieved by other research groups using ethylene as an olefin donor. It then describes problems related to the reductive elimination that can occur when both the hydrometalated alkene and NHC are on the catalyst. It emphasizes the impact of NHC catalyst generation methods on the competing reactivity. Next, it explains the principal challenges and great opportunities in using our method (with α-olefins as olefin donors and alkenyl sources) to replace intermolecular reductive hydroalkenylation reactions (which require rare and more expensive alkenyl halides and boronic acids as reactants, alongside a stoichiometric amount of metallic reagents). The Account then illustrates the potential uses of our method for solving challenging organic synthesis problems using tailor-made (NHC)Ni(II) catalysts to allow redox-neutral catalytic cycles based on high chemo- and regioselective cross-insertion controls. It shows that upon optimal steric and electronic cooperation between the NHC, olefin donor, and olefin acceptor, regiodivergent insertion and convergent synthesis can be achieved easily.In the course of our work, we uncovered several unique insights into regulating (anti-)Markovnikov hydronickelation, carbonickelation, hydrocarbonation, ring closure, 1,3-allyl shift, isomerization, and catalyst regeneration under green, neutral, and mild-temperature conditions. These insights are also outlined here, along with theoretical calculations that offer additional understandings of the insertion reactivity and selectivity differences observed between the NHC and the highly related phosphorus-based Ni(II) hydride-catalyzed cross-hydroalkenylation and cycloisomerization systems.Compared to traditional olefin and cyclic structure synthesis technology, such as olefin cross-metathesis, enyne cyclization, and cross-coupling reactions, the new catalyst systems often offer previously inaccessible product structural characteristics, substrate scope, and outcomes. In particular, the method is effective for the catalytic synthesis of unsymmetrical and functionalized 1,1-disubstituted olefins (a.k.a. gem-olefins), 1,4-dienes (a.k.a. skipped dienes), conjugated dienes, endo- and exocyclic olefins, fused and spiro rings, and aromatic products. These syntheses are variously achieved by cross-hydroalkenylation, insertion-induced rearrangement, cycloadditions, and other approaches inspired by our investigations and detailed in this Account. Cross-hydroalkenylation can be achieved with high enantioselectivity by application of carefully designed and structurally flexible C1 and C2 chiral NHC ligands, yielding a pool of chiral branched alkenes and 1,4-dienes directly from simple chemical feedstocks used in industry. This Account will draw further attention to green alkenylation and the related development of redox-neutral catalytic cycles.

Fragment-Based Approaches Identified Tecovirimat-Competitive Novel Drug Candidate for Targeting the F13 Protein of the Monkeypox Virus.

Monkeypox is a serious public health issue in tropical and subtropical areas. Antivirals that target monkeypox proteins might lead to more effective and efficient therapy. The F13 protein is essential for the growth and maturation of the monkeypox virus. F13 inhibition might be a viable therapeutic target for monkeypox. The in silico fragment-based drug discovery method for developing antivirals may provide novel therapeutic options. In this study, we generated 800 compounds based on tecovirimat, an FDA-approved drug that is efficacious at nanomolar quantities against monkeypox. These compounds were evaluated to identify the most promising fragments based on binding affinity and pharmacological characteristics. The top hits from the chemical screening were docked into the active site of the F13 protein. Molecular dynamics simulations were performed on the top two probable new candidates from molecular docking. The ligand-enzyme interaction analysis revealed that the C2 ligand had lower binding free energy than the standard ligand tecovirimat. Water bridges, among other interactions, were shown to stabilize the C2 molecule. Conformational transitions and secondary structure changes in F13 protein upon C2 binding show more native three-dimensional folding of the protein. Prediction of pharmacological properties revealed that compound C2 may be promising as a drug candidate for monkeypox fever. However, additional in vitro and in vivo testing is required for validation.

THERMODYNAMIC AND REACTIVITY ASPECT OF &amp;#946;-CYCLODEXTRINE INCLUSION COMPLEXES WITH COUMARIN DERIVATIVES

In this study, the thermodynamic and reactivity characteristics of coumarin-derived ligand inclusion complexes with βCD were described, in addition to the in situ reactivity of these ligands and their changes in the complex cavity. For this purpose, computational tools such as molecular docking, second order perturbative analysis (E2PERT), ONIOM2 (DFT/PM6) methods were employed to obtain the global and local reactivity indices, and thermodynamic parameters, in addition to non-covalent interaction (NCI) analysis. As a result, it can be observed that the inclusion complexes are stable and viable given the ability to form non-covalent interactions, but their formation is not spontaneous under the modeling conditions. The global and local reactivity indices show that the ligands change their chemical reactivity inside the inclusion complex, demonstrating that the studied ligands present AOX SET activity outside the cavity, and HAT activity inside the cavity, mainly the C1 and C3 ligands.

Ethane-Bridged Hybrid Monolithic Column with Large Mesopores for Boosting Top-Down Proteomic Analysis.

Top-down proteomics is challenged by the high complexity of biological samples. The coelution of intact proteins results in overlapped mass spectra, and hence, an increased peak capacity for protein separation is needed. Herein, ethane-bridged hybrid monoliths with well-defined large mesopores were successfully prepared based on the sol-gel condensation of 1,2-bis(trimethoxysilyl)ethane and tetramethoxysilane, followed by two-step base etching of the Si-O-Si domain while maintaining the Si-C-C-Si domain in the structure. Relatively homogeneous macropores of 1.1 μm and large mesopores of 24 nm were obtained, permitting fast mass transfer of large molecules and efficient diffusion without obstruction. The use of less hydrophobic C1 ligand further sharpened the peak shape and improved peak capacity. A 120 cm-long capillary column was used for top-down proteomic analysis of E. coli lysates under low backpressure with 16 MPa. High peak capacity of 646 was achieved within 240 min gradient. With MS/MS analysis, 959 proteoforms corresponding to 263 proteins could be unambiguously identified from E. coli lysates in a single run. Furthermore, to illustrate the separation performance for large proteoforms, such monoliths were applied to top-down analysis of the SEC fraction of E. coli lysates with Mw ranging from 30 to 70 kDa. With highly effective separation, 347 large proteoforms with Mw higher than 30 kDa were detected in the single 75 min run. These results showed great potential for top-down proteomic analysis in complex samples.

Determination of the effect of L. plantarum AB6-25, L. plantarum MK55 and S. boulardii T8-3C microorganisms on colon, cervix, and breast cancer cell lines: Molecular docking, and molecular dynamics study

Cancer constitutes an important part of the diseases that are caused all over the world. Due to the side effects of commonly used treatment options such as chemotherapy and radiotherapy, there has been a tendency to seek natural anticancer compounds. In this study, the cytotoxic effects of L. plantarum AB6-25, L. plantarum MK55, and S. boulardii T8-3C probiotic strains on HCT-116, HeLa, and MDA-MB-231 cell lines were determined. The effect of the microorganisms’ cell contents was also evaluated in 3D cancer cell lines. To evaluate the effect of microorganisms on metastasis, we applied to wound healing and invasion assays. At the same time, the cytotoxic effect of microorganisms on cancer cell lines was determined at the gene level using Real-Time qPCR. In addition, the effect of microorganisms on the expression of CASP3 protein in HeLa cells was also evaluated. At the last stage of the study, molecular docking and molecular dynamics simulation studies were carried out with the microorganism metabolites detected by QTOF-LC/MS. The results of the study showed that the most effective strain on HeLa and MDA-MB-231 cells was L. plantarum AB6-25 with a 91% and 80% inhibition rate, respectively, while L. plantarum MK55 had the highest cytotoxic effect on HCT-116 cells with a 69% inhibition rate. On the other hand, S. boulardii T8-3C had a weaker anticarcinogenic effect on cancer cell lines compared to the other two bacteria. According to the migration and invasion assays results, HCT-116 and MDA-MB-231 cells were the most effective bacteria in preventing L. plantarum MK55, and S. boulardii T8-3C metastasis in HeLa cells. As a result of gene expression analysis, microorganisms showed the greatest effect on apoptotic genes in HeLa cells. In HCT-116 and MDA-MB-231 cells, the expression level of apoptotic genes changed less. In the western blot analysis, L. plantarum AB6-25, L. plantarum MK55, and S. boulardii T8-3C cell contents expressed CASP3 at a higher level in the 2D HeLa cells compared to the 3D cells. The BAX protein and istamycin C1 ligand, which resulted in the binding energy of -8.23 kcal/mol, were determined as the molecules with the best anti-cancer effect. The results of in vitro studies have been supported by genetic expression analysis and molecular docking studies, and have shown the potential of microorganisms’ cell contents to be an anticancer agent.

Multiple CO2 reduction mediated by heteronuclear metal carbide cluster anions RhTaC2.

Noble metals dispersed on transition-metal carbides exhibit extraordinary activity in CO2 catalytic conversion and bimetallic carbides generated at the interface were proposed to contribute to the observed activity. Heteronuclear metal carbide clusters (HMCCs) that compositionally resemble the bimetallic carbides are suitable models to get a fundamental understanding of the reactivity of the related condensed-phase catalysts, while the reaction of HMCCs with CO2 has not been touched in the gas phase. Herein, benefiting from the newly designed double ion trap reactors, the reaction of laser-ablation generated and mass-selected RhTaC2- clusters with CO2 was studied. The experimental results identified that RhTaC2- can reduce four CO2 molecules consecutively and generate the product RhTaC2O4-. The pivotal roles of Rh-Ta synergy and the C2 ligand in driving CO2 reduction were rationalized by theoretical calculations. The presence of an attached CO unit on the product RhTaC2O4- was evidenced by the collision-induced dissociation experiment, providing a fundamental strategy to alleviate carbon deposition under a CO2 atmosphere at elevated temperatures.

Molecular dynamics simulation studies on binding of activator and inhibitor to Munc13-1 C1 in the presence of membrane

Munc13-1 is a presynaptic active zone protein that plays a critical role in priming the synaptic vesicle and releasing neurotransmitters in the brain. Munc13-1 acts as a scaffold and is activated when diacylglycerol (DAG)/phorbol ester binds to its C1 domain in the plasma membrane. Our previous studies showed that bryostatin 1 activated the Munc13-1, but resveratrol inhibited the phorbol ester-induced Munc13-1 activity. To gain structural insights into the binding of the ligand into Munc13-1 C1 in the membrane, we conducted 1.0 μs molecular dynamics (MD) simulation on Munc13-1 C1–ligand–lipid ternary system using phorbol 13-acetate, bryostatin 1 and resveratrol as ligands. Munc13-1 C1 shows higher conformational stability and less mobility along membrane with phorbol 13-acetate and bryostatin 1 than with resveratrol. Bryostatin 1 and phorbol ester remained in the protein active site, but resveratrol moved out of Munc13-1 C1 during the MD simulation. While bryostatin 1-bound Munc13-1 C1 showed two different positioning in the membrane, phorbol 13-acetate and resveratrol-bound Munc13-1 C1 only showed one positioning. Phorbol 13-acetate formed hydrogen bond with Ala-574 and Gly-589. Bryostatin 1 had more hydrogen bonds with Trp-588 and Arg-592 than with other residues. Resveratrol formed hydrogen bond with Ile-590. This study suggests that different ligands control Munc13-1 C1’s mobility and positioning in the membrane differently. Ligand also has a critical role in the interaction between Munc13-1 C1 and lipid membrane. Our results provide structural basis of the pharmacological activity of the ligands and highlight the importance of membrane in Munc13-1 activity. Communicated by Ramaswamy H. Sarma

NK Cell Subpopulations and Receptor Expression in Recovering SARS-CoV-2 Infection.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the pandemic of coronavirus disease (COVID-19). Whereas in most cases COVID-19 is asymptomatic or pauci-symptomatic, extremely severe clinical forms are observed. In this case, complex immune dysregulations and an excessive inflammatory response are reported and are the main cause of morbidity and mortality. Natural killer cells are key players in the control of viral infection, and their activity is regulated by a tight balance between activating and inhibitory receptors; an alteration of NK activity was suggested to be associated with the development of severe forms of COVID-19. In this study, we analyzed peripheral NK cell subpopulations and the expression of activating and inhibitory receptors in 30 patients suffering from neurological conditions who recovered from mild, moderate, or severe SARS-CoV-2 infection, comparing the results to those of 10 SARS-CoV-2-uninfected patients. Results showed that an expansion of NK subset with lower cytolytic activity and an augmented expression of the 2DL1 inhibitory receptor, particularly when in association with the C2 ligand (KIR2DL1-C2), characterized the immunological scenario of severe COVID-19 infection. An increase of NK expressing the ILT2 inhibitory receptor was instead seen in patients recovering from mild or moderate infection compared to controls. Results herein suggest that the KIR2DL1-C2 NK inhibitory complex is a risk factor toward the development of severe form of COVID-19. Our results confirm that a complex alteration of NK activity is present in COVID-19 infection and offer a molecular explanation for this observation.Supplementary InformationThe online version contains supplementary material available at 10.1007/s12035-021-02517-4.

Complex Conformational Dynamics of the Heart Failure-Associated Pre-miRNA-377 Hairpin Revealed by Single-Molecule Optical Tweezers.

Pre-miRNA-377 is a hairpin-shaped regulatory RNA associated with heart failure. Here, we use single-molecule optical tweezers to unzip pre-miRNA-377 and study its stability and dynamics. We show that magnesium ions have a strong stabilizing effect, and that sodium ions stabilize the hairpin more than potassium ions. The hairpin unfolds in a single step, regardless of buffer composition. Interestingly, hairpin folding occurs either in a single step (type 1) or through the formation of intermediates, in multiple steps (type 2) or gradually (type 3). Type 3 occurs only in the presence of both sodium and magnesium, while type 1 and 2 take place in all buffers, with type 1 being the most prevalent. By reducing the size of the native hairpin loop from fourteen to four nucleotides, we demonstrate that the folding heterogeneity originates from the large size of the hairpin loop. Further, while efficient pre-miRNA-377 binders are lacking, we demonstrate that the recently developed C2 ligand displays bimodal activity: it enhances the mechanical stability of the pre-miRNA-377 hairpin and perturbs its folding. The knowledge regarding pre-miRNA stability and dynamics that we provide is important in understanding its regulatory function and how it can be modulated to achieve a therapeutic effect, e.g., in heart failure treatment.

KIR- Ligand Mismatching Is Associated with Inferior Survival in Patients with Acute Leukemia Following T-Cell Replete Peripheral-Blood Stem Cell Haplo-Identical Transplantation with Post-Transplant Cyclophosphamide. a Study from the Acute Leukemia Working Party of the European Society for Blood and Marrow Transplantation (EBMT)

Background: Haplo-identical stem cell transplantation is increasingly been used in recent years in the treatment of acute leukemia. In particular, the use of T-cell replete grafts with post-transplant cyclophosphamide (PTCy) for prevention of graft-vs-host disease (GVHD) is becoming a valid treatment option with encouraging outcome. The initial studies used bone-marrow as the stem-cell source, but more recently, peripheral blood stem cells (PBSC) are also used. There is more limited data on the prognostic factors following haplo-identical transplantation with PBSC. Natural killer (NK) allo-reactivity as predicted by missing killer-cell immunoglobulin-like receptor (KIR) ligands in the recipients that are present in the donors has been shown to be an important factor in the outcome of T-cell depleted haplo-identical transplants. NK alloreactivity is associated with reduced relapse risk and improved survival in patients with AML, but not in patients with adult ALL. In addition, patients with donor NK alloreactivity had better engraftment and lower risk of GVHD. The role of NK cell allo-reactivity in the setting of T-cell replete haplo-identical transplant with PBSC and PTCy is unknown.Patients and Methods: The study included 238 patients, 139 male, 99 female, median age 45 years (range, 18-78) with AML (n=176) or ALL (n=62) who had T-replete haplo-identical transplant with PTCy between the years 2010-2015. All patients were given PBSC as their stem cell source. Patients were in CR1 (38%), CR2 (24%) or active disease (38%). Conditioning was myeloablative (47%) or reduced-intensity (53%). GVHD prevention included cyclosporine or tacrolimus with mycophenolate, in addition to PTCy, in 82%. KIR-ligand mismatching was predicted according to patient and donor HLA typing and correlated with transplantation outcomes. In all, 89 patients (37%) had a KIR mismatch in the GVHD direction, based on missing expression of C1, C2 or Bw4 ligands in the recipients that were expressed in their donors. There was no significant difference in patient characteristics between the group with and without KIR mismatch.Results: The median follow-up was 14 months (range, 1-50). Ninety-four percent of patients engrafted. The 2-year relapse and non-relapse mortality (NRM) rates in the entire group were 36% (95%CI, 29-42) and 22% (17-27), respectively. The leukemia-free (LFS) and overall survival (OS) rates were 43% (36-50) and 49% (42-56), respectively. Acute GVHD grade II-IV and chronic GVHD occurred in 34% (29-40) and 32% (26-39), respectively. The 2-year OS was 35% (22-47) in patients with KIR mismatch and 51% (42-60) in patients with no KIR-ligand mismatching (P=0.02). 2-year LFS rates were 27% (16-38) and 47% (38-56), respectively (P=0.003). Multivariate analysis identified AML (compared to ALL) (HR 0.51, P=0.008), active disease at transplantation (HR 5.03, P<0.001) and KIR mismatching (HR 1.60, P=0.03) as factors associated with 2-year OS. A center effect was also identified (P=0.05). The same factors predicted for LFS. KIR mismatching was associated with a higher incidence of relapse, 47% (34-58) and 32% (24-41), respectively (P=0.05). Multivariate analysis identified active disease at transplantation (HR 6.38, P<0.001), KIR mismatching (HR 1.97, P=0.03), female donors (HR 0.58, P=0.03) and reduced-intensity conditioning (HR 1.71, P=0.05) as factors associated with 2-year relapse. KIR mismatching was not associated with NRM, acute or chronic GVHD.Conclusions: Haplo-identical transplant with PTCy and PBSC graft is associated with favorable outcome in patients with acute leukemia. KIR ligand mismatching may be associated with increased relapse rate and worse survival in these patients. Donors with KIR mismatching should be avoided when possible in the PBSC haplo-identical setting. [Display omitted] DisclosuresCiceri:GSK: Other: B-thalassemia gene therapy was developed by Fondazione Telethon and Ospedale San Raffaele and has been inlicenced by GSK that provides funding for the clinical trial, Research Funding. Mohty:Sanofi: Honoraria, Speakers Bureau.

Frontispiece: Pnictogen‐Functionalised C1 Ligands: MC‐ARn (n=0, 1, 2, 3)

Phosphorus, etymologically “the bringer of light,” and the other heavy pnictogens are represented by lit matches (loosely) coloured by their respective flame tests. Read more about recent developments in the chemistry of pnictogen-functionalised C1 ligands, LnMCARm (A=P, As, Sb, Bi; m=0, 1, 2, 3) in the Review by A. Hill et al. on page 5322.

Pnictogen-Functionalised C1 Ligands: MC-ARn (n=0, 1, 2, 3).

The chemistry of transition metal carbynes, Ln M≡CR, has historically been dominated by species bearing hydrocarbyl or amino 'R' substituents, with other elements appearing only sporadically. In recent years, carbynes and related 'C1 ' species bearing other main-group substituents, particularly heavier elements of the p-block, have begun to emerge. This review details the chemistry of heavier pnictogen-functionalised C1 ligands, MCARn (A=P, As, Sb, Bi; n=0-3), including their syntheses, properties and reactivities, and how these are distinguished from more traditional carbyne complexes. Recent developments in the closely related phospha-isonitrile Ln M(CPR), cya-phosphide and cya-arside ligands, Ln M(C≡A) (A=P, As), are also discussed.

Challenging Metathesis Catalysts with Nucleophiles and Brønsted Base: Examining the Stability of State-of-the-Art Ruthenium Carbene Catalysts to Attack by Amines.

Critical to advancing the uptake of olefin metathesis in leading contexts, including pharmaceutical manufacturing, is identification of highly active catalysts that resist decomposition. Amines constitute an aggressive challenge to ruthenium metathesis catalysts. Examined here is the impact of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), morpholine, n-butylamine, and triethylamine on Ru metathesis catalysts that represent the current state of the art, including cyclic alkyl amino carbene (CAAC) and N-heterocyclic carbene (NHC) complexes. Accordingly, the amine-tolerance of the nitro-Grela catalyst RuCl2(H2IMes)(=CHAr) (nG; Ar = C6H4-2-OiPr-5-NO2) is compared with that of its CAAC analogues nGC1 and nGC2, and the Hoveyda-class catalyst RuCl2(C2)(=CHAr′) HC2 (Ar′ = C6H4-2-OiPr). In C1, the carbene carbon is flanked by an N-2,6-Et2C6H3 group and a CMePh quaternary carbon; in C2, by an N-2-iPr-6-MeC6H3 group and a CMe2 quaternary carbon. The impact of 1 equiv amine per Ru on turnover numbers (TONs) in ring-closing metathesis of diethyl diallylmalonate was assessed at 9 ppm Ru, at RT and 70 °C. The deleterious impact of amines followed the trend NEt3 ∼ NH2nBu ≪ DBU ∼ morpholine. Morpholine is shown to decompose nGC1 by nucleophilic abstraction of the methylidene ligand; DBU, by proton abstraction from the metallacyclobutane. Decomposition was minimized at 70 °C, at which nGC1 enabled TONs of ca. 60 000 even in the presence of morpholine or DBU, vs ca. 80 000 in the absence of base. Unexpectedly, H2IMes catalyst nG delivered 70–90% of the performance of nGC1 at high temperatures, and underwent decomposition by Brønsted base at a similar rate. Density functional theory (DFT) analysis shows that this similarity is due to comparable net electron donation by the H2IMes and C1 ligands. Catalysts bearing the smaller C2 ligand were comparatively insensitive to amines, owing to rapid, preferential bimolecular decomposition.

SOX2 is a positive regulator of osteoclast differentiation

Elucidating the mechanism underlying osteoclast differentiation is important to improve our understanding of the pathophysiologies related to skeletal diseases and osteolytic metastasis in cancer. Sex-determining region Y-box containing gene 2 (SOX2), a stemness marker, is known to affect osteoblast differentiation and cancer metastasis. However, its role in osteoclastogenesis has not been investigated to date. Here, we report that SOX2 protein and mRNA expression was upregulated during osteoclast differentiation. The overexpression or knockdown of SOX2 in osteoclast precursor cells enhanced or suppressed, respectively, receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclast differentiation and migration, and nuclear factor of activated T-cell c1 (NFATc1) and factor-associated suicide ligand (FASL) expression. In addition, epidermal growth factor receptor (EGFR) and extracellular signal-regulated kinase (ERK) activation were regulated by SOX2 expression; both EGFR and ERK inhibitors abrogated the SOX2 overexpression-induced increase in osteoclast differentiation and NFATc1 expression under RANKL stimulation. Overall, these results suggest SOX2 as a positive regulatory factor during osteoclast differentiation partly through the EGFR and ERK signaling pathways, highlighting a new potential target for restoring abnormal osteoclast activation.

Steric Tuning of Sulfinamide/Sulfoxides as Chiral Ligands with C1, Pseudo-meso, and Pseudo-C2 Symmetries: Application in Rhodium(I)-Mediated Arylation.

A new family of sulfinamide/sulfoxide derivatives was synthesized as chiral bidentate ligands by stereoselective additions of methylsulfinyl carbanions to N-tert-butylsulfinylimines. The new ligands, with C1, pseudo-meso, and pseudo-C2 symmetries, were successfully assayed in Rh-catalyzed additions of arylboronic acids to activated ketones. The sterically dissymmetric C1 ligand (RS,SC,RS)-N-[1-(phenylsulfinyl)-3-methylbut-2-yl] tert-butylsulfinamide turned out to be the optimal one, allowing the 1,4-additions of diverse arylboronic acids, on different α,β-unsaturated cyclic ketones with high chemical yields and enantioselectivities up to >99% ee.

Natural Killer Cells Offer Differential Protection From Leukemia in Chinese Southern Han.

Interactions of human natural killer (NK) cell inhibitory receptors with polymorphic HLA-A, -B and -C molecules educate NK cells for immune surveillance against tumor cells. The KIR A haplotype encodes a distinctive set of HLA-specific NK cell inhibiting receptors having strong influence on immunity. We observed higher frequency of KIR A homozygosity among 745 healthy Chinese Southern Han than 836 adult patients representing three types of leukemia: ALL (OR = 0.68, 95% CI = 0.52–0.89, p = 0.004), AML (OR = 0.76, 95% CI = 0.59–0.98, p = 0.034), and CML (OR = 0.72 95% CI = 0.51–1.0, ns). We observed the same trend for NHL (OR = 0.47 95% CI = 0.26–0.88 p = 0.017). For ALL, the protective effect of the KIR AA genotype was greater in the presence of KIR ligands C1 (Pc = 0.01) and Bw4 (Pc = 0.001), which are tightly linked in East Asians. By contrast, the C2 ligand strengthened protection from CML (Pc = 0.004). NK cells isolated from KIR AA individuals were significantly more cytotoxic toward leukemic cells than those from other KIR genotypes (p < 0.0001). These data suggest KIR allotypes encoded by East Asian KIR A haplotypes are strongly inhibitory, arming NK cells to respond to leukemogenic cells having altered HLA expression. Thus, the study of populations with distinct KIR and HLA distributions enlightens understanding of immune mechanisms that significantly impact leukemia pathogenesis.

The relation between activator and inhibitor killer-cell immunoglobulin-like receptors and hepatotoxicity in oncological treatment.

The molecular interactions between killer-cell immunoglobulin-like receptors (KIRs) and their related HLA class I ligands play a central role in regulating the responses of natural killer (NK) cells. Our study aim was to determine the role played by KIR genes and their HLA ligands in the genetic predisposition for the development of hepatotoxicity in children treated with chemotherapy for an oncological process. The study group was composed of 22 children with cancer, being treated with chemotherapy at the Unit of Pediatric Oncology of the Maternity Hospital Virgen de las Nieves (Granada, Spain) and presenting signs of drug-induced liver injury (DILI). Twenty-four children receiving similar treatment but presenting no signs of DILI were selected as a control group. The children with the KIR K2DS2 were four times more likely to have hepatotoxicity (OR=4.08, P=0.034, 95% CI: 1.1-15). The patients with 2DS2 and the C1 ligand were ten times more likely to undergo an episode of hepatotoxicity (P=0.007). KIRs may be risk factors for susceptibility to hepatotoxicity following chemotherapy.

PB1741 KIR‐LIGAND MISMATCH IS NOT PREDICTIVE FOR LEUKEMIA‐FREE SURVIVAL IN PATIENTS WITH FAVORABLE RISK AML AFTER AUTOLOGOUS STEM CELL TRANSPLANTATION.

Background:Evidence suggests that Natural Killer (NK) Cells may play a role in the prevention of relapse of Acute Myeloid Leukemia after allogeneic stem cell transplantation (alloSCT). In a specific condition being HLA mismatched transplants, NK cells may get activated because subsets of donor NK cells miss inhibitory HLA alleles on the patient's cells. This is called. KIR‐ligand mismatch, were subsets of donor NK cells get activated when the patient's HLA alleles are not fitting to one or two of the inhibitory KIRs expressed on the donor cells (Ruggeri, Science 2002). The prerequisite for effective KIR‐ligand mismatch seems to be extensive AGVHD prevention by CD34‐selection of the stem cell graft or intense immunosuppressive conditioning including ATG. In HLA‐matched sibling alloSCT the same beneficial effect of KIR‐ligand mismatch was observed when intense T cell depletion of the graft had been applied (Hsu et al., Blood 2005). It was shown that early post T‐cell depleted alloSCT normally hyporesponsive NK cells expressing KIR for non‐self HLA temporarily displayed full functional capacity (Hsu, Blood 2009).Aims:We hypothesized that a beneficial effect of KIR‐ligand mismatch effect may be present in autologous SCT (autoHCT) in AML, where GVHD obviously is impossible. This would imply that developing NK cells harboring one or two inhibitory KIR receptors (iKIRs) for which no fitting HLA‐allele is present might temporarily get activated in those patients that do not bear all three relevant groups of HLA‐alleles (Bw4, C1 and C2) for which inhibitory KIRs are almost always there (presence of KIR2DL2/3 (fitting C1), KIR2DL1 (fitting C2) and KIR3DL1 (fitting Bw4) is 100%, 92.7% and 92.1% respectively, Hsu, Blood 2005). Approximately 30% of the population bears all three ligands for these three iKIRs and are not susceptible for KIR‐ligand mismatch.Methods:We typed all autologous transplanted AML patients in our center with genetic favorable risk factors (according to ELN 2017) and in first complete remission for HLA Bw4, C1 and C2. 2‐year leukemia‐free survival (LFS) of those patients not susceptible for KIR‐ligand mismatch was compared with LFS of those being susceptible. It was expected that 33% of the auto‐transplanted patients would relapse (Vellenga, Blood 2011). Assuming a meaningful higher 2‐year LFS of 87% for patients missing at least ligand (i.e. 15% higher than observed for the whole population), 2‐year LFS in those not missing a KIR ligand would have been 32% (3x 72 = 216; 216 – (2x 87) = 216 – 174 = 32). To demonstrate this difference 9 patients per group are needed. However, because of the unequal distribution of the two groups (“missing no KIR ligand” vs. “missing at least 1i KIR ligand”) to ensure that the “not missing a KIR ligand group” contains 9 patients at least 3x9=27 patients are needed.Results:We identified 39 favorable risk auto‐transplanted AML patients. Twelve had all HLA ligands for all three iKIRs present, and 27 lacked at least one ligand. 2‐year LFS was 83% and 83% respectively. For those 11 that missed HLA C1 ligands (for which all individuals have a ligand (i.e. KIR2DL2/3) 2‐year LFS was 81%.Summary/Conclusion:2‐year LFS is very high after autoHCT in first complete remission in favorable risk AML and KIR‐ligand mismatch is not relevant.image