Effector Target Research Articles

Experimental Study of the In Vitro and In Vivo Functional Activity of NKG2D Chimeric Antigen Receptor

Aim. To study antitumor cytotoxic effect of CAR-T NKG2D and CAR-T anti-CD19 in vitro and in vivo in order to compare antitumor activity of chimeric antigen receptors (CAR) with different structural and functional properties. Materials & Methods. CAR constructions were produced by molecular cloning. CAR-T cell populations were obtained by transduction of healthy donor T-lymphocytes with recombinant lentiviral particles coding CAR NKG2D or CD19 target antigen CAR sequences. CAR-T cell proportion was assessed by FusionRed fluorescence and EGFR membrane receptor imaging. Specific in vitro cytotoxic activity of CAR-T effector cells was analyzed by Real-Time Cytotoxicity Assay (RTCA) during co-cultivation with HeLa_CD19 target cell line using xCELLigence. Interferon-Y (IFN-y) synthesis in vitro and in vivo along with the degree of cytotoxic effect were analyzed by immunoassay of culture medium of co-cultivated effector cells and target cells as well as isolated auto-plasma from the peripheral blood of mice. To assess the in vivo functional activity, CAR-T cell populations were infused into immunodeficient NSG-SGM3 mice (10 000 000 cells/mouse) 12 days after HeLa_CD19 cell injection and confirmation of engraftment and tumor growth. Upon euthanasia, tumors were removed and fixed in paraffin to prepare histological sections. CAR-T cell tumor infiltration was assessed by CD3 antigen immunohistochemical staining. Results. The highest ligand (molecules MICA, ULBP1/2/3/4/5/6) expression levels were detected in HeLa cell line. The obtained NKG2D CAR-T cells showed a considerable cytotoxic activity against HeLa_CD19 target line (cell index [CI] = 1.27), which was, however, twice as low as that of CAR-T anti-CD19 (CI = 0.60) (p = 0.0038). IFN-y level during co-cultivation of CAR-T anti-CD19 with HeLa_CD19 at the ratio of Е/Т = 1:1 was 64,852 pcg/mL, which was 3.5 times higher than IFN-y level during co-cultivation of CAR-T NKG2D with HeLa_CD19 (18,635 pcg/mL) (p = 0.0360). The degree of tumor infiltration by CAR-T anti-CD19 cells was higher than that by CAR-T NKG2D. The absence of NKG2D proliferating CAR-T cells in mice peripheral blood confirms their low persistence. IFN-y concentration in mice auto-plasma was 11.89 pcg/mL after CAR-T anti-CD19 infusion and 0.57 pcg/mL after CAR-T NKG2D infusion (p = 0.0079). The mean weight of tumor xenografts in experimental groups 10 days after CAR-T anti-CD19 injection was 0.72 g (p = 0.0142), after Т-lymphocyte and NKG2D CAR-T cell infusions it was 2.12 g and 1.2 g, respectively. Conclusion. CAR-T anti-CD19 cells are characterized by more pronounced cytotoxic effect under both in vitro and in vivo experimental conditions compared with CAR-T NKG2D cells. The degree of CAR-T anti-CD19 proliferation and their infiltration in mice xenograft models is considerably higher than the levels reached with NKG2D CAR-T cell injections. A single CAR-T NKG2D injection results only in short-term tumor reduction.

A rice protein interaction network reveals high centrality nodes and candidate pathogen effector targets

Network science identifies key players in diverse biological systems including host-pathogen interactions. We demonstrated a scale-free network property for a comprehensive rice protein–protein interactome (RicePPInets) that exhibits nodes with increased centrality indices. While weighted k-shell decomposition was shown efficacious to predict pathogen effector targets in Arabidopsis, we improved its computational code for a broader implementation on large-scale networks including RicePPInets. We determined that nodes residing within the internal layers of RicePPInets are poised to be the most influential, central, and effective information spreaders. To identify central players and modules through network topology analyses, we integrated RicePPInets and co-expression networks representing susceptible and resistant responses to strains of the bacterial pathogens Xanthomonas oryzae pv. oryzae and X. oryzae pv. oryzicola (Xoc) and generated a RIce-Xanthomonas INteractome (RIXIN). This revealed that previously identified candidate targets of pathogen transcription activator-like (TAL) effectors are enriched in nodes with enhanced connectivity, bottlenecks, and information spreaders that are located in the inner layers of the network, and these nodes are involved in several important biological processes. Overall, our integrative multi-omics network-based platform provides a potentially useful approach to prioritizing candidate pathogen effector targets for functional validation, suggesting that this computational framework can be broadly translatable to other complex pathosystems.

A Novel Antibacterial Component and the Mechanisms of an Amaranthus tricolor Leaf Ethyl Acetate Extract against Acidovorax avenae subsp. citrulli.

The aim of the present investigation was to determine the active ingredients in Amaranthus tricolor L. leaves and develop a biological pesticide. Organic solvent extraction, column chromatography, liquid chromatography, ODS-C18 reverse elution, Sephadex LH-20 gel filtration, H spectrum, and C spectrum were used to isolate the pure product for an assessment of the agricultural activity and bacteriostatic mechanisms. The results showed that the activity of the crude extract following carbon powder filtration was 1.63-fold that of the non-filtered extract. Further isolation was performed to obtain two pure products, namely, hydroxybenzoic acid (HBA) and benzo[b]furan-2-carboxaldehyde (BFC), and their molecular formulas and molecular weights were C7H6O3 and 138.12, and C9H6O2 and 146.12, respectively. Our study is the first to determine that HBA has bacteriostatic activity (MIC 125 μg/mL) and is also the first to isolate BFC from A. tricolor. The ultrastructure observation results showed that HBA caused the bacteria to become shriveled, distorted, and deformed, as well as exhibit uneven surfaces. After HBA treatment, 70 differentially expressed metabolites were detected in the bacteria, of which 9 were downregulated and 61 were upregulated. The differentially expressed metabolites were mainly strigolactones, organic acids and derivatives, fatty acids, benzene and substituted benzene derivatives, amino acids and associated metabolites, and alcohols and amines. Among all of the downregulated differentially expressed metabolites, MEDP1280 was the most critical, as it participates in many physiological and biochemical processes. The enrichment analysis showed that the differentially expressed metabolites mainly participate in tyrosine metabolism, biosynthesis of amino acids, cysteine and methionine metabolism, and arginine and proline metabolism. Additionally, HBA was found to disrupt cell membrane permeability and integrity, causing the leakage of substances and apoptosis. The physiological and biochemical test results showed that HBA could increase the pyruvate levels in bacteria but could decrease the activities of respiratory enzymes (malate dehydrogenase (MDH) and NADH oxidase) and antioxidant enzymes (superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX)). Inverse molecular docking was used to study the binding between HBA and respiratory and antioxidant enzymes. The results showed that HBA could bind to MDH, NADH oxidase, SOD, and GSH-PX, suggesting that these enzymes may be the effector targets of HBA. Conclusion: The optimal active ingredient in A. tricolor that can inhibit Acidovorax avenae subsp. citrulli was identified as HBA. HBA mainly disrupts the cell membrane, damages the metabolic system, and inhibits respiration and antioxidant enzyme activity to control bacterial growth. These results provide a reference for the further development of biological pesticides.

Rapid kinetics of calcium dissociation from plant calmodulin and calmodulin-like proteins and effect of target peptides

Calcium (Ca2+) signaling represents a universal information code in plants, playing crucial roles spanning developmental processes to stress responses. Ca2+ signals are decoded into defined plant adaptive responses by different Ca2+ sensing proteins, including calmodulin (CaM) and calmodulin-like (CML) proteins. Although major advances have been achieved in describing how these Ca2+ decoding proteins interact and regulate downstream target effectors, the molecular details of these processes remain largely unknown. Herein, the kinetics of Ca2+ dissociation from a conserved CaM and two CML isoforms from A. thaliana has been studied by fluorescence stopped-flow spectroscopy. Kinetic data were obtained for the isolated Ca2+-bound proteins as well as for the proteins complexed with different target peptides. Moreover, the lobe specific interactions between the Ca2+ sensing proteins and their targets were characterized by using a panel of protein mutants deficient in Ca2+ binding at the N-lobe or C-lobe. Results were analyzed and discussed in the context of the Ca2+-decoding and Ca2+-controlled target binding mechanisms in plants.

Depletion of central memory CD8+ T cells might impede the antitumor therapeutic effect of Mogamulizumab

Regulatory T (Treg) cells are important negative regulators of immune homeostasis, but in cancers they tone down the anti-tumor immune response. They are distinguished by high expression levels of the chemokine receptor CCR4, hence their targeting by the anti-CCR4 monoclonal antibody mogamulizumab holds therapeutic promise. Here we show that despite a significant reduction in peripheral effector Treg cells, clinical responses are minimal in a cohort of patients with advanced CCR4-negative solid cancer in a phase Ib study (NCT01929486). Comprehensive immune-monitoring reveals that the abundance of CCR4-expressing central memory CD8+ T cells that are known to play roles in the antitumor immune response is reduced. In long survivors, characterised by lower CCR4 expression in their central memory CD8+ T cells possessed and/or NK cells with an exhausted phenotype, cell numbers are eventually maintained. Our study thus shows that mogamulizumab doses that are currently administered to patients in clinical studies may not differentiate between targeting effector Treg cells and central memory CD8+ T cells, and dosage refinement might be necessary to avoid depletion of effector components during immune therapy.

Oomycete intracellular effectors: specialised weapons targeting strategic plant processes.

Oomycete phytopathogens have adapted to colonise plants using effectors as their molecular weapons. Intracellular effectors, mostly proteins but also small ribonucleic acids, are delivered by the pathogens into the host cell cytoplasm where they interfere with normal plant physiology. The diverse host processes emerging as 'victims' of these 'specialised bullets' include gene transcription and RNA-mediated silencing, cell death, protein stability, protein secretion and autophagy. Some effector targets are directly involved in defence execution, while others participate in fundamental metabolisms whose alteration collaterally affects defences. Other effector targets are susceptibility factors (SFs), that is host components that make plants vulnerable to pathogens. SFs are mostly negative regulators of immunity, but some seem necessary to sustain or promote pathogen colonisation.

FOXM1-mediated activation of phospholipase D1 promotes lipid droplet accumulation and reduces ROS to support paclitaxel resistance in metastatic cancer cells

Chemoresistance is a major challenge for the treatment of cancer with metastasis. We investigated the mechanisms of lipid metabolites involved in drug resistance. Here, metastatic cancer cells isolated from mouse models were resistant to paclitaxel treatment in vitro and in vivo when compared with parental cancer cells. FOXM1, an oncogenic transcriptional factor, was highly expressed in metastatic cancer cells, and overexpression of FOXM1 conferred parental cancer cells resistance to paclitaxel. Lipidomic analysis showed that FOXM1 increased unsaturated triglyceride (TG) and phosphatidylcholine (PC) abundance, which are the main components of lipid droplet (LD). Inhibition of LD formation sensitized cells to paclitaxel. Mechanistically, the enzyme phospholipase D1 (PLD1) was identified as a potential effector target of FOXM1. PLD1 promoted LD accumulation, which reduced the level of reactive oxygen species (ROS) and maintained endoplasmic reticulum (ER) homeostasis in resistant cells with the treatment of paclitaxel. Moreover, inhibition of PLD1 reversed FOXM1-conferred paclitaxel resistance in vitro and in vivo. This study, for the first time, reveals the role of FOXM1-mediated PLD1 in LD accumulation and paclitaxel resistance. Targeting PLD1 or LD formation may help reverse chemoresistance in metastatic cancer cells. Generally, our results identified FOXM1 as a driver of paclitaxel resistance via activation of PLD1 to promote of LD accumulation, which contributes to the maintenace of ER homeostasis when metastatic cancer cells are confronted with ROS induced by paclitaxel.

Abstract PO-089: Identification of a LAMC2-regulated network featuring targetable effectors for dual therapies in pancreatic cancer

Abstract Background: Pancreatic cancer stands as one of the deadliest tumors, in part due to the limited efficacy of currently existing therapies. Pancreatic cancer is characterized at the genomic level by the almost universal presence of KRAS mutations. Phenotypically, it features an incipient desmoplastic stroma with a protein component formed by collagens, fibronectin and laminins. A member of the laminin family, LAMININ γ2 or LAMC2, was previously identified by our group as part of a cross-tumors KRAS signature whose high expression was a marker of poor survival in PDAC patients. While a role for LAMC2 in migration and invasion has been previously described, little is known about a potential function in cell proliferation and viability. Moreover, LAMC2 inhibition has been shown to enhance the activity of conventional chemotherapeutic agents. However, whether its abrogation can increase the effect of targeted therapies is yet to be defined. Finally, the direct relationship between LAMC2 and the KRAS oncogene network is yet to be defined. Methods: A meta-analysis of several human PDAC data sets and survival analysis of the TCGA data were performed to query the expression levels and prognosis significance of LAMC2. Human and mouse PDAC cell lines as well as a mouse model of PDAC (KrasLSLG12D, Tp53f/f, Ptf1aCre) were used to assess LAMC2 expression. In vitro (2D and 3D organoids) and in vivo models derived from human and mouse PDAC cell lines or primary tumors were used to define the functional role of LAMC2 in PDAC. Cellular and molecular analysis were deployed to dissect the mechanism of action of LAMC2 in PDAC. A dual pharmacological combination based on LAMC2-regulated effectors was also tested in human and mouse pancreatic cancer models. Results: At the clinical level, we observed that LAMC2 is overexpressed in human PDAC patients with regard to normal tissue. The overexpression of LAMC2 was recapitulated in human and mouse cell lines. Genetic depletion of LAMC2 had an adverse effect in 2D proliferation, clonogenic efficiency, 3D organoid growth, and PDAC-based xenograft/allograft tumor development. This deleterious effect was driven by an induction in apoptosis and a decrease in S phase consistent across species. Mechanistically, LAMC2 was linked to the KRAS pathway via transcriptional regulation of the transcription factor FOSL1/AP1, which was also a member of the cross-tumors signature. Furthermore, LAMC2 controlled a gene signature that overlaps with KRAS- and FOSL1-regulated gene signatures, which was also highly expressed in various pancreatic cancer data sets, and includes the targetable kinase AXL. Lastly, concomitant pharmacological inhibition of AXL and the FOSL1 upstream regulator MEK1/2 displayed a more adverse effect on human and pancreatic pancreatic cancer than each single drug alone. Conclusion: These data suggest that LAMC2 is a molecular target tightly linked to KRAS oncogene signaling that regulates downstream effectors amenable to the development of combination therapies. Citation Format: Shruthi Narayanan, Oihane Erice, Iker Feliu, Caterina Vicentini, Rodrigo Entrialgo-Cadierno, Karmele Valencia, Elisabet Guruceaga, Purvesh Khatri, Vicenzo Corbo, Silvestre Vicent Cambra, Mariano Ponz-Sarvise. Identification of a LAMC2-regulated network featuring targetable effectors for dual therapies in pancreatic cancer [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr PO-089.

A Novel Method for Highly Efficient Ex Vivo Expansion and Genetic Engineering of Human Natural Killer Cells for Cancer Therapy

Cancer immunotherapy with adoptive transfer of human leukocyte antigen-mismatched, CD19-targetd chimeric antigen receptor (CAR)-transduced natural killer (NK) cells has attracted attention because of its efficacy and safety when infused in patients with refractory and relapsed B-cell lymphomas. However, generating clinical doses of CAR-NK cells is still a challenge. The methods for ex vivo expansion and genetic modification of primary human NK cells usually rely on the use of irradiated feeder cell lines, which has been restrictive due to high costs, scale-up difficulties, and licensing restrictions. Hence, novel strategies that do not require feeder cells will be beneficial in standardizing these types of cell therapies. In this study, we show the effectiveness of a novel feeder-free culture system in expanding NK cells ex vivo and generating CAR-NK cells.Unsorted peripheral blood mononuclear cells (PBMCs) collected from healthy donors were cultured with a reagent containing dissolvable microspheres that are conjugated with anti-CD2/NKp46 antibodies (Cloudz TM Human NK Cell Expansion Kit) and a combination of multiple cytokines, including interleukin (IL)-2, IL-12, IL-18, and IL-21 in medium supplemented with 10% fetal bovine serum. The activated NK cells were transduced using the RD114-pseudotyped retrovirus vector.To test whether the reagent promoted ex vivo NK cell expansion, we cultured PBMCs from 13 donors. The percentage of NK (CD56 + CD3 -) cells of initially isolated PBMCs was 15.3±7.5%. In the presence of multiple cytokine combinations, NK cell purity gradually increased and reached 91.6±7.6% by day 21. The NK cells expanded to 75.6±59.2-fold at day 10, 334±217-fold at day 14 and 1,542±913-fold at day 21. The expanded NK cells degranulated and produced intracellular cytokines upon exposure to K562 myeloid leukemia cells. The NK cells efficiently killed myeloid leukemia cells, such as K562, THP1, and KG1. The expression pattern of killer cell immunoglobulin-like receptors on NK cells remained unchanged. The expression of activating NK cell receptors, including NKp30 and NKp44, increased after 21 days of culture.Thereafter, a gene transfer to the primary human NK cells was conducted. We tested transduction efficiency and yields of modified cells on 7 days after the procedure by empty-vector transduction into NK cells expanded ex vivo for 3, 6, and 10 days (n=3, each). The results were presented as means ± standard deviation; 55.6±11.6%, 61.6±14.1%, and 73.6%±6.2% for GFP positivity in NK cells and 5.7±1.5 folds, 56.4±42.2 folds, and 12.7±5.8 folds for yields of modified cells. We selected the condition in which the transduction was carried out using NK cells expanded ex vivo for 6 days, although the differences were not statistically significant. Next, anti-CD19 CAR with a 4-1BB costimulatory and CD3z domain was transduced into NK cells. We confirmed high transduction efficiency (59.8% ±20.5%, n=3) and high CAR protein expression on the cell surface, while NK cells maintained their purity and minimal T cell outgrowth was observed. CAR-NK cells maintained their proliferative status and further expanded 15.2±6.4-fold after 7 days of the procedure.To determine whether the generated anti-CD19 CAR-NK cells had a specific effect on B cell malignancies, a CD107a mobilization assay, intracellular cytokine assay, and a flow cytometry-based cytotoxicity assay was employed. We found that CAR transduction could render NK cells to generate specific and powerful responses against CD19-positive, NK-resistant leukemia and lymphoma cell lines, such as BCR-ABL-positive acute lymphoblastic leukemia (ALL) OP-1, Burkitt lymphoma Raji, and KMT2A-rearranged ALL RS4;11, at various effector: target (ET) ratios. For example, in a 4 hour -assay, the cytotoxic effects of anti-CD19 CAR-NK cells showed 86.9±0.2% cytotoxicity against OP-1, while mock NK cells showed 17.4±2.9% cytotoxicity (ET ratio 1:1).In conclusion, this study revealed highly efficient functions of the novel feeder-free culture system, including highly efficient ex vivo expansion of primary human NK cells and generation of genetically modified NK cells for cancer immunotherapy. In future studies, we will investigate large-scale cultures using specialized flasks and GMP-grade reagents for clinical translation and the in vivo activities of the cell products in mouse xenograft models. DisclosuresImai: Juno Therapeutics: Patents & Royalties: chimeric receptor with 4-1BB signaling domain.

CSF3R T618I Collaborates with RUNX1-RUNX1T1 to Expand Human Haematopoietic Stem and Progenitor Cells

The cytokine receptor colony stimulating factor 3 (CSF3R) controls differentiation, proliferation and function of granulocytes as well as mobilization of hematopoietic stem cells upon activation via G-CSF. An oncogenic role of CSF3R mutations has been mainly described in chronic neutrophilic leukemia (CNL) and, more rarely, in atypical chronic myeloid leukemia and pediatric acute myeloid leukemia (AML) (Maxson et al., 2013, N Engl J Med; Maxson et al.,2016, Blood).CSF3R mutations are classified in two distinct categories: truncating mutations and proximal-membrane domain mutations. While truncating mutations lead to a higher sensitivity toward the ligand, the more common proximal-membrane mutations are ligand-independent in activating downstream signaling.Recently, we found CSF3R recurrently mutated in 5% (13/292) of patients with adult core-binding factor (CBF) leukemia (Opatz et al., 2020, Leukemia). Both CBF leukemia subgroups, characterized by either an inversion of chromosome 16 (inv(16)) or translocation t(8;21), were affected. The most prevalent mutation hotspot was T618 in the t(8;21) subgroup, localizing to the proximal-membrane region, recurrently affected also in CNL.We set out to study the role of CSF3R mutations in AML t(8;21). Using CD34+ hematopoietic stem cells from adult healthy donors, we observed that co-expression of the CSF3R mutant T618I (CSF3R T618I) but not CSF3R wildtype (WT)together with the t(8;21) related RUNX1-RUNX1T1 fusion led to a competitive outgrowth of cells (Figure 1A,B). In contrast, over-expression of either CSF3R WT or CSF3R T618Ialone did not lead to a competitive advantage. Furthermore, in a culture composed of >95% RUNX1-RUNX1T1 positive expanded cells, super-infection with the retroviral CSF3R T618I construct led to complete outgrowth of double positive cells over a period of 60 days. These data suggest an oncogenic cooperation between RUNX1-RUNX1T1 and CSF3R T618I. Comparing the cytomorphology of RUNX1-RUNX1T1 single positive cells and RUNX1-RUNX1T1/CSF3R T618I double positive cells, the single positive cells were heterogeneous with a mixture of mature and immature cells (Figure 1C), whereas double positive cells remained mostly undifferentiated, featuring a homogeneous blast-like morphology (Figure 1D). In accordance with these findings, limiting and serial dilution experiments clearly showed an increased self-renewal potential for double oncogene expressing cells compared to cells expressing RUNX1-RUNX1T1 only. This further supports a transforming potential of CSF3R T618I in combination with RUNX1-RUNX1T1.RNA sequencing of outgrown double oncogene expressing cells revealed upregulation of distinct pathways related to myeloid differentiation, in particular neutrophil cell activation and migration. In addition, we found GLI2 as potential downstream effector and putative pharmacological target in AML t(8;21) with CSF3R T618I (Figure 1E). GLI2 expression is a negative prognostic marker in AML, associated with significantly shorter event free and overall survival (Wellbrock et al., 2015, Clin Cancer Res). Acting in the hedgehog-signaling pathway, GLI2 is not expressed in healthy adult tissues. Of note, patient data and mouse models support a specific collaboration of upregulated GLI2 and FLT3-ITD in AML (Wellbrock et al., 2015, Clin Cancer Res; Lim et al., 2015, Sci Transl Med).Conducting further experiments in the granulocyte-macrophage colony stimulating factor (GM-CSF) dependent t(8;21)-positive cell line SKNO-1, we observed cytokine independent growth in the presence of CSF3R T618I but not CSF3R WT. GM-CSF withdrawal of SKNO-1 native cells, vector control or CSF3R WTexpressing cells led to cell cycle arrest that could be overcome by expression of CSF3R T618I.Subsequently, we investigated pharmacological counteraction of CSF3R T618I through inhibition of putative effectors. CSF3R T618I expressing SKNO-1 cells were significantly more sensitive towards treatment with the GLI inhibitor GANT61, as compared to vector or CSF3R WT controls (Figure 1F).Taken together, our results suggest a specific oncogenic collaboration between RUNX1-RUNX1T1 and CSF3R T618I with potential therapeutic implications. [Display omitted] DisclosuresRedondo Monte: Minaris Regenerative Medicine: Current Employment. Greif: AstraZeneca: Honoraria.

Bispecific Vγ9Vδ2-T and Type 1 NKT Cell Engager Lava-051 As First-in-Class Clinical Candidate to Target CD1d Expressing CLL, MM and AML

Bispecific Vγ9Vδ2-T and Type 1 NKT Cell Engager Lava-051 As First-in-Class Clinical Candidate to Target CD1d Expressing CLL, MM and AML

Piggybac Transposon Mediated CD19 CAR-T Cells Derived from CD45RA-Positive PBMCs Possess Potent and Sustained Antileukemic Function

Background: The quality of chimeric antigen receptor (CAR)-T cell products, including the expression of memory and exhaustion markers, has been shown to influence their long-term functionality. We previously demonstrated that piggyBac (PB) transposon-mediated CD19 CAR-T cells exhibit memory-rich phenotype that is characterized by a high proportion of CD45RA+/CCR7+ T cell fraction. To further investigate the favorable phenotype of PB-CD19 CAR-T cells, we generated PB-CD19 CAR-T cells from CD45RA+ and CD45RA− peripheral blood mononuclear cells (PBMCs) (RA+ CAR and RA− CAR, respectively), and compared their phenotype and antitumor function.Methods: CD45RA+ and CD45RA− PBMCs were isolated by magnetic selection from whole PBMCs, then the CD19-CAR transgene was transduced into these cells using the PB transposon system, as described previously. Transduction efficiency of CD19 CAR transgene was determined 24 hours by flow cytometry after transduction. The phenotype of CD19 CAR-T was evaluated by flow cytometry on day 14. High throughput RNA sequencing was performed to see the T cell activation/exhaustion profile upon antigen stimulation. Sequential killing assays were performed by adding fresh tumor cells into CAR-T cells co-cultured with tumor cells every three days by restoring an effector target ratio of 1:1. To see the durable antitumor efficacy in vivo, we performed in vivo stress test, in which CAR T-cells dosage was lowered to the functional limits, so that these CAR-T cells should be maintained and expanded in vivo, to achieve the antitumor efficacy. We injected 5 x 10 5 of firefly luciferase-labeled CD19+ tumor cells (REH) into NSG mice via tail vein, then these mice were treated with 1 x 10 5 of CD19 RA+ CAR-T, RA− CAR-T, or control CAR-T cells, respectively, at day 6 after the tumor injection.Results: RA+ CAR T cells demonstrated better transient transduction efficiency 24 h after transduction (RA+ CAR-T: 77.5 ± 9.8% vs RA− CAR-T: 39.7 ± 3.8%), and superior expansion capacity after 14 days of culture than RA− CAR-T cells (RA+ CAR-T: 32.5 ± 9.3-fold vs RA− CAR-T: 11.1 ± 5.4-fold). RA+ CAR-T cells exhibited dominant CD8 expression (RA+ CAR-T: 84.0 ± 3.4% vs RA− CAR-T: 34.1 ± 10.6%), less expression of exhaustion marker PD-1 (RA+ CAR-T: 3.1 ± 2.5% vs RA− CAR-T: 19.2 ± 6.4%) and T cell senescence marker CD57 (RA+ CAR-T: 6.8 ± 3.6% vs RA− CAR-T: 20.2 ± 6.9%), and enrichment of naïve/stem cell memory fraction (CAR+/CD45RA+CCR7+ fraction; RA+ CAR-T: 71.9 ± 9.7% vs RA− CAR-T: 8.0 ± 5.3%), which were associated with longevity of CAR-T cells. Transcriptome analysis revealed that RA+ CAR-T cells exhibited the enrichment of naïve/memory phenotype and less expression of canonical exhaustion markers, and these exhaustion profiles even maintained after the antigen stimulation. RA+ CAR-T cells demonstrated sustained killing activity even after multiple tumor rechallenges in vitro, without inducing exhaustion marker expression of PD-1. Although antigen stimulation could increase CAR expression, leading to tonic CAR signaling and exhaustion, in our study, the expression of CAR molecule on the cell surface following antigen stimulation in RA+ CAR was controlled at a relatively lower level that in RA− CAR-T cells. RA+ CAR-T cells achieved prolonged tumor control with expansion of CAR-T cells than RA− CAR-T cells in in vivo stress test (Fig.1A-C). On day15, bone marrow studies in RA+ CAR group exhibited abundant human CD3 positive T cells with less expression of PD-1, and relatively smaller amount of REH cells than RA− CAR group (Fig.1D). Furthermore, in two of long-lived mice in RA+ CAR group, human CD3 positive T cells were expanded even day 50 after treatment as confirmed by sequential bone marrow studies (Fig.1E), which indicated the antigen-induced proliferation and long-term functionality of RA+ CAR-T cells in vivo.Conclusion: Our results suggest that PB-mediated RA+ CAR-T cells exhibit memory-rich phenotype and superior antitumor function, thereby indicating the usefulness of CD45RA+ PBMC as a starting material of PB-CAR-T cells. [Display omitted] DisclosuresYagyu: AGC Inc.: Research Funding. Nagao: AGC Inc.: Current Employment. Kubota: AGC Inc.: Current Employment. Shimizu: AGC Inc.: Current Employment. Nakazawa: AGC Inc.: Research Funding; Toshiba Corporation: Research Funding.

RAS protein activator like 2 promotes the proliferation and migration of pulmonary artery smooth muscle cell through AKT/mammalian target of Rapamycin complex 1 pathway in pulmonary hypertension

ABSTRACT RAS protein activator like 2 (Rasal2) exerts pro-proliferative effect in several types of cells. However, whether Rasal2 is involved in the regulation of pulmonary artery smooth muscle cell (PASMC) remains unclear. In the current study, we explored the role of Rasal2 in proliferation and migration of PASMC during the development of pulmonary arterial hypertension (PAH). We found that the protein level of Rasal2 was increased in both pulmonary arteries of chronic hypoxia-induced pulmonary hypertension (CH-PH) mice and hypoxia-challenged PASMC. Overexpression of Rasal2 caused enhanced proliferation and migration of PASMC after hypoxia exposure. Mechanistically, we found elevated phosphorylation of AKT and two downstream effectors of mammalian target of Rapamycin complex 1 (mTORC1), S6 and 4E-Binding Protein 1 (4EBP1) after Rasal2 overexpression in hypoxia-challenged PASMC. Inactivation of mTORC1 abolished Rasal2-mediated enhancement of proliferation and migration of PASMC. Furthermore, we also demonstrated that AKT might act downstream of Rasal2 to enhance the activity of mTORC1. Once AKT was inactivated by MK-2206 application, overexpression of Rasal2 failed to further increase the phosphorylation level of S6 and 4EBP1. Finally, inhibition of AKT also blocked Rasal2-induced proliferation and migration in hypoxia-challenged PASMC. In conclusion, Rasal2 promotes the proliferation and migration of PASMC during the development of PAH via AKT/mTORC1 pathway.

Expanding RNA target effectors.

Expanding RNA target effectors.

Monocyte Chemotactic Protein-Induced Protein 1 (MCPIP-1): A Key Player of Host Defense and Immune Regulation

Inflammatory response is a host-protective mechanism against tissue injury or infections, but also has the potential to cause extensive immunopathology and tissue damage, as seen in many diseases, such as cardiovascular diseases, neurodegenerative diseases, metabolic syndrome and many other infectious diseases with public health concerns, such as Coronavirus Disease 2019 (COVID-19), if failure to resolve in a timely manner. Recent studies have uncovered a superfamily of endogenous chemical molecules that tend to resolve inflammatory responses and re-establish homeostasis without causing excessive damage to healthy cells and tissues. Among these, the monocyte chemoattractant protein-induced protein (MCPIP) family consisting of four members (MCPIP-1, -2, -3, and -4) has emerged as a group of evolutionarily conserved molecules participating in the resolution of inflammation. The focus of this review highlights the biological functions of MCPIP-1 (also known as Regnase-1), the best-studied member of this family, in the resolution of inflammatory response. As outlined in this review, MCPIP-1 acts on specific signaling pathways, in particular NFκB, to blunt production of inflammatory mediators, while also acts as an endonuclease controlling the stability of mRNA and microRNA (miRNA), leading to the resolution of inflammation, clearance of virus and dead cells, and promotion of tissue regeneration via its pleiotropic effects. Evidence from transgenic and knock-out mouse models revealed an involvement of MCPIP-1 expression in immune functions and in the physiology of the cardiovascular system, indicating that MCPIP-1 is a key endogenous molecule that governs normal resolution of acute inflammation and infection. In this review, we also discuss the current evidence underlying the roles of other members of the MCPIP family in the regulation of inflammatory processes. Further understanding of the proteins from this family will provide new insights into the identification of novel targets for both host effectors and microbial factors and will lead to new therapeutic treatments for infections and other inflammatory diseases.

Pathogen effectors: What do they do at plasmodesmata?

Plants perceive an assortment of external cues during their life cycle, including abiotic and biotic stressors. Biotic stress from a variety of pathogens, including viruses, oomycetes, fungi, and bacteria, is considered to be a substantial factor hindering plant growth and development. To hijack the host cell's defence machinery, plant pathogens have evolved sophisticated attack strategies mediated by numerous effector proteins. Several studies have indicated that plasmodesmata (PD), symplasmic pores that facilitate cell‐to‐cell communication between a cell and neighbouring cells, are one of the targets of pathogen effectors. However, in contrast to plant‐pathogenic viruses, reports of fungal‐ and bacterial‐encoded effectors that localize to and exploit PD are limited. Surprisingly, a recent study of PD‐associated bacterial effectors has shown that a number of bacterial effectors undergo cell‐to‐cell movement via PD. Here we summarize and highlight recent advances in the study of PD‐associated fungal/oomycete/bacterial effectors. We also discuss how pathogen effectors interfere with host defence mechanisms in the context of PD regulation.

A clubroot pathogen effector targets cruciferous cysteine proteases to suppress plant immunity

ABSTRACT Plant pathogen effector proteins are key to pathogen virulence. In susceptible host Brassicas, the clubroot pathogen, Plasmodiophora brassicae, induces the production of nutrient-sink root galls, at the site of infection. Among a list of 32 P. brassiae effector candidates previously reported by our group, we identified SSPbP53 as a putative apoplastic cystatin-like protein highly expressed during the secondary infection. Here we found that SSPbP53 encoding gene is conserved among several P. brassicae pathotypes and that SSPbP53 is an apoplastic protein able to directly interact with and inhibit cruciferous papain-like cysteine proteases (PLCPs), specifically Arabidopsis XYLEM CYSTEINE PEPTIDASE 1 (AtXCP1). The severity of clubroot disease is greatly reduced in the Arabidopsis xcp1 null mutant (AtΔxcp1) after infection with P. brassicae resting spores, indicating that the interaction of P. brassicae SSPbP53 with XCP1 is important to clubroot susceptibility. SSPbP53 is the first cystatin-like effector identified and characterized for a plant pathogenic protist.

Evolutionarily distinct resistance proteins detect a pathogen effector through its association with different host targets.

Knowledge of the evolutionary processes which govern pathogen recognition is critical to understanding durable disease resistance. We determined how Phytophthora infestans effector PiAVR2 is recognised by evolutionarily distinct resistance proteins R2 and Rpi-mcq1. We employed yeast two-hybrid, co-immunoprecipitation, virus-induced gene silencing, transient overexpression, and phosphatase activity assays to investigate the contributions of BSL phosphatases to R2- and Rpi-mcq1-mediated hypersensitive response (R2 HR and Rpi-mcq1 HR, respectively). Silencing PiAVR2 target BSL1 compromises R2 HR. Rpi-mcq1 HR is compromised only when BSL2 and BSL3 are silenced. BSL1 overexpression increases R2 HR and compromises Rpi-mcq1. However, overexpression of BSL2 or BSL3 enhances Rpi-mcq1 and compromises R2 HR. Okadaic acid, which inhibits BSL phosphatase activity, suppresses both recognition events. Moreover, expression of a BSL1 phosphatase-dead (PD) mutant suppresses R2 HR, whereas BSL2-PD and BSL3-PD mutants suppress Rpi-mcq1 HR. R2 interacts with BSL1 in the presence of PiAVR2, but not with BSL2 and BSL3, whereas no interactions were detected between Rpi-mcq1 and BSLs. Thus, BSL1 activity and association with R2 determine recognition of PiAVR2 by R2, whereas BSL2 and BSL3 mediate Rpi-mcq1 perception of PiAVR2. R2 and Rpi-mcq1 utilise distinct mechanisms to detect PiAVR2 based on association with different BSLs, highlighting central roles of these effector targets for both disease and disease resistance.

SUMOylation in Phytopathogen Interactions: Balancing Invasion and Resistance.

Plants are constantly confronted by a multitude of biotic stresses involving a myriad of pathogens. In crops, pathogen infections result in significant agronomical losses worldwide posing a threat to food security. In order to enter plant tissues and establish a successful infection, phytopathogens have to surpass several physical, and chemical defense barriers. In recent years, post-translational modification (PTM) mechanisms have emerged as key players in plant defense against pathogens. PTMs allow a highly dynamic and rapid response in front of external challenges, increasing the complexity and precision of cellular responses. In this review, we focus on the role of SUMO conjugation (SUMOylation) in plant immunity against fungi, bacteria, and viruses. In plants, SUMO regulates multiple biological processes, ranging from development to responses arising from environmental challenges. During pathogen attack, SUMO not only modulates the activity of plant defense components, but also serves as a target of pathogen effectors, highlighting its broad role in plant immunity. Here, we summarize known pathogenic strategies targeting plant SUMOylation and, the plant SUMO conjugates involved in host-pathogen interactions. We also provide a catalog of candidate SUMO conjugates according to their role in defense responses. Finally, we discuss the complex role of SUMO in plant defense, focusing on key biological and experimental aspects that contribute to some controversial conclusions, and the opportunities for improving agricultural productivity by engineering SUMOylation in crop species.

Amoebae as Targets for Toxins or Effectors Secreted by Mammalian Pathogens.

Numerous microorganisms, pathogenic for mammals, come from the environment where they encounter predators such as free-living amoebae (FLA). The selective pressure due to this interaction could have generated virulence traits that are deleterious for amoebae and represents a weapon against mammals. Toxins are one of these powerful tools that are essential for bacteria or fungi to survive. Which amoebae are used as a model to study the effects of toxins? What amoeba functions have been reported to be disrupted by toxins and bacterial secreted factors? Do bacteria and fungi effectors affect eukaryotic cells similarly? Here, we review some studies allowing to answer these questions, highlighting the necessity to extend investigations of microbial pathogenicity, from mammals to the environmental reservoir that are amoebae.