CD40 Ligand Research Articles

Atheroprotective CD40-TRAF6 inhibitors: translational pipeline towards a clinical application

Abstract Background The co-stimulatory CD40–CD40 ligand axis is central in atherogenesis. Upon activation, CD40 recruits tumor necrosis factor receptor-associated factors (TRAFs) to induce downstream signaling. Murine studies with mutated CD40-TRAF binding sites in macrophages have shown that the CD40-TRAF6, rather than CD40-TRAF2/3/5, axis is crucial for atherosclerosis. We thus synthesized the small molecule inhibitor TRAF-STOP 6877002, that selectively blocks CD40-TRAF6 signaling. 6877002 successfully reduced the onset and development of atherosclerosis by reducing monocyte recruitment and macrophage activation in ApoE-/- mice without having immunosuppressive side effects. Purpose To assess whether 6877002 is a suitable candidate to pass the translational pipeline towards a clinical application. Methods Elaborate in vitro and in vivo assays evaluating the pharmacological properties and potential toxicity of 6877002. Results Together with Cyprotex, we performed in vitro assays examining the ADME profile of 6877002. In an intestinal permeability assay, 6877002 had low to moderate resorption with no significant efflux, suggesting it is not a substrate for the efflux transporters Pgp/BCRP or MRP2. A plasma protein binding assay showed very low unbound 6877002 fractions, indicating that it is highly bound to plasma proteins. The potential to inhibit cytochrome P450 enzymes was assessed using human liver microsomes in the presence of enzyme-specific probe substrates. While 6877002 inhibited CYP1A2 (IC50=4.01 µM), no potential for inhibiting other CYP isoforms was detected, suggesting low drug-drug interaction potential. To screen for putative cardiovascular risks, hERG ion channel inhibition was assessed and no IC50 could be determined. Hepatic clearance was rapid in mice, rats and dogs, while minipig and human hepatocytes had lower intrinsic clearance. Together with Aptuit, we developed suitable formulations for oral and i.v. administration. In vivo pharmacokinetics studies in rats showed low bioavailability (8.43%) and rapid clearance of orally administered 6877002 compared to i.v. injected 6877002, likely – and in line with our in vitro data – due to fast first-past effect in mouse hepatocytes and uptake by macrophages. To explain the high efficacy of 6877002 despite its rapid metabolism, we assessed whether 6877002 has active metabolites that bind the CD40-TRAF6 pocket and performed an LC-MS/MS-based metabolite profiling. We detected 17 metabolites. Further MD simulations confirmed that Metabolite (M)4, the most abundant metabolite, binds the CD40-TRAF6 pocket, reflected by the highest binding mode (-19.6; defined as Binding Free Energy derived from 40-50 ns of MD run as compared to -16.5 for 6877002). Similar to 6877002, M4 reduced atherosclerosis by 54% in Western diet-fed ApoE-/- mice, indicative of M4 being an active metabolite. Conclusion CD40-TRAF6 inhibitors are an attractive strategy to combat atherosclerosis with high translational potential.

Immune Mediators Profiles in the Aqueous Humor of Patients with Simple Diabetic Retinopathy.

Various immune mediators identified to date are associated with the development of advanced forms of diabetic retinopathy (DR), such as proliferative DR and diabetic macular edema, although the exact pathophysiological mechanisms of early stages of DR such as simple DR remain unclear. We determined the immune mediator profile in the aqueous humor of eyes with simple DR. Fifteen eyes of fifteen patients with simple DR were studied. Twenty-two eyes of twenty-two patients with cataracts and no DR served as controls. Undiluted aqueous humor samples were collected, and a cytometric bead array was used to determine the aqueous humor concentrations of 32 immune mediators comprising 13 interleukins (IL), interferon-γ, interferon-γ-inducible protein-10 (IP-10), monocyte chemoattractant protein-1, macrophage inflammatory protein (MIP)-1α, MIP-1β, regulated on activation, normal T cell expressed and secreted (RANTES), monokine induced by interferon-γ, basic fibroblast growth factor (bFGF), Fas ligand, granzyme A, granzyme B, interferon-inducible T-cell alpha chemoattractant (ITAC), fractalkine, granulocyte macrophage colony-stimulating factor, granulocyte colony-stimulating factor (G-CSF), vascular endothelial growth factor (VEGF), angiogenin, tumor necrosis factor-α, and CD40 ligand. Among the 32 immune mediators, 10 immune mediators, including bFGF, CD40 ligand, fractalkine, G-CSF, IL-6, IL-8, MIP-α, MIP-1β, and VEGF, showed significantly higher aqueous humor concentrations and the Fas ligand had significantly lower concentration (p < 0.05) in eyes with simple DR compared with control eyes. Of these 10 cytokines with significant concentration alteration, protein-protein interaction analysis revealed that 8 established an intricate interaction network. Various immune mediators may contribute to the pathogenesis of simple DR. Attention should be given to the concentrations of immune mediators in ocular fluids even in simple DR. Large-scale studies are warranted to assess whether altered aqueous humor concentrations of these 10 immune mediators are associated with an increased risk of progression to advanced stages of DR.

SDC2 Expression Is Increased in Myeloma Cells in Response to Loss of Pro-Survival Surface Proteins, CD28 and CD86

Introduction: While recent advances in multiple myeloma (MM) have improved overall survival, most patients will succumb to late-stage and drug resistant disease. Plasma cell (PC) survival outside of the bone marrow is characteristic of late-stage myeloma and pivotal to disease progression. PCs are typically restricted to the bone marrow microenvironment, as they are dependent on stromal interactions for survival. One such interaction is the engagement of CD28 and its ligand CD86, proteins which are best understood for their roles in T-cell activation by antigen presenting cells. However, myeloma cells can express both CD28 and CD86 on the cell surface. Notably, high CD28 expression is seen in 59% of medullary recurrences, and over 90% of extramedullary relapses. Moreover, high CD86 expression is more common in malignant plasma cells as compared to precursor stages and has a reported role in driving expression of IRF4. We have previously shown that expression of CD28 and CD86 is associated with worse outcomes than that observed in patients with low expression in the MMRF CoMMpass study (NCT01454297). We have also shown that silencing of CD28 or CD86 results in cell death and loss of IRF4 protein expression in human myeloma cell lines (HMCL). We confirmed these studies using CRISPR/Cas9 editing and demonstrated loss of proliferation and induction of cell death in HMCLs. However, the mechanism(s) by which CD28 and CD86 contribute to MM cell survival is not fully understood. Methods: To shed light on the mechanistic basis of CD28 and CD86 in the survival of MM, we used CRISPR/Cas9 editing to disrupt expression from RPMI8226 myeloma cells. We then passaged transduced cells to select for populations that can survive loss of CD28 or CD86. These passaged cells were sorted into populations that either retained CD28 or CD86 expression as transduction controls (High), or populations that underwent CRISPR/Cas9 depletion (Low). Surface expression of CD28 High/Low and CD86 High/Low populations was confirmed via flow cytometry and were then processed for RNA isolation and cDNA library preparation. RNA-sequencing was performed using paired-end sequencing, and data were aligned using the STAR aligner. Differentially expressed genes were determined using edgeR with an FDR ≤ 0.05 and a fold-change ≥ 2.0. Validation of RNA-sequencing results was further assessed via western blot and flow cytometry. Results: Analysis of RNA-sequencing results indicated that 57 genes were differentially expressed between High and Low cells, with 23 genes common to both CD28 and CD86 High/Low comparisons. (FDR&amp;lt;0.05). Notably, our results reveal that loss of CD28 or CD86 is associated with an increase in mRNA expression of Syndecan-2 (SDC2). In addition, our preliminary experiments evaluating SDC2 surface expression via flow cytometry suggest that both CD28 Low and CD86 Low populations have increased expression of SDC2. Additionally, in the RNA-seq analysis we also observed that CD28 Low and CD86 Low cells were also able to sustain mRNA expression of IRF4. This result was later confirmed via western blot, demonstrating CD28 Low and CD86 Low cells sustain protein expression of IRF4. Conclusions: Our results demonstrate that RPMI8226 cells that lack CD28 or CD86 expression have increased mRNA and protein expression of SDC2, a member the heparan sulfate proteoglycan family. Since SDC2 expression has also been associated with a number of cancers including colorectal, lung, and pancreatic cancers, these results provide insight to potential alternative pathways that contribute to myeloma survival independent of CD28 and CD86 signaling. We also confirmed that CD28- and CD86-depleted populations were able to maintain IRF4 mRNA/protein levels. This indicates myeloma cells have mechanisms to sustain IRF4 expression in addition to CD28 and CD86 signaling. These results are also consistent with previous findings illustrating importance of IRF4 in myeloma. Finally, we have developed CRISPR/Cas9-depleted CD28 and CD86 populations in additional HMCLs. We are currently in the process of isolating CD28 High/Low and CD86 High/Low populations for additional analysis and will present these upcoming results.

Combining Allogeneic Gamma Delta T Cells with a Phosphoantigen Prodrug Promotes Apoptosis of Acute Myeloid Leukemia Stem and Progenitor Cells

Despite recent therapeutic advances, patients with relapsed/refractory acute myeloid leukemia (r/r AML) have limited treatment options and poor prognosis. Leukemic stem cells (LSCs) are considered as relapse-initiating cells and the “culprit” of treatment resistance. Allogeneic and autologous gamma delta (γδ) T cell-based therapies have been explored for a long time and proven to be safe in patients through multiple clinical trials. However, quite a few AML blasts obtained from r/r AML patients show resistance to γδ T cell-mediated cytotoxicity. Novel strategies targeted LSCs may improve efficacy of γδ T cell-mediated r/r AML therapy. Given that γδ T cells exert antitumor capacity via multiple pathways, to identify the way matters most in the resistance of γδ T cell-mediated cytotoxicity, we examined the median fluorescence intensity (MFI) of the ligands expressed in tumor cells by flow cytometry, including butyrophilin 3A (BTN3A), butyrophilin 2A1 (BTN2A1), the human MHC class I chain-related genes (MICA and MICB), the unique-long 16 binding proteins (ULBP1, ULBP2/5/6, ULBP3), Fas, the receptor of TNF-related apoptosis-inducing ligand (TRAIL) DR5, CD112 and CD155. The cytotoxicity activity of γδ T cells was measured by flow cytometry-based killing assay or bright-lite luciferase assay system after coculturing with AML cell lines and blasts at an appropriate effector to target (E:T) ratio. Then we employed a Support Vector Machine model to predict the killing efficiency and identified that BTN3A and BTN2A1 play the predominant role in γδ T cell-mediated cytotoxicity based on the Shapley additive explanation. BTN3A and BTN2A1 are the key ligands in the γδ TCR-phosphoantigen (pAg) recognition activity. PAgs, which are produced in tumor cells function as “molecular glues” to promote heteromeric association of BTN3A1 and BTN2A1 (Yuan L et al., BioRxiv 2022). To promote the γδ T cell-mediated cytotoxicity targeting r/r AML, here we synthesized a pAg prodrug, which show great plasma stability and membrane permeability. We anticipate this small molecule would lead pAg accumulation in tumor cells and cause increased γδ T cell activation. To identify the killing efficacy of pAg prodrug-induced γδ T cell activation, we select KG-1α (a human leukemia stem cell-like cell) as target cell. Zoledronate (ZOL), which is employed to stimulate γδ T cells in multiple γδ T cell-based clinical trials, is used in our killing assay as compared group. As expected, combining γδ T cells with pAg prodrug or ZOL both significantly improved the percent of specific killing when the E:T ratio is 1:1. The pAg prodrug showed more potent activity than ZOL group with EC50 value of 0.1 nM vs 17.93μM. And the specific killing percent of pAg prodrug group is 83.26±2.1 % (1 nM), comparing with negative control 15.17±3.4 % (only γδT cells). Futhermore, at relatively low E:T ratio (1:4), γδ T cells with pAg prodrug remain excellent cytotoxicity when targeting MV411 cell and OCI-AML3 cell, which are widely used in r/r AML research. After coculturing with primary leukemia stem and progenitor cells (CD34 +) obtained from r/r AML patients for 6~8 h, the apoptosis percentage of CD34 + leukemia cells was 42.34% comparing with negative control (only γδT cells) 2.53%. Then we evaluated the in vivo efficacy of combining γδT cells and pAg prodrug in NSG mice bearing MV411 cells. Compared with only γδT cells-treated group, combination with pAg prodrug presented better tumor clearing. To elucidate the pathway of pAg prodrug-mediated killing, we tested mitochondria apoptosis related events. After treated by γδ T cells with pAg prodrug, KG-1α cells showed loss of mitochondrial outer membrane potential and increasingly actived caspase 3/7. Meanwhile, pAg prodrug directly activates effector γδ T cells with increased secretion of CD107a and IFN-γ. Considering the possibility of toxicity towards normal hematopoietic stem and progenitor cells, we conducted colony-forming units (CFUs) assay. After treatment with γδT cells and pAg prodrug, the number of CFUs of CD34 + cells from cord blood was not effected compared with the CD34 + cells only group. Overall, we explored the predominant factor in γδ T cell-mediated killing and synthesized a pAg prodrug to improve the killing efficacy. We demonstrated that combining γδ T cells with pAg prodrug has effectively promoted apoptosis of AML stem and progenitor cells sparing normal hematopoietic stem and progenitor cells.

Targeting T-Cell Lymphoma Using CD70-Directed Cord Blood-Derived CAR-NK Cells

T-cell lymphomas (TCL) are a heterogenous group of non-Hodgkin lymphoma characterized by resistance to conventional therapies posing an urgent need for safe and effective therapies. CAR-NK cells have emerged as a promising “off-the-shelf” cancer immunotherapy and are especially attractive for the treatment of T-cell malignancies. This is especially the case given the challenge of targeting T cell malignancies with CAR T cells due to shared antigens across the therapeutic, normal and malignant T cells posing the risk of CAR T cell fratricide, T-cell aplasia, and contamination of the CAR T products with malignant T cells. We have developed an FDA-approved system for ex vivo NK cell expansion, which reliably generates clinically relevant doses of GMP-grade NK cells from a cord blood (CB) unit. We have used this platform to engineer NK cells to express a CAR targeting CD19 using GMP-grade retroviral vectors and demonstrated the safety and efficacy of this platform in the clinic. We now propose to expand this approach to target TCL. CD70, a surface ligand of CD27, is overexpressed in a variety of cancers, including TCL. Signaling mediated by CD70-CD27 is thought to induce proliferation of TCL cells via activation of the NF-κB pathway. Thus, CD70 is an attractive target for CAR NK-cell therapy against TCL. We analyzed the publicly available primary TCL dataset (GSE19069) including anaplastic large cell lymphoma (30 samples), angioimmunoblastic TCL (37 samples), peripheral TCL (PTCL; 50 samples), and adult T cell leukemia/lymphoma (13 samples) for CD70 expression. The majority of the samples expressed CD70 transcript with a variable level of expression ( Figure 1). Using flow cytometry, we screened a panel of TCL cell lines with diverse histologic, cytogenetic and molecular properties for the expression of CD70. We demonstrated positive CD70 expression on most of the TCL cell lines profiled encompassing anaplastic large cell lymphoma (ALK+: KAR299; ALK-: MAC2A; fusion gene NPM-ALK+: SU-DHL1 and SUP-M2), hepatosplenic gamma-delta TCL (DERL-7), Sezary syndrome (SS; H9 and HuT78), and PTCL NOS (OCI-LY12). The CD70 intensity was highest on MAC2A, HuT78, KAR299 and SUP-M2, intermediate to low on DERL-7 and H9, and negative on SU-DHL1 and OCI-LY12. We designed a novel retroviral vector targeting CD70 that: 1) encodes the CD70-targeting CAR gene based on the CD27 extracellular domain; 2) ectopically produces interleukin (IL)-15 to support NK cell proliferation; and 3) expresses the suicide gene inducible caspase 9 ( iC9) that can be pharmacologically activated to eliminate transduced cells in the event of toxicity. The construct will be referred to as CAR.70/IL-15. Non-transduced (NT) NK cells and NK cells transduced with a construct that leads to IL-15 production without a CAR (IL-15 NK cells) were used as controls. We demonstrated that CAR.70/IL-15 NK cells had a significantly enhanced cytotoxicity compared to NT- and IL-15 NK cells against the CD70+ cell lines while there was no difference in cytotoxicity between the NK cell conditions in the negative cell lines pointing to a CD70-targeted fashion of anti-TCL NK cell cytotoxicity. Moreover, CAR.70/IL-15 NK cells exhibited greater cytotoxicity against CD70+ cell lines in long-term cytotoxicity assays ( Figure 2). In a tumor rechallenge assay against KAR299 where fresh tumor cells were added every 3-4 days, CAR.70/IL-15 NK cells showed superior potency in continuous tumor control. In addition, CAR.70/IL-15 NK cells exhibited higher levels of degranulation (CD107a) and cytokine production (TNFα and INF-γ) when cocultured with CD70+ TCL cell lines, compared to NT and IL-15 NK cells. Furthermore, these CAR NK cells targeting CD70 outperformed CAR NK cells engineered to target CD19, which is an irrelevant target for TCL, further confirming the specific CD70-targeted activity of CAR.70/IL-15 NK cells. CyTOF immunophenotyping revealed that CAR.70/IL-15 NK cells are characterized by the increased expression of markers of cytotoxicity such as granzyme-b, perforin, TRAIL; and activating coreceptors/proliferation markers such as DNAM, CD25 and Ki67. Taken together, our findings validate CD70 as a promising target for TCL treatment using CAR NK cells. Our approach provides a solid foundation for the clinical translation of CD70-targeting CAR NK-cell therapy for patients with TCL.

Enhancing MHC-Independent T Cell Receptors Using Rational Protein Engineering

The paradigm of synthetic receptors, chimeric antigen receptors (CARs), combine MHC-independence with T cell activation. While T cells engineered to express CARs are successful for some patients, the majority are not cured and clinical failures often result from CAR-driven T cell dysfunction (Lynn R, Nature 2019; Selli ME, Blood 2023). Simultaneously, many patients develop cytokine release syndrome, a hyperinflammatory state resulting from uncontrolled CAR-driven immune activation, indicating that CARs can drive both failure and toxicity. We hypothesized that these limitations result from CAR design which, in its simplicity, bypasses natural TCR regulation. To re-engage endogenous T cell regulatory circuits, we replaced the variable region of the TCR α and β chains with the CD19 binding domain used in several clinical CAR constructs. As shown recently by others (Liu Y, Sci Transl Med 2021; Mansilla-Soto Nature Medicine 2022), we found that this format of synthetic receptor expressed on the cell surface, clustered with endogenous CD3 molecules, and drove T cell cytotoxicity against CD19+ leukemia (Nalm6). Intriguingly, surface expression of these MHC-independent TCRs (miTCR) was markedly reduced in comparison to transgenic full-length TCRs and CARs. Examination of the chimeric interface created by joining the antibody and TCR parent chains revealed significant biochemical conflicts that, based on predictive modeling, disrupted naturally-occurring hydrostatic interactions and associated hydrogen bonds, collectively resulting in steric “strain” on the miTCR. We generated a series of miTCR mutants which resolved these conflicts in a step-wise fashion to more closely approximate the “relaxed” state of endogenous TCRs. We found that most mutations improved miTCR surface expression, and more importantly that some mutations significantly boosted T cell functionality as compared to the wild-type miTCR. Impressively, one mutant that closely approximated endogenous TCR structure (mut035) enabled functionality similar to CD19 CARs in short-term cytotoxicity assays. To further evaluate the functional implications of targeted interface mutation, we subjected miTCRs to chronic in vitro stimulation assays in which engineered T cells are exposed to high quantities of Nalm6 for prolonged periods until T cell lose function. We observed that mut035 outperformed all other miTCRs, but all miTCR T cells lost the ability to kill targets earlier than CAR T cells. To determine if a lack of costimulation was the cause of this reduced efficacy we engineered Nalm6 cells to express ligands for CD28 (CD80) and 41BB (41BBL). In the presence of these ligands, long-term functionality all miTCR T cells was profoundly improved. Notably, mut035 T cells persisted longer and killed Nalm6 better than CD19 CAR T cells under conditions of persistent and high-intensity stimulation. Finally, to determine if CD28 or 41BB engagement was most supportive of miTCR function we designed a “priming” experiment. miTCR T cells were initially cultured with Nalm6 expressing either no, one or both costimulatory ligands and then, after tumor clearance, were re-challenged with WT Nalm6, mirroring endogenous immune responses to infection. mut035 T cells initially exposed to CD80 were unable to clear WT cells on re-challenge, however priming with 41BBL enabled potent and prolonged co-stimulation-independent killing of large Nalm6 burdens, suggesting engagement of endogenous T cell functionality. These data demonstrate that classical approaches to combine protein domains can lead to biochemical conflicts that restrain chimeric protein function. Targeted mutation significantly enhanced miTCR function to exceed CAR under conditions of high-burden, high-antigen tumors.

A Phase 1 Study of PIT565, a First-in-Class, Anti-CD3, Anti-CD19, Anti-CD2 Trispecific Antibody in Patients with Relapsed and/or Refractory B-Cell Malignancies

Background and Significance: There is an unmet therapeutic need for patients with relapsed and/or refractory (R/R) B-cell non-Hodgkin lymphoma (B-NHL) and R/R B-cell acute lymphoblastic leukemia (B-ALL) who have failed multiple lines of therapy. PIT565 is an investigational, first-in-class, immunoglobulin G-like, trispecific antibody that targets CD19 on malignant B cells while engaging CD3 and CD2 (a costimulatory receptor) on T cells, leading to redirected T-cell cytotoxicity toward CD19-positive malignant B cells. CD2 signaling prevents transcriptional changes characteristic of exhaustion during persistent T-cell receptor stimulation of CD8 T cells. Furthermore, the loss of CD2 ligand, CD58, on tumor cells has been shown to mediate resistance to the antitumor activity by T cell-redirecting therapies, confirming the importance of CD2 activation in T cells. Findings from preclinical studies suggest that PIT565 mediates more potent and sustained antitumor T-cell responses compared with CD3 bispecifics (Lu H, ASH 2022). Study Design and Methods: This is an open-label, phase 1, multicenter study of PIT565 in patients with R/R B-NHL and R/R CD19-positive B-ALL who have relapsed/failed to respond to ≥2 lines of prior therapy (including an anti-CD20 monoclonal antibody-containing chemotherapy combination regimen for patients with R/R B-NHL) (NCT05397496). The study is ongoing with plans to enroll approximately 140 patients in Belgium, France, Israel, Italy, Japan, Singapore, Spain, and the USA. Eligible patients are ≥18 years with an Eastern Cooperative Oncology Group performance status ≤2 and have at least one bi-dimensionally measurable nodal lesion or one bi-dimensionally measurable extranodal lesion as measured via positron emission tomography-computed tomography for R/R B-NHL, and/ or morphologic disease in the bone marrow (³5% blasts) for R/R B-ALL. Patients with contraindication to tocilizumab; history of other malignant disease; active central nervous system involvement; autoimmune disease (other than patients with vitiligo, hypothyroidism only requiring hormone replacement, or psoriasis not requiring systemic treatment or conditions not expected to recur); or receiving systemic treatment with any immunosuppressive medication are not eligible. During the dose escalation part of the study, PIT565 is administered to patients with R/R B-NHL (Group A) and patients with R/R B-ALL (Group B). During the dose-expansion part, PIT565 is administered to patients with R/R large B-cell lymphoma (LBCL) who have received CD-19-directed chimeric antigen receptor (CAR)-T therapy (Group A1); patients with R/R LBCL who have not received CAR-T therapy (Group A2); and patients with R/R B-ALL (Group B1). PIT565 is administered either once weekly (Q1W) or once every 2 weeks (Q2W) with and without a priming dosing. Routes of administration (intravenous [IV] or subcutaneous [SC]) are explored in the dose-escalation phase. Patients initially receive PIT565 IV Q1W over a 28-day cycle. Q2W treatment in a 28-day cycle is explored if supported by preliminary pharmacokinetics (PK), pharmacodynamics, efficacy, and safety findings. The primary objective is to assess safety (including dose-limiting toxicities) and tolerability, and to identify the maximum tolerated dose (MTD) and/or recommended dose (RD), schedule, and route of administration for each indication. Secondary objectives include evaluation of preliminary antitumor activity (overall response rate, complete response rate, best overall response, duration of response, overall survival, and progression-free survival for B-NHL or event-free survival for B-ALL), assessment of PK and immunogenicity of PIT565 in R/R B-NHL and R/R B-ALL. The dose escalation phase is guided by an adaptive Bayesian logistic regression model following the escalation with overdose control principle. The MTD and/or RD are further explored during the dose-expansion phase.

CD40 Ligand-CD40 Interaction Is an Intermediary between Inflammation and Angiogenesis in Proliferative Diabetic Retinopathy.

We aimed to investigate the role of the CD40-CD40 ligand (CD40L) pathway in inflammation-mediated angiogenesis in proliferative diabetic retinopathy (PDR). We analyzed vitreous fluids and epiretinal fibrovascular membranes from PDR and nondiabetic patients, cultures of human retinal microvascular endothelial cells (HRMECs) and Müller glial cells and rat retinas with ELISA, immunohistochemistry, flow cytometry and Western blot analysis. Functional tests included measurement of blood-retinal barrier breakdown, in vitro angiogenesis and assessment of monocyte-HRMEC adherence. CD40L and CD40 levels were significantly increased in PDR vitreous samples. We demonstrated CD40L and CD40 expression in vascular endothelial cells, leukocytes and myofibroblasts in epiretinal membranes. Intravitreal administration of soluble (s)CD40L in normal rats significantly increased retinal vascular permeability and induced significant upregulation of phospho-ERK1/2, VEGF, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1). sCD40L induced upregulation of VEGF, MMP-9, MCP-1 and HMGB1 in cultured Müller cells and phospo-ERK1/2, p65 subunit of NF-ĸB, VCAM-1 and VEGF in cultured HRMECS. TNF-α induced significant upregulation of CD40 in HRMECs and Müller cells and VEGF induced significant upregulation of CD40 in HRMECs. sCD40L induced proliferation and migration of HRMECs. We provide experimental evidence supporting the involvement of the CD40L-CD40 pathway and how it regulates inflammatory angiogenesis in PDR.

Metabolic syndrome, soluble CD40L, and biomarkers of endothelial dysfunction in people living with HIV.

In the present study, we aimed to investigate the association between soluble CD40 ligand (sCD40L, a marker of platelet activation), soluble thrombomodulin, and syndecan-1 (both well-described markers of endothelial dysfunction) and metabolic syndrome in a large cohort of well-treated people with HIV (PWH) and to elucidate their association with HIV-specific variables. We included 862 PWH with undetectable viral replication. Our hypotheses were tested using uni- and multivariable logistic regression models a priori adjusted for well-known confounders. While no association of soluble thrombomodulin and syndecan-1 with MetS was found, high levels of sCD40L (aOR 1.54 [1.07-2.22]) were associated with excess risk of MetS. Given the previously described association between sCD40L, vascular inflammation and endothelial damage, the results presented in our study may suggest a potential role for sCD40L in the well-known association between cardiometabolic comorbidity and HIV infection.

Phagocytosis-initiated tumor hybrid cells acquire a c-Myc-mediated quasi-polarization state for immunoevasion and distant dissemination

While macrophage phagocytosis is an immune defense mechanism against invading cellular organisms, cancer cells expressing the CD47 ligand send forward signals to repel this engulfment. Here we report that the reverse signaling using CD47 as a receptor additionally enhances a pro-survival function of prostate cancer cells under phagocytic attack. Although low CD47-expressing cancer cells still allow phagocytosis, the reverse signaling delays the process, leading to incomplete digestion of the entrapped cells and subsequent tumor hybrid cell (THC) formation. Viable THCs acquire c-Myc from parental cancer cells to upregulate both M1- and M2-like macrophage polarization genes. Consequently, THCs imitating dual macrophage features can confound immunosurveillance, gaining survival advantage in the host. Furthermore, these cells intrinsically express low levels of androgen receptor and its targets, resembling an adenocarcinoma-immune subtype of metastatic castration-resistant prostate cancer. Therefore, phagocytosis-generated THCs may represent a potential target for treating the disease.

Investigation of Immunostimulatory Effects of IFN-γ Cytokine and CD40 Ligand Costimulatory Molecule for Development of HIV-1 Therapeutic Vaccine Candidate.

The most crucial disadvantage of DNA-based vaccines is their low immunogenicity; therefore, finding an effectual adjuvant is essential for their development. Herein, immunostimulatory effects of IFNγ cytokine and a CD40 ligand (CD40L) costimulatory molecule are evaluated as combined with an antigen, and also linked to an antigen in mice. For this purpose, after preparation of the HIV-1 Nef, IFNγ, and CD40L DNA constructs, and also their recombinant protein in an Escherichia coli expression system, nine groups of female BALB/c mice are immunized with different regimens of DNA constructs. About 3 weeks and also 3 months after the last injection, humoral and cellular immune responses are assessed in mice sera and splenocytes. Additionally, mice splenocytes are exposed to single-cycle replicable (SCR) HIV-1 virions for evaluating their potency in the secretion of cytokines in vitro. The data indicate that the linkage of IFNγ and CD40L to Nef antigen can significantly induce the Th-1 pathway and activate cytotoxic T lymphocytes compared to other regimens. Moreover, groups receiving the IFNγ-Nef and CD40L-Nef fusion DNA constructs show higher secretion of IFNγ and TNF-α from virion-infected lymphocytes than other groups. Therefore, the IFNγ-Nef and CD40L-Nef fusion DNA constructs are suggested to be a potential option for development of an efficient HIV-1 vaccine.

Inflammation induces α1-adrenoceptor expression in peripheral blood mononuclear cells of patients with complex regional pain syndrome

Persistent regional and systemic inflammation may promote pain and hyperalgesia in complex regional pain syndrome (CRPS). In this study, we investigated whether stimulation of α1-adrenoceptors (α1-AR) on peripheral blood mononuclear cells (PBMC) might contribute to this inflammatory state. PBMC were isolated from venous blood collected from 21 CRPS patients and 21 sex and age-matched controls. Lipopolysaccharide (LPS), a bacterial toxin, was administered to cultured PBMC for 24 h to trigger inflammation. Exposure to LPS resulted in heightened gene expression of α1-AR subtype B (α1B-AR) in PBMC of CRPS patients relative to controls. Interleukin (IL)-1β and IL-6 levels did not change when the α1-AR agonist phenylephrine was administered to naïve PBMC. However, α1-AR stimulation following LPS treatment increased IL-6 mRNA and protein levels in PBMC of patients and controls. To investigate the possible consequence of heightened IL-6 levels on immunoglobulin G antibody production, PBMC were stimulated with CD40 ligand and IL-21 to generate plasmablasts (B cells that secrete antibodies). This response was similar in patients and controls. Adding IL-6 to the cell culture medium increased plasmablast differentiation in controls and antibody production both in patients and controls. These findings suggest that the inflammatory cascade associated with elevated levels of IL-6 may generate α1B-AR expression in CRPS PBMC. A reciprocal interaction between heightened α1-AR expression in PBMC and IL-6 secretion may contribute to systemic inflammation and antibody production in CRPS.

Reduced Relapse-Free Survival in Colorectal Cancer Patients with Elevated Soluble CD40 Ligand Levels Improved by Vitamin D Supplementation.

Although elevated serum levels of soluble CD40 ligand (sCD40L) were reported in patients with cancer, the importance of high sCD40L levels in clinical oncology remains unknown. We conducted a post hoc analysis of the AMATERASU randomized clinical trial of vitamin D3 supplementation (2000 IU/day) in patients with digestive tract cancer to assess its significance. Serum sCD40L levels were measured by ELISA in 294 residual samples, and were divided into tertiles. In patients with colorectal cancer (CRC), 5-year relapse-free survival (RFS) rates in the middle and highest tertiles were 61.6% and 61.2%, respectively, which was significantly lower than 83.8% in the lowest tertile. A Cox proportional hazard analysis showed that the lowest tertile had a significantly lower risk of relapse or death than the highest tertile even with multivariate adjustment (hazard ratio (HR), 0.30; 95% confidence interval (CI), 0.11-0.80; p = 0.016). In the subgroup of CRC patients with the highest tertile of sCD40L, the 5-year RFS rate in the vitamin D group was 77.9%, which was significantly higher than 33.2% in the placebo group (HR, 0.30; 95% CI, 0.11-0.81; p = 0.018 [Pinteraction = 0.04]). In conclusion, elevated sCD40L might be a biomarker of poor prognosis in patients with CRC, but vitamin D supplementation might improve RFS in patients with high sCD40L.

Abnormal immune function of B lymphocyte in peripheral blood of Parkinson's disease

BackgroundParkinson's disease (PD) is associated with peripheral inflammation and abnormal peripheral blood lymphocyte immune responses. Peripheral blood B-lymphocyte subset distributions and whether they are associated with PD are unclear. MethodsSixty-one PD patients and sixty-one one-to-one paired healthy controls (HCs) were enrolled. We used flow cytometry to perform immunophenotyping of peripheral B-lymphocyte, in vitro stimulation and measured serum cytokine. The relationship between variables and PD were assessed. ResultsThe percentage of naive B cells in blood of PD patients was decreased, whereas the percentages of regulatory B cells (Bregs), plasma blast cells (PBCs), and double-negative (DN) B cells were increased. The absolute counts of B-lymphocyte and naive B cells in blood of PD patients were decreased. Regression analysis revealed that alterations in the absolute counts of B-lymphocyte and the percentage of Bregs and DN B cells were associated with PD. After stimulation, the percentages of Bregs, PBCs, and switched memory (SwM) B cells increased in PD patients. Additionally, increases in GM-CSF-producing B-cell, IFN-γ-producing B-cell, and TNF-α-producing B-cell percentages were noted in PD. Serum levels of a proliferation-inducing ligand (APRIL), B-cell activating factor (BAFF) and soluble CD40 ligand (sCD40L) were elevated in PD and correlated negatively with the UPDRS III score. ConclusionsAbnormal B-lymphocyte immune responses in peripheral blood may contribute to PD development. Alterations in the absolute counts of B-lymphocyte and the percentage of Bregs and DN B cells are associated with PD. Furthermore, APRIL, BAFF, and sCD40L could be potential targets for intervention in PD.

In vivo transfection of cytokine genes into tumor cells using a synthetic vehicle promotes antitumor immune responses in a visceral tumor model.

The tumor microenvironment (TME) strongly affects the clinical outcomes of immunotherapy. This study aimed to activate the antitumor immune response by manipulating the TME by transfecting genes encoding relevant cytokines into tumor cells using a synthetic vehicle, which is designed to target tumor cells and promote the expression of transfected genes. Lung tumors were formed by injecting CT26.WT intravenously into BALB/c mice. Upon intravenous injection of the green fluorescent protein-coding plasmid encapsulated in the vehicle, 14.2% tumor-specific expression was observed. Transfection of the granulocyte-macrophage colony-stimulating factor (GM-CSF) and CD40 ligand (L)-plasmid combination and interferon gamma (IFNγ) and CD40L-plasmid combination showed 45.5% and 54.5% complete remission (CR), respectively, on day 60; alternate treatments with both the plasmid combinations elicited 66.7% CR, while the control animals died within 48 days. Immune status analysis revealed that the density of dendritic cells significantly increased in tumors, particularly after GM-CSF- and CD40L-gene transfection, while that of regulatory T cells significantly decreased. The proportion of activated killer cells and antitumoral macrophages significantly increased, specifically after IFNγ and CD40L transfection. Furthermore, the level of the immune escape molecule programmed death ligand-1 decreased in tumors after transfecting these cytokine genes. As a result, tumor cell-specific transfection of these cytokine genes by the synthetic vehicle significantly promotes antitumor immune responses in the TME, a key aim for visceral tumor therapy.

Relationship among serum TIMP-1, sCD40L and peripheral neuropathy in type 2 diabetes

Purpose: To determine the correlation of serum TIMP-1 and sCD40L with peripheral neuropathy in type 2 diabetes (T2DM), and potential targets for pharmacological intervention.Methods: The study enrolled 97 subjects with T2DM. The 41 subjects with simple diabetes were classified as T2DM group, while 56 subjects with diabetic peripheral neuropathy (DPN) were included in the DPN group. A control group consisting of 50 healthy volunteers who conducted health checks during a similar time-period was also included. Clinical data and parameters were compared among the three groups, and TIMP-1 and sCD40L levels were determined. Univariate and multivariate logistic regression analyses were conducted to identify factors affecting DPN. The diagnostic value of TIMP-1 and sCD40L in DPN was also determined.Results: Body mass index (BMI) varied among the three groups (p &lt; 0.05), but age or gender were not significantly different (p &lt; 0.05). Duration of diabetes was longer in DPN group than in T2DM group (p &lt; 0.05). The study also revealed statistically significant differences in fasting blood glucose (FBS), postprandial blood glucose, and glycosylated hemoglobin among the three groups. Tissue inhibitor of metalloproteinase-1 (TIMP-1) and soluble CD40 ligand (sCD40L) were important factors that affected the occurrence of diabetic peripheral neuropathy (p &lt; 0.05).Conclusion: TIMP-1 and sCD40L levels reflect neurovascular injury in patients with diabetes, with potential as targets for pharmacological intervention for peripheral neuropathy. These findings espouse crucial clinical implications for early identification and treatment in type 2 diabetes.

Radiation Therapy Sensitizes Head-and-Neck Cancer Cells to Killing by Chimeric Antigen Receptor (CAR)-NK Cells Targeting CD70

CAR-T cell therapy is limited by toxicity, high cost, logistical manufacturing issues in the autologous setting and risk of GVHD in the allogeneic setting. Substitution of T cells with NK cells opens the possibility for an allogeneic off-the-shelf product with a better safety profile. However, the inadequate efficacy of CAR-NK cells against solid tumors can be extrapolated from experience with CAR-T cells. There is limited but promising preclinical evidence that radiation therapy (RT) enhances CAR-T cell tumoricidal activity against solid tumors. However, there is no data examining the potential synergy between RT and CAR-NK cell therapy. We engineered CAR-NK cells with CD27 receptor as extracellular domain to target its natural ligand CD70, which is overexpressed in head-and-neck cancers (HNSCC). CAR-NK cell killing was assessed real-time through xCELLigence cytotoxicity assays. CD70+ OQ01 human HNSCCs were used for most experiments. FaDu is a CD70- HNSCC (negative ctrl). UMRC3 is a CD70+ kidney cancer cell line (positive ctrl). CD70 expression pre- and post-RT was assessed by flow cytometry and Western blot. Ionizing RT was compared at 5 doses: 0, 1.75, 3.5, 7, and 14 Gy. A single dose of 3.5 Gy was used for most experiments. Post-radiation effects were generally assessed at 3 days or 9 days post-RT. Intracellular staining was used to assess NK cell expression of IFN-γ, CD107a, and TNF-α by flow cytometry. CD27/CD70 interaction blockade was through α-CD27 pre-treatment of CAR-NK cells. OQ01 HNSCCs heterogeneously express CD70 and are killed by CD70 CAR-NK cells in vitro. Pre-conditioning low-dose RT of 3.5 Gy applied to OQ01 HNSCCs 3 days prior to coculture with NK cells enhances CD70 CAR-NK cell killing, with ∼30% increased cytotoxicity against the tumor cells. Low-dose RT by itself did not induce acute cytolysis. As a possible mechanism for the increased sensitivity of irradiated OQ01 cells to CD70 CAR-NK cells, we found that RT enhances CD70 expression among HNSCCs in a dose-dependent manner. There was no increase in NK cell expression of IFN-γ, CD107a, and TNF-α with exposure to irradiated target cells. CD27/CD70 blockade does not solely abrogate RT-induced sensitization toward CAR-NK cell killing. Despite RT induction of transient increased expression of CD70, which normalizes by 9 days post-RT, there is persistent increase in RT-synergized target cell killing even at this later timepoint. Thus, altogether, RT sensitizes CD70-expressing HNSCC cells to CAR-NK cell killing in vitro. This work represents the first preclinical study to identify the synergy of RT and CAR-NK cell therapy in solid tumors and is the first demonstration of CAR-NK cell activity against human HNSCCs. We show significantly enhanced potency of CAR-NK cells against irradiated tumor cells in vitro. Collectively, this research will be vital to guide efforts expanding into other target antigens and tumor types.

Coculture of Human Dendritic and T Cells for the Study of Specific T Cell-Mediated Responses Against Food Allergens.

Dendritic cells (DCs) connect innate and adaptive immunity by sampling, capturing, processing, and presenting the allergen to distinct subsets of CD4+ T cells. In food allergy, this process leads to the generation of allergen-specific Th2 responses and the production of type 2 cytokines that ultimately induce the synthesis of IgE by allergen-specific B cells. In this chapter, we have described different protocols for the isolation of circulating DCs as well as the generation of DC-like cells derived from autologous peripheral monocytes and the human monocytic THP-1 cell line. Coculture of isolated/generated DCs with CD4+ T cells obtained from PBMCs of allergic subjects allows the study of antigen-specific T cell immune responses against food allergens. Early responses upon allergen recognition can be determined by the upregulation of activation markers such as CD154 (CD40 ligand) and the detection of type 2 cytokines (IL-4, IL-5, IL-9, and IL-13). Delayed allergen-specific CD4+ T cell responses induce the proliferation of these cells and the accumulation of type 2 cytokines in coculture supernatants that can be quantified by different approaches (ELISA, EllaTM, and multiplex assays). Together, the protocols described in this chapter can be used to investigate the features of food proteins to induce food allergy, the influence of environmental factors to generate Th2-polarization, the function of DCs to generate differential immune responses in allergic versus tolerant individuals, and to assess the immunomodulating properties of potential therapeutic substances.

Serum cytokine profiles in myasthenia gravis with anti-muscle-specific kinase antibodies

This study measured the serum levels of of 15 cytokines in 15 patients with anti-muscle-specific kinase antibody-positive MG (MuSK-MG) using a multiplex suspension array system. Fifteen patients with non-inflammatory neurological diseases served as controls. Compared with controls, patients with MuSK-MG showed higher levels of Th1- (IFN-γ), Th2- (IL-25, IL-31, and IL-33), Th17- (IL-22), Treg-related cytokines (IL-10), and soluble CD40 ligand (sCD40L). Higher serum Th2-related cytokines (IL-25 and IL-31) levels were correlated with less MG Foundation of America (MGFA) class. These suggest that Th2-related cytokines have protective effects, whereas sCD40L and others may facilitate the disease.

CD40-CD40 ligand interaction between periodontal ligament cells and cementoblasts enhances periodontal tissue remodeling in response to mechanical stress.

We analyzed the localization and expression of Cluster of differentiation 40 ligand (CD40L) in murine periodontal tissue applied with the orthodontic force to determine the CD40L-expressing cells under mechanical stress. Furthermore, we investigated whether CD40-CD40L interaction played an important role in transducing mechanical stress between periodontal ligament (PDL) cells and cementoblasts and remodeling the periodontal tissue for its homeostasis. PDL is a complex tissue that contains heterogeneous cell populations and is constantly exposed to mechanical stress, such as occlusal force. CD40 is expressed on PDL cells and upregulated under mechanical stress. However, whether its ligand, CD40L, is upregulated in periodontal tissue in response to mechanical stress, and which functions the CD40-CD40L interaction induces by converting the force to biological functions between the cement-PDL complex, are not fully understood. The orthodontic treatment was applied to the first molars at the left side of the upper maxillae of mice using a nickel-titanium closed-coil spring. Immunohistochemistry was performed to analyze the localization of CD40L in the periodontal tissue under the orthodontic force. Human cementoblasts (HCEM) and human PDL cells were stretched in vitro and analyzed CD40L and CD40 protein expression using flow cytometry. A GFP-expressing CD40L plasmid vector was transfected into HCEM (CD40L-HCEM). CD40L-HCEM was co-cultured with human PDL cells with higher alkaline phosphatase (ALP) activity (hPDS) or lower ALP (hPDF). After co-culturing, cell viability and proliferation were analyzed by propidium iodide (PI) staining and bromodeoxyuridine (BrdU) assay. Furthermore, the mRNA expression of cytodifferentiation- and extracellular matrix (ECM)-related genes was analyzed by real-time PCR. Immunohistochemistry demonstrated that CD40L was induced on the cells present at the cementum surface in periodontal tissue at the tension side under the orthodontic treatment in mice. The flow cytometry showed that the in vitro-stretching force upregulated CD40L protein expression on HCEM and CD40 protein expression on human PDL cells. Co-culturing CD40L-HCEM with hPDF enhanced cell viability and proliferation but did not alter the gene expression related to cytodifferentiation and ECM. In contrast, co-culturing CD40L-HCEM with hPDS upregulated cytodifferentiation- and ECM-related genes but did not affect cell viability and proliferation. We revealed that in response to a stretching force, CD40L expression was induced on cementoblasts. CD40L on cementoblasts may interact with CD40 on heterogeneous PDL cells at the necessary time and location, inducing cell viability, proliferation, and cytodifferentiation, maintaining periodontal tissue remodeling and homeostasis.