T cell-specific siRNA delivery suppresses HIV-1 infection in humanized mice.

Evaluation of the therapeutic potential of RNAi for HIV infection has been hampered by the challenges of siRNA delivery and lack of suitable animal models. Using a delivery method for T cells, we show that siRNA treatment can dramatically suppress HIV infection. A CD7-specific single-chain antibody was conjugated to oligo-9-arginine peptide (scFvCD7-9R) for T cell-specific siRNA delivery in NOD/SCIDIL2rgamma-/- mice reconstituted with human lymphocytes (Hu-PBL) or CD34+ hematopoietic stem cells (Hu-HSC). In HIV-infected Hu-PBL mice, treatment with anti-CCR5 (viral coreceptor) and antiviral siRNAs complexed to scFvCD7-9R controlled viral replication and prevented the disease-associated CD4 T cell loss. This treatment also suppressed endogenous virus and restored CD4 T cell counts in mice reconstituted with HIV+ peripheral blood mononuclear cells. Moreover, scFvCD7-9R could deliver antiviral siRNAs to naive T cells in Hu-HSC mice and effectively suppress viremia in infected mice. Thus, siRNA therapy for HIV infection appears to be feasible in a preclinical animal model.

Dendritic cells regulate high-speed interstitial T cell migration in the lymph node via LFA-1/ICAM-1.

T lymphocytes vigorously migrate within the paracortex of lymph nodes (LNs) in search of cognate Ags that are presented by dendritic cells (DCs). However, the mechanisms that support T cells to exert the highest motility in a densely packed LN microenvironment are not fully understood. Two-photon microscopy using LN tissue slices revealed that LFA-1 and ICAM-1 were required for high-velocity migration (>10 µm/min) with relatively straight movement. Importantly, ICAM-1 expressed by myeloid lineages, most likely DCs, but not stromal cells or lymphocytes, was sufficient to support the high-velocity migration. Visualizing DCs in the LN from CD11c-EYFP mice showed that T cells traveled over thin dendrites and the body of DCs. Interestingly, DCs supported T cell motility in vitro in chemokine- and ICAM-1-dependent manners. Moreover, an acute lymphopenic environment in the LN significantly increased LFA-1 dependency for T cell migration, indicating that lymphocyte density modulates the use of LFA-1. Therefore, our results indicate that LFA-1/ICAM-1-dependent interactions between T cells and DCs play a crucial role not only in supporting firm arrest during Ag recognition but also in facilitating the Ag scanning processes.

DOCK8 is a Cdc42 activator critical for interstitial dendritic cell migration during immune responses.

To migrate efficiently through the interstitium, dendritic cells (DCs) constantly adapt their shape to the given structure of the extracellular matrix and follow the path of least resistance. It is known that this amoeboid migration of DCs requires Cdc42, yet the upstream regulators critical for localization and activation of Cdc42 remain to be determined. Mutations of DOCK8, a member of the atypical guanine nucleotide exchange factor family, causes combined immunodeficiency in humans. In the present study, we show that DOCK8 is a Cdc42-specific guanine nucleotide exchange factor that is critical for interstitial DC migration. By generating the knockout mice, we found that in the absence of DOCK8, DCs failed to accumulate in the lymph node parenchyma for T-cell priming. Although DOCK8-deficient DCs migrated normally on 2-dimensional surfaces, DOCK8 was required for DCs to crawl within 3-dimensional fibrillar networks and to transmigrate through the subcapsular sinus floor. This function of DOCK8 depended on the DHR-2 domain mediating Cdc42 activation. DOCK8 deficiency did not affect global Cdc42 activity. However, Cdc42 activation at the leading edge membrane was impaired in DOCK8-deficient DCs, resulting in a severe defect in amoeboid polarization and migration. Therefore, DOCK8 regulates interstitial DC migration by controlling Cdc42 activity spatially.

Treatment patterns of systemic drug use in Japanese patients with plaque psoriasis: A retrospective chart review.

Plaque psoriasis (PsO) is a chronic immune-mediated inflammatory disease with skin lesions accompanied by an inflammation-related comorbidity risk. The development of various oral drugs and biologics for PsO has provided increasing systemic treatment options for patients with PsO, and the guidance regarding the use of biologics and PsO treatment schemes are widespread in Japan. However, no comprehensive guidelines regarding systemic drug use are available, and the current treatment patterns of systemic drugs for PsO in Japan remain unclear. We conducted a retrospective chart review to clarify the current treatment patterns of systemic drugs for PsO. We enrolled 114 patients who started systemic drugs for PsO between January 2017 and December 2020 at four institutes, with a mean follow-up of 37.2 months. The mean disease duration was 7.8 (standard deviation 9.5) years at the systemic drug initiation. Of all the patients, 78.1% started with oral drugs (phosphodiesterase [PDE] 4 inhibitors 56.1%. calcineurin inhibitors 14.0%. vitamin A derivatives 7.9%), whereas 21.9% started with biologics (interleukin [IL]-17 inhibitors 9.6%. tumor necrosis factor inhibitors 7.0%. IL-23 inhibitors 3.5%. IL-12/23 inhibitors 1.8%). Oral drugs had shorter drug persistence than biologics: the 12-month persistence of the oral drugs vitamin A derivative, calcineurin inhibitor, and PDE4 inhibitor, was 35.5%, 25.8%, and 60.1%, respectively, compared with that of the biologics IL-23 and IL-17 inhibitors, which was 85.6% and 84.7%, respectively. During the study period, the incidence of treatment changes was 59.1/100 patient-years. Lack of efficacy was the most common reason for treatment changes from monotherapy (34.1%). This retrospective medical chart review allowed us to understand the real-world, long-term treatment patterns of systemic drugs for PsO and the relationships between the reasons for treatment changes and subsequent treatment selection, indicating that there is still room for improvement in the appropriate use of systemic drugs for PsO in Japan.

A discrete choice experiment on oral and injection treatment preferences among moderate-to-severe psoriasis patients in Japan.

Long-term psoriasis (PsO) management remains challenging. With growing variation in treatment efficacy, cost, and modes of administration, patient preferences for different treatment characteristics are not well understood. A discrete choice experiment (DCE), informed by qualitative patient interviews, was conducted to assess patient preferences for different attributes of PsO treatments; 222 adult patients with moderate-to-severe PsO receiving systemic therapy participated in the DCE web survey. Better long-term efficacy and lower cost were preferred (preference weights p < 0.05). Long-term efficacy had the highest relative importance (RI) and mode of administration was as important as the outcome attributes (efficacy and safety). Patients also preferred oral to injectable administration. In subgroup analyses by disease severity, residence, psoriatic arthritis as a comorbidity, and gender, the trends for each subgroup were the same as the overall population although the extent of RI for administration mode varied. Mode of administration was more important for patients with moderate versus severe disease, or rural versus urban residence. This DCE utilized attributes related to both oral and injectable treatment as well as a broad study population of systemic treatment users. Preferences were further stratified by patient characteristics to explore trends in different subgroups. Understanding the RI of treatment attributes and the attribute trade-offs acceptable to patients helps inform moderate-to-severe PsO systemic treatments decisions.

Treatment patterns, healthcare resource utilization, and costs in patients with moderate-to-severe psoriasis treated with systemic therapy in Japan: A retrospective claims database study.

The real-world treatment landscape for patients with moderate-to-severe psoriasis receiving systemic therapies in Japan is not well understood. This study describes the demographic and clinical characteristics, treatment patterns, healthcare resource utilization, and psoriasis-associated costs in these patients. This retrospective observational study used data from the Japan Medical Data Center database between January 2016 and December 2020. Eligible patients had a confirmed diagnosis of psoriasis, ≥1 claim for a systemic treatment of interest, medical history for ≥6 months, and follow-up data for ≥12 months. Systemic therapies comprised biologics (tumor necrosis factor and interleukin inhibitors) and oral treatments (a phosphodiesterase-4 inhibitor, immunosuppressants, and vitamin A). Patient demographics and clinical characteristics, treatment patterns, healthcare resource utilization, and costs were evaluated. The study identified 1770 patients satisfying all inclusion criteria. The mean age was 49.0 years, with 68% of patients aged 20-54 years. Overall, 90.6% and 9.4% of patients received oral medications and biologics as index treatment, respectively. Treatment patterns, healthcare resource utilization, and costs were assessed for treatments received by ≥20 patients (n = 1730). During the 12-month follow-up period, 1102/1730 patients (63.7%) discontinued index treatment, of whom 9.9% switched to alternative systemic treatments. The persistence rate was ≥70% for most biologics and <50% for oral systemic treatments. All 1730 patients had ≥1 all-cause outpatient visit (2.0 visits per person per month) and hospitalization frequency was ≤0.01 per person per month. Persistent patients incurred inflation-adjusted costs of Japanese Yen (JPY) 88 667 per person per month. Treatment switching was associated with an increase in total cost: JPY 128 039 per person per month after switching versus JPY 117 504 before switching. This study of Japanese patients with moderate-to-severe psoriasis demonstrated low persistence, high discontinuation, and low rates of treatment switching with systemic therapies. Switching was associated with increased total cost. These results indicate unmet needs for new treatments.

RNAi-mediated CCR5 silencing by LFA-1-targeted nanoparticles prevents HIV infection in BLT mice.

RNA interference (RNAi)-mediated knockdown of gene expression offers a novel treatment strategy for human immunodeficiency virus (HIV) infection. However, the major hurdle for clinical use is a practical strategy for small interfering RNA (siRNA) delivery to the multiple immune cell types important in viral pathogenesis. We have developed a novel immunoliposome method targeting the lymphocyte function-associated antigen-1 (LFA-1) integrin expressed on all leukocytes and evaluated it for systemic delivery of siRNA in a humanized mouse model. We show that in vivo administration of the LFA-1 integrin-targeted and stabilized nanoparticles (LFA-1 I-tsNPs) results in selective uptake of siRNA by T cells and macrophages, the prime targets of HIV. Further, in vivo administration of anti-CCR5 siRNA/LFA-1 I-tsNPs resulted in leukocyte-specific gene silencing that was sustained for 10 days. Finally, humanized mice challenged with HIV after anti-CCR5 siRNA treatment showed enhanced resistance to infection as assessed by the reduction in plasma viral load and disease-associated CD4 T-cell loss. This study demonstrates the potential in vivo applicability of LFA-1-directed siRNA delivery as anti-HIV prophylaxis.

TNF-alpha is crucial for the development of autoimmune arthritis in IL-1 receptor antagonist-deficient mice.

IL-1 receptor antagonist-deficient (IL-1Ra(-/-)) mice spontaneously develop autoimmune arthritis. We demonstrate here that T cells are required for the induction of arthritis; T cell-deficient IL-1Ra(-/-) mice did not develop arthritis, and transfer of IL-1Ra(-/-) T cells induced arthritis in nu/nu mice. Development of arthritis was also markedly suppressed by TNF-alpha deficiency. We found that TNF-alpha induced OX40 expression on T cells and blocking the interaction between either CD40 and its ligand or OX40 and its ligand suppressed development of arthritis. These findings suggest that IL-1 receptor antagonist deficiency in T cells disrupts homeostasis of the immune system and that TNF-alpha plays an important role in activating T cells through induction of OX40.

Combination effect of mycophenolate mofetil with mizoribine on cell proliferation assays and in a mouse heart transplantation model.

BACKGROUND: Mycophenolate mofetil (MMF) is a highly potent immunosuppressant that suppresses the proliferation of T and B cells by the uncompetitive inhibition of inosine monophosphate dehydrogenase (IMPDH). Consequently, under MMF immunosuppression, good graft survival has been achieved in clinical organ transplantation, although MMF shows adverse gastrointestinal effects. Mizoribine (MZ) also inhibits IMPDH in a competitive manner and is used clinically for organ transplantation in Japan as an immunosuppressant with fewer adverse gastrointestinal effects. Therefore, in this study we investigated the synergistic effects on in vitro and in vivo assays of mice of a combination of MMF with MZ immunosuppression. METHODS: Mixed lymphocyte reaction (MLR) assay and a mouse heart transplantation model were used to evaluate the immunosuppressive effect of MMF with MZ. The median-effect principle and a combination index (CI) were employed to determine synergism, an additive effect, or antagonism. RESULTS: Combination of MMF with MZ resulted in mild synergistic effects in the inhibition of MLR (CI = 0.854-1.143). In the mouse heart transplantation model, C57BL/6 recipients who received a BALB/c heart under the combination of MMF and MZ at 40 + 40 or 80 + 80 mg/kg/day showed a strong synergistic prolongation of graft survival with 19.7 +/- 18.9 (P = 0.0012, CI = 0.438) and 78.4 +/- 36.9 days (P = 0.0002, CI = 0.317), respectively, compared with recipients treated with MMF or MZ monotherapy. CONCLUSIONS.: The combination of MMF and MZ showed mild synergistic effects in the inhibition of MLR and strong synergistic effects in a mouse heart transplantation model.

Mechanism of allorecognition and skin graft rejection in CD28 and CD40 ligand double-deficient mice.

BACKGROUND: It has been shown that simultaneous blockade of CD28- and CD40-mediated costimulatory signals significantly prolongs allograft survival. Although these results led to an expectation of the establishment of specific immunotolerant therapy for organ transplantation, it became evident that these treatments rarely resulted in indefinite allograft survival. To uncover the mechanisms underlying these costimulation blockade-resistant allograft rejections, we studied the process of allogenic skin graft rejection in CD28 and CD40 ligand (L) double-deficient (double-knockout [dKO]) mice. METHODS: Skin grafts from BALB/c or BALB.B mice were transplanted to C57BL/6 background dKO mice. The frequency of CD4+ and CD8+ T cells responding to alloantigens presented by direct or indirect pathways were defined by the use of a cytostaining assay. RESULTS: BALB/c skin grafts were rapidly rejected by dKO mice. This CD28 and CD40L independent allograft rejection was inhibited by the depletion of CD8+ T cells. In vitro studies indicated that CD8+ T cells from BALB/c skin-grafted dKO mice responded to donor antigen presented only by the direct pathway. Unlike major histocompatibility complex (MHC)-mismatched donors, allogenic skin grafts from MHC-matched donors were accepted by dKO mice. CONCLUSION: In the absence of CD28 and CD40 costimulatory signals, CD8+ T cells recognize MHC antigens by the direct pathway, resulting in the rejection of skin grafts from MHC-mismatched donors. In contrast, MHC-matched and non-MHC-mismatched donor skin grafts indefinitely survive in dKO mice. These results indicated that donor-host MHC matching may still be critical to costimulation blockade therapy for organ transplantation.

Mst1 regulates integrin-dependent thymocyte trafficking and antigen recognition in the thymus.

Thymocyte trafficking has an important role in thymic selection. Here we show that the Hippo homologue Mst1 is required for thymocyte migration and antigen recognition by LFA-1 and ICAM-1 within the medulla. Using two-photon imaging of thymic tissues, we found that highly motile mature thymocytes arrest and are activated in the vicinity of rare populations of Aire(+) ICAM-1(hi) medullary thymic epithelia in a negatively selecting environment. Notably, Mst1 deficiency or blocking the cell adhesion molecules LFA-1 and ICAM-1 results in inefficient migration and antigen recognition of CD4(+) thymocytes within the medulla. Consistent with these defects, thymocyte selection is impaired in Mst1(-/-) mice, which display T cell-dependent inflammatory infiltrates in multiple organs and develop autoantibodies. Our results suggest that Mst1 has a key role in regulating thymocyte self-antigen recognition in the medulla.

Antigen-specific human T-cell responses and T cell-dependent production of human antibodies in a humanized mouse model.

Humanized mice with a functional human immune system would be very useful for in vivo studies of human immunobiology. We have previously shown that cotransplantation of human fetal thymus/liver tissues and CD34(+) fetal liver cells into immunodeficient nonobese diabetic severe combined immunodeficiency (NOD/SCID) mice leads to the development of multiple lineages of human lymphohematopoietic cells and formation of secondary lymphoid organs with normal architecture. Here, we evaluated the ability of these humanized mice to develop antigen-specific, T cell-dependent antibody responses after in vivo immunization with T-dependent antigen, 2,4-dinitrophenyl hapten-keyhole limpet hemocyanin (DNP(23)-KLH). Human T cells from DNP(23)-KLH-immunized mice showed strong proliferation in response to KLH in vitro. Furthermore, T cell-dependent production of DNP-specific human antibodies (mainly IgG1 and IgG2) was detected in all immunized mice. These results confirm that a functional human immune system can be established in immunodeficient mice through cotransplantation of human fetal thymus/liver tissues and CD34(+) hematopoietic stem/progenitor cells.

CD28-dependent differentiation into the effector/memory phenotype is essential for induction of arthritis in interleukin-1 receptor antagonist-deficient mice.

OBJECTIVE: Interleukin-1 receptor antagonist (IL-1Ra)-deficient mice on a BALB/c background spontaneously develop a chronic inflammatory polyarthropathy closely resembling that of rheumatoid arthritis in humans. To elucidate the role of CD28 costimulatory signals in the development of this disease, we studied IL-1Ra/CD28-double-deficient mice. METHODS: We crossed IL-1Ra-deficient mice with CD28-deficient mice and observed the incidence and severity of arthritis. To investigate functions of IL-1Ra/CD28-double-deficient T cells, cells were stimulated with CD3 monoclonal antibody or allogeneic antigen-presenting cells (APCs) and their proliferative responses and levels of cytokine production were measured. RESULTS: Disease severity was lower in IL-1Ra/CD28-double-deficient mice than in mice that were deficient only in IL-1Ra, although incidence of arthritis was not affected by the presence or absence of CD28. When pathogenic IL-1Ra-KO T cells were transferred into nude mice, severe arthritis developed. Even though T cells from double-deficient mice showed the same diminished proliferative capacity as was seen in T cells from CD28-single-deficient animals, nude mice into which double-deficient T cells were transferred never developed arthritis. CONCLUSION: These findings indicate that IL-1Ra/CD28-double-deficient T cells can be activated by IL-1Ra-deficient activated APCs, resulting in induction of arthritis; however, these T cells did not induce the disease under normal conditions, because they did not differentiate into effector/memory phenotype.

Effect of inflammation on costimulation blockade-resistant allograft rejection.

Previously, we reported that allogeneic skin grafts were rapidly rejected by CD28 and CD40 ligand double deficient mice mediated by CD8+ T cells. These results indicated that some elements in addition to CD28- and CD40-mediated costimulation provide stimulatory signals for the activation of donor-specific CD8+ T cells. In this report, we investigated the role of inflammation associated with transplantation on costimulation-independent priming of CD8+ T cell during graft rejection. B6 RAG1 KO mice were transplanted with BALB/c-skin and adoptively transferred with syngeneic CD8+ T cells the same day or 50 days after transplantation. When blockade of CD28- and CD40-mediated costimulation failed to prevent acute rejection of freshly transplanted skin grafts, it efficiently delayed rejection of well-healed skin grafts. These results showed that factors associated with transplantation have essential roles in inducing costimulation blockade-resistant allograft rejection. Costimulation blockade failed to prevent acute graft-infiltration of NK cells and increasing expression of intragraft IL-12 and IL-15. These factors may trigger the graft-infiltration and priming of CD8+ T cells to induce costimulation blockade-resistant allograft rejection.

Effects of double blockade of CD28 and inducible-costimulator signaling on anti-glomerular basement membrane glomerulonephritis.

Inducible costimulator (ICOS) is the third member of the CD28 superfamily, expressed on antigen-primed T-cells, enhancing Th2 differentiation. Anti-glomerular basement membrane (anti-GBM) glomerulonephritis results from multiple effects generated by both Th1 and Th2 cells. To evaluate the contribution of these T-cells to the progression of anti-GBM glomerulonephritis, we investigated the effect of double blockade of CD28 and ICOS signaling. Anti-GBM glomerulonephritis was induced in C57BL/6 mice, a Th1-prone strain. CD28 signaling was inhibited with the use of fusion proteins of cytolytic T-lymphocyte-associated antigen-4 (CTLA4 immunoglobulin) and ICOS signaling by the monoclonal antibody (mAb) for ICOS. Blood and urine samples were collected 5 and 14 days after induction of anti-GBM glomerulonephritis. Mice were killed to facilitate histopathologic analyses at the same time. Anti-GBM glomerulonephritis was prevented from functionally deteriorating (eg, proteinuria or increasing serum creatinine) by CTLA4 immunoglobulin or anti-activation-inducible lymphocyte immunomodulatory molecule (AILIM) mAb as an anti-ICOS mAb. Nevertheless, double or single blockade of ICOS signaling showed a weaker inhibitory effect than single blockade of CD28 signaling in terms of the serum immunoglobulin level and histopathologic change. There is no synergistic effect between CTLA4 immunoglobulin and anti-AILIM mAb when simultaneously administered in experimental anti-GBM glomerulonephritis. Double blockade of both CD28 signaling and ICOS signaling is effective for preventing functional deterioration in this model. However, CD28 single blockade is more effective than double blockade both serologically and histopathologically.