Neovascular retinopathies are major causes of vision loss; yet treatments to prevent the condition are inadequate. The role of regulatory T cells in neovascular retinopathy is unknown. Here we show ...that in retinopathy regulatory T cells are transiently increased in lymphoid organs and the retina, but decline when neovascularization is established. The decline is prevented following regulatory T cells expansion with an IL-2/anti-IL-2 mAb complex or the adoptive transfer of regulatory T cells. Further, both approaches reduce vasculopathy (vaso-obliteration, neovascularization, vascular leakage) and alter the activation of Tmem119
retinal microglia. Our in vitro studies complement these findings, showing that retinal microglia co-cultured with regulatory T cells exhibit a reduction in co-stimulatory molecules and pro-inflammatory mediators that is attenuated by CTLA-4 blockade. Collectively, we demonstrate that regulatory T cells are recruited to the retina and, when expanded in number, repair the vasculature. Manipulation of regulatory T cell numbers is a previously unrecognized, and promising avenue for therapies to prevent blinding neovascular retinopathies.The local immune responses in the eye are attenuated to preserve sight. Surprisingly, Deliyanti et al. show that regulatory T cells (Tregs) take an active role in protecting the eye from neovascularization in oxygen-induced retinopathy, and that interventions that augment the retinal Treg numbers reduce neovascular retinopathy in mice.
Therapies to reduce liver fibrosis and stimulate organ regeneration are urgently needed. We conducted a first-in-human, phase 1 dose-escalation trial of autologous macrophage therapy in nine adults ...with cirrhosis and a Model for End-Stage Liver Disease (MELD) score of 10-16 (ISRCTN 10368050). Groups of three participants received a single peripheral infusion of 10
, 10
or up to 10
cells. Leukapheresis and macrophage infusion were well tolerated with no transfusion reactions, dose-limiting toxicities or macrophage activation syndrome. All participants were alive and transplant-free at one year, with only one clinical event recorded, the occurrence of minimal ascites. The primary outcomes of safety and feasibility were met. This study informs and provides a rationale for efficacy studies in cirrhosis and other fibrotic diseases.
Limbal stem cell deficiency (LSCD) is a disease resulting from the loss or dysfunction of epithelial stem cells, which seriously impairs sight. Autologous limbal stem cell transplantation is ...effective in unilateral or partial bilateral disease but not applicable in total bilateral disease. An allogeneic source of transplantable cells for use in total bilateral disease can be obtained from culture of donated cadaveric corneal tissue. We performed a controlled multicenter study to examine the feasibility, safety, and efficacy of allogeneic corneal epithelial stem cells in the treatment of bilateral LSCD. Patients were randomized to receive corneal epithelial stem cells cultured on amniotic membrane (AM): investigational medicinal product (IMP) or control AM only. Patients received systemic immunosuppression. Primary endpoints were safety and visual acuity, secondary endpoint was change in composite ocular surface score (OSS). Sixteen patients were treated and 13 patients completed all assessments. Safety was demonstrated and 9/13 patients had improved visual acuity scores at the end of the trial, with no significant differences between IMP and control groups. Patients in the IMP arm demonstrated significant, sustained improvement in OSS, whereas those in the control arm did not. Serum cytokine levels were measured during and after the period of immune suppression and we identified strongly elevated levels of CXCL8 in the serum of patients with aniridia, which persisted throughout the trial. This first randomized control trial of allogeneic corneal epithelial stem cells in severe bilateral LSCD demonstrates the feasibility and safety of this approach. Stem Cells Translational Medicine 2019;8:323–331
Patients with severe ocular surface disorder received transplants of amniotic membrane with (black bars) or without (gray bars) cadaveric‐donor‐derived cultured limbal stem cells. All patients received immune suppression. Only patients who received transplants containing limbal stem cells showed sustained significant improvements (reductions) in combined ocular surface scores (5 factors scored 0–3 where 0 is a normal eye score).
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Epstein-Barr virus associated lymphoproliferative disease is a serious complication of immunosuppression, particularly after transplantation. Initial treatments usually comprise reduction of ...immunosuppression, rituximab and/or chemotherapy. However, some patients fail to respond or are unsuitable for chemotherapy and so are candidates for adoptive cellular therapy. Here we report outcomes from the use of a bank of 25 third party derived Epstein-Barr virus specific lymphocyte cell lines cryopreserved for immediate use, issued on a best-HLA match basis. Cells have been issued to 70 patients. The infusions were well tolerated, although in two patients, evidence of mild, transient, cutaneous GVHD was observed, both treated with topical agents. In one patient, there was a temporary worsening of neurological symptoms, thought to represent a tumour flare in a patient who responded. 59 patients have received cells with a follow up of >6 months, 34 (58%) male and 25 (42%) female. The median age was 31 years (range 1 - 82). 48 patients had received transplants, 28 HSCT and 20 solid organs. All HSCT patients had received transplants from unrelated donors. SOT types were as follows: kidney, 10; liver, 3; heart, 2; bowel, 1; liver, small bowel and pancreas, 1; combined liver and kidney, 1; combined kidney and pancreas, 1; heart and kidney, 1. Eleven patients were immune suppressed due to causes other than transplantation: five with congenital immunodeficiencies, two on maintenance for acute lymphoblastic leukemia and two on immunosuppressive drugs (1 Crohn disease and 1 Systemic Lupus Erythematosus). One patient had EBV positive natural killer/T cell lymphoma and one diffuse large B cell lymphoma of the elderly.
Responses were observed in 35/59 (59%) patients, with rates being highest (75%) post-solid organ transplantation, intermediate (64%) in non-transplant cases and lowest (46%) after hematopoietic stem cell transplantation (p=0.13, Fisher exact). Although most patients were treated after more conventional therapies had failed or were deemed inappropriate, 39% were alive at time of census. Overall survivals were only somewhat less than response rates after solid organ transplantation (60%) and in non-transplant (54%) patients, but worse (18%) after hematopoietic stem cell transplantation (p=0.007, logrank). The mean survival was 2.3 years (95% CI 1.6 - 3.0) and median survival 0.7 years (95%CI 0.0 - 1.8y). Survivals were higher in patients who had not had a transplant or after undergoing SOT versus HSCT, and this difference was statistically significant (p=0.007; log rank). Outcomes were notably good for solitary central nervous system lesions with 12/13 responses (p=0.012, Fisher exact). At census, 132 HLA matching requests have been processed and 61 allocation reviews completed. The median number of class I matches was 3 (range 0-6) and class II matches 2 (range 0-4). The median number of class I+II matches was 4.5 (range 0-9). For CTLs issued the median number of class I matches was 3 (range 1-6) and class II matches 2 (range 0-4). The median number of class I+II matches was 5 (range 2-9). Response rates were moderately higher using better HLA-matched lymphocytes, although this only reached statistical significance (p=0.043) if a one tailed linear-by-linear association test was used. Despite the license covering all European Union countries, locations of recipients were biased towards the United Kingdom (58/64). These data support the use of third party derived cytotoxic lymphocytes in this difficult to treat group of patients, although their current use after hematopoietic stem cell transplantation remains to be optimized.
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Kazi:Shire: Other: Vonvendi was provided by Shire. Vickers:GSK: Equity Ownership; University of Aberdeen: Patents & Royalties.
Macrophages elicit immune responses to pathogens through induction of inflammatory genes. Here, we examined the role of three variants of the SWI/SNF nucleosome remodeling complex—cBAF, ncBAF, and ...PBAF—in the macrophage response to bacterial endotoxin (lipid A). All three SWI/SNF variants were prebound in macrophages and retargeted to genomic sites undergoing changes in chromatin accessibility following stimulation. Cooperative binding of all three variants associated with de novo chromatin opening and latent enhancer activation. Isolated binding of ncBAF and PBAF, in contrast, associated with activation and repression of active enhancers, respectively. Chemical and genetic perturbations of variant-specific subunits revealed pathway-specific regulation in the activation of lipid A response genes, corresponding to requirement for cBAF and ncBAF in inflammatory and interferon-stimulated gene (ISG) activation, respectively, consistent with differential engagement of SWI/SNF variants by signal-responsive transcription factors. Thus, functional diversity among SWI/SNF variants enables increased regulatory control of innate immune transcriptional programs, with potential for specific therapeutic targeting.
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•Inflammatory stimulation induces changes in chromatin accessibility•SWI/SNF complex variants are cooperatively recruited to de novo enhancers•Functional diversity among SWI/SNF variants instructs inflammatory response•SWI/SNF inhibition disrupts de novo enhancer activation and induced gene expression
Chromatin accessibility shapes the transcriptional response to stimulation. Liao et al. show that cooperative binding of SWI/SNF complexes mediates basal and induced accessibility in macrophages in response to inflammatory stimulation. Chemical SWI/SNF inhibition reveals functional diversity among SWI/SNF variants, which ensures proper inflammatory gene expression.
Summary Purpose To identify focal lesions of elevated MRI T2 and T1ρ relaxation times in articular cartilage of an ACL-injured group using a novel cluster analysis technique. Materials and methods ...Eighteen ACL-injured patients underwent 3T MRI T2 and T1ρ relaxometry at baseline, six months and one year and six healthy volunteers at baseline, one day and one year. Clusters of contiguous pixels above or below T2 and T1ρ intensity and area thresholds were identified on a projection map of the 3D femoral cartilage surface. The total area of femoral cartilage plate covered by clusters (%CA) was split into areas above (%CA+) and below (%CA-) the thresholds and the differences in %CA(+or -) over time in the ACL-injured group were determined using the Wilcoxon signed rank test. Results %CA+ was greater in the ACL-injured patients than the healthy volunteers at six months and one year with average %CA+ of 5.2 ± 4.0% (p=0.0054) and 6.6 ± 3.7% (p=0.0041) for T2 and 6.2 ± 7.1% (p = 0.063) and 8.2 ± 6.9% (p = 0.042) for T1ρ , respectively. %CA-at six months and one year was 3.0 ± 1.8% (p > 0.1) and 5.9 ± 5.0% (p > 0.1) for T2 and 4.4 ± 4.9% (p > 0.1) and 4.5 ± 4.6% (p > 0.1) for T1ρ , respectively. Conclusion With the proposed cluster analysis technique, we have quantified cartilage lesion coverage and demonstrated that the ACL-injured group had greater areas of elevated T2 and T1ρ relaxation times as compared to healthy volunteers.
Recent exon-sequencing studies of human tumours have revealed that subunits of BAF (mammalian SWI/SNF) complexes are mutated in more than 20% of all human malignancies, but the mechanisms involved in ...tumour suppression are unclear. BAF chromatin-remodelling complexes are polymorphic assemblies that use energy provided by ATP hydrolysis to regulate transcription through the control of chromatin structure and the placement of Polycomb repressive complex 2 (PRC2) across the genome. Several proteins dedicated to this multisubunit complex, including BRG1 (also known as SMARCA4) and BAF250a (also known as ARID1A), are mutated at frequencies similar to those of recognized tumour suppressors. In particular, the core ATPase BRG1 is mutated in 5-10% of childhood medulloblastomas and more than 15% of Burkitt's lymphomas. Here we show a previously unknown function of BAF complexes in decatenating newly replicated sister chromatids, a requirement for proper chromosome segregation during mitosis. We find that deletion of Brg1 in mouse cells, as well as the expression of BRG1 point mutants identified in human tumours, leads to anaphase bridge formation (in which sister chromatids are linked by catenated strands of DNA) and a G2/M-phase block characteristic of the decatenation checkpoint. Endogenous BAF complexes interact directly with endogenous topoisomerase IIα (TOP2A) through BAF250a and are required for the binding of TOP2A to approximately 12,000 sites across the genome. Our results demonstrate that TOP2A chromatin binding is dependent on the ATPase activity of BRG1, which is compromised in oncogenic BRG1 mutants. These studies indicate that the ability of TOP2A to prevent DNA entanglement at mitosis requires BAF complexes and suggest that this activity contributes to the role of BAF subunits as tumour suppressors.
The persistence of a pool of latently HIV-1-infected cells despite combination anti-retroviral therapy treatment is the major roadblock for a cure. The BAF (mammalian SWI/SNF) chromatin remodeling ...complex is involved in establishing and maintaining viral latency, making it an attractive drug target for HIV-1 latency reversal. Here we report a high-throughput screen for inhibitors of BAF-mediated transcription in cells and the subsequent identification of a 12-membered macrolactam. This compound binds ARID1A-specific BAF complexes, prevents nucleosomal positioning, and relieves transcriptional repression of HIV-1. Through this mechanism, these compounds are able to reverse HIV-1 latency in an in vitro T cell line, an ex vivo primary cell model of HIV-1 latency, and in patient CD4+ T cells without toxicity or T cell activation. These macrolactams represent a class of latency reversal agents with unique mechanism of action, and can be combined with other latency reversal agents to improve reservoir targeting.
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•HTS identifies a macrolactam that inhibits BAF transcriptional repression•The macrolactams are likely targeting specific ARID1A-containing BAF complexes•The macrolactams reverse HIV-1 latency and are non-toxic to T cells•The macrolactams can be combined with other latency reversal agents
The BAF (SWI/SNF) chromatin remodeling complex is involved in repressing HIV-1 transcription in latently infected T cells. Using high-throughput screening, we identified a macrolactam that inhibits ARID1A-containing BAF complexes to reverse HIV-1 latency without T cell activation or toxicity.
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