Benserazide racemate and enantiomers induce fetal globin gene expression in vivo: Studies to guide clinical development for beta thalassemia and sickle cell disease.

Increased expression of developmentally silenced fetal globin (HBG) reduces the clinical severity of ß-hemoglobinopathies. Benserazide has a relatively benign safety profile having been approved for 50 years in Europe and Canada for Parkinson's disease treatment. Benserazide was shown to activate HBG gene transcription in a high throughput screen, and subsequent studies confirmed fetal hemoglobin (HbF) induction in erythroid progenitors from hemoglobinopathy patients, transgenic mice containing the entire human ß-globin gene (ß-YAC) and anemic baboons. The goal of this study is to evaluate efficacies and plasma exposure profiles of benserazide racemate and its enantiomers to select the chemical form for clinical development. Intermittent treatment with all forms of benserazide in ß-YAC mice significantly increased proportions of red blood cells expressing HbF and HbF protein per cell with similar pharmacokinetic profiles and with no cytopenia. These data contribute to the regulatory justification for development of the benserazide racemate. Additionally, dose ranges and frequencies required for HbF induction using racemic benserazide were explored. Orally administered escalating doses of benserazide in an anemic baboon induced γ-globin mRNA up to 13-fold and establish an intermittent dose regimen for clinical studies as a therapeutic candidate for potential treatment of ß-hemoglobinopathies.

Dimethyl fumarate increases fetal hemoglobin, provides heme detoxification, and corrects anemia in sickle cell disease.

Sickle cell disease (SCD) results from a point mutation in the ß-globin gene forming hemoglobin S (HbS), which polymerizes in deoxygenated erythrocytes, triggering recurrent painful vaso-occlusive crises and chronic hemolytic anemia. Reactivation of fetal Hb (HbF) expression ameliorates these symptoms of SCD. Nuclear factor (erythroid derived-2)-like 2 (Nrf2) is a transcription factor that triggers cytoprotective and antioxidant pathways to limit oxidative damage and inflammation and increases HbF synthesis in CD34+ stem cell-derived erythroid progenitors. We investigated the ability of dimethyl fumarate (DMF), a small-molecule Nrf2 agonist, to activate γ-globin transcription and enhance HbF in tissue culture and in murine and primate models. DMF recruited Nrf2 to the γ-globin promoters and the locus control region of the ß-globin locus in erythroleukemia cells, elevated HbF in SCD donor-derived erythroid progenitors, and reduced hypoxia-induced sickling. Chronic DMF administration in SCD mice induced HbF and increased Nrf2-dependent genes to detoxify heme and limit inflammation. This improved hematological parameters, reduced plasma-free Hb, and attenuated inflammatory markers. Chronic DMF administration to nonanemic primates increased γ-globin mRNA in BM and HbF protein in rbc. DMF represents a potential therapy for SCD to induce HbF and augment vasoprotection and heme detoxification.

Mentored Training to Increase Diversity among Faculty in the Biomedical Sciences: The NHLBI Summer Institute Programs to Increase Diversity (SIPID) and the Programs to Increase Diversity among Individuals Engaged in Health-related Research (PRIDE).

OBJECTIVE: To report baseline characteristics of junior-level faculty participants in the Summer Institute Programs to Increase Diversity (SIPID) and the Programs to Increase Diversity among individuals engaged in Health-Related Research (PRIDE), which aim to facilitate participants' career development as independent investigators in heart, lung, blood, and sleep research. DESIGN AND SETTING: Junior faculty from groups underrepresented in the biomedical-research workforce attended two, 2-3 week, annual summer research-education programs at one of six sites. Programs provided didactic and/or laboratory courses, workshops to develop research, writing and career-development skills, as well as a mentoring component, with regular contact maintained via phone, email and webinar conferences. Between summer institutes, trainees participated in a short mid-year meeting and an annual scientific meeting. Participants were surveyed during and after SIPID/PRIDE to evaluate program components. PARTICIPANTS: Junior faculty from underrepresented populations across the United States and Puerto Rico participated in one of three SIPID (2007-2010) or six PRIDE programs (2011-2014). RESULTS: Of 204 SIPID/PRIDE participants, 68% were female; 67% African American and 27% Hispanic/Latino; at enrollment, 75% were assistant professors and 15% instructors, with most (96%) on non-tenure track. Fifty-eight percent had research doctorates (PhD, ScD) and 42% had medical (MD, DO) degrees. Mentees' feedback about the program indicated skills development (eg, manuscript and grant writing), access to networking, and mentoring were the most beneficial elements of SIPID and PRIDE programs. Grant awards shifted from primarily mentored research mechanisms to primarily independent investigator awards after training. CONCLUSIONS: Mentees reported their career development benefited from SIPID and PRIDE participation.

A Perspective on Promoting Diversity in the Biomedical Research Workforce: The National Heart, Lung, and Blood Institute's PRIDE Program.

Aspiring junior investigators from groups underrepresented in the biomedical sciences face various challenges as they pursue research independence. However, the biomedical research enterprise needs their participation to effectively address critical research issues such as health disparities and health inequities. In this article, we share a research education and mentoring initiative that seeks to address this challenge: Programs to Increase Diversity among Individuals Engaged in Health Related Research (PRIDE), funded by the National Heart, Lung, and Blood Institute (NHLBI). This longitudinal research-education and mentoring program occurs through summer institute programs located at US-based academic institutions. Recruited participants are exposed to didactic and lab-based research-skill enhancement experiences, with year-round mentoring over the course of two years. Mentor-mentee matching is based on shared research interests to promote congruence and to enhance skill acquisition. Program descriptions and sample narratives of participants' perceptions of PRIDE's impact on their career progress are showcased. Additionally, we highlight the overall program design and structure of four of seven funded summer institutes that focus on cardiovascular disease, related conditions, and health disparities. Mentees' testimonials about the value of the PRIDE mentoring approach in facilitating career development are also noted. Meeting the clinical and research needs of an increasingly diverse US population is an issue of national concern. The PRIDE initiative, which focuses on increasing research preparedness and professional development of groups underrepresented in the biomedical research workforce, with an emphasis on mentoring as the critical approach, provides a robust model that is impacting the careers of future investigators.

Targeting translation: eIF4E as an emerging anticancer drug target.

The translation initiation factor eIF4E mediates a rate-limiting process that drives selective translation of many oncongenic proteins such as cyclin D1, survivin and VEGF, thereby contributing to tumour growth, metastasis and therapy resistance. As an essential regulatory hub in cancer signalling network, many oncogenic signalling pathways appear to converge on eIF4E. Therefore, targeting eIF4E-mediated cap-dependent translation is considered a promising anticancer strategy. This paper reviews the strategies that can be used to target eIF4E, highlighting agents that target eIF4E activity at each distinct level.

Novel Inducers of Fetal Globin Identified through High Throughput Screening (HTS) Are Active In Vivo in Anemic Baboons and Transgenic Mice.

High-level fetal (γ) globin expression ameliorates clinical severity of the beta (ß) hemoglobinopathies, and safe, orally-bioavailable γ-globin inducing agents would benefit many patients. We adapted a LCR-γ-globin promoter-GFP reporter assay to a high-throughput robotic system to evaluate five diverse chemical libraries for this activity. Multiple structurally- and functionally-diverse compounds were identified which activate the γ-globin gene promoter at nanomolar concentrations, including some therapeutics approved for other conditions. Three candidates with established safety profiles were further evaluated in erythroid progenitors, anemic baboons and transgenic mice, with significant induction of γ-globin expression observed in vivo. A lead candidate, Benserazide, emerged which demonstrated > 20-fold induction of γ-globin mRNA expression in anemic baboons and increased F-cell proportions by 3.5-fold in transgenic mice. Benserazide has been used chronically to inhibit amino acid decarboxylase to enhance plasma levels of L-dopa. These studies confirm the utility of high-throughput screening and identify previously unrecognized fetal globin inducing candidates which can be developed expediently for treatment of hemoglobinopathies.

UFBP1, a Key Component of the Ufm1 Conjugation System, Is Essential for Ufmylation-Mediated Regulation of Erythroid Development.

The Ufm1 conjugation system is an ubiquitin-like modification system that consists of Ufm1, Uba5 (E1), Ufc1 (E2), and less defined E3 ligase(s) and targets. The biological importance of this system is highlighted by its essential role in embryogenesis and erythroid development, but the underlying mechanism is poorly understood. UFBP1 (Ufm1 binding protein 1, also known as DDRGK1, Dashurin and C20orf116) is a putative Ufm1 target, yet its exact physiological function and impact of its ufmylation remain largely undefined. In this study, we report that UFBP1 is indispensable for embryonic development and hematopoiesis. While germ-line deletion of UFBP1 caused defective erythroid development and embryonic lethality, somatic ablation of UFBP1 impaired adult hematopoiesis, resulting in pancytopenia and animal death. At the cellular level, UFBP1 deficiency led to elevated ER (endoplasmic reticulum) stress and activation of unfolded protein response (UPR), and consequently cell death of hematopoietic stem/progenitor cells. In addition, loss of UFBP1 suppressed expression of erythroid transcription factors GATA-1 and KLF1 and blocked erythroid differentiation from CFU-Es (colony forming unit-erythroid) to proerythroblasts. Interestingly, depletion of Uba5, a Ufm1 E1 enzyme, also caused elevation of ER stress and under-expression of erythroid transcription factors in erythroleukemia K562 cells. By contrast, knockdown of ASC1, a newly identified Ufm1 target that functions as a transcriptional co-activator of hormone receptors, led to down-regulation of erythroid transcription factors, but did not elevate basal ER stress. Furthermore, we found that ASC1 was associated with the promoters of GATA-1 and Klf1 in a UFBP1-dependent manner. Taken together, our findings suggest that UFBP1, along with ASC1 and other ufmylation components, play pleiotropic roles in regulation of hematopoietic cell survival and differentiation via modulating ER homeostasis and erythroid lineage-specific gene expression. Modulating the activity of this novel ubiquitin-like system may represent a novel approach to treat blood-related diseases such as anemia.

Cell signaling pathways involved in drug-mediated fetal hemoglobin induction: Strategies to treat sickle cell disease.

The developmental regulation of globin gene expression has shaped research efforts to establish therapeutic modalities for individuals affected with sickle cell disease and ß-thalassemia. Fetal hemoglobin has been shown to block sickle hemoglobin S polymerization to improve symptoms of sickle cell disease; moreover, fetal hemoglobin functions to replace inadequate hemoglobin A synthesis in ß-thalassemia thus serving as an effective therapeutic target. In the perinatal period, fetal hemoglobin is synthesized at high levels followed by a decline to adult levels by one year of age. It is known that naturally occurring mutations in the γ-globin gene promoters and distant cis-acting transcription factors produce persistent fetal hemoglobin synthesis after birth to ameliorate clinical symptoms. Major repressor proteins that silence γ-globin during development have been targeted for gene therapy in ß-hemoglobinopathies patients. In parallel effort, several classes of pharmacological agents that induce fetal hemoglobin expression through molecular and cell signaling mechanisms have been identified. Herein, we reviewed the progress made in the discovery of signaling molecules targeted by pharmacologic agents that enhance γ-globin expression and have the potential for future drug development to treat the ß-hemoglobinopathies.

Monomethylfumarate induces γ-globin expression and fetal hemoglobin production in cultured human retinal pigment epithelial (RPE) and erythroid cells, and in intact retina.

PURPOSE: Sickle retinopathy (SR) is a major cause of vision loss in sickle cell disease (SCD). There are no strategies to prevent SR and treatments are extremely limited. The present study evaluated (1) the retinal pigment epithelial (RPE) cell as a hemoglobin producer and novel cellular target for fetal hemoglobin (HbF) induction, and (2) monomethylfumarate (MMF) as an HbF-inducing therapy and abrogator of oxidative stress and inflammation in SCD retina. METHODS: Human globin gene expression was evaluated by RT-quantitative (q)PCR in the human RPE cell line ARPE-19 and in primary RPE cells isolated from Townes humanized SCD mice. γ-Globin promoter activity was monitored in KU812 stable dual luciferase reporter expressing cells treated with 0 to 1000 µM dimethylfumarate, MMF, or hydroxyurea (HU; positive control) by dual luciferase assay. Reverse transcriptase-qPCR, fluorescence-activated cell sorting (FACS), immunofluorescence, and Western blot techniques were used to evaluate γ-globin expression and HbF production in primary human erythroid progenitors, ARPE-19, and normal hemoglobin producing (HbAA) and homozygous ß(s) mutation (HbSS) RPE that were treated similarly, and in MMF-injected (1000 µM) HbAA and HbSS retinas. Dihydroethidium labeling and nuclear factor (erythroid-derived 2)-like 2 (Nrf2), IL-1ß, and VEGF expression were also analyzed. RESULTS: Retinal pigment epithelial cells express globin genes and synthesize adult and fetal hemoglobin MMF stimulated γ-globin expression and HbF production in cultured RPE and erythroid cells, and in HbSS mouse retina where it also reduced oxidative stress and inflammation. CONCLUSIONS: The production of hemoglobin by RPE suggests the potential involvement of this cell type in the etiology of SR. Monomethylfumarate influences multiple parameters consistent with improved retinal health in SCD and may therefore be of therapeutic potential in SR treatment.

FK228 Analogues Induce Fetal Hemoglobin in Human Erythroid Progenitors.

Fetal hemoglobin (HbF) improves the clinical severity of sickle cell disease (SCD), therefore, research to identify HbF-inducing agents for treatment purposes is desirable. The focus of our study is to investigate the ability of FK228 analogues to induce HbF using a novel KU812 dual-luciferase reporter system. Molecular modeling studies showed that the structure of twenty FK228 analogues with isosteric substitutions did not disturb the global structure of the molecule. Using the dual-luciferase system, a subgroup of FK228 analogues was shown to be inducers of HbF at nanomolar concentrations. To determine the physiological relevance of these compounds, studies in primary erythroid progenitors confirmed that JMA26 and JMA33 activated HbF synthesis at levels comparable to FK228 with low cellular toxicity. These data support our lead compounds as potential therapeutic agents for further development in the treatment of SCD.

The role of indoleamine 2, 3 dioxygenase in regulating host immunity to leishmania infection.

Pathogen persistence in immune-competent hosts represents an immunological paradox. Increasing evidence suggests that some pathogens, such as, Leishmania major (L. major) have evolved strategies and mechanisms that actively suppress host adaptive immunity. If this notion is correct conventional vaccination therapies may be ineffective in enhancing host immunity, unless natural processes that suppress host immunity are also targeted therapeutically. The key problem is that the basis of pathogen persistence in immune-competent individuals is unknown, despite decades of intense research. This fact, coupled with poor health care and a dearth of effective treatments means that these diseases will remain a scourge on humans unless a better understanding of why the immune system tolerates such infections emerges from research. Indoleamine 2,3-dioxygenase (IDO) has been shown to act as a molecular switch regulating host responses, and IDO inhibitor drugs shown to possess potential in enhancing host immunity to established leishmania infections. It is hoped that this review will help stimulate and help generate critical new knowledge pertaining to the IDO mechanism and how to exploit it to suppress T cell mediated immunity, thus offer an innovative approach to studying the basis of chronic leishmania infection in mice.

Leishmania major attenuates host immunity by stimulating local indoleamine 2,3-dioxygenase expression.

Inflammation stimulates immunity but can create immune privilege in some settings. Here, we show that cutaneous Leishmania major infection stimulated expression of the immune regulatory enzyme indoleamine 2,3 dioxygenase (IDO) in local lymph nodes. Induced IDO attenuated the T cell stimulatory functions of dendritic cells and suppressed local T cell responses to exogenous and nominal parasite antigens. IDO ablation reduced local inflammation and parasite burdens, as did pharmacologic inhibition of IDO in mice with established infections. IDO ablation also enhanced local expression of proinflammatory cytokines and induced some CD4(+) T cells to express interleukin (IL) 17. These findings showed that IDO induced by L. major infection attenuated innate and adaptive immune responses. Thus, IDO acts as a molecular switch regulating host responses, and IDO inhibitor drugs are a potential new approach to enhance host immunity to established leishmania infections.

APC dysfunction is correlated with defective suppression of T cell proliferation in human type 1 diabetes.

It is widely believed that CD4(+)CD25(+) regulatory T cells (Treg) are defective in type 1 diabetes (T1D) and other autoimmune diseases. However, this conclusion is based on the suboptimal in vitro suppression results from very small numbers of subjects. Furthermore, the cells responsible for the suboptimal suppression have not been defined. Therefore, we carried out extensive in vitro suppression assays using both autologous and heterologous donors of Tregs, effector T cells and antigen-presenting cells (APC) from both T1D patients and normal controls. Our in vitro suppression data indicated that a significantly higher proportion (40.0%) of T1D patients have "very low suppression" activity (defined as<25%) by autologous Treg compared to controls (6.3%) (p=0.002). Meta-analysis of the published results confirmed this observation with 45.7% low suppressors in T1D and 7.8% in controls (p=0.00002). Interestingly, suppression assays using heterologous Tregs, effector T cells and APC suggest that the source of APC is correlated with the suppression activity. The frequencies of CD4(+)CD25(+) and CD4(+)CD25(hi) T cells were found to increase with age in normal controls but not in T1D patients, resulting in significantly higher frequencies of CD4(+)CD25(+) (p=0.001) and CD4(+)CD25(hi) (p=0.009) T cells in young T1D subjects than age-matched controls but slightly lower CD4(+)CD25(+) (p=0.003) and CD4(+)CD25(hi) (p=0.08) T cells in old T1D subjects than age-matched controls.

Type 1 diabetes patients have significantly lower frequency of plasmacytoid dendritic cells in the peripheral blood.

Dendritic cells uniquely orchestrate the delicate balance between T cell immunity and regulation and an imbalance favoring immunogenic rather than tolerogenic DC is believed to contribute to the development of autoimmune diseases such as type 1 diabetes (T1D). In this study, we determined the frequencies of three blood DC subsets (pDC, mDC1 and mDC2) in 72 T1D patients and 75 normal controls using the Miltenyi blood DC enumeration kit. The frequency of blood pDC was found to be negatively correlated with subject age in both normal controls and T1D patients (p=0.0007), while the frequency of mDC1 and mDC2 do not change significantly with subject age. More importantly, the mean frequency of pDC in blood was, after adjusting for age, significantly lower in T1D (mean=0.127%) than controls (mean=0.188%) (p<6.0 x 10(-5)), whereas no difference was observed for mDC1 and mDC2 between T1D and controls. Furthermore, T1D patients have a lower proportion of pDC and higher proportion of mDC1 among the total blood DC population than normal controls. These results indicate that the frequency of blood pDC and the pDC/mDC1 ratio are negatively associated with T1D.

Immunology. Antigen-presenting cells in the gut.

It has been known for the past 85 years that mucosal responses can be stimulated by local presentation of antigen and that the gut immune system is capable of mounting both primary and secondary responses to potentially harmful antigens while avoiding the expression of damaging responses to harmless dietary proteins. How these types of responses are induced and regulated remains unclear. In the gut attention has for some time been focused on Peyer's patches (PP) due to evidence that they play a vital role in the induction of humoral and cellular responses. Moreover, it has been established that MHC class II molecules are found in the gut mucosa on a variety of cell types outside PP, namely the lamina propria (LP). Fed antigens have also been detected in the LP and studies have shown that LP cells can stimulate allogeneic mixed lymphocyte responses and are capable of presenting soluble protein antigen to naïve T cells. This article reviews the present understanding of the possible roles of PP and LP in intestinal immunity in terms of induction, regulation, surveillance of immune responses and the antigen presenting cell types involved.

Characterisation of Toxoplasma gondii engineered to express mouse interferon-gamma.

Recent studies have shown the feasibility of using Toxoplasma gondii as an expression system for heterologous protein. For better understanding of the mechanism of interferon-gamma (IFN-gamma) dependent immunity to T. gondii, the parasites were stably transfected with IFN-gamma gene, under control of the GRA1 promoter. Immunofluorescence analyses showed that recombinant mouse IFN-gamma localised to discrete punctuate structures consistent with dense granules and secreted into the vacuolar space. The production of IFN-gamma was detectable in both extracellular parasites and the parasite-infected cells. Growth of the recombinant parasites was inhibited in the mouse macrophage cell line (J774A.1 cells), but not in monkey kidney adherent fibroblasts (Vero cells), demonstrating the species-specificity of IFN-gamma. Addition of anti-mouse IFN-gamma antibody resulted in growth recovery of the recombinant parasites, suggesting that IFN-gamma, secreted from the parasitised host cells across the parasitophorous vacuole membrane, acted in a paracrine manner. Reverse transcription (RT)-PCR analysis revealed significant expression of inducible nitric oxide synthase mRNA and high levels of nitric oxide production in recombinant parasite-infected J774A.1 cells. A competitive inhibitor of the L-arginine-dependent effector pathway, N(G)-monomethyl-L-arginine, inhibited the reduction of recombinant parasite growth in J774A.1 cells. Taken together, our data suggest that the T. gondii expression system may provide a new tool for cytokine gene expression and that parasites engineered to express a cytokine gene may be rationally designed for use in studies on immune responses to T. gondii.

A role for balance of interferon-gamma and interleukin-4 production in protective immunity against Neospora caninum infection.

A suitable balance in the production of Th1/Th2-type cytokines has a crucial role in the control of microbial infections. We investigated cytokine production patterns and effects during Neospora caninum infection, based on two mouse models and an in vitro system. In the acute infection of N. caninum, BALB/c-background IFN-gamma-deficient mice that were sensitive to the N. caninum infection showed high levels of IL-10 production, whereas significant levels of interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) production were observed in resistant wild type mice. BALB/c mice vaccinated with recombinant vaccinia virus expressing N. caninum surface protein NcSRS2 resisted parasite spread throughout the body, low levels of IFN-gamma production and high levels of IL-4 production were observed compared to unvaccinated animals. The treatment of N. caninum-infected cells with IFN-gamma or IL-10 decreased the host-cell viability in an in vitro system using mouse macrophage J774A.1 cells. On the other hand, IL-4, but not IL-10 administration, increased the viability of N. caninum-infected and IFN-gamma-treated cells. In the light of the balance of Th1/Th2-type cytokine production, an IFN-gamma/IL-4 balance may have a crucial role for the control of cellular responses against the parasite invasion.

Viability and infectivity of Cryptosporidium parvum oocysts detected in river water in Hokkaido, Japan.

The viability and infectivity of Cryptosporidium parvum (C. parvum) oocysts, detected in water samples collected from river water in Hokkaido, were investigated using Severe Combined Immunodeficient (SCID) mice. The water samples collected from September 27 through October 10, 2001 by filtration using Cuno cartridge filters were purified and concentrated by the discontinuous centrifugal flotation method. From 1.2 x 10 (5) liters of the raw river water, approximately 2 x 10(4) oocysts were obtained and designated as Hokkaido river water 1 isolate (HRW-1). Oocyst identification was carried out using microscopic and immunological methods. Six 8-week-old female SCID mice were each inoculated orally with 1 x 10 (3) oocysts. Infection was successfully induced, resulting in fecal oocyst shedding. Oocysts were then maintained by sub-inoculation into SCID mice every 3 months. Infectivity was evaluated by making comparisons with two known C. parvum stocks, HNJ-1 and TK-1, which were bovine genotypes detected in fecal samples from a cryptosporidiosis patient and young cattle raised in Tokachi, Hokkaido respectively. The oocyst genotypes were determined from a small subunit ribosomal RNA (SSU-rRNA) gene by polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) analysis. No significant differences were observed in the average number of oocysts per gram of feces (OPG) in any of the isolates. Our data indicates that the C. parvum oocysts detected in the sampled river water were of C. parvum genotype 2. Moreover, our data on the continued isolation, detection and identification of the C. parvum isolates is consistent with the available epidemiological data for the Tokachi area.