Illuminating the druggable genome: Pathways to progress

There are ∼4500 genes within the 'druggable genome', the subset of the human genome that expresses proteins able to bind drug-like molecules, yet existing drugs only target a few hundred. A substantial subset of druggable proteins are largely uncharacterized or understudied, with many falling within G protein-coupled receptor (GPCR), ion channel, and kinase protein families. To improve scientific understanding of these three understudied protein families, the US National Institutes of Health launched the Illuminating the Druggable Genome Program. Now, as the program draws to a close, this review will lay out resources developed by the program that are intended to equip the scientific community with the tools necessary to explore previously understudied biology with the potential to rapidly impact human health.

Characterization of olfactomedin 4+ cells in prostate and urethral-tube epithelium during murine postnatal development and in adult mice

Olfactomedin4 (Olfm4) is expressed in normal mouse prostate. However, Olfm4+ cells in the murine prostate have not been well characterized. In this study, we generated an Olfm4^eGFP reporter mouse line with C57BL/6 mice and investigated the distribution of Olfm4/eGFP-expressing cells during postnatal development from P1, P7, P14, P20, P42, P56 to adult male mouse prostate and urethral tube. We observed Olfm4/eGFP expression in urogenital and prostatic epithelial cells during early postnatal development, which persisted into adulthood in urethral-tube and anterior-prostate (AP) epithelium. We found Olfm4+ cells are E-cadherin+/CD44+/Foxa1+ and some of subpopulation are Ck8+/Ck5+/Sca-1-/Ck4-/Syn- in the adult mouse AP epithelium. Functional studies of single-cell preparations of Olfm4/eGFP-expressing cells isolated from adult Olfm4^eGFP mouse prostate demonstrated that Olfm4+ cells can grow and form colonies, spheres, or organoids in culture. Bioinformatic analysis of Olfm4+ cells using single-cell RNA sequencing meta data in adult mouse urethra (GSE145865) identified upregulation of genes related to cell and tissue migration and development, as well as upregulation of xenobiotic metabolism signaling pathways. In conclusion, Olfm4^eGFP mouse is a novel model to further study Olfm4's biological functions and Olfm4+ cells may contribute importantly to cellular processes supporting development and homeostasis of the epithelium in murine prostate and urethral tube.

Abstract 2453: Olfactomedin 4 downregulation enhances MYC-signaling in human benign prostate cells and the Olfm4 mouse models

Prostate cancer is the most diagnosed solid tumor and the second leading cause of cancer related death in American men. We have reported previously that OLFM4 gene expression was reduced or lost during prostate cancer progression due to frequent genetic deletion and hypermethylation of the OLFM4 gene promoter region. To investigate OLFM4 gene biological functions and molecular mechanisms underlying prostate cancer progression, we have established OLFM4 knock out RWPE1 cells and Olfm4 knock out mouse model. Functionally, OLFM4-knockout RWPE1 cells exhibited enhanced proliferation of the stem/progenitor-like cell population and abnormal differentiation. Bulk-cell RNA sequencing analysis pinpointed that MYC expression was enhanced in the OLFM4-knockout RWPE1 cells compared with OLFM4-wild cells. Molecular and signaling pathway studies revealed an increase in the WNT/APC/MYC signaling pathway gene signature and MYC target genes that regulate multiple biological processes in OLFM4-knockout RWPE1 cells and Olfm4-knock out mouse models. To test the function of the MYC gene in RWPE1 cells, we used (+)-JQ1, an MYC inhibitor, in both 2D and 3D culture models and found that (+)-JQ1 substantially inhibited the proliferation of OLFM4-knockout GFP reporter RWPE1 cells compared with OLFM4-W RWPE1 cells in both types of cultures. We further studied MYC inhibitors using organoid culture for Olfm4-/-/TRAMP mouse prostate tumors. These results suggest that OLFM4-negative prostate cancer is more sensitive to MYC inhibitor’s therapeutic approaches.

Citation Format: Hongzhen Li, Wenli Liu, Jianqiong Zhu, Kay Chin, Griffin P. Rodgers. Olfactomedin 4 downregulation enhances MYC-signaling in human benign prostate cells and the Olfm4 mouse models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2453.

Kruppel-like factor 1-GATA1 fusion protein improves the sickle cell disease phenotype in mice both in vitro and in vivo

Sickle cell disease (SCD) and β-thalassemia are among the most common genetic disorders worldwide, affecting global health and mortality. Hemoglobin A2 (HbA2, α2δ2) is expressed at a low level in adult blood due to the lack of the Kruppel-like factor 1 (KLF1) binding motif in the δ-globin promoter region. However, HbA2 is fully functional as an oxygen transporter, and could be a valid antisickling agent in SCD, as well as a substitute for hemoglobin A in β-thalassemia. We have previously demonstrated that KLF1-GATA1 fusion protein could interact with the δ-globin promoter and increase δ-globin expression in human primary CD34+ cells. We report the effects of 2 KLF1-GATA1 fusion proteins on hemoglobin expression, as well as SCD phenotypic correction in vitro and in vivo. Forced expression of KLF1-GATA1 fusion protein enhanced δ-globin gene and HbA2 expression, as well as reduced hypoxia-related sickling, in erythroid cells cultured from both human sickle CD34+ cells and SCD mouse hematopoietic stem cells (HSCs). The fusion proteins had no impact on erythroid cell differentiation, proliferation, and enucleation. Transplantation of highly purified SCD mouse HSCs expressing KLF1-GATA1 fusion protein into SCD mice lessened the severity of the anemia, reduced the sickling of red blood cells, improved SCD-related pathological alterations in spleen, kidney, and liver, and restored urine-concentrating ability in recipient mice. Taken together, these results indicate that the use of KLF1-GATA1 fusion constructs may represent a new gene therapy approach for hemoglobinopathies.

Olfactomedin 4 Is a Biomarker for the Severity of Infectious Diseases

Biomarkers of infectious diseases are essential tools for patient monitoring, diagnostics, and prognostics. Here we review recent advances in our understanding of olfactomedin 4 (OLFM4) in neutrophil biology and of OLFM4 as a new biomarker for certain infectious diseases. OLFM4 is a neutrophil-specific granule protein that is expressed in a subset of human and mouse neutrophils. OLFM4 expression is upregulated in many viral and bacterial infections, as well as in malaria. OLFM4 appears to play an important role in regulating host innate immunity against bacterial infection. Further, higher expression of OLFM4 is associated with severity of disease for dengue virus, respiratory syncytial virus, and malaria infections. In addition, higher expression of OLFM4 or a higher percentage of OLFM4 + neutrophils is associated with poorer outcomes in septic patients. OLFM4 is a promising biomarker and potential therapeutic target in certain infectious diseases.

COVID-19 and metabolic diseases: a heightened awareness of health inequities and a renewed focus for research priorities

Chronic metabolic disorders such as diabetes and obesity are major public health issues in the United States. However, significant disparities in their prevalence and incidence place a greater burden on US racial and ethnic minority groups, contributing to worse COVID-19 outcomes in many. Improving treatment and prevention of diabetes and obesity is critical to the NIDDK. In this Perspective, we will review the burden of metabolic diseases in the United States, the observed disparities for metabolic diseases in relation to COVID-19, and research opportunities to address underlying causes of metabolic diseases, their associated health disparities, and COVID-19.

Olfactomedin 4 mediation of prostate stem/progenitor-like cell proliferation and differentiation via MYC

Olfactomedin 4 (OLFM4) is expressed in normal prostate epithelial cells and immortalized normal human prostate epithelial cells (RWPE1), but the identity of OLFM4-expressing cells within these populations and OLFM4's physiological functions in these cells have not been elucidated. Using single-cell RNA sequencing analysis, we found here that OLFM4 was expressed in multiple stem/progenitor-like cell populations in both the normal prostate epithelium and RWPE1 cells and was frequently co-expressed with KRT13 and LY6D in RWPE1 cells. Functionally, OLFM4-knockout RWPE1 cells exhibited enhanced proliferation of the stem/progenitor-like cell population, shifts stem/progenitor-like cell division to favor symmetric division and differentiated into higher levels PSA expression cells in organoid assays compared with OLFM4-wild RWPE1 cells. Bulk-cell RNA sequencing analysis pinpointed that cMYC expression were enhanced in the OLFM4-knockout RWPE1 cells compared with OLFM4-wild cells. Molecular and signaling pathway studies revealed an increase in the WNT/APC/MYC signaling pathway gene signature, as well as that of MYC target genes that regulate multiple biological processes, in OLFM4-knockout RWPE1 cells. These findings indicated that OLFM4 is co-expressed with multiple stem/progenitor cell marker genes in prostate epithelial cells and acts as a novel mediator in prostate stem/progenitor cell proliferation and differentiation.

Olfactomedin 4 downregulation is associated with tumor initiation, growth and progression in human prostate cancer

The olfactomedin 4 (OLFM4) gene has been analyzed as a tumor‐suppressor gene and a putative biomarker in many cancers. In our study, we analyzed the relationship of OLFM4 expression with clinicopathological features and with CpG site methylation in the OLFM4 gene promoter region in human primary prostate adenocarcinoma. OLFM4 protein expression was significantly reduced in prostate cancer tissue compared to adjacent normal tissue and was further significantly reduced in more advanced cancers. Bioinformatic studies with clinical datasets revealed that primary prostate adenocarcinoma patients with reduced OLFM4 mRNA expression exhibited higher Gleason scores and higher preoperative serum prostate‐specific antigen levels, as well as lower recurrence‐free survival. Three of the eight CpG sites in the OLFM4 gene promoter region were hypermethylated in cancerous prostate cells compared to adjacent normal cells, and reduced methylation of eight CpG sites was associated with increased OLFM4 mRNA expression in RWPE1 and PC‐3 cells. Furthermore, knockdown of OLFM4 gene expression was associated with enhanced epithelial–mesenchymal transition (EMT)‐marker expression in RWPE immortalized normal prostate cells. In contrast, restoration of OLFM4 expression in PC‐3 and DU145 prostate cancer cells lacking OLFM4 significantly inhibited both EMT‐marker expression and tumor cell growth in in vitro and in vivo models, indicating that OLFM4 may play a tumor‐suppressor role in inhibiting the EMT program, as well as tumor initiation and growth, in prostate cells. Taken together, these findings suggest that OLFM4 plays an important tumor‐suppressor role in prostate cancer progression and might be useful as a novel candidate biomarker for prostate cancer.

What's new?

Altered expression of the OLFM4 gene appears to be involved in many cancers. In this study of prostate cancers, the authors found that OLFM4 can suppress tumor initiation, growth and progression. Downregulation of OLFM4 was associated with higher serum PSA levels, higher Gleason scores, and lower recurrence‐free survival in prostate cancer patients. These results indicate that OLFM4 may play an important tumor‐suppressor role in the progression of prostate cancer, and may provide a novel prognostic biomarker for prostate cancer treatment.

Natural history of benign ethnic neutropenia in individuals of African ancestry

BACKGROUND

Benign ethnic neutropenia (BEN), defined by neutrophil count <1.5 k/μL in the absence of other causes, is an asymptomatic condition more commonly observed in individuals of African ancestry. However, the natural history of this condition has been less well described.

METHODS

Individuals with BEN were retrospectively identified by chart review or referral to hematology clinics. They were then invited to enroll in a prospective natural history study. Retrospective and prospective clinical and laboratory data were combined for descriptive analyses.

FINDINGS

46 participants, younger and older adults from 2 institutions, had BEN. Hypertension was reported in 30%, musculoskeletal disorders in 15%, and upper respiratory infection in 33% of these adults. Their leukopenia resulted from isolated neutropenia, ranging from 1000 and 1500 cells/μL. The severity of infections was mild and the frequency was similar to other healthy individuals in the ambulatory clinic.

INTERPRETATION

In this group of BEN participants, their leukopenia was stable over time, and they had low rates of infections or common medical disorders, confirming the benign nature of this condition. The presence of BEN in children, younger adults, and older adults suggest a hereditary pattern for BEN.

Olfactomedin 4 Deletion Improves Male Mouse Glucose Intolerance and Insulin Resistance Induced by a High-Fat Diet

Glucose-stimulated insulin secretion (GSIS) is essential for blood glucose homeostasis and is impaired in type 2 diabetes mellitus. Understanding the regulatory components of GSIS has clinical implications for diabetes treatment. In this study, we found that olfactomedin 4 (OLFM4) is endogenously expressed in pancreatic islet β cells and further investigated its potential roles in glucose homeostasis and the pathogenesis of type 2 diabetes using mouse models. Olfm4-deficient mice showed significantly improved glucose tolerance and significantly increased insulin levels after glucose challenge compared with wild-type (WT) mice. GSIS, mitochondrial ATP production, and mitochondrial respiration were all significantly increased in islets isolated from Olfm4-deficient mice compared with those isolated from WT mice. In a high-fat diet (HFD)-induced diabetic mouse model, the increase in insulin levels after glucose challenge was significantly higher in Olfm4-deficient mice compared with WT mice. The impaired glucose tolerance and insulin resistance in HFD-fed mice were improved by loss of Olfm4. Olfm4 was found to be mainly localized in the mitochondria and interacts with GRIM-19 (a gene associated with retinoid-interferon mortality) in Min6 pancreatic β cells. Collectively, these studies suggest that Olfm4 negatively regulates GSIS. OLFM4 may represent a potential therapeutic target for impaired glucose tolerance and patients with type 2 diabetes.

Olfactomedin 4 contributes to hydrogen peroxide-induced NADPH oxidase activation and apoptosis in mouse neutrophils

Neutrophils increase production of reactive oxygen species, including superoxide, hydrogen peroxide (H₂O₂), and hydroxyl radical, to destroy invading microorganisms under pathological conditions. Conversely, oxidative stress conditions, such as the presence of H₂O₂, induce neutrophil apoptosis, which helps to remove neutrophils after inflammation. However, the detailed molecular mechanisms that are involved in the latter process have not been elucidated. In this study, we investigated the potential role of olfactomedin 4 (Olfm4) in H₂O₂-induced superoxide production and apoptosis in mouse neutrophils. We have demonstrated that Olfm4 is not required for maximal-dosage PMA- and Escherichia coli bacteria-induced superoxide production, but Olfm4 contributes to suboptimal-dosage PMA- and H₂O₂-induced superoxide production. Using an NADPH oxidase inhibitor and gp91phox-deficient mouse neutrophils, we found that NAPDH oxidase was required for PMA-stimulated superoxide production and that Olfm4 mediated H₂O₂-induced superoxide production through NADPH oxidase, in mouse neutrophils. We have shown that neutrophils from Olfm4-deficient mice exhibited reduced H₂O₂-induced apoptosis compared with neutrophils from wild-type mice. We also demonstrated that neutrophils from Olfm4-deficient mice exhibited reduced H₂O₂-stimulated mitochondrial damage and membrane permeability, and as well as reduced caspase-3 and caspase-9 activity, compared with neutrophils from wild-type mice. Moreover, the cytoplasmic translocation of the proapoptotic mitochondrial proteins Omi/HtrA2 and Smac/DIABLO in response to H₂O₂ was reduced in neutrophils from Olfm4-deficient mice compared with neutrophils from wild-type mice. Our study demonstrates that Olfm4 contributes to H₂O₂-induced NADPH oxidase activation and apoptosis in mouse neutrophils. Olfactomedin 4 might prove to be a potential target for future studies on inflammatory neutrophil biology and for inflammatory disease treatment.

Discovery of phenylsulfonylfuroxan derivatives as gamma globin inducers by histone acetylation

N-oxide derivatives 5(a-b), 8(a-b), and 11(a-c) were designed, synthesized and evaluated in vitro and in vivo as potential drugs that are able to ameliorate sickle cell disease (SCD) symptoms. All of the compounds demonstrated the capacity to releasing nitric oxide at different levels ranging from 0.8 to 30.1%, in vivo analgesic activity and ability to reduce TNF-α levels in the supernatants of monocyte cultures. The most active compound (8b) protected 50.1% against acetic acid-induced abdominal constrictions, while dipyrone, which was used as a control only protected 35%. Compounds 8a and 8b inhibited ADP-induced platelet aggregation by 84% and 76.1%, respectively. Both compounds increased γ-globin in K562 cells at 100 μM. The mechanisms involved in the γ-globin increase are related to the acetylation of histones H3 and H4 that is induced by these compounds. In vitro, the most promising compound (8b) was not cytotoxic, mutagenic and genotoxic.

Analyses of genome wide association data, cytokines, and gene expression in African-Americans with benign ethnic neutropenia

BACKGROUND

Benign ethnic neutropenia (BEN) is a hematologic condition associated with people of African ancestry and specific Middle Eastern ethnic groups. Prior genetic association studies in large population showed that rs2814778 in Duffy Antigen Receptor for Chemokines (DARC) gene, specifically DARC null red cell phenotype, was associated with BEN. However, the mechanism of this red cell phenotype leading to low white cell count remained elusive.

METHODS

We conducted an extreme phenotype design genome-wide association study (GWAS), analyzed ~16 million single nucleotide polymorphisms (SNP) in 1,178 African-Americans individuals from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) study and replicated from 819 African-American participants in the Atherosclerosis Risk in Communities (ARIC) study. Conditional analyses on rs2814778 were performed to identify additional association signals on chromosome 1q22. In a separate cohort of healthy individuals with and without BEN, whole genome gene expression from peripheral blood neutrophils were analyzed for DARC.

RESULTS

We confirmed that rs2814778 in DARC was associated with BEN (p = 4.09×10-53). Conditioning on rs2814778 abolished other significant chromosome 1 associations. Inflammatory cytokines (IL-2, 6, and 10) in participants in the Howard University Family Study (HUFS) and Multi-Ethnic Study in Atherosclerosis (MESA) showed similar levels in individuals homozygous for the rs2814778 allele compared to others, indicating cytokine sink hypothesis played a minor role in leukocyte homeostasis. Gene expression in neutrophils of individuals with and without BEN was also similar except for low DARC expression in BEN, suggesting normal function. BEN neutrophils had slightly activated profiles in leukocyte migration and hematopoietic stem cell mobilization pathways (expression fold change <2).

CONCLUSIONS

These results in humans support the notion of DARC null erythroid progenitors preferentially differentiating to myeloid cells, leading to activated DARC null neutrophils egressing from circulation to the spleen, and causing relative neutropenia. Collectively, these human data sufficiently explained the mechanism DARC null red cell phenotype causing BEN and further provided a biologic basis that BEN is clinically benign.

Abstract 861: Olfactomedin 4 downregulation is associated with enhancing epithelial-mesenchymal transition in human benign prostate cells and prostate cancer cells

We have previously reported that lost or reduced olfactomedin 4 (OLFM4) expression is caused by deletions within the OLFM4 gene in 10-25% of all human prostate-cancer samples, and that its expression is lost in more than 58% of advanced prostate-cancer samples. Therefore, we sought to study the role of epigenetic factors in the regulation of OLFM4 gene expression in normal prostate, as well as prostate-cancer, cell lines. Pyrosequencing of genomic DNA extracted from normal prostate or prostate-cancer tissue cells demonstrated that three of the eight CpG sites in the OLFM4 gene promoter were significantly hypermethylated in prostate cancer compared with normal tissue. Exposure to the methylation inhibitor 5-azadeoxycytidine (5-Aza 5 μM) significantly increased OLFM4 expression in RWPE1 benign prostate cells. Knockdown of OLFM4 expression in RWPE benign prostate cells reduced autophagy and enhanced the epithelial-mesenchymal transition (EMT). Restoration of OLFM4 expression in metastatic prostate-cancer cells lacking OLFM4 inhibited cell growth in both in vitro culture models and an in vivo xenograft tumor model, and also inhibited EMT marker gene expression in these cells. 5-Aza induced OLFM4 expression in PC-3 prostate cancer cells and OLFM4 shRNA transfected PC-3 cells affects 5-Aza mediated cell proliferation compared to control-shRNA transfected PC-3 cells. Taken together, our results suggest that OLFM4 inhibits the EMT program in both normal prostate and prostate-cancer cells, and may play a critical role in regulating the EMT program during the progression of cancer. They also suggest that modulation of OLFM4 expression might be a novel molecular target for advancing prostate-cancer therapies.

Citation Format: Hongzhen Li, Wenli Liu, Jianqiong Zhu, Kay Chin, Jaime Rodriguez-Canales, Griffin P. Rodgers. Olfactomedin 4 downregulation is associated with enhancing epithelial-mesenchymal transition in human benign prostate cells and prostate cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 861. doi:10.1158/1538-7445.AM2017-861

Social Determinants of Racial Disparities in CKD

Significant disparities in CKD rates and outcomes exist between black and white Americans. Health disparities are defined as health differences that adversely affect disadvantaged populations, on the basis of one or more health outcomes. CKD is the complex result of genetic and environmental factors, reflecting the balance of nature and nurture. Social determinants of health have an important role as environmental components, especially for black populations, who are disproportionately disadvantaged. Understanding the social determinants of health and appreciating the underlying differences associated with meaningful clinical outcomes may help nephrologists treat all their patients with CKD in an optimal manner. Altering the social determinants of health, although difficult, may embody important policy and research efforts, with the ultimate goal of improving outcomes for patients with kidney diseases, and minimizing the disparities between groups.

NIH Precision Medicine Initiative: Implications for Diabetes Research

In his January 2015 State of the Union address, President Barack Obama announced a new Precision Medicine Initiative (PMI) to personalize approaches toward improving health and treating disease (www.whitehouse.gov/precision-medicine). He stated that the goal of such an initiative was "to bring us closer to curing diseases like cancer and diabetes, and to give all of us access to the personalized information we need to keep ourselves and our families healthier." Since that time, the National Institutes of Health (NIH) has taken a leadership role in implementing the President's vision related to biomedical research (www.nih.gov/precisionmedicine). Here, we discuss the NIH component of the PMI, related ongoing diabetes research, and near-term research that could position the diabetes field to take full advantage of the opportunities that stem from the PMI.

Advancing a Comprehensive Approach to the Study of Lower Urinary Tract Symptoms

PURPOSE

Lower urinary tract symptoms are common in the United States population, leading to significant economic, quality of life and public health issues. The burden will increase as the population ages, and risk factors for lower urinary tract symptoms, including diabetes and obesity, remain highly prevalent. Improving clinical management and establishing the knowledge base to prevent lower urinary tract symptoms will require a comprehensive research approach that examines factors beyond the lower urinary tract. While the study of extra-lower urinary tract factors has increased recently, current urological research does not systematically account for the broad set of potential contributing factors spanning biological, behavioral, psychological/executive function and sociocultural factors. A comprehensive assessment of potential contributors to risk, treatment response and progression is necessary to reduce the burden of this condition in the United States.

MATERIALS AND METHODS

We considered challenges to continuing the predominantly lower urinary tract dysfunction centric approach that has dominated previous research of lower urinary tract symptoms.

RESULTS

We developed a new, comprehensive framework for urology research that includes a broader set of potential factors contributing to lower urinary tract symptoms. This framework aims to broaden research to consider a comprehensive set of potential contributing factors and to engage a broad range of researchers in the investigation of as many extra-lower urinary tract factors as possible, with the goal of improving clinical care and prevention.

CONCLUSIONS

We propose a new framework for future urology research, which should help to reduce the medical and economic burden of lower urinary tract symptoms in the United States population.

Glia Maturation Factor-γ Regulates Monocyte Migration through Modulation of β1-Integrin

Monocyte migration requires the dynamic redistribution of integrins through a regulated endo-exocytosis cycle, but the complex molecular mechanisms underlying this process have not been fully elucidated. Glia maturation factor-γ (GMFG), a novel regulator of the Arp2/3 complex, has been shown to regulate directional migration of neutrophils and T-lymphocytes. In this study, we explored the important role of GMFG in monocyte chemotaxis, adhesion, and β1-integrin turnover. We found that knockdown of GMFG in monocytes resulted in impaired chemotactic migration toward formyl-Met-Leu-Phe (fMLP) and stromal cell-derived factor 1α (SDF-1α) as well as decreased α5β1-integrin-mediated chemoattractant-stimulated adhesion. These GMFG knockdown impaired effects could be reversed by cotransfection of GFP-tagged full-length GMFG. GMFG knockdown cells reduced the cell surface and total protein levels of α5β1-integrin and increased its degradation. Importantly, we demonstrate that GMFG mediates the ubiquitination of β1-integrin through knockdown or overexpression of GMFG. Moreover, GMFG knockdown retarded the efficient recycling of β1-integrin back to the plasma membrane following normal endocytosis of α5β1-integrin, suggesting that the involvement of GMFG in maintaining α5β1-integrin stability may occur in part by preventing ubiquitin-mediated degradation and promoting β1-integrin recycling. Furthermore, we observed that GMFG interacted with syntaxin 4 (STX4) and syntaxin-binding protein 4 (STXBP4); however, only knockdown of STXBP4, but not STX4, reduced monocyte migration and decreased β1-integrin cell surface expression. Knockdown of STXBP4 also substantially inhibited β1-integrin recycling in human monocytes. These results indicate that the effects of GMFG on monocyte migration and adhesion probably occur through preventing ubiquitin-mediated proteasome degradation of α5β1-integrin and facilitating effective β1-integrin recycling back to the plasma membrane.

Type 1 Diabetes--Reaping the Rewards of a Targeted Research Investment

The Diabetes Control and Complications Trial (DCCT) precipitated a major research effort to develop new approaches to achieve near-normal glycemic control in real-world settings in people with type 1 diabetes. Toward that end, a unique funding stream from the U.S. Congress-the Special Statutory Funding Program for Type 1 Diabetes Research-has provided nearly $2.5 billion for research into the prevention, cure, and treatment of type 1 diabetes since 1998. This funding generated a targeted, sustained investment in type 1 diabetes research with six specific goals: identifying new therapeutic targets through the understanding of disease etiology and pathogenesis, preventing or reversing the disease, developing cell replacement therapy, improving management and care, preventing or reducing the complications, and attracting new talent and applying new technologies to type 1 diabetes research. This Perspective describes exciting results that have emerged from the investment and further advances on the horizon, including artificial pancreas technologies, new therapies for diabetic retinopathy, and breakthroughs in laboratory production of β-cells. The recent program extension enables us to build on this foundation and pursue key new initiatives to harness emerging technologies and develop the next generation of type 1 diabetes researchers.

Olfactomedin 4 deficiency promotes prostate neoplastic progression and is associated with upregulation of the hedgehog-signaling pathway

Loss of olfactomedin 4 (OLFM4) gene expression is associated with the progression of human prostate cancer, but its role and the molecular mechanisms involved in this process have not been completely understood. In this study, we found that Olfm4-knockout mice developed prostatic intraepithelial neoplasia and prostatic adenocarcinoma. Importantly, we found that the hedgehog-signaling pathway was significantly upregulated in the Olfm4-knockout mouse model. We also found that restoration of OLFM4 in human prostate-cancer cells that lack OLFM4 expression significantly downregulated hedgehog signaling-pathway component expression. Furthermore, we demonstrated that the OLFM4 protein interacts with sonic hedgehog protein, as well as significantly inhibits GLI-reporter activity. Bioinformatic and immunohistochemistry analyses revealed that decreased OLFM4 and increased SHH expression was significantly associated with advanced human prostate cancer. Thus, olfactomedin 4 appears to play a critical role in regulating progression of prostate cancer, and has potential as a new biomarker for prostate cancer.

Evolutionary context for the association of γ-globin, serum uric acid, and hypertension in African Americans

Background

Hyperuricemia and associated cardio-metabolic disorders are more prevalent in African Americans than in European Americans. We used genome-wide admixture mapping and association testing to identify loci with ancestry effects on serum uric acid levels.

Methods

We analyzed 1,976 African Americans from Washington, D.C, including 1,322 individuals from 328 pedigrees and 654 unrelated individuals, enrolled in the Howard University Family Study. We performed admixture mapping and genome-wide association testing using ~800 k autosomal single-nucleotide polymorphisms (SNPs). We performed fine mapping by dense genotyping. We assessed functionality by a combination of bioinformatic annotation, reporter gene assays, and gel shift experiments. We also analyzed 12,641 individuals enrolled in the National Health and Nutrition Examination Survey.

Results

We detected a genome-wide significant locus on chromosome 11p15.4 at which serum uric acid levels increased with increasing African ancestry, independent of kidney function. Fine-mapping identified two independent signals in the β-globin locus. The ancestral allele at SNP rs2855126, located upstream of the hemoglobin, gamma A gene HBG1, was associated with increased serum uric acid levels and higher expression of a reporter gene relative to the derived allele. Hyperuricemia was associated with increased risk of hypertension in 3,767 African Americans (Odds Ratio = 2.48, p = 2.71 × 10^− 19).

Conclusions

Given that increased expression of γ-globin leads to increased levels of fetal hemoglobin which confers protection against malaria, we hypothesize that evolution in Africa of protection against malaria may have occurred at the cost of increased serum uric acid levels, contributing to the high rates of hyperuricemia and associated cardio-metabolic disorders observed in African Americans.

Electronic supplementary material

The online version of this article (doi:10.1186/s12881-015-0249-z) contains supplementary material, which is available to authorized users.

Abstract 4344: Olfactomedin 4 plays a tumor-suppressor role and is a novel candidate biomarker in the prostate cancer progression and independent of PSA

Prostate cancer is the most commonly diagnosed solid tumor and the second leading cause of cancer-related death in the American male population. The olfactomedin 4 gene (OLFM4) plays critical tumor suppressor roles in human and murine prostate cancer. We have previously reported that loss or reduce of OLFM4 expression is associated with the progression of human prostate cancer. We further found that loss of Olfm4 leads to prostate neoplastic progression in the Olfm4-knockout mouse model.

To study the clinical impacts of OLFM4 gene in the prostate cancer, we have performed bioinformatics analysis from the published datasets, GSE35988, GSE21032 and TCGA as well as immunohistochemical analysis with prostate cancer tissue arrays by using OLFM4 antibody. The copy number variations (CNV) of OLFM4 gene were significantly associated with Gleason scores of prostate cancer. The pattern of OLFM4 CNV is similar with other tumor suppressor genes, RB1, PTEN and P53. We have observed consist reduce or loss of mRNA expression in the castrate resistant and metastatic prostate cancer patient samples. To study the relationship between OLFM4 expression and prostate cancer recurrence, we performed Kaplan-Meier Plots and Log-rank statistic analysis for GSE21032 and TCGA data sets. Overall, there was no significant relationship between OLFM4 expression and prostate cancer recurrence. However, when analysis was restricted to the lower quartile of OLFM4 expression, we obtained a highly significant inverse relationship (p = 0.02) between OLFM4 expression and recurrence. We also observed that alteration of CNV and expression of OLFM4 gene has no relationship with the level of (patient) serum prostate specific antigen (PSA).

We performed immunohistochemical analysis with prostate cancer tissue arrays by using OLFM4, PSA and E-cadherin antibodies. Lower or loss of expression of OLFM4 protein is associated with advanced Gleason scores of prostate cancer specimens. The pattern of OLFM4 protein expression in prostate cancer patient samples is similar to that of E-cadherin, but not PSA.

Taken together, these results suggest that OLFM4 plays a tumor-suppressor role, and therefore is a likely therapeutic target for prostate cancer interdiction.

Citation Format: Hongzhen Li, Ye Chen, Wenli Liu, Jianqiong Zhu, Chin Kay, Xujing Wang, Griffin P. Rodgers. Olfactomedin 4 plays a tumor-suppressor role and is a novel candidate biomarker in the prostate cancer progression and independent of PSA. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4344. doi:10.1158/1538-7445.AM2015-4344

Urinary Stone Disease: Progress, Status, and Needs

Urinary stone disease (USD) is an important healthcare problem in the US affecting both adults and children, and costs $10 billion to the nation. Prevalence of USD has nearly doubled during the last 15 years in parallel to the obesity and type 2 diabetes epidemic. Despite the advances in the management of an acute episode, one of three stone formers experience recurrence. A better understanding of stone formation is necessary to develop secondary prevention strategies. There are many unanswered research questions that require a multidisciplinary approach. National Institute of Diabetes and Digestive and Kidney Diseases recently held a workshop on USD, and is committed to continue conducting and supporting research in this field.

Abstract 604: Olfactomedin 4 inhibits prostate stem/progenitor cells growth through regulating the hedgehog signaling pathway

The olfactomedin 4 gene (OLFM4) plays critical tumor suppressor roles in human and murine prostate cancer. We have previously reported that loss or reduce of OLFM4 expression is associated with the progression of human prostate cancer. We further found that loss of Olfm4 leads to prostate neoplastic progression in the Olfm4-knockout mouse model. To study the cellular and molecular mechanisms underlying neoplastic progression of the prostate, we have performed gene chip microarray and quantitative real-time RT-PCR analysis to compare Olfm4 knockout with wild-type mouse prostate. The gene-expression signature of prostate tissues from Olfm4-deficient mice revealed significant changes for genes associated with neoplastic progression. In this study, we further detected that hedgehog signaling-pathway components are up-regulated in Olfm4-knockout mice. Since hedgehog signaling pathways are involved in regulating prostate stem/ progenitor cell proliferation, we performed sphere formation analysis with Olfm4 mutant mouse prostate and found that loss of Olfm4 increased proliferative abilities of prostate stem/progenitor cells. Interestingly, administration of human OLFM4 protein and cyclopamine, a specific inhibitor of Shh-signaling pathway, into the sphere culture media reduced Olfm4-deficient mouse prostate stem/progenitor cell growth.

To extend the observation from the mouse model, we established OLFM4-GFP fusion stably expressing cell clones by using human prostate cancer cell lines PC-3, 22RV1 and DU145. We found significant inhibition of sphere and colony formation in OLFM4 expressing cells compared with vector expressing control cells. The expression levels of Shh signaling pathway components were significantly inhibited in OLFM4 expression cells compared to vector expressing control cells.

To detect whether or not OLFM4 down regulates the Shh signaling pathway through interaction with Shh protein, we performed co-immunopricipitation in 293T and PC-3 OLFM4 stably expressing cells. We found that OLFM4 directly interacts with Shh protein. We then carried out Gli- reporter assay using 293T and prostate cancer cells. We demonstrated that expression of OLFM4 inhibited Gli-reporter activity in a dose-dependent manner.

Taken together, these results suggest that OLFM4 inhibits prostate stem/progenitor cells growth by mediating the Shh signaling pathway through a direct interaction of OLFM4 with Shh protein.

Citation Format: Hongzhen Li, Wenli Liu, Weiping Chen, Jianqiong Zhu, Chu-Xia Deng, Griffin P. Rodgers. Olfactomedin 4 inhibits prostate stem/progenitor cells growth through regulating the hedgehog signaling pathway. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 604. doi:10.1158/1538-7445.AM2014-604

Nonmyeloablative HLA-matched sibling allogeneic hematopoietic stem cell transplantation for severe sickle cell phenotype

IMPORTANCE

Myeloablative allogeneic hematopoietic stem cell transplantation (HSCT) is curative for children with severe sickle cell disease, but toxicity may be prohibitive for adults. Nonmyeloablative transplantation has been attempted with degrees of preparative regimen intensity, but graft rejection and graft-vs-host disease remain significant.

OBJECTIVE

To determine the efficacy, safety, and outcome on end-organ function with this low-intensity regimen for sickle cell phenotype with or without thalassemia.

DESIGN, SETTING, AND PARTICIPANTS

From July 16, 2004, to October 25, 2013, 30 patients aged 16-65 years with severe disease enrolled in this nonmyeloablative transplant study, consisting of alemtuzumab (1 mg/kg in divided doses), total-body irradiation (300 cGy), sirolimus, and infusion of unmanipulated filgrastim mobilized peripheral blood stem cells (5.5-31.7 × 10(6) cells/kg) from human leukocyte antigen-matched siblings.

MAIN OUTCOMES AND MEASURES

The primary end point was treatment success at 1 year after the transplant, defined as a full donor-type hemoglobin for patients with sickle cell disease and transfusion independence for patients with thalassemia. The secondary end points were the level of donor leukocyte chimerism; incidence of acute and chronic graft-vs-host disease; and sickle cell-thalassemia disease-free survival, immunologic recovery, and changes in organ function, assessed by annual brain imaging, pulmonary function, echocardiographic image, and laboratory testing.

RESULTS

Twenty-nine patients survived a median 3.4 years (range, 1-8.6), with no nonrelapse mortality. One patient died from intracranial bleeding after relapse. As of October 25, 2013, 26 patients (87%) had long-term stable donor engraftment without acute or chronic graft-vs-host disease. The mean donor T-cell level was 48% (95% CI, 34%-62%); the myeloid chimerism levels, 86% (95% CI, 70%-100%). Fifteen engrafted patients discontinued immunosuppression medication with continued stable donor chimerism and no graft-vs-host disease. The normalized hemoglobin and resolution of hemolysis among engrafted patients were accompanied by stabilization in brain imaging, a reduction of echocardiographic estimates of pulmonary pressure, and allowed for phlebotomy to reduce hepatic iron. The mean annual hospitalization rate was 3.23 (95% CI, 1.83-4.63) the year before, 0.63 (95% CI, 0.26-1.01) the first year after, 0.19 (95% CI, 0-0.45) the second year after, and 0.11 (95% CI, 0.04-0.19) the third year after transplant. For patients taking long-term narcotics, the mean use per week was 639 mg (95% CI, 220-1058) of intravenous morphine-equivalent dose the week of their transplants and 140 mg (95% CI, 56-225) 6 months after transplant. There were 38 serious adverse events: pain and related management, infections, abdominal events, and sirolimus related toxic effects.

CONCLUSIONS AND RELEVANCE

Among 30 patients with sickle cell phenotype with or without thalassemia who underwent nonmyeloablative allogeneic HSCT, the rate of stable mixed-donor chimerism was high and allowed for complete replacement with circulating donor red blood cells among engrafted participants. Further accrual and follow-up are required to assess longer-term clinical outcomes, adverse events, and transplant tolerance.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00061568.

Olfm4 deletion enhances defense against Staphylococcus aureus in chronic granulomatous disease

Chronic granulomatous disease (CGD) patients have recurrent life-threatening bacterial and fungal infections. Olfactomedin 4 (OLFM4) is a neutrophil granule protein that negatively regulates host defense against bacterial infection. The goal of this study was to evaluate the impact of Olfm4 deletion on host defense against Staphylococcus aureus and Aspergillus fumigatus in a murine X-linked gp91phox-deficiency CGD model. We found that intracellular killing and in vivo clearance of S. aureus, as well as resistance to S. aureus sepsis, were significantly increased in gp91phox and Olfm4 double-deficient mice compared with CGD mice. The activities of cathepsin C and its downstream proteases (neutrophil elastase and cathepsin G) and serum levels of IL-1β, IL-6, IL-12p40, CXCL2, G-CSF, and GM-CSF in Olfm4-deficient as well as gp91phox and Olfm4 double-deficient mice were significantly higher than those in WT and CGD mice after challenge with S. aureus. We did not observe enhanced defense against A. fumigatus in Olfm4-deficient mice using a lung infection model. These results show that Olfm4 deletion can successfully enhance immune defense against S. aureus, but not A. fumigatus, in CGD mice. These data suggest that OLFM4 may be an important target in CGD patients for the augmentation of host defense against bacterial infection.

Glia maturation factor-γ negatively modulates TLR4 signaling by facilitating TLR4 endocytic trafficking in macrophages

TLR4 signaling must be tightly regulated to provide both effective immune protection and avoid inflammation-induced pathology. Thus, the mechanisms that negatively regulate the TLR4-triggered inflammatory response are of particular importance. Glia maturation factor-γ (GMFG), a novel actin depolymerization factor/cofilin superfamily protein that is expressed in inflammatory cells, has been implicated in mediating neutrophil and T cell migration, but its function in macrophage immune response remains unclear. In the current study, the role of GMFG in the LPS-induced TLR4-signaling pathway was investigated in THP-1 macrophages and human primary macrophages. LPS stimulation of macrophages decreased GMFG mRNA and protein expression. We show that GMFG negatively regulates LPS-induced activation of NF-κB-, MAPK-, and IRF3-signaling pathways and subsequent production of proinflammatory cytokines and type I IFN in human macrophages. We found that endogenous GMFG localized within early and late endosomes. GMFG knockdown delayed LPS-induced TLR4 internalization and caused prolonged TLR4 retention at the early endosome, suggesting that TLR4 transport from early to late endosomes is interrupted, which may contribute to enhanced LPS-induced TLR4 signaling. Taken together, our findings suggest that GMFG functions as a negative regulator of TLR4 signaling by facilitating TLR4 endocytic trafficking in macrophages.

Abstract 1990: Loss of Olfactomedin 4 gene leads to neoplastic progression in the murine prostate

The murine olfactomedin 4 gene (Olfm4) encodes an olfactomedin-related glycoprotein whose physiological and pathological functions in the prostate are largely unknown. We have observed that homozygous Olfm4 mutant mice develop prostatic intra epithelial neoplisa (PIN), high grade PIN, adenocarcinoma and metastatic tumor in an age-dependent manner. We also found that increased proliferation of prostate epithelial cells in Olfm4-null mice. In this report, we studied the mechanisms underlying neoplastic progression of Olfm4-deficient mice prostate. We have performed microarray analysis to compare Olfm4 knockout and wild-type mice prostate at 3 and 15 months of ages. A total of 187 genes were found commonly changed in both 3 and 15 months, whereas 894 and 1090 genes were significantly changed in 3 and 15 months respectively. Enrichment Gene Go Diseases analysis showed prostatic neoplasms was at the top of 10 listed diseases. We found that 95 genes for neoplastic procession markers were significantly changed in the prostate of Olfm4-deficient mice. Among the genes, 39 genes were up-regulated and 37 genes were down regulated more than 1.5-fold. The qRT-PCR confirmed consistently higher expression of Ets1, Vav3, Shh, Sdc2, and Mmp19, and down-regulation of the genes Rnasel and Psca in Olfm4 knockout mice compared with Olfm4 wild-type mice. We also confirmed expression of Ets1 and Mmp19 by using western blot and immunohistochemistry analysis.

Interestingly, in the GEO prostate cancer database, which compares tumor to normal tissue and metastatic tumor to normal tissue, expression of OLFM4 and RNASEL were down-regulated, in contrast, expression of ETS1 and MMP19 were up-regulated. Therefore, the gene expression profiles in the GEO database confirmed and extended Ets1, Mmp19 and Rnasel in Olfm4 knockout mice. Our finding indicates that loss of OLFM4 leads to progression of prostate cancer.

Citation Format: Hongzhen Li, Wenli Liu, Jianqiong Zhu, Weiping Chen, Chu-Xia Deng, Griffin P. Rodgers. Loss of Olfactomedin 4 gene leads to neoplastic progression in the murine prostate. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1990. doi:10.1158/1538-7445.AM2013-1990

Diabetes research: a perspective from the National Institute of Diabetes and Digestive and Kidney Diseases

This is the third in a series of articles, invited by the editors of Diabetes, that describes the research programs and aims of organizations committed to funding and fostering diabetes-related research. The first piece, contributed by the Juvenile Diabetes Research Foundation, appeared in the January 2012 issue of Diabetes. The second piece that describes the American Diabetes Association’s research program appeared in the June 2012 issues of Diabetes and Diabetes Care.