IDO1 Signaling through GCN2 in a Subpopulation of Gr-1 Cells Shifts the IFNγ/IL6 Balance to Promote Neovascularization.

In addition to immunosuppression, it is generally accepted that myeloid-derived suppressor cells (MDSC) also support tumor angiogenesis. The tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase (IDO1) has been implicated in promoting neovascularization through its positioning as a key regulatory node between the inflammatory cytokines IFNγ and IL6. Here, we report that within the heterogeneous expanse of Gr-1 MDSCs, both IDO1 expression and the ability to elicit neovascularization were associated with a minor subset of autofluorescent, CD11b cells.

Reliable detection of indoleamine 2,3 dioxygenase-1 in murine cells and tissues.

The essential amino acid tryptophan is catabolized by the first and rate-limiting enzyme of the kynurenine pathway, indoleamine 2,3-dioxygenase-1 (IDO1). IDO1 is implicated in several diseases including cancer, chronic infection, autoimmune disorders and neurodegenerative diseases. Antibodies that accurately recognize human IDO1 protein in situ in tissues are available, including clone 10.

Preclinical study of the long-range safety and anti-inflammatory effects of high-dose oral meglumine.

Meglumine is a methylamino derivative of sorbitol that is an approved drug excipient. Recent preclinical studies suggest that administration of high-dose oral meglumine can exert beneficial medicinal effects to treat diabetes, obesity, and fatty liver disease (NAFLD/nonalcoholic steatohepatitis [NASH]). Here we address gaps in knowledge about the pharmacology and toxicology of this substance administered at high concentrations to explore its medicinal potential.

Reduction of the expression of the late-onset Alzheimer's disease (AD) risk-factor does not affect amyloid pathology in an AD mouse model.

Alzheimer's disease (AD) is pathologically characterized by the deposition of the β-amyloid (Aβ) peptide in senile plaques in the brain, leading to neuronal dysfunction and eventual decline in cognitive function. Genome-wide association studies have identified the () gene within the second most significant susceptibility locus for late-onset AD. BIN1 is a member of the amphiphysin family of proteins and has reported roles in the generation of membrane curvature and endocytosis.

RhoB antibody alters retinal vascularization in models of murine retinopathy.

Neovascularization in cancer or retinopathy is driven by pathological changes that foster abnormal sprouting of endothelial cells. Mouse genetic studies indicate that the stress-induced small GTPase RhoB is dispensable for normal physiology but required for pathogenic angiogenesis. In diabetic retinopathy, retinopathy of prematurity (ROP) or age-related wet macular degeneration (AMD), progressive pathologic anatomic changes and ischemia foster neovascularization are characterized by abnormal sprouting of endothelial cells.

Inflammatory Reprogramming with IDO1 Inhibitors: Turning Immunologically Unresponsive 'Cold' Tumors 'Hot'.

We discuss how small-molecule inhibitors of the tryptophan (Trp) catabolic enzyme indoleamine 2,3-dioxygenase (IDO) represent a vanguard of new immunometabolic adjuvants to safely enhance the efficacy of cancer immunotherapy, radiotherapy, or 'immunogenic' chemotherapy by leveraging responses to tumor neoantigens. IDO inhibitors re-program inflammatory processes to help clear tumors by blunting tumor neovascularization and restoring immunosurveillance. Studies of regulatory and effector pathways illuminate IDO as an inflammatory modifier.

Stromal cyclin D1 promotes heterotypic immune signaling and breast cancer growth.

The gene encodes the regulatory subunit of a holoenzyme that drives cell autonomous cell cycle progression and proliferation. Herein we show cyclin D1 abundance is increased >30-fold in the stromal fibroblasts of patients with invasive breast cancer, associated with poor outcome. Cyclin D1 transformed hTERT human fibroblast to a cancer-associated fibroblast phenotype.

RhoB blockade selectively inhibits autoantibody production in autoimmune models of rheumatoid arthritis and lupus.

During the development of autoimmune disease, a switch occurs in the antibody repertoire of B cells so that the production of pathogenic rather than non-pathogenic autoantibodies is enabled. However, there is limited knowledge concerning how this pivotal step occurs. Here, we present genetic and pharmacological evidence of a positive modifier function for the vesicular small GTPase RhoB in specifically mediating the generation of pathogenic autoantibodies and disease progression in the K/BxN preclinical mouse model of inflammatory arthritis.

Therapeutic antibody targeting of indoleamine-2,3-dioxygenase (IDO2) inhibits autoimmune arthritis.

Rheumatoid arthritis (RA) is a debilitating inflammatory autoimmune disease with no known cure. Recently, we identified the immunomodulatory enzyme indoleamine-2,3-dioxygenase 2 (IDO2) as an essential mediator of autoreactive B and T cell responses driving RA. However, therapeutically targeting IDO2 has been challenging given the lack of small molecules that specifically inhibit IDO2 without also affecting the closely related IDO1.

A High-Throughput Assay for Rho Guanine Nucleotide Exchange Factors Based on the Transcreener GDP Assay.

Ras homologous (Rho) family GTPases act as molecular switches controlling cell growth, movement, and gene expression by cycling between inactive guanosine diphosphate (GDP)- and active guanosine triphosphate (GTP)-bound conformations. Guanine nucleotide exchange factors (GEFs) positively regulate Rho GTPases by accelerating GDP dissociation to allow formation of the active, GTP-bound complex. Rho proteins are directly involved in cancer pathways, especially cell migration and invasion, and inhibiting GEFs holds potential as a therapeutic strategy to diminish Rho-dependent oncogenesis.

Cardiac-specific disruption of Bin1 in mice enables a model of stress- and age-associated dilated cardiomyopathy.

Non-compensated dilated cardiomyopathy (DCM) leading to death from heart failure is rising rapidly in developed countries due to aging demographics, and there is a need for informative preclinical models to guide the development of effective therapeutic strategies to prevent or delay disease onset. In this study, we describe a novel model of heart failure based on cardiac-specific deletion of the prototypical mammalian BAR adapter-encoding gene Bin1, a modifier of age-associated disease. Bin1 deletion during embryonic development causes hypertrophic cardiomyopathy and neonatal lethality, but there is little information on how Bin1 affects cardiac function in adult animals.

Indoleamine 2,3-dioxygenase pathways of pathogenic inflammation and immune escape in cancer.

Genetic and pharmacological studies of indoleamine 2,3-dioxygenase (IDO) have established this tryptophan catabolic enzyme as a central driver of malignant development and progression. IDO acts in tumor, stromal and immune cells to support pathogenic inflammatory processes that engender immune tolerance to tumor antigens. The multifaceted effects of IDO activation in cancer include the suppression of T and NK cells, the generation and activation of T regulatory cells and myeloid-derived suppressor cells, and the promotion of tumor angiogenesis.

Meglumine exerts protective effects against features of metabolic syndrome and type II diabetes.

Metabolic syndrome, diabetes and diabetes complications pose a growing medical challenge worldwide, accentuating the need of safe and effective strategies for their clinical management. Here we present preclinical evidence that the sorbitol derivative meglumine (N-methyl-D-glucamine) can safely protect against several features of metabolic syndrome and diabetes, as well as elicit enhancement in muscle stamina. Meglumine is a compound routinely used as an approved excipient to improve drug absorption that has not been ascribed any direct biological effects in vivo.

The SOCS3-independent expression of IDO2 supports the homeostatic generation of T regulatory cells by human dendritic cells.

Dendritic cells (DCs) are professional APCs that have a role in the initiation of adaptive immune responses and tolerance. Among the tolerogenic mechanisms, the expression of the enzyme IDO1 represents an effective tool to generate T regulatory cells. In humans, different DC subsets express IDO1, but less is known about the IDO1-related enzyme IDO2.

Specific in situ detection of murine indoleamine 2, 3-dioxygenase.

Indoleamine 2,3-dioxygenase-1 (IDO1) catabolizes the essential amino acid tryptophan, acting as a modifier of inflammation and immune tolerance. Recent work has implicated IDO1 in many human diseases, including in cancer, chronic infection, autoimmune disorders, and neurodegenerative disease, stimulating a major surge in preclinical and clinical studies of its pathogenic functions. In the mouse, IDO1 is expressed widely but in situ detection of the enzyme in murine tissues has been unreliable due to the lack of specific antibodies that do not also react with tissues from animals that are genetically deficient in IDO1.

IDO is a nodal pathogenic driver of lung cancer and metastasis development.

Unlabelled: Indoleamine 2,3-dioxygenase (IDO) enzyme inhibitors have entered clinical trials for cancer treatment based on preclinical studies, indicating that they can defeat immune escape and broadly enhance other therapeutic modalities. However, clear genetic evidence of the impact of IDO on tumorigenesis in physiologic models of primary or metastatic disease is lacking. Investigating the impact of Ido1 gene disruption in mouse models of oncogenic KRAS-induced lung carcinoma and breast carcinoma-derived pulmonary metastasis, we have found that IDO deficiency resulted in reduced lung tumor burden and improved survival in both models.

Cardiac and gastrointestinal liabilities caused by deficiency in the immune modulatory enzyme indoleamine 2,3-dioxygenase.

Indoleamine 2,3-dioxygenase (IDO) modifies adaptive immunity, in part by determining the character of inflammatory responses in the tissue microenvironment. Small molecule inhibitors of IDO are being developed to treat cancer, chronic infections and other diseases, so the systemic effects of IDO disruption on inflammatory phenomena may influence the design and conduct of early phase clinical investigations of this new class of therapeutic agents. Here, we report cardiac and gastrointestinal phenotypes observed in IDO deficient mice that warrant consideration in planned assessments of the safety risks involved in clinical development of IDO inhibitors.

RhoB links PDGF signaling to cell migration by coordinating activation and localization of Cdc42 and Rac.

The small GTPase RhoB regulates endocytic trafficking of receptor tyrosine kinases (RTKs) and the non-receptor kinases Src and Akt. While receptor-mediated endocytosis is critical for signaling processes driving cell migration, mechanisms that coordinate endocytosis with the propagation of migratory signals remain relatively poorly understood. In this study, we show that RhoB is essential for activation and trafficking of the key migratory effectors Cdc42 and Rac in mediating the ability of platelet-derived growth factor (PDGF) to stimulate cell movement.

Celecoxib combined with atorvastatin prevents progression of atherosclerosis.

Background: Increased expression of cyclooxygenase (COX-2) contributes to atherosclerosis. Recent studies suggest that COX-2 inhibitors prevent early plaque development but their effects on established lesions are less clear, while the statins promote plaque stability. The purpose of this study is to investigate whether administering a combination of a COX-2 inhibitor with a statin drug alters plaque progression in apo E-/- mice.

Discovery of a human peptide sequence signaling islet neogenesis.

Objective: To identify triggers for islet neogenesis in humans that may lead to new treatments that address the underlying mechanism of disease for patients with type 1 or type 2 diabetes.

Methods: In an effort to identify bioactive human peptide sequences that might trigger islet neogenesis, we evaluated amino acid sequences within a variety of mammalian pancreas-specific REG genes. We evaluated GenBank, the Basic Local Alignment Search Tool algorithm, and all available proteomic databases and developed large-scale protein-to-protein interaction maps.

RhoB regulates PDGFR-beta trafficking and signaling in vascular smooth muscle cells.

Objective: RhoB is a small GTPase localized at the plasma membrane and endosomes that participates in the regulation of endocytic trafficking of the epidermal growth factor (EGF) receptor and the nonreceptor kinases Src and Akt. This study was performed to determine whether RhoB plays a critical role in trafficking and signaling by the platelet-derived growth factor receptor-beta (PDGFR-beta) in vascular smooth muscle cells.

Methods And Results: Cells derived from RhoB knockout mice failed to proliferate in response to PDGF, and downstream signaling was compromised as reflected by reduced phosphorylation of the effector kinases Akt and ERK1/2.

The select cyclooxygenase-2 inhibitor celecoxib reduced the extent of atherosclerosis in apo E-/- mice.

Many investigators have suggested that immune activation may trigger the atherosclerotic process. The benefits of aspirin in preventing myocardial infarction have been attributed, in part, to its anti-inflammatory effects. Several reports have documented that cyclooxygenase (COX)-2 is up-regulated in human and mouse atherosclerotic lesions.

Novel tryptophan catabolic enzyme IDO2 is the preferred biochemical target of the antitumor indoleamine 2,3-dioxygenase inhibitory compound D-1-methyl-tryptophan.

Small-molecule inhibitors of indoleamine 2,3-dioxygenase (IDO) are currently being translated to clinic for evaluation as cancer therapeutics. One issue related to trials of the clinical lead inhibitor, D-1-methyl-tryptophan (D-1MT), concerns the extent of its biochemical specificity for IDO. Here, we report the discovery of a novel IDO-related tryptophan catabolic enzyme termed IDO2 that is preferentially inhibited by D-1MT.

B23 is a downstream target of polyamine-modulated CK2.

Our previous studies have shown that the overexpression of ornithine decarboxylase (ODC), the rate-limiting enzyme in polyamine biosynthesis, increases the enzymatic activity of the polyamine-responsive enzyme casein kinase 2 (CK2). Because CK2 is known to preferentially associate with the nuclear matrix in response to other trophic stimuli, we investigated the effects of ODC overexpression on CK2 localisation and on the CK2-mediated phosphorylation of a known CK2 substrate, the nucleolar phosphoprotein B23. Immunofluorescence analysis of CK2 and B23 in primary keratinocytes revealed that ODC overexpression resulted in the colocalisation of CK2 with B23 at the nucleolar borders.

Compartmentalization of hnRNP-K during cell cycle progression and its interaction with calponin in the cytoplasm.

Coronary artery blockage, due to cardiovascular disease, is routinely treated by either balloon-angioplasty or bypass surgery. The limited success of these clinical interventions is due at least in part to smooth muscle cell (SMC) proliferation. Here we show that heterogeneous nuclear ribonucleoprotein complex K (hnRNP-K) protein levels increase in SMC with response to serum stimulation in vitro, in the aortas from an animal model of atherosclerosis, and in occluded human vein segments.