Pharmacological modulation of T cell immunity results in long-term remission of autoimmune arthritis.

Chronic inflammatory diseases like rheumatoid arthritis are characterized by a deficit in fully functional regulatory T cells. DNA-methylation inhibitors have previously been shown to promote regulatory T cell responses and, in the present study, we evaluated their potential to ameliorate chronic and acute animal models of rheumatoid arthritis. Of the drugs tested, decitabine was the most effective, producing a sustained therapeutic effect that was dependent on indoleamine 2,3-dioxygenase (IDO) and was associated with expansion of induced regulatory T cells, particularly at the site of disease activity. Treatment with decitabine also caused apoptosis of Th1 and Th17 cells in active arthritis in a highly selective manner. The molecular basis for this selectivity was shown to be ENT1, a nucleoside transporter, which facilitates intracellular entry of the drug and is up-regulated on effector T cells during active arthritis. It was further shown that short-term treatment with decitabine resulted in the generation of a population of regulatory T cells that were able to suppress arthritis upon adoptive transfer. In summary, a therapeutic approach using an approved drug is described that treats active inflammatory disease effectively and generates robust regulatory T cells with the IDO-dependent capacity to maintain remission.

Synthetic single domain antibodies for the conformational trapping of membrane proteins.

Mechanistic and structural studies of membrane proteins require their stabilization in specific conformations. Single domain antibodies are potent reagents for this purpose, but their generation relies on immunizations, which impedes selections in the presence of ligands typically needed to populate defined conformational states. To overcome this key limitation, we developed an in vitro selection platform based on synthetic single domain antibodies named sybodies. To target the limited hydrophilic surfaces of membrane proteins, we designed three sybody libraries that exhibit different shapes and moderate hydrophobicity of the randomized surface. A robust binder selection cascade combining ribosome and phage display enabled the generation of conformation-selective, high affinity sybodies against an ABC transporter and two previously intractable human SLC transporters, GlyT1 and ENT1. The platform does not require access to animal facilities and builds exclusively on commercially available reagents, thus enabling every lab to rapidly generate binders against challenging membrane proteins.

The Augustine blood group system, 48 years in the making.

The high-prevalence antigen, Ata, was first identified in 1967, but it was not until 2015 that Ata became AUG1 of a new blood group system, Augustine (AUG). The new system was established after the identification of the gene encoding Ata and the recognition of a null phenotype (AUG:­1,­2) in an At(a­) patient with an antibody (anti-AUG2) reactive with At(a­) red blood cells. The At(a­) phenotype is very rare and, with the exception of the one family with the null phenotype, has only been found in individuals of African origin. Anti-Ata has been implicated in immediate and delayed hemolytic transfusion reactions, but not in severe hemolytic disease of the fetus and newborn. The Augustine gene is SLC29A1, which encodes the equilibrative nucleoside transporter ENT1. At(a­) (AUG:­1,2) results from homozygosity for c.1171G>A, encoding Glu391Lys, whereas the AUGnull (AUG:­1,­2) phenotype results from homozygosity for a splice site mutation, c.589+1G>C, in the only family where it has been found. Absence of ENT1 in that family may be associated with pseudogout and abnormal bone calcification.

Immunocytochemical detection of hENT1 and hCNT1 in normal tissues, lung cancer cell lines, and NSCLC patient samples.

Nucleoside transporters are essential for the cellular entry, efficacy, and cytotoxicity of several clinically important deoxynucleoside analogs (e.g., cytarabine and gemcitabine). We used immunohistochemistry to determine protein expression levels of the nucleoside transporters hENT1 and hCNT1 in NSCLC cell lines, NSCLC patient samples, and a variety of normal tissues. All 4 NSCLC cell lines expressed high to very high levels of both hENT1 and hCNT1. In NSCLC and normal tissues expression of hENT1 and hCNT1 ranged from completely negative to high. Immunohistochemistry might be a useful tool to predict response to deoxynucleoside analogs in malignancies treated with these drugs.

Expression of the nucleoside-derived drug transporters hCNT1, hENT1 and hENT2 in gynecologic tumors.

Deoxynucleoside analogs are used in the treatment of a variety of solid tumors. Their transport across the plasma membrane may determine their cytotoxicity and thus nucleoside transporter (NT) expression patterns may be of clinical relevance. Lack of appropriate antibodies for use in paraffin-embedded biopsies has been a bottleneck to undertake high-throughput analysis of NT expression in solid tumors. Here we report the characterization of 2 new antibodies raised against the low-affinity equilibrative NTs, hENT1 and hENT2, suitable for that purpose. These 2 antisera, along with a previously characterized antibody that specifically recognizes the high-affinity Na-dependent concentrative NT, hCNT1, have been used to analyze, using a tissue array approach, NT expression in gynecologic cancers (90 ovarian, 80 endometrial and 118 uterine cervix carcinomas). Human CNT1 was not detected in 33% and 39% of the ovarian and uterine cervix carcinomas, respectively, whereas hENT1 and hENT2 expression was significantly retained in a high percentage of tumors (91% and 96% for hENT1, 84% and 98% for hENT2, in ovarian and cervix carcinomas, respectively). Only a few endometrial carcinomas (15%) were found to be negative for hCNT1, but they all retained hENT1 and hENT2 expression. In ovarian cancer, the loss of all 3 NT proteins was a more common event in the clear cell histologic subtype than in the serous, mucinous and endometrioid histotypes. In uterine cervix tumors, the loss of expression of hCNT1 was significantly associated with the adenocarcinoma subtype. In summary, hCNT1 was by far the isoform whose expression was most frequently reduced or lost in the 3 types of gynecologic tumors analyzed. Moreover, NT expression is related to the type of gynecologic tumor and its specific subtype, hCNT1 protein loss being highly correlated with poor prognosis histotypes. Since hCNT1, hENT1 and hENT2 recognize fluoropyrimidines as substrates, but with different affinities, this study anticipates high variability in drug uptake efficiency in solid tumors.