An Fc-Small Molecule Conjugate for Targeted Inhibition of the Adenosine 2A Receptor

The adenosine A_2A receptor (A_2A R) is expressed in immune cells, as well as brain and heart tissue, and has been intensively studied as a therapeutic target for multiple disease indications. Inhibitors of the A_2A R have the potential for stimulating immune response, which could be valuable for cancer immune surveillance and mounting a response against pathogens. One well-established potent and selective small molecule A_2A R antagonist, ZM-241385 (ZM), has a short pharmacokinetic half-life and the potential for systemic toxicity due to A_2A R effects in the brain and the heart. In this study, we designed an analogue of ZM and tethered it to the Fc domain of the immunoglobulin IgG3 by using expressed protein ligation. The resulting protein-small molecule conjugate, Fc-ZM, retained high affinity for two Fc receptors: FcγRI and the neonatal Fc receptor, FcRn. In addition, Fc-ZM was a potent A_2A R antagonist, as measured by a cell-based cAMP assay. Cell-based assays also revealed that Fc-ZM could stimulate interferon γ production in splenocytes in a fashion that was dependent on the presence of A_2A R. We found that Fc-ZM, compared with the small molecule ZM, was a superior A_2A R antagonist in mice, consistent with the possibility that Fc attachment can improve pharmacokinetic and/or pharmacodynamic properties of the small molecule.

A selective phenelzine analogue inhibitor of histone demethylase LSD1

Lysine-specific demethylase 1 (LSD1) is an epigenetic enzyme that oxidatively cleaves methyl groups from monomethyl and dimethyl Lys4 of histone H3 (H3K4Me1, H3K4Me2) and can contribute to gene silencing. This study describes the design and synthesis of analogues of a monoamine oxidase antidepressant, phenelzine, and their LSD1 inhibitory properties. A novel phenelzine analogue (bizine) containing a phenyl-butyrylamide appendage was shown to be a potent LSD1 inhibitor in vitro and was selective versus monoamine oxidases A/B and the LSD1 homologue, LSD2. Bizine was found to be effective at modulating bulk histone methylation in cancer cells, and ChIP-seq experiments revealed a statistically significant overlap in the H3K4 methylation pattern of genes affected by bizine and those altered in LSD1–/– cells. Treatment of two cancer cell lines, LNCaP and H460, with bizine conferred a reduction in proliferation rate, and bizine showed additive to synergistic effects on cell growth when used in combination with two out of five HDAC inhibitors tested. Moreover, neurons exposed to oxidative stress were protected by the presence of bizine, suggesting potential applications in neurodegenerative disease.

An Fc domain protein-small molecule conjugate as an enhanced immunomodulator

Proteins as well as small molecules have demonstrated success as therapeutic agents, but their pharmacologic properties sometimes fall short against particular drug targets. Although the adenosine 2a receptor (A(2A)R) has been identified as a promising target for immunotherapy, small molecule A(2A)R agonists have suffered from short pharmacokinetic half-lives and the potential for toxicity by modulating nonimmune pathways. To overcome these limitations, we have tethered the A(2A)R agonist CGS-21680 to the immunoglobulin Fc domain using expressed protein ligation with Sf9 cell secreted protein. The protein small molecule conjugate Fc-CGS retained potent Fc receptor and A(2A)R interactions and showed superior properties as a therapeutic for the treatment of a mouse model of autoimmune pneumonitis. This approach may provide a general strategy for optimizing small molecule therapeutics.

Architectural organization of the metabolic regulatory enzyme ghrelin O-acyltransferase

Ghrelin O-acyltransferase (GOAT) is a polytopic integral membrane protein required for activation of ghrelin, a secreted metabolism-regulating peptide hormone. Although GOAT is a potential therapeutic target for the treatment of obesity and diabetes and plays a key role in other physiologic processes, little is known about its structure or mechanism. GOAT is a member of the membrane-bound O-acyltransferase (MBOAT) family, a group of polytopic integral membrane proteins involved in lipid-biosynthetic and lipid-signaling reactions from prokaryotes to humans. Here we use phylogeny and a variety of bioinformatic tools to predict the topology of GOAT. Using selective permeabilization indirect immunofluorescence microscopy in combination with glycosylation shift immunoblotting, we demonstrate that GOAT contains 11 transmembrane helices and one reentrant loop. Development of the V5Glyc tag, a novel, small, and sensitive dual topology reporter, facilitated these experiments. The MBOAT family invariant residue His-338 is in the ER lumen, consistent with other family members, but conserved Asn-307 is cytosolic, making it unlikely that both are involved in catalysis. Photocross-linking of synthetic ghrelin analogs and inhibitors demonstrates binding to the C-terminal region of GOAT, consistent with a role of His-338 in the active site. This knowledge of GOAT architecture is important for a deeper understanding of the mechanism of GOAT and other MBOATs and could ultimately advance the discovery of selective inhibitors for these enzymes.

Dietary patterns and diet quality among diverse older adults: the University of Alabama at Birmingham Study of Aging

OBJECTIVES

To characterize dietary patterns among a diverse sample of older adults (≥ 65 years).

DESIGN

Cross-sectional.

SETTING

Five counties in west central Alabama.

PARTICIPANTS

Community-dwelling Medicare beneficiaries (N=416; 76.8 ± 5.2 years, 56% female, 39% African American) in the University of Alabama at Birmingham (UAB) Study of Aging.

MEASUREMENTS

Dietary data collected via three, unannounced 24-hour dietary recalls was used to identify dietary patterns. Foods were aggregated into 13 groups. Finite mixture modeling (FMM) was used to classify individuals into three dietary patterns. Differences across dietary patterns for nutrient intakes, sociodemographic, and anthropometric measurements were examined using chi-square and general linear models.

RESULTS

Three dietary patterns were derived. A "more healthful" dietary pattern, with relatively higher intakes of fruit, vegetables, whole grains, eggs, nuts, legumes and dairy, was associated with lower energy density, higher quality diets as determined by healthy eating index (HEI)-2005 scores and higher intakes of fiber, folate, vitamins C and B6, calcium, iron, magnesium, and zinc. The "western-like" pattern was defined by an intake of starchy vegetables, refined grains, meats, fried poultry and fish, oils and fats and was associated with lower HEI-2005 scores. The "low produce, high sweets" pattern was characterized by high saturated fat, and low dietary fiber and vitamin C intakes. The strongest predictors of better diet quality were female gender and non-Hispanic white race.

CONCLUSION

The dietary patterns identified may provide a useful basis on which to base dietary interventions targeted at older adults. Examination of nutrient intakes regardless of the dietary pattern suggests that older adults are not meeting nutrient recommendations and should continue to be encouraged to choose high quality diets.

Dietary patterns and relationship to obesity-related health outcomes and mortality in adults 75 years of age or greater

BACKGROUND

The prevalence of obesity-related adverse health outcomes is increasing among older adults. Because it is thought that nutrition plays an important role in successful aging, there has been considerable interest in the association between dietary patterns of older adults and obesity-related health outcomes.

OBJECTIVE

This study examined the association between dietary patterns and mortality and prevalence of obesity-related health outcomes, namely cardiovascular disease (CVD), type 2 diabetes mellitus, hypertension, and metabolic syndrome (MetSyn), over a 5-year follow-up period in adults aged 75 years or greater.

DESIGN

A longitudinal observational study with cross-sectional dietary assessment.

SETTING

Rural Central Pennsylvania.

PARTICIPANTS

Community-dwelling older adults (N = 449; 76.5 years old; 57% female).

MEASUREMENTS

Multiple, unannounced, 24-hour dietary recalls were used to collect dietary intake. Cluster analysis was used to derive dietary patterns. Prevalence of CVD, diabetes mellitus, hypertension, and MetSyn was extracted from outpatient electronic medical records. Logistic regression was used to examine the associations between dietary patterns and health outcomes and mortality.

RESULTS

'Sweets and Dairy', 'Health-Conscious' and 'Western' dietary patterns were identified. Compared to the 'Health-Conscious' pattern, those in the 'Sweets and Dairy' pattern had increased odds of hypertension over the follow-up period; adjusted odds ratio (95% CI) was 2.18 (1.11-4.30). No significant associations were found for CVD, diabetes mellitus, MetSyn or mortality with dietary patterns.

CONCLUSIONS

These findings support the potential value of healthy dietary patterns in the management of hypertension in older adults. We did not observe any other strong associations between dietary patterns and health outcomes or mortality in persons ≥ 75 years of age; thus failing to support the use of overly restrictive diet prescriptions for older persons, especially where food intake may be inadequate.

Ghrelin O-acyltransferase assays and inhibition

Ghrelin O-acyltransferase (GOAT) is responsible for catalyzing the attachment of the eight-carbon fatty acid octanoyl to the Ser3 side chain of the peptide ghrelin to generate the active form of this metabolic hormone. As such, GOAT is viewed as a potential therapeutic target for the treatment of obesity and diabetes mellitus. Here, we review recent progress in the development of cell and in vitro assays to measure GOAT action and the identification of several synthetic GOAT inhibitors. In particular, we discuss the design, synthesis, and characterization of the bisubstrate analog GO-CoA-Tat and its ability to modulate weight and blood glucose in mice. We also highlight current challenges and future research directions in our biomedical understanding of this fascinating ghrelin processing enzyme.

Prenatal diagnosis of de novo interstitial deletion of proximal 4q by maternal serum screening for Down syndrome

Deletion of the proximal portion of chromosome 4q is apparently rare. To our knowledge, prenatal diagnosis of the interstitial deletion of 4q12-21.1 has never been reported. We present a prenatal case of 4q deletion in association with a positive Down syndrome screening test of an elevated maternal serum free beta human chorionic gonadotrophin (beta-hCG) level. The prenatal sonogram revealed intra-uterine growth retardation (IUGR) and shortening of the femur. Facial dysmorphism included micrognathia, depressed nasal bridge and low-set ears, these anomalies were evident at the postnatal examination. All of the anomalies were consistent with those described in proximal 4q deletion syndrome. Our case suggests that chromosome studies may be indicated for patients with high maternal serum free beta-hCG and IUGR in the early second trimester.