Engineering CREB-activated promoters for adenosine-induced gene expression

Accumulation of the ribonucleoside, adenosine (ADO), triggers a cAMP response element binding protein (CREB)-mediated signaling pathway to suppress the function of immune cells in tumors. Here, we describe a collection of CREB-activated promoters that allow for strong and tunable ADO-induced gene expression in human cells. By optimizing number of CREB transcription factor binding sites and altering the core promoter region of CREB-based hybrid promoters, we created synthetic constructs that drive gene expression to higher levels than strong, endogenous mammalian promoters in the presence of ADO. These synthetic promoters are induced up to 47-fold by ADO, with minimal expression in their "off" state. We further determine that our CREB-based promoters are activated by other compounds that act as signaling analogs, and that combinatorial addition of ADO and these compounds has a synergistic impact on gene expression. Surprisingly, we also detail how background ADO degradation caused by the common cell culture media additive, fetal bovine serum (FBS), confounds experiments designed to determine ADO dose-responsiveness. We show that only after long-term heat deactivation of FBS can our synthetic promoters enable gene expression induction at physiologically relevant levels of ADO. Finally, we demonstrate that the strength of a CREB-based promoter is enhanced by incorporating other transcription factor binding sites.

Corrigendum to "Rational engineering of an improved adenosine deaminase 2 enzyme for weaponizing T-cell therapies": [Immuno-Oncology and Technology 10 (2023) 100394]

[This corrects the article DOI: 10.1016/j.iotech.2023.100394.].

Adolescent neurostimulation of dopamine circuit reverses genetic deficits in frontal cortex function

Dopamine system dysfunction is implicated in adolescent-onset neuropsychiatric disorders. Although psychosis symptoms can be alleviated by antipsychotics, cognitive symptoms remain unresponsive and novel paradigms investigating the circuit substrates underlying cognitive deficits are critically needed. The frontal cortex and its dopaminergic input from the midbrain are implicated in cognitive functions and undergo maturational changes during adolescence. Here, we used mice carrying mutations in Arc or Disc1 to model mesofrontal dopamine circuit deficiencies and test circuit-based neurostimulation strategies to restore cognitive functions. We found that in a memory-guided spatial navigation task, frontal cortical neurons were activated coordinately at the decision-making point in wild-type but not Arc-/- mice. Chemogenetic stimulation of midbrain dopamine neurons or optogenetic stimulation of frontal cortical dopamine axons in a limited adolescent period consistently reversed genetic defects in mesofrontal innervation, task-coordinated neuronal activity, and memory-guided decision-making at adulthood. Furthermore, adolescent stimulation of dopamine neurons also reversed the same cognitive deficits in Disc1+/- mice. Our findings reveal common mesofrontal circuit alterations underlying the cognitive deficits caused by two different genes and demonstrate the feasibility of adolescent neurostimulation to reverse these circuit and behavioral deficits. These results may suggest developmental windows and circuit targets for treating cognitive deficits in neurodevelopmental disorders.

Rational engineering of an improved adenosine deaminase 2 enzyme for weaponizing T-cell therapies

Adenosine is a potent immunosuppressive metabolite that accumulates in the extracellular space within solid tumors and inhibits the antitumor function of native immune cell responses as well as chimeric antigen receptor (CAR) T-cell therapies. Here, we show that engineered human cells can degrade extracellular adenosine through secretion of adenosine deaminase (ADA) enzymes-a possible therapeutic enhancement for CAR T cells. We first determine that the high-activity ADA1 isoform is naturally intracellularly restricted and show that the addition of canonical or computationally predicted secretory peptides did not allow for improved secretion. We did, however, determine that the lower-activity ADA2 isoform is naturally secreted. Thus, we utilized phylogenetic-based structural comparisons to guide a mutational survey of ADA2 active site residues, which when coupled with a high-throughput screen for enhanced ADA2-mediated extracellular adenosine rate allowed isolation of the most catalytically efficient ADA2 variant reported to date. When expressed by human cells, this variant exhibits 30× higher extracellular adenosine degradation activity than the wild-type enzyme. Finally, we demonstrate that Jurkat and CAR T cells engineered to express this secreted, high-activity ADA2 variant can degrade significant amounts of extracellular adenosine in vitro.

Adolescent neurostimulation of dopamine circuit reverses genetic deficits in frontal cortex function

Dopamine system dysfunction is commonly implicated in adolescent-onset neuropsychiatric disorders. Although psychosis symptoms can be alleviated by antipsychotics, cognitive symptoms remain unresponsive to such pharmacological treatments and novel research paradigms investigating the circuit substrates underlying cognitive deficits are critically needed. The frontal cortex and its dopaminergic input from the midbrain are implicated in cognitive functions and undergo maturational changes during adolescence. Here, we used mice carrying mutations in the Arc or DISC1 genes to model mesofrontal dopamine circuit deficiencies and test circuit-based neurostimulation strategies to restore cognitive functions. We found that in a memory-guided spatial navigation task, frontal cortical neurons were activated coordinately at the decision-making point in wild-type but not Arc mutant mice. Chemogenetic stimulation of midbrain dopamine neurons or optogenetic stimulation of frontal cortical dopamine axons in a limited adolescent period consistently reversed genetic defects in mesofrontal innervation, task-coordinated neuronal activity, and memory-guided decision-making at adulthood. Furthermore, adolescent stimulation of dopamine neurons also reversed the same cognitive deficits in DISC1 mutant mice. Our findings reveal common mesofrontal circuit alterations underlying the cognitive deficits caused by two different genes and demonstrate the feasibility of adolescent neurostimulation to reverse these circuit and behavioral deficits. These results may suggest developmental windows and circuit targets for treating cognitive deficits in neurodevelopmental disorders.

Real-world bone turnover marker use: impact on treatment decisions and fracture

The use of bone turnover marker (BTM) testing for patients with osteoporosis in the USA has not been well characterized. This retrospective US-based real-world data study found BTM testing has some association with treatment decision-making and lower fracture risk in patients with presumed osteoporosis, supporting its use in clinical practice.

INTRODUCTION

The purpose of this study was to characterize bone turnover marker (BTM) testing patterns and estimate their clinical utility in treatment decision-making and fragility fracture risk in patients with osteoporosis using a retrospective claims database.

METHODS

Data from patients aged ≥ 50 years with newly diagnosed osteoporosis enrolled in the Truven MarketScan^® Commercial Claims and Encounters and Medicare Supplemental and Co-ordination of Benefits databases from January 2008 to June 2018 were included. Osteoporosis was ascertained by explicit claims, fragility fracture events associated with osteoporosis, or prescribed anti-resorptive or anabolic therapy. BTM-tested patients were 1:1 propensity score matched to those untested following diagnosis. Generalized estimating equation models were performed to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for testing versus no testing on both treatment decision-making and fragility fracture.

RESULTS

Of the 457,829 patients with osteoporosis, 6075 were identified with ≥ 1 BTM test following diagnosis; of these patients, 1345 had a unique treatment decision made ≤ 30 days from BTM testing. The percentage of patients receiving BTM tests increased significantly each year (average annual % change: + 8.1%; 95% CI: 5.6-9.0; p = 0.01). Patients tested were significantly more likely to have a treatment decision (OR: 1.14; 95% CI: 1.13-1.15), and testing was associated with lower odds of fracture versus those untested (OR: 0.87; 95% CI: 0.85-0.88).

CONCLUSION

In this large, heterogeneous population of patients with presumed osteoporosis, BTM testing was associated with treatment decision-making, likely leading to fragility fracture reduction following use.