Sex-determining genes distinctly regulate courtship capability and target preference via sexually dimorphic neurons.

For successful mating, a male animal must execute effective courtship behaviors toward a receptive target sex, which is female. Whether the courtship execution capability and upregulation of courtship toward females are specified through separable sex-determining genetic pathways remains uncharacterized. Here, we found that one of the two Drosophila sex-determining genes, doublesex (dsx), specifies a male-specific neuronal component that serves as an execution mechanism for courtship behavior, whereas fruitless (fru) is required for enhancement of courtship behavior toward females. The dsx-dependent courtship execution mechanism includes a specific subclass within a neuronal cluster that co-express dsx and fru. This cluster contains at least another subclass that is specified cooperatively by both dsx and fru. Although these neuronal populations can also promote aggressive behavior toward male flies, this capacity requires fru-dependent mechanisms. Our results uncover how sex-determining genes specify execution capability and female-specific enhancement of courtship behavior through separable yet cooperative neurogenetic mechanisms.

Age-dependent overall survival benefit of androgen deprivation therapy for metastatic prostate cancer.

BACKGROUND: Androgen deprivation therapy (ADT) remains a standard of care in metastatic prostate cancer. Recent prospective trials have explored addition of chemotherapy to ADT. We retrospectively examined overall survival in metastatic prostate cancer patients treated with ADT, chemotherapy plus ADT (C + ADT), or observation from 2004 to 2010 using National Cancer Database data. METHODS: Using the National Cancer Database, 21,977 patients with metastatic prostate cancer diagnosed from 2004 to 2010 were identified. Multivariate logistic regression, Kaplan-Meier survival analysis and Cox proportional hazards regression modeling were implemented, with overall survival as the primary endpoint. RESULTS: Five-year overall survival was 13.6% in patients aged ≥ 75 years vs. 30.1% (age 65-74) and 34.5% (age 18-64). Subgroup analysis of age-based cohorts (<65 and ≥65 years) showed poor overall survival for C + ADT vs. ADT alone, both in younger (HR 1.35, 95% CI 1.21-1.50; p < 0.0001) as well as older (HR 1.21, 95% CI 1.08-1.34; p = 0.0006) populations. Younger patients had no significant difference in overall survival for observation vs. ADT (HR 0.99, 95% CI 0.92-1.08; p = 0.9121). Besides age, other factors impacting overall survival included race, rural/urban settings, comorbidity score, income, PSA and radiation. DISCUSSION: Younger patients had no significant difference in overall survival between observation or ADT. This implies a group of younger patients in whom ADT does not confer any overall survival benefit. Future clinical trials with genetic and biologic markers are needed to delineate which subgroups would not benefit from C + ADT or ADT alone. This is of utmost clinical importance given the negative impact of ADT on quality of life and comorbidities.

Differential Muscarinic Modulation in the Olfactory Bulb.

Neuromodulation of olfactory circuits by acetylcholine (ACh) plays an important role in odor discrimination and learning. Early processing of chemosensory signals occurs in two functionally and anatomically distinct regions, the main and accessory olfactory bulbs (MOB and AOB), which receive extensive cholinergic input from the basal forebrain. Here, we explore the regulation of AOB and MOB circuits by ACh, and how cholinergic modulation influences olfactory-mediated behaviors in mice. Surprisingly, despite the presence of a conserved circuit, activation of muscarinic ACh receptors revealed marked differences in cholinergic modulation of output neurons: excitation in the AOB and inhibition in the MOB. Granule cells (GCs), the most abundant intrinsic neuron in the OB, also exhibited a complex muscarinic response. While GCs in the AOB were excited, MOB GCs exhibited a dual muscarinic action in the form of a hyperpolarization and an increase in excitability uncovered by cell depolarization. Furthermore, ACh influenced the input-output relationship of mitral cells in the AOB and MOB differently showing a net effect on gain in mitral cells of the MOB, but not in the AOB. Interestingly, despite the striking differences in neuromodulatory actions on output neurons, chemogenetic inhibition of cholinergic neurons produced similar perturbations in olfactory behaviors mediated by these two regions. Decreasing ACh in the OB disrupted the natural discrimination of molecularly related odors and the natural investigation of odors associated with social behaviors. Thus, the distinct neuromodulation by ACh in these circuits could underlie different solutions to the processing of general odors and semiochemicals, and the diverse olfactory behaviors they trigger. SIGNIFICANCE STATEMENT: State-dependent cholinergic modulation of brain circuits is critical for several high-level cognitive functions, including attention and memory. Here, we provide new evidence that cholinergic modulation differentially regulates two parallel circuits that process chemosensory information, the accessory and main olfactory bulb (AOB and MOB, respectively). These circuits consist of remarkably similar synaptic arrangement and neuronal types, yet cholinergic regulation produced strikingly opposing effects in output and intrinsic neurons. Despite these differences, the chemogenetic reduction of cholinergic activity in freely behaving animals disrupted odor discrimination of simple odors, and the investigation of social odors associated with behaviors signaled by the Vomeronasal system.