Biology subjects

Leinninger, G.

Publications and source records attributed to Leinninger, G..

3 recordsLinked to original sources

bioRxiv2026

Nmur1 and Cckar fail to support functional genetic access in adult dopamine neurons and challenge GPCR atlas assignments

Apuschkin et al. (2024) proposed a GPCR-based transcriptomic atlas for midbrain dopamine (DA) neuron subpopulations, including candidates such as Nmur1, Cckar, and Ffar4. To guide genetic targeting, these markers must reflect functional expression in adult DA neurons. Using in situ hybridization, Cre-dependent reporter lines, and both intracranial and systemic viral approaches, we find no evidence of adult Nmur1-mediated recombination in DA neurons, while Cckar-driven recombination is consistent with developmental expression only. Notably, Ffar4 expression overlaps extensively with Ntsr1 midbrain populations, indicating that it does not define a distinct DA neuron class. Furthermore, analysis of independent spatial transcriptomic datasets together with our MERFISH data shows that many proposed GPCR markers are not detectably expressed in adult DA neurons. These findings demonstrate that transcriptomic enrichment does not always yield reliable adult markers and highlight the need for functional validation prior to use in circuit targeting.

neuroscience↗

bioRxiv2026

A Knock-in Ntsr1-Flp Driver Enables Intersectional and Systemic Targeting of Heterogeneous Midbrain Dopamine Circuits

Precise genetic access to molecularly defined neuronal subpopulations is essential for dissecting circuit heterogeneity. We developed and validated a knock-in neurotensin receptor 1 (Ntsr1)Flpmouse line for intersectional targeting of Ntsr1-expressing neurons. Following delivery of Flp-dependent adeno-associated viral (AAV) reporters, robust recombination was observed throughout the the midbrain and several other brain regions. A subset of Ntsr1+ neurons in the substantia nigra and ventral tegmental area lacked dopaminergic markers, indicating that midbrain Ntsr1 populations comprise both dopaminergic and non-dopaminergic neurons. Systemic delivery of a Cre and Flp-dependent reporter in complementary dual-recombinase configurations revealed configuration-dependent differences in dopaminergic targeting. Cis-gene controls (DatCre;DatFlp) defined the maximal dopaminergic targeting ceiling and helped distinguish true non-dopaminergic targeting from recombinase-dependent off-target labeling. Finally, a dual-recombinase-dependent taCaspase-3 construct enabled selective ablation of midbrain dopamine neurons in vivo, establishing Ntsr1Flp as a versatile driver for scalable Boolean targeting.

neuroscience↗

bioRxiv2022

Mice lacking dopamine production in neurotensin receptor 1 neurons voluntarily undergo time-restricted feeding of high fat diet and resist obesity

The introduction of processed foods high in fat and sugars has caused a dramatic increase in obesity in humans. Diet-induced obesity (DIO) can be modeled in laboratory mice by increasing the fat content of their diet. Previously, it was determined that mice lacking dopamine receptor 1 (Drd1) are completely resistant to DIO and do not eat as much food during the day as control mice. Surprisingly, when Drd1 is restored to the suprachiasmatic nucleus (SCN), which is the central regulator of circadian rhythms, these mice increase day-eating and become obese. The source of dopamine in the SCN is the ventral tegmental area (VTA), but the genetic identity of the dopamine neurons is unknown. Here we create conditional deletion mutants for tyrosine hydroxylase (TH) using neurotensin receptor 1 (Ntsr1) Cre and other Cre drivers and measure feeding and body weight homeostasis on standard and high fat diets. Control mice were susceptible to DIO and overate during the day whereas Ntsr1-Cre conditional knockouts for TH mice did not increase day-eating, nor did they gain much weight on HFD. We used an adeno-associated virus to selectively restore TH to the VTA Ntsr1 neurons and observed an increase in body weight and increased day-eating of HFD. These results implicate VTA Ntsr1 dopamine neurons as promoting out-of-phase feeding behavior on a high fat diet that could be an important contributor to diet-induced obesity.

neuroscience↗