Marta Porniece

8️⃣ Huge thanks to my amazing students Jessie & Charlotte 🙌 and to @StephenXZhang & @andermann_mark (from @harvardmed & @nyuniversity ) for their guidance in analysis, conceptualization, and making sense of it all.

1️⃣ 🥳 Thrilled to share that my postdoc work has finally hit the press! nature.com/articles/s4159… When we started, we didn’t really know what PVH-MC4R neurons do in obesity. Are they still signaling or “dead” (e.g., does the chronically high leptin alter α-MSH–MC4R signaling)? 🧵👇

7️⃣ These findings highlight functional alterations in hypothalamic satiety-promoting neurons and reveal the neural consequences of an obesogenic environment.

6️⃣ 💡 Interestingly, switching from NCD → HFD didn’t further impair PVH-MC4R neurons, suggesting resilience once these circuits are established.

5️⃣ Importantly, switching obese mice back to a “healthy” diet partially restored feeding behavior, but not neural activity,  showing lasting effects of high-fat diet on brain circuits controlling appetite.

4️⃣ 🥬 In lean mice, feeding-evoked responses gradually grow as a meal progresses → signals satiety & meal termination. 🍔 In hig- fat-diet-fed mice, responses start too strong and stay flat — suggesting impaired satiety signal integration.

3️⃣ 🧩 We found that PVH-MC4R neurons integrate satiety signals during feeding, but this process becomes disrupted in diet induced obesity and can’t be fully rescued by dietary intervention.

2️⃣ These questions drove us to study how these neurons integrate satiety signals (brain “calorie counting”) and drive motivation to eat. 🍽️

2⃣A multitrait GWAS of adult obesity Combining genomic on BMI, waist and hip circumference, and waist-to-hip ratio from 2 million individuals, this multitrait GWAS identified 86 novel loci associated w/ obesity. 👉These loci could point to new potential targets for anti-obesity therapies 🔗medrxiv.org/content/10.110…

I read this Cell paper that argues to have discovered a molecule (betaine) that mimics the geroprotective effects of exercise. This is a very valuable multi-omics resource, but the authors seemed to get caught in the rabbit hole of chasing a high-impact narrative🧵

🙏 Huge thanks to our fantastic co-authors, especially Charlotte & Jessica, for their incredible help. Grateful to @StephenXZhang, @andermann_mark for their key contributions to experimental design, writing; to @LehtinenLab for postdoc guidance & Andermann Lab for their insights.

🧬 Our data suggest that in obesity, feeding responses in PVH-MC4R neurons fail to "reset" between meals, possibly due to persistently high leptin and disrupted AgRP/α-MSH signaling. 🎯Future work should assess peptide transmission onto these neurons to pinpoint mechanisms.

🚨Paper alert! 📣  We found abnormal feeding-related neural responses in satiety-promoting, MC4R-expressing neurons in the mouse paraventricular hypothalamus (PVHM-C4R) following diet-induced obesity. biorxiv.org/content/10.110… ​#obesity #feedingbehaviour #obesityresearch

I’m so excited to share our preprint on how brainstem neurons sense and integrate multiple body signals during food consumption. We imaged 1000s of neurons across the lateral parabrachial nucleus (LPBN) in behaving mice. biorxiv.org/content/10.110…

A drop of milkshake takes a wild ride after it is swallowed. Rachel and Kiersten came up with cool strategies for visualizing food passing through the mouse GI tract and mapping the activity of the same 100s of brainstem neurons across weeks during feeding and other behaviors.

Our #brain has a sweet tooth 🧠🍫 Nerve cells that tell to us we are full also make us crave #sweets ! mpg.de/24159607/0211-… @MPI_Metabolism

Our new paper is out in @CellReports We show an inhibitory response of Orexin receptor type 2 (Ox2R) in a subset of MCH neurons. doi.org/10.1016/j.celr…