The Neuroendocrine brain

25.04.2026, Saturday, 12:00-13:30

General focus of the symposium:

In this symposia, the overall theme will be about the neuroendocrine brain with a large focus on the hypothalamus and neurohypophysis, two inter-connected and major evolutionarily conserved brain regions with multiple functions in reproduction and water balance. The speakers are chosen in such a way - that each talk will touch an important aspect of neuroendocrine brain and using four different model organisms. The axonal oxytocin signaling in rat and human brain by Prof. Valery Grinevich (Central Institute of Mental Health, Heidelberg University, Germany), the spatial transcriptomics of mice neurohypophysis by Dr Ewelina Kałużna (Institute of Bioorganic Chemistry, PAS, Poznan), the cell signaling mechanisms underlying vascular permeability in the zebrafish neurohypophysis by Athul R Ramesh (Institute of Molecular Biology & Biotechnology, Adam Mickiewicz University, Poznan). The symposia will unite researchers using different model organism, questions, techniques and functions. Valery and Ewelina are PhD holders, while Athul is a PhD student.

12:00 Valery Grinevich, Prof.

Department of Neuropeptide Research in Psychiatry, Central Institute of Mental Health, Heidelberg University, Germany & International Joint Laboratory for Translational Research on Neuromodulation, Shenzhen Institutes ofAdvanced Technology, Chinese Academy of Sciences, Shenzhen, China

"Axonal Oxytocin Signaling in Rat and Human Brain"

Over the past decade, major advances have deepened our understanding of the oxytocin (OT) system, yet a central question remains: how can a single neuropeptide mediate such diverse actions in the brain? I propose that this diversity arises from distinct types of OT neurons, their widespread axonal projections, and the variety of OT-responsive cell populations across brain regions. In this talk, I will focus on axonal OT projections to the medial prefrontal cortex (mPFC) in rats, demonstrating OT action on local interneurons and its profound facilitation of social interactions. I will also present complementary findings from human stem cell-derived OT neurons, which extend axons toward cortical assembloids and, when integrated into the rat hypothalamus, form functional connections with multiple brain regions and the pituitary. Together, these results reveal conserved principles of axonal OT signaling across species, shedding light on the mechanisms underlying the peptide’s diverse functions in the mammalian brain.

12:40 Ewelina Kałużna, Ph.D

Department of Non-coding RNAs, Institute of Bioorganic Chemistry, Polish Academy of Sciences, Poznań, Poland

"Mapping the mouse pituitary gland in space: a transcriptomic view of the posterior lobe"

The pituitary gland is a central neuroendocrine interface, integrating hypothalamic inputs to regulate systemic physiology. Using spatial transcriptomics on adult mice pituitary sections, we mapped gene expression across all pituitary gland lobes. Visium (10x Genomics) platform enabled characterization of the less densely packed posterior lobe (PL). Dimensionality reduction of the transcriptomic output revealed nine spatial clusters. Further, marker gene expression analysis and cell-type deconvolution showed that cluster number 6 comprised pituicytes in about ~50% of cells, in addition to pericytes, endothelial cells, macrophages. Importantly, we detected magnocellular neuron-specific axonal transcripts in high abundance, namely Avp and Oxt-encoded mRNAs. This observation supports the hypothesis that arginine vasopressin and oxytocin are not only transported, stored and released as peptides from the pituitary, but also actively synthetized there, perhaps on demand. Overall, this dataset provides the first spatially resolved transcriptomic framework of the mouse posterior pituitary and a resource for future studies of pituitary organization and cell-cell signaling within it.

12:53 Athul R Ramesh

Institute of Molecular Biology and Biotechnology, Faculty of Biology, Adam Mickiewicz University in Poznań

"Role of glial pituicytes in regulating neurohypophyseal vascular permeability"

The blood-brain barrier (BBB) serves as a critical safeguard for the central nervous system (CNS), but it also presents a formidable obstacle to effective therapeutic drug delivery. Neurohypophysis (NH), a circumventricular organ, circumvents the BBB due to its specialized fenestrated vasculature, which allows selective molecular permeability. The molecular mechanisms that regulate vascular permeability in the NH are relatively unknown. Our research investigates the genetic and molecular pathways underlying NH vascular permeability, with the aim of identifying key regulators that could be leveraged to modulate BBB permeability. Through transcriptomic datamining, we have identified Sfrp5, a WNT regulator as a potential candidate genes and signaling pathways that may govern NH-specific vascular fenestrations and permeability. Towards this goal, we have been employing pharmacological and genetic perturbations on larval zebrafish to explore the roles of Sfrp5 and WNT signaling in the regulation of neurohypophyseal vascular permeability. Our studies are expected to reveal a novel role of Sfrp5 in the vascular development of a key neuroendocrine interface conserved in vertebrates.