Abstract 036: The Single-cell Gene Expression Landscape Of The Hypothalamus During The Development Of Hypertension In Three Major Models

The hypothalamus plays a key role in blood pressure regulation through coordinating and integrating signals in the central nervous system. However, it’s remains underexplored how the cell signaling network in the hypothalamus changes during the progression of hypertension, the key regulators involved, and whether shared or distinct pathophysiological mechanisms underlie the development of hypertension triggered by various genetic susceptibility or environmental factors. To address these questions, we applied the single-nucleus RNA sequencing technology to analyze hypothalamus samples from three well-established models of hypertension with distinct pathogenesis - mice treated with Ang II, the Dahl salt-sensitive rat, and the spontaneous hypertensive rat - along with their respective controls. Data were obtained from 238,445 nuclei from 24 samples under 12 experimental conditions. By characterizing the cellular composition under different disease conditions, we discovered an elevated glia-to-neuron ratio in Ang II-induced hypertension, with increases of 3.1-fold in astrocytes, 4.0-fold in microglia, and 3.4-fold in oligodendrocytes. Moreover, astrocytes underwent a transition from the resting state to a reactive mode associated with neuroinflammation and stronger neuron adhesion. Additionally, multiple neuronal signal communication pathways were overactivated in response to Ang II, including neurexin-neuroligin signaling, nitric oxide-guanylate cyclase pathway, and glutamate and its receptors. In the salt-sensitive hypertension, a 2.3-fold expansion of pro-inflammatory microglia via Cd74 activation was observed after a short-term high-sodium diet, which leveled off thereafter. With a prolonged high-salt intake, there was a 1.7-fold increase in the proportion of Plagl1+ GABA-ergic neurons. In 26 weeks old spontaneously hypertensive rats, a distinctive 1.4-fold increase in the proportion of Slit3+ Glu-ergic neurons was observed, setting them apart from WKY rats. These findings provide new insights into how the hypothalamus may be involved in the development of hypertension under different disease conditions.