Summing up the parts of the hypothalamus

Oxytocin attenuates hypothalamic injury-induced cognitive dysfunction by inhibiting hippocampal ERK signaling and Aβ deposition

In clinical settings, tumor compression, trauma, surgical injury, and other types of injury can cause hypothalamic damage, resulting in various types of hypothalamic dysfunction. Impaired release of oxytocin can lead to cognitive impairment and affect prognosis and long-term quality of life after hypothalamic injury. Hypothalamic injury-induced cognitive dysfunction was detected in male animals. Behavioral parameters were measured to assess the characteristics of cognitive dysfunction induced by hypothalamic-pituitary stalk lesions. Brains were collected for high-throughput RNA sequencing and immunostaining to identify pathophysiological changes in hippocampal regions highly associated with cognitive function after injury to corresponding hypothalamic areas. Through transcriptomic analysis, we confirmed the loss of oxytocin neurons after hypothalamic injury and the reversal of hypothalamic-induced cognitive dysfunction after oxytocin supplementation. Furthermore, overactivation of the ERK signaling pathway and β-amyloid deposition in the hippocampal region after hypothalamic injury were observed, and cognitive function was restored after inhibition of ERK signaling pathway overactivation. Our findings suggest that cognitive dysfunction after hypothalamic injury may be caused by ERK hyperphosphorylation in the hippocampal region resulting from a decrease in the number of oxytocin neurons, which in turn causes β-amyloid deposition.

Transcriptomic Analysis Reveals that Activating Transcription Factor 3/c-Jun/Lgals3 Axis Is Associated with Central Diabetes Insipidus after Hypothalamic Injury

BACKGROUND

Hypothalamic injury causes several complicated neuroendocrine-associated disorders, such as water-electrolyte imbalance, obesity, and hypopituitarism. Among these, central diabetes insipidus (CDI), characterized by polyuria, polydipsia, low urine specific gravity, and deficiency of arginine vasopressin contents, is a typical complication after hypothalamic injury.

METHODS

CDI was induced by hypothalamic pituitary stalk injury in male animals. Behavioral parameters and blood sample were collected to evaluate the characteristics of body fluid metabolism imbalance. The brains were harvested for high-throughput RNA sequencing and immunostaining to identify pathophysiological changes in corresponding hypothalamic nuclei.

RESULTS

Based on transcriptomic analysis, we demonstrated the upregulation of the activating transcription factor 3 (Atf3)/c-Jun axis and identified Lgals3, a microglial activation-related gene, as the most significant target gene in response to the body fluid imbalance in CDI. Furthermore, we found that the microglia possessed elevated phagocytic ability, which could promote the elimination of arginine vasopressin neurons after hypothalamic injury.

CONCLUSION

Our findings suggested that the Atf3/c-Jun/Lgals3 axis was associated with the microglial activation, and might participate in the loss of functional arginine vasopressin neurons in CDI after hypothalamic injury.

The Human Lung Cell Atlas: A High-Resolution Reference Map of the Human Lung in Health and Disease

Lung disease accounts for every sixth death globally. Profiling the molecular state of all lung cell types in health and disease is currently revolutionizing the identification of disease mechanisms and will aid the design of novel diagnostic and personalized therapeutic regimens. Recent progress in high-throughput techniques for single-cell genomic and transcriptomic analyses has opened up new possibilities to study individual cells within a tissue, classify these into cell types, and characterize variations in their molecular profiles as a function of genetics, environment, cell-cell interactions, developmental processes, aging, or disease. Integration of these cell state definitions with spatial information allows the in-depth molecular description of cellular neighborhoods and tissue microenvironments, including the tissue resident structural and immune cells, the tissue matrix, and the microbiome. The Human Cell Atlas consortium aims to characterize all cells in the healthy human body and has prioritized lung tissue as one of the flagship projects. Here, we present the rationale, the approach, and the expected impact of a Human Lung Cell Atlas.