Imoto, K. | Search bioRxiv

bioRxiv2024

Two types of regeneration mechanism in acute liver injury

The liver has a strong regenerative capacity, but the mechanisms of liver regeneration are not well understood. Furthermore, many previous studies on liver regeneration have been conducted in partial hepatectomy models, which may differ from acute liver injury with inflammation and necrosis, as observed in many clinical cases. In this study, we conducted a single-cell RNA-seq analysis (scRNA-seq) of liver regeneration in mice treated with acetaminophen (APAP) using publicly available data. We discovered that two cell proliferation populations appeared simultaneously during a single regenerative process. The two populations differed significantly in terms of differentiation, localization, proliferation rate, and signal response. Furthermore, one of the populations was induced by contact with necrotic tissue and exhibited a higher proliferative capacity with a dedifferentiated feature. These findings can shed new light on liver regeneration and aid in the development of therapeutic strategies for liver failure.

pathology↗

bioRxiv2023

Neural-circuit basis of song preference learning in fruit flies

As observed in human language learning and song learning in birds, the fruit fly Drosophila melanogaster changes its auditory behaviors according to prior sound experiences. Female flies that have heard male courtship songs of the same species are less responsive to courtship songs of different species. This phenomenon, known as song preference learning in flies, requires GABAergic input to pC1 neurons in the central brain, with these neurons playing a key role in mating behavior by integrating multimodal sensory and internal information. The neural circuit basis of this GABAergic input, however, has not yet been identified. Here, we find that pCd-2 neurons, totaling four cells per hemibrain and expressing the sex-determination gene doublesex, provide the GABAergic input to pC1 neurons for song preference learning. First, RNAi-mediated knockdown of GABA production in pCd-2 neurons abolished song preference learning. Second, pCd-2 neurons directly, and in many cases mutually, connect with pC1 neurons, suggesting the existence of reciprocal circuits between pC1 and pCd-2 neurons. Finally, GABAergic and dopaminergic inputs to pCd-2 neurons are necessary for song preference learning. Together, this study suggests that reciprocal circuits between pC1 and pCd-2 neurons serve as a sensory and internal state-integrated hub, allowing flexible control over female copulation. Consequently, this provides a neural circuit model that underlies experience-dependent auditory plasticity. SignificanceTo find a suitable mate, an organism must adapt its behavior based on past experiences. In the case of Drosophila, female assessments of male song signals, which contain information about the status and species of the sender, are experience dependent. Here, we show that reciprocal circuits in the central brain modulate the females song response depending on her previous auditory experiences. These circuits exhibit feedback and lateral inhibition motifs, and are regulated by dopaminergic and GABAergic inputs. While the effects of prior auditory experiences on sound responsiveness have been extensively studied in other species, our research advances the use of Drosophila as a model for dissecting the circuitry underlying experience-dependent auditory plasticity at single-cell resolution.

neuroscience↗