S3: Social-network Simulation System with Large Language Model-Empowered Agents

Social network simulation plays a crucial role in addressing various challenges within social science. It offers extensive applications such as state prediction, phenomena explanation, and policy-making support, among others. In this work, we harness the formidable human-like capabilities exhibited by large language models (LLMs) in sensing, reasoning, and behaving, and utilize these qualities to construct the S$^3$ system (short for $\textbf{S}$ocial network $\textbf{S}$imulation $\textbf{S}$ystem). Adhering to the widely employed agent-based simulation paradigm, we employ prompt engineering and prompt tuning techniques to ensure that the agent's behavior closely emulates that of a genuine human within the social network. Specifically, we simulate three pivotal aspects: emotion, attitude, and interaction behaviors. By endowing the agent in the system with the ability to perceive the informational environment and emulate human actions, we observe the emergence of population-level phenomena, including the propagation of information, attitudes, and emotions. We conduct an evaluation encompassing two levels of simulation, employing real-world social network data. Encouragingly, the results demonstrate promising accuracy. This work represents an initial step in the realm of social network simulation empowered by LLM-based agents. We anticipate that our endeavors will serve as a source of inspiration for the development of simulation systems within, but not limited to, social science

Specification of Functional Cranial Placode Derivatives from Human Pluripotent Stem Cells

Cranial placodes are embryonic structures essential for sensory and endocrine organ development. Human placode development has remained largely inaccessible despite the serious medical conditions caused by the dysfunction of placode-derived tissues. Here, we demonstrate the efficient derivation of cranial placodes from human pluripotent stem cells. Timed removal of the BMP inhibitor Noggin, a component of the dual-SMAD inhibition strategy of neural induction, triggers placode induction at the expense of CNS fates. Concomitant inhibition of fibroblast growth factor signaling disrupts placode derivation and induces surface ectoderm. Further fate specification at the preplacode stage enables the selective generation of placode-derived trigeminal ganglia capable of in vivo engraftment, mature lens fibers, and anterior pituitary hormone-producing cells that upon transplantation produce human growth hormone and adrenocorticotropic hormone in vivo. Our results establish a powerful experimental platform to study human cranial placode development and set the stage for the development of human cell-based therapies in sensory and endocrine disease

Preclinical Efficacy and Safety of a Human Embryonic Stem Cell-Derived Midbrain Dopamine Progenitor Product, MSK-DA01

Parkinson's disease is characterized by the loss of dopaminergic neurons in the substantia nigra leading to disabling deficits. Dopamine neuron grafts may provide a significant therapeutic advance over current therapies. We have generated midbrain dopamine neurons from human embryonic stem cells and manufactured large-scale cryopreserved dopamine progenitors for clinical use. After optimizing cell survival and phenotypes in short-term studies, the cell product, MSK-DA01, was subjected to an extensive set of biodistribution, toxicity, and tumorigenicity assessments in mice under GLP conditions. A large-scale efficacy study was also performed in rats with the same lot of cells intended for potential human use and demonstrated survival of the grafted cells and behavioral amelioration in 6-hydroxydopamine lesioned rats. There were no adverse effects attributable to the grafted cells, no obvious distribution outside the brain, and no cell overgrowth or tumor formation, thus paving the way for a future clinical trial