Advantages of Ciona intestinalis as a Model Organism and Its Applications

With the continuous development of experimental biology, the limitations of commonly utilized model organisms are becoming increasingly apparent. Discrepancies between research conducted on laboratory animals and humans significantly impede the translational application of findings derived from animal experiments. This review introduces ascidian Ciona intestinalis as a novel model organism, an invertebrate that is evolutionarily closest to vertebrates and is a sister group to vertebrates. The review summarizes recent research progress on Ciona intestinalis in various fields to illustrate the significant advantages and promising application prospects of it as a model organism. The research progress outlined in the review mainly encompasses: (1) The whole-genome sequencing of Ciona intestinalis has been determined and numerous related databases have been established. Various embryonic gene editing technologies have been successfully applied, making it an animal model easy to manipulate genetically and study the functions and interactions of target genes visually. (2) In the field of neurobiology, Ciona intestinalis boasts a central nervous system structure similar to that of vertebrates and possesses numerous homologous neuropeptides and hormone molecules. These features grant it an edge in exploring the mechanisms and functional evolution of endocrine and neuroendocrine-related molecules. Additionally, the sensitivity and habituation of its larvae to light stimulation provide an avenue for exploring mechanisms related to behavioral plasticity. (3) In the field of immunology, Ciona intestinalis possesses a mature innate immune system and has evolved precursor genes to the adaptive immune system, with a relatively simple coding of immune-related genes. These features make it an exemplary model organism for immunological studies. (4) In the field of developmental biology, many studies have focused on the notochord development process in Ciona intestinalis and the regulatory mechanisms of gene expression within it, indicating common evolutionary developmental strategies among chordates. Additionally, insights into its heart development also significantly enhance our comprehension on the genetic network of human heart development. (5) In medical research, the ability of Ciona intestinalis to regenerate its neural complex and siphon, as well as the resilience of its heart to recover contractile function from substantial damage, renders it a valuable animal model for the study of regeneration and heart injury. It also has unique advantages as a research model for Alzheimer's disease and new drug development. Furthermore, its brief five-month lifespan facilitates the observation and recording of the entire aging process and the exploration of the effects of various factors on aging. In summary, this review aims to demonstrate that Ciona intestinalis stands out as a model organism with unique attributes and is expected to play a significant role in a wider range of scientific research areas.