Cell Biology seminars

Jiaqi Zhang examines how computational models can learn the effects of genetic interventions from single-cell experiments. Such experiments reveal causal relationships, but their high-dimensional measurements are costly to collect and difficult to interpret. The seminar connects identifiable causal representations with a predictive method for previously unseen perturbations. The approach incorporates prior biological knowledge and changes in data distributions to estimate responses at individual-cell resolution. It also uses predictions to guide subsequent experiments. An application identifies and experimentally validates previously unknown T-cell regulators with potential relevance to cancer immunotherapy. The recording follows the original July seminar; the series lists Zhang at MIT, while the recording biography describes her incoming Columbia appointment.

Ant colonies depend heavily on chemical communication, creating demanding problems for sensory gene regulation. This lecture examines the expansion of olfactory-receptor gene families and the mechanisms that select a receptor for each neuron. Comparisons with vertebrates illuminate how stochastic gene choices support organised sensory systems.

This lecture uses the fruit-fly visual system to examine how neuronal diversity emerges from developing stem cells. Differences between the timing of cell division and developmental progression can produce varied cell lineages. The discussion considers how related principles might help explain diversity in the mammalian cortex and retina.

This lecture asks how developing brains generate many distinct neuronal types. It examines the contribution of a stem cell's spatial origin and its changing developmental state. Work in simpler nervous systems provides molecular examples that can inform the study of human cortical development.

Shimon Sakaguchi, Mary E. Brunkow and Fred Ramsdell explain how peripheral immune tolerance prevents the immune system from attacking the body. Sakaguchi follows the identification of regulatory T cells, the CD25 marker, and the relationship between central tolerance and active suppression of self-reactive cells. He considers how changing regulatory T-cell activity could support cancer treatment and transplantation. Brunkow describes genetic investigation of scurfy mice, identification of FOXP3, and the connection between mutations in this gene and human IPEX syndrome. The work establishes a molecular basis for the development and function of regulatory T cells. Ramsdell traces the move from these basic discoveries toward therapeutic strategies, including engineering a patient’s regulatory T cells to target inflammation in rheumatoid arthritis. He discusses early clinical investigation and the ambition of restoring immune balance; these approaches are presented as developing treatments rather than established cures.

Emmanuelle Passegué examines why mechanisms that maintain blood-forming stem cells in early life can contribute to their deterioration with age. The lecture connects cell-cycle control, marrow support, inflammation, metabolic regulation and cellular memory to altered self-renewal and blood-cell production. It also considers genomic instability, clonal hematopoiesis and progression toward leukemia.