Sergiu P. Pașca (born January 30, 1982) is a Romanian-American scientist and physician at Stanford University in California. He is known for creating and developing stem cell-based models of the human brain and applying organoids and assembloids to gain insights into neuropsychiatric disease.

Pașca is the Kenneth T. Norris Endowed Professor of Psychiatry and Behavioral Sciences at Stanford University^[1] and the Bonnie Uytengsu and Family Founding Director of Stanford Brain Organogenesis,^[2] a neuroscientist and stem cell biologist. He is part of the Stanford Neurosciences Institute, Stanford Bio-X and a fellow of the ChEM-H Institute at Stanford.^[1] Pașca was listed among New York Times Visionaries in Medicine and Sciences, he is the recipient of the 2018 Vilcek Award for Creative Biomedical Promise from the Vlicek Foundation,^[3] and the 2022 IBRO-Kemali Neuroscience Prize,^[4] and he holds a Doctor Honoris Causa.^[5] In 2022, he gave a TED talk on reverse engineering the human brain in the laboratory^[6] and in 2023 he became a Knight of the Order of Merit.^[7]

Pașca was born in Cluj-Napoca, in the region of Transylvania. He was raised in nearby Aiud during the last years of communism.^[8] Pașca showed early on an interest in chemistry. He set up his first science lab at the age of 11, in the basement of his parents’ house.^[9] In the final year of high school, he won a prize in the national chemistry Olympiad, earning a scholarship to attend the university of his choice in Romania. In 2001, Pașca enrolled in the Iuliu Hațieganu University of Medicine and Pharmacy at Cluj-Napoca.^[1] As a medical student, he worked with Professor Maria Dronca to explore biochemical defects in autism spectrum disorders. At the same time, he studied electrophysiology at the Max Planck Institute for Brain Research in Frankfurt in Germany under Dr Danko Nikolic. After obtaining his M.D. in 2007, Pașca went to Stanford University in early 2009 as a postdoctoral fellow with Professor Ricardo Dolmetsch. At Stanford, he developed methods to derive neurons from induced pluripotent stem cells (iPSC) and used these neural cultures to identify cellular phenotypes associated with brain disorders, including Timothy syndrome and Dravet syndrome.^{[10][11][12][13]}

In 2014, he was recruited as a tenure-track Assistant Professor at Stanford University and opened his own laboratory.^[14] He became a tenured Associate Professor in 2020 and full Professor in 2022. He was soon after named an Endowed Professor at Stanford University.^[1]

In 2023, he received a Doctor Honoris Causa (D.H.C.) from Iuliu Hatieganu Medical School in Cluj-Napoca, Romania.

His personal trajectory was described in a Quanta profile^[15] by the American journalist Claudia Dreyfus.

Pașca has two children.

Pașca’s laboratory at Stanford University explores the biological mechanisms of brain disorders using cellular models of the human brain.^[14] Pașca developed some of the early in-a-dish models of disease by deriving neurons from skin cells taken from patients with genetic forms of autism and other neurodevelopmental disorders.^[16][17] These patient neurons helped uncover the cellular defects of genetic mutations and demonstrated the promise of this novel technology.

Neural organoids

In his laboratory, Pașca introduced the use of instructive signals to develop lab-grown self-assembling three-dimensional (3D) structures called regionalized neural spheroids or organoids.^[18] This method was listed among the Key Advances in hiPSC Disease Modeling of the Last Decade by the journal Cell Stem Cell,^[19] and Organoids were named Methods of the Year in 2017 by Nature Methods.^[20] These 3D brain tissue resemble specific regions of the nervous system^[21][22] and his laboratory has maintained these cultures for over 800 days in vitro to show maturation of cells, including astrocytes, into postnatal stages. His work on astrocytes was inspired by the late Stanford neurobiologist Ben Barres.

Assembloids

Pașca has demonstrated that brain-region specific organoids can be fused to form brain assembloids and employed this preparation to study the cross-talk between cells in the developing human brain and to mimic human brain circuits in a dish.^[23] This work was listed among the Top Research Advances of 2017 by the National Institutes of Health.^[24] His lab has subsequently developed cortico-striatal^[25] and cortico-spinal-muscle assembloids.^[26]

Transplantation of organoids

In 2022, his group demonstrated the successful integration of human cortical organoids into the developing rat cerebral cortex. Human neurons displayed advanced maturation in vivo, responded to whisker stimulation and were capable of influencing the behavior of the rat in a reward task.^[27]

This work was extensively covered by the press.^{[28][29][30][31][32]} Pașca discussed the ethical implications of his work with the ethicist Insoo Hyun in a video material^[33] filmed at the Boston Science Museum.

Stanford Brain Organogenesis

In 2019, Pașca founded the Stanford Brain Organogenesis Program, which is a university wide effort to leverage technologies developed at Stanford to advance our understanding of human brain development and circuit assembly. The program includes Karl Deisseroth, Zhenan Bao, Bianxiao Cui, Michael Lin, Sarah Heilshorn and Hank Greely . Pașca serves as the Bonnie Uytengsu and Family Director. The program is also broadly sharing organoid and assembloids technologies through a free, hands-on course course that brings student from all over the world.^[34]

Teaching and public engagement

At Stanford, Pașca teaches neural development and principles of drug discovery in neuroscience. Pașca is also the co-director of the CSHL Workshop on autism spectrum disorders.^[35]

In 2022, he gave a TED talk^[36] at the Vancouver event describing the potential of human cellular models to understand disease. 

Pașca is a Chan Zuckerberg Initiative Ben Barres Investigator and a CZ BioHub Investigator. He was a New York Stem Cell Foundation Roberston Stem Cell Investigator. His researched activity gained him several awards:

• Knight of the Order of Merit, The Chancery of Orders (2023)^[7]
• Sumitomo/Sunovion Prize, International College of Neuropsychopharmacology (2023)^[37]
• Doctor Honoris Causa (D.H.C.), Hatieganu Medical School (2023)^[5]
• IBRO Dargut and Milena Kemali International Prize for Basic and Clinical Neurosciences (2022)^[38]
• Judson Daland Prize for Outstanding Achievement in Clinical Investigation, American Society of Philosophy (2021)^[39]
• Joseph Altman Award in Developmental Neuroscience (2021)^[40]
• Schizophrenia Basic Research Award (2021)^[41]
• C.J. Herrick Award in Neuroanatomy (2020)
• A.E.Bennett Award, Society of Biological Psychiatry (2018)^[42]
• Daniel H. Efron Award, American College of Neuropsychopharmacology (2018)^[43]
• Günter Blobel Award, American Society of Cell Biology (2018)^[44]
• New York Times Visionaries in Science and Medicine (2018)^[45]
• Vilcek Award for Creative Biomedical Promise (2018)^[46]
• Jordi Folch-Pi Award, American Society for Neurochemistry (2017)^[47]
• NARSAD Independent Investigator Award (2017)^[48]
• NIMH Director's BRAINS Award (2015)
• MQ Fellow Award for Transforming Mental Health (2014)^[49]
• Sammy Kuo Award (2012)^[50]
• IBRO Outstanding Research Fellow (2009)

In Romania, he was recognized as the Best Romanian student studying abroad in 2012.^[51]