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Lotje D De Witte, MD, PhD

img_Lotje D De Witte
ASSISTANT CLINICAL PROFESSOR | Psychiatry
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Microglia
Microglia cells are the resident immune cells of the brain. From animal studies it is known that microglia are not only involved in initiating and controlling inflammation in the central nervous system (CNS), but that they are also crucial for neurodevelopment and neuronal functioning in adulthood. In her lab, Dr. de Witte studies whether one of these functions is affected in psychiatric disorders. She has set up several human microglia models, including the isolation of these cells from post-mortem brain tissue, generating them from induced pluripotent stems cells and monocytes. Using these models she compares microglia from patients and controls at the phenotypic and functional level. In addition, she studies whether specific genetic risk factors for neurodevelopmental disorders alter microglia functioning.
The role of the immune system in psychiatric disorders
An association between the immune system and psychiatric disorders, such as schizophrenia, bipolar disorder and autism, is becoming more and more evident. Targeting the immune system is therefore one of the major focuses for finding novel drug targets. However, it is still largely unknown how immune processes are involved in these diseases at the molecular level.
Auto-antibodies
Antibodies that bind to synaptic proteins can cause autoimmune encephalitis and this can lead to prominent psychiatric symptoms. A clear example is anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis, which is caused by auto-antibodies to one of the subunits of the NMDA receptor. Dr. de Witte studies whether subgroups of patients with psychiatric disorders may have an underlying autoimmune disease caused by neuronal auto-antibodies. Her studies on blood samples of patients with schizophrenia or bipolar disorders indicate that the presence of these auto-antibodies is very rare. She is now involved in validating these findings in cerebrospinal fluid.
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Publications

Selected Publications

Prenatal inflammation and postpartum anxiety: Findings from a prospective pregnancy cohort in New York City. Carly Kaplan, Floriana Milazzo, Anna Suleri, Frederieke Gigase, Whitney Lieb, Lot D. de Witte, Veerle Bergink, Anna Sophie Rommel. Journal of Affective Disorders

Navigating Human Astrocyte Differentiation: Direct and Rapid One-Step Differentiation of Induced Pluripotent Stem Cells to Functional Astrocytes Supporting Neuronal Network Development. Imke M.E. Schuurmans, Annika Mordelt, Marta Guevara-Ferrer, Katrin Linda, Denise Duineveld, Sofia Puvogel, Marina P. Hommersom, Nicky Scheefhals, Lisa Rahm, Emma Dyke, Gijs Jan Scholten, Caroline Knorz, Carlos Gonzalez Jimenez, Noelle van Egmond, Astrid Oudakker, Chantal Bijnagte-Schoenmaker, Hans van Bokhoven, Wei Wei, Samuel Hofmann, Sabine Jung-Klawitter, Sandra Mojica-Perez, Jack Parent, Lidia Carotenuto, Sarah Weckhuysen, Nadine Maas, Ype Elgersma, Eline van de Ven, Dirk Lefeber, Anita Lygeroudi, Helga E. de Vries, Luc Jordi, Magdalini Polymenidou, Teresa Mitchell-Garcia, Iulia Dragan, Amalia Dolga, Lot D. de Witte, Clara D.M. van Karnebeek, James Ellis, Alejandro Garanto, Nael Nadif Kasri. GLIA

Postpartum Psychosis and Bipolar Disorder: Review of Neurobiology and Expert Consensus Statement on Classification. Veerle Bergink, Schahram Akbarian, Nancy Byatt, Prabha S. Chandra, Nicole Cirino, Paola Dazzan, Lot De Witte, Arianna Di Florio, Clare Dolman, Ian Jones, Astrid Kamperman, Behrang Mahjani, Samantha Meltzer-Brody, Trine Munk-Olsen, Sarah Nagle-Yang, Lauren M. Osborne, Natalie Rasgon, Thalia Robakis, Harish Thippeswamy, Simone N. Vigod, Jennifer L. Payne. Biological Psychiatry

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Physicians and scientists on the faculty of the Icahn School of Medicine at Mount Sinai often interact with pharmaceutical, device, biotechnology companies and other outside entities to improve patient care, develop new therapies and achieve scientific breakthroughs. In order to promote an ethical and transparent environment for conducting research, providing clinical care and teaching, Mount Sinai requires that salaried faculty inform the School of their outside financial relationships.

Dr. De Witte did not report having any of the following types of financial relationships with industry and other outside entities during 2025 and/or 2026: consulting, scientific advisory board, industry-sponsored lectures, service on Board of Directors, participation on industry-sponsored committees, equity ownership valued at greater than 5% of a publicly traded company or any value in a privately held company. Please note that this information may differ from information posted on corporate sites due to timing or classification differences.

Mount Sinai's faculty policies relating to faculty collaboration with industry are posted on our website. Patients may wish to ask their physician about the activities they perform for companies.