Sam Horng, MD, PhD
img_Sam Horng
ASSISTANT PROFESSOR | Neurology, Multiple Sclerosis
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Research Topics
Blood-Brain Barrier, Brain Imaging, Chemokines, Cytokines, Demyelination, Immunology, Multiple Sclerosis, Neuro-degeneration/protection, Neurobiology, Neurology, Neuroscience
Multi-Disciplinary Training Area
Neuroscience [NEU]
Multiple Sclerosis
The Horng Laboratory

Clinical disability in multiple sclerosis (MS) is driven by immune cell infiltration into the CNS parenchy-ma. Understanding the mechanisms by which CNS barrier cells regulate immune cell activation and en-try during this infiltrative process may identify novel therapeutic strategies for MS and other CNS auto-immune diseases.

During CNS inflammation, immune cells traffic from the blood through a two-barrier structure termed the neurovascular unit. While many have focused on entry through the first barrier, a specialized en-dothelial wall known as the blood-brain barrier, less is known about how immune cells interact with the second barrier, a layer of endfoot processes extending from specialized cells called astrocytes, a barrier referred to as the glia limitans. In MS lesions, immune cells circulate within the space between the first and second barriers, a compartment termed the perivascular space. Within this space, immune cells interact with the astrocyte endfeet and potentially receive signals that prime them for autoimmune attack.

The Horng Laboratory is interested in identifying and characterizing the signaling pathways between astrocytes and immune cells within the perivascular spaces. We are testing the hypothesis that this cross-talk regulates immune cell function prior to CNS entry and induces functional differentiation in both cell types which contributes to both the acute phase of CNS inflammation and more chronic processes of neurodegeneration.

MD, Harvard Medical School

BA, Columbia University

PhD, Massachusetts Institute of Technology

Internship, Internal Medicine, Yale New Haven Hospital

Residency, Neurology, Mount Sinai School of Medicine

Fellowship, Neuroimmunology, Multiple Sclerosis, Mount Sinai School of Medicine


K08 Mentored Clinical Scientist Research Career Development Award

National Institute of Neurological Diseases and Stroke


Research Fellowship in Neuroscience

Leon Levy Foundation


Arnold P. Gold Foundation’s Humanism and Excellence in Teaching Award

Department of Medical Education at the Icahn School of Medicine at Mount Sinai


F30 Predoctoral NRSA Fellowship

National Institute of Neurological Diseases and Stroke

Physicians and scientists on the faculty of the Icahn School of Medicine at Mount Sinai often interact with pharmaceutical, device and biotechnology companies 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 relationships with such companies.

Dr. Horng did not report having any of the following types of financial relationships with industry during 2022 and/or 2023: 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.