Hosted by the College of Engineering and School of Mechanical Engineering

Abstract

Physical exercise is well known to enhance brain health, including promoting neurogenesis, even in later stages of life. The prevailing central dogma posits that muscle-released biochemicals enter the brain and mediate neurogenesis. However, the mechanisms by which these chemicals exert their effects have remained elusive for decades. There is increasing evidence that most living cells are contractile and mechanosensitive. We have previously shown that neurons generate tension, without which they fail to function [1,2]. In the brain, astrocytes (integral components of the blood-brain barrier), are the first responders to muscle-released biochemicals during exercise, suggesting that they may relay muscle-derived signals to neuronal cells.

We will discuss evidence that muscle-released factors increase astrocyte contractility. Activated astrocytes, in turn, release factors that enhance neuronal contractility and electrical activity. These changes promote the differentiation of neural stem cells into new neurons [3].

For centuries, brain function has been viewed as being determined primarily by biochemical and electrical activities. Our findings identify cellular mechanics as a third, largely unexplored element influencing brain function, providing a more comprehensive understanding of brain health and disease.

[1] Siechen, et al. PNAS, 2009, 106(31).

[2] Joy, et al. PNAS 2023 120(52)

[3] Lee, et al. Neuroscience. 2023 April 01; 515.

Biography

Professor Saif was born in Dhaka, Bangladesh. He earned BS and MS degrees in Civil Engineering from Bangladesh University of Engineering and Technology and Washington State University, followed by a PhD in Theoretical and Applied Mechanics at Cornell University. He conducted postdoctoral research on MEMS at Cornell Electrical Engineering before joining the Department of Mechanical Science and Engineering at the University of Illinois Urbana-Champaign (UIUC) in 1997. His interdisciplinary work spans mechanics of neurons and cardiac cells, tumor microenvironments, biohybrid robotics, and nanomaterials. Professor Saif is a fellow of the American Society of Mechanical Engineers and the American Association for the Advancement of Science. He received the 2018 Koiter Medal from American Society of Mechanical Engineers and the 2020 Engineering Science Medal from the Society of Engineering Science. In 2024, he was elected to the National Academy of Engineering of USA. He was endowed with the Grainger Distinguished Chair in 2025 in the Grainger College of Engineering, UIUC.