Myoglobin in Brown Adipose Tissue: A Multifaceted Player in Thermogenesis

Abstract

Brown adipose tissue (BAT) plays an important role in energy homeostasis by generating heat from chemical energy via uncoupled oxidative phosphorylation. Besides its high mitochondrial content and its exclusive expression of the uncoupling protein 1, another key feature of BAT is the high expression of myoglobin (MB), a heme-containing protein that typically binds oxygen, thereby facilitating the diffusion of the gas from cell membranes to mitochondria of muscle cells. In addition, MB also modulates nitric oxide (NO•) pools and can bind C16 and C18 fatty acids, which indicates a role in lipid metabolism. Recent studies in humans and mice implicated MB present in BAT in the regulation of lipid droplet morphology and fatty acid shuttling and composition, as well as mitochondrial oxidative metabolism. These functions suggest that MB plays an essential role in BAT energy metabolism and thermogenesis. In this review, we will discuss in detail the possible physiological roles played by MB in BAT thermogenesis along with the potential underlying molecular mechanisms and focus on the question of how BAT–MB expression is regulated and, in turn, how this globin regulates mitochondrial, lipid, and NO• metabolism. Finally, we present potential MB-mediated approaches to augment energy metabolism, which ultimately could help tackle different metabolic disorders.

Comprehensive Assessment of Ischemic Stroke in Nonhuman Primates: Neuroimaging, Behavioral, and Serum Proteomic Analysis

“…Elevated serum MB levels post-MCAO were observed, consistent with increase noted in human stroke patients (Di Angelantonio et al, 2005) and acute stroke monkey models (Guo et al, 2019). This sustained elevation aligns with clinical findings associating high MMP9 levels in ischemic stroke patients with increased risks of severe disability or death, underscoring its prognostic significance (Sato et al, 2005); Aboouf et al, 2023). PFN1, an actin-binding protein involved in various physiological processes, showed elevated levels post-MCAO.…”

Comprehensive Assessment of Ischemic Stroke in Nonhuman Primates: Neuroimaging, Behavioral, and Serum Proteomic Analysis

“…38 This sustained elevation aligns with clinical findings associating high MMP9 levels in ischemic stroke patients with increased risks of severe disability or death, underscoring its prognostic significance. 39,40 PFN1, an actinbinding protein involved in various physiological processes, showed elevated levels post-MCAO. Present in almost all tissues and cells, 41 PFN1 is crucial for multiple physiological processes, including cell migration, 42 vascular permeability, 43 angiogenesis, 44 and oxidative stress.…”

Photodynamic Therapy for Atherosclerosis

“…Oxidative stress occurs when there is an imbalance between the product of reactive oxygen species (ROS) and the body's capability to neutralize them. Reactive oxygen species can contribute to the inflammation and damage of arterial walls, a key feature of atherosclerosis [63]. Additionally, myoglobin may be involved in the recruitment and activation of immune cells, such as macrophages, which play a role in the inflammatory response associated with atherosclerosis.…”