Myoglobin in Brown Adipose Tissue: A Multifaceted Player in Thermogenesis

A versatile delivery vehicle for cellular oxygen and fuels or metabolic sensor? A review and perspective on the functions of myoglobin

A canonical view of the primary physiological function of myoglobin (Mb) is that it is an oxygen (O2) storage protein supporting mitochondrial oxidative phosphorylation, especially as the tissue O2 partial pressure (Po2) drops and Mb off-loads O2. Besides O2 storage/transport, recent findings support functions for Mb in lipid trafficking and sequestration, interacting with cellular glycolytic metabolites such as lactate (LAC) and pyruvate (PYR), and "ectopic" expression in some types of cancer cells and in brown adipose tissue (BAT). Data from Mb knockout (Mb-/-) mice and biochemical models suggest additional metabolic roles for Mb, especially regulation of nitric oxide (NO) pools, modulation of BAT bioenergetics, thermogenesis, and lipid storage phenotypes. From these and other findings in the literature over many decades, Mb's function is not confined to delivering O2 in support of oxidative phosphorylation but may serve as an O2 sensor that modulates intracellular Po2- and NO-responsive molecular signaling pathways. This paradigm reflects a fundamental change in how oxidative metabolism and cell regulation are viewed in Mb-expressing cells such as skeletal muscle, heart, brown adipocytes, and select cancer cells. Here, we review historic and emerging views related to the physiological roles for Mb and present working models illustrating the possible importance of interactions between Mb, gases, and small-molecule metabolites in regulation of cell signaling and bioenergetics.

The globins of cyanobacteria and green algae: An update

The globin superfamily of proteins is ancient and diverse. Regular assessments based on the increasing number of available genome sequences have elaborated on a complex evolutionary history. In this review, we present a summary of a decade of advances in characterising the globins of cyanobacteria and green algae. The focus is on haem-containing globins with an emphasis on recent experimental developments, which reinforce links to nitrogen metabolism and nitrosative stress response in addition to dioxygen management. Mention is made of globins that do not bind haem to provide an encompassing view of the superfamily and perspective on the field. It is reiterated that an effort toward phenotypical and in-vivo characterisation is needed to elucidate the many roles that these versatile proteins fulfil in oxygenic photosynthetic microbes. It is also proposed that globins from oxygenic organisms are promising proteins for applications in the biotechnology arena.

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

Ischemic strokes, prevalence and impactful, underscore the necessity of advanced research models closely resembling human physiology. Our study utilizes nonhuman primates (NHPs) to provide a detailed exploration of ischemic stroke, integrating neuroimaging data, behavioral outcomes, and serum proteomics to elucidate the complex interplay of factors involved in stroke pathophysiology. We observed a consistent pattern in infarct volume, peaking at 1-month postmiddle cerebral artery occlusion (MCAO) and then stabilized. This pattern was strongly correlated to notable changes in motor function and working memory performance. Using diffusion tensor imaging (DTI), we detected significant alterations in fractional anisotropy (FA) and mean diffusivity (MD) values, signaling microstructural changes in the brain. These alterations closely correlated with the neurological and cognitive deficits that we observed, highlighting the sensitivity of DTI metrics in stroke assessment. Behaviorally, the monkeys exhibited a reliance on their unaffected limb for compensatory movements, a common response to stroke impairment. This adaptation, along with consistent DTI findings, suggests a significant impact of stroke on motor function and spatial perception. Proteomic analysis through MS/MS functional enrichment identified two distinct groups of proteins with significant changes post-MCAO. Notably, MMP9, THBS1, MB, PFN1, and YWHAZ were identified as potential biomarkers and therapeutic targets for ischemic stroke. Our results underscore the complex nature of stroke and advocate for an integrated approach, combining neuroimaging, behavioral studies, and proteomics, for advancing our understanding and treatment of this condition.

Photodynamic Therapy for Atherosclerosis

Atherosclerosis, which currently contributes to 31% of deaths globally, is of critical cardiovascular concern. Current diagnostic tools and biomarkers are limited, emphasizing the need for early detection. Lifestyle modifications and medications form the basis of treatment, and emerging therapies such as photodynamic therapy are being developed. Photodynamic therapy involves a photosensitizer selectively targeting components of atherosclerotic plaques. When activated by specific light wavelengths, it induces localized oxidative stress aiming to stabilize plaques and reduce inflammation. The key advantage lies in its selective targeting, sparing healthy tissues. While preclinical studies are encouraging, ongoing research and clinical trials are crucial for optimizing protocols and ensuring long-term safety and efficacy. The potential combination with other therapies makes photodynamic therapy a versatile and promising avenue for addressing atherosclerosis and associated cardiovascular disease. The investigations underscore the possibility of utilizing photodynamic therapy as a valuable treatment choice for atherosclerosis. As advancements in research continue, photodynamic therapy might become more seamlessly incorporated into clinical approaches for managing atherosclerosis, providing a blend of efficacy and limited invasiveness.