Uncoupling proteins as a therapeutic target for the development of new era drugs against neurodegenerative disorder

Mitochondrial uncoupling proteins (UCP) are a part of the large family of mitochondrial solute carriers (SLC25s), concentrated in the inner mitochondrial membrane that carries protons from intermembrane space to the matrix. Further, some UCPs are also involved in the transportation of the fatty acid anions and catalyzed the proton transport by fatty acid cycling across the membrane. Out of the 5 UCPs, UCP 2, 4, and 5 are localized in the central nervous system (CNS), and alteration within the expression of these UCPs results in neuronal dysfunction and, ultimately, death of neurons. UCPs play a vital role in regulating mitochondrial membrane potential, preventing reactive oxygen species (ROS) production, alteration in neuronal activity, and the regulation of calcium homeostasis that ultimately results in the prevention of neuronal loss. These changes in mitochondria impact the function and survival of neurons playing a critical role in the progression of neurodegenerative diseases, particularly Alzheimer's disease (AD) and Parkinson's disease (PD). Additionally, UCP2 regulates the microglia response towards neuroinflammation by modulating microglia's M1 and M2 phenotypes. These microglia cells are further involved in regulating inflammatory response and synaptic functions. Moreover, UCP2, 4, and 5 are ubiquitously present in all brain regions that negatively regulate ROS production and inflammation, leading to the prevention of neuronal cell death. Increased ROS production is a common symptom reported in neurodegenerative diseases that affect several pathways concerned with neuronal death, either apoptosis or autophagy. These accumulating evidence suggested UCPs as a possible therapeutic target for the management of neurodegenerative diseases.