Role of Mitochondria-ER Contact Sites in Mitophagy

Functional transformation of macrophage mitochondria in cardiovascular diseases

Mitochondria are pivotal in the modulation of macrophage activation, differentiation, and survival. Furthermore, macrophages are instrumental in the onset and progression of cardiovascular diseases. Hence, it is imperative to investigate the role of mitochondria within macrophages in the context of cardiovascular disease. In this review, we provide an updated description of the origin and classification of cardiac macrophages and also focused on the relationship between macrophages and mitochondria in cardiovascular diseases with respect to (1) proinflammatory or anti-inflammatory macrophages, (2) macrophage apoptosis, (3) macrophage pyroptosis, and (4) macrophage efferocytosis. Clarifying the relationship between mitochondria and macrophages can aid the exploration of novel therapeutic strategies for cardiovascular disease.

The Janus-faced functions of Apolipoproteins L in membrane dynamics

The functions of human Apolipoproteins L (APOLs) are poorly understood, but involve diverse activities like lysis of bloodstream trypanosomes and intracellular bacteria, modulation of viral infection and induction of apoptosis, autophagy, and chronic kidney disease. Based on recent work, I propose that the basic function of APOLs is the control of membrane dynamics, at least in the Golgi and mitochondrion. Together with neuronal calcium sensor-1 (NCS1) and calneuron-1 (CALN1), APOL3 controls the activity of phosphatidylinositol-4-kinase-IIIB (PI4KB), involved in both Golgi and mitochondrion membrane fission. Whereas secreted APOL1 induces African trypanosome lysis through membrane permeabilization of the parasite mitochondrion, intracellular APOL1 conditions non-muscular myosin-2A (NM2A)-mediated transfer of PI4KB and APOL3 from the Golgi to the mitochondrion under conditions interfering with PI4KB-APOL3 interaction, such as APOL1 C-terminal variant expression or virus-induced inflammatory signalling. APOL3 controls mitophagy through complementary interactions with the membrane fission factor PI4KB and the membrane fusion factor vesicle-associated membrane protein-8 (VAMP8). In mice, the basic APOL1 and APOL3 activities could be exerted by mAPOL9 and mAPOL8, respectively. Perspectives regarding the mechanism and treatment of APOL1-related kidney disease are discussed, as well as speculations on additional APOLs functions, such as APOL6 involvement in adipocyte membrane dynamics through interaction with myosin-10 (MYH10).

Increased NAD+ levels protect female mouse reproductive system against zearalenone-impaired glycolysis, lipid metabolism, antioxidant capacity and inflammation

The reproductive system is a primary target organ for zearalenone (ZEN, a widespread fusarium mycotoxin) to exert its toxic effects, including decreased antioxidant capacity and aggravated inflammatory response. These ZEN-induced reproductive abnormalities are partially caused by the declining levels of nicotinamide adenine dinucleotide (NAD+), which results in an imbalance in lipid/glucose metabolism. Accordingly, the present study aimed to investigate whether supplements of nicotinamide mononucleotide (NMN, a NAD+ precursor) in female mice could protect against ZEN-induced reproductive toxicity. In this study, thirty female mice were randomly divided into three groups that were intragastrically administered with i) 0.5% DMSO (the Ctrl group), ii) 3 mg/(kg bw.d) ZEN (the ZEN group), or iii) ZEN + 500 mg/(kg bw.d) NMN (the ZEN/NMN group) for two weeks. The results revealed that, compared with the Ctrl group, animals exposed to ZEN exhibited reproductive toxicity, such as decreased antioxidant capacity and aggravated inflammatory response in reproductive tissues. These effects were strongly correlated with lower activities in key glycolytic enzymes (e.g., ALDOA and PGK), but increased expressions in key lipid-synthesis genes (e.g., LPIN1 and ATGL). These changes contribute to lipid accumulation, specifically for diacylglycerols (DAGs). Furthermore, these ZEN-induced changes were linked with disturbed NAD+ synthesis/degradation, and subsequently decreased NAD+ levels. Notably, NMN supplements in mice protected against these ZEN-induced reproductive abnormalities by boosting NAD+ levels. Herein, the present findings demonstrate that potential strategies to enhance NAD+ levels can protect against ZEN-induced reproductive toxicity.

Calcium channelopathies in neurodegenerative disorder: an untold story of RyR and SERCA

INTRODUCTION

Recent neuroscience breakthroughs have shed light on the sophisticated relationship between calcium channelopathies and movement disorders, exposing a previously undiscovered tale focusing on the Ryanodine Receptor (RyR) and the Sarco/Endoplasmic Reticulum Calcium ATPase (SERCA). Calcium signaling mainly orchestrates neural communication, which regulates synaptic transmission and total network activity. It has been determined that RyR play a significant role in managing neuronal functions, most notably in releasing intracellular calcium from the endoplasmic reticulum.

AREAS COVERED

It highlights the involvement of calcium channels such as RyR and SERCA in physiological and pathophysiological conditions.

EXPERT OPINION

Links between RyR and SERCA activity dysregulation, aberrant calcium levels, motor and cognitive dysfunction have brought attention to the importance of RyR and SERCA modulation in neurodegenerative disorders. Understanding the obscure function of these proteins will open up new therapeutic possibilities to address the underlying causes of neurodegenerative diseases. The unreported RyR and SERCA narrative broadens the understanding of calcium channelopathies in movement disorders and calls for more research into cutting-edge therapeutic approaches.