Upregulation of mitochondrial calcium uniporter contributes to paraquat-induced neuropathology linked to Parkinson's disease via imbalanced OPA1 processing

Diquat exposure causes brainstem demyelination by upregulating the mitochondrial calcium uniporter

Diquat (DQ) is a widely used new herbicide that poses a great threat to the environment, ecological systems and human health. Although the central nervous system (CNS) is a sensitive target of DQ exposure, the major brain regions, pathological changes and underlying mechanisms of DQ damage to the CNS remain obscure. We demonstrated that the brainstem was the primary region where DQ damaged the CNS. DQ exposure damaged both neurons and glial cells and disrupted neurotransmitter metabolism. DQ caused brainstem demyelination, as indicated by the loss of myelin sheaths, decreased levels of myelination biomarkers, and abnormal myelin morphology. Mechanistically, the expression of the mitochondrial calcium uniporter (MCU) was increased in the DQ-exposed brainstem, and MCU knockdown mice were less sensitive to DQ-induced demyelination and CNS injury by attenuating disturbances in brain energy metabolism via the AMPK pathway. Moreover, the inhibition of MCU efficiently improved DQ-induced mitochondrial dysfunction in vitro. Overall, this study is the first to reveal that the brainstem is the key injured brain region and that demyelination is the prominent pathological feature induced by DQ exposure. The MCU is a potential therapeutic target for DQ-induced demyelination and CNS injury. These novel findings expand our understanding of DQ-induced CNS injury and offer a promising therapeutic strategy.

Decoding interaction between mitochondria and endoplasmic reticulum in ischemic myocardial injury: targeting natural medicines

Ischemic cardiomyopathy (ICM) is a special type or end stage of coronary heart disease or other irreversible ischemic myocardial injury. Inflammatory damage to coronary vessels is a crucial factor in causing stenosis or occlusion of coronary arteries, resulting in myocardial ischemia and hypoxia, but it is also an aspect of cardioprotection that is often overlooked. This review discusses the mechanisms of vascular injury during ICM, in which inflammation and oxidative stress interact and trigger cell death as the cause of coronary microvascular injury. Imbalances in endoplasmic reticulum function and mitochondrial quality control are important potential drivers of inflammation and oxidative stress. In addition, many studies have confirmed the therapeutic effects of Chinese herbal medicines and their natural monomeric components on vascular injuries. Their mitochondrial quality control and endoplasmic reticulum protection mechanisms as well as their role in combating improvements in vascular endothelial function and attenuating vascular injury are also summarized, with a perspective to provide a reference for pathologic understanding, drug research, and clinical application of ICM-associated coronary microvascular injury.

Mitochondria and myocardial ischemia/reperfusion injury: Effects of Chinese herbal medicine and the underlying mechanisms

Ischemic heart disease (IHD) is associated with high morbidity and mortality rates. Reperfusion therapy is the best treatment option for this condition. However, reperfusion can aggravate myocardial damage through a phenomenon known as myocardial ischemia/reperfusion (I/R) injury, which has recently gained the attention of researchers. Several studies have shown that Chinese herbal medicines and their natural monomeric components exert therapeutic effects against I/R injury. This review outlines the current knowledge on the pathological mechanisms through which mitochondria participate in I/R injury, focusing on the issues related to energy metabolism, mitochondrial quality control disorders, oxidative stress, and calcium. The mechanisms by which mitochondria mediate cell death have also been discussed. To develop a resource for the prevention and management of clinical myocardial I/R damage, we compiled the most recent research on the effects of Chinese herbal remedies and their monomer components.

MCU complex: Exploring emerging targets and mechanisms of mitochondrial physiology and pathology

BACKGROUND

Globally, the onset and progression of multiple human diseases are associated with mitochondrial dysfunction and dysregulation of Ca2+ uptake dynamics mediated by the mitochondrial calcium uniporter (MCU) complex, which plays a key role in mitochondrial dysfunction. Despite relevant studies, the underlying pathophysiological mechanisms have not yet been fully elucidated.

AIM OF REVIEW

This article provides an in-depth analysis of the current research status of the MCU complex, focusing on its molecular composition, regulatory mechanisms, and association with diseases. In addition, we conducted an in-depth analysis of the regulatory effects of agonists, inhibitors, and traditional Chinese medicine (TCM) monomers on the MCU complex and their application prospects in disease treatment. From the perspective of medicinal chemistry, we conducted an in-depth analysis of the structure-activity relationship between these small molecules and MCU and deduced potential pharmacophores and binding pockets. Simultaneously, key structural domains of the MCU complex in Homo sapiens were identified. We also studied the functional expression of the MCU complex in Drosophila, Zebrafish, and Caenorhabditis elegans. These analyses provide a basis for exploring potential treatment strategies targeting the MCU complex and provide strong support for the development of future precision medicine and treatments.

KEY SCIENTIFIC CONCEPTS OF REVIEW

The MCU complex exhibits varying behavior across different tissues and plays various roles in metabolic functions. It consists of six MCU subunits, an essential MCU regulator (EMRE), and solute carrier 25A23 (SLC25A23). They regulate processes, such as mitochondrial Ca2+ (mCa2+) uptake, mitochondrial adenosine triphosphate (ATP) production, calcium dynamics, oxidative stress (OS), and cell death. Regulation makes it a potential target for treating diseases, especially cardiovascular diseases, neurodegenerative diseases, inflammatory diseases, metabolic diseases, and tumors.

Double Braking Effects of Nanomedicine on Mitochondrial Permeability Transition Pore for Treating Idiopathic Pulmonary Fibrosis

Mitochondrial permeability transition pore (mPTP) opening is a key hallmark of injured type II alveolar epithelial cells (AECIIs) in idiopathic pulmonary fibrosis (IPF). Inhibiting mPTP opening in AECIIs is considered a potential IPF treatment. Herein, a "double braking" strategy on mPTP by cyclosporin A (CsA) derived ionizable lipid with 3D structure (3D-lipid) binding cyclophilin D (CypD) and siRNA downregulating mitochondrial calcium uniporter (MCU) expression is proposed for treating IPF. 3D-lipid and MCU targeting siRNA (siMCU) are co-assembled to form stable 3D-LNP/siMCU nanoparticles (NPs), along with helper lipids. In vitro results demonstrated that these NPs effectively inhibit mPTP opening by 3D-lipid binding with CypD and siRNA downregulating MCU expression, thereby decreasing damage-associated molecular patterns (DAMPs) release and suppressing epithelial-to-mesenchymal transition (EMT) process in bleomycin-induced A549 cells. In vivo results revealed that 3D-LNP/siMCU NPs effectively ameliorated collagen deposition, pro-fibrotic factors secretion, and fibroblast activation in bleomycin-induced pulmonary fibrosis (PF) mouse models. Moreover, compared to the commercial MC3-based formulation, optimized Opt-MC3/siRNA NPs with incorporating 3D-lipid as the fifth component, showed superior therapeutic efficacy against PF due to their enhanced stability and higher gene silencing efficiency. Overall, the nanomedicine containing 3D-lipid and siMCU will be a promising and potential approach for IPF treatment.

INTERSPECIES ORGANOIDS REVEAL HUMAN-SPECIFIC MOLECULAR FEATURES OF DOPAMINERGIC NEURON DEVELOPMENT AND VULNERABILITY

The disproportionate expansion of telencephalic structures during human evolution involved tradeoffs that imposed greater connectivity and metabolic demands on midbrain dopaminergic neurons. Despite the central role of dopaminergic neurons in human-enriched disorders, molecular specializations associated with human-specific features and vulnerabilities of the dopaminergic system remain unexplored. Here, we establish a phylogeny-in-a-dish approach to examine gene regulatory evolution by differentiating pools of human, chimpanzee, orangutan, and macaque pluripotent stem cells into ventral midbrain organoids capable of forming long-range projections, spontaneous activity, and dopamine release. We identify human-specific gene expression changes related to axonal transport of mitochondria and reactive oxygen species buffering and candidate cis- and trans-regulatory mechanisms underlying gene expression divergence. Our findings are consistent with a model of evolved neuroprotection in response to tradeoffs related to brain expansion and could contribute to the discovery of therapeutic targets and strategies for treating disorders involving the dopaminergic system.

The expression profile of brain-derived exosomal miRNAs reveals the key molecules responsible for spontaneous motor function recovery in a rat model with permanent middle cerebral artery occlusion

The analysis of alterations in the expression and functionality of brain-derived exosomal miRNAs within ischemic stroke lesions provides significant insights into the mechanisms that contribute to disease recovery. We assessed spontaneous motor function in a rat model of permanent middle cerebral artery occlusion (pMCAO) using motor function scores and magnetic resonance imaging (MRI). Brain-derived exosomes from the infarcted brain tissue of the animal model were extracted and high-throughput sequencing of them was performed followed by bioinformatics analysis for differentially expressed miRNAs target genes. Real-time quantitative polymerase chain reaction (qRT-PCR) was used to measure expression levels of differentially expressed miRNAs at various time points. The oxygen-glucose deprivation (OGD) model was established to investigate gene function through the assessment of cell proliferation and apoptosis using EdU proliferation and JC-1 apoptosis assay. The rat model demonstrated a spontaneous recovery of motor function and a reduction in cerebral infarction area from day 1 to day 14 post-operation. Over the course of the recovery period, miR-24-3p, miR-129-1-3p, and miR-212-5p maintained consistent expression levels, reaching their peak on the initial day following surgery. In the cell model, EdU detection indicated that miR-129-1-3p promoted cellular proliferation, while JC-1 detection revealed its suppressive impact on cellular apoptosis. The current research findings indicated the presence of spontaneous motor function restoration in a rat model of ischemic stroke. MiR-24-3p, miR-129-1-3p, and miR-212-5p were identified as pivotal genes in this recovery process, with miR-129-1-3p potentially influencing the restoration of spontaneous motor function in ischemic stroke through the regulation of neuronal proliferation and apoptosis.

Mitochondrial calcium uniporter complex: Unveiling the interplay between its regulators and calcium homeostasis

The mitochondrial calcium uniporter complex (MCUc), serving as the specific channel for calcium influx into the mitochondrial matrix, is integral to calcium homeostasis and cellular integrity. Given its importance, ongoing research spans various disease models to understand the properties of the MCUc in pathophysiological contexts, but reported a different conclusion. Therefore, this review delves into the profound connection between MCUc-mediated calcium transients and cellular signaling pathways, mitochondrial dynamics, metabolism, and cell death. Additionally, we shed light on the recent advancements concerning the structural intricacies and auxiliary components of the MCUc in both resting and activated states. Furthermore, emphasis is placed on novel extrinsic and intrinsic regulators of the MCUc and their therapeutic implications across a spectrum of diseases. Meanwhile, we employed molecular docking simulations and identified candidate traditional Chinese medicine components with potential binding sites to the MCUc, potentially offering insights for further research on MCUc modulation.

The tightest self-assembled ruthenium metal-organic framework combined with proximity hybridization for ultrasensitive electrochemiluminescence analysis of paraquat

Metal-organic frameworks (MOFs), as porous materials, have great potential for exploring high-performance electrochemiluminescence (ECL) probes. However, the constrained applicability of MOFs in the realm of ECL biosensing is primarily attributed to their inadequate water stability, which consequently impairs the overall ECL efficiency. Herein, we developed a competitive ECL biosensor based on a novel tightest structural ruthenium-based organic framework emitter combining the proximity hybridization-induced catalytic hairpin assembly (CHA) strategy and the quenching effect between the Ru-MOF and ferrocene for detecting paraquat (PQ). Through a simple hydrothermal synthesis strategy, ruthenium and 2,2'-bipyrimidine (bpm) are head-to-head self-assembled to obtain a novel tightest structural Ru-MOF. Due to the metal-ligand charge-transfer (MLCT) effect between ruthenium and the bpm ligand and the connectivity between the internal chromophore units, the Ru-MOF exhibits strong ECL emissions. Meanwhile, the coordination-driven Ru-MOF utilizes strong metal-organic coordination bonds as building blocks, which effectively solves the problem of serious leakage of chromophores caused by water solubility. The sensitive analysis of PQ is realized in the range of 1 pg/mL to 1 ng/mL with a detection limit of 0.352 pg/mL. The tightest structural Ru-MOF driven by the coordination of ruthenium and bridging ligands (2,2'-bipyrimidine, bpm) provides new horizons for exploring high-performance MOF-based ECL probes for quantitative analysis of biomarkers.

Advancements in Genetic and Biochemical Insights: Unraveling the Etiopathogenesis of Neurodegeneration in Parkinson's Disease

Parkinson's disease (PD) is the second most prevalent neurodegenerative movement disorder worldwide, which is primarily characterized by motor impairments. Even though multiple hypotheses have been proposed over the decades that explain the pathogenesis of PD, presently, there are no cures or promising preventive therapies for PD. This could be attributed to the intricate pathophysiology of PD and the poorly understood molecular mechanism. To address these challenges comprehensively, a thorough disease model is imperative for a nuanced understanding of PD's underlying pathogenic mechanisms. This review offers a detailed analysis of the current state of knowledge regarding the molecular mechanisms underlying the pathogenesis of PD, with a particular emphasis on the roles played by gene-based factors in the disease's development and progression. This study includes an extensive discussion of the proteins and mutations of primary genes that are linked to PD, including α-synuclein, GBA1, LRRK2, VPS35, PINK1, DJ-1, and Parkin. Further, this review explores plausible mechanisms for DAergic neural loss, non-motor and non-dopaminergic pathologies, and the risk factors associated with PD. The present study will encourage the related research fields to understand better and analyze the current status of the biochemical mechanisms of PD, which might contribute to the design and development of efficacious and safe treatment strategies for PD in future endeavors.

Empagliflozin targets Mfn1 and Opa1 to attenuate microglia-mediated neuroinflammation in retinal ischemia and reperfusion injury

BACKGROUND

Neuroinflammation and mitochondrial dysfunction play crucial roles in retinal ischemia and reperfusion (IR) injury. Recent studies have identified mitochondrial function as a promising target for immunomodulation. Empagliflozin (EMPA), an anti-diabetic drug, has exhibited great potential as both an anti-inflammatory agent and a protector of mitochondrial health. This study aimed to assess the therapeutic efficacy of EMPA in retinal IR injury.

METHODS

To evaluate the protective effects of EMPA, the drug was injected into the vitreous body of mice post-retinal IR. Single-cell RNA sequencing (scRNA-seq) analysis was conducted to uncover the underlying mechanisms, and the results were further validated through in vivo and in vitro experiments.

RESULTS

EMPA effectively protected retinal ganglion cells (RGCs) from IR injury by attenuating local retinal inflammation. The scRNA-seq analysis revealed that EMPA downregulated the nucleotide-binding domain and leucine-rich repeat containing protein 3 (NLRP3) signaling pathway and restored mitochondrial dynamics by upregulating the expression of mitochondrial fusion-related genes, Mitofusin 1 (Mfn1) and optic atrophy 1 (Opa1). These findings were further corroborated by Western blotting. In vitro experiments provided additional insights, demonstrating that EMPA suppressed lipopolysaccharide (LPS)-induced cell inflammation and NLRP3 inflammasome activation. Moreover, EMPA enhanced mitochondrial fusion, neutralized mitochondrial reactive oxygen species (mtROS), and restored mitochondrial membrane potential (MMP) in BV2 microglia. Notably, genetic ablation of Mfn1 or Opa1 abolished the anti-inflammatory effects of EMPA.

CONCLUSIONS

Our findings highlight the positive contribution of Mfn1 and Opa1 to the anti-inflammatory therapeutic effect of EMPA. By restoring mitochondrial dynamics, EMPA effectively mitigates microglia-mediated neuroinflammation and prevents RGC loss in retinal IR injury.

Multifaceted roles of mitochondrial dysfunction in diseases: from powerhouses to saboteurs

The fact that mitochondria play a crucial part in energy generation has led to the nickname "powerhouses" of the cell being applied to them. They also play a significant role in many other cellular functions, including calcium signalling, apoptosis, and the creation of vital biomolecules. As a result, cellular function and health as a whole can be significantly impacted by mitochondrial malfunction. Indeed, malignancies frequently have increased levels of mitochondrial biogenesis and quality control. Adverse selection exists for harmful mitochondrial genome mutations, even though certain malignancies include modifications in the nuclear-encoded tricarboxylic acid cycle enzymes that generate carcinogenic metabolites. Since rare human cancers with mutated mitochondrial genomes are often benign, removing mitochondrial DNA reduces carcinogenesis. Therefore, targeting mitochondria offers therapeutic options since they serve several functions and are crucial to developing malignant tumors. Here, we discuss the various steps involved in the mechanism of cancer for which mitochondria plays a significant role, as well as the role of mitochondria in diseases other than cancer. It is crucial to understand mitochondrial malfunction to target these organelles for therapeutic reasons. This highlights the significance of investigating mitochondrial dysfunction in cancer and other disease research.

Calcium Homeostasis, Transporters, and Blockers in Health and Diseases of the Cardiovascular System

Calcium is a highly positively charged ionic species. It regulates all cell types' functions and is an important second messenger that controls and triggers several mechanisms, including membrane stabilization, permeability, contraction, secretion, mitosis, intercellular communications, and in the activation of kinases and gene expression. Therefore, controlling calcium transport and its intracellular homeostasis in physiology leads to the healthy functioning of the biological system. However, abnormal extracellular and intracellular calcium homeostasis leads to cardiovascular, skeletal, immune, secretory diseases, and cancer. Therefore, the pharmacological control of calcium influx directly via calcium channels and exchangers and its outflow via calcium pumps and uptake by the ER/SR are crucial in treating calcium transport remodeling in pathology. Here, we mainly focused on selective calcium transporters and blockers in the cardiovascular system.