Validation of the mitochondrial delivery of vitamin B1 to enhance ATP production using SH-SY5Y cells, a model neuroblast

Activation of Mitochondrial Oxygen Consumption Rate by Delivering Coenzyme Q10 to Mitochondria of Rat Skeletal Muscle Cell (L6)

Numerous mitochondria are present in skeletal muscle cells. Muscle disease and aging impair mitochondrial functioning in the skeletal muscle. However, there have been few reports of therapeutic intervention via drug delivery to mitochondria owing to methodological difficulties. We surmised that mitochondrial activation is associated with improved skeletal muscle function. In this study, we attempted to activate the mitochondrial respiratory capacity in rat skeletal muscle cells (L6 cells) by delivering Coenzyme Q10 (CoQ10), a mitochondrial functional activator, to mitochondria using MITO-Porter, a nanoparticle that facilitates mitochondria-targeted drug delivery. Cellular uptake was confirmed by measuring the amount of fluorescence-modified MITO-Porter taken up by cells using flow cytometry. Intracellular dynamics of MITO-Porter was observed using confocal laser scanning microscopy. Mitochondrial function was assessed by measuring the mitochondrial oxygen consumption rate using an extracellular flux analyzer. The results indicated MITO-Porter-assisted delivery of CoQ10 to the mitochondria activated mitochondrial respiratory capacity in L6 cells. We believe that our results indicate the possibility of skeletal muscle therapy using mitochondrial drug delivery.

Decreasing Intracellular Entropy by Increasing Mitochondrial Efficiency and Reducing ROS Formation-The Effect on the Ageing Process and Age-Related Damage

A hypothesis is presented to explain how the ageing process might be influenced by optimizing mitochondrial efficiency to reduce intracellular entropy. Research-based quantifications of entropy are scarce. Non-equilibrium metabolic reactions and compartmentalization were found to contribute most to lowering entropy in the cells. Like the cells, mitochondria are thermodynamically open systems exchanging matter and energy with their surroundings-the rest of the cell. Based on the calculations from cancer cells, glycolysis was reported to produce less entropy than mitochondrial oxidative phosphorylation. However, these estimations depended on the CO2 concentration so that at slightly increased CO2, it was oxidative phosphorylation that produced less entropy. Also, the thermodynamic efficiency of mitochondrial respiratory complexes varies depending on the respiratory state and oxidant/antioxidant balance. Therefore, in spite of long-standing theoretical and practical efforts, more measurements, also in isolated mitochondria, with intact and suboptimal respiration, are needed to resolve the issue. Entropy increases in ageing while mitochondrial efficiency of energy conversion, quality control, and turnover mechanisms deteriorate. Optimally functioning mitochondria are necessary to meet energy demands for cellular defence and repair processes to attenuate ageing. The intuitive approach of simply supplying more metabolic fuels (more nutrients) often has the opposite effect, namely a decrease in energy production in the case of nutrient overload. Excessive nutrient intake and obesity accelerate ageing, while calorie restriction without malnutrition can prolong life. Balanced nutrient intake adapted to needs/activity-based high ATP requirement increases mitochondrial respiratory efficiency and leads to multiple alterations in gene expression and metabolic adaptations. Therefore, rather than overfeeding, it is necessary to fine-tune energy production by optimizing mitochondrial function and reducing oxidative stress; the evidence is discussed in this paper.

The impact of, and expectations for, lipid nanoparticle technology: From cellular targeting to organelle targeting

The success of mRNA vaccines against COVID-19 has enhanced the potential of lipid nanoparticles (LNPs) as a system for the delivery of mRNA. In this review, we describe our progress using a lipid library to engineer ionizable lipids and promote LNP technology from the viewpoints of safety, controlled biodistribution, and mRNA vaccines. These advancements in LNP technology are applied to cancer immunology, and a potential nano-DDS is constructed to evaluate immune status that is associated with a cancer-immunity cycle that includes the sub-cycles in tumor microenvironments. We also discuss the importance of the delivery of antigens and adjuvants in enhancing the cancer-immunity cycle. Recent progress in NK cell targeting in cancer immunotherapy is also introduced. Finally, the impact of next-generation DDS technology is explained using the MITO-Porter membrane fusion-based delivery system for the organelle targeting of the mitochondria. We introduce a successful example of the MITO-Porter used in a cell therapeutic strategy to treat cardiomyopathy.

RNA Delivery to Mitochondria

The approval of mRNA-containing lipid nanoparticles (LNPs) for use in a vaccine against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the clinical utility of RNA-loaded nanocapsules has stimulated a rapid acceleration in research in this area. The development of mRNA-containing LNP vaccines has been rapid, not only because of regulatory adjustments, but also to the advances made in nucleic acid delivery as the result of efforts by many basic researchers. RNA functions, not only in the nucleus and cytoplasm, but also in mitochondria, which have their own genomic apparatus. Mitochondrial diseases caused by mutations or defects in the mitochondrial genome, mitochondrial DNA (mtDNA) are intractable and are mainly treated symptomatically, but gene therapy as a fundamental treatment is expected to soon be a reality. To realize this therapy, a drug delivery system (DDS) that delivers nucleic acids including RNA to mitochondria is required, but efforts in this area have been limited compared to research targeting the nucleus and cytoplasm. This contribution provides an overview of mitochondria-targeted gene therapy strategies and discusses studies that have attempted to validate mitochondria-targeted RNA delivery therapies. We also present the results of 'RNA delivery to mitochondria' based on the use of our mitochondria-targeted DDS (MITO-Porter) that was developed in our laboratory.

Development and challenges of antimicrobial peptide delivery strategies in bacterial therapy: A review

The escalating global prevalence of antimicrobial resistance poses a critical threat, prompting concerns about its impact on public health. This predicament is exacerbated by the acute shortage of novel antimicrobial agents, a scarcity attributed to the rapid surge in bacterial resistance. This review delves into the realm of antimicrobial peptides, a diverse class of compounds ubiquitously present in plants and animals across various natural organisms. Renowned for their intrinsic antibacterial activity, these peptides provide a promising avenue to tackle the intricate challenge of bacterial resistance. However, the clinical utility of peptide-based drugs is hindered by limited bioavailability and susceptibility to rapid degradation, constraining efforts to enhance the efficacy of bacterial infection treatments. The emergence of nanocarriers marks a transformative approach poised to revolutionize peptide delivery strategies. This review elucidates a promising framework involving nanocarriers within the realm of antimicrobial peptides. This paradigm enables meticulous and controlled peptide release at infection sites by detecting dynamic shifts in microenvironmental factors, including pH, ROS, GSH, and reactive enzymes. Furthermore, a glimpse into the future reveals the potential of targeted delivery mechanisms, harnessing inflammatory responses and intricate signaling pathways, including adenosine triphosphate, macrophage receptors, and pathogenic nucleic acid entities. This approach holds promise in fortifying immunity, thereby amplifying the potency of peptide-based treatments. In summary, this review spotlights peptide nanosystems as prospective solutions for combating bacterial infections. By bridging antimicrobial peptides with advanced nanomedicine, a new therapeutic era emerges, poised to confront the formidable challenge of antimicrobial resistance head-on.

Nanomedicine for Maternal and Fetal Health

Conception, pregnancy, and childbirth are complex processes that affect both mother and fetus. Thus, it is perhaps not surprising that in the United States alone, roughly 11% of women struggle with infertility and 16% of pregnancies involve some sort of complication. This presents a clear need to develop safe and effective treatment options, though the development of therapeutics for use in women's health and particularly in pregnancy is relatively limited. Physiological and biological changes during the menstrual cycle and pregnancy impact biodistribution, pharmacokinetics, and efficacy, further complicating the process of administration and delivery of therapeutics. In addition to the complex pharmacodynamics, there is also the challenge of overcoming physiological barriers that impact various routes of local and systemic administration, including the blood-follicle barrier and the placenta. Nanomedicine presents a unique opportunity to target and sustain drug delivery to the reproductive tract and other relevant organs in the mother and fetus, as well as improve the safety profile and minimize side effects. Nanomedicine-based approaches have the potential to improve the management and treatment of infertility, obstetric complications, and fetal conditions.

Development of a Mitochondrial Targeting Lipid Nanoparticle Encapsulating Berberine

Delivering drugs to mitochondria, the main source of energy in neurons, can be a useful therapeutic strategy for the treatment of neurodegenerative diseases. Berberine (BBR), an isoquinoline alkaloid, acts on mitochondria and is involved in mechanisms associated with the normalization and regulation of intracellular metabolism. Therefore, BBR has attracted considerable interest as a possible therapeutic drug for neurodegenerative diseases. While BBR has been reported to act on mitochondria, there are few reports on the efficient delivery of BBR into mitochondria. This paper reports on the mitochondrial delivery of BBR using a lipid nanoparticle (LNP), a "MITO-Porter" that targets mitochondria, and its pharmacological action in Neuro2a cells, a model neuroblastoma. A MITO-Porter containing encapsulated BBR (MITO-Porter (BBR)) was prepared. Treatment with MITO-Porter (BBR) increased the amount of BBR that accumulated in mitochondria compared with a treatment with naked BBR. Treatment with MITO-Porter (BBR) resulted in increased ATP production in Neuro2a cells, which are important for maintaining life phenomena, compared with treatment with naked BBR. Treatment with MITO-Porter (BBR) also increased the level of expression of mitochondrial ubiquitin ligase (MITOL), which is involved in mitochondrial quality control. Our findings indicate that increasing the accumulation of BBR into mitochondria is important for inducing enhanced pharmacological actions. The use of this system has the potential for being important in terms of the regulation of the metabolic mechanism of mitochondria in nerve cells.

Innovative cancer nanomedicine based on immunology, gene editing, intracellular trafficking control

The recent rapid progress in the area of drug delivery systems (DDS) has opened a new era in medicine with a strong linkage to understanding the molecular mechanisms associated with cancer survival. In this review, we summarize new cancer strategies that have recently been developed based on our DDS technology. Cancer immunotherapy will be improved based on the concept of the cancer immunity cycle, which focuses on dynamic interactions between various types of cancer and immune cells in our body. The new technology of genome editing will also be discussed with reference to how these new DDS technologies can be used to introduce therapeutic cargoes into our body. Lastly, a new organelle, mitochondria will be the focus of creating a new cancer treatment strategy by a MITO-Porter which can deliver macromolecules directly to mitochondria of cancer cells via a membrane fusion approach and the impact of controlled intracellular trafficking will be discussed.

Recent advances in delivering RNA-based therapeutics to mitochondria

INTRODUCTION

After the emergence of lipid nanoparticles (LNP) containing therapeutic mRNA as vaccines for use against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the clinical usefulness of nucleic acid-encapsulated LNPs is now a fact. In addition to the nucleus and cytoplasm, mitochondria, which have their own genome, are a site where nucleic acids function in the cell. Gene therapies targeting mitochondria are expected to pave the way for the next generation of therapies.

AREAS COVERED

Methods for delivering nucleic acids to mitochondria are needed in order to realize such innovative therapies. However, only a few reports on delivery systems targeting mitochondria have appeared. In this review, we summarize the current state of research on RNA-based therapeutics targeted to mitochondria, with emphasis on mitochondrial RNA delivery therapies and on therapies that involve the use of mitochondrial genome editing devices.

EXPERT OPINION

We hope that this review article will focus our attention to this area of research, stimulate more interest in this field of research, and lead to the development of mitochondria-targeted nucleic acid medicine. It has the potential to become a major weapon against urgent and unknown diseases, including SARS-CoV-2 infections.