Nanotechnology-Based Drug Delivery Strategies to Repair the Mitochondrial Function in Neuroinflammatory and Neurodegenerative Diseases

Unlocking the Mitochondria for Nanomedicine-based Treatments: Overcoming Biological Barriers, Improving Designs, and Selecting Verification Techniques

Enhanced targeting approaches will support the treatment of diseases associated with dysfunctional mitochondria, which play critical roles in energy generation and cell survival. Obstacles to mitochondria-specific targeting include the presence of distinct biological barriers and the need to pass through (or avoid) various cell internalization mechanisms. A range of studies have reported the design of mitochondrially-targeted nanomedicines that navigate the complex routes required to influence mitochondrial function; nonetheless, a significant journey lies ahead before mitochondrially-targeted nanomedicines become suitable for clinical use. Moving swiftly forward will require safety studies, in vivo assays confirming effectiveness, and methodologies to validate mitochondria-targeted nanomedicines' subcellular location/activity. From a nanomedicine standpoint, we describe the biological routes involved (from administration to arrival within the mitochondria), the features influencing rational design, and the techniques used to identify/validate successful targeting. Overall, rationally-designed mitochondria-targeted-based nanomedicines hold great promise for precise subcellular therapeutic delivery.

Monoclonal antibody therapy for Alzheimer's disease focusing on intracerebral targets

Alzheimer's disease (AD) is one of the most common neurodegenerative diseases. Due to the complexity of the disorder and the presence of the blood-brain barrier (BBB), its drug discovery and development are facing enormous challenges, especially after several failures of monoclonal antibody (mAb) trials. Nevertheless, the Food and Drug Administration's approval of the mAb aducanumab has ushered in a new day. As we better understand the disease's pathogenesis and identify novel intracerebral therapeutic targets, antibody-based therapies have advanced over the past few years. The mAb drugs targeting β-amyloid or hyperphosphorylated tau protein are the focus of the current research. Massive neuronal loss and glial cell-mediated inflammation are also the vital pathological hallmarks of AD, signaling a new direction for research on mAb drugs. We have elucidated the mechanisms by which AD-specific mAbs cross the BBB to bind to targets. In order to investigate therapeutic approaches to treat AD, this review focuses on the promising mAbs targeting intracerebral dysfunction and related strategies to cross the BBB.

The role of mitochondrial dynamics in disease

Mitochondria are multifaceted and dynamic organelles regulating various important cellular processes from signal transduction to determining cell fate. As dynamic properties of mitochondria, fusion and fission accompanied with mitophagy, undergo constant changes in number and morphology to sustain mitochondrial homeostasis in response to cell context changes. Thus, the dysregulation of mitochondrial dynamics and mitophagy is unsurprisingly related with various diseases, but the unclear underlying mechanism hinders their clinical application. In this review, we summarize the recent developments in the molecular mechanism of mitochondrial dynamics and mitophagy, particularly the different roles of key components in mitochondrial dynamics in different context. We also summarize the roles of mitochondrial dynamics and target treatment in diseases related to the cardiovascular system, nervous system, respiratory system, and tumor cell metabolism demanding high-energy. In these diseases, it is common that excessive mitochondrial fission is dominant and accompanied by impaired fusion and mitophagy. But there have been many conflicting findings about them recently, which are specifically highlighted in this view. We look forward that these findings will help broaden our understanding of the roles of the mitochondrial dynamics in diseases and will be beneficial to the discovery of novel selective therapeutic targets.

Mitochondria in Huntington's disease: implications in pathogenesis and mitochondrial-targeted therapeutic strategies

Huntington's disease is a genetic disease caused by expanded CAG repeats on exon 1 of the huntingtin gene located on chromosome 4. Compelling evidence implicates impaired mitochondrial energetics, altered mitochondrial biogenesis and quality control, disturbed mitochondrial trafficking, oxidative stress and mitochondrial calcium dyshomeostasis in the pathogenesis of the disorder. Unfortunately, conventional mitochondrial-targeted molecules, such as cysteamine, creatine, coenzyme Q10, or triheptanoin, yielded negative or inconclusive results. However, future therapeutic strategies, aiming to restore mitochondrial biogenesis, improving the fission/fusion balance, and improving mitochondrial trafficking, could prove useful tools in improving the phenotype of Huntington's disease and, used in combination with genome-editing methods, could lead to a cure for the disease.

Mitochondria-associated cellular senescence mechanisms: Biochemical and pharmacological perspectives

Initially, endosymbiotic relation of mitochondria and other cellular compartments had been continued mutually. However, that evolutionary adaptation impaired because of the deterioration of endosymbiotic crosstalk due to aging and several pathological consequences in cellular redox status are seen, such as deterioration in redox integrity of mitochondria, interfered inter-organelle redox signaling and inefficient antioxidant response element mediated gene expression. Although the dysfunction of mitochondria is known to be a classical pattern of senescence, it is unresolved that why dysfunctional mitochondria is the core of senescence-associated secretory phenotype (SASP). Redox impairment and SASP-related disease development are generally together with weaken immunity. Impaired mitochondrial redox integrity and its ineffectiveness in immunity control render elders to be more prone to age-related diseases. As senotherapeutic agents, senolytics remove senescent cells whilst senomorphics/senostatics inhibits the secretion of SASP. Senotherapeutics and the novel approaches for ameliorating SASP-related unfavorable effects are recently thought to be promising ways as mitochondria-targeted gerotherapeutic options.

Nanopharmacology as a new approach to treat neuroinflammatory disorders

Neuroinflammation, a complex process involving the activation of microglia, astrocytes, and other immune cells in the brain, plays a role in neurodegeneration and psychiatric disorders. Current therapeutic strategies for neuroinflammation are limited, necessitating the development of improved approaches. Nanopharmacology offers unprecedented opportunities to access and treat neuroinflammatory disorders at the brain level. Nanoscaffolds can target specific cells or tissues and protect drugs from degradation or elimination, making them ideal candidates for treating neurodegenerative and psychiatric diseases. Recent advancements in nanoparticle development have enabled the targeting of microglia, astrocytes, and other immune cells in the brain, reducing neuroinflammation and protecting neurons from injury. Nanoparticles targeting specific neurons have also been developed. Clinical trials are in progress to evaluate the safety and efficacy of nano drugs for treating neuroinflammatory, neurodegenerative, and psychiatric diseases. The successful development of these nanodrugs holds immense promise for treating these devastating and increasingly prevalent conditions. On the other hand, several limitations and unanswered questions remain. First, the long-term effects of nanoparticles on the brain need to be thoroughly investigated to ensure their safety. Second, optimizing the targeting and delivery of nanoparticles to specific brain regions remains a challenge. Understanding the complex interplay between nanoparticles and the brain's immune system is crucial for developing effective nanotherapies. Despite these limitations, nanopharmacology presents a transformative approach to treating neuroinflammatory disorders. Future research should address the aforementioned limitations and further elucidate the mechanisms of nanoparticle-mediated therapy. The successful development of safe and effective nanodrugs can revolutionize the treatment of neuroinflammatory disorders, alleviating the suffering of millions.

The immune system as a driver of mitochondrial disease pathogenesis: a review of evidence

BACKGROUND

Genetic mitochondrial diseases represent a significant challenge to human health. These diseases are extraordinarily heterogeneous in clinical presentation and genetic origin, and often involve multi-system disease with severe progressive symptoms. Mitochondrial diseases represent the most common cause of inherited metabolic disorders and one of the most common causes of inherited neurologic diseases, yet no proven therapeutic strategies yet exist. The basic cell and molecular mechanisms underlying the pathogenesis of mitochondrial diseases have not been resolved, hampering efforts to develop therapeutic agents.

MAIN BODY

In recent pre-clinical work, we have shown that pharmacologic agents targeting the immune system can prevent disease in the Ndufs4(KO) model of Leigh syndrome, indicating that the immune system plays a causal role in the pathogenesis of at least this form of mitochondrial disease. Intriguingly, a number of case reports have indicated that immune-targeting therapeutics may be beneficial in the setting of genetic mitochondrial disease. Here, we summarize clinical and pre-clinical evidence suggesting a key role for the immune system in mediating the pathogenesis of at least some forms of genetic mitochondrial disease.

CONCLUSIONS

Significant clinical and pre-clinical evidence indicates a key role for the immune system as a significant in the pathogenesis of at least some forms of genetic mitochondrial disease.

Mitochondria-targeted senotherapeutic interventions

Healthy aging is the art of balancing a delicate scale. On one side of the scale, there are the factors that make life difficult with aging, and on the other side are the products of human effort against these factors. The most important factors that make the life difficult with aging are age-related disorders. Developing senotherapeutic strategies may bring effective solutions for the sufferers of age-related disorders. Mitochondrial dysfunction comes first in elucidating the pathogenesis of age-related disorders and presenting appropriate treatment options. Although it has been widely accepted that mitochondrial dysfunction is a common characteristic of cellular senescence, it still remains unclear why dysfunctional mitochondria occupy a central position in the development senescence-associated secretory phenotype (SASP) related to age-related disorders. Mitochondrial dysfunction and SASP-related disease progression are closely interlinked to weaken immunity which is a common phenomenon in aging. A group of substances known as senotherapeutics targeted to senescent cells can be classified into two main groups: senolytics (kill senescent cells) and senomorphics/senostatics (suppress their SASP secretions) in order to extend health lifespan and potentially lifespan. As mitochondria are also closely related to the survival of senescent cells, using either mitochondria-targeted senolytic or redox modulator senomorphic strategies may help us to solve the complex problems with the detrimental consequences of cellular senescence. Killing of senescent cells and/or ameliorate their SASP-related negative effects are currently considered to be effective mitochondria-directed gerotherapeutic approaches for fighting against age-related disorders.