Nanomedicinal delivery approaches for therapeutic siRNA

RNA interference (RNAi) has been named as “breakthrough technology” in 2002 by Science magazine. In a short timespan this technology has conquered life sciences and numerous therapeutic approaches and is now well underway to become an important pilier of novel class of RNA based therapeutics. This mini-review focuses on nanomedicinal delivery approaches for siRNA that have shown promise with small molecules, and have recently been applied with the aim to deliver siRNA to humans for treatment of disease.     

The fall and rise of pharmacology – (Re-)defining the discipline?

Pharmacology is an integrative discipline that originated from activities, now nearly 7000 years old, to identify therapeutics from natural product sources. Research in the 19th Century that focused on the Law of Mass Action (LMA) demonstrated that compound effects were dose-/concentration-dependent eventually leading to the receptor concept, now a century old, that remains the key to understanding disease causality and drug action. As pharmacology evolved in the 20th Century through successive biochemical, molecular and genomic eras, the precision in understanding receptor function at the molecular level increased and while providing important insights, led to an overtly reductionistic emphasis. This resulted in the generation of data lacking physiological context that ignored the LMA and was not integrated at the tissue/whole organism level. As reductionism became a primary focus in biomedical research, it led to the fall of pharmacology. However, concerns regarding the disconnect between basic research efforts and the approval of new drugs to treat 21st Century disease tsunamis, e.g., neurodegeneration, metabolic syndrome, etc. has led to the reemergence of pharmacology, its rise, often in the semantic guise of systems biology. Against a background of limited training in pharmacology, this has resulted in issues in experimental replication with a bioinformatics emphasis that often has a limited relationship to reality. The integration of newer technologies within a pharmacological context where research is driven by testable hypotheses rather than technology, together with renewed efforts in teaching pharmacology, is anticipated to improve the focus and relevance of biomedical research and lead to novel therapeutics that will contain health care costs.     

The complex etiology of multiple sclerosis

Multiple sclerosis is a demyelinating disease which is presumed to be a consequence of infiltrating lymphocytes autoreactive to myelin proteins. This is substantiated by several lines of clinical evidence and supported by correlative studies in preclinical models. The development of new therapeutics for MS has been guided by this perspective; however, the pathogenesis of MS has proven to be quite complex as observations exist which question the role of autoreactive lymphocytes in the etiology of MS. In addition the current immunomodulatory therapeutics do not prevent most patients from progressing into more serious forms of the disease. The development of truly transformational therapeutics for MS will likely require a broad assault that expands beyond the concept of MS being an autoimmune disease.     

Transgenic animals as drug factories: a new source of recombinant protein therapeutics

The utility of transgenic animal bioreactors for the production of complex therapeutic proteins is based on lower production costs, higher production capacities and safer, pathogen free products. Until gene therapy becomes broadly efficacious, transgenic-derived therapeutics are the most attractive alternative for prophylactic, replacement therapy in genetic disorders, such as haemophilia. Many other disease states need short-term treatment of significant amounts of recombinant proteins that could be made amply available from transgenic animal sources. In addition, transgenic animals will provide an ideal expression system for the production of a portfolio of alternative therapeutics for patient populations developing inhibiting antibodies, for enhanced bioactivity, or for increased plasma clearance times. The FDA approval of a transgenic-derived therapeutic is still pending, but a review of Phase I & II data from antithrombin III from goat milk is encouraging, and companies are continuing to add potential therapeutics to their product pipeline.     

Structural requirements of heparin and related molecules to exert a multitude of anti-inflammatory activities

Chronic inflammatory diseases are common and still remain a therapeutic challenge for both efficacy and safety reasons. Hence, novel therapeutics addressing these issues would for example improve treatment of severe diseases such as psoriasis, rheumatoid arthritis, inflammatory bowel disease and multiple sclerosis. Inappropriate leukocyte homing to the affected compartments is a common feature of these diseases. Heparin and related polysaccharides have been shown to interfere with leukocyte homing through a variety of effects distinct from their anticoagulant properties. In this review, data on heparin as an anti-inflammatory agent are presented. In addition, structure-activity requirements for the anti-inflammatory properties of heparin are discussed, which should aid the drug development based on structurally modified heparin or other sulfated carbohydrates for treatment of inflammatory diseases.     

The cutting-edge technologies of siRNA delivery and their application in clinical trials

siRNA therapeutics allows precise regulation of disease specific gene expression to treat various diseases. Although gene silencing approaches using siRNA therapeutics shows some promising results in the treatment of gene-related diseases, the practical applications has been limited by problems such as inefficient in vivo delivery to target cells and nonspecific immune responses after systemic or local administration. To overcome these issues, various in vivo delivery platforms have been introduced. Here we provide an overview for three different platform technologies for the in vivo delivery of therapeutic siRNAs (siRNA–GalNAc conjugate, SAMiRNA technology, and LNP-based delivery method) and their applications in the treatment of various diseases. In addition, a brief introduction to some rare diseases and mechanisms of siRNA therapeutics-mediated treatment is described.     

Strictly Standardized Mean Difference,Standardized Mean Difference and Classical t-test for the Comparison of Two Groups

Statistical significance or p-value of t-test for testing mean difference has been widely used for the comparison of two groups. However, because of many issues that the statistical significance has, it has been intensively criticized in medical and social sciences. Consequently, effect sizes such as Cohen’s d have been proposed as an alternative to statistical significance. Recently, strictly standardized mean difference (SSMD) has been proposed for the comparison of two groups with applications in data analysis in high-throughput screening experiments. In this article, from a theoretical basis, I explore the relationships between SSMD, standardized mean difference, and p-value of classical t-test for comparing two groups. The relationships among these measures hint that SSMD may serve as an alternative to statistical significance in medical sciences and as an alternative to traditional effect sizes in social sciences.     

Parkinson's Disease Therapeutics: New Developments and Challenges Since the Introduction of Levodopa

The demonstration that dopamine loss is the key pathological feature of Parkinson''s disease (PD), and the subsequent introduction of levodopa have revolutionalized the field of PD therapeutics. This review will discuss the significant progress that has been made in the development of new pharmacological and surgical tools to treat PD motor symptoms since this major breakthrough in the 1960s. However, we will also highlight some of the challenges the field of PD therapeutics has been struggling with during the past decades. The lack of neuroprotective therapies and the limited treatment strategies for the nonmotor symptoms of the disease (ie, cognitive impairments, autonomic dysfunctions, psychiatric disorders, etc.) are among the most pressing issues to be addressed in the years to come. It appears that the combination of early PD nonmotor symptoms with imaging of the nigrostriatal dopaminergic system offers a promising path toward the identification of PD biomarkers, which, once characterized, will set the stage for efficient use of neuroprotective agents that could slow down and alter the course of the disease.     

High-throughput electronic biology: mining information for drug discovery

The vast range of in silico resources that are available in life sciences research hold much promise towards aiding the drug discovery process. To fully realize this opportunity, computational scientists must consider the practical issues of data integration and identify how best to apply these resources scientifically. In this article we describe in silico approaches that are driven towards the identification of testable laboratory hypotheses; we also address common challenges in the field. We focus on flexible, high-throughput techniques, which may be initiated independently of 'wet-lab' experimentation, and which may be applied to multiple disease areas. The utility of these approaches in drug discovery highlights the contribution that in silico techniques can make and emphasizes the need for collaboration between the areas of disease research and computational science.     

The preclinical discovery of amyotrophic lateral sclerosis drugs

Introduction: Amyotrophic lateral sclerosis (ALS), also referred to as Lou Gehrig's disease, is characterized by the progressive loss of cells in the brain and spinal cord that leads to debilitation and death in 3 - 5 years. Only one therapeutic drug, riluzole, has been approved for ALS and this drug improves survival by 2 - 3 months. The need for new therapeutics that can postpone or slow the progression of the motor deficits and prolong survival is still a strong unmet medical need. Areas covered: Although there are a number of drugs currently in clinical trials for ALS, this review provides an overview of the most promising biological targets and preclinical strategies that are currently being developed and deployed. The list of targets for ALS was compiled from a variety of websites including individual companies that have ALS programs and include those from the author's experience. Expert opinion: Progress is being made in the identification of possible new therapeutics for ALS with recent efforts in understanding the genetic causes of the disease, susceptibility factors and the development of additional preclinical animal models. However, many challenges remain in the identification of new ALS therapeutics including: the use of relevant biomarkers, the need for an earlier diagnosis of the disease and additional animal models. Multiple strategies need to be tested in the clinic in order to determine what will be effective in patients.     

Web services in the life sciences

Web services provide a standard way of publishing applications and data sources over the internet, enabling mass dissemination of knowledge. In the life sciences, the web-service approach is seen as being a road to standardizing the multitude of tools available from different providers. In this article, we present an overview of the technology (focusing on life-science applications), we list the currently available service providers and we discuss advanced issues raised by the concept.     

Multiple sclerosis: where will we be in 2020?

The past decade has seen a surge of research interest in multiple sclerosis and an accelerated expansion of investigative efforts into multiple sclerosis therapeutics. Investigators have continued dissecting the complex immunological perturbations that may contribute to the disease and made major advances in understanding the genetics of multiple sclerosis. This article addresses current investigative issues and offers predictions about where the understanding and treatment of multiple sclerosis may stand at the end of the 21st century's second decade.     

siRNA and the lung: research tool or therapeutic drug?

Oligonucleotide-based therapeutics have been hailed as 'the next great wave of the biotechnology revolution' starting with antisense oligonucleotides (ASOs) nearly 20 years ago to RNA interference (RNAi) currently. Is RNAi just the latest research tool or does it have real potential as a therapeutic drug modality? As a research tool, it is evident that RNAi has revolutionized the biological sciences by allowing selective silencing of messenger RNA (mRNA) expression. With the advent of the postgenomic era, RNAi offers a therapeutic platform on which to identify potential picomolar active drug candidates to any target, including those that are conventionally undruggable. In this review, we will discuss the progress made in developing RNAi therapeutics for the treatment of respiratory diseases.     

Harnessing metabolomics for nutrition research

Comprehensive analytical technologies are rapidly becoming a cornerstone of modern nutritional sciences. Two of these technologies, mass spectrometry (MS) and nuclear magnetic resonance (NMR), have proven highly informative for the global analysis of metabolites, commonly referred to as metabolomics. Metabolomics provides a powerful approach to study small molecules in order to better understand the implications and subtle perturbations in metabolism triggered by nutrients. By studying how dietary molecules can modulate the metabolome, researchers have begun to elucidate the molecular pathways by which nutrients affect health and disease, expand the current state of knowledge regarding how inter-individual variability contributes to differences in nutrient metabolism, and develop novel avenues of research for nutritional sciences. Although metabolomics has been more commonly used to study disease states, its use in the nutritional sciences is gaining momentum. The current review is written for the clinical researcher wishing to incorporate metabolomics into dietary intervention studies. This review will highlight the importance and benefit of identifying biomarkers that accurately reflect changes in nutrient intake and metabolism, and present numerous issues that can introduce variability into a dataset and confound a study's biological interpretation, including sample population demographics, the biological specimen selected, diurnal variation, collection methods, and sample storage parameters. Considering these important areas at the experimental design stage will ensure that metabolomics provides a comprehensive and accurate assessment of the molecular impact of a dietary intervention.     

The neonatal Fc receptor,FcRn, as a target for drug delivery and therapy

Immunoglobulin G (IgG)-based drugs are arguably the most successful class of protein therapeutics due in part to their remarkably long blood circulation. This arises from IgG interaction with the neonatal Fc receptor, FcRn. FcRn is the central regulator of IgG and albumin homeostasis throughout life and is increasingly being recognized as an important player in autoimmune disease, mucosal immunity, and tumor immune surveillance. Various engineering approaches that hijack or disrupt the FcRn-mediated transport pathway have been devised to develop long-lasting and non-invasive protein therapeutics, protein subunit vaccines, and therapeutics for treatment of autoimmune and infectious disease. In this review, we highlight the diverse biological functions of FcRn, emerging therapeutic opportunities, as well as the associated challenges of targeting FcRn for drug delivery and disease therapy.     

Translational experimental therapeutics: The translation of laboratory-based discovery into disease-related therapy

In the past decade, there has been an increasing emphasis on laboratory-based translational research. This has led to significant scientific advances in our understanding of disease mechanisms and in the development of novel approaches to therapy such as gene therapy, RNA interference, and stem cells. However, the translation of these remarkable scientific achievements into new and effective disease-modifying therapies has lagged behind these scientific accomplishments. We use the term "translational experimental therapeutics" to describe the pathway between the discovery of a basic disease mechanism or novel therapeutic approach and its translation into an effective treatment for patients with a specific disease. In this article, we review the components of this pathway, and discuss issues that might impede this process. Only by optimizing this pathway can we realize the full therapeutic potential of current scientific discoveries and translate the astounding advances that have been accomplished in the laboratory into effective treatments for our patients.     

Druggable targets and targeted drugs: enhancing the development of new therapeutics

The advent of functional genomics, proteomics, chemi-informatics, and other systems-based scientific approaches have raised expectations of novel targets for drug discovery and design. Similarly, advances in materials sciences and biomolecular chemistries raised the prospects of highly targeted therapeutics that maximize efficacy while minimizing systemic toxicity. In spite of these advances, the gross measure of approvable drug output is declining, with only 17 new chemical entities approved by the FDA in 2007. This is in the face of high levels of R&D expenditures in both public and private sectors, and suggests that new, integrative approaches are needed in order to maximally exploit the rapidly expanding knowledge of potential drug and disease targets. The convergence of novel druggable targets with new chemical entities that can be specifically targeted to disease-causing sites and genes represents one means of creating highly efficacious and specific therapies. The approaches that are needed to facilitate such convergence include merging computational methods, systems biology, and gene-linked categorization of diseases with the use of appropriate drug delivery vehicles.     

Antibody-based technologies for target discovery

Antibodies have proven to be exquisite investigation tools in the field of life sciences. They also constitute one of the oldest and most successful biological products for diagnostics and therapeutics. This review investigates the current use of antibodies in target discovery. To address this topic in a larger context, established and emerging technologies that are expected to contribute to target discovery will first be examined. These technologies include: mass spectroscopic analysis of proteins, protein-protein interaction and other network analysis approaches, as well as protein and antibody arrays. The potential of antibody engineering and the ANTIBIOMIX technology will then be discussed; antibody therapeutics, however, will not be examined.     

Web resources facilitate drug discovery in treatment of COVID-19

The infectious disease Coronavirus 2019 (COVID-19) continues to cause a global pandemic and, thus, the need for effective therapeutics remains urgent. Global research targeting COVID-19 treatments has produced numerous therapy-related data and established data repositories. However, these data are disseminated throughout the literature and web resources, which could lead to a reduction in the levels of their use. In this review, we introduce resource repositories for the development of COVID-19 therapeutics, from the genome and proteome to antiviral drugs, vaccines, and monoclonal antibodies. We briefly describe the data and usage, and how they advance research for therapies. Finally, we discuss the opportunities and challenges to preventing the pandemic from developing further.     

Toxicity of repeated intravenous injection of gene therapeutics for X-CGD in mice

We made gene therapeutics for X-chronic granulomatous disease (CGD) by transducing murine bone marrow-derived stem cells with MT-gp91 retrovirus and evaluated possible toxicity in mice as a prerequisite for human clinical trials. Male C57BL/6 mice were injected intravenously with gene therapeutics for X-CGD twice at an interval of two weeks at 5 x 10(7) cells/kg and sacrificed 2 weeks after the last administration. Significant changes noted in gene therapeutics for X-CGD-treated animals were an increase in white blood cell counts and a slight decrease in albumin/globulin ratio. The red pulp hyperplasia in the spleen accompanied with an increase in organ weight was considered to result from the accumulation of gene therapeutics for X-CGD, bone marrow-derived stem cells, in the spleen. No anti-gp91 antibody was detected in the sera collected from the animals treated with gene therapeutics for X-CGD. No integration of gp91 DNA from retroviral vector was detected in chromosomal DNA of gonads in animals dosed with the test substance, indicating no potential of genomic integration. In conclusion, the repeated dose of gene therapeutics for X-CGD exerted no toxicity. The splenic red pulp hyperplasia and the increase observed in white blood cell counts and in spleen weights were considered as pharmacological changes induced by the treatment.