Natural products are useful sources in the search for biochemical probes and drug leads because of their unique biological activities. However, synthetic studies or functional analyses of polycyclic complex natural products or conjugated lipids (e.g., glycolipids) are often hampered because of their synthesis and handling are challenging. On the basis of rational designs, synthetic studies, and chemical modifications, natural products need to be optimized to more potent compounds with improved activities, selectivities and/or physical properties. We have been synthesizing natural products and their derivatives for the elucidation of their biological mechanisms and discovery of drug leads. This review describes three topics for developing functional compounds derived from natural products for prospective involvement in pharmaceutical research: 1) direct construction of the ergot alkaloid scaffold by palladium catalyzed domino cyclization of amino allenes; 2) identification of novel sphingosine kinase inhibitors through a structure-activity relationship study of jaspine B; and 3) design, synthesis and biological evaluation of novel CD1d glycolipid ligands containing modified lipid moieties.
Chronic heart failure is the final stage of such heart diseases as hypertension, cardiomyopathy, and myocardial infarction. Since the incidence of heart failure has increased in recent decades, heart failure is now a major public health problem in developed countries, including Japan. Recently, some studies have demonstrated that natural products, used as nutritional supplements, play an important role in preventing the development of heart failure in animal studies. In our previous study, we showed that curcumin, a natural polyphenol compound derived from Curcuma longa, exhibits therapeutic potency against heart failure. To establish the pharmacological therapeutic value of curcumin in heart failure, we have investigated the translational research of curcumin. This report reviews our basic studies and clinical trials using curcumin therapeutically to prevent heart failure, as well as the possibility of clinical applications of curcumin.
The latest chemical management policies require toxicological evaluation of marketed but untested chemicals. Furthermore, in Europe, for animal welfare reasons sales of cosmetics and raw materials for which animal experiments were conducted were totally banned, in 2013. Responding to these regulatory trends, a strong demand exists to develop new in vitro test methods and to improve in silico prediction models for safety assessments. In recent years, the development of adverse outcome pathways (AOPs) has been actively promoted in the Organisation for Economic Co-operation and Development (OECD). Since it is difficult to replace a particular in vivo animal test with a single in vitro test method or in silico prediction model, integrated approaches to testing and assessment (IATA) have been studied based on AOP information. With regard to skin sensitization, several in vitro test methods that measure key events of AOP have been established, and integrated strategies using in vitro tests have been examined using AOP. Currently, numerous AOPs are under development for a wide range of complex toxicity endpoints in the OECD AOP program. The AOPs are expected to contribute to the development of many accurate in vitro test methods and to establish IATA as well as to evaluate safety in humans of many substances, including household chemicals, food-related chemicals, cosmetics, and pharmaceuticals.
The Organisation for Economic Co-operation and Development (OECD) has initiated the adverse outcome pathway (AOP) Development Program in which the concept of AOP is applied to evaluate the safety of molecules such as chemicals. This program aims to assist regulatory needs and construct a knowledge base by accumulating AOP case studies. AOP consists of a molecular initiating event (MIE) as the initiating event of the pathway; key events (KEs) as the events themselves, such as cellular-molecular interactions; and adverse outcome (AO), such as signaling transduction-induced toxicity, as adverse events. KEs are extracted as important events at various levels, such as the molecular, cellular, tissue, organ, individual, and species levels; measurement of KEs and key event relationships (KERs), including mechanisms, plausibility, species differences, and empirical support information, are gathered. The development status of the AOP relating to histone deacetylase inhibition-induced testicular toxicity, currently being reviewed by the OECD, has been introduced. The AOP describing malignancies by Wnt ligand stimulation and Wnt signaling activation using gene expression network analysis-based mechanisms in molecular pathway elucidation has been suggested.
Because the liver is the primary target organ for chemicals and pharmaceuticals, evaluation of these substances' liver toxicity is of critical importance. New evaluation methods without animal testing (i.e., in vitro and/or in silico) are eagerly anticipated, both for animal welfare and for decreasing cost. Also, the importance of mechanistic interpretation of the output derived from non-animal testing has been increasing. Accordingly, we investigated the potential for evaluating liver toxicity by applying the adverse outcome pathway (AOP) concept using gene set enrichment analysis (GSEA) from gene expression (GEx) data. A case study targeting hepatocellular fatty degeneration (HFD) is reported and discussed. We first identified the events detectable in an in vitro system by comparing the GEx data from the rat primary hepatocyte (in vitro) and rat liver (in vivo) treated with a chemical with the ability to induce HFD as one of the phenotypes in a 28-day repeated-dose toxicity test. Then, the scores based on GSEA were calculated after establishing the gene sets for each event leading to HFD. As a result, the mechanistic information leading to HFD was obtained from the score calculated based on the GSEA and the usefulness of the transcriptome-driven evaluation using AOP was demonstrated.
Toxicity testing is critical for new drug and chemical development process. A clinical study, experimental animal models, and in vitro study are performed to evaluate the safety of a new drug. The limitations of these methods include extensive time for toxicity testing, an ethical problem, and high costs of experimentation. Therefore computational methods are considered useful for estimating chemical toxicity. In silico toxicity prediction is one of the toxicity assessments that uses computational methods to predict and stimulate the toxicity of chemicals. In silico study aims to contribute to effective development of new drug and chemical design. In this study, quantitative structure-activity relationship (QSAR) models will be used to predict toxicities based on chemical structural parameters. Because toxicities are complicated physiological phenomena, a similar toxicity expression might cause a different pathway. Also, since many drugs with unknown mechanisms of actions are available, the application of artificial intelligence (AI)—which uses sophisticated algorithms— is increasingly used to predict toxicities. Recently, the QSAR model was applied to determine complex relations between chemical structures and toxicities. However, accuracy of QSAR for toxicity prediction remains an important issue. International competitions funded by public institutions can address this issue. Two important toxicity challenges were organized in the past decade; this article presents issues of toxicity based on these challenges.
The thymus is a vital organ for functional immune systems, and is the site of T cell development, which plays a central role in cellular immune defenses. Unlike other major organs, the thymus is highly dynamic in size and structure. It shrinks immediately upon bacterial infection, aging, pregnancy, mental stress, nutritional deficiency, and more. The reduction in size and function of the thymus during such biological events is called thymic involution or thymic atrophy; thymic involution is a particularly important issue because dysfunctional T cell immunity increases the risks of tumorigenesis and infectious diseases. However, the molecular mechanisms underlying thymic involution remain obscure. Our recent study indicated that blood vessels are remodeled during thymic involution that occurs upon aging, estradiol-treatment, or nutritional deficiency. We also found that prostanoid synthesis is induced during thymic involution. Treatment with non-steroidal anti-inflammatory drugs (NSAIDs), aspirin or etodolac, at least partially inhibited thymic involution-induced remodeling of the blood vessels, suggesting that prostanoids are involved in blood vessel remodeling. Our results revealed the potential role of blood vessel remodeling during thymic involution, which can lead to biological stress-induced immunosenescence.
Repair of injured tissues requires angiogenesis, the growth of new blood vessels from pre-existing ones. Cutaneous wound healing is a complex and dynamic process by which skin tissue repairs itself after injury; however, how endothelial cells and pericytes form new blood vessels during cutaneous wound angiogenesis remains unclear. We recently developed a fluorescence-based live imaging system to analyze cutaneous wound angiogenesis in adult zebrafish. Employing this system, we found that endothelial cells and pericytes remain in a quiescent state in normal skin tissue, whereas cutaneous injury immediately activates both types of cells to induce angiogenesis. At 2 days post-injury (dpi), the injured vessels elongated, and some uninjured vessels became tortuous and began to sprout new branches. Then, vessel sprouting, elongation, bifurcation, and anastomosis progressively occurred to form the tortuous and disorganized vascular networks observed at 6 dpi. Thereafter, blood vessel tortuosity gradually decreased through the regression of excessive vessels, thereby leading to the formation of well-organized vessel networks at 42 dpi. Pericytes are thought to detach from the vessel wall to promote endothelial cell sprouting upon the induction of angiogenesis. However, not only endothelial cells but also pericytes proliferated to form pericyte-covered tortuous blood vessels in response to cutaneous injury, revealing an unexpected role of pericytes in cutaneous wound angiogenesis. Therefore, this live-imaging system for adult zebrafish is anticipated to make a valuable contribution to research advancements in understanding the angiogenesis that occurs during tissue repair.
Blood vessels supply oxygen and nutrients to all the cells in a living body, and provide essential transport routes for collecting waste products. For these functions, blood vessel networks should be appropriately formed in each tissue. Therefore, blood vessels are one of the earliest organs formed during the developmental process. Development of the blood vessel system promotes tissue differentiation and organ morphogenesis, allowing each organ to maintain its unique functions under changing metabolic conditions. Blood vessels have a relatively simple structure, consisting of endothelial cells covering the inner layer, and pericytes or smooth muscle cells surrounding the outside. The structure of the vascular network is extremely diverse, with blood vessels uniquely organized depending on the tissues they serve, to create tissue-specific microenvironments. How are such tissue-specific vascular environments generated? Over the years, anatomical findings have accumulated to confirm this vascular diversity. However, the molecular basis for this diversity has remained unclear. In the present article, we review the mechanisms of coordinated developmental control of the vascular and neural systems in the cerebral cortex from the viewpoint of the accurate expression control of vascular endothelial growth factor (VEGF) signaling, and describe future perspectives.
Interactions between carbohydrate-containing glycoproteins, proteoglycans, and glycolipids on the cell surface are important biological stages for the processes of bacterial or viral infection and tumor metastasis. Moreover, supramolecular interaction by macromolecules with two-fold (C2) or three-fold (C3) geometry is one of the common interactions in many important biological responses. To develop new multivalent symmetrical bioactive compounds or leads, we designed and synthesized several new molecules with these geometries and evaluated their bioactivities in an attempt to find new types of bioactive leads that may interfere with the sugar recognition process. We evaluated bioactivities including antibacterial, antiviral, and anticancer activities of targeted molecules in vitro using biological assay systems. Among the synthesized target derivatives examined, some bivalent symmetrical derivatives showed high levels of bioactivities. In this review, the author describes the results of synthesis of oligovalent symmetrical target compounds and some interesting guiding results of evaluation of their biological activities and structure-activity relationships.
I have been exploring methods for education and research on drug information for 43 years. There are various approaches to drug informatics research, which include collecting, evaluating, and analyzing information to solve drug related problems, sometimes producing new information from experiments and clinical research. All are based on information science. Drug informatics is information science from the viewpoint of pharmaceuticals. In addition to basic pharmacology, knowledge and skills such as epidemiology, data science, computer science, mathematical statistics, and communication studies are indispensable for the development of drug informatics.
When a hydrophobic group is introduced into a water-soluble polymer, self-assembly with the hydrophobic group as nucleus occurs in water. In the 1990s, many researchers focused on this phenomenon and various self-aggregates were prepared. Among them, a block copolymer consisting of a hydrophilic chain and a hydrophobic chain is associated in water, producing polymer micelles with the hydrophilic chain oriented in the outer shell and the hydrophobic chain as core. Meanwhile, many studies were conducted to create polymer self-associates by introducing hydrophobic groups into water-soluble polymers. In this review, the author describes hydrophobized polymers with polysaccharides and synthetic polymers that are frequently used as pharmaceutical raw materials. In addition are outlined the usefulness of hydrophobized polymers as carriers with the function of encapsulating and solubilizing poorly water-soluble drugs, along with the results of our research.
Daptomycin (DAP) has a completely different mechanism of action compared to conventional methicillin-resistant Staphylococcus aureus (MRSA) drugs and is widely used clinically as the first-line drug for the treatment of skin soft tissue infection and sepsis caused by MRSA infection. However, the most serious side effects of DAP include renal dysfunction and rhabdomyolysis. Knowledge of the time sequence of localization of DAP in cells and tissues of animals may help in developing a better understanding of the actual overall pharmacokinetics of DAP. We prepared DAP-specific antibodies by immunizing mice with DAP-GMBS-BSA conjugate. The Anti-DAP antibody was specific for DAP, which enabled us to develop an immunocytochemical method for detecting the uptake of DAP in the rat kidneys. One hour after a single intravenous (i.v.) injection of DAP at 12 mg/kg, immunohistochemical observation showed a strong ring-like positive reaction in the cytoplasm immediately below the microvilli of proximal tubule epithelial cells. The distal tubules and collecting ducts contained DAP-positive and negative cells in the cross section of one tubule. Twenty-four hours after DAP administration, several strong positive reactions of different sizes were observed in the cytoplasm of epithelial cells at the proximal tubule. No staining was detected after 7 days. This study will be a useful tool for analyzing the pharmacokinetics of DAP.
Elneopa NF No. 1 and No. 2 infusions are complete parenteral nutrition solutions packaged as four-chambered bags. They have been used for home parenteral nutrition, with insulin injected into the bags for patients whose blood glucose becomes elevated. In this study, the stability of insulin in No. 1 and No. 2 bags was investigated. The quantity of insulin in Elneopa NF No. 2 was significantly lower than that in Elneopa NF No. 1. When insulin was injected into the upper chamber of either product, decreases in insulin levels were not observed. In contrast, the levels of insulin injected into the lower chamber of both products significantly decreased, with a larger difference in Elneopa NF No. 2. As the amino acid content is different between No. 1 and No. 2, amino acids may be considered a potential cause for the degradation of insulin in the bags. In addition, decreases in insulin levels were observed as the solutions passed through infusion sets just after flushing began, with both Elneopa NF No. 1 and No. 2. In conclusion, the concentration of insulin injected into the Elneopa infusion bags decreases, especially in No. 2 bags, and insulin is absorbed by the infusion sets.
The prevalence of home parenteral nutrition (HPN)
continues to increase. Elneopa NF No. 1
and No. 2 infusions have been used for HPN, with insulin injected into the bags
for patients with hyperglycemia. In this study, the authors studied the stability
of insulin in the bags. It was revealed that the concentration of insulin
injected into the bags decreases, especially in No. 2 bags. In addition, decreases
in insulin levels were observed as the solutions passed through infusion sets.
Because patients and their families are at a high risk of contracting infectious diseases in hospital as well as pharmacy, a pharmacy containing the waiting rooms separately for infectious diseases and non-infectious diseases is expected to lead them to visit with confidence and receive appropriate drug administration guidance without the risk of infection. In this study, we examined the potential usefulness of having separate waiting rooms by conducting a questionnaire survey on the structure of the pharmacy waiting room and investigating the visiting situation for influenza-infected pediatric patients from a record of the medicines they received. As a result of the questionnaire tabulated from guardians of 385 pediatric patients who first visited a pharmacy with separate waiting rooms, 70% of the pediatric patients concluded that having separate waiting rooms would be satisfactory. In addition, the possible risk of horizontal transmission of influenza was supposed to be reduced in the pharmacy with separate waiting room in comparison with the pharmacies without among 211 pediatric patients who could not identify the influenza source within their daily living areas, such as home and school. Based on these findings, we anticipate the growing availability of the pharmacies having separation type waiting rooms.
Few studies have examined the relationship between the use of antidepressants and the onset of hyperglycemia and diabetes mellitus in Japan. We herein explored the possibility of this relationship using the Japanese Adverse Drug Event Report database (JADER). The present study included 20 individual antidepressants, consisting of 6 subclasses, which have been approved for use in Japan. We used Standardized MedDRA Queries 20000041 to extract patients who developed hyperglycemia/new onset diabetes mellitus (NODM) in JADER between April 2004 and September 2016. We calculated reporting odds ratios (RORs) with 95% confidence intervals (CI). We also calculated odds ratios defined as the ratio of odds of hyperglycemia/NODM to all other adverse drug events (ADEs) by the age cut-off group or sex in the cases of antidepressants. The lower limit of 95%CI of RORs for 13 antidepressants (imipramine, clomipramine, nortriptyline, amitriptyline, amoxapine, maprotiline, mianserin, sertraline, paroxetine, escitalopram, duloxetine, mirtazapine, and trazodone), which included all subclasses, exceeded 1. Younger age group was associated with hyperglycemia/NODM for 5 antidepressants (imipramine, amitriptyline, maprotiline, duloxetine, and trazodone), and female was associated with the ADEs for trazodone, although these results should be interpreted cautiously. Healthcare personnel need to be aware that the use of antidepressants may lead to hyperglycemia/NODM.