Mast cells are hematopoietic-lineage cells that participate in immunoglobulin E (IgE)-associated immune responses, including allergic reactions and parasite resistance. Recent studies have shown that zinc (Zn) ion can behave as an intracellular signaling molecule and that Zn is involved in mast cell activation. We demonstrated that mast cells stimulated through the high-affinity IgE receptor (FcεRI) rapidly release intracellular Zn from the endoplasmic reticulum (ER), and we named this phenomenon the “Zn wave”. Furthermore, we found that the L-type calcium channel (LTCC) is the gatekeeper for the Zn wave. LTCC antagonists inhibited the Zn wave, and an agonist was sufficient to induce it. Notably, LTCC was mainly localized to the ER rather than to the plasma membrane in mast cells, and the Zn wave was impaired by LTCC knockdown. We also found that the LTCC-mediated Zn wave positively controlled inflammatory cytokine gene induction by enhancing the DNA-binding activity of nuclear factor-kappa B (NF-κB). These findings indicated that the LTCC has a novel function as a gatekeeper for the Zn wave, which is involved in regulating NF-κB signaling. In this review, we describe our current understanding of Zn signaling, especially with regard to the Zn wave and the role of Zn signaling in mast cells.
Mast cells originate from hematopoietic stem cells and undergo terminal maturation in the extravascular tissues, in which they are ultimately resident. Mast maturation, phenotype, and function are dictated by the local microenvironment, which has a significant influence on the ability of mast cells to recognize and respond to stimuli. Activation of mast cells can lead to the release of three distinct classes of mediators, including preformed mediators stored in secretory granules, newly transcribed cytokines and chemokines, and de novo-synthesized bioactive lipid mediators. It is currently recognized that bioactive lipids such as arachidonic acid metabolites (prostaglandins and leukotrienes) released from mast cells modulate innate and adaptive immune responses both directly and indirectly through communication with other microenvironmental immune cells or stroma cells. Moreover, mast cells express a variety of lipid receptors and, if activated by bioactive lipids such as arachidonic acid, ω3 fatty acids, lysophospholipids, and their metabolites, can alter the release and production of other mediators including histamine, cytokines, and chemokines, and thereby alter homeostatic or pathophysiological responses. This review focuses on newly identified functional aspects of bioactive lipids with regard to their immune regulation and functional outcomes in both homeostasis and allergic disease.
Mast cells are effector cells in immunoglobulin E (IgE)-mediated immediate hypersensitivity and allergic diseases such as asthma and food allergy. Mast cells are activated by the aggregation of the IgE-bound high-affinity IgE receptor FcεRI with multivalent antigen. Activated mast cells secrete proinflammatory mediators such as histamine, serotonin, and proteases and produce cytokines and chemokines. However, it has been reported that mast cells are activated by crosslinking of FcεRI with monomeric IgE in the absence of antigen. We have recently demonstrated that histamine-releasing factor (HRF) is involved in IgE-mediated mast cell activation both in vitro and in vivo. HRF binds to a subset of IgE and IgG molecules [HRF-reactive antibodies (Abs)]. The Fab, but not Fc, portions of the IgE and IgG molecules are HRF-binding sites, and the N-terminal 19-residue (N19) and H3 portions of HRF are HRF-reactive Ab-binding sites. We observed that both N19 and H3 tagged with glutathione S transferase (GST) (GST-N19 and GST-H3) can inhibit the interaction between HRF and HRF-reactive Abs. Using acute- and late-phase passive cutaneous anaphylaxis mouse models, it was shown that HRF initiates mast cell activation through HRF-reactive, but not HRF-nonreactive, IgE in vivo. Antigen-induced passive cutaneous anaphylaxis was inhibited by pretreatment with GST-N19 and GST-H3. We demonstrated that pretreatment with GST-N19 before antigen challenge inhibited antigen-induced mast cell-dependent airway inflammation. In addition, GST-N19 partially inhibited Aspergillus fumigatus extract-induced IgE-dependent airway inflammation. However, GST-N19 did not inhibit T cell-dependent airway inflammation. These results suggest that mast cells are target cells for HRF to initiate IgE- and mast cell-dependent airway inflammation.
Hydrophobic interaction chromatography (HIC) and MS are leading techniques for the characterization of the critical quality attributes (CQA) of antibody-drug conjugates (ADCs). This includes the average drug-to-antibody ratio (DAR) and drug loading distribution. A workflow that effectively utilizes the synergy between chromatography and detection technologies has been developed and was assessed using cysteine-conjugated ADCs. The DAR of low, moderate and high drug-loaded ADC samples were calculated from the chromatographic peak areas using LC(HIC)/UV or the deconvoluted mass spectra using native LC(SEC)/MS. The results of DAR by both technologies produced comparable results. In addition, the 2D-LC/MS system has been evaluated in combination with HIC and reversed-phase chromatography for structural identification. Individual peaks from the 1st dimension of the HIC separation were isolated online and re-directed to the 2nd dimension reversed-phase column. ADC was detected as the sub-units by MS and the conjugation site was identified via a middle down approach.
Recent advances in antibody-drug conjugate (ADC) technology have shown considerable promise in targeted cancer therapy. The ADC strategy should be confined to highly toxic anticancer agents and not to ordinary anti-cancer agents (ACAs) because the affinity of monoclonal antibodies (mAbs) diminishes if more than three ACA molecules are conjugated. According to this principle, higher amounts of ADC should be administered so that each of the ACAs is conjugated to the mAbs. Therefore for an ordinary ACA, nanoparticles should be the preferred drug delivery system (DDS). A large body of clinical evidence indicates that abnormal coagulation occurs in a variety of cancer patients, especially in invasive cancers. Tissue factor (TF), expressed on the surface of various cancer cells and tumor vascular endothelial cells, is the trigger protein of extrinsic coagulation resulting in insoluble fibrin formation. We have developed mAbs against TF and human fibrin that reacted only with human fibrin and not with human fibrinogen. We now propose cancer stromal targeting (CAST) therapy and diagnosis, using a cytotoxic agent or radioisotope conjugated to a monoclonal Ab directed at a specific inert constituent of the tumor stroma, as a new modality especially for invasive cancer.
Antibody-drug conjugates (ADCs) comprise an antibody, a linker, and a drug or payload. The selection of a tumor-specific antibody and development of a linker having an efficient controlled drug release (CDR) are critical steps in developing a fully functional and effective ADC. In our research strategy, molecular imaging technologies have been employed to evaluate the efficiency of antibody delivery and CDR of the linker. In preclinical setting, antibody delivery into the tumor area or antibody penetration through the tumor stroma in malignant lymphoma or pancreatic tumor was evaluated by in vivo fluorescence imaging technique. Positron emission tomography (PET) imaging studies were conducted using 89Zr-labeled antibody to evaluate tumor targeting in a spontaneous carcinogenesis model. The model had dense stroma and was pathophysiologically very similar to human cancer. The drug imaging system, using microscopic mass spectroscopy (MMS) with enhanced resolution and sensitivity, was used for the evaluation of CDR. Paclitaxel (PTX)-incorporated micelle, a high-molecular-weight (HMW) carrier with CDR, showing similar properties as those of ADC, was analyzed. In contrast to free PTX, micelle selectively increased drug accumulation into the tumor and reduced toxicity in normal tissues by the enhanced permeability and retention (EPR) effect. Our drug imaging system has been used recently to evaluate the CDR of the ADC-linker. We present our work on the development of ADC using a molecular imaging technique.
Antibody-drug conjugates (ADCs) selectively deliver large amounts of antitumor drugs to tumor tissue and show significant antitumor effects with a wide therapeutic window. We developed a new linker-drug technology platform with an exatecan derivative, which is a highly potent topoisomerase I inhibitor. The major advantages of the technology are: 1) high and homogeneous drug-to-antibody ratio (DAR) availability; 2) potent antitumor activity in conjunction with bystander killing; 3) few safety concerns because of the stable linker limiting release of free drug; and 4) a wide application to therapeutic antibodies. Using this linker-drug technology, we generated an anti-HER2 ADC, namely DS-8201a. DS-8201a, in which almost all eight cysteine residues of the antibody are bound to drug, was effective against trastuzumab DM1 (T-DM1)-insensitive patient-derived xenograft (PDX) models with high HER2 expression and also demonstrated antitumor efficacy against several breast cancer PDX models with low HER2 expression. DS-8201a was well tolerated in rats and monkeys following repeated administration. These results suggest that DS-8201a may be efficacious in a broader population of HER2-positive cancer patients and also confirm the importance of this new class of novel topoisomerase I inhibitor-based ADC technology.
Development of novel medicines is an important responsibility of researchers in the field of pharmaceutical sciences. However, the discovery of new therapeutically effective without side effects is not an easy job. I think the limiting step of drug discovery is the process of evaluating the therapeutic effects of candidate drugs. To overcome this problem, I would like to propose a novel approach, “drug discovery with silkworms”.
A growing body of evidence indicates that extracellular ATP released or leaked from nonexcitable cells as well as neurons plays important roles in the regulation of neuronal and glial functions in the entire body through ATP receptors. ATP receptors (ionotropic P2X and metabotropic P2Y receptors) are the most abundant receptor families in living organisms. In the central nervous system, these receptors participate in the synaptic transmission and intercellular communications between neurons and glia. The glia cells are classified into three types: astrocytes; oligodendrocytes; and microglia. There are many reports that spinal microglia express ATP receptors (P2X4, P2X7, P2Y6, and P2Y12 receptors) that have very important roles. We reported that several molecules of microglia are activated after peripheral nerve injury in a neuropathic pain model. In particular, P2X4 receptors (P2X4Rs) expressed in microglia play a critical role in evoking neuropathic pain. P2X4Rs are upregulated in spinal microglia after nerve injury by several factors such as the CC chemokine receptor CCR2, fibronectin in the spinal cord, interferon regulatory factor (IRF) 8, and IRF5 expressed in microglia. The inhibition of P2X4R action suppresses the functions of microglia and neuropathic pain. These results indicate that overexpressing P2X4Rs on microglia are a central player in evoking neuropathic pain.
The super-aging society in Japan is currently experiencing growing demand for treatments that improve health and longevity. To develop new high-functional foods and search for pharmaceutical candidates among foods and natural products, it is necessary to promote organic collaboration among researchers in pharmacy, medicine, nutrition, and other fields to encourage joint utilization of their technologies. Recently, attempts have been made to use numerous foods and natural products to prevent or treat diseases based on scientific evidence. We have been endeavoring to develop preventive medicines from foods and natural ingredients by engaging in relevant activities such as screening these substances to determine the structures of their effective ingredients, verifying pharmacological activities, and conducting clinical trials. In this study, the effectiveness of Goishi tea (postfermented tea) and Flos Lonicerae (Japanese honeysuckle) for metabolic syndrome and hepatic disorders, respectively, was explored. Multicomponent foods and natural ingredients have diverse effects produced by the actions of individual components as well as the interactions among different components. Additionally, when using natural ingredients and similar materials, it is necessary to consider the different extraction efficiencies of various methods and their absorption, deposition, metabolism, and excretion after consumption. The influence of intestinal bacteria and other factors is also critical. In our study, the administration of Goishi tea and Flos Lonicerae in animal models of disease demonstrated high functionality. Based on these findings, we plan to conduct further investigations, including clinical studies in human participants, focusing on the potential usefulness of Goishi tea and Flos Lonicerae as functional foods.
Magnesium oxide (MgO) tablets are widely used as laxatives in patients with constipation. Recently, the “Revision of Precautions on the Use of Magnesium Oxide” has been issued by the Japanese Pharmaceuticals and Medical Devices Agency, warning against the risk of hypermagnesemia with the use of MgO. However, the majority of physicians continue to administer MgO for constipation without adequately considering its safe use. In the present study, we performed two analyses using an identical lot of MgO tablets and evaluated the risk of hypermagnesemia. Approximately 90% of the MgO tablets dissolved within 120 min in dissolution testing; it was believed to form an absorbable state for magnesium. With orally administered MgO, 15% is absorbed in the body and 85% is excreted via the feces without being detected in pharmacokinetic analysis. Magnesium absorbed into the plasma demonstrated peak concentration 3 h after administration and was excreted via the urine within 48 h.
In this study, we established a methodology to calculate the rate of overlooking a dispensing error (inspecting error rate) as a new index for the purpose of determining dispensing error and malpractice rates. Using data obtained from analyses of these error rates at our and two other hospitals, an inspecting error rate was calculated for each institution. Our results showed that inspecting errors occurred at a frequency 3-5 times greater as compared to dispensing errors at each of the examined hospitals. We concluded that construction of a higher quality safety management system would be enabled by incorporation of an inspecting error rate as a new index to evaluate medical safety in regard to dispensing of medicines and managing inspection accuracy.
Similarities among non-prescription pharmaceutical vitamin products generally available in community pharmacies were examined based on their vitamin components, and a chart was constructed to differentiate products to assist in appropriate product choice. In the analysis of the similarities, two hundred and seventy-six data entries on vitamin products were extracted from the database on the package inserts of the pharmaceutical products provided by the Pharmaceuticals and Medical Devices Agency, and they were reviewed for the amounts of vitamins they contained, in which the B vitamins, or vitamin B1, B2, B6, B12, and niacin, were considered as well as vitamins C and E. Pantothenic acid and L-Cysteine that are frequently used in combination with those vitamins are also taken into consideration. The data entries were then processed by classical multi-dimensional scaling to evaluate the inter-product similarities. As a result, it was shown that the products categorized as pharmaceutical nutrients and tonics containing vitamins (NTcV) are similar to one another, reflecting the fact that they are less characteristic regarding their vitamin components. As for the products in other categories, they were generally found to be featured for their unique content of vitamin components, and thereby, each category includes products with a wide range of variation. It was also indicated that some products categorized as vitamin B1, B2, and C products are less distinguishable from those categorized as NTcV. These findings will assist pharmacists to decide on an appropriate product for a customer following consultation.
The Hakodate Watanabe Hospital has held pharmacist-led multidisciplinary psychiatric pharmacotherapy conferences since September 2013 in order to optimize pharmacotherapy. The effects of holding regular conferences on the correction of high-dose antipsychotic polypharmacy, prevention and reduction of adverse reactions to antipsychotics, and reduction of the drug costs were investigated in psychiatric inpatients prescribed 4 or more antipsychotics. The results revealed that the number of antipsychotics and number of all drugs were significantly reduced by 1, the chlorpromazine (CP)-equivalent dose was significantly reduced by approximately 350 mg, and the drug costs were significantly reduced by 176.5 yen/d. In regard to the effects on the laboratory test data, the blood glucose and hemoglobin A1c (HbA1c) levels were significantly reduced. In addition, 84.8% of the patients were assessed as “unchanged” using the Clinical Global Impression of Change (CGI-C), indicating the absence of any significant changes in the severity of the clinical psychiatric symptoms. The results confirm that psychiatric pharmacotherapy conferences are effective for promoting appropriate use of antipsychotics, reducing the incidence of metabolic adverse reactions, such as elevation of the blood glucose, and also reducing the drug costs. The above results suggest that psychiatric pharmacotherapy conferences encourage psychiatric medical teams to adjust prescriptions while sharing information, and are effective for optimizing pharmacotherapy.
Liver and hepatocyte hypertrophy can be induced by exposure to chemical compounds, but the mechanisms and toxicological characteristics of these phenomena have not yet been investigated extensively. In particular, it remains unclear whether the hepatocyte hypertrophy induced by chemical compounds should be judged as an adaptive response or an adverse effect. Thus, understanding of the toxicological characteristics of hepatocyte hypertrophy is of great importance to the safety evaluation of pesticides and other chemical compounds. To this end, we have constructed a database of potentially toxic pesticides. Using risk assessment reports of pesticides that are publicly available from the Food Safety Commission of Japan, we extracted all observations/findings that were based on 90-day subacute toxicity tests and 2-year chronic toxicity and carcinogenicity tests in rats. Analysis of the database revealed that hepatocyte hypertrophy was observed for 37-47% of the pesticides investigated (varying depending on sex and testing period), and that centrilobular hepatocyte hypertrophy was the most frequent among the various types of hepatocyte hypertrophy in both the 90-day and 2-year studies. The database constructed in this study enables us to investigate the relationships between hepatocyte hypertrophy and other toxicological observations/findings, and thus will be useful for characterizing hepatocyte hypertrophy.
Pharmacists applied deprescribing, which is a process for the rational use of drugs, for 13 at-home patients. The standard used for the rational use of drugs was the “Guidelines for Medical Treatment and Its Safety in the Elderly” (the Guidelines). The results of the deprescribing were discussed with physicians to determine prescriptions. After the prescription change, activities of daily living (ADL) and QOL were assessed using the Barthel Index and SF-36v2, respectively. Potentially inappropriate medications (PIMs) were detected in 10 of the 13 patients (76.9%). This detection rate is higher than previous PIM detection rates of 48.4% and 40.4% reported in prescriptions for home-care patients in Japan under the Beers and STOPP/START criteria. The Guidelines appeared useful as a decision support tool for deprescribing. The patients continuing the changed prescriptions showed no decrease in ADL or QOL after deprescribing, suggesting its rationality. The 10 measurement items of the Barthel Index were all suitable for evaluating the physical conditions of the patients. Meanwhile, SF-36v2 includes many items, but few indexes were directly applicable.
Foreign matter sensation and blurred vision following instillation of ophthalmic suspension are often observed, and remaining of solid particle on cornea is related these side effects. In addition, low dispersion stability in the ophthalmic suspension affects the therapeutic effect. In this study, we have attempted to enhance the dissolution rate and stability of commercially available pirenoxine ophthalmic suspension (CA-pirenoxine eye drops), anti-cataract eye drops, by changes in particle size. Methylcellulose, zirconia beads (0.1 mm) and Micro Smash were used to mill the pirenoxine (bead mill method), and the distribution of particle size was changed to approximately 60-900 nm (nanodispersions) from 70 nm-3 μm (CA-pirenoxine eye drops). The dissolution rate of pirenoxine increased by the bead mill, and the dissolution rate constant in pirenoxine nanodispersions was 2.1-fold than that in CA-pirenoxine eye drops. Moreover, the dispersion stability in nanodispersions also significant higher in comparison with the CA-pirenoxine eye drops. The dispersion ratio in CA-pirenoxine eye drops and pirenoxine nanodispersions at 2 d after suspension was 48%, 99%, respectively. In conclusion, we showed that the dissolution rate and dispersion stability of CA-pirenoxine eye drops were enhanced by the bead mill method. These findings provide significant information that can be used in the design of ophthalmic suspension.
In recent years, hospitals have routinely implemented antimicrobial stewardship (AS) programs, and it is important that these programs are effective. Consequently, we utilized a customized computer system to support infection management and implemented a pharmacist-driven AS program in our hospital. Using this computer system, a pharmacist monitored the daily usage of carbapenems and agents against anti-methicillin-resistant Staphylococcus aureus and generated a patient database. With the use of this computer system, we found that the patient database entry time significantly decreased from 24 to 12 min (p<0.01). Subsequently, we were also able to monitor tazobactam/piperacillin usage owing to the increased efficiency of our AS program. As a result, the average number of monitored patients significantly increased from 51 to 72 per month (p<0.01) and the number of proposed prescriptions increased from 189 to 238 per year. Additionally, the usage of carbapenems and tazobactam/piperacillin significantly decreased (p<0.01) after implementation of this computer support system. In summary, we recommend that pharmacists utilize computer systems to implement AS programs because they increase the efficiency of interventions and monitoring of patients and promote appropriate antibiotic use.