Skin inflammation is one of several allergic symptoms that are regulated by several mediator molecules. One of these molecules, calcitonin gene-related peptide (CGRP) affects several immune cells including T cells, B cells, dendiritic cells and mast cells. CGRP binds to CGRP receptors composed of receptor activity-modifying protein 1 (RAMP1) and calcitonin receptor-like receptor (CLR) to modulate various functions such as pain transmission and vasodilation. Studies showing that CGRP physiologically regulates skin inflammation using a CGRP antagonist, capsaicin-induced depletion model, RAMP1-deficient mice and mouse contact hypersensitivity (CHS) model have been reported. Interestingly, while CGRP has inhibitory effects on Th1-mediated CHS, it was demonstrated that CGRP enhances Th2-mediated CHS response. Moreover, these skin inflammations were affected by elevated CGRP concentrations through an abnormal condition of the nervous system induced by exposure to psychological stress or neonatal chemical stimulation. In this review, we present the importance of CGRP in the regulation of skin inflammation under the several nervous conditions and provide a new insight into understanding various types of skin inflammation and skin diseases.
Contact dermatitis is an inflammatory skin disease caused by toxic factors that activate the skin innate immunity (irritant contact dermatitis) or by a T cell-mediated hypersensitivity reaction (allergic contact dermatitis). These inflammatory skin diseases are sometimes still not easy to control. Therefore, the development of new effective drugs with fewer side effects is anticipated. In the skin under pathophysiological conditions, multiple prostaglandins are produced and their receptors are expressed in time- and/or cell-dependent manners. However, the precise role of prostaglandins and their receptors in contact dermatitis has not been fully understood. Recently, studies using mice with a disruption of each prostaglandin receptor gene, as well as receptor-selective compounds revealed that prostaglandin receptors have manifold functions, sometimes resulting in opposite outcomes. Here, we review new advances in the roles of prostaglandin receptors in contact hypersensitivity as a cutaneous immune response model, and also discuss the clinical potentials of receptor-selective drugs.
The primary function of surfactants is to remove dirt, exfoliated corneum cells, and microorganisms from the skin. However, the use of toiletries such as soaps and shampoos containing surfactants may cause adverse effects such as cutaneous irritation, dryness, and itching. Recently, skin pathologies, including dry skin, rough skin, and sensitive skin, have increased because of changes in living conditions and lifestyle. Although many people with skin pathologies complain of itching during and/or after skin washing using detergents, the mechanisms of detergent-induced itch are yet to be elucidated. Therefore, in this study, we investigated the mechanisms underlying surfactant-induced itching. We found that topical application of an anionic surfactant sodium laurate at an alkaline pH, but not N-lauroylsarcosine sodium salt at neutral pH, to mouse skin induced scratching, an itch-related response. Additionally, we found that the sodium laurate-induced scratching was inhibited by H1 histamine receptor antagonist, but not mast cell deficiency. Sodium laurate application increased histamine content and the level of the active form (53 kDa) of L-histidine decarboxylase (HDC) in the mouse epidermis, but not the dermis. Furthermore, addition of sodium laurate to a human epidermal cell culture increased histamine release and HDC levels, without affecting cell viability. These results suggest that surfactants with alkaline properties are pruritogenic and that the pruritus is induced by the histamine released from epidermal keratinocytes. The increase in histamine release may be attributable to the activation of HDC in epidermal keratinocytes.
A diverse array of nanomaterials (NMs), such as amorphous nanosilica (nSP), carbon nanotubes and titanium dioxide, has become widespread in use due to the development of nanotechnology. NMs are already being applied in universal fields because they have unique physicochemical properties. On the other hands, the safety of NMs has not been well assessed, because NMs have been considered as safe as common larger sized materials which are known not to be absorbed by the body. Because NMs have the potential to improve the quality of human life, it is essential to ensure the safety of NMs and provide information for designing safer NMs. In this regard, we studied the biological distribution and hazard identification of nSP following dermal administration, because nSP is used NMs in the cosmetics field. In the future, our study would help to set the no observed adverse effect level (NOAEL) and acceptable daily intake (ADI), and be useful information for the safety/hazard assessment and evaluation.
Skin has been paid attention as a site of application of prescription drugs, over-the-counter drugs (non-prescription drugs) and cosmetics. Skin permeation and skin concentration of the compounds should be considered after topical administration, as well as their blood concentration to evaluate efficacy and safety. Since the evaluation of the amount of drugs permeated through skin is important for topically applied drugs, studies on the skin permeation has been greatly advanced. In addition, many reports proved that skin permeabilities of drugs could be predicted from physicochemical parameters of drugs. On the other hand, few reports have been found on the prediction of skin concentration of drugs. Furthermore, many experimented problems are left to determine the skin concentration of drugs: severe consume of human or animal skins, difficult removal of applied drugs from the skin surface, low drug extraction ratio from skin and low sensitivity to determine skin concentration of drugs, and requirement of long time measurement. Thus, fast and accurate measurement of skin concentration of applied drugs are urgently required. This report describes the relationship between skin permeation and skin concentration, and the prediction of skin concentration of drugs using skin permeation parameters of drugs.
Olfactory cells receive numerous odorants including toxic substances. To avoid complete loss of the olfactory function by toxic odorants, continuous neurogenesis of olfactory cells occurs even at adulthood. Newly generated olfactory neurons extend their axons to the olfactory bulb. Various molecules including polypeptides, proteins, polynucleotides, virus, and cells administrated intranasally have been reported to move from the olfactory epithelium to the brain tissue via the olfactory epithelium-olfactory bulb pathway. I discuss the pathway of substances intranasally administrated to the brain from the view point of characteristics of the olfactory epithelium.
Nasal absorption of insulin was discussed to develop a delivery system that targets the systemic circulation or central nervous system. Formation of insulin dimer and hexamer affects not only the diffusivity but also the membrane permeability of insulin via aqueous channels. The Renkin function was used to evaluate penetration pathways of hydrophilic compounds containing insulin through aqueous channels, and pore size and occupancy of the pathways were obtained as the membrane parameters on the basis of the function. Cationic polymers applied on the mucosal membranes as penetration enhancers increased the number of pathways for the hydrophilic compounds in the tight junctions, which suggested that these compounds could be sufficient as additives for the nasal delivery of insulin. However, excess interaction of the cationic enhancers with anionic insulin suppressed insulin permeation, and protection of insulin against degradation in the permeation process was required to improve the nasal absorption. PEGylation of insulin could be a possible way to improve the nasal delivery of insulin. In addition, combination of PEGylated insulin and modified cyclodextrin, which form pseudorotaxanes, can be applicable for further modification of pharmacokinetic and pharmacodynamic properties of insulin. Such well-designed complex systems may be required for specific delivery of insulin to the central nervous system.
Nasal administration of macromolecular drugs (peptides, nanoparticles) has a possibility to enable a drug delivery system beyond the blood brain barrier via olfactory nerve transport. Basic research on nasal drug delivery to the brain has been well studied. However, evaluation of the olfactory nerve transport function in patients with olfactory disorders has yet to be done, although such an evaluation is important in selecting candidates for clinical trials. Current olfactory function tests are useful for the analysis of olfactory thresholds in olfaction-impaired patients. However, the usefulness of using the increase in olfactory thresholds in patients as an index for evaluating olfactory nerve damage has not been confirmed because of the difficulty in directly evaluating the viability of the peripheral olfactory nerves. Nasally administered thallium-201 migrates to the olfactory bulb, as has been shown in healthy volunteers. Furthermore, transection of olfactory nerve fibers in mice significantly decreases migration of nasally administered thallium-201 to the olfactory bulb. The migration of thallium-201 to the olfactory bulb is reduced in patients with impaired olfaction due to head trauma, upper respiratory tract infections, and chronic rhinosinusitis, relative to the values in healthy volunteers. Nasally administrating thallium-201 followed by single photon emission computed tomography, X-ray computed tomography and magnetic resonance imaging might be useful in choosing candidates for clinical trials of nasal drug delivery methods to the brain.
Janus kinase 2 (JAK2) is an essential non-receptor type tyrosine kinase for various cytokine signals. In 2005, a somatic JAK2 mutation (V617F) was found in the majority of myeloproliferative neoplasm (MPN) patients. It has been shown that the V617F mutation caused the constitutive activation of JAK2, exhibiting the cytokine-independent survival and proliferation of Ba/F3 cells. In addition, tumorigenesis was induced after a transplantation of Ba/F3 cells expressing JAK2 V617F mutant in nude mice, suggesting that JAK2 V617F mutant behaves as a potent oncogene product. We found that JAK2 V617F mutant causes aberrant activation of a transcription factor c-Myc, which is critical for the JAK2 V617F mutant-caused oncogenic activities. In the screening of genes which expression was induced by JAK2 V617F mutant, we detected the significant induction of target genes of c-Myc such as Aurora kinase A (Aurka) and ornithine decarboxylase (ODC). Interestingly, JAK2 V617F mutant enhanced resistance to cisplatin (CDDP)-induced DNA damage and ectopic expression of Aurka in Ba/F3 cells exhibited similar resistance to CDDP. Conversely, knockdown and inhibition of Aurka in cells expressing JAK2 V617F mutant abolished the resistance to CDDP, suggesting that Aurka is most likely critical for resistance to DNA damage in cells transformed by JAK2 V617F mutant. In addition, we found that ODC inhibitor, DL-α-difluoromethylornithine (DFMO) prevented the proliferation of the JAK2 V617F mutant-induced transformed cells. Taking these observations together, c-Myc plays an essential role in JAK2 V617F mutant-induced hematopoietic disorder and would be a good target for the treatment of MPN.
In the post-genome era, the analysis of disease-related genes has rapidly advanced, and the medical application of the information obtained from gene analysis is being put into practice. In particular, the development of a novel system to transfect the gene of interest selectively and efficiently into targeted cells is essential for the gene therapy of refractory diseases, in vivo functional analysis of genes, and establishment of animal models for diseases. However, a suitable carrier for selective gene delivery to targeted cells remains to be developed. The sonoporation method using microbubbles and ultrasound (US) exposure is one of the most promising approaches for effective gene transfection. However, it is difficult to transfect the therapeutic gene into the targeted organs/cells selectively by the conventional sonoporation method. Recently, our group has developed mannose-modified and US-responsive carriers/nucleic acid complexes (Man-PEG2000 bubble lipoplexes), and succeeded in obtaining the enhanced and selective gene expression in mannose receptor-expressing cells by combination with US exposure. In this review, I described our gene transfection methods using Man-PEG2000 bubble lipoplexes and external US exposure. Additionally, I also reviewed the enhancing mechanism of gene expression focusing on the intracellular transporting processes, in vivo distribution, and the activation of transcriptional factors. I believe that these findings help in the development of an effective gene transfection system using US-exposing system.
Platinum agents are widely used in cancer chemotherapy. Cisplatin, carboplatin, oxaliplatin and nedaplatin have a common chemical structure consisting of platinum, carrier groups and leaving groups, and undergo the similar mechanism of cytotoxicity. Only cisplatin induces nephrotoxicity, although the molecular mechanism involved is unclear. Organic cation transporter (OCT)/SLC22A, and multidrug and toxin extrusion (MATE)/SLC47A play a role in renal handling of cationic drug in the kidney. We focused on a role of transporters in nephrotoxicity of platinum agents. OCT2 mediates the transport of cisplatin and is the determinant of cisplatin-induced nephrotoxicity. In addition, MATE1 protects cisplatin-induced nephrotoxicity. Oxaliplatin, which was a superior substrate of the luminal efflux transporter, MATE2-K as well as OCT2, did not show nephrotoxicity. Moreover, carboplatin and nedaplatin were not transported by these transporters. Substrate specificity could regulate the features of platinum agents. Recent findings indicate that organic cation transporters are key to the nephrotoxicity of platinum agents.
The synthesis of β-lactams with contiguous tetra- and trisubstituted carbon centers has been accomplished via the 4-exo-trig intramolecular conjugate addition of C-N axially chiral enolates generated from α-amino acid derivatives. Use of a metal carbonate in a protic solvent (i.e., Cs2CO3 in EtOH) was found to be critical for the success of the reaction. Under optimized reaction conditions, axially chiral enolates were generated in very low concentration, thereby favoring intramolecular conjugate addition while minimizing intermolecular side reactions. The highly strained β-lactam enolates formed through this reversible intramolecular conjugate addition were rapidly protonated by EtOH in the reaction media to afford β-lactams in up to 97% ee.
Density functional theory (DFT) calculations are established as a useful research tool to investigate the structures and reactivity of biological systems; however, their high computational costs still restrict their applicability to systems of several tens up to a few hundred atoms. Recently, a combined quantum mechanical/molecular mechanical (QM/MM) approach has become an important method to study enzymatic reactions. In the past several years, we have investigated B12-dependent diol dehydratase using QM/MM calculations. The enzyme catalyzes chemically difficult reactions by utilizing the high reactivity of free radicals. In this paper, we explain our QM/MM calculations for the structure and reactivity of diol dehydratase and report key findings with respect to the catalytic roles of the active-site amino acid residues, computational mutational analysis of the active-site amino acid residues, assignment of the central metal ion, and function of the central metal ion. Our QM/MM calculations can correctly describe the structures and activation barriers of intermediate and transition states in the protein environment. Moreover, predicted relative activities of mutants are consistent with experimentally observed reactivity. These results will encourage the application of QM/MM research to the mechanistic study of enzymatic reactions, functional analysis of active-site residues, and rational design of enzymes with new catalytic functions.
The dissolution test is a core performance test in pharmaceutical development and quality control of solid drug products. The conventional HPLC dissolution method (batch-sampling method) involves many steps including the filtration, collection and replenishment of sample solutions. We previously reported a dissolution test that involved microdialysis methods (microdialysis-HPLC method) and allowed many steps to be omitted. However, the recovery rate of theophylline by the microdialysis-HPLC method was lower, and the decrease in the flow rate through the dialysis probe caused variation between each tablet. In this study, we have attempted to improve the dissolution test by using a precise micro-controlled roller pump and microfiltering probe (microfiltering-HPLC method). Sustained release preparations of Theodur® (100 mg) were used, and the test solutions used were water, buffer at pH 1.2 and pH 6.8, and pH 6.8-buffer containing 0.1-1% polysorbate 80 or sodium lauryl sulfate. In all test solutions, the microfiltering-HPLC method was able to accomplish continuous sampling of sample solutions, and the recovery rate of theophylline was over 90%. The dissolution behavior by the microfiltering-HPLC method tends to reflect the pharmaceutical design in comparison with the batch-sampling method, and the standard deviations by the microfiltering-HPLC are lower than with the batch-sampling method. In addition, the microfiltering-HPLC method allows many steps to be omitted, such as the filtration, collection and replenishment of sample solutions. These findings provide significant information that can be used in the pharmaceutical development and quality assessment of solid drug products.
The purpose of this study was to examine the relationship between the crystalline metastasis of lactose, which is a main component baby milk powder, and the hardness of baby milk powder compressed by humidification followed by drying. Because baby milk powder is manufactured using a spray dryer, lactose in compressed baby milk powder exists in an amorphous (solid dispersion) form. X-ray diffraction measurement showed that this amorphous lactose metastasized to β-form crystalline lactose, and thereafter metastasized to the α-form during the humidification-drying process. As a result of this crystalline metastasis, the hardness of the compressed baby milk powder increased, and then decreased. Furthermore, scanning electron microscopy (SEM) showed bridging structures between the particles increased and then decreased during the humidification-drying process. This showed that bridging structures between the particles produced by crystalline metastasis of lactose as a result of the humidification-drying process, which leads to an increase in the hardness of the compressed baby milk powder. These results show that the necessary degree of hardness of the porous compressed baby milk powder (necessary for packaging and transportation) resulted from the humidification-drying process.