Scn1a and Cacna1a mutations mutually alter their original phenotypes in rats

This study aimed to examine the effects of Cacna1a mutation on the phenotype of Scn1a-associated epilepsy in rats. We used rats with an N1417H missense mutation in the Scn1a gene and others with an M251K mutation in the Cacna1a gene. Scn1a/Cacna1a double mutant rats were generated by mating both Scn1a and Cacna1a mutants. We investigated general health and the epileptic phenotype in all these genotypes. The onset threshold of hyperthermia-induced seizures was examined at 5 weeks and spontaneous seizures were monitored using video-EEG recordings from 6 to 12 weeks of age. Scn1a/Cacna1a double mutants showed significantly reduced threshold for hyperthermia-sensitive seizures onset compared with the Scn1a mutants and had absence seizures having 6–7 c/s spike-wave bursts with changes in the spike-wave pattern, whereas Cacna1a mutants had regular 6–7 c/s spike-wave bursts. In Scn1a/Cacna1a double mutants, 6–7 c/s spike-wave bursts were accompanied with eyelid myoclonia and continuously shifting generalized clonic seizures, which were not observed in either Scn1a or Cacna1a mutants. Although a curvature of the spine was observed in rats of all these genotypes, the degree of curvature was more pronounced in Scn1a/Cacna1a double mutants, followed by Cacna1a and Scn1a mutants. Our results indicate that Cacna1a and Scn1a mutations mutually alter their original phenotypes in rats. The phenotype of absence seizures with eyelid myoclonia, generalized clonic seizures, and of spine curvature in the Scn1a/Cacna1a double mutants were similar to that observed in patients with Dravet syndrome

Different Responses to 5-fluoraouracil in Mutagenicity and Gene Expression between Two Human Lymphoblastoid Cell Lines with or without TP53 Mutation

Human lymphoblastoid TK6 and WTK-1 cells are widely used to detect mutagens in vitro. TK6 cells have wild-type TP53 alleles, while WTK-1 cells have one allele of mutated TP53. Both cells were treated with 5-fluorouracil (5-FU), and gene mutation assay and micronucleus assay were performed to clarify the differential response related to the TP53 gene status. The effects of 5-FU on gene expression were assessed by microarray and quantitative RT-PCR analyses. In WTK-1 cells, 5-FU increased the frequency of cells with micronucleus and mutation. In TK6 cells, frequency of cells with micronucleus was increased but the mutation frequency was not. The cytotoxicity induced by 5-FU was more prominent in TK6 cells than in WTK-1 cells. Analysis of gene expression showed that the genes involved in the TP53 pathway were up-regulated in TK6 cells but not in WTK-1 cells. The differential responses to 5-FU between these cell lines appeared to be due to the difference in the TP53 gene status, thus providing a molecular basis for the bioassays using these cell lines in the toxicology field. Our results indicate that the clinical efficacy of 5-FU chemotherapy may depend on the TP53 genotype

“Input/output cytokines” in epidermal keratinocytes and the involvement in inflammatory skin diseases

Considering the role of epidermal keratinocytes, they occupy more than 90% of the epidermis, form a physical barrier, and also function as innate immune barrier. For example, epidermal keratinocytes are capable of recognizing various cytokines and pathogen-associated molecular pattern, and producing a wide variety of inflammatory cytokines, chemokines, and antimicrobial peptides. Previous basic studies have shown that the immune response of epidermal keratinocytes has a significant impact on inflammatory skin diseases. The purpose of this review is to provide foundation of knowledge on the cytokines which are recognized or produced by epidermal keratinocytes. Since a number of biologics for skin diseases have appeared, it is necessary to fully understand the relationship between epidermal keratinocytes and the cytokines. In this review, the cytokines recognized by epidermal keratinocytes are specifically introduced as "input cytokines", and the produced cytokines as "output cytokines". Furthermore, we also refer to the existence of biologics against those input and output cytokines, and the target skin diseases. These use results demonstrate how important targeted cytokines are in real skin diseases, and enhance our understanding of the cytokines

Novel animal model of combined generalized and focal epilepsy

Thioredoxin, encoded by Txn1, is a critical antioxidant that protects against oxidative damage by regulating the dithiol/disulfide balance of interacting proteins. We recently discovered the Adem rat, an epileptic rat harboring the Txn1-F54L mutation, characterized by wild running and vacuolar degeneration in the midbrain. This study aimed to characterize the classification of epilepsy in Adem rats. We performed simultaneous video-electroencephalographic recordings, magnetic resonance imaging, neurotransmitter measurements using gas chromatography–mass spectrometry (GC-MS), and immunohistochemistry. Adem rats exhibited absence, tonic, and focal seizures. The type of epilepsy was classified as combined generalized and focal epilepsy. Neurotransmitters in the midbrain and cortex were measured at 3 weeks of age, when neuronal cell death occurs in the midbrain. The results of GC-MS ruled out the dominance of the excitatory system in the midbrain and cortex of Adem rats. Activation of astrocytes and microglia was more pronounced at 5 weeks of age, at which time epileptic seizures occurred frequently. The underlying pathology in Adem rats remains unknown. However, glial cell activation and inflammation may play a significant role in the occurrence of epilepsy

Antinociceptive Effects of Intrathecal Landiolol Injection in a Rat Formalin Pain Model

Perioperative beta-blocker administration has recently been recommended for patients undergoing cardiac or other surgery due to the beneficial cardiovascular effects of these agents. In addition, some studies have reported that perioperatively administered beta-blockers also have analgesic effects. In this study, to investigate the antinociceptive effects and the analgesic profile of landiolol, we examined the effects of intrathecal landiolol administration on nociceptive pain behavior and c-fos mRNA expression (a neural marker of pain) in the spinal cord using a rat formalin model. We found that pain-related behavior was inhibited by intrathecal landiolol administration. Moreover, the increase in c-fos mRNA expression on the formalin-injected side was less pronounced in rats administered landiolol than in saline administered controls. Thus, intrathecal administration of landiolol exhibited antinociceptive effects. Further investigation of the antinociceptive mechanism of landiolol is required

Eradication of Hepatitis C Virus Subgenomic Replicon by Interferon Results in Aberrant Retinol-Related Protein Expression

Hepatitis C virus (HCV) infection induces several changes in hepatocytes, such as oxidative stress, steatosis, and hepatocarcinogenesis. Although considerable progress has been made during recent years, the mechanisms underlying these functions remain unclear. We employed proteomic techniques in HCV replicon-harboring cells to determine the effects of HCV replication on host-cell protein expression. We examined two-dimensional electrophoresis (2-DE) and mass spectrometry to compare and identify differentially expressed proteins between HCV subgenomic replicon-harboring cells and their “cured” cells. One of the identified proteins was confirmed using enzyme-linked immunosorbent assay (ELISA) and Western blot analysis. Full-length HCV genome RNA replicating and cured cells were also assessed using ELISA. Replicon-harboring cells showed higher expression of retinal dehydrogenase 1 (RALDH-1), which converts retinol to retinoic acid, and the cured cells showed higher expression of retinol-binding protein (RBP), which transports retinol from the liver to target tissues. The alteration in RBP expression was also confirmed by ELISA and Western blot analysis. We conclude that protein expression profiling demonstrated that HCV replicon eradication affected retinol-related protein expression

Truncated SSX Protein Suppresses Synovial Sarcoma Cell Proliferation by Inhibiting the Localization of SS18-SSX Fusion Protein

Synovial sarcoma is a relatively rare high-grade soft tissue sarcoma that often develops in the limbs of young people and induces the lung and the lymph node metastasis resulting in poor prognosis. In patients with synovial sarcoma, specific chromosomal translocation of t(X; 18) (p11.2; q11.2) is observed, and SS18-SSX fusion protein expressed by this translocation is reported to be associated with pathogenesis. However, role of the fusion protein in the pathogenesis of synovial sarcoma has not yet been completely clarified. In this study, we focused on the localization patterns of SS18-SSX fusion protein. We constructed expression plasmids coding for the full length SS18-SSX, the truncated SS18 moiety (tSS18) and the truncated SSX moiety (tSSX) of SS18-SSX, tagged with fluorescent proteins. These plasmids were transfected in synovial sarcoma SYO-1 cells and we observed the expression of these proteins using a fluorescence microscope. The SS18-SSX fusion protein showed a characteristic speckle pattern in the nucleus. However, when SS18-SSX was co-expressed with tSSX, localization of SS18-SSX changed from speckle patterns to the diffused pattern similar to the localization pattern of tSSX and SSX. Furthermore, cell proliferation and colony formation of synovial sarcoma SYO-1 and YaFuSS cells were suppressed by exogenous tSSX expression. Our results suggest that the characteristic speckle localization pattern of SS18-SSX is strongly involved in the tumorigenesis through the SSX moiety of the SS18-SSX fusion protein. These findings could be applied to further understand the pathogenic mechanisms, and towards the development of molecular targeting approach for synovial sarcoma

Novel analgesics targeting brain-derived neurotrophic factor for neuropathic pain

　Brain-derived neurotrophic factor (BDNF) is necessary for the development, growth, and maintenance of nerve cells. BDNF is expressed in the dorsal root ganglion (DRG); binds to the Tropomyosin receptor kinasa B (TrkB) receptor, which has a tyrosine kinase domain, in the spinal cord; and plays an important role as a pain modulator. BDNF expression is increased in various types of pain, including acute pain, neuropathic pain, and cancer pain. Activation of the BDNF–TrkB pathway transmits pain information. In order to inhibit the BDNF–TrkB pathway, by sequestering BDNF, we constructed a cDNA expression plasmid encoding the extracellular region of rat TrkB fused to enhanced green fluorescent protein (EGFP). When the expression plasmid vector was administered to rat models of neuropathic pain, induced by spinal nerve ligation, statistically significant relief of pain was observed in terms of a 50% paw-withdrawal threshold using the von Frey test. The expression of TrkB-EGFP mRNA was detected in L5 lumbar vertebral nerves by quantitative reverse transcriptase polymerase chain reaction. To verify the pain-suppressive effect of the expression vector, truncated TrkB protein, without EGFP, was purified, and administered to pain model rats. A statistically significant suppressive effect of the truncated TrkB protein on neuropathic pain was observed 2 days after administration. The pain-suppressive effect of the truncated TrkB protein was more effective than that of the TrkB-Fc chimera protein and lasted longer than that of the TrkB antagonist ANA-12. Our results suggested that the truncated TrkB cDNA expression vector and truncated TrkB protein could be used as molecular targeted drugs in patients with neuropathic pain