BACKGROUND:Chronic kidney disease (CKD) is a global health burden with high prevalence and poor prognosis. Although oxidative stress and mitochondrial dysfunction have been implicated in its pathogenesis, in vivo causal evidence remains limited. Thioredoxin (Trx), encoded by Txn1, is a redox-active protein that plays a central role in controlling oxidative stress and maintaining intracellular redox homeostasis. METHODS:To address this gap, we investigated the lifelong phenotypes of Txn1-F54L mutant rats harboring approximately one-third of the normal Trx activity. These rats were generated via N-ethyl-N-nitrosourea mutagenesis and validated by clustered regularly interspaced palindromic repeat (CRISPR)/CRISPR-associated protein 9 genome editing. Comprehensive analyses included biochemical testing, histopathology, immunohistochemistry, transmission electron microscopy, RNA-sequencing, western blotting, and cytokine profiling. RESULTS:Txn1-F54L mutant rats spontaneously developed progressive CKD, with median survival times of 110-119 days for homozygotes and 303-346 days for heterozygotes. Their clinical features-elevated blood urea nitrogen, hypoalbuminemia, hypercholesterolemia, hypertension, and arterial medial sclerosis-closely resembled those of human CKD. Histopathological evaluation revealed extensive tubular injury, interstitial fibrosis, and glomerulosclerosis. Transcriptomic profiling identified 3,418 differentially expressed genes significantly enriched in immune activation and fibrosis pathways. Mitochondrial dysfunction was prominent in proximal tubules, accompanied by oxidative stress accumulation and concurrent activation of regulated cell death pathways (apoptosis, necroptosis, and pyroptosis). Elevated serum levels of interleukin-1β, interleukin-6, and interferon-γ indicated systemic inflammation. CONCLUSIONS:Our findings demonstrate that lifelong Trx deficiency induces oxidative stress-mediated mitochondrial dysfunction and regulated cell death, leading to inflammation and progressive CKD. This study establishes the Txn1 mutant rat as a valuable spontaneous CKD model, providing translational insights and a platform for developing therapeutic strategies targeting oxidative stress-induced pathways.

Netherton syndrome (NS) is a rare congenital ichthyosis caused by loss-of-function mutations in the SPINK5 gene, leading to defective expression of the serine protease inhibitor LEKTI. Dysregulated epidermal protease activity results in impaired skin barrier function and chronic inflammation, accompanied by complex immune profiles. NS patients commonly show activation of the inflammatory axis, centered on IL-17 and IL-36, in the skin and blood, and show a psoriasis-like shift to Th17. Conversely, the immune profile differs depending on the clinical type, with ichthyosis linearis circumflexa type characterized by complement activation and Th2-type allergic responses, and scaly erythroderma type characterized by a type I IFN signature and Th9-type allergic responses. While symptomatic treatments such as emollients and topical corticosteroids have been the mainstay of care, recent advances have opened new therapeutic avenues involving biologic agents and oral small-molecule immunomodulators. This review provides a comprehensive overview of the current clinical landscape and future directions of biologics (e.g., dupilumab, secukinumab, ustekinumab) and small-molecule therapies (e.g., JAK inhibitors such as tofacitinib, baricitinib, and upadacitinib) in the treatment of NS. Though evidence remains limited to case reports and small series, preliminary data suggest that cytokine-targeted interventions-particularly those inhibiting IL-4, IL-13, IL-17, IL-36, and JAK pathways-may offer tangible clinical benefits. Well-designed clinical trials and mechanistic investigations are crucial to establishing their place in NS management.

Thioredoxin is a ubiquitous redox protein that acts as an electron donor via its conserved dithiol motif (C32GPC35), catalyzing dithiol-disulfide exchange to regulate the redox state of target proteins. It supports antioxidant defense via peroxiredoxins, facilitates DNA synthesis by donating electrons to ribonucleotide reductase, and regulates redox-sensitive signaling pathways, including those controlling transcription and apoptosis. Neuronal degeneration and chronic kidney disease have been observed in Txn-F54L mutant rats; however, the details of why the Txn mutation causes these phenomena remain unknown. The present study aimed to elucidate the functional and structural changes caused by the F54L mutation. The Thioredoxin-F54L showed less insulin-reducing activity and more thermosensitivity to denaturation in the body temperature range compared to the wild type. The crystal structure revealed that F54 forms hydrophobic interactions with the surrounding hydrophobic amino acids. In addition, molecular dynamics simulation predicts increased fluctuations around the F54L mutation and a tendency for the distance between residues C32 and C35 at the catalytic center to be widened. The increased distance between residues C32 and C35 of the catalytic center may affect the reducing activity of the enzyme on the substrate. The finding that Thioredoxin-F54L is prone to denaturation at normal body temperature may reduce the normally functioning Thioredoxin. These molecular characteristics of Thioredoxin-F54L may be related to brain and kidney disease development in the Txn-F54L rats.

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.

Oxidative stress plays a significant role in the progression of chronic kidney disease. Thioredoxin 1 (Txn1) is one of the enzymatic antioxidants to regulate redox balance. However, the molecular mechanisms by Txn1 affects renal homeostasis remain unclear. This study aimed at elucidating the pathophysiology of Txn1 mutations in renal function. We used rats with the Txn1- F54L mutation generated by N-ethyl-N-nitrosourea mutagenesis. Laboratory tests and pathological examinations were performed in wild-type (WT) rats and in rats with heterozygous and homozygous Txn1 -F54L mutations. We performed RNA-seq analysis of the WT and homozygotes. To confirm phenotypic reproducibility, the Txn1 -F54L mutation was generated in rats with different genetic backgrounds using CRISPR/Cas9 genome editing technology. Txn1 -F54L mutant rats exhibited progressive albuminuria, hypoalbuminemia, hypercholesterolemia, and hypertension. Renal pathology revealed marked nephrosclerosis, tubular dilatation, interstitial fibrosis, and decreased number of mitochondria, mainly in the paroxysmal tubules. We confirmed a similar phenotype of chronic kidney disease (CKD) in different rat strains. RNA-seq showed the downregulation of mitochondria-related genes and significant upregulation of genes associated with inflammation, pyroptosis, apoptosis, and necroptosis in mutant rats. Our results show that the Txn1 mutation is a monogenic cause of CKD termination. The underlying pathology involves several regulated cell-death pathways. Thus, our study provides a new animal model of oxidative stress-induced CKD. Txn1- F54L mutant rats will aid in developing therapeutic strategies for CKD. Translational Statement We found that the deficiency of thioredoxin (Txn1), which regulates oxidative stress, spontaneously caused chronic kidney disease (CKD) in rats. The Txn1-F54L ( Adem ) rat is a new model of CKD with complications such as anemia, hypertension, and cardiovascular disease. Renal pathology revealed nephrosclerosis, interstitial fibrosis, and mitochondrial damage. The molecular basis of the underlying pathologies included inflammation, pyroptosis, apoptosis, and necroptosis. These pathological changes are partially linked to renal diseases such as diabetic nephropathy, hypertensive nephrosclerosis, and ischemic reperfusion injury. Adem rats could help understand the common pathological mechanisms of these renal diseases and develop therapeutic strategies.

Thioredoxin, encoded by Txn1, acts as a critical antioxidant in the defense against oxidative stress by regulating the dithiol/disulfide balance of interacting proteins. The role of thioredoxin in the central nervous system (CNS) is largely unknown. A phenotype-driven study of N-ethyl-N-nitrosourea-mutated rats with wild-running seizures revealed the importance of Txn1 mutations in CNS degeneration. Genetic mapping identified Txn1-F54L in the epileptic rats. The insulin-reducing activity of Txn1-F54L was approximately one-third of that of the wild-type (WT). Bilateral symmetrical vacuolar degeneration in the midbrain, mainly in the thalamus and the inferior colliculus, was observed in the Txn1-F54L rats. The lesions displayed neuronal and oligodendrocytic cell death. Neurons in Txn1-F54L rats showed morphological changes in the mitochondria. Vacuolar degeneration peaked at five weeks of age, and spontaneous repair began at seven weeks. The TUNEL assay showed that fibroblasts derived from homozygotes were susceptible to cell death under oxidative stress. In five-week-old WT rats, energy metabolism in the thalamus was significantly higher than that in the cerebral cortex. In conclusion, in juvenile rats, Txn1 seems to play an essential role in reducing oxidative stress in the midbrains with high energy metabolism.

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.

Atopic dermatitis (AD) is a chronic inflammatory skin disease; the three major factors responsible for AD, i.e., epidermal barrier dysfunction, allergic inflammation, and itching, interact with each other to form a pathological condition. Excessive protease activities are characteristic abnormalities that affect the epidermal barrier in patients with AD. In normal skin, epidermal serine protease activities are controlled by kallikrein-related peptidases (KLKs) and their inhibitors, including lympho-epithelial Kazal-type-related inhibitor (LEKTI). In AD lesions, KLKs are excessively expressed, which results in the enhancement of epidermal serine protease activities and facilitates the invasion by allergens and microorganisms. In addition, some KLKs can activate protease-activated receptor 2 (PAR2) in epidermal keratinocytes and peripheral nerves, resulting in the induction of inflammation and itching. Furthermore, in AD patients with single nucleotide polymorphism (SNP) such as E420K and D386N of SPINK5 which encodes LEKTI, LEKTI function is attenuated, resulting in the activation of KLKs and easy invasion by allergens and microorganisms. Further analysis is needed to elucidate the detailed mechanism underlying the control of serine protease activities, which may lead to the development of new therapeutic and prophylactic agents for AD.

A novel proteasome deubiquitinase inhibitor, VLX1570, has been highlighted as a promising therapeutic agent mainly for lymphoid neoplasms and solid tumors. We examined in vitro effects of VLX1570 on eight myeloid and three lymphoid leukemia cell lines. From cell culture studies, 10 out of 11 cell lines except K562 were found to be susceptible to VLX1570 treatment and it inhibited cell growth mainly by apoptosis. Next, to identify the signaling pathways associated with apoptosis, we performed gene expression profiling using HL-60 with or without 50 nmol/L of VLX1570 for 3 hours and demonstrated that VLX1570 induced the genetic pathway involved in "heat shock transcription factor 1 (HSF1) activation", "HSF1 dependent transactivation", and "Regulation of HSF1 mediated heat shock response". VLX1570 increased the amount of high molecular weight polyubiquitinated proteins and the expression of HSP70 as the result of the suppression of ubiquitin proteasome system, the expression of heme oxygenase-1, and the amount of phosphorylation in JNK and p38 associated with the generation of reactive oxygen species (ROS) induced apoptosis and the amount of phosphorylation in eIF2α, inducing the expression of ATF4 and endoplasmic reticulum (ER) stress dependent apoptosis protein, CHOP, and the amount of phosphorylation slightly in IRE1α, leading to increased expression of XBP-1s in leukemia cell lines. In the present study, we demonstrate that VLX1570 induces apoptosis and exerts a potential anti-leukemic effect through the generation of ROS and induction of ER stress in leukemia cell lines.

Thioredoxin (TXN), encoded by Txn1 , acts as a critical antioxidant in the defense against oxidative stress by regulating the dithiol/disulfide balance of interacting proteins. The role of TXN in the central nervous system (CNS) is largely unknown. A phenotype-driven study of N -ethyl- N -nitrosourea-mutated rats with running seizures at around five-week of age revealed the relevance of Txn1 mutations to CNS disorders. Genetic mapping identified Txn1 -F54L in epileptic rats. The insulin-reducing activity of Txn1 -F54L rats was approximately one-third that of the wild-type. Vacuolar degeneration in the midbrain, mainly in the thalamus and the inferior colliculus, was observed in the Txn1 -F54L rats. The lesions displayed neuronal and oligodendrocyte cell death. Neurons in Txn1 -F54L rats showed morphological changes in the mitochondria. Vacuolar degeneration began at three weeks of age, and spontaneous repair began at seven weeks; a dramatic change from cell death to repair occurred in the midbrain during a restricted period. In conclusion, Txn1 is essential for the development of the midbrain in juvenile rats.

Interleukin (IL) 23 (p19/p40) plays a critical role in the pathogenesis of psoriasis and is upregulated in psoriasis skin lesions. In clinical practice, anti-IL-23Ap19 antibodies are highly effective against psoriasis. IL-39 (p19/ Epstein-Barr virus-induced (EBI) 3), a newly discovered cytokine in 2015, shares the p19 subunit with IL-23. Anti-IL-23Ap19 antibodies may bind to IL-39; also, the cytokine may contribute to the pathogenesis of psoriasis. To investigate IL23Ap19- and/or EBI3-including cytokines in psoriatic keratinocytes, we analyzed IL-23Ap19 and EBI3 expressions in psoriasis skin lesions, using immunohistochemistry and normal human epidermal keratinocytes (NHEKs) stimulated with inflammatory cytokines, using quantitative real-time polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA), and liquid chromatography-electrospray tandem mass spectrometry (LC-Ms/Ms). Immunohistochemical analysis showed that IL-23Ap19 and EBI3 expressions were upregulated in the psoriasis skin lesions. In vitro, these expressions were synergistically induced by the triple combination of tumor necrosis factor (TNF)-α, IL-17A, and interferon (IFN)-γ, and suppressed by dexamethasone, vitamin D3, and acitretin. In ELISA and LC-Ms/Ms analyses, keratinocyte-derived IL-23Ap19 and EBI3, but not heterodimeric forms, were detected with humanized anti-IL-23Ap19 monoclonal antibodies, tildrakizumab, and anti-EBI3 antibodies, respectively. Psoriatic keratinocytes may express IL-23Ap19 and EBI3 proteins in a monomer or homopolymer, such as homodimer or homotrimer.

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.

Effective treatment of neuropathic pain is challenging as its underlying mechanism remains largely unknown. Recently, the participation of brain-derived neurotrophic factor (BDNF) in neuropathic pain has been attracting increased attention. BDNF binds to a member of the tyrosine kinase receptor family, the TrkB receptor, that is specific for BDNF and is the transmembrane receptor on the posterior horn of spinal cord. In the present study, we purified two proteins that included the BDNF-binding domain of TrkB (eTrkB) and eTrkB coupled with a liposomal outer surface (liposomal eTrkB) in order to inhibit the BDNF-TrkB pathway in neuropathic pain. Results of the pull-down assay showed that eTrkB was bound to BDNF. We investigated the neuropathic pain suppression effect of this purified protein by its intrathecal administration in a rat neuropathic pain model. Mechanical and thermal hyperalgesia induced by L5 lumbar nerve ligation was markedly suppressed by treatment with eTrkB protein. Furthermore, we showed a prolonged algetic inhibition by liposomal eTrkB protein treatment. In conclusion, this study suggests that eTrkB, which sequesters endogenous BDNF and inhibits the BDNF-TrkB pathway, may prove to be a novel analgesic to treat neuropathic pain.

Lympho-epithelial Kazal-type-related inhibitor (LEKTI) is a large multidomain serine protease inhibitor that is expressed in epidermal keratinocytes. Nonsense mutations of the SPINK5 gene, which codes for LEKTI, cause Netherton syndrome, which is characterized by hair abnormality, ichthyosis, and atopy. A single nucleotide polymorphism (SNP) of SPINK5, p.K420E, is reported to be associated with the pathogenesis of atopic dermatitis (AD). We studied all 34 exons of the SPINK5 gene in Japanese 57 AD patients and 50 normal healthy controls. We detected nine nonsynonymous variants, including p.K420E; these variants had already been registered in the SNP database. Among them, p.R654H (n=1) was found as a heterozygous mutation in the AD patients, but not in the control. No new mutation was detected. We next compared the data of the AD patients with data from the Human Genetic Variation Database provided by Kyoto University; a significant difference was found in the frequency of the p.S368N genotype distribution. PolyPhen-2 and SIFT, two algorithms for predicting the functional effects of amino acid substitutions, showed significant scores for p.R654H. Therefore, R654H might be a risk factor for epidermal barrier dysfunction in some Japanese AD patients.

Human RAD17 acts as an activator of checkpoint signals in response to DNA damage. Here we evaluated the association of hRAD17 Leu546Arg (rs1045051), a missense single nucleotide polymorphism, with the risk of colorectal cancer (CRC) in relation to smoking and alcohol consumption habits in 212 CRC patients and 1,142 cancer-free controls in a case-control study conducted in Japan. The results showed that the hRAD17 Leu/Arg genotype compared to the Leu/Leu genotypes was significantly associated with the protective effect on CRC risk with the adjusted odds ratio (OR) of 0.68 [95% confidence interval (CI): 0.49-0.95, p=0.024], and the males with the Arg/Arg genotype had a greater risk of CRC compared to those with the Leu/Leu and Leu/Arg genotypes (OR=1.87, 95%CI 1.03-3.40, p=0.04). In stratified studies, the protective effect of the Leu/Arg genotype on CRC risk was markedly higher in the light smokers (< 20 pack years) (OR=0.61, 95%CI 0.40-0.94, p=0.024) and the rectal cancer patients (OR=0.49, 95%CI 0.31-0.78, p=0.003). The risk of the Arg/Arg genotype was associated with heavy smoking (≥ 20 pack-years) (OR=2.24, 95%CI 1.09-4.61, p=0.03). These findings suggest that the genetic variant of hRAD17 Leu546Arg polymorphism has a significant effect on CRC susceptibility in Japanese.

Right © 2014 The Authors. Epilepsia published by Wiley Periodicals, Inc. on behalf of International League Against Epilepsy.; This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. Type Journal Article