Anti-rheumatic property and physiological safety of KMU-11342 in in vitro and in vivo models.

Rheumatoid arthritis (RA) is a chronic, systemic inflammatory disorder characterized by joint destruction due to synovial hypertrophy and the infiltration of inflammatory cells. Despite substantial progress in RA treatment, challenges persist, including suboptimal treatment responses and adverse effects associated with current therapies. This study investigates the anti-rheumatic capabilities of the newly identified multi-protein kinase inhibitor, KMU-11342, aiming to develop innovative agents targeting RA. In this study, we synthesized the novel multi-protein kinase inhibitor KMU-11342, based on indolin-2-one. We assessed its cardiac electrophysiological safety using the Langendorff system in rat hearts and evaluated its toxicity in zebrafish in vivo. Additionally, we examined the anti-rheumatic effects of KMU-11342 on human rheumatoid arthritis fibroblast-like synoviocytes (RA-FLS), THP-1 cells, and osteoclastogenesis in RAW264.7 cells. KMU-11342 demonstrated the ability to inhibit LPS-induced chemokine inhibition and the upregulation of pro-inflammatory cytokines, cyclooxygenase-2, inducible nitric oxide synthase, p-IKKα/ß, p-NF-κB p65, and the nuclear translocation of NF-κB p65 in RA-FLS. It effectively suppressed the upregulation of NLR family pyrin domain containing 3 (NLRP3) and caspase-1 cleavage. Furthermore, KMU-11342 hindered the activation of osteoclast differentiation factors such as RANKL-induced TRAP, cathepsin K, NFATc-1, and c-Fos in RAW264.7 cells. KMU-11342 mitigates LPS-mediated inflammatory responses in THP-1 cells by inhibiting the activation of NLRP3 inflammasome. Notably, KMU-11342 exhibited minimal cytotoxicity in vivo and electrophysiological cardiotoxicity ex vivo. Consequently, KMU-11342 holds promise for development as a therapeutic agent in RA treatment.

Pathogen-Associated Molecular Pattern-Triggered Immunity Involves Proteolytic Degradation of Core Nonsense-Mediated mRNA Decay Factors During the Early Defense Response.

Nonsense-mediated mRNA decay (NMD), an mRNA quality control process, is thought to function in plant immunity. A subset of fully spliced (FS) transcripts of Arabidopsis (Arabidopsis thaliana) resistance (R) genes are upregulated during bacterial infection. Here, we report that 81.2% and 65.1% of FS natural TIR-NBS-LRR (TNL) and CC-NBS-LRR transcripts, respectively, retain characteristics of NMD regulation, as their transcript levels could be controlled posttranscriptionally. Both bacterial infection and the perception of bacteria by pattern recognition receptors initiated the destruction of core NMD factors UP-FRAMESHIFT1 (UPF1), UPF2, and UPF3 in Arabidopsis within 30 min of inoculation via the independent ubiquitination of UPF1 and UPF3 and their degradation via the 26S proteasome pathway. The induction of UPF1 and UPF3 ubiquitination was delayed in mitogen-activated protein kinase3 (mpk3) and mpk6, but not in salicylic acid-signaling mutants, during the early immune response. Finally, previously uncharacterized TNL-type R transcripts accumulated in upf mutants and conferred disease resistance to infection with a virulent Pseudomonas strain in plants. Our findings demonstrate that NMD is one of the main regulatory processes through which PRRs fine-tune R transcript levels to reduce fitness costs and achieve effective immunity.

KMU-1170, a Novel Multi-Protein Kinase Inhibitor, Suppresses Inflammatory Signal Transduction in THP-1 Cells and Human Osteoarthritic Fibroblast-Like Synoviocytes by Suppressing Activation of NF-κB and NLRP3 Inflammasome Signaling Pathway.

Protein kinases regulate protein phosphorylation, which are involved in fundamental cellular processes such as inflammatory response. In this study, we discovered a novel multi-protein kinase inhibitor, KMU-1170, a derivative of indolin-2-one, and investigated the mechanisms of its inflammation-inhibiting signaling in both THP-1 cells and human osteoarthritic fibroblast-like synoviocytes (FLS). We demonstrated that in THP-1 cells, KMU-1170 inhibited lipopolysaccharide (LPS)-induced upregulation of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), and, furthermore, suppressed LPS-induced phosphorylation of transforming growth factor-ß-activated kinase 1, JNK, ERK, inhibitor of NF-κB kinase α/ß (IKKα/ß), and NF-κB p65 as well as nuclear translocation of NF-κB p65. Moreover, KMU-1170 suppressed LPS-induced upregulation of proinflammatory cytokines such as IL-1ß, TNF-α, and IL-6, and, notably, inhibited LPS-induced upregulation of the NLRP3 inflammasome in THP-1 cells. Importantly, KMU-1170 attenuated LPS-mediated inflammatory responses in human osteoarthritic FLS, such as the upregulation of IL-1ß, TNF-α, IL-6, iNOS, and COX-2 and the phosphorylation of IKKα/ß and NF-κB p65. Collectively, these results suggest that KMU-1170 inhibits inflammatory signal transduction and could be developed as a potential anti-inflammatory agent.

Proteomic analysis of human synovial fluid reveals potential diagnostic biomarkers for ankylosing spondylitis.

BACKGROUND: Ankylosing spondylitis (AS) is a chronic inflammatory rheumatic disease affecting the axial skeleton and peripheral joints. The etiology of this disease remains poorly understood, but interactions between genetic and environmental factors have been implicated. The present study identified differentially expressed proteins in the synovial fluid (SF) of AS patients to elucidate the underlying cause of AS. METHODS: A cohort of 40 SF samples from 10 AS and 10 each of rheumatoid arthritis (RA), gout, and osteoarthritis (OA) patients were analyzed by liquid chromatography tandem mass spectrometry (LC-MS/MS) to identify differentially expressed proteins specific to AS. The label-free LC-MS/MS results were verified by western blotting. RESULTS: We identified 8 proteins that were > 1.5-fold upregulated in the SF of AS patients compared to that of the disease control groups, including HP, MMP1, MMP3, serum amyloid P-component (APCS), complement factor H-related protein 5 (CFHR5), mannose-binding lectin 2 (MBL2), complement component C9 (C9), and complement C4-A (C4A). CFHR5 and C9 were previously found in serum from AS patients, while APCS was previously found in SF as well as in serum. However, the present study has identified C4A, and MBL2 as potential AS biomarkers for the first time. The expression levels of MMP3, C9, and CFHR5 were verified in AS SF using western blotting. CONCLUSION: We performed quantitative comparative proteomic analysis using by LC-MS/MS of the SF from four disease states: RA, gout, and OA. This systematic comparison revealed novel differentially expressed proteins in AS SF, as well as two previously reported candidate biomarkers. We further verified the expression of MMP3, C9 and CFHR5 by western blot. These proteins may serve as diagnostic or prognostic biomarkers in patients with AS, and may thus improve the clinical outcomes of this serious disease.

The association of disease activity, pro-inflammatory cytokines, and neurotrophic factors with depression in patients with rheumatoid arthritis.

Inflammation and trophic factors (brain-derived neurotrophic factor [BDNF], vascular endothelial growth factor, glial cell line-derived neurotrophic factor, and insulin-like growth factor-1) are associated with depression in the general population. Rheumatoid arthritis (RA) is a chronic representative inflammatory autoimmune disease; however, the association of disease activity, pro-inflammatory cytokines, and neurotrophic factors with depression has not been sufficiently investigated. Therefore, we determined the prevalence of depression and risk factors for depression and deterioration of depressive symptoms in RA patients. In addition, we analyzed the association between disease activity, pro-inflammatory cytokines, trophic factors, and depression in RA (N = 474). Demographic and laboratory data were examined, and routine assessment of patient index data 3 (RAPID 3) and disease activity score 28-joint count C-reactive protein (DAS 28-CRP) was performed to assess disease activity of RA. Depression was measured using the Korean version of the Beck Depression Inventory-second edition (K-BDI II). A K-BDI score ≥18 was considered the cut-off for depression in accordance with a previous validation study. The serum level of pro-inflammatory cytokines and neurotrophic factors was assessed by enzyme-linked immune sorbent assay. The prevalence of depression was 32.4% in patients with RA. The severity of disease activity of RA (RAPID 3 score [OR 2.34; 95% confidence interval, CI 1.22-4.51], DAS 28-CRP [≥3.2] [OR 1.60, 95% CI 1.01-2.53]) and severity of fatigue (OR 1.26 95% CI 1.15-1.38) were associated with depression and deterioration of depressive symptoms in the multivariate analysis. Among the components of RAPID 3 and DAS 28-CRP, patient assessment for global health and abilities for daily performance were more related to depression. The level of pro-inflammatory cytokines (IL-1ß, IL-6, TNF-alpha) was not related to depression. The level of BDNF was significantly lower in RA patients with depression and was negatively correlated with K-BDI II score. Depression was related with the level of fatigue, low expression of BDNF, and high RA disease activity, which was associated with impaired ability to perform activities of daily life. Strict control of fatigue and disease activity to improve one's capacity to perform daily life activities would be important to regulate depression. The level of BDNF might be one of the possible biomarkers to predict or monitor depression in patients with RA.

The Pepper WPP Domain Protein, CaWDP1, Acts as a Novel Negative Regulator of Drought Stress via ABA Signaling.

Plants are constantly challenged by various environmental stresses, including high salinity and drought, and they have evolved defense mechanisms to counteract the deleterious effects of these stresses. The plant hormone ABA regulates plant growth and developmental processes and mediates abiotic stress responses. Here, we report the identification and characterization of a novel CaWDP1 (Capsicum annuum) protein. The expression of CaWDP1 in pepper leaves was induced by ABA, drought and NaCl treatments, suggesting its role in the abiotic stress response. CaWDP1 proteins show conserved sequence homology with other known WDP1 proteins, and they are localized in the nucleus and cytoplasm. We generated CaWDP1-silenced peppers via virus-induced gene silencing (VIGS). We evaluated the responses of these CaWDP1-silenced pepper plants and CaWDP1-overexpressing (OX) transgenic Arabidopsis plants to ABA and drought. CaWDP1-silenced pepper plants displayed enhanced tolerance to drought stress, and this was characterized by low levels of leaf water loss in the drought-treated leaves. In contrast to CaWDP1-silenced plants, CaWDP1-OX plants exhibited an ABA-hyposensitive and drought-susceptible phenotype, which was accompanied by high levels of leaf water loss, low leaf temperatures, increased stomatal pore size and low expression levels of stress-responsive genes. Our results indicate that CaWDP1, a novel pepper negative regulator of ABA, regulates the ABA-mediated defense response to drought stress.

ABCG2 Polymorphism Is Associated with Hyperuricemia in a Study of a Community-Based Korean Cohort.

The purpose of the present study was to find novel loci associated with hyperuricemia using data from a genome-wide association study (GWAS) conducted on healthy Koreans. We conducted a GWAS using data from a community-based cohort study where 3,647 subjects aged 40-89 were recruited by the Korea National Institute of Health (KNIH). The community-based cohort consisted of subjects who did not suffer from any of 6 major diseases (hypertension, hyperlipidemia, diabetes, heart diseases, brain diseases, and cancers). Epidemiologic information includes 249 traits such as epidemiological surveys, physical examinations, and laboratory tests. A total of 3,647 participants, including 234 hyperuricemia cases (serum uric acid [SUA] level was 7 mg/dL or higher) and 3,413 controls, were genotyped by Illumina HumanOmni1-Quad BeadChip GWAS array at KNIH. In the multivariate regression analysis of clinical variables, significant variables associated with hyperuricemia were male gender (odds ratio [OR], 5.526; P = 3.2 × 10⁻¹°), old age (OR, 1.017; P = 0.040), high body mass index (BMI) (OR, 1.147; P = 5.4 × 10⁻7), current alcohol intake (OR, 2.413; P = 4.7 × 10⁻7), and high creatinine (OR, 1.647; P = 1.6 × 10⁻¹³). We identified a hyperuricemia susceptible loci (rs2054576 in ABCG2, OR, 1.883; P = 4.7 × 10⁻8) that passed a genome-wide significance threshold, adjusted by clinical variables (male, age, BMI, current alcohol, and creatinine). It was first identified that rs2054576 in ABCG2 is associated with hyperuricemia. Our results should be validated through replication studies among other Korean subjects or various ethnic groups.

Polymorphisms of the TRPV2 and TRPV3 genes associated with fibromyalgia in a Korean population.

OBJECTIVE: Researchers continue to gather evidence that transient receptor potential vanilloid (TRPV) channels contribute towards pain signalling pathways. However, it is unknown whether polymorphisms of the TRPV gene are associated with FM. For the first time, we investigated the association between the polymorphisms of the TRPV2 and TRPV3 genes, FM susceptibility and the severity of the symptoms. METHODS: A total of 409 patients with FM and 423 controls were enrolled from 10 medical centres that participated in the Korean nationwide FM survey. The alleles and genotypes at three positions [rs3813768(C > G), rs8121(C > T) and rs1129235(C > A)] in the TRPV2 gene and two positions [rs7216486 (G > A) and rs395357(C > T)] in the TRPV3 gene were genotyped. RESULTS: The frequencies of the alleles and genotypes of individual TRPV2 and TRPV3 genes were not significantly associated with FM susceptibility. However, the GTA haplotype of TRPV2 showed a defence against FM susceptibility (P = 0.035). In addition, polymorphisms of TRPV3 were associated with symptom severity in FM patients. The single nucleotide polymorphism rs395357 of TRPV3 was associated with the scores of the Brief Fatigue Inventory (P = 0.017) in FM patients. Furthermore, haplotypes of TRPV3 were associated with the Brief Fatigue Inventory and the 36-item Short-Form Health Survey mental health summary scores (P = 0.036). CONCLUSION: This study was the first to evaluate the associations of TRPV gene polymorphisms with FM. Our results suggest that certain TRPV2 haplotypes may have a protective role against FM and that some genotypes and haplotypes of TRPV3 contribute towards the symptoms of FM.

Severity of fibromyalgia symptoms is associated with socioeconomic status and not obesity in Korean patients.

OBJECTIVES: Several studies conducted in Western countries have shown that obese or overweight patients with fibromyalgia (FM) exhibit more severe symptoms than patients of normal weight. However, there has been no study on the relationship between obesity and FM symptom severity in Asian patients. In this study, we evaluated the association between obesity, and other related factors such as socioeconomic status (SES), and FM symptom severity in Korean patients. METHODS: A total of 343 participants were enrolled in this prospective cohort study, which used a nationwide survey of FM patients who were followed on an annual basis. We investigated health-related quality of life (QoL) and associated factors, such as demographic characteristics, SES, and physical and psychological function. The FM patients were assessed using the following self-reported questionnaires: the Medical Outcomes Study Short-Form Health Survey, the Fibromyalgia Impact Questionnaire, the Brief Fatigue Inventory, the Beck Depression Inventory, the State-Trait Anxiety Inventory, the Self-Efficacy Scale, and the Social Support Scale. RESULTS: Of the 343 patients, 76 (22.1%) were obese; these patients did not differ from the non-obese patients in terms of tender points or self-reported questionnaire scores. FM patients with lower SES - as indexed by unemployment, lower income, and education levels - had more severe symptoms, and poorer QoL and function compared to those with higher SES. CONCLUSIONS: In contrast to Western patients, symptom severity in Korean FM patients is associated with SES, but not with obesity.

Effect of Recombinant Human Bone Morphogenetic Protein-2 and Adipose Tissue-Derived Stem Cell on New Bone Formation in High-Speed Distraction Osteogenesis.

PURPOSE: The effects of recombinant human bone morphogenetic protein-2 (rhBMP-2) and osteogenically differentiated adipose tissue-derived stem cells (ADSC) on new bone formation in high-speed distraction osteogenesis of adult rabbit cranium were investigated. MATERIALS AND METHODS: A total of 41 adult rabbits were used in the study. Distraction began after a 5-day latency period at a rate of 1.5 mm twice a day until 10-mm length gain was obtained both in the control group, where a bone defect was induced, and in the experimental group, in which ADSC (group A), rhBMP-2 (group B), or both (group C) were injected in the distraction gap after distraction. At 4, 8, and 12 weeks after distraction, computed tomography analysis was done to determine the bone defect dimension and bone mineral density (BMD), while histologic examination was also done to calculate bone formation ratio. RESULTS: Bone defect dimension significantly decreased in groups B and C, compared with the control group, at 4 and 12 weeks after distraction. BMD was significantly increased in groups B and C at 4 weeks. On histologic examination, bone formation ratio was significantly increased in group C only at 12 weeks. CONCLUSION: This study suggests that the use of rhBMP-2 in combination with or without ADSC is helpful to promote bone regeneration in high-speed distraction osteogenesi s of adult rabbit cranium.

Internal carotid artery agenesis associated with a rare collateral pathway: supraclinoid-supraclinoid anastomosis. A case report.

Internal carotid artery (ICA) agenesis is an infrequent vascular anomaly, less than 0.01% of the population. Here we report a case of internal carotid agenesis with a rare collateral pathway, via supraclinoid ICA anastomosis to the contralateral supraclinoid ICA.

The AtLRK10L1.2, Arabidopsis ortholog of wheat LRK10, is involved in ABA-mediated signaling and drought resistance.

KEY MESSAGE: The loss-of-function mutants of the Arabidopsis orthologue of the wheat LRK10 gene shows ABA-insensitive and drought stress-sensitive phenotypes, suggesting that LRK10L1.2 is positively involved in ABA signaling. A subset of receptor-like kinases (RLKs) superfamily proteins play a key role in sensing internal and external signals. A gene encoding Arabidopsis thaliana Leaf rust 10 disease-resistance locus receptor-like protein kinase 1 (AtLRK10L1), most closely related to wheat LRK10, expresses two different transcripts, LRK10L1.1 and LRK10L1.2, using alternative promoters. The T-DNA insertion mutant, lrk10l1-2, that specifically shuts down LRK10L1.2 transcription displayed an abscisic acid (ABA)-insensitive phenotype in seed germination and seedling growth. However, the lrk10l1.2 mutant exhibited reduced tolerance to drought stress, compared with wild type, which is accompanied by alteration of stomatal apertures. The transgenic plants overexpressing full-length LRK10L1.2, which localizes to the plasma membrane (PM) complemented the phenotypes of lrk10l1-2 mutant background, while those expressing LRK10L1.2 Nu1, which switched its localization to the endoplasmic reticulum (ER) by skipping of a mini-exon, showed even higher ABA insensitivity and drought sensitivity than its mutant background. Our results suggest that ABA signaling involves the PM-localized LRK10L1.2.

Alternative splicing of mini-exons in the Arabidopsis leaf rust receptor-like kinase LRK10 genes affects subcellular localisation.

KEY MESSAGE: AtLRK10L1.2 produces a variety of alternatively spliced variants in the region a mini-exon and skipping of the mini-exon alters the subcellular localization of the protein. We have examined expression and alternative splicing in the gene encoding Arabidopsis LRK10-like 1 (AtLRK10L1) which is most closely related to wheat leaf rust 10 disease-resistance locus receptor-like protein kinase (LRK10). AtLRK10L1 produces two different transcripts, LRK10L1.1 and 1.2 through the use of two different promoters. We found no evidence of alternative splicing for the AtLRK10L1.1 transcript but identified numerous alternative splicing variants of AtLRK10L1.2 by sequencing of cloned cDNAs prepared from RNA isolated from whole cell, nucleolar and nucleoplasmic fractions. Many of these transcripts contained unspliced introns and accumulated differentially in the nucleolus and the nucleoplasm consistent with intron retention transcripts being retained in the nucleus (Göhring et al., Plant Cell 26:754-764, 2014). We examined the fate of different alternatively spliced transcripts by fusing variants to YFP and expressing them by agroinfiltration in Nicotiana benthamiana. AtLRK10L1 contains a 45 nt mini-exon which encodes part of a putative transmembrane domain. Full-length cDNA of LRK10L1.2 fused to YFP targeted the fusion protein to the plasma membrane while expression of transcripts where the mini-exon had been deleted, altered the localization of the fusion protein to the endoplasmic reticulum. Similarly, expression of full-length and mini-exon deleted versions of three other members of the LRK10 receptor-like kinase (RLK) gene family also showed the switch in localization. Thus, the mini-exons in Arabidopsis LRK10 genes are required for localization to the plasma membrane.

Rheumatoid arthritis patients fulfilling Korean National Health Insurance reimbursement guidelines for anti-tumor necrosis factor-α treatment and comparison to other guidelines.

The aim of this study was to compare anti-tumor necrosis factor-α (TNFα) treatment status in rheumatoid arthritis (RA) patients with the Korean National Health Insurance (KNHI) reimbursement eligibility criteria and with American College of Rheumatology (ACR) recommendations, Japan College of Rheumatology (JCR) guidelines and British Society for Rheumatology (BSR) guidelines. Between December 2011 and August 2012, outpatients from 17 South Korean general hospitals diagnosed with RA according to the 1987 ACR criteria were enrolled into a noninterventional, cross-sectional, observational study. Of 1700 patients (1414 female (83.2 %), mean age of 56.6 ± 12.0, mean disease duration 97.9 ± 91.8 months), 306 (18.0 %) had used anti-TNFα agents, and 224 (13.2 %) were currently using an anti-TNFα agent. Of 1394 anti-TNFα-naive patients, 32 (2.3 %) met KNHI reimbursement guidelines, 148 (10.6 %) met ACR recommendations, and 127 (9.1 %) and 126 (9.0 %) were considered eligible for anti-TNFα agents according to JCR and BSR guidelines, respectively. The main discrepancy was the higher active joint count required by the KNHI eligibility criteria. In the opinion of treating rheumatologists, the KNHI reimbursement criteria ineligibility accounted for 15.3 % (n = 213) of the reasons for not initiating anti-TNFα agents in anti-TNFα-naive group. The anti-TNFα user group showed significantly higher disease activity than the anti-TNFα-naive group based on DAS28 score. In comparison with the ACR recommendations and JCR and BSR guidelines, fewer patients met KNHI reimbursement eligibility criteria for anti-TNFα agents. The current amendment of the KNHI criteria based on DAS28 score will improve an access to biologic agents including anti-TNFα treatment for South Korean patients with active RA.

MRI molecular imaging using GLUT1 antibody-Fe3O4 nanoparticles in the hemangioma animal model for differentiating infantile hemangioma from vascular malformation.

The purpose of this study is to evaluate the efficacy of glucose transporter protein 1 (GLUT1) antibody-conjugated iron oxide nanoparticles (Fe3O4 NPs) as magnetic resonance imaging (MRI) molecular imaging agents for differentiating infantile hemangioma from vascular malformation in the hemangioma animal model. The conjugation of Fe3O4 NPs with anti-GLUT1 antibodies leads to a significantly increased uptake of NPs by human umbilical vein endothelial cells. MRI imaging following the intravenous injection of GLUT1 antibody-Fe3O4 NPs yielded a significantly lower signal intensity than did unconjugated Fe3O4 NPs. Upon histological examination of the GLUT1 antibody-Fe3O4 NPs, Prussian blue-stained NPs were identified in CD31-positive endothelial cells of hemangioma. In contrast, when treated with unconjugated Fe3O4 NPs, Prussian blue-stained NPs were found in macrophages rather than in endothelial cells. GLUT1 antibody conjugation can effectively target the injected Fe3O4 NPs to GLUT1-positive tumor cells in infantile hemangioma.

Infliximab partially alleviates the bite force reduction in a mouse model of temporomandibular joint pain.

Temporomandibular joint (TMJ) disorder is clinically important because of its prevalence, chronicity, and therapy-refractoriness of the pain. In this study, we investigated the effect of infliximab in a mouse model of TMJ pain using a specially-engineered transducer for evaluating the changes in bite force (BF). The mice were randomly divided into three groups (7 mice per group): the control group, the complete Freund's adjuvant (CFA) group, and the infliximab group. BF was measured at day 0 (baseline BF). After measuring the baseline BF, CFA or incomplete Freund's adjuvant was injected into both TMJs and then the changes in BF were measured at days 1, 3, 5, 7, 9, and 13 after the TMJ injection. For measuring the BF, we used a custom-built BF transducer. Control, CFA, and infliximab groups showed similar baseline BF at day 0. From day 1, a significant reduction in BF was observed in the CFA group, and this reduction in BF was statistically significant compared to that in the control group (P < 0.05). This reduction in BF was maintained until day 7, and BF started to recover gradually from day 9. In the infliximab group also, the reduction in BF was observed on day 1, and this reduction was maintained until day 7. However, the degree of reduction in BF was less remarkable compared to that in the CFA group. The reduction in BF caused by injection of CFA into the TMJ could be partially alleviated by the injection of anti-tumor necrosis factor alpha, infliximab.

Phytaspase, a relocalisable cell death promoting plant protease with caspase specificity.

Caspases are cysteine-dependent proteases and are important components of animal apoptosis. They introduce specific breaks after aspartate residues in a number of cellular proteins mediating programmed cell death (PCD). Plants encode only distant homologues of caspases, the metacaspases that are involved in PCD, but do not possess caspase-specific proteolytic activity. Nevertheless, plants do display caspase-like activities indicating that enzymes structurally distinct from classical caspases may operate as caspase-like proteases. Here, we report the identification and characterisation of a novel PCD-related subtilisin-like protease from tobacco and rice named phytaspase (plant aspartate-specific protease) that possesses caspase specificity distinct from that of other known caspase-like proteases. We provide evidence that phytaspase is synthesised as a proenzyme, which is autocatalytically processed to generate the mature enzyme. Overexpression and silencing of the phytaspase gene showed that phytaspase is essential for PCD-related responses to tobacco mosaic virus and abiotic stresses. Phytaspase is constitutively secreted into the apoplast before PCD, but unexpectedly is re-imported into the cell during PCD providing insights into how phytaspase operates.

Effect of recombinant human bone morphogenetic protein-2 and osteoprotegerin-Fc in MC3T3-E1 cells.

Objective: We compared the osteoblastogenesis by serially administrating recombinant human bone morphogenetic protein-2 (rhBMP-2) and osteoprotegerin-immunoglobulin Fc segment complex (OPG-Fc). Methods: The MC3T3-E1 preosteoblast cell line was differentiated for 1, 3, and 7 days with a treatment of OPG-Fc in 10~200 ng/mL concentration and the cell viability was evaluated by Cell Counting Kit-8 analysis. The level of differentiation from MC3T3-E1 cells to osteoblasts was determined by alkaline phosphatase activity. The level of runt domain-containing transcription factor 2 (Runx2) and osteopontin (OPN) manifestation, involved in osteoblast differentiation, was examined by real-time polymerase chain reaction and western blotting. Results: During MC3T3-E1 cell differentiation, the differentiation level was high with 1-day treatment using 100 ng/mL OPG-Fc. The treatment with 50 ng/mL rhBMP-2 for 7 days, followed by 1-day treatment with 100 ng/mL OPG-Fc produced the highest differentiation level, which was approximately 5.3 times that of the control group (p<0.05). The expression of Runx2 mRNA significantly increased, reaching 2.5 times the level of the control group under the condition of 7-day treatment with rhBMP-2 and 1-day treatment with OPG-Fc (p<0.001). The expression of Runx2 protein significantly increased to approximately 5.7 times that of the control group under the condition of 7-day treatment with rhBMP-2, followed by 1-day treatment with OPG-Fc (p<0.01). The expression of OPN protein showed no change from that of the control group under various conditions of rhBMP-2 and OPG-Fc combinations. Conclusion: These results imply that the treating preosteoblasts with rhBMP-2 first and then with OPG-Fc increased osteoblast differentiation efficacy.