Mast cell-derived prostaglandin D2 limits the subcutaneous absorption of honey bee venom in mice.

Mast cells play pivotal roles in innate host defenses against venom. Activated mast cells release large amounts of prostaglandin D2 (PGD2). However, the role of PGD2 in such host defense remains unclear. We found that c-kit-dependent and c-kit-independent mast cell-specific hematopoietic prostaglandin D synthase (H-pgds) deficiency significantly exacerbated honey bee venom (BV)-induced hypothermia and increased mortality rates in mice. BV absorption via postcapillary venules in the skin was accelerated upon endothelial barrier disruption resulting in increased plasma venom concentrations. These results suggest that mast cell-derived PGD2 may enhance host defense against BV and save lives by inhibiting BV absorption into circulation.

Gas-Phase Structures of [Au21(SR)14]- and [Au17(SR)10]- with Eight Electrons: Can They Support an Icosahedral Au13 Core?

A prototypical thiolate (RS)-protected gold cluster [Au25(SR)18]- has high stability due to specific geometric and electronic structures: an icosahedral (Ih) Au13 core with a closed electronic shell containing eight electrons is completely protected by six units of Au2(SR)3. Nevertheless, collisional excitation of [Au25(SR)18]- in a vacuum induces the sequential release of Au4(SR)4 to form [Au21(SR)14]- and [Au17(SR)10]- both containing eight electrons. To answer a naive question of whether these fragments bear an Ih Au13(8e) core, the geometrical structures of [Au21(SC3H7)14]- and [Au17(SC3H7)10]- in the gas phase were examined by the combination of anion photoelectron spectroscopy and density functional theory (DFT) calculation of simplified models of [Au21(SCH3)14]- and [Au17(SCH3)10]-. We concluded that [Au21(SC3H7)14]- retains a slightly distorted Ih Au13(8e) core, while [Au17(SC3H7)10]- has an amorphous Au13 core composed of triangular Au3, tetrahedral Au4, and prolate Au7 units. DFT calculations on putative species [Au19(SCH3)12]- and [Au18(SCH3)11]- suggested that the Ih Au13(8e) core undergoes dramatic structural deformation due to mechanical stress from µ2 ligation of only one RS.

Plasma prolactin axis shift from placental to pituitary origin in late prepartum mice.

The placenta secretes a prolactin (PRL)-like hormone PRL3B1 (placental lactogen II), a luteotropic hormone essential for maintaining pregnancy until labor in mice. A report from 1984 examined the secretion pattern of PRL3B1 in prepartum mice. In the current study, we found contradictory findings in the secretion pattern that invalidate the previous report. By measuring maternal plasma PRL3B1 and PRL every 4 hrs from gestational day 17 (G17), we newly discovered that maternal plasma PRL3B1 levels decrease rapidly in prepartum C57BL/6 mice. Interestingly, the onset of this decline coincided with the PRL surge at G18, demonstrating a plasma prolactin axis shift from placental to pituitary origin. We also found that maternal plasma progesterone regression precedes the onset of the PRL shift. The level of Prl3b1 mRNA was determined by RT-qPCR in the placenta and remained stable until parturition, implying that PRL3B1 peptide production or secretion was suppressed. We hypothesized that production of the PRL family, the 25 paralogous PRL proteins exclusively expressed in mice placenta, would decrease alongside PRL3B1 during this period. To investigate this hypothesis and to seek proteomic changes, we performed a shotgun proteome analysis of the placental tissue using data-independent acquisition mass spectrometry (DIA-MS). Up to 5,891 proteins were identified, including 17 PRL family members. Relative quantitative analysis between embryonic day 17 (E17) and E18 placentas showed no significant difference in the expression of PRL3B1 and most PRL family members except PRL7C1. These results suggest that PRL3B1 secretion from the placenta is suppressed at G18 (E18).

17ß-Estradiol (E2) Activates Matrix Mineralization through Genomic/Nongenomic Pathways in MC3T3-E1 Cells.

Estrogen plays an important role in osteoporosis prevention. We herein report the possible novel signaling pathway of 17ß-estradiol (E2) in the matrix mineralization of MC3T3-E1, an osteoblast-like cell line. In the culture media-containing stripped serum, in which small lipophilic molecules such as steroid hormones including E2 were depleted, matrix mineralization was significantly reduced. However, the E2 treatment induced this. The E2 effects were suppressed by ICI182,780, the estrogen receptor (ER)α, and the ERß antagonist, as well as their mRNA knockdown, whereas Raloxifene, an inhibitor of estrogen-induced transcription, and G15, a G-protein-coupled estrogen receptor (GPER) 1 inhibitor, had little or no effect. Furthermore, the E2-activated matrix mineralization was disrupted by PMA, a PKC activator, and SB202190, a p38 MAPK inhibitor, but not by wortmannin, a PI3K inhibitor. Matrix mineralization was also induced by the culture media from the E2-stimulated cell culture. This effect was hindered by PMA or heat treatment, but not by SB202190. These results indicate that E2 activates the p38 MAPK pathway via ERs independently from actions in the nucleus. Such activation may cause the secretion of certain signaling molecule(s), which inhibit the PKC pathway. Our study provides a novel pathway of E2 action that could be a therapeutic target to activate matrix mineralization under various diseases, including osteoporosis.

Amide-Ligand-Promoted Silver-Catalyzed C-H Fluorination via Radical/Polar Crossover.

We describe an efficient method for benzylic C-H fluorination via sequential hydrogen-atom transfer (HAT) and oxidative radical-polar crossover utilizing the Ag(I)/Selectfluor system. Amide ligands, such as benzamide and sulfonamide, substantially facilitate the processes leading to a carbocation intermediate, which subsequently reacts with nucleophilic fluorinating reagent to form a C-F bond. This protocol is applicable to the fluorination of all 1°, 2°, and 3° C-H bonds as well as to late-stage C-H fluorination of bioactive molecules.

Effects of Perfluorooctane Sulfonate on Cerebellar Cells via Inhibition of Type 2 Iodothyronine Deiodinase Activity.

Perfluorooctane sulfonate (PFOS) has been used in a wide variety of industrial and commercial products. The adverse effects of PFOS on the developing brain are becoming of a great concern. However, the molecular mechanisms of PFOS on brain development have not yet been clarified. We investigated the effect of early-life exposure to PFOS on brain development and the mechanism involved. We investigated the change in thyroid hormone (TH)-induced dendrite arborization of Purkinje cells in the primary culture of newborn rat cerebellum. We further examined the mechanism of PFOS on TH signaling by reporter gene assay, quantitative RT-PCR, and type 2 iodothyronine deiodinase (D2) assay. As low as 10-7 M PFOS suppressed thyroxine (T4)-, but not triiodothyronine (T3)-induced dendrite arborization of Purkinje cells. Reporter gene assay showed that PFOS did not affect TRα1- and TRß1-mediated transcription in CV-1 cells. RT-PCR showed that PFOS suppressed D2 mRNA expression in the absence of T4 in primary cerebellar cells. D2 activity was also suppressed by PFOS in C6 glioma-derived cells. These results indicate that early-life exposure of PFOS disrupts TH-mediated cerebellar development possibly through the disruption of D2 activity and/or mRNA expression, which may cause cerebellar dysfunction.

PGD2 /CRTH2 signaling promotes acquired immunity against bee venom by enhancing IgE production.

IgE-dependent/independent activation of mast cell (MC) has been assumed to play a host defensive role against venom injection in skin. However, its detailed mechanisms remain unknown. We aimed to investigate the contribution of MC-derived prostaglandin D2 (PGD2 )-mediated signaling in host defense against bee venom (BV). To achieve this, we utilized gene-deficient mice of a PGD2 receptor, chemoattractant receptor-homologous molecule expressed on Th2 cells (CRTH2). We first confirmed that subcutaneous injection of BV produced PGD2 equally in wild-type (WT) and CRTH2-deficient (Crth2-/- ) mice skins. The BV injection dropped body temperature and impaired kidney equally in both lines of mice. In WT mice, pre-injection of BV (3 weeks) significantly inhibited the hypothermia and kidney impairment caused by second BV injection. In contrast, this pre-injection was not effective for the second BV injection in Crth2-/- mice. We also found that BV injections increased serum BV-specific IgE levels in WT mice, and its serum transfused mice improved the BV-induced hypothermia in naïve WT mice. In contrast, serum BV-specific IgE level was significantly lower in Crth2-/- mice. FACS analysis showed the BV injection stimulate migration of dendritic cells (DCs) into regional lymph nodes in WT mice. In Crth2-/- mice, its number was significantly smaller than that of WT mice. In conclusion, PGD2 /CRTH2 signaling plays defensive role against second BV injection. This signaling promotes BV-specific IgE production at least partially by promoting DCs migration into regional lymph node.

The effectiveness of adjuvant chemotherapy for Stage I pancreatic cancer based on the UICC 8th edition.

BACKGROUND: Adjuvant chemotherapy is recommended for patients with pancreatic cancer after curative resection. However, there is limited evidence regarding the efficacy and prognostic factors for adjuvant chemotherapy in patients with stage I pancreatic cancer. This study aimed to identify patients in whom chemotherapy was effective and to detect prognostic factors for stage I pancreatic cancer based on guidelines of the 8th edition of the Union for International Cancer Control (UICC). METHODS: Between 2009 and 2017, 108 patients diagnosed with stage I pancreatic cancer were enrolled in this study. They were distributed into invasion (n = 68) and non-invasion (n = 40) groups. The relationship between clinicopathological variables, including various prognostic factors, disease-free survival (DFS), and overall survival (OS), were investigated by univariate and multivariate analyses. RESULTS: Five-year survival in all patients with stage I pancreatic cancer was 38.9%. Adjuvant chemotherapy failed to improve DFS or OS in patients with stage I cancer (DFS, p = 0.26; OS, p = 0.30). In subgroup analysis, adjuvant chemotherapy significantly improved DFS (multivariate-adjusted hazard ratio (HR), 0.40; 95% confidence interval [CI], 0.21-0.78; p = 0.007) and OS (multivariate-adjusted HR, 0.32; 95% CI, 0.15-0.68; p = 0.003) in the invasion group than in non-invasion group. In contrast, in the non-invasion group, adjuvant chemotherapy failed to improve DFS and OS in univariate analysis (DFS, p = 0.992; OS, p = 0.808). CONCLUSION: For stage I pancreatic cancer, based on guidelines of the UICC 8th edition, adjuvant chemotherapy may benefit patients with extrapancreatic invasion.

Atrogin-1 knockdown inhibits the autophagy-lysosome system in mammalian and avian myotubes.

Atrogin-1 plays an important role in ubiquitin-proteasome proteolysis in vertebrate skeletal muscles. Recently, atrogin-1 has been shown to be involved in the autophagy-lysosome system, another proteolytic system, in the murine and fish hearts and skeletal muscles. With the aim to elucidate the effect of atrogin-1 on the autophagy-lysosome system in mammalian and avian skeletal muscles, this study has examined the effects of atrogin-1 knockdown on autophagy-lysosome-related proteins in C2C12 and chicken embryonic myotubes. Using the levels of microtubule-associated protein light chain 3 (LC3)-II protein, it was confirmed that atrogin-1 knockdown blocked the autophagic flux in both the myotubes. In addition, atrogin-1 knockdown in C2C12 myotubes significantly decreased the level of autophagy-related gene (ATG)12-ATG5 conjugate, which is supposedly necessary for the fusion of autophagosomes and lysosomes. Atrogin-1 knockdown also resulted in downregulation of forkhead box O3, a transcription factor for ATG12. These data suggest that atrogin-1 is essential for the normal autophagy-lysosome system in the striated muscles of vertebrates.

Histone Deacetylase 3 Inhibitor Alleviates Cerebellar Defects in Perinatal Hypothyroid Mice by Stimulating Histone Acetylation and Transcription at Thyroid Hormone-Responsive Gene Loci.

Perinatal hypothyroidism impairs cerebellar organogenesis and results in motor coordination defects. The thyroid hormone receptor binds to corepressor complexes containing histone deacetylase (HDAC) 3 in the absence of ligands and acts as a transcriptional repressor. Although histone acetylation status is strongly correlated with transcriptional regulation, its role in cerebellar development remains largely unknown. We aimed to study whether the cerebellar developmental defects induced by perinatal hypothyroidism can be rescued by treatment with a specific HDAC3 inhibitor, RGFP966. Motor coordination was analyzed using three behavioral tests. The cerebella were subjected to RT-qPCR and chromatin immunoprecipitation assays for acetylated histone H3. The treatment with RGFP966 partially reversed the cerebellar morphological defects in perinatal hypothyroid mice. These findings were associated with the alleviation of motor coordination defects in these mice. In addition, the RGFP966 administration increased the mRNA levels of cerebellar thyroid hormone-responsive genes. These increases were accompanied by augmented histone acetylation status at these gene loci. These findings indicate that HDAC3 plays an important role in the cerebellar developmental defects induced by perinatal hypothyroidism. The HDAC3 inhibitor might serve as a novel therapeutic agent for hypothyroidism-induced cerebellar defects by acetylating histone tails and stimulating transcription at thyroid hormone-responsive gene loci.

[Cunninghamella bertholletiae-infective endocarditis complicated by tricuspid valve giant vegetation in a patient with aplastic anemia].

A 62-year-old female was presented to the hospital of the current study for pancytopenia and was diagnosed with severe aplastic anemia. She was treated with a combination therapy of antithymocyte globulin, cyclosporine A, and eltrombopag. The patient also presented with febrile neutropenia after commencement of the treatment and did not respond to the various antibiotics and antifungal agents. Echocardiography showed a giant vegetation attached to the tricuspid valve on Day 78 of the immunosuppressive therapy, and the tricuspid valve replacement was performed. The vegetation was formed by Cunninghamella bertholletiae, a mucor type, and was treated with high-dose liposomal amphotericin B (L-AMB), which was terminated after six weeks due to decreased renal function. In addition, mucormycosis was controlled by posttreatment with posaconazole (PSCZ). This is a rare case of mucormycosis that developed into a giant vegetation during the immunosuppressive therapy for aplastic anemia. It was believed to be a valuable case to consider in future mucormycosis treatment, including the success of the treatment by switching from L-AMB to PSCZ.

Hepatic thermal injury promotes colorectal cancer engraftment in C57/black 6 mice.

Treatment options for liver metastases (primarily colorectal cancer) are limited by high recurrence rates and persistent tumor progression. Surgical approaches to management of these metastases typically use heat energy including electrocautery, argon beam coagulation, thermal ablation of surgical margins for hemostasis, and preemptive thermal ablation to prevent bleeding or to effect tumor destruction. Based on high rates of local recurrence, these studies assess whether local effects of hepatic thermal injury (HTI) might contribute to poor outcomes by promoting a hepatic microenvironment favorable for tumor engraftment or progression due to induction of procancer cytokines and deleterious immune infiltrates at the site of thermal injury. To test this hypothesis, an immunocompetent mouse model was developed wherein HTI was combined with concomitant intrasplenic injection of cells from a well-characterized MC38 colon carcinoma cell line. In this model, HTI resulted in a significant increase in engraftment and progression of MC38 tumors at the site of thermal injury. Furthermore, there were local increases in expression of messenger ribonucleic acid (mRNA) for hypoxia-inducible factor-1α (HIF1α), arginase-1, and vascular endothelial growth factor α and activation changes in recruited macrophages at the HTI site but not in untreated liver tissue. Inhibition of HIF1α following HTI significantly reduced discreet hepatic tumor development (P = 0.03). Taken together, these findings demonstrate that HTI creates a favorable local environment that is associated with protumorigenic activation of macrophages and implantation of circulating tumors. Discrete targeting of HIF1α signaling or inhibiting macrophages offers potential strategies for improving the outcome of surgical management of hepatic metastases where HTI is used.

The Prognostic Significance of C-reactive Protein-To-Lymphocyte Ratio in Colorectal Liver Metastases.

BACKGROUND: The preoperative systemic inflammation has been reported to predict tumor recurrence and survival in various cancers, including colorectal liver metastases (CRLM). However, more sensitive biomarker is required to improve perioperative management of CRLM. Therefore, we developed a novel indicator; C-reactive protein-to-lymphocyte ratio (CLR). The aim of this study is to evaluate the prognostic significance of CLR in patients with CRLM after hepatic resection. MATERIALS AND METHODS: The study comprised 197 patients who had undergone hepatic resection for CRLM between January 2000 and December 2018. We retrospectively investigated the relation between CLR and disease-free survival and overall survival after hepatic resection and compared their prognostic significance with that of the C-reactive protein-to-albumin ratio and neutrophil-to-lymphocyte ratio. RESULTS: Optimal cutoff level of the CLR by receiver operating characteristics analysis was 62.8 × 10-6. By multivariate analysis, CLR was an independent predictor of disease-free survival [hazard ratio (HR): 1.463, 95% confidence interval (CI): 1.003-2.135, P = 0.048), whereas lymph node metastases>4 (HR: 1.804, 95% CI: 1.100-2.958, P = 0.019) and CLR (HR: 1.656, 95% CI: 1.007-2.724, P = 0.047) were independent predictors of overall survival, while the C-reactive protein-to-albumin ratio and neutrophil-to-lymphocyte ratio were not. CONCLUSIONS: CLR may be an independent and significant indicator of poor long-term outcomes in patients with CRLM after hepatic resection.

Preoperative controlling nutritional status (CONUT) score predicts long-term outcomes in patients with non-B non-C hepatocellular carcinoma after curative hepatic resection.

PURPOSE: The controlling nutritional status (CONUT) score has been reported to predict outcomes in patients with hepatocellular carcinoma (HCC). However, the prognostic significance of the CONUT score in patients with non-B non-C (NBNC) HCC remains to be established. METHODS: The study comprised 246 patients who had undergone elective hepatic resection for HCC between April 2003 and October 2017. We retrospectively investigated the relation between preoperative CONUT score as well as clinicopathological characteristics and disease-free survival (DFS) as well as overall survival (OS). RESULTS: In univariate analyses, CONUT score was associated with DFS and OS in patients with NBNC-HCC (p ≤ 0.01), while there was no significant association of CONUT score with DFS and OS in patients with HBV- and HCV-related HCC (p ≥ 0.1). Of the 111 patients with NBNC-HCC, 97 (87.4%) had CONUT score ≤ 3 (low CONUT score) and the other 14 (12.6%) had CONUT score ≥ 4 (high CONUT score). In the patients with NBNC-HCC, multivariate analysis identified age ≥ 65 years (p = 0.03), multiple tumors (p < 0.01), and high CONUT score (p = 0.03) as the independent and significant predictors of DFS, while multiple tumors (p = 0.01), microvascular invasion (p < 0.01), and high CONUT score (p = 0.01) were the independent and significant predictors of OS. CONCLUSIONS: The CONUT score seems to be a reliable and independent predictor of both DFS and OS after hepatic resection for NBNC-HCC.

[Successful treatment with blinatumomab for refractory B lymphoblastic leukemia complicated with malignant pleural effusion].

A 77-year-old man diagnosed with mixed-phenotype acute leukemia (MPAL (B/Myeloid), NOS) achieved complete remission (CR) after eight courses of hyper-CVAD/MA therapy. However, 6 months later, blasts were observed on peripheral blood smear, and bone marrow aspiration revealed that the disease had relapsed as B lymphoblastic leukemia (ALL). At this time, he had left pleural effusion. He received two courses of inotuzumab ozogamicin (InO) and achieved second hematological CR, but the left pleural effusion worsened over time, suggesting poor disease control. After changing the regimen to blinatumomab, aspiration biopsy cytology showed that the blasts in the pleural fluid disappeared and respiratory distress improved after one course of treatment. Flow cytometry results showed increased populations of CD3-positive T-cells, suggesting that blinatumomab may have migrated into the pleural fluid and exerted an antitumor effect. Although new ALL-specific antibody drugs, such as InO and blinatumomab, are expected to improve prognosis, only few reports have described their tissue migration. The difference between InO and blinatumomab in terms of efficacy of treating malignant pleural effusion remains unclear and should be explored in additional cases.

Pancreatic cancer treatment: better, but a long way to go.

Remarkable progress has been made in treating pancreatic cancer over the past century, including refinement of our surgical techniques and improvements in adjuvant and neoadjuvant therapies. Despite these advances, the incidence of pancreatic cancer is rising globally, and it remains a deadly disease. In this review, we highlight the historical perspectives of pancreatic cancer treatment and outline the areas of future advancement that will assist progression towards better outcomes. Areas of future advancement include improving prevention strategies and early detection, refining our molecular understanding of pancreatic cancer, identifying more effective systemic therapies, and improving quality of life and surgical outcomes. Furthermore, systems need to be put in place to ensure all patients with pancreatic cancer receive high quality care and are given the appropriate options and sequence of therapy. This is best achieved through multidisciplinary care.

The Comparison of Inflammation-Based Prognostic Scores in Patients With Extrahepatic Bile Duct Cancer After Pancreaticoduodenectomy.

BACKGROUND: Inflammation-based prognostic scores are associated with tumor recurrence and survival in various cancers. The aim of this study was to identify the significance of inflammation-based prognostic scores and to detect the most useful score in patients with distal extrahepatic bile duct cancer after pancreaticoduodenectomy. METHODS: Between 2000 and 2015, 121 patients were enrolled in this retrospective study. The relationship between clinicopathological variables including various prognostic scores and disease-free (DFS) as well as overall (OS) survival was investigated by univariate analysis. The area under the receiver operating characteristics curve was calculated to compare the predictive ability of each scoring system. Multivariate analysis was performed to identify the clinicopathological variables associated. RESULTS: In univariate analysis, Glasgow prognostic score (GPS), mGPS, C-reactive protein/Alb ratio score, prognostic index, and preoperative monocyte count were significant risk factors for both DFS and OS. The area under the receiver operating characteristics curve of GPS is consistently larger in comparison with other four scores in both DFS as well as OS. In multivariate analysis, GPS was an independent risk factor of both tumor recurrence and poor prognosis. CONCLUSIONS: GPS score is an independent tumor recurrence and prognostic factor in patients with distal extrahepatic bile duct cancer and is superior to the other prognostic scores.

Salvage Haploidentical Transplantation Using Low-dose ATG for Early Disease Relapse after First Allogeneic Transplantation: A Retrospective Single-center Review.

Second allogeneic stem cell transplantation (allo-SCT) is a potentially curative therapy for patients who relapse after first allo-SCT. Human leukocyte antigen (HLA)-haploidentical related donors provide the broad opportunity to conduct second SCT at the appropriate time, but the efficacy of second SCT from haploidentical donors after relapse has not been established. We retrospectively analyzed the records of 33 patients who underwent second SCT. Twenty patients underwent haplo-SCT with low-dose antithymocyte globulin (ATG), and the other 13 patients underwent conventional- SCTs, including HLA-matched related peripheral blood, unrelated bone marrow or cord blood. Three years after the second SCT, the overall survival (OS) and progression-free survival (PFS) of all patients were 32.5% and 23.9%. Multivariate analyses indicated that non-complete response at second SCT, less than 1-year interval to relapse after first- SCT, and total score ≥ 3 on the hematopoietic cell transplantation-specific comorbidity index were significantly associated with a lower PFS rate. The haplo- and conventional- SCT groups showed equivalent results regarding OS, PFS, cumulative incidences of relapse, non-relapse mortality and graft-versus-host disease. The neutropenic period after transplantation was significantly shorter in haplo- SCT than conventional- SCT (10.5 days vs. 16 days, p=0.001). Our analysis revealed that haplo-SCT could be an alternative therapeutic option for relapsed patients after first SCT.

Reducing the Cytotoxicity of Lipid Nanoparticles Associated with a Fusogenic Cationic Lipid in a Natural Killer Cell Line by Introducing a Polycation-Based siRNA Core.

Introducing siRNA into human immune cells by an artificial delivery system continues to be a challenging issue. We previously developed a multifunctional envelope-type nanodevice (MEND) containing the YSK12-C4, a fusogenic cationic lipid, (YSK12-MEND) and succeeded in the efficient delivery of siRNA into human immune cell lines. Significant cytotoxicity, however, was observed at siRNA doses needed for gene silencing in NK-92 cells. NK-92 cells, a unique natural killer (NK) cell line, would be applicable for use in clinical NK therapy. Thus, reducing the cytotoxicity of the YSK12-MEND in NK-92 cells would strengthen the efficacy of NK-92 cell-based therapy. The amount of the YSK12-C4 in the MEND needed to be reduced to reduce the cytotoxicity, because the cytotoxicity was directly associated with the YSK12-C4. In the present study, we decreased the total amount of lipid, including the YSK12-C4, by introducing a core formed by electrostatic interactions of siRNA with a polycation (protamine) (siRNA core), which led to a decrease in cytotoxicity in NK-92 cells. We prepared a YSK12-MEND containing an siRNA core (YSK12-MEND/core) at charge ratios (CR: YSK12-C4/siRNA) of 10, 5, 3, and 2.5 and compared the YSK12-MEND/core with that for a YSK12-MEND (CR16.9). Cell viability was increased by more than 2 times at a CR5 or less. On the other hand, the YSK12-MEND/core (CR5) maintained the same gene silencing efficiency (60%) as the YSK12-MEND. Interestingly, the cellular uptake efficiency and hemolytic activity of the YSK12-MEND/core (CR5) was reduced compared to that for the YSK12-MEND. In calculating the silencing activity per cellular uptake efficiency and hemolytic activity, the value for the YSK12-MEND/core (CR5) was more than 2 times as high as that of the YSK12-MEND. The fact indicates that after endosomal escape, the process can be enhanced by using a YSK12-MEND/core (CR5). Thus, introducing an siRNA core into lipid nanoparticles can be a potent strategy for decreasing cytotoxicity without an appreciable loss of gene silencing activity in NK-92 cells.