Generation of canine induced pluripotent stem cells under feeder-free conditions using Sendai virus vector encoding six canine reprogramming factors

Although it is in its early stages, canine induced pluripotent stem cells (ciPSCs) hold great potential for innovative translational research in regenerative medicine, developmental biology, drug screening, and disease modeling. However, almost all ciPSCs were generated from fibroblasts, and available canine cell sources for reprogramming are still limited. Furthermore, no report is available to generate ciPSCs under feeder-free conditions because of their low reprogramming efficiency. Here, we reanalyzed canine pluripotency-associated genes and designed canine LIN28A, NANOG, OCT3/4, SOX2, KLF4, and C-MYC encoding Sendai virus vector, called 159cf. and 162cf. We demonstrated that not only canine fibroblasts but also canine urine-derived cells, which can be isolated using a noninvasive and straightforward method, were successfully reprogrammed with or without feeder cells. ciPSCs existed in undifferentiated states, differentiating into the three germ layers in vitro and in vivo. We successfully generated ciPSCs under feeder-free conditions, which can promote studies in veterinary and consequently human regenerative medicines.

Generation, characterization, and differentiation of induced pluripotent stem-like cells in the domestic cat

Induced pluripotent stem (iPS) cells are generated from somatic cells and can differentiate into various cell types. Therefore, these cells are expected to be a powerful tool for modeling diseases and transplantation therapy. Generation of domestic cat iPS cells depending on leukemia inhibitory factor has been reported; however, this strategy may not be optimized. Considering that domestic cats are excellent models for studying spontaneous diseases, iPS cell generation is crucial. In this study, we aimed to derive iPS cells from cat embryonic fibroblasts retrovirally transfected with mouse Oct3/4, Klf4, Sox2, and c-Myc. After transfection, embryonic fibroblasts were reseeded onto inactivated SNL 76/7 and cultured in a medium supplemented with basic fibroblast growth factor. Flat, compact, primary colonies resembling human iPS colonies were observed. Additionally, primary colonies were more frequently observed in the KnockOut Serum Replacement medium than in the fetal bovine serum (FBS) medium. However, enhanced maintenance and proliferation of iPS-like cells occurred in the FBS medium. These iPS-like cells expressed embryonic stem cell markers, had normal karyotypes, proliferated beyond 45 passages, and differentiated into all three germ layers in vitro. Notably, expression of exogenous Oct3/4, Klf4, and Sox2 was silenced in these cells. However, the iPS-like cells failed to form teratomas. In conclusion, this is the first study to establish and characterize cat iPS-like cells, which can differentiate into different cell types depending on the basic fibroblast growth factor.

In vivo transfection of cytokine genes into tumor cells using a synthetic vehicle promotes antitumor immune responses in a visceral tumor model

The tumor microenvironment (TME) strongly affects the clinical outcomes of immunotherapy. This study aimed to activate the antitumor immune response by manipulating the TME by transfecting genes encoding relevant cytokines into tumor cells using a synthetic vehicle, which is designed to target tumor cells and promote the expression of transfected genes. Lung tumors were formed by injecting CT26.WT intravenously into BALB/c mice. Upon intravenous injection of the green fluorescent protein-coding plasmid encapsulated in the vehicle, 14.2% tumor-specific expression was observed. Transfection of the granulocyte-macrophage colony-stimulating factor (GM-CSF) and CD40 ligand (L)-plasmid combination and interferon gamma (IFNγ) and CD40L-plasmid combination showed 45.5% and 54.5% complete remission (CR), respectively, on day 60; alternate treatments with both the plasmid combinations elicited 66.7% CR, while the control animals died within 48 days. Immune status analysis revealed that the density of dendritic cells significantly increased in tumors, particularly after GM-CSF- and CD40L-gene transfection, while that of regulatory T cells significantly decreased. The proportion of activated killer cells and antitumoral macrophages significantly increased, specifically after IFNγ and CD40L transfection. Furthermore, the level of the immune escape molecule programmed death ligand-1 decreased in tumors after transfecting these cytokine genes. As a result, tumor cell-specific transfection of these cytokine genes by the synthetic vehicle significantly promotes antitumor immune responses in the TME, a key aim for visceral tumor therapy.

Formation and evolution of carbonaceous asteroid Ryugu: Direct evidence from returned samples

Samples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed 17 Ryugu samples measuring 1 to 8 millimeters. Carbon dioxide-bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu's parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and calcium- and aluminum-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed through aqueous alteration reactions at low temperature, high pH, and water/rock ratios of <1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate that Ryugu's parent body formed ~2 million years after the beginning of Solar System formation.

Mesenteric lymph node abscesses due to Escherichia coli in a cat

A 3-year-old, castrated male mixed-breed cat presented with an almost 2-year history of chronic loose stools. On radiography and ultrasound examination, there were two masses in the centre of the abdomen. Contrast-enhanced computed tomography revealed that the masses were enlarged mesenteric lymph nodes with fluid accumulation. Percutaneous lesion drainage yielded pus-like fluid. Fluid cytology revealed numerous neutrophils and Gram-negative rods. Pus culture identified Escherichia coli as the causative organism. Consequently, mesenteric lymph node abscesses were definitively diagnosed. Since computed tomography showed that the abscesses adhered to the surrounding tissues, it was difficult to remove them surgically. With drainage and antimicrobial therapy, the mesenteric lymph nodes gradually decreased in size. However, loose stools persisted. The cat's diet was changed to a hydrolysed diet, and the clinical symptoms improved, suggesting food-responsive enteropathy. This may be an underlying disease of lymph node abscesses. Lymph node abscesses limited to the mesenteric lymph nodes rarely occur in veterinary medicine, and this is the first report in cats.

Generation of molecular-targeting helix-loop-helix peptides for inhibition of the interaction between cytotoxic T-lymphocyte-associated protein 4 and B7 in the dog

Blocking the interaction between CD28 and B7 by cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) is a potent immune checkpoint that prevents damage to host tissues from excessive immune responses. However, it also significantly diminishes immune responses against cancers and allows cancer cell growth. This study found that recombinant (r) human (h) CTLA-4 specifically binds to canine dendritic cells (DCs) and suppresses the responses of canine T cells to allogeneic DCs. ERY2-4, a peptide targeting rhCTLA-4 selected from a yeast-displayed library of helix-loop-helix (HLH) peptides and improved to have a binding affinity to rhCTLA-4 as strong as that of rhB7, inhibited the binding of rhCTLA-4 to canine DCs. Furthermore, the targeting peptide significantly enhanced the response of canine T cells to allogeneic DCs. These results suggest that the CTLA-4-targeting peptide enhances canine T cell activity by blocking the interaction between canine CTLA-4 on T cells and canine B7 on DCs. This study demonstrates the generation of a new type of immune checkpoint inhibitor, which may be applicable to cancer therapy in dogs.

New Class of Drug Modalities: Directed Evolution of a De Novo Designed Helix-Loop-Helix Peptide to Bind VEGF for Tumor Growth Inhibition

As a small affinity molecule to serve as an alternative to antibodies, we have developed a conformationally constrained peptide with a de novo designed helix-loop-helix (HLH) scaffold. To evaluate its potential for biomedical applications, we performed directed evolution of HLH peptides to obtain an inhibitor for vascular endothelial growth factor-A (VEGF). A phage-displayed library of HLH peptides was constructed and screened against VEGF, giving the peptide VS42 that inhibits the VEGF/VEGF receptor-2 interaction (IC₅₀ = 210 nM), which was further improved by in vitro affinity maturation using a yeast-displayed library. An identified HLH peptide, VS42-LR3, exhibited improved inhibitory activity (IC₅₀ = 37 nM), high thermal stability, and excellent resistance against chemical denaturation. In biological activity tests, the HLH peptide was found to block VEGF-induced proliferation of human umbilical vein endothelial cells and suppress tumor growth in a murine xenograft model of human colorectal cancer.

Potent adjuvant effect elicited for tumor immunotherapy by a liposome conjugated pH-sensitive polymer and dendritic cell-targeting Toll-like-receptor ligand

The generation of DCs with augmented functions is a strategy for obtaining satisfactory clinical outcomes in tumor immunotherapy. We developed a novel synthetic adjuvant comprising a liposome conjugated with a DC-targeting Toll-like-receptor ligand and a pH-sensitive polymer for augmenting cross-presentation. In an in vitro study using mouse DCs, these liposomes were selectively incorporated into DCs, significantly enhanced DC function and activated immune responses to present an epitope of the incorporated antigen on the major histocompatibility complex class I molecules. Immunization of mice with liposomes encapsulating a tumor antigen significantly enhanced antigen-specific cytotoxicity. In tumor-bearing mice, vaccination with liposomes encapsulating a tumor antigen elicited complete tumor remission. Furthermore, vaccination significantly enhanced cytotoxicity, targeting not only the vaccinated antigen but also the other antigens of the tumor cell. These results indicate that liposomes are an ideal adjuvant to develop DCs with considerably high potential to elicit antigen-specific immune responses; they are a promising tool for cancer therapy with neoantigen vaccination.

Effects of the preservation medium and storage duration of domestic cat ovaries on the maturational and developmental competence of oocytes in vitro

We examined the effectiveness of saline, Euro-Collins solution (EC), and ET-Kyoto solution (ET-K) as preservation media for the cold storage of feline ovaries. Ovaries were maintained in these media at 4°C for 24, 48, or 72 h until oocyte retrieval. The ET-K group exhibited a higher oocyte maturation rate than the saline group after 72 h of storage. Moreover, ET-K could sustain the competence of the feline oocytes to cleave after 48 h, and the morula formation rate of the ET-K group was higher than that of the other groups after 24 and 48 h. Furthermore, the ET-K group exhibited a higher blastocyst formation rate than the other groups after storage for 24 h, and only ET-K retained the developmental competence in blastocysts after 48 h of storage. In addition, regarding the cell numbers of the blastocysts, there was no significant difference among the tested groups. In conclusion, our results indicate that ET-K is a suitable preservation medium for feline ovaries.

Cutaneous ischemia-reperfusion injury is exacerbated by IL-36 receptor antagonist deficiency

BACKGROUND

Loss-of-function homozygous or compound heterozygous mutations in IL36RN, which encodes interleukin-36 receptor antagonist (IL-36Ra), has been implicated in the pathogenesis of skin disorders. However, the pathogenic role of IL-36Ra in cutaneous ischemia-reperfusion (I/R) injury remains unclear.

OBJECTIVES

We investigated the role of IL36Ra in cutaneous I/R injury.

METHODS

We examined I/R injury in Il36rn^-/- mice. The area of wounds, numbers of infiltrated cells, apoptotic cells and neutrophil extracellular trap (NET) formation were assessed. The expression levels of various genes were analysed using real-time RT-PCR. The expression of high mobility group box 1 (HMGB1), an endogenous toll-like receptor (TLR) 4 ligand, was confirmed using immunohistology, and serum HMGB1 levels were measured by ELISA. Cytokine production by stimulated cultured J774A.1 and HaCaT cells was examined.

RESULTS

IL-36Ra deficiency resulted in significantly delayed wound healing and increased neutrophil and macrophage infiltration into the wound tissues. Il36rn^-/- mice had increased mRNA expression levels of CXCL1, CXCL2, CCL4, TNF-α, TGF-β, IL-1β, IL-6 and IL-36γ relative to wild-type mice. Apoptosis was identified in keratinocytes by TUNEL assay. HMGB1 expression in the I/R site was decreased in both keratinocytes and adnexal cells, while serum HMGB1 levels were significantly elevated after reperfusion. The mRNA levels of various cytokines, including IL-1β, were elevated in J774A.1 cells through TLR4 signalling by HMGB1 stimulation. In addition, HaCaT cells stimulated with IL-1β showed significantly increased CXCL1, TNF-α, IL-6, IL-36β and IL-36γ mRNA expression. Furthermore, NET formation was increased by IL-36Ra deficiency. Finally, either the blockade of TLR4 signalling by TAK-242 or inhibition of NET formation by Cl-amidine normalized exacerbated I/R injury in Il36rn^-/- mice.

CONCLUSIONS

This study indicated that IL-36Ra deficiency exacerbates cutaneous I/R injury due to excessive inflammatory cell recruitment, NET formation, and excessive cytokine and chemokine production via the TLR4 pathway by HMGB1 released from epidermal apoptotic cells.

Quality of life-improving effect of autologous ex vivo expanded cytotoxic and opioid-producing lymphocytes for dogs with cancers

Activated lymphocyte therapy is one of the immunotherapies for cancer patients that is expected to prolong life without any adverse effects and maintain satisfactory quality of life (QOL). However, the objective assessment and maintenance of a standardized evaluation of QOL are not easy. We aimed to evaluate activated autologous lymphocyte therapy for cancer dogs using the characteristics of the cultured cells and QOL as perceived by owners. In in vitro experiments, peripheral blood mononuclear cells (PBMCs) collected from healthy dogs were stimulated using anti-CD3 antibody and recombinant interleukin-2 under a closed system. The number of CD4⁺ and CD8⁺ T lymphocytes in the cultured cells was higher than that of PBMCs (P < 0.05). Natural killer activity, proenkephalin (known as the precursor of endogenous opioids) and interferon-γ mRNA in activated lymphocytes were significantly higher than in PBMCs (P < 0.05). Met-enkephalin was detected in activated lymphocytes. QOL of 58 dogs afflicted with common types of cancers in humans increased after every administration of activated lymphocyte therapy (P < 0.05). Overall, these results indicated that activated lymphocyte therapy could have beneficial effects on QOL in dogs with cancers. This was objectively evaluated and this improvement was related to presence of opioid-producing lymphocytes.

Application of Zwitterionic Polymer Hydrogels to Optical Tissue Clearing for 3D Fluorescence Imaging

Zwitterionic polymers have both anion and cation groups in the side chain and have been used in various biomedical applications because of the unique properties. In this study, zwitterionic polymer hydrogels are applied to optical tissue clearing for 3D fluorescence imaging. Polyacrylamide hydrogels have been employed in Clear Lipid-exchanged Acrylamide-hybridized Rigid Imaging/Immunostaining/In situ-hybridization-compatible Tissue-hYdrogel method. Zwitterionic polymer hydrogels are produced using zwitterionic monomers, such as 3-[(3-acrylamidopropyl)dimethylammonio]propane-1-sulfonate (DAPS) and 2-methacryloyloxyethyl phosphorylcholine (MPC), and crosslinkers. The hydrogels made from poly(DAPS-co-acrylamide) and MPC homopolymers afford the most transparent tumor tissues. However, the tissues cleared using DAPS copolymers-containing hydrogels became turbid in a refractive index-matching solution, which are unable to obtain clear 3D fluorescence images. In contrast, the 3D fluorescence imaging is achieved in the MPC polymer-treated 2-mm-thick brain slices after immunostaining. The 3D fluorescence imaging of lung metastasis that is cleared by the MPC hydrogel to demonstrate the possible application to cancer diagnosis is performed. The results indicate the increased potentials of zwitterionic polymer hydrogels, especially MPC polymer hydrogels, in biomedical applications.

Canine induced pluripotent stem cell maintenance under feeder-free and chemically-defined conditions

Canine induced pluripotent stem cells (ciPSCs) provide a platform for regenerative veterinary medicine, disease modeling, and drug discovery. However, in the conventional method, ciPSCs are maintained using chemically-undefined media containing unknown animal components under on-murine embryonic fibroblast feeder conditions, which were reported to modify cell surface of iPSCs and increases the risk of immune rejection when the cells are transplanted into patients. Moreover, in the conventional method, ciPSCs are mechanically passaged, which requires much time and effort. Therefore, the large-scale expansion of ciPSCs is difficult, which should be resolved for using ciPSCs in clinical application and research. Here, it was shown that StemFit® AK02N and iMatrix-511 could maintain the pluripotency of ciPSCs using conventional culture method. Furthermore, it was demonstrated that the feeder-free and chemically-defined ciPSC culture systems using StemFit® AK02N and iMatrix-511 could stably maintain and allow the easy expansion of ciPSCs generated using N2B27 and StemFit® AK02N, without causing karyotype abnormalities. ciPSCs expressed several pluripotency markers and formed teratomas, including cells derived from three germ layers.

Long-Term Trypsin Treatment Promotes Stem Cell Potency of Canine Adipose-Derived Mesenchymal Stem Cells

Mesenchymal stem cells (MSCs) isolated from adipose tissue (adipose-derived stem cells [ADSCs]) are considered one of the most promising cell types for applications in regenerative medicine. However, the regenerative potency of ADSCs may vary because of heterogeneity. Long-term trypsin treatment (LTT) is known to significantly concentrate multilineage-differentiating stress-enduring (Muse) cells from human MSCs. In this study, we aimed to generate cells with high stem cell potency from canine ADSCs using LTT. After 16 h of treatment with trypsin, surviving ADSCs (LTT-tolerant cells) had significantly enhanced expression of stage-specific embryonic antigen (SSEA)-1, a mouse embryonic stem cell marker, and fucosyltransferase 9, one of several fucosyltransferases for SSEA-1 biosynthesis. However, LTT-tolerant cells did not enhance the expression of SSEA-3, a known human Muse cell marker. LTT-tolerant cells, however, showed significantly higher self-renewal capacity in the colony-forming unit fibroblast assay than ADSCs. In addition, the LTT-tolerant cells formed cell clusters similar to embryoid bodies and expressed undifferentiated markers. Moreover, these cells differentiated into cells of all three germ layers and showed significantly higher levels of α 2-6 sialic acid (Sia)-specific lectins, known as differentiation potential markers of human MSCs, than ADSCs. LTT-tolerant cells had a normal karyotype and had low telomerase activity, showing little carcinogenetic potency. LTT-tolerant cells also showed significantly increased activity of transmigration in the presence of chemoattractants and had increased expression of migration-related genes compared with ADSCs. In addition, LTT-tolerant cells had stronger suppressive activity against mitogen-stimulated lymphocyte proliferation than ADSCs. Overall, these results indicated that the LTT-tolerant cells in canine ADSCs have similar properties as human Muse cells (although one of the undifferentiated markers is different) and are expected to be a promising tool for regenerative therapy in dogs.

Efficient Reprogramming of Canine Peripheral Blood Mononuclear Cells into Induced Pluripotent Stem Cells

Forced coexpression of the transcription factors Oct3/4, Klf4, Sox2, and c-Myc reprograms somatic cells into pluripotent stem cells (PSCs). Such induced PSCs (iPSCs) can generate any cell type of the adult body or indefinitely proliferate without losing their potential. Accordingly, iPSCs can serve as an unlimited cell source for the development of various disease models and regenerative therapies for animals and humans. Although canine peripheral blood mononuclear cells (PBMCs) can be easily obtained, they have a very low iPSC reprogramming efficiency. In this study, we determined the reprogramming efficiency of canine PBMCs under several conditions involving three types of media supplemented with small-molecule compounds. We found that canine iPSCs (ciPSCs) could be efficiently generated from PBMCs using N2B27 medium supplemented with leukemia inhibitory factor (LIF), basic fibroblast growth factor (bFGF), and a small-molecule cocktail (Y-27632, PD0325901, CHIR99021, A-83-01, Forskolin, and l-ascorbic acid). We generated five ciPSC lines that could be maintained in StemFit® medium supplemented with LIF. The SeVdp(KOSM)302L vectors were appropriately silenced in four ciPSC lines. Of the two lines characterized, both were positive for alkaline phosphatase activity and expressed pluripotency markers, including the Oct3/4, Sox2, and Nanog transcripts, as well as the octamer-binding transcription factor (OCT) 3/4 and NANOG proteins, and the SSEA-1 carbohydrate antigen. The ciPSCs could form embryoid bodies and differentiate into the three germ layers, as indicated by marker gene and protein expression. Furthermore, one ciPSC line formed teratomas comprising several tissues from every germ layer. Our ciPSC lines maintained a normal karyotype even after multiple passages. Moreover, our new reprogramming method was able to generate ciPSCs from multiple donor PBMCs. In conclusion, we developed an easy and efficient strategy for the generation of footprint-free ciPSCs from PBMCs. We believe that this strategy can be useful for disease modeling and regenerative medicine in the veterinary field.

Microbial Antigen-Presenting Extracellular Vesicles Derived from Genetically Modified Tumor Cells Promote Antitumor Activity of Dendritic Cells

Tumor-derived extracellular vesicles (EVs), as tumor vaccines, carry tumor-associated antigens (TAAs), and were expected to transfer TAAs to antigen-presenting cells. However, treatment with tumor-derived EVs exhibited no obvious antitumor effect on the established tumors, likely due to their immuno-suppressive functions, and also to the poor immunogenicity of TAAs. In order to improve the immune stimulating properties, EVs expressing a highly immunogenic bacterial antigen, 6 kDa early secretory antigenic target (ESAT-6), from Mycobacterium tuberculosis were prepared by genetically modifying the parent tumor cells with a plasmid coding for ESAT-6. Cultured B16 tumor cells were transfected with a ternary complex system consisting of pDNA, polyethylenimine (PEI), and chondroitin sulfate. The cells that were transfected with the ternary complex secreted EVs with a higher number of ESAT-6 epitopes than those transfected by a conventional DNA/PEI binary complex, due to the low cytotoxicity, and durable high expression efficiency of the ternary complex systems. The EVs presenting the ESAT-6 epitope (ESAT-EV) were collected and explored as immune modulatory agents. Dendritic cells (DCs) were differentiated from mouse bone marrow cells and incubated with ESAT-EV. After incubating with the EVs for one day, the DCs expressed a significantly higher level of DC maturation marker, CD86. The DCs treated with ESAT-EV showed a significantly improved antitumor activity in tumor-bearing mice.

Prognostic impact of atrial fibrillation in patients with hypertrophic cardiomyopathy in a community-based Japanese cohort: results from Kochi RYOMA study

Background

The prognostic impact of atrial fibrillation (AF) in patients with hypertrophic cardiomyopathy (HCM) is not fully elucidated.

Purpose

The aim of this study was to examine the prevalence and prognostic impact of AF in a prospectively assembled community-based HCM patient cohort in an aged Japanese community.

Methods

In 2004, we established a cardiomyopathy registration network in Kochi Prefecture, Japan, consisting of 9 hospitals, and finally 293 patients with HCM were followed.

Results

The ages at registration and at diagnosis were 63±14 and 56±16 years, respectively, and 197 patients (67%) were men. 86 patients (29%) showed AF. During follow-up period of 6.1±3.2 years, 44 patients died. In those patients, HCM-related deaths occurred in 23 patients with an annual mortality rate of 1.3%. Regarding HCM-related adverse events including HCM-related deaths, appropriate ICD discharge, heart failure admission and hospitalization for embolic events, a total of 77 cardiovascular events in 70 patients occurred. Multivariate analysis revealed that presence of AF, left ventricular (LV) outflow obstruction, NYHA functional class III, and lower LV fractional shortening at registration were significant predictors of these adverse events. During the follow-up period, additional 31 patients (11%) developed new-onset AF. Importantly, the incidence of HCM-related adverse events was significantly higher in patients with new AF observed from its onset compared with those with AF at registration (log-rank p=0.029) (Figure 1).

Conclusions

In an unselected HCM registry in an aged Japanese community, presence of AF, particularly new-onset AF, was associated with unfavorable clinical outcomes. AF is not just a marker of the disease stage but an important trigger of HCM-related adverse events.

Figure 1

Funding Acknowledgement

Type of funding source: None

Canine mesenchymal stromal cell-conditioned medium promotes survival and neurite outgrowth of neural stem cells

We examined the paracrine action of canine mesenchymal stromal cells (MSCs) derived from bone marrow on the survival and differentiation of neural stem cells (NSCs) in vitro. MSCs were collected from the proximal end of the diaphysis of femur of healthy beagle dogs. The 70–80% confluent MSCs were re-fed with serum-free DMEM. The MSCs were incubated for 48 hr and the supernatant was collected as the conditioned medium (MSC-CM). The survival rate of NSCs in MSC-CM was significantly greater than in the medium without MSC-CM. The percentage of differentiated neurons and neurite length in MSC-CM was also significantly higher than in the medium without MSC-CM. These results suggested that canine MSC-CM promotes stem cell survival and neural differentiation of NSCs.

An Immune-Stimulatory Helix-Loop-Helix Peptide: Selective Inhibition of CTLA-4-B7 Interaction

Molecular-targeting peptides and mini-proteins are promising alternatives to antibodies in a wide range of applications in bioscience and medicine. We have developed a helix-loop-helix (HLH) peptide as an alternative to antibodies to inhibit specific protein interactions. Cytotoxic T lymphocyte antigen-4 (CTLA-4) downregulates immune responses of cytotoxic T-cells by interaction with B7-1, a co-stimulatory molecule expressed on antigen presenting cells (APCs). To induce immune stimulatory activity, we used directed evolution methods to generate a HLH peptide that binds to CTLA-4, inhibiting the CTLA-4-B7-1 interaction and inducing immune stimulatory activity. Yeast-displayed libraries of HLH peptides were constructed and screened against CTLA-4 and identified the binding peptide Y-2, which exhibits a moderate affinity. The affinity of Y-2 was improved by in vitro affinity maturation to afford a stronger binder, ERY2-4. Peptide ERY2-4 specifically bound to CTLA-4 with a K_D of 196.8 ± 2.3 nM, comparable to the affinity of the CTLA-4-B7-1 interaction. Furthermore, ERY2-4 inhibited the CTLA-4-B7-1 interaction with an IC₅₀ of 1.1 ± 0.03 μM and blocked the interaction between CTLA-4 and dendritic cells (DCs) presenting B7 on their surface. Importantly, ERY2-4 showed no cross-reactivity against CD28, suggesting it does not suppress T-cell activation. Finally, in a mixed lymphocyte reaction assay with DCs and T cells, ERY2-4 enhanced an allogeneic lymphocyte response. Since CTLA-4 is a critical immune checkpoint for restricting the cancer immune response, this inhibitory HLH peptide represents a new class of drug candidates for immunotherapy.

Manipulation of the tumor microenvironment by cytokine gene transfection enhances dendritic cell-based immunotherapy

The tumor microenvironment strongly influences clinical outcomes of immunotherapy. By transfecting genes of relevant cytokines into tumor cells, we sought to manipulate the microenvironment so as to elicit activation of T helper type 1 (Th1) responses and the maturation of dendritic cells (DCs). Using a synthetic vehicle, the efficiency of in vivo transfection of GFP-cDNA into tumor cells was about 7.5% by intratumoral injection and about 11.5% by intravenous injection. Survival was significantly improved by both intratumoral and intravenous injection of the plasmid containing cDNA of interferon-gamma, followed by intratumoral injection of DCs presenting the tumor antigens. Also, tumor growth was inhibited by these treatments. A more significant effect on survival and tumor growth inhibition was observed following injection of the plasmid containing cDNA of CD40 ligand, which is a potent inducer of DC-maturation. Furthermore, the co-injection of both IFNγ- and CD40 ligand-encoding cDNA-plasmids, followed by DC treatment, gave rise to further marked and enhancement, including 100% survival and more than 50% complete remission. This treatment regimen elicited significant increases in mature DCs and types of cells contributing to Th1 responses, and significant decreases in immune suppressor cells in the tumor. In the spleen, the treatment significantly increased activities of tumor-specific killer and natural killer cells, but no alteration was observed in mature DCs or suppressor cells. These results indicate that transfection of these cytokine genes into tumor cells significantly alter the tumor microenvironment and improve the therapeutic results of DC-based immunotherapy.

Clinical findings and treatment of disseminated 'Mycobacterium avium subspecies hominissuis' infection in a domestic cat

A cat was referred because of diffuse parenchymal lung disease. Close examinations revealed a swollen abdominal lymph node and multiple nodules of the liver. Mycobacterium avium subspecies hominissuis infection was confirmed by culture and single nucleotide polymorphism analysis of samples recovered from the liver and bronchoalveolar lavage. After administration of combination antibiotics for 6 months, culture results were negative. Though atonic seizures were observed during the treatment, it disappeared after isoniazid discontinuation and pyridoxal phosphate administration. On day 771 of illness, no clinical signs, lung diseases, or obvious swelling of lymph nodes was observed. This is the first report to confirm Mycobacterium avium subspecies hominissuis infection in cats through gene analysis and to completely cure it with combination antibiotics.

Feline embryo development in commercially available human media supplemented with fetal bovine serum

Feline embryo development was examined for 7 days after fertilization using commercially available human media supplemented with 0.3% bovine serum albumin (BSA) or 5% fetal bovine serum (FBS). Cumulus-oocyte complexes were categorized as Grades 1, 2, and 3 according to morphology. Only-One Medium (OM) was used for in vitro culture (IVC) in OM + BSA, OM + FBS, and OM + BSA/FBS, with BSA supplementation for the first 2 days and FBS for the subsequent 5 days. Embryos cultured in Early Culture Medium (1–2 days) and Blastocyst Medium (3–7 days) were defined as EB + BSA and EB + BSA/FBS. The developmental rate until the blastocyst stage of Grade 1 and 2 oocytes cultured in OM + BSA/FBS was higher than for the other groups and was significantly higher than for the OM + BSA and EB + BSA groups (P<0.01). Grade 3 oocytes cultured in OM + BSA/FBS also showed the greatest proportion of blastocyst formation. However, FBS supplementation throughout the IVC period reduced blastocyst number. The percentage of 2 pronuclei after fertilization as well as blastocyst cell number were significantly higher in Grade 1 and 2 than Grade 3 oocytes when cultured in OM + BSA/FBS (P<0.05). These results indicate that commercially available OM supplemented with BSA for the first 2 days of culture and FBS for the subsequent 5 days is suitable for feline embryo development until the blastocyst stage.

Development of feline embryos produced by Piezo-actuated intracytoplasmic sperm injection of elongated spermatids

Piezo-actuated intracytoplasmic sperm injection (Piezo-ICSI) is used as an efficient in vitro fertilization method with various animals. With this method, elongated spermatids are collected from testicular tissues and are easier to obtain from animals that unexpectedly die than ejaculate sperm. Additionally, elongated spermatid injection often results in the development of embryos and offspring. To develop assisted reproductive techniques (ARTs) for domestic cats, we examined the effects of oocyte activation on cleavage and embryo development after Piezo-ICSI with motile sperm (experiment 1) and after Piezo-ICSI with either testicular sperm or elongated spermatids (experiment 2). In experiment 1, the proportions of cleaved embryos, morulas, and blastocysts following Piezo-ICSI with ethanol activation were significantly higher (P < 0.05) than in the non-activated groups. However, the proportion of blastocysts and the blastocyst quality did not differ significantly (P > 0.05) between the ethanol-activated and non-activated groups. In experiment 2, the cleavage frequencies of oocytes after Piezo-ICSI of testicular sperm or elongated spermatids and ethanol activation were higher (P < 0.05) than that of oocytes in the non-activated group, but the occurrence of blastocyst formation and quality of blastocysts did not differ between the activated and non-activated groups. In summary, cat embryos can be produced by Piezo-actuated microinjection of elongated spermatids. Ethanol activation increased the frequency of cleavage, but it affected neither the occurrence of blastocyst development nor the quality of blastocysts. These results represent an expansion in the repertoire of ARTs that are potentially applicable to both domestic and endangered species of cats.

Generation of Footprint-Free Canine Induced Pluripotent Stem Cells Using Auto-Erasable Sendai Virus Vector

Canine induced pluripotent stem cells (ciPSCs) can be used in regenerative medicine. However, there are no reports on the generation of genome integration-free and completely exogenous gene-silenced (footprint free) ciPSCs that are tolerant to enzymatic single-cell passage. In this study, we reprogrammed canine embryonic fibroblasts using the auto-erasable replication-defective and persistent Sendai virus vector, SeVdp(KOSM)302L, and generated two ciPSC lines. The ciPSCs were positive for pluripotent markers, including alkaline phosphatase activity as well as OCT3/4, SOX2, and NANOG transcripts, and NANOG, stage-specific embryonic antigen-1, and partial TRA-1-60 protein expression, even after SeVdp(KOSM)302L removal. The ciPSCs were induced to differentiate into all the three germ layers as embryoid bodies in vitro and as teratomas in vivo. Furthermore, SeVdp(KOSM)302L-free ciPSCs maintained a normal karyotype even after repeated enzymatic single-cell passaging. Therefore, to our knowledge, for the first time, we demonstrated the generation of footprint-free and high-quality ciPSCs that can be passaged at the single-cell stage using enzymatic methods. Our method for generation of ciPSCs is a good step toward the development of clinical application of ciPSCs.

Roles of aberrant hemichannel activities due to mutant connexin26 in the pathogenesis of KID syndrome

Germline missense mutations in GJB2 encoding connexin (Cx) 26 have been found in keratitis, ichthyosis and deafness (KID) syndrome. We explored the effects of three mouse Cx26 mutants (Cx26-G12R, -G45E and -D50N) corresponding to KID syndrome-causative human mutants on hemichannel activities leading to cell death and the expression of immune response-associated genes. We analyzed the 3D images of cells expressing wild-type (WT) or mutant Cx26 molecules to demonstrate clearly the intracellular localization of Cx26 mutants and hemichannel formation. High extracellular Ca²⁺ conditions lead to the closure of gap junction hemichannels in Cx26-G12R or Cx26-G45E expressing cells, resulting in prohibition of the Cx26 mutant-induced cell death. Fluorescent dye uptake assays revealed that cells with Cx26-D50N had aberrantly high hemichannel activities, which were abolished by a hemichannel blocker, carbenoxolone and 18α-Glycyrrhetinic acid. These results further support the idea that abnormal hemichannel activities play important roles in the pathogenesis of KID syndrome. Furthermore, we revealed that the expressions of IL15, CCL5, IL1A, IL23R and TLR5 are down-regulated in keratinocytes expressing Cx26-D50N, suggesting that immune deficiency in KID syndrome expressing Cx26-D50N might be associated not only with skin barrier defects, but also with the down-regulated expression of immune response-related genes.

Physiological Effects of Nonimmune Platelet Associated Immunoglobulin G

The function of nonimmune IgG associated with platelets is unknown. In a series of experiments we have investigated this problem, relating amount of platelet-associated IgG (PAIgG) to platelet volume, serotonin release, adherence of platelets to monocytes and platelet senescence. Most of these studies were performed with human platelets. Platelets freed of preexisting PAIgG by incubation at 22° C were incubated with IgG in a series of concentrations ranging from 0.4 — 27.0 X10-6 M. The IgG preparations used were demonstrably free of aggregated forms of the protein. The amount of PAIgG bound to platelets was determined by the use of fluorescein isothiocyanate-conjugated anti-IgG antibody (F-anti-IgG antibody) which was quantified in a fluorospectrophotometer. Newly bound IgG was assayed similarly by the use of F-IgG. A dose-dependent increase in platelet volume was associated with the binding of nonimmune IgG by platelets. The process which leveled off at an IgG concentration of 1.2 —1.5 X10-5 M was almost fully reversible and was not due to platelet shape change or aggregation. Release of serotonin from IgG-treated platelets was relatively small but to the extent that it occurred was positively related to the IgG concentration to which platelets were exposed. Adherence to autologous monocytes studied quantitatively by the use of formaldehyde-fixed cells was also positively related to the amount of IgG on the platelets. Normal or IgG-defident serum had a potent inhibitory (noncompetitive) action on the binding of F-IgG and F-anti-human IgG antibody to human platelets. Cohorts of platelets prepared in rabbits during the recovery phase of immunological thrombocytopenia induced by injection of heterologous antiserum, showed an age-dependent increase of PAIgG and of IgG binding. These results suggest that PAIgG plays a role in the clearance of senescent platelets.

Development of a vaccine based on bacteria-mimicking tumor cells coated with novel engineered toll-like receptor 2 ligands

For a successful tumor vaccine, it is necessary to develop effective immuno-adjuvants and identify specific tumor antigens. Tumor cells obtained from surgical or biopsy tissues are a good source of tumor antigens but, unlike bacteria, they do not induce strong immune responses. Here, we designed 2 novel lipopeptides that coat tumor cell surfaces and mimic bacterial components. Tumor cells coated with these lipopeptides (called bacteria-mimicking tumor cells [BMTC]) were prepared and their efficacy as a tumor vaccine examined. Natural bacterial lipopeptides act as ligands for toll-like receptor 2 (TLR2) and activate dendritic cells (DC). To increase the affinity of the developed lipopeptides for the negatively charged plasma membrane, a cationic polypeptide was connected to Pam2Cys (P2C), which is the basic structure of the TLR2 ligand. This increased the non-specific binding affinity of the peptides for the cell surface. Two such lipopeptides, P2CSK11 (containing 1 serine and 11 lysine residues) and P2CSR11 (containing 1 serine and 11 arginine residues) bound to irradiated tumor cells via the long cationic polypeptides more efficiently than the natural lipopeptide MALP2 (P2C-GNNDESNISFKEK) or a synthetic lipopeptide P2CSK4 (a short cationic polypeptide containing 1 serine and 4 lysines). BMTC coated with P2CSR11 or P2CSK11 were efficiently phagocytosed by DC and induced antigen cross-presentation in vitro. They also induced effective tumor-specific cytotoxic T cell responses and inhibited tumor growth in in vivo mouse models. P2CSR11 activated DC but induced less inflammation-inducing cytokines/interferons than other lipopeptides. Thus, P2CSR11 is a strong candidate antigen-specific immuno-adjuvant, with few adverse effects.

Innate immunity mediated by dendritic cells/macrophages plays a central role in the early period in tumor treatment using gene of Mycobacterium tuberculosis antigen

By using a complex of DNA, polyethylenimine and chondroitin sulfate, the in vivo transfection of early secretory antigenic target-6 (ESAT-6) gene into tumor cells was found to cause significant suppression of the tumor growth. In order to apply the method in clinical cancer treatment in dogs and cats, mechanisms underlying the suppressive effects were investigated in a tumor-bearing mouse model. The transfection efficiency was only about 10%, but the transfection of ESAT-6 DNA nevertheless induced systemic immune responses against ESAT-6. By triple injection of ESAT-6 DNA at three day intervals, the tumor was significantly reduced and almost disappeared by 5 days after the start of treatment, and did not increase for more than 15 days after the final treatment. In the immunohistochemistry, a larger number of dendritic cells (DCs)/macrophages expressing ionized calcium-binding adapter molecule 1 and CD3⁺ T cells was observed in tumors treated with ESAT-6 DNA, and their population further increased significantly by day 5. Moreover, the amount of tumor necrosis factor, which is an apoptosis-inducing factor produced mainly by DCs/macrophages, was greater in the ESAT-6 DNA treated tumors than in controls, and increased with repeat of the treatment. These results indicate that in vivo transfection of ESAT-6 DNA into tumor cells elicits significant inhibition of tumor growth by inducing potent activity of innate immunity mediated by DCs/macrophages, which may be followed by adaptive immunity against tumor associated antigens, elicited by the costimulation with ESAT-6 antigen.

Involvement of nitric oxide/reactive oxygen species signaling via 8-nitro-cGMP formation in 1-methyl-4-phenylpyridinium ion-induced neurotoxicity in PC12 cells and rat cerebellar granule neurons

To investigate the role of nitric oxide (NO)/reactive oxygen species (ROS) redox signaling in Parkinson's disease-like neurotoxicity, we used 1-methyl-4-phenylpyridinium (MPP⁺) treatment (a model of Parkinson's disease). We show that MPP⁺-induced neurotoxicity was dependent on ROS from neuronal NO synthase (nNOS) in nNOS-expressing PC12 cells (NPC12 cells) and rat cerebellar granule neurons (CGNs). Following MPP⁺ treatment, we found production of 8-nitroguanosine 3',5'-cyclic monophosphate (8-nitro-cGMP), a second messenger in the NO/ROS redox signaling pathway, in NPC12 cells and rat CGNs, that subsequently induced S-guanylation and activation of H-Ras. Additionally, following MPP⁺ treatment, extracellular signal-related kinase (ERK) phosphorylation was enhanced. Treatment with a mitogen-activated protein kinase (MAPK)/ERK kinase (MEK) inhibitor attenuated MPP⁺-induced ERK phosphorylation and neurotoxicity. In conclusion, we demonstrate for the first time that NO/ROS redox signaling via 8-nitro-cGMP is involved in MPP⁺-induced neurotoxicity and that 8-nitro-cGMP activates H-Ras/ERK signaling. Our results indicate a novel mechanism underlying MPP⁺-induced neurotoxicity, and therefore contribute novel insights to the mechanisms underlying Parkinson's disease.

The age, breed and sex pattern of diagnosis for veterinary care in insured cats in Japan

OBJECTIVES

To estimate the annual prevalence of different diagnostic categories by age, breed and sex in insured cats in Japan for which veterinary care claims had been made, and to identify if there is a pattern in these host factors.

MATERIALS AND METHODS

Data from 48,187 cats insured for veterinary care in Japan in the period from April 2012 to March 2013 comprising 26,003 males and 22,184 females were analysed to calculate the annual prevalence of 18 diagnostic categories of disease by age, breed and sex.

RESULTS

The prevalence was highest for urinary system disorders (12·2% for males and 10·0% for females), followed by digestive disorders (11·6% for males and 10·7% for females) and dermatological diseases (8·7% for males and 9·0% for females). The male cats had a higher prevalence than female cats for most diagnostic categories. The prevalence of cardiovascular, urinary, endocrine and neoplastic disorders increased with age; infectious and parasitic diseases had high prevalence at young ages, and the prevalence of respiratory, musculoskeletal disorders and injuries had bimodal peaks. Dermatological disorders had a high prevalence at all ages. A large variation in prevalence was observed between breeds for otic, dermatological, dental and cardiovascular disorders.

CLINICAL SIGNIFICANCE

The findings can be used to increase awareness of patterns of health disorders in different categories of cat.

Generation of Canine Induced Extraembryonic Endoderm-Like Cell Line That Forms Both Extraembryonic and Embryonic Endoderm Derivatives

Extraembryonic endoderm (XEN) cells are stem cell lines derived from primitive endoderm cells of inner cell mass in blastocysts. These cells have self-renewal properties and differentiate into visceral endoderm (VE) and parietal endoderm (PE) of the yolk sac. Recently, it has been reported that XEN cells can contribute to fetal embryonic endoderm, and their unique potency has been evaluated. In this study, we have described the induction and characterization of new canine stem cell lines that closely resemble to XEN cells. These cells, which we designated canine induced XEN (ciXEN)-like cells, were induced from canine embryonic fibroblasts by introducing four transgenes. ciXEN-like cells expressed XEN markers, which could be maintained over 50 passages in N2B27 medium supplemented with inhibitors of mitogen-activated protein kinase p38 and transforming growth factor-beta 1. Our ciXEN-like cells were maintained without transgene expression and exhibited upregulated expression of VE and PE markers in feeder-free conditions. The cells differentiated from ciXEN-like cells using a coculture system showed multiple nuclei and expressed albumin protein, similar to characteristics of hepatocytes. Furthermore, these cells expressed the adult hepatocyte marker, CYP3A4. Interestingly, these cells also formed a net structure expressing the bile epithelium capillary marker, multidrug resistance-associated protein 2. Thus, we have demonstrated the induction of a new canine stem cell line, ciXEN-like cells, which could form an embryonic endodermal cell layer. Our ciXEN-like cells may be a helpful tool to study the canine embryo development and represent a promising cell source for proceeding human and canine regenerative medicine.

Feeder-independent canine induced pluripotent stem cells maintained under serum-free conditions

Canine induced pluripotent stem cells (ciPSCs) are an attractive source for regenerative veterinary medicine, and may also serve as a disease model for human regenerative medicine. Extending the application of ciPSCs from bench to bedside, however, requires resolving many issues. We generated ciPSCs expressing doxycycline-inducible murine Oct3/4 (Pou5f1), Sox2, Klf4, and c-Myc, which were introduced using lentiviral vectors. The resultant ciPSCs required doxycycline to proliferate in the undifferentiated state. Those ciPSC colonies exhibiting basic fibroblast growth factor (bFGF)-dependent proliferation were dissociated into single cells for passaging, and were maintained on a Matrigel-coated dish without feeder cells in a serum-free medium. The established ciPSCs had the ability to differentiate into three germ layers, via formation of embryoid bodies, as well as into cells expressing the same markers as mesenchymal stem cells. These ciPSCs may thus serve as a suitable source of pluripotent stem cell lines for regenerative veterinary medicine, with fewer concerns of contamination from unknown animal components.

Case report of multiple pustules of the bilateral lower limbs caused by a granulocyte colony-stimulating factor-producing solid pseudopapillary tumour of the pancreas

Here we report a rare case of neutrophilic dermatoses related to a granulocyte colony-stimulating factor (G-CSF)-producing solid pseudopapillary tumour (SPT). The patient was a 39-year-old woman presenting with scattered pustules and crusts of the palms, heels and thighs and plaques of the bilateral lower legs. The skin biopsy revealed dense neutrophil infiltration in the epidermis to the dermis. A pancreatic head tumour was detected using computed tomography. A pathological examination of the resected specimen suggested an SPT. As the skin eruption promptly disappeared after SPT resection, we hypothesized that SPT secretes growth factors including epidermal growth factor (EGF) and G-CSF. The SPT cells stained positive for both EGF and G-CSF tumour cells. The serum levels of interleukin (IL)-6 and IL-10 and tumour necrosis factor-α were within normal limits before and after the SPT resection. In contrast, the serum IL-8, EGF and G-CSF levels decreased after the SPT resection. This is a rare case of neutrophilic dermatoses related to a G-CSF-producing SPT. The present case suggests that physicians should be aware that a G-CSF-producing tumour is a differential diagnosis to consider in patients with unusual aseptic pustulosis.