Masaki Michishita

Comparison of bone marrow and adipose tissue-derived canine mesenchymal stem cells

BackgroundBone marrow-derived mesenchymal stem cells (BM-MSCs) and adipose tissue-derived mesenchymal stem cells (AT-MSCs) are potential cellular sources of therapeutic stem cells. MSCs are a multipotent population of cells capable of differentiating into a number of mesodermal lineages. Treatment using MSCs appears to be a helpful approach for structural restoration in regenerative medicine. Correct identification of these cells is necessary, but there is inadequate information on the MSC profile of cell surface markers and mRNA expression in dogs. In this study, we performed molecular characterization of canine BM-MSCs and AT-MSCs using immunological and mRNA expression analysis.ResultsSamples were confirmed to be multipotent based on their osteogenic and adipogenic differentiation. And these cells were checked as stem cell, hematopoietic and embryonic stem cell (ESC) markers by flow cytometry. BM- and AT-MSCs showed high expression of CD29 and CD44, moderate expression of CD90, and were negative for CD34, CD45, SSEA-3, SSEA-4, TRA-1-60, and TRA-1-81. SSEA-1 was expressed at very low levels in AT-MSCs. Quantitative real-time PCR (qRT-PCR) revealed expression of Oct3/4, Sox2, and Nanog in BM- and AT-MSCs. There was no significant difference in expression of Oct3/4 and Sox2 between BM-MSCs and AT-MSCs. However, Nanog expression was 2.5-fold higher in AT-MSCs than in BM-MSCs. Using immunocytochemical analysis, Oct3/4 and Sox2 proteins were observed in BM- and AT-MSCs.ConclusionOur results provide fundamental information to enable for more reproducible and reliable quality control in the identification of canine BM-MSCs and AT-MSCs by protein and mRNA expression analysis.

EP2 and EP4 receptors on muscularis resident macrophages mediate LPS-induced intestinal dysmotility via iNOS upregulation through cAMP/ERK signals

Intestinal resident macrophages play an important role in gastrointestinal dysmotility by producing prostaglandins (PGs) and nitric oxide (NO) in inflammatory conditions. The causal correlation between PGs and NO in gastrointestinal inflammation has not been elucidated. In this study, we examined the possible role of PGE2 in the LPS-inducible inducible NO synthase (iNOS) gene expression in murine distal ileal tissue and macrophages. Treatment of ileal tissue with LPS increased the iNOS and cyclooxygenase (COX)-2 gene expression, which lead to intestinal dysmotility. However, LPS did not induce the expression of iNOS and COX-2 in tissue from macrophage colony-stimulating factor-deficient op/op mice, indicating that these genes are expressed in intestinal resident macrophages. iNOS and COX-2 protein were also expressed in dextran-phagocytized macrophages in the muscle layer. CAY10404, a COX-2 inhibitor, diminished LPS-dependent iNOS gene upregulation in wild-type mouse ileal tissue and also in RAW264.7 macrophages, indicating that PGs upregulate iNOS gene expression. EP2 and EP4 agonists upregulated iNOS gene expression in ileal tissue and isolated resident macrophages. iNOS mRNA induction mediated by LPS was decreased in the ileum isolated from EP2 or EP4 knockout mice. In addition, LPS failed to decrease the motility of EP2 and EP4 knockout mice ileum. EP2- or EP4-mediated iNOS expression was attenuated by KT-5720, a PKA inhibitor and PD-98059, an ERK inhibitor. Forskolin or dibutyryl-cAMP mimics upregulation of iNOS gene expression in macrophages. In conclusion, COX-2-derived PGE2 induces iNOS expression through cAMP/ERK pathways by activating EP2 and EP4 receptors in muscularis macrophages. NO produced in muscularis macrophages induces dysmotility during gastrointestinal inflammation.

Aldehyde dehydrogenase activity in cancer stem cells from canine mammary carcinoma cell lines.

Increasing evidence suggests that diverse solid tumours arise from a small population of cells known as cancer stem cells or tumour-initiating cells. Cancer stem cells in several solid tumours are enriched for aldehyde dehydrogenase (ALDH) activity. High levels of ALDH activity (ALDH(high)) were detected in four cell lines derived from canine mammary carcinomas. ALDH(high) cells were enriched in a CD44(+)CD24(-) population having self-renewal capacity. Xenotransplantation into immunodeficient mice demonstrated that 1×10(4) ALDH(high) cells were sufficient for tumour formation in all injected mice, whereas 1×10(4) ALDH(low) cells failed to initiate any tumours. ALDH(high)-derived tumours contained both ALDH(+) and ALDH(-) cells, indicating that these cells had cancer stem cell-like properties.

Identification of tumor-initiating cells in a canine hepatocellular carcinoma cell line

Tumor-initiating cells (TICs) or cancer stem cells (CSCs), a small subset of tumor cells, are involved in tumor initiation, progression, recurrence and metastasis. In human hepatocellular carcinoma (HCC), TICs are enriched with cell surface markers and have the ability to self-renew and differentiate tumors at a high frequency. We established a canine HCC cell line, HCC930599, and analyzed it for stem and progenitor cell marker expression using flow cytometry. HCC930599 showed high CD44 and CD29, moderate CD90, and low CD133, CD34, CD24, CD117, and CD13 expression. CD90(+)CD44(+) and CD90(-)CD44(+) cells were characterized using the in vitro sphere assay and an in vivo transplant model. CD90(+)CD44(+) cells acquired enhanced self-renewal capacity, proliferative activity and tumourigenicity compared with CD90(-)CD44(+) cells, suggesting that TICs exist in the HCC930599 cell line and that CD90 is a marker for enriched TICs. Understanding TIC characteristics may help elucidate hepatic carcinogenesis and HCC therapy development.

Acinar Cell Cystadenoma of the Pancreas in a Cat

Cystic tumours of the pancreas are heterogeneous lesions with a spectrum of morphology and biological behaviour in people. These are poorly characterized in animals. A multicystic tumour of the pancreas was identified in an 11-year-old, female, mixed breed cat. The tumour was 5.5 cm in diameter and the largest cysts were 1.5 cm in diameter. Microscopically, the cysts were lined by single layered or pseudostratified, flat, cuboidal or columnar epithelial cells that occasionally formed papillary structures with a thin fibrous core. The tumour cells had eosinophilic granules in the apical cytoplasm, similar to zymogen granules, and the nuclei were uniform in size and shape. Mitotic figures were not observed. Immunohistochemically, the tumour cells expressed trypsin, but not cytokeratin 7. A diagnosis of acinar cell cystadenoma of the pancreas was made and this is the first report of this tumour in a cat.

Molecular cloning and tumour suppressor function analysis of canine REIC/Dkk-3 in mammary gland tumours

REIC/Dkk-3, a member of the human Dickkopf (Dkk) family, plays a role as a suppressor of growth in several human cancers. In this study, the tumour suppression function of canine REIC/Dkk-3 was investigated. The full-length open reading frame of the canine REIC/Dkk-3 homologue was cloned and the tissue distribution of REIC/Dkk-3 mRNA was determined, along with the subcellular localisation of the REIC/Dkk-3 protein in canine cancer cell lines. Expression of REIC/Dkk-3 was lower in mammary gland tumours and in canine mammary carcinoma cell lines than in normal mammary gland tissue. Overexpression of REIC/Dkk-3 induced apoptosis in canine mammary carcinoma cell lines. These results show that expression of REIC/Dkk-3 is downregulated in canine mammary tumours and that one of the functions of this gene is induction of apoptosis.

Mechanism of insulin production in canine bone marrow derived mesenchymal stem cells

Insulin is a critical hormone in the regulation of blood glucose levels and is produced exclusively by pancreatic islet beta-cells. Insulin deficiency due to reduced pancreatic islet beta-cell number underlies the progression of diabetes mellitus, prompting efforts to develop beta-cell replacement therapies. However, precise information on beta-cell replacement and differentiation in canines is limited. In this study, we established insulin-producing cells from bone marrow derived mesenchymal stem cells transiently expressing canine pancreatic and duodenal homeobox 1 (Pdx1), beta cell transactivator 2 (Beta2) and V-maf avian musculoaponeurotic fibrosarcoma oncogene homolog A (Mafa) using a gene transfer technique. Real-time PCR analysis revealed an increase in insulin mRNA expression of transfected cells. And ELISA revealed that insulin protein expressed was detected in cytoplasmic fraction. Insulin immunostaining analysis was performed and observed in cytoplasmic fraction. These results suggest that co-transfection of Pdx1, Beta2 and Mafa induce insulin production in canine BMSCs. Our findings provide a clue to basic research into the mechanisms underlying insulin production in the canines.

Amputation for histiocytic sarcoma in a cat

A 9-year-old spayed female domestic shorthair cat presented with a skin lesion of the left tarsus. The lesion was biopsied and, based on the microscopic appearance and immunohistochemical characteristics, histiocytic sarcoma was diagnosed. Amputation was performed with improved demeanor seen postoperatively. However, between 44 and 60 days following the surgery, relapse of skin lesions appeared in multiple locations, including at the previous amputation site, and euthanasia was elected. This is the first report of a histiocytic sarcoma treated with amputation in a cat.

Allogenic Adipose Tissue-Derived Mesenchymal Stem Cells Ameliorate Acute Hepatic Injury in Dogs

Adipose tissue-derived mesenchymal stem cells (AT-MSCs) are an attractive source for cell-based therapy of some diseases, including acute and chronic liver failure, in not only human medicine but also veterinary medicine. However, in veterinary medicine, no studies have reported the effects of AT-MSCs on liver injury in dogs. The purpose of this study was to investigate the effects of allogenic AT-MSCs on acute liver injury by carbon tetrachloride in dogs and to compare the therapeutic effects of AT-MSCs transplanted via the peripheral vein (PV) or splenic vein (SV). After transplantation of AT-MSCs through the PV or SV, serum liver enzymes were decreased significantly, and SV injection was more effective compared with PV injection. By comparing the number of engrafted AT-MSCs in the liver, SV injection was significantly more effective than PV injection. mRNA expression levels of proinflammatory cytokines, such as IL-1, IL-6, IL-8, and IFNγ, in the liver were decreased significantly, but those of anti-inflammatory cytokines, such as IL-4 and IL-10, HGF, and VEGFA, were significantly increased after the first AT-MSC injection. These findings suggest that allogenic AT-MSCs injected via the PV or SV ameliorate acute hepatic injury in dogs, and AT-MSCs injected via the SV provide more effective improvement.

Apocrine Sweat Gland Ductal Adenoma with Sebaceous Differentiation in a Dog

A 7-year-old male, Border Collie, developed a firm mass, measuring approximately 1u2009cm in diameter, in the left buccal skin. Histologically, the mass was composed of ductal structures lined by bilayered luminal epithelial and basaloid tumor cells along with a few nests of sebaceous cells. Immunohistochemical staining revealed that the luminal epithelial tumor cells were positive for cytokeratin (CK, CAM5.2) and CK19 but not for CK14 or p63. In contrast, the basaloid tumor cells were positive for CK14, p63, and αSMA but not for CK19 or CAM5.2. CK8 expression was observed in both luminal epithelial and basaloid tumor cells. The tumor cells with sebaceous differentiation were positive for CK14 but not for the other markers. This is the first case of an apocrine sweat gland ductal adenoma with sebaceous differentiation occurring in the buccal skin of a dog.