Tumor resident mesenchymal stromal cells endow naïve stromal cells with tumor-promoting properties.

Bone marrow mesenchymal stem/stromal cells (BM-MSCs) can infiltrate into tumors and subsequently evolve into tumor resident MSCs in tumor microenvironment. In this study, using a mouse lymphoma model, we showed that the lymphoma resident MSCs (L-MSCs) are able to confer tumor-promoting property to the naïve cocultured BM-MSCs. Examination of cytokines and chemokines showed that post exposure to L-MSCs, BM-MSCs acquired an expression profile that is similar to that in L-MSCs. In vivo, BM-MSCs educated by L-MSCs (BM-L-MSCs) possess a greatly enhanced ability in promoting lymphoma growth. Consistent with an elevated CCL-2 expression in BM-L-MSCs, the tumor-promoting effect of BM-L-MSCs largely depends on CCR2-mediated macrophage recruitment to tumor sites. We further showed that the transmission of tumor-promoting effect is partially mediated by soluble factors. Our findings thus revealed a novel reinforcing mechanism in the maintenance of tumor microenvironment.

Polymorphism of SREBP1 is associated with beef fatty acid composition in Simmental bulls.

The sterol regulatory element binding factor 1 gene (SREBP1) plays an important role in the biosynthesis of fatty acids and cholesterol, and in lipid metabolism. The objective of this study was to investigate the effect of genetic polymorphisms of SREBP1 on the fatty acid composition of muscle and carcass traits in Simmental bulls and Snow Dragon black cattle. The 84-bp insertion/deletion (indel) in intron 5 of the bovine SREBP1 gene was genotyped by polymerase chain reaction to investigate its associations with traits. The results showed that the 84-bp indel in intron 5 was significantly associated with palmitoleic acid (C16:1), stearic acid (C18:0), saturated fatty acids (SFA), triglycerides (TAG), and the C16 index in Simmental bulls (P < 0.05). Cattle with the LL genotype had higher palmitic acid (C16:1), triglycerides, and C16 index but lower stearic acid (C18:0) and SFA compared to those with the LS genotype (P < 0.05). In conclusion, the 84-bp indel of SREBP1 could be used as a genetic marker for selecting Simmental breeding stock for healthier fatty acid composition.

The adipocytokine resistin stimulates the production of proinflammatory cytokines TNF-α and IL-6 in pancreatic acinar cells via NF-κB activation.

BACKGROUND: Resistin, an adipocytokine secreted by fat tissues, has been associated with the inflammatory response, though its role in inflammation during acute pancreatitis (AP) remains unclear. OBJECTIVE: The proinflammatory response following acinar cell injury impacts pancreatitis severity, necessitating better understanding of functional consequences associated with pancreatic acinar cell resistin exposure and resultant effects on proinflammatory signaling. METHODS: Amylase-secreting rat pancreatic acinar AR42J cells were subjected to 1, 10, or 100 ng/ml recombinant rat resistin treatments. Cytotoxicity was evaluated by amylase secretion and lactate dehydrogenase (LDH) release. Tumor necrosis factor-alpha (TNF-α) and interleukin 6 (IL-6) mRNA and protein expressions were determined by real-time real time-PCR and enzyme-linked immunosorbent assay, respectively. Nuclear NF-κB p65 subunit protein level was measured by western blotting. RESULTS: Significantly increased amylase secretion and LDH release was observed in the 100 ng/ml resistin treatment (p<0.01). Both TNF-α and IL-6 protein expression levels increased in a concentration-dependent manner when treated with resistin. Pretreatment of resistin- treated AR42J cells with the NF-κB inhibitor PDTC, which decreases the NF-κB p65 subunit protein expression levels in the nuclei, produced significantly lower mRNA expression levels for both TNF-α and IL-6 compared with those produced by resistin-treated cells (p<0.01). CONCLUSIONS: Resistin exhibits some cytotoxic activity in rat pancreatic acinar AR42J cells and stimulates proinflammatory cytokine TNF-α and IL-6 production via NF-κB activation. Thus, overproduction of obesity-related circulating resistin and associated lowgrade inflammation may result in mild injury to pancreatic acini, increasing AP severity and risk.

Polymorphism of MyoD1 and Myf6 genes and associations with carcass and meat quality traits in beef cattle.

Myogenic determination factor 1 (MyoD1) and myogenic factor 6 (Myf6) genes belong to the myogenic differentiation (MyoD) gene family, which play key roles in growth and muscle development. The study aimed to investigate the effects of variants in cattle MyoD1 and Myf6 on carcass and meat traits. We screened single nucleotide polymorphisms (SNPs) of both genes in 8 cattle populations, including Simmental, Angus, Hereford, Charolais, Limousin, Qinchuan, Luxi, and Jinnan by sequencing. The G782A locus was identified in exon 1 of MyoD1 (MyoD1-BglI) as well as the T186C locus in exon 1 of Myf6 (Myf6-ApaLI). For the two SNPs, the A allele was significantly more frequent than the B allele in the populations tested. The χ(2) test showed that the MyoD1-BglI locus conformed to Hardy-Weinberg equilibrium in the 8 populations, as did the Myf6-ApaLI locus, with the exception of the Simmental population (P > 0.05). Association analysis revealed that the MyoD1-BglI locus was significantly associated with loin muscle area (LMA) (P < 0.05), and the Myf6-ApaLI locus was significantly associated with carcass length (CL) (P < 0.05). Animals with BB and AB genotypes for the MyoD1-BglI locus had larger LMAs compared to animals with AA genotype. Individuals with BB genotype had longer CLs compared to those with AA and AB genotypes. We conclude that the two SNPs might provide useful genetic markers, opening up new possibilities for cattle breeding and improvements in gene-assisted selection.

Linkage Disequilibrium Estimation of Chinese Beef Simmental Cattle Using High-density SNP Panels.

Linkage disequilibrium (LD) plays an important role in genomic selection and mapping quantitative trait loci (QTL). In this study, the pattern of LD and effective population size (Ne ) were investigated in Chinese beef Simmental cattle. A total of 640 bulls were genotyped with IlluminaBovinSNP50BeadChip and IlluminaBovinHDBeadChip. We estimated LD for each autosomal chromosome at the distance between two random SNPs of <0 to 25 kb, 25 to 50 kb, 50 to 100 kb, 100 to 500 kb, 0.5 to 1 Mb, 1 to 5 Mb and 5 to 10 Mb. The mean values of r(2) were 0.30, 0.16 and 0.08, when the separation between SNPs ranged from 0 to 25 kb to 50 to 100 kb and then to 0.5 to 1 Mb, respectively. The LD estimates decreased as the distance increased in SNP pairs, and increased with the increase of minor allelic frequency (MAF) and with the decrease of sample sizes. Estimates of effective population size for Chinese beef Simmental cattle decreased in the past generations and Ne was 73 at five generations ago.

Mesenchymal stem cells: a double-edged sword in regulating immune responses.

Mesenchymal stem cells (MSCs) have been employed successfully to treat various immune disorders in animal models and clinical settings. Our previous studies have shown that MSCs can become highly immunosuppressive upon stimulation by inflammatory cytokines, an effect exerted through the concerted action of chemokines and nitric oxide (NO). Here, we show that MSCs can also enhance immune responses. This immune-promoting effect occurred when proinflammatory cytokines were inadequate to elicit sufficient NO production. When inducible nitric oxide synthase (iNOS) production was inhibited or genetically ablated, MSCs strongly enhance T-cell proliferation in vitro and the delayed-type hypersensitivity response in vivo. Furthermore, iNOS(-/-) MSCs significantly inhibited melanoma growth. It is likely that in the absence of NO, chemokines act to promote immune responses. Indeed, in CCR5(-/-)CXCR3(-/-) mice, the immune-promoting effect of iNOS(-/-) MSCs is greatly diminished. Thus, NO acts as a switch in MSC-mediated immunomodulation. More importantly, the dual effect on immune reactions was also observed in human MSCs, in which indoleamine 2,3-dioxygenase (IDO) acts as a switch. This study provides novel information about the pathophysiological roles of MSCs.

Establishment of a subcutaneous model of the human extrahepatic bile duct carcinoma in nude mice via transplantation of histologically intact tumor tissue.

The purpose of the study was to establish the subcutaneous model of human extrahepatic bile duct carcinoma in nude mice so as to provide a suitable model for the study of extrahepatic bile duct carcinoma. Surgical specimens of the patient with extrahepatic bile duct carcinoma were transplanted into the subcutaneous layer of nude mice. Growth curve of transplanted tumors was drawn and its morphological and biological characteristics, as well as choromosome were observed. A well differentiated mucinous adenocarcinoma model of human bile duct carcinoma in nude mice, designated as HBDCM1-ZSH (Human Bile Duct Carcinoma Model No. 1 established by Zhong Shan Hospital in April, 2001), was established via subcutaneous transplantation of the surgically resected tumor from a 56-year-old Chinese man. HBDCM1-ZSH has been maintained for 13 passages and exhibited 98.1% transplantability. Mean latent periods were 26 days. Transplanted tumors exhibited the characteristics of the original tumor in morphology and biology. Chromosomal analysis revealed numerical abnormalities ranging from 67 to 84. HBDCM1-ZSH expressed carcinoembryonic antigen (CEA), carbohydrate antigen (CA)19-9, cytokeratin (CK7, CK19, CK20), PCNA, AB and PAS. In conclusion, HBDCM1-ZSH is similar to human extrahepatic bile duct carcinoma and provides an applicable animal model for research on extrahepatic bile duct carcinoma.

The DSL domain in mutant JAG1 ligand is essential for the severity of the liver defect in Alagille syndrome.

Alagille syndrome (AGS) is a congenital multi-system anomaly mainly characterized by paucity of intrahepatic bile ducts caused by haploinsufficiency of the Jagged 1 gene (JAG1). To explore the relationship between genotype and phenotype, we analyzed the JAG1 gene in 25 Japanese AGS families at the genomic DNA level and identified 15 point mutations and one large deletion. Analysis of the genotype and phenotype strongly indicated that the Delta/Serrate/Lag-2 (DSL) domain in JAG1 protein played an essential role in determining the severity of the liver disorder. In four sporadic cases, missing an entire DSL domain in mutant JAG1 resulted in progressive liver failure and all 4 patients needed a liver transplant at a very young age. This correlation was further confirmed by statistical analysis (chi2=9.143, p<0.001). Our finding demonstrated that the DSL domain in JAG1 appears to be essential for normal liver development and function.

Mutational analysis of the Jagged 1 gene in Alagille syndrome families.

Alagille syndrome (AGS) is an autosomal dominant disease characterized by five major abnormalities in the liver, heart, face, vertebrae and eye. The responsible gene has been recently identified as the human Jagged 1 (JAG1) gene, which encodes a ligand for the Notch receptor. We analyzed the JAG1 gene in eight AGS families, including affected and unaffected individuals, at the genomic DNA level, mainly by single-strand conformational polymorphism (SSCP) and DNA sequencing analysis. Four categories of mutations were identified: (i) four frameshift mutations in exons 9, 22, 24 and 26 were exhibited respectively in affected individuals of four AGS families, which resulted in moving the translational frame of JAG1; (ii) one nonsense mutation, a 1 bp substitution in exon 5 of the EGF-like repeat domain, was detected in two unrelated AGS families, which altered codon 235 from arginine to stop; (iii) one acceptor splice site mutation of exon 5 was revealed in a sporadic patient; and (iv) a 1.3 Mb deletion, which included the entire JAG1 gene, was found in another patient. Our results further demonstrate that AGS is a dominant disease and suggest that the JAG1 gene exerts a fundamental role in regulating genes involved in development.

Linkage analysis and identification of deletion in Alagille syndrome gene.

Alagille syndrome (AGS) is a genetic disease and the responsible gene has already been mapped at 20p12. To more accurately detect the region of the AGS gene on the linkage map of chromosome 20p, 14 yeast artificial chromosome (YAC) clones were screened to construct a YAC contig in the candidate region and 13 locus markers and 2 sequence-tagged sites (STS) were ordered. Combining all of the analyses, a 1.3 Mb critical region from D20S507 to D20S61 for the AGS gene was identified. As the human Jagged 1 gene (JAG1) lies just in this region and is responsible for the AGS disease, the genomic DNA in an AGS family without a visible deletion were analyzed by single-strand conformational polymorphism (SSCP) and direct DNA sequencing, and a 2-bp (CT) deletion mutation at exon 26 of the JAG1 was identified.

[Effect of processing on the alkaloids in Strychnos nux-vomica L].

The contents of strychnine, brucine, isostrychnine and isobrucine in different processed products of Strychnos nux-vomica were determined by TLC-densitometry. The relationship of the contents of strychnos alkaloids with processing methods was studied.