Dietary hydrolyzed soya lecithin affects feed intake, abundance of bacteria in the caecum, fatty acid composition and area of adipocytes in pre-mating primiparous V-line female rabbit

This study aimed at investigating the effect of hydrolyzed soya lecithin; also called lysolecithin or lysophosphatidylcholine, on growth performance, caecal microbiota and fat depots in pre-breeding primiparous rabbits does. For this, 60 V-Line primiparous rabbits does (5-6 months) were used in a 30-day experiment. Does were allotted into three iso-nitrogenous iso-caloric dietary treatments (n = 20/group) as follows: (1) CON received 0% soya lecithin, (2) LECL group was fed a basal diet supplemented with 0.5% soya lecithin and (3) LECH group was fed a basal diet supplemented with 1% soya lecithin. Growth performance indices were measured, caecum samples were collected for measurement of specific bacteria via qPCR, and several fat depots including periovarian fat were sampled for adipocyte morphometry and fatty acid profiling. Statistical analysis was performed using GLM procedures of SAS v9.4. Soya lecithin increased feed intake (p < 0.05). The abundance of caecal Bifidobacteria species, Ruminococcus species and phylum Butryvibrio-specific genes increased (p < 0.05) in rabbits receiving soya lecithin in their diet, soya lecithin increased the level of polyunsaturated fatty acids in subcutaneous and perirenal fat (p < 0.05) and increased the level of monounsaturated fatty acids in periovarian fat (p < 0.05); additionally, the adipocyte area increased in periovarian and perirenal fat (p < 0.05). In conclusion, soya lecithin at a dose of 0.5% increased feed intake and energy storage in adipocytes and improved the fatty acid profile of periovarian fat.

Azolla leaf meal at 5% of the diet improves growth performance, intestinal morphology and p70S6K1 activation, and affects cecal microbiota in broiler chicken

With growing concern about including unconventional dietary protein sources in poultry diets to substitute the protein sources that are essential for human consumption such as soybean meal, Azolla leaf meal (ALM) has grown in popularity. In our prior experiment, ALM was used at inclusion rates of 5 and 10%. Five per cent inclusion of ALM increased broiler chicken growth performance, the concentration of cecal propionic acid, and activation of skeletal muscle p70S6 Kinase1 (p70S6K1) without having detrimental effects on the meat quality. Those results prompted us to further evaluate the effect of the same inclusion rates of ALM on phase feeding and intestine and liver health of the broiler chicks. The current study hypothesis is that dietary ALM positively affects phase feeding, intestinal morphology and p70S6K1 activation, cecal microbial gene expression, and improves the liver energy status. For this, we enrolled 135 one-day-old broiler chicks and collected growth performance data (starter, grower, and finisher stages) and samples of the gastrointestinal tract to analyse the morphology of the villi, immune-related organs, mucin, and abundance of intestinal p70S6K1. Cecal bacterial species were analysed using qPCR and liver samples were collected to analyse adenosine monophosphate (AMP) and ATP content and selected oxidative stress biomarkers. ALM increased BW and feed intake during the starter and grower phases but did not affect the feed conversion ratio. Liver oxidative stress and AMP: ATP ratio increased in chickens fed on a diet containing 10% ALM (AZ10; P < 0.05). Jejunum villi length and abundance of duodenal neutral mucin increased but villi of the ileum decreased in chickens fed on a diet containing 5% ALM (AZ5), while lymphoid follicle areas of the cecal tonsils decreased with both doses of ALM. Activation of p70S6K1 increased with AZ10 in the duodenum and AZ5 in the jejunum. In the gut, the family of Enterobacteriaceae decreased with both ALM doses. In conclusion, our results indicate an overall positive effect of dietary inclusion of ALM in the broiler chicken diet via its positive effect on intestinal morphology and function; however, a negative effect on the liver was observed with 10% ALM.

Sun-dried Azolla leaf meal at 10% dietary inclusion improved growth, meat quality, and increased skeletal muscle Ribosomal protein S6 kinase β1 abundance in growing rabbit

Rapidly growing human populations and the increased need for high nutritive value meat in terms of low fat, high protein, and low sodium content are the driving reasons for the increase in rabbit meat production. However, dietary protein alternatives to sustain rabbit meat production, without competing with humans for strategic crops are needed. Therefore, the current study was conducted to investigate the effect of Azolla leaf meal (ALM) as a dietary protein source on growth performance, meat quality, and abundance and activation of Ribosomal protein S6 kinase β1 (p70S6K1), a downstream target of mammalian target of rapamycin signalling pathway and, thus, a key player in the regulation of protein synthesis and muscle mass. For this purpose, 60 weaned male V-Line rabbits were blocked for the initial BW and randomly allotted into four dietary treatments, with 15 replicate per treatment (n = 15/group) as follows: (1) CON group was fed on basal diet contains 0% of ALM, (2) AZ10 group fed on diet containing 10% ALM, (3) AZ20 group fed on diet containing 20% ALM, and (4) AZ30 group fed on diet containing 30% ALM. Rabbits were raised individually, and the experimental period was 42 days. At the end of the experiment, rabbits were euthanised and blood and skeletal muscle samples were collected. Body weight and BW gain were the highest in AZ10 group (P = 0.01), while feed intake was the highest in AZ30 (P = 0.01), feed conversion ratio was the lowest in AZ10 and highest in AZ30 (P = 0.01). Dressing % was the highest in AZ10 and lowest in AZ30 groups (P = 0.01). Muscle cross-sectional area was low in both AZ20 and AZ30 groups compared to CON (P = 0.01). The lysine concentration of Longissimus lumborum muscle increased (P = 0.03) while isoleucine tended to decrease in AZ10 vs CON (P = 0.09). The phosphorylation ratio of skeletal muscle p70S6K1 increased in AZ10 and AZ20 groups (P = 0.05). Therefore, ALM could be included in a growing rabbit diet, up to 10%, while higher doses negatively alter production performance, meat quality, and feed efficiency of growing rabbits.

Hepatic transcriptomic adaptation from prepartum to postpartum in dairy cows

The transition from pregnancy to lactation is the most challenging period for high-producing dairy cows. The liver plays a key role in biological adaptation during the peripartum. Prior works have demonstrated that hepatic glucose synthesis, cholesterol metabolism, lipogenesis, and inflammatory response are increased or activated during the peripartum in dairy cows; however, those works were limited by a low number of animals used or by the use of microarray technology, or both. To overcome such limitations, an RNA sequencing analysis was performed on liver biopsies from 20 Holstein cows at 7 ± 5d before (Pre-P) and 16 ± 2d after calving (Post-P). We found 1,475 upregulated and 1,199 downregulated differently expressed genes (DEG) with a false discovery rate adjusted P-value < 0.01 between Pre-P and Post-P. Bioinformatic analysis revealed an activation of the metabolism, especially lipid, glucose, and amino acid metabolism, with increased importance of the mitochondria and a key role of several signaling pathways, chiefly peroxisome proliferators-activated receptor (PPAR) and adipocytokines signaling. Fatty acid oxidation and gluconeogenesis, with a likely increase in amino acid utilization to produce glucose, were among the most important functions revealed by the transcriptomic adaptation to lactation in the liver. Although gluconeogenesis was induced, data indicated decrease in expression of glucose transporters. The analysis also revealed high activation of cell proliferation but inhibition of xenobiotic metabolism, likely due to the liver response to inflammatory-like conditions. Co-expression network analysis disclosed a tight connection and coordination among genes driving biological processes associated with protein synthesis, energy and lipid metabolism, and cell proliferation. Our data confirmed the importance of metabolic adaptation to lipid and glucose metabolism in the liver of early Post-P cows, with a pivotal role of PPAR and adipocytokines.

Short communication: Molecular markers for epithelial cells across gastrointestinal tissues and fecal RNA in preweaning dairy calves

The objective of this study was to compare the transcription of gene markers for gastrointestinal (GI) epithelial cells, including fatty acid binding protein 2 (FABP2) and cytokeratin 8 (KRT8), and tight junction complex genes (TJP1, CLDN1, CLDN4) in fecal RNA against several GI tract tissue sections in dairy calves. Eight healthy Jersey calves were euthanized at 5 wk of age, and postmortem samples were collected from rumen, duodenum, jejunum, ileum, large intestine, cecum, and feces for total RNA isolation. Tissues and fecal samples were immediately frozen in liquid nitrogen until RNA isolation. A real-time quantitative PCR analysis was performed using a single standard curve composited of equal amounts of all samples, including cDNA from fecal and GI tract tissues. The mRNA expression of the tight junctions TJP1, CLDN1, and CLDN4 was greater in fecal RNA compared with lower GI tract tissues (i.e., duodenum, jejunum, ileum, large intestine, and cecum). Similar to fecal RNA, rumen tissue had greater expression of tight junctions CLDN1 and CLDN4 than lower GI tract tissues. Similarly, rumen tissue had greater expression of TPJ1 than all lower GI tract tissues except duodenum. The expression of TJP1 and CLDN4 was greater in fecal RNA than in rumen tissue; in contrast, CLDN1 mRNA expression was greater in rumen tissue than in the fecal RNA. The expression of FABP2 was greater in duodenum in comparison to all tissue except ileum. The mRNA expression of FABP2 in fecal samples was similar to jejunum and ileum. The expression of KRT8 in fecal samples was similar to duodenum, large intestine, and cecum. The fecal RNA had a greater expression of KRT8 in comparison to jejunum and ileum. The rumen tissue had the lowest mRNA expression of KRT8. The expression levels of FABP2, KRT8, and tight junction genes observed in fecal transcripts suggest that a considerable amount of RNA derived from GI tract epithelial cells can be detected in fecal RNA, which is in agreement with previous data in neonatal dairy calves and other biological models including humans, rodents, and primates. The greater expression of tight junctions in fecal RNA in comparison to sections of the low GI remains to be understood, and due to the importance of tight junctions in GI physiology, further clarification of this effect is warranted. The similarities in mRNA expression of FABP2 and KRT8 between fecal RNA and intestinal sections add up to the accumulating evidence that fecal RNA can be used to investigate molecular alterations in the GI tract of neonatal dairy calves. Further research in this area should include high-throughput transcriptomic analysis via RNA-seq to uncover novel molecular markers for specific sections of the GI tract of neonates.

Long term conjugated linoleic acid supplementation modestly improved growth performance but induced testicular tissue apoptosis and reduced sperm quality in male rabbit

Conjugated linoleic acid (CLA) is known for its multiple benefits including improvement of growth, increasing lean mass, and anti-carcinogenic effects. However, when used in long-term supplementations CLA does not improve semen parameters in boar and bull and reduces fertility in Japanese quails. The content of unsaturated fatty acids in dietary lipids plays a significant role in spermatogenesis owning the high proportion of unsaturated fatty acids in plasma membrane of sperms. Whether CLA plays a role in testicular tissue and epididymal fat is still unknown. Therefore, in this study we hypothesize that long-term supplementation of equal proportion of CLA isomer mix (c9,t11-CLA and t10,c12- CLA) in rabbit bucks might alter male reproductive potentials. Twelve V-Line weaned male rabbits were used in 26 weeks trial, rabbits were individually raised and randomly allocated into three dietary groups. Control group (CON) received a basal diet, a group received 0.5% CLA (CLA 0.5%), and a group received 1% CLA (CLA 1%). Rabbits were euthanized at the end of the trial and several parameters were evaluated related to growth, semen quality, and testicular and epididymal tissue histopathology and transcriptome. The long-term supplementation of CLA increased feed intake by 5% and body weight by 2-3%. CLA 1% decreased sperm progressive motility. In testicular tissue L-carnitine and α-tocopherol were decreased by CLA supplementation. In epididymal fat, CLA tended to decrease concentration of polyunsaturated fatty acids, the expression of SCD5 gene was upregulated by CLA 1% and CASP3 gene was upregulated by CLA 0.5%. Transcription of PPARG was downregulated by CLA. Feeding 1% CLA also decreased testicular epithelial thickness. Long-term supplementation of CLA modestly enhanced male rabbit growth, but negatively impacted male reproduction, especially at high dose of CLA.

The role of altered immune function during the dry period in promoting the development of subclinical ketosis in early lactation

Subclinical ketosis (SCK) may impair white blood cell (WBC) function and thus contribute to the risk of disease postpartum. This preliminary study investigated changes occurring in the immune system before disease onset to elucidate their role in the occurrence of SCK. A group of 13 Holstein dairy cows were housed in tie-stalls and retrospectively divided into 2 groups based on their levels of β-hydroxybutyrate (BHB) measured in plasma between calving day and 35 d from calving (DFC). Levels of BHB <1.4 mmol/L were found in 7 cows (control cows, CTR group) and levels >1.4 mmol/L were found in 6 cows at ≥1 of 6 time points considered (cows with SCK, KET group). From -48 to 35 DFC, body condition score, body weight, dry matter intake, rumination time, and milk yield were measured, and blood samples were collected regularly to assess the hematochemical profile and test the WBC function by ex vivo challenge assays. Data were submitted for ANOVA testing using a mixed model for repeated measurements that included health status and time and their interactions as fixed effects. Compared with CTR cows, KET cows had more pronounced activation of the immune system (higher plasma concentrations of proinflammatory cytokines, myeloperoxidase, and oxidant species, and greater IFN-γ responses to Mycobacterium avium), higher blood concentrations of γ-glutamyl transferase, and lower plasma concentrations of minerals before calving. Higher levels of nonesterified fatty acids, BHB, and glucose were detected in KET cows than in CTR cows during the dry period. The effect observed during the dry period was associated with a reduced dry matter intake, reduced plasma glucose, and increased fat mobilization (further increases in nonesterified fatty acids and BHB) during early lactation. A reduced milk yield was also detected in KET cows compared with CTR. The KET cows had an accentuated acute-phase response after calving (with greater concentrations of positive acute-phase proteins and lower concentrations of retinol than CTR cows) and impaired liver function (higher blood concentrations of glutamate-oxaloacetate transaminase and bilirubin). The WBC of the KET cows, compared with CTR cows, had a reduced response to an ex vivo stimulation assay, with lower production of proinflammatory cytokines and greater production of lactate. These alterations in the WBC could have been driven by the combined actions of metabolites related to the mobilization of lipids and the occurrence of a transient unresponsive state against stimulation aimed at preventing excessive inflammation. The associations identified here in a small number of cows in one herd should be investigated in larger studies.

Heat stress negatively affects the transcriptome related to overall metabolism and milk protein synthesis in mammary tissue of midlactating dairy cows

Inadequate dry matter intake only partially accounts for the decrease in milk protein synthesis during heat stress (HS) in dairy cows. Our hypothesis is that reduced milk protein synthesis during HS in dairy cows is also caused by biological changes within the mammary gland. The objective of this study was to assess the hypothesis via RNA-Seq analysis of mammary tissue. Herein, four dairy cows were used in a crossover design where HS was induced for 9 days in environmental chambers. There was a 30-day washout between periods. Mammary tissue was collected via biopsy at the end of each environmental period (HS or pair-fed and thermal neutral) for transcriptomic analysis. RNA-Seq analysis revealed HS affected >2,777 genes (false discovery rate-adjusted P value < 0.05) in mammary tissue. Expression of main milk protein-encoding genes and several key genes related to regulation of protein synthesis and amino acid and glucose transport were downregulated by HS. Bioinformatics analysis revealed an overall decrease of mammary tissue metabolic activity by HS (especially carbohydrate and lipid metabolism) and an increase in immune activation and inflammation. Network analysis revealed a major role of TNF, IFNG, S100A8, S100A9, and IGF-1 in inducing/controlling the inflammatory response, with a central role of NF-κB in the process of immunoactivation. The same analysis indicated an overall inhibition of PPARγ. Collectively, these data suggest HS directly controls milk protein synthesis via reducing the transcription of metabolic-related genes and increasing inflammation-related genes.

Activation of liver X receptor promotes fatty acid synthesis in goat mammary epithelial cells via modulation of SREBP1 expression

In bovine mammary tissue and cells, liver X receptor (LXR) regulates lipid synthesis mainly via transactivation of the transcription factor sterol regulatory element binding protein 1 (SREBP1). In the present work, we investigated the role of LXR in controlling lipid synthesis via transactivation of SREBP1 in goat primary mammary cells (GMEC). The GMEC were treated with a synthetic agonist of LXR, T0901317, and transactivation and transcription of SREBP1, expression of lipogenic genes, and fatty acid profiling and triacylglycerol (TAG) content of the cells were measured. A mild increase in the mRNA expression level of LXRα (NR1H3) was observed following treatment with different concentrations of T0901317, and a dose-dependent increase in mRNA and transactivation of SREBP1 was detected. Activation of LXR resulted in a significant increase in the mRNA expression of most of the measured genes related to de novo synthesis, desaturation, and transport of fatty acids; TAG synthesis; and transcription regulators. Compared with the control, total content of cellular TAG increased by more than 20% with T0901317 treatment. Furthermore, addition of T0901317 increased the proportion of unsaturated fatty acids (e.g., C16:1, C18:1, C20:1, and C22:1), and decreased the proportion of saturated fatty acids (e.g., C16:0, C18:0, C20:0, and C22:0). These results provide evidence that LXR regulates the expression and activity of SREBP1. Our results indicated that LXR participate in regulating the transcription of genes involved in milk fat synthesis in GMEC in an SREBP1-dependent fashion.

TRIENNIAL LACTATION SYMPOSIUM: Nutrigenomics in livestock: Systems biology meets nutrition

The advent of high-throughput technologies to study an animal's genome, proteome, and metabolome (i.e., "omics" tools) constituted a setback to the use of reductionism in livestock research. More recent development of "next-generation sequencing" tools was instrumental in allowing in-depth studies of the microbiome in the rumen and other sections of the gastrointestinal tract. Omics, along with bioinformatics, constitutes the foundation of modern systems biology, a field of study widely used in model organisms (e.g., rodents, yeast, humans) to enhance understanding of the complex biological interactions occurring within cells and tissues at the gene, protein, and metabolite level. Application of systems biology concepts is ideal for the study of interactions between nutrition and physiological state with tissue and cell metabolism and function during key life stages of livestock species, including the transition from pregnancy to lactation, in utero development, or postnatal growth. Modern bioinformatic tools capable of discerning functional outcomes and biologically meaningful networks complement the ever-increasing ability to generate large molecular, microbial, and metabolite data sets. Simultaneous visualization of the complex intertissue adaptations to physiological state and nutrition can now be discerned. Studies to understand the linkages between the microbiome and the absorptive epithelium using the integrative approach are emerging. We present examples of new knowledge generated through the application of functional analyses of transcriptomic, proteomic, and metabolomic data sets encompassing nutritional management of dairy cows, pigs, and poultry. Published work to date underscores that the integrative approach across and within tissues may prove useful for fine-tuning nutritional management of livestock. An important goal during this process is to uncover key molecular players involved in the organismal adaptations to nutrition.

The Impact of Intramammary Escherichia coli Challenge on Liver and Mammary Transcriptome and Cross-Talk in Dairy Cows during Early Lactation Using RNAseq

Our objective was to identify the biological response and the cross-talk between liver and mammary tissue after intramammary infection (IMI) with Escherichia coli (E. coli) using RNAseq technology. Sixteen cows were inoculated with live E. coli into one mammary quarter at ~4–6 weeks in lactation. For all cows, biopsies were performed at -144, 12 and 24 h relative to IMI in liver and at 24 h post-IMI in infected and non-infected (control) mammary quarters. For a subset of cows (n = 6), RNA was extracted from both liver and mammary tissue and sequenced using a 100 bp paired-end approach. Ingenuity Pathway Analysis and the Dynamic Impact Approach analysis of differentially expressed genes (overall effect False Discovery Rate≤0.05) indicated that IMI induced an overall activation of inflammation at 12 h post-IMI and a strong inhibition of metabolism, especially related to lipid, glucose, and xenobiotics at 24 h post-IMI in liver. The data indicated in mammary tissue an overall induction of inflammatory response with little effect on metabolism at 24 h post-IMI. We identified a large number of up-stream regulators potentially involved in the response to IMI in both tissues but a relatively small core network of transcription factors controlling the response to IMI for liver whereas a large network in mammary tissue. Transcriptomic results in liver and mammary tissue were supported by changes in inflammatory and metabolic mediators in blood and milk. The analysis of potential cross-talk between the two tissues during IMI uncovered a large communication from the mammary tissue to the liver to coordinate the inflammatory response but a relatively small communication from the liver to the mammary tissue. Our results indicate a strong induction of the inflammatory response in mammary tissue and impairment of liver metabolism 24h post-IMI partly driven by the signaling from infected mammary tissue.

Reducing milking frequency during nutrient restriction has no effect on the hepatic transcriptome of lactating dairy cattle

The objective of this study was to investigate if a reduced milking frequency altered the effect of dietary energy restriction on the hepatic transcriptome of grazing dairy cows during early lactation. Multiparous Holstein-Friesian and Holstein-Friesian × Jersey cows (n = 120) were milked twice daily (2×) from calving until 34 ± 6 days in milk (mean ± SD). Cows were then allocated to one of four treatments in a 2 × 2 factorial arrangement. Treatments consisted of two milking frequencies [2× or once daily (1×)] and two feeding levels for 3 wk: adequately fed (AF) or underfed (UF, 60% of AF). Liver tissue was biopsied from 12 cows per treatment after 3 wk of treatment, and the hepatic transcriptome was profiled with an Agilent 4 × 44k bovine microarray. Over 2,900 genes were differentially expressed in response to the energy restriction; however, no effects resulted from changes to milking frequency. This may indicate that after 3 wk of 1× milking, any changes to the liver transcriptome that may have occurred earlier have returned to normal. After 3 wk of energy restriction, gene expression patterns indicate that glucose-sparing pathways were activated, and gluconeogenesis was increased in UF cows. Genes involved in hepatic stress were upregulated in response to the energy restriction indicative of the pressure energy restriction places on liver function. Other pathways upregulated included "cytoskeletal remodeling," indicating that a 3 wk energy restriction resulted in molecular changes to assist tissue remodeling. Overall, 1× milking does not modify the hepatic transcriptome changes that occur in response to an energy restriction.

287 PORCINE ADIPOSE-DERIVED STEM CELLS IN CO-CULTURE FUSE ACTIVELY WITH MOUSE MYOTUBES AND EXPRESS MYOGENIC MARKERS

Mesenchymal stem cells (MSC) have been shown to be useful in regenerative medicine with their capability to give rise to various different cell types, including osteoblasts, adipocytes, chondrocytes, muscle cells, and neurons. Among MSC, bone marrow-derived stem cells (BMSC) are considered the primary source. Recently, many studies have shown the regenerative capabilities of adipose-derived stem cells (ASC). The ASC, with their greater abundance and ease of harvest, provide clear advantages over BMSC. We have previously demonstrated the myogenic differentiation of porcine ASC when co-cultured with differentiating C2C12 myoblasts in a myogenic differentiation-promoting medium. In this study, we sought to examine the myogenic potential of porcine ASC when co-cultured with fully differentiated murine myotubes. For the present study, we used porcine ASC isolated from the back fat of a transgenic gree fluorescent protein (GFP)-expressing pig at passage 3. The ASC were added to mouse C2C12 myotube cultures that had been induced towards myogenesis for 72 h. As controls, we co-cultured, in the same conditions, GFP-expressing endothelial cells (ENDO) from the aorta of the same pig. Additionally, we cultured ASC, ENDO, and C2C12 cells alone in myogenic-differentiation medium. Cultures were harvested at 12, 24, and 48 h after addition of porcine cells to myotube cultures for measurement of mouse- or porcine-specific myogenic markers by quantitative RT-PCR and immunohistochemistry. We were able to observe fusion of ASC GFP-expressing cells with pre-formed mouse myotubes by detection of myotubes expressing GFP. Additionally, immunofluorescent staining of co-cultures with an antibody specific for porcine nuclear Lamin A demonstrated the presence of ASC nuclei incorporated into myotubes. We observed large increases in gene expression of porcine-specific myogenin (MYOG; >900-fold) and desmin (DES; 8-fold). Unexpectedly, ENDO in co-culture with myotubes also had increased expression of DES (4-fold) and MYOG (400-fold), possibly indicating their de-differentiation and adaptation to a myogenic phenotype. In addition, expression of mouse-specific DES and MYOG were boosted in C2C12 myotubes when co-cultured for 48 h compared with C2C12 alone, suggesting enhanced myogenesis or prolonged survival of myotubes in co-culture. Cultures of ASC and ENDO alone did not display increased expression of myogenic markers. These results provide support for the use of ASC for muscle regeneration strategies, as in the case of damaged muscles and muscular dystrophy. In addition, compared with our previous observations, where ASC were co-cultured with undifferentiated C2C12, the ASC co-cultured with myotubes appeared to have an enhanced fusion and expression of myogenic markers. Finally, the capacity of ENDO to fuse and actively expressed muscle-specific genes deserves further investigation.

282 PORCINE ADIPOSE-DERIVED STEM CELLS ARE INDUCED TOWARD NEUROGENIC LINEAGES BY CELL-TO-CELL INTERACTIONS BUT NOT BY SOLUBLE FACTORS RELEASED BY NEURONS ISOLATED FROM ADULT AND FETAL BRAIN

Stroke, Parkinson’s, Alzheimer’s, and other neurological diseases that are relatively frequent in human involve loss of neurons. The advent of tissue regeneration using stem cells holds great promise in finding cures. In particular, mesenchymal stem cells (MSC) appear to be a very potent source for tissue regeneration. Among MSC subtypes, adipose-derived stem cells (ASC) have several distinct advantages. The ASC are abundant, are easy to isolate and expand in vitro, can be used for heterologous as well autologous transplants, and have multilineage differentiation capacity. In addition to osteocytes, chondrocytes, and adipocytes, the ASC have been successfully differentiated into neuronal-like cells by addition of specific neurogenic factors. However, in vivo differentiation of ASC into neurons remains to be demonstrated. In the present study, we used an in vitro system in order to evaluate whether ASC can be induced towards neurogenic lineages by physical contact with freshly isolated neurons or by factors released by neurons without addition of specific neurogenic factors. Experimentally, ASC and neurons (NEU) were extracted from the back fat or the brain, respectively, of a boar transgenic for green fluorescent protein (GFP) or from wild type pigs. The non-GFP neurons were isolated from the brain of 32-day fetuses or adult pigs. Cells were cultivated in 24-well plates with the following combinations: only ASC or NEU in DMEM (controls), ASC with conditioned medium from NEU, or ASC+NEU. Cells were harvested at 24 h and at 3, 7, 14, and 21 days and fixed with 4% paraformaldehyde in PBS for 15 min for immunohistochemistry analysis. After fixation, neuronal differentiation was evaluated by histological staining with specific neuronal markers. The proportion of ASC that differentiated into neuronal-like cells was determined using fluorescence microscopy. We observed little proliferation of ASC in conditioned medium compared with control ASC; however, a few cells exhibited neuronal-like morphology but with no expression of neuronal markers. When ASC were co-cultured with fetal NEU, starting at 3 days, we observed, using microscope analyses, that 4 to 12% of the ASC had neuronal-like morphology and expressed neuron-associated cell markers. When ASC were co-cultured with neurons from adult brain, we observed a lower fraction (between 1 and 2%) of neuronal differentiated cells starting at 7 days. Our data are preliminary but provide evidence that when ASC are in physical contact with neurons (i.e. by cell-to-cell interactions), they can be induced to differentiate into neuronal-like cells. Further, the differentiation is more rapid and extensive when the ASC are in direct contact with fetal neurons. However, further study is necessary to determine whether these neuronal-like cells are functional neurons. In this regard, we are performing electrophysiological analysis and measurement of expression of neuronal genes. In addition, flow cytometry will be used to quantify the proportion of differentiated ASC.

280 OSTEOGENIC ACTIVITY OF IN HOUSE-PRODUCED PORCINE BMP2 ON ADIPOSE-DERIVED STEM CELLS

In our laboratory, we extensively study the possibility of using adipose-derived stem cells (ASC) for maxillofacial bone regeneration. This includes also the tissue repair of large critical-size osteotomies requiring the use of tridimensional scaffolds. Bone regeneration in scaffolds can be greatly enhanced by the use of specific growth factors such as BMP2. In the present study, we compared the activity of commercially available human BMP2 (hBMP2) with in house-produced porcine BMP2 (pBMP2). The latter was synthesised using the BMP2 coding sequence from mRNA obtained from porcine ASC cell cultures. The coding sequence of the mature protein was cloned into a pET-21 plasmid and produced in E. coli as inclusion bodies. The activity of pBMP2 and hBMP2 was tested on ASC isolated from male pigs at passage 4 and at approximately 80% confluence in 48-well plates. Cells were treated in triplicate with hBMP2 or pBMP2 at 0.5, 5, 50, 500, or 1000 ng mL–1, adipogenic medium (AM), osteogenic medium (OM), or normal DMEM medium supplemented with acetic acid (used to resuspend BMP2 as the control) for 5 or 17 days. Cells were harvested for Alizarin Red S (AR) quantification and expression of osteogenic genes. For the AR analysis, cells were fixed with formalin and treated with AR. The AR was then extracted by acetic acid and neutralized with ammonium hydroxide before spectrophotometer reading at an absorbance of 420 nm. Data were analysed using GLM of SAS (SAS Institute Inc., Cary, NC, USA) with treatment, time, concentration, and all interactions as main effects. Using an inverted robotic stage microscope, images of the entire well for each replicate were taken every 2 to 3 days. Images revealed formation of osteogenic nodules in OM and characteristic large cells filled with lipid droplets in AM. No evident nodule formation was observed in the other treated cells at any time point. The AR was higher than control in both hBMP2 and pBMP2 at 0.5, 50, and 1000 ng mL–1 but not at 5 and 500 ng mL–1. There was no overall difference between hBMP2 and pBMP2 but the former had the highest AR value at 5 days in cells treated with 0.5 ng mL–1 and pBMP2 at 17 days with 1000 ng mL–1. Interestingly, both had higher values compared to OM, particularly at 5 days. We also observed an increase of AR due to time in cells treated with acetic acid (control). Overall, the data appear to indicate an increase in calcium accumulation in cells treated with both hBMP2 and pBMP2, with an early increase in the former and a late and larger increase in the latter. This might indicate a larger but slower activity of pBMP2 compared with hBMP2. The lack of formation of osteogenic nodules by both BMP2 might indicate an insufficiency of BMP2 to induce osteogenesis in porcine ASC. This last observation, together with the lack of increased AR accumulation compared with control at the 5 and 50 ng mL–1 doses, suggests the need for a more accurate analysis of BMP2 activity by measuring expression of BMP2-related genes. Finally, the data provide preliminary support for the equivalency of activity of pBMP2 and hBMP2 for in vivo bone regeneration.

291 THE USE OF THE DYNAMIC IMPACT APPROACH AND DESORPTION ELECTROSPRAY IONIZATION - MASS SPECTROSCOPY TO ANALYZE ADIPOGENESIS IN PORCINE ADIPOSE-DERIVED STEM CELLS

The measurement of end products of metabolism in combination with the dynamic measurement of the transcriptome can be a valuable approach to study complex processes, such as adipogenesis. For this purpose, we have combined the analysis of metabolic pathways using transcriptomics data with in situ lipid imaging obtained by desorption electrospray ionization–mass spectroscopy (DESI-MS). The transcriptome data was obtained from a previous experiment where adipose-derived stem cells (ASC) from 3 individual pigs were induced to differentiate into adipocytes for 21 days. The metabolic pathway analysis of transcriptomics data was performed using the dynamic impact approach (DIA) to determine the directional impact of pathways and gene categories. For the DESI-MS, porcine ASC were induced towards adipogenic differentiation (Monaco et al. 2009 Open Tissue Eng. Regen. Med. J. 2, 20–33) for 2 weeks in 24-well plates over round coverslips. Direct lipid profile of fatty acids and phospholipids in 3 different locations in undifferentiated and differentiated ASC was performed. Relative values of ion counts in each location were used for statistical analysis by means of a two-tailed t-test with unequal variance and false discovery rate (FDR) correction. The DIA uncovered amino acid and lipid metabolism as being the most affected pathways during adipogenesis. Among lipid-related pathways, the DIA indicated a strong induction during differentiation of unsaturation of fatty acids (FA) and metabolism of lipids, particularly triacylglycerol formation (TAG). The metabolism of tryptophan, phenylalanine, and histidine was strongly induced among amino acid-related metabolism. Among the lipid molecules identified in the mass-to-charge ratio (m/z) range of 250–1000 by the DESI-MS, >200 had significantly (FDR <0.01) lower abundance and ~30 lipids had higher abundance in differentiated compared with undifferentiated ASC. The lipid profile of undifferentiated cells was featured by a large amount of lipid molecules in the lower (m/z 780) mass range but with almost no signal in the intermediate range. The differentiated cells had a consistent large increase in amount of molecules in the range from m/z 500 to 650 and a decreased amount in the lower and upper ranges. Among the lipid molecules that decreased during differentiation, we identified several phospholipids, particularly phosphoserine and phosphoinositol species, but also linoleic, linolenic, arachidic, and eicosapentaenoic acids. The unsaturated FA oleate and docosahexaenate increased >10-fold and 2.2-fold, respectively, due to adipogenic differentiation. High-resolution experiments are being performed in order to annotate more, if not all, lipid species identified in the samples by DESI-MS. The DIA indicated greater unsaturation of FA during adipogenesis, confirmed by DESI-MS, which corresponds to the characteristic increase in lipid fractions with intermediate molecular mass. This can be considered a signature of adipogenesis in porcine ASC and essential for TAG formation. The DESI-MS appears to be a valuable tool for rapid lipid profile of cells and with the potential to be used to identify cell differentiation.

213 TRANSCRIPTOMIC COMPARISON BETWEEN PORCINE ADIPOSE AND BONE MARROW MESENCHYMAL STEM CELLS DURING IN VITRO OSTEOGENIC AND ADIPOGENIC DIFFERENTIATION

Previous data support the use of adipose-derived stem cells (ASC) as an alternative to bone marrow as a source of adult stem cells for therapeutic purposes. The aims of the present study were to directly compare the transcriptome of ASC and bone marrow-derived mesenchymal stem cells (BMSC) in order to uncover potential functional differences between the two mesenchymal stem cells (MSC), to identify differentially expressed genes (DEG) and related functions that may drive MSC to become bone or adipose and to identify potential markers for adipogenic and osteogenic differentiation. ASC and BMSC, isolated from subcutaneous adipose tissue and femurs of 3 adult pigs were differentiated in vitro along the osteogenic and adipogenic lineage for up to 4 wk. At 0, 2, 7 and 21 days of differentiation, RNA was extracted for microarray analysis. Data were normalized by Lowess and statistical analysis run using ANOVA with Benjamini-Hochberg false discovery rate (FDR) correction. Data mining was carried out using Ingenuity Pathway Analysis and DAVID. Analysis of undifferentiated MSC for genes with the highest expression and DEG between MSC and fully differentiated tissues uncovered MSC being featured by low immunity and high angiogenic capacity. The direct comparison between differentiation lineages indicated that the expression of a limited number of genes has to change in order to determine cell fate. Functional analysis of the DEG between differentiation lineages indicated that osteogenesis is characterised by larger cell proliferation and cytoskeleton organisation with a crucial role of G-proteins compared to adipogenesis. On the other hand, adipogenesis is driven by PPAR signalling, has greater angiogenesis, lipid metabolism, migration and tumorigenesis capacity compared to osteogenesis. The direct comparison between ASC and BMSC during the same differentiation uncovered that ASC is featured by a greater lipid metabolism compared to BMSC, while BMSC has a more pronounced cell growth and proliferation than ASC. In addition, we uncovered 39 specific gene markers for adipogenesis and 65 for osteogenesis. NAD(P)H dehydrogenase quinone 1 (NQO1), aquaporin 3 (AQP3), stearoyl-CoA desaturase (SCD), fatty acid binding protein 3 and 5 (FABP3 and FABP5) and ferritin light polypeptide (FTL) were among the best adipogenic markers. Hemopexin (HPX), collagenase type 3α (COL3A1), annexin A8-like 1 (ANXA8L1), flotillin 2 (FLOT2) and periostin or osteoblast specific factor (POSTN) were among the best osteogenic markers. Overall, the data indicated that the transcriptome of the two MSC are similar across the conditions studied. In addition, despite the limited DEG between the two MSC, the enrichment of several functions/pathways might indicate differences in therapeutic application. This work was support by the Illinois Regenerative Medicine Institute (IDPH # 63080017).

214 IN VITRO MIGRATION OF ADIPOSE-DERIVED STEM CELLS FROM GFP PIGS INTO POLYCAPROLACTONE SCAFFOLDS TREATED WITH FGF OR BMP2

We have previously demonstrated that adipose-derived stem cells (ASC) enhance healing of craniofacial bone in vivo. The use of scaffolds in large bone defects can further enhance the healing capacity of ASC. In addition, the presence of fully differentiated cells might affect ASC migration/proliferation into scaffolds. In this study, we have evaluated the in vitro capacity of ASC isolated from fat of GFP transgenic pigs to migrate into polycaprolactone (PCL) scaffolds conjugated with FGF or BMP2 with or without combinations of ASC with pig endothelial and/or neuronal cells. The ASC were extracted from the back fat of a GFP boar while the endothelial cells (ENDO) were extracted from the aorta a newborn piglet and the neurons (NEU) from the brain of a 37 days fetus. All cells were used at passage 3. In a 24-well plate, approximately 10 000 cells (only ASC, ENDO, or NEU, or equal combination of ASC+ENDO, ASC+NEU, or ASC+ENDO+NEU) were plated. The cells were grown for 3 days before adding the scaffolds in the wells. The scaffolds were treated with basic human FGF (25 ng mg–1 of scaffold), porcine BMP2 (400 ng mg–1 of scaffold), or no treatment (CTR). The scaffolds were then added to the plate and the medium was changed every 3 days. Using an Olympus IX71 microscope with automatic stage several pictures at 100× and 200× magnifications were taken and time-lapse visualisation of the movement of cells into the scaffold was performed during the first week. At 24 days the scaffolds were fixed with formalin. In order to estimate cell size and visualise non-GFP cells all scaffolds were treated with DAPI. Final photographs of the whole scaffold using a multiple alignment images features at 40× magnification were performed using GFP and DAPI filter plus brightfield. The figures were analysed with ImageJ to quantify the area of GFP and DAPI in the scaffolds. Percentage GFP and DAPI over scaffold area were calculated. Data were analysed using a Proc ANOVA of SAS, with cells and treatment as fixed effects and well as random. At 1 week from the beginning of the trial, we observed ASC cells on the scaffolds. The time-lapse showed ASC actively moving on the scaffold surface and entering into its micropores. The quantification of GFP and DAPI showed a significant larger percentage area covered by GFP cells in scaffolds treated with FGF (P < 0.05) compared to CTR or BMP2 (32 ± 4.6 vs 12.8 ± 9.1 and 3.8 ± 0.1). We observed a numerical lower area covered by GFP in scaffolds treated with BMP2 compared to CTR. The same trends were observed for the area covered by DAPI with a numerically lower colonization of the scaffolds by ENDO when treated with BMP2 vs CTR. Data showed that ASC, as well ENDO and NEU, are able to home into PCL scaffolds. The conjugation of the scaffolds with FGF has a positive effect on ASC migration, with no effects of BMP2. Data support the use of PCL scaffolds to enhance the bone healing capacity in vivo of ASC with a likely further improvement if scaffolds are treated with FGF before implantation.

314 ADIPOSE- AND BONE MARROW-DERIVED MESENCHYMAL STEM CELLS PRESENT LARGE SIMILARITIES IN TRANSCRIPTOME PRIOR TO AND DURING ADIPOGENIC AND OSTEOGENIC DIFFERENTIATION

Previous data support adipose-derived stem cells as an alternative to bone marrow as a source of adult stem cells for therapeutic purposes. The aim of the present study was to directly compare the transcriptome of adipose-derived (ADSC) and bone marrow-derived (BMSC) mesenchymal stem cells prior to differentiation and during in vitro osteogenic and adipogenic differentiation. The ADSC and BMSC were harvested from 3 adult pigs and differentiated in vitro into adipocytes and osteocytes for up to 4 weeks. Prior to differentiation and at differentiation day 2, 7, and 21, cells were harvested and RNA extracted for transcriptomics analysis by a 13 263 oligo 70-mers array (Sus scrofa AROS V1.0 with extension; Operon). Data were normalized by Lowess and statistical analysis was run using ANOVA with Benjamini-Hochberg false discovery rate (FDR) correction. Data mining was carried out using Ingenuity Pathway Analysis and David. Using an FDR of <0.05 for overall tissue effect and a post-hoc correction of P < 0.001, we observed 65 differentially expressed genes (DEG) between ADSC and BMSC before starting differentiation (0.66% of unique genes in the array). Functional analysis uncovered significant enrichment of extracellular matrix genes with direct roles in cell adhesion, migration, movement, and morphology. When the interaction cell type × differentiation × time was assessed, we observed >2 000 DEG with an FDR <0.05. This large number was mostly due to time effects. When pair-wise comparisons between cell types for each time point during the same differentiation were performed (post-hoc P < 0.001), we observed a strikingly low number of DEG. The number of DEG was lower between cell types in osteogenic (<100 DEG) compared with adipogenic (<200 DEG) differentiation. We observed significant enrichment (FDR-corrected P-value cut-off <0.05) of functions related to metabolism, antigen presentation, angiogenesis, and cell cycle in both differentiation conditions. We also observed an overall greater induction of the enriched functions in ADSC and a decrease in BMSC during adipogenic differentiation and the opposite during osteogenic differentiation except for metabolism, which appeared to be larger in ADSC in all cases. Among the significant enriched functions of DEG between the 2 differentiations, we observed enrichment of genes involved in metabolism, cell death, cell-to-cell signalling, and antigen presentation in ADSC during adipogenic compared with osteogenic differentiation. In BMSC we observed enrichment of functions related to cell death, antigen presentation, and lipid metabolism in osteogenic v. adipogenic differentiation. Overall data uncovered a high similarity at the transcriptional level between ADSC and BMSC both prior to differentiation and during differentiation. Those data support ADSC being particularly similar to BMSC. This work was support by the Illinois Regenerative Medicine Institute (IDPH # 63080017).

222 COMPARISON OF COMMERCIAL IN VITRO EMBRYO PRODUCTION OF BRAHMAN DONORS UNDER BRAZILIAN v. PANAMANIAN MANAGEMENT

Brazil is a leading country in the world in commercial use of in vitro-produced bovine embryos, with approximately 200 000 transfers per year (IETS; Thibier, 2009). This model of large-scale commercial in vitro bovine embryo production is now available for Panamanian producers. Because of the tropical environment in Panama, the most popular breed is the Brahman, a Zebu type of cattle that has been shown to have more follicles emerging per follicular wave than Bos taurus type of cattle and, consequently, that produce more oocytes per session of follicular aspiration. This characteristic, added to the embryo production results, permits such a biotechnology to be implemented on a commercial scale and incorporated into the reproduction management of a herd. A comparison of oocyte number and quality, cleavage, and embryo production was made using the same in vitro production system (InVitro Brazil, Mogi Mirim, São Paulo, Brazil) for Brahman donors, both in Brazil and in Panama. Data were compared using a z-test analysis (Table 1). The percentage of cleaved zygotes was greater (P < 0.001) with the Panamanian Brahman donors as compared with the Brazilian Brahman donors (73 v. 69%, respectively). However, the percentage of blastocysts/cleaved zygotes was greater (P < 0.01), indicating a higher blastocyst production rate from the Brazilian donors. No other differences were observed. Thus, in vitro embryo production with Brahman donors could be used as a tool to improve and spread superior genetics within a Panamanian herd and could also serve as a model for other Central American and Caribbean countries under similar management systems. Table 1.Panama and Brazil in vitro Brahman embryo production1 This work was supported by BORN Animal Biotechnology, Panama City, Panama.

313 UNSORTED, FRESHLY ISOLATED PORCINE ADIPOSE-DERIVED STEM CELLS ARE MORE EFFICACIOUS IN BONE HEALING COMPARED WITH PURIFIED CD34+ ADIPOSE-DERIVED STEM CELLS

We have previously shown that heterologous transplantation of porcine adipose-derived stem cells (ADSC) enhances bone healing. Freshly harvested ADSC are a heterogeneous population that contains several types of cells other than stem cells. The isolation of highly purified ADSC could be of clinical importance. In this study, we compared the in vitro growth characteristics and in vivo healing potential of ADSC unsorted or separated using CD34 as a marker. The ADSC were extracted from the back fat of 4 male pigs at 6 months of age. For the in vitro experiment, aliquots of the ADSC were sorted by magnetic beads (Miltenyi Biotec, Gladbach, Germany) into CD34-positive (CD34+) and CD34-negative (CD34–) cell populations. The unsorted ADSC (uADSC), plus the CD34+, CD34–, and a 50:50 mixture of CD34+ and CD34– (MIX) were plated in 24-well plates and differentiated into osteocytes. A robotic stage inverted microscope was used to photograph the entire culture well, and then number, dimension, and density of bone nodules were assessed. Alizarin red (AR) staining was performed and quantified. Cells were harvested before cell plating and then on several time points during expansion, at confluence, and at 3, 6, or 18 days [d] of differentiation for cell counting and RNA extraction. Real-time RT-PCR was performed for CD34, COL1A1, and SPARC genes. For the in vivo experiment, freshly isolated ADSC were sorted by flow cytometry into CD34+ and CD34– cell populations. Unsorted and sorted cells were transplanted, in duplicate, into 10- or 25-mm mandible osteoctomies. Mandibles were harvested after 8 weeks for evaluation of healing by DEXA scanning. In vitro data were statistically analysed using a mixed model (SAS) with time and cell type as fixed effect and pig as the random effect. The in vivo data were assessed by ANOVA with cell types as the fixed effect and pig as the random effect. Freshly harvested ADSC contained 42.3 ± 11.0% CD34+ cells. The uADSC reached confluence at 6 days after plating, whereas other cell types reached confluence at 16 days. Expression of CD34 decreased after plating but was similar between cell types. Among osteogenic genes, only expression of SPARC increased during differentiation. The number of osteogenic nodules was higher (P < 0.05) in uADSC than the in other cell types, but the area and nodule density were similar to CD34– and greater (P < 0.05) than CD34+ and MIX. The amount of AR was higher (P < 0.05) in uADSC compared with CD34– and MIX but similar to CD34+. In the in vivo trial, uADSC had a greater (P < 0.05) healing compared with sorted cells. Among those, CD34– cells appeared to increase healing compared with CD34+ cells. Results indicate that CD34+ cells do not differ significantly from CD34– in the in vitro osteogenic differentiation but have lower in vivo healing capacity; however, in vitro data were confused by a lack of pure CD34– cells. The freshly isolated ADSC have a greater healing capacity than sorted cells, as indicated by in vitro and in vivo experiments. Overall our data indicate that the sorting of ADSC CD34+ cells is not of clinical relevance.

Effects of the peroxisome proliferator-activated receptor-alpha agonists clofibrate and fish oil on hepatic fatty acid metabolism in weaned dairy calves

Peroxisome proliferator-activated receptor-alpha (PPARalpha) agonists increase fatty acid oxidation in liver of nonruminants. If similar effects occur in dairy cattle, enhanced hepatic oxidative capacity could decrease circulating nonesterified fatty acids and hepatic triacylglycerol accumulation in periparturient cows. The objectives of this study were 1) to determine whether partitioning of fatty acid metabolism by liver slices from weaned Holstein calves treated with PPARalpha agonists in vivo is altered compared with partitioning by liver slices from control (untreated) calves, and 2) to measure in vitro metabolism of palmitate and oleate by bovine liver slices and relate these to mRNA abundance for key enzymes. Weaned male Holstein calves (7 wk old; n=15) were assigned to 1 of 3 groups for a 5-d treatment period: control (untreated), clofibrate (62.5 mg/kg of BW), or fish oil (250 mg/kg of BW). Calves treated with clofibrate consumed less dry matter. Body weight, liver weight, liver weight:body weight ratio, blood nonesterified fatty acids, beta-hydroxybutyrate, and liver composition were not significantly different among treatments. Liver slices were incubated for 2, 4, and 8 h to determine in vitro conversion of [1-(14)C] palmitate and [1-(14)C] oleate to CO(2), acid-soluble products, esterified products, and total metabolism. In liver slices incubated for 8 h, conversion of palmitate to CO(2) was greater for calves treated with clofibrate compared with control calves or calves treated with fish oil. Conversion of palmitate to esterified products, total palmitate metabolism, and metabolism of oleate were not different among treatments. Conversion of palmitate to CO(2) was greater than that from oleate for all treatments, but rates of total metabolism did not differ. Clofibrate increased or tended to increase liver expression of several PPARalpha target genes involved in fatty acid oxidation (e.g., ACADVL, ACOX1, CPT1A), whereas fish oil did not significantly affect genes associated with fatty acid oxidation but tended to increase DGAT1. Overall, our data indicated that bovine liver responded to clofibrate treatment but not fish oil, although increases in hepatic lipid metabolism were much less than those reported in rodents treated with clofibrate or fish oil. Applications of PPARalpha agonists may be of interest to increase the rate of hepatic fatty acid oxidation and decrease triacylglycerol accumulation in periparturient dairy cows.

Adipose tissue depots of Holstein cows are immune responsive: inflammatory gene expression in vitro

The transcriptional response of adipose tissue depots with respect to their immune responsiveness in dairy cows remains largely unknown. Thus, we examined mRNA expression and responsiveness of subcutaneous (SUB) and mesenteric (MES) adipose tissue from nonpregnant dairy cows to a short-term (2 h), in vitro lipopolysaccharide (LPS) challenge (20 microg/mL in physiological saline). Abundance of mRNA for tumor necrosis factor-alpha (TNFA), interleukin-6 (IL6), serum amyloid A3 (SAA3), toll-like receptor 4 (TLR4), monocyte chemoattractant protein-1 (CCL2), and RANTES/chemokine C-C motif ligand 5 (CCL5) were analyzed using quantitative polymerase chain reaction (PCR) from tissue samples collected at slaughter from 5 nonpregnant/nonlactating Holstein cows. Prior to LPS challenge, SAA3 mRNA abundance was greater in MES than SUB tissue. Regardless of depot site, LPS led to greater mRNA abundance of TNFA and IL6 and was more pronounced for IL6 in MES. We also observed a marked increased in expression of CCL2, CCL5, TLR4, IL6, and TNFA in both MES and SUB during the 2-h incubation with saline alone (ie, the control). Because mRNA expression of the apoptotic markers B-cell CLL/lymphoma 2 (BCL2) and tumor protein p53 (TP53) did not differ during the 2-h incubation, it is less likely that the response to saline was a result of increased rate of cell death during incubation. Analysis using semiquantitative PCR of the 16s rRNA gene in cDNA from tissue explants revealed the presence of bacteria likely arising from contamination during sample collection. Furthermore, surfactant medium from about 50% of explant cultures had viable aerobic bacteria without differences between treatments or tissue samples. Thus, the presence of bacteria could partly explain the large increase in inflammatory-related genes after 2-h incubation with saline. The higher SAA3 expression in MES suggests that this acute-phase protein has a role in lipid metabolism and/or transport during an immune challenge. Overall, results provided evidence that adipose depots of dairy cows are capable of synthesizing chemokines and are immune responsive when exposed to inflammatory conditions that can arise from a pathogenic insult or during and soon after parturition.

Identification of internal control genes for quantitative polymerase chain reaction in mammary tissue of lactating cows receiving lipid supplements

Dietary lipid supplements affect mammary lipid metabolism partly through changes in lipogenic gene expression. Quantitative PCR (qPCR) is a sensitive, reliable, and accurate technique for gene expression analysis. However, variation introduced in qPCR data by analytical or technical errors needs to be accounted for via normalization using appropriate internal control genes (ICG). Objectives were to mine individual bovine mammary microarray data on >13,000 genes across 66 cows from 2 independent studies to identify the most suitable ICG for qPCR normalization. In addition to unsupplemented control diets, cows were fed saturated or unsaturated lipids for 21 d or were infused with supplements (butterfat, conjugated linoleic acid mixture, long-chain fatty acids) into the abomasum to modify milk fat synthesis and fatty acid profiles. We identified 49 genes that did not vary in expression across the 66 samples. Subsequent gene network analysis revealed that 22 of those genes were not co-regulated. Among those COPS7A, CORO1B, DNAJC19, EIF3K, EMD, GOLGA5, MTG1, UXT, MRPL39, GPR175, and MARVELD1 (sample/reference expression ratio = 1 +/- 0.1) were selected for PCR analysis upon verification of goodness of BLAT/BLAST sequence and primer design. Relative expression of B2M, GAPDH, and ACTB, previously used as ICG in bovine mammary tissue, was highly variable (0.9 +/- 0.6) across studies. Gene stability analysis via geNorm software uncovered MRPL39, GPR175, UXT, and EIF3K as having the most stable expression ratio and, thus, suitable as ICG. Analysis also indicated that use of 3 ICG was most appropriate for calculating a normalization factor. Overall, the geometric average of MRPL39, UXT, and EIF3K is ideal for normalization of mammary qPCR data in studies involving lipid supplementation of dairy cows. These novel ICG could be used for normalization in similar studies as alternatives to the less-reliable ACTB, GAPDH, or B2M.

179 INTERNAL CONTROL GENES FOR QUANTITATIVE PCR OF PORCINE MESENCHYMAL STEM CELLS DURING ADIPOGENIC AND OSTEOGENIC DIFFERENTIATION IN VITRO

Uncovering transcriptomic adaptation of porcine adult stem cells during differentiation in vitro towards a target tissue can provide important information for human adult stem cell therapeutic applications. High-throughput microarrays allow the parallel analysis of thousands of genes simultaneously. However, quantitative RT-PCR (qPCR) remains the chosen method for high-precision mRNA abundance analysis and microarray data verification. Essential for qPCR reliability is data normalization using appropriate internal control genes (ICG). The objective of this study was to find reliable ICG for normalization of qPCR data for porcine adult mesenchymal stem cells induced to differentiate toward adipogenic and osteogenic lineages. Mesenchymal stem cells were harvested from porcine adipose tissue and bone marrow and cultured in vitro with specific differentiation media for up to 3 weeks. The experiment was analyzed by a porcine 13 000-oligo microarray, and data were mined to uncover highly stable genes. Statistical analysis was performed using PROC MIXED of SAS (SAS Institute Inc., Cary, NC, USA). The model included fixed effect of time, cell type, differentiation, and all interaction between them. Pig (n = 3) was considered a random variable. Initial microarray analysis revealed 27 genes with high stability across all samples (sample/reference = 1 ± 0.2). Gene network analysis identified 20 genes without known co-regulation (i.e. common up-stream regulators). Among those genes, we could design high-quality primers (i.e. absence of primer-dimer, single amplicon) only for 10 of them (BANF1, DAK, DPH3, GTF2H3, PRR3, NSUN5, NUBP, SSU72, TIMM17B, and VPS4A), and qPCR using a standard curve was run. Stability of those genes was assessed using pairwise comparison of expression ratios. All genes examined were highly stable with TIMM17B, NSUN5, and VPS4A as the most stable. All the potential ICG tested had significant time, tissue × differentiation, and tissue × time effects. For the 3 most stable genes, we did not observe additional effects, while other ICG were significantly affected by differentiation. The analysis also indicated calculation of the normalization factor using the 3 most stable genes (NF3) as highly reliable; however, the use of 7 genes (NF7) would provide the best reliability. To assess the effect of normalization, we ran qPCR for DBI and COL1A1, genes specific of adipogenic and osteogenic differentiation, respectively. The effect on qPCR data normalization was highly apparent for the adipogenic differentiation and less apparent for the osteogenic differentiation. No differences were observed when qPCR data were normalized by NF3 or NF7. The combination of microarray data and pairwise analysis uncovered novel and high reliable ICG for qPCR normalization in adult porcine stem cells induced into adipogenic and osteogenic lineages. This work was supported by the Illinois Regenerative Medicine Institute.

282 ADIPOGENIC DIFFERENTIATION IN VITRO OF PORCINE ADULT MESENCHYMAL STEM CELLS

The quantity and accessibility of subcutaneous adipose tissue in humans make it an attractive alternative to bone marrow as a source of adult stem cells for therapeutic purposes. However, before such a cell source substitution can be proposed, the properties of stem cells derived from adipose tissue (ADSC) and bone marrow (BMSC), and their differentiated progeny must be compared in an animal model, such as swine, that adequately simulates the structure and physiology of humans. The objective of this work was to induce adult porcine stem cells isolated from subcutaneous adipose tissue and bone marrow to differentiate in vitro along the adipogenic lineage and to compare their transcript profile properties. ADSC and BMSC were isolated from subcutaneous adipose tissue and femurs of adult pigs, respectively, and differentiated along the adipogenic lineage using specific inducing medium. Cells were incubated up to 4 weeks with medium replaced every 3 days. Histological staining with Oil Red O was performed at 0, 2, 4, 7, 14, 21, 28 days of differentiation (dd) to confirm the adipogenic differentiation. RNA was also extracted at these time points. qPCR was performed on PPARG, DBI, ACSL1, CD36, CEBPA, DGAT2, ADFP, ADIPOQ, SCD. The geometrical mean of GTF2H3, NUBP, and PPP2CB was used as an internal control. Gene expression was analyzed using a mixed model of SAS with repeated time. The adipogenic differentiation of both ADSC and BMSC was confirmed by the Oil Red O positive staining. The relative mRNA abundance of all the genes at dd0 was similar between the ADSC and BMSC. The relative mRNA abundance of most of the genes was also similar between ADSC and BMSC throughout the adipogenic differentiation. ACSL1 and ADIPOQ had analogous expression patterns among the cell types. ACSL1 had relatively large mRNA abundance before differentiation, but ADIPOQ was barely detectable. As a consequence of differentiation, ACSL1 increased in relative mRNA abundance about 10-fold, whereas ADIPOQ mRNA increased about 1000-fold. Temporal expression patterns of SCD, DGAT2, and ADFP were similar. The increase in gene expression was >800% for SCD, >500% for ADFP, and >50 000% for DGAT2 after 7dd. ADSC had significantly higher expression of those genes compared to BMSC at 14 and 28dd. Both ADIPOQ and DGAT2 were almost undetectable prior to differentiation. mRNA expression of CD36 and DBI was similar with a significantly larger increase in expression of ADSC compared with BMSC. Relative mRNA abundance of CEBPA and PPARG was also larger in ADSC compared with BMSC; however, BMSC had a remarkable increase in temporal expression of those genes throughout adipogenic differentiation. These results suggest both cell types can differentiate towards the adipogenic lineage but with quantitatively different gene expression patterns. More investigation is needed before the ADSC can be considered a practical alternative source for stem cells in future human clinical applications. This research was supported by the Illinois Regenerative Medicine Institute.

280 MULTILINEAGE POTENTIAL OF PORCINE BONE MARROW AND ADIPOSE-DERIVED MESENCHYMAL STEM CELLS IN 3-D ALGINATE HYDROGELS

Adipose tissue presents an appealing alternative to bone marrow as a source of mesenchymal stem cells (MSC). However, in order to enhance cell proliferation and differentiation, 3-dimensional (3-D) culture may be required. A 3-D culture has benefits due to its more in vivo-like environment. Further, to form a functional tissue, a scaffold material is required to ensure proper shape and allow for efficient delivery of nutrients and growth factors. Alginate, a resorbable hydrogel, is a potential injectable scaffold for fat and bone tissue engineering due to its high biocompatibility, gelation with calcium and slow dissolution in a physiologic environment. In the present study, we examined the viability, gene expression and morphology of MSC, isolated from porcine adipose (ADSC) and bone marrow (BMSC), during osteogenic and adipogenic differentiation in a 3D alginate hydrogel environment for 0, 7 and 14 days (d). ADSC and BMSC were infused into alginate hydrogels, which polymerized upon the addition of Ca+2 ions. Both stem cell types were differentiated into osteoblasts using 0.1 μm dexamethasone, 10 mm beta glycerophosphate and 50 μm ascorbic acid, whereas adipocytes were differentiated using 10 μm insulin, 1 μm dexamethasone, and 0.5 mm IBMX. Osteogenic differentiation was confirmed using alkaline phosphatase, Von Kossa, and alizarin red S staining and adipogenic differentiation was confirmed using Oil Red O. Cell viability and proliferation was quantified using the MTT assay. Gene expression was measured using qPCR. The morphology of ADSC and BMSC differentiated toward osteogenic lineages changed with both cell types forming osteogenic nodules over time. The nodules formed by ADSC were larger in diameter than those formed by BMSC. Unlike the osteogenic cells that formed nodules, the ADSC and BMSC differentiated into adipogenic cells showed no significant changes in cell size or aggregation. Gene expression results indicated increased PPARG expression in BMSC with time whereas ADSC showed a peak of expression on day 7 and then decreased. ADSC showed increased (14-fold) PPRG expression when compared with BMSC. ADSC had 160-fold less expression of ALP than BMSC. BMSC showed a 16-fold higher expression level of BGLAP than ADSC. ADSC showed a 15.8% higher expression than BMSC for COL1a1. Both ADSC and BMSC showed similar trends SPARC expression, but BMSC had a 12-fold higher expression of SPP1 than ADSC. In summary, both types of mesenchymal stem cells successfully differentiated into both lineages and maintained viability in the hydrogel over time. In conclusion, alginate is a viable scaffold material for the differentiation of mesenchymal stem cells for tissue engineering applications. These results allow for future studies using the pig as an in vivo fat and bone tissue engineering model. This research was supported by the Illinois Regenerative Medicine Institute.

Internal controls for quantitative polymerase chain reaction of swine mammary glands during pregnancy and lactation

High-throughput microarray analysis is an efficient means of obtaining a genome-wide view of transcript profiles across physiological states. However, quantitative PCR (qPCR) remains the chosen method for high-precision mRNA abundance analysis. Essential for reliability of qPCR data is normalization using appropriate internal control genes (ICG), which is now, more than ever before, a fundamental step for accurate gene expression profiling. We mined mammary tissue microarray data on >13,000 genes at -34, -14, 0, 7, 14, 21, and 28 d relative to parturition in 27 crossbred primiparous gilts to identify suitable ICG. Initial analysis revealed TBK1, PCSK2, PTBP1, API5, VAPB, QTRT1, TRIM41, TMEM24, PPP2R5B, and AP1S1 as the most stable genes (sample/reference = 1 +/- 0.2). We also included 9 genes previously identified as ICG in bovine mammary tissue. Gene network analysis of the 19 genes identified AP1S1, API5, MTG1, VAPB, TRIM41, MRPL39, and RPS15A as having no known co-regulation. In addition, UXT and ACTB were added to this list, and mRNA abundance of these 9 genes was measured by qPCR. Expression of all 9 of these genes was decreased markedly during lactation. In a previous study with bovine mammary tissue, mRNA of stably expressed genes decreased during lactation due to a dilution effect brought about by large increases in expression of highly abundant genes. To verify this effect, highly abundant mammary genes such as CSN1S2, SCD, FABP3, and LTF were evaluated by qPCR. The tested ICG had a negative correlation with these genes, demonstrating a dilution effect in the porcine mammary tissue. Gene stability analysis identified API5, VABP, and MRPL39 as the most stable ICG in porcine mammary tissue and indicated that the use of those 3 genes was most appropriate for calculating a normalization factor. Overall, results underscore the importance of proper validation of internal controls for qPCR and highlight the limitations of using absence of time effects as the criteria for selection of appropriate ICG. Further, we showed that use of the same ICG from one organism might not be suitable for qPCR normalization in other species.

182 OSTEOPONTIN GENE EXPRESSION IN IMMATURE AND MATURE SWINE CUMULUS CELLS AND OOCYTES

Osteopontin (OPN) is an acidic single-chain phosphorylated glycoprotein found in both the female and the male reproductive tract that is believed to facilitate reproduction. It was recently reported in swine that OPN improves in vitro fertilization (Hao et al. 2006 Biol. Reprod. 75, 726–733). In bovine, OPN improves the efficiency of in vitro embryo production, and it has been detected on the zona pellucida (ZP) of immature and mature oocytes (Monaco et al. 2007 J. Anim. Sci. 85, 529 abst). This study was designed to evaluate the gene expression of OPN (SPP1) in immature and mature swine cumulus cells and oocytes. Ovaries from a local slaughterhouse were collected on three different days. Half of the immature cumulus–oocyte complexes (COCs) from each day were vortexed in 1 mL TCM-199 HEPES containing 10 mg mL–1 hyaluronidase to separate immature cumulus cells, while the other half of the COCs were maturated for 40-42 h and then the cumulus cells were separated. RNA from cumulus cells and oocytes was extracted and genomic DNA was removed by DNase treatment. cDNA was synthesized using 100 ng of RNA and diluted 50% with DNase–RNase-free water. The RT-PCR product from cumulus cells and oocytes was run in a 2% agarose gel stained with ethidium bromide to verify the presence of SPP1. Relative mRNA abundance between immature and mature cumulus cells was assessed by SYBR green real-time RT–PCR run in triplicate using a 6-point twofold dilution standard curve. GAPDH was used as internal control. Primers for SPP1 and GAPDH were designed spanning an exon/exon junction. The presence of a single and specific PCR product was assessed by gel electrophoresis (a single band was expected at 100 and 90 bp, respectively, for SPP1 and GAPDH), dissociation curve, and sequencing. A t-test was used to assess differences between immature (n = 3) and mature (n = 3) cumulus cells. SPP1 was detected in agarose gel in both immature and mature oocytes and cumulus cells. Cumulus cells presented a Ct for SPP1 ranging from 20 (immature) to 29 (mature). Immature cumulus cells showed a 32-fold larger mRNA abundance compared to the mature cumulus cells (P < 0.05) when data were transformed using a standard curve. Results showed expression of SPP1 in porcine oocytes and cumulus cells. However, maturation significantly decreased the expression of SPP1 in cumulus cells. The presence of SPP1 mRNA in oocytes and cumulus cells and the larger mRNA abundance before maturation may suggest a role of this protein prior to maturation of oocytes. Additional studies will be required to determine the specific role of SPP1 in oocyte maturation in the pig.

408. Liver gene expression in suckled postpartum beef cows maintained on moderate and improved subtropical pasture

The liver is the first organ to receive absorbed nutrients from the splanchnic vasculature1 which places the liver at an important juncture between nutrition, metabolic homeostasis and reproductive function. The best described component of this interface is secretion of IGF-1 by the liver and dependence of ovarian follicular maturation on hepatic-derived IGF-12. The aim in the present study was to ascertain the expression of hepatic genes associated with metabolic regulation in postpartum beef cows maintained on moderate or improved pasture, and with contrasting liveweight and body condition. Multiparous Droughtmaster cows (Bos taurus × Bos indicus) were placed on moderate (MP, n = 7) or improved (IP, n = 7) pasture at 6–7 months of gestation and remained on the treatments after calving. Liver biopsies were taken 6 weeks after calving and gene expression was determined by quantitative PCR using SYBR Green3. Week 6 represents attainment of the plateau in nutrient demand for lactation. Data were analysed by ANOVA using SAS STAT. One week after calving, IP cows had greater (P < 0.01) liveweight and body condition score (BCS) than MP cows (585 ± 12 kg and 528 ± 21 kg; 3.7 ± 0.2 BCS and 2.3 ± 0.2 BCS). IP cows had greater (P < 0.05) relative expression of hepatic genes associated with cholesterol biosynthesis (sterol regulatory element binding factor, SREBF2; peroxisome proliferators-activated receptor delta, PPARD), fatty acid biosynthesis (carnitine palmitoyl-transferase, CPT1A; acyl-CoA oxidase, ACOX1; fatty acid desaturase 1, FADS1; sterol regulatory element binding factor 1, SREBF1) and insulin signalling (hepatic insulin receptor substrate 1, IRS1). IP cows resumed cyclic ovarian function between 11–16 weeks postpartum and one MP cow had cycled by 16 weeks. The differences in expression of metabolic genes between MP and IP cows may have partly contributed to differences in reproductive function postpartum. (1) Drackley J et al. 2006 Journal of Dairy Science 89:1324–36 (2) Lucy MC 2000 Journal of Dairy Science 83:1635–47 (3) Loor JJ et al. 2006 Physiological Genomics 27:29–41

286 OSTEOGENIC DIFFERENTIATION IN VITRO OF PORCINE ADULT MESENCHYMAL STEM CELLS

The quantity and accessibility of subcutaneous adipose tissue in humans make it an attractive alternative to bone marrow as a source of adult stem cells for therapeutic purposes. However, before such a cell source substitution can be proposed, the properties of stem cells derived from adipose (ADSCs) and bone marrow (MSCs) and their differentiated progeny must be compared in an animal model that adequately simulates the structure and physiology of humans. The objective of this work was to induce adult porcine stem cells isolated from subcutaneous adipose tissue and bone marrow to differentiate in vitro along the osteoblastic lineage and to compare their morphological, phenotypic, and genotypic properties. MSCs and ADSCs were isolated respectively from femurs and subcutaneous adipose tissue of adult pigs and cultured in vitro using DMEM supplemented with 10% fetal bovine serum (FBS), 1% penicillin G-streptomycin, and 5.6 mg L–1 amphotericin B. After 3 passages, cells were differentiated along the osteogenic lineage using lineage-specific inducing medium. Osteogenic medium contained 100 nm dexamethasone, 10 mm β-glycerophosphate, and 0.005 mm ascorbic acid-2-phosphate. Osteogenic cultures were incubated for 4 weeks in 95% air and 5% CO2 at 39�C. Spent medium was replaced with fresh medium every 3 days. Histological staining with alkaline phosphatase, Von Kossa, and alizarin red S were performed at 0, 2, 4, 7, 14, 21, and 28 days of differentiation (dd). At the same time points, RNA was extracted. qPCR was performed on COL1A1, BGLAP, SPARC, and SPP1. As internal control, the geometrical mean of GTF2H, NUBP, and PPP2C was used. Relative mRNA abundance between cell types was calculated using 1/efficiencydCT. The osteogenic differentiation of both MSCs and ADScs was confirmed by the organization of the cells in nodules and by alkaline phosphatase-, Von Kossa-, and alizarin red S-positive staining. The percent relative abundance of the 4 genes in both cell types was COL1A1 (ca. 50) > SPARC (ca. 45) > SPP1 (ca. 5) > BGLAP ( < 0.1). Cell types showed similar mRNA abundance for COL1A1 and SPARC while SPP1 and BGLAP were, respectively, 10- and 19-fold higher in MSCs than in ADSCs. All of the genes had the same pattern among tissues during differentiation except for SPP1, which showed a >10-fold increase at 14 v. 0 dd only for MSCs. Adipose-derived stem cells demonstrated a clear osteogenic differentiation and similar expression and pattern of the two osteogenic genes most abundant in MSCs (COL1A1 and SPARC). However, the higher abundance of SPP1 and BGLAP and the different behavior of SPP1 in MSCs suggest a different transcription profile between the two cell types. From these preliminary results, adipose tissue can be a practical alternative source for stem cells in future human clinical applications.

Plasma Paraoxonase, Health, Inflammatory Conditions, and Liver Function in Transition Dairy Cows

Paraoxonase (PON) is a liver protein with hydrolase activity that is released into the blood stream. Paraoxonase may serve as an index of liver function because it is drastically reduced in chronic liver damage. Sixty-seven periparturient dairy cows were used to evaluate the relationship between plasma PON, health problems, inflammatory conditions, and liver function. Baseline plasma PON concentrations during the first 30 d in milk (DIM) were retrospectively used to group cows into quartiles. Metabolic profile, lipid metabolites (e.g., nonesterified fatty acids, beta-hydroxybutyrate), inflammatory indices (haptoglobin, ceruloplasmin), low and high density lipoprotein cholesterol, vitamin A, vitamin E, reactive oxygen metabolites, total antioxidants, and PON in plasma were measured 2 wk before to 8 wk after calving. Weekly milk yield, body condition score, and all health problems were recorded. After parturition (7 DIM), cows in the lower PON group had the lowest plasma concentrations of negative acute phase proteins compared with the higher PON group for retinol binding protein (23.2 +/- 2.86 vs. 36.0 +/- 2.96 microg/dL of vitamin A), albumin (31.6 +/- 0.73 vs. 33.9 +/- 0.75 g/L), total cholesterol (2.04 +/- 0.30 vs. 2.45 +/- 0.42 mmol/L), and the highest concentrations of haptoglobin (0.67 vs. 0.24 +/- 0.03 g/L; positive acute phase protein) and globulins (37.2 vs. 32.3 +/- 1.4 g/L). Plasma bilirubin was highest in the cows (10.1 vs. 6.2 +/- 0.6 micromol/L) in the lowest PON quartile. Plasma PON was negatively correlated with haptoglobin (r = -0.39) and bilirubin (r = -0.42) and positively correlated with retinol binding protein (r = 0.54), albumin (r = 0.38), and cholesterol (r = 0.55) fractions. A total of 82.3% of cows in the lower quartile and no cows in the upper quartile experienced serious inflammation. Lower quartile cows produced 28.1 +/- 10.3 kg of milk/d; whereas upper quartile cows produced 38.3 +/- 7.7 kg of milk/d during the first 30 DIM. A reduction in the ability of the liver to cope with the increased metabolic demand near parturition in dairy cows can be diagnosed using changes in baseline plasma PON.