Successful in vivo Transplantation of Cultured and Enriched Testicular Germ Cells of Pre-Pubertal Bucks to Busulfan-Treated Homologous Recipients.

The objective of the present study was to establish a workable approach for the production of germ cell (GC)-depleted recipient goat model using intra-testicular busulfan treatment and transplantation of cultured and enriched caprine-male GC (cmGCs) into the homologous recipients under ultrasonography (USG) guidance. The evaluation of post-transplantation colonization of donor cmGCs and restoration of the normal architecture of seminiferous tubules (ST) was performed. For this, the cmGCs of pre-pubertal male goats were isolated and enriched by differential platting for culture until the third passage. Thereafter, cells were harvested and further enriched by magnetic-activated cell sorting using rabbit-anti-CD90 antibody. After confirmation of metabolic viability (MTT-assay) and cluster-forming ability (crystal violet staining) of CD90+ cmGCs, the cells were labeled with a lipophilic red-fluorescent dye (PKH26) before transplanted into the recipient male goats by injection directly into the mediastinum testes under USG guidance. The colonization and repopulation of transplanted CD90+ cmGCs into the recipient ST was observed up to 8 weeks post-transplantation. The PKH26-labeled donor cell-derived colonies were identified in enzymatically digested ST and cryosections of recipient testes. Moreover, histochemical analyses revealed the restoration of the normal architecture of ST of recipient testis after GC transplantation. Therefore, the results suggest that the reproductive competence of infertile animals can be restored through mGC therapy and thus the methodology presented herein could be useful to obtain donor mGCs-derived functional male gametes in the recipient animal testis.

Temperature response of enriched pre-pubertal caprine male germline stem cells in vitro.

The present study aims to evaluate culture temperature-dependent variation in survival, growth characteristics and expression of stress, pluripotency, apoptosis, and adhesion markers in enriched caprine male germline stem cells (cmGSCs). For this, testes from pre-pubertal bucks (4-5 months; n = 4) were used to isolated cells by a two-step enzymatic digestion method. After enrichment of cmGSCs by multiple methods (differential platting, Percoll density gradient centrifugation, and MACS), viability of CD90+ cells was assessed before co-cultured onto the Sertoli cell feeder layer at different temperatures (35.5, 37.0, 38.5, and 40.0 °C). The culture characteristics of cells were compared with MTT assay (viability); cluster-forming activity assay, SA-ß1-gal assay (senescence), BrdU assay (proliferation), and transcript expression analyses by qRT-PCR. Moreover, the co-localization of pluripotency markers (UCHL-1, PLZF, and DBA) was examined by a double-immunofluorescence method. The cells grown at 37.0 °C showed faster proliferation with a significantly (p < 0.05) higher number of viable cells and greater number of cell clusters, besides higher expression of pluripotency markers. The transcript expression of HSPs (more noticeably HSP72 than HSP73), anti-oxidative enzymes (GPx and CuZnSOD), and adhesion molecule (ß1-integrin) was significantly (p < 0.05) downregulated when grown at 35.0, 38.5, or 40.0 °C compared with 37.0 °C. The expression of pluripotency-specific transcripts was significantly (p < 0.05) lower in cmGSCs grown at the culture temperature lower (35.5 °C) or higher (38.5 °C and 40.0 °C) than 37.0 °C. Overall, the culture temperature significantly affects the proliferation, growth characteristics, and expression of heat stress, pluripotency, and adhesion-specific markers in pre-pubertal cmGSCs. These results provide an insight to develop strategies for the improved cultivation and downstream applications of cmGSCs.

Characterization of adiponectin concentrations and molecular weight forms in serum, seminal plasma, and ovarian follicular fluid from cattle.

Adiponectin (AdipoQ), an adipocyte-derived hormone, is one of the most abundant adipokines in the blood circulation. Adiponectin has various metabolic functions, such as improving insulin sensitivity in humans and rodents. The role of AdipoQ in reproduction is not yet fully understood, but the expression of AdipoQ in reproductive tissues has been observed in various animals and humans, including chicken testis, bovine ovary, and human placenta. The objective of this study was to characterize AdipoQ in the bovine body fluids related to reproduction. Therefore, we evaluated the seminal plasma (SP) from breeding bulls (n = 29) and follicular fluid (FF) from heifers (n = 14), and we also collected blood samples from these animals. In addition, blood samples from other bulls (n = 30) and heifers (n = 14) were assayed for AdipoQ. The concentrations were assessed using a bovine-specific ELISA, and the molecular weight (MW) pattern of the AdipoQ protein was estimated by the Western blot analysis. The SP AdipoQ concentrations were approximately 180-fold lower compared with that in the serum concentrations. Furthermore, the AdipoQ concentrations in the serum and SP were positively correlated. The MW patterns of AdipoQ in the serum and SP were different such that the high MW form of AdipoQ was more abundant in the SP than serum. The AdipoQ concentrations in the serum and SP also increased with age: old bulls (>6 years) had higher AdipoQ concentrations in the serum and SP than bulls aged 24 months or lesser (P < 0.05). In the FF, the AdipoQ concentrations were 1.6-fold lower than those in the corresponding serum samples, and the concentrations in the serum and FF were not correlated (P > 0.1). In the FF, only the middle MW forms of AdipoQ were detectable by Western blotting. The MW pattern in the serum did not differ between the sexes. Our data provide both the AdipoQ concentration and the MW patterns for bovine body fluids related to reproduction.

Nicotinic acid increases adiponectin secretion from differentiated bovine preadipocytes through G-protein coupled receptor signaling.

The transition period in dairy cows (3 weeks prepartum until 3 weeks postpartum) is associated with substantial mobilization of energy stores, which is often associated with metabolic diseases. Nicotinic acid (NA) is an antilipolytic and lipid-lowering compound used to treat dyslipidaemia in humans, and it also reduces non-esterified fatty acids in cattle. In mice the G-protein coupled receptor 109A (GPR109A) ligand NA positively affects the secretion of adiponectin, an important modulator of glucose and fat metabolism. In cattle, the corresponding data linking NA to adiponectin are missing. Our objective was to examine the effects of NA on adiponectin and AMPK protein abundance and the expression of mRNAs of related genes such as chemerin, an adipokine that enhances adiponectin secretion in vitro. Differentiated bovine adipocytes were incubated with pertussis toxin (PTX) to verify the involvement of GPR signaling, and treated with 10 or 15 µM NA for 12 or 24 h. NA increased adiponectin concentrations (p ≤ 0.001) and the mRNA abundances of GPR109A (p ≤ 0.05) and chemerin (p ≤ 0.01). Pre-incubation with PTX reduced the adiponectin response to NA (p ≤ 0.001). The NA-stimulated secretion of adiponectin and the mRNA expression of chemerin in the bovine adipocytes were suggestive of GPR signaling-dependent improved insulin sensitivity and/or adipocyte metabolism in dairy cows.

Trans-cinnamic acid increases adiponectin and the phosphorylation of AMP-activated protein kinase through G-protein-coupled receptor signaling in 3T3-L1 adipocytes.

Adiponectin and intracellular 5'adenosine monophosphate-activated protein kinase (AMPK) are important modulators of glucose and fat metabolism. Cinnamon exerts beneficial effects by improving insulin sensitivity and blood lipids, e.g., through increasing adiponectin concentrations and AMPK activation. The underlying mechanism is unknown. The Gi/Go-protein-coupled receptor (GPR) 109A stimulates adiponectin secretion after binding its ligand niacin. Trans-cinnamic acid (tCA), a compound of cinnamon is another ligand. We hypothesize whether AMPK activation and adiponectin secretion by tCA is transmitted by GPR signaling. Differentiated 3T3-L1 cells were incubated with pertussis toxin (PTX), an inhibitor of G(i)/G(o)-protein-coupling, and treated with different tCA concentrations. Treatment with tCA increased adiponectin and the pAMPK/AMPK ratio (p ≤ 0.001). PTX incubation abolished the increased pAMPK/AMPK ratio and adiponectin secretion. The latter remained increased compared to controls (p ≤ 0.002). tCA treatment stimulated adiponectin secretion and AMPK activation; the inhibitory effect of PTX suggests GPR is involved in tCA stimulated signaling.

Supplementation with conjugated linoleic acids extends the adiponectin deficit during early lactation in dairy cows.

Decreasing insulin sensitivity (IS) in peripheral tissues allows for partitioning nutrients towards the mammary gland. In dairy cows, extensive lipid mobilization and continued insulin resistance (IR) are typical for early lactation. Adiponectin, an adipokine, promotes IS. Supplementation with conjugated linoleic acids (CLA) in rodents and humans reduces fat mass whereby IR and hyperinsulinemia may occur. In dairy cows, CLA reduce milk fat, whereas body fat, serum free fatty acids and leptin are not affected. We aimed to investigate the effects of CLA supplementation on serum and adipose tissue (AT) adiponectin concentrations in dairy cows during the lactation driven and parity modulated changes of metabolism. High yielding cows (n=33) were allocated on day 1 post partum to either 100 g/day of a CLA mixture or a control fat supplement (CON) until day 182 post partum. Blood and subcutaneous (sc) AT (AT) biopsy samples were collected until day 252 post partum to measure adiponectin. Serum adiponectin decreased from day 21 pre partum reaching a nadir at calving and thereafter increased gradually. The distribution of adiponectin molecular weight forms was neither affected by time, parity nor treatment. Cows receiving CLA had decreased serum adiponectin concentrations whereby primiparous cows responded about 4 weeks earlier than multiparous cows. The time course of adiponectin concentrations in sc AT (corrected for residual blood) was similar to serum concentrations, without differences between CLA and CON. CLA supplementation attenuated the post partum increase of circulating adiponectin thus acting towards prolongation of peripartal IR and drain of nutrients towards the mammary gland.

The C-terminal domain of Salmonella enterica serovar typhimurium OmpA is an immunodominant antigen in mice but appears to be only partially exposed on the bacterial cell surface.

We examined the way the major outer membrane protein OmpA of Salmonella enterica serovar Typhimurium is recognized by the mouse immune system, by raising a panel of 12 monoclonal antibodies (MAbs) against this protein. Interaction between OmpA and these MAbs is competitively inhibited with several-hundredfold dilutions of mouse polyclonal sera obtained by immunization with live or heat-killed whole cells, suggesting that OmpA is one of the immunodominant antigens of serovar Typhimurium. All of the MAbs were specific for an identical epitope(s) located on the C-terminal domain of OmpA, as indicated by the use of OmpA fragments generated by protease or cyanogen bromide treatment and by competitive inhibition enzyme-linked immunosorbent assay. This epitope was highly conserved within (but not outside) the family Enterobacteriaceae: The strong immunogenicity of this epitope was surprising because the C-terminal domain of OmpA, usually thought to be located in the periplasm, is not expected to be exposed on the bacterial cell surface. A MAb, however, reacted in a cytofluorometry assay more strongly with outer-membrane-permeabilized cells than with untreated cells, a result supporting the predominantly periplasmic localization of the epitope. Significant, though low-level, reactivity of intact cells nevertheless suggests that in some cells the C-terminal domain of OmpA is exposed on the surface, a result consistent with the proposal that OmpA can fold into one of the two alternate conformations.