Impact of fibronectin type III domain-containing family in the changes in metabolic and hormonal profiles during peripartum period in dairy cows

Exercise-induced muscle hormone "irisin" controls luteinizing hormone and follicle-stimulating hormone secretion by bovine gonadotrophs

Irisin is a hormone secreted by muscle in response to exercise. The irisin receptor (IrisinR) is a heterodimer of integrin alpha V (ITGAV) and integrin beta 5 (ITGB5) subunits. Since irisin may mediate some beneficial effects of exercise on animal reproduction, we tested the hypothesis that bovine gonadotrophs express IrisinR and irisin stimulates luteinizing hormone (LH) and follicle stimulating hormone (FSH) secretion by gonadotrophs. Reverse transcription polymerase chain reaction was used to detect the mRNA expression of both ITGAV and ITGB5 in the anterior pituitary glands (APs) of post pubertal heifers and mouse gonadotroph cell line "LβT2." Western blotting was used to detect protein expression in bovine APs. Immunofluorescence microscopy, utilizing the same antibody, visualized IrisinR on the plasma membrane of majority of gonadotrophs. We prepared AP cells from healthy postpubertal heifers, cultured them for 3.5 d, and treated them with increasing concentrations (0, 0.01, 0.1, 1, or 10 nM) of irisin for 5 min before either no treatment or gonadotropin-releasing hormone (GnRH) stimulation. After 2 h, media were harvested for LH and FSH assays. Irisin (0.1-10 nM) stimulated basal LH and FSH secretion, and these stimulatory effects were inhibited by the extracellular signal-regulated kinase or SMAD pathway inhibitors. In the presence of GnRH, irisin at 0.01-1 nM stimulated LH and FSH secretion. A higher dose of irisin (10 nM), however, suppressed the GnRH-induced LH and FSH levels. In conclusion, bovine gonadotrophs expressed IrisinR, and irisin controlled LH and FSH secretion from bovine gonadotrophs.

Irisin in domestic animals

Irisin is a 112 amino acid peptide hormone cleaved from the fibronectin type III domain-containing protein. Irisin is highly conserved across vertebrates, suggesting evolutionarily conserved common functions among domestic animals. These functions include the browning of white adipose tissue and increased energy expenditure. Irisin has been detected and studied primarily in plasma, serum, and skeletal muscle, but has also been found in adipose tissue, liver, kidney, lungs, cerebrospinal fluid, breast milk, and saliva. This wider tissue presence of irisin suggests additional functions beyond its role as a myokine in regulating energy use. We are beginning to understand irisin in domestic animals. The goal of this review is to provide an up-to-date commentary on irisin structure, tissue distribution, and functions across vertebrates, especially mammals of importance in veterinary medicine. Irisin could be explored as a potential candidate for developing therapeutic agents and biomarkers in domestic animal endocrinology.

Bioprinting of 3D Adipose Tissue Models Using a GelMA-Bioink with Human Mature Adipocytes or Human Adipose-Derived Stem Cells

Adipose tissue is related to the development and manifestation of multiple diseases, demonstrating the importance of suitable in vitro models for research purposes. In this study, adipose tissue lobuli were explanted, cultured, and used as an adipose tissue control to evaluate in vitro generated adipose tissue models. During culture, lobule exhibited a stable weight, lactate dehydrogenase, and glycerol release over 15 days. For building up in vitro adipose tissue models, we adapted the biomaterial gelatin methacryloyl (GelMA) composition and handling to homogeneously mix and bioprint human primary mature adipocytes (MA) and adipose-derived stem cells (ASCs), respectively. Accelerated cooling of the bioink turned out to be essential for the homogeneous distribution of lipid-filled MAs in the hydrogel. Last, we compared manual and bioprinted GelMA hydrogels with MA or ASCs and the explanted lobules to evaluate the impact of the printing process and rate the models concerning the physiological reference. The viability analyses demonstrated no significant difference between the groups due to additive manufacturing. The staining of intracellular lipids and perilipin A suggest that GelMA is well suited for ASCs and MA. Therefore, we successfully constructed physiological in vitro models by bioprinting MA-containing GelMA bioinks.