Up-regulation of Melanophilin (MLPH) gene during avian adipogenesis and decreased fat pad weights with adipocyte hypotrophy in MLPH knockout quail

Advanced genetic and nutritional strategies aimed at modulating fat deposition can significantly reduce production costs and enhance profitability in the poultry industry. Melanophilin (MLPH) is recognized as a key gene regulating pigmentation as shown by diluted hair and feather coloration in MLPH mutant animals, including avian models. However, the effects of MLPH during fat accretion have not been studied yet. Therefore, the objectives of the current study are to measure the temporal expression of the MLPH gene during the adipocyte differentiation in vitro and in vivo and to investigate the effect of MLPH loss on fat accretion and adipocyte sizes in vivo using MLPH knockout quail model. The current in vitro studies reveal that MLPH gene expression levels were considerably elevated during adipogenesis in avian cells [101-fold in DF-1, 28.5-fold in chicken embryonic fibroblasts (CEF) and 4-fold in quail embryonic fibroblasts (QEF), compared to the undifferentiated cells of each cell type, p < 0.05]. In addition, fractionated fat cells (FC) showed increased expression levels of MLPH (5.7-fold, p < 0.05) compared to stromal-vascular cells (SVC). Using the MLPH knockout quail, disruption of the MLPH gene resulted in significantly reduced body weight (BW) and subcutaneous fat (S. Fat) pad weights compared to the wild type (WT) (p < 0.05). Further analysis through sectioning and staining of the fat tissues revealed that the mutation in Rab binding domain (RBD) of quail MLPH resulted in decreased fat cell sizes (p < 0.01). Overall, our data clearly demonstrated that MLPH can be a potential adipogenic marker gene, and MLPH may be associated with fat accretion in the gene edited quail model, highlighting the important role of MLPH in adipogenesis.