Pathways involved in pony body size development

Abstract

Background The mechanism of body growth in mammals is poorly understood. Here, we investigated the regulatory networks involved in body growth through transcriptomic analysis of pituitary and epiphyseal tissues of smaller sized Debao ponies and Mongolian horses at the juvenile and adult stages. Results We found that growth hormone receptor (GHR) was expressed at low levels in long bones, although growth hormone (GH) was highly expressed in Debao ponies compared with Mongolian horses. Moreover, significant downregulated of the GHR pathway components m-RAS and ATF3 was found in juvenile ponies, which slowed the proliferation of bone osteocytes. However, WNT2 and PLCβ2 were obviously upregulated in juvenile Debao ponies, which led to premature mineralization of the bone extracellular matrix. Furthermore, we found that the WNT/Ca2+ pathway may be responsible for regulating body growth. GHR was demonstrated by q-PCR and Western blot analyses to be expressed at low levels in long bones of Debao ponies. Treatment with WNT antagonistI decreased the expression of WNT pathway components (P < 0.05) in vitro. Transduction of ATDC5 cells with a GHR-RNAi lentiviral vector decreased the expression of the GHR pathway components (P < 0.05). Additionally, the expression of the IGF-1 gene in the liver was lower in Debao ponies than in Mongolian horses at the juvenile and adult stages. Detection of plasma hormone concentrations showed that Debao ponies expressed higher levels of IGF-1 as juveniles and higher levels of GH as adults than Mongolian horses, indicating that the hormone regulation in Debao ponies differs from that in Mongolian horses. Conclusion Our work provides insights into the genetic regulation of short stature growth in mammals and can provide useful information for the development of therapeutic strategies for small size.

Variations in the fecal microbiota and their functions of Thoroughbred, Mongolian, and Hybrid horses

“…As an important breed in northern China, Mongolian horses have rich genomic diversity ( 21 ) and have a variety of excellent traits, such as adaptability, cold resistance, roughage resistance, disease resistance, and good stamina ( 22 , 23 ). Thoroughbred horses, a horse species bred in 17th-century Britain, were manually selected to meet the desired conditions of speed, temperament, and body size ( 24 ).…”

Genome-Wide Detection for Runs of Homozygosity in Baoshan Pigs Using Whole Genome Resequencing

“…DLX5, DKK1 and WNT2 are mainly enriched in the WNT signaling pathway and are involved in bone production, renewal and healing by regulating the expression of osteogenic coregulators, which are capable of influencing body size and thoracic vertebrae number in pigs. [55][56][57][58][59]. BS pigs are classified as large, medium, or small, probably due to differences in the expression and regulatory effects of osteogenic genes that differentiate their body sizes.…”

Genome-Wide Detection of Copy Number Variations Associated with Miniature Features in Horses

“…By downregulating the MAPK signaling cascade, GHR may reduce Debao horse height. The candidate genes Sox9 and Sox11 were found to promote the early occurrence of bio mineralization and epiphyseal closure in Debao ponies [51]. The candidate gene ADAMTS15 is associated with muscle development, such as myoblast fusion in thoroughbred horses [69].…”

“…The genes MRas and ATF3 in the GHR shed light on the genetics of the Debao pony of small stature. To understand the genetic basis of short size, genes such as ECM, ALPL, IHH, MMP23, TIMP4, COL10A1, Sox9, Sox6, Sox8, Sox11, COL2A1, and COL9A1 have been identified in the juvenile stage of the Debao horse [51]. A recent study showed that the genes TBX3, TBX5, and HMGA2 play a role in the genetic underpinnings of Chinese pony dwarfism [52].…”