Immunolocalisation and expression of Smad2 and Smad4 proteins in dog testis during postnatal development

SMAD2 regulates testicular development and testosterone synthesis in Hu sheep

The SMAD protein family plays crucial roles in reproduction as a downstream target genes of the TGFβ signaling pathway. Many studies have focused on the expression change exploration of SMADs during testicular development and investigation of SMAD2 in hormone synthesis regulation. However, little attention has been given to determining the regulatory mechanism of SMADs in sheep testes. In the present study, we first detected SMAD mRNA expression levels in three-month-old (3 M), six-month-old (6 M), nine-month-old (9 M) and two-year-old (2Y) sheep testes. Different SMADs showed various expression patterns. In addition, the subcellular localization of SMAD2 was also analyzed, and Sertoli cells (SCs), Leydig cells (LCs) and spermatogonia presented mainly positive staining. Protein and nucleic acid sequence alignment showed that the SMAD2 gene was extremely homologous between various species. SMAD2 interference RNA was transfected into sheep LCs to examine the cell proliferation and hormone levels. The testosterone level was significantly decreased, and cell proliferation efficiency presented the same trend (P < 0.05). Moreover, SMAD2 downregulation promoted cell apoptosis (P < 0.05) and changed the cell cycle. In total, our results revealed that downregulating the expression of SMAD2 can effectively inhibit testosterone levels by affecting cell proliferation and apoptosis.

Differential expression of microRNAs in sexually immature and mature canine testes

Mammalian testis exhibits spatiotemporal gene expression patterns that are essential for successful and continuous spermatogenesis. Although microRNAs (miRNAs) modify gene expression through translational repression and degradation of target messenger RNAs, the precise molecular mechanisms of these regulatory processes are unclear. We used canine miScript miRNA polymerase chain reaction (PCR) Array technology to elucidate the repertoire of canine testis miRNAs and compared their expression patterns between sexually immature (prepubertal) and mature (adult) dog testes. Eighty-four well-characterized canine miRNAs were customized in this study. The data were analyzed by RT(2) Profiler PCR Array Data Analysis (version 3.5). Results identified upregulation of 32 and considerable downregulation of 12 miRNAs in adult dog testis. In conclusion, the two developmental stages had significantly different miRNAs expression patterns. The finding provides fundamental information of miRNAs which may help to elucidate their role in spermatogenesis and male infertility in this species. To the best of our knowledge, this study is the first to offer comparative profile of the miRNA transcriptome in prepubertal and adult canine testes using miRNA PCR array approach.

Identification and biological characterization of chicken embryonic cardiac progenitor cells

OBJECTIVES

Many kinds of cardiac progenitor cell populations have been identified, including c-kit(+) , Nkx2.5(+) s and GATA4(+) cells. However, these progenitors have limited ability to differentiate into different cardiac cell types. Recently, a new kind of cardiac progenitor cell named the multipotent Isl1(+) cardiovascular progenitor (MICPs) has been identified, which also expresses Nkx2.5, GATA4, CD34 and Flk1.

MATERIALS AND METHODS

In this study, we have isolated and characterized MICPs from chicken embryonic heart tissues using immunofluorescence and PCR.

RESULTS

Results shown that they express markers of cardiac progenitor cells, with high clonality. They have the ability to self-renew and can give rise to three types of heart cell in vitro.

CONCLUSIONS

Myocytes, smooth muscle cells and endothelial cells. Our work provides evidence for a developmental paradigm of the heart, that endothelial and muscle lineage diversification arises from multipotent cardiac progenitor cells. Existence of these cells provides a new opportunity for myocardial injury repair.

Isolation and biological characterization of chicken amnion epithelial cells

Amniotic epithelial cells (AECs) express Oct4, Nanog and Sox-2, which are necessary for maintaining the undifferentiated state of pluripotent stem cells. AECs additionally express CK19, which is a specific marker of epithelial cells, both in vivo and in vitro. In this research, we investigated the biological characteristics and potential for cell therapy of AECs from 6-day-old chicken embryos. We induced the AECs to differentiate into pancreatic islet-like cells (endoderm), adipocytes and osteoblasts (mesoderm) and neural-like cells (ectoderm), and used immunofluorescence and RT-PCR to detect the expression of AECs specific markers. To assess the differentiation capacity of AECs, passage 3 cells were induced to differentiate into adipocytes, osteoblasts, pancreatic islet-like cells and neural-like cells. The AEC markers, Oct-4, Nanog, Sox-2 and CK19, were all positively expressed. Cloning efficiency decreased with increasing passage number. Passage 3 AECs were successfully induced to differentiate into pancreatic islet-like cells, osteoblasts, adipocytes, and neural-like cells. These results suggested that AECs isolated from chicken embryos exhibited the characteristics of the multipotent stem cells. AECs may therefore be ideal candidates for cellular transplantation therapy and tissue engineering.