Differential expression of lysosome-associated protein transmembrane-4 beta (LAPTM4B) in granulosa cells of ovarian follicles and in other bovine tissues

Janus Kinase 3 phosphorylation and the JAK/STAT pathway are positively modulated by follicle-stimulating hormone (FSH) in bovine granulosa cells

Janus kinase 3 (JAK3) is a member of the JAK family of tyrosine kinase proteins involved in cytokine receptor-mediated intracellular signal transduction through the JAK/STAT signaling pathway. JAK3 was previously shown as differentially expressed in granulosa cells (GC) of bovine pre-ovulatory follicles suggesting that JAK3 could modulate GC function and activation/inhibition of downstream targets. We used JANEX-1, a JAK3 inhibitor, and FSH treatments and analyzed proliferation markers, steroidogenic enzymes and phosphorylation of target proteins including STAT3, CDKN1B/p27^Kip1 and MAPK8IP3/JIP3. Cultured GC were treated with or without FSH in the presence or not of JANEX-1. Expression of steroidogenic enzyme CYP11A1, but not CYP19A1, was upregulated in GC treated with FSH and both were significantly decreased when JAK3 was inhibited. Proliferation markers CCND2 and PCNA were reduced in JANEX-1-treated GC and upregulated by FSH. Western blots analyses showed that JANEX-1 treatment reduced pSTAT3 amounts while JAK3 overexpression increased pSTAT3. Similarly, FSH treatment increased pSTAT3 even in JANEX-1-treated GC. UHPLC-MS/MS analyses revealed phosphorylation of specific amino acid residues within JAK3 as well as CDKN1B and MAPK8IP3 suggesting possible activation or inhibition post-FSH or JANEX-1 treatments. We show that FSH activates JAK3 in GC, which could phosphorylate target proteins and likely modulate other signaling pathways involving CDKN1B and MAPK8IP3, therefore controlling GC proliferation and steroidogenic activity.

Integrative Genome-Wide DNA Methylome and Transcriptome Analysis of Ovaries from Hu Sheep with High and Low Prolific

DNA methylation plays an important role in biological processes by affecting gene expression. However, how DNA methylation regulates phenotypic variation in Hu sheep remains unclear. Therefore, we generated genome-wide DNA methylation and transcriptomic profiles in the ovaries of Hu sheep with different prolificacies and genotypes (FecBB and FecB+). Results showed that ovary DNA methylome and transcriptome were significantly different between high prolificacy and low prolificacy Hu sheep. Comparative methylome analyses identified 10,644, 9,594, and 12,214 differentially methylated regions and 87, 1,121, and 2,375 genes, respectively, showing differential expression levels in three different comparison groups. Female reproduction-associated differentially methylated regions-related genes and differentially expressed genes were enriched, thereby the respective interaction networks were constructed. Furthermore, systematical integrative analyses revealed a negative correlation between DNA methylation around the transcriptional start site and gene expression levels, which was confirmed by testing the expression of integrin β2 subunit (ITGB2) and lysosome-associated protein transmembrane-4 beta (LAPTM4B) in vivo and in vitro. These findings demonstrated that DNA methylation influences the propensity for prolificacy by affecting gene expression in the ovaries, which may contribute to a greater understanding of the epigenome and transcriptome that will be useful for animal breeding.

Two alternative methods for the retrieval of somatic cell populations from the mouse ovary

Many modern techniques employed to uncover the molecular fundamentals underlying biological processes require dissociated cells as their starting point/substrate. Investigations into ovarian endocrinology or folliculogenesis, therefore, necessitate robust protocols for dissociating the ovary into its constituent cell populations. While in the mouse, methods to obtain individual, mature follicles are well-established, the separation and isolation of single cells of all types from early mouse follicles, including somatic cells, has been more challenging. Herein we present two methods for the isolation of somatic cells in the ovary. These methods are suitable for a range of applications relating to the study of folliculogenesis and mouse ovarian development. First, an enzymatic dissociation utilising collagenase and a temporary, primary cell culture step using neonatal mouse ovaries which yields large quantities of granulosa cells from primordial, activating, and primary follicles. Second, a rapid papain dissociation resulting in a high viability single cell suspension of ovarian somatic cells in less than an hour, which can be applied from embryonic to adult ovarian samples. Collectively these protocols can be applied to a broad array of investigations with unique advantages and benefits pertaining to both.

Identification of Lysosome-Associated Protein Transmembrane-4 as a Novel Therapeutic Target for Osteosarcoma Treatment

OBJECTIVE

The aim of the study is to evaluate the expression of lysosome-associated protein transmembrane-4 (LAPTM4B) in human osteosarcoma tissue samples collected in our hospital, and to explore the possible correlations between the clinical pathological features of osteosarcoma patients and LAPTM4B expression.

METHODS

Immunohistochemical (IHC) assays were performed to detect the expression levels of LAPTM4B in 62 tissue samples of osteosarcoma tissues and corresponding non-tumor tissues. According to LAPTM4B staining intensity in tumor tissues, osteosarcoma patients were classified into LAPTM4B high expression and low expression groups. In addition, the potential correlations between LAPTM4B expression levels and clinical pathological features were evaluated. In addition, we detected the effects of LAPTM4B on the proliferation and invasion of esteosarcoma cells through colony formation assay and transwell assay, respectively. We further explored the potential effects of LAPTM4B on tumor growth and metastasis using in vivo animal model.

RESULTS

We revealed that LAPTM4B was highly expressed in human osteosarcoma tissues. We determined the significance between LAPTM4B and clinical features, including the tumor size (P = 0.004*) and the clinical stage (P = 0.035*) of osteosarcoma patients. Our results further demonstrated that ablation of LAPTM4B obviously blocked the proliferation and invasion of osteosarcoma cells in vitro and restrained tumor growth and metastasis in mice.

CONCLUSION

We investigated the potential involvement of LAPTM4B in osteosarcoma progression and confirmed LAPTM4B as a novel therapeutic target for osteosarcoma.

Functional effects of Tribbles homolog 2 in bovine ovarian granulosa cells†

Tribbles homologs (TRIB) 1, 2, and 3 represent atypical members of the serine/threonine kinase superfamily. We previously identified TRIB2 as a differentially expressed gene in granulosa cells (GCs) of bovine preovulatory follicles. The current study aimed to further investigate TRIB2 regulation and study its function in the ovary. GCs were collected from follicles at different developmental stages: small antral follicles (SF), dominant follicles (DF) at day 5 of the estrous cycle, and hCG-induced ovulatory follicles (OFs). RT-qPCR analyses showed greater expression of TRIB2 in GC of DF as compared to OF and a significant downregulation of TRIB2 steady-state mRNA amounts by hCG/LH, starting at 6 h through 24 h post-hCG as compared to 0 h. Specific anti-TRIB2 polyclonal antibodies were generated and western blot analysis confirmed TRIB2 downregulation by hCG at the protein level. In vitro studies showed that FSH stimulates TRIB2 expression in GC. Inhibition of TRIB2 using CRISPR/Cas9 resulted in a significant increase in PCNA expression and an increase in steroidogenic enzyme CYP19A1 expression, while TRIB2 overexpression tended to decrease GC proliferation. TRIB2 inhibition also resulted in a decrease in transcription factors connective tissue growth factor (CTGF) and ankyrin repeat domain-containing protein 1 (ANKRD1) expression, while TRIB2 overexpression increased CTGF and ANKRD1. Additionally, western blot analyses showed reduction in ERK1/2 (MAPK3/1) and p38MAPK (MAPK14) phosphorylation levels following TRIB2 inhibition, while TRIB2 overexpression increased p-ERK1/2 and p-p38MAPK. These results provide evidence that TRIB2 modulates MAPK signaling in GC and that TRIB2 could act as a regulator of GC proliferation and function, which could affect steroidogenesis during follicular development.

Gonadotropin regulation of ankyrin-repeat and SOCS-box protein 9 (ASB9) in ovarian follicles and identification of binding partners

Ankyrin-repeat and SOCS-box protein 9 (ASB9) is a member of the large SOCS-box containing proteins family and acts as the specific substrate recognition component of E3 ubiquitin ligases in the process of ubiquitination and proteasomal degradation. We previously identified ASB9 as a differentially expressed gene in granulosa cells (GC) of bovine ovulatory follicles. This study aimed to further investigate ASB9 mRNA and protein regulation, identify binding partners in GC of bovine ovulatory follicles, and study its function. GC were obtained from small follicles (SF: 2–4 mm), dominant follicles at day 5 of the estrous cycle (DF), and ovulatory follicles, 24 hours following hCG injection (OF). Analyses by RT-PCR showed a 104-fold greater expression of ASB9 in GC of OF than in DF. Steady-state levels of ASB9 in follicular walls (granulosa and theca cells) analyzed at 0, 6, 12, 18 and 24 hours after hCG injection showed a significant induction of ASB9 expression at 12 and 18 hours, reaching a maximum induction of 10.2-fold at 24 hours post-hCG as compared to 0 hour. These results were confirmed in western blot analysis showing strongest ASB9 protein amounts in OF. Yeast two-hybrid screening of OF-cDNAs library resulted in the identification of 10 potential ASB9 binding partners in GC but no interaction was found between ASB9 and creatine kinase B (CKB) in these GC. Functional studies using CRISPR-Cas9 approach revealed that ASB9 inhibition led to increased GC proliferation and modulation of target genes expression. Overall, these results support a physiologically relevant role of ASB9 in the ovulatory follicle by targeting specific proteins likely for degradation, contributing to reduced GC proliferation, and could be involved in the final GC differentiation into luteal cells.