Immunocytochemical detection and reverse transcription polymerase chain reaction expression of oncostatin M (OSM) and its receptor (OSM-Rbeta) in human fetal and adult ovaries

Oncostatin M: Risks and Benefits of a Novel Therapeutic Target for Atherosclerosis

BACKGROUND

Cardiovascular disease (CVD) is a leading cause of death worldwide. It is predicted that approximately 23.6 million people will die from CVDs annually by 2030. Therefore, there is a great need for an effective therapeutic approach to combat this disease. The European Cardiovascular Target Discovery (CarTarDis) consortium identified Oncostatin M (OSM) as a potential therapeutic target for atherosclerosis. The benefits of modulating OSM - an interleukin (IL)-6 family cytokine - have since been studied for multiple indications. However, as decades of high attrition rates have stressed, the success of a drug target is determined by the fine balance between benefits and the risk of adverse events. Safety issues should therefore not be overlooked.

OBJECTIVE

In this review, a risk/benefit analysis is performed on OSM inhibition in the context of atherosclerosis treatment. First, OSM signaling characteristics and its role in atherosclerosis are described. Next, an overview of in vitro, in vivo, and clinical findings relating to both the benefits and risks of modulating OSM in major organ systems is provided. Based on OSM's biological function and expression profile as well as drug intervention studies, safety concerns of inhibiting this target have been identified, assessed, and ranked for the target population.

CONCLUSION

While OSM may be of therapeutic value in atherosclerosis, drug development should also focus on de-risking the herein identified major safety concerns: tissue remodeling, angiogenesis, bleeding, anemia, and NMDA- and glutamate-induced neurotoxicity. Close monitoring and/or exclusion of patients with various comorbidities may be required for optimal therapeutic benefit.

Rescue IVM of Denuded GV- and MI-Stage Oocytes of Premenopausal Rats with Oncostatin M, Insulin-like Growth Factor I, and Growth Hormone

Immature oocytes are retrieved and matured through in vitro maturation (IVM). Maturation, fertilization rates, and embryo development via IVM are all lower than those found in vitro fertilization (IVF) cycles. We investigated the effects of oncostatin M (OSM), insulin-like growth factor-1 (IGF-I), and growth hormone (GH) in rescue IVM. A total of 111 germinal vesicle (GV) and 17 metaphase I (MI) oocytes were obtained after conventional IVF from 28 female Wistar albino rats. Denuded immature oocytes were cultured in maturation medium supplemented with OSM, IGF-1, or GH. The quantities of metaphase II (MII) oocytes matured from the GV stage were 17 of 30 (56.6%), 15 of 28 (53.5%), 10 of 30 (33.3%), and 7 of 23 (30.3%), in control, OSM, IGF-I, and GH groups, respectively. Maturation rates in control and OSM groups were higher than those in IGF-I and GH groups (p = 0.001). The quantities of MII oocytes matured from MI stage were 7 of 7 (100%), 4 of 4 (100%), 1 of 1 (100%), and 1 of 5 (20%) in control, OSM, IGF-I, and GH groups, respectively. Maturation rates from MI to MII stages in control, OSM, and IGF-I groups were higher than those in the GH group (p = 0.004). Acceptable maturation rates are observed with OSM in rat oocytes in rescue IVM.

Oncostatin M and its receptor in women with polycystic ovary syndrome and association with assisted reproductive technology outcomes

The role of adipokines in ovarian-related disorders such as polycystic ovary syndrome (PCOS) has been reported. However, the involvement of Oncostatin M (OSM), a recently identified adipokine, in ovarian function is unknown. Therefore, we investigated the association of the OSM signaling pathway with ovarian functions and PCOS pathogenesis. This case-control study enrolled 30 PCOS and 30 healthy women who underwent the intracytoplasmic sperm injection procedure. OSM and OSM receptor (OSMR) levels were evaluated in the follicular fluid (FF). Moreover, the expression of insulin receptor substrates (IRS1 and IRS2), OSM, OSMR, suppressor of cytokine signaling 3 (SOCS3), and androgen receptor (AR) genes were analyzed in the isolated cumulus cells (CCs). For the in-vitro experiment, the effect of recombinant OSM on the expression of related genes in isolated CCs was analyzed. Follicular concentrations of OSM and OSMR were significantly lower in PCOS (123.91±48.58 pg/ml and 0.93±0.35 ng/ml, respectively) compared to control women (283.53 ± 96.62 pg/ml and 1.45 ± 0.18 ng/ml, respectively; p < 0.001) and were positively correlated with the oocyte maturation (r = 0.611 and r = 0.611, respectively) and fertilization (r = 0.592 and r = 0.627, respectively) rates in the PCOS group. Furthermore, the SOCS3 expression was upregulated about eight times in PCOS patients compared to the controls (p < 0.05). The treatment of cells with recombinant OSM significantly increased SOCS3, OSMR, IRS-1, and -2 expression and decreased AR expression. The decreased levels of OSM and its receptor in PCOS patients, possibly mediated by SOCS3, could negatively affect oocyte maturation and fertilization rates.

Transcriptomics of cumulus cells - a window into oocyte maturation in humans

Background

Cumulus cells (CC) encapsulate growing oocytes and support their growth and development. Transcriptomic signatures of CC have the potential to serve as valuable non-invasive biomarkers for oocyte competency and potential. The present sibling cumulus-oocyte-complex (COC) cohort study aimed at defining functional variations between oocytes of different maturity exposed to the same stimulation conditions, by assessing the transcriptomic signatures of their corresponding CC. CC were collected from 18 patients with both germinal vesicle and metaphase II oocytes from the same cycle to keep the biological variability between samples to a minimum. RNA sequencing, differential expression, pathway analysis, and leading-edge were performed to highlight functional differences between CC encapsulating oocytes of different maturity.

Results

Transcriptomic signatures representing CC encapsulating oocytes of different maturity clustered separately on principal component analysis with 1818 genes differentially expressed. CCs encapsulating mature oocytes were more transcriptionally synchronized when compared with CCs encapsulating immature oocytes. Moreover, the transcriptional activity was lower, albeit not absent, in CC encapsulating mature oocytes, with 2407 fewer transcripts detected than in CC encapsulating immature (germinal vesicle - GV) oocytes. Hallmark pathways and ovarian processes that were affected by oocyte maturity included cell cycle regulation, steroid metabolism, apoptosis, extracellular matrix remodeling, and inflammation.

Conclusions

Herein we review our findings and discuss how they align with previous literature addressing transcriptomic signatures of oocyte maturation. Our findings support the available literature and enhance it with several genes and pathways, which have not been previously implicated in promoting human oocyte maturation. This study lays the ground for future functional studies that can enhance our understanding of human oocyte maturation.

Distinct DNA Methylation Profiles in Ovarian Tumors: Opportunities for Novel Biomarkers

Aberrant methylation of multiple promoter CpG islands could be related to the biology of ovarian tumors and its determination could help to improve treatment strategies. DNA methylation profiling was performed using the Methylation Ligation-dependent Macroarray (MLM), an array-based analysis. Promoter regions of 41 genes were analyzed in 102 ovarian tumors and 17 normal ovarian samples. An average of 29% of hypermethylated promoter genes was observed in normal ovarian tissues. This percentage increased slightly in serous, endometrioid, and mucinous carcinomas (32%, 34%, and 45%, respectively), but decreased in germ cell tumors (20%). Ovarian tumors had methylation profiles that were more heterogeneous than other epithelial cancers. Unsupervised hierarchical clustering identified four groups that are very close to the histological subtypes of ovarian tumors. Aberrant methylation of three genes (BRCA1, MGMT, and MLH1), playing important roles in the different DNA repair mechanisms, were dependent on the tumor subtype and represent powerful biomarkers for precision therapy. Furthermore, a promising relationship between hypermethylation of MGMT, OSMR, ESR1, and FOXL2 and overall survival was observed. Our study of DNA methylation profiling indicates that the different histotypes of ovarian cancer should be treated as separate diseases both clinically and in research for the development of targeted therapies.

Stimulation of the JAK/STAT pathway by LIF and OSM in the human granulosa cell line COV434

The development of the follicle and competent oocyte is highly coordinated, requiring interplay among several systems. These implicate endocrine, immune, and metabolic signals, intrafollicular paracrine factors from theca, mural, and cumulus granulosa cells, and the oocyte itself. Granulosa cells play a key role in their interaction. COV434 is one of the few human granulosa cell lines that can be used as an in vitro model for ovarian research. We aimed to evaluate the possible activation of the Janus kinase/signal transducers and activators of transcription (JAK/STAT) signaling pathway by IL-6-type cytokines leukemia inhibitory factor (LIF) and oncostatin M (OSM) in COV434 cells. Expression of GP130 (glycoprotein 130), STAT3 (signal transducer and activators of transcription 3), PIAS3 (protein inhibitor of activated STAT 3), and SOCS3 (suppressor of cytokine signaling 3) genes after stimulation with LIF or OSM was assessed using RT-qPCR (real-time PCR). GP130 transcripts were significantly upregulated after incubation with LIF or OSM for 24h. Expression of the STAT3 gene was stimulated only after incubation with LIF, but not OSM. SOCS3 showed significant upregulation for all time periods and the levels of PIAS3 were initially down- and after 24h upregulated. Furthermore, the major signaling components of the JAK/STAT pathway, GP130 and STAT3, and the kinase activation patterns of STAT3, were examined at protein level. We found constitutive protein expression for GP130, STAT3, pSTAT3(ser727) and upregulation of pSTAT3(tyr705) by LIF and OSM. Our results demonstrate the activation of the JAK/STAT pathway by LIF and OSM in human granulosa cells.