Particular Role of JAK/STAT3 Signaling in Functional Control of Mesenchymal Progenitor Cells

JAK/STAT3 pathway promotes proliferation of ovarian aggregate-derived stem cells in vitro

BACKGROUND

The accurate identification and isolation of ovarian stem cells from mammalian ovaries remain a major challenge because of the lack of specific surface markers and suitable in vitro culture systems. Optimized culture conditions for in vitro expansion of ovarian stem cells would allow for identifying requirements of these stem cells for proliferation and differentiation that would pave the way to uncover role of ovarian stem cells in ovarian pathophysiology. Here, we used three-dimensional (3D) aggregate culture system for enrichment of ovarian stem cells and named them aggregate-derived stem cells (ASCs). We hypothesized that mimicking the ovarian microenvironment in vitro by using an aggregate model of the ovary would provide a suitable niche for the isolation of ovarian stem cells from adult mouse and human ovaries and wanted to find out the main cellular pathway governing the proliferation of these stem cells.

RESULTS

We showed that ovarian aggregates take an example from ovary microenvironment in terms of expression of ovarian markers, hormone secretion and supporting the viability of the cells. We found that aggregates-derived stem cells proliferate in vitro as long-term while remained expression of germline markers. These ovarian stem cells differentiated to oocyte like cells in vitro spontaneously. Transplantation of these stem cells in to chemotherapy mouse ovary could restore ovarian structure. RNA-sequencing analysis revealed that interleukin6 is upregulated pathway in ovarian aggregate-derived stem cells. Our data showed that JAK/Stat3 signaling pathway which is activated downstream of IL6 is critical for ovarian stem cells proliferation.

CONCLUSIONS

We developed a platform that is highly reproducible for in vitro propagation of ovarian stem cells. Our study provides a primary insight into cellular pathway governing the proliferation of ovarian stem cells.

Specific Features of Intracellular Signal Transduction in the Regulation of Functions of Neural Stem Cells and Committed Neuronal Progenitors

We studied the role of NF-κB-, cAMP/PKA-, JAKs/STAT3-, ERK1/2-, p38-, JNK- and p53- mediated signaling pathways in the realization of the growth potential of neural stem cells and committed neuronal progenitors under in vitro conditions. The method of pharmacological blockade with selective inhibitors of individual signaling molecules revealed some principal differences in their role in the determination of the proliferation and differentiation status of progenitor cells of different classes. Analysis of the peculiarities of intracellular signaling in cells and comparison of the role of its individual elements attest to the prospects of developing new drugs with neuroregenerative activity based on STAT3 inhibitors or JNK activators. These modulations of activity of signaling molecules can stimulate the realization of the growth potential of committed neuronal progenitors and neutral stem cells, respectively. The blockade of STAT3 and an increase in the content of phosphorylated forms of JNK had no "negative" effects on the functioning of multipotent neural stem cells and committed neuronal progenitors, respectively.

TMEM119 promotes gastric cancer cell migration and invasion through STAT3 signaling pathway

Objective

TMEM119 is a member of transmembrane proteins family, which is abnormally expressed in human cancers and associated with tumorigenesis. In this study, we focused on the expression of TMEM119 and its role in cell invasion and migration in gastric cancer.

Methods

Real-time polymerase chain reaction, Western blotting, and immunohistochemistry were performed to examine the expression of TMEM119 in gastric cancer tissues and cell lines. After transfection with TMEM119 siRNA or recombined TMEM119-expressing vector, the invasion and migration ability of MKN45 and SGC-7901 cells was measured by transwell assay. The expression of TMEM119, p-STAT3, STAT3, VEGF, MMP2, and MMP9 proteins in SGC-7901 and MKN45 cells treated with TMEM119 siRNA, TMEM119-expressing vector, or AG490 was measured by Western blotting.

Results

We found that higher TMEM119 expression was found in gastric cancer tissues and cell lines and was associated with lower survival rate. TMEM119 knockdown inhibited SGC-7901 cell invasion and migration, along with the expression of p-STAT3, VEGF, MMP2, and MMP9. TMEM119 overexpression promoted MKN45 cell invasion and migration, along with the expression of p-STAT3, VEGF, MMP2, and MMP9. Additionally, AG490 treatment significantly corrected TMEM119-induced MKN45 cell migration and invasion and expression of p-STAT3, VEGF, MMP9, and MMP2 proteins.

Conclusion

The results indicated that TMEM119 promotes gastric cancer cell migration and invasion through activation of STAT3 signaling pathway, and TMEM119 may therefore act as a novel therapeutic target for gastric cancer.

Role of JAK/STAT3 Signaling in Functional Stimulation of Mesenchymal Progenitor Cells by Fibroblast Growth Factor

JAK/STAT signaling pathway was examined during functional stimulation of mesenchymal progenitor cells with fibroblast growth factor. The differences were observed in the realizations of the proliferation-differentiation potential of CFU-fibroblasts under blockade of JAKs or during selective inactivation of STAT3. The study revealed stimulating influences of JAKs and STAT3 on mitotic activity of progenitor cells and individual roles of these proteins in the control of their maturation. Blockade of JAKs diminished the level of fibroblast colony formation and the score of actively proliferating CFU-fibroblasts at the background increase of the differentiation rate of progenitor cells. In contrast, STAT3 inhibitor resulted in a coordinated decrease of all examined parameters.