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Salt-inducible kinases (SIKs), a family of serine/threonine kinases, were found to be critical determinants of female fertility. SIK2 silencing results in increased ovulatory response to gonadotropins. In contrast, SIK3 knockout results in infertility, gonadotropin insensitivity, and ovaries devoid of antral and preovulatory follicles. This study hypothesizes that SIK2 and SIK3 differentially regulate follicle growth and fertility via contrasting actions in the granulosa cells (GCs), the somatic cells of the follicle. Therefore, SIK2 or SIK3 GC-specific knockdown (SIK2GCKD and SIK3GCKD, respectively) mice were generated by crossing SIK floxed mice with Cyp19a1pII-Cre mice. Fertility studies revealed that pup accumulation over 6 months and the average litter size of SIK2GCKD mice were similar to controls, although in SIK3GCKD mice were significantly lower compared to controls. Compared to controls, gonadotropin stimulation of prepubertal SIK2GCKD mice resulted in significantly higher serum estradiol levels, whereas SIK3GCKD mice produced significantly less estradiol. Cyp11a1, Cyp19a1, and StAR were significantly increased in the GCs of gonadotropin-stimulated SIK2GCKD mice. However, Cyp11a1 and StAR remained significantly lower than controls in SIK3GCKD mice. Interestingly, Cyp19a1 stimulation in SIK3GCKD was not statistically different compared to controls. Superovulation resulted in SIK2GCKD mice ovulating significantly more oocytes, whereas SIK3GCKD mice ovulated significantly fewer oocytes than controls. Remarkably, SIK3GCKD superovulated ovaries contained significantly more preantral follicles than controls. SIK3GCKD ovaries contained significantly more apoptotic cells and fewer proliferating cells than controls. These data point to the differential regulation of GC function and follicle development by SIK2 and SIK3 and supports the therapeutic potential of targeting these kinases for treating infertility or developing new contraceptives. [ABSTRACT FROM AUTHOR]

Gain-of-function mutations in the fibroblast growth factor receptor 3 gene (FGFR3) result in skeletal dysplasias, such as thanatophoric dysplasia and achondroplasia (ACH). The lack of disease models using human cells has hampered the identification of a clinically effective treatment for these diseases. Here we show that statin treatment can rescue patient--specific induced pluripotent stem cell (iPSC) models and a mouse model of FGFR3 skeletal dysplasia. We converted fibroblasts from thanatophoric dysplasia type I (TD1) and ACH patients into iPSCs. The chondrogenic differentiation of TD1 iPSCs and ACH iPSCs resulted in the formation of degraded cartilage. We found that statins could correct the degraded cartilage in both chondrogenically differentiated TD1 and ACH iPSCs. Treatment of ACH model mice with statin led to a significant recovery of bone growth. These results suggest that statins could represent a medical treatment for infants and children with TD1 and ACH., Achondroplasia (ACH) is the most common skeletal dysplasia, and the condition leads to disproportionate short-limb dwarfism. Mutations in the gene encoding fibroblast growth factor receptor 3 (FGFR3) were identified in [...]

Repair of cartilage injury with hyaline cartilage continues to be a challenging clinical problem. Because of the limited number of chondrocytes in vivo, coupled with in vitro de-differentiation of chondrocytes into fibro-chondrocytes, which secrete type I collagen and have an altered matrix architecture and mechanical function, there is a need for a novel cell source that produces hyaline cartilage. The generation of induced pluripotent stem (iPS) cells has provided a tool for reprogramming dermal fibroblasts to an undifferentiated state by ectopic expression of reprogramming factors. Here, we show that retroviral expression of two reprogramming factors (c-Myc and Klf4) and one chondrogenic factor (SOX9) induces polygonal chondrogenic cells directly from adult dermal fibroblast cultures. Induced cells expressed marker genes for chondrocytes but not fibroblasts, i.e., the promoters of type I collagen genes were extensively methylated. Although some induced cell lines formed tumors when subcutaneously injected into nude mice, other induced cell lines generated stable homogenous hyaline cartilage-like tissue. Further, the doxycycline-inducible induction system demonstrated that induced cells are able to respond to chondrogenic medium by expressing endogenous Sox9 and maintain chondrogenic potential after substantial reduction of transgene expression. Thus, this approach could lead to the preparation of hyaline cartilage directly from skin, without generating iPS cells., Introduction Hyaline cartilage sustains body growth as primordial cartilage and growth plate cartilage, and provides shock absorption and lubrication in diarthrodial joints as articular cartilage. Hyaline cartilage is a highly [...]

Recent advances in single-cell analysis technology have made it possible to analyse tens of thousands of cells at a time. In addition, sample multiplexing techniques, which allow the analysis of several types of samples in a single run, are very useful for reducing experimental costs and improving experimental accuracy. However, a problem with this technique is that antigens and antibodies for universal labelling of various cell types may not be fully available. To overcome this issue, we developed a universal labelling technique, Universal Surface Biotinylation (USB), which does not depend on specific cell surface proteins. By introducing biotin into the amine group of any cell surface protein, we have obtained good labelling results in all the cell types we have tested. Combining with DNA-tagged streptavidin, it is possible to label each cell sample with specific DNA 'hashtag'. Compared with the conventional cell hashing method, the USB procedure seemed to have no discernible adverse effect on the acquisition of the transcriptome in each cell, according to the model experiments using differentiating mouse embryonic stem cells. This method can be theoretically used for any type of cells, including cells to which the conventional cell hashing method has not been applied successfully. [ABSTRACT FROM AUTHOR]