Human pluripotent stem cell-derived cells endogenously expressing follicle-stimulating hormone receptors: modeling the function of an inactivating receptor mutation.

Follicle-stimulating hormone (FSH) is crucial in the development and regulation of reproductive functions. The actions of human FSH and its receptor (FSHR) and mutations therein have mainly been studied using in vivo models, primary cells, cancer cells and cell lines ectopically expressing the FSHR. To allow studies of endogenous FSHR function in vitro, we differentiated FSHR-expressing cells from human pluripotent stem cells. FSH stimulation of the wild-type (WT), but not the inactivating Finnish founder mutant (A189V) receptor, activated the canonical cyclic adenosine monophosphate (cAMP)-dependent signaling pathway and downstream mediators. To investigate protein-protein interaction partners of FSHR at resting state and upon FSH stimulation, we expressed FSHR in HEK293 cells followed by affinity purification mass spectrometry analyses. We found 19 specific high-confidence interacting proteins for WT FSHR and 14 for A189V FSHR, several of which have been linked to infertility. Interestingly, while only WT FSHR interacted with FSH, insulin-like growth factor 1 receptor (IGF1R), for example, interacted with both WT and A189V FSHR upon FSH stimulation. In conclusion, our protocol allows detailed studies of FSH action and disease modeling in human cells endogenously expressing FSHR.

Pool-seq driven proteogenomic database for Group G Streptococcus.

Proteogenomic databases use genomic and transcriptomic information for improved identification of peptides and proteins from mass spectrometry analyses. One application of such databases is in the discovery of variants/mutations. In this study, we created a proteogenomic database that contained sequences with variants derived from Pooled sequencing experiments (137 Group G Streptococcus strains sequenced in 3 pools) and used tandem mass spectrometry (MS/MS) to analyse eight protein samples from randomly selected strains sequenced in the pools. Using the proteogenomic variant database, we identified 385 variant peptides from the eight samples, none of which could be identified from the single genome conventional database utilized, while 71.2% and 93.5% of them were identified from the databases that contained 4 complete genomes and 26 assemblies, respectively. The proteogenomic variant databases exhibited the same properties as the conventional databases in terms of the Andromeda score distributions and the posterior error probability (PEP) values of the identified peptides. SIGNIFICANCE: For bacterial populations, such as Group G Streptococcus (GGS), with substantial intra-species diversity, simultaneous sequencing of large numbers of strains and generation of proteogenomic databases from those aids in improving the discovery of peptides in mass spectrometric analyses. Therefore, generation of proteogenomic variant protein databases from Pooled sequencing experiments can be a cost-effective method to complement conventional databases and discover subtle strain wise differences.

Gremlin-1 associates with fibrillin microfibrils in vivo and regulates mesothelioma cell survival through transcription factor slug.

Malignant mesothelioma is a form of cancer that is highly resistant to conventional cancer therapy for which no major therapeutic advances have been introduced. Here, we identify gremlin-1, a known bone morphogenetic protein inhibitor crucial for embryonic development, as a potential therapeutic target for mesothelioma. We found high expression levels of gremlin-1 in the mesothelioma tumor tissue, as well as in primary mesothelioma cells cultured from pleural effusion samples. Downregulation of gremlin-1 expression by siRNA-mediated silencing in a mesothelioma cell line inhibited cell proliferation. This was associated with downregulation of the transcription factor slug as well as mesenchymal proteins linked to cancer epithelial-to-mesenchymal transition. Further, resistance to paclitaxel-induced cell death was associated with high gremlin-1 and slug expression. Treatment of gremlin-1-silenced mesothelioma cells with paclitaxel or pemetrexed resulted in efficient loss of cell survival. Finally, our data suggest that concomitant upregulation of fibrillin-2 in mesothelioma provides a mechanism for extracellular localization of gremlin-1 to the tumor microenvironment. This was supported by the demonstration of interactions between gremlin-1, and fibrillin-1 and -2 peptides as well as by colocalization of gremlin-1 to fibrillin microfibrils in cells and tumor tissue samples. Our data suggest that gremlin-1 is also a potential target for overcoming drug resistance in mesothelioma.