Project description:The Chinese forest musk deer (FMD; Moschus berezovskii) is an endangered artiodactyl mammal. Musk secreted by the musk gland of male FMD has extremely high economic and medicinal value. At present, little is known about the development of musk glands and the molecular mechanism of musk secretion. In the present research, using snRNA-seq and snATAC-seq association analysis performed on musk glands of forest musk deer, coupled with several bioinformatics analyses, the dynamic transcriptional cell atlas of musk gland development was revealed and the genes and transcription factors affecting musk secretion were determined. Based on uniform manifold approximation and projection (UMAP) analysis, we identified 12 cell types from musk glands, including two different acinar cells (clusters 0 and 10). In addition, the expression of core target genes and core transcription factors was verified by fluorescence in situ hybridization and immunohistochemistry. Combined with weighted gene co-expression network analysis (WGCNA), we obtained a deeper biological understanding of the relationship between core transcription factors, differentially expressed genes and musk secretion related pathways. This study lays a foundation for improving musk yield and meeting market demand. In the meantime, it also contributes to reducing the hunting and poaching of wild forest musk deer, protecting forest musk deer resources and maintaining ecological balance.
Project description:Bone morphogenic proteins (BMPs) function in virtually all tissues with cell-type specific outcomes. Since there are a relatively small number of BMP receptors this exquisite signaling specificity requires additional molecules to regulate the output of this pathway. We demonstrated that the receptor tyrosine kinase MuSK that is selectively expressed in muscle and plays a critical role in synapse formation and maintenance binds to BMP4 and related BMPs. Since BMPs regulate the transcription of a set of genes, we performed microarrays for wild-type and MuSK null muscle cells to test if MuSK regulates BMP responses in muscle cells. We shought to determine if MuSK regulates BMP responses in muscle cells and if the cell context made any difference in MuSK regulation of BMP pathway. To test this, expression profiles of untreated vs. BMP4-treated undifferentiated myoblast and differentiated myotube cultures were generated for both wild-type and MuSK-null genotypes. All conditions were done in triplicates. In total 24 arrays were analyzed.
Project description:Myofiber size regulation is critical in health, disease, and aging. MuSK (muscle-specific kinase) is a BMP (bone morphogenetic protein) co-receptor that promotes and shapes BMP signaling that is expressed at all neuromuscular junctions and is also present extrasynaptically in the slow soleus muscle. To investigate the role of the MuSK-BMP pathway in vivo we generated mice lacking the BMP-binding MuSK Ig3 domain. These ∆Ig3-MuSK mice are viable and fertile with innervation levels comparable to wild type. In 3-month-old mice myofibers are smaller in the slow soleus, but not in the fast TA. Here we use bulk RNA-seq to perform transcriptomic analysis of slow and fast mouse muscle. RNAseq analysis revealed soleus-selective decreases in RNA metabolism and protein synthesis pathways as well as dysregulation of IGF1 pathway components. Moreover, Akt-mTOR signaling is reduced in soleus but not TA. We propose that the MuSK-BMP pathway acts extrasynaptically to maintain myofiber size in slow muscle by promoting protein synthetic pathways including the IGF1-Akt-mTOR signaling. These results reveal a novel mechanism for regulating myofiber size in slow muscle and introduce the MuSK-BMP pathway as a target for promoting muscle growth and combatting atrophy.
Project description:Secreted proteins play critical roles in cellular communication. Methods enabling concurrent measurement of cellular protein secretion, phenotypes and transcriptomes are still unavailable. Here, we describe Time-Resolved Assessment of Protein Secretion from single cells by sequencing (TRAPS-seq). Released proteins are trapped onto cell surface and probed by oligonucleotide-barcoded antibodies before simultaneously sequenced with transcriptomes in single cells. TRAPS-seq unravels the phenotypic and transcriptional determinants of the secretion of pleiotropic Th1 cytokines (IFN-γ, IL-2 and TNF-α) in activated T cells. We further demonstrate the use of TRAPS-seq to track dynamic secretion of multiple cytokines over time, uncovering unique molecular signatures that govern the preservation or transition of single-cell cytokine secretions. Our results revealed that early central memory T cells with CD45RA expression (TCMRA) are important in both the production and maintenance of polyfunctional cytokines. TRAPS-seq presents a unique tool for seamless integration of secretomics measurement with multi-omics profiling in single cells.