SETD4 in the Proliferation, Migration, Angiogenesis, Myogenic Differentiation and Genomic Methylation of Bone Marrow Mesenchymal Stem Cells

SETD4 inhibits prostate cancer development by promoting H3K27me3-mediated NUPR1 transcriptional repression and cell cycle arrest

The suppressor of variegation enhancer of zeste-trithorax (SET) domain methyltransferases have been reported to function as key regulators in multiple tumor types by catalyzing histone lysine methylation. Nevertheless, our understanding on the role of these lysine methyltransferases, including SETD4, in prostate cancer (PCa) remains limited. Hence, the specific role of SETD4 in PCa was investigated in this study. The expression of SETD4 in PCa cells and tissue samples was downregulated in PCa cells and tissue specimens, and decreased SETD4 expression led to inferior clinicopathological characteristics in patients with PCa. knockdown of SETD4 facilitated the proliferation of PCa cells and accelerated cell cycle progression. Mechanistically, SETD4 repressed NUPR1 transcription by methylating H3K27 to generate H3K27me3, subsequently inactivated Akt pathway and impeded the tumorigenesis of PCa. Our results highlight that SETD4 prevents the development of PCa by catalyzing the methylation of H3K27 and suppressing NUPR1 transcription, subsequently inactivating the Akt signaling pathway. The findings suggest the potential application of SETD4 in PCa prognosis and therapeutics.

Single-Cell and Spatial Transcriptomics Decodes Wharton's Jelly-Derived Mesenchymal Stem Cells Heterogeneity and a Subpopulation with Wound Repair Signatures

The highly heterogeneous characteristics of Wharton's jelly mesenchymal stem cells (WJ-MSCs) may be responsible for the poor clinical outcomes and poor reproducibility of treatments based on WJ-MSCs. Exploration of WJ-MSC heterogeneity with multimodal single-cell technologies will aid in establishing accurate MSC subtyping and developing screening protocols for dominant functional subpopulations. Here, the characteristics of WJ-MSCs are systematically analyzed by single cell and spatial transcriptome sequencing. Single-cell transcriptomics analysis identifies four WJ-MSC subpopulations, namely proliferative_MSCs, niche-supporting_MSCs, metabolism-related_MSCs and biofunctional-type_MSCs. Furthermore, the transcriptome, cellular heterogeneity, and cell-state trajectories of these subpopulations are characterized. Intriguingly, the biofunctional-type MSCs (marked by S100A9, CD29, and CD142) selected in this study exhibit promising wound repair properties in vitro and in vivo. Finally, by integrating omics data, it has been found that the S100A9⁺ CD29⁺ CD142⁺ subpopulation is more enriched in the fetal segment of the umbilical cord, suggesting that this subpopulation deriving from the fetal segment may have potential for developing into an ideal therapeutic agent for wound healing. Overall, the presented study comprehensively maps the heterogeneity of WJ-MSCs and provides an essential resource for future development of WJ-MSC-based drugs.

SETD4 cells contribute to brain development and maintain adult stem cell reservoir for neurogenesis

Cellular quiescence facilitates maintenance of neural stem cells (NSCs) and their subsequent regenerative functions in response to brain injury and aging. However, the specification and maintenance of NSCs in quiescence from embryo to adulthood remain largely unclear. Here, using Set domain-containing protein 4 (SETD4), an epigenetic determinant of cellular quiescence, we mark a small but long-lived NSC population in deep quiescence in the subventricular zone of adult murine brain. Genetic lineage tracing shows that SETD4⁺ cells appear before neuroectoderm formation and contribute to brain development. In the adult, conditional knockout of Setd4 resulted in quiescence exit of NSCs, generating newborn neurons in the olfactory bulb and contributing to damage repair. However, long period deletion of SETD4 lead to exhaustion of NSC reservoir or SETD4 overexpression caused quiescence entry of NSCs, leading to suppressed neurogenesis. This study reveals the existence of long-lived deep quiescent NSCs and their neurogenetic capacities beyond activation.

Unmasking the mammalian SET domain-containing protein 4

SET domain-containing protein 4 (SETD4) is a member of a unique class of protein lysine methyltransferases. Here, we introduce the basic features of SETD4 and summarize the key findings from recent studies with emphases on its roles in tissue development and tumorigenesis, and its methylation substrates. SETD4 is expressed in stem/progenitor cells. Ablation of Setd4⁺ cells impedes the repopulation of acinar cells after pancreatic injury. Setd4 deletion in mice promotes the recovery of radiation-induced bone marrow (BM) failure by boosting the function of BM niche, facilitates the generation of endothelial cells and neovascularization of capillary vessels in the heart, enhances the proliferation of BM mesenchymal stem cells and disrupts the TLR4 signaling in BM-derived macrophages. SETD4 expression is also associated with the maintenance of quiescent breast cancer stem cells. While mouse Setd4 knockout delays radiation-induced T-lymphoma formation, elevated SETD4 expression has been observed in some proliferative cancer cells and is associated with a pro-survival potential. Oncogenic fusions of SETD4 have also been identified in cancer, albeit rare. In addition, SETD4 methylates lysine-570 in the C-terminal globular domain of KU70, which enables KU70 translocation to cytoplasm to suppress apoptosis.

Myogenic Determination and Differentiation of Chicken Bone Marrow-Derived Mesenchymal Stem Cells under Different Inductive Agents

Simple Summary

Muscle development is an important performance factor of broilers. This is the first investigation to evaluate the myogenic differentiation effect of chicken bone marrow-derived mesenchymal stem cells (BM-MSCs) induced by 5-azacytidine (5-Aza). qRT-PCR was performed to compare myogenic determination and differentiation of chicken BM-MSCs under different inductive agents. Transcriptome sequencing and a Western blot were performed to further confirm the myogenic effect induced by 5-Aza. In conclusion, our study indicated that BM-MSCs demonstrate better myogenic differentiation potential under 5-day treatment with 5-Aza. Our findings lay the foundation for constructing a myogenic determination and differentiation model of chicken BM-MSCs.

Abstract

Poultry plays an important role in the meat consumer market and is significant to further understanding the potential mechanism of muscle development in the broiler. Bone marrow-derived mesenchymal stem cells (BM-MSCs) can provide critical insight into muscle development due to their multi-lineage differentiation potential. To our knowledge, chicken BM-MSCs demonstrate limited myogenic differentiation potential under the treatment with dexamethasone (DXMS) and hydrocortisone (HC). 5-azacytidine (5-Aza), a DNA demethylating agent, which has been widely used in the myogenic differentiation of BM-MSCs in other species. There is no previous report that applies 5-Aza to myogenic-induced differentiation of chicken BM-MSCs. In this study, we evaluated the myogenic determination and differentiation effect of BM-MSCs under different inductive agents. BM-MSCs showed better differentiation potential under the 5-Aza-treatment. Transcriptome sequence analysis identified 2402 differentially expressed DEGs including 28 muscle-related genes after 5-Aza-treatment. The DEGs were significantly enriched in Gene Ontology database terms, including in the cell plasma membrane, molecular binding, and cell cycle and differentiation. KEGG pathway analysis revealed that DEGs were enriched in myogenic differentiation-associated pathways containing the PI3K-Akt signaling pathway, the TGF-β signaling pathway, Arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy, and hypertrophic cardiomyopathy, which suggested that BM-MSCs differentiated into a muscle-like phenotype under 5-Aza-treatment. Although BM-MSCs have not formed myotubes in our study, it is worthy of further study. In summary, our study lays the foundation for constructing a myogenic determination and differentiation model in chicken BM-MSCs.

SETD4-mediated KU70 methylation suppresses apoptosis

The mammalian KU70 is a pleiotropic protein functioning in DNA repair and cytoplasmic suppression of apoptosis. We report a regulatory mechanism by which KU70’s cytoplasmic function is enabled due to a methylation at K570 of KU70 by SET-domain-containing protein 4 (SETD4). While SETD4 silencing reduces the level of methylated KU70, over-expression of SETD4 enhances methylation of KU70. Mutations of Y272 and Y284 of SETD4 abrogate methylation of KU70. Although SETD4 is predominantly a nuclear protein, the methylated KU70 is enriched in the cytoplasm. SETD4 knockdown enhances staurosporine (STS)-induced apoptosis and cell killing. Over-expression of the wild-type (WT) SETD4, but not the SETD4-Y272/Y284F mutant, suppresses STS-induced apoptosis. The KU70-K570R (mouse Ku70-K568R) mutation dampens the anti-apoptosis activity of KU70. Our study identifies KU70 as a non-histone substrate of SETD4, discovers a post-translational modification of KU70, and uncovers a role for SETD4 and KU70-K570 methylation in the suppression of apoptosis.

Wang et al. identify the methylation of mammalian KU70 by SETD4. This post-translational modification is critical for KU70 localization to the cytoplasm and subsequent suppression of apoptosis.

Methyltransferase SET domain family and its relationship with cardiovascular development and diseases

Abnormal epigenetic modification is closely related to the occurrence and development of cardiovascular diseases. The SET domain (SETD) family is an important epigenetic modifying enzyme containing SETD. They mainly affect gene expression by methylating H3K4, H3K9, H3K36 and H4K20. Additionally, the SETD family catalyzes the methylation of non-histone proteins, thereby affects the signal transduction of signal transduction and activator of transcription (STAT) 1, Wnt/β-catenin, hypoxia-inducible factor (HIF)-1α and Hippo/YAP pathways. The SETD family has the following regulatory effects on cardiovascular development and diseases: regulating coronary artery formation and cardiac development; protecting cardiac tissue from ischemia reperfusion injury; regulating inflammation, oxidative stress and apoptosis in cardiovascular complications of diabetes; participating in the formation of pulmonary hypertension; regulating thrombosis, cardiac hypertrophy and arrhythmia. This article summarizes the basic structures, expression regulation mechanisms and the role of existing SETD family members in cardiovascular development and diseases, in order to provide a basis for understanding the molecular mechanism of cardiovascular disease and exploring the therapeutic targets.