ZSWIM4 regulates embryonic patterning and BMP signaling by promoting nuclear Smad1 degradation.

The dorsoventral gradient of BMP signaling plays an essential role in embryonic patterning. Zinc Finger SWIM-Type Containing 4 (zswim4) is expressed in the Spemann-Mangold organizer at the onset of Xenopus gastrulation and is then enriched in the developing neuroectoderm at the mid-gastrula stages. Knockdown or knockout of zswim4 causes ventralization. Overexpression of zswim4 decreases, whereas knockdown of zswim4 increases the expression levels of ventrolateral mesoderm marker genes. Mechanistically, ZSWIM4 attenuates the BMP signal by reducing the protein stability of SMAD1 in the nucleus. Stable isotope labeling by amino acids in cell culture (SILAC) identifies Elongin B (ELOB) and Elongin C (ELOC) as the interaction partners of ZSWIM4. Accordingly, ZSWIM4 forms a complex with the Cul2-RING ubiquitin ligase and ELOB and ELOC, promoting the ubiquitination and degradation of SMAD1 in the nucleus. Our study identifies a novel mechanism that restricts BMP signaling in the nucleus.

The single-cell chromatin landscape in gonadal cell lineage specification.

Gonad development includes sex determination and divergent maturation of the testes and ovaries. Recent advances in measuring gene expression in single cells are providing new insights into this complex process. However, the underlying epigenetic regulatory mechanisms remain unclear. Here, we profiled chromatin accessibility in mouse gonadal cells of both sexes from embryonic day 11.5 to 14.5 using single-cell assay for transposase accessible chromatin by sequencing (scATAC-seq). Our results showed that individual cell types can be inferred by the chromatin landscape, and that cells can be temporally ordered along developmental trajectories. Integrative analysis of transcriptomic and chromatin-accessibility maps identified multiple putative regulatory elements proximal to key gonadal genes Nr5a1, Sox9 and Wt1. We also uncover cell type-specific regulatory factors underlying cell type specification. Overall, our results provide a better understanding of the epigenetic landscape associated with the progressive restriction of cell fates in the gonad.

WRN loss accelerates abnormal adipocyte metabolism in Werner syndrome.

BACKGROUND: Metabolic dysfunction is one of the main symptoms of Werner syndrome (WS); however, the underlying mechanisms remain unclear. Here, we report that loss of WRN accelerates adipogenesis at an early stage both in vitro (stem cells) and in vivo (zebrafish). Moreover, WRN depletion causes a transient upregulation of late-stage of adipocyte-specific genes at an early stage. METHODS: In an in vivo study, we generated wrn-/- mutant zebrafish and performed histological stain and Oil Red O staining to assess the fat metabolism. In an in vitro study, we used RNA-seq and ATAC-seq to profile the transcriptional features and chromatin accessibility in WRN depleted adipocytes. Moreover, we performed ChIP-seq to further study the regulatory mechanisms of metabolic dysfunction in WS. RESULTS: Our findings show that mechanistically WRN deficiency causes SMARCA5 upregulation. SMARCA5 is crucial in chromatin remodeling and gene regulation. Additionally, rescuing WRN could normalize SMARCA5 expression and adipocyte differentiation. Moreover, we find that nicotinamide riboside (NR) supplementation restores adipocyte metabolism in both stem cells and zebrafish models. CONCLUSIONS: Our findings unravel a new mechanism for the influence of WRN in the early stage of adipogenesis and provide a possible treatment for metabolic dysfunction in WS. These data provide promising insights into potential therapeutics for ageing and ageing-related diseases.

NAD+ dependent UPRmt activation underlies intestinal aging caused by mitochondrial DNA mutations.

Aging in mammals is accompanied by an imbalance of intestinal homeostasis and accumulation of mitochondrial DNA (mtDNA) mutations. However, little is known about how accumulated mtDNA mutations modulate intestinal homeostasis. We observe the accumulation of mtDNA mutations in the small intestine of aged male mice, suggesting an association with physiological intestinal aging. Using polymerase gamma (POLG) mutator mice and wild-type mice, we generate male mice with progressive mtDNA mutation burdens. Investigation utilizing organoid technology and in vivo intestinal stem cell labeling reveals decreased colony formation efficiency of intestinal crypts and LGR5-expressing intestinal stem cells in response to a threshold mtDNA mutation burden. Mechanistically, increased mtDNA mutation burden exacerbates the aging phenotype of the small intestine through ATF5 dependent mitochondrial unfolded protein response (UPRmt) activation. This aging phenotype is reversed by supplementation with the NAD+ precursor, NMN. Thus, we uncover a NAD+ dependent UPRmt triggered by mtDNA mutations that regulates the intestinal aging.

CWF19L2 is Essential for Male Fertility and Spermatogenesis by Regulating Alternative Splicing.

The progression of spermatogenesis along specific developmental trajectories depends on the coordinated regulation of pre-mRNA alternative splicing (AS) at the post-transcriptional level. However, the fundamental mechanism of AS in spermatogenesis remains to be investigated. Here, it is demonstrated that CWF19L2 plays a pivotal role in spermatogenesis and male fertility. In germline conditional Cwf19l2 knockout mice exhibiting male sterility, impaired spermatogenesis characterized by increased apoptosis and decreased differentiated spermatogonia and spermatocytes is observed. That CWF19L2 interacted with several spliceosome proteins to participate in the proper assembly and stability of the spliceosome is discovered. By integrating RNA-seq and LACE-seq data, it is further confirmed CWF19L2 directly bound and regulated the splicing of genes related to spermatogenesis (Znhit1, Btrc, and Fbxw7) and RNA splicing (Rbfox1, Celf1, and Rbm10). Additionally, CWF19L2 can indirectly amplify its effect on splicing regulation through modulating RBFOX1. Collectively, this research establishes that CWF19L2 orchestrates a splicing factor network to ensure accurate pre-mRNA splicing during the early steps of spermatogenesis.

ß-catenin mediates endodermal commitment of human ES cells via distinct transactivation functions.

BACKGROUND: ß-catenin, acting as the core effector of canonical Wnt signaling pathway, plays a pivotal role in controlling lineage commitment and the formation of definitive endoderm (DE) during early embryonic development. Despite extensive studies using various animal and cell models, the ß-catenin-centered regulatory mechanisms underlying DE formation remain incompletely understood, partly due to the rapid and complex cell fate transitions during early differentiation. RESULTS: In this study, we generated new CTNNB1-/- human ES cells (hESCs) using CRISPR-based insertional gene disruption approach and systematically rescued the DE defect in these cells by introducing various truncated or mutant forms of ß-catenin. Our analysis showed that a truncated ß-catenin lacking both N- and C-terminal domains (ΔN148C) could robustly rescue the DE formation, whereas hyperactive ß-catenin mutants with S33Y mutation or N-terminal deletion (ΔN90) had limited ability to induce DE lineage. Notably, the ΔN148C mutant exhibited significant nuclear translocation that was positively correlated with successful DE rescue. Transcriptomic analysis further uncovered that two weak ß-catenin mutants lacking the C-terminal transactivation domain (CTD) activated primitive streak (PS) genes, whereas the hyperactive ß-catenin mutants activated mesoderm genes. CONCLUSION: Our study uncovered an unconventional regulatory function of ß-catenin through weak transactivation, indicating that the levels of ß-catenin activity determine the lineage bifurcation from mesendoderm into endoderm and mesoderm.

A novel protein CYTB-187AA encoded by the mitochondrial gene CYTB modulates mammalian early development.

The mitochondrial genome transcribes 13 mRNAs coding for well-known proteins essential for oxidative phosphorylation. We demonstrate here that cytochrome b (CYTB), the only mitochondrial-DNA-encoded transcript among complex III, also encodes an unrecognized 187-amino-acid-long protein, CYTB-187AA, using the standard genetic code of cytosolic ribosomes rather than the mitochondrial genetic code. After validating the existence of this mtDNA-encoded protein arising from cytosolic translation (mPACT) using mass spectrometry and antibodies, we show that CYTB-187AA is mainly localized in the mitochondrial matrix and promotes the pluripotent state in primed-to-naive transition by interacting with solute carrier family 25 member 3 (SLC25A3) to modulate ATP production. We further generated a transgenic knockin mouse model of CYTB-187AA silencing and found that reduction of CYTB-187AA impairs females' fertility by decreasing the number of ovarian follicles. For the first time, we uncovered the novel mPACT pattern of a mitochondrial mRNA and demonstrated the physiological function of this 14th protein encoded by mtDNA.

Universal Health Coverage through Community Nursing Services: China vs. Hong Kong / Cobertura Universal de Saúde através dos serviços de enfermagem comunitários: China vs. Hong Kong / Cobertura Universal de Salud a través de Servicios Comunitarios de Enfermería: China versus Hong Kong

ABSTRACT Objective: this article looks at how the development of community nursing services in China and Hong Kong can enhance universal health coverage. Methods: literature and data review have been utilized in this study. Results: nursing services have evolved much since the beginning of the nursing profession. The development of community nursing services has expanded the scope of nursing services to those in need of, not just hospital-level nursing care, but more holistic care to improve health and quality of life. Conclusion: despite the one-country-two-systems governance and the difference in population and geography, Hong Kong and China both face the aging population and its complications. Community nursing services help to pave the road to Universal Health Coverage.

RESUMO Objetivo: este artigo analisa a forma como o desenvolvimento de serviços de enfermagem comunitários na China e Hong Kong pode melhorar a cobertura universal de saúde. Métodos: literatura e revisão de dados foram utilizados neste estudo. Resultados: serviços de enfermagem têm evoluído muito desde o início da profissão de enfermagem. O desenvolvimento dos serviços de enfermagem da comunidade ampliou o escopo dos serviços de enfermagem, para aqueles que precisam não apenas de cuidados de enfermagem de nível de hospital, mas cuidados mais holísticos para melhorar a saúde e qualidade de vida. Conclusão: apesar de ser “um-país-dois-sistemas” de governo, e as diferenças de população e geografia, Hong Kong e China enfrentam o envelhecimento da população e suas complicações. Os serviços de enfermagem da comunidade ajudam a pavimentar o caminho para a cobertura de saúde universal.

RESUMEN Objetivo: este artículo analiza cómo el desarrollo de los servicios de enfermería comunitaria en China y Hong Kong pueden expandir la cobertura universal de salud. Métodos: revisión de datos y literatura han sido utilizados en este estudio. Resultados: los servicios de enfermería han evolucionado mucho desde el comienzo de la profesión. El desarrollo de los servicios de enfermería comunitaria han ampliado el alcance de los servicios de enfermería a las personas que necesitan, no sólo en cuidados de enfermería en el hospital, sino también en una atención más integral para mejorar la salud y calidad de vida. Conclusión: a pesar del tipo de gobierno “un país, dos sistemas” y las diferencias de población y geografía, Hong Kong y China se enfrentan al envejecimiento de la población y sus complicaciones. Los servicios de enfermería comunitaria ayudan a allanar el camino hacia la cobertura universal de salud.