Modeling hepatoblastoma development with human fetal liver organoids reveals YAP1 activation is sufficient for tumorigenesis

Dear Editor,Hepatoblastoma(HB)is a predominant hepatic neoplasm that develops in children from 0 to 4 years of age at the rate of 2.16 per 1,000,000.It originates from abnormal differentiation of hepatocyte precursors(hepatoblasts)during embryogenesis(Sumazin et al.,2017).Approximately 20%of children with HB have metastasis in lung at diagnosis,which indicates poor prognosis(Angelico et al.,2019).While surgery in combination of chemotherapy and/or metastasectomy is the most popular therapy,relapse happens in a significant portion of HB patients(Zhang et al.,2021).Therefore,novel and less aggressive therapies targeting the pathogenesis of HB should be explored to prolong patients’s disease-free survival as well as to improve their quality of life.

dBrms1 Acts as a Positive Regulator of Notch Signaling in Drosophila Wing

The highly conserved Notch signaling is precisely regulated at different steps in a series of developmental events. However, little is known about the regulation of Notch receptor at transcriptional level. Here, we demonstrate that dBrms1 is involved in regulating Notch signaling in Drosophila wing. We show that knockdown of dBrms1 by RNA interference(RNAi) in wing disc suppresses the expression of Notch signaling target genes wingless(wg), cut and Enhancer of split m8 [E(spl)m8]. Consistently, the levels of Wg and Cut are reduced in the dBrms1 mutant clones. Importantly, loss of dBrms1 leads to significant reduction of Notch proteins. Furthermore, depletion of dBrms1 results in apparent downregulation of Notch transcription in the wing disc. Moreover, we find that dBrms1 is functionally conserved with human Breast cancer metastasis suppressor 1 like(hBRMS1L) in the modulation of Notch signaling. Taken together, our data provide important insights into the biological function of dBrms1 in regulating Notch signaling.

Drosophila heparan sulfate 3-0 sulfotransferase B Null Mutant Is Viable and Exhibits No Defects in Notch Signaling

Heparan sulfate proteoglycans(HSPGs) are critically involved in a variety of biological events.The functions of HSPGs are determined by the nature of the core proteins and modifications of heparan sulfate(HS) glycosaminoglycan(GAG) chains.The distinct O-sulfotransferases are important for nonrandom modifications at specific positions.Two HS 3-0 sulfotransferase(Hs3st) genes,Hs3st-A and Hs3st-B,were identified in Drosophila.Previous experiments using RNA interference(RNAi) suggested that Hs3st-B was required for Notch signaling.Here,we generated a null mutant of Hs3st-B via ends-out gene targeting and examined its role(s) in development.We found that homozygous Hs3st-B mutants have no neurogenic defects or alterations in the expression of Notch signaling target gene.Thus,our results strongly argue against an essential role for Hs3st-B in Notch signaling.Moreover,we have generated two independent Hs3st-A RNAi lines which worked to deplete Hs3st-A.Importantly,Hs3st-A RNAi combined with Hs3st-B mutant flies did not alter the expression of Notch signaling components,arguing that both Hs3st-A and Hs3st-B were not essential for Notch signaling.The establishment of Hs3st-B mutant and effective Hs3st-A RNAi lines provides essential tools for further studies of the physiological roles of Hs3st-A and Hs3st-B in development and homeostasis.

Ihog proteins contribute to integrin-mediated focal adhesions

Integrin expression forms focal adhesions, but how this process is physiologically regulated is unclear. Ihog proteins are evolutionarily conserved, playing roles in Hedgehog signaling and serving as trans-homophilic adhesion molecules to mediate cell-cell interactions. Whether these proteins are also engaged in other cell adhesion processes remains unknown. Here, we report that Drosophila Ihog proteins function in the integrin-mediated adhesions. Removal of Ihog proteins causes blister and spheroidal muscle in wings and embryos, respectively. We demonstrate that Ihog proteins interact with integrin via the extracellular portion and that their removal perturbs integrin distribution. Finally, we show that Boc, a mammalian Ihog protein,rescues the embryonic defects caused by removing its Drosophila homologs. We thus propose that Ihog proteins contribute to integrin-mediated focal adhesions.

中国老年患者万古霉素群体药动学及个体化给药应用研究

本研究旨在构建中国老年患者万古霉素群体药动学(population pharmacokinetics, PPK)模型,为中国老年患者提供个体化给药方案。前瞻性收集使用万古霉素的中国老年患者数据,采用酶联免疫分析法检测万古霉素稳态血药浓度,记录患者性别、年龄、体重、合并用药、感染类型以及实验室检查指标等信息。NONMEM(nonlinearmixed-effectsmodel)软件构建PPK模型,蒙特卡洛模拟法设计老年患者的万古霉素初始给药剂量表。研究发现开颅术后脑膜炎与肾小球滤过率是影响万古霉素清除率的主要协变量;并设计了万古霉素在老年开颅术后脑膜炎及非开颅术后脑膜炎患者中的初始给药剂量推荐表。本研究最终建立了能估算中国老年患者万古霉素个体清除率的PPK模型,为老年患者万古霉素的个体化给药提供参考。

Generation of liver bipotential organoids with a small-molecule cocktail

Understanding the mechanism of how cholangiocytes(liver ductal cells)are activated upon liver injury and specified to hepatocytes would permit liver regenerative medicine.Here we achieved long-term in vitro expansion of mouse liver organoids by modulating signaling pathways with a combination of three small-molecule compounds.CHIR-99021,blebbistatin,and forskolin together maintained the liver organoids in bipotential stage with both cholangiocyte-and hepatocyte-specific gene expression profiles and enhanced capacity for further hepatocyte differentiation.By employing a chemical approach,we demonstrated that Wnt/β-catenin,NMII-Rac,and PKA-ERK are core signaling pathways essential and sufficient for mouse liver progenitor expansion.Moreover,the advanced small-molecule culture of bipotential organoids facilitates the ex vivo investigation of liver cell fate determination and the application of organoids in liver regenerative medicine.

The Sterile 20-Like Kinase Tao Controls Tissue Homeostasis by Regulating the Hippo Pathway in Drosophila Adult Midgut

The proliferation and differentiation of adult stem cells must be tightly controlled in order to maintain resident tissue homeostasis.Dysfunction of stem cells is implicated in many human diseases, including cancer. However, the regulation of stem cell proliferation and differentiation is not fully understood. Here we show that the sterile-like 20 kinase, Tao, controls tissue homeostasis by regulating the Hippo pathway in the Drosophila adult midgut. Depletion of Tao in the progenitors leads to rapid intestinal stem cell(ISC) proliferation and midgut homeostasis loss. Meanwhile, we find that the Janus kinase(JAK)/signal transducer and activator of transcription(STAT)signaling activity and cytokine production are significantly increased, resulting in stimulated ISC proliferation. Furthermore, expression of the Hippo pathway downstream targets, Diap1 and bantam, is dramatically increased in Tao knockdown intestines. Consistently, we show that the Yorkie(Yki) acts downstream of Tao to regulate ISC proliferation. Together, our results provide insights into our understanding of the mechanisms of stem cell proliferation and tissue homeostasis control.

Defense of COVID-19 by Human Organoids

Coronavirus disease 2019(COVID-19),caused by severe acute respiratory syndrome coronavirus-2(SARS-CoV-2),has created an immense menace to public health worldwide,exerting huge effects on global economic and political conditions.Understanding the biology and pathogenesis mechanisms of this novel virus,in large parts,relies on optimal physiological models that allow replication and propagation of SARS-CoV-2.Human organoids,derived from stem cells,are three-dimen-sional cell cultures that recapitulate the cellular organization,transcriptional and epigenetic signatures of their counterpart organs.Recent studies have indicated their great values as experimental virology platforms,making human organoid an ideal tool for investigating host-pathogen interactions.Here,we summarize research developments for SARS-CoV-2 infection of various human organoids involved in multiple systems,including lung,liver,brain,intestine,kidney and blood vessel organoids.These studies help us reveal the pathogenesis mechanism of COVID-19,and facilitate the development of effec-tive vaccines and drugs as well as other therapeutic regimes.