Isolation and characterization of liver epithelial progenitor cells from normal adult rhesus monkeys （Macaca mulatta）

Dear Editor, Based on their ability to proliferate and the capacity to differentiate into specific cell types, hepatic progenitor/stem cells （HPCs） from adult human liver may have potential therapeutic effects on end-stage liver failure. In addition, adult HPCs have a reduced risk of teratoma for- mation and are not subject to the same ethical issues as fetal HPCs or embryonic stem cells . The HPCs from rhesus monkeys are relevant because they may serve as a valuable preclinical model for assessment of cell therapy in humans. To date, there are no reports of HPCs or liver epithelial progenitor cells （LEPCs） isolated from normal adult rhesus monkey although a few studies in other species were reported. We report here for the first time the successful isolation of rhesus monkey LEPCs （mLEPCs） from normal adult livers （n = 12）.

Epigenetic regulators as the foundation for molecular classification of colorectal cancer

Colorectal cancer (CRC) accounts for approximately 10% of newly diagnosed cancer cases and cancer-related deaths worldwide~1. The identification of molecular subtypes of CRCs has significantly advanced treatment strategies,including targeted therapy and immunotherapy.

Characterization of kinesin-like proteins in silkworm posterior silkgland cells

Kinesins are microtubule-based motors involved in various intracellular transports. Neurons, flagellated cells, and pigment cells have been traditionally used as model systems to study the cellular functions of kinesins. Here, we report silkworm posterior silkgland （PSG）, specialized cells with an extensive endomembrane system for intracellular transport and efficient secretion of fibroin, as a novel model for kinesin study. To investigate kinesindriven intracellular transport in PSG cells, we cloned five silkworm kinesin-like proteins （KLPs）, BmKinesin-1, BmKinesin-6, BmKinesin-7, BmKinesin-13, and BmKinesin-14A. We determined their expression patterns by relative real-time PCR and western blotting. Immunofluorescence microscopy verified their colocalization with microtubules. By combining pull-down assays, LC-MS/MS, and western blotting analysis, we identified many potential cargoes of BmKinesin-1 in PSG, including fibroin-containing granules and exuperantia-associated ribonucleoprotein （RNP） complexes. Moreover, BmKinesin-13 overexpression disrupted the microtubule network in BmN cells, which is consistent with a role of Kinesin-13 in regulating microtubule dynamics in other organisms. On the basis of these results, we concluded that PSG might have advantages in elucidating mechanisms of intracellular transport in secretory tissues and could serve as a potential model for kinesin studies.

Efficient generation of hepatocyte-like cells from human induced pluripotent stem cells

Human induced pluripotent stem （iPS） cells are similar to embryonic stem （ES） cells, and can proliferate intensively and differentiate into a variety of cell types. However, the hepatic differentiation of human iPS cells has not yet been reported. In this report, human iPS cells were induced to differentiate into hepatic cells by a stepwise protocol. The expression of liver cell markers and liver-related functions of the human iPS cell-derived cells were monitored and compared with that of differentiated human ES cells and primary human hepatocytes. Approximately 60% of the differentiated human iPS cells at day 7 expressed hepatic markers alpha fetoprotein and Alb. The differentiated cells at day 21 exhibited liver cell functions including albumin Asecretion, glycogen synthesis, urea production and inducible cytochrome P450 activity. The expression of hepatic markers and fiver-related functions of the iPS cellderived hepatic ceils were comparable to that of the human ES cell-derived hepatic cells. These results show that human iPS cells, which are similar to human ES cells, can be efficiently induced to differentiate into hepatocyte-like cells.

Pericentrin contains five NESs and an NLS essential for its nucleocytoplasmic trafficking during the cell cycle

Pericentrin, a conserved centrosomal component, provides the structural scaffold to anchor numerous centrosomal proteins, and thus plays an essential role in the organization and function of the centrosome and the mitotic spindle. Although pericentrin was shown to localize in the cytoplasm and reported to be sensitive to leptomycin B （LMB）, a specific inhibitor of Crml, the regions within pericentrin that serve as signals for transporting in and out of the nucleus have not yet been identified. In this study, we identified five novel nuclear export signals （NESs） in pericentrin with diverse export activities. All of the five NESs could bind to Crml in a LMB-sensitive way when mediating the nuclear export of pericentrin. We also demonstrated that the region of amino acids 8-42 in pericentrin contains a tripartite nuclear localization signal （NLS） consisting of three clusters of basic amino acids. The NLS of pericentrin binds to importin β directly or via the adaptor importin α to form the import complex, which could be disrupted by RanQ69L, a dominant-negative Ran GTPase possessing high affinity for importin β. Furthermore, we found that mutation of the NESs in full-length pericentrin results in both nuclear and cytoplasmic localization, and mutation of the NLS abolishes the nuclear import of pericentrin. On the basis of these results, we suggest that the NESs and NLS of pericentrin are essential for its subcellular localization and nucleocytoplasmic trafficking during the cell cycle.

Corrigendum to“Long-term correction of hemophilia B through CRISPR/Cas9 induced homology-independent targeted integration”[Journal of Genetics and Genomics(2022)49,1114-1126]

The authors regret that the grant number“21CJ1402200”in the Acknowledgments session should be replaced as“21JC1402200”.The corrected contents areprovided as follows.

Characterization of mesenchymal stem cells in human fetal bone marrow by single-cell transcriptomic and functional analysis

Bone marrow mesenchymal stromal/stem cells (MSCs) are a heterogeneous population that can self-renew and generate stroma,cartilage, fat, and bone. Although a significant progress has been made toward recognizing about the phenotypic characteristics ofMSCs, the true identity and properties of MSCs in bone marrow remain unclear. Here, we report the expression landscape of humanfetal BM nucleated cells (BMNCs) based on the single-cell transcriptomic analysis. Unexpectedly, while the common cell surfacemarkers such as CD146, CD271, and PDGFRa used for isolating MSCs were not detected, LIFR+PDGFRB+ were identified to bespecific markers of MSCs as the early progenitors. In vivo transplantation demonstrated that LIFR+PDGFRB+CD45-CD31-CD235a-MSCs could form bone tissues and reconstitute the hematopoietic microenvironment (HME) effectively in vivo. Interestingly, wealso identified a subpopulation of bone unipotent progenitor expressing TM4SF1+CD44+CD73+CD45-CD31-CD235a-, which hadosteogenic potentials, but could not reconstitute HME. MSCs expressed a set of different transcription factors at the different stagesof human fetal bone marrow, indicating that the stemness properties of MSCs might change during development. Moreover,transcriptional characteristics of cultured MSCs were significantly changed compared with freshly isolated primary MSCs. Ourcellular profiling provides a general landscape of heterogeneity, development, hierarchy, microenvironment of the human fetal BMderivedstem cells at single-cell resolution.

The chemical reprogramming of unipotent adult germ cells towards authentic pluripotency and de novo establishment of imprinting

Although somatic cells can be reprogrammed to pluripotent stem cells(PsCs)with pure chemicals,authentic pluripotency of chemically induced pluripotent stem celis(CipsCs)has never been achieved through tetraploid complementation assay.Spontaneous reprogramming of spermatogonial stem cells(ssCs)was another non-transgenic way to obtain PsCs,but this process lacks mechanistic explanation.Here,we reconstructed the trajectory of mouse SsC reprogramming and developed a five-chemical combination,boosting the reprogramming effciency by nearly 80-to 100-folds.More importantly,chemical induced germline-derived PsCs(5C-gPSCs),but not gpsCs and chemical induced pluripotent stem cells,had authentic pluripotency,as determined by tetraploid complementation.Mechanistically,ssCs traversed through an inverted pathway of in vivo germ ceil development,exhibiting the expression signatures and DNA methylation dynamics from spermatogonia to primordial germ cells and further to epiblasts.Besides,ssC-specific imprinting control regions switched from biallelic methylated states to monoallelic methylated states by imprinting demethylation and then re-methylation on one of the two alleles in 5c-gPsCs,which was apparently distinct with the imprinting reprogramming in vivo as DNA methylation simultaneously occurred on both alleles.Our work sheds ight on the unique regulatory network underpinning SsC reprogramming,providing insights to understand generic mechanisms for cell-fate decision and epigenetic-relateddisorders in regenerative medicine.

Pancreas-specific Pten deficiency causes partial resistance to diabetes and elevated hepatic AKT signaling

PTEN, a negative regulator of the phosphatidylinositol-3-kinase/AKT pathway, is an important modulator of insulin signaling. To determine the metabolic function of pancreatic Pten, we generated pancreas-specific Pten knockout （PPKO） mice. PPKO mice had enlarged pancreas and elevated proliferation of acinar cells. They also exhibited hypoglycemia, hypoinsulinemia, and altered amino metabolism. Notably, PPKO mice showed delayed onset of streptozotocin （STZ）-induced diabetes and sex-biased resistance to high-fat-diet （HFD）-induced diabetes. To investigate the mechanism for the resistance to HFD-induced hyperglycemia in PPKO mice, we evaluated AKT phosphorylation in major insulin-responsive tissues： the liver, muscle, and fat. We found that Pten loss in the pancreas causes the elevation of AKT signaling in the liver. The phosphorylation of AKT and its downstream substrate GSK3β was increased in the liver of PPKO mice, while PTEN level was decreased without detectable excision of Pten allele in the liver of PPKO mice. Proteomics analysis revealed dramatically decreased level of 78-kDa glucose-regulated protein （GRP78） in the liver of PPKO mice, which may also contribute to the lower blood glucose level of PPKO mice fed with HFD. Together, our findings reveal a novel response in the liver to pancreatic defect in metabolic regulation, adding a new dimension to understanding diabetes resistance.

Cyclin B1 is localized to unattached kinetochores and contributes to efficient microtubule attachment and proper chromosome alignment during mitosis

Cyclin B1 is a key regulatory protein controlling cell cycle progression in vertebrates. Cyclin B1 binds CDK1, a cy-clin-dependent kinase catalytic subunit, forming a complex that orchestrates mitosis through phosphorylation of key proteins. Cyclin B1 regulates both the activation of CDK1 and its subcellular localization, which may be critical for substrate selection. Here, we demonstrate that cyclin B1 is concentrated on the outer plate of the kinetochore during prometaphase. This localization requires the cyclin box region of the protein. Cyclin B1 is displaced from individual kinetochores to the spindle poles by microtubule attachment to the kinetochores, and this displacement is dependent on the dynein/dynactin complex. Depletion of cyclin B1 by vector-based siRNA causes inefficient attachment between kinetochores and microtubules, and chromosome alignment defects, and delays the onset of anaphase. We conclude that cyclin B1 accumulates at kinetochores during prometaphase, where it contributes to the correct attachment of mi- crotubules to kinetochores and efficient alignment of the chromosomes, most likely through localized phosphorylation of specific substrates by cyclin B1-CDK1. Cyclin B1 is then transported from each kinetochore as microtubule attachment is completed, and this relocalization may redirect the activity of cyclin B1-CDK1 and contribute to inactivation of the spindle assembly checkpoint.

Gfi1.1 regulates hematopoietic lineage differentiation during zebrafish embryogenesis

Growth factor independence 1 （GFI1） is important for maturation of mammalian lymphocytes and neutrophils and maintenance of adult hematopoietic stem cells （HSCs）. The role of GFI1 in embryonic hematopoiesis is less well characterized. Through an enhancer trap screen and bioinformatics analysis, we identified a zebrafish homolog of Gill （named grill） and analyzed its function during embryonic development. Expression of both an endogenous griLl gene and a GFP reporter gene inserted near its genomic locus was detected in hematopoietic cells of zebrafish embryos. Morpholino （MO） knockdown of gill.1 reduced expression of scl, Imo2, c-myb, mpo, ragl, gatal and hemoglobin alpha embryonic-1 （hbael）, as well as the total amount of embryonic hemoglobin, but increased expression ofpu.1 and l-plastin. Under the same conditions, MO injection did not affect the markers involved in vascular and pronephric development. Conversely, overexpression of gill.1 via mRNA injection enhanced expression ofgatal but inhibited expression ofpu.1. These findings suggest that Gill.1 plays a critical role in regulating the balance of embryonic erythroid and myeloid lineage determination, and is also required for the differentiation of lymphocytes and granulocytes during zebrafish embryogenesis.

Drug repurposing screening and mechanism analysis based on human colorectal cancer organoids

Colorectal cancer(CRC)is a highly heterogeneous cancer and exploring novel therapeutic options is a pressing issue that needs to be addressed.Here,we established human CRC tumor-derived organoids that well represent both morphological and molecular heterogeneities of original tumors.To efficiently identify repurposed drugs for CRC,we developed a robust organoid-based drug screening system.By combining the repurposed drug library and computation-based drug prediction,335 drugs were tested and 34 drugs with anti-CRC effects were identified.More importantly,we conducted a detailed transcriptome analysis of drug responses and divided the drug response signatures into five representative patterns:differentiation induction,growth inhibition,metabolism inhibition,immune response promotion,and cell cycle inhibition.The anticancer activities of drug candidates were further validated in the established patient-derived organoids-based xenograft(PDOX)system in vivo.We found that fedratinib,trametinib,and bortezomib exhibited effective anticancer effects.Furthermore,the concordance and discordance of drug response signatures between organoids in vitro and pairwise PDOX in vivo were evaluated.Our study offers an innovative approach for drug discovery,and the representative transcriptome features of drug responses provide valuable resources for developing novel clinical treatments for CRC.

Improved clinical outcomes of rhG-CSF-mobilized blood and marrow haploidentical transplantation compared to propensity score-matched rhG-CSF-primed peripheral blood stem cell haploidentical transplantation:a multicenter study

The effects of haploidentical rhG-CSF-mobilized blood and marrow transplantation(HBMT) on hematological malignances are well established. Previous prospective single-center studies have demonstrated better survival after HBMT versus haploidentical rhG-CSF-mobilized peripheral blood stem cell transplantation(HPBSCT) for acute leukemia(AL) not in remission(NR) or in more than the second complete remission(>CR2). To test the hypothesis that HBMT is still superior to HPBSCT for patients with AL, multiple myeloma(MM), or non-Hodgkin lymphoma(NHL) in CR1/CR2 and for patients with chronic myeloid leukemia in the first and second chronic phase lacking a matched donor, we designed a propensity score method-based multicenter study.Hematopoietic recovery, acute graft-versus-host disease(aGVHD), and chronic GVHD were comparable between the HBMT group(n=168) and the HPBSCT group(n=42). No significant differences were found in non-relapse mortality rate(20.17%±3.58%and 27.24%±7.16%, P=0.18) or relapse rate(19.96%±3.72% and 28.49%±8.25%, P=0.32) between the HBMT group and the HPBSCT group. HBMT recipients had better overall survival(65.0%±4.2% and 54.2%±8.3%, P=0.037) and disease-free survival(59.9%±4.6% and 44.3%±8.7%, P=0.051). Multivariate analysis showed that HPBSCT was associated with poorer DFS(HR(95%CI), 1.639(0.995–2.699), P=0.052). Our comparisons showed that HBMT was superior to HPBSCT as a post-remission treatment for patients lacking an identical donor.

Spatially resolved expression landscape and generegulatory network of human gastric corpus epithelium

Molecular knowledge of human gastric corpus epithelium remains incomplete.Here,by integrated analyses using single-cell RNA sequencing(scRNA-seq),spatial transcriptomics,and single-cell assay for transposase accessible chromatin sequencing(scATAC-seq)techniques,we uncovered the spatially resolved expression landscape and gene-regulatory network of human gastric corpus epithelium.Specifically,we identified a stem/progenitor cell population in the isthmus of human gastric corpus,where EGF and WNT signaling pathways were activated.Meanwhile,LGR4,but not LGR5,was responsible for the activation of WNT signaling pathway.Importantly,FABP5 and NME1 were identified and validated as crucial for both normal gastric stem/progenitor cells and gastric cancer cells.Finally,we explored the epigenetic regulation of critical genes for gastric corpus epithelium at chromatin state level,and identified several important cell-type-specific transcription factors.In summary,our work provides novel insights to systematically understand the cellular diversity and homeostasis of human gastric corpus epithelium in vivo.

Human 8-cell embryos enable efficient induction of disease-preventive mutations without off-target effect by cytosine base editor

Approximately 140 million people worldwide are homozygous carriers of APOE4(ε4),a strong genetic risk factor for late onset familial and sporadic Alzheimer’s disease(AD),91%of whom will develop AD at earlier age than heterozygous carriers and noncarriers.Susceptibility to AD could be reduced by targeted editing of APOE4,but a technical basis for controlling the off-target effects of base editors is necessary to develop low-risk personalized gene therapies.Here,we first screened eight cytosine base editor variants at four injection stages(from 1-to 8-cell stage),and found that FNLS-YE1 variant in 8-cell embryos achieved the comparable base conversion rate(up to 100%)with the lowest bystander effects.In particular,80%of AD-susceptibleε4 allele copies were converted to the AD-neutralε3 allele in humanε4-carrying embryos.Stringent control measures combined with targeted deep sequencing,whole genome sequencing,and RNA sequencing showed no DNA or RNA off-target events in FNLS-YE1-treated human embryos or their derived stem cells.Furthermore,base editing with FNLS-YE1 showed no effects on embryo development to the blastocyst stage.Finally,we also demonstrated FNLS-YE1 could introduce known protective variants in human embryos to potentially reduce human susceptivity to systemic lupus erythematosus and familial hypercholesterolemia.Our study therefore suggests that base editing with FNLS-YE1 can efficiently and safely introduce known preventive variants in 8-cell human embryos,a potential approach for reducing human susceptibility to AD or other genetic diseases.

Single-cell analyses identify distinct and intermediate states of zebrafish pancreatic islet development

Pancreatic endocrine islets are vital for glucose homeostasis. However, the islet developmental trajectory and its regulatory network are not well understood. To define the features of these specification and differentiation processes, we isolated individual islet cells from TgBAC(neurod1:EGFP) transgenic zebrafish and analyzed islet developmental dynamics across four different embryonic stages using a single-cell RNA-seq strategy. We identified proliferative endocrine progenitors, which could be further categorized by different cell cycle phases with the G1/S subpopulation displaying a distinct differentiation potential. We identified endocrine precursors, a heterogeneous intermediate-state population consisting of lineage-primed alpha, beta and delta cells that were characterized by the expression of lineage-specific transcription factors and relatively low expression of terminally differentiation markers. The terminally differentiated alpha, beta, and delta cells displayed stage-dependent differentiation states, which were related to their functional maturation. Our data unveiled distinct states, events and molecular features during the islet developmental transition, and provided resources to comprehensively understand the lineage hierarchy of islet development at the single-cell level.

TIP60 acetylation of Bub1 regulates centromeric H2AT120 phosphorylation for faithful chromosome segregation

Proper function of the centromeres ensures correct attachment of kinetochores to spindle microtubules and faithful chromosome segregation in mitosis.Defects in the integrity and function of centromeres can result in chromosome missegregation and genomic instability.Bub1 is essential for the mitotic centromere dynamics,yet the underlying molecular mechanisms remain largely unclear.Here,we demonstrate that TIP60 acetylates Bub1 at K424 and K431 on kinetochores in early mitosis.This acetylation increases the kinase activity of Bub1 to phosphorylate centromeric histone H2A at T120(H2Ap T120),which recruits Aurora B and Shugoshin 1(Sgo1)to regulate centromere integrity,protect centromeric cohesion,and ensure the subsequent faithful chromosome segregation.Expression of the nonacetylated Bub1 mutant reduces its kinase activity,decreases the level of H2Ap T120,and disrupts the recruitment of centromere proteins and chromosome congression,leading to genomic instability of daughter cells.When cells exit mitosis,HDAC1-regulated deacetylation of Bub1 decreases H2Ap T120 levels and thereby promotes the departure of centromeric CPC and Sgo1,ensuring timely centromeres disassembly.Collectively,our results reveal a molecular mechanism by which the acetylation and deacetylation cycle of Bub1 modulates the phosphorylation of H2A at T120 for recruitment of Aurora B and Sgo1 to the centromeres,ensuring faithful chromosome segregation during mitosis.

An effective pharmacological hydrogel induces optic nerve repair and improves visual function

Irreversible eye lesions, such as glaucoma and traumatic optic neuropathy, can cause blindness;however, no effective treatments exist. The optic nerve, in particular, lacks the capacity to spontaneously regenerate, requiring the development of an effective approach for optic nerve repair, which has proven challenging. Here, we demonstrate that a combination of the small molecules 3BDO and trichostatin A(TSA)—which regulate mTOR and HDAC, respectively—packaged in thermosensitive hydrogel for 4-week-sustained release after intravitreal injection, effectively induced optic nerve regeneration in a mouse model of optic nerve crush injury. Moreover, this combination of 3BDO and TSA also protected axon projections and improved visual responses in an old mouse model(11 months old) of glaucoma. Taken together, our data provide a new, local small molecule-based treatment for the effective induction of optic nerve repair, which may represent a foundation for the development of pharmacological methods to treat irreversible eye diseases.

Efficient and Specific Modifications of the Drosophila Genome by Means of an Easy TALEN Strategy

Technology development has always been one of the forces driving breakthroughs in biomedical research. Since the time of Thomas Morgan, Drosophilists have, step by step, developed powerful genetic tools for manipulating and functionally dissecting the Drosophila genome, but room for improving these technologies and developing new techniques is still large, especially today as biologists start to study systematically the functional genomics of different model organisms, including humans, in a high-throughput manner. Here, we report, for the first time in Drosophila, a rapid, easy, and highly specific method for modifying the Drosophila genome at a very high efficiency by means of an improved transcription activator-like effector nuclease （TALEN） strategy. We took advantage of the very recently developed ＂unit assembly＂ strategy to assemble two pairs of specific TALENs designed to modify the yellow gene （on the sex chromosome） and a novel autosomal gene. The mRNAs of TALENs were subsequently injected into Drosophila embryos. From 31.2% of the injected Fo fertile flies, we detected inheritable modification involving the yellow gene. The entire process from construction of specific TALENs to detection of inheritable modifications can be accomplished within one month. The potential applications of this TALEN-mediated genome modification method in Drosophila are discussed.

AtFH8 Is Involved in Root Development under Effect of Low-Dose Latrunculin B in Dividing Cells

Formins have been paid much attention for their potent nucleating activity. However, the connection between the in vivo functions of AtFHs （Arabidopsis thaliana formin homologs） and their effects on actin organization is poorly understood, in this study, we characterized the bundling activity of AtFH8 in vitro and in vivo. Biochemical analysis showed that AtFH8（FH1FH2） could form dimers and bundle preformed actin filaments or induce stellar structures during actin polymerization. Expression of truncated forms of AtFH8 and immunolocalization analysis showed that AtFH8 localized primarily to nuclear envelope in interphase and to the new cell wall after cytokinesis, depending primarily on its N-terminal transmembrane domain. GUS histochemical staining showed AtFH8 was predominantly expressed in Arabidopsis root meristem, vasculature, and outgrowth points of lateral roots. The primary root growth and lateral root initiation of atfh8 could be decreased by latrunculin B （LatB）. Analysis of the number of dividing cells in Arabidopsis root tips showed that much fewer dividing cells in Lat B-treated atfh8 plants than wild-type plants, which indicates that AtFH8 was involved in cell division. Actin cytoskeleton in root meristem of atfh8-1 was more sensitive to LatB treatment than that of wild-type. Altogether, our results indicate that AtFH8 is an actin filament nucleator and bundler that functions in cell division and root development.