The differentiation of mesodermal cells (MCs) in the early stage of embryonic development contributes to the organogenesis of several core organs. However, the single-cell molecular architecture of MCs and the key molecular events during the differentiation remain unclear. We performed single-cell RNA sequencing (RNA sequencing) and single-cell assay for transposase-accessible chromatin (ATAC-Seq) to analyze the developmental features of MCs to heart, kidney, spleen, liver, and brain in human embryos at gestational ages 7-17 weeks. We found that EGR1 might be relevant to the differentiation of heterogeneous MC sub-clusters. Meanwhile, RPL10P9+PTMAP5+ MCs had the closest expression profiling with endocardial cells. NDUFA4L2+A2M+ MCs presented the potentials to form endothelial cells (ECs) and hematopoietic stem cells, and MEF2C might be involved in this process. These findings provide insights into the molecular architecture and lineage progression of MCs during early human embryonic organogenesis, offering a valuable reference for regenerative medicine and organ bioengineering.

ObjectivesWe fabricated a pre-vascularized bioprinted hydrogel construct via coculture of human umbilical vein endothelial cells (HUVECs) and dental pulp stem cells (DPSCs) to investigate the role of ephrinB2 in 3D capillary-like cord self-assemble.Materials and methodsAfter bioprinting gelatin methacrylate (GelMA) hydrogels, we performed a morphology observation of the inside capillary-like cords, quantitative analysis of branch points and cord length, and examination of pericyte markers in DPSCs. Next, we assessed the influence of DPSCs: HUVECs ratio and degree of functionalization (DoF) of GelMA on the cord formation. To investigate the role of ephrinB2, we used either EphB4/ephrinB2 inhibitor peptide, or knocked down or upregulated ephrinB2 in DPSCs, and evaluated their effects on these cords’ generation. Finally, bioprinted hydrogels were subcutaneously transplanted into mice to assess in vitro vascularization.ResultsAbundant capillary-like cords containing lumen were found in bioprinted hydrogels. DPSCs wrapped outside the cords and expressed pericyte markers. A 1:3 DPSCs: HUVECs ratio and a 30% DoF of GelMA led to significant increase in branch points and cord length by over 2-fold and 3-fold, respectively. Adding EphB4/ephrinB2 inhibitor peptide or knockdown of ephrinB2 in DPSCs impaired capillary-like cord generation, whereas overexpression of ephrinB2 in DPSCs promoted cord formation. In in vivo experiments, a significant over 3-fold increase in vessel number was observed in hydrogels when ephrinB2 was upregulated in DPSCs compared with wild-type DPSCs.ConclusionsOverexpression of ephrinB2 in DPSCs promoted in vitro capillary-like cord formation and in vivo vascularization in a 3D bioprinted hydrogel.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12860-025-00558-4.

BackgroundMethyltransferase-like 16 (METTL16) is involved in regulating kidney disease progression. This study aimed to investigate the effect of METTL16 on the progression of diabetic kidney disease (DKD) and its potential mechanism.MethodsSV40-MES13 cells were transfected with METTL16 siRNA (siMETTL16), scramble control (siNC), or RAP1B siRNA (siRAP1B) under low glucose (LG) or high glucose (HG) conditions. Subsequently, RNA immunoprecipitation (RIP) assays, cell viability assays, EdU staining, TUNEL staining, ROS staining, and MDA detection were carried out.ResultsIn SV40-MES13 cells, cell viability, the number of EdU-positive cells, the MDA level, METTL16 mRNA, and protein levels were greater in the HG groups than in the control group. Moreover, cell viability, the number of EdU-positive cells, and VIMENTIN protein levels were lower, whereas the apoptosis rate and ROS and MDA levels were greater in the HG + siMETTL16 group than in the HG + siNC group. RAP1B mRNA and protein levels and N6-methyladenosine modification levels were greater in the HG group than in the control group but lower in the HG + siMETTL16 group than in the HG + siNC group. Furthermore, the METTL16 protein bound to the RAP1B mRNA. Compared with those in the HG + siNC group, cell viability, the number of EdU-positive cells, and VIMENTIN protein levels were decreased, whereas the ROS and MDA levels were increased in the HG + siRAP1B group.ConclusionMETTL16 knockdown attenuates cell viability and fibrosis by reducing m6A modification and the expression of RAP1B in high glucose–treated mesangial cells, suggesting the potential of METTL16 as a treatment target for DKD.Supplementary InformationThe online version contains supplementary material available at 10.1186/s12860-025-00559-3.