The process of a single-celled zygote developing into a complex multicellular organism is precisely regulated at spatial and temporal levels in vivo. However, understanding the mechanisms underlying development, particularly in humans, has been constrained by technical and ethical limitations associated with studying natural embryos. Harnessing the intrinsic ability of embryonic stem cells (ESCs) to self-organize when induced and assembled, researchers have established several embryo models as alternative approaches to studying early development in vitro. Recent studies have revealed the critical role of extraembryonic cells in early development; and many groups have created more sophisticated and precise ESC-derived embryo models by incorporating extraembryonic stem cell lines, such as trophoblast stem cells (TSCs), extraembryonic mesoderm cells (EXMCs), extraembryonic endoderm cells (XENs, in rodents), and hypoblast stem cells (in primates). Here, we summarize the characteristics of existing mouse and human embryonic and extraembryonic stem cells and review recent advancements in developing mouse and human embryo models.

The murine mammary gland is sustained by distinct pools of stem cells that are limited in space and time, exhibiting both unipotency and bipotency. However, the specific identities of the bipotent and unipotent mammary stem cells remain unclear. In this study, we investigated spatial heterogeneity of the mammary gland at the single-cell transcriptional level. We found that mammary basal cells exhibited spatially distinct populations and characteristics, which can be further divided based on the expression of CD34 and CD200 markers. Notably, CD34−CD200+ basal cells enriched at the nipple region demonstrated strong long-term self-renewal ability and possessed the highest stem cell frequency, while CD34+CD200− basal cells enriched in the terminal end buds (TEBs) showed reduced stem cell potency. Through lineage tracing experiments based on their signature genes, we discovered that Bcl11b+ cells were enriched in the CD34−CD200+ population and exhibited bipotency even in the postnatal mammary gland, with an increasing contribution to mammary epithelia observed during long-term tracing and after multiple rounds of pregnancies. Conversely, lineage tracing of Sema3a+ cells, enriched in the CD34+CD200− population, predominantly revealed their unipotent nature and significant contribution during alveologenesis. Notably, the Bcl11b+ cells displayed a slow response to pregnancy but contributed to long-term mammary homeostasis, in contrast to the rapid response observed in Sema3a+ cells. In addition, Bcl11b progenies survived much better than Sema3a progenies during involution stage, thereby exhibiting increased coverage in the mammary gland after multiple rounds of pregnancies. Importantly, depletion of Bcl11b in Krt14+ mammary basal cells resulted in reduced bipotency of mammary stem cells and impaired their long-term contribution to the mammary gland. Overall, our study identifies distinct bipotent and unipotent populations of mammary basal cells with different dynamic properties that play critical roles in maintaining postnatal mammary homeostasis. These findings are crucial for advancing our understanding of breast health and breast cancer research.

Recipients’ age has emerged as a key factor that impacts on acute renal allograft rejection and graft survival. Age-related functional and structural changes in the immune system have been observed, yet the precise influence of aged immunity on kidney transplant remains unclear. In an initial retrospective analysis of clinical data gathered from two major centers in China and Germany, we found a correlation between aging and mitigated rejection outcomes in kidney recipients. To study the mechanism, we performed kidney transplantation on mice and observed attenuated allograft rejection in senescent recipients. Single-cell transcriptome analysis of allograft kidneys indicated a protective role of p21high macrophages in aged mice. Supernatant collected from p21high macrophage primary culture inhibited the cytotoxic function and proliferation of CD8+ T cells. Zfp36 is highly expressed in senescent p21high macrophages. To determine its role in renal allograft rejection, we studied mice with Zfp36 conditionally deleted in macrophages (Zfp36-cKO). These mice developed exacerbated allograft rejection with enhanced IL-27 production and CD8+ T cell hyperactivation. Inhibition of IL-27 with neutralizing antibody or deletion of IL-27 receptor on CD8+ T cells reversed acute renal allograft rejection in Zfp36-cKO mice. Moreover, in vitro silencing Zfp36 with siRNA led to impaired degradation of IL-27 p28 mRNA and a subsequent increase of IL-27 in p21high macrophages. In conclusion, senescent macrophages protect renal allograft rejection by suppressing CD8+ T cells via a Zfp36/IL-27-dependent mechanism. These findings may provide innovative therapeutic strategies for addressing kidney allograft rejection.

The α7 nicotinic acetylcholine receptor (nAChR), a pentameric ligand-gated ion channel, plays important roles in cognition, neuroprotection, and anti-inflammation. As a potential drug target, α7 nAChR has different binding sites for different ligands, particularly agonists and positive allosteric modulators (PAMs). Ago-PAMs can both directly activate and allosterically modulate α7 nAChR. However, the mechanism underlying α7 nAChR modulation by ago-PAM has yet to be fully elucidated. Here, we present cryo-EM structures of α7 nAChR in complex with the ago-PAM GAT107 and Ca2+ in the open and desensitized states, respectively. Our results from both structural comparisons and functional assays suggest an allosteric mechanism underlying GAT107 modulation and calcium potentiation of α7 nAChR, involving local conformational changes in the ECD–TMD coupling region and a global structural rearrangement in the transmembrane domain. This work provides a new mechanism of α7 nAChR gating distinct from that of conventional agonist binding. These findings would aid in drug design and enrich our biophysical understanding of pentameric ligand-gated ion channels.

Coxsackievirus B3 (CVB3)-induced acute heart failure (AHF) is a common cause of cardiogenic death in young- and middle-aged people. However, the key molecular events linking CVB3 to AHF remain largely unknown, resulting in a lack of targeted therapy strategies thus far. Here, we unexpectedly found that Viperin deficiency does not promote CVB3 infection but protects mice from CVB3-induced AHF. Importantly, cardiac-specific expression of Viperin can induce cardiac dysfunction. Mechanistically, CVB3-encoded 3C protease rescues Viperin protein expression in cardiomyocytes by lowering UBE4A. Viperin in turn interacts with and reduces STAT1 to activate SGK1-KCNQ1 signaling, and eventually leads to cardiac electrical dysfunction and subsequent AHF. Furthermore, we designed an interfering peptide VS-IP1, which blocked Viperin-mediated STAT1 degradation and therefore prevented CVB3-induced AHF. This study established the first signaling link between CVB3 and cardiac electrical dysfunction, and revealed the potential of interfering peptides targeting Viperin for the treatment of CVB3-induced AHF.

Natural Medicinal Materials (NMMs) have a long history of global clinical applications and a wealth of records and knowledge. Although NMMs are a major source for drug discovery and clinical application, the utilization and sharing of NMM knowledge face crucial challenges, including the standardized description of critical information, efficient curation and acquisition, and language barriers. To address these, we developed ShennongAlpha, an artificial intelligence (AI)-driven sharing and collaboration platform for intelligent knowledge curation, acquisition, and translation. For standardized knowledge curation, the platform introduced a Systematic Nomenclature to enable accurate differentiation and identification of NMMs. More than fourteen thousand Chinese NMMs have been curated into the platform along with their knowledge. Furthermore, the platform pioneered chat-based knowledge acquisition, standardized machine translation, and collaborative knowledge updating. Together, our study represents the first major advance in leveraging AI to empower NMM knowledge sharing, which not only marks a novel application of AI for science, but also will significantly benefit the global biomedical, pharmaceutical, physician, and patient communities.

Gout, a common and painful disease, stems from hyperuricemia, where elevated blood urate levels lead to urate crystal formation in joints and kidneys. The human urate transporter 1 (hURAT1) plays a critical role in urate homeostasis by facilitating urate reabsorption in the renal proximal tubule, making it a key target for gout therapy. Pharmacological inhibition of hURAT1 with drugs such as dotinurad, benzbromarone, lesinurad, and verinurad promotes urate excretion and alleviates gout symptoms. Here, we present cryo-electron microscopy structures of native hURAT1 bound with these anti-gout drugs in the inward-open state, and with urate in inward-open, outward-open, and occluded states. Complemented by mutagenesis and cell-based assays, these structures reveal the mechanisms of urate reabsorption and hURAT1 inhibition. Our findings elucidate the molecular basis of urate transport and anti-gout medication action and provide a structural framework for the rational design of next-generation therapies for hyperuricemia and gout.

An outbreak of mpox has triggered concerns regarding the adequacy of intervention strategies. Passive immunity conferred by neutralizing antibodies exhibits potential in the prophylaxis and treatment of orthopoxvirus infections. Despite this, the investigations of effective antibody therapeutics have been hindered by the varied nature of orthopoxvirus envelope proteins and the intricate mechanisms underpinning viral invasion. Our study involves the production of six mpox virus (MPXV) envelope proteins, which are relatively conservative and considered to play a role in the neutralization process. We employed a synthetic nanobody (Nb) library to derive a broad array of specific Nbs against these viral proteins. We identified a cross-reactive Nb, termed M1R-01, which targets the M1R protein and effectively neutralizes both vaccinia virus (VACV) and MPXV. Notably, the M1R-01-based antibody strategy provided optimal protection against a lethal VACV challenge in mice. Additionally, we determined the crystal structure of the M1R–Nb complex, uncovering novel binding attributes of M1R-01 and detailed conformational epitope information. This work provides a promising candidate for the therapy and prophylaxis of orthopoxvirus infections.