The human neocortex exhibits characteristic regional patterning (arealization) critical for higher-order cognitive function. Disrupted arealization is implicated in neurodevelopmental disorders (NDDs), but current neocortical organoid models largely fail to recapitulate this patterning, limiting mechanistic understanding. We establish a straightforward method for generating arealized organoids through short-term early exposure to anterior or posterior morphogens. These treatments created distinct anteroposterior (AP) signaling centers, supporting long-lasting polarization validated by spatial and single-cell RNA sequencing, which revealed area-specific molecular signatures matching the prenatal human cortex. To demonstrate utility, we modeled fragile X syndrome (FXS) in organoids with distinct AP identities. FXS organoids showed disrupted expression gradients along the AP axis, consistent with alterations in autism spectrum disorder, demonstrating how regional patterning defects may contribute to NDD pathology. Together, our study provides a robust platform for generating neocortical organoids with AP molecular signatures and highlights the importance of modeling NDDs using experimental platforms with neuroanatomic specificity.

Radiopharmaceutical-based imaging and targeted radionuclide therapy are often limited by heterogeneous or absent molecular targets in tumors. Here, we present a stiffness-responsive mesenchymal stem cell (MSC)-assisted relayed tumor-targeting (SMART) platform that converts matrix stiffness into a programmable molecular entry point for radiotheranostics. Engineered MSCs sense elevated mechanical stiffness within the tumor microenvironment and induce localized expression of synthetic biomarkers, thereby enabling radiopharmaceutical targeting independent of endogenous target availability. As a proof of concept, SMART-driven expression of prostate-specific membrane antigen (PSMA) enables sensitive tumor detection by [68]Ga-PSMA-617 positron emission tomography (PET) and effective treatment with [177]Lu-AB-PSMA-617 across multiple tumor models, with improved sensitivity and reduced off-target uptake compared with conventional [18]F-fluorodeoxyglucose PET. This platform is readily adaptable to alternative synthetic targets and induced pluripotent stem cell (iPSC)-derived MSCs. By translating a universal physical feature of tumors into an actionable molecular signature, SMART expands the scope of precision radiotheranostics beyond native biomarkers.

Ovarian aging may contribute to systemic aging via the ovarian-systemic axis. This review outlines intrinsic ovarian cellular defects such as genomic instability, epigenetic shifts, and mitochondrial and proteostasis damage, which may trigger senescence-associated secretory phenotype (SASP)-related inflammaging, fibrosis, and distal pro-aging signals. Ovarian-derived endocrine disruption, especially estrogen decline, broadly affects bodily physiology. We summarize emerging multimodal interventions, including senolytics, metabolic reprogramming, regenerative medicine, and systemic approaches, and we discuss their dual potential to preserve fertility and intercept ovarian contributions to systemic aging. Ovarian aging is possibly associated with female age-related multimorbidity. Ovary-targeted prevention may extend healthspan, as assessed by combined reproductive and systemic clinical evaluations.

Therapeutic management of heart valve disease is currently hampered by a lack of mechanistic understanding of human valve development and pathobiology. Here, we develop a protocol to generate three-dimensional human heart valve-like tissues from pluripotent stem cells with enhanced maturational properties that partially recapitulate key molecular features of native valves. This includes an abundance of valve interstitial cells, resident macrophage cells, and the transcriptional profile of native heart valves. Importantly, we define a heart valve maturation signature from proteomic analysis and show that maturation of stem cell-derived valve cells is enhanced under 3D culture. We demonstrate that bioengineered valve-like microtissues can be used for modeling valve disease. Namely, treatment with inflammatory cytokines augmented tissue passive tension and induced molecular hallmarks of valve calcification, consistent with the pathological signature of clinical samples from diseased valves. Thus, bioengineered human heart valve-like tissues provide a platform to understand human heart valve development, maturation, and disease pathogenesis.

Heart valves maintain unidirectional blood flow, yet most understanding of their development and disease comes from animal models that do not fully capture human valve behavior. We present a human induced pluripotent stem cell (iPSC)-derived valve-like assembloid platform that models key aspects of in vivo valve features at the cellular and molecular levels. We found that mechanical forces, endothelial culture conditions, and fluidic shear stress respectively promote valve induction, maintenance, and extracellular matrix stratification. We further used this system to model human valve defects, including genetic mutations, injury, and hyperglycemia-related abnormalities. This assembloid platform enables the in vitro study of human valve development and disease mechanisms.

Programmable gene activation has broad therapeutic potential but remains constrained by the large effector size, limited multiplexing capacity, and challenges in in vivo delivery. Here, we develop the TIGR-TasR-mediated activator (TIGRa), a compact transcriptional activator derived from the tandem interspaced guide RNA (TIGR)-TIGR-associated protein (TasR) system that is mechanistically distinct from CRISPR-based activators. TIGRa is less than half the size of dSpCas9-based activators while achieving comparable or greater activation efficiency. Its native TIGR array architecture enables efficient multiplexed regulation, supporting simultaneous activation of up to 12 endogenous genes from a single compact construct. TIGRa-mediated multi-gene activation efficiently reprogrammed human fibroblasts into induced pluripotent stem cells. In addition, an all-in-one adeno-associated virus (AAV)-TIGRa vector activated endogenous CaMKII in vivo, promoting retinal ganglion cell survival and preserving visual function in a mouse model of N-methyl-D-aspartic (NMDA)-induced retinal injury. These results establish TIGRa as a compact and multiplexable platform for therapeutic gene regulation and in vivo genetic medicine.

Living therapeutic depots enable localized, adaptive therapy, but their success depends on persistence, activation, and therapeutic output. Harimoto et al.1 define mechanical requirements for durable bacterial containment, whereas Luo et al.2 integrate transient photosynthetic hydrogen production with cardiac therapy. Together, the studies demonstrate that therapeutic needs shape living therapeutic design.

Cellular development unfolds across both space and time, with lineage history influencing cellular identity and tissue organization. In this issue of Cell Stem Cell, Jia et al.[1] combine CRISPR lineage recording with spatial transcriptomics to reconstruct the clonal relationships and spatial organization of cells during mouse development and cancer progression.

The generation of highly plastic cell states in colorectal cancer that are prone to metastatic dissemination involves complex epigenetic reprogramming, rather than new genetic traits. Goto et al.[1] implement a serial orthotopic organoid transplantation framework to uncover the idea that losing Gata6, a guardian of the colonic lineage, promotes metastatic competence.

Modeling of cardiac pathologies in tissue-engineered models is coming of age. Two independent studies by Reid et al.[1] and Tani et al.[2] present in-depth multi-phenomics data from a human cardiac organoid (hCO) model and explore hCOs and engineered heart tissues (EHTs) for modeling of diastolic dysfunction.

Large-scale perturbation atlases have transformed systems biology, yet no equivalent resource exists for the human heart, where contractile function and transcriptomic state must be measured together. Here, we establish Cardiopedia-Ligand, a comprehensive perturbation-function-transcriptome atlas generated by stimulating human cardiac organoids (hCOs) with 87 ligands targeting 98 cell-membrane receptors expressed in the human heart. We developed an automated high-throughput pipeline enabling individualized contractility measurements and single-organoid mRNA sequencing. We use this pipeline to define both recognized and previously unrecognized functional and transcriptional clusters, including inotropes, endothelin peptides, extracellular matrix regulators, and multiple inflammatory clusters. Clustering analysis, machine learning, and the "fingerprinting" of human heart failure biopsies revealed previously underappreciated similarities between ligands and an interferon-γ signaling signature driving heart failure with preserved ejection fraction (HFpEF). Together, this comprehensive Cardiopedia-Ligand dataset provides a valuable and accessible resource for interrogating cardiac biology and human disease.

Myocardial ischemia-reperfusion (MIR) injury drives adverse remodeling and heart failure after ST-elevation myocardial infarction (STEMI), yet no therapy directly targets the fibrotic response. Here, we developed a good manufacturing practice-compatible extracellular vesicle (EV)-enriched secretome from bone marrow mesenchymal stromal cells and identified a laminin-521-based production strategy suitable for clinical translation. The EV-enriched secretome exhibited in vitro immunomodulatory activity, and in murine MIR-injury models, treatment preserved left ventricular ejection fraction, reduced platelet-derived growth factor receptor beta (PDGFRβ)-associated myofibroblast activation quantified by positron emission tomography (PET) imaging, attenuated fibrosis, and promoted reparative macrophage polarization. In a clinically relevant porcine ischemia-reperfusion model, intracoronary administration was cardioprotective. We further developed a clinically approved PDGFRβ-targeted PET-imaging platform for longitudinal assessment of fibrotic activity in STEMI patients, where preliminary observations suggest that myofibroblast activation persists for up to 2 months after STEMI in selected patients. Together, these findings establish a translational therapeutic-diagnostic framework for individualized management of MIR injury.

Fetal tissue transplantation established proof-of-concept for dopamine cell replacement in Parkinson's disease but yielded inconsistent outcomes due to limited tissue availability and cellular heterogeneity. Advances in generating high-purity dopamine progenitors from pluripotent stem cells have enabled standardized products that show safety and motor improvement in clinical trials. However, these trials revealed divergent outcomes arising at three levels: between clinical studies, driven by differences in cell products, baseline patient characteristics, or immunosuppressants; between patients, influenced by alloimmune factors, genetic background, or co-pathology; and within patients, where graft survival varies across transplantation sites due to the local microenvironment or surgical technique.

Using a xenogeneic reconstituted testis transplanted beneath the kidney capsule, Whelan et al. advance human and rhesus macaque pluripotent stem cell-derived germ cells beyond fetal prospermatogonia.1 Their study highlights developmental time, niche organization, and lineage history as central challenges for reconstructing faithful primate gametogenesis.