Cell reports最新文献

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a dense stroma, low immunogenicity, and resistance to therapy. Cancer-associated fibroblasts (CAFs) are key stromal cells within the tumor microenvironment (TME) that drive tumor progression. Interleukin-1 (IL-1) promotes fibrosis, pathogenic inflammation, and poor prognosis in PDAC. Using a single-cell multi-omic approach, we investigate the IL-1 signaling axis in human and mouse models of PDAC, identifying nuclear factor of activated T cells (NFAT) transcription factors as key mediators. IL1R1⁺ CAFs activate an inflammatory phenotype associated with elevated NFAT motif activity and gene expression. In vivo, NFAT inhibition in a mouse model of PDAC significantly reduces tumor weight and fibrosis, supporting its pro-tumorigenic role. Our findings suggest that NFAT mediates IL-1-induced inflammation in PDAC, highlighting its potential as a therapeutic target. This study demonstrates the power of multi-omic analyses to uncover therapeutic targets within the complex TME.

Prenatal glucocorticoid exposure is associated with higher risks of autism spectrum disorder (ASD), yet the underlying mechanisms remain poorly understood. Here, we report that late-pregnancy exposure to dexamethasone (a synthetic glucocorticoid) induces social memory deficiency and increased repetitive behaviors in offspring with an imbalance of neurotransmission in the hippocampus. Single-cell RNA sequencing uncovers an expansion of MRC1⁺ microglia, with arrested maturation. Strikingly, this population exhibits selective F13a1 (encoding a coagulation factor functioning as transglutaminase) upregulation. Early postnatal inhibition of F13A1 restores microglial maturation and ameliorates behavioral abnormalities. An elevated level of F13A1 is also observed in the plasma of postnatal rats and human umbilical cord blood exposed to prenatal glucocorticoids. Together, it suggests that prenatal glucocorticoid exposure disrupts the maturation of MRC1⁺ microglia, thereby causing social memory impairment and increased repetitive behaviors. This underscores that arrested maturation within a cluster of microglia may be related to ASD and identifies F13A1 as a promising therapeutic target and biomarker.

Nucleoside diphosphate kinase (Ndk) is a ubiquitous enzyme that maintains the cellular nucleoside triphosphate (NTP) pool and participates in many other pathways of eukaryotes and prokaryotes. Here, we show that in Escherichia coli, Ndk is regulated by dephosphorylation of its phosphohistidine intermediate via the phosphatase SixA, thereby inhibiting nucleotide phosphoryl transfer activity. We further show that loss of this regulation alters the metabolic state of E. coli in low-nutrient conditions and reduces survival in long-term stationary phase. Similar regulation of Ndk by a phosphohistidine phosphatase has been reported previously for human cells, although the molecular interactions differ. The prevalence of SixA and Ndk orthologs in prokaryotes and the appearance of this regulatory mechanism in both E. coli and humans suggest that phosphohistidine phosphatase-mediated control of nucleoside diphosphate kinases may be widespread.

Disruption of the blood-brain barrier (BBB) increases vascular permeability and promotes neuroinflammation, contributing to Alzheimer's disease (AD) progression. However, the molecular drivers of BBB dysfunction and neuroinflammation in AD remain poorly defined. Here, we identify angiopoietin-2 (ANGPT2) as a central mediator of BBB breakdown and AD progression. Transcriptomic analyses of human AD brains revealed elevated ANGPT2 expression in endothelial cells correlating with disease severity. In 5xFAD mice, endothelial-specific Angpt2 deletion reduced β-amyloid deposition, while Angpt2 overexpression via an adeno-associated viral vector exacerbated the plaque burden. Mechanistically, ANGPT2 suppression of TIE2 signaling increased vascular leakage and fibrin deposition, triggering microglial activation and neuroinflammatory responses that accelerated disease progression. Single-nucleus transcriptomic analyses further revealed Angpt2-driven microglial dysfunction and neuronal impairment consistent with memory deficits observed in behavioral assays. These findings establish ANGPT2 as a critical driver of BBB dysfunction and neuroinflammation in AD and highlight its therapeutic potential.

Applying cryoelectron microscopy (cryo-EM) to small protein complexes is usually challenging due to their lack of features for particle alignment. Here, we characterized antibody responses to 21 kDa human immunodeficiency virus (HIV) membrane-proximal external region germline-targeting (MPER-GT) immunogens through cryo-EM by complexing them with 10E8 or Fabs derived from MPER-GT-immunized animals. Distinct antibody-antigen interactions were analyzed using atomic models generated from cryo-EM maps. Mutagenesis screening revealed that off-target monoclonal antibodies (mAbs), which do not compete with 10E8, bind non-MPER epitopes, and the binding of two most dominant epitopes were verified by cryo-EM. The structures of 10E8-class on-target Fabs showed binding patterns that resemble the YxFW motif in the 10E8 heavy chain complementarity-determining region 3 (HCDR3) loop. Additionally, we demonstrate that high-resolution maps can be generated from heterogeneous samples with pooled competing Fabs. Overall, our findings will facilitate the optimization of MPER-GT antigens and push the size limit for cryo-EM-based epitope mapping with smaller antigens and heterogeneous antibody mixes.

Despite recent advances in cell migration mechanics, the principles governing rapid T cell movement remain unclear. Efficient migration is critical for antitumoral T cells to locate and eliminate cancer cells. To investigate the upper limits of cell speed, we develop a hybrid stochastic-mean field model of bleb-based cell motility. Our model suggests that cell-matrix adhesion-free bleb migration is highly inefficient, challenging the feasibility of adhesion-independent migration as a primary fast mode. Instead, we show that T cells can achieve rapid migration by combining bleb formation with adhesion-based forces. Supporting our predictions, three-dimensional gel experiments confirm that T cells migrate significantly faster under adherent conditions than in adhesion-free environments. These findings highlight the mechanical constraints of T cell motility and suggest that controlled modulation of tissue adhesion could enhance immune cell infiltration into tumors. Our work provides insights into optimizing T cell-based immunotherapies and underscores that indiscriminate antifibrotic treatments may hinder infiltration.

We optogenetically mapped the function and spatial organization of inhibitory circuits formed by interneurons (INs) within the claustrum, a highly interconnected but poorly understood brain region. INs expressing parvalbumin or somatostatin attenuate claustrum output by inhibiting projection neurons (PNs), while INs expressing vasoactive intestinal peptide promote claustrum output by disinhibiting PNs. The spatial organization and degree of convergence differ for each interneuronal circuit. A computational model incorporating measured circuit properties predicts that differential inhibition of PNs by INs toggles claustrum output between cortical and subcortical brain regions and that the spatial organization of IN circuits nonlinearly filters claustrum output according to the strength and spatial distribution of excitatory input. Experimental measurements show that the claustrum spatially filters cortical input as predicted by the model. We conclude that the organization of its inhibitory circuits allows the claustrum to serve as a filter that improves the signal-to-noise ratio of signals transmitted to its downstream targets.

Age-related macular degeneration (AMD) is a leading cause of vision loss worldwide. Genome-wide association studies (GWASs) of AMD have identified dozens of risk loci that may house disease targets. However, variants at these loci are largely noncoding, making it difficult to assess their function and whether they are causal. Here, we present a single-cell gene expression and chromatin accessibility atlas of human retinal pigment epithelium (RPE) and choroid to systematically analyze both coding and noncoding variants implicated in AMD. We employ HiChIP and activity-by-contact modeling to map enhancers in these tissues and predict cell and gene targets of risk variants. We further perform allele-specific self-transcribing active regulatory region sequencing (STARR-seq) to functionally test variant activity in RPE cells, including in the context of complement activation. Our work nominates pathogenic variants and mechanisms in AMD and offers a rich and accessible resource for studying diseases of the RPE and choroid.

PDX1 is a key transcription factor regulating insulin expression in response to glucose. Our previous work showed that PDX1 is also stimulated by amino acids (aa). Here, we demonstrate that PDX1 broadly mediates aa-regulated transcriptional programs in β cells, especially those controlling β cell proliferation and function. Mechanistically, mTORC1 phosphorylates PDX1 at serine 61 (S61), enhancing its protein stability and transcriptional activity. A certain monogenic diabetes mutation disrupts this phosphorylation and impairs PDX1 function. To investigate its physiological role, we generated mice carrying S61A and S61E mutations, mimicking unphosphorylated and phosphorylated states. S61 phosphorylation promoted insulin expression and β cell proliferation, leading to Western diet-induced hyperinsulinemia, obesity, and hepatic steatosis. These findings reveal the central role of aa-mTORC1-PDX1 signaling in coordinating β cell proliferation and function under both physiological and pathological conditions.

PIWI-interacting RNAs (piRNAs) guide PIWI endoribonucleases to destroy transposon transcripts, ensuring animal fertility. Here, we report the cryo-electron microscopy structure of the MIWI-pachytene piRNA complex isolated from mouse testes. The piRNA is held via non-specific charge-based interactions with the RNA backbone and by specific recognition of the first nucleotide uridine by residues within the MID and PIWI domains. The first six nucleotides of the guide RNA take up the A-form conformation to facilitate pairing with the target. The RNA channel is wider than that observed in insect PIWI proteins, explaining the tolerance for piRNA seed:target mismatches. The PIWI endonuclease domain is in an inactive "un-plugged" state, with the loop containing a catalytic residue (E671) requiring structural re-orientation for activity. Furthermore, the PIWI domain reveals a conserved pre-formed pocket that may serve to accommodate a conserved tryptophan from the interacting factor GTSF1 to promote small RNA-guided endoribonuclease activity.