搜索结果：The American journal of pathology

The field of pathology has experienced several transformative changes in recent years with the advent of digital pathology and spatial multi-omics. These technologies have enhanced every aspect of pathology practice, from streamlining daily workflows to generating high-fidelity multi-omics data that provide pathologists with novel tools to refine disease profiling and clinical diagnosis. Each layer of multimodal data (genomic, metabolomic, proteomic, or transcriptomic) has uncovered a distinct facet of disease pathologies, and combined with machine learning/artificial intelligence-based data analysis and pattern recognition models, has provided holistic understanding of regulatory mechanisms underpinning them. However, high-dimensional data have far exceeded the volume, scale, and complexity of immunostaining methods implemented by pathologists and, thus, have generated significant challenges related to deconvolution, interpretation, and clinical translation. Furthermore, these multimodal studies have predominantly relied on computational methods to process data and extract disease-relevant insights, thus raising questions around relevance or role of a pathologist in this new era of multi-omics. This review will provide a perspective on the evolving fields of molecular histopathology and spatial -omics, leveraging them to approach disease profiling, and redefining the role of a pathologist during this process.

Epithelial barrier dysfunction is a hallmark of inflammatory bowel diseases; however, the mechanisms underlying such impairment remain incompletely understood. In the present study, a dextran sulfate sodium-induced colitis model was used to investigate how the inflammatory environment damages the intestinal mucosa. The results demonstrated that colitogenic ambiance enhances intestinal epithelial cell death, delays epithelial cell proliferation, and exacerbates mucosal erosion. Unexpectedly, this work identified a previously unrecognized role for Notch signaling in mediating these effects. Specifically, the colitogenic milieu reduces Notch/mechanistic target of rapamycin complex 1 (mTORC1)-mediated intestinal epithelial cell proliferation to promote goblet cell differentiation. Chemical activation of Notch signaling stimulated intestinal epithelial cell proliferation and reduced goblet cell differentiation in the colitic mucosa, further aggravating mucosal damage. Conversely, inhibition of Notch or mTORC1 signaling during mucosal repair reduced intestinal epithelial cell proliferation and enhanced goblet cell differentiation, corroborating the implication of Notch and mTORC1 signaling in both processes. Collectively, these findings uncover a context-dependent role for the Notch-mechanistic target of rapamycin axis in regulating intestinal epithelial cell proliferation and differentiation in the colitic mucosa and suggest that its targeted modulation may hold therapeutic potential in inflammatory bowel diseases.

Metastasis is a major threat in breast cancer, often involving lymph node (LN) dissemination. However, the cellular composition and signaling networks within the metastatic microenvironment remain incompletely characterized, resulting in limited understanding of the molecular mechanisms driving LN metastasis. In this study, a comprehensive single-cell atlas of metastatic niches was constructed using single-cell RNA-sequencing data from 78 primary breast tumors and their paired LN metastatic samples. Among the epithelial cell subpopulations, distinct clusters representing early-disseminated cancer cells were identified. Notably, profound metabolic reprogramming and immune modulation was observed during the malignant transformation of epithelial cells, which may contribute to the invasive and metastatic phenotype of early-disseminated cancer cells. Furthermore, the communication network within the metastatic microenvironment has also been delineated systematically, where crosstalk among lymphocyte, macrophage, and epithelial cells drove immunosuppressive features of LN metastasis. To explore potential therapeutic interventions, computational drug repositioning was conducted and four tyrosine kinase receptor inhibitors were identified that may target key interactions within this crosstalk. These results were validated using spatial transcriptomics data of four metastatic LN tissue sections from an integrated single-cell RNA-sequencing cohort. Collectively, this study discussed the cellular architecture and regulatory interplay underlying LN metastasis in breast cancer, offering novel insights that may inform targeted therapeutic strategies for patients with metastatic disease.

Psoriasis is a chronic, immune-mediated dermatologic disorder characterized by the hyperproliferation of keratinocytes and dysregulated immune signaling. Although genome-wide association studies have identified susceptibility loci, the multifactorial nature of the disease underlines the importance of nongenetic regulatory mechanisms. Among these epigenetic modifications are those that critically link genetic predisposition with environmental stimuli. This review offers an in-depth overview of the current insights into the role of epigenetic regulation in the pathophysiology of psoriasis. Key mechanisms, including aberrant DNA methylation, histone post-translational modifications (eg, H3K27ac, H3K4me3), and dysregulated noncoding RNAs, are discussed in the context of inflammatory signaling and immune cell function. This review also explores how environmental factors such as UV radiation and air pollution induce the epigenetic reprogramming that perpetuates the proinflammatory state. Furthermore, it highlights the translational potential of targeting epigenetic regulators and epigenome-editing technologies, including clustered regularly interspaced short palindromic repeats (CRISPR) fusion systems, as precision therapeutic strategies. In parallel, advances in single-cell epigenomics, spatial transcriptomics, and the profiling of circulating biomarkers offer novel diagnostic tools. Despite advances, challenges persist, including the limited predictive value of preclinical models and variable epigenetic profiles. Positioning epigenetics as the bridge between genetic risk, environmental triggers, and therapeutic advances, this review presents a framework for precision medicine in psoriasis.

Propranolol is currently the first-line therapy for infantile hemangioma (IH); however, its use is limited by notable adverse effects. The non-β-blocker enantiomer of propranolol, R-propranolol, represents a promising alternative for IH treatment. In this study, the efficacy of R-propranolol and its underlying mechanism in IH involution were investigated. The protein kinase RNA-like endoplasmic reticulum kinase (PERK) signaling pathway was required for the adipogenic potential of hemangioma stem cells (HemSCs), whereas prolonged PERK activation led to apoptosis. R-propranolol and racemic propranolol induce comparable HemSC adipogenesis. R-propranolol showed a stronger ability to disrupt protein homeostasis in HemSCs than racemic propranolol, as indicated by increased protein misfolding and enhanced activation of the PERK signaling pathway. Notably, R-propranolol induced HemSC apoptosis more effectively than racemic propranolol. This effect was attenuated by the PERK inhibitor GSK2606414. Immunostaining of clinical specimens further showed that PERK expression was higher in involuting IH samples than in proliferating IH samples. Together, these findings demonstrate that R-propranolol promotes adipogenesis and subsequent apoptosis of HemSCs through activation of the PERK signaling pathway.

Recent years have seen substantial scientific excitement in the role that the double-stranded DNA sensor and mediator of inflammation, stimulator of interferon genes (STING), plays in kidney disease. However, the STING pathway is not the sole regulator of inflammation, and STING has roles other than in inflammation. Here, elevated STING levels were observed in both human and mouse kidney disease, and the effects of STING deletion from kidney tubule cells, myeloid cells, and globally in experimental kidney disease were examined. Inflammatory gene up-regulation in tubule cells, induced by double-stranded DNA, was attenuated (but not negated) by STING knockout. Either myeloid or global knockout of STING marginally diminished fibroinflammatory gene up-regulation in mice with kidney injury caused by unilateral ureteral obstruction, whereas tubule cell knockout of STING unexpectedly augmented inflammatory gene up-regulation. Global knockout of STING similarly worsened diabetic kidney disease, likely due to heightened hyperglycemia. Antagonism of STING attenuated autophagy induction in human tubule cells, but not in human glomerular endothelial cells or podocytes. These findings serve as a counterweight to the enthusiasm that has recently emerged as to the roles of STING-mediated signaling in kidney disease. The actions of STING extend beyond its role in inflammation, and they are cell type dependent. STING may be a fine-tuner, but it is unlikely to be a prime mover, of inflammation in kidney disease.

Endotoxin-induced uveitis (EIU) is an experimental model of infectious uveitis, a condition that accounts for 14% of uveitis cases, with an incidence of 19 per 100,000 population per year in the United States. Infectious uveitis typically requires 4 to 6 weeks of treatment and may become chronic or recurrent. Current therapies include corticosteroids and empiric anti-infective agents but are limited by complications related to immunosuppression. In a mouse model of EIU, C-C motif chemokine ligand (Ccl)-2 deficiency markedly reduced EIU severity, indicating an important role for CCL2-driven inflammation. Neutrophils, or polymorphonuclear leukocytes (PMNs), are the dominant immune cells recruited in early-stage infectious uveitis, yet their interactions with C-C chemokine receptor (CCR)-2+ monocytes (monocytes that respond to CCL2), remain poorly understood. The role of PMNs in recruiting CCR2+ monocytes has not been studied in the mouse model. In the mouse EIU model, PMN depletion resulted in an increase in CCR2+ monocyte infiltration in the retina at peak disease, which persisted for 72 hours. PMN depletion improved the histology score in EIU mice but did not affect the clinical phenotype. In a more therapeutic approach, anti-platelet endothelial cell adhesion molecule (PECAM) antibody was used to block transmigration, demonstrating for the first time that transmigration in the retina is PECAM dependent. Anti-PECAM treatment resulted in the reduction of PMN accumulation in the retina as well as histologic and clinical manifestations of EIU.

The ability of the immune system to control malignant tumors depends in part on the migratory ability of CD8+ T cells. Developing in-depth cellular and molecular understanding into how changes in the structural organization of collagen-IV differentially governs site-specific CD8+ T-cell migration through restrictive tissue barriers is challenging given the dynamic biomechanical alterations occurring in the basement membranes of tumor blood vessels. Thus, uncovering new mechanisms regulating CD8+ T-cell migration through structurally altered or denatured collagen-IV may allow the development of clinically useful strategies to selectively enhance immune cell infiltration of tumors in a context-dependent manner. This work provides evidence that a secreted RGDKGE-containing collagen peptide limits CD8+ T-cell migration on denatured forms of collagen-IV, but not on normal triple helical collagen-IV by a unique mechanism. This novel pathway involves the context-dependent regulation of myosin IXB (MYO9B) and Yes-associated protein-1 (YAP) in CD8+ T cells, ultimately leading to altered F-actin polarization and selectively reduced migration on denatured collagen-IV that is enriched in basement membranes of tumor vessels. In addition to defining a previously unknown mechanism that contributes to the site-specific control of CD8+ T-cell migration, these studies provide a strategy to selectively reverse the inhibitory effects of this endogenously secreted collagen peptide using a function-blocking antibody, resulting in enhanced accumulation of CD8+ T cells in tumors growing in vivo.

By integrating transcriptomic data from The Cancer Genome Atlas, Gene Expression Omnibus, and a self-established colorectal cancer (CRC) cohort, it was identified that SYT8 is significantly up-regulated in tumors and is predictive of poor prognosis. Single-cell RNA sequencing, immunohistochemistry, and immunofluorescence experiments demonstrate that SYT8 expression is largely confined to tumor cells, predominantly in the nucleus. Functional assays reveal that depletion of SYT8 impairs, whereas its overexpression enhances, CRC cell proliferation and invasion. Transcriptomic profiling indicates an enrichment of cell cycle and epithelial-mesenchymal transition signatures. Mechanistically, co-immunoprecipitation/mass spectrometry identifies SETD1A as a direct SYT8-interacting partner. The SYT8-SETD1A axis forms a positive-feedback loop that increases H3K4me3 levels and drives the transcription of protumorigenic genes. Immune profiling further indicates that high SYT8 expression correlates with increased regulatory T-cell infiltration, suggesting an immunosuppressive microenvironment and potential resistance to immunotherapy. Collectively, SYT8 promotes CRC progression through the SETD1A/H3K4me3-mediated activation of the cell cycle, induction of epithelial-mesenchymal transition, and remodeling of the immune microenvironment. Therefore, SYT8 is established as a prognostic biomarker and serves as a therapeutic target in colorectal cancer.

Macrophages are critical regulators of inflammation with an essential role in maintaining and re-establishing homeostasis after inflammatory insults. However, excessive macrophage activation could promote fibrosis, highlighting their potential as a therapeutic target in chronic inflammatory diseases. Two preclinical models of systemic sclerosis, bleomycin-induced systemic scleroderma and sclerodermatous graft-versus-host disease, were used to analyze the role of macrophages in the establishment of fibrosis. In both models, macrophage numbers increase in the skin and lungs, in association with elevated collagen content and correlating with fibrosis development. These macrophages had a Ly6clowCD206+MerTk+ phenotype, suggesting a profibrotic role during disease progression. Using macrophage depletion and differentiation blocking approaches, this work shows that reduced macrophage accumulation effectively prevented bleomycin-induced fibrosis development. Direct profibrotic activity of bleomycin-exposed macrophages was revealed by s.c. macrophage injections in naïve mice, which was sufficient to induce systemic fibrosis. Finally, bleomycin-treated primary mouse and human macrophages display reduced clearance of apoptotic cells and secrete factors that promote fibroblast activation and collagen production. Metabolic and mitochondrial dysfunction, changes in receptor shedding, and cytoskeletal reorganization in bleomycin-treated macrophages further contribute to their impaired efferocytosis and enhanced profibrotic activity. Collectively, this work identifies macrophages as critical promoters of tissue fibrosis and suggests that inhibition of macrophage activation represents a new potent therapeutic avenue in efforts to reverse fibrosis associated with chronic inflammation.

Spatial profiling technologies are transforming our understanding of tissue organization by enabling high-resolution mapping of molecular features in situ. Spatial multi-omics platforms ranging from spot-based to single-cell and subcellular resolution are increasingly being integrated into pathobiological workflows, offering unprecedented insights into novel cellular states, the tissue microenvironment, cell-cell communication, drug resistance niches, and disease heterogeneity. This article discusses recent experimental and computational advances in spatial biology, highlighting how multimodal integration enables a more comprehensive understanding of tissue function and its dysregulation. The challenges and opportunities that arise in three-dimensional spatial mapping, the impact on biomarker discovery, therapeutic decision-making, and the translational implications of large-scale pathology foundation models trained on spatial omics data are explored. Finally, it's highlighted that refined biological questions, combined with artificial intelligence, can unlock the full potential of spatial omics and reshape diagnostic workflows toward more precise clinical decision-making.

Cutaneous dermal microvascular responses are critical to common inflammatory skin conditions and effective wound healing. However, few laboratory models effectively recreate the spatially intact microenvironment essential for genesis and function of the human dermal microcirculation. Recently, stem cell-derived skin organoids (SKOs) have been developed that possess many microanatomic and cellular features of native human skin, including hair-forming epidermis and an underlying dermal layer containing endothelial-lined channels. Here, temporal dynamics of human SKO vasculogenesis are profiled and organoid responses to inflammatory and traumatic stimuli are interrogated. SKOs generated from induced pluripotent stem cells expressing endothelial-specific green fluorescent protein develop vasculogenic foci by post-differentiation day 6 that evolved into extensive microvascular networks that persisted beyond 4 months in culture. Multiplex antibody arrays provided mechanistic insight into secreted effectors supporting early events in SKO vasculogenesis. Over time, SKO microvasculature became ensheathed by mural cells producing collagen IV-rich basement membranes, whereas endothelium retained signatures of proliferative activity/immaturity. Functionally, SKOs treated with proinflammatory cytokines expressed markers of endothelial and perivascular vascular activation, with concomitant release of endogenous inflammatory mediators. Finally, wounding of SKOs via sharp dissection provided the first demonstration of angiogenic healing responses that were further augmented by exogenous vascular endothelial growth factor. Overall, this advanced human culture system represents a highly relevant model for understanding biological responses by the dermal microvasculature.

Recent studies have shown that cancer-associated fibroblasts (CAFs), a key component of the tumor microenvironment, are heterogeneous and can be divided into distinct subsets. Although all CAFs were believed to promote tumor progression, recent studies have identified a distinguished subset of tumor-restraining CAFs (rCAFs). It was previously demonstrated that the up-regulation of Meflin (immunoglobulin superfamily containing leucine-rich repeat) expression confers a tumor-restraining role on CAFs in pancreatic, colon, urothelial, and lung cancers. Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer with a poor prognosis. In this study, it was shown that Meflin can be a candidate marker for rCAFs in TNBC. In co-culture experiments with tumor cells and fibroblasts, Meflin overexpression in fibroblasts inhibited tumor cell growth in a three-dimensional culture model and shifted their gene expression profile toward that characteristic of universal or normal fibroblasts. Meflin overexpression in fibroblasts significantly reduced the expression of the chemokine receptor ACKR3 and enhanced that of the prostaglandin synthase PTGDS. This is suggestive of the involvement of these proteins in tumor microenvironment regulation. Furthermore, Meflin deficiency reduced the area of tumor vessels in a TNBC mouse model, highlighting its role in CAF-mediated inhibition of TNBC progression and improvement of drug delivery. Accordingly, Meflin plays a role as a potential functional marker of rCAFs in TNBC.

Human corneal endothelial cells rarely proliferate after embryonic development and exhibit limited regenerative capacity following injury. Previous studies reveal that the expression level of growth differentiation factor 11 (GDF11) is higher in fetal corneal endothelium compared with that in adults. However, the role of GDF11 in corneal endothelium has not yet been investigated. This study explores GDF11's role in corneal endothelial injury repair. In a mouse corneal cryoinjury model, GDF11 expression increases following injury. In vivo, adeno-associated virus-mediated regulation of GDF11 accelerates injury repair by promoting proliferation (an increase in Ki-67-positive cells), thereby restoring corneal transparency and thickness. In vitro experiments, knocking down or overexpressing GDF11 in cells, reveal that it promotes cell proliferation by regulating the cell cycle, while enhancing cell migration and inhibiting apoptosis. After GDF11 overexpression, mRNA sequencing of the cryoinjured mouse corneal endothelium suggests that GDF11 is associated with cell proliferation and the Wnt signaling pathway. Through in vitro and in vivo experiments, it was discovered that GDF11 regulates the SRY-box transcription factor 9 (SOX9)-β-catenin axis to promote cell proliferation, thereby providing a novel therapeutic target for corneal endothelial diseases.

Intrahepatic bile ducts (IHBDs) form a complex hierarchical network essential for liver function. The remodeling and expansion of this network during ductular reaction (DR) are hallmarks of liver disease that can be key indicators of disease severity. Conventional histology fails to capture the full extent of IHBD structural changes after injury due to the complex three-dimensional (3D) organization of the IHBD network that limits understanding of DR, especially in human tissue. A major barrier to leveraging 3D imaging as a diagnostic tool is the absence of standardized pipelines for IHBD imaging and analysis. This work establishes a robust 3D IHBD imaging and analysis workflow, applying it to both mouse and human liver tissues. This pipeline enables quantification of tissue and individual duct ("segment") level features and identifies features of invasive and noninvasive DR. In mouse models, we uncover regional phenotypes, including IHBD diverticula-like structures after duct blockage and the formation of anastomosed clusters after hepatocellular injury. Finally, this 3D imaging and analysis workflow is applied to quantify IHBD networks in human liver tissue. This work deepens our understanding of IHBD architecture in homeostasis and injury, laying the groundwork for advanced phenotyping of IHBD morphologies in mice and humans with relevance to next-generation experimental and diagnostic approaches to liver disease.

Having the ability to objectively index dopamine (DA) levels in the brain with a peripheral biomarker of brain DA would enable the objective monitoring of the progression of Parkinson disease (PD) and other DA-dependent disorders. This study investigates this potential biomarker using a DA-depletion approach, the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) neurotoxin model and subjects with PD, which are well-known models of DA depletion in the midbrain of rodents and humans, respectively. MPTP-induced DA depletion in the substantia nigra compacta resulted in a significant decrease in DA and norepinephrine levels in the blood. The proportion of dopamine D2 receptor (D2R)-expressing leukocytes progressively decreased (specifically B and T cells) during the DA depletion. Subjects with PD displayed significantly decreased D2R expression in B and T cells, and increased levels in epinephrine, DA, norepinephrine, and levodopa, compared with control subjects. A significant negative correlation was found between blood levodopa and D2R expression in classical monocytes, which correlated mildly with blood DA levels. The modulation of peripheral D2Rs in PD and MPTP seen in this study demonstrates that substantia nigra compacta dopamine depletion in humans and rodents does manifest in the periphery. Although this study did not provide a clear narrative of how nigral and peripheral dopamine systems mirror each other, the results give evidence that peripheral D2Rs may be both biomarkers and important substrates for treatment of dopamine-dependent disorders.

Acute ischemic stroke is a complex disorder in which the damage goes beyond neuronal loss and involves dynamic responses from glial, vascular, stromal, and immune cells. Spatial transcriptomics (ST) has become a powerful tool to study these processes by preserving tissue architecture while revealing detailed gene expression patterns. This review describes how ST has advanced the understanding of cellular changes after stroke, focusing on microglia, astrocytes, and oligodendrocytes to showcase the complexity of stroke pathobiology. Research has shown that the glial cells adopt different states depending on location and time, influencing both harmful and protective outcomes, such as inflammation, blood-brain barrier damage, remyelination, and tissue repair. By combining ST with single-cell and multiomics approaches, new therapeutic targets have been identified, including different types of activated glial states, and key signaling pathways involved in glial communication. Despite the recent progress in ST, challenges remain, particularly the need for multi-time point analyses, three-dimensional reconstructions and standardized data sets that can move the field closer to clinical applications. Future reference atlases, together with experimental validation, will be essential for developing precise, cell-targeted therapies. This review summarizes the results from the most recent ST studies and highlights the possible applications of spatial approaches to improving stroke research and therapy.

Morule and squamous metaplasia are distinctive features of endometrial carcinoma (Em Ca). This study investigated the underlying molecular characteristics of these lesions, focusing on the deltaNp63 (p40) and ezrin-radixin-moesin-binding phosphoprotein 50 (EBP50)/S100A4/myosin heavy chain 9 (MYH9) axis. p40 expression was found at the transitions from morular to squamous metaplasia cells and in the basal/parabasal layers of squamous metaplastic epithelia. Cells stably overexpressing (OE) p40 increased expression of several cancer stem cell (CSC) markers (eg, CD44) and enhanced migration capability, suggesting that p40 induces a CSC phenotype. Expression of EBP50, S100A4, and MYH9 was significantly higher in squamous metaplastic cells compared with morular and surrounding carcinoma cells, along with enhanced interactions between MYH9 and either EBP50 or S100A4. EBP50 OE cells inhibited multinuclear/senescent features, even when MYH9 activity was inhibited; S100A4 OE cells displayed the opposite results. Inhibition of MYH9 in three-dimensional cultures led to elongated and apoptotic cells, likely due to disruption of the EBP50-MYH9 interaction. Finally, hypoxia-inducible factor-1α expression was significantly higher in squamous metaplasia, correlating positively with p40 and cytokeratin 5/6. Collectively, p40 is an initial signal for squamous metaplasia development from morular and surrounding carcinoma cells, by modulating CSC properties. This leads to terminal squamous differentiation through the MYH9 monomer-polymer equilibrium, regulated by EBP50 and S100A4 under hypoxic conditions.

Diagnostic pathology has long relied on the morphological interpretation of hematoxylin and eosin (H&E)-stained tissues to guide diagnosis and assess prognostic features. While pathologists intuitively recognize spatial patterns and architectural organization, these assessments remain largely qualitative and difficult to quantify systematically. Immunohistochemistry and immunofluorescence have introduced molecular specificity but are limited in multiplexing capacity, whereas bulk genomic and transcriptomic assays provide high molecular depth but lose spatial context by averaging signals across heterogeneous cell populations. Recent advances in spatial proteomics-including mass spectrometry-based imaging and cyclic immunofluorescence-now enable multiplexed, single-cell protein analysis within intact tissue architecture. These technologies have revealed complex immune and stromal microenvironments, spatially organized biomarkers predictive of therapeutic response, and molecular gradients underlying disease progression. By integrating histological and molecular information, spatial proteomics bridges traditional microscopy with high-dimensional omics, allowing quantitative, spatially resolved insights into tissue organization and disease mechanisms. This review summarizes recent developments in multiplexed spatial proteomics from both scientific and pathological perspectives, highlighting how these technologies extend beyond morphology to quantify histologic patterns, refine biomarker discovery, and facilitate clinical translation. The review also examines translational challenges and barriers to clinical implementation, including costs, standardization requirements, and workflow integration.