American Journal of Pathology最新文献

Tumor-associated macrophages (TAMs) play dual roles in tumor progression. TAMs are known to induce programmed death ligand-1 (PD-L1) expression in cancer cells. However, the regulatory effects of PD-L1 in melanoma cells on TAM phenotypical switching remain underexplored. Herein, our findings indicated that CD163 and MRC1 levels were significantly elevated in metastatic melanomas compared with primary melanomas, correlating with CD274 expression and predicted patient clinical outcomes. To study the mechanisms regulating M2-like polarization, PD-L1 was knocked out in both YUMM1.7 and B16-F10 melanoma cells. The data revealed that knocking out PD-L1 (PD-L1^KO) in melanoma resulted in a decelerated in vivo growth rate, accompanied by a significantly increased M1/M2 ratio, more dendritic cells, and enhanced activation of CD8⁺ T cells compared with wild-type (WT) melanoma cells. These alterations were associated with decreased expression of M2-associated chemokines (CCL2, CCL3, and CXCL2) and cytokines (IL6, IL10, and TGFβ1). Mice harboring PD-L1^KO melanomas exhibited elevated levels of CD8⁺ T cells in both the tumor-draining lymph nodes and the bloodstream compared with mice with PD-L1^WT melanomas. Treatment with extracellular vesicles (EVs) derived from PD-L1^KO melanoma resulted in a reduced tumor growth rate and fewer M2-like macrophages in the tumors compared with EVs from PD-L1^WT melanomas. Therefore, our data suggest that PD-L1 in melanoma and melanoma-derived EVs induces M2-like polarization, contributing to local and regional immune suppression.

CD44 is a transmembrane protein that plays an essential role in transducing extracellular stimuli into intracellular signaling cascades, especially in cancer cells. Recent studies have shown that CD44 contributes to metabolic regulation. However, the effect of CD44 on adipogenesis in white adipose tissue (WAT) remains unclear. Here, the results showed that the expression of CD44 was largely increased in the inguinal and epididymal WAT of obese mice. Ablation or neutralization of CD44 inhibits adipogenesis in cultured adipocytes. CD44-deficient mice are resistant to high-fat diet-induced obesity and metabolic dysfunction. RNA-sequencing, together with functional studies, revealed that reduced expression of tryptophan 5-hydroxylase 2 (Tph2) in WAT is responsible for the repressed adipogenesis in the absence of CD44. The application of 5-hydroxytryptamine, a product of TPH2, rescues the repressed adipogenesis induced by CD44 neutralization. Moreover, the inhibition of TPH2 by p-chlorophenylalanine recapitulates the beneficial phenotypes observed in CD44-deficient mice. Taken together, these data indicate that CD44 plays a pivotal role in adipogenesis in WAT. In this regard, CD44 and its downstream target TPH2 may hold great therapeutic potential for treating excessive adiposity-related metabolic disorders, such as obesity, insulin resistance, and type 2 diabetes.

Alterations in micro-RNAs, p53, and sphingolipid metabolism have been associated with head and neck squamous cell carcinoma (HNSCC). However, the role of sphingosine kinase (SK)-2, an enzyme crucial for sphingolipid metabolism, is poorly understood in HNSCC. The aim of this study was to investigate how SK2 and p53 interact to regulate miRNAs miR-205 and miR-296. Analysis of small-RNA sequencing data from nontumor oral keratinocytes with SK2 overexpression (NOK-SK2) compared to controls (NOK-Ø) revealed differential expression of >100 miRNAs being half-regulated by p53. The expression of miR-205 was down-regulated, and miR-296 was up-regulated, in NOK-SK2 cells; however, cells with SK2 knockdown and p53 overexpression showed an opposite profile. Proteins involved in miRNA biogenesis were increased in NOK-SK2 cells, while levels were decreased in NOK-SK2 cells with p53 overexpression. Transfection with miR-205 mimic and miR-296 inhibitor decreased the aggressiveness and cancer stem-like cells in oral keratinocytes and oral carcinoma cells with SK2 deregulation. Overexpression of miR-205 in HN12-SK2 cells decreased tumor-formation capacity, and NOK-SK2 cells abrogated tumor growth in mice. The results indicate crosstalk between SK2 and p53 in regulating miRNAs 205 and 296, which could be potential therapeutic targets in the treatment of HNSCC.

Endometrial cancer has the second highest incidence of malignant tumors in the female reproductive system, and accurate and efficient analysis of endometrial cancer pathology images is one of the important research components of computer-aided diagnosis. However, endometrial cancer pathology images have challenges such as smaller solid tumors, lesion areas varying in morphology, and difficulty distinguishing solid and nonsolid tumors, which would affect the accuracy of subsequent pathologic analyses. An Endometrial Cancer Multi-class Transformer Network (ECMTrans-net) is therefore proposed to improve the segmentation accuracy of endometrial cancer pathology images. An ECM-Attention module is first proposed, which can sequentially infer attention maps along three separate dimensions (channel, local spatial, and global spatial) and multiply the attention maps and the input feature map for adaptive feature refinement. This approach would solve the problems of the small size of solid tumors and similar characteristics of solid tumors to nonsolid tumors and further improve the accuracy of segmentation of solid tumors. In addition, an ECM-Transformer module is proposed, which can fuse multi-class feature information and dynamically adjust the receptive field, solving the issue of complex tumor features. Experiments on the Solid Tumor Endometrial Cancer Pathological (ST-ECP) data set found that performances of the ECMTrans-net is superior to state-of-the-art image segmentation methods, and the average values of accuracy, Mean Intersection over Union, precision, and Dice coefficients were 0.952, 0.927, 0.931, and 0.901, respectively.

Cystic fibrosis (CF) respiratory outcomes are heavily influenced by complications of infection. Pseudomonas aeruginosa and Staphylococcus aureus are the most common colonizers of the cystic fibrosis lung, and frequently overlap to cause chronic and persistent coinfections associated with severe disease. However, the dynamics of P. aeruginosa and S. aureus coinfection and its impacts on the development of CF lung structural damage are poorly understood. Additionally, small colony variants (SCVs) of S. aureus have been associated with P. aeruginosa infections in people with CF, but their role in disease progression is largely unknown. In this work, the CF rat was used to model chronic lung coinfection with P. aeruginosa and S. aureus, using clinically and laboratory-derived normal colony and SCV strains of S. aureus to evaluate the impact of phenotype on clinical outcomes. Rats coinfected with clinically derived S. aureus of both phenotypes experienced increased inflammation in the lung, but only the combination of P. aeruginosa and clinically normal colony S. aureus led to lung structural decline, including mucus obstruction and bronchiectasis. In regression analyses, damage was associated with a higher burden of P. aeruginosa, indicating that chronic coinfection with normal colony S. aureus and P. aeruginosa may support the progression CF lung decline driven by P. aeruginosa, which might be avoided when coinfecting S. aureus exhibits the SCV phenotype.

Diabetic retinopathy (DR) is the major ocular complication of diabetes caused by chronic hyperglycemia, which leads to incurable blindness. Currently, the effectiveness of therapeutic interventions is limited. This study aimed to investigate the function of piezo-type mechanosensitive ion channel component 1 (PIEZO1) and its potential regulatory mechanism in DR progression. The results showed that PIEZO1 expression was up-regulated in the retinal tissues of streptozotocin-induced diabetic mice and high-glucose (HG)-triggered Müller cells. Functionally, the knockdown of PIEZO1 improves the abnormal retinal function of diabetic mice and impedes inflammatory cytokine secretion and gliosis of Müller cells under HG conditions. Mechanistic investigations using RNA immunoprecipitation-real-time quantitative PCR, methylation RNA immunoprecipitation-real-time quantitative PCR, and luciferase reporter assays demonstrated that PIEZO1 was a downstream target of methyltransferase-like 3 (METTL3). These studies revealed that METTL3-mediated N6-methyladenosine (m6A) modification within the coding sequence of PIEZO1 mRNA significantly shortened its half-life. In HG-stimulated cells, there was a negative regulatory relationship between PIEZO1 and YTH domain family 2 (YTHDF2), a recognized m6A reader. The loss of YTHDF2 resulted in an extended half-life of PIEZO1 in cells with overexpression of METTL3, indicating that the effect of METTL3 on the mRNA stability of PIEZO1 was dependent on YTHDF2. Taken together, this study demonstrated the protective role of the PIEZO1 silencing in DR development, and the degradation of PIEZO1 mRNA is accelerated by METTL3/YTHDF2-mediated m6A modification.

Salivary gland neoplasms (SGNs) represent a group of human neoplasms characterized by a remarkable cytomorphologic diversity, which frequently poses diagnostic challenges. Accurate histologic categorization of salivary tumors is crucial to make precise diagnoses and guide decisions regarding patient management. Within the scope of this study, a computer-aided diagnosis model using Vision Transformer (ViT), a cutting-edge deep learning model in computer vision, has been developed to accurately classify the most prevalent subtypes of SGNs. These subtypes include pleomorphic adenoma, myoepithelioma, Warthin tumor, basal cell adenoma, oncocytic adenoma, cystadenoma, mucoepidermoid carcinoma, and salivary adenoid cystic carcinoma. The data set comprised 3046 whole slide images of histologically confirmed salivary gland tumors, encompassing nine distinct tissue categories. SGN-ViT exhibited impressive performance in classifying the eight salivary gland tumors, achieving an accuracy of 0.9966, an area under the receiver operating characteristic curve value of 0.9899, precision of 0.9848, recall of 0.9848, and an F1 score of 0.9848. When compared with benchmark models, SGN-ViT surpassed them in terms of diagnostic performance. In a subset of 100 whole slide images, SGN-ViT demonstrated comparable diagnostic performance to that of the chief pathologist while significantly reducing the diagnosis time, indicating that SGN-ViT held the potential to serve as a valuable computer-aided diagnostic tool for salivary tumors, enhancing the diagnostic accuracy of junior pathologists.

This study explores the mechanisms and combined effects of chronic peroxisome proliferator-activated receptor (PPAR)α/γ and cannabinoid receptor 2 (CB₂R) agonists on visceral adipose tissue (VAT)-derived extracellular vesicle (EV) release and associated systemic/VAT inflammation, decreased VAT capillary density/fibrosis, and intestinal inflammation/hyperpermeability in nonalcoholic steatohepatitis (NASH) mice. NASH mice received 1 month of PPARα/γ agonist aleglitazar (10 mg/kg per day) or CB₂R agonist JWH015 (3 mg/kg per day) alone or combined. High EV release from VAT of NASH mice was associated with severe systemic/VAT/intestinal inflammation, reduced capillary network of VAT, and intestinal hyperpermeability. Combined JWH015 with aleglitazar treatment significantly suppressed high-fat diet-induced obesity/adiposity, inhibited VAT expansion, reduced VAT inflammation/fibrosis, normalized VAT capillary network, and attenuated intestinal mucosal injury, inflammation, and hyperpermeability in NASH + aleglitazar + JWH015 mice. The inhibition of AT-derived EV release and hypoxia-inducible factor (HIF)1α levels in AT-derived EV, normalization of CB₂R, PPARα, PPARγ, PPARγ1, PPARγ2, tight junction proteins, vascular endothelial growth factor/CD31 expression, and down-regulation of HIF1α, monocyte chemoattractant protein-1, and transforming growth factor-β1 were observed in the VAT and intestine of the NASH + aleglitazar + jwh015 group. In vitro experiments revealed that PPARα/γ and CB₂R activation attenuated NASH AT-derived EV-induced pathogenic changes in the J774/SVEC4-10/Caco2/3T3-L1 cell system. This study suggested that VAT-derived EVs contribute to the pathogenesis of nonalcoholic fatty liver disease and that combined PPARα/γ and CB₂R agonist treatment reduces VAT-released EV release and HIF1/monocyte chemoattractant protein-1 signals to ameliorate hepatic steatosis and VAT/intestine abnormalities of NASH mice.

Alport syndrome is a rare kidney disease typically more severe in males due to its X-linked inheritance. However, female patients with heterozygous X-linked Alport syndrome (XLAS) can develop renal failure over time, necessitating accurate pathologic assessment for effective therapy. A key pathologic finding in female patients with XLAS is the mosaic pattern of partial loss of α5 chains of type IV collagen. This study, using a mouse model of XLAS with a nonsense mutation (R471∗) in the Col4a5 gene, analogous to human XLAS, aimed to examine the consistency of this pattern with the glomerular basement membrane (GBM) structure. A modified periodic acid-methenamine silver staining method was developed for clearer GBM visualization. The integrated images from COL4α5-stained fluorescence, periodic acid-methenamine silver, and low-vacuum scanning electron microscopy into a single-slide section and applied supervised deep learning to predict GBM lesions. Results showed significant individual variability in urinary protein levels and histologic lesions. Pathologic parameters, including crescent formation, focal segmental glomerulosclerosis, and the COL4α5/α2 ratio, correlated with clinical parameters like urinary protein and plasma creatinine levels. Integrated low-vacuum scanning electron microscopy analysis revealed dense GBM regions corresponded to areas where COL4α5 was preserved, whereas coarse GBM (basket-weave lesions) occurred in COL4α5-deficient regions. These advanced techniques can enhance biopsy-based diagnosis of Alport syndrome and aid in developing artificial intelligence diagnostic tools for diseases involving basement membrane lesions.