American Journal of Pathology最新文献

Ferredoxin 1 and 2 (FDX1/2) constitute an evolutionarily conserved FDX family of iron-sulfur cluster-containing proteins. FDX1/2 are cognate substrates of ferredoxin reductase and serve as conduits for electron transfer from NADPH to a set of proteins involved in biogenesis of corticosteroids, hemes, iron-sulfur cluster, and lipoylated proteins. Recently, we showed that Fdx1 is essential for embryonic development and lipid homeostasis. To explore the physiological role of FDX2, we generated Fdx2-deficient mice. Interestingly, we found that unlike Fdx1-null embryos, which were dead at embryonic day 10.5 to 13.5, Fdx2-null mice were viable. We also found that both Fdx2-null and Fdx2-heterozygous mice had a short lifespan and were susceptible to spontaneous tumors and steatohepatitis. Moreover, we found that FDX2 deficiency increased, whereas overexpression of FDX2 decreased cytoplasmic accumulation of lipid droplets. Consistently, we found that FDX2 deficiency led to accumulation of cholesterol and triglycerides. Mechanistically, we found that FDX2 deficiency suppressed expression of cholesterol transporter ABCA1 and activated master lipid transcription regulators sterol regulatory element-binding proteins 1/2, thus leading to altered lipid metabolism. Untargeted lipidomic analysis showed that FDX2 deficiency led to altered biosynthesis of various lipid classes, including cardiolipins, cholesterol, ceramides, triglycerides, and fatty acids. In summary, our findings underline an indispensable role of FDX2 in tumor suppression and lipid homeostasis at both cellular and organismal levels without being a prerequisite for embryonic development.

The gut microbiota plays a crucial regulatory role in various physiological processes, yet its impact on corneal homeostasis remains insufficiently understood. Here, we investigate the effects of antibiotic-induced gut dysbiosis (AIGD) and germ-free conditions on circadian gene expression, barrier integrity, nerve density, and immune cell activity in the corneas of mice. Through RNA sequencing, we found that both AIGD and germ-free conditions significantly disrupted the overall transcriptomic profile and circadian transcriptomic oscillations in the cornea. These molecular disturbances were accompanied by a reduction in corneal epithelial thickness, nerve density, corneal sensitivity, and compromised barrier function. Notably, supplementation with short-chain fatty acids (SCFAs) significantly restored corneal integrity in AIGD mice. Further single-cell sequencing revealed that SCFA receptors G-protein-coupled receptor 109A (Hcar2), olfactory receptor 78 (Olfr78), and G-protein-coupled receptor 43 (Ffar2) are expressed in corneal epithelial basal cells, embryonically derived macrophages, perivascular cells, and γδ T cells, respectively. In conclusion, this study demonstrates that the gut microbiota plays a critical role in corneal physiology by regulating circadian gene expression and maintaining barrier function. These findings enhance our understanding of the gut-eye axis, highlighting the cornea as a target for microbiota-derived metabolic signals and underlining the potential therapeutic value of SCFAs in treating corneal dysfunction.

Understanding the tumor hypoxic microenvironment is crucial for grasping tumor biology, clinical progression, and treatment responses. This study presents a novel application of artificial intelligence in computational histopathology to evaluate hypoxia in breast cancer. Weakly supervised deep learning models can accurately detect morphologic changes associated with hypoxia in routine hematoxylin and eosin (H&E)-stained whole slide images (WSIs). Our model, HypOxNet, was trained on H&E-stained WSIs from breast cancer primary sites (n = 1016) at ×40 magnification using data from The Cancer Genome Atlas. We used the Hypoxia Buffa signature to measure hypoxia scores, which ranged from -43 to 47, and stratified the samples into hypoxic and normoxic based on these scores. This stratification represented the weak labels associated with each WSI. HypOxNet achieved an average area under the curve of 0.82 on test sets, identifying significant differences in cell morphology between hypoxic and normoxic tissue regions. Importantly, once trained, the HypOxNet model requires only the readily available H&E-stained slides, making it especially valuable in low-resource settings where additional gene expression assays are not available. These artificial intelligence-based hypoxia detection models can potentially be extended to other tumor types and seamlessly integrated into pathology workflows, offering a fast, cost-effective alternative to molecular testing.

Tissue inhibitors of metalloproteinases (TIMPs) modulate extracellular matrix (ECM) remodeling for maintaining homeostasis and promoting cell migration and proliferation. Pathological conditions can alter TIMP homeostasis and aggravate disease progression. The roles of TIMPs have been studied in tissue-related disorders; however, their contributions to tissue repair during corneal injury are undefined. Here, the TIMP expression in human corneal epithelial (HCLE) cells under homeostatic and inflammatory milieus was profiled to examine their contribution to the healing of injured cornea epithelia. Transcriptionally, TIMP-2 was highly expressed in HCLE when stimulated with 100 ng/mL IL-1β or scratch-wounded. Unlike TIMP-1, recombinant TIMP-2 (rTIMP-2) significantly promoted epithelial cell wound closure compared to untreated and TIMP-2-neutralizing conditions. At 12 hours, the Ki-67+ cells significantly increased 3-fold compared to untreated cells, suggesting that rTIMP-2 is associated with cell proliferation. Furthermore, rTIMP-2 treatment significantly suppressed inflammatory cytokine expression (IL-1β, IL-6, IL-8, and TNFα) and injury-induced matrix metalloproteinases (MMP-1, -2, -3, -9, -10, and -13). Topical treatment of injured mouse cornea with 0.1 mg/mL rTIMP-2 significantly promoted corneal re-epithelialization and improved tissue integrity. The treatment suppressed the expression of inflammatory cytokines and MMPs, as well as the infiltration of neutrophils at the injury site. These findings indicate that TIMP-2 promotes faster wound healing by suppressing injury-induced inflammation and MMP expression, suggesting a potential therapeutic target for corneal wound management.

This study aimed to investigate the expression of glucagon-like peptide 1 receptor (GLP-1R) in the lacrimal gland and explore the effects of topical application of GLP-1R agonist on lacrimal gland function in a murine model of type 1 diabetes. Tear secretion was evaluated using phenol red threads, RNA sequencing was used to explore gene expression profiles associated with hyperglycemia-induced lacrimal gland injuries, and histologic analysis was conducted to evaluate the degree of damage. The expression of GLP-1R in the lacrimal gland was first identified, and a down-regulation trend associated with diabetes was observed. RNA-sequencing data from lacrimal gland tissues revealed that differentially expressed genes were enriched in inflammatory response pathways. Histologic analysis demonstrated persistent hyperglycemia-induced infiltration of inflammatory cells and progressive fibrosis in the lacrimal gland, resulting in atrophy and diminished tear secretion. Topical application of liraglutide effectively attenuated inflammation and alleviated fibrosis, thus promoting tear production in diabetic mice. Additionally, local intervention with liraglutide could promote autophagy degradation function in the lacrimal gland. This study represents the first validation of GLP-1R expression in the lacrimal gland and its down-regulation induced by diabetes; furthermore, these findings demonstrate that topical administration of liraglutide eye drops, a GLP-1R agonist, can effectively mitigate hyperglycemia-induced damage in the lacrimal gland while enhancing tear secretion.