Atmospheric emissions of particulate matter-bound heavy metals from industrial sources.

Although industrial activities are significant contributors to atmospheric releases of particulate matter (PM) and associated toxic substances that lead to adverse human health effects, a knowledge gap exists concerning the human health risk resulting from such activities owing to lack of evaluation of industrial emissions. Here, we comprehensively characterized and quantified PM from 118 full-scale industrial plants. The dominant (97.9 %) PM showed diameters of <2.5 µm; 79.0 % had diameters below 1 µm. Annual atmospheric releases of Fe and heavy metals (As, Cd, Cr, Cu, Ni, Pb, Zn) contained in fine PM from these global industrial activities are estimated to be 51,161 t and 69,591 t, respectively. Emissions of heavy metals from these industries cause increased cancer risk, estimated to range from 1461 % to 50,752 %. Five crystalline compounds (ZnO, PbSO4, Mn3O4, Fe3O4, Fe2O3) that can indicate specific industrial sources are identified. Global annual emissions of these toxic compounds in fine PM from the industrial sources are estimated to be 78,635 t. The Global South displayed higher emissions than the Global North. These results are significant for recognizing regional health risks of industrial emissions.

Reduction of relative intensity noise in a diamond Raman laser.

The relative intensity noise (RIN) characteristics of a continuous-wave diamond Raman laser are investigated for the first time. The results reveal the parasitic stimulated Brillouin scattering (SBS) that usually occurred with higher-order spatial modes in the diamond Raman resonator is a pivotal factor impacting the Raman longitudinal modes and deteriorating the RIN level. The diamond Raman laser automatically switches to single-longitudinal-mode operation and the RIN level is significantly decreased in the frequency range of 200 Hz to 1 MHz after the parasitic SBS is effectively suppressed through inserting a spatial aperture or a χ(2) nonlinear crystal into the cavity. Due to the introduction of additional nonlinear loss to the high intensity Raman fluctuations and the non-lasing spontaneous Raman modes, the χ(2) nonlinear crystal enables better performance in the RIN-level reduction compared to the spatial aperture which can only achieve SBS inhibition. The RIN reduction routes are well suited for various crystalline Raman media to achieve high power and low intensity noise laser at different wavelengths.

Atmospheric emissions of hexachlorobutadiene in fine particulate matter from industrial sources.

Hexachlorobutadiene (HCBD) is a concerning chemical that is included in the United States Toxic Substances Control Act, and the Stockholm Convention. Knowledge of the sources of HCBD is insufficient and is pivotal for accurate inventory and implementing global action. In this study, unintentional HCBD release and source emission factors of 121 full-scale industrial plants from 12 industries are investigated. Secondary copper smelting, electric arc furnace steelmaking, and hazardous waste incineration show potential for large emission reductions, which are found of high HCBD emission concentrations of > 20 ng/g in fine particulate matter in this study. The highest HCBD emission concentration is observed for the secondary copper smelting industry (average: 1380 ng/g). Source emission factors of HCBD for the 12 industries range from 0.008 kg/t for coal fire power plants to 0.680 kg/t for secondary lead smelting, from which an estimation of approximately 8452.8 g HCBD emissions annually worldwide achieved. The carcinogenic risks caused by HCBD emissions from countries and regions with intensive 12 industrial sources are 1.0-80 times higher than that without these industries. These results will be useful for formulating effective strategies of HCBD control.

Scattered Crypt Intestinal Epithelial Cell Apoptosis Induces Necrotizing Enterocolitis Via Intricate Mechanisms.

BACKGROUND & AIMS: Necrotizing enterocolitis (NEC) is a life-threatening disease affecting mostly the ileum of preemies. Intestinal epithelial cell (IEC) apoptosis contributes to NEC pathogenesis. However, how scattered crypt IEC apoptosis leads to NEC with excessive villus epithelial necrosis remains unclear. METHODS: A novel triple-transgenic mouse model, namely, 3xTg-iAPcIEC (inducible apoptosis phenotype in crypt-IEC), was developed to induce IEC-specific overexpression of Fasl transgene using doxycycline (Dox)-inducible tetO-rtTA system and villin-cre technology. The 3-days-old neonatal 3xTg-iAPcIEC mice and their littermate controls were subcutaneously (s.c.) challenged with a single dose of Dox. Intestinal tissues were processed at different time points to examine scattered crypt IEC apoptosis-mediated NEC development. Gene knockout technology, antibody-mediated cell depletion, and antibiotic-facilitated Gram-positive bacteria depletion were used to study mechanisms. RESULTS: Treatment of 3xTg-iAPcIEC mouse pups with Dox induces scattered crypt IEC apoptosis followed by crypt inflammation and excessive villous necrosis resembling NEC. This progression correlated with elevated Ifng, Rip3, CD8+ T cells, and Gram-positive bacteria in the ileum. Mechanistically, IFN-γ and RIP3-activated signals mediate the effect of scattered crypt IEC apoptosis on the induction of intestinal crypt inflammation and villous necrosis. Meanwhile, pathophysiological events of CD8+ T cell infiltration and dysbiosis with Gram-positive bacteria primarily contribute to excessive villous inflammation and necrosis. Notably, blocking any of these events protects against NEC development in 3xTg-iAPcIEC mouse pups, underlining their central roles in NEC pathogenesis. CONCLUSIONS: Scattered crypt IEC apoptosis induces NEC in mouse pups via IFN-γ, RIP3, CD8+ T cells, and Gram-positive bacteria-mediated comprehensive pathophysiological events. Our findings may advance knowledge in the prevention and treatment of NEC.

Granular Biphasic Colloidal Hydrogels for 3D Bioprinting.

Granular hydrogels composed of hydrogel microparticles are promising candidates for 3D bioprinting due to their ability to protect encapsulated cells. However, to achieve high print fidelity, hydrogel microparticles need to jam to exhibit shear-thinning characteristics, which is crucial for 3D printing. Unfortunately, this overpacking can significantly impact cell viability, thereby negating the primary advantage of using hydrogel microparticles to shield cells from shear forces. To overcome this challenge, a novel solution: a biphasic, granular colloidal bioink designed to optimize cell viability and printing fidelity is introduced. The biphasic ink consists of cell-laden polyethylene glycol (PEG) hydrogel microparticles embedded in a continuous gelatin methacryloyl (GelMA)-nanosilicate colloidal network. Here, it is demonstrated that this biphasic bioink offers outstanding rheological properties, print fidelity, and structural stability. Furthermore, its utility for engineering complex tissues with multiple cell types and heterogeneous microenvironments is demonstrated, by incorporating ß-islet cells into the PEG microparticles and endothelial cells in the GelMA-nanosilicate colloidal network. Using this approach, it is possible to induce cell patterning, enhance vascularization, and direct cellular function. The proposed biphasic bioink holds significant potential for numerous emerging biomedical applications, including tissue engineering and disease modeling.

GHSR Deletion in ß-Cells of Male Mice: Ineffective in Obesity, but Effective in Protecting against Streptozotocin-Induced ß-Cell Injury in Aging.

Insulin secretion from pancreatic ß cells is a key pillar of glucose homeostasis, which is impaired under obesity and aging. Growth hormone secretagogue receptor (GHSR) is the receptor of nutrient-sensing hormone ghrelin. Previously, we showed that ß-cell GHSR regulated glucose-stimulated insulin secretion (GSIS) in young mice. In the current study, we further investigated the effects of GHSR on insulin secretion in male mice under diet-induced obesity (DIO) and streptozotocin (STZ)-induced ß-cell injury in aging. ß-cell-specific-Ghsr-deficient (Ghsr-ßKO) mice exhibited no glycemic phenotype under DIO but showed significantly improved ex vivo GSIS in aging. We also detected reduced insulin sensitivity and impaired insulin secretion during aging both in vivo and ex vivo. Accordingly, there were age-related alterations in expression of glucose transporter, insulin signaling pathway, and inflammatory genes. To further determine whether GHSR deficiency affected ß-cell susceptibility to acute injury, young, middle-aged, and old Ghsr-ßKO mice were subjected to STZ. We found that middle-aged and old Ghsr-ßKO mice were protected from STZ-induced hyperglycemia and impaired insulin secretion, correlated with increased expression of insulin signaling regulators but decreased pro-inflammatory cytokines in pancreatic islets. Collectively, our findings indicate that ß-cell GHSR has a major impact on insulin secretion in aging but not obesity, and GHSR deficiency protects against STZ-induced ß-cell injury in aging.

ZnPP-laden nanoparticles improve glucose homeostasis and chronic inflammation during obesity.

BACKGROUND AND PURPOSE: Chronic inflammation plays a pivotal role in the development of Type 2 diabetes mellitus (T2DM). Previous studies have shown that haem oxygenase-1 (HO-1) plays a proinflammatory role during metabolic stress, suggesting that HO-1 inhibition could be an effective strategy to treat T2DM. However, the application of HO-1 inhibitors is restricted due to solubility-limited bioavailability. In this study, we encapsulated the HO-1 inhibitor, zinc protoporphyrin IX (ZnPP), within nanoparticles and investigated their role in regulating glucose homeostasis and chronic inflammation during obesity. EXPERIMENTAL APPROACH: We delivered DMSO-dissolved ZnPP (DMSO-ZnPP) and ZnPP-laden nanoparticles (Nano-ZnPP) to diet-induced obese male mice for 6 weeks. Glucose and insulin tolerance tests were carried out, liver and adipose tissue gene expression profiles analysed, and systemic inflammation analysed using flow cytometry. KEY RESULTS: Nanoparticles significantly increased the delivery efficiency of ZnPP in both cells and mice. In mice with diet-induced obesity, inhibition of HO-1 by Nano-ZnPP significantly decreased adiposity, increased insulin sensitivity, and improved glucose tolerance. Moreover, Nano-ZnPP treatment attenuated both local and systemic inflammatory levels during obesity. Mechanistically, Nano-ZnPP significantly attenuated glucagon, TNF, and fatty acid synthesis signalling pathways in the liver. In white adipose tissue, the oxidative phosphorylation signalling pathway was enhanced and the inflammation signalling pathway diminished by Nano-ZnPP. Our results show that Nano-ZnPP has better effects on the improvement of glucose homeostasis and attenuation of chronic inflammation, than those of DMSO-dissolved ZnPP. CONCLUSIONS AND IMPLICATIONS: These findings indicate that ZnPP-laden nanoparticles are potential therapeutic agents for treating T2DM.

Colonic Dysregulation of Major Metabolic Pathways in Experimental Ulcerative Colitis.

Inflammatory bowel disease (IBD) is multifactorial chronic inflammatory disease in the gastrointestinal tract, affecting patients' quality of life profoundly. The incidence of IBD has been on the rise globally for the last two decades. Because the molecular mechanisms underlying the disease remain not well understood, therapeutic development is significantly impeded. Metabolism is a crucial cellular process to generate the energy needed for an inflammatory response and tissue repair. Comprehensive understanding of the metabolic pathways in IBD would help to unravel the disease pathogenesis/progression and facilitate therapeutic discoveries. Here, we investigated four metabolic pathways altered in experimental colitis. C57BL/6J mice were treated with dextran sulfate sodium (DSS) in drinking water for 7 days to induce experimental ulcerative colitis (UC). We conducted proteomics analysis for the colon samples using LC/MS, to profile key metabolic intermediates. Our findings revealed significant alterations in four major metabolic pathways: antioxidative defense, ß-oxidation, glycolysis, and TCA cycle pathways. The energy metabolism by ß-oxidation, glycolysis, and TCA cycle pathways were downregulated under UC, together with reduced antioxidative defense pathways. These results reveal metabolic re-programming in intestinal cells under UC, showing dysregulation in all four major metabolic pathways. Our study underscores the importance of metabolic drivers in the pathogenesis of IBD and suggests that the modification of metabolism may serve as a novel diagnostic/therapeutic approach for IBD.

Endothelial specific prolyl hydroxylase domain-containing protein 2 deficiency attenuates aging-related obesity and exercise intolerance.

Obesity and exercise intolerance greatly reduce the life quality of older people. Prolyl hydroxylase domain-containing protein 2 (PHD2) is an important enzyme in modulating hypoxia-inducible factor-alpha (HIF) protein. Using vascular endothelial cell-specific PHD2 gene knockout (PHD2 ECKO) mice, we investigated the role of endothelial PHD2 in aging-related obesity and exercise capacity. Briefly, PHD2 ECKO mice were obtained by crossing PHD2-floxed mice with VE-Cadherin (Cdh5)-Cre transgenic mice. The effect of PHD2 ECKO on obesity and exercise capacity in PHD2 ECKO mice and control PHD2f/f mice were determined in young mice (6 to 7 months) and aged mice (16-18 months). We found that aged PHD2 ECKO mice, but not young mice, exhibited a lean phenotype, characterized by lower fat mass, and its ratio to lean weight, body weight, or tibial length, while their food uptake was not reduced compared with controls. Moreover, as compared with aged control mice, aged PHD2 ECKO mice exhibited increased oxygen consumption at rest and during exercise, and the maximum rate of oxygen consumption (VO2 max) during exercise. Furthermore, as compared with corresponding control mice, both young and aged PHD2 ECKO mice demonstrated improved glucose tolerance and lower insulin resistance. Together, these data demonstrate that inhibition of vascular endothelial PHD2 signaling significantly attenuates aging-related obesity, exercise intolerance, and glucose intolerance.

Neuronal ablation of GHSR mitigates diet-induced depression and memory impairment via AMPK-autophagy signaling-mediated inflammation.

Obesity is associated with chronic inflammation in the central nervous system (CNS), and neuroinflammation has been shown to have detrimental effects on mood and cognition. The growth hormone secretagogue receptor (GHSR), the biologically relevant receptor of the orexigenic hormone ghrelin, is primarily expressed in the brain. Our previous study showed that neuronal GHSR deletion prevents high-fat diet-induced obesity (DIO). Here, we investigated the effect of neuronal GHSR deletion on emotional and cognitive functions in DIO. The neuron-specific GHSR-deficient mice exhibited reduced depression and improved spatial memory compared to littermate controls under DIO. We further examined the cortex and hippocampus, the major regions regulating cognitive and emotional behaviors, and found that the neuronal deletion of GHSR reduced DIO-induced neuroinflammation by suppressing proinflammatory chemokines/cytokines and decreasing microglial activation. Furthermore, our data showed that neuronal GHSR deletion suppresses neuroinflammation by downregulating AMPK-autophagy signaling in neurons. In conclusion, our data reveal that neuronal GHSR inhibition protects against DIO-induced depressive-like behavior and spatial cognitive dysfunction, at least in part, through AMPK-autophagy signaling-mediated neuroinflammation.

Precision targeting of CuET overload to disrupt mitochondrial unfolded protein response by integrated liposome.

Mitochondria in breast cancer play a critical role in survival and adaptation to dynamic environments. Thus, targeting mitochondria emerges as a promising therapeutic strategy for breast cancer. However, the adaptive unfolded protein response in mitochondria (UPRmt) due to mitochondrial unspecific distribution might contribute to diminished therapeutic outcomes. Herein, mitochondrial targeting liposome agents (CTPP-Lipid) are constructed and adopted for delivering the copper ion (CuET-DSF), which is especially sensitive for mitochondria-abundant breast tumors. In brief, the CTPP-Lipid@CuET achieves the goal of Cu2+ overloading by mitochondria targeting delivery. This rapidly increases ROS production, disrupts mitochondrial structure, and avoids the adaptive UPRmt formation, finally leading to apoptosis of breast cancer cells. In general, the Cu2+ overloading at mitochondria by CTPP-Lipid@CuET is a potential strategy for antitumor therapy, providing new insights into breast tumor therapy.

Telmisartan loading thermosensitive hydrogel repairs gut epithelial barrier for alleviating inflammatory bowel disease.

Inflammatory bowel disease (IBD) remains a global health concern with a complex and incompletely understood pathogenesis. In the course of IBD development, damage to intestinal epithelial cells and a reduction in the expression of tight junction (TJ) proteins compromise the integrity of the intestinal barrier, exacerbating inflammation. Notably, the renin-angiotensin system and angiotensin II receptor type 1 (AT1R) play a crucial role in regulating the pathological progression including vascular permeability, and immune microenvironment. Thus, Telmisartan (Tel), an AT1R inhibitor, loading thermosensitive hydrogel was constructed to investigate the potential of alleviating inflammatory bowel disease through rectal administration. The constructed hydrogel exhibits an advantageous property of rapid transformation from a solution to a gel state at 37°C, facilitating prolonged drug retention within the gut while mitigating irritation associated with rectal administration. Results indicate that Tel also exhibits a beneficial effect in ameliorating colon shortening, colon wall thickening, cup cell lacking, crypt disappearance, and inflammatory cell infiltration into the mucosa in colitis mice. Moreover, it significantly upregulates the expression of TJ proteins in colonic tissues thereby repairing the intestinal barrier damage and alleviating the ulcerative colitis (UC) disease process. In conclusion, Tel-loaded hydrogel demonstrates substantial promise as a potential treatment modality for IBD.

NOS-like activity of CeO2 nanozymes contributes to diminishing the vascular plaques.

Ceria nanoparticles (CeO2NPs) exhibit great potential in cardiovascular disease and nonalcoholic fatty liver disease due to its excellent antioxidant capacity. However, the profitable effect of CeO2NPs on many diseases is almost all attributed to the regulation of ROS. Apart from the general antioxidant function, there seems to be no more distinct mechanism to reflect its unique multi-disease improvement effect. Here, we for the first time reveal a new discovery of CeO2NPs in mimicking nitric oxide synthase (NOS) by catalyzing L-arginine (L-Arg) to produce nitric oxide (NO) or the derivatives. NOS-like activity of CeO2NPs is original and associated with multiple factors like substrate concentration, pH, temperature and time, etc. where oxygen vacancy ratio plays a more critical role. Meanwhile, NOS-like activity of CeO2NPs successfully elevates NO secretion in endothelial cells and macrophages without expanding eNOS/iNOS expression. Importantly, NOS-like activity of CeO2NPs and the responsive endogenous NO promote the re-distribution of blood lipids and stabilize eNOS expression but suppress iNOS, thus collectively alleviate the accumulation of vascular plaque. Altogether, we provide a new angle of view to survey the outstanding potential of CeO2NPs, apart from the inevitable antioxidant capacity, the covert but possible and more critical NOS-like enzymatic activity is more noteworthy.

Growth and Temperature Properties of the Phase-Matching Angle of 23% Deuterated ADP Crystal.

Theoretical analysis indicated that partially deuterated ammonium dihydrogen phosphate (DADP) crystal with a deuterium content of 23% could realize spectral noncritical phase-matching (S-NCPM) for type-I frequency doubling of an Nd:glass laser. To explore the temperature dependence of the phase matching (PM) angle of the second harmonic generation (SHG) process and the output SHG bandwidth of DADP crystal at 1.053 µm, we used the point-seed rapid-growth method to grow targeted DADP crystal with 23% deuterium content. Experimental results indicated that the grown DADP crystal had high quality and large dimensions (7 × 6 × 6 cm3). Using a femtosecond OPO laser as a tunable light source, the temperature dependence of the PM angle of the SHG process in DADP crystal at 1.053 µm was investigated. The PM angle changed linearly with temperature, as predicted by the theoretical calculation. In addition, under the condition of higher temperature, broad bandwidths of the second harmonic of DADP crystal were still observed. These results provide excellent guidance and reference value for the application of wavelength insensitive phase-matched second harmonic generation in partially deuterated DADP.

Hepatocyte FoxO1 Deficiency Protects From Liver Fibrosis via Reducing Inflammation and TGF-ß1-mediated HSC Activation.

BACKGROUND & AIMS: The O-class of the forkhead transcription factor FoxO1 is a crucial factor mediating insulin→PI3K→Akt signaling and governs diverse cellular processes. However, the role of hepatocyte FoxO1 in liver fibrosis has not been well-established. In his study, we investigated the role of hepatocyte FoxO1 in liver fibrosis and uncovered the underlying mechanisms. METHODS: Liver fibrosis was established by carbon tetrachloride (CCL4) administration and compared between liver-specific deletion of FoxO1 deletion (F1KO) and control (CNTR) mice. Using genetic and bioinformatic strategies in vitro and in vivo, the role of hepatic FoxO1 in liver fibrosis and associated mechanisms was established. RESULTS: Increased FoxO1 expression and FoxO1 signaling activation were observed in CCL4-induced fibrosis. Hepatic FoxO1 deletion largely attenuated CCL4-induced liver injury and fibrosis compared with CNTR mice. F1KO mice showed ameliorated CCL4-induced hepatic inflammation and decreased TGF-ß1 mRNA and protein levels compared with those of CNTR mice. In primary hepatocytes, FoxO1 deficiency reduced TGF-ß1 expression and secretion. Conditioned medium (CM) collected from wild-type hepatocytes treated with CCL4 activated human HSC cell line (LX-2); such effect was attenuated by FoxO1 deletion in primary hepatocytes or neutralization of TGF-ß1 in the CM using TGF-ß1 antibody. Hepatic FoxO1 overexpression in CNTR mice promoted CCL4-induced HSC activation; such effect was blocked in L-TGF-ß1KO mice. CONCLUSIONS: Hepatic FoxO1 mediates CCL4-inducled liver fibrosis via upregulating hepatocyte TGF-ß1 expression, stimulating hepatic inflammation and TGF-ß1-mediated HSC activation. Hepatic FoxO1 may be a therapeutic target for prevention and treatment of liver fibrosis.

Nutrient-sensing growth hormone secretagogue receptor in macrophage programming and meta-inflammation.

OBJECTIVE: Obesity-associated chronic inflammation, aka meta-inflammation, is a key pathogenic driver for obesity-associated comorbidity. Growth hormone secretagogue receptor (GHSR) is known to mediate the effects of nutrient-sensing hormone ghrelin in food intake and fat deposition. We previously reported that global Ghsr ablation protects against diet-induced inflammation and insulin resistance, but the site(s) of action and mechanism are unknown. Macrophages are key drivers of meta-inflammation. To unravel the role of GHSR in macrophages, we generated myeloid-specific Ghsr knockout mice (LysM-Cre;Ghsrf/f). METHODS: LysM-Cre;Ghsrf/f and control Ghsrf/f mice were subjected to 5 months of high-fat diet (HFD) feeding to induce obesity. In vivo, metabolic profiling of food intake, physical activity, and energy expenditure, as well as glucose and insulin tolerance tests (GTT and ITT) were performed. At termination, peritoneal macrophages (PMs), epididymal white adipose tissue (eWAT), and liver were analyzed by flow cytometry and histology. For ex vivo studies, bone marrow-derived macrophages (BMDMs) were generated from the mice and treated with palmitic acid (PA) or lipopolysaccharide (LPS). For in vitro studies, macrophage RAW264.7 cells with Ghsr overexpression or Insulin receptor substrate 2 (Irs2) knockdown were studied. RESULTS: We found that Ghsr expression in PMs was increased under HFD feeding. In vivo, HFD-fed LysM-Cre;Ghsrf/f mice exhibited significantly attenuated systemic inflammation and insulin resistance without affecting food intake or body weight. Tissue analysis showed that HFD-fed LysM-Cre;Ghsrf/f mice have significantly decreased monocyte/macrophage infiltration, pro-inflammatory activation, and lipid accumulation, showing elevated lipid-associated macrophages (LAMs) in eWAT and liver. Ex vivo, Ghsr-deficient macrophages protected against PA- or LPS-induced pro-inflammatory polarization, showing reduced glycolysis, increased fatty acid oxidation, and decreased NF-κB nuclear translocation. At molecular level, GHSR metabolically programs macrophage polarization through PKA-CREB-IRS2-AKT2 signaling pathway. CONCLUSIONS: These novel results demonstrate that macrophage GHSR plays a key role in the pathogenesis of meta-inflammation, and macrophage GHSR promotes macrophage infiltration and induces pro-inflammatory polarization. These exciting findings suggest that GHSR may serve as a novel immunotherapeutic target for the treatment of obesity and its associated comorbidity.

New prospects of cancer therapy based on pyroptosis and pyroptosis inducers.

Pyroptosis is a gasdermin-mediated programmed cell death (PCD) pathway. It differs from apoptosis because of the secretion of inflammatory molecules. Pyroptosis is closely associated with various malignant tumors. Recent studies have demonstrated that pyroptosis can either inhibit or promote the development of malignant tumors, depending on the cell type (immune or cancer cells) and duration and severity of the process. This review summarizes the molecular mechanisms of pyroptosis, its relationship with malignancies, and focuses on current pyroptosis inducers and their significance in cancer treatment. The molecules involved in the pyroptosis signaling pathway could serve as therapeutic targets for the development of novel drugs for cancer therapy. In addition, we analyzed the potential of combining pyroptosis with conventional anticancer techniques as a promising strategy for cancer treatment.

[Mutational Signatures Analysis of Micropapillary Components and Exploration of ZNF469 Gene in Early-stage Lung Adenocarcinoma with Ground-glass Opacities].

BACKGROUND: In China, lung cancer remains the cancer with the highest incidence and mortality rate. Among early-stage lung adenocarcinomas (LUAD), the micropapillary (MPP) component is prevalent and typically exhibits high aggressiveness, significantly correlating with early metastasis, lymphatic infiltration, and reduced five-year survival rates. Therefore, the study is to explore the similarities and differences between MPP and non-micropapillary (non-MPP) components in malignant pulmonary nodules characterized by GGOs in early-stage LUAD, identify unique mutational features of the MPP component and analyze the relationship between the ZNF469 gene, a member of the zinc-finger protein family, and the prognosis of early-stage LUAD, as well as its correlation with immune infiltration. METHODS: A total of 31 malignant pulmonary nodules of LUAD were collected and dissected into paired MPP and non-MPP components using microdissection. Whole-exome sequencing (WES) was performed on the components of early-stage malignant pulmonary nodules. Mutational signatures analysis was conducted using R packages such as maftools, Nonnegative Matrix Factorization (NMF), and Sigminer to unveil the genomic mutational characteristics unique to MPP components in invasive LUAD compared to other tumor tissues. Furthermore, we explored the expression of the ZNF469 gene in LUAD using The Cancer Genome Atlas (TCGA) database to investigate its potential association with the prognosis. We also investigated gene interaction networks and signaling pathways related to ZNF469 in LUAD using the GeneMANIA database and conducted Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. Lastly, we analyzed the correlation between ZNF469 gene expression and levels of immune cell infiltration in LUAD using the TIMER and TISIDB databases. RESULTS: MPP components exhibited a higher number of genomic variations, particularly the 13th COSMIC (Catalogue of Somatic Mutations in Cancer) mutational signature characterized by the activity of the cytidine deaminase APOBEC family, which was unique to MPP components compared to non-MPP components in tumor tissues. This suggests the potential involvement of APOBEC in the progression of MPP components in early-stage LUAD. Additionally, MPP samples with high similarity to APOBEC signature displayed a higher tumor mutational burden (TMB), indicating that these patients may be more likely to benefit from immunotherapy. The expression of ZNF469 was significantly upregulated in LUAD compared to normal tissue, and was associated with poor prognosis in LUAD patients (P<0.05). Gene interaction network analysis and GO/KEGG enrichment analysis revealed that COL6A1, COL1A1, COL1A2, TGFB2, MMP2, COL8A2 and C2CD4C interacted with ZNF469 and were mainly involved in encoding collagen proteins and participating in the constitution of extracellular matrix. ZNF469 expression was positively correlated with immune cell infiltration in LUAD (P<0.05). CONCLUSIONS: The study has unveiled distinctive mutational signatures in the MPP components of early-stage invasive LUAD in the Asian population. Furthermore, we have identified that the elevated expression of mutated ZNF469 impacts the prognosis and immune infiltration in LUAD, suggesting its potential as a diagnostic and prognostic biomarker in LUAD.