Abundance Of Cells Research Articles

Possible protective effect of quercetin on lung injury induced by skeletal muscle ischemia reperfusion (IR) injury of adult male albino rats: Histological and biochemical study.

When a lower limb is injured, the most delicate organs that are at risk of harm are the lungs. Among the flavonoids, quercetin is a significant component that is found in apples and onions in the highest proportions. Numerous biological actions, including as anti-inflammatory, antioxidant, and anti-cancer properties, have been linked to quercetin. To investigate the impact of quercetin on lung injury induced by skeletal muscle ischemia reperfusion (IR) injury. Three equal groups of twenty-four adult rats were used: control, Ischemia-reperfusion (IR) group and IR group treated with quercetin. Rats in (IR) group were exposed to ischemia by ligation of femoral artery for 2h thenafter removal of the clamp, reperfusion was estabilished for another 24h. IR group treated with quercetin, rats were underwent hind limb IR as described in group II then were given quercetin that was administered at a dose of 20mg/kg intraperitoneally. Measurement of cytokinesin serum, MDAin tissue homogenate and VEGF in serumand tissue homogrnate in addition to mRNA expression level and detection of protein levelof bothsirtuin-1(SIRT1) and NF-κB were assessed at the end of experiment. Histological and immunohistochemical assessment of the lungs were also carried. IR group showed notable rise of inflammatory cytokines such as IL-1β, IL-6 and TNF-α in addition to high level of VEGF and MDA in IR group when compared to the IR group treated with quercetin. Also, gene expressionand protein level of SIRT1 were reduced while NF-κB mRNA expressionand protein level weresignificantly upregulated in IR group compared to IR group treated with quercetin. Histologically, IR group indicated marked histological alterations of lung tissue. Also, IR showed strong brownish cytoplasmic immunostaining for iNOS and abundance of Ki67-positive cells. These alterations were significantly reversed in IR group treated with quercetin. Biochemical and immunohistochemical findings of this study demonstrate that quercetin administration have protective effects against lung injury induced by lower limb IR.

The landscape in telomere related gene prognostic signature for survival and medication treatment effectiveness prediction in hepatocellular carcinoma

ObjectiveTelomeres, made of repetitive DNA sequences and shelterin complexes, which were found at the ends of chromosomes and had been extensively studied in cancer research. However, in hepatocellular carcinoma (HCC) was still relatively scarce. In this study, we investigated the correlation between telomerase-related genes (TRGs) and the prognosis and immunotherapy of HCC patients to enhance clinical outcomes.MethodsIn this work, TRGs were gathered using TelNet, while clinical information and gene expression data for HCC patients were retrieved from the Cancer Genome Atlas (TCGA) database. A risk prediction model based on TRGs was created using COX and Lasso regression analyses, with ROC curves used to assess prognostic efficacy. Univariate and multifactorial COX regression analyses were used to determine if the risk model had an independent impact on prognosis. Nomograms were created to enhance clinical usability, and calibration curves were used to assess predictive ability at various time points. The Tumor Immune Dysfunction and Exclusion (TIDE) score was used to analyze differences in immune infiltrating cells between risk groups. The study analyzed the relationship between risk ratings and drug treatment effectiveness using data from the CellMiner database. The hub gene was identified and its relationship to prognostic markers of HCC patients was examined. The expression of hub genes in immune cell subpopulations was also investigated by single-cell data.Results2093 TRGs were identified, with 949 showing significant differences in expression between HCC and paracancerous tissues. Seven risk genes were overexpressed in tumor tissues, leading to lower survival rates in high-risk patients. Risk model could independently predict the prognosis of HCC patients. Analysis of tumor immune infiltrating cells revealed significant differences in cell abundance between risk groups, with notable variations in immune subset enrichment between subgroups. Higher risk scores correlated with increased sensitivity to sorafenib, mitoxantrone, oxaliplatin, gemcitabine, and entinostat, while sensitivity decreased for vincristine, etc. CDCA8 was identified as a key gene in the Protein Interaction Network, while high expression associated with poorer overall survival, tumor proliferation and metastasis. The results of single-cell data analysis suggest that CDCA8 may promote the development of HCC by affecting T lymphocytes.ConclusionThe TRG-based risk model could predict HCC patient prognosis and closely linked to tumor immune environment, which could offer new possibilities for clinical treatment.

Myonuclear and satellite cell content of the vastus lateralis and soleus with70 days of simulated microgravity and the NASA SPRINT exercise program.

We previously observed a range of whole muscle and individual slow and fast myofiber size responses (mean: +4 to -24%) in quadriceps (vastus lateralis) and triceps surae (soleus) muscles of individuals undergoing 70 days of simulated microgravity with or without the NASA SPRINT exercise countermeasures program. The purpose of the current investigation was to further explore, in these same individuals, the content of myonuclei and satellite cells, both of which are key regulators of skeletal muscle mass. Individuals completed 6° head-down-tilt bedrest (BR, n=9), bedrest with resistance and aerobic exercise (BRE, n=9), or bedrest with resistance and aerobic exercise and low-dose testosterone (BRE+T, n=8). The number of myonuclei and satellite cells associated with each slow (myosin heavy chain (MHC) I) and fast (MHC IIa) myofiber in the vastus lateralis was not changed (P>0.05) pre- to post-bedrest within the BR, BRE, or BRE+T groups. Similarly, in the soleus the number of myonuclei associated with each slow and fast myofiber, and the number of satellite cells associated with each slow myofiber were not changed (P>0.05) pre- to post-bedrest within the BR, BRE, or BRE+T groups. It appears that even with relatively large perturbations in muscle mass over a few months of simulated microgravity, or with partially or completely effective exercise countermeasures, human skeletal muscle tightly regulates the abundance of myonuclei and satellite cells. Thus, exercise countermeasures efficacy for skeletal muscle atrophy appears to be independent of myonuclei and satellite cell abundance.

Proteolytic regulation of mitochondrial magnesium channel MRS2 by m-AAA protease and prohibitin complex.

Mitochondrial membrane phospholipid cardiolipin is essential for the stability of several inner mitochondrial membrane protein complexes. We recently showed that the abundance of mitochondrial magnesium channel MRS2 is reduced in models of Barth syndrome, an X-linked genetic disorder caused by a remodeling defect in cardiolipin. However, the mechanism underlying the reduced abundance of MRS2 in cardiolipin-depleted mitochondria remained unknown. In this study, we utilized yeast mutants of mitochondrial proteases to identify an evolutionarily conserved m-AAA protease, Yta10/Yta12, responsible for degrading Mrs2. The activity of m-AAA protease is regulated by the inner mitochondrial membrane scaffolding complex prohibitin, and consistent with this role, we find that Mrs2 turnover is increased in yeast prohibitin mutants. Importantly, we find that deleting Yta10 in cardiolipin-deficient yeast cells restores the steady-state levels of Mrs2 to the wild-type cells, and the knockdown of AFG3L2, a mammalian homolog of Yta12, increases the abundance of MRS2 in a murine muscle cell line. Thus, our work has identified the m-AAA protease/prohibitin complex as an evolutionarily conserved regulator of Mrs2 that can be targeted to restore Mrs2 abundance in cardiolipin-depleted cells.

BDSF Analogues Inhibit Quorum Sensing-Regulated Biofilm Production in Xylella fastidiosa

Xylella fastidiosa is an aerobic, Gram-negative bacterium that is responsible for many plant diseases. The bacterium is the causal agent of Pierce’s disease in grapes and is also responsible for citrus variegated chlorosis, peach phony disease, olive quick decline syndrome and leaf scorches of various species. The production of biofilm is intrinsically linked with persistence and transmission in X. fastidiosa. Biofilm formation is regulated by members of the Diffusible Signal Factor (DSF) quorum sensing signalling family which are comprised of a series of long chain cis-unsaturated fatty acids. This article describes the evaluation of a library of N-acyl sulfonamide bioisosteric analogues of BDSF, XfDSF1 and XfDSF2 for their ability to control biofilm production in X. fastidiosa. The compounds were screened against both the wild-type strain Temecula and an rpfF* mutant which can perceive but not produce XfDSF. Planktonic cell abundance was measured via OD600 while standard crystal violet assays were used to determine biofilm biomass. Several compounds were found to be effective biofilm inhibitors depending on the nature of the sulfonamide substituent. The findings reported here may provide future opportunities for biocontrol of this important plant pathogen.

RANKL treatment restores thymic function and improves T cell-mediated immune responses in aged mice.

Age-related thymic involution, leading to reduced T cell production, is one of the major causes of immunosenescence. This results in an increased susceptibility to cancers, infections, and autoimmunity and in reduced vaccine efficacy. Here, we identified that the receptor activator of nuclear factor κB (RANK)-RANK ligand (RANKL) axis in the thymus is altered during aging. Using a conditional transgenic mouse model, we demonstrated that endothelial cells depend on RANK signaling for their cellularity and functional maturation. Decreased RANKL availability during aging resulted in a decline in cellularity and function of both endothelial cells and thymic epithelial cells, contributing to thymic involution. We then found that, whereas RANKL neutralization in young mice mimicked thymic involution, exogenous RANKL treatment in aged mice restored thymic architecture as well as endothelial cell and epithelial cell abundance and functional properties. Consequently, RANKL improved T cell progenitor homing to the thymus and boosted T cell production. This cascade of events resulted in peripheral T cell renewal and effective antitumor and vaccine responses in aged mice. Furthermore, we conducted a proof-of-concept study that showed that RANKL stimulates endothelial cells and epithelial cells in human thymic organocultures. Overall, our findings suggest that targeting the RANK-RANKL axis through exogenous RANKL administration could represent a therapeutic strategy to rejuvenate thymic function and improve T cell immunity during aging.

Structural and functional parameters of the Black Sea phytoplankton during the summer bloom of the coccolithophore Emiliania huxleyi

The aim of the study was to examine the main primary production indicators, describe the controlling factors and identify the conditions for the weak bloom of Emiliania huxleyi in the Crimea coast of the Black Sea during June – July 2022. The surface chlorophyll a (Chl a) varied between 0.3 to 1.5mgm-3 and primary production (PP) within 12–174mgC m-3 day-1. The integrated concentration of Chl a in the euphotic layer was 4–29mgm-2, and that of PP - 240–835mgC m-3 day-1. On average, 49% of Chl a was located bellow the photosynthetic zone. The relationship between integral PP and the total Chl a, nitrogen (nitrates and ammonium), phosphates and silicates in the euphotic layer, analyzed by a multiple regression, showed that 70% of the PP variability was accounted for by the first three variables. While the significance of total Chl a was the highest, followed by phosphates, nitrogen had a negligible effect and that of silicates was not detected. In the surface layer (0–1m), the total phytoplankton biomass was co-dominated by dinoflagellates, the large cell diatom Pseudosolenia calcar-avis and the coccolithophore E. huxleyi. A weak bloom of E. huxleyi (cell abundance 1.0–1.8·106 cells L-1) was detected at 11 out of the 23 sampling stations. The relatively large thickness of the upper mixed layer (about 10m on average) and phosphorus deficiency were the main factors limiting the bloom of this coccolithophore.

Organic Matter Composition as a Driver of Soil Bacterial Responses to Pig Carcass Decomposition in a Canadian Continental Climate

AbstractOrganic by‐products are released into the surrounding soil during the terrestrial decomposition of animal remains. The affected area, known as the Cadaver Decomposition Island (CDI), can undergo biochemical changes that contribute to landscape heterogeneity. Soil bacteria are highly sensitive to labile inputs, but it is unknown how they respond to shifts in dissolved organic matter (DOM) quantity and quality resulting from animal decomposition. We aimed to evaluate the relationship between soil DOM composition and bacterial activity/function in CDIs under a Canadian temperate continental climate. This was studied in soils surrounding adult pig carcasses (n = 3) that were surface deposited within a mixed forested environment (Trois‐Rivières, Québec) in June 2019. Using fluorescence spectroscopy and dissolved organic carbon analyses, we detected a pulse of labile protein‐like DOM during the summer season (day 55). This was found to be an important driver of heightened soil bacterial respiration, cell abundance and potential carbohydrate metabolism. These bacterial disturbances persisted into the cooler autumn season (day 156) and led to the gradual transformation of labile DOM inputs into microbially sourced humic‐like compounds. By the spring (day 324), DOM quantities and bacterial measures almost recovered, but DOM quality remained distinct from surrounding vegetal humic signals. All observed effects were spatially constrained to the topsoil (A‐horizon) and within 20 cm laterally from the carcasses. These findings provide valuable insight into CDI organic matter cycling within a cold‐climate ecosystem. Repeated CDI studies will however be required to capture the changing dynamics resulting from increasing global temperatures.

Elucidating the molecular and immune interplay between head and neck squamous cell carcinoma and diffuse large B-cell lymphoma through bioinformatics and machine learning.

Head and neck squamous cell carcinoma (HNSCC) contributes significantly to global health challenges, presenting primarily in the oral cavity, pharynx, nasopharynx, and larynx. HNSCC has a high propensity for lymphatic metastasis. Diffuse large B-cell lymphoma (DLBCL), the most common subtype of non-Hodgkin lymphoma, exhibits significant heterogeneity and aggressive behavior, leading to high mortality rates. Epstein-Barr virus (EBV) is notably associated with DLBCL and certain types of HNSCC. The purpose of this study is to elucidate the molecular and immune interplay between HNSCC and DLBCL using bioinformatics and machine learning (ML) to identify shared biomarkers and potential therapeutic targets. Differentially expressed genes (DEGs) were identified using the "limma" package in R from the HNSCC dataset in The Cancer Genome Atlas (TCGA) database, and relevant modules were selected through weighted gene co-expression network analysis (WGCNA) from a DLBCL dataset in the Gene Expression Omnibus (GEO) database. Based on their intersection genes, functional enrichment analyses were conducted using Gene Ontology (GO), Disease Ontology, and Kyoto Encyclopedia of Genes and Genomes (KEGG) databases. Protein-protein interaction (PPI) networks and ML algorithms were employed to screen for biomarkers. The prognostic value of these biomarkers was evaluated using Kaplan-Meier (K-M) survival analysis and receiver operating characteristic (ROC) curve analyses. The Human Protein Atlas (HPA) database facilitated the examination of messenger RNA (mRNA) and protein expressions. Further analyses of mutations, immune infiltration, drug predictions, and pan-cancer impacts were performed. Additionally, single-cell RNA sequencing (scRNA-seq) data analysis at the cell type level was conducted to provide deeper insights into the tumor microenvironment. From 2,040 DEGs and 1,983 module-related genes, 85 shared genes were identified. PPI analysis with six algorithms proposed 21 prospective genes, followed ML examination yielded 16 candidates. Survival and ROC analyses pinpointed four hub genes-ACACB, MMP8, PAX5, and TNFAIP6-as significantly associated with patient outcomes, demonstrating high predictive capabilities. Evaluations of mutations and immune infiltration, coupled with drug prediction and a comprehensive cancer analysis, highlighted these biomarkers' roles in tumor immune response and treatment efficacy. The scRNA-seq data analysis revealed an increased abundance of fibroblasts, epithelial cells and mononuclear phagocyte system (MPs) in HNSCC tissues compared to lymphoid tissues. MMP8 showed higher expression in five cell types in HNSCC tissues, while TNFAIP6 and PAX5 exhibited higher expression in specific cell types. Leveraging bioinformatics and ML, this study identified four pivotal genes with significant diagnostic capabilities for DLBCL and HNSCC. The survival analysis corroborates their diagnostic accuracy, supporting the development of a diagnostic nomogram to assist in clinical decision-making.

An estrogen receptor signaling transcriptional program linked to immune evasion in human hormone receptor-positive breast cancer.

This study elucidates the immunosuppressive role of ER signaling in breast cancer, highlighting a complex interplay between cancer, stromal, and immune cells and reveals potential approaches to enhance immunogenicity in HR+ breast cancer. These findings offer crucial insights into immune evasion in breast cancer and identify strategies to enhance T cell abundance.

Identification and validation of diagnostic biomarkers and immune cell abundance characteristics in Staphylococcus aureus bloodstream infection by integrative bioinformatics analysis.

Staphylococcus aureus (S. aureus) is an opportunistic pathogen that could cause life-threatening bloodstream infections. The objective of this study was to identify potential diagnostic biomarkers of S. aureus bloodstream infection. Gene expression dataset GSE33341 was optimized as the discovery dataset, which contained samples from human and mice. GSE65088 dataset was utilized as a validation dataset. First, after overlapping the differentially expressed genes (DEGs) in S. aureus infection samples from GSE33341-human and GSE33341-mice samples, we detected 63 overlapping genes. Subsequently, the hub genes including DRAM1, PSTPIP2, and UPP1 were identified via three machine-learning algorithms: random forest, support vector machine-recursive feature elimination, and least absolute shrinkage and selection operator. Additionally, the receiver operating characteristic curve was leveraged to verify the efficacy of the hub genes. DRAM1 (AUC=1), PSTPIP2 (AUC=1), and UPP1 (AUC=1) were investigated and demonstrated significant expression differences (all P < 0.05) and diagnostic efficacy in the training and validation datasets. Furthermore, the relationship between the diagnostic markers and the abundance of immune cells was assessed using cell-type identification by estimating relative subsets of RNA transcripts (CIBERSORT). These three diagnostic indicators also correlated with multiple immune cells to varying degrees. The expression of DRAM1 was significantly positively correlated with B cell naive and mast cell activation, and negatively correlated with NK cells and CD4/CD8+ T cells. The expression of PSTPIP2 was significantly positively correlated with macrophage M0, macrophage M1, B cell naive, and dendritic cell activation, while the expression of PSTPIP2 was negatively correlated with NK cells and CD4/CD8+ T cells. Significant negative correlations between UPP1 expression and T cell CD4 memory rest and neutrophils were also observed. Finally, we established a mouse model of S. aureus bloodstream infection and collected the blood samples for RNA-Seq analysis and RT-qPCR experiments. The analysis results in RNA-Seq and RT-qPCR experiments further confirmed the significant expression differences (all P < 0.05) of these three genes. Overall, three candidate hub genes (DRAM1, PSTPIP2, and UPP1) were identified initially for S.aureus bloodstream infection diagnosis. Our study could provide potential diagnostic biomarkers for S. aureus bloodstream infection patients.

Experimental evolution at ecological scales allows linking of viral genotypes to specific host strains.

Viruses shape microbial community structure and activity through the control of population diversity and cell abundances. Identifying and monitoring the dynamics of specific virus-host pairs in nature is hampered by the limitations of culture-independent approaches such as metagenomics, which do not always provide strain-level resolution, and culture-based analyses, which eliminate the ecological background and in-situ interactions. Here, we have explored the interaction of a specific "autochthonous" host strain and its viruses within a natural community. Bacterium Salinibacter ruber strain M8 was spiked into its environment of isolation, a crystallizer pond from a coastal saltern, and the viral and cellular communities were monitored for one month using culture, metagenomics, and microscopy. Metagenome sequencing indicated that the M8 abundance decreased sharply after being added to the pond, likely due to forces other than viral predation. However, the presence of M8 selected for two species of a new viral genus, Phoenicisalinivirus, for which 120 strains were isolated. During this experiment, an assemblage of closely related viral genomic variants was replaced by a single population with the ability to infect M8, a scenario which was compatible with the selection of a genomic variant from the rare biosphere. Further analysis implicated a viral genomic region putatively coding for a tail fiber protein to be responsible for M8 specificity. Our results indicate that low abundance viral genotypes provide a viral seed bank that allows for a highly specialized virus-host response within a complex ecological background.

Disruption of mitochondrial electron transport impairs urinary concentration via AMPK-dependent suppression of aquaporin 2.

Urinary concentration is an energy-dependent process that minimizes body water loss by increasing aquaporin 2 (AQP2) expression in collecting duct (CD) principal cells. To investigate the role of mitochondrial (mt) ATP production in renal water clearance, we disrupted mt electron transport in CD cells by targeting ubiquinone (Q) binding protein QPC (UQCRQ), a subunit of mt complex III essential for oxidative phosphorylation. QPC-deficient mice produced less concentrated urine than controls, both at baseline and after type 2 vasopressin receptor stimulation with desmopressin. Impaired urinary concentration in QPC-deficient mice was associated with reduced total AQP2 protein levels in CD tubules, while AQP2 phosphorylation and membrane trafficking remained unaffected. In cultured inner medullary CD cells treated with mt complex III inhibitor antimycin A, the reduction in AQP2 abundance was associated with activation of 5' adenosine monophosphate-activated protein kinase (AMPK) and was reversed by treatment with AMPK inhibitor SBI-0206965. In summary, our studies demonstrated that the physiological regulation of AQP2 abundance in principal CD cells was dependent on mt electron transport. Furthermore, our data suggested that oxidative phosphorylation in CD cells was dispensable for maintaining water homeostasis under baseline conditions, but necessary for maximal stimulation of AQP2 expression and urinary concentration.

Sub-minimum inhibitory concentration of tetrakis(hydroxymethyl)phosphonium sulfate enhances biocorrosion of carbon steel by Pseudomonas aeruginosa

Biocide treatments are commonly employed to mitigate unwanted microbial activities in industrial water systems. This study illuminates the intriguing phenomenon wherein sub-minimum inhibitory concentration (sub-MIC) of tetrakis(hydroxymethyl)phosphonium sulfate (THPS), a frequently used biocide, stimulates the formation of biofilms by Pseudomonas aeruginosa, consequently intensifying the corrosion of carbon steel. Introducing 160 µg/ml THPS, constituting a sub-MIC level, into the culture medium resulted in a notable increase in biofilm thickness and corrosion rate, elevating them from 82 µm and 10 mpy to 97 µm and 18.7 mpy, respectively. Electrochemical impedance spectroscopy, Tafel polarization and linear polarization resistance measurements substantiated the extent of corrosion. Furthermore, the treated biofilm exhibited a heightened presence of extracellular polymeric substances, improved adherence to the metal surface, enhanced structural integrity, and an extended dispersal phase. Confocal laser scanning microscopy (CLSM) images revealed a greater abundance of viable sessile cells within the inner layers of the treated biofilm. These findings underscore the role of sub-MIC levels of biocides as a potential driving force for developing more corrosive biofilms on industrial materials, emphasizing the critical importance of precise biocide dosing.

Identification of Macrophage-Associated Novel Drug Targets in Atherosclerosis Based on Integrated Transcriptome Features.

This study explores the pathological mechanisms of atherosclerosis (AS), focusing on the role of macrophages in its formation and development, and potential therapeutic targets. The heterogeneity of the AS single-cell data set GSE131778 was analyzed using Seurat. Tissue sequencing data GSE28829 and GSE43292 were analyzed for immune cell abundance using CIBERSORT. Differential genes were identified, and WGCNA was used to create a coexpression network. Hub genes were identified using MCODE and CytoHubba and analyzed with GO and KEGG enrichment analysis, GSVA, and immune infiltration analysis. DrugBank identified potential drugs, and molecular docking verified drug binding to key targets. Key targets were experimentally validated. Nineteen cell clusters were identified in the GSE131778 data set, classified into ten cell types. Macrophages in AS and normal tissues were identified based on cell abundance. CIBERSORT showed a significant increase in cell cluster 9 in AS samples. Thirty-two hub genes, including CD86, LILRB2, and IRF8, were validated. GO and KEGG analyses indicated Hub genes primarily affect immune functions. GSVA identified 29 significantly increased pathways in AS samples. Immune infiltration analysis revealed a positive correlation between IRF8, CD86, and LILRB2 expression and macrophage content. Molecular docking suggested CD86 as a potential drug target for AS. qRT-PCR confirmed increased IRF8 and CD86 expression. CD86, LILRB2, and IRF8 are highly expressed in foam cell samples, with CD86 forming hydrogen bonds with several AS drugs, indicating CD86 as a promising target for AS treatment.

Enteric bacterial infection stimulates remodelling of bile metabolites to promote intestinal homeostasis

The liver makes bile, an aqueous solution critical for fat absorption, which is secreted into the duodenum. Despite extensive studies on bile salts, other components of bile are less well characterized. Here we used global metabolomic analysis on bile from specific-pathogen-free, germ-free, Citrobacter rodentium-infected or Listeria monocytogenes-infected mice and identified a metabolome of 812 metabolites that were altered by both microbiota and enteric infection. Hepatic transcriptomics identified enteric-infection-triggered pathways that probably underlie bile remodelling. Enteric infection increased levels of four dicarboxylates in bile, including itaconate. Analysis of Acod1−/− mice indicated that increased itaconate also increased tuft cell abundance, altered microbiota composition and function as detected by metagenomic analysis, and modulated host defence, leading to reduced Vibrio cholerae colonization. Our data suggest that enteric-infection-associated signals are relayed between the intestine and liver and induce transcriptional programmes that shape the bile metabolome, modifying the immunomodulatory and host defence functions of bile.

Abstract C011: The impact of reproductive factors on breast tumor and normal-adjacent tissue immune profile from menarche to menopause

Abstract Background: Reproductive factors and sex hormones are tightly linked to systemic immunity. However, no studies have examined whether reproductive factors and exogenous hormone use modulate the immune microenvironment of breast tissue. Methods: We prospectively evaluated the associations of reproductive factors (age at menarche, parity, age at first birth, age at menopause, and menopausal status) and exogenous hormone use (oral contraceptives, and menopausal hormone therapy (MHT)) with breast tumor and normal-adjacent tissue immune cell markers among 935 breast cancer cases in the Nurses’ Health Studies. We deconvoluted immune cell abundance using CIBERSORTx and derived gene expression signatures of markers for immune checkpoint (PD1, PDL1, and CTLA4), co-regulatory signal and antigen presentation (MHC class I/ II and T cell receptor) and mammary cytokine signaling (IFN gamma, IL2, IL4, IL12, IL13, TGF beta). Linear regression was used with adjustment for potential confounders. Results: Majority of participants had estrogen receptor (ER)-positive breast cancer (81%) and were post-menopausal at diagnosis (72%). Compared to tumors from pre-menopausal women, tumors from post-menopausal women had higher signature scores for tumor pro-inflammatory cytokine signaling (IFN gamma, IL2, IL4, IL12, IL13, TGF beta) and antigen presentation (FDR≤0.05). Several of the inflammatory cytokine signatures showed modest inverse relations with signatures of immune checkpoint markers (ρ=-0.3 to -0.4). Women who reported current use of estrogen only MHT had higher expression of CTLA4 in ER-positive breast tumors. For normal-adjacent tissues of ER-positive tumors, parity was associated with higher CD8+ T cell abundance, higher PDL1 expression and lower cytokine signaling in normal-adjacent tissues at p≤0.05; while breastfeeding was associated with lower abundance of CD8+ T cell and higher expression of cytokine signaling in normal-adjacent tissues of ER-negative tumors (p≤0.05). None of the associations in normal-adjacent tissues met FDR significance. The associations between other reproductive factors and immune cell profiles were in general weak. Conclusions: Our study suggests pre-diagnostic reproductive factors may influence breast tumor immune profiles. Future studies are needed to validate these results. Citation Format: Cheng Peng, Yuxi Liu, Yujing Heng, Clara Bodelon, Daniel Stover, Wendy Y. Chen, Michelle D. Holmes, A. Heather Eliassen, Peter Kraft, Rulla M. Tamimi. The impact of reproductive factors on breast tumor and normal-adjacent tissue immune profile from menarche to menopause [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr C011.

Single-cell transcriptomics link gene expression signatures to clinicopathological features of gonadotroph and lactotroph PitNET

BackgroundPituitary neuroendocrine tumors (PitNET) are among the most common intracranial tumors. Despite a frequent benign course, aggressive behavior can occur. Tumor behavior is known to be under the influence of the tumor microenvironment (TME). However, the relationship between TME cells and aggressive tumor behavior has not been adequately explored in PitNET.MethodsWe performed differential expression analysis as well as gene expression program identification based on single-cell RNA sequencing to comparatively characterize the transcriptome of seven gonadotroph and three lactotroph PitNET and correlate it with clinical features using bulk RNA-seq data from an independent cohort of 134 PitNET. Tumor immune infiltration was quantified via immunostaining on tissue sections of gonadotroph and lactotroph PitNET.ResultsIn lactotroph PitNET, we detect a highly proliferative gene profile with significantly increased expression levels in aggressively growing tumors within bulk RNA-seq data of an independent cohort of 134 PitNET samples. We also report high intratumoral heterogeneity in gonadotroph PitNET (GoPN) and lactotroph PitNET (LaPN) and identify signatures of epithelial, endocrine, and immunological gene networks in both subtypes. A comparison of their TME composition shows enrichment of SPP1+ macrophages and CD4+ T cells in GoPN, as well as enrichment of CD4/CD8 double-negative T cells (DN) and natural killer cells (NK) in LaPN. Also notable is the presence of proliferative lymphocytes, the occurrence of which positively correlates with more aggressive tumor behavior in the bulk RNA-seq cohort. However, increased CD8+ T and NK cell abundances correlate significantly with reduced aggressiveness indicating potential anti-tumoral effects.ConclusionsOur study expands the knowledge of the differences in cellular composition of gonadotroph and lactotroph PitNET subtypes. It lays the foundation for further studies on the influence of lymphoid cells on the variable aggressive behavior of PitNET. Regarding the treatment of drug-resistant lactotroph PitNET, proliferative lymphocytes, CD8+ T, and NK cells could represent potentially valuable targets for developing new cancer immunotherapies.

Peripheral immune cell abundance differences link blood mitochondrial DNA copy number and Parkinson’s disease

Mitochondrial dysfunction plays an important role in Parkinson’s disease (PD), with mitochondrial DNA copy number (mtDNA-CN) emerging as a potential marker for mitochondrial health. We investigated the links between blood mtDNA-CN and PD severity and risk using the Accelerating Medicines Partnership program for Parkinson’s Disease dataset, replicating our results in the UK Biobank. Our findings reveal that reduced blood mtDNA-CN levels are associated with heightened PD risk and increased severity of motor symptoms and olfactory dysfunction. We estimated blood cell composition using complete blood cell profile when available or RNA-sequencing data as a surrogate. After adjusting for blood cell composition, the associations between mtDNA-CN and PD risk and clinical symptoms became non-significant. Bidirectional Mendelian randomization analysis also found no evidence of a direct causal relationship between blood mtDNA-CN and PD susceptibility. Hence peripheral inflammatory immune responses rather than mitochondrial dysfunction underpin these previously identified associations in PD.

Seasonality and interannual variability of an arctic marine time series, IsA

The Arctic is warming twice as fast as anywhere else on the planet, in the European Arctic mainly driven by exalted Atlantic Water inflow. Microbial eukaryotes are diverse and essential to the functioning of marine ecosystems, thus environmental perturbations altering their communities influence the entire ecosystem. To study seasonal and interannual variation and the potential effects of Atlantification, a long-term marine time series has been established in Isfjorden-Adventfjorden (IsA), West Spitsbergen. We here present three years of high-resolution data including hydrography, nutrients, photosynthetic biomass, flow cytometry and community composition of microbial eukaryotes (0.45–10μm, based on Illumina metabarcoding of 18S rDNA and rRNA). The timing, magnitude and species composition of the spring bloom varied interannually, with the more Atlantic spring 2014 being distinctly different from the two other years. A strong recurring seasonal pattern was evident in biodiversity, cell abundances and community composition. Winter communities were characterized by high alpha diversity and very low cell numbers with a dominance of heterotrophic and parasitic taxa. Despite large intra- and interannual differences in communities during the productive time of the year, winter communities were always highly similar, suggesting that the polar night represents a strong environmental forcing that resets the microbial communities.