Early Alterations Research Articles

Right Ventricle and Autoimmune Diseases.

Autoimmune diseases can express pathologies in specific organs (e.g. thyroid, pancreas, skin) or generate systemic pathologies (generalized lupus erythematosus, rheumatoid arthritis, systemic sclerosis), the latter usually present systemic inflammatory phenomena. Some studies have reported alterations in right ventricular contractility in patients with rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, and juvenile idiopathic arthritis, which may contribute to the known outcome of increased cardiovascular risk. However, there is not much information available on the causes that generate these alterations, the most likely being small vessel damage and fibrosis due to subclinical inflammation.1-5 In this sense, the disease in which the alterations of the right ventricle have been more studied is systemic sclerosis, specifically at the changes induced due to pulmonary arterial hypertension, this being one of the main causes of death in this group of patients after the significant decrease in mortality associated with the sclerodermic renal crisis with the treatment of angiotensin-converting enzyme inhibitors. In this review, we will focus on explaining the structural and functional changes that occur in the right ventricle of patients with systemic sclerosis, from early alterations to late complications. In this context, it is necessary to distinguish between right heart alterations that occur in patients with systemic sclerosis and pulmonary arterial hypertension and those that occur without pulmonary arterial hypertension and that can be attributed to other causes such as microvascular damage or myocardial fibrosis.

The Early Pathogenesis of Diabetic Retinopathy and Its Attenuation by Sodium-Glucose Transporter 2 Inhibitors.

The early pathogenetic mechanism of diabetic retinopathy (DR) and its treatment remain unclear. Therefore, we investigated the early pathogenic alterations in DR using streptozotocin-induced diabetic mice and the protective effect of sodium-glucose cotransporter 2 (SGLT2) inhibitors against these alterations. Retinal vascular leakage was assessed by dextran fluorescence angiography. Retinal thickness and vascular leakage were increased 2 and 4 weeks after onset of diabetes, respectively. Immunostaining showed that morphological change of microglia (amoeboid form) was observed at 2 weeks. Subsequently, increased angiopoietin-2 expression, simultaneous loss of pericytes and endothelial cells, decreased vessel density, retinal hypoxia, and increased vascular endothelial growth factor (VEGF)-A/VEGF receptor system occurred at 4 weeks. SGLT2 inhibitors (luseogliflozin and ipragliflozin) had a significant protective effect on retinal vascular leakage and retinal thickness at a low dose that did not show glucose-lowering effects. Furthermore, both inhibitors at this dose attenuated microglia morphological changes and these early pathogenic alterations in DR. In vitro study, both inhibitors attenuated the lipopolysaccharide-induced activation of primary microglia, along with morphological changes toward an inactive form, suggesting the direct inhibitory effect of SGLT2 inhibitors on microglia. In summary, SGLT2i may directly prevent early pathogenic mechanisms, thereby potentially playing a role in preventing DR.

Exploring the Pathophysiology of ATP-Dependent Potassium Channels in Insulin Resistance.

Ionic channels are present in eucaryotic plasma and intracellular membranes. They coordinate and control several functions. Potassium channels belong to the most diverse family of ionic channels that includes ATP-dependent potassium (KATP) channels in the potassium rectifier channel subfamily. These channels were initially described in heart muscle and then in other tissues such as pancreatic, skeletal muscle, brain, and vascular and non-vascular smooth muscle tissues. In pancreatic beta cells, KATP channels are primarily responsible for maintaining the membrane potential and for depolarization-mediated insulin release, and their decreased density and activity may be related to insulin resistance. KATP channels' relationship with insulin resistance is beginning to be explored in extra-pancreatic beta tissues like the skeletal muscle, where KATP channels are involved in insulin-dependent glucose recapture and their activation may lead to insulin resistance. In adipose tissues, KATP channels containing Kir6.2 protein subunits could be related to the increase in free fatty acids and insulin resistance; therefore, pathological processes that promote prolonged adipocyte KATP channel inhibition might lead to obesity due to insulin resistance. In the central nervous system, KATP channel activation can regulate peripheric glycemia and lead to brain insulin resistance, an early peripheral alteration that can lead to the development of pathologies such as obesity and Type 2 Diabetes Mellitus (T2DM). In this review, we aim to discuss the characteristics of KATP channels, their relationship with clinical disorders, and their mechanisms and potential associations with peripheral and central insulin resistance.

Diffusion tensor imaging reveals subclinical alterations in muscles of patients with becker muscular dystrophy.

Becker muscular dystrophy (BMD) is a relatively less investigated neuromuscular disease, partially overlapping the phenotype of Duchenne dystrophy (DMD). Physiopathological and anatomical patterns are still not comprehensively known, despite recent effort in the search of early biomarkers. Aim of this study was to selectively compare normal appearing muscles of BMD with healthy controls. Among a pool of 40 BMD patients and 20 healthy controls, Sartorius and gracilis muscles were selected on the basis of a blinded clinical quantitative/qualitative evaluation, if classified as normal appearing (0 or 1 on Mercuri scale) and subsequently segmented on diffusion tensor MRI scans with a tractographic approach. Diffusion derived parameters were extracted. Non-parametric testing revealed significant differences between normal and normal appearing BMD diffusion derived parameters in both muscles, the difference being more evident in sartorius. Bonferroni-corrected p-values (<0.05) of Mann-Whitney test could discriminate between BMD and controls for standard deviation of all diffusion parameters (mean diffusivity, fractional anisotropy, axial and radial diffusivity) in both sartorius and gracilis, while in sartorius the significant difference was found also in the average values of the same parameters (with exception of RD). This method proved to be able to identify possible early or subclinical microstructural alterations in BMD muscles. This is to our knowledge the first imaging study to provide evidence of such microstructural alterations in muscles rated as normal in a conventional imaging-based assessment.

Early Alterations in Inner-Retina Neural and Glial Saturated Responses in Lens-Induced Myopia.

Myopic marmosets are known to exhibit significant inner retinal thinning compared to age-matched controls. The purpose of this study was to assess inner retinal activity in marmosets with lens-induced myopia compared to age-matched controls and evaluate its relationship with induced changes in refractive state and eye growth. Cycloplegic refractive error (Rx), vitreous chamber depth (VCD), and photopic full-field electroretinogram were measured in 14 marmosets treated binocularly with negative contact lenses compared to 9 untreated controls at different stages throughout the experimental period (from 74 to 369days of age). The implicit times of the a-, b-, d-, and photopic negative response (PhNR) waves, as well as the saturated amplitude (Vmax), semi-saturation constant (K), and slope (n) estimated from intensity-response functions fitted with Naka-Rushton equations were analyzed. Compared to controls, treated marmosets exhibited attenuated b-, d-, and PhNR waves Vmax amplitudes 7 to 14days into treatment before compensatory changes in refraction and eye growth occurred. At later time points, when treated marmosets had developed axial myopia, the amplitudes and implicit times of the b-, d-, and PhNR waves were similar between groups. In controls, the PhNR wave saturated amplitude increased as the b + d-wave Vmax increased. This trend was absent in treated marmosets. Marmosets induced with negative defocus exhibit early alterations in inner retinal saturated amplitudes compared to controls, prior to the development of compensatory myopia. These early ERG changes are independent of refraction and eye size and may reflect early changes in bipolar, ganglion, amacrine, or glial cell physiology prior to myopia development. The early changes in retinal function identified in the negative lens-treated marmosets may serve as clinical biomarkers to help identify children at risk of developing myopia.

Fixel-based analysis reveals tau-related white matter changes in early stages of Alzheimer's disease.

Several studies have shown white matter (WM) abnormalities in Alzheimer's disease (AD) using diffusion tensor imaging (DTI). Nonetheless, robust characterization of WM changes has been challenging due to the methodological limitations of DTI. We applied fixel-based analyses (FBA) to examine microscopic differences in fiber density (FD) and macroscopic changes in fiber cross-section (FC) in early stages of AD (N = 393, 212 females). FBA was also compared with DTI, free-water corrected (FW)-DTI and diffusion kurtosis imaging (DKI). We further investigated the correlation of FBA and tensor-derived metrics with AD pathology and cognition. FBA metrics were decreased in the entire cingulum bundle, uncinate fasciculus and anterior thalamic radiations in Aβ-positive patients with mild cognitive impairment compared to control groups. Metrics derived from DKI, and FW-DTI showed similar alterations whereas WM degeneration detected by DTI was more widespread. Tau-PET uptake in medial temporal regions was only correlated with reduced FC mainly in the parahippocampal cingulum in Aβ-positive individuals. This tau-related WM alteration was also associated with impaired memory. Despite the spatially extensive between-group differences in DTI-metrics, the link between WM and tau aggregation was only revealed using FBA metrics implying high sensitivity but low specificity of DTI-based measures in identifying subtle tau-related WM degeneration. No relationship was found between amyloid load and any diffusion-MRI measures. Our results indicate that early tau-related WM alterations in AD are due to macrostructural changes specifically captured by FBA metrics. Thus, future studies assessing the effects of AD pathology in WM tracts should consider using FBA metrics.Significance Statement Diffusion tensor imaging (DTI) has been widely used to study white matter (WM) integrity in Alzheimer's disease (AD). However, the methodological shortcomings of DTI limit an accurate biological interpretation. We used fixel-based analysis (FBA) to assess fiber-specific WM degeneration and its correlation with the underlying pathology and cognitive symptoms in early AD. Our results revealed that elevated tau- but not Aβ-PET uptake in the medial temporal structures was correlated with atrophy of the parahippocampal portion of the cingulum bundle. The tau-related damage in this WM bundle was further linked to memory deficits. Importantly, the tau-WM correlation was not detected by tensor-derived measures. These findings suggest that FBA metrics may serve as a biomarker for early detection of tau pathology in AD.

The following article for this Special Issue was previously published and can be found in its respective issue online: "Detection of early Alzheimer's disease-like molecular alterations in a mouse model expressing human ApoE4".

Detection of early Alzheimer's disease-like molecular alterations in a mouse model expressing human ApoE4 (Published in JNC 166.3 issue) https://onlinelibrary.wiley.com/doi/10.1111/jnc.15904.

Native-state proteomics of Parvalbumin interneurons identifies unique molecular signatures and vulnerabilities to early Alzheimer’s pathology

Dysfunction in fast-spiking parvalbumin interneurons (PV-INs) may represent an early pathophysiological perturbation in Alzheimer’s Disease (AD). Defining early proteomic alterations in PV-INs can provide key biological and translationally-relevant insights. We used cell-type-specific in-vivo biotinylation of proteins (CIBOP) coupled with mass spectrometry to obtain native-state PV-IN proteomes. PV-IN proteomic signatures include high metabolic and translational activity, with over-representation of AD-risk and cognitive resilience-related proteins. In bulk proteomes, PV-IN proteins were associated with cognitive decline in humans, and with progressive neuropathology in humans and the 5xFAD mouse model of Aβ pathology. PV-IN CIBOP in early stages of Aβ pathology revealed signatures of increased mitochondria and metabolism, synaptic and cytoskeletal disruption and decreased mTOR signaling, not apparent in whole-brain proteomes. Furthermore, we demonstrated pre-synaptic defects in PV-to-excitatory neurotransmission, validating our proteomic findings. Overall, in this study we present native-state proteomes of PV-INs, revealing molecular insights into their unique roles in cognitive resiliency and AD pathogenesis.

Dynamic microglia alterations associate with hippocampal network impairments: A turning point in amyloid pathology progression

Alzheimer's disease is a progressive neurological disorder causing memory loss and cognitive decline. The underlying causes of cognitive deterioration and neurodegeneration remain unclear, leading to a lack of effective strategies to prevent dementia. Recent evidence highlights the role of neuroinflammation, particularly involving microglia, in Alzheimer's disease onset and progression. Characterizing the initial phase of Alzheimer's disease can lead to the discovery of new biomarkers and therapeutic targets, facilitating timely interventions for effective treatments.We used the AppNL-G-F knock-in mouse model, which resembles the amyloid pathology and neuroinflammatory characteristics of Alzheimer’s disease, to investigate the transition from a pre-plaque to an early plaque stage with a combined functional and molecular approach.Our experiments show a progressive decrease in the power of cognition-relevant hippocampal gamma oscillations during the early stage of amyloid pathology, together with a modification of fast-spiking interneuron intrinsic properties and postsynaptic input. Consistently, transcriptomic analyses revealed that these effects are accompanied by changes in synaptic function-associated pathways. Concurrently, homeostasis- and inflammatory-related microglia signature genes were downregulated. Moreover, we found a decrease in Iba1-positive microglia in the hippocampus that correlates with plaque aggregation and neuronal dysfunction. Collectively, these findings support the hypothesis that microglia play a protective role during the early stages of amyloid pathology by preventing plaque aggregation, supporting neuronal homeostasis, and overall preserving the oscillatory network’s functionality.These results suggest that the early alteration of microglia dynamics could be a pivotal event in the progression of Alzheimer's disease, potentially triggering plaque deposition, impairment of fast-spiking interneurons, and the breakdown of the oscillatory circuitry in the hippocampus.

Abstract 446: Integrated spatial transcriptomics and lipidomics analyses of intraductal papillary mucinous neoplasm identifies enrichment of long chain sulfatide as an early metabolic alteration

Abstract Purpose: To define the metabolic alterations associated with malignant progression of intraductal papillary mucinous neoplasm (IPMN). Experimental Procedures: Matrix-assisted laser desorption/ionization (MALDI)-mass spectrometry (MS) was conducted for spatial characterization of lipid profiles on frozen tissue sections from resected human IPMN patients. The specimen set consisted of either low-grade dysplasia (LG) (n=15), high-grade (HG) dysplasia (n=4), or with an associated pancreatic ductal adenocarcinoma (PDAC) (n=4) as well as 15 PDAC tissues. Utilizing serial sections to the same human IPMN cases analyzed with MALDI-MS imaging, we used the Visium Spatial Gene Expression technology platform to characterize the spatiomolecular underpinnings of LG and HG IPMN. H&amp;E images of the same tissue section used for the Visium workflow, were used to annotate the spots in the dataset covering the epithelial lining of the IPMN lesions (“epilesional” areas) and the spots covering the adjacent microenvironment surrounding the lesion (“perilesiopecific” area). Findings were compared with lipidomic analyses of cystic fluid from 89 IPMN patients. The anti-cancer efficacy of UGT8-IN-1, a selective small molecule inhibitor of ceramide galactosyltransferase (CGT, also known as UGT8), was assessed in vitro and in mutant Kras;Gnas allografts. Results: MALDI/MS-based spatial imaging of human resected IPMN tissues and pancreata from a mutant Kras;Gnas mouse model of IPMN revealed long-chain hydroxylated sulfatides, particularly the C24:0(OH) and C24:1(OH) species, to be selectively enriched in the IPMN and PDAC neoplastic epithelium. Visium spatial transcriptomics data confirmed that the cognate transcripts engaged in sulfatide biosynthesis, including UGT8, Gal3St1, and FA2H, were co-localized with areas of sulfatide enrichment. Lipidomic analyses of cystic fluid from 89 patients with IPMN identified several sulfatide species to be significantly elevated in patients with IPMN/PDAC compared to those with low-grade IPMN. Inhibition of sulfatide metabolism via UGT8-IN-1 reduced viability of Kras;Gnas murine cell lines in vitro and attenuated tumor growth in an allograft IPMN model. UGT8-IN-1 treatment resulted in reduced levels of several sulfatide species, accompanied by a concomitant increase in a subset of quantified sulfatides precursor ceramides, accumulation of mitochondrial mass and reactive oxygen species and time-dependent increases in autophagy/mitophagy markers p62/SQSTM1 and LC-3B, suggesting impaired mitophagy. Conclusion: Enhanced sulfatide metabolism is an early alteration in cystic pre-cancerous lesions of the pancreas that persists through invasive neoplasia. Targeting sulfatide biosynthesis might represent an actionable vulnerability for cancer interception. Citation Format: Yihui Chen, Marta Sans, Fredrik Thege, Rongzhang Dou, Jimin Min, Michele Yip-Schneider, Jianjun Zhang, Ranran Wu, Ehsan Irajizad, Yuki Makino, Kimal Rajapakshe, Mark Hurd, Ricardo León-Letelier, Jody Vykoukal, Jennifer Dennison, Kim-Anh Do, Robert Wolff, Paola Guerrero, Michael Kim, Max Schmidt, Anirban Maitra, Samir Hanash, Johannes Fahrmann. Integrated spatial transcriptomics and lipidomics analyses of intraductal papillary mucinous neoplasm identifies enrichment of long chain sulfatide as an early metabolic alteration [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 446.

Abstract 7039: Leveraging single cell RNA-seq for uncovering immune landscape of hepatocellular carcinoma

Abstract The immune cell types as well as tumor microenvironment (TME) status may influence prognosis, metastasis, tumor progression, and clinical response to immunotherapies for cancer. Hepatocellular carcinoma (HCC) is a typical highly heterogeneous solid tumor with high morbidity and mortality worldwide, especially in China, however, the immune microenvironment of HCC, especially which caused by cancerogenic substance has not been clarified so far. In this study, we employed single-cell RNA sequencing (scRNA-seq) on diethylnitrosamine (DEN)-induced mouse HCC model to dissect the immune cell dynamics during tumorigenesis. Our findings reveal distinct immune profiles in both precancerous and cancerous lesions, indicating early tumor-associated immunological alterations. Notably, specific T and B cell subpopulations are preferentially enriched in the HCC TME. Furthermore, we identified a subpopulation of naïve B cells with high CD83 expression, correlating with improved prognosis in human HCC. These signature genes were validated in The Cancer Genome Atlas (TCGA) HCC RNA-seq dataset. Moreover, cell interaction analysis revealed that subpopulations of B cells in both mouse and human samples are activated and may potentially contribute to oncogenic processes. In summary, our study provides insights into the dynamic immune microenvironment and cellular networks in HCC pathogenesis, with a specific emphasis on naïve B cells. These findings emphasize the significance of targeting TME in HCC patients to prevent HCC pathological progression, which may give a new perspective on the therapeutics for the HCC. Citation Format: Jian He. Leveraging single cell RNA-seq for uncovering immune landscape of hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7039.

Abstract 6235: Clinical and phenotypic consequences of HLA mediated antigen presentation deficiency in pancreatic adenocarcinoma at bulk and single-cell resolution

Abstract Introduction: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal neoplasm of the pancreas characterized by a low survival rate and limited treatment options. Despite the success of immunotherapy in various cancer types, its efficacy in PDAC remains low. The underlying reasons for this discrepancy are not fully understood, despite PDAC exhibiting a moderate mutation burden. One possible determinant could be the loss of heterozygosity (LOH) at the human leukocyte antigen (HLA) loci, resulting in compromised antigen presentation. In this work, we aim to identify and validate HLA LOH events in two independent cohorts to gain insights into both their prevalence and clinical and phenotypic impact on PDAC. Methods: We applied LOHHLA, a specialized pipeline to identify HLA LOH events from paired whole genome sequencing to two independent cohorts comprising over 650 patients. We contextualized these results with the paired transcriptome-wide gene expression data and immunohistochemistry stains. In addition, we developed a machine learning classifier to predict HLA LOH from transcriptomic data. We transfer this classifier to single cell RNA sequencing data to identify the impact of (subclonal) HLA LOH on the tumor microenvironment. Results: HLA LOH events occur in approximately 30% of PDAC patients, with about 50% of these deletions being focal deletions. We find evidence that focal but not non-focal LOH is a driver of immune escape. Overall, we find that HLA LOH events are early genetic alterations and observe a significant association between HLA LOH and the Basal PDAC expression subtype. In addition, we find that HLA expression is the most important determinant of lymphocyte infiltration followed by an intact HLA locus. Moreover, our transcriptomic classifier allowed us to accurately identify HLA LOH events from RNA sequencing data, which we successfully validated in an independent cohort. Finally, we applied this classifier to single cell sequencing data and identified phenotypic differences in multiple compartments of the tumor microenvironment between samples with intact HLA and HLA LOH. Conclusions: In conclusion, our study provides the most in depth characterization of the consequences of altered antigen presentation in PDAC to date. We have demonstrated that HLA LOH occurs in a substantial proportion of patients. Overall, these findings contribute to a better understanding of the immune landscape in PDAC and may have implications for the development of immunotherapeutic strategies tailored to this challenging cancer type. Citation Format: Michael J. Geuenich, Barbara Gruenwald, Grainne O'Kane, Chengxin Yu, Tan Tiak Ju, Amy Zhang, Oumaima Hamza, Gun Ho Jang, Faiyaz Notta, Steven Gallinger, Kieran R. Campbell. Clinical and phenotypic consequences of HLA mediated antigen presentation deficiency in pancreatic adenocarcinoma at bulk and single-cell resolution [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6235.

Abstract 4259: A novel human model of lung squamous cell carcinoma to deconvolve the cell-intrinsic effects of key dysregulated pathways

Abstract Tractable, patient relevant models are needed to investigate the essential components of normal cell transformation. We developed a unique in vitro model of early lung squamous cell carcinoma (LUSC) genetic alterations and driver pathway dysregulation using genetically modified primary human bronchial basal cells (hBCs) from three independent donors. The co-operation of ubiquitous and early LUSC alterations (TP53 and CDKN2A loss) and commonly deregulated pathways including squamous differentiation (SOX2), PI3K signaling (PTEN) and the oxidative stress response (KEAP1) was investigated using a combinatorial approach, culminating in eight unique hBC mutants harboring cumulative pathway alterations in a TP53-/-/CDKN2A-/- background. Phenotypes indicative of mutant hBC transformation were investigated using proliferation assays, organotypic cultures and anchorage independent growth assays. Organotypic cultures revealed LUSC pathway alterations to drive dramatic changes in airway histology, ranging from a normal epithelium to severe dysplasia. Furthermore, these analyses confirmed the role of SOX2-overexpression in initiating transformation by inducing squamous cell commitment and anchorage independent growth. We also identified a co-operation of SOX2-overexpression with the oxidative stress response and PI3K pathways to drive more advanced lesions in-vivo and in-vitro. Importantly, we were able to map changes in the expression of immunomodulatory factors with the pathway dysregulation. We demonstrated that this strategy constitute an alternative and patient-relevant system to model LUSC and identify genotype-phenotype correlations of clinical relevance. Citation Format: Julia Ogden, Robert Sellers, Anthony Oojageer, Sudhakar Sahoo, Anshuman Chaturvedi, Carlos Lopez-Garcia. A novel human model of lung squamous cell carcinoma to deconvolve the cell-intrinsic effects of key dysregulated pathways [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4259.

Oestradiol and osteoclast differentiation: Effects on p53 and mitochondrial metabolism.

Oestrogen deficiency increases bone resorption, contributing to osteoporosis development. Yet, the mechanisms mediating the effects of oestrogen on osteoclasts remain unclear. This study aimed to elucidate the early metabolic alteration induced by RANKL, the essential cytokine in osteoclastogenesis and 17-beta-oestradiol (E2) on osteoclast progenitor cells, using RAW 264.7 macrophage cell line and primary bone marrow-derived macrophages as biological models. This research demonstrated that, in osteoclast precursors, RANKL stimulates complex I activity, oxidative phosphorylation (OXPHOS) and mitochondria-derived ATP production as early as 3 h of exposure. This effect on mitochondrial bioenergetics is associated with an increased capacity to oxidize TCA cycle substrates, fatty acids and amino acids. E2 inhibited all effects of RANKL on mitochondria metabolism. In the presence of RANKL, E2 also decreased cell number and stimulated the mitochondrial-mediated apoptotic pathway, detected as early as 3 h. Further, the pro-apoptotic effects of E2 during osteoclast differentiation were associated with an accumulation of p392S-p53 in mitochondria. These findings elucidate the early effects of RANKL on osteoclast progenitor metabolism and suggest novel p53-mediated mechanisms that contribute to postmenopausal osteoporosis.

Abstract 1247: PPARsing epigenetic memory in intestinal stem cells: High-fat diet and oncogenic susceptibility

Abstract Diet has a profound impact on health and susceptibility to cancer. Adaptation to a Western diet is strongly associated with increased colorectal cancer (CRC) and obesity prevalence. This study demonstrates the epigenetic changes in intestinal stem cells (ISCs) induced by a pro-obesity high-fat Western diet (HFD) and the heightened risk of oncogenic transformation. A HFD induces a phenotype characterized by increased ISC frequency, proliferation, regenerative capacity, and ability to initiate adenomas. We hypothesized that a HFD generates lasting epigenetic alterations in ISCs thereby enhancing oncogenic susceptibility. We evaluated the chromatin landscape of intestinal stem cells (ISCs) and the reversibility of the epigenetic changes. Mice carrying a fluorescent reporter of the ISC marker Lgr5, were subjected to a control diet, HFD, or HFD with a return to control. We isolated ISCs by flow cytometry and used an assay for transposase-accessible chromatin sequencing (ATAC-seq) to identify differentially accessible genomic regions correlated with the ISC phenotype. We found that a HFD induces distinct changes in the chromatin landscape that persist after removal from the HFD. These accessible regions are associated with genes involved in lipid metabolism and are enriched with PPAR (Peroxisome Proliferator-Activated Receptor) binding motifs. We demonstrate that these lipid metabolism regulators, PPAR-delta and PPAR-alpha, are necessary for the majority of significant accessible regions. We further show that HFD-induced accessibility significantly correlates with early chromatin alterations seen by loss of tumor suppressor APC. Our data supports a mechanistic pathway for diet-induced epigenetic reprogramming due to PPAR activity and suggests that the HFD imposes a preneoplastic stem cell chromatin state that stokes the risk of oncogenic change. Citation Format: Dominic R. Saiz, Thomas Hartley-McDerrmott, Yesenia Barrera-Millan, Karla Fabiola Castro-Ochoa, Abhigyan Shukla, Matthew Torel, Miyeko D. Mana. PPARsing epigenetic memory in intestinal stem cells: High-fat diet and oncogenic susceptibility [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1247.

Abstract 7446: Transcriptomic and histological analysis of radiation-induced damage in the murine submandibular gland

Abstract Many head and neck cancer patients develop radiation-induced xerostomia (RIX). There are few clinical solutions for this condition and there is a critical need for novel therapeutics for this condition. To better understand the molecular alterations induced by radiation to the salivary glands, we used transcriptional profiling to assess acute and long-term alterations. Based on evidence that immunologic changes are induced by radiation, we used immune-depletion experiments to investigate the role of B-cells and macrophages in RIX. The submandibular gland (SMG) of male-C57/BL6-mice was irradiated (15Gy) mice were followed for 90 days. Saliva was collected throughout the time-course. SMGs were collected 3-, 7-, 60-, and 90-days following radiation. Tissues were analyzed by Nanostring Digital-Spatial-Profiling (DSP) utilizing the murine whole-transcriptome panel. Regions of interest corresponding to acini, ducts, and granular convoluted tubules (GCTs) were delineated and gene expression was assessed. Immunohistochemical staining was performed on SMG’s for fibrosis (masons trichrome), α-amylase, F4/80, Lgr5, Sox2, and MIST1 to evaluate glandular structure, salivary proteins, immune-microenvironment and pro-acinar salivary-stem-cell presence. Specific immune populations were depleted using anti-CD20 and clodronate-liposome prior to radiation and salivary function and histology was assessed at 3-, 7-, and 60-days following radiation. Radiation resulted in a significant decrease in salivary production (p-value = 0.03) in immune competent models. Transcriptional pathway analysis identified early alterations in signal-transduction and innate immune-response. Late timepoints identified alterations in B-cell activity and Wnt signaling pathways. Histological evaluation of the tissues showed increased disorganization of the gland, with decreases in size and distribution of the acinar compartments (mean area stained: No RT=25.81% vs 90d RT=19.98%, p-value=0.005). Acutely, there was an increase in expression of MIST1 and macrophages (mean area stained: No RT=14.8% vs 7d RT=18.76%, p-value=0.0004) within the SMG that resolved by the 60- and 90-day time-points. Results of immune depletion studies will be presented.Results implicate alterations in macrophages and B-cells in radiation-induced damage. These data along with the data from our immune-depletion experiments will provide valuable mechanistic insight guiding modulation of cell-therapies for treatment of RIX which can be further tested in preclinical models. Citation Format: Cristina Paz, Annemarie Glassey, Abigail Frick, Lauryn Melzer, Jasmine M. Robinson, Rebecca M. Baus, Randall J. Kimple. Transcriptomic and histological analysis of radiation-induced damage in the murine submandibular gland [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7446.

A sex-specific pathway linking early life maltreatment, vagal activity, and depressive symptoms

ABSTRACT Background: Experiences of early life maltreatment (ELM) are alarmingly common and represent a risk factor for the development of psychopathology, particularly depression. Research has focused on alterations in autonomic nervous system (ANS) functioning as a mediator of negative mental health outcomes associated with ELM. Early alterations in autonomic vagal activity (vmHRV) may moderate the relationship between ELM and depression, particularly when considering forms of emotional maltreatment. Recent evidence suggests that the relationships of both ELM and vmHRV with depression may be non-linear, particularly considering females. Objective: Building on and extending theoretical considerations and previous work, the present work aims to further the current understanding of the complex relationships between ELM exposure, vmHRV, and depression. Methods: This study uses an adaptive modelling approach, combining exploratory network-based analyses with linear and quadratic moderation analyses, drawing on a large sample of males and females across adolescence (total N = 213; outpatient at-risk sample and healthy controls) and adulthood (total N = 85; community-based convenience sample). Results: Exploratory network-based analyses reveal that exposure to emotional abuse is particularly central within a network of ELM subtypes, depressive symptoms, and concurrent vmHRV in both adolescents and adults. In adults, emotional neglect shows strong associations with both emotional abuse and vmHRV and is highly central as a network node, which is not observed in adolescents. Moderator analyses reveal significant interactions between emotional maltreatment and vmHRV predicting depressive symptoms in adult females. Significant quadratic relationships of emotional maltreatment and vmHRV with depression are observed in both adolescent and adult females. Conclusions: The present findings contribute to the understanding of the psychological and physiological mechanisms by which ELM acts as a risk factor for the development of depression. Ultimately, this will contribute to the development of targeted and effective intervention strategies to mitigate the detrimental effects of early adversity.

Bearded capuchin monkeys as a model for Alzheimer's disease.

The absence of a natural animal model is one of the main challenges in Alzheimer's disease research. Despite the challenges of using nonhuman primates in studies, these animals can bridge mouse models and humans, as nonhuman primates are phylogenetically closer to humans and can spontaneously develop AD-type pathology. The capuchin monkey, a New World primate, has recently attracted attention due to its skill in creating and using instruments. We analyzed one capuchin brain using structural 7T MRI and performed a neuropathological evaluation of three animals. Alzheimer-type pathology was found in the two of the capuchins. Widespread β-amyloid pathology was observed, mainly in focal deposits with variable morphology and a high density of mature plaques. Notably, plaque-associated dystrophic neurites associated with disruption of axonal transport and early cytoskeletal alteration were frequently found. Unlike in other species of New World monkeys, cerebral arterial angiopathy was not the predominant form of β-amyloid pathology. Additionally, abnormal aggregates of hyperphosphorylated tau, resembling neurofibrillary pathology, were observed in the temporal and frontal cortex. Astrocyte hypertrophy surrounding plaques was found, suggesting a neuroinflammatory response. These findings indicate that aged capuchin monkeys can spontaneously develop Alzheimer-type pathology, indicating that they may be an advantageous animal model for research in Alzheimer's disease.

Analyzing changes in parkinsonian speech over time: a diachronic experimental phonetics study.

In this contribution the use of web resources for the longitudinal study of speech rhythm of a 'well-known' person diagnosed with Parkinson's disease, the American actor Alan Alda, is proposed. A corpus of 20 speech samples produced in the period between 1979 and 2021 was collected from the web. A rhythmical analysis was conducted, based on two parameters: the percentage of vocalic portion on the total duration of the utterance (%V) and the VtoV, the mean duration of the interval between two consecutive vowel onset points. The results of this study confirm an early alteration of rhythm in parkinsonian speech, with an abnormal increase of %V, already occurring some years before the clinical diagnosis. The observation of speech rhythm variation can therefore be considered as the basis for the realization of a sustainable and non-invasive procedure in support to early diagnosis of Parkinson's disease.

Re-evaluation of nailfold capillaroscopy in discriminating primary from secondary Raynaud’s phenomenon and in predicting systemic sclerosis: a randomised observational prospective cohort study

ABSTRACT Background Primary Raynaud’s phenomenon (pRP) is difficult to distinguish from secondary (sRP). Although nailfold capillaroscopy (NFC) may detect early alterations, no universal criteria yet discriminate between pRP from sRP. Objectives To create and validate two NFC scores that could distinguish pRP from sRP and that could predict systemic sclerosis (SSc), respectively. Methods We performed NFC on two separate cohorts with isolated RP, and recorded number of capillaries per field, enlarged/giant capillaries, crossed/bizarre patterns, microhemorrhages, neoangiogenesis, rarefaction, edema, blood flow velocity, stasis. By multivariate regression analysis, we evaluated the adjusted prognostic role of these features in a derivation cohort of 656 patients. Results were used to construct algorithm-based prognostic scores (A and B). These scores were then tested on a confirmation cohort of 219 patients. Results Score A was unable to discriminate sRP from pRP (low negative predictive values with high positive predictive values for any cut-point); score B was unable to discriminate progression to SSc or a SSc-spectrum disorder (low positive predictive values with high negative predictive values for lower cut-points). Conclusion NFC patterns, believed as specific, showed low discriminatory power and on their own are unable to reliably discriminate sRP from pRP or predict evolution to SSc.