Meroueh, Chady

In metabolic dysfunction–associated steatohepatitis (MASH), liver sinusoidal endothelial cells (LSECs) acquire a proinflammatory phenotype termed lipotoxic endotheliopathy. We previously identified glycogen synthase kinase 3β (GSK3β) as a central signaling hub in LSECs during MASH. To elucidate the molecular mechanisms and functional outcome of lipotoxicity-induced GSK3β activation in LSECs, we utilized endothelial cell–specific Gsk3 β -KO ( Gsk3 β ΔEnd ) mice fed MASH-inducing diets. Endothelial Gsk3 β deletion significantly reduced markers of lipotoxic endotheliopathy, including adhesion molecules and chemokines, alongside liver injury, inflammation, and fibrosis. Immune profiling via flow cytometry and mass cytometry by time of flight (CyTOF) identified decreased hepatic infiltration of proinflammatory myeloid populations, particularly mature DCs in Gsk3 β ΔEnd mice. In a coculture system, GSK3β in lipotoxic LSECs promoted DCs maturation. Mechanistically, GSK3 inhibition restored lipotoxicity-induced alterations in LSEC mitochondrial morphology and respiration by regulating AMP-activated protein kinase and dynamin-related protein 1. This rescue suppressed chemokine and adhesion molecule expression, thereby limiting immune cell recruitment. Collectively, under lipotoxic stress, GSK3β amplifies mitochondrial dysfunction and inflammatory signaling in LSECs, enhancing myeloid cell homing and DC maturation. Targeting LSEC GSK3β may, therefore, represent a promising therapeutic strategy to mitigate LSEC-driven fibroinflammatory response in human MASH.

Background and Aims: Liver sinusoidal endothelial cells (LSECs) acquire a proinflammatory phenotype in metabolic dysfunction–associated steatohepatitis (MASH), characterized by enhanced expression of adhesion molecules and inflammatory mediators, a process termed lipotoxic endotheliopathy. However, the molecular drivers of this transformation remain incompletely defined. Approach and Results: We employed complementary models of lipotoxicity and MASH, including palmitate-treated primary human LSECs (in vitro), cultured precision-cut liver slices (PCLS) from MASH mice and normal human liver treated with MASH-inducing media (ex vivo), and diet-induced MASH models (in vivo). GeoMx digital spatial profiling of human MASH livers revealed enriched proinflammatory and fibrogenic signaling between LSECs and myeloid cells. Among the top upregulated genes and ligand–receptor pairs was ICAM1 , whose expression correlated with disease severity and was increased in human MASH by immunostaining. ATAC-seq on primary mouse LSECs showed enhanced chromatin accessibility at the Icam1 promoter in MASH. Chromatin immunoprecipitation confirmed enrichment of the active epigenetic mark H3K27ac and BRD4 binding at the ICAM1 promoter in human LSECs under lipotoxic stress. Mechanistically, we identified the GSK3β/c-Jun/BRD4 axis as a key regulator of ICAM1 induction in LSECs. In vivo, ICAM1-neutralizing antibody or endothelial-specific epigenetic suppression reduced hepatic inflammation, injury, and fibrosis in MASH mice. Conclusions: ICAM1 is epigenetically upregulated in LSECs during lipotoxic stress and promotes myeloid cell recruitment in MASH. Targeting the epigenetic regulation of ICAM1 may offer a novel therapeutic strategy for treating human MASH.

Abstract Background Thyroid function testing is a common laboratory service that can be optimized by implementing evidence-based algorithms. The thyroid function cascade testing approach at Mayo Clinic Labs is utilized to effectively evaluate and monitor functional thyroid status. The cascade begins with thyroid-stimulating hormone (TSH) as a screening marker. When TSH levels are normal, no additional testing is necessary. When the TSH result is abnormal, appropriate follow-up free T4, total T3, and/or TPO testing will automatically be performed. Providers at our institution can order thyroid function testing with this cascade testing approach or as standalone individual orderable tests. Initial data analysis showed patterns of TSH ordered concurrently with free T4, total T3, and/or anti-TPO. Further analysis revealed that a high number of concurrently ordered tests would not have been necessary had the algorithmic approach been followed. This opportunity for improvement led to the thyroid function testing initiative to direct providers to order the cascade test rather than individual thyroid tests, thereby reducing concurrent and unnecessary testing to improve patient care. Methods The initiative involved creating a new Epic order panel directing providers to order the cascade rather than the individual orderable tests. This intervention is a soft stop that allows providers to proceed by ordering individual tests if desired. We evaluated the impact of the initiative on test utilization, cost savings, and quality indicators using pre- and post-intervention data from all Mayo Clinic sites over a 9-month period. We compared the monthly volumes of concurrent and unnecessary orders of Free T4, Total T3, and TPO before and after the intervention. Concurrent orders were defined as tests collected from the same patient on the same date and time as TSH tests. Unnecessary orders were defined as tests that were outside the reflex range according to the thyroid function ordering algorithm. Cost savings were calculated based on the 2024 CMS reimbursement rates for the associated test CPT® codes. We also monitored and addressed feedback and requests from providers and laboratory staff throughout the initiative. Results The intervention resulted in a 20% average monthly reduction in concurrent orders and an 18% average monthly reduction in unnecessary orders of free T4, total T3, and anti-TPO tests. Estimated savings based on 2024 CMS reimbursement rates are $5,000 monthly and nearly $60,000 annually. Thyroid testing quality was also improved by aligning with clinical guidelines, reducing over-testing, and minimizing the risk of misdiagnosis. Conclusion The thyroid function testing initiative was a successful laboratory stewardship project that reduced redundant testing, improved patient care, and reduced costs. The initiative demonstrated the feasibility and effectiveness of using evidence-based reflex algorithms to optimize laboratory testing. The lessons learned include assessing all tests related to the disease condition to mitigate potential unintended increases in test usage and accounting for patient groups that are not covered by the intended algorithm*s target population. Future directions include expanding the cascade approach to other areas of laboratory medicine, evaluating the long-term outcomes of the initiative, and engaging with providers to ensure the adoption of the initiative.

Liver fibrosis is characterized by the activation of perivascular hepatic stellate cells (HSCs), the release of fibrogenic nanosized extracellular vesicles (EVs), and increased HSC glycolysis. Nevertheless, how glycolysis in HSCs coordinates fibrosis amplification through tissue zone-specific pathways remains elusive. Here, we demonstrate that HSC-specific genetic inhibition of glycolysis reduced liver fibrosis. Moreover, spatial transcriptomics revealed a fibrosis-mediated up-regulation of EV-related pathways in the liver pericentral zone, which was abrogated by glycolysis genetic inhibition. Mechanistically, glycolysis in HSCs up-regulated the expression of EV-related genes such as Ras-related protein Rab-31 ( RAB31 ) by enhancing histone 3 lysine 9 acetylation on the promoter region, which increased EV release. Functionally, these glycolysis-dependent EVs increased fibrotic gene expression in recipient HSC. Furthermore, EVs derived from glycolysis-deficient mice abrogated liver fibrosis amplification in contrast to glycolysis-competent mouse EVs. In summary, glycolysis in HSCs amplifies liver fibrosis by promoting fibrogenic EV release in the hepatic pericentral zone, which represents a potential therapeutic target.

Steatohepatitis with diverse etiologies is the most common histological manifestation in patients with liver disease. However, there are currently no specific histopathological features pathognomonic for metabolic dysfunction–associated steatotic liver disease, alcohol-associated liver disease, or metabolic dysfunction–associated steatotic liver disease with increased alcohol intake. Digitizing traditional pathology slides has created an emerging field of digital pathology, allowing for easier access, storage, sharing, and analysis of whole-slide images. Artificial intelligence (AI) algorithms have been developed for whole-slide images to enhance the accuracy and speed of the histological interpretation of steatohepatitis and are currently employed in biomarker development. Spatial biology is a novel field that enables investigators to map gene and protein expression within a specific region of interest on liver histological sections, examine disease heterogeneity within tissues, and understand the relationship between molecular changes and distinct tissue morphology. Here, we review the utility of digital pathology (using linear and nonlinear microscopy) augmented with AI analysis to improve the accuracy of histological interpretation. We will also discuss the spatial omics landscape with special emphasis on the strengths and limitations of established spatial transcriptomics and proteomics technologies and their application in steatohepatitis. We then highlight the power of multimodal integration of digital pathology augmented by machine learning (ML)algorithms with spatial biology. The review concludes with a discussion of the current gaps in knowledge, the limitations and premises of these tools and technologies, and the areas of future research.

Abstract Pancreatic ductal adenocarcinoma (PDAC) is predicted to be the second cause of cancer death in the US by 2040. Five-year overall survival is only ~12% despite decades of research. The mainstay of treatment remains chemotherapy in the absence of highly recurrent, therapeutically actionable, genetic targets. For the minority of patients (~15-20%) who are candidates for curative-intent surgical resection, six months of intensive neoadjuvant chemotherapy with/without chemoradiation has become standard-of-care. However, despite evidence of radiographic, metabolic, and biochemical responses, significant viable residual disease on pathologic analysis is almost universally observed with approximately 40-60% risk of disease recurrence. Thus, there is a critical need to better understand why PDAC remains recalcitrant to current therapeutic modalities. Pathologic evaluation of PDAC reveals a complex microenvironment consisting of neoplastic cells dynamically interacting with both “normal” cellular (e.g. mesenchymal, immune) and non-cellular (e.g. collagen) stromal elements. While biologically important, experimental models and small-scale efforts to dissect the PDAC ecosystem are limited by focus on individual tumor compartments and generation of conflicting results. Consequently, there is a need for a more comprehensive understanding of the structure and dynamics of the PDAC TME through the theoretical lens of evolutionary ecology. Current therapies are not focused on the PDAC ecosystem. We hypothesize that cell-cell interactions of PDAC cells with its local niche are important for conferring treatment resistance. Thus, better understanding of said interactions could yield novel ecologically-informed therapies. Consequently, we developed a digital pathology library of approximately 1000 PDAC resection cases (whole-slide H&E images) performed at Mayo Clinic between 2013-2021. Approximately 400 cases are treatment naive while about 600 were treated with neoadjuvant therapy. While some qualitative features of pathologic analysis have prognostic value (e.g., pathologic treatment response, presence of perineural or lymphovascular invasion, extent of desmoplasia), we aim to identify prognostic spatial relationships using tools from landscape ecology. We utilized the HoVer-Net model for nuclei segmentation and classification and spatial statistics methods and landscape fragmentation analysis to understand the spatial organization within the PDAC tumor ecology. With these methodologies, we can assess the spatial context of cell interactions, habitat/niche/microenvironment formation, ecological relationships between cell populations, and the different tissue components. The different spatial statistics/metrics are used to quantify levels of immune cell infiltration, mixing, as well as the complexity and diversity of microenvironment phenotypes leading to high levels of tumor heterogeneity. Such measurements can help predict the likelihood of a PDAC tumor adaptive potential that could lead to fast evolutionary responses to therapy, progression, and poor prognosis. Citation Format: Merih D. Toruner, Luis Cisneros, Zafar Siddiqui, Chady Meroueh, Ritambhara Singh, Carlo Maley, Martin E. Fernandez-Zapico, Ryan M. Carr. Dissecting the pancreatic cancer microenvironment using landscape ecology [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Translating Cancer Evolution and Data Science: The Next Frontier; 2023 Dec 3-6; Boston, Massachusetts. Philadelphia (PA): AACR; Cancer Res 2024;84(3 Suppl_2):Abstract nr B026.

AbstractBackgroundObtaining a diagnosis and treating pulmonary malignancies during the same anesthesia requires either an on‐site pathologist or a system for remotely evaluating microscopic images. Cytology specimens are challenging to remotely assess given the need to navigate through dispersed and three‐dimensional cell clusters. Remote navigation is possible using robotic telepathology, but data are limited on the ease of use of current systems, particularly for pulmonary cytology.MethodsAir dried modified Wright‐Giemsa stained slides from 26 touch preparations of transbronchial biopsies and 27 smears of endobronchial ultrasound guided fine needle aspirations were scored for ease of adequacy assessment and ease of diagnosis on robotic (rmtConnect Microscope) and non‐robotic telecytology platforms. Diagnostic classifications were compared between glass slides and the robotic and non‐robotic telecytology assessments.ResultsCompared to non‐robotic telecytology, robotic telecytology had a greater ease of adequacy assessment and non‐inferior ease of diagnosis. The median time to diagnosis using robotic telecytology was 85 s (range 28–190 s). Diagnostic categories were concordant for 76% of cases in robotic versus non‐robotic telecytology and 78% of cases in robotic telecytology versus glass slide diagnosis. Weighted Cohen's kappa scores for agreement in these comparisons were 0.84 and 0.72, respectively.ConclusionsUse of a remote‐controlled robotic microscope improved the ease of adequacy assessment compared to non‐robotic telecytology and enabled strongly concordant diagnoses to be expediently rendered. This study provides evidence that modern robotic telecytology is a feasible and user‐friendly method of remotely and potentially intraoperatively rendering adequacy assessments and diagnoses on bronchoscopic cytology specimens.

SummaryBoth genetic and environmental factors contribute to autoimmune disease development. Previously, we evaluated genetic factors in a humanized mouse model of Hashimoto's thyroiditis (HT) by immunizing human leucocyte antigen DR3 (HLA-DR3) and HLA-DQ8 transgenic class II-knock-out non-obese diabetic (NOD) mice. DR3+ mice were susceptible to experimental autoimmune thyroiditis (EAT) induction by both mouse thyroglobulin (mTg) and human (h) Tg, while DQ8+ mice were weakly susceptible only to hTg. As one environmental factor associated with HT and tested in non-transgenic models is increased sodium iodide (NaI) intake, we examined the susceptibility of DR3+ and/or DQ8+ mice to NaI-induced disease. Mice were treated for 8 weeks with NaI in the drinking water. At 0·05% NaI, 23% of DR3+, 0% of DQ8+ and 20% of DR3+DQ8+ mice had thyroid destruction. No spleen cell proliferation to mTg was observed. Most mice had undetectable anti-mTg antibodies, but those with low antibody levels usually had thyroiditis. At 0·3% NaI, a higher percentage of DR3+ and DR3+DQ8+ mice developed destructive thyroiditis, but it was not statistically significant. However, when DR3+ mice had been depleted of CD4+CD25+ regulatory T cells prior to NaI treatment, destructive thyroiditis (68%) and serum anti-mTg antibodies were exacerbated further. The presence of DQ8 molecules does not alter the susceptibility of DR3+DQ8+ mice to NaI-induced thyroiditis, similar to earlier findings with mTg-induced EAT. Susceptibility of DR3+ mice to NaI-induced EAT, in both the presence and absence of regulatory T cells, demonstrates the usefulness of HLA class II transgenic mice in evaluating the roles of environmental factors and immune dysregulation in autoimmune thyroid disease.

Abstract Immune reactivity to self-antigens in both cancer and autoimmune diseases can be enhanced by systemic immune modulation, posing a challenge in cancer immunotherapy. To distinguish the genetic and immune regulation of tumor immunity versus autoimmunity, immune responses to human ErbB-2 (Her-2) and mouse thyroglobulin (mTg) were tested in transgenic mice expressing Her-2 that is overexpressed in several cancers, and HLA-DRB1*0301 (DR3) that is associated with susceptibility to several human autoimmune diseases, as well as experimental autoimmune thyroiditis (EAT). To induce Her-2 response, mice were electrovaccinated with pE2TM and pGM-CSF encoding the extracellular and transmembrane domains of Her-2 and the murine granulocyte macrophage colony-stimulating factor, respectively. To induce EAT, mice received mTg i.v. with or without lipopolysaccharide. Depletion of regulatory T cells (Treg) with anti-CD25 monoclonal antibody enhanced immune reactivity to Her-2 as well as mTg, showing control of both Her-2 and mTg responses by Treg. When immunized with, Her-2xDR3 and B6xDR3 mice expressing H2bxDR3 haplotype developed more profound mTg response and thyroid pathology than Her-2 or B6 mice that expressed the EAT-resistant H2b haplotype. In Her-2xDR3 mice, the response to mTg was further amplified when mice were also immunized with pE2TM and pGM-CSF. On the contrary, Her-2 reactivity was comparable whether mice expressed DR3 or not. Therefore, induction of Her-2 immunity was independent of DR3 but development of EAT was dictated by this allele, whereas Tregs control the responses to both self-antigens. These results warrant close monitoring of autoimmunity during cancer immunotherapy, particularly in patients with susceptible MHC class II alleles. [Cancer Res 2007;67(14):7020–7]