Bioengineering Center Analytical Pathology
The Research Unit Analytical Pathology (AAP) builds on clinical pathology and expands it by the inclusion and development of the very latest methods for tissue analysis. Analytical Pathology opens up new directions for reverse translational research, molecular imaging pathology, digital pathology, and machine learning and pathology-related omics data.
The Research Unit Analytical Pathology (AAP) carries out scientific development, as a complement to research units with a clinical and fundamental orientation of translational research on diseases that occur in tissue.
Core Facility Pathology
About our Research
Our research includes two areas of research activity. One is the process of applying discoveries generated during research in the laboratory, and in preclinical studies, to the development of trials and studies in humans. The second area concerns research aimed at enhancing the adoption of best practices in the community.
Recent Publications
Read more2025 Scientific Article in Molecular Pharmaceutics
Long-acting human PASylated leptin reaches the murine central nervous system and offers potential for optimized replacement therapy.
Despite the multifaceted role of leptin for energy homeostasis and its broad therapeutic potential, the FDA/EMA-approved metreleptin constitutes the only leptin drug to date. To translate the promising results from previous studies on murine PASylated leptin with improved solubility and extended plasma half-life using PASylation technology─a biological alternative to PEGylation─we have developed a second-generation human leptin drug candidate and tested it rigorously in vitro and in vivo. To this end, the exposed hydrophobic Trp residue at position 100 in human leptin was replaced by Gln, which, together with the genetic fusion with a 600-residue PAS polypeptide, yielded a protein with high solubility, folding stability and receptor-stimulatory activity. In a pharmacokinetic (PK) study with wild-type mice, this modified human leptin showed an extended plasma half-life of 18.8 ± 3.6 h after subcutaneous (s.c.) injection. Furthermore, leptin-deficient mice were dosed s.c. with the modified human leptin carrying two different PAS fusion tags, PAS#1 or P/A#1, each comprising 600 residues. After only four doses, the disease phenotype, including morbid adiposity, hyperphagia, and hepatic steatosis, was completely reversed by both PASylated leptin versions, but not by the non-PASylated leptin if administered at the same dose. To assess its tissue distribution, P/A(200)-huLeptinW100Q was doubly labeled with two fluorescent dyes, which were specifically attached to the leptin and the PAS moiety, respectively. Analysis of relevant mouse organs by light sheet fluorescence microscopy after clearance revealed colocalized signals in the kidney and liver, thus indicating general stability of the PAS-leptin fusion protein in vivo. However, discrete signals were observed in the hypothalamic region, only with leptin detectable in the choroid plexus, which implies cleavage of the PAS tag during transcytosis across the physiological barriers. This study should pave the way toward a second-generation leptin drug enabling prolonged dosing intervals.
2025 Scientific Article in Molecular Metabolism
Estrogenic activity of E2-conjugated GLP-1 is mediated by intracellular endolysosomal acidification and estrone metabolism.
Recent modifications to glucagon-like peptide 1 (GLP-1), known for its insulinotropic and satiety-inducing effects, have focused on conjugating small molecules to enable selective delivery into GLP-1R+ tissues to achieve targeted synergy and improved metabolic outcomes. Despite continued advancements in GLP-1/small molecule conjugate strategies, the intracellular mechanisms facilitating concurrent GLP-1R signaling and small molecule cargo release remain poorly understood. We evaluate an estradiol (E2)-conjugated GLP-1 (GLP-1-CEX/E2) for relative differences in GLP-1R signaling and trafficking, and elucidate endolysosomal dynamics that lead to estrogenic activity using various live-cell, reporter, imaging, and mass-spectrometry techniques. We find GLP-1-CEX/E2 does not differentially activate or traffic the GLP-1R relative to its unconjugated GLP-1 backbone (GLP-1-CEX), but uniquely internalizes the E2 moiety and stimulates estrogenic signaling. Endolysosomal pH-dependent proteolytic activity likely mediates E2 moiety liberation, as evidenced by clear amplification in estrogenic activity following co-administration with lysosomal VATPase activator EN6. The hypothesized liberated metabolite from GLP-1-CEX/E2, E2-3-ether, exhibits partial estrogenic efficacy through ERα, and is predisposed toward estrone-3-sulfate conversion. Finally, we identify relative increases in intracellular E2, estrone, and estrone-3-sulfate following GLP-1-CEX/E2 incubation in GLP-1R+ cells, demonstrating proof-of-principle for desired cargo release. Together, our data suggest that GLP-1-CEX/E2 depends on GLP-1R trafficking and lysosome acidification for estrogenic efficacy, with a likely conversion of the liberated E2-3-ether metabolite into estrone-3-sulfate, resulting in residual downstream flux into active estradiol. Our current findings aim to improve the understanding of small molecule targeting and the efficacy behind GLP-1/small molecule conjugates.
2025 Scientific Article in OncoImmunology
Metabolic heterogeneity in tumor cells impacts immunology in lung squamous cell carcinoma.
Metabolic processes are crucial in immune regulation, yet the impact of metabolic heterogeneity on immunological functions remains unclear. Integrating metabolomics into immunology allows the exploration of the interactions of multilayered features in the biological system and the molecular regulatory mechanism of these features. To elucidate such insight in lung squamous cell carcinoma (LUSC), we analyzed 106 LUSC tumor tissues. We performed high-resolution matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) to obtain spatial metabolic profiles, and immunohistochemistry to detect tumor-infiltrating T lymphocytes (TILs). Unsupervised k-means clustering and Simpson's diversity index were employed to assess metabolic heterogeneity, identifying five distinct metabolic tumor subpopulations. Our findings revealed that TILs are specifically associated with metabolite distributions, not randomly distributed. Integrating a validation cohort, we found that heterogeneity-correlated metabolites interact with CD8+ TIL-associated genes, affecting survival. High metabolic heterogeneity was linked to worse survival and lower TIL levels. Pathway enrichment analyses highlighted distinct metabolic pathways in each subpopulation and their potential responses to chemotherapy. This study uncovers the significant impact of metabolic heterogeneity on immune functions in LUSC, providing a foundation for tailoring therapeutic strategies.
2024 Scientific Article in Scientific Reports
Dipeptide metabolite, glutamyl-glutamate mediates microbe-host interaction to boost spermatogenesis.
The decrease in sperm count and infertility is a global issue that remains unresolved. By screening environmental bacterial isolates, we have found that a novel lactic acid bacterium, Lactiplantibacillus plantarum SNI3, increased testis size, testosterone levels, sperm count, sexual activity and fertility in mice that have consumed the bacteria for four weeks. The abundance of L. plantarum in the colon microbiome was positively associated with sperm count. Fecal microbiota transplantation (FMT) from L. plantarum SNI3-dosed mice improved testicular functions in microbiome-attenuated recipient animals. To identify mediators that confer pro-reproductive effects on the host, untargeted in situ mass spectrometry metabolomics was performed on testis samples of L. plantarum SNI3-treated and control mice. Enrichment pathway analysis revealed several perturbed metabolic pathways in the testis of treated mice. Within the testis, a dipeptide, glutamyl-glutamate (GluGlu) was the most upregulated metabolite following L. plantarum SNI3 administration. To validate the pro-reproductive feature of GluGlu, systemic and local injections of the dipeptide have been performed. γ-GluGlu increased sperm count but had no effect on testosterone. These findings highlight the role of γ-GluGlu in mediating spermatogenetic effects of L. plantarum on the male mouse host and -following relevant human clinical trials- may provide future tools for treating certain forms of male infertility.
2024 Scientific Article in Metabolism: clinical and experimental
Inter-organ cross-talk in human cancer cachexia revealed by spatial metabolomics.
BACKGROUND: Cancer cachexia (CCx) presents a multifaceted challenge characterized by negative protein and energy balance and systemic inflammatory response activation. While previous CCx studies predominantly focused on mouse models or human body fluids, there's an unmet need to elucidate the molecular inter-organ cross-talk underlying the pathophysiology of human CCx. METHODS: Spatial metabolomics were conducted on liver, skeletal muscle, subcutaneous and visceral adipose tissue, and serum from cachectic and control cancer patients. Organ-wise comparisons were performed using component, pathway enrichment and correlation network analyses. Inter-organ correlations in CCx altered pathways were assessed using Circos. Machine learning on tissues and serum established classifiers as potential diagnostic biomarkers for CCx. RESULTS: Distinct metabolic pathway alteration was detected in CCx, with adipose tissues and liver displaying the most significant (P ≤ 0.05) metabolic disturbances. CCx patients exhibited increased metabolic activity in visceral and subcutaneous adipose tissues and liver, contrasting with decreased activity in muscle and serum compared to control patients. Carbohydrate, lipid, amino acid, and vitamin metabolism emerged as highly interacting pathways across different organ systems in CCx. Muscle tissue showed decreased (P ≤ 0.001) energy charge in CCx patients, while liver and adipose tissues displayed increased energy charge (P ≤ 0.001). We stratified CCx patients by severity and metabolic changes, finding that visceral adipose tissue is most affected, especially in cases of severe cachexia. Morphometric analysis showed smaller (P ≤ 0.05) adipocyte size in visceral adipose tissue, indicating catabolic processes. We developed tissue-based classifiers for cancer cachexia specific to individual organs, facilitating the transfer of patient serum as minimally invasive diagnostic markers of CCx in the constitution of the organs. CONCLUSIONS: These findings support the concept of CCx as a multi-organ syndrome with diverse metabolic alterations, providing insights into the pathophysiology and organ cross-talk of human CCx. This study pioneers spatial metabolomics for CCx, demonstrating the feasibility of distinguishing cachexia status at the organ level using serum.
2024 Scientific Article in npj Precision Oncology
Metabolic pathway-based subtypes associate glycan biosynthesis and treatment response in head and neck cancer.
Head and Neck Squamous Cell Carcinoma (HNSCC) is a heterogeneous malignancy that remains a significant challenge in clinical management due to frequent treatment failures and pronounced therapy resistance. While metabolic dysregulation appears to be a critical factor in this scenario, comprehensive analyses of the metabolic HNSCC landscape and its impact on clinical outcomes are lacking. This study utilized transcriptomic data from four independent clinical cohorts to investigate metabolic heterogeneity in HNSCC and define metabolic pathway-based subtypes (MPS). In HPV-negative HNSCCs, MPS1 and MPS2 were identified, while MPS3 was enriched in HPV-positive cases. MPS classification was associated with clinical outcome post adjuvant radio(chemo)therapy, with MPS1 consistently exhibiting the highest risk of therapeutic failure. MPS1 was uniquely characterized by upregulation of glycan (particularly chondroitin/dermatan sulfate) metabolism genes. Immunohistochemistry and pilot mass spectrometry imaging analyses confirmed this at metabolite level. The histological context and single-cell RNA sequencing data identified the malignant cells as key contributors. Globally, MPS1 was distinguished by a unique transcriptomic landscape associated with increased disease aggressiveness, featuring motifs related to epithelial-mesenchymal transition, immune signaling, cancer stemness, tumor microenvironment assembly, and oncogenic signaling. This translated into a distinct histological appearance marked by extensive extracellular matrix remodeling, abundant spindle-shaped cancer-associated fibroblasts, and intimately intertwined populations of malignant and stromal cells. Proof-of-concept data from orthotopic xenotransplants replicated the MPS phenotypes on the histological and transcriptome levels. In summary, this study introduces a metabolic pathway-based classification of HNSCC, pinpointing glycan metabolism-enriched MPS1 as the most challenging subgroup that necessitates alternative therapeutic strategies.
2024 Review in Heliyon
Decoding the genomic enigma: Approaches to studying extrachromosomal circular DNA.
Extrachromosomal circular DNA (eccDNA), a pervasive yet enigmatic component of the eukaryotic genome, exists autonomously from its chromosomal counterparts. Ubiquitous in eukaryotes, eccDNA plays a critical role in the orchestration of cellular processes and the etiology of diseases, particularly cancers. However, the full scope of its influence on health and disease remains elusive, presenting a rich vein of research yet to be mined. Unraveling the complexities of eccDNA necessitates a distillation of methodologies — from biogenesis to functional analysis — a landscape we overview in this study with precision and clarity. Here, we systematically outline cutting-edge methodologies from high-throughput sequencing and bioinformatics to experimental validations, showcasing the intricate world of eccDNAs. We combed through a treasure trove of auxiliary research resources and analytical tools. Moreover, we chart a course for future inquiry, illuminating the horizon with potential groundbreaking strategies for designing eccDNA research projects and pioneering new methodological frontiers.
2024 Scientific Article in Journal of Controlled Release
Tuning the photophysical properties of cyanine by barbiturate functionalization and nanoformulation for efficient optoacoustics- guided phototherapy.
Cyanine derivatives are organic dyes widely used for optical imaging. However, their potential in longitudinal optoacoustic imaging and photothermal therapy remains limited due to challenges such as poor chemical stability, poor photostability, and low photothermal conversion. In this study, we present a new structural modification for cyanine dyes by introducing a strongly electron-withdrawing group (barbiturate), resulting in a new series of barbiturate-cyanine dyes (BC810, BC885, and BC1010) with suppressed fluorescence and enhanced stability. Furthermore, the introduction of BC1010 into block copolymers (PEG114-b-PCL60) induces aggregation-caused quenching, further boosting the photothermal performance. The photophysical properties of nanoparticles (BC1010-NPs) include their remarkably broad absorption range from 900 to 1200 nm for optoacoustic imaging, allowing imaging applications in NIR-I and NIR-II windows. The combined effect of these strategies, including improved photostability, enhanced nonradiative relaxation, and aggregation-caused quenching, enables the detection of optoacoustic signals with high sensitivity and effective photothermal treatment of in vivo tumor models when BC1010-NPs are administered before irradiation with a 1064 nm laser. This research introduces a barbiturate-functionalized cyanine derivative with optimal properties for efficient optoacoustics-guided theranostic applications. This new compound holds significant potential for biomedical use, facilitating advancements in optoacoustic-guided diagnostic and therapeutic approaches.
Previous Funding by Deutsche Forschungsgemeinschaft
Previous Funding by Bundesministerium für Bildung und Forschung
SYS-Stomach: Systemmedizinischer Forschungsansatz zur Response- und Resistenzprädiktion zielgerichteter Therapien beim Magenkarzinom
2. Förderperiode, Verbundprojekt Sys-Stomach / Teilprojekt 5 „In-situ Proteom und Metabolomanalyse des Magenkarzinoms“
SYS-Stomach: Systemmedizinischer Forschungsansatz zur Response- und Resistenzprädiktion zielgerichteter Therapien beim Magenkarzinom
1. Förderperiode, Verbundprojekt Sys-Stomach / Teilprojekt 5 „In-situ Proteom und Metabolomanalyse des Magenkarzinoms“
„MALDI-AMK - 3D MALDI Imaging zur Analyse proteomischer Marker und klinischer Wirkstoffverteilung"
„Multimodal Proteome Imaging: an Entry to Biomedical Tissue Systems Biology“
„Verbund EndoMed: Frühdiagnose von intraepithelialen Neoplasien und Karzinomen des Magens mittels molekularer Fluoreszenzendoskopie“ (Teilprojekt 4: „Identifizierung von neuen molekularen Zielstrukturen für die in vivo Bildgebung von ...
Previous Funding by others
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Deutsche Krebshilfe “High throughput in situ metabolomics in adrenal tumors”
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