Publications by authors named "Mollenkopf H"

Article Synopsis
  • - Cells without p53 signaling are common in ulcerative colitis (UC) and play a key role in the development of colorectal cancer linked to UC.
  • - Epithelial injury during colitis triggers stem cells to shift to a "fetal-like" regenerative state, which is regulated by p53 signaling during colitis but not during normal conditions.
  • - The study shows that while p53 is crucial in stopping excessive regeneration in healthy cells during injury, cells lacking p53 continue proliferating due to altered glycolysis processes, which helps explain their prevalence in UC and related cancers.
View Article and Find Full Text PDF

Combining data from experiments on multispecies studies provides invaluable contributions to the understanding of basic disease mechanisms and pathophysiology of pathogens crossing species boundaries. The task of multispecies gene expression analysis, however, is often challenging given annotation inconsistencies and in cases of small sample sizes due to bias caused by batch effects. In this work we aim to demonstrate that an alternative approach to standard differential expression analysis in single cell RNA-sequencing (scRNA-seq) based on effect size profiles is suitable for the fusion of data from small samples and multiple organisms.

View Article and Find Full Text PDF

The gastroesophageal squamocolumnar junction (GE-SCJ) is a critical tissue interface between the esophagus and stomach, with significant relevance in the pathophysiology of gastrointestinal diseases. Despite this, the molecular mechanisms underlying GE-SCJ development remain unclear. Using single-cell transcriptomics, organoids, and spatial analysis, we examine the cellular heterogeneity and spatiotemporal dynamics of GE-SCJ development from embryonic to adult mice.

View Article and Find Full Text PDF
Article Synopsis
  • * In a study using gnotobiotic mice, researchers found that colibactin-producing bacteria do not harm the colonic lining under normal conditions but can cause severe injury and chronic colitis when the mucosal barrier is compromised.
  • * The presence of these bacteria leads to ongoing inflammation and damage in the colon, resembling human ulcerative colitis, and is linked to changes in tissue structure and increased levels of R-spondin 3, which further exacerbate the condition.
View Article and Find Full Text PDF

Background: The intestinal microbiota fundamentally guides the development of a normal intestinal physiology, the education, and functioning of the mucosal immune system. The Citrobacter rodentium-carrier model in germ-free (GF) mice is suitable to study the influence of selected microbes on an otherwise blunted immune response in the absence of intestinal commensals.

Results: Here, we describe that colonization of adult carrier mice with 14 selected commensal microbes (OMM + MC) was sufficient to reestablish the host immune response to enteric pathogens; this conversion was facilitated by maturation and activation of the intestinal blood vessel system and the step- and timewise stimulation of innate and adaptive immunity.

View Article and Find Full Text PDF
Article Synopsis
  • The study focuses on the stomach corpus epithelium, which consists of glands and pits, and explores how R-spondin 3 (RSPO3) regulates cell behavior and differentiation in this area.
  • RSPO3 promotes the differentiation of secretory cells into parietal and chief cells while its absence leads to the development of pit cells; high levels of RSPO3 are needed to initiate a regenerative response after cell loss.
  • However, during chronic Helicobacter pylori infection, RSPO3-driven regeneration results in excessive gland growth and increased risk of premalignant changes.
View Article and Find Full Text PDF
Article Synopsis
  • Helicobacter pylori is a pathogen that causes chronic gastritis by colonizing deep in the stomach, leading to increased R-spondin 3 (Rspo3) signaling and gland hyperplasia.
  • Lgr4 plays a crucial role in regulating Lgr5 expression, necessary for H. pylori-induced hyperplasia and inflammation, while Lgr5 alone does not drive this process.
  • R-spondin signaling through Lgr4 enhances stem cell proliferation and activates NF-κB, linking epithelial stem cell behavior with inflammatory responses during H. pylori infection.
View Article and Find Full Text PDF

Helicobacter pylori causes gastric inflammation, gland hyperplasia and is linked to gastric cancer. Here, we studied the interplay between gastric epithelial stem cells and their stromal niche under homeostasis and upon H. pylori infection.

View Article and Find Full Text PDF
Article Synopsis
  • - The research explores how coinfections with HPV16 and Chlamydia affect the cervical mucosa, utilizing patient-derived ectocervical organoids to mimic the cervical environment, which has previously limited the study of these interactions.
  • - Genetic manipulation of ectocervical stem cells created models that exhibit characteristics of precancerous lesions while still retaining their ability to develop into mature tissue, showing how HPV16 alters Chlamydia's behavior.
  • - The study reveals that Chlamydia not only disrupts HPV-induced cellular health mechanisms but also suggests that the unique interactions between these infections may contribute to an increased risk of cervical cancer.
View Article and Find Full Text PDF

Suboptimal vaccine immunogenicity and antigenic mismatch, compounded by poor uptake, means that influenza remains a major global disease. T cells recognizing peptides derived from conserved viral proteins could enhance vaccine-induced cross-strain protection. To investigate the kinetics, phenotypes, and function of influenza virus-specific CD8 resident memory T (Trm) cells in the lower airway and infer the molecular pathways associated with their response to infection .

View Article and Find Full Text PDF

Cellular stress has been associated with inflammation, yet precise underlying mechanisms remain elusive. In this study, various unrelated stress inducers were employed to screen for sensors linking altered cellular homeostasis and inflammation. We identified the intracellular pattern recognition receptors NOD1/2, which sense bacterial peptidoglycans, as general stress sensors detecting perturbations of cellular homeostasis.

View Article and Find Full Text PDF

Background And Aims: A histopathological hallmark of chronic hepatitis B virus (HBV) infection is the presence of ground glass hepatocytes (GGHs). GGHs are liver cells that exhibit eosinophilic, granular, glassy cytoplasm in light microscopy and are characterized by accumulation of HBV surface (HBs) proteins in the endoplasmic reticulum (ER). More important, GGHs have been accepted as a precursor of HCC and may represent preneoplastic lesions of the liver.

View Article and Find Full Text PDF

Colonization of the mosquito host by parasites is achieved by sexually differentiated gametocytes. Gametocytogenesis, gamete formation and fertilization are tightly regulated processes, and translational repression is a major regulatory mechanism for stage conversion. Here, we present a characterization of a RNA binding protein, UIS12, that contains two conserved eukaryotic RNA recognition motifs (RRM).

View Article and Find Full Text PDF

Apart from the constitutive proteasome, the immunoproteasome that comprises the three proteolytic subunits LMP2, MECL-1, and LMP7 is expressed in most immune cells. In this study, we describe opposing roles for immunoproteasomes in regulating the tumor microenvironment (TME). During chronic inflammation, immunoproteasomes modulated the expression of protumorigenic cytokines and chemokines and enhanced infiltration of innate immune cells, thus triggering the onset of colitis-associated carcinogenesis (CAC) in wild-type mice.

View Article and Find Full Text PDF

Systems vaccinology has been applied to detect signatures of human vaccine induced immunity but its ability, together with high definition clinical imaging is not established to predict vaccine reactogenicity. Within two European Commission funded high impact programs, BIOVACSAFE and ADITEC, we applied high resolution positron emission tomography/computed tomography (PET/CT) scanning using tissue-specific and non-specific radioligands together with transcriptomic analysis of muscle biopsies in a clinical model systematically and prospectively comparing vaccine-induced immune/inflammatory responses. 109 male participants received a single immunization with licensed preparations of either AS04-adjuvanted hepatitis B virus vaccine (AHBVV); MF59C-adjuvanted (ATIV) or unadjuvanted seasonal trivalent influenza vaccine (STIV); or alum-OMV-meningococcal B protein vaccine (4CMenB), followed by a PET/CT scan (n = 54) or an injection site muscle biopsy (n = 45).

View Article and Find Full Text PDF

Emerging mosquito-borne RNA viruses cause massive health complications worldwide. The Zika virus (ZIKV), in particular, has spread dramatically since 2007 and has provoked epidemics in the Americas and the South Pacific. The lack of antiviral therapy and vaccination has focused research on the investigation of ZIKV-host interactions, in order to understand underlying molecular infection mechanisms.

View Article and Find Full Text PDF

SARS-CoV-2, the agent that causes COVID-19, invades epithelial cells, including those of the respiratory and gastrointestinal mucosa, using angiotensin-converting enzyme-2 (ACE2) as a receptor. Subsequent inflammation can promote rapid virus clearance, but severe cases of COVID-19 are characterized by an inefficient immune response that fails to clear the infection. Using primary epithelial organoids from human colon, we explored how the central antiviral mediator IFN-γ, which is elevated in COVID-19, affects epithelial cell differentiation, ACE2 expression, and susceptibility to infection with SARS-CoV-2.

View Article and Find Full Text PDF

Successful asexual reproduction of intracellular pathogens depends on their potential to exploit host resources and subvert antimicrobial defense. In this work, we deployed two prevalent apicomplexan parasites of mammalian cells, namely and , to identify potential host determinants of infection. Expression analyses of the young adult mouse colonic (YAMC) epithelial cells upon infection by either parasite showed regulation of several distinct transcripts, indicating that these two pathogens program their intracellular niches in a tailored manner.

View Article and Find Full Text PDF
Article Synopsis
  • The squamous and columnar epithelia are areas in the cervix that can develop cancer, often starting with a process called metaplasia, where one type of cell is replaced by another.
  • Researchers used advanced technology to study the different types of cells in these areas, discovering that they come from different types of stem cells that are controlled by opposite signals from surrounding tissue.
  • In experiments with mice, they found that changes in the tissue can lead to increased growth of certain stem cells, showing how the balance of cells at the transition zone is influenced by different signals in the tissue around them.
View Article and Find Full Text PDF

The Th2 cytokine IL-13 is involved in biliary epithelial injury and liver fibrosis in patients as well as in animal models. The aim of this study was to investigate IL-13 as a therapeutic target during short term and chronic intrahepatic cholestasis in an knockout mouse model (). Lack of IL-13 protected mice transiently from cholestasis.

View Article and Find Full Text PDF

Platelets are generated in the capillaries of the lung, control hemostasis, and display immunological functions. Tuberculosis primarily affects the lung, and patients show platelet changes and hemoptysis. A role of platelets in immunopathology of pulmonary tuberculosis requires careful assessment.

View Article and Find Full Text PDF

High-grade serous ovarian cancer (HGSOC) likely originates from the fallopian tube (FT) epithelium. Here, we established 15 organoid lines from HGSOC primary tumor deposits that closely match the mutational profile and phenotype of the parental tumor. We found that Wnt pathway activation leads to growth arrest of these cancer organoids.

View Article and Find Full Text PDF

Biomarkers predictive of inflammatory events post-vaccination could accelerate vaccine development. Within the BIOVACSAFE framework, we conducted three identically designed, placebo-controlled inpatient/outpatient clinical studies (NCT01765413/NCT01771354/NCT01771367). Six antiviral vaccination strategies were evaluated to generate training data-sets of pre-/post-vaccination vital signs, blood changes and whole-blood gene transcripts, and to identify putative biomarkers of early inflammation/reactogenicity that could guide the design of subsequent focused confirmatory studies.

View Article and Find Full Text PDF

rapidly adapts to altered conditions by quorum sensing (QS), a communication system that it uses to collectively modify its behavior through the production, release, and detection of signaling molecules. QS molecules can also be sensed by hosts, although the respective receptors and signaling pathways are poorly understood. We describe a pattern of regulation in the host by the aryl hydrocarbon receptor (AhR) that is critically dependent on qualitative and quantitative sensing of quorum.

View Article and Find Full Text PDF