Biology subjects

Yagel, S.

Publications and source records attributed to Yagel, S..

5 recordsLinked to original sources

bioRxiv2024

Human adipose-derived mesenchymal stromal cells improved wound healing in enterocutaneous fistulizing disease mouse model

A significant complication of Crohns disease is the formation of perianal fistulas. While local application of human adipose tissue-derived mesenchymal stromal cells (AT-MSC INN Darvadstrocel, Takeda) is an approved therapy for this condition, challenges in studying human clinical tissue and the absence of a robust experimental model have hindered deeper understanding of the preclinical efficacy and mechanisms behind the therapy. We have developed a model that closely mimics the clinical scenario, using human gut tissue transplanted subcutaneously into SCID mice. In this model, enterocutaneous fistulas are reliably induced by combining imiquimod-induced psoriatic dermatitis above the transplant with systemic lipopolysaccharide (LPS), a major component of the bacterial cell wall. Similar to clinical observations, local application of AT-MSC significantly improved fistula wound healing and re-epithelialization. This model system enabled comprehensive tissue harvesting for histopathological analysis, spatial transcriptomics, and protein profiling. Our findings demonstrate that AT-MSC applied around the fistula wound survive for up to three weeks, migrating into the fistula tract and further into the inflamed human gut tissue. Within the fistula tract, AT-MSCs acquired immune-active properties, with increased expression of SOD2 and CCL2, and were associated with a substantial population of M2 macrophages. In contrast, AT-MSC located in healthy tissue near the fistula remained stationary, adopting a fibroblast-like phenotype within a collagen-rich extracellular matrix. These preclinical results support the safety and efficacy of AT-MSC for treating fistulizing gut disease. Furthermore, our data suggest that the inflamed fistula tract acts as a scaffold promoting AT-MSC activity and migration. Enhancing SOD2 and CCL2 expression through pre-activation or genetic modification may further improve the therapeutic potential of these cells.

pathology↗

bioRxiv2024

Natural killer cell function is regulated by TGF-β signaling in pregnancy and tumor progression

The immune compartment of the maternal-fetal interface must balance between supporting maternal-fetal interactions and maintaining maternal tolerance. Despite recent advances, the cellular and molecular regulators that drive maternal immune cell remodeling remain largely unknown. Using index and transcriptional single-cell sorting, we comprehensively characterized the immune compartment dynamics in the maternal-fetal interface of both human and mouse and charted the markers and functional pathways associated with these cells. Comparing immune signatures in decidua and tumors of human and mice, we identify conserved gene modules that are activated in natural killer (NK) cells of both compartments, including TFG-{beta} signaling. Genetic ablation and antibody blockade of the TGF-{beta} pathway in NK cells resulted in enhanced anti-tumor immunity.

immunology↗

bioRxiv2021

Pluripotency-Independent Induction of Human Trophoblast Stem Cells from Fibroblasts

Recent studies demonstrated that human trophoblast stem-like cells (hTS-like cells) can be derived from naive embryonic stem cells or be induced from somatic cells by the pluripotency factors, OSKM. This raises two main questions; (i) whether human induced TSCs (hiTSCs) can be generated independently to pluripotent state or factors and (ii) what are the mechanisms by which hTSC state is established during reprogramming. Here, we identify GATA3, OCT4, KLF4 and MYC (GOKM) as a pluripotency-independent combination of factors that can generate stable and functional hiTSCs, from both male and female fibroblasts. By using single and double knockout (KO) fibroblasts for major pluripotency genes (i.e. SOX2 or NANOG/PRDM14) we show that GOKM not only is capable of generating hiTSCs from the KO cells, but rather that the efficiency of the process is increased. Through H3K4me2 and chromatin accessibility profiling we demonstrate that GOKM target different loci and genes than OSKM, and that a significant fraction of them is related to placenta and trophoblast function. Moreover, we show that GOKM exert a greater pioneer activity compared to OSKM. While GOKM target many specific hTSC loci, OSKM mainly target hTSC loci that are shared with hESCs. Finally, we reveal a gene signature of trophoblast-related genes, consisting of 172 genes which are highly expressed in blastocyst-derived TSCs and GOKM-hiTSCs but absent or mildly expressed in OSKM-hiTSCs. Taken together, these results imply that not only is the pluripotent state, and SOX2 specifically, not required to produce functional hiTSCs, but that pluripotency-specific factors actually interfere with the acquisition of the hTSC state during reprogramming.

cell biology↗

bioRxiv2021

Hyperinflammation evokes different antiviral TMPRSS2 and ADAM17 expression responses in human gut xenograft versus host mouse gut although overall genomic responses are similar

The global spread of the newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to the pandemic outbreak of coronavirus disease 2019 (COVID-19), an inflammatory disease that is primarily affecting the respiratory system. However, gastrointestinal symptoms in COVID-19 patients suggests that the gut may present another viral target organ. Disease development and severity is dependent on viral interaction with two cell surface human proteins, ACE2 and TMPRSS2, and on antiviral response which may lead to systemic hyperinflammatory syndrome and multiorgan dysfunction. Understanding the host response to SARS-CoV-2 infection and the pathology of the disease will be greatly enhanced by the development of appropriate animal models. Laboratory mice have been the mainstay of therapeutic and vaccine development, however, the virus does not grow in wild type mice and only induced mild disease in transgenic animals expressing human ACE2. As there are known differences between immune response in laboratory mice and humans we evaluated the response of human gut developed as xenografts and host mouse gut following systemic LPS injections as a hyperinflammation model system. The orthologous gene expression levels in the mouse and human gut were highly correlated (Spearmans rank correlation coefficient: 0.28-0.76) and gene set enrichment analysis of significantly upregulated human and mouse genes revealed that a number of inflammatory and immune response pathways are commonly regulated in the two species. However, species differences were also observed, most importantly, in the inflamed human gut but not in the mouse gut, there was clear upregulation of mRNAs coding for TMPRSS2, ADAM17 and for RIG-I-like receptors, which are involved in the recognition of viruses and in antiviral innate immune response. Moreover, using species-specific immunofluorescence microscopy, we demonstrated the expression and localization of human ACE2 and TMPRSS2 proteins, which are essential elements of the molecular machinery that enables SARS-CoV-2 to infect and replicate in human gut cells. Our findings demonstrate that the intestinal immune response to inflammation in humans and mice are generally very similar. However, certain human-specific diseases, such as COVID-19, can only be successfully studied in an experimental model of human tissue, such as the gut xenograft.

immunology↗

bioRxiv2020

NF-kappa-B activation unveils the presence of inflammatory hotspots in human gut xenografts

The single-epithelial cell layer of the gut mucosa serves as an essential barrier between the host and luminal microflora and plays a major role in innate immunity against invading pathogens. Nuclear factor kB (NF-{kappa}B), a central component of the cellular signaling machinery, regulates immune response and inflammation. NF-{kappa}B proteins are activated by signaling pathways downstream to microbial recognition receptors and cytokines receptors. Highly regulated NF-{kappa}B activity in intestinal epithelial cells (IEC) is essential for normal gut homeostasis; dysregulated activity has been linked to a number of disease states, including inflammatory bowel diseases (IBD) such as Crohns Disease (CD). Our aim was to visualize and quantify spatial and temporal dynamics of NF-{kappa}B activity in steady state and inflamed human gut. Lentivirus technology was used to transduce the IEC of human gut xenografts in SCID mice with a NF-{kappa}B luminescence reporter system. NF-{kappa}B signaling was visualized and quantified using low resolution, intravital imaging of the whole body and high resolution, immunofluorescence microscopic imaging of the tissues. We show that NF-{kappa}B is activated in select subset of IEC with low "leaky" NF-{kappa}B activity. These unique inflammatory epithelial cells are clustered in the gut into discrete hotspots of NF-{kappa}B activity that are visible in steady state and selectively activated by systemic LPS and human TNF or luminal bacteria. The presence of inflammatory hotspots in the normal and inflamed gut might explain the patchy mucosal lesions characterizing CD and thus could have important implications for diagnosis and therapy.

immunology↗