Biology subjects

Dandri, M.

Publications and source records attributed to Dandri, M..

8 recordsLinked to original sources

bioRxiv2025

Merkel cell polyomavirus infection and persistence modelled in skin organoids

Merkel cell polyomavirus (MCPyV) causes most Merkel cell carcinomas (MCC). The virus is one of the few known human tumor viruses, and due to its direct role in this skin cancer development, it is a bona fide model for viral tumorigenesis and tumorigenesis in general. Chronic viruses in humans such as MCPyV are highly adapted to their host and current models to study infection, persistence and pathogenesis are highly limited. We here use an induced pluripotent stem cell (iPSC)-derived hair-bearing skin organoid (SkO) system to demonstrate efficient viral infection, progression and spread of MCPyV. Using bulk-, single cell - and spatial-transcriptomics, combined with immunostaining and nucleic acid hybridization technologies, we show that MCPyV ensures persistence due to a quasi-latency state within the majority of dermal fibroblasts carry the viral genome. Further, we identify the cell type of productive infection with papillary fibroblasts and dermal sheath fibroblasts supporting viral replication and progeny production. Our high-resolution methods demonstrate that the virus in these cells evades the innate immune response, as evidenced by the efficacy of interferon-beta treatment or ruxolitinib, a JAK/STAT inhibitor, in suppressing or stimulating viral replication. We show that iPSC-derived SkOs are able to support infection and long-term persistence of the virus under conditions very similar to those found in humans. Thus, this infection model provides a robust platform for understanding and characterizing the interaction of this virus with the immune system in infection, testing treatment strategies to control reactivation and map processes involved in tumor development.

molecular biology↗

bioRxiv2024

Accessing the specific capacity of TIL-derived CD8 T-cells to suppress tumor recurrence in resectable HBV-HCC patients

BackgroundHepatocellular carcinoma represents a significant global health challenge, affecting over a million patients annually, arising mainly from chronic liver diseases, with a majority being related to viral infections. However, despite the groundbreaking clinical results of immune checkpoint blockades and adoptive cell therapies, we still face non-responders accompanied by high rebound rates after resection. Considering that the main concern is to overcome a highly specialized immunosuppressive tumor microenvironment of the individual patient, the characterization of the particular tumor microenvironment and the source of the immune cells used in ACT is of immense importance. Approved ACT therapies mainly use modified peripheral blood cells from individuals. At the same time, tumor-infiltrating lymphocytes are underrepresented even if they have garnered interest due to their potential to target tumor-specific antigens more effectively. MethodsIn this study, we employed allogenic and autologous immune cell sources for expansion and stimulation, resulting in adoptive T-cell transfer experiments determining the effector cell differentiation and the related anti-tumor effects by the possible implementation of re-stimulation. ResultsWe determined a high success rate in expanding and stimulating tumor-infiltrating lymphocytes with consistent CD8 T-cell fractions from HCC patients. To showcase the effectiveness of stimulated T-cells from different sources, we generated cell lines derived from the margin and center of an HBV-induced HCC with a highly immune-suppressive TME. We found effective immune responses supported by cell death induction, ferroptosis, proptosis and apoptosis triggered by all sources of T-cells depending on the area of derived tumor cells. ConclusionEffector T-cell fractions derived from tumor-infiltrating lymphocytes present a viable source for cell-based immune therapy combined with immune checkpoint inhibitors in HCC patients, especially after resection, to suppress rebound strategies of the parental tumor on an individual level.

immunology↗

bioRxiv2024

Patient-derived HCC cells recapitulating the transcriptomic landscape of primary HCV-related liver cancer

BackgroundThe hepatocellular carcinoma is one of the leading causes of cancer-related mortality and is characterized by high heterogeneity and subsequently adaptation by developing resistance to current treatments. In this scenario the application of individualized models is crucial to understand the potential of approved therapies. Recently, we established a series of individual cell lines derived from patients who developed HCC on different entities, serving as a platform for individual approaches. In this study, we classified the LC4 cells derived from the center region of a HCC with underlying HIV-HCV co-infection, by using deep analysis on the pathway regulation level. MethodsWe employed DEG analysis, followed by pathway analysis to characterize the preservation level of the LC4 cells and the level of adoption. Next, we classify the model, by employing healthy donor samples, commonly used HCC cell lines and global RNAseq data sets. ResultsWe showed that the LC4 cells reflect significant characteristics of the parental region, including the replication of the immuno-suppressive and the proliferative milieu. The LC4 cells exhibit a metabolic reprogramming characterized by the downregulation of drug-metabolizing CYP enzymes compared to healthy individuals, indicating a transition to alternate metabolic pathways. Moreover, we identified common Biomarkers in the parental tissue, global datasets and the LC4 cells. ConclusionWe showed that the LC4 cell line is applicable as an individual model for pre-clinical testing of treatment regimens in HCC driven research.

cancer biology↗

bioRxiv2024

Ex-vivo expansion of patient-derived PBMCs preferentially results in effector memory T-cell proliferation with restored autologous efficiency in HBV-HCC

BackgroundT-cell-based therapies achieved milestones in targeting solid tumors, such as hepatocellular carcinoma, by leveraging the cytotoxic potential of effector memory T-cells. However, a key challenge lies in the ex-vivo expansion of functional memory T-cells while simultaneously preventing over-differentiation into senescent TEMRA cells. MethodsPBMC derived from 10 HCC patients and two healthy donors were used for expansion in small bioreactors equipped with a permeable membrane for 2 weeks. During expansion, surface marker composition, cytokine and chemokine production were observed. Enriched T-cell subsets from three patients with chronic HBV infection were analysed in detail. We extracted the enriched complement of one chronically infected patient to elucidate the therapeutic potential. ResultsWe successfully expanded the effector T-cell subsets for all investigated samples and consistently enriched the cell amount over time. Subsequently, we showed that the expanded patient-derived T-cells showed functionality against autologous liver cancer-derived cells by inducing receptor and protein-mediated cell death. ConclusionWe showed the consistent ex-vivo expansion of T-cell subsets of initial patient-derived PBMCs. The enriched subsets exhibit cytotoxic functionality and shift to cytolytic TEMRA cells in an immune evasion setting in the context of chronic HBV-infected patient-derived liver cancer cells.

immunology↗

bioRxiv2023

Multiscale modeling of HBV infection integrating intra- and intercellular viral propagation for analyzing extracellular viral markers

Chronic infection of hepatitis B virus (HBV) is caused by the persistence of closed circular DNA (cccDNA) in the nucleus of infected hepatocytes. Despite available therapeutic anti-HBV agents, eliminating the cccDNA remains challenging. The quantifying and understanding dynamics of cccDNA are essential for developing effective treatment strategies and new drugs. However, it requires a liver biopsy to measure the intrahepatic cccDNA, which is basically not accepted because of the ethical aspect. We here aimed to develop a non-invasive method for quantifying cccDNA in the liver using surrogate markers present in peripheral blood. We constructed a multiscale mathematical model that explicitly incorporates both intracellular and intercellular HBV infection processes. The model, based on age-structured partial differential equations (PDEs), integrates experimental data from in vitro and in vivo investigations. By applying this model, we successfully predicted the amount and dynamics of intrahepatic cccDNA using specific viral markers in serum samples, including HBV DNA, HBsAg, HBeAg, and HBcrAg. Our study represents a significant step towards advancing the understanding of chronic HBV infection. The non-invasive quantification of cccDNA using our proposed methodology holds promise for improving clinical analyses and treatment strategies. By comprehensively describing the interactions of all components involved in HBV infection, our multiscale mathematical model provides a valuable framework for further research and the development of targeted interventions.

microbiology↗

bioRxiv2022

Prediction of elimination of intrahepatic cccDNA in hepatitis B virus-infected patients by a combination of noninvasive viral markers

Evaluation of intrahepatic covalently closed circular DNA (cccDNA) is a key for searching an elimination of hepatitis B virus (HBV) infection. HBV RNA and HBV core-related antigen have been proposed as surrogate markers for evaluating cccDNA activity, although they do not necessarily estimate the amount of cccDNA. Here, we developed a novel multiscale mathematical model describing intra- and inter-cellular viral propagation, based on the experimental quantification data in both HBV-infected cell culture and humanized mouse models. We applied it to HBV-infected patients under treatment and developed a model which can predict intracellular HBV dynamics only by use of noninvasive extracellular surrogate biomarkers. Importantly, the model prediction of the amount of cccDNA in patients over time was confirmed to be well-correlated with the liver biopsy data. Thus, our noninvasive method enables to predict the amount of cccDNA in patients and contributes to determining the treatment endpoint required for elimination of intrahepatic cccDNA.

microbiology↗

bioRxiv2022

The potent broadly neutralizing antibody VIR-3434 controls Hepatitis B and D Virus infection and reduces HBsAg in humanized mice

Background & AimsChronic hepatitis B is a major global public health problem, and coinfection with hepatitis delta virus (HDV) worsens disease outcome. Here, we describe a hepatitis B virus (HBV) surface antigen (HBsAg)-targeting monoclonal antibody (mAb) with the potential to promote functional cure of chronic hepatitis B and D to address this unmet medical need. MethodsHBsAg-specific mAbs were isolated from memory B cells of HBV vaccinated individuals. In vitro neutralization was determined against HBV and HDV enveloped with HBsAg representing eight HBV genotypes. Human liver-chimeric mice were treated twice weekly with a candidate mAb starting three weeks post HBV inoculation (spreading phase) or during stable HBV or HBV/HDV coinfection (chronic phase). ResultsFrom a panel of human anti-HBs mAbs, VIR-3434 was selected and engineered for pre-clinical development. VIR-3434 targets a putative conserved, conformational epitope within the antigenic loop of HBsAg and neutralized HBV and HDV infection with >12,000-fold higher potency than Hepatitis B Immunoglobulins in vitro. Neutralization was pan-genotypic against strains representative of HBV genotypes A-H. In the spreading phase of HBV infection in human liver-chimeric mice, a parental mAb of VIR-3434 (HBC34) prevented HBV dissemination and intrahepatic HBV RNA and cccDNA increase. In the chronic phase of HBV infection or co-infection with HDV, HBC34 treatment decreased circulating HBsAg by >1 log and HDV RNA by >2 logs. ConclusionsThis in vitro and in vivo characterization identified the potent anti-HBs mAb VIR-3434, which reduces circulating HBsAg and HBV/HDV viremia in human liver-chimeric mice. VIR-3434 is currently in clinical development for treatment of patients with chronic hepatitis B or D. Lay summaryChronic infection with hepatitis B virus places approximately 290 million individuals worldwide at risk for severe liver disease and cancer. Currently available treatments result in low rates of functional cure or require lifelong therapy that does not eliminate the risk of liver disease. We isolated and characterized a potent, human antibody that neutralizes hepatitis B and D viruses and reduces infection in a mouse model. This antibody could provide a new treatment for patients with chronic hepatitis B and D. HighlightsO_LIIdentification of a human mAb VIR-3434 that potently neutralizes HBV and HDV C_LIO_LIVIR-3434 targets a conserved, conformational epitope of the HBsAg antigenic loop C_LIO_LIVIR-3434 treatment blocks intrahepatic HBV spread in human liver-chimeric mice C_LIO_LIVIR-3434 treatment reduces circulating HBsAg and HDV RNA in co-infected mice C_LIO_LIData have enabled clinical development of VIR-3434 against chronic hepatitis B/D C_LI

microbiology↗

bioRxiv2020

SARS-CoV-2 infects carotid arteries: implications for vascular disease and organ injury in COVID-19

Stroke and central nervous system dysfunction are cardinal symptoms in critically ill corona virus disease 19 (COVID-19) patients. In an autopsy series of 32 COVID-19 patients, we investigated whether carotid arteries were infected with SARS-CoV-2 by employing genomic, virologic, histochemical and transcriptomic analyses. We show that SARS-CoV-2 productively infects and modulates vascular responses in carotid arteries. This finding has far reaching implications for the understanding and clinical treatment of COVID-19.

microbiology↗