Biology subjects

Lungjangwa, T.

Publications and source records attributed to Lungjangwa, T..

5 recordsLinked to original sources

bioRxiv2025

Feeder-free generation of functional dendritic cells from human pluripotent stem cells

The scarcity of primary conventional dendritic cells (cDCs) and the limited effectiveness of monocyte-derived dendritic cells (moDCs) have long hindered progress in human dendritic cell research and immunotherapy. We developed a feeder-free differentiation platform that generates CD1c+CD141+ hPSC-cDCs phenotypically aligned with CD141+ tissue-resident cDC2 subsets found in human tissues. We further optimized the differentiation process using a Design-of-Experiments framework to refine cytokine and serum conditions, enhancing differentiation efficiency while reducing cytokine demand. These hPSC-cDCs exhibit efficient antigen uptake, defined cytokine responses, and robust priming of antigen-specific CD8+ T cell proliferation and effector differentiation, outperforming moDCs in direct comparison. Together, this work establishes a robust, and generalizable platform for mechanistic studies and translational development of dendritic cell-based vaccines and standardized ex vivo T cell expansion.

immunology↗

bioRxiv2025

Systematic characterization of existing and novel inducible transgenic systems in human pluripotent stem cells after prolonged differentiation

The ability to control transgene expression both temporally and quantitatively in human-relevant cells and tissues is a cornerstone of biomedical research. Additionally, precise transgene control is crucial for optimizing human cell-based gene therapies. Human pluripotent stem cells (hPSCs) have facilitated major advances in disease modeling and the potential for regenerative medicine. Still, they are significantly limited by the lack of inducible transgenic systems that avoid silencing but maintain robust inducibility after differentiation to defined cell lineages. Here we systematically characterize the leakiness, inducibility, and tunability of multiple existing and novel transgenic systems in hPSCs and differentiated macrophages and microglia. Notably, we report the application of a small molecule-mediated splicing switch (Xon) that allows for tunable transgene expression both before and after differentiation, without the large protein tags required for current state-of-the-art degron-based methods. We use Xon to achieve tight control of reporter genes, overexpression of multiple neurodegeneration-associated genes, and Cas9-mediated genome editing. We also characterize the current limitations of this system and describe approaches that can alleviate some of these limitations. By assessing multiple transgenic systems whose inducibility spans the transcriptional, post-transcriptional, and post-translational levels, we highlight and improve upon a major technical challenge that hinders basic, translational, and clinical research in physiological human-based systems.

bioengineering↗

bioRxiv2025

Oxidative Stress and Interferon Signaling Drive Differential Pathogenesis of Ancestral and Contemporary Zika Viruses in Human Cerebral Organoids

Neurotropic Zika viruses (ZIKV) cause serious human disease with pandemic potential. Pathogenesis severities resulting from Asian/American versus African ZIKV lineage infections range from mild to severe, respectively; however, mechanisms underlying differential ZIKV pathogenesis remain unclear, as do effective therapeutic strategies. The limitations of mechanistic understanding are due in part to the challenges of comparing data generated in disparate experimental models, as well as approaches that did not test both ancestral and contemporary ZIKV infections. The goal of this work was to define differential pathogenesis mechanisms among ancestral and contemporary ZIKVs by direct infection comparisons using a relevant human stem cell-derived cerebral organoid experimental model. While Asian/American ZIKV lineage infections enhanced antiviral and interferon gene expression responses that correlated with viral RNA clearance from organoid ventricles, ancestral African lineage ZIKV infections enhanced apoptotic and stress response signaling that correlated with diminished STAT2 signaling protein levels, ongoing ZIKV replication, and production of damaging reactive oxygen species (ROS). We discovered that, surprisingly, severe ancestral Zika virus pathogenesis was dramatically reduced by Trolox, a hydroxyl radical scavenger antioxidant, thereby confirming ROS imbalance as a major pathogenesis driver. These results demonstrate that ZIKV lineage infections and pathogenesis are differentiated by their signaling responses and suggest that preventing or controlling hydroxyl radical imbalance may offer therapeutic benefits to address microcephaly and Congenital Zika Virus Syndrome. One Sentence SummaryDifferential signal transduction responses to lineage-specific Zika virus infections cause reduction-oxidation imbalance-mediated pathogenesis that is blocked by Trolox, an antioxidant.

microbiology↗

bioRxiv2024

Pharmacological inhibition of Fms-like kinase 3 (FLT3) promotes neuronal maturation and suppresses seizure in a mouse model

Fms-like tyrosine kinase 3 (FLT3) is a receptor tyrosine kinase predominantly expressed in blood and brain cells. While the FLT3 signaling pathway has been extensively studied in blood cell development and leukemia, its role in the brain remains largely unexplored. Through our groups previous high-throughput drug screening work unexpectedly found that several small molecule FLT3 inhibitors (FLT3i), including KW-2449 and Sunitinib, enhance expression of the gene encoding chloride transporter KCC2 in neurons. KCC2 is crucial for brain development and function, and its dysregulation is linked to many brain diseases. These findings suggest previously unrecognized roles of FLT3 signaling in brain health and disease that have yet to be systematically studied. In this study, we utilized a functional genomics approach to investigate the transcriptomic changes induced by pharmacological inhibition of the FLT3 pathway in brain cells, including cultured primary mouse neurons, a human stem cell-derived neuronal model of Rett syndrome (RTT), and human stem cell-derived microglia cultures. Our results show that treating human or mouse neurons with FLT3i drugs significantly upregulates genes crucial for brain development while downregulating genes linked to neuroinflammation. In contrast, FLT3i treatment of human microglia, which do not express FLT3, has no effect on their gene expression, highlighting the cell type-specific roles of FLT3 signaling in the brain. To further understand how FLT3 signaling regulates the expression of neuronal maturation genes such as KCC2, we conducted a curated CRISPR screen that identified a number of transcription factors involved in FLT3i-mediated KCC2 activation in neurons. The mRNA and protein levels of several neurodevelopmental disorder (NDD) risk genes are significantly upregulated in FLT3i-treated neurons, indicating potential therapeutic applications of FLT3i in rescuing underexpression and/or haploinsufficiency of disease-associated genes. In our in vivo studies, we evaluated the efficacy of the FLT3i drug KW-2449 in mice, demonstrating that it can effectively cross the blood-brain barrier, induce KCC2 protein expression for up to 24 hours after a single injection, and reduces seizure activity in a chemoconvulsant-induced mouse model of temporal lobe epilepsy. Collectively, our findings uncover previously unrecognized roles of neuron-specific FLT3 signaling in promoting neuronal maturation and reducing neuroinflammation. These results suggest that FLT3 kinase signaling regulates a transcriptional program vital for brain development and function, position it as a promising therapeutic target for NDD treatment.

neuroscience↗

bioRxiv2023

SARS-CoV-2 infection of human pluripotent stem cell-derived vascular cells reveals smooth muscle cells as key mediators of vascular pathology during infection

Although respiratory symptoms are the most prevalent disease manifestation of infection by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), nearly 20% of hospitalized patients are at risk for thromboembolic events. This prothrombotic state is considered a key factor in the increased risk of stroke, which is observed clinically during both acute infection and long after symptoms clear. Here we develop a model of SARS-CoV-2 infection using human-induced pluripotent stem cell-derived endothelial cells (ECs), pericytes (PCs), and smooth muscle cells (SMCs) to recapitulate the vascular pathology associated with SARS-CoV-2 exposure. Our results demonstrate that perivascular cells, particularly SMCs, are a susceptible vascular target for SARS-CoV-2 infection. Utilizing RNA sequencing, we characterize the transcriptomic changes accompanying SARS-CoV-2 infection of SMCs, PCs, and ECs. We observe that infected SMCs shift to a pro-inflammatory state and increase the expression of key mediators of the coagulation cascade. Further, we show human ECs exposed to the secretome of infected SMCs produce hemostatic factors that contribute to vascular dysfunction, despite not being susceptible to direct infection. The findings here recapitulate observations from patient sera in human COVID-19 patients and provide mechanistic insight into the unique vascular implications of SARS-CoV-2 infection at a cellular level.

microbiology↗