Biology subjects

Hanamsagar, R.

Publications and source records attributed to Hanamsagar, R..

5 recordsLinked to original sources

bioRxiv2026

Scalable Generation of Universal hiPSC-Derived Vascular Progenitor Cells for Safe and Sustained Revascularization in Chronic Limb-Threatening Ischemia

BackgroundChronic limb-threatening ischemia (CLTI) is the most severe form of peripheral artery disease and can result in debilitating tissue damage, limb loss, and mortality if left untreated. Despite surgical bypass and endovascular interventions, there is high unmet need to develop novel therapies that can restore durable blood flow and rescue limb function in patients whose disease is not amenable to surgical bypass and endovascular procedures. Human induced pluripotent stem cell (hiPSC)-derived vascular progenitor cells (VPC) hold promise for addressing this unmet need, yet their clinical adoption will require a scalable and consistently high-quality cell product that can be used safely in a large number of CLTI patients. MethodsHere, we report a robust, scalable GMP-adaptable platform for generating universally immuno-compatible VPC from human leukocyte antigen (HLA) class I/II-edited hiPSCs with extensive characterization of phenotypic and functional attributes critical to address key translational gaps in developing cell-based therapies for CLTI. We have interrogated their therapeutic efficacy in multiple murine CLTI models using a combination of clinically relevant endpoints, histology, and tissue-based RNAseq analysis. ResultsWe found that VPC-treated mice exhibited significantly improved perfusion ratios and preserved limb function, reduced inflammation, and increased physiological neovascularization without pathological malformations. ConclusionsGenetic modification conferring hypoimmune status coupled with a robust differentiation process enables large scale production of an "off-the shelf" high-quality VPC product with the potential to address unmet need in CLTI patients regardless of HLA status.

cell biology↗

bioRxiv2024

An immunocompetent human kidney on-a-chip model to study renal inflammation and immune-mediated injury

Kidney damage and dysfunction is an emerging health issue worldwide resulting in high morbidity and mortality rates. Numerous renal diseases are recognized to be driven by the immune system. Despite this recognition, the development of targeted therapies has been challenging as knowledge of the underlying mechanism and complex interactions remains insufficient. Recent advancements in the field offer promising avenues for exploring the interplay between renal cells and immune cells and their role in the development of renal inflammation and diseases. This study describes the establishment of a human immunocompetent 3D in vitro co-culture model of the proximal tubule in a high-throughput microfluidic platform that can be used to study renal functionality and inflammatory processes. The model incorporated RPTEC in the top compartment and HUVECs in the bottom compartment cultured under flow and in direct contact with a collagen-I ECM gel resulting in the formation of polarized tubular structures. As an immune component, human primary monocytes of different donors were added to the lumen of the endothelium. Renal inflammation was successfully induced using complement activated serum (CAS) as evident by epithelial morphological changes, increased expression of adhesion molecules, release of pro-inflammatory cytokines, and reduced epithelial viability. Realtime migratory behavior of monocytes showed increased extravasation and migration towards the ECM and Renal compartment upon exposure to CAS with donor-to-donor differences observed. Finally, immune modulatory compounds showed efficacious inhibition of monocyte migration under inflammatory conditions in the microfluidic co-culture model. A successful co-culture model was established and can be applied to study renal functionality in health and disease but also for drug screening due to the compatibility of the platform with automation and relatively high throughput. Overall, the described proximal tubule model has high potential to fill the gap that currently exists to study renal inflammation preclinically.

immunology↗

bioRxiv2021

Cell type classification and discovery across diseases, technologies and tissues reveals conserved gene signatures and enables standardized single-cell readouts

Autoimmune diseases are a major cause of mortality1,2. Current treatments often yield severe insult to host tissue. It is hypothesized that improved "precision medicine" therapies will target pathogenic cells selectively and thus reduce or eliminate severe side effects, and potentially induce robust immune tolerance3. However, it remains challenging to systematically identify which cellular phenotypes are present in cellular ensembles. Here, we present a novel machine learning approach, Signac, which uses neural networks trained with flow-sorted gene expression data to classify cellular phenotypes in single cell RNA-sequencing data. We demonstrate that Signac accurately classified single cell RNA-sequencing data across diseases, technologies, species and tissues. Then we applied Signac to identify known and novel immune-relevant precision medicine candidate drug targets (n = 12) in rheumatoid arthritis. A full release of this workflow can be found at our GitHub repository (https://github.com/mathewchamberlain/Signac).

immunology↗

bioRxiv2020

Neonatal immune challenge induces female-specific changes in social behavior and somatostatin cell number, independent of microglial inflammatory signaling

Decreases in social behavior are a hallmark aspect of acute "sickness behavior" in response to infection. However, immune insults that occur during the perinatal period may have long-lasting consequences for adult social behavior by impacting the developmental organization of underlying neural circuits. Microglia, the resident immune cells of the central nervous system, are sensitive to immune stimulation and play a critical role in the developmental sculpting of neural circuits, making them likely mediators of this process. Here, we investigated the impact of a postnatal day (PND) 4 lipopolysaccharide (LPS) challenge on social behavior in adult mice. Somewhat surprisingly, neonatal LPS treatment decreased sociability in adult female, but not male mice. LPS-treated females also displayed reduced social interaction and social memory in a social discrimination task as compared to saline-treated females. Somatostatin (SST) interneurons within the anterior cingulate cortex (ACC) have recently been suggested to modulate a variety of social behaviors. Interestingly, the female-specific changes in social behavior observed here were accompanied by an increase in SST interneuron number in the ACC. Finally, these changes in social behavior and SST cell number do not appear to depend on microglial inflammatory signaling, because microglia-specific genetic knock-down of myeloid differentiation response protein 88 (MyD88; the removal of which prevents LPS from increasing proinflammatory cytokines such as TNF and IL-1{beta}) did not prevent these LPS-induced changes. This study provides novel evidence for enduring effects of neonatal immune activation on social behavior and SST interneurons in females, independent of microglial inflammatory signaling.

neuroscience↗

bioRxiv2019

An optimized workflow for single-cell transcriptomics and repertoire profiling of purified lymphocytes from clinical samples.

Establishing clinically relevant single-cell (SC) transcriptomic workflows from cryopreserved tissue is essential to move this emerging immune monitoring technology from the bench to the bedside. Improper sample preparation leads to detrimental cascades, resulting in loss of precious time, money and finally compromised data. There is an urgent need to establish protocols specifically designed to overcome the inevitable variations in sample quality resulting from uncontrollable factors in a clinical setting. Here, we explore sample preparation techniques relevant to a range of clinically relevant scenarios, where SC gene expression and repertoire analysis are applied to a cryopreserved sample derived from a small amount of blood, with unknown or partially known preservation history. We compare a total of ten cell-counting, viability-improvement, and lymphocyte-enrichment methods to highlight a number of unexpected findings. Trypan blue-based automated counters, typically recommended for single-cell sample quantitation, consistently overestimate viability. Advanced sample clean-up procedures significantly impact total cell yield, while only modestly increasing viability. Finally, while pre-enrichment of B cells from whole peripheral blood mononuclear cells (PBMCs) results in the most reliable BCR repertoire data, comparable T-cell enrichment strategies distort the ratio of CD4+ and CD8+ cells. Furthermore, we provide high-resolution analysis of gene expression and clonotype repertoire of different B cell subtypes. Together these observations provide both qualitative and quantitative sample preparation guidelines that increase the chances of obtaining high-quality single-cell transcriptomic and repertoire data from human PBMCs in a variety of clinical settings.

immunology↗