Cell Population Level Research Articles

Elucidating siRNA Cellular Delivery Mechanism Mediated by Quaternized Starch Nanoparticles.

Starch-based nanoparticles are highly utilized in the realm of drug delivery taking advantage of their biocompatibility and biodegradability. Studies have utilized Quaternized starch (Q-starch) for small interfering RNA (siRNA) delivery, in which quaternary amines enable interaction with negatively charged siRNA, resulting in self-assembly complexation. Although reports present numerous applications, the demonstrated efficacy is nonetheless limited due to undiscovered cellular mechanistic delivery. In this study, a deep dive into Q-starch/siRNA complexes' cellular mechanism and kinetics at the cellular level is revealed using single-particle tracking and cell population level using imaging flow cytometry. Uptake studies depict the efficient cellular internalization via endocytosis while a significant fraction of complexes' intracellular fate is lysosome. Utilizing single-particle tracking, it is found that an average of 15% of cellular detected complexes escape the endosome which holds the potential for the integration in the cytoplasmatic gene silencing mechanism. Additional experimental manipulations (overcoming endosomal escape) demonstrate that the complex's disassembly is the rate-limiting step, correlating Q-starch's structure-function properties as siRNA carrier. Structure-function properties accentuating the high affinity of the interaction between Q-starch's quaternary groups and siRNA's phosphate groups that results in low release efficiency. However, low-frequency ultrasound (20kHz) application may have induced siRNA release resulting in faster gene silencing kinetics.

An in-silico approach to the dynamics of proliferation potential in stem cells and the study of different therapies in cases of ovarian dysfunction

A discrete mathematical model based on ordinary differential equations and the associated continuous model formed by a partial differential equation, which simulate the generational and temporal evolution of a stem cell population, are proposed. The model parameters are the maximum proliferation potential and the rates of mitosis, death events and telomerase activity. The mean proliferation potential at each point in time is suggested as an indicator of population aging. The model is applied on hematopoietic stem cells (HSCs), with different telomerase activity rates, in a range of variation of maximum proliferation potential in healthy individuals, to study the temporal evolution of aging. HSCs express telomerase, however not at levels that are sufficient for maintaining constant telomere length with aging [1,2]. Women with primary ovarian insufficiency (POI) are known to have low telomerase activity in granulosa cells and peripheral blood mononuclear cells [3]. Extrapolating this to hematopoietic stem cells, the mathematical model shows the differences in proliferation potential of the cell populations when telomerase expression is activated using sexual steroids, though the endogenous promoter or with gene therapy using exogenous, stronger promoters within the adeno-associated virus. In the first case, proliferation potential of cells from POI condition increases, but when adeno-associated viruses are used, the proliferation potential reaches the levels of healthy cell populations.

Racial Differences in Systemic Immune Parameters in Individuals With Lung Cancer

IntroductionRacial and ethnic disparities in the presentation and outcomes of lung cancer are widely known. To evaluate potential factors contributing to these observations, we measured systemic immune parameters in Black and White patients with lung cancer. MethodsPatients scheduled to receive cancer immunotherapy were enrolled in a multi-institutional prospective biospecimen collection registry. Clinical and demographic information were obtained from electronic medical records. Pretreatment peripheral blood samples were collected and analyzed for cytokines using a multiplex panel and for immune cell populations using mass cytometry. Differences between Black and White patients were determined and corrected for multiple comparisons. ResultsA total of 187 patients with NSCLC (Black, 19; White, 168) were included in the analysis. Compared with White patients, Black patients had greater comorbidity (median Charlson Comorbidity Index 5 versus 3; p = 0.04) and were more likely to have received previous chemotherapy (79% versus 47%; p = 0.03). Black patients had significantly lower levels of CCL23 and CCL27 and significantly higher levels of CCL8, CXCL1, CCL26, CCL25, CCL1, IL-1b, CXCL16, and IFN-γ (all p < 0.05, false discovery rate < 0.1). Black patients also exhibited greater populations of nonclassical CD16+ monocytes, NKT-like cells, CD4+ cells, CD38+ monocytes, and CD57+ gamma delta T cells (all p < 0.05). ConclusionsBlack and White patients with lung cancer exhibit several differences in immune parameters, with Black patients exhibiting greater levels of numerous proinflammatory cytokines and cell populations. The etiology and clinical significance of these differences warrant further evaluation.

Lysis of human erythrocytes due to Piezo1-dependent cytosolic calcium overload as a mechanism of circulatory removal

Hematopoietic stem cells surrender organelles during differentiation, leaving mature red blood cells (RBC) devoid of transcriptional machinery and mitochondria. The resultant absence of cellular repair capacity limits RBC circulatory longevity, and old cells are removed from circulation. The specific age-dependent alterations required for this apparently targeted removal of RBC, however, remain elusive. Here, we assessed the function of Piezo1, a stretch-activated transmembrane cation channel, within subpopulations of RBC isolated based on physical properties associated with aging. We subsequently investigated the potential role of Piezo1 in RBC removal, using pharmacological and mechanobiological approaches. Dense (old) RBC were separated from whole blood using differential density centrifugation. Tolerance of RBC to mechanical forces within the physiological range was assessed on single-cell and cell population levels. Expression and function of Piezo1 were investigated in separated RBC populations by monitoring accumulation of cytosolic Ca2+ and changes in cell morphology in response to pharmacological Piezo1 stimulation and in response to physical forces. Despite decreased Piezo1 activity with increasing cell age, tolerance to prolonged Piezo1 stimulation declined sharply in older RBC, precipitating lysis. Cell lysis was immediately preceded by an acute reversal of density. We propose a Piezo1-dependent mechanism by which RBC may be removed from circulation: Upon adherence of these RBC to other tissues, they are uniquely exposed to prolonged mechanical forces. The resultant sustained activation of Piezo1 leads to a net influx of Ca2+, overpowering the Ca2+-removal capacity of specifically old RBC, which leads to reversal of ion gradients, dysregulated cell hydration, and ultimately osmotic lysis.

Unlocking the potential of HHLA2: identifying functional immune infiltrating cells in the tumor microenvironment and predicting clinical outcomes in laryngeal squamous cell carcinoma

BackgroundHHLA2 (human endogenous retrovirus-H long terminal repeat-associating protein 2) represents a recently identified member of the B7 immune checkpoint family, characterized by limited expression in normal tissues but notable overexpression in various cancer types. Nevertheless, the precise function and interaction with immune cells remain poorly understood, particularly in laryngeal squamous cell carcinoma (LSCC). This investigation endeavored to elucidate the biological significance of HHLA2 within the tumor microenvironment of human LSCC tissues and delineate the clinical relevance and functional roles of HHLA2 in LSCC pathogenesis.MethodsThrough multiplexed immunohistochemistry analyses conducted on tissue microarrays sourced from LSCC patients (n = 72), the analysis was executed to assess the expression levels of HHLA2, density and spatial patterns of CD68+HLA-DR+CD163− (M1 macrophages), CTLA-4+CD4+FoxP3+ (CTLA-4+Treg cells), CTLA-4+CD4+FoxP3− (CTLA-4+Tcon cells), exhausted CD8+T cells, and terminally exhausted CD8+T cells in LSCC tissues. Survival analysis was conducted to evaluate the prognostic significance of HHLA2 and these immune checkpoints or immune cell populations, employing COX regression analysis to identify independent prognostic factors.ResultsKaplan–Meier (K–M) survival curves revealed a significant association between HHLA2 expression and overall survival (OS) in LSCC. Elevated levels of HHLA2 were linked to reduced patient survival, indicating its potential as a prognostic marker (HR: 3.230, 95%CI 0.9205–11.34, P = 0.0067). Notably, increased infiltration of CD68+ cells (total macrophages), STING+CD68+HLA-DR+CD163− (STING+M1 macrophages), CTLA-4+CD4+FoxP3+, CTLA-4+CD4+FoxP3−, PD-1+LAG-3+CD8+T cells, and PD-1+LAG-3+TIM-3+CD8+T cells strongly linked to poorer survival outcomes (P < 0.05). A discernible trend was observed between the levels of these immune cell populations, STING+CD68+ (STING+ total macrophages), CD68+HLA-DR+CD163−, STING+CD68+CD163+HLA-DR− (STING+M2 macrophages), PD-1+LAG-3−CD8+T cells, PD-1+TIM-3+CD8+T cells, and PD-1+LAG-3+TIM-3−CD8+T cells and prognosis. Importantly, multivariate COX analysis identified HHLA2 as an independent predictive factor for OS in LSCC patients (HR = 3.86, 95%CI 1.08–13.80, P = 0.038). This underscored the potential of HHLA2 as a critical marker for predicting patient outcomes in LSCC.ConclusionsHHLA2 emerged as a detrimental prognostic biomarker for assessing OS in LSCC patients. Relative to other immune checkpoints, HHLA2 exhibited heightened predictive efficacy for the prognosis of LSCC patients.

Defining PANoptosis: Biochemical and Mechanistic Evaluation of Innate Immune Cell Death Activation.

The innate immune system is the first line of host defense. Innate immune activation utilizes pattern recognition receptors to detect pathogens, pathogen-associated and damage-associated molecular patterns (PAMPs and DAMPs), and homeostatic alterations and drives inflammatory signaling pathways and regulated cell death. Cell death activation is critical to eliminate pathogens and aberrant or damaged cells, while excess activation can be linked to inflammation, tissue damage, and disease. Therefore, there is increasing interest in studying cell death mechanisms to understand the underlying biology and identify therapeutic strategies. However, there are significant technical challenges, as many cell death pathways share key molecules with each other, and genetic models where these cell death molecules are deleted remain the gold standard for evaluation. Furthermore, extensive crosstalk has been identified between the cell death pathways pyroptosis, apoptosis, necroptosis, and the more recently characterized PANoptosis, which is defined as a prominent, unique innate immune, lytic, and inflammatory cell death pathway initiated by innate immune sensors and driven by caspases and RIPKs through PANoptosomes. PANoptosomes are multi-protein complexes assembled by innate immune sensor(s) in response to pathogens, PAMPs, DAMPs, cytokines, and homeostatic changes that drive PANoptosis. In this article, we provide methods for molecularly defining distinct cell death pathways, including PANoptosis, using both genetic and chemical approaches through western blot, LDH assay, and microscopy readouts. This procedure allows for the assessment of cell death on the cell population and single-cell levels even without access to genetic models. Having this comprehensive workflow that is more accessible to all labs will improve our ability as a scientific community to accelerate discovery. Using these protocols will help identify new innate immune sensors that drive PANoptosis and define the molecular mechanisms and regulators involved to establish new targetsfor clinical translation. © 2024 The Author(s). Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Induction and quantification of cell death using live cell imaging Alternate Protocol 1: Quantification of cell death using LDH Alternate Protocol 2: Assessment of cell death complexes in single cells using immunofluorescence staining Basic Protocol 2: Analysis of cell death mechanisms by immunoblots (western blots).

Differences in systemic immune parameters in individuals with lung cancer according to race.

Racial and ethnic disparities in the presentation and outcomes of lung cancer are widely known. To evaluate potential factors contributing to these observations, we measured systemic immune parameters in Black and White patients with lung cancer. Patients scheduled to receive cancer immunotherapy were enrolled in a multi-institutional prospective biospecimen collection registry. Clinical and demographic information were obtained from electronic medical records. Pre-treatment peripheral blood samples were collected and analyzed for cytokines using a multiplex panel and for immune cell populations using mass cytometry. Differences between Black and White patients were determined and corrected for multiple comparisons. A total of 187 patients with non-small cell lung cancer (Black, 19; White, 168) were included in the analysis. There were no significant differences in baseline characteristics between Black and White patients. Compared to White patients, Black patients had significantly lower levels of CCL23 and CCL27, and significantly higher levels of CCL8, CXCL1, CCL26, CCL25, CCL1, IL-1 b, CXCL16, and IFN-γ (all P <0.05, FDR<0.1). Black patients also exhibited greater populations of non-classical CD16+ monocytes, NKT-like cells, CD4+ cells, CD38+ monocytes, and CD57+ gamma delta T cells (all P <0.05). Black and White patients with lung cancer exhibit several differences in immune parameters, with Black patients exhibiting greater levels of numerous pro-inflammatory cytokines and cell populations. The etiology and clinical significance of these differences warrant further evaluation.

An amphioxus neurula stage cell atlas supports a complex scenario for the emergence of vertebrate head mesoderm

The emergence of new structures can often be linked to the evolution of novel cell types that follows the rewiring of developmental gene regulatory subnetworks. Vertebrates are characterized by a complex body plan compared to the other chordate clades and the question remains of whether and how the emergence of vertebrate morphological innovations can be related to the appearance of new embryonic cell populations. We previously proposed, by studying mesoderm development in the cephalochordate amphioxus, a scenario for the evolution of the vertebrate head mesoderm. To further test this scenario at the cell population level, we used scRNA-seq to construct a cell atlas of the amphioxus neurula, stage at which the main mesodermal compartments are specified. Our data allowed us to validate the presence of a prechordal-plate like territory in amphioxus. Additionally, the transcriptomic profile of somite cell populations supports the homology between specific territories of amphioxus somites and vertebrate cranial/pharyngeal and lateral plate mesoderm. Finally, our work provides evidence that the appearance of the specific mesodermal structures of the vertebrate head was associated to both segregation of pre-existing cell populations, and co-option of new genes for the control of myogenesis.

Role of inflammatory populations and their intermediates in post-ischemic adverse remodeling in rat model of myocardial infarction

Abstract Funding Acknowledgements Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Junta de Andalucía- Fondos FEDER Background Compelling evidence demonstrated the critical role of inflammation in ventricular adverse remodeling after acute myocardial infarction. However, it remains unclear how inflammatory cell population and their intermediates participate in the progress of the disease. Purpose This study aims to elucidate the role of inflammatory population in cardiac remodeling after myocardial infarction in a rat model, focusing on their role in fibrosis. Methods We used a surgical procedure by transient ligation of the left descendant coronary artery, to evoke ischemia-reperfusion (I/R) in rats. We performed FACS analysis to evaluate counts of neutrophils and two monocytes’ subsets: CD43lowHis48high (classical monocytes), and CD43highHis48low (non-classical monocytes), which are the most pro-inflammatory subset in peripheral blood. Subsequently, we performed immunofluorescence to detect pro-inflammatory M1 and M2 macrophages (CD68+ and CD163+) in the rat infarcted myocardium. Moreover, we sorted the two monocyte subsets and performed genes and microRNAs Array. Results FACS analysis of neutrophils and monocytes subsets showed an increased level of these cells in the rat model of myocardial infarction, one week after the post-ischemic event. In parallel, the infiltration of M1 macrophages was increased in the myocardium until 1 week after surgery, indicating a long extravasation of inflammatory cells after the ischemic event. Moreover, co-culture of fibroblasts and cardiomyocytes with intermediates released by inflammatory cells subjected to I/R increased the expression of fibrotic and apoptotic genes. In addition, the analysis of genes’ Array by GSEA indicated that CD43highHis48low monocytes had an enrichment score in pathways associated with angiogenesis, fibrosis and inflammation, while CD43lowHis48high population exhibited an enrichment in cytokines and inflammation, apoptosis and fibrosis. Finally, we found significant overexpression of microRNAs, for instance, miR-27a-3p, miR-29b-3p, miR-30e-5p and miR-194-5p in CD43highHis48low 24h after the I/R procedure. Those miRNAs are predicted to modulate pro-fibrotic genes. Conclusions The level of inflammatory cell populations is increased in I/R rat model. Moreover, these cells infiltrate in the myocardium likely to change the transcriptome of resident cells towards a pro-apoptotic and pro-fibrotic phenotype.

Microheterogeneity in the Kinetics and Sex-Specific Response to Type I IFN.

The response to type I IFNs involves the rapid induction of prototypical IFN signature genes (ISGs). It is not known whether the tightly controlled ISG expression observed at the cell population level correctly represents the coherent responses of individual cells or whether it masks some heterogeneity in gene modules and/or responding cells. We performed a time-resolved single-cell analysis of the first 3 h after invivo IFN stimulation in macrophages and CD4+ T and B lymphocytes from mice. All ISGs were generally induced in concert, with no clear cluster of faster- or slower-responding ISGs. Response kinetics differed between cell types: mostly homogeneous for macrophages, but with far more kinetic diversity among B and T lymphocytes, which included a distinct subset of nonresponsive cells. Velocity analysis confirmed the differences between macrophages in which the response progressed throughout the full 3 h, versus B and T lymphocytes in which it was rapidly curtailed by negative feedback and revealed differences in transcription rates between the lineages. In all cell types, female cells responded faster than their male counterparts. The ISG response thus seems to proceed as a homogeneous gene block, but with kinetics that vary between immune cell types and with sex differences that might underlie differential outcomes of viral infections.

A previously under-recognized role of CXCL12 in endogenous thymic regeneration

Abstract The thymus is a primary lymphoid organ for T cell development. Sensitive to stress, it undergoes acute involution in response to cytotoxic stimuli, e.g., cytoablative chemotherapy. Thus, establishing regeneration strategies to restore thymic function is vital for pediatric cancer and transplantation patients receiving such treatments. However, lack of insight for detailed mechanisms of thymic repair has impeded progress towards supporting thymic function in these patients. We developed a mouse model of cyclophosphamide-induced thymic involution, with detailed regeneration kinetics at cell population (flow cytometry) and microanatomical (digital pathology) levels. We found consistent defects of early thymocyte progenitor (ETP) seeding and trafficking during endogenous thymic repair. Single cell ATACseq analysis revealed perturbations in chromatin accessibility of the thymocyte-homing chemokine CXCL12 in various stromal cell subsets, including early developmental stages of cortical thymic epithelial cells (cTEClo) and endothelial cells, suggesting structural adaptations to accommodate ETP trafficking during thymic repair. We currently employ CXCL12 conditional ablation in cTEClo and pharmacological suppression using specific CXCR4 antagonists, to highlight the unreported role of CXCL12/CXCR4 axis in endogenous thymic repair. Together, our efforts shed novel mechanistic insights on the structural and functional adaptations of thymic stromal cells after cytotoxic chemotherapy.

Abstract 1423: Harnessing the gut microbiome to modulate immune checkpoint blockade response in triple-negative breast cancer

Abstract Triple-negative breast cancer (TNBC) is one of the most aggressive subtypes of breast cancer. The discovery that this subtype has the highest levels of tumor-infiltrating immune cells and programmed death ligand 1 (PD-L1) expression in the tumor microenvironment (TME) has propelled the use of anti-PD-1 immune checkpoint blockade (ICB) therapy, in combination with chemotherapy, as a treatment for TNBC patients. This has advantageously impacted TNBC patient outcomes such as survival, yet there remains a need to improve patient response to ICB therapies. The gut microbiome, in particular, increased abundance of Akkermansia muciniphila was associated with ICB therapy response in other cancer types. A. muciniphila can degrade mucins and produce short-chain fatty acid (SCFA) metabolites. Therefore, we investigated the interplay between A. muciniphila, SCFAs, and ICB therapy efficacy in TNBC models. As diet is the main modifier of the gut microbiome, we first investigated diet-gut microbiome interactions on ICB efficacy. Using the EO771 syngeneic murine model of TNBC, female C57BL/6 tumor-bearing mice consuming a low-fat control, or high-fat Western, or Mediterranean diet, were treated with 3 doses of 200µg of IgG or anti-PD-L1 antibodies and tumor progression was monitored. To assess changes in tumoral immune cell populations, end-of-study tumor tissue was used for immunohistochemistry (IHC). To evaluate modulation on the gut microbiome, metagenomic sequencing was performed on DNA isolated from fecal samples collected at the end-of-study, and targeted SCFA metabolomic analysis was performed on plasma collected at the study endpoint. Results show mice consuming a Mediterranean diet treated with anti-PD-L1 had significant increases in the abundance of gut A. muciniphila and plasma SCFAs, as well as significantly reduced primary tumor volume and increased immune cell activity within the TME. To then investigate if direct supplementation of A. muciniphila or SCFAs could enhance ICB efficacy, EO771 tumor-bearing mice were treated with 3 doses of 200µg of IgG, anti-PD-L1 or anti-PD-1 antibodies with a subset of mice stratified to also receive A. muciniphila or exogenoussupplementation of SCFAs. Tumor progression was measured and changes in tumoral immune cell populations were assessed with end-of-study tumor tissue prepared for flow cytometry and IHC. Results show mice supplemented with A. muciniphila and treated with anti-PD-L1 therapy demonstrated response to treatment, with a significant reduction in tumor volume as well as increased levels of immune cell populations in the TME. Mice supplemented with SCFAs and treated with a combination of anti-PD-1 and chemotherapy demonstrated enhanced response to treatment, with a significant reduction in tumor volume. In conclusion, data from our lab suggest that increased levels of gut A. muciniphila and SCFAs drive ICB efficacy in TNBC. Citation Format: Kenysha YJ. Clear, Adam S. Wilson, Elizabeth R. Stirling, Yu-Ting Tsai, Valerie Payne, David R. Soto-Pantoja, Katherine L. Cook. Harnessing the gut microbiome to modulate immune checkpoint blockade response in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1423.

“Patchiness” in mechanical stiffness across a tumor as an early-stage marker for malignancy

Mechanical phenotyping of tumors, either at an individual cell level or tumor cell population level is gaining traction as a diagnostic tool. However, the extent of diagnostic and prognostic information that can be gained through these measurements is still unclear. In this work, we focus on the heterogeneity in mechanical properties of cells obtained from a single source such as a tissue or tumor as a potential novel biomarker. We believe that this heterogeneity is a conventionally overlooked source of information in mechanical phenotyping data. We use mechanics-based in-silico models of cell-cell interactions and cell population dynamics within 3D environments to probe how heterogeneity in cell mechanics drives tissue and tumor dynamics. Our simulations show that the initial heterogeneity in the mechanical properties of individual cells and the arrangement of these heterogenous sub-populations within the environment can dictate overall cell population dynamics and cause a shift towards the growth of malignant cell phenotypes within healthy tissue environments. The overall heterogeneity in the cellular mechanotype and their spatial distributions is quantified by a “patchiness” index, which is the ratio of the global to local heterogeneity in cell populations. We observe that there exists a threshold value of the patchiness index beyond which an overall healthy population of cells will show a steady shift towards a more malignant phenotype. Based on these results, we propose that the “patchiness” of a tumor or tissue sample, can be an early indicator for malignant transformation and cancer occurrence in benign tumors or healthy tissues. Additionally, we suggest that tissue patchiness, measured either by biochemical or biophysical markers, can become an important metric in predicting tissue health and disease likelihood just as landscape patchiness is an important metric in ecology.

S100A8-enriched microglia populate the brain of tau-seeded and accelerated aging mice.

Long considered to fluctuate between pro- and anti-inflammatory states, it has now become evident that microglia occupy a variegated phenotypic landscape with relevance to aging and neurodegeneration. However, whether specific microglial subsets converge in or contribute to both processes that eventually affect brain function is less clear. To investigate this, we analyzed microglial heterogeneity in a tauopathy mouse model (K18-seeded P301L) and an accelerated aging model (Senescence-Accelerated Mouse-Prone 8, SAMP8) using cellular indexing of transcriptomes and epitopes by sequencing. We found that widespread tau pathology in K18-seeded P301L mice caused a significant change in the number and morphology of microglia, but only a mild overrepresentation of disease-associated microglia. At the cell population-level, we observed a marked upregulation of the calprotectin-encoding genes S100a8 and S100a9. In 9-month-old SAMP8 mice, we identified a unique microglial subpopulation that showed partial similarity with the disease-associated microglia phenotype and was additionally characterized by a high expression of the same calprotectin gene set. Immunostaining for S100A8 revealed that this population was enriched in the hippocampus, correlating with the cognitive impairment observed in this model. However, incomplete colocalization between their residence and markers of neuronal loss suggests regional specificity. Importantly, S100A8-positive microglia were also retrieved in brain biopsies of human AD and tauopathy patients as well as in a biopsy of an aged individual without reported pathology. Thus, the emergence of S100A8-positive microglia portrays a conspicuous commonality between accelerated aging and tauopathy progression, which may have relevance for ensuing brain dysfunction.

Effects of cannabidiol in post-stroke mood disorders in neonatal rats.

Neonatal rats can manifest post-stroke mood disorders (PSMD) following middle cerebral artery occlusion (MCAO). We investigated whether cannabidiol (CBD) neuroprotection, previously demonstrated in neonatal rats after MCAO, includes prevention of PSMD development. Seven-day-old Wistar rats (P7) underwent MCAO and received either vehicle or 5 mg/kg CBD treatment. Brain damage was quantified by MRI, and neurobehavioral and histological (TUNEL) studies were performed at P14 and P37. PSMD were assessed using the tail suspension test, forced swimming test, and open field tests. The dopaminergic system was evaluated by quantifying dopaminergic neurons (TH+) in the Ventral Tegmental Area (VTA), measuring brain dopamine (DA) concentration and DA transporter expression, and assessing the expression and function D2 receptors (D2R) through [35S]GTPγS binding. Animals without MCAO served as controls. CBD reduced MCAO-induced brain damage and improved motor performance. At P14, MCAO induced depressive-like behavior, characterized by reduced TH+ cell population and DA levels, which CBD did not prevent. However, CBD ameliorated hyperactivity observed at P37, preventing increased DA concentration by restoring D2R function. These findings confirm the development of PSMD following MCAO in neonatal rats and highlight CBD as a neuroprotective agent capable of long-term functional normalization of the dopaminergic system post-MCAO. MCAO in neonatal rats led to post-stroke mood disorders consisting in a depression-like picture in the medium term evolving towards long-term hyperactivity, associated with an alteration of the dopaminergic system. The administration of CBD after MCAO did not prevent the development of depressive-like behavior, but reduced long-term hyperactivity, normalizing dopamine receptor function. These data point to the importance of considering the development of depression-like symptoms after neonatal stroke, a well-known complication after stroke in adults. Our work confirms the interest of CBD as a possible treatment for neonatal stroke.

Trajectory inference across multiple conditions with condiments

In single-cell RNA sequencing (scRNA-Seq), gene expression is assessed individually for each cell, allowing the investigation of developmental processes, such as embryogenesis and cellular differentiation and regeneration, at unprecedented resolution. In such dynamic biological systems, cellular states form a continuum, e.g., for the differentiation of stem cells into mature cell types. This process is often represented via a trajectory in a reduced-dimensional representation of the scRNA-Seq dataset. While many methods have been suggested for trajectory inference, it is often unclear how to handle multiple biological groups or conditions, e.g., inferring and comparing the differentiation trajectories of wild-type and knock-out stem cell populations. In this manuscript, we present condiments, a method for the inference and downstream interpretation of cell trajectories across multiple conditions. Our framework allows the interpretation of differences between conditions at the trajectory, cell population, and gene expression levels. We start by integrating datasets from multiple conditions into a single trajectory. By comparing the cell’s conditions along the trajectory’s path, we can detect large-scale changes, indicative of differential progression or fate selection. We also demonstrate how to detect subtler changes by finding genes that exhibit different behaviors between these conditions along a differentiation path.

TRIB3 as a biomarker of gastric cancer cell sensitivity to chemotherapeutic agents running title: A protective role of TRIB3 on chemotherapy.

Understanding the role of TRIB3 in cellular chemotherapy responsiveness and survival could facilitate its development as a prognostic marker that could be used to improve chemotherapeutic efficiency against specific tumors. Therefore, the role of TRIB3 to reflect the cytotoxic abilities of chemotherapeutic agents was clarified in the tested gastric cancer cell lines. We have comprehensively investigated the protein expression of TRIB3 in three gastric cancer cell lines AGS, TMK-1, and MKN-45 cells treated with the anticancer drugs, 5-fluorouracil, cisplatin, and docetaxel. The Cell Count kit-8 was used to evaluate cell viability. Immunoblotting was performed to assay protein levels after drug treatment. Flow cytometry was carried out to evaluate the levels of sub-G1 cell population. Treatment of the tested gastric cancer cell lines dose-dependently decreased cell viability and protein levels of TRIB3 while increasing apoptosis. Overexpression of TRIB3 protects MKN-45 cells from endoplasmic reticulum stress-induced apoptosis but does not influence the induction of autophagy by anticancer drugs. In addition, overexpression of TRIB3 also rescued paroxetine-induced apoptosis and endoplasmic reticulum stress. Our previous and present results indicate that TRIB3 can protect gastric cancer cells against anticancer drug treatment and that downregulating TRIB3 may increase these cells' sensitivity to anticancer drugs. We thus suggest that the capability of anticancer drugs to downregulate TRIB3 can indicate tumors' potential susceptibility to these drugs.

Cell Level- Modeling of Aging and Rejuvenation

Understanding processes related to human aging and rejuvenation relies on experimental data and advanced models operating at different levels. There are several existing conceptual and specific modeling approaches. However, one of the existing tasks is compiling generic models linking properties at cell and cell-element levels to properties at systemic levels - tissue, organ, and whole body. One of the critical issues in the relevant models is the enormity of interacting components at the cell and sub-cell levels needed to represent the properties of high-level systems properly. This paper describes a promising approach to modeling and simulation at the cell population level for studying aging and rejuvenation. It also presents initial conclusions formulated based on the results of modeling and experiments coupled to it. The model is based on the concepts of the proliferation niche and homeostatic cell number stabilization in the cell population through the associated action of proliferation and apoptosis. Importantly, we address the issue of defining “aging” and “rejuvenation” for cell populations containing large numbers of cells of different ages. It is possible to demonstrate that homeostatic regulation can be performed by maintaining the concentration of a single regulatory substance. Predictions and simulations of the proposed model are compared to data from existing publications and experiments specifically conducted to validate the model. Currently, none of the available data contradicts the modeling results at the proposed level of detail. However, an inadequate number of elements and the employed statistical approach further limit progress in such modeling. Expanding the proposed method to include a realistic number of features representing human tissues, organs, and body and to allow for proper modeling of aging and rejuvenation processes requires more advanced modeling techniques.

A Peripheral Blood Signature of Increased Th1 and Myeloid Cells Combined with Serum Inflammatory Mediators Is Associated with Response to Abatacept in Rheumatoid Arthritis Patients.

Abatacept (CTLA4-Ig)-a monoclonal antibody which restricts T cell activation-is an effective treatment for rheumatoid arthritis (RA). Nevertheless, only 50% of RA patients attain clinical responses, while predictors of response are rather limited. Herein, we aimed to investigate for early biomarkers of response to abatacept, based on a detailed immunological profiling of peripheral blood (PB) cells and serum proteins. We applied flow cytometry and proteomics analysis on PB immune cells and serum respectively, of RA patients starting abatacept as the first biologic agent. After 6 months of treatment, 34.5% of patients attained response. At baseline, Th1 and FoxP3+ T cell populations were positively correlated with tender joint counts (p-value = 0.047 and p-value = 0.022, respectively). Upon treatment, CTLA4-Ig effectively reduced the percentages of Th1 and Th17 only in responders (p-value = 0.0277 and p-value = 0.0042, respectively). Notably, baseline levels of Th1 and myeloid cell populations were significantly increased in PB of responders compared to non-responders (p-value = 0.009 and p-value = 0.03, respectively). Proteomics analysis revealed that several inflammatory mediators were present in serum of responders before therapy initiation and strikingly 10 amongst 303 serum proteins were associated with clinical responses. Finally, a composite index based on selected baseline cellular and proteomics' analysis could predict response to abatacept with a high sensitivity (90%) and specificity (88.24%).

H2-K1 on MLL-AF9 Leukemia Cells Facilitates the Escape of NK Cell-Mediated Immune Surveillance

Acute myeloid leukemia (AML) is the most common form of acute leukemia in adults, and prognosis is poor; 5-year survival approximately 30%. Recently, there is an emerging recognition of the innate immune system, in particular Natural killer (NK) cells and macrophages, for immune surveillance against AML, but the mechanistic basis for this is mostly unknow. Identifying how AML cells escape immune surveillance by NK cells may translate into new treatment opportunities for AML patients. To identify new therapeutic opportunities, we recently performed an in vivo CRISPR/Cas9 screen targeting 961 cell surface genes using the MLL-AF9 AML mouse model. One of the top leukemia stem cell dependencies in the bone marrow niche was H2-K1, an ortholog of human HLA-A, a classical MHC class-I molecule. In validation experiments, we observed a seven-fold depletion (p&amp;lt;0.001) of H2-K1 sgRNA-expressing c-Kit +Cas9 + leukemia cells in the bone marrow. In contrast, genetic disruption of H2-K1 did not impact the growth and survival of MLL-AF9 leukemia cells in culture. Given the known suppressive role of MHC class-I molecules for immune cells, we speculated that H2-K1 mayprovide inhibitory signals that counteract immune-surveillance mechanisms in the bone marrow niche. To test this hypothesis, we depleted NK cells and macrophages prior to transplantation of the c-Kit + MLL-AF9 leukemia cells. Macrophage depletion by clodronate liposomes did not affect the in vivo expansion of H2-K1 sgRNA-expressing leukemia cells demonstrating that macrophages were not suppressed by H2-K1 on the leukemia cells. In contrast, NK1.1 antibody-mediated depletion of NK cells fully rescued the depletion of H2-K1 sgRNA-expressing leukemia cells in vivo. These findings suggest that H2-K1 expression on MLL-AF9 leukemia cells inhibits NK cells in this model. Consistent with these findings, H2-K1 knockdown in leukemia cells triggered a two-fold increase of INFγ production (p&amp;lt;0.01) in the NK cells, accompanied by augmented apoptosis of the leukemia cells (p&amp;lt;0.01). Given that NK cells have been shown to be dysfunctional in AML patients, we next explored whether leukemia development affects NK cell maturation. The expansion of leukemia cells in the mice skewed NK cells towards a M1 (CD27 +CD11b -) state and decreased the level of the more cytotoxic M2 (CD27 +CD11b +) and M3 (CD27 -CD11b +) populations. H2-K1 disruption in the leukemic cells restored the level of M2 and M3 NK cell population in the bone marrow. Notably, restoration of matured NK cell populations was accompanied by an increased expression of NKG2D, an activating receptor, indicating a more cytotoxic state of the NK cells. In line with these findings, ablation of H2-K1 in leukemia cells induced JAK/STAT and NF-κβ signaling in the NK cells. Taken together, our study identifies that H2-K1 on MLL-AF9 leukemia stem cells facilitates immune evasion by suppressing NK cells. H2-K1 alters the maturation and activation of NK cells in the bone marrow niche. These findings increase our understanding of how leukemia cells escape immune surveillance and suggest that the identification of corresponding mechanisms in human AML could pave the way for new therapies that boost the endogenous NK cells by restoring immune surveillance mechanisms.