Fluorescence-activated Cell Sorting Analysis Research Articles

Lactiplantibacillus plantarum inhibited the growth of primary liver cancer by inducing early apoptosis and senescence, in vitro

Primary liver cancer (PLC), comprising hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA), is a severe form of cancer associated with a high mortality and morbidity rate and increasing incidence worldwide. Current treatment options are limited and chemotherapeutics demonstrate strong side effects. New therapies are highly required. Lactobacilli represent the most diverse lactic acid-producing bacteria group and a prominent example of probiotics. Several studies have highlighted the anticancer efficacy of probiotics, especially of Lactiplantibacillus plantarum. However, there are limited studies on its activity on two PLC types, hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). This study evaluated the inhibitory mechanism and properties of L. plantarum ONU 12 (Lp 12) and L. plantarum ONU 355 (Lp 355), isolated from grapes in Ukraine and France, in murine PLC cell lines, in vitro. Strain Lacticaseibacillus casei ATCC 393 (Lc 393) has been taken for a direct comparison, as the most studied probiotic strain. The three Lactobacillus species were used in three forms: as live and heat-killed suspensions, and as sonicated extracts, and tested either as a monotherapy or in combination with standard chemotherapeutics (sorafenib for HCC and gemcitabine for CCA). Cell proliferation and viability were assessed via crystal violet staining assay and cell counting kit-8 assay. The induction of senescence was investigated by senescence-associated β-galactosidase assay. Fluorescence-activated cell sorting analysis was used to determine the apoptotic mechanism behind the inhibitory property of lactobacilli. The results showed that the live suspensions and sonicated extracts of Lp 12, Lp 355, and Lc 393 demonstrated inhibitory properties in CCA and HCC cells after 48 h of incubation. In combinations with standard chemotherapeutics, lactobacilli treatments have shown strong synergistic effects. The combination therapy allowed to reduce the chemotherapeutic doses of gemcitabine from 50 μM to 0.1 and 0.05 μM and sorafenib from 13.8 μM to 6.9 and 3.45 μM. Successful treatment regimes induced early apoptosis and cellular senescence in PLC, as the mechanism of inhibition. Heat-killed suspensions showed no inhibitory effect in none of the cell lines. Both strains, Lp 12 and Lp 355, showed successful results and need further testing in vivo, using autochthonous HCC and CCA models.

CNSC-14. GLIOBLASTOMA MULTIFORME TUMOR VOLUME AND PERSISTENCE OF CHIMERIC ANTIGEN RECEPTOR T CELLS FOLLOWING TREATMENT

Abstract Glioblastoma Multiforme (GBM) is one of the most common and aggressive high-grade primary brain tumors that arises from the glial cells of the central nervous system and occurs most often in the frontal and temporal lobes. Despite current treatment options, long-term prognosis of GBM remains low with no significant improvement rates. Chimeric antigen receptor (CAR)-expressing T cells target the B cell marker CD19 and have shown increased efficacy in B cell lymphomas, and lymphoblastic leukemias suggesting benefits in GBM. This study aims to quantify the persistence of CAR-T cells in the context of GBM tumor volume following neurosurgical debulking procedure. A radiology software known as the mint Lesion was utilized to provide Tumor Response Assessment by Criteria (TRAC) reports that consist of volumetric measurements of the tumor lesions (target enhancing lesions, non-target enhancing lesions, and non-target non-enhancing lesions). Fluorescence-activated cell sorting (FACS) analysis takes a sample mixture of cells and sorts them into different populations based on specific biomarkers and characteristics. B7-H3 CAR-T cell persistence was increased in patients with a larger post-surgical tumor volume (3.04% Subject 001 with 2438 mm² volume and 2.38% Subject 003 with 224 mm² tumor volume). However, the number of CAR-T cells per 1 mm² was significantly reduced in patients with a larger post-surgical tumor volume (0.0012 cells/mm² Subject 001 and 0.010 cells/mm² Subject 003). This study shows that although there is an overall increased CAR-T cell persistence for a larger tumor volume, the number of CAR-T cells per 1 mm² is significantly smaller for larger tumor volumes, while illustrating that a larger post-surgical tumor bulk volume is correlated with an increased CAR-T cell persistence within 1-week post-infusion. These findings provide novel information and complement other correlative studies as part of the Phase 1 interventional clinical trial for glioblastoma patients.

Comparison of Different Keratinocyte Cell Line Models for Analysis of NLRP1 Inflammasome Activation

The NLRP1 (nucleotide-binding domain, leucine-rich-containing family, pyrin domain-containing-1) inflammasome is the most important inflammasome in human keratinocytes. It plays a crucial role in regulating innate immunity in the skin. This study aimed to evaluate NLRP1 inflammasome activation and the corresponding levels of detection in different keratinocyte cell lines to identify a suitable in vitro model for analyzing inflammasome activation in keratinocytes. We compared NLRP1 inflammasome activation, expression, and cell death among primary keratinocytes and immortalized keratinocyte cell lines HaCaT, HaSKpw, and SVTERT upon stimulation with ultraviolet B (UVB) irradiation or talabostat. The effects of both NLRP1 inducers on cell death and the modification of NLRP1 molecules were examined using fluorescence-activated cell sorting analysis, Western blotting, and an enzyme-linked immunosorbent assay. The key inflammasome components had varied expression levels among the keratinocyte cell models, with the highest expression observed in primary keratinocytes. Moreover, our data showed that both UVB and talabostat triggered cell death, and NLRP1 inflammasome activation was readily detected in primary keratinocytes but not in the analyzed immortalized keratinocyte cell lines. Therefore, we do not recommend the use of the immortalized keratinocyte cell lines HaCaT, HaSKpw, and SVTERT for analyzing inflammasome activation in keratinocytes; we strongly recommend the use of primary keratinocytes for these studies.

Abstract B022: Tumoral GLI1 controls the resident innate and adaptive tumor immune microenvironment in triple negative breast cancer

Abstract Background: Triple-negative breast cancer (TNBC) accounts for 15-20% of breast cancer (BC) cases but due to its aggressive nature and the lack of targeted treatment options, represents a disproportionately higher number of BC-related deaths. Compared to other BC subtypes, TNBCs are more inflamed with M2-like tumor-associated macrophages (TAMs) and cytotoxic T-lymphocytes (CTLs) which are associated with poor and good prognosis, respectively. Clinical trials have proven that immunogenic cancers can be effectively treated through immune checkpoint blockade (ICB), a treatment strategy that prevents cancer cells from silencing CTL-mediated attack. However, CTLs can be suppressed by M2-like TAMs which can limit ICB efficacy and support tumor growth. The hedgehog (HH) signaling pathway is highly activated in TNBC and higher expression of GLI1 is associated with worse overall survival. Recent pan-cancer analyses highlight a significant correlation between activated HH signaling and characteristics of immune evasion. We aim to clarify how activated HH signaling regulates resident innate and adaptive immune cells in the tumor microenvironment (TME) in TNBC. Methods: Primary K14-cre; Brca1 fl/fl ; P53 fl/fl (KBP) murine TNBC cells were transfected with CRISPR/Cas9 + sgRNA targeting GLI1. After isolating single cell clones and confirming GLI1 knockout (KO), KBP and KBP-GLI1-KO cells were orthotopically injected into the mammary fat pad of syngeneic immune-competent female mice and allowed to grow for 6-8 weeks. Tumor volume was measured once tumors were palpable, and tumors were harvested once the largest tumor reached ethical endpoint. Tumors were weighed at harvest and fluorescence activated cell sorting (FACS) was performed to determine if there was an effect on the composition of immune populations. Results: At harvest, KBP-GLI1-KO tumors were delayed in growth and significantly smaller than KBP tumors. FACS analysis showed that GLI1-KO tumors had increased CD4+ and CD8+ T cells and a reduced amount of Foxp3+ CD4+ Tregs. Furthermore, GLI1-KO tumors had significantly fewer F4/80+ CD11b+ TAMs within the TME. Amongst TAM populations, there was reduced CD206+ M2-like TAMs and an increase in CD80+ M1-like TAMs upon loss of GLI1. Similar trends were observed when KBP allografts were treated with the GLI1 inhibitor, GANT61. Immunohistochemical and RNAseq analysis are ongoing. Similar experiments with other KBP-GLI1-KO clones are currently being done. Conclusion: Here, we show that tumoral GLI1 not only promotes tumor growth, but also supports an immunosuppressive TME in TNBC. Abolishing GLI1 converted tumors to a pro-inflammatory phenotype marked by an increase in CD4+ and CD8+ T cells and a reduction in CD206+ M2-like TAMs. Future experiments are aimed at revealing the mechanisms by which GLI1 regulates immune cell recruitment to the TME and testing the effect of combination immunotherapy. Overall, these preliminary findings identify GLI1 as a potential therapeutic target to limit tumor growth and promote anti-tumor immunity. Citation Format: Aidan J Gray, Wanda Marini, Kiichi Murakami, Michael Reedijk. Tumoral GLI1 controls the resident innate and adaptive tumor immune microenvironment in triple negative breast cancer [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B022.

Excessive Erythrophagocytosis Accounts for Systemic Inflammation in Chronic Kidney Disease.

Chronic kidney disease (CKD) is associated with persistent systemic inflammation. Reduced red blood cell (RBC) survival in patients with CKD has been identified for several decades. The purpose of this study is to explore whether excessive erythrophagocytosis exists and contributes to systemic inflammation in CKD. A CKD rat model was induced by 5/6 nephrectomy. Erythrocyte osmotic fragility was determined with hypotonic NaCl solutions. Erythrocyte deformability was evaluated by filterability. RBC cell death was quantified using fluorescence-activated cell sorting analyses of fluorescent annexin V-bound surface phosphatidylserine (PS). Erythrophagocytosis was evaluated in vivo and in vitro. RT-qPCR and immunohistochemistry were used to determine the inflammatory effects after erythrophagocytosis. Erythrocyte osmotic fragility and deformability progressively declined, and the percentage of PS-exposing RBCs progressively increased in CKD rats. Levels of erythrophagocytosis in vivo were evaluated by autologous injection of CFSE-labeled erythrocytes. In comparison with the control group, higher fluorescence intensity of CFSE was detected in the spleen homogenates of rats with CKD. In vitro, more of erythrocytes from 5/6Nx rats were phagocytosed by peritoneal macrophages in comparison to those from control rats. Compared with macrophages phagocytosed control erythrocytes, macrophages phagocytosed CKD erythrocytes exhibited higher mRNA levels of IL-6, CXCL-10, CXCL-11, iNOS, IL-1β, ICAM-1 and MCP-1. Compared with the control group, the red pulp of rats with CKD exhibited higher levels of p-NFκB, IL-6, iNOS and CXCL-10. ELISA results showed significantly increased plasma levels of both IL-6 and CXCL-10 in patients with long-term hemodialysis compared with those in healthy controls (2.30 ± 1.38 pg/mL vs 1.33 ± 0.65 pg/mL, P=0.01; 78.11 ± 27.34 pg/mL vs 37.45 ± 7.08 pg/mL, P=0.001). Our results indicated that excessive erythrophagocytosis may contribute to systemic inflammation in CKD.

Immunomodulatory Effect of Adipose Stem Cell-Derived Extra-Cellular Vesicles on Cytokine Expression and Regulatory T Cells in Patients with Asthma.

Although mesenchymal stem cell (MSC)-derived extracellular vesicles (EVs) are as effective as MSCs in the suppression of allergic airway inflammation, few studies have evaluated the immunomodulatory capacity of MSC-derived EVs in patients with asthma. Thus, we assessed the effects of adipose stem cell (ASC)-derived EVs on cytokine expression and regulatory T cells (Tregs) in peripheral blood mononuclear cells (PBMCs) of asthmatic patients. PBMCs (1 × 106 cells/mL) were isolated from asthmatic patient and healthy controls and co-cultured with 1 μg/mL of ASC-derived EVs. Th (T helper) 1-, Th2-, and Treg-related cytokine expression, fluorescence-activated cell sorting analysis of CD4+CD25+FOXP3+ T cells, and co-stimulatory molecules were analyzed before and after ASC-derived EV treatment. The expression levels of IL-4 and costimulatory molecules such as CD83 and CD86 were significantly higher in PBMCs of asthmatic patients than in control PBMCs. However, ASC-derived EV treatment significantly decreased the levels of interleukin (IL)-4 and co-stimulatory molecules such as CD83 and CD86 in the phytohemagglutinin (PHA)-stimulated PBMC of asthmatic patients. Furthermore, ASC-derived EVs remarkably increased the transforming growth factor-β (TGF-β) levels and expression of Tregs in the PBMC of asthmatic patients. ASC-derived EVs induce Treg expansion and have immunomodulatory effects by downregulating IL-4 and upregulating TGF-β in PBMCs of asthmatic patients.

Dipeptidyl peptidase-4 marks distinct subtypes of human adipose stromal/stem cells with different hepatocyte differentiation and immunoregulatory properties

BackgroundHuman adipose-derived stromal/stem cells (hASCs) play important roles in regenerative medicine and numerous inflammatory diseases. However, their cellular heterogeneity limits the effectiveness of treatment. Understanding the distinct subtypes of hASCs and their phenotypic implications will enable the selection of appropriate subpopulations for targeted approaches in regenerative medicine or inflammatory diseases.MethodshASC subtypes expressing dipeptidyl peptidase-4 (DPP4) were identified via fluorescence-activated cell sorting (FACS) analysis. DPP4 expression was knocked down in DPP4+ hASCs via DPP4 siRNA. The capacity for proliferation, hepatocyte differentiation, inflammatory factor secretion and T-cell functionality regulation of hASCs from DPP4−, DPP4+, and control siRNA-treated DPP4+ hASCs and DPP4 siRNA-treated DPP4+ hASCs were assessed.ResultsDPP4+ hASCs and control siRNA-treated DPP4+ hASCs presented a lower proliferative capacity but greater hepatocyte differentiation capacity than DPP4− hASCs and DPP4 siRNA-treated DPP4+ hASCs. Both DPP4+ hASCs and DPP4− hASCs secreted high levels of vascular endothelial growth factor-A (VEGF-A), monocyte chemoattractant protein-1 (MCP-1), and interleukin 6 (IL-6), whereas the levels of other factors, including matrix metalloproteinase (MMP)-1, eotaxin-3, fractalkine (FKN, CX3CL1), growth-related oncogene-alpha (GRO-alpha, CXCL1), monokine induced by interferon-gamma (MIG), macrophage inflammatory protein (MIP)-1beta, and macrophage colony-stimulating factor (M-CSF), were significantly greater in the supernatants of DPP4+ hASCs than in those of DPP4− hASCs. Exposure to hASC subtypes and their conditioned media triggered changes in the secreted cytokine profiles of T cells from healthy donors. The percentage of functional T cells that secreted factors such as MIP-1beta and IL-8 increased when these cells were cocultured with DPP4+ hASCs. The percentage of polyfunctional CD8+ T cells that secreted multiple factors, such as IL-17A, tumour necrosis factor alpha (TNF-α) and TNF-β, decreased when these cells were cocultured with supernatants derived from DPP4+ hASCs.ConclusionsDPP4 may regulate proliferation, hepatocyte differentiation, inflammatory cytokine secretion and T-cell functionality of hASCs. These data provide a key foundation for understanding the important role of hASC subpopulations in the regulation of T cells, which may be helpful for future immune activation studies and allow them to be customized for clinical application.

67 Preclinical evaluation of PSMA-based68Ga-/225Ac-labeled radiotheranostic pair in a syngeneic mouse model of renal cell carcinoma

Abstract Background Despite the significant progress achieved with PD-1/PD-L1 inhibitors in the treatment of metastatic renal cell carcinoma (mRCC), most patients ultimately progress. Targeted radiotheranostics offer a new potential approach. Although a radiotheranostic platform targeting the prostate-specific membrane antigen (PSMA) has been tested in mRCC in patients preliminarily, thorough preclinical optimization has not been reported. Prostate-specific membrane antigen (PSMA) is overexpressed in tumor-associated neovascular endothelial cells of many solid tumors, including metastatic RCC. Furthermore, radiopharmaceutical therapy using β- and α-particle emitting agents causes immunomodulation by inducing immunogenic cell death, and release of tumor-associated antigens, potentially enhancing inflammatory phenotype. Here, we investigated whether PSMA-based radiotheranostics can be utilized to improve the efficacy of PD-1 therapy. Methods The PSMA+ RENCA model was developed by lentiviral transduction of RENCA (wt) cells and then characterized for basal and IFN-g induced PD-L1 expression. 68Ga-L1 and 225Ac-L1 were synthesized in high radiochemical yield and purity following our reported methods. Male and female BALB/c mice were used for tumor inoculation. 68Ga-L1 was evaluated in small animal PET/CT imaging in flank and PET/MR imaging in orthotopic implantation. A treatment study was conducted to assess the effect of combination therapy in seven groups in the flank tumors at 2 weeks post-inoculation: Control (saline); PD-1 (10 mg/kg); Anti-PD-1 (10 mg/kg)+axitinib (tyrosine kinase inhibitor, 5 mg/kg, oral gavage, for five days/wk); 225Ac-L1 (37 kBq); 225Ac-L1 (2×37 kBq, 1 wk apart); [225Ac-L1 (37 kBq)+PD-1 (10 mg/kg) and [225Ac-L1 2×37 kBq)+PD-1 (10 mg/kg)]. Therapeutic efficacy was assessed by tumor weight and time to progression of tumor volume doubling (TVD). To determine the mechanism of action of the 225Ac-L1/anti-PD-1 combination treatment, tumor-infiltrating lymphoid populations from tumor samples were collected at day 30, and Fluorescence-Activated Cell Sorting analysis was done with fluorochrome-labeled antibodies against CD45, CD3, CD8, IL10, and IL12. Results 68Ga-L1 and 225Ac-L1 confirmed 10-fold and 2-fold higher uptake, respectively, in the PSMA+ RENCA cells compared to RENCA (wt) cells. PET imaging in the flank model displayed ~7-fold higher accumulation of 68Ga-L1 in PSMA+ RENCA than the RENCA (wt). Two-fold higher accumulation of 68Ga-L1 was observed in orthotopic tumors than the normal kidneys during 1-3 h post-injection. Significant lung metastases were detected with 68Ga-L1 PET at 3 weeks in mice with orthotopic tumors. A combination therapy study was conducted using anti-PD-1 and anti-PD-1+axitinib and compared the efficacy with 225Ac-L1 as a single agent (37 kBq and 2×37 kBq, 1 wk apart) and in combination with PD-1. Median TVD increased from 12 d (control) to 16 d (anti-PD-1), 16 d (anti-PD-1+axitinib), 24 d [225Ac-L1 (37 kBq) P<0.001], 24 d [225Ac-L1 (2 × 37 kBq) P<0.0001}, 30 d [anti-PD-1+225Ac-L1 (1×37 kBq) P<0.0001], and undefined, [anti-PD-1+225Ac-L1 2×37 kBq), P<0.0001], respectively. Furthermore, treatment with 225Ac-L1 (2×37 kBq, 1 wk) resulted in a significant lowering of tumor growth (P< 0.01) compared to control, whereas anti-PD-1 (vs. control) alone moderately reduced tumor growth. The combination of the treatment of [PD-1+225Ac-L1 (2×37 kBq), P=0.0001] was the most effective in enhancing tumor growth inhibition compared with the PD-1+axitinib group. Flow cytometry of tumor-infiltrating immune cells of the treatment groups PD-1+225Ac-L1(37 kBq) and PD-1+225Ac-L1 (2×37 kBq) revealed a higher proportion of effector CD3+CD8+ T cells, accompanied by a significant decline in the proportion of immunosuppressive and pro-tumoral CD8+IL10+ T cells and increase in antitumor CD8+IL12+ T cells compared to untreated and treatment control groups (PD-1 or PD-1+axitinib groups). Conclusions Combining radiotheranostic platform, 68Ga-L1/225Ac-L1 with PD-1 therapy reduces tumor burden and improves TVD in a syngeic model of RCC. This is a promising option for metastatic RCC patients with low and heterogeneous PSMA expression. Translation of this method will be pursued actively. DOD CDMRP Funding: yes

Comparison of NK cell count between 1% and 10% FBS culture media concentration by FACS analysis

Recently, there has been a growing research interest in the application of immunotherapy for cancer treatment. Various approaches have been developed, and one of these methods involves utilizing Natural Killer (NK) cells of the immune system to specifically target cancer cells. Research on this method necessitates the mass and stable production of NK cells through culturing. For NK cell culture, Fetal Bovine Serum (FBS) is widely used in the industry at concentrations ranging from 10% to 20%. In an effort to explore a more efficient culturing technique, this study aims to investigate the effect of 1% FBS on cell viability of NK cells in cell culture. Because NK cells are usually defined by cell surface molecules, the efficacy of using a lower FBS concentration was quantitatively measured using Fluorescence-Activated Cell Sorting (FACS). The cell counts of cells cultured in 1% FBS was compared to those of cells cultured in 10% FBS. The results showed that no significant difference was found between cell count of cells cultured in 1% and 10% FBS. Thus, 1% FBS concentration culturing method was not found to be inferior. Further research is needed on the effect of replicating cancer microenvironment on NK cell viability.

Negative regulation of HDAC3 transcription by histone acetyltransferase TIP60 in colon cancer

BackgroundColon cancer is the third most common cancer globally. The expression of histone deacetylase 3 (HDAC3) is upregulated, whereas the expression of tat interactive protein, 60 kDa (TIP60) is downregulated in colon cancer. However, the relationship between HDAC3 and TIP60 in colon cancer has not been clearly elucidated.ObjectiveWe investigated whether TIP60 could regulate the expression of HDAC3 and suppress colon cancer cell proliferation.MethodsRNA sequencing data (GSE108834) showed that HDAC3 expression was regulated by TIP60. Subsequently, we generated TIP60-knockdown HCT116 cells and examined the expression of HDAC3 by western blotting and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). We examined the expression pattern of HDAC3 in various cancers using publicly available datasets. The promoter activity of HDAC3 was validated using a dual-luciferase assay, and transcription factors binding to HDAC3 were identified using GeneCards and Promo databases, followed by validation using chromatin immunoprecipitation-quantitative polymerase chain reaction. Cell proliferation and apoptosis were assessed using colony formation assays and fluorescence-activated cell sorting analysis of HCT116 cell lines.ResultsIn response to TIP60 knockdown, the expression level and promoter activity of HDAC3 increased. Conversely, when HDAC3 was downregulated by overexpression of TIP60, proliferation of HCT116 cells was inhibited and apoptosis was promoted.ConclusionTIP60 plays a crucial role in the regulation of HDAC3 transcription, thereby influencing cell proliferation and apoptosis in colon cancer. Consequently, TIP60 may function as a tumor suppressor by inhibiting HDAC3 expression in colon cancer cells.

Programmed cell death-1 is involved with peripheral blood immune cell profiles in patients with hepatitis C virus antiviral therapy.

Mutations in the non-structural protein regions of hepatitis C virus (HCV) are a cause of a non-sustained virological response (SVR) to treatment with direct-acting antivirals (DAAs) for chronic hepatitis; however, there are non-SVR cases without these mutations. In this study, we examined immune cell profiles in peripheral blood before and after ombitasvir/paritaprevir/ritonavir treatment and screened for genes that could be used to predict the therapeutic effects of DAAs. Fluorescence-activated cell sorting analysis indicated that the median frequencies of programmed cell death-1-positive (PD-1+) effector regulatory T cells (eTregs), PD-1+CD8+ T cells, and PD-1+Helper T cells were decreased significantly in SVR cases, but without significant changes in non-SVR cases. The frequency of PD-1+ naïve Tregs was significantly higher in the SVR group than in the non-SVR group before and after treatment. Similar results were found in patients treated with other DAAs (e.g., daclatasvir plus asunaprevir) and supported an immune response after HCV therapy. RNA-sequencing analysis indicated a significant increase in the expression of genes associated with the immune response in the SVR group, while genes related to intracellular and extracellular signal transduction were highly expressed in the non-SVR group. Therefore, we searched for genes associated with PD-1+ eTregs and CD8+ T cells that were significantly different between the SVR and non-SVR groups and found that T-box transcription factor 21 was associated with the non-SVR state. These results indicate that PD-1-related signaling pathways are associated with a non-SVR mechanism after DAAs treatment separate from mutation-related drug resistance.

Neuroprotective Effect of Fructus Ligustri Lucidi in Spinal Cord Neuron Injury during H2O2-Mediated Oxidative Stress

Oxidative stress-induced neuronal damage is a significant factor contributing to spinal cord injury. Although previous research has shown that Fructus Ligustri Lucidi (FLL) has neuroprotective benefits in SH-SY5Y, BV2, and PC12 cells, its impact on primary spinal cord neurons, which more accurately reflect the characteristics of central nervous system neurons, remains unexplored. This research investigated how FLL can protect rat primary spinal cord neurons from injury triggered by hydrogen peroxide (H2O2)-mediated oxidative stress. Cell viability, generation of reactive oxygen species (ROS), upregulation of inducible nitric oxide synthase (iNOS), activation of the Nrf2/HO-1 antioxidant pathway, and mitochondrial superoxide were assessed. Rat primary spinal cord neurons were not adversely affected by concentrations of FLL extract up to 100 μg/mL. Furthermore, FLL extract showed a significant protective effect against H2O2-induced neuronal toxicity at 10–100 μg/mL. Fluorescence-activated cell sorting analysis revealed that FLL extract inhibited H2O2-induced ROS generation in a dose-dependent manner. Immunocytochemistry and gene expression analysis confirmed that FLL extract reduced the overexpression of iNOS induced by H2O2 and enhanced the stimulation of the Nrf2/HO-1 pathway, crucial for antioxidant responses. In conclusion, FLL extract demonstrated neuroprotective effects on rat primary spinal cord neurons against the oxidative stress induced by H2O2. FLL extract effectively preserved cell viability, reduced ROS generation, suppressed iNOS overexpression, and activated the Nrf2/HO-1 antioxidant pathway. These results highlight the capacity of FLL extract as a neuroprotective agent against oxidative stress-related spinal neuron damage.

UV-Inactivated rVSV-M2e-Based Influenza Vaccine Protected against the H1N1 Influenza Challenge.

To investigate the immune responses and protection ability of ultraviolet light (UV)-inactivated recombinant vesicular stomatitis (rVSV)-based vectors that expressed a fusion protein consisting of four copies of the influenza matrix 2 protein ectodomain (tM2e) and the Dendritic Cell (DC)-targeting domain of the Ebola Glycoprotein (EΔM), (rVSV-EΔM-tM2e). In our previous study, we demonstrated the effectiveness of rVSV-EΔM-tM2e to induce robust immune responses against influenza M2e and protect against lethal challenges from H1N1 and H3N2 strains. Here, we used UV to inactivate rVSV-EΔM-tM2e and tested its immunogenicity and protection in BALB/c mice from a mouse-adapted H1N1 influenza challenge. Using Enzyme-Linked Immunosorbent Assay (ELISA) and Antibody-Dependent Cellular Cytotoxicity (ADCC), the influenza anti-M2e immune responses specific to human, avian and swine influenza strains induced were characterized. Likewise, the specificity of the anti-M2e immune responses induced in recognizing M2e antigen on the surface of the cell was investigated using Fluorescence-Activated Cell Sorting (FACS) analysis. Like the live attenuated rVSV-EΔM-tM2e, the UV-inactivated rVSV-EΔM-tM2e was highly immunogenic against different influenza M2e from strains of different hosts, including human, swine, and avian, and protected against influenza H1N1 challenge in mice. The FACS analysis demonstrated that the induced immune responses can recognize influenza M2 antigens from human, swine and avian influenza strains. Moreover, the rVSV-EΔM-tM2e also induced ADCC activity against influenza M2e from different host strains. These findings suggest that UV-inactivated rVSV-EΔM-tM2e could be used as an inactivated vaccine against influenza viruses.

F127/chlorin e6-nanomicelles to enhance Ce6 solubility and PDT-efficacy mitigating lung metastasis in melanoma.

Photodynamic Therapy (PDT) is a promising paradigm for treating cancer, especially superficial cancers, including skin and oral cancers. However, the effectiveness of PDT is hindered by the hydrophobicity of photosensitizers. Here, chlorin e6 (Ce6), a hydrophobic photosensitizer, was loaded into pluronic F127 micelles to enhance solubility and improve tumor-specific targeting efficiency. The resulting Ce6@F127 Ms demonstrated a significant increase in solubility and singlet oxygen generation (SOG) efficiency in aqueous media compared to free Ce6. The confocal imaging and fluorescence-activated cell sorting (FACS) analysis confirmed the enhanced internalization rate of Ce6@F127 Ms in murine melanoma cell lines (B16F10) and human oral carcinoma cell lines (FaDu). Upon laser irradiation (666nm), the cellular phototoxicity of Ce6@F127 Ms against B16F10 and FaDu was approximately three times higher than the free Ce6 treatment. The in vivo therapeutic investigations conducted on a murine model of skin cancer demonstrated the ability of Ce6@F127 Ms, when combined with laser treatment, to penetrate solid tumors effectively, which resulted in a significant reduction in tumor volume compared to free Ce6. Further, the Ce6@F127 Ms demonstrated upregulation of TUNEL-positive cells, downregulation of proliferation markers in tumor tissues, and prevention of lung metastasis with insignificant levels of proliferating cells and collagenase, as validated through immunohistochemistry. Subsequent analysis of serum and blood components affirmed the safety and efficacy of Ce6@F127 Ms in mice. Consequently, the developed Ce6@F127 Ms exhibits significant potential for concurrently treating solid tumors and preventing metastasis. The photodynamic formulation holds great clinical translation potential for treating superficial tumors.

Abstract PO1-25-06: Integrated analysis of single-cell RNA and VDJ-sequencing data to identify T cell marker expressed on antigen-specific T cells

Abstract Background In recent years, the advancement of adoptive cell transfer-based immunotherapies has significantly contributed to the evolution of cancer treatment. The crucial step in achieving successful treatment lies in the identification of T cells that exhibit reactivity towards tumor-specific antigens. However, the heterogeneous composition of tumor antigen-specific T cells poses a challenge as there are no standardized biomarkers available for their identification. To overcome this limitation, we investigated alternative approaches, employing single cell RNA and VDJ sequencing to identify antigen-specific T cells. Methods First, peripheral blood mononuclear cells (PBMCs) obtained from healthy human donors were stained with carboxyfluorescein succinimidyl ester (CFSE) to facilitate the identification of proliferating antigen-specific T cells. Then the PBMCs were exposed to 1 ug/ml of CMV pp65 peptide. After a 2-day incubation period with the CMV peptide, interleukin-2 (IL-2) was administered to stimulate T cell expansion. At various time points (0, 1, 2, 3, 5, and 7 days) following the CMV peptide treatment, CD8+ T cells were isolated through fluorescence-activated cell sorting (FACS) analysis. On day 7, the CD8+ T cells were further segregated into CFSE- and CFSE+ cell populations. The single-cell transcriptomes and T cell receptor (TCR) repertoire of the CD8+ T cells were subsequently examined using the Chromium Single Cell Reagent Kit. Results The TCR repertoire analysis of CD8+ CFSE- T cells revealed the dominance of 10 major clones, accounting for 93.9% of the total cells. These clones were confirmed to be CMV-specific through various in vitro assays, including NFAT-luciferase, IFN-γ ELISA, and cytotoxicity assay. In contrast, CD8+ CFSE+ T cells did not exhibit significant overlap with the major TCR clones found in CFSE- CD8+ T cells, comprising only 0.02% of the total cells. Gene set enrichment analysis demonstrated that the upregulated genes in CFSE- CD8+ T cells, when compared to CFSE+ T cells, were related to cell cycle proliferation and T cell cytotoxicity. Furthermore, these genes exhibited a matching upregulation pattern with CFSE- T cells from another batch of the same donor, as well as from two other healthy donors. In addition, there was a moderate increase in the expression of the upregulated genes in CFSE- CD8+ T cells at day 3 compared to day 0-2. In this end, we selected a set of nine genes that were consistently upregulated in CFSE- CD8+ T to serve as markers for antigen-specific T cells, employing a logistic regression model. This gene set showed high sensitivity (97.7%) and specificity (95.6%) in identifying T cell clones that respond to CMV antigen at day 3. Conclusions We have discovered potential markers for antigen-specific CD8+ T cells. These results can offer the promising opportunity for earlier isolation of T cells that exhibit reactivity towards tumor-specific antigens. This breakthrough has significant implications, as it can potentially contribute to cost savings in adoptive cell transfer-based immunotherapies. Citation Format: Byung-Kwan Jeong, Young-Ae Kim, Jungwook Park, Baknoon Ham, Jiheyong Kim, Chae Lyul Lim, Hee Jin Lee. Integrated analysis of single-cell RNA and VDJ-sequencing data to identify T cell marker expressed on antigen-specific T cells [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO1-25-06.

Development and validation of a flow cytometry method to examine circulating leukocyte subpopulations in barramundi (Lates calcarifer)

Bacterial infections are a major contributor to losses in aquaculture production. Diagnosis of these bacterial diseases is based on sacrificing fish and isolating the infectious agent from the internal organs. Infections lead to an inflammatory response in the host that is characterized by changes in leukocyte profile and activity. We hypothesized that the profile of circulating peripheral blood leukocytes and markers of their activity, such as reactive oxygen species production, would change following an event of bacterial infection in fish. We therefore developed a flow cytometry-based methodology for analyzing blood leukocytes in barramundi (Lates calcarifer), then used it to compare healthy fish to those infected with a common pathogenic bacterium, Vibrio harveyi. The initial step of the analysis relied on the effective separation of erythrocytes and leukocytes, and two methods were tested: one based on hypotonic lysis of red blood cells, and the other involving stain-based differentiation using carboxyfluorescein succinimidyl ester (CFSE). Fluorescence-activated cell sorting analysis revealed significant differences in leukocyte parameters of infected and control fish using the stain-based approach vs. hypotonic lysis. Changes in blood leukocytes included an increase in the proportion of monocytes and decrease in that of lymphocytes in infected fish. Furthermore, cell size and granularity of the different leukocyte populations changed over time in infected fish as compared to controls. Monitoring peripheral blood leukocytes provides a non-lethal analysis of inflammation that allows repeated sampling of individual fish over time. This is beneficial given the high variability between individual fish. The use of CFSE-staining for leukocyte isolation proved to be advantageous over a method based on lysis of erythrocytes.

DA-6034 ameliorates hepatic steatosis and inflammation in high fat diet-induced obese mice.

Nonalcoholic fatty liver disease (NAFLD) is characterized by an increase in hepatic triglyceride content and increased inflammatory macrophage infiltration through the C-C motif chemokine receptor (CCR) 5 pathway in the liver. DA-6034 (7-carboxymethyloxy-3',4',5-trimethoxy flavone), is a synthetic derivative of eupatilin that exhibits anti-inflammatory activity in inflammatory bowel disease. However, the effect of DA-6034 on the inflammatory response in NAFLD is not well elucidated. Therefore, we aimed to determine the effect of DA-6034 on hepatic steatosis and inflammation. Forty male C57BL/6J mice were divided into the following four groups: (1) regular diet (RD), (2) RD with DA-6034, (3) high fat diet (HFD), and (4) HFD with DA-6034. All mice were sacrificed 12 weeks after the start of the experiment. The effects of DA-6034 on macrophages were assessed using RAW264.7 cells. DA-6034 not only reduced hepatic triglyceride levels and lipid accumulation but also macrophage infiltration and proinflammatory cytokines in HFD-fed mice. According to fluorescence-activated cell sorter analysis, DA-6034 reduced the CD8+ T cell fraction in the liver of HFD-fed mice. DA-6034 also reduced CCR5 expression and the migration of liver macrophages in HFD-fed mice and inhibited CCR2 ligand and CCR4 ligand, which stimulated the migration of macrophages. Overall, DA-6034 attenuates hepatic steatosis and inflammation in obesity by regulating CCR5 expression in macrophages.

Inhibition of leukocyte migration after ischemic stroke by VE-cadherin mutation in a mouse model leads to reduced infarct volumes and improved motor skills.

To distinguish between the genuine cellular impact of the ischemic cascade by leukocytes and unspecific effects of edema and humoral components, two knock-in mouse lines were utilized. Mouse lines Y731F and Y685F possess point mutations in VE-cadherin, which lead to a selective inhibition of transendothelial leukocyte migration or impaired vascular permeability. Ischemic stroke was induced by a model of middle cerebral artery occlusion. Analysis contained structural outcomes (infarct volume and extent of brain edema), functional outcomes (survival analysis, rotarod test, and neuroscore), and the extent and spatial distribution of leukocyte migration (heatmaps and fluorescence-activated cell sorting (FACS) analysis). Inhibition of transendothelial leukocyte migration as in Y731F mice leads to smaller infarct volumes (52.33±4719 vs. 70.43±6483mm3 , p=.0252) and improved motor skills (rotarod test: 85.52±13.24s vs. 43.06±15.32s, p=.0285). An impaired vascular permeability as in Y685F mice showed no effect on structural or functional outcomes. Both VE-cadherin mutations did not influence the total immune cell count or spatial distribution in ischemic brain parenchyma. Selective inhibition of transendothelial leukocyte migration by VE-cadherin mutation after ischemic stroke in a mouse model leads to smaller infarct volumes and improved motor skills.

Periostin Modulating Mycoplasma pneumoniae Pneumonia in Children Related to Th17 Cell Function

Abstract Objective Mycoplasma pneumoniae pneumonia (MPP) is recognized as a significant respiratory tract infection in children. Periostin associates with airway remodeling, and the T helper 17 (Th17) cells play a crucial role against M. pneumoniae infection. This study investigates the effect of periostin in Th17 cells and the associated mechanism in MPP. Methods The study investigated the role of periostin stimulated with pulmonary bronchoalveolar lavage fluid (BALF) from MPP. Levels of infection of M. pneumoniae were determined using quantitative real-time polymerase chain reaction. The periostin was cloned into vector, and siRNA fragment were synthesized. The Th17 cells were transfected with the vector and the fragment, and its expression and proinflammatory cytokines (interleukin [IL]-6, tumor necrosis factor [TNF]-α, and IL-1β) were determined using western blot. The cell apoptosis, migration, and proliferation were measured using flow cytometer, transwell migration, and cell counting kit-8 assay, respectively. Results The results showed that periostin expression had a positive correlation with MPP severity. Fluorescence-activated cell sorting analysis showed that the periostin inhibited the apoptosis of Th17 cells. Moreover, transwell migration showed a significant increased migration in Th17 cell was detected treated with BALF, and selective knockdown of periostin by specific siRNA had negative effect on cell migration. Western blot analysis showed the periostin induced the expression of the proinflammatory cytokines (IL-6, TNF-α, and IL-1β), and downregulation of periostin could decrease the expression of cytokines in MPP group. Conclusion The study suggested that periostin is required for Th17 cells migration, and it also has effect on Th17 apoptosis and proinflammatory cytokines expression in MPP.

Intranasal administration enhances size-dependent pulmonary phagocytic uptake of poly(lactic-co-glycolic acid) nanoparticles

BackgroundNanoparticles exhibit distinct behaviours within the body, depending on their physicochemical properties and administration routes. However, in vivo behaviour of poly(lactic-co-glycolic acid) (PLGA) nanoparticles, especially when administered nasally, remains unexplored; furthermore, there is a lack of comparative analysis of uptake efficiency among different administration routes. Therefore, here, we aimed to comprehensively investigate the real-time in vivo behaviour of PLGA nanoparticles across various administration routes. PLGA-NH2 nanoparticles of three sizes were synthesised using an oil-in-water single-emulsion method. We assessed their uptake by murine macrophage RAW264.7 cells using fluorescence microscopy. To enable real-time tracking, we conjugated p-SCN-Bn-deferoxamine to PLGA-NH2 nanoparticles and further radiolabelled them with 89Zr-oxalate before administration to mice via different routes. Nanoparticle internalisation by lung immune cells was monitored using fluorescence-activated cell sorting analysis.ResultsThe nanoparticle sizes were 294 ± 2.1 (small), 522.5 ± 5.58 (intermediate), and 850 ± 18.52 nm (large). Fluorescent labelling did not significantly alter the nanoparticle size and charge. The level of uptake of small and large nanoparticles by RAW264.7 cells was similar, with phagocytosis inhibition primarily reducing the internalisation of large particles. Positron emission tomography revealed that intranasal delivery resulted in the highest and most targeted pulmonary uptake, whereas intravenous administration led to accumulation mainly in the liver and spleen. Nasal delivery of large nanoparticles resulted in enhanced uptake by myeloid immune cells relative to lymphoid cells, whereas dendritic cell uptake initially peaked but declined over time.ConclusionsOur study provides valuable insights into advancing nanomedicine and drug delivery, with the potential for expanding the clinical applications of nanoparticles.