Transwell Co-culture Research Articles

Streptococcus mutans regulates ubiquitin modification of Candida albicans in the bacterial-fungal interaction.

The ecological interplay between Streptococcus mutans and Candida albicans within dental plaque biofilms is an important factor driving pathogenesis of dental caries. This study aimed to investigate S. mutans regulation of C. albicans growth and virulence through extracellular membrane vesicles (EMVs) and modulation of ubiquitination, a key protein post-translational modification. We established a transwell co-culture model to enable "contact-independent" interactions between S. mutans and C. albicans. S. mutans EMVs were found to directly associate with C. albicans cells and promote biofilm formation and growth. Quantitative ubiquitination profiling revealed S. mutans dramatically alters the ubiquitination landscape in C. albicans. We identified 10,661 ubiquitination sites across the C. albicans proteome and their enrichment in pathways related to translation, metabolism, and stress adaptation. Co-culture with S. mutans led to upregulation of ubiquitination on 398 proteins involved in sugar catabolism and generation of reducing power. S. mutans upregulated ubiquitination of superoxide dismutase-3 of C. albicans, inducing its degradation and heightened reactive oxygen species levels, and concomitantly stimulated C. albicans growth. Our findings elucidate EMVs and ubiquitination modulation as key mechanisms governing the S. mutans-C. albicans interplay and provide new insights into the promotion of a cariogenic oral biofilm environment. This study significantly advances understanding of the complex molecular interactions underlying dental plaque dysbiosis and caries pathogenesis.

Role of CXCL10 released from osteocytes in response to TNF-α stimulation on osteoclasts

Tumor necrosis factor-alpha (TNF-α) is a significant cytokine that regulates bone resorption under inflammatory conditions. However, its mechanism of action in osteocytes remains unclear. In this study, highly purified osteocytes were isolated from dentin matrix protein 1 (DMP1)-Topaz mice using cell sorter. RNA sequencing (RNA-seq) revealed that TNF-α stimulation increased C-X-C motif chemokine ligand 10 (CXCL10) gene expression in osteocytes. Although CXCL10 did not affect osteoclast differentiation in vitro, it enhanced the migration of osteoclast precursors. Additionally, in the transwell co-culture system, TNF-α induced the migration of osteoclast precursors. However, this effect was attenuated by a CXCL10-neutralizing antibody. In vivo, mice were administered supracalvarial injections of TNF-α with or without the CXCL10-neutralizing antibody for 5 days. The percentage of CXCL10-positive osteocytes increased after TNF-α administration. Additionally, osteoclast formation and bone resorption were assessed. CXCL10-neutralizing antibody-treated calvariae exhibited a significantly lower number of osteoclasts and bone resorption than those treated with TNF-α alone. These results indicated that TNF-α-induced CXCL10, which affects the migration of osteocyte-derived osteoclast precursors, may enhance TNF-α-triggered osteoclast formation and bone resorption in vivo.

P0014 Mesenteric inflammation-associated fibroblasts are critical in the pathogenesis of Crohn’s disease

Abstract Background The Mesentery, initially considered as a structure support of abdominal organs, has emerged as an active participant in the inflammatory processes of Crohn's disease (CD). It serves as a central hub for immune cell activity, including macrophages, T cells, and B cells, driving the propagation of inflammation. Additionally, mesenteric fibroblasts play a crucial role in CD-associated fibrosis. These fibroblasts are activated by pro-fibrotic cytokines such as TGF-β and IL-13, leading to excessive extracellular matrix (ECM) deposition, which contributes to intestinal wall thickening and the formation of strictures. In this study, we aim to explore the specific role of mesenteric fibroblasts in the pathogenesis of CD. Methods Magnetic-activated cell sorting was utilized to isolate mesenteric inflammation-associated fibroblasts (IAFs) and normal fibroblasts (NFs) from surgical samples of patients with Crohn's disease (CD) and noncancerous colonic polyps (control group). Various cell-based assays, including cell viability, invasion, and collagen contraction assays, were conducted to investigate phenotypic differences between NFs and IAFs. To assess the impact of NFs and IAFs on colonic epithelium, Co-culture experiments were performed with the isolated fibroblasts and Caco-2 and HT-29 colorectal cancer cell lines using transwell and 3D Matrigel culture systems. Results IAFs exhibited a significantly faster growth rate than NFs (Figure 1B; fold change [FC] 1.60 ± 0.04, P < 0.001). Furthermore, IAFs showed markedly higher wound healing (Figure 1C; FC 1.44 ± 0.15, P = 0.004), invasion (Figure 1D; FC 1.45 ± 4.7, P = 0.035), and collagen contraction activities (Figure 1E; FC 1.26 ± 4.73, P = 0.007) compared to NFs. In a 3D Matrigel co-culture system with Caco-2 spheres, abnormal lumen formation with invasive structures of Caco-2 spheres was significantly higher in IAFs compared to NFs (Figure 2A; FC 1.3 ± 0.08, P < 0.001). Similarly, a fluorescein transport assay using a transwell co-culture system revealed that IAFs caused significantly greater epithelial disruption compared to NFs (Figure 2B; FC 1.25 ± 0.04, P = 0.04). Conditioned media from IAFs upregulated the expression of mesenchymal markers, such as ZEB1 (FC 2.67 ± 0.2, P < 0.01) and CDH2 (FC 2.11 ± 0.54, P < 0.05), in Caco-2 cells when compared with NFs (Figure 2C). Conclusion These findings suggest that mesenteric IAFs play an active role in the inflammatory and fibrotic processes in the pathogenesis of CD. Targeting mesenteric IAFs and their associated pathways may provide a promising therapeutic approach for managing CD.

P0043 Fecal extracellular vesicles from healthy individuals: A novel therapeutic approach for patients with Inflammatory Bowel Disease

Abstract Background Inflammatory bowel disease (IBD) is a chronic, relapsing inflammatory disease that consists of two main types: Crohn's disease and ulcerative colitis. One of the main causes of this disease is the disruption of the diversity of the gut microbiome and dysregulation of the interactions between microbes and the human immune system. So far, no definitive cure has been identified for the disease, and current treatments are only for temporary suppression of severe inflammatory responses. One treatment option currently being investigated in clinical trials is fecal transplants from healthy donors to patients with IBD. Extracellular vesicles (EVs), released by various cell types and microbes residingt in the gastrointestinal tract, can play an important role in the disease progression and treatment of IBD. In this study, we investigate the therapeutic potential of extracellular vesicles extracted from the feces of healthy individuals in the in vitro model of inflammatory bowel disease. Methods An in vitro model of IBD was established using a transwell co-culture system of Caco-2 intestinal epithelial cells and RAW264.7 macrophages. Inflammation was induced in macrophages using lipopolysaccharide (LPS). Stool samples were obtained from healthy donors and IBD patients. Stools were suspended in Tris-EDTA-based buffer in a 1:5 ratio and centrifuged. The supernatant was filtered and centrifuged at 100,000 x g to isolate EVs. Dynamic light scattering (DLS) and Transmission electron microscopy (TEM) were performed to characterize EVs in size and shape. The effects of EVs isolated from healthy individuals and IBD patients on the intestinal cells and expression of epithelial barrier markers were investigated in the in vitro IBD model. Results DLS results revealed that the size of isolated EVs was mainly distributed around 100-200 nm. TEM results showed that the EVs were round- or oval-shaped and their structures did not alter by ultracentrifugation. Inflammation induction using LPS led to changes in the morphology of intestinal cells. However, the shape of cells after treatment with EVs derived from feces of healthy donors was similar to the control group. Intriguingly, the cell shapes shifted toward the inflammatory phase when they were treated with stool-derived EVs of IBD patients. Molecular findings showed that stool-derived EVs of healthy individuals could restore the expression of epithelial cell markers in the inflamed intestinal cells, preserving epithelial barrier function, similar to what was observed in the non-inflamed cells. Conclusion Stool-derived EVs of healthy individuals can be introduced as a new solution for the treatment of IBD patients, although further studies on animal models are needed to enter the clinic.

Single-cell transcriptomic analysis reveals characteristic feature of macrophage reprogramming in liver Mallory-Denk bodies pathogenesis

Chronic liver diseases are highly linked with mitochondrial dysfunction and macrophage infiltration. Mallory-Denk bodies (MDBs) are protein aggregates associated with hepatic inflammation, and MDBs pathogenesis could be induced in mice by feeding 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC). Here, we investigate the macrophage heterogeneity and the role of macrophage during MDBs pathogenesis on DDC-induced MDBs mouse model by single-nucleus RNA sequencing (snRNA-seq). We defined liver macrophages into four distinct subsets including monocyte-derived macrophages (MDMs) subset and three Kupffer cells (KCs) subsets (Gpnmbhigh KCs, Peam1high KCs, and Gpnmblow Pecam1low KCs). Particularly, we identified a novel Gpnmbhigh KCs subset as lipid-associated macrophage (LAM) with high expression of Trem2, CD63, and CD9. Interestingly, LAM showed a potential immunosuppressive characteristic by expressing anti-inflammatory genes IL-7R during the MDBs formation. Using contact and transwell co-culture systems, the released mtDNA from hepatocytes was found to induce the activation of inflammasome in macrophages. Furthermore, we revealed the damaged DNA could activate the NOD-like receptor family pyrin domain containing-3 (NLRP3) inflammasome and subsequently form apoptosis-associated speck-like protein containing a caspase recruit domain (ASC) specks of liver macrophages. Collectively, our results firstly revealed macrophage heterogeneity and inflammasome activation by mtDNA from injured liver during MDBs pathogenesis, providing crucial understanding of pathogenesis of chronic liver disease.

Enhanced osteo-angiogenic coupling by a bioactive cell-free fat extract (CEFFE) delivered through electrospun fibers.

Regeneration of functional bone tissue relies heavily on achieving adequate vascularization in engineered bone constructs following implantation. This process requires the close integration of osteogenesis and angiogenesis. Cell-free fat extract (CEFFE or FE), a recently emerging acellular fat extract containing abundant growth factors, holds significant potential for regulating osteo-angiogenic coupling and promoting regeneration of vascularized bone tissue. However, its specific role in modulating the coupling between angiogenesis and osteogenesis remains unclear. Our previous research demonstrated that FE-decorated electrospun fibers of polycaprolactone/gelatin (named FE-PDA@PCL/GT) exhibited pro-vasculogenic capabilities both in vitro and in vivo (D. Li, Q. Li, T. Xu, X. Guo, H. Tang, W. Wang, W. Zhang and Y. Zhang, Pro-vasculogenic fibers by PDA-mediated surface functionalization using cell-free fat extract (CEFFE), Biomacromolecules 2024, 25, 1550-1562). Herein, we firstly demonstrated that the FE-PDA@PCL/GT fibers also significantly stimulated osteogenesis in a mouse calvaria osteoblast-like cell line MC3T3-E1 cells, as evidenced by the increased production of alkaline phosphatase (ALP), mineral deposits, and collagen I, as well as the upregulated expression of osteogenic marker genes in the osteoblasts. Using a transwell co-culture system, we further demonstrated that the release of FE from the FE-PDA@PCL/GT fibers not only promoted osteogenesis and angiogenesis but also markedly enhanced the paracrine functions and reciprocal communications between endothelial cells and osteoblasts. This dynamic interaction played a key role in the observed enhancement of osteo-angiogenic coupling. With the confirmed pro-osteogenic and pro-angiogenic properties of FE-PDA@PCL/GT, it is envisaged that these newly engineered bioactive fibers can be used to develop highly biomimicking bone constructs. These constructs are designed to promote native-like cell-scaffold and cell-cell interactions, which are essential for the effective regeneration of defected bone tissue with adequate vasculature.

Neferine Targeted the NLRC5/NLRP3 Pathway to Inhibit M1-type Polarization and Pyroptosis of Macrophages to Improve Hyperuricemic Nephropathy.

Neferine (Nef) has a renal protective effect. This research intended to explore the impact of Nef on hyperuricemic nephropathy (HN). Adenine and potassium oxonate were administered to SD rats to induce the HN model. Bone marrow macrophages (BMDM) and NRK-52E were used to construct a transwell co-culture system. The polarization of BMDM and apoptosis levels were detected using immunofluorescence and flow cytometry. Renal pathological changes were detected using hematoxylin-eosin (HE) and Masson staining. Biochemical methods were adopted to detect serum in rats. CCK-8 and EDU staining were used to assess cell activity and proliferation. RT-qPCR and western blot were adopted to detect NLRC5, NLRP3, pyroptosis, proliferation, and apoptosis-related factor levels. After Nef treatment, renal injury and fibrosis in HN rats were inhibited, and UA concentration, urinary protein, BUN, and CRE levels were decreased. After Nef intervention, M1 markers, pyroptosis-related factors, and NLRC5 levels in BMDM stimulated with uric acid (UA) treatment were decreased. Meanwhile, the proliferation level of NRK-52E cells co-cultured with UA-treated BMDM was increased, but the apoptosis level was decreased. After NLRC5 overexpression, Nef-induced regulation was reversed, accompanied by increased NLRP3 levels. After NLRP3 was knocked down, the levels of M1-type markers and pyroptosis-related factors were reduced in BMDM. Nef improved HN by inhibiting macrophages polarized to M1-type and pyroptosis by targeting the NLRC5/NLRP3 pathway. This research provides a scientific theoretical basis for the treatment of HN.

CD69+CD103+CD8+ tissue-resident memory T cells possess stronger anti-tumor activity and predict better prognosis in colorectal cancer

BackgroundColorectal cancer (CRC) is one of the most prevalent cancers worldwide. Despite advancements in therapeutic methodologies, it still causes a high rate of patient mortality. CD8+ tissue-resident memory T (TRM) cells are strategically positioned to mediate effective anti-tumor responses. However, the characteristic surface molecules and functions of CD8+ TRM cells exhibit significant heterogeneity.MethodsThe roles and anti-tumor biological functions of different CD8+ TRM subsets in CRC were determined by clinical CRC samples, bioinformatics analysis, and in vitro experiments including co-culture experiments and transwell migration assays. The signaling pathways that synergistically regulate the differentiation of CD8+ TRM cells were identified by in vitro CD8+ T cell activation and inhibition assays, and the functioning transcription factors were predicted using the UCSC and JASPAR databases.ResultsWe found that different CD8+ TRM subsets existed in CRC tumor tissues, which were identified as CD69−CD103−CD8+ TRM, CD69+CD103−CD8+ TRM (SP CD8+ TRM), and CD69+CD103+CD8+ TRM (DP CD8+ TRM) subsets. Compared with SP CD8+ TRM cells, increased infiltration of DP CD8+ TRM cells predicted better prognosis and played a protective role mainly in tumor invasion and lymph node metastasis of CRC. DP CD8+ TRM cells expressed higher levels of effector molecules and exerted stronger anti-tumor effects in a FAS/FASL pathway-dependent manner. Additionally, DP CD8+ TRM cells secreted higher levels of CXCL13 and recruited B cells into tumor tissues through the CXCL13/CXCR5 signaling axis to form tertiary lymphoid structures, participating in anti-tumor immune responses. Notch and TGF-β signaling pathways synergistically regulate the differentiation of DP CD8+ TRM cells.ConclusionsWe clarified the roles and mechanisms of different CD8+ TRM subsets in CRC and identified that DP CD8+ TRM cells exert stronger anti-tumor effects and predict better prognosis, which provides ideas for developing new clinically available therapeutic targets.

Galacto-oligosaccharides alone and combined with lactoferrin impact the Kenyan infant gut microbiota and epithelial barrier integrity during iron supplementation in vitro

Aim: Iron supplementation to African weaning infants was associated with increased enteropathogen levels. While cohort studies demonstrated that specific prebiotics inhibit enteropathogens during iron supplementation, their mechanisms remain elusive. Here, we investigated the in vitro impact of galacto-oligosaccharides (GOS) and iron-sequestering bovine lactoferrin (bLF) alone and combined on the gut microbiota of Kenyan infants during low-dose iron supplementation. Methods: Different doses of iron, GOS, and bLF were first screened during batch fermentations (n = 3), and the effect of these factors was studied on microbiota community structure and activity in the new Kenyan infant continuous intestinal PolyFermS model. The impact of different fermentation treatments on barrier integrity, enterotoxigenic Escherichia coli (ETEC) infection, and inflammatory response was assessed using a transwell co-culture of epithelial and immune cells. Results: A dose-dependent increase in short-chain fatty acid (SCFA) production, Bifidobacterium and Lactobacillus /Leuconostoc /Pediococcus (LLP) growth was detected with GOS alone and combined with bLF during iron supplementation in batches. This was confirmed in the continuous PolyFermS model, which also showed a treatment-induced inhibition of opportunistic pathogens C. difficile and C. perfringens . In all tests, supplementation of iron alone and combined with bLF did not have a significant effect on microbiota composition and activity. We observed a strengthening of the epithelial barrier and a decrease in cell death and pro-inflammatory response during ETEC infection with microbiota fermentation supernatants from iron + GOS, iron + bLF, and iron + GOS + bLF treatments compared to iron alone. Conclusion: Overall, beneficial effects on infant gut microbiota were shown using advanced in vitro models for GOS alone and combined with bLF during low-dose iron supplementation.

TGF-β3 Restrains Osteoclastic Resorption Through Autophagy.

While TGF-β3 promoted defect healing in a primate baboon skull defect model and patients, it remains unclear whether TGF-β3 affects the formation of osteoclasts and bone resorption between osteogenesis and osteolysis. Analysis of the full transcriptome of hPDLSCs (human periodontal ligament stem cells) revealed that the expression of RANKL was significantly up-regulated after TGF-β3 treatment during osteogenesis, which suggests its involvement in clock-controlled autophagy in bone metabolism. TRAP staining and bone resorption lacunae were used to assess the osteoclasts formed from RANKL-induced differentiated BMMs. During osteoclast differentiation, the characteristics of autophagy regulated by TGF-β3 were observed in BMMs through MDC staining, transmission electron microscopy, and LC3 immunofluorescence. The expression of related genes and proteins were detected on the sixth day in mCherry-EGFP-LC3B lentivirus-transfected BMMs using RT-qPCR and WB. Finally, a trans-well co-culture system was used to evaluate the effects of osteogenic differentiated hPDLSCs treated with TGF-β3 on the osteoclastic differentiation of BMMs. The results showed 10 ng/mL of TGF-β3 significantly suppressed osteoclastic differentiation and bone resorption in BMMs (p < 0.05 vs. RANKL). In particular, TGF-β3 augments the expression of LC3-II to stimulate autophagy, consequently restraining osteoclastic resorption. These findings provide a molecular basis and are beneficial to illustrate the potential druggability of TGF-β3 in osteoporotic diseases.

Exosomes from Limosilactobacillus fermentum Ameliorate Benzalkonium Chloride-Induced Inflammation in Conjunctival Cells.

Dry eye is characterized by persistent instability and decreased tear production, which are accompanied by epithelial lesions and inflammation on the surface of the eye. In our previous paper, we reported that supplementation with Limosilactobacillus fermentum HY7302 (HY7302) could inhibit corneal damage in a benzalkonium chloride (BAC)-induced mouse model of dry eye, through its effects in gut microbiome regulation. The aim of this study was to determine what functional extracellular substances can alter the inflammatory response of conjunctival cells. We isolated exosomes from HY7302 probiotic culture supernatant, analyzed their morphological characteristics, and found that their average size was 143.8 ± 1.1 nm, which was smaller than the exosomes from the L. fermentum KCTC 3112 strain. In addition, HY7302-derived exosomes significantly reduced the levels of genes encoding pro-inflammatory cytokines, including interleukin (IL)-20, IL-8, IL-6, and IL-1B, in BAC-treated human conjunctival cells. Moreover, HY7302-derived exosomes significantly increased the levels of genes encoding tight junction proteins, including TJP1, TJP2, and occludin-1, in Caco-2 cells. Lastly, the HY7302 exosomes reduced mRNA expression levels of IL1B, IL20, IL6, IL8, and NFAT5 in a transwell coculture system. Our findings indicate that HY7302 exosomes have potential for use in the treatment of ocular inflammation-related dry eye disease, through gut-eye axis communication via exosomes.

Fibroblast growth factor 10 alleviates LPS-induced acute lung injury by promoting recruited macrophage M2 polarization.

Acute lung injury (ALI) is characterized by damage to the alveoli and an overabundance of inflammation. Representing a serious inflammatory condition, ALI lacks a precise treatment approach. Despite the recognized benefit impacts of Fibroblast growth factor-10 (FGF10) on ALI, the underlying mechanisms remain unelucidated. To study the role of FGF10 in ALI, C57BL/6J mice were intratracheally injected with 5mg/kg Lipopolysaccharide (LPS) with FGF10 (5mg/kg) or an equal volume of PBS. Inflammatory factors were quantified in bronchoalveolar lavage fluid (BALF) and plasma using ELISA. RNA sequencing of F4/80+Ly6G- macrophages in BALF explored changes in macrophage phenotype and potential mechanisms. Macrophage polarization in BALF was assessed using qRT-PCR, flow cytometry, and Western blot analysis. In vitro, a Transwell co-culture of mouse lung epithelial cells (MLE12) and bone marrow macrophages (BMDM) validated the role of FGF10 in modulating LPS-induced macrophage phenotypic changes. FGF10 ameliorated LPS-induced ALI by diminishing pro-inflammatory factors (IL-1β, TNF-α, and IL-6) and the neutrophil accumulation in BALF. FGF10 also increased the levels of anti-inflammatory factor IL-10. The FGF10 intervention group exhibited enhanced gene expression of macrophage arginine biosynthesis marker (ARG1), and expression of M2-type marker CD206 in monocytes and macrophages. In addition, phosphorylated STAT3 expression increased in isolated monocyte-derived macrophages. Experiments in vitro confirmed that FGF10 could elevate macrophage M2 marker ARG1 expression through the JAK2/STAT3 pathway. FGF10 ameliorates acute LPS-induced lung injury by modulating the polarization of monocyte-derived macrophages recruited in the alveolar space to the M2 type.

Abstract B022: Characterizing invasiveness in CCCR cells: Role of miR-100, miR-125b and EVs

Abstract Introduction: Extracellular vesicles have been found to be important regulators of intercellular communication between cancer cells. EV cargo varies greatly between different cell types, the composition of which provides important insights into the role of donor and recipient cells. Cetuximab Resistant Colorectal Cancer (CCCR) cells upregulate miR-100 and miR-125b and select them as cargo for their respective secreted EVs. These miRNAs are responsible for altered gene expression in the CCCR cells and can also be functionally transferred as part of EVs between donor and recipient cells. Bioinformatic analysis identified Cingulin (CGN) mRNA as one of the possible targets of miR-100 and miR-125b. The action of miRNAs leads to degradation of CGN mRNA ultimately decreasing cellular concentration of the functional protein. Absence of CGN has been associated with increased invasiveness and metastatic potential in the cancer cells. We carried out immunofluorescent imaging of CCCR cells which revealed downregulation of CGN in CCCR cells compared to the parental Cetuximab sensitive Colorectal Cancer (CC) cells. Similar effects were observed in recipient cells that obtained the miRNAs as part of EVs originating from CCCR donor cells. This project helps elucidate the roles of miR-100 and miR-125b in CCCR cells and how EVs facilitate their functional transfer between nearby cancer cells. Methods: CCCR cell lines were derived from parental CC cells in the lab of Dr. Robert Coffey by iterative selection of cetuximab resistance after growth in 3D. CRISPR/Cas9 technology was used to knockout miR-100 and miR-125b in CCCR cells. Transwell co-culture experiments were carried out to analyze EV transfer of miRNAs. Transfer was monitored by immunofluorescence using antibodies against CGN. Cells were stained and imaged as Z stacks under the 63x Immersion setting. ImageJ was used to analyze the stacks and CGN concentrations between the cells. For quantification of immunofluorescence, additional Z stack images were obtained from an inverted microscope and fluorescence digital camera. Images were analyzed using Fiji software to obtain specific CGN concentrations between the cells. Results and Discussion: Immunofluorescent imaging revealed statistically significant downregulation of CGN in CCCR cells. The protein was also downregulated in the recipient knockout cells as part of the Transwell co-culture experiment with CCCR donor cells. CGN is a tight junction protein and its absence confers increased invasiveness in 3D growth with enhanced metastasis. Decreased CGN concentration in the miR-100 and miR-125b enriched EV recipient knockout cells is indicative of functional transfer of the two miRNAs between cancer cells. These distinctive cellular dynamics could be harnessed to develop potential cancer therapies that provide a better prognosis and limit the metastatic potential of targeted cancer cells. Citation Format: Muhammad Shameer, Hannah M Nelson, Shimian Qu, Liyu Huang, Kevin C Corn, Sydney N Chapman, Nicole L Luthcke, Sara A Schuster, Tellie D Stamaris, Lauren A Turnbull, Lucas L Guy, Xiao Liu, Danielle L Michell, Elizabeth M Semler, Kasey C Vickers, Qi Liu, Jeffrey L Franklin, Alissa M Weaver, Marjan Rafat, Robert J Coffey, James G Patton. Characterizing invasiveness in CCCR cells: Role of miR-100, miR-125b and EVs [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr B022.

TMIC-25. MICROGLIA IN THE GLIOBLASTOMA MICROENVIRONMENT SECRETE ACETYLATED AMINO ACIDS WHICH ASSIST IN THE REPAIR OF RADIATION INDUCED DNA DAMAGE

Abstract Rapid repair of DNA damage mediates genotoxic therapy resistance and poor prognosis in glioblastoma (GBM). The GBM tumor microenvironment (TME) is heterogenous, and we hypothesized that non-malignant cells support the repair of DNA damage in glioblastoma cells. Consistent with this hypothesis, we found that GBM tumors grown intracranially in mice had rapid DNA repair and were resistant to radiation compared to tumors of identical genotype grown extracranially in mouse flanks. Further interrogation of irradiated intracranial tumors using gamma-H2AX immunofluorescence revealed spatial heterogeneity in DNA damage repair, with spatially separate regions of rapid and slow gamma-H2AX resolution. Paired spatial transcriptomic analysis and gamma-H2AX immunofluorescence showed that tumor regions with rapid DNA repair were rich in microglia. Having nominated microglia from these results, we cocultured GBM cells and microglia in direct contact as well as in transwell coculture. We found that GBM cells cocultured with microglia repair DNA damage faster in a contact-independent manner. We then assessed the supernatant metabolome of microglia and GBM monocultures and cocultures and found that acetylated amino acids are secreted by microglia and consumed by GBM cells. Supplementation with acetylated amino acids promotes radiation resistance by speeding the repair of radiation-induced DNA damage. Mechanistically, acetylated amino acid supplementation allows glioma cells to re-route glucose utilization away from the TCA cycle and towards nucleotide synthesis. Hence, we show that microglia in the GBM microenvironment assist GBM cells to repair radiation induced DNA damage by secreting acetylated amino acids which are consumed by GBM cells and used to fuel the TCA cycle allowing utilization of glucose for nucleotide synthesis, thereby making the GBM cells resistant to radiation therapy.

TMET-09. SEX-BIASED ROLE OF TUMOR-ASSOCIATED MACROPHAGES IN GLIOBLASTOMA IRON METABOLISM

Abstract Glioblastoma (GBM) is an aggressive brain cancer that is extremely difficult to treat. GBM is sexually dimorphic in nature, where females are less susceptible to developing GBM, respond to therapy better, and get a survival advantage. Sex-biased differences in tumor iron metabolism play a significant part in making this disease sexually dimorphic. Macrophages constitute a significant population in the GBM tumor microenvironment and are key players in tumor iron homeostasis. Here, we examine macrophage iron homeostasis as a potential driver of sex biases in glioblastoma using bone marrow-derived macrophages (BMDM) isolated from C57BL/6 mice. Immunoblot analysis revealed higher ferritin L-chain (FTL) expression in male BMDM than in females (Fold change: 3.18, P = 0.02). Flow cytometric analysis revealed that male BMDMs had a significantly higher labile iron pool (LIP) (Fold change: 1.62, P = 0.0081). We used a stable isotope of iron (Fe57) to determine macrophage iron uptake by ICP-MS, and observed that male BMDMs have a higher iron uptake (fold change: 1.623, P = 0.0018) than females. These results indicate that macrophage iron metabolism is sexually dimorphic in nature. Next, we used a transwell co-culture system to study how macrophages regulate the iron status of GL261 cells. We found that GL261 cells had significantly lower H-Ferritin (FTH1) expression when co-cultured with male BMDMs (Fold change: 0.789, P = 0.0045). However, this decrease in ferritin didn’t result in a decrease in cellular LIP. We discovered that there was an increase in secreted ferritin in the GL261 culture media. Further experiments with Fe57-loaded GBM cells showed that this increase in secreted ferritin correlated with increased iron release from the GL261 cells. These results indicate that tumor-associated macrophages may regulate tumor iron homeostasis by inducing ferritin-bound iron release from GBM cells in a sex-biased manner.

Nerve Growth Factor from Pancreatic Cancer Cells Promotes the Cancer Progression by Inducing Nerve Cell-Secreted Interleukin-6.

Pancreatic cancer (PC) is a cancer with a poor prognosis, and nerve growth factor (NGF) is involved in the pathogenesis of PC within the unknown exact role. Herein, SW1990 cells and PC12 cells were co-cultured using transwell co-culture system and subsequently revealed that NGF was overexpressed in SW1990 cells and promoted PC12 cell proliferation. Knockdown of NGF expression in SW1990 cells using lentiviral shRNA effectively inhibited NGF expression in SW1990 cells and reduced its stimulatory effect on PC12 cell proliferation. Additionally, NGF in SW1990 cells increased the expression of IL-6, dopamine, and c-FOS, as well as decreased the level of lactate dehydrogenase, in PC12 cells, whereas the inhibition of NGF expression significantly reduced the levels of IL-6, dopamine and c-FOS, indicating the critical role of IL-6/STAT3 signaling in PC progression. Finally, cell proliferation, migration, and invasion were assessed using cell counting kit-8, scratch, and Transwell assays, which showed that activated neurons promoted the proliferation, migration, invasion, and NGF secretion of SW1990 cells through the IL-6/STAT3 pathway. The results revealed that NGF secreted by PC cells played a pivotal role in PC progression via regulating activated neural cells-secreted IL-6, providing new theoretical insights for the treatment of PC.

Expression of soluble guanylate cyclase (sGC) and its ability to form a functional heterodimer are crucial for reviving the NO-sGC signaling in PAH

In order to determine the underpinnings of a dysfunctional NO-sGC signal pathway which occurs in pulmonary arterial hypertension (PAH), we investigated pulmonary arterial smooth muscle cells (PASMCs) derived from PAH patients. We found low expression of sGC, a poor sGCα1β1 heterodimer and this correlated with low expression of its facilitator chaperon, hsp90. Treating PASMCs overnight (16 h) with low micromolar doses of a slow release NO donor DETANONOate, reinstated the sGCα1β1 heterodimer and restored its NO-heme dependent activity. Transwell co-culture of HEK cells stably expressing eNOS with PAH PASMCs also restored the sGC heterodimer and its heme-dependent activity with sGC stimulator, BAY 41–2272. To determine whether the dysfunctionality in the NO-sGC pathway stems from a dysfunctional eNOS producing negligible NO, we did transwell co-cultures of pulmonary arterial endothelial cells (PAECs) with PASMCs. Our results indicated that PAECs from both control and PAH samples when activated for eNOS restored both sGC heterodimer and its heme-dependent sGC activity in the corresponding PASMCs, suggesting that PAECs from PAH can also generate NO. In line with these results expression of eNOS, its support chaperon hsp90, its specific kinase Akt, p-Akt or post-translational modifications (PTMs) like OGlcNAc or phospho-tyrosine were unchanged in PAH relative to controls. Additionally there was uniform expression of Hbα/β and Mb in PASMCs or PAECs in PAH or controls and these globins can effectively scavenge the eNOS generated NO, as there was evidence of strong eNOS-Hb/Mb interactions. Our studies suggest that factors such as globin NO scavenging along with vascular remodeling in PAH can cause hampered vasodilation which in the face of poor NO levels as occurs in PAH are additional impediments for effective vasodilation. However importantly our studies suggests that future therapies can use low doses of NO along with sGC stimulators as a potential drug for PAH subjects.

Synergistic effects of human umbilical cord mesenchymal stem cells/neural stem cells and epidural electrical stimulation on spinal cord injury rehabilitation

Spinal cord injury (SCI) is a severe neurological condition marked by a complex pathology leading to irreversible functional loss, which current treatments fail to improve. Epidural electrical stimulation (EES) shows promise in alleviating pathological pain, regulating hemodynamic disturbances, and enhancing motor function by modulating residual interneurons in the lower spinal cord. Cell transplantation (CT), especially using human umbilical cord mesenchymal stem cells (hUCMSCs) and neural stem cells (NSCs), has significantly improved sensory and motor recovery in SCI. However, the limitations of single treatments have driven the exploration of a multifaceted strategy, combining various modalities to optimize recovery at different stages. To comprehensively investigate the effectiveness of in situ transplantation of hUCMSCs/NSCs combined with subacute epidural electrical stimulation in a murine spinal cord crush injury model, providing valuable references for future animal studies and clinical research. In this study, we first examined neural stem cell changes via mRNA sequencing in an in vitro Transwell co-culture model. We then explored cell interaction mechanisms using proliferation assays, differentiation assays, and neuron complexity analysis. For animal experiments, 40 C57BL/6 mice were assigned to four groups (Injury/EES/CT/Combination). Histological evaluations employed HE and immunofluorescence staining, while electrophysiological and behavioral tests assessed motor recovery. Quantitative data were reported as mean ± standard error, with statistical analyses performed using GraphPad Prism and SPSS. Initially, we found that NSCs in the in vitro co-culture model showed a unique expression profile of differentially expressed genes (DEGs) compared to controls. GO/KEGG analysis indicated these DEGs were mainly linked to cell differentiation and growth factor secretion pathways. Neuronal and astrocytic markers further confirmed enhanced NSC differentiation and neuronal maturation in the co-culture model. In vivo, live imaging and human nuclei immunofluorescence staining revealed that transplanted cells persisted for some time post-transplantation. Histological analysis showed that during acute inflammation, both the stem cell and combined therapy groups significantly inhibited microglial polarization. In the chronic phase, these groups reduced fibrotic scar formation and encouraged astrocytic bridging. Behavioral tests, including swimming and gait analysis, demonstrated that combined CT and EES therapy was more effective than either treatment alone. In summary, the combined therapy offers a promising approach for spinal cord injury treatment, providing superior outcomes over individual treatments. Our findings underscore the potential of a combined treatment approach utilizing stem cells transplantation and EES as an effective strategy for the comprehensive management of spinal cord crush injury in mice. This integrated approach holds promise for enhancing functional recovery and improving the quality of life for individuals with spinal cord injury (SCI).

Overexpression of SLAP2 inhibits triple-negative breast cancer progression by promoting macrophage M1-type polarization

Breast cancer is the most common malignant tumor in women, and triple-negative breast cancer (TNBC) is a specific subtype of breast cancer characterized by high invasiveness, high metastatic potential, ease of recurrence, and poor prognosis. Src-like adaptor protein 2 (SLAP2), which can be involved in the regulation of multiple signaling pathways, may be a key target for TNBC. The aim of this study was to investigate the effect of overexpression of SLAP2 on TNBC and to explore the underlying mechanisms. First, we constructed and transfected SLAP2 overexpressing lentivirus based on MDA-MB-231 human TNBC cell line, screened for differential downstream target genes in combination with mRNA high-throughput sequencing (RNA-Seq), and predicted their functions and enriched pathways in conjunction with bioinformatics analysis. The effects of SLAP2 overexpression on macrophage polarization, as well as on tumor proliferation and apoptosis, were assessed by tail vein injection of a stable transfection line of 4T1 cells transfected with SLAP2 overexpressing lentivirus. The effect of SLAP2 on macrophage polarization was assessed by inducing M1/M2 polarization and transfecting SLAP2 overexpressing lentivirus. Meanwhile, a transwell co-culture system was constructed between differently treated macrophages and 4T1 cells to assess the effect of SLAP2 overexpression on the malignant behavior of the cells via macrophage polarization. Overexpression of SLAP2 revealed 179 genes up-regulated and 74 genes down-regulated by mRNA high-throughput sequencing, and the enriched functions and pathways of differential genes were mainly related to immunity response. In vivo experiments revealed that overexpression of SLAP2 inhibited the growth of tumor in nude mice, decreased the expression of ki67 in tumor tissues, and increased the rate of apoptosis in tumor tissues. Meanwhile, we found that overexpression of SLAP2 promoted macrophage polarization toward M1 type and inhibited M2 type polarization in tumors. In vitro experiments further verified its effect on M1/M2 polarization by transfecting SLAP2 overexpressing lentivirus. By transwell co-culture system, we further demonstrated that overexpression of SLAP2 inhibits cell proliferation and invasion, promotes apoptosis, up-regulates the expression of Bax in cells, and down-regulates the expression of Bcl-2 in cells by promoting macrophage M1-type polarization. Overexpression of SLAP2 inhibits TNBC progression by promoting macrophage M1-type polarization.

Promotion of Epithelial Healing in Oral Mucositis by hESC-Derived Mesenchymal Stem Cells via the PI3K/AKT Pathway

Introduction: Oral mucositis (OM) is a common and debilitating side effect of cancer therapies such as radiotherapy, chemotherapy, hematopoietic cell transplant, or their combinations. Method: This study focused on the reparative effects of human embryonic stem cell-derived mesenchymal stem cells (hESC-MSCs) in OM and possible mechanisms. An ulcer model was created in the rat buccal mucosa to mimic an in vivo animal model of OM mucosal injury, and hESC-MSCs were injected 48h later to assess their reparative effects. In vitro, the efficacy of hESC-MSCs in regulating apoptosis and proliferation in LPS- or 5-fluorouracil (5-FU)-injured HaCaT cells was studied using a transwell coculture system. Subsequently, the PI3K inhibitor LY24002 was used to assess whether hESC-MSCs regulated injured HaCaT cells through the PI3K/AKT pathway. In vivo, we found that hESC-MSCs injection promoted OM healing in rats through the acceleration of re-epithelialization and a decrease in apoptosis. Results: In vitro, our findings revealed that the hESC-MSCs treatment led to a reduction in the quantity of HaCaT cells undergoing apoptosis. Western blot analysis revealed that hESC-MSCs activated AKT, resulting in increased protein levels of PCNA and BCL-2 and decreased protein levels of Bax and Caspase-3 whereas LY294002 reversed these changes. Conclusion: These findings suggest that hESC-MSCs promoted OM wound healing by stimulating the proliferation of epithelial cells and inhibiting their apoptosis in rat models. Furthermore, hESC-MSCs might mediate the PI3K/AKT pathway to modulate apoptosis/proliferation injured by LPS or 5-FU in HaCaT cells.