Non-contact Co-culture System Research Articles

Indirect co-culture of osteoblasts and endothelial cells in vitro based on a biomimetic 3D composite hydrogel scaffold to promote the proliferation and differentiation of osteoblasts.

The field of orthopedics has long struggled with the challenge of repairing and regenerating bone defects, which involves a complex process of osteogenesis requiring coordinated interactions among different types of cells. The crucial role of endothelial cells and osteoblasts in bone vascularization and osteogenesis underscores the importance of their intimate interaction. However, efforts to bioengineer bone tissue have been impeded by the difficulty in establishing proper angiogenesis and osteogenesis in tissue structures. This study presents a novel approach to bone tissue engineering, involving a three-dimensional composite hydrogel scaffold composed of sodium alginate microspheres encapsulated in type I collagen. Using this scaffold, a three-dimensional indirect co-culture system was established for osteoblasts and endothelial cells to evaluate the osteogenic differentiation potential of osteoblasts. Results demonstrate that the non-contact co-culture system of endothelial cells and osteoblasts constructed by the composite hydrogel scaffold loaded with microspheres holds promise for bone tissue engineering. The innovative concept of an indirect co-culture system presents exciting prospects for conducting intercellular communication studies and offers a valuable in vitro tissue platform to investigate tissue regeneration.

Interspecies metabolite transfer fuels the methionine metabolism of Fusobacterium nucleatum to stimulate volatile methyl mercaptan production.

The major oral odor compound methyl mercaptan (CH3SH) is strongly associated with halitosis and periodontitis. CH3SH production stems from the metabolism of polymicrobial communities in periodontal pockets and on the tongue dorsum. However, understanding of CH3SH-producing oral bacteria and their interactions is limited. This study aimed to investigate CH3SH production by major oral bacteria and the impact of interspecies interactions on its generation. Using a newly constructed large-volume anaerobic noncontact coculture system, Fusobacterium nucleatum was found to be a potent producer of CH3SH, with that production stimulated by metabolic interactions with Streptococcus gordonii, an early dental plaque colonizer. Furthermore, analysis of extracellular amino acids using an S. gordonii arginine-ornithine antiporter (ArcD) mutant demonstrated that ornithine excreted from S. gordonii is a key contributor to increased CH3SH production by F. nucleatum. Further study with 13C, 15N-methionine, as well as gene expression analysis, revealed that ornithine secreted by S. gordonii increased the demand for methionine through accelerated polyamine synthesis by F. nucleatum, leading to elevated methionine pathway activity and CH3SH production. Collectively, these findings suggest that interaction between S. gordonii and F. nucleatum plays a key role in CH3SH production, providing a new insight into the mechanism of CH3SH generation in oral microbial communities. A better understanding of the underlying interactions among oral bacteria involved in CH3SH generation can lead to the development of more appropriate prophylactic approaches to treat halitosis and periodontitis. An intervention approach like selectively disrupting this interspecies network could also offer a powerful therapeutic strategy.IMPORTANCEHalitosis can have a significant impact on the social life of affected individuals. Among oral odor compounds, CH3SH has a low olfactory threshold and halitosis is a result of its production. Recently, there has been a growing interest in the collective properties of oral polymicrobial communities, regarded as important for the development of oral diseases, which are shaped by physical and metabolic interactions among community participants. However, it has yet to be investigated whether interspecies interactions have an impact on the production of volatile compounds, leading to the development of halitosis. The present findings provide mechanistic insights indicating that ornithine, a metabolite excreted by Streptococcus gordonii, promotes polyamine synthesis by Fusobacterium nucleatum, resulting in a compensatory increase in demand for methionine, which results in elevated methionine pathway activity and CH3SH production. Elucidation of the mechanisms related to CH3SH production is expected to lead to the development of new strategies for managing halitosis.

PD-L1 overexpression induces STAT signaling and promotes the secretion of pro-angiogenic cytokines in non-small cell lung cancer (NSCLC)

BackgroundMonoclonal antibodies (ICI) targeting the immune checkpoint PD-1/PD-L1 alone or in combination with chemotherapy have demonstrated relevant benefits and established new standards of care in first-line treatment for advanced non-oncogene addicted non-small cell lung cancer (NSCLC).However, a relevant percentage of NSCLC patients, even with high PD-L1 expression, did not respond to ICI, highlighting the presence of intracellular resistance mechanisms that could be dependent on high PD-L1 levels. The intracellular signaling induced by PD-L1 in tumor cells and their correlation with angiogenic signaling pathways are not yet fully elucidated. MethodsThe intrinsic role of PD-L1 was initially checked in two PD-L1 overexpressing NSCLC cells by transcriptome profile and kinase array. The correlation of PD-L1 with VEGF, PECAM-1, and angiogenesis was evaluated in a cohort of advanced NSCLC patients. The secreted cytokines involved in tumor angiogenesis were assessed by Luminex assay and their effect on Huvec migration by a non-contact co-culture system. ResultsPD-L1 overexpressing cells modulated pathways involved in tumor inflammation and JAK-STAT signaling. In NSCLC patients, PD-L1 expression was correlated with high tumor intra-vasculature. When challenged with PBMC, PD-L1 overexpressing cells produced higher levels of pro-angiogenic factors compared to parental cells, as a consequence of STAT signaling activation. This increased production of cytokines involved in tumor angiogenesis largely stimulated Huvec migration. Finally, the addition of the anti-antiangiogenic agent nintedanib significantly reduced the spread of Huvec cells when exposed to high levels of pro-angiogenic factors. ConclusionsIn this study, we reported that high PD-L1 modulates STAT signaling in the presence of PBMC and induces pro-angiogenic factor secretion. This could enforce the role of PD-L1 as a crucial regulator of the tumor microenvironment stimulating tumor progression, both as an inhibitor of T-cell activity and as a promoter of tumor angiogenesis.

Integrated metabolomic and lipidomic analysis revealed the protective mechanisms of Erzhi Wan on senescent NRK cells through BRL cells

Ethnopharmacological relevanceErzhi Wan (EZW), as a prescription of traditional Chinese medicine, has been used for tonifying the liver and kidney. Although past studies have shown that EZW has potential anti-aging effect, the mechanisms associated with cellular metabolomics and lipidomics are not fully understood. Aim of the studyThis study aimed to evaluate the anti-aging effect of EZW and investigate the mechanisms associated with cellular metabolomics and lipidomics. Materials and methodsEZW solution at dosage of 3.6 g/kg in Sprague-Dawley rats was orally administered twice a day for 7 days and serum containing EZW was then collected. NRK cell senescence model induced by D-galactose was established in vitro, and non-contact co-culture cell assay was performed between senescent NRK cells and BRL cells intervened by serum containing EZW. The anti-aging effect of EZW on NRK cells was evaluated by metabolites identification, differential metabolites screening and metabolic pathways analysis through cellular metabolomics with GC-MS and lipidomics with UHPLC-Q-Exactive Orbitrap/MS. ResultsSerum containing EZW indicated a protective effect through intervening BRL cells in non-contact co-culture system with D-gal-induced senescent NRK cells. For metabolic profiles, 71 endogenous metabolites were identified, among which 24 significantly differential metabolites were screened as metabolomics potential biomarkers. For lipidic profiles, 64 lipid components were identified in NRK cell samples under positive ion mode, among which 24 potential biomarkers of lipids were screened, mainly including PC and PE. 127 lipid components were identified in NRK cell samples under negative ion mode, among which 59 potential biomarkers of lipids were screened, including FA, PC, PE, PI and PS. Metabolic pathway analysis demonstrated that the identified differential metabolites found mainly involved in amino acids metabolism, energy metabolism and phospholipid biosynthesis pathways. ConclusionSerum containing EZW exhibited protective effect on D-gal-induced senescent NRK cells through intervening BRL cells by mainly regulating amino acids metabolism, energy metabolism and phospholipid biosynthesis pathways to possess its anti-aging function, providing a theoretical basis for clinical treatment of EZW.

Rab27a-mediated extracellular vesicle secretion contributes to osteogenesis in periodontal ligament-bone niche communication

Periodontitis, an infectious and common disease worldwide, leads to the destruction of the periodontal ligament-alveolar bone complex. Within the bone metabolic niche, communication between periodontal ligament stem cells (PDLSCs) and bone marrow mesenchymal stem cells (BMMSCs) has been considered a major contributor to osteogenesis. PDLSC-derived extracellular vesicles (P-EVs) have shown great potential for bone regeneration. However, the secretion and uptake mechanisms of P-EVs remain elusive. Herein, the biogenesis of extracellular vesicles (EVs) from PDLSCs was observed using scanning and transmission electron microscopy. PDLSCs were transduced with Ras-associated protein 27a (Rab27a) siRNA (PDLSCsiRab27a) to inhibit EV secretion. The effect of P-EVs on BMMSCs was evaluated using a non-contact transwell co-culture system. We observed that Rab27a knockdown decreased EV secretion, and PDLSCsiRab27a remarkably attenuated co-culture-enhanced osteogenesis of BMMSCs. Isolated PDLSC-derived EVs enhanced osteogenic differentiation of BMMSCs in vitro and induced bone regeneration in a calvarial defect model in vivo. PDLSC-derived EVs were rapidly endocytosed by BMMSCs via the lipid raft/cholesterol endocytosis pathway and triggered the phosphorylation of extracellular signal-regulated kinase 1/2. In conclusion, PDLSCs contribute to the osteogenesis of BMMSCs through Rab27a-mediated EV secretion, thereby providing a potential cell-free approach for bone regeneration.

DMP1 POSITIVE ASTROCYTES MAINTAIN BLOOD-BRAIN BARRIER VIA TRANSFERRING MITOCHONDRIA TO VASCULAR ENDOTHELIAL CELLS

Though dentin matrix protein 1 (Dmp1) is known to play critical role in mediating bone mineralization, it has also been validated to be expressed in brain and helps maintain blood brain barrier (BBB). Our study aims to clarify the expression pattern of Dmp1 in mouse brain and explore whether intercellular mitochondrial transfer occurs between Dmp1 positive astrocytes (DPAs) and endothelial cells, and thus acting as a mechanism in maintaining BBB during aging.Single cell RNA sequencing (scRNAseq) of 1 month, 6 month, and 20 month old mice brain (n=1, respectively) was employed to identify Dmp1 positive cell types. Dmp1Cre-mGmT and Dmp1Cre-COX8a fluorescent mice were generated to visualize DPAs and investigate their mitochondrial activities. A 3D noncontact coculture system and mitochondrial transplantation were applied to study the role of mitochondrial transfer between astrocytes and bEnd.3 endothelial cells. Dmp1Cre-Mfn2f/f mice were generated by depleting the ER-mitochondria tethering protein Mfn2 in DPAs.Dmp1 was mainly expressed in astrocytes at different ages. GO analysis revealed that cell projection and adhesion of DPAs were upregulated. Confocal imaging on Dmp1Cre-mGmT mice indicated that DPAs are a cluster of astrocytes that closely adhere to blood vessels (n=3). Bioinformatics analysis revealed that mitochondrial activity of DPAs were compromised during aging. Enriched scRNAseq of fluorescent cells from Dmp1Cre-COX8a mice (n=2) and immunofluorescent imaging (n=3) validated the acquisition of extrinsic mitochondria in endothelial cells. 3D coculture of astrocytes and bEnd.3 and direct mitochondrial transplantation revealed the rescue effect of mitochondrial transfer on damaged bEnd.3. BBB was impaired after depleting Mfn2 in DPAs, expressing a similar phenotype with aging brain.Astrocytes that express Dmp1 play a significant role in maintaining BBB via transferring mitochondria to vascular endothelial cells. Compromised mitochondrial transfer between DPAs and endothelial cells might be the potential mechanism of impaired BBB during aging.

Exosomes derived from M1 macrophages inhibit the proliferation of the A549 and H1299 lung cancer cell lines via the miRNA-let-7b-5p-GNG5 axis.

Almost all cells are capable of secreting exosomes (Exos) for intercellular communication and regulation. Therefore, Exos can be used as a natural therapeutic platform to regulate genes or deliver drugs to treat diseases. M1 macrophages inhibit tumor growth by releasing pro-inflammatory factors. This study explored the applicability of M1 macrophage exosomes (M1-Exos) as gene carriers and the effects on GNG5 protein, and further examined whether macrophage repolarization could inhibit tumor activity. M0 macrophages were polarized toward M1 using vitexin. Exos were obtained from M1 macrophages by ultra-centrifugation. The transwell non-contact co-culture system was used to co-culture M1 macrophages with HLF-α human lung epithelial cells or A549 or H1299 lung cancer cells. MTT, scratch, and transwell assays were used to detect the cell viability, migration, and invasion ability of cells in the four groups. Flow cytometry was used to detect the apoptosis rate of each group, and western blot (WB) analysis was performed to detect the change in the expression of proliferation- and apoptosis-related proteins. We screened the differentially expressed microRNAs using quantitative polymerase chain reaction technology. Luciferase reporter analysis was performed to explore the interaction between miRNA and protein. We used Xenografted A549 tumors in nude mice to study the effect of M1-Exos on tumor cell growth in vivo. The results showed that, under the M1 macrophage co-culture system, lung cancer cell viability, invasion, and migration ability decreased, and the number of apoptotic cells increased, will all indicators being statistically significant (P<0.05). The expression levels of PCNA, KI67, and Bcl-2 decreased significantly, but that of Bax increased (P<0.05). Exosomes can have the same effect on tumor cells as M1 macrophages. Exosomes can transport miR-let-7b-5p to tumor cells, and miR-let-7b-5p can inhibit tumor cell proliferation and promote tumor cell apoptosis by regulating the GNG5 protein level. M1-Exos inhibit the proliferation, invasion, and metastasis of lung cancer cells through miRNA-let-7b-5p and GNG5 signaling pathways and inhibit the anti-apoptotic ability of lung cancer cells.

M2-TAMs promote immunoresistance in lung adenocarcinoma by enhancing METTL3-mediated m6A methylation.

Immunotherapy has become the first-line treatment for advanced non-small-cell lung cancer (NSCLC), but most patients still fail to benefit or have disease progression following treatment. M2 phenotype tumor-associated macrophages (M2-TAMs) are important cellular components in the immunosuppressive microenvironment of NSCLC, but how they contribute to immunoresistance remains unclear. This study was conducted to investigate the role and mechanism of M2-TAMs in NSCLC immunoresistance. We collected postoperative tumor samples for detection of M2-TAMs and other immune cells infiltration by immunofluorescence detection and flow cytometry. We then constructed a non-contact cell co-culture system using Transwell chambers. CCK-8, colony formation, wound healing and invasion assays were performed to evaluated the effect of M2-TAMs on the proliferation, migration and invasion abilities of lung adenocarcinoma (LUAD) cells in vitro. Xenograft model were performed to analysis the effect of M2-TAMs on the tumorigenesis and metastasis of LUAD cells in vivo. M2-TAMs were greatly increased in the tumor tissue of patients with immunoresistant LUAD. They could significantly promote the proliferation, invasion, and migration of LUAD cells, and improve their resistance to cytotoxic T lymphocytes (CTL) cytotoxicity. Further research showed M2-TAMs could considerably enhance the expression of METTL3 and total m6A RNA level in LUAD cells and interfering with METTL3 could significantly reverse the impairment of M2-TAMs on the efficacy of CTL in killing tumor cells. In conclusion, M2-TAMs could promote LUAD immunoresistance by enhancing METTL3-mediated m6A methylation. Our results suggest METTL3 could be a potential therapeutic target for reversing immunoresistance and shed new light on the mechanism of M2-TAMs promoting LUAD immunoresistance.

Overexpression of interleukin-10 in engineered macrophages protects endothelial cells against LPS-induced injury in vitro.

Endothelial dysfunction is a primary pathophysiological change in sepsis. Macrophages are known to interact with vascular endothelial cells during the development of sepsis. Recently, drug delivery based on engineered macrophages was reported as an alternative approach for the management of diseases. Interleukin‐10 (IL10) is a well‐known anti‐inflammatory cytokine, which reduces inflammation and inhibits dysfunction of endothelial cells caused by sepsis. It is currently poorly understood whether genetically modified macrophages with overexpression of IL10 are able to restore endothelial integrity and function at the cellular level. In this study, we used lentiviral vectors to construct RAW264.7 macrophages engineered to overexpress IL10 (IL10‐eM) and investigated the effects of the IL10‐eM supernatant on LPS‐induced endothelial dysfunction using a noncontact coculture system. We found that cotreatment with IL10‐eM supernatant significantly attenuates the effects of LPS‐induced dysfunction of endothelial cells, including endothelial inflammatory response, endothelial permeability, and apoptosis. In addition, we discovered that LPS‐induced downregulation of VE‐cadherin and high production of reactive oxygen species were significantly attenuated upon IL10‐eM exposure. Furthermore, upregulation of IL6, TNFα, and Bax was decreased after treatment of cells with IL10‐eM supernatant. These results demonstrated that supernatant from engineered macrophages genetically modified with IL10 can effectively protect endothelial cells against LPS‐induced dysfunction in vitro, suggesting that exosomes from such engineered macrophages may have therapeutic effects against sepsis.

Spermatozoa induce transcriptomic alterations in bovine oviductal epithelial cells prior to initial contact

The capability of spermatozoa to directly influence maternal gene expression is already established. Indeed, some of the changes induced by spermatozoa may have a direct functional importance in the pre-conceptional period. Although the mechanisms underlying these sperm-maternal interactions are not well characterized, it is possible that they could involve ligands that are released from the spermatozoa. This study therefore aimed to test whether physical contact between bovine spermatozoa and bovine oviductal epithelial cells (BOECs) is a prerequisite for spermatozoa-induced gene expression changes. We used two co-culture models: a contact co-culture model in which spermatozoa interact directly with BOECs, and a non-contact co-culture model in which an insert with the pore size of 0.4 μm was placed between spermatozoa and BOECs. Messenger RNA sequencing analysis of BOECs by RNA-seq revealed ten differentially expressed genes in contact system and 108 differentially expressed genes in the non-contact system after 10 h of co-culture. Retinol metabolism pathway and ovarian steroidogenesis pathway were significantly enriched in the non-contact co-culture system. Q-PCR analysis revealed that transcriptional responses can be rapid, with increased expression of four genes (DHRS3, CYP1B1, PTGS2, and ATF3) detectable within just 90 min of co-incubation, but with expression levels highly dependent on the type of co-culture system. The findings from our study demonstrate that direct contact with spermatozoa is not necessary to induce changes in gene expression of oviductal epithelial cells, suggesting that spermatozoa may be able to signal to maternal tissues in advance of their arrival.

3D Printing of Cell-Container-Like Scaffolds for Multicell Tissue Engineering

The development of an engineered non-contact multicellular coculture model that can mimic the in vivo cell microenvironment of human tissues remains challenging. In this study, we successfully fabricated a cell-container-like scaffold composed of β-tricalcium phosphate/hydroxyapatite (β-TCP/HA) bioceramic that contains four different pore structures, including triangles, squares, parallelograms, and rectangles, by means of three-dimensional (3D) printing technology. These scaffolds can be used to simultaneously culture four types of cells in a non-contact way. An engineered 3D coculture model composed of human bone-marrow-derived mesenchymal stem cells (HBMSCs), human umbilical vein endothelial cells (HUVECs), human umbilical vein smooth muscle cells (HUVSMCs), and human dermal fibroblasts (HDFs) with a spatially controlled distribution was constructed to investigate the individual or synergistic effects of these cells in osteogenesis and angiogenesis. The results showed that three or four kinds of cells cocultured in 3D cell containers exhibited a higher cell proliferation rate in comparison with that of a single cell type. Detailed studies into the cell–cell interactions between HBMSCs and HUVECs revealed that the 3D cell containers with four separate spatial structures enhanced the angiogenesis and osteogenesis of cells by amplifying the paracrine effect of the cocultured cells. Furthermore, the establishment of multicellular non-contact systems including three types of cells and four types of cells, respectively, cocultured in 3D cell containers demonstrated obvious advantages in enhancing osteogenic and angiogenic differentiation in comparison with monoculture modes and two-cell coculture modes. This study offers a new direction for developing a scaffold-based multicellular non-contact coculture system for tissue regeneration.

A peroxisome deficiency–induced reductive cytosol state up-regulates the brain-derived neurotrophic factor pathway

The peroxisome is a subcellular organelle that functions in essential metabolic pathways, including biosynthesis of plasmalogens, fatty acid β-oxidation of very-long-chain fatty acids, and degradation of hydrogen peroxide. Peroxisome biogenesis disorders (PBDs) manifest as severe dysfunction in multiple organs, including the central nervous system (CNS), but the pathogenic mechanisms in PBDs are largely unknown. Because CNS integrity is coordinately established and maintained by neural cell interactions, we here investigated whether cell-cell communication is impaired and responsible for the neurological defects associated with PBDs. Results from a noncontact co-culture system consisting of primary hippocampal neurons with glial cells revealed that a peroxisome-deficient astrocytic cell line secretes increased levels of brain-derived neurotrophic factor (BDNF), resulting in axonal branching of the neurons. Of note, the BDNF expression in astrocytes was not affected by defects in plasmalogen biosynthesis and peroxisomal fatty acid β-oxidation in the astrocytes. Instead, we found that cytosolic reductive states caused by a mislocalized catalase in the peroxisome-deficient cells induce the elevation in BDNF secretion. Our results suggest that peroxisome deficiency dysregulates neuronal axogenesis by causing a cytosolic reductive state in astrocytes. We conclude that astrocytic peroxisomes regulate BDNF expression and thereby support neuronal integrity and function.

Early oral nutrition improves postoperative ileus through the TRPA1/CCK1-R-mediated mast cell-nerve axis.

BackgroundThe mechanism of early oral nutrition that regulates the mast cell-nerve axis to improve postoperative ileus (POI) remains unclear. This study aims to investigate whether early oral nutrition can improve POI through Transient receptor potential ankyrin-1 (TRPA1)/cholecystokinin 1 receptor (CCK1-R) in the mast cell-nerve axis.MethodsExperiment 1: Male Sprague-Dawley (SD) rats were randomly divided into the TRPA1 inhibitor + oral nutrition group (TI + ON + POI), oral nutrition group (ON + POI), POI group (POI) and sham surgery group (Sham). Nine rats in each group were treated. Experiment 2: Primary cultures of mast cells and dorsal root ganglion cells were created, and a non-contact co-culture system was established. The cells were divided into the dorsal root ganglion (DRG) group, mast cell group, DRG + mast cell group, TRPA1 inhibitor or enhancer group, mast cell stabilizer or enhancer group, CCK1-R inhibitor or enhancer group. The results of expression of TRPA1, CCK1-R and histamine in colon tissue, portal vein blood, supernatant or dorsal root ganglia, intestinal transport test and mast cell morphology were analysed.ResultsIn experiment 1, Early oral nutrition could alleviate the degranulation and activation of mast cells and alleviate the inflammatory reaction of intestinal wall muscles (P<0.05). Early oral nutrition improved POI by stabilizing mast cells with TRPA1. TRPA1 inhibitor decreased CCK1-R concentrations in portal vein blood and CCK1-R expression in colonic smooth muscle (P<0.05). In experiment 2, the change in mast cell function regulated the secretion of CCK1-R by neurons, CCK1-R negatively regulated the degranulation and activation of mast cells (P<0.05), and mast cells positively regulated the expression of TRPA1 protein in DRG (P<0.05).ConclusionsEarly enteral nutrition can improve POI through the TRPA1/CCK1-R-mediated mast cell-nerve axis. TRPA1 positively regulates CCK1-R to stabilize mast cells, but TRPA1 is not the target of the downstream CCK1-R pathway.

Soluble factors mediate the interaction between Schwann cells and osteocytes

ObjectiveRegenerating loss of bone and nerve tissue is a serious concern among oral and maxillofacial surgeons, yet there is little information regarding the connection between bone metabolism and the nervous system. This study aimed to obtain evidence of this connection. MethodsOsteocyte and Schwann cell lines were maintained in a non-contact co-culture system. Quantitative reverse-transcription polymerase chain reactions, immunoblot analyses, and cell proliferation assays were performed. The dendrite length of osteocytes was analyzed quantitatively. ResultsThe dendrite length of osteocytes co-cultured with Schwann cells was significantly increased and associated with E11 protein expression. Schwann cell culture supernatant inhibited osteocyte proliferation and promoted dendrite elongation. However, myelin basic protein in Schwann cells was upregulated in the presence of osteocyte culture supernatant without changes in proliferation and dendrite extension. Schwann cells express the Sema3A gene and co-culture with osteocytes enhanced Sema3A mRNA expression. ConclusionsOur data suggest that Schwann cells promote osteocyte maturation via humoral factors including Sema3A and osteocytes regulate myelination of Schwann cells.

Protective effect of human umbilical cord mesenchymal stem cells on light-damaged retinal pigment epithelial cells

Objective To investigate the protective effect of human umbilical cord mesenchymal stem cells (UCMSCs) on light-damaged retinal pigment epithelial (RPE) cells in vitro. Methods Human UCMSCs were cultured, and then identified by flow cytometry.Human RPE cells were isolated and cultured, and then the model of light-damaged RPE cells was prepared.The noncontact co-culture system of light-damaged RPE cells and UCMSCs was established by Transwell chamber.RPE cells were divided into normal control group, model control group and UCMSCs co-culture group.RPE cells in the normal control group were not treated.RPE cells in the model control group were treated with blue light to induce RPE cell damage.Co-culture system of light-damaged RPE cells and UCMSCs was established in the UCMSCs co-culture group.The proliferative ability of RPE cells was measured by methyl thiazolyl tetrazolium (MTT) assay at 24 hours and 48 hours after co-culture.ELISA kits were used to quantitatively measure the levels of pigment epithelium-derived factor (PEDF) and basic fibroblast growth factor (bFGF) in the culture supernatant at 48 hours after co-culture.And the photoreceptor outer segments (POS) phagocytosis assay of RPE cells was also conducted. Results UCMSCs displayed spindle-shaped morphology, positively expressed CD29, CD44, CD90 and CD105, while negatively expressed CD34 and CD45.RPE cells were polygonal in morphology and positive for the specific marker RPE65 protein.The proliferative ability(A value) of RPE cells in the three groups at different timepoints were significantly different (Fgroup=132.388, P=0.000; Ftime=231.440, P=0.000), the A values of RPE cells in model control group and UCMSCs co-culture group were significantly lower than that in the normal control group, the A value of RPE cells in UCMSCs co-culture group was significantly higher than that in the model control group, and the differences were statistically significant both at 24 hours and 48 hours after co-culture (all at P<0.01). POS phagocytosis test showed that there was a significant difference in the average number of POS particles phagocytized by RPE cells among the three groups(F=28.087, P=0.000). The average number of POS particles phagocytized by RPE cells in model control group was significantly lower than that in normal control group, and the average number of POS particles phagocytized by RPE cells in UCMSCs co-culture group was significantly more than that in model control group (all at P<0.01). ELISA showed that the concentrations of PEDF in RPE cell supernatant of normal control group, model control group and UCMSCs co-culture group were (18.8±1.9), (10.0±1.7) and (20.2±6.0)ng/ml, respectively.The concentrations of bFGF in RPE cell supernatant were (25.2±1.5), (26.3±3.6) and (61.9±14.3)pg/ml, respectively.There were significant differences in PEDF and bFGF concentrations among the three groups (F=8.654, P=0.008; F=23.698, P=0.000). The concentration of PEDF in the model control group was significantly lower than that in the normal control group, and the concentration of PEDF in the UCMSCs co-culture group was significantly higher than that in the model control group (all at P<0.01). The concentration of bFGF in UCMSCs co-culture group was significantly higher than that in the normal control group and model control group (all at P<0.01). Conclusions Cocultivation with UCMSCs can improve the proliferation ability and phagocytosis function of light-damaged RPE cells, and promote the secretion of PEDF by RPE cells.UCMSCs may protect RPE cells from light damage through paracrine secretion of bFGF. Key words: Retina; Umbilical cord mesenchymal stem cells; Light damage; Retinal pigment epithelial cells; Neurotrophic effect

Prostatic epithelial cells and their high expressions of CKIP-1 affect the TGF-\u03b21 expression levels which might reduce the scar formation in remodeling stage at prostatic urethral wounds after wound repair

ObjectiveThere are less scar formations in some wounds after wound repair. Our earlier study had shown that the amount of collagen fibers in canine prostatic urethra wound were less than in bladder neck wound after 2-μm laser resection of the prostate (TmLRP) and partial bladder neck mucosa at 4 weeks. The purpose of this study was to observe the amount of scar tissue and characterize the probable causes of “less scar healing” in prostatic urethra wound.MethodsA total of 12 healthy adult male crossbred canines underwent resection of prostate and partial bladder neck mucosa using 2-μm laser. The prostatic urethra and bladder neck wound specimens were harvested at 3, 4, 8 and 12 weeks after operation, respectively. The histopathologic characteristics were observed by hematoxylin and eosin(HE)staining, and the expression of transforming growth factor-β1 (TGF-β1) and casein kinase-2 interacting protein-1 (CKIP-1) were examined by immunohistochemistry in prostatic urethra and bladder neck wound, respectively. Overexpressed CKIP-1 human prostate epithelial cells (BPH-1 cells) were established and the expression of TGF-β1 was detected by Western blotting. Furthermore, a non-contact co-culture system of BPH-1 cells and human fibroblast (HFF-1) cells was used to observe the effects of BPH-1 cell and their high CKIP-1 levels on the expression of TGF-β1 in HFF-1 in vitro.ResultsThe histology showed that there were a large number of prostatic epithelium and a small amount of scar tissue in prostatic urethra wound, while no epithelial cells and more scar tissue in bladder neck wound at 4, 8 and 12 weeks after repair. There were a higher expression level of TGF-β1 in prostate epithelial cells and fibroblasts and a lower expression level of CKIP-1 in prostate epithelial cells at 3 weeks after surgery in prostatic urethral wound. Compared to week 3, the TGF-β1 expression decreased both in prostate epithelial cells and fibroblasts at 4, 8 and 12 weeks in prostatic urethral wound (p < 0.05 or p < 0.01). The CKIP-1 expression increased in prostate epithelial cells at 4, 8 and 12 weeks compared to 3 weeks in prostatic urethra wound (p < 0.01). A higher TGF-β1 expression level of fibroblasts was observed in bladder neck wound at 3 weeks. And there was no significant change in the expression of TGF-β1 of fibroblasts in 3, 4, 8 and 12 weeks after operation in bladder neck wound. Both the prostate urethra and bladder neck wound fibroblasts showed weak expression of CKIP-1 and there was no significant change in 3, 4, 8 and 12 weeks. The vitro experiments showed that the TGF-β1 expression in BPH-1 cells with CKIP-1 overexpression decreased 25% compared with control group (p < 0.05). Furthermore, the expression of TGF-β1 in HFF-1 cells of co-cultured group decreased by 20% compared with Control group (p < 0.05); the expression of TGF-β1 in HFF-1 cells of overexpression co-culture group were reduced by 15% compared with co-cultured group (p < 0.01).ConclusionsA large number of prostate epithelial cells in prostatic urethra wound may be one of the causes of less formation of scar tissue after repair. The prostate epithelial cells might reduce expression level of TGF-β1 by raising CKIP-1 expression and inhibit expression of TGF-β1 in peripheral fibroblasts at remodeling stage to reduce the excessive proliferation of fibrous cells and the excessive scar formation.

Abstract 4851: Involvement of extracellular vesicles in the abscopal effect induced by oncolytic adenovirotherapy

Abstract Background: The abscopal effect is a phenomenon that shrinkage of metastatic tumors occurs concurrently with shrinkage of primary tumors by local treatments such as radiotherapy, and is generally considered to be caused through activation of the immune system. Extracellular vesicles (EVs) are recent interesting topics in scientific fields and are known to play important roles in a variety of intercellular communication processes including immune response. We previously developed a telomerase specific oncolytic adenovirus, Telomelysin (OBP-301), which is currently being tested in clinical trials, and have sometimes observed therapeutic effects on metastatic tumors after local injection to primary tumors in immunodeficient mouse models. Here, we hypothesized that EVs derived from OBP-301-treated tumors may be associated with the abscopal effect of OBP-301. Methods: A human colon carcinoma cell line HCT116 and HCT116 expressing RFP (HCT116-RFP) were used in this study. EVs were isolated by ultracentrifugation from HCT116 cells treated with OBP-301 (Exo-301). Intercellular communication and cytotoxic activity via EVs after OBP-301 treatment were assessed in a non-contact co-culture system in vitro and a bilateral subcutaneous tumor mouse model in vivo. Results: Exo-301 showed potent cytotoxic effects on HCT116 cells and this cytotoxicity was significantly blocked in the presence of anti-CD9 antibody, which suggested that Exo-301, not OBP-301 itself, was involved in this cytotoxicity. In non-contact co-culture experiments, more RFP was taken up into HCT116 cells after OBP-301 treatment on HCT116-RFP cells than control treatments, which meant that EVs including RFP reached HCT116 cells through membrane after OBP-301 treatment on HCT116-RFP cells. In a HCT116 bilateral subcutaneous tumor model in BALB/c nude mice, intratumoral injection of OBP-301 significantly suppressed the growth of untreated tumors as well as treated tumors, and in a bilateral tumor model with HCT116 on one side and HCT116-RFP on the opposite side, immunohistochemical staining showed the presence of RFP in untreated HCT116 tumors after OBP-301 treatment on HCT116-RFP tumors. These findings suggested that EVs derived from OBP-301-treated tumors was possibly involved in some cytotoxic effects on the opposite untreated tumors. Conclusion: EVs may be an important factor in the abscopal effect brought by local treatment of OBP-301 besides immune activation. Citation Format: Yoshihiko Kakiuchi, Shinji Kuroda, Nobuhiko Kanaya, Kento Kumon, Tomoko Tsumura, Satoru Kikuchi, Masahiko Nishizaki, Shunsuke Kagawa, Hiroshi Tazawa, Yasuo Urata, Toshiyoshi Fujiwara. Involvement of extracellular vesicles in the abscopal effect induced by oncolytic adenovirotherapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4851.

Effects of transplanted adipose derived stem cells on the expressions of α-SMA and DCN in fibroblasts of hypertrophic scar tissues in rabbit ears.

To study the effects of transplanted adipose derived stem cells (ADSCs) on the expressions of α-smooth muscle actin (α-SMA) and decorin (DCN) in fibroblasts of hypertrophic scar tissues in rabbit ears. Twelve New Zealand white rabbits were selected; the normal subcutaneous adipose tissues in inguinal region were removed, ADSCs were extracted via enzyme digestion, cultured in Dulbecco's modified Eagle's medium (DMEM) and inoculated into the culture dish (3–5×104 cells/ml). After the rabbit ear hypertrophic scar model was established successfully, the fibroblasts of hypertrophic scar tissues in rabbit ears were separated and cultured using the mechanical method combined with enzyme digestion, and the ADSCs and scar fibroblasts were cultured in non-contact Transwell co-culture system for 21 days (experimental group); the corresponding scar fibroblasts were cultured in an ordinary 6-well plate without any treatment for 21 days (control group). The content of collagen I in fibroblasts was detected using the enzyme-linked immunosorbent assay (ELISA) kit, the mRNA expressions of α-SMA and DCN were detected via reverse transcription-polymerase chain reaction (RT-PCR), the protein expressions of α-SMA and DCN were detected via western blot analysis, and the expressions and distribution of α-SMA and DCN were detected via immunofluorescence assay. The results of ELISA showed that the content of collagen I in experimental group was decreased significantly (p<0.01). The results of RT-PCR and western blot analysis revealed that the mRNA and protein expression levels of α-SMA were significantly decreased (P<0.01, but those of DCN were significantly increased (p<0.01). Moreover, the results of immunofluorescence assay showed that the expression of α-SMA in experimental group was significantly decreased, while the expression of DCN was significantly increased. ADSCs can inhibit the mRNA and protein expressions of α-SMA and promote the mRNA and protein expressions of DCN in in vitro culture system, and they are expected to be used in the prevention and treatment of pathological scars.

Non-contact Coculture Reveals a Comprehensive Response of Chondrocytes Induced by Mesenchymal Stem Cells Through Trophic Secretion.

Coculture between mesenchymal stem cells (MSCs) and chondrocytes has significant implications in cartilage regeneration. However, a conclusive understanding remains elusive. Previously, we reported that rabbit bone marrow-derived MSCs (rbBMSCs) could downregulate the differentiated phenotype of rabbit articular chondrocytes (rbACs) in a non-contact coculture system for the first time. In the present study, a systemic investigation was performed to understand the biological characteristics of chondrocytes in coculture with MSCs. Firstly, cells (MSCs and chondrocytes) from different origins were cocultured in transwell system. Different chondrocytes, when cocultured with different MSCs respectively, consistently demonstrated stimulated proliferation, transformed morphology and declined glycosaminoglycan secretion of chondrocytes. Next, cell surface molecules and the global gene expression of rbACs were characterized. It was found that cocultured rbACs showed a distinct surface molecule profile and global gene expression compared to both dedifferentiated rbACs and rbBMSCs. In the end, cocultured rbACs were passaged and induced to undergo the chondrogenic redifferentiation. Better growth and chondrogenesis ability were confirmed compared with control cells without coculture. Together, chondrocytes display comprehensive changes in coculture with MSCs and the cocultured rbACs are beneficial for cartilage repair.

The Crosstalk between HDPSCs and HUCMSCs on Proliferation and Osteogenic Genes Expression in Coculture System.

Objectives: The present study established a non-contact coculture system in vitro, aiming to investigate the crosstalk between human dental pulp stem cells (hDPSCs) and human umbilical cord mesenchymal stem cells (hUCMSCs) on proliferation activity and osteogenic genes expression through paracrine.Materials and methods: The stemness of hDPSCs and hUCMSCs were identified by flow cytometric analysis and multipotential differentiation assays. With the help of transwell inserts, the non-contact coculture system in vitro was established between hDPSCs and hUCMSCs. EdU labeling analysis and Western Blot were used to detect the proliferation activity. The mRNA and protein levels of osteogenic genes were evaluated by RT-PCR and Western Blot. The expression of elements in Akt/mTOR signaling pathway were detected by Western Blot.Results: Both hDPSCs and hUCMSCs were positive to MSCs specific surface markers and had multi-differentiation potential. The proportion of EdU-positive cells increased and the expression of CDK6 and CYCLIN A were up-regulated in cocultured hDPSCs. Both prior coculture and persistent coculture improved mRNA and protein levels of osteogenic genes in hDPSCs. While in cocultured hUCMSCs, no statistical differences were observed on proliferation and osteogenesis. The phosphorylation of Akt and mTOR was up-regulated in cocultured hDPSCs.Conclusions: The crosstalk between hDPSCs and hUCMSCs in coculture system increased the proliferation activity and enhanced osteogenic genes expression in hDPSCs. Akt/mTOR signaling pathway might take part in the enhancing effects in both cell proliferation and gene expression.