Cobblestone Morphology Research Articles

Abstract B008: Alternative PER2 (Period2) enhancer usage drives epithelial-mesenchymal transition (EMT) in epithelial ovarian cancer (OC)

Abstract B008: Alternative <i>PER2</i> (Period2) enhancer usage drives epithelial-mesenchymal transition (EMT) in epithelial ovarian cancer (OC)

Approaches to induce the maturation process of human induced pluripotent stem cell derived-endothelial cells to generate a robust model.

Endothelial cells generated from induced pluripotent stem cells (hiPSC-ECs) show the majority of endothelial cell characteristics and markers, such as cobblestone morphology and the expression of VEGF and VE-cadherin. However, these cells are failing to show a mature endothelial cell phenotype, which is represented by the low expression and production of von Willebrand Factor (VWF) leading to the round morphology of the Weibel Palade Bodies (WPBs). The aim of this study was to improve the maturation process of hiPSC-ECs and to increase the levels of VWF. hiPSC-ECs were differentiated by a standard differentiation protocol from hiPSCs generated from healthy control donors. To induce maturation, the main focus was to increase the expression and/or production of VWF by the adjustment of potential parameters influencing differentiation and maturation. We also compared alternative differentiation protocols. Cells were analyzed for the expression of endothelial cell markers, WPB structure, and the production and secretion of VWF by flow cytometry, confocal microscopy and ELISA. The generated hiPSC-ECs have typical endothelial cell surface expression profiles, with low expression levels of non-endothelial markers as expected. Co-culture with pericytes, varying concentrations and timing of differentiation factors, applying some level of flow, and the addition of HDAC inhibitors did not substantially improve maturation of hiPSC-ECs. Transfection with the transcription factor ETV2 to induce a faster hiPSC-EC differentiation process resulted in a limited increase in VWF production, secretion, and elongation of WPB structure. Alternative differentiation protocols had limited effect. hiPSCs-ECs have the potential to show a more mature endothelial phenotype with elongated WPBs after >30 days in culture. However, this comes with limitations as there are very few cells detected, and cells are deteriorating after being in culture for extended periods of time.

Clinically compliant cryopreservation of differentiated retinal pigment epithelial cells

Background aimsAge-related macular degeneration (AMD) is the most common cause of blindness in elderly patients within developed countries, affecting more than 190 million worldwide. In AMD, the retinal pigment epithelial (RPE) cell layer progressively degenerates, resulting in subsequent loss of photoreceptors and ultimately vision. There is currently no cure for AMD, but therapeutic strategies targeting the complement system are being developed to slow the progression of the disease. MethodsReplacement therapy with pluripotent stem cell-derived (hPSC) RPEs is an alternative treatment strategy. A cell therapy product must be produced in accordance with Good Manufacturing Practices at a sufficient scale to facilitate extensive pre-clinical and clinical testing. Cryopreservation of the final cell product is therefore highly beneficial, as the manufacturing, pre-clinical and clinical testing can be separated in time and location. ResultsWe found that mature hPSC-RPE cells do not survive conventional cryopreservation techniques. However, replating the cells 2–5 days before cryopreservation facilitates freezing. The replated and cryopreserved hPSC-RPE cells maintained their identity, purity and functionality as characteristic RPEs, shown by cobblestone morphology, pigmentation, transcriptional profile, RPE markers, transepithelial resistance and pigment epithelium–derived factor secretion. Finally, we showed that the optimal replating time window can be tracked noninvasively by following the change in cobblestone morphology. ConclusionsThe possibility of cryopreserving the hPSC-RPE product has been instrumental in our efforts in manufacturing and performing pre-clinical testing with the aim for clinical translation.

The Root Extracts of Valeriana Officinalis L. may Control Programmed Cell Death Pathways in Breast Cancer Cell Line, MCF-7

Natural product-derived phytochemicals are now accepted as promising agents in developing new strategies for cancer treatment and prevention. The root extracts of valerian (Valeriana officinalis L.), which is a supplement widely used for improving circadian rhythm-dependent sleep disorders and insomnia, might be a good candidate in that context. In the present study we hypothesized whether extract of valerian root induce programmed cell death machineries in a human breast cancer model, MCF-7 cells. To test the hypothesis, we treated MCF-7 cells with the extract at different concentrations for 24 h. Giemsa staining was used to evaluate the apoptotic morphology and apoptotic index, and monodancylcadaverine assay was used to determine vacuoles that are associated with autophagic flux. Our results indicated that extracts of the roots of valerian have apototic and autophagic effect on human breast cancer cell MCF-7 in a dose dependent manner. Moreover, the typical cobblestone morphology of the cells was disrupted after the extract treatments and the cells lost contact with each other. This morphological alteration was attributed to anoikis, is a programmed cell death type induced by loss of cell communication with extracellular matrix or neighboring cells. In conclusion, although this study has many methodological shortcomings, our findings suggest that Valeriana officinalis L. might be a potential anti-cancer agent for the treatment of breast cancer.

Abstract 14923: Induced Pluripotent Stem Cell Derived Endothelial Progenitor Cells Attenuate Pulmonary Arterial Hypertension

Introduction: Although transplantation of adult endothelial progenitor cells (EPCs) holds promise in the treatment for pulmonary arterial hypertension (PAH), the low number and weakened functions of human primary EPCs are serious problems for autologous transplantation for patients and limited their therapeutic efficiency. Hypothesis: Te aim of this study is to investigate the efficiency of induced pluripotent stem cell derived EPCs on attenuating PAH. Methods: This study differentiated induced pluripotent stem cells from healthy people into vascular endothelial precursor cells (iPSC-EPC), whose specific protein expressed CD133 accounted for 95.4% and KDR accounted for 75.7%, and further confirmed that iPSC-EPC have the ability to differentiate vascular endothelial cells (iPSC-EC) with similar EC cobblestone morphology, acetylated LDL uptake, and UEA-1 lectin binding. IPSC-EC-specific protein expression CD144 accounts for 99.0% and CD31 accounts for 75.1%. Results: This study explored the efficacy of healthy iPSC-EPC in the treatment of PAH in an animal model. Both prophylactic and therapeutic treatments of iPSC-EPC were effective in rescuing monocrotaline (MCT)-induced right ventricular systolic pressure (RVSP), right ventricular hypertrophy, and pulmonary artery wall thickening in PAH. Pulmonary artery smooth muscle cells (PASMC) derived from MCT-treated rats (MCT-PASMC) developed more proliferative and pro-migratory phenotypes, which were attenuated by the iPSC-EPC derived culture medium (EPC-CM) treatment. Moreover, the proliferation and migration of MCT-PASMC were reduced by EPC-CM with suppression of PCNA, cyclin D1, MMP-1, and MMP-9. This study also found that iPSC-EPC treatment reduced MCT-PASMC senescence and senescence-associated secretory phenotype (SASP) in MCT-treated rats. Conclusions: This study found that ctrl iPSC-EPC restored miRNA levels in the lung tissue of MCT-treated rats. IPSC-EPC is effective at preventing and reversing pulmonary hypertension by regulating the expression of miRNAs, and reducing pulmonary vascular remodelling.

Increased Activated Protein C Response Rates to Thrombin Formation in Asymptomatic Factor V Leiden Carriers Are Driven By the Endothelium

Background The thrombophilic factor V Leiden (FVL) mutation shows a highly variable clinical expressivity. We have shown in vivo that asymptomatic FVL carriers respond to extrinsic coagulation activation with higher activated protein C (APC) formation rates than those with a history of venous thromboembolism (VTE). Recently we have established an ex vivo model for personalized assessment of the protein C (PC) pathway combining endothelial colony forming cells (ECFCs) and autologous plasma. Aim of this study was to investigate potential modulating factors of the APC response in the endothelium unraveling the enigma of the variable expressivity of the FVL phenotype. Methods ECFCs were isolated from FVL carriers with (FVL VTE+) or without (FVL VTE-) a history of unprovoked VTE and healthy controls (non-FVL) (n=7 each). Quality control of cultured cells included cobblestone morphology as examined by light microscopy, positive staining for CD31, CD309, CD201, and CD141, CD34, and negative staining for CD45 analyzed by flow cytometry. We either added autologous or pooled normal defibrinated plasma to the confluent cell culture and inititated thrombin formation by addition of tissue factor (1 pmol/L) and CaCl 2 (16.6 mmol/L) ( Fig. 1A). Thrombin and APC formation were measured over time using oligonucleotide-based enzyme capture assays (OECAs) and the ratio between the area under the curve (AUC) of APC formation and the AUC of thrombin formation was calculated as measure for APC response to thrombin. Moreover, we quantified thrombomodulin (TM) and endothelial protein C receptor (EPCR) expression in cell-based enzyme-linked immunosorbent assays (cell-ELISAs) and measured activation of purified PC on ECFCs in the APC-OECA. Results ECFC morphology in light microscopy and characteristic surface marker expression in flow cytometry did not differ between non-FVL, FVL VTE-, and FVL VTE+ subgroups. In the ECFC-based ex vivo model, the APC response in plasma on autologous cells was significantly higher in asymptomatic FVL VTE- carriers compared to non-FVL carriers (P = .0072) and compared to the FVL VTE+ subgroup (P = .0292) whereas it did not differ significantly between non-FVL and FVL VTE+ carriers. EPCR expression on ECFCs measured by cell-ELISA was higher in non-FVL carriers compared to FVL VTE+ subjects (P = .0374) but did not differ significantly when comparing non-FVL versus FVL VTE-, and FVL VTE+ versus FVL VTE-. Similarly, we showed that TM expression as well as activation of purified PC on ECFCs did not differ between cohorts. However, when the APC response was assessed on FVL VTE- and FVL VTE+ ECFCs using non-FVL plasma, the difference in the APC response between asymptomatic FVL carriers and FVL carriers with a history of VTE persisted (P = .0111) ( Fig. 1B). Conclusion Consistent with previous in vivo experiments, APC response rates to thrombin formation were increased on ECFCs obtained from asymptomatic FVL carriers compared to those from FVL carriers with a history of VTE in autologous plasma. Although TM and EPCR expression did not differ between both groups, we showed that the endothelial APC response in asymptomatic FVL carriers remained increased when using plasma from healthy controls. Our observations suggest that the increased APC response to thrombin in asymptomatic FVL carriers is driven by the endothelium. Further studies are warranted to elucidate the underlying mechanism for a better understanding of endogenous protective factors in FVL carriers. These findings may pave the way towards personalized, precision medicine approaches for managing the thrombotic risk in FVL and other disorders related to the PC pathway.

Smooth muscle cell-targeted RNA ligand promotes accelerated reendothelialization in a swine peripheral injury model

The local delivery of antiproliferative agents to inhibit neointimal growth is not specific to vascular smooth muscle cells (VSMC) and delays reendothelialization and vascular healing. This investigation was intended to evaluate the effect of luminal delivery of a VSMC-specific aptamer on endothelial healing. The impact of an RNA aptamer (Apt 14) was first examined on the migration and proliferation of primary cultured porcine aortic endothelial cells (ECs) in response to invitro scratch wound injury. We further evaluated the impact of Apt 14 on reendothelialization when delivered locally in a swine iliofemoral injury model. Although Apt 14 did not affect EC migration and proliferation, invitro results confirmed that paclitaxel significantly inhibited EC migration and proliferation. En face scanning electron microscopy demonstrated confluent endothelium with elongated EC morphology in Apt 14-treated arteries 14 and 28days post-treatment. In contrast, vessels treated with paclitaxel-coated balloons displayed a cobblestone morphology and significant platelet and fibrin attachment at cell junctions. These results provide the first evidence of the efficacy of a cell-targeted RNA aptamer to facilitate endothelial healing in a clinically relevant large animal model.

Abstract 461: Alcohol Modulates Chemokine- And Hypoxia-induced Endothelial-to-mesenchymal Transition In Vitro And Following Ligation Injury In Vivo

Endothelial-to-mesenchymal transition (EndMT) plays a role in arteriosclerotic cardiovascular disease (CVD). Low-to-moderate alcohol consumption (i.e., 1-3 drinks/d range) protects against endothelial dysfunction and arteriosclerosis, in part by stimulating Notch, but whether it does so by influencing EndMT is unknown. Our aim was to address this question. Human coronary artery endothelial cells (HCAEC) (p5-p14) were treated (7 d) with transforming growth factor β (TGFβ, 10 ng/ml) or exposed to hypoxia (5% O 2 ), in the absence or presence of ‘moderate’ level EtOH (25 mM), or the Notch ligand DLL4 +/- the Notch inhibitor DAPT. EndMT was assessed by determining endothelial marker CD31 and smooth muscle cell marker αSMA expression by immunohistochemistry and qRT-PCR, as well as by cell morphology and extracellular matrix protein Fibronectin production. Both TGFβ and hypoxia induced EndMT of HCAEC as determined by simultaneously decreased CD31 and increased αSMA expression, together with a change in morphology from cobblestone (typical of endothelial cells) to spindle-shaped (typical of mesenchymal cells), and increased fibronectin expression. EtOH inhibited EndMT caused by both TGFβ and hypoxia as indicated by maintenance of CD31 expression and cobblestone morphology, and attenuated αSMA and fibronectin expression in the EtOH treated group vs controls. Similar to EtOH, treatment with DLL4 inhibited TGFβ-induced myogenic αSMA and fibronectin mRNA expression in HCAEC, effects blocked by DAPT. Following carotid ligation in C57Bl/6 mice, ~25% of neointimal and medial cells in the remodeled vessel co-expressed αSMA and CD31 (indicative of myo-endothelial cells), suggesting the involvement of EndMT. In the ‘daily moderate’ alcohol group (2 drinks per day equivalent; peak BAC=15 mM) carotid neointimal hyperplasia was reduced compared to controls concomitant with fewer (&lt;10%) αSMA + /CD31 + myo-endothelial cells suggesting repression of EndMT in that cohort. In conclusion, these data illuminate an inhibitory effect of alcohol on EndMT, potentially mediated via Notch. This effect on endothelial transdifferentiation may underlie, in part, the protective effect of moderate alcohol consumption on CVD.

Human Saphenous Vein Endothelial Cell Isolation and Exposure to Controlled Levels of Shear Stress and Stretch.

Coronary artery bypass graft (CABG) surgery is a procedure to revascularize ischemic myocardium. Saphenous vein remains used as a CABG conduit despite the reduced long-term patency compared to arterial conduits. The abrupt increase of hemodynamic stress associated with the graft arterialization results in vascular damage, especially the endothelium, that may influence the low patency of the saphenous vein graft (SVG). Here, we describe the isolation, characterization, and expansion of human saphenous vein endothelial cells (hSVECs). Cells isolated by collagenase digestion display the typical cobblestone morphology and express endothelial cell markers CD31 and VE-cadherin. To assess the mechanical stress influence, protocols were used in this study to investigate the two main physical stimuli, shear stress and stretch, on arterialized SVGs. hSVECs are cultured in a parallel plate flow chamber to produce shear stress, showing alignment in the direction of the flow and increased expression of KLF2, KLF4, and NOS3. hSVECs can also be cultured in a silicon membrane that allows controlled cellular stretch mimicking venous (low) and arterial (high) stretch. Endothelial cells' F-actin pattern and nitric oxide (NO) secretion are modulated accordingly by the arterial stretch. In summary, we present a detailed method to isolate hSVECs to study the influence of hemodynamic mechanical stress on an endothelial phenotype.

HAI-1 is required for the novel role of FGFBP1 in maintenance of cell morphology and F-actin rearrangement in human keratinocytes.

Formation and maintenance of skin barrier function require tightly controlled membrane-associated proteolysis, in which the integral membrane Kunitz-type serine protease inhibitor, HAI-1, functions as the primary inhibitor of the membrane-associated serine proteases, matriptase and prostasin. Previously, HAI-1 loss in HaCaT human keratinocytes resulted in an expected increase in prostasin proteolysis but a paradoxical decrease in matriptase proteolysis. The paradoxical decrease in shed active matriptase is further investigated in this study with an unexpected discovery of novel functions of fibroblast growth factor-binding protein 1 (FGFBP1), which acts as an extracellular ligand that can rapidly elicit F-actin rearrangement and subsequently affect the morphology of human keratinocytes. This novel growth factor-like function is in stark contrast to the canonical activity of this protein through interactions with FGFs for its pathophysiological functions. This discovery began with the observation that HAI-1 KO HaCaT cells lose the characteristic cobblestone morphology of the parental cells and exhibit aberrant F-actin formation along with altered subcellular targeting of matriptase and HAI-2. The alterations in cell morphology and F-actin status caused by targeted HAI-1 deletion can be restored by treatment with conditioned medium from parental HaCaT cells, in which FGFBP1 was identified by tandem mass spectrometry. Recombinant FGFBP1 down to 1ng/ml was able to revert the changes caused by HAI-1 loss. Our study reveals a novel function of FGFBP1 in the maintenance of keratinocyte morphology, which depends on HAI-1.

Molecular and Functional Characteristics of Airway Epithelium under Chronic Hypoxia.

Localized and chronic hypoxia of airway mucosa is a common feature of progressive respiratory diseases, including cystic fibrosis (CF). However, the impact of prolonged hypoxia on airway stem cell function and differentiated epithelium is not well elucidated. Acute hypoxia alters the transcription and translation of many genes, including the CF transmembrane conductance regulator (CFTR). CFTR-targeted therapies (modulators) have not been investigated in vitro under chronic hypoxic conditions found in CF airways in vivo. Nasal epithelial cells (hNECs) derived from eight CF and three non-CF participants were expanded and differentiated at the air-liquid interface (26-30 days) at ambient and 2% oxygen tension (hypoxia). Morphology, global proteomics (LC-MS/MS) and function (barrier integrity, cilia motility and ion transport) of basal stem cells and differentiated cultures were assessed. hNECs expanded at chronic hypoxia, demonstrating epithelial cobblestone morphology and a similar proliferation rate to hNECs expanded at normoxia. Hypoxia-inducible proteins and pathways in stem cells and differentiated cultures were identified. Despite the stem cells' plasticity and adaptation to chronic hypoxia, the differentiated epithelium was significantly thinner with reduced barrier integrity. Stem cell lineage commitment shifted to a more secretory epithelial phenotype. Motile cilia abundance, length, beat frequency and coordination were significantly negatively modulated. Chronic hypoxia reduces the activity of epithelial sodium and CFTR ion channels. CFTR modulator drug response was diminished. Our findings shed light on the molecular pathophysiology of hypoxia and its implications in CF. Targeting hypoxia can be a strategy to augment mucosal function and may provide a means to enhance the efficacy of CFTR modulators.

Influence of Aerosolization on Endothelial Cells for Efficient Cell Deposition in Biohybrid and Regenerative Applications

The endothelialization of gas exchange membranes can increase the hemocompatibility of extracorporeal membrane oxygenators and thus become a long-term lung replacement option. Cell seeding on large or uneven surfaces of oxygenator membranes is challenging, with cell aerosolization being a possible solution. In this study, we evaluated the endothelial cell aerosolization for biohybrid lung application. A Vivostat® system was used for the aerosolization of human umbilical vein endothelial cells with non-sprayed cells serving as a control. The general suitability was evaluated using various flow velocities, substrate distances and cell concentrations. Cells were analyzed for survival, apoptosis and necrosis levels. In addition, aerosolized and non-sprayed cells were cultured either static or under flow conditions in a dynamic microfluidic model. Evaluation included immunocytochemistry and gene expression via quantitative PCR. Cell survival for all tested parameters was higher than 90%. No increase in apoptosis and necrosis levels was seen 24 h after aerosolization. Spraying did not influence the ability of the endothelial cells to form a confluent cell layer and withstand shear stresses in a dynamic microfluidic model. Immunocytochemistry revealed typical expression of CD31 and von Willebrand factor with cobble-stone cell morphology. No change in shear stress-induced factors after aerosolization was reported by quantitative PCR analysis. With this study, we have shown the feasibility of endothelial cell aerosolization with no significant changes in cell behavior. Thus, this technique could be used for efficient the endothelialization of gas exchange membranes in biohybrid lung applications.

Subretinal implantation of human primary RPE cells cultured on nanofibrous membranes in minipigs

AbstractThe development of primary human retinal pigmented epithelium (hRPE) for clinical transplantation purposes on biodegradable scaffolds is indispensable. The results of the subretinal implantation of hRPE cells on nanofibrous membranes in minipigs are hereby reported.The hRPEs were collected from human cadaver donor eyes and cultivated on ultrathin nanofibrous carriers prepared via the electrospinning of poly(L‐lactide‐co‐DL‐lactide) (PDLLA). “Libechov” minipigs (12–36 months old) were used in the study, supported by preoperative tacrolimus immunosuppressive therapy. The subretinal implantation of the hRPE‐nanofibrous carrier was conducted using general anaesthesia, followed by silicone oil endotamponade. The observational period lasted up to 8 weeks, and included in vivo optical coherence tomography (OCT) of the retina, as well as post mortem immunohistochemistry.The hRPEs assumed cobblestone morphology, persistent pigmentation and measurable trans‐epithelial electrical resistance on the nanofibrous PDLLA carrier. The implanted hRPEs were positive for HNAA and STEM121 (human cell markers) and were located between the minipig's neuroretina and RPE layers at week 2 post‐implantation, which was gradually attenuated until week 8. The neuroretina over the implants showed rosette or hypertrophic reaction at week 6. The implanted cells expressed the typical RPE marker bestrophin throughout the whole observation period, and a gradual diminishing of the CRALBP expression in the area of implantation at week 8 post‐implantation was observed. The transplanted hRPEs appeared not to form a confluent layer and were less capable of keeping the inner and outer retinal segments intact. The cone photoreceptors adjacent to the implant scaffold were unchanged initially, but underwent a gradual change in structure after hRPE implantation; the retina above and below the implant appeared relatively healthy. The glial reaction of the transplanted and host retina showed Vimentin and GFAP positivity from week 1 onward. Microglial activation appeared in the retinal area of the transplant early after the surgery, which seemed to move into the transplant area over time.Altogether, the differentiated hRPEs can serve as an alternative cell source for RPE replacement in animal studies. These cells can be cultivated on nanofibrous PDLLA and implanted subretinally into minipigs using standard 23‐gauge vitrectomy and implantation injector. The hRPE‐laden scaffolds demonstrated relatively good incorporation into the host retina over an eight‐week observation period, with some indication of a gliotic scar formation, and a likely neuroinflammatory response in the transplanted area despite the use of immunosuppression.

Neural, adipocyte and hepatic differentiation potential of primary and secondary hair follicle stem cells isolated from Arbas Cashmere goats

BackgroundArbas Cashmere goats are excellent domestic breeds with high yields of wool and cashmere. Their wool and cashmere can bring huge benefits to the livestock industry. Our studies intend to more fully understand the biological characteristics of hair follicle stem cells (HFSCs) in order to further explore the mechanisms of wool and cashmere regular regeneration. And they have been increasingly considered as promising multipotent cells in regenerative medicine because of their capacity to self-renew and differentiate. However, many aspects of the specific growth characteristics and differentiation ability of HFSCs remain unknown. This study aimed to further explore the growth characteristics and pluripotency of primary hair follicle stem cells (PHFSCs) and secondary hair follicle stem cells (SHFCs).ResultsWe obtained PHFSCs and SHFSCs from Arbas Cashmere goats using combined isolation and purification methods. The proliferation and vitality of the two types of HFSCs, as well as the growth patterns, were examined. HFSC-specific markers and genes related to pluripotency, were subsequently identified. The PHFSCs and SHFSCs of Arbas Cashmere goat have a typical cobblestone morphology. Moreover, the PHFSCs and SHFSCs express HFSC surface markers, including CD34, K14, K15, K19 and LGR5. We also identified pluripotency-associated gene expression, including SOX2, OCT4 and SOX9, in PHFSCs and SHFSCs. Finally, PHFSCs and SHFSCs displayed multipotent abilities. PHFSCs and SHFSCs can be directed to differentiate into adipocyte-like, neural-like, and hepatocyte-like cells.ConclusionsIn conclusion, this study confirmed that the biological characteristics and differentiation potential of PHFSCs and SHFSCs from Arbas Cashmere goats. These findings broaden and refine our knowledge of types and characteristics of adult stem cells.

Human umbilical cord mesenchymal stem cell-derived exosomal miR-335-5p attenuates the inflammation and tubular epithelial–myofibroblast transdifferentiation of renal tubular epithelial cells by reducing ADAM19 protein levels

BackgroundRenal tubular epithelial–myofibroblast transdifferentiation (EMT) plays a key role in the regulation of renal fibrosis. Exosomes derived from human umbilical cord mesenchymal stem cells (hucMSCs) play a crucial role in alleviating renal fibrosis and injury. Additionally, hucMSC-derived exosomes contain numerous microRNAs (miRNAs). However, it is unclear whether mesenchymal stem cells can regulate the transforming growth factor (TGF)-β1-induced EMT of human renal tubular epithelial cells (RTECs) through exosomal miRNAs.MethodHK-2, a human RTEC line, was co-treated with TGF-β1 and hucMSC-derived exosomes. Additionally, TGF-β1-treated HK-2 cells were transfected with a miR-335-5p mimic and disintegrin and metalloproteinase domain-containing protein 19 (ADAM19)-overexpression plasmid. miR-335-5p expression and ADAM19 protein and inflammation levels were measured via quantitative reverse transcription polymerase chain reaction, western blotting, and enzyme-linked immunosorbent assays, respectively.ResultsTGF-β1 treatment changed the shape of HK-2 cells from a cobblestone morphology to a long spindle shape, accompanied by an increase in interleukin (IL)-6, tumor necrosis factor-α, IL-1β, collagen I, collagen III, α-smooth muscle actin, vimentin, and N-cadherin protein levels, whereas E-cadherin protein levels were reduced in these HK-2 cells, suggesting that TGF-β1 treatment induced the inflammation and EMT of HK-2 cells. HucMSC-exosomes improved the inflammation and EMT phenotype of TGF-β1-induced HK-2 cells by transferring miR-335-5p. miR-335-5p was found to bind the ADAM19 3′-untranslated region to reduce ADAM19 protein levels. Additionally, miR-335-5p improved the inflammation and EMT phenotype of HK-2 cells by reducing ADAM19 protein levels with TGF-β1 induction.ConclusionsHucMSC-derived exosomal miR-335-5p attenuates the inflammation and EMT of HK-2 cells by reducing ADAM19 protein levels upon TGF-β1 induction. This study provides a potential therapeutic strategy and identifies targets for clinically treating renal fibrosis.

Development and Preliminary Testing of Porcine Blood-Derived Endothelial-like Cells for Vascular Tissue Engineering Applications: Protocol Optimisation and Seeding of Decellularised Human Saphenous Veins.

Functional endothelial cells (EC) are a critical interface between blood vessels and the thrombogenic flowing blood. Disruption of this layer can lead to early thrombosis, inflammation, vessel restenosis, and, following coronary (CABG) or peripheral (PABG) artery bypass graft surgery, vein graft failure. Blood-derived ECs have shown potential for vascular tissue engineering applications. Here, we show the development and preliminary testing of a method for deriving porcine endothelial-like cells from blood obtained under clinical conditions for use in translational research. The derived cells show cobblestone morphology and expression of EC markers, similar to those seen in isolated porcine aortic ECs (PAEC), and when exposed to increasing shear stress, they remain viable and show mRNA expression of EC markers similar to PAEC. In addition, we confirm the feasibility of seeding endothelial-like cells onto a decellularised human vein scaffold with approximately 90% lumen coverage at lower passages, and show that increasing cell passage results in reduced endothelial coverage.

Comparative studies between the murine immortalized brain endothelial cell line (bEnd.3) and induced pluripotent stem cell-derived human brain endothelial cells for paracellular transport.

Brain microvascular endothelial cells, forming the anatomical site of the blood-brain barrier (BBB), are widely used as in vitro complements to in vivo BBB studies. Among the immortalized cells used as in vitro BBB models, the murine-derived bEnd.3 cells offer culturing consistency and low cost and are well characterized for functional and transport assays, but result in low transendothelial electrical resistance (TEER). Human-induced pluripotent stem cells differentiated into brain microvascular endothelial cells (ihBMECs) have superior barrier properties, but the process of differentiation is time-consuming and can result in mixed endothelial-epithelial gene expression. Here we performed a side-by-side comparison of the ihBMECs and bEnd.3 cells for key paracellular diffusional transport characteristics. The TEER across the ihBMECs was 45- to 68-fold higher than the bEnd.3 monolayer. The ihBMECs had significantly lower tracer permeability than the bEnd.3 cells. Both, however, could discriminate between the paracellular permeabilities of two tracers: sodium fluorescein (MW: 376 Da) and fluorescein isothiocyanate (FITC)–dextran (MW: 70 kDa). FITC-dextran permeability was a strong inverse-correlate of TEER in the bEnd.3 cells, whereas sodium fluorescein permeability was a strong inverse-correlate of TEER in the ihBMECs. Both bEnd.3 cells and ihBMECs showed the typical cobblestone morphology with robust uptake of acetylated LDL and strong immuno-positivity for vWF. Both models showed strong claudin-5 expression, albeit with differences in expression location. We further confirmed the vascular endothelial- (CD31 and tube-like formation) and erythrophagocytic-phenotypes and the response to inflammatory stimuli of ihBMECs. Overall, both bEnd.3 cells and ihBMECs express key brain endothelial phenotypic markers, and despite differential TEER measurements, these in vitro models can discriminate between the passage of different molecular weight tracers. Our results highlight the need to corroborate TEER measurements with different molecular weight tracers and that the bEnd.3 cells may be suitable for large molecule transport studies despite their low TEER.

Subretinal Implantation of Human Primary RPE Cells Cultured on Nanofibrous Membranes in Minipigs.

Purpose: The development of primary human retinal pigmented epithelium (hRPE) for clinical transplantation purposes on biodegradable scaffolds is indispensable. We hereby report the results of the subretinal implantation of hRPE cells on nanofibrous membranes in minipigs. Methods: The hRPEs were collected from human cadaver donor eyes and cultivated on ultrathin nanofibrous carriers prepared via the electrospinning of poly(L-lactide-co-DL-lactide) (PDLLA). “Libechov” minipigs (12–36 months old) were used in the study, supported by preoperative tacrolimus immunosuppressive therapy. The subretinal implantation of the hRPE-nanofibrous carrier was conducted using general anesthesia via a custom-made injector during standard three-port 23-gauge vitrectomy, followed by silicone oil endotamponade. The observational period lasted 1, 2, 6 and 8 weeks, and included in vivo optical coherence tomography (OCT) of the retina, as well as post mortem immunohistochemistry using the following antibodies: HNAA and STEM121 (human cell markers); Bestrophin and CRALBP (hRPE cell markers); peanut agglutining (PNA) (cone photoreceptor marker); PKCα (rod bipolar marker); Vimentin, GFAP (macroglial markers); and Iba1 (microglial marker). Results: The hRPEs assumed cobblestone morphology, persistent pigmentation and measurable trans-epithelial electrical resistance on the nanofibrous PDLLA carrier. The surgical delivery of the implants in the subretinal space of the immunosuppressed minipigs was successfully achieved and monitored by fundus imaging and OCT. The implanted hRPEs were positive for HNAA and STEM121 and were located between the minipig’s neuroretina and RPE layers at week 2 post-implantation, which was gradually attenuated until week 8. The neuroretina over the implants showed rosette or hypertrophic reaction at week 6. The implanted cells expressed the typical RPE marker bestrophin throughout the whole observation period, and a gradual diminishing of the CRALBP expression in the area of implantation at week 8 post-implantation was observed. The transplanted hRPEs appeared not to form a confluent layer and were less capable of keeping the inner and outer retinal segments intact. The cone photoreceptors adjacent to the implant scaffold were unchanged initially, but underwent a gradual change in structure after hRPE implantation; the retina above and below the implant appeared relatively healthy. The glial reaction of the transplanted and host retina showed Vimentin and GFAP positivity from week 1 onward. Microglial activation appeared in the retinal area of the transplant early after the surgery, which seemed to move into the transplant area over time. Conclusions: The differentiated hRPEs can serve as an alternative cell source for RPE replacement in animal studies. These cells can be cultivated on nanofibrous PDLLA and implanted subretinally into minipigs using standard 23-gauge vitrectomy and implantation injector. The hRPE-laden scaffolds demonstrated relatively good incorporation into the host retina over an eight-week observation period, with some indication of a gliotic scar formation, and a likely neuroinflammatory response in the transplanted area despite the use of immunosuppression.

Novel Evidence That By Employing a Two-Step Differentiation Protocol in the Presence of UM171 and Nicotinamide Acid Human Very Small Embryonic like Stem Cells (VSELs) Differentiate into Functional Endothelial Cells (ECs)

Background. Human Very small embryonic-like stem cells (VSELs) are CD133 + CD34 + small dormant stem cells with properties of self-renewal and multipotential ability to differentiate in the three-germ layers (Circulation Research 2019; 124: 208-210) and currently, more than 40 independent groups worldwide who have carefully followed the multicolor-staining cell-sorting strategy described by us (Current Protocols in Cytometry 2010 , 9.29.1-9.29.15). We have previously reported that human bone marrow (BM)-derived VSELs are able to give rise to vessel formation and endothelial differentiation (Thrombosis and Haemostasis 2015 ; 113 : 1084-1094) and several independent groups confirmed our data with human, mouse, or rat VSELs. Thus, VSELs are a promising source in regenerative medicine for the treatment of vascular diseases. Aim of the study. We aimed to develop an in vitro expansion and differentiation protocol of VSELs into endothelial cells (EC-VSELs) that will provide a clinically relevant cell therapy product without ethical problems and undesirable side effects. Materials and Methods. Highly purified by FACS from umbilical cord blood (UCB), VSELs were sorted as very small lineage-negative, CD45 -, CD34 + cells and then cultured and expanded into EC-VSELs in pro-angiogenic medium supplemented with mesodermal differentiation factors followed by stimulation by endothelial differentiation factors in the presence of UM171 and nicotinamide acid. In parallel, for comparison we expanded ECFCs from MNCs isolated from the same UCB units. The endothelial nature of the expanded VSEL-derived ECs (EC-VSELs) was tested by the expression of typical EC markers as well as by in vitro and in vivo functional angiogenic assays. Results. We report here for the first time a multistep differentiation strategy of highly purified UCB-derived VSELsThese cells after isolation by FACS were small and round, then in the presence of GSK3b inhibitor and BMP4 inducing mesodermal differentiation and high VEGF concentration to induce endothelial differentiation, VSELs enlarged and displayed extended morphology and acquired a characteristic cobblestone morphology. Finally, we have obtained a high number of cells with typical morphology of endothelial cells (EC-VSELs). By inhibiting potential mesodermal transition using TGFb inhibitor, EC-VSELs had a comparable morphology to primary human ECFCs and were characterized by tight junctions, caveolae, and Weibel-Palade Bodies, as demonstrated by transmission electron microscopy analysis of cell cultures conducted on fibrin network on the top of pericardial membranes. ECFCs differentiation was confirmed by analyzing the expression of endothelial markers by flow cytometry, and EC-VSELs were positive for PECAM1, VE-cadherin, VEGFR2, and endoglin. EC-VSELs as compared to ECFCs presented the same levels of expression of all these endothelial markers. What is important at the same time, EC-VSELs, as well as ECFCs, were negative for mesodermal marker Thy-1, confirming their endothelial phenotype. Migration properties of EC-VSELs were studied in basal conditions or in pro-angiogenic conditions using two in vitro models: wound healing assay and Trans well migration assay, and in both models EC-VSELs migration properties were similar to those of ECFCs. Next, we compared paracrine activity by evaluating growth factor and cytokine secretion profile of EC-VSELs, and noticed that the cytokine secretion by expanded VSELs was comparable to that of ECFCs. Moreover, the formation of pseudo-tubes was similar with both conditioned media. Finally, we have assessed the angiogenic capacity of EC-VSELs with a 3D in vitro sprouting assay and in vivo Matrigel plug assay. EC-VSELs display angiogenic properties but with lower potential in comparison with ECFCs which could be explained by their more primitive potential and most likely they need more time to be fully specified into the endothelial lineage. Conclusions. Based on our novel intriguing data, showing that highly purified VSELs expand efficient by employing a two-step differentiation protocol in the presence of UM171 and nicotinamide to EC-VSELs and acquire the same endothelial morphology, phenotype, and secretory potential as ECFCs as well as form functional vessels in in vitro and in vivo angiogenic assays, they could become an alternative source of ECFCs to treat vascular diseases. [Display omitted] DisclosuresNo relevant conflicts of interest to declare.

ELEVATED CIRCULATING ENDOTHELIAL CELLS AND SUCCESS IN ENDOTHELIAL COLONY-FORMING CELLS ISOLATION

Circulating endothelial cells (CEC) have been associated with vascular injury and are described as potential biomarkers for cardiovascular disease (1). Besides, current optimized methodologies enable the isolation of a well-characterized subtype of endothelial progenitor known as Endothelial colony-forming cells (ECFCs) (2,3). Although ECFC isolation methodologies are well described; some discrepancies remain in relation to their isolation efficiency. To evaluate the isolation efficacy ECFCs and CEC frequency in human peripheral blood. The Ethics Research Committee of the University of Campinas approved the experimental procedures and all donors signed the informed consent form. CEC enumeration was assessed by flow cytometry in the peripheral blood of 18 donors. 100 μL of blood (with a leukocyte concentration between 5 and 10 ×10³/μL) was incubated with monoclonal anti-human antibodies (CD45 PerCp, CD133 APC, CD31 FITC, and CD146 PE). FACS lysing solution was used for red blood cell removal. 300,000 events or the total volume of the tube were acquired using a FACSCalibur® flow cytometer (4). To determine the number of cells/μL, the percentage of events was multiplied per number of leucocytes and divided per 100. Cell culture from venous blood was used to isolate ECFCs which were confirmed by their cobblestone morphology and immunophenotyping for endothelial markers (CD31, CD146, CD309, and CD144). ECFC isolation was successful in 9 out of 18 donors (1 male, 8 females; mean age: 35.8 ±11.1 years), and not successful in the other half of donors (2 male, 7 females; mean age: 37.7 ±9.7 years). CEC frequency was significantly higher (p=0.004) in the group with successful ECFC isolation when compared to the group that did not yield ECFCs (2.9 ±1.2 CECs/μL against 1.2 ±0,8 CECs/μL). This suggests that the success in ECFC isolation might be related to the number of CECs, and therefore ECFC mobilization into circulation may also be linked to vascular injury. Increased number of CECs might be associated with the success of ECFCs isolation.