Endothelial derived, secreted long non-coding RNAs Gadlor1 and Gadlor2 aggravate cardiac remodeling.

Pathological cardiac remodeling predisposes individuals to developing heart failure. Here, we investigated two co-regulated long non-coding RNAs (lncRNAs), termed Gadlor1 and Gadlor2, which are upregulated in failing hearts of patients and mice. Cardiac overexpression of Gadlor1 and Gadlor2 aggravated myocardial dysfunction and enhanced hypertrophic and fibrotic remodeling in mice exposed to pressure overload. Compound Gadlor1/2 knockout (KO) mice showed markedly reduced myocardial hypertrophy, fibrosis, and dysfunction, while exhibiting increased angiogenesis during short and prolonged periods of pressure overload. Paradoxically, Gadlor1/2 KO mice suffered from sudden death during prolonged overload, possibly due to cardiac arrhythmia. Gadlor1 and Gadlor2, which are mainly expressed in endothelial cells (ECs) in the heart, where they inhibit pro-angiogenic gene expression, are strongly secreted within extracellular vesicles (EVs). These EVs transfer Gadlor lncRNAs to cardiomyocytes, where they bind and activate calmodulin-dependent kinase II, and impact pro-hypertrophic gene expression and calcium homeostasis. Therefore, we reveal a crucial lncRNA-based mechanism of EC-cardiomyocyte crosstalk during heart failure, which could be specifically modified in the future for therapeutic purposes.

Catecholamine induces endothelial dysfunction via Angiotensin II and intermediate conductance calcium activated potassium channel.

Endothelial dysfunction contributes to the pathogenesis of Takotsubo syndrome (TTS). However, the exact mechanism underlying endothelial dysfunction in the setting of TTS has not been completely clarified. This study aims to investigate the roles of angiotensin II (Ang II) and intermediate-conductance Ca2+-activated K+ (SK4) channels in catecholamine-induced endothelial dysfunction. Human cardiac microvascular endothelial cells (HCMECs) were exposed to 100 µM epinephrine (Epi), mimicking the setting of TTS. Epi treatment increased the ET-1 concentration and reduced NO levels in HCMECs. Importantly, the effects of Epi were found to be mitigated in the presence of Ang II receptor blockers. Furthermore, Ang II mimicked Epi effects on ET-1 and NO production. Additionally, Ang II inhibited tube formation and increased cell apoptosis. The effects of Ang II could be reversed by an SK4 activator NS309 and mimicked by an SK4 channel blocker TRAM-34. Ang II also inhibited the SK4 channel current (ISK4) without affecting its expression level. Ang II could depolarize the cell membrane potential. Ang II promoted ROS release and reduced protein kinase A (PKA) expression. A ROS blocker prevented Ang II effect on ISK4. The PKA activator Sp-8-Br-cAMPS increased SK4 channel currents. Epinephrine enhanced the activity of ACE by activating the α1 receptor/Gq/PKC signal pathway, thereby promoting the secretion of Ang II. The study suggested that high-level catecholamine can increase Ang II release from endothelial cells by α1 receptors/Gq/PKC signal pathway. Ang II can inhibit SK4 channel current by increasing ROS generation and reducing PKA expression, thereby contributing to endothelial dysfunction.

Inter- and Intra-donor variability in bone marrow-derived mesenchymal stromal cells: implications for clinical applications.

BACKGROUND AIMS: Mesenchymal stromal cells (MSCs) are attractive as a therapeutic modality in multiple disease conditions characterized by inflammation and vascular compromise. Logistically they are advantageous because they can be isolated from adult tissue sources, such as bone marrow (BM). The phase 2a START clinical trial determined BM-MSCs to be safe in patients with moderate-to-severe acute respiratory distress syndrome (ARDS). Herein, we examine a subset of the clinical doses of MSCs generated for the phase 2a START trial from three unique donors (1-3), where one of the donors' donated BM on two separate occasions (donor 3 and 3W). METHODS: The main objective of this study was to correlate properties of the cells from the four lots with plasma biomarkers from treated patients and relevant to ARDS outcomes. To do this we evaluated MSC donor lots for (i) post-thaw viability, (ii) growth kinetics, (iii) metabolism, (iv) surface marker expression, (v) protein expression, (vi) immunomodulatory ability and (vii) their functional effects on regulating endothelial cell permeability. RESULTS: MSC-specific marker expression and protection of thrombin-challenged endothelial barrier permeability was similar among all four donor lots. Inter and intra-donor variability was observed in all the other in vitro assays. Furthermore, patient plasma ANG-2 and protein C levels at 6 hours post-transfusion were correlated to cell viability in an inter- and intra-donor dependent manner. CONCLUSIONS: These findings highlight the potential of donor dependent (inter-) and collection dependent (intra-) effects in patient biomarker expression.

Optimization of extracellular vesicles preparation from saliva of head and neck cancer patients.

Small extracellular vesicles from saliva (SEVs) have high potential as biomarkers in Head and Neck cancer (HNC). However, there is no common consensus on the ideal method for their isolation. This study compared different ultracentrifugation (UC) methods (durations and + /- additional purification) with size exclusion chromatography (SEC) and investigated the potential of SEVs as diagnostic biomarkers and their biological activity on NK and CD8+ T cells. SEVs from 19 HNC patients and 8 healthy donors (HDs) were thoroughly characterized. Transmission electron microscopy confirmed the isolation of vesicles by all methods. The average size determined via nanoparticle-tracking analysis was smaller for SEVs isolated by SEC than UC. The highest particle-to-protein yield was achieved by UC (3 h + 3 h) (UCopt) and SEC. However, SEC yielded considerably fewer SEVs. Comparing the surface marker cargo, SEVs isolated by UCopt from HNC patients carried more PD-L1, FasL, and TGF-ß than SEVs from HDs. These levels correlated with tumor stage and HPV status. SEVs downregulated NKG2D expression on primary NK cells. HNC SEVs accelerated CD8+ T cell death compared to HD SEVs. This study suggests that UCopt is preferable when isolation of a high particle-to-protein load is required. Especially PD-L1 and FasL on SEVs hold substantial potential as diagnostic biomarkers.

Adipose Stromal Cell-Derived Secretome Attenuates Cisplatin-Induced Injury In Vitro Surpassing the Intricate Interplay between Proximal Tubular Epithelial Cells and Macrophages.

(1) Background: The chemotherapeutic drug cisplatin exerts toxic side effects causing acute kidney injury. Mesenchymal stromal cells can ameliorate cisplatin-induced kidney injury. We hypothesize that the MSC secretome orchestrates the vicious cycle of injury and inflammation by acting on proximal tubule epithelial cells (PTECs) and macrophages individually, but further by counteracting their cellular crosstalk. (2) Methods: Conditioned medium (CM) from adipose stromal cells was used, first assessing its effect on cisplatin injury in PTECs. Second, the effects of cisplatin and the CM on macrophages were measured. Lastly, in an indirect co-culture system, the interplay between the two cell types was assessed. (3) Results: First, the CM rescued PTECs from cisplatin-induced apoptosis by reducing oxidative stress and expression of nephrotoxicity genes. Second, while cisplatin exerted only minor effects on macrophages, the CM skewed macrophage phenotypes to the anti-inflammatory M2-like phenotype and increased phagocytosis. Finally, in the co-culture system, the CM suppressed PTEC death by inhibiting apoptosis and nuclei fragmentation. The CM lowered TNF-α release, while cisplatin inhibited macrophage phagocytosis, PTECs, and the CM to a greater extent, thus enhancing it. The CM strongly dampened the inflammatory macrophage cytokine secretion triggered by PTECs. (4) Conclusions: ASC-CM surpasses the PTEC-macrophage crosstalk in cisplatin injury. The positive effects on reducing cisplatin cytotoxicity, on polarizing macrophages, and on fine-tuning cytokine secretion underscore MSCs' CM benefit to prevent kidney injury progression.

C-Type Lectin-like Receptor 2 Expression Is Decreased upon Platelet Activation and Is Lower in Most Tumor Entities Compared to Healthy Controls.

The C-type lectin-like receptor 2 (CLEC-2) is expressed on platelets and mediates binding to podoplanin (PDPN) on various cell types. The binding to circulating tumor cells (CTCs) leads to platelet activation and promotes metastatic spread. An increased level of soluble CLEC-2 (sCLEC-2), presumably released from activated platelets, was shown in patients with thromboinflammatory and malignant disease. However, the functional role of sCLEC-2 and the mechanism of sCLEC-2 release are not known. In this study, we focused on the effect of platelet activation on CLEC-2 expression and the sCLEC-2 plasma level in patients with cancer. First, citrated blood from healthy volunteer donors (n = 20) was used to measure the effect of platelet stimulation by classical agonists and PDPN on aggregation, CLEC-2 expression on platelets with flow cytometry, sCLEC-2 release to the plasma with ELISA and total CLEC-2 expression with Western blot analysis. Second, sCLEC-2 was determined in plasma samples from healthy donors (285) and patients with colorectal carcinoma (CRC; 194), melanoma (160), breast cancer (BC; 99) or glioblastoma (49). PDPN caused a significant increase in the aggregation response induced by classical agonists. ADP or PDPN stimulation of platelets caused a significant decrease in CLEC-2 on platelets and sCLEC-2 in the plasma, whereas total CLEC-2 in platelet lysates remained the same. Thus, the increased plasma level of sCLEC-2 is not a suitable biomarker of platelet activation. In patients with CRC (median 0.9 ng/mL), melanoma (0.9 ng/mL) or BC (0.7 ng/mL), we found significantly lower sCLEC-2 levels (p < 0.0001), whereas patients with glioblastoma displayed higher levels (2.6 ng/mL; p = 0.0233) compared to healthy controls (2.1 ng/mL). The low sCLEC-2 plasma level observed in most of the tumor entities of our study presumably results from the internalization of sCLEC-2 by activated platelets or binding of sCLEC-2 to CTCs.

Adipose-Derived Mesenchymal Stem Cells Protect Endothelial Cells from Hypoxic Injury by Suppressing Terminal UPR In Vivo and In Vitro.

Adipose-derived stem cells (ASCs) have been used as a therapeutic intervention for peripheral artery disease (PAD) in clinical trials. To further explore the therapeutic mechanism of these mesenchymal multipotent stromal/stem cells in PAD, this study was designed to test the effect of xenogeneic ASCs extracted from human adipose tissue on hypoxic endothelial cells (ECs) and terminal unfolded protein response (UPR) in vitro and in an atherosclerosis-prone apolipoprotein E-deficient mice (ApoE-/- mice) hindlimb ischemia model in vivo. ASCs were added to Cobalt (II) chloride-treated ECs; then, metabolic activity, cell migration, and tube formation were evaluated. Fluorescence-based sensors were used to assess dynamic changes in Ca2+ levels in the cytosolic- and endoplasmic reticulum (ER) as well as changes in reactive oxygen species. Western blotting was used to observe the UPR pathway. To simulate an acute-on-chronic model of PAD, ApoE-/- mice were subjected to a double ligation of the femoral artery (DLFA). An assessment of functional recovery after DFLA was conducted, as well as histology of gastrocnemius. Hypoxia caused ER stress in ECs, but ASCs reduced it, thereby promoting cell survival. Treatment with ASCs ameliorated the effects of ischemia on muscle tissue in the ApoE-/- mice hindlimb ischemia model. Animals showed less muscle necrosis, less inflammation, and lower levels of muscle enzymes after ASC injection. In vitro and in vivo results revealed that all ER stress sensors (BIP, ATF6, CHOP, and XBP1) were activated. We also observed that the expression of these proteins was reduced in the ASCs treatment group. ASCs effectively alleviated endothelial dysfunction under hypoxic conditions by strengthening ATF6 and initiating a transcriptional program to restore ER homeostasis. In general, our data suggest that ASCs may be a meaningful treatment option for patients with PAD who do not have traditional revascularization options.

Adipose stromal cells bioproducts as cell-free therapies: manufacturing and therapeutic dose determine in vitro functionality.

BACKGROUND: Extracellular vesicles (EV) are considered a cell-free alternative to mesenchymal stromal cell (MSC) therapy. Numerous reports describe the efficacy of EV in conferring immunomodulation and promoting angiogenesis, yet others report these activities to be conveyed in EV-free bioproducts. We hypothesized that this discrepancy may depend either on the method of isolation or rather the relative impact of the individual bioactive components within the MSC secretome. METHODS: To answer this question, we performed an inter-laboratory study evaluating EV generated from adipose stromal cells (ASC) by either sequential ultracentrifugation (UC) or size-exclusion chromatography (SEC). The effect of both EV preparations on immunomodulation and angiogenesis in vitro was compared to that of the whole secretome and of the EV-free protein fraction after SEC isolation. RESULTS: In the current study, neither the EV preparations, the secretome or the protein fraction were efficacious in inhibiting mitogen-driven T cell proliferation. However, EV generated by SEC stimulated macrophage phagocytic activity to a similar extent as the secretome. In turn, tube formation and wound healing were strongly promoted by the ASC secretome and protein fraction, but not by EV. Within the secretome/protein fraction, VEGF was identified as a potential driver of angiogenesis, and was absent in both EV preparations. CONCLUSIONS: Our data indicate that the effects of ASC on immunomodulation and angiogenesis are EV-independent. Specific ASC-EV effects need to be dissected for their use as cell-free therapeutics.

Lymphedema-associated fibroblasts are a TGF-ß1 activated myofibroblast subpopulation related to fibrosis and stage progression in patients and a murine microsurgical model.

BACKGROUND: The driver of secondary lymphedema (SL) progression is chronic inflammation, which promotes fibrosis. Despite advances in preclinical research, a specific effector cell subpopulation as a biomarker for therapy response or stage progression is still missing for SL. METHODS: Whole skin samples of 35 murine subjects of a microsurgical-induced SL model and 12 patients with SL were collected and their fibroblasts were isolated. These lymphedema-derived fibroblasts (LAF) were cultured in a collagen I-poly-D-Lysine 3D hydrogel to mimic skin conditions. Fibroblasts from non-lymphedema skin were used as negative control and TGF-ß-stimulated fibroblasts were used to recreate profibrotic myofibroblasts. Quantitative immunocytofluorescence confocal microscopy analysis and invasion functional assays were performed in all subpopulations and statistically compared. RESULTS: In contrast to normal skin fibroblasts, LAF exhibit α-SMA-positive stress fibers and a reduced number of tight junctions in 3D hydrogel conditions. The switch from normal E-cadherin high phenotype to an N-cadherin high-E-cadherin low morphology suggests epithelial to mesenchymal transition for expansion and proliferation. This pathological behavior of LAF was confirmed by live cell imaging analysis of invasion assays. The significant activation of markers of the TGFBR2-Smad pathway and collagen synthesis (HSP-47) in LAF supports EMT phenotypic changes and previous findings relating to TGF-ß1 and fibrosis with lymphedema. CONCLUSIONS: A characteristic SL myofibroblast subpopulation was identified and translationally related to fibrosis and TGF-ß1-associated stage progression. This SL-related subpopulation was termed lymphedema-associated fibroblasts. A comprehensive stage-related characterization is required to validate LAF as a reliable biomarker for SL disease progression.

Umbilical cord mesenchymal stromal cell-derived extracellular vesicles lack the potency to immunomodulate human monocyte-derived macrophages in vitro.

Mesenchymal stromal cells (MSCs) have been reported to display efficacy in a variety of preclinical models, but without long-term engraftment, suggesting a role for secreted factors, such as MSC-derived extracellular vesicles (EVs). MSCs are known to elicit immunomodulatory effects, an important aspect of which is their ability to affect macrophage phenotype. However, it is not clear if these effects are mediated by MSC-derived EVs, or other factors secreted by the MSCs. Here, we use flow cytometry to assess the effects of human umbilical cord (hUC) MSC-derived EVs on the expression of pro-inflammatory (CD80) and anti-inflammatory (CD163) surface markers in human monocyte-derived macrophages (hMDMs). hUC-MSC-derived EVs did not change the surface marker expression of the hMDMs. In contrast, when hMDMs were co-incubated with hUC-MSCs in indirect co-cultures, changes were observed in the expression of CD14, CD80 and CD163, particularly in M1 macrophages, suggesting that soluble factors are necessary to elicit a shift in phenotype. However, even though EVs did not alter the surface marker expression of macrophages, they promoted angiogenesis and phagocytic capacity increased proportionally to increases in EV concentration. Taken together, these results suggest that hUC-MSC-derived EVs are not sufficient to alter macrophage phenotype and that additional MSC-derived factors are needed.

Flow Cytometric Characterization of Hematopoietic Stem and Progenitor Cell Subpopulations in Autologous Peripheral Blood Stem Cell Preparations after Cryopreservation.

Introduction: Autologous stem cell transplantation is a successful routine procedure with only a small number of non-engraftment cases, although the time to hematopoietic recovery may vary considerably across patients. While CD34 has been the decisive marker for enumerating hematopoietic stem and progenitor cells (HSPCs) for more than 30 years, the impact of CD34-positive cellular subpopulations in autologous HSPC grafts on hematopoietic reconstitution remains unclear. Methods: The two-color ISHAGE protocol represents the current gold standard for CD34+ cell enumeration but includes only the number of viable CD45+/CD34+ cells relative to the body weight of the recipient. We adapted a multicolor flow cytometry marker panel for advanced characterization of CD34 subpopulations in retained samples of autologous peripheral blood stem cell products (n = 49), which had been cryostored for a wide range from 4 to 15 years. The flow cytometric analysis included CD10, CD34, CD38, CD45, CD45RA, CD133, and viability staining with 7AAD. The findings were correlated with clinical engraftment data, including reconstitution of leukocytes, neutrophils, and platelets after transplantation (TPL). Results: We demonstrated that the identification of autologous HSPC subpopulations by flow cytometry after cryopreservation is feasible. Regarding the distribution of HSPC subpopulations, a markedly different pattern was observed in comparison to previously published data obtained using fresh autologous material. Our data revealed the largest ratio of lympho-myeloid progenitors (LMPPs) after freezing and thawing, followed by multipotent progenitors and erythroid-myeloid progenitors. A high ratio of LMPPs, representing an immature stage of differentiation, correlated significantly with early neutrophilic granulocyte and leukocyte engraftment (p = 0.025 and p = 0.003). Conversely, a large ratio of differentiated cells correlated with late engraftment of neutrophilic granulocytes (p = 0.024). Overall, successful engraftment was documented for all patients. Conclusion: We established an advanced flow cytometry panel to assess the differentiation ability of cryostored autologous peripheral blood stem cell grafts and correlated it with timely hematopoietic reconstitution. This approach represents a novel and comprehensive way to identify hematopoietic stem and progenitor subpopulations. It is a feasible way to indicate the engraftment capacity of stem cell products.

Modulation of PD­L1 expression by standard therapy in head and neck cancer cell lines and exosomes.

Although checkpoint inhibitors (CPI) have recently extended the treatment options and improved clinical response of advanced stage head and neck squamous cell carcinoma (HNSCC), treatment success remains unpredictable. Programmed cell death ligand­1 (PD­L1) is a key player in immunotherapy. Tumor cells, and exosomes derived therefrom, are carriers of PD­L1 and efficiently suppress immune responses. The aim of the present study was to analyze the influence of established therapies on PD­L1 expression of HNSCC cell lines and their exosomes. The HNSCC cell lines, UM­SCC­11B, UM­SCC­14C and UM­SCC­22C were treated with fractionated radiotherapy (RT; 5x2 Gy), cisplatin (CT) and cetuximab (Cetux) as monotherapy, or combined therapy, chemoradiotherapy (CRT; RT and CT) or radioimmunotherapy (RT and Cetux). The expression of PD­L1 and phosphorylated (p)ERK1/2 as a mediator of radioresistance were assessed using western blotting, immunohistochemistry and an ex vivo vital tissue culture model. Additionally, exosomes were isolated from concentrated supernatants of the (un­)treated HNSCC cell lines by size exclusion chromatography. Exosomal protein expression levels of PD­L1 were detected using western blotting and semi­quantitative levels were calculated. The functional impact of exosomes from the (un­)treated HNSCC cell lines on the proliferation (MTS assay) and apoptosis (Caspase 3/7 assay) of the untreated HNSCC cell lines were measured and compared. The HNSCC cell lines UM­SCC­11B and UM­SCC­22B showed strong expression of pERK1/2 and PD­L1, respectively. RT upregulated the PD­L1 expression in UM­SCC­11B and UM­SCC­14C and in exosomes from all three cell lines. CT alone induced PD­L1 expression in all cell lines. CRT induced the expression of PD­L1 in all HNSCC cell lines and exosomes from UM­SCC­14C and UM­SCC­22B. The data indicated a potential co­regulation of PD­L1 and activated ERK1/2, most evident in UM­SCC­14C. Exosomes from irradiated UM­SCC­14C cells protected the unirradiated cells from apoptosis by Caspase 3/7 downregulation. The present study suggested a tumor cell­mediated regulation of PD­L1 upon platinum­based CRT in HNSCC and in exosomes. A co­regulation of PD­L1 and MAPK signaling response was hypothesized.

Harmonised culture procedures minimise but do not eliminate mesenchymal stromal cell donor and tissue variability in a decentralised multicentre manufacturing approach.

BACKGROUND: Mesenchymal stromal cells (MSCs), commonly sourced from adipose tissue, bone marrow and umbilical cord, have been widely used in many medical conditions due to their therapeutic potential. Yet, the still limited understanding of the underlying mechanisms of action hampers clinical translation. Clinical potency can vary considerably depending on tissue source, donor attributes, but importantly, also culture conditions. Lack of standard procedures hinders inter-study comparability and delays the progression of the field. The aim of this study was A- to assess the impact on MSC characteristics when different laboratories, performed analysis on the same MSC material using harmonised culture conditions and B- to understand source-specific differences. METHODS: Three independent institutions performed a head-to-head comparison of human-derived adipose (A-), bone marrow (BM-), and umbilical cord (UC-) MSCs using harmonised culture conditions. In each centre, cells from one specific tissue source were isolated and later distributed across the network to assess their biological properties, including cell expansion, immune phenotype, and tri-lineage differentiation (part A). To assess tissue-specific function, angiogenic and immunomodulatory properties and the in vivo biodistribution were compared in one expert lab (part B). RESULTS: By implementing a harmonised manufacturing workflow, we obtained largely reproducible results across three independent laboratories in part A of our study. Unique growth patterns and differentiation potential were observed for each tissue source, with similar trends observed between centres. Immune phenotyping verified expression of typical MSC surface markers and absence of contaminating surface markers. Depending on the established protocols in the different laboratories, quantitative data varied slightly. Functional experiments in part B concluded that conditioned media from BM-MSCs significantly enhanced tubulogenesis and endothelial migration in vitro. In contrast, immunomodulatory studies reported superior immunosuppressive abilities for A-MSCs. Biodistribution studies in healthy mice showed lung entrapment after administration of all three types of MSCs, with a significantly faster clearance of BM-MSCs. CONCLUSION: These results show the heterogeneous behaviour and regenerative properties of MSCs as a reflection of intrinsic tissue-origin properties while providing evidence that the use of harmonised culture procedures can reduce but do not eliminate inter-lab and operator differences.

Clinical-grade human skin-derived ABCB5+ mesenchymal stromal cells exert anti-apoptotic and anti-inflammatory effects in vitro and modulate mRNA expression in a cisplatin-induced kidney injury murine model.

Acute kidney injury (AKI) is characterized by a rapid reduction in renal function and glomerular filtration rate (GFR). The broadly used anti-cancer chemotherapeutic agent cisplatin often induces AKI as an adverse drug side effect. Therapies targeted at the reversal of AKI and its potential progression to chronic kidney disease or end-stage renal disease are currently insufficiently effective. Mesenchymal stromal cells (MSCs) possess diverse immunomodulatory properties that confer upon them significant therapeutic potential for the treatment of diverse inflammatory disorders. Human dermal MSCs expressing ATP-Binding Cassette member B5 (ABCB5) have shown therapeutic efficacy in clinical trials in chronic skin wounds or recessive dystrophic epidermolysis bullosa. In preclinical studies, ABCB5+ MSCs have also shown to reverse metabolic reprogramming in polycystic kidney cells, suggesting a capacity for this cell subset to improve also organ function in kidney diseases. Here, we aimed to explore the therapeutic capacity of ABCB5+ MSCs to improve renal function in a preclinical rat model of cisplatin-induced AKI. First, the anti-apoptotic and immunomodulatory capacity was compared against research-grade adipose stromal cells (ASCs). Then, cross-species immunomodulatory capacity was checked, testing first inhibition of mitogen-driven peripheral blood mononuclear cells and then modulation of macrophage function. Finally, therapeutic efficacy was evaluated in a cisplatin AKI model. First, ABCB5+ MSCs suppressed cisplatin-induced apoptosis of human conditionally-immortalized proximal tubular epithelial cells in vitro, most likely by reducing oxidative stress. Second, ABCB5+ MSCs inhibited the proliferation of either human or rat peripheral blood mononuclear cells, in the human system via the Indoleamine/kynurenine axis and in the murine context via nitric oxide/nitrite. Third, ABCB5+ MSCs decreased TNF-α secretion after lipopolysaccharide stimulation and modulated phagocytosis and in both human and rat macrophages, involving prostaglandin E2 and TGF-ß1, respectively. Fourth, clinical-grade ABCB5+ MSCs grafted intravenously and intraperitoneally to a cisplatin-induced AKI murine model exerted modulatory effects on mRNA expression patterns toward an anti-inflammatory and pro-regenerative state despite an apparent lack of amelioration of renal damage at physiologic, metabolic, and histologic levels. Our results demonstrate anti-inflammatory and pro-regenerative effects of clinical grade ABCB5+ MSCs in vitro and in vivo and suggest potential therapeutic utility of this cell population for treatment or prevention of cisplatin chemotherapy-induced tissue toxicity.

Pooled human bone marrow-derived mesenchymal stromal cells with defined trophic factors cargo promote dermal wound healing in diabetic rats by improved vascularization and dynamic recruitment of M2-like macrophages.

Human Mesenchymal Stromal Cells (hMSCs) are a promising source for cell-based therapies. Yet, transition to phase III and IV clinical trials is remarkably slow. To mitigate donor variabilities and to obtain robust and valid clinical data, we aimed first to develop a manufacturing concept balancing large-scale production of pooled hMSCs in a minimal expansion period, and second to test them for key manufacture and efficacy indicators in the clinically highly relevant indication wound healing. Our novel clinical-scale manufacturing concept is comprised of six single donor hMSCs master cell banks that are pooled to a working cell bank from which an extrapolated number of 70,000 clinical doses of 1x106 hMSCs/cm2 wound size can be manufactured within only three passages. The pooled hMSC batches showed high stability of key manufacture indicators such as morphology, immune phenotype, proliferation, scratch wound healing, chemotactic migration and angiogenic support. Repeated topical hMSCs administration significantly accelerated the wound healing in a diabetic rat model by delivering a defined growth factor cargo (specifically BDNF, EGF, G-CSF, HGF, IL-1α, IL-6, LIF, osteopontin, VEGF-A, FGF-2, TGF-ß, PGE-2 and IDO after priming) at the specific stages of wound repair, namely inflammation, proliferation and remodeling. Specifically, the hMSCs mediated epidermal and dermal maturation and collagen formation, improved vascularization, and promoted cell infiltration. Kinetic analyses revealed transient presence of hMSCs until day (d)4, and the dynamic recruitment of macrophages infiltrating from the wound edges (d3) and basis (d9), eventually progressing to the apical wound on d11. In the wounds, the hMSCs mediated M2-like macrophage polarization starting at d4, peaking at d9 and then decreasing to d11. Our study establishes a standardized, scalable and pooled hMSC therapeutic, delivering a defined cargo of trophic factors, which is efficacious in diabetic wound healing by improving vascularization and dynamic recruitment of M2-like macrophages. This decision-making study now enables the validation of pooled hMSCs as treatment for impaired wound healing in large randomized clinical trials.

Case Studies Exemplifying the Transition to Animal Component-free Cell Culture.

Cell culture techniques are strongly connected with modern scientific laboratories and production facilities. Thus, choosing the most suitable medium for the cells involved is vital, not only directly to optimise cell viability but also indirectly to maximise the reliability of the experiments performed with the cells. Fetal bovine or calf serum (FBS or FCS, respectively) is the most commonly used cell culture medium supplement, providing various nutritional factors and macromolecules essential for cell growth. Yet, the use of FBS encompasses a number of disadvantages. Scientifically, one of the most severe disadvantages is the lot-to-lot variability of animal sera that hampers reproducibility. Therefore, transitioning from the use of these ill-defined, component-variable, inconsistent, xenogenic, ethically questionable and even potentially infectious media supplements, is key to achieving better data reproducibility and thus better science. To demonstrate that the transition to animal component-free cell culture is possible and achievable, we highlight three different scenarios and provide some case studies of each, namely: i) the adaptation of single cell lines to animal component-free culture conditions by the replacement of FBS and trypsin; ii) the adaptation of multicellular models to FBS-free conditions; and (iii) the replacement of FBS with human platelet lysate (hPL) for the generation of primary stem/stromal cell cultures for clinical purposes. By highlighting these examples, we aim to foster and support the global movement towards more consistent science and provide evidence that it is indeed possible to step out of the currently smouldering scientific reproducibility crisis.

Functional Characterization of Human Induced Pluripotent Stem Cell-Derived Endothelial Cells.

Endothelial cells derived from human induced pluripotent stem cells (hiPSC-ECs) provide a new opportunity for mechanistic research on vascular regeneration and drug screening. However, functions of hiPSC-ECs still need to be characterized. The objective of this study was to investigate electrophysiological and functional properties of hiPSC-ECs compared with primary human cardiac microvascular endothelial cells (HCMECs), mainly focusing on ion channels and membrane receptor signaling, as well as specific cell functions. HiPSC-ECs were derived from hiPS cells that were generated from human skin fibroblasts of three independent healthy donors. Phenotypic and functional comparison to HCMECs was performed by flow cytometry, immunofluorescence staining, quantitative reverse-transcription polymerase chain reaction (qPCR), enzyme-linked immunosorbent assay (ELISA), tube formation, LDL uptake, exosome release assays and, importantly, patch clamp techniques. HiPSC-ECs were successfully generated from hiPS cells and were identified by endothelial markers. The mRNA levels of KCNN2, KCNN4, KCNMA1, TRPV2, and SLC8A1 in hiPSC-ECs were significantly higher than HCMECs. AT1 receptor mRNA level in hiPSC-ECs was higher than in HCMECs. AT2 receptor mRNA level was the highest among all receptors. Adrenoceptor ADRA2 expression in hiPSC-ECs was lower than in HCMECs, while ADRA1, ADRB1, ADRB2, and G-protein GNA11 and Gai expression were similar in both cell types. The expression level of muscarinic and dopamine receptors CHRM3, DRD2, DRD3, and DRD4 in hiPSC-ECs were significantly lower than in HCMECs. The functional characteristics of endothelial cells, such as tube formation and LDL uptake assay, were not statistically different between hiPSC-ECs and HCMECs. Phenylephrine similarly increased the release of the vasoconstrictor endothelin-1 (ET-1) in hiPSC-ECs and HCMECs. Acetylcholine also similarly increased nitric oxide generation in hiPSC-ECs and HCMECs. The resting potentials (RPs), ISK1-3, ISK4 and IK1 were similar in hiPSC-ECs and HCMECs. IBK was larger and IKATP was smaller in hiPSC-ECs. In addition, we also noted a higher expression level of exosomes marker CD81 in hiPSC-ECs and a higher expression of CD9 and CD63 in HCMECs. However, the numbers of exosomes extracted from both types of cells did not differ significantly. The study demonstrates that hiPSC-ECs are similar to native endothelial cells in ion channel function and membrane receptor-coupled signaling and physiological cell functions, although some differences exist. This information may be helpful for research using hiPSC-ECs.

Noninferior Red Cell Concentrate Quality after Repeated Air Rescue Mission Transport for Prehospital Transfusion.

Background: Transfusion of red cell concentrates (RCCs) is an integral therapy after severe hemorrhage or trauma. Prehospital transfusion offers an immediate intervention in emergency cases. Air ambulance-based prehospital transfusion, already used in different countries, is currently established in Germany. Limited information is available for regulatory-compliant transport logistics of RCCs and their quality after repeated air rescue missions. Thus, the aim of this study was (i) to validate regulatory-compliant logistics and (ii) to assess product quality, analyzing biochemical parameters and RBC morphology. Study Design and Methods: Due to regulatory requirements, we adapted a rotation system of 1 day transport, 1 day quarantine storage and 1 day storage over the entire RCC shelf life. RCCs transported on air rescue missions (flight group) were compared against a control group, treated identically except for helicopter transport. RCCs were visually inspected, and their temperature was documented throughout the entire rotation cycles. RCCs at the end of shelf life (end point samples) were assessed for levels of hemoglobin, hematocrit, free hemoglobin, hemolysis, mean corpuscular volume, potassium and pH. In addition, morphological changes were assessed using flow morphometry. Results: In total 81 RCCs were assessed in the flight group and 50 in the control group. Within the flight group, 30 RCCs were transfused. RCCs were dispatched on average 11 times (7-13 times). The average flight time was 18.3 h (6.6-28.8 h). The rotation system ensured adherence to regulatory guidelines, especially compliance to storage conditions of +2 to +6°C of intermediate storage. Biochemical and morphological quality parameters did not exhibit any changes upon repeated air rescue missions. A correlation with respect to the flight time was not observed either. Discussion: The quality of RCCs after repeated air rescue missions is noninferior to control samples regarding biochemical and morphological parameters. The product quality is within German regulations for up to 42 days of storage. The logistics and maintenance of the thermal conditions are safe and feasible. Thus, a rotation system of RCCs offers a regulatory-compliant option to supply air rescue missions with RCCs to allow life-saving prehospital transfusions at the incident scene.

Biomarkers and 3D models predicting response to immune checkpoint blockade in head and neck cancer (Review).

Immunotherapy has evolved into a powerful tool in the fight against a number of types of cancer, including head and neck squamous cell carcinomas (HNSCC). Although checkpoint inhibition (CPI) has definitely enriched the treatment options for advanced stage HNSCC during the past decade, the percentage of patients responding to treatment is widely varying between 14­32% in second­line setting in recurrent or metastatic HNSCC with a sporadic durability. Clinical response and, consecutively, treatment success remain unpredictable in most of the cases. One potential factor is the expression of target molecules of the tumor allowing cancer cells to acquire therapy resistance mechanisms. Accordingly, analyzing and modeling the complexity of the tumor microenvironment (TME) is key to i) stratify subgroups of patients most likely to respond to CPI and ii) to define new combinatorial treatment regimens. Particularly in a heterogeneous disease such as HNSCC, thoroughly studying the interactions and crosstalking between tumor and TME cells is one of the biggest challenges. Sophisticated 3D models are therefore urgently needed to be able to validate such basic science hypotheses and to test novel immuno­oncologic treatment regimens in consideration of the individual biology of each tumor. The present review will first summarize recent findings on immunotherapy, predictive biomarkers, the role of the TME and signaling cascades eliciting during CPI. Second, it will highlight the significance of current promising approaches to establish HNSCC 3D models for new immunotherapies. The results are encouraging and indicate that data obtained from patient­specific tumors in a dish might be finally translated into personalized immuno­oncology.

Potential Therapeutic Effects of Long-Term Stem Cell Administration: Impact on the Gene Profile and Kidney Function of PKD/Mhm (Cy/+) Rats.

Cystic kidney disease (CKD) is a heterogeneous group of genetic disorders and one of the most common causes of end-stage renal disease. Here, we investigate the potential effects of long-term human stem cell treatment on kidney function and the gene expression profile of PKD/Mhm (Cy/+) rats. Human adipose-derived stromal cells (ASC) and human skin-derived ABCB5+ stromal cells (2 × 106) were infused intravenously or intraperitoneally monthly, over 6 months. Additionally, ASC and ABCB5+-derived conditioned media were administrated intraperitoneally. The gene expression profile results showed a significant reprogramming of metabolism-related pathways along with downregulation of the cAMP, NF-kB and apoptosis pathways. During the experimental period, we measured the principal renal parameters as well as renal function using an innovative non-invasive transcutaneous device. All together, these analyses show a moderate amelioration of renal function in the ABCB5+ and ASC-treated groups. Additionally, ABCB5+ and ASC-derived conditioned media treatments lead to milder but still promising improvements. Even though further analyses have to be performed, the preliminary results obtained in this study can lay the foundations for a novel therapeutic approach with the application of cell-based therapy in CKD.