RhoA GTPase switch controls Cx43-hemichannel activity through the contractile system

ATP-dependent paracrine signaling, mediated via the release of ATP through plasma membrane-embedded hemichannels of the connexin family, coordinates a synchronized response between neighboring cells. Connexin 43 (Cx43) hemichannels that are present in the plasma membrane need to be tightly regulated to ensure cell viability. In monolayers of bovine corneal endothelial cells (BCEC),Cx43-mediated ATP release is strongly inhibited when the cells are treated with inflammatory mediators, in particular thrombin and histamine. In this study we investigated the involvement of RhoA activation in the inhibition of hemichannel-mediated ATP release in BCEC. We found that RhoA activation occurs rapidly and transiently upon thrombin treatment of BCEC. The RhoA activity correlated with the onset of actomyosin contractility that is involved in the inhibition of Cx43 hemichannels. RhoA activation and inhibition of Cx43-hemichannel activity were both prevented by pre-treatment of the cells with C3-toxin as well as knock down of RhoA by siRNA. These findings provide evidence that RhoA activation is a key player in thrombin-induced inhibition of Cx43-hemichannel activity. This study demonstrates that RhoA GTPase activity is involved in the acute inhibition of ATP-dependent paracrine signaling, mediated by Cx43 hemichannels, in response to the inflammatory mediator thrombin. Therefore, RhoA appears to be an important molecular switch that controls Cx43 hemichannel openings and hemichannel-mediated ATP-dependent paracrine intercellular communication under (patho) physiological conditions of stress

Messenger RNA electroporation: an efficient tool in immunotherapy and stem cell research.

Over the last decades medicine has developed tremendously, but still many diseases are incurable. The last years, cellular (gene) therapy has become a hot topic in biomedical research for the potential treatment of cancer, AIDS and diseases involving cell loss or degeneration. Here, we will focus on two major areas within cellular therapy, cellular immunotherapy and stem cell therapy, that could benefit from the introduction of neo-expressed genes through mRNA electroporation for basic research as well as for clinical applications. For cellular immunotherapy, we will provide a state-of-the-art on loading antigen-presenting cells with antigens in the mRNA format for manipulation of T cell immunity. In the area of stem cell research, we will highlight current gene transfer methods into adult and embryonic stem cells and discuss the use of mRNA electroporation for controlling guided differentiation of stem cells into specialized cell lineages

Insights and future directions for the application of perinatal derivatives in eye diseases: A critical review of preclinical and clinical studies.

Perinatal derivatives (PnD) are gaining interest as a source for cell-based therapies. Since the eye is easily accessible to local administration, eye diseases may be excellent candidates to evaluate novel therapeutic approaches. With this work, we performed a systematic review of published preclinical and clinical studies addressing PnD in the treatment of ocular diseases. We have set two specific objectives: (i) to investigate the current level of standardization in applied technical procedures in preclinical studies and (ii) to assess clinical efficacy in clinical trials. Hereto, we selected studies that applied amniotic membrane (hAM) and mesenchymal stromal cells derived from amniotic membrane (hAMSC), placenta (hPMSC), umbilical cord (hUC-MSC) and Wharton's Jelly (hUC-WJ-MSC), excluding those where cells were not transplanted individually, following a systematic PubMed search for preclinical studies and consultation of clinical studies on https://clinicaltrials.gov and https://www.clinicaltrialsregister.eu/. Our bibliographic search retrieved 26 pre-clinical studies and 27 clinical trials. There was a considerable overlap regarding targeted ocular structures. Another common feature is the marked tendency towards (i) locally administered treatments and (ii) the PnD type. In the cornea/ocular surface, hAM was preferred and usually applied directly covering the ocular surface. For neuroretinal disorders, intra-ocular injection of umbilical or placental-derived cells was preferred. In general, basic research reported favourable outcomes. However, due to lack of standardization between different studies, until now there is no clear consensus regarding the fate of administered PnD or their mode of action. This might be accountable for the low index of clinical translation. Regarding clinical trials, only a minority provided results and a considerable proportion is in "unknown status". Nevertheless, from the limited clinical evidence available, hAM proved beneficial in the symptomatic relief of bullous keratopathy, treating dry eye disease and preventing glaucoma drainage device tube exposure. Regarding neuroretinal diseases, application of Wharton's Jelly MSC seems to become a promising future approach. In conclusion, PnD-based therapies seem to be beneficial in the treatment of several ocular diseases. However, much is yet to be done both in the pre-clinical and in the clinical setting before they can be included in the daily ophthalmic practice

The ratio of SRPK1/SRPK1a regulates erythroid differentiation in K562 leukaemic cells

AbstractSRPK1, the prototype of the serine/arginine family of kinases, has been implicated in the regulation of multiple cellular processes such as pre-mRNA splicing, chromatin structure, nuclear import and germ cell development. SRPK1a is a much less studied isoform of SRPK1 that contains an extended N-terminal domain and so far has only been detected in human testis. In the present study we show that SRPK1 is the predominant isoform in K562 cells, with the ratio of the two isoforms being critical in determining cell fate. Stable overexpression of SRPK1a induces erythroid differentiation of K562 cells. The induction of globin synthesis was accompanied by a marked decrease in proliferation and a significantly reduced clonogenic potential. Small interfering RNA-mediated down-regulation of SRPK1 in K562 cells results similarly in a decrease in proliferative capacity and induction of globin synthesis. A decreased SRPK1/SRPK1a ratio is also observed upon hemin/DMSO-induced differentiation of K562 cells as well as in normal human erythroid progenitor cells. Mass spectrometric analysis of SRPK1a-associated proteins identified multiple classes of RNA-binding proteins including RNA helicases, heterogeneous nuclear ribonucleoproteins, ribosomal proteins, and mRNA-associated proteins. Several of the SRPK1a-copurifying proteins have been previously identified in ribosomal and pre-ribosomal complexes, thereby suggesting that SRPK1a may play an important role in linking ribosomal assembly and/or function to erythroid differentiation in human leukaemic cells

Heparin-based, injectable microcarriers for controlled delivery of interleukin-13 to the brain

Interleukin-13 (IL-13) drives cells of myeloid origin towards a more anti-inflammatory phenotype, but delivery to the brain remains problematic. Herein, we show that heparin-based cryogel microcarriers load high amounts of IL-13, releasing it slowly. Intra-striatal injection of loaded microcarriers caused local up-regulation of ARG1 in myeloid cells for pro-regenerative immunomodulation in the brain. © 2020 The Royal Society of Chemistry

Application of Perinatal Derivatives on Oncological Preclinical Models: A Review of Animal Studies.

The increasing cancer incidence has certified oncological management as one of the most critical challenges for the coming decades. New anticancer strategies are still needed, despite the significant advances brought to the forefront in the last decades. The most recent, promising therapeutic approaches have benefitted from the application of human perinatal derivatives (PnD), biological mediators with proven benefits in several fields beyond oncology. To elucidate preclinical results and clinic outcomes achieved in the oncological field, we present a narrative review of the studies resorting to animal models to assess specific outcomes of PnD products. Recent preclinical evidence points to promising anticancer effects offered by PnD mediators isolated from the placenta, amniotic membrane, amniotic fluid, and umbilical cord. Described effects include tumorigenesis prevention, uncontrolled growth or regrowth inhibition, tumor homing ability, and adequate cell-based delivery capacity. Furthermore, PnD treatments have been described as supportive of chemotherapy and radiological therapies, particularly when resistance has been reported. However, opposite effects of PnD products have also been observed, offering support and trophic effect to malignant cells. Such paradoxical and dichotomous roles need to be intensively investigated. Current hypotheses identify as explanatory some critical factors, such as the type of the PnD biological products used or the manufacturing procedure to prepare the tissue/cellular treatment, the experimental design (including human-relevant animal models), and intrinsic pathophysiological characteristics. The effective and safe translation of PnD treatments to clinical practice relies on the collaborative efforts of all researchers working with human-relevant oncological preclinical models. However, it requires proper guidelines and consensus compiled by experts and health workers who accurately describe the methodology of tissue collection, PnD isolation, manufacturing, preservation, and delivery to the final user

Heparin-based, injectable microcarriers for controlled delivery of interleukin-13 to the brain

Interleukin-13 (IL-13) drives cells of myeloid origin towards a more anti-inflammatory phenotype, but delivery to the brain remains problematic. Herein, we show that heparin-based cryogel microcarriers load high amounts of IL-13, releasing it slowly. Intra-striatal injection of loaded microcarriers caused local up-regulation of ARG1 in myeloid cells for pro-regenerative immunomodulation in the brain

Plasmid-based genetic modification of human bone marrow-derived stromal cells: analysis of cell survival and transgene expression after transplantation in rat spinal cord

<p>Abstract</p> <p>Background</p> <p>Bone marrow-derived stromal cells (MSC) are attractive targets for <it>ex vivo </it>cell and gene therapy. In this context, we investigated the feasibility of a plasmid-based strategy for genetic modification of human (h)MSC with enhanced green fluorescent protein (EGFP) and neurotrophin (NT)3. Three genetically modified hMSC lines (EGFP, NT3, NT3-EGFP) were established and used to study cell survival and transgene expression following transplantation in rat spinal cord.</p> <p>Results</p> <p>First, we demonstrate long-term survival of transplanted hMSC-EGFP cells in rat spinal cord under, but not without, appropriate immune suppression. Next, we examined the stability of EGFP or NT3 transgene expression following transplantation of hMSC-EGFP, hMSC-NT3 and hMSC-NT3-EGFP in rat spinal cord. While <it>in vivo </it>EGFP mRNA and protein expression by transplanted hMSC-EGFP cells was readily detectable at different time points post-transplantation, <it>in vivo </it>NT3 mRNA expression by hMSC-NT3 cells and <it>in vivo </it>EGFP protein expression by hMSC-NT3-EGFP cells was, respectively, undetectable or declined rapidly between day 1 and 7 post-transplantation. Further investigation revealed that the observed <it>in vivo </it>decline of EGFP protein expression by hMSC-NT3-EGFP cells: (i) was associated with a decrease in transgenic NT3-EGFP mRNA expression as suggested following laser capture micro-dissection analysis of hMSC-NT3-EGFP cell transplants at day 1 and day 7 post-transplantation, (ii) did not occur when hMSC-NT3-EGFP cells were transplanted subcutaneously, and (iii) was reversed upon re-establishment of hMSC-NT3-EGFP cell cultures at 2 weeks post-transplantation. Finally, because we observed a slowly progressing tumour growth following transplantation of all our hMSC cell transplants, we here demonstrate that omitting immune suppressive therapy is sufficient to prevent further tumour growth and to eradicate malignant xenogeneic cell transplants.</p> <p>Conclusion</p> <p>In this study, we demonstrate that genetically modified hMSC lines can survive in healthy rat spinal cord over at least 3 weeks by using adequate immune suppression and can serve as vehicles for transgene expression. However, before genetically modified hMSC can potentially be used in a clinical setting to treat spinal cord injuries, more research on standardisation of hMSC culture and genetic modification needs to be done in order to prevent tumour formation and transgene silencing <it>in vivo</it>.</p

PapRIV, a BV-2 microglial cell activating quorum sensing peptide

Quorum sensing peptides (QSPs) are bacterial peptides produced by Gram-positive bacteria to communicate with their peers in a cell-density dependent manner. These peptides do not only act as interbacterial communication signals, but can also have effects on the host. Compelling evidence demonstrates the presence of a gut-brain axis and more specifically, the role of the gut microbiota in microglial functioning. The aim of this study is to investigate microglial activating properties of a selected QSP (PapRIV) which is produced by Bacillus cereus species. PapRIV showed in vitro activating properties of BV-2 microglia cells and was able to cross the in vitro Caco-2 cell model and reach the brain. In vivo peptide presence was also demonstrated in mouse plasma. The peptide caused induction of IL-6, TNFα and ROS expression and increased the fraction of ameboid BV-2 microglia cells in an NF-κB dependent manner. Different metabolites were identified in serum, of which the main metabolite still remained active. PapRIV is thus able to cross the gastro-intestinal tract and the blood–brain barrier and shows in vitro activating properties in BV-2 microglia cells, hereby indicating a potential role of this quorum sensing peptide in gut-brain interaction

Guidelines to Analyze Preclinical Studies Using Perinatal Derivatives.

The last 18 years have brought an increasing interest in the therapeutic use of perinatal derivatives (PnD). Preclinical studies used to assess the potential of PnD therapy include a broad range of study designs. The COST SPRINT Action (CA17116) aims to provide systematic and comprehensive reviews of preclinical studies for the understanding of the therapeutic potential and mechanisms of PnD in diseases and injuries that benefit from PnD therapy. Here we describe the publication search and data mining, extraction, and synthesis strategies employed to collect and prepare the published data selected for meta-analyses and reviews of the efficacy of PnD therapies for different diseases and injuries. A coordinated effort was made to prepare the data suitable to make statements for the treatment efficacy of the different types of PnD, routes, time points, and frequencies of administration, and the dosage based on clinically relevant effects resulting in clear increase, recovery or amelioration of the specific tissue or organ function. According to recently proposed guidelines, the harmonization of the nomenclature of PnD types will allow for the assessment of the most efficient treatments in various disease models. Experts within the COST SPRINT Action (CA17116), together with external collaborators, are doing the meta-analyses and reviews using the data prepared with the strategies presented here in the relevant disease or research fields. Our final aim is to provide standards to assess the safety and clinical benefit of PnD and to minimize redundancy in the use of animal models following the 3R principles for animal experimentation