Cardiac Mesenchymal Stem Cell-Like Cells Derived from a Young Patient with Bicuspid Aortic Valve Disease Have a Prematurely Aged Phenotype.

There is significant interest in the role of stem cells in cardiac regeneration, and yet little is known about how cardiac disease progression affects native cardiac stem cells in the human heart. In this brief report, cardiac mesenchymal stem cell-like cells (CMSCLC) from the right atria of a 21-year-old female patient with a bicuspid aortic valve and aortic stenosis (referred to as biscuspid aortic valve disease BAVD-CMSCLC), were compared with those of a 78-year-old female patient undergoing coronary artery bypass surgery (referred to as coronary artery disease CAD-CMSCLC). Cells were analyzed for expression of MSC markers, ability to form CFU-Fs, metabolic activity, cell cycle kinetics, expression of NANOG and p16, and telomere length. The cardiac-derived cells expressed MSC markers and were able to form CFU-Fs, with higher rate of formation in CAD-CMSCLCs. BAVD-CMSCLCs did not display normal MSC morphology, had a much lower cell doubling rate, and were less metabolically active than CAD-CMSCLCs. Cell cycle analysis revealed a population of BAVD-CMSCLC in G2/M phase, whereas the bulk of CAD-CMSCLC were in the G0/G1 phase. BAVD-CMSCLC had lower expression of NANOG and shorter telomere lengths, but higher expression of p16 compared with the CAD-CMSCLC. In conclusion, BAVD-CMSCLC have a prematurely aged phenotype compared with CAD-CMSCLC, despite originating from a younger patient

Human cardiac mesenchymal stem cell like cells, a novel cell population with therapeutic potential.

Cardiac stem/progenitors are being used in the clinic to treat patients with a range of cardiac pathologies. However, improvements in heart function following treatment have been reported to be variable, with some showing no response. This discrepancy in response remains unresolved. MSCs have been highlighted as a regenerative tool as these cells display both immunomodulatory and pro-regenerative activity. The purpose of this study was to derive a cardiac MSC population to provide an alternative/support to current therapies. We derived human cardiac-mesenchymal-stem-cell-like-cells (CMSCLC) so named as they share some MSC characteristics. However, CMSCLC lack the MSC tri-lineage differentiation capacity, being capable of only rare adipogenic differentiation and demonstrating low/no osteogenic or chondrogenic potential, a phenotype that may have advantages following transplantation. Further, CMSCLC expressed low levels of p16, high levels of MHCI and low levels of MHCII. A lack of senescent cells would also be advantageous for cells to be used therapeutically, as would the ability to modulate the immune response. Crucially, CMSCLC display a transcriptional profile which includes genes associated with cardio-protective/cardio-beneficial effects. CMSCLC are also secretory and multipotent, giving rise to cardiomyocytes and endothelial cells. Our findings support CMSCLC as a novel cell population suitable for use for transplantation

Cancer Stem Cells and Side Population Cells in Breast Cancer and Metastasis

In breast cancer it is never the primary tumour that is fatal; instead it is the development of metastatic disease which is the major cause of cancer related mortality. There is accumulating evidence that suggests that Cancer Stem Cells (CSC) may play a role in breast cancer development and progression. Breast cancer stem cell populations, including side population cells (SP), have been shown to be primitive stem cell-like populations, being long-lived, self-renewing and highly proliferative. SP cells are identified using dual wavelength flow cytometry combined with Hoechst 33342 dye efflux, this ability is due to expression of one or more members of the ABC transporter family. They have increased resistance to chemotherapeutic agents and apoptotic stimuli and have increased migratory potential above that of the bulk tumour cells making them strong candidates for the metastatic spread of breast cancer. Treatment of nearly all cancers usually involves one first-line agent known to be a substrate of an ABC transporter thereby increasing the risk of developing drug resistant tumours. At present there is no marker available to identify SP cells using immunohistochemistry on breast cancer patient samples. If SP cells do play a role in breast cancer progression/Metastatic Breast Cancer (MBC), combining chemotherapy with ABC inhibitors may be able to destroy both the cells making up the bulk tumour and the cancer stem cell population thus preventing the risk of drug resistant disease, recurrence or metastasis

Characterisation of stem cells in the developing fetal heart

In recent years the adult heart has gone from being thought of as a terminally differentiated organ to one with a limited regenerative capacity. The discovery of several putative cardiac stem/progenitor populations including Is11, c-Kit and side population (SP) cells, has led to the possibility of using cellular therapies to treat cardiac injury. We have previously identified SP cells from the adult mouse and human heart that are able to differentiate along a cardiac lineage. SP cells are characterised by their ability to efflux Hoechst 33342 dye due to the expression of Abcg2 (a member of the ABC transporter family). We have hypothesised that the developing fetal heart would be a stem cells rich environment and that SP cells would be present in the human fetal heart and can be isolated from it.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Nanocarrier-Based Targeted Therapies for Myocardial Infarction

Myocardial infarction is a major cause of morbidity and mortality worldwide. Due to poor inherent regeneration of the adult mammalian myocardium and challenges with effective drug delivery, there has been little progress in regenerative therapies. Nanocarriers, including liposomes, nanoparticles, and exosomes, offer many potential advantages for the therapy of myocardial infarction, including improved delivery, retention, and prolonged activity of therapeutics. However, there are many challenges that have prevented the widespread clinical use of these technologies. This review aims to summarize significant principles and developments in the field, with a focus on nanocarriers using ligand-based or cell mimicry-based targeting. Lastly, a discussion of limitations and potential future direction is provided

Breast Cancer: An Examination of the Potential of ACKR3 to Modify the Response of CXCR4 to CXCL12

Upon binding with the chemokine CXCL12, the chemokine receptor CXCR4 has been shown to promote breast cancer progression. This process, however, can be affected by the expression of the atypical chemokine receptor ACKR3. Given ACKR3’s ability to form heterodimers with CXCR4, we investigated how dual expression of both receptors differed from their lone expression in terms of their signalling pathways. We created single and double CXCR4 and/or ACKR3 Chinese hamster ovary (CHO) cell transfectants. ERK and Akt phosphorylation after CXCL12 stimulation was assessed and correlated with receptor internalization. Functional consequences in cell migration and proliferation were determined through wound healing assays and calcium flux. Initial experiments showed that CXCR4 and ACKR3 were upregulated in primary breast cancer and that CXCR4 and ACKR3 could form heterodimers in transfected CHO cells. This co-expression modified CXCR4’s Akt activation after CXCL12’s stimulation but not ERK phosphorylation (p < 0.05). To assess this signalling disparity, receptor internalization was assessed and it was observed that ACKR3 was recycled to the surface whilst CXCR4 was degraded (p < 0.01), a process that could be partially inhibited with a proteasome inhibitor (p < 0.01). Internalization was also assessed with the ACKR3 agonist VUF11207, which caused both CXCR4 and ACKR3 to be degraded after internalization (p < 0.05 and p < 0.001), highlighting its potential as a dual targeting drug. Interestingly, we observed that CXCR4 but not ACKR3, activated calcium flux after CXCL12 stimulation (p < 0.05) and its co-expression could increase cellular migration (p < 0.01). These findings suggest that both receptors can signal through ERK and Akt pathways but co-expression can alter their kinetics and internalization pathways

The temporal and spatial expression patterns of ABCG2 in the developing human heart

BACKGROUND: The discovery that the adult heart is not a terminally differentiated organ and contains stem/progenitor cells has important implications for the development of cellular therapeutics to treat heart disease. Moreover the discovery of cardiac stem cells might be important in furthering our understanding of both normal and abnormal cardiac development and yet little is known about these cell populations in the developing human heart, which we have focused on in this study. METHODS: The presence of ABCG2 and islet-1 expressing cells in human heart was determined using immunohistochemistry and RT-PCR (and western blotting for ABCG2). Cardiac SP cells were isolated using FACS. Co-localisation immunohistochemistry was used to determine if ABCG2 positive cells expressed other known stem/progenitor cell, endothelial markers or cardiac markers. RESULTS: We observed that ABCG2 expressing cells show a difference in both their temporal and spatial pattern of expression from Islet-1 expressing cardiac progenitors. We identified rare cells that expressed both ABCG2 and markers of other cell lineages including CD31, CD34 and alpha actinin. We also noted the presence of cells that only expressed ABCG2. We isolated cardiac SP cells and confirmed the SP cell phenotype. CONCLUSIONS: Our results suggest that the developing human heart contains at least two distinct cardiac stem/progenitor cell populations one of which, the ABCG2 positive cells, can be readily isolated, suggesting that this tissue could be a useful source of cardiac stem cells