Uncovering the molecular identity of cardiosphere-derived cells (CDCs) by single-cell RNA sequencing.

Cardiosphere-derived cells (CDCs) generated from human cardiac biopsies have been shown to have disease-modifying bioactivity in clinical trials. Paradoxically, CDCs' cellular origin in the heart remains elusive. We studied the molecular identity of CDCs using single-cell RNA sequencing (sc-RNAseq) in comparison to cardiac non-myocyte and non-hematopoietic cells (cardiac fibroblasts/CFs, smooth muscle cells/SMCs and endothelial cells/ECs). We identified CDCs as a distinct and mitochondria-rich cell type that shared biological similarities with non-myocyte cells but not with cardiac progenitor cells derived from human-induced pluripotent stem cells. CXCL6 emerged as a new specific marker for CDCs. By analysis of sc-RNAseq data from human right atrial biopsies in comparison with CDCs we uncovered transcriptomic similarities between CDCs and CFs. By direct comparison of infant and adult CDC sc-RNAseq data, infant CDCs revealed GO-terms associated with cardiac development. To analyze the beneficial effects of CDCs (pro-angiogenic, anti-fibrotic, anti-apoptotic), we performed functional in vitro assays with CDC-derived extracellular vesicles (EVs). CDC EVs augmented in vitro angiogenesis and did not stimulate scarring. They also reduced the expression of pro-apoptotic Bax in NRCMs. In conclusion, CDCs were disclosed as mitochondria-rich cells with unique properties but also with similarities to right atrial CFs. CDCs displayed highly proliferative, secretory and immunomodulatory properties, characteristics that can also be found in activated or inflammatory cell types. By special culture conditions, CDCs earn some bioactivities, including angiogenic potential, which might modify disease in certain disorders.

Differential expression of gut miRNAs in idiopathic Parkinson's disease.

OBJECTIVE: In the present work, we aimed to investigate the expression of microRNAs (miRNAs) in routine colonic biopsies obtained from patients with idiopathic Parkinson's disease (PD) and to address their value as a diagnostic biomarker for PD and their mechanistic contribution to PD onset and progression. METHODS: Patients with PD (n = 13) and healthy controls (n = 17) were prospectively recruited to undergo routine colonic biopsies for cancer screening. Total RNA was extracted from the biopsy material and the expression of miRNAs was quantified by Illumina High-Throughput Sequencing. RESULTS: Statistical analysis revealed a significant submucosal enrichment of the miRNA hsa-miR-486-5p in colonic biopsies from PD patients compared to the control subjects. The expression of miR-486-5p correlated with age and disease severity as measured by the UPDRS and Hoehn & Yahr scale. miRNA gene target analysis identified 301 gene targets that are affected by miR-486-5p. A follow-up associated target identification and pathway enrichment analysis further determined their role in distinct biological processes in the enteric nervous system (ENS). INTERPRETATION: Our work demonstrates an enrichment of submucosal miR-486-5p in routine colonic biopsies from PD patients. Our results will support the examination of miR-486-5p as a PD biomarker and help to understand the significance of the miR-486-5p gene targets for PD onset and progression. In addition, our data will support the investigation of the molecular and cellular mechanisms of GI dysfunction in PD.

Direct modulation of the bone marrow mesenchymal stromal cell compartment by azacitidine enhances healthy hematopoiesis.

Mesenchymal stromal cells (MSCs) are crucial components of the bone marrow (BM) microenvironment essential for regulating self-renewal, survival, and differentiation of hematopoietic stem/progenitor cells (HSPCs) in the stem cell niche. MSCs are functionally altered in myelodysplastic syndromes (MDS) and exhibit an altered methylome compared with MSCs from healthy controls, thus contributing to disease progression. To determine whether MSCs are amenable to epigenetic therapy and if this affects their function, we examined growth, differentiation, and HSPC-supporting capacity of ex vivo-expanded MSCs from MDS patients in comparison with age-matched healthy controls after direct treatment in vitro with the hypomethylating agent azacitidine (AZA). Strikingly, we find that AZA exerts a direct effect on healthy as well as MDS-derived MSCs such that they favor support of healthy over malignant clonal HSPC expansion in coculture experiments. RNA-sequencing analyses of MSCs identified stromal networks regulated by AZA. Notably, these comprise distinct molecular pathways crucial for HSPC support, foremost extracellular matrix molecules (including collagens) and interferon pathway components. Our study demonstrates that the hypomethylating agent AZA exerts its antileukemic activity in part through a direct effect on the HSPC-supporting BM niche and provides proof of concept for the therapeutic potential of epigenetic treatment of diseased MSCs. In addition, our comprehensive data set of AZA-sensitive gene networks represents a valuable framework to guide future development of targeted epigenetic niche therapy in myeloid malignancies such as MDS and acute myeloid leukemia.