Obligate intracellular Chlamydia trachomatis replicate in a membrane-bound vacuole called inclusion, which serves as a signaling interface with the host cell. Here, we show that the chlamydial deubiquitinating enzyme (Cdu) 1 localizes in the inclusion membrane and faces the cytosol with the active deubiquitinating enzyme domain. The structure of this domain revealed high similarity to mammalian deubiquitinases with a unique α-helix close to the substrate-binding pocket. We identified the apoptosis regulator Mcl-1 as a target that interacts with Cdu1 and is stabilized by deubiquitination at the chlamydial inclusion. A chlamydial transposon insertion mutant in the Cdu1-encoding gene exhibited increased Mcl-1 and inclusion ubiquitination and reduced Mcl-1 stabilization. Additionally, inactivation of Cdu1 led to increased sensitivity of C. trachomatis for IFNγ and impaired infection in mice. Thus, the chlamydial inclusion serves as an enriched site for a deubiquitinating activity exerting a function in selective stabilization of host proteins and protection from host defense.DOI: http://dx.doi.org/10.7554/eLife.21465.001

The Effect of extracellular vesicles derived from human stromal cells on the inner ear has been investigated. The vesicles were characterized and tested in vitro in spiral ganglion neurons and in vivo in a mouse noise trauma model.

Interest in mesenchymal stem cell derived extracellular vesicles (MSC‐EVs) as therapeutic agents has dramatically increased over the last decade. Current approaches to the characterization and quality control of EV‐based therapeutics include particle tracking techniques, Western blotting, and advanced cytometry, but standardized methods are lacking. In this study, we established and verified quartz crystal microbalance (QCM) as highly sensitive label‐free immunosensing technique for characterizing clinically approved umbilical cord MSC‐EVs enriched by tangential flow filtration and ultracentrifugation. Using QCM in conjunction with common characterization methods, we were able to specifically detect EVs via EV (CD9, CD63, CD81) and MSC (CD44, CD49e, CD73) markers. Furthermore, analysis of QCM dissipation versus frequency allowed us to quantitatively determine the ratio of marker‐specific EVs versus non‐vesicular particles (NVPs) – a parameter that cannot be obtained by any other technique so far. Additionally, we characterized the topography and elasticity of these EVs by atomic force microscopy (AFM), enabling us to distinguish between EVs and NVPs in our EV preparations. This measurement modality makes it possible to identify EV sub‐fractions, discriminate between EVs and NVPs, and to characterize EV surface proteins, all with minimal sample preparation and using label‐free measurement devices with low barriers of entry for labs looking to widen their spectrum of characterization techniques. Our combination of QCM with impedance measurement (QCM‐I) and AFM measurements provides a robust multi‐marker approach to the characterization of clinically approved EV therapeutics and opens the door to improved quality control.

Extracellular vesicles (EVs) released by a variety of cell types have been shown to act as a natural delivery system for bioactive molecules such as RNAs and proteins. EV therapy holds great promise as a safe and cell‐free therapy for many immunological and degenerative diseases. However, translation to clinical application is limited by several factors, including insufficient large‐scale manufacturing technologies and low yield. We have developed a novel drug delivery platform technology, BioDrone™, based on cell‐derived vesicles (CDVs) produced from diverse cell sources by using a proprietary extrusion process. This extrusion technology generates nanosized vesicles in far greater numbers than naturally obtained EVs. We demonstrate that the CDVs are surrounded by a lipid bilayer membrane with a correct membrane topology. Physical, biochemical and functional characterisation results demonstrate the potential of CDVs to act as effective therapeutics. Umbilical cord mesenchymal stem cell (UCMSC)‐derived CDVs exhibit a biological activity that is similar to UCMSCs or UCMSC‐derived EVs. Lastly, we present the establishment of a GMP‐compliant process to allow the production of a large number of UCMSC‐CDVs in a reproducible manner. GMP‐compliant manufacturing of CDVs will facilitate the preclinical and clinical evaluation of these emerging therapeutics in anti‐inflammatory or regenerative medicine. This study also represents a crucial step in the development of this novel drug delivery platform based on CDVs.

Lipedema is a chronic, progressive disease of adipose tissue with lack of consistent diagnostic criteria. The aim of this study was a thorough comparative characterization of extracellular microRNAs (miRNAs) from the stromal vascular fraction (SVF) of healthy and lipedema adipose tissue. For this, we analyzed 187 extracellular miRNAs in concentrated conditioned medium (cCM) and specifically in small extracellular vesicles (sEVs) enriched thereof by size exclusion chromatography. No significant difference in median particle size and concentration was observed between sEV fractions in healthy and lipedema. We found the majority of miRNAs located predominantly in cCM compared to sEV enriched fraction. Surprisingly, hierarchical clustering of the most variant miRNAs showed that only sEVmiRNA profiles-but not cCMmiRNAs-were impacted by lipedema. Seven sEVmiRNAs (miR-16-5p, miR-29a-3p, miR-24-3p, miR-454-p, miR-144-5p, miR-130a-3p, let-7c-5p) were differently regulated in lipedema and healthy individuals, whereas only one cCMmiRNA (miR-188-5p) was significantly downregulated in lipedema. Comparing SVF from healthy and lipedema patients, we identified sEVs as the lipedema relevant miRNA fraction. This study contributes to identify the potential role of SVF secreted miRNAs in lipedema. Lipedema is a chronic, progressive disease characterized by bilateral, symmetrical, disproportional deposition of adipose tissue in the extremities and buttocks 1. Patients suffer from pain, reduced joint mobility, hematoma, edema and psychological impacts 2. It was first described in 1940 as a connective tissue disorder, characterized by fluid being collected in the interstitium instead of entering into lymphatics 3. This excess fluid in the interstitium potentially leads to growth of adipose tissue and hypoxia, which in turn might enhance angiogenesis of pathologic vessels 4,5. The area of lymphatic vessels and the number of blood vessels were found increased in non-obese lipedema patients compared to controls 6. Examination of adipose tissue from lipedema patients demonstrated hypertrophic adipocytes, crown-like structures and increased number of macrophages 6-8. Besides functioning as an energy storage, white adipose tissue (WAT) responds differentially to physiological and pathological metabolic changes by secreting a large diversity of proteins, hormones, lipids, non-coding ribonucleic acids (RNAs)-including microRNAs (miRNAs)-and extracellular vesicles (EVs) 9,10. Small EVs (sEVs) are a fraction of 70-150 nm sized, membrane-enclosed particles, which contain cell-type specific proteins, enzymes, growth factors, cytokines, lipids, as well as coding and non-coding RNAs. It has been repeatedly reported, that WAT-derived vesicular miRNAs are involved in metabolic regulations 11,12 and adipose tissue is considered a significant source of circulating sEV-miRNAs 11. By acting in an autocrine, paracrine as well as systemic manner, these factors can contribute to metabolic abnormalities, modulation of osteogenic differentiation, inhibition of...