Biology subjects

Matei, I.

Publications and source records attributed to Matei, I..

4 recordsLinked to original sources

bioRxiv2023

Advancement in Cellular Topographic and Nanoparticle Capture Imaging by High Resolution Microscopy Incorporating a Freeze-Drying and Gaseous Nitrogen-based Approach

Scanning electron microscopy (SEM) offers an unparalleled view of the membrane topography of mammalian cells by using a conventional osmium (OsO4) and ethanol-based tissue preparation. However, conventional SEM methods limit optimal resolution due to ethanol and lipid interactions and interfere with visualization of fluorescent reporter proteins. Therefore, SEM correlative light and electron microscopy (CLEM) has been hindered by the adverse effects of ethanol and OsO4 on retention of fluorescence signals. To overcome this technological gap in achieving high-resolution SEM and retain fluorescent reporter signals, we developed a freeze-drying method with gaseous nitrogen (FDGN). We demonstrate that FDGN preserves cyto-architecture to allow visualization of detailed membrane topography while retaining fluorescent signals and that FDGN processing can be used in conjunction with a variety of high-resolution imaging systems to enable collection and validation of unique, high-quality data from these approaches. In particular, we show that FDGN coupled with high resolution microscopy provided detailed insight into viral or tumor-derived extracellular vesicle (TEV)-host cell interactions and may aid in designing new approaches to intervene during viral infection or to harness TEVs as therapeutic agents.

cell biology↗

bioRxiv2023

Collection of Biospecimens from the Inspiration4 Mission Establishes the Standards for the Space Omics and Medical Atlas (SOMA)

The SpaceX Inspiration4 mission provided a unique opportunity to study the impact of spaceflight on the human body. Biospecimen samples were collected from the crew at different stages of the mission, including before (L-92, L-44, L-3 days), during (FD1, FD2, FD3), and after (R+1, R+45, R+82, R+194 days) spaceflight, creating a longitudinal sample set. The collection process included samples such as venous blood, capillary dried blood spot cards, saliva, urine, stool, body swabs, capsule swabs, SpaceX Dragon capsule HEPA filter, and skin biopsies, which were processed to obtain aliquots of serum, plasma, extracellular vesicles, and peripheral blood mononuclear cells. All samples were then processed in clinical and research laboratories for optimal isolation and testing of DNA, RNA, proteins, metabolites, and other biomolecules. This paper describes the complete set of collected biospecimens, their processing steps, and long-term biobanking methods, which enable future molecular assays and testing. As such, this study details a robust framework for obtaining and preserving high-quality human, microbial, and environmental samples for aerospace medicine in the Space Omics and Medical Atlas (SOMA) initiative, which can also aid future experiments in human spaceflight and space biology.

molecular biology↗

bioRxiv2022

Mast cells impair melanoma cell homing and metastasis by inhibiting HMGA1 secretion.

Metastatic disease is the major cause of death from cancer. From the primary tumor, cells remotely prepare the environment of the future metastatic sites by secreted factors and extracellular vesicles. During this process, known as pre-metastatic niche formation, immune cells play a crucial role. Mast cells are hematopoietic bone marrow-derived innate immune cells whose function in lung immune response to invading tumors remains to be defined. We found reduced melanoma lung metastasis in mast cell deficient mouse models (Wsh and MCTP5-Cre-RDTR), supporting a pro-metastatic role for mast cells in vivo. However, due to evidence pointing to their antitumorigenic role, we studied the impact of mast cells in melanoma cell function in vitro. Surprisingly, in vitro co-culture of bone-marrow derived mast cells with melanoma cells showed that they have an intrinsic anti-metastatic activity. Mass spectrometry analysis of melanoma-mast cell co-cultures secretome showed that HMGA1 secretion by melanoma cells was significantly impaired. Consistently, HMGA1 knock down in B16-F10 cells reduced their metastatic capacity in vivo. Importantly, analysis of HMGA1 expression in human melanoma tumors showed that metastatic tumors with high HMGA1 expression are associated with reduced overall and disease-free survival. Moreover, we show that HMGA1 is reduced in the nuclei and enriched in the cytoplasm of melanoma metastatic lesions when compared to primary tumors. These data suggest that high HMGA1 expression and secretion from melanoma cells promotes metastatic behavior. Targeting HMGA1 expression intrinsically or extrinsically by mast cells actions reduce melanoma metastasis. Our results pave the way to the use of HMGA1 as anti-metastatic target in melanoma as previously suggested in other cancer types.

cancer biology↗

bioRxiv2020

Cell-free DNA (cfDNA) and exosome profiling from a year-long humanspaceflight reveals circulating biomarkers

The health impact of prolonged space flight on the human body is not well understood. Liquid biopsies based on cell-free DNA (cfDNA) or exosome analysis provide a noninvasive approach to monitor the dynamics of genomic, epigenomic and proteomic biomarkers, and the occurrence of DNA damage, physiological stress, and immune responses. To study the molecular consequences of spaceflight we profiled cfDNA isolated from plasma of an astronaut (TW) during a year-long mission on the International Space Station (ISS), sampling before, during, and after spaceflight, and compared the results to cfDNA profiling of the subjects identical twin (HR) who remained on Earth, as well as healthy donors. We characterized cfDNA concentration and fragment size, and the positioning of nucleosomes on cfDNA, observing a significant increase in the proportion of cell-free mitochondrial DNA inflight, suggesting that cf-mtDNA is a potential biomarker for space flight-associated stress, and that this result was robust to ambient transit from the International Space Station (ISS). Analysis of exosomes isolated from post-flight plasma revealed a 30-fold increase in circulating exosomes and distinct exosomal protein cargo, including brain-derived peptides, in TW compared to HR and all known controls. This study provides the first longitudinal analysis of astronaut cfDNA during spaceflight, as well as the first exosome profiles, and highlights cf-mtDNA levels as a potential biomarker for physiological stress or immune system responses related to microgravity, radiation exposure, and other unique environmental conditions on the ISS.

cell biology↗