Engineering topics

Juran, Cassandra

Publications and source records attributed to Juran, Cassandra.

2 records

NASA NTRS2018

CDKN1a/p21 Plays a Critical Role in Suppressing Stem Cell Regenerative Potential During Aging

Unloading during spaceflight is known to adversely affect mammalian physiology. Mechanical stimulation is required for repair and regeneration by stem cell lineages to maintain tissue health and mass. CDKN1a/p21 functions as a potent cell cycle arrest molecule and we previously found that CDKN1a/p21 was overexpressed in mouse bone during 15-days of spaceflight on STS-131 and localized to osteoprecursor cells in the femur. Therefore, we hypothesized that altered expression of CDKN1a/p21 leads to an arrest of bone formation during spaceflight in response to altered load. To study CDKN1a/p21 and its role in stem cell-based tissue regeneration, we use a CDKN1a/p21 knockout (KO) mouse to investigate the impact on bone structure, osteoprogenitor proliferation, and mineralized nodule formation. We have shown that bone marrow stem cells isolated from juvenile (11-week-old) and skeletally mature (18-week-old) KO mice have an increased bone formation potential as evidenced by increased proliferation and mineralization rates. In addition, we have shown that juvenile KO mice display significantly increased bone volume fraction (BV/TV) relative to wildtype (WT) mice, but not in skeletally mature KO mice, indicating increased resorption and bone turnover in adult mice. To more closely examine age differences in the KO mouse, we will study a wider spectrum of mice ranging from 4 weeks to 12 months in age. To do this, we will analyze differences in bone morphometric parameters using MicroCT and osteoblastogenesis assays. The pelvis, femur, and tibia are key in distributing weight and we expect to see altered remodeling and stem cell potential with age. In combination with histomorphometry, these results will help elucidate the complex mechanisms underlying bone tissue maintenance and stem cell regeneration.

stem cells↗

NASA NTRS2018

Monitoring Astronaut Health with DNA Sequencing

In recent years microbe a plethora of microbe populations have been identified onboard the ISS (International Space Station). Approaches for real-time tracking of microbes for routine housekeeping and food/water safety monitoring will be critical for mission safety and crew health on future longer duration missions to the Moon or Mars. This work is a proof-of-concept study demonstrating an end-to-end phylogenetic identification and full genome sequencing effort of multiple microbial populations. Our methodology utilized the ISS flight-certified WetLab-2 molecular toolbox and the Biomolecule Sequencer projects for real-time end-to-end on-orbit microbial biological samples processing and molecular analysis with real time results generated utilizing only field "offline" analytic software. For this experiment we colony-cultured several ISS isolated microorganisms before generation of the pre-sequencing library via the automated VolTRAX device which enabled high library turnover with little wet-bench activity or potential future costly astronaut time. The pre-sequencing library is diluted in loading buffer and injected into the MinION sample port, drawn into the nanopore window by capillary action, and sequenced using the MinKnown. 16S and full genome alignment, nucleotide matching, gene identification, and phylogenetic sorting was accomplished utilizing the Epi2me software and the offline NCBI Blast viral, microbiome, and human somatic databases. In short, the methodologies developed herein replace the myriad of specific, often highly targeted microbiological tests used in the clinical laboratory, which would be difficult if not impossible to currently implement aboard the ISS or in deep space, with a single metagenomics test.

genomics↗