Genes required for survival in microgravity revealed by genome-wide yeast deletion collections cultured during spaceflight

Spaceflight is a unique environment with profound effects on biological systems including tissue redistribution and musculoskeletal stresses. However, the more subtle biological effects of spaceflight on cells and organisms are difficult to measure in a systematic, unbiased manner. Here we test the utility of the molecularly barcoded yeast deletion collection to provide a quantitative assessment of the effects of microgravity on a model organism. We developed robust hardware to screen, in parallel, the complete collection of ~4800 homozygous and ~5900 heterozygous (including ~1100 single-copy deletions of essential genes) yeast deletion strains, each carrying unique DNA that acts as strain identifiers. We compared strain fitness for the homozygous and heterozygous yeast deletion collections grown in spaceflight and ground, as well as plus and minus hyperosmolar sodium chloride, providing a second additive stressor. The genome-wide sensitivity profiles obtained from these treatments were then queried for their similarity to a compendium of drugs whose effects on the yeast collection have been previously reported. We found that the effects of spaceflight have high concordance with the effects of DNA-damaging agents and changes in redox state, suggesting mechanisms by which spaceflight may negatively affect cell fitness

Role of Shear Stress on Renal Proximal Tubular Cells for Nephrotoxicity Assays

Drug-induced nephrotoxicity causes huge morbidity and mortality at massive financial cost. The greatest burden of drug-induced acute kidney injury falls on the proximal tubular cells. To maintain their structure and function, renal proximal tubular cells need the shear stress from tubular fluid flow. Diverse techniques to reintroduce shear stress have been studied in a variety of proximal tubular like cell culture models. These studies often have limited replicates because of the huge cost of equipment and do not report all relevant parameters to allow reproduction and comparison of studies between labs. This review codifies the techniques used to reintroduce shear stress, the cell lines utilized, and the biological outcomes reported. Further, we propose a set of interventions to enhance future cell biology understanding of nephrotoxicity using cell culture models

IDENTIFICATION OF IMMUNE COMPLEXES IN CULTURE SUPERNATANTS CONTAINING HIDDEN ANTIBODIES REACTIVE WITH

rheumatoid arthritis (RA), the immunoglobulin (Ig)M anti-Fc, anti-Fab', and antistreptokinase-streptodornase (SKSD) produced by peripheral blood lymphocytes (PBL) were measured at intervals from 1 to 19 d in culture. PBL from 17 seropositive patients with active RA and 30 age-matched controls were evaluated. Within the first 24 h, PBL from six of eight patients released>30 ng IgM anti-Fc, even in the absence of pokeweed mitogen (PWM). This early release of Ab was blocked by cycloheximide. With or without PWM, PBL from normal donors did not release IgM anti-Fc until after 3-5 d in vitro. By day 9, unstimulated PBL from seven patients made>100 ng IgM anti-Fc. Unstimulated PBL from normals never made>95 ng of this Ab. When PWM was added, PBL from normal donors released as much IgM anti-Fc as was found in RA donor cultures. Paradoxically, addition of PWM to PBL of RA patients suppressed release of IgM anti-Fc in 4 of 17 cases to levels significantly below those found in unstimulated cultures of the same cells. Without PWM, PBL from RA donors frequently Address reprint requests to Dr. Rossen. Received for publication 6 April 1981 and in revised for

Effects of Space Flight on Mouse Liver versus Kidney: Gene Pathway Analyses

Understanding genome wide, tissue-specific, and spaceflight-induced changes in gene expression is critical to develop effective countermeasures. Transcriptome analysis has been performed on diverse tissues harvested from animals flown in space, but not the kidney. We determined the genome wide gene expression using a gene array analysis of kidney and liver tissue from mice flown in space for 12 days versus ground based control animals. By comparing the transcriptome of liver and kidney from animals flown in space versus ground control animals, we tested a unique hypothesis: Are there common gene expression pathways activated in multiple tissue types in response to spaceflight stimuli? Although there were tissue-specific changes, both liver and kidney overexpressed genes in the same four areas: (a) cellular responses to peptides, hormones, and nitrogen/organonitrogen compounds; (b) apoptosis and cell death; (c) fat cell differentiation and (d) negative regulation of protein kinase