DOI: 10.5061/dryad.mw6m9062w
title: Artificial space weathering to mimic solar wind enhances the toxicity of lunar dust simulants in human lung cells

description: During NASA's Apollo missions, inhalation of dust particles from
 lunar regolith was identified as a potential occupational hazard
 for astronauts. These fine particles adhered tightly
 to spacesuits and were unavoidably brought into the living areas
 of the spacecraft. Apollo astronauts reported that exposure to the dust
 caused intense respiratory and ocular irritation. This problem is
 a potential challenge for the Artemis Program, which aims to return humans
 to the Moon for extended stays in this decade. Since lunar dust is
 “weathered” by space radiation, solar wind, and the incessant
 bombardment of micrometeorites, we investigated whether treatment of lunar
 regolith simulants to mimic space weathering enhanced their toxicity. Two
 such simulants were employed in this research, Lunar Mare
 Simulant-1 (LMS-1), and Lunar Highlands Simulant-1 (LHS-1), which were
 added to cultures of human lung epithelial cells (A549) to simulate lung
 exposure to the dusts. In addition to pulverization, previously shown to
 increase dust toxicity sharply, the simulants were exposed to hydrogen gas
 at high temperature as a proxy for solar wind exposure. This treatment
 further increased the toxicity of both simulants, as measured by
 the disruption of mitochondrial function, and damage to DNA both in
 mitochondria and in the nucleus. By testing the effects of supplementing
 the cells with an antioxidant (N-acetylcysteine), we showed that a
 substantial component of this toxicity arises from free radicals. It
 remains to be determined to what extent the radicals arise from the dust
 itself, as opposed to their active generation by inflammatory processes in
 the treated cells.
description: # Artificial Space Weathering to Mimic Solar Wind Enhances the Toxicity of
 Lunar Dust Simulants in Human Lung Cells. Published in GeoHealth.
 **[Plain Language
 Summary]** With the Artemis program, humans will soon return to explore
 the Moon. However, lunar surface dust has toxic potential that must be
 assessed in order to clarify short-term and long-term health risks for
 Artemis astronauts. Numerous studies indicate that Moon dust has chemical
 and physical properties that may strongly affect dust toxicity. Unlike
 terrestrial dust, lunar regolith experiences “space weathering” under a
 vacuum, including the effects of solar wind, which further modifies the
 bulk and surface properties of this dust. In this work, we used two lunar
 dust simulant materials that were chemically treated to mimic the effects
 of space weathering. This treatment strongly increased all the toxic
 effects of both simulants: cell killing, mitochondrial dysfunction, and
 damage to DNA. Other experiments point to free radicals as a significant
 component of these effects. Future work will address whether these
 radicals arise from the simulants themselves or are generated by cellular
 activity. ## Authors **Jamie Hsing-Ming Chang** Department of
 Pharmacological Sciences, Renaissance School of Medicine, Stony Brook
 University, NY 11794, USA 
 **Zhouyiyuan Xue** Department of Pharmacological Sciences, Renaissance
 School of Medicine, Stony Brook University, NY 11794, USA
 **Jack Bauer** Department of
 Pharmacological Sciences, Renaissance School of Medicine, Stony Brook
 University, NY 11794, USA **Barbara
 Wehle** Department of Pharmacological Sciences, Renaissance School of
 Medicine, Stony Brook University, NY 11794, USA
 **Donald A. Hendrix** National High Magnetic
 Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
 **Tristan Catalano** Department of Geosciences,
 Stony Brook University, NY 11794, USA
 **Joel A. Hurowitz** Department of
 Geosciences, Stony Brook University, NY 11794, USA
 **Hanna Nekvasil** Department of
 Geosciences, Stony Brook University, NY 11794, USA
 **Bruce Demple** Departments of
 Pharmacological Sciences and of Radiation Oncology, Renaissance School of
 Medicine, Stony Brook University, NY 11794, USA
 ## File Description from Figure 1-6
 **Fig. 1.zip**: In this .zip file, you will see raw files for Figure 1 in
 the related GeoHealth manuscript with folders of **"102821bu"**
 and **"102821x"** under **"SEM images and reports."**
 The former (folder **"102821bu"**) includes SEM images of
 non-reduced LMS-1 (folder **"LMS_1"**), reduced LMS-1 (folder
 **"LMS_1_R"**), LHS-1 (folder **"LHS_1"**), and
 reduced LHS-1 (folder **"LHS_1_R"**), and the later (folder
 **"102821x"**) includes spectra files of LHS-1 (folder
 **"LHS_1x"**), reduced LHS-1 (folder **"LHS_1_Rx"**)
 and reduced LMS-1 (folder **"LMS_1_Rx"**), and a .xlsx with a
 table of proving of decrease of size after grinding of lunar dust
 simulants. **Figure 2, 3, 4 & 6.xlsx**: In this .xlsx file with 14
 sheets, you will see raw data for Figure 2, 3, 4A, 4B, 6B, and the cell
 survival for the concentration of N-acetylcysteine (abbreviated as
 **NAC**) we used in the related GeoHealth manuscript. *For sheets of
 **"NAC survival testing"**, "**Fig. 2A - untreated
 LMS", "Fig. 2A - reduced LMS", "Fig. 2B - untreated
 LHS", "Fig. 2B - reduced LHS", "Fig. 2C",** and
 **"Fig. 2D"***, the **UPPER** part showed the RAW cell
 concentration with condition listed upper left (e.g. "A549 1 h
 LHS-1" stands for A549 cell survival after 1 h-exposure to LHS-1) ,
 and the **LOWER** part showed the NORMALIZED cell survival after negative
 control (labeled "Control") is set to 100% with P values
 provided. *In the sheet of* ***"NAC survival testing"***, 70.70
 in RED showed that 5 mM NAC is the highest and also the best concentration
 for pretreating A549 cells before the dust challenge as it is the highest
 survival among different NAC concentrations. *In the sheet of*
 ***"Fig. 2C"*** *and **"Fig. 2D"**,* the experimental
 groups pretreated with NAC were compared to their own controls. *For
 sheets of **"Fig. 3A - LMS-1"**, **"Fig. 3A -
 LHS-1"**, **"Fig. 3B - LMS-1"**, and **"Fig. 3B -
 LHS-1"***, RAW fluorescent readings of Long PCR and Short PCR were
 shown in "Picogreen Readout," then "Net Value" were
 calculated after subtracting "PCR Blank" for each group. Later,
 the ratios were first calculated by dividing the "Net Value" of
 Long PCR to Short PCR, and then normalizing the controls to 1 with p
 values provided. *In the sheet of* ***"Fig. 3B - LMS-1"*** *and
 **"Fig. 3B - LHS-1"**,* the experimental groups pretreated with
 NAC were compared to their own controls. *For sheets of* ***"Fig.
 4A"*** *and **"Fig. 4B"***, RAW fluorescent readings of
 MitoSOX Red were shown under "510 nm&gt;580 nm", the blanks were
 then subtracted, and controls are normalized to 1 with p values provided.
 The experimental groups pretreated with NAC were compared to their own
 controls. *For sheets of* ***"Fig. 6B"***, RAW "Tail
 Moment" values were provided by using ImageJ and OpenComet as
 described in the manuscript, and then the negative control was normalized
 to 1 with p values provided. **Figure 6A.zip**: In this .zip file, you
 will see raw image .tif files for Figure 6A in the related GeoHealth
 manuscript in the designated folder of "(Negative) Control",
 "Positive Control (Etoposide)", "LMS-1", "Reduced
 LMS-1", "LHS-1", and "Reduced LHS-1". **Figure
 5.pzf**: You will need GraphPad Prism to open this file to gain access to
 raw data points of oxygen consumption continuously detected up to 72 hours
 after exposure to LMS-1 in A549 cells. Each group usually contains 4
 replicates, except for R-0.5 mg/cm<sup>2</sup> with only 2
 replicates and 0.2 mg/cm<sup>2</sup> with only 3 replicates
 because of technical issues. Please refer to the captions of Figure 5 in
 the related GeoHealth manuscript.