Method for Predicting Respiratory Toxicity of Compounds
The invention provides methods for analyzing and predicting the in vivo respiratory toxicity of a compound (e.g., pharmaceutical, biological, cosmetic, or chemical compounds) or composition comprising a combination of an in vitro mammalian cell model with multiple endpoint analysis, and time and concentration response curves. The methods allow the determination of a predicted in vivo respiratory toxicity value of a compound without the use of animals, with a high degree of accuracy. The methods comprise detecting any combination of cell viability markers and expression levels of genes implicated in respiratory toxicity and/or sensitization, such as pro-inflammatory response genes, combining the viability and gene expression level data with concentration response and time response data, conducting a computational analysis, and comparing test compound data to a database of known respiratory toxicants/sensitizers to predict and/or analyze the respiratory toxicity. An indication of organ specificity is provided by a toxicity index, which is determined by comparing mean IC 50 values in lung cells to mean IC 50 values in liver cells.
1 . A method for predicting the in vivo respiratory toxicity of a compound, comprising:
(a) culturing mammalian cells;
(b) contacting the mammalian cells with a concentration of the compound;
(c) measuring the expression level of one or more marker genes in the mammalian cells after contacting the cells with the compound;
(d) monitoring multiple endpoints of cell viability and general cell health;
(e) conducting a computational analysis of the concentration of the compound used to contact the cells, and the measured expression level(s) of the one or more marker genes; and
(f) determining a predicted in vivo respiratory toxicity value based on the computational analysis.
2 . The method of claim 1 , wherein the mammalian cells are human cells selected from the group: three dimensional synthetic airway models derived from epithelial cells from tracheal or bronchial tissue, or both; lung cells, NCI-H460, NCI-H549, NCI-H661, NCI-H292, BEAS-2B; Clara cell lines; Clara cells in culture; precision cut tissue slices of lung;
and combination cultures thereof
3 . The method of claim 1 , wherein the cells are contacted with varying dosages of compound.
4 . The method of claim 1 , wherein the marker gene(s) are selected from the group consisting of: CYP1A1; Bax; Bcl2; TNFα; TGFβ; IL-1a; IL-6; and IL-8; quinone reductase; CD-86; aldo-keto reductase; thioredoxin; and thioredoxin reductase.
5 . The method of claim 1 , wherein the multiple endpoints comprise at least one of cellular structure, cell viability, and oxidative stress.
6 . The method of claim 1 , wherein the computational analysis comprises data from a set of known lung or respiratory toxicants and known exposure levels and toxicity categories.
7 . A method for screening a compound for in vivo respiratory toxicity comprising:
(a) culturing mammalian cells;
(b) contacting the mammalian cells with a concentration of the compound;
(c) measuring the expression level of one or more marker genes in the mammalian cells after contacting the cells with the compound;
(d) monitoring multiple endpoints of cell viability and general cell health;
(e) conducting a computational analysis of the concentration of the compound used to contact the cells, and the measured expression level(s) of the one or more marker genes;
(f) determining a predicted in vivo respiratory toxicity value based on the computational analysis; and
(g) determining whether the toxicity value of the compound falls within acceptable limits for the particular in vivo use.
8 . The method of claim 7 , wherein the mammalian cells are human cells selected from the group: three dimensional synthetic airway models derived from epithelial cells from tracheal or bronchial tissue, or both; lung cells, NCI-H460, NCI-H549, NCI-H661, NCI-H292, BEAS-2B; Clara cell lines; Clara cells in culture; precision cut tissue slices of lung; and combination cultures thereof
9 . The method of claim 7 wherein the cells are contacted with varying dosages of compound.
10 . The method of claim 7 , wherein the marker gene(s) are selected from the group consisting of: quinone reductase; CYP1A1; Bax; Bcl2; TNFα; TGFβ; IL-1a; IL-6; and IL-8; CD-86; aldo-keto reductase; thioredoxin; and thioredoxin reductase.
11 . The method of claim 7 , wherein the multiple endpoints comprise at least one of cellular structure, cell viability, and oxidative stress.
12 . The method of claim 7 , wherein the computational analysis comprises data from a set of known lung or respiratory toxicants and known exposure levels and toxicity categories.
13 . A method for categorizing the in vivo respiratory toxicity of a compound, comprising:
(a) culturing mammalian cells;
(b) contacting the mammalian cells with a concentration of the compound;
(c) measuring the expression level of one or more marker genes in the mammalian cells after contacting the cells with the compound;
(d) monitoring multiple endpoints of cell viability and general cell health;
(e) conducting a computational analysis of the concentration of the compound used to contact the cells, and the measured expression level(s) of the one or more marker genes; and
(f) determining a predicted in vivo respiratory toxicity value based on the computational analysis;
wherein the computational analysis (e) comprises a comparison of the data from the compound with data gathered from at least two compounds with known respiratory toxicity profiles,
wherein the two compounds with known respiratory toxicity profiles are classified as a respiratory sensitizer, a respiratory irritant, or a respiratory corrosive, wherein the at least two compounds are not members of the same toxicity profile class.
14 . The method of claim 13 , wherein the mammalian cells are human cells selected from the group: three dimensional synthetic airway models derived from epithelial cells from tracheal or bronchial tissue, or both; lung cells, NCI-H460, NCI-H549, NCI-H661, NCI-H292, BEAS-2B; Clara cell lines; Clara cells in culture; precision cut tissue slices of lung; and combination cultures thereof
15 . The method of claim 13 , wherein the cells are contacted with varying dosages of compound.
16 . The method of claim 13 , wherein the marker gene(s) are selected from the group consisting of: quinone reductase; CYP1A1; Bax; Bcl2; TNFα; TGFβ; IL-1a; IL-6; and IL-8; CD-86; aldo-keto reductase; thioredoxin; and thioredoxin reductase.
17 . The method of claim 13 , wherein the multiple endpoints comprise at least one of cellular structure, cell viability, and oxidative stress.
18 . The method of claim 13 , wherein the computational analysis comprises data from a set of known lung or respiratory toxicants and known exposure levels and toxicity categories.
19 . A kit comprising reagents for
(a) reagents for measuring the expression level of one or more marker genes in mammalian cells in culture;
(b) reagents for monitoring multiple endpoints of cell viability and general cell health;
(c) optional software for executing instructions on a CPU that performs a computational analysis of the measured expression level(s) of the one or more marker genes, and the cell viability and general cell health data; and
(d) instructions for use of the kit.