Follicular DNA Damage and Pesticide Exposure Among Latinx Children in Rural and Urban Communities

Abstract

The intersectional risks of children in United States immigrant communities include environmental exposures. Pesticide exposures and their biological outcomes are not well characterized in this population group. We assessed pesticide exposure and related these exposures to DNA double-strand breaks (DSBs) in Latinx children from rural, farmworker families (FW; N = 30) and from urban, non-farmworker families (NFW; N = 15) living in North Carolina. DSBs were quantified in hair follicular cells by immunostaining of 53BP1, and exposure to 72 pesticides and pesticide degradation products were determined using silicone wristbands. Cholinesterase activity was measured in blood samples. DSB frequencies were higher in FW compared to NFW children. Seasonal effects were detected in the FW group, with highest DNA damage levels in April-June and lowest levels in October-November. Acetylcholinesterase depression had the same seasonality and correlated with follicular DNA damage. Organophosphate pesticides were more frequently detected in FW than in NFW children. Participants with organophosphate detections had increased follicular DNA damage compared to participants without organophosphate detection. Follicular DNA damage did not correlate with organochlorine or pyrethroid detections and was not associated with the total number of pesticides detected in the wristbands. These results point to rural disparities in pesticide exposures and their outcomes in children from vulnerable immigrant communities. They suggest that among the different classes of pesticides, organophosphates have the strongest genotoxic effects. Assessing pesticide exposures and their consequences at the individual level is key to environmental surveillance programs. To this end, the minimally invasive combined approach used here is particularly well suited for children.

Supplementary information: The online version contains supplementary material available at 10.1007/s12403-023-00609-1.

Keywords: Community-based participatory research; Farmworkers; Genome instability; Health equity; Personalized sampling; Pesticides.

Fig. 1

Detection of DNA breaks in hair follicles from Latinx children living in non-farmworker (NFW) and farmworker (FW) families. A Low-magnification images illustrating the different parts of a plucked hair follicle (brightfield; BF) and the presence of follicular cells (DAPI). Scale bar, 500 µm. B Tip of a hair follicle stained for the DNA double-strand break marker 53BP1. Nuclei were labeled with DAPI, and actin was labeled with phalloidin. Arrowheads indicate DNA damage foci in the enlarged image. Scale bar, 50 µm. C Quantification of 53BP1 DSB foci in hair follicles from NFW and FW children. *, P = 0.029 (Mann–Whitney). D Comparison of DSB levels in FW children at different times of collection. *, P = 0.030 (Kruskal–Wallis and Dunn’s multiple comparison test). E 53BP1 foci counts in hair follicles collected during the period from July to September 2021. P = 0.026 (Mann–Whitney)

Fig. 2

Effect of sun exposure on follicular DNA damage. A–B Questionnaire data on how often children from non-farmworker (NFW) and farmworker (FW) families played outside in the sun in the last seven days preceding the hair collection (A) and, for those who did play outside, if a hat (sun protection) was worn (B). Questionnaire data was missing for one FW participant. Statistical comparison using Fischer exact test. C 53BP1 foci counts for the different sun exposure categories. ns, P = 0.92 (Kruskal–Wallis). Green circles represent NFW children and blue squares represent FW children

Fig. 3

Number of pesticides detected in the wristband samplers worn by children from non-farmworker (NFW) and farmworker (FW) families. The graphs present total detections (A), as well as organochlorine (OC) (B), organophosphate (OP) (C), and pyrethroid (Pyreth.) (D) detections. *, P < 0.05; ns, not significant (Mann–Whitney)

Fig. 4

DNA double-strand breaks and exposures to pesticides. A 53BP1 foci in hair follicles as a function of the total number of pesticides detected using personal wristband samplers. B-D Comparison of 53BP1 foci numbers in participants with or without detection of organochlorine (OC) (B), organophosphate (OP) (C), and pyrethroid (Pyreth.) (D) pesticides. P values are indicated (Mann–Whitney). E Relationship between acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activity (µmol/min/ml). F AChE and BChE activity by study location, i.e., in children from non-farmworker (NFW) and farmworker (FW) families. ***, P = 0.0003; ns, not significant (Mann–Whitney). G Seasonality of AChE and BChE activity. Repeated measures (N = 4–9 per participant) are plotted according to the time (month) of measurement. *, P = 0.010; **, P = 0.0014 (Kruskal–Wallis and Dunn’s multiple comparison test). H Association between A/BChE and 53BP1 foci in hair follicles. Spearman’s r coefficients and P values are indicated

Fig. 5

DNA double-strand break induction by chlorpyrifos in epithelial cells. A Visualization of DSBs in HMT-3522 S1 breast epithelial cells expressing the minimal focus forming region of 53BP1 fused to the mCherry fluorescent protein (mCh-53BP1_ct). The arrowhead points to a DSB focus in the fluorescent image. BF, brightfield. Scale bar, 20 µm. B Quantification of mCh-53BP1_ct in S1 cells treated with vehicle (ethanol) or with chlorpyrifos (CPF, 1 µg/ml) for 24 h. *, P = 0.011 (Mann–Whitney). C Detection of DSBs in follicular cells after 24 h treatments with vehicle or CPF. DSBs were defined as overlapping 53BP1 and H2AX foci, as illustrated in the inset (arrow). *, P < 0.05; ****, P < 0.0001 (Kruskal–Wallis and Dunn’s multiple comparison test)