# RNA modifications by paternal exposure to arsenic and intergenerational effects on sperm quality

> **NIH NIH R01** · UNIV OF ARKANSAS FOR MED SCIS · 2023 · $499,577

## Abstract

PROJECT SUMMARY
Inorganic arsenic (iAs) produces significant reproductive toxicity in adult males leading to decreased sperm
quality. Aside from workplace exposure, individuals are exposed to high levels of iAs near hazardous waste sites
and in geographic areas enriched with iAs. A recent study revealed that transient prenatal exposure to a high
dose of iAs impaired sperm quality in multiple generations. However, it is not known whether paternal exposures
to environmentally relevant dose of iAs during adolescence or early-life (gestation to weaning) produce adverse
inheritable reproductive outcomes. We posit that adolescence and early-life are windows of susceptibility during
which exposure to iAs negatively impacts not only the individuals being exposed but also their offspring. However,
the molecular mechanisms mediating paternal intergenerational transmission of exposure-induced traits remain
unclear. Recently, sperm-borne small-RNAs and their specific 5'-methylcytosine (m5C) modifications were shown
to mediate the paternal transmission of diet-induced disorders. Yet, similar studies on environmental toxicants such
as iAs are absent. In our pilot study, we discovered iAs-induced changes in pseudouridine (Ψ) and m5C abundance
in sperm small-RNAs. Ψ and m5C were found to be the most abundant RNA modifications in sperm small-RNAs,
and we hypothesize that these modifications mediate the paternal inheritance of poor sperm quality associated
with iAs exposure, particularly during the developmental windows of adolescence (Aim 1) and early life (gestation
to weaning) (Aim 2). We will determine if adolescent (Aim 1A) and early-life (Aim 2A) iAs exposure are windows
of susceptibility conferring the intergenerational inheritance of impaired sperm quality. We will identify the
mediating role of sperm small-RNAs and their modifications, Ψ and m5C, in adolescent (Aim 1B) and early-life
(Aim 2B) exposure-induced paternal inheritance of impaired sperm quality by performing zygotic microinjection
(ZI) of sperm small-RNA isolated from exposed or control mice to generate offspring from naïve zygotes. We
expect the offspring of the adolescent exposure group to have poorer sperm quality, as in exposed fathers and
sons produced by natural mating. To validate the functional role of specific modifications in our sperm phenotype
inheritance model, we will isolate Ψ- and m5C-enriched sperm small-RNA fractions by RNA immunoprecipitation
for zygotic microinjection. We will determine if microinjection of specific modification-enriched sperm small-RNAs
during adolescent (Aim 1C) and early-life (Aim 2C) can reproduce the paternal sperm phenotype. We expect the
ZI-produced offspring exposed to Ψ- or m5C-enriched sperm small-RNAs from adolescent and/or early-life
exposure groups can recapitulate the poor sperm quality phenotypes. We will use Nanopore native RNAseq to
map sperm Ψ and m5C modifications and identify small-RNA populations associated with the exposure window-
spec...

## Key facts

- **NIH application ID:** 10615715
- **Project number:** 5R01ES032675-02
- **Recipient organization:** UNIV OF ARKANSAS FOR MED SCIS
- **Principal Investigator:** Shuk-Mei Ho
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2023
- **Award amount:** $499,577
- **Award type:** 5
- **Project period:** 2022-04-29 → 2027-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10615715

## Citation

> US National Institutes of Health, RePORTER application 10615715, RNA modifications by paternal exposure to arsenic and intergenerational effects on sperm quality (5R01ES032675-02). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10615715. Licensed CC0.

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