# Function of HIF-1α in Regulation of Antioxidative Stress of Tribolium castaneum Under Hypoxia

## TL;DR

This study explores how the HIF-1α gene helps red flour beetles survive in low-oxygen environments and suggests targeting this gene could improve pest control.

## Contribution

The study reveals the role of HIF-1α in regulating antioxidant defenses and DNA repair in T. castaneum under hypoxia.

## Key findings

- HIF-1α expression increases in beetles under hypoxia and is structurally conserved across insect species.
- Knockdown of HIF-1α leads to higher larval mortality, DNA damage, and reduced antioxidant gene expression.
- HIF-1α suppression results in increased ROS accumulation and lipid peroxidation.

## Abstract

The red flour beetle (Tribolium castaneum) is a major pest that damages stored grains worldwide. Low-oxygen conditions (hypoxia) in sealed storage systems represent an environmentally friendly method for controlling this pest. However, beetles are capable of surviving under hypoxic conditions. In this study, we investigated a key gene, HIF-1α, which enables the response to hypoxia. We found that HIF-1α is structurally conserved across different insect species. When beetle larvae were exposed to severe hypoxia (2% oxygen), expression of HIF-1α was increased. To understand its function, we used RNA interference to knockdown HIF-1α and observed the response of beetles to hypoxia. Results showed that beetles without HIF-1α were more likely to die under hypoxia and suffered serious DNA damage. Genes responsible for repairing oxidative damage were suppressed. These findings showed that HIF-1α helps T. castaneum survive under hypoxic environments by regulating antioxidant defenses and repairing DNA damage. Targeting HIF-1α might lead to more effective pest control strategies for stored grain protection.

Hypoxia-inducible factor (HIF) is recognized as a key transcription factor via regulating a variety of molecular responses to hypoxia, although the details are still unclear. In this study, based on bioinformatics analysis, the expression of the HIF-1α gene in T. castaneum (TcHIF-1α) under hypoxic treatments was determined. After TcHIF-1α knockdown by injecting dsRNA, larval mortality, the expression levels of oxidative stress-related genes, and enzymatic activities were measured; DNA damage was also evaluated through single cell gel electrophoresis. The result indicated that TcHIF-1α is highly conserved in structure. TcHIF-1α exhibited distinct temporal patterns, with a peak after 72 h of exposure to 2% O2. Following TcHIF-1α knockdown, a significant increase in larval mortality (17.44 ± 5.91%) and moderate DNA damage level was found. This might be accompanied by ROS accumulation, lipid peroxidation (LPO), and suppression of antioxidant enzymatic activities. The expression of genes involved in ROS synthesis (e.g., NOX) was significantly upregulated, whereas genes responsible for mitigating oxidative stress (e.g., OGG1, XRCC1, PARP1, SOD1a) were markedly downregulated. These findings elucidate the critical role of HIF-1α in insect hypoxia adaptation by regulating the antioxidative stress, highlighting its potential as a promising target for developing novel pest control strategies.