# Lactiplantibacillus plantarum K8 lysates regulate hypoxia-induced gene expression

## TL;DR

This study shows that lysates from Lactiplantibacillus plantarum K8 can suppress hypoxia-induced gene expression, potentially offering a natural remedy for hypoxia-related conditions.

## Contribution

The novel finding is that K8 lysates regulate hypoxia-induced gene expression through a non-canonical pathway involving HIF1α.

## Key findings

- K8 lysates significantly downregulate hypoxia-induced HIF1α accumulation in cancer cell lines.
- K8 lysates suppress the transcription of HIF1α target genes like p21, GLUT1, and ALDOC under hypoxia.
- K8 lysates decrease PHD2 and VHL protein expression, suggesting a non-canonical regulation of HIF1α stability.

## Abstract

Hypoxic responses have been implicated in critical pathologies, including inflammation, immunity, and tumorigenesis. Recently, efforts to identify effective natural remedies and health supplements are increasing. Previous studies have reported that the cell lysates and the cell wall-bound lipoteichoic acids of Lactiplantibacillus plantarum K8 (K8) exert anti-inflammatory and immunomodulative effects. However, the effect of K8 on cellular hypoxic responses remains unknown. In this study, we found that K8 lysates had a potent suppressive effect on gene expression under hypoxia. K8 lysates markedly downregulated hypoxia-induced HIF1α accumulation in the human bone marrow and lung cancer cell lines, SH-SY5Y and H460. Consequently, the transcription of known HIF1α target genes, such as p21, GLUT1, and ALDOC, was notably suppressed in the K8 lysate supplement and purified lipoteichoic acids of K8, upon hypoxic induction. Intriguingly, K8 lysates decreased the expression of PHD2 and VHL proteins, which are responsible for HIF1α destabilization under normoxic conditions, suggesting that K8 may regulate HIF1α stability in a non-canonical pathway. Overall, our results suggest that K8 lysates desensitize the cells to hypoxic stresses and suppress HIF1α-mediated hypoxic gene activation.