Targeting hexokinase 1 alleviates NLRP3-mediated inflammation in apical periodontitis: A laboratory investigation

The aim of the study was to explore whether hexokinase 1 (HK1) is involved in the inhibition of inflammation mediated by nucleotide-binding oligomerization domain-like receptor protein 3 (NLRP3) signalling pathway in the development of apical periodontitis (AP).

Human AP tissues and normal control tissues were collected in the clinic. First, the levels of glucose, pyruvate, lactate and hexokinase activity were examined in human AP tissues. ECAR and OCR were further measured to detect the level of glycolysis in vitro model of inflammation, which established with lipopolysaccharide (LPS)-stimulated RAW264.7 cell line. Secondly, the expression of HK1, NLRP3, caspase-1 and interleukin (IL)-1β were measured by Western blot, immunohistochemistry or RT-qPCR. Finally, lentiviral short hairpin RNA (shRNA) silencing technique or the inhibitor 2-deoxy-d-glucose (2-DG) were used to further detect the relationship between HK1-mediated glycolysis and NLRP3-mediated inflammation in the development of AP in vitro.

Initially, the level of glycolysis was significantly increased in human AP tissues. Subsequently, the expression of HK1, NLRP3, caspase-1 and IL-1β were upregulated significantly in human AP tissues. Furthermore, in the model of AP in vitro, a high level of glycolysis and the high expression of HK1, NLRP3, caspase-1 and IL-1β was observed. Finally, the expression of NLRP3, caspase-1 and IL-1β mediated by LPS stimulation was significantly reduced via HK1 knockdown or 2-DG treatment in vitro.

Our data support that HK1-mediated glycolysis plays a crucial role in the development of AP via upregulating the NLRP3 signalling pathway. Moreover, targeting HK1 may contribute to prevent the progression of AP, which has a potential clinical translation.