Regulatory role of GSK3β in the activation of NF-κB and modulation of cytokine levels in Burkholderia pseudomallei-infected PBMC isolated from Streptozotocin-induced diabetic animals
- Author:
Maniam, P
;
Nurul Aiezzah, Z
;
Mohamed, R
;
Embi, N
;
Hasidah, M.S.
- Publication Type:Journal Article
- From:Tropical Biomedicine
2015;32(1):36-48
- CountryMalaysia
- Language:English
-
Abstract:
Increased susceptibility of diabetics to melioidosis, a disease caused by the
Burkholderia pseudomallei bacterium is believed to be attributed to dysfunction of the
innate immune system. However, the underlying mechanism of the innate susceptibility is not
well-understood. Glycogen synthase kinase-3β (GSK3β) plays an important role in the innate
inflammatory response caused by bacterial pathogens. The present study was conducted to
investigate the effects of GSK3β inhibition by LiCl on levels of pro- and anti-inflammatory
cytokines; and the activity of transcription factor NF-κB in B. pseudomallei-infected peripheral
blood mononuclear cells (PBMC) derived from diabetic-induced and normal Sprague Dawley
rats. In addition, the effects of LiCl on intracellular bacterial counts were also investigated.
Infection of PBMC from diabetic and normal rats with B. pseudomallei resulted in elevated
levels of cytokines (TNF-α, IL-12 and IL-10) and phosphorylation of NF-κB in both cell types.
Intracellular bacterial counts decreased with time in both cell types during infection. However
bacterial clearance was less prominent in diabetic PBMC. Burkholderia pseudomallei infection
also caused inactivation (Ser9 phosphorylation) of GSK3β in normal PBMC, an effect absent
in infected diabetic PBMC. Inhibition of GSK3β by LiCl lowered the levels of pro-inflammatory
cytokines (TNF-α and IL-12) in both normal and diabetic PBMC. Similarly, phosphorylated NF-
κB (pNF-κB) levels in both cell types were decreased with LiCl treatment. Also, LiCl was able
to significantly decrease the intracellular bacterial count in normal as well as diabetic PBMC.
Interestingly, the levels of anti-inflammatory cytokine IL-10 in both normal and diabetic
PBMC were further elevated with GSK3β inhibition. More importantly, GSK3β in infected
diabetic PBMC was inactivated as in their non-diabetic counterparts upon LiCl treatment.
Taken together, our results suggest that inhibition of dysregulated GSK3β in diabetic PBMC
resulted in the inactivation of NF-κB and modulation of inflammatory cytokine levels. This is
evidence that dysregulation of GSK3β is a contributing factor in the molecular basis of innate
dysfunction and susceptibility of diabetic host to melioidosis infection.
- Full text:W020150519510124068310.pdf
