Article

Curcumin induces human cathelicidin antimicrobial peptide gene expression through a vitamin D receptor-independent pathway.

Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA; Department of Biochemistry and Biophysics, Oregon State University, Corvallis, OR 97331, USA.
The Journal of nutritional biochemistry (impact factor: 4.29). 07/2012; DOI:10.1016/j.jnutbio.2012.04.002
Source: PubMed

ABSTRACT The vitamin D receptor (VDR) mediates the pleiotropic biologic effects of 1α,25 dihydroxy-vitamin D(3). Recent in vitro studies suggested that curcumin and polyunsaturated fatty acids (PUFAs) also bind to VDR with low affinity. As potential ligands for the VDR, we hypothesized that curcumin and PUFAs would induce expression of known VDR target genes in cells. In this study, we tested whether these compounds regulated two important VDR target genes - human cathelicidin antimicrobial peptide (CAMP) and 1,25-dihydroxyvitamin D(3) 24-hydroxylase (CYP24A1) - in human monocytic cell line U937, colon cancer cell line HT-29 and keratinocyte cell line HaCaT. We demonstrated that PUFAs failed to induce CAMP or CYP24A1 mRNA expression in all three cell lines, but curcumin up-regulated CAMP mRNA and protein levels in U937 cells. Curcumin treatment induced CAMP promoter activity from a luciferase reporter construct lacking the VDR binding site and did not increase binding of the VDR to the CAMP promoter as determined by chromatin immunoprecipitation assays. These findings indicate that induction of CAMP by curcumin occurs through a vitamin D receptor-independent manner. We conclude that PUFAs and curcumin do not function as ligands for the VDR.

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    Article: The possible roles of vitamin D and curcumin in treating gonorrhea.
    Dima A Youssef, Alan N Peiris, Jim L Kelley, William B Grant
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    ABSTRACT: Drug-resistant gonorrhea, Neisseria gonorrhoeae (N. gonorrhoeae), is an emerging concern, especially because the risk of bladder cancer is associated with this infection. N. gonorrhoeae suppresses T-helper 1(Th1) and Th2 responses and enhances Th17 responses via a mechanism involving transforming growth factor-beta (TGF-β) and regulatory T cells. Blockade of TGF-β alleviates the suppression of specific anti-gonococcal responses and allows Th1 and Th2 responses to emerge with concomitant boosting of immune memory and protective immunity. Gonorrhea activates nuclear factor kappaB (NF-kappaB), which plays a critical role in signal-transduction pathways involved in inflammation. The innate immune system can eventually clear gonorrhea. Vitamin D is emerging as a potential, powerful, anti-microbial agent with these effects: it supports the innate immune system in combating bacterial infections; it decreases levels of TGF-β and NF-kappaB activation; and it induces production of LL-37 (cathelicidin), which has antimicrobial and antiendotoxin properties. In addition, via an independent vitamin D receptor pathway, curcumin also induces LL-37 production, inhibiting N. gonorrhoeae-induced NF-kappaB signaling and inducing autophagy. Therefore, vitamin D and curcumin taken together may be useful in combating both normal and drug-resistant gonorrhea. Moreover, the possible synergy between these two agents in improving outcomes is worthy of additional investigation.
    Medical Hypotheses 04/2013; · 1.39 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.

Keywords

chromatin immunoprecipitation assays
 
Curcumin treatment induced CAMP promoter activity
 
curcumin up-regulated CAMP mRNA
 
CYP24A1 mRNA expression
 
human cathelicidin antimicrobial peptide
 
increase binding
 
induce CAMP
 
keratinocyte cell line HaCaT
 
luciferase reporter
 
pleiotropic biologic effects
 
polyunsaturated fatty acids
 
potential ligands
 
protein levels
 
three cell lines
 
VDR
 
VDR binding site
 
VDR target genes
 
vitamin D receptor
 
vitamin D receptor-independent manner
 
vitro studies