Kumar P, Williams JN, Durkin KL, Heckels JE, Friedmann PS, Healy E, Christodoulides M. Neuropeptide alpha-MSH exerts pro-inflammatory effects on Neisseria meningitidis infection in vitro.
Inflamm Res 2009;
59:105-13. [PMID:
19685205 DOI:
10.1007/s00011-009-0076-9]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2009] [Revised: 06/30/2009] [Accepted: 07/27/2009] [Indexed: 11/25/2022] Open
Abstract
OBJECTIVE AND DESIGN
alpha-Melanoycte stimulating hormone (alpha-MSH), a neuropeptide hormone with reported anti-microbial and immuno-modulatory properties in vitro, has previously been detected in the cerebrospinal fluid of children with bacterial meningitis. We investigated the therapeutic effects of alpha-MSH administration on Neisseria meningitidis infection of human meningeal cell cultures in vitro.
MATERIALS AND METHODS
Meningeal cell lines (n = 2) were infected with meningococci (10(2)-10(8) cfu/monolayer), isolated bacterial outer membranes (OM; 1 microg/ml) or lipo-oligosaccharide (LOS; 1 microg/ml) with and without alpha-MSH (10(-5)-10 microM). Bacterial adherence was quantified at 6 h, and cytokine production and microbicidal activity of alpha-MSH for meningococci were assessed at 24 h.
RESULTS
Compared with infection by meningococci alone, alpha-MSH (10 microM) up-regulated secretion of IL-6 and IL-8 (mean values increased from approximately 33 to 60 ng/ml), RANTES (mean values increased from approximately 26 to 105 ng/ml) and GM-CSF (mean values increased from approximately 0.3 to 1 ng/ml; P < 0.05). Upregulated secretion correlated with a neuropeptide-mediated rapid and >5-fold increase (P < 0.05) in bacterial adherence to cells and was dependent on OM components including LOS acting synergistically with alpha-MSH. Meningococci were resistant to the anti-microbial activity of alpha-MSH at all concentrations tested.
CONCLUSIONS
Our study demonstrates that a potentially therapeutic neuropeptide exerts pro-inflammatory effects during meningococcal infection in vitro and its use in the treatment of meningitis is contra-indicated.
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