Presented by:Raunak RoyM.Sc. Zoology; Semester IVDepartment of Zoology, University of Delhi

Vasoactive Intestinal Peptide : Role in the Neuroendocrine Modulation of Immunity

Discovery of VIP

Discovery of VIP contd.

Identification of VIP in the CNS and PNS by Said & Rosenberg in 1976.

Since then VIP been recognized as widely distributed neuropeptide whose major actions are either as a neurotransmitter or neuromodulator.

The isolation of VIP & its designation mainly as a neurotransmitter was fortunate due to the presence of dense enteric plexus of nerves

In recent years, the implication of VIP as an important immunomodulatory with pleiotropic actions has raised the question whether it could be considered a cytokine due to its predominantly local actions in either paracrine or autocrine manner..

“..therefore, if Said & Mutt had discovered VIP in the immune system, instead of the intestine, VIP could have been considered a type 2 cytokine instead of a neuropeptide..”

(Delgado M. & Ganea D., 2003)

Discovery of VIP contd.

The VIP gene

Cytogenetic location: 6q25.2

The VIP gene contd.

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Ref.: World j biol chem. 2011 june 26; 2(6): 146-160.

•Exon 1: 5’-UTR of the mRNA, •Exon 2: signal peptide, •Exon 3: N-terminal peptide, •Exon 4: PHM, •Exon 5: VIP, •Exon 6: C-terminal peptide•Exon 7: 3’-UTR of the mRNA

• Bodner et al. (1985) had shown that VIP & PHM-27 are encoded by adjacent exons

• Linder et al. (1987) determined that the VIP gene contains 7 exons spanning ~ 9kb(8837 bp)

The VIP gene contd.

The VIP gene contd.*mRNA expression does not always necessarily indicate translation into the peptide..

Evidence supporting differential protein processing –The fact that all brain cells showing VIP mRNA expression ALSO show PHM mRNA expression Differential regulation at protein level.

(Linder et al., 1987; Card et al. 1988)