Substance P at the neuro-immune crosstalk in the modulation of inflammation, asthma and antimicrobial host defense.

Substance P, a neuropeptide belonging to the tachykinin family is a pleiotropic peptide with specific neural activities and involved in immunomodulation and antimicrobial host defense. It has been found to modulate a variety of inflammatory processes, including acute pancreatitis, sepsis, systemic inflammatory response syndrome and asthma. Also notably, substance P shares common bio-physical and -chemical properties such as low molecular mass, cathionicity and amphipathicity with antimicrobial peptides. It is therefore suggested to take part in host defense at specialized locations. The review aims to highlight undated understanding on substance P in inflammation, allergy and its antimicrobial activities with potential implications in infection and host defense. Therapeutic implications of the peptide, modulators of peptide expression and receptor signalling will be highlighted in each topic. Taken together, these topics will be of significant values for future pharmaceutical investigation and application of the field.