Human Chromogranin A (19-131) ELISA Kit

Carboxypeptidase A6 (CPA6) is an extracellular matrix metallocarboxypeptidase that modulates peptide and protein function by removal of hydrophobic C-terminal amino acids. Mutations in the human CPA6 gene that reduce enzymatic activity in the extracellular matrix are associated with febrile seizures, temporal lobe epilepsy, and juvenile myoclonic epilepsy. The characterization of these human mutations suggests a dominant mode of inheritance by haploinsufficiency through loss of function mutations, however the total number of humans with pathologic mutations in CPA6 identified to date remains small. To better understand the relationship between CPA6 and seizures we investigated the effects of morpholino knockdown of cpa6 mRNA in zebrafish (Danio rerio) larvae. Knockdown of cpa6 mRNA resulted in resistance to the effect of seizure-inducing drugs pentylenetetrazole and pilocarpine on swimming behaviors. Knockdown of cpa6 mRNA also reduced the levels of mRNAs encoding neuropeptide precursors (bdnf, npy, chga, pcsk1nl, tac1, nts, edn1), a neuropeptide processing enzyme (cpe), transcription factor (c-fos), and molecules implicated in glutamatergic signaling (grin1a and slc1a2b). Treatment of zebrafish embryos with 60 mM pilocarpine for 1 hour led to reductions in levels of many of the same mRNAs when measured 1 day after pilocarpine exposure, except for c-fos which was elevated 1 day after pilocarpine treatment. Pilocarpine treatment, like cpa6 knockdown, led to a reduced sensitivity to pentylenetetrazole when tested 1 day after pilocarpine treatment. Taken together, these results add to mounting evidence that peptidergic systems participate in the biological effects of seizure-inducing drugs, and are the first in vivo demonstration of the molecular and behavioral consequences of cpa6 insufficiency.

Stress mobilizes elements from the neuroendocrine system to modulate immune responses. Cholinergic stimulation via nicotinic receptor (nAchR) is a major neuroendocrine signaling axis associated with the stress response whose specific effects on the immune system are unknown. Here, we show that nAchR activation by topical agonist application or deletion of the nAChR antagonist catestatin (Chga(-/-) reduced antimicrobial peptide (AMP) activity in skin extracts and increased susceptibility to methicillin-resistant Staphylococcus aureus and Group A Streptococcus infections. The adverse effects on AMP expression and infection were rescued by topical application of a nAChR antagonist. Stress-induced nAChR activation increased infection in wild-type, but not Chga(-/-) or cathelicidin-deficient, mice. These data identify a mechanism for the negative regulation of host-innate AMP response to infection through cholinergic activation and indicate nAChR-mediated cathelicidin dysregulation as a potential mechanism for increased susceptibility to infection following prolonged stress or nicotine use.