PROTEIN-KINASE-C HAS 2 DIFFERENT MAJOR ROLES IN LATTICE COMPACTION ENHANCED BY CEREBROSPINAL-FLUID FROM PATIENTS WITH SUBARACHNOID HEMORRHAGE

Background and Purpose Compaction of extracellular matrix (ECM) lattic es by cultured fibroblasts was accelerated by cerebrospinal fluid (CSF ) from patients with subarachnoid hemorrhage (SAH). The rate of accele ration was significantly related to the clinical grade of vasospasm. H owever, the mechanism remains unclear. Evidence exists for an importan t role in cerebral vasospasm for protein kinase C (PKC). The purpose o f this study was to help clarify whether PKC has a role in contraction of the ECM. Methods We studied the effects of a myristoylated PKC pep tide inhibitor g-Phe-Ala-Arg-Lys-Gly-Ala-Leu-Arg-Gln-Lys-Asn-Val) (PKC peptide inhibitor), (5-isoquinolinesulfonyl)-homopiperazine (HA-1077) (inhibitor of protein kinase A, myosin light-chain kinase, and protei n kinase G), 7-deacetyl-6-(N-acetylglycyl)-forskolin (forskolin) (aden yl cyclase activator), and diacylglycerol-lactone (DAG-lactone) (PKC a ctivator) on fibroblast-populated collagen lattice compaction with or without CSF from SAH patients. Four sets of fibroblasts were used: thr ee explanted from skin and one from cerebral artery. Results Moderate and high concentrations of PKC peptide inhibitor inhibited lattice com paction with or without acceleration by CSF. Low concentration of PKC peptide inhibitor enhanced acceleration by CSF but had no effects with out CSF. HA-1077 could not inhibit lattice compaction. Forskolin inhib ited compaction. DAG-lactone accelerated compaction in early phases. C onclusions In the mechanism of acceleration of contraction of ECM unde r the influence of CSF, PKC seems to have two different roles. Protein kinase A and myosin light-chain kinase apparently play more minor rol es than PKC in the mechanism, but no evidence was found of a role for protein kinase G activation in matrix compaction.