Characterization and location of secretory phospholipase A2 groups IIE, V, and X in the rat brain

Abstract

Secretory phospholipases A(2) (sPLA(2)) form a diverse family of enzymes involved in a variety of physiologic and pathologic processes. Common among all sPLA(2) is the ability to cleave the second position of phospholipids, thereby releasing fatty acid and a lysophospholipid. Several sPLA(2) have been cloned and characterized in various tissues and receptors have been identified. In the nervous system, sPLA(2) groups IB, IIA, IIE, IIF, V, and XII have been identified, and binding sites for sPLA(2) have been found. Here, we report sPLA(2)-IIE and sPLA(2)-X in rat brain as well as in neurons in primary culture. We furthermore confirm the presence of sPLA(2)-V in rat brain and demonstrate the presence of sPLA(2)-V in primary neuronal cultures. The distribution of sPLA(2)-IIE, V, and -X seems to be mainly neuronal, with the highest abundance occurring in the cerebral cortex and hippocampus. We also find that sPLA(2)-IIE, -V, and -X are differentially induced by kainic acid. This study supports the concept that sPLA(2) heterogeneity in brain is functionally relevant and responsive to seizures.

The emerging role of group VI calcium-independent phospholipase A2 in releasing docosahexaenoic acid from brain phospholipids

“…On a broad level, the mammalian PLA 2 isoforms differ with respect to their tissue and cellular distribution, substrate specificities, and calcium requirements, and interested readers should consult other reviews for more details (36)(37)(38)(39)(40)(41), including PLA 2 nomenclature/classification (41,42). The isoforms identified in the brain to date include groups IVA, IVB, and IVC calcium-dependent cytosolic phospholipase A 2 (cPLA 2 ), groups IIA, IIC, IIE, V, and X calcium-dependent secretory phospholipase A 2 (sPLA 2 ), and groups VIA and VIB calcium-independent phospholipase A 2 (iPLA 2 ) (43)(44)(45)(46)(47)(48)(49). It is worth noting that the mouse strains C57BL/6, 129/Sv, and B10.RIII have a naturally occurring missense mutation in the gene encoding for the group IIA sPLA 2 (45,(50)(51)(52).…”

Kainate Receptors Mediate Regulated Exocytosis of Secretory Phospholipase A2 in SH-SY5Y Neuroblastoma Cells

“…sPLA 2 -IIA, -IIC, -IID, -IIE, -IIF and -V are clustered on the same chromosome locus (1p34-p36) [4] . sPLA 2 -IB, -IIA, -IIC, -IIE, -III, -V and -X are found in the central nervous system (CNS) [5][6][7] . Relatively high levels of sPLA 2 activity are detected in the hippocampus, medulla oblongata and pons [8] .…”

A possible role for sPLA2 in oligodendrocyte death and spinal cord injury.

“…While others have demonstrated the presence of selected sPLA 2 mRNAs in the brain (Molloy et al, 1998, Kolko et al, 2005, Kolko et al, 2006 (Han et al, 2003), this was the first study to directly link free radical injury to sPLA 2 -IIA production. Other authors had already confirmed that sPLA 2 -IIA present in μM levels could trigger apoptosis in cultured neurons (Yagami et al, 2002b) and we showed that exogenously adding sPLA 2 triggered a loss of oligodendrocyte process extensions at low doses and death at μM levels as well.…”

“…The distribution of sPLA 2 -IIE, V, and X seems to be mainly neuronal, with the highest abundance occurring in the cerebral cortex and hippocampus (Kolko et al, 2006). In the spinal cord, sPLA 2 activity was detected in the normal rat spinal cord homogenate .…”

“…sPLA 2 -IIA is associated with the endoplasmic reticulum in perinuclear regions of Purkinje cell somata and sPLA 2 -V was localized in Bergmann glia cells (Shirai and Ito, 2004). Recently, Kolko, et al, found the presence of sPLA 2 -IIE, V, and X in the rat brain as well as in neurons in primary cultures using RT-PCR, in situ hybridization, and immunohistochemistry (Kolko et al, 2006).…”