The water-soluble fraction (<10 kD) of bee venom (Apis mellifera) produces inhibitory effect on apical transporters in renal proximal tubule cells.
Human envenomation caused by bee stings has been reported to cause acute renal failure and the pathogenetic mechanisms of these renal functional changes are still unclear. Bee venom is also a complex mixture of enzymes and proteins. Thus, this study was conducted to examine the effects of bee venom (BV, Apis mellifera) fractions on apical transporters' activity and its related signal pathways in primary cultured renal proximal tubule cells. Whole BV was extracted into three fractions according to solubility [a water-soluble fraction (BVA), an ethylacetate-soluble fraction (BVE), and a hexane-soluble fraction (BVH)]. BVA fraction was further separated to three portions according to molecular weights: BF1 (>20 kD), BF2 (10-20 kD), and BF3 (<10 kD). Each fraction was treated to the PTCs to the ratio of BV (1 microg/ml). BVA (930 ng/ml) significantly decreased cell viability, but BVH (27 ng/ml) and BVE (43 ng/ml) did not. BF3 (710 ng/ml) among BVA fractions predominantly decreased cell viability and inhibited alpha-methyl-D-glucopyranoside (alpha-MG), phosphate (Pi), and Na(+) uptake. In addition, BF3 increased [(3)H] arachidonic acid release, lipid peroxide formation, and Ca(2+) uptake. These effects of BF3 were blocked by mepacrine and AACOCF(3) (phospholipase A(2) inhibitors) or N-acetylcysteine, vitamin C, and vitamin E (antioxidants). In conclusion, BF3 (<10 kD) among BV fractions is the most effective portion in BV-induced inhibition of alpha-MG, P(i), and Na(+) uptake and these effects of BF3 are associated with phospholipase A(2)-oxidative stress-Ca(2+) signal cascade in the primary cultured rabbit renal proximal tubule cells.
Han
Ho Jae
HJ
Department of Veterinary Physiology, College of Veterinary Medicine, Chonnam National University, Kwangju, Korea. hjhan@chonnam.ac.kr
Yoon
Byeong Cheol
BC
Oh
Young Joon
YJ
Park
Soo Hyun
SH
Lee
Jang Hern
JH
Mar
Woong Chon
WC
D000818:Animals; D016718:Arachidonic Acid / Q000378:metabolism; D001514:Bee Venoms / Q000378:metabolism / Q000494:pharmacology*; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002470:Cell Survival; D007687:Kidney Tubules, Proximal / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D008757:Methylglucosides / Q000493:pharmacokinetics; D018384:Oxidative Stress / Q000187:drug effects; D010710:Phosphates / Q000493:pharmacokinetics; D010741:Phospholipases A / Q000378:metabolism; D011817:Rabbits; D015398:Signal Transduction / Q000187:drug effects; D012964:Sodium / Q000493:pharmacokinetics; D012995:Solubility; D014316:Tritium
D001514:Bee Venoms; D008757:Methylglucosides; D010710:Phosphates; D014316:Tritium; D016718:Arachidonic Acid; C027020:methylglucoside; D012964:Sodium; D010741:Phospholipases A; D002118:Calcium