Shimada Michiko, Yamabe Hideaki, Osawa Hiroshi, Nakamura Norio, Kumasaka Ryuichiro, Murakami Reiichi, Fujita Takeshi, Osanai Tomohiro, Okumura Ken
Department of Nephrology, Hirosaki University Graduate School of Medicine, 5 Zaifu-cho, Hirosaki, Japan.
Nephrology (Carlton). 2009 Apr;14(2):171-8. doi: 10.1111/j.1440-1797.2008.01033.x.
Matrix metalloproteinases (MMP) affect matrix remodelling, and extracellular matrix metalloproteinase inducer (EMMPRIN) has been reported to increase the levels of several MMP. However, the expression of EMMPRIN in the human kidney and its regulatory mechanisms are not well known. In this study, we examined EMMPRIN expression in the human kidney with the biopsied specimens, cultured proximal tubular epithelial cells (PTEC) and human mesangial cells (HMC).
EMMPRIN expression was examined by immunofluorescent (IF) study, reverse transcription polymerase chain reaction, western blotting and enzyme-linked immunosorbent assay. We also examined soluble EMMPRIN in the conditioned medium of PTEC stimulated by various agents and its effect in the activities of MMP-2 and MMP-9. Also, IF study in the several kidney diseases was performed to elucidate its role in pathological condition.
EMMPRIN expression was diffusely observed in the tubular epithelial cells of most patients and healthy adults, but was never observed in glomeruli. Cultured PTEC expressed EMMPRIN, while HMC did not. Soluble EMMPRIN was also detected by enzyme-linked immunosorbent assay in the conditioned medium of PTEC. Epidermal growth factor (50 ng/mL) and phorbol 12-myristate 13-acetate (10(-7) mol/L) stimulated the secretion of soluble EMMPRIN and increased the MMP-2 activity, although these agents did not increase the level of EMMPRIN mRNA. From the IF study, EMMPRIN expression was shown to decrease in tubulointerstitial nephritis.
EMMPRIN is widely distributed in the tubular epithelial cells of the adult human kidney and may regulate MMP-2 activity via its secretion from PTEC.
基质金属蛋白酶（MMP）影响基质重塑，且据报道细胞外基质金属蛋白酶诱导剂（EMMPRIN）可增加多种MMP的水平。然而，EMMPRIN在人肾脏中的表达及其调控机制尚不清楚。在本研究中，我们用活检标本、培养的近端肾小管上皮细胞（PTEC）和人系膜细胞（HMC）检测了人肾脏中EMMPRIN的表达。
通过免疫荧光（IF）研究、逆转录聚合酶链反应、蛋白质印迹法和酶联免疫吸附测定法检测EMMPRIN的表达。我们还检测了各种试剂刺激的PTEC条件培养基中的可溶性EMMPRIN及其对MMP-2和MMP-9活性的影响。此外，对几种肾脏疾病进行了IF研究，以阐明其在病理状态中的作用。
在大多数患者和健康成年人的肾小管上皮细胞中广泛观察到EMMPRIN表达，但在肾小球中从未观察到。培养的PTEC表达EMMPRIN，而HMC不表达。通过酶联免疫吸附测定法在PTEC的条件培养基中也检测到了可溶性EMMPRIN。表皮生长因子（50 ng/mL）和佛波酯（10⁻⁷ mol/L）刺激可溶性EMMPRIN的分泌并增加MMP-2活性，尽管这些试剂并未增加EMMPRIN mRNA的水平。从IF研究来看，在肾小管间质性肾炎中EMMPRIN表达降低。
EMMPRIN广泛分布于成年人类肾脏的肾小管上皮细胞中，并可能通过从PTEC分泌来调节MMP-2活性。
