Abousaad Shaymaa, Ahmed Faihaa, Abouzeid Ayman, Adhiambo Christine, Ongeri Elimelda Moige
Department of Kinesiology, College of Health and Human Sciences, North Carolina A&T State University, Greensboro, NC, 27411, USA.
Department of Clinical Sciences, The College of Veterinary Medicine, North Carolina State University, Raleigh, NC, 27606, USA.
BMC Nephrol. 2025 Aug 18;26(1):467. doi: 10.1186/s12882-025-04224-x.
Inflammation plays a central role in the progression of kidney injury induced by ischemia/reperfusion (IR). Meprin metalloproteinases have been implicated in the pathophysiology of IR-induced kidney injury. Existing data from in vitro and in vivo studies show that meprins modulate interleukin-6 (IL-6)-mediated inflammation via proteolytic processing of IL-6 and its receptor. IL-6 trans-signaling induces proliferation through either Mitogen-activated protein kinase /extracellular signal-regulated kinase (MAPK/ERK) or Phosphatidylinositol 3-Kinase/ protein kinase B (PI3K/AKT) pathway or in crosstalk with AKT/ERK. We previously showed that meprin β modulates cellular survival B-Cell Lymphoma/Leukemia 2 (BCL-2) through IL-6/Janus kinase/ Signal Transducer and Activator of Transcription (IL-6/JAK/STAT) signaling pathway in IR-induced kidney injury. However, it's not known how meprin β modulation of the IL-6 signaling pathway impacts the cellular proliferation in IR-induced acute kidney injury. The goal of the current study was to determine how meprin β modulation of the IL-6 signaling pathway impacts downstream cellular proliferation in IR-induced kidney injury.
We induced Ischemia/Reperfusion injury with unilateral IR as a model of renal inflammation in wild-type (WT) and meprin β knockout (βKO) mice, with the contralateral kidneys serving as controls. The mice were sacrificed at 96 h post-IR, and kidney tissue processed for evaluation by RT-PCR and immunohistochemistry. Statistical analysis utilized two-way ANOVA.
RT-PCR data showed a significant increase in mRNA levels for IL-6 and proliferating cell nuclear antigen (PCNA) in WT and βKO mice at 96 h-post IR when compared to WT control kidneys. However, the baseline mRNA levels for PCNA were significantly higher in βKO when compared to WT kidneys. Immunohistochemical data showed significant increases in IL-6, PCNA, p-AKT and p-ERK in select tubules in both genotypes at 96 h post-IR when compared to control kidneys for each genotype. Data from immunofluorescence counterstaining of kidney tissues revealed that at 96 hours post-IR, IL-6, PCNA, p-AKT, and p-ERK were primarily expressed in meprin β-expressing proximal tubules (PTs), where meprins are abundantly present. However, high levels of IL-6 were also present in the lumen of PTs and DTs from WT and βKO kidneys at 96 h post-IR, suggesting increased release/shedding into filtrate and subsequently into urine.
In conclusion, this study highlights the role of meprin β activity in regulating cellular proliferation through PCNA regulation, driven by the IL-6-mediated AKT/ERK signaling pathway during the recovery phase following IR-induced kidney injury.
Not applicable.
炎症在缺血/再灌注（IR）诱导的肾损伤进展中起核心作用。膜型金属蛋白酶在IR诱导的肾损伤病理生理学中具有重要意义。体外和体内研究的现有数据表明，膜型金属蛋白酶通过对白细胞介素-6（IL-6）及其受体的蛋白水解加工来调节IL-6介导的炎症。IL-6转信号传导通过丝裂原活化蛋白激酶/细胞外信号调节激酶（MAPK/ERK）或磷脂酰肌醇3-激酶/蛋白激酶B（PI3K/AKT）途径诱导增殖，或与AKT/ERK相互作用。我们之前表明，在IR诱导的肾损伤中，膜型金属蛋白酶β通过IL-6/Janus激酶/信号转导和转录激活因子（IL-6/JAK/STAT）信号通路调节细胞存活蛋白B细胞淋巴瘤/白血病2（BCL-2）。然而，尚不清楚膜型金属蛋白酶β对IL-6信号通路的调节如何影响IR诱导的急性肾损伤中的细胞增殖。本研究的目的是确定膜型金属蛋白酶β对IL-6信号通路的调节如何影响IR诱导的肾损伤中的下游细胞增殖。
我们以单侧IR诱导缺血/再灌注损伤作为野生型（WT）和膜型金属蛋白酶β基因敲除（βKO）小鼠肾炎症模型，对侧肾脏作为对照。在IR后96小时处死小鼠，对肾组织进行处理以通过RT-PCR和免疫组织化学进行评估。统计分析采用双向方差分析。
RT-PCR数据显示，与WT对照肾脏相比，WT和βKO小鼠在IR后96小时IL-6和增殖细胞核抗原（PCNA）的mRNA水平显著升高。然而，与WT肾脏相比，βKO中PCNA的基线mRNA水平显著更高。免疫组织化学数据显示，与每种基因型的对照肾脏相比，两种基因型在IR后96小时选定肾小管中IL-6、PCNA、p-AKT和p-ERK显著增加。肾组织免疫荧光复染数据显示，在IR后96小时，IL-6、PCNA、p-AKT和p-ERK主要在表达膜型金属蛋白酶β的近端小管（PT）中表达，PT中膜型金属蛋白酶大量存在。然而，在IR后96小时，WT和βKO肾脏的PT和远端小管（DT）管腔中也存在高水平的IL-6，表明释放/脱落增加进入滤液并随后进入尿液。
总之，本研究强调了膜型金属蛋白酶β活性在IR诱导的肾损伤恢复阶段通过IL-6介导的AKT/ERK信号通路驱动的PCNA调节来调节细胞增殖中的作用。
不适用。
