Boals Avery G, Collier Daniel M, Romero Julian R, Hillard Cecilia J, Park Frank
University of Tennessee Health Science Center, College of Pharmacy, Memphis, Tennessee, USA.
Faculty of Experimental Sciences, Universidad Francisco de Vitoria, Pozuelo de Alarcón, Spain.
Cannabis Cannabinoid Res. 2025 Jun;10(3):400-408. doi: 10.1089/can.2024.0142. Epub 2024 Oct 9.
Although cannabinoid type 2 (CB2) receptor activity is known to promote diverse biological functions in the kidney, published data regarding CB2 receptor protein levels and cellular distribution within the kidney is inconsistent. The goal of the present study was to investigate the changes of CB2 in the kidney obtained from mice exposed to various forms of kidney injury using a genetic mouse model expressing green fluorescent protein (GFP) driven by the endogenous cannabinoid receptor 2 (Cnr2) promoter. Kidney injury was established in a genetic mouse model expressing green fluorescent protein (GFP) driven by the endogenous Cnr2 promoter. Kidney injury was initiated by either treatment with different chemicals [cisplatin or lipopolysaccharide (LPS)] or by unilateral ureteral obstruction (UUO). Changes in the detection of GFP were used as a proxy for CB2 levels and localization. Histological changes due to the injury stimuli were observed by time-related, morphological changes in kidney cytoarchitecture and blood parameters, such as serum creatinine levels. Cnr2 mRNA levels were detected by reverse transcription coupled to polymerase chain reaction (RT-PCR) while protein changes in the tissue lysates were measured by Western blot analysis. Cellular localization of GFP was detected by fluorescent microscopy. Our data demonstrated that there was no band or a minimally detectable band for GFP using kidney lysates from vehicle- or cisplatin-treated mice. A similar lack of GFP was detected in the UUO kidney versus the contralateral control kidney. This is consistent with the low, albeit detectable levels of Cnr2 mRNA in the kidney samples from control or cisplatin treatment. In frozen kidney sections from vehicle and cisplatin-treated mice, GFP fluorescence was not detectable in tubular epithelia, glomeruli or blood vessels in the cortex. Instead, GFP was detected in rare cells within the interstitial space. A second chemical injury model using LPS found a similar lack of GFP protein levels and an absence of legitimate GFP fluorescence in the main cell types within the kidney. These findings suggest that Cnr2 promoter activity is minimally active in normal or injured kidneys, and that pharmacological manipulation of CB2 receptors may be associated with receptors being expressed in cells recruited to the kidney.
尽管已知2型大麻素（CB2）受体活性可促进肾脏中的多种生物学功能，但有关CB2受体蛋白水平及其在肾脏内细胞分布的已发表数据并不一致。本研究的目的是使用由内源性大麻素受体2（Cnr2）启动子驱动的绿色荧光蛋白（GFP）表达基因小鼠模型，研究暴露于各种形式肾损伤的小鼠肾脏中CB2的变化。通过用内源性Cnr2启动子驱动绿色荧光蛋白（GFP）表达的基因小鼠模型建立肾损伤。肾损伤通过用不同化学物质[顺铂或脂多糖（LPS）]处理或通过单侧输尿管梗阻（UUO）引发。GFP检测的变化用作CB2水平和定位的替代指标。通过与时间相关的肾脏细胞结构形态变化和血液参数（如血清肌酐水平）观察损伤刺激引起的组织学变化。通过逆转录聚合酶链反应（RT-PCR）检测Cnr2 mRNA水平，同时通过蛋白质印迹分析测量组织裂解物中的蛋白质变化。通过荧光显微镜检测GFP的细胞定位。我们的数据表明，使用来自溶剂或顺铂处理小鼠的肾脏裂解物，未检测到GFP条带或仅检测到最低限度的条带。与对侧对照肾脏相比，在UUO肾脏中也检测到类似的GFP缺失。这与对照或顺铂处理的肾脏样品中Cnr2 mRNA水平低但可检测到一致。在来自溶剂和顺铂处理小鼠的冷冻肾脏切片中，在皮质的肾小管上皮、肾小球或血管中未检测到GFP荧光。相反，在间质空间中的罕见细胞中检测到GFP。使用LPS的第二种化学损伤模型发现肾脏主要细胞类型中类似的GFP蛋白水平缺失和缺乏正常的GFP荧光。这些发现表明，Cnr2启动子活性在正常或受损肾脏中最低限度地活跃，并且CB2受体的药理学操作可能与在募集到肾脏的细胞中表达的受体相关。
