ReninSense on the ASK
Renin is a peptide hormone secreted by the kidney from granular cells of the juxtaglomerular apparatus. This secretion is the first step in a cascade of events that leads to increased blood pressure. Renin is upregulated in response to sympathetic nervous system activity, a decrease in arterial blood pressure, or a decrease in plasma sodium chloride levels. Specifically, renin upregulation leads to increased blood pressure by cleaving angiotensinogen (produced in the liver) to yield angiotensin I, which is further converted to angiotensin II. Angiotensin II constricts blood vessels, increases aldosterone secretion from the adrenals, and stimulates a thirst reflex.
ReninSense™ 680 FAST is a renin activatable agent that is optically silent upon injection and produces fluorescent signal after cleavage by renin produced in the kidneys. The Renin-Angiotensin System (RAS) is the hormone system involved in regulating blood pressure and fluid balance in the body. ReninSense 680 FAST may be used to monitor abnormal RAS function, progression of disease, and the efficacy of therapeutic treatment in disorders such as hypertension and cardiovascular disease and some neurological diseases. Specifically, ReninSense 680 FAST is recognized and activated by rodent forms of renin in preclinical animal models.
ReninSense 680 FAST is a member of a family of the activatable fluorescent imaging agents comprising a novel architecture, termed F.A.S.T. (Fluorescent Activatable Sensor Technology). These agents confer an improved pharmacokinetic profile with a broader range of early imaging time points. This architecture also offers higher target specific signal with reduced background.
Figure 1: Description and mechanism of ReninSense 680 FAST
Figure 2: ReninSense 680 FAST was tested in vitro for cleavage activity by species specific renin. Species-specific substrate sequences (hRS680, rRS680) were derived from angiotensinogen. These substrates were highly specific for cleavage by their respective renin. As shown in the left panel, ReninSense 680 FAST is a highly specific substrate for rodent renin.
Products and catalog numbers
|Product||Catalog Number||Ex/Em wavelength (nm)||Molecular weight (g/mol)||Validated Experiments||Applications|
|ReninSense 680 FAST||NEV11079||675/693||43,000||In vivo/Ex vivo|
In vitro microscopy
Using ReninSense 680 FAST in vivo/ex vivo
The recommended procedure for in vivo imaging with ReninSense 680 FAST is administration via intravenous injection and imaging 24 hours post injection. Earlier and later time points may be appropriate for some disease models, and the optimal imaging time point for any application should be determined empirically.
|Product||Route of Injection||Mouse Dose (25 g)||Rat Dose (250 g)||Blood t 1/2||Tissue t 1/2||Optimal imaging time||Optimal Re-injection Time (complete clearance)||Route of Metabolism/ background tissue||FMT and IVIS settings|
|ReninSense 680 FAST||IV||2 nmol||6-20 nmol||7 h||48 h
||24 (12-24) h
||4 d||Kidney, lung, liver||FMT 680/700
Figure 3A: Induction of Renin Activity in Mice. Mice were fed a low salt diet with amiloride (LSD/A) or normal diet to induce upregulation of renin activity (left panel). Upregulation is confirmed by detecting high renin activity in plasma (right panel).
Figure 3B: Non-invasive imaging of kidneys from mice treated as shown in Figure 3A. Using FMT 2500 and ReninSense 680 FAST, upregulation of renin can be detected in LSD/A-induced mice (left panel). This was confirmed by ex vivo assessment of the tissue (right panel).
Figure 4: Renin imaging with ReninSense 680 was validated using a selective renin inhibitor (L-810). As shown in the above panels, ReninSense 680 FAST signal was reduced in the presence of the renin inhibitor.
Ex Vivo Imaging
Figure 5: Ex vivo validation of ReninSense 680 selectivity. ReninSense 680 detects increased renin activity in tissue and plasma samples from mice fed on a low salt diet (LSD) and is selectivity inhibited by the renin inhibitor, L-810.
Frozen Tissue Protocol
We have validated ReninSense 680 FAST for use with frozen tissue samples (kidney tissue). Here is a brief protocol with a recommended concentration of agent to use:
- Freeze tissue (without agent) and section 5-10 µm by cryostat. To increase kidney renin activity, C57BL/6 can be placed on a low salt diet for 2-3 days prior to harvest of kidneys.
- Incubate with 1 uM ReninSense 680 FAST at 37 ºC for 3 hours.
- Wash 1x with PBS.
- Mount with anti-fade reagent.
- Fluorescence microscopy filter: Cy5.5
Q. Can I use ReninSense 680 FAST in humans?
A. No, ReninSense 680 FAST is intended for animal research only and not for use in humans.
Q. Where do I draw the blood and can the blood samples be stored and read at a later date?
A. The blood can be drawn however you are comfortable. Our experts do not recommend storing the samples because it can affect the fluorescent signal.
Please visit our Citations Library for references using ReninSense 680 FAST on the IVIS or on the FMT.