Biochemical characteristics of human renin expressed in transgenic mice

1. Biochemical properties of human renin expressed in transgenic mice (hRN8-12 mice) carrying the human renin gene (Fukamizu et al. Biochem Biophys Res Commun 1989; 165: 826–32) were examined. The optimum pH of the enzymic activity against human angiotensinogen was 5.5 for both plasma and renal human renin in the hRN8-12 mice. Plasma concentrations of human active and inactive renin in the plasma of hRN8-12 mice were 16.7 ± 2.8 and 79.9 ± 14.0 pmol of angiotensin 1 h−1 ml−1, respectively, thereby indicating that the predominant form of plasma human renin is the inactive form, as is the case in humans. 2. The molecular masses of plasma human active and inactive renin and renal human active renin in the hRN8-12 mice were estimated to be 46kDa, 48kDa and 44kDa, respectively, as determined by h.p.l.c. on G3,000SW. 3. Human renin in the hRN8-12 mouse kidney was bound to a concanavalin A-Sepharose column, and was eluted with α-methyl-d-mannoside, showing that this renin is glycosylated, as is native human renin. 4. Low sodium treatment of the hRN8-12 mice for 2 weeks increased plasma human active renin, renal human renin and renal human renin mRNA levels by 2.6-, 3.8- and 2.8-fold, respectively. Thus, the biosynthesis and secretion of renal human renin in these transgenic mice are obviously stimulated by sodium depletion.

Download Full-text

Stimulation of plasma inactive renin by dexamethasone in the cat

AJP Endocrinology and Metabolism ◽

10.1152/ajpendo.1989.257.6.e879 ◽

1989 ◽

Vol 257 (6) ◽

pp. E879-E884

Author(s):

N. Glorioso ◽

C. Troffa ◽

G. Tonolo ◽

M. G. Melis ◽

P. Manunta ◽

...

Keyword(s):

Time Course ◽

Consensus Sequence ◽

Recovery Period ◽

Base Line ◽

Active Renin ◽

Human Renin ◽

Inactive Form ◽

Inactive Renin ◽

Selective Increase ◽

Stimulation Of

An inactive form of renin in human plasma is the biosynthetic precursor, prorenin. The cat is a good animal model for studies of inactive renin. The gene for human renin contains sequences homologous to the glucocorticoid consensus sequence. The response of cat plasma (active and inactive renin) and of angiotensinogen to administration of dexamethasone (0.5 mg/kg im, daily) was studied in ketamine-sedated cats (20 mg/kg im). Inactive renin increased by twofold after 7 days of dexamethasone (P less than 0.01). After a 7-day recovery period, it returned to base line. Active renin did not change. Angiotensinogen fell by 35% (P less than 0.01). The time course of the selective increase of plasma inactive renin showed that inactive renin began to rise after 2 days, peaking after 5 days. Ketamine alone induced inactive renin to rise slightly but significantly (P less than 0.05), although the magnitude of the increment was much less than that observed in ketamine-sedated cats receiving dexamethasone (P less than 0.01). Active renin did not change, whereas angiotensinogen was reduced by 25% (P less than 0.01). Our findings support the hypothesis that glucocorticoids might have a selective role in the synthesis and/or secretion of the precursor of renin, at least in the cat.

Download Full-text

Two-Site Direct Immunoassay Specific for Active Renin

Clinical Chemistry ◽

10.1093/clinchem/38.10.1959 ◽

1992 ◽

Vol 38 (10) ◽

pp. 1959-1962 ◽

Cited By ~ 44

Author(s):

D Simon ◽

D J Hartmann ◽

G Badouaille ◽

G Caillot ◽

T T Guyenne ◽

...

Keyword(s):

Magnetic Beads ◽

Active Form ◽

Plasma Renin ◽

Active Plasma ◽

Immunoradiometric Assay ◽

Active Renin ◽

Human Renin ◽

Direct Immunoassay ◽

Inactive Renin ◽

Normotensive Subjects

Abstract A sensitive immunoradiometric assay, without an enzymatic step and specific for active human renin, was developed with use of two monoclonal antibodies (MAbs). In this assay system, the first MAb was coupled to magnetic beads (Magnogel); the second one, directed against the active form of the enzyme, was radiolabeled with 125I. The specificity of this assay was demonstrated in experiments measuring the active plasma renin concentration in the presence or absence of inactive renin. The assay, performed in two steps, was sensitive enough to detect 0.9 pg of renin per tube (3.5 ng/L). Intra- or interassay CVs were < 10%. Concentrations of active plasma renin measured in normotensive subjects were between 7 and 40 ng/L.

Download Full-text

Effect of prostaglandin inhibition by indomethacin on plasma active and inactive renin concentration in men

Canadian Journal of Physiology and Pharmacology ◽

10.1139/y91-200 ◽

1991 ◽

Vol 69 (9) ◽

pp. 1355-1359 ◽

Cited By ~ 2

Author(s):

P. Lijnen ◽

J. Staessen ◽

R. Fagard ◽

A. Amery

Keyword(s):

Plasma Concentrations ◽

Work Load ◽

Prostaglandin E ◽

Active Renin ◽

Prostaglandin F ◽

Inhibition Of Prostaglandin Synthesis ◽

Inactive Renin ◽

Exercise Induced ◽

Total P ◽

Rest And Exercise

The effect of inhibition of prostaglandin synthesis by indomethacin on active renin and on acid-activable inactive renin was studied in nine healthy, sodium-replete men, both at rest and exercise. These volunteers were investigated after pretreatment with placebo or indomethacin, 150 mg daily for 3 days. Indomethacin induced a decrease in active (p = 0.004), total (p < 0.001), and inactive (p = 0.02) renin at rest recumbent on average by 42, 19, and 8%, respectively, and at rest sitting on average by 45, 15, and 3%, respectively. Inhibition of prostaglandins with indomethacin reduced (p < 0.001) active and total renin at each level of work load but not (p = 0.32) inactive renin. However, the exercise-induced stimulation (p < 0.05) of active and total renin still occur during indomethacin. Indomethacin reduced (p < 0.001) at rest sitting and at maximal exercise the plasma concentrations of immunoreactive prostaglandins E2 by 50 and 54%, respectively, prostaglandin F2α by 36 and 39%, respectively, and 13,14-dihydro-15-keto-prostaglandin Fα by 38 and 60%, respectively. The urinary excretion of immunoreactive prostaglandin E2 and F2α was also reduced.Key words: indomethacin, prorenin, active renin, prostaglandins.

Download Full-text

Human Renin mRNA Expression and Renin Activity in Transgenic Mice.

Hypertension Research ◽

10.1291/hypres.23.385 ◽

2000 ◽

Vol 23 (4) ◽

pp. 385-389 ◽

Cited By ~ 1

Author(s):

Liqun JIANG ◽

Lan-Ying CHEN

Keyword(s):

Transgenic Mice ◽

Mrna Expression ◽

Renin Activity ◽

Human Renin ◽

Renin Mrna

Download Full-text

Active renin, prorenin, and renin gene expression after reduced renal perfusion pressure in term ovine fetuses

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1998.275.1.r141 ◽

1998 ◽

Vol 275 (1) ◽

pp. R141-R147 ◽

Cited By ~ 4

Author(s):

Jon S. Rosnes ◽

Nancy Valego ◽

Jinjuan Wang ◽

Timothy Zehnder ◽

James C. Rose

Keyword(s):

Perfusion Pressure ◽

Renal Perfusion ◽

Mrna Levels ◽

Renal Perfusion Pressure ◽

Active Renin ◽

Renin Gene ◽

Plasma Active Renin ◽

Renin Mrna ◽

Ovine Fetus ◽

Near Term

We studied the pattern of plasma active renin concentration (ARC), prorenin concentration (PRC), renal renin concentration, and the renin mRNA levels in ovine fetuses subjected for 24 h to reduced renal perfusion pressure (RPP). The results obtained in five animals (133.8 ± 1.4 days of gestation) in which RPP was reduced by 10 mmHg were compared with those in seven control fetuses (130.3 ± 0.8 days of gestation) without pressure reduction. Plasma samples were obtained before and at intervals of 24 h after initiating reduced RPP. The plasma ARC increased within 60 min of reduced RPP, reaching a maximum (13.0 ± 4.7 vs. 115.7 ± 23.8, P < 0.01) at 3 h. The ARC then declined toward control values. In contrast, plasma PRC did not increase consistently until 4 h into reduced RPP, with maximal levels at 24 h (8.2 ± 2.4 vs. 87.7 ± 21.9, P = 0.016). Within the kidney PRC, but not ARC, increased significantly, by 2.5-fold. Reduced RPP also increased renal renin mRNA levels ( P = 0.004). We conclude that a chronic reduction in RPP in the near-term ovine fetus increases renal PRC and is associated with increased plasma prorenin levels. The data suggest that the conversion of prorenin to active renin is an important regulation point of the renin ANG system during development.

Download Full-text

Glial-specific ablation of angiotensinogen lowers arterial pressure in renin and angiotensinogen transgenic mice

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.00435.2005 ◽

2005 ◽

Vol 289 (6) ◽

pp. R1763-R1769 ◽

Cited By ~ 22

Author(s):

Mikhiela Sherrod ◽

Deborah R. Davis ◽

Xizhou Zhou ◽

Martin D. Cassell ◽

Curt D. Sigmund

Keyword(s):

Arterial Pressure ◽

Transgenic Mice ◽

Glial Cells ◽

Systemic Circulation ◽

Cre Recombinase ◽

Mrna Levels ◽

Ang Ii ◽

Human Renin ◽

Liver And Kidney ◽

The Brain

Angiotensinogen (AGT) is mainly expressed in glial cells in close proximity to renin-expressing neurons in the brain. We previously reported that glial-specific overexpression of ANG II results in mild hypertension. Here, we tested the hypothesis that glial-derived AGT plays an important role in blood pressure regulation in hypertensive mice carrying human renin (hREN) and human AGT transgenes under the control of their own endogenous promoters. To perform a glial-specific deletion of AGT, we used an AGT transgene containing loxP sites (hAGTflox), so the gene can be permanently ablated in the presence of cre-recombinase expression, driven by the glial fibrillary acidic protein (GFAP) promoter. Triple transgenic mice (RAC) containing a: 1) systemically expressed hREN transgene, 2) systemically expressed hAGTflox transgene, and 3) GFAP-cre-recombinase were generated and compared with double transgenic mice (RA) lacking cre-recombinase. Liver and kidney hAGT mRNA levels were unaltered in RAC and RA mice, as was the level of hAGT in the systemic circulation, consistent with the absence of cre-recombinase expression in those tissues. Whereas hAGT mRNA was present in the brain of RA mice (lacking cre-recombinase), it was absent from the brain of RAC mice expressing cre-recombinase, confirming brain-specific elimination of AGT. Immunohistochemistry revealed a loss of AGT immunostaining glial cells throughout the brain in RAC mice. Arterial pressure measured by radiotelemetry was significantly lower in RAC than RA mice and unchanged from nontransgenic control mice. These data suggest that there is a major contribution of glial-AGT to the hypertensive state in mice carrying systemically expressed hREN and hAGT genes and confirm the importance of a glial source of ANG II substrate in the brain.

Download Full-text

Developmental changes in renin gene expression in ovine kidney cortex

AJP Regulatory Integrative and Comparative Physiology ◽

10.1152/ajpregu.1993.264.3.r591 ◽

1993 ◽

Vol 264 (3) ◽

pp. R591-R596 ◽

Cited By ~ 9

Author(s):

G. M. Carbone ◽

A. U. Sheikh ◽

S. Rogers ◽

G. Brewer ◽

J. C. Rose

Keyword(s):

Late Gestation ◽

Kidney Cortex ◽

Transcriptional Level ◽

Mrna Levels ◽

Strongly Correlated ◽

Developmentally Regulated ◽

Active Renin ◽

Renin Gene ◽

Renin Mrna ◽

Renin Content

The ontogeny of renin mRNA and renin content from renal cortical slices was studied in two groups of ovine fetuses at 92-94 days (0.64 gestation) and at 138-142 days (0.96 gestation), newborn lambs (0.4-2 days old), and adult sheep. Renal renin mRNA was identified by hybridization with a 32P-labeled full length rat renin cDNA. Renal renin content was measured as nanograms of angiotensin I generated per hour (active renin). There was a significant age effect on renin mRNA levels (F = 10.0, P < 0.001); values increase significantly between 0.64 and 0.95 g (P < 0.005), remain elevated in the newborns (P < 0.05), and subsequently decline in adulthood (P < 0.005). Likewise, renal renin content was significantly higher in late gestation fetuses and newborn lambs than in early gestation and adults (F = 8.3, P < 0.003). The renal renin content was strongly correlated with renin mRNA levels (R = 0.88, P < 0.0001). These results suggest that 1) the renin gene is developmentally regulated in the ovine kidney and 2) the renal content of active renin in basal conditions is regulated, at least in part, by events at the transcriptional level.

Download Full-text

Potential effects of renin activation on the regulation of renin production

AJP Renal Physiology ◽

10.1152/ajprenal.1984.247.2.f205 ◽

1984 ◽

Vol 247 (2) ◽

pp. F205-F212 ◽

Cited By ~ 2

Author(s):

W. A. Hsueh

Keyword(s):

Cdna Probe ◽

Human Kidney ◽

Adrenergic System ◽

Diabetic Patients ◽

Beta Adrenergic ◽

Active Renin ◽

Human Renin ◽

Release Studies ◽

Normal Humans ◽

Inactive Renin

In normal humans nearly half the renin in plasma and kidney is inactive. Human inactive renin can be activated by a variety of proteases and by exposure to low pH and is a putative biosynthetic precursor of renin, i.e., prorenin. Pulse-labeling studies in a human renin-secreting tumor suggest that renin is synthesized as a prepro- and proform, both of which are inactive. Using the cDNA probe to deduce the amino acid sequence of precursor renin from the nucleotide sequence of human kidney mRNA, the prosegment was estimated to be 46 amino acids long, similar to differences in molecular weight between active and inactive renin. In plasma of diabetic patients with nephropathy and the syndrome of hyporeninemic hypoaldosteronism, inactive renin levels are increased 3-5 times normal. The inability to activate renin in this syndrome strongly implies that conversion of inactive (pro-) renin to active renin may be physiologically relevant to active renin production. Furthermore, in normal humans profound stimulation of active renin can be accompanied by a reciprocal drop in circulating inactive renin levels. The beta-adrenergic system and prostaglandins are two major, but independent, mechanisms of stimulating renin release. Studies in our laboratory suggest that prostaglandins and the beta-adrenergic system may act at different sites in renin production: beta-stimulation may act at early steps in renin biosynthesis, while prostaglandins may act preferentially at later steps that possibly involve conversion of inactive to active renin. Proof of this hypothesis lies in purification of inactive renin to determine whether it is prorenin and in the use of the renin cDNA probe to study pre- vs. posttranslational events in renin processing.(ABSTRACT TRUNCATED AT 250 WORDS)

Download Full-text

Inactive Renin in Rabbit Plasma: Effect of Frusemide

Clinical Science ◽

10.1042/cs0600393 ◽

1981 ◽

Vol 60 (4) ◽

pp. 393-398 ◽

Cited By ~ 9

Author(s):

H. K. Richards ◽

D. J. Lush ◽

A. R. Noble ◽

K. A. Munday

Keyword(s):

Plasma Levels ◽

Time Course ◽

Rabbit Plasma ◽

Active Renin ◽

Inactive Form ◽

Plasma Active Renin ◽

Inactive Renin ◽

Time Courses ◽

Induced Changes ◽

Sodium And Potassium

1. An inactive form of renin exists in rabbit plasma. This can be activated, and therefore measured, after acidification (pH 2.8). 2. The effect of frusemide diuresis, with replacement of volume losses, on plasma levels of active and inactive renin was studied over a 3 1/2 h time course. Plasma active renin increased during frusemide diuresis but inactive renin disappeared from the circulation. The time courses for the changes in the two forms of renin were similar. 3. The peak of the frusemide-induced changes in renal function (urine flow, sodium and potassium excretion and creatinine clearance) preceded the maximum changes in the two forms of renin by 90 min. 4. The response of plasma levels of inactive renin to physiological stimuli depends on the nature of the stimulus, as well as its duration. Some form of sodium-sensitive mechanism may control the activation of inactive renin.

Download Full-text