Which Of The Following Physiologic Effects Is Most Likely To Be Observed In These Animals Nbme 13
NEW & NOTEWORTHY
This report provides new mechanistic insight into the impact of suppressor of cytokine signaling 3 (SOCS3) on the vasculature, including divergent furnishings depending on the source of angiotensin II (Ang Two) (local vs. systemic). Bone marrow-derived cells deficient in SOCS3 protect confronting systemic Ang II-induced vascular dysfunction.
carotid artery disease contributes to stroke and cognitive deficits. Angiotensin Ii (Ang II) is a major effector of the renin-angiotensin system, known to play diverse roles in diverse forms of vascular illness and hypertension, including carotid artery affliction (21, 42). Clinical and experimental studies indicate that Ang 2, via activation of the AT1 receptor (AT1-R), impairs vascular function, contributing to progression of vascular affliction (42). Ii major interrelated effects of Ang II are oxidative stress and inflammation (8). Ang Ii increases vascular oxidative stress via mechanisms that include activation of NADPH oxidases, a major source of superoxide (22, 29, 45). Superoxide impairs endothelial office through interactions with endothelium-derived nitric oxide (NO) and other mechanisms. Endothelial dysfunction is a key result in the onset and pathogenesis of vascular diseases of diverse etiology (55). Genetic or pharmacological interventions that inhibit formation or furnishings of reactive oxygen species (ROS) protect against Ang Two-induced endothelial dysfunction and hypertension (27, 34).
Low-grade inflammation is a common feature of vascular illness. For example, activation of NF-κB, a fundamental integrator of inflammatory molecule expression, occurs in response to Ang Two (25). Ang II-induced oxidative stress, endothelial dysfunction, and hypertension crave expression of IL-6 and activation of JAK/STAT3 (28, 51). A negative regulator of IL-half-dozen/JAK/STAT3 signaling is suppressor of cytokine signaling iii (SOCS3), which suppresses this signaling pathway by multiple mechanisms (58). Although a role for SOCS3 in the immune system and cancer is known, the functional importance of SOCS3 in vascular illness and hypertension has not been defined.
Considering both circulating and local (tissue) sources of Ang 2 are well described (30), we used models that tested both effects of Ang II on the vasculature. We examined the hypothesis that SOCS3 protects confronting Ang Two-induced vascular dysfunction and divers mechanisms involved. For most experiments, nosotros studied carotid arteries, a segment of the apportionment where the clinical consequences of vascular affliction commonly emerge. As part of our attempt, we also examined a resistance artery. Overall, the findings obtained support the concept that SOCS3 has functionally important effects in both Ang II-induced vascular dysfunction and hypertension.
METHODS
Experimental animals.
We used a model with fractional genetic deficiency in Socs3 (SOCS3+/−). SOCS3-deficient mice were generated previously by deleting the exon containing the unabridged coding region of the gene (36). Whereas consummate genetic deficiency in SOCS3 is lethal, SOCS3+/− mice are phenotypically normal under unstressed conditions (36). We obtained breeding pairs of these mice from Dr. Paul Rothman. Animals for study were obtained past breeding SOCS3+/− with C57BL6/J mice. Both male and female SOCS3+/− mice and SOCS3+/+ littermates (wild-type, WT) (∼4–6 mo of age) were used. A modest series of studies were also performed in male C57BL6/J mice. Mice were fed regular chow and h2o and maintained under standard housing weather condition. All studies followed the Guide for the Care and Use of Laboratory Animals and were approved past the Institutional Animal Care and Use Committee at the Academy of Iowa.
Straight furnishings of Ang Ii on the vasculature.
Mice were euthanized with pentobarbital (100 mg/kg ip). Carotid arteries and aorta were removed, cleaned, cutting into segments ∼v mm in length, and placed in oxygenated Krebs solution containing 118.iii mM NaCl, 4.7 mM KCl, 2.5 mM CaCl2, 1.2 mM MgSOiv, one.2 mM KHtwoPO4, 25.0 mM NaHCO3, and eleven.0 mM glucose. As described previously (eleven, 12, 28, 51), vessels were and then incubated for 22 h in DMEM growth medium (containing 5 mM glucose, 120 U/ml penicillin, 120 μg/ml streptomycin, and 50 μg/ml polymixin B at 37°C, gassed with 95% Oii-5% CO2) with vehicle (DMSO or saline) or Ang II (1 or ten nM) or a combination of Ang II with S3I-201 (10 μM), or losartan (1 μM), or NF-κB essential modulator (NEMO)-binding domain (NBD) peptides (10 μM), or an anti-IL-6 antibody (5 μg/ml).
Post-obit incubation, arteries were suspended in organ baths (xx). To evaluate endothelial part, responses to cumulative addition of acetylcholine (10−10-10−4 M) were measured following precontraction (∼50–60% of maximum) using the thromboxane A2 analog U46619. We establish previously that vasodilation to acetylcholine is mediated past endothelial NO synthase (eNOS) in this artery (20). Nitroprusside (x−ten-x−4 Thousand) was used to assess endothelium-independent relaxation (twenty). Tempol (1 mM), a superoxide scavenger, was used to determine whether vascular dysfunction was mediated past superoxide.
Ang Ii-dependent hypertension.
Following anesthesia with ketamine/xylazine (87.v and 12.5 mg/kg ip, respectively), osmotic minipumps (model 1002, Alzet) were implanted subcutaneously to deliver saline or a pressor dose of homo Ang Two (Sigma-Aldrich, 1.4 mg/kg per day) for fourteen days (28). In a subset of animals, a nonpressor dose of Ang Two was used (0.28 mg/kg per 24-hour interval).
For studies of a resistance vessel, basilar arteries were isolated, cannulated, and pressurized to 60 mmHg, so lumen diameter could be measured as described (18, 19, 28). To examine dilator responses, arteries were starting time constricted by ∼30% using U46619.
Blood pressure measurements.
Systolic blood pressure was measured in conscious mice as performed previously (ane, 12, 13, 28, 48). Mice were trained for v days before pump implantation, and blood force per unit area was measured daily in the morning later on pump implantation. Using this approach, nosotros have establish a practiced correlation between measurement of arterial pressure with tail cuff and straight measurements with indwelling catheters in awake mice (13, 47, 48).
Os marrow chimeric mice.
CD45.i mice, a C57BL/6J congenic strain used wildly in transplant studies (54), were obtained from the National Cancer Institute. This strain carries the differential pan leukocyte marker CD45.1, whereas WT C57BL/6 express CD45.2. CD45.1 and CD45.ii mice are phenotypically identical (41) but are different genetically at the single locus of the ptprc gene, which encodes an antigen constitute in all leukocytes (56). As described (26), the contributions of CD45.1 and CD45.2 to hematopoiesis were detected using plasma samples and flow cytometry afterwards staining with their specific antibodies, respectively.
As described (26), WT (WT CD45.1), SOCS3+/−, and SOCS3+/+ mice were irradiated with two doses (500 and 450 rad) of whole trunk X-ray irradiation. To isolate bone marrow from donors, femur, hips/pelvis, and tibia were removed and stored in sterile RP10 media (Gibco) supplemented with 10% fetal calf serum, 100 U of penicillin, 100 μg of streptomycin, and 50 μg of gentamicin per ml, ten mM HEPES, two mM l-glutamine, and 50 μM 2-mercaptoethanol until bone marrow removal. After removal of bone tips, bone marrow was flushed out using a needle and syringe. Isolated bone marrow was then spun down, and red blood cells were lysed for 30 s followed by multiple washings. Irradiated recipient mice were reconstituted with five million full cells per mouse via tail vein injection. Os marrow chimeras were provided with drinking HiiO containing ampicillin (2 mg/ml) for 6 wk and were housed for a minimum of 8 wk to allow reconstitution of the peripheral allowed system.
Fluorescence-activated jail cell sorting.
Peripheral blood samples were nerveless from the retroorbital vein. Later depletion of RBCs with the use of ACK lysis buffer (dd HtwoO containing 0.15 K of NHfourCl, ane.00 mM of KHCOthree, and 0.x mM of Na2EDTA), cells were resuspended in fluorescence-activated cell sorting (FACS) buffer (PBS containing iii% fetal calf serum) and incubated with an antibody mixture (anti-mouse CD16/32 for preventing nonspecific Ab binding, anti-mouse CD45.1, and anti-mouse CD45.2) for 30 min in a 96-well flat-bottom plate. After being washed with FACS buffer twice, cells were fixed with Cytofix/Cytoperm (BD Biosciences). Cells were analyzed by menstruum cytometry (BD Biosciences), and nerveless data were analyzed using FlowJo (TreeStar).
Quantitative real-time RT-PCR.
RNA from aorta, isolated from the same mice in which carotid or cerebral arteries were used for functional studies, was prepared using the RNAeasy (Qiagen) method following extraction with TRIzol reagent (Invitrogen) (6, 28). RNA concentrations were determined using a NanoDrop spectrophotometer, with an OD260/OD280 ratio of greater than 1.nine (indicating very loftier-quality RNA) (6, 28). Identical amounts of RNA (300 ng) were used for RT. Identical amounts of RT product were used for existent-time PCR with a single well of a 96-well plate containing both TaqMan probes/primers (Applied Biosystems) for genes of interest (with FAM fluorophore) and β-actin (with VIC fluorophore) equally a housekeeping gene. Expression levels were normalized to β-actin. Expression of eNOS (Mm00435204_m1, Life Technologies) and AT1a receptors for Ang 2 (ATi-R, Mm01166161_m1, Life Technologies), superoxide dismutase one (SOD1) (Mm01344233_g1, Life Technologies), SOD2 (Mm01313000_m1, Life Technologies), SOCS1 (Mm06782550_s1, Life Technologies), SOCS3 (Mm01249143_g1, Life Technologies), and IL-6 (Mm 00446190_m1, Life Technologies) were determined past quantitative real-time RT-PCR using the TaqMan method.
Drugs.
Acetylcholine, nitroprusside, losartan, and tempol were obtained from Sigma-Aldrich. U46619 (Cayman Chemical) was dissolved in ethanol with subsequent dilutions made in saline. Other chemicals were S3I-201 (Calbiochem), NBD peptides (Imgenex), and an anti-IL-6 antibiotic (R&D Systems).
Statistical analysis.
All information are expressed every bit means ± SE. Relaxation responses are presented as percent of relaxation relative to the level of precontraction induced by U46619. Absolute contractions were presented equally grams of tension. In cerebral arteries, changes in vessel bore were expressed as percentage of change. Results were expressed equally the means ± SE and compared by Student's t-examination or ANOVA followed by Educatee-Newman-Keuls post hoc exam as appropriate. Differences were considered significant at P ≤ 0.05.
RESULTS
Partial SOCS3 deficiency augments direct furnishings of Ang Two on endothelial function.
Acetylcholine produced concentration-dependent relaxation in carotid arteries from C57BL6/J mice incubated with vehicle (Fig. 1). Ang Ii (10 nM) reduced the maximal response past approximately half, and these inhibitory effects were prevented past losartan, an AT1-R antagonist (Fig. 1). Responses to nitroprusside were not affected past Ang Ii or losartan (Fig. 1).
Levels of SOCS3 mRNA in the vasculature were reduced past ∼50% in SOCS3+/− mice (compared with WT SOCS3+/+) either when vessels were simply harvested or in mice that were infused with vehicle for 2 wk (Fig. twoA). In dissimilarity, mRNA levels for SOCS1 were not altered in SOCS3+/− mice (Fig. iiA). These results confirm fractional genetic deficiency of SOCS3 and suggest that there was no compensatory increase in expression of a closely related SOCS isoform.
Because nosotros hypothesized that directly effects of Ang II would be enhanced in SOCS3+/− mice, we tested effects of a lower concentration of Ang Ii (one nM) in subsequent experiments. In arteries from SOCS3+/+ and SOCS3+/− mice, relaxation to acetylcholine was similar afterwards incubation with vehicle. Consistent with previous findings, this low concentration of Ang II did not touch on acetylcholine-induced responses in arteries from WT mice (Fig. 2B) (12). In dissimilarity, one nM Ang Two reduced responses in arteries from SOCS3+/− mice by ∼50% (Fig. 2B). Vascular responses to nitroprusside (Fig. 3) and U46619 (data not shown) were like in these groups, indicating that furnishings of Ang II were selective for endothelial cells. These information suggested that partial deficiency in SOCS3 does non alter vascular function under baseline atmospheric condition but predisposes to Ang Two-induced endothelial dysfunction.
Endothelial dysfunction in SOCS3+/− mice requires oxidative- and inflammatory-related signaling.
To exam whether Ang II-induced endothelial dysfunction in SOCS3+/− mice was mediated past superoxide, responses were examined in the presence of tempol. Ang II-induced harm of responses to acetylcholine in arteries from SOCS3+/− mice was reversed by tempol (Fig. 4A), whereas relaxation in arteries treated with vehicle was non afflicted (Fig. 4A). In addition, nitroprusside-induced vasodilation was similar in these groups (Fig. 5A).
To test whether Ang II-induced endothelial dysfunction in SOCS3+/− mice is dependent on activation of NF-κB, a cell-penetrating NBD peptide was used. This NBD peptide inhibits NF-κB activation in models of inflammation (39). Acetylcholine-induced relaxation was similar in WT arteries treated with vehicle or Ang II, equally well as vehicle-treated SOCS3+/− arteries (Fig. fourB). NBD peptide did not alter endothelial function in WT mice or vehicle-treated SOCS3+/− mice (Fig. ivB) but prevented Ang II-induced endothelial dysfunction in SOCS3+/− mice (Fig. 4B). The inactive control peptide had no issue on acetylcholine-induced relaxation (Fig. 4B). Nitroprusside-induced vasodilation was also like in these groups (Fig. vB).
To determine whether furnishings of Ang II were mediated by IL-6 and/or STAT3, arteries were incubated with an anti-IL-6 antibody or a STAT3 inhibitor (S3I-201). Ang Ii-induced endothelial dysfunction in SOCS3+/− mice was prevented by these inhibitors (Fig. 4, C and D). Neither the antibody nor S3I-201 altered acetylcholine-induced relaxation in arteries from WT mice or vessels from SOCS3+/− mice treated with vehicle (Fig. iv, C and D). Vascular responses to nitroprusside were similar in these groups (Fig. 5, C and D).
SOCS3 deficiency protects against endothelial dysfunction in Ang II-dependent hypertension.
To examine the impact of SOCS3 in vivo, we produced hypertension by infusing a pressor dose of Ang II chronically. Ang Two infusion reduced the response to acetylcholine in arteries from SOCS3+/+ mice past more than than 50%, an effect that was largely prevented by tempol (Fig. 6A), and was similar in magnitude to that seen in the incubation model (Fig. i). Unexpectedly, Ang 2 had trivial consequence on endothelial function in SOCS3+/− mice (Fig. 6A). Relaxation of arteries to acetylcholine was like in saline-treated groups with or without tempol (Fig. half dozenA). Responses to nitroprusside and U46619 were similar in these groups also (Fig. 7, A and B).
Protective furnishings of SOCS3 deficiency extend to resistance arteries.
To examine the functional importance of SOCS3 in a resistance vessel, basilar arteries were isolated from saline- and Ang Ii-infused mice. Dilation of basilar arteries from SOCS3+/+ mice to acetylcholine was reduced by approximately ane-half in the Ang II-treated grouping compared with mice treated with saline (Fig. 6B). Consistent with carotid arteries, SOCS3+/− mice were protected confronting Ang II-induced endothelial dysfunction in basilar arteries (Fig. sixB). Responses to nitroprusside were only modestly affected (Fig. sevenC).
SOCS3 deficiency did non alter the pressor response to Ang II.
To investigate furnishings related to claret pressure level, arterial pressure was evaluated in SOCS3+/+ and SOCS3+/− mice. Blood pressure level was similar in both strains treated with saline or Ang II (Fig. 6C). Thus global SOCS3 deficiency did not affect the pressor response to Ang Ii.
To define the importance of SOCS3 during infusion of a nonpressor dose of Ang Two, mice were treated with 0.28 mg/kg Ang II per day for xiv days. This dose of Ang Ii did non alter blood pressure in either strain of mice (Fig. viiD). In addition, acetylcholine- and nitroprusside-induced responses in carotid arteries were similar (Fig. vii, Due east and F).
Vascular expression of select genes.
In an effort to obtain additional insight into mechanisms, we measured mRNA levels of select genes previously implicated in vascular dysfunction (Table one). SOCS3 deficiency was associated with reduced expression of eNOS, SOD1, and SOD2. In dissimilarity, nosotros detected an increase in AT1-R expression in SOCS3+/− mice. IL-6 expression was like between genotypes and was significantly increased following Ang II infusion.
SOCS3+/+ | SOCS3+/+ | SOCS3+/− | SOCS3+/− | |
---|---|---|---|---|
Cistron | + Vehicle | + Ang II | + Vehicle | + Ang Two |
eNOS | 1 ± 0.21 | i.49 ± 0.33 | 0.33 ± 0.17* | 0.54 ± 0.17 |
SOD1 | 1 ± 0.xiv | 0.42 ± 0.xiii* | 0.56 ± 0.12* | 0.40 ± 0.14* |
SOD2 | 1 ± 0.22 | 0.27 ± 0.07* | 0.85 ± 0.05 | 0.34 ± 0.16 |
ATane-R | 1 ± 0.27 | 3.44 ± 0.96 | 2.eighteen ± 0.36* | ii.32 ± 0.35 |
IL-6 | one ± 0.28 | 23.97 ± 9.87* | 0.92 ± 0.55 | 15.34 ± half-dozen.06*† |
To determine whether observed increases in AT1-R expression translated to functional changes, we examined constrictor effects of Ang II in aorta and peripheral arteries. Effects of Ang Two on vascular tone were like in WT and SOCS3+/− mice (Fig. 8). Because expression of AT1-R was relatively depression in aorta (Ct values of ∼32), these results suggest that small differences in AT1-R mRNA levels between strains did not translate to functional effects on vascular tone.
Bone marrow-derived cells scarce in SOCS3 protect against systemic furnishings of Ang II.
To this point, our findings propose that the impact of SOCS3 depends on whether Ang Two was administrated locally or systemically. In considering mechanisms that might account for these differences, we considered the emerging part for hematopoietic cells in hypertension (49, 55). Thus we tested the hypothesis that deficiency in SOCS3 in bone marrow-derived cells would protect against Ang II-induced endothelial role. After mouse recovery from bone marrow transplantation, FACS analysis confirmed effective reconstitution of cells in the diverse groups (Fig. ix). For example, 94% of bone marrow-derived cells in SOCS3+/− mice were reconstituted with WT (CD45.1) bone marrow (Fig. nine). In previous studies, a reconstitution charge per unit of ∼95% was considered successful for standard bone marrow transplantation (four, 10).
Mice were then infused with either saline or Ang II (1.4 mg/kg per day) for 14 days followed past examination of vascular office. WT (CD45.one) into SOCS3+/+ and SOCS3+/− into SOCS3+/− bone marrow chimeras exhibited vascular function consistent with nonirradiated controls (Fig. 10, A and B). For example, acetylcholine-induced relaxation in arteries from the WT (CD45.1) into SOCS3+/+ group was reduced by ∼lx% (P < 0.05) (Fig. 10A), whereas the majority of Ang II-induced endothelial dysfunction was prevented in the SOCS3+/− into SOCS3+/− group (Fig. tenB). Vascular responses to nitroprusside and U46619 were similar in these corresponding groups (data non shown).
Reconstitution of lethally irradiated WT (CD45.1) mice with SOCS3+/− bone marrow protected against detrimental effects of Ang II on endothelial dysfunction (Fig. 10C). In contrast, irradiated SOCS3+/− mice reconstituted with WT (CD45.one) bone marrow exhibited exacerbated Ang II-induced vascular dysfunction (Fig. 10D). For ease of comparison, maximum vascular effects of acetylcholine are presented in Fig. 10E. Nitroprusside-induced relaxation and U46619-induced contraction of carotid arteries was like in all groups (data not shown).
Bone marrow-derived cells deficient in SOCS3 reduced the pressor response to Ang II.
Blood force per unit area was similar in groups infused with saline (Fig. 10F), but the pressor response to Ang 2 was reduced in WT (CD45.1) mice reconstituted with bone marrow from SOCS3+/− mice [compared with SOCS3+/− mice reconstituted with WT (CD45.1) bone marrow] (Fig. xF). These information suggest that deficiency of SOCS3 in bone marrow-derived cells has benign effects on blood pressure during hypertension.
Direct vascular effects of Ang II are not affected by the SOCS3 genotype of os marrow-derived cells.
To examination whether SOCS3 in bone marrow-derived cells alters straight effects of Ang II on endothelial office, arteries were isolated from each group of mice later bone marrow transplantation, incubated with saline or Ang 2 (ane nM) overnight, followed by evaluation of vascular part. Consistent with previous results, Ang II did non modify endothelial role in the WT (CD45.i) into SOCS3+/+ grouping (Fig. 11A). Effects of Ang II on acetylcholine-induced responses in the SOCS3+/− into SOCS3+/− group were like to that seen in nonirradiated SOCS3+/− mice (Fig. 11B). Vascular responses to acetylcholine in SOCS3+/− into WT (CD45.i) and WT (CD45.1) into SOCS3+/− groups were also similar to those in nonirradiated SOCS3+/+ and SOCS3+/− mice (Fig. xi, C and D). Responses of arteries to nitroprusside and U46619 were similar in these groups (data not shown). These information suggest that the SOCS3 genotype of bone marrow-derived cells does not influence directly effects of Ang 2 on the vessel wall.
DISCUSSION
There are several major findings in this written report. Outset, partial genetic deficiency in SOCS3 had no effect on vascular responses under normal conditions but augmented direct furnishings of Ang II on endothelial part. These findings suggest that SOCS3 protects against local effects of Ang Ii on the vessel wall. Second, in relation to mechanisms, local effects of Ang Two on vascular role in SOCS3+/− mice were prevented by inhibition of NF-κB, IL-6, STAT3, or superoxide, suggesting that SOCS3 inhibits prooxidant and proinflammatory elements. Third, baseline arterial pressure and the pressor response to Ang Ii were not altered in SOCS3+/− mice, suggesting that a global reduction in SOCS3 does not protect confronting pressor effects of Ang Ii. 4th, systemic assistants of Ang 2 impaired endothelial part in WT mice but had surprisingly little consequence on endothelial part in SOCS3+/− mice. This protective effect of SOCS3 deficiency on the vasculature extended to a resistance avenue supplying the encephalon. Fifth, bone marrow derived-cells deficient in SOCS3 protected against endothelial dysfunction and increases in arterial pressure produced past systemic Ang 2. This conclusion is based on the observations that reconstitution with SOCS3+/− bone marrow protected WT mice against endothelial dysfunction, whereas SOCS3+/− mice reconstituted with WT os marrow exhibited enhanced endothelial dysfunction. Collectively, these information provide the starting time evidence that SOCS3 exerts divergent effects on vascular function depending on whether the source of Ang Two is local or circulating. Bone marrow-derived cells scarce in SOCS3 protect confronting Ang Two-induced vascular dysfunction and hypertension.
Local vascular effects of Ang 2 are augmented by genetic deficiency in SOCS3: Role of oxidant- and immune-related mechanisms.
Both systemic (circulating) and locally derived Ang II contribute to effects of the peptide on vascular function (sixteen). One of our models tested direct effects of Ang II on the vessel wall, without activating cells in other organ systems or compartments. This approach avoids potential misreckoning effects of increases in arterial force per unit area when Ang II is administered systemically or centrally.
With the employ of this vessel-culture model, Ang Ii produces concentration-dependent effects on endothelial function (28). We confirmed that a low concentration of Ang II (ane nM) does non change endothelial function in vessels from normal mice (12). Interestingly, the degree of impairment of endothelial office in arteries treated with 1 nM Ang II in SOCS3+/− mice was like in magnitude to that produced by a x-fold higher concentration of Ang II in SOCS3+/+ mice. Thus loss of only one copy of the SOCS3 cistron essentially increased sensitivity of vessels to direct furnishings of Ang Two.
IL-6 and STAT3 signaling contribute to Ang Two-induced endothelial dysfunction (28, 51). SOCS3 inhibits STAT3- and IL-6-dependent effects in other models (52). In relation to vascular disease and hypertension, vascular expression of SOCS3 increases during chronic systemic administration of Ang Ii (28). Although such findings raised questions regarding its role, the functional importance of SOCS3 had non been previously evaluated. To our knowledge, the present experiments provide the beginning insight into the functional importance of SOCS3 in intact vessels.
Ang II promotes oxidative stress (forty). Pharmacological or genetic approaches that target superoxide or NADPH oxidase protect the vasculature from furnishings of Ang II (15, 37). A key mechanism underlying Ang Two-induced endothelial dysfunction involves decreased bioavailability of NO resulting from the interaction between NO and superoxide (43). Consistent with these concepts, tempol reversed Ang II-induced endothelial dysfunction in SOCS3+/− mice.
Expression of IL-half dozen and activation of STAT3 are required for Ang II to increase vascular superoxide (28, 51). Oxidative stress and inflammation interact through common feed-forward mechanisms (53). Ang II activates NF-κB and increases expression of IL-6 (2). A new finding was that endothelial dysfunction in SOCS3+/− mice was prevented past inhibitors of IL-vi or STAT3.
NF-κB is a ubiquitously expressed transcription factor, involved in regulation of an array of genes, including ones important in vascular pathophysiology (23). Despite the fact that Ang Ii activates NF-κB in vascular cells and vessels (fourteen, 46), few studies take examined its impact in relation to endothelial role. In the present studies, the local effect of Ang Two on endothelial function in SOCS3+/− mice was prevented by an inhibitor of NF-κB.
Function of SOCS3 in hypertension.
Systemic delivery of Ang 2 is one of the well-nigh common approaches to experimentally produce hypertension. In the present study, the pressor dose of Ang II increased arterial pressure by ∼xl mmHg compared with vehicle in both WT and SOCS3+/− mice. Although these results in WT are consistent with previous studies using radiotelemetry or tail-cuff methods to measure arterial pressure level, nosotros cannot exclude the possibility that modest differences in claret pressure level between strains were missed with the nowadays arroyo. Because Ang II can induce vascular dysfunction through both blood pressure-dependent and -contained mechanisms (5), we too tested effects of a nonpressor dose of Ang Ii. Consequent with previous studies, infusion of Ang II at 0.28 mg/kg per day did non alter blood pressure or endothelial dysfunction in either strain of mice (31).
Deficiency in SOCS3 protects against systemic Ang II-induced endothelial dysfunction.
The pressor dose of Ang II reduced endothelial role in carotid arteries from WT mice. Consequent with previous piece of work using scavengers of superoxide and Nox2-deficient animals (12, 28, 51), this loss of endothelial function was reversed by a scavenger of superoxide. Unexpectedly, systemic Ang II had niggling event on endothelial part in arteries from SOCS3+/− mice. This protective effect of SOCS3 deficiency extended to a resistance vessel supplying encephalon. Thus SOCS3 deficiency augmented local effects of Ang Ii but protected the vasculature in response to systemic Ang Ii.
Vessel-incubation and cell-civilisation models have been used to examine direct effects of Ang Ii previously (three, 28, 51). In studies evaluating the role of ROS, Nox2, IL-6, IL-x, and STAT3, endothelial function was qualitatively similar whether Ang II was administered locally to isolated vessels or systemically (28, 51). In our experience, the present experiments are the first where the 2 models differed in relation to furnishings of Ang II on endothelial function. Such results raised questions regarding the possible role of SOCS3 in nonvascular cells, particularly in bone marrow-derived cells. A limitation of this approach is that, similar studies done in jail cell culture, the elapsing of the vessel incubation studies was non as long as the more chronic studies in which osmotic minipumps were used to deliver Ang II. As noted, all the same, this in vitro arroyo has been predictive of effects in vivo in the past and for a large literature that examined effects of Ang Two using vascular cells in culture.
Hematopoietic SOCS3+/− cells protect against Ang II-dependent endothelial dysfunction and hypertension.
Afterward confirming the efficacy of transplantation, we institute that SOCS3+/− bone marrow derived-cells protected against endothelial dysfunction and increases in arterial pressure produced by systemic assistants of Ang II. Ang 2-induced top in blood pressure was significantly attenuated in irradiated WT (CD45.1) mice reconstituted with SOCS3+/− bone marrow. These results provide straight evidence that the beneficial effects of SOCS3+/− bone marrow extend to claret pressure. SOCS3+/− to WT (CD45.1) os marrow chimeras accept SOCS3+/− bone marrow, which was protective, but a SOCS3+/+ vasculature and were not predisposed to the detrimental effects of Ang Two. Thus the reduced claret force per unit area seen in SOCS3+/− to WT (CD45.1) bone marrow chimeras may outcome from lacking Ang II detrimental furnishings on the vessel wall in combination with protective effects from SOCS3 deficiency in other cells.
Bone marrow-derived stem cells contain ii populations of cells, hematopoietic and mesenchymal stem cells (24). Hematopoietic cells are precursors to all types of claret cells, whereas mesenchymal stem cells can differentiate into other cell types, including endothelial cells (44), which provide a microenvironment supporting hematogenesis (24). With standard protocols for bone marrow transplantation (26), mesenchymal stalk cells are not transplanted with hematopoietic stem cells (33, 35).
The role of SOCS3 can vary in different models and cell types (vii, 32, 57). Although SOCS3 is often considered a suppressor of proinflammatory signaling (vii), deficiency in SOCS3 tin can result in anti-inflammatory furnishings (32, 57). With consideration that IL-vi can elicit both pro- and anti-inflammatory effects in other models (fifty),, the present results back up the possibility that SOCS3 functions as a determinant of pro- or anti-inflammatory effects of Ang 2 and maybe downstream IL-6 signaling. In relation to these concepts, it is interesting that Ang II-induced hypertension is exaggerated in bone marrow-specific AT1-R-deficient mice (9), which suggests a protective effect of Ang II signaling in allowed cells. We speculate that this protective effect may involve activating IL-six anti-inflammatory signaling. Future studies would need to be designed to explore this concept farther.
Although studies to date take non defined the exact prison cell subtype(south) that underlies protective furnishings of bone marrow transfer, nosotros anticipate that beneficial effects most probable result from cells within the leukocyte lineage. A contribution by red blood cells is highly unlikely, as those cells were lysed during training for transplantation. On the basis of results from previous studies, macrophages may be promising candidates for beneficial effects of SOCS3 deficiency (38, 57). Additional studies would exist needed to examination this possibility.
Local vascular effects of Ang II in the hematopoietic SOCS3+/− model.
The depression concentration of Ang II used in the present experiments did non alter endothelial function in lethally irradiated SOCS3+/+ mice reconstituted with CD45.1 WT os marrow. Such results are consistent with effects of Ang Ii on vessels from nonirradiated SOCS3+/+ mice. Similarly, local furnishings of Ang II on endothelial function of lethally irradiated SOCS3+/− mice reconstituted with SOCS3+/− bone morrow were consistent with nonirradiated controls. Both experiments suggest that bone marrow transplantation per se did not alter vascular function. These results further advise that circulating hematopoietic cells did non alter the affect of SOCS3 in relation to local (direct) effects of Ang II on the vessel wall. Collectively, these combined approaches suggest that the endothelial dysfunction produced by Ang 2 in arteries from SOCS3+/− mice can exist attributed to the local effects of SOCS3 inside the vessel wall (within resident vascular cells).
In conclusion, both genetic and pharmacological approaches provided stiff prove that SOCS3 plays a divergent role in relation to local vs. systemic effects of Ang Ii on the vasculature. Endothelial dysfunction produced by local Ang II was augmented in SOCS3+/− arteries, suggesting that, under normal conditions, SOCS3 protects vessels confronting detrimental furnishings of Ang II past suppressing IL-vi/STAT3 signaling events. Systemic infusion of a pressor dose of Ang Ii, which induced endothelial dysfunction in arteries from WT mice, surprisingly caused minimal impairment in arteries from SOCS3+/− mice, suggesting that normal expression of SOCS3 facilitates detrimental effects of Ang 2 on vascular function. Last, results from bone marrow transplantation studies suggest that bone marrow-derived cells are responsible for protective effects of SOCS3 deficiency on vascular office. Understanding mechanisms by which SOCS3+/− cells protect against Ang Two may eventually back up the development of new therapeutic strategies for hypertension and associated end-organ damage.
Recent studies accept begun to highlight the importance of bone marrow in hypertension, including the role of lymphocyte adapter poly peptide (49, 55). The present findings extend this concept by providing new insight into functional effects of SOCS3 in vascular and bone marrow compartments. As noted past u.s.a., and others (17, 49), complete loss of gene expression or protein function is unusual. Thus is it noteworthy that merely partial deficiency of SOCS3 (loss of one cistron copy) was sufficient to substantially modify furnishings of Ang II on vascular function and the bear upon of os marrow-derived cells.
GRANTS
This work was supported by the
DISCLOSURES
No conflicts of interest, fiscal or otherwise, are alleged by the authors.
AUTHOR CONTRIBUTIONS
Y.L. and F.1000.F. formulation and design of research; Y.Fifty., D.A.1000., Thousand.L.M., and L.Fifty.P. performed experiments; Y.L. and F.M.F. analyzed data; Y.Fifty., L.Fifty.P., and F.K.F. interpreted results of experiments; Y.L. prepared figures; Y.L. drafted manuscript; Y.L. and F.M.F. edited and revised manuscript; Y.50., D.A.K., M.L.M., L.L.P., and F.M.F. approved last version of manuscript.
REFERENCES
- one. Interference with PPARgamma signaling causes cognitive vascular dysfunction, hypertrophy, and remodeling. Hypertension 51: 867–871, 2008.
Crossref | PubMed | ISI | Google Scholar . - 2. The nuclear factor-κB-interleukin-6 signalling pathway mediating vascular inflammation. Cardiovasc Res 86: 211–218, 2010.
Crossref | PubMed | ISI | Google Scholar . - 3. Adventitia-derived hydrogen peroxide impairs relaxation of the rat carotid avenue via smoothen muscle cell p38 mitogen-activated protein kinase. Antioxid Redox Betoken xv: 1507–1515, 2011.
Crossref | PubMed | ISI | Google Scholar . - 4. A novel molecule Me6TREN promotes angiogenesis via enhancing endothelial progenitor cell mobilization and recruitment. Sci Rep four: 6222, 2014.
Crossref | PubMed | ISI | Google Scholar . - five. Role of Nox isoforms in angiotensin Ii-induced oxidative stress and endothelial dysfunction in encephalon. J Appl Physiol 113: 184–191, 2012.
Link | ISI | Google Scholar . - 6. Quantification of mRNA for endothelial NO synthase in mouse blood vessels by real-fourth dimension polymerase chain reaction. Arterioscler Thromb Vasc Biol 22: 611–616, 2002.
Crossref | PubMed | ISI | Google Scholar . - 7. SOCS3 negatively regulates IL-6 signaling in vivo. Nat Immunol 4: 540–545, 2003.
Crossref | PubMed | ISI | Google Scholar . - 8. The cooperative roles of inflammation and oxidative stress in the pathogenesis of hypertension. Antioxid Redox Signal twenty: 102–120, 2014.
Crossref | PubMed | ISI | Google Scholar . - 9. A office for angiotensin II type i receptors on bone marrow-derived cells in the pathogenesis of angiotensin II-dependent hypertension. Hypertension 55: 99–108, 2010.
Crossref | PubMed | ISI | Google Scholar . - ten. Expression of HLA grade Ii molecules in humanized NOD. Rag1KO IL2RgcKO mice is disquisitional for evolution and function of human T and B cells. PLoS 1 6: e19826, 2011.
Crossref | PubMed | ISI | Google Scholar . - 11. Critical role for CuZn-superoxide dismutase in preventing angiotensin II-induced endothelial dysfunction. Hypertension 46: 1147–1153, 2005.
Crossref | PubMed | ISI | Google Scholar . - 12. Endogenous interleukin-10 inhibits angiotensin II-induced vascular dysfunction. Hypertension 54: 619–624, 2009.
Crossref | PubMed | ISI | Google Scholar . - 13. Increased superoxide and vascular dysfunction in CuZnSOD-deficient mice. Circ Res 91: 938–944, 2002.
Crossref | PubMed | ISI | Google Scholar . - fourteen. Structure, endothelial office, cell growth, and inflammation in blood vessels of angiotensin II-infused rats: role of peroxisome proliferator-activated receptor-γ. Circulation 105: 2296–2302, 2002.
Crossref | PubMed | ISI | Google Scholar . - xv. Upregulation of Nox1 in vascular polish musculus leads to impaired endothelium-dependent relaxation via eNOS uncoupling. Am J Physiol Heart Circ Physiol 299: H673–H679, 2010.
Link | ISI | Google Scholar . - 16. Vascular renin-angiotensin system and vascular protection. J Cardiovasc Pharm 22, Suppl five: S1–S9, 1993.
Crossref | PubMed | ISI | Google Scholar . - 17. Protecting against vascular disease in brain. Am J Physiol Centre Circ Physiol 300: H1566–H1582, 2011.
Link | ISI | Google Scholar . - 18. Cerebral vascular effects of angiotensin II: New insights from genetic models. J Cereb Blood Flow Metab 26: 449–455, 2006.
Crossref | PubMed | ISI | Google Scholar . - 19. Selective cognitive vascular dysfunction in Mn-SOD-deficient mice. J Appl Physiol 100: 2089–2093, 2006.
Link | ISI | Google Scholar . - 20. Responses of carotid artery in mice deficient in expression of the gene for endothelial NO synthase. Am J Physiol Eye Circ Physiol 274: H564–H570, 1998.
Link | ISI | Google Scholar . - 21. New physiological concepts of the renin-angiotensin system from the investigation of precursors and products of angiotensin I metabolism. Hypertension 55: 445–452, 2010.
Crossref | PubMed | ISI | Google Scholar . - 22. Cytochrome b-558 alpha-subunit cloning and expression in rat aortic smooth muscle cells. Biochim Biophys Acta 1231: 215–219, 1995.
Crossref | PubMed | ISI | Google Scholar . - 23. NF-κB transcription factor: Role in the pathogenesis of inflammatory, autoimmune, and neoplastic diseases and therapy implications. Clin Ter 152: 249–253, 2001.
PubMed | Google Scholar . - 24. Plasticity of bone marrow-derived stem cells. Stem Cells 22: 487–500, 2004.
Crossref | PubMed | ISI | Google Scholar . - 25. Angiotensin 2 induces interleukin-6 transcription in vascular shine muscle cells through pleiotropic activation of nuclear cistron-κB transcription factors. Circ Res 84: 695–703, 1999.
Crossref | PubMed | ISI | Google Scholar . - 26. CD8 T-cell recognition of macrophages and hepatocytes results in immunity to Listeria monocytogenes . Infect Immun 64: 3632–3640, 1996.
PubMed | ISI | Google Scholar . - 27. Oxidative stress and endothelial dysfunction: Clinical evidence and therapeutic implications. Trends Cardiovasc Med 24: 165–169, 2014.
Crossref | PubMed | ISI | Google Scholar . - 28. Minor-molecule inhibitors of signal transducer and activator of transcription 3 protect against angiotensin II-induced vascular dysfunction and hypertension. Hypertension 61: 437–442, 2013.
Crossref | PubMed | ISI | Google Scholar . - 29. Expression of phagocyte NADPH oxidase components in human endothelial cells. Am J Physiol Eye Circ Physiol 271: H1626–H1634, 1996.
Link | ISI | Google Scholar . - 30. Angiotensin receptors: Interpreters of pathophysiological angiotensinergic stimuli. Pharmacol Rev 67: 754–819, 2015.
Crossref | PubMed | ISI | Google Scholar . - 31. A mouse model of angiotensin Two slow pressor response: Part of oxidative stress. J Am Soc Nephrol 13: 2860–2868, 2002.
Crossref | PubMed | ISI | Google Scholar . - 32. Loss of SOCS3 in T helper cells resulted in reduced immune responses and hyperproduction of interleukin x and transforming growth factor-β1. J Exp Med 203: 1021–1031, 2006.
Crossref | PubMed | ISI | Google Scholar . - 33. Bone marrow stromal cells: Label and clinical application. Crit Rev Oral Biol Med x: 165–181, 1999.
Crossref | PubMed | Google Scholar . - 34. The interaction between coronary endothelial dysfunction, local oxidative stress, and endogenous nitric oxide in humans. Hypertension 51: 127–133, 2008.
Crossref | PubMed | ISI | Google Scholar . - 35. Chromosomal analysis of bone marrow stromal fibroblasts in allogeneic HLA compatible sibling bone marrow transplantations. Leuk Res 11: 661–663, 1987.
Crossref | PubMed | ISI | Google Scholar . - 36. SOCS3 is essential in the regulation of fetal liver erythropoiesis. Cell 98: 617–627, 1999.
Crossref | PubMed | ISI | Google Scholar . - 37. Nox1 is involved in angiotensin Ii-mediated hypertension: a study in Nox1-deficient mice. Apportionment 112: 2677–2685, 2005.
Crossref | PubMed | ISI | Google Scholar . - 38. Signaling by IL-6 promotes alternative activation of macrophages to limit endotoxemia and obesity-associated resistance to insulin. Nat Immunol 15: 423–430, 2014.
Crossref | PubMed | ISI | Google Scholar . - 39. Selective inhibition of NF-κB activation by a peptide that blocks the interaction of NEMO with the IκB kinase circuitous. Science 289: 1550–1554, 2000.
Crossref | PubMed | ISI | Google Scholar . - forty. Angiotensin Ii cell signaling: Physiological and pathological furnishings in the cardiovascular system. Am J Physiol Cell Physiol 292: C82–C97, 2007.
Link | ISI | Google Scholar . - 41. Early intrathymic precursor cells acquire a CD4(low) phenotype. J Immunol 160: 1735–1741, 1998.
PubMed | ISI | Google Scholar . - 42. A new await at the renin-angiotensin system—focusing on the vascular system. Peptides 32: 2141–2150, 2011.
Crossref | PubMed | ISI | Google Scholar . - 43. Antioxidants block angiotensin Two-induced increases in blood pressure and endothelin. Hypertension 38: 655–659, 2001.
Crossref | PubMed | ISI | Google Scholar . - 44. Mesenchymal stem cells can exist differentiated into endothelial cells in vitro. Stalk Cells 22: 377–384, 2004.
Crossref | PubMed | ISI | Google Scholar . - 45. Localization of a constitutively active, phagocyte-like NADPH oxidase in rabbit aortic adventitia: Enhancement by angiotensin II. Proc Natl Acad Sci USA 94: 14483–14488, 1997.
Crossref | PubMed | ISI | Google Scholar . - 46. Angiotensin II activates nuclear transcription factor-κB in aorta of normal rats and in vascular smooth muscle cells of AT1 knockout mice. Nephrol Dial Transplant xvi, Suppl i: 27–33, 2001.
Crossref | PubMed | ISI | Google Scholar . - 47. Endothelial dysfunction and blood force per unit area variability in selected inbred mouse strains. Arterioscler Thromb Vasc Biol 22: 42–48, 2002.
Crossref | PubMed | ISI | Google Scholar . - 48. PPARγ agonist rosiglitazone improves vascular function and lowers blood force per unit area in hypertensive transgenic mice. Hypertension 43: 661–666, 2004.
Crossref | PubMed | ISI | Google Scholar . - 49. Lymphocyte adaptor protein LNK deficiency exacerbates hypertension and end-organ inflammation. J Clin Invest 125: 1189–1202, 2015.
Crossref | PubMed | ISI | Google Scholar . - l. The pro- and anti-inflammatory properties of the cytokine interleukin-six. Biochim Biophys Acta 1813: 878–888, 2011.
Crossref | PubMed | ISI | Google Scholar . - 51. IL-6 deficiency protects against angiotensin Ii induced endothelial dysfunction and hypertrophy. Arterioscler Thromb Vasc Biol 27: 2576–2581, 2007.
Crossref | PubMed | ISI | Google Scholar . - 52. Consecration of the cytokine bespeak regulator SOCS3/CIS3 equally a therapeutic strategy for treating inflammatory arthritis. J Clin Invest 108: 1781–1788, 2001.
Crossref | PubMed | ISI | Google Scholar . - 53. Inflammation, immunity, and hypertensive finish-organ damage. Circ Res 116: 1022–1033, 2015.
Crossref | PubMed | ISI | Google Scholar . - 54. Congenic interval of CD45/Ly-five congenic mice contains multiple genes that may influence hematopoietic stem jail cell engraftment. Blood 115: 408–417, 2010.
Crossref | PubMed | ISI | Google Scholar . - 55. Immune mechanisms in arterial hypertension. J Am Soc Nephrol 27: 677–86, 2016.
Crossref | PubMed | ISI | Google Scholar . - 56. A new assay method for late CFU-S formation and long-term reconstituting action using a minor number of pluripotent hemopoietic stem cells. Stem Cells 20: 241–248, 2002.
Crossref | PubMed | ISI | Google Scholar . - 57. IL-6 induces an anti-inflammatory response in the absence of SOCS3 in macrophages. Nat Immunol 4: 551–556, 2003.
Crossref | PubMed | ISI | Google Scholar . - 58. Regulation of cytokine signaling by the SOCS and Spred family proteins. Keio J Med 58: 73–83, 2009.
Crossref | PubMed | Google Scholar .
Source: https://journals.physiology.org/doi/10.1152/ajpheart.00204.2016
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