bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mycophenolate Mofetil Attenuates Hypertension in an Experimental Model of Systemic Lupus Erythematosus
Authors: Taylor Erin , Strawder Akil , Ryan Michael 
Published: November 2023

Mycophenolate mofetil (MMF) is an immunosuppressive agent that selectively depletes proliferating lymphocytes and is commonly used to prevent organ transplant rejection or treat autoimmune disease. Systemic lupus erythematosus (SLE) is a chronic multisystem autoimmune disorder that predominately affects women of childbearing age and is associated with a high rate of hypertension, renal injury, and cardiovascular disease. Recent clinical evidence suggests that treatment with MMF can reduce blood pressure in patients with rheumatoid arthritis or psoriasis; however, whether MMF can be effectively utilized in the control of blood pressure during SLE remains unclear. Because immune dysregulation and inflammation have been linked to the pathophysiology of essential hypertension, we hypothesized that MMF will attenuate hypertension and renal injury in an experimental mouse model of SLE. Female SLE (NZBWF1) and control (NZW) mice, aged 26 weeks, were injected intraperitoneally with 5% dextrose (vehicle) or MMF daily at a rate of 60 mg/kg/day for eight weeks. CD45R+ B cells were lower in the peripheral blood of SLE mice treated with MMF for eight weeks (19.5±1.3% SLE‐Vehicle vs. 5.2±1.5% SLE‐MMF, p< 0.01), but the levels of both CD4+ and CD8+ T cells were unchanged. Circulating levels of anti‐dsDNA IgG auto antibodies, a marker of SLE disease activity, were higher in SLE mice as compared to control mice (789±120 vs. 161±57 units/mL, p<0.0001), and were significantly lower in mice treated for eight weeks with MMF (SLE‐MMF: 321±90; p<0.05 vs. SLE‐Vehicle). Urinary albumin excretion, an indicator of glomerular injury, was increased in SLE mice as compared to controls (5.6±1.9 vs. 0.11±0.02 ng/day, p<0.0001), and was lower in SLE mice treated with MMF (SLE‐MMF: 0.38±0.20 ng/day; p<0.001 vs. SLE‐Vehicle). Mean arterial pressure (MAP; mmHg) measured in conscious mice by carotid catheter was higher in SLE mice than in control mice (141±3 vs. 120±3, p<0.05). MAP was significantly lower in SLE mice treated with MMF when compared to vehicle treated SLE mice (SLE‐MMF: 120±5; p<0.001 vs. SLE‐Vehicle). These data suggest that MMF treatment may have added clinical benefit for patients with SLE by helping to control blood pressure, a major contributor to cardiovascular risk in this population. Moreover, given that MMF selectively depleted CD45R+ B cells, these data provide additional evidence that B cells and the production of auto antibodies mechanistically contribute to the pathogenesis of hypertension during SLE.Support or Funding InformationResearch supported by: VA# I01BX002604‐01A2 (MJR), T32HL105324 (EBT), HL051971 (UMMC‐Physiology)
Improvement in Blood Pressure and Renal Injury Following Vagal Nerve Stimulation
Authors: Maloy Charles I , Fairley Amber S , Pham Grace S , Mathis Keisa W 
Published: November 2023

The concept that autoimmunity and its subsequent inflammation could play a role in the pathogenesis of hypertension has recently been supported by many studies. Such inflammatory responses are also associated with end organ damage in hypertension. Recent studies have proposed a novel pathway, the cholinergic anti‐inflammatory pathway, which may combat this inflammation and prevent the subsequent damage. Specifically, stimulation of the vagus nerve has been shown to reduce inflammation via the cholinergic anti‐inflammatory pathway. Systemic Lupus Erythematosus (SLE), an autoimmune disease with profound systemic inflammation and a high prevalence of hypertension, provides an appropriate model to test whether an impaired cholinergic anti‐inflammatory pathway plays a role in development of chronic inflammation and hypertension. We tested the hypothesis that pharmacological stimulation of the vagus nerve reduces blood pressure and improves renal injury and function in SLE mice (NZBWF1). Starting at 30 weeks of age, female SLE and control (NZW) mice were treated twice per week over four weeks with CNI‐1493 (Semapimod hydrochloride; 8 mg/kg, IP), which has been shown to stimulate the vagus nerve. Saline was used as the vehicle treatment. At the end of the study, mean arterial pressure (mmHg) was higher in SLE mice compared to controls (143±11 vs. 116±4; p=0.003; n=3–5/group). Treatment with CNI‐1493 attenuated the development of hypertension in the SLE mice (130 ± 4), but did not alter mean arterial pressure in controls (119 ± 5). Renal injury in the form of albuminuria (albumin excretion rate; μg/day) was increased in SLE mice compared to controls (4409±2519 vs. 4 ± 1; p=0.002; n =3–6/group). Albumin excretion rate was diminished in CNI‐1493‐treated SLE mice (420±410; p = 0.008). Renal blood flow (mL/min*g kidney weight) was measured and renal vascular resistance was calculated (mmHg*min*g kidney weight/mL) as indices of renal function. CNI‐1493‐treated SLE mice had higher renal blood flow (3.0 vs. 2.5±0.1; n=1–2/group) and lower renal vascular resistance (21.9 vs. 23.9±1; n=1–2/group) compared to SLE mice treated with saline. These data suggest that stimulation of the vagus nerve may protect the kidney and prevent SLE hypertension; however, future studies are warranted to determine how this occurs. Taken together, our findings suggest that the vagally‐mediated cholinergic anti‐inflammatory pathway plays a mechanistic role in the development hypertension in the setting of chronic inflammation.Support or Funding InformationStudies supported by the AHA (#14SDG18320033) and UNTHSC (Faculty Pilot Grant and Research Seed Funding)
Stem Cells Improved the Ability of the Contralateral Kidney to Excrete Sodium in the Renovascular Hypertension Induced by Renal Artery Stenosis
Authors: Varela Vanessa Araujo , de Oliveira‐Sales Elizabeth Barbosa , Shimoura Caroline Gusson , Maquigussa Edgar , Borges Fernanda Teixeira , Boim Mirian Aparecida 
Published: November 2023

It was previously demonstrated that mesenchymal stem cells (MSC) improved renal function and renovascular hypertension in consequence of unilateral renal artery stenosis induced by 2 kidneys‐1clip model (2K‐1C) through immunomodulatory actions and by inducing neoangiogenesis. However, the urinary sodium loss was not corrected by MSC. Here, we investigated the tubular function of both stenotic and contralateral kidneys and the effect of MSC treatment by evaluating diuresis, natriuresis and the expression of the main water and sodium transporters. Adult Wistar rats were allocated in the following groups: Control (C, n=6), C+MSC (n=5), 2K‐1C (n=5), 2K‐1C+MSC (n=5). MSC were infused in the 3rd and in the 5th weeks after clipping through the tail vein (2×105 cells). Systolic blood pressure (BP) was monitored weekly by plethysmography. Six weeks after clipping, 24 hours urine and blood samples were collected for biochemical analysis. The glomerular filtration rate (GFR) and the renal plasma flow (RPF) of both kidneys were determined by inulin and PAH clearances respectively. Gene expression of the Na/H exchanger (NHE3), epithelial sodium channel (ENaC), Na/K/ATPase, Na/K/2Cl cotransporter and aquaporin 1 and 2 (AQP1 and AQP2) were analyzed by RT‐PCR. 2K‐1C animals showed a progressive hypertension and MSC prevented BP to increase further. Urinary flow rate and sodium excretion were reduced in the stenotic kidney, but it was significantly increased in the contralateral kidney of the 2K‐1C animals. A suppression in the AQP1 but not AQP2 expression in the contralateral kidney was responsible for the rise in the urinary volume. In contrast, there was no change in the gene expression of the sodium transporters in the contralateral kidney, suggesting that the natriuresis was not dependent of tubular transport but probably of pressure origin (pressure natriuresis). GFR was significantly reduced in both stenotic and contralateral kidneys whereas RPF was reduced only in the stenotic kidney indicating that the hypertensive contralateral kidney presented signs of deficit of renal function. MSC treatment slightly improved GFR and RPF of both kidneys and caused further increases on diuresis and natriuresis of the contralateral kidney, suggesting that MSC improved the capacity of the contralateral kidney to excrete sodium that in turn could contribute to improve hypertension. In conclusion, in spite of a slight deficit of GFR the contralateral kidney was still able to excrete sodium by a tubular independent mechanism and MSC treatment improved the sodium excretory capacity of the contralateral kidney.Support or Funding InformationSupported by FAPESP and CNPQ.
Conscious Dahl Salt‐Sensitive Rats Excrete a Volume Load Slower than Sprague Dawley Rats Due to a Defect in Thick Ascending Limb Transport
Authors: Saez Fara , Garvin Jeffrey 
Published: November 2023

Dahl salt‐sensitive rats have an impaired excretory ability when compared to the parent Sprague‐Dawley strain due to a renal defect. However, nearly all studies have been performed in anesthetized animals raising the possibility that differences between strains are the result of the anesthesia. Although in vitro data indicate that at least part of the defect is due to enhanced NaCl reabsorption by thick ascending limbs in the salt‐sensitive strain, this has not been demonstrated in conscious, whole‐animal experiments. We hypothesized that conscious Dahl salt‐sensitive rats have an impaired ability to excrete an acute volume load to abnormal thick ascending limb NaCl reabsorption. To test our hypothesis, Dahl salt‐sensitive and Sprague‐Dawley rats were placed in metabolic cages and trained to drink their daily water intake in just two hours creating a modest volume load. On the day of the experiment, rats were given a 1% sucrose solution for just one hour with and without furosemide, an inhibitor of thick ascending limb NaCl reabsorption. Urine was collected every 30 minutes for 3 hours. At 60, 90, 120 and 150 min, cumulative urinary volume was lower in salt‐sensitive compared to Sprague‐Dawley rats (60 min: 1±0.3 vs. 7±1, p<0.05; 90 min: 7±1 vs. 18±2, p<0.01; 120 min: 14±1 vs. 24±1, p<0.01; 18±1 vs. 26±2, p<0.05). By 180 min, cumulative urinary volumes were no longer different. Cumulative urinary Na excretion, expressed as percent of total urinary Na excretion, was also lower in Dahl salt‐sensitive rats (60 min: 43±6 vs. 65±6, p<0.05; 90 min: 74±4 vs. 89±2, p<0.01; 120 min: 87±4 vs. 97±1, p<0.01). Furosemide increased dramatically both cumulative urinary volume and urinary Na excretion, and eliminated the differences between strains. We conclude that conscious Dahl salt‐sensitive rats have a defect in thick ascending limb NaCl reabsorption that impairs their ability to excrete an acute volume load. This defect likely contributes to the salt‐sensitivity of blood pressure in this strain.Support or Funding InformationThis work was supported in part by grants to Jeffrey Garvin from the National Institutes of Health (HL 70985) and to Fara Saez from the American Heart Association (15POST22650010 ).
Vascular Endothelial Growth Factor Down Regulates the Renal Epithelial Sodium Channel
Authors: Koenen Anna , Rettig Rainer , Grisk Olaf 
Published: November 2023

Vascular endothelial growth factor receptor (VEGFR) inhibitors, such as sunitinib, are widely used in tumor therapy. Their clinical use is limited by a rapidly developing arterial hypertension. We found that fractional sodium excretion was significantly reduced in sunitinib‐treated rats without alterations in fractional lithium excretion suggesting increased sodium reabsorption in the distal nephron and/or collecting ducts (CD). Therefore, we tested the hypotheses that sunitinib increases renal epithelial sodium channel (ENaC) expression and alters subcellular ENaC localization in the rat renal CD. Further, we tested if VEGF down regulates ENaC expression in murine cortical CD (M1) cells.Sunitinib [15 mg/(kg*d), n = 7, for 4 days] had no significant effects on renal ENaC subunit mRNA abundances but significantly increased α‐ENaC protein abundance by 57% in the renal medulla. Subcellular localization studies with confocal laser microscopy revealed that sunitinib increased the α‐ENaC subunit within the apical plasma membrane of the principal cells in cortical and medullary CD. The subcellular localization of the β‐ and γ‐ENaC subunits was similar in sunitinib‐treated and sham‐treated animals. In aldosterone‐treated M1 cells, VEGF significantly reduced α‐, β‐ and γ‐ENaC mRNA abundances by 30%, 55% and 40%, respectively. Sunitinib diminished (α‐ and γ‐subunits) or prevented (β‐subunit) these effects. In addition, VEGF significantly decreased α‐ and β‐ENaC protein abundances in M1 cells and sunitinib antagonized these effects.We conclude that VEGF down regulates renal ENaC and that increased ENaC activity may contribute to the pathogenesis of VEGFR inhibitor‐induced arterial hypertension.
Neddylation‐Deficient K712R CUL3 Δ403‐459 Double Mutant Attenuates Proteasome‐Dependent KLHL3 Degradation
Authors: Cornelius Ryan J. , Zhang Chong , Erspamer Kayla J. , Terker Andrew S. , Singer Jeffrey D. , Yang Chao‐Ling , Ellison David H. 
Published: November 2023

Cullin 3 (CUL3) is a member of the cullin RING E3 ubiquitin ligase family that mediates ubiquitylation and degradation of multiple cellular proteins via the proteasome. CUL3 facilitates ubiquitylation‐dependent WNK kinase degradation through the substrate adaptor Kelch‐like 3 (KLHL3). Activation of CUL3 requires a covalent modification called neddylation, in which a NEDD8 molecule is attached to a specific lysine residue. A form of Familial hyperkalemic hypertension (FHHt, or pseudohypoaldosteronism type II) has been shown to result from deletion of CUL3 exon 9 (consisting of 57 amino acid residues; CUL3 Δ403‐459). We showed previously that CUL3 Δ403‐459 is more heavily neddylated; this led to enhanced KLHL3 degradation and increased abundance of WNKs. Here, we sought to determine the molecular mechanism for this effect. We transfected HEK293 cells with a FLAG‐tagged neddylation‐deficient CUL3 plasmid construct in which a point‐mutation (K712R) was introduced at the neddylation site. Immunoprecipitation demonstrated that neddylation was nearly absent in both WT K712R CUL3 and K712R CUL3 Δ403‐459. When compared to CUL3 Δ403‐459, K712R CUL3 Δ403‐459 exhibited less capacity to degrade KLHL3. As a result, WNK4 abundance was lower when KLHL3 was co‐expressed with the K712R CUL3 Δ403‐459, compared with CUL3 Δ403‐459. To examine the mechanism of KLHL3 degradation, we incubated cells with the proteasome inhibitor MG132 for 18 h. This almost completely inhibited KLHL3 degradation; in contrast, inhibition of autophagy with two separate drugs, chloroquine and 3‐methyladenine, had only a modest effect. The results indicate that, 1) neddylation at the 712 lysine residue is important for CUL3 Δ403‐459 function, and 2) KLHL3 degradation, mediated by CUL3 Δ403‐459, occurs predominately via the proteasomal pathway. In summary, the FHHt‐causing CUL3 Δ403‐459 mutation exhibits increased neddylation at lysine 712, which causes proteasomal‐dependent degradation of KLHL3. This likely leads to increased WNK kinase abundance and human disease.Support or Funding InformationWork was supported by National Institutes of Health Grants 2R01DK051496‐15A1 and 5T32DK067864‐10.
NEDD4‐2 reduces electroneutral Cl−/HCO3− exchange in mouse cortical collecting duct
Authors: Pham Truyen Derek , Nanami Masayoshi , Staub Olivier , Sutliff Roy L , Klein Janet D , Eladari Dominique , Chambrey Regine , Wang Xiaonan , Verlander Jill W , Wall Susan M 
Published: November 2023

NEDD4‐2 is a ubiquitin ligase that associates with transport proteins, such as ENaC, resulting in their ubiquitination and then endocytosis and degradation. With global NEDD4‐2 gene ablation, salt‐sensitive hypertension is observed, in part, from the increased renal NaCl transporter expression. While principal cell NEDD4‐2 function has been studied, little is known about NEDD4‐2 within intercalated cells (ICs). Thus, the purpose of this study was to determine the effect of IC NEDD4‐2 ablation on blood pressure and on Cl− absorption in the cortical collecting duct (CCD). As such, we generated an IC‐specific NEDD4‐2 null mouse using Cre‐loxP technology. Blood pressure was measured by radiotelemetry and ion transport was measured in mouse cortical collecting ducts (CCDs) perfused in vitro. Following a high NaCl diet, IC NEDD4‐2 gene ablation markedly stimulated electroneutral Cl−/HCO3− exchange in the mouse CCD and increased mean arterial pressure by ~10 mm Hg. To determine the transporter(s) responsible for this increase in transport, we examined the effect of IC NEDD4‐2 gene ablation on mouse type B IC transporter abundance by immunoblot, immunohistochemistry and immunogold cytochemistry. We observed that IC NEDD4‐2 gene ablation increased ClC‐5 and pendrin protein abundance, but not the H+‐ATPase, AE4 or the Na+‐dependent Cl−/HCO3− exchanger, NDCBE. To determine if pendrin associates with NEDD4‐2 we transfected a rat intercalated cell line with adenovirus expressing Xpress‐tagged NEDD4‐2 and then immunoprecipitated for the Xpress tag. By immunoblot, pendrin was expressed in the Xpress tagged precipitates taken from cells transfected with full length NEDD4‐2, but not in precipitates taken from cells transfected with NEDD4‐2 lacking the C terminus.ConclusionsIC NEDD4‐2 gene ablation contributes to the pathophysiology of salt‐sensitive hypertension, at least in part, by increasing Cl− absorption by ICs, through transporters such as pendrin.Support or Funding InformationInteraction of NEDD4‐2 and Aldosterone in Interacalated Cell Function. Grant Number: DK104125
Short Term Regulation of SGLT2 by Insulin in vivo
Authors: Ghezzi Chiara , Scafoglio Claudio , Liu Jie , Barrio Jorge R , Wright Ernest M 
Published: November 2023

Glucose homeostasis is a complex mechanism that requires the interplay between different organs. The kidney plays a central role in this process by re‐absorbing 99.5% of the filtered glucose in the proximal tubules, where SGLT1 and SGLT2 use the energy provided by the electrochemical gradient of sodium to drive glucose transport.In recent years SGLT2 has received much attention as the target of inhibition by a class of drugs (i.e. dapagliflozin, canagliflozin) that lower blood glucose levels in type II diabetes patients by blocking glucose re‐absorption in the kidney tubules. In the present study, we used [F‐18] fluoro‐dapagliflozin (F‐Dapa), a specific, high‐affinity SGLT2 ligand (KB 4 nM), to study the localization and activity of SGLT2 in the mouse kidney in vivo, by microPET on wild type (WT) and knock‐out mice.Our results showed, as expected, that in WT mice SGLT2 was highly expressed in the kidney. Binding was fast and reached saturation already after 10 minutes. The specificity of F‐Dapa binding was determined using SGLT2−/− and SGLT1−/−‐SGLT2−/− mice, in which binding was reduced to background levels, and competition experiments with phlorizin and dapagliflozin, in which we observed the blockage of F‐Dapa binding and the displacement of the bound ligand.We have previously shown that hSGLT2 expressed in HEK‐293T cells is up‐regulated by insulin due to either a fast insertion of an intracellular pool of transporters into the plasma membrane, or an increase in the transporter catalytic turnover. To determine the effect of insulin on SGLT2 in vivo, we measured the change in F‐Dapa binding to the kidney after insulin injection. Our results showed that immediately after insulin administration, F‐Dapa binding rapidly increased by 30% to a new steady state, and the total binding was displaced by dapagliflozin and phlorizin.In conclusion, our results showed that F‐Dapa is a SGLT2‐specific tracer that can be used to study the protein localization to the brush border membrane of the proximal tubule in vivo. Moreover, using this tool we showed that insulin rapidly recruits an intracellular pool of SGLT2 to the brush border membrane.Support or Funding InformationNIH/NIDDKDK077133
Role of IGF1R in Tubular Remodeling of the Mouse Kidney
Authors: Walczak Elisabeth , Krauson Aram , Iyer Sonali , Nizar Jonathan , Dong Wuxing , Bhalla Vivek 
Published: November 2023

Loop diuretics, commonly prescribed to treat hypertension and edema, increase sodium excretion by inhibiting the sodium‐potassium 2 chloride cotransporter (NKCC2) in the thick ascending limb. Chronic furosemide use leads to diuretic resistance in humans, but the molecular mechanisms are largely unknown. We developed a mouse model of chronic furosemide use to explore its effects on sodium transport and tubular remodeling. Mice treated with furosemide for seven days had greater sensitivity for thiazide diuretics with significantly increased levels of sodium‐chloride cotransporter (NCC), demonstrating compensatory sodium reabsorption of the distal nephron. Furosemide‐treated mice also exhibited tubular hyperplasia. After 21 days, mice treated with furosemide vs. vehicle, had persistently‐elevated NCC expression increased kidney‐to‐body weight ratio, increased tubular hypertrophy of distal convoluted tubule and connecting tubular segments, and changes in IGF‐1 signaling. There was no increase in IGF‐1 mRNA expression, but specific increases in IGF binding proteins (IGFBPs) which are known to sequester IGF‐1 in kidney cells, and IGF‐1 receptor. To further explore the role of IGF‐1 in tubular remodeling, we developed an inducible, pan‐tubular IGF‐1 receptor knockout mouse. Interestingly, furosemide‐treated IGF‐1 receptor (IGF1R) knockout mice lacked the increased kidney‐to‐body mass increase ratio seen in wild‐type mice, but they developed comparable hypertrophy in distal nephron segments and higher expression of NCC compared with furosemide‐treated wild‐type mice. These results suggest IGF1R signaling is involved in renal tubular remodeling of more proximal nephron segments and distinct factors control the tubular hypertrophy of the distal nephron beyond an increase in NCC expression.Support or Funding InformationNIH/NIDDK
Chronic Lithium Treatment Induces Novel Patterns of Pendrin Localization and Expression in the Renal Inner Medulla
Authors: Himmel Nathaniel J. , Wang Yirong , Rodriguez Daniel A. , Sun Michael A. , Blount Mitsi A. 
Published: November 2023

Prolonged lithium treatment is associated with various renal side effects, including hyperchloremic acidosis, and is known to induce inner medullary collecting duct (IMCD) remodeling. In animals treated with lithium, the fraction of intercalated cells (ICs), which are responsible for acid‐base homeostasis, increases as compared to renal principal cells (PCs). In order to investigate the intricacies of lithium‐induced IMCD remodeling, male Sprague Dawley rats were fed a 0.3% LiCl‐enriched diet for 1, 2, 3, 6, 9, or 12 weeks. Urine osmolality began to decrease at 1 week, and from 2–12 weeks, animals were severely polyuric. Beginning at 6 weeks, approximately one‐quarter of cells counted in initial IMCD sections expressed vATPase, an IC marker. These cells were localized in portions of the IM where ICs are not normally found. Pendrin, a Cl−/ HCO3− exchanger, is normally only expressed in two IC subtypes found in the convoluted tubule, the cortical collecting duct, and the connecting tubule. Beginning at 6 weeks of lithium treatment, we observed novel and various pendrin localization and expression patterns in the IMCD, including co‐expression with AQP4, a PC marker. These data collectively suggest that renal IMCD cell plasticity may play an important role in lithium‐induced IMCD remodeling.Support or Funding InformationNorman S. Coplon Extramural Grant ‐ Satellite Healthcare