Browsing by Author "Young-Stubbs, Cassandra M."
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Item Effect of selective ganglion stimulation on hypertension in systemic lupus erythematosus(2023) Johnson, Keanna; Dinh, Viet; Young-Stubbs, Cassandra M.; Shimoura, Caroline; Chaudhari, Sarika; Mathis, Keisa W.Effect of selective ganglion stimulation on hypertension in systemic lupus erythematosus Keanna K. Johnson1, Viet Dinh2, Cassandra M. Young-Stubbs2, Caroline G. Shimoura2, Sarika Chaudhari2, Keisa W. Mathis2 1School of Public Health,2Department of Physiology and Anatomy, University of North Texas Health Science Center, Fort Worth, Texas Purpose: Systemic lupus erythematous (SLE) is a female-dominant autoimmune disease that causes widespread inflammation in various organs. Inflammation precedes the prevalent hypertension in the disease. The cholinergic anti-inflammatory pathway (CAP) is an endogenous neuroimmune pathway that reduces inflammation upon stimulation. We hypothesize that stimulation of the CAP by selective activation of the superior cervical ganglion will halt disease progression and hypertension in SLE. Methods: Female SLE (NZBWF1) and control (NZW) mice received unilateral microinjections of pAAV-hSyn-hM3D(Gq)-mCherry, a designer receptor exclusively activated by designer drug (DREADD), or pAAV-hSyn-mCherry (vehicle) at the superior cervical ganglion (SCG) at 32 weeks of age. SCG DREADD injections generate muscarinic receptors on SCG neurons that are activated by the designer drug, clozapine N-oxide (CNO), ultimately leading to neuronal stimulation and potentially activation of the CAP. At 33 weeks of age, mice with SCG DREADD received a daily s.c. injection of CNO (3mg/kg) for two weeks. At 35 weeks, mice received a catheter implant in the carotid artery to measure mean arterial pressure (MAP) for two consecutive days followed by euthanasia and tissue collection. Plasma was collected biweekly via retro-orbital bleeding. Plasma samples were used to quantify double-stranded (ds) DNA autoantibodies. Results: dsDNA autoantibodies were higher in SLE than control mice (8.6e5 ± 1.8e5 vs. 5.1e4 ± 1.1e4 U/mL; p=0.0002; n=13). SCG DREADD did not change dsDNA autoantibody levels in SLE mice (1.1e6 ± 2.6e5 U/mL; p=0.1410; n=6) or control mice (5.4e4 ± 1.5e4 U/mL; p=0.6549; n=9). MAP was significantly higher in SLE mice compared to control mice (150 ± 9 vs. 122 ± 3 mmHg; p=0.0009; n=5–9). SCG DREADD did not change MAP in SLE mice (137 ± 2 mmHg; p=0.2572; n=6) or controls (127 ± 3 mmHg; p=0.7678; n=9). Conclusion: These data suggest that selective activation of the CAP at the level of the SCG using DREADD did not significantly alter disease severity or blood pressure in female SLE mice with advanced disease. Future studies will determine the effect of selective ganglion stimulation on inflammatory outcomes. Funding: Research reported in this abstract was supported by the National Heart, Lung, and Blood Institute of the National Institutes of Health under Award Number R25HL125447. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.Item Effect of Sigma-1 Receptor Activation on Renal Injury and Hypertension in Female Mice with Lupus(2023) Dinh, Viet; Chaudhari, Sarika; Young-Stubbs, Cassandra M.; Shimoura, Caroline; Tucker, Selina; Essajee, Salman; Warne, Cooper; Luedtke, Robert R.; Mathis, Keisa W.Systemic lupus erythematosus (SLE) is a female-dominant autoimmune disease with prominent renal injury and hypertension, contributing to its morbidity and mortality. Novel therapies to reduce these detrimental outcomes could be beneficial to SLE patients. The sigma-1 receptor (S1R) is a cytoprotective ligand-regulated chaperone protein that decreases protein aggregation, cellular stress, and cell death, thus preventing tissue injury. S1R activation with pharmacological ligands enhances cytoprotection in autoimmune diseases like multiple sclerosis and Huntington’s disease; however, the efficacy of S1R agonists in SLE is unknown. We hypothesize that S1R activation via the agonist LS-1-127 will reduce renal injury and halt the progression of hypertension in SLE mice. Female SLE (NZBWF1) and control (NZW) mice were weighed and urine collected via metabolic cages weekly starting at 30 weeks of age. Albuminuria was measured via dipsticks. At 33 weeks of age, SLE and control mice were treated with LS-1-127 (10 mg/kg IP) or equal volume of vehicle (10% DMSO; IP) three times a week for two weeks. At 35 weeks, mean arterial pressure (MAP) was measured in conscious mice using indwelling carotid catheters for two consecutive days and then mice were euthanized. Wire myography was used to assess potassium chloride (KCl)-induced contraction and acetylcholine (ACh)-induced relaxation in excised aorta. Markers of renal injury – urinary neutrophil gelatinase-associated lipocalin (NGAL), kidney injury molecule-1 (KIM-1), and creatinine – as well as plasma double-stranded (ds)DNA autoantibodies were measured by ELISA. Albuminuria was present in 44.4% (4 of 9) of SLE mice and no controls. LS-1-127 did not improve albuminuria in SLE mice (50%; 3 of 6). NGAL:creatinine ratio (ng/mg) was higher in SLE mice compared to controls (327.3 ± 119.8 vs 63.2 ± 4.3 ng/mg; n=9–12; P=0.0007). LS-1-127 did not significantly alter NGAL:creatinine ratio in SLE mice (484.3 ± 209.0; n=6) or controls (71.7 ± 5.2; n=10). KIM1:creatinine ratio (ng/mg) did not differ between groups. dsDNA autoantibodies were higher in SLE mice compared to controls (6.9e5 ± 1.1e5 vs. 1.4e5 ± 3.1e4 U/mL; n=9–10; P<0.0001). LS-1-127 did not significantly alter dsDNA autoantibodies in SLE mice (7.1e5 ± 1.2e5; n=6) or controls (1.5e5 ± 4.0e4; n=10). MAP was higher in SLE mice compared to controls (146 ± 4 vs. 123 ± 3 mmHg; n=9–10; P <0.0001). LS-1-127 did not significantly alter MAP in SLE mice (150 ± 8; n=6) or controls (124 ± 2; n=10). KCl-induced aortic contraction was similar in SLE and controls (21 ± 7 vs. 25 ± 4 mM, n=3–4). Sensitivity to KCl after LS-1-127 treatment was 11 ± 3 and 21 ± 2 mM in SLE and controls (n=2–4). ACh-induced aortic relaxation did not differ between groups. In conclusion, two weeks of S1R activation with LS-1-127 did not significantly alter markers of renal injury, autoimmunity, blood pressure, or vascular reactivity in female SLE mice with advanced disease. Further inquiry into the effect of LS-1-127 on the expression of renal proinflammatory cytokines will be conducted. S1R activation at different stages of SLE disease progression also warrants future investigation.Item Effect of systemic administration of α7-nicotinic acetylcholine receptor ligands on renal inflammation in young mice with systemic lupus erythematosus(2022) Brooks, Calvin D.; Young-Stubbs, Cassandra M.; Shimoura, Caroline; Dinh, Viet; Chaudhari, Sarika; Uteshev, Victor; Mathis, Keisa W.Systemic lupus erythematosus (SLE) is an autoimmune disease where renal inflammation contributes to hypertension. The cholinergic anti-inflammatory pathway is a recently described pathway where stimulating the vagus nerve causes release of acetylcholine from choline acetyltransferase (ChAT)+ T-cells in the spleen. This acetylcholine acts on alpha-7 nicotinic acetylcholine receptors (α7nAChR) of immune cells to hault the production of pro-inflammatory cytokines. Our lab has shown stimulation of this pathway at multiple levels lessens autoimmunity, renal inflammation and hypertension in SLE mice. However, our recent attempts to target the α7nAChR directly with a positive allosteric modulator (PAM) in mice with advanced SLE have not yielded similar results. This may be due to decreased parasympathetic tone in these mice in which the PAM is not able to compensate for. The aim of the current study was to determine if activating the α7nAChR in SLE mice at an earlier age, before dampening of parasympathetic tone, prevents the onset of hypertension and renal inflammation. Twelve week old female NZBWF1 mice, which spontaneously develop SLE, and NZW controls were given a partial agonist of the α7nAChR, GTS-21, a PAM, PNU-120596, or vehicle continuously for two weeks via subcutaneous osmotic mini-pump. Mean arterial pressure (MAP) was measured by carotid artery catheter in conscious, freely moving mice at 14 weeks. Mice were then euthanized and blood, spleen and kidneys harvested to allow measurement of plasma double stranded (ds) DNA autoantibodies via ELISA to assess severity of disease. There was no difference in dsDNA autoantibody activity (U/mL) between SLE mice and controls (all data presented as mean±SEM; 76026.3±38901.4 vs. 19617.4±4092.7; p=0.1141). The treatments had no effect on autoantibody activity in SLE mice [76026.3±38901.4 (SLE vehicle) vs. 36951.7±5962.3 (SLE PNU) vs. 56279.7±31381.0 (SLE GTS)] or controls [19617.4±4092.7 (Con vehicle) vs. 17293.2±3384.1 (Con PNU) vs. 16016.2±3059.6 (Con GTS)]. MAP (mmHg) did not differ significantly between young SLE and control mice (143.53±3.26 vs. 128.8±4.95). Additionally, the treatments had no effect on MAP of SLE mice [143.53±3.26 (SLE vehicle) vs. 128.32±10.92 (SLE PNU) vs. 129.56±19.50 (SLE GTS)] or controls [128.8±4.95 (Con vehicle) vs. 127.60±4.43 (Con PNU), vs. 125.65±5.54 (Con GTS)]. Based on these results, we suspect that the disease process has not progressed enough in 14-week-old mice to see differences due to these treatments. Although the changes in the blood pressure and dsDNA antibodies are not significant, we will continue to evaluate renal damage and cytokine profile to determine the effect of these α7nAChR ligands on pathogenesis of SLE. Future studies will aim to modulate α7nAChRs in SLE mice before the onset of disease (~12 weeks of age) through 35 weeks when mice usually experience terminal disease to determine efficacy of early activation of the cholinergic anti-inflammatory pathway in halting the progression of SLE.Item Renal TLR7 expression is associated with renal injury in female mouse model of systemic lupus erythematosus(2022) Chaudhari, Sarika; D'Souza, Bradley; Morales, Jessica; Shimoura, Caroline; Young-Stubbs, Cassandra M.; Ma, Rong; Mathis, Keisa W.Systemic lupus erythematosus (SLE) is an autoimmune disorder associated with exaggerated immune activation, autoantibody production, and immune complex formation. SLE patients are predominantly women of reproductive age that often present with end organ damage, specifically in the kidneys, and hypertension. This detrimental sequelae is likely due to deposition of the immune complexes and the resulting inflammation, but the exact mechanisms are unknown. It is known however that immune complexes activate toll like receptors (TLRs) on immune cells and TLR7 particularly is known to promote the pathogenesis of SLE. Therefore, we hypothesized that renal TLR7 impairs renal function and drives renal injury and hypertension in female SLE mice. Double-stranded DNA (dsDNA) autoantibodies, a hallmark of SLE, and albuminuria, a marker of renal injury, were monitored at 30 and 35 weeks of age in female and male SLE (NZBWF1) and control (NZW) mice. Glomerular filtration rate (GFR) was measured by sinistrin clearance and renal TLR7 and tumor necrosis factor (TNF)-α expression were measured via Western blot to assess renal function and renal inflammation at the end of 35 weeks. Mean arterial pressure was measured in conscious mice at 35 weeks of age using indwelling arterial catheters. At 30 weeks, female SLE mice had elevated plasma dsDNA autoantibodies (U/ml) compared to female controls (4.6e5 ± 1.3e5 vs 8.9e4 ± 3.3e4; n=3-5; all p< 0.05), male SLE mice (6.3e4 ± 2.7e4), and male controls (4.8e4 ± 9.3e3). At 30 weeks, 32% (7 out of 22) of female SLE mice had albuminuria versus 5% (1 out of 22) of female controls, 5% (1 out of 20) of male SLE, and no male controls. At 35 weeks, 63% (10 out of 16) of female SLE mice had albuminuria versus 5% (1 out of 22) of female controls, 5% (1 out of 19) of male SLE, and no male controls. GFR (µL/min/100 g body weight) was lower in female SLE mice compared to males at this same time point (865 ± 77 vs. 1066 ±60; p=0.029). Female SLE mice expressed a significantly higher renal cortical expression of TLR7 than both female control (p < 0.001) and male SLE mice (p < 0.001). Renal cortical expression of TNF-α, a downstream effector of TLR7, was increased in female SLE mice when compared to both female control mice (p < 0.001) and male SLE mice (p < 0.001). Both female and male SLE mice were hypertensive at 35 weeks: mean arterial pressure (mmHg) was higher in female SLE than female controls (152 ± 5 vs. 126 ± 3; n=6-8; p=0.003) and in male SLE compared to male controls (152 ± 4 vs. 136 ± 4 mmHg; n=6-11; p=0.041). These data indicate that increased expression of renal TLR7 and TNF-α is associated with renal injury and hypertension in female SLE mice. These data also suggest a potential sex difference in the pathogenesis of SLE in males. Therapeutic strategies targeting the TLR7 molecular pathway should be further investigated in both female and male lupus nephritis.Item Sex and strain differences in renal hemodynamics in mice(Wiley Periodicals, Inc., 2023-03-23) Tao, Yu; Young-Stubbs, Cassandra M.; Yazdizadeh Shotorbani, Parisa; Su, Dong-Ming; Mathis, Keisa W.; Ma, RongThe present study was to examine sex and strain differences in glomerular filtration rate (GFR) and renal blood flow (RBF) in C57BL6, 129/Sv, and C57BLKS/J mice, three commonly used mouse strains in renal research. GFR was measured by transdermal measurement of FITC-sinitrin clearance in conscious mice. RBF was measured by a flow probe placed in the renal artery under an anesthetic state. In C57BL6 mice, there were no sex differences in both GFR and RBF. In 129/Sv mice, females had significantly greater GFR than males at age of 24 weeks, but not at 8 weeks. However, males had higher RBF and lower renal vascular resistance (RVR). Similar to 129/Sv, female C57BLKS/J had significantly greater GFR at both 8 and 24 weeks, lower RBF, and higher RVR than males. Across strains, male 129/Sv had lower GFR and higher RBF than male C57BL6, but no significant difference in GFR and greater RBF than male C57BLKS/J. No significant difference in GFR or RBF was observed between C57BL6 and C57BLKS/J mice. Deletion of eNOS in C57BLKS/J mice reduced GFR in both sexes, but decreased RBF in males. Furthermore, there were no sex differences in the severity of renal injury in eNOS(-/-) dbdb mice. Taken together, our study suggests that sex differences in renal hemodynamics in mice are strain and age dependent. eNOS was not involved in the sex differences in GFR, but in RBF. Furthermore, the sexual dimorphism did not impact the severity of renal injury in diabetic nephropathy.Item Sex Differences in the Development of Hypertension in the Setting of Autoimmunity(2020) Morales, Jessica; Mathis, Keisa W.; Young-Stubbs, Cassandra M.; D'Souza, BradleyPurpose: Systemic lupus erythematosus (SLE) is a chronic autoimmune inflammatory disease associated with high risks of hypertension. We previously confirmed the disease develops later in life in male SLE mice compared to females (35 vs.< 30 weeks). We also found that both male and female SLE mice are hypertensive by 35 weeks and that this hypertension is linked to renal injury in females but not males; therefore, we aimed to investigate potential contributors to the latent sex difference. Toll-like receptor 7 (TLR7) is an immune mediator active in autoimmunity that instigates widespread tissue damage. We hypothesized that increased TLR7 promotes renal injury in female SLE mice and a different mechanism, potentially increased renal vascular resistance (RVR), is responsible for the hypertension in male SLE mice. Methods: Renal cortical expression of TLR7 was assessed via Western blot in male and female SLE mice (NZBWF1) at 35 weeks. Renal blood flow and mean arterial pressure were measured in anesthetized male and female SLE mice to determine RVR. Results: Female SLE mice had higher (p< 0.05) expression of TLR7 (2.6e6 ±5.4e5; normalized to total protein) than males (1.7e6 ± 3.3e5). Male SLE mice had lower RVR than females (5.15 ±0.60 vs. 10.07 ±1.23 mmHg·min·kg·mL-1). Conclusion: Our data suggest that while the hypertension in female SLE mice may be due to renal mechanisms, male SLE mice develop hypertension through other mechanisms. Future studies will continue to dissect sex-specific factors that should be considered when treating hypertensive patients with underlying chronic inflammation.Item Should Renal Inflammation Be Targeted While Treating Hypertension?(Frontiers Media S.A., 2022-06-13) Chaudhari, Sarika; Pham, Grace S.; Brooks, Calvin D.; Dinh, Viet Q.; Young-Stubbs, Cassandra M.; Shimoura, Caroline G.; Mathis, Keisa W.Despite extensive research and a plethora of therapeutic options, hypertension continues to be a global burden. Understanding of the pathological roles of known and underexplored cellular and molecular pathways in the development and maintenance of hypertension is critical to advance the field. Immune system overactivation and inflammation in the kidneys are proposed alternative mechanisms of hypertension, and resistant hypertension. Consideration of the pathophysiology of hypertension in chronic inflammatory conditions such as autoimmune diseases, in which patients present with autoimmune-mediated kidney inflammation as well as hypertension, may reveal possible contributors and novel therapeutic targets. In this review, we 1) summarize current therapies used to control blood pressure and their known effects on inflammation; 2) provide evidence on the need to target renal inflammation, specifically, and especially when first-line and combinatory treatment efforts fail; and 3) discuss the efficacy of therapies used to treat autoimmune diseases with a hypertension/renal component. We aim to elucidate the potential of targeting renal inflammation in certain subsets of patients resistant to current therapies.